A modified power-law fluid of second grade is considered. The model is a combination of power-law and second grade fluid in which the fluid may exhibit normal stresses, shear thinning or shear thickening behaviors. Th...A modified power-law fluid of second grade is considered. The model is a combination of power-law and second grade fluid in which the fluid may exhibit normal stresses, shear thinning or shear thickening behaviors. The equations of motion are derived for two dimensional incompressible flows, and from which the boundary layer equations are derived. Symmetries of the boundary layer equations are found by using Lie group theory, and then group classification with respect to power-law index is performed. By using one of the symmetries, namely the scaling symmetry, the partial differential system is transformed into an ordinary differential system, which is numerically integrated under the classical boundary layer conditions. Effects of power-law index and second grade coefficient on the boundary layers are shown and solutions are contrasted with the usual second grade fluid solutions.展开更多
There have emerged ample literature about the Second Law analysis of extraterrestrial and terrestrial solar radiation consequent to the pioneer works by R. Petela and D. C. Spanner, of which most are irrelevant to the...There have emerged ample literature about the Second Law analysis of extraterrestrial and terrestrial solar radiation consequent to the pioneer works by R. Petela and D. C. Spanner, of which most are irrelevant to the frequency distribution of solar radiation. Since the Second Law analysis was introduced to the fields like photovoltaic and photosynthesis, rendering a need for a method closely related to solar radiation spectrum, some authors created wavelength dependent dilute factots to take the various influence of atmosphere on the frequency distribution into consideration. Because of the complexity of the influence on different frequency, it is not convenient and accurate enough to practically apply the present exergy theories of diluted solar radiation to real solar exergy systems at the surface of the earth. This paper shows a numerical method of Second Law analysis in dealing with the cases of diluted solar irradiance on the earth, based on the observed spectra of global direct and diffuse展开更多
According to the existing concrete core samples obtained in site, chloride concentration and porosity of existing normal hydraulic concrete were measured, and chloride diffusivity in existing hydraulic concrete was st...According to the existing concrete core samples obtained in site, chloride concentration and porosity of existing normal hydraulic concrete were measured, and chloride diffusivity in existing hydraulic concrete was studied. By Fick’s second law, the chloride diffusion coefficients in the steady diffusion area were calculated. The chloride diffusion of different mix proportion concrete was tested, and chloride diffusion coefficients and porosities of freshly concrete were measured, moreover, the relationship between diffusion coefficient and porosity was analyzed. The results show that the varying law of chloride diffusion coefficient with exposure time of existing concrete can be predicted in a better way by Fick’s second law and water-cement ratios or porosity of concrete and chloride concentration in existing concrete.展开更多
The semi-classical black hole tunneling radiation (Parikh-Wilczek tunneling proposal) is calculated undera minimal length uncertainty analysis.It is shown that,the generalized second law of thermodynamics may bound th...The semi-classical black hole tunneling radiation (Parikh-Wilczek tunneling proposal) is calculated undera minimal length uncertainty analysis.It is shown that,the generalized second law of thermodynamics may bound thetunneling probability radiation of a Reissner-Nordstrom black hole radiation.展开更多
Loschmidt’s paradox is extended by replacing its assumption of time reversibility with full CPT symmetry. Mobility is identified as a means for expressing collisions or dissipation, and the cross product of its gradi...Loschmidt’s paradox is extended by replacing its assumption of time reversibility with full CPT symmetry. Mobility is identified as a means for expressing collisions or dissipation, and the cross product of its gradient with the magnetic field, for expressing parity. Three phenomena incorporating such cross products are identified. The first is the cross product of the mobility gradient with the magnetic field. The second combines this cross product with the E cross B drift. The third is the reciprocal of the Nernst effect expressed as a cross product of the temperature gradient and the magnetic field. Simulations are conducted for testing Loschmidt’s extended paradox. Onsager’s exclusion of magnetic fields and rotation from reciprocals violates CPT symmetry and is unjustified. All three cross-product phenomena skew statistics in a fashion unanticipated by Boltzmann’s assumptions in his H-Theorem. CPT symmetric systems fall outside the assumptions of the theorem which is not rendered invalid but simply limited to its domain of applicability. Therefore, these systems do not violate the second law as Boltzmann defines it. They bypass it.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
A Faraday isolator is shown to develop a temperature difference between its input and output, but still complies with the second law when all the heat carriers, in this case, photons are homogeneous and indistinguisha...A Faraday isolator is shown to develop a temperature difference between its input and output, but still complies with the second law when all the heat carriers, in this case, photons are homogeneous and indistinguishable. This result is a consequence of the H-theorem which assumes homogeneity and indistinguishability of particles. However, when a thermal feedback path is added, in which heat carriers have physical properties different from the photons in the isolator, then a heterogeneous system is formed not covered by the H-theorem, and the second law is violated.展开更多
