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Most Cited Cryogenics Articles
The most cited articles published since 2011, extracted from Scopus.
Effect of cryogenic treatment on microstructure, mechanical and wear behaviors of AISI H13 hot work tool steelMahdi Koneshlou | Kaveh Meshinchi Asl | Farzad Khomamizadeh
Volume 51, Issue 1, January 2011, Pages 55-61
This paper focuses on the effects of low temperature (subzero) treatments on microstructure and mechanical properties of H13 hot work tool steel. Cryogenic treatment at -72 °C and deep cryogenic treatment at -196 °C were applied and it was found that by applying the subzero treatments, the retained austenite was transformed to martensite. As the temperature was decreased more retained austenite was transformed to martensite and it also led to smaller and more uniform martensite laths distributed in the microstructure. The deep cryogenic treatment also resulted in precipitation of more uniform and very fine carbide particles. The microstructural modification resulted in a significant improvement on the mechanical properties of the H13 tool steel. © 2010 Elsevier Ltd. All rights reserved.
Cryogenic turning of the Ti-6Al-4V alloy with modified cutting tool insertsM. Dhananchezian | M. Pradeep Kumar
Volume 51, Issue 1, January 2011, Pages 34-40
Productivity in the machining of titanium alloys is adversely affected by rapid tool wear as a consequence of high cutting zone temperature. Conventional cutting fluids are ineffective in controlling the cutting temperature in the cutting zone. In this research work, an attempt has been made to investigate the effect of liquid nitrogen when it is applied to the rake surface, and the main and auxiliary flank surfaces through holes made in the cutting tool insert during the turning of the Ti-6Al-4V alloy. The cryogenic results of the cutting temperature, cutting forces, surface roughness and tool wear of the modified cutting tool insert have been compared with those of wet machining. It has been observed that in the cryogenic cooling method, the cutting temperature was reduced by 61-66% and the surface roughness was reduced to a maximum of 36% over wet machining. The cutting force was decreased by 35-42% and the flank wear was reduced by 27-39% in cryogenic cooling over that of wet machining. Cryogenic cooling enabled a substantial reduction in the geometry of tool wear through the control of the tool wear mechanisms. The application of liquid nitrogen to the heat generation zones through holes made in the cutting tool insert was considered to be more effective over conventional machining. © 2010 Elsevier Ltd. All rights reserved.
Development of a three-dimensional finite-element model for high-temperature superconductors based on the H-formulationFrancesco Grilli | Roberto Brambilla | Frédéric Sirois | Antti Stenvall | Steeve Memiaghe
Volume 53, Issue , January 2013, Pages 142-147
Finite-element models are a powerful and widely used tool for evaluating the ac losses of HTS tapes and wires as well as of assemblies such as cables and coils. The H-formulation, which uses the magnetic field components as state variables, has proved to be an efficient implementation to solve 2-D problems, involving infinitely long or axially-symmetric geometries; an excellent agreement with experimental data has been found in many cases. However, the simulation of certain applications requires a full 3-D model. In this paper we report on the development of a 3-D model based on the H-formulation. We describe the implementation of Maxwell equations, the imposition of current constraints and we discuss the issues related to meshing 3-D volumes. The model is validated by comparing the results with those obtained with 2-D models in cases that can be investigated in 2-D; then, it is used to simulate cases that can be handled only in 3-D. © 2012 Elsevier Ltd. All rights reserved.
A review on heat exchanger thermal hydraulic models for cryogenic applicationsJulio Cesar Pacio | Carlos Alberto Dorao
Volume 51, Issue 7, July 2011, Pages 366-379
Heat exchangers are the main components in cryogenic processes. Thermo-economic considerations set the need for high-effectiveness equipment and accurate models. This situation is challenging due to the complex operating conditions and the fact that some physical effects, such as changes in fluid properties, flow maldistribution, axial conduction and heat leakage, cannot be neglected. In this work a systematic review of the state of art and challenges in modeling cryogenic heat exchangers is presented. They include lumped parameters, distributed parameters and stream-evolution models. These formulations fail to take all relevant effects into account. A general discussion on the performance of the reviewed models is presented. In general, more effects are included in the framework of numerical solution of discretized energy balance equation. Two main points stand out as not considered by the present models, namely the effects of pressure drop on heat transfer and the existence of partial flow mixing. These two effects are highly relevant for two-phase flow and multi-component applications, as in LNG processes. © 2011 Elsevier Ltd. All rights reserved.
An efficient multi-stage Brayton-JT cycle for liquefaction of natural gasHo Myung Chang | Myung Jin Chung | Sanggyu Lee | Kun Hyung Choe
Volume 51, Issue 6, June 2011, Pages 278-286
Combined multi-stage Brayton-JT refrigeration cycles are investigated as a governmental effort in Korea to develop an original liquefaction process of natural gas in accordance with recent demand of higher efficiency and larger capacity. Based upon thermodynamic optimization theory, a combined refrigeration system is proposed with nitrogen (N2) Brayton cycle, ethylene (C2) JT cycle, and propane (C3) JT cycles, which are used for cooling the feed gas in a series of heat exchangers. Since no mixed refrigerants are used, this system is simple in operation and robust in reliability. A complete cycle design is presented to confirm its feasibility and estimate the liquefaction performance. It is expected that the proposed N2-C2-C3 cycle could have a reasonably high efficiency and the potential of great liquefaction capacity. Next steps are underway for patent application and practical process development. © 2010 Elsevier Ltd. All rights reserved.
