The second law of thermodynamics has been proven by many facts in classical world. Is there any new property of it in quantum world？ In this paper, we calculate the change of entropy in T.D. Kieu＇s model for quantum...The second law of thermodynamics has been proven by many facts in classical world. Is there any new property of it in quantum world？ In this paper, we calculate the change of entropy in T.D. Kieu＇s model for quantum heat engine （QHE） and prove the broad validity of the second law of thermodynamics. It is shown that the entropy of the quantum heat engine neither decreases in a whole cycle, nor decreases in either stage of the cycle. The second law of thermodynamics still holds in this QHE model. Moreover, although the modified quantum heat engine is capable of extracting more work, its efficiency does not improve at all. It is neither beyond the efficiency of T.D. Kieu＇s initial model,nor greater than the reversible Carnot efficiency.展开更多
The aim of this numerical investigation is to evaluate the laminar forced convection of biologically synthesized water-silver nanofluid through a heat sink(HS)filled with porous foam(PHS)using first and second laws of...The aim of this numerical investigation is to evaluate the laminar forced convection of biologically synthesized water-silver nanofluid through a heat sink(HS)filled with porous foam(PHS)using first and second laws of thermodynamics.The impacts of inlet velocity(V=0.5–3 m·s^-1)and volume fraction of nanofluid(φ=0–1%)on the performance metrics of HS are assessed and the outcomes are compared with those of the non-porous HS(NHS).The outcomes revealed that for both the PHS and NHS,the increase of V causes an intensification in convection coefficient,pumping power,and entropy generation due to fluid friction,while the maximum CPU temperature,thermal resistance,and entropy generation due to the heat transfer reduces by boosting V.Also,it was found that the augmentation of V results in intensification in convection coefficient,pumping power,overall hydrothermal performance,and frictional entropy generation,while the opposite is true for maximum CPU temperature,thermal resistance,and thermal entropy generation.Furthermore,it was reported that,except forφ=0.5%,the overall hydrothermal performance of NHS is better than that of PHS,while PHS has better second-law performance than NHS in all the studied cases.Also,it can be concluded that the best hydrothermal performance for PHS belongs toφ=1%and V=0.5 m·s^-1,while for NHS,these values are 1%and 2 m·s^-1.展开更多
The purpose of this paper is to introduce to you, the Western people, nowadays a “widely unknown” Japanese thermodynamicist by the name of Motoyosi Sugita and his study on the thermodynamics of transient phenomena a...The purpose of this paper is to introduce to you, the Western people, nowadays a “widely unknown” Japanese thermodynamicist by the name of Motoyosi Sugita and his study on the thermodynamics of transient phenomena and his theory of life. This is because although he was one of the top theoretical physicists in Japan before, during and after WWII and after WWII he promoted the establishment of the biophysical society of Japan as one of the founding members, he himself and his studies themselves have seemed to be totally forgotten nowadays in spite that his study was absolutely important for the study of life. Therefore, in this paper I would like to present what kind of person he was and what he studied in physics as a review on the physics work of Motoyosi Sugita for the first time. I will follow his past studies to introduce his ideas in theoretical physics as well as in biophysics as follows: He proposed the bright ideas such as the quasi-static change in the broad sense, the virtual heat, and the field of chemical potential etc. in order to establish his own theory of thermodynamics of transient phenomena, as the generalization of the Onsager-Prigogine’s theory of the irreversible processes. By the concept of the field of chemical potential that acquired the nonlinear transport, he was seemingly successful to exceed and go beyond the scope of Onsager and Prigogine. Once he established his thermodynamics, he explored the existence of the 4th law of thermodynamics for the foundation of theory of life. He applied it to broad categories of transient phenomena including life and life being such as the theory of metabolism. He regarded the 4th law of thermodynamics as the maximum principle in transient phenomena. He tried to prove it all life long. Since I have recently found that his maximum principle can be included in more general maximum principle, which was known as the Pontryagin’s maximum principle in the theory of optimal control, I would like to explain such theories produced by Motoyosi Sugita as detailed as possible. And also I have put short history of Motoyosi Sugita’s personal life in order for you to know him well. I hope that this article helps you to know this wonderful man and understand what he did in the past, which was totally forgotten in the world and even in Japan.展开更多
