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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.
Analysis of the dormitory building fire risk based on the Pyrosim simulation
LONG Xin-feng;ZHANG Xue-qin;LOU Bo;School of Chemistry and Chemical Engineering,South China University of Technology;School of Electric Power,South China University of Technology;This paper is inclined to bring about an analysis of likely-to-be existing factors to cause the dormitory fire risks by taking No. 6 Dormitory of a certain university as a case study sample. In the paper,we have illustrated such factors of the building fire as the temperature,the smoke layer height,the heat flow,and the smoke movement in two different conditions with all the windows and doors being open,or with the windows closed but the doors opened 20 seconds later after the fire broke out. In doing so,we have also set up two conditions according to the two general situations of the students' dormitories( with the students living in at night for sleep and with them engaged in some daily activities). The results of the Pyrosim simulated research indicate that there doesn't seem to have any correlation or correlations be-tween the fire appearance and the two conditions mentioned above during the first 20 s since the fire broke out. And,later,when the doors and windows are opened,high temperature areas of the stairs would come into the room whereas the overall temperature in the dormitory remains lower and the smoke thickness begins to rise abruptly. Comparing the conditions with the windows closed and the door opened 20 s later,the high temperature area of the stairs would become spread over the upper space. Moreover,when the fire broke out,part of the violent heat may tend to propagate through the doors and windows. In such a situation,most of the heat would spread and propagate the high temperature of the fire to the firing room. Furthermore,with the aggravation of the fire disasters,the heat flow from the door and the accumulated heat flow in the firing room may turn to become much lower than that situation with the windows closed and the doors opened 20 s later. Thus,in the whole process,the upper stories of the fire building would be seriously suffered by the smoke in case the windows and doors of the firing room were opened. In contracts,the corridors and stairs would be more seriously affected by the smoke when the room windows in fire are closed with the door opened 20 seconds later.
Safety risk assessment for the railway gas tunnel construction based on the fuzzy-entropy method
WU Bo ;CHEN Hui-hao ;HUANG Wei ;The aim of this research is to assess the construction risk of the railway gas tunnels, whose construction has been on account of risks in a great variety. For instance, its construction involves lots of complicated influential factors in addition to the uncertainty and unexpected construction liabilities. It is just due to the above mentioned and lots of other unexpected reasons that the given paper intends to devote itself to make a detailed analysis in combination with a case project which involved lots of factors influencing the construction safety. And, then, based on the above said factors, we have managed to build up a safety risk assessment system for the railway gas tunnel construction procedures, with the quantitative range of gas tunnel construction risk assessment indexes carefully given. At the same time, we have also done a careful analysis of the assessment and scoring records for each factor of the safety risk assessment system of the said railway gas tunnel construction offered by the above said esteemed experts. Moreover, the weights of the factors at the various levels have also been reviewed and determined via the entropy method. Besides, the fuzzy mathematic model has also been taken to assess each factor bit-by-bit comprehensively, so as to gain the risk rating of the gas tunnel construction firmly. And, finally, we have managed to establish an assessment set to determine the risk rating spheres of the railway gas tunnel construction. The final conclusions have been made as follows:(1) The fuzzy entropy weight method is capable to solve the problem of the fuzzy assessment of the multiple influential factors through quantitative calculation, whereas the conclusive risk assessment of the railway gas tunnel project is definite, reasonable and qualified enough to guarantee the effective going on for the gas tunnel construction; And,(2), it is necessary for the successful construction safety to demand a strict and qualified supervision and control of key factors, such as the adjacent coal mines and the oil and gas fields, the lithological factors, the tunnel depth, the deadline limit of the coal mine tunnel construction into exploitation, the technical literacy of the operators, the geological exploitation factors and groundwater control, plus the coordination of other secondary affecting factors; And,(3) There exist potential risks of the railway gas tunnel construction accident, which has been assessed as level 3. And, so, the calculation results we have done prove to be in line with the actual project, with the similar projects taken for reference. And, therefore, the fuzzy-entropy method theory has been made adopted effectively and successfully to the risk assessment of the railway gas tunnel construction.
Analysis of thermal runaway temperature and gas production characteristics of lithium iron phosphate batteries with different states of charge
ZHU Yanli;XU Yibo;WANG Congjie;YANG Kai;ZHANG Mingjie;To better prevent and control explosion accidents in energy storage stations, it is necessary to conduct research on the thermal runaway process of energy storage batteries and to conduct an in-depth analysis of the produced gases and their components for potential safety hazards. This study conducted in-depth research on the thermal runaway process of energy storage batteries. Through 500 W heating tests on 60 Ah lithium iron phosphate batteries at different State of Charge(SOC), the study systematically analyzed the potential hazards of the produced gas components. FLACS software was used to study the hazardous nature of the gas components and, combined with the temperature-voltage-gas production curve evolution, summarized the thermal runaway process and gas production process of the battery. The research divided the thermal runaway process of the battery into three stages: thermal accumulation stage(Stage Ⅰ), thermal equilibrium stage(Stage Ⅱ), and thermal runaway and cooling stage(Stage Ⅲ). Besides, a thorough analysis of the gases produced by the battery was conducted, dividing the gas production process into four stages. It was found in the study that the thermal runaway of the battery triggers gas production, and the amount of gas production increases with the development of thermal runaway. Furthermore, FLACS software is used for explosion simulation, simulating the explosion behavior of premixed gases, and calculating the explosion limits of the gas components. The simulation and calculation results indicate that the variation in battery SOC has an impact on the combustion behavior of the combustible gases; the explosion limits and explosion overpressure of the mixed combustible gases increase with increasing in SOC. These research findings have important theoretical guidance significance for the safety protection of energy storage batteries and can provide a basis for the safety design of batteries, the formulation of emergency plans, and accident response.
