The bio-clogging using bacteria can be an eco-friendly and sustainable alternative to conventional grouting methods for seepage control.However,it remains unclear to date how the dilute concentration of bacterium and ...The bio-clogging using bacteria can be an eco-friendly and sustainable alternative to conventional grouting methods for seepage control.However,it remains unclear to date how the dilute concentration of bacterium and medium during field installation can affect the setting time of bacterium and its correlation with permeability reduction.In this study,the setting time of bacterium and its effectiveness in permeability reduction were addressed through experimental and theoretical investigations.A series of sand column was cultivated using different concentrations of Leuconostoc mesenteroides and culture medium.The distribution and composition of the bacterial product(i.e.dextran)were observed by refractometer,scanning electron microscope(SEM),and energy dispersive X-ray spectroscopy(EDS).Soil permeability was recorded using a constant head test.The results revealed that bacterium was effective to produce dextran at the setting time of about 5 d after installation.This dextran can reduce the permeability of bio-mediated soil by two orders of magnitude,even without culture medium supply.In general,the dextran production decreased proportionally with increase of bacterium and medium concentration.However,at 50%bacterium and medium concentration by weight,it still has a significant influence on permeability reduction with similar setting time,compared to 100%concentration.展开更多
In the paper, the reciprocal theorem is applied to research on the bending of set square with one free oblique edge and two clamped edges under a concentrated load acting at any point. This method is simpler and general.
The epithermal ore concentrated area is located in Southwestern China. We systematically study the regional geological characteristics such as the basement of Proterozoic, the capping bed, Moho, geothermal feature and...The epithermal ore concentrated area is located in Southwestern China. We systematically study the regional geological characteristics such as the basement of Proterozoic, the capping bed, Moho, geothermal feature and tectonics, and discuss the relationship between distributed characteristics of the epithermal ore deposits and ore control factors in this paper. It is concluded that the conditions, under which the epithermal ore deposits form, are huge thick basement of Proterozoic, long time and wide scope developed capping bed and weak magmatic activity. The basement of Proterozoic that enriches volcanic matters and carbon and the carbonaceous bearing and paleo pool bearing capping bed provides main ore source. The large and deep faults and paleopool accordance with gravity anomaly gradient control the distribution of epithermal ore deposits. The lithologic assembles of microclastic rocks and carbonate rocks in the capping bed provide spaces of ore precipitation and create conditions of ore precipitation. The coincidence of many geological factors above forms the epithermal ore concentrated area.展开更多
A black hole is essentially a relativistic as well as a quantum object. Therefore the information paradox of black holes is a consequence of the clash between these two most fundamental theories of modern physics. It ...A black hole is essentially a relativistic as well as a quantum object. Therefore the information paradox of black holes is a consequence of the clash between these two most fundamental theories of modern physics. It is logical to conclude that a resolution of the problem requires some form of a quantum gravity theory. The present work proposes such a resolution using set theory and pointless spacetime geometry.展开更多
煤矿抽采瓦斯主要成分为甲烷,直接排空严重污染环境。甲烷也是一种热值高、无污染的清洁能源,为了实现变“害”为“宝”,开展了小西煤矿抽采瓦斯发电利用工程设计研究。首先,根据小西煤矿抽采瓦斯浓度低于30%确立了发电站为低浓度瓦斯...煤矿抽采瓦斯主要成分为甲烷,直接排空严重污染环境。甲烷也是一种热值高、无污染的清洁能源,为了实现变“害”为“宝”,开展了小西煤矿抽采瓦斯发电利用工程设计研究。首先,根据小西煤矿抽采瓦斯浓度低于30%确立了发电站为低浓度瓦斯发电站,并设计了发电站的工艺流程,接着开展了气源接口系统、掺混装置、低浓度瓦斯输送安全保障系统、脱水系统设计。结合抽采瓦斯参数及不同类型发电机组特点,选择发电机组为燃气内燃机,并根据抽采瓦斯浓度及流量,设计发电机组装机容量为8×1 000 k W。最后根据周边电网情况,确立了发电机组输出10.5 k V电经升压变压器升至35 k V后在小西煤矿35 k V变电站并网。展开更多
基金This work is supported by King Mongkut’s Institute of Technology Ladkrabang(Grant No.2563-02-01-014).
文摘The bio-clogging using bacteria can be an eco-friendly and sustainable alternative to conventional grouting methods for seepage control.However,it remains unclear to date how the dilute concentration of bacterium and medium during field installation can affect the setting time of bacterium and its correlation with permeability reduction.In this study,the setting time of bacterium and its effectiveness in permeability reduction were addressed through experimental and theoretical investigations.A series of sand column was cultivated using different concentrations of Leuconostoc mesenteroides and culture medium.The distribution and composition of the bacterial product(i.e.dextran)were observed by refractometer,scanning electron microscope(SEM),and energy dispersive X-ray spectroscopy(EDS).Soil permeability was recorded using a constant head test.The results revealed that bacterium was effective to produce dextran at the setting time of about 5 d after installation.This dextran can reduce the permeability of bio-mediated soil by two orders of magnitude,even without culture medium supply.In general,the dextran production decreased proportionally with increase of bacterium and medium concentration.However,at 50%bacterium and medium concentration by weight,it still has a significant influence on permeability reduction with similar setting time,compared to 100%concentration.
文摘In the paper, the reciprocal theorem is applied to research on the bending of set square with one free oblique edge and two clamped edges under a concentrated load acting at any point. This method is simpler and general.
文摘The epithermal ore concentrated area is located in Southwestern China. We systematically study the regional geological characteristics such as the basement of Proterozoic, the capping bed, Moho, geothermal feature and tectonics, and discuss the relationship between distributed characteristics of the epithermal ore deposits and ore control factors in this paper. It is concluded that the conditions, under which the epithermal ore deposits form, are huge thick basement of Proterozoic, long time and wide scope developed capping bed and weak magmatic activity. The basement of Proterozoic that enriches volcanic matters and carbon and the carbonaceous bearing and paleo pool bearing capping bed provides main ore source. The large and deep faults and paleopool accordance with gravity anomaly gradient control the distribution of epithermal ore deposits. The lithologic assembles of microclastic rocks and carbonate rocks in the capping bed provide spaces of ore precipitation and create conditions of ore precipitation. The coincidence of many geological factors above forms the epithermal ore concentrated area.
文摘A black hole is essentially a relativistic as well as a quantum object. Therefore the information paradox of black holes is a consequence of the clash between these two most fundamental theories of modern physics. It is logical to conclude that a resolution of the problem requires some form of a quantum gravity theory. The present work proposes such a resolution using set theory and pointless spacetime geometry.
文摘煤矿抽采瓦斯主要成分为甲烷,直接排空严重污染环境。甲烷也是一种热值高、无污染的清洁能源,为了实现变“害”为“宝”,开展了小西煤矿抽采瓦斯发电利用工程设计研究。首先,根据小西煤矿抽采瓦斯浓度低于30%确立了发电站为低浓度瓦斯发电站,并设计了发电站的工艺流程,接着开展了气源接口系统、掺混装置、低浓度瓦斯输送安全保障系统、脱水系统设计。结合抽采瓦斯参数及不同类型发电机组特点,选择发电机组为燃气内燃机,并根据抽采瓦斯浓度及流量,设计发电机组装机容量为8×1 000 k W。最后根据周边电网情况,确立了发电机组输出10.5 k V电经升压变压器升至35 k V后在小西煤矿35 k V变电站并网。
