The Experts below are selected from a list of 360 Experts worldwide ranked by ideXlab platform
Long-qing Chen - One of the best experts on this subject based on the ideXlab platform.
-
a Thermodynamic Potential energy storage performances and electrocaloric effects of ba1 xsrxtio3 single crystals
Applied Physics Letters, 2018Co-Authors: Yu Hui Huang, Junjie Wang, Tiannan Yang, X M Chen, Long-qing ChenAbstract:A Thermodynamic Potential for Ba1-xSrxTiO3 solid solutions is developed, and the corresponding Thermodynamic properties of Ba1-xSrxTiO3 single crystals are calculated. The predicted temperature-composition phase diagram from the Thermodynamic Potential agrees well with the experimental measurements. Based on this Potential, the energy storage performances and electrocaloric effects of Ba1-xSrxTiO3 single crystals are obtained using the phase-field method. It is found that there is an optimal Sr concentration which maximizes the discharged energy density of a Ba1-xSrxTiO3 single crystal under an applied electric field. The electrocaloric effects of Ba0.8Sr0.2TiO3, Ba0.7Sr0.3TiO3, Ba0.6Sr0.4TiO3, and Ba0.5Sr0.5TiO3 single crystals are also predicted, from which the corresponding optimal temperatures are identified.
-
Thermodynamic Potential and phase diagram for multiferroic bismuth ferrite (BiFeO 3 )
npj Computational Materials, 2017Co-Authors: Dmitry V. Karpinsky, Eugene A. Eliseev, Fei Xue, Maxim V. Silibin, Alexandra Franz, Maya D. Glinchuk, I. O. Troyanchuk, Sergey Gavrilov, Venkatraman Gopalan, Long-qing ChenAbstract:We construct a Landau–Ginzburg Thermodynamic Potential, and the corresponding phase diagram for pristine and slightly doped bismuth ferrite, a ferroelectric antiferromagnet at room temperature. The Potential is developed based on new X-ray and neutron diffraction experiments complementing available data. We demonstrate that a strong biquadratic antiferrodistortive-type coupling is the key to a quantitative description of Bi1−x La x FeO3 multiferroic phase diagram including the temperature stability of the antiferromagnetic, ferroelectric, and antiferrodistortive phases, as well as for the prediction of novel intermediate structural phases. Furthermore, we show that “rotomagnetic” antiferrodistortive–antiferromagnetic coupling is very important to describe the ferroelectric polarization and antiferrodistortive tilt behavior in the R3c phase of BiFeO3. The Landau–Ginzburg Thermodynamic Potential is able to describe the sequence of serial and trigger-type phase transitions, the temperature-dependent behavior of the order parameters, and the corresponding susceptibilities to external stimuli. It can also be employed to predict the corresponding ferroelectric and antiferrodistortive properties of Bi1−x La x FeO3 thin films and nanoparticles by incorporating the gradient and surface energy terms that are strongly dependent on the shape, size, and preparation method. A theoretical approach for describing the complex phase diagram of the multiferroic bismuth ferrite has been developed. Multiferroics are materials that exhibit multiple types of ferroic ordering, such as ferromagnetism and ferroelectricity, simultaneously. Bismuth ferrite is perhaps one of the best known of these as it exhibits multiferroicity at room temperature, making it useful for a range of applications, but the underlying physical mechanisms responsible for its multiferroic properties remains somewhat unclear. An international team of researchers led by Dmitry Karpinsky from the Scientific-Practical Materials Research Centre of NAS of Belarus and the Moscow Institute of Electronic Technology use existing experimental data to construct a Landau-Ginzbur-like Thermodynamic Potential that can not only provide a quantitatively description of bismuth ferrites known behavior, but also predicts new intermediate phases.
-
a Thermodynamic Potential and the temperature composition phase diagram for single crystalline k1 xnaxnbo3 0 x 0 5
Applied Physics Letters, 2017Co-Authors: Hannah Pohlmann, Jianjun Wang, Bo Wang, Long-qing ChenAbstract:Environment-friendly lead-free piezoelectric materials, such as the niobate perovskite compound (K1-xNaxNbO3), have attracted increasing attention over the last decade. Although extensive efforts have been made to study these materials experimentally, there have been much fewer theoretical studies on the microstructural evolution and property optimization of lead-free systems due to the lack of a comprehensive Thermodynamic assessment. In this study, we first established a general procedure for constructing Thermodynamic Potentials for ferroelectric systems. We then developed an eighth-order Landau Thermodynamic Potential for K1-xNaxNbO3 (0 ≤ x ≤ 0.5) single crystals, taking into account the low temperature quantum mechanical effects. Based on this Potential, we computed the spontaneous polarization and the dielectric constants for each composition as well as an overall temperature-composition phase diagram, all of which agree well with the available experimental data.
