●AIM:To investigate the underlying mechanism of dry environment(autumn dryness)affecting the lacrimal glands in rats.●METHODS:Twenty Sprague-Dawley rats were randomly divided into two groups.The rats were fed in spe...●AIM:To investigate the underlying mechanism of dry environment(autumn dryness)affecting the lacrimal glands in rats.●METHODS:Twenty Sprague-Dawley rats were randomly divided into two groups.The rats were fed in specific pathogen free environment as the control group(n=10),and the rats fed in dry environment as the dryness group(n=10).After 24d,lacrimal glands were collected from the rats.The tissues morphology was observed by hematoxylineosin(HE)staining.Tandem mass tags(TMT)quantitative proteomics analysis technology was used to screen the differential expressed proteins of lacrimal glands between the two groups,then bioinformatics analysis was performed.Further,the immunohistochemical(IHC)method was used to verify the target proteins.●RESULTS:In dryness group,the lacrimal glands lobule atrophied,the glandular cavities enlarged,the sparse nuclear distribution and scattered inflammatory infiltration between the acinus were observed.The proteomics exhibited that a total of 195 up-regulated and 236 downregulated differential expressed proteins screened from the lacrimal glands of rats.It was indicated that the biological processes(BP)of differential expressed proteins mainly included cell processes and single BP.The cellular compositions of differential expressed proteins mainly located in cells,organelles.The molecular functions of differential expressed proteins mainly included binding,catalytic activity.Moreover,the Kyoto Encyclopedia of Genes and Genomes(KEGG)pathway analysis showed that the differential expressed proteins mainly involved lysosome,complement and coagulation cascade,and ribosome pathway.The IHC result verified that the up-regulated expression proteins of Protein S100A9(S100A9),Annexin A1(Anxa1),and Clusterin(Clu)in lacrimal glands of rats in dryness group were higher than control group.●CONCLUSION:The up-regulated expression proteins of S100A9,Anxa1,and Clu may be the potential mechanisms of dry eye symptoms caused by dry environment.This study provides clues of dry environments causing eye-related diseases for further studies.展开更多
The Dunhuang–Golmud railway passes through different deserts in arid areas,especially drifting-sand desert and sandy-gravel Gobi.The near-surface wind environment and wind-sand transport process vary due to different...The Dunhuang–Golmud railway passes through different deserts in arid areas,especially drifting-sand desert and sandy-gravel Gobi.The near-surface wind environment and wind-sand transport process vary due to different external factors,such as topography,vegetation,and regional climate,resulting in evident spatial differences in surface erosion and deposition.Consequently,the measures for preventing wind-sand hazards will differ.However,the mechanism and control theory of sand damage remain poorly understood.In this study,we used meteorological observation,three-dimensional(3D)laser scanning,and grain-size analysis to compare and evaluate the spatial distribution of wind conditions,sand erosion and deposition patterns,and grain composition in the drifting-sand desert and sandy-gravel Gobi along the Dunhuang–Golmud railway in China.Results show that the annual mean wind speed,the frequency of sand-driving wind,and the drift potential of sandy-gravel Gobi are higher than those of drifting-sand desert,indicating a greater wind strength in the sandy-gravel Gobi,which exhibits spatial heterogeneity in wind conditions.The major sediment components in sandy-gravel Gobi are very fine sand,fine sand,and medium sand,and that in drifting-sand desert are very fine sand and fine sand.We found that the sediment in the sandy-gravel Gobi is coarser than that in the drifting-sand desert based on mean grain size and sediment component.The spatial distributions of sand erosion and deposition in the sandy-gravel Gobi and drifting-sand desert are consistent,with sand deposition mainly on the west side of the railway and sand erosion on the east side of the railway.The area of sand deposition in the drifting-sand desert accounts for 75.83%of the total area,with a mean deposition thickness of 0.032 m;while the area of sand deposition in the sandy-gravel Gobi accounts for 65.31%of the total area,with a mean deposition thickness of 0.028 m,indicating greater deposition amounts in the drifting-sand desert due to the presence of more fine sediment components.However,the sand deposition is more concentrated with a greater thickness on the embankment and track in the sandy-gravel Gobi and is dispersed with a uniform thickness in the drifting-sand desert.The sand deposition on the track of the sandy-gravel Gobi mainly comes from the east side of the railway.The results of this study are helpful in developing the preventive measures and determining appropriate selection and layout measures for sand control.展开更多
The desert-oasis transition zone(DOTZ)serves as a buffer area between the desert and oasis.Understanding its wind field characteristics is of great significance for the prevention and control of aeolian disasters in t...The desert-oasis transition zone(DOTZ)serves as a buffer area between the desert and oasis.Understanding its wind field characteristics is of great significance for the prevention and control of aeolian disasters in the oasis.In this study,we used meteorological data during 2013–2019 from the portable meteorological stations at five sites(site A on the edge of the oasis,sites B,C,and D in the DOTZ,and site O in the desert)in Dunhuang,China to analyze the near-surface wind field characteristics and their causes,as well as to reveal the key role of the DOTZ in oasis protection.The results showed that the mean wind speed,frequency of sand-driving wind,and directional variability of wind decreased from west to east within the DOTZ,and wind speed was significantly affected by air temperature.The terrain influenced the prevailing winds in the region,mainly from northeast and southwest.Only some areas adjacent to the oasis were controlled by southeasterly wind.This indicated that the near-surface wind field characteristics of the DOTZ were caused by the combined effects of local terrain and surface hydrothermal difference.At site D,the annual drift potential(DP)was 24.95 vector units(VU),indicating a low wind energy environment,and the resultant drift direction(RDD)showed obvious seasonal differences.Additionally,the DOTZ played an important buffering role between the desert and oasis.Compared with the desert,the mean wind speed in the oasis decreased by 64.98%,and the prevailing wind direction was more concentrated.The results of this study will be useful in interpreting the aeolian activity of the DOTZ in Dunhuang.展开更多
Parkinson’s disease is the most common movement disorder,affecting about 1%of the population over the age of 60 years.Parkinson’s disease is characterized clinically by resting tremor,bradykinesia,rigidity and postu...Parkinson’s disease is the most common movement disorder,affecting about 1%of the population over the age of 60 years.Parkinson’s disease is characterized clinically by resting tremor,bradykinesia,rigidity and postural instability,as a result of the progressive loss of nigrostriatal dopaminergic neurons.In addition to this neuronal cell loss,Parkinson’s disease is characterized by the accumulation of intracellular protein aggregates,Lewy bodies and Lewy neurites,composed primarily of the proteinα-synuclein.Although it was first described almost 200 years ago,there are no disease-modifying drugs to treat patients with Parkinson’s disease.In addition to conventional therapies,non-pharmacological treatment strategies are under investigation in patients and animal models of neurodegenerative disorders.Among such strategies,environmental enrichment,comprising physical exercise,cognitive stimulus,and social interactions,has been assessed in preclinical models of Parkinson’s disease.Environmental enrichment can cause structural and functional changes in the brain and promote neurogenesis and dendritic growth by modifying gene expression,enhancing the expression of neurotrophic factors and modulating neurotransmission.In this review article,we focus on the current knowledge about the molecular mechanisms underlying environmental enrichment neuroprotection in Parkinson’s disease,highlighting its influence on the dopaminergic,cholinergic,glutamatergic and GABAergic systems,as well as the involvement of neurotrophic factors.We describe experimental pre-clinical data showing how environmental enrichment can act as a modulator in a neurochemical and behavioral context in different animal models of Parkinson’s disease,highlighting the potential of environmental enrichment as an additional strategy in the management and prevention of this complex disease.展开更多
Disturbance in wind regime and sand erosion deposition balance may lead to burial and eventual vanishing of a site.This study conducted 3D computational fluid dynamics(CFD)simulations to evaluate the effect of a propo...Disturbance in wind regime and sand erosion deposition balance may lead to burial and eventual vanishing of a site.This study conducted 3D computational fluid dynamics(CFD)simulations to evaluate the effect of a proposed city design on the wind environment of the Crescent Spring,a downwind natural heritage site located in Dunhuang,Northwestern China.Satellite terrain data from the Advanced Spaceborne Thermal Emission and Reflection Radiometer(ASTER)Digital Elevation Model(DEM)were used to construct the solid surface model.Steady-state Reynolds Averaged Navier-Stokes equations(RANS)with shear stress transport(SST)k-ωturbulence model were then applied to solve the flow field problems.Land-use changes were modeled implicitly by dividing the underlying surface into different areas and by applying corresponding aerodynamic roughness lengths.Simulations were performed by using cases with different city areas and building heights.Results show that the selected model could capture the surface roughness changes and could adjust wind profile over a large area.Wind profiles varied over the greenfield to the north and over the Gobi land to the east of the spring.Therefore,different wind speed reduction effects were observed from various city construction scenarios.The current city design would lead to about 2 m/s of wind speed reduction at the downwind city edge and about 1 m/s of wind speed reduction at the north of the spring at 35-m height.Reducing the city height in the north greenfield area could efficiently eliminate the negative effects of wind spee.By contrast,restricting the city area worked better in the eastern Gobi area compared with other parts of the study area.Wind speed reduction in areas near the spring could be limited to 0.1 m/s by combining these two abatement strategies.The CFD method could be applied to simulate the wind environment affected by other land-use changes over a large terrain.展开更多
Vegetation has positive effects on improving wind environment in residential areas which is important to the residents' pedestrian comfort. In order to reflect the impact of landscape on wind environment,a wind ex...Vegetation has positive effects on improving wind environment in residential areas which is important to the residents' pedestrian comfort. In order to reflect the impact of landscape on wind environment,a wind experiment was carried out in a typical residential area in Tsinghua University. Meanwhile,numerical simulation with reasonable plant models under the experimental boundary condition was held. By comparison between the experiment data and results of the simulation,wind direction of points in narrow passage and velocity of points in the first row facing the coming wind are almost accurate in simulation,but other points share big error percentage. The reason lies in the disturbing of wind model and settings of plant model. Moreover,by classifying measurement points according to relations between plants location and directions of coming wind,quantitative effects of vegetation are shown through simulations with plants and without plants. Plants directly facing the coming wind have most obvious function on decreasing the wind velocity,thus providing feasible scheme for vegetation design.展开更多
The authors seek, through tests on simulated sand samples in a wind tunnel and analysis of minerals combination and trace elements, to discover the environmental implications of flying-up, falling-down and concentrati...The authors seek, through tests on simulated sand samples in a wind tunnel and analysis of minerals combination and trace elements, to discover the environmental implications of flying-up, falling-down and concentration variation as a function of natural wind speed and direction, distance of movement, range and extent of influence on the atmospheric environment, of micro-granular components on the ground surface in the Keerqin desert area in northwest Liaoning Province of China.展开更多
To improve the outdoor environment of rural settlement and reduce the energy consumption of rural houses in winterin cold areas,the seriously bad wind environment should been controlled and considered. This paper appl...To improve the outdoor environment of rural settlement and reduce the energy consumption of rural houses in winterin cold areas,the seriously bad wind environment should been controlled and considered. This paper applies the method of numerical simulation to simulate the wind environment of some typical arrangement of building and courtyard in winter,and concludes the optimal building and courtyard arrangement types and strategies. It aims to provide some technical supports for improving the wind environment of rural settlements in cold regions.展开更多
