Water condition effect

Chul Kim, U. R. and van Rooyen, D., Strain rate and temperature effects on the stress corrosion cracking of Inconel 600 steam generator tubing in the (PWR) primary water conditions , Proc. 2nd Int. Conf. on Environmental Degradation of Materials in Nuclear Power Systems-VIalet Reactors, Monterey, USA, 9-12 Sept. 1985, American Nuclear Society, pp. 448-55 (1986)... 

Because thermal gradients vary considerably within boilers, a typical BW sample, which is essentially representative of average internal bulk water conditions, is unlikely to provide sufficient valid information necessary for the critical assessment of conditions at boiler surfaces. This makes fine-tune control of coordinated phosphate programs within the areas they are most needed very difficult, if not impossible, especially because caustic and saline concentrations may be much higher under deposits than in the bulk water as a result of localized effects. 

In this case water is effectively acting as a catalyst for the reaction by lowering the energy of activation. These catalytic water molecules are more likely to participate in the reaction under supercritical conditions because their high compressibility promotes the formation of solute-solvent clusters. 

Sc(OTf)3 is stable in water, and effectively activates carbonyl and related compounds as a Lewis acid in water. This is remarkable, because most Lewis acids react immediately with water rather than the substrates, and are decomposed or deactivated. It has already been found that lanthanide trifiates Ln(OTf)3 (Ln = La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu) and yttrium trifiate Y(OTf)3 are stable in water, and can act as Lewis-acid catalysts in aqueous media.46-48 They are used catalytically in many reactions and can often be recovered and reused, because they are stable under the usual water-quenching conditions. 

Duhamel et al. [118] investigated the behaviour of this (tributyltin) oxide and tributyltin chloride in saline water. The effects of salinity, pH, light, and oxygen were investigated. Debutylation due to the formation of insoluble compounds occurred under saline conditions. 

The reverse osmosis performance of the two membranes under typical brackish water conditions is shown in Figure 2 (I, reference membrane III, with bentonite). At a rejection of 85 % the flux is almost doubled (from 2000 to nearly 4000 l/m d), the effect becoming smaller when going to higher rejections. Maximum brackish water rejection of the bentonite membrane is 97 % as against 98 % for the reference membrane. 

The objective of employing organophilic bentonite is flux stabilization. In terms of the membrane compaction slope the stabilizing effect is exemplified by the following figures (brackish water conditions) reference, -0.10 bentonite-doped, -0.06. In a field test over 1300 hours on well water of 5200 ppm TDS at a pressure of 60 bar, starting with an initial flux of 1780 1/m d and 95 % rejection, a compaction slope of -0.058 was found under the same conditions the reference membrane had a compaction slope of -0.094. 

Tphe excellent catalytic activity of lanthanum exchanged faujasite zeo-A lites in reactions involving carbonium ions has been reported previously (1—10). Studies deal with isomerization (o-xylene (1), 1-methy 1-2-ethylbenzene (2)), alkylation (ethylene-benzene (3) propylene-benzene (4), propylene-toluene (5)), and cracking reactions (n-butane (5), n-hexane, n-heptane, ethylbenzene (6), cumene (7, 8, 10)). The catalytic activity of LaY zeolites is equivalent to that of HY zeolites (5 7). The stability of activity for LaY was studied after thermal treatment up to 750° C. However, discrepancies arise in the determination of the optimal temperatures of pretreatment. For the same kind of reaction (alkylation), the activity increases (4), remains constant (5), or decreases (3) with increasing temperatures. These results may be attributed to experimental conditions (5) and to differences in the nature of the active sites involved. Other factors, such as the introduction of cations (11) and rehydration treatments (6), may influence the catalytic activity. Water vapor effects are easily... 

The addition of water-soluble polymers such as polyethylene oxide (PEO) or polyvinyl alcohol (PVA) into the synthetic mixture of the C TMAX-HN03-TE0S-H20 system (n = 16 or 18 X = Br or Cl) under shear flow is found to promote uniformity and elongation of rope-like mesoporous silica. The millimeter-scaled mesoporous silica ropes are found to possess a three-level hierarchical structure. The addition of water-soluble polymer does not affect the physical properties of the silica ropes. Moreover, further hydrothermal treatment of the acid-made material under basic ammonia conditions effectively promotes reconstruction of the silica nanochannels while maintaining the rope-like morphology. As a result, a notable enhancement in both thermal and hydrothermal stability is found. 

Fatty Acid—Sarcosine Condensates. These surfactants are prepared by the reaction of fatty acid chlorides with methyl glycine sodium lauroyl sarcosinate [137-16-6] is an example of this group. They are most effective at pH 5.5—6.0 for foaming activity in soft to moderately hard water. The action of these deteigents is gready reduced under severe hard water conditions. The sarcosinates exhibit compatibility with cationic surfactants and have been suggested for use in formulation of conditioning shampoos (7). 

X. Huang, X. Wang, J. Preston, L. Bonville, H.R. Kunz, M. Perry, D. Condit, effect of water management schemes on the membrane durability in PEMFCs. ECS Trans. 16, 1697 (2008)... 

Cidu, R. and R. Biddau. 2007. Transport of trace elements under different seasonal conditions Effects on the quality of river water in a Mediterranean area. Appl. Geochem. 22 2777-2794. 

Hydrophobic zeolites, as well as the all-silica zeolites or zeolites with a very small aluminum content, possess high capacity for adsorbing organic compounds dissolved in water. Some recent studies demonstrated that hydrophobic, dealuminated zeolites adsorbed organic compounds from water as effectively as activated carbon [2,37,88,89,214], The hydrophobicity of zeolites is controlled basically by changing the Si/Al ratio in the framework by synthesis conditions and postsynthesis modification treatments [215],... 

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