A sample-saving method for heat capacity measurements on powders using relaxation calorimetryEdgar Dachs | Artur Benisek
Volume 51, Issue 8, August 2011, Pages 460-464
An experimental method is described for determining the low-temperature heat capacity (Cp) of mg-sized powder samples using the Quantum Design "Physical Properties Measurement System" (PPMS). The powder is contained in an Al pan as an ∼1 mm thick compressed layer. The sample is not mixed with Apiezon N grease, as compared to other methods. Thus, it is not contaminated and can be used for further study. This is necessary for samples that are only available in tiny amounts. To demonstrate the method various samples, all insulating in nature, were studied including benzoic acid, sapphire and different silicate minerals. The measurements show that the method has an accuracy in Cp to better than 1% at T above 30-50 K and ±3-5% up to ±10% below. The experimental procedure is based on three independent PPMS and three independent differential scanning calorimetry (DSC) measurements. The DSC Cp data are used to slightly adjust the PPMS Cp data by a factor CpDSC/CpPPMSat298K. This is done because heat capacities measured with a DSC device are more accurate around ambient T (≤0.6%) than PPMS values and is possible because the deviation of PPMS heat capacities from reference values is nearly constant between about 50 K and 300 K. The resulting standard entropies agree with published reference values within 0.21% for the silicates, by 0.34% for corundum, and by 0.9% for powdered benzoic acid. The method thus allows entropy determinations on powders with an accuracy of better than 1%. The advantage of our method compared to other experimental techniques is that the sample powder is not contaminated with grease and that heat capacity values show less scatter at high temperatures. © 2011 Elsevier Ltd. All rights reserved.
Experimental investigations on cryogenic cooling by liquid nitrogen in the end milling of hardened steelS. Ravi | M. Pradeep Kumar
Volume 51, Issue 9, September 2011, Pages 509-515
Milling of hardened steel generates excessive heat during the chip formation process, which increases the temperature of cutting tool and accelerates tool wear. Application of conventional cutting fluid in milling process may not effectively control the heat generation also it has inherent health and environmental problems. To minimize health hazard and environmental problems caused by using conventional cutting fluid, a cryogenic cooling set up is developed to cool tool-chip interface using liquid nitrogen (LN 2). This paper presents results on the effect of LN 2 as a coolant on machinability of hardened AISI H13 tool steel for varying cutting speed in the range of 75-125 m/min during end milling with PVD TiAlN coated carbide inserts at a constant feed rate. The results show that machining with LN 2 lowers cutting temperature, tool flank wear, surface roughness and cutting forces as compared with dry and wet machining. With LN 2 cooling, it has been found that the cutting temperature was reduced by 57-60% and 37-42%; the tool flank wear was reduced by 29-34% and 10-12%; the surface roughness was decreased by 33-40% and 25-29% compared to dry and wet machining. The cutting forces also decreased moderately compared to dry and wet machining. This can be attributed to the fact that LN 2 machining provides better cooling and lubrication through substantial reduction in the cutting zone temperature. © 2011 Elsevier Ltd. All rights reserved.
A three-stage Stirling pulse tube cryocooler operating below the critical point of helium-4L. M. Qiu | Q. Cao | X. Q. Zhi | Z. H. Gan | Y. B. Yu | Y. Liu
Volume 51, Issue 10, October 2011, Pages 609-612
Precooled phase shifters can significantly enhance the phase shift effect and further improve the performance of pulse tube cryocoolers. A separate three-stage Stirling pulse tube cryocooler (SPTC) with a cold inertance tube was designed and fabricated. Helium-4 instead of the rare helium-3 was used as the working fluid. The cryocooler reached a bottom temperature of 4.97 K with a net cooling power of 25 mW at 6.0 K. The operating frequency was 29.9 Hz and the charging pressure was 0.91 MPa. It is the first time a refrigeration temperature below the critical point of helium-4 was obtained in a three-stage Stirling pulse tube cryocooler. © 2011 Elsevier Ltd. All rights reserved.
