The Experts below are selected from a list of 12546 Experts worldwide ranked by ideXlab platform
Ryo Akasaka - One of the best experts on this subject based on the ideXlab platform.
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the precise measurement of vapor liquid equilibrium properties of the co _ isopentane binary mixture and fitted parameters for a helmholtz energy mixture model
International Journal of Thermophysics, 2017Co-Authors: H Miyamoto, Ryo Akasaka, Y. Shoji, Eric W LemmonAbstract:Natural working fluid mixtures, including combinations of CO\(_{2}\), hydrocarbons, water, and ammonia, are expected to have applications in energy conversion processes such as heat pumps and organic Rankine cycles. However, the available literature data, much of which were published between 1975 and 1992, do not incorporate the recommendations of the Guide to the Expression of Uncertainty in Measurement. Therefore, new and more reliable Thermodynamic Property measurements obtained with state-of-the-art technology are required. The goal of the present study was to obtain accurate vapor–liquid equilibrium (VLE) properties for complex mixtures based on two different gases with significant variations in their boiling points. Precise VLE data were measured with a recirculation-type apparatus with a 380 cm\(^{3}\) equilibration cell and two windows allowing observation of the phase behavior. This cell was equipped with recirculating and expansion loops that were immersed in temperature-controlled liquid and air baths, respectively. Following equilibration, the composition of the sample in each loop was ascertained by gas chromatography. VLE data were acquired for CO\(_{2}\)/ethanol and CO\(_{2}\)/isopentane binary mixtures within the temperature range from 300 K to 330 K and at pressures up to 7 MPa. These data were used to fit interaction parameters in a Helmholtz energy mixture model. Comparisons were made with the available literature data and values calculated by Thermodynamic Property models.
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a Thermodynamic Property model for the r 134a 245fa mixture
2014 Purdue Conferences. 15th International Refrigeration and Air-Conditioning Conference at Purdue., 2014Co-Authors: Ryo Akasaka, Yukihiro HigashiAbstract:A Thermodynamic Property model explicit in the Helmholtz energy is presented for the R-134a/245fa mixtures. A multi-fluid approximation based on pure-fluid Helmholtz energy equations of state forms the basis of the Property model. The Helmholtz energy of the mixture is expressed as the sum of the ideal gas contribution, the compressibility contribution (real fluid contribution), and the contribution from mixing to represent the deviation from ideal mixtures. The independent variables are the temperature, molar volume, and composition. The model can be used to calculate all Thermodynamic properties of the mixtures at various compositions. The estimated uncertainties in calculated properties from the model are ±0.2 % for the bubble and dew point pressures and ±0.24 % for the liquid and vapor densities. The critical parameters of the mixtures are properly represented with the model. The calculated critical temperatures correspond to experimental values within ±0. 5K .
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Thermodynamic Property models for the difluoromethane r 32 trans 1 3 3 3 tetrafluoropropene r 1234ze e and difluoromethane 2 3 3 3 tetrafluoropropene r 1234yf mixtures
Fluid Phase Equilibria, 2013Co-Authors: Ryo AkasakaAbstract:Abstract Thermodynamic Property models explicit in the Helmholtz energy are presented for the R-32/1234ze(E) and R-32/1234yf mixtures. The Helmholtz energy of the mixtures are expressed as the sum of the ideal mixture contribution and the contribution from mixing. The independent variables are the temperature, molar volume, and composition. The most accurate pure-fluid equations of state are incorporated to calculate the ideal mixture contribution. The contribution from mixing is determined by fitting to available experimental data. The estimated uncertainties in calculated properties from the models are 1% for the bubble point pressure and 0.25% for liquid density. The critical loci of the mixtures are reasonably represented with the models. The calculated critical temperatures correspond to experimental values within ±0.8 K.
