A method and apparatus performs the detection of an edge of a tape and further controls the read/write head to position itself relative to the detected edge. An array of photodetectors in an integrated circuit chip senses the intensity of light illuminating the chip with the tape running between the light source and the photodetectors. A light-to-dark transition is formed which is indicative of the edge of the tape.

The invention relates to a system for tracking the edge of a magnetic medium or an optical medium as well as tracking the data thereon.
In high speed magnetic tape reading and writing units ("tape streamers"), the data is read from, or written in, a plurality of data tracks which run parallel to the edges of a magnetic tape. The write/read head of the system must, therefore, be accurately positioned over a selected track to read the data from the selected track or to write new data in the track. It is known, for example, from U.S. Pat. No. 4,476,503 to position the write/read head by first locating an edge of the tape, and then moving the head a specified distance from the edge to the desired track, the tracks being disposed on the tape at respective known distances from the edge.
It is a problem in this technology, however, that in practice the tape will not travel in a constant, perfectly straight path. The tape in moving will meander slightly and will follow an irregular serpentine path. The position of the edge must be constantly monitored with high accuracy and the position of the head is constantly adjusted through a feedback system because data tracks are usually packed so closely together on the tape that a small change in the edge position, in the absence of a corresponding change in the position of the head, can cause the head to be adjacent a track other than the desired track.
Various tracking systems are known in the art for many purposes, such as a transducer which may be positioned relative to a recording tape edge in an optical system. A light transmitter, such as a point source illuminating both the tape and a photo sensor, may be partly covered by the tape and placed in a fixed position relative to the light source and the transducer. The diameter of the photo sensor must be greater than the expected transversal range of movement of the tape. A control system allows the transducer to follow the transversal displacements of the tape.
Another known alternative embodiment implements a fixed position light emitting bar as the light source, and a photo sensor which is rectangular and of the same length as the light emitting bar and fixed to the transducer itself. This embodiment allows for the positioning of a recording head or a transducer relative to the tape edge for a multi-track recording system. Each position requires one reference input to the position controller of the transducer. This allows a signal proportional to the position of the transducer relative to the edge of the tape to be used as an input for the controller, which thereafter sends an error signal proportional to the difference between the reference and the output of the photo sensor to a motor which controls the position of the transducer. There are, however, several drawbacks to such a system. In a first version of the system, the transducer is normally placed between two tape guides and the light beam must be placed between one guide and the transducer itself. The problem is that the drift direction at the position of the light beam and at the position of the transducer can be different. A second version of this system corrects this drift problem; however, since the output from the photosensor is an analog signal, the system is subject to additional problems. The most severe problem is its sensitivity to small dust particles. With a magnetic medium, such particles settle on the illuminated part of the photodiode, and it is difficult to detect the occurrence of and to compensate for such noise. Updating of the DC output from the photodiode each time the transducer is placed in a given position is not possible. In addition, the system is sensitive to stray light pickup unless synchronous detection is used. Similarly, stray light pickup is difficult to compensate for unless the tape drive is completely shielded from external light sources. The use of an infrared source may help, but the stray light pickup is still a problem since infrared light may as well be present as background noise. In a dynamic tracking system, stray light pickup normally contains 100 Hz or 120 Hz components which will disturb a tape edge tracking servo unless synchronous detection is used. If an infrared light source is used, the photodiode may need a filter which is translucent for the wavelength used. This causes the distance from the tape to the photodiode to be increased which in turn reduces the sharpness of the transition zone between the light and dark area of the detector.
Another known method has a magnetic tape passing over a fixed recording/reading head which is automatically balanced in a vertical direction. The nominal vertical position of the tape is determined by at least one set of photo sensors and light emitting diodes and arranged such that the tape edge(s) partially covers the photo sensor(s). A typical arrangement embodies two sets of sensors, one for the lower edge and one for the upper edge of the tape. In this embodiment, the head is adjusted and fixed in a position which corresponds to equal outputs from the two sensors when the tape is placed in its nominal position. A control signal is obtained by simply taking the difference between the outputs from the sensors. The error signal is fed to a motor in a mechanical arrangement capable of adjusting the position of the tape. Such a system is susceptible to the same type of errors as discussed in the above system.
Another embodiment contains two sets of light emitters and receivers very similar to the one described in the preceding paragraph. Problems typical with an analog proportional system, such as difficulties with adjusting and maintaining equal light levels in the two emitters and a circuit for manually balancing or trimming the AC light levels and automatically the DC levels, are still present. The system is inherently susceptible to differences which may occur after the factory adjustments of the light in the two channels; such manual adjustment increases both the production and the component cost of the product.
An automatic track following system is also known which uses at least two separate detecting heads with read gaps wider than the written tracks and where the gaps have azimuth angles of equal values but of opposite rotational sign. During tracking, the centers of the azimuth head follows the centers of the corresponding two signal tracks. When the tracks drift away from the center positions of the azimuth heads, a lead/lag error signal can be extracted from the two heads if the information signal tracks contain some type of known synchronization, e.g. if video sync pulses have been recorded in parallel on both tracks. The polarity of the lead/lag signal determines the direction to move the head, and its value is proportional to the error if the tracks are located within the range of the azimuth gaps. Since auxiliary read gaps are used, responding only to the video sync pulses of long wavelengths, the azimuth angle can be tolerated. The extra tape noise from the unrecorded data can be tolerated in the timing channels due to the lower bandwidth requirement. However, the primary disadvantage of such a system is the inherent weakness of using azimuth heads for tracking, since such allows for a very limited linear tracking range. If tracking is disturbed, the control system has no information available about the direction to move the head. Noise pulses may cause head movement in the wrong direction as well. The head must be moved to the nominal position before the tracking system can be activated after a loss of the lead/lag signal, or a track seeking algorithm must be activated to start recovery. Another disadvantage is the added cost of the extra read heads Such tracking systems are best suited for helical scan tape formats where the tracking can immediately lock on neighbor tracks if disturbed. Such a disturbance can be tolerated in some consumer analog video tape recorders (single frame loss or disturbance) or in helical scan data storage systems where interleaved data frames and error correction permits the loss of a track.
Another known embodiment proposes a two channel system for data recording where two azimuth read heads are used to derive the tracking error from the time skew between the read data clocks of the channels. The timing pulses are not so easily available as the sync pulses used in other prior art devices. However, this device does not require separate azimuth read heads, since the two write heads also have azimuth angles of opposite sign. The signals are either read back while writing by two aligned read heads with the same azimuth angles, or by the same write heads in simpler tape drives. An advantage of this system is greater information packing density, since no guard bands between tracks in the information area of the tape are needed. This device, however, is limited in the linear tracking range since it requires a very accurate open-loop mechanical positioning mechanism in addition to the servo mechanism. An additional problem is the compensation or calibration of the time skew between the channels especially when reading tapes written in other drives. Yet another disadvantage is that if backward compatibility with older tape formats written without azimuth is to be maintained, at least one set of zero-azimuth read and write gaps must be provided. If one of the two write gaps is without an azimuth angle, half of the timing error is present as compared to a double azimuth scheme. The crosstalk from neighbor tracks will also increase.

System and a method for optically detecting an edge of a tape


An apparatus for elevating the head and torso of a patient confined to a fluidized patient support system. A head cushion assembly, a knee gatch assembly and a control assembly are integrated with any known fluidized patient support system and preferably integrated, at least in part, with the cover sheet of the chosen patient support system. In operation, the invention may be utilized to raise and/or lower a patient""s head and torso, in 15xc2x0 steps, to any inclination from supine to approximately 45xc2x0. In implementations utilizing the knee gatch assembly, the patient is effectively prevented from sliding during inclination even to the highest of angles. The controls are conveniently provided on a handheld unit for easy access and operation by caregivers and patient alike.

The present invention relates to fluidized patient support systems. More specifically, the present invention relates to an apparatus for providing up to 45xc2x0 to the head and torso of a patient confined to a fluidized hospital bed, while preventing sliding of the patient and without complete loss of the therapeutic benefit provided by the bed system.
Fluidized patient support systems are generally recognized by those of ordinary skill in the art as providing the most ideal support surface available for reduction of bed to patient interface pressures. As is well known in the art, these systems generally comprise a relatively rigid tank containing a large mass of fluidizable media, such as tiny polyurethane coated glass beads, retained under the cover of at least one but preferably two air-permeable sheets. A provided blower assembly is utilized to xe2x80x9cfluidizexe2x80x9d the operable media, usually by forcing a volume of air from the bottom of the tank and through the media. Exemplary fluidized patient support systems include the trade name xe2x80x9cELITExe2x80x9d series commercially available from Kinetic Concepts, Inc. of San Antonio, Tex. under the trademark xe2x80x9cFLUIDAIRxe2x80x9d and the trademark xe2x80x9cCLINITRONxe2x80x9d series commercially available from Hill-Rom of Charleston, S.C.
Unfortunately, the near-ideal interface surface provided by fluidized patient support systems is not conducive to providing the patient with other facilities for increased comfort, such as a head and torso elevation function. Due to the minimized friction concomitant the reduced interface pressure, the patient has a dramatic tendency to slide toward the foot of the bed at any time force is applied in a longitudinal direction. Consequently, raising the head and torso of the patient will generally result in cramping of the patient""s feet against the foot of the bed, which is uncomfortable and in extreme cases may even result in pressure sores and the like. It is therefore a specific object of the present invention to provide an apparatus for use in a fluidized patient support system whereby the patient is automatically prevented from sliding while raising the patient""s head and torso.
While the head and torso of patient""s in fluidized patient support systems have previously been raised by inserting foam cushions and the like beneath the patient, this method is considered undesirable. Much of the therapeutic benefit provided by fluidized patient support systems derives from the flow of air adjacent the patient""s skin. It is therefore a specific object of the present invention to provide an apparatus for use in a fluidized patient support system whereby the patient""s head and torso may be raised without complete loss of the therapeutic benefit available in the head and torso areas.
In accordance with the foregoing objects, the present invention generally comprises a an apparatus for elevating the head and torso of a patient using a fluidizable patient support system includind an inflatable upper body lift at the head end of the patient support system for elevating the head and torso of a patient using the patient support system. The inflatable upper body lift may comprise a plurality of inflatable chambers which may be stacked one atop another. In at least one embodiment, the inflatable chambers are removably attached one to another and in at least one other embodiment the inflatable chambers comprise a low air loss material. The entire inflatable upper body lift may removably attached to the fluidizable patient support system.
In a further embodiment of the present invention, a lower body lift is provided between the upper body lift and the leg end of the fluidizable patient support system. The lower body lift, which may comprise a removably attached inflatable chamber, is adapted to automatically prevent sliding of the patient during elevation of the patient""s head and torso.
In yet a further embodiment of the present invention, the lower body lift and at least one upper body lift inflatable chamber are in fluid communication with a common source of pressurized fluid. This common source may be automatically regulated to maintain a selected patient support surface firmness.
Many other features, objects and advantages of the present invention will be apparent to those of ordinary skill in the relevant arts, especially in light of the foregoing discussions and the following drawings, exemplary detailed description and appended claims.