A Faraday isolator is shown to develop a temperature difference between its input and output, but still complies with the second law when all the heat carriers, in this case, photons are homogeneous and indistinguisha...A Faraday isolator is shown to develop a temperature difference between its input and output, but still complies with the second law when all the heat carriers, in this case, photons are homogeneous and indistinguishable. This result is a consequence of the H-theorem which assumes homogeneity and indistinguishability of particles. However, when a thermal feedback path is added, in which heat carriers have physical properties different from the photons in the isolator, then a heterogeneous system is formed not covered by the H-theorem, and the second law is violated.展开更多
We propose a reformulation of Newton’s second law of motion for charged particles and possible applications of the reformulation to quantum dynamics. We show that the negative energy states arising from the Dirac equ...We propose a reformulation of Newton’s second law of motion for charged particles and possible applications of the reformulation to quantum dynamics. We show that the negative energy states arising from the Dirac equation in relativistic quantum mechanics can be verified using the reformulating framework. We also discuss possible hidden dynamics underlying the concept of quantum jumps in quantum mechanics as outlined in Schr<span style="font-size:12px;white-space:nowrap;">ö</span>dinger’s article: ARE THERE QUANTUM JUMPS? In this case, we show that the hidden dynamics of quantum jumps are also determined by the Coulomb interaction between charged particles.展开更多
Refrigeration coefficient,ε,is usually calculated by using the First Law of Thermodynamics.In this paper,a new derivation process is introduced through the combination of the Second Law of Thermodynamics with the Fir...Refrigeration coefficient,ε,is usually calculated by using the First Law of Thermodynamics.In this paper,a new derivation process is introduced through the combination of the Second Law of Thermodynamics with the First Law of Thermodynamics.As a result,two new calculation equations for refrigeration coefficient are proposed.One equation is equivalent to the common method,but its form is a little complicated for real calculation.Another equation is the further simplification,and can be used to calculate the refrigeration coefficient instead of common method with a permit error.展开更多
Based on the entropy generation concept of thermodynamics, this paper established a general theoretical model for the analysis of entropy generation to optimize fins, in which the minimum entropy generation was select...Based on the entropy generation concept of thermodynamics, this paper established a general theoretical model for the analysis of entropy generation to optimize fins, in which the minimum entropy generation was selected as the object to be studied. The irreversibility due to heat transfer and friction was taken into account so that the minimum entropy generation number has been analyzed with respect to second law of thermodynamics in the forced cross-flow. The optimum dimensions of cylinder pins were discussed. It’s found that the minimum entropy generation number depends on parameters related to the fluid and fin physical parameters. Variations of the minimum entropy generation number with different parameters were analyzed.展开更多
文摘A modified power-law fluid of second grade is considered. The model is a combination of power-law and second grade fluid in which the fluid may exhibit normal stresses, shear thinning or shear thickening behaviors. The equations of motion are derived for two dimensional incompressible flows, and from which the boundary layer equations are derived. Symmetries of the boundary layer equations are found by using Lie group theory, and then group classification with respect to power-law index is performed. By using one of the symmetries, namely the scaling symmetry, the partial differential system is transformed into an ordinary differential system, which is numerically integrated under the classical boundary layer conditions. Effects of power-law index and second grade coefficient on the boundary layers are shown and solutions are contrasted with the usual second grade fluid solutions.
文摘There have emerged ample literature about the Second Law analysis of extraterrestrial and terrestrial solar radiation consequent to the pioneer works by R. Petela and D. C. Spanner, of which most are irrelevant to the frequency distribution of solar radiation. Since the Second Law analysis was introduced to the fields like photovoltaic and photosynthesis, rendering a need for a method closely related to solar radiation spectrum, some authors created wavelength dependent dilute factots to take the various influence of atmosphere on the frequency distribution into consideration. Because of the complexity of the influence on different frequency, it is not convenient and accurate enough to practically apply the present exergy theories of diluted solar radiation to real solar exergy systems at the surface of the earth. This paper shows a numerical method of Second Law analysis in dealing with the cases of diluted solar irradiance on the earth, based on the observed spectra of global direct and diffuse
基金Funded by the National Natural Science Foundation of China (No.50879079)Science and Technology Plan Project of Zhejiang Province (No.2007C23058)
文摘According to the existing concrete core samples obtained in site, chloride concentration and porosity of existing normal hydraulic concrete were measured, and chloride diffusivity in existing hydraulic concrete was studied. By Fick’s second law, the chloride diffusion coefficients in the steady diffusion area were calculated. The chloride diffusion of different mix proportion concrete was tested, and chloride diffusion coefficients and porosities of freshly concrete were measured, moreover, the relationship between diffusion coefficient and porosity was analyzed. The results show that the varying law of chloride diffusion coefficient with exposure time of existing concrete can be predicted in a better way by Fick’s second law and water-cement ratios or porosity of concrete and chloride concentration in existing concrete.
