航电电源板层间CAF短路失效机理及退化时间分析

目的 掌握CAF失效机理MTTF分析方法,以便于在实际案例中实施工程优化决策,从而降低故障危害风险和寿命周期总费用。方法 以某航电电源母板CAF失效为例,基于CAF失效机理的物理化学变化时间特性模型算法,建立电压、介质间距和MTTF变化关系,以辅助工程优化决策。结果 基于仿真计算数据,形成对特定范围产品的改进和处置决策,从而限制失效危害风险的进一步扩散,降低了产品生命周期维护费用,并提升了客户满意度。结论 掌握装备常见失效机理和采取适宜的应对措施,是持续改进装备可用性、可靠性和环境适应性的必要条件。     

贵州喀斯特山区生态环境脆弱性及其生态整治

贵州是我国喀斯特地貌最发育的省份之一,属典型的生态环境脆弱区通过对人口容量、生物生产力与生物量、敏感性和承灾能力等4个方面的分析阐述了贵州喀斯特山区生态环境脆弱性的基本特征,探讨了喀斯特脆弱环境形成的自然因子和人类活动因子的影响机理,根据我国西部大开发中生态建设的要求,提出了贵州喀斯特山区脆弱生态环境的整治对策．     

基于改进RPS的共因失效模型及在安全仪表系统中的应用研究

基于安全仪表系统共因失效机理的定性分析,在单一冲击下的RPS模型基础上,以泊松分布作为冲击的先验分布,建立了多冲击下考虑共因失效的安全仪表系统可靠性模型;采用基于专家经验和估计的方法,对模型参数进行估计;并通过定量分析确定出影响系统共因失效的最大冲击因子,为降低系统共因失效对可靠性的影响提供辅助决策支持。将改进的多冲击RPS模型的可靠性分析结果与β模型和PDS模型进行比较,验证了该模型的工程准确性。     

我国废旧纺织品回收再利用的困境及其成因分析

我国是纺织品的生产大国,也是纺织品的消耗大国。在快时尚观念的影响下,纺织品更新频率越来越快,更新数量越来越大,导致废旧纺织品的回收再利用成为急需解决的问题。分析了目前废旧纺织品回收再利用的困难状况,探究了这种状况产生的原因,主要在于纺织品复杂度高、政策规制不到位、意识淡漠、回收渠道不畅等因素。     

人误因素树构建技术研究

运用人误因素辨识多视图法进行因素辨识,建立了详细的因素辨识表;把人的行为分为5个阶段,即系统状态监测阶段,目标分析阶段,方案确定阶段和行为执行阶段.分别分析各个阶段可能的人误原因及模式;以组织视图为例,根据因素辨识和人误原因及模式分析结果,阐述人误因素树的构建过程,最终得到了1个完整的人误因素树.     

矸石山的危害及自燃原因关联分析

从不同角度论述了矸石山具有的危害性,尤其是自燃矸石山对空气环境、水质和土壤的污染,通过实验分析矸石山自燃的主要影响因素,指出由于自燃矸石山的管理、治理不当所引发的矸石山坍塌和爆炸等地质灾害事故,给当今煤炭企业发展带来的不可忽视的负面影响,促使企业意识到消除矸石山危害的紧迫性和任务的艰巨性,同时为防止矸石山自燃提供了理论指导和依据。     

Arsenic residue in residential area after cleanup of pesticide illegal dumping sources in Thanh Hoa province,Central Vietnam

In Vietnam, Nicotex's site is perhaps the most infamous case of illegal disposal of toxic pesticides near residential areas. In 2013, affected villagers discovered illegal burials of around 1,000 tons of expired pesticides in the Nicotex factory. Organic pesticides were detected in illegal burial areas (IBAs) around 60 times greater than acceptable levels, but no attention was paid to contamination of metals, metalloids, and other classes of organic contaminants, which could be co-contaminants in pesticide formulation. This study assessed the contaminants remaining in the IBAs and surrounding residential areas two years after the source removal conducted in 2014. Additionally, a preliminary health risk assessment from residual contaminants was performed. Nine classes of chemicals including parental pesticides, inorganic and organic degradation byproducts, and metals and metalloids, comprising 123 chemicals were quantified in soil, sediment, and water samples from Nicotex and surrounding residential areas. Although concentrations of organic pesticides were below acceptable levels, arsenic contamination in the soil in a Nicotex IBA named NCT5 and Nap village (NV) exceeded the acceptable level. The enrichment factor and log-probability plot indicate that arsenic enrichment at NV is not from natural sources but is associated with arsenic contamination in NCT5. Arsenic may be a co-contaminant in pesticide manufacturing or an arsenical pesticide, such as monosodium methanearsonate. Arsenic found in NV was toxic arsenate for which the preliminary risk assessment yielded an unacceptable excess carcinogenic risk (1 × 10^?4). While all attention was paid to investigate and treat contamination of organic pesticides, it turns out that arsenic is the major existing threat which poses an unacceptable cancer risk in good agreement with the high cancer rate claimed by villagers near Nicotex. This justifies the need for further investigation of the extent of the arsenic contamination and restoration of the contaminated land.     

