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Hydrodynamic Characteristics of a Horizontal Pulsed Solvent Extraction Column
Alan J. Melnyk
A horizontal configuration for a pulsed solvent extraction contactor has been recognized as having a great potential in replacing standard vertical pulsed columns (VPC) in the separation of heavy elements in the reprocessing of spent nuclear fuel. Published work examining the performance of the horizontal pulsed column (HPC) has been sparse to date, thus preventing the design of large-scale units.
Hydrodynamic characteristics of a horizontal pulsed solvent extraction column
Alan Joseph Melnyk
A horizontal configuration for a pulsed solvent extraction contactor has been recognized as having a great potential in replacing standard vertical pulsed columns (VPC) in the separation of heavy elements in the reprocessing of spent nuclear fuel.^ Hydrodynamic behaviour was characterized in terms of throughput capacity, dispersed phase holdup, axial mixing of both phases and power dissipation. Emphasis in this
CFD modeling of sieve and pulsed-sieve plate extraction columns
Randheer L. Yadav; Ashwin W. Patwardhan
Present work deals with the development of a computational fluid dynamics (CFD) model for understanding the hydrodynamics in sieve and pulsed-sieve plate extraction columns. The model is based on Eulerian¢Eulerian approach along with standard k¢? model for turbulence. The CFD model has been validated by comparing (i) the height of the accumulated layer of the dispersed phase under the plate,
Study on the dynamic holdup distribution of the pulsed extraction column
Wang, S.; Chen, J.; Wu, Q. [Tsinghua University, Beijing 100084 (China)
In the study, a CSTR cascade dynamic hydraulic model was developed to investigate the dynamic holdup distribution of the pulsed extraction column. It is assumed that the dynamic process of the dispersed phase holdup of pulsed extraction column has equal effects with the operational process of multiple cascade CSTRs. The process is consistent with the following assumptions: the holdups vary on different stages but maintain uniform on each stage; the changes of the hydraulic parameters have impact initially on the inlet of dispersed phase, and stability will be reached gradually through stage-by-stage blending. The model was tested and verified utilizing time domain response curves of the average holdup. Nearly 150 experiments were carried out with different capillary columns, various feed liquids, and diverse continuous phases and under different operation conditions. The regression curves developed by the model show a good consistency with the experimental results. After linking parameters of the model with operational conditions, the study further found that the parameters are only linearly correlated with pulse conditions and have nothing to do with flow rate for a specific pulsed extraction column. The accuracy of the model is measured by the average holdup, and the absolute error is ▒0.01. The model can provide supports for the boundary studies on hydraulics and mass transfer by making simple and reliable prediction of the dynamic holdup distribution, with relatively less accessible hydraulic experimental data. (authors)
U(IV) and U(VI) extraction behavior in pulsed columns during off-standard operation
Munakata, K.; Nabeshima, M. (Sumitomo Metal Mining Co., Ltd., Tokai Research Center, 2600 Ishigamitojuku, Tokai-Mura, Ibaraki 319-11 (JP))
In this paper the behavior of U(IV) is pulsed columns during off-standard operation is studied. The effects of disturbances on the behavior of U(IV) and U(VI) are tested using extraction equipment. The experimental results show that disturbances induce a marked accumulation of U(IV). Furthermore, simulations are carried out with the DYNAC numerical calculation model. For U(VI) and nitric acid concentration, the simulated values are in good agreement with experimental values. There is, however, a tendency to underestimate the concentration of U(IV) in the organic phase when U(IV) distribution correlations based on available data are used. Temperature profiles are also predicted, and the estimated values agree well with the measured values. Therefore, it is confirmed that DYNAC is applicable to heat balance calculation.
Experimental validation of pulsed column inventory estimators
Beyerlein, A.L.; Geldard, J.F. (Clemson Univ., SC (United States)); Weh, R. (Gesellschaft fuer Nuklear-Service mbH, Hannover (Germany)); Eiben, K.; Dander, T. (Wiederaufbereitungsanlage Karlsruhe Betriebsgesellschaft mbH (WAK), Eggenstein-Leopoldshafen (Germany)); Hakkila, E.A. (Los Alamos National Lab., NM (United States))
Near-real-time accounting (NRTA) for reprocessing plants relies on the timely measurement of all transfers through the process area and all inventory in the process. It is difficult to measure the inventory of the solvent contractors; therefore, estimation techniques are considered. We have used experimental data obtained at the TEKO facility in Karlsruhe and have applied computer codes developed at Clemson University to analyze this data. For uranium extraction, the computer predictions agree to within 15% of the measured inventories. We believe this study is significant in demonstrating that using theoretical models with a minimum amount of process data may be an acceptable approach to column inventory estimation for NRTA. 15 refs., 7 figs.
Rapid Column Extraction Methods for Urine
Maxwell, S.L. III
A new fecal analysis method that dissolves plutonium oxide was developed at the Westinghouse Savannah River Site. Diphonix Resin (Eichrom Industries), is used to pre-concentrate the actinides from digested fecal samples. A rapid microwave digestion technique is used to remove the actinides from the Diphonix Resin, which effectively extracts plutonium and americium from acidic solutions containing hydrofluoric acid. After resin digestion, the plutonium and americium are recovered in a small volume of nitric acid that is loaded onto small extraction chromatography columns, TEVA Resin and TRU Resin (Eichrom Industries). The method enables complete dissolution of plutonium oxide and provides high recovery of plutonium and americium with good removal of thorium isotopes such as thorium-228.
Comparison of predicted and measured pulsed-column profiles and inventories
Ostenak, C.A.; Cermak, A.F.
Nuclear materials accounting and process control in fuels reprocessing plants can be improved by near-real-time estimation of the in-process inventory in solvent-extraction contactors. Experimental studies were conducted on pilot- and plant-scale pulsed columns by Allied-General Nuclear Service (AGNS), and the extensive uranium concentration-profile and inventory data were analyzed by Los Alamos and AGNS to develop and evaluate different predictive inventory techniques. Preliminary comparisons of predicted and measured pulsed-column profiles and inventories show promise for using these predictive techniques to improve nuclear materials accounting and process control in fuels reprocessing plants.
Optimization of the process for recovering caprolactam from wastewater in a pulsed-sieve-plate column using green design methodologies
Chao-Hong He; Yun-He Gao; Shuang-Hua Yang; David W. Edwards
In the process for recovering caprolactam from wastewater using a pulsed-sieve-plate column, benzene, which is used as the extracting solvent, may seriously impact the environment due to its emission during the normal operation of the process. Green design methodology is adopted to redesign the pulsed- sieve-plate column in the recovery process. The quantity of benzene is also optimized by green
Effect of pulsed-column-inventory uncertainty on dynamic materials accounting
Ostenak, C.A.
Reprocessing plants worldwide use the Purex solvent-extraction process and pulsed-column contactors to separate and purify uranium and plutonium from spent nuclear fuels. The importance of contactor in-process inventory to dynamic materials accounting in reprocessing plants is illustrated using the Allied-General Nuclear Services Plutonium Purification Process (PPP) of the now decommissioned Barnwell Nuclear Fuels Plant. This study shows that (1) good estimates of column inventory are essential for detecting short-term losses of in-process materials, but that (2) input-output (transfer) measurement correlations limit the accounting sensitivity for longer accounting periods (greater than or equal to 1 wk for the PPP). 6 refs., 2 figs., 3 tabs.
Pulsed Airborne Lidar Measurements of C02 Column Absorption
NASA Technical Reports Server (NTRS)
Abshire, James B.; Riris, Haris; Allan, Graham R.; Weaver, Clark J.; Mao, Jianping; Sun, Xiaoli; Hasselbrack, William E.; Rodriquez, Michael; Browell, Edward V.
We report on airborne lidar measurements of atmospheric CO2 column density for an approach being developed as a candidate for NASA's ASCENDS mission. It uses a pulsed dual-wavelength lidar measurement based on the integrated path differential absorption (IPDA) technique. We demonstrated the approach using the CO2 measurement from aircraft in July and August 2009 over four locations. The results show clear CO2 line shape and absorption signals, which follow the expected changes with aircraft altitude from 3 to 13 km. The 2009 measurements have been analyzed in detail and the results show approx.1 ppm random errors for 8-10 km altitudes and approx.30 sec averaging times. Airborne measurements were also made in 2010 with stronger signals and initial analysis shows approx. 0.3 ppm random errors for 80 sec averaging times for measurements at altitudes> 6 km.
Evaluation of Packed Columns in Supercritical Extraction ProcessesĀ
Rathkamp, P. J.; Fair, J. R.; Humphrey, J. L.
systems. In a mass transfer study at near-critical condi tions (60 atmospheres, 23 0 C), Schultz (13) built and operated a pilot plant extraction system using a 10-stage, 1.5 inch Scheibel column. The liquid' carbon dioxide solvent was used... to extract twelve model compounds (such as ethanol, ethyl butyrate, and limonene) from an aqueous feed. These compounds were used to simulate a model mixture of oranee essence. Schultz found that the feed rate had the largest effect on the percent...
J. Behmoiras; K. J. Bril; P. Krumholz
In the TBP--diluent-water systems, the distribution coefficients of all ; extractable species are severely depressed at high concentration levels of ; uranium in the organic phase. The highest degree of decontamination per each ; scrubbing stage of a discontinuous mixer-settler is obtained when nearly ; saturated TBP solutions in uranyl nitrate are used. However, using pulsed sieve-; plate extraction columns,
Extraction of rare earth metals with a multistage mixer-settler extraction column
Katsuroku Takahashi; Ahmed Abdel-Sattar Abdel-Tawab; Susumu Nii; Toshihiro Yajima; Fumio Kawaizumi
Extraction behavior of rare earth metals within a mixer¢settler extraction column has been analyzed with the stage efficiency calculated from mass transfer coefficients and interfacial area. The mass transfer coefficient within the dispersed drops is determined from a rigid sphere model by taking into account the residence time distribution of drops, and the coefficient around the drops is calculated by
Rapid Column Extraction method for SoilRapid Column Extraction method for Soil
Maxwell, Sherrod, L. III; Culligan, Brian K.
The analysis of actinides in environmental soil and sediment samples is very important for environmental monitoring as well as for emergency preparedness. A new, rapid actinide separation method has been developed and implemented that provides total dissolution of large soil samples, high chemical recoveries and effective removal of matrix interferences. This method uses stacked TEVA Resin{reg_sign}, TRU Resin{reg_sign} and DGA-Resin{reg_sign} cartridges from Eichrom Technologies (Darien, IL, USA) that allows the rapid separation of plutonium (Pu) neptunium (Np), uranium (U), americium (Am), and curium (Cm) using a single multi-stage column combined with alpha spectrometry. The method combines a rapid fusion step for total dissolution to dissolve refractory analytes and matrix removal using cerium fluoride precipitation to remove the difficult soil matrix. By using vacuum box cartridge technology with rapid flow rates, sample preparation time is minimized.
TECHNICAL ADVANCES A rapid column-based ancient DNA extraction method for
Reich, David
TECHNICAL ADVANCES A rapid column-based ancient DNA extraction method for increased sample-quality samples. Therefore, a DNA extraction method that optimizes DNA yields from low-quality samples a method that combines the high DNA yield of batch-based silica extraction with the time
Cavity Optical Pulse Extraction: ultra-short pulse generation as seeded Hawking radiation
Eilenberger, Falk; Kabakova, Irina V.; de Sterke, C. Martijn; Eggleton, Benjamin J.; Pertsch, Thomas
We show that light trapped in an optical cavity can be extracted from that cavity in an ultrashort burst by means of a trigger pulse. We find a simple analytic description of this process and show that while the extracted pulse inherits its pulse length from that of the trigger pulse, its wavelength can be completely different. Cavity Optical Pulse Extraction is thus well suited for the development of ultrashort laser sources in new wavelength ranges. We discuss similarities between this process and the generation of Hawking radiation at the optical analogue of an event horizon with extremely high Hawking temperature. Our analytic predictions are confirmed by thorough numerical simulations. PMID:24060831
Cavity Optical Pulse Extraction: ultra-short pulse generation as seeded Hawking radiation.
Eilenberger, Falk; Kabakova, Irina V; de Sterke, C Martijn; Eggleton, Benjamin J; Pertsch, Thomas
We show that light trapped in an optical cavity can be extracted from that cavity in an ultrashort burst by means of a trigger pulse. We find a simple analytic description of this process and show that while the extracted pulse inherits its pulse length from that of the trigger pulse, its wavelength can be completely different. Cavity Optical Pulse Extraction is thus well suited for the development of ultrashort laser sources in new wavelength ranges. We discuss similarities between this process and the generation of Hawking radiation at the optical analogue of an event horizon with extremely high Hawking temperature. Our analytic predictions are confirmed by thorough numerical simulations. PMID:24060831
Modeling of a pulsed fluid column and coupled piping with structural finite elements
NASA Technical Reports Server (NTRS)
Saxon, J. B.; Jones, J. U.; Anderson, F. E.
Structural finite elements have been used to model the coupled fluidic-structural response of a liquid oxygen (LOX) feedline at a rocket engine test facility. The model simulates the effects of Pogo pulsing, a test procedure which uses a piston in a side branch to impart an oscillatory pressure pulse to the LOX column as it feeds the engine. In addition to the feedline's structural characteristics, the model accounts for the mass and axial stiffness of the fluid column, the oscillatory pulse of the piston, and the hydraulic impedance of the rocket engine. The model was used to determine the relations between piston stroke, pressure oscillation at the engine inlet, and structural excitation of the feedline. This paper develops the concepts employed by the model.
Solid-phase extraction of plant thionins employing aluminum silicate based extraction columns.
Hussain, Shah; G³zel, Y³ksel; Pezzei, Cornelia; Rainer, Matthias; Huck, Christian W; Bonn, G³nther K
Thionins belong to a family of cysteine-rich, low-molecular-weight (?5 KDa) biologically active proteins in the plant kingdom. They display a broad cellular toxicity against a wide range of organisms and eukaryotic cell lines. Thionins protect plants against different pathogens, including bacteria and fungi. A highly selective solid-phase extraction method for plant thionins is reported deploying aluminum silicate (3:2 mullite) powder as a sorbent in extraction columns. Mullite was shown to considerably improve selectivity compared to a previously described zirconium silicate embedded poly(styrene-co-divinylbenzene) monolithic polymer. Due to the presence of aluminum(III), mullite offers electrostatic interactions for the selective isolation of cysteine-rich proteins. In comparison to zirconium(IV) silicate, aluminum(III) silicate showed reduced interactions towards proteins which resulted into superior washings of unspecific compounds while still retaining cysteine-rich thionins. In the presented study, European mistletoe, wheat and barley samples were subjected to solid-phase extraction analysis for isolation of viscotoxins, purothionins and hordothionins, respectively. Matrix-assisted laser desorption/ionization time of flight mass spectroscopy was used for determining the selectivity of the sorbent toward thionins. The selectively retained thionins were quantified by colorimetric detection using the bicinchoninic acid assay. For peptide mass-fingerprint analysis tryptic digests of eluates were examined. PMID:24913248
Study of Pulsed Columns with the System. Uranyl Nitrate-Nitric Acid-Water- Tributylphosphate; ETUDE DES COLONNES A PULSATIONS A L'AIDE DU SYSTEME NITRATE D'URANYLE-ACIDE NITRIQUEEAU-TRIBUTYLPHOSPHATE
J. Durandet; D. Defives; B. Choffe; Y. L. Gladel
The performsnce of a pulsed column with perforated plates was studied ; with the aid of a uranyl nitrate-nitric acid --water --tributyl phosphate system. ; The extraction of uranium from an aqueous acidic solution by an organic solvent ; and the extraction of uranium from organic solutions by water were the two cases ; investigated. The variation of the efficiency
Extreme degree of ionization in micro-capillary plasma columns heated by ultrafast current pulses
NASA Astrophysics Data System (ADS)
Rocca, Jorge; Li, Jing; Avaria, Gonzalo; Grisham, Michael; Tomasel, Fernando; Shlyaptsev, Vyacheslav
The efficient generation of dense large-scale plasma columns with very high degree of ionization and high homogeneity can enable fundamental plasma studies and a variety of promising applications. We demonstrate the generation of dense large-aspect-ratio plasmas columns with extremely high degree of ionization in micro-capillary channels heated by ultrafast discharge current pulses. Xenon plasma columns were ionized to the Co-like stage (Xe XXVIII) injecting 37 kA current pulses with 4 ns risetime into of 500 micrometer diameter, with lines from the Fe-like ion (Xe XXIX) also visible in the spectra. Sequences of time-resolved filtered pinhole images of the plasma column show a symmetric compression leading to 300: 1 aspect-ration plasma channels. The experimental results, that include ionization of Al impurities up to the H-like stage, support model simulations in showing that rapid ohmic heating of micro-capillary channels with relatively modest currents can generate very hot dense plasma columns which electron temperature could approach 1 KeV.
Power extraction from an oscillating water column along a coast
Martins-rivas, Hervķ
For reasons of wave climate, geography, construction, maintenance, energy storage and transmission, some devices for extracting energy from sea waves will likely be installed on the coast. We study here the specific case ...
Evaluation of Packed Columns in Supercritical Extraction Processes
Rathkamp, P. J.; Fair, J. R.; Humphrey, J. L.
rings. The SFE systems studied were carbon dioxide/ethanol/water and carbon digxide/isopropanol/water at 102 atmos pheres and 35 C and 102 atmospheres and 40 0 C, res pectively. In order to compare supercritical with conventional solvent extraction... to extract twelve model compounds (such as ethanol, ethyl butyrate, and limonene) from an aqueous feed. These compounds were used to simulate a model mixture of oranee essence. Schultz found that the feed rate had the largest effect on the percent...
Column chromatographic extraction and preparation of cordycepin from Cordyceps militaris waster medium.
Ni, He; Zhou, Xiao-Hong; Li, Hai-Hang; Huang, Wen-Fang
Large amounts of solid medium containing cordycepin, used in the industrial production of Cordyceps militaris through solid fermentation, are discarded as waste and contaminate the environment. We have developed a new column chromatographic extraction (CCE) method for the extraction of cordycepin from this waste and a preparation method for further separation and purification. Dried waste material was imbibed in four times its volume of water for 6 h, transferred to columns and eluted with water. Eluates were directly separated with macroporous resin DM130 columns followed by purification steps, including precipitation, crystallization, and polyamide column chromatography. Extraction rates of more than 97% were obtained with 12 volumes of water for a single column and 4 volumes of water for eluates circulated through 3 different columns designed to concentrate cordycepin. Cordycepin (98% pure) was obtained following the separation and purification processes, with an overall recovery rate of more than 90%. The CCE method has high extraction efficiency, uses a minimum volume of solvent and can be used for both quantitative analysis and large preparations of cordycepin from waste. The preparation method is simple, highly efficient, energy-saving, environmentally friendly, and has been demonstrated to be effective for large preparations of cordycepin from waste with low equipment and operating costs. PMID:19553164
On-line solid phase extraction for polycyclic aromatic hydrocarbons in soil column effluents
Weigand, H.; Koegel-Knabner, I. [Technische Universitaet Muenchen, Freising-Weihenstephan (Germany). Lehrstuhl fuer Bodenkunde; Totsche, K.U. [Univ. of Bayreuth (Germany). Soil Physics Div.
On-line solid phase extraction with C-18 cartridges provided a reliable method for the extraction of polycyclic aromatic hydrocarbons (PAHs) from soil column effluents. The on-line extraction was compared to the common off-line extraction of effluent fractions with respect to the mass recoveries of an internal standard. The effluent was obtained from a water unsaturated soil column under steady state water flow conditions. The column was packed with an artificially anthracene-contaminated soil material. The results showed superior and more reproducible PAH trapping when the on-line extraction was used. The PAH mass recoveries were unaffected by the range of dissolved organic carbon (DOC) concentrations covered in the experiment. This held true over a range of pHs and water unsaturated conditions of the C-18 material. By using the on-line extraction procedure, losses of PAHs due to sorption to the surfaces of collection vessels were avoided. The combination with a fraction collector allowed for the extraction of very small sample volumes. Thus, the method is suitable for an unbiased evaluation of PAH mobility in soil column experiments.
Relaxation of the pulsed opto-galvanic current signal in a helium positive column
Y. Yasuda; N. Sokabe; A. Murai
Transient behavior of an opto-galvanic (OG) current signal induced by pulsed dye laser excitation has been investigated on the He I 388.9-nm (2 3S-3 3P) transition in a He positive column. The OG current signal is composed of a sharp spike at the early time stage followed by a slowly-varying component. The decay time of the sharp OG current signal
Extraction of negative ions from pulsed electronegative capacitively coupled plasmas
Agarwal, Ankur; Rauf, Shahid; Collins, Ken [Applied Materials Inc., 974 E. Arques Avenue, M/S 81312, Sunnyvale, California 94085 (United States)
Charge buildup during plasma etching of dielectric features can lead to undesirable effects, such as notching, bowing, and twisting. Pulsed plasmas have been suggested as a method to achieve charge-free plasma etching. In particular, electronegative plasmas are attractive as the collapse of the plasma potential during the after-glow period of pulsed capacitively coupled plasmas (CCPs) can allow for extraction of negative ions into the feature. The extraction of negative ions in the after-glow of pulsed CCPs sustained in CF{sub 4} containing gas mixtures is computationally investigated. In this paper, the consequences of pulse frequency and gas chemistry on negative ion flux to the wafer are discussed. A low negative ion flux to the wafer was observed only in the late after-glow period of low pulse frequencies. The negative ion flux was found to significantly increase with the addition of highly electronegative gases (such as thermally attaching Cl{sub 2}) even at a high pulse frequency of 10 kHz. As the production of negative ions during the after-glow diminishes, alternative strategies to enhance the flux were also pursued. The flux of negative ions was found to increase by the addition of a pulsed dc voltage on the top electrode that is 180 Degree-Sign out-of-phase with the rf pulse.
[Preparation and applications of a supported liquid-liquid extraction column with a composite diatomite material].
Bao, Jianmin; Ma, Zhishuang; Sun, Ying; Wang, Yongzun; Li, Youxin
A rapid and special supported liquid-liquid extraction (SLE) column was developed with a composite diatomite material. The SLE column was evaluated by high performance liquid chromatography (HPLC) with acidic, neutral and alkaline compounds dissolved in water. Furthermore, some real complex samples were also analyzed by HPLC with the SLE method. The recoveries of benzoic acid (acidic), p-nitroaniline (alkaline) and 4-hydroxy-benzoic methyl ester (neutral) treated by the SLE column were 90.6%, 98.1% and 97.7%. However, the recoveries of the three compounds treated by traditional liquid-liquid extraction (LLE) method were 71.9%, 81.9% and 83.9%. The results showed that the SLE technique had higher recoveries than the traditional LLE method. The spiked recoveries of the complex samples, such as benzoic acid in Sprite and dexamethasone acetate, chlorphenamine maleate, indomethacin in bovine serum, were between 80% and 110% and the relative standard deviations (RSDs) were less than 15%. For biological specimen, the results could be accepted. Meantime, many disadvantages associated with traditional LLE method, such as emulsion formation, didn't occur using SLE column. The SLE column technique is a good sample preparation method with many advantages, such as rapid, simple, robust, easily automated, high recovery and high-throughput, which would be widely used in the future. PMID:23256382
Preparation and characterization of an immunoaffinity column for the selective extraction of salbutamol from pork sample.
Wang, Guomin; Li, Yingguo; Li, Xianliang; Wang, Xiong; Guo, Qi; Wu, Jizong; Xi, Cunxian; Li, Zhengguo
A rapid, simple, and reliable determination method for salbutamol in pork was developed with immunoaffinity column (IAC) extraction followed by HPLC analysis. The salbutamol immunoaffinity column was prepared by coupling CNBr-activated Sepharose-4B with the anti-salbutamol polyclonal antibody which was purified by caprylic acid-ammonium sulfate. The coupling rate of the antibody and Sepharose-4B was 98.6%, and the dynamic column capacity of IAC was 400 ng/mL gel. The average recoveries of salbutamol from spiked pork samples at levels of 2, 10, 20, and 50 ng/g ranged from 83.3% to 92.2%, with the relative standard deviations of 2.8-7.0% (n=5), and the limits of detection and qualification were 0.25 ng/g and 0.5 ng/g, respectively. PMID:21439117
Dynamics of a Finite Liquid Oxygen (LOX) Column in a Pulsed Magnetic Field
NASA Technical Reports Server (NTRS)
Youngquist, Robert; Immer, Christopher; Lane, John; Simpson, James; Steinrock, T. (Technical Monitor)
It is well known that liquid oxygen has a sufficient paramagnetic susceptibility that a strong magnetic field gradient can lift it in the earth's gravitational field. The movement of liquid oxygen is vital to the space program since it one of the primary oxidizers used for propulsion. Transport of liquid oxygen (LOX) via direct interaction of the magnetic fields (B field) with the fluid is a current topic of research and development at Kennedy Space Center, FL. This method of transporting (i.e. pumping) LOX may have particular advantages on Mars and other reduced gravitational environments, namely safety and reliability. This paper will address transport of a magnetic fluid, LOX, via phased-pulsed electromagnets acting on the edge of the column of fluid. The authors have developed a physical model from first-principles for the motion of a magnetic fluid in a particular U-tube geometry subjected to a pulsed magnetic field from an arbitrary solenoidal electromagnet. Experimental data that have been collected from the analogous geometry correlate well to that of the ab-initio calculations.
Improving carotenoid extraction from tomato waste by pulsed electric fields.
Luengo, Elisa; ┴lvarez, Ignacio; Raso, Javier
In this investigation, the influence of the application of pulsed electric fields (PEFs) of different intensities (3-7?kV/cm and 0-300??s) on the carotenoid extraction from tomato peel and pulp in a mixture of hexane:acetone:ethanol was studied with the aim of increasing extraction yield or reducing the percentage of the less green solvents in the extraction medium. According to the cellular disintegration index, the optimum treatment time for the permeabilization of tomato peel and pulp at different electric field strengths was 90??s. The PEF permeabilization of tomato pulp did not significantly increase the carotenoid extraction. However, a PEF treatment at 5?kV/cm improved the carotenoid extraction from tomato peel by 39% as compared with the control in a mixture of hexane:ethanol:acetone (50:25:25). Further increments of electric field from 5 to 7?kV/cm did not increase significantly the extraction of carotenoids. The presence of acetone in the solvent mixture did not positively affect the carotenoid extraction when the tomato peels were PEF-treated. Response surface methodology was used to determine the potential of PEF for reducing the percentage of hexane in a hexane:ethanol mixture. The application of a PEF treatment allowed reducing the hexane percentage from 45 to 30% without affecting the carotenoid extraction yield. The antioxidant capacity of the extracts obtained from tomato peel was correlated with the carotenoid concentration and it was not affected by the PEF treatment. PMID:25988115
Improving Carotenoid Extraction from Tomato Waste by Pulsed Electric Fields
Luengo, Elisa; ┴lvarez, Ignacio; Raso, Javier
In this investigation, the influence of the application of pulsed electric fields (PEFs) of different intensities (3¢7?kV/cm and 0¢300??s) on the carotenoid extraction from tomato peel and pulp in a mixture of hexane:acetone:ethanol was studied with the aim of increasing extraction yield or reducing the percentage of the less green solvents in the extraction medium. According to the cellular disintegration index, the optimum treatment time for the permeabilization of tomato peel and pulp at different electric field strengths was 90??s. The PEF permeabilization of tomato pulp did not significantly increase the carotenoid extraction. However, a PEF treatment at 5?kV/cm improved the carotenoid extraction from tomato peel by 39% as compared with the control in a mixture of hexane:ethanol:acetone (50:25:25). Further increments of electric field from 5 to 7?kV/cm did not increase significantly the extraction of carotenoids. The presence of acetone in the solvent mixture did not positively affect the carotenoid extraction when the tomato peels were PEF-treated. Response surface methodology was used to determine the potential of PEF for reducing the percentage of hexane in a hexane:ethanol mixture. The application of a PEF treatment allowed reducing the hexane percentage from 45 to 30% without affecting the carotenoid extraction yield. The antioxidant capacity of the extracts obtained from tomato peel was correlated with the carotenoid concentration and it was not affected by the PEF treatment. PMID:25988115
Comparison of customized spin-column and salt-precipitation finger-prick blood DNA extraction
Poh, Jun-Jie; Gan, SamuelĀKen-En
gDNA (genomic DNA extraction from blood is a fundamental process in many diagnostic, identification and research applications. Numerous extraction methods have been reported and are available commercially. However, there is insufficient understanding of the impact of chemical buffers on DNA yield from either whole or nucleated blood. Moreover, these commercial kits are often costly, constraining less well-funded laboratories to traditional and more cost-effective salt-precipitation methods. Towards this, we compared a salt-precipitation and a customized cost-effective spin-column-based method, studying the impact of different chemical constituents on the yields. This customized method resulted in a shortening of the extraction process, higher gDNA yields, and more successful PCR amplification of gDNA genes compared with the salt-precipitation method. Optimizing different chemical buffers on whole- and nucleated blood materials further revealed that certain chemicals boosted extractions from whole- but not nucleated blood. These findings may be useful to laboratories that do not have ready access to commercial kits, and improve their nucleic acid extractions from blood economically. PMID:25222694
Pulse Profiles, Accretion Column and a flare in Gx 1+4 During a Faint State
NASA Technical Reports Server (NTRS)
Giles, A. B.; Galloway, D. K.; Greenhill, J. G.; Storey, M. C.; Wilson, C. A.
The Rossi X-ray Timing Explorer (RXTE) spacecraft observed the X-ray pulsar GX 1+4 for a period of 34 hours on July 19/20 1996. The source faded from an intensity of approx. 20 mcrab to a minimum of less than or equal to 0.7 mcrab and then partially recovered towards the end of the observation. This extended minimum lasted approx. 40,000 seconds. Phase folded light curves at a barycentric rotation period of 124.36568 +/- 0.00020 seconds show that near the center of the extended minimum the source stopped pulsing in the traditional sense but retained a weak dip feature at the rotation period. Away from the extended minimum the dips are progressively narrower at higher energies and may be interpreted as obscurations or eclipses of the hot spot by the accretion column. The pulse profile changed from leading-edge bright before the extended minimum to trailing-edge bright after it. Data from the Burst and Transz'ent Source Experiment (BATSE) show that a torque reversal occurred less than 10 days after our observation. Our data indicate that the observed rotation departs from a constant period with a P/P value off approx. -5% per year at a 4.5(sigma) significance. We infer that we may have serendipitously obtained data. with high sensitivity and temporal resolution about the time of an accretion disk spin reversal. We also observed a rapid flare which had some precursor activity close to the center of the extended minimum.
Multiresidue analysis of quinolones and fluoroquinolones in soil by ultrasonic-assisted extraction in small columns and HPLC-UV
Esther Turiel; Antonio MartĒn-Esteban; Josķ Luis Tadeo
In this work, a new and simple analytical methodology for the simultaneous analysis of several quinolones (cinoxacin, oxolinic acid, nalidixic acid and flumequine) and fluoroquinolones (norfloxacin, enrofloxacin, enoxacin, ciprofloxacin and danofloxacin) in soil samples is presented. The method is based on the extraction of these analytes by an ultrasonic-assisted extraction in small columns and their subsequent quantification by HPLC using
Determination of magnolol and honokiol in Magnoliae Cortex using supercritical fluid chromatography on-line coupled with supercritical fluid extraction by on-column trapping
Keiichi Suto; Yuji Ito; Kazuhiko Sagara; Hideji Itokawa
An assay of magnolol and honokiol in Magnoliae Cortex was established by on-line supercritical fluid chromatography (SFC) coupled with supercritical fluid extraction (SFE).With an amino column as the trapping and separation column, magnolol and honokiol were extracted and focused at the column head as a narrow band, even if 5% methanol was added to the supercritical carbon dioxide as an
Short pulse high power microwave generation from an axially extracted virtual cathode oscillator
Rishi Verma; Anurag Shyam; Tushar Patel; Y. C. Saxena
* Abstract: Preliminary experimental results of an axially extracted virtual cathode oscillator (vircator) built on the low impedance pulsed electron beam accelerator AMBICA- 600 is reported. The AMBICA-600 pulsed power system mainly comprises of a coaxial waterline charged from single turn Tesla transformer. Waterline has impedance of ~5? and generates pulse width of ~60ns. The generated pulsed high power microwave
Retrievals of Column CO2 Densities from Pulsed Airborne Lidar Measurements
NASA Astrophysics Data System (ADS)
Weaver, C. J.; Abshire, J. B.; Allan, G.; Hasselbrack, W.; Kawa, S. R.; Mao, J.
We present results from our summer 2010 CO2 measurement campaign using the NASA Goddard CO2 lidar sounder onboard the NASA DC-8 aircraft platform. This instrument is a candidate for NASA's ASCENDS space mission. The airborne instrument steps a pulsed wavelength-tunable laser transmitter across the 1572.33 nm CO2 line in thirty steps at a 300 Hz repetition rate. The line transmission shape, optical depth, and column densities for the CO2 are obtained from a retrieval algorithm that fits the observed scan while accounting for atmospheric temperature, pressure, water vapor and the lidar's wavelength response. We present results from flights over Railroad Valley Nevada, the ARM site in Oklahoma, and a flight over the Pacific Ocean. During our most recent summer 2011 campaign we flew our instrument over solid and broken cloud as well as smoke from forest fires. Preliminary results from these more challenging conditions will be presented. A second part of the presentation asks how many independent pieces of information about the CO2 vertical profile are retrievable for a given CO2 lidar instrument configuration. We explore how changing the instrument signal to noise and changing the number of wavelengths where the absorption is measured impacts the amount of information in the retrieved CO2 vertical profile. For example if we want CO2 concentrations from 2 independent altitude layers how many wavelength samples, at a given signal to noise, are needed? We consider instrument configurations where only two wavelengths are sampled (simple on-line off-line) up to configurations where 30 wavelengths are sampled.
Bonded-phase extraction column isolation of organic compounds in groundwater at a hazardous waste site
Rostad, C.E.; Pereira, W.E.; Ratcliff, S.M.
A procedure for isolation of hazardous organic compounds from water for gas chromatography/mass spectrometry analysis Is presented and applied to creosote- and pentachlorophenol-contaminated groundwater resulting from wood-treatment processes. This simple procedure involved passing a 50-100-mL sample through a bonded-phase extraction column, eluting the trapped organic compounds from the column with 2-4 mL of solvent, and evaporating the sample to 100 ??L with a stream of dry nitrogen, after which the sample was ready for gas chromatography/mass spectrometry analysis. Representative compounds indicative of creosote contamination were used for recovery and precision studies from the cyclohexyl-bonded phase. Recovery of these compounds from n-octyl-, n-octadecyl-, cyclohexyl-, and phenyl-bonded phases was compared. The bonded phase that exhibited the best recovery and least bias toward acidic or basic cmpounds was the n-octadecyl phase. Detailed compound Identification Is given for compounds Isolated from creosote- and pentachlorophenol-contaminated groundwater using the cyclohexyl-bonded phase.
Selective, on-column extraction of organochlorine pesticide residues from milk.
Di Muccio, A; Rizzica, M; Ausili, A; Camoni, I; Dommarco, R; Vergori, F
A rapid procedure has been developed that allows a single-step, selective extraction of organochlorine pesticide (OCP) residues from milk on solid-matrix disposable columns by means of acetonitrile-saturated light petroleum. Recovery experiments were carried out on homogenized milk (3.6% fat content) spiked with an ethanolic solution of nine OCPs, viz., HCB, alpha-HCH, beta-HCH, gamma-HCH, heptachlor epoxide, dieldrin, endrin, p,p'-DDE and p,p'-DDT, at levels ranging from 0.002 mg/kg for alpha-HCH to 0.008 mg/kg for p,p'-DDT. Average recoveries of four replicates were 77% for HCB and almost quantitative (94-113%) for the other pesticides, with relative standard deviations from 2.9 to 7.3%. Coextracted fatty material amounted to about 5 mg/ml of milk before the clean-up. The described procedure also showed a satisfactory performance with milk powder. The extraction procedure requires about 60 min. The main advantages are that emulsions do not occur, several samples can be run in parallel by a single operator, reusable glassware is not needed and simple operations are required. PMID:3243863
[Validation study of a method for multiresidue analysis of pesticides in cereals and pulses using supercritical fluid extraction].
Uranishi, Katsushige; Yamashita, Hirokazu; Okayama, Akiko; Yamamoto, Keigo
Supercritical fluid extraction (SFE) was applied to extraction of pesticides from cereals and pulses. Residues were extracted from homogenized samples mixed with water-absorbent polymer and supercritical carbon dioxide in a stainless steel tube, followed by elution with acetonitrile. Co-extractives were removed by means of mini-column clean-up. Measurement was performed by GC-MS/MS. Calibration was achieved by preparing matrix-matched calibration standards to counteract matrix effects. With the Japanese method validation guideline for pesticide residues as a reference, the method was assessed in 5 agricultural products spiked with 334 pesticides at 0.01 and 0.1 Ąg/g. Compounds at each level were extracted from 2 samples on 5 separate days. The trueness of the method for 137 pesticides in all samples was 70-120%, and the repeatability and within-run reproducibility were also consistent with the guideline. The trueness of the method for the other 101 pesticides was in the range of 50-70%, though the repeatability and within-run reproducibility were satisfactory. This method is available as a multiresidue analysis method for cereals and pulses. PMID:23470855
Pulsed Lidar Measurements of Atmospheric CO2 Column Absorption in the ASCENDS 2011 Airborne Campaign
NASA Technical Reports Server (NTRS)
Abshire, James B.; Riris, Haris; Allan, Graham R.; Ramanathan, Anand; Hasselbrack, William E.; Mao, Jianping; Weaver, Clark; Browell, Edward V.
We have previously demonstrated an efficient pulsed, wavelength-resolved IPDA lidar technique for measuring the tropospheric CO2 concentrations as a candidate for NASA's ASCENDS mission. Our team participated in the 2010 ASCENDS airborne campaigns we flew airborne version of the CO2 and O2 lidar on the NASA DC-8. The CO2 lidar measures the atmospheric backscatter profiles and shape of the 1572.33 nm absorption line using 250 mW average laser power, 30 wavelength samples per scan and 300 scans per second. Most flights had 5-6 altitude steps to greater than 12 km, and clear CO2 line shapes were observed at all altitudes. Our post-flight analysis estimated the Iidar range and pulse energies at each wavelength every second. We then solved for the best-fit CO2 absorption line shape, and calculated the Differential Optical Depth (DOD) at the line peak. We compared these to CO2 DODs calculated from spectroscopy based on HITRAN 2008 and the conditions from airborne in-situ readings. Analysis of the 2010 measurements over the Pacific Ocean and Lamont OK shows the expected -linear change of the peak DOD with altitude. For measurements at altitudes greater than 6 km the random errors were approximately 0.3 ppm for 80 sec averaging times. After the 2010 flights we improved the airborne lidar's scan uniformity, calibration and receiver sensitivity. Our team participated in the seven ASCENDS science flights during late July and August 2011. These flights were made over a wide variety of surface and cloud conditions near the US, including over the central valley of California, over several mountain ranges, over both broken and solid stratus cloud deck over the Pacific Ocean, snow patches on mountain tops, over thin and broken clouds above the US Southwest and Iowa, and over forests near the WLEF tower in Wisconsin. Analyses show the retrievals of lidar range and CO2 column absorption, as wen as estimates of CO2 mixing ratio worked well when measuring over topography with rapidly changing height and reflectivity, through thin clouds and to stratus cloud tops. For regions where the CO2 concentration was relatively constant, the measured CO2 absorption profile (averaged for 50 sec) matched the predicted profile to better than 1% RMS error for all flight altitudes. For 1 & 10 second averaging, the scatter in the retrievals was limited by signal shot noise (i.e. the sigual photon count). Analysis to date shows the decrease in CO2 due to vegetation when flying easterward over the Great Plains as well as the increase in CO2 concentration in the vicinity ofthe coal-fired power plant in New Mexico. Examples of these and other results will be presented.
Separation and determination of 4-methylimidazole, 2-methylimidazole and 5-hydroxymethylfurfural in beverages by amino trap column coupled with pulsed amperometric detection.
Xu, Xian-Bing; Liu, Ding-Bo; Yu, Shu-Juan; Yu, Pei; Zhao, Zhen-Gang
A method for simultaneous determination of 4-methylimidazole (4-MeI), 2-methylimidazole (2-MeI) and 5-hydroxymethylfurfural (HMF) in beverages was developed using solid-phase extraction (SPE) and amino trap column coupled with pulsed amperometric detection (AMTC-PAD). A single amino trap column (P/N: 046122) was first applied to separate the targeted analytes in samples after SPE pretreatment. This method demonstrated low limit of quantification (0.030mg/L for methylimidazoles and 0.300mg/L for HMF) and excellent linearity with correlation of determination (R(2)=0.999 for 2-MeI, 0.997 for 4-MeI and 0.998 for HMF). Nearly no 2-MeI was found in all soft drinks. However, 4-MeI could be detected in cola drinks and soft drinks containing caramel colour (ranging from 0.13 to 0.34mg/L), whereas HMF were only found in cola drinks (ranging from 1.07 to 4.47mg/L). Thus, AMTC-PAD technique would be a valid and inexpensive alternative to analysis of 4-MeI, 2-MeI and HMF. PMID:25236220
Determination of commonly used herbicides in surface water using solid-phase extraction and dual-column HPLC-DAD.
Ozhan, G³l; Ozden, Sibel; Alpertunga, Buket
The present study describes the application of different solid-phase extraction techniques for the extraction, separation, and quantitative determination of 10 commonly used herbicides with different chemical structures (chlorsulfuron, diuron, bentazone, linuron, chlorpropham, fenoxoprop-ethyl, MCPA, diclofop-methyl, fluazifop-butyl, trifluraline) in water. Octadecyl (C(18)) Empore extraction disks, octadecyl (C(18)), and stryene divinylbenzene (SDB) Bond Elut Env cartridges were compared for solid-phase extraction efficiency. Herbicides were separated and quantified by reversed-phase high performance liquid chromatography with diode-array detection (HPLC-DAD) with simultaneous separation on two columns of differing polarity (C(18) and CN) to confirm identification. Analytical separation was performed simultaneously on C(18) and CN columns. Reanalysis of the sample extracts on a (cyano) CN column were used to confirm the identity of these compounds. Method optimization and validation parameters were presented in this work. Recoveries varied from 76.0% to 99.0% for C(18) disks, from 75.1% to 100.0% for C(18) cartridges, and from 54.0% to 98.0% for SDB cartridges over concentrations at 0.025--0.4 microg L(-1). The limits of detection were 0.012--0.035 microg L(-1). PMID:16194920
Extraction of cesium from an alkaline leaching solution of spent catalysts using an ion-exchange column
Dumont, N.; Favre-Reguillon, A.; Dunjic, B.; Lemaire, M. [Institut De Recherches sur la Catalyse et Laboratoire de Catalyse et Synthese Organique, Villeubanne (France)
The selective extraction of cesium from an alkaline leaching solution of spent catalysts using phenolic resins was studied. The resins were synthesized by alkaline polycondensation of formaldehyde by phenol, resorcinol, catechol, and phloroglucinol. Their ionoselectivities for five alkali metals were evaluated with a solid-liquid extraction, and their ion-exchange capacities were compared. The resin with the best selectivity for cesium was tested with a real solution at different pH values. An on-column extraction is proposed to obtain cesium with high purity.
Comparative study between extraction techniques and column separation for the quantification of sinigrin and total isothiocyanates in mustard seed.
Cools, Katherine; Terry, Leon A
Glucosinolates are ?-thioglycosides which are found naturally in Cruciferae including the genus Brassica. When enzymatically hydrolysed, glucosinolates yield isothiocyanates and give a pungent taste. Both glucosinolates and isothiocyanates have been linked with anticancer activity as well as antifungal and antibacterial properties and therefore the quantification of these compounds is scientifically important. A wide range of literature exists on glucosinolates, however the extraction and quantification procedures differ greatly resulting in discrepancies between studies. The aim of this study was therefore to compare the most popular extraction procedures to identify the most efficacious method and whether each extraction can also be used for the quantification of total isothiocyanates. Four extraction techniques were compared for the quantification of sinigrin from mustard cv. Centennial (Brassica juncea L.) seed; boiling water, boiling 50% (v/v) aqueous acetonitrile, boiling 100% methanol and 70% (v/v) aqueous methanol at 70 ░C. Prior to injection into the HPLC, the extractions which involved solvents (acetonitrile or methanol) were freeze-dried and resuspended in water. To identify whether the same extract could be used to measure total isothiocyanates, a dichloromethane extraction was carried out on the sinigrin extracts. For the quantification of sinigrin alone, boiling 50% (v/v) acetonitrile was found to be the most efficacious extraction solvent of the four tested yielding 15% more sinigrin than the water extraction. However, the removal of the acetonitrile by freeze-drying had a negative impact on the isothiocyanate content. Quantification of both sinigrin and total isothiocyanates was possible when the sinigrin was extracted using boiling water. Two columns were compared for the quantification of sinigrin revealing the Zorbax Eclipse to be the best column using this particular method. PMID:22743340
Method for making a non-extractable stationary phase of polymer within a capillary column
Springston, S.R.
A method is described for coating interior capillary column surfaces, or packing material of a packed column, used for gas chromatography, with a stationary polymer phase that is cross-linked by exposing it to a low-temperature plasma that is uniformly distributed over the column or packing material for a predetermined period of time to effect the desired degree of cross-linking of the coating. 7 figs.
Analysis of Pulsed Airborne Lidar Measurements of Atmospheric CO2 Column Absorption from 3-13 km Altitudes
NASA Technical Reports Server (NTRS)
Abshire, James B.; Weaver, Clark J.; Riris, Haris; Mao, Jianping; Sun, Xiaoli; Allan, Graham R.; Hasselbrack, William; Browell, Edward V.
We have developed a pulsed lidar technique for measuring the tropospheric CO2 concentrations as a candidate for NASA's ASCENDS space mission [1]. It uses two pulsed laser transmitters allowing simultaneous measurement of a CO2 absorption line in the 1575 nm band, O2 extinction in the Oxygen A-band, surface height and backscatter profile. The lasers are precisely stepped in wavelength across the CO2 line and an O2 line region during the measurement. The direct detection receiver measures the energies of the laser echoes from the surface along with the range profile of scattering in the path. The column densities for the CO2 and O2 gases are estimated from the ratio of the on- and off-line signals via the integrated path differential absorption (IPDA) technique. The time of flight of the laser pulses is used to estimate the height of the scattering surface and to reject laser photons scattered in the atmosphere. We developed an airborne lidar to demonstrate an early version of the CO2 measurement from the NASA Glenn Lear-25 aircraft. The airborne lidar stepped the pulsed laser's wavelength across the selected CO2 line with 20 wavelength steps per scan. The line scan rate is 450 Hz, the laser pulse widths are 1 usec, and laser pulse energy is 24 uJ. The time resolved laser backscatter is collected by a 20 cm telescope, detected by a NIR photomultiplier and is recorded on every other reading by a photon counting system [2]. During August 2009 we made a series of 2.5 hour long flights and measured the atmospheric CO2 absorption and line shapes using the 1572.33 nm CO2 line. Measurements were made at stepped altitudes from 3-13 km over locations in the US, including the SGP ARM site in Oklahoma, central Illinois, north-eastern North Carolina, and over the Chesapeake Bay and the eastern shore of Virginia. Although the received signal energies were weaker than expected for ASCENDS, clear CO2 line shapes were observed at all altitudes, and some measurements were made through thin clouds. The Oklahoma and east coast flights were coordinated with a LaRC/ITT CO2 lidar on the LaRC UC-12 aircraft, and in-situ measurements were made using its CO2 sensor and radiosondes. We have conducted an analysis of the ranging and IPDA lidar measurements from these four flights. Most flights had 5-6 altitude steps with 200-300 seconds of recorded measurements per step. We used a cross-correlation approach to process the laser echo records. This was used to estimate the range to the scattering surface, to define the edges of the laser pulses and to determine echo pulse energy at each wavelength. We used a minimum mean square approach to fit an instrument response function and to solve for the best-fit CO2 absorption line shape. We then calculated the differential optical depth (DOD) of the fitted CO2 line. We computed its statistics at the various altitude steps, and compare them to the DODs calculated from spectroscopy based on HITRAN 2008 and the column conditions calculated from the airborne in-situ readings. The results show the lidar and in-situ measurements have very similar DOD change with altitude and greater than 10 segments per flight where the scatter in the lidar measurements are less than or equal to 1ppm. We also present the results from subsequent CO2 column absorption measurements, which were made with stronger detected signals during three flights on the NASA DC-8 over the southwestern US in during July 2010.
Fluidized-bed column method for automatic dynamic extraction and determination of trace element bioaccessibility in highly heterogeneous solid wastes
MarĒa Rosende; Manuel Mir¾; VĒctor CerdÓ
Dynamic flow-through extraction\\/fractionation methods have recently drawn much attention as appealing alternatives to the batchwise steady-state counterparts for the evaluation of environmentally available pools of potentially hazardous trace elements in solid matrices. The most critical weakness of flow-based column approaches lies in the small amount of solid that can be handled, whereby their applicability has been merely limited to date
Forest fire smog feature extraction based on Pulse-Coupled neural network
Wu Jiang; Huang Rule; Xu Ziyue; Han Ning
A novel algorithm for image-based forest fire smog feature extraction based on Pulse-Coupled neural network (PCNN) is proposed. The PCNN is derived from the phenomena of synchronous pulse burst in mammals' visual cortex. The outputs of PCNN represent unique features of imported images, and has been proved to be invariant to translation, rotation and distortion. In this paper the image
Magnetic pulsed extraction of highly charged ions from a plateau ECRIS
L. M³ller; A. Heinen; H. W. Ortjohann; H. J. Andrõ
The afterglow is known to produce pulses of highly charged ions suited for injection to accelerator facilities. We tested a new technique of magnetic pulsed extraction (PUMAEX) in our plateau-ECR ion source PECRIS III. This source has a large resonance volume due to a homogeneous magnetic field in its center. Compared to the afterglow of PECRIS III we reached higher
Binary solvent extraction system and extraction time effects on phenolic antioxidants from kenaf seeds (Hibiscus cannabinus L.) extracted by a pulsed ultrasonic-assisted extraction.
Wong, Yu Hua; Lau, Hwee Wen; Tan, Chin Ping; Long, Kamariah; Nyam, Kar Lin
The aim of this study was to determine the best parameter for extracting phenolic-enriched kenaf (Hibiscus cannabinus L.) seeds by a pulsed ultrasonic-assisted extraction. The antioxidant activities of ultrasonic-assisted kenaf seed extracts (KSE) were determined by a 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging capacity assay, 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulphonic acid) (ABTS) radical scavenging assay, ? -carotene bleaching inhibition assay, and ferric reducing antioxidant power (FRAP) assay. Total phenolic content (TPC) and total flavonoid content (TFC) evaluations were carried out to determine the phenolic and flavonoid contents in KSE. The KSE from the best extraction parameter was then subjected to high performance liquid chromatography (HPLC) to quantify the phenolic compounds. The optimised extraction condition employed 80% ethanol for 15?min, with the highest values determined for the DPPH, ABTS, and FRAP assay. KSE contained mainly tannic acid (2302.20?mg/100?g extract) and sinapic acid (1198.22?mg/100?g extract), which can be used as alternative antioxidants in the food industry. PMID:24592184
Effects of pulsed UV-light on peanut allergens in extracts and liquid peanut butter.
Technology Transfer Automated Retrieval System (TEKTRAN)
Pulsed ultraviolet (PUV)-light, a non-thermal technology, was used to treat both peanut extracts and liquid peanut butter. The objective was to determine if such treatment would lead to a reduction in the allergenic potency of the peanut extract and butter. Peanut samples were PUV treated, using a X...
Use of pulsed ultraviolet light to reduce the allergenic potency of soybean extracts.
Technology Transfer Automated Retrieval System (TEKTRAN)
Pulsed ultraviolet light (PUV), a non-thermal food processing technology, is reported to be able to inactivate enzymes and reduce allergen levels from peanut extracts. The objective of this study was to determine if PUV would reduce the allergen levels and allergenic potency of soy extracts. Soy ext...
Comparison of Alkaline Lysis with Electroextraction and Optimization of Electric Pulses to Extract Plasmid DNA
Ljubljana, University of
Comparison of Alkaline Lysis with Electroextraction and Optimization of Electric Pulses to Extract. Differ- ent pDNA extraction methods have been described; among them is alkaline lysis, currently the most commonly used. Although alkaline lysis represents an established method for isolation of pDNA, some
Pulsed Airborne Lidar Measurements of Atmospheric CO2 Column Absorption and Line Shapes from 3-13 km Altitudes
NASA Technical Reports Server (NTRS)
Abshire, James; Riris, Haris; Allan, Graham; Weaver, Clark; Mao, Jianping; Sun, Xiaoli; Hasselbrack, William
We have developed a pulsed lidar technique for measuring the tropospheric CO2 concentrations as a candidate for NASA's planned ASCENDS space mission. Our technique uses two pulsed laser transmitters allowing simultaneous measurement of a CO2 absorption line in the 1570 nm band, O2 extinction in the Oxygen A-band and surface height and backscatter. The lidar measures the energy and time of flight of the laser echoes reflected from the atmosphere and surface. The lasers are rapidly and precisely stepped in wavelength across the CO2 line and an O2 line region during the measurement. The direct detection receiver uses a telescope and photon counting detectors, and measures the background light and energies of the laser echoes from the surface along with scattering from any aerosols in the path. The gas extinction and column densities for the CO2 and O2 gases are estimated from the ratio of the on- and off- line signals via the DIAL technique. Time gating is used to isolate the laser echo signals from the surface, and to reject laser photons scattered in the atmosphere. The time of flight of the laser pulses are also used to estimate the height of the scattering surface and to identify cases of mixed cloud and ground scattering. We have developed an airborne lidar to demonstrate the CO2 measurement from the NASA Glenn Lear-25 aircraft. The airborne lidar steps the pulsed laser's wavelength across the selected CO2 line with 20 steps per scan. The line scan rate is 450 Hz, the laser pulse widths are 1 usec, and laser pulse energy is 24 uJ. The time resolved laser backscatter is collected by a 20 cm telescope, detected by a photomultiplier and is recorded by a photon counting system. We made initial airborne measurements on flights during fall 2008. Laser backscatter and absorption measurements were made over a variety of land and water surfaces and through thin clouds. The atmospheric CO2 column measurements using the 1572.33 nm CO2 lines. Two flights were made above the US Department of Energy's (DOE) SGP ARM site at altitudes from 3-8 km. These flights were coordinated with DOE investigators who flew an in-situ CO2 sensor on a Cessna aircraft under the path. The increasing CO2 line absorptions with altitudes were evident and comparison with in-situ measurements showed agreements to 6 ppm. In spring 2009 we improved the aircraft's nadir window and during July and August we made 9 additional 2 hour long flights and measured the atmospheric CO2 absorption and line shapes using the 1572.33 nm CO2 line. Measurements were made at stepped altitudes from 3-13 km over a variety of surface types in Nebraska, Illinois, the SGP ARM site, and near and over the Chesapeake Bay in North Carolina and eastern Virginia. Strong laser signals and clear CO2 line shapes were observed at all altitudes, and some measurements were made through thin clouds. The flights over the ARM site were underflown with in-situ measurements made from the DOE Cessna. Analysis shows that the average signal levels follow predicted values, the altimetry measurements had an uncertainty of about 4 m, and that the average optical line depths follow the number density calculated from in-situ sensor readings. The Oklahoma and east coast flights were coordinated with a LaRC/ITT CO2 lidar on the LaRC UC-12 aircraft, a LaRC in-situ CO2 sensor, and the Oklahoma flights also included a JPL CO2 lidar on a Twin Otter aircraft. More details of the flights, measurements, analysis and scaling to space will be described in the presentation.
