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781.
为了探求一氧化碳与水蒸汽参与瓦斯爆炸的化学反应动力学过程的阻尼效应,建立了受限空间中瓦斯爆炸反应的数学模型。数值计算结果表明,结果表明在瓦斯爆炸过程中,瓦斯-空气混合气体含有10%的一氧化碳,虽然会延迟瓦斯爆炸时间,抑制瓦斯爆炸,但是H、O自由基浓度、瓦斯爆炸温度和压力比不加入一氧化碳时升高,同时对CO2、NO的生成起促进作用;当混合气体中含有10%的水蒸汽时,H、O自由基浓度降低,瓦斯爆炸温度和压力也随之降低,致灾性气体CO2、NO的生成得到抑制。虽然一氧化碳对瓦斯爆炸有一定的阻尼效应,但是由于一氧化碳对部分致灾性气体的生成有促进作用,因此,在阻尼瓦斯爆炸方面,水蒸汽的效果要好于一氧化碳。 相似文献
782.
Anna-Christina Blomkvist 《International journal of occupational safety and ergonomics》2013,19(3-4):129-140
Nineteen persons “hypersensitive” to electricity and 20 nonafflicted persons were studied for 1 ½ years. The most discernible hypersensitivity symptoms were pricking sensations and redness in the face, but these symptoms were present in only half of the afflicted. Other symptoms were similar to symptoms experienced during office work and this study does not support the idea that electrosensitivity is one single syndrome. The “hypersensitive” persons improved significantly, mainly on neuropsychiatric symptoms, but the skin problems sustained— as did the belief about their cause. The afflicted persons used less conventional medication than the group of the nonafflicted, which suggests a general tendency for attribution to environmental factors. 相似文献
783.
Sławomir Zakrzewski Katarzyna Majchrzycka Agnieszka Brochocka Krzysztof Makowski 《International journal of occupational safety and ergonomics》2013,19(2):164-170
In most industrial enterprises, hazardous factors are present in quantities exceeding permissible levels. Such a situation requires using antidust respiratory protection. It has been suggested, however, that filters for respirators are not assessed properly and that lab results might not be related to real filtering efficiency in industry. This article contains test results of some commercially available filtering half-masks, including the effect of loading with real dust, high humidity, high temperature, and a combination of loading with dust and high humidity on the half-masks’ performance. The results show that the effect of these factors is considerable and that a combination of loading with silica dust and exposing to high humidity can cause a complete loss of performance. 相似文献
784.
本文通过对KZ1床层、KZ2床层、KZ1和KZ2复合床层在不同床层厚度条件下,对氯化氰蒸气的动活性进行对比试验,并对试验结果进行分析,得出了后者并非前两者之和,而有了大幅提高的结论。 相似文献
785.
Communities around the world have increasingly come to demand more involvement in decision making for local mining projects, a greater share of benefits from them if they are to proceed, and assurances that mineral development will be conducted safely and responsibly. At the same time, Bridge (2004) notes full legal compliance with state environmental regulations has become an increasingly insufficient means of satisfying society's expectations with regards to mining issues. There is now a recognised need for mineral developers to gain an additional ‘social licence to operate’ (SLO) in order to avoid potentially costly conflict and exposure to business risks. However, there is a correspondingly limited amount of scholarship specifically focused on SLO. More particularly, there is a need for research that uncovers those factors that lead to the issuance (or non-issuance) of a SLO in the complex and changeable environments that often characterise mineral development. In an effort to identify key determinants of SLO outcomes in the mining industry, this paper presents a comparative case study analysis of four international mining operations: Red Dog Mine in Alaska, USA; Minto Mine in Yukon, Canada; the proposed Tambogrande Mine in Peru; and the Ok Tedi Mine in Papua New Guinea. The analysis that is presented also makes use of insights from supplementary key informant interviews conducted by the author and the emerging literature on mining and communities. Five lessons for earning a SLO emerged from this analysis: (1) context is key; (2) a social licence to operate is built on relationships; (3) sustainability is a dominant concern for communities; (4) local benefits provision and public participation play a crucial role; and (5) adaptability is needed to confront complexity. 相似文献
786.
本文着重分析电磁兼容发射测量中的不确定度。以评定电源端子骚扰电压的不确定度为例,介绍发射测量不确定度的目的、不确定度源的种类、不确定度报告的评定方法及其Ucispr和不确定度在符合性判据中的运用。 相似文献
787.
