拉力作业上肢肌肉疲劳评价模型研究

为避免作业人员肌肉疲劳累积,预防工作相关肌肉骨骼系统疾患(WMSDs),提出一种基于肌力降幅(FD)-主观疲劳评分(RPE)的肌肉疲劳评价模型。首先设计并开展模拟拉车作业试验,招募10名大学男生参与测试,测量不同时刻右手最大剩余肌力,并记录基于Borg CR-10量表的RPE值;然后归一化处理各时刻FD,建立不同姿势、不同负荷下的3个拉力作业上肢肌肉疲劳评价模型,并结合试验条件分析不同模型之间的差异。研究表明:RPE与FD间有线性关系,RPE-FD关系可能具有姿势属性;所建模型合理,可用于评价拉力作业人员工作过程肌肉疲劳,并可为施力作业过程肌肉疲劳监测与作业任务分析提供依据和手段。     

作业人员肌肉施力疲劳评价模型

为评价施力作业过程中人员肌肉疲劳状态,建立基于肌力(F)的主观肌肉疲劳评价模型。通过模拟拉车作业试验获得不同时刻拉力值以及手臂和腰部主观肌肉疲劳评分(RPE),归一化处理肌力降幅(FD)值,以消除个体差异;通过相关性分析方法研究肌力降幅归一化值(NFD)与RPE之间的关系;通过回归性分析方法,分别构建以NFD为自变量的手臂与腰部RPE回归方程(即RPE-NFD回归方程),并研究手臂与腰部PRE随时间变化特征。结果表明:RPE与NFD显著线性正相关; RPE-NFD回归方程能够描述施力作业过程中RPE随FD变化的情况;所建评价模型能反映肌肉疲劳随时间发展的特征,并可用以获得作业人员不同施力作业以及不同作业时间下的RPE值。     

高温高湿环境下人员劳动负荷与疲劳水平试验研究

为了找出高温高湿作业环境下人员劳动强度对生理、心理指标的影响规律,在实验室建立了高温高湿环境模拟体系.试验人员选择年龄相近、身体状况相仿的50名在校大学生,设定了微风(风速小于1.5 m/s)及湿球黑球温度(WBGT)为26℃、33℃、35℃、38℃以上4种环境条件,试验人员按事先规定的运动方式从事极重体力劳动和重体力劳动负荷训练,实时监测人员心率和评价主观疲劳程度,计算人员心血管负荷(CVL)和主观疲劳程度,对数据进行相关性分析,并绘制不同劳动负荷、不同环境温度下的柱状趋势图.结果表明,在同等劳动负荷下,人员心血管负荷和主观疲劳程度与环境温度(WBGT)存在正相关性.根据人员心血管负荷预警级别,提出当作业环境温度(WBGT)达到35℃及以上时,应立即停止人员重体力和极重体力劳动负荷作业.根据试验结果,结合现场实际,提出从事高温高湿作业的人员,应合理安排劳动和作息,加强水盐及营养的补充,加强个体健康监护.     

煤矿井下工人体力劳动负荷及疲劳调查研究

本文以心率测定分析为主要指标测定井下工人作业时的心血管等机体反应用来评价中国煤矿工人的体力劳动负荷，疲劳程度等。通过这一调查实验探讨适合煤矿井下工人的工作方式和负荷标准，并提出有关的改进建议。这对改进工作条件、减少工人疲劳程度、提高工作效率、减少工伤事故等方面具有切实可行的意义。     

煤矿井下工人体力劳动负荷及疲劳调查研究

本文以心率测定分析为主要指标测定井下工人作业时的心血管等机体反应用来评价中国煤矿工人的体力劳动负荷，疲劳程度等。通过这一调查实验探讨适合煤矿井下工人的工作方式和负荷标准，并提出有关的改进建议。这对改进工作条件、减少工人疲劳程度、提高工作效率、减少工伤事故等方面具有实切可行的意义。     

静态单手拉车作业最大耐受时间建模

为分析单手拉车作业肌肉疲劳情况,设计并完成模拟静态手拉叉车试验:通过测量拉车前后单臂拉力的变化及最大耐受时间(MET),记录基于Borg CR-10主观疲劳评分表(RPE)的身体疲劳度,探讨负荷和身体质量指数(BMI)对MET、剩余拉力、力量衰减程度和RPE的影响;并基于试验数据构建单手拉车作业肌肉疲劳MET预测方程。试验结果表明,仅负荷显著影响MET;所构建的以指数函数和幂函数为基础的MET方程与现有方程具有一致性;用所建方程得到的预测值与实测值偏差优于用现有MET方程得到的结果。     

间歇静态拉力作业人员肌肉疲劳发展研究

为了解间歇静态拉力作业中人员肌肉疲劳发展特征及其与连续静态拉力作业肌肉疲劳发展的差异,减少肌肉疲劳累积,降低罹患工作相关肌肉骨骼疾患(WMSDs)风险,设计并开展间歇静态拉力作业试验,招募8名大学男生参与试验,测量不同工休比下不同时刻的肌力(F),并记录主观疲劳评分(RPE),然后运用统计学方法分析F和RPE。研究表明:间歇静态拉力作业不同工休比下F曲线走向基本一致,作业结束时刻F值和RPE值均未见统计学显著性差异;组内不同时刻相同部位以及相同部位不同时刻的一些RPE存在显著差异;间歇静态和连续静态拉力作业肌肉疲劳发展存在显著差异,间歇作业中肌肉疲劳累积显著低于连续作业,可考虑采用本文所研究工休比进行拉力作业工作安排,需人力完成的静态作业宜采用间歇静态施力以减缓肌肉疲劳累积。     

煤矿井下气候参数和劳动强度对矿工生理参数影响的研究

对机械化采煤工作面的采煤机司机和支柱工的劳动心率和能量代谢进行了现场实测。就气候参数和劳动强度对作业人员的生理参数影响进行了模拟实验,取得一些实验研究成果。对改善劳动条件和作业环境,提高生产效率,保护井下矿工的身心健康与安全,提供了科学依据。     

中国煤矿工人体能负荷、疲劳与工伤事故

煤矿井下事故对矿工威胁很大，体力负荷过重而导致疲劳是引起事故不可忽视的原因。测定不同工种井下矿工的体能负荷情况，并根据ＦＩＸ疲劳指数的测定，分析矿工劳动负荷与工伤事故发生之间的关系。研究表明，在疲劳状态下事故发生的危险性增加；劳动负荷越重，疲劳越重相对的事故发生率也越高。减轻疲劳对预防事故发生与保证工作安全具有很重要的意义     

矿工运动负荷实验对心率影响研究

最大心率预计值是评价工人负荷、疲劳与工作能力的重要指标。在一定的运动强度下与耗氧量、工作负荷程度呈线性关系。我们对１０１名井下矿工采用自行车功率计测定的方法，用ＢＨＬ６０００电脑心率测定仪测定其心率的变化以了解正常矿工心率变化的特点和规律，并提出建立中国煤矿工人的负荷与心率互换数学模型，进而作为评价体能负荷状态与疲劳水平的观察和评价指标之一。本试验结果推算矿工最大心率公式为１９４—年龄，建议今后在工作中以采用此数据为宜。     

基于相对心率的体力劳动强度评价方法

体力劳动强度等级的合理划分是劳动者获得合理报酬和身心健康的重要保证。在研究现有体力劳动强度评价方法的基础上,通过实验进行数据的采集并对其进行标准化处理,然后运用回归分析方法建立起以相对心率为解释变量、RPE值为因变量的体力劳动强度评价模型,进行了年龄和环境因素的修正,最后在某企业进行了应用。该模型相对传统体力劳动强度评价方法的改进主要体现在三个方面:第一,指标值测量简单,提高了可操作性;第二,评价等级划分更精确;第三,考虑了年龄和环境因素。该方法在广大工矿企业具有较好的应用价值。     

Flicker Test as a Load Measurement During the Combined Effect of Heat and Noise

This study was a joint physiological and psychological experiment undertaken to determine changes in physiological and psychological human functions under the combined influence of heat, noise, and physical activity. Seven experimental situations were simulated in a climatic chamber with different configurations of three independent variables: heat (40 °C), noise (98 dB), and physical effort (30% of maximum volume of oxygen uptake—V0₂ max). Five psychological variables (critical flicker fusion—CFF, hand tremor, reaction time, subjective climate evaluation, and subjective evaluation of the given condition load) and two physiological variables (heart rate and rectal temperature) were monitored. Results indicate that CFF changed (increased) significantly when more than one experimental variable was applied. These changes coincided with significant changes in both subjective climate evaluation and subjective evaluation of a given condition load. There were no significant changes in psychomotor functions (hand tremor and reaction time). None of the observed physiological parameters were above the critical value. The results suggest that CFF can be treated as a psychophysical load indicator.     

Cardiovascular Strain of Sawmill Workers in South-Western Nigeria

This study aimed to assess cardiovascular strain during sawmilling operations in terms of physical workload, based on heart rate changes. We measured resting and working heart rates and calculated cardiovascular load (%CVL), cardiovascular strain (%CVS) and relative heart rate (%RHR) in 35 sawmill workers. Based on heart rate only, the work in sawmills was classified as very heavy and extremely heavy. Similarly, a high-level category was recorded for %CVL and a very high range for %CVS. Thus, the workload in sawmill operations is usually very high and can lead to physiological strain of the workers. There is a need to redesign the work content of this occupation to prevent excessive strain in the workers, as this will increase their productivity and reduce their health risk.     

不同劳动强度下人体呼吸参数变化实验研究

人体呼吸参数对呼吸防护装备内部微环境的稳定性至关重要，为获得不同劳动强度下人体呼吸参数及变化规律，以相对心率指数表征劳动强度等级并设计构建呼吸参数采集系统。通过开展多人次不同劳动强度呼吸实验，记录实时瞬时心率、呼吸压力、呼吸频率数据并采集呼出气样本，进行气相色谱分析。研究结果表明:相对心率指数能够消除劳动强度表征中的个体差异及劳动形式差异，对劳动强度具有良好表征作用；呼吸压力及频率随劳动强度增加呈现增强和变大的趋势；心率及呼吸压力信号的样本熵显示，心率稳定性随劳动强度的增加而降低，呼吸模式稳定性则增强；呼出气中O2含量随劳动强度增加而降低，CO2与H2O含量呈现增长趋势，绝对变化量及变化比例随劳动强度不同呈现明显差异。     

高温环境下不同体力劳动强度对心血管负荷指数影响研究

基于心率变化的心血管负荷指数作为评估人体疲劳程度的指标之一,得到国内外专家学者的广泛研究。为进一步研究高温环境下不同体力劳动强度对心血管负荷指数的影响,探讨高温作业下不同劳动强度人体疲劳程度的变化,分析出不同温度下人体可接受的体力劳动强度。通过采用实验仓模拟不同的高温环境,以心血管负荷指数(%CVL)作为人体疲劳程度的分级指标,最终得到了高温环境下从事不同体力劳动强度的心血管负荷指数回归方程,以及不同高温环境下人体可承受能力下可进行的体力劳动强度,为高温环境劳动者制定合理和健康的作业安排提供科学依据。     

KTV娱乐场所火灾荷载调查与统计分析研究

火灾荷载的选取是设计火灾的重要环节,同时也是保证火灾风险评估科学可靠的关键因素。火灾荷载的实地调查和统计分析是火灾荷载研究工作的重要手段。通过对全国各地23家KTV娱乐场所的349个包间进行调查,统计出KTV包间可燃物种类、质量情况以及不同可燃物所占质量比。并且,通过调查得出KTV包间的面积情况。对所调查的349个包间的火灾荷载分布情况进行研究,利用数理统计的方法得到了该类场所火灾荷载密度、均值、最大值、最小值等数据,为火灾风险评估中火灾场景的设计提供了数据基础。     

