Influence of water concentration

Fig. 9 Influence of water concentration on the concentration profiles of substrate and products in the telomerization of glycerol. Adapted with permission from [88]...

The Influence of Water Concentration on the Mechanical and Rheo-Optical Properties of Poly(methyl methacrylate)... 

Moore, R.S. and J.R. Flick, The Influence of Water Concentration on the Mechanical and Rheo-Optical Properties on Poly(methyl medtacrylate), in Water in Polymers, S.P. Rowland, Editor. 1980, American Chemical Society Washington, D. C. p. 555-570. 

Kuster BFM (1977) The influence of water concentration on the dehydration of D-fructose. 

Diluted samples In highly diluted samples, the activity coefficients are identical for the calibration solution and the analytical portion of the sample. The influence of water concentration and sodium binding is negligible. Accordingly, the concentration of sodium in the sample can be calculated from the concentration of the calibration solution. Thus, measurements by ISEs in diluted samples give comparable estimates of the amovmt of sodium in the... 

Tada, E.B., Guard, N., Silva, P.L., Blagoeva, I.B., El Seoud, O.A., Ruasse, M.-F. Nucleophilic reactivity of the CTACl-micelle-bound fluoride ion the influence of water concentration and ionic strength at the micellar interface. Langmuir 2003, 79(26), 10666-10672. 

However, measurements of substituent effects supported the hypothesis that the aryl cation is a key intermediate in dediazoniations, provided that they were interpreted in an appropriate way (Zollinger, 1973a Ehrenson et al., 1973 Swain et al., 1975 a). We will first consider the activation energy and then discuss the influence of substituents, as well as additional data concerning the aryl cation as a metastable intermediate (kinetic isotope effects, influence of water acitivity in hydroxy-de-di-azoniations). Finally, the cases of dediazoniation in which the rate of reaction is first-order with regard to the concentration of the nucleophile will be critically evaluated. 

Fig. 1 Scheme illustrating the influence of water discharge (y axis) and solute concentration (metals and nutrients on the x axis) on in-stream retention efficiency measured on the basis of the nutrient spiraling concept. The most remarkable Metal (M) effects on biofihns are indicated in the... 

Majumder and Bhowmick [381] have investigated the influence of the concentration of TMPTA on the surface properties of EPDM mbber, modified in the presence of EB. The surface energy of the TMPTA-modified EPDM mbber has been observed to increase as compared to the unmodified one. Table 31.4 displays the contact angles and the work of adhesion of water, for the control and the modified EPDM surfaces. 

The carbon dioxide concentration in the film can also be controlled by other physical and chemical parameters, for instance the type of catalyst (influencing the reaction rate constants) or the use of more hydrophobic resin (influencing the water concentration). 

Example 4.2. The influence of solute concentration on water structure... 

This application is designed to model the influence of various concentrations of a solute near one edge of the membrane, on the diffusion of water through the membrane. Specifically we are interested in determining whether the model reveals a difference in the flow of water out of one compartment relative to the other. It is well known that if a semipermeable membrane is impervious to a solute on one side of a membrane, a greater flow of water from the other side will occur. This is a model of the osmotic effect, the flow of water through the... 

The influence of HjOj concentration on stainless steel potential was determined by exposing a coupon to known concentrations of HjOj in aerated river water and measuring and pH. After correcting for a -60 mV/pH unit change due to slight acidification from the added HjOj, E followed the relationship ... 

Lange TR, Royals HE, Connor LL. 1993. Influence of water chemistry on mercury concentration in largemouth bass from Florida lakes. Trans Am Fish Soc 122 74-84. 

The influence of other active components, such as 1, OH, H on a semiconductor sensor, with other conditions being the same, is comparable with the influence of atomic oxygen [50]. Contribution of N and OH is proportional to their relative contents (compared to that of atomic oxygen) in the atmosphere and may become essential at altitudes lower than 60 - 70 km. The use of selective detectors excludes the influence of atomic hydrogen. Studies of adsorption of water vapours on ZnO films [50] show that their influence is negligibly small at the film temperatures below 100°C. Variations of electric conductivity of the films under the influence of water vapours and of an atomic oxygen are comparable at the ratio of their concentrations [H20]/[0] = 10" . 