Apparatus for elevation of head and torso in fluidized patient support


A strap fastener for releasably connecting a strap, cord or belt on a garment article is disclosed, the fastener comprising a base member, a strap retainer member and a slider. The base member has an upper plate and a lower plate defining therebetween a guide channel through which the slider is movable. The slider has a guide rail at such a lower edge of a side flange which lies above the lower surface of the base member. A hook is formed, extending integrally from the lower plate of the base and releasably engageable with the slider through a ridge-and-groove formation alternately provided on the hook and the slider.

1. Field of the Invention
This invention relates to a strap fastener for releasably connecting a strap, cord or belt on a garment article such as a bag, sack, sports wear and the like.
2. Prior Art
There are known numerous fastening devices for releasably connecting opposite terminal ends of an elongate strap or belt attached to a bag or other garment articles. A typical example of one such fastening device over and relating to which the present invention contemplates an improvement is disclosed in Japanese Patent Publication No. 62-39285 in which it was proposed to use a fastening device in the form of a plastic snap hook engageable with a ring attached to a handbag, a sack or the like. The snap hook is comprised of a base member having at one of its ends a folded-back hook portion, at the other end a resilient plate-like tongue portion and a slider movable over and along the tongue portion between a position in which the hook is open and a position in which the hook is closed, the arrangement being that the slider is urged by the resilient force of the tongue normally toward the hook to close the latter and moved by the wearer's fingers against the tension of the tongue retractively away from the hook to open the latter. Since the slider is arranged to reciprocate with its lower peripheral wall protruding beyond the lower surface of the base member, the portion of the snap hook at which the slider is connected to the base member becomes objectionably thick and bulky making the whole device look unsightly, a disadvantage particularly where the snap hook is used in connection with a ladies' shoulder-bag or similar ornamental garment article. Another drawback of the prior art device is that since the plate-like tongue yields a relatively strong resilient action upon the slider to urge the latter into snapping engagement with the hook, so much finger pressure is required to retract the slider away from the hook to provide an opening for inserting therethrough the connecting ring of the bag.


A method of controlling a battery electric vehicle includes displaying an energy consumption parameter to a vehicle operator. The energy consumption parameter is based on a filtered energy usage rate. The filtered energy usage rate is defined by a weighted incremental energy consumption rate measured over a first distance and an average energy consumption rate learned over a second distance. The second distance exceeds the first distance.

A battery electric vehicle (BEV) may be propelled by operation of an electric machine configured to receive electrical power from an on-board battery. The battery may be charged with electrical power from a utility grid or other off-board power source. A BEV driver may wish to accurately know the expected vehicle drive range before the battery is drained.

Energy consumption rate in distance domain


A DC offset cancellation block is provided for canceling a DC offset in a signal path. The signal path may include an input and an output. The DC offset cancellation block may include an active integrator coupled between the input and the output to provide a negative feedback to the signal path. The active integrator may include an operational-amplifier (op-amp), a capacitive component with a capacitance C, and a resistive component with a resistance R, and the capacitive component may be coupled to the op-amp via a closed feedback loop. The DC offset cancellation block may also include a first amplifier with a gain of GA coupled with the capacitive component in the closed feedback loop such that a RC time constant of the active integrator is changed from RC to RCGA.

Integrated circuits used in communication devices, such as wireless communication devices, are often required to perform signal processing in environments that are very sensitive to the introduction of a signal offset, such as noise. The signal offset represents a deviation in the intended value of a circuit reference signal introduced in the processes of transmitting and receiving signals. The signal offset may affect the DC performance of a circuit by causing a presence of an offset current or offset voltage that is indistinguishable from the reference signal, which may further lead to undesired effects, such as circuit saturation and, potentially, circuit malfunction. For example, in highly integrated wireless transceivers, DC offset may be introduced in radio frequency (RF) front end circuitries or in baseband circuitries. Such DC offset may be amplified by various amplifiers in the baseband circuitries and may cause saturation and/or undesired interference in the baseband circuitries.
Techniques have been developed to reduce or cancel DC offset by using alternating current (AC) coupled or single pole low-pass filters. For example, U.S. Pat. No. 6,509,777 issued to Razavi et al. on Jan. 21, 2003, discloses a DC offset reduction circuit using a AC coupled feedback loop with a programmable gain transconductance amplifier of programmable gain. However, such conventional techniques often require a large RC time constant, which may result in a large die footprint or size for the DC offset reduction circuit and an increase in DC offset reduction time. Under certain circumstances, the increased time for reducing or canceling the DC offset may be undesirable in many wireless communication systems, such as wireless local area network (WLAN) or world interoperability for microwave access (WiMAX), etc.
Methods and systems consistent with certain features of the disclosed embodiments are directed to solving one or more of the problems set forth above.

Industrial Technology Research Institute


The invention relates to roller blind slats having a profile which is shaped by flat sheet metal in a rolling step. A single-pieced roller blind body is associated with the roller blind slats. The roller blind body is formed with a slot on the underside thereof and a hooked strip is provided on the top edge thereof. The slot part is approximately 20% on the total surface of the roller blind slats.

It is a familiar practice to also use roller curtains made from laths for sun protection. For this purpose, a user will let down the roller curtain a bit, so that the roller curtain casts an appropriate shadow. Relatively little light gets through the roller curtain itself. The ratio of slots to the overall surface is about 1.5%. As a result, the roller curtain generally cannot be let down entirely for sun protection purposes since the resulting darkness would be too deep.
Known roller curtains are made from individual laths with a bottom with an undercut channel and a hooked slat at the top. Extremely tiny slots, relative to the surface of the roller curtain, are situated in the area of the hooked slat. Thus, larger slots cannot be provided on the main body of the lath since it no longer would be possible to control the admission of light by rolling the roller curtain up or down.
Known laths have a roll shaped profile that is often packed with foam or provided with crosspieces running in the longitudinal direction of the lath in order to achieve the necessary strength.


A method for the removal of aqueous phase selenite and selenate species using TiO2 assisted photocatalysis employing the use of artificial light, or solar radiation, in conjunction with EDTA as a hole scavenger. Among the two processes, UV-lamp assisted photocatalysis has the highest efficiency comparatively followed by solar light assisted photocatalysis. TiO2 mediated photocatalysis in conjunction with EDTA as an h+ scavenging agent is an efficient technique for selenium ion removal.