Investigations of pulsed heat loads on a forced flow supercritical helium loop - Part A: Experimental set upC. Hoa | M. Bon-Mardion | P. Bonnay | P. Charvin | J. N. Cheynel | B. Lagier | F. Michel | L. Monteiro | J. M. Poncet | P. Roussel | B. Rousset | R. Vallcorba-Carbonell
Volume 52, Issues 7-9, July 2012, Pages 340-348
Cryogenic systems for future large superconducting tokamaks are expected to handle high pulsed heat loads due to cycling plasma operation. The superconducting magnets are cooled down with forced flow supercritical helium at 4.4 K and 5 bar. Cryogenic helium distributions can participate to the smoothing of pulsed loads and hence providing a stable interface with the refrigerator. An experimental set up named HELIOS has been designed and realized in CEA Grenoble to study pulsed load effects on a forced flow supercritical helium loop. The characteristics of the main components and the instrumentation with its calibration during reception tests are described in Part A. A first series of experiments was performed with pulsed loads in an isochoric configuration: large pressure and temperature changes in the circulating loop are observed, analyzed and compared as well to a thermohydraulic modeling described in Part B. © 2012 Published by Elsevier Ltd. All rights reserved.
Effect of heat transfer on the performance of thermoelectric generator-driven thermoelectric refrigerator systemLingen Chen | Fankai Meng | Fengrui Sun
Volume 52, Issue 1, January 2012, Pages 58-65
A model of thermoelectric generator-driven thermoelectric refrigerator with external heat transfer is proposed. The performance of the combined thermoelectric refrigerator device obeying Newton's heat transfer law is analyzed using the combination of finite time thermodynamics and non-equilibrium thermodynamics. Two analytical formulae for cooling load vs. working electrical current, and the coefficient of performance (COP) vs. working electrical current, are derived. For a fixed total heat transfer surface area of four heat exchangers, the allocations of the heat transfer surface area among the four heat exchangers are optimized for maximizing the cooling load and the coefficient of performance (COP) of the combined thermoelectric refrigerator device. For a fixed total number of thermoelectric elements, the ratio of number of thermoelectric elements of the generator to the total number of thermoelectric elements is also optimized for maximizing both the cooling load and the COP of the combined thermoelectric refrigerator device. The influences of thermoelectric element allocation and heat transfer area allocation are analyzed by detailed numerical examples. Optimum working electrical current for maximum cooling load and COP at different total number of thermoelectric elements and different total heat transfer area are obtained, respectively. © 2011 Elsevier Ltd. All rights reserved.
Influence of working fluid on the performance of a standing-wave thermoacoustic prime moverX. H. Hao | Y. L. Ju | Upendra Behera | S. Kasthurirengan
Volume 51, Issue 9, September 2011, Pages 559-561
The thermoacoustic prime mover (TAPM) is an attractive alternative as a pressure wave generator to drive Pulse Tube Cryocoolers (PTCs), by the absence of moving parts, construction simplicity, reasonable efficiency, and environmental friendly. Decreasing the resonance frequency and improving the efficiency of the TAPM are important to drive the PTCs. These are controlled by the working gas parameters other than the dimensions of TAPM. In this technical note, the experimental studies carried out to evaluate the influence of different working fluids on the performances of a twin standing wave TAPM at various operating pressures have been compared with the simulation studies of the same system using DeltaEc wherever possible. The reasonably good agreement between them indicates the utility of DeltaEc for the optimal design of TAPM with the right working fluids for practical applications. © 2011 Elsevier Ltd. All rights reserved.
Influences of temperature and contact pressure on thermal contact resistance at interfaces at cryogenic temperaturesDongmei Bi | Huanxin Chen | Tian Ye
Volume 52, Issues 7-9, July 2012, Pages 403-409
The microscopic heat transfer between solid and solid at cryogenic temperatures exists in many application fields. This paper employed the Laser Photothermal Method (LPM) which is a transient and non-contact method to measure the Thermal Contact Resistance (TCR) between solid and solid in the temperature range of 70-290 K and the pressure range of 0.2-0.7 MPa. This paper analyzed the effects of the temperature and the contact pressure on the TCR at interfaces. The relationship between the TCR and the temperature at certain contact pressure was established, and the explanation about this phenomenon was given. Following, the TCR of SS 304-AlN, SS 304-Cu and SS 304-SS 304 were compared at different temperatures and contact pressures. © 2012 Published by Elsevier Ltd. All rights reserved.
Effect of multi-stream heat exchanger on performance of natural gas liquefaction with mixed refrigerantHo Myung Chang | Hye Su Lim | Kun Hyung Choe
Volume 52, Issue 12, December 2012, Pages 642-647
A thermodynamic study is carried out to investigate the effect of multi-stream heat exchanger on the performance of natural gas (NG) liquefaction with mixed refrigerant (MR). A cold stream (low-pressure MR) is in thermal contact with opposite flow of two hot streams (high-pressure MR and NG feed) at the same time. In typical process simulation with commercial software (such as Aspen HYSYS®), the liquefaction performance is estimated with a method of minimum temperature approach, simply assuming that two hot streams have the same temperature. In this study, local energy balance equations are rigorously solved with temperature-dependent properties of MR and NG feed, and are linked to the thermodynamic cycle analysis. The figure of merit (FOM) is quantitatively examined in terms of UA (the product of overall heat transfer coefficient and heat exchange area) between respective streams. In a single-stage MR process, it is concluded that the temperature profile from HYSYS is difficult to realize in practice, and the FOM value from HYSYS is an over-estimate, but can be closely achieved with a proper heat-exchanger design. It is also demonstrated that there exists a unique optimal ratio in three UA's, and no direct heat exchanger between hot streams is recommended. © 2012 Elsevier Ltd. All rights reserved.