Establishing “social licences to operate” with communities has become a significant corporate social responsibility agenda. The complex dynamics of these relationships can compound the impacts for communities when these contracts are not upheld. This article documents reflections from a rapid rural appraisal conducted in the Shire of Ravensthorpe in remote Western Australia after the Ravensthorpe Nickel Operation was “mothballed” 9 months into a projected 25-year lifespan. It captures how communication about the project and its time frames created a sense of consistency, predictability, certainty and trust – enabling social licence. The raising of hope and the emergence of mistrust underpin social, environmental and financial impacts of this event for the local community. Embedded in the theoretical dimensions of social licences, this case study highlights the problematic of social licences that engage with non-contractual stakeholders as partners in “booms” but have no legal responsibility towards them in times of “bust”. 相似文献
788.
ABSTRACTResidential care has increased in number of facilities and has grown in density in urban areas, yet it is disproportionately dispersed in cities and only beginning to meet the current long-term care need of older adults as an alternative to institutional and in-home care. California State Department of Social Services residential care facility data were linked with Los Angeles County census tract data to examine the spatial distribution of facilities through hot spot analysis of clusters of small and large facilities and zero-inflated negative binomial regression of census tract facility counts on older age and race groups, older disabled adults, and older adults in poverty in the area. The results show clusters of large facilities west of downtown Los Angeles and clusters of small facilities in the northern suburbs of the city in the San Fernando Valley. Increases in pre- and early-retired adults and older Hispanics in census tracts are associated with the greatest decreases in facility tract capacity in the area, whereas increases in the oldest old and older disabled adults are associated with the greatest increases. Understanding spatial disparities in residential care can help local agencies and developers plan and partner in more intentional and equitable development of facilities. The greatest opportunity for such development may lie in institutional tools for eldercare facility development such as the eldercare facility ordinance of Los Angeles and development of board and care facilities in residential zones of Los Angeles and other cities. 相似文献
789.
为开发高性能防护服以提升救援效率,基于人体试验,测量受试者穿戴灭火防护服、半封闭防化服、全封闭防化服以及基础服装(对照组)时静态条件下左右手握力值、疲劳度(RPE)和活动受限程度,通过方差分析、接受者操作特征(ROC)曲线图、相关性分析进行定量研究。研究结果表明:灭火防护服对消防员工效性能影响大于防化服,灭火防护服较对照组握力减小32%、RPE增大54%、活动受限程度增大35倍,且RPE和活动受限程度均与握力呈显著负相关(p<0.001)。研究结果可为消防员个体防护服装设计、测试、性能提升等提供理论支撑,也可为消防员生命安全保障研究提供基础数据。 相似文献
790.
Xueyou Li Wenqiang Hu William V. Bleisch Quan Li Hongjiao Wang Wen Lu Jun Sun Fuyou Zhang Bu Ti Xuelong Jiang 《Conservation biology》2022,36(3):e13839
In the Anthropocene, understanding the impacts of anthropogenic influence on biodiversity and behavior of vulnerable wildlife communities is increasingly relevant to effective conservation. However, comparative studies aimed at disentangling the concurrent effect of different types of human disturbance on multifaceted biodiversity and on activity patterns of mammals are surprisingly rare. We applied a multiregion community model to separately estimate the effects of cumulative human modification (e.g., settlement, agriculture, and transportation) and human presence (aggregated presence of dogs, people, and livestock) on species richness and functional composition of medium- and large-bodied mammals based on camera trap data collected across 45 subtropical montane forests. We divided the detected mammal species into three trophic guilds–carnivores, herbivores, and omnivores–and assessed the nocturnal shifts of each guild in response to anthropogenic activities. Overall, species richness tended to increase (β coefficient = 0.954) as human modification increased but richness decreased as human presence increased (β = –1.054). Human modification was associated with significantly lower functional diversity (mean nearest taxon distance [MNTD], β = –0.134; standardized effect sizes of MNTD, β = –0.397), community average body mass (β = –0.240), and proportion of carnivores (β = –0.580). Human presence was associated with a strongly reduced proportion of herbivores (β = –0.522), whereas proportion of omnivores significantly increased as human presence (β = 0.378) and habitat modification (β = 0.419) increased. In terms of activity patterns, omnivores (β = 12.103) and carnivores (β = 9.368) became more nocturnal in response to human modification. Our results suggest that human modification and human presence have differing effects on mammals and demonstrate that anthropogenic disturbances can lead to drastic loss of functional diversity and result in a shift to nocturnal behavior of mammals. Conservation planning should consider concurrent effects of different types of human disturbance on species richness, functional diversity, and behavior of wildlife communities. 相似文献