山丘地形下近浅埋煤层综采面静动载叠加的矿压显现特征研究

针对近浅埋综采面过山丘地形发生强矿压显现的问题,采用现场监测、理论分析与数值模拟相结合的方法,建立山丘静载应力传递模型和不同岩层赋存特征的沙土型与土石型山丘工作面关键块体结构力学模型,分析山丘地形工作面矿压发生机理。研究表明:山丘静载向工作面传递的垂直应力呈钟形分布,山丘高静载应力易激发弱铰接结构失稳;山丘坡体中关键层的有无导致了土石型和沙土型山丘工作面矿压发生机理的差异性;坡体断裂块的倾斜回转运动是沙土型山丘工作面发生强矿压的主导因素,断裂块不同的倾斜回转方向导致工作面在上坡段矿压显现缓和而下坡段显现剧烈;土石型山丘工作面的矿压显现主要受坡体中关键块体结构稳定状态的控制,工作面在上坡初和坡顶段动载矿压强烈而下坡段后期较缓和。数值计算结果与现场监测和理论分析相符。     

Effects of Neutral Posture on Muscle Tension During Computer Use

This study focused on developing a new approach to seated work positions as conducted on 67 office workers who use a Visual Display Terminal (VDT) as a major function of their working day. Muscle tension was measured by surface electromyography (sEMG) while participants were asked to adopt 4 selected working postures. Pain was measured before and after ergonomic intervention on the Nordic scale, which was modified for this study. Adjustable workstations were used to place participants in desired positions during the clinical testing sessions and the extended intervention period. Results indicate the effects of this ergonomic intervention may have positive effects on muscle tension and pain, significant enough to encourage employers to implement training and workstation modifications following these guidelines.     

Analysis of Conditions and Organization of Work of Notebook Computer Users

Abstract

Aim. The aim of this study was to evaluate working conditions with a notebook computer (notebook) as a potential cause of musculoskeletal disorders. Material and methods. The study had 2 stages. The first one was a questionnaire survey among 300 notebook users. The next stage was an expert analysis of 53 randomly selected workstations. The questionnaire survey included questions about the participants, their working conditions, work organization and also duration of work with a notebook. Results and conclusions. The results of the research showed that most examined operators used a notebook as a basic working tool. The most important irregularities included an unadjustable working surface, unadjustable height of the seat pan and backrest, unadjustable height and distance between the armrests and no additional ergonomic devices (external keyboard, docking station, notebook stand or footstool).     

Ergonomic analysis of working postures using OWAS in semi-trailer assembly,applying an individual sampling strategy

In semi-trailer assembly, workers are exposed to several physical risk factors. Awkward working postures have not yet been investigated in semi-trailer assembly, although they are known to be a major risk factor for musculoskeletal disorders. We therefore conducted a comprehensive ergonomic analysis of working postures using the Ovako working posture analysing system (OWAS), with an individual sampling strategy. The postural load in semi-trailer assembly was assessed on the basis of 20,601 observations of 63 workers executing a representative set of nine work tasks. According to the OWAS, the postural load of various working postures and body part positions may have a harmful effect on the musculoskeletal system. We therefore give examples of corrective measures that could improve awkward working postures. Applying an individual sampling strategy was revealed to have advantages over a collective strategy, so this is recommended for future ergonomic analyses.     

提高基层班组JSA质量的管理实践

工作安全分析(简称JSA)作为有效的危害识别和风险控制工具被广泛使用,但基层班组员工所做JSA的质量一直不高,具体表现为员工虽然清楚JSA的各个环节,却不能高质量的完成.尽管这在一定程度上与基层员工文化素质低,文字表达能力差有关,但也是管理者缺乏具体和优秀的指导所致.针对实施JSA的各个环节,分析制约质量提升的具体原因,以标准规范为基础提出具体可行的改进措施,实施效果良好.     

煤巷掘进过程中粉尘浓度影响因素分析

为了掌握煤巷掘进过程中粉尘浓度变化的影响因素,根据气固两相流理论,针对矿井掘进工作面的特点,采用计算流体力学的离散相模型（DPM）考察了掘进巷道风速、风筒直径、风筒出风口到掘进工作面距离以及风筒的悬挂高度对粉尘浓度变化的影响。结果发现：当掘进巷道风速为0.25-4 m/s时,提高巷道内的通风风速,可以降低巷道内的粉尘浓度,缩短呼吸性粉尘浓度达到稳定的时间,减小工作面粉尘的危害;有利于通风除尘的风筒相关参数为风筒直径0.4-0.6 m、风筒出风口到掘进工作面距离6-7 m、风筒悬挂高度2.0-2.2 m。     

秦皇岛市城镇水土保持工作主要做法及成效分析

随着城镇建设的迅猛发展,项目开发建设占用大量具有生态功能的地表,人为造成的水土流失日趋严重,因此做好城镇水土保持工作至关重要。秦皇岛市从2004年起通过制定规划、建立工作体系、强化预防监督、加强宣传等措施,水土保持工作取得了显著成效:提高了全民水保法制观念,规范了城镇建设项目管理工作,城郊水土流失治理度达90%以上,城区碧水工程已基本完成,实施了城市雨水资源利用试点工程,城市区人均绿地面积达到12 m2,森林覆盖率达40%以上。     

掘进面出风口风流与风幕调控下的粉尘分布响应曲面优化研究*

为了解决煤矿掘进面风筒出风口参数不能动态变化,而传统风幕全断面控尘效果不理想引起的粉尘浓度高等问题,通过分析风幕和出风口参数对粉尘分布规律的影响,以此得到合理的出风口风流与风幕综合调控方案,降低粉尘浓度。以陕西神木柠条塔煤矿N1212巷道为研究对象,利用Fluent软件建立出风口风流与风幕综合调控的粉尘场有限元模型,设计出风口风流及风幕综合调控响应曲面实验,得到最佳综合调控方案为:风幕射流出口宽度为0.16 m,风幕射流出口速度为6 m/s,出风口口径为0.9 m,出风口右偏角度为3°。搭建相似模拟实验平台来验证最佳综合调控方案,研究结果表明:调控后回风侧行人呼吸处和司机位置处粉尘平均浓度分别降低89%和81%,有效改善掘进面作业环境。     

建筑结构活荷载标准与灾害荷载设防水平 --使用年限的影响

旨在提供不同使用年限建筑结构对应的活荷载水平.分析了结构可靠度理论的特点,揭示了设计使用年限是结构可靠度的时间特征.应根据不同设计使用年限活荷载的超越概率等于常规设计荷载超越概率的原则确定活荷的载标准;通过建立不同设计使用期、不同设计基准期与活荷载取值的关系,给出了不同使用年限对应活荷载与灾害荷载设防水平.     

战略环境评价系统及工作程序

介绍了战略环境评价系统组成的五个要素 ,即评价者、评价对象、评价目的、评价标准和评价方法 ,分析了其相互关系及各要素与战略环境评价系统的关系 ,并提出了战略环境评价工作程序。