Thermodynamics of active magnetic regenerators: Part iAndrew Rowe
Volume 52, Issues 2-3, February 2012, Pages 111-118
Cycle-averaged relationships for heat transfer, magnetic work, and temperature distribution are derived for an active magnetic regenerator cycle. A step-wise cycle is defined and a single equation describing the temperature as a function of time and position is derived. The main assumption is that the convective interaction between fluid and solid is large so that thermal equilibrium between fluid and solid exists during a fluid flow phase (regeneration). Relations for the temperatures at each step in the cycle are developed assuming small regenerative perturbations and used to derive the net cooling power and magnetic work at any location in the AMR. The overall energy balance expression is presented with transformations needed to relate the boundary conditions to effective operating temperatures. An expression is derived in terms of operating parameters and material properties when each location is regeneratively balanced; this relation indicates needed conditions so the local energy balance will satisfy the assumed cycle. By solving the energy balance expression to determine temperature distribution one can calculate work, heat transfer, and COP. © 2011 Elsevier Ltd. All rights reserved.
Magnetocaloric effect of (ErxR1-x)Co2 (R = Ho, Dy) for magnetic refrigeration between 20 and 80 KYiyin Zhu | Kai Asamoto | Yuta Nishimura | Takaaki Kouen | Satoshi Abe | Koichi Matsumoto | Takenori Numazawa
Volume 51, Issue 9, September 2011, Pages 494-498
Two series of RCo2 compounds, (ErxHo 1-x)Co2 and (EryDy1-y)Co 2, were investigated as magnetic refrigerants for hydrogen liquefaction. A large magnetocaloric effect (MCE) was observed just above the Curie temperature (Tc) of these compounds which both undergo a first-order magnetic transition. The isothermal entropy change ΔS and the adiabatic temperature change ΔTad of these compounds were larger than those of other Laves-phase materials such as RAl2 and RNi2. However, the temperature range of the large MCE for these compounds was limited. It has been shown that Tc increases almost linearly against the de Gennes factor, and can be controlled by changing the concentration of the rare earth elements while maintaining a first-order transition. By measuring the magnetization and heat capacity, we obtained temperature entropy (T-S) diagrams, which are essential for analyzing the magnetic refrigeration cycle. Both series of compounds showed high potential for use in a regenerative thermal cycle, especially as a combination of several compositions to cover a wide temperature range. © 2011 Elsevier Ltd. All rights reserved.
Optimization and analysis of mixed refrigerant composition for the PRICO natural gas liquefaction processXiongwen Xu | Jinping Liu | Le Cao
Volume 59, Issue , January 2014, Pages 60-69
In this paper, the energy optimization of the PRICO natural gas liquefaction (LNG) process was performed with the genetic algorithm (GA) and the process simulation software Aspen Plus. Then the characteristics of the heat transfer composite curves of the cold box were obtained and analyzed. Based on it, the heat exchange process in the cold box was divided into three regions. At last, in order to find the relationship between the energy consumption and the composition of the mixed refrigerant, the effects of the refrigerant flow composition on the temperature difference and the pinch point location were deeply investigated, which would be useful to guide the refrigerant charging. © 2013 Elsevier Ltd. All rights reserved.
Rational design of MgBDipak Patel | Md Shahriar Al Hossain | Ashkan Motaman | Shaon Barua | Mohammed Shahabuddin | Jung Ho Kim
2 conductors toward practical applications
Volume 63, Issue , January 2014, Pages 160-165
© 2014 Elsevier Ltd. All rights reserved.We report the research progress that has been made on developing rational MgB2 superconducting conductors toward practical applications. Owing to the poor performance of the critical current density (Jc) of bare MgB2, various techniques have been developed to overcome this obstacle. Among these, chemical doping has proved to be the most effective way to enhance the superconducting properties, such as Jc and the irreversibility field (Birr). More than a hundred different forms of dopants have been investigated over the past 13 years. Among these, the most effective dopants have been identified to be silicon carbide, carbon, and malic acid. The best results, Birr of 22 T and Jc of 40,000 A cm-2 at 4.2 K and 10 T, have been reported for malic acid treated MgB2 conductors, which have matched the benchmark performance of commercial low temperature superconductor wire such as Nb-Ti. This work will review and discuss the progress on MgB2 conductor development over the past few years at the University of Wollongong and Hyper Tech Research, Inc.
Computational fluid dynamics simulations of an orifice type pulse tube refrigerator: Effects of operating frequencyDion Savio Antao | Bakhtier Farouk
Volume 51, Issue 4, April 2011, Pages 192-201
A numerical study is reported here for the investigation of the fundamental flow and heat transfer processes found in an orifice type pulse tube refrigerator (OPTR). The OPTR is driven by a cyclically moving piston at one end of the system with helium as the working fluid. The regenerator and the various heat exchangers are modeled as porous media and a thermal non-equilibrium model is applied in these regions. The system is studied for different operating frequencies of the driver piston. The simulations reveal interesting steady-periodic flow patterns that develop in the pulse tube due to the fluctuations caused by the piston and the presence of the inertance tube. The predicted secondary-flow recirculation patterns in the pulse tube are found to affect the OPTR performance. When the secondary-flow patterns are well-developed, they help isolate the cold and hot ends of the pulse tube and create a thermal buffer zone at the center of the pulse tube, enhancing the performance of the OPTR. © 2011 Elsevier Ltd. All rights reserved.
Oil-field wastewater purification by magnetic separation technique using a novel magnetic nanoparticleZhuonan Liu | Huihui Yang | Hao Zhang | Chuanjun Huang | Laifeng Li
Volume 52, Issue 12, December 2012, Pages 699-703
In the present work, oil-field wastewater purification through superconducting magnetic separation technique using a novel magnetic nanoparticle was investigated. The magnetic nanoparticle, which has a multi-shell structure with ferroferric oxide as core, dense nonporous silica as inter layer and mesoporous silica as outer layer, was synthesized by co-precipitation method. To functionalize the magnetic nanoparticle, plasma polymerization technique was adopted and poly methyl acrylate (PMA) was formed on the surface of the nanoparticle. The multi-shell structure of the nanoparticle was confirmed by transmission electron microscope (TEM) and the characteristic is measurable by FTIR. It is found that most of the pollutants (85% by turbidity or 84% by COD value) in the oil-field wastewater are removed through the superconducting magnetic separation technique using this novel magnetic nanoparticle. © 2012 Elsevier Ltd. All rights reserved.
Overview of the recent performance of DI-BSCCO wireT. Nakashima | S. Kobayashi | T. Kagiyama | K. Yamazaki | M. Kikuchi | S. Yamade | K. Hayashi | K. Sato | G. Osabe | J. Fujikami
Volume 52, Issue 12, December 2012, Pages 713-718
Sumitomo Electric has been developing the silver-sheathed Bi2223 multi-filamentary wires since the discovery of Bi-based superconductors. DI-BSCCO (Dynamically-Innovative BSCCO) is the high performance wires produced with the controlled-overpressure (CT-OP) sintering technique. The recent R&D activities have enabled to produce the 1000 m-long wires with Ic of 200 A and the maximum Ic reached 250 A at 77 K by short sample. Besides, the fine control of the carrier density with the non-stoichiometric oxygen enhanced the in-field Ic performances at lower temperature. At a magnetic field of 3 T applied normal to wire surface, the Ic of 280 A at 30 K, and 420 A at 20 K were successfully achieved. To meet the growing needs for various high temperature superconducting applications, Type HT wire with high mechanical strength and Type G wire with low thermal conductivity have been developed. © 2012 Elsevier Ltd. All rights reserved.
Forced flow boiling heat transfer of liquid hydrogen for superconductor coolingYasuyuki Shirai | Hideki Tatsumoto | Masahiro Shiotsu | Koichi Hata | Hiroaki Kobayashi | Yoshihiro Naruo | Yoshifumi Inatani | Katsuhiro Kinoshita
Volume 51, Issue 6, June 2011, Pages 295-299
Heat transfer from inner side of a heated vertical pipe to liquid hydrogen flowing upward was first measured at the pressure of 0.7 MPa for wide ranges of flow rates and liquid temperatures. The heat transfer coefficients in non-boiling regime for each flow velocity were well in agreement with the Dittus-Boelter equation. The heat fluxes at the inception of boiling and the departure from nucleate boiling (DNB) heat fluxes are higher for higher flow velocity and subcooling. It was found that the trend of dependence of the DNB heat flux on flow velocity was expressed by the correlation derived by Hata et al. based on their data for subcooled flow boiling of water, although it has different propensity to subcooling. © 2010 Elsevier Ltd. All rights reserved.
Validation of the 4C code against data from the HELIOS loop at CEA GrenobleR. Zanino | R. Bonifetto | F. Casella | L. Savoldi Richard
Volume 53, Issue , January 2013, Pages 25-30
We complete the first validation campaign of the Cryogenic Circuit Conductor and Coil (4C) code, focusing on the cryogenic circuit module of 4C, which is based on the component models from the recently developed "Cryogenics" Modelica library. Measured data from the HELIOS facility (HElium Loop for hIgh LOads Smoothing) at CEA Grenoble, France, are used as reference. HELIOS includes a supercritical He loop (cold circulator, pipes equipped with resistive heaters, control and bypass valves, heat exchangers) and a saturated He bath. A repetitive heat pulse test is simulated with 4C. The computed evolution of temperature, pressure and mass flow rate at different circuit locations, both in the loop and in the bath, shows a very good agreement with the measurements. © 2012 Elsevier Ltd. All rights reserved.
