Molar isobaric heat capacities, C-pm, and molar excess isobaric heat capacities, C-pm(E), are reported for 1-butanol, 1-octanol or 1-decanol + benzylamine systems at (293.15, 308.15, 318.15, 333.15) K. C-pm(E) values were measured with a Setaram Micro DSC II microcalorimeter using a scanning method. The investigated mixtures are characterized by large and positive C-pm(E) (x(1) = 0.5) values at 298.15 K, which remarks that self-association and/or solvation effects are predominant in such solutions. The C-pm(E) curves are skewed towards higher mole fractions of the alcohol, which suggests that alcohol-amine interactions are more probable in that region. In addition, for a given 1-alkanol, C-pm(E) (x(1) = 0.5) decreases when temperature increases, due to alcohol dissociation is larger at elevated temperatures. The lower self-association of longer 1-alkanols and lower solvation effects may explain that the C-pm(E) (x(1) = 0.5) change with temperature is sharper for the solutions with the mentioned alcohols. The observed decrease of C-pm(E) (x(1) = 0.5) with the increasing of the chain length of the alcohol at enough high temperatures may be explained in similar terms. (C) 2014 Elsevier B.V. All rights reserved.

Molar excess heat capacities, C-pm(E). are reported for the benzylamine + heptane mixture at 293.15K and for methanol, 1-propanol or 1-pentanol + benzylamine systems at 293.15-308.15 K. These values were determined from isobaric molar heat capacities obtained with a Setaram Micro DSC II microcalorimeter using a scanning method. The heptane solution shows a W-shaped C-pm(E) concentration dependence, which reveals the existence of strong non-random effects. Systems including 1-alkanols are characterized by large and positive C-pm(E),, values. This remarks that self-association and/or solvation effects are predominant in such solutions. On the other hand, their C-pm(E) curves are skewed towards higher mole fractions of the alcohol, which might be ascribed to the existence of more interactions between unlike molecules in that region. (C) 2014 Elsevier B.V. All rights reserved.

A study of thermal properties of CuO dispersed in water and ethylene glycol as a function of the particle volume fraction and at temperatures between 298 and 338 K has been performed. Thermal conductivities have been studied by the steady-state coaxial cylinders method, using a C80D microcalorimeter (Setaram, France) equipped with special calorimetric vessels. Heat capacities have been measured with a Micro DSC II microcalorimeter (Setaram, France) with batch cells designed in our laboratory and the “scanning or continuous method.” Results for thermal conductivities can be well justified using a classical model (Hamilton–Crosser), and experimental measurements of heat capacities can be justified with a model of particles in thermal equilibrium with the base fluid.

A study of a steady-state method for thermal conductivity measurements of liquids has been carried out. It uses a C80D differential micro-calorimeter from Setaram (France), with special designed vessels containing a heating resistance. The thermal conductivity k of a liquid sample is determined as a function of the heat flow measured by the calorimeter, using an expression whose coefficients are found through the calibration with three reference liquids. These coefficients change with the calorimeter temperature, so the calibration has to be performed at each temperature. In this work, it has been verified that the coefficients' temperature variations can be justified by the thermal properties of the calorimeter components. A new model valid for all temperatures has been developed, taking into account those factors. This new model confirms the physical meaning of the procedure, brings down the number of measurements required for the calibration, and slightly reduces the uncertainty of the results.

A study has been carried out of calorimetric cells based on the coaxial cylinder method suitable for the thermal conductivity measurements in a C80D micro-calorimeter from Setaram (France). On the hypothesis of a pure conductive process, it has been possible to obtain the equation expressing the thermal conductivity k of a liquid sample in function of the heat flow measured by the calorimeter, and the relative thermal conductivity uncertainty has been analysed. To justify the hypothesis of practical absence of convection and negligible temperature differences during experimentation, a CFD (Computational Fluid Dynamics) study has been performed. With a view to testing our equipment and calibration method, the thermal conductivities of some pure liquids (toluene, n-decane) and systems (water + ethanol and nanofluid water/Al2O3), which cover a wide range, have been measured.

