被引排行
THE BIOLOGICAL RESTORATION OF OIL-POLLUTED SOIL
REN Lei & HUANG Ting-lin (School of Environmental and Municipal Engineering, Xi'an University of Architecture & Technology, Xi'an 710055, China)The biological restoration techniques of oil-polluted soil is efficient,safe and easy to manage. Starting from the principle of biodegradation of oil-pollutant in soil, the new development of the technical measures and engineering methods, which enhance the effect of the biodegradation, is summarized in the present review. On this base, the direction of the progress of biological restoration technique is analyzed. The biological species that can degrade the oil-pollutant in soil are introduced in detail. The study shows that some new bacteria such as pseudomonas, bacterium, flavobacterium and micrococcus are segregated or incubated incessantly. The discussion of the biochemical principle of biodegradation of oil-pollutant in soil is given. It is considered that the study of the relationship between the degradation rate and the species of hydrocarbon is important. Hydrocarbons with branching structures generally reduce the biodegradation rate, and aromatic compounds are degraded more slowly than alkanes. The factors determining the rates of oil biodegradation in soil include the microbial community, temperature, humidity, pH value, oxygen, the quantity of nutrition and trace elements. All kinds of biological restoration techniques of oil-polluted soil are divided into two groups. One is ex-site technique, and the other is in-site technique. The land-farming,biopiles and composting constitute ex-site technique. The in-site techniques involve enhanced in-site biological restoration technique and vegetation-restoration technique. Many technical measures are developed to enhance the efficiency of biological restoration techniques of oil-polluted soil. It is noticed that using techniques such as favorable micro-organism, oxidant and surfactant are more and more popular. Finally, the trend of the biological restoration technique of oil-polluted soil is presented. There will be more and more new technology for use in this field. As biological restoration techniques become sophisticating, they will be used wider and wider. This is good for the protecting of ecological environment of the world.
On the identification of the safety helmet wearing manners for the construction company workers based on the deep learning theory
ZHANG Ming-yuan;CAO Zhi-ying;ZHAO Xue-feng;YANG Zhen;Department of Construction Management,Dalian University of Technology;School of Civil Engineering,Dalian University of Technology;This paper intends to propose an approach to the Faster RCNN with satisfactory accuracy,high speed with no need to add up any more auxiliary devices based on the Tensor Flow Framework to identify and check the safety helmet real time wearing manners for the construction workers. For the said purpose,we have collected over 6 000 photo-images of the construction workers in wearing their helmets and developed a diversified dataset of the photo-images by visiting different construction sites by ways of taking photographs and extracting frames from the surveillance videos. We have also pre-processed and filtered out the noise and scales of the photo-images simultaneously so as to get rid of the influence of noise making on the image detection and dissemination. What is more,the photo-images we have gained have also been turned to train and test the model by classifying them into two categories: the helmets the construction workers are wearing( safe) and those with no helmets( unsafe),which performance has also been registered and accounted based on the average precision and recalling. Thus,the statistical results indicate that the said rate for the workers' wearing safety helmets can be as precise as about 90. 91% and 89. 19%,correspondingly and respectively. The statistical results also show that the average precision and recalling rate identifying the workers' notwearing safety helmets has been done as precise as up to88. 32% and 85. 08%,respectively. Besides,in view of the undue irregularities of the workers' not wearing such helmets at construction sites,we have also extracted a few video streams from the surveillance camera at the entrance leading to the construction sites. Thus,the test experiment results demonstrate that the general precision and recalling rate for identifying the building workers' not wearing safety helmets prove to be as precise as up to 91. 44% and 89. 69%. In addition,the testing experiment and statistical results can also be done to verify the validity of the above mentioned method in the similar practical situations. Therefore,it can be concluded that,the application of the Faster RCNN method based on the deep learning to identify the workers' safety helmets can surely help to give out quick and prompt warning effect in changing such unsafe behaviors of the building workers at the construction sites and offer opportunities for necessary change so as to promote real-time site monitoring and heighten the safety management of the working order of the construction sites.
Pollution and risk evaluation of heavy metals in soil and agro-products from an area in the Taihu Lake region
LIU Hong-lian,LI Yan-hui,LI Lian-qing,JIN Liang, PAN Gen-xing(Institute of Resources,Ecosystem and Environment of Agriculture,Nanjing Agricultural University,Nanjing 210095,China)The present paper has done a detailed analysis to the samples collected from the soil and farm produce from a polluted farmland near a smelter in the Taihu Lake area with the respective contents of Pb,Cd,Hg,As,Cu,Zn,Ni,Cr and Se analysed in 2005.The pollution situation of the soil and farm produce has been assessed with the national background and guideline values of State Environmental Quality Category II,and by the values of the State Food Security Standard.And,finally,a general assessment of the exposure level by the food and drinking intake of the produce from the polluted and is given,while taking into account the R_fD values recommended by USEPA(2000).The results of the analysis indicate that the contents of the 8 metals both of the paddy and vegetable lands proved much higher than those stipulated in the National Background Standards in the area and the Nemeiro Indices detected indicated a heavy compound pollution of the multiple heavy metals,with Pb,Cd being most heavily polluted.Among the 9 metals of the samples,Pb and Cd were far above the State Food Guideline limits.Of all the farm produce,the metal contents of stem and leaf vegetables of crowndaisy,water spinach and cole reached the dangerous metal-content allowable levels.Thus,serious health risks are highly likely to get exposed to for the local people through their drinking and eating of the above-said farm produce,especially in case of potentially intense exposure to Cd,Pb and As.Therefore,serious concerns may arise as to the soil environmental pollution and health hazards due to the serious metal-pollutes soil in the Taihu Lake area.
Application of combination weighting and TOPSIS in the assessment of urban regional resilience under flood disaster
MENG Xiao-jing;CHEN Xin;CHEN Jia-jing;YANG Hong-gang;To quantitatively assess the ability of urban regions to cope with rainstorm flood disasters, the assessment index system of urban resilience under flood disasters was established based on resilient city ideas. 21 indicators were determined from the three attributes of resistance, adaptability, and recovery, as well as the four dimensions of economy, society, ecological environment, and infrastructure. Based on the principle of minimum relative information entropy, the combined weights of indicators were determined by the Analytic Hierarchy Process(AHP) and Criteria Importance Though Intercrieria Correlation(CRITIC). The assessment model of urban resilience was established using the Technique for Order Preference by Similarity to the Ideal Solution(TOPSIS). Taking Xi'an as an example, the resilience of resistance, adaptability, and recovery attributes and the resilience of economic, social, ecological environment and infrastructure dimensions were evaluated in six areas including Xincheng District, Beilin District, Lianhu District, Baqiao District, Weiyang District, and Yanta District. The level of urban regional resilience was obtained. The results show that the attribute of resistance and adaptability are the main factors that affect the level of urban resilience. The dimension of ecological environment and infrastructure have a greater influence on the urban resilience level, while the dimension of economy and society have little influence on the urban resilience level. The resilience levels varied greatly among regions. The levels of resilience of resistance, adaptability, and recovery attributes are highest in Baqiao District. The level of economic resilience is highest in Yanta District, and all dimensions of resilience are weak in Beilin District and Lianhu District. Moreover, the resilience rating of Baqiao District is Class III, the resilience rating of Xincheng District and Weiyang District is Class II, and the resilience rating of Beilin District, Lianhu District, and Yanta District is Class I. The assessment results provide a reference for improving urban resilience and reducing flood disaster risk.
APPLICATIONS OF MINERAL APATITES IN THE TREATMENT OF WASTE WATER
LIU Yu &PENG Ming-sheng (College of Earth and Environment Science, Zhongshan University, Guangzhou 510275, China)The present paper is concerned with the applications of minearal apaties A10[XO4]6Z2. Due to the particular crystal-chemical characteristics, mineral apatites including synthetic hydroxyapatite, fluorap-atite and natural mineral carbonate-fluorapatite can be used as excellent environmental function materials for treatment of heavy-metal and F- ions in waste water. The experimental results for aqueous Cd2+, Pb2+, Fe2+, [UO2]2+, Cu2+, Zn2+, Cr6+, Hg2+and F-show that apatites could remove effectively most of the heavy-metal ions from solution. Take the removal of Pb2+ by natural carbonate-fluorapatite as an example. Under the conditions of room-temperature, pH = 3 and action time of ca. 60 min,the attenuation ratio is 99. 4% and attenuated Pb2+ more than 1 100 mg per 1 g sample. Removal mechanisms include ad-sorption-sorption of cations on the apatites, surface-complexation, dissolution-precipitation and ion-exchange between the aqueous cations and the lattice Ca2+. The cations attenuated could be fixed into the lattice of apatite without re-dissolving that results in secondary pollution. The major factors affecting the attenuated effect include the types of phosphorite, mineral chemical composition of apatites, pH value in the solutions, conditioning time, initial concentration of aqueous heavy-metal ions, and the sample size and amount. In general, the hydroxyapatite shows a more active property than that of fluorapatite; siliceous phosphate is more effective than calciferous phosphate; the exist of structural carbonate could increase the specific area and the activity of sample. For different cations, the optimum pH value is different; increasing of action temperature would favour the removal rate but the balance time is generally 60-180 min.
