Targeting the problem of large amounts of gas emission from the goaf of the No.14201 working face in the Shaqu coal mine of Huajin Coking Coal Co. Ltd., we used a negative exponential function to describe the attenuat...Targeting the problem of large amounts of gas emission from the goaf of the No.14201 working face in the Shaqu coal mine of Huajin Coking Coal Co. Ltd., we used a negative exponential function to describe the attenuation process of gas emission in goaf (the stable source) based on the principle of field flow. Equations of two-component flow (gas and air) and seep- age-diffusion in a heterogeneous goaf flow field are solved by means of numerical simulation and fluid mechanics principles of air movement and gas distribution during gas emission from goaf. The results indicate that the air diversion volume has a negative, exponential relation with the volume of gas emitted from goaf to the working face and is clearly inversely related to gas concentra- tion. We calculated the minimum amount of air diversion and distributed air volume in the tailing roadway required for safe pro- duction.展开更多
Given the problem of harmful gas discharge in unsealing coal mining faces, we numerically simulated the process of change of gas flows and movements, We have pointed out that, at the moment of unsealing a closed stope...Given the problem of harmful gas discharge in unsealing coal mining faces, we numerically simulated the process of change of gas flows and movements, We have pointed out that, at the moment of unsealing a closed stope, the gas discharge is naturally divided into two parts, i.e., the discharge of gas in the working face and that in the goaf, because of the difference in the spatial medium. The absolute volume of gas discharged has a tendency to decrease from its initial peak value to a final stable value. The rate of decrease and the time needed to reach a stable discharge are related to the scale of the mining stope. The discharge of gas from the working face is closely related to the amount of air distributed in the air return way. The most important thing in unsealing a stope is to have the initial peak volume of gas discharged well under control. A commonly used method in solving this problem is at first to use a small amount of air and then increasing it gradually. Our study shows that, by extracting gas from the upper corner, we can use a large volume of air at first in order to shorten considerably the discharge time and improve efficiency, thereby making mining, activitv safer.展开更多
EVs （electric vehicles） have been widely accepted as a promising solution for reducing oil consumption, air pollution and greenhouse gas emission. The number of EVs is growing very fast over the years. However, the ...EVs （electric vehicles） have been widely accepted as a promising solution for reducing oil consumption, air pollution and greenhouse gas emission. The number of EVs is growing very fast over the years. However, the high adoption of EVs will impose a burden on the power system, especially for neighborhood level network. In this paper, we propose a mixed control framework for EV charging scheduling to mitigate its impact on the power network. A metric for modeling customer＇s satisfaction is also proposed to compare the user satisfaction for different algorithms. The impacts of the proposed algorithms on EV charging cost, EV penetration and peak power reduction are evaluated with real data for a neighborhood level network. The simulation results demonstrate the effectiveness of the proposed algorithms.展开更多
Nowadays, cities are the main living environment of human beings. Rapid urbanization is associated with a variety of issues： population explosion, urban heat island effect, greenhouse gases emissions, energy crisis, ...Nowadays, cities are the main living environment of human beings. Rapid urbanization is associated with a variety of issues： population explosion, urban heat island effect, greenhouse gases emissions, energy crisis, climate change and so on. To deal with the challenges from the huge energy consumption and GHGs （greenhouse gases） emission, more and more attention has been paid to low carbon eco-city in China. In this research, the whole process is linked by low carbon eco-city development. High-resolution thermal IR （infrared） satellite remote-sensing is introduced to land use and urban heat island monitoring to meet the requirement of higher accuracy. GIS （geo-information science） technology provides a framework for collecting, processing, managing, analyzing and sharing spatial and temporal data. It has been used in spatial and temporal database management and analysis in low carbon eco-city study. The integrated geo-information system proposed in this research, which will be introduced to various government agencies in China, could enrich the concepts and means for the construction of low carbon eco^city.展开更多
To study effect of C2H2 and change of headspace gas on N2O emission, denitrification, as well as CO2emission, slumes of an agricultural soil were anaerobically incubated for 7 da3’s at 25 ℃. Both N2O reduction and C...To study effect of C2H2 and change of headspace gas on N2O emission, denitrification, as well as CO2emission, slumes of an agricultural soil were anaerobically incubated for 7 da3’s at 25 ℃. Both N2O reduction and CO2 emissions were inhibited by the addition of 100 mL L-1 of C2H2. However, the inhibition to CO2 emission was alleviated by the replacement of headspace gas, and the N2O emission was enhanced by the replacement. Acetylene disappeared evidently from the soil slumes during the incubation. Consequently results obtained from the traditional C2H2 blocking technique for determination of denitrification rate, especially in a long-time incubation, should be explained with care because of its side effect existing in the incubation environments without change of headspace gas. To reduce the possible side effect on the processes other than denitrification, it is suggested that headspace gas should be replaced several times during a long-time incubation.展开更多
The paper investigates the dynamics of a new multiple bipolar multiple Dielectric Barrier Discharges(DBD)actuator using in large-scale flow control.Particle image velocimetry experiments are performed to characteristi...The paper investigates the dynamics of a new multiple bipolar multiple Dielectric Barrier Discharges(DBD)actuator using in large-scale flow control.Particle image velocimetry experiments are performed to characteristic the effectiveness of the multiple bipolar DBD plasma actuator.The results show that the mutual interaction between the electrodes,one major disadvantage of traditional DBD characterized by reverse discharge can be entirely avoided,and a constantly accelerating electric wind velocity can be obtained by using the new multiple bipolar DBD plasma actuator.展开更多
基金Project 50574038 supported by the National Natural Science Foundation of China
文摘Targeting the problem of large amounts of gas emission from the goaf of the No.14201 working face in the Shaqu coal mine of Huajin Coking Coal Co. Ltd., we used a negative exponential function to describe the attenuation process of gas emission in goaf (the stable source) based on the principle of field flow. Equations of two-component flow (gas and air) and seep- age-diffusion in a heterogeneous goaf flow field are solved by means of numerical simulation and fluid mechanics principles of air movement and gas distribution during gas emission from goaf. The results indicate that the air diversion volume has a negative, exponential relation with the volume of gas emitted from goaf to the working face and is clearly inversely related to gas concentra- tion. We calculated the minimum amount of air diversion and distributed air volume in the tailing roadway required for safe pro- duction.