The wind environment around residential building groups is increasingly concerned,while the dwelling groups as the elementary unit of planning design,its quality of surrounding wind environment will directly affect pe...The wind environment around residential building groups is increasingly concerned,while the dwelling groups as the elementary unit of planning design,its quality of surrounding wind environment will directly affect people's life. This study based on the climatic conditions of severe cold regions,selects four dwellings groups with different openings scale and position as the research objects,and then simulates and analyzes the wind speed distribution characteristics of each pattern. Meanwhile,it extracts the wind speed values of one hundred points of each pattern and applies the coefficient of uniformity method to the ecological evaluation. It has been found that grouping pattern of buildings has a dramatic effect on the resulting airflow behavior. Configurations that contain a T-shaped central space with small opened side can effectively prevent and contain airflow in the site offer. The interactive influence between layout of dwelling groups and wind environment are explored,so as to provide basis for the planning design of dwelling groups.展开更多
Studying and analyzing the dynamic behavior of offshore wind turbines are of great importance to ensure the safety and improve the efficiency of such expensive equipments.In this work,a tapered beam model is proposed ...Studying and analyzing the dynamic behavior of offshore wind turbines are of great importance to ensure the safety and improve the efficiency of such expensive equipments.In this work,a tapered beam model is proposed to investigate the dynamic response of an offshore wind turbine tower on the monopile foundation assembled with rotating blades in the complex ocean environment.Several environment factors like wind,wave,current,and soil resistance are taken into account.The proposed model is ana-lytically solved with the Galerkin method.Based on the numerical results,the effects of various structure parameters including the taper angle,the height and thickness of the tower,the depth,and the diameter and the cement filler of the monopile on the funda-mental natural frequency of the wind turbine tower system are investigated in detail.It is found that the fundamental natural frequency decreases with the increase in the taper angle and the height and thickness of the tower,and increases with the increase in the diameter of the monopile.Moreover,filling cement into the monopile can effectively im-prove the fundamental natural frequency of the wind turbine tower system,but there is a critical value of the amount of cement maximizing the property of the monopile.This research may be helpful in the design and safety evaluation of offshore wind turbines.展开更多
In future planning of the city, it is very important to consider the proper intelligent integration of renewable energy sources into the built environment for developing smart cities. Analysis of the wind velocity pro...In future planning of the city, it is very important to consider the proper intelligent integration of renewable energy sources into the built environment for developing smart cities. Analysis of the wind velocity profile in the built environment is very important for finding out the energy content in the wind and also to analyze the performance of wind turbines in the built environment. In this study, building topologies of smart city are investigated for finding out the wind velocity profile and the wind turbine power output in the built environment. The wind velocity distribution across buildings is numerically simulated by using commercial CFD (Computational Fluid Dynamics) software CFD-ACE+. Wind turbine power output is estimated by using the power curve of real commercial wind turbine and wind velocity distribution simulated by CFD software. It has been observed that the wind is accelerated in the intervening space between the buildings irrespective of distance between the walls of adjacent buildings under the condition, which are investigated in this study. The wind is accelerated across buildings, and is reduced rapidly after blowing through buildings, and recovered gradually. Since the wind is accelerated in the intervening space between buildings and reduced in the area at the back of buildings, a wind turbine should be installed at the area at the back of the buildings and located on center between the buildings. In this work, it is observed that size dimensions and layout of the building are effective in realizing a smart city for utilizing renewable energy such as wind turbine in the built environment.展开更多
This study investigated the flow characteristics altered by Jang Bogo Antarctic Research Station using computational fluid dynamics(CFD) modeling. The topography and buildings around Jang Bogo Station were constructed...This study investigated the flow characteristics altered by Jang Bogo Antarctic Research Station using computational fluid dynamics(CFD) modeling. The topography and buildings around Jang Bogo Station were constructed with computeraided-design data in the CFD model domain. We simulated 16 cases with different inflow directions, and compared the flow characteristics with and without Jang Bogo Station for each inflow direction. The wind data recorded by the site’s automatic weather station(AWS) were used for comparison. Wind rose analysis showed that the wind speed and direction after the construction of Jang Bogo Station were quite different from those before construction. We also investigated how virtual wind fences would modify the flow patterns, changing the distance of the fence from the station as well as the porosity of the fence. For westerly inflows, when the AWS was downwind of Jang Bogo Station, the decrease in wind speed was maximized(-81% for west-northwesterly). The wind speed reduction was also greater as the distance of the fence was closer to Jang Bogo Station. With the same distance, the fence with medium porosity(25%–33%) maximized the wind speed reduction.These results suggest that the location and material of the wind fence should be selected carefully, or AWS data should be interpreted cautiously, for particular prevailing wind directions.展开更多
It is important to improve residential thermal comfort in the high dense cities,in which wind environment is crucial.Waterside buildings take an advantage of micro-hydrological-climate in summer that should be used to...It is important to improve residential thermal comfort in the high dense cities,in which wind environment is crucial.Waterside buildings take an advantage of micro-hydrological-climate in summer that should be used to enhance residential thermal comfort especially in the subtropical region.In order to propose design approaches according to the outdoor thermal comfort of the waterside residential,a case study of Shenzhen She Kou residential district has been made.It focused on various factors that could have influence on wind environment for improving thermal comfort.Using wind velocity ratio(ΔRi)criterion,factors of building development volume,building direction and layout pattern,open space arrangement etc.have been broadly explored using FLUENT simulation.To planning parameters,the Floor Area Ratio(FAR)is significantly influence wind environment,the smaller FAR is better.To the vertical layout of the buildings,multi-storey layout and multi-storey&sub high-rise mixed layout would provide better wind environment.To the horizontal layout,the determinant is better than the peripheral.Other factors such as the buildings’direction towards the road,buildings’height,and open space setting,have influence on wind environment yet.In general,the more benefit of design layout for wind breezing,the better wind environment it could get.展开更多
