Green building practices benefit many users because it imposes less of a burden both on people and the environment and plays a central role in achieving a sustainable lifestyle. Covering rooftops with tall evergreen t...Green building practices benefit many users because it imposes less of a burden both on people and the environment and plays a central role in achieving a sustainable lifestyle. Covering rooftops with tall evergreen trees increases evaporation and reduces energy consumption by heating and air conditioning systems. Japan has a cereal-crop culinary culture and rice cultivation is a primary activity. According to the Biophilia Hypothesis exposure to a lush greenery environment conducive to survival facilitates more effective relaxation and recovery from fatigue than simple elimination of stress. The impact of rice paddies is not only about reduction of energy consumption, but also about mitigating the urban environment and its physiological and psychological effects on the human body. Focusing on the spread of the rice canopy and exposure of water surfaces, clarified the reaction of the human body to thermal sensory perception and outdoor thermal environments, and the correlation between them. Rice fields where the rice canopy was smaller, and where ample standing water surfaces received short wavelength solar radiation, have a high heat capacity, which works to increase the longwave length thermal radiation in the time period when the accumulated amount of short wavelength solar radiation increases. Meanwhile, where the spread of the rice canopy was greater, and the surface of the standing irrigation water covered with rice plants, a mitigation effect on the outdoor thermal environment evaluation index of<em> ETFe</em> (enhanced conduction-corrected modified effective temperature) through reduction of long wavelength thermal radiation came into play, and it became clear that thermal sensory perception improved through visual stimuli that engendered images of humidity. The purpose of this study was to clarify the environmental mitigation effect of rice fields in an urban environment. In addition to the physical environmental mitigation effect, it was also shown that rice fields engendered a psychological environment展开更多
The results of this article can be useful in science and technology advancement, such as nanofluidics, micro mixing and energy conversion. The purpose of this article is to examine the impacts of nanoparticle shape on...The results of this article can be useful in science and technology advancement, such as nanofluidics, micro mixing and energy conversion. The purpose of this article is to examine the impacts of nanoparticle shape on Al2O3-water nanofluid and heat transfer over a non-linear radically stretching sheet in the existence of magnetic field and thermal radiation. The different shapes of Al2O3 nanoparticles that have under contemplation are column, sphere, hexahedron, tetrahedron, and lamina. The governing partial differential equations (PDEs) of the problem are regenerated into set of non-linear ordinary differential equations (ODEs) by using appropriate similarity transformation. The bvp4c program has used to solve the obtained non-linear ordinary differential equation (ODEs). The Nusselt number for all shapes of Al2O3 nanoparticle shapes in pure water with is presented in graphical form. It has reported that the heat transfer augmentation in lamina shapes nanoparticles is more than other shapes of nanoparticle. The relation of thermal boundary layer with shapes of nanoparticles, solid volume fraction, magnetic field and thermal radiation has also presented with the help of graphical representation. It is also demonstrated that lamina shape nanoparticles have showed large temperature distribution than other shapes of nanoparticles.展开更多
Land use and land cover(LULC)alteration has changed original energy balance and heat fluxes between land and atmosphere,and thus affects the structure characteristics of temperature and humidity fields over urban hete...Land use and land cover(LULC)alteration has changed original energy balance and heat fluxes between land and atmosphere,and thus affects the structure characteristics of temperature and humidity fields over urban heterogeneous surfaces in different spatio-temporal scales.Lanzhou is the most typical river valley city of China,it is chosen as the case study.Typical river valley terrain,rapid urbanization and severe air pollution have caused unique urban climate and urban heat island(UHI)effects in Lanzhou.Firstly,the spatial structure characteristics and dynamic evolution of temperature and humidity fields in autumn are simulated by mobile measurement experiment and GIS spatial analysis method.The results show that temperature and humidity fields have significant dynamic change within a day,and have multiple center and multiple intensity level characteristics.Then,LULC and normalized difference vegetation index(NDVI)are extracted from remote sensing images,the distribution patterns of temperature and humidity fields have close relationships with LULC and NDVI.Moreover,there is a significant positive correlation between impervious surface area and thermal field intensity.A positive correlation between NDVI value and humidity field intensity has been found as well as a negative correlation between NDVI value and thermal field intensity.Finally,heat fluxes and energy balance characteristics between ground and atmosphere are analyzed based on the Bowen-ratio System experiments.This study could provide theoretical support and practical guidance for urban planning,urban eco-environment construction and air pollution prevention of river valley city.展开更多
