In the present research,we proposed a scheme to address the issues of severe heat damage,high energy consumption,low cooling system efficiency,and wastage of cold capacity in mines.To elucidate the seasonal variations...In the present research,we proposed a scheme to address the issues of severe heat damage,high energy consumption,low cooling system efficiency,and wastage of cold capacity in mines.To elucidate the seasonal variations of environmental temperature through field measurements,we selected a high-temperature working face in a deep mine as our engineering background.To enhance the heat damage control cability of the working face and minimize unnecessary cooling capac-ity loss,we introduced the multi-dimensional heat hazard prevention and control method called"Heat source barrier and cooling equipment".First,we utilize shotcrete and liquid nitrogen injection to eliminate the heat source and implemented pressure equalization ventilation to disrupt the heat transfer path,thereby creating a heat barrier.Second,we establish divi-sional prediction models for airflow temperature based on the variation patterns obtained through numerical simulation.Third,we devise the location and dynamic control strategy for the cooling equipment based on the prediction models.The results of field application show that the heat resistance and cooling linkage method comply with the safety requirement throughout the entire mining cycle while effectively reducing energy consumption.The ambient temperature is maintained below 30℃,resulting in the energy saving of 10%during the high-temperature period and over 50%during the low-temperature period.These findings serve as a valuable reference for managing heat damage in high-temperature working faces.展开更多
This paper studies the time-dependent analysis of an M/M/1 queueing model with single,multiple working vacation,balking and vacation interruptions.Whenever the system becomes empty,the server commences working vacatio...This paper studies the time-dependent analysis of an M/M/1 queueing model with single,multiple working vacation,balking and vacation interruptions.Whenever the system becomes empty,the server commences working vacation.During the working vacation period,if the queue length reaches a positive threshold value‘k’,the working vacation of the server is interrupted and it immediately starts the service in an exhaustive manner.During working vacations,the customers become discouraged due to the slow service and possess balking behavior.The transient system size probabilities of the proposed model are derived explicitly using the method of generating function and continued fraction.The performance indices such as average and variance of system size are also obtained.Further,numerical simulations are presented to analyze the impact of system parameters.展开更多
采用多元回归分析原理及模型,结合回采工作面瓦斯涌出量的实测数据,利用SPSS(Statistical Product and Service Solutions)软件对回采工作面瓦斯涌出量的影响因素进行多元回归分析,建立了回归方程来预测回采工作面瓦斯涌出量。结果表明...采用多元回归分析原理及模型,结合回采工作面瓦斯涌出量的实测数据,利用SPSS(Statistical Product and Service Solutions)软件对回采工作面瓦斯涌出量的影响因素进行多元回归分析,建立了回归方程来预测回采工作面瓦斯涌出量。结果表明,利用SPSS软件直接对影响回采工作面瓦斯涌出量的因素进行回归分析,避免了复杂的推导与计算,预测精度较高。展开更多
基金supported by the National Natural Science Foundation of China (51874281)the Graduate Innovation Program of China University of Mining and Technology (2022WLKXJ006)the Postgraduate Research&Practice Innovation Program of Jiangsu Province (KYCX22_2612).
文摘In the present research,we proposed a scheme to address the issues of severe heat damage,high energy consumption,low cooling system efficiency,and wastage of cold capacity in mines.To elucidate the seasonal variations of environmental temperature through field measurements,we selected a high-temperature working face in a deep mine as our engineering background.To enhance the heat damage control cability of the working face and minimize unnecessary cooling capac-ity loss,we introduced the multi-dimensional heat hazard prevention and control method called"Heat source barrier and cooling equipment".First,we utilize shotcrete and liquid nitrogen injection to eliminate the heat source and implemented pressure equalization ventilation to disrupt the heat transfer path,thereby creating a heat barrier.Second,we establish divi-sional prediction models for airflow temperature based on the variation patterns obtained through numerical simulation.Third,we devise the location and dynamic control strategy for the cooling equipment based on the prediction models.The results of field application show that the heat resistance and cooling linkage method comply with the safety requirement throughout the entire mining cycle while effectively reducing energy consumption.The ambient temperature is maintained below 30℃,resulting in the energy saving of 10%during the high-temperature period and over 50%during the low-temperature period.These findings serve as a valuable reference for managing heat damage in high-temperature working faces.
文摘This paper studies the time-dependent analysis of an M/M/1 queueing model with single,multiple working vacation,balking and vacation interruptions.Whenever the system becomes empty,the server commences working vacation.During the working vacation period,if the queue length reaches a positive threshold value‘k’,the working vacation of the server is interrupted and it immediately starts the service in an exhaustive manner.During working vacations,the customers become discouraged due to the slow service and possess balking behavior.The transient system size probabilities of the proposed model are derived explicitly using the method of generating function and continued fraction.The performance indices such as average and variance of system size are also obtained.Further,numerical simulations are presented to analyze the impact of system parameters.
文摘采用多元回归分析原理及模型,结合回采工作面瓦斯涌出量的实测数据,利用SPSS(Statistical Product and Service Solutions)软件对回采工作面瓦斯涌出量的影响因素进行多元回归分析,建立了回归方程来预测回采工作面瓦斯涌出量。结果表明,利用SPSS软件直接对影响回采工作面瓦斯涌出量的因素进行回归分析,避免了复杂的推导与计算,预测精度较高。