A computational model has been developed for the simulation of pedestrian level wind environment around tall buildings by coupling the numerical simulation of the full scale site and meteorological station materials...A computational model has been developed for the simulation of pedestrian level wind environment around tall buildings by coupling the numerical simulation of the full scale site and meteorological station materials. In the first step, the hybrid/mixed finite element method is employed to solve the two dimensional Navier Stokes equation for the flow field around tall buildings, in view of the influence of fluctuating wind, the flow field is revised with the effective wind velocity. The velocity ratio is defined in order to relate numerical wind velocity to oncoming reference wind velocity. In the second step, the frequency occurred discomfort wind velocity as a suitable criterion is calculated by use of the coupling between the numerical wind velocity and the wind velocity at the nearest meteorological station. The prediction accuracy of the wind environment simulation by use of the computation model will be discussed. Using the available wind data at the nearest meteorological station as well as the established criteria of wind discomfort, the frequency of wind discomfort can be predicted. A numerical example is given to illustrate the application of the proposed method.展开更多
It is very important to consider proper intelligent integration and locations of renewable energy sources into the built environment for developing smart cities. Wind speed distribution study in the built environment ...It is very important to consider proper intelligent integration and locations of renewable energy sources into the built environment for developing smart cities. Wind speed distribution study in the built environment is very essential for analyzing the wind turbine performance located in the built environment. In this work, the building layout like nozzle is proposed and the objective is to optimize the building layout for increasing electrical energy output of wind turbine, assumed to be installed in actual cities of Japan. The wind speed distribution across buildings is numerically simulated by using CFD-ACE+. Wind turbine power output is estimated using the power curve of a real commercial wind turbine and wind speed distribution is simulated using CFD software. The meteorological data of Fukushima city and Tsu city of Japan are utilized for evaluating the wind speed distribution profile across the building and for finding the electrical energy output from wind turbine. The proposed building models, which have the angle between two buildings like nozzle of 90°, 135° and 180°, can provide the wind acceleration at the back of buildings for the wind blowing from the main wind direction and the angle of 135°is optimum building layout. In the case of installing the proposed building model in Fukushima city and Tsu city, the wind energy output in winter season is higher while that in summer season is lower irrespective of the buildings’ angle. The interaction between the change in frequency distribution of wind speed and direction throughout the year and the location of open tip of building model decides the power generation characteristics of the proposed building model.展开更多
Computational fluid dynamics(CFD)has become the main method for the prediction of the properties of the external wind environment in cities and other urban contexts.A review is presented of the existing literature in ...Computational fluid dynamics(CFD)has become the main method for the prediction of the properties of the external wind environment in cities and other urban contexts.A review is presented of the existing literature in terms of boundary conditions,building models,computational domains,computational grids,and turbulence models.Some specific issues,such as the accuracy/computational cost ratio and the exploitation of existing empirical correlations,are also examined.展开更多
Wind environment simulation of a commercial district in Baise city of Guangxi Province, China, is carried out in the design phase. The results are analyzed and based on the evaluation standard for greening building of...Wind environment simulation of a commercial district in Baise city of Guangxi Province, China, is carried out in the design phase. The results are analyzed and based on the evaluation standard for greening building of China. The simulation method is discussed in detail, and some suggestions for wind environment optimization are put forward, which might be helpful for similar research.展开更多
According to the verification regulation of the Wind Direction and Wind Speed Sensor of Automatic Meteorological Station[JJG(meteorological)004-2011],relying on the wind tunnel laboratory of Hebei meteorological measu...According to the verification regulation of the Wind Direction and Wind Speed Sensor of Automatic Meteorological Station[JJG(meteorological)004-2011],relying on the wind tunnel laboratory of Hebei meteorological measurement station,EL15-1 A type of wind speed sensor in the automatic weather station was verified.The experimental data of sensor verification in different laboratory environments were obtained through data comparison.Using standard wind speed measurement formula,the influence of laboratory temperature,humidity and air pressure on verification results was analyzed quantitatively.The results showed that laboratory temperature had the greatest influence on the verification results of this type of sensor,while the humidity and air pressure had less influence.Therefore,it should be noted that the temperature change in the laboratory should not be too large in the process of verification,so as to improve the accuracy of the verification results.展开更多
In the context of epidemic prevention and control,villages are the weakest part of epidemic prevention and control.Traditional villages,as representatives of villages,are often far away from cities,and medical conditi...In the context of epidemic prevention and control,villages are the weakest part of epidemic prevention and control.Traditional villages,as representatives of villages,are often far away from cities,and medical conditions are relatively backward.Based on this background,epidemic prevention and control are particularly important.The quality of the environment is positively related to the spread of the virus.This article wanted to use CFD technology to simulate the wind environment of the traditional village street space,so as to propose measures to optimize the wind environment of the traditional village street space,and provide references for the future planning of village layout.展开更多
基金Supported by Regional Science Foundation Project of the National Natural Science Foundation of China(No.82060827,No.82260891)The Key Discipline of Universities in the“14th Five-Year Plan”Autonomous Region-Traditional Chinese Medicine at Xinjiang Medical University.