Airborne Measurements of CO2 Column Concentration and Range Using a Pulsed Direct-Detection IPDA Lidar
NASA Technical Reports Server (NTRS)
Abshire, James B.; Ramanathan, Anand; Riris, Haris; Mao, Jianping; Allan, Graham R.; Hasselbrack, William E.; Weaver, Clark J.; Browell, Edward V.
We have previously demonstrated a pulsed direct detection IPDA lidar to measure range and the column concentration of atmospheric CO2. The lidar measures the atmospheric backscatter profiles and samples the shape of the 1,572.33 nm CO2 absorption line. We participated in the ASCENDS science flights on the NASA DC-8 aircraft during August 2011 and report here lidar measurements made on four flights over a variety of surface and cloud conditions near the US. These included over a stratus cloud deck over the Pacific Ocean, to a dry lake bed surrounded by mountains in Nevada, to a desert area with a coal-fired power plant, and from the Rocky Mountains to Iowa, with segments with both cumulus and cirrus clouds. Most flights were to altitudes >12 km and had 5-6 altitude steps. Analyses show the retrievals of lidar range, CO2 column absorption, and CO2 mixing ratio worked well when measuring over topography with rapidly changing height and reflectivity, through thin clouds, between cumulus clouds, and to stratus cloud tops. The retrievals shows the decrease in column CO2 due to growing vegetation when flying over Iowa cropland as well as a sudden increase in CO2 concentration near a coal-fired power plant. For regions where the CO2 concentration was relatively constant, the measured CO2 absorption lineshape (averaged for 50 s) matched the predicted shapes to better than 1% RMS error. For 10 s averaging, the scatter in the retrievals was typically 2-3 ppm and was limited by the received signal photon count. Retrievals were made using atmospheric parameters from both an atmospheric model and from in situ temperature and pressure from the aircraft. The retrievals had no free parameters and did not use empirical adjustments, and >70% of the measurements passed screening and were used in analysis. The differences between the lidar-measured retrievals and in situ measured average CO2 column concentrations were <1.4 ppm for flight measurement altitudes >6 km.
Extracting Concrete Thermal Characteristics from Temperature Time History of RC Column Exposed to Standard Fire
A numerical method to identify thermal conductivity from time history of one-dimensional temperature variations in thermal unsteady-state is proposed. The numerical method considers the change of specific heat and thermal conductivity with respect to temperature. Fire test of reinforced concrete (RC) columns was conducted using a standard fire to obtain time history of temperature variations in the column section. A thermal equilibrium model in unsteady-state condition was developed. The thermal conductivity of concrete was then determined by optimizing the numerical solution of the model to meet the observed time history of temperature variations. The determined thermal conductivity with respect to temperature was then verified against standard thermal conductivity measurements of concrete bricks. It is concluded that the proposed method can be used to conservatively estimate thermal conductivity of concrete for design purpose. Finally, the thermal radiation properties of concrete for the RC column were estimated from the thermal equilibrium at the surface of the column. The radiant heat transfer ratio of concrete representing absorptivity to emissivity ratio of concrete during fire was evaluated and is suggested as a concrete criterion that can be used in fire safety assessment. PMID:25180197
Development of an immunoaffinity chromatography column for selective extraction of a new agonist phenylethylamine A from feed, meat and liver samples.
Mei, Liyun; Cao, Biyun; Yang, Hong; Xie, Yun; Xu, Shouming; Deng, Anping
Phenylethanolamine A (PA) is a new emerged ?-adrenergic agonist that has been illegally used as an animal feed additive for growth promotion in China. In this study, an immunoaffinity chromatography (IAC) column for selective extraction of PA from swine feed, meat and liver samples was developed. The IAC column was constructed by covalently coupling specific polyclonal antibody (Ab) against PA to CNBr-activated Sepharose 4B and packed into a common solid phase extraction (SPE) cartridge. The extraction conditions including loading, washing and eluting solutions were carefully optimized. Under optimal conditions, the IAC column was characterized in terms of maximum capacity, selectivity, extraction recovery and stability. The maximum capacity of the ICA for PA extraction was found to be 239.4ng. For selectivity testing, 100ng of other three ?-adrenergic agonists (clenbuterol, ractopamine and salbutamol) was separately loaded onto the column, and it was observed that the tested compounds could not be captured on the column, e.g. the column could only selectively recognize PA. The recovery of the IAC for PA extraction was found within 96.47-101.98% when 10, 50 and 100ng PA were separately loaded onto IAC column. The IAC column was also applied to real sample extraction. Swine feed, meat and liver samples were collected and spiked with PA in range of 1.0-20ngg(-1). The spiked and unspiked samples were extracted by IAC column and measured by high performance liquid chromatography (HPLC). It was found that there was no detectable PA in the blank samples, and the extraction recoveries of the IAC for PA from the spiked samples were within 89.48-104.89%. The stability of the column was also tested. It was showed that after 35 times repeated usage, 60% of the maximum capacity was still remained. The proposed IAC was proven to be a feasible extraction method for PA from different matrices with the properties of high maximum capacity, selectivity, extraction efficiency and stability. PMID:24342511
A study of solvent refining of cottonseed oil by use of a rotating core countercurrent extraction columnĀ
Holbrook, Charles Ray
A STUDY OF SOLVENT REFINING OF COTTONSEED OIL BY USE OF A ROTATING CORE COUNTERCURRENT EXTRACTION COLUMN A Thes1s by C. Ray Holbrook January- 1953 Approved as to style and content: aS a rman o u en s omm ee ea o epar men em ca -ng neer ng... 4 STUDY OP SOLVENT REFININO OP COTKWSE89 OIL BY USE OF A ROTLTINQ CORE COUNTERCURRENT EXTINCTION COLUNN k Thesis Subaaitteg to the Paculty of the Agricultural and Mechanical College of Texaa Partial Pulfillment of the Requireaents...
Analysis of Pulsed Lidar Measurements of Atmospheric CO2 Column Absorption During the ASCENDS 2009-2011 Airborne Campaigns
NASA Technical Reports Server (NTRS)
Abshire, J. B.; Weaver, C. J.; Riris, H.; Mao, J.; Sun, X; Allan, G. R.; Hasselbrack, W. E.; Browell, E. V.
We have developed a pulsed lidar technique for measuring the tropospheric CO2 concentrations as a candidate for NASA's ASCENDS mission and have demonstrated the CO2 and O2 measurements from aircraft. Our technique uses two pulsed lasers allowing simultaneous measurement of a single CO2 absorption line near 1572 nm, O2 extinction in the Oxygen A-band, surface height and backscatter profile. The lasers are stepped in wavelength across the CO2 line and an O2 line doublet during the measurement. The column densities for the CO2 and O2 are estimated from the differential optical depths (DOD) of the scanned absorption lines via the IPDA technique. For the 2009 ASCENDS campaign we flew the CO2 lidar on a Lear-25 aircraft, and measured the absorption line shapes of the CO2 line using 20 wavelength samples per scan. Measurements were made at stepped altitudes from 3 to 12.6 km over the Lamont OK, central Illinois, North Carolina, and over the Virginia Eastern Shore. Although the received signal energies were weaker than expected for ASCENDS, clear CO2 line shapes were observed at all altitudes. Most flights had 5-6 altitude steps with 200-300 seconds of recorded measurements per step. We averaged every 10 seconds of measurements and used a cross-correlation approach to estimate the range to the scattering surface and the echo pulse energy at each wavelength. We then solved for the best-fit CO2 absorption line shape, and calculated the DOD of the fitted CO2 line, and computed its statistics at the various altitude steps. We compared them to CO2 optical depths calculated from spectroscopy based on HITRAN 2008 and the column number densities calculated from the airborne in-situ readings. The 2009 measurements have been analyzed and they were similar on all flights. The results show clear CO2 line shape and absorption signals, which follow the expected changes with aircraft altitude from 3 to 13 km. They showed the expected nearly the linear dependence of DOD vs altitude. The measurements showed 1 ppm random errors for 8-10 km altitudes and 30 sec averaging times. For the 2010 ASCENDS campaigns we flew the CO2lidar on the NASA DC-8 and added an 02lidar channel. During July 2010 we made measurements of CO2 and O2 column absorption during longer flights over Railroad Valley NV, the Pacific Ocean and over Lamont OK. CO2 measurements were made with 30 steps/scan, 300 scans/sec and improved line resolution and receiver sensitivity. Analysis of the 2010 CO2 measurements shows the expected linear change of DOD with altitude. For measurements at altitudes> 6 km the random errors were 0.3 ppm for 80 sec averaging times. For the summer 2011 ASCENDS campaigns we made further improvements to the lidar's CO2 line scan and receiver sensitivity. We demonstrated measurements over the California Central Valley, to stratus cloud tops over the Pacific Ocean, over mountain regions with snow, and over several areas with broken clouds. Details of the lidar measurements and their analysis will be described in the presentation.
Pulsed Lidar Measurements of Atmospheric CO2 Column Absorption and Range During the ASCENDS 2009-2011 Airborne Campaigns
NASA Technical Reports Server (NTRS)
Abshire, J. B.; Weaver, C. J.; Riris, H.; Mao, J.; Sun, X.; Allan, G. R.; Hasselbrack, W. E.; Browell, E. V.
We have developed a pulsed lidar technique for measuring the tropospheric CO2 concentrations as a candidate for NASA's ASCENDS mission and have demonstrated the CO2 and O2 measurements from aircraft. Our technique uses two pulsed lasers allowing simultaneous measurement of a single CO2 absorption line near 1572 nm, O2 extinction in the Oxygen A-band, surface height and backscatter profile. The lasers are stepped in wavelength across the CO2 line and an O2 line doublet during the measurement. The column densities for the CO2 and O2 are estimated from the differential optical depths (DOD) of the scanned absorption lines via the IPDA technique. For the 2009 ASCENDS campaign we flew the CO2 lidar only on a Lear-25 aircraft, and measured the absorption line shapes of the CO2 line using 20 wavelength samples per scan. Measurements were made at stepped altitudes from 3 to 12.6 km over the Lamont OK, central Illinois, North Carolina, and over the Virginia Eastern Shore. Although the received signal energies were weaker than expected for ASCENDS, clear C02 line shapes were observed at all altitudes. Most flights had 5-6 altitude steps with 200-300 seconds of recorded measurements per step. We averaged every 10 seconds of measurements and used a cross-correlation approach to estimate the range to the scattering surface and the echo pulse energy at each wavelength. We then solved for the best-fit CO2 absorption line shape, and calculated the DOD of the fitted CO2 line, and computed its statistics at the various altitude steps. We compared them to CO2 optical depths calculated from spectroscopy based on HITRAN 2008 and the column number densities calculated from the airborne in-situ readings. The 2009 measurements have been analyzed in detail and they were similar on all flights. The results show clear CO2 line shape and absorption signals, which follow the expected changes with aircraft altitude from 3 to 13 km. They showed the expected nearly the linear dependence of DOD vs altitude. The measurements showed -1 ppm random errors for 8-10 km altitudes and -30 sec averaging times. For the 2010 ASCENDS campaigns we flew the CO2 lidar on the NASA DC-8 and added an O2 lidar channel. During July 2010 we made measurements of CO2 and O2 column absorption during longer flights over Railroad Valley NV, the Pacific Ocean and over Lamont OK. CO2 measurements were made with 30 steps/scan, 300 scans/sec and improved line resolution and receiver sensitivity. Analysis of the 2010 CO2 measurements shows the expected -linear change of DOD with altitude. For measurements at altitudes> 6 km the random errors were 0.3 ppm for 80 sec averaging times. For the summer 2011 ASCENDS campaigns we made further improvements to the lidar's CO2 line scan and receiver sensitivity. The seven flights in the 2011 Ascends campaign were flown over a wide variety of surface and cloud conditions in the US, which produced a wide variety of lidar signal conditions. Details of the lidar measurements and their analysis will be described in the presentation.
Extraction of quadrature phase information from multiple pulse NMR signals
NASA Technical Reports Server (NTRS)
Rhim, W.-K.; Burum, D. P.; Vaughan, R. W.
A multiple pulse sequence (8-pulse sequence) used for high-resolution solid state NMR is analyzed with regard to the information available from each of the four wide sampling windows. It is demonstrated that full quadrature phase information can be obtained using only a single phase detector and that, for the commonly encountered situation where the spectral width is much less than the folding frequency, the signals from the various windows can be combined easily using standard complex Fourier transform software. An improvement in the signal-to-noise ratio equal to the square root of 3 is obtained over either standard single or quadrature phase detection schemes. Procedures for correcting spectral distortions are presented.
[Determination of free formaldehyde in cosmetics by pre-column derivatization, extraction inhibition and high performance liquid chromatography].
L³, Chunhua; Huang, Chaoqun; Chen, Mei; Xie, Wen; Chen, Xiaomei
Pre-column derivatization and inhibition by solvent extraction were applied to determine free formaldehyde in cosmetics by high performance liquid chromatography (HPLC). Due to the rapid decomposition of formaldehyde donors in the derivatization, it is hard to detect the amount of the free formaldehyde in cosmetics. The formaldehyde directly reacted with 2,4-dinitrophenylhydrazine in acetonitrile-phosphate buffer (pH 2) (1:1, v/v) solution for 2 min, then dichloromethane extraction was used to induce the decomposition of formaldehyde donors. The extract was diluted with acetonitrile and then determined by HPLC. The formaldehyde derivative was separated on an Agilent C18 column (250 mm x 4.6 mm, 5 microm) at 30 degrees C with acetonitrile-water (60:40, v/v) as mobile phase at a flow rate of 1.0 mL/min, and detected at the wavelength of 355 nm. The recoveries were from 81% to 106% at the spiked levels of 50, 100, 500, 1 000 microg/g of formaldehyde in shampoo, milk, cream, hand cleaner, toothpaste, nail polish, powder separately, and the relative standard deviations (n = 6) were less than 5.0%. The limit of quantification of the formaldehyde in cosmetics was 50 microg/g. The method has been applied to the determination of free formaldehyde in real samples and the results showed that the release by formaldehyde donors was inhibited. The method has the advantages of simple operation, good accuracy and meets the requirement of determination of free formaldehyde in cosmetics. PMID:23593888
Enhanced anthocyanin extraction from red cabbage using pulsed electric field processing.
Gachovska, Tanya; Cassada, David; Subbiah, Jeyamkondan; Hanna, Milford; Thippareddi, Harshavardhan; Snow, Daniel
This study was conducted to evaluate the effect of pulsed electric field (PEF) treatment on anthocyanin extraction from red cabbage using water as a solvent. Mashed cabbage was placed in a batch treatment chamber and subjected to PEF (2.5 kV/cm electric field strength; 15 micros pulse width and 50 pulses, specific energy 15.63 J/g). Extracted anthocyanin concentrations (16 to 889 microg/mL) were determined using HPLC. Heat and light stabilities of the control and PEF-treated samples, having approximately the same initial concentrations, were studied. PEF treatments enhanced total anthocyanin extraction in water from red cabbage by 2.15 times with a higher proportion of nonacylated forms than the control (P < 0.05). The heat and light stabilities of the PEF-treated samples and control samples were not significantly different (P > 0.05). Practical Application: An innovative pretreatment technology, pulsed electric field processing, enhanced total anthocyanin extraction in water from red cabbage by 2.15 times. Manufacturers of natural colors can use this technology to extract anthocyanins from red cabbage efficiently. PMID:20722916
Pulsed Airborne Lidar Measurements of Atmospheric CO2 Column Absorption and Line Shapes from 3-13 km Altitudes
NASA Technical Reports Server (NTRS)
Abshire, J. B.; Riris, H.; Allan, G. R.; Weaver, C.; Hasselbrack, W.; Sun, X.
We have developed a lidar technique for measuring the tropospheric C02 concentrations as a candidate for NASA's planned ASCENDS mission. Our technique uses two pulsed laser transmitters allowing simultaneous measurement of a C02 absorption line in the 1570 nm band, 02 extinction in the Oxygen A-band and surface height and backscatter. The lidar measures the energy and time of flight of the laser echoes reflected from the atmosphere and surface. The lasers are stepped in wavelength across the C02 line and an 02 line region during the measurement. The receiver uses a telescope and photon counting detectors, and measures the background light and energies of the laser echoes from the surface along with scattering from any aerosols in the path. The gas extinction and column densities for the C02 and 02 gases are estimated from the ratio of the on- and off- line signals via the DIAL technique. Time gating is used to isolate the laser echo signals from the surface, and to reject laser photons scattered in the atmosphere. We have developed an airborne lidar to demonstrate the C02 measurement from the NASA Glenn Lear 25 aircraft. The airborne lidar steps the pulsed laser's wavelength across a selected C02 line with 20 steps per scan. The line scan rate is 450 Hz and laser pulse widths are I usec. The time resolved laser backscatter is collected by a 20 cm telescope, detected by a photomultiplier and is recorded by a photon counting system. We made initial airborne measurements on flights during October and December 2008. Laser backscatter and absorption measurements were made over a variety of land and water surfaces and through thin and broken clouds. Atmospheric C02 column measurements using the 1571.4, 1572.02 and 1572.33 nm C02 lines. Two flights were made above the DOE SGP ARM site at altitudes from 3-8 km. These nights were coordinated with DOE investigators who Hew an in-situ C02 sensor on a Cessna aircraft under the path. The increasing C02 line absorptions with altitudes were evident and comparison with in-situ measurements showed agreements to 6 ppm. This spring we improved the aircraft's nadir window. During July and August 2009 we made 9 additional 2 hour long flights and measured the atmospheric C02 absorption and line shapes using the 1572.33 nm C02 line. Measurements were made at stepped altitudes from 3-13 km over a variety of surface types in Nebraska, Illinois, the SGP ARM site, and near and over the Chesapeake Bay in North Carolina and Virginia. Strong laser signals and clear line shapes were observed at all altitudes, and some measurements were made through thin clouds. The flights over the ARM site were underflown with in-situ measurements made from the DOE Cessna. The Oklahoma and east coast t1ights were coordinated with a LaRC/ITT C02 lidar on the LaRC UC-12 aircraft, a LaRC insitu C02 sensor, and the Oklahoma flights also included a JPL C02 lidar on a Twin Otter aircraft. Ed Browell and Gary Spiers led the LaRC and JPL teams. More details of the t1ights, measurements and analysis will be described in the presentation.
Effect of pulsed electric field treatments on permeabilization and extraction of pigments from Chlorella vulgaris.
Luengo, Elisa; Cond¾n-Abanto, Santiago; ┴lvarez, Ignacio; Raso, Javier
The effect of pulsed electric field (PEF) treatments of different intensities on the electroporation of the cytoplasmatic membrane of Chlorella vulgaris, and on the extraction of carotenoids and chlorophylls were investigated. Staining the cells with propidium iodide before and after the PEF treatment revealed the existence of reversible and irreversible electroporation. Application of PEF treatments in the range of 20-25 kV cm(-1) caused most of the population of C. vulgaris to be irreversibly electroporated even at short treatment times (5 pulses of 3 Ąs). However, at lower electric field strengths (10 kV cm(-1)), cells that were reversibly electroporated were observed even after 50 pulses of 3 Ąs. The electroporation of C. vulgaris cells by PEF higher than 15 kV cm(-1) and duration is higher than 15 Ąs increased significantly the extraction yield of intracellular components of C. vulgaris. The application of a 20 kV cm(-1) for 75 ?s increased the extraction yield just after the PEF treatment of the carotenoids, and chlorophylls a and b 0.5, 0.7, and 0.8 times, respectively. However, further increments in electric field strength and treatment time did not cause significant increments in the extraction yield. The extraction of carotenoids from PEF-treated C. vulgaris cells after 1 h of the application of the treatment significantly increased the extraction yield in comparison to the yield obtained from the cells extracted just after the PEF treatment. After PEF treatment at 20 kV cm(-1) for 75 Ąs, extraction yield for carotenoids, and chlorophylls a and b increased 1.2, 1.6, and 2.1 times, respectively. A high correlation was observed between irreversible electroporation and percentage of yield increase when the extraction was conducted after 1 h of the application of PEF treatment (R: 0.93), but not when the extraction was conducted just after PEF treatment (R: 0.67). PMID:24880235
Determination of ricin by nano liquid chromatography/mass spectrometry after extraction using lactose-immobilized monolithic silica spin column.
Kanamori-Kataoka, Mieko; Kato, Haruhito; Uzawa, Hirotaka; Ohta, Shigenori; Takei, Yoshiyuki; Furuno, Masahiro; Seto, Yasuo
Ricin is a glycosylated proteinous toxin that is registered as toxic substance by Chemical Weapons convention. Current detection methods can result in false negatives and/or positives, and their criteria are not based on the identification of the protein amino acid sequences. In this study, lactose-immobilized monolithic silica extraction followed by tryptic digestion and liquid chromatography/mass spectrometry (LC/MS) was developed as a method for rapid and accurate determination of ricin. Lactose, which was immobilized on monolithic silica, was used as a capture ligand for ricin extraction from the sample solution, and the silica was supported in a disk-packed spin column. Recovery of ricin was more than 40%. After extraction, the extract was digested with trypsin and analyzed by LC/MS. The accurate masses of molecular ions and MS/MS spectra of the separated peptide peaks were measured by Fourier transform-MS and linear iontrap-MS, respectively. Six peptides, which were derived from the ricin A-(m/z 537.8, 448.8 and 586.8) and B-chains (m/z 701.3, 647.8 and 616.8), were chosen as marker peptides for the identification of ricin. Among these marker peptides, two peptides were ricin-specific. This method was applied to the determination of ricin from crude samples. The monolithic silica extraction removed most contaminant peaks from the total ion chromatogram of the sample, and the six marker peptides were clearly detected by LC/MS. It takes about 5 h for detection and identification of more than 8 ng/ml of ricin through the whole handling, and this procedure will be able to deal with the terrorism using chemical weapon. PMID:21834021
Extraction of Intercellular Components by Pulsed Electric Fields
E. Vorobiev; N. I. Lebovka
\\u000a During the last decades there was observed a growing interest in electric field application for treatment of food and agricultural\\u000a raw materials. In early studies of Russian researchers the electrical treatment was applied for intensification of the process\\u000a of juice extraction from fruits and vegetables (Flaumenbaum, 1949), for sugar diffusion from beet (Zagorulko, 1958), and as a promising method of
Direct extraction of coherent mode properties from imaging measurements in a linear plasma column
Light, A. D.; Sechrest, Y.; Munsat, T. [Center for Momentum Transport and Flow Organization, University of California San Diego, La Jolla, California 92093 (United States) [Center for Momentum Transport and Flow Organization, University of California San Diego, La Jolla, California 92093 (United States); Center for Integrated Plasma Studies, Department of Physics, University of Colorado Boulder, Boulder, Colorado 80309 (United States); Thakur, S. C.; Brandt, C.; Tynan, G. R. [Center for Momentum Transport and Flow Organization, University of California San Diego, La Jolla, California 92093 (United States) [Center for Momentum Transport and Flow Organization, University of California San Diego, La Jolla, California 92093 (United States); Department of Mechanical and Aerospace Engineering and Center for Energy Research, University of California San Diego, La Jolla, California 92093 (United States)
Spectral properties of coherent waves in an argon plasma column are examined using fluctuation data from fast imaging. Visible light from ArII line emission is collected at high frame rates using a high-speed digital camera. A cross-spectral phase technique allows direct visualization of dominant phase structures as a function of frequency, as well as identification of azimuthal asymmetries present in the system. Experimental dispersion estimates are constructed from imaging data alone. Drift-like waves are identified by comparison with theoretical dispersion curves, and a tentative match of a low-frequency spectral feature to Kelvin-Helmholtz-driven waves is presented. Imaging measurements are consistent with previous results, and provide non-invasive, single-shot measurements across the entire plasma cross-section. Implications of the measured spectral properties for imaging measurements of mode dynamics are explored.
A pressure-driven column-based technique for the efficient extraction of DNA from respiratory samples.
Hirama, Takashi; Mogi, Hajime; Egashira, Hitoshi; Yamamoto, Eiji; Kukisaki, Shigenari; Hagiwara, Koichi; Takei, Osamu
Currently molecular techniques are a broadly accepted tool for diagnosis and are able to benefit patients in clinical practice. The polymerase chain reaction (PCR) has been especially incorporated into practical applications that are already in widespread use across the globe. With regard to the initial DNA extraction from clinically relevant samples, a number of commercially available kits are commonly used and are also designed to be easy to handle and less labor-intensive. In this study, the pressure system extracting DNA in column-based kit was developed, and its utility was compared with the centrifuge method using sputum from patients who were diagnosed with pneumonia. Also, due to the compact size and rapid processing time, the practical application of the pressure-based system incorporated into an automated pipetting machine was evaluated through clinical study. Our data suggests that DNA extraction by pressure was capable of serving as a substitute for the centrifuge method, and the compact and automatic nature of the pressure system device provided rapid and valuable information for clinical practice. PMID:25824633
Monolithic spin column: a new extraction device for analysis of drugs in urine and serum by GC/MS and HPLC/MS.
Namera, Akira; Nagao, Masakata; Nakamoto, Akihiro; Miyazaki, Shota; Saito, Takeshi
A monolithic spin column was developed for the extraction of analytes from biological materials. This column was constructed by packing a monolithic silica disk into a spin column. Sample loading, washing, and elution of the target drugs were accomplished simply by centrifugation of the column. Opiates and benzodiazepines are abused throughout the world. Identification and quantification of these drugs is very important to solve crimes or the cause of death. Three opiates (morphine, codeine, and dihydrocodeine) were extracted from urine and serum by using the column. After conversion to trimethylsilyl derivatives of the opiates by vigorous mixing with the derivatizing reagent, the solution was subjected to GC/MS. A linear curve was observed for opiates from 10 to 2500 ng/mL in urine and 5 to 1200 ng/mL in serum, respectively (correlation coefficient > 0.996). For benzodiazepines, the hydroxyl metabolites of triazolam and etizolam were extracted from urine using the column, and the eluate was directly analyzed by HPLC/MS without evaporation. The LOD values were at the ppb level, with RSD values lower than 15%. The proposed methods were successfully applied to clinical and forensic cases, and good agreement of results was obtained compared to conventional methods. PMID:21797004
Optimisation of pulsed ultrasonic and microwave-assisted extraction for curcuminoids by response surface methodology and kinetic study.
Li, Ming; Ngadi, Michael O; Ma, Ying
A response surface methodology and a kinetic study were used to optimise the pulsed ultrasonic and microwave techniques in the extraction of curcuminoids. Microwave-assisted extraction had the same efficiency as pulsed ultrasonic-assisted extraction, and both methods were better than continuous ultrasonic extraction of curcuminoids. For the pulsed ultrasonic-assisted extraction, the optimal conditions were 60% amplitude (AMP), 83% ethanol (v/v), 3/1 (s/s) pulsed duration/interval time and 10 min irradiation time. For the microwave-assisted extraction, the optimal conditions were 82% ethanol, 10% power level and 7 min of extraction time. Both methods used a 1:200 mass to solvent ratio. PMID:25038645
Phytochemical and active column fractions of Pyrenacantha staudtii leaf extracts on isolated rat uterus.
Falodun, A; Usifoh, C O; Nworgu, Z A M
Four methanolic leaf fraction extracts of Pyrenacantha staudtii obtained from accelerated gradient chromatography (AGC) were tested on the isolated rat uterus. Various fractions--M1, M2, M3 and M4 through bioassay guided isolation were obtained. Fractions M(2) and M(4), containing saponins and alkaloids respectively, significantly (P<0.05) exerted high smooth muscle relaxant activity on the uterus. Fractions M(1) and M(3) containing fatty acids and tannins respectively did not exhibit significant effect on the isolated rat uterus. The results indicate the presence of active principles in the leaf extracts of P. staudtii which may be responsible for some of the applications in traditional medicines as remedy against threatened abortion and dysmenorrheal. PMID:16380355
Extracting breathing rate information from a wearable reflectance pulse oximeter sensor
W. S. Johnston; Y. Mendelson
The integration of multiple vital physiological measurements could help combat medics and field commanders to better predict a soldier's health condition and enhance their ability to perform remote triage procedures. In this paper we demonstrate the feasibility of extracting accurate breathing rate information from a photoplethysmographic signal that was recorded by a reflectance pulse oximeter sensor mounted on the forehead
Effect of Pulsed Ultraviolet Light and High Hydrostatic Pressure on the Antigenicity of Almond Protein Extracts.
Technology Transfer Automated Retrieval System (TEKTRAN)
The efficacy of pulsed ultraviolet light (PUV) and high hydrostatic pressure (HHP) on reducing the IgE binding to the almond extracts, was studied using SDS-PAGE, Western Blot, and ELISA probed with human plasma containing IgE antibodies to almond allergens, and a polyclonal antibody against almond ...
Simulating ion beam extraction from a single aperture triode acceleration column: A comparison of the beam transport codes IGUN and PBGUNS with test stand data
Patel, A.; Wills, J. S. C.; Diamond, W. T. [Chalk River Laboratories, AECL, Chalk River, Ontario K0 J 1J0 (Canada)
Ion beam extraction from two different ion sources with single aperture triode extraction columns was simulated with the particle beam transport codes PBGUNS and IGUN. For each ion source, the simulation results are compared to experimental data generated on well-equipped test stands. Both codes reproduced the qualitative behavior of the extracted ion beams to incremental and scaled changes to the extraction electrode geometry observed on the test stands. Numerical values of optimum beam currents and beam emittance generated by the simulations also agree well with test stand data.
Exploring the effects of pulsed electric field processing parameters on polyacetylene extraction from carrot slices.
Aguil¾-Aguayo, Ingrid; Abreu, Corina; Hossain, Mohammad B; Altisent, Rosa; Brunton, Nigel; Vi±as, Inmaculada; Rai, Dilip K
The effects of various pulsed electric field (PEF) parameters on the extraction of polyacetylenes from carrot slices were investigated. Optimised conditions with regard to electric field strength (1-4 kV/cm), number of pulses (100-1500), pulse frequency (10-200 Hz) and pulse width (10-30 ?s) were identified using response surface methodology (RSM) to maximise the extraction of falcarinol (FaOH), falcarindiol (FaDOH) and falcarindiol-3-acetate (FaDOAc) from carrot slices. Data obtained from RSM and experiments fitted significantly (p < 0.0001) the proposed second-order response functions with high regression coefficients (R2) ranging from 0.82 to 0.75. Maximal FaOH (188%), FaDOH (164.9%) and FaDOAc (166.8%) levels relative to untreated samples were obtained from carrot slices after applying PEF treatments at 4 kV/cm with 100 number of pulses of 10 ?s at 10 Hz. The predicted values from the developed quadratic polynomial equation were in close agreement with the actual experimental values with low average mean deviations (E%) ranging from 0.68% to 3.58%. PMID:25738537
Computer Simulation of Global Profiles of Carbon Dioxide Using a Pulsed, 2-Micron, Coherent-Detection, Column-Content DIAL System
NASA Technical Reports Server (NTRS)
Kavaya, Michael J.; Singh, Upendra N.; Koch, Grady J.; Yu, Jirong; Frehlich, Rod G.
We present preliminary results of computer simulations of the error in measuring carbon dioxide mixing ratio profiles from earth orbit. The simulated sensor is a pulsed, 2-micron, coherent-detection lidar alternately operating on at least two wavelengths. The simulated geometry is a nadir viewing lidar measuring the column content signal. Atmospheric absorption is modeled using FASCODE3P software with the HITRAN 2004 absorption line data base. Lidar shot accumulation is employed up to the horizontal resolution limit. Horizontal resolutions of 50, 100, and 200 km are shown. Assuming a 400 km spacecraft orbit, the horizontal resolutions correspond to measurement times of about 7, 14, and 28 s. We simulate laser pulse-pair repetition frequencies from 1 Hz to 100 kHz. The range of shot accumulation is 7 to 2.8 million pulse-pairs. The resultant error is shown as a function of horizontal resolution, laser pulse-pair repetition frequency, and laser pulse energy. The effect of different on and off pulse energies is explored. The results are compared to simulation results of others and to demonstrated 2-micron operating points at NASA Langley.
Determination of Wastewater Compounds in Sediment and Soil by Pressurized Solvent Extraction, Solid-Phase Extraction, and Capillary-Column Gas Chromatography/Mass Spectrometry
Burkhardt, Mark R.; Zaugg, Steven D.; Smith, Steven G.; ReVello, Rhiannon C.
A method for the determination of 61 compounds in environmental sediment and soil samples is described. The method was developed in response to increasing concern over the effects of endocrine-disrupting chemicals in wastewater and wastewater-impacted sediment on aquatic organisms. This method also may be used to evaluate the effects of combined sanitary and storm-sewer overflow on the water and sediment quality of urban streams. Method development focused on the determination of compounds that were chosen on the basis of their endocrine-disrupting potential or toxicity. These compounds include the alkylphenol ethoxylate nonionic surfactants and their degradates, food additives, fragrances, antioxidants, flame retardants, plasticizers, industrial solvents, disinfectants, fecal sterols, polycyclic aromatic hydrocarbons, and high-use domestic pesticides. Sediment and soil samples are extracted using a pressurized solvent extraction system. The compounds of interest are extracted from interfering matrix components by high-pressure water/isopropyl alcohol extraction. The compounds were isolated using disposable solid-phase extraction (SPE) cartridges containing chemically modified polystyrene-divinylbenzene resin. The cartridges were dried with nitrogen gas, and then sorbed compounds were eluted with methylene chloride (80 percent)-diethyl ether (20 percent) through Florisil/sodium sulfate SPE cartridge, and then determined by capillary-column gas chromatography/mass spectrometry. Recoveries in reagent-sand samples fortified at 4 to 72 micrograms averaged 76 percent ?13 percent relative standard deviation for all method compounds. Initial method reporting levels for single-component compounds ranged from 50 to 500 micrograms per kilogram. The concentrations of 20 out of 61 compounds initially will be reported as estimated with the 'E' remark code for one of three reasons: (1) unacceptably low-biased recovery (less than 60 percent) or highly variable method performance (greater than 25 percent relative standard deviation), (2) reference standards prepared from technical mixtures, or (3) potential blank contamination. Samples were preserved by freezing to -20 degrees Celsius. The U.S. Geological Survey National Water Quality Laboratory has established a 1-year sample-holding time limit (prior to sample extraction) from the date of sample collection (if the sample is kept at -20?C) until a statistically accepted method can be used to determine the effectiveness of the sample-freezing procedure.
The application of micro-column solid phase extraction techniques for the determination of rare earth elements in actinide containing matrices
K. P. Carney; D. G. Cummings
The design and characterization of an argon segmented-solid phase extraction system is described. A 200 ul volume micro-column has been constructed for the preconcentration of rare earth elements (REEs) from salt matrices containing uranium. An inductively coupled plasma atomic emission spectrometer has been utilized for simultaneous detection of Sr, Y and the REEs (namely Ce, Eu, La, Nd, Pr, Sm)
On the efficiency of emission from a plasma column in high-pressure pulse-periodic discharge in cesium
NASA Astrophysics Data System (ADS)
Baksht, F. G.; Lapshin, V. F.
Spectral energy fluxes emerging from the surface of an axially symmetric column of inhomogeneous cesium high-pressure plasma have been calculated by direct integration of the radiation-transport equation. It is shown that, at a specified plasma temperature on the axis, irrespective of the radiation -formation mechanism and the radial distribution of the plasma parameters, the maximum energy fluxes arise when the radial optical thickness ? R of the plasma column is close to unity. The asymptotic ? R value, at which the discharge column radiation is the largest part of the Planck radiation, has been found.
Rapid tea catechins and caffeine determination by HPLC using microwave-assisted extraction and silica monolithic column.
Rahim, A A; Nofrizal, S; Saad, Bahruddin
A rapid reversed-phase high performance liquid chromatographic method using a monolithic column for the determination of eight catechin monomers and caffeine was developed. Using a mobile phase of water:acetonitrile:methanol (83:6:11) at a flow rate of 1.4 mL min(-1), the catechins and caffeine were isocratically separated in about 7 min. The limits of detection and quantification were in the range of 0.11-0.29 and 0.33-0.87 mg L(-1), respectively. Satisfactory recoveries were obtained (94.2-105.2 ▒ 1.8%) for all samples when spiked at three concentrations (5, 40 and 70 mg L(-1)). In combination with microwave-assisted extraction (MAE), the method was applied to the determination of the catechins and caffeine in eleven tea samples (6 green, 3 black and 2 oolong teas). Relatively high levels of caffeine were found in black tea, but higher levels of the catechins, especially epigallocatechin gallate (EGCG) were found in green teas. PMID:24206716
Determination of Sudan dyes in chili pepper powder by online solid-phase extraction with a butyl methacrylate monolithic column coupled to liquid chromatography with tandem mass spectrometry.
Liu, Yao; Wang, Man-Man; Ai, Lian-Feng; Zhang, Chang-Kun; Li, Xin; Wang, Xue-Sheng
A poly(butyl methacrylate-co-ethylene dimethacrylate) monolithic column was fabricated and used as a novel sorbent for online solid-phase extraction coupled to liquid chromatography with tandem mass spectrometry for the simultaneous determination of Sudan I-IV in chili pepper powder. The prepared columns were characterized by scanning electron microscopy, nitrogen adsorption-desorption, and pressure drop measurements. Online solid-phase extraction was performed on the synthesized monolithic column using 10 mM ammonium acetate solution as the loading solution with the aid of an online cleanup chromatography system. The desorption of Sudan I-IV was achieved with acetonitrile as the eluting solution at the flow rate of 0.5 mL/min. The extracted analytes were subsequently eluted into a C18 analytical column for chromatographic separation using a mixture of 10% acetonitrile/90% formic acid (0.5%) solution as the mobile phase. Under the optimized conditions, the developed method had linear range of 1.0-50 ?g/kg, a detection limit of 0.3Ā?g/kg, and a quantification limit of 1.0 ?g/kg for each analyte. The intraday and interday recoveries of Sudan I-IV in chili pepper powder samples ranged from 94.8 to 100.9% and 94.9 to 99.4%, respectively. The intraday and interday precision were between 3.37-7.01% and 5.01-7.68%, respectively. PMID:24723310
Compatibility of column inlet and adsorbent designs for processing of corn endosperm extract by expanded bed adsorption.
Menkhaus, Todd J; Glatz, Charles E
Corn has emerged as a viable host for expression of recombinant proteins; targeted expression to the endosperm has received particular attention. The protein extracts from corn endosperm differ from those of traditional hosts in regard to the nature of residual solids and extracted matrix contaminants. Each of these differences presents reasons for considering expanded bed adsorption for product capture and new considerations for limitations of the method. In this work three inlet-flow distribution devices (mesh, glass ballotini, and localized mixing) and six adsorbents with different physical (size and density), chemical (ligand), and base matrix properties were evaluated to determine conditions compatible with processing of crude corn endosperm extract by expanded bed adsorption. Of the inlet devices evaluated, the design with localized mixing at the inlet (as produced commercially by UpFront Chromatography A/S, Copenhagen, DK) allowed solids up to 550 microm into the column without clogging for all flow rates evaluated. A mesh at the inlet with size restriction of either 50 microm or 80 microm became clogged with very small corn particles (< 44 microm). When glass ballotini was used, large particles (550 microm) passed through for high flow rates (570 cm/h), but even small (< 44 microm) particles became trapped at a lower flow rate (180 cm/h). The physical and chemical properties of the resin determined whether solids could be eluted. The denser UpFront adsorbents allowed for complete elution of larger and more concentrated corn solids than the currently available Amersham Streamline adsorbents (Amersham Biosciences, Piscataway, NJ) as a result of the former's higher flow rate for the desired 2x expansion (570 cm/h for UpFront vs. 180 cm/h for Streamline). All corn solids < 162 microm eluted through nonderivatized UpFront resin. Larger corn solids began to accumulate due to their elevated sedimentation velocities. Feeds of < 44 microm solids at 0.45% and 2.0% dry weight successfully eluted through ion exchange adsorbents (DEAE and SP) from UpFront. However, significant accumulation occurred when the solids size increased to a feed of < 96 microm solids, thus indicating a weak interaction between corn solids and both forms of ion exchange ligands. Expanded beds operated with Streamline ion exchange adsorbents (DEAE and SP) did not allow full elution of corn solids of < 44 microm. A hyperdiffuse style EBA resin produced by Biosepra (Ciphergen Biosystems, Fremont, CA) with CM functionality showed a severe interaction with corn solids that collapsed the expanded bed and could not be eliminated with elevated flow rates or higher salt concentration. PMID:15281107
Axial focusing following low kinetic energy pulsed extraction from a miniature linear ion trap.
Dobson, Gareth S; Enke, Christie G
Using an axial focusing miniature linear ion trap with tubular end cap lenses (MLIT) we have investigated spatial focusing on ion ejection using low kinetic energy pulsed extraction methods. Ion packet widths focused to ca. 1 mm (in both the radial and axial planes) are produced following collisional cooling with helium buffer gas in an MLIT. Small axial and radial packet widths as well as application of DC extraction voltages allow different ion focusing techniques to be used on batch ion extraction. In particular, controlling the position of the space focus plane (commonly used in time-of-flight mass spectrometry) following low kinetic energy ( approximately 10 eV) ion ejection from an MLIT through the application of DC extraction voltages is illustrated. Prior to simultaneous ion ejection, induced axial ion oscillation through a change in the DC potential well shape is also shown to be useful for separating and controlling different mass/charge ion packet spatial distributions in the region of an orthogonal time-of-flight (o-TOF) push pulse. PMID:17663499
[Determination of streptomycin and dihydrostreptomycin residues in tomato paste by tandem dual solid phase extraction column-liquid chromatography-tandem mass spectrometry].
Gong, Zhiguo; Su, Min; Ji, Xincheng; Li, Shiyu; Wan, Yuping
The method was specifically developed for the simultaneous determination of streptomycin and dihydrostreptomycin residues in tomato paste by tandem dual solid phase extraction (SPE) column cleanup-liquid chromatography-tandem mass spectrometry. The residues were extracted from the samples with phosphate buffer solution (pH 4). The cleanup was performed by the way of dispersive solid phase extraction and tandem dual solid phase extraction column. The polar chromatographic column was used to complete the separation of the analytes under gradient elution and the analytes were detected in multiple reaction monitoring (MRM) mode via positive electrospray ionization (ESI +). The external standard calibration curves were used for the quantification. The linear ranges were from 0.01 to 0.2 mg/L with a good linear relationship (r > 0.999) for streptomycin and dihydrostreptomycin. The limit of quantification (LOQs) was 0.02 mg/kg for the both analytes. The recovery range was from 71% to 101% with the relative standard deviations (RSDs) between 2.3% and 15%. It was indicated that this method is accurate, easier, more sensitive, and has a better purification effect in the monitoring and analysis. The method is accurate and specific to monitor and analyze of streptomycin and dihydrostreptomycin residues in tomato paste and its products. PMID:22667088
Pulsed counter-current ultrasound-assisted extraction and characterization of polysaccharides from Boletus edulis.
You, Qinghong; Yin, Xiulian; Ji, Chaowen
Four methods for extracting polysaccharides from Boletus edulis, namely, hot-water extraction, ultrasonic clearer extraction, static probe ultrasonic extraction, and pulsed counter-current probe ultrasonic extraction (CCPUE), were studied. Results showed that CCPUE has the highest extraction efficiency among the methods studied. Under optimal CCPUE conditions, a B. edulis polysaccharide (BEP) yield of 8.21% was obtained. Three purified fractions, BEP-I, BEP-II, and BEP-III, were obtained through sequential purification by DEAE-52 and Sephadex G-75 chromatography. The average molecular weights of BEP-I, BEP-II, and BEP-III were 10,278, 23,761, and 42,736 Da, respectively. The polysaccharides were mainly composed of xylose, mannose, galactose, and glucose; of these, mannose contents were the highest. The antioxidant activities of the BEPs were further investigated by measurement of their ability to scavenge DPPH and hydroxyl radicals as well as their reducing power. The results indicated that the BEPs have good antioxidant activity. PMID:24299786
HPLC-MS-MS Determination of ZCZ-011, A Novel Pharmacological Tool for Investigation of the Cannabinoid Receptor in Mouse Brain Using Clean Screen FAStÖ Column Extraction.
Poklis, Justin L; Clay, Deborah J; Ignatowska-Jankowska, Bogna M; Zanato, Chiara; Ross, Ruth A; Greig, Iain R; Abdullah, Rehab A; Mustafa, Mohammed A; Lichtman, Aron H; Poklis, Alphonse
A high-performance liquid chromatography tandem mass spectrometry method was developed for the detection and quantification of 6-methyl-3-(2-nitro-1-(thiophen-2-yl)propyl)-2-phenyl-1H-indole (ZCZ-011) using 2-phenylindole as the internal standard (ISTD). ZCZ-011 was synthesized as a possible positive allosteric modulator with the CB1 cannabinoid receptor. The analytical method employs a rapid extraction technique using Clean Screen FAStÖ columns with a Positive Pressure Manifold. FAStÖ columns were originally developed for urine drug analysis but we have successfully adapted them to the extraction of brain tissue. Chromatographic separation was performed on a Restek Allure Biphenyl 5 Ą, 100 ū 3.2 mm column (Bellefonte, PA). The mobile phase consisted of 1:9 deionized water with 10 mmol ammonium acetate and 0.1% formic acid-methanol. The following transition ions (m/z) were monitored for ZCZ-011: 363 > 207 and 363 > 110 and for the ISTD: 194 > 165 and 194 > 89. The FAStÖ columns lowered and stabilized the ion suppression over the linear range of the assay (40-4,000 ng/g). The method was evaluated for recovery, ion suppression, accuracy/bias, intraday and interday precision, bench-top stability, freeze-thaw and post-preparative stability. The method was successfully applied to brain tissue from C57BL/6J mice that received intraperitoneal (i.p.) injections with 40 mg/kg of ZCZ-011 or vehicle. PMID:25737338
Gradient HPLC of samples extracted from the green microalga Botryococcus braunii using highly efficient columns packed with 2.6 ?m Kinetex-C?? core-shell particles.
Gritti, Fabrice; Perdu, Marie-AgnĶs; Guiochon, Georges
The analysis of the nonpolar extract of the cells of colonies of the green colonial microalgae Botryococcus braunii was performed by gradient HPLC. The growth of B. braunii was stressed by reducing its nitrogen nutrients by 90%, in order to enhance the production of nonpolar compounds. Highly efficient 4.6mm ū 100mm columns packed with 2.6 ?m Kinetex-C(18) core-shell particles (Phenomenex, Torrance, CA, USA) were used. The gradient mobile phase was a mixture of acetonitrile and water (70-97%, v/v). Its initial and final compositions during the gradient elution were chosen so that the retention factors of the last eluted compound at the inlet and outlet of the column were 15 and 1, respectively. The highest peak capacity was obtained by optimizing several experimental parameters, including the injected sample volume, the flow rate, and the column length. The highest resolution was obtained by connecting one 4.6 mm ū 150 mm and three 4.6mm ū 100mm columns (total length 45 cm). The optimum flow rate was 1.5 mL/min, which provided the minimum plate height for the most retained compounds, the optimum inlet pressure was 930 bar and the injected volume 2 ?L. The analysis time was then 14 min for a peak capacity of 121. The trends observed for the variation of the experimental peak capacity with the flow rate and the column length are in excellent agreement with theoretical predictions. PMID:22307155
Performance of programmed temperature vaporizer, pulsed splitless and on-column injection techniques in analysis of pesticide residues in plant matrices.
ZrostlĒkovß, J; Hajslovß, J; Godula, M; Mastovskß, K
A programmed temperature vaporizer (PTV) injection technique has been recently implemented in our laboratory. In present paper its performance is compared with other GC injection techniques commonly used in trace analysis of organic contaminants. Twenty-six pesticides representing different chemical classes were selected for the study. This group comprised compounds typically subjected to discrimination in the injection port of the gas chromatograph, e.g., polar organophosphorus pesticides and thermolabile carbamates. In the first set of experiments standards in pure solvent were injected into GC systems employing different types of injection, i.e., (i) on-column, (ii) pulsed splitless, (iii) PTV solvent split, (iv) PTV splitless, and the responses of analytes were compared. Discrimination of troublesome compounds was significantly decreased with the application of PTV solvent split injection. In the second set of experiments repetitive injections of purified wheat samples were performed, with aims to evaluate the long-term stability of responses, as well as matrix effects in different stages of system contamination for each injection technique. The tolerance of the GC system to co-injected matrix components was increased in the order: on-column
Simultaneous multi-mycotoxin determination in nutmeg by ultrasound-assisted solid-liquid extraction and immunoaffinity column clean-up coupled with liquid chromatography and on-line post-column photochemical derivatization-fluorescence detection.
Kong, Wei-Jun; Liu, Shu-Yu; Qiu, Feng; Xiao, Xiao-He; Yang, Mei-Hua
A simple and sensitive analytical method based on ultrasound-assisted solid-liquid extraction and immunoaffinity column clean-up coupled with high performance liquid chromatography and on-line post-column photochemical derivatization-fluorescence detection (USLE-IAC-HPLC-PCD-FLD) has been developed for simultaneous multi-mycotoxin determination of aflatoxins B1, B2, G1, G2 (AFB1, AFB2, AFG1, AFG2) and ochratoxin A (OTA) in 13 edible and medicinal nutmeg samples marketed in China. AFs and OTA were extracted from nutmeg samples by ultrasonication using a methanol?:?water (80?:?20, v/v) solution, followed by an IAC clean-up step. Different USL extraction conditions, pre-processing ways for nutmeg sample and clean-up columns for mycotoxins, as well as HPLC-PCD-FLD parameters (mobile phase, column temperature, elution procedure, excitation and emission wavelengths) were optimized. This method, which was appraised for analyzing nutmeg samples, showed satisfactory results with reference to limits of detection (LODs) (from 0.02 to 0.25 ?g kg(-1)), limits of quantification (LOQs) (from 0.06 to 0.8 ?g kg(-1)), linear ranges (up to 30 ng mL(-1) for AFB1, AFG1 and OTA and 9 ng mL(-1) for AFB2 and AFG2), intra- and inter-day variability (all <2%) and average recoveries (from 79.6 to 90.8% for AFs and from 93.6 to 97.3% for OTA, respectively). The results of the application of developed method in nutmeg samples have elucidated that four samples were detected with contamination of AFs and one with OTA. AFB1 was the most frequently found mycotoxin in 30.8% of nutmeg samples at contamination levels of 0.73-16.31 ?g kg(-1). At least two different mycotoxins were co-occurred in three samples, and three AFs were simultaneously detected in one sample. PMID:23486692
Novel Slow Extraction Scheme for Proton Accelerators Using Pulsed Dipole Correctors and Crystals
Shiltsev, V.; /Fermilab
Slow extraction of protons beams from circular accelerators is currently widely used for a variety of beam-based experiments. The method has some deficiencies including limited efficiency of extraction, radiation induced due to scattering on the electrostatic septa and limited beam pipe aperture, beam dynamics effects of space charge forces and magnet power supplies ripple. Here we present a novel slow extraction scheme employing a number of non-standard accelerator elements, such as Silicone crystal strips and pulsed stripline dipole correctors, and illustrate practicality of these examples at the 8 GeV proton Recycler Ring at Fermilab. The proposed method of non-resonant slow extraction of protons by bent crystals in combination with orbit fast deflectors shows great promise in simulations. We propose to initiate an R&D program in the Fermilab 8 GeV Recycler to address the key issues of the method: (a) feasibility of very short crystals - from few mm down to 0.2 mm; (b) their efficiency in the channelling and volume reflection regimes; (c) practical aspects of the fast deflectors.
The effect of dilution and the use of a post-extraction nucleic acid purification column on the accuracy, precision, and inhibition of environmental DNA samples
Mckee, Anna M.; Spear, Stephen F.; Pierson, Todd W.
Isolation of environmental DNA (eDNA) is an increasingly common method for detecting presence and assessing relative abundance of rare or elusive species in aquatic systems via the isolation of DNA from environmental samples and the amplification of species-specific sequences using quantitative PCR (qPCR). Co-extracted substances that inhibit qPCR can lead to inaccurate results and subsequent misinterpretation about a speciesÆ status in the tested system. We tested three treatments (5-fold and 10-fold dilutions, and spin-column purification) for reducing qPCR inhibition from 21 partially and fully inhibited eDNA samples collected from coastal plain wetlands and mountain headwater streams in the southeastern USA. All treatments reduced the concentration of DNA in the samples. However, column purified samples retained the greatest sensitivity. For stream samples, all three treatments effectively reduced qPCR inhibition. However, for wetland samples, the 5-fold dilution was less effective than other treatments. Quantitative PCR results for column purified samples were more precise than the 5-fold and 10-fold dilutions by 2.2ū and 3.7ū, respectively. Column purified samples consistently underestimated qPCR-based DNA concentrations by approximately 25%, whereas the directional bias in qPCR-based DNA concentration estimates differed between stream and wetland samples for both dilution treatments. While the directional bias of qPCR-based DNA concentration estimates differed among treatments and locations, the magnitude of inaccuracy did not. Our results suggest that 10-fold dilution and column purification effectively reduce qPCR inhibition in mountain headwater stream and coastal plain wetland eDNA samples, and if applied to all samples in a study, column purification may provide the most accurate relative qPCR-based DNA concentrations estimates while retaining the greatest assay sensitivity.