The dispersion and stability of nanofluids obtained by dispersing Al2O3 nanoparticles (obtained from different sources) in water have been analyzed. The differences arising from different dispersion techniques, the resulting particle size distribution, and time stability among the different samples are evaluated. Then the volumetric behavior up to high pressures (25 MPa) and atmospheric pressure viscosity were experimentally determined. It has been found that the influence of particle size in density is subtle but not negligible, but the differences in viscosity are very large and must be taken into account for any practical application. These viscosity differences can be rationalized by considering a theory describing the aggregation state of the nanofluid.

The saturated heat capacities of some linear alkylbenzenes (ethylbenzene, propylbenzene, butylbenzene, hexylbenzene, 1-phenylheptane, and 1-phenylhexadecane) and branched alkylbenzenes (in-xylene, cumene, (1-methylpropyl)benzene, (1,1-dimethylethyl)benzene, and (2-methylpropyl)benzene) in the temperature range from (332.15 to 401.15) K have been measured. A Calvet calorimeter C80D from Setaram (France) with batch cells modified from the standard vessels of Setaram, along with the "step by step method", has been used to perform the measurements. The estimated uncertainty of the saturated heat capacities was better than 0.5 % for the substances with higher purity and of the order of 1 % for the others. In the literature there exists C-sat(T) data for some of the liquids studied. Agreement with our measurements is within the range of the experimental uncertainties.

The saturated heat capacities of oxygenated gasoline additives methyl tert-butyl ether (MTBE), ethyl tert-butyl ether (ETBE), diisopropyl ether (DIPE), and tert-amyl methyl ether (TAME) in the temperature range of 277.15 K to some degrees below their normal boiling temperatures have been measured. A Micro DSC II from Setaram (France) with batch cells designed in our laboratory and the "scanning method" were used to perform the measurements. The estimated uncertainty of the saturated heat capacities was better than 0.3%. In the literature, there exist C-sat(T) data for some of the liquids studied. Agreement with our measurements is within the range of the experimental uncertainties. At each temperature, the saturated heat capacity of liquid MTBE is smaller than those of ETBE, DIPE, and TAME, and the corresponding C,at values of these three liquids are similar. This behavior can be related with the surface fraction of the ether group in each molecule.

The saturated heat capacities of benzene and of some linear (toluene, ethylbenzene, propylbenzene, butylbenzene, hexylbenzene, 1-phenylheptane, and 1-phenylhexadecane) and branched ( m -xylene, cumene, sec-butylbenzene, tert-butylbenzene, and isobutylbenzene) alkyl-benzenes have been measured. A Micro DSC II from Setaram (France) with batch cells designed in our laboratory, and the “scanning or continuous method,” have been used to perform the measurements. The estimated uncertainty of the saturated heat capacities was better than 0.3%. In the literature there exists c sat ( T ) data for some of the liquids studied. Agreement with our measurements is better than 0.5%. For linear alkyl-benzenes and for each temperature, the variation in the saturated heat capacity with the alkyl length is nearly linear. The selected branched alkyl-benzenes are isomers of the linear alkyl-benzenes studied; accordingly, the influence of molecular structure on the saturated heat capacities has been analyzed.

New "batch" cells adapted to measure saturated heat capacities with a Micro DSC II (Setaram) microcalorimeter designed to avoid any leakage during measurement are described. Using the "scanning" and "step-by-step" methods, the heat capacities of pure organic liquids-hexane, heptane, decane, dodecane, cyclohexane, toluene, methanol, and 1-butanol-in the temperature range (5 to 75) degreesC were determined. In addition, the excess heat capacities of several binary liquid mixtures-(benzene + cyclohexane) and (2,5,8,11-tetraoxadodecane + dodecane)-with the step-by-step procedure were measured. A very close agreement with literature values better than 1% indicates that the apparatus and technique are suitable for heat capacity measurements on volatile liquids.