文摘●AIM:To investigate the underlying mechanism of dry environment(autumn dryness)affecting the lacrimal glands in rats.●METHODS:Twenty Sprague-Dawley rats were randomly divided into two groups.The rats were fed in specific pathogen free environment as the control group(n=10),and the rats fed in dry environment as the dryness group(n=10).After 24d,lacrimal glands were collected from the rats.The tissues morphology was observed by hematoxylineosin(HE)staining.Tandem mass tags(TMT)quantitative proteomics analysis technology was used to screen the differential expressed proteins of lacrimal glands between the two groups,then bioinformatics analysis was performed.Further,the immunohistochemical(IHC)method was used to verify the target proteins.●RESULTS:In dryness group,the lacrimal glands lobule atrophied,the glandular cavities enlarged,the sparse nuclear distribution and scattered inflammatory infiltration between the acinus were observed.The proteomics exhibited that a total of 195 up-regulated and 236 downregulated differential expressed proteins screened from the lacrimal glands of rats.It was indicated that the biological processes(BP)of differential expressed proteins mainly included cell processes and single BP.The cellular compositions of differential expressed proteins mainly located in cells,organelles.The molecular functions of differential expressed proteins mainly included binding,catalytic activity.Moreover,the Kyoto Encyclopedia of Genes and Genomes(KEGG)pathway analysis showed that the differential expressed proteins mainly involved lysosome,complement and coagulation cascade,and ribosome pathway.The IHC result verified that the up-regulated expression proteins of Protein S100A9(S100A9),Annexin A1(Anxa1),and Clusterin(Clu)in lacrimal glands of rats in dryness group were higher than control group.●CONCLUSION:The up-regulated expression proteins of S100A9,Anxa1,and Clu may be the potential mechanisms of dry eye symptoms caused by dry environment.This study provides clues of dry environments causing eye-related diseases for further studies.
基金This research was supported by the National Natural Science Foundation of China(42171083,41871016)the Natural Science Foundation of Gansu Province,China(22JR5RA066).
文摘The Dunhuang–Golmud railway passes through different deserts in arid areas,especially drifting-sand desert and sandy-gravel Gobi.The near-surface wind environment and wind-sand transport process vary due to different external factors,such as topography,vegetation,and regional climate,resulting in evident spatial differences in surface erosion and deposition.Consequently,the measures for preventing wind-sand hazards will differ.However,the mechanism and control theory of sand damage remain poorly understood.In this study,we used meteorological observation,three-dimensional(3D)laser scanning,and grain-size analysis to compare and evaluate the spatial distribution of wind conditions,sand erosion and deposition patterns,and grain composition in the drifting-sand desert and sandy-gravel Gobi along the Dunhuang–Golmud railway in China.Results show that the annual mean wind speed,the frequency of sand-driving wind,and the drift potential of sandy-gravel Gobi are higher than those of drifting-sand desert,indicating a greater wind strength in the sandy-gravel Gobi,which exhibits spatial heterogeneity in wind conditions.The major sediment components in sandy-gravel Gobi are very fine sand,fine sand,and medium sand,and that in drifting-sand desert are very fine sand and fine sand.We found that the sediment in the sandy-gravel Gobi is coarser than that in the drifting-sand desert based on mean grain size and sediment component.The spatial distributions of sand erosion and deposition in the sandy-gravel Gobi and drifting-sand desert are consistent,with sand deposition mainly on the west side of the railway and sand erosion on the east side of the railway.The area of sand deposition in the drifting-sand desert accounts for 75.83%of the total area,with a mean deposition thickness of 0.032 m;while the area of sand deposition in the sandy-gravel Gobi accounts for 65.31%of the total area,with a mean deposition thickness of 0.028 m,indicating greater deposition amounts in the drifting-sand desert due to the presence of more fine sediment components.However,the sand deposition is more concentrated with a greater thickness on the embankment and track in the sandy-gravel Gobi and is dispersed with a uniform thickness in the drifting-sand desert.The sand deposition on the track of the sandy-gravel Gobi mainly comes from the east side of the railway.The results of this study are helpful in developing the preventive measures and determining appropriate selection and layout measures for sand control.
基金the National Key Research and Development Program of China(2020YFA0608403)the National Natural Science Foundation of China(42171083)the Natural Science Foundation of Gansu Province,China(23JRRA601).
文摘The desert-oasis transition zone(DOTZ)serves as a buffer area between the desert and oasis.Understanding its wind field characteristics is of great significance for the prevention and control of aeolian disasters in the oasis.In this study,we used meteorological data during 2013–2019 from the portable meteorological stations at five sites(site A on the edge of the oasis,sites B,C,and D in the DOTZ,and site O in the desert)in Dunhuang,China to analyze the near-surface wind field characteristics and their causes,as well as to reveal the key role of the DOTZ in oasis protection.The results showed that the mean wind speed,frequency of sand-driving wind,and directional variability of wind decreased from west to east within the DOTZ,and wind speed was significantly affected by air temperature.The terrain influenced the prevailing winds in the region,mainly from northeast and southwest.Only some areas adjacent to the oasis were controlled by southeasterly wind.This indicated that the near-surface wind field characteristics of the DOTZ were caused by the combined effects of local terrain and surface hydrothermal difference.At site D,the annual drift potential(DP)was 24.95 vector units(VU),indicating a low wind energy environment,and the resultant drift direction(RDD)showed obvious seasonal differences.Additionally,the DOTZ played an important buffering role between the desert and oasis.Compared with the desert,the mean wind speed in the oasis decreased by 64.98%,and the prevailing wind direction was more concentrated.The results of this study will be useful in interpreting the aeolian activity of the DOTZ in Dunhuang.
文摘Parkinson’s disease is the most common movement disorder,affecting about 1%of the population over the age of 60 years.Parkinson’s disease is characterized clinically by resting tremor,bradykinesia,rigidity and postural instability,as a result of the progressive loss of nigrostriatal dopaminergic neurons.In addition to this neuronal cell loss,Parkinson’s disease is characterized by the accumulation of intracellular protein aggregates,Lewy bodies and Lewy neurites,composed primarily of the proteinα-synuclein.Although it was first described almost 200 years ago,there are no disease-modifying drugs to treat patients with Parkinson’s disease.In addition to conventional therapies,non-pharmacological treatment strategies are under investigation in patients and animal models of neurodegenerative disorders.Among such strategies,environmental enrichment,comprising physical exercise,cognitive stimulus,and social interactions,has been assessed in preclinical models of Parkinson’s disease.Environmental enrichment can cause structural and functional changes in the brain and promote neurogenesis and dendritic growth by modifying gene expression,enhancing the expression of neurotrophic factors and modulating neurotransmission.In this review article,we focus on the current knowledge about the molecular mechanisms underlying environmental enrichment neuroprotection in Parkinson’s disease,highlighting its influence on the dopaminergic,cholinergic,glutamatergic and GABAergic systems,as well as the involvement of neurotrophic factors.We describe experimental pre-clinical data showing how environmental enrichment can act as a modulator in a neurochemical and behavioral context in different animal models of Parkinson’s disease,highlighting the potential of environmental enrichment as an additional strategy in the management and prevention of this complex disease.
基金supported by the National Basic Research Program of China(2012CB026105)the National Natural Science Foundation of China(41201003,41071009)the China Postdoctoral Science Foundation(2012M52819)
文摘Disturbance in wind regime and sand erosion deposition balance may lead to burial and eventual vanishing of a site.This study conducted 3D computational fluid dynamics(CFD)simulations to evaluate the effect of a proposed city design on the wind environment of the Crescent Spring,a downwind natural heritage site located in Dunhuang,Northwestern China.Satellite terrain data from the Advanced Spaceborne Thermal Emission and Reflection Radiometer(ASTER)Digital Elevation Model(DEM)were used to construct the solid surface model.Steady-state Reynolds Averaged Navier-Stokes equations(RANS)with shear stress transport(SST)k-ωturbulence model were then applied to solve the flow field problems.Land-use changes were modeled implicitly by dividing the underlying surface into different areas and by applying corresponding aerodynamic roughness lengths.Simulations were performed by using cases with different city areas and building heights.Results show that the selected model could capture the surface roughness changes and could adjust wind profile over a large area.Wind profiles varied over the greenfield to the north and over the Gobi land to the east of the spring.Therefore,different wind speed reduction effects were observed from various city construction scenarios.The current city design would lead to about 2 m/s of wind speed reduction at the downwind city edge and about 1 m/s of wind speed reduction at the north of the spring at 35-m height.Reducing the city height in the north greenfield area could efficiently eliminate the negative effects of wind spee.By contrast,restricting the city area worked better in the eastern Gobi area compared with other parts of the study area.Wind speed reduction in areas near the spring could be limited to 0.1 m/s by combining these two abatement strategies.The CFD method could be applied to simulate the wind environment affected by other land-use changes over a large terrain.
基金Project(50878111) supported by the National Natural Science Foundation of ChinaProject(2006BAJ02A02) supported by the National Research Plan Project during the 11th Five-Year Plan Period
文摘Vegetation has positive effects on improving wind environment in residential areas which is important to the residents' pedestrian comfort. In order to reflect the impact of landscape on wind environment,a wind experiment was carried out in a typical residential area in Tsinghua University. Meanwhile,numerical simulation with reasonable plant models under the experimental boundary condition was held. By comparison between the experiment data and results of the simulation,wind direction of points in narrow passage and velocity of points in the first row facing the coming wind are almost accurate in simulation,but other points share big error percentage. The reason lies in the disturbing of wind model and settings of plant model. Moreover,by classifying measurement points according to relations between plants location and directions of coming wind,quantitative effects of vegetation are shown through simulations with plants and without plants. Plants directly facing the coming wind have most obvious function on decreasing the wind velocity,thus providing feasible scheme for vegetation design.
