Sorensen value

Sorensen value — Obsolete term for the numerical value of -> pH. Sorensen used the term -> hydrogen ion exponent for pH. 

Although the SOrensen value is erroneous, it appears preferable, at least for the time being, to retain it because the pH of most buffer solutions described in the literature is calculated by Sorensen s equations. All Sorensen values will be readily convertible into poH, once the constant difference between pH (Sorensen) and paH has been established. At present, such a recalculation would merely add to the confusion already encountered, for various authors do not agree upon the value of this difference between pH (Sorensen) and paH. 

The following table has been constructed after a critical study of all pKi values of indicators published in the literature. The reader must realize that these values are based upon the Sorensen value of pH 1.04 in 0.1 N hydrochloric acid or 2.04 in a mixture of 0.01 N HCl and 0.09 N KCl. 

The vertebrates produce, send and detect information which is conveyed by one or more molecular types. Chemical information of biological value (semiochemicals) which partly or wholly activates the accessory olfactory system (AOS) is transferred during intra- and inter-species communication. The compounds involved convey messages of social importance originating from the need to co-ordinate gamete release. It seems quite likely that gradual improvements by selection of semiochemical molecules and their receptors eventually enhanced the reproductive benefits both for the sender and for the receiver (Sorensen, 1996). The dual olfactory systems interpret chemical input to allow the discrimination of odour... 

By plotting the left-hand side of eqn. 2.65 against to and extrapolating back to to = 0 the intercept at to = 0 gave the value of J lgci/Ag = 0.2225 V at 25° C20 (cf., 0.2223 V21). Once E° is known, the measurement of E as a function of to provides an important method for determining molal ionic activity coefficients and a paH scale with the above type of cell, which permits a comparison with the Sorensen psH scale (cf., p. 33). 

The optimum UNIQUAC interaction parameters u, between methylcyclohexane, methanol, and ethylbenzene were determined using the observed liquid-liquid data, where the interaction parameters describe the interaction energy between molecules i and j or between each pair of compounds. Table 4 show the calculated value of the UNIQUAC binary interaction parameters for the mixture methanol + ethylbenzene using universal values for the UNIQUAC structural parameters. The equilibrium model was optimized using an objective function, which was developed by Sorensen [15],... 

Romo, T.D., Clarage, J.B., Sorensen, D.C., Phillips, G.N. Automatic identification of discrete substates in proteins-singular-value decomposition analysis of time-averaged crystallographic refinements. Proteins 1995, 22, 311-21. 

The polysaccharide compositions of potato cell walls have been genetically manipulated for two main reasons first to attempt to understand the functions of the different cell-wall polysaccharides, and second to improve the value of potato pulp waste. The yield of pectin extracted from the pulp would be improved by decreasing the proportion of cellulose in the walls. The gelling quality of this pectin would also probably be improved by reducing the proportion of RG-1 side chains (Sorensen et al., 2000). 

Most solutions we meet have a pH in the range 0 to 14, but values outside this range are possible. The pH scale was introduced by the Danish chemist Soren Sorensen in 1909 in the course of his work on quality control in the brewing of beer and is now used throughout science, medicine, and engineering. 

Based on the principle that the first non-toxic dilution level is used for numerical classification of liquid samples, toxicity can be expressed in the form of the negative binary logarithm of the dilution factor. In similar fashion to the pH value introduced by S.P.L. Sorensen in 1909 as a measure in chemistry, this measure of toxicity is called the pT-value (Krebs, 1987). 

Kosower, E.M., Wu, G.-S., and Sorensen, T.S. (1961) Effect of solvent on spectra. VI. Detection of the solvent effed on molecular conformation or shape through Z-values. Journal of the American Chemical Society, 83, 3147-3154. 

LLE data cannot be checked for thermodynamic consistency as can be done for vapor-liquid equilibria data (Sorensen and Arlt, 1979). In VLE systems, one of the set of equilibrium values (T, P, Xj, yj) is calculated from the other and checked against experimental data. For LLE systems, pressure has a small influence on the other quantities. Therefore, pressure cannot be included in such a consistency test. 

Some kinetic data found in literature are referred to the conventional (Sorensen) pH scale [7] or, in a few cases, to the paH scale [7] (paH = —log aH). Application of the conventional pH scale is certainly useful in kinetic experiments which are done for practical purposes (such as stability studies of drugs in solution). Matters are different, however, if it is intended to determine well defined values of the catalytic coefficients fcH or ft oh As mentioned above, the pcH scale is most recommendable for an evaluation of the rate equation from experimental data — particularly if the dependence of the rate on [H+] is complicated. Only if the pcH scale is used, ftH and fcoH values (referred to concentrations) determined with dilute solutions of strong acids or strong bases will be identical with those measured in buffer solutions at the same ionic strength. ... 

Sorensen, J. P., and W. E. Stewart, Structural analysis of multicomponent reactor models I. Systematic editing of kinetic and thermodynamic values, AIChE J., 26, 98-104 (1980). 

Figure 2.64. Isodensity surfaces (at the value of 0.05) for the Mg (darkest) and H (lighter shaded) atoms of a unit cell in the equilibrium structure of the metal hydride MgHj (Sorensen, 2004f).

Figure 3.10. Potential energy surface of two water molecules over an Ni surface, as a function of height over the surface (z measured from the second layer of Ni atoms) and 2e, the distance between the oxygen atoms. The quantum chemical calculation of the potential energies employs Hartree-Fock for the two layers of 24 Ni atoms and density functional theory (B3LYP) for the rest, the set of basis function called SV (cf. section 3.2). Ihe position of the water molecules for one set of parameter values is shown in the insert. The zero of the energy scale is chosen arbitrarily (Sorensen, 2004b).

Figure 3.12. Potential energy for the Ni plus two water molecule system as in Fig. 3.10, with the distance of the H atoms from the relevant O atom varied from the value g = 0.096 nm valid for an isolated water molecule. The O atoms are 2e = 0.24 nm apart, and the distance over the Ni surface is kept at the value z = 0.4 nm, leading to the minimum potential energy for all values of g (Sorensen, 2004b).

The total externality costs (i.e., those not reflected in direct consumer costs) are summarised in Table 6.10. This involves translating the impacts from physical units to common monetary units, with the problems inherent in such an approach, notably valuing the loss of a human life to society. The caveats are associated with the fact that impacts such as accidental deaths are not always occurring in the same society that harvests the benefits of car driving. These issues have been discussed, e.g., in Sorensen (2004a). 

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