Experimental Data and Modeling of Solution Density and Heat Capacity in the Na–K–Ca–Mg–Cl–H2O System up to 353.15 K and 5 mol·kg–1Ionic Strength

2017 ◽  
Vol 62 (10) ◽  
pp. 3561-3576 ◽  
Author(s):  
Adeline Lach ◽  
Karine Ballerat-Busserolles ◽  
Laurent André ◽  
Mickaël Simond ◽  
Arnault Lassin ◽  
...  
Keyword(s):  
Experimental Data ◽  
Heat Capacity ◽  
Solution Density

scholarly journals Calculation of the Isobaric Heat Capacities of the Liquid and Solid Phase of Organic Compounds at 298.15K by Means of the Group-Additivity Method

Molecules ◽  
2020 ◽  
Vol 25 (5) ◽  
pp. 1147
Author(s):  
Rudolf Naef
Keyword(s):  
Experimental Data ◽  
Heat Capacity ◽  
Goodness Of Fit ◽  
Cross Validation ◽  
Solid Phase ◽  
Linear Equations ◽  
Heat Capacities ◽  
Molecular Volume ◽  
Complementary Method ◽  
Standard Deviations

The calculation of the isobaric heat capacities of the liquid and solid phase of molecules at 298.15 K is presented, applying a universal computer algorithm based on the atom-groups additivity method, using refined atom groups. The atom groups are defined as the molecules’ constituting atoms and their immediate neighbourhood. In addition, the hydroxy group of alcohols are further subdivided to take account of the different intermolecular interactions of primary, secondary, and tertiary alcohols. The evaluation of the groups’ contributions has been carried out by solving a matrix of simultaneous linear equations by means of the iterative Gauss–Seidel balancing calculus using experimental data from literature. Plausibility has been tested immediately after each fitting calculation using a 10-fold cross-validation procedure. For the heat capacity of liquids, the respective goodness of fit of the direct (r2) and the cross-validation calculations (q2) of 0.998 and 0.9975, and the respective standard deviations of 8.24 and 9.19 J/mol/K, together with a mean absolute percentage deviation (MAPD) of 2.66%, based on the experimental data of 1111 compounds, proves the excellent predictive applicability of the present method. The statistical values for the heat capacity of solids are only slightly inferior: for r2 and q2, the respective values are 0.9915 and 0.9874, the respective standard deviations are 12.21 and 14.23 J/mol/K, and the MAPD is 4.74%, based on 734 solids. The predicted heat capacities for a series of liquid and solid compounds have been directly compared to those received by a complementary method based on the "true" molecular volume and their deviations have been elucidated.

scholarly journals Thermodynamics of Uranium Tri-Iodide from Density-Functional Theory

2020 ◽  
Vol 10 (11) ◽  
pp. 3914
Author(s):  
Per Söderlind ◽  
Aurélien Perron ◽  
Emily E. Moore ◽  
Alexander Landa ◽  
Tae Wook Heo
Keyword(s):  
Experimental Data ◽  
Density Functional Theory ◽  
Heat Capacity ◽  
Density Functional ◽  
Thermodynamic Assessment ◽  
Harmonic Approximation ◽  
Metallic System ◽  
Generalized Gradient ◽  
Functional Theory ◽  
Generalized Gradient Approximation

Density-functional theory (DFT) is employed to investigate the thermodynamic and ground-state properties of bulk uranium tri-iodide, UI3. The theory is fully relativistic and electron correlations, beyond the DFT and generalized gradient approximation, are addressed with orbital polarization. The electronic structure indicates anti-ferromagnetism, in agreement with neutron diffraction, with band gaps and a non-metallic system. Furthermore, the formation energy, atomic volume, crystal structure, and heat capacity are calculated in reasonable agreement with experiments, whereas for the elastic constants experimental data are unavailable for comparison. The thermodynamical properties are modeled within a quasi-harmonic approximation and the heat capacity and Gibbs free energy as functions of temperature agree with available calculation of phase diagram (CALPHAD) thermodynamic assessment of the experimental data.