基金Project 50574038 supported by the National Natural Science Foundation of Chinathe Scientific Research Foundation of Liaoning Technical University (No.2004-241)
文摘Given the problem of harmful gas discharge in unsealing coal mining faces, we numerically simulated the process of change of gas flows and movements, We have pointed out that, at the moment of unsealing a closed stope, the gas discharge is naturally divided into two parts, i.e., the discharge of gas in the working face and that in the goaf, because of the difference in the spatial medium. The absolute volume of gas discharged has a tendency to decrease from its initial peak value to a final stable value. The rate of decrease and the time needed to reach a stable discharge are related to the scale of the mining stope. The discharge of gas from the working face is closely related to the amount of air distributed in the air return way. The most important thing in unsealing a stope is to have the initial peak volume of gas discharged well under control. A commonly used method in solving this problem is at first to use a small amount of air and then increasing it gradually. Our study shows that, by extracting gas from the upper corner, we can use a large volume of air at first in order to shorten considerably the discharge time and improve efficiency, thereby making mining, activitv safer.
文摘EVs （electric vehicles） have been widely accepted as a promising solution for reducing oil consumption, air pollution and greenhouse gas emission. The number of EVs is growing very fast over the years. However, the high adoption of EVs will impose a burden on the power system, especially for neighborhood level network. In this paper, we propose a mixed control framework for EV charging scheduling to mitigate its impact on the power network. A metric for modeling customer＇s satisfaction is also proposed to compare the user satisfaction for different algorithms. The impacts of the proposed algorithms on EV charging cost, EV penetration and peak power reduction are evaluated with real data for a neighborhood level network. The simulation results demonstrate the effectiveness of the proposed algorithms.
文摘Nowadays, cities are the main living environment of human beings. Rapid urbanization is associated with a variety of issues： population explosion, urban heat island effect, greenhouse gases emissions, energy crisis, climate change and so on. To deal with the challenges from the huge energy consumption and GHGs （greenhouse gases） emission, more and more attention has been paid to low carbon eco-city in China. In this research, the whole process is linked by low carbon eco-city development. High-resolution thermal IR （infrared） satellite remote-sensing is introduced to land use and urban heat island monitoring to meet the requirement of higher accuracy. GIS （geo-information science） technology provides a framework for collecting, processing, managing, analyzing and sharing spatial and temporal data. It has been used in spatial and temporal database management and analysis in low carbon eco-city study. The integrated geo-information system proposed in this research, which will be introduced to various government agencies in China, could enrich the concepts and means for the construction of low carbon eco^city.
文摘To study effect of C2H2 and change of headspace gas on N2O emission, denitrification, as well as CO2emission, slumes of an agricultural soil were anaerobically incubated for 7 da3’s at 25 ℃. Both N2O reduction and CO2 emissions were inhibited by the addition of 100 mL L-1 of C2H2. However, the inhibition to CO2 emission was alleviated by the replacement of headspace gas, and the N2O emission was enhanced by the replacement. Acetylene disappeared evidently from the soil slumes during the incubation. Consequently results obtained from the traditional C2H2 blocking technique for determination of denitrification rate, especially in a long-time incubation, should be explained with care because of its side effect existing in the incubation environments without change of headspace gas. To reduce the possible side effect on the processes other than denitrification, it is suggested that headspace gas should be replaced several times during a long-time incubation.
文摘The paper investigates the dynamics of a new multiple bipolar multiple Dielectric Barrier Discharges(DBD)actuator using in large-scale flow control.Particle image velocimetry experiments are performed to characteristic the effectiveness of the multiple bipolar DBD plasma actuator.The results show that the mutual interaction between the electrodes,one major disadvantage of traditional DBD characterized by reverse discharge can be entirely avoided,and a constantly accelerating electric wind velocity can be obtained by using the new multiple bipolar DBD plasma actuator.