-
a Thermodynamic Potential and the temperature composition phase diagram for single crystalline k 1 x na x nbo 3 0 x 0 5
Applied Physics Letters, 2017Co-Authors: Hannah Pohlmann, Jianjun Wang, Bo Wang, Long-qing ChenAbstract:Environment-friendly lead-free piezoelectric materials, such as the niobate perovskite compound (K1-xNaxNbO3), have attracted increasing attention over the last decade. Although extensive efforts have been made to study these materials experimentally, there have been much fewer theoretical studies on the microstructural evolution and property optimization of lead-free systems due to the lack of a comprehensive Thermodynamic assessment. In this study, we first established a general procedure for constructing Thermodynamic Potentials for ferroelectric systems. We then developed an eighth-order Landau Thermodynamic Potential for K1-xNaxNbO3 (0 ≤ x ≤ 0.5) single crystals, taking into account the low temperature quantum mechanical effects. Based on this Potential, we computed the spontaneous polarization and the dielectric constants for each composition as well as an overall temperature-composition phase diagram, all of which agree well with the available experimental data.
-
a Thermodynamic Potential for ni45co5mn36 7in13 3 single crystal
Journal of Applied Physics, 2013Co-Authors: J J Wang, X Q, Houbing Huang, Z H Liu, Long-qing ChenAbstract:A Thermodynamic Potential as a function of the ferromagnetic, antiferromagnetic, and martensite order parameters is developed using existing experimental data. It successfully reproduces the single domain properties of Ni45Co5Mn36.7In13.3 bulk crystal, including the Curie temperature, the transition temperature from ferromagnetic austenite phase to antiferromagnetic martensite phase as well as its response to an externally applied magnetic field, the saturated magnetization, the martensite strain, the entropy change, and the magnetic permeability. It can be applied to explore the stress-strain and magnetic field-strain behaviors and implemented in phase field simulations to study the ferromagnetic, antiferromagnetic, and martensite domain stability and evolution.
Graham J. Nathan - One of the best experts on this subject based on the ideXlab platform.
-
Comparing the Thermodynamic Potential of alternative liquid metal oxides for the storage of solar thermal energy
Solar Energy, 2017Co-Authors: Mahyar Silakhori, Mehdi Jafarian, Maziar Arjomandi, Graham J. NathanAbstract:Abstract The relative Potential of liquid multivalent metal oxides for the storage of thermal energy as sensible, latent and/or thermochemical storage energy in a liquid chemical looping thermal enerrgy storage (LCL-TES) is reported. This LCL-TES cycle comprises a reduction reactor, an oxidation reactor, two reservoirs for storing the hot and cold medium and a heat recovery unit. The materials were assessed on the basis of their melting temperature, Gibbs free energy, reaction temperature and thermal storage capacity. Ellingham diagrams were used to identify regimes with a Potential for application in a LCL-TES, while phase diagrams were used to identify processes which combine sensible, latent and thermochemical heat storage. Based on these criteria, the oxide of CuO/Cu 2 O was found to have the greatest Thermodynamic Potential for use in a LCL-TES system with a total enthalpy of 404.67 kJ/mol for thermal storage. However, the high temperature of ∼1200 °C and corrosive nature of molten copper and its oxides will make this cycle challenging to implement. Lead, on the other hand has a lower total enthalpy of 250.09 kJ/mol, but is molten at lower temperatures.
-
Thermodynamic Potential of molten copper oxide for high temperature solar energy storage and oxygen production
Applied Energy, 2017Co-Authors: Mehdi Jafarian, Maziar Arjomandi, Graham J. NathanAbstract:Abstract A novel cycle, the chemical looping of molten copper oxide, is proposed with the Thermodynamic Potential to achieve sensible, latent and thermochemical heat storage with an energy density of approximately 5.0 GJ/m 3 , which is approximately 6 times more than the 0.83 GJ/m 3 of molten salt. This cycle avoids the technical challenges associated with the application of solid materials (especially multivalent metals) for thermochemical energy storage such as attrition, agglomeration, particle breakage and structural change in successive reduction and oxidation reactions, although it brings alternative challenges associated with the handling of molten metal oxides. A process path for the concept is proposed based on data from the literature for the equilibrium composition of copper and oxygen at different temperatures and gas phase pressures. The process has been modelled with codes developed in MATLAB. The calculations estimate that from the total input concentrated solar thermal energy into the system, about 73% can be absorbed, while the rest is lost through re-radiation heat loss. Furthermore, it is estimated that of the absorbed heat, approximately 95% is stored, while the rest leaves the system as high temperature gas. The calculations also predict that approximately 20% of the inlet solar thermal energy is partitioned as the chemical storage, which is also employed for oxygen production. Also reported is the sensitivity to the effects of key operating parameters.