Safety risk analysis of hoisting construction of prefabricated buildings based on Dynamic Bayesian Network
YANG Wenan;LI Jiaxin;To address the issues of multiple risk factors, high uncertainty, and dynamic changes in risk state during the construction of prefabricated building hoisting, a dynamic analysis method for safety risk during prefabricated building hoisting construction based on Dynamic Bayesian Networks is proposed. Firstly, according to the construction characteristics of prefabricated building hoisting and accident cause theory, 15 safety risk analysis indexes of hoisting are proposed from four aspects: human, material, environment, and management. The safety risk index system of hoisting construction of a prefabricated building is constructed. Then, the time dimension is introduced to establish a Dynamic Bayesian Network model, the probability of network nodes is quantified by fuzzy theory and expert scoring method, and the conditional probability is modified by combining the Leaky Noisy-or Gate extended model. Finally, the bidirectional inference function of the dynamic Bayesian network is used to analyze the dynamic risk of the safety risk of the hoisting of the prefabricated building. The time series change curve of safety risk in hoisting construction of a certain prefabricated building is obtained by case analysis, and the key risk factors leading to hoisting accidents are obtained by reverse reasoning. The results show that the probability of a lifting accident occurring at the initial moment is 0.313, and the probability of hoisting risk occurring increases significantly with the increase of construction time. Through the comparison of the posterior probability, it is found that the assembly building hoisting mainly has a greater risk in 2 aspects: human and material. The hoisting safety supervisory staff configuration, on-site construction safety management level, prefabricated components quality level, and lifting equipment operation condition are the key factors leading to the occurrence of hoisting construction safety risk. The research results can provide a new way to analyze and effectively control the safety risk of prefabricated building hoisting construction.
Methods for determing and estimating octanol-water partition coefficient of organic compounds
CHEN Hong--ping;LIU Yong--xin;LIANG Ying--hua Department of Chemical Engineering, Hebei University of Technology,Tangshan 063000, Hebei, ChinaEstimating and determining methods of octanol-water partition coefficient are reviewed and compared with each other. In this paper, the determining methods are introduced by means of classified as two classes-direct and indirect respectively. Direct methods consist of shake-flask method(including stir-flask method), two-phase titrations and extraction; Indirect methods are mainly introduced through generator column and chromatography. The limitation and specification of various of methods are picked out. In the introduction of estimation of partition coefficient, the methods are classified as two classes also. One is molecular method regarding the whole molecule as the studing object, such example as estimation partition coefficent by molecular volum; the other is structure and property method which look deeply into the structure and use the molecular structure as the studying target, such as Leo fragment, Meylan and Howard's atom/ fragment contribution method, three- level group contribution method, group contribution salvation mode, UNIFAC group contribution. The shortcoming and merit of these group contribution methods are primarily pointed out. Important topics of research work in this field are focused.
Construction and evaluation of community emergency response capacity index system in Yunnan Province
LIU Jie;HU Xin-yue;YANG Yi;WANG Wan-qing;DONG Chao;To solve the problem that the existing community emergency response capability evaluation index system is not uniform, the constituent elements are not clear, and the single evaluation method has ambiguity and randomness, this paper introduces a system engineering method—Hall with a three-dimensional structure as an analysis tool for the first time. From the three perspectives of the time dimension, logic dimension, and knowledge dimension, the model of community emergency response capability evaluation index system is constructed, and then a combination weighting-cloud model is selected as the evaluation method to evaluate the three communities. Firstly, this paper analyzes the relevant description information of community emergency response capability in national laws and regulations, industry standards, engineering practice, and previous literature, and preliminarily determines the alternative evaluation index set. Then, combined with 20 expert consultation opinions and 10 community research results, the index system of community emergency response capability is optimized, improved, and determined. Secondly, considering the accuracy of the weight coefficient, the correlation between the indexes, and the fuzzy randomness of the evaluation process, the entropy weight method and the G1 method are used to calculate the index weight, and the cloud model of community emergency capability evaluation is constructed. Finally, this model is applied to evaluate a certain urban community, a certain urban-rural integration community, and a certain rural community in Yunnan Province. To further verify the reliability and accuracy of the evaluation results of community emergency response capacity by this method, the analytic hierarchy process, fuzzy comprehensive evaluation method, Back Propagation(BP) neural network method, and grey clustering method are used to evaluate and compare these three communities. The results show that the index system can fully reflect the current situation of community emergency response capacity, and emergency management capacity. Emergency response capacity and emergency support capacity are important components. The constructed evaluation model can accurately evaluate the community emergency response capability, which can be further promoted and applied.