The concentration of detergents in the washing liquor can also be determined by measuring their conductivity [80]. Due to the influence of water hardness and soil the accuracy is limited. 

Kornblum et al. (1963) demonstrated that O- vs. C-alkylation (24) of yS-naphthoxide ion (an ambident ion) is markedly solvent dependent. For example, the reaction with benzyl bromide conducted in dimethylformamide gave 97% O-alkylated product, whereas in water 81% C-alkylated product resulted. The difference is attributed to changes in the solvation of ambident anions. The course of the reaction is also influenced by water concentration in... 

The use of polyethers and quaternary salts as liquid-liquid and solid-liquid phase transfer catalysts has been well-documented in the literature. It has been shown that (1) the catalyst functions as a vehicle for transferring the anion of a metal salt from the aqueous or solid phase into the organic phase where reaction with an organic substrate ensues, (2) the rate of reaction is proportional to the concentration of the catalyst in the organic phase, and (3) small quantities of water have a significant effect on the catalytic process. This Communication specifically addresses the role of cyclic polyethers as phase transfer catalysts and the influence of water with regard to the location of the catalyst. 

Beltrame, P., Beltrame, P.E., and Cartini, P. Influence of feed concentration on the kinetics of biodegradation of phenol in a continuous stirred reactor, Water Res., 18(4) 403-407,1984. 

Steam is invariably present in a real exhaust gas of motor vehieles in relatively high concentration due to the fuel combustion. The influence of water vapor on catalytic performances should not be ignored when dealing with the aim to develop a practical TWCs. Cu/ZSM-5 catalysts once were regarded as suitable substitutes to precious metal catalysts for NO elimination[78], nevertheless, they are susceptible to hydrothermal dealumination leading to a permanent loss of activity[79], Perovskites have a higher hydrothermal stability than zeolites[35]. Although perovskites were expected to be potential autocatalysts in the presence of water[80], few reports related to the influence of water on the reactants adsorption, the perovskite physicochemical properties, and the catalytic performance in NO-SCR were previously documented. The H2O deactivation mechanism is also far from well established. 

Ferguson and Shah described polymerization of AA in the presence of polyCethylene oxide), PEG, having mol. weight of 1,500 and 6,000. Polymerizations were carried out in water at 55 and 74°C. Potassium persulphate was used as an initiator. Having examined the influence of template concentration on the rate of polymerization, it was found that the maximum rate appears not at equimolar ratio of monomer to template, but at much lower concentration of the template. Polymerization of AA in the presence of PEG in water at 74°C was treated by the authors as an example of the system in which the interaction between template and the monomer is rather weak. Indeed, only tern-... 

A procedure is presented for correlating the effect of non-volatile salts on the vapor-liquid equilibrium properties of binary solvents. The procedure is based on estimating the influence of salt concentration on the infinite dilution activity coefficients of both components in a pseudo-binary solution. The procedure is tested on experimental data for five different salts in methanol-water solutions. With this technique and Wilson parameters determined from the infinite dilution activity coefficients, precise estimates of bubble point temperatures and vapor phase compositions may be obtained over a range of salt and solvent compositions. 

Data have been presented for five salts in methanol-water solutions, which indicate clearly the influence of salt concentration on the observed salt effects and the Wilson parameters. 

The pH has a great influence on the enzymatic processes during mashing. Through water treatment it is possible to bring about shifts in pH whereby the transformations are decisively influenced. P-Amylase has a pH optimum at 5.4, a-amylase at 5.8, and the normal mash has a pH of about 5.4 during saccharification. The influence of the concentration of the mash is such that thin mash increases the yield of both extract and maltose (Table 9). 

Dalla Rosa, M., Pittia, P., and Nicoli, M.C. 1992. Influence of water activity on headspace concentration of volatiles over model and food systems. Ital. 1 Food Sci. 4 421-432. 

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