Showing papers on "Ternary operation published in 1982"

Hydrides formed from intermetallic compounds of two transition metals: a special class of ternary alloys

Abstract: The authors review available experimental information on the existence, thermodynamic stability and physical properties of hydrides formed by the absorption of hydrogen gas in intermetallic compounds of two transition metals. The emphasis is on stability. It is shown that empirical models for the stability of ternary hydrides can be reconciled with ideas based on the results of band structure calculations of (binary) metallic hydrides. It is concluded that metallic hydrides can be looked upon as alloys of metallic hydrogen. In addition to the thermodynamic properties of ternary metallic hydrides the authors discuss experimental information on electronic properties (magnetic, super-conductivity, band structure features) and on crystallographic and metallurgical properties (neutron scattering, nuclear and electron spin resonance, Mossbauer spectroscopy, diffusion). Applications are briefly reviewed.

Polymer compatibility with and without a solvent

Abstract: A qualitative review of the thermodynamics of polymer systems will be given in terms of three contributions: positional (or combinatorial) entropy, an “international” term and a free volume term. From this one finds that a simple polymer-solvent system phase separates on lowering T to an Upper Critical Solution Temperature (UCST) or raising it to Lower Critical Solution Temperature (LCST), To achieve miscibility of two polymers of high molecular weight, one requires a “specific” interaction, usually a weak charge-transfer complex or a hydrogen bond. Phase separation takes place on raising the temperature to an LCST. These various UCST and LCST are predicted semi-quantitative by the Prigogine-Flory theory. When a solvent is added to two miscible polymers, a new type of phase separation appears since there is an effect of any difference in the strengths of the two polymer-solvent interactions. Phase separation may easily occur in the ternary system where there is none in the three binary systems, and examples will be given. In the case of two highly-attractive polymers in a solvent, a quite different phase separation occurs, sometimes called complex coacervation. A simple Flory-Huggins type theory predicts these phenomena in ternary systems.

Viscosity of some binary and ternary liquid mixtures

Abstract: Kinematic viscosities and densities of eight binary and four ternary liquid mixtures of polar components are reported for various temperatures. Experimental viscosities were correlated with McAllister's equation of viscosity and with a modified form of the McAllister equation.

Insights into the structure of alkali borate glasses

Abstract: In the light of extensive new glass transition temperature (Tg) and density (ϱ) data obtained for the ternary glass system Li2O(LiCl)2B2O3 we have re-examined the well accepted structural models developed for borate glasses by Krogh-Moe and co-workers. We find that, in contrast to the conclusions of NMR, Raman and IR spectroscopy, glasses in the binary and in the ternary systems with common O/B ratios do not exhibit identical boron-oxygen networks. Rather, we find that as LiCl in the ternary is increased the network is systematically weakened and expanded to accommodate the large Cl− anion. On the basis of these observations we question the ability of spectroscopic techniques such as Raman and NMR to confirm the uniqueness of structural models based on combinations of intermediate-range units. We propose a tentative model which is qualitatively in agreement with the observed changes in Tg and ϱ upon addition of LiCl, and explains how the large Cl− ions can be accommodated without large increases in energy due to strain and electrostatic effects while maintaining BO4/BO3 constant. Recent transport results on some fast ion conducting glasses in this system are also discussed in terms of the proposed model.

Flux-sintered BaTiO3 dielectrics

Abstract: BaTiO3 modified with BaZrO3 or SrZrO3 was sintered at 1100° C with the aid of various fluxes. The objective was to identify compositions in the system CdO-Bi2O3-PbO-B2O3 that would permit growth of the ceramic grains during sintering to produce dielectric constants greater than 5000 at room temperature. By studying binary, and then ternary flux systems initially, the roles of the flux components were identified and classified according to their solubility and mode of substitution in the titanate crystal lattice. This, together with close control of cation stoichiometry, resulted in the discovery of flux systems with other oxides substituting for CdO, Bi2O3 or B2O3 that produced similar results.