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.
Common factors leading to accidents and behavior type research based on prevention
FU Gui, LI Xuandong, LI Jun(School of Resources and Safety Engineering, China University of Mining & Technology-Beijing, Beijing 100083, China)This paper is focused on the study of the accidental common causes leading to accidents and the corresponding accident prevention strategy. At the very beginning of this paper, the authors introduces a few basic principles for safety science proposed by Heinrich and other safety scientists, (i.e.,) all the accidents have their own leading factors, which may be either the unsafe conditions or unsafe behaviors or the both. And the frequency of the accidents changes with its severity within an “accident triangle”. The first aim of this paper is to find all the common factors leading to the accidents. According to the basic principles, the author has categorized analytically and statistically all the factors discovered into 10 major classes as to the gas explosion accidents that have occurred in China's mines during 20002001. Then, we conclude that worker's unsafe working habits have been the main cause for the accidents. Then the authors examined a medical accident that was caused by spoiling children and a severe food poisoning involving 367 students, and the other two accidents caused due to the lack of safety knowledge and safety awareness. Based on the above statistics, the authors summarized all the common factors leading to the various accidents, which can be sequentially ordered as unsafe habit, lack of safety knowledge and safety awareness. Among the three, unsafe condition or unsafe behavior can be put together as one, with the other two being different by nature. As to the second aim of this paper, the author categorized a 3-level factor, that is, the safety management frame, the safety climate survey, and the behavior-based safety programs in the across-industry accident prevention map. And finally, the authors introduced some leading edge progress of the key elements in the prevention map in practical cases, such as Wilton-Olefines case and DuPont case for reader's information. The most important conclusion of this paper is that all the accidents share common factors. To fight against all the accidents, a common prevention strategy (map) can be developed with the key elements of the map developed and supplied by reference to that popularly used in some European and North American countries.
On the relation between carbon storage and reinforced fixation of the coastal wetland vegetation in the Yellow River delta area
ZHANG Xu-liang1,2,ZHANG Zhao-hui3,XU Zong-jun3,HOU Xue-jing4,CAI Qing-fang5(1 Shandong Provincial Key Laboratory of Eco-Environmental Science for Yellow River Delta,Binzhou University,Binzhou 256603,Shandong,China;2 Department of Geography,Qingdao University,Qingdao 266071,Shandong,China;3 The First Institute of Oceanography,State Oceanic Administration,Qingdao 266061,Shandong,China;4 School of Ocean Sciences,China University of Geosciences(Beijing),Beijing 10083,China;5 College of Marine Geosciences,Ocean University of China,Qingdao 266100,Shandong,China)The present paper is aimed at introducing our research of the relation between carbon storage and reinforced fixation of the coastal wetland vegetation in the Yellow River Delta Area based on our sampling surveys and some correlated statistical reference data.For our research purpose,we have surveyed the acreage of natural vegetations of the coastal wetlands and paddy fields in the Delta area and classified its natural vegetations into 3 sorts,that is,such as halarch vegetation,hydromorphic vegetation and hydrophilic vegetation.Our research has also measured the biomass and the net primary productivity of the natural vegetations and paddy fields,and worked out the carbon storage and carbon fixation per unit area and the total carbon storage and carbon fixation of the wetland vegetations.The results of our research show that the total carbon storage and carbon fixation of the wetland vegetations and paddy fields in the Delta area are equal to 200.54×104 t and 69.91×104 t/a,with its carbon fixation of the hydromorphic vegetations and paddy fields much higher than the mean carbon fixation of the global terrestrial vegetation(0.41 kg/(m2·a)) and the all-China terrestrial vegetations(0.49 kg/(m2·a)).However,the carbon fixation of the hydromorphic vegetations remains lower than that of the corresponding local latitudinal deciduous broad-leaved forest(1.06 kg/(m2·a)).As to its carbon fixation of the halarch vegetation and hydrophilic vegetation,the area remains lower than that of the global terrestrial vegetations or all-China terrestrial vegetations.Our survey shows that the carbon storage and carbon fixation of the vegetations of coastal wetland in the Yellow River Delta remains low,which is likely to reflect the fragility of the coastal wetland ecosystem of the area.All in all,the ever-increasing tendency of the area in reinforcing its natural vegetation and carbon storage and ever-intensifying fixation of the vegetations,in addition to the necessary countermeasures to protect the natural vegetations,are surely strengthened particularly in the reed association of coastal wetlands in the area.