Foamed cement fly ash is a new type of lightweight construction material that can be combined with a light steel frame to form light-steel skeleton–cement–fly ash foam wallboard (LSSCFAFW). The research on the axial compressive performance of light steel and light concrete composite wallboard is relatively limited. Four pieces of LSSCFAFWs were manufactured, and the impact of stand column quantity and various filler parameters on the LSSCFAFW was investigated. The failure mode of the wallboard and the influence of different parameter variables on its axial compressive performance were obtained through experiments. Moreover, the test results indicated essentially the same damage patterns in terms of stand-column buckling, filler crushing, and self-tapping screw failure. The addition of polypropylene fiber to this wallboard can prevent filler from falling off. The axial compressive performance of the LSSCFAFW demonstrates a direct proportion with the number of columns and cement content, improving as the number of stand columns and the cement content increase. However, the addition of polypropylene fiber to the filler has a minimal effect on the axial compressive performance of this wallboard. Compared to the control group, increasing the number of stand columns, adding 0.4% polypropylene fibers, and increasing the cement dosage to 50% improved the ultimate bearing capacity of the wallboards by 12%, 8%, and 56% respectively. The result of this study can provide references for the research and application of light steel frame to form LSSCFAFW.
首先分析了生产安全事故调查报告中导致事故发生的实际原因,再针对企业安全管理制度不落实的问题,探究其主要表现形式和原因,并借鉴制度审计的方法理论,构建安全管理模型促进制度落实.研究表明:促进企业安全管理制度的落实需要在确保规章制度科学性和可行性的基础上,采取管理方法和技术手段提高安全管理人员责任意识、提高岗位作业人员安全意识和规章意识,辅以监督检查和绩效考核的管理措施.
On the basis of the research of many scholars,the method of questionnaire survey is used to investigate,sort out and improve the problems existing in the construction of safety culture in small and medium-sized industrial and trade enterprises,and to find out the main problems in the construction of safety culture in their enterprises.Ac-cording to the existing problems,through the implementation of a series of external forces and internal measures,strengthen the construction of safety culture in enterprises,so as to drive and facilitate the safe production and susta-inable development of small and medium-sized industrial and trade enterprises.
In order to promote the application of compressed air foam extinguishing system in transformer fire pro-tection,and to ensure the fire safety of converter stations and substations,the spray range of the compressed air foam sprinkler system was studied through experiments.The variation rules of spray range with spray aperture,spray pres-sure,spray angle and branch pipe length were analyzed,the results were as follows:① The spray range decreases with the increase of the spray aperture,and increases with the of the mixed liquid flow rate.②Within a certain range,the spray range increases with the increase of the spray pressure,and stay the same when it reaches a certain limit value.③With the increase of the spray angle,the spray range first increases then it decreases,and reaches the maximum when the spray angle is 30°.④The length of the branch pipe has basically no effect on the spray range.
Before the identification and evaluation of safety risks,we should first identify the hazards and hidden dan-gers in the workplace,equipment and facilities,operational activities,etc.And then,we use qualitative or quantitative evaluation methods to evaluate the safety risks that may be caused by the hazards and hidden dangers,and take differ-ent control measures.Based on the LEC method of operating condition risk analysis,we carry out the hazard source identification and risk evaluation for the construction activities of the dust collector,and then,we fotmaulate specific risk prevention measures.
The coke oven production process involves explosive gases and multiple explosive hazardous environ-ments,and effective control of the risk of coke oven fire and explosion accidents is an important task for the safety management of coke plants.According to the principle of combustion science,this paper puts forward countermeasures and measures to reduce the fire and explosion accidents of coke ovens from the aspects of Intrinsic safety of equipment and facilities,interlock control,process operation and maintenance management.
In order to analyze the effectiveness of safety investment and improvement measures,an improved method of basic-element knowledge ecosystem is given.This method preserves the logical relationship between the sentence meaning and the main object in the original text,and adds the concept of basic-element knowledge string and basic-element knowledge tree.The method is applied to analyze the utility of safety inputs,which results in a chain of primi-tive knowledge related to the problem.The process leading to the utility problem is analyzed and improvements are proposed based on the process.Examples of safety inputs that lead to increased economic losses are analyzed.The re-sults show that the direct reasons for the economic losses are the safety investment,the increase of the working face and the gas-electricity linkage design of the equipment.Deeply,it is caused by the group's ineffective supervision and the pursuit of self-interest of the second-class mines.Finally,corrective measures for safety investment are proposed.