文摘The authors seek, through tests on simulated sand samples in a wind tunnel and analysis of minerals combination and trace elements, to discover the environmental implications of flying-up, falling-down and concentration variation as a function of natural wind speed and direction, distance of movement, range and extent of influence on the atmospheric environment, of micro-granular components on the ground surface in the Keerqin desert area in northwest Liaoning Province of China.
基金Sponsored bythe National Project of Scientific and Technical Supporting Programs Funded by Ministry of Science & Technology of China(Grant No.2013BAJ12B02)the Fundamental Research Funds for the Central Universities(Grant No.HIT.KISTP.201419)
文摘To improve the outdoor environment of rural settlement and reduce the energy consumption of rural houses in winterin cold areas,the seriously bad wind environment should been controlled and considered. This paper applies the method of numerical simulation to simulate the wind environment of some typical arrangement of building and courtyard in winter,and concludes the optimal building and courtyard arrangement types and strategies. It aims to provide some technical supports for improving the wind environment of rural settlements in cold regions.
基金Sponsored by the Specialized Research Fund for the Doctoral Program of Higher Education(Grant No.20122302110041)National Natural Science Foundation of China(Grant No.51378136)the Fundamental Research Funds for the Central Universities(Grant No.HIT.KISTP.201419)
文摘The wind environment around residential building groups is increasingly concerned,while the dwelling groups as the elementary unit of planning design,its quality of surrounding wind environment will directly affect people's life. This study based on the climatic conditions of severe cold regions,selects four dwellings groups with different openings scale and position as the research objects,and then simulates and analyzes the wind speed distribution characteristics of each pattern. Meanwhile,it extracts the wind speed values of one hundred points of each pattern and applies the coefficient of uniformity method to the ecological evaluation. It has been found that grouping pattern of buildings has a dramatic effect on the resulting airflow behavior. Configurations that contain a T-shaped central space with small opened side can effectively prevent and contain airflow in the site offer. The interactive influence between layout of dwelling groups and wind environment are explored,so as to provide basis for the planning design of dwelling groups.
基金Project supported by the National Natural Science Foundation of China(Nos.11872233,11727804,and 11472163)the National Key Basic Research Project of China(No.2014CB046203)the Innovation Program of Shanghai Municipal Education Commission(No.2017-01-07-00-09-E00019)。
文摘Studying and analyzing the dynamic behavior of offshore wind turbines are of great importance to ensure the safety and improve the efficiency of such expensive equipments.In this work,a tapered beam model is proposed to investigate the dynamic response of an offshore wind turbine tower on the monopile foundation assembled with rotating blades in the complex ocean environment.Several environment factors like wind,wave,current,and soil resistance are taken into account.The proposed model is ana-lytically solved with the Galerkin method.Based on the numerical results,the effects of various structure parameters including the taper angle,the height and thickness of the tower,the depth,and the diameter and the cement filler of the monopile on the funda-mental natural frequency of the wind turbine tower system are investigated in detail.It is found that the fundamental natural frequency decreases with the increase in the taper angle and the height and thickness of the tower,and increases with the increase in the diameter of the monopile.Moreover,filling cement into the monopile can effectively im-prove the fundamental natural frequency of the wind turbine tower system,but there is a critical value of the amount of cement maximizing the property of the monopile.This research may be helpful in the design and safety evaluation of offshore wind turbines.
文摘In future planning of the city, it is very important to consider the proper intelligent integration of renewable energy sources into the built environment for developing smart cities. Analysis of the wind velocity profile in the built environment is very important for finding out the energy content in the wind and also to analyze the performance of wind turbines in the built environment. In this study, building topologies of smart city are investigated for finding out the wind velocity profile and the wind turbine power output in the built environment. The wind velocity distribution across buildings is numerically simulated by using commercial CFD (Computational Fluid Dynamics) software CFD-ACE+. Wind turbine power output is estimated by using the power curve of real commercial wind turbine and wind velocity distribution simulated by CFD software. It has been observed that the wind is accelerated in the intervening space between the buildings irrespective of distance between the walls of adjacent buildings under the condition, which are investigated in this study. The wind is accelerated across buildings, and is reduced rapidly after blowing through buildings, and recovered gradually. Since the wind is accelerated in the intervening space between buildings and reduced in the area at the back of buildings, a wind turbine should be installed at the area at the back of the buildings and located on center between the buildings. In this work, it is observed that size dimensions and layout of the building are effective in realizing a smart city for utilizing renewable energy such as wind turbine in the built environment.
基金funded by a Korea Polar Research Institute project (PE16250)Hateak KWON is financially supported by PE17010 of Korea Polar Research Institute
文摘This study investigated the flow characteristics altered by Jang Bogo Antarctic Research Station using computational fluid dynamics(CFD) modeling. The topography and buildings around Jang Bogo Station were constructed with computeraided-design data in the CFD model domain. We simulated 16 cases with different inflow directions, and compared the flow characteristics with and without Jang Bogo Station for each inflow direction. The wind data recorded by the site’s automatic weather station(AWS) were used for comparison. Wind rose analysis showed that the wind speed and direction after the construction of Jang Bogo Station were quite different from those before construction. We also investigated how virtual wind fences would modify the flow patterns, changing the distance of the fence from the station as well as the porosity of the fence. For westerly inflows, when the AWS was downwind of Jang Bogo Station, the decrease in wind speed was maximized(-81% for west-northwesterly). The wind speed reduction was also greater as the distance of the fence was closer to Jang Bogo Station. With the same distance, the fence with medium porosity(25%–33%) maximized the wind speed reduction.These results suggest that the location and material of the wind fence should be selected carefully, or AWS data should be interpreted cautiously, for particular prevailing wind directions.
