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Central Leather Research Institute, Adyar, Madras-600 020 Reliable stability constants for the CrAH, CrA, CrA2, CrA3, Cr(OH) and Cr2,A4- (OH)2 have been obtained at 50 ± 0.1º and I- 0.1 mol dm-3in the Cr(III)-glycine system by the computer based analysis of the potentiometric data. Ternary complexation of Cr(III) with glycine as the primary ligand (A) and malefic, maleic, or succinic acids as the secondary ligand (B) gives rise to CrAB, CrAB, and CrA2B (only in the systems with B -malonic or maleic acid) types of ternary complexes. The results suggest the marked stabilities of these ternary complexes over the corresponding binary analogues which may probably be accounted for by considering the charge neutralization and interligand inter­actions in the ternary systems. The results indicate the preferred formation of Cr(III) ternary chelates containing five and six membered rings rather than those with five and seven membered rings. The enhanced stability of the unsaturated mixed complexes, CrAB, over the saturated complexes of the type CrA2B or CrAB2 is evident from the results. Ion exchange and spectroscopic evidence have been obtained to support the existence of CrAB, CrA2B and CrAB2 ternary species in the Cr(III)-glycine(A)-malonic acid(B) system.

Department of Chemistry, Agra University, Agra-282 004 Manuscript received 26 November 1984, accepted 11 September 1986 The results of pH-metric studies on the formation of 1 : 1 : 1 : 1 MLL'L" quater­nary complexes, where M-LaIII, PrIII, NdIII ; L =1,2-diatninocyclohexane-N,N,N',N'- tetraacetic acid (CDTA) ; L'=1,2-dihydroxysuccinic acid (tartaric acid) ; and L" = 2- butenedioic acid (maleic acid), have been discussed in the present paper. The calcu­lated values of formation constants and free energy of formation of the resulting quaternary species, formed by the simultaneous chelation of all the three ligands to the metal ion, have been compared with those of the 1 : 1 : 1 M-CDTA-TAR/MIA ternary complex at constant temperature (15°) and ionic strength (0.1 M KNO3) of the medium. A comparison of the values of stability constants both in ternary as well as in quater­nary complexes reveal the order, LaIII < PrIII < NdIII in terms of metal ions, ternary < quaternary in terms of complex species, and tartaric acid > maleic acid in the case of dicarboxylic acids. The calculated values of the percentage dissociation (0.2746) of the ligand, in the case of quaternary complex formation indicate that maleic acid behaves as monodentate ligand in the lower pH range.

Department of Chemistry, V. S. S..D. College, Kanpur University, Kanpur-208 002 Manuscript received 27 July 1981, revised 26 April 1982, accepted 21 July 1982 Formation constants of ternary complexes of the types MAL+ and MAL [where M=Co(II), Ni(II) or Cu(II), A=dth(MAL+) or trp(MAL) and L= trp(MAL+ or sal(MAL)] have been determined in solution potentiometrically, to provide further evidence on complexation as a possible mode of action of fungicides. The formation tendency (Δ log KM) of these complexes has been found to be positive for MAL+ type of complexes which has been explained as being due to M→dth \(π\) - interaction and has also indicated Intramolecular aromatic ring stacking between the ring systems of the two Uganda. The negative valuesΔ log KM have been found to be due to weak M→trp π-interaction and absence of intramolecular aromatic ring stacking.

Thèse de 3ème cycle soutenue à la Faculté des Sciences de l'Université de Bordeaux; Jusqu'à ces dernières années, la chimie des composés fluorés des éléments de transition n'avait pas connu un grand développement. Les rares travaux effectués avaient été entrepis par voie aqueuse. Les études en phase solide étaient pratiquement inexistantes en raison sans doute des difficultés techniques auxquelles se heurtaient les expérimentateurs.Depuis 1958, les composés fluorés ou oxyfluorés ont connu un regain d'intérêt. La substitution partielle ou totale de l'oxygène par le fluor, en raison de la proximité de leurs rayons ioniques, permettait d'obtenir de nouvelles séries isomorphes des oxydes...; non disponible

Thèse d'Etat soutenue à la Faculté des Sciences de l'Université de Bordeaux; La variété monoclinique de la zircone se transforme en variété quadratique à une température qui, selon le mode de préparation et le degré de pureté de l'échantillon, varie entre 1000° et 1100°C. Cette transformation est réversible bien qu'elle s'effectue avec retard au refroidissement. Elle s'accompagne d'une importante anomalie dilatométrie : au chauffage la contraction en volume est de l'ordre de 5%, elle interdit l'emploi de la zircone pure comme réfréctaire...; non disponible

