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Stefano Besseghini - One of the best experts on this subject based on the ideXlab platform.

  • A complete thermo-mechanical study of a NiTiCu shape memory alloy wire
    Journal of Thermal Analysis and Calorimetry, 2011
    Co-Authors: Adelaide Nespoli, Stefano Besseghini
    Abstract:

    Shape memory alloy mechanical performance and phase transformation temperatures depend on the composition of the alloy, on the thermo-mechanical history, and on the applied load. For this reason is important to execute a deep investigation of the SMA material before its final use. In this study we investigate the thermo-mechanical behavior of a NiTiCu wire under stress-free condition through the differential scanning calorimetry and the electrical resistance measurements and under load through tensile and hysteresis tests. The phase transformation temperature dependence on the applied load, by means of the Clausius-Clapeyron Equation, as well as on the thermal treatment temperature are also studied. © 2010 Akadémiai Kiadó, Budapest, Hungary.

  • Elastic and Superelastic Properties of NiFeCoGa Fibers Grown by Micro-Pulling-Down Method
    Materials Transactions, 2009
    Co-Authors: Katsunari Oikawa, Stefano Besseghini, Ryo Saito, Koichi Anzai, H. Ishikawa, Yuji Sutou, Toshihiro Omori, Akira Yoshikawa, V. A. Chernenko, A. Gambardella
    Abstract:

    Low-frequency elastic modulus, internal friction, tensile stress-strain loops, and thermally-induced strain recovery of single-crystal fibers obtained by pulling-down method from the melts of NiFeGaCo alloys were studied. A minimum of the elastic modulus and the maximum peak of the internal friction were obtained at the martensitic transition temperature. A large super-elastic strain of about 10% was obtained in the fiber of the Ni49Fe18Ga27Co6 alloy. Thermodynamic estimation by the Clausius-Clapeyron Equation was consistent with the experimental results.

T R A Magee - One of the best experts on this subject based on the ideXlab platform.

  • the determination of sorption isotherm and the isosteric heats of sorption for potatoes
    Journal of Food Engineering, 1998
    Co-Authors: C P Mclaughlin, T R A Magee
    Abstract:

    Abstract Sorption isotherms were determined for potatoes at three different temperatures, (30, 45 and 60 °C), using a standard gravimetric method. The goodness of fit of four sorption models to experimental results was determined. Of the models tested the GAB, Oswin and Hasley models gave good fits while the BET model gave a poor fit. Monolayer moisture contents determined from these models were found to decrease with increasing temperature. The net isosteric heat of sorption was determined for potatoes at 45 °C from sorption data using the Clausius-Clapeyron Equation. Isosteric heats of sorption were found to increase with increasing temperature and fitted well with empirical exponential relationship.

Demetris Koutsoyiannis - One of the best experts on this subject based on the ideXlab platform.

  • Corrigendum: Clausius–Clapeyron Equation and saturation vapour pressure: simple theory reconciled with practice
    European Journal of Physics, 2012
    Co-Authors: Demetris Koutsoyiannis
    Abstract:

    An error related to a partial derivative, which affected some statements in the original paper but not the final results or their derivation, is corrected. At the end of Section 4, entitled “Alternative derivation in a statistical mechanical framework”, of my paper [1], an analysis of chemical potentials of the liquid and gaseous phase has been included. This analysis starts with Equation (36) which provides the definition of chemical potential in terms of the partial derivative of entropy with respect to the number of particles. While the Equation is correct as shown, the partial derivative should be meant for constant internal energy U rather than constant thermal energy E as used in the paper. The two are identical for the gaseous phase but differ for the liquid phase as EL = UL + NLξ. Consequently, the partial derivatives, L L L L / ) , ( N N U S ∂ ∂ and L L L L / ) , ( N N E S ∂ ∂ , will differ too, as implied by the chain rule: L L L L ) , ( N N U S ∂ ∂ = L L L L ) , ( N N E S ∂ ∂ + L L L L ) , ( E N E S

  • Clausius-Clapeyron Equation and saturation vapour pressure: simple theory reconciled with practice
    European Journal of Physics, 2012
    Co-Authors: Demetris Koutsoyiannis
    Abstract:

    While the Clausius"Clapeyron Equation is very impo rtant as it determines the saturation vapour pressure, in practice it is replaced by empirical, typically Magnus type, Equations which are more accurate. It is shown that the reduced accuracy reflects an inconsistent assumption that the latent heat of vaporization is constant. Not only is this assumption unnecessary and excessive, but it is also contradictory to entropy maximization. Removing this assumption and using a pure entropy maximization framework we obtain a simple closed solution, which is both theoretically consistent and accurate. Our discussion and derivation are relevant to students and specialists in statistical thermophysics and in geophysical sciences, and our results are ready for practical application in physics as well as in such disciplines as hydrology, meteorology and climatology.