Forced Convection Heat Transfer of Nanofluids: A Review

2017 ◽  
Author(s):  
Aditya Kuchibhotla ◽  
Debjyoti Banerjee
Keyword(s):  
Heat Transfer ◽  
Experimental Data ◽  
Thermal Conductivity ◽  
Heat Capacity ◽  
Heat Transfer Coefficient ◽  
Transfer Coefficient ◽  
Specific Heat ◽  
Forced Convection ◽  
Convection Heat Transfer ◽  
Convection Heat

Stable homogeneous colloidal suspensions of nanoparticles in a liquid solvents are termed as nanofluids. In this review the results for the forced convection heat transfer of nanofluids are gleaned from the literature reports. This study attempts to evaluate the experimental data in the literature for the efficacy of employing nanofluids as heat transfer fluids (HTF) and for Thermal Energy Storage (TES). The efficacy of nanofluids for improving the performance of compact heat exchangers were also explored. In addition to thermal conductivity and specific heat capacity the rheological behavior of nanofluids also play a significant role for various applications. The material properties of nanofluids are highly sensitive to small variations in synthesis protocols. Hence the scope of this review encompassed various sub-topics including: synthesis protocols for nanofluids, materials characterization, thermo-physical properties (thermal conductivity, viscosity, specific heat capacity), pressure drop and heat transfer coefficients under forced convection conditions. The measured values of heat transfer coefficient of the nanofluids varies with testing configuration i.e. flow regime, boundary condition and geometry. Furthermore, a review of the reported results on the effects of particle concentration, size, temperature is presented in this study. A brief discussion on the pros and cons of various models in the literature is also performed — especially pertaining to the reports on the anomalous enhancement in heat transfer coefficient of nanofluids. Furthermore, the experimental data in the literature indicate that the enhancement observed in heat transfer coefficient is incongruous compared to the level of thermal conductivity enhancement obtained in these studies. Plausible explanations for this incongruous behavior is explored in this review. A brief discussion on the applicability of conventional single phase convection correlations based on Newtonian rheological models for predicting the heat transfer characteristics of the nanofluids is also explored in this review (especially considering that nanofluids often display non-Newtonian rheology). Validity of various correlations reported in the literature that were developed from experiments, is also explored in this review. These comparisons were performed as a function of various parameters, such as, for the same mass flow rate, Reynolds number, mass averaged velocity and pumping power.

The heat capacity of Ni3Fe: experimental data from 300 to 1670 K

1973 ◽  
Vol 19 (2) ◽  
pp. 545-554 ◽  
Author(s):  
T. G. Kollie ◽  
C. R. Brooks
Keyword(s):  
Experimental Data ◽  
Heat Capacity

scholarly journals Review of existing and development of a novel mathematical model for supercritical CO2 cycles working fluid

2018 ◽  
Vol 240 ◽  
pp. 01036
Author(s):  
Marcin Wołowicz ◽  
Jarosław Milewski ◽  
Piotr Lis
Keyword(s):  
Experimental Data ◽  
Carbon Dioxide ◽  
Mathematical Model ◽  
Heat Capacity ◽  
Supercritical Co2 ◽  
Pressure Range ◽  
Critical Conditions ◽  
Working Fluid ◽  
Critical Properties ◽  
Area Of Interest

The paper aims to compare the models of working fluids against experimental data for carbon dioxide close to its critical conditions. Fortunately, most of the work is already done and published where the authors compared the models based on the equation of the state (EoS). There are a few other models which were not investigated, thus we would like to add a few new results here and focus only on near-critical properties where the biggest deviation between experimental and calculated properties can be observed. The area of interest was pressure range of 7.39 – 20 MPa and temperature range of 304-340 K just above fluid critical point (7.39 MPa, 304.25 K). Model validation was performed for density and heat capacity as one of the most important parameters in preliminary cycle analysis.

Ultrasonic Investigations of Inclusion Complexation of α-Cyclodextrin by DMSO in Pseudo-Binary Aqueous System

2015 ◽  
Vol 40 (4) ◽  
pp. 569-574
Author(s):  
Milena Kaczmarek-Klinowska ◽  
Tomasz Hornowski ◽  
Andrzej Skumiel ◽  
Monika Jażdżewska
Keyword(s):  
Experimental Data ◽  
Aqueous Solution ◽  
Heat Capacity ◽  
Inclusion Complexation ◽  
Adiabatic Compressibility ◽  
Resonance Method ◽  
Molecular Complexes ◽  
Aqueous System ◽  
Ultrasonic Waves ◽  
Stoichiometric Ratio

Abstract The paper reports the study of the complexation processes in aqueous solution of α-CD and DMSO. Cyclodextrins (CDs) (sometimes called cycloamyloses) are cyclic oligosaccharides formed by glucose units interconnected by α-(1,4) linkages; α-CD is one of three the most common CDs. It consists of six glucopyranose units. The speed of ultrasonic waves has been measured by the resonance method on ResoscanTM System apparatus. Some collateral data, such as density and heat capacity of the system, have also been measured. On the basis of the experimental data the excess adiabatic compressibility was determined. The extremes of the excess adiabatic compressibility function for different mixture compositions allowed us to establish the composition of molecular complexes formed in the solution. The obtained results suggest the formation of the α-CD with DMSO inclusion complexes with chemical stoichiometric ratio value of 1:1.