This paper aims to propose an emergency drainage scheme for emergency rescue of underground plant cav-ity groups from the perspective of flooding plant emergencies in pumped storage power stations.Taking a pumped stor-age power station as an example,on the basis of the overall drainage demand and the actual spatial structure charac-teristics of the underground plant cavity group,this paper proposes a comprehensive emergency drainage scheme of self-drainage of the power station in the early stage,multi-vehicle tandem drainage in the middle stage,and"water ex-traction+storage+drainage"in the late stage.The key parameters such as flow rate,head and pipe diameter of emerg-ency drainage equipment are determined for each stage.
In order to better promote the healthy development of marine fishery and accelerate the carbon peak pro-cess in the field of marine fishing vessels.This paper uses ONRL fossil fuel combustion method and IPCC emission factor method to calculate the fuel consumption and carbon emission intensity of Chinese marine fishing vessels,anal-yzes the main factors affecting the carbon peak of marine fishing vessels from many angles.For example,the aging of the hull is serious,the fishing equipment is backward,the hull construction materials are backward,there are many wooden fishing boats and the diesel combustion occupies the main body,and the energy consumption and pollution are serious and so on.So as to put forward specific emission reduction strategies.For example,the application of new energy-saving materials such as FRP,aluminum alloy and polyethylene,the application of low-carbon clean energy technologies such as lithium battery power,LNG power,methanol power and hydrogen power,The application of new equipment and technologies such as lightweight fishing machinery and equipment,fish sonar detection,AIS net posi-tioning instrument,INS comprehensive conduction and exhaust heat refrigeration,and the development of the emerg-ing industry--marine recreational fishery and so on.
Based on the soil test data of three typical soils(peat soil,clay,and silt)in foundation pit engineering in Kunming area,this paper carries out normality test for basic physical indexes.Correlation analysis was conducted be-tween an HSS model parameter(tangent stiffness for primary oedometer loading Eref oed)and basic physical indexes for three soils.The results show that:① the compression modulus(Es0.1～0.2)of peat soil,clay,and silt in Kunming area follows lognormal distribution,and tangent stiffness for primary oedometer loading approximately follows lognormal distribution.② The liner relationship of tangent stiffness for primary oedometer loading for peat soil,clay and silt in Kunming area are 0.85Es-peatsoil,0.89Es-clay and 0.86Es-slit respectively.③ When the compression modulus is not consid-ered,it is established multiple regression model of tangent stiffness for primary oedometer loading of peat soil,clay and silt with density,moisture content and initial pore ratio,which can be expressed as Erefoed=w0.699ρ-1902e-2.061 0(peat soil),Eref oed=w0.699ρ-1.935e-2.259 0(clay)and Eref oed=w0.423e-2.034 0(silt).The above empirical equation can be used as a reference for cal-culating the tangent stiffness for primary oedometer loading of peat soil,clay,and silt in Kunming area.
In order to determine whether the bearing capacity and dynamic characteristics of a steel box combination girder bridge in Kunming under the service load meet the design expectations,the load test of the bridge is carried out.Through the method of finite element numerical simulation analysis and on-site load test,the stress and deflection of the control section under various working conditions of the bridge under the static load test are adopted,and the modal parameters and dynamic response of each working condition are obtained by combining the dynamic load test,and the measured value is analyzed and compared with the theoretical value.The results show that the deflection calibration coefficient of the bridge is 0.77-0.85,the strain calibration coefficient is 0.697-0.776,the maximum relative residual strain is 18％,the maximum first-order vertical bending frequency is 2.38 Hz is greater than the theoretical value,and the measured maximum damping ratio is 1.86％.In the barrier-free driving test and braking test,the maximum impact coefficient is 0.025,and the maximum dynamic strain is 26 με.It can be seen that the bearing capacity and stiffness of the bridge meet the requirements under the static load test,and the maximum relative residue does not exceed the limit of 20％.Data from dynamic load tests show that the bridge meets the requirements for driving comfort.
In order to improve the safety management efficiency of large iron and steel enterprises and realize the vis-ualization of dynamic risk management,the article combines the hierarchical analysis method and the expert survey method,and establishes a typical regional dynamic safety risk assessment index system for large iron and steel enter-prises based on the assessment dimensions of inherent risk and dynamic risk.Taking a large iron and steel enterprise as an example,the article collects the existing data of the enterprise,investigates the needs of the enterprise on the spot,establishes a regional dynamic safety risk assessment model,determines the weights of the indicators,calcula-tes the regional risk index,and specifies the regional safety risk level.The results show that:the established regional dynamic safety risk assessment model makes up for the defects of the existing index system,which is inherent with the imperfect and unclear dynamic risk indexes,further mines the data,realizes the effective assessment of the enter-prise's regional dynamic safety risk,has feasibility and popularization,and provides practical experience for the as-sessment of the regional dynamic safety risk of iron and steel enterprises.
