Active protection of work area against explosion of dust-gas mixture

Potentially explosive atmosphere can occur not only in the production systems of the food,energy,chemical and petrochemical industries but also in the production processes of the mining industry.Gases,vapours,mists and dusts arise can escape in an uncontrolled way during production,processing,transportation and storage of flammable substances.In combination with oxygen,they create explosive atmospheres that,if ignited,lead to an explosion causing catastrophic damage to peopled lives and property.To protect against the results of hazardous dust-gas mixtures explosions in a confined work space,where employees can stay,various control and protection mechanisms are used in the form of an active explosion-proof system.The article presents the results of tests on an active system for limiting the effects of ignition of gas and/or dust based on a highly efficient explosion suppression system-equipped with an ignition detection system,high-pressure fire extinguisher and a power supply and trigger system.Smokeless powder was used as the explosive charge and sodium bicarbonate as the suppressive material.Tests of the effectiveness of the active explosion suppression system were carried out on two devices:a small-size dry dust collector and a zone extinguishing system adapted for direct explosion suppression in closed working spaces.In both cases,the explosion suppression process took place through the action of extinguishing powder blown out of the fire extinguisher after membrane perforation by compressed combustion products.

Selection of organic Rankine cycle working fluid based on unit-heat-exchange-area net power

To improve energy conversion efficiency, optimization of the working fluids in organic Rankine cycles(ORCs) was explored in the range of low-temperature heat sources. The concept of unit-heat-exchange-area(UHEA) net power, embodying the cost/performance ratio of an ORC system, was proposed as a new indicator to judge the suitability of ORC working fluids on a given condition. The heat exchange area was computed by an improved evaporator model without fixing the minimum temperature difference between working fluid and hot fluid, and the flow pattern transition during heat exchange was also taken into account. The maximum UHEA net powers obtained show that dry organic fluids are more suitable for ORCs than wet organic fluids to recover low-temperature heat. The organic fluid 1-butene is recommended if the inlet temperature of hot fluid is 353.15-363.15 K or443.15-453.15 K, heptane is more suitable at 373.15-423.15 K, and R245 ca is a good option at 483.15-503.15 K.

Ground stability of new surface buildings erected on site above worked-out area

The subsided area caused by mining is expanding gradually in coal mining areas. In order to occupy less or no farmland, many mining areas are constructing or intend to erect new buildings (structures) on the ground sites above the worked-out areas. The long-term safety of the new buildings is of great importance. This matter should be, therefore, handled with great care. Following an analysis of the different conditions of the worked-out areas, and the characteristics of the failure of different types of worked-out areas and their overlying strata, the cause for the occurrence of residual deformation of the surface above the worked-out area was explained. The techniques for (evaluating) the stability of ground site for erecting new buildings above worked-out area, and the technical measures for protecting such buildings were proposed. The ground stability evaluation techniques were introduced by reference to specific cases.

Working in Remote Areas Services are scarce in mountainous regions

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Factors Influencing Migrant Workers' Urban Labor Patterns: Willing Working Time in Urban Areas as the Mediator

China is witnessing a very complicated economic development environment.Migrant workers'working patterns will directly affect their income level and the realization of many economic and social development goals.This paper collects relevant data from three places:Shanghai,Lanzhou and Chengdu for empirical research whose results show that determinants of migrant worker's willing working time in urban areas mainly include the“income-consumption difference”,“urban-rural consumption difference”and their“urban income and expenditure uncertainty”.These factors directly affect their effective working time in the city,and determine their choice of choosing corresponding work patterns.From the significant differences of these factors,we can see that migrant workers in China is still struggling to solve their material needs under the pressure of livelihood,and less attention is paid to their spiritual needs and the pursuit of quality of life.

Christian Faith Rush in Rural Areas and Social Work Intervention

To make the public have rational knowledge of the Christian faith rush in rural areas and guide coordinated development of Christianity with the socialist society, we analyzed reasons and complex influence on rural social development from aspects of society and individual and attraction of Christianity by the Literature Analysis Method. In view of its negative effect, we put forward several countermeasures from the perspective of social work intervention, such as improving farmers' overall qualities, promoting effective implementation of social security system, and correcting believers' understanding of Christianity. Finally, we introduced situation of Christian faith in other countries and reference and directive significance to China.