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an application of the extended corresponding states model to Thermodynamic Property calculations for trans 1 3 3 3 tetrafluoropropene hfo 1234ze e
International Journal of Refrigeration-revue Internationale Du Froid, 2010Co-Authors: Ryo AkasakaAbstract:Abstract A new Thermodynamic Property model is presented for trans-1,3,3,3-tetrafluoropropene (trans-CHF CHCF3, HFO-1234ze(E)) based upon available experimental data. This model is an application of the extended corresponding states principle, which is one approach in Property modeling for fluids with limited experimental databases. The model is capable of calculating with reasonable accuracies various properties of HFO-1234ze(E), including the PVT relation, energies, heat capacities, and vapor–liquid equilibrium. The reference fluid of the model is 1,1,1,2-tetrafluoroethane (HFC-134a). Comparisons of calculated values using the model are made with experimental data. Typical uncertainties of calculated properties are 0.2% in the vapor pressure, 0.5% in the liquid density, and 5% in the liquid and vapor isobaric heat capacities. In addition, an ancillary equation is given for the vapor pressure. Thermodynamic Property diagrams generated using the model are also provided.
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Thermodynamic Property modeling for 2 3 3 3 tetrafluoropropene hfo 1234yf
International Journal of Refrigeration-revue Internationale Du Froid, 2010Co-Authors: Ryo Akasaka, Katsuyuki Tanaka, Yukihiro HigashiAbstract:Abstract This paper presents a timely and reliable equation of state for 2,3,3,3-tetrafluoropropene (HFO-1234yf) whose Thermodynamic Property information is strongly desired. The Patel–Teja (PT) equation of state and the extended corresponding state (ECS) model have been individually applied to Property modeling for this new refrigerant. Comparisons of predicted values with the equation/model were made with the most recent experimental data. Both the PT equation of state and the ECS model can represent the vapor pressures with an accuracy of 0.2%. However, the ECS model is much better than the PT equation of state in the predictions for the liquid density and isobaric heat capacity. The uncertainties of calculated values with the ECS model are 0.5% in liquid density and 2.5% in isobaric heat capacity. The use of the ECS model is recommended for a detailed assessment of HFO-1234yf. Thermodynamic Property tables and diagrams generated using the ECS model are provided.
Bidyut Baran Saha - One of the best experts on this subject based on the ideXlab platform.
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Thermodynamic Property surfaces for various adsorbent adsorbate pairs for cooling applications
International Journal of Heat and Mass Transfer, 2019Co-Authors: Tahmid Hasan Rupam, Anutosh Chakraborty, Bidyut Baran Saha, Md Amirul Islam, Animesh PalAbstract:Abstract This study focuses on comparative analysis of five different adsorbent/adsorbate pairs regarding Thermodynamic Property fields based on some well-established mathematical modelling. The Thermodynamic Property fields such as enthalpy (h), entropy (s) are expressed in terms of temperature, pressure and adsorbed quantity. Moreover, the isosteric heat of adsorption for pairs having a common adsorbent with the three different refrigerants were compared to investigate the effect of adsorbate molecules on the isosteric heat of adsorption. T-s diagrams are analyzed for all the five pairs for different cooling conditions: 5 °C, 10 °C and 15 °C. This information along with the isotherms and kinetics data find immense importance in the computation of energy balances of the adsorbed phase. These results are crucial for rigorous design and analysis of adsorption cooling systems.