This study extends the investigation of quantum dissipative effects of a cosmological scalar field by taking into account cosmic expansion and contraction.Cheung,Drewes,Kang,and Kim calculated the effective action and...This study extends the investigation of quantum dissipative effects of a cosmological scalar field by taking into account cosmic expansion and contraction.Cheung,Drewes,Kang,and Kim calculated the effective action and quantum dissipative effects of a cosmological scalar field in a recent work,where analytical expressions for the effective potential and damping coefficient were presented using a simple scalar model with quartic interactions,and the work was conducted using Minkowski-space propagators in loop diagrams.In this work,we incorporate the Hubble expansion and contraction of the cosmic background and focus on the thermal dynamics of a scalar field in a regime where the effective potential changes slowly.Given that the Hubble parameter,H,attains a small but non-zero value,we carry out calculations to the first order in H.If we set H=0,all results match those in flat spacetime.Interestingly,we must integrate over the resonances,which in turn leads to an amplification of the effects of a non-zero H.This is an intriguing phenomenon,which cannot be uncovered in flat spacetime.The implications on particle creations in the early universe will be studied in a forthcoming study.展开更多
We investigate the photon polarization tensor at finite temperatures in the presence of a static and homogeneous external magnetic field.In our scheme,the summing of the Matsubara frequency is performed after Poisson ...We investigate the photon polarization tensor at finite temperatures in the presence of a static and homogeneous external magnetic field.In our scheme,the summing of the Matsubara frequency is performed after Poisson resummation,which is easily completed and converges quickly.Moreover,the behaviors of finite Landau levels are presented explicitly.It shows a convergence while summing infinite Landau levels.Consequently,there is no necessity to truncate the Landau level in a numerical estimation.At zero temperature,the lowest Landau level(LLL)approximation is analytically satisfied for the vacuum photon polarization tensor.However,we examine that the LLL approximation is not enough for the thermal polarization tensor.The thermal tensor obtains non-trivial contributions from the finite-n Landau levels.And,photon spectra gains a large imaginary contribution in thermal medium,which is the so-called Landau damping.Finally,it is argued that the summation of Matsubara frequency is not commuted with Landau level ones,such conjecture is excluded in our calculations.展开更多
文摘Green building practices benefit many users because it imposes less of a burden both on people and the environment and plays a central role in achieving a sustainable lifestyle. Covering rooftops with tall evergreen trees increases evaporation and reduces energy consumption by heating and air conditioning systems. Japan has a cereal-crop culinary culture and rice cultivation is a primary activity. According to the Biophilia Hypothesis exposure to a lush greenery environment conducive to survival facilitates more effective relaxation and recovery from fatigue than simple elimination of stress. The impact of rice paddies is not only about reduction of energy consumption, but also about mitigating the urban environment and its physiological and psychological effects on the human body. Focusing on the spread of the rice canopy and exposure of water surfaces, clarified the reaction of the human body to thermal sensory perception and outdoor thermal environments, and the correlation between them. Rice fields where the rice canopy was smaller, and where ample standing water surfaces received short wavelength solar radiation, have a high heat capacity, which works to increase the longwave length thermal radiation in the time period when the accumulated amount of short wavelength solar radiation increases. Meanwhile, where the spread of the rice canopy was greater, and the surface of the standing irrigation water covered with rice plants, a mitigation effect on the outdoor thermal environment evaluation index of<em> ETFe</em> (enhanced conduction-corrected modified effective temperature) through reduction of long wavelength thermal radiation came into play, and it became clear that thermal sensory perception improved through visual stimuli that engendered images of humidity. The purpose of this study was to clarify the environmental mitigation effect of rice fields in an urban environment. In addition to the physical environmental mitigation effect, it was also shown that rice fields engendered a psychological environment
文摘The results of this article can be useful in science and technology advancement, such as nanofluidics, micro mixing and energy conversion. The purpose of this article is to examine the impacts of nanoparticle shape on Al2O3-water nanofluid and heat transfer over a non-linear radically stretching sheet in the existence of magnetic field and thermal radiation. The different shapes of Al2O3 nanoparticles that have under contemplation are column, sphere, hexahedron, tetrahedron, and lamina. The governing partial differential equations (PDEs) of the problem are regenerated into set of non-linear ordinary differential equations (ODEs) by using appropriate similarity transformation. The bvp4c program has used to solve the obtained non-linear ordinary differential equation (ODEs). The Nusselt number for all shapes of Al2O3 nanoparticle shapes in pure water with is presented in graphical form. It has reported that the heat transfer augmentation in lamina shapes nanoparticles is more than other shapes of nanoparticle. The relation of thermal boundary layer with shapes of nanoparticles, solid volume fraction, magnetic field and thermal radiation has also presented with the help of graphical representation. It is also demonstrated that lamina shape nanoparticles have showed large temperature distribution than other shapes of nanoparticles.