-
Thermodynamic Potential of high temperature chemical looping combustion with molten iron oxide as the oxygen carrier
Chemical Engineering Research & Design, 2017Co-Authors: Mehdi Jafarian, Maziar Arjomandi, Graham J. NathanAbstract:Abstract The Thermodynamic Potential of a chemical looping combustion (CLC) system using molten iron slag as the oxygen carrier (OC) for the combustion of methane is reported. A configuration of two inter-connected bubbling column reactors is proposed as a plausible configuration for the air and fuel reactors to facilitate the heating of a pressurised hot gas stream to an estimated temperature of 1350 °C. This approach has Potential to avoid the technical challenges associated with the use of the solid OC employed in conventional CLC systems such as particle breakage, attrition, agglomeration and structural change that arise from successive reduction and oxidation (Red-Ox) cycles. However, it brings alternative challenges associated with the handling of molten metal oxides such as proper material selection and solidification of the LOC, which will require further work to full identify and resolve. The process has been modelled using codes developed with MATLAB and HSC Chemistry 7.0 software and compared with published data. The model was used to estimate that a fuel conversion efficiency of more than 97% can be achieved with molten iron oxide as the oxygen carrier, together with a mole fraction of the iron and iron oxides in the product gas of less than 10−6. A sensitivity to molar ratios of liquid oxygen carrier, steam to fuel flow rate and the operating pressure is also reported.
Maziar Arjomandi - One of the best experts on this subject based on the ideXlab platform.
-
Thermodynamic Potential of a high concentration hybrid photovoltaic thermal plant for co production of steam and electricity
Journal of Thermal Analysis and Calorimetry, 2021Co-Authors: Marjan Goodarzi, M M Sarafraz, Iskander Tlili, Tawfeeq Abdullah Alkanhal, Maziar ArjomandiAbstract:A Thermodynamic model was developed to assess the energetic performance of a dual receiver concentrated photovoltaic/thermal plant for the co-production of steam, electricity and hot water/air. The system utilizes a dual receiver including a steam generator based on a solar receiver and a concentrated PV/thermal receiver. The system is regulated so that a fraction (φ) of the thermal energy absorbed by the solar field is partitioned for the steam generator, while the rest is dedicated to the CPV/T unit. The results showed that the thermal performance of the system strongly depends on the φ value such that the system can simultaneously produce electricity and steam, while warm air and water can also be produced by cooling the CPV/T unit. Also, the thermal performance of the coolant is a key element to the system, which highlights the Potential of nano-suspensions as a coolant in the system. Likewise, the assessment of the process plant was performed at field area of 2500–10,000 m2, the solar concentration ratio of 50–200 and the CPV/T coolant’s outlet temperature of 323–353 K. It was found that the highest values of thermal losses can be ~ 2% of the total thermal input of the plant. Also, a trade-off trend was identified between the φ value, steam and electricity production. It was also found that at a solar concentration ratio of 2000, the system is competitive to produce steam to be fed into a multi-flash desalination system. The energetic performance of the system revealed that at φ = 0.75, about 48% of the energy is partitioned for the hot water and hot air production for the agricultural application, while 24% is used for the electricity and 26% is used for the steam production.
-
Comparing the Thermodynamic Potential of alternative liquid metal oxides for the storage of solar thermal energy
Solar Energy, 2017Co-Authors: Mahyar Silakhori, Mehdi Jafarian, Maziar Arjomandi, Graham J. NathanAbstract:Abstract The relative Potential of liquid multivalent metal oxides for the storage of thermal energy as sensible, latent and/or thermochemical storage energy in a liquid chemical looping thermal enerrgy storage (LCL-TES) is reported. This LCL-TES cycle comprises a reduction reactor, an oxidation reactor, two reservoirs for storing the hot and cold medium and a heat recovery unit. The materials were assessed on the basis of their melting temperature, Gibbs free energy, reaction temperature and thermal storage capacity. Ellingham diagrams were used to identify regimes with a Potential for application in a LCL-TES, while phase diagrams were used to identify processes which combine sensible, latent and thermochemical heat storage. Based on these criteria, the oxide of CuO/Cu 2 O was found to have the greatest Thermodynamic Potential for use in a LCL-TES system with a total enthalpy of 404.67 kJ/mol for thermal storage. However, the high temperature of ∼1200 °C and corrosive nature of molten copper and its oxides will make this cycle challenging to implement. Lead, on the other hand has a lower total enthalpy of 250.09 kJ/mol, but is molten at lower temperatures.