Experimental study of a thermoacoustically-driven traveling wave thermoacoustic refrigeratorB. Yu | E. C. Luo | S. F. Li | W. Dai | Z. H. Wu
Volume 51, Issue 1, January 2011, Pages 49-54
New configurations of traveling wave thermoacoustic refrigerators driven by a traveling wave thermoacoustic engine were introduced and tested in this paper. First, the performance of the refrigerator with different-diameter inertance tubes was investigated experimentally. Then, investigation of substituting a flexible membrane attached to inertial mass for inertance tube was tested. The experimental results show that the substitution could improve the efficiency of the system and lead to a larger cooling power. So far, using helium gas as the working gas, the system could provide 340 W cooling power at the temperature of -20 °C with working frequency of 57 Hz and average pressure of 3.0 MPa. The total COP, i.e., cooling power divided by heating power, is 0.16. © 2010 Elsevier Ltd. All rights reserved.
An experimental study on flow patterns and heat transfer characteristics during cryogenic chilldown in a vertical pipeHong Hu | Jacob N. Chung | Samuel H. Amber
Volume 52, Issues 4-6, April 2012, Pages 268-277
In the present paper, the experimental results of a cryogenic chilldown process are reported. The physical phenomena involve unsteady two-phase vapor-liquid flow and intense boiling heat transfer of the cryogenic fluid that is coupled with the transient heat conduction inside pipe walls. The objective for the present study is to compare the chilldown rates and flow patterns between the upward flow and downward flow in a vertical pipe. Liquid nitrogen is employed as the working fluid and the test section is a vertical straight segment of a Pyrex glass pipe with an inner diameter of 8 mm. The effects of mass flow rate on the flow patterns, heat transfer characteristics and interface movement were determined through experiments performed under several different mass flow rates. Through flow visualization, measurement and analysis on the flow patterns and temperature variations, a physical explanation of the vertical chilldown is given. By observing the process and analyzing the results, it is concluded that pipe chilldown in a vertical flow is similar to that in microgravity to some extent. © 2012 Elsevier Ltd. All rights reserved.
Mechanical tests on the ITER PF 316L jacket after compactionH. J. Liu | Y. Wu | Q. Y. Han | Zh X. Wu | L. F. Li
Volume 51, Issue 6, June 2011, Pages 234-236
This paper focuses on mechanical tests on the ITER PF jacket 316L stainless steel material. As requirement of ITER, the conductor will be compacted after cable insertion. Young's modulus, yield strength (0.2% offset), ultimate tensile strength and elongation at failure shall be reported. For researching an effect of compaction on mechanical properties, the three jacket sections which were cut from the same jacket were compacted at 0%, 4.77% and 5.58% in cross section. The mechanical properties of materials were measured at 4.2 K, 77 K and 300 K. The effects of compaction on materials properties were discussed. TEM images showed that there were stress-induced martensite phase after compaction. It is concluded that the results are accordant with requirement of ITER. © 2010 Elsevier Ltd. All rights reserved.


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Google Apps Could Soon Not Work In Your Browser
Google said they would not be supporting Firefox 3.5, Internet Explorer 7, and Safari 3 or older browsers. "In these older browsers you may have trouble using certain features in Gmail, Google Calendar, Google Talk, Google Docs and Google Sites."
Yahoo Toolbar To Be Installed On HP Computers IE7 Browsers
The Associated Press reports that Yahoo and HP have struck a deal to have all desktop and laptop computers in the United ... read more
Daily SearchCast, May 12, 2006: Microsoft Pushes Back On Google IE7 Complaint; Yahoo's Semel Says Microsoft Has "No Chance" In Search & More!
Today's search podcast covers Microsoft pushing back on Google's Internet Explorer 7 favoritism complaints; Yahoo's Terry Semel Saying Microsoft has "no chance" ... read more
Daily SearchCast, May 10, 2006: Yahoo Livesearch: Answers Before You Finish Typing!; Yahoo & Google Seek IE7 Users; Will It Be Google Rather Than Vegemite Sandwich? & More! (Corrected File)
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Daily SearchCast, May 2, 2006: Google Double Standards On Microsoft's IE7 Search Plans; Amazon Dumps Google For Microsoft; Topographical Maps At Ask & More!
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Microsoft's IE 7 Serve Unfair Advantage Over Google & Yahoo?
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subset: commoncrawl


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|Women, Men, Girls
I am a snowboarding grandma who loves to knit. Warning: my patterns are unconventional!View all patterns by designer (7) »
I couldn't keep my eyes off Katniss in the beginning hunting scene of Hunger Games: Catching Fire. I did some research and discovered that the hunting vest she was wearing was woven. So I decided to created a knitted one. So cool!! I love it because I can wear it over a leather jacket like her or over anything I want. It's warm too, and easy to make
7 st. / 4 in
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iOS 4.3.1 now available
Apple just released iOS 4.3.1 to the world, aiming to fix things like iPod touch display issues, AV-out troubles, problems with enterprise apps, and a few other bugs that were hanging around. If you've been running iOS 4.3 and have been experiencing a few niggles, chances are this'll clear that up. Connect your iPhone, iPad, or iPod touch to iTunes and grab the update.
Apple may release iOS 4.3 today
Posted by Andru Edwards Categories: Apple, Cell Phones, Handhelds, Rumors, Software
Get ready to sync your iPhones, iPads, and iPods. Apple's iOS 4.3 is will reportedly launch today, according to Boy Genius Report.
At Apple's iPad 2 reveal last week, CEO Steve Jobs said iOS 4.3 would be available for download on March 11, the same day the updated iPad goes on sale. But according to BGR, Apple will release the newest version of its mobile operating system at around 1 p.m. EST today.
The update brings a variety of new features, including enhanced Safari performance, iTunes home sharing, AirPlay improvements, slider switch rotation, and a personal hotspot for the iPhone 4. Apple iOS 4.3 will support all iPads, third- and fourth-generation iPod touch, iPhone 4, and iPhone 3GS.
Click to continue reading Apple may release iOS 4.3 today
iOS 4.3 GM seed now available to developers
Apple has just made the final version of iOS 4.3 available to anyone with a developer account. You can grab the downloads for build 8F190 for iPhone 4 and 3GS, iPad, and iPod touch 3rd and 4th generation now. The iOS 4.3 SDK is also at GM status with build 10M2518, and you can grab that as well. All the rest of you, expect iOS 4.3 to launch alongside iPad 2 on March 11.
How Google can learn from the iPad 2
Apple's March 2 event is all but guaranteed to bring us the iPad 2, most likely with dual cameras and a revamped OS. It arrives two months after CES 2011, to a landscape littered with tablets from scores of manufacturers, most of them with one thing in common: they are running Google's Android OS. But only a handful of them run Android 3.0 (Honeycomb), the first Android tablet OS. Can tablets like the Motorola Xoom—the first Honeycomb device—take on the iPad?
If the past is any indicator, it doesn't look good. This has less to do with quality of product, however, and more to do with the manner in which the product is brought to the public.
The clear advantage Apple has over just about every competitor—except perhaps for RIM—is that it relies on no external manufacturers for its products. To clarify: of course Apple needs to farm out production of the components that make up its devices to OEMs, but when you see a new iPad, it is from Apple, running an Apple OS, for sale at the Apple store. The closest Apple comes to working with other companies is its partnerships with Verizon and AT&T for the iPhone and iPad. For the most part, however, Apple is its own, self-controlling entity. With no company—other than the carriers and OEMs— with which to coordinate, Apple can create a realistic product release timeline and stick to it.
Click to continue reading How Google can learn from the iPad 2
Apple confirms March 2 iPad 2 event
Posted by Andru Edwards Categories: Apple, Handhelds
Yesterday we posted with certainty that Apple would be announcing the iPad 2 on March 2, a week from today. Today, Apple has confirmed that date. As you can see, their invitation to their March 2 event features an iCal icon peeling away to reveal an iPad behind it. Doesn't get much clearer than that, does it? As always, we'll have the full details live as the event happens. Anyone else crossing their fingers for some iOS 5 news to share the stage next week?
Bleeding Edge TV 375: Looxcie wearable video recorder
Posted by Andru Edwards Categories: Gizmatic, Short Bytes, Accessories, Cameras, Features, Podcasts, Videocasts, Videos
If you've ever wanted to be able to capture a moment that you knew was coming, but weren't sure exactly when, you may want to check out Looxcie. It's a wearable video camera that constantly records. You can stream what you are recording live over the Internet, and if you wanna capture something, you just hit the button and it clips the last 30 seconds and saves it for you. If you have an iPhone or Android device, then you can even get an app that lets you use the phone as a viewfinder.
You can pick up Looxcie at Amazon.
Big thank you to JackThreads for sponsoring the show - be sure to check them out, we've got exclusive invite codes that give you $5 to use towards anything you'd like.
Apple finally details App Store subscriptions
Posted by Andru Edwards Categories: Apple, Corporate News
On Tuesday, Apple announced a subscription billing platform for the App Store, overcoming perhaps the biggest hurdle for the success of iPad periodicals.
The plan lets customers purchase subscriptions to iOS-supported newspapers, magazines, music, and other content in one click. Previously, customers had to manually purchase and download issues on an individual basis.
Publishers set their own price and lengths of subscriptions. Then, customers can click on the length of their desired subscriptions and automatically receive a charge to their iTunes accounts.
"We believe that this innovative subscription service will provide publishers with a brand new opportunity to expand digital access to their content onto the iPad, iPod touch and iPhone, delighting both new and existing subscribers," said Apple CEO Steve Jobs, who is currently on medical leave, in a statement.