Rapid simultaneous determination of eperisone, tolperisone, and tizanidine in human serum by using a MonoSpin« C18 extraction column and liquid chromatography/tandem mass spectrometry.
Miura, Naoya; Saito, Takeshi; Taira, Takayuki; Yamagiwa, Takeshi; Morita, Sein; Inokuchi, Sadaki
A method was developed for rapid toxicological analysis of eperisone, tolperisone, and tizanidine in human serum using a MonoSpin« C18 extraction column and LC/MS/MS. The method was validated for LOD, linearity, precision, and extraction recovery. This method was rapid with an LOD of 0.5 ng/mL, linearity range 1-500.0 ng/mL (r2 = 0.999), and RSD value below 14.6%. Extraction recovery from the sample was greater than 98.6, 98.8, and 88.5% for eperisone, tolperisone, and tizanidine, respectively. Results showed that combination of the MonoSpin C18 extraction column and LC/MS/MS is a simple and rapid method for the analysis of these three analytes, and a method is described for simultaneous quantitative determination of the analytes in human serum by LC/MSIMS. This method was used to determine the serum levels of eperisone in a patient with eperisone poisoning, and could be successfully applied for screening analyses in clinical cases other than poisoning. PMID:25632432
Development and validation of an HPLC method for determination of Amikacin in water samples by solid phase extraction and pre-column derivatization.
Li, Deguang; He, Shun; Deng, Yufang; Ding, Guanglong; Ni, Hanwen; Cao, Yongsong
This work presents a rapid and sensitive high performance liquid chromatography method for the determination of amikacin in water samples with solid phase extraction and pre-column derivatization. Amikacin residue was extracted from water samples with solid phase extraction cartridge. Then the extraction solution was derivatized with 4-chloro-3,5-dinitrobenzotrifluoride in the presence of triethylamine at 70░C in 20 min. The amikacin derivative was separated on a C18 column and detected by application of UV detection at 238 nm. The limit of detection is 0.2 ?g/L with a signal-to-noise ratio of 3 and linearity is established over the concentration range from 0 to 500.0 ?g/L. Recoveries of the amikacin in three types of water samples are from 87.5 % to 99.6 % and RSDs are 2.1 %-4.5 %. This method can be used for the quantification of amikacin residues in water samples. PMID:24663966
A molecularly imprinted organic-inorganic hybrid monolithic column for the selective extraction and HPLC determination of isoprocarb residues in rice.
Yang, Ting; Ma, Chao; Chen, Huaixia; Zhang, Yajie; Dang, Xueping; Huang, Jianlin
An IPC-imprinted (IPC is isoprocarb) poly(methacrylic acid)/SiO2 hybrid monolithic column was prepared and applied for the recognition of the template. The hybrid monolithic column was synthesized in a micropipette tip using methyltrimethoxysilane as the inorganic precursor, 3-(methacryloxy)propyltrimethoxysilane as the coupling agent, and ethylene glycol dimethacrylate as the cross-linker. The synthesis conditions, including the porogenic solvent, coupling agent, volume ratio of the inorganic alcoholysate and organic part, were optimized. The prepared monolithic column was characterized by SEM and FTIR spectroscopy. A simple, rapid, and sensitive method for the determination of IPC in rice using the imprinted monolithic column microextraction combined with HPLC was developed. Several parameters affecting the sample pretreatment were investigated, including the eluent, washing solution, and loading sample volume. The linearity of the calibration curve was observed in the range of 9.0-1000 ?g/kg for IPC in rice with the correlation coefficient (r2) of 0.9983. The LOD was 3.0 ?g/kg (S/N = 3). The assay gave recovery values ranging from 91 to 107%. The proposed method has been successfully applied for the selective extraction and sensitive determination of IPC in rice and a satisfactory result was obtained. PMID:24376214
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On-line hyphenation of solid-phase extraction to chromatographic separation of sulfonamides with fused-core columns in sequential injection chromatography.
Batista, Alex D; ChocholouÜ, Petr; SatĒnsk², Dalibor; Solich, Petr; Rocha, Fßbio R P
On-line sample pretreatment (clean-up and analyte preconcentration) is for the first time coupled to sequential injection chromatography. The approach combines anion-exchange solid-phase extraction and the highly effective pentafluorophenylpropyl (F5) fused-core particle column for separation of eight sulfonamide antibiotics with similar structures (sulfathiazole, sulfanilamide, sulfacetamide, sulfadiazine, sulfamerazine, sulfadimidine, sulfamethoxazole and sulfadimethoxine). The stationary phase was selected after a critical comparison of the performance achieved by three fused-core reversed phase columns (Ascentis(«) Express RP-Amide, Phenyl-Hexyl, and F5) and two monolithic columns (Chromolith(«) High Resolution RP-18 and CN). Acetonitrile and acetate buffer pH 5.0 at 0.60 mL min(-1) were used as mobile phase to perform the separations before spectrophotometric detection. The first mobile phase was successfully used as eluent from SPE column ensuring transfer of a narrow zone to the chromatographic column. Enrichment factors up to 39.2 were achieved with a 500 ĄL sample volume. The developed procedure showed analysis time <10.5 min, resolutions >1.83 with peak symmetry ?1.52, LODs between 4.9 and 27 Ąg L(-1), linear response ranges from 30.0 to 1000.0 Ąg L(-1) (r(2)>0.996) and RSDs of peak heights <2.9% (n=6) at a 100 Ąg L(-1) level and enabled the screening control of freshwater samples contaminated at the 100 Ąg L(-1) level. The proposed approach expanded the analytical potentiality of SIC and avoided the time-consuming batch sample pretreatment step, thus minimizing risks of sample contamination and analyte losses. PMID:25435240
Preconcentration of trace manganese from natural waters by complexation with dithiocarbamate and adsorption onto C 18 -solid phase extraction column for neutron activation analysis
S. B. Sarmani; M. P. Abdullah; A. M. Bobaker
A method was developed for the preconcentration and separation of trace manganese from natural water samples by complexation\\u000a with dithiocarbamate followed by adsorption onto C18-solid phase extraction column prior to irradiation. The Mn recovery was better than 99.8% without inteference from iron(III)\\u000a at 5 mg.l-1, copper(II), zinc(II), aluminum(III) and cobalt(II) at 0.5 mg.l-1 and sodium(I), potassium(I), magnesium(II) and calcium(II) at
Accurate Extraction of Electrostatic Force by a Voltage-Pulse Force Spectroscopy
NASA Astrophysics Data System (ADS)
Inami, Eiichi; Sugimoto, Yoshiaki
The classification of interaction forces between two approaching bodies is important in a wide range of research fields. Here, we propose a method to unambiguously extract the electrostatic force (Fele ), which is one of the most significant forces. This method is based on the measurement of the energy dissipation under applied voltage pulse between an atomic force microscopy (AFM) tip and sample. It allowed us to obtain Fele as a function of the tip-sample distance and voltage including the distance-independent part, to which conventional AFM is insensitive. The obtained Fele curves nicely fit the analytical model, enabling estimation of the geometry of the tip. The distance-dependent contact potential difference could also be correctly obtained by the measured Fele, opening an alternative route to quantitative Kelvin probe force microscopy.
Acaricidal activity of petroleum ether extract of neem (Azadirachta indica) oil and its four fractions separated by column chromatography against Sarcoptes scabiei var. cuniculi larvae in vitro.
Deng, Yunxia; Shi, Dongxia; Yin, Zhongqiong; Guo, Jianhong; Jia, Renyong; Xu, Jiao; Song, Xu; Lv, Cheng; Fan, Qiaojia; Liang, Xiaoxia; Shi, Fei; Ye, Gang; Zhang, Wei
The petroleum ether extract of neem oil and its four fractions separated by column chromatography was diluted at different concentrations with liquid paraffin. The acaricidal bioassay was conducted using a dipping method. The results indicated that the median lethal concentration (LC50) of the petroleum ether extract (at the concentration of 500.0ml/l) was 70.9ml/l, 24h after treatment. At concentrations of 500.0, 250.0, 125.0, 62.5 and 31.2ml/l, the median lethal times (LT50) of the petroleum ether extract were 8.7, 8.8, 10.8, 11.5 and 13.1h, respectively. Thin-layer chromatography (TLC) showed that the petroleum ether extract of neem oil separated into four fractions (F1-F4). Acaricidal activity of 68.3% and 100.0% in the F2 and F4 was confirmed. These results suggest that petroleum ether extracts of neem oil and its four fractions possess useful acaricidal activity in vitro. PMID:22349080
Propagation of a surface microwave along the afterglow plasma column of a high-current pulsed discharge
Sergeichev, K. F.; Karfidov, D. M. [Russian Academy of Sciences, Prokhorov General Physics Institute (Russian Federation)
It is demonstrated experimentally that the lifetime of the afterglow plasma of a high-current pulsed discharge in a dielectric tube filled with a mixture of argon with saturated mercury vapor is longer than 1 ms. Such a long lifetime, during which the electron density decreases from 10{sup 14} to 10{sup 12} cm{sup -3}, is explained by the chemi-ionization of mercury vapor by long-lived metastable argon atoms. During this time, the afterglow plasma can serve as a microwave waveguide for a weakly damped low-noise E{sub 0}-type axisymmetric surface mode, which allows one to use it for transmission of signals in the centimeter wavelength range.
On-line SPE-UHPLC method using fused core columns for extraction and separation of nine illegal dyes in chilli-containing spices.
Khalikova, Maria A; SatĒnsk², Dalibor; Smidrkalovß, Tereza; Solich, Petr
The presented work describes the development of a simple, fast and effective on-line SPE-UHPLC-UV/vis method using fused core particle columns for extraction, separation and quantitative analysis of the nine illegal dyes, most frequently found in chilli-containing spices. The red dyes Sudan I-IV, Sudan Red 7B, Sudan Red G, Sudan Orange G, Para Red, and Methyl Red were separated and analyzed in less than 9 min without labor-consuming pretreatment procedure. The chromatographic separation was performed on Ascentis Express RP-Amide column with gradient elution using mixture of acetonitrile and water, as a mobile phase at a flow rate of 1.0 mL min(-1) and 55░C of temperature. As SPE sorbent for cleanup and pre-concentration of illegal dyes short guard fused core column Ascentis Express F5 was used. The applicability of proposed method was proven for three different chilli-containing commercial samples. Recoveries for all compounds were between 90% and 108% and relative standard deviation ranged from 1% to 4% for within- and from 2% to 6% for between-day. Limits of detection showed lower values than required by European Union regulations and were in the range of 3.3-10.3 Ąg L(-1) for standard solutions, 5.6-235.6 Ąg kg(-1) for chilli-containing spices. PMID:25159432
[Determination of ochratoxin A in human urine by HPLC-FLD after cleaned-up by molecularly imprinted polymer solid phase extraction column].
Xie, Li-Wei; Zhao, Xiang-Sheng; Kong, Wei-Jun; Wang, Yu-Ting; Hu, Yi-Chen; Ou-Yang, Zhen; Yang, Mei-Hua
A method was developed for the determination of ochratoxin A (OTA) in human urine by HPLC-FLD after molecularly imprinted polymer solid phase extraction (MIP-SPE) column. After the pH being adjusted to 2.5 with 0.1 mol x L(-1) HC1, sample was cleaned up with MIP-SPE column for ochratoxin A, the analyte was analyzed by high performance liquid chromatography coupled with fluorescence detection (HPLC-FLD), and finally all the positive results were confirmed by LC-MS/MS. Recoveries from urine samples spiked with OTA at levels ranging from 2 to 20 ng x mL(-1) were 90.6%-101.9%, and RSDs were 0.1%-1.6%. Sixty-five volunteers living in Beijing took part in the study, of which 5 were found containing OTA in their urine and the highest value was 0.091 ng x mL(-1). The MIP-SPE column was firstly applied to purify and concentrate OTA in human urine, this method is simple, rapid and reliable and can be used to determine the contents of OTA in human urine. PMID:24974471
The Perils of Pathogen Discovery: Origin of a Novel Parvovirus-Like Hybrid Genome Traced to Nucleic Acid Extraction Spin Columns
Naccache, Samia N.; Greninger, Alexander L.; Lee, Deanna; Coffey, Lark L.; Phan, Tung; Rein-Weston, Annie; Aronsohn, Andrew; Hackett, John; Delwart, Eric L.
Next-generation sequencing was used for discovery and de novo assembly of a novel, highly divergent DNA virus at the interface between the Parvoviridae and Circoviridae. The virus, provisionally named parvovirus-like hybrid virus (PHV), is nearly identical by sequence to another DNA virus, NIH-CQV, previously detected in Chinese patients with seronegative (non-A-E) hepatitis. Although we initially detected PHV in a wide range of clinical samples, with all strains sharing ?99% nucleotide and amino acid identity with each other and with NIH-CQV, the exact origin of the virus was eventually traced to contaminated silica-binding spin columns used for nucleic acid extraction. Definitive confirmation of the origin of PHV, and presumably NIH-CQV, was obtained by in-depth analyses of water eluted through contaminated spin columns. Analysis of environmental metagenome libraries detected PHV sequences in coastal marine waters of North America, suggesting that a potential association between PHV and diatoms (algae) that generate the silica matrix used in the spin columns may have resulted in inadvertent viral contamination during manufacture. The confirmation of PHV/NIH-CQV as laboratory reagent contaminants and not bona fide infectious agents of humans underscores the rigorous approach needed to establish the validity of new viral genomes discovered by next-generation sequencing. PMID:24027301
Methods of analysis by the U.S. Geological Survey National Water Quality Laboratory; determination of pesticides in water by C-18 solid-phase extraction and capillary-column gas chromatography/mass spectrometry with selected-ion monitoring
Zaugg, Steven D.; Sandstrom, Mark W.; Smith, Steven G.; Fehlberg, Kevin M.
A method for the isolation of 41 pesticides and pesticide metabolites in natural-water samples using C-18 solid-phase extraction and determination by capillary-column gas chromatography/mass spectrometry with selected-ion monitoring is described. Water samples are filtered to remove suspended particulate matter and then are pumped through disposable solid-phase extraction columns containing octadecyl-bonded porous silica to extract the pesticides. The columns are dried using carbon dioxide or nitrogen gas, and adsorbed pesticides are removed from the columns by elution with 3.0 milliliters of hexane-isopropanol (3:1). Extracted pesticides are determined by capillary- column gas chromatography/mass spectrometry with selected-ion monitoring of three characteristic ions. The upper concentration limit is 4 micrograms per liter (g/L) for most pesticides, with the exception of widely used corn herbicides--atrazine, alachlor, cyanazine, and metolachlor--which have upper concentration limits of 20 g/L. Single- operator method detection limits in reagent-water samples range from 0.001 to 0.018 g/L. Average short-term single-operator precision in reagent- water samples is 7 percent at the 0.1- and 1.0-g/L levels and 8 percent at the 0.01-g/L level. Mean recoveries in reagent-water samples are 73 percent at the 0.1- and 1.0-g/L levels and 83 percent at the 0.01-g/L level. The estimated holding time for pesticides after extraction on the solid-phase extraction columns was 7 days. An optional on-site extraction procedure allows for samples to be collected and processed at remote sites where it is difficult to ship samples to the laboratory within the recommended pre-extraction holding time.
Manual for the thermal and hydraulic design of direct contact spray columns for use in extracting heat from geothermal brines
Jacobs, H.R.
This report outlines the current methods being used in the thermal and hydraulic design of spray column type, direct contact heat exchangers. It provides appropriate referenced equations for both preliminary design and detailed performance. The design methods are primarily empirical and are applicable for us in the design of such units for geothermal application and for application with solar ponds. Methods for design, for both preheater and boiler sections of the primary heat exchangers, for direct contact binary powers plants are included. 23 refs., 8 figs.
Determination of lignin in marine sediment using alkaline cupric oxide oxidation-solid phase extraction-on-column derivatization-gas chromatography
NASA Astrophysics Data System (ADS)
Zhang, Ting; Li, Xianguo; Sun, Shuwen; Lan, Haiqing; Du, Peirui; Wang, Min
Lignin serves as one of the most important molecular fossils for tracing Terrestrial Organic Matters (TOMs) in marine environment. Extraction and derivatization of lignin oxidation products (LOPs) are crucial for accurate quantification of lignin in marine sediment. Here we report a modification of the conventional alkaline cupric oxide (CuO) oxidation method, the modification consisting in a solid phase extraction (SPE) and a novel on-column derivatization being employed for better efficiency and reproducibility. In spiking blanks, recoveries with SPE for the LOPs are between 77.84% and 99.57% with relative standard deviations (RSDs) ranging from 0.57% to 8.04% ( n=3), while those with traditional liquid-liquid extraction (LLE) are from 44.52% to 86.16% with RSDs being from 0.53% to 13.14% ( n=3). Moreover, the reproducibility is greatly improved with SPE, with less solvent consumption and shorter processing time. The average efficiency of on-column derivatization for LOPs is 100.8% ▒ 0.68%, which is significantly higher than those of in-vial or in-syringe derivatization, thus resulting in still less consumption of derivatizing reagents. Lignin in the surface sediments sampled from the south of Yangtze River estuary, China, was determined with the established method. Recoveries of 72.66% to 85.99% with standard deviation less than 0.01mg/10g dry weight are obtained except for p-hydroxyben-zaldehyde. The lignin content ?8 (produced from 10 g dry sediment) in the research area is between 0.231 and 0.587 mg. S/V and C/V ratios (1.028 ▒ 0.433 and 0.192 ▒ 0.066, respectively) indicate that the TOMs in this region are originated from a mixture of woody and nonwoody angiosperm plants; the high values of (Ad/Al)v suggest that the TOMs has been highly degraded.
The effect of whitecaps and foam on wind speed extraction with a pulse limited radar altimeter
NASA Astrophysics Data System (ADS)
Gairola, R. M.; Pandey, P. C.
The effect of whitecaps and foam on wind speed extraction with a pulse limited radar altimeter has been studied using a specular point model. By modelling foam and water as a two-layer media, we have investigated the changes in reflectivity as a function of thickness using electro-magnetic field theory. Our analysis indicated a change of reflectivity from a value of 0.617 at 13.9 GHz normal incidence to a value of 0.10 for a foam thickness of less than 1 cm. The values of reflectivity computed from a two-layer model compared fairly well with these derived using an emissivity model. The modified specular point model gave an improved relationship between ?o and wind speed in comparison to BrownÆs model. The Seasat altimeterÆs data analysis over the Arabian sea and the Bay of Bengal gave an rms difference of 2.2 m/sec in wind speed retrieval using the present modified model and BrownÆs model.
[Monolith column solid-phase extraction coupled with high performance liquid chromatography in online mode for the determination of forchlorfenuron in fruits].
Luo, Weiqiang; Xiao, Xiaohu; Du, Zhuo; Li, Gongke
A novel method based on the monolithic column solid-phase extraction (SPE) coupled with high performance liquid chromatography in online mode was developed for the determination of trace forchlorfenuron in fruits. The enrichment factor of SPE for forchlorfenuron was 214. The method was fully validated. It showed a linear range of 0.01-50.00 microg/L and a limit of detection of 25 ng/L, with the relative standard deviation (RSD) of 3.9%. The proposed method was successfully applied for the determination of forchlorfenuron in grape, kiwifruit and watermelon samples, with the recoveries of 87.0%-120.7% and the RSDs of 0.6%-9.2%. This online method was proved to be selective, sensitive and convenient for the determination of trace forchlorfenuron in complex samples. PMID:25069331
Solid phase micro extraction coupled with on-column GC/ECD for the post-blast analysis of organic explosives.
Calderara, Stķphane; Gardebas, Dominique; Martinez, Fabienne
Gas chromatographic analysis with electron capture detection is very sensitive to post-blast residues and useful for the determination of organic explosive molecules. But many compounds extracted from the matrices may interfere with the explosives. Using SPME, most interfering compounds are eliminated so the identification is easier. Another advantage of the technique is a low limit of detection. In this study, four different SPME fibers were tested to analyze the most common encountered organic explosives including nitro aromatics, nitramines and nitro-esters. Different parameters were tested (desorption time, agitation, ...) and a special device has been created to optimize the agitation. Direct desorption effect of the SPME fiber on the column compared to normal split-splitless injection is shown. In this way, the degradation of the most sensitive molecules is decreased. An application to a real case is also described in this paper. PMID:14550606
NSDL National Science Digital Library
John Lennox
This is an exercise about Winogradsky Columns with emphasis placed on the formation and properties of microbial biofilms. It includes background reference material, a field/lab exercise, and several applications. Applications include methods for sampling column layers and a description of how to measure the electro-chemical gradient that develops within the column. Scientific illustrations and images are included as visual references.
Modelling of the positive column of a medium-pressure Cs-Xe dc discharge affected by a millimetre wave pulse
NASA Astrophysics Data System (ADS)
Gitlin, M. S.; Epstein, I. L.; Lebedev, Yu A.
A time-dependent zero-dimensional kinetic model of the positive column (PC) of a medium-pressure Cs-Xe dc discharge was used to gain a better insight into the physical basics of plasma techniques for imaging and control of millimetre wave (MMW) beams. The model allowed one to study the effect of MMWs on the kinetic and electrical characteristics of the spatially homogeneous PC of a Cs-Xe dc discharge. We computed the PC plasma parameters for 30 Torr and 45 Torr xenon and discharge current densities of about 0.1 A cm-2. First, the dependences of the PC parameters on caesium density were calculated in the case of no MMWs incident on the PC plasma. Then, the temporal evolution of the parameters of the PC plasma affected by a long watt-scale Ka-band MMW pulse was modelled for caesium densities of about 3 ū 1012 and 5 ū 1012 cm-3. The calculations showed that the electron temperature in the PC plasma attained quasisteady-state values for about 1 Ąs after the beginning of the MMW pulse. The electron temperature rises by 0.2-0.3 eV as the MMW intensity increases from 0 to 1 W cm-2. The rise time of the electron density decreased with an increase in the MMW intensity W from about 1 ms for W = 0.15 W cm-2 to tens of microseconds for W > 1.5 W cm-2. The steady-state values of the electron density increased in proportion to W, if W < 0.5 W cm-2. They were approximately constant for 0.5 < W < 2 W cm-2 due to the nearly full ionization of caesium atoms in the PC plasma. Efficient xenon excitation and ionization for W > 3 W cm-2 could be a cause of the microwave breakdown of the homogeneous PC plasma. The results of the modelling are in good agreement with the published experimental data.
Development of an Automated Column Solid-Phase Extraction Cleanup of QuEChERS Extracts, Using a Zirconia-Based Sorbent, for Pesticide Residue Analyses by LC-MS/MS.
Morris, Bruce D; Schriner, Richard B
A new, automated, high-throughput, mini-column solid-phase extraction (c-SPE) cleanup method for QuEChERS extracts was developed, using a robotic X-Y-Z instrument autosampler, for analysis of pesticide residues in fruits and vegetables by LC-MS/MS. Removal of avocado matrix and recoveries of 263 pesticides and metabolites were studied, using various stationary phase mixtures, including zirconia-based sorbents, and elution with acetonitrile. These experiments allowed selection of a sorbent mixture consisting of zirconia, C18, and carbon-coated silica, that effectively retained avocado matrix but also retained 53 pesticides with <70% recoveries. Addition of MeOH to the elution solvent improved pesticide recoveries from zirconia, as did citrate ions in CEN QuEChERS extracts. Finally, formate buffer in acetonitrile/MeOH (1:1) was required to give >70% recoveries of all 263 pesticides. Analysis of avocado extracts by LC-Q-Orbitrap-MS showed that the method developed was removing >90% of di- and triacylglycerols. The method was validated for 269 pesticides (including homologues and metabolites) in avocado and citrus. Spike recoveries were within 70-120% and 20% RSD for 243 of these analytes in avocado and 254 in citrus, when calibrated against solvent-only standards, indicating effective matrix removal and minimal electrospray ionization suppression. PMID:25702899
Extracting Oxygen from Lunar Simulant Using a Transparent Furnace Pulsed Fluidized Bed
NASA Technical Reports Server (NTRS)
Oryshchyn, L.; Paz, A.; Lee, K.; Reddington, M.
In the event that humans return to the moon, utilizing the local materials will be beneficial for extended stays. Rather than transporting resources, such as oxygen, from Earth, NASA is investigating methods of extracting it from lunar regolith. One promising process is hydrogen reduction. In the hydrogen reduction process, lunar regolith is heated to 1000 C in the presence of hydrogen. The iron oxide (Fe-O) bonds, found in lunar material, are broken and the hydrogen attracts the oxygen to produce water vapor [Allen et al., 1996]. FeO + H2 (right arrow) Fe +H2O. The water vapor is then captured, cleaned, and electrolyzed. The hydrogen is recycled back to the reduction process and the oxygen is stored until consumed by an end user (propulsion, life support, etc.). To obtain a good oxygen yield, the majority of lunar regolith must be exposed to the hydrogen gas and have a high rate of heat transfer from heat source to particle. This is achieved with good solids mixing via fluidization or mechanical agitation. In Generation II of the ROxygen program, the ROxygen Team at Johnson Space Center (JSC) investigated the feasibility of gas only pulsed fluidization as the only means to mix synthetic lunar regolith (simulant) at high temperatures. Fluidized beds have been used in industry to effectively process powders for decades. They consist of gas flowing upward through a bed of particles. The stirring action continuously moves the grains around to achieve uniform mixing of gas, solids, and heat [Geldart, 1986]. A transparent furnace unit was developed by Thoughventions Unlimited LLC (TvU) to aid in the qualitative observation of the fluidization behavior at high temperatures. Multipoint thermocouples and pressure sensors provided quantitative information regarding the quality of mixing. The water produced was measured using humidity sensors and captured using a NASA designed and built condenser. Once the simulant was processed, pneumatically transporting the 'hot' simulant out of the furnace was investigated.
Determination of Wastewater Compounds in Whole Water by Continuous Liquid-Liquid Extraction and Capillary-Column Gas Chromatography/Mass Spectrometry
Zaugg, Steven D.; Smith, Steven G.; Schroeder, Michael P.
A method for the determination of 69 compounds typically found in domestic and industrial wastewater is described. The method was developed in response to increasing concern over the impact of endocrine-disrupting chemicals on aquatic organisms in wastewater. This method also is useful for evaluating the effects of combined sanitary and storm-sewer overflow on the water quality of urban streams. The method focuses on the determination of compounds that are indicators of wastewater or have endocrine-disrupting potential. These compounds include the alkylphenol ethoxylate nonionic surfactants, food additives, fragrances, antioxidants, flame retardants, plasticizers, industrial solvents, disinfectants, fecal sterols, polycyclic aromatic hydrocarbons, and high-use domestic pesticides. Wastewater compounds in whole-water samples were extracted using continuous liquid-liquid extractors and methylene chloride solvent, and then determined by capillary-column gas chromatography/mass spectrometry. Recoveries in reagent-water samples fortified at 0.5 microgram per liter averaged 72 percent ? 8 percent relative standard deviation. The concentration of 21 compounds is always reported as estimated because method recovery was less than 60 percent, variability was greater than 25 percent relative standard deviation, or standard reference compounds were prepared from technical mixtures. Initial method detection limits averaged 0.18 microgram per liter. Samples were preserved by adding 60 grams of sodium chloride and stored at 4 degrees Celsius. The laboratory established a sample holding-time limit prior to sample extraction of 14 days from the date of collection.
[A novel solid phase extraction column combined with ultra performance liquid chromatography/tandem mass spectrometry for selective enrichment and determination of clenbuterol in pork].
Meng, Wenying; Guo, Zhimou; Shen, Weijian; Shen, Chongyu; Wu, Bin; Liu, Yanming; Zhang, Feifang; Liang, Xinmiao
A simple and efficient method based on a novel solid phase extraction (SPE) cartridge and ultra performance liquid chromatography-tandem mass spectrometry (UPLC-MS/ MS) was developed for the determination of clenbuterol residue in pork. The minced pork sample was ultrasonically extracted by 5% (v/v) perchloric acid and centrifuged at 10 000 r/min for 15 min, then the supernatant was purified by an SMCX cartridge, which is a novel SPE column based on homemade silica matrix with two mixed modes of reversed-phase and strong cation exchange, for the selective enrichment and purification of the analyte. The linear range of the method was 0.25 - 50 microg/kg with a correlation coefficient of 0.998 2. The average recoveries ranged from 62.2% to 72.0% at the three spiked levels of 1.25, 12.5 and 50 microg/kg with the relative standard deviations (RSDs) between 4.2% and 6.1%. The limit of detection (S/N = 3) was 0.05 microg/kg. The method is simple, fast and can be extended to enrich and determine beta-agonist drugs. PMID:22679827
Multiresidue pesticide analysis of botanical dietary supplements using salt-out acetonitrile extraction, solid-phase extraction cleanup column, and gas chromatography-triple quadrupole mass spectrometry.
Hayward, Douglas G; Wong, Jon W; Shi, Feng; Zhang, Kai; Lee, Nathaniel S; DiBenedetto, Alex L; Hengel, Mathew J
Dietary supplements form an increasing part of the American diet, yet broadly applicable multiresidue pesticide methods have not been evaluated for many of these supplements. A method for the analysis of 310 pesticides, isomers, and pesticide metabolites in dried botanical dietary supplements has been developed and validated. Sample preparation involved acetonitrile:water added to the botanical along with anhydrous magnesium sulfate and sodium chloride for extraction, followed by cleanup with solid-phase extraction using a tandem cartridge consisting of graphitized carbon black (GCB) and primary-secondary amine sorbent (PSA). Pesticides were measured by gas chromatography-tandem mass spectrometry. Accuracy and precision were evaluated through fortifications of 24 botanicals at 10, 25, 100, and 500 ?g/kg. Mean pesticide recoveries and relative standard deviations (RSDs) for all botanicals were 97%, 91%, 90%, and 90% and 15%, 10%, 8%, and 6% at 10, 25, 100, and 500 ?g/kg, respectively. The method was applied to 21 incurred botanicals. Quinoxyfen was measured in hops (100-620 ?g/kg). Tetraconazole (48 ?g/kg), tetramethrin (15 ?g/kg), methamidophos (50 ?g/kg), and chlorpyrifos (93 ?g/kg) were measured in licorice, mallow, tea, and tribulus, respectively. Quintozene, its metabolites and contaminants (pentachloroaniline, pentachlorobenzene, pentachloroanisole, and pentachlorothioanisole and hexachlorobenzene and tecnazene, respectively), with hexachlorocyclohexanes and DDT were identified in ginseng sources along with azoxystrobin, diazinon, and dimethomorph between 0.7 and 2800 ?g/kg. Validation with these botanicals demonstrated the extent of this method's applicability for screening 310 pesticides in a wide array of botanical dietary supplements. PMID:23534560
Rapid separation of microbial lipids using solid phase extraction columns 1 Disclaimer: mention of trade names or commercial products does not constitute endorsement or recommendation for use by the US Environmental Protection Agency. 1
Holly C Pinkart; Richard Devereux; Peter J Chapman
A method was developed to rapidly separate lipid classes commonly found in microorganisms. The method is based on the use of aminopropyl solid phase extraction columns to separate polyhydroxyalkanoates (PHA), phospholipids, sterols, triglycerides, diglycerides, monoglycerides, and steryl esters. Recoveries of all lipid classes, with the exception of PHA and sterols, ranged from 91% to greater than 99%. PHA were recovered
Determination of Cd, Co, Cr, Cu, Fe, Mn, Ni and Pb in natural waters, alkali and alkaline earth salts by electrothermal atomic absorption spectrometry after preconcentration by column solid phase extraction
Irina Karadjova
Methods are described for the determination of trace and ultra trace amounts of Cd, Co, Cr, Cu, Fe, Mn, Ni and Pb in natural waters, alkali and alkaline earth salts. Separation and preconcentration of trace metals is achieved by a column solid phase extraction procedure using silica gel modified with derivatives of dithiocarbamates Ś Na-DDTC (sodium diethyldithio-carbamate and HMDTC (ammonium
Extraction of pulse repetition intervals from sperm whale click trains for ocean acoustic data mining.
Zaugg, Serge; van der Schaar, Mike; Houķgnigan, Ludwig; Andrķ, Michel
The analysis of acoustic data from the ocean is a valuable tool to study free ranging cetaceans and anthropogenic noise. Due to the typically large volume of acquired data, there is a demand for automated analysis techniques. Many cetaceans produce acoustic pulses (echolocation clicks) with a pulse repetition interval (PRI) remaining nearly constant over several pulses. Analyzing these pulse trains is challenging because they are often interleaved. This article presents an algorithm that estimates a pulse's PRI with respect to neighboring pulses. It includes a deinterleaving step that operates via a spectral dissimilarity metric. The sperm whale (SW) produces trains with PRIs between 0.5 and 2 s. As a validation, the algorithm was used for the PRI-based identification of SW click trains with data from the NEMO-ONDE observatory that contained other pulsed sounds, mainly from ship propellers. Separation of files containing SW clicks with a medium and high signal to noise ratio from files containing other pulsed sounds gave an area under the receiver operating characteristic curve value of 0.96. This study demonstrates that PRI can be used for the automated identification of SW clicks and that deinterleaving via spectral dissimilarity contributes to algorithm performance. PMID:23363108
Methods of analysis by the U.S. Geological Survey National Water Quality Laboratory; determination of semivolatile organic compounds in bottom sediment by solvent extraction, gel permeation chromatographic fractionation, and capillary-column gas chromatography/mass spectrometry
Furlong, E.T.; Vaught, D.G.; Merten, L.M.; Foreman, W.T.; Gates, P.M.
A method for the determination of 79 semivolatile organic compounds (SOCs) and 4 surrogate compounds in soils and bottom sediment is described. The SOCs are extracted from bottom sediment by solvent extraction, followed by partial isolation using high-performance gel permeation chromatography (GPC). The SOCs then are qualitatively identified and quantitative concentrations determined by capillary-column gas chromatography/mass spectrometry (GC/MS). This method also is designed for an optional simultaneous isolation of polychlorinated biphenyls (PCBs) and organochlorine (OC) insecticides, including toxaphene. When OCs and PCBs are determined, an additional alumina- over-silica column chromatography step follows GPC cleanup, and quantitation is by dual capillary- column gas chromatography with electron-capture detection (GC/ECD). Bottom-sediment samples are centrifuged to remove excess water and extracted overnight with dichloromethane. The extract is concentrated, centrifuged, and then filtered through a 0.2-micrometer polytetrafluoro-ethylene syringe filter. Two aliquots of the sample extract then are quantitatively injected onto two polystyrene- divinylbenzene GPC columns connected in series. The SOCs are eluted with dichloromethane, a fraction containing the SOCs is collected, and some coextracted interferences, including elemental sulfur, are separated and discarded. The SOC-containing GPC fraction then is analyzed by GC/MS. When desired, a second aliquot from GPC is further processed for OCs and PCBs by combined alumina-over-silica column chromatography. The two fractions produced in this cleanup then are analyzed by GC/ECD. This report fully describes and is limited to the determination of SOCs by GC/MS.
Plasma assay of salbutamol by means of high-performance liquid chromatography with amperometric determination using a loop column for injection of plasma extracts. Application to the evaluation of subcutaneous administration of salbutamol.
Tamisier-Karolak, L; Delhotal-Landes, B; Jolliet-Riant, P; Milliez, J; Jannet, D; Barre, J; Flouvat, B
An isocratic high-performance liquid chromatography method with amperometric detection for the assay of plasma salbutamol is described. The plasma extract is injected into the chromatographic system via a loop column. This insures the purification of the injected extracts and allows a simple and rapid liquid-solid extraction procedure. The good reliability, as shown by the low limit of detection (0.5 ng/ml) and a precision ranging between 5 and 10%, has permitted the investigation of a new mode of administration of salbutamol using a portable subcutaneous infusion pump. Our results show that subcutaneous administration yields plasma levels comparable with those obtained after usual intravenous doses. PMID:1412610
NSDL National Science Digital Library
This Website, from McMaster University, uses the combined skills of artists, writers, programmers, and Web designers to create a resource for the study of Trajan's column, a Roman architectural monument. This 100-foot marble column, built during the reign of Emperor Trajan, 98-117 AD, is topped with a gilded statue of Trajan and decorated with carvings recounting Trajan's rule, primarily the Dacian Wars and his building projects. The heart of the Website is the database of 500 slides of the carvings; indexes allow users to view the slides in thematic groupings such as images of sides of the column, groups organized by subject keywords, or carvings made with specific tools. Cartoons or drawings of the column help to contextualize the details found in the slides, and essays provide more information on its design, construction, and preservation.
Application of a semi-automated 96-well format solid-phase extraction, column-switching, fluorescence detection protocol for the determination of alendronate in human urine samples obtained from a bioequivalence study.
Apostolou, Constantinos; Dotsikas, Yannis; Kousoulos, Constantinos; Tsatsou, Georgia; Colocouri, Filomila; Soumelas, Georgios-Stefanos; Loukas, Yannis L
In the current study, a semi-automated, 96-well format, solid-phase extraction (SPE), analytical column-switching method for alendronate determination in human urine is developed, validated and applied to a bioequivalence study. The current protocol was a substantial improvement of an existing classical method. A robotic liquid handling system was employed to simplify and reduce the time of sample preparation procedure. Automated SPE was carried out using a 96-well cartridge plate and a vacuum control system. Urine samples were determined by applying a column-switching protocol with fluorescence detection. Analysis time, due to the column-switching procedure, was about half of the conventional LC approach (11.5 min instead of 21 min). The method application required the determination of alendronate in urine samples obtained from 96 healthy volunteers as part of a bioequivalence study of two 70 mg alendronate sodium tablets. All major pharmacokinetic parameters of the bioequivalence study were estimated and reported. PMID:17045443
In vitro gastric and intestinal digestions of pulsed light-treated shrimp extracts
Technology Transfer Automated Retrieval System (TEKTRAN)
Pulsed ultraviolet light (PUV), a novel technology most commonly used for microbial inactivation, has recently been employed to effectively mitigate food allergens in peanuts, soybean, shrimp, and almond. Putative mechanisms for the efficacy of PUV in reducing allergen reactivity, include photother...
Testing a prototype pulse generator for a continuous flow system and its use for E. coli inactivation and microalgae lipid extraction.
Flisar, Karel; Meglic, Sasa Haberl; Morelj, Jernej; Golob, Janvit; Miklavcic, Damijan
Among other applications, electroporation is used for the inactivation of pathogens and extraction of substances from microorganisms in liquids where large scale flow systems are used. The aim of our work was therefore to test a pulse generator that enables continuous pulsed electric field (PEF) treatment for Escherichia coli inactivation and microalgae lipid extraction. In the continuous flow PEF system, the flow rate was adjusted so that each bacterial cell received a defined number of pulses. The results of PEF flow treatment showed that the number of pulses influences E. coli inactivation to the same extent as in the previously described cuvette system, i.e., batch system. The continuous flow PEF system was also tested and evaluated for lipid extraction from microalgae Chlorella vulgaris. In control experiments, lipids were extracted via concentration of biomass, drying and cell rupture using pressure or an organic solvent. In contrast, electroporation bypasses all stages, since cells were directly ruptured in the broth and the oil that floated on the broth was skimmed off. The initial experiments showed a 50% oil yield using the electroporation flow system in comparison to extraction with organic solvent. PMID:24713586
NSDL National Science Digital Library
Julie Yu
In this activity, learners separate the components of Gatorade using a home-made affinity column. In doing so, learners model the basic principle of affinity chromatography, a technique used to purify chemicals as well as bio-pharmaceuticals and petroleum products. This resource contains information about affinity chromatography and polarity.
Solid phase extraction method for the determination of iron, lead and chromium by atomic absorption spectrometry using Amberite XAD-2000 column in various water samples
Latif Elci; Aslihan A. Kartal; Mustafa Soylak
This work describes a procedure for the separation¢preconcentration of Fe(III), Pb(II) and Cr(III) from some water samples using a column-filled Amberlite XAD-2000 resin. The analyte ions retained on the column were eluted with 0.5molL?1 HNO3. The analytes in the effluent were determined by atomic absorption spectrometry. Several parameters governing the efficiency of the method were evaluated including pH, resin amount,
Pulsed electromembrane extraction for analysis of derivatized amino acids: A powerful technique for determination of animal source of gelatin samples.
Rezazadeh, Maryam; Yamini, Yadollah; Seidi, Shahram; Aghaei, Ali
Differentiation of animal sources of gelatin is required for many reasons such as some anxieties about bovine spongiform encephalopathy or a ban on consuming porcine gelatin in some religions. In the present work, an efficient method is introduced for determination of animal origin of gelatin samples. The basis of this procedure is the application of pulsed electric field for extraction, preconcentration, and analysis of derivatized amino acids in gelatin. To this end, after derivatization of amino acids of interest by means of o-phthalaldehyde (OPA) for enhancing their ultraviolet (UV) absorbance as well as increasing their lipophilicities, a 137V electric field was applied for 20min with 10min(-1) frequency to make the analytes migrate through a 200Ąm organic liquid membrane into an aqueous acceptor phase. Finally, the acceptor phase was analyzed by HPLC-UV. The proposed technique offered a high efficiency for analysis of amino acids, regarding 43% and 79% as extraction recoveries and 25ng mL(-1) and 50ng mL(-1) as limits of detection (LODs) for asparagine and glutamine, respectively. Therefore, due to sample cleanup ability of the proposed method and obtained preconcentration factors (29 and 53 for asparagine and glutamine, respectively), it could be carried out for differentiation of animal origins of gelatin samples, even if only small amounts of samples are available or in complicated media of foodstuffs and medicament. PMID:25703002
Two-dimensional evaluation of an ion plasma produced by pulsed lasers extracted by non-parallel collectors
NASA Astrophysics Data System (ADS)
Mahdieh, M. H.; Gavili, A.
Two-dimensional hydrodynamics of ion extraction from quasi-neutral plasmas has been calculated numerically for non-parallel ion extractors, and the results compared with those for the parallel case. The ions were assumed to be initially uniform with a very steep density profile at the boundaries, and held between two non-parallel metal plates as cathode and anode with fixed potentials. Experimentally, tunable pulsed lasers through stepwise photo-excitation and photo-ionization or multi-photo-ionization processes can produce such plasma. Poisson's equation was solved simultaneously with the equations of mass and momentum, assuming the Maxwell-Boltzmann distribution for electrons. Ordinary Cartesian co-ordinates are not suitable for the rotated extractor geometry; therefore using the `algebraic method' a transformation from the physical domain into the computational rectangular plane is applied for analysing the irregular boundaries. Such a technique provides adequate resolution for the boundary layer. Using a first-order explicit upwind differencing in an appropriate transformed Cartesian co-ordinate system, the hydrodynamics of the plasma ions between the two non-parallel electrodes was evaluated. In these calculations electric potential, ion density between the two electrodes, and the extraction time were assessed, considering three separate regions for the plasma, i.e. the ion sheath where (ni?neapprox0), the transition region (pre-sheath) (ni = ne), and the quasi-neutral plasma (ni-ne?ni). The results were compared with those for parallel electrodes. A significant discrepancy was found between the two results. From the calculation, the non-uniform asymmetric potential contour, and the ion density contour across the plasma, were obtained for the non-parallel electrodes. For comparison with the parallel extractors, we have also obtained almost the same extraction time for the non-parallel extractors.
Development of an immunoaffinity column method using broad-specificity monoclonal antibodies for simultaneous extraction and cleanup of quinolone and sulfonamide antibiotics in animal muscle tissues
Technology Transfer Automated Retrieval System (TEKTRAN)
This paper describes a novel mixed-bed immunoaffinity column (IAC) method. The IAC was produced by coupling anti-fluoroquinolone and anti-sulfonamide broad-specificity monoclonal antibodies (Mabs) to Sepharose 4B for simultaneously isolating 13 fluoroquinolones (FQs) and 6 sulfonamides (SAs) from s...
Assay of the enantiomers of ibutilide and artilide using solid-phase extraction, derivatization, and achiral-chiral column-switching high-performance liquid chromatography
Chang-yuan L. Hsu; Rodney R. Walters
Ibutilide fumarate and artilide fumarate, new drugs for the treatment of cardiac arrhythmias, each contain a stereogenic center bearing a secondary alcohol group. Reversed-phase achiral-chiral column-switching HPLC separations of the enantiomers of each compound were developed and validated for quantitation in plasma and other biofluids. The key component of the method was derivatization with 1-naphthyl isocyanate, which enhanced the sensitivity
Continuous biosorption of Pb/Cu and Pb/Cd in fixed-bed column using algae Gelidium and granulated agar extraction algal waste.
Vilar, VĒtor J P; Loureiro, Josķ M; Botelho, Cidßlia M S; Boaventura, Rui A R
Continuous metal ions biosorption from Pb/Cu and Pb/Cd solutions onto seaweed Gelidium sesquipedale and a composite material prepared from an industrial algal waste was performed in a packed bed column. A binary Langmuir equation describes well the equilibrium data and indicates a good adsorption capacity. In the sorption process, Cd and Cu break through the column faster than Pb due to its lower affinity for the biosorbent. An overshoot in the outlet Cd concentration was observed and explained by competitive adsorption between Pb and Cd, whereby the higher Pb affinity for the biosorbent displaces bound Cd ions. A small overshoot happens for Cu adsorption in the presence of Pb ions. Desorption using 0.1 M HNO3 as eluant, was 100% effective. A mass transfer model for the adsorption and desorption processes, considering an external and intraparticle film resistance, adequately simulates the column performance. A binary Langmuir equation was used to describe equilibrium for the saturation process and a mass action law for the desorption process. Elution process is defined as an ion exchange mechanism, between protons and metal ions. PMID:18162305
Complexation Study of Humic Acids Extracted from Forest and Sahara Soils with Zinc (II) and Cadmium (II) by Differential Pulse Anodic Stripping Voltammetry (DPASV) and Conductimetric Methods
Achour Terbouche; Safia Djebbar; Ouassini Benali-Baitich; Didier Hauchard
The complexation of heavy metals, present in their dissolved state at relevant trace levels, with new humic acids (HAs) isolated\\u000a from Yakouren forest (YHA) and Sahara (Tamenrasset: THA) soils has been studied by differential pulse anodic stripping voltammetry\\u000a (DPASV) at a hanging mercury drop electrode and conductimetry methods. After extraction and purification, humic acids were\\u000a characterized by elemental analyses, atomic
Mass transfer in aqueous two-phases system packed column
L Igarashi; T. G Kieckbusch; T. T Franco
The behavior of xylanase extraction in a packed column using polyethylene glycol (PEG) 4000 and dipotassium phosphate was studied. The possibility of using the packed column in continuous operations for enzyme extraction was studied since the previous work had only addressed the semi-continuous extraction of enzyme. The influence of several kinds of packings, Raschig rings, glass spheres and polystyrene rings
Solid phase micro extraction coupled with on-column GC\\/ECD for the post-blast analysis of organic explosives
Stķphane Calderara; Dominique Gardebas; Fabienne Martinez
Gas chromatographic analysis with electron capture detection is very sensitive to post-blast residues and useful for the determination of organic explosive molecules. But many compounds extracted from the matrices may interfer with the explosives.Using SPME, most interfering compounds are eliminated so the identification is easier. Another advantage of the technique is a low limit of detection. In this study, four
Determination of sulfonamides in bovine milk with column-switching high performance liquid chromatography using surface imprinted silica with hydrophilic external layer as restricted access and selective extraction material.
Xu, Wenjuan; Su, Shufang; Jiang, Ping; Wang, Huaisong; Dong, Xiangchao; Zhang, Min
A novel restricted access-molecularly imprinted material (RA-MIP) with selectivity for sulfonamides was synthesized using initiator-transfer agent-terminator (iniferter) method, a "living"/controlled radical polymerization technique. The material was prepared by grafting two layers with different functions on the silica support. To perform a "grafting from" polymerization, iniferter was immobilized on the surface of silica. The internal sulfamethazine imprinted polymer and the external poly(glycidyl methacrylate) [poly(GMA)] were then grafted successively. The hydrophilic structures were formed on the external layer of the material by the hydrolysis of the linear poly(GMA) for protein removal. The result has shown that this restricted access-MIP grafted silica (RA-MIP-SG) not only has the selectivity for the template and its analog, but also has the ability of exclusion for bovine serum albumin (BSA). It indicated that the material possesses both properties of molecularly imprinted polymer (MIP) and restricted access material (RAM). Using RA-MIP-SG as pre-column, a column-switching HPLC method was established for the determination of sulfonamides in bovine milk. Direct sample injection was performed in the analysis, which provides a convenient analytical procedure. Good linearity in the range of 2-400 ng mL(-1) (R>0.998) has been obtained for seven sulfonamides in the study. The recoveries of all the analytes at three concentration levels are between 93% and 107% with the RSD<8.0%. The limits of quantification and limits of detection are less than or equal to 2.7 ng mL(-1) and 0.8 ng mL(-1) respectively. It demonstrated this RA-MIP-SG can be applied in sample extraction and clean-up for the determination of sulfonamides in bovine milk by direct injection and column-switching HPLC with good efficiency and reliability. PMID:20934183
KrF laser fusion: perform optical systems study of direct short pulse extraction. Final technical report, 26 June 1978-14 March 1981
Bradford, Jr, R S; Betts, J A; Aprahamian, R; Livingston, P M
KrF is a prime candidate for a laser inertial confinement fusion (ICF) driver, however, there are still scaling issues to be addressed. The purpose of this program is to determine KrF performance in a regime of ICF interest both experimentally and analytically. Using a master oscillator-power amplifier (MOPA) configuration, 100J has been obtained from a five liter optical volume KrF amplifier pumped at 300 KW/cm/sup 3/ peak at the end of a 500 nsec pulse. A normalized input flux of 0.4 was required to reduce amplified spontaneous emission (ASE) to one half the free running value. A peak extraction efficiency of 0.46 was obtained under these conditions at 1 atm total pressure. The TRW kinetics model has been refined to give excellent agreement with high and low pump regimes. An integrated kinetics and pulse propagation code has also been developed and agrees well with experiment.
Determination of cadmium by differentialn pulse anodic-stripping voltammetry after salting-out extraction into acetonitrile.
Nagaosa, Y; Yamada, T
A selective and specific method is presented for anodic-stripping voltammetric determination of cadmium after extraction with 0.1Mtetrabutylammonium iodide solution in acetonitrile from aqueous ammonium sulphate solutions. The detection limit of this method is 0.2 ng ml (in the acetonitrile extract). Interference from matrices or large amounts of elements reduced at more positive potentials can be eliminated by prior extraction. The method has been applied to trace analysis for cadmium in zinc, lead and indium metals, and some inorganic salts. PMID:18963613
Liquid chromatographic extraction medium
Horwitz, E. Philip (Naperville, IL); Dietz, Mark L. (Evanston, IL)
A method and apparatus for extracting strontium and technetium values from biological, industrial and environmental sample solutions using a chromatographic column is described. An extractant medium for the column is prepared by generating a solution of a diluent containing a Crown ether and dispersing the solution on a resin substrate material. The sample solution is highly acidic and is introduced directed to the chromatographic column and strontium or technetium is eluted using deionized water.
Rockland, Kathleen
ōColumn,ö like ōgene,ö has both conceptual and linguistic shortcomings. The simple question ōwhat is a columnö is not easy to answer and the word itself is not easy to replace. In the present article, I have selected five ...
Methods of analysis by the U.S. Geological Survey National Water Quality Laboratory : determination of organophosphate pesticides in whole water by continuous liquid-liquid extraction and capillary-column gas chromatography with flame photometric detection
Jha, Virendra K.; Wydoski, Duane S.
A method for the isolation of 20 parent organophosphate pesticides and 5 organophosphate pesticide degradates from natural-water samples is described. Compounds are extracted from water samples with methylene chloride using a continuous liquid-liquid extractor for 6 hours. The solvent is evaporated using heat and a flow of nitrogen to a volume of 1 milliliter and solvent exchanged to ethyl acetate. Extracted compounds are determined by capillary-column gas chromatography with flame photometric detection. Single-operator derived method detection limits in three water-matrix samples ranged from 0.003 to 0.009 microgram per liter. Method performance was validated by spiking all compounds in three different matrices at three different concentrations. Eight replicates were analyzed at each concentration in each matrix. Mean recoveries of most method compounds spiked in surface-water samples ranged from 54 to 137 percent and those in ground-water samples ranged from 40 to 109 percent for all pesticides. Recoveries in reagent-water samples ranged from 42 to 104 percent for all pesticides. The only exception was O-ethyl-O-methyl-S-propylphosphorothioate, which had variable recovery in all three matrices ranging from 27 to 79 percent. As a result, the detected concentration of O-ethyl-O-methyl-S-propylphosphorothioate in samples is reported in this method with an estimated remark code. Based on the performance issue, two more compounds, disulfoton and ethion monoxon, also will be reported in this method with an estimated remark code. Estimated-value compounds, which are ?E-coded? in the data base, do not meet the performance criteria for unqualified quantification, but are retained in the method because the compounds are important owing to high use or potential environmental effects and because analytical performance has been consistent and reproducible.
Mix-mode TiO-C18 monolith spin column extraction and GC-MS for the simultaneous assay of organophosphorus compounds and glufosinate, and glyphosate in human serum and urine.
Saito, Takeshi; Aoki, Hiromichi; Namera, Akira; Oikawa, Hiroshi; Miyazaki, Shota; Nakamoto, Akihiro; Inokuchi, Sadaki
A rapid, specific, and sensitive method for the simultaneous quantitation of organophosphates (fenitrothion (MEP), malathion, and phenthoate (PAP)), glufosinate (GLUF), and glyphosate (GLYP) in human serum and urine by gas chromatography-mass spectrometry (GC-MS) has been validated. All of the targeted compounds together with the internal standard were extracted from the serum and urine using a mix-mode TiO-C(18) monolithic spin column. The recovery of organophosphates from serum and urine ranged from 12.7 to 49.5%. The recovery of GLUF and GLYP from serum and urine ranged from 1.9 to 7.9%. The intra- and inter-accuracy and precision (expressed as relative standard deviation, %RSD) were within 96.7-107.7% and 4.0-13.8%, respectively. The detection and quantitation limits for serum and urine were 0.1 and 0.1 Ąg/ml, respectively, for organophosphates, 0.1 and 0.5 Ąg/ml, respectively for GLUF and GLYP. The method had linear calibration curves ranging from 0.1 to 25.0 Ąg/ml for organophosphates and 0.5-100.0 Ąg/ml for GLUF, and GLYP. The validated method was successfully applied to a clinical GLYP poisoning case. PMID:21985924
Determination of serotonin, noradrenaline, dopamine and their metabolites in rat brain extracts and microdialysis samples by column liquid chromatography with fluorescence detection following derivatization with benzylamine and 1,2-diphenylethylenediamine.
Yoshitake, Takashi; Kehr, Jan; Yoshitake, Shimako; Fujino, Kaoru; Nohta, Hitoshi; Yamaguchi, Masatoshi
A highly selective and sensitive column liquid chromatographic method for fluorescence determination of serotonin (5-HT), dopamine (DA), noradrenaline (NA) and their related metabolites 5-hydroxyindole-3-acetic acid (5-HIAA) and 3,4-dihydroxyphenylacetic acid (DOPAC) following derivatization with benzylamine and 1,2-diphenylethylenediamine (DPE) is described. The monoamines and the metabolites (20 microl samples) were derivatized in a two-step reaction, initiated with 20 microl of 0.3M benzylamine in 0.3M 3-cyclohexylaminopropanesulfonic acid (CAPS) buffer (pH 10.0), (for 5-HT, 5-HIAA, 2 min, 24 degrees C) and followed by 20 microl of 0.1M DPE in 0.3M glycine buffer (pH 10.0), (for DA, NA, DOPAC, 20 min, 50 degrees C). Both reagents contained 0.02 M potassium hexacyanoferrate(III) and 50% (v/v) methanol. The resulting highly fluorescent and stable benzoxazole derivatives were isocratically separated on a reversed-phase column (150 mm x 1.5 mm i.d., packed with C18 silica, 5 microm) within 45 min. Using fluorescence detection at ex. and em. wavelengths of 345 and 480 nm, respectively, the detection limit (signal-to-noise ratio of 3) for 5-HT, DA, NA, 5-HIAA, L-DOPA and DOPAC ranged between 0.08 and 5.65 fmol per 20-microl injection (12-847.5 pM in standard solution). The concentrations of monoamines (expressed in microg/g wet weight, mean +/- S.E.M., n=5) in tissue extracts from the rat striatum were: 0.45+/-0.05 (5-HT), 4.27+/-0.08 (DA), 0.27+/-0.04 (NA), 0.55+/-0.06 (5-HIAA), 1.26+/-0.16 (L-DOPA) and 1.62+/-0.11 (DOPAC). Microdialysis samples were collected in 20 min intervals from the probes implanted in the striatum of awake rats. The basal monoamine levels (in fmol/20 microl, mean +/- S.E.M., n=5) in the dialysates were: 4.0+/-0.7 (5-HT), 78.4+/-9.1 (DA), 6.4+/-0.8 (NA), 785.5+/-64.5 (5-HIAA) and 5504.5+/-136.5 (DOPAC). It is concluded that the new fluorescence derivatization protocol provides an excellent means for simultaneous determination of all three monoamines both in the complex samples (e.g. brain homogenates) and also at trace levels, such as those found in the microdialysis samples. PMID:15203027
Transient flow and heating characteristics in a pinched plasma column.
NASA Technical Reports Server (NTRS)
York, T. M.; Stover, E. K.
The generation of axial flow and heating of an argon plasma in a pinched plasma column of a pulsed, linear z-pinch device was examined experimentally and analytically. Transient (about 5 microsec) axial pressure profiles identify three characteristic periods in the column history. These include (1) strong axial pressure asymmetry indicative of plasma streaming, (2) isotropic, rapidly rising plasma pressure indicative of plasma heating, and (3) column breakup. An efficient conversion of radial collapse to axial streaming velocity is identified. Mechanisms for such an effect and subsequent heating are evaluated; significance to transients in pulsed plasma accelerators is identified.
Distillation Column Flooding Predictor
George E. Dzyacky
The Flooding PredictorÖ is a patented advanced control technology proven in research at the Separations Research Program, University of Texas at Austin, to increase distillation column throughput by over 6%, while also increasing energy efficiency by 10%. The research was conducted under a U. S. Department of Energy Cooperative Agreement awarded to George Dzyacky of 2ndpoint, LLC. The Flooding PredictorÖ works by detecting the incipient flood point and controlling the column closer to its actual hydraulic limit than historical practices have allowed. Further, the technology uses existing column instrumentation, meaning no additional refining infrastructure is required. Refiners often push distillation columns to maximize throughput, improve separation, or simply to achieve day-to-day optimization. Attempting to achieve such operating objectives is a tricky undertaking that can result in flooding. Operators and advanced control strategies alike rely on the conventional use of delta-pressure instrumentation to approximate the columnÆs approach to flood. But column delta-pressure is more an inference of the columnÆs approach to flood than it is an actual measurement of it. As a consequence, delta pressure limits are established conservatively in order to operate in a regime where the column is never expected to flood. As a result, there is much ōleft on the tableö when operating in such a regime, i.e. the capacity difference between controlling the column to an upper delta-pressure limit and controlling it to the actual hydraulic limit. The Flooding PredictorÖ, an innovative pattern recognition technology, controls columns at their actual hydraulic limit, which research shows leads to a throughput increase of over 6%. Controlling closer to the hydraulic limit also permits operation in a sweet spot of increased energy-efficiency. In this region of increased column loading, the Flooding Predictor is able to exploit the benefits of higher liquid/vapor traffic that produce increased contact area and lead to substantial increases in separation efficiency ¢ which translates to a 10% increase in energy efficiency on a BTU/bbl basis. The Flooding PredictorÖ operates on the principle that between five to sixty minutes in advance of a flooding event, certain column variables experience an oscillation, a pre-flood pattern. The pattern recognition system of the Flooding PredictorÖ utilizes the mathematical first derivative of certain column variables to identify the columnÆs pre-flood pattern(s). This pattern is a very brief, highly repeatable, simultaneous movement among the derivative values of certain column variables. While all column variables experience negligible random noise generated from the natural frequency of the process, subtle pre-flood patterns are revealed among sub-sets of the derivative values of column variables as the column approaches its hydraulic limit. The sub-set of column variables that comprise the pre-flood pattern is identified empirically through in a two-step process. First, 2ndpointÆs proprietary off-line analysis tool is used to mine historical data for pre-flood patterns. Second, the column is flood-tested to fine-tune the pattern recognition for commissioning. Then the Flooding PredictorÖ is implemented as closed-loop advanced control strategy on the plantÆs distributed control system (DCS), thus automating control of the column at its hydraulic limit.
Optimisation and application of accelerated solvent extraction and flash chromatography for quantification of PCBs in tree barks and XAD-2 passive samplers using GC-ECD with dual columns.
Guķguen, Florence; Stille, Peter; Millet, Maurice
An analytical method for the quantification of Polychlorinated biphenyls (PCBs) concentrations in XAD-2 passive air samplers (PAS) and tree barks collected close to the Rhine River between France and Germany was developed. This method used Accelerated Solvent Extraction (ASE) followed by a purification step by flash chromatography using a 4gr cartridge (3 g of silica gel and 1 g of 44% acidified silica) and analysis by GC-ECD with dual columns. Quantification (QL) and detection (DL) limits varied 0.5 from and 5.7 ng PAS(-1) and from 0.5 and 3.0 ng PAS(-1) respectively. For tree barks, quantification and detection limits were calculated for each congener on washed tree bark sample with a signal to noise ratio of 3:1 and 10:1 (corresponding to a LQ in the range of 1-4 ng per bark sample by congeners). Uncertainties on each congener concentration were calculated to be in the range of 3-20% XAD-2 passive samplers were field calibrated by using Hi-vol. Samplers. Sampling rates of 4.2, 11.5, 1.6, and 7.9 m(3) PAS(-1) d(-1) for tri-, tetra-, penta- hexa-PCBs, respectively were obtained and are comparable to those already obtained with PUF-PAS for gas phase only (gas/particle distribution was 90/10). Method was applied to real atmospheric samples collected by XAD-2 passive samplers and tree barks in the east of France. PMID:23622537
Water vapor column abundance retrievals during FIFE
C. J. Bruegge; J. E. Conel; R. O. Green; J. S. Margolis; R. G. Holm; G. Toon
This work is part of the First International Satellite Land Surface Climatology Project (ISLSCP) Field Experiment (FIFE), an international land-surface-atmosphere experiment aimed at improving the way climate models represent energy, water, heat, and carbon exchanges, and improving the utilization of satellite based remote sensing to monitor such parameters. The authors report on the use of a sunphotometer to extract column
A New Pulsed Glow Discharge Source With Enhanced Ion Extraction for Small Non-Conductive Samples or Atmospheric Sampling
Jackson, Glen P. [Ohio University, Athens; Haire, Richard {Dick} G [ORNL; Duckworth, Douglas {Doug} C [ORNL
An ionization source designed to efficiently utilize sub-milligram quantities of electrically non-conducting compounds (i.e. oxides) for prolonged periods of mass spectrometric analysis is described. The source is coupled to a quadrupole ion trap mass spectrometer in this report, but could readily be modified for alternative types of mass spectrometers. The coaxial-design glow discharge ion source is unique in that it incorporates a focusing lens behind the discharge surface to steer ions towards the ion sampling plate and thereby improve sensitivity. Non-conducting oxide samples are infused in indium and set in one end of an electrically conductive rod, to which the voltage is applied. Transmission efficiency is sufficient to allow the measurement of isotopes of tungsten from a tungsten rod using glow discharge pulse widths as narrow as 2 {micro}s, which is on the order of single-atom layer sputtering. The sputtering and ionization processes occurring in the discharge produces mainly atomic metal ions, regardless of the chemical form of the metals in the samples. This latter aspect is particularly useful for intended applications involving actinide samples, and allows a minimal amount of sample handling. In a second application, a metal capillary is used in place of the rod to create an atmospheric sampling glow discharge. In this mode, the ion-focusing lens was also found to enhance ion signals arising from volatile vapors entering the discharge from the capillary.
William I. Gasarch
Welcome to the Book Reviews Column. We hope to bring you at least two reviews of books every month. In this column four books are reviewed. 1. Stable Marriage and its Relation to Other Combinatorial Problems: An Intro- duction to Algorithm Analysis by Donald Knuth. Reviewed by Tim McNichol. This book uses the stable marriage problem as motivation to look
Luttrell, G.H.; Adel, G.T.; Yoon, R.H.
Many investigators believe that column flotation cells offer significant advantages over standard mechanical machines for the flotation of fine particles. However, because of their unique design and operation, conventional techniques for flotation cell scale-up and design cannot be applied to columns. In an attempt to help alleviate this problem, a population balance model based on first principles has been developed for fine particle flotation in a column. Two different terms have been considered in the model, i.e., transport and rate. Transport terms, incorporating fluid flow and buoyancy, are used to describe the movement of air bubbles, unattached particles and bubble-particle aggregates along the length of the column. Rate terms, which describe the bubble-particle attachment process, have been derived from first principle considerations. Because the model is based on first principles, it can be useful for the design, control, optimization and scale-up of column flotation cells. 9 refs., 12 figs.
NASA Astrophysics Data System (ADS)
Holmes, Jon L.
The Features area of JCE Online is now readily accessible through a single click from our home page. In the Features area each column is linked to its own home page. These column home pages also have links to them from the online Journal Table of Contents pages or from any article published as part of that feature column. Using these links you can easily find abstracts of additional articles that are related by topic. Of course, JCE Online+ subscribers are then just one click away from the entire article. Finding related articles is easy because each feature column "site" contains links to the online abstracts of all the articles that have appeared in the column. In addition, you can find the mission statement for the column and the email link to the column editor that I mentioned above. At the discretion of its editor, a feature column site may contain additional resources. As an example, the Chemical Information Instructor column edited by Arleen Somerville will have a periodically updated bibliography of resources for teaching and using chemical information. Due to the increase in the number of these resources available on the WWW, it only makes sense to publish this information online so that you can get to these resources with a simple click of the mouse. We expect that there will soon be additional information and resources at several other feature column sites. Following in the footsteps of the Chemical Information Instructor, up-to-date bibliographies and links to related online resources can be made available. We hope to extend the online component of our feature columns with moderated online discussion forums. If you have a suggestion for an online resource you would like to see included, let the feature editor or JCE Online (email@example.com) know about it. JCE Internet Features JCE Internet also has several feature columns: Chemical Education Resource Shelf, Conceptual Questions and Challenge Problems, Equipment Buyers Guide, Hal's Picks, Mathcad in the Chemistry Curriculum, and WWW Site Review. These columns differ from the print feature columns in that they use the Internet as the publication medium. Doing so allows these features to include continually updated information, digital components, and links to other online resources. The Conceptual Questions and Challenge Problems feature of JCE Internet serves as a good example for the kinds of resources that you can expect to find in an online feature column. Like other columns it contains a mission statement that defines the role of the column. It includes a digital library of continually updated examples of conceptual questions and challenge problems. (As I write this we have just added several new questions to the library.) It also includes a list of links to related online resources, information for authors about how to write questions and problems, and information for teachers about how to use conceptual questions and challenge problems. Teaching with Technology home page at JCE Online. One-Stop Feature Shop The updated Feature area of JCE Online offers information about all JCE feature columns in one place. It gives you a quick and convenient way to access a group of articles in a particular subject area. It provides authors and readers with a good definition of the column and its mission. It complements the print feature columns with online resources. It provides up-to-date bibliographies for selected areas of interest. And last, but not least, it provides that email address you can use to send that message of appreciation to the feature editor for his or her contribution to JCE and the chemical education community.
Separation of intracellular proteins from Candida utilis using reverse micelles in a spray column
Dong Hoon Han; Sang Yup Lee; Won Hi Hong
Recovery of intracellular proteins from Candida utilis by reverse micellar extraction in a simple spray column was studied. The effects of varying the number of circulations, the flow rate, and the column length on the amount of extracted proteins were examined. The optimal number of circulations and the flow rate for the extraction of proteins were 2 and 0.2 ml\\/sec,
Mass transfer in aqueous two-phases system packed column.
Igarashi, L; Kieckbusch, T G; Franco, T T
The behavior of xylanase extraction in a packed column using polyethylene glycol (PEG) 4000 and dipotassium phosphate was studied. The possibility of using the packed column in continuous operations for enzyme extraction was studied since the previous work had only addressed the semi-continuous extraction of enzyme. The influence of several kinds of packings, Raschig rings, glass spheres and polystyrene rings were studied as well the superficial velocity ratio of the salt and the PEG phases. Packed column showed a good efficiency of overall mass transfer coefficient, around three times higher than sieve plate column, for xylanase extraction. The best selectivity was obtained with the polystyrene ring where 94% of xylanase was recovery to the polymeric whereas just 3% of contaminant was recovery to this phase. The residence time distribution was adjusted by the Model of Reactors in Series. PMID:15177163
Nuclear reactor control column
Bachovchin, Dennis M. (Plum Borough, PA)
The nuclear reactor control column comprises a column disposed within the nuclear reactor core having a variable cross-section hollow channel and containing balls whose vertical location is determined by the flow of the reactor coolant through the column. The control column is divided into three basic sections wherein each of the sections has a different cross-sectional area. The uppermost section of the control column has the greatest cross-sectional area, the intermediate section of the control column has the smallest cross-sectional area, and the lowermost section of the control column has the intermediate cross-sectional area. In this manner, the area of the uppermost section can be established such that when the reactor coolant is flowing under normal conditions therethrough, the absorber balls will be lifted and suspended in a fluidized bed manner in the upper section. However, when the reactor coolant flow falls below a predetermined value, the absorber balls will fall through the intermediate section and into the lowermost section, thereby reducing the reactivity of the reactor core and shutting down the reactor.
NSDL National Science Digital Library
Johnson, Craig
This module, created by Craig Johnson of Central Washington University, "incorporates engineering design (using smart spreadsheets) into a laboratory activity focusing on columns made of composite materials." In this lab, students will simulate the use of composite columns and use spreadsheets to optimize design for engineering performance. The module features an abstract, objective, curriculum overview, procedures, mathematical calculations and references. The objectives of the module are to design appropriate composite column structures, fabricate composite using appropriate methods and critically evaluate composite's performance referencing predications. This is a great resource to either enhance or create new curriculum for instructors.
Sequencing of modified oligonucleotides using in-source fragmentation and delayed pulsed ion extraction matrix-assisted laser desorption ionization time-of-flight mass spectrometry
NASA Astrophysics Data System (ADS)
Wang, Bing H.; Hopkins, Christopher E.; Belenky, Alexei B.; Cohen, Aharon S.
Matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOFMS) was used to sequence modified oligonucelotides (MONs). Under delayed pulsed ion extraction conditions, sequence ions of MONs resulting from fragmentation within the ion source can be observed. In this work, several common types of antisense MONs with sizes up to 25-mer were studied including an oligodeoxynucleotide (ODN) of phosphorothioate-phosphodiester (PS-PO) chimera, an all PS ODN, a partially 2'-O-methylated all PS oligodeoxyribonucleotide-oligoribonucleotide (ODN-ON) chimera, and an ODN of phosphorothioate-methylphosphonate (PS-MP) chimera. The sequence ions observed include `w', `d', as well as hitherto little discussed `a' and `z' ions. While a complete sequence can be constructed from `w' ions for chimeric PS-PO ODN, all PS ODN, and chimeric PS ODN-ON, `a' ions or `d' ions provide useful supplemental information. For the PS-MP ODN, however, `d' ions are critical in filling the gap in the sequence constructed from `w' ions. The method provides a rapid quality control tool in oligonucleotide synthesis allowing sequence verification to be accomplished in minutes rather than hours needed by chemical or enzymatic methods. The observation that the fragmentation pattern in the PS ON region is rather similar to that of PS ODN together with the observation of `a' ions suggests that backbone cleavage pathways may not always involve nucleobases losses. Fragmentation mechanisms alternative to those found in MALDI-TOFMS literature have been proposed.
K. C. Overman; D. F. Mix; J. A. Lookadoo
A modification of conventional Fourier transforms is presented. This modification is called the pulse sorting transform (PST) and is useful in extracting information from signals comprised of interleaved pulse trains. A brief derivation of the PST from the conventional transform is presented, followed by theorems that describe the PST's properties. Several examples of how the PST can be an effective
Towards Atomic Column-by-Column Spectroscopy
Pennycook, S.J.; Rafferty, B.
The optical arrangement of the scanning transmission electron microscope (STEM) is ideally suited for performing analysis of individual atomic columns in materials. Using the incoherent Z-contrast image as a reference, and arranging incoherent conditions also for the spectroscopy, a precise correspondence is ensured between features in the inelastic image and elastic signals. In this way the exact probe position needed to maximise the inelastic signal from a selected column can be located and monitored during the analysis using the much higher intensity elastic signal. Although object functions for EELS are typically less than 1 {Angstrom} full width at half maximum, this is still an order of magnitude larger than the corresponding object functions for elastic (or diffuse) scattering used to form the Z-contrast image. Therefore the analysis is performed with an effective probe that is significantly broader than that used for the reference Z-contrast image. For a 2.2 {Angstrom} probe the effective probe is of the order of 2.5 {Angstrom}, while for a 1.3 {Angstrom} probe the effective probe is 1.6 {Angstrom}. Such increases in effective probe size can significantly reduce or even eliminate contrast between atomic columns that are visible in the image. However, this is only true if we consider circular collector apertures. Calculations based upon the theory of Maslen and Rossouw (Maslen and Rossouw 1984; Rossouw and Maslen 1984) show that employing an annular aperture can reduce the FWHM of the inelastic object function down to values close 0.1 {Angstrom}. With practical aperture sizes it should be possible to achieve this increased spatial resolution without loosing too much signal.
Improved protocols for quantitative determination of metabolites from biological samples using high performance ionic-exchange chromatography with conductimetric and pulsed amperometric detection.
Groussac; Ortiz; Franńois
Simple and reliable protocols are described for an extensive analysis of metabolites in extracts from different biological sources. The separation was performed by high performance ionic-exchange chromatography (HPIC) at alkaline pH using two types of chromatography columns and two detection methods. Organic acids and inorganic anions were separated on an ionPac AS11 column using a 0.5 to 35 mM Na0H gradient. Detection limits in the range of milligrams per liter were achieved by use of a conductivity detector equipped with an anion self-regenerating suppressor. Twelve phosphorylated compounds belonging to the glycolytic and the pentose phosphate pathways could be resolved on a CarboPac PA1 column using a Na0H/Na-acetate gradient. Quantification was achieved by pulsed amperometry with detection limits in the micromolar range. Cell extracts obtained by extraction in boiling buffered ethanol described previously could be directly injected onto HPIC columns for the separation of metabolites because the extraction procedure affected neither the retention time nor the stability of most of the metabolites, and yielded very clean chromatograms. These improved protocols were applied for a dynamic analysis of intracellular metabolites in Saccharomyces cerevisiae in response to a glucose pulse. PMID:10862877
Taniguchi, Takumi
Sepsis induces the activation of complement and the release of inflammatory cytokines such as TNF-alpha and IL-1beta. The inflammatory cytokines and nitric oxide induced by sepsis can decrease systemic vascular resistance, resulting in profound hypotension. The combination of hypotension and microvascular occlusion results in tissue ischemia and ultimately leads to multiple organ failure. Recently, several experimental and clinical studies have reported that treatment for adsorption of cytokines is beneficial during endotoxemia and sepsis. Therefore, the present article discusses cytokine adsorbing columns. These columns, such as CytoSorb, CYT-860-DHP, Lixelle, CTR-001 and MPCF-X, the structures of which vary significantly, have excellent adsorption rates for inflammatory cytokines such as TNF-alpha, IL-1beta, IL-6 and IL8. Many studies have demonstrated that treatment with cytokine adsorbing columns has beneficial effects on the survival rate and inflammatory responses in animal septic models. Moreover, several cases have been reported in which treatment with cytokine adsorbing columns is very effective in hemodynamics and organ failures in critically ill patients. Although further investigations and clinical trials are needed, in the future treatment with cytokine adsorbing columns may play a major role in the treatment of hypercytokinemia such as multiple organ failure and acute respiratory distress syndrome. PMID:20473001
Extracting Information on Rain-Induced Pulses of Ecosystem Respiration across Scales Spanning the Plot, Canopy and Planetary Boundary Layer (Invited)
NASA Astrophysics Data System (ADS)
Baldocchi, D. D.; Ma, S.; Hatala, J.; Giolio, B.
Semi-arid ecosystems experience huge pulses in respiration, following rain events. Here we characterize the dynamics of these rain-induced pulses by examining field-scale flux measurements from an annual grassland and oak savanna understory that consisted of 50 pulse events collected from over 18 site-years of measurements. We examine this problem in terms of antecedent conditions (e.g. number of prior pulses, exposure to sunlight) and current conditions (amount of rain, amount of dead vegetation). Causative explanations are provided by a set of laboratory and field manipulation studies on litter samples that were exposed to different levels of rain and sunlight--our working hypothesis is that the magnitude of the respiration pulse is modulated by differing degrees of photodegradation. To understand the regional extent of the pulses, we interpret time courses in CO2 concentration with a planetary boundary layer box model. The magnitude of the rain-induced respiration pulses is a function of the exposure of litter to sunlight, so greater pulses emanate from an open grassland than the understory of a savanna. These pulses can result in CO2 effluxes that approach 8 gC m-2 d-1, and these effluxes remain elevated, above background, for up to 20 days. We find that the pulses are regional in nature because they can cause a sudden jump in CO2 in the well-mixed planetary boundary layer of over 30 ppm.
Heat Exchanger Technologies for Distillation ColumnsĀ
Polley, G. T.
component rather than the mixture bubble point (assumed with the 'integral' assumption) (Figure 2). ITvapoUT I [./"-------' Where separation occurs, part of the bundle is 'submerged' in condensate. This 'subennergence' can give rise to significant... should be given a downward incline of 3-SO. Intermediate Condensers The extraction of heat from an intermediate point in a distillation column as heat source for a heat pump or for use in an integration scheme can result in significant energy...
ERIC Educational Resources Information Center
Leenhouts, Robin
This article describes a clay project for students studying Greece and Rome. It provides a wonderful way to learn slab construction techniques by making small clay column capitols. With this lesson, students learn architectural vocabulary and history, understand the importance of classical architectural forms and their influence on today'sģ
D. F. MacMillan; B. A. Smith; R. P. Dubrule
A description is given of a barrier member fixed in the end of a fuel column retaining spring to prevent contact between the retaining spring and the adjacent end plug of the fuel element whereby contamination of the weld between the cladding tube and end plug with retaining spring material is avoided. 12 claims, 5 drawing figures.
Automated solid-phase extraction and coupled-column reversed-phase liquid chromatography for the trace-level determination of low-molecular-mass carbonyl compounds in air
P. R. Kootstra; H. A. Herbold
This study reports the development of a coupled-column RPLC method for the trace level determination of several volatile aldehydes in ambient air. Carbonyls in air are sampled using a ozone scrubber and SPE C18 cartridges which are pretreated with 2,4-dinitrophenylhydrazone. The method is used for the separation of 13 different aldehydes and ketones. All analytes are separated without high blanks
Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey
11. TIMBER COLUMN AND CAST IRON COLUMN CAP IN FIFTH FLOOR WAREHOUSE SPACE. VIEW TO SOUTHWEST. - Commercial & Industrial Buildings, Becker-Hazelton Company Warehouse, 280 Iowa Street, Dubuque, Dubuque County, IA
The Frequency Shifting of Femtosecond Laser Pulses
Glenn Bryant Focht
Two new and widely applicable methods of shifting the frequency of femtosecond laser pulses have been developed experimentally and theoretically analyzed: (1) intracavity frequency doubling, for low energy (nanojoule) pulses, and (2) blue shifting in a laser-produced plasma, for high energy (millijoule) pulses. For the first method, we efficiently extract an ultraviolet femtosecond pulse train of milliwatt average power and
Transient flow and heating in a pinched plasma column
NASA Technical Reports Server (NTRS)
York, T. M.; Stover, E. K.
The axial flow and heating of an argon plasma in a pinched plasma column of a pulsed, linear z-pinch device was experimentally examined with a unique pressure sensing instrument capable of resolving mass flow properties. Transient axial pressure profiles identify periods of intense flow and heating. Mechanisms generating such effects are considered.
Column test-rig facility for column scanning studies
NASA Astrophysics Data System (ADS)
Zain, Rasif M.; Roslan, Y.
Distillation columns are considered as one of the most critical components in oil and gas plants. The plant performance depends on the ability of these columns to function as intended. Defective columns may lead to serious consequences to the plant operation, and hence the quality of product. In order to perform any inspection techniques to distillation column for NDT practitioner, the best facility was designed when the adjustable defeats of distillation column test rig has been developed. The paper discussed the development and the function of this facility.
Column test-rig facility for column scanning studies
NASA Astrophysics Data System (ADS)
Zain, Rasif M.; Roslan, Y.
Distillation columns are considered as one of the most critical components in oil and gas plants. The plant performance depends on the ability of these columns to function as intended. Defective columns may lead to serious consequences to the plant operation, and hence the quality of product. In order to perform any inspection techniques to distillation column for NDT practitioner, the best facility was designed when the adjustable defeats of distillation column test rig has been developed. The paper discussed the development and the function of this facility.
Flach, G.
PORFLOW related analyses supporting a Sensitivity Analysis for Saltstone Disposal Unit (SDU) column degradation were performed. Previous analyses, Flach and Taylor 2014, used a model in which the SDU columns degraded in a piecewise manner from the top and bottom simultaneously. The current analyses employs a model in which all pieces of the column degrade at the same time. Information was extracted from the analyses which may be useful in determining the distribution of Tc-99 in the various SDUs throughout time and in determining flow balances for the SDUs.
Experiments on radiation-driven waves produced during the production of a radially confined plasma column
D. Dufresne; P. A. Pincosy; J.-P. Caressa; P. Bournot; M. Autric
A plasma column radially confined by a magnetic field was produced in hydrogen by the light energy of a CO2 laser (200 J and a pulse length of 2 microsec). The absorption zone which normally propagates toward the laser from the focal spot was eliminated to permit the study, in an approximately constant column diameter, of front propagation regimes as
Application of a new hybrid organic¢inorganic monolithic column for efficient deoxyribonucleic acid purification
Shengbing Yu; Jing Geng; Ping Zhou; Jing Wang; Airong Feng; Xiangdong Chen; Hua Tong; Jiming Hu
A new hybrid organic¢inorganic monolithic column for efficient deoxyribonucleic acid (DNA) extraction was prepared in situ by polymerization of N-(?-aminoethyl)-?-aminopropyltriethoxysilane (AEAPTES) and tetraethoxysilane (TEOS). The main extraction mechanism was based on the Coulombic force between DNA and the amino silica hybrid monolithic column. DNA extraction conditions, such as pH, ion concentration and type, and loading capacity, were optimized online by
... Society Pulse Oximetry amount of gases (oxygen and carbon dioxide) that are in your blood. To get ... Also, a pulse oximeter does not measure your carbon dioxide level. How accurate is the pulse oximeter? ...
Exponential frequency spectrum and Lorentzian pulses in magnetized plasmas
California at Los Angles, University of
Exponential frequency spectrum and Lorentzian pulses in magnetized plasmas D. C. Pace,a M. Shi, J the confinement magnetic field in a large plasma column are found to exhibit a broadband turbulence that displays been traced to the presence of solitary pulses having a Lorentzian temporal signature. These pulses
Compact electron beam focusing column
Persaud, Arun; Leung, Ka-Ngo; Reijonen, Jani
A novel design for an electron beam focusing column has been developed at LBNL. The design is based on a low-energy spread multicusp plasma source which is used as a cathode for electron beam production. The focusing column is 10 mm in length. The electron beam is focused by means of electrostatic fields. The column is designed for a maximum voltage of 50 kV. Simulations of the electron trajectories have been performed by using the 2-D simulation code IGUN and EGUN. The electron temperature has also been incorporated into the simulations. The electron beam simulations, column design and fabrication will be discussed in this presentation.
Technology Transfer Automated Retrieval System (TEKTRAN)
The concept of pulsed electric fields (PEF) was first proposed in 1967 to change the behavior or microorganisms. The electric field phenomenon was identified as membrane rupture theory in the 1980s. Increasing the membrane permeability led to the application of PEF assisted extraction of cellular co...
Employing anatomical knowledge in vertebral column labeling
NASA Astrophysics Data System (ADS)
Yao, Jianhua; Summers, Ronald M.
The spinal column constitutes the central axis of human torso and is often used by radiologists to reference the location of organs in the chest and abdomen. However, visually identifying and labeling vertebrae is not trivial and can be timeconsuming. This paper presents an approach to automatically label vertebrae based on two pieces of anatomical knowledge: one vertebra has at most two attached ribs, and ribs are attached only to thoracic vertebrae. The spinal column is first extracted by a hybrid method using the watershed algorithm, directed acyclic graph search and a four-part vertebra model. Then curved reformations in sagittal and coronal directions are computed and aggregated intensity profiles along the spinal cord are analyzed to partition the spinal column into vertebrae. After that, candidates for rib bones are detected using features such as location, orientation, shape, size and density. Then a correspondence matrix is established to match ribs and vertebrae. The last vertebra (from thoracic to lumbar) with attached ribs is identified and labeled as T12. The rest of vertebrae are labeled accordingly. The method was tested on 50 CT scans and successfully labeled 48 of them. The two failed cases were mainly due to rudimentary ribs.
Momentum spectra of electrons rescattered from rare-gas targets following their extraction by one- and two-color femtosecond laser pulses
Ray, D.; Chen Zhangjin; De, S.; Cao, W.; Le, A. T.; Lin, C. D.; Cocke, C. L. [J. R. Macdonald Laboratory, Physics Department, Kansas State University, Manhattan, Kansas 66506-2601 (United States); Litvinyuk, I. V. [J. R. Macdonald Laboratory, Physics Department, Kansas State University, Manhattan, Kansas 66506-2601 (United States); Centre for Quantum Dynamics, Griffith University, Nathan, Queensland 4111 (Australia); Kling, M. F. [J. R. Macdonald Laboratory, Physics Department, Kansas State University, Manhattan, Kansas 66506-2601 (United States); Max-Planck Institut fur Quantenoptik, D-85748 Garching (Germany)
We have used velocity-map imaging to measure the three-dimensional momenta of electrons rescattered from Xe and Ar following the liberation of the electrons from these atoms by 45 fs, 800 nm intense laser pulses. Strong structure in the rescattering region is observed in both angle and energy, and is interpreted in terms of quantitative rescattering (QRS) theory. Momentum images have also been taken with two-color (800 nm + 400 nm) pulses on Xe targets. A strong dependence of the spectra on the relative phase of the two colors is observed in the rescattering region. Interpretation of the phase dependence using both QRS theory and a full solution to the time-dependent Schroedinger equation shows that the rescattered electrons provide a much more robust method for determining the relative phase of the two colors than do the direct electrons.
Solid-phase extraction of galloyl- and caffeoylquinic acids from natural sources (Galphimia glauca and Arnicae flos) using pure zirconium silicate and bismuth citrate powders as sorbents inside micro spin columns.
Hussain, Shah; Sch÷nbichler, Stefan A; G³zel, Y³ksel; Sonderegger, Harald; Abel, Gudrun; Rainer, Matthias; Huck, Christian W; Bonn, G³nther K
Galloyl- and caffeoylquinic acids are among the most important pharmacological active groups of natural compounds. This study describes a pre-step in isolation of some selected representatives of these groups from biological samples. A selective solid-phase extraction (SPE) method for these compounds may help assign classes and isomer designations within complex mixtures. Pure zirconium silicate and bismuth citrate powders (325 mesh) were employed as two new sorbents for optimized SPE of phenolic acids. These sorbents possess electrostatic interaction sites which accounts for additional interactions for carbon acid moieties as compared to hydrophilic and hydrophobic sorbents alone. Based on this principle, a selective SPE method for 1,3,4,5-tetragalloylquinic acid (an anti-HIV and anti-asthamatic agent) as a starting compound was developed and then deployed upon other phenolic acids with success. The recoveries and selectivities of both sorbents were compared to most commonly applied and commercially available sorbents by using high performance liquid chromatography. The nature of interaction between the carrier sorbent and the acidic target molecules was investigated by studying hydrophilic (silica), hydrophobic (C18), mixed-mode (ionic and hydrophobic: Oasis(«) MAX) and predominantly electrostatic (zirconium silicate) materials. The newly developed zirconium silicate and bismuth citrate stationary phases revealed promising results for the selective extraction of galloyl- and caffeoylquinic acids from natural sources. It was observed that zirconium silicate exhibited maximum recovery and selectivity for tetragalloylquinic acid (84%), chlorogenic acid (82%) and dicaffeoylquinic acid (94%) among all the tested sorbents. PMID:23831490
Selected Topics in Column Generation
Marco E. L³bbecke; Jacques Desrosiers
Abstract Dantzig-Wolfe decomposition and column generation, devised for linear programs, is a success story in large scale integer programming. We outline and relate the approaches, and survey mainly recent contributions, not found in textbooks, yet. We emphasize on the growing understanding of the dual point of view, which brought considerable progress to the column generation theory and practice. It stimulated
Quantification of deoxynivalenol in wheat using an immunoaffinity column and liquid chromatography
Lisa M Cahill; Scott C Kruger; Brian T McAlice; Catherine S Ramsey; Reginaldo Prioli; Barb Kohn
A simple and accurate method to quantify the mycotoxin deoxynivalenol (DON) in wheat is described. The method uses immunoaffinity chromatography for DON isolation and liquid chromatography (LC) for toxin detection and quantification. Wheat samples are extracted in water, filtered twice and applied to an immunoaffinity column. Following a water wash, DON is eluted from the column with methanol and injected
Operational characteristics have been determined for fused silica capillary column (FSCC) GC/MS as applied to 'extractable' priority pollutants. Chromatographic data show excellent relative retention time (RRT) intralaboratory precision and interlaboratory accuracy when multiple ...
H. Lord
Pulse transformers capable of transmitting substantially rectangular voltage pulses, with durations of less than one microsecond, were developed for radar applications during World War II. Their primary functions were to match the impedances of high-power microwave radio-frequency electron-tube generators to electronic pulse generators and coaxial transmission cables, and to provide polarity reversal and impedance matching functions within pulse generator circuitry.
Jubran, Amal
Pulse oximetry is universally used for monitoring patients in the critical care setting. This article updates the review on pulse oximetry that was published in 1999 in Critical Care. A summary of the recently developed multiwavelength pulse oximeters and their ability in detecting dyshemoglobins is provided. The impact of the latest signal processing techniques and reflectance technology on improving the performance of pulse oximeters during motion artifact and low perfusion conditions is critically examined. Finally, data regarding the effect of pulse oximetry on patient outcome are discussed. PMID:26179876
Radiotracer Imaging of Sediment Columns
NASA Astrophysics Data System (ADS)
Moses, W. W.; O'Neil, J. P.; Boutchko, R.; Nico, P. S.; Druhan, J. L.; Vandehey, N. T.
Nuclear medical PET and SPECT cameras routinely image radioactivity concentration of gamma ray emitting isotopes (PET - 511 keV; SPECT - 75-300 keV). We have used nuclear medical imaging technology to study contaminant transport in sediment columns. Specifically, we use Tc-99m (T1/2 = 6 h, E? = 140 keV) and a SPECT camera to image the bacteria mediated reduction of pertechnetate, [Tc(VII)O4]- + Fe(II) ? Tc(IV)O2 + Fe(III). A 45 mL bolus of Tc-99m (32 mCi) labeled sodium pertechnetate was infused into a column (35cm x 10cm ž) containing uranium-contaminated subsurface sediment from the Rifle, CO site. A flow rate of 1.25 ml/min of artificial groundwater was maintained in the column. Using a GE Millennium VG camera, we imaged the column for 12 hours, acquiring 44 frames. As the microbes in the sediment were inactive, we expected most of the iron to be Fe(III). The images were consistent with this hypothesis, and the Tc-99m pertechnetate acted like a conservative tracer. Virtually no binding of the Tc-99m was observed, and while the bolus of activity propagated fairly uniformly through the column, some inhomogeneity attributed to sediment packing was observed. We expect that after augmentation by acetate, the bacteria will metabolically reduce Fe(III) to Fe(II), leading to significant Tc-99m binding. Imaging sediment columns using nuclear medicine techniques has many attractive features. Trace quantities of the radiolabeled compounds are used (micro- to nano- molar) and the half-lives of many of these tracers are short (<1 day). This allows multiple measurements to be made on the same column and thus the sediment biology to be monitored non-invasively over time (i.e. after an augmentation has been introduced) and minimizes long-lived radioactive waste. Different parameters can be measured, depending on the tracer type and delivery. A constant infusion of a conservative tracer, such as the positron emitter Br-76 (T1/2= 16.2 hr), measures the exclusion fraction (as a function of position in the column), while a bolus maps the flow velocity as a function of position. A tracer that interacts chemically with the contents of the column (e.g., [99m-Tc(VII)O4]- reduced to 99m-TcO2 by Fe(II) ) yields a map of the chemical environment (e.g., the distribution of Fe(II)). Image of Tc-99m distribution in a column containing Rifle sediment at four times.
Orthogonal screening system of columns for supercritical fluid chromatography.
West, C; Lesellier, E
The application of supercritical fluid chromatography is expanding nowadays, particularly in the pharmaceutical industry and for natural extracts. In order to select appropriate columns from the continuously increasing number of potentially suitable ones, a test that evaluates stationary phases properties, based on the solvation parameter model, was performed earlier. In this study, it is investigated whether the number of stationary phases can be reduced to an optimized set with only highly orthogonal systems. Such a set of orthogonal chromatographic systems having different selectivities may provide the initial separation for method development. Moreover, it was considered important to include systems with good overall separation performance in our final set. Thus the columns are also selected based on their ability to provide sharp and symmetric peaks. An example application based on the analysis of seven sunscreen molecules is presented as a validation of the suggested column set. PMID:18649886
Glycolipid class profiling by packed-column subcritical fluid chromatography.
Deschamps, Frantz S; Lesellier, Eric; Bleton, Jean; Baillet, Arlette; Tchapla, Alain; Chaminade, Pierre
The potential of packed-column subcritical fluid chromatography (SubFC) for the separation of lipid classes has been assessed in this study. Three polar stationary phases were checked: silica, diol, and poly(vinyl alcohol). Carbon dioxide (CO2) with methanol as modifier was used as mobile phase and detection performed by evaporative light scattering detection. The influence of methanol content, temperature, and pressure on the chromatographic behavior of sphingolipids and glycolipids were investigated. A complete separation of lipid classes from a crude wheat lipid extract was achieved using a modifier gradient from 10 to 40% methanol in carbon dioxide. Solute selectivity was improved using coupled silica and diol columns in series. Because the variation of eluotropic strength depending on the fluid density changes, a normalized separation factor product (NSP) was used to select the nature, the number and the order of the columns to reach the optimum glycolipid separation. PMID:15248431
Integrated column arithmetic according to progressive schematisation
A. Treffers
Following an introduction on the relation between column arithmetic and mental arithmetic in connection with the development of pocket calculators and computers, the characteristics of progressive schematisation are described with regard to column multiplication and column division. In this way, an image is formed of the specific characteristics of this approach to column arithmetic set against the background of traditional
Monolithic molecularly imprinted polymeric capillary columns for isolation of aflatoxins.
Szumski, Micha?; Grzywi?ski, Damian; Prus, Wojciech; Buszewski, Bogus?aw
Monolithic molecularly imprinted polymers extraction columns have been prepared in fused-silica capillaries by UV or thermal polymerization in a two-step process. First, a poly-(trimethylolpropane trimethacrylate) (polyTRIM) core monolith was synthesized either by UV or thermal polymerization. Then it was grafted with the mixture of methacrylic acid (MAA) as a functional monomer, ethylene dimethacrylate (EDMA) as a cross-linking agent, 5,7-dimethoxycoumarin (DMC) as an aflatoxin-mimicking template, toluene as a porogen solvent and 2,2-azobis-(2-methylpropionitrile) (AIBN) as an initiator of the polymerization reaction. Different thermal condition of the photografting and different concentrations of the grafting mixture were tested during polymerization. The extraction capillary columns were evaluated in the terms of their hydrodynamic and chromatographic properties. Retention coefficients for aflatoxin B1 and DMC were used for assessment of the selectivity and imprinting factor. The obtained results indicate that the temperature of photografting and concentration of the grafting mixture are key parameters that determine the quality of the prepared MIPs. From the MIP columns characterized by the highest permeability the column of the highest imprinting factor was applied for isolation of aflatoxins B1, B2, G1 and G2 from the model aqueous sample followed by on-line chromatographic separation. The process was performed using a micro-MISPE-microLC-LIF system of a novel design, which allowed for detection of the eluates from the sample preparation part as well as from the chromatographic separation. PMID:25218633
NASA Astrophysics Data System (ADS)
Stone, David H.
Pulsed power systems are critical elements for such prospective weapons technologies as high-power microwaves, electrothermal and electromagnetic projectile launchers, neutral particle beams, space-based FELs, ground-based lasers, and charged particle beams. Pulsed power will also be essential for the development of nonweapon military systems such as lidars and ultrawideband radars, and could serve as the bases for nuclear weapon effect simulators. The pulsed power generation requirements for each of these systems is considered.
Xylanase mass transfer studies in aqueous two-phase systems using spray and sieve plate columns
L. Igarashi; T. G. Kieckbusch; T. T. Franco
Aqueous two-phase systems (ATPSs) have long been used for biomolecule partitioning; these systems offer the possibility of using continuous or semicontinuous extraction processes. They require relatively simple equipment like spray or sieve plate columns that can be adapted for use in ATPSs. The aim of this work was to study the semicontinuous extraction of a model enzyme, xylanase, in spray
Method for liquid chromatographic extraction of strontium from acid solutions
Horwitz, E. Philip (Naperville, IL); Dietz, Mark L. (Evanston, IL)
A method and apparatus for extracting strontium and technetium values from biological, industrial and environmental sample solutions using a chromatographic column is described. An extractant medium for the column is prepared by generating a solution of a diluent containing a Crown ether and dispersing the solution on a resin substrate material. The sample solution is highly acidic and is introduced directed to the chromatographic column and strontium or technetium is eluted using deionized water.
Fluid Dynamic Experiments on Mush Column Magmatism
NASA Astrophysics Data System (ADS)
Flanagan-Brown, R. E.; Marsh, B. D.
A vertically extensive stack of sills interconnected by pipe-like conduits extending from the mantle through the lithosphere and capped by a volcanic center is a magmatic mush column. At any instant at various locations it contains fractionated and primitive melts as pools of nearly crystal-free magma, pools of crystal-rich magma, thick beds of cumulates, open conduits, and conduits congested by cognate and wall debris. All boundaries of the system are sheathed by solidification fronts. With the wide range of local, characteristic length scales there is a commensurate range of solidification time scales. This creates a complicated series of resistances to magma flow and provides a variety of distinct local physical environments for the chemical modification of magma. The system is driven by over-pressure from the addition of new melt from below. The over-pressure propagates upward by moving magma which flushes conduits, disrupts cumulate beds, and pools or purges sills. A critical aspect of this process is the entrainment, transport, and deposition of crystals throughout the system. Picritic lavas charges with entrained (tramp) olivine of a wide compositional range erupted at many systems (e.g. Jan Mayen, Kilauea, Reunion, etc.) are the final expression of this process. That the size and abundance of these crystals is correlated with eruptive flux (Murata & Richter, AJS, 1966) suggests an important indicator of the overall dynamics of the mush column. A mush column of this basic nature is observed is observed in the McMurdo Dry Valleys region of Antarctica and is inferred beneath Hawaii and the ocean ridges. We have attempted to model this process by studying the entrainment, transport, and deposition of particles in a vertical stack of sills (Plexiglas tanks) connected by resistive conduits (check valves), over-pressured from the base, and open at the top. The system is about two meters in height with water and oil as fluids and particles with Reynolds numbers that closely approximate actual crystals. Particles of a range of sizes are placed in the lower input pipe and carried by the fluid. The base state is a sustained over-pressure that permits a steady effusive flux throughout the system. To establish this state, the conduit resistance (check valve tension) must be overcome. As the critical moment of flow is approached, the system exudes a high-pitched vibration emanating from the check valves which may be akin to the well-known harmonic tremor of active volcanic systems. We also employ a time-series of over-pressure pulses, designed to mimic eruptive episodes of volcanism as estimated by Simkin (An. Rev. EPS, 1993). We observe many aspects of the process described above: particle deposition on sill floors forming beds around the conduits, cumulate piles disrupted by flux associated with over-pressure pulses, and flushing of choked conduits. The largest particle concentrations are in the basal sill and particle concentration decreases upward in the system. The magnitude and frequency of over-pressure pulses controls the ability of the system to erupt particles. Cumulate deposition is restricted to the conduit areas in each sill unless the flow is made to spread throughout the sill by horizontally separating the inflow and outflow conduits. Spreading flows, which form laterally graded cumulates, are also achieved by simulating outward lateral propagation of the sill via side-wall taps. The overall dynamic behavior of the system as understood so far suggests that the time history of the cumulate eruptive flux, as measured by crystal size, abundance, and composition, may carry enough information to critically evaluate the deep plumbing and dynamics of many magmatic-volcanic systems.
Isotope Enrichment in a Fully Ionized, Rotating Metal Plasma Column.
NASA Astrophysics Data System (ADS)
Geva, Michael
In 1971 Bonnevier('1) demonstrated experimentally isotopic. separation in a rotating neon plasma column. Since then much. study has been conducted of the mass separation in a plasma. centrifuge, and enrichment has been shown in a variety of plasmas. In these studies the plasma was either partially ionized or. surrounded by a neutral gas. The neutral particles limited the. achievable separation by slowing down the rotation below the. Alfven critical velocity or by dragging the rotating ions and causing. turbulence which smeared out the stratification. In this thesis, an. experimental study is presented, of a pure, fully ionized rotating. plasma column, produced in a laser-initiated vacuum arc in an axial. magnetic field. The plasma column was surrounded by a vacuum,. thus avoiding the deleterious effect of the neutral particles. Experiments are reported, in which various properties of the plasma. centrifuge were studied under a variety of conditions. Plasma. columns of C, Cu, Cu-Ni, Al-Ti, Dc-Sn and others were investigated. The discharge was pulsed, of milliseconds duration, with peak. currents of several kiloamps, in axial magnetic fields of up to 3.7kG. The study included characteristics of the vacuum arc in an axial. magnetic field, the rotation of the plasma column, the radial electric. field in the column, and the radial and axial dependence of the. plasma density and of the centrifugal mass separation. The. measurements showed a radial density of roughly a Gaussian. profile, with peak values of about 10('13)cm(' -3) and of FWHM of 4-6cm. The plasma column exhibited a solid body rotation, at an angular. frequency of (TURN)10('5) rad/sec. The radial electric field in the column. was linearly dependent on the radius and had values of typically. several volts/cm, indicating the column rotational velocities to be. close to the ExB drift. Mass separation of about 80% were measured. in Cu-Ni and ('65)Cu-('63)Cu, and of 20% in Sn -Cd. In Al-Ti plasma, the. relative abundance of the Al, whose mass to charge ratio was higher. than that of the Ti, was 4 times higher at r = 3cm than at the center. The axial evolution of the radial density and enrichment profiles. showed a strong axial dependence near the cathode which became. rather weak at about 1m from the cathode. Based on this behavior. an analytical model was developed of a plasma centrifuge in a. quasi-equilibrium steady-state, and was compared to the experimental results. ('1)B. Bonnevier, Plasma Physics, 13, 763 (1971).
Gravitational light bending near neutron stars. I. Emission from columns and hot spots
Riffert, H.; Meszaros, P.
The beam shapes, pulse profiles, and spectral transmission function at infinity for the radiation originating in columns or hot spots on slowly rotating neutron stars, represented by the Schwarzschild metric, are calculated. These are used for models for binary accreting pulsars and may apply to isolated neutron stars as well. The shadowing effects and their interplay with the frequency changes as a function of the observer angle are discussed. The observed bolometric beam shapes and pulse profiles are given as a function of radius, as well as observed pulse-phase spectra and frequency-dependent pulse profiles, for various types of source functions at the surface. The more realistic accretion (or emission) column geometry used indicates that these may show a larger degree of modulation than was previously thought, as compared to hot spots. The observational implications for X-ray-emitting pulsars are discussed. 24 references.
Comparison of a Multipore Column with a Mixed-Bed Column for Size Exclusion Chromatography
M. Nagata; T. Kato; H. Furutani
A new type of column packed with polystyrene gels which have a broad pore size distribution in a particle (henceforth referred to as the multipore column) was developed, and its performance was compared with the so-called linear column (henceforth referred to as the mixed-bed column). The chromatogram of the epoxy resin (Epikote 1009) on the multipore column showed a monomodal
Selected Topics in Column Generation
Dec 2, 2002 ... efficient heuristic algorithm for solving the cutting stock problem. ... of linear programming column generation, expanding respectively on the strategies developed for get- ... multiple traveling salesman problem with time windows .... as convex combination of extreme points {pq}q?Q plus non-negativeĀ...
Editorial: Research and Teaching Column
NSDL National Science Digital Library
Marcy Towns
The JCST Research and Teaching column will feature sound research on curriculum, pedagogy, and student learning at the college level. Topics of interest include all fields of science: chemistry, biology, geology, astronomy, physics, geography, mathematics, environmental science, and computer science. Studies that are interdisciplinary or are readily applicable to several disciplines in the sciences are also of interest.
Paris-Sud XI, Universitķ de
93/0096 WASTEWATER TREATMENT OVER SAND COLUMNS TREATMENT YIELDS, LOCALISATION OF THE BIOMASS Domestic wastewater treatment by infiltration-percolation is a process that becomming common in France, a greater depth for desinfection purposes. KEYWORDS Wastewater treatment, Infiltration-percolation. Sand
Effects of a malfunctional column on conventional and FeedCol-simulated moving bed chromatography performance.
Song, Ji-Yeon; Oh, Donghoon; Lee, Chang-Ha
The effects of a malfunctional column on the performance of a simulated moving bed (SMB) process were studied experimentally and theoretically. The experimental results of conventional four-zone SMB (2-2-2-2 configuration) and FeedCol operation (2-2-2-2 configuration with one feed column) with one malfunctional column were compared with simulation results of the corresponding SMB processes with a normal column configuration. The malfunctional column in SMB processes significantly deteriorated raffinate purity. However, the extract purity was equivalent or slightly improved compared with the corresponding normal SMB operation because the complete separation zone of the malfunctional column moved to a lower flow rate range in zones II and III. With the malfunctional column configuration, FeedCol operation gave better experimental performance (up to 7%) than conventional SMB operation because controlling product purity with FeedCol operation was more flexible through the use of two additional operating variables, injection time and injection length. Thus, compared with conventional SMB separation, extract with equivalent or slightly better purity could be produced from FeedCol operation even with a malfunctional column, while minimizing the decrease in raffinate purity (less than 2%). PMID:26037316
Capacitor discharge pulse analysis.
Baker, Michael Sean; Griffiths, Stewart K.; Tanner, Danelle Mary
Capacitors used in firing sets and other high discharge current applications are discharge tested to verify performance of the capacitor against the application requirements. Parameters such as capacitance, inductance, rise time, pulse width, peak current and current reversal must be verified to ensure that the capacitor will meet the application needs. This report summarizes an analysis performed on the discharge current data to extract these parameters by fitting a second-order system model to the discharge data and using this fit to determine the resulting performance metrics. Details of the theory and implementation are presented. Using the best-fit second-order system model to extract these metrics results in less sensitivity to noise in the measured data and allows for direct extraction of the total series resistance, inductance, and capacitance.
"Supermarket Column Chromatography of Leaf Pigments" Revisited: Simple and Ecofriendly Separation of Plant Carotenoids, Chlorophylls, and Flavonoids from Green and Red Leaves
ERIC Educational Resources Information Center
Dias, Alice M.; Ferreira, Maria La Salete
A simple and ecofriendly procedure was developed in order to prepare extracts from red and green leaves. This procedure enables the separation of yellow, green, and red band pigments and optimizes the previously reported baking soda "supermarket column". The same extract also led to a novel and colorful potato starch column, which canģ
Antibacterial activity of grapefruit ( Citrus paradisi ) peel extracts
P. S. Negi; G. K. Jayaprakasha
Citrus paradisi peels were successively extracted with hexane, chloroform, acetone and methanol using a Soxhlet extractor for 8 h each. Thin layer chromatography (TLC) of hexane and chloroform extracts showed three spots with different concentrations; hence both the extracts were mixed and fractionated into alcohol soluble and insoluble fractions. Naringin was isolated from acetone and methanol extracts by column chromatography
The Desulfurization of Fluid Catalytic Cracking Gasoline by Extractive Distillation
H. Shen; Z. Mei; B. Shen; H. Ling
Desulfurization of fluid catalytic cracking gasoline was investigated in a lab scale extractive distillation column. Before the extractive distillation, fluid catalytic cracking gasoline was distillated into light and heavy fractions. Then, the light fraction was desulfurized by extractive distillation using dimethylformamide as the solvent. Factors impacting the desulfurization efficiency of the extractive distillation were studied. Under optimal desulfurization conditions, distillate
Ultra-short ion and neutron pulse production
Leung, Ka-Ngo; Barletta, William A.; Kwan, Joe W.
An ion source has an extraction system configured to produce ultra-short ion pulses, i.e. pulses with pulse width of about 1 .mu.s or less, and a neutron source based on the ion source produces correspondingly ultra-short neutron pulses. To form a neutron source, a neutron generating target is positioned to receive an accelerated extracted ion beam from the ion source. To produce the ultra-short ion or neutron pulses, the apertures in the extraction system of the ion source are suitably sized to prevent ion leakage, the electrodes are suitably spaced, and the extraction voltage is controlled. The ion beam current leaving the source is regulated by applying ultra-short voltage pulses of a suitable voltage on the extraction electrode.
Effect of drillstring vibrations on MWD pressure pulse signals
Lear, W.E.; Dareing, D.W. (Florida Univ., Gainesville, FL (USA). Dept. of Mechanical Engineering)
Axial vibrations of drillstrings produce pressure variations within the drilling fluid column. These pressure variations are imposed on controlled pressure pulse signals from measurement-while-drilling (MWD) tools producing background noise in pressure pulse data measured at the rig. The paper shows the effect on signal-to-noise ratio for various operating conditions, such as vibration frequency, valve opening/closing time, pulsing interval, and flow rate.
Supercritical fluid extraction on semibatch mode for the removal of terpene in citrus oil
Masaki Sato; Motonobu Goto; Tsutomu Hirose
Supercritical carbon dioxide extraction of a mixture of limonene and linalool was carried out with a rectification column in the semibatch operation mode. For the simple semibatch extraction where the column was controlled at the uniform temperature without an internal reflux, the Rayleigh equation, developed for the simple batch distillation, was applied to express the dynamic extraction behavior. In this
Object extraction Object extraction
Giger, Christine
(is a grass-roof a vegetation area?) Ę object ontologies are hierarchical (tree / forrest / vegetation Ę buildings Ę vegetation Ę roads #12;Interactive object extraction #12;Interactive object extraction angles in man-made structures Ę measurement accuracy of human operator is lower than that of automatic
Water Column Methylation in Estuaries
NASA Astrophysics Data System (ADS)
Schartup, A. T.; Calder, R.; Soerensen, A. L.; Mason, R. P.; Balcom, P. H.; Sunderland, E. M.
Methylmercury (MeHg) is a neurotoxin that bioaccumulates in aquatic food webs and affects humans and wildlife through fish consumption. Many studies have measured active methylation/demethylation in ocean margin sediments but few have reported similar rates for the marine water column. This presentation will review available evidence for water column methylation in estuaries, including new experimental measurements of methylation/demethylation rates from a deep subarctic fjord in Labrador Canada collected in Spring and Fall of 2012-2013. We used these and other data to construct a mass budget for MeHg in the estuary and show that water column methylation (with rates ranging from 1.5 to 2.8 % day-1), is the largest contributor, followed by inputs from rivers (4.9 mol year-1), to the in situ pool of MeHg available for uptake by biota. By contrast, the sediment in this system is a net sink for MeHg (-1.5 mol year-1). We discuss the relationship between observed MeHg and other ancillary environmental factors (organic carbon, sulfur and nutrients) as well as implications for the response time of fish to future changes in mercury inputs.
29 CFR 1926.755 - Column anchorage.
Code of Federal Regulations, 2014 CFR
...anchored by a minimum of 4 anchor rods (anchor bolts). (2) Each column anchor rod (anchor bolt) assembly, including the column-to-base...field modification of anchor rods (anchor bolts). (1) Anchor rods (anchor bolts)...
29 CFR 1926.755 - Column anchorage.
Code of Federal Regulations, 2011 CFR
...anchored by a minimum of 4 anchor rods (anchor bolts). (2) Each column anchor rod (anchor bolt) assembly, including the column-to-base...field modification of anchor rods (anchor bolts). (1) Anchor rods (anchor bolts)...
29 CFR 1926.755 - Column anchorage.
Code of Federal Regulations, 2010 CFR
...anchored by a minimum of 4 anchor rods (anchor bolts). (2) Each column anchor rod (anchor bolt) assembly, including the column-to-base...field modification of anchor rods (anchor bolts). (1) Anchor rods (anchor bolts)...
29 CFR 1926.755 - Column anchorage.
Code of Federal Regulations, 2013 CFR
...anchored by a minimum of 4 anchor rods (anchor bolts). (2) Each column anchor rod (anchor bolt) assembly, including the column-to-base...field modification of anchor rods (anchor bolts). (1) Anchor rods (anchor bolts)...
29 CFR 1926.755 - Column anchorage.
Code of Federal Regulations, 2012 CFR
...anchored by a minimum of 4 anchor rods (anchor bolts). (2) Each column anchor rod (anchor bolt) assembly, including the column-to-base...field modification of anchor rods (anchor bolts). (1) Anchor rods (anchor bolts)...
FRP rupture strains in FRP wrapped columnsĀ
Li, Shiqing
Applying lateral confinement to concrete columns using fibre-reinforced polymer (FRP) composites is a very promising technique. FRP rupture is the typical failure mode of FRP wrapped columns under axial compression. numerous ...
David H. Stone
Pulsed power systems are critical elements for such prospective weapons technologies as high-power microwaves, electrothermal and electromagnetic projectile launchers, neutral particle beams, space-based FELs, ground-based lasers, and charged particle beams. Pulsed power will also be essential for the development of nonweapon military systems such as lidars and ultrawideband radars, and could serve as the bases for nuclear weapon effect simulators.
Handling of Environmental and Biological Samples via PreColumn Technologies
R. W. Frei; M. W. F. Nielen; U. A. Th. Brinkman
Sample handling is still a weak point in chromatography and in analytical chemisty in general. One consideration is the automation potential of new procedures. Solid-liquid extraction techniques in combination with pre-column technology are particularly promising in this regards. The construction and geometry of pre-columns both for conventional and narrow-bore HPLC are of major importance, since band broadening should be kept
SIGACT news complexity theory column 34
This issue's guest columnists are angels. The column was faced with a last-minute cancellation, and they prepared on very short notice a wonderful column. And I'm sure that many readers of the column will want to learn even more by, for example, reading their monograph Complexity Classifications of Boolean Constraint Satisfaction Problems [7].Future complexity columns include Holzer\\/McKenzie on a familiar
Horton, James A. (Livermore, CA)
Apparatus (20) for increasing the length of a laser pulse to reduce its peak power without substantial loss in the average power of the pulse. The apparatus (20) uses a White cell (10) having a plurality of optical delay paths (18a-18d) of successively increasing number of passes between the field mirror (13) and the objective mirrors (11 and 12). A pulse (26) from a laser (27) travels through a multi-leg reflective path (28) between a beam splitter (21) and a totally reflective mirror (24) to the laser output (37). The laser pulse (26) is also simultaneously injected through the beam splitter (21) to the input mirrors (14a-14d) of the optical delay paths (18a-18d). The pulses from the output mirrors (16a-16d) of the optical delay paths (18a-18d) go simultaneously to the laser output (37) and to the input mirrors ( 14b-14d) of the longer optical delay paths. The beam splitter (21) is 50% reflective and 50% transmissive to provide equal attenuation of all of the pulses at the laser output (37).
Determination of basic drugs of abuse in human serum by online extraction and LC¢MS\\/MS
Nerea Ferreir¾s Bouzas; Sebastian Dresen; Barbara Munz; Wolfgang Weinmann
A new quantitation method for the determination of drugs of abuse (opiates, amphetamine and derivatives, cocaine, methadone\\u000a and metabolites) in serum by using online extraction coupled to liquid chromatography (LC)¢mass spectrometry (MS)\\/MS has been\\u000a developed. The online extraction is carried out using two extraction columns simultaneously and one analytical column. One\\u000a extraction column is loaded, while the other one is
Purification of polar compounds from Radix isatidis using conventional C18 column coupled with polar-copolymerized C18 column.
Zeng, Jing; Guo, Zhimou; Xiao, Yuansheng; Wang, Chaoran; Zhang, Xiuli; Liang, Xinmiao
Regarding hydrophilic interaction chromatography and normal phase liquid chromatography, RPLC is another choice used to separate polar compounds with the improvement of polar-modified C18 stationary phase. In this study, a method using conventional C18 column coupled with polar-copolymerized C18 column was successfully developed for the separation and purification of polar compounds from Radix isatidis, which is one of the most commonly used traditional Chinese medicines (TCMs). An XTerra MS C18 column was used to fractionate the extract of R. isatidis and a homemade polar-copolymerized C18 column was utilized for the final purification due to its good separation selectivity and high resolution for polar compounds. The established purification system demonstrated good orthogonality for the polar compounds. As a result, ten compounds were purified and three of them were identified as 3-methyl-5-vinyloxazolidin-2-one (compound A), 5-hydroxymethyl-2-furaldehyde (compound B) and 3-methylfuran-2-carboxylic acid (compound G) based on the MS, IR and extensive NMR data, respectively. It was demonstrated to be a feasible and powerful technique for the purification of polar compounds under RPLC mode and more chemical information of TCMs will be obtained to interpret the efficiency of TCMs. PMID:20886519
Corrosion characterisation using pulsed eddy current sensor systems
Guiyun Tian; Yunze He; Mohammed Alamin; Hong Zhang; Paul Jackson
Pulsed Eddy Current (PEC) has been applied to characterise atmospheric corrosion on steel samples. Coated and uncoated mild steel (S275) samples with different marine atmospheric corrosion have been supplied by International Paint«. After introduction of pulsed eddy current systems, different measurement on different samples have been undertaken. Experimental results using pulsed eddy current sensor systems and feature extraction on corrosion
Dry-Column Flash Chromatography
NASA Astrophysics Data System (ADS)
Shusterman, Alan J.; McDougal, Patrick G.; Glasfeld, Arthur
Dry-column flash chromatography is a safe, powerful, yet easily learned preparative chromatography technique. It has proven useful in research, and an adaptation of the technique for use in large teaching laboratories (general chemistry, organic chemistry) is described here. The student version is similar to vacuum filtration, uses the same compact, readily available glassware, and inexpensive and safe solvents (ethyl acetate and hexane) and adsorbent (Merck grade 60 silica gel). The technique is sufficiently simple and powerful that a beginning student can successfully resolve diastereomers on sample scales ranging from 100 mg to >1 g.
A novel method for characterization and comparison of reversed-phase column selectivity.
Wang, Jixia; Wang, Chaoran; Guo, Zhimou; Dong, Xuefang; Xiao, Yuansheng; Xue, Xingya; Zhang, Xiuli; Liang, Xinmiao
Characterization of reverse-phase column selectivity is helpful for chromatographers to select an optimal column. A novel method, based on linear solvation energy relationships (LSERs) combined with fundamental retention equations, was developed to characterize and compare reversed-phase column selectivity. The retention times of 25 elaborately selected solutes on 12 reversed-phase columns were determined in three linear gradient elutions. Using these retention times, fundamental retention equations were acquired by a complex sample analysis software system (CSASS). When 0%, 10%, 20%, 30%, 40% and 50% acetonitrile were introduced into the fundamental retention equations, the corresponding retention factors were predicted and used to obtain LSER equations by multiple linear regression. In the gradient elution, the retention times of solutes could be accurately determined and the excessively long or short analysis time could be avoided. As the retention factor (lnkw) at a hypothetical 0% organic modifier closely reflected properties of columns, coefficients of LSERs equations obtained based on lnkw were employed to discuss the properties of different stationary phases. An angle and a spider diagram based on solvation energy vectors were used to compare selectivity differences between stationary phases, which provided a visual means for users to select appropriate columns with orthogonal or similar selectivity. These results of column selectivities were compared with those obtained by geometric orthogonality approach, and a consistent result was acquired. Finally, Click TE-CD and XCharge C18PN with highest difference in column selectivity were applied to the separation of Psoralea corylifolia extraction. PMID:25155063
Determination of tadalafil in pharmaceutical preparation by HPLC using monolithic silica column
Hassan Y. Aboul-Enein; Imran Ali
The simple, reliable and reproducible HPLC and extraction methods were developed for the analysis of tadalafil in pharmaceutical preparation. The column used was monolithic silica column, Chromolith Performance RP-18e (100mm ū 4.6mm, i.d.). The mobile phase used was phosphate buffer (100mM, pH 3.0)-acetonitrile (80:20, v\\/v) at the flow rate of 5mLmin?1 with UV detection at 230nm at ambient temperature. Extraction
Enzyme activities in the water column and in shallow permeable sediments from the northeastern Gulf of Mexico
NASA Astrophysics Data System (ADS)
Arnosti, C.; Ziervogel, K.; Ocampo, L.; Ghobrial, S.
The activities of extracellular enzymes that initiate the microbial remineralization of high molecular weight organic matter were investigated in the water column and sandy surface sediments at two sites in the northeastern Gulf of Mexico. Six fluorescently labeled polysaccharides were hydrolyzed rapidly in the water column as well as in permeable sediments. This result contrasts with previous studies carried out in environments dominated by fine-grained muds, in which the spectrum of enzymes active in the water column is quite limited compared to that of the underlying sediments. Extracts of Spirulina, Isochrysis, and Thalassiosira were also used to measure hydrolysis rates in water from one of the sites. Rates of hydrolysis of the three plankton extracts were comparable to those of the purified polysaccharides. The broad spectrum and rapid rates of hydrolysis observed in the water column at both sites in the northeastern Gulf of Mexico may be due to the permeable nature of the sediments. Fluid flux through the sediments is sufficiently high that the entire 1.5 m deep water column could filter though the sediments on timescales of a few days to two weeks. Movement of water through sediments may also transport dissolved enzymes from the sediment into the water column, enhancing the spectrum as well as the rate of water column enzymatic activities. Such interaction between the sediments and water column would permit water column microbial communities to access high molecular weight substrates that might otherwise remain unavailable as substrates.
Soil column leaching of pesticides.
Katagi, Toshiyuki
In this review, I address the practical and theoretical aspects of pesticide soil mobility.I also address the methods used to measure mobility, and the factors that influence it, and I summarize the data that have been published on the column leaching of pesticides.Pesticides that enter the unsaturated soil profile are transported downwards by the water flux, and are adsorbed, desorbed, and/or degraded as they pass through the soil. The rate of passage of a pesticide through the soil depends on the properties of the pesticide, the properties of the soil and the prevailing environmental conditions.Because large amounts of many different pesticides are used around the world, they and their degradates may sometimes contaminate groundwater at unacceptable levels.It is for this reason that assessing the transport behavior and soil mobility of pesticides before they are sold into commerce is important and is one indispensable element that regulators use to assess probable pesticide safety. Both elementary soil column leaching and sophisticated outdoor lysimeter studies are performed to measure the leaching potential for pesticides; the latter approach more reliably reflects probable field behavior, but the former is useful to initially profile a pesticide for soil mobility potential.Soil is physically heterogeneous. The structure of soil varies both vertically and laterally, and this variability affects the complex flow of water through the soil profile, making it difficult to predict with accuracy. In addition, macropores exist in soils and further add to the complexity of how water flow occurs. The degree to which soil is tilled, the density of vegetation on the surface, and the type and amounts of organic soil amendments that are added to soil further affect the movement rate of water through soil, the character of soil adsorption sites and the microbial populations that exist in the soil. Parameters that most influence the rate of pesticide mobility in soil are persistence (DT50) of the pesticide, and its sorption/desorption(Koc) characteristics. These parameters may vary for the same pesticide from geographic site-to-site and with soil depth. The interactions that normally occur between pesticides and dissolved organic matter (DOM) or WDC are yet other factors that may complicate pesticide leaching behavior.The soil mobility of pesticides is normally tested both in the laboratory and in the field. Lab studies are initially performed to give researchers a preliminary appraisal of the relative mobility of a pesticide. Later, field lysimeter studies can be performed to provide more natural leaching conditions that emulate the actual field use pattern. Lysimeter studies give the most reliable information on the leaching behavior of a pesticide under field conditions, but these studies are time-consuming and expensive and cannot be performed everywhere. It is for this reason that the laboratory soil column leaching approach is commonly utilized to profile the mobility of a pesticide,and appraise how it behaves in different soils, and relative to other pesticides.Because the soil structure is chemically and physically heterogenous, different pesticide tests may produce variable DT50 and Koc values; therefore, initial pesticide mobility testing is undertaken in homogeneously packed columns that contain two or more soils and are eluted at constant flow rates. Such studies are done in duplicate and utilize a conservative tracer element. By fitting an appropriate mathematical model to the breakthrough curve of the conservative tracer selected,researchers determine key mobility parameters, such as pore water velocity, the column-specific dispersion coefficient, and the contribution of non equilibrium transport processes. Such parameters form the basis for estimating the probable transport and degradation rates that will be characteristic of the tested pesticide. Researchers also examine how a pesticide interacts with soil DOM and WDC, and what contribution from facilitated transport to mobility is made as a result of the effects of
Pulsed Operation of an Ion Accelerator
NASA Technical Reports Server (NTRS)
Wirz, Richard; Gamero-Castano, Manuel; Goebel, Dan
Electronic circuitry has been devised to enable operation of an ion accelerator in either a continuous mode or a highpeak power, low-average-power pulsed mode. In the original intended application, the ion accelerator would be used as a spacecraft thruster and the pulse mode would serve to generate small increments of impulse for precise control of trajectories and attitude. The present electronic drive circuitry generates the extraction voltage in pulses. Pulse-width modulation can affect rapid, fine control of time-averaged impulse or ion flux down to a minimum level much lower than that achievable in continuous operation.
Comparison of Several Extraction Methods for the Isolation of Benzoic Acid Derivatives from Melissa officinalis
Gabriela Karasovß; Jozef Lehotay; Ewa K?odzinska; Bogus?aw Buszewski
Several extraction techniques, such as Soxhlet extraction, solid phase extraction using molecularly imprinted polymer, matrix solid phase dispersion, and supercritical fluid extraction were evaluated for the isolation and purification of phenolic compounds, e.g., benzoic acids from natural samples of Melissa officinalis. The extracts of benzoic acids were analyzed by high performance liquid chromatography (HPLC) in reversed phase modus (C18 column)
High-energy subnanosecond pulse amplification in XeCl
NASA Technical Reports Server (NTRS)
Pacala, T. J.; Laudenslager, J. B.; Christensen, C. P.
Pulse slicing and two-pass amplification are investigated as a means of producing high-energy subnanosecond pulses in the near ultraviolet. A simple laboratory-scale XeCl oscillator-Pockels cell pulse slicer-amplifier system is used to produce 50-mJ pulses of subnanosecond duration at 308 nm. Comparison of multinanosecond and subnanosecond pulse amplification allows estimation of the amplifier energy storage time to be 5 ns and demonstrates nearly complete extraction of available stored energy by the subnanosecond pulse.
High-energy subnanosecond pulse amplification in XeCl
Pacala, T.J.; Laudenslager, J.B.; Christensen, C.P.
Pulse slicing and two-pass amplification are investigated as a means of producing high-energy subnanosecond pulses in the near ultraviolet. A simple laboratory-scale XeCl oscillator--Pockels cell pulse slicer--amplifier system is used to produce 50-mJ pulses of subnanosecond duration at 308 nm. Comparison of multinanosecond and subnanosecond pulse amplification allows estimation of the amplifier energy storage time to be 5 ns and demonstrates nearly complete extraction of available stored energy by the subnanosecond pulse.
Short communication: Amino trap column improves the separation of methylimidazoles, 5-hydroxymethyl-2-furaldehyde, and sugars in Maillard reaction.
Xu, Xian-Bing; Liu, Ding-Bo; Yu, Shu-Juan; Zhao, Zhen-Gang; Yu, Pei
A simultaneous analysis of methylimidazoles, reducing sugars, and 5-hydroxymethyl-2-furaldehyde in the Maillard reaction was improved by use of an amino trap column. Analysis was carried out by using high-performance anion exchange chromatography with pulsed amperometric detection (HPAEC-PAD) coupled with an amino trap column. The amino trap column was a useful tool to improve the separation of methylimidazoles, reducing sugars, and 5-hydroxymethyl-2-furaldehyde. This technique is useful for simultaneous analysis of methylimidazoles, reducing sugars, and 5-hydroxymethyl-2-furaldehyde in risk assessment for dairy products. PMID:25200783
Non-ductile response of structural elements, particularly columns, has been the cause of numerous documented failures during earthquakes. The objective of this experimental study was to evaluate the non-linear behaviour of non-ductile reinforced concrete short columns under lateral cyclic deformations and to evaluate rehabilitation schemes. Three reinforced concrete short columns were tested under cyclic lateral loads and constant axial load. The
Urine from cigarette smokers was prepared for mutagenicity testing by extracting mutagens with solid phase extraction columns. ommercially available prepacked bonded silicas (cotadecyl, cyclohexyl, cyanopropyl) were compared for their efficiency and specificity in concentration o...
Table I. Column 4, labelled f, lists isotopic abundance fractions from Anders and Grevesse [11]. Columns 5 through 7 are from Table of Isotopes [12]. Column
Kurucz, Robert L.
Table I. Column 4, labelled f, lists isotopic abundance fractions from Anders and Grevesse [11]. Columns 5 through 7 are from Table of Isotopes [12]. Column 5, labelled I, is the nuclear spin. Column 6, labelled », is the magnetic dipole moment in nuclear magnetons. Column 7, labelled Q, is the electric
Bohachevsky, I.O.; Torrey, M.D.
An underwater pulsed hydrojet propulsion system is provided for accelerating and propelling a projectile or other vessel. A reactant, such as lithium, is fluidized and injected into a water volume. The resulting reaction produces an energy density in a time effective to form a steam pocket. Thrust flaps or baffles direct the pressure from the steam pocket toward an exit nozzle for accelerating a water volume to create thrust. A control system regulates the dispersion of reactant to control thrust characteristics.
Purification of C70 using charcoal as a stationary phase in a flash chromatography column
NASA Astrophysics Data System (ADS)
Scrivens, W. A.; Cassell, A. M.; Kinsey, K. E.; Tour, J. M.
Described is a method for the purification of C60 and C70 using a flash chromatography column that contains charcoal as the stationary phase. A number of functionalized aromatic solvents are studied and their efficacy for extraction, NMR spectral acquisition, and chromatographic purification of fullerenes is discussed. Ortho-dichlorobenzene was chosen as the best solvent for these applications and examples of its use in the extraction of higher fullerenes (greater than C84) and in the rapid acquisition of C-13 NMR spectra are given. Finally, single column purification of both C60 and C70 is discussed. Starting with a typical arc-derived mixture of soluble fullerenes, 5.97 g of C60 at greater than 99.9 percent purity and 1.58 g of C70 at greater than 97 percent purity were produced in a single column pass.
Xylanase mass transfer studies in aqueous two-phase systems using spray and sieve plate columns.
Igarashi, L; Kieckbusch, T G; Franco, T T
Aqueous two-phase systems (ATPSs) have long been used for biomolecule partitioning; these systems offer the possibility of using continuous or semicontinuous extraction processes. They require relatively simple equipment like spray or sieve plate columns that can be adapted for use in ATPSs. The aim of this work was to study the semicontinuous extraction of a model enzyme, xylanase, in spray and sieve plate columns, since, unlike centrifugal contactors, the cost of construction and maintenance of this equipment is low and it is easy to operate. For the spray column, the dispersed phase hold-up and overall mass transfer coefficients K(D) a were evaluated for different column heights and for different superficial velocities of the dispersed phase (light phase). Results indicated that an increase in superficial velocity in the range of 0-0.18 mm/s of the dispersed phase had a positive effect on K(D) a and on hold-up in all column heights studied, 75, 161 and 246 mm. For the same superficial velocity of the dispersed phase, the larger the hold-up was, the shorter the column. For the sieve plate column, the effects of the superficial velocity of the dispersed phase and the number of plates were also studied. Results showed that the K(D) a and hold-up increased with an increase in both parameters. The selectivity of separation of xylanase and BSA (model contaminant) was very high, since 60% of the enzyme was extracted in the light phase, whereas no significant amount of BSA was extracted. The possibility of using the sieve plate column in continuous operation for enzyme extraction was studied because previous work had only addressed the semicontinuous extraction of enzyme. The residence time distribution of the PEG phase using different superficial velocities of the salt phase was studied in continuous operation. The time required to reach the steady state was 40 min, and 70% of the xylanase was recovered. It was found that the Modified Power Spline software was well adjusted to the experimental results. PMID:14986093
Determination of ochratoxin A at the ppt level in human blood, serum, milk and some foodstuffs by high-performance liquid chromatography with enhanced fluorescence detection and immunoaffinity column cleanup: methodology and Swiss data
Bernhard Zimmerli; Rudolf Dick
An improved specific analytical method for ochratoxin A (OA) is presented, combining HPLC separation with enhanced fluorescence detection by post-column addition of ammonia. Commercial immunoaffinity columns (Biocode) were for the first time applied to the cleanup of extracts of body fluids; they could be used up to 20 times for blood serum. The extraction efficiency of OA from human serum
The development of HPLC columns: Packing structure, column efficiency, stability and standardization
Unger, K.K.; Hallman, M.; Ranis-Jansen, R. [Johannes Gutenberg-Universitat, Mainz (Germany)
Packing procedures for HPLC columns, such as the slurry technique (analytical columns) and the axial compression technique (preparative columns) have been widely established. However, there is still a lack of fundamental knowledge concerning the actual packing structure of a column and its impact on efficiency and stability. Recently, attempts have been made to model the packing procedure as well as the column bed structure and to apply experimental methods to characterize the assembly of microparticles in a column and the elution profiles in situ. The high reproducibility of commercial HPLC columns with respect to efficiency is mainly due to the substantial improvements made in particle technology, column hardware and optimized column packing procedures. The stability of commercial columns is acceptable but very much dependent on the extent of sample clean-up and the column handling and operation by the user. To validate HPLC methods, a project is planned to establish a C18 reversed phase reference column for standardization and certification in the frame of the EC Programme on {open_quotes}Measurements and Testing{open_quotes}.
Chart 1 (350 characters) (1) c 2008729 : column 1 = simplified character, column 2 = traditional character
Roegel, Denis
2008729 #12;2 #12;Chart 1 (350 characters) (1) c 2008729 : column 1 = simplified character will hopefully be resolved in the future) 3 #12;4 #12;Chart 1 (350 characters) (2) 5 #12;6 #12;Chart 1 (350 characters) (3) c 2008729 : column 1 = simplified character, column 2
Circulation in gas-slurry column reactors
Clark, N.; Kuhlman, J.; Celik, I.; Gross, R.; Nebiolo, E.; Wang, Yi-Zun.
Circulation in bubble columns, such as those used in fischer-tropsch synthesis, detracts from their performance in that gas is carried on average more rapidly through the column, and the residence time distribution of the gas in the column is widened. Both of these factors influence mass-transfer operations in bubble columns. Circulation prediction and measurement has been undertaken using probes, one-dimensional models, laser Doppler velocimetry, and numerical modeling. Local void fraction was measured using resistance probes and a newly developed approach to determining air/water threshold voltage for the probe. A tall column of eight inch diameter was constructed of Plexiglas and the distributor plate was manufactured to distribute air evenly through the base of the column. Data were gathered throughout the volume at three different gas throughputs. Bubble velocities proved difficult to measure using twin probes with cross-correlation because of radial bubble movement. A series of three-dimensional mean and RMS bubble and liquid velocity measurements were also obtained for a turbulent flow in a laboratory model of a bubble column. These measurements have been made using a three-component laser Doppler velocimeter (LDV), to determine velocity distributions non-intrusively. Finally, the gas-liquid flow inside a vertically situated circular isothermal column reactor was simulated numerically. 74 refs., 170 figs., 5 tabs.
Modelling failures in existing reinforced concrete columns
Kenneth J. Elwood
Experimental research and post-earthquake reconnaissance have demonstrated that reinforced concrete col- umns with light or widely spaced transverse reinforcement are vulnerable to shear failure, and in turn, axial failure dur- ing earthquakes. Based on experimental data, failure surfaces have been used to define the onset of shear and axial failure for such columns. After the response of the column intersects
LRCLaboratoryColumns New York -USA
Lebendiker, Mario
. Air in the column 3. Abnormal pressure increase during operation Possible cause 1. Dead volume at the column inlet. 2. Inlet frit partially clogged. 3. Outlet frit partially clogged. 4. Separation efficiency during the conditioning phase (see Section 2 for elimination of dead volume). PPrrootteecctt
Structural response of pyramidal core sandwich columns
Francois Cote; Russell Biagi; Hilary Bart-Smith; Vikram S. Deshpande
An experimental and analytical investigation is carried out to examine the in-plane compressive response of pyramidal truss core sandwich columns. The identified failure mechanisms include Euler buckling, shear buckling and face wrinkling. The operative mechanism is dependent on the properties of the bulk material and geometry of the sandwich columns and analytical formulae are derived for each of these modes.
Results from the Winogradsky Column Study
NSDL National Science Digital Library
Semester in Environmental Science
This web page features research results from a student project involving Winogradsky Columns constructed using sandy sediment and water collected from an estuary in Massachusetts. The page includes high-resolution images of the columns and profiles of hydrogen sulfide and methane versus depth.
Modeling of column apparatuses: A review
Doichinova, M., E-mail: firstname.lastname@example.com, E-mail: email@example.com; Popova-Krumova, P., E-mail: email@example.com, E-mail: firstname.lastname@example.com [Institute of Chemical Engineering, Bulgarian Academy of Sciences, Acad. St.Angelov str., Bl. 103, 1113 Sofia (Bulgaria)
This paper presents a review of the modeling method on the base of the physical approximations of the mechanics of continua, which have been developed for processes in column apparatuses. This method includes diffusion type of model for modeling of mass transfer with chemical reaction in column apparatuses with and without circulation zones. The diffusion type of model is used for modeling of scale effect in column apparatuses too. The study concluded that the proposal method is possibility for investigation the influence of radial non uniformity of the velocity distribution on the process efficiency, influence of zones breadths on the mass transfer efficiency in the column. The method of the column apparatuses modeling can be used for modeling of physical and chemical absorption, chemical adsorption, homogeneous and heterogeneous (catalytic) chemical reactions, airlift reactors for chemical and photochemical reactions.
Composite Column Design/Test Lab
NSDL National Science Digital Library
Johnson, Craig
Effective engineered composite design activities require predictive and quantitative methodology. This research incorporates engineering design, using smart spreadsheets, into a laboratory activity focusing on columns made of composite materials. In a previous work, a laboratory activity was developed supporting composite design of polymer matrix composite beams. The present work applies a similar approach expanded to ceramic composites in the form of columns. In the lab, students simulate composite columns and use a smart spreadsheet to help optimize their design for engineering performance, including specific properties. Parameters are discussed and evaluated before the column is made. The composite is then fabricated. Finally, the composite is tested and the experimental data (critical load for columns) is compared to predictions.
A study of a solvent extraction desalination processĀ
McFerrin, Arthur Ransom
, low extraction column efficiencies were obtained with the amine phase dispersed and much higher effi. cienci. es were obtained with the water phase dispersed in the Scheibel Column. In an attempt to partially explain the result. s, an effort... Flow Diagram of Hydrocyclone System. Effect of Amine Solubility in Water on Ratio of Na 53 and Cl Selectivities. 54 Selectivity of NaC1 in Amines. Selectivity of. NaC1 in Diisopropylamine. Selectivity of KCI in Diisopropylamine Extraction...
Tapered pulse tube for pulse tube refrigerators
Swift, Gregory W. (Sante Fe, NM); Olson, Jeffrey R. (San Mateo, CA)
Thermal insulation of the pulse tube in a pulse-tube refrigerator is maintained by optimally varying the radius of the pulse tube to suppress convective heat loss from mass flux streaming in the pulse tube. A simple cone with an optimum taper angle will often provide sufficient improvement. Alternatively, the pulse tube radius r as a function of axial position x can be shaped with r(x) such that streaming is optimally suppressed at each x.
Generation of short and intense attosecond pulses
NASA Astrophysics Data System (ADS)
Khan, Sabih Ud Din
Extremely broad bandwidth attosecond pulses (which can support 16as pulses) have been demonstrated in our lab based on spectral measurements, however, compensation of intrinsic chirp and their characterization has been a major bottleneck. In this work, we developed an attosecond streak camera using a multi-layer Mo/Si mirror (bandwidth can support ś100as pulses) and position sensitive time-of-flight detector, and the shortest measured pulse was 107.5as using DOG, which is close to the mirror bandwidth. We also developed a PCGPA based FROG-CRAB algorithm to characterize such short pulses, however, it uses the central momentum approximation and cannot be used for ultra-broad bandwidth pulses. To facilitate the characterization of such pulses, we developed PROOF using Fourier filtering and an evolutionary algorithm. We have demonstrated the characterization of pulses with a bandwidth corresponding to ś20as using synthetic data. We also for the first time demonstrated single attosecond pulses (SAP) generated using GDOG with a narrow gate width from a multi-cycle driving laser without CE-phase lock, which opens the possibility of scaling attosecond photon flux by extending the technique to peta-watt class lasers. Further, we generated intense attosecond pulse trains (APT) from laser ablated carbon plasmas and demonstrated ś9.5 times more intense pulses as compared to those from argon gas and for the first time demonstrated a broad continuum from a carbon plasma using DOG. Additionally, we demonstrated ś100 times enhancement in APT from gases by switching to 400 nm (blue) driving pulses instead of 800 nm (red) pulses. We measured the ellipticity dependence of high harmonics from blue pulses in argon, neon and helium, and developed a simple theoretical model to numerically calculate the ellipticity dependence with good agreement with experiments. Based on the ellipticity dependence, we proposed a new scheme of blue GDOG which we predict can be employed to extract intense SAP from an APT driven by blue laser pulses. We also demonstrated compression of long blue pulses into >240 microJ broad-bandwidth pulses using neon filled hollow core fiber, which is the highest reported pulse energy of short blue pulses. However, compression of phase using chirp mirrors is still a technical challenge.
Hollow-Cone Accretion Columns and Light-bending Effects
NASA Astrophysics Data System (ADS)
Leahy, D. A.
A set of new model calculations for pulse shapes from hollow cone-shaped accretion columns is carried out. The cones have a circular base on the neutron star centered on the magnetic poles and extend upward. Both straight cones and those that follow dipole field lines are considered. The difference is important only for tall cones. The emissivity dependence on the local angle normal to the emitting surface or to the magnetic field can be specified: here analytic formulae and tables to represent the Meszaros & Nagel emissivities were considered. The effects of gravitational light bending are included and have a major impact on the resulting beam patterns, as shown by comparison with patterns computed without light bending.
Test of LASL Ion Source with 200kV Pierce Accrelerating Column
C. R. Emigh; E. A. Meyer; D. W. Mueller
A 200-kV test stand has been constructed for design evaluation of an ion source and accelerating column to operate at 750 kV. Requirements are a 6% to 12% duty factor for a 30-mA. pton pulse current with a normalized emittance (Area ??┐\\/┐) of < 0.04 cm-mrad. The ion source is a Von Ardenne duoplasmatron with a large expansion cup. Beam
Trace metal analysis: selective sample (copper II) enrichment on an AlgaSORB column
Rachana Singh; B. B Prasad
A new approach to sample enrichment for copper(II) determination at trace level is reported. The silica-immobilised cationic polyelectrolyte, [poly (N-xylene-N,N? dicyclohexyl ethylenediamine dibromide)], capable of electrostatic binding with the biofilm of a natural alga Spirogyras sp is used in column separation for enrichment of trace analyte for accurate detection by differential pulse anodic stripping voltammetry. Algae¢silica preparation termed as AlgaSORB-sp
How to Calculate Molecular Column Density
NASA Astrophysics Data System (ADS)
Mangum, Jeffrey G.; Shirley, Yancy L.
The calculation of the molecular column density from molecular spectral (rotational or ro-vibrational) transition measurements is one of the most basic quantities derived from molecular spectroscopy. Starting from first principles where we describe the basic physics behind the radiative and collisional excitation of molecules and the radiative transfer of their emission, we derive a general expression for the molecular column density. As the calculation of the molecular column density involves a knowledge of the molecular energy level degeneracies, rotational partition functions, dipole moment matrix elements, and line strengths, we include generalized derivations of these molecule-specific quantities. Given that approximations to the column density equation are often useful, we explore the optically thin, optically thick, and low-frequency limits to our derived general molecular column density relation. We also evaluate the limitations of the common assumption that the molecular excitation temperature is constant and address the distinction between beam-averaged and source-averaged column densities. As non-LTE approaches to the calculation of molecular spectral line column density have become quite common, we summarize non-LTE models that calculate molecular cloud volume densities, kinetic temperatures, and molecular column densities. We conclude our discussion of the molecular column density with worked examples for C18O, C17O, N2H+, NH3, and H2CO. Ancillary information on some subtleties involving line profile functions, conversion between integrated flux and brightness temperature, the calculation of the uncertainty associated with an integrated intensity measurement, the calculation of spectral line optical depth using hyperfine or isotopologue measurements, the calculation of the kinetic temperature from a symmetric molecule excitation temperature measurement, and relative hyperfine intensity calculations for NH3 are presented in appendices. The intent of this document is to provide a reference for researchers studying astrophysical molecular spectroscopic measurements.
Rapid determination of Papaver somniferum alkaloids in process streams using monolithic column high-performance liquid chromatography with chemiluminescence detection
Jason W. Costin; Simon W. Lewis; Stuart D. Purcell; Lucy R. Waddell; Paul S. Francis; Neil W. Barnett
We have combined high-performance liquid chromatography (HPLC) separations using a monolithic column with acidic potassium permanganate and tris(2,2?-bipyridyl)ruthenium(II) chemiluminescence detection in a rapid and highly sensitive method to monitor the process of extracting opiate alkaloids from Papaver somniferum. Due to the high flow rates allowed with the monolithic column and the inherent selectivity of the chemiluminescence reactions, the four predominant
Flutter of cantilevered column under rocket thrust
NASA Astrophysics Data System (ADS)
Sugiyama, Yoshihiko; Katayama, Kazuo; Kinoi, Sigeru
This paper describes an experimental investigation on the flutter of visco-elastic cantilevers subjected to a tangential follower force. The force was produced by the direct installation of a real solid rocket motor to the tip end of the cantilevered columns. The columns lost their stability by flutter. The results were compared with theoretical flutter predictions made by accounting for an internal damping of the test columns, as well as the mass and size of the installed rocket motor. The introduction of the concept of instability in a finite time interval is of vital importance in predicting the experimental flutter force.
Investigating Bacteria with the Winogradsky Column
NSDL National Science Digital Library
Rogan, Brian
This is an instructor's guide to teaching about biodiversity in the microbial world. This activity encourages students to investigate bacteria using a Winogradsky Column. Students can create a unique environment with slight variations on the recipe; and soon have an inquiry project that could easily occupy the entire year. With the simple extensions given, teachers can isolate and grow a number of the species found in the column and extend this column to a number of examples in the real world showing the relevance of this complex yet deceptively simple lab.
Compaction force in a confined granular column.
Arroyo-Cetto, D; Pulos, G; Zenit, R; Jimķnez-Zapata, M A; Wassgren, C R
Experiments to determine the force required to push a granular column confined within a cylinder were performed. The experimental apparatus was mounted on a material testing system machine in order to obtain force and displacement measurements simultaneously. Experiments were performed for two different sphere diameters, two different cylinder diameters and for a range of piston displacement velocities. The force necessary to displace the column increases rapidly with the column height, in accordance with Janssen's theory. More importantly, we found that this force also increases with the displacement velocity. This unexpected behavior is an indication of the transition to rate-dependent behavior in dense granular flows. PMID:14682792
PSR beam-pulse formation and control
Hardekopf, R.A.
The Proton Storage Ring (PSR) is a major addition to the Weapons Neutron Research Facility (WNR) at LAMPF. It will act as a bunch compressor for the relatively long linac macropulses from LAMPF, tailoring them into short, intense pulses ideally suited for neutron-scattering research. This paper concentrates on the methods used to form these pulses before injection into the linac, to multiplex the PSR beam with other LAMPF users, and to synchronize the storage ring with pulse arrival time at injection and with the WNR mechanical neutron chopper at extraction.
Monolithic and core-shell columns in comprehensive two-dimensional HPLC: a review.
Jandera, Pavel; Hßjek, TomßÜ; Sta?kovß, Magda
The crucial point affecting the separation time in comprehensive two-dimensional liquid chromatography is the performance of the column used in the second dimension, which should allow highly efficient fast chromatographic separations in the short time available for the analysis of fractions transferred from the first to the second dimension (often 1Āmin or less). This can be accomplished on short columns packed with sub-2-?m particles, at the cost of very high operation pressure. Core-shell or silica monolithic columns have better permeability, and their use in the second dimension of comprehensive two-dimensional liquid chromatography with conventional liquid chromatography instrumentation is continuously increasing. Monolithic columns based on organic polymer matrices offer a wide selection of stationary phase chemistries, including new hydrophilic interaction liquid chromatography materials, which can be used in the design of novel two-dimensional separations. Some organic polymer monolithic materials offer a dual retention mechanism (reversed-phase hydrophilic interaction liquid chromatography), so a single column can be used in alternating runs for highly orthogonal off-line two-dimensional and even three-dimensional separations. In the present work, the properties of core-shell and silica gel monolithic columns are briefly summarized and their applications in two-dimensional separations of peptides, proteins, oligomer surfactants, fats and oils, carotenoids, phenolic and flavone compounds in plant extracts, food, and beverages are reviewed. PMID:25326881
Pulse-burst laser systems for fast Thomson scattering (invited)
Den Hartog, D. J. [Department of Physics, University of Wisconsin-Madison, 1150 University Avenue, Madison, Wisconsin 53706 (United States); Center for Magnetic Self-Organization in Laboratory and Astrophysical Plasmas, University of Wisconsin-Madison, Madison, Wisconsin 53706 (United States); Ambuel, J. R.; Holly, D. J.; Robl, P. E. [Physical Sciences Laboratory, University of Wisconsin-Madison, 3725 Schneider Drive, Stoughton, Wisconsin 53589 (United States); Borchardt, M. T.; Falkowski, A. F.; Harris, W. S.; Parke, E.; Reusch, J. A.; Stephens, H. D.; Yang, Y. M. [Department of Physics, University of Wisconsin-Madison, 1150 University Avenue, Madison, Wisconsin 53706 (United States)
Two standard commercial flashlamp-pumped Nd:YAG (YAG denotes yttrium aluminum garnet) lasers have been upgraded to ''pulse-burst'' capability. Each laser produces a burst of up to 15 2 J Q-switched pulses (1064 nm) at repetition rates of 1-12.5 kHz. Variable pulse-width drive (0.15-0.39 ms) of the flashlamps is accomplished by insulated gate bipolar transistor (IGBT) switching of electrolytic capacitor banks. Direct control of the laser Pockels cell drive enables optimal pulse energy extraction, and up to four 2 J laser pulses during one flashlamp pulse. These lasers are used in the Thomson scattering plasma diagnostic system on the MST reversed-field pinch to record the dynamic evolution of the electron temperature profile and temperature fluctuations. To further these investigations, a custom pulse-burst laser system with a maximum pulse repetition rate of 250 kHz is now being commissioned.
Pulse-burst laser systems for fast Thomson scattering (invited).
Den Hartog, D J; Ambuel, J R; Borchardt, M T; Falkowski, A F; Harris, W S; Holly, D J; Parke, E; Reusch, J A; Robl, P E; Stephens, H D; Yang, Y M
Two standard commercial flashlamp-pumped Nd:YAG (YAG denotes yttrium aluminum garnet) lasers have been upgraded to "pulse-burst" capability. Each laser produces a burst of up to 15 2 J Q-switched pulses (1064 nm) at repetition rates of 1-12.5 kHz. Variable pulse-width drive (0.15-0.39 ms) of the flashlamps is accomplished by insulated gate bipolar transistor (IGBT) switching of electrolytic capacitor banks. Direct control of the laser Pockels cell drive enables optimal pulse energy extraction, and up to four 2 J laser pulses during one flashlamp pulse. These lasers are used in the Thomson scattering plasma diagnostic system on the MST reversed-field pinch to record the dynamic evolution of the electron temperature profile and temperature fluctuations. To further these investigations, a custom pulse-burst laser system with a maximum pulse repetition rate of 250 kHz is now being commissioned. PMID:21033868
PRTR ion exchange vault column sampling
Cornwell, B.C.
This report documents ion exchange column sampling and Non Destructive Assay (NDA) results from activities in 1994, for the Plutonium Recycle Test Reactor (PRTR) ion exchange vault. The objective was to obtain sufficient information to prepare disposal documentation for the ion exchange columns found in the PRTR Ion exchange vault. This activity also allowed for the monitoring of the liquid level in the lower vault. The sampling activity contained five separate activities: (1) Sampling an ion exchange column and analyzing the ion exchange media for purpose of waste disposal; (2) Gamma and neutron NDA testing on ion exchange columns located in the upper vault; (3) Lower vault liquid level measurement; (4) Radiological survey of the upper vault; and (5) Secure the vault pending waste disposal.
Tests on duralumin columns for aircraft construction
NASA Technical Reports Server (NTRS)
Lee, John G
The following paper is based on the results of tests, upon duralumin columns, contained in two theses presented to the Department of Civil and Sanitary Engineering of the Massachusetts Institute of Technology.
Axisymmetric Column Collapse in a Rotating System
NASA Astrophysics Data System (ADS)
Warnett, Jay; Thomas, Peter; Dennisenko, Petr
We discuss experimental and computational results of a study investigating the collapse of an initially axisymmetric cylindrical column of granular material within a rotating environment of air or liquids. In industry this type of granular column collapse that is subject to background rotation is encountered, for instance, in the context of the spreading of powders and fertilizers. In comparison to its non-rotating counterpart the physical characteristics of the column collapse in a rotating system are expected to be modified by effects arising from centrifugal forces and Coriolis forces. We compare our new results for the rotating flow to data available in the literature for the collapse of granular columns in non-rotating systems to highlight the differences observed.
Reconstruction of the Column Shaft* Jari Pakkanen
Sheldon, Nathan D.
Reconstruction of the Column Shaft* Jari Pakkanen This document is author's final English version shafts is soft brown sandstone: since it is very easy to carve, it is an economical and quick building
Fault tolerant pulse synchronizationĀ
Deconda, Keerthi
Pulse synchronization is the evolution of spontaneous firing action across a network of sensor nodes. In the pulse synchronization model all nodes across a network produce a pulse, or "fire", at regular intervals even without access to a shared...
Commander prepares glass columns for electrophoresis experiment
NASA Technical Reports Server (NTRS)
Commander Jack Lousma prepares on of the glass columns for the electrophoresis test in the middeck area of the Columbia. The experiment, deployed in an L-shaped mode in upper right corner, consists of the processing unit with glass columns in which the separation takes place; a camera (partially obscurred by Lousma's face) to document the process; and a cryogenic freezer to freeze and store the samples after separation.
Gas Chromatograph Method Optimization Trade Study for RESOLVE: 20-meter Column v. 8-meter Column
NASA Technical Reports Server (NTRS)
Huz, Kateryna
RESOLVE is the payload on a Class D mission, Resource Prospector, which will prospect for water and other volatile resources at a lunar pole. The RESOLVE payload's primary scientific purpose includes determining the presence of water on the moon in the lunar regolith. In order to detect the water, a gas chromatograph (GC) will be used in conjunction with a mass spectrometer (MS). The goal of the experiment was to compare two GC column lengths and recommend which would be best for RESOLVE's purposes. Throughout the experiment, an Inficon Fusion GC and an Inficon Micro GC 3000 were used. The Fusion had a 20m long column with 0.25mm internal diameter (Id). The Micro GC 3000 had an 8m long column with a 0.32mm Id. By varying the column temperature and column pressure while holding all other parameters constant, the ideal conditions for testing with each column length in their individual instrument configurations were determined. The criteria used for determining the optimal method parameters included (in no particular order) (1) quickest run time, (2) peak sharpness, and (3) peak separation. After testing numerous combinations of temperature and pressure, the parameters for each column length that resulted in the most optimal data given my three criteria were selected. The ideal temperature and pressure for the 20m column were 95 C and 50psig. At this temperature and pressure, the peaks were separated and the retention times were shorter compared to other combinations. The Inficon Micro GC 3000 operated better at lower temperature mainly due to the shorter 8m column. The optimal column temperature and pressure were 70 C and 30psig. The Inficon Micro GC 3000 8m column had worse separation than the Inficon Fusion 20m column, but was able to separate water within a shorter run time. Therefore, the most significant tradeoff between the two column lengths was peak separation of the sample versus run time. After performing several tests, it was concluded that better detection via good peak separation with a longer run time is a better asset than moderate peak separation with a shorter run time. Even given that RESOLVE is highly interested in water and that mission timeline is of significant importance given the short seven-to-ten-day mission timeline, worse detection with an 8m column may lead to overlooking other substances existing on the moon that could advance planetary science. Thus, I recommend the 20m column. However, if mission timeline and water separation are deemed the highest priority, the 8m column should be selected due to its ability to separate water within a shorter run time than the 20m column.
Aromatics Extraction Plant Design Using Synthesis TechniquesĀ
Wilcox, R. J.; Nedwick, R.
the reboiler and condenser duties and temperatures and estimating the traffic and number of trays in each column to estimate its capital cost. APPUCATION TO THE SPECIFIC DESIGN A new plant was designed to produce benzene, toluene, and xylene by extraction... to extract an aromatics stream from a C 6 -C o heart cut of hydrogenated pyrolysis gasoline, leaving a raffinate containing paraffins and naphthenes. The Distillation Section distills the aromatics stream into high purity benzene, toluene, and Co...
Measurement of bromate in bread by high performance liquid chromatography with post-column flow reactor detection.
Himata, K; Noda, M; Ando, S; Yamada, Y
An analytical procedure was developed to measure bromate residues in baked goods using a sequence of clean-up procedures followed by high performance liquid chromatography (HPLC) with a post-column reaction for oxidants. Deionized water was used to extract bromate from bread samples. The extract was treated with a C-18 solid phase extraction column to remove lipids, a cation exchange column with the silver cation to remove chloride, and an ultrafiltration membrane to remove proteins. Further treatment of the extract with the sodium form of a propylsulphonic acid ion exchange column was necessary to remove the silver that leached from the silver column. The method had a detection limit of 3 ng/g in baked goods. Recoveries of bromate from breads ranged from 73 to 86% at a fortified bromate level of 5-100 ng/g. Pullman-type white bread, produced by a sponge and dough method, was prepared in our laboratory for measurement of residual bromate. The dough was scaled in three different weights at different specific volumes (3.8, 4.1, 4.3), and samples of each of the three weights were baked for six different baking times ranging from 24 to 34 min. When bromate at a level of 25 mg/kg was added to flour, no residual bromate was detected in any of the samples, regardless of weight and baking time. PMID:9519122
Comparison of surface and column measurements of aerosol scattering properties over the western North Atlantic Ocean at Bermuda
NASA Astrophysics Data System (ADS)
Aryal, R. P.; Voss, K. J.; Terman, P. A.; Keene, W. C.; Moody, J. L.; Welton, E. J.; Holben, B. N.
Light scattering and spectral absorption by size-resolved aerosols in near-surface air at Tudor Hill, Bermuda were measured continuously between January and June 2009. Vertical distributions of aerosol backscattering and column-averaged aerosol optical properties were characterized in parallel with a Micro-pulse lidar (MPL) and an automated sun-sky radiometer. Aerosol optical properties measured near the surface were often significantly correlated with those averaged over the column. These include scattering by near-surface bulk aerosol at 530 nm vs. column aerosol optical depth (AOD), near-surface sub-?m scattering fraction vs. column averaged sub-?m scattering fraction, the column averaged Angstrom exponent derived using a column integrated size distribution and complex refractive index. The relative contribution of submicron aerosol light scattering to total aerosol light scattering shows a slight enhancement of the column contribution of submicron particles over the surface measurements. Physical factors such as surface level wind speed have a more important affect on bulk aerosol light scattering at the surface.
Long pulse production from short pulses
Toeppen, John S. (Livermore, CA)
A method of producing a long output pulse (SA) from a short pump pulse (P), using an elongated amplified fiber (11) having a doped core (12) that provides an amplifying medium for light of one color when driven into an excited state by light of a shorter wavelength and a surrounding cladding 13. A seed beam (S) of the longer wavelength is injected into the core (12) at one end of the fiber (11) and a pump pulse (P) of the shorter wavelength is injected into the cladding (13) at the other end of the fiber (11). The counter-propagating seed beam (S) and pump pulse (P) will produce an amplified output pulse (SA) having a time duration equal to twice the transit time of the pump pulse (P) through the fiber (11) plus the length of the pump pulse (P).
Long pulse production from short pulses
Toeppen, J.S.
A method of producing a long output pulse from a short pump pulse is disclosed, using an elongated amplified fiber having a doped core that provides an amplifying medium for light of one color when driven into an excited state by light of a shorter wavelength and a surrounding cladding. A seed beam of the longer wavelength is injected into the core at one end of the fiber and a pump pulse of the shorter wavelength is injected into the cladding at the other end of the fiber. The counter-propagating seed beam and pump pulse will produce an amplified output pulse having a time duration equal to twice the transit time of the pump pulse through the fiber plus the length of the pump pulse. 3 figs.
Pulse Consumption, Satiety, and Weight Management1
McCrory, Megan A.; Hamaker, Bruce R.; Lovejoy, Jennifer C.; Eichelsdoerfer, Petra E.