1. Technical Field
The present invention relates to a method for using ethylenediaminetetraacetic acid (EDTA) and unmodified TiO2 for the photocatalyic removal of selenium-containing materials from an aqueous solution in which EDTA is used as a hole scavenger and the method includes the use of artificial light, or solar radiation, photocatalysis for the removal of aqueous phase selenite and selenate species.
2. Description of the Related Art
The "background" description provided herein is for the purpose of generally presenting the context of the disclosure. Work of the presently named inventors, to the extent it is described in this background section, as well as aspects of the description which may not otherwise qualify as prior art at the time of filing, are neither expressly or impliedly admitted as prior art against the present invention.
Enhanced industrial practices such as mining, fossil fuel extraction/use, etc., mobilize an otherwise bound selenium species into a natural environment. For example, erosion of soils due to agricultural practices leads to increased selenium in ground and surface water (D. Wang, G. Alfthan, A. Aro, P. Lahermo, and P. Vaananen, The impact of selenium fertilisation on the distribution of selenium in rivers in Finland, Agric., Ecosys. Environ. 50 (1994), pp. 133-149-incorporated herein by reference in its entirety) whereas leaching from mining sites' soils/rocks also releases selenium species into natural waterways (J. Högberg and J. Alexander, Chapter 38—Selenium, in Handbook on the Toxicology of Metals, Gunnar F. Nordberg, Bruce A. Fowler, Monica Nordberg and Lars Friberg, Third Edition, Academic Press, Burlington, 2007, pp. 783-807; ATSDR, Toxicological profile for selenium, ATSDR, 2003; P. Zhang and D. L Sparks, Kinetics of selenate and selenite adsorption/desorption at the goethite/water interface, Environmental Science & Technology. 24 (1990), pp. 1848-1856—each incorporated herein by reference in its entirety). Furthermore, effluents from industries such as oil refineries & power plants and use of selenium based chemicals in several industrial processes, also discharge selenium into the natural environment. Though selenium is an essential micronutrient, a relatively thin margin exists between selenium amounts resulting in deficiency and toxicity and a significant exposure causes serious ecological concerns (U. Tinggi, Essentiality and Toxicity of Selenium and its Status in Australia: a Review, Toxic. Let. 137 (2003), pp. 103-110; J. O. Hall, Chapter 34—Selenium, in Veterinary Toxicology, C. G. Ramesh, Academic Press, Oxford, 2007, pp. 453-460; U. Tinggi, Selenium: its role as antioxidant in human health, Environ Health Prey. Med. 13 (2008), pp. 102-108; R. A. Sunde, Selenium", in: Present Knowledge in Nutrition, Bowman, B. A. and Russell, 9th edition, R. M., ILSI Press, Washington, D.C., 2006, pp. 480-497; A. D. Lemly, Ecosystem recovery following selenium contamination in a freshwater reservoir, Ecotox. Environ. Safi 36 (1997), pp. 275-281; A. D. Lemly, Aquatic Hazard of Selenium pollution from Mountaintop Removal Coal Mining, Appalachian Cent. For the Econ. & the Environ. And the Sierra Club, 2009. Available at http://www.filonverde.org/images/informe_selenio_en_minas_a_cielo_abierto.pdf; R. L. J. P. Skorupa and L. A. Peltz, Areas Susceptible to Irrigation-Induced Selenium Contamination of Water and Biota in the Western United States, U.S. Dept. of the Interior, U.S. Geological Survey 1999. Available at http://pubs.usgs.gov/circ/circ1180/—each incorporated herein by reference in its entirety). The respective selenium drinking water and wastewater discharge standards are very stringent.
Typically selenium occurs in four natural oxidation states: i.e., elemental selenium (0), selenide (−2), selenite (+4) and selenate (+6) (F. Seby, M. Potin-Gautier, E. Giffaut, G. Borge and O. F. X. Donard, A Critical Review of Thermodynamic Data for Selenium Species at 25° C., Chem. Geo. 171 (2001), pp. 173-194—incorporated herein by reference in its entirety). Out of these selenite and selenate (inorganic oxyanion species) are the most dominant in the aqueous phase because of their high solubility and mobility. Selenate is most dominant because of its low adsorption on to naturally occurring surfaces and is not well retarded in the natural environment while selenite's mobility is mainly governed by adsorption/desorption processes occurring on to various solid surfaces such as metal oxyhydroxides (D. G. Barceloux, Selenium, J. Toxicol Clin Toxicol. 37 (1999): 145-172—incorporated herein by reference in its entirety). Several technologies including adsorption, reverse osmosis, nano-filtration, evaporation ponds, ferrous hydroxide treatment, biological processes, and constructed wetlands have been used for the above mentioned selenium oxyanions removal, with each of these methods having its own advantages and disadvantages (L. Twidwell, J. McCloskey, H. Joyce, E. Dahlgren, and A. Hadden, Removal of selenium oxyanions from mine waters utilizing elemental iron and galvanically coupled metals, In Innovations in Natural ResourceProcessing—Proceedings of the Jan. D. Miller Symposium; SSEMP, Draft technologies and management techniques to limit exposures to selenium, available at http://www.water.ca.gov/saltonsea/historicalcalendar/wg/03.04.2005/SeleniumMgmtTech.pdf—each incorporated herein by reference in its entirety). Titanium dioxide (TiO2) assisted photocatalytic degradation (PCD) which is an advanced treatment technology has also been widely studied for the removal of both organic and inorganic pollutants from contaminated water bodies (A. Fujishima, T. N. Rao and D. A. Tryk, Titanium dioxide photocatalysis, J. Photochem. Photobio. C: Photochem. Rev. 1 (2000): pp. 1-21; K. Hashimoto, H. Irie, and A. Fujishima, TiO2 photocatalysis: a historical overview and future prospects, AAPS Bulletin. 17 (2007), pp. 8269-8285—each incorporated herein by reference in its entirety). When feasible, the PCD process offers several advantages including minimum waste by-products, low operational temperature, use of a non-toxic and reusable photocatalyst, no specific chemical requirement, and possible use of sun light as an energy source.
Furthermore the Kingdom of Saudi Arabia (KSA) is fortunate to have an abundant year round supply of solar energy and KSA is one of the only few regions in world that receive the highest amount of solar radiation (World Solar Commission, World Solar Programme 1996-2005: Africa (ASP). Mechanisms of Implementation (An Outline), Prepared by the Secretariat of the World Solar Commission, (2001)—incorporated herein by reference in its entirety). Among many other uses, this virtually unlimited source of energy can be utilized for environmental cleanup as well. Use of solar radiation for several environmental applications including advanced wastewater treatment have also been reported for other locations (J. Blanco, S. Malato, P. Fernandez-Ibañez, D. Alarcon, W. Gernjak, and M. I. Maldonado, Review offeasible solar energy applications to water processes, Renewable and Sustainable Energy Reviews 13 (2009), pp. 1437-1445; Julian Blanco-Galvez, Pilar Fernández-Ibáñez and Sixto Malato-Rodríguez, Solar photocatalytic detoxification and disinfection of water: recent overview, J. Sol. Energy Eng. 129 (2006), pp. 4-15; Antonio E. Jimenez, Claudio A. Estrada, Alma D. Cota, and Alberto Román, Photocatalytic degradation of DBSNa using solar energy, Solar Energy Materials and Solar Cells 60 (2000), pp. 85-95; C. Karunakaran and R. Dhanalakshmi, Semiconductor-catalyzed degradation of phenols with sunlight, Solar Energy Materials and Solar Cells 92 (2008), pp. 1315-1321; S. Malato. P. Fernández-Ibáñez, M. I. Maldonado, J. Blanco, and W. Gernjak, Decontamination and disinfection of water by solar photocatalysis: Recent overview and trends, Catalysis Today 147 (2009), pp. 1-59; B. Neppolian, H. C. Choi, S. Sakthivel, B. Arabindoo, and V. Murugesan, Solar light induced and TiO2 assisted degradation of textile dye reactive blue 4, Chemosphere 46 (2002), pp. 1173-1181; S. S. Priya, S. Shanmuga M. Premalatha, and N. Anantharaman, Solar Photocatalytic Treatment of Phenolic Wastewater Potential, Challenges and Opportunites. Journal of Engineering and Applied Sciences, 3 (2008). pp. 36-41; M. Saquib, M. Abu Tariq, M. M. Hague, and M. Muneer, Photocatalytic degradation of disperse blue 1 using UV/TiO2/H2O2 process, Journal of Environmental Management 88 (2008), pp. 300-306; C. Sichel, P. Fernández-Ibañez, M. de Cara, and J. Tello, Lethal synergy of solar UV-radiation and H2O2 on wild Fusarium solani spores in distilled and natural well water," Water Research 43 (2009), pp. 1841-1850—each incorporated herein by reference in its entirety). As mentioned above, one such advanced oxidation process (AOP) that can be used to treat industrial wastewaters includes solar radiation energized titanium dioxide (TiO2) assisted photocatalytic degradation process or TiO2-Photocatalysis (SPCD).
For example the SPCD technology has been widely studied in many regions around the globe (Detlef Bahnemann, Photocatalytic water treatment: solar energy applications, Solar Energy 77 (2004), pp. 445-459; Pilar Fernandez-Ibañez, Sixto Malato, and Octav Enea, Photoelectrochemical reactors for the solar decontamination of water, Catalysis Today 54 (1999), pp. 329-339; S. Malato, J. Blanco, C. Richter, B. Braun, and M. I. Maldonado, Enhancement of the rate of solar photocatalytic mineralization of organic pollutants by inorganic oxidizing species, Applied Catalysis B: Environmental 17 (1998), pp. 347-356; S. Malato, J. Blanco, C. Richter, B. Milow, and M. I. Maldonado, Solar photocatalytic mineralization of commercial pesticides: Methamidophos, Chemosphere 38 (1999), pp. 1145-1156; S. Malato, J. Caceres, A. Agiiera, M. Mezcua, D. Hernando, J. Vial, and A. R. Fernandez-Alba, Degradation of Imidacloprid in Water by Photo-Fenton and TiO2 Photocatalysis at a Solar Pilot Plant: A Comparative Study, Environmental Science & Technology 35 (2001), pp. 4359-4366; S. Malato, J. Blanco, A. Vidal, P. Fernandez, J. Caceres, P. Trincado, J. C. Oliveira, and M. Vincent, New large solar photocatalytic plant: set-up and preliminary results, Chemosphere 47 (2002), pp. 235-240; M. Mehos, C. Turchi, J. Pacheco, A. J. Boegel, T. Merrill, and R. Stanley, Pilot-scale study of the solar detoxification of VOC-contaminated groundwater, Technical Report submitted at American Institute of Chemical Engineers (AIChE) summer national meeting, Minneapolis, Minn. (United States) (1992); J. E. Pacheco and C. E. Tyner, Enhancement of processes for solar photocatalytic detoxification of water, ASME international solar energy conference, Miami, Fla. (USA) (1990); W. Scott Rader, Ljiljana Solujic, Emil B. Milosavljevic, James L. Hendrix, and John H. Nelson, Sunlight-induced photochemistry of aqueous solutions of hexacyanoferrate(II) and -(III) ions, Environmental Science & Technology 27 (1993), pp. 1875-1879; Didier Robert and Sixto Malato, Solar photocatalysis: a clean process for water detoxification, Science of The Total Environment 291 (2002), pp. 85-97; Manuel Romero, Julián Blanco, Benigno Sanchez, Alfonso Vidal, Malato Sixto, Ana I. Cardona, and Elisa Garcia, Solar photocatalytic degradation of water and air pollutants: challenges and perspectives, Solar Energy 66 (1999), pp. 169-182; Julian Blanco Galvez and Sixto Malato Rodriguez, Solar detoxification in Renewable energy series, edited by Julian Blanco Galvez and Sixto Malato Rodriguez, UNESCO (2003); Susana Flores Villanueva and Susana Silva Martínez, TiO2-assisted degradation of acid orange 7 textile dye under solar light, Solar Energy Materials and Solar Cells 91 (2007), pp. 1492-1495; Archis A. Yawalkar, Dhananjay S. Bhatkhande, Vishwas G. Pangarkar, and Anthony ACM Beenackers, Solar-assisted photochemical and photocatalytic degradation of phenol, Journal of Chemical Technology & Biotechnology 76 (2001), pp. 363-370—each incorporated herein by reference in its entirety). The SPCD technology incorporates use of the catalyst TiO2 and solar UV light to degrade the target pollutant. Use of solar radiation instead of artificial UV light lamps during the SPCD advanced oxidation process is expected to be efficient and economical in regions that are rich in solar energy such as KSA. Hence the abundant solar energy natural resource of Kingdom of Saudi Arabia offers an opportunity to utilize it for respective environmental applications. Considering the concerns related with selenium pollution an appropriate treatment of respective streams is required to mitigate those adverse concerns and also to meet the selenium discharge limits.
The essential or toxic character of selenium depends on its concentration in food, water and other living organisms, as well as its chemical speciation and distribution in soils, wetlands and aqueous ecosystems. Atmospheric deposition, surface runoff, and subsurface drainage account for selenium contamination in surface water. Use of fossil fuels also introduces selenium species into natural environment.
When present, Se (IV), selenite and Se (VI), selenate are typical selenium species in respective water bodies.
Selenium can occur with and replaces sulfur because of the similarities in their chemical properties. Selenium combines with metals and many nonmetals directly or in aqueous solution. (Ana Benedicto, Tiziana Missana, and Claude Degueldre, Predictions of TiO2 driven migration of Se(IV) based on an integrated study of TiO2 colloid stability and Se(IV) surface adsorption, Science of the Total Environment 449 (2013), pp. 214-222—incorporated herein by reference in its entirety).
