Experimental values of the dielectric constant of water suggest that, for temperatures greater than 400 K, the integral in the Kirkwood dielectric-constant equation, which involves the intermolecular potential function, is a simpler function of temperature and pressure than of temperature and density. An equation has been fitted to values of this integral calculated from experimental values of the dielectric constant for temperatures from 238.15 K to 823.15 K and to pressures of approximately 500 MPa for temperatures greater than 273 K. The equation for E thus has explicit variables T, p, P and gives a good representation of the available experimental results. The quality of representation of the experimental results has been compared to that of previous correlations of the dielectric constant. The new equation is applicable through wider regions of imlepenuent variables than the previous equations and is capable of sufficient accuracy to provide values of Debye-Hiickel limiting law slopes which are as accurate as the experimental results allow. Values of Dehye-Hiickel limiting-law slopes are tabulated.

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This paper studies a class of Poisson mixture models that includes covariates in rates. This model contains Poisson regression and independent Poisson mixtures as special cases. Estimation methods based on the EM and quasi-Newton algorithms, properties of these estimates, a model selection procedure, residual analysis, and goodness-of-fit test are discussed. A Monte Carlo study investigates implementation and model choice issues. This methodology is used to analyze seizure frequency and Ames salmonella assay data.

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A comprehensive thermodynamic model, referred to as the mixed-solvent electrolyte (MSE) model, has been applied to calculate phase equilibria, speciation, and other thermodynamic properties of selected systems that are of interest for understanding the chemistry of salt lakes and natural waters. In particular, solubilities and chemical speciation have been analyzed for various boron-containing systems, which represent an important subset of solution chemistry for such applications. The model has been shown to reproduce the speciation, solubility, and vapor–liquid equilibrium (VLE) data in the boric acid + water system over wide ranges of temperature and concentration. Specifically, solubilities have been accurately represented in the full concentration range of the B2O3 + H2O system (xB2O3 = 0~1), which includes H3BO3. The accuracy of the model has also been demonstrated by calculating solubilities in various aqueous borate systems, i.e., MnO + B2O3 + H2O (where M = Li, Na, Ca, Mg), and their mixtures with a chloride salt or an acid (i.e., LiCl, NaCl, HCl). The model predicts the effects of chemical speciation, temperature, and concentrations of various acid, base, and salt components on the formation of competing solid phases.

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