The prevalence of obesity has reached epidemic proportions, making finding effective solutions to reduce obesity a public health priority. One part of the solution could be for individuals to increase consumption of nonoilseed pulses (dry beans, peas, chickpeas, and lentils), because they have nutritional attributes thought to benefit weight control, including slowly digestible carbohydrates, high fiber and protein contents, and moderate energy density. Observational studies consistently show an inverse relationship between pulse consumption and BMI or risk for obesity, but many do not control for potentially confounding dietary and other lifestyle factors. Short-term (?1 d) experimental studies using meals controlled for energy, but not those controlled for available carbohydrate, show that pulse consumption increases satiety over 2¢4 h, suggesting that at least part of the effect of pulses on satiety is mediated by available carbohydrate amount or composition. Randomized controlled trials generally support a beneficial effect of pulses on weight loss when pulse consumption is coupled with energy restriction, but not without energy restriction. However, few randomized trials have been conducted and most were short term (3¢8 wk for whole pulses and 4¢12 wk for pulse extracts). Overall, there is some indication of a beneficial effect of pulses on short-term satiety and weight loss during intentional energy restriction, but more studies are needed in this area, particularly those that are longer term (?1 y), investigate the optimal amount of pulses to consume for weight control, and include behavioral elements to help overcome barriers to pulse consumption. PMID:22043448
Mansour Amin; Effat Abasi Montazeri; Mohammad Ali Mashhadizadeh; Ahmad Farajzadeh Sheikh
Objective: The objective of this study was characterization of antimicrobial extract of shallot in terms of its stability at different pH, Heat, enzymes and detergents and also determination of its MIC and shelf life. Methodology: Active fraction was determined by column chromatography and agar diffusion test. The amount of carbohydrate and protein in different forms of shallot extract were estimated.
Extraction, Purification, and Spectroscopic Characterization of a Mixture of Capsaicinoids
ERIC Educational Resources Information Center
Wagner, Carl E.; Cahill, Thomas M.; Marshall, Pamela A.
This laboratory experiment provides a safe and effective way to instruct undergraduate organic chemistry students about natural-product extraction, purification, and NMR spectroscopic characterization. On the first day, students extract dried habanero peppers with toluene, perform a pipet silica gel column to separate carotenoids fromģ
Solidphase extraction of polycyclic aromatic hydrocarbons from soil samples
P. R. Kootstra; M. H. C. Straub; G. H. Stil; E. G. van der Velde; W. Hesselink; C. C. J. Land
A new solid-phase extraction (SPE) method was developed for the analysis of 16 polyaromatic hydrocarbons (PAHs) on the US Environmental Protection Agency priority list, in soil samples. Different types of SPE columns were tested and conditioning and elution steps were optimised. In the final procedure, soil samples are extracted with acetone and, after dilution with HPLC-grade water, loaded on a
Counterflow isotachophoresis in a monolithic column.
Liu, Bingwen; Cong, Yongzheng; Ivory, Cornelius F
This study describes stationary counterflow isotachophoresis (ITP) in a poly(acrylamide-co-N,N'-methylenebisacrylamide) monolithic column as a means for improving ITP processing capacity and reducing dispersion. The flow profile in the monolith was predicted using COMSOL's Brinkman Equation application mode, which revealed that the flow profile was mainly determined by monolith permeability. As monolith permeability decreases, the flow profile changes from a parabolic shape to a plug shape. An experimental monolithic column was prepared in a fused-silica capillary using an ultraviolet-initiated polymerization method. A monolithic column made from 8% (wt.) monomer was chosen for the stationary counterflow ITP experiments. Counterflow ITP in the monolithic column showed undistorted analyte zones with significantly reduced dispersion compared to the severe dispersion observed in an open capillary. Particularly, for r-phycoerythrin focused by counterflow ITP, its zone width in the monolithic column was only one-third that observed in an open capillary. These experiments demonstrate that stationary counterflow ITP in monoliths can be a robust and practical electrofocusing method. PMID:24935025
SF STATE STUDENT PULSE SURVEY Spring 2013 Academic Planning and Development Academic Institutional Research (air.sfsu.edu) March 2013 #12;SF State Student Pulse Survey, Spring 2013 Page 1 Table of Contents State Student Pulse Survey, Spring 2013 Page 2 SF STATE Ł Student Pulse Survey Executive Summary
The SNS Extraction Fast Kicker System is a very high power, high repetition rate pulsed power system. It was design and developed at Brookhaven National Laboratory. This system will consist of fourteen identical high voltage, high current modulators, and their auxiliary control and charging systems. The modulators will drive fourteen extraction magnet sections located inside of the SNS accumulator ring. The required kicker field rise time is 200 ns, a pulse flattop of 700 ns, a pulse repetition rate of 60 pulse-per-second. A 2500 Ampere per modulator output is required to reach the extraction kicker magnetic field strength. This design features a Blumlein Pulse-Forming-Network based topology, a low beam impedance termination, a fast current switching thyratron, and low inductance capacitor banks. It has a maximum charging voltage of 50kV, an open circuit output of 100kV, and a designed maximum pulsed current output of 4kA per modulator. The overall system output will be multiple GVA with 60 Pulse-per-second repetition rate. A prototype modulator has been successfully built and tested well above the SNS requirement. The modulator system production is in progress.
PCB fluxes from the sediment to the water column following resuspension A column experiment
Paris-Sud XI, Universitķ de
PCB fluxes from the sediment to the water column following resuspension Ł A column experiment was systematically due to significant levels of PCB-DL and PCDD/F in fish tissue. New campaigns of characterization of cubic meters of contaminated sediments and to improve the understanding of the behavior of PCB
Ionization instability in a turbulent plasma column
Crispin, Y. (Florida, University, Gainesville (United States))
The problem of the onset of ionization waves in a turbulent plasma column is studied using linear stability theory. A mathematical model of the mutual interactions between the gas flow turbulence, Joule heating, ionization and ambipolar diffusion in the cylindrical plasma column is developed. Axially homogeneous stationary solutions of the turbulent plasma column are presented. These solutions are then perturbed and their stability to longitudinal disturbances is investigated. The growth rate of the disturbances is calculated for argon at a pressure of 50 torr, a range of currents between 0.2 and 2 A and Reynolds number values of 0, 6000 and 10,000. It is found that the gas turbulence delays the onset of ionization waves for a wide range of discharge currents. 20 refs.
Scaling up of high-speed countercurrent chromatographic apparatus with three columns connected in series for rapid preparation of (-)-epicatechin.
Du, Qingbao; Jiang, Heyuan; Yin, Junfeng; Xu, Yongquan; Du, Wenkai; Li, Bo; Du, Qizhen
In the present study, compact high-speed countercurrent chromatographic apparatus was constructed with three columns connected in series. Two sets of columns were prepared from 10 mm and 12 mm I.D. tubing to form 12 L and 15 L capacities, respectively. Performance of these columns was compared for the separation of (-)-epicatechin gallate (ECG) from a tea extract by flash countercurrent chromatography (FCCC). In each separation, 200 g of the tea extract in 1600 mL of mobile phase was loaded onto the column. The 12 L column gave 7.5 L (35 g of ECG) and the 15 L column gave 9 L (40 g of ECG) of ECG solution without impurities. The ECG solution was directly hydrolyzed by tannase into (-)-epicatechin. The hydrolysate was purified by flash chromatography on AB-8 macroporous resin to give 52 g of EC (purity 99.1%). This scaled up apparatus could be used for the industrial separation of natural products. PMID:23219478
Stabilization of Regional Column Models by Parameterized Dynamical Tendencies
NASA Astrophysics Data System (ADS)
Bergman, J. W.
Atmospheric Single Column Models (SCMs) provide an efficient modeling framework for regional studies. In these models, vertical profiles of temperature and humidity evolve in response to diabatic interactions within the column and adiabatic tendencies produced by by the large scale circulation. The adiabatic tendencies are either prescribed or neglected and,thus, decoupled from the diabatic tendencies. This decoupling can lead to the rapid development of unrealistic atmospheric states. In particular, the temperature profiles from a SCM can become unrealistic enough within just a few hours to render any meaningful diagnosis difficult, if not impossible. We have implemented an SCM framework in which the adiabatic tendencies are coupled to the column physics through a formula that links vertical temperature advection to the time-history of diabatic heating rates. The parameters in any such coupling formula should depend in principle depend upon the zonal, meridional, vertical and temporal scales of the heating. In practice, however, we find that the dependence is weak over a wide range of zonal and meridional scales; the vertical dependence is accounted for in the formula itself, as is also the temporal dependence by considering the time history of the diabatic forcing rather than just instantaneous values. The effect of this dynamical coupling on the behavior of an SCM extracted from the NCAR CCM is investigated here. Because of the coupling, only the mean temperature and humidity profiles for the environment in which the column is embedded need to be explicitly specified; all other quantities are generated by the model. The coupled SCM is tested in tropical conditions during the TOGA COARE period. Control runs and 100-member ensembles, in which initial temperature and humidity profiles are perturbed, are run for environmental conditions taken from 85 sets of observed temperature and humidity profiles. The same data are also used to force the original, dynamically uncoupled, SCM. Coupling substantially reduces the bias and variability of the SCM. Temperature and humidity profiles for each of the 85 sets of runs are maintained within realistic values in the coupled SCM, whereas in the uncoupled SCM the bias often exceeds 10 K. However, the sensitivity to initial perturbations in the two models is similar. Perhaps the most important benefit of the coupling is that it allows us to diagnose error growth in the SCM while maintaining a realistic atmospheric state.
Mass transfer in a wetted wall column
Platt, Allison M
MASS TRANSPER IM A WETTED WALL COLDMM A Thesis Allison M. Platt June, 1950 MASS TRANSFER IN A WETTED WALL COLUMN A Thesis Allison M. Platt June~ 1950 Approved as to st@i and content recommended: Head of the Department of C cal Engineering... MASS TRANSFER IN A WETTED WALL COLUMN A Thesis Submitted to the Faculty of the Agricultural snd Mechanical College oi' Texas Partial FulfiUment of the Requirements for the Degree of Master of Science ~or Sub)ect: Chemical Engineering Allison M...
Multidimensional spectroscopy with a single broadband phase-shaped laser pulse Rachel Glenn and Shaul Mukamel
Mukamel, Shaul
are narrower than compared to a transform limited pulse.26 This technique27 can be used to extract the lineMultidimensional spectroscopy with a single broadband phase-shaped laser pulse Rachel Glenn-free molecular alignment control by phase-shaped femtosecond laser pulse J. Chem. Phys. 135, 224308 (2011); 10
Modulation instability in a highly nonlinear fiber for discrete-time pulsed random bit generation.
Wang, Xie; Li, Xiao-Zhou; Chan, Sze-Chun; Wong, Kenneth K Y
A simple yet high-speed scheme by utilizing modulation instability (MI) on the discrete-time generation of random bits is proposed and demonstrated experimentally. We develop MI pulses by pumping a highly nonlinear fiber in the anomalous dispersion regime using a mode-locked laser. MI pulses contain fluctuating pulse-to-pulse variations of peak intensities for extraction into random bits. At a repetition rate of 10ĀGHz, 5Ābits are extracted from each pulse in generating random bits at 50ĀGbps, as verified by the National Institute of Standards and Technology test suite. PMID:26030584
All-fiber based amplification of 40 ps pulses from a gain-switched laser diode.
Kanzelmeyer, Sebastian; Sayinc, Hakan; Theeg, Thomas; Frede, Maik; Neumann, Joerg; Kracht, Dietmar
Amplification of a gain-switched laser diode is demonstrated in an all-fiber based setup. The amplified spontaneous emission between two consecutive pulses was investigated quantitatively in the time domain. A maximum pulse energy of 13 ĄJ at a repetition rate of 1 MHz and a pulse duration of 40 ps was extracted, corresponding to a peak power of 270 KW. To the best of our knowledge, this is the highest extracted pulse energy from a laser system seeded by a gain-switched laser diode. Temporal pulse deformation due to intrapulse Raman scattering was observed in the reported system. PMID:21369000
Density and velocity of H{sup -} in the extraction region of a negative ion source estimated from the change in H{sup -} beam current due to a pulse laser injection
Matsumoto, Y.; Nishiura, M.; Matsuoka, K.; Wada, M.; Sasao, M.; Yamaoka, H. [National Institute for Fusion Science (NIFS), Toki, Gifu 509-5292 (Japan); Department of Electronics, Doshisha University, Kyotanabe, Kyoto 610-0321 (Japan); Tohoku University, Sendai 980-8579 (Japan); Harima Institute, RIKEN -Institute of Physical and Chemical Research, Hyogo 679-5148 (Japan)
A method to estimate H{sup -} density and velocity in the extraction region of a negative ion source plasma without a Langmuir probe is developed. It utilizes the laser photodetachment with a Faraday cup (PD-FC). The H{sup -} parameters estimated by PD-FC are compared to the results measured by laser-photodetachment with a Langmuir probe (PD-LP). The result shows that H{sup -} velocity estimated by PD-FC is in good agreement with the PD-LP result. Meanwhile, H{sup -} density estimated by PD-FC is twice larger than the PD-LP result. Though a more detailed research, including more effects that are ignored in this study, is needed for H{sup -} density measurement, PD-FC will be a very useful tool for H{sup -} measurements especially near an extraction hole in negative ion sources.
Drying and burning wood waste using pulse combustion
Buckkowski, A.G.; Eng, P.; Kitchen, J.A. [Novadyne Ltd., Ontario (Canada)
Development of an industrial dryer using pulse combustion as a heating source for drying wood waste has continued. Pulse combustion offers the advantage of high heat transfer, efficient combustion, low NOx emissions and a source of kinetic energy for providing a motive force for a drying system. In our experiments, the drying system consists of a pulse combustor and a vertical drying column. The wood waste is injected into the exhaust gases from the combustor where the turbulence created by the pulsations enhance the drying process by reducing the boundary layer thicknesses. The material is further dried in the vertical drying column, then separated from the conveying airstream using a cyclone. The paper discusses two aspects of the drying system. Firstly, the performance of the drying tests are reviewed. Tests with the 1,000,000 BTU/hr test rig have shown that a gas-fired pulse combustion dryer can dry materials such as sawdust and pulverized hog fuel from a moisture content of 50% down to a 30% in a single pass, or further with multiple passes, without scorching or burning. Preliminary figures show that the operating costs of the dryer are reduced due to the kinetic energy created by the pulse combustor which offsets the use of electricity. Secondly, it has been shown that a pulse combustor can be fired with wood waste and thereby providing the potential to displace natural gas or propane as a fuel. The development of the wood burning combustor is reviewed.
Ultrafast optical pulse shaping
NASA Astrophysics Data System (ADS)
Agostinelli, J. A.
A passive pulse shaping system and two active pulse shaping systems are constructed and tested experimentally. Each system is analyzed and the analytical and experimental results are compared. For the active systems, the ultimate risetimes are calculated for the particular active devices which are utilized. A fairly comprehensive review of the entire field of ultrafast pulse shaping is undertaken. The passive system incorporates a pair of diffraction gratings and various filtering operations. It produces pulses of arbitrary temporal intensity profile from short (mode locked Nd:YAG) input pulses. The shape resolution in the output pulse is of the order of the input pulsewidth. The shaped output pulse is shown to be linearly frequency modulated. With the largest gratings available commercially, total pulse lengths of about 2 ns appear to be possible. The active pulse shaping systems include linear electro-optic (Pockels cell) and nonlinear electro-optic (Kerr cell) modulators, each driven by light activated semiconductor switch circuitry.
A comparison study of in-column and on-column detection for electrochromatography.
Zhang, Qier; Xu, Lingjia; Zhou, Zhuoheng; Yang, Lijun; Wang, Qiuquan; Zhang, Bo
Duplex capillary columns, the standard for electrochromatography using optical detection, consist of a packed and an open section. Normally, optical detection is performed in an on-column manner, i.e. at a point right after the packed section. It was deemed that band broadening may take place when an analyte band travels from the packed bed, through the frit and down to the open section. In this study, without using any sintering steps for fritting or window creation, robust packed capillary columns were prepared using transparent capillaries based on single particle fritting technology. The detection point could be easily shifted by simply sliding the transparent column against the ultraviolet (UV) beam. In this way, the band broadening effect was directly evaluated as a function of the detection point, which was positioned before or after the end frit. The consistent van Deemter curves recorded indicate that there was no efficiency difference between the positions investigated. The result proved that the significant band broadening effect previously observed via on-column detection should be caused by the sintered frit used, while the single particle frit made through a purely physical process did not lead to efficiency degradation. The conservative separation performance recorded at different positions around the column's end also suggests the applicability of on-line tandem detection strategy, e.g. UV followed by mass spectrometry (MS), on the same capillary column, which should be a promising approach to mining multiplex detection information from a single microseparation process. PMID:25171946
Short-pulse operation with the SITEX negative ion source
NASA Astrophysics Data System (ADS)
Dagenhart, W. K.; Stirling, W. L.; Banic, G. M.; Barber, G. C.; Ponte, N. S.; Whealton, J. H.
The successful high current, long-pulse SITEX source experiments with H- beams have been extended to D- operation and to short-pulse H- and D- beam acceleration. Extracted D- beam current densities of 100 mA/cm2 at the plasma grid have been achieved for 3 s at a total beam of 260 mA and 10 keV. The extracted electron-to-D- ratio is <5% with ?100% of the extracted electrons collected at 2 keV. Short-pulse beams down to 10 ms in length have been accelerated with the minimum pulse length determined by the power supply time constants. Optics of the accelerated beam is ?(1/e)?=▒0.48░, which corresponds to a normalized emittance perpendicular to the slot of 0.0007? cm-mrad. These data place an upper limit on the surface conversion D- ion temperature of 0.7 eV.
Extendible column can be stowed on drum
NASA Technical Reports Server (NTRS)
Holtz, G. M.; Howard, E. A.
Column formed from a series of segments held together by an internal spring or cable can be coiled on a drum or extended into a rigid structure. This storable coil is useful in boring for soil samples and supporting electrical and optical sensors.
Thermal Analysis of LANL Ion Exchange Column
Laurinat, J.E.
This document reports results from an ion exchange column heat transfer analysis requested by Los Alamos National Laboratory (LANL). The object of the analysis is to demonstrate that the decay heat from the Pu-238 will not cause resin bed temperatures to increase to a level where the resin significantly degrades.
Relationship Advice Columns from Two Popular Magazines
Lori R. Kogan; Julie A. Kellaway
The relationship advice columns for two popular magazines (one targeted to female and the other to male readers) were discussed within the conceptual frameworks of centerfold syndrome and appearance obsession. Centerfold syndrome is a theory that describes the way men view women and sexuality. The female counterpart is appearance obsession which theorizes that women are motivated to meet unrealistic beauty
Nonmonotonic excitation rates in argon positive column
Arslanbekov, R.R.; Kolobov, V.I.; Bogdanov, E.A.; Kudryavtsev, A.A. [CFD Research Corporation, Huntsville, Alabama, 35805 (United States); St. Petersburg State University, 198504 (Russian Federation)
Nonmonotonic radial distributions of electron excitation rates are obtained in simulations of positive column (PC) in argon for a wide range of gas pressures 5
Hydrodynamics of Falling Mine in Water Column
Peter C. Chu; Anthony F. Gilles; Chenwu Fan; Peter Fleischer
The hydrodynamic features of a falling mine into the water column is investigated experimentally. The experiment consisted of dropping three cylindrical model mines of various lengths into a pool where the trajectories were filmed from two angles. The controlled parameters were, mine parameters (length to diameter ratio, center of mass location), and initial conditions (initial velocity, and drop angle). Results
The parallel complexity of minimizing column conflicts
John E. Savage; Markus G. Wloka
Two-layer channel routers typically require a post-processing phase to reduce or eliminate column conflicts. Attempts have been made to parallelize this problem using local search heuristics that swap horizontal channel wire segments. The authors show that all such heuristics for this problem are P-hard and unlikely to be efficiently parallelizable
Alfven surface waves along cylindrical plasma columns
C. Uberoi; K. Somasundaram
The analysis deals with the properties of Alfven waves along a cylindrical plasma column situated in a vacuum or in another plasma medium. In the case of vacuum, the phase velocity of the surface waves is shown to be greater than the bulk Alfven velocity. The symmetric modes propagate as forward waves, but the asymmetric modes change from backward to
Algorithmic Game Theory Column Mario Mavronicolas
Mavronicolas, Marios
Algorithmic Game Theory Column by Mario Mavronicolas Department of Computer Science, University in Algorithmic Game Theory today. The complexity of this problem has been found to be very sensitive with problems of equilibrium computation. 1 Introduction Noncooperative Game Theory has been providing
Desulfurization of coal by microbial column flotation
Ohmura, Naoya; Saiki, Hiroshi (Central Research Inst. of Electric Power Industry, Chiba (Japan). Dept. of Biotechnology)
Twenty-three strains capable of oxidizing iron were isolated from coal and ore storage sites as well as coal and ore mines, volcanic areas, and hot spring. Four strains were found to have high iron-oxidizing activity. One strain (T-4) was selected for this experiment since the strain showed the fastest leaching rate of iron and sulfate from pyrite among the four strains. The T-4 strain was assigned for Thiobacillus ferrooxidans from its cultural and morphological characteristics. Bacterial treatment was applied to column flotation. An increase of cell density in the microbial column flotation resulted in the increase of pyrite removal from a coal-pyrite mixture with corresponding decrease of coal recovery. The addition of kerosene into the microbial column flotation increased the recovery of the imitated coal from 55% (without kerosene) to 81% (with 50 [mu]L/L kerosene) with the reduction of pyrite sulfur content from11% (feed coal) to 3.9% (product coal). An excellent separation was obtained by the microbial flotation using a long column which had a length-diameter (L/D) ratio of 12.7.
"Dry-column" chromatography of plant pigments
NASA Technical Reports Server (NTRS)
Woeller, F. H.; Lehwalt, M. F.; Oyama, V. I.
Separation of plant pigments which can be accomplished on thin-layer silica plates with mixture of petroleum ether, halocarbon, acetone, and polar solvent can be readily translated into dry-column technique that yields reproducible chromatograms after elution in fashion of liquid chromatography with fluorimeter as detector. Best solvent system was found to be mixture of petroleum ether, dichloromethane, acetone, and ethyl acetate.
ACM SIGACT news distributed computing column 13
Sergio Rajsbaum
The Distributed Computing Column covers the theory of systems that are composed of a number of interacting computing elements. These include problems of communication and networking, databases, distributed shared memory, multiprocessor architectures, operating systems, verification, Internet, and the Web.This issue describes the PODC 20th anniversary Special Issue published by Distributed Computing journal.
Moses, E.I.
A laser pulse stacking method is disclosed. A problem with the prior art has been the generation of a series of laser beam pulses where the outer and inner regions of the beams are generated so as to form radially non-synchronous pulses. Such pulses thus have a non-uniform cross-sectional area with respect to the outer and inner edges of the pulses. The present invention provides a solution by combining the temporally non-uniform pulses in a stacking effect to thus provide a more uniform temporal synchronism over the beam diameter. 2 figs.
Study of hydrodynamic behaviour in bubble columns and external loop airlift reactors through analysis of pressure fluctuations
C. Vial; E. Camarasa; S. Poncin; G. Wild; N. Midoux; J. Bouillard
Recent methods of regime identification based on pressure fluctuations analysis have been applied both in a bubble column and an external loop airlift reactor with several spargers. Their ability to determine regime transition and to extract regime features is compared. A new method based on the auto-correlation function is proposed. This method is shown to be simple and efficient. It
Determination of tetracyclines in food samples by molecularly imprinted monolithic column coupling with high performance liquid chromatography
Xiangli Sun; Xiwen He; Yukui Zhang; Langxing Chen
A novel solid phase extraction (SPE) method for determination of tetracyclines (TCs) in milk and honey samples by molecularly imprinted monolithic column was developed. Using tetracycline (TC) as the template, methacrylic acid (MAA) as the functional monomer, ethylene glycol dimethacrylate (EGDMA) as the cross-linker, methanol as the solvent, cyclohexanol and dodecanol as the mixed porogenic solvents, a TC imprinted monolithic
Fractionation and cleanup of sample extracts prior to instrumental analysis is usually accomplished by column chromatography, gel permeation chromatography, or acid-base partitioning. n this report, the results of a study are described in which we investigated the application of ...
Analysis of microwave leaky modes propagating through laser plasma filaments column waveguide
NASA Astrophysics Data System (ADS)
Alshershby, Mostafa; Hao, Zuoqiang; Lin, Jingquan
A plasma column waveguide formed by a bundle of closely spaced plasma filaments induced by the propagation of ultrafast laser pulses in air and revived by a longer infrared laser pulse is shown to support microwave radiation. We consider values of both the plasma electron density and microwave frequency for which the refractive index of plasma is lower than the refractive index of air; therefore, a leaky plasma waveguide can be realized in extremely high frequency band. The guiding mechanism does not require high conductance of the plasma and can be easily excited by using commercial femtosecond laser sources. A theoretical study of leaky mode characteristics of isotropic and homogeneous plasma column waveguides is investigated with several values of plasma and waveguide structure parameters. The microwave transmission loss was found to be mainly caused by the microwave leakage through the air-plasma interface and is weakly dependent on the plasma absorption. In spite of losses of microwaves caused by leakage and plasma absorption, it is shown to be much lower than both that accompanying to surface waves attaching to single conducting plasma wire and the free space propagation over distances in the order of the filament length, which opens exciting perspectives for short distance point to point wireless transmission of pulsed-modulated microwaves.
Analysis of microwave leaky modes propagating through laser plasma filaments column waveguide
Alshershby, Mostafa; Hao Zuoqiang; Lin Jingquan [School of Science, Changchun University of Science and Technology, Changchun 130022 (China)
A plasma column waveguide formed by a bundle of closely spaced plasma filaments induced by the propagation of ultrafast laser pulses in air and revived by a longer infrared laser pulse is shown to support microwave radiation. We consider values of both the plasma electron density and microwave frequency for which the refractive index of plasma is lower than the refractive index of air; therefore, a leaky plasma waveguide can be realized in extremely high frequency band. The guiding mechanism does not require high conductance of the plasma and can be easily excited by using commercial femtosecond laser sources. A theoretical study of leaky mode characteristics of isotropic and homogeneous plasma column waveguides is investigated with several values of plasma and waveguide structure parameters. The microwave transmission loss was found to be mainly caused by the microwave leakage through the air-plasma interface and is weakly dependent on the plasma absorption. In spite of losses of microwaves caused by leakage and plasma absorption, it is shown to be much lower than both that accompanying to surface waves attaching to single conducting plasma wire and the free space propagation over distances in the order of the filament length, which opens exciting perspectives for short distance point to point wireless transmission of pulsed-modulated microwaves.
A network model for blind source extraction in various ill-conditioned cases
Yuanqing Li; Jun Wang
This paper discusses blind source extraction in various ill-conditioned cases based on a simple extraction network model. Extractability is first analyzed for the following ill-conditioned cases: the mixing matrix is square but singular, the number of sensors is smaller than that of sources, the number of sensors is larger than that of sources but the column rank of mixing matrix
Determination of pesticides in soil samples by solid phase extraction disks
M. J. Redondo; M. J. Ruiz; R. Boluda
A systematic study comparing the methodology and analytical results obtained in an investigation of seven pesticide residues (Molinate, Atrazine, Carbofuran, Pirimicarb, Prometryn, Malathion and Tetrachlorvinphos) in soil samples is reported. Solid-phase extraction (SPE) using glass columns and 47 mm disks of octyl and octadecyl-bonded silica was used in the pesticide analysis. The best extraction efficiency and clearest extracts are obtained
Bi-column method for purification of transcription factors.
Gadgil, H; Taylor, W L; Jarrett, H W
A novel bi-column method for purifying transcription factors, using two different columns and two different elution strategies is described. Lac repressor elutes at lower heparin concentrations from a lower affinity lactose operatorl (Op1)-Sepharose column than from a higher affinity column containing the same sequence with a T18:A18 tail (Op1T18). A bi-column method was developed in which lac repressor fusion protein is eluted from the Op1-Sepharose with a low heparin concentration and trapped on a Op1T18-Sepharose column because of its higher affinity for the lac repressor protein. Elution of the latter column with buffer containing a high salt concentration gives significantly purer transcription factor than the conventionally used single column methods and removes residual heparin. Highly pure CAAT enhancer binding protein and the B3 transcription factor are also obtained by using variants of this bi-column method. PMID:11206779
... 3 to 4 hours after the procedure The extraction site becomes very painful -- This may be a sign that you have developed a dry socket. If you have an infection, your dentist usually will prescribe antibiotics.
Wai, Chien M. (Moscow, ID); Laintz, Kenneth E. (Los Alamos, NM)
A method of extracting metalloid and metal species from a solid or liquid material by exposing the material to a supercritical fluid solvent containing a chelating agent is described. The chelating agent forms chelates that are soluble in the supercritical fluid to allow removal of the species from the material. In preferred embodiments, the extraction solvent is supercritical carbon dioxide and the chelating agent is a fluorinated .beta.-diketone. In especially preferred embodiments the extraction solvent is supercritical carbon dioxide, and the chelating agent comprises a fluorinated .beta.-diketone and a trialkyl phosphate, or a fluorinated .beta.-diketone and a trialkylphosphine oxide. Although a trialkyl phosphate can extract lanthanides and actinides from acidic solutions, a binary mixture comprising a fluorinated .beta.-diketone and a trialkyl phosphate or a trialkylphosphine oxide tends to enhance the extraction efficiencies for actinides and lanthanides. The method provides an environmentally benign process for removing contaminants from industrial waste without using acids or biologically harmful solvents. The method is particularly useful for extracting actinides and lanthanides from acidic solutions. The chelate and supercritical fluid can be regenerated, and the contaminant species recovered, to provide an economic, efficient process.
Erkal, Denis [Department of Physics, University of Chicago, Chicago, IL 60637 (United States); Gnedin, Nickolay Y. [Particle Astrophysics Center, Fermi National Accelerator Laboratory, Batavia, IL 60510 (United States); Kravtsov, Andrey V. [Kavli Institute for Cosmological Physics and Enrico Fermi Institute, University of Chicago, Chicago, IL 60637 (United States)
We study the high column density regime of the H I column density distribution function and argue that there are two distinct features: a turnover at N{sub H{sub I}} Almost-Equal-To 10{sup 21} cm{sup -2}, which is present at both z = 0 and z Almost-Equal-To 3, and a lack of systems above N{sub H{sub I}} Almost-Equal-To 10{sup 22} cm{sup -2} at z = 0. Using observations of the column density distribution, we argue that the H I-H{sub 2} transition does not cause the turnover at N{sub H{sub I}} Almost-Equal-To 10{sup 21} cm{sup -2} but can plausibly explain the turnover at N{sub H{sub I}} {approx}> 10{sup 22} cm{sup -2}. We compute the H I column density distribution of individual galaxies in the THINGS sample and show that the turnover column density depends only weakly on metallicity. Furthermore, we show that the column density distribution of galaxies, corrected for inclination, is insensitive to the resolution of the H I map or to averaging in radial shells. Our results indicate that the similarity of H I column density distributions at z = 3 and 0 is due to the similarity of the maximum H I surface densities of high-z and low-z disks, set presumably by universal processes that shape properties of the gaseous disks of galaxies. Using fully cosmological simulations, we explore other candidate physical mechanisms that could produce a turnover in the column density distribution. We show that while turbulence within giant molecular clouds cannot affect the damped Ly{alpha} column density distribution, stellar feedback can affect it significantly if the feedback is sufficiently effective in removing gas from the central 2-3 kpc of high-redshift galaxies. Finally, we argue that it is meaningful to compare column densities averaged over {approx} kpc scales with those estimated from quasar spectra that probe sub-pc scales due to the steep power spectrum of H I column density fluctuations observed in nearby galaxies.
Supercritical Fluid Chromatography of polyphenolic compounds in grape seed extract
A. Karnangerpour; M. Ashraf-Khorassani; L. T. Taylor; H. M. McNair; L. Chorida
SummaryĀĀSupercritical Fluid Chromatography with a packed column on a mixture of eight polyphenols has been optimized. Carbon dioxide\\u000a which was modified with methanol which contained less than 1% (w\\/w) citric acid as a secondary additive served as the mobile\\u000a phase. Two tandem diol columns were used sequentially. The optimized method was applied to a supercritical fluid grape seed\\u000a extract. Various
Determination of losartan, telmisartan, and valsartan by direct injection of human urine into a column-switching liquid chromatographic system with fluorescence detection
MarĒa del Rosario Brunetto; Yaritza Contreras; Sabrina Clavijo; Dina Torres; Yelitza Delgado; Fernando Ovalles; Carlos Ayala; Mßximo Gallignani; Josķ Manuel Estela; VĒctor CerdÓ Martin
Column-switching high-performance liquid chromatographic (HPLC) method has been developed and validated for quantification of losartan, telmisartan, and valsartan in human urine. Urine samples were diluted on the extraction mobile phase (1:4, v\\/v) and a volume of 20?L of this mixture were directly injected onto the HPLC system. The analytes were extracted from the matrix using an on-line solid-phase extraction procedure
Lamb, Erin S.; Wright, Logan G.; Wise, Frank W.
We demonstrate the use of coherent division and recombination of the pulse within an ultrafast laser cavity to manage the nonlinear phase accumulation and scale the output pulse energy. We implement the divided-pulse technique in an ytterbium-doped fiber laser and achieve 16-times scaling of the pulse energy, to generate 6 nJ and 1.4 ps solitons in single mode fiber. Potential extensions of this concept are discussed. PMID:24784100
Optically pulsed electron accelerator
Fraser, J.S.; Sheffield, R.L.
An optically pulsed electron accelerator can be used as an injector for a free electron laser and comprises a pulsed light source, such as a laser, for providing discrete incident light pulses. A photoemissive electron source emits electron bursts having the same duration as the incident light pulses when impinged upon by same. The photoemissive electron source is located on an inside wall of a radiofrequency-powered accelerator cell which accelerates the electron burst emitted by the photoemissive electron source.
Nanosecond light-pulse generator
Novakovskii, M.V.; Stas'ev, V.P.
This paper describes a ruby laser for shadow photography of a spark-discharge channel that produces single pulses with an energy of 10/sup -2/ J, a half-height duration of 1 X 10/sup -9/ sec, and a delay of 6.5 X 10/sup -8/ sec and instability of 5 X 10/sup -9/ relative to the modulating signal. A feature of the described system is the electrical coupling of the square pulse generator, Pockels cell, and low-inductance laser-fired discharger (LFD), which allows a giant pulse to be generated by one cell and part of the energy to be extracted from it. A short delay is obtained due to the short length of the resonator (40 cm). The described system has been used to study the dynamics of spark discharge in a gas at the switching stage. A typical oscillogram of the voltage drop across the discharge gap and shadow photographs of discharge are shown.
C. H. Rohwer; D. P. Laurie
We investigate a recent algorithm, here called a discrete pulse transform (DPT), for the multiresolution analysis of a sequence. A DPT represents a sequence as a sum of pulses, where a pulse is a sequence which is zero everywhere except for a certain number of consecutive elements which have a constant nonzero value. Unlike the discrete Fourier and wavelet transforms,
Pulse transformer design study
H. Aslin
This final report describes the design, development of fabrication techniques, fabrication, and testing of two uniform field, air core pulse transformers. The described transformer design minimizes the volume of dielectric material, which provides turn-to-turn insulation, reduces stray series inductance, and thus improves the transformer high frequency response in comparison to conventional pulse transformers. The described pulse transformers are intended for
Temperature-promoted large-volume solute enrichment in column-switching miniaturized liquid chromatography: determination of an antioxidant.
Molander, Paal; Holm, Anders; Lundanes, Elsa; Hegna, Dag R; Ommundsen, Espen; Greibrokk, Tyge
A two-valve sub-ambient temperature-promoted reversed-phase packed-capillary liquid-chromatography column-switching system has been tailored for sensitive determination of hydrophobic compounds. Such compounds are not easily dissolved in solvent mixtures of non-eluting properties that traditionally are used for solute enrichment in reversed-phase liquid chromatography. Enrichment-column solute focusing of large sample volumes was promoted by use of sub-ambient temperatures only, allowing the use of sample solvents that were stronger or equal to the mobile phase solvent strength. Subsequent column switching and enrichment-column temperature increment provided efficient low-dispersion back-flushed enrichment-column solute desorption onto the analytical column, where the solute was subjected to temperature-programmed gradient action. The antioxidant, Irganox 1076 (octadecyl 3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate) extracted from low density polyethylene with 100% acetonitrile served as a hydrophobic model compound. The mobile phase consisted of acetonitrile containing 10 mM triethylamine and formic acid, and the 0.25 mm id enrichment-column and analytical column in lengths of 27 and 250 mm, respectively, were packed with 3.5 microm Kromasil C18 particles. Sample volumes of up to 500 microL were successfully focused on the enrichment column at 5 degrees C using loading flow rates of up to 40 microL min(-1) prior to temperature programming to 90 degrees C. The concentration limit of detection of Irganox 1076 was 6 ng mL(-1) when using an injection volume of 500 microL. The within-assay precision was in the range 3.5-6.8% (n = 6) while the between-day precision was 7.5% (n = 3) relative standard deviation. The method was linear within the investigated mass range 3-100 ng (R2 = 0.9993). PMID:12173646
Variation of the pulse profile of Hercules X-1
NASA Technical Reports Server (NTRS)
Ohashi, T.; Inoue, H.; Kawai, N.; Koyama, K.; Matsuoka, M.; Mitani, K.; Tanaka, Y.; Nagase, F.; Nakagawa, M.; Kondo, Y.
The X-ray pulsar Her X-1 was observed in an on-state during its 35th cycle of activity in May, 1983 using the gas scintillation proportional counter (GSPC) array of the Tenma X-ray astronomy satellite. The outstanding features observed during the declining phase of the on-state included: a sharp decrease in the main X-ray pulse amplitude; and a steady increase in the column density of cool matter. On the basis of the spectral shape of the pulses, it is suggested that the main phase was attenuated due to electron scattering of the X-ray beam in a highly ionized medium located 3 x 10 to the 8th cm from the neutron star. Near the end of the on-state, the main pulse totally disappeared and a plain sinusoidal profile was observed. The observed pulse profiles are reproduced in graphic form.
Comparison of monolithic silica and polymethacrylate capillary columns for LC.
Moravcovß, Dana; Jandera, Pavel; Urban, Jiri; Planeta, Josef
Organic polymer monolithic capillary columns were prepared in fused-silica capillaries by radical co-polymerization of ethylene dimethacrylate and butyl methacrylate monomers with azobisisobutyronitrile as initiator of the polymerization reaction in the presence of various amounts of porogenic solvent mixtures and different concentration ratios of monomers and 1-propanol, 1,4-butanediol, and water. The chromatographic properties of the organic polymer monolithic columns were compared with those of commercial silica-based particulate and monolithic capillary and analytical HPLC columns. The tests included the determination of H-u curves, column permeabilities, pore distribution by inversed-SEC measurements, methylene and polar selectivities, and polar interactions with naphthalenesulphonic acid test samples. Organic polymer monolithic capillary columns show similar retention behaviour to chemically bonded alkyl silica columns for compounds with different polarities characterized by interaction indices, Ix, but have lower methylene selectivities and do not show polar interactions with sulphonic acids. The commercial capillary and analytical silica gel-based monolithic columns showed similar selectivities and provided symmetrical peaks, indicating no significant surface heterogeneities. To allow accurate characterization of the properties of capillary monolithic columns, the experimental data should be corrected for extra-column contributions. With 0.3 mm ID capillary columns, corrections for extra-column volume contributions are sufficient, but to obtain true information on the efficiency of 0.1 mm ID capillary columns, the experimental bandwidths should be corrected for extra-column contributions to peak broadening. PMID:15354556
Hybrid chirped pulse amplification system
Barty, Christopher P.; Jovanovic, Igor
A hybrid chirped pulse amplification system wherein a short-pulse oscillator generates an oscillator pulse. The oscillator pulse is stretched to produce a stretched oscillator seed pulse. A pump laser generates a pump laser pulse. The stretched oscillator seed pulse and the pump laser pulse are directed into an optical parametric amplifier producing an optical parametric amplifier output amplified signal pulse and an optical parametric amplifier output unconverted pump pulse. The optical parametric amplifier output amplified signal pulse and the optical parametric amplifier output laser pulse are directed into a laser amplifier producing a laser amplifier output pulse. The laser amplifier output pulse is compressed to produce a recompressed hybrid chirped pulse amplification pulse.
Dispersion in retentive pillar array columns.
Yan, Xiaohong; Wang, Qiuwang; Bau, Haim H
The method of volume averaging is applied to estimate the Taylor-Aris dispersion tensor of solute advected in columns consisting of ordered pillar arrays with wall retention of the type used in chromatographic separation. The appropriate closure equations are derived and solved in a unit cell with periodic boundary conditions to obtain the dispersion tensor (or the reduced plate height) as a function of the Peclet number (reduced velocity); pillar pattern, shape and size; partition coefficient; and resistance to mass transfer. The contributions of the velocity profile, the wall adsorption, and the mass transfer resistance to the dispersion tensor are identified and delineated. The model is verified by comparing its predictions and obtaining favorable agreement with results of direct numerical simulations and with experimental data for columns containing ordered pillars. The model is then used to study the effect of pillars' shape and pattern on the longitudinal dispersion coefficient (plate height). PMID:20079500
NSDL National Science Digital Library
Born on a farm in Ontario, William Preston Davies came to the plains of North Dakota at the age of 20. In his early 30s, he began a long career as a journalist, and worked as an editor and writer at the Northwest News, the Grand Forks Plaindealer, and the Grand Forks Herald. In 1930, Davies began writing a daily column called "That Reminds Me". This digital collection from the University of North Dakota's Chester Fritz Library gives users access to his daily insights and observations on North Dakota life. The first column available here dates from April 1930 and the last one is from September 1943. There is nary a subject that Davies doesn't cover, as he winds his way through topics like farm policy, local wit and lore, and Charlie Chaplin.
Rapid method for extracting aldrin, dieldrin, and endrin from visceral material.
Kurhekar, M P; D'souza, F C; Meghal, S K
A simple method is described for purifying aldrin, dieldrin, and endrin from visceral material by using a Celite column. Celite retains all interfering materials including Lipids whereas the chlorinated Insecticides are eluted from the column with n-hexane. This extract can be used directly for gas chromatographic analysis. PMID:1141184
A method using ion chromatography (IC) for the analysis of ferrous (Fe 2+) and ferric (Fe 3+) ions in soil extracts has been developed. This method uses an ion exchange column with detection at 520 nm after post-column derivatization. Selectivity is achieved by using an anionic...
Mechanical end joint for structural columns
NASA Technical Reports Server (NTRS)
Bush, H. G.; Wallsom, R. E.
Connector for tubular struts permits construction of lightweight frames without tools or assembly equipment. Two main components are node fitting and strut element. Components are aleaned approximately and pushed together. Design accommodates reasonable axial and rotational misalignment of nodes and struts. Also, individual columns can be inserted into receptacle and given slight push by operator, trigger pins release ratchet, allowing energy stored in springs to rotate screw into nut in receptacle.
Plastic disproportionate collapse at lost corner columns
Colin GURLEY
This paper deploys an existing method for the simple rigid-plastic hand calculation of slab yield- line mechanisms to address the wider problem of disproportionate collapse at lost columns in multi- storey buildings. Floor systems will be treated as grillages combining torsion-free (Hillerborg) slabs and torsion-free beams. The aim is to achieve an understanding that transcends reliance on non-linear finite element
Pulse-burst operation of standard Nd:YAG lasers
NASA Astrophysics Data System (ADS)
Den Hartog, D. J.; Ambuel, J. R.; Borchardt, M. T.; Reusch, J. A.; Robl, P. E.; Yang, Y. M.
Two standard commercial flashlamp-pumped Nd:YAG lasers have been upgraded to "pulse-burst" capability. Each laser produces a burst of up to fifteen 2 J Q-switched pulses (1064 nm) at repetition rates 1-12.5 kHz. Variable pulse-width drive (0.15-0.39 ms) of the flashlamps is accomplished by IGBT (insulated gate bipolar transistor) switching of electrolytic capacitor banks. Direct control of the laser Pockels cell drive enables optimal pulse energy extraction, and up to four 2 J laser pulses during one flashlamp pulse. These lasers are used in the Thomson scattering plasma diagnostic system on the MST reversed-field pinch to study the dynamic evolution of the electron temperature.
Effects of pulse frequency on the microstructure, composition and optical properties of pulsed dc reactively sputtered vanadium oxide thin films
NASA Astrophysics Data System (ADS)
Dong, Xiang; Wu, Zhiming; Jiang, Yadong; Xu, Xiangdong; Yu, He; Gu, Deen; Wang, Tao
Vanadium oxide (VOx) thin films were prepared on unheated glass substrate by pulsed dc reactive magnetron sputtering using different pulse frequency. Field emission scanning electron microscopy (FESEM), x-ray photoelectron spectroscopy (XPS) and spectroscopic ellipsometry (SE) measurements were made on the deposited VOx films to characterize the microstructure, composition and optical properties, respectively. It was found that under the same discharge power and argon-oxygen atmosphere, with the increase of pulse frequency, the vertical column-like structure in the films will gradually disappear and the ratio of high-valent VOx to low-valent VOx will obviously elevate. Optical parameters of the VOx films have been obtained by fitting the ellipsometric data (? and?) using the Tauc-Lorentz dispersion relation and a multilayer model (air/roughness layer/VOx/glass). The results demonstrated that pulse frequency plays a critical role in determining the transmittance, refractive index, extinction coefficient and optical band gap etc. The correlations between the microstructure, composition, optical properties and pulse frequency are also given by our experiment results. And the mechanisms for the evolution of the microstructure, composition and optical properties with pulse frequency have been discussed. Overall, due to the pulse frequency had a great effect not only on the growth characteristics but also on the optical properties of the VOx films, thus through variation of the pulse frequency during deposition which provide a convenient and efficient approach to control and optimize the performances of the VOx films.
[Spectral investigation of atmospheric pressure plasma column].
Li, Xue-Chen; Chang, Yuan-Yuan; Xu, Long-Fei
Atmospheric pressure plasma column has many important applications in plasma stealth for aircraft. In the present paper, a plasma column with a length of 65 cm was generated in argon at atmospheric pressure by using dielectric barrier discharge device with water electrodes in coaxial configurations. The discharge mechanism of the plasma column was studied by optical method and the result indicates that a moving layer of light emission propagates in the upstream region. The propagation velocity of the plasma bullet is about 0.6 x 10(5) m x s(-1) through optical measurement. Spectral intensity ratios as functions of the applied voltage and driving frequency were also investigated by spectroscopic method. The variation in spectral intensity ratio implies a change in the averaged electron energy. Results show that the averaged electron energy increases with the increase in the applied voltage and the driving frequency. These results have significant values for industrial applications of the atmospheric pressure discharge and have extensive application potentials in stealth for military aircraft. PMID:23016319
Engineering Monosodium Titanate for Adsorption Column Processes
Monosodium titanate (MST) is an inorganic adsorbent powder that effectively removes strontium, plutonium, neptunium, and other trace elements from alkaline high-level waste (HLW) supernate. This work tested one commercial titanate and four general methods to engineer MST into particles large enough to use in adsorption columns. The most successful of the engineered products selected from batch contact and chemical stability testing succeeded in treating 2900 bed volumes (BV) of simulated salt waste containing dissolved plutonium and strontium. There was no detectable strontium breakthrough and only 6 per cent plutonium breakthrough--well within the processing goal--at the end of the demonstration which operated at 5.3 BV/hour. Additional column tests at nominally 15 BV/hr demonstrated similar removal performance. Batch testing of adsorbents used both actual Savannah River Site (SRS) tank supernate as well as simulated salt solutions spiked with strontium, neptunium, and plutonium. In tank waste tests, internal gelation beads produced by the Oak Ridge National Laboratory (ORNL) demonstrated a batch distribution coefficient of 35,000 +/- 4,000 mL/g for plutonium at a phase ratio of 1970 mL/g. In the same batch the sorbent demonstrated a batch distribution coefficient of 99,000 +/- 7,500 mL/g for strontium. These results indicate that this material should be able to process thousands of bed volumes of SRS salt waste before column breakthrough.
Engineering Monosodium Titanate for Adsorption Column Processes
Monosodium titanate is an inorganic adsorbent powder that effectively removes strontium, plutonium, neptunium, and other trace elements from alkaline high-level waste supernate. This work tested one commercial titanate and four general methods to engineer MST into particles large enough to use in adsorption columns. The most successful of the engineered products selected from batch contact and chemical stability testing succeeded in treating 2900 bed volumes of simulated salt waste containing dissolved plutonium and strontium. There was no detectable strontium breakthrough and only 6 percent plutonium breakthrough--well within the processing goal--at the end of the demonstration which operated at 5.3 BV/hour. Additional column tests at nominally 15 BV/hr demonstrated similar removal performance. Batch testing of adsorbents used both actual Savannah River Site tank supernate as well as simulated salt solutions spiked with strontium, neptunium, and plutonium. In tank waste tests, internal gelation beads produced by the Oak Ridge National Laboratory demonstrated a batch distribution coefficient of 35,000 +/- 4,000 mL/g for plutonium at a phase ratio of 1970 mL/g. In the same batch the sorbent demonstrated a batch distribution coefficient of 99,000 +/- 7,500 mL/g for strontium. These results indicate that this material should be able to process thousands of bed volumes of SRS salt waste before column breakthrough.
[Determination of fructooligosaccharides in milk powder using high performance anion-exchange chromatography coupled with pulsed amperometric detection].
Geng, Lijuan; Huang, Junrong; Feng, Feng; Jiang, Pingping; Chu, Xiaogang; Zhang, Feng; Ling, Yun
Fructooligosaccharides (FOS) are usually added in milk powder as a kind of prebiotic. Thus, quantitative analysis of the FOS is very important for the quality control of milk powder. In this study, a simple method for the simultaneous determination of three FOS components with degrees of polymerization (DP) 3-5 in milk powder was developed by high performance anion-exchange chromatography coupled with pulsed amperometric detection (HPAEC-PAD). The samples were extracted with 50% (v/v) ethanol aqueous solution and defatted by an On Guard RP pretreatment column. The separation was performed on a CarboPac PA200 column by gradient elution using deionized water, 0. 2 mol/L NaOH solution and 0. 4 mol/L NaAc solution as the mobile phases. The flow rate was 0. 4 mL/min. The column temperature was 30 ░C; and the injection volume was 25 ĄL. Good linear response was observed in the concentration range of 0.05-10 mg/L (r2 >0. 9993). The limits of quantification were 0. 02, 0. 005 and 0. 02 mg/L for 1-kestose, nystose and fructofuranosyl-nystose, respectively. The mean recoveries varied from 86. 0% to 114. 0% at three spiked levels of 0. 5, 1. 0 and 5. 0 mg/L. The short-chain fructooligosaccharides from inulooligosaccharides (IOS) were successfully separated by the developed HPAEC-PAD method. The method is simple, accurate, sensitive, and helpful for the quality control of milk powder. PMID:25902647
The minimum identifiable quantities of 55 toxic substances have been determined by packed column gas chromatography/Fourier transform infrared spectroscopy (GC/FT-IR) at conditions compatible with environmental extract analysis. Identification of each GC effluent component was ac...
McGlaun, M.
This paper is an introductory discussion of stress pulse phenomena in simple solids and fluids. Stress pulse phenomena is a very rich and complex field that has been studied by many scientists and engineers. This paper describes the behavior of stress pulses in idealized materials. Inviscid fluids and simple solids are realistic enough to illustrate the basic behavior of stress pulses. Sections 2 through 8 deal with the behavior of pressure pulses. Pressure is best thought of as the average stress at a point. Section 9 deals with shear stresses which are most important in studying solids.
Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey
CAR MACHINE SHOP, FIRST FLOOR, DETAIL OF WOOD COLUMN AND INVERTED KING-POST TRUSS TO PROVIDE INCREASED SPAN BETWEEN COLUMNS, LOOKING SOUTH. - Southern Pacific, Sacramento Shops, Car Machine Shop, 111 I Street, Sacramento, Sacramento County, CA
Integrated Thermal and Hydraulic Analysis of Distillation Columns
Samant, K.; Sinclair, I.; Keady, G.
This paper outlines the implementation of column thermal and hydraulic analysis in a simulation environment. The methodology is described using a separations example. Column Thermal Analysis has been discussed in the literature extensively...
Integrated Thermal and Hydraulic Analysis of Distillation ColumnsĀ
Samant, K.; Sinclair, I.; Keady, G.
Integrated Thermal and Hydraulic Analysis of Distillation Columns Ketan Samant, Aspen Technology Ian Sinclair, Aspen Technology Ginger Keady, Aspen Technology This paper outlines the implementation of column thermal and hydraulic analysis in a...
Materialization Strategies in a Column-Oriented DBMS
Abadi, Daniel J.
There has been renewed interest in column-oriented database architectures in recent years. For read-mostly query workloads such as those found in data warehouse and decision support applications, ``column-stores'' have ...
29. View of paired concreteencased columns at joint between beams ...
Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey
29. View of paired concrete-encased columns at joint between beams contrasted against wider single columns. Looking east. - Stillwell Avenue Station, Intersection of Stillwell & Surf Avenues, Brooklyn, Kings County, NY
Query execution in column-oriented database systems
Abadi, Daniel J
There are two obvious ways to map a two-dimension relational database table onto a one-dimensional storage interface: store the table row-by-row, or store the table column-by-column. Historically, database system implementations ...
Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey
6. HISTORIC AMERICAN BUILDINGS SURVEY, INTERIOR SHOWING ORIGINAL GRANITE COLUMNS AND COLUMN BRICKFACED AFTER THE GREAT FIRE 1904 - Old U.S. Appraisers Stores, Gay & Lombard Streets, Baltimore, Independent City, MD
[Scale-up of conical column with 10 degree opening angle as preparative liquid chromatographic column].