This paper introduces an energy-analysis of the flow of electrical charges and magnetic flux in addition to the flow of heat into a thermodynamic system. The analysis depends on the results of a held experiment on a m...This paper introduces an energy-analysis of the flow of electrical charges and magnetic flux in addition to the flow of heat into a thermodynamic system. The analysis depends on the results of a held experiment on a magnet that attracted iron balls and a Faraday’s discovery as well as similarities between the laws characterizing the flow of electric charges, magnetic flux and heat. As the electric charge and magnetic flux produce entropy changes in some applications as magnetic hysteresis and capacitive deionization, we may express the electric charges and magnetic flux in terms of entropy changes times their corresponding potentials by analogy to expressing heat as a product of temperature and entropy changes. Introducing such postulates into the held energy-analysis;a new fundamental equation of thermodynamics that embraces the flow of electric charges and magnetic flux in terms of the electric and magnetic potentials was derived. The derived equation proved its truth in numerous studies of general energy interactions. Such postulates help also in defining the electric charge and magnetic flux as categories of electromagnetic waves of assigned electric or magnetic potentials and offer plausible explanations of newly discovered phenomena in the fields of electromagnetism and thermodynamics as Kerr effect and magnetic expansion.展开更多
The present paper describes the energy analysis of a regenerative vapour power system. The regenerative steam turbines based on the Rankine cycle and comprised of vapour extractions have been used industrially since t...The present paper describes the energy analysis of a regenerative vapour power system. The regenerative steam turbines based on the Rankine cycle and comprised of vapour extractions have been used industrially since the beginning of the 20th century, particularly regarding the processes of electrical production. After having performed worked in the first stages of the turbine, part of the vapour is directed toward a regenerative exchanger and heats feedwater coming from the condenser. This process is known as regeneration, and the heat exchanger where the heat is transferred from steam is called a regenerator (or a feedwater heater). The profit in the output brought by regenerative rakings is primarily enabled by the lack of exchange of the tapped vapour reheating water with the low-temperature reservoir. The economic optimum is often fixed at seven extractions. One knows the Carnot relation, which is the best possible theoretical yield of a dual-temperature cycle;in a Carnot cycle, one makes the assumption that both compressions and expansions are isentropic. This article studies an ideal theoretical machine comprised of vapour extractions in which each cycle partial of tapped vapour obeys these same compressions and isentropic expansions.展开更多
On the basis of non-equilibrium thermodynamic theory,the coupling phenomena of heat and mass transfer during the process of moisture exchange across a membrane were studied and the relevant physical and mathematical m...On the basis of non-equilibrium thermodynamic theory,the coupling phenomena of heat and mass transfer during the process of moisture exchange across a membrane were studied and the relevant physical and mathematical models were established.Formulae for calculating the four characteristic parameters included in the non-equilibrium thermodynamic model were derived,and the dependences of these parameters on the temperatures and concentrations on the two sides of the membrane were analyzed,providing a basis for calculating the heat and mass fluxes.The effects of temperature and concentration differences between the two sides of membrane and the membrane average temperature on the transmembrane mass and heat fluxes were investigated.The results show that for a given membrane average temperature,a larger concentration difference or a smaller temperature difference leads to a higher mass flux.For fixed concentration and temperature differences and with the mass flux predominantly caused by the concentration difference,a higher membrane average temperature yields a higher mass flux.The ratio of the heat of sorption induced by mass flow to total heat relates not only to the temperature and concentration differences between the two sides of membrane but also to the membrane average temperature and the ratio increases when the temperature difference is reduced.展开更多
