Big Chemical Encyclopedia

Chemical substances, components, reactions, process design ...

Articles Figures Tables About

Water, theories equation

Several refinements of our experiments could test these theories further. By measuring etch pit densities as well as pit dimensions on sequentially-etched crystals, nucleation rate data and pit growth data could be collected, yielding information about the rate-limiting steps and mechanisms of dissolution. In addition, since the critical concentration is extremely dependent on surface energy of the crystal-water interface (Equation 4), careful measurement of Ccrit yields a precise measurement of Y. Our data indicates an interfacial energy of 280 + 90 mjm- for Arkansas quartz at 300°C, which compares well with Parks value of 360 mJm for 25°C (10). Similar experiments on other minerals could provide essential surface energy data. [Pg.646]

Membrane Water Content. Whether the dilute solution or concentrated solution theory equations are used to model the membrane system, functional forms for the transport parameters and the concentration of water are needed. The properties are functions of temperature and the water content, In the models, empirical fits are... [Pg.454]

This ability to interact strongly with positively and negatively charged ions is consistent with water s nnique amphoteric (acid-base) properties, and is why it is fundamental to the Bronsted acid-base theory (equations 4 and 5). [Pg.3454]

Duh DM, Perera DN, Haymet ADJ (1995) Structure and properties of the CFl central force model of water - integral-equation theory. J Chem Phys 102(9) 3736-3746... [Pg.612]

If the water is deeper than 200 m, the linear long wave equation should be applied. For the region shallower than 200 m, the shallow water theory with a term for bottom friction included should be used. This shallow water theory includes the first order approximation of the amplitude dependent dispersion. Under special conditions, the term for frequency dependent dispersion should be included. If the purpose of the simulation is to determine the runup height, the equations of higher order approximations are not necessary. [Pg.58]

Figure 31.11 For benzene partitioning from water into different hydrocarbons, the partition coefficient depends on the oil chain length. The chain-length dependence is treated well by the Flory-Huggins theory, Equation (31.31). ( octane, decane, A dodecane, tetradecane, o hexadecane.) Source LR DeYoung and KA Dill, J Phys Chem 94, 801-809 (1990). Figure 31.11 For benzene partitioning from water into different hydrocarbons, the partition coefficient depends on the oil chain length. The chain-length dependence is treated well by the Flory-Huggins theory, Equation (31.31). ( octane, decane, A dodecane, tetradecane, o hexadecane.) Source LR DeYoung and KA Dill, J Phys Chem 94, 801-809 (1990).
Experimental observation of such a trend in lEJ would be a strong indication that the threshold phenomenon is real. Fig. 76 shows the results of nitrogen adsorption on the above-mentioned oxides most of which were reported by Fuller and Thompson [17]. (H2O is for water pre-covered oxides and CO is for partially oxidized carbon.) The value for E of oxides is plotted as a function of the enthalpy of their formation. Since the threshold pressures for some of the oxides are too low to be measured directly, Xc values are obtained from the % theory equation. It is apparent that the correlation does exist as predicted. Although not claimed, due to the question of stoichiometry to be used for the cleaved solid surface, this figure shows a linear relationship between the energies of the threshold and the enthalpies of formations. For the intersection at = 0, the value for E should be... [Pg.142]

Equations are derived below that allow calculation of the water/solvent injection ratio required for equal water/solvent velocities. The model is for ID flow and is based on fractional-flow theory. Equations and graphical solutions are presented to descaibe WAG injection for both secondaiy and tertiary recovery conditions. Walsh 4 gives a more comprehensive treatment using fractional-flow theory. [Pg.75]

For example, for molecular acids in water the equation reduces to an expression equivalent to that of the water theory ... [Pg.8]

Various equations of state have been developed to treat association ia supercritical fluids. Two of the most often used are the statistical association fluid theory (SAET) (60,61) and the lattice fluid hydrogen bonding model (LEHB) (62). These models iaclude parameters that describe the enthalpy and entropy of association. The most detailed description of association ia supercritical water has been obtained usiag molecular dynamics and Monte Carlo computer simulations (63), but this requires much larger amounts of computer time (64—66). [Pg.225]