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adsorption characteristics and Thermodynamic Property fields of polymerized ionic liquid and polyvinyl alcohol based composite co2 pairs
Journal of Molecular Liquids, 2019Co-Authors: Bidyut Baran Saha, Animesh Pal, Kaiser Ahmed Rocky, Muhammad MoniruzzamanAbstract:Abstract Consolidated composites are strongly considered as promising adsorbents for adsorption cooling system (ACS) applications. Binder plays a vital role to synthesize consolidated composite. In this study, consolidated composites are synthesized employing highly porous activated carbon (AC) namely Maxsorb III and two types of binders: (i) polymerized ionic liquid (PIL) and (ii) polyvinyl alcohol (PVA) for the development of compact CO2 based ACS. Adsorption characteristics of composite/CO2 pairs are studied at temperature ranging from 20 to 70 °C and pressure up to 7000 kPa. Experimental adsorption uptake data are fitted with Langmuir, Toth, Dubinin-Astakhov (D-A) and modified D-A equations. It is observed that composite employing 90 wt% Maxsorb III and 10 wt% PIL shows maximum CO2 adsorption uptake of 1.41146 cm3 g−1, whilst composite incorporating 90 wt% Maxsorb III and 10 wt% PVA can adsorb up to 1.31311 cm3 g−1. Besides, the adsorption/desorption kinetics and Thermodynamic properties such as isosteric heat of adsorption, specific heat capacity, entropy and enthalpy, which are very crucial for ACS design, are rigorously analyzed here.
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Thermodynamic Property slopes from primary measurements
The International journal of mechanical engineering education, 2012Co-Authors: Bidyut Baran Saha, Kandadai Srinivasan, Pradip Dutta, Michael J BrearAbstract:This paper lists the values of slope properties of entropy, enthalpy and exergy along isotherms, isochors, isobars and isentropes in terms of properties that can be primarily measured, namely pressure, volume, temperature, their slopes derivable from equations of state and one of the specific heats in the ideal gas state. It is also shown that all these slopes can be expressed in terms of a coefficient of thermal expansion and isothermal compressibility as well. These could be useful as an educational tool in chemical and mechanical engineering.
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Thermodynamic Property surfaces for adsorption of r507a r134a and n butane on pitch based carbonaceous porous materials
Heat Transfer Engineering, 2010Co-Authors: Anutosh Chakraborty, Bidyut Baran Saha, Ibrahim I Elsharkawy, Shigeru KoyamaAbstract:The Thermodynamic Property surfaces of R507A, R134a, and n-butane on pitch-based carbonaceous porous material (Maxsorb III) are developed from rigorous classical Thermodynamics and experimentally measured adsorption isotherm data. These Property fields enable us to compute the entropy, enthalpy, internal energy, and heat of adsorption as a function of pressure, temperature, and the amount of adsorbate. The entropy and enthalpy maps are necessary for the analysis of adsorption cooling cycle and gas storage. We have shown here that it is possible to plot an adsorption cooling cycle on the temperature-entropy (T–s) and enthalpy-uptake (h–x) maps.
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theoretical insight of physical adsorption for a single component adsorbent adsorbate system i Thermodynamic Property surfaces
Langmuir, 2009Co-Authors: Anutosh Chakraborty, Bidyut Baran Saha, Shigeru Koyama, Kandadai SrinivasanAbstract:Thermodynamic Property surfaces for a single-component adsorbent + adsorbate system are derived and developed from the viewpoint of classical Thermodynamics, Thermodynamic requirements of chemical equilibrium, Gibbs law, and Maxwell relations. They enable us to compute the entropy and enthalpy of the adsorbed phase, the isosteric heat of adsorption, specific heat capacity, and the adsorbed phase volume thoroughly. These equations are very simple and easy to handle for calculating the energetic performances of any adsorption system. We have shown here that the derived Thermodynamic formulations fill up the information gap with respect to the state of adsorbed phase to dispel the confusion as to what is the actual state of the adsorbed phase. We have also discussed and established the temperature-entropy diagrams of (i) CaCl2-in-silica gel + water system for cooling applications, and (ii) activated carbon (Maxsorb III) + methane system for gas storage.
Yukihiro Higashi - One of the best experts on this subject based on the ideXlab platform.
