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Research progress and trend analysis of volatile organic compounds in China
ZHANG Gang-feng;BU Meng-ya;LI Jie;Shanghai Academy of Environmental Sciences;The article adopts the word frequency analysis and co-word analysis in bibliometrics, visualizes and renders the analysis results by VOSviewer software, and combined with the macro policy dynamics in the relevant domestic fields, a comprehensive analysis of the overall progress and trends of research in the field of VOCs in China, different stages of research hotspots, as well as the research heat of different treatment technologies. The results show that:(1)Since the beginning of the domestic exploration of VOCs management in the 1980s, the overall research on VOCs in China showed a significant upward trend;(2) The history of domestic VOCs research can be divided into four stages: the nascent period(1981-1990), the initial period(1991-2000), the growth period(2001-2010) and the active period(2011-present). The emergence of the active period is closely related to the macro policy dynamics in China, and the continuous introduction of control policies at the national level promoted the rapid rise of domestic VOCs research;(3) The “12th Five-Year Plan” is a clear watershed for domestic VOCs research, mainly focusing on indoor air pollution and basic treatment technologies such as adsorption and biological methods in the early stage, while after the “12th Five-Year Plan”, research focuses on industrial source pollution control and macro management policy decisions;(4) From the research trend of different VOCs treatment technologies, the research related to adsorption and catalytic oxidation is the earliest and still high in recent years, while thermal combustion is more concerned in practical application, but the research is relatively low;(5) Treatment technology is the main axis of VOCs research throughout China, and it is expected that in the future, domestic VOCs research will continue to focus on the application of relevant emission reduction technology research and development, O3 pollution control policy decisions, and synergistic emission reduction of VOCs and greenhouse gases, etc.
RESEARCH AND ADVANCE IN WASTEWATER TREATMENT BY FLOTATION
WEI Zai shan, XU Xiao jun, NING Ping & XU Jin qiu (College of Environmental and Engineering, Kunming University of Science and Technology, Kunming 650093, China)In the present paper, research, theory, equipment, application and prospect of flotation technique in wastewater treatment are summarized. Flotation method is a high speed and efficient technique in separation of solid and liquid. Flotation technique is paid close attention to by domestic and abroad scholars in the field of wastewater treatment. The techniques have been developed quickly since 1970, being used comprehensively in treating house sewage of urban, all kinds of industrial wastewater, as well as water supply, especially in purifying water of low temperature, low turbidity and rich algae. Flotation technigue not only substitute for sedimentation, but also serve as treatment of wastewater in advance, as well as contraction sludge. Compared with sedimentation, flotation technique has many advantages such as: (1) small occupying equipment, economical investment of capital construction; (2) good treatment efficiency, it treats plankton of low turbidity, rich algae water and original water that removed difficultly by sedimentation; (3) more economical in coagulant quantity than that of sedimentation; (4) reclaiming useful materials. There are many kinds of flotation, such as eletroflotation, disperse air flotation, dissolve air flotation according to ways of producing tiny air bubble. Industrial equipment of high efficient flotation includes flotation column, flotation pool and flotation machine. After treatment of wastewater containing oil and emulsion by flotation technique, total removal efficiency of COD cr and oil are 80%~99.5% and 70%~99.9% respectively, and every index is up to effluent standard. Also flotation can treats wastewater from a paper mill, reclaiming useful materials such as pulp fiber and packing materials, and the removal efficiency of BOD 5, COD cr , SS, TP are all 80%~90%. It is well known that it not only treats electrolytic cobalt wastewater and wastewater containing heavy metal ions, ions dyeing liquid and wool scouring effluent, but also treats tannery wastewater and house sewage of urban better, removes trihalomethane precursors from eutrophic water.
Comparative study on speciation of Cu,Pb and Zn from mining tailings via Tessier 5-step sequential extraction and improved BCR method
CHEN Li-wei;CHEN Hai-ying;WU Jun;CHAO Shu-lin;WEI Qi;The given paper has done a comparative study of the 3 fresh tailings collected from the tailing reservoir at Huogeqi Copper Mine,Inner Mongolia. In the paper,the author has made a comparative study of the special features of Cu,Pb,and Zn in the tailing samples with the Tessier sequential extraction method and the modified BCR method,respectively. The results of our study show that Cu is mainly existing in the binding organic form as well as in the residual form whereas Pb and Zn are mainly existing in the oxidizable and exchangeable form through the Tessier sequential extraction way. But most of Cu in the tailing samples exists in the deoxidized form with most of the Pb content existing in its residual form. As to most of the Zn content,it exists in its residual and acid extractable form through the BCR modification. In comparison with the Tessier sequential extraction method,the modified BCR method is usually referred to as the exchangeable form and carbonate binding form as the acid extractable form,whereas the deoxidized form can be taken as a reduced one. Thus,all in all,there should be said existing 4 specialized forms. Since the content rate of the available heavy metal forms extracted by using the Tessier method can be higher than that by the improved BCR method,the order of the heavy metal migration capacity obtained by Tessier method can be illustrated in an order of Zn,Cu,Pb. And,in comparison,the descending order that can be obtained by the improved BCR method stands as Cu,Zn,Pb. The recovery rate of the existing form extracted by the improved BCR method can be achieved to the range from90% to 97%,though the recovery of the Tessier method tends to vary greatly from 29% to 485%. The ratio between the residue form and the effective form indicates that the migration capacity of Cu and Pb that can be obtained by using the Tessier method proves weaker,though that of Zn seems a bit stronger. And,though the modified BCR method is more suitable for the analysis of speciation of heavy metals in tailings,the Tessier sequential extraction method only shows a poor recovery rate. Thus,it can be seen that,the 2 methods can usually be adopted to analyze the specific and characteristic features of the heavy metals in the soils. As far as the heavy metals in the said metallic tailings,they should be attributed to the different results. Therefore,it suggests that the different research objectives should be taken to choose their particularly available corresponding analysis methods and the actual situations of the samples used when analyzing the specific features of the heavy metals in tailings. Thus,it can be seen that the above results we have arrived at can provide a theoretical as well as the practical basis for the research topic.
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.
Urban solid waste classification and transportation path optimization based on multi-vehicle and multi-journey
MU Neng-ye;CHENG Chi-yao;JIANG Er-wei;TIAN Pei-lin;The generation and disposal of urban waste are important sources of urban environmental pressure. In the waste collection and transportation network, the choice of routes can be greatly affected by the use of different transportation modes and vehicle models, resulting in different total costs of waste collection and transportation. This paper proposed a scheduling model of urban waste classification and transportation and analyzed it with cases based on the actual paths analyzed by ArcGIS. First of all, in light of the distribution of waste transfer facilities in Jinniu District of Chengdu, we used the spatial analysis function of ArcGIS to obtain the range and location information of waste collection points from the perspective of geographic space. Next, according to the characteristics of sorted urban waste, we configured various collect and transport equipment from different angles and converted the limitations in the actual problems into constraints. Then, we established a separate transportation model with multiple vehicles, multiple trips, and time windows, as well as a combined transportation model with multiple vehicles, multiple trips, and time windows. After that, based on the distribution of transfer facilities, we used the information of acquired collection points and the real path distance matrix obtained by the OD analysis function to construct a calculation case, utilized the simulated annealing algorithm to solve the two types of transportation models afterward; after inputting the algorithm solution results into ArcGIS, we got the actual collection and transportation routes and further carried out sensitivity analysis of the number of vehicles and the proportion of warehouse capacity. The results showed that: for the mode of separate transportation, the use of multiple types of waste collection vehicles can effectively reduce the total cost of collection; and for the mode of combined transportation, if the compartment volume ratio is close to the waste classification, the loading rate of vehicles can be increased, thereby reducing the total number of vehicles and the total cost of mileage. Finally, a comprehensive analysis indicated that: for sorted urban waste, the mode of combined transportation is more efficient than the mode of separate transportation, which can significantly cut down the total social cost and can also effectively reduce environmental pollution.
Application of risk assessment on fuzzy comprehensive evaluation method based on the cloud model
XU Zheng-jie;ZHANG You-peng;SU Hong-sheng;School of Automation and Electrical Engineering,Lanzhou Jiaotong University;The paper intends to introduce a comprehensive safety evaluation method based on the cloud model for evaluating the railway signal system. The reason and the need for us to pick up such a subject is that the existing evaluation methods fail to reflect the functions of the random nature of the risk factors in the riskprevention assessment area. Therefore,we think it necessary to put forward a fuzzy comprehensive evaluation method based on the cloud model to assess the risk of the temporary speed limit function for the train control center. In proceeding with our research, first of all,we have set up an assessment system based on the cloud model theory including the factor setting,the weighing factors setting and that of the evaluation criteria. Secondly,we have worked out a comprehensive evaluation matrix and weighing matrix of the conventional fuzzy comprehensive evaluation factors and the ways to transform them into the matrixes represented in numerical features via the backward cloud generator. What is more, we have also taken all the comprehensive evaluation matrix and weighing matrix based on the cloud model into comprehensive account so as to get the desirable comprehensive evaluation results. In addition,the evaluation process has also been included into the model so as to determine the relative degrees of the importance for evaluating the risk factors and the membership functions in the fuzzy way. And,finally,the group decisions as to the evaluation results can be gained by the synthetically aggregated cloud model when they were put into the forward cloud generator through proper calculation. Thus,what we would like to do is to make the cloud drop with the properties of the risk grades and the assessment results easy to be simulated by MATLAB when determining the final risk grades of the temporary speed limit function for the train control center. The practical assessment results show that the application of the cloud model in the reconstruction of the membership functions is favorable to realize the transition from the accurate data into the quality data by combining the fuzziness and randomness,so as to make the assessment results of the suggested methods visual and dependable,and increase the visual and virtual intuitiveness of the reference data and information of the risk assessment.