-
Thermodynamic Potential of molten copper oxide for high temperature solar energy storage and oxygen production
Applied Energy, 2017Co-Authors: Mehdi Jafarian, Maziar Arjomandi, Graham J. NathanAbstract:Abstract A novel cycle, the chemical looping of molten copper oxide, is proposed with the Thermodynamic Potential to achieve sensible, latent and thermochemical heat storage with an energy density of approximately 5.0 GJ/m 3 , which is approximately 6 times more than the 0.83 GJ/m 3 of molten salt. This cycle avoids the technical challenges associated with the application of solid materials (especially multivalent metals) for thermochemical energy storage such as attrition, agglomeration, particle breakage and structural change in successive reduction and oxidation reactions, although it brings alternative challenges associated with the handling of molten metal oxides. A process path for the concept is proposed based on data from the literature for the equilibrium composition of copper and oxygen at different temperatures and gas phase pressures. The process has been modelled with codes developed in MATLAB. The calculations estimate that from the total input concentrated solar thermal energy into the system, about 73% can be absorbed, while the rest is lost through re-radiation heat loss. Furthermore, it is estimated that of the absorbed heat, approximately 95% is stored, while the rest leaves the system as high temperature gas. The calculations also predict that approximately 20% of the inlet solar thermal energy is partitioned as the chemical storage, which is also employed for oxygen production. Also reported is the sensitivity to the effects of key operating parameters.
-
Thermodynamic Potential of high temperature chemical looping combustion with molten iron oxide as the oxygen carrier
Chemical Engineering Research & Design, 2017Co-Authors: Mehdi Jafarian, Maziar Arjomandi, Graham J. NathanAbstract:Abstract The Thermodynamic Potential of a chemical looping combustion (CLC) system using molten iron slag as the oxygen carrier (OC) for the combustion of methane is reported. A configuration of two inter-connected bubbling column reactors is proposed as a plausible configuration for the air and fuel reactors to facilitate the heating of a pressurised hot gas stream to an estimated temperature of 1350 °C. This approach has Potential to avoid the technical challenges associated with the use of the solid OC employed in conventional CLC systems such as particle breakage, attrition, agglomeration and structural change that arise from successive reduction and oxidation (Red-Ox) cycles. However, it brings alternative challenges associated with the handling of molten metal oxides such as proper material selection and solidification of the LOC, which will require further work to full identify and resolve. The process has been modelled using codes developed with MATLAB and HSC Chemistry 7.0 software and compared with published data. The model was used to estimate that a fuel conversion efficiency of more than 97% can be achieved with molten iron oxide as the oxygen carrier, together with a mole fraction of the iron and iron oxides in the product gas of less than 10−6. A sensitivity to molar ratios of liquid oxygen carrier, steam to fuel flow rate and the operating pressure is also reported.
M M Sarafraz - One of the best experts on this subject based on the ideXlab platform.
-
Thermodynamic Potential of a high concentration hybrid photovoltaic thermal plant for co production of steam and electricity
Journal of Thermal Analysis and Calorimetry, 2021Co-Authors: Marjan Goodarzi, M M Sarafraz, Iskander Tlili, Tawfeeq Abdullah Alkanhal, Maziar ArjomandiAbstract:A Thermodynamic model was developed to assess the energetic performance of a dual receiver concentrated photovoltaic/thermal plant for the co-production of steam, electricity and hot water/air. The system utilizes a dual receiver including a steam generator based on a solar receiver and a concentrated PV/thermal receiver. The system is regulated so that a fraction (φ) of the thermal energy absorbed by the solar field is partitioned for the steam generator, while the rest is dedicated to the CPV/T unit. The results showed that the thermal performance of the system strongly depends on the φ value such that the system can simultaneously produce electricity and steam, while warm air and water can also be produced by cooling the CPV/T unit. Also, the thermal performance of the coolant is a key element to the system, which highlights the Potential of nano-suspensions as a coolant in the system. Likewise, the assessment of the process plant was performed at field area of 2500–10,000 m2, the solar concentration ratio of 50–200 and the CPV/T coolant’s outlet temperature of 323–353 K. It was found that the highest values of thermal losses can be ~ 2% of the total thermal input of the plant. Also, a trade-off trend was identified between the φ value, steam and electricity production. It was also found that at a solar concentration ratio of 2000, the system is competitive to produce steam to be fed into a multi-flash desalination system. The energetic performance of the system revealed that at φ = 0.75, about 48% of the energy is partitioned for the hot water and hot air production for the agricultural application, while 24% is used for the electricity and 26% is used for the steam production.