On the 24 Model and the application of its causative codes to the analysis of the related accidents
FU Gui;WANG Xiu-ming;LI Ya;School of Resource and Safety Engineering,China University of Mining and Technology ( Beijing);The paper is aimed to introduce a so-called 24 Model and the application of its causative codes to the analysis of the actual accidents. As an important theoretical basis in the accident analysis and accident prevention,we have introduced an essential factor and its related operability in the aforementioned model to the applicability and the effect on the accident prevention. To enhance its operability in the accident analysis,we have made a further exploration of the relatively persistent and systematic accident causation model,that is,the 24 Model. For this purpose,we have first of all divided the accident causation factors of the24 Model within and outside the relative configuration,which cover all the four stages and two levels of the model. And then,in accordance with the above division,all the above mentioned accident causative factors in the model can be formulated and re-organized into a systematically programmed data-referential look-up table. And,eventually,we have managed to offer an analysis of a typical exemplary gas explosion accident to demonstrate how to use the said model. For example,the accident causations can be divided into 5 situational hierarchical categories,that is,the safety-less or mindless behavior caused accidents,the habitually behaved caused accidents; the accidents caused by the occupational or professional disease caused accidents; the accidents that have been caused by the mindless or poor sense of responsibility from the part of the management system; the accidents that have been caused by the poor safety management culture and external influential factors. Through the case investigative analysis,we have summed up and classified 21 accident causative events based on the definition of each module in the model,all of which can be brought into a code system of 24 Model. For example,a gas explosion accident has been resulted by a head of a coal mine who is in charge of the mining safety didn't pay enough attention to the rules for safety production and allowed an unprofessional worker to do blasting operations against the safety production regulations and safety production,which involves safety production culture in the gas explosion accident as has been mentioned above. And,what we have done in this paper is to disclose the potential riskinvolving codes of the accident causation factors in 24 Model,which help to improve the operability and actualities in the form of the aforementioned model, which can be easily and properly adopted as an effective tool in the mining safety related areas.
On criterion of social and environmental risk of reservoir dams
WANG Ren-zhong, LI Lei, SHENG Jin-bao(Dam Safety and Management Department, Nanjing Hydraulic Research Institute, Dame Safety Management Center of the Ministry of Water Resources, Nanjing 210029, China)The present research is about the evaluation criteria of the casualty, economic loss, impact of society and environment that the reservoir dams may bring about. As is known, the evaluation risk criterion on the impact of the society and environment is less discussed both at home and abroad. This paper has selected 8 important influencing factors, 4 of which are concerning the threat to the population, city importance, significant facilities, and cultural relics, historical sites, art collectors, rare and precious animals and plants and the other 4 of which are river configuration, animal and its habitat, natural and historical heritages, industrial pollution to the environment. The factors could be quantified by following the expert experience and then integrated into the social and environmental impact indices. An accordance with the Chinese situation, the paper presents a risk criterion of social and environmental preliminary reality by using FN curve as in the evaluation of human casualty in Australia. The primary application results in 6 Chinese reservoir dams show that the risk criterion and its integrated method are practical and reasonable on the whole and it can be applied in reservoir dam risk evaluation in the near future.