In the present work it is shown that the single phase lagging heat conduction not only avoids the infinite heat propagation speed assumed by the conventional Fourier law, but also complies with Galilean principle of r...In the present work it is shown that the single phase lagging heat conduction not only avoids the infinite heat propagation speed assumed by the conventional Fourier law, but also complies with Galilean principle of relativity. Therefore it is more advantageous than the Cattaneo-Vernotte model. Based on the single-phase-lagging heat conduction model, the condition for the occurrence of thermal vibration of heat conduction is established. In order to resolve the contradiction that the thermal vibration violates the second law of thermodynamics, the extended irreversible thermodynamics is improved and a generalized entropy definition is introduced. In the framework of the newly-developed extended irreversible thermodynamics the thermal vibration phenomena are consistent with the second law of thermodynamics.展开更多
基金The project supported by National Natural Science Foundation of China under Grant No. 10404039
文摘The second law of thermodynamics has been proven by many facts in classical world. Is there any new property of it in quantum world？ In this paper, we calculate the change of entropy in T.D. Kieu＇s model for quantum heat engine （QHE） and prove the broad validity of the second law of thermodynamics. It is shown that the entropy of the quantum heat engine neither decreases in a whole cycle, nor decreases in either stage of the cycle. The second law of thermodynamics still holds in this QHE model. Moreover, although the modified quantum heat engine is capable of extracting more work, its efficiency does not improve at all. It is neither beyond the efficiency of T.D. Kieu＇s initial model,nor greater than the reversible Carnot efficiency.
文摘The aim of this numerical investigation is to evaluate the laminar forced convection of biologically synthesized water-silver nanofluid through a heat sink(HS)filled with porous foam(PHS)using first and second laws of thermodynamics.The impacts of inlet velocity(V=0.5–3 m·s^-1)and volume fraction of nanofluid(φ=0–1%)on the performance metrics of HS are assessed and the outcomes are compared with those of the non-porous HS(NHS).The outcomes revealed that for both the PHS and NHS,the increase of V causes an intensification in convection coefficient,pumping power,and entropy generation due to fluid friction,while the maximum CPU temperature,thermal resistance,and entropy generation due to the heat transfer reduces by boosting V.Also,it was found that the augmentation of V results in intensification in convection coefficient,pumping power,overall hydrothermal performance,and frictional entropy generation,while the opposite is true for maximum CPU temperature,thermal resistance,and thermal entropy generation.Furthermore,it was reported that,except forφ=0.5%,the overall hydrothermal performance of NHS is better than that of PHS,while PHS has better second-law performance than NHS in all the studied cases.Also,it can be concluded that the best hydrothermal performance for PHS belongs toφ=1%and V=0.5 m·s^-1,while for NHS,these values are 1%and 2 m·s^-1.
文摘The purpose of this paper is to introduce to you, the Western people, nowadays a “widely unknown” Japanese thermodynamicist by the name of Motoyosi Sugita and his study on the thermodynamics of transient phenomena and his theory of life. This is because although he was one of the top theoretical physicists in Japan before, during and after WWII and after WWII he promoted the establishment of the biophysical society of Japan as one of the founding members, he himself and his studies themselves have seemed to be totally forgotten nowadays in spite that his study was absolutely important for the study of life. Therefore, in this paper I would like to present what kind of person he was and what he studied in physics as a review on the physics work of Motoyosi Sugita for the first time. I will follow his past studies to introduce his ideas in theoretical physics as well as in biophysics as follows: He proposed the bright ideas such as the quasi-static change in the broad sense, the virtual heat, and the field of chemical potential etc. in order to establish his own theory of thermodynamics of transient phenomena, as the generalization of the Onsager-Prigogine’s theory of the irreversible processes. By the concept of the field of chemical potential that acquired the nonlinear transport, he was seemingly successful to exceed and go beyond the scope of Onsager and Prigogine. Once he established his thermodynamics, he explored the existence of the 4th law of thermodynamics for the foundation of theory of life. He applied it to broad categories of transient phenomena including life and life being such as the theory of metabolism. He regarded the 4th law of thermodynamics as the maximum principle in transient phenomena. He tried to prove it all life long. Since I have recently found that his maximum principle can be included in more general maximum principle, which was known as the Pontryagin’s maximum principle in the theory of optimal control, I would like to explain such theories produced by Motoyosi Sugita as detailed as possible. And also I have put short history of Motoyosi Sugita’s personal life in order for you to know him well. I hope that this article helps you to know this wonderful man and understand what he did in the past, which was totally forgotten in the world and even in Japan.
