Hoisting machinery as a material handling equipment, widely used in the national economy departments, in the national “safe, efficient, green and harmonious” under the application requirements, to ...improve the intrinsically safe hoisting machinery, a complex system, in this paper, the affecting the safe operation of the hoisting machinery hazards, summary and analysis based on the intrinsic safety theory and correlation analysis method, on the nature of the hoisting machinery safety assessment model is established. The theory of information entropy and fuzzy mathematics, the safety evaluation method of hoisting machinery based on neural network is studied. Through summarizing the hazard factor of hoisting machinery, lifting machinery design, manufacture, installation, alteration, use, and management and so on, this paper analyzes advantages and disadvantages of commonly used safety assessment or prediction method, based on the “human–environment” of safety evaluation of ideas, will influence of lifting machinery into the ontology equipment hazards, organizational security hazards, essence of safety culture and emergency fault handling of hazards. In the paper, two neural networks are used to predict the failure rate, and the accuracy of the two methods is compared. Firstly, BP neural network is optimized by genetic algorithm for prediction. BP neural network optimized by genetic algorithm is the most widely used neural network for prediction. Secondly, Elman neural network is used for prediction. Two neural networks are used to predict the failure rate, study the structural weight of neural network, obtain the prediction result graph and prediction error graph of neural network, and analyze the results, so as to judge the availability of using neural network method to predict the failure rate.
The frequent occurrence of various sudden natural disasters in the world has caused heavy losses to human beings. It is very important to forecast the demand of emergency materials in order to ...protect people's safety and property. The purpose of this study is to use IACO-BP algorithm to forecast the demand of emergency supplies in the case of flood disaster. In this study, the flood disaster situation in recent years published by the Ministry of Water Resources of China is selected as the experimental data set. The data are sorted and analyzed by a variety of theoretical comprehensive operation, qualitative and quantitative research method, analytic hierarchy process and system dynamics method. The improved ant colony optimization algorithm is used to model the emergency material demand, and the population, flood level, flood level of the disaster area are analyzed. As the network input, the material situation outputs the material demand, so as to forecast. The results show that the iteration times of IACO-BP algorithm are 11 and the running time is 3S. The fluctuation of IACO-BP algorithm is the least and the most stable among the three algorithms. The material satisfaction degree predicted by IACO-BP algorithm is improved by 15% from the original 80.9%. It is concluded that this algorithm is very accurate and efficient in the prediction of emergency material demand, which can better assist the disaster situation. This study contributes to the prediction of emergency material demand for emergency disaster.
•Influencing factors on water spray cooling in non-boiling area are analyzed.•The influence of evaporation intensity on spray cooling performance is analyzed.•The optimal angle between aircraft and ...the gravity is provided for spray cooling.•Experimental dimensionless correlations of Nusselt number are developed.
In this paper, the performance of a water spray cooling system is investigated experimentally. The influence factors including the nozzle atomization effect, spray height, heat flux, inlet pressure and gravity angle are discussed. Results show that under the same operating conditions, the main influencing factor is the spray mass flow rate involved in heat transfer. Heat transfer performance becomes better with the increases of mass flow rate. For the same nozzle, the best heat transfer performance appears under the critical height. The performance of spray cooling is improved with the growth of inlet pressure and evaporation intensity under the same inlet temperature. Furthermore, the heat transfer performance is closely related with the gravity angle. The best heat transfer performance appears when the gravity angle is between 30° and 120°. Heat transfer performs the worst when the gravity angle reaches 180°. Besides, experimental dimensionless correlations of Nusselt number are given in non-boiling area with water coolant.