J. K. Chen - One of the best experts on this subject based on the ideXlab platform.

  • Melting, Vaporization, and Resolidification in a Thin Gold Film Irradiated by Multiple Femtosecond Laser Pulses
    Journal of Manufacturing Science and Engineering-transactions of The Asme, 2013
    Co-Authors: Yuwen Zhang, J. K. Chen
    Abstract:

    Melting, vaporization, and resolidification in a gold thin film subject to multiple femtosecond laser pulses are numerically studied in the framework of the two-temperature model. The solid-liquid phase change is modeled using a kinetics controlled model that allows the interfacial temperature to deviate from the melting point. The kinetics controlled model also allows superheating in the solid phase during melting and undercooling in the liquid phase during resolidification. Superheating of the liquid phase caused by nonequilibrium evaporation of the liquid phase is modeled by adopting the wave hypothesis, instead of the Clausius–Clapeyron Equation. The melting depth, ablation depth, and maximum temperature in both the liquid and solid are investigated and the result is compared with that from the Clausius–Clapeyron Equation based vaporization model. The vaporization wave model predicts a much higher vaporization speed, which leads to a deeper ablation depth. The relationship between laser processing parameters, including pulse separation time and pulse number, and the phase change effect are also studied. It is found that a longer separation time and larger pulse number will cause lower maximum temperature within the gold film and lower depths of melting and ablation.

  • Melting, Vaporization and Resolidification in a Thin Gold Film Irradiated by Multiple Femtosecond Laser Pulses
    Volume 1: Heat Transfer in Energy Systems; Theory and Fundamental Research; Aerospace Heat Transfer; Gas Turbine Heat Transfer; Transport Phenomena in, 2012
    Co-Authors: Yuwen Zhang, J. K. Chen
    Abstract:

    Melting, vaporization and resolidification in a gold thin film subject to multiple femtosecond laser pulses are numerically studied in the framework of the two-temperature model. The solid-liquid phase change is modeled using kinetics controlled model that allows the interfacial temperature deviates from the melting point. The kinetics controlled model also allows superheating in the solid phase during melting and undercooling in the liquid phase during resolidification. Superheating of the liquid phase caused by nonequilibrium evaporation of the liquid phase is modeled by adopting the wave hypothesis, instead of Clausius-Clapeyron Equation. Melting depth, ablation depth, and maximum temperature in both liquid and solid are investigated and the result is compared with that from Clausius-Clapeyron Equation based vaporization model. The vaporization wave model predicts a much higher vaporization speed which leads to a deeper ablation depth. The relationship between laser processing parameters, including pulse separation time and pulse number, and phase change effect are also studied. It is found that longer separation time and larger pulse number will cause lower maximum temperature within the gold film, as well as lower depths of melting and ablation.© 2012 ASME

Dorothea M Hillesheim - One of the best experts on this subject based on the ideXlab platform.

  • thermodynamic study on the sublimation of 1 2 diphenylethane and of 3 phenylpropiolic acid
    The Journal of Chemical Thermodynamics, 2001
    Co-Authors: Manuel J S Monte, Dorothea M Hillesheim
    Abstract:

    Abstract The Knudsen mass-loss effusion technique was used to measure the vapour pressures at different temperatures of the following crystalline compounds: 1,2-diphenylethane (bibenzyl), between T  =  289.16 K and T  =  303.20 K, and of 3-phenylpropiolic acid between T  =  329.15 K and T  =  343.15 K. From the temperature dependence of the vapour pressure, the standard molar enthalpies of sublimation at the mean temperature of the experimental range were derived by the Clausius–Clapeyron Equation. From these results the standard, p o  =  10 5 Pa, molar enthalpies, entropies, and Gibbs energies of sublimation at T  =  298.15 K, were calculated: