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.

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.

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.

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.

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.

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。

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。

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。

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。

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。

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。

地铁站办公区细颗粒物之金属特性分析及工作人员健康暴露水平分析

为了研究地铁站办公区PM_(2.5)的特征和工作人员的暴露水平,选择3种不同类型的地铁站进行采样和分析。采用电感耦合等离子体质谱法(Inductively Coupled Plasma Mass Spectrometry,ICP MS)分析PM_(2.5)样本中的22种元素,利用微环境模型对地铁站工作人员的PM_(2.5)及元素质量浓度暴露水平进行评估,并与普通室内工作人员进行对比。结果显示,办公区PM_(2.5)质量浓度普遍高于室外,超过了世界卫生组织给出的指导值。办公区PM_(2.5)金属元素富集明显,地铁工作人员每天暴露于Fe、Mn、Cu、Ni、Cr、Co等金属元素的日暴露剂量明显高于普通室内工作人员,地铁站办公区的空气质量应引起关注。

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。

新时代革命老区本科院校人才工作高质量发展研究——以龙岩学院为例

龙岩学院作为闽西革命老区唯一一所地方本科院校,是龙岩市人才高地,为龙岩市产业兴旺、科技进步、文化传承、实现人才强市战略目标提供重要人才支持。当前龙岩学院人才发展存在缺乏统筹规划、人才吸引力弱与聚合力不足、人才转化能力弱与人才断层、当地大学毕业生供需失衡与服务地方意愿弱等问题,亟需基于“知、举、用、待、育”的人才工作理念,锚定育才“靶向标”,握准选才“定盘星”,建好引才“资源库”,打造留才“蓄水池”,打出政策“组合拳”,涵养人才“好生态”,树牢人才“风向标”,释放人才“新动能”,以期更好实现地方本科院校人才工作高质量发展,为闽西革命老区高质量发展示范区建设提供人才支撑。

中华民族共同体意识融入校园教育路径研究——以云南民族地区民间文学类国家级“非遗”为例

民间文学类非物质文化遗产与中华民族共同体意识教育分属文化和教育两大不同系统,但却有着内在的关联。其关联在于不同民族的民间文学类“非遗”项目中蕴含着丰富的中华民族共同体意识,为开展中华民族共同体意识教育提供了直接的资源。在云南各民族民间文学“非遗”项目的教育资源、媒介优势及其多渠道多层次进校园的教育路径,对云南边疆民族地区中华民族共同体意识教育极具意义。

典型沥青路面结构路基工作区深度分析

该文基于实测“胎-路”界面条件,分别采用弹性半空间体理论、层状弹性体系理论计算不同工况下典型沥青路面结构的路基工作区深度,计算结果表明路基工作区深度随轴重显著变化,并基于计算结果提出路基工作区深度的推荐值:轴重小于100 kN时,路基工作区深度取0.8 m;轴重小于130 kN时,路基工作区深度取1 m;对于轴重小于150 kN的道路,路基工作区深度建议值为1.2 m。对于路基工作区范围内的土基,必须采取有效的工程处理措施以确保路基路面结构具备足够的承载力。

浅析食品车间加工作业区划分

食品车间科学合理的作业区划分,是实现良好食品生产环境的先决条件。现有的国家标准GB 14881—2013仅对食品车间作业区划分做了原则性规定,目前除饮料等6种产品颁布了新的审查细则外,其他产品系采用2006年版审查细则,均未对作业区划分作具体规定。本文介绍了我国食品车间环境卫生等级划分及车间空气洁净度等级划分体系,收集整理了国家最新行业卫生规范或审查细则对不同作业区空气洁净度的要求,统计归纳了饮料等国家最新发布的审查细则中对相关产品作业区划分的具体规定,提出了食品加工作业区划分的一般原则,以供参考。