In the 13th century, Marco Polo noticed the presence of certain poisonous plants that had serious effects on the beasts that consume it in the province of Shanxi. This description made before the discovery of selenium, is probably a symptom of its toxicity (Helina Hartikainen, Biogeochemistry of selenium and its impact on food chain quality and human health, J. of Trace Elements in Medicine and Biology 18 (2005) pp. 309-318—incorporated herein by reference in its entirety).
Selenium poisoning clinical signs include hair loss, fingernails changes and brittleness, gastrointestinal disturbances, skin rash, garlic breath, and abnormal functioning of the nervous system (Miguel Navarro-Alarcon and Carmen Cabrera-Vique, Selenium in food and the human body: A review, Sc. of the Total Env. 400 (2008) pp. 115-141—incorporated herein by reference in its entirety).
The health effects are recorded on humans as a result of high selenium status (M. P. Rayman, Selenium and human health, The Lancet 379 (2000) pp. 1256-1268—incorporated herein by reference in its entirety).
Maximum contaminant levels for selenium have been made by different authorities based on the extent of the results of some field studies. MCLs for WHO, Health Canada and Australia are set at 0.01 mg/L while USEPA currently has MCLs of 0.05 mg/L (Health Canada, Environmental and workplace health: Selenium, available at http://www.hc-sc.gc.ca/ewh-semt/pubs/water-eau/selenium/index-eng.php; WHO, Selenium in drinking-water, World Health Organization (2011); NPI, Selenium & compounds: Health effects, Commonwealth of Australia—each incorporated herein by reference in its entirety). However, a more stringent freshwater discharge standard of 5 μg/L is set up by EPA (USEPA, National recommended water quality criteria, (1995)—incorporated herein by reference in its entirety).
PCD Process
TiO2 used in the photocatalytic degradation (PCD) process is an n-type semiconductor and both the anatase and rutile crystal forms of TiO2 have been widely used in the PCD studies. Furthermore TiO2 possesses a void energy region also known as band gap (BG) between its valence band (VB) and conduction band (CB), extending from the top of the electronfilled VB to the bottom of the vacant CB. Thus when a TiO2 particle is exposed to a UV light source with energy hν equivalent to or higher than the bandgap energy (BGE) the VB electrons are transferred to CB thus creating an electron-hole pair (e−/h+) as given in reaction 2-1:TiO2+hν→e−+h+  (2-1)e−-h+ recombination can occur in the bulk and/or on the surface (Equation 2-2). When the h+ and e− are successfully transferred to the TiO2 surface, the h+ can oxidize an electron donor such as an organic compound (Equation 2-3) while the e− can reduce an electron acceptor e.g., selenite (Equation 2-4) and selenate (Equation 2-5).e−+h+→heat  (2-2)organic compound+h+→oxidized products  (2-3)SeO32−+6H++4e−Se0+3H2O  (2-4)SeO42−+8H++6e−Se0+4H2O  (2-5)
Furthermore reactions 2-6 and 2-7 are also typically used to represent the naked-TiO2 surface in contact with the water molecules (W. Stumm, Aquatic Surface Chemistry: Chemical Processes at the Particle-Water Interface, Wiley, (1987)—incorporated herein by reference in its entirety):Ti—OH2+Ti—OH+H+  (2-6)Ti—OHTi—O−+H  (2-7)
The h+ species produced in reaction 2-1 is electron deficient and hence reacts with an adsorbed hydroxyl molecule OH− on the TiO2 surface to produce an OH. radical (Reaction 2-8):Ti—OH−+h+→Ti—OH  (2-8)
The OH radicals are powerful and non-selective oxidants that can typically simultaneously remove both organic and inorganic pollutants from the concerned wastewaters. However direct oxidation of organic compounds by holes/h+ has been reported as well. Furthermore the electrons/e− produced in Equation 2-1 could be consumed by a suitable electron acceptor such as O2 or a metal species. In case of selenite or selenate, the e species could possibly be utilized for their reduction and consequent removal from the aqueous phase (Equations 2-4 and 2-5).
An earlier work on TiO2 photocatalytic reduction of selenium oxyanions was carried out by E. Kikuchi (E. Kikuchi, S. Itou, M. Kobayasi and H. Sakamoto, Reduction and removal of selenate ion by TiO2 photo-catalyst, J. NIRE. 6 (1997), pp. 173-177—incorporated herein by reference in its entirety). Since then these systems have been examined by several other groups (S. Sanuki, T. Kojima, K. Arai, S. Nagaoka and H. Majima, photocatalytic reduction of selenate and selenite solutions using TiO2 powders, Met. Mat. Trans. B. 30 (1999), pp. 15-20; S. Sanuki, K. Shako, S. Nagaoka and H. Majima, Photocatalytic reduction of Se ions using suspended anatase powders, Mat. Trans., JIM. 41 (2000), pp. 799-805; T. Tan, D. Beydoun and R. Amal, Effect of organic holes scavengers on the photocatalytic reduction of selenium anions, J. Photochem. Photobio. A: Chem. 159 (2003), pp. 273-280—each incorporated herein by reference in its entirety). Many of these studies have also investigated the role of hole (h+) scavengers such as formic acid during TiO2 assisted photocatalytic reduction of selenite and selenate and report significant removal of selenium contamination from the aqueous phase (V. N. H. Nguyen, R. Amal and D. Beydoun, Photocatalytic reduction of selenium ions using different TiO2 photocatalysts, Chem. Eng. Sci. 60 (2005), pp. 5759-5769; V. N. H. Nguyen, D. Beydoun and R. Amal, Photocatalytic reduction of selenite and selenate using TiO2 photocatalysts, Journal of Photochem. and Photobio. A: Chem. 171 (2005), pp. 113-120—each incorporated herein by reference in its entirety). Recently Aman et al. (N. Aman, T. Mishra, J. Hait and R. K. Jana, Simultaneous photoreductive removal of copper (II) and selenium (IV) under visible light over spherical binary oxide photocatalyst, J. Haz. Mater. 186 (2011), pp. 360-366—incorporated herein by reference in its entirety) also reported using a modified Ti—Zr based photocatalyst and EDTA (as a hole scavenger) for selenite/selenate removal from the aqueous phase. Nevertheless the role of EDTA as a hole scavenger for the removal of respective selenium species using unmodified TiO2 photocatalysis, has not been investigated. Aman et al. report on simultaneous photo-reductive removal of copper (II) and selenium (IV) using Ti, Ti—Zr, and Ti—Si binary oxide photocatalysts and visible light under a varying set of conditions including single and mixed copper and selenium systems. The prepared catalysts had high specific surface area and were mesoporous. TiZr-10 was noted to be the best photocatalyst. Also pH 3 was noted to be the optimum and yielded highest photocatalytic selenite reduction in a mixed solution. Out of many hole scavengers tested, formic acid and ethylenediaminetetraacetic acid (EDTA) were best for the reduction of selenium oxyanions. The h+ species produced in Equation 2-1 are consumed by the h+ scavengers, resulting in reduced e−/h+ recombination (Equation 2-2) and thus leaving more e− species for reduction of selenite (analogous to Equation 2-4). Furthermore for single pollutant system, formic acid yielded better results for Se(IV) reduction whereas EDTA was noted to be better for Cu(II) reduction. However for mixed systems, both formic acid and EDTA showed better metal reduction results and the copper selenide was noted to be deposited at the catalyst surface. Nguyen et al. noted that in the presence of formic acid as a hole scavenger both selenite and selenate were photoreduced to Se(0) in illuminated TiO2 suspensions. Findings from the UV-Vis reflectance indicated that compared to pure TiO2 the Se/TiO2 sample had a red-shift; an additional absorbance peak at approx. 680 nm was assigned to Se(0). The elemental selenium species accumulated on the TiO2 particles either in a particulate or film form. It was proposed that the formation of Se(0) particles was due to a chemical reaction between Se(IV) and Se2− whereas a direct reduction of Se(IV) by the conduction band electrons (TiO2) resulted in the formation of a Se(0) film. The Se2− species was suggested to result either from photoreduction of Se(0) or because of reduction of Se(IV). Shi et al. who investigated selenite sorption on TiO2 indicated that selenite sorption is a function of pH and its kinetics can be given as a pseudo-second-order model (K. Shi, X. Wang, Z. Guo, S. Wang, and W. Wu, Se(IV) sorption on TiO2: Sorption kinetics and surface complexation modeling, Colloids and Surf. A: Physicochem. and Eng. Asp. 349 (2009), pp. 90-95—incorporated herein by reference in its entirety). The authors also employed the constant capacitance model to predict selenite sorption on to TiO2. Tan et al. also investigated the reduction of selenium oxyanions (selenite and selenate) to elemental selenium using TiO2 assisted photocatalysis. The authors employed several hole scavenging agents including acetic acid, methanol, ethanol, salicylic acid, formic acid, and sucrose. Significant reduction of selenium oxyanions was possible using ethanol, formic acid, and methanol, with following order: formic acid >methanol >ethanol. This high capability of formic acid to reduce selenium oxyanions was explained based on its effective mineralization, formation reducing radicals, and adsorption of both the selenium species and formic acid onto TiO2. Insignificant adsorption of ethanol and methanol was explained based on competitive selenium species adsorption on to the TiO2 surface, resulting in reduced role of hole scavenger ethanol and methanol resulting in their reduced efficiency. For the formic acid case the optimum pH for selenium oxyanions photoreduction was 3.5-4. For methanol and ethanol the optimum pH value was 2.2.
Tan et al. investigated the PCD initiated reduction of selenate using TiO2 and Ag-loaded TiO2 and formic acid; selenate was successfully reduced to elemental selenium species employing the said photocatalysts and hole scavenger. The formation of Se2− followed H2Se formation using pure TiO2 whereas using Ag-loaded TiO2 photocatalyst H2Se and selenate reduction were noted to occur in parallel. Also pH 3.5 was noted to be optimum for reduction of selenate using 0.5% Ag loading. This high efficiency was explained based on electronic changes from TiO2—Ag—Se interaction and decreased e−/h+ recombination. In another study, Tan et al. report that the adsorption of formate and selenate onto TiO2 surface is a prerequisite for selenate reduction to elemental selenium which could further be reduced to H2Se (after selenate reduction to elemental form) (T. T. Y. Tan, and D. Beydoun, Photocatalytic reduction of Se(VI) in aqueous solutions in UV/TiO2 system: Importance of optimum ratio of reactants on TiO2 surface, J. Mol. Cat. A: Chem. 202 (2003), pp. 73-85—incorporated herein by reference in its entirety). The authors also report for optimum selenate reduction, a 3:1 formate:selenate ratio (on to TiO2 surface). This ratio could be maintained by controlling factors such as concentration of respective species and the aqueous phase pH. Also the noted 3:1 of formate:selenate ratio (on to TiO2 surface) strongly co-related with the stoichiometric ratio of 3 moles of formic acid to 1 mole of selenate for effective reduction. Tan et al. described selenate reduction rates in presence of formic acid employing Langmuir-Hinshelwood competitive adsorption models for selenate and formate ions onto TiO2 surface (T. T. Y. Tan, and D. Beydoun, Photocatalytic reduction of Se(VI) in aqueous solutions in UV/TiO2 system: Kinetic modeling and reaction mechanism, J. Phy. Chem. B. 107 (2003), pp. 4296-4303—incorporated herein by reference in its entirety). The respective models allowed for the modeling of formic acid and selenate adsorption on to TiO2. Furthermore a 3:1 formate:selenate ratio (on to TiO2 surface) was also obtained using the kinetic modeling exercise.
Zhang et al. also investigated sorption of selenium species on to TiO2 (L. Zhang, N. Liu, L. Yang, and Q. Lin, Sorption behavior of nano-TiO2 for the removal of selenium ions from aqueous solution, J. Haz. Mater. 170 (2009), pp. 1197-1203—incorporated herein by reference in its entirety). The maximum sorption was noted at pH 2-6. Also the sorption reached equilibrium within 5 min. The adsorption could be described both by boundary layer diffusion and intra-particle diffusion. Furthermore the adsorption kinetics results showed a second order kinetic model and the Langmuir adsorption isotherm was useful in modeling the respective findings.
Though many solar photocatalytic degradation (SPCD) studies have been reported on several aqueous phase pollution control issues, removal of selenite and selenate using SPCD process (using naked TiO2 and EDTA) has not been investigated. Augugliaro et al. studied cyanide degradation employing the TiO2 assisted photocatalysis using sun light as the energy source (V. Augugliaro, J. Blanco Gálvez, J. Cáceres Vázquez, E. Garcia López, V. Loddo, M. J. López Muñoz, S. Malato Rodriguez, G. Marci, L. Palmisano, M. Schiavello, and J. Soria Ruiz, Photocatalytic oxidation of cyanide in aqueous TiO2 suspensions irradiated by sunlight in mild and strong oxidant conditions, Catalysis Today 54 (199), pp. 245-253—incorporated herein by reference in its entirety). The authors report successful degradation of cyanide with nitrite, nitrate, cyanate, and carbonate as the reaction end products. In mixed systems containing both cyanide and phenol, the overall cyanide degradation efficiency decreased. Banu et al. investigated treatment of dairy wastewater by using a hybrid of biological and SPCD technologies (J. Rajesh Banu, S. Anandan, S. Kaliappan, and Ick-Tae Yeom, Treatment of dairy wastewater using anaerobic and solar photocatalytic methods, Solar Energy 82 (2008), pp. 812-819—incorporated herein by reference in its entirety). Using only biological treatment the authors noted about 84% reduction in the chemical oxygen demand (COD) value of respective wastewater. However an integration of biological and solar photocatalytic degradation processes caused 95% COD removal from the dairy wastewater. Choi et al. who studied degradation of several aqueous phase polychlorinated dibenzo-p-dioxins (PCDDs), report good removal of octa-chlorinated dibenzo-p-dioxin using the SPCD process (Wonyong Choi, Soo Jin Hong, Yoon-Seok Chang, and Youngmin Cho, Photocatalytic Degradation of Polychlorinated Dibenzo-p-dioxins on TiO2 Film under UV or Solar Light Irradiation, Environmental Science & Technology 34 (2000), pp. 48104815—incorporated herein by reference in its entirety). Furthermore the SPCD process was noted to be as effective as a 200 W mercury lamp for the respective application.
