Adopted numerical simulation and experimental testing to research the dust-removing mechanism of the full-section fog curtain trapping network, solve the problem of dust pollution in the roadway by taking the dust reduction in the return-air lane of the working face. The porous media model was employed to investigate the impact of dust traps with varying apertures on dust removal resistance. The inertial resistance coefficient C2 and viscous resistance coefficient D were derived to simulate the dust traps under different wind speeds and mesh sizes of the traps. The optimization of the average water film thickness (h) by different nozzle flow rate (alpha), dust trapping mesh (beta), and wind speed (c) is analyzed by the response surface method. The influence of its change on the formation of the water film is tested, and the dust removing effects of the spray and the water film are compared through experiments. The resistance of the dust catcher mesh to the removal of dust was arranged from high to low as follows: 120 mesh, 40 mesh, and 80 mesh. The influence of each parameter on the average water film thickness was analyzed as alpha > c > beta. The optimal film-forming parameters were obtained as follows: nozzle flow rate, alpha = 6 L/min; dust-trapping mesh, beta = 120 mesh; wind speed, c = 6 m/s. The average water film thickness formed is 0.341 mm. The optimal spray particle size for the formation of a water film is 0-60 mu m. The optimal dust removal rate of its water film is 92.6 %, which is better than the dust removal effect of spraying.
为促进煤矿瓦斯抽采智能化技术的进一步发展,提升瓦斯抽采效果与技术水平.通过查阅、统计、分析相关文献资料,总结了我国煤矿瓦斯抽采在钻孔施工与密封、抽采数据监测与传输、抽采达标评判、抽采参数分析与设备调控四个方面的智能化发展技术现状,提出了煤矿瓦斯抽采智能化技术组成结构与未来发展方向.研究结果显示:现有煤矿瓦斯抽采智能化技术以自动化、综合化、可视化和数字化的协同发展为主,未来发展方向为抽采能力智能调配、抽采管网气体泄漏智能识别和抽采全过程一体化控制.
针对瓦斯测压过程中钻孔孔外导气连接装置气密性不足、操作不方便和功能单一等问题,研发了一种密封可靠并具有多个接口的测压钻孔孔外导气管连接装置.首先,对测压钻孔孔外导气管连接装置进行了设计,然后制定了气密性检测实验方案,并提出了用于该连接装置的多种密封方法,开展了气密性检测对比实验,分析了实验数据,研究结果显示:利用密封圈、四氟垫和黄铜材质零件组成的孔外导气管连接装置在气密性、应用便捷、功能多样化和性价比方面最佳,该装置为准确测量瓦斯压力提供了有力的保障.
Dynamic economic dispatch(DED)of power system is a complex multi-objective optimization problem that aims to minimize the total fuel cost and pollution emissions of generating units.However,due to the complexity of the constraints,general mathematical methods are difficult to solve this problem.Therefore,this paper adopts the swordfish optimization algorithm(SFO)to solve the dynamic economic dispatch problem considering wind power.In order to verify the performance of the SFO algorithm,this article uses the test sys-tem of 5 thermal power units,and simulates and tests the model in MATLAB software.Experimental results show that the SFO algorithm can effectively reduce the fuel cost and pollution emissions of the power system,thereby improving the economic benefits of the power industry.
Natural disaster prevention and emergency management are important areas in the construction of the"Belt and Road",and the growing demand of cooperation among all parties,as well as the coexistence of universality and differences of cultures in different countries,make cooperation in emergency management take a cross-cultural communication turn.The different elements,such as communication subjects,communication links,and communication contents,will all affect the effect of cross-cultural communication.Through litera-ture research and case analysis,emergency management cooperation among countries and regions along the"Belt and Road"is facing difficulties in terms of normality and non-normality,intra-organizational and extra-organizational,cooperation mechanisms,etc.The"common meaning space"is limited,cultural shock and cultural misinterpretation,information barriers still exist,information barriers still exist,the hegemony of the disourse of the Western powers has weakened the construction of group identity in the"Belt and Road".The active participation of grassroots people is not high,and the field of cooperation needs to be broadened and the level needs to be deepened.In order to promote emergency management cooperation among countries and re-gions along the"Belt and Road",the principle of"inter-subjectivity"should be used to promote cross-cul-tural communication,the vision of building a community of destiny should be used to enhance the effectiveness of cross-cultural communication,the process of cross-cultural communication should be optimized with refer-ence to the"Yohari Window",and new media communication should be used as a carrier to expand the cover-age and The new media will be used as a vehicle to expand the coverage and influence of intercultural commu-nication.