The dust ignition data and its molecular structure were first obtained from the GESTIS-DUST-EX data-base,then the molecular descriptors describing the minimum ignition energy of the dust were filtered by quantum chemical calculations,and then the random forest algorithm was used to rank the importance of the features reflected by the molecular descriptors.By comparing ten commonly used binary classification models,it is found that the binary classification models built by random forest and support vector machine methods are superior,and they have achieved over 90％accuracy,precision,recall,and F1 values.Finally,this paper provides an in-depth analysis of the molecular descriptors with high importance ranking in the binary classification models to elucidate their intrinsic connection with MIE.The results of this research can be used to quickly grasp the explosion hazard of combustible organic dusts and provide guidance for the prevention and control of industrial dust accidents.
Combined with the existing actual pipe network information and fault analysis results,this paper constructs a heating pipe network risk assessment index system covering the risk possibility of heating pipe network and the sev-erity of accident consequences,introduces the heating pipe network risk scoring method,and the hierarchical analysis method and entropy weight method are introduced for combined assignment to establish the risk assessment model of heat supply pipeline network.Finally,an example of a heating pipe network in an urban area is analyzed to verify the effectiveness of the risk assessment model.The results show that the model integrates the characteristics of pipe net-work,expert opinions and accident information,and can accurately evaluate the risk of heating pipe network.
In order to reduce the safety risk of garage personnel,using computational fluid dynamics software and on-site monitoring equipment,the diffusion law of CO pollution was studied when the car was idling in the garage and after parking.The results show that a wake area is formed at the car rear when a car is driving,and CO rises in the form of smoke plume for a certain distance and diffuses around the area,and the concentration decreases with increasing height;One minute after the car stalls,the CO concentration around the car body rises first and then decreases,and the concentration dilutes slowly,always higher than the ambient background concentration.The actual measurement sho-ws that the maximum concentration of CO in the garage caused by automobile exhaust emissions is 20.5 mg/m3,which causes the indoor air CO in the garage to exceed the standard.The research results provide a reference for design and optimization of exhaust emission reduction and ventilation system of underground garage.
Coke oven flue gas is a low-grade heat source that can be used for indirect ammonia evaporation after de-sulfurization and denitrification purification.The author has studied the process flow,main equipment,operating para-meters,and other key points of indirect ammonia evaporation from coke oven flue gas waste heat,and provided rea-sonable process flow and control parameters,achieving effective utilization of coke oven flue gas waste heat.
The purpose of the present paper is to argue for the broader application of establishment-level safety analy-tics.This is accomplished by defining the terms,describing previous research,outlining the necessary components re-quired,and describing knowledge gaps and future directions.The knowledge gaps and future directions for research in establishment-level analytics are categorized into readiness for analytics,analytics methods,technology integration,data culture,and impact of analytics.
In order to solve the problem of difficult fault diagnosis due to the lack or insufficient collection of char-acteristic sample data of internal leakage of pipeline valves,a fault diagnosis model of internal leakage of pipeline val-ves based on deep convolutional generative adversarial network(DCGAN)and one-dimensional convolutional neural network(1DCNN)is proposed.Firstly,the small sample data of acoustic emission signals under different operating conditions of the valve are pre-processed by Numpy and Pandas modules in Python and Matplotlib function for nor-malisation and visualisation.Secondly,the pre-processed data are input into DCGAN to compensate for the generation of enhanced datasets.Then,the hybrid dataset is fed into the 1DCNN model for training.Finally,the confusion matrix was used for model performance evaluation.The results show that the DCGAN-1DCNN model achieves an average F1 score of 0.97 at 75％of the generated dataset,which has a higher accuracy and recall rate compared to a single 1DCNN model diagnosis.
Taking a national reserve base as an example to study and analyze,set the sudden initial accident scenario,based on the Domino effect theory and Bayesian network,analyze the domino effect propagation process,divide the accident process time interval according to the tank burnout time and tank failure time,and establish the Bayesian dy-namic network analysis model of the domino accident propagation process,so as to obtain the accident probability of each storage tank in different time intervals after the initial accident,and provide a theoretical basis for the emergency decision-making of the Domino effect accident in the oil reserve reservoir.
By analyzing the influencing factors of employees'safety behavior,an evaluation system of group safety behavior of metallurgical enterprises employees including 10 secondary indicators is established from three aspects of safety awareness,safety attitude and safety skills;Then use the analytic hierarchy process(AHP)to determine the in-dex weight;Then the fuzzy comprehensive evaluation method is used to determine the safety behavior level of em-ployees.Finally,40 employees of a metallurgical enterprise in Wuhan were selected for an example evaluation.The results showed that the safety behavior evaluation level of the 40 employees interviewed was"medium",and the results were consistent with the actual survey,indicating the effectiveness and reliability of the evaluation model.
