Maximum rate of food consumption (C max) was determined for juvenile Sebastodes fuscescens (Houttuyn) at water temperature of 10, 15, 20 and 25℃. The relationships of C max to the body weight (W) at each temperature ...Maximum rate of food consumption (C max) was determined for juvenile Sebastodes fuscescens (Houttuyn) at water temperature of 10, 15, 20 and 25℃. The relationships of C max to the body weight (W) at each temperature were described by a power equation: lnC max = a + b lnW. Covariance analysis revealed significant interaction of the temperature and body weight. The relationship of adjusted C max to water temperature (T) was described by a quadratic equation: C max =-0.369 + 0.456T - 0.0117T 2. The optimal feeding temperature calculated from this equation was 19.5℃. The coefficients of the multiple regression estimation relating C max to body weight (W) and water temperature (T) were given in the Table 2.展开更多
Mass elevation effect （MEE） refers to the thermal effect of huge mountains or plateaus, which causes the tendency for tem- perature-related montane landscape limits to occur at higher elevations in the inner massifs...Mass elevation effect （MEE） refers to the thermal effect of huge mountains or plateaus, which causes the tendency for tem- perature-related montane landscape limits to occur at higher elevations in the inner massifs than on their outer margins. MEE has been widely identified in all large mountains, but how it could be measured and what its main forming-factors are still remain open. This paper, supposing that the local mountain base elevation （MBE） is the main factor of MEE, takes the Qinghai-Tibet Plateau （QTP） as the study area, defines MEE as the temperature difference （AT） between the inner and outer parts of mountain massifs, identifies the main forming factors, and analyzes their contributions to MEE. A total of 73 mountain bases were identified, ranging from 708 m to 5081 m and increasing from the edges to the central parts of the plateau. Climate data （1981-2010） from 134 meteorological stations were used to acquire ATby comparing near-surface air temperature on the main plateau with the free-air temperature at the same altitude and simi- lar latitude outside of the plateau. The AT for the warmest month is averagely 6.15 ~C, over 12~C at Lhatse and Baxoi. A multivariate linear regression model was developed to simulate MEE based on three variables （latitude, annual mean precipitation and MBE）, which are all significantly correlated to AT. The model could explain 67.3% of MEE variation, and the contribution rates of three independent variables to MEE are 35.29%, 22.69% and 42.02%, respectively. This confirms that MBE is the main factor of MEE. The intensive MEE of the QTP pushes the 10~C isotherm of the warmest month mean temperature 1300-2000 m higher in the main plateau than in the outer regions, leading the occurrence of the highest timberline （4900 m） and the highest snowline （6200 m） of the Northern Hemisphere in the southeast and southwest of the plateau, respectively.展开更多
Many kinds of high temperature superconductor （HTS） power machines such as HTS cable, HTS fault current limitcr and HTS magnet are cooled by liquid nitrogen. The level of liquid nitrogen should be monitored and cont...Many kinds of high temperature superconductor （HTS） power machines such as HTS cable, HTS fault current limitcr and HTS magnet are cooled by liquid nitrogen. The level of liquid nitrogen should be monitored and controlled to ensure the thermal stability and the dielectric strength as well. To measure the level, capacitance method and differential pressure method are usually used. However, each method has installation difficulties and measurement errors for unsteady state operation with varying system pressure. A new liquid level meter using a 2G HTS conductor is described, which has similar structure with the liquid helium level meter with NbTi filament. The level meter is fabricated with a parallel connected heater, which helps the separation of the superconducting region and normal region, considering the critical temperature, large heat capacity of conductor and cooling characteristics. The level of liquid nitrogen can be obtained from the measured voltage signal along the 2G HTS conductor. Design, fabrication and test results of the new liquid nitrogen level meter are presented.展开更多
This study investigates the changes in January diurnal temperature range(DTR) in China during 1961-2000.The observed DTR changes during 1981-2000 relative to 1961-80 are first analyzed based on the daily temperature d...This study investigates the changes in January diurnal temperature range(DTR) in China during 1961-2000.The observed DTR changes during 1981-2000 relative to 1961-80 are first analyzed based on the daily temperature data at 546 weather stations.These observed DTR changes are classified into six cases depending on the changes in daily maximum and minimum temperatures,and then the occurrence frequency and magnitude of DTR change in each case are presented.Three transient simulations are then performed to understand the impact of greenhouse gases(GHGs) and aerosol direct forcing on DTR change:one without anthropogenic radiative forcing,one with anthropogenic GHGs,and another one with the combined forcing of GHGs and five species of anthropogenic aerosols.The predicted daily DTR changes during the years 1981-2000 are also classified into six cases and are compared with the observations.Results show that the previously proposed reason for DTR reduction,a stronger nocturnal warming than a daytime warming,explains only 19.8%of the observed DTR reduction days.DTR reductions are found to generally occur in northeastern China,coinciding with significant regional warming.The simulation with GHG forcing alone reproduces this type of DTR reduction with an occurrence frequency of 32.9%,which is larger than the observed value.Aerosol direct forcing reduces DTR mainly by daytime cooling.Consideration of aerosol cooling improves the simulation of occurrence frequencies of different types of DTR changes as compared to the simulation with GHGs alone,but it cannot improve the prediction of the magnitude of DTR changes.展开更多
To study the influence of the Soret and Dufour effects on the reactive characteristics of a porous packed bed with endothermic reactions and forced convection, a two-dimensional mathematical model considering the cros...To study the influence of the Soret and Dufour effects on the reactive characteristics of a porous packed bed with endothermic reactions and forced convection, a two-dimensional mathematical model considering the cross-diffusion effects was developed in accordance with the thermodynamics of irreversible processes and the local thermal non-equilibrium model. The simulation results were validated by comparing with experimental data. The influence of the Soret and Dufour effects on the heat transfer, mass transfer and endothermic chemical reaction in the non-thermal equilibrium packed bed is discussed. It was found that when the Peclet number reaches 1865, the maximum relative error of the concentration of gas product induced by the Soret effect is 34.7% and that of the solid fractional conversion caused by the Dufour effect is 10.8% at reaction time 160 s and initial temperature 1473 K. The differences induced by the Soret and Dufour effects are demonstrated numerically to increase gradually with the initial temperature of feeding gas and the Peclet number.展开更多
Analyzing the effects of heat rejection from condensers of split-type air-conditioning units at lower-floors of MLABs （multi-level apartment buildings）, using field measurements to monitor environmental conditions a...Analyzing the effects of heat rejection from condensers of split-type air-conditioning units at lower-floors of MLABs （multi-level apartment buildings）, using field measurements to monitor environmental conditions and condenser operation, revealed increases in the inlet air temperature at the condensers at the upper floors, which in turn increased the power and energy requirements for these units and decreased their cooling capacities. Results indicated that a decrease of up to 16,000 tons in cooling capacity and an increase of up to 67.2 MW in the national peak load demand might be reached for a 4 ℃ temperature differential for Kuwait conditions. It is recommended that the condensers be placed in the wind pathway to minimize the impact of heat rejection and stack effect and to optimize the operation of split-type air-conditioning units, and that other factors regarding installation setup and location are investigated.展开更多
Climate change is the main problem of mankind, especially because of it＇s increasing speed and by specialists＇ forecast the situation will become worse. Climatic changes are correlated with the degradation of biosph...Climate change is the main problem of mankind, especially because of it＇s increasing speed and by specialists＇ forecast the situation will become worse. Climatic changes are correlated with the degradation of biosphere. It is a question of saving life on authors planet. The authors should begin taking strong measures, else Earth has a chance to repeat the destiny of Mars and Venus, as some scientists are afraid of. So reasoning like ＂When will it be and will it be at all＂ is for lazy, careless and selfish people. Now, because of the industrial emission of greenhouse gases, the temperature of the atmosphere is growing, the climate is changing： sudden temperature differences, snowfalls where it used to be impossible, thickness of arctic ice decrease is about 40% （a great ice-hole has been found on the north pole）, repetition of droughts has increased in 8 times, power of hurricanes-2 times, increased power of floods. This is the result of lack of foresight, over-materialism and greediness, unwillingness to see the consequences because of the momentary advantages. How it is possible to trap CO2, SO2 and other gases？ Commercially gas purification at thermoelectric power stations, ferrous and non-ferrous metallurgy plants, cement and chemical plants is being made with filters and cyclones that trap solid parts, and using different absorptive and adsorptive methods. Unfortunately at present there is no effective method of COE trapping.展开更多
Based on monthly mean surface air temperature （SAT） from 71 stations in northern China and NCEP/ NCAR and NOAA-CIRES （Cooperative Institute for Research in Environmental Sciences） twentieth century reanalysis data...Based on monthly mean surface air temperature （SAT） from 71 stations in northern China and NCEP/ NCAR and NOAA-CIRES （Cooperative Institute for Research in Environmental Sciences） twentieth century reanalysis data, the dominant modes of winter SAT over northem China were explored. The results showed that there are two modes that account for a majority of the total variance over northern China. The first mode is unanimously colder （warmer） over the whole of northern China. The second mode is characterized by a dipole structure that is colder （warmer） over Northwest China （NWC） and warmer （colder） over Northeast China （NEC）, accounting for a fairly large proportion of the total variance. The two components constituting the second mode, the individual variations of winter SAT over NWC and NEC and their respective preceding factors, were further investigated. It was found that the autumn SAT anomalies are closely linked to persistent snow cover anomalies over Eurasia, showing the delayed effects on winter climate over northern China. Specifically, the previous autumn SAT anomalies over the Lake Baikal （LB; 50-60°N, 85-120°E） and Mongolian Plateau （MP; 42-52°N, 80-120°E） regions play an important role in adjusting the variations of winter SAT over NWC and NEC, respectively. The previous autumn SAT anomaly over the MP region may exert an influence on the winter SAT over NEC through modulating the strength and location of the East Asian major trough. The previous autumn SAT over the LB region may modulate winter westerlies at the middle and high latitudes of Asia and accordingly affects the invasion of cold air and associated winter SAT over NWC.展开更多
This study compares CH4 emissions from different livestock farms （poultry, cattle and swine farms） in Enugu, Eastern Nigeria. Data on animal type, number and age were obtained by direct observations while the concen...This study compares CH4 emissions from different livestock farms （poultry, cattle and swine farms） in Enugu, Eastern Nigeria. Data on animal type, number and age were obtained by direct observations while the concentrations of CH4 in the livestock farms were measured with the Gasman Crowcrown Gas Monitor. Daily ambient air temperature and rainfall data were obtained from the Nigerian Meteorological Agency （NIMET） Enugu. Regression analysis was used to determine possible relationships existing between weather parameters and CH4 emissions while the One-Way ANOVA was used to determine variance equality in means of greenhouse gas emission spatially at P 〈 0.05. Minimum and maximum temperatures ranged between 21.9 and 22.7 ℃ and 26.2 and 30.6 ℃ respectively, with rainfall ranging between 0.0 and 12.5 mm during the study period. Of the livestock farms sampled, swine farm emitted the highest concentrations of the greenhouse gas at both the livestock house （2.88 ± 0.28 ppm） and feaces decomposition site （2.30 ±0.30 ppm）, while poultry emitted the least concentrations of 1.96 ± 0.23 and 1.92 ± 0.10 ppm in the livestock house and faeces decomposition locations respectively. Age and number of livestock did not affect emissions of greenhouse gas. Though the prevailing weather parameters measured （temperature and rainfall） did not exert significant influences on greenhouse gas emissions, significant spatial variations in emissions in the feaces decomposition sites of the farmhouses was observed at P 〈 0.05. CH4emission in cattle farmhouse （2.80 ± 0.46 ppm） and swine farmhouse （2.88 ± 0.28 ppm） as well as those measured in the faeces decomposition locations of swine farmhouse （2.30 ± 0.30 ppm） exceeded the CH4 concentration level of 2.0 ppm measured in dry air at sea level. There is need for a further research on the effects of animal age, growth rate and biochemistry on CH4 emissions at the farmhouses.展开更多
In the new century, energy and environmental problems are becoming more critical, and the development of natural energy is desired. Low-grade Thermal Energy Conversion(LTEC) is refocused as one of the renewable energy...In the new century, energy and environmental problems are becoming more critical, and the development of natural energy is desired. Low-grade Thermal Energy Conversion(LTEC) is refocused as one of the renewable energy methods. The usefulness of LTEC is expected using hot springs and waste heat. In the case of the Rankine cycle using ammonia as the working fluid, the thermal properties of the working fluid changes in the evaporator. The traditional evaluation method of heat exchanger performance is the LMTD(Logarithmic Mean Temperature Difference) method. On the other hand, the GMTD(Generalized Mean Temperature Difference) method allows the variation of thermal properties in the heat exchanger. The aim of this study is to compare the two methods for the calculation of temperature differences and the corresponding influence on the total performance of the Rankine cycle that is operated using ammonia as a working fluid. As a result, the thermal efficiency of the Rankine cycle is greater than that of the LMTD method. Moreover, the computable range of the GMTD calculation method is less than that of the LMTD calculation method.展开更多
To test the hypothesis that the variance of incubation temperature may have constituted a significant selective force for reptilian viviparity, we incubated eggs of the slender forest skink Scincella modesta in five t...To test the hypothesis that the variance of incubation temperature may have constituted a significant selective force for reptilian viviparity, we incubated eggs of the slender forest skink Scincella modesta in five thermally different natural nests and at two constant temperatures （18℃ and 21 ℃）. Our manipulation of incubation temperature had significant effects on incubation length and several hatchling traits （snout-vent length, tail length, fore-limb length, and sprint speed）, but not on hatching success and other hatchling traits examined （body mass, head size, and hind-limb length）. Incubation length was nonlinearly sensitive to temperature, but it was not correlated with the thermal variance when holding the thermal mean constant. The 18 ℃ treatment not only produced smaller sized hatchlings but also resulted in decreased sprint speed. Eggs in the nest with the greatest proportion of temperatures higher than 28 ℃ also produced smaller sized hatchlings. None of the hatchling traits examined was affected by the thermal variance. Thermal fluctuations did result in longer incubation times, but females would benefit little from maintaining stable body temperatures or selecting thermally stable nests in terms of the reduced incubation length. Our data show that the mean rather than the variance of temperatures has a key role in influencing incubation length and hatchling phenotypes, and thus do not support the hypothesis tested .展开更多
This paper deals with the theoretical investigation of a fundamental problem of magne- tohydrodynamic （MHD） flow of blood in a capillary in the presence of thermal radiation and chemical reaction. The unsteadiness i...This paper deals with the theoretical investigation of a fundamental problem of magne- tohydrodynamic （MHD） flow of blood in a capillary in the presence of thermal radiation and chemical reaction. The unsteadiness in the flow and temperature fields is caused by the time-dependence of the stretching velocity and the surface temperature. The fluid is considered to be non-Newtonian, whose flow is governed by the equation of a third-order fluid. The problem is first reduced to solving a system of coupled nonlinear differential equations involving several parameters. Considering blood as an electrically conducting fluid and using the present analysis, an attempt is made to compute some parameters of the blood flow by developing a suitable numerical method and by devising an appropri- ate finite difference scheme. The computational results are presented in graphical form, and thereby some theoretical predictions are made with respect to the hemodynamical flow of the blood in a hyperthermal state under the action of a magnetic field. Com- putational results for the variation in velocity, temperature, concentration, skin-friction coefi^icient, Nusselt number and Sherwood number are presented in graphical/tabular form. Since the study takes care of thermal radiation in blood flow, the results reported here are likely to have an important bearing on the therapeutic procedure of hyperthermia, particularly in understanding blood flow and heat transfer in capillaries.展开更多
文摘Maximum rate of food consumption (C max) was determined for juvenile Sebastodes fuscescens (Houttuyn) at water temperature of 10, 15, 20 and 25℃. The relationships of C max to the body weight (W) at each temperature were described by a power equation: lnC max = a + b lnW. Covariance analysis revealed significant interaction of the temperature and body weight. The relationship of adjusted C max to water temperature (T) was described by a quadratic equation: C max =-0.369 + 0.456T - 0.0117T 2. The optimal feeding temperature calculated from this equation was 19.5℃. The coefficients of the multiple regression estimation relating C max to body weight (W) and water temperature (T) were given in the Table 2.
基金National Natural Science Foundation of China(No.41571099,41030528)
文摘Mass elevation effect （MEE） refers to the thermal effect of huge mountains or plateaus, which causes the tendency for tem- perature-related montane landscape limits to occur at higher elevations in the inner massifs than on their outer margins. MEE has been widely identified in all large mountains, but how it could be measured and what its main forming-factors are still remain open. This paper, supposing that the local mountain base elevation （MBE） is the main factor of MEE, takes the Qinghai-Tibet Plateau （QTP） as the study area, defines MEE as the temperature difference （AT） between the inner and outer parts of mountain massifs, identifies the main forming factors, and analyzes their contributions to MEE. A total of 73 mountain bases were identified, ranging from 708 m to 5081 m and increasing from the edges to the central parts of the plateau. Climate data （1981-2010） from 134 meteorological stations were used to acquire ATby comparing near-surface air temperature on the main plateau with the free-air temperature at the same altitude and simi- lar latitude outside of the plateau. The AT for the warmest month is averagely 6.15 ~C, over 12~C at Lhatse and Baxoi. A multivariate linear regression model was developed to simulate MEE based on three variables （latitude, annual mean precipitation and MBE）, which are all significantly correlated to AT. The model could explain 67.3% of MEE variation, and the contribution rates of three independent variables to MEE are 35.29%, 22.69% and 42.02%, respectively. This confirms that MBE is the main factor of MEE. The intensive MEE of the QTP pushes the 10~C isotherm of the warmest month mean temperature 1300-2000 m higher in the main plateau than in the outer regions, leading the occurrence of the highest timberline （4900 m） and the highest snowline （6200 m） of the Northern Hemisphere in the southeast and southwest of the plateau, respectively.
基金Project supported by the Second Stage of Brain Korea 21 Projects
文摘Many kinds of high temperature superconductor （HTS） power machines such as HTS cable, HTS fault current limitcr and HTS magnet are cooled by liquid nitrogen. The level of liquid nitrogen should be monitored and controlled to ensure the thermal stability and the dielectric strength as well. To measure the level, capacitance method and differential pressure method are usually used. However, each method has installation difficulties and measurement errors for unsteady state operation with varying system pressure. A new liquid level meter using a 2G HTS conductor is described, which has similar structure with the liquid helium level meter with NbTi filament. The level meter is fabricated with a parallel connected heater, which helps the separation of the superconducting region and normal region, considering the critical temperature, large heat capacity of conductor and cooling characteristics. The level of liquid nitrogen can be obtained from the measured voltage signal along the 2G HTS conductor. Design, fabrication and test results of the new liquid nitrogen level meter are presented.
基金supported by the Knowledge Innovation Program of the Chinese Academy of Sciences(Grant Nos.KZCX2-YW-Q11-03 and KZCX2-YW-Q1-02)the National Natural Science Foundation of China(Grant No.40825016)the China Meteorological Administration for the Special Project of Meteorological Sector(Grant No.GYHY200906020)
文摘This study investigates the changes in January diurnal temperature range(DTR) in China during 1961-2000.The observed DTR changes during 1981-2000 relative to 1961-80 are first analyzed based on the daily temperature data at 546 weather stations.These observed DTR changes are classified into six cases depending on the changes in daily maximum and minimum temperatures,and then the occurrence frequency and magnitude of DTR change in each case are presented.Three transient simulations are then performed to understand the impact of greenhouse gases(GHGs) and aerosol direct forcing on DTR change:one without anthropogenic radiative forcing,one with anthropogenic GHGs,and another one with the combined forcing of GHGs and five species of anthropogenic aerosols.The predicted daily DTR changes during the years 1981-2000 are also classified into six cases and are compared with the observations.Results show that the previously proposed reason for DTR reduction,a stronger nocturnal warming than a daytime warming,explains only 19.8%of the observed DTR reduction days.DTR reductions are found to generally occur in northeastern China,coinciding with significant regional warming.The simulation with GHG forcing alone reproduces this type of DTR reduction with an occurrence frequency of 32.9%,which is larger than the observed value.Aerosol direct forcing reduces DTR mainly by daytime cooling.Consideration of aerosol cooling improves the simulation of occurrence frequencies of different types of DTR changes as compared to the simulation with GHGs alone,but it cannot improve the prediction of the magnitude of DTR changes.
基金Supported by the National Natural Science Foundation of China （51004071, 51164015） Special Project for High-end CNC Machine Tools and Basic Manufacturing Equipment of China （2012ZX04007-021） Liaoning Province College Excellent Talents Fund Project （LJQ2013012）
文摘To study the influence of the Soret and Dufour effects on the reactive characteristics of a porous packed bed with endothermic reactions and forced convection, a two-dimensional mathematical model considering the cross-diffusion effects was developed in accordance with the thermodynamics of irreversible processes and the local thermal non-equilibrium model. The simulation results were validated by comparing with experimental data. The influence of the Soret and Dufour effects on the heat transfer, mass transfer and endothermic chemical reaction in the non-thermal equilibrium packed bed is discussed. It was found that when the Peclet number reaches 1865, the maximum relative error of the concentration of gas product induced by the Soret effect is 34.7% and that of the solid fractional conversion caused by the Dufour effect is 10.8% at reaction time 160 s and initial temperature 1473 K. The differences induced by the Soret and Dufour effects are demonstrated numerically to increase gradually with the initial temperature of feeding gas and the Peclet number.
文摘Analyzing the effects of heat rejection from condensers of split-type air-conditioning units at lower-floors of MLABs （multi-level apartment buildings）, using field measurements to monitor environmental conditions and condenser operation, revealed increases in the inlet air temperature at the condensers at the upper floors, which in turn increased the power and energy requirements for these units and decreased their cooling capacities. Results indicated that a decrease of up to 16,000 tons in cooling capacity and an increase of up to 67.2 MW in the national peak load demand might be reached for a 4 ℃ temperature differential for Kuwait conditions. It is recommended that the condensers be placed in the wind pathway to minimize the impact of heat rejection and stack effect and to optimize the operation of split-type air-conditioning units, and that other factors regarding installation setup and location are investigated.
文摘Climate change is the main problem of mankind, especially because of it＇s increasing speed and by specialists＇ forecast the situation will become worse. Climatic changes are correlated with the degradation of biosphere. It is a question of saving life on authors planet. The authors should begin taking strong measures, else Earth has a chance to repeat the destiny of Mars and Venus, as some scientists are afraid of. So reasoning like ＂When will it be and will it be at all＂ is for lazy, careless and selfish people. Now, because of the industrial emission of greenhouse gases, the temperature of the atmosphere is growing, the climate is changing： sudden temperature differences, snowfalls where it used to be impossible, thickness of arctic ice decrease is about 40% （a great ice-hole has been found on the north pole）, repetition of droughts has increased in 8 times, power of hurricanes-2 times, increased power of floods. This is the result of lack of foresight, over-materialism and greediness, unwillingness to see the consequences because of the momentary advantages. How it is possible to trap CO2, SO2 and other gases？ Commercially gas purification at thermoelectric power stations, ferrous and non-ferrous metallurgy plants, cement and chemical plants is being made with filters and cyclones that trap solid parts, and using different absorptive and adsorptive methods. Unfortunately at present there is no effective method of COE trapping.
基金the support of the National Natural Science Foundation of China (Grant Nos. 41375090 and 41375089)the Basic Research Fund of the Chinese Academy of Meteorological Sciences (Grant No. 2013Z002)
文摘Based on monthly mean surface air temperature （SAT） from 71 stations in northern China and NCEP/ NCAR and NOAA-CIRES （Cooperative Institute for Research in Environmental Sciences） twentieth century reanalysis data, the dominant modes of winter SAT over northem China were explored. The results showed that there are two modes that account for a majority of the total variance over northern China. The first mode is unanimously colder （warmer） over the whole of northern China. The second mode is characterized by a dipole structure that is colder （warmer） over Northwest China （NWC） and warmer （colder） over Northeast China （NEC）, accounting for a fairly large proportion of the total variance. The two components constituting the second mode, the individual variations of winter SAT over NWC and NEC and their respective preceding factors, were further investigated. It was found that the autumn SAT anomalies are closely linked to persistent snow cover anomalies over Eurasia, showing the delayed effects on winter climate over northern China. Specifically, the previous autumn SAT anomalies over the Lake Baikal （LB; 50-60°N, 85-120°E） and Mongolian Plateau （MP; 42-52°N, 80-120°E） regions play an important role in adjusting the variations of winter SAT over NWC and NEC, respectively. The previous autumn SAT anomaly over the MP region may exert an influence on the winter SAT over NEC through modulating the strength and location of the East Asian major trough. The previous autumn SAT over the LB region may modulate winter westerlies at the middle and high latitudes of Asia and accordingly affects the invasion of cold air and associated winter SAT over NWC.
文摘This study compares CH4 emissions from different livestock farms （poultry, cattle and swine farms） in Enugu, Eastern Nigeria. Data on animal type, number and age were obtained by direct observations while the concentrations of CH4 in the livestock farms were measured with the Gasman Crowcrown Gas Monitor. Daily ambient air temperature and rainfall data were obtained from the Nigerian Meteorological Agency （NIMET） Enugu. Regression analysis was used to determine possible relationships existing between weather parameters and CH4 emissions while the One-Way ANOVA was used to determine variance equality in means of greenhouse gas emission spatially at P 〈 0.05. Minimum and maximum temperatures ranged between 21.9 and 22.7 ℃ and 26.2 and 30.6 ℃ respectively, with rainfall ranging between 0.0 and 12.5 mm during the study period. Of the livestock farms sampled, swine farm emitted the highest concentrations of the greenhouse gas at both the livestock house （2.88 ± 0.28 ppm） and feaces decomposition site （2.30 ±0.30 ppm）, while poultry emitted the least concentrations of 1.96 ± 0.23 and 1.92 ± 0.10 ppm in the livestock house and faeces decomposition locations respectively. Age and number of livestock did not affect emissions of greenhouse gas. Though the prevailing weather parameters measured （temperature and rainfall） did not exert significant influences on greenhouse gas emissions, significant spatial variations in emissions in the feaces decomposition sites of the farmhouses was observed at P 〈 0.05. CH4emission in cattle farmhouse （2.80 ± 0.46 ppm） and swine farmhouse （2.88 ± 0.28 ppm） as well as those measured in the faeces decomposition locations of swine farmhouse （2.30 ± 0.30 ppm） exceeded the CH4 concentration level of 2.0 ppm measured in dry air at sea level. There is need for a further research on the effects of animal age, growth rate and biochemistry on CH4 emissions at the farmhouses.
文摘In the new century, energy and environmental problems are becoming more critical, and the development of natural energy is desired. Low-grade Thermal Energy Conversion(LTEC) is refocused as one of the renewable energy methods. The usefulness of LTEC is expected using hot springs and waste heat. In the case of the Rankine cycle using ammonia as the working fluid, the thermal properties of the working fluid changes in the evaporator. The traditional evaluation method of heat exchanger performance is the LMTD(Logarithmic Mean Temperature Difference) method. On the other hand, the GMTD(Generalized Mean Temperature Difference) method allows the variation of thermal properties in the heat exchanger. The aim of this study is to compare the two methods for the calculation of temperature differences and the corresponding influence on the total performance of the Rankine cycle that is operated using ammonia as a working fluid. As a result, the thermal efficiency of the Rankine cycle is greater than that of the LMTD method. Moreover, the computable range of the GMTD calculation method is less than that of the LMTD calculation method.
基金The work was carried out in compliance with the current laws of China, and was supported by grant from Priority Academic Program Development of Jiangsu Higher Education Institutions to Ji＇s group, the Natural Science Foundation of the Jiangsu Higher Education Institutions of China （Project No. llKJB180004）, Jiangsu Provincial Foundation of Natural Science （No. BK2012849） and the Natural Science Foundation of China （No. 31070339）. We would like to thank Long-Hui Lin, Jian-Fang Gao, Lai-Gao Luo andYan-Fu Qu for their assistance both in the field and in the laboratory.
文摘To test the hypothesis that the variance of incubation temperature may have constituted a significant selective force for reptilian viviparity, we incubated eggs of the slender forest skink Scincella modesta in five thermally different natural nests and at two constant temperatures （18℃ and 21 ℃）. Our manipulation of incubation temperature had significant effects on incubation length and several hatchling traits （snout-vent length, tail length, fore-limb length, and sprint speed）, but not on hatching success and other hatchling traits examined （body mass, head size, and hind-limb length）. Incubation length was nonlinearly sensitive to temperature, but it was not correlated with the thermal variance when holding the thermal mean constant. The 18 ℃ treatment not only produced smaller sized hatchlings but also resulted in decreased sprint speed. Eggs in the nest with the greatest proportion of temperatures higher than 28 ℃ also produced smaller sized hatchlings. None of the hatchling traits examined was affected by the thermal variance. Thermal fluctuations did result in longer incubation times, but females would benefit little from maintaining stable body temperatures or selecting thermally stable nests in terms of the reduced incubation length. Our data show that the mean rather than the variance of temperatures has a key role in influencing incubation length and hatchling phenotypes, and thus do not support the hypothesis tested .
文摘This paper deals with the theoretical investigation of a fundamental problem of magne- tohydrodynamic （MHD） flow of blood in a capillary in the presence of thermal radiation and chemical reaction. The unsteadiness in the flow and temperature fields is caused by the time-dependence of the stretching velocity and the surface temperature. The fluid is considered to be non-Newtonian, whose flow is governed by the equation of a third-order fluid. The problem is first reduced to solving a system of coupled nonlinear differential equations involving several parameters. Considering blood as an electrically conducting fluid and using the present analysis, an attempt is made to compute some parameters of the blood flow by developing a suitable numerical method and by devising an appropri- ate finite difference scheme. The computational results are presented in graphical form, and thereby some theoretical predictions are made with respect to the hemodynamical flow of the blood in a hyperthermal state under the action of a magnetic field. Com- putational results for the variation in velocity, temperature, concentration, skin-friction coefi^icient, Nusselt number and Sherwood number are presented in graphical/tabular form. Since the study takes care of thermal radiation in blood flow, the results reported here are likely to have an important bearing on the therapeutic procedure of hyperthermia, particularly in understanding blood flow and heat transfer in capillaries.