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a Thermodynamic Property model for the r 134a 245fa mixture
2014 Purdue Conferences. 15th International Refrigeration and Air-Conditioning Conference at Purdue., 2014Co-Authors: Ryo Akasaka, Yukihiro HigashiAbstract:A Thermodynamic Property model explicit in the Helmholtz energy is presented for the R-134a/245fa mixtures. A multi-fluid approximation based on pure-fluid Helmholtz energy equations of state forms the basis of the Property model. The Helmholtz energy of the mixture is expressed as the sum of the ideal gas contribution, the compressibility contribution (real fluid contribution), and the contribution from mixing to represent the deviation from ideal mixtures. The independent variables are the temperature, molar volume, and composition. The model can be used to calculate all Thermodynamic properties of the mixtures at various compositions. The estimated uncertainties in calculated properties from the model are ±0.2 % for the bubble and dew point pressures and ±0.24 % for the liquid and vapor densities. The critical parameters of the mixtures are properly represented with the model. The calculated critical temperatures correspond to experimental values within ±0. 5K .
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Thermodynamic Property modeling for 2 3 3 3 tetrafluoropropene hfo 1234yf
International Journal of Refrigeration-revue Internationale Du Froid, 2010Co-Authors: Ryo Akasaka, Katsuyuki Tanaka, Yukihiro HigashiAbstract:Abstract This paper presents a timely and reliable equation of state for 2,3,3,3-tetrafluoropropene (HFO-1234yf) whose Thermodynamic Property information is strongly desired. The Patel–Teja (PT) equation of state and the extended corresponding state (ECS) model have been individually applied to Property modeling for this new refrigerant. Comparisons of predicted values with the equation/model were made with the most recent experimental data. Both the PT equation of state and the ECS model can represent the vapor pressures with an accuracy of 0.2%. However, the ECS model is much better than the PT equation of state in the predictions for the liquid density and isobaric heat capacity. The uncertainties of calculated values with the ECS model are 0.5% in liquid density and 2.5% in isobaric heat capacity. The use of the ECS model is recommended for a detailed assessment of HFO-1234yf. Thermodynamic Property tables and diagrams generated using the ECS model are provided.
Kazuki Morita - One of the best experts on this subject based on the ideXlab platform.
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phase relations and Thermodynamic Property of boron in the silicon tin melt at 1673 k
Journal of Alloys and Compounds, 2012Co-Authors: Takeshi Yoshikawa, Kazuki MoritaAbstract:Abstract In order to optimize the removal of B during the Si refining process using a Si–Sn solvent, Thermodynamic Property of B in the melt is crucial. In this study, the isothermal section for the Si–Sn–B system at 1673 K was measured by the equilibration of the liquid phase with B solid solution or silicon boride. The activity coefficient of B in the Si–Sn melt at 1673 K was evaluated, which was found to be three orders of magnitude larger in the Sn-rich side than that in the Si-rich side. This result suggests the removal of B can be achieved easily from the Si–Sn melt with the larger Sn content.
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Thermodynamic Property of b in molten si and phase relations in the si al b system
Materials Transactions, 2005Co-Authors: Takeshi Yoshikawa, Kazuki MoritaAbstract:Department of Materials Engineering, Graduate School of Engineering, The University of Tokyo, Tokyo 113-8656, Japan The Thermodynamic Property of B in molten Si, which is of importance for optimizing or designing the B removal process from Si, was determined as the following equation by equilibrating molten Si with Si 3 N 4 and BN at 1693 and 1773 K. In γ B ( i ) i n m o l t e n S i = 1.19(′0.25) + 289(′450) T (1693-1923 K) Also, the standard Gibbs energy change for N 2 dissolution into molten Si was determined as the following equation. ½ N 2 (g) = N(mass%, in molten Si) ΔG' = -36,200(′23,500)+39.8(′13.6)T (J/mol) (1693-1773 K) On the other hand, to understand the B behavior in the solidification refining of Si with Si-Al melt, phase relations in the Si-Al-B system were investigated at 1373-1573 K. The boride in equilibrium with Si-Al melt was clarified as AlB 1 2 solid solution and the Thermodynamic Property of that solid solution was discussed.