Structural effects in aqueous solutions: a thermodynamic approach

Abstract: The thermodynamic properties of aqueous solutions have been studied systematically over the years in our laboratory to gain insight on solute—solvent and solute—solute interactions, in particular those related to structural effects. Recently, our efforts have been largely concentrated on complex systems which show microheterogeneity beyond a certain concentration, e.g. micellar systems, some organic—water mixtures, mixed micelles and microemulsions. The concentration dependence of the thermodynamic properties of surfactants can be accounted for quantitatively with a mass—action model. The approach is similar to that of the two—state water model often used to understand the thermodynamic properties of liquid water. From the analysis of the data, it is possible to extract quantitatively the thermodynamic functions of micellization and the aggregation number. Properties of alcohol—water and amine—water mixtures, which also exist as microphases at high concentration, can be interpreted in a similar way. The same model can be extended to ternary systems such as electrolyte—surfactant—water in a way similar to the effect of a solute on the two—state equilibrium of water. It is also possible to consider cases where the solute not only shifts the equilibrium between monomers and micelles but also forms mixed micelles, e.g. mixtures of surfactants and alcohols. Finally, it is possible to account, at least qualitatively, for the thermodynamic properties of microemul— sions which are mixtures of water, hydrocarbon, surfactant and alcohol. INTRODUCTION Aqueous solutions have been systematically studied over the years in our laboratory primarily with the aim of obtaining information on solute—solvent and solute—solute interactions through thermodynamic properties (1). These interactions are particularly interesting in view of the high degree of structure in aqueous solutions, both in the solvent itself and in the aggregates that can exist as a result of the structure of water. Water is highly associated through hydrogen bonding and various solutes can increase or decrease the distribution of hydrogen bonds (see Fig. 1). Of particular importance are the hydrophobic solutes around which the water molecules tend to organize in a way similar to clathrate hydrates. These time—average complexes have a strong tendency to cluster leading to the

A simple procedure for the rapid optimization of reversed-phase separations with ternary mobile phase mixtures

Abstract: A simple rapid procedure is described for estimating optimum compositions of ternary mobile phase mixtures for the separation of samples by reversed-phase liquid chromatography (RPLC). Retention data in two iso-eluotropic binary mobile phase mixtures (mixtures with equal retention times) are required to initiate the procedure. The logarithm of the capacity factor is assumed to vary linearly with the composition of isoeluotropic ternary mixtures formed by mixing the two limiting binaries. Using the product of resolution factors of adjacent peaks as the criterion, an optimum ternary composition is then calculated. After a chromatogram has been obtained with the predicted optimum ternary mobile phase, the procedure is repeated until no further improvement can be achieved. Examples of the application of the present procedure are described to illustrate its effectiveness.

Pyrazole binding in crystalline binary and ternary complexes with liver alcohol dehydrogenase

Abstract: Pyrazole is a strong inhibitor of liver alcohol dehydrogenase in combination with oxidized coenzyme NAD+. We have studied three different complexes of the inhibitor with the enzyme by using crystallographic methods: (1) the binary complex with pyrazole to 3.2-A resolution, (2) the ternary ternary complex with NAD+-4-iodopyrazole to 2.9-A resolution. Crystals of the binary complex are isomorphous to the apoenzyme, and pyrazole binds to the active-site zinc atom in a way analogous to imidazole. Crystals of the two ternary complexes are isomorphous with the ternary alcohol dehydrogenase-NADH-dimethyl sulfoxide complex. One of the nitrogen atoms of the pyrazole ring is directly bound to the active-site zinc atom with a Zn-N bond distance of 2.1A. The other nitrogen atom is 2 A from the C4 atom of the nicotinamide ring of the coenzyme. The iodine atom in 4-iodopyrazole is located in the hydrophobic substrate cleft. The effect of substitutions on the pyrazole ring are discussed in relation to the structure of the active site and substrate pocket. Pyrazole derivatives with long alkyl chains bound in the 4 position are outstanding inhibitors, and this property is related to the topography of the hydrophobic substrate cleft. The conformation of the oxidized coenzyme in the ternary complexes is essentially the same as that of the reduced coenzyme NADH in the NADH-dimethyl sulfoxide complex.

