The objective of the present study is to characterize the production of hydrogen with a sorptionenhanced steam-methane reaction process using Ca(OH)2 as the CO2 adsorbent. Theoretical equilibrium compositions at diffe...The objective of the present study is to characterize the production of hydrogen with a sorptionenhanced steam-methane reaction process using Ca(OH)2 as the CO2 adsorbent. Theoretical equilibrium compositions at different operation conditions were calculated using an iterative method. It was found that with Ca(OH)2 as the CO2 sorbent, the concentration of CO2 adsorption was reduced in the product stream, that gave rise to higher methane conversion and higher H2 concentration. An experimental setup was built to test the theoretical calculation. The effects of sorbents and the particle size of Ca(OH)2 on the concentration of CO2 and H2 were investigated in detail. Results showed that the reactor packed with catalyst and Ca(OH)2 particles produced H2 concentration of 94%. It was nearly 96% of the theoretical equilibrium limit, much higher than H2 equilibrium concentration of 67.5% without CO2 sorption under the same conditions of 500℃, 0.2 MPa pressure and a steam-to-methane ratio 6. In addition, the residual mole fraction of CO2 was less than 0.001.展开更多
Cavity resonance noise of passenger car tires is generated by interacting excitation between a tire structure and the fill gas (air), and generally lies in a frequency range of 200?250 Hz. As such, this noise is stron...Cavity resonance noise of passenger car tires is generated by interacting excitation between a tire structure and the fill gas (air), and generally lies in a frequency range of 200?250 Hz. As such, this noise is strongly perceived and may be a serious source of driver annoyance. Thus, many studies regarding the cavity noise mechanism and its reduction have already been conducted. In this work, a vibro-acoustic coupled analysis was conducted between a tire structure and air cavity. Using this analysis, we can more accurately simulate the tire noise performance in the region of the cavity resonance frequency. An analysis of the effects of variation of tire contour design factors was conducted, using design-of-experiments methods. Finally, a multi-objective optimization was performed using in-house codes to reduce the cavity noise level while minimizing the loss of other performances, such as diminished ride comfort and handling caused by the variations of contour. As a result of this optimization, an optimized contour shape was derived, which satisfied the multi-objective performances.展开更多
According to IPCC （Intergovemmental Panel on Climate Change） Fourth Report, carbon dioxide emissions from the combustion of fossil fuels have been identified as the major contributor to global warming and climate ch...According to IPCC （Intergovemmental Panel on Climate Change） Fourth Report, carbon dioxide emissions from the combustion of fossil fuels have been identified as the major contributor to global warming and climate change. One of the new approaches for capturing carbon dioxide and subsequently lowering the emissions is based on gas hydrate crystallization. Gas hydrates have a large capacity for the storage of gases which also resemble an attractive method for gas filtration. The basis of the separation is the selective partition of the target component between the hydrate phase and the gaseous phase. It is expected that carbon dioxide is preferentially encaged into the hydrate crystal phase compared to the other components. In the present paper, after a comparison of gas hydrates with existing capture technologies, a novel apparatus for gas hydrate production is illustrated and results of a first set of experimental applications of the reactor for CO2 hydrate formation and separation are presented. In particular, the effects of two different promoters were investigated. Results show that the reactor allows a good level of temperature control, resulting in rapid hydrate formation and mild operating conditions. Results are a basis for setting up a procedure for CO2 separation and capture.展开更多
This paper presents an advanced and integrated research approach to longwall mining-induced strata move- ment, stress changes, fractures, and gas flow dynamics with actual examples of its application from recent studi...This paper presents an advanced and integrated research approach to longwall mining-induced strata move- ment, stress changes, fractures, and gas flow dynamics with actual examples of its application from recent studies for coextraction of coal and methane development at Huainan Mining Group in China, in a deep and multi-seam mining environment. The advanced approach takes advantage of the latest techniques in Australia for mine scale geotechnical characterisation, field measurement, monitoring and numerical modelling. Key techniques described in this paper include coal mine site 3D geotechnical characterisation methods, surface deep downhole multi-point extensometers and piezometers for overburden displacement and pore pressure measurements during mining, tracer gas tests for goal gas flow patterns, and advanced numerical modelling codes for coupled coal mine strata, water and gas simulations, and longwall goaf gas ttow investigations. This integrated approach has resulted in significant insights into the complex dynamic imeraction between strata, groundwater, and gas during mining at Huainan Mining Group in recent years. Based on the lindings from the extensive field monitoring and numerical modelling studies, a three-dimensional annular-shaped over-lying zone along the perimeter of the longwall panel was identified for optimal methane drainage during mining.展开更多
Objective: To investigate the correlations of vascular endothelial growth factor (VEGF)-positive tumor angiogenesis and the quantifiable parameters of blood flow pattern derived with dynamic CT in solitary bronchogeni...Objective: To investigate the correlations of vascular endothelial growth factor (VEGF)-positive tumor angiogenesis and the quantifiable parameters of blood flow pattern derived with dynamic CT in solitary bronchogenic adenocarcinoma. Methods: 30 patients with VEGF-positive bronchogenic adenocarcinomas (diameter ≤ 4 cm) underwent multi-location dynamic contrast material-enhanced (nonionic contrast material was administrated via the antecubital vein at a rate of 4 mL/sec by using an autoinjector) serial CT. The quantifiable parameters (Perfusion, peak height, ratio of peak height of the bronchogenic adenocarcinoma to that of the aorta and mean transit time) of blood flow pattern derived with dynamic CT in solitary bronchogenic adenocarcinoma were compared with microvessel densities (MVDs) and VEGF expression by immunohistochemistry. Results: Peak height of VEGF-positive bronchogenic adenocarcinoma was 36.06 HU ± 13.57 HU, bronchogenic adenocarcinoma-to-aorta ratio 14.25% ± 4.92, and perfusion value 29.66 ± 5.60 mL/min/100 g , mean transit time 14.86 s ± 5.84 s, and MVD 70.15 ± 20.03. Each of peak height, ratio of peak height of the bronchogenic adenocarcinoma to that of the aorta and perfusion correlated positively with MVD (r = 0.781, P < 0.0001; r = 0.688, P < 0.0001; r = 0.716, P < 0.0001; respectively). No significant correlation was found between mean transit time and MVD (r = 0.260, P = 0.200 > 0.05). Conclusion: Perfusion, peak height and ratio of peak height of the bronchogenic adenocarcinoma to that of the aorta reflect MVD in VEGF-positive bronchogenic adenocarcinoma. Perfusion, peak height and ratio of peak height of the bronchogenic adenocarcinoma to that of the aorta derived with dynamic CT might be index for VEGF-related tumor angiogenesis in bronchogenic adenocarcinoma.展开更多
The gas cooperative control model combined local pressure-relief with regional pressure-reliet was estaonsnea, based on the theory of multi-parameters cooperative. For the status of high gas contents, high in-situ str...The gas cooperative control model combined local pressure-relief with regional pressure-reliet was estaonsnea, based on the theory of multi-parameters cooperative. For the status of high gas contents, high in-situ stress and low-permeability of Ji-15 seam of No.12 coal mine in Pingmei Group. The law of detonation wave propagation and ground-stress change distribution were simulated by means of the finite element analysis software. The technology of high-low-blasting, composed of high blasting（deep crossing hole controlled hydraulic blasting） and low blasting （special roadway deep hole controlled blasting） were developed. The research shows that around control hole produce maximum tension fracture failure, and result in directional and controlled Masting, when the distance between control hole and blasting hole is 1.2 m. The theory makes blasting force and hydraulic force advantage superimpose, which raises the effect of pressure relief and permeability enhancements compared with general blasting. High blasting influence radius and low blasting influence radius superimposed with each other, that prevents methane dynamic disaster. The result of type approval test shows that the technology can increase gas permeability as high as 22.7-36.2 ratio, decrease gas pressure from 2.85 MPa to 0.30 MPa, increase drilling influence radius to about 9 m. The technology realizes regional overall permeability improvement, that provides a new technical measure for methane dynamic disaster prevention.展开更多
文摘The objective of the present study is to characterize the production of hydrogen with a sorptionenhanced steam-methane reaction process using Ca(OH)2 as the CO2 adsorbent. Theoretical equilibrium compositions at different operation conditions were calculated using an iterative method. It was found that with Ca(OH)2 as the CO2 sorbent, the concentration of CO2 adsorption was reduced in the product stream, that gave rise to higher methane conversion and higher H2 concentration. An experimental setup was built to test the theoretical calculation. The effects of sorbents and the particle size of Ca(OH)2 on the concentration of CO2 and H2 were investigated in detail. Results showed that the reactor packed with catalyst and Ca(OH)2 particles produced H2 concentration of 94%. It was nearly 96% of the theoretical equilibrium limit, much higher than H2 equilibrium concentration of 67.5% without CO2 sorption under the same conditions of 500℃, 0.2 MPa pressure and a steam-to-methane ratio 6. In addition, the residual mole fraction of CO2 was less than 0.001.
文摘Cavity resonance noise of passenger car tires is generated by interacting excitation between a tire structure and the fill gas (air), and generally lies in a frequency range of 200?250 Hz. As such, this noise is strongly perceived and may be a serious source of driver annoyance. Thus, many studies regarding the cavity noise mechanism and its reduction have already been conducted. In this work, a vibro-acoustic coupled analysis was conducted between a tire structure and air cavity. Using this analysis, we can more accurately simulate the tire noise performance in the region of the cavity resonance frequency. An analysis of the effects of variation of tire contour design factors was conducted, using design-of-experiments methods. Finally, a multi-objective optimization was performed using in-house codes to reduce the cavity noise level while minimizing the loss of other performances, such as diminished ride comfort and handling caused by the variations of contour. As a result of this optimization, an optimized contour shape was derived, which satisfied the multi-objective performances.