文摘It is important to improve residential thermal comfort in the high dense cities,in which wind environment is crucial.Waterside buildings take an advantage of micro-hydrological-climate in summer that should be used to enhance residential thermal comfort especially in the subtropical region.In order to propose design approaches according to the outdoor thermal comfort of the waterside residential,a case study of Shenzhen She Kou residential district has been made.It focused on various factors that could have influence on wind environment for improving thermal comfort.Using wind velocity ratio(ΔRi)criterion,factors of building development volume,building direction and layout pattern,open space arrangement etc.have been broadly explored using FLUENT simulation.To planning parameters,the Floor Area Ratio(FAR)is significantly influence wind environment,the smaller FAR is better.To the vertical layout of the buildings,multi-storey layout and multi-storey&sub high-rise mixed layout would provide better wind environment.To the horizontal layout,the determinant is better than the peripheral.Other factors such as the buildings’direction towards the road,buildings’height,and open space setting,have influence on wind environment yet.In general,the more benefit of design layout for wind breezing,the better wind environment it could get.
文摘A computational model has been developed for the simulation of pedestrian level wind environment around tall buildings by coupling the numerical simulation of the full scale site and meteorological station materials. In the first step, the hybrid/mixed finite element method is employed to solve the two dimensional Navier Stokes equation for the flow field around tall buildings, in view of the influence of fluctuating wind, the flow field is revised with the effective wind velocity. The velocity ratio is defined in order to relate numerical wind velocity to oncoming reference wind velocity. In the second step, the frequency occurred discomfort wind velocity as a suitable criterion is calculated by use of the coupling between the numerical wind velocity and the wind velocity at the nearest meteorological station. The prediction accuracy of the wind environment simulation by use of the computation model will be discussed. Using the available wind data at the nearest meteorological station as well as the established criteria of wind discomfort, the frequency of wind discomfort can be predicted. A numerical example is given to illustrate the application of the proposed method.
文摘It is very important to consider proper intelligent integration and locations of renewable energy sources into the built environment for developing smart cities. Wind speed distribution study in the built environment is very essential for analyzing the wind turbine performance located in the built environment. In this work, the building layout like nozzle is proposed and the objective is to optimize the building layout for increasing electrical energy output of wind turbine, assumed to be installed in actual cities of Japan. The wind speed distribution across buildings is numerically simulated by using CFD-ACE+. Wind turbine power output is estimated using the power curve of a real commercial wind turbine and wind speed distribution is simulated using CFD software. The meteorological data of Fukushima city and Tsu city of Japan are utilized for evaluating the wind speed distribution profile across the building and for finding the electrical energy output from wind turbine. The proposed building models, which have the angle between two buildings like nozzle of 90°, 135° and 180°, can provide the wind acceleration at the back of buildings for the wind blowing from the main wind direction and the angle of 135°is optimum building layout. In the case of installing the proposed building model in Fukushima city and Tsu city, the wind energy output in winter season is higher while that in summer season is lower irrespective of the buildings’ angle. The interaction between the change in frequency distribution of wind speed and direction throughout the year and the location of open tip of building model decides the power generation characteristics of the proposed building model.
基金This work was supported by the National Natural Science Foundation of China(No.51976139).
文摘Computational fluid dynamics(CFD)has become the main method for the prediction of the properties of the external wind environment in cities and other urban contexts.A review is presented of the existing literature in terms of boundary conditions,building models,computational domains,computational grids,and turbulence models.Some specific issues,such as the accuracy/computational cost ratio and the exploitation of existing empirical correlations,are also examined.
文摘Wind environment simulation of a commercial district in Baise city of Guangxi Province, China, is carried out in the design phase. The results are analyzed and based on the evaluation standard for greening building of China. The simulation method is discussed in detail, and some suggestions for wind environment optimization are put forward, which might be helpful for similar research.
文摘According to the verification regulation of the Wind Direction and Wind Speed Sensor of Automatic Meteorological Station[JJG(meteorological)004-2011],relying on the wind tunnel laboratory of Hebei meteorological measurement station,EL15-1 A type of wind speed sensor in the automatic weather station was verified.The experimental data of sensor verification in different laboratory environments were obtained through data comparison.Using standard wind speed measurement formula,the influence of laboratory temperature,humidity and air pressure on verification results was analyzed quantitatively.The results showed that laboratory temperature had the greatest influence on the verification results of this type of sensor,while the humidity and air pressure had less influence.Therefore,it should be noted that the temperature change in the laboratory should not be too large in the process of verification,so as to improve the accuracy of the verification results.
基金Sponsored by Sci-Tech Support Program of Hebei Provincial Department of Science and Technology(16236004D-9)Social Sciences Foundation of Hebei Province(HB15YS070)。
文摘In the context of epidemic prevention and control,villages are the weakest part of epidemic prevention and control.Traditional villages,as representatives of villages,are often far away from cities,and medical conditions are relatively backward.Based on this background,epidemic prevention and control are particularly important.The quality of the environment is positively related to the spread of the virus.This article wanted to use CFD technology to simulate the wind environment of the traditional village street space,so as to propose measures to optimize the wind environment of the traditional village street space,and provide references for the future planning of village layout.