Lu, Liejuan; Chen, Jie; Guan, Yafeng
A preparative scale liquid chromatographic column with the conical shape of 10 degrees opening angle was constructed and evaluated. The column was designed with the inlet/outlet diameters of 54/27 mm, the column length of 150 mm and the column volume of 200 mL, and packed with the spherical C18 bonded silica with the particle size of 40-75 microm and the aperture of 11 nm. The mobile phase in the conical column showed a plug like flow profile and plug like chromatographic band shape. For naphthalene, the reduced plate height was about 2.11; the maximum sample load was 2.1 mg or 1.7 mL (10% reduction of plate number), which is 20%, 16% and 19% higher than that of cylindrical one of the same length and volume. As the injection mass increased from 2. 4 mg up to 12 mg, the resolution of ethyl paraben/butyl (R, ) reduced from 2. 14 down to 1.71, and the butyl paraben/naphthalene (Rs3) from 2.91 down to 2.52; the injection volume increased from 3 mL up to 19 mL, Rs2, reduced from 2.23 down to 1.28, and Rs3 from 2.95 down to 2.30, while the peaks were still in symmetric shape without tailing. This characteristic of the column shall benefit for the separation of trace components from matrix. This demonstrated the conical shaped preparative columns would have a broad practical applicability for obtaining pure compounds. PMID:19803133
Development of PI diagrams for FRP strengthened RC columns
Azrul A. Mutalib; Hong Hao
In this study, numerical simulations are performed to construct the Pressure-Impulse (P-I) diagrams for FRP strengthened RC columns to provide correlations between the damage levels of FRP strengthened RC columns and blast loadings. Numerical model of RC columns without or with FRP strengthening is developed using LS-DYNA. The accuracy of the model to simulate RC column responses to blast loads
Cross flow cyclonic flotation column for coal and minerals beneficiation
Lai, Ralph W. (Upper St. Clair, PA); Patton, Robert A. (Pittsburgh, PA)
An apparatus and process for the separation of coal from pyritic impurities using a modified froth flotation system. The froth flotation column incorporates a helical track about the inner wall of the column in a region intermediate between the top and base of the column. A standard impeller located about the central axis of the column is used to generate a centrifugal force thereby increasing the separation efficiency of coal from the pyritic particles and hydrophillic tailings.
Zeptosecond precision pulse shaping.
K÷hler, Jens; Wollenhaupt, Matthias; Bayer, Tim; Sarpe, Cristian; Baumert, Thomas
We investigate the temporal precision in the generation of ultrashort laser pulse pairs by pulse shaping techniques. To this end, we combine a femtosecond polarization pulse shaper with a polarizer and employ two linear spectral phase masks to mimic an ultrastable common-path interferometer. In an all-optical experiment we study the interference signal resulting from two temporally delayed pulses. Our results show a 2?-precision of 300 zs = 300 ū 10(-21) s in pulse-to-pulse delay. The standard deviation of the mean is 11 zs. The obtained precision corresponds to a variation of the arm's length in conventional delay stage based interferometers of 0.45 ┼. We apply these precisely generated pulse pairs to a strong-field quantum control experiment. Coherent control of ultrafast electron dynamics via photon locking by temporal phase discontinuities on a few attosecond timescale is demonstrated. PMID:21716397
Alternative and Efficient Extraction Methods for Marine-Derived Compounds
Grosso, Clara; ValentŃo, PatrĒcia; Ferreres, Federico; Andrade, Paula B.
Marine ecosystems cover more than 70% of the globeÆs surface. These habitats are occupied by a great diversity of marine organisms that produce highly structural diverse metabolites as a defense mechanism. In the last decades, these metabolites have been extracted and isolated in order to test them in different bioassays and assess their potential to fight human diseases. Since traditional extraction techniques are both solvent- and time-consuming, this review emphasizes alternative extraction techniques, such as supercritical fluid extraction, pressurized solvent extraction, microwave-assisted extraction, ultrasound-assisted extraction, pulsed electric field-assisted extraction, enzyme-assisted extraction, and extraction with switchable solvents and ionic liquids, applied in the search for marine compounds. Only studies published in the 21st century are considered. PMID:26006714
Investigation of FRP strengthened circular columns under biaxial bending
Manal K. Zaki
This paper presents the analysis and design of cylindrical reinforced concrete (RC) columns confined with fiber reinforced polymer (FRP) composites. The columns studied are under combined axial loads and biaxial bending moments. The fiber method modeling (FMM) together with finite element analysis (FEA) are adopted to investigate the behavior of such columns. The procedure finds the inclination and depth of
Capillary columns-from London to London in 25 years
L. S. Ettre
The paper presents an overview of the evolution of open tubular (capillary) columns introduced 25 years ago by M.J.E. Golay. This evolution is divided into five stages: the formulation of the theory and the basic work laying down the foundations for future work; learning the influence of the variables on column performance; development of columns with increased surface area; development
Experimental behaviour of recycled aggregate concrete filled steel tubular columns
You-Fu Yang; Lin-Hai Han
This paper describes a series of tests on steel tubular columns of circular and square section filled with normal concrete and recycled aggregate concrete. Thirty specimens, including 24 recycled aggregate concrete filled steel tubular (RACFST) columns and 6 normal concrete filled steel tubular (CFST) columns, were tested to investigate the influence of variations in the tube shape, circular or square,
On the Optimal Design of Columns Against Buckling
Steven J. Coxy; Michael L. Overtonz
We establish existence, derive necessary conditions, and construct and testan algorithm for the maximization of a column's Euler buckling load under a varietyof boundary conditions over a general class of admissible designs. We prove that symmetricclamped--clamped columns possess a positive first eigenfunction and introduce asymmetric rearrangement that does not decrease the column's buckling load. Our necessaryconditions, expressed in the language
Xiangdong Liu; Antonio Nanni
This paper describes a phase of the research program to determine the feasibility of a proposed FRP retrofit method to strengthen the corroded steel columns. This method consists in two steps: wrapping the corroded steel column with open FRP jacket and filling the jacket with expansive light-weight concrete. Seven steel columns were tested in the laboratory with five of them
Time requirements for heteroazeotropic distillation in batch columns
S. Skouras; Sigurd Skogestad
Batch time requirements are provided for the separation of ternary heterogeneous azeotropic mixtures into three pure products in closed batch column configurations. The separations are performed in hybrid processes where distillation is combined with decantation for completing the separation task. Two multivessel column configurations, with and without vapour bypass, and a rectifier column, are compared in terms of time requirements.
Time variation of floc properties in a settling column
K. J Curran; P. S Hill; T. G Milligan
This study investigates the evolution of suspended floc size and settling velocity in an invertible column equipped with photographic and video systems. Nine experiments were performed using 50, 75, and 100 mg dm?3 of marine clay and column inversion times of 0.5, 1, and 2 h. Following inversion, the column was placed in the upright position and the suspension allowed
Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey
24. DETAIL VIEW OF COLUMN #072 DEVIATING FROM VERTICAL IN ROW OF INTACT COLUMNS, LOOKING NORTHEAST TO SOUTHWEST. (NOTE BOLTED BLOCK SCABBED TO COLUMN AS JOIST/TRUSS SUPPORT) - Oakland Army Base, Transit Shed, East of Dunkirk Street & South of Burma Road, Oakland, Alameda County, CA
Interpreting satellite column observations of formaldehyde over tropical South America
Palmer, Paul
-900, Brazil Space-borne column measurements of formaldehyde (HCHO), a high-yield oxidation product of volatile. Here, we interpret observed distributions of HCHO columns from the Global Ozone Monitoring Experiment-long in situ isoprene concentrations and fire-free GOME HCHO columns over a tropical ecosystem. GOME HCHO
Parylene gas chromatographic column for rapid thermal cycling
Hong-seok Noh; Peter J. Hesketh; Gregory C. Frye-Mason
This paper presents a parylene gas chromatographic column with an embedded heating element. The parylene coating on a silicon microchannel and parylene\\/parylene thermal bonding technique were employed to fabricate a parylene column. The heating element is a thin gold film evaporated on the corrugated surface of the parylene column having long and rectangular geometry. Joule heating via the thin gold
G. P. Lignola; A. Prot; G. Manfredi; E. Cosenza
Column jacketing with Fiber Reinforced Polymer (FRP) composites materials has been extensively studied in the last decade to address the issue of seismic upgrade and retrofit of existing Reinforced Concrete (RC) columns. Researchers have mainly focused their attention on solid columns. Very little has been done about hollow cross sections strengthened with FRP. In order to study the behaviour of
The critical temperature of steel columns with restrained thermal elongation
I. Cabrita Neves
The influence of restraint of their thermal elongation on the fire resistance of steel columns is studied. The restraining forces are calculated as a function of steel temperature. The influence of several parameters on the fire resistance is analyzed: stiffness of the structure to which the column belongs; slenderness of the column; and eccentricity of the restraining forces.
Developing the Pulsed Fission-Fusion (PuFF) Engine
NASA Technical Reports Server (NTRS)
Adams, Robert B.; Cassibry, Jason; Bradley, David; Fabisinski, Leo; Statham, Geoffrey
In September 2013 the NASA Innovative Advanced Concept (NIAC) organization awarded a phase I contract to the PuFF team. Our phase 1 proposal researched a pulsed fission-fusion propulsion system that compressed a target of deuterium (D) and tritium (T) as a mixture in a column, surrounded concentrically by Uranium. The target is surrounded by liquid lithium. A high power current would flow down the liquid lithium and the resulting Lorentz force would compress the column by roughly a factor of 10. The compressed column would reach criticality and a combination of fission and fusion reactions would occur. Our Phase I results, summarized herein, review our estimates of engine and vehicle performance, our work to date to model the fission-fusion reaction, and our initial efforts in experimental analysis.
Isolated attosecond pulse generation without the need to stabilize the carrier-envelope phase of driving lasers.
Gilbertson, Steve; Khan, Sabih D; Wu, Yi; Chini, Michael; Chang, Zenghu
Single isolated attosecond pulses can be extracted from a pulse train with an ultrafast gate in the generation target. By setting the gate width sufficiently narrow with the generalized double optical gating, we demonstrate that single isolated attosecond pulses can be generated with any arbitrary carrier-envelope phase value of the driving laser. The carrier-envelope phase only affects the photon flux, not the pulse duration or contrast. Our results show that isolated attosecond pulses can be generated using carrier-envelope phase unstabilized 23 fs pulses directly from chirped pulse amplifiers. PMID:20868162
Effects of PEF-assisted extraction of anthocyanin in red raspberry
Luo Wei; Zhang Ruobing; Wang Liming; Chen Jie; Guan Zhicheng; Liao Xiaojun; Mo Mengbin
Pulsed electric field is a novel non-thermal process technology. It could be applied in the extraction of functional components from plant for its irreversible disintegration on plant cell membrane. PEF treatment caused an irreversible disintegration on the cellular membrane of raspberry cell and the extraction yield of anthocyanins from raspberry was linearly correlated to the treatment pulses of PEF. During
Bioretention column study of bacteria community response to salt-enriched artificial stormwater.
Endreny, Theodore; Burke, David J; Burchhardt, Kathleen M; Fabian, Mark W; Kretzer, Annette M
Cold climate cities with green infrastructure depend on soil bacteria to remove nutrients from road salt-enriched stormwater. Our research examined how bacterial communities in laboratory columns containing bioretention media responded to varying concentrations of salt exposure from artificial stormwater and the effect of bacteria and salt on column effluent concentrations. We used a factorial design with two bacteria treatments (sterile, nonsterile) and three salt concentrations (935, 315, and 80 ppm), including a deionized water control. Columns were repeatedly saturated with stormwater or deionized and then drained throughout 5 wk, with the last week of effluent analyzed for water chemistry. To examine bacterial communities, we extracted DNA from column bioretention media at time 0 and at week 5 and used molecular profiling techniques to examine bacterial community changes. We found that bacterial community taxa changed between time 0 and week 5 and that there was significant separation between taxa among salt treatments. Bacteria evenness was significantly affected by stormwater treatment, but there were no differences in bacterial richness or diversity. Soil bacteria and salt treatments had a significant effect on the effluent concentration of NO, PO, Cu, Pb, and Zn based on ANOVA tests. The presence of bacteria reduced effluent NO and Zn concentrations by as much as 150 and 25%, respectively, while having a mixed effect on effluent PO concentrations. Our results demonstrate how stormwater can affect bacterial communities and how the presence of soil bacteria improves pollutant removal by green infrastructure. PMID:23128752
Characterization of Ascentis RP-Amide column: Lipophilicity measurement and linear solvation energy relationships.
Benhaim, Deborah; Grushka, Eli
This study investigates lipophilicity determination by chromatographic measurements using the polar embedded Ascentis RP-Amide stationary phase. As a new generation of amide-functionalized silica stationary phase, the Ascentis RP-Amide column is evaluated as a possible substitution to the n-octanol/water partitioning system for lipophilicity measurements. For this evaluation, extrapolated retention factors, log k'w, of a set of diverse compounds were determined using different methanol contents in the mobile phase. The use of n-octanol enriched mobile phase enhances the relationship between the slope (S) of the extrapolation lines and the extrapolated log k'w (the intercept of the extrapolation),as well as the correlation between log P values and the extrapolated log k'w (1:1 correlation, r2 = 0.966).In addition, the use of isocratic retention factors, at 40% methanol in the mobile phase, provides a rapid tool for lipophilicity determination. The intermolecular interactions that contribute to the retention process in the Ascentis RP-Amide phase are characterized using the solvation parameter model of Abraham.The LSER system constants for the column are very similar to the LSER constants of the n-octanol/water extraction system. Tanaka radar plots are used for quick visual comparison of the system constants of the Ascentis RP-Amide column and the n-octanol/water extraction system. The results all indicate that the Ascentis RP-Amide stationary phase can provide reliable lipophilic data. PMID:19939395
NASA Technical Reports Server (NTRS)
The use of information from space systems in the operation of extractive industries, particularly in exploration for mineral and fuel resources was reviewed. Conclusions and recommendations reported are based on the fundamental premise that survival of modern industrial society requires a continuing secure flow of resources for energy, construction and manufacturing, and for use as plant foods.
L. Zhang; C. Hoede
In this paper we present a new approach to extract relevant information by knowledge graphs from natural language text. We give a multiple level model based on knowledge graphs for describing template information, and investigate the concept of partial structural parsing. Moreover, we point out that expansion of concepts plays an important role in thinking, so we study the expansion
Controlling output pulse and prepulse in a resonant microwave pulse compressor
NASA Astrophysics Data System (ADS)
Shlapakovski, A.; Artemenko, S.; Chumerin, P.; Yushkov, Yu.
A resonant microwave pulse compressor with a waveguide H-plane-tee-based energy extraction unit was studied in terms of its capability to produce output pulses that comprise a low-power long-duration (prepulse) and a high-power short-duration part. The application of such combined pulses with widely variable prepulse and high-power pulse power and energy ratios is of interest in the research area of electronic hardware vulnerability. The characteristics of output radiation pulses are controlled by the variation of the H-plane tee transition attenuation at the stage of microwave energy storage in the compressor cavity. Results of theoretical estimations of the parameters tuning range and experimental investigations of the prototype S-band compressor (1.5 MW, 12 ns output pulse; ś13.2 dB gain) are presented. The achievable maximum in the prepulse power is found to be about half the power of the primary microwave source. It has been shown that the energy of the prepulse becomes comparable with that of the short-duration (nanosecond) pulse, while the power of the latter decreases insignificantly. The possible range of variation of the prepulse power and energy can be as wide as 40 dB. In the experiments, the prepulse level control within the range of ś10 dB was demonstrated.
Double-pulse THz radiation bursts from laser-plasma acceleration
Bosch, R. A. [Synchrotron Radiation Center, University of Wisconsin-Madison, 3731 Schneider Drive, Stoughton, Wisconsin 53589 (United States)
A model is presented for coherent THz radiation produced when an electron bunch undergoes laser-plasma acceleration and then exits axially from a plasma column. Radiation produced when the bunch is accelerated is superimposed with transition radiation from the bunch exiting the plasma. Computations give a double-pulse burst of radiation comparable to recent observations. The duration of each pulse very nearly equals the electron bunch length, while the time separation between pulses is proportional to the distance between the points where the bunch is accelerated and where it exits the plasma. The relative magnitude of the two pulses depends upon by the radius of the plasma column. Thus, the radiation bursts may be useful in diagnosing the electron bunch length, the location of the bunch's acceleration, and the plasma radius.
Calculation of CO2 column heights in depleted gas fields from known pre-production gas column heights
Calculation of CO2 column heights in depleted gas fields from known pre-production gas column heights M. Naylor*, M. Wilkinson, R.S. Haszeldine School of GeoSciences, University of Edinburgh, EH9 3JW fields Column height a b s t r a c t Depleted gas fields have been identified as potential targets for CO
Irradiation records in regolith materials, II: Solar wind and solar energetic particle components in helium, neon, and argon extracted from single lunar mineral grains and from the Kapoeta howardite by stepwise pulse heating
NASA Astrophysics Data System (ADS)
Palma, R. L.; Becker, R. H.; Pepin, R. O.; Schlutter, D. J.
High-resolution stepped heating has been used to extract light noble gases implanted in a suite of 13 individual lunar ilmenite and iron grains and in the Kapoeta howardite by solar wind (SW) and solar energetic particle (SEP) irradiation. Isotopic analyses of gases evolved at low temperatures from the lunar grains confirm the neon and argon compositions obtained by Pepin et al. (Pepin R. O., Becker R. H., and Schlutter D. J., "Irradiation records in regolith materials, I: Isotopic compositions of solar-wind neon and argon in single lunar regolith grains", Geochim. Cosmochim. Acta63, 2145-2162, 1999) in an initial study of 11 regolith grains, primarily ilmenites. Combination of the data sets from both investigations yields 20Ne/ 22Ne = 13.85 ▒ 0.04, 21Ne/ 22Ne = 0.0334 ▒ 0.0003, and 36Ar/ 38Ar = 5.80 ▒ 0.06 for the lunar samples; the corresponding 36Ar/ 38Ar ratio in Kapoeta is 5.74 ▒ 0.06. The neon ratios agree well with those measured by Benkert et al. (Benkert J.-P., Baur H., Signer P., and Wieler R., "He, Ne, and Ar from the solar wind and solar energetic particles in lunar ilmenites and pyroxenes", J. Geophys. Res. (Planets)98, 13147-13162, 1993) in gases extracted from bulk lunar ilmenite samples by stepped acid etching and attributed by them to the SW. The 36Ar/ 38Ar ratios, however, are significantly above both Benkert et al.'s (1993) proposed SW value of 5.48 ▒ 0.05 and a later estimate of 5.58 ▒ 0.03 from an acid-etch analysis of Kapoeta (Becker R. H., Schlutter D. J., Rider P. E., and Pepin R. O., "An acid-etch study of the Kapoeta achondrite: Implications for the argon-36/argon-38 ratio in the solar wind", Meteorit. Planet. Sci.33, 109-113, 1998). We believe, for reasons discussed here and in our earlier report, that 5.80 ▒ 0.06 ratio most nearly represents the wind composition. The 3He/ 4He ratio in low-temperature gas releases, not measured in the first particle suite, is found in several grains to be indistinguishable from Benkert et al.'s (1993) SW estimate. Elemental ratios of He, Ne, and Ar initially released from grain-surface SW implantation zones are solar-like, as found earlier by Pepin et al. (1999). Gases evolved from these reservoirs at higher temperatures show evidence for perturbations from solar elemental compositions by prior He loss, thermal mobilization of excess Ne from fractionated SW components, or both. Attention in this second investigation was focused on estimating the isotopic compositions of both the SW and the more deeply sited SEP components in regolith grains. Several high-temperature "isotopic plateaus" - approximately constant isotopic ratios in gas fractions released over a number of consecutive heating steps - were observed in the close vicinities of the SEP ratios for He, Ne, and Ar reported by Benkert et al. (1993). Arguments presented in the text suggest that these plateaus are relatively free of interferences from multicomponent mixing artifacts that can mimic pure component signatures. Average SEP compositions derived from the stepped-heating plateau measurements are in remarkable agreement with the Z³rich acid-etch values for all three gases.
Environmental polychlorinated biphenyls: Acute toxicity of landfill soil extract to female prepubertal rats
L. G. Hansen; M.-H. Li; A. Saeed; B. Bush
Subsurface soil from a National Priorities List landfill containing about 2.5% polychlorinated biphenyls (PCBs) was extracted and the extract cleaned by Florisil« slurry and alumina column chromatography. The refined extract contained 48 mg\\/mL PCB, mainly trichlorobiphenyls and tetrachlorobiphenyls, traces of polychlorinated naphthalenes, 125 Ąg\\/mL 2,2-bis-p-chlorophenyl-1, 1-dichloroethylene (DDE), and low levels of chlorinated dibenzofurans. The refined extract was dissolved in corn
Antioxidant activity and phenolic composition of sumac ( Rhus coriaria L.) extracts
M. Kosar; B. Bozan; F. Temelli; K. H. C. Baser
Antioxidant activity and phenolic compounds of sumac extracts were investigated. Sumac was extracted in methanol and subjected to solvent¢solvent partitioning to yield two fractions as ethyl acetate and aqueous. Methanol extract was further fractioned over Sephadex LH-20 column. Antioxidant activity of extracts and fractions were screened using ferric thiocyanate and DPPH radical scavenging methods. Phenolic composition of active fraction(s) was
Carter, P.; Peglow, S.
This paper is an introduction to the PulseSoar concept. PulseSoar is a hypervelocity airplane that uses existing airport facilities and current technologies to fly at the very edge of space. It will be shown that PulseSoar can fly between any two points on the globe in less than two hours with fuel efficiency exceeding current state of the art commercial airliners. In addition, it will be shown that PulseSoar avoids environmental issues concerning the ozone layer and sonic booms because of its unique flight profile. All of this can be achieved with current technology. PulseSoar does not require the development of enabling technology. It is a concept which can be demonstrated today. The importance of this idea goes beyond the technical significance`s of PulseSoar in terms of feasibility and performance. PulseSoar could provide a crucial economic advantage to America`s largest export market: commercial aircraft. PulseSoar is a breakthrough concept for addressing the emerging markets of long range and high speed aircraft. Application of PulseSoar to commercial transport could provide the US Aerospace industry a substantial lead in offering high speed/long range aircraft to the world`s airlines. The rapid emergence of a US developed high speed aircraft could also be important to our competitiveness in the Pacific Rim and South American economies. A quick and inexpensive demonstration vehicle is proposed to bang the concept to reality within two years. This discussion will address all the major technical subjects encompassed by PulseSoar and identifies several near-term, and low risk, applications which may be further explored with the initial demonstration vehicle. What is PulseSoar? PulseSoar could enable high speed, high altitude and long range flight without many of the difficulties encountered by traditional hypersonic vehicles.
High voltage pulse conditioning
Springfield, Ray M. (Sante Fe, NM); Wheat, Jr., Robert M. (Los Alamos, NM)
Apparatus for conditioning high voltage pulses from particle accelerators in order to shorten the rise times of the pulses. Flashover switches in the cathode stalk of the transmission line hold off conduction for a determinable period of time, reflecting the early portion of the pulses. Diodes upstream of the switches divert energy into the magnetic and electrostatic storage of the capacitance and inductance inherent to the transmission line until the switches close.
Sheely, W.F.
Solid state welding techniques are an alternative to fusion welding. Two solid state welding techniques are pulsed magnetic welding and explosive bonding. Both achieve bonds by impacting the metals to be joined at high velocity. Development of the pulsed magnetic welding process by Hanford Engineers for fuel fabrication may make this process useful for a variety of other applications. Hanford engineers have developed advanced equipment for pulsed magnetic welding and have defined conditions for reliably welding stainless steel fuel pins using this equipment.
Extraction and identification of flavonoids from parsley extracts by HPLC analysis
NASA Astrophysics Data System (ADS)
Stan, M.; Soran, M. L.; Varodi, C.; Lung, I.
Flavonoids are phenolic compounds isolated from a wide variety of plants, and are valuable for their multiple properties, including antioxidant and antimicrobial activities. In the present work, parsley (Petroselinum crispum L.) extracts were obtained by three different extraction techniques: maceration, ultrasonic-assisted and microwave-assisted solvent extractions. The extractions were performed with ethanol-water mixtures in various ratios. From these extracts, flavonoids like the flavones apigenin and luteolin, and the flavonols quercetin and kaempferol were identified using an HPLC Shimadzu apparatus equipped with PDA and MS detectors. The separation method involved a gradient step. The mobile phase consisted of two solvents: acetonitrile and distilled water with 0.1% formic acid. The separation was performed on a RP-C18 column.
Critical pulse power components
Sarjeant, W.J.; Rohwein, G.J.
Critical components for pulsed power conditioning systems will be reviewed. Particular emphasis will be placed on those components requiring significant development efforts. Capacitors, for example, are one of the weakest elements in high-power pulsed systems, especially when operation at high-repetition frequencies for extended periods of time are necessary. Switches are by far the weakest active components of pulse power systems. In particular, opening switches are essentially nonexistent for most applications. Insulaton in all systems and components requires development and improvement. Efforts under way in technology base development of pulse power components will be discussed.
NASA Astrophysics Data System (ADS)
Matsubara, Yoichi
The pulse tube refrigerator is one of the regenerative cycle refrigerators such as Stirling cycle or Gifford-McMahon cycle which gives the cooling temperature below 150 K down to liquid helium temperature. In 1963, W. E. Gifford invented a simple refrigeration cycle which is composed of compressor, regenerator and simple tube named as pulse tube which gives a similar function of the expander in Stirling or Gifford-McMahon cycle. The thermodynamically performance of this pulse tube refrigerator is inferior to that of other regenerative cycles. In 1984, however, Mikulin and coworkers made a significant advance in pulse tube configuration called as orifice pulse tube. After this, several modifications of the pulse tube hot end configuration have been developed. With those modifications, the thermodynamic performance of the pulse tube refrigerator became the same order to that of Stirling and Gifford-McMahon refrigerator. This article reviews the brief history of the pulse tube refrigerator development in the view point of its thermodynamically efficiency. Simplified theories of the energy flow in the pulse tube have also been described.
Direct probing of chromatography columns by laser-induced fluorescence
NASA Astrophysics Data System (ADS)
McGuffin, V. L.
This report summarizes the progress and accomplishments of this research project from 1 Sep. 1989 to 28 Feb. 1993. During this period, we have accomplished all of the primary scientific objectives of the research proposal: (1) constructed and evaluated a laser-induced fluorescence detection system that allows direct examination of the chromatographic column, (2) examined nonequilibrium processes that occur upon solute injection and elution, (3) examined solute retention in liquid chromatography as a function of temperature and pressure, (4) examined solute zone dispersion in liquid chromatography as a function of temperature and pressure, and (5) developed appropriate theoretical models to describe these phenomena. In each of these studies, substantial knowledge has been gained of the fundamental processes that are responsible for chromatographic separations. In addition to these primary research objectives, we have made significant progress in three related areas: (1) examined pyrene as a fluorescent polarity probe in supercritical fluids and liquids as a function of temperature and pressure, (2) developed methods for the class-selective identification of polynuclear aromatic hydrocarbons in coal-derived fluids by microcolumn liquid chromatography with fluorescence quenching detection, and (3) developed methods for the determination of saturated and unsaturated (including omega-3) fatty acids in fish oil extracts by microcolumn liquid chromatography with laser-induced fluorescence detection. In these studies, the advanced separation and detection techniques developed in our laboratory are applied to practical problems of environmental and biomedical significance.
NSDL National Science Digital Library
Teachers' Domain presents this interactive, adapted from the University of Nebraska's Plant and Soil Science eLibrary, with reading material and animations to help students learn the basics of DNA extraction. The lesson is divided into and introduction and the four processes involved: cell lysis, dismantling the cell membrane, removing unwanted cell parts, and precipitating the DNA. On the site, visitors will also find a supplemental background essay, discussion questions, and standards alignment from Teachers' Domain.
Transient groundwater chemistry near a river: Effects on U(VI) transport in laboratory column experiments
Yin, Jun; Haggerty, Roy; Stoliker, Deborah L.; Kent, Douglas B.; Istok, Jonathan D.; Greskowiak, Janek; Zachara, John M.
In the 300 Area of a U(VI)-contaminated aquifer at Hanford, Washington, USA, inorganic carbon and major cations, which have large impacts on U(VI) transport, change on an hourly and seasonal basis near the Columbia River. Batch and column experiments were conducted to investigate the factors controlling U(VI) adsorption/desorption by changing chemical conditions over time. Low alkalinity and low Ca concentrations (Columbia River water) enhanced adsorption and reduced aqueous concentrations. Conversely, high alkalinity and high Ca concentrations (Hanford groundwater) reduced adsorption and increased aqueous concentrations of U(VI). An equilibrium surface complexation model calibrated using laboratory batch experiments accounted for the decrease in U(VI) adsorption observed with increasing (bi)carbonate concentrations and other aqueous chemical conditions. In the column experiment, alternating pulses of river and groundwater caused swings in aqueous U(VI) concentration. A multispecies multirate surface complexation reactive transport model simulated most of the major U(VI) changes in two column experiments. The modeling results also indicated that U(VI) transport in the studied sediment could be simulated by using a single kinetic rate without loss of accuracy in the simulations. Moreover, the capability of the model to predict U(VI) transport in Hanford groundwater under transient chemical conditions depends significantly on the knowledge of real-time change of local groundwater chemistry.
[Contrastive study on dynamic spectrum extraction method].
Li, Gang; Zhou, Mei; Wang, Hui-quan; Xiong, Chan; Lin, Ling
Dynamic spectrum method extracts the absorbance of the artery pulse blood with some wavelengths. The method can reduce some influence such as measurement condition, individual difference and spectrum overlap. It is a new way for noninvasive blood components detection However, how to choose a dynamic spectrum extraction method is one of the key links for the weak ingredient spectrum signal. Now there are two methods to extract the dynamic spectral signal-frequency domain analysis and single-trial estimation in time domain In the present research, comparison analysis and research on the two methods were carrued out completely. Theoretical analysis and experimental results show that the two methods extract the dynamic spectrum from different angles. But they are the same in essence--the basic principle of dynamic spectrum, the signal statistical and average properties. With the pulse wave of relative stable period and amplitude, high precision dynamic spectrum can be obtained by the two methods. With the unstable pulse wave due to the influence of finger shake and contact-pressure change, the dynamic spectrum extracted by single-trial estimation is more accurate than the one by frequecy domain analysis. PMID:22827082
Differential extraction of axonally transported proteoglycans
Elam, J.S. (Florida State Univ., Tallahassee (USA))
Axonally transported proteoglycans were differentially solubilized by a sequence of extractions designed to infer their relationship to nerve terminal membranes. Groups of goldfish were injected unilaterally with 35SO4 and contralateral optic tecta containing axonally transported molecules were removed 16 h later. Tecta were homogenized in isotonic buffer and centrifuged at 100,000 g for 60 min to create a total supernatant fraction. Subsequent homogenizations followed by recentrifugation were with hypotonic buffer (lysis extract), 1 M NaCl, Triton X-100 or alternatively Triton-1 M NaCl. Populations of proteoglycans in each extract were isolated on DEAE ion exchange columns and evaluated for content of glycosaminoglycans (GAGs). Results show the distribution of transported proteoglycans to be 26.3% total soluble, 13.7% lysis extract, 13.8% NaCl extract, 12.2% Triton extract, and 46.2% Triton-NaCl extract. Proteoglycans from all fractions contained heparan sulfate as the predominant GAG, with lesser amounts of chondroitin (4 or 6) sulfate. The possible localizations of transported proteoglycans suggested by the extraction results are discussed.
Comparison of automated pre-column and post-column analysis of amino acid oligomers
NASA Technical Reports Server (NTRS)
Chow, J.; Orenberg, J. B.; Nugent, K. D.
It has been shown that various amino acids will polymerize under plausible prebiotic conditions on mineral surfaces, such as clays and soluble salts, to form varying amounts of oligomers (n = 2-6). The investigations of these surface reactions required a quantitative method for the separation and detection of these amino acid oligomers at the picomole level in the presence of nanomole levels of the parent amino acid. In initial high-performance liquid chromatography (HPLC) studies using a classical postcolumn o-phthalaldehyde (OPA) derivatization ion-exchange HPLC procedure with fluorescence detection, problems encountered included lengthy analysis time, inadequate separation and large relative differences in sensitivity for the separated species, expressed as a variable fluorescent yield, which contributed to poor quantitation. We have compared a simple, automated, pre-column OPA derivatization and reversed-phase HPLC method with the classical post-column OPA derivatization and ion-exchange HPLC procedure. A comparison of UV and fluorescent detection of the amino acid oligomers is also presented. The conclusion reached is that the pre-column OPA derivatization, reversed-phase HPLC and UV detection produces enhanced separation, improved sensitivity and faster analysis than post-column OPA derivatization, ion-exchange HPLC and fluorescence detection.
Sweet and Sour: Attenuating Sulfidogenesis in an Advective Flow Column System with Perchlorate or Nitrate Treatment
NASA Astrophysics Data System (ADS)
Engelbrektson, A. L.; Hubbard, C. G.; Piceno, Y.; Boussina, A.; Jin, Y.; Dubinsky, E. A.; Tom, L.; Hu, P.; Conrad, M. E.; Anderson, G. L.; Coates, J. D.
Hydrogen sulfide (H2S) biogenesis in oil reservoirs is a primary cause of souring and of associated costs in reservoir and pipeline maintenance. In addition to the corrosive effects of the H2S itself, abiotic and biological oxidation also generates sulfuric acid, further degrading metallic surfaces. Amending these environments with perchlorate (ClO4-) resolves these problems by inhibition of biological sulfate reduction and re-oxidation of H2S to elemental sulfur by dissimilatory (per)chlorate reducing bacteria (DPRB). Triplicate flow through columns packed with San Francisco bay sediment were flushed with bay water ([SO4=] = 25-30 mM) containing yeast extract with 50 mM inhibitor concentrations (NO3-or ClO4-) decreasing to 25 mM and finally 12.5 mM. Influent and effluent geochemistry was monitored and DNA was prepared from the sediment bed for microbial community analysis. Souring was reversed by both treatments (at 50 mM) compared to the control columns that had no ion addition. Nitrate began to re-sour when treatment concentration was decreased to 25 mM but treatment had to be decreased to 12.5 mM before the perchlorate treated columns began to re-sour. However, the treated columns re-soured to a lesser extent than the control columns. Phylochip microbial community analyses indicated microbial community shifts and phylogenetic clustering by treatment. Isotopic analysis of sulfate showed trends that broadly agreed with the geochemistry but also suggested further sulfur cycling was occurring. This study indicates that perchlorate shows great promise as an inhibitor of sulfidogenesis in natural communities and provides insight into which organisms are involved in this process.
Quantitative analysis of three chiral pesticide enantiomers by high-performance column liquid chromatography.
Wang, Peng; Liu, Donghui; Gu, Xu; Jiang, Shuren; Zhou, Zhiqiang
Methods for the enantiomeric quantitative determination of 3 chiral pesticides, paclobutrazol, myclobutanil, and uniconazole, and their residues in soil and water are reported. An effective chiral high-performance liquid chromatographic (HPLC)-UV method using an amylose-tris(3,5-dimethylphenylcarbamate; AD) column was developed for resolving the enantiomers and quantitative determination. The enantiomers were identified by a circular dichroism detector. Validation involved complete resolution of each of the 2 enantiomers, plus determination of linearity, precision, and limit of detection (LOD). The pesticide enantiomers were isolated by solvent extraction from soil and C18 solid-phase extraction from water. The 2 enantiomers of the 3 pesticides could be completely separated on the AD column using n-hexane isopropanol mobile phase. The linearity and precision results indicated that the method was reliable for the quantitative analysis of the enantiomers. LODs were 0.025, 0.05, and 0.05 mg/kg for each enantiomer of paclobutrazol, myclobutanil, and uniconazole, respectively. Recovery and precision data showed that the pretreatment procedures were satisfactory for enantiomer extraction and cleanup. This method can be used for optical purity determination of technical material and analysis of environmental residues. PMID:18980112
Comparison of two column characterisation systems based on pharmaceutical applications.
Haghedooren, Erik; Nķmeth, Tamßs; Dragovic, Sanja; Noszßl, Bķla; Hoogmartens, Jos; Adams, Erwin
A useful column characterisation system should help chromatographers to select the most appropriate column to use, e.g. when a particular chromatographic column is not available or when facing the dilemma of selecting a suitable column for analysis according to an official monograph. Official monographs of the European Pharmacopoeia and the United States Pharmacopeia are not allowed to mention the brand name of the stationary phase used for the method development. Also given the overwhelming offer of several hundreds of commercially available reversed-phase liquid chromatographic columns, the choice of a suitable column could be difficult sometimes. To support rational column selection, a column characterisation study was started in our laboratory in 2000. In the same period, Euerby et al. also developed a column characterisation system, which is now released as Column Selector by ACD/Labs. The aim of this project was to compare the two existing column characterisation systems, i.e. the KUL system and the Euerby system. Other research groups active in this field will not be discussed here. Euerby et al. developed a column characterisation system based on 6 test parameters, while the KUL system is based on 4 chromatographic parameters. Comparison was done using a set of 63 columns. For 7 different pharmaceutical separations (fluoxetine, gemcitabine, erythromycin, tetracycline, tetracaine, amlodipine and bisacodyl), a ranking was built based on an F-value (KUL method) or Column Difference Factor value (Euerby method) versus a (virtual) reference column. Both methods showed a similar ranking. The KUL and Euerby methods do not perfectly match, but they yield very similar results, allowing with a relatively high certainty, the selection of similar or dissimilar columns as compared to a reference column. An analyst that uses either of the two methods, will end up with a similar ranking. From a practical point of view, it must be noted that the KUL method only includes 4 parameters and 3 chromatographic methods compared to 6 parameters and 4 methods for the Euerby method. Hence, the time needed to determine the chromatographic properties of a column is shorter for the KUL approach. Access to the KUL method also requires no download procedures. PMID:18295221
Opportunities in pulse combustion
Brenchley, D.L.; Bomelburg, H.J.
In most pulse combustors, the combustion occurs near the closed end of a tube where inlet valves operate in phase with the pressure amplitude variations. Thus, within the combustion zone, both the temperature and the pressure oscillate around a mean value. However, the development of practical applications of pulse combustion has been hampered because effective design requires the right combination of the combustor's dimensions, valve characteristics, fuel/oxidizer combination, and flow pattern. Pulse combustion has several additional advantages for energy conversion efficiency, including high combustion and thermal efficiency, high combustion intensity, and high convective heat transfer rates. Also, pulse combustion can be self-aspirating, generating a pressure boost without using a blower. This allows the use of a compact heat exchanger that may include a condensing section and may obviate the need for a chimney. In the last decade, these features have revived interest in pulse combustion research and development, which has resulted in the development of a pulse combustion air heater by Lennox, and a pulse combustion hydronic unit by Hydrotherm, Inc. To appraise this potential for energy savings, a systematic study was conducted of the many past and present attempts to use pulse combustion for practical purposes. The authors recommended areas where pulse combustion technology could possibly be applied in the future and identified areas in which additional R and D would be necessary. Many of the results of the study project derived from a special workshop on pulse combustion. This document highlights the main points of the study report, with particular emphasis on pulse combustion application in chemical engineering.
Gradient ascent pulse engineering for rapid exchange saturation transfer
NASA Astrophysics Data System (ADS)
Rancan, G.; Nguyen, T. T.; Glaser, S. J.
Efforts in the clinical translation of the paraCEST contrast agent Yb-HPDO3A have prompted an investigation into saturation pulse optimality under energy constraints. The GRAPE algorithm has been adapted and implemented for saturation pulse optimization with chemical exchange. The flexibility of the methodology, both in extracting the microscopical parameter ensemble for the algorithm as well as in determining the characteristics of this new class of rising amplitude waveforms allows rapid testing and implementation. Optimal pulses achieve higher saturation efficiencies than the continuous wave gold standard for rapid and especially for variable exchange rates, as brought about by pH-catalysis. Gains of at least 5-15% without any tradeoff have been confirmed both on a spectrometer and on a clinical imager. Pool specific solutions, with pulses optimized for a specific exchange rate value, additionally increase the flexibility of the CEST ratiometric analysis. A simple experimental approach to determine close to optimal triangular pulses is presented.
Transport of sulfadiazine in soil columns Ś Experiments and modelling approaches
NASA Astrophysics Data System (ADS)
Wehrhan, Anne; Kasteel, Roy; Simunek, Jirka; Groeneweg, Joost; Vereecken, Harry
Antibiotics, such as sulfadiazine, reach agricultural soils directly through manure of grazing livestock or indirectly through the spreading of manure or sewage sludge on the field. Knowledge about the fate of antibiotics in soils is crucial for assessing the environmental risk of these compounds, including possible transport to the groundwater. Transport of 14C-labelled sulfadiazine was investigated in disturbed soil columns at a constant flow rate of 0.26 cm h - 1 near saturation. Sulfadiazine was applied in different concentrations for either a short or a long pulse duration. Breakthrough curves of sulfadiazine and the non-reactive tracer chloride were measured. At the end of the leaching period the soil concentration profiles were determined. The peak maxima of the breakthrough curves were delayed by a factor of 2 to 5 compared to chloride and the decreasing limbs are characterized by an extended tailing. However, the maximum relative concentrations differed as well as the eluted mass fractions, ranging from 18 to 83% after 500 h of leaching. To identify relevant sorption processes, breakthrough curves of sulfadiazine were fitted with a convective-dispersive transport model, considering different sorption concepts with one, two and three sorption sites. Breakthrough curves can be fitted best with a three-site sorption model, which includes two reversible kinetic and one irreversible sorption site. However, the simulated soil concentration profiles did not match the observations for all of the used models. Despite this incomplete process description, the obtained results have implications for the transport behavior of sulfadiazine in the field. Its leaching may be enhanced if it is frequently applied at higher concentrations.
Pulse transformer characterization
W. H. P. Mosterdijk
The pulse transformer at TNO PML-Pulse Physics, Delft, is characterized. It constitutes the final step of an energy compression system (Kapitza facility) which can amplify the current up to 24 times, and consists of a primary single layer winding of 24 turns enclosed in a secondary winding. There is a sine wave current source with adjustable frequencies for the characterization.
Gebhard Moritz
Up to now, only one synchrotron (Nuclotron at JINR, Dubna) is equipped with fast-pulsed superconducting magnets. The demand for high beam intensities leads to the requirement of fast-pulsed magnets for synchrotrons. An example is the proposed international 'Facility for Antiproton and Ion Research' (FAIR) at GSI, which will consist of two synchrotrons in one tunnel, and several storage rings. The
J. Vanacken; L. Liang; K. Rosseel; W. Boon; F. Herlach
In order to design pulsed field magnets with internal reinforcement, the construction parameters (material selection, thickness of reinforcements, etc.) must be optimized. Therefore we have combined in a single, user-friendly package the different aspects of pulsed magnet design by means of a VISUAL BASIC shell. At the basis of the program are the three FORTRAN codes, which calculate the field
Pulsed Fission Propulsion Concept
NASA Technical Reports Server (NTRS)
In the 1960's U.S. Government laboratories, under Project Orion, investigated a pulsed nuclear fission propulsion system. Small nuclear pulse units would be sequentially discharged from the aft end of the vehicle. A blast shield and shock absorber system would protect the crew and convert the shock loads into a continuous propulsive force.
Pulsed Fission Propulsion Concept
NASA Technical Reports Server (NTRS)
In the 1960's U.S. Government laboratories, under Project Orion, investigated a pulsed nuclear fission propulsion system. Small nuclear pulse units would be sequentially discharged from the aft end of the vehicle. A blast shield and shock absorber system would protect the crew and convert the shock loads into a continuous propusive force.
Pulse phase infrared thermography
X. Maldague; S. Marinetti
In this paper a novel approach is proposed which combines simultaneously advantagesboth of pulse (PT) and modulated (MT) infrared thermography. In a nondestructive evaluationperspective, the specimen is pulse-heated as in PT and the mix of frequencies ofthe thermal waves launched into the specimen are unscrambled by performing the Fouriertransform of the temperature evolution over the field of view. Of interest
W. F. Weldon; M. D. Driga; H. H. Woodson
This invention relates to an electromechanical energy converter with inertial energy storage. The device, a single phase, two or multi-pole alternator with stationary field coils, and a rotating armature is provided. The rotor itself may be of laminated steel for slower pulses or for faster pulses should be nonmagnetic and electrically nonconductive in order to allow rapid penetration of the
W. F. Weldon; M. D. Driga; H. H. Woodson
This invention relates to an electromechanical energy converter with inertial energy storage. The device, a single phase, two or multi-pole alternator with stationary field coils, and a rotating armature is provided. The rotor itself may be of laminated steel for slower pulses or for faster pulses should be nonmagnetic and electrically nonconductive in order to allow rapid penetration of the
Howard E. Brandt
The goal of the Intense Microwave Pulses III conference was to present and critically assess new and innovative ideas, together with recent advances, in the generation and transmission of intense microwave pulses. Significant advances were reported on Super-Reltron source development. Also presented were numerous results of research on high-power klystron oscillators and amplifiers. Results of preliminary experimental studies were presented
Magnetic pulse welding technology
Ahmad K. Jassim
In this paper, the benefits of using Magnetic Pulse machine which is belong to Non-conventional machine instead of conventional machine. Magnetic Pulse Technology is used for joining dissimilar metals, and for forming and cutting metals. It is a non contact technique. Magnetic field is used to generate impact magnetic pressure for welding and forming the work piece by converted the
NASA Technical Reports Server (NTRS)
Hruby, Vladimir J. (Inventor); Pote, Bruce M. (Inventor); Gamero-Castano, Manuel (Inventor)
A pulsed Hall thruster system includes a Hall thruster having an electron source, a magnetic circuit, and a discharge chamber; a power processing unit for firing the Hall thruster to generate a discharge; a propellant storage and delivery system for providing propellant to the discharge chamber and a control unit for defining a pulse duration .tau.<0.1d.sup.3.rho./m, where d is the characteristic size of the thruster, .rho. is the propellant density at standard conditions, and m is the propellant mass flow rate for operating either the power processing unit to provide to the Hall thruster a power pulse of a pre-selected duration, .tau., or operating the propellant storage and delivery system to provide a propellant flow pulse of duration, .tau., or providing both as pulses, synchronized to arrive coincidentally at the discharge chamber to enable the Hall thruster to produce a discreet output impulse.
Pulse-burst laser systems for fast Thomson scattering (invited)a)
NASA Astrophysics Data System (ADS)
Den Hartog, D. J.; Ambuel, J. R.; Borchardt, M. T.; Falkowski, A. F.; Harris, W. S.; Holly, D. J.; Parke, E.; Reusch, J. A.; Robl, P. E.; Stephens, H. D.; Yang, Y. M.
Two standard commercial flashlamp-pumped Nd:YAG (YAG denotes yttrium aluminum garnet) lasers have been upgraded to "pulse-burst" capability. Each laser produces a burst of up to 15 2 J Q-switched pulses (1064 nm) at repetition rates of 1-12.5 kHz. Variable pulse-width drive (0.15-0.39 ms) of the flashlamps is accomplished by insulated gate bipolar transistor (IGBT) switching of electrolytic capacitor banks. Direct control of the laser Pockels cell drive enables optimal pulse energy extraction, and up to four 2 J laser pulses during one flashlamp pulse. These lasers are used in the Thomson scattering plasma diagnostic system on the MST reversed-field pinch to record the dynamic evolution of the electron temperature profile and temperature fluctuations. To further these investigations, a custom pulse-burst laser system with a maximum pulse repetition rate of 250 kHz is now being commissioned.
HPLC determination of the flavonoid glycosides from Betulae folium extracts
P. G. Pietta; P. L. Mauri; E. Manera; P. L. Ceva
The main flavonoid glycosides ofBetulae folium extracts (quercetin-3-glucuronide, myricetin-3-galactoside, hyperosid, quercetin-3-arabinoside and quercetin-3-rhamnoside) have been separated by isocratic elution on a C18 Aquapore RP-300 column. Elution was performed with 17% isopropanol at pH 6.2 confirming the validity of this eluent for the analysis of the flavonoid glycosides.
The Microbial World: Winogradsky Column- Perpetual Life in a Tube
NSDL National Science Digital Library
Jim Deacon
This Winogradsky column web page is designed to teach undergraduate students a simple model system of nutrient cycling in natural waters. It includes a physical description of the column and explains how the column can be used to demonstrate metabolic diversity of prokaryotes, how microorganisms occupy highly specific microsites according to their environmental tolerances and their carbon and energy requirements, and how mineral elements are cycled in natural environments. Artistic illustrations and images illustrate the interdependent roles of microorganisms.
Temperature¢enthalpy curve for energy targeting of distillation columns
Santanu Bandyopadhyay; Ranjan K. Malik; Uday V. Shenoy
The temperature¢enthalpy (T¢H) diagram of a distillation column at practical near-minimum thermodynamic condition (PNMTC) or the column grand composite curve (CGCC) is a useful representation for energy targeting studies and may be generated from a converged simulation of a base-case column design. The calculation procedure for the CGCC involves determination of the net enthalpy deficit at each stage by generating
Behavior of square concrete columns reinforced with Prefabricated Cage System
Mohammad ShamsaiHalil Sezen; Halil Sezen
Behavior of normal strength concrete columns reinforced with a new reinforcement, termed Prefabricated Cage System (PCS) is\\u000a investigated. A total of 16 small-scale PCS and rebar reinforced column specimens were constructed and tested under monotonic\\u000a axial displacement. The experimental results indicate that the overall behavior of rebar and PCS reinforced specimens are\\u000a comparable prior to achieving the peak column load.
Surfactant enhanced remediation of soil columns contaminated by residual tetrachloroethylene
K. D. Pennell; M. Jin; L. M. Abriola; G. A. Pope
The ability of aqueous surfactant solutions to recover tetrachloroethylene (PCE) entrapped in Ottawa sand was evaluated in four column experiments. Residual PCE was emplaced by injecting (14)C-labeled PCE into water-saturated soil columns and displacing the free product with water. Miscible displacement experiments were conducted before and after PCE entrapment to determine the influence or residual PCE on column dispersivities. The
Ozone and Oxygen Absorption in Downflow Bobble Columns
P. Herbrechtsmeier; H. Schõfer; R. Steiner
During the development of the downflow bubble column, knowledge of the specific interfacial area was a precondition for assessing the mass transfer performance. A comparison with other gas\\/liquid contactors shows that, in the downflow bubble column, higher mass transfer areas can be obtained than, for example, in a bottom-sparged bubble column or in a loop-type reactor in the region of
Modelling of rectangular RC columns strengthened with FRP
M Maalej; S Tanwongsval; P Paramasivam
Existing analytical models for predicting the stress¢strain or load¢displacement response of fibre-reinforced polymer (FRP)-confined concrete are mostly derived for cylindrical plain concrete columns. In practice, however, typical concrete columns come in various shapes including circular, square, or rectangular and incorporate longitudinal and transverse steel reinforcements. Furthermore, strengthening or repairing is typically done while the column is under service loading. In
In-plant testing of microbubble column flotation
Luttrell, G.H.; Mankosa, M.J.; Adel, G.T.; Yoon, R.H.
This report describes progress in two areas: advanced instrumentation and column installation. The project is working with both 30-inch and 8-foot columns for coal flotation. The paper describes installation of the instrument package, the control loops, and the data acquisition system. Under the second area of study, a test plan was developed for a parametric study of the 8-foot column operating conditions (feed flow rate, gas flow rate, wash water flow rate, and froth addition) that were determined to influence separation efficiency on the 30-inch column. Results to date are discussed. 7 refs., 4 tabs. (CK)
Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey
15. FIRST FLOOR WAREHOUSE SPACE, SHOWING COLUMN / BEAM CONNECTION. VIEW TO SOUTHWEST. - Commercial & Industrial Buildings, Dubuque Seed Company Warehouse, 169-171 Iowa Street, Dubuque, Dubuque County, IA
Stability of leaning column at Devils Tower National Monument, Wyoming
Harp, Edwin L.; Lindsay, Charles R.
In response to reports from climbers that an 8-meter section (referred to as the leaning column) of the most popular climbing route on Devils Tower in northeastern Wyoming is now moving when being climbed, scientists from the U.S. Geological Survey inspected the site to determine the stability of the column and the underlying column that serves as a support pedestal. Evidence of a recent tensile spalling failure was observed on the pedestal surface immediately beneath the contact with the overlying leaning column. The spalling of a flake-shaped piece of the pedestal, probably due to the high stress concentration exerted by the weight of the leaning column along a linear contact with the pedestal, is likely causing the present movement of the leaning column. Although it is unlikely that climbers will dislodge the leaning column by their weight alone, the possibility exists that additional spalling failures may occur from the pedestal surface and further reduce the stability of the leaning column and result in its toppling. To facilitate detection of further spalling failures from the pedestal, its surface has been coated with a layer of paint. Any new failures from the pedestal could result in the leaning column toppling onto the climbing route or onto the section of the Tower trail below.
Attosecond pulse characterization.
Laurent, G; Cao, W; Ben-Itzhak, I; Cocke, C L
In this work we propose a novel procedure for the characterization of attosecond pulses. The method relies on the conversion of the attosecond pulse into electron wave-packets through photoionization of atoms in the presence of a weak IR field. It allows for the unique determination of the spectral phase making up the pulses by accurately taking into account the atomic physics of the photoionization process. The phases are evaluated by optimizing the fit of a perturbation theory calculation to the experimental result. The method has been called iPROOF (improved Phase Retrieval by Omega Oscillation Filtering) as it bears a similarity to the PROOF technique [Chini et al. Opt. Express 18, 13006 (2010)]. The procedure has been demonstrated for the characterization of an attosecond pulse train composed of odd and even harmonics. We observe a large phase shift between consecutive odd and even harmonics. The resulting attosecond pulse train has a complex structure not resembling a single attosecond pulse once per IR period, which is the case for zero phase. Finally, the retrieval procedure can be applied to the characterization of single attosecond pulses as well. PMID:23938540
Analysis of flurbiprofen, ketoprofen and etodolac enantiomers by pre-column derivatization RP-HPLC and application to drug¢protein binding in human plasma
Yin-Xiu Jin; Yi-Hong Tang; Su Zeng
A stereoselective reversed-phase high-performance liquid chromatography (HPLC) assay to determine the enantiomers of flurbiprofen, ketoprofen and etodolac in human plasma was developed. Chiral drug enantiomers were extracted from human plasma with liquid¢liquid extraction. Then flurbiprofen and ketoprofen enantiomers reacted with the acylation reagent thionyl chloride and pre-column chiral derivatization reagent (S)-(?)-?-(1-naphthyl)ethylamine (S-NEA), and etodolac enantiomers reacted with S-NEA using 1-(3-dimethylaminopropyl)-3-ethyl-carbodiimide
Determination of cocaine and benzoylecgonine by direct injection of human urine into a column-switching liquid chromatography system with diode-array detection
M. R. Brunetto; Y. Delgado Cayama; L. Gutiķrrez GarcĒa; M. Gallignani; M. A. Obando
A method for the determination of cocaine (COC) and benzoylecgonine (BZE) in human urine using a column-switching liquid chromatography system is reported. A homemade precolumn (20mmū4.6mm i.d.) dry-packed with Alltech ODS-C18 (35¢750?m) was employed as an extraction precolumn in order to extract and concentrate the COC and BZE from the human urine sample. The analytes were continuously transferred to the
Liquid chromatography with ultraviolet detection of lasalocid, monensin, salinomycin and narasin in poultry feeds using pre-column derivatization
Guglielmo Dusi; Valentina Gamba
A rapid and very effective analytical procedure for the simultaneous determination of four polyether antibiotics (PEs) lasalocid, monensin, salinomycin and narasin in poultry feeds was tested. PEs were extracted from samples using methanol and without any clean-up derivatized with 2,4-dinitrophenylhydrazine (DNP) in an acidic medium at 55░C. The derivatization mixture was analyzed directly on an ODS column (150ū4.6 mm, 5?m)
Preliminary Study of High Resolution HPLC Analytical Method for Sedimentary Pigments Based on Coupled C8 Columns
NASA Astrophysics Data System (ADS)
Yao, P.; Yu, Z.; Deng, C.; Liu, S.; Zhao, J.