Application of TOPSIS method based on entropy weight evaluation of water resources carrying capacity in Changchun City
XU Zheng-hua;CAO Yan-ming;To evaluate the water resource carrying capacity of Changchun City, a regional water resources carrying capacity evaluation index system with four aspects including the water resources system, social system, economic system, and ecological environment system was established. The index system consists of 14 indicators such as environmental water use rate. TOPSIS model evaluation method with improved entropy weight is used, information entropy is used to calculate the weight of each evaluation index, and the optimal solution of Euclidean distance is used for water resources carrying capacity evaluation. The results show that: from the perspective of cities and counties, the water resource carrying capacity in descending order are Dehui City, Yushu City, Changchun City, Shuangyang District, Jiutai District, and the water resource carrying capacity is at the III “medium” level; Nong'an County is ranked last, and the carrying capacity of water resources is at the “weak” level of II. Water resources per unit area, proportion of surface water resources, per capita water resources, and urbanization rate indicators are favorable factors affecting the water resources carrying capacity of Changchun City. The remaining 10 indicators include per capita water resource utilization and irrigation water consumption per unit area are unfavorable factors. On the whole, this area has relative development and utilization potential. In a certain area and time, it can provide water resources for the economic and social development of Changchun City. However, the future development situation is not optimistic, and necessary attention and effective measures should be taken. The evaluation results are consistent with the actual conditions of water resources in each city(district) and county. The evaluation model can comprehensively consider influencing factors, effectively reduce the impact of subjective factors in the evaluation, and provide a theoretical basis and feasibility reference for the evaluation of water resources carrying capacity.
Research on calculation and influencing factors of carbon emission during the materialization phase of prefabricated buildings
LI Mengmeng;CHEN Weigong;LI Long;To further analyze carbon emission and its key influencing factors during the materialization phase of prefabricated buildings, this study firstly determined the system boundary of this phase, and then by using the carbon emission coefficient method, established a carbon emission calculation model for this phase. On the basis of quantified data, a structural equation model was used to analyze the carbon emission factors in this phase in an in-depth manner from the perspective of engineering management. Fourteen relationship hypotheses were proposed in six aspects: project overview, building materials consumption, transportation and storage, energy consumption, construction organization and management, and carbon emissions in the materialization phase of projects, purposed to fit and evaluate the influencing factors. Through case analyses, it is concluded that the carbon emissions in the production stage of construction materials are the highest in the whole materialization process according to the carbon emission calculation model for prefabricated building stages, accounting for 92.01% of the total emissions, followed by those in the construction stage(5.6%), building materials' transportation stage(1.46%), component transportation stage(0.63%), and component production stage(0.3%). As found in the structural equation analysis, the consumption of building materials delivers the strongest direct impact on carbon emissions in the materialization phase of projects; among the observation variables of building materials' consumption, the material selection gives the largest influence coefficient, i.e. 0.93, followed by the utilization rate of low-carbon materials(0.88) and the recycling and utilization of materials(0.83). The comprehensive impact of the project overview, construction organization, and management on carbon emissions in the materialization phase of projects are ranked in the top two, followed by building materials' consumption, transportation and storage, and energy consumption. Reduction of carbon emissions should be started from the initial stage of projects, with a focus on control over the production stage of building materials; meanwhile, it is necessary to optimize the scheme design and adopt new processes, new technologies, and other measures, so as to reduce carbon emissions. The results of this study provide some theoretical references for the formulation of low-carbon strategies.