In order to study the impact of the geological structure on the process and effect of pulsating hydrau-lic fracturing(PHF),the industrial experiments of PHF is carried out in the tectonic zone and the non-tectonic zone respectively,then the difference of the process and effect of pulsating hydraulic fracturing in the two cases is analyzed.The results show:The fault structure brings out a weak surface in pulsating hydraulic fracturing ar-ea,easily inducing seam crack extension to the fault,and pulsating water continuously moves towards the direc-tion of fault.The pulsating water injection time and injection volume of of PHF in the tectonic zone are signifi-cantly larger than those in the non-tectonic zone,which has a large water blocking effect on gas drainage and hinders the dynamic process of gas migration;The natural pressure relief zone of the fault prevents the pulsa-tion pressure from rising during hydraulic fracturing process,which reduces the effect of PHF;The geological structure reduces the increment of stable gas drainage concentration before and after PHF,and improves the in-itial concentration of gas drainage.
In order to improve the accuracy of outburst prediction in the No.21coal seam excavation working face of the No.9 Coal Mine,acombination of on-site experiments and theoretical analysis was used to obtain the sensitivity ranking of the outburst prediction indicators of the No.21 coal seam excavation working face of the No.9 Coal Mine,such as the initial velocity of drilling gas emission(q),the desorption indicators of drilling cuttings gas(Δh2、K1),and the amount of drilling cuttings(S),as M(q)>M(Δh2)>M(K1)>M(S).The dimensional analysis method is used to analyze the applicability of the initial velocity index of gas emission from boreholes.The research results show that the initial velocity of gas emission from boreholes is the best for the outburst prediction of No.9 Coal Mine No.21 Coal Seam,which reflects the most comprehensive coal stress,coal strength,and gas occurrence.The critical value of the initial velocity(q)index of gas emission from boreholes is determined to be 4.5 L·min-1 through theoretical calculation.
Coal measures limestone is a common rock type in coal resources,which has important geological and engineering significance.In this paper,the microstructure of limestone is analyzed by means of CT scan-ning and casting thin section.The cast thin section provides the detailed characteristics of the rock under the microscope,while the three-dimensional internal structure information of the rock is obtained through the CT scanning image,and a series of parameters such as porosity,connectivity,pore diameter,etc.of the meas-ured core are calculated.The pore structure,mineral composition and microstructure of limestone are studied by comprehensive analysis of these two data.It is found that the limestone in this area is mainly fine-grained dolomite,secondly calcite,and the argillaceous material is mainly clay minerals.The structural fractures of rock are developed and interwoven into a network,with uneven distribution in pores,poor connectivity and low heterogeneity in the same direction.The porosity measured by CT scanning is 4.37%～9.66%,and the con-nectivity is high.By comparing and correlating the two data,the microstructure characteristics of limestone are revealed,and then the engineering properties are further understood.
