Surface drilling was performed at the Luling Coal Mine,in Huaibei,to shorten the period required for gas draining.The experimental study was designed to reduce the cost of gas control by efficiently draining gas from ...Surface drilling was performed at the Luling Coal Mine,in Huaibei,to shorten the period required for gas draining.The experimental study was designed to reduce the cost of gas control by efficiently draining gas from the upper protected layer.The structural arraignment and technical principles of pressure relief via surface drilling are discussed.Results from the trial showed that gas drained from the surface system over a period of 10 months.The total amount of collected gas was 248.4 million m^3.The gas draining occurred in three stages：a growth period;a period of maximum gas production;and an attenuation period.The period of maximum gas production lasted for 4 months.During this time the methane concentration ranged from 60%to 90%and the average draining rate was 10.6 m^3/min.Combined with other methods of draining it was possible to drain 70.6%of the gas from middle coal seam groups.The amount of residual gas dropped to 5.2 m^3/ton,and the pressure of the residual gas fell to 0.53 MPa, thereby eliminating the outburst danger in the middle coal seam groups.The factors affecting pressure relief gas draining by surface drilling were analysed.展开更多
Automotive surface coating manufacturing is one of the most sophisticated and expensive steps in automotive assembly. This step involves generating multiple thin layers of polymeric coatings on the vehicle surface thr...Automotive surface coating manufacturing is one of the most sophisticated and expensive steps in automotive assembly. This step involves generating multiple thin layers of polymeric coatings on the vehicle surface through paint spray and curing in a multistage, dynamically changing environment. Traditionally, the quality control is solely post-process inspection based, and process operational adjustment is only experience based, thus the manufacturing may not be （highly） sustainable. In this article, a multiscale system modeling and analysis methodology is introduced for achieving a sustainable application of polymeric materials through paint spray and film curing in automotive surface coating manufacturing. By this methodology, the correlations among paint material, application processes and coating performance can be identified. The model-based analysis allows a comprehensive and deep study of the dynamic behaviors of the material, process, and product in a wide spectrum of length and time. Case studies illustrate the efficacy of the methodology for sustainable manufacturing.展开更多
基金supported by the Key Project of the Natural Science Foundation of China(No.70533050 and 51004106)the Fundamental Research Funds for the Central Universities (No.2010QNB02)
文摘Surface drilling was performed at the Luling Coal Mine,in Huaibei,to shorten the period required for gas draining.The experimental study was designed to reduce the cost of gas control by efficiently draining gas from the upper protected layer.The structural arraignment and technical principles of pressure relief via surface drilling are discussed.Results from the trial showed that gas drained from the surface system over a period of 10 months.The total amount of collected gas was 248.4 million m^3.The gas draining occurred in three stages：a growth period;a period of maximum gas production;and an attenuation period.The period of maximum gas production lasted for 4 months.During this time the methane concentration ranged from 60%to 90%and the average draining rate was 10.6 m^3/min.Combined with other methods of draining it was possible to drain 70.6%of the gas from middle coal seam groups.The amount of residual gas dropped to 5.2 m^3/ton,and the pressure of the residual gas fell to 0.53 MPa, thereby eliminating the outburst danger in the middle coal seam groups.The factors affecting pressure relief gas draining by surface drilling were analysed.
基金Supported in part by US NSF (CBET 0647113 and 0730383, CMMI 0700178, and DUE 0736739)the Institute of Manufacturing Research of Wayne State University.
文摘Automotive surface coating manufacturing is one of the most sophisticated and expensive steps in automotive assembly. This step involves generating multiple thin layers of polymeric coatings on the vehicle surface through paint spray and curing in a multistage, dynamically changing environment. Traditionally, the quality control is solely post-process inspection based, and process operational adjustment is only experience based, thus the manufacturing may not be （highly） sustainable. In this article, a multiscale system modeling and analysis methodology is introduced for achieving a sustainable application of polymeric materials through paint spray and film curing in automotive surface coating manufacturing. By this methodology, the correlations among paint material, application processes and coating performance can be identified. The model-based analysis allows a comprehensive and deep study of the dynamic behaviors of the material, process, and product in a wide spectrum of length and time. Case studies illustrate the efficacy of the methodology for sustainable manufacturing.
