煤层透气性系数的优化和简化计算方法

煤层透气性系数是用以考察保护层开采效果和设计瓦斯抽采系统的重要参数之一,钻孔径向流量法是求取该系数最常用的算法。利用理论推导和图形分析方法,探讨流量准数、时间准数、煤层透气性系数与参数A,B间的关系。在此基础上,针对科研工作和现场管理的实际情况,提出求解透气性系数的2种新算法及其算法流程,并对时间准数-参数A,B函数关系中的间断点问题进行讨论和分析,解决此区间内求解透气性系数相应计算公式等问题。理论和实例分析表明:算法1在不更改最终计算公式和结果的前提下,省去了繁琐的试算过程,既保证了可靠性也优化了计算流程;算法2以稍减精度的代价对计算流程进行进一步的简化,其结果仍有较高精度。     

高层学生公寓防火体系构建

归纳总结学生高层公寓火灾伤亡事故致因因素,利用事故树分析法对其进行定性分析,得出最小径集,找出控制事故发生的途径,并利用“瑟利模型”建立防火体系,得到此类火灾事故防控措施,即一要通过培训和教育的手段,提高人感觉火灾危险的敏感性,使人处于安全状态并能够迅速、敏捷、正确地做出行为响应;二要保证物处于安全状态,确保电气设备、建筑物本质处于安全状态,并使建筑物能发挥性能化灭火作用,能在一定程度上控制火势,为疏散争取时间.本文能为高校高层学生公寓预防和控制火灾伤亡事故工作提供一定的借鉴作用.     

Emergency preparedness through game playing

The lack of emergency preparedness in Mauritius has been the cause of many tragedies. Our approach to tackle this problem was by developing an emergency preparedness game layered and fused with a disaster warning and guidance system that emanates clarity to the unfathomable bearings of emergencies and natural disasters. The emergency preparedness game is based on a selection of diverse real life-threatening difficulties that entail different strategies aimed at bettering the survival instincts of users. It uses story-telling scenarios along with in-game footnotes that yield directives on how to brave fierce and unpredictable calamities. The game reinforces a sense of self-composedness and suppressing untimely fears of users in horrendous circumstances. With regard to the warning system, it unremittingly feeds users with notifications during emergencies, that encases shortest escape routes to lead them to safe locations via a fully functional GPS map. This application brings some novelties that are virtually non-existent in related applications. For instance, this application includes a warning and guidance system, a 3D scenario game to prepare its users for disasters, an interactive survival toolkit selection, an SMS rescue feature and a mass notification system via the web.     

Epidemiology of alcohol and drug screening among pedestrian fatalities in the United States, 2014–2016

Objective: U.S. pedestrian fatalities increased by 25% between 2010 and 2015. Risk factors include distractions, the built environment, urbanization, economic variables, and weather conditions. Of interest is the role of alcohol and drugs in premature death among pedestrians. This study sought to explore the prevalence of substance use screenings among pedestrian fatalities in the United States between 2014 and 2016.

Methods: Data were collected from the Fatality Analysis Reporting System provided by the NHTSA. Pedestrian crash variables included demographics as well as information regarding alcohol or drug testing status. Frequency and cross-tabulation tables were constructed to assess the prevalence of screening by person, place, and time. Log-linear analyses were completed to explore age, race, and sex differences. A 3-year examination period was used to control for yearly fluctuations and to incorporate an increasing trend in cases.

Results: Pedestrian fatalities accounted for 84% of all deaths among vulnerable road users during the examination period. Those most at risk were white males between the ages of 45 and 64. Over all states, 74.7% of fatalities were tested for alcohol and 67.1% were tested for drugs; further, 66.5% of cases were tested for both alcohol and drugs and 24.8% were tested for neither substance. Cases screened for both alcohol and drugs ranged from 2.9% in North Carolina to 95.7% in Nevada and those testing for neither substance ranged from a high of 68.9% in Indiana to a low of 1.1% in Maryland. Log-linear regression revealed significant differences in alcohol screening by age and race but not by sex. Differences in drug screening were not identified for any demographic variable. Fatalities tested for alcohol were significantly more likely to be tested for drugs; only 8.2% were screened solely for alcohol and 0.05% were screened for drugs alone.

Conclusions: Preventive strategies become more important as pedestrian crashes and fatalities increase. Risk reduction in the form of policy change, alterations to the built environment, or interdisciplinary approaches to injury prevention is dependent upon best evidence supported in part by more deliberate and consistent screening.     

Collecting representative dust samples: A comparison of various sampling methods in underground coal mines

Former methods used in the U.S. to assess hazardous and explosible coal dust date back to the 1950s. As mining technologies advanced, so too have the hazards. Given the results of the recent coal dust particle size survey and full-scale experimental mine explosion tests, the National Institute for Occupational Safety and Health (NIOSH) recommended a new minimum standard, in the absence of background methane, of 80% total incombustible content (TIC) be required in the intake airways of bituminous coal mines, replacing the previous 65% TIC requirement. Most important to monitoring and maintaining the 80% TIC is the ability to effectively collect and analyze representative dust samples that would likely disperse and participate in dust explosion propagation. Research has shown that dust suspended on elevated surfaces is usually finer, more reactive, and more readily dispersible while floor deposits of dust are generally coarser and more difficult to disperse given the same blast of air. The roof, rib, and floor portions of the dust samples were collected and analyzed for incombustible content separately and the results were compared to a band sample of the roof, rib, and floor components. Results indicate that the roof and rib dust samples should be kept separate from floor dust samples and considered individually for analyses. The various experimental collection methods are detailed along with preferred sampling approaches that improve the detectability of potentially hazