[Objective] The aim was to study air temperature changes and urbanization contribution ration in Kunming City in recent 50 years. [ Method] The observation data of air temperature series from Kunming station and other...[Objective] The aim was to study air temperature changes and urbanization contribution ration in Kunming City in recent 50 years. [ Method] The observation data of air temperature series from Kunming station and other four surrounding meteorological stations were used to in- vestigate air temperature variation in Kunming station affected by urbanization during 1960 -2009. [ Result] The trend slope of mean annual temper- ature was 0.402 ~（3/10 a in Kunming station and 0. 103 ~C/10 a in other four surrounding meteorological stations, and the increasing magnitude of air temperature in Kunming station was more than 3 times that of average global warming in the past 50 year. The effect of urbanization on mean an- nual temperature in Kunming station started from 1990. During 1990 -1994, the increasing contribution rate of urbanization to air temperature in Kunming station was less than 40%. From 1995 to 2009, the contribution ratio was more than 50%, up to about 60% in all seasons. Urban heat is- land effect in Kunming station was intensified with the development of urbanization. In addition, the warming rate caused by urban heat island effect in Kunming station was the greatest in dry season, followed by mean annual temperature, and it was the weakest in rainy season. [ Conclusion] The study provided theoretical foundation for future research.展开更多
Histopathological alterations induced by the sublethal concentration of (0.03 ppm) mercuric chloride solution on the epidermis of the fresh-water catfish Heteropneuates fossilis have been studied. It induces slow but ...Histopathological alterations induced by the sublethal concentration of (0.03 ppm) mercuric chloride solution on the epidermis of the fresh-water catfish Heteropneuates fossilis have been studied. It induces slow but significant histopathological changes in the various cellular components of the epidermis. It induces vacuolization, necrosis and pycnosis of the nuclei of the epithelial cells which subsequently shed. Loosening of epithelial cells of the outermost and middle layers following degeneration of the intercellular material and widened intercellular spaces is another important alteration. Prolonged mercury treatment also causes a gradual decrease in staining intensity for sulphated glycosaminoglycans in the outer border of the most superficial layer epithelial cells. The glandular elements (club cells and mucocytes) also get affected, showing cyclic degeneration followed by regeneration.展开更多
A demand for renewable alternatives that would be able to deal with the problems related to well-being is directly linked to the world’s growing needs to save energy and reduce environmental costs. For a project impl...A demand for renewable alternatives that would be able to deal with the problems related to well-being is directly linked to the world’s growing needs to save energy and reduce environmental costs. For a project implementation addressing these issues, it is essential to know the climatic conditions of the target area. Taking natural ventilation, climatic factors, and renewable alternatives as important sources of comfort, in this work, passive strategies, through the utilization of microclimate elements as well as the location of outside obstacles, were imposed on an initial and specific project. The objective was to introduce obstacles which could interfere in the field of external wind and evaluate whether this outside intervention is able to make changes in indoor air circulation. The wind fields for the studied cases were obtained by computational simulations, and their consequences were analyzed to attain thermal comfort. The method adopted to obtain the wind fields was a Petrov-Galerkin type method, which is a stabilized mixed finite element method of the Navier-Stokes equations considering the incompressibility and formulated in primitive variables, velocity and pressure. The obtained results point to the solutions that promote the increase or decrease of the wind-field intensity.展开更多
In order to study the influence of parameters on airborne transmitted diseases in a hospital ward,a pollutant decay equation and a Wells-Riley model are adopted to study the relationship between the airborne infection...In order to study the influence of parameters on airborne transmitted diseases in a hospital ward,a pollutant decay equation and a Wells-Riley model are adopted to study the relationship between the airborne infection risk and the parameters such as the ventilation rate,the number of susceptible persons and the volume of the ward.The results show that the airborne infection risk can be reduced by increasing the ventilation rate.For two wards with the same air change per hour（ACH）but different volumes,the ventilation rate in a large room is higher than that in a small one.The number of the infected persons in the ward increases with the increase in the susceptible persons when the ACH is a constant.Therefore,the ventilation rate in the ward is not only estimated by the ACH but also related to the volume of the ward and the number of the susceptible persons.展开更多
The transmission of coronavirus disease 2019(COVID-19)has presented challenges for the control of the indoor environment of isolation wards.Scientific air distribution design and operation management are crucial to en...The transmission of coronavirus disease 2019(COVID-19)has presented challenges for the control of the indoor environment of isolation wards.Scientific air distribution design and operation management are crucial to ensure the environmental safety of medical staff.This paper proposes the application of adaptive wall-based attachment ventilation and evaluates this air supply mode based on contaminants dispersion,removal efficiency,thermal comfort,and operating expense.Adaptive wall-based attachment ventilation provides a direct supply of fresh air to the occupied zone.In comparison with a ceiling air supply or upper sidewall air supply,adaptive wall-based attachment ventilation results in a 15%–47%lower average concentration of contaminants,for a continual release of contaminants at the same air changes per hour(ACH;10 h^(-1)).The contaminant removal efficiency of complete mixing ventilation cannot exceed 1.For adaptive wall-based attachment ventilation,the contaminant removal efficiency is an exponential function of the ACH.Compared with the ceiling air supply mode or upper sidewall air supply mode,adaptive wall-based attachment ventilation achieves a similar thermal comfort level(predicted mean vote(PMV)of0.1–0.4;draught rate of 2.5%–6.7%)and a similar performance in removing contaminants,but has a lower ACH and uses less energy.展开更多
Change related to climate in Macao was studied on the basis of daily temperature observations over the period 1901-2007. The result shows that annual mean surface air temperature in Macao as a whole rose with a warmin...Change related to climate in Macao was studied on the basis of daily temperature observations over the period 1901-2007. The result shows that annual mean surface air temperature in Macao as a whole rose with a warming rate of about 0.066℃ per 10 years in the recent 107 years. The most evident warming occurred in spring and winter. The interdecadal variations of the seasonal mean temperature in summer and winter appeared as a series of waves with a time scale of about 30 years and 60 years, respectively. The annual mean minimum temperature increased about twice as fast as the annual mean maximum temperature, resulting in a broad decline in the annual mean diurnal range. The interdecadal variations of annual mean maximum temperature are obviously different from those of annual mean minimum temperature. It appears that the increase in the annual mean maximum temperature in the recent 20 years may be part of slow climate fluctuations with a periodicity of about 60 years, whereas that in the annual mean minimum temperature appears to be the continuation of a long-term warming trend.展开更多
The effective radiative forcing （ERF） and associated surface air temperature change over eastern China are estimated using multi-model results from CMIP5 （Coupled Model Intercomparison Project Phase 5）. The model ...The effective radiative forcing （ERF） and associated surface air temperature change over eastern China are estimated using multi-model results from CMIP5 （Coupled Model Intercomparison Project Phase 5）. The model results show that, relative to 1850, the multi-model and annual mean aerosol ERF for the year 2005 is -4.14 W m^-2 at the top of the atmosphere over eastern China （20°-45°N, 105°-122.5°E）. As a result of this ERF, the multi-model and annual mean surface air temperature change in eastern China during 1850-2005 is -1.05℃, leading to a climate sensitivity of 0.24℃/ （Wm^-2） in this region.展开更多
To understand how temperature varies in urban Shanghai under the background of global climate change and how it is affected by urbanization, the Shanghai temperature responses to global warming were analyzed, and then...To understand how temperature varies in urban Shanghai under the background of global climate change and how it is affected by urbanization, the Shanghai temperature responses to global warming were analyzed, and then the temperature trends of urban and suburb stations under different climatic backgrounds were obtained. The urbanization effects on temperature were studied by comparing urban stations to suburb stations, the relationship between urbanization variables and temperature components were obtained, and observation data of surface and high level were combined to assess the contribution of urbanization effect. In the last part of the paper, the cause of urbanization effects on temperature was discussed. The results indicated: The long term change trend of Shanghai annual mean temperature is 1.31/100a from 1873 to 2004, the periods of 1921 – 1948 and 1979 – 2004 are warmer, and the 1979 – 2004 period is the warmest; compared to suburb stations, the representative urban station has slower decreases in the cool period and faster increases in the warm one; the urban and suburb temperatures have distinct differences resulting from urbanization and the differences are increasing by the year, with the difference of mean temperature and minimum temperature being the greatest in fall and that of maximum temperature being the largest in summer between the urban and suburban areas. The urbanization process accelerates the warming speed, with the minimum temperature being the most obvious; the urbanization effect contributes a 0.4°C increase in 1980s and 1.1°C in 1990s to the annual mean temperature.展开更多
At the First Session of the 12th National People＇s Congress, former Premier Wen Jiabao released a series of figures related to China＇s financial growth. Yi Xianrong, a research fellow at the Chinese Academy of Socia...At the First Session of the 12th National People＇s Congress, former Premier Wen Jiabao released a series of figures related to China＇s financial growth. Yi Xianrong, a research fellow at the Chinese Academy of Social Sciences＇ Institute of Finance and Banking, in his article for Securities Daily, crunched those numbers, taking into account the backdrop of China＇s current development. Edited excerpts from his conclusions follow：展开更多
Using radiosonde and satellite observations, we investigated the trends of air temperature changes over the Tibetan Plateau （TP） in comparison with those over other regions in the same latitudes from 1979 to 2002. I...Using radiosonde and satellite observations, we investigated the trends of air temperature changes over the Tibetan Plateau （TP） in comparison with those over other regions in the same latitudes from 1979 to 2002. It is shown that Over the TP, the trends of air temperature changes in the upper troposphere to lower stratosphere were out of phase with those in the lower to middle troposphere. Air temperature decreased and a decreasing trend appeared in the upper troposphere to lower stratosphere. The amplitude of the annual or seasonal mean temperature decreases over the TP was larger than that over the whole globe. In the lower to middle troposphere over the TP, temperature increased, and the increasing trend was stronger than that over the non-plateau regions in the same latitudes in the eastern part of China. Meanwhile, an analysis of the satellite observed ozone data in the same period of 1979-2002 shows that over the TP, the total ozone amount declined in all seasons, and the ozone depleted the most compared with the situations in other regions in the same latitudes. It is proposed that the difference between the ozone depletion over the TP and that over other regions in the same latitudes may lead to the difference in air temperature changes. Because of the aggravated depletion of ozone over the TP, less （more） ultraviolet radiation was absorbed in the upper troposphere to lower stratosphere （lower to middle troposphere） over the TP, which favored a stronger cooling in the upper troposphere to lower stratosphere, and an intenser heating in the lower to middle troposphere over the TP. Therefore, the comparatively more depletion of ozone over the TP is possibly a reason for the difference between the air temperature changes over the TP and those over other regions in the same latitudes.展开更多
A pilot-scale multistage constructed wetland-pond(MCWP)system with a"pre-ecological oxidation pond,two-stage horizontal subsurface flow constructed wetland(HSCW)and surface flow constructed wetland(SFCW)as the co...A pilot-scale multistage constructed wetland-pond(MCWP)system with a"pre-ecological oxidation pond,two-stage horizontal subsurface flow constructed wetland(HSCW)and surface flow constructed wetland(SFCW)as the core and postsubmerged plant pond"as the process was used to treat actual polluted river water in the field,and the variation in nitrogen removal from summer to winter was investigated.The results showed that the average total nitrogen(TN)removal efficiency in the MCWP was approximately 40.74%.The significant positive correlation between the daily highest temperature and the TN removal efficiency of the whole system was fitted with a nonlinear curve(R^(2)=0.7192).The TN removal load rate in the HSCWs was 2.7–3.7 times that in the SFCW.The SFCW,which had high-density plants(35 plants/m^(2)),increased the proportion of nitrogen removed by plant harvesting and microbial function.The TN transformed by Iris pseudacorus L.accounted for 54.53%in the SFCW.Furthermore,bacteria completed the nitrogen cycle in the SFCW through a variety of nitrogen removal pathways.This research not only investigated the TN removal performance in an MCWP system but also made it possible to predict the TN removal efficiency according to the daily highest temperature from summer to winter in the field.展开更多
To explore the energy saving effect of building envelope, the experiments were carried out through a comparison of basic cubicle in summer. Experiments show that if energy efficiency measures are applied only in the e...To explore the energy saving effect of building envelope, the experiments were carried out through a comparison of basic cubicle in summer. Experiments show that if energy efficiency measures are applied only in the external walls and windows, the energy saving cubicles have an average energy efficiency ratio of 27.75% and 27.05% when the air change rates are 1.1 and 1.4 h-1 in summer, with both values being over the standard target value by 25%. And the indoor air temperature of the energy saving cubicle is below that of the basic cubicle. The daily mean temperature difference between the interior surface of insulation wall and no insulation reaches 1.47℃, and the mean temperature difference is up to 8.52℃ between the interior surface and exterior surface of insulating glass and single glass. The two cubicles were simulated for energy consumption using VisualDOE4.0 software under real weather conditions in summer. The results show that the mean deviation is 10.02% between experimental and simulated energy efficiency ratio. The correctness and validity of simulation results of the VisualDOE4.0 software are proved.展开更多
The effect of different extraction and purification conditions on the microbial protein obtained from solid-state fermentation(SSF)and the effect of periodical dynamic changes of air on protein have been studied.The m...The effect of different extraction and purification conditions on the microbial protein obtained from solid-state fermentation(SSF)and the effect of periodical dynamic changes of air on protein have been studied.The mechanism of solid-state fermentation with periodical dynamic changes of air is also discussed.Compared with static solid-state fermentation,periodical dynamic changes of air afford a higher protein mass;from 1 g of the fermentation microbe,5.3 mg of the intracellular protein(an increase of 34.63%)and 9.09 mg of the extracellular protein(an increase of 17.8%)were obtained on the sixth day of fermentation.The filter paper activity and carboxymethyl cellulose activity(FPA and CMCase)of the extracellular protein are 1.739μmol/s and 109.592μmol/s,respectively,which represent increases of 60.1%and 21.2%over the corresponding values for static solid-state fermentation.The FPA and CMCase of the intra-cellular protein are 0.245μmol/s and 6.392μmol/s,respec-tively,which represent decreases of 22.2%and 38.7%over the corresponding values for static solid-state fermentation.The enzyme activity of the microbial extracellular protein in solid-state fermentation with periodical dynamic changes of air on the fifth day is nearly equal to that on the sixth day without periodical dynamic changes of air,so the period of fermentation can be shortened.The sodium dodecyl sulfate-polyacrylamide gel electrophoresis(SDS-PAGE)experiments suggest that pulsating air pressure stimulation leads to a decrease in the amount of protein component with molecule mass of about 80400Da,and an increase in the amount of protein component with molecule mass of about 28520Da.展开更多
Fossil fuel combustion and many industrial processes generate gaseous emissions that contain a number of toxic organic pollutants and carbon dioxide（CO_2） which contribute to climate change and atmospheric pollution...Fossil fuel combustion and many industrial processes generate gaseous emissions that contain a number of toxic organic pollutants and carbon dioxide（CO_2） which contribute to climate change and atmospheric pollution.There is a need for green and sustainable solutions to remove air pollutants,as opposed to conventional techniques which can be expensive,consume additional energy and generate further waste.We developed a novel integrated bioreactor combined with recyclable iron oxide nano/micro-particle adsorption interfaces,to remove CO_2,and undesired organic air pollutants using natural particles,while generating oxygen.This semi-continuous bench-scale photo-bioreactor was shown to successfully clean up simulated emission streams of up to 45% CO_2 with a conversion rate of approximately 4%CO_2 per hour,generating a steady supply of oxygen（6 mmol/hr）,while nanoparticles effectively remove several undesired organic by-products.We also showed algal waste of the bioreactor can be used for mercury remediation.We estimated the potential CO_2 emissions that could be captured from our new method for three industrial cases in which,coal,oil and natural gas were used.With a 30% carbon capture system,the reduction of CO_2 was estimated to decrease by about 420,000,320,000 and 240,000 metric tonnes,respectively for a typical 500 MW power plant.The cost analysis we conducted showed potential to scale-up,and the entire system is recyclable and sustainable.We further discuss the implications of usage of this complete system,or as individual units,that could provide a hybrid option to existing industrial setups.展开更多
Many dwellings in warm-humid climates attain a comfortable environment by natural ventilation.The opening of exterior windows for ventilation allows the entry of insects along with the breeze.As a remedy,occupants ins...Many dwellings in warm-humid climates attain a comfortable environment by natural ventilation.The opening of exterior windows for ventilation allows the entry of insects along with the breeze.As a remedy,occupants install insect-proof screens on windows resulting in reduced airflow into the interior.This study attempts to evaluate the air change effectiveness and thermal comfort in a residential kitchen with insect-proof screens.A kitchen with insect-proof screens on the windows is compared with a case without insect-proof screens.Numerical simulation was conducted using ANSYS Fluent 2019 R2.The insect-proof screen is modelled as a porous media.The air velocity and temperature measurements were validated by measurements in a real scenario.The presence of insect-proof screens reduced the air velocity inside the space by 82%.However,the airflow pattern in the case with screens was more uniformly distributed.The mean age of the air was considerably higher in the case with insect-proof screens,which in turn resulted in a reduced ACE.The presence of an insect-proof screen resulted in a Predicted Mean Vote(PMV)of 2.79 indicating a‘hot’sensation,whereas in the other case,the comfort vote is only 1.93 indicating a‘warm’sensation.The presence of insect-proof screens on windows reduced the air velocity and ventilation efficiency,contributing to increased thermal discomfort in the kitchen.展开更多
The high-level biosafety laboratory is not only the basic support for infectious disease prevention and control,but also interrelated with key areas such as environmental security and social security,which has attract...The high-level biosafety laboratory is not only the basic support for infectious disease prevention and control,but also interrelated with key areas such as environmental security and social security,which has attracted increasing attention.A good indoor environment is the premise to ensure the smooth progress of the experiment and biological risk prevention and control.In order to better understand the indoor environment of high-level biosafety laboratories,19 high-level biosafety laboratories in China(with a total of 65 main rooms)were carefully selected as the test objects from December 2020 to December 2022.According to the test methods specified in the Chinese standard GB 50346,the air change,cleanliness,static pressure difference,temperature,relative humidity,and illumination were tested and analyzed.The results showed that all the measured parameters met the requirements of the Chinese standard GB 50346,and the bio-safety performance was completely satisfactory.However,individual parameters showed some overlarge values:the proportion of main rooms with cleanliness levels of 7 and 8 exceeding 50%of the lower limit for air changes was 54.5%and 69.8%,respectively;the proportion of main rooms in BSL-3-b1 laboratories with atmospheric pressure differentials exceeding 50%of the standard lower limit was 94.7%;and the atmospheric pressure differential in the main rooms of BSL-3-b2 laboratories reached a maximum of nearly-160 Pa.On the premise of ensuring the cleanliness and pressure gradient of the main room,it may be possible to reduce the air change.This study,for the first time,reveals the environmental parameters of various types and levels of biosafety laboratories,which can provide reference for the design and operation of such facilities.展开更多
Previous research was limited to flat-façade buildings when evaluating the indoor and outdoor ventilation performance in a multi-story building.However,envelope features can provide the shading effect to induce t...Previous research was limited to flat-façade buildings when evaluating the indoor and outdoor ventilation performance in a multi-story building.However,envelope features can provide the shading effect to induce the temperature difference between surfaces exposed to direct solar radiation and those without solar radiation.This temperature difference between surfaces can enhance the thermal buoyancy and change indoor and outdoor ventilation performance.We conducted scaled outdoor experiments to examine the impact of various envelope features on indoor and outdoor ventilation performance in multi-story buildings.Compared to the flat-façade multi-building,the average normalized horizontal airflow velocity of overhang,small wing wall,and large wing wall multi-buildings increased by 12.41%,10.56%,and 5.56%,respectively.Cross-ventilation is more susceptible to envelope features than single-sided ventilation in air change per hour(ACH).Specifically,the ACH values of cross-ventilation for large wing wall,small wing wall,and balcony multi-buildings decreased by 69.98%,25.79%,and 12.12%relative to the flat-façade building.For the same envelope feature building,the ACH values of single-sided ventilation on the windward side are better than those on the leeward side,particularly the building with small wing walls,with an improvement of 12.77%compared to flat-façade.This study contributes to advancing the understanding of urban ventilation,and provides a valid basis for designing envelope features in urban buildings.展开更多
Nowadays,the application of renewable energies such as solar energy in the building sector has increased notably considering the adverse impacts of climate change on human life;hence many studies have focused on the a...Nowadays,the application of renewable energies such as solar energy in the building sector has increased notably considering the adverse impacts of climate change on human life;hence many studies have focused on the application of photovoltaic panels in buildings.In the current study,a 3D computational fluid dynamics(CFD)model has been developed to evaluate the performance of a newly designed building-integrated photovoltaic(BIPV)system.Given the negative influence of overheating on the lifespan and performance of PV panels,their passive air cooling has been studied.Further,the potential of rooftop-mounted solar panels in passive ventilation of buildings by generating natural convective currents has been explored.The developed CFD model takes into consideration the effects of radiation,conduction,and buoyancy-driven natural convective currents generated by solar PV panels which are heated due to the exposure to solar radiation heat flux.The results suggest that applying a high surface emissivity for the part of the roof beneath the PV panels intensifies the natural convective currents which in turn provides better cooling for PV panels with higher cooling effects at higher solar heat fluxes.Up to a 34%increase in the convective mass flow rate and a 3 K decrease in the mean temperature of the panels were attained by modifying the emissivity of roof surface.Such a 3 K decrease in the operating temperature of the PV panels can enhance their efficiency and lifespan by about 1.56%and 21%,respectively.Based on the operating conditions and system characteristics,the BIPV system yielded an air change rate(ACH)in the range of 3-13 which was considered to be highly prevalent in providing the required passive ventilation for a wide range of applications.It was also observed that the flow dynamics inside the building were affected by both the amount of solar heat load incident on the solar panels and the emissivity of the roof surface behind the panels.展开更多
Intensive care units(ICUs)are the high incidence sites of hospital-acquired infections,where impinging jet ventilation(IJV)shows great potential.Thermal stratification of IJV and its effect on contaminants distributio...Intensive care units(ICUs)are the high incidence sites of hospital-acquired infections,where impinging jet ventilation(IJV)shows great potential.Thermal stratification of IJV and its effect on contaminants distribution were systematically investigated in this study.By changing the setting of heat source or the air change rates,the main driving force of supply airflow can be transformed between thermal buoyancy and inertial force,which can be quantitatively described by the dimensionless buoyant jet length scale(l_(m)^(-)).For the investigated air change rates,namely 2 ACH to 12 ACH,l_(m)^(-)varies between 0.20 and 2.80.The thermal buoyancy plays a dominant role in the movement of the horizontally exhaled airflow by the infector under low air change rate,where the temperature gradient is up to 2.45℃/m.The flow center remains close to the breathing zone of the susceptible ahead,resulting into the highest exposure risk(6.6‰for 10-μm particles).With higher heat flux of four PC monitors(from 0 W to 125.85 W for each monitor),the temperature gradient in ICU rises from 0.22℃/m to 1.02℃/m;however,the average normalized concentration of gaseous contaminants in the occupied zone is reduced from 0.81 to 0.37,because their thermal plumes are also able to carry containments around them to the ceiling-level readily.As the air change rate was increased to 8 ACH(l_(m)^(-)=1.56),high momentum weakened the thermal stratification by reducing the temperature gradient to 0.37℃/m and exhaled flow readily rose above the breathing zone;the intake fraction of susceptible patient located in front of the infector for 10-μm particles reduces to 0.8‰.This study proved the potential application of IJV in ICUs and provides theoretical guidance for its appropriate design.展开更多
基金Supported by National Natural Science Foundation of Yunnan Province (2011FB009)
文摘[Objective] The aim was to study air temperature changes and urbanization contribution ration in Kunming City in recent 50 years. [ Method] The observation data of air temperature series from Kunming station and other four surrounding meteorological stations were used to in- vestigate air temperature variation in Kunming station affected by urbanization during 1960 -2009. [ Result] The trend slope of mean annual temper- ature was 0.402 ~（3/10 a in Kunming station and 0. 103 ~C/10 a in other four surrounding meteorological stations, and the increasing magnitude of air temperature in Kunming station was more than 3 times that of average global warming in the past 50 year. The effect of urbanization on mean an- nual temperature in Kunming station started from 1990. During 1990 -1994, the increasing contribution rate of urbanization to air temperature in Kunming station was less than 40%. From 1995 to 2009, the contribution ratio was more than 50%, up to about 60% in all seasons. Urban heat is- land effect in Kunming station was intensified with the development of urbanization. In addition, the warming rate caused by urban heat island effect in Kunming station was the greatest in dry season, followed by mean annual temperature, and it was the weakest in rainy season. [ Conclusion] The study provided theoretical foundation for future research.
基金Supported by the University Grants Commission,Govt.of India,New Delhi Project No.F.3-66/89(SR-Ⅱ).
文摘Histopathological alterations induced by the sublethal concentration of (0.03 ppm) mercuric chloride solution on the epidermis of the fresh-water catfish Heteropneuates fossilis have been studied. It induces slow but significant histopathological changes in the various cellular components of the epidermis. It induces vacuolization, necrosis and pycnosis of the nuclei of the epithelial cells which subsequently shed. Loosening of epithelial cells of the outermost and middle layers following degeneration of the intercellular material and widened intercellular spaces is another important alteration. Prolonged mercury treatment also causes a gradual decrease in staining intensity for sulphated glycosaminoglycans in the outer border of the most superficial layer epithelial cells. The glandular elements (club cells and mucocytes) also get affected, showing cyclic degeneration followed by regeneration.
基金the FAPERJ(State of Rio de Janeiro research supporting foundation)
文摘A demand for renewable alternatives that would be able to deal with the problems related to well-being is directly linked to the world’s growing needs to save energy and reduce environmental costs. For a project implementation addressing these issues, it is essential to know the climatic conditions of the target area. Taking natural ventilation, climatic factors, and renewable alternatives as important sources of comfort, in this work, passive strategies, through the utilization of microclimate elements as well as the location of outside obstacles, were imposed on an initial and specific project. The objective was to introduce obstacles which could interfere in the field of external wind and evaluate whether this outside intervention is able to make changes in indoor air circulation. The wind fields for the studied cases were obtained by computational simulations, and their consequences were analyzed to attain thermal comfort. The method adopted to obtain the wind fields was a Petrov-Galerkin type method, which is a stabilized mixed finite element method of the Navier-Stokes equations considering the incompressibility and formulated in primitive variables, velocity and pressure. The obtained results point to the solutions that promote the increase or decrease of the wind-field intensity.
文摘In order to study the influence of parameters on airborne transmitted diseases in a hospital ward,a pollutant decay equation and a Wells-Riley model are adopted to study the relationship between the airborne infection risk and the parameters such as the ventilation rate,the number of susceptible persons and the volume of the ward.The results show that the airborne infection risk can be reduced by increasing the ventilation rate.For two wards with the same air change per hour（ACH）but different volumes,the ventilation rate in a large room is higher than that in a small one.The number of the infected persons in the ward increases with the increase in the susceptible persons when the ACH is a constant.Therefore,the ventilation rate in the ward is not only estimated by the ACH but also related to the volume of the ward and the number of the susceptible persons.
基金supported by the Ministry of Science and Technology of China,the Chinese Academy of Engineering,a project on the risk prevention and control of the relationship between the spread of COVID-19 and the environment(2020YFC0842500 and 2020-ZD-15)the National Key Research and Development(R&D)Program of China(2017YFC0702800).
文摘The transmission of coronavirus disease 2019(COVID-19)has presented challenges for the control of the indoor environment of isolation wards.Scientific air distribution design and operation management are crucial to ensure the environmental safety of medical staff.This paper proposes the application of adaptive wall-based attachment ventilation and evaluates this air supply mode based on contaminants dispersion,removal efficiency,thermal comfort,and operating expense.Adaptive wall-based attachment ventilation provides a direct supply of fresh air to the occupied zone.In comparison with a ceiling air supply or upper sidewall air supply,adaptive wall-based attachment ventilation results in a 15%–47%lower average concentration of contaminants,for a continual release of contaminants at the same air changes per hour(ACH;10 h^(-1)).The contaminant removal efficiency of complete mixing ventilation cannot exceed 1.For adaptive wall-based attachment ventilation,the contaminant removal efficiency is an exponential function of the ACH.Compared with the ceiling air supply mode or upper sidewall air supply mode,adaptive wall-based attachment ventilation achieves a similar thermal comfort level(predicted mean vote(PMV)of0.1–0.4;draught rate of 2.5%–6.7%)and a similar performance in removing contaminants,but has a lower ACH and uses less energy.
文摘Change related to climate in Macao was studied on the basis of daily temperature observations over the period 1901-2007. The result shows that annual mean surface air temperature in Macao as a whole rose with a warming rate of about 0.066℃ per 10 years in the recent 107 years. The most evident warming occurred in spring and winter. The interdecadal variations of the seasonal mean temperature in summer and winter appeared as a series of waves with a time scale of about 30 years and 60 years, respectively. The annual mean minimum temperature increased about twice as fast as the annual mean maximum temperature, resulting in a broad decline in the annual mean diurnal range. The interdecadal variations of annual mean maximum temperature are obviously different from those of annual mean minimum temperature. It appears that the increase in the annual mean maximum temperature in the recent 20 years may be part of slow climate fluctuations with a periodicity of about 60 years, whereas that in the annual mean minimum temperature appears to be the continuation of a long-term warming trend.
基金supported by the National Basic Research Program of China[973 Program,grant number 2014CB441202]the National Natural Science Foundation of China[grant numbers41475137 and 91544219]
文摘The effective radiative forcing （ERF） and associated surface air temperature change over eastern China are estimated using multi-model results from CMIP5 （Coupled Model Intercomparison Project Phase 5）. The model results show that, relative to 1850, the multi-model and annual mean aerosol ERF for the year 2005 is -4.14 W m^-2 at the top of the atmosphere over eastern China （20°-45°N, 105°-122.5°E）. As a result of this ERF, the multi-model and annual mean surface air temperature change in eastern China during 1850-2005 is -1.05℃, leading to a climate sensitivity of 0.24℃/ （Wm^-2） in this region.
文摘To understand how temperature varies in urban Shanghai under the background of global climate change and how it is affected by urbanization, the Shanghai temperature responses to global warming were analyzed, and then the temperature trends of urban and suburb stations under different climatic backgrounds were obtained. The urbanization effects on temperature were studied by comparing urban stations to suburb stations, the relationship between urbanization variables and temperature components were obtained, and observation data of surface and high level were combined to assess the contribution of urbanization effect. In the last part of the paper, the cause of urbanization effects on temperature was discussed. The results indicated: The long term change trend of Shanghai annual mean temperature is 1.31/100a from 1873 to 2004, the periods of 1921 – 1948 and 1979 – 2004 are warmer, and the 1979 – 2004 period is the warmest; compared to suburb stations, the representative urban station has slower decreases in the cool period and faster increases in the warm one; the urban and suburb temperatures have distinct differences resulting from urbanization and the differences are increasing by the year, with the difference of mean temperature and minimum temperature being the greatest in fall and that of maximum temperature being the largest in summer between the urban and suburban areas. The urbanization process accelerates the warming speed, with the minimum temperature being the most obvious; the urbanization effect contributes a 0.4°C increase in 1980s and 1.1°C in 1990s to the annual mean temperature.
文摘At the First Session of the 12th National People＇s Congress, former Premier Wen Jiabao released a series of figures related to China＇s financial growth. Yi Xianrong, a research fellow at the Chinese Academy of Social Sciences＇ Institute of Finance and Banking, in his article for Securities Daily, crunched those numbers, taking into account the backdrop of China＇s current development. Edited excerpts from his conclusions follow：
基金Supported by the National Science Foundation of China under Grant No. 40675058Open Laboratory of Chengdu Institute of Plateau Meteorology, China Meteorological Administration under Grant No. LPM2008007
文摘Using radiosonde and satellite observations, we investigated the trends of air temperature changes over the Tibetan Plateau （TP） in comparison with those over other regions in the same latitudes from 1979 to 2002. It is shown that Over the TP, the trends of air temperature changes in the upper troposphere to lower stratosphere were out of phase with those in the lower to middle troposphere. Air temperature decreased and a decreasing trend appeared in the upper troposphere to lower stratosphere. The amplitude of the annual or seasonal mean temperature decreases over the TP was larger than that over the whole globe. In the lower to middle troposphere over the TP, temperature increased, and the increasing trend was stronger than that over the non-plateau regions in the same latitudes in the eastern part of China. Meanwhile, an analysis of the satellite observed ozone data in the same period of 1979-2002 shows that over the TP, the total ozone amount declined in all seasons, and the ozone depleted the most compared with the situations in other regions in the same latitudes. It is proposed that the difference between the ozone depletion over the TP and that over other regions in the same latitudes may lead to the difference in air temperature changes. Because of the aggravated depletion of ozone over the TP, less （more） ultraviolet radiation was absorbed in the upper troposphere to lower stratosphere （lower to middle troposphere） over the TP, which favored a stronger cooling in the upper troposphere to lower stratosphere, and an intenser heating in the lower to middle troposphere over the TP. Therefore, the comparatively more depletion of ozone over the TP is possibly a reason for the difference between the air temperature changes over the TP and those over other regions in the same latitudes.
基金supported bythe Ministry of Science and Technology of China(No.2015FY110900)the National Natural Science Foundation of China(No.41877409)the Major Science and Technology Program for Water Pollution Control and Treatment of China(No.2018ZX07208008)。
文摘A pilot-scale multistage constructed wetland-pond(MCWP)system with a"pre-ecological oxidation pond,two-stage horizontal subsurface flow constructed wetland(HSCW)and surface flow constructed wetland(SFCW)as the core and postsubmerged plant pond"as the process was used to treat actual polluted river water in the field,and the variation in nitrogen removal from summer to winter was investigated.The results showed that the average total nitrogen(TN)removal efficiency in the MCWP was approximately 40.74%.The significant positive correlation between the daily highest temperature and the TN removal efficiency of the whole system was fitted with a nonlinear curve(R^(2)=0.7192).The TN removal load rate in the HSCWs was 2.7–3.7 times that in the SFCW.The SFCW,which had high-density plants(35 plants/m^(2)),increased the proportion of nitrogen removed by plant harvesting and microbial function.The TN transformed by Iris pseudacorus L.accounted for 54.53%in the SFCW.Furthermore,bacteria completed the nitrogen cycle in the SFCW through a variety of nitrogen removal pathways.This research not only investigated the TN removal performance in an MCWP system but also made it possible to predict the TN removal efficiency according to the daily highest temperature from summer to winter in the field.
基金Project(2006BAJ01A05) supported by National Science and Technology Pillar Program during the 11th Five-year Plan Period of China
文摘To explore the energy saving effect of building envelope, the experiments were carried out through a comparison of basic cubicle in summer. Experiments show that if energy efficiency measures are applied only in the external walls and windows, the energy saving cubicles have an average energy efficiency ratio of 27.75% and 27.05% when the air change rates are 1.1 and 1.4 h-1 in summer, with both values being over the standard target value by 25%. And the indoor air temperature of the energy saving cubicle is below that of the basic cubicle. The daily mean temperature difference between the interior surface of insulation wall and no insulation reaches 1.47℃, and the mean temperature difference is up to 8.52℃ between the interior surface and exterior surface of insulating glass and single glass. The two cubicles were simulated for energy consumption using VisualDOE4.0 software under real weather conditions in summer. The results show that the mean deviation is 10.02% between experimental and simulated energy efficiency ratio. The correctness and validity of simulation results of the VisualDOE4.0 software are proved.
基金supported by the National Basic Research Program of China(973 Program)(Grant No.2004CB719700)CAS Knowledge Innovation Program Important Direction Project(Grant No.KJCX2-SW·206)Hi-Tech Research and Development Program of China(863 program)(Grant No.2003AA514023).
文摘The effect of different extraction and purification conditions on the microbial protein obtained from solid-state fermentation(SSF)and the effect of periodical dynamic changes of air on protein have been studied.The mechanism of solid-state fermentation with periodical dynamic changes of air is also discussed.Compared with static solid-state fermentation,periodical dynamic changes of air afford a higher protein mass;from 1 g of the fermentation microbe,5.3 mg of the intracellular protein(an increase of 34.63%)and 9.09 mg of the extracellular protein(an increase of 17.8%)were obtained on the sixth day of fermentation.The filter paper activity and carboxymethyl cellulose activity(FPA and CMCase)of the extracellular protein are 1.739μmol/s and 109.592μmol/s,respectively,which represent increases of 60.1%and 21.2%over the corresponding values for static solid-state fermentation.The FPA and CMCase of the intra-cellular protein are 0.245μmol/s and 6.392μmol/s,respec-tively,which represent decreases of 22.2%and 38.7%over the corresponding values for static solid-state fermentation.The enzyme activity of the microbial extracellular protein in solid-state fermentation with periodical dynamic changes of air on the fifth day is nearly equal to that on the sixth day without periodical dynamic changes of air,so the period of fermentation can be shortened.The sodium dodecyl sulfate-polyacrylamide gel electrophoresis(SDS-PAGE)experiments suggest that pulsating air pressure stimulation leads to a decrease in the amount of protein component with molecule mass of about 80400Da,and an increase in the amount of protein component with molecule mass of about 28520Da.
基金supported by Natural Sciences and Engineering Research Council of Canada(NSERC)-NSERC CREATE Mine of Knowledge,FRQNT(Fonds de recherche du Québec-Nature et Technologies),and Environment Canada
文摘Fossil fuel combustion and many industrial processes generate gaseous emissions that contain a number of toxic organic pollutants and carbon dioxide（CO_2） which contribute to climate change and atmospheric pollution.There is a need for green and sustainable solutions to remove air pollutants,as opposed to conventional techniques which can be expensive,consume additional energy and generate further waste.We developed a novel integrated bioreactor combined with recyclable iron oxide nano/micro-particle adsorption interfaces,to remove CO_2,and undesired organic air pollutants using natural particles,while generating oxygen.This semi-continuous bench-scale photo-bioreactor was shown to successfully clean up simulated emission streams of up to 45% CO_2 with a conversion rate of approximately 4%CO_2 per hour,generating a steady supply of oxygen（6 mmol/hr）,while nanoparticles effectively remove several undesired organic by-products.We also showed algal waste of the bioreactor can be used for mercury remediation.We estimated the potential CO_2 emissions that could be captured from our new method for three industrial cases in which,coal,oil and natural gas were used.With a 30% carbon capture system,the reduction of CO_2 was estimated to decrease by about 420,000,320,000 and 240,000 metric tonnes,respectively for a typical 500 MW power plant.The cost analysis we conducted showed potential to scale-up,and the entire system is recyclable and sustainable.We further discuss the implications of usage of this complete system,or as individual units,that could provide a hybrid option to existing industrial setups.
基金supported in part by the Department of Science and Technology,Ministry of Science and Technology,Government of India through the project-Community-Scale Energy Demand Reduction in India(CEDRI)under Grant DST/TMD/UK-BEE/2017/20.
文摘Many dwellings in warm-humid climates attain a comfortable environment by natural ventilation.The opening of exterior windows for ventilation allows the entry of insects along with the breeze.As a remedy,occupants install insect-proof screens on windows resulting in reduced airflow into the interior.This study attempts to evaluate the air change effectiveness and thermal comfort in a residential kitchen with insect-proof screens.A kitchen with insect-proof screens on the windows is compared with a case without insect-proof screens.Numerical simulation was conducted using ANSYS Fluent 2019 R2.The insect-proof screen is modelled as a porous media.The air velocity and temperature measurements were validated by measurements in a real scenario.The presence of insect-proof screens reduced the air velocity inside the space by 82%.However,the airflow pattern in the case with screens was more uniformly distributed.The mean age of the air was considerably higher in the case with insect-proof screens,which in turn resulted in a reduced ACE.The presence of an insect-proof screen resulted in a Predicted Mean Vote(PMV)of 2.79 indicating a‘hot’sensation,whereas in the other case,the comfort vote is only 1.93 indicating a‘warm’sensation.The presence of insect-proof screens on windows reduced the air velocity and ventilation efficiency,contributing to increased thermal discomfort in the kitchen.
基金supported by special fund of“Research and Demon-stration of Green and Low Carbon Design Methods and Key Tech-nologies for Hospitals and Biosafety Laboratories”by CABR(No.20220106330730007)supported by Youth Fund Project of“Research on Key technologies of Low carbon design in Arthropod Biosafety Laboratory”by China Academy of Building Research.
文摘The high-level biosafety laboratory is not only the basic support for infectious disease prevention and control,but also interrelated with key areas such as environmental security and social security,which has attracted increasing attention.A good indoor environment is the premise to ensure the smooth progress of the experiment and biological risk prevention and control.In order to better understand the indoor environment of high-level biosafety laboratories,19 high-level biosafety laboratories in China(with a total of 65 main rooms)were carefully selected as the test objects from December 2020 to December 2022.According to the test methods specified in the Chinese standard GB 50346,the air change,cleanliness,static pressure difference,temperature,relative humidity,and illumination were tested and analyzed.The results showed that all the measured parameters met the requirements of the Chinese standard GB 50346,and the bio-safety performance was completely satisfactory.However,individual parameters showed some overlarge values:the proportion of main rooms with cleanliness levels of 7 and 8 exceeding 50%of the lower limit for air changes was 54.5%and 69.8%,respectively;the proportion of main rooms in BSL-3-b1 laboratories with atmospheric pressure differentials exceeding 50%of the standard lower limit was 94.7%;and the atmospheric pressure differential in the main rooms of BSL-3-b2 laboratories reached a maximum of nearly-160 Pa.On the premise of ensuring the cleanliness and pressure gradient of the main room,it may be possible to reduce the air change.This study,for the first time,reveals the environmental parameters of various types and levels of biosafety laboratories,which can provide reference for the design and operation of such facilities.
基金supported by the Key Laboratory of Ecology and Energy Saving Study of Dense Habitat,Ministry of Education,Tongji University(Grant No.20220104)the National Natural Science Foundation of China(Grant Nos.52378026 and 42175095)the Shenzhen Science and Technology Program(No.20220809120650001).
文摘Previous research was limited to flat-façade buildings when evaluating the indoor and outdoor ventilation performance in a multi-story building.However,envelope features can provide the shading effect to induce the temperature difference between surfaces exposed to direct solar radiation and those without solar radiation.This temperature difference between surfaces can enhance the thermal buoyancy and change indoor and outdoor ventilation performance.We conducted scaled outdoor experiments to examine the impact of various envelope features on indoor and outdoor ventilation performance in multi-story buildings.Compared to the flat-façade multi-building,the average normalized horizontal airflow velocity of overhang,small wing wall,and large wing wall multi-buildings increased by 12.41%,10.56%,and 5.56%,respectively.Cross-ventilation is more susceptible to envelope features than single-sided ventilation in air change per hour(ACH).Specifically,the ACH values of cross-ventilation for large wing wall,small wing wall,and balcony multi-buildings decreased by 69.98%,25.79%,and 12.12%relative to the flat-façade building.For the same envelope feature building,the ACH values of single-sided ventilation on the windward side are better than those on the leeward side,particularly the building with small wing walls,with an improvement of 12.77%compared to flat-façade.This study contributes to advancing the understanding of urban ventilation,and provides a valid basis for designing envelope features in urban buildings.
文摘Nowadays,the application of renewable energies such as solar energy in the building sector has increased notably considering the adverse impacts of climate change on human life;hence many studies have focused on the application of photovoltaic panels in buildings.In the current study,a 3D computational fluid dynamics(CFD)model has been developed to evaluate the performance of a newly designed building-integrated photovoltaic(BIPV)system.Given the negative influence of overheating on the lifespan and performance of PV panels,their passive air cooling has been studied.Further,the potential of rooftop-mounted solar panels in passive ventilation of buildings by generating natural convective currents has been explored.The developed CFD model takes into consideration the effects of radiation,conduction,and buoyancy-driven natural convective currents generated by solar PV panels which are heated due to the exposure to solar radiation heat flux.The results suggest that applying a high surface emissivity for the part of the roof beneath the PV panels intensifies the natural convective currents which in turn provides better cooling for PV panels with higher cooling effects at higher solar heat fluxes.Up to a 34%increase in the convective mass flow rate and a 3 K decrease in the mean temperature of the panels were attained by modifying the emissivity of roof surface.Such a 3 K decrease in the operating temperature of the PV panels can enhance their efficiency and lifespan by about 1.56%and 21%,respectively.Based on the operating conditions and system characteristics,the BIPV system yielded an air change rate(ACH)in the range of 3-13 which was considered to be highly prevalent in providing the required passive ventilation for a wide range of applications.It was also observed that the flow dynamics inside the building were affected by both the amount of solar heat load incident on the solar panels and the emissivity of the roof surface behind the panels.
基金supported by the National Natural Science Foundation of China(52178092)the Basic Research Funds for the Central Government"Innovative Team of Zhejiang University"under contract number(2022FZZX01-09).
文摘Intensive care units(ICUs)are the high incidence sites of hospital-acquired infections,where impinging jet ventilation(IJV)shows great potential.Thermal stratification of IJV and its effect on contaminants distribution were systematically investigated in this study.By changing the setting of heat source or the air change rates,the main driving force of supply airflow can be transformed between thermal buoyancy and inertial force,which can be quantitatively described by the dimensionless buoyant jet length scale(l_(m)^(-)).For the investigated air change rates,namely 2 ACH to 12 ACH,l_(m)^(-)varies between 0.20 and 2.80.The thermal buoyancy plays a dominant role in the movement of the horizontally exhaled airflow by the infector under low air change rate,where the temperature gradient is up to 2.45℃/m.The flow center remains close to the breathing zone of the susceptible ahead,resulting into the highest exposure risk(6.6‰for 10-μm particles).With higher heat flux of four PC monitors(from 0 W to 125.85 W for each monitor),the temperature gradient in ICU rises from 0.22℃/m to 1.02℃/m;however,the average normalized concentration of gaseous contaminants in the occupied zone is reduced from 0.81 to 0.37,because their thermal plumes are also able to carry containments around them to the ceiling-level readily.As the air change rate was increased to 8 ACH(l_(m)^(-)=1.56),high momentum weakened the thermal stratification by reducing the temperature gradient to 0.37℃/m and exhaled flow readily rose above the breathing zone;the intake fraction of susceptible patient located in front of the infector for 10-μm particles reduces to 0.8‰.This study proved the potential application of IJV in ICUs and provides theoretical guidance for its appropriate design.