China is located in the intersection area of two seismic zones. Due to this special geographical location, earthquake disasters occur frequently in China. Earthquake emergency rescue work is one of ...the key construction works of disaster prevention and mitigation in China. This paper mainly studies the earthquake disaster rescue model based on the complex adaptive system theory and establishes the earthquake disaster rescue model by analyzing the complex adaptive system theory and combining the earthquake rescue process. In this paper, through the task allocation mechanism task, the disaster rescue task is divided into simple task and complex task, and the executive task subject is divided into single task subject and multitask subject. On the basis of considering the shortest emergency rescue time goal and the goal of maximizing the deployment utility of rescue team, the reasonable deployment of a rescue team is realized through a complex adaptive system, that is, the deployment utility of the rescue team is maximized. In this paper, the simulation experiment and comparison of the earthquake disaster rescue model based on the complex adaptive system theory are carried out. The experimental results show that the model used in this paper is better than the other two models in terms of algorithm convergence, rescue number, and overall score; in different scenarios, the relative survival probability of the model in this paper is 58.92%, 67.85%, and 77.46%, and the proportion of the wounded rescued is 66.31%, 76.45%, and 83.06%, which were higher than those of the other two models. The earthquake disaster rescue model based on the complex adaptive system theory proposed in this paper provides an effective theoretical basis and method system for postdisaster emergency rescue decision making and enhances and improves the emergency response ability to deal with large-scale geological disaster events.
The thermal comfort of an enclosed room with air conditioner and air-distribution duct coupling can be studied, and the parameters of a split-fiber air conditioner can be optimized on the basis of ...studying the thermal comfort of various parts of the human body. In this paper, a room model with a distributed air conditioner was proposed. First, the rationality of the three thermal comfort characterization models of predict mean vote (PMV), predicted percentage of dissatisfied (PPD), and percentage of dissatisfied (PD) were verified through experiments and simulations. Then, the temperature and thermal comfort of various parts of the human body were explored when the air-distribution duct had different openings and different positions of the air outlet. The simulation results showed that compared with other situations, when the split-fiber air conditioner had three rows of holes (5-o’clock, 6-o’clock, 7-o’clock) and the air outlet was located in the middle of the right wall of the human body, the PMV, PPD, and PD of the measuring points around the human body fluctuated less, the indoor temperature field distribution fluctuated less, and there was no wind feeling around the human body, which can better meet the needs of human thermal comfort.
The post-peak behavior and fracture characteristics of hard rock are correlated with the stability and bearing capacity of engineering rock mass. However, there are relatively few research studies on ...the post-peak mechanical behavior and fracture characteristics of hard rock under true triaxial stress. Therefore, this study carried out relevant true triaxial compression tests and acoustic emission (AE) monitoring. It is concluded that under a true triaxial condition, the number of post-peak steps increases first and then decreases with the increasing
σ
2
, which implies that the rock failure evolves from shear failure to a more complex tension–shear mixed failure and finally evolves into a failure mode dominated by tensile failure. The overall level of the rock fracture angle (
θ
) at low
σ
3
is higher than that at high
σ
3
. In the range of stress level in this study, when
σ
3
is high, the fracture angle of granite increases with increasing
σ
2
, and its regularity is obvious, while when
σ
3
is low, the regularity of the fracture angle increases with the increasing
σ
2
is not obvious. It is found that there are three different types of cracking processes in granite. Meanwhile, the expansion rates of three different racking types are calculated by simplified treatment, which are about the order of 10
−5
–10
–4
m/s. The research results of this study could supply a useful reference for the understanding of deep hard rock fracture behavior.
The shield machine tunnelling along the curve section causes more disturbance to the surrounding environment than the straight section. Pile foundation is the most commonly used foundation form in ...high-rise buildings, and high-rise buildings have extremely high requirements for controlling non-uniform deformation. Therefore, it is necessary to study the surface settlement and the deformation law of pile foundations caused by shield machine tunnelling along the curve section. Considering the shield machine tunnelling factors along the curve section and the coupling effect of piles and soil, the analytical calculation formula of the ground settlement and the pile foundation deformation caused by the shield machine tunnelling along the curve section is deduced. According to the actual project situation, a finite difference model (FDM) is constructed, and the correctness of the FDM and analytical prediction formula is verified by comparing the on-site monitoring data. The research shows that the error among the FDM results, the analytical prediction results, and the on-site monitoring data are small, and the surface settlement and pile foundation deformation meet the construction control standards. The friction resistance of the shield shell, the integrative gap at the shield tail (IGST), and the over-cutting gap (OG) are the main factors leading to the surface settlement. However, the shield shell friction and OG are the main reasons leading to the inner settlement of the curve section being more prominent than the outer side. The difference in the pile foundation settlement on both sides of the curve section is slight, the maximum settlement difference rate is 1.8%, and the maximum horizontal deformation rate of the pile foundation on the inner and outer sides is 9.2%, which shows that the horizontal deformation of the pile foundation is more sensitive to the asymmetrically distributed construction factors.
