被引排行
Effect of firecracker setting-off on the fine particle pollution in Beijing downtown areas
XU Jing 1,2,DING Guo-an1,YAN Peng1,ZHANG Jian-cheng3,WANG Shu-feng1,ZHANG Yang-mei1,MENG Zhao-yang1, LIU Yu-che1,ZHANG Xiao-ling2(1 Center for Atmosphere Watch and Services,Chinese Meteorological Administration,Beijing 10081,China;2 Institute of Urban Meteorology,Chinese Meteorological Administration,Beijing 100089,China;3 Nation Meteorological Center,Beijing 100081,China)The present article aims to report the authors' investigation of the effects of the firecrackers' setting off on fine particle pollution in Beijing's downtown areas during the Spring Festival period in 2003.Using TEOM(Tapered element oscillating microbalance)series 1400A instrument,the authors observed the data of mass concentration of PM2.5 and PM10.In doing the investigation,we have linked ACCU system to the bypass of TEOM instrument,with some filter aerosol samples collected.And then the chemical composition of PM2.5 was analyzed with the above mentioned method.The results of the above said investigation reveal that the firecrackers firing made the concentration of PM2.5 extremely high in a short moment with its actually hourly maximum mass concentration reaching 549 μg/m3 from our observed data.While the increasing speed of PM2.5 mass concentration went up as about 100 μg/m3 per-hour during the dense firecrackers time.In addition,when the mass concentration of PM10 was increasing,the value of PM2.5/PM10 would also increase simultaneously by getting to 0.9.Under the stable weather condition,high concentration of PM2.5 and PM10 may last 5-6 hours when the firecrackers were firing for longer time.In such a situation,the sedimentation of the particles whose diameter remained from 2.5 to10 μm may lead to the dropping of the concentration,though the percentage of PM2.5 in PM10 may keep high.Thus,the firecrackers made the concentration of the elements S,P,As,Al,Fe,Ti,Se,and K,the organic carbon,some soluble ions of PM2.5 higher.In conclusion,all the analogical compositions of fireworks,such as metallic powder,inorganic salt,sulfid and phosphide can be proved in correspondence with the actual pollution that occurred.
Influence of mesh grid and computational domain on FDS simulation
ZHU Shi,HUO Ran,HU Long-hua,YANG Dong(State Key Laboratory of Fire Science,University of Science and Technology of China,Hefei 230027,China)Seeing that FDS is a fire-spreading and smoke transport simulation software widely used in scientific research and engineering projects,this paper has done investigations on how to utilize the case of Steckler room fire test and made some quantitative studies over the mesh independency property by using the relative similarity analysis method.Further discussions have also been made with the sensitivity of the simulation results to the mesh grid in the fire source area,buoyancy plume area and smoke layer area,with the impact of the computational domain on the simulation result properly interpreted.The correlation value of the simulation results tends to increase while defining the mesh grid,and finally falls into the interval between 0.99 and 1.The impact of the mesh grid size on the correlation value of the simulation is likely to be most severe in the fire source area,less in the buoyancy plume area and the least in the smoke layer area.The correlation value of the results gained from the computational domain,the same in value with the Steckler room and that from the extended domain,tends to be relatively low,whereas that between the results in the domain extended to the distinctive size should be rather high.Thus,it can be concluded that the correlation analysis can be expected to become a reasonable method to assess the mesh grid independency.However,the sensitivity to the mesh grid size tends to drop from the combustion region to the smoke layer area,which suggests the grid size shrinking in the fire area is an effective way to gain more accuracy in an acceptable executive time.In addition,the choice of the computational domain may have an evident effect on the air flow-in and flow-out in the room, which is likely to further impact the temperature and velocity distribution in the building.Therefore,reasonable extension of the computational domain has been proved to be necessary to acquire accurate results.
