The paper introduced complete sets of automatic equipment and technology used in thin seam coal face, and proposed the comprehensive mechanization and automation of safe and high efficiency mining models based on the ...The paper introduced complete sets of automatic equipment and technology used in thin seam coal face, and proposed the comprehensive mechanization and automation of safe and high efficiency mining models based on the thin seam drum shearer. The key technology of short length and high power thin seam drum shearer, and new type roof support with big extension ratio and plate canopy were introduced. The new research achievement on automatic control system of complete sets of equipment for the thin seam coal, which composed of electronic-hydraulic system, compact thin seam roof supports, high effective shearer with intelligent control system, and characterized by automatical follow-up and remote control technology, was described in this paper..展开更多
Background of the development and achievement on sets equipment technologies for coal mine longwall face in China was reviewed initially. On the theoretical side, a coupling model of hydraulic support and surrounding ...Background of the development and achievement on sets equipment technologies for coal mine longwall face in China was reviewed initially. On the theoretical side, a coupling model of hydraulic support and surrounding rock, support pa- rameters optimization and threedimensional （3D） dynamic design method were presented. On the practical side, this paper out lined some of practical issues and discussed some relative methods and technologies. In thin seam coal longwall mining, how to lower equipment height is the first problem that should be solved. Roof pressure regularity, control of rooffall and collapse, and hydraulic support stability were investigated preferentially in 5-7 m coal seam longwall mining. The application of equip- ment for longwall mining with 5-7 m cutting height in China was concluded. The characteristics of full-mechanized top coal caving for extra thick seam coal were presented. The automation of top-caving hydraulic support and relevant equipment have achieved important breakthrough. At the end of this paper, further development of China＇s coal industry and longwall mining technologies and equipment were prospected in brief. This paper gives readers a comprehensive understanding of China＇s coal mine longwall face equipment technologies. It will give help to other countries on its coal mining development.展开更多
The goal of the paper is to conduct an exploratory review and analyses of the dynamics of the pandemic focusing on two themes:pandemic morbidity and vulnerable populations.Method:Review of literature,anecdotal evidenc...The goal of the paper is to conduct an exploratory review and analyses of the dynamics of the pandemic focusing on two themes:pandemic morbidity and vulnerable populations.Method:Review of literature,anecdotal evidence,and reports on the morbidity of COVID-19;including scope of its devastating effects in selected countries.Findings:The devastating effects of the coronavirus are felt across different vulnerable populations.These include the elderly,front line workers,marginalized communities,visible minorities,and more.Inadequate and sometimes conflicting remarks by“experts”have only contributed in exacerbating the confusion in the general population.However,compassion and empathy from different communities have had positive effects on mitigating some of the health outcomes like mental health and other health-related effects of the pandemic.Institutional support needs to be strengthened,especially with regard to individual risks and supply chain coordination:personal protection equipment(PPE),masks,swabs,reagents,etc.The challenge in Africa is especially daunting,because of limited and inadequate financial resources and infrastructure,as confirmed by the health budget allocations as a percentage of their respective GDP(gross domestic product).Discussion:The effects of the COVID-19 are producing unprecedented and catastrophic outcomes in many countries.These have been exacerbated by the level of unpreparedness and inadequate degrees of prevention and intervention strategies.With a few exceptions,the common and current intervention approach is driven by many unknowns including compilation of relevant reliable and compelling data sets.Vulnerable communities continue to suffer most:a situation that is highlighted in this essay as one attempt to remind institutions of their duty to provide appropriate support,including compassion and empathy to these populations.The repercussions of no or inadequate action are numerous,significant,and mind-boggling with unpredictable future outcomes and possible dire consequences.T展开更多
基金Supported by the National Natural Science Foundation of China （50375026, 50375028） the National High-tech R＆D Program of China （863 Program） （2012AA06A407）
文摘The paper introduced complete sets of automatic equipment and technology used in thin seam coal face, and proposed the comprehensive mechanization and automation of safe and high efficiency mining models based on the thin seam drum shearer. The key technology of short length and high power thin seam drum shearer, and new type roof support with big extension ratio and plate canopy were introduced. The new research achievement on automatic control system of complete sets of equipment for the thin seam coal, which composed of electronic-hydraulic system, compact thin seam roof supports, high effective shearer with intelligent control system, and characterized by automatical follow-up and remote control technology, was described in this paper..
文摘Background of the development and achievement on sets equipment technologies for coal mine longwall face in China was reviewed initially. On the theoretical side, a coupling model of hydraulic support and surrounding rock, support pa- rameters optimization and threedimensional （3D） dynamic design method were presented. On the practical side, this paper out lined some of practical issues and discussed some relative methods and technologies. In thin seam coal longwall mining, how to lower equipment height is the first problem that should be solved. Roof pressure regularity, control of rooffall and collapse, and hydraulic support stability were investigated preferentially in 5-7 m coal seam longwall mining. The application of equip- ment for longwall mining with 5-7 m cutting height in China was concluded. The characteristics of full-mechanized top coal caving for extra thick seam coal were presented. The automation of top-caving hydraulic support and relevant equipment have achieved important breakthrough. At the end of this paper, further development of China＇s coal industry and longwall mining technologies and equipment were prospected in brief. This paper gives readers a comprehensive understanding of China＇s coal mine longwall face equipment technologies. It will give help to other countries on its coal mining development.
文摘The goal of the paper is to conduct an exploratory review and analyses of the dynamics of the pandemic focusing on two themes:pandemic morbidity and vulnerable populations.Method:Review of literature,anecdotal evidence,and reports on the morbidity of COVID-19;including scope of its devastating effects in selected countries.Findings:The devastating effects of the coronavirus are felt across different vulnerable populations.These include the elderly,front line workers,marginalized communities,visible minorities,and more.Inadequate and sometimes conflicting remarks by“experts”have only contributed in exacerbating the confusion in the general population.However,compassion and empathy from different communities have had positive effects on mitigating some of the health outcomes like mental health and other health-related effects of the pandemic.Institutional support needs to be strengthened,especially with regard to individual risks and supply chain coordination:personal protection equipment(PPE),masks,swabs,reagents,etc.The challenge in Africa is especially daunting,because of limited and inadequate financial resources and infrastructure,as confirmed by the health budget allocations as a percentage of their respective GDP(gross domestic product).Discussion:The effects of the COVID-19 are producing unprecedented and catastrophic outcomes in many countries.These have been exacerbated by the level of unpreparedness and inadequate degrees of prevention and intervention strategies.With a few exceptions,the common and current intervention approach is driven by many unknowns including compilation of relevant reliable and compelling data sets.Vulnerable communities continue to suffer most:a situation that is highlighted in this essay as one attempt to remind institutions of their duty to provide appropriate support,including compassion and empathy to these populations.The repercussions of no or inadequate action are numerous,significant,and mind-boggling with unpredictable future outcomes and possible dire consequences.T