基金National Natural Science Foundation of China,No.U1404401,No.41771202Natural Science Foundation of Henan Province,No.182300410129Open Fund of Henan Key Laboratory of Integrated Air Pollution Control and Ecological Security,No.20170201。
文摘Land use and land cover(LULC)alteration has changed original energy balance and heat fluxes between land and atmosphere,and thus affects the structure characteristics of temperature and humidity fields over urban heterogeneous surfaces in different spatio-temporal scales.Lanzhou is the most typical river valley city of China,it is chosen as the case study.Typical river valley terrain,rapid urbanization and severe air pollution have caused unique urban climate and urban heat island(UHI)effects in Lanzhou.Firstly,the spatial structure characteristics and dynamic evolution of temperature and humidity fields in autumn are simulated by mobile measurement experiment and GIS spatial analysis method.The results show that temperature and humidity fields have significant dynamic change within a day,and have multiple center and multiple intensity level characteristics.Then,LULC and normalized difference vegetation index(NDVI)are extracted from remote sensing images,the distribution patterns of temperature and humidity fields have close relationships with LULC and NDVI.Moreover,there is a significant positive correlation between impervious surface area and thermal field intensity.A positive correlation between NDVI value and humidity field intensity has been found as well as a negative correlation between NDVI value and thermal field intensity.Finally,heat fluxes and energy balance characteristics between ground and atmosphere are analyzed based on the Bowen-ratio System experiments.This study could provide theoretical support and practical guidance for urban planning,urban eco-environment construction and air pollution prevention of river valley city.
基金Supported in parts by the NSF China(11775110,11690034)the European Union’s Horizon 2020 research and innovation programme(RISE)under the Marie Sk′lodowska-Curie grant agreement(644121)the Priority Academic Program Development for Jiangsu Higher Education Institutions(PAPD)。
文摘This study extends the investigation of quantum dissipative effects of a cosmological scalar field by taking into account cosmic expansion and contraction.Cheung,Drewes,Kang,and Kim calculated the effective action and quantum dissipative effects of a cosmological scalar field in a recent work,where analytical expressions for the effective potential and damping coefficient were presented using a simple scalar model with quartic interactions,and the work was conducted using Minkowski-space propagators in loop diagrams.In this work,we incorporate the Hubble expansion and contraction of the cosmic background and focus on the thermal dynamics of a scalar field in a regime where the effective potential changes slowly.Given that the Hubble parameter,H,attains a small but non-zero value,we carry out calculations to the first order in H.If we set H=0,all results match those in flat spacetime.Interestingly,we must integrate over the resonances,which in turn leads to an amplification of the effects of a non-zero H.This is an intriguing phenomenon,which cannot be uncovered in flat spacetime.The implications on particle creations in the early universe will be studied in a forthcoming study.
基金supported by the Major State Basic Research Development Program in,China(No.2015CB856903)supported by the NSFC under Grant Nos.11725523,11735007 and 11261130311(CRC 110 by DFG and NSFC)。
文摘We investigate the photon polarization tensor at finite temperatures in the presence of a static and homogeneous external magnetic field.In our scheme,the summing of the Matsubara frequency is performed after Poisson resummation,which is easily completed and converges quickly.Moreover,the behaviors of finite Landau levels are presented explicitly.It shows a convergence while summing infinite Landau levels.Consequently,there is no necessity to truncate the Landau level in a numerical estimation.At zero temperature,the lowest Landau level(LLL)approximation is analytically satisfied for the vacuum photon polarization tensor.However,we examine that the LLL approximation is not enough for the thermal polarization tensor.The thermal tensor obtains non-trivial contributions from the finite-n Landau levels.And,photon spectra gains a large imaginary contribution in thermal medium,which is the so-called Landau damping.Finally,it is argued that the summation of Matsubara frequency is not commuted with Landau level ones,such conjecture is excluded in our calculations.