SOME RESEARCH ON THE WAYS OF RED TIDE PREDICTION AND PREVENTION
MIAO Jin lai 1, 2 , SHI Hong qi 1, 2 , LI Guang you 2, WANG Bo 2 & HAN Li 2 (1 Marine Life College, Ocean University of Qingdao, Qingdao 266003, China) (2 Key Laboratory of Marine Bio active Substances, State Ocean Admission, Qingdao 26The present article aims at analyzing the actual situation of the ever increasing happening of the red tide along China's coast areas in recent years and the ways on how to predict their happenings timely. As is known, red tide is a serious global marine disaster causing billions of dollars' economic loss to the world and at least over 1 billion yuan loss to China. Furthermore, it has caused serious eco environmental problems to human existence. Based on our observation and research, this article has given a thorough analysis of the actual situation on the ever increasing outbreaks of red tides in recent years and has done a prediction of the trend of red tide happening this year. Our prediction is that the tide will come this year almost at the period as that of last year but a little sooner. The article has also summarized the current international methods for red tide prevention and brings the three detailed methods for prevention and controlling, that is, the physical method, chemical method as well as the biological one. The first method is to use hydroxyl radicals. Its mechanism is that hydroxyl radicals produced by the seawater and air under the action of electricity can totally kill the red tide cells and decompose the organic substances such as protein and polysaccharides in dead cells with no harm to fish. Second is large scale seaweed cultivation for nutrient removal to prevent red tide. Elevated nutrients are suggested to induce phytoplankton blooms, including "red tide" phenomenon. Some cultivated seaweed may be so productive as to absorb large quantities of N, P and CO 2 by producing large amounts of O 2 to reduce the eutrophication. The third method is to control the alga blossoming by producing bacteriological marine microbes. Such microbes play a decisive role in combating the occurrence of red tide based on their population variety and diversity, in addition to the diversity of their biophysiological and biochemical properties, their ecological function diversity and heredity diversity. The authors of this article believe and suggest that the bacteriological method is the best scientific way to manage and control the red tide occurrence.
Causation network analysis of the construction falling or collapsing accidents based on the text mining
LI Jue;WANG You-fang;The present paper has collected 558 reports in investigating the construction fall-from-height accidents that have occurred from 2012 to 2018 in China.In the paper,we have cherished our goal and inclinations to identify and clarify the root causes of such falling accidents in the construction due to the internal multiplicity of correlated factors among them as the research corpus in combination with the context exploration through social network analysis.On the basis of processing the corpus by R,we have carried out a text feature items dimension reduction through the method of χ2 statistics and displayed the results by a word cloud.According to the extracted 28 items and the co-occurrence computational matrix of such items,we have built up a co-occurrence network through a well-known Ucinet and Netdraw software in our paper.And,then,we have done the essentiality and the core-edge structure analysis to characterize the distribution features and the hierarchical structure of the network.And,finally,we have identified and determined the sets of the mutually related causes oriented on their strongly correlated causes to find the key ones.From the word cloud to be drawn,it can be clearly found that the entire distribution of the common construction falling accidents events,15 of them can be categorized as the core causes and 8 of them can be identified as the edge causes in the quoted reports.The analysis results of the above investigation can serve as indicative of the importance illustration of the cause item series to the network,signifying that poor safety awareness or inefficiency of the construction risk is the root cause that should be responsible for the above said accidents.A persuasive conclusion in the construction accidents is that the hazards involving such accidents can be accounted for and attributed to the poor safety awareness,misapplication of the protective equipment and facilities,inadequate inspection of the protective facilities,to the failure in timely inspection and rectification of the potential risk-leading equipment and installations,in addition to the operations against the needed rules or procedures.Therefore,in summery of our research insights from our corresponding comprehensive examination of the accidental causes,a strong and wholehearted concern and support for the safety of the construction builders should be provided to strengthen the construction workers' safety by the governmental authorities as well as the frontier construction company leaders.