Click to continue reading Apple finally details App Store subscriptions
Google Translate for iPhone review
Posted by Patrick Lambert Categories: Reference, Reviews, Google, Free Apps
Google Translate is one of the best known online translating service. It supports a large array of languages, and usually has very good results. The service has also been integrated in Android handsets for a while. Yesterday, Google released a native iPhone version as well. While there's been clones and unofficial apps before, this is the original, from Google itself. The app adds features over what the web has offered before, and is overall very impressive. It's no wonder that it shot right up in the top 10 apps on the App Store. Oh, and of course, it's completely free.
Read More | Google Translate for iPhone
Bleeding Edge TV 374: Intonow for iPhone is like Shazam for TV
Posted by Reza Malayeri Categories: Gizmatic, Short Bytes, Apple, Cell Phones, Features, Home Entertainment, Podcasts, Videocasts, Videos
IntoNow is a free app for the iPhone that allows you to connect with your friends around the shows you love. Simply place your iPhone in front of the TV, and IntoNow uses it's SoundPrint technology to recognize whatever you're watching. Once your show or movie is tagged, you can see how many other people are watching, share it with your friends, review it on IMDB, add it to your Netflix queue, and buy or rent it on iTunes.
IntoNow's SoundPrint technology covers more than 140 million minutes of previously aired shows, or the equivalent of 266 years of video. It can recognize a show even if it's airing live for the first time. SoundPrint has an index of "more than 2.6 million airings, indexed during the past five years, and it's growing by the second." They describe SoundPrint as a "fingerprinting" technology; a series of algorithms that can quickly identify a show based on the audio. They've has even made a SoundPrint API available for developers, so look for more applications to come out using SoundPrint technology.
Internet-connected social TV is becoming the new trend in technology, and data is showing that Americans are using TV and Internet together on an increasing basis. Google and Apple have launched their own internet connected set top boxes, and companies like Comcast and TiVo are major players as well. The future of social television looks very promising, and soon we'll all be "checking in" to our favorite TV shows on a regular basis, using awesome technology like IntoNow and SoundPrint, or other social apps like GetGlue.
Check out a demo of Intonow's social TV app in this episode.
How many times do you catch yourself watching tv while you're on the internet?
Big thank you to JackThreads for sponsoring the show - be sure to check them out, we've got exclusive invite codes that give you $5 to use towards anything you'd like.
iOS 4.3 beta 3 released to developers
iOS devs, time to get to downloading, as Apple has just released iOS 4.3 beta 3 alongside the iOS SDK 4.3. Downloads are available for the iPhone, iPad, iPod touch, and even the 2nd generation Apple TV. The SDK build is 10M2514, while the software for the devices is build 8F5166b. From the looks of things, this beta is all about checking and testing AirPlay video with the iOS devices and Apple TV. We will keep our eye out for any other new hotness in this build.
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text:
Hey all, I was curious as to what are the most annoying or hated baby names you have ever heard. This may help people narrow down the search for the perfect name. Sorry to offend anyone.
My top name I dislike is Navaeh!!!
alright! Neither of my boys names are on this list! LOL
I dislike Sydnee!!! or spelled Sydney.
Navy Wife, SAHM to Danica & Ariah ***www.mastokids.org***
Name: ayanna....it was pronounced R-E-anna...NO....aRianna is pronounced R-e-anna...Ayanna is pronounce Eye-anna...the little girl was a complete bitch about it...I am sure her parents did it so that she could hate the world and become a bully and hate all teachers...there was another Ayanna in the class with the correct pronunciation!!!!! her parents deserve to get punched in the face by everyone she comes across or until she smartens up and tells her parents they are idiots and fixes the spelling or changes the pronunciation!
Married to DH 8/13/05
DD born 6/13/09
DS born 10/31/10 - A Halloween baby!
Nevaeh is my least favorite too.
Llama llama single mama to a little shit apple.
Gold boobies.
Rhiannon pronounced Ray Ann. How the fuck is that Ray Ann?
Aiden, Cooper, Mason and Dillon are all way over used. However, some of us can't help that... my name is Sarah Elizabeth. How original is that? Mom picked it because no one was named Sarah. Then 1982-now happened.
Conner, Hampton.. All these last names being used as first names.. this does not make your kid rich you know.
Dakota.. only because one of the guys I work with's kid is a beast and needs duct taped to a wall, and that is his name.
Just have to say, I love that I haven't seen my LOs name on any name-related thread so far! No one else has said they picked it, and no one's said they hate it. Sweet.
I just read an article on why some countries have to approve a child's name; one couple just tried to name their child # (yes, pronounced hashmark!), another tried to do Adolf Hitler. Those aren't names, it's child abuse, lol
(09/07) (05/09) (02/09/13)


text:
It's time to put a bow on the 2012-13 NBA regular season as we dish out final grades to each impact rookie.
Five first-year stars earned marks in the "A" range. Who else besides Anthony Davis and Damian Lillard received strong grades?
For many rookies, the NBA season is a grueling marathon unlike anything they've experienced before. Some handle the ups and downs better than others.
Find out what everyone's report card looks like now that the dust has settled.
* "Impact Rookie" defined as a rookie who logged at least 17 minutes per game in 2012-13.


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