2005年中国气态α HCH的人体暴露和健康风险分析

为评估由我国大气中α HCH所导致的人体健康风险,利用CanMETOP 模拟的2005年日均α HCH大气浓度,基于吸入因子和致癌风险进行研究。结果表明年吸入因子呈东部>西部,北部>南部的特征,东中和东北部地区的吸入因子分别主要由人口密度和α HCH大气浓度贡献,东中和东南部地区的个体健康损失小于东北地区,东中和东南部地区年内逐月吸入因子分配较为均匀,而东北地区主要集中的夏季,东北地区个体致癌风险系数明显高于中部和南部。推测由其它污染物所形成的暴露风险具有类似的时空分布。加之夏季东北地区集中降水所形成的湿沉降以及气温升高等因素,使摄食暴露和皮肤接触暴露增大,东北地区人群的复合暴露风险将显著大于其它地区     

Polycyclic aromatic hydrocarbons in cigarette sidestream smoke particulates from a Taiwanese brand and their carcinogenic relevance

Polycyclic aromatic hydrocarbons (PAHs) adsorbed on cigarette sidestream smoke particulates (CSSPs) have been regarded as important contributors to lung carcinogenesis in never smokers. However, limited information is available on PAH levels in cigarette sidestream smoke. Here we determine the concentrations of 22 PAHs, including 16 US EPA priority PAHs, in CSSPs generated from a high market-share domestic brand in Taiwan. Five of the 22 PAHs are undetectable. The remaining 17 PAHs constitute about 0.022% of the total mass of CSSPs. Near one fifth of the PAH mass come from IARC group 1 and group 2 carcinogens. Carcinogenic potency is equivalent to 144 ng benzo[a]pyrene per cigarette converted according to potency equivalency factors (PEFs). The CSSP condensate could activate AhR activity and induce AhR target gene expression. High concentrations of CSSPs also exhibited AhR-independent cytotoxicity. However, mixing the 17 PAHs as the composition in the CSSP condensate could not reconstitute either capacity. Since AhR activation and cytotoxicity are important mechanisms underlying carcinogenic potency, the results suggest that other component compounds play a more active role in carcinogenesis. The approach of individual PAH profiling plus PEF conversion commonly used in risk assessment is likely to underestimate the risk caused by environmental cigarette smoke exposure.     

Using data linkage to assess the impact of motorized recreational vehicle-related injuries in Ohio

Problem

Motorized recreational vehicle (MRV)-related injuries can result in severe medical and financial consequences. The objective of this study was to describe the epidemiology, and clinical and financial impact of MRV-related injuries in Ohio.

Method

Probabilistically linked statewide Emergency Medical Services (EMS) and hospital (inpatient and emergency department) data for 2003 and 2004 were examined. Record pairs with a MRV-related E-code (E821-E823, E825) were included in this study.

Results

There were 2,893 patients with MRV-related injuries, who had linked EMS and hospital records, resulting in more than $15 million in hospital charges and 1,921 inpatient days of hospitalization. The male-to-female ratio was nearly 4:1, and 19% were younger than 16. Almost 82% of cases were not wearing a helmet; there was a trend of decreasing helmet use with increasing age. Mean (SE) inpatient hospital charges and length of stay (LOS) were $22,218 ($1,290) and 3.8 (0.2) days, respectively. The mean (SE) Injury Severity Score (ISS) for inpatients was 9.2 (0.4). Individuals injured on a street/highway were 3.20 times more likely to sustain an ISS ≥ 16 (95% CI: 1.03, 9.88; p = 0.044) and 3.05 times more likely to sustain a traumatic brain injury (TBI) (95% CI: 1.17, 7.94; p = 0.024) than those who were injured at a place designated for sport or recreation. Children aged 12 to 15 and young adults aged 16 to 25 were 2.47 and 2.14 times more likely, respectively, to sustain a TBI than adults aged 36 or older (aged 12 to 15: 95% CI: 1.13, 5.38; p = 0.024; aged 16 to 25: 95% CI: 1.26, 3.64; p = 0.005). Higher ISS was associated with both higher total charges (p < 0.001) and longer LOS (p < 0.001).

Discussion

This study demonstrates that MRV-related injuries are an important public health problem in Ohio, with a substantial clinical and financial impact.

Impact on Industry

Enactment and enforcement of statewide MRV safety legislation and training of MRV users offer valuable opportunities to prevent these costly injuries.