Plant polar

Delgado, E., M.A.J. Parry, D.W. Lawlor, A.J. Keys, and H. Medrano Photosynthesis, ribulose-l,5-bisphos-phate carboxylase, and leaf characteristics of Nicotiana tabacum L. genotypes selected by survival at low carbon dioxide concentrations J. Exp. Botany 44 (1993) 1-7. Demandre, C., A. Iremolieres, A. Justin, and P. Mazliak Analysis of molecular species of plant polar lipids by high-performance and gas liquid chromatography Phytochemistry 24 (1985) 481 85. 

C. Demandre, A. Tremolieres, A.M. Justin et P. Mazliak - Analysis of molecular species of plant polar lipids by high-performance and gas-liquid chromatography. Phytochemistry, 24, 481-485 (1985). 

Naturally occurring molecular ensembles such as proteins from photosyntlietic systems (plants, algae, photosyntlietic bacteria, etc) are usually relatively rigid systems tliat contain various cliromophores and hold tliem at fixed positions and orientations relative to each otlier. That is why, despite tire numerous energy jumps between tire cliromophores, tlie resulting emitted fluorescence is polarized. The extent of tliis polarization tlius affords invaluable infonnation about tlie internal stmcture of molecular complexes. 

Pervaporation has been commercialized for two appHcations. The first and most developed is the separation of water from concentrated alcohol solutions. GFT of Neunkirchen, Germany, the leader in this field, installed their first important plant in 1982. More than 100 plants have been installed by GFT for this appHcation (90). The second appHcation is the separation of small amounts of organic solvents from contaminated water (91). In both of these apphcations, organics are separated from water. This separation is relatively easy, because organic compounds and water, due to their difference in polarity, exhibit distinct membrane permeation properties. The separation is also amenable to membrane pervaporation because the feed solutions are relatively nonaggressive and do not chemically degrade the membrane. 

Researchers at Phillips Petroleum Company developed a commercially viable process for the synthesis of PPS involving the polymerization of /)-dich1orohenzene and a sodium sulfide source in a polar organic compound at elevated temperature and pressure. This Phillips process was patented in 1967 (18). Between 1967 and 1973, Phillips built and operated a pilot plant, estabhshed market demand, and constmcted a hiU-scale commercial plant. In 1973, the world s first PPS plant came on-stream in Phillips faciUty in Borger, Texas. 

Difficulties with the Na—S system arise ia part from the ceramic nature of the alumiaa separator the specific P-alumiaa is expeasive to prepare and the material is brittie and quite fragile. Separator failure is the leading cause of early cell failure. Cell failure may also be related to performance problems caused by polarization at the sodium/soHd electrolyte iaterface. Lastiy, seal leakage can be a determiaant of cycle life. In spite of these problems, however, the safety and rehabiUty of the Na—S system has progressed to the poiat where pilot plant production of these batteries is anticipated for EV and aerospace apphcations. 

Polarization probe.s. Polarization methods other than LPR are also of use in process control and corrosion analysis, but only a few systems are offered commercially. These systems use such polarization techniques as galvanodynamic or potentiodynamic, potentiostatic or galvanostatic, potentiostaircase or galvanostaircase, or cyclic polarization methods. Some systems involving these techniques are, in fact, used regularly in processing plants. These methods are used in situ or... 

Alkyl sulphoxides occur widely in small concentrations in plant and animal tissues. No gaseous sulphoxides are known and they tend to be colourless, odourless, relatively unstable solids soluble in water, ethyl alcohol and ether. They are freely basic, and with acids form salts of the type (R2S0H) X. Because sulphoxides are highly polar their boiling points are high. Their main use is as solvents for polymerization, spinning, extractions, base-catalysed chemical reactions and for pesticides. 

Sacrificial anode systems operate without external power source. The anodes are reactive metals such as magnesium and zinc or aluminum alloys. The energy for the process is derived from the anode material. Careful design is required to match the output and lifetime of the anodes with the polarization and life-expectancy requirements of the plant. Sacrificial anode CP is used for offshore platforms, sub-sea pipelines and the inside of ballast tanks on tanker ships. 

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