Physiological Method of Evaluating Protective Clothing for Work in a Cold Environment

The purpose of this study was to determine the usefulness of physiological studies in the evaluation of protective clothing for work in a cold environment. The study included the examination of the dynamics of changes in chosen physiological parameters (core and skin temperatures, heart rate, pulmonary minute ventilation) as well as physical ones (the temperature and relative humidity under the clothes) during work in protective clothing with unknown thermal insulation. The experiment was conducted in extreme environmental conditions (–10 and –15°C) at a work load defined by the clothing manufacturer as moderate. Results show that thermal equilibrium was achieved and maintained throughout the investigated work time (60 min) and that the protective clothing ensures safety on the time scale of a regular 8-hour work day. It was also shown that the dynamics of thermal stress physiological parameters can be used to determine the maximum duration of exposure for cold protective clothing with unknown thermal insulation.     

Physical Strain and Work Ergonomics in Farmers with Disabilities

In agriculture, occupational injuries are common, and several of them lead to permanent physical disability. The objective of this case study was to assess the strain and the ergonomic needs of four farmers (aged 34–49 years) with physical disabilities. A maximal bicycle ergometer test or an arm-crank test was done to assess their maximal heart rate (HR _max) and maximal oxygen consumption (V0_2max). The strain at work was analyzed by measuring heart rate (HR), muscle activity (EMG), and the rating of perceived exertion (RPE). The farmers were interviewed as to possible and impossible work tasks and the ergonomic redesign measures taken to improve the work environment. The work tasks performed were mainly light or moderate work for the cardiorespiratory system according to mean HR (88-102 beats/min), the percentage of HR range (17–31% HRR), and the relative V0₂ (22–46% V0_2max). The mean activity of the trapezius muscles was 0.4-9% of the maximal voluntary contraction (%MVC). All the participants had work tasks they were unable to perform. They had made ergonomie redesign changes mainly to the tractor. This case study showed that some agricultural work tasks were possible for farmers with physical disabilities and that the physical strain associated with these tasks was mainly light or moderate.     

高温户外环境电网作业人员热应激预测评价*

为了预测分析户外高温环境下电网作业人员热安全风险,采用预测热应激（Predicted Heat Strain,PHS）模型,考虑人体基础代谢率个体差异性和人体移动与风速对服装热阻和湿阻的影响,应用改进后的预测热应激模型对多种户外高温作业环境工况和不同劳动强度下电网作业人员的核心体温、出汗量等生理参数和最大允许暴露时长进行计算分析。结果表明:在户外高温环境中,随着环境温度、相对湿度和新陈代谢率的升高,电网作业人员的核心体温也随之升高,湿热环境中风速的增加会加剧电网作业人员的热应激;当电网作业人员从事代谢率为240 W/m2高劳动强度工作时,可接受的最大工作时长相比代谢率为190 W/m2中度劳动强度工作时长减小50%以上。研究结果可为电网公司夏季户外工作组织策略制定和作业人员热安全防护提供参考支持。     

Factors affecting children's participation and amount of labor on family farms

METHOD: A two-stage decision-making model is estimated to explain children's participation and labor supply on family farms using unitary and cooperative bargaining frameworks. RESULTS: Results indicate that parents have different preferences about whether their children work and how much they work. The models incorporate non-economic factors and allow for different stochastic processes in the participation and labor supply decisions. CONCLUSIONS: Concerns about children's social development appear to be crucial in deciding children's labor participation, while the child's economic contribution significantly influences both whether they work and how much they work. Some variables affect the two decisions differently. For instance, the higher the parents' education level, the higher the probability children will work but the fewer hours they will work.