Eco-environment security assessment study for the Binhai New Area,Tianjin,based on DPSIR model
SHAO Chao-feng,JU Mei-ting,ZHANG Yu-fen,LI Zhi(College of Environmental Science and Engineering,Nankai University,Tianjin 300071,China)This article is to present our study on the eco-environmental security assessment for the Binhai new area,Tianjin,based on DPSIR model.Analyzing the components of regional eco-environment security on the basis of historical research findings and the related literature,in accordance with the Driving Forces-Pressures-State-Impacts-Responses(DPSIR) model,we have laid out an indicator system of the eco-environmental security and assessment model for the area.To make our research more purposeful,first of all,we have selected 32 indicators to reflect the driving force,the social pressure,the state regulations,the impacts,the responses of the regional eco-environmental system.Such indicators as the level of industrialization,actual population density,annual GDP growth,resource wastage and waste released intensity of GDP,quality of the eco-environment(such as air,water,and the noise),biodiversity index,groundwater overdraft coefficient,the average life expectancy,recycling use of waste material,pollution control and management.Secondly,the weight of the indicators was confirmed by experts,and the national criteria,industrial standards with the investigation in developed regions both at home and abroad.As a result,all the indicators were divided into five levels.Last of all,we have proposed the integrated security assessment method,with the five grades of eco-environmental security status classified according to the eco-environmental security integrated index(E).The whole security assessment method for the Binhai New Area,Tianjin, placed on the basis of the detailed investigation on the current level of the local reality,and the systems analysis to the development planning and the future objects,was carried out.The results show that the E of Tianjin Binhai New Area in 2006 is 0.49,which proves that the eco-environmental security condition of the area is relatively unsafe.It was expected that in 2010 and 2020,the E will be expected to become 0.55(moderate condition) and 0.67(preferable condition), respectively.Moreover,we have also put forward some strategic measures for improving the eco-environment of the Binhai New Area,Tianjin,such as the centralized treatment of waste,energy saving and emission reduction.
Research on removing ammonia-nitrogen from water by activated zeolite
JIANG Zhe, NING Ping, PU Hong-ping, DENG Chun-ling, HUANG Xiao-feng (Department of Environmental Science and Engineering, Kunming University of Science and Technology, Kunming 650093, China)The present paper aims to introduce the authors' new ways on how to activate the natural zeolite and treat inorganic acid, inorganic salt, rare earth and the similar inorganic elements. First of all, the authors of the paper have given an account of the principles of the various activating methods. Then, comparing the testing results of ammonia nitrogen removal efficiency (or adsorption capacity), the paper presents the optimal method and the effect on the carrier caused by the chemical treatment, should be examined by means of X-ray diffraction. And finally, the kinetics of NH4~+ adsorption by activated zeolites and the refreshing experiments were investigated. The results of the present research show that all the above methods help to enhance the capacity of removing Ammonia-nitrogen from wastewater to a great extent. However, among these methods, the best one is the treatment with inorganic salt. The optimal process for manufacturing it should be based on the following conditions: the zeolite carrier should be soaked for 2 h in the 0.8 mol/L Na+ solution under 70~75 ℃. The total solid/liquor ratio is equal to 1∶50. Then, the carrier can be dried at 100 ℃ for 1h. In addition, it is also proved that the NH4~+ adsorption process is well described by modified Freundlich. As compared with the chemical coagulation and biological method, the absorption method is simpler, more efficient and profitable. Hence, it can be used as a new approach to further treatment of urban sewage waste.
Method on how to apply index of geoaccumulation to evaluate heavy metal pollution as result of inter-tidal sediments in Liaodong bay
ZHOU Xiu-yan, WANG En-de (Resources and Civil Engineering, Northeastern University, Shengyang 110004, China)This paper aims to discuss the influence of different geochemical backgrounds selected for assessing the metal pollution level in ocean floor sediments by using Igeo. As we know, Muller index of geo-accumulation or Igeo has been used as a widely recognized index for metal pollution indicating the contamination level found in sediments. To reduce such influence, it is suggested that the geochemical backgrounds selected be made in close relation to the sediment itself. In order to find the accurate content of Cd, Pb, Cu and Zn in the sediments of river mouths in Liaodong Bay, the author of this paper has made a very careful quantitative analysis on the samples gained from the field investigation, in which the geoaccumulation index was used to evaluate the heavy metal pollution in the sediments of the Inter-tidal in Liaodong Bay. The results of the author's analysis on the contamination degree of such heavy metals have shown that Cd was in high level while Pb, Cu and Zn stand in the middle. The results also showed that heavy metals pollution proves rather serious in the river mouths of Liaodong Bay. The exact pollution degrees in the following sites are respectively: the pollution in Wulihe River mouth in Huludao city is more serious than Dalinghe River mouth and Liaohe River mouth, with the latter being more serious than that of Shuangtaizihe River mouth, Yongninghe River mouth, Xiongyuehe River mouth, Liuguhe River mouth, Shihe River mouth and Zhimaowan in turn.