文摘This paper introduces an energy-analysis of the flow of electrical charges and magnetic flux in addition to the flow of heat into a thermodynamic system. The analysis depends on the results of a held experiment on a magnet that attracted iron balls and a Faraday’s discovery as well as similarities between the laws characterizing the flow of electric charges, magnetic flux and heat. As the electric charge and magnetic flux produce entropy changes in some applications as magnetic hysteresis and capacitive deionization, we may express the electric charges and magnetic flux in terms of entropy changes times their corresponding potentials by analogy to expressing heat as a product of temperature and entropy changes. Introducing such postulates into the held energy-analysis;a new fundamental equation of thermodynamics that embraces the flow of electric charges and magnetic flux in terms of the electric and magnetic potentials was derived. The derived equation proved its truth in numerous studies of general energy interactions. Such postulates help also in defining the electric charge and magnetic flux as categories of electromagnetic waves of assigned electric or magnetic potentials and offer plausible explanations of newly discovered phenomena in the fields of electromagnetism and thermodynamics as Kerr effect and magnetic expansion.
文摘The present paper describes the energy analysis of a regenerative vapour power system. The regenerative steam turbines based on the Rankine cycle and comprised of vapour extractions have been used industrially since the beginning of the 20th century, particularly regarding the processes of electrical production. After having performed worked in the first stages of the turbine, part of the vapour is directed toward a regenerative exchanger and heats feedwater coming from the condenser. This process is known as regeneration, and the heat exchanger where the heat is transferred from steam is called a regenerator (or a feedwater heater). The profit in the output brought by regenerative rakings is primarily enabled by the lack of exchange of the tapped vapour reheating water with the low-temperature reservoir. The economic optimum is often fixed at seven extractions. One knows the Carnot relation, which is the best possible theoretical yield of a dual-temperature cycle;in a Carnot cycle, one makes the assumption that both compressions and expansions are isentropic. This article studies an ideal theoretical machine comprised of vapour extractions in which each cycle partial of tapped vapour obeys these same compressions and isentropic expansions.
基金supported by the National Natural Science Foundation of China (50576040)
文摘On the basis of non-equilibrium thermodynamic theory,the coupling phenomena of heat and mass transfer during the process of moisture exchange across a membrane were studied and the relevant physical and mathematical models were established.Formulae for calculating the four characteristic parameters included in the non-equilibrium thermodynamic model were derived,and the dependences of these parameters on the temperatures and concentrations on the two sides of the membrane were analyzed,providing a basis for calculating the heat and mass fluxes.The effects of temperature and concentration differences between the two sides of membrane and the membrane average temperature on the transmembrane mass and heat fluxes were investigated.The results show that for a given membrane average temperature,a larger concentration difference or a smaller temperature difference leads to a higher mass flux.For fixed concentration and temperature differences and with the mass flux predominantly caused by the concentration difference,a higher membrane average temperature yields a higher mass flux.The ratio of the heat of sorption induced by mass flow to total heat relates not only to the temperature and concentration differences between the two sides of membrane but also to the membrane average temperature and the ratio increases when the temperature difference is reduced.
基金the National Basic Research Program of China (Grant No. 2007CB206900)
文摘In the present work it is shown that the single phase lagging heat conduction not only avoids the infinite heat propagation speed assumed by the conventional Fourier law, but also complies with Galilean principle of relativity. Therefore it is more advantageous than the Cattaneo-Vernotte model. Based on the single-phase-lagging heat conduction model, the condition for the occurrence of thermal vibration of heat conduction is established. In order to resolve the contradiction that the thermal vibration violates the second law of thermodynamics, the extended irreversible thermodynamics is improved and a generalized entropy definition is introduced. In the framework of the newly-developed extended irreversible thermodynamics the thermal vibration phenomena are consistent with the second law of thermodynamics.
