In this work, the results concerning to the mean activity coefficient measurements for NaCl in the (glycerol + water) system using the potentiometric method are reported. The potentiometric measurements were performed on the galvanic cells without liquid junction of the type: Ag|AgCl|NaCl (m), glycerol (wt%), H2O (1 - wt)%|Na-ISE, in various mixed solvent systems containing 0, 5, 10,...

The solubility of K2SO4 in water at 25°C was determined. Comparing the value ofthermodynamic solubility product constant, Ksp(th), (Ksp(th) = exp (-ΔGodiss RT) of the mentionedsalt to the value of concentration solubility product, Ksp(c) which is obtained from the observedsolubility, s/moL-1, Ksp(c) = 4s3, revealed a great difference. The difference can be satisfactorilyexplained using Debye- H...

The history of the relationship of biological activity to partition coefficient and related properties is briefly reviewed. The dominance of partition coefficient in quantitation of structure-activity relationships is emphasized, although the importance of other factors is also demonstrated. Various mathematical models of in vivo transport and binding are discussed; most of these involve partit...

We investigate the long time behaviour of the L-energy of solutions to wave equations with variable speed. The novelty of the approach is the combination of estimates for higher order derivatives of the coefficient with a stabilisation property. 1. Model problem We consider the Cauchy problem (1.1) utt − a (t)∆u = 0, u(0, ·) = u1 ∈ H (R), Dtu(0, ·) = u2 ∈ L (R) for a wave equation with variable...

The UNIQUAC activity coefficient model is extended to predict solid-liquid equilibrium of isotactic crystalline poly (1-butene), iPBu-1, in different organic solvents. The UNIQUAC activity coefficient model used in this work is based on the concept of group contribution and consists of combinatorial, residual and free volume terms. To account for branching of atom groups in the monomer structur...

The previously developed dispersion activity coefficient model (ACM) is extended from a molecular to group contribution (GC) providing results of equal accuracy as the model. Contrary other GC-ACMs presented GC-ACM preserves topology information each molecule in mixture. Therefore, contrast DISQUAC, UNIFAC or COSMOSAC, where eliminated by assignment groups construction sigma-profiles, this new ...

A procedure is described for the calculation of activity and osmotic coefficients which is based upon a knowledge of the equilibria in solutl.on and assumed si.ngle-ion activity coefficients. The procedure permits one to introduce chemical equilibria of various types (ion-pairing, complexation, hydration, and hydrolysis) into a model which can be used to calculate values of the excess Gibbs ene...

Random coe cient regression models have been applied in di erent elds and they constitute a unifying setup for many statistical problems. The nonparametric study of this model started with Beran and Hall (1992) and it has become a fruitful framework. In this paper we propose and study statistics for testing a basic hypothesis concerning this model: the constancy of coe cients. The asymptotic be...