Screening, of water

Abanades S, Charvin P, Flamant G, Neveu P (2006) Screening of water-splitting thermochemical cycles potentially attractive for hydrogen production by concentrated solar energy. Energy 31 2805-2822... 

Nayal, M. and Di Cera, E. (1996). Valence screening of water in protein crystals reveals potential Na binding sites. J. Mol. Biol. 256, 228-34. 

Initial screening of water samples and extracts mainly focuses on the presence of polar nonvolatile alkylphosphonic acids and nonvolatile breakdown products of nerve agents in Schedule 2 (Precursors Schedule 2.B.04, 2.B.11, 2.B.12, and 2.B.14) (10). Water samples and extracts are preferably screened without sample preparation, typically with ... 

Nerve agents hydrolyze sufficiently slowly to be analyzed by LC/MS under reversed phase conditions. Although analyses for nerve agents alone are usually performed by GC-based methods, there are scenarios, for example, screening of water samples, in which LC/MS offers a rapid alternative. LC/MS is particularly useful for combined analysis of agents and degradation products. A number of applications have recently been reported for the... 

Abanades, S., Charvin, P., Flamant, G., and Neveu, P., Screening of Water-Splitting Thermochemical Cycles Potentially Attractive for Hydrogen Production by Concentrated Solar Energy , Energy, 31, 2805-22, 2006. 

R.A.C. Lima, S.R.B. Santos, R.S. Costa, G.P.S. Marcone, R.S. Honorato, V.B. Nascimento, et al., Hardness screening of water using a flow-batch photometric system, Anal. Chim. Acta 518 (2004) 25. 

Van Hoof, F. M., et al., The Evaluation of Bacterial Biosensors for On-Line Screening of Water Pollutants , Environmental Tichnol. Lett. (1990) in press. 

MacNevin CJ, Atif F, Sayeed I, Stein DG, Liotta DC (2009) Development and screening of water-soluble analogues of progesterone and aUopregnanolone in models of brain injury. J Med Chem 52 6012-6023... 

Cappiello s research group applied micro-HPLC to the screening of water samples for pesticide contamination. With electron ionization mass spectrometric detection and the use of two microcolumns packed with a Cig silica-based stationary phase, they performed the preconcentration of water samples and successfully detected trace levels of pollutants in similar samples. They also showed that ion-interaction micro-HPLC on a Cig stationary phase with hexylamine as the ion-pair reagent and coupling to particle beam mass spectrometry could be successfully used for the analysis of herbicides ranging from acidic species such as... 

Liquid membrane anion ion-exchanger type sensors are best illustrated by the nitrate ISE (95-96). This has seen a role in the environmental screening of waters and effluents (97,) fo> nitrate, but such use has been somewhat diminished by the high sensitivity and facility for multi-ion analysis of the newer approach of ion-chromatography. 

This test method provides inexpensive field screening of water vapor. The system design is such that it may be used by nontechnical personnel, with a minimum of proper training. 

One procedure makes use of a box on whose silk screen bottom powdered desiccant has been placed, usually lithium chloride. The box is positioned 1-2 mm above the surface, and the rate of gain in weight is measured for the film-free and the film-covered surface. The rate of water uptake is reported as u = m/fA, or in g/sec cm. This is taken to be proportional to - Cd)/R, where Ch, and Cd are the concentrations of water vapor in equilibrium with water and with the desiccant, respectively, and R is the diffusional resistance across the gap between the surface and the screen. Qualitatively, R can be regarded as actually being the sum of a series of resistances corresponding to the various diffusion gradients present ... 

The calculated energy of water (-75 5860 au) is displayed at the bottom of the screen... 

After the waterwaH tubes deHver the saturated steam back into the top of the boHer dmm, moisture is separated out by a series ofbaffl.es, steam separators, and cormgated screens. The water removed drops down into the hot water contained in the steam dmm. The steam travels out through either a dry pipe, which leads to a superheater header, or a series of superheater tubes that connect directiy into the top of the steam dmm. The superheater tubes wind back into the top of the furnace and/or a hot flue-gas backpass section, next to the economizer, where heat from the combustion gases exiting the furnace superheats the steam traveling through the tubes. 

Following carbonation, the product can be further purified by screening. This screening, also used to control the maximum size of the product, is followed by dewatering (qv). Rotary vacuum filters, pressure filters, or centrifuges are used in the mechanical removal of water. Final drying is accompHshed as with natural calcium carbonate in either a rotary, spray, or flash dryer. Products having mean particle sizes from submicrometers (- O-OS fiTo) to several micrometers are available. 

The largest class of processes appHed to farm commodities are separations, which are usually based on some physical property such as density, particle size, or solubiHty. For example, the milling process for cereal grains involves size reduction (qv) foUowed by screening to yield products that have varied concentrations of starch, fiber, and protein. Milling of water slurries is practiced to obtain finer separation of starch, fiber, protein, and oil. 

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