As population density increases, environmental hygiene and public health become increasingly severe. As the space where residents stay for the longest time and have the most profound impact on their ...physical and mental health, the quality of the environment in urban communities largely determines the degree to which residents engage in physical activity, bear the risk of pollution exposure, and obtain healthy food. Therefore, in order to ensure the physical and mental health of residents, this study proposes community planning guided by environmental hygiene and public health, and establishes an environmental health assessment system for this purpose. This system evaluates the community environment from four aspects: land use, service facilities, site convenience, and environmental quality. Established the diversity, density, road network connectivity and facilities accessibility nine criteria, as well as the land function of mix, plot ratio, food environment, network ring
and connected
index, pavement risk level, green configuration and neighborhood material environment disorder degree of 27 indicators of community built environmental evaluation index system. The data is collected through field survey, questionnaire distribution, resident interview and data mapping, and the established evaluation index system is used to evaluate the construction environment of the community. The experimental research data included population data, CAD plan, land use data, street data, POI point data, building data and bus station data, etc. 273 questionnaires were distributed, 264 were recovered, 8 invalid questionnaires were removed, and 256 valid questionnaires were obtained. These experiments confirm that land use, service facilities, site convenience, and environmental quality have a significant impact on the built environment of communities, with impact weights of 0.513, 0.227, 0.135, and 0.125, respectively. The above weights are calculated based on the index judgment matrix and the eigenvectors. The scores of land use, service facilities, site convenience, and environmental quality for the study subjects were 3.44, 1.46, 0.94, and 0.51, respectively, among them, the land use score is less than 3.85, the 1 service facility score is less than 1.71, the site convenience score is less than 1.01, and the environmental quality score is less than 0.94; indicating that the community has serious problems such as single land use types, pollution exposure, and difficulty in obtaining healthy food. Therefore, community planning and transformation based on land use, service facilities, venue convenience, and environmental quality can effectively improve the physical and mental health of residents. In the specific community transformation plan, artificial intelligence and data-driven methods can be used to optimize the land use plan, service facility configuration, site convenience transformation and environmental quality improvement, so as to formulate the optimal community transformation plan and improve the comfort and happiness of community residents. In the future, on the basis of the existing research, the selection of community types will be further enriched and the research cases will be expanded. And through the in-depth practical study of the case, the constructed evaluation index system is optimized and improved to make it more scientific. At the same time, as urban renewal and design have entered the era of stock planning, based on the more perfect evaluation index system, more specific and detailed system discussion of the built communities with public health problems, in order to provide more detailed services for the construction of a better and healthy living environment in the future.
There are various discontinuities in geotechnical engineering problems, which can be roughly divided into two types: one is the discontinuities formed by various actions of rock and soil, such as ...joints, faults, fissures and shear failure surfaces in rock mass; The other is the contact surface between geotechnical structures such as various foundations, retaining structures, underground structures and geotechnical bodies. Therefore, we cannot ignore its existence in computation. At present, the finite element method and other numerical methods have been widely used to solve geotechnical engineering problems, but the solution of the above discontinuous deformation problems has not been well solved. In this paper, the constitutive model of rock and soil is established. Based on the theory of image processing technology, the common methods of dealing with discontinuous deformation problems in finite element method are pointed out, and the unreasonable points are pointed out. It is more reasonable to treat such problems as contact problems, because it can reflect the main characteristics of discontinuous deformation surface. Come on. The three-dimensional image of the constitutive model has three important functions: (1) it is helpful to enhance the theory of constitutive theory and lay a foundation for further mastery of the theory of constitutive theory; (2) Abstract constitutive theory is no longer just a bunch of boring formulas, which is helpful for beginners to improve their interest in learning the theory of constitutive theory. (3) Finally, a three-dimensional image constitutive model of rock and soil is established through experiments, and the program written by MATLAB is compared with the test results of conventional triaxial compression of rock and soil, which fully verifies the correctness and effectiveness of the constitutive model of rock and soil established in this paper.
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