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Abstract
Zeolite-water heat-pump system is suitable for effective use of low temperature heat sources such as solar energy and waste heats from factories, that is,for energy saving. The heat exchange function of zeolite owes obviously to the nature of the zeolitic water, the state of which can be described in terms of the entropy value as an independent component of H2O. Most entropy values of zeolitic water have been given so far to be intermediate between those of liquid water (69.9 J mol-1 K-1 at 298 K) and ice (41.5 J mol-1 K-1 at 273 K).The present calorimetric measurements proved, however, that the entropy value for Mg-exchanged A-type zeolite is so small, even at the ambient temperature, as to be compared with the residual entropy of ice at 0 K.
Abstract
Heat capacity and enthalpy increments of calcium niobates CaNb2O6 and Ca2Nb2O7 were measured by the relaxation time method (2–300 K), DSC (260–360 K) and drop calorimetry (669–1421 K). Temperature dependencies of the molar heat capacity in the form C pm=200.4+0.03432T−3.450·106/T 2 J K−1 mol−1 for CaNb2O6 and C pm=257.2+0.03621T−4.435·106/T 2 J K−1 mol−1 for Ca2Nb2O7 were derived by the least-squares method from the experimental data. The molar entropies at 298.15 K, S m 0(CaNb2O6, 298.15 K)=167.3±0.9 J K−1 mol−1 and S m 0(Ca2Nb2O7, 298.15 K)=212.4±1.2 J K−1 mol−1, were evaluated from the low temperature heat capacity measurements. Standard enthalpies of formation at 298.15 K were derived using published values of Gibbs energy of formation and presented heat capacity and entropy data: Δf H 0(CaNb2O6, 298.15 K)= −2664.52 kJ molt-1 and Δf H 0(Ca2Nb2O7, 298.15 K)= −3346.91 kJ mol−1.
References [1] A . Artigue , D . Carrasco-Oliveira and I . Monteverde . Polynomial entropy and expansivity . Acta Mathematica Hungarica , 152 : 140 – 149 , 2017 . [2] P . Bernard and C . Labrousse . An entropic characterization on the
Summary As part of a larger study of the physical properties of potential ceramic hosts for nuclear wastes, we report the molar heat capacity of brannerite (UTi2O6) and its cerium analog (CeTi2O6) from 10 to 400 K using an adiabatic calorimeter. At 298.15 K the standard molar heat capacities are (179.46±0.18) J K-1 mol-1 for UTi2O6 and (172.78±0.17) J K-1 mol-1 for CeTi2O6. Entropies were calculated from smooth fits of the experimental data and were found to be (175.56±0.35) J K-1 mol-1 and (171.63±0.34) J K-1 mol-1 for UTi2O6 and CeTi2O6, respectively. Using these entropies and enthalpy of formation data reported in the literature, Gibb’s free energies of formation from the elements and constituent oxides were calculated. Standard free energies of formation from the elements are (-2814.7±5.6) kJ mol-1 for UTi2O6 and (-2786.3±5.6) kJ mol-1 for CeTi2O6. The free energy of formation from the oxides at T=298.15 K are (-5.31±0.01) kJ mol-1 and (15.88±0.03) kJ mol-1 for UTi2O6 and CeTi2O6, respectively.
like term which we shall call exergy, X = iC , where i is a measure of quality, expressed as the ratio of total citations C to total papers published P . The thermodynamic paradigm leads further to concepts of energy ( E ), and entropy ( S
Abstract
The non-equilibrium process due to irreversible heat exchanges occurring during a temperature modulated differential scanning calorimetry (TMDSC) experiment is investigated in detail. This enables us to define an experimental frequency dependent complex heat capacity from this calorimetric method. The physical meaning of this dynamic heat capacity is discussed. A relationship is clearly established between the imaginary part of this complex quantity and the net entropy created during the experimental time-scale.
Aziz, W., Arif, M. (2006) Complexity analysis of stride interval time series by threshold dependent symbolic entropy. Eur. J. Appl. Physiol. 98, 30–40. Arif M. Complexity analysis
Abstract
Relative entropy between two quantum states, which quantifies to what extent the quantum states can be distinguished via whatever methods allowed by quantum mechanics, is a central and fundamental quantity in quantum information theory. However, in both theoretical analysis (such as selective measurements) and practical situations (such as random experiments), one is often encountered with quantum ensembles, which are families of quantum states with certain prior probability distributions. How can we quantify the quantumness and distinguishability of quantum ensembles? In this paper, by use of a probabilistic coupling technique, we propose a notion of relative entropy between quantum ensembles, which is a natural generalization of the relative entropy between quantum states. This generalization enjoys most of the basic and important properties of the original relative entropy. As an application, we use the notion of relative entropy between quantum ensembles to define a measure for quantumness of quantum ensembles. This quantity may be useful in quantum cryptography since in certain circumstances it is desirable to encode messages in quantum ensembles which are the most quantum, thus the most sensitive to eavesdropping. By use of this measure of quantumness, we demonstrate that a set consisting of two pure states is the most quantum when the states are 45° apart.
Abstract
The Bregman operator divergence is introduced for density matrices by differentiation of the matrix-valued function x ↦ x log x. This quantity is compared with the relative operator entropy of Fujii and Kamei. It turns out that the trace is the usual Umegaki’s relative entropy which is the only intersection of the classes of quasi-entropies and Bregman divergences.