Cho et al. studied ex-situ treatment of petroleum contaminated groundwater at a gas station site using the solar radiation energized PCD process (Il-Hyoung Cho, Lee-Hyung Kim, Kyung-Duk Zoh, Jae-Hong Park, and Hyun-Yong Kim, Solar photocatalytic degradation of groundwater contaminated with petroleum hydrocarbons, Environmental Progress 25 (2006), pp. 99-109—incorporated herein by reference in its entirety). The authors report more than 70% reduction in the total petroleum hydrocarbons and BTEX compounds (benzene, toluene, ethylbenzene, xylene). Curco et al. report notable phenol removal using the SPCD technology that also showed linear dependence on the square root of photonic flow entering the wastewater treatment reactor (D. Curcó, S. Malato, J. Blanco, J. Giménez, and P. Marco, Photocatalytic degradation of phenol: Comparison between pilot-plant-scale and laboratory results," Solar Energy 56 (1996), pp. 387-400—incorporated herein by reference in its entirety). Furthermore the phenol degradation was noted to be of first order with respect to its concentration.
Giménez et al. report similar observations for aqueous phase phenol removal using the SPCD process (Jaime Giménez, David Curcó, and Pilar Marco, Reactor modelling in the photocatalytic oxidation of wastewater, Water Science and Technology 35 (1997), pp. 207-213—incorporated herein by reference in its entirety).
Dias and Azevedo also report SPCD initiated removal of three commercially used acid dyes from the aqueous phase (M. G. Dias and E. B. Azevedo, Photocatalytic Decolorization of Commercial Acid Dyes using Solar Irradiation, Water Air Soil Pollut. 204 (2009), pp. 79-87—incorporated herein by reference in its entirety). Though direct photolysis of respective wastewater sample was effective only for one pollutant, the use of TiO2 mediated solar PCD technology caused removal of all dyes with acceptable reaction rates. The reaction rates for the three studied dyes were in the following order: Acid Red 51>Acid Yellow 23>Acid Blue 9. More than 99% mineralization was also noted within 120 min of reaction time.
Huang report notable silver ions removal from the aqueous phase using the SPCD process (Min Huang, Erwin Tso, Abhaya K. Datye, Michael R. Prairie, and Bertha M. Stange, Removal of Silver in Photographic Processing Waste by TiO2-Based Photocatalysis, Environmental Science & Technology 30 (1996), pp. 3084-3088—incorporated herein by reference in its entirety).
Jiménez et al. noted about 94% removal of a widely used surfactant, i.e., sodium dodecylbenzene sulfonate (DBSNa), using the solar PCD process. The use of an additional oxidant, i.e., H2O2, during the PCD process, caused complete degradation of DBSNa.
Kumara et al. also report complete removal of phenol and methyl violet from aqueous phase using the solar irradiated PCD process (G. R. R. A. Kumara, F. M. Sultanbawa, V. P. S. Perera, I. R. M. Kottegoda, and K. Tennakone, Continuous flow photochemical reactor for solar decontamination of water using immobilized TiO2," Solar Energy Materials and Solar Cells 58 (1999), pp. 167-171—incorporated herein by reference in its entirety). However phenol degradation was noted to be faster than methyl violet. The authors also report complete removal of reaction intermediates as well.
Kuo and Ho investigated solar PCD of methylene blue contaiminated water (W. S. Kuo and P. H. Ho, Solar photocatalytic decolorization of methylene blue in water," Chemosphere 45 (2001), pp. 77-83—incorporated herein by reference in its entirety). The authors report that employing solar radiation (in the absence of TiO2) only up to 50% color removal transpired. Near complete color removal occurred with the addition of TiO2 to the same reactor system. The de-colorization efficiency was higher (near twice) using solar radiation than the artificial UV light source. Such a phenomenon was ascribed to higher excitation of target dye by the visible wave length portion of solar light, which was lower in the artificial UV light source.
Malato et al. report significant increase in solar initiated PCD of pentachlorophenol in presence of peroxydisulphate. Malato et al. studied large scale solar photocatalytic degradation reactors for the degradation of several aqueous phase pesticides. The authors report significant increase in the degradation and mineralization of target pollutants in the presence of peroxydisulphate. This modification is of great practical significance as higher solar PCD reaction rate using peroxydisulphate means an overall smaller reactor size and in turn reduced overall footprint requirements for real life solar PCD applications. Malato et al. noted successful removal of imidacloprid (which is a widely used insecticide in the agricultural areas of Mediterranean region) using solar PCD. The authors report about 95% substrate and TOC removal within 450 min of reaction time. Oxalate, formate and acetate were reported to be the intermediates. Malato et al. who investigated use of a pilot scale solar assisted photocatalysis for the destruction of aqueous phase cyanide noted significant target pollutant removal. Removal of high initial cyanide concentration (1000 mg/L) was also stated to be degraded completely using the solar PCD system. It was suggested that complete mineralization of cyanide would transpire with end product nitrates containing most N-initial.
Marques et al. noted successful treatment of aqueous phase atrazine and also of an olive oil industry's wastewater using the solar PCD process in the presence of sodium persulfate (P. A. S. S. Marques, M. F. Rosa, F. Mendes, M. Collares Pereira, J. Blanco, and S. Malato, Wastewater detoxification of organic and inorganic toxic compounds with solar collectors, Desalination 108 (1997), pp. 213-220—incorporated herein by reference in its entirety). Significant total organic carbon removal was also observed indicating mineralization of the said waste streams and confirming that no possible toxic reaction intermediates are left behind. Nagaveni et al. also report significant phenol removal from the aqueous phase using sunlight energized TiO2 photocatalysis process (K. Nagaveni, G. Sivalingam, M. S. Hegde, and Giridhar Madras, Photocatalytic Degradation of Organic Compounds over Combustion-Synthesized Nano-TiO2, Environmental Science & Technology 38 (2004), pp. 1600-1604—incorporated herein by reference in its entirety). Use of specific combustion TiO2 that was prepared using a special technique yielded catalyst that was very effective in removing phenol from the aqueous phase, and the results were comparable for both artificial and sun radiation experiments.
Neppolian et al. studied SPCD initiated removal of aqueous phase textile dye reactive blue 4. Using solar energy and TiO2, the target pollutant was mineralized within 24 h. The results showed that the dye molecules were completely degraded to CO2, SO2, NO3−, NH4+, and H2O. Furthermore, quick removal of reaction intermediates was observed in the presence of hydrogen peroxide during the PCD process.
Pacheco et al. investigated the wastewater flow rates (for the SPCD reactor) that yield about 95% trichloroethylene removal for different locations across the U.S (J. Pacheco, M. Prairie, and L. Yellowhorse, Photocatalytic destruction of chlorinated solvents with solar energy (1990)—incorporated herein by reference in its entirety). It was noted that states such as New Mexico and Texas that receive higher amount of solar energy yield highest flow rates. Furthermore at any given location significantly higher wastewater flow was processed during the months of June and July as compared to the yearly-average flow rates. The study also showed highest trichloroethylene removal during noon time for different seasons (because of higher light intensity received at that time). These trends are consistent with the artificial UV light PCD findings.
For example Wei and Wan who studied the PCD of phenol report much lower phenol removal at low light intensities (Io) whereas with an increase in the light intensity from 30% to 77% (of maximum light intensity) a sharp increase in phenol removal was observed (Tsong Yang Wei and Chi Chao Wan, Heterogeneous photocatalytic oxidation of phenol with titanium dioxide powders, Industrial & Engineering Chemistry Research 30 (1991), pp. 1293-1300—incorporated herein by reference in its entirety).
Peterson et al. (1991) also report that at higher light intensity values, the PCD rate would be directly proportional to the Io1/2 while at low light intensities PCD rate would be a linear function of Io (Peterson, M. W., Turner, J. A., and Nozik, A. J., Mechanistic studies of the photocatalytic behavior of TiO2 particles in a photoelectrochemical slurry cell and the relevance to photodetoxification reactions. J. Phys. Chem. 95 (1991), pp. 221-225—incorporated herein by reference in its entirety). Sichel et al. investigated water disinfection using solar irradiation and a TiO2 catalyst (C. Sichel, J. Tello, M. de Cara, and P. Fernández-Ibáñez, Effect of UV solar intensity and dose on the photocatalytic disinfection of bacteria and fungi, Catalysis Today 129 (2007), pp. 152-160—incorporated herein by reference in its entirety). The experiments were performed with different illuminated reactor surfaces, in different seasons of the year, and under changing weather conditions. The findings indicate that SPCD process initiated disinfection is more susceptible to changes in solar irradiation and transpired only at increased sun light intensities.
Villaneuva and Martinez studied solar radiation energized photocatalytic degradation of aqueous phase acid orange 7 (AO7) (Susana Flores Villanueva and Susana Silva Martínez, TiO2-assisted degradation of acid orange 7 textile dye under solar light, Solar Energy Materials and Solar Cells 91 (2007), pp. 1492-1495—incorporated herein by reference in its entirety). The authors report approx. 85% color removal from an AO7 solution in 2 h reaction time. Faster color removal was noted at acidic pH. However the quantification of AO7 mineralization employing the chemical oxygen demand (COD) test indicated insignificant COD reduction. Nevertheless, more than 70% COD removal transpired upon use of persulphate along with TiO2 and solar radiation. Wang investigated PCD of eight commercial dyes using TiO2 assisted photocatalysis and solar irradiation (Yizhong Wang, Solar photocatalytic degradation of eight commercial dyes in TiO2 suspension, Water Research 34 (2000), 990-994—incorporated herein by reference in its entirety). The findings indicate that the target dyes could be degraded and mineralized to end products including chloride and sulfate.
Wei et al. studied disinfection of E. coli contaminated water using PCD initiated by UV-visible light with wavelength higher than 380 nm (Chang Wei, Wen Yuan Lin, Zulkarnain Zainal, Nathan E. Williams, Kai Zhu, Andrew P. Kruzic, Russell L. Smith, and Krishnan Rajeshwar, Bactericidal Activity of TiO2 Photocatalyst in Aqueous Media: Toward a Solar-Assisted Water Disinfection System, Environmental Science & Technology 28 (1994), pp. 934-938—incorporated herein by reference in its entirety). The authors report significant bacterial kill with the reaction rate following first order kinetics. The kinetic analysis indicated a pseudo first order kinetics with respect to the initial concentration of methylene blue as per the Langmuir-Hinshelwood model. The total organic carbon (TOC) removal showed two distinct regions, i.e., an initial pseudo first order kinetics that was noted till full color removal was followed by a slower TOC removal.
Furthermore continuous supply of oxygen gas during the SPCD process did not show any significant effect on the overall process efficiency as compared to an 'open to air' study. Zhang et al. studied removal of methylene blue using the solar PCD process (Tianyong Zhang, Toshiyu ki Oyama, Satoshi Horikoshi, Hisao Hidaka, Jincai Zhao, and Nick Serpone, Photocatalyzed N-demethylation and degradation of methylene blue in titania dispersions exposed to concentrated sunlight, Solar Energy Materials and Solar Cells 73 (2002), pp. 287-303—incorporated herein by reference in its entirety). The authors observed notable removal of target pollutant under a varying set of conditions.
It is evident from the above that the removal of selenite and selenate using UV-lamp energized pure TiO2 photocatalysis along with hole scavenger EDTA has not been studied. Furthermore use of solar energized TiO2 photocatalytic degradation (SPCD) process to treat wastewater streams containing selenite and selenate species, has also not been explored. Hence the main goal of this present disclosure is to study removal of selenite and selenate species using TiO2 assisted advanced oxidation process using both UV-lamp and solar energy as the light energy source.