Pressure rise generated by the expansion of a local gas volume in a closed vessel

2009 ◽  
Vol 465 (2112) ◽  
pp. 3627-3646 ◽  
Author(s):  
Douglas Stamps ◽  
Edward Cooper ◽  
Ryan Egbert ◽  
Steve Heerdink ◽  
Valerie Stringer
Keyword(s):  
Experimental Data ◽  
Heat Capacity ◽  
Volume Fraction ◽  
Pressure Rise ◽  
Initial Pressure ◽  
Inert Gas ◽  
Closed Vessel ◽  
Gas Combustion ◽  
Gas Volume ◽  
Theoretical Results

Experiments were conducted to determine the pressure rise that results from either the combustion of a localized gas volume or the expansion of a pressurized gas volume adjacent to an inert gas in a closed vessel. The experiments consisted of either pressurized air or the combustion of stoichiometric and fuel-lean hydrogen–air mixtures compressing an inert gas. The pressure rise in the inert gas was measured as a function of either the volume fraction or the initial pressure of the expanding gas. Helium, nitrogen, air and carbon dioxide were tested to explore the effect of inert gas heat capacity on the pressure rise. The final pressure of the inert gas increased with the volume fraction and initial pressure of the expanding gas, and was influenced to a lesser extent by the heat capacity of the inert gas. A model was assessed using the experimental data, and the theoretical results were consistent with the observed trends. This model and other published models were assessed and compared using prior data for localized gas combustion surrounded by an inert gas and the partial combustion of homogeneous methane–air mixtures.

First-Principles Calculations of Elastic and Thermodynamic Properties of Cubic CdTe

2011 ◽  
Vol 268-270 ◽  
pp. 886-891
Author(s):  
Ben Hai Yu ◽  
Dong Chen
Keyword(s):  
Experimental Data ◽  
Heat Capacity ◽  
Thermodynamic Properties ◽  
Bulk Modulus ◽  
First Principles ◽  
Debye Model ◽  
First Principles Calculations ◽  
Lattice Constants ◽  
Temperature And Pressure ◽  
The Relationship

the equilibrium lattice constants, elastic and thermodynamic properties of cubic CdTe are systemically investigated at high temperature using the plane-wave pseudopotential method as well as the quasi-harmonic Debye model. The bulk modulus of CdTe are calculated as a function of temperature up to 1000K, the relationship between bulk modulusBand pressure is also obtained. The results gained from this model will provide overall predictions accurately for the temperature and pressure dependence of various quantities such as the bulk modulus, the heat capacity and the thermal expansion coefficient. More over, the dependences between Debye temperature and temperature are also successfully obtained. Our results are compared with the experimental data and discussed in light of previous works.

Comparative study between exponential Boltzmann and Lambert Boltzmann distributions for heat capacity calculation

2019 ◽  
Vol 33 (14) ◽  
pp. 1950140
Author(s):  
Chokri Hadj Belgacem
Keyword(s):  
Experimental Data ◽  
Heat Capacity ◽  
Comparative Study ◽  
Excellent Agreement ◽  
Boltzmann Distribution ◽  
Lambert W Function ◽  
Stirling Formula ◽  
Analytical Formulation ◽  
Semiconductor Compounds ◽  
Capacity Calculation

The Stirling’s estimation to [Formula: see text](N!) is typically introduced to students as a step in the derivation of the statistical expression for the heat capacity. However, naïve application of this estimation leads to wrong conclusions. In this paper, firstly, the heat capacity of some semiconductor compounds was calculated using exponential Boltzmann distribution and compared with experimental data. It has shown a disagreement between experimental results and those calculated. Secondly, by applying the more exact Stirling formula, an analytical formulation of Boltzmann statistics using Lambert W function is shown to be a very good model and proves an excellent agreement between calculated and experimental data for heat capacity over the entire temperature range.

THERMODYNAMIC PROPERTIES OF MC (M = V, Nb, Ta): FIRST-PRINCIPLES CALCULATIONS

2013 ◽  
Vol 27 (19) ◽  
pp. 1341035 ◽  
Author(s):  
YONG CAO ◽  
JINGCHUAN ZHU ◽  
YONG LIU ◽  
ZHISHEN LONG
Keyword(s):  
Experimental Data ◽  
Heat Capacity ◽  
Thermodynamic Properties ◽  
Bulk Modulus ◽  
First Principles ◽  
Linear Expansion ◽  
Debye Model ◽  
Linear Expansion Coefficient ◽  
First Principles Calculations ◽  
Temperature Dependences

Through the quasi-harmonic Debye model, the pressure and temperature dependences of linear expansion coefficient, bulk modulus, Debye temperature and heat capacity have been investigated. The calculated thermodynamic properties were compared with experimental data and satisfactory agreement is reached.

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