Driving factors and the implications of work choices of rural laborers in ecologically vulnerable areas in North China

Using rural survey data for the year 2009,we provide evidence of work choices of rural laborers in ecologically vulnerable areas in North China,and model these choices as a function of characteristics of individuals,households,and land endowments.The findings reveal large differences between males and females,and between non-farm employment and part-time farming engagement Land scarcity is still an important driving factor in non-farming participation of rural laborers in the study area;and in the current case of land productivity and the total amount of land,there are still surplus rural labor forces in the study area.Diversification of livelihood reduces the pressure on land,thus facilitating ecosystem conservation.So,the paper concludes with the argument that establishing coordination mechanisms among non-farm employment of rural laborers,agricultural production,and restoration of ecosystems are essential for mitigating the conflicts of ecological security,agricultural production,and rural development in mis area.

软土地区基坑前排倾斜双排桩支护现场试验及工作机理

基坑倾斜桩支护大幅提高了无支撑支护结构的适用深度,具有造价低、施工便捷、绿色低碳、变形控制好等特点,然而目前研究多集中在单排倾斜桩,对前排倾斜双排桩支护的试验、理论与应用的研究均较少。针对前排倾斜双排桩支护基坑开展了现场试验,同时采用有限元方法分别从前排斜桩、桩顶连梁及桩间土体作用3个方面深入探究了前排倾斜双排桩支护的工作机理,进一步分析了直斜桩长度和排距对前排倾斜双排桩支护结构受力变形性能的影响。结果表明,相比传统竖直双排桩,前排倾斜双排桩支护结构的支护性能显著提升,前排斜桩主要发挥“斜撑”作用,连梁主要起到将直斜桩及冠梁连接成一个空间刚架的作用,桩间土体能够提高桩土摩阻力,进而有效减小前排倾斜双排桩变形。研究成果有助于前排倾斜双排桩的推广和应用。

地下大空间变工作区贴附送风空气分布特性

针对地下大空间环控系统能耗大以及实际中空调控制区改变的问题,在贴附送风的基础上提出适用地下大空间的变工作区贴附送风。采用数值模拟的方法,首先进行正交实验研究了等温工况下导流板与墙壁间的缝隙宽度、射流特征厚度、矩形柱跨度对流量比的影响程度大小,并通过量纲分析得出流量比q关于缝隙宽度与射流特征厚度之比x/δ_(0.5)间的关系式,即导流板的流量分配规律;其次将变工作区贴附送风与混合通风、柱壁贴附送风的空气分布特性进行了比较,研究结果显示,相比于另外两种送风方式,变工作区贴附送风可有效降低呼吸区的空气龄,并具有更好的节能效果。

2024年中央一号文件的突出亮点

2024年中央一号文件以习近平新时代中国特色社会主义思想为指导,为2024年乃至今后一段时期的“三农”工作进行了系统部署和具体安排,呈现了一系列突出亮点。即:凸显了贯彻中央经济工作会议精神和深化对“三农”工作的规律性认识,明确了学习运用“千万工程”经验引领乡村全面振兴的要求,重视运用战略思维和改革创新,统筹强化软政策引领与硬政策支撑作用,坚持守正创新,确保国家粮食安全有新招,确保不发生规模性返贫底线更明确措施更有力,强调以坚持“三个提升”为重点建设宜居宜业和美乡村。

由强省到强国:省级政府推进特色农业强国政策体系的异质性研究

农业强省是农业强国的有机组成部分,地方政府对农业强国战略的推进是农业强国建设的重要环节。农业强国的政策体系主要以政策背景、政策手段和政策目标三大要素来构成。其中,政策背景作为出发点,分别从制度空间、经济空间、社会空间描绘出现实图景。各省以构建保障体系、产业体系、支持体系和创新体系的政策手段来贯彻落实农业强国战略,勾勒出鲜明的农业强国建设着力点。政策目标是政策体系的归宿点,央地政策的精准匹配体现出协同治理的思想。在建设农业强国的实践中,各省级政府要统筹发挥好不同体系的作用,打造具有弹性的特色农业强国建设体系,协调好中央与地方治理的关系,实现央地协同发展。

考虑智能网联车辆影响的八车道高速公路施工区可变限速控制方法

为提升车联网环境下高速公路施工区交通运行效率及安全水平,提出了一种基于强化学习的可变限速控制方法.选取智能驾驶模型和真车试验模型,分别对传统人工车辆和智能网联车辆的跟驰行为进行建模,构建了以瓶颈下游路段交通流量为效率指标、瓶颈路段速度标准差为安全指标的复合奖励值,利用深度确定性策略梯度算法,分车道动态求解最佳限速值.仿真结果表明,所提可变限速控制方法在不同智能网联车辆渗漏率条件下均能有效提升交通流运行效率和安全水平,且在智能网联车辆渗漏率较低时,提升效果更加显著.当智能网联车辆渗漏率为1.0时,瓶颈下游路段交通流量提升10.1%,瓶颈路段速度标准差均值下降68.9%;当智能网联车辆渗漏率为0时,瓶颈下游路段交通流量提升20.7%,瓶颈路段速度标准差均值下降78.1%.智能网联车辆的引入能够提升至多52.0%的瓶颈下游路段交通流量.

我国瓦斯隧道施工技术进展及主要问题探讨

基于网络数据资料、期刊论著文献与现场施工资料,全面总结我国瓦斯隧道施工技术的进展与不足。结果表明:1)我国瓦斯隧道具有瓦斯工区里程长、瓦斯等级高、多分布于中西部地区等特征;2)瓦斯隧道施工灾害主要为瓦斯燃烧、瓦斯爆炸、瓦斯突出、瓦斯中毒窒息等事故,年事故发生数量总体呈下降趋势;3)我国瓦斯隧道设计施工规范近20年来得到了较为全面的完善,已颁布了铁路与公路行业标准、贵川渝等地方标准;4)隧道瓦斯工区安全施工主要依赖于超前探测、瓦斯监测、安全通风与揭煤防突等关键技术,在工程实践中各技术的关键施工参数得到了优化完善;5)绝对瓦斯涌出量测定方法与瓦斯工区等级动态调整机制是目前瓦斯隧道施工存在的主要问题,对瓦斯隧道的施工安全与成本控制影响巨大。建议根据隧道施工特征进一步开展隧道瓦斯防治专题研究,完善瓦斯隧道设计施工规范,为我国瓦斯隧道的安全高效施工提供理论与技术支撑。

乡村振兴背景下社会工作参与农村社区治理的路径探究

乡村振兴的实现是中国现代化进程中的关键环节。农村社区的治理不只是社会治理结构中最基础的部分,同时也是构成国家治理体系和治理能力现代化的关键支柱。党的十八大以来,党中央对我国农村社区治理问题高度重视,提出许多新观点和新思路。社会工作在推动农村社区治理、促进乡村振兴的过程中起着不可替代的作用。该文探讨在乡村振兴的背景下,社会工作参与农村社区治理的可行性、困境、提升策略等问题,期望进一步增强农村社区的治理能力,确保农村社区治理的高效性,并最终达到农村社区的良好治理目标。

民族地区地方性医学院校研究生导师指导研究生开展科研工作调查分析——以右江民族医学院为例

目的:分析民族地区地方性医学院研究生导师指导研究生的科研工作情况,为研究生导师队伍管理提供参考依据。方法:参考相关文献和学校研究生培养相关管理规章制度制定调查问卷,对76名硕士研究生导师进行问卷调查。结果:在指导研究生开展科研工作中,98.68%的导师选择与研究生面谈的交流方式;89.47%的导师选择让学生参与自己的课题研究;81.58%的导师每年投入的累计时间大于3个月;77.63%的导师每学期与研究生见面次数在6次及以上;89.48%的导师跟研究生见面时交流时间大于0.5小时;38.16%的导师对研究生投入的科研经费2.0万元以上。97.37%的导师认为研究生参与科研工作积极性高;90.79%的导师认为研究生有学术责任感;76.32%的导师认为研究生思考问题不全面,69.74%的导师认为研究生的基础知识不牢固。结论:该校应加强管理,确保导师在研究生科研素质培养中的时间、经费等的投入,同时导师应要求学生重视科研思维的培养和基础知识的学习。