With the continuous improvement of urban planning and construction layout,a large number of large shopping malls have emerged across the country,which are often densely crowded,and if a fire breaks out,whether the rapid and safe evacuation of personnel is particularly important.Based on Pathfinder soft-ware,different evacuation modes under fire conditions in a shopping mall are simulated,and the optimal mode of the shopping center is solved,and the effects of different evacuation modes on evacuation time,evacuation exit utilization and evacuation tool utilization are discussed.The results show that the escalator coupled with double downward movement on the basis of the evacuation staircase has the best evacuation effect,which takes 466 s.Evacuees are not familiar with the evacuation exits of the shopping center,and should set up obvious exit signs,and allocate professionals to guide evacuation to avoid losses caused by concentrated congestion;Slow-moving people such as children and the elderly can improve efficiency by using fire elevators for evacua-tion.The research results can provide a reference for fire evacuation in large shopping centers.
A prediction method based on adaptive neuro-fuzzy inference system and improved real-coded quantum genetic algorithm is proposed to improve accuracy of coal and gas outburst dangerous level.The fuzzy rules of ANFIS is extracted directly from sample data by data-driven method,and an adaptive neuro-fuzzy in-ference system for coal and gas outburst prediction is established.In view of the low accuracy of ANFIS pre-diction and the large number of parameters of fuzzy reasoning system,an improved quantum genetic algorithm is used to train adaptive neuro-fuzzy inference system.The Archimedes spiral space search mechanism of the bald eagle search algorithm is introduced into real-coded quantum genetic algorithm to update individual,and the differential mutation mechanism is mutate the worst individual to maintain the diversity of the population,and Gauss-Cauchy mutation is used to alternate the optimal individuals to help them escape from the local ex-tremum region quickly and accelerate the iteration speed of the algorithm.The different forecast methods are conducted on typical engineering practical data of coal and gas outburst.The results show that IRQGA can yield a superior optimization performance to other algorithm,and the prediction accuracy of the IRQGA-ANFIS method is 94.44%,and the MAEs in 30 rounds of independent operation of the model built in this paper re-duce by 0.0245,0.1184 on average,and the MSEs reduce by 0.0162,0.1849 on average,and the RMSEs re-duce by 0.0172,0.1721.The model built in this paper has better forecast ability and more accuracy for pre-dicting the outburst fatalness.
In order to deeply analyze the safety behavior of coal miners,the prospect theory and evolutionary game theory are combined to construct a coal miner-security inspector game model,analyze the stability of the strategy choice of the game party,and use MATLAB to conduct numerical simulation experiments to analyze the effects of labor and mental cost perception,reward perception and penalty perception on the evolution of coal miners'safety system.The main contribution of this paper is to incorporate the perceived value of participants into the game model based on prospect theory,so that the strategic choice of the game subject is closer to real-ity.The results show that labor and mental cost perception are negatively correlated with the safety behavior of coal miners and security inspectors,and reward perception and punishment perception are positively correlated with the safety behavior of coal miners and security inspectors.The research results provide suggestions for the safety management of coal enterprises from the aspects of reducing safety production costs and improving the reward and punishment mechanism.
To solve the problem of severe deformation and damage to the underlying coal seam recovery roadway in close-distance coal mining groups,which affects the safe and efficient mining of the working face,this study focuses on a mine in the southwest of Shandong Province,China.Through theoretical analysis,nu-merical simulation,and combining the results of in-situ stress testing and mechanical experiments,the mutual influence between coal seams during close-distance coal mining and the manifestation of strata pressure in each coal seam are investigated.The results show that after coal mining,the stress beneath the working face decreases as it moves away from the roadway side,but the stress no longer decreases after reaching a certain distance.By comparing and analyzing three different layouts of underlying recovery roadways,namely overlap-ping,dislocation,and insetting,it was found that the insetting layout resulted in the least deformation of the sur-rounding rock of the underlying recovery roadway.Based on the deformation of the surrounding rock in the un-derlying coal seam recovery roadway with the insetting layout,corresponding support schemes for the surround-ing rock are proposed.The optimization of surrounding rock stress and deformation control showed significant effects,enabling effective control of the roof of the recovery roadway during the underlying coal seam mining process.The research findings have important reference value for the layout and support optimization of close-distance coal seam mining roadways in mining areas with similar geological conditions.