-
Thermodynamic Potential of a novel plasma assisted sustainable process for co production of ammonia and hydrogen with liquid metals
Energy Conversion and Management, 2020Co-Authors: M M Sarafraz, Nam Nghiep Tran, N Pourali, Evgeny V Rebrov, Volker HesselAbstract:Abstract In the present article, the Thermodynamic Potential of a sustainable plasma-assisted nitrogen fixation process for co-production of ammonia and hydrogen is investigated. The developed process takes advantage of chemical looping system by using a liquid metal such as gallium to drive nitrogen fixation reaction using three reactors including reactor R1 to produce gallium nitride from gallium and nitrogen, reactor R2 to produce ammonia and hydrogen from gallium nitride, and plasma reactor R3 to convert gallium oxide to pure gallium. The results of the Thermodynamic assessments showed that the proposed reactions are spontaneous and feasible to occur in the reactors. Likewise, the first two reactions are exothermic with Δ H = - 230 k J m o l and Δ H = - 239 k J m o l in the reactors R1 and R2, respectively with an equilibrium chemical conversion of 100%. The plasma reactor requires thermal energy to drive an endothermic reaction of gallium oxide dissociation with Δ H = + 870 k J m o l . Thermochemical equilibrium analysis showed that the molar ratio of steam to GaN, as well as the operating pressure and temperature of reactor R2 are the main operating parameters identifying the product composition in the reactor such that by increasing the temperature, the molar ratio of hydrogen to ammonia increases. However, by increasing the molar ratio of steam/GaN (φ value) from 0.1 to 1, the hydrogen content of the reactor increases from 45% to 70% at 400 °C. For φ > 1.0, the hydrogen content decreases while more hydrogen participate in the formation of NH3 thereby increasing the mole fraction of ammonia in the reactor. The equilibrium chemical conversion of all three reactors is expected to reach the completion point (χ = 100%) due to the highly negative Gibbs free energy of the liquid metal-based reactions together with a large thermal driving force supported by thermal plasma reactor. Finally, a scalability study points at a possible use of the new disruptive process design at small scale, and possible industrial transformation scenarios for a distributed production at a local site of consumption are depicted.
Hannah Pohlmann - One of the best experts on this subject based on the ideXlab platform.
-
a Thermodynamic Potential and the temperature composition phase diagram for single crystalline k1 xnaxnbo3 0 x 0 5
Applied Physics Letters, 2017Co-Authors: Hannah Pohlmann, Jianjun Wang, Bo Wang, Long-qing ChenAbstract:Environment-friendly lead-free piezoelectric materials, such as the niobate perovskite compound (K1-xNaxNbO3), have attracted increasing attention over the last decade. Although extensive efforts have been made to study these materials experimentally, there have been much fewer theoretical studies on the microstructural evolution and property optimization of lead-free systems due to the lack of a comprehensive Thermodynamic assessment. In this study, we first established a general procedure for constructing Thermodynamic Potentials for ferroelectric systems. We then developed an eighth-order Landau Thermodynamic Potential for K1-xNaxNbO3 (0 ≤ x ≤ 0.5) single crystals, taking into account the low temperature quantum mechanical effects. Based on this Potential, we computed the spontaneous polarization and the dielectric constants for each composition as well as an overall temperature-composition phase diagram, all of which agree well with the available experimental data.
-
a Thermodynamic Potential and the temperature composition phase diagram for single crystalline k 1 x na x nbo 3 0 x 0 5
Applied Physics Letters, 2017Co-Authors: Hannah Pohlmann, Jianjun Wang, Bo Wang, Long-qing ChenAbstract:Environment-friendly lead-free piezoelectric materials, such as the niobate perovskite compound (K1-xNaxNbO3), have attracted increasing attention over the last decade. Although extensive efforts have been made to study these materials experimentally, there have been much fewer theoretical studies on the microstructural evolution and property optimization of lead-free systems due to the lack of a comprehensive Thermodynamic assessment. In this study, we first established a general procedure for constructing Thermodynamic Potentials for ferroelectric systems. We then developed an eighth-order Landau Thermodynamic Potential for K1-xNaxNbO3 (0 ≤ x ≤ 0.5) single crystals, taking into account the low temperature quantum mechanical effects. Based on this Potential, we computed the spontaneous polarization and the dielectric constants for each composition as well as an overall temperature-composition phase diagram, all of which agree well with the available experimental data.