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Thermodynamic Property of b in molten si and phase relations in the si al b system
Materials Transactions, 2005Co-Authors: Takeshi Yoshikawa, Kazuki MoritaAbstract:Department of Materials Engineering, Graduate School of Engineering, The University of Tokyo, Tokyo 113-8656, Japan The Thermodynamic Property of B in molten Si, which is of importance for optimizing or designing the B removal process from Si, was determined as the following equation by equilibrating molten Si with Si 3 N 4 and BN at 1693 and 1773 K. In γ B ( i ) i n m o l t e n S i = 1.19(′0.25) + 289(′450) T (1693-1923 K) Also, the standard Gibbs energy change for N 2 dissolution into molten Si was determined as the following equation. ½ N 2 (g) = N(mass%, in molten Si) ΔG' = -36,200(′23,500)+39.8(′13.6)T (J/mol) (1693-1773 K) On the other hand, to understand the B behavior in the solidification refining of Si with Si-Al melt, phase relations in the Si-Al-B system were investigated at 1373-1573 K. The boride in equilibrium with Si-Al melt was clarified as AlB 1 2 solid solution and the Thermodynamic Property of that solid solution was discussed.
Kandadai Srinivasan - One of the best experts on this subject based on the ideXlab platform.
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Thermodynamic Property slopes from primary measurements
The International journal of mechanical engineering education, 2012Co-Authors: Bidyut Baran Saha, Kandadai Srinivasan, Pradip Dutta, Michael J BrearAbstract:This paper lists the values of slope properties of entropy, enthalpy and exergy along isotherms, isochors, isobars and isentropes in terms of properties that can be primarily measured, namely pressure, volume, temperature, their slopes derivable from equations of state and one of the specific heats in the ideal gas state. It is also shown that all these slopes can be expressed in terms of a coefficient of thermal expansion and isothermal compressibility as well. These could be useful as an educational tool in chemical and mechanical engineering.
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theoretical insight of physical adsorption for a single component adsorbent adsorbate system i Thermodynamic Property surfaces
Langmuir, 2009Co-Authors: Anutosh Chakraborty, Bidyut Baran Saha, Shigeru Koyama, Kandadai SrinivasanAbstract:Thermodynamic Property surfaces for a single-component adsorbent + adsorbate system are derived and developed from the viewpoint of classical Thermodynamics, Thermodynamic requirements of chemical equilibrium, Gibbs law, and Maxwell relations. They enable us to compute the entropy and enthalpy of the adsorbed phase, the isosteric heat of adsorption, specific heat capacity, and the adsorbed phase volume thoroughly. These equations are very simple and easy to handle for calculating the energetic performances of any adsorption system. We have shown here that the derived Thermodynamic formulations fill up the information gap with respect to the state of adsorbed phase to dispel the confusion as to what is the actual state of the adsorbed phase. We have also discussed and established the temperature-entropy diagrams of (i) CaCl2-in-silica gel + water system for cooling applications, and (ii) activated carbon (Maxsorb III) + methane system for gas storage.
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improved Thermodynamic Property fields of libr h2o solution
International Journal of Refrigeration-revue Internationale Du Froid, 2000Co-Authors: Hui Tong Chua, H K Toh, A Malek, Kandadai SrinivasanAbstract:This article presents a Thermodynamically consistent set of specific enthalpy, entropy, and heat capacity fields for LiBr-$H_2O$ solution. The temperatures span from 0 to $190^oC$, while the concentrations span from 0 to 75 wt%. The work is based on the empirical inputs of Duhring's gradient and intercept, specific heat capacity data at a reference concentration of 50 wt% and density data. These properties have been evaluated using most of the experimental data available in the literature. The present approach circumvents the issue of negative dew point at low temperatures and high concentrations. The information provided in this article could be useful for designers of absorption chillers.