Study on construction risk factors based on ISM and MICMAC
LI Ming-zhu;WANG Wen-dong;ZHANG Zhi-chao;It is especially important to accurately identify the main factors that influence construction safety, analyze the working mechanism, and construct the system of influential factors in construction risk management. Firstly, this study screened out 14 main factors of construction risk and formed 6 levels of risk, like personnel factor, mechanical factor, environmental factor, management factor, and other factors based on analysis of direct and indirect causes of construction safety accidents. Secondly, this study also calculated the adjacency matrix and reachable matrix of construction safety risk factors and judged the relationship of the matrixes by use of MATLAB software. The study constructed an Interpretation Structure Model(ISM) and a hierarchical structure diagram to determine the hierarchical relationship among the influential factors and classified the influential factors according to the dependence and driving force using Matrix Impacts Cross-reference Multiplication Applied to a Classification(MICMAC). Finally, the study calculated a case using the established ISM model and MICMAC method to verify the feasibility of the application. The results show that the influential factors of the construction safety risk are divided into 6 levels(Li, i = 1-6) and the importance increases accordingly. Based on the dependence and driving force, the influential factors were divided into three categories: autonomous cluster, independent cluster, and dependent cluster. Human behavior and the safe state of facilities and equipment were at the level of L1 in the ISM model, with the low driving force and strong dependence, belonging to a dependent cluster. Management system, safety inspection, supervision, and management departments were at the level of L6 in the ISM model, with a potent driving force and low dependence, belonging to an independent cluster. It is concluded that human behavior and the safe state of facilities and equipment are important causes of construction safety risks. Management systems, safety inspection, supervision, and management departments are the most fundamental factors that constitute the risk of construction and need more attention. The model and method are feasible and effective to excavate risk factors, construction risk factor systems, analyze and determine the level, driving force, and dependence of risk factors, formulate corresponding risk management countermeasures and prevent and dissolve construction risks.
Route choice for transporting exigency succor materials
ZHANG Yi 1,2, GUO Xiao-fen1, WANG Xiao-feng1(1 School of Automobile, Chang'an University, Xi'an 710064, China;2 School of Vehicle & Motive Power Engineering, Henan University of Science & Technology, Luoyang 471003, Henan, China)This paper aims to introduce the authors' study of route choice for vehicles transporting exigency materials based on the Traveling Salesman theory as to the principles of timely, security and economy of the material dispatching under exigency situation. To describes the above three decision-making parameters in accordance with mathematics theory, it is necessary to establish their objective functions through processing the dimensionless technique and weight aggregation so as to set up a mathematical model for evaluating the utility of prepared route, and model merges collected information according to the expectation utility attributes as well as to make the multi-attribute decision-making problems into the single one. In order to find a scientific vehicle route and define a scheduling decision-making method for a dispatched person in an emergency rescue material transporting center and enhance the response effect of the emergency rescue, it is necessary to choose and establish the highest expectation utility plan. And, finally, an example has been presented in the paper for demonstrative analysis. The results indicate that there is a distinct difference between the objective decision of the transporting dispatch under emergency situation and the objective decision of enterprise transport dispatch under normal state. The former belongs to the shortest path problem of graph theory, but it can't be directly solved by the shortest path model and Dijkstra method, because there remains a problem for multiple decision-making objectives. Thus, the method based on the multiple attribute decision-making theory in evaluating the utility of the prepared routing proves effective for the person to schedule vehicle routing. But, its comparative superiority remains to be further explored and discussed.
Safety risk analysis for the deep foundation pit collapse accidents in the subway construction system
CHEN Shao-qing;XIONG Si-si;HE Chao-yuan;LAN Biao;To reduce and control the risk of deep foundation pit construction and avoid such pit collapse of deep foundation pit in the process of construction,the paper has taken a deep foundation pit excavation project of a subway station in Chongqing as a case study sample for the risk assessment. In doing so,it is first of all to analyze the likely causes of such collapse accidents on the construction spot to see such deep foundation pits in the said way. However,the general reasons for causing such collapse accidents can be summarized into 4 sorts: that is,the human factor,the construction technological factor,the environmental and management factors. On the above said bases,we have established a fault tree model of the deep foundation pit collapse accidents in terms of the engineering cases. And,secondly,such basic events are to be identified by the fault tree and then transform the basic likely events into the index layers in the analytic hierarchy process( AHP) so as to build up a hierarchical structure model through the above said fault tree model. Finally,a comparison has to be done by following the order of the structural importance of each basic event in the fault tree. The judgment and evaluation matrix in the analytic hierarchy process has been built up by calculating the weight value of each factor in the target whereas the disaster-causing factors of the foundation pit collapse accidents are to be qualitatively identified and quantitatively analyzed. Among the lots of basic causative events,the chief ones are to be the bedding slide of foundation pit slope,the influence of the surrounding buildings and the disturbance of the construction in the environmental factors. The unreasonable design of the supporting structure,the incorrect geological investigation data and the unreasonable construction organization planning can all be the 2-secondary essential factors,with the improper construction methods and irregular construction advances being the 3-rd level factors. Thus,the results of our study show that an improved and innovated analytic hierarchy process turns to be suitable and applicable for the purpose. And,the given results of the present study can help to lay a scientific basis for the safety management of the foundation pit construction in the subway construction enterprises.