The pigments in marine water columns can provide accurate estimates of community composition and abundance of phytoplankton. In addition, the sedimentary pigments, especially the derivatives of chlorophyll such as pyrophaeophytins, pyrophaeophorbides and steryl chlorin esters (SCEs) formed during early diagenesis can also provide information on the primary producer community and the changes in paleoproductivity. Accordingly, analysis of pigments and their derivatives is of great importance for oceanography, limnology and geochemistry. Many methods have been developed for the separation of chlorophylls, carotenoids and their derivatives derived from phytoplankton and water column samples using high-performance liquid chromatography (HPLC). Methods widely cited in the literatures include those developed by Wright et al. (1991) and Zapata et al. (2000). Both methods use reversed-phase columns, but C18 column was employed in Wright et al. (1991) and C8 column in Zapata et al. (2000). However, evident coelutions are observed in published works. This will particularly cause problematic identification and quantification in dealing with sedimentary pigments which are highly complex and often display a broad range in polarity. Clearly, it is necessary to improve the separation of the complex pigments if the information carried by the pigments is to be used fully. Coupled C18 columns were used in the HPLC method developed by Airs et al. (2001) for the analysis of complex pigment distributions. Improved chromatographic resolution, more pigment components and novel bacteriochlorophyll derivatives were obtained by this method. It indicates a new road for HPLC method development. C8 column has shorter carbon chains than that of C18 column and can provide less retention of apolar compounds which is of particular advantaged to hydrophobic chlorophyll a, b and their derivatives. That is one of the reasons why the C8 method developed by Zapata et al. (2000) is admittedly better than C18 method when analyze phytoplankton and water samples. Here we present an improved HPLC method based on coupled C8 columns and the method of Zapata et al. (2000). The flow rate and elution gradient of Zapata et al. (2000) method was adjusted, and the pigment extracts of surface sediment from different sites such as the Yangtze River Estuary, North Yellow Sea and the Xiangxi River in Three Gorges Reservoir,China were analyzed using the novel method. More pigments identified, improved resolution and LCMS applicability reveal the potential of the coupled C8 columns method for analyzing complex pigment distributions in sediments.(Funded by Natural Science Foundation of China (40676068, 40476044))
Separation, Preconcentration and Speciation of Metal Ions by Solid Phase Extraction
This review presents the most recent applications of solid phase extraction for the separation, preconcentration and speciation of metals, metalloids, and organometals. The review focuses on solid phase, column treatments and on the applications of this technique to various samples. This review also intends to discuss some applications and limitations associated to solid phase extraction techniques due to the necessity
Pulse MagnetPulse MagnetPulse MagnetPulse MagnetPulse Magnet DAQ SoftwareDAQ SoftwareDAQ SoftwareDAQ SoftwareDAQ Software
Pulse MagnetPulse MagnetPulse MagnetPulse MagnetPulse Magnet DAQ SoftwareDAQ SoftwareDAQ SoftwareDAQ SoftwareDAQ Software User ManualUser ManualUser ManualUser ManualUser Manual #12;Main Pulse Magnet DAQ be saved over an existing file. MAIN PULSE MAGNET DAQ SCREEN: 1 #12;RECALL SETTINGS Use this button
Cullen, Raymond Paul
. Richard t&. Badges A millimeter-diameter pulsed-coil system has been developed which will permit Zeeman spectroscopy at a modest cost. A high power pulse generator which delivers 170 amperes into a 0. 5 ohm load is the energy source for the coil. A... out that miniature coil pulsed systems can produce the same high magnetic fields using storage systems of only one or two joules capacity and possess in addition many advantages because of the small coil size. The Zeeman effect in ruby and other...
Microfluidic chip for peptide analysis with an integrated HPLC column, sample enrichment column, and nanoelectrospray tip.
Yin, Hongfeng; Killeen, Kevin; Brennen, Reid; Sobek, Dan; Werlich, Mark; van de Goor, Tom
Current nano-LC/MS systems require the use of an enrichment column, a separation column, a nanospray tip, and the fittings needed to connect these parts together. In this paper, we present a microfabricated approach to nano-LC, which integrates these components on a single LC chip, eliminating the need for conventional LC connections. The chip was fabricated by laminating polyimide films with laser-ablated channels, ports, and frit structures. The enrichment and separation columns were packed using conventional reversed-phase chromatography particles. A face-seal rotary valve provided a means for switching between sample loading and separation configurations with minimum dead and delay volumes while allowing high-pressure operation. The LC chip and valve assembly were mounted within a custom electrospray source on an ion-trap mass spectrometer. The overall system performance was demonstrated through reversed-phase gradient separations of tryptic protein digests at flow rates between 100 and 400 nL/min. Microfluidic integration of the nano-LC components enabled separations with subfemtomole detection sensitivity, minimal carryover, and robust and stable electrospray throughout the LC solvent gradient. PMID:15649049
Evaluation of capillary gas chromatography for pesticide and industrial chemical residue analysis. II. Comparison of quantitative results obtained on capillary and packed columns.
Fehringer, N V; Walters, S M
Results of pesticide and industrial chemical residue determinations, using both capillary and packed column gas chromatography (GC), in 3 Food and Drug Administration (FDA) laboratories have been compiled and compared. Samples consisted of food products collected for routine residue screening by the respective laboratories. Extracts were prepared by conventional multiresidue methodology. Capillary column systems and operating conditions were selected at the discretion of each laboratory and were therefore variable, although split/splitless injectors in the split mode were used with prescribed precautions in all cases. Packed column systems were operated as specified in the FDA Pesticide Analytical Manual (PAM). Overall correlation between the 2 systems, expressed as the average ratio of packed column result to capillary column result, was 0.99 for 120 determinations in 41 samples. The higher resolving power of the capillary systems allowed quantitation of several residues that were incompletely separated and therefore unquantifiable using the packed columns. Capillary column GC with the split injection technique, used with appropriate precautions, was found to be both reliable and advantageous for regulatory determination of pesticide and industrial chemical residues in foods and feeds. PMID:3949710
Pulse measurement apparatus and method
Marciante, John R. (Webster, NY); Donaldson, William R. (Pittsford, NY); Roides, Richard G. (Scottsville, NY)
An embodiment of the invention is directed to a pulse measuring system that measures a characteristic of an input pulse under test, particularly the pulse shape of a single-shot, nano-second duration, high shape-contrast optical or electrical pulse. An exemplary system includes a multi-stage, passive pulse replicator, wherein each successive stage introduces a fixed time delay to the input pulse under test, a repetitively-gated electronic sampling apparatus that acquires the pulse train including an entire waveform of each replica pulse, a processor that temporally aligns the replicated pulses, and an averager that temporally averages the replicated pulses to generate the pulse shape of the pulse under test. An embodiment of the invention is directed to a method for measuring an optical or an electrical pulse shape. The method includes the steps of passively replicating the pulse under test with a known time delay, temporally stacking the pulses, and temporally averaging the stacked pulses. An embodiment of the invention is directed to a method for increasing the dynamic range of a pulse measurement by a repetitively-gated electronic sampling device having a rated dynamic range capability, beyond the rated dynamic range of the sampling device; e.g., enhancing the dynamic range of an oscilloscope. The embodied technique can improve the SNR from about 300:1 to 1000:1. A dynamic range enhancement of four to seven bits may be achieved.
New type of pulse current sensors for on-line partial discharge monitoring
Fang Qiongl; Xu Yang; Coa Xiaolong; Geng Fenghui; Ding Rui; Lu Gang
Pulse current sensors are widely used to extract partial discharge (PD) signals from transformers for on-line PD measurement, and excellent pulse current sensors can help the measuring system to enhance the anti-interference ability for on-line monitoring. Authors did experiments on three kinds of current sensors with their inner diameter 450 mm in order to detect pulse signals of transformer bushings.
Pulse stretching in a Q-switched Nd:YAG laser
NASA Astrophysics Data System (ADS)
Schmid, W. E.
Stretching of Q-switched Nd:YAG laser pulses has been achieved by rapidly varying the resonator output coupling during the pulse duration, using Pockels cell driven by a high-voltage planar triode. An analytical solution for the temporal variation of loss, inversion, and photon density has been found. Flat laser pulses up to 600 ns duration and energy extraction efficiency close to 100 percent have been demonstrated experimentally.
Pulse-Burst Laser Systems for Thomson Scattering on MST
NASA Astrophysics Data System (ADS)
den Hartog, D. J.; Borchardt, M. T.; Harris, W. S.; Reusch, J. A.; Yang, Y. M.
A new purpose-built ``pulse-burst'' laser system is being constructed for the Thomson scattering diagnostic on the MST reversed-field pinch. This new laser will produce a burst of 1--2 J Q-switched pulses at repetition rates 5--250 kHz. It will operate at 1064 nm and is a master oscillator, power amplifier (MOPA) system. Variable pulse-width drive (0.15--20 ms) of the flashlamps in this laser will be accomplished by IGBT switching of large electrolytic capacitor banks. A subset of these power supplies has already been constructed and is currently being used to drive the flashlamps in the two existing commercial Nd:YAG lasers used for Thomson scattering on MST. Each of these upgraded lasers now produces a burst of up to fifteen 2 J Q-switched pulses (1064 nm) at repetition rates 1--12.5 kHz. Direct control of the laser Pockels cell drive enables optimal pulse energy extraction, and up to four 2 J laser pulses during one flashlamp pulse. These lasers are currently being used to study the dynamic evolution of electron temperature in MST. The new purpose-built ``pulse-burst'' laser system will further expand this capability.
Potential antitermite compounds from Juniperus procera extracts.
Kinyanjui, T; Gitu, P M; Kamau, G N
Thin layer chromatography (TLC) analysis revealed that destructive distillation of Juniperus procera tree gave ten major components, whereas Croton megalocarpus tree yielded five components. This was confirmed by gas chromatography (GC). The components were isolated by column chromatography and analysed using infrared, ultra-violet, visible and mass spectroscopy (MS) techniques. The whole extract was about 30.3% of the starting material (sawdust) and consisted of 77.5% water and 22.5% oily reddish-brown layer. The extracts had alcoholic and phenolic compounds together with acids. Cedrol, a tertiary tricyclic alcohol, was found to be in the greatest proportion in the oily layer. IR spectra with a peak beyond 3000 cm(-1), UV-VIS absorption maxima at 230 nm and mass spectra with m/e 204 suggested the presence of cedrene in the extract. PMID:10879825
Size Exclusion HPLC of Protein Using a Narrow-Bore Column for Evaluation of Bread-Making Quality of Hard Spring Wheat Flours
Technology Transfer Automated Retrieval System (TEKTRAN)
The objective of this study was to investigate if a narrow-bore column (NBC) (300 x 4.5 mm i.d.) improved analyses of unreduced proteins in flour by size exclusion HPLC (SE-HPLC) and subsequent evaluation of bread-making quality of hard spring wheat flours. Total protein extracts and sodium dodecyl...
X-ray pulsar models. II. Comptonized spectra and pulse shapes
Meszaros, P.; Nagel, W.
We calculate pulse shapes and spectra for various X-ray pulsar models, including simple self-emitting or externally illuminated slabs and columns. We use a discrete-ordinate transfer scheme with eight angles x 32 frequencies x 2 polarizations and ignore bulk motions and inhomogeneities. With these simplifications, the calculated pulse shapes, cyclotron profiles, and continua as a function of phase angle are compared against observations. This indicates that slab models are in better general agreement with observations than column models. The injection of soft photons at h..omega../sub s/< or approx. =1 keV seems required to explain the power law continuum. The possibility of determining the cyclotron energy by means of the pulse shapes is discussed.
Tissue- and column-specific measurements from multi-parameter mapping of the human cervical spinal cord at 3 T.
Samson, R S; Ciccarelli, O; Kachramanoglou, C; Brightman, L; Lutti, A; Thomas, D L; Weiskopf, N; Wheeler-Kingshott, C A M
The aim of this study was to quantify a range of MR parameters [apparent proton density, longitudinal relaxation time T1, magnetisation transfer (MT) ratio, MT saturation (which represents the additional percentage MT saturation of the longitudinal magnetisation caused by a single MT pulse) and apparent transverse relaxation rate R2*] in the white matter columns and grey matter of the healthy cervical spinal cord. The cervical cords of 13 healthy volunteers were scanned at 3 T using a protocol optimised for multi-parameter mapping. Intra-subject co-registration was performed using linear registration, and tissue- and column-specific parameter values were calculated. Cervical cord parameter values measured from levels C1-C5 in 13 subjects are: apparent proton density, 4822 ▒ 718 a.u.; MT ratio, 40.4 ▒ 1.53 p.u.; MT saturation, 1.40 ▒ 0.12 p.u.; T1 = 1848 ▒ 143 ms; R2* = 22.6 ▒ 1.53 s(-1). Inter-subject coefficients of variation were low in both the cervical cord and tissue- and column-specific measurements, illustrating the potential of this method for the investigation of changes in these parameters caused by pathology. In summary, an optimised cervical cord multi-parameter mapping protocol was developed, enabling tissue- and column-specific measurements to be made. This technique has the potential to provide insight into the pathological processes occurring in the cervical cord affected by neurological disorders. PMID:24105923
Mook, H.A. Jr.
In one aspect, the invention is an improved pulsed-neutron monochromator of the vibrated-crystal type. The monochromator is designed to provide neutron pulses which are characterized both by short duration and high density. A row of neutron-reflecting crystals is disposed in a neutron beam to reflect neutrons onto a common target. The crystals in the row define progressively larger neutron-scattering angles and are vibrated sequentially in descending order with respect to the size of their scattering angles, thus generating neutron pulses which arrive simultaneously at the target. Transducers are coupled to one end of the crystals to vibrate them in an essentially non-resonant mode. The transducers propagate transverse waves in the crystal which progress longitudinally therein. The waves are absorbed at the undriven ends of the crystals by damping material mounted thereon. In another aspect, the invention is a method for generating neutron pulses characterized by high intensity and short duration.
Mook, Jr., Herbert A. (Oak Ridge, TN)
In one aspect, the invention is an improved pulsed-neutron monochromator of the vibrated-crystal type. The monochromator is designed to provide neutron pulses which are characterized both by short duration and high density. A row of neutron-reflecting crystals is disposed in a neutron beam to reflect neutrons onto a common target. The crystals in the row define progressively larger neutron-scattering angles and are vibrated sequentially in descending order with respect to the size of their scattering angles, thus generating neutron pulses which arrive simultaneously at the target. Transducers are coupled to one end of the crystals to vibrate them in an essentially non-resonant mode. The transducers propagate transverse waves in the crystal which progress longitudinally therein. The wave are absorbed at the undriven ends of the crystals by damping material mounted thereon. In another aspect, the invention is a method for generating neutron pulses characterized by high intensity and short duration.
NSDL National Science Digital Library
WGBH Boston
In this health activity, learners create a device so that they not only feel their heartbeat, but also see it, using a straw and some clay. Learners calculate their pulse rate (beats per minute) while at rest and after exercise.
McCormick, Martin (Martin Steven)
This thesis develops an exact approach for processing pulse signals from an integrate-and-fire system directly in the time-domain. Processing is deterministic and built from simple asynchronous finite-state machines that ...
NASA Technical Reports Server (NTRS)
Myers, Roger M. (inventor); Rawlin, Vinvent K. (inventor)
A cathode in an MPD thruster has an internal heater and utilizes low work function material. The cathode is preheated to operating temperature, and then the thruster is fired by discharging a capacitor bank in a pulse forming network.
Christiansen, D.W.; Brown, W.F.
A welder is described for automated closure of fuel pins by a pulsed magnetic process in which the open end of a length of cladding is positioned within a complementary tube surrounded by a pulsed magnetic welder. Seals are provided at each end of the tube, which can be evacuated or can receive tag gas for direct introduction to the cladding interior. Loading of magnetic rings and end caps is accomplished automatically in conjunction with the welding steps carried out within the tube.
Fluid dynamic parameters in bubble columns with internals
Jinwen Chen; Fan Li; Sujatha Degaleesan; Puneet Gupta; Muthanna H. Al-Dahhan; Milorad P. Dudukovic; Bernard A. Toseland
The knowledge of gas holdup, liquid recirculation and turbulent parameters is important for design and performance calculation of bubble column reactors. Although numerous experimental studies have been reported on this subject, most are point measurements limited to columns without internals operated at low gas velocities. In this study, we present the results obtained for the gas holdup profiles, time-averaged liquid
Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey
45. GROUND FLOOR OF 1852 WING LOOKING WEST. COLUMNS IN RIGHT FOREGROUND ORIENTED 90 TO NEW WING; COLUMNS IN BACKGROUND ORIENTED 90 TO EARLIER 1814-16-43 WING. - Boston Manufacturing Company, 144-190 Moody Street, Waltham, Middlesex County, MA
A Better Method for Filling Pasteur Pipet Chromatography Columns
ERIC Educational Resources Information Center
Ruekberg, Ben
An alternative method for the preparation of Pasteur pipet chromatography columns is presented that allows the column to be filled with solvent without bubbles and allows greater control of fluid flow while the materials to be separated are added. Students are required to wear gloves and goggles and caution should be used while handling glassģ
A laboratory experiment was designed to increase the understanding of the geoelectric effects of microbial " degradation of hydrocarbons. Eight large columns were were paired to provide a replicate of each of four experiments. These large-volume columns contained "sterilized" soi...
Devising an adjustable splitter for dual-column gas chromatography
Chieh-Heng Wang; Chih-Chung Chang; Jia-Lin Wang
A flow controlled adjustable splitter was configured from a Deans switch and employed in an automated dual column gas chromatographic (GC) system for analyzing mono-aromatic compounds. Volatile organic compounds (VOCs), thermally desorbed from the sorbent trap, were split by the adjustable splitter onto two columns of different phases for separation and then detection by flame ionization detection (FID). Unlike regular
A process-oriented regression model for column ozone
I. Wohltmann; R. Lehmann; M. Rex; D. Brunner; J. A. Mõder
Multiple regression models for time series of ozone column measurements have been a standard tool of atmospheric sciences for decades. We propose a new model, which is based on a process-oriented approach and captures all major processes relevant to the change of stratospheric ozone column. These are assumed to be short- and long-term changes by tropospheric and stratospheric pressure systems,
Dimensions and dynamics of co-ignimbrite eruption columns
Andrew W. Woods; Kenneth Wohletz
A model of the coignimbrite volcanic eruption column process is presented, and it is shown that the coignimbrite columns associated with the eruptions of Toba 75,000 yr ago and Tambora in 1815 may have ascended only about 32 and 23 km. This corroborates arguments that the mass of sulfuric acid aerosols injected into the statosphere and not the eruptive power
The Book Review Column1 by William Gasarch
Gasarch, William Ian
, in decreasing order of price. Welcome to the Book Reviews Column. We hope to bring you at least two reviewsThe Book Review Column1 by William Gasarch Department of Computer Science University of Maryland: the website www.bestbookbuys.com will, given a book, list LOTS of websites that are selling that book
Fire behaviour of concrete filled elliptical steel columns
Ana Espinos; Leroy Gardner; Manuel L. Romero; Antonio Hospitaler
In this work, a non-linear three-dimensional finite element model is presented in order to study the behaviour of axially loaded concrete filled elliptical hollow section (CFEHS) columns exposed to fire. This study builds on previous work carried out by the authors on concrete filled circular hollow section (CFCHS) columns both at room temperature and in fire. The numerical model is
The Book Review Column1 by William Gasarch
Gasarch, William Ian
The Book Review Column1 by William Gasarch Department of Computer Science University of Maryland at College Park College Park, MD, 20742 email: firstname.lastname@example.com Editorial about Book Prices: In the first draft of this column I had the following comment about Beck's book on Combinatorial Games: The books
VLDB 2009 Tutorial Column-Oriented Database Systems
VLDB 2009 Tutorial Column-Oriented Database Systems 1 Re-use permitted when acknowledging: Stavros Harizopoulos (HP Labs) Part 2: Daniel Abadi (Yale) Part 3: Peter Boncz (CWI) VLDB 2009 Tutorial #12;VLDB 2009 Tutorial Column-Oriented Database Systems 2 Re-use permitted when acknowledging
Exploring the Sulfur Nutrient Cycle Using the Winogradsky Column
ERIC Educational Resources Information Center
Rogan, Brian; Lemke, Michael; Levandowsky, Michael; Gorrell, Thomas
The Winogradsky column demonstrates how the metabolic diversity of prokaryotes transforms sulfur to different forms with varying redox states and hence, supplies nutrients and/or energy to the organism. The Winogardsky column is an excellent way to show that not all bacteria are pathogens and they have an important role in the geochemical cyclingģ
Stabilization of Regional Column Models by Parameterized Dynamical Tendencies
J. W. Bergman
Atmospheric Single Column Models (SCMs) provide an efficient modeling framework for regional studies. In these models, vertical profiles of temperature and humidity evolve in response to diabatic interactions within the column and adiabatic tendencies produced by by the large scale circulation. The adiabatic tendencies are either prescribed or neglected and,thus, decoupled from the diabatic tendencies. This decoupling can lead to
Taxicab Correspondence Analysis of Contingency Tables with One Heavyweight Column
ERIC Educational Resources Information Center
Choulakian, V.
The aim of this paper is to study the analysis of contingency tables with one heavyweight column or one heavyweight entry by taxicab correspondence analysis (TCA). Given that the mathematics of TCA is simpler than the mathematics of correspondence analysis (CA), the influence of one heavyweight column on the outputs of TCA is studied explicitlyģ
RC column strengthening by lateral pre-tensioning of FRP
Ali A. Mortazavi; Kypros Pilakoutas; Ki Sang Son
This paper presents a unique strengthening technique for existing concrete columns that use expansive materials to apply lateral pre-tensioning. The technique increases the capacity and ductility of a column as well as achieving better utilisation of the confining FRP (Fibre Reinforced Polymer) material. The confinement material properties and the confined cylinder performance are investigated experimentally. From the results, it is
Structural performance of rotationally restrained steel columns in fire
Faris Ali; David OÆConnor
The paper represents the outcomes of a parametric experimental investigation on the performance of rotationally restrained steel columns in fire. This experimental programme is a part of major research project performed at the Fire Research Center, University of Ulster in collaboration with the University of Sheffield. As a part of steel frames, half scale steel columns were tested in fire
Column dampers with negative stiffness: high damping at small amplitude
Lakes, Roderic
! 1! Column dampers with negative stiffness: high damping at small amplitude adapted from Kalathur, H., Lakes, R. S., Column dampers with negative stiffness: high damping at small amplitude, Smart negative; the moduli become complex to allow viscoelastic behavior. As modulus is tuned, damping
S. Lee; W. King
Models have been developed to simulate the thermal characteristics of Crystalline Silicotitanate (CST) ion exchange media fully loaded with radioactive cesium in a column configuration and distributed within a waste storage tank. This work was conducted to support the Small Column Ion Exchange (SCIX) program which is focused on processing dissolved, high-sodium salt waste for the removal of specific radionuclides
M. A. LANGTHJEM; Y. Sugiyama
This paper offers a survey of simple, flexible structural elements subjected to non-conservative follower loads, such as those caused by the thrust of rocket- and jet engines, and by dry friction in automotive disk- and drum-brake systems. Emphasis is on the ōcanonical problemsö, Beck's, Reut's, Leipholz's, and Hauger's columns. Beck's and Reut's columns have been realized experimentally, and very good
The ability of aqueous surfactant solutions to recover tetrachloroethylene (PCE) entrapped in Ottawa sand was evaluated in four column experiments. Residual PCE was emplaced by injecting 14C-labeled PCE into water-saturated soil columns and displacing the free product ...
The ability of aqueous surfactant solutions to recover tetrachloroethylene (PCE) entrapped in Ottawa and was evaluated in four column experiments. esidual PCE was emplaced by injecting 14 C-labeled PCE into water-saturated soil columns and displacing the free product with water. ...
Superradiant pulse compression using free-carrier plasma
G. Shvets; N. J. Fisch; A. Pukhov; J. Meyer-ter-Vehn
Free-carrier plasma can be used as an effective nonlinear medium for pulse compression. In the backward Raman amplifier geometry, the lower-frequency seed can extract most of the long pump energy through the mechanism of nonlinear superradiance. Filamentation is avoided due to strong dependence of the Raman instability growth rate on the wavenumber.
NASA Astrophysics Data System (ADS)
Johnson, Mark A.; Cote, Paul J.
There is need to replace hazardous radioluminescent light sources with a means of illumination that is environmentally friendly. This paper describes an electronic source that was developed as a potential candidate to replace low intensity tritium in a military system. It employs an LED for illumination and a 3-volt coin cell battery as a power source. This new light source is electronically invisible, requires minimal maintenance, and provides the lowest practical illumination to preclude detection by optical means. The low intensity requires that the LED be driven at DC current levels resulting in poor luminous efficiency. Therefore, in an effort to maximize battery life, the LED is pulsed into a more optically efficient mode of operation. However, conventional pulsing techniques are not employed because of concerns the electronics could be identified by conspicuous power spectral density (PSD) components in the electromagnetic spectrum generated by a pulsed LED. Therefore, flicker noise concepts have been employed to efficiently drive the LED while generating a virtually undetectable spectral signature. Although ideally the pulse durations, magnitudes, and spacings should be random, a significant reduction in conspicuous PSD components can be achieved when imposing practical constraints. The dominant components of the power spectrum are significantly reduced using fixed pulse durations and magnitudes while varying only the pulse spacing. The mean duty cycle is set to provide the same effective illumination as DC operation while generating a PSD normally associated with natural phenomena.
Luttkus, A K; Dudenhausen, J W
Within the last ten years several groups adapted pulse oximetry to be used in the fetus. The obvious advantage of this technology is the fact that a biochemical parameter--the arterial oxygen saturation--can be measured continuously during delivery. Nevertheless, the continuous information about the fetal oxygenation during delivery has a couple of obstacles to surmount. It is well known that fetal reflectance pulse oximetry may be influenced by a number of artifacts. In addition, severe physiological considerations should remind us of the limited diagnostic value of saturation monitoring alone in order to predict fetal acidosis. Some recent articles deal with the predictive value of fetal pulse oximetry for fetal compromise. While it appears that the fetal wellbeing is more likely to be in accordance with a normal saturation measured by current pulse oximetry systems, the number of fetuses detected by pulse oximetry suffering from hypoxia seems to be low. Different authors describe a poor sensitivity to predict fetal compromise. One reason therefore may be the reduced precision of the oxysensor in the low saturation range. Therefore, we conclude that the current generation of fetal pulse oximetry sensors is not improving the quality of combined fetal monitoring of fetal heart rate and fetal scalp blood analysis. PMID:9866017
Mourad, Jean-Jacques
A WELL IDENTIFIED RISK FACTOR: Other than systolic, diastolic and mean pressure, arterial pulse pressure (or differential pressure) is an independent factor of cardiovascular and notably coronary risk. The role of this factor is now clearly quantified in untreated hypertensive patients, but also in treated apparently controlled patients, and in patients with normal blood pressure. Demonstration of the deleterious role of an increase in pulse pressure was also made in populations at high risk of events such as heart failure, post-infarction or in hemodialyzed patients. FROM A THERAPEUTIC POINT OF VIEW: Antihypertensive treatments have inconstant efficacy on pulse pressure and new therapeutic routes appear promising. However, in the absence of available proof that a strategy axed on the decrease in pulse pressure improves cardiovascular prognosis, current recommendations do not yet include pulse pressure levels in therapeutic strategies. AN EFFICIENT MARKER: Whilst awaiting further data, the measurement of pulse pressure, because of its pertinence and simplicity, provides the practitioner with one of the most efficient markers for screening persons at high risk of cardiovascular and particularly coronary risk. PMID:12378979
Lee, S
In support of a small column ion exchange (SCIX) process for the Savannah River Site waste processing program, transient and steady state two-dimensional heat transfer models have been constructed for columns loaded with cesium-saturated crystalline silicotitanate (CST) or spherical Resorcinol-Formaldehyde (RF) beads and 6 molar sodium tank waste supernate. Radiolytic decay of sorbed cesium results in heat generation within the columns. The models consider conductive heat transfer only with no convective cooling and no process flow within the columns (assumed column geometry: 27.375 in ID with a 6.625 in OD center-line cooling pipe). Heat transfer at the column walls was assumed to occur by natural convection cooling with 35 C air. A number of modeling calculations were performed using this computational heat transfer approach. Minimal additional calculations were also conducted to predict temperature increases expected for salt solution processed through columns of various heights at the slowest expected operational flow rate of 5 gpm. Results for the bounding model with no process flow and no active cooling indicate that the time required to reach the boiling point of {approx}130 C for a CST-salt solution mixture containing 257 Ci/liter of Cs-137 heat source (maximum expected loading for SCIX applications) at 35 C initial temperature is about 6 days. Modeling results for a column actively cooled with external wall jackets and the internal coolant pipe (inlet coolant water temperature: 25 C) indicate that the CST column can be maintained non-boiling under these conditions indefinitely. The results also show that the maximum temperature of an RF-salt solution column containing 133 Ci/liter of Cs-137 (maximum expected loading) will never reach boiling under any conditions (maximum predicted temperature without cooling: 88 C). The results indicate that a 6-in cooling pipe at the center of the column provides the most effective cooling mechanism for reducing the maximum temperature with either ion exchange material. Sensitivity calculations for the RF resin porosity, the ambient external column temperature, and the cooling system configuration were performed under the baseline conditions to assess the impact of these parameters on the maximum temperatures. It is noted that the cooling mechanism at the column boundary (forced versus natural convection) and the cooling system configuration significantly impact the maximum temperatures. The analysis results provide quantitative information associated with process temperature control requirements and management of the SCIX column.
Simple pulse asynchronous state machines
Jeffrey Miller; Woodward Yang
Pulse computation is a hybrid of conventional analog and digital techniques which encodes and processes information in the time domain. In this paper we present a new technique for pulse computation with simple pulse-driven, asynchronous finite state machines. Asynchronous FSMs are robust and timescale-independent, and can be used as building blocks for constructing complex pulse processors. The notion of state
Low power consuming pulse detector
P. Rulikowski; V. Sokol; J. Barrett
A new approach for detection of ultra-wideband pulses based on a flip-flop circuit is proposed in this paper. A functional sample of the pulse detector was designed, manufactured and measured. The detector is able to detect a pulse 335 ps wide with a pulse repetition frequency (PRF) of at least 10 MHz, whereas a minimum detectable signal level is approximately
Results of interlaboratory comparisons of column percolation tests.
Kalbe, Ute; Berger, Wolfgang; Simon, Franz-Georg; Eckardt, J³rgen; Christoph, Gabriele
Laboratory leaching tests may be used for source term determination as a basis for risk assessment for soil-groundwater pathway (leachate forecast) on contaminated sites in Germany. Interlaboratory comparisons on the evaluation of the reproducibility of column percolation tests were conducted within the framework of an integrated R+D program using three waste reference materials. The interlaboratory comparisons of column percolation tests showed good reproducibility of the results for inorganic and organic parameters as well as for the accompanying parameters. This is due to the stipulations concerning the time of contact between leachant and sample material as well as the sample placement in the columns. Different column dimensions used by the participants of the interlaboratory comparisons did not have any substantial influence on the column test results. PMID:17451876
In-plant testing of microbubble column flotation
Luttrell, G.H.; Mankosa, M.J.; Adel, G.T.; Yoon, R.H.
Testing of micro-bubble column flotation continued. Work during this time frame was concentrated on completion of the automated control and data acquisition system and the factorial test plan for evaluating the performance of the 8-foot column (Tasks 2.5 and 3.3). Preliminary results obtained from the factorial test program indicate that higher frother addition and aeration rates result in a higher separation efficiency. Furthermore, an increase in collector dosage results in higher column yields under most conditions. The Allen-Bradley PLC has been installed and program development completed for control of the 8-foot column. A completely automated start-up and shut-down sequence has been developed. This sequence can be initiated by the operator from a plant floor industrial interface. Instrumentation of the 30-inch column has also been completed. Testing of this instrumentation is currently underway. 11 figs., 5 tabs.
Void fraction measurements in bubble columns using computed tomography
Kumar, S.B.; Dudukovic, M.P. [Washington Univ., St. Louis, MO (United States); Moslemian, D. [Florida Atlantic Univ., Boca Raton, FL (United States). Dept. of Mechanical Engineering
A Computed Tomographic (CT) scanner has been developed for imaging void fraction distributions in two phase flow systems such as bubble columns and fluidized beds. The scanner has been used to study the effects of various operating parameters such as column diameter, superficial gas velocity, distributor type, etc. on the void fraction and its distribution in an air-water bubble column. The results of this experimental investigation are presented and discussed. It was found that the column dimensions have no significant effect on the void fraction when the column diameter is greater than 0.15 m. Differences in the holdup distribution due to the kind of distributor used are significant only at low gas flow rates. Surface tension of the liquid has a profound influence on the void fraction and its distribution.
Experimental study of wave propagation dynamics of multicomponent distillation columns
Ting, J.; Helfferich, F.G.; Hwang, Y.L.; Graham, G.K.; Keller, G.E. II
Distillation columns with sharp separations exhibit severely nonlinear behavior, which has been known to cause difficulties in column control and design. Such a column is characterized by sharp composition and temperature variations in the column. Previously, the binary distillation case was thoroughly analyzed using a nonlinear wave theory and such an analysis was experimentally validated. For multicomponent distillation, the complicated nonlinear dynamics of the movement and interference of multiple sharp composition variations can be elucidated with a coherent-wave theory developed earlier for general countercurrent separation processes. With a ternary alcohol mixture, the present study has experimentally verified the theory by demonstrating the existence and propagation of constant-pattern coherent waves in a 50-tray stripping column in response to a step disturbance of feed composition, feed flow rate, or reboiler heat supply. The study has also tested the theory's predictions of composition profile, wave velocities, and asymmetric dynamics.
Experimental study of wave propagation dynamics of binary distillation columns
Hwang, Y.L.; Graham, G.K.; Keller, G.E. II [Union Carbide Corp., South Charleston, WV (United States)] [Union Carbide Corp., South Charleston, WV (United States); Ting, J.; Helfferich, F.G. [Pennsylvania State Univ., University Park, PA (United States). Dept. of Chemical Engineering] [Pennsylvania State Univ., University Park, PA (United States). Dept. of Chemical Engineering
High-purity distillation columns are typically difficult to control because of their severely nonlinear behavior reflected by their sharp composition and temperature profiles. The dynamic behavior of such a column, as characterized by the movement of its sharp profile, was elucidated by a nonlinear wave theory established previously. With binary alcohol mixtures, this study provides an experimental observation of such wave-propagation dynamics of a 40-tray stripping column and a 50-tray fractionation column in response to step disturbances of feed composition, feed flow rate, and reboiler heat supply. These experimental results have verified that the sharp profile in a high-purity column moves as a constant-pattern wave and that the nonlinear wave theory predicts its velocity satisfactorily with very simple mathematics. Results also demonstrate the asymmetric dynamics of the transitions between two steady states.
Electrically heated, air-cooled thermal modulator and at-column heating for comprehensive two-dimensional gas chromatography.
Libardoni, Mark; Waite, J Hunter; Sacks, Richard
An instrument for comprehensive two-dimensional gas chromatography (GCxGC) is described using an electrically heated and air-cooled thermal modulator requiring no cryogenic materials or compressed gas for modulator operation. In addition, at-column heating is used to eliminate the need for a convection oven and to greatly reduce the power requirements for column heating. The single-stage modulator is heated by current pulses from a dc power supply and cooled by a conventional two-stage refrigeration unit. The refrigeration unit, together with a heat exchanger and a recirculating pump, cools the modulator to about -30 degrees C. The modulator tube is silica-lined stainless steel with an internal film of dimethylpolysiloxane. The modulator tube is 0.18 mm i.d. x 8 cm in length. The modulator produces an injection plug width as small as 15 ms. PMID:15859594
Production of an extended plasma column in vacuum by irradiating a target by a quasi-Bessel beam
Batenin, V M; Bychkov, S S; Margolin, L Ya; Pyatnitskii, Lev N; Tal'virskii, A D; Fomenko, E V [Scientific Association for High Temperatures, Russian Academy of Sciences, Moscow (Russian Federation)
A technique of focusing the heating radiation was investigated, which makes it possible to produce an extended (under laboratory conditions, up to 1 m and over) plasma column and enables an easy output of VUV radiation. A plane solid-state target in vacuum was arranged along the caustic of a conic lens (axicon), which focused the laser beam. An analytic dependence, which describes the spatial intensity distribution of the heating radiation in the case of a nontransparent, partially reflecting target, was derived and experimentally verified. Experiments on the irradiation of an aluminium target in vacuum with a 5-J, 5-ns pulse of a neodymium-glass laser were performed. A plasma column up to 30 mm in length and no greater than 10 {mu}m in diameter was formed. A rather intense plasma radiation was recorded in the VUV range. (interaction of laser radiation with matter. laser plasma)
Design and construction of the 3.2 MeV high voltage column for DARHT II
Peters, C., Elliott, B.; Yu, S.; Eylon, S.; Henestroza, E.
A 3.2 MeV injector has been designed and built for the DARHT II Project at Los Alamos Lab. The installation of the complete injector system is nearing completion at this time. The requirements for the injector are to produce a 3.2 MeV, 2000-ampere electron pulse with a flattop width of at least 2-microseconds and emittance of less than 0.15 pi cm-rad normalized. A large high voltage column has been built and installed. The column is vertically oriented, is 4.4 meters long, 1.2 meters in diameter, and weighs 5700 kilograms. A novel method of construction has been employed which utilizes bonded Mycalex insulating rings. This paper will describe the design, construction, and testing completed during construction. Mechanical aspects of the design will be emphasized.
Extraction and speciation of arsenic in lacustrine sediments
Ficklin, W.H.
Arsenic was partially extracted with 4.OM hydrochloric acid, from samples collected at 25-cm intervals in a 350-cm column of sediment at Milltown Reservoir, Montana and from a 60-cm core of sediment collected at the Cheyenne River Embayment of Lake Oahe, South Dakota. The sediment in both reservoirs is highly contaminated with arsenic. The extracted arsenic was separated into As(III) and As(V) on acetate form Dowex 1-X8 ion-exchange resin with 0.12M HCl eluent. Residual arsenic was sequentially extracted with KClO3 and HCl. Arsenic was determined by graphite-furnace atomic-absorption spectrometry. The analytical results define oxidized and reduced zones in the sediment columns. ?? 1990.
Assessment of provitamin A determination by open column chromatography/visible absorption spectrophotometry.
Rodriguez-Amaya, D B; Kimura, M; Godoy, H T; Arima, H K
Determination of provitamin A content by open column chromatography/visible absorption spectrophotometry is assessed using food samples of varying carotenoid composition. A general method consisting of extraction with acetone, transfer to petroleum ether, saponification (optional), concentration, separation on activated MgO:Hyflo Supercel column developed with 1 to 15% acetone in petroleum ether, and quantitation of individual provitamins spectrophotometrically demonstrates repeatability comparable with that of high-performance liquid chromatographic (HPLC) methods. Overnight saponification (10% methanolic KOH, ambient temperature) does not degrade the provitamins and is unnecessary for kale, tomato, and squash; however, it is required for good separation of papaya carotenoids due to the presence of carotenol esters. The current Association of Official Analytical Chemists (AOAC) method is found to be inappropriate because (1) the volume of extracting solvent is not adjusted to the type of sample; (2) the less active alpha- and gamma-carotene, alpha- and beta-cryptoxanthin, and 5,6-monoepoxy-beta-cryptoxanthin (50% active) are quantified as beta-carotene (100% active); (3) inactive carotenoids such as xi-carotene and zeinoxanthin are also quantified as beta-carotene. PMID:3230117
Pulse shaping with transmission lines
Wilcox, R.B.
A method and apparatus for forming shaped voltage pulses uses passive reflection from a transmission line with nonuniform impedance. The impedance of the reflecting line varies with length in accordance with the desired pulse shape. A high voltage input pulse is transmitted to the reflecting line. A reflected pulse is produced having the desired shape and is transmitted by pulse removal means to a load. Light activated photoconductive switches made of silicon can be utilized. The pulse shaper can be used to drive a Pockels cell to produce shaped optical pulses.
Pulse shaping with transmission lines
Wilcox, Russell B. (Oakland, CA)
A method and apparatus for forming shaped voltage pulses uses passive reflection from a transmission line with nonuniform impedance. The impedance of the reflecting line varies with length in accordance with the desired pulse shape. A high voltage input pulse is transmitted to the reflecting line. A reflected pulse is produced having the desired shape and is transmitted by pulse removal means to a load. Light activated photoconductive switches made of silicon can be utilized. The pulse shaper can be used to drive a Pockels cell to produce shaped optical pulses.
Pulse shaping with transmission lines
NASA Astrophysics Data System (ADS)
Wilcox, R. B.
A method and apparatus for forming shaped voltage pulses uses passive reflection from a transmission line with nonuniform impedance. The impedance of the reflecting line varies with length in accordance with the desired pulse shape. A high voltage input pulse is transmitted to the reflecting line. A reflected pulse is produced having the desired shape and is transmitted by pulse removal means to a load. Light activated photoconductive switches made of silicon can be utilized. The pulse shaper can be used to drive a Pockels cell to produce shaped optical pulses.
Efficient optical pulse stacker system
Seppala, Lynn G. (Pleasanton, CA); Haas, Roger A. (Pleasanton, CA)
Method and apparatus for spreading and angle-encoding each pulse of a multiplicity of small area, short pulses into several temporally staggered pulses by use of appropriate beam splitters, with the optical elements being arranged so that each staggered pulse is contiguous with one or two other such pulses, and the entire sequence of stacked pulses comprising a single, continuous long pulse. The single long pulse is expanded in area, and then doubly passed through a nonstorage laser amplifier such as KrF. After amplification, the physically separated, angle-encoded and temporally staggered pulses are recombined into a single pulse of short duration. This high intensity output beam is well collimated and may be propagated over long distance, or used for irradiating inertial confinement fusion targets.
Photoconductive circuit element pulse generator
Rauscher, Christen (Alexandria, VA)
A pulse generator for characterizing semiconductor devices at millimeter wavelength frequencies where a photoconductive circuit element (PCE) is biased by a direct current voltage source and produces short electrical pulses when excited into conductance by short laser light pulses. The electrical pulses are electronically conditioned to improve the frequency related amplitude characteristics of the pulses which thereafter propagate along a transmission line to a device under test.
Contact pulsed Nd:YAG ablation of human dentin: ablation rates and tissue effects
NASA Astrophysics Data System (ADS)
Harris, David M.; Yessik, Michael J.
Dentin from freshly extracted human teeth was exposed to flashlamp pumped Nd:YAG pulses (100 microsecond(s) duration, 50 - 200 mJ/pulse) delivered through a flat cut fiberoptic in contact with the dentin surface. Ablation depth and volume were measured optically and confirmed with electron microscope morphometrics. Ablation depth increased with force applied at the fiber tip up to 5 - 10 g. Above this ablation depths were insensitive to applied force. Craters made in dental stone were deeper and narrower than those made in normal dentin. Ablation depths per pulse and volumes per pulse decrease as the number of pulses increase. This is more prominent for 200 mJ pulses. At 60 mJ the ablation depths are the same from 10 to 100 Hz repetition rates, although qualitative changes (collateral damage) are greater at higher repetition rates. A progressive increase in collateral damage is seen from the 1st through the 200th pulse.
Column Grid Array Rework for High Reliability
NASA Technical Reports Server (NTRS)
Mehta, Atul C.; Bodie, Charles C.
Due to requirements for reduced size and weight, use of grid array packages in space applications has become common place. To meet the requirement of high reliability and high number of I/Os, ceramic column grid array packages (CCGA) were selected for major electronic components used in next MARS Rover mission (specifically high density Field Programmable Gate Arrays). ABSTRACT The probability of removal and replacement of these devices on the actual flight printed wiring board assemblies is deemed to be very high because of last minute discoveries in final test which will dictate changes in the firmware. The questions and challenges presented to the manufacturing organizations engaged in the production of high reliability electronic assemblies are, Is the reliability of the PWBA adversely affected by rework (removal and replacement) of the CGA package? and How many times can we rework the same board without destroying a pad or degrading the lifetime of the assembly? To answer these questions, the most complex printed wiring board assembly used by the project was chosen to be used as the test vehicle, the PWB was modified to provide a daisy chain pattern, and a number of bare PWB s were acquired to this modified design. Non-functional 624 pin CGA packages with internal daisy chained matching the pattern on the PWB were procured. The combination of the modified PWB and the daisy chained packages enables continuity measurements of every soldered contact during subsequent testing and thermal cycling. Several test vehicles boards were assembled, reworked and then thermal cycled to assess the reliability of the solder joints and board material including pads and traces near the CGA. The details of rework process and results of thermal cycling are presented in this paper.
Novel techniques for slurry bubble column hydrodynamics
Dudukovic, M.P.
The objective of this cooperative research effort between Washington University, Ohio State University and Exxon Research Engineering Company was to improve the knowledge base for scale-up and operation of slurry bubble column reactors for syngas conversion and other coal conversion processes by increased reliance on experimentally verified hydrodynamic models. During the first year (July 1, 1995--June 30, 1996) of this three year program novel experimental tools (computer aided radioactive particle tracking (CARPT), particle image velocimetry (PIV), heat probe, optical fiber probe and gamma ray tomography) were developed and tuned for measurement of pertinent hydrodynamic quantities, such as velocity field, holdup distribution, heat transfer and bubble size. The accomplishments were delineated in the First Technical Annual Report. The second year (July, 1996--June 30, 1997) was spent on further development and tuning of the novel experimental tools (e.g., development of Monte Carlo calibration for CARPT, optical probe development), building up the hydrodynamic data base using these tools and comparison of the two techniques (PIV and CARPT) for determination of liquid velocities. A phenomenological model for gas and liquid backmixing was also developed. All accomplishments were summarized in the Second Annual Technical Report. During the third and final year of the program (July 1, 1997--June 30, 1998) and during the nine months no cost extension, the high pressure facility was completed and a set of data was taken at high pressure conditions. Both PIV, CT and CARPT were used. More fundamental hydrodynamic modeling was also undertaken and model predictions were compared to data. The accomplishments for this period are summarized in this report.
Simple, selective, and rapid quantification of 1-deoxynojirimycin in mulberry leaf products by high-performance anion-exchange chromatography with pulsed amperometric detection.
Yoshihashi, Tadashi; Do, Huong Thi Thu; Tungtrakul, Patcharee; Boonbumrung, Sumitra; Yamaki, Kohji
1-Deoxynojirimycin (DNJ) occurs in mulberry and other plants and is a highly potent glycosidase inhibitor reported to suppress blood glucose levels, thus preventing diabetes. Derivatization is required for quantification of DNJ upon use of spectral detection methods. Because of this difficulty, the DNJ contents of mulberry-based food products are rarely stated, even if DNJ is their active component. A simple, selective, and rapid method of high-performance anion-exchange chromatography with pulsed amperometric detection (HPAEC-PAD) to quantify DNJ in mulberry-based food products was developed. Stability testing of DNJ under heat treatment was also performed. A water extract of mulberry tea sample was subjected to HPAEC-PAD in a CarboPac MA1 column with a sodium hydroxide gradient. DNJ was clearly separated at a retention time of 7.26 min without interference and was selectively detected in the water extract. The detection limit was 5 ng. Heat stability studies suggested that DNJ was heat stable. HPAEC-PAD was not subject to interference, was highly selective for DNJ, and was superior to other high-performance liquid chromatography (HPLC) techniques in terms of sample preparation, resolution, and sensitivity. The method allowed simple, selective, and rapid analysis of DNJ in food matrices and might be useful for development of mulberry-based food products. Heat treatment could be an option for sterilizing mulberry-based products. PMID:20492274
Proton extraction from transition metals using PLATONE
NASA Astrophysics Data System (ADS)
Velardi, L.; Delle Side, D.; KrÓsa, J.; Nassisi, V.
In this work we present a study on proton beams extraction from a plasma generated by pulsed laser ablation of titanium and tantalum disks. The device used was the PLATONE laser ion source operating at the LEAS Laboratory in Lecce, Italy. It is based on a KrF laser operating at low irradiance (109-1010 W/cm2) and ns pulse duration. The proton and ions emission was analyzed by the time-of-flight technique using a Faraday cup as ion collector and an electrostatic barrier to identify the particles. Studies on the produced protons and ions at different laser irradiance values were performed. The extracted beams showed high proton flux up to 1010 protons/cm2.
Direct extraction of coherent mode properties from imaging measurements in a linear plasma column
NASA Astrophysics Data System (ADS)
Light, Adam; Thakur, Saikat; Brandt, Christian; Sechrest, Yancey; Tynan, George; Munsat, Tobin
We present imaging measurements of coherent waves in the Controlled Shear Decorrelation Experiment (CSDX). CSDX is a well-characterized linear machine producing dense plasmas relevant to the tokamak edge (Te ~ 3 eV, ne ~1013 /cc). Visible light from ArII line emission is collected at high frame rates using an intensified digital camera. A cross-spectral phase technique allows direct visualization of dominant phase structures as a function of frequency, as well as identification of azimuthal asymmetries present in the system. Experimental dispersion estimates are constructed from imaging data alone. Drift-like waves are identified by comparison with theoretical dispersion curves, and a tentative match of a low-frequency spectral feature to Kelvin-Helmholtz-driven waves is presented. Imaging measurements are consistent with previous results, and provide non-invasive, single-shot measurements across the entire plasma cross-section. Relationships between imaging and electrostatic measurements are explored, including limitations of both techniques. We present imaging measurements of coherent waves in the Controlled Shear Decorrelation Experiment (CSDX). CSDX is a well-characterized linear machine producing dense plasmas relevant to the tokamak edge (Te ~ 3 eV, ne ~1013 /cc). Visible light from ArII line emission is collected at high frame rates using an intensified digital camera. A cross-spectral phase technique allows direct visualization of dominant phase structures as a function of frequency, as well as identification of azimuthal asymmetries present in the system. Experimental dispersion estimates are constructed from imaging data alone. Drift-like waves are identified by comparison with theoretical dispersion curves, and a tentative match of a low-frequency spectral feature to Kelvin-Helmholtz-driven waves is presented. Imaging measurements are consistent with previous results, and provide non-invasive, single-shot measurements across the entire plasma cross-section. Relationships between imaging and electrostatic measurements are explored, including limitations of both techniques. The authors acknowledge support from the Center for Momentum Transport and Flow Organization, funded by the U.S. Department of Energy.
Monte Carlo study on pulse response of underwater optical channel
NASA Astrophysics Data System (ADS)
Li, Jing; Ma, Yong; Zhou, Qunqun; Zhou, Bo; Wang, Hongyuan
Pulse response of the underwater wireless optical channel is significant for the analysis of channel capacity and error probability. Traditional vector radiative transfer theory (VRT) is not able to deal with the effect of receiving aperture. On the other hand, general water tank experiments cannot acquire an accurate pulse response due to the limited time resolution of the photo-electronic detector. We present a Monte Carlo simulation model to extract the time-domain pulse response undersea. In comparison with the VRT model, a more accurate pulse response for practical ocean communications could be achieved through statistical analysis of the received photons. The proposed model is more reasonable for the study of the underwater optical channel.
Tall fescue seed extraction and partial purification of ergot alkaloids
Ji, Huihua; Fannin, F.; Klotz, J.; Bush, Lowell
Many substances in the tall fescue/endophyte association (Schedonorus arundinaceus/Epichloļ coenophiala) have biological activity. Of these compounds only the ergot alkaloids are known to have significant mammalian toxicity and the predominant ergot alkaloids are ergovaline and ergovalinine. Because synthetically produced ergovaline is difficult to obtain, we developed a seed extraction and partial purification protocol for ergovaline/ergovalinine that provided a biologically active product. Tall fescue seed was ground and packed into several different sized columns for liquid extraction. Smaller particle size and increased extraction time increased efficiency of extraction. Our largest column was a 114 ū 52 ū 61 cm (W ū L ū D) stainless steel tub. Approximately 150 kg of seed could be extracted in this tub. The extraction was done with 80% ethanol. When the solvent front migrated to bottom of the column, flow was stopped and seed was allowed to steep for at least 48 h. Light was excluded from the solvent from the beginning of this step to the end of the purification process. Following elution, ethanol was removed from the eluate by evaporation at room temperature and the resulting syrup was freeze-dried. About 80% recovery of alkaloids was achieved with 18-fold increase in concentration of ergovaline. Initial purification of the dried product was accomplished by extracting with hexane/water (6:1, v/v). The aqueous fraction was extracted with chloroform, the aqueous layer discarded, after which the chloroform was removed with a resulting 20-fold increase of ergovaline. About 65% of the ergovaline was recovered from the chloroform residue for an overall recovery of 50%. The resultant partially purified ergovaline had biological activities in in vivo and in vitro bovine bioassays that approximate that of synthetic ergovaline. PMID:25566528