Statistical analysis and research on major and above coal mine accidents in China from 2011 to 2020
WANG Yungang;CUI Chunyang;ZHANG Feiyan;YAO Kang;KANG Junbao;To understand the causes and laws of large and above accidents in coal mines in China, the large and above accidents in coal mines in China from 2011 to 2020 were collected and sorted out. The number of occurrences, deaths, accident types and related laws of accident areas of large and above accidents in coal mines in China wasanalyzed. Then, the safety entropy model and safety degree were used to analyze the typical major coal mine accidents. The results show that:(1) The number of accidents and deaths in coal mines in China shows a decreasing trend, and the coal mine safety situation improved significantly;(2) In terms of accident types, the main factors for large and above accidents in coal mines are gas, water, roof, and fire. Among them, gas accidents occurred most, the most serious consequences, followed by flood accidents;(3) From the regional perspective, the provinces with a high frequency of coal mine accidents are Sichuan, Guizhou, Yunnan, Hunan, Shanxi, and Heilongjiang. The main reasons for this are the differences in coal seam occurrence conditions, coalfield geological structure, and underground environment in different regions of China;(4) The causes of coal mine accidents are that the safety degree of various influencing factors in the process of system production is declining, and the entropy value is increasing, which causes system confusion and leads to accidents. From the perspective of safety entropy model and safety degree, this paper analyzes the influencing factors of the extra-large gas explosion accident in Chifeng Baoma Coal Mine of Inner Mongolia and the extra-large accident in Songzao Coal Mine of Chongqing and puts forward effective prevention and control measures to make the system in a safe state, which can also provide reference and guidance for the safety production of coal mines.
Environmental impact of chromic slag and analysis of chromic slag’s output
DU Liang, WANG Jin-sheng (College of Environmental Sciences, Institute of Groundwater Safety & Environment, State Key Laboratory of Water Environmental Simulation, Beijing Normal University, Beijing 100875, China)To arouse the general public's awareness of the potential pollution of chromic slag to our living environment, the present paper has made a detailed review on the research results on the chromic toxicity by means of accumulating and analyzing the data concerned on chromate and calculating the discharge coefficient through such slag samples. As is known, chromic slag is a kind of chemical waste out of chromate production, whose dumping in the open air will cause waste water leach and pollute the surrounding soil and groundwater. As a result, the migrating chromium in the environment may give out an inhibiting action effect on the plants by keep them from absorbing other elements. As chromium has a strong induced mutation on the human chromosome, it will damage human's DNA. So far as we know, China has become one of the largest chromate producer, whose chromate production has already gone up by 160,000 tons. Its output and waste discharge coefficient is estimated to reach 350,000 tons to 420,000 tons. So large a lumber should be paid particular attention to by the departments concerned.
Evaluation model of loss of life due to dam breach in China
ZHOU Ke-fa, LI Lei, SHENG Jin-bao(Dam Safety and Management Department, Nanjing Hydraulic Research Institute, Nanjing 210029, China)This paper has brought forward a preliminary assessment model of casualty and material loss due to the dam breach and death data of the population at risk in accordance with the in-situ investigation results with the eight breached dams in China. We have also studied the similar cases and the returns of loss of life in reference to the dam breach abroad. In addition, the paper has also illustrated the main influential factors leading the dam breach, which determines the corresponding range of the values of the model parameters, and makes use of 19 scaling procedures by Saaty to gain the weighting coefficients of the influential factors. The new model and method given by Graham can both be applied to the actual estimation of casualty caused by the breach of the eight dams. The results of estimation gained have been carefully compared with the actual loss of life. Thus it can be found that the suggested model is better fit for the actual conditions in China. Furthermore, the suggested evaluation model has been checked with proper recommendations given for further improvement.