Removal of aqueous phase selenite and selenate using artifical and solar radiation energized photocatalysis

KING FHAD UNIVERSITY OF PETROLEUM AND MINERALS

KING ABDULAZIZ CITY FOR SCIENCE AND TECHNOLOGY


In a network including multiple nodes communicating on a channel using CSMA protocol, where each node accesses the channel by occupying at least one time slot in a contention interval, the invention includes transmitting and receiving, in a node, messages on the channel during a first time interval. The invention counts, in the node, at least one of the transmitted and received messages during the first time interval. The invention determines, in the node, a channel occupancy during the first time interval, after counting the messages, and then adaptively adjusts, in the node, the contention interval based on the channel occupancy.

Nodes in a CSMA network do not have a priority sequence for communicating with each other. Instead, any node may transmit at any time with the same priority as any other node in the network. Since nodes may attempt to transmit packets at the same time, the packets may interfere with each other, resulting in collisions. As nodes attempt a retransmission, after detecting a collision, system load in the network is typically increased.
Each node using CSMA protocol measures time from a last activity on a shared channel in equal time slots of a contention interval. A transmitting node in the network generates a random number, then counts a corresponding number of time slots until the random number is reached. At that point, the node may attempt to occupy the channel and other nodes may suspend their count until the channel is free again. If two nodes generate the same random number, by chance, and consequently collide, each then may generate a new random number and start counting time slots from zero in the next contention interval.
In a CSMA based network, nodes sense the channel before transmitting a data packet to another node. In a CSMA with collision detection (CSMA/CD) based network, nodes detect collision before transmitting, and stop transmitting if noise is sensed in the channel. In a CSMA with collision avoidance (CSMA/CA) based network, nodes listen to any activity and reserve a space in the channel to avoid collision.
To reduce the occurrence of collisions in networks, channel reservation may be deployed. Typically, reservation involves two-way communications between a transmitting node and a receiving node. When a data packet arrives from an upper layer (for example an Internet communications application), the transmitting node first reserves channel space for the transmission of the data packet. If the transmitting node detects that channel space is available, the node schedules transmission of a request-to-send (RTS) packet to a receiving node, after a generated random interval is reached. In doing so, the transmitting node informs the receiving node of the pending data packet and allows the receiving node to determine if the transmitting node may transmit the data packet over the available channel space. If the receiving node senses that channel space is available, a clear-to-send (CTS) packet is returned to the transmitting node and the channel space is reserved. After receiving the CTS packet, the transmitting node transmits the data packet over the reserved channel. By allowing the receiving node to determine whether the transmitting node may transmit the data packet, the probability of collision due to hidden nodes is reduced. In addition, collisions of multiple RTS packets, simultaneously transmitted over the channel by neighboring nodes, may also be reduced.
In general, the random delay, in number of time slots of a contention interval, is uniformly selected from a range of one time slot up to a maximum number of time slots in the contention interval, where the length of the contention interval is predetermined.
Because access rate of a node is fixed by the initial predetermined CI length, channel access rate (CAR) in the network cannot be adjusted, when more nodes than initially expected start to content for limited channel resources. In an IEEE 802.11 protocol standard, the CI length may be temporarily lengthened to lessen channel congestion at the expense of higher channel access rate. IEEE 802.11 protocol resets the CI length to its initial predetermined value, after a channel access attempt is successful. Knowledge of a prior successful channel access is not utilized in a subsequent channel access attempt. As a result, performance of the IEEE 802.11 protocol is limited.
What is needed is a system and method of controlling the CAR in a communications network by adaptively adjusting the length of the CI based on previous knowledge of traffic conditions or channel occupancy conditions in the network. This invention addresses this need.

Adaptive channel access for carrier sense multiple access based systems


A laser imaging apparatus, such as a storage phosphor reader, which converts a latent x-ray image stored in a storage phosphor into an x-ray image signal. Diagnostic routines for the storage phosphor reader are controlled by means of a touch screen monitor which displays a diagnostic screen having a plurality of selectable buttons.

In a storage phosphor imaging system as described in U.S. Pat. No. Reissue 31,847, reissued Mar. 12, 1985, to Luckey, a storage phosphor is exposed to an x-ray image of an object, such as the body part of a patient, to record a latent x-ray image in the storage phosphor. The latent x-ray image is read out by stimulating the storage phosphor with relatively long wavelength stimulating radiation such as red or infrared light produced by a helium neon gas laser or diode laser. Upon stimulation, the storage phosphor releases emitted radiation of an intermediate wavelength, such as blue light, in proportion to the quantity of x-rays that were received. To produce a signal useful in electronic image processing the storage phosphor is scanned in a raster pattern by a laser beam deflected by an oscillating or rotating scanning mirror or hologon. The emitted radiation form the storage phosphor is reflected by a mirror light collector and detected by a photodetector such as a photomultiplier to produce an electronic image signal. Typically the storage phosphor is translated in a page scan direction past the laser beam which is repeatedly deflected in a line scan direction perpendicular to the page scan motion of the storage phosphor to form a scanning raster pattern of a matrix of pixels.
As with all radiographic equipment, storage phosphor readers require periodic maintenance to correct equipment failure and to prolong the reader's operating life. Because the storage phosphor reader is not being used during maintenance periods, decreased productivity and reduced billable procedures results.
There is thus a problem in keeping maintenance time and cost to a minimum in order to increase productivity and billable procedures of a storage phosphor reader.


The present invention is directed to a display device that overcomes the limitation on tact time, and the defective phenomenon attributed to the generation of bubbles, pasting and visual irregularities at the time of laminating a film to a display panel. A polarizer is positioned in parallel to the vicinity of a main surface of a liquid crystal cell by holding two portions of the polarizer at suction stages. A portion of the polarizer is pushed and brought into contact with the main surface of the liquid crystal cell. From the portion of the polarizer, the polarizer is pushed to the main surface toward one end of the main surface along a first direction thereof. The polarizer is pushed to the main surface of the liquid crystal cell toward another end of the main surface in the first direction so as to laminate the polarizer to the main surface.

The present invention relates to a manufacturing method and a manufacturing apparatus of a display device, and more particularly to a film lamination method and a film lamination apparatus which can realize an operation to laminate a soft film to a main surface of a display panel having a hard planer display screen with high accuracy and high efficiency.
As a conventional lamination method and lamination apparatus which laminates a film-like member to a main surface of a display panel, for example, which constitutes a member to be laminated, there has been known a method which laminates a polarizer film cut in a lamination step to a liquid crystal cell in a liquid crystal display device as described in patent document 1 (Japanese Patent Laid-Open No. 161935/2003).
In this lamination method, first of all, the polarizer film which is cut in a cutting step is transported to a position above the liquid crystal cell using a lamination head provided with a laminating roller, and the lamination head is lowered above the liquid crystal cell in a state that a side of the lamination head on which the laminating roller is mounted is inclined downwardly.
Next, at a point of time that one end of the polarizer film to which the laminating roller is pushed is brought into contact with one end of the liquid crystal cell having the substantially same shape as the polarizer film, the lowering of the laminating roller is stopped and, thereafter, the laminating roller which is brought into contact with the liquid crystal cell is rolled so as to laminate the polarizer film over the entire surface of the liquid crystal cell sequentially from one end to another end on the opposite side of the liquid crystal cell whereby the polarizer film is laminated to the entire surface of the liquid crystal cell. It has been generally known that this method is the most popular method as the method and the apparatus for laminating a film member to a member to be laminated.
Further, there has been also known a lamination method and a lamination apparatus which adopt a mode in which a liquid crystal cell is positioned above and a polarizer film is positioned below. However, basically, this mode is substantially equal to the mode described in patent literature 1 in which one end of the polarizer film is laminated to one end of the liquid crystal cell and the polarizer film is sequentially laminated to another end on the opposite side.
As known examples which describe the similar constitutions, patent document 2 (Japanese Patent Laid-Open Hei06-347779), patent document 3 (Japanese Patent Laid-Open Hei06-308444), patent document 4 (Japanese Patent Laid-Open Hei05-5878) and the like are named.
Further, in patent document 5 (Japanese Patent Laid-Open No. 204304/2000) and patent document 6 (Japanese Patent Laid-Open No. 182031/2002), embodiments in which a laminating roller is constituted of a semi-cylindrical member are respectively described. In the method described in these patent document 5 and patent document 6, one end of the polarizer film is laminated to one end of the liquid crystal cell using one end of the semi-cylindrical member and, thereafter, the polarizer film is rolled on the liquid crystal cell along a cylindrical curved surface of the semi-cylindrical member and hence, the polarizer film is sequentially laminated to the liquid crystal cell. From a viewpoint that the polarizer film is laminated to the entire surface of the liquid crystal cell from one end of the liquid crystal cell sequentially, these methods are substantially equal to the method and apparatus described in patent document 1 in which one end of the polarizer film is laminated to one end of the liquid crystal cell and, then, the lamination is sequentially performed toward another end on the opposite side. Here, with respect to this type of prior art, patent document 7 (Japanese Patent Laid-Open Hei08-282906) is named.

Manufacturing method and manufacturing apparatus of display device


A method of unlocking a compartment such as a drawer in a desk where a telephone is provided on the desk, the telephone being of the type where a series of frequency tones are generated for dialing a number. The user places the handset of the telephone near a microphone receiver and dials a preset sequence of numbers on the telephone. The sound output from the handset is received by the microphone receiver, decoded and compared in memory with a preset code and if valid the lock is released to allow the drawer to be opened.

This invention relates to electronic locking devices. In particular the invention relates to a simple device and method for locking drawers, doors or other closable compartments in furniture such as office desks. Modern telephones which are connected to electronic switching exchanges produce a tone whose frequency depends upon the number dialed. When dialing a number in this way a series of tones are supplied along the telephone line and the tones are reproduced by the ear piece of the telephone. The frequencies of the tones produced are of known internationally accepted values.


Valve comprising a valve body having an upstream conduit for the inflow of a fluid and a downstream conduit for the outflow of a fluid, said conduits being substantially aligned along a longitudinal axis (X-X), a rotative ball controlling the fluid passage and having a cavity with axis perpendicular to its rotating axis (Y-Y), a first upstream seat operating in conjunction with said upstream conduit and said rotative ball, a first downstream seat operating in conjunction with said downstream conduit and said rotative ball, a second downstream seat axially arranged between said first downstream seat and said downstream conduit, and an intermediate element axially arranged between said first downstream seat and said second downstream seat and axially moveable between said first downstream seat and said second downstream seat.

Ball valves generally comprise a valve body that can be coupled to line pipes through an upstream conduit for the inflow of fluid and a downstream conduit for the outflow of fluid, a rotative ball for controlling the flow of fluid with cavity, the latter being coaxial to the direction of flow in the open position and transversal to the direction of flow in the closed position, and wherein the seal between the ball and the conduits is made by means of an upstream seat and a downstream seat interposed between the ball and the valve body.
The aforementioned valves generally have the following types of configurations: single-piston effect (SPE-SPE), double-piston effect (DPE-DPE), combined (SPE-DPE).
In the SPE configuration with the valve closed, the seats and their seals are shaped in such a way that, whenever the pressure of the fluid comes from upstream (or downstream), the resulting pressure keeps the seats pushed against the ball, ensuring the seal. Otherwise, if the fluid pressure acts from the inside of the cavity, the resulting pressure force pushes the seats towards the valve body conduits allowing the self-release of overpressures in the line.
In DPE configuration, with valve closed, the seats and the relative seals are shaped in such a way that, whenever the pressure of the fluid comes from upstream (or downstream) or acts from inside the ball, the resulting pressure force always pushes the seats towards the ball. Any overpressures inside the ball cavity are managed by appropriate release valves. The DPE configuration allows an additional seal in case of breakage of one of the two seats avoiding the fluid flowing onto the line.
In the SPE-DPE combined configuration, the upstream SPE seat ensures self-release, while the downstream DPE seat acts as a double barrier in the event of damage to the upstream seat. This configuration provides for a preferred direction of installation with the SPE seat facing upstream.
In the presence of corrosive fluids, it is normal to use mono-directional seal lips made up of elastic materials energized by springs in the seats. In particular, such seals are generally made up of high performance polymers, e.g., filled Polytetrafluoroethylene (PTFE) liners, ketone ether polyether (PEEK) additives and Nickel-Chromium-Cobalt (NiCrCo) alloy springs.
It is well known that in high or very high pressure and/or temperature applications (e.g., pressures ANSI 2500=450 bar−API 10000/15000=690/1035 bar−Tmax=200/210° C.), one-way seal lips, when used in pairs (e.g., in the so-called back-to-back configuration), undergo mechanical loads such as to reach, with the passing of time, a permanent deformation of the seal itself which prevents its correct operation.
WO 2013/066187 A1, for example, has proposed to solve the problem of permanent deformations of the PEEK/PTFE seal lips by means of a movable intermediate element placed between two seals. Although this solution permits extending the working life of the seal lips, such configuration nonetheless has the drawback of necessarily having to shape the valve body following the conformation of the intermediate element which translates into an increase in overall production costs to reach a perfect coupling between seat, intermediate element and valve body.
From the foregoing, the need emerges to have a valve that can be altogether made in a simpler and faster way, keeping production costs low without negatively affecting the mechanical and sealing characteristics of the valve itself.