文摘According to IPCC （Intergovemmental Panel on Climate Change） Fourth Report, carbon dioxide emissions from the combustion of fossil fuels have been identified as the major contributor to global warming and climate change. One of the new approaches for capturing carbon dioxide and subsequently lowering the emissions is based on gas hydrate crystallization. Gas hydrates have a large capacity for the storage of gases which also resemble an attractive method for gas filtration. The basis of the separation is the selective partition of the target component between the hydrate phase and the gaseous phase. It is expected that carbon dioxide is preferentially encaged into the hydrate crystal phase compared to the other components. In the present paper, after a comparison of gas hydrates with existing capture technologies, a novel apparatus for gas hydrate production is illustrated and results of a first set of experimental applications of the reactor for CO2 hydrate formation and separation are presented. In particular, the effects of two different promoters were investigated. Results show that the reactor allows a good level of temperature control, resulting in rapid hydrate formation and mild operating conditions. Results are a basis for setting up a procedure for CO2 separation and capture.
文摘This paper presents an advanced and integrated research approach to longwall mining-induced strata move- ment, stress changes, fractures, and gas flow dynamics with actual examples of its application from recent studies for coextraction of coal and methane development at Huainan Mining Group in China, in a deep and multi-seam mining environment. The advanced approach takes advantage of the latest techniques in Australia for mine scale geotechnical characterisation, field measurement, monitoring and numerical modelling. Key techniques described in this paper include coal mine site 3D geotechnical characterisation methods, surface deep downhole multi-point extensometers and piezometers for overburden displacement and pore pressure measurements during mining, tracer gas tests for goal gas flow patterns, and advanced numerical modelling codes for coupled coal mine strata, water and gas simulations, and longwall goaf gas ttow investigations. This integrated approach has resulted in significant insights into the complex dynamic imeraction between strata, groundwater, and gas during mining at Huainan Mining Group in recent years. Based on the lindings from the extensive field monitoring and numerical modelling studies, a three-dimensional annular-shaped over-lying zone along the perimeter of the longwall panel was identified for optimal methane drainage during mining.
文摘Objective: To investigate the correlations of vascular endothelial growth factor (VEGF)-positive tumor angiogenesis and the quantifiable parameters of blood flow pattern derived with dynamic CT in solitary bronchogenic adenocarcinoma. Methods: 30 patients with VEGF-positive bronchogenic adenocarcinomas (diameter ≤ 4 cm) underwent multi-location dynamic contrast material-enhanced (nonionic contrast material was administrated via the antecubital vein at a rate of 4 mL/sec by using an autoinjector) serial CT. The quantifiable parameters (Perfusion, peak height, ratio of peak height of the bronchogenic adenocarcinoma to that of the aorta and mean transit time) of blood flow pattern derived with dynamic CT in solitary bronchogenic adenocarcinoma were compared with microvessel densities (MVDs) and VEGF expression by immunohistochemistry. Results: Peak height of VEGF-positive bronchogenic adenocarcinoma was 36.06 HU ± 13.57 HU, bronchogenic adenocarcinoma-to-aorta ratio 14.25% ± 4.92, and perfusion value 29.66 ± 5.60 mL/min/100 g , mean transit time 14.86 s ± 5.84 s, and MVD 70.15 ± 20.03. Each of peak height, ratio of peak height of the bronchogenic adenocarcinoma to that of the aorta and perfusion correlated positively with MVD (r = 0.781, P < 0.0001; r = 0.688, P < 0.0001; r = 0.716, P < 0.0001; respectively). No significant correlation was found between mean transit time and MVD (r = 0.260, P = 0.200 > 0.05). Conclusion: Perfusion, peak height and ratio of peak height of the bronchogenic adenocarcinoma to that of the aorta reflect MVD in VEGF-positive bronchogenic adenocarcinoma. Perfusion, peak height and ratio of peak height of the bronchogenic adenocarcinoma to that of the aorta derived with dynamic CT might be index for VEGF-related tumor angiogenesis in bronchogenic adenocarcinoma.
基金Supported by the Major Project of Chinese National Program for Fundamental Research and Development （973） （2011CB201205） the Nature Science Foundation of China （50804048）
文摘The gas cooperative control model combined local pressure-relief with regional pressure-reliet was estaonsnea, based on the theory of multi-parameters cooperative. For the status of high gas contents, high in-situ stress and low-permeability of Ji-15 seam of No.12 coal mine in Pingmei Group. The law of detonation wave propagation and ground-stress change distribution were simulated by means of the finite element analysis software. The technology of high-low-blasting, composed of high blasting（deep crossing hole controlled hydraulic blasting） and low blasting （special roadway deep hole controlled blasting） were developed. The research shows that around control hole produce maximum tension fracture failure, and result in directional and controlled Masting, when the distance between control hole and blasting hole is 1.2 m. The theory makes blasting force and hydraulic force advantage superimpose, which raises the effect of pressure relief and permeability enhancements compared with general blasting. High blasting influence radius and low blasting influence radius superimposed with each other, that prevents methane dynamic disaster. The result of type approval test shows that the technology can increase gas permeability as high as 22.7-36.2 ratio, decrease gas pressure from 2.85 MPa to 0.30 MPa, increase drilling influence radius to about 9 m. The technology realizes regional overall permeability improvement, that provides a new technical measure for methane dynamic disaster prevention.