In recent years,with the popularity of air conditioning in university dormitories,the electricity con-sumption of student dormitories has gradually increased.As the primary component of electricity consumption,analyzing the electricity consumption characteristics of air conditioning and predicting the electricity consump-tion can help with electricity safety management and dormitory wiring planning.In addition,it can also help students to plan the use of air conditioning rationally,prevent safety risks caused by circuit overload.We pro-pose a method for short-term electricity consumption prediction in college dormitory air conditioning based on Bi-LSTM recurrent neural networks.By collecting data on electricity consumption of air conditioning in uni-versity dormitories and establishing a dataset for short-term electricity consumption prediction,we use a Bi-LSTM network to extract the temporal information of electricity consumption samples,while incorporating regu-larization into the network to avoid network degradation problems.Based on this,we use our model to make predictions of electricity consumption for the next day.Experimental results show that the proposed model has a clear improvement in prediction accuracy and stability compared to traditional prediction methods.We first preprocessed and extracted features from the dataset,including cleaning the data,clustering,normalizing the data,and selecting features.Then,we trained various prediction models with the preprocessed data and com-pared them.Finally,we chose the Bi-LSTM recurrent neural network model to predict short-term electricity consumption.In practical applications,this method can help dormitory management departments in universities to predict the future electricity consumption of air conditioning for the next day more accurately.In turn,the administrators adjust equipment running status and rationalize the planning of electricity use to a-chieve energy conservation,emission reduction and optimization of equipment utilization efficiency.
Aiming at the situation that"the large breaking step of the roof slab directly overlying thick and hard sandstone is easy to cause coal-rock dynamic disasters such as coal wall ganging",this paper studies the min-ing process of 14121 working face in Zhangji mine,which has thick and hard sandstone as the roof slab,and combines with theoretical analyses to find out the influencing factors of the coal wall ganging,and determines the reasonable breaking step.Adopting pre-cracking blasting to force the roof release programme,simulating the effect of roof cutting with UDEC software,comparing the stress concentration at the coal wall before and af-ter cutting the roof by pre-cracking blasting at different breaking steps and the damage characteristics of the coal body in the plastic zone.The results show that:compared with 25m roof breaking step,15m roof breaking step makes the peak over-supporting stress in front of the coal wall decrease by 20.1%,but the bearing capac-ity of the coal wall increases by 121%,the maximum horizontal displacement of the coal wall decreases by 35.3%,and the range of the plastic zone of the coal wall decreases by 30%,thus reducing the occurrence of the accident of the coal wall flake gangs,and guaranteeing the safety of the large-height working face.
A liability insurance contract is a typical contract for the interests of the third party.Granting the right of direct claim to injured third parties is an objective requirement and inevitable trend in the development of the legal system of liability insurance.Article 15 of Implementation Measures for Work Safety Liability In-surance follows the second paragraph of Article 65 of the Insurance Law and attaches conditions to the exercise of rights for the third party.The attached conditions are that the insured's liability for a third party is deter-mined and the insured's reluctance to request the insurer to assume responsibility,which is the embodiment of adhering to the principle of relativity of contract and separation of traditional insurance law,and the condition that neglecting to request is the result of embodiment on the creditor's right of subrogation,which is inconsis-tent with the intent of legal norms and nature of the direct claim.The direct claim is a statutory independent claim right.In order to simplify the cost of exercising the right,there is no need to set the above two condi-tions as constituent elements,and it should be recognized that the direct claim of a third party arises naturally at the time of the damage accident.
In order to prevent serious casualties and property losses caused by gas explosion accidents in coal mine fire areas,the evolution process of gas explosion accidents in coal mine fire areas is studied by using knowledge elements,scenario construction,and deduction theory.Taking the gas explosion accident in a certain mine in July 2014 as an example,a coal mine fire area gas explosion accident scenario network based on dynamic Bayesian network prediction model is constructed from four dimensions:scenario state,emergency objectives,disposal measures,and disaster environment.The probability of accident scenario occurrence is cal-culated,and its evolution law is analyzed.The results indicate that the inferred results of gas explosion acci-dents in coal mine fire areas are basically consistent with the actual development scenario,verifying the ration-ality of the prediction model.The research results can provide technical support for the prevention of gas ex-plosion accident risk in fire areas,the improvement and improvement of emergency plans,and emergency deci-sion-making.