The thermodynamic properties and the T-x phase diagrams for liquid-solid equilibrium in II-VI and IV-VI ternary systems are described by a regular associated liquid solution model derived from that used by Jordan for ZnTe and CdTe and by the regular approximation for the solid solution. For the pseudo-binary systems exhibiting miscibility in both phases and monotonic variation of the liquidus and solidus curves, a general expression is obtained. It is independent of the interactions in the liquid, and is the same as for ideal non associated liquids. In the calculation of the ternary T-x phase diagrams five parameters are needed : the two interaction parameters α 1, α2, the two coefficients of dissociation, β 1, β2, obtained from the respective binary liquidus, and the interaction parameter W in the solid, derived from the pseudo-binary phase diagrams. Good agreement with experimental data is obtained for the pseudo-binary systems : ZnTe-CdTe, ZnTe-HgTe, ZnSe-ZnTe, CdTe-HgTe, CdTe-CdSe, HgTe-HgSe, PbSe-PbTe, PbTe-SnTe, and for the ternary systems : Zn-Cd-Te and Pb-Sn-Te. The theory is especially suited for the case β ≃ 0 and α is small. It is applied to the calculation of the chalcogen-rich part of the ternary systems : Cd-Hg-Te and Cd-Se-Te.

Specific interaction of m-dinitrobenzene with naphthalene, phenanthrone and anthracene melanin has been studied in carbon tetrachloride. Solubility measurements of m-dinitrobenzene in carbon tetrichlorids indicate that the magnitude of the parameter A13decreases when small amounts of hydrocarbon mamba are added in the solvent. The addition of hydrocarbon molecules in the solvent, obviously creates some it which ere capable of specific interaction and, therefore, the value of the interaction parameter comes oak to be very much lower.

CD-Rom ISBN: 978-081691065-6; International audience; A detailed description of an experimental "in-house" set-up based on the "static-analytic" technique with gas phase capillary sampling designed, built, and improved to measure phase equilibria (pressure, temperature, and compositions) under gas hydrate formation conditions is presented in this work. The apparatus is suitable for measurements at temperatures ranging from (233 to 373) K and pressures up to 60 MPa. It was used to study phase equilibria in the carbon dioxide + methane + water system under hydrate formation conditions. An isochoric pressure-search method was used to measure hydrate dissociation conditions. The experimental data have been compared successfully with the literature data. The compositions of the gas phase in equilibrium with the hydrate and aqueous phases were measured using gas chromatography technique and compared successfully with the literature data. The compositions of the hydrate and aqueous phases were determined by applying material balance equations. The experimental data on the compositions of the hydrate have been compared successfully with the literature data. To solve the latter equations, the Newton's numerical method coupled with the Differential Evolution optimization strategy was employed. All the aforementioned experimental data (hydrate dissociation conditions + compositions analysis) have been compared with the predictions of two thermodynamic models, namely CSMGem and HWHYD. A discussion is made on the reliabilities of the predictions of the latter models.

Portland cement, calcium aluminate cement and calcium sulfate mixtures were investigated to determine the influence of sulfates and the effect of curing conditions on durability. This study focused on the richest mix of Portland cement. The PC/CAC ratio was kept constant at 5.67, and different proportions of calcium sulfate were added (0%, 1%, 3%, 5% and 10%). Samples were kept at 20 °C and 97% relative humidity or immersed in water. The dimensional change and mineralogical composition of samples were evaluated. The results showed that the dimensional change of samples in the PC/CAC and PC / CAC / C S ¯ systems depended on the amount of sulfate added and on the curing conditions. The dimensional change was associated not only with amorphous ettringite formation, but also with the subsequent formation of a C-S-H gel.

Different binders of Portland cement, calcium aluminate cement and calcium sulphate (PC/CAC/C $$ {\bar{\text{S}}} $$ ) have been investigated to determinate the influence the CAC and C $$ {\bar{\text{S}}} $$ amount in the reactions mechanism. Several mixtures were studied, ratios of 100, 85/15 and 75/25 of PC/CAC with 0, 3 and 5 % of C $$ {\bar{\text{S}}} $$ . Conduction calorimetric technique was used to follow the hydration during 100 h. The XRD and FTIR techniques were used as support in the analysis of the hydration products. The results have shown that the studied ternary systems form an extra amount of ettringite, and changes in the reactions mechanism with respect to a PC. The reactions mechanism depends on the CAC and C $$ {\bar{\text{S}}} $$ amount present in the different binders.

This work describes the energy and exergy analysis of a diesel engine integrated with a PCM based energy storage system, and provides more realistic and meaningful assessment than the conventional energy analysis. Using actual system data, the assessments of energy and exergy saved, and energy and exergy efficiencies are done. The exergy saved in the overall system is quantified and illustrated using an exergy flow diagram. Also, energy and exergy flow diagrams are compared. It is observed through the analysis that 6.13% of the total energy of the fuel is saved using the TES system. From the exergy analysis, it is identified that only 0.47% of the chemical availability of the fuel is saved. The energy efficiency of the integrated system is found to be varying between 3.19% and 34.15%. In contrast, the exergy efficiency, which incorporates the second law of thermodynamics for the integrated system, ranges from 0.25% to 27.41%.