革命老区政府聚焦高质量发展的话语透视:注意力分配及其变化——基于《政府工作报告》的文本分析

革命老区振兴发展是区域协调发展的重要战略任务。老区政府聚焦高质量发展领域的注意力体现了政府的重视程度,其变迁过程反映了政府关注的内在规律,对提升政府治理效能有重要意义。采用文本分析法,以赣闽粤、陕甘宁、左右江、大别山和川陕五大革命老区《政府工作报告》(2013—2023)为分析文本,探讨老区政府统筹高质量发展进程中的注意力配置。结果表明,革命老区始终以经济建设为中心,以政治建设为统领,文化、社会、生态文明建设齐头并进,“五位一体”协调发展并呈现明显的区域特色。在注意力变迁方面,各维度注意力变迁总体平稳、局部曲折,呈现升降分明、稳定变化趋势,而聚焦生态文明维度的注意力分配比重增多,阶段波动。建议老区政府建立注意力分配机制,规避政策出台的时滞性;区别“柔性”与“刚性”注意力,强化政策协同;持续加强生态文明建设领域的注意力分配,增进布局协调性。

考虑路面结构影响的低路堤动应力响应分析

以尼日利亚某公路为依托,对考虑路面结构层的砂砾填料低路堤在交通荷载作用下的动应力分布规律进行了研究。首先通过现场测试方法分析了行驶速度和轴重对路基动应力的影响,在此基础上建立三维有限元模型分析了不同路堤高度、不同超载率和不同路基填料模量对动应力分布的影响。现场测试结果表明:车辆的行驶速度越快,应力峰值越小,车重越重,路基内动应力越高,在路面较为平整的情况下,车重是影响路基动应力的主要因素,车速的影响较小。数值模拟结果表明:路基内动应力与路堤高度、超载率和路基填料的模量均成正比,路堤高度由1 m增加到2 m时,路基工作区由1.92 m下降到1.79 m,超载率由0增长到125%,路基工作区深度由1.77 m增加到2.73 m,增了54.2%,路基模量从80 MPa提高到160 MPa时,路基工作区深度从1.77 m下降到1.58 m,下降幅度为10.7%,试验结果表明超载对路基动应力的影响最大。结论为低路堤公路设计提供了参考。

习近平特色农业发展理念的科学内涵与时代价值

习近平特色农业发展理念萌芽于其七年知青时的乡村农业生产实践,形成于地方从政时的区域农业发展探索,升华于治国理政时的大国农业体系构建。随着社会主要矛盾转变,习近平认为新时代特色农业发展应着力解决发展不平衡不充分问题,构建现代产业体系、绿色生产体系和新型经营体系,营造良好的农业发展环境。习近平特色农业发展理念继承和丰富了马克思主义农业理论,是引领“大国小农”高质高效发展特色农业的行动指南,是推进实现全体人民共同富裕的根本遵循,为世界提供了推进实现农村农民共同富裕的中国方案。

残膜回收机有效作业面积监测系统设计研究

为便于新疆棉田残膜回收的精准作业收费和补贴,设计了一种残膜回收机有效作业面积监测系统。通过仿真试验对比锁相放大器降噪前后残膜回收机作业时经纬度数据,得出锁相滤波对于噪声环境有较好的抗干扰性能;采用高斯投影正算方法将降噪后经纬度数据转化为平面坐标,得出1.5°带的高斯投影的相对误差相较于3°带降低了0.01%。同时,利用卡尔曼滤波算法和构成角方法筛选有效作业轨迹,使用缓冲区法计算重复作业面积,最终利用轨迹算法精准获取残膜回收机有效作业面积,得出所设计的残膜回收机有效作业面积监测系统对于大块农田测量时相对误差为2.6%,对于小块农田测量时相对误差为3.3%。研究结果表明:所设计的残膜回收机有效作业面积监测系统可以精确计算出残膜回收机的有效作业面积,为残膜回收机作业质量评估提供了一定的理论基础。

预防为先:沂蒙革命根据地的医疗卫生宣传工作探究

沂蒙革命根据地的医疗卫生宣传是战时疾疫防治工作的重要组成部分,是医疗卫生工作的前置和有益补充,对疾病预防、控制以及日常生活环境改善具有积极的推进作用,这一作用在当时战斗频繁、缺医少药、医疗卫生环境极端困难的情况下尤为重要。在艰苦的战时环境中,沂蒙革命根据地在党的领导下,坚持预防为先的原则,积极开展医疗卫生宣传工作,维护了根据地人民的生命和健康安全,进而为根据地的巩固与发展提供了重要保障。