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.     

A ventilation cooling shirt worn during office work in a hot climate: cool or not?

The aim of the study was to identify whether a ventilation cooling shirt was effective in reducing heat strain in a hot climate. Eight female volunteers were exposed to heat (38?°C, 45% relative humidity) for 2?h with simulated office work. In the first hour they were in normal summer clothes (total thermal insulation 0.8?clo); in the second hour a ventilation cooling shirt was worn on top. After the shirt was introduced for 1?h, the skin temperatures at the scapula and the chest were significantly reduced (p?<?0.05). The mean skin and core temperatures were not reduced. The subjects felt cooler and more comfortable by wearing the shirt, but the cooling effect was most conspicuous only during the initial 10?min. The cooling efficiency of the ventilation shirt was not very effective under the low physical activity in this hot climate.     

Stressful work characteristics,health indicators and work behavior: the case of machine operators

This article shows the results of research on psychosocial risks for a group of machine and plant operators (n?=?1014) from the construction, chemical, energy, mining, metal and food industries in Poland. The Psychosocial Risk Scale designed in Nofer Institute of Occupational Medicine (NIOM) by Moscicka-Teske and Potocka was used to indicate the occurrence of general and specific occupational stressors and the level of their stressfulness. The results revealed that the studied machine and plant operators experience job context stress – related to working environment features concerning work organization – more frequently than job content stressors – related to the type of tasks they perform. Moreover, a correlation analysis between work features and the health and occupational functioning of the respondents revealed significant but weak relationships between the variables (from ?0.08 to ?0.23). Comparative analysis revealed the differences between the studied sectors. Such a comparison makes it possible to set goals for each sector and to attempt to improve the distinctive areas.     

The Relationship Between Shift Work Schedules and Spillover in a Sample of Nurses

The aim of the present study was to estimate spillover effects between the work and the family sphere in a sample of nurses (N = 2058). Hierarchical regression analyses investigated whether shift work schedules were associated with negative or positive spillover, both from family to work and vice versa, controlling for demographic factors, job demands and decision latitude. With daytime work as a reference group, all types of shift work (day and evening shift, night shift only and rotating 3 shift) were associated with higher negative work-to-family spillover. Night work was associated with significantly less negative family-to-work spillover. None of the different shift work schedules were related to any type of positive spillover. The results indicate that working outside of daytime hours is less compatible with workers’ family lives, compared to working ordinary day shifts. On the other hand, working night shifts only was associated with reduced negative family-to-work spillover.     

考虑岩石应变软化的厚煤层综放开采覆岩破坏特征研究

为了分析裴沟矿31采区的煤炭开采对上部魔洞王水库的影响,以及评价水体下开采的安全性,首先分析了岩土体材料在三轴压缩试验中表现出来的应变软化现象,认为岩石峰后的软化能够说明覆岩破坏后的力学特性;然后介绍了FLAC3D中应变软化模型;最后分别建立Mohr—Coulomb理想弹性模型和应变软化模型的数值模型,针对工作面推进过程中覆岩移动破坏的特征以及顶板导水裂隙带发育规律,分析了两者计算结果的差别,计算结果表明:应变软化模型对覆岩移动破坏特征的计算更加准确,能够说明工作面推进过程中覆岩移动规律,通过其计算得到的导水裂隙带高度的预计对水体下采煤的安全性评价有一定的参考价值。     

The role of hindrance stressors in the job demand–control–support model of occupational stress: A proposed theory revision

Previous research on the job demand–control–support (JDCS) model of occupational stress has generally been inconsistent at best regarding a key issue: the interaction of demands, control, and support in predicting employee health and well‐being. However, the model continues to be tested in a variety of studies and academic journals owing to its intuitive appeal. By incorporating conservation of resources theory with knowledge from the challenge–hindrance stressor framework, we proposed that hindrance stressors, not the challenge stressors commonly assessed when testing JDCS theory, will provide validation for the model. A two‐wave panel study of 228 employees in a variety of occupations provided support for three‐way interactions between hindrance demands, control, and support predicting job‐related anxiety and physical symptoms. Three‐way interactions using a challenge demand (forms of workload) were not significant, consistent with our propositions. In summary, this study supports the buffering effect of control and support on the relationship between job demands and strain only when job demands reflect hindrance stressors, thereby proposing to alter the JDCS model by specifying that it applies primarily to hindrance stressors in a job hindrance–control–support model. Copyright © 2015 John Wiley & Sons, Ltd.     

Degradation and mineralization of 2-chioro-, 3-chloro- and 4-chlorobiphenyl by a newly characterized natural bacterial strain isolated from an electrical transformer fluid-contaminated soil

A bacterium classified as Achromobacter xylosoxidans strain IR08 by phenotypic typing coupled with 16S rRNA gene analysis wasisolated from a soil contaminated with electrical transformer fluid for over sixty years using Aroclor 1221 as an enrichment substrate.The substrate utilization profiles revealed that IR08 could grow on all three monochlorobiphenyls (CBs), 2,4'- and 4,4'-dichlorobiphenylas well as 2-chlorobenzoate (2-CBA), 3-CBA, 4-CBA, and 2,3-dichlorobenzoate. Unusually, growth was poorly sustained on biphenyland benzoate. In growth experiments, IR08 degraded all CBs (0.27 mmol/L) in less than 96 h with concomitant stoichiometric release ofinorganic chloride and growth yields were 2-3 times higher than those observed on biphenyl. In contrast to most of the chlorobiphenyl-degrading strains described in the literature, which are reported to form CBA, no metabolite was identified in the culture broth byHPLC analysis. When co-incubated with respective CBs and biphenyl, strain IR08 preferentially utilized the chlorinated analoguesin less than 96 h while it took another 264 h before 90% of the initially supplied biphenyl could be degraded. The promotion of co-metabolic transformation of halogenated substrates by the inclusion of their non-halogenated derivatives may not therefore, result inuniversal benefits.     

The shaped blasting experimental study on damage and crack evolution of high stress coal seam

In the deep high stress coal and rock mass, the efficiency of the ordinary blasting method is constantly affected by the high pressure. This study investigates the shaped blasting technology with increased blasting efficiency, develops a mechanical model for coal crack expansion during shaped blasting, and examines the force-energy action of energy-gathering jets during coal splitting. The established model was combined with experiments and simulations to reveal the damage and evolution of cracks in coal and rock masses. Experiments demonstrate that shaped blasting can create an energy-gathering jet that causes a directional fracture in the test block. The peak of compressive strain in the energy-gathering direction is 1.12 times greater than that of ordinary blasting, and the static action period of the explosive gas is prolonged by 1.3 μs according to the stress curve. Moreover, the peak pressure strain increased 3.2 times, and the pull strain peak increased 3.92 times. The damage amount was represented by the resistivity and ultrasonic wave speed, and shaped blasting causes 1.2 and 1.5 times greater damage than ordinary blasting. The research results provide technical methods for safe and rapid penetration blasting in deep high-ground stressed coal mines.