文摘The semi-classical black hole tunneling radiation (Parikh-Wilczek tunneling proposal) is calculated undera minimal length uncertainty analysis.It is shown that,the generalized second law of thermodynamics may bound thetunneling probability radiation of a Reissner-Nordstrom black hole radiation.
文摘Loschmidt’s paradox is extended by replacing its assumption of time reversibility with full CPT symmetry. Mobility is identified as a means for expressing collisions or dissipation, and the cross product of its gradient with the magnetic field, for expressing parity. Three phenomena incorporating such cross products are identified. The first is the cross product of the mobility gradient with the magnetic field. The second combines this cross product with the E cross B drift. The third is the reciprocal of the Nernst effect expressed as a cross product of the temperature gradient and the magnetic field. Simulations are conducted for testing Loschmidt’s extended paradox. Onsager’s exclusion of magnetic fields and rotation from reciprocals violates CPT symmetry and is unjustified. All three cross-product phenomena skew statistics in a fashion unanticipated by Boltzmann’s assumptions in his H-Theorem. CPT symmetric systems fall outside the assumptions of the theorem which is not rendered invalid but simply limited to its domain of applicability. Therefore, these systems do not violate the second law as Boltzmann defines it. They bypass it.
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A Faraday isolator is shown to develop a temperature difference between its input and output, but still complies with the second law when all the heat carriers, in this case, photons are homogeneous and indistinguishable. This result is a consequence of the H-theorem which assumes homogeneity and indistinguishability of particles. However, when a thermal feedback path is added, in which heat carriers have physical properties different from the photons in the isolator, then a heterogeneous system is formed not covered by the H-theorem, and the second law is violated.
文摘A Faraday isolator is shown to develop a temperature difference between its input and output, but still complies with the second law when all the heat carriers, in this case, photons are homogeneous and indistinguishable. This result is a consequence of the H-theorem which assumes homogeneity and indistinguishability of particles. However, when a thermal feedback path is added, in which heat carriers have physical properties different from the photons in the isolator, then a heterogeneous system is formed not covered by the H-theorem, and the second law is violated.
文摘We propose a reformulation of Newton’s second law of motion for charged particles and possible applications of the reformulation to quantum dynamics. We show that the negative energy states arising from the Dirac equation in relativistic quantum mechanics can be verified using the reformulating framework. We also discuss possible hidden dynamics underlying the concept of quantum jumps in quantum mechanics as outlined in Schr<span style="font-size:12px;white-space:nowrap;">ö</span>dinger’s article: ARE THERE QUANTUM JUMPS? In this case, we show that the hidden dynamics of quantum jumps are also determined by the Coulomb interaction between charged particles.
基金Supported by Shanghai Leading Academic Displine Project(No.B604)
文摘Refrigeration coefficient,ε,is usually calculated by using the First Law of Thermodynamics.In this paper,a new derivation process is introduced through the combination of the Second Law of Thermodynamics with the First Law of Thermodynamics.As a result,two new calculation equations for refrigeration coefficient are proposed.One equation is equivalent to the common method,but its form is a little complicated for real calculation.Another equation is the further simplification,and can be used to calculate the refrigeration coefficient instead of common method with a permit error.
文摘Based on the entropy generation concept of thermodynamics, this paper established a general theoretical model for the analysis of entropy generation to optimize fins, in which the minimum entropy generation was selected as the object to be studied. The irreversibility due to heat transfer and friction was taken into account so that the minimum entropy generation number has been analyzed with respect to second law of thermodynamics in the forced cross-flow. The optimum dimensions of cylinder pins were discussed. It’s found that the minimum entropy generation number depends on parameters related to the fluid and fin physical parameters. Variations of the minimum entropy generation number with different parameters were analyzed.