A power supplying device performs both of a suppression of EMI noise and a reduction in an output voltage. In the power supply device, a switching control device that controls a switching element according to a pulse control signal includes a PPM circuit that modulates a pulse position; a PWM circuit that modulates a pulse width; and a pulse generator circuit that generates a pulse modulated by the PPM circuit and the PWM circuit. When a pulse interval of the pulse modulated in the pulse position by the PPM circuit is sparser than the pulse interval of the pulse before the modulation, the PWM circuit lengthens the pulse width. On the contrary, when the pulse interval of the pulse modulated in the pulse position by the PPM circuit is denser than the pulse interval of the pulse before the modulation, the PWM circuit shortens the pulse width.

A switching power supply is high in power conversion efficiency, smaller in size and lighter in weight than a power capacity, and low in the costs, and therefore has been widely employed from a small-capacity power supply to a large-capacity power supply. There have been known switching power supplies such as an AC-DC converter that converts an AC power from an AC power supply into a DC power supply, a DC-DC converter that steps down or up a voltage of the DC power to obtain another DC power, and a DC-AC converter that converts the DC power into the AC power.
The switching power supply is required to meet an electro-magnetic compatibility (EMC). The switching power supply causes intense electro-magnetic interference (EMI) to be generated with the switching operation, and therefore may incur drawbacks such as malfunction or breakdown of another device as a noise generator source. Accordingly, noise suppression is strongly required.
For example, WO2009/123054 discloses a technology in which an asynchronous modulation processor and a pulse position modulator are disposed downstream of a pulse width modulation processor, the asynchronous modulation processor or the pulse position modulator is selected at random to diffuse a frequency spectrum of the noise. Also, Japanese Unexamined Patent Application Publication No. 2006-288103 discloses a method in which three different intervals are provided between the respective rising edges of drive pulses of a power switching element to diffuse a switching frequency.

Power supply device with switching control device controlling switching based on pulse control signal


In an optical system measuring sample characteristics, by reducing the amount of ambient absorbing gas or gases and moisture present in at least a portion of the illumination and detection paths experienced by vacuum ultraviolet (VUV) radiation used in the measurement process, the attenuation of such wavelength components can be reduced. Such reduction can be accomplished by a process without requiring the evacuation of all gases and moisture from the measurement system. In one embodiment, the reduction can be accomplished by displacing at least some of the absorbing gas(es) and moisture present in at least a portion of the measuring paths so as to reduce the attenuation of VUV radiation. In this manner, the sample does not need to be placed in a vacuum, thereby enhancing system throughput.

This invention relates in general to optical systems for measuring characteristics of a sample, and in particular to such system using radiation that contains a vacuum ultraviolet wavelength component.
For a number of industrial applications, it is useful to determine the surface metrology of samples such as thicknesses of thin films, their refractive indices and the profile parameters of surface features such as gratings on semiconductor wafers. These characteristics may be determined by a number of techniques. Among the better known non-destructive testing techniques are those of spectroreflectometry, spectroscopic ellipsometry and scatterometry.
With the shrinking of semiconductor devices to smaller and smaller geometries, the size of surface features such as gratings has also been continually reduced. For this reason, it is desirable to improve the sensitivity of instruments for measuring the metrology of samples.
In other industrial applications, it is useful to inspect samples to detect the presence of anomalies such as particles and surface and subsurface defects, such as anomalies associated with semiconductor wafers. To detect such anomalies, the sample surface is illuminated by means of electromagnetic radiation, and the radiation scattered or reflected by the sample surface is detected to determine the presence and classification of anomalies.
The size of semiconductor devices on silicon wafers has been continually reduced. The shrinking of semiconductor devices to smaller and smaller sizes has imposed much more stringent requirements on the sensitivity of wafer inspection instruments which are called upon to detect contaminant particles, pattern defects as well as defects of the surfaces that are small compared to the size of the semiconductor devices. At the time of the filing of this application, design rule of devices down to the order of 0.1 microns or below has been called for.
One approach to improve the sensitivity of metrology measurements and of anomaly inspection and detection is to employ electromagnetic radiation of shorter wavelengths such as ultraviolet wavelengths in the range of 140-180 nanometers. Ultraviolet light in this wavelength range is absorbed by oxygen and water molecules which are generally present in an ambient environment. As such, these short wavelengths do not propagate in air over an appreciable distance. For this reason, in order for radiation in this wavelength range to be used for measurements, measurements using such radiation take place in a vacuum or in purged gas such as nitrogen or argon. The ultraviolet light in this wavelength range is referred to as vacuum ultraviolet (referred to in this application as "VUV") radiation. Vacuum or fully purged gas measurement systems, however, are expensive to build. Furthermore, since the sample that is measured is also placed in the vacuum or purged gas, such systems typically have low throughput and are not suitable in manufacturing monitoring.
It is therefore desirable to provide measurement systems that can be used to measure sample characteristics using VUV radiation while avoiding the undesirable characteristics of vacuum systems.

Optical system for measuring samples using short wavelength radiation


Thus, the present invention provides compounds of formula (I) The present invention further provides the use of a compound of formula (I) for the manufacture of a medicament for the treatment of a neurological disorder. The present invention further provides the use of a compound of formula (I) for the manufacture of a medicament for the treatment of pain or migraine

U.S. Pat. No. 5,670,516 discloses that certain decahydroisoquinoline derivatives are AMPA receptor antagonists, and as such are useful in the treatment of many different conditions, including pain and migraine. In addition, WO 01/02367 A3, published Jan. 11, 2001, discloses diester prodrug forms of the selective GluR5 antagonist 3S,4aR,6S,8aR-6-(((4-carboxy)phenyl)methyl)-1,2,3,4,4a,5,6,7,8,8a-decahydroisoquinoline-3-carboxylic acid.
It is an object of the present invention to provide monoesters of (3S,4aR,6R,8aR)-6-[2-(1(2)H-tetrazole-5-yl)ethyl-1,2,3,4,4a,5,6,7,8,8a-decahydroisoquinoline-3-carboxylic acid which provide improved bioavailability of the parent monoacid in a patient. In addition, it is an object of the present invention to provide monoesters of (3S,4aR,6R,8aR)-6-[2-(1(2)H-tetrazole-5-yl)ethyl-1,2,3,4,4a,5,6,7,8,8a-decahydroisoquinoline-3-carboxylic acid which are substantially converted to the parent monoacid in the patient.

Ester derivatives of a decahydroisoquinoline-3-carboxylic acid as analgestics


Exemplary embodiments for reconfiguring a storage system comprise receiving user requirement information for a storage device and automatically generating feature settings for the storage device from the user requirement information and a device profile for the storage device; and using the feature settings to automatically reconfigure the storage device into one or more logical devices having independent behavioral characteristics. Further exemplary embodiments comprise receiving feedback from the storage device regarding runtime performance data of at least one of the storage device and the logical devices; and responsive to a determination that the runtime performance data do not satisfy the user requirement information, dynamically adjusting configuration of the one or more logical devices to meet the user requirement information.

Modern storage systems typically include multiple standalone storage devices that are passive and whose performance characteristics are fixed in general once manufacturing is complete. A processor (e.g., RAID controller) executing software (firmware) is necessary to add intelligence to make the collection of unintelligent storage devices work as a unit. Because storage devices, such as solid state drives (SSDs), may be also controlled through the software or firmware, efforts have been made to control operating characteristics of a solid state drive according to the use environment.
The traditional approaches for satisfying user qualification tests require a manufacturer to provide last minute engineering processes to customize the storage devices for each customer. Customers typically wish to recalibrate their software systems whenever new models of storage devices are adopted because the characteristics of the storage devices are widely heterogeneous. However, the assumptions for one storage device are often not valid with another device. Consequently, traditional customization approaches are not sustainable in part because the manufacturer's engineering cost increases with the number of storage devices and customers requiring customization.
Therefore, a framework that enables an easy reconfiguration of storage systems on the behalf of customers is crucial. For instance, solid state disk (SSD) optimization software, such as Magician™ by Samsung, tunes performance of SSDs for a customer's system. However, customers have very limited optimization options, the optimization metrics are device-oriented in contrast to user-oriented, and the optimization is not controlled or quantifiable. In addition, storage device characteristics can change over time due to the degradation of the storage media such as wearing and fatigue. This can violate the initial assumption that the customer had, which cannot be perceived easily until malfunctions happen at the user level.
Another type of reconfigurable storage device process allows a customer to select individual features to configure a storage device. In this approach, instead of adjusting a customer's system to a new storage device, a reconfigurable storage device allows the customer to adjust the storage devices to their systems, which simplifies the maintenance and upgrade process.
Although reconfigurable storage devices can provide more flexibility in performance optimization and allow the customers to do customization, several challenges remain. One challenge is that the recalibration process constitutes a combinatory problem whose complexity increases exponentially with the number of features of the storage device to customize. In other words, current approaches do not provide systematic configuration method for feature selection. For example, if a customer changes the value of three features, it may be difficult for the customer to determine what effect the combination of features will be on the performance of the storage device.
A related challenge is that the selection of features by the customer is accomplished through a software user interface in which the customer selects the features manually. Manual selection of features without a systematic configuration method or performance guideline results is essentially a trial and error process.
Finally, the conventional reconfiguration process does not address the effects of storage device characteristics changing over time due to the degradation of the storage media. Such changes can render the original selection of features for a particular use environment no longer valid.
Accordingly, the trend of software-defined storage (SDS) in which storage resources required by an application can be defined by software and provisioned automatically requires an improved reconfigurable storage process that is more flexible.


A tractor for hauling concrete and similar materials at a construction site. The tractor includes an engine powering two pumps connected in series. The two pumps providing hydraulic pressure to: independently power each of a plurality of wheels; to rotate at least one of the wheels to provide steering to the tractor; to raise and lower a bucket; and to release and close a latch for a gate connected to the bucket.

1. Field of the Invention
This invention relates generally to a tractor for hauling materials or cargo, including concrete, at a construction site and, more particularly, to a tractor utilizing hydraulics.
2. Discussion of Related Art
Various tractors for hauling cargo at a construction site are known. For example the Scoot-Crete® power buggy is a device designed for hauling concrete at construction sites. The Scoot-Crete® power buggy is a two-wheel drive cart with a bucket. These carts support the cargo over the two drive wheels but, because the cargo is often very heavy, these carts can sink into soft ground and bottom out on the frame of the cart. Such characteristics may cause the drive wheels to lose traction and spin in the soft ground.