An revised optimized model for urgent human evacuation based on graph theory and queuing theory
XIONG Li-chun;YANG Li-bing;CHEN Jian-hong;ZHENG Hai-li;SHI Dong-ping;School of Resource and Safety Engineering,Central South University;The 48th Research Institute of China Electronics Technology Group Corporation;Jingzhou Municipal Bureau of Tobacco Monopoly;The paper is inclined to introduce our optimized simulation model for a renovated optimized model for urgent human evacuation based on the graph theory and queuing theory.It is known that the urgent human evacuation model should be founded on the basis of shortening the human response and reaction time and evacuation executing time,particularly in the case of fire accidents or earthquake urgencies in the large office buildings or high-rise.The simulation model of ours has been developed with its focus put on the study of the optimized project for the human resource evacuation executing time.To solve the problem,the key point is to realize whether the people,say,the office workers,the staff-members of a company or an enterprise,can be safely made to escape from the fire or an earthquake disaster spots does mainly rely on the following two factors:the safety egress time needed and the actually available safety egress time.By the safety egress time needed we mean the time for the human beings to successfully escape from the disaster spots,whereas the available safety egress time means the time or chance that there may exist for the people to get escaped from the disaster.If there exists enough time likely to be used for all the people in the building to get out,the fire or other disaster safety design of this building can be said successful.It is necessary to mention that the basic research of evacuation is actually the study of the various parameters in the process of the evacuation.Such parameters may include the efficiency,the crowd density,the speed of the movement of the people,etc.The evacuation executive time includes the movement evacuation time and the lag time.The time of the evacuation movement includes the floor executive time and stairs executive time.This part of time may not be supposed to have blockades or the blockades were to be very little.It also means to say that the escapers can still keep a certain speed to steer.But the lag time may be very long,because the case of waiting in line may appear due to the limited outlets.In such critical moments,the evacuation executive time may be closely relevant with the escape route choice,which can be optimized based on the graph theory.Practically speaking,the queuing theory should be carefully chosen to optimize the stagnant time.The evacuation optimization model can help to optimize the reasonable design projects for the evacuation lines and the rapid escaping routes so as to optimize and improve the emergency evacuation management level.
On the ship pollutant emission inventory in Shanghai port
FU Qing-yan,SHEN Yin,ZHANG Jian(Shanghai Environmental Monitoring Center,Shanghai 200030,China)The present paper attempts to introduce its study on the shipping pollutant emission inventory by taking Shanghai Port as a case sample.As is reported,Shanghai port succeeded in handling 29.07 million TEUs in 2010,thus ranking the world's busiest container-shipping champion in taking the place of Singaporean port.What is more,having accomplished a cargo shipment of 650 million tons in 2010,Shanghai port has been already honored as champion in this connection in the world for consecutive four years since 2006.Great as the advancement in vessel-shipment inventory may be,it is undeniable that,with the corresponding shipping emissions,which has in turn brought about tremendous environmental impact on the air and water,and even on the entire environment of the metropolis.And,consequently,it has become urgent to work out a reliable and up-to-date ship emission inventory and take immediate measures to limit and reduce the negative impact of shipping emission on the city.It is just for this urgent need that we have investigated the emission inventory of criteria pollutants and green house gases of vessels in the port based on the bottom-up driving mode in 2010.With a detailed survey made and activity analysis on the registration records,vessels types,tonnage distribution,driving modes,emission factors and fuel correction factors,we have worked out a total emission inventory of the vessels in and out Shanghai port by using the emission estimation methods.And,then,we have further divided the above said shipment emission into 9 types of vessels under 4 driving modes within the outer port and the inner river water-ways.Furthermore,we have achieved the spatial distribution of pollutants and green house gases based on the resolution of 1 km × 1 km grids to meet the demands of the numeric modeling,supported by the automatic identification system(AIS) in our paper.Thus,it can be followed that the total emissions of PM10,PM2.5,DPM,NOx,SOx,CO and HC by vessels were found to be equal to 4 600 ton,3 700 ton,4 400 ton,57.3 thousand ton,35.4 thousand ton,4 900 ton and 2 100 ton in 2010.The entire shipment was accounted to have produced green house gases with 2.885 5 million ton of CO2,100 ton of N2O and 40 ton of N2O.Comparing the total emission inventory in Shanghai,we have got to know that the share of the shipment contribution of the metropolis is equal to 12.0%,9.0% and 5.3% of the three key pollutants,including SO2,NOx and PM2.5.Of all the kinds of shipment,the ocean-going vessels are responsible for the total emission inventory with the shares of 12.0%,8.4% and 5.1%,respectively.