A theoretical model of the linear electro-optic effect

Abstract: A simple theoretical study of the linear electro-optic effect is presented. This semiclassical approach is based on the single-energy-gap model, the dielectric theory and the concepts of bond charge and effective ionic charge. A general expression is obtained for the electro-optic coefficient of a crystal and is applied to a wide variety of diatomic and ternary compounds including zincblende (GaAs, GaP, ZnSe, ZnS, ZnTe, CuCl), wurtzite (ZnS, CdS, CdSe), quartz (SiO2), lithium niobate (LiNbO3, LiTaO3), KDP (KH2PO4, KD2PO4, NH4H2PO4), chalcopyrite (AgGaS2, CuGaS2) and proustite (Ag3AsS3). The calculated results are generally in good agreement with experiment.

Surface segregation in austenitic stainless steel

Abstract: We report in this paper a study of surface segregation in austenitic stainless steel. Auger electron spectroscopy was used to measure segregation as a function of time and temperature. We have found that P, N, S, Cr, and Ni will all segregate to the surface. However, their presence on the surface often depends on the competitive and attractive interactions between the various elements. We show that thermodynamic data on ternary liquid iron alloys are quite valuable in predicting these interactions. We also discuss possible applications of these studies.

Ternary equilibrium diagrams

Abstract: General considerations. Systems containing two phases. Systems containing three phases. Systems containing four phases. Systems containing more than four phases. Principles of using liquid projections. Complex systems.

Chemistry and Structure of Ternary Molybdenum Chalcogenides

Abstract: The preparation and the structural properties of MxMo6X8 (X = chalcogen) compounds are reviewed. The very large facility of substitution of M, Mo, or X elements often involves a drastic change in the physical properties. The new clusters Mo9, Mo12, (Mo6/2) ∞ 1 resulting from a condensation of octahedral Mo6 clusters are exhibited.

Synthesis and crystal structures of Ba2Re6S11 and Sr2Re6S11, compounds containing [Re6S8] clusters

Abstract: The ternary sulphides Ba2Re6S11 and Sr2Re6S11 were synthesized by the reaction of the alkaline earth carbonates with rhenium at 1350 °C and 1450 °C respectively in a stream of H2S. X-ray investigations on single crystals gave the structure of Ba2Re6S11. The atomic arrangement consists of a framework in which [Re6S8] clusters are linked in three dimensions according to the formulation { Re 6 S 8 ]S 6 2 } 4− . The barium ions are inserted in holes of this framework. Powder diffraction investigations showed that Sr2Re6S11 has a structure analogous to that of Ba2Re6S11. Measurements of the magnetic susceptibilities between 3.7 and 295 K show that Ba2Re6S11 has a diamagnetic behaviour. The distortion of [M6X8] clusters is discussed with respect to electronic configuration.

Peculiar electric and photoelectric behavior of lead-containing perovskite-type oxides

Abstract: Electrophysical properties and photoconductivity of several binary (PbTiO3, PbZrO3, PbHfO3) and ternary (Pb2ScNbO6, Pb2InNbO6) lead-containing perovskite-type oxides were investigated. Band gap energies for all studied compounds were measured to be somewhat smaller than for its perovskite analogs not containing lead. This fact is ascribed to a specific configuration of the outer electronic shell of lead.Owing to high photosensitivity of the lead-containing perovskites, a considerable effect of electronic subsystem (in particular of the non-equilibrium carriers) on crystal properties both in ferroelectric and antiferroelectric crystal phases was observed.

Glass-Forming Systems Involving GeO2 with Bi2O3, Ti2O, and PbO

Abstract: The previously studied system GeO2-Bi2O3-TI2O was extended with the addition of PbO using air- and water-quenched melted samples. Large areas of glass formation were found in the systems GeO2–Bi2O3–PbO and GeO2–PbO–Tl2O at all but the lowest GeO2 contents. Glasses were examined by powder X-ray diffraction, differential thermal analysis, thermomechanical analysis, and Archimedes’technique to obtain glass transition and crystallization exotherm temperatures, thermal expansion coefficients, and densities, which are presented in diagrams for the GeO2-PbO binary and for the two ternary systems. Based on calculated values of λ0, the wavelength for zero material dispersion, compositions in this system may be useful for construction of ultralow-loss optical waveguides in the μm region.

Numerical solution of liquid-phase multicomponent adsorption in fixed beds

Abstract: A generalized mathematical model is developed to describe the process of multicomponent adsorption on activated carbon in fixed beds. Numerical, finite difference, solutions for the adsorption of binary, and ternary organic mixtures are shown to satisfactorily match previously published experimental data.