Under the background of the construction of intelligent mine ventilation system,online determination of wind resistance of the whole mine is one of the important technologies.The key to building an intelligent ventilation system is to obtain accurate and reliable ventilation parameters,but to achieve intelligent ventilation systems throughout the mine,a large number of perception sensors need to be installed.In order to solve the problem of online determination of wind resistance in resistance mines on the basis of limited sensors,the im-proved minimum tree principle is used to determine the optimal layout scheme of wind speed sensors.Starting from the principle of"wind measurement and resistance",the nodal pressure is used to meet the wind pressure balance of the circuit,the minimum number of pressure sensors installed in the wind network is determined,and the installation site is optimized,so as to obtain the branch air volume and node pressure wind pressure monitoring data of the whole mine.The above principle is applied to the ventilation network diagram of 23 branches and 16 nodes,and the results show that the wind resistance error is within 5%.
Based on the engineering background of 11 coal track roadway in Zhujixi Coal Mine,the coordinated control technology of"Grouting reinforcement is combined with high strength and high prestress anchor and borehole pressure relief"is proposed by theoretical analysis,numerical simulation and other methods combined with the actual field conditions and applied in the field.The results show that the deformation of roadway sur-rounding rock is mainly affected by the maximum shear stress,and the order of influence on the stability of roadway surrounding rock is:tectonic stress;Depth of roadway;Support density t;Support length.The opti-mized roadway reinforcement scheme is verified by numerical simulation.The maximum vertical stress of the roadway is 23.73MPa,the stress of the anchor cable is significantly reduced,and the plastic zone range of the roadway side and bottom is reduced.After the pressure relief of the borehole,the stress concentration zone is transferred to the area around the borehole,and the maximum stress is reduced to 22.5MPa.Combined with the field test results,the proposed restoration and reinforcement scheme can effectively control the deformation of surrounding rock in the chamber.
The auxiliary power supply system for electric locomotives provides power to the locomotive when it travels to an unpowered area or when the contact network is unpowered.In order to satisfy the chargingdemand and application environment of an electric locomotive auxiliary power supply system,this paper designs a charge for an electric locomotive auxiliary power supply system,choosing the topology of an uncontrolled rectifi-er plus an H-bridge integrated silecon carbide(SiC)power inverter module plus high-frequency transformer isolation and a fast diode rectifier circuit,as well as parameter calculations and the selection of core devices.Based on the DSP core controller,the charger control system design is completed,and the intelligent function is realized by adopting the constant current-constant voltage dual PI software control algorithm.Experimental re-sults show that the charger program design is reasonable,the control algorithm is reliable,and it meets the charging needs of the auxiliary power supply system of electric locomotives and application environment.
瓦斯抽采作为我国治理煤矿瓦斯灾害的根本措施一直受到广泛应用,提高瓦斯的抽采效率可以有效预防瓦斯事故,其中抽采负压对抽采效果有着重要作用.本文利用COMSOL软件建立抽采钻孔模型模拟瓦斯抽采,改变不同参数,观察不同条件下瓦斯压力云图以及等值线图,得出抽采效果具有时效性,抽采负压分布受多种因素影响,包括孔口负压、钻孔直径、抽采时间、封孔深度等因素.在新田煤矿进行现场试验,对不同条件下孔内负压分布进行对比测试,得出不同条件下抽采负压分布规律,形成以新田煤矿抽采负压为基础的瓦斯抽采技术优化体系,确定了合理的瓦斯抽采参数,有效提高了煤层抽采效果.
