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Abstract  

The molality dependence of specific conductivity of pentadecyl bromide, cetylpyridinium bromide and cetylpiridinium chloride in aqueous solutions has been studied in the temperature range of 30–45 °C. The critical micelle concentration (cmc) and ionization degree of the micelles, β, were determined directly from the experimental data. Thermal parameters, such as standard Gibbs free energy
\documentclass{aastex} \usepackage{amsbsy} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{bm} \usepackage{mathrsfs} \usepackage{pifont} \usepackage{stmaryrd} \usepackage{textcomp} \usepackage{upgreek} \usepackage{portland,xspace} \usepackage{amsmath,amsxtra} \pagestyle{empty} \DeclareMathSizes{10}{9}{7}{6} \begin{document} $$\Updelta G_{m}^{0} ,$$ \end{document}
enthalpy
\documentclass{aastex} \usepackage{amsbsy} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{bm} \usepackage{mathrsfs} \usepackage{pifont} \usepackage{stmaryrd} \usepackage{textcomp} \usepackage{upgreek} \usepackage{portland,xspace} \usepackage{amsmath,amsxtra} \pagestyle{empty} \DeclareMathSizes{10}{9}{7}{6} \begin{document} $$\Updelta H_{m}^{0}$$ \end{document}
and entropy
\documentclass{aastex} \usepackage{amsbsy} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{bm} \usepackage{mathrsfs} \usepackage{pifont} \usepackage{stmaryrd} \usepackage{textcomp} \usepackage{upgreek} \usepackage{portland,xspace} \usepackage{amsmath,amsxtra} \pagestyle{empty} \DeclareMathSizes{10}{9}{7}{6} \begin{document} $$\Updelta S_{m}^{0} ,$$ \end{document}
of micellization were estimated by assuming that the system conforms to the pseudo-phase separation model. The change in heat capacity on micellization
\documentclass{aastex} \usepackage{amsbsy} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{bm} \usepackage{mathrsfs} \usepackage{pifont} \usepackage{stmaryrd} \usepackage{textcomp} \usepackage{upgreek} \usepackage{portland,xspace} \usepackage{amsmath,amsxtra} \pagestyle{empty} \DeclareMathSizes{10}{9}{7}{6} \begin{document} $$\Updelta C_{p} ,$$ \end{document}
was estimated from the temperature dependence of
\documentclass{aastex} \usepackage{amsbsy} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{bm} \usepackage{mathrsfs} \usepackage{pifont} \usepackage{stmaryrd} \usepackage{textcomp} \usepackage{upgreek} \usepackage{portland,xspace} \usepackage{amsmath,amsxtra} \pagestyle{empty} \DeclareMathSizes{10}{9}{7}{6} \begin{document} $$\Updelta H_{m}^{0} .$$ \end{document}
An enthalpy–entropy compensation phenomenon for the studied system has been found.
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Abstract  

The aim of this work was to demonstrate, by means of thermoanalytical methods (DTA, TG and DTG), that sepiolite from Vallecas (Spain) is mixed with another mineral which is difficult to determine by X-ray diffraction and chemical analysis in routine mineralogical studies. The low temperature endothermic effect and weight loss shown by this material can be separated into two effects: one from sepiolite and the other from an accompanying mineral-identified as a magnesium smectile. The concentration of this latter mineral in the mixture attained up to 15%.

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Abstract  

Electrical conductivity of aqueous solutions of dodecylpyridinium chloride and bromide have been determined. From these data the critical micelle concentration (cmc) was determined. The thermal properties as standard Gibbs free energy, enthalpy and entropy of micellization was estimated from a uncharged-phase separation model and enables to obtain another properties like heat capacity of micellization and the relevant parameters in the minimum of temperature dependence of cmc. The enthalpy-entropy compensation was shown for the studied compounds.

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Journal of Thermal Analysis and Calorimetry
Authors: J. Galán, J. Del Castillo, A. González-Pérez, V. Fuentes-Vázquez, and J. Rodríguez

Abstract  

The specific conductivities of dodecylpyridinium chloride have been determinated in water-butanol/pentanol/hexanol solutions in the temperature range of 10 to 35C, and butanol, pentanol and hexanol concentrations up to 0.05 mol kg–1. From these data the temperature dependence of the critical micelle concentration, (cmc), was determined. The molar fraction of alcohol in the micelle was estimated using the theory suggested by Motomura et al. for surfactant binary mixtures. The standard Gibbs free energy of solubilization of alcohols in the micelles was worked out using the phase separation model.

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The thermal behaviour of some 2-benzylamino-2-deoxyheptonic acids obtained from 2-benzylamino-2-deoxy-D-glycero-L-gluco, 2-benzylamino-2-deoxy-D-glycero-D-ido and 2-benzylamino-2-deoxy-D-glycero-D-taloheptononitriles (reported) previously has been studied in air (static atmosphere) and N2 (dynamic atmosphere, flow rate 200 ml/min).

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Cereal Research Communications
Authors: E. Martínez-Cruz, E. Espitia-Rangel, H. Villaseñor-Mir, J. Molina-Galán, I. Benítez-Riquelme, A. Santacruz-Varela, and R. Peña-Bautista

The influence of allelic variants of HMW Gand LMWG on viscoelastic properties of dough was evaluated in parents and 98 recombinant lines derived from the crosses Rebeca F2000 × Verano S91 and Galvez M87 × Bacanora T88. Genotypes were grown at Roque, Guanajuato during the Spring-Summer of 2008. Studied traits were mixing time, mixing stability and over-mixing tolerance, general strength of the dough and tenacity/extensibility ratio. HMWG alleles 1, 2*, 17 + 18 and 5 + 10 favored the quality of the dough and variants 2 + 12 and 7 + 9 were associated with low levels of gluten strength. A 7 + 9 allele was associated with genotypes prone to form tenacious dough. Alleles Glu-A3c, Glu-A3e, Glu-B3g and Glu-B3h from the cross Rebeca F2000 × Verano S91 affected positively the quality of gluten, while allelic variants Glu-A3b, Glu-B3h and Glu-D3c in the cross Galvez M87 × Bacanora T88 were associated with higher quality standards and its counterparts Glu-A3c, Glu-B3j and Glu-D3b were associated to lower quality parameters. Results also shown interaction among loci, hence breeders need to be aware not only of the effect of individual alleles but also its interaction.

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