One important class of integral equation theories is based on the reference interaction site model (RISM) proposed by Chandler [77]. These RISM theories have been used to smdy the confonnation of small peptides in liquid water [78-80]. However, the approach is not appropriate for large molecular solutes such as proteins and nucleic acids. Because RISM is based on a reduction to site-site, solute-solvent radially symmetrical distribution functions, there is a loss of infonnation about the tliree-dimensional spatial organization of the solvent density around a macromolecular solute of irregular shape. To circumvent this limitation, extensions of RISM-like theories for tliree-dimensional space (3d-RISM) have been proposed [81,82],... [Pg.144]

Chapter 3 of Volume 1 discusses many of the basic properties of gas and methods presented for calculating them. Chapter 6 of Volume 1 contains a brief discussion of heat transfer and an equation to estimate the heat required to change the temperature of a liquid. This chapter discusses heat transfer theory in more detail. The concepts discussed in this chapter can be used to predict more accurately the required heat duty for oil treating, as well as to size heat exchangers for oil and water. [Pg.7]

Because of the difficulties in determining x, the thickness of the film between the two vapor pressures, an overall transfer coefficient is introduced. Based on the two film theory, the overall transfer coefficient is used. In the case of water evaporation, the gas film is the controlling mechanism and the resulting equation is... [Pg.1359]

The principal cathodic reaction on the upper surface of the membrane is the reduction of Cu " that is formed by the reaction of Cu with dissolved oxygen in the water these Cu ions are provided partly from the diffusion through the pores in the oxide membrane from within the pit and partly from those produced by cathodic reduction (equation 1.154). Lucey s theory thus rejects the conventional large cathode small anode relationship that is invoked to explain localised attack, and this concept of an electronically conducting membrane has also been used by Evans to explain localised attack on steel due to a discontinuous film of magnetite. [Pg.187]

Perrin model and the Johansson and Elvingston model fall above the experimental data. Also shown in this figure is the prediction from the Stokes-Einstein-Smoluchowski expression, whereby the Stokes-Einstein expression is modified with the inclusion of the Ein-stein-Smoluchowski expression for the effect of solute on viscosity. Penke et al. [290] found that the Mackie-Meares equation fit the water diffusion data however, upon consideration of water interactions with the polymer gel, through measurements of longitudinal relaxation, adsorption interactions incorporated within the volume averaging theory also well described the experimental results. The volume averaging theory had the advantage that it could describe the effect of Bis on the relaxation within the same framework as the description of the diffusion coefficient. [Pg.584]

Equations and can be derived from our simple molecular picture and kinetic molecular theory. The derivation is independent of the nature of solute and solvent, so the equations are valid for other solvents besides water, except that Kf and have... [Pg.861]

Although the protonic theory is not confined to aqueous solutions, it does not cover aprotic solvents. The solvent system theory predates that of Bronsted-Lowry and represents an extension of the Arrhenius theory to solvents other than water. It may be represented by the defining equation ... [Pg.16]


See other pages where Water, theories equation is mentioned: [Pg.263]    [Pg.263]    [Pg.291]    [Pg.900]    [Pg.14]    [Pg.123]    [Pg.73]    [Pg.164]    [Pg.272]    [Pg.244]    [Pg.42]    [Pg.562]    [Pg.205]    [Pg.227]    [Pg.488]    [Pg.503]    [Pg.1414]    [Pg.145]    [Pg.473]    [Pg.102]    [Pg.644]    [Pg.321]    [Pg.136]    [Pg.766]    [Pg.34]    [Pg.9]    [Pg.604]    [Pg.141]    [Pg.16]    [Pg.26]    [Pg.425]    [Pg.217]   
See also in sourсe #XX -- [ Pg.266 , Pg.267 , Pg.268 ]




SEARCH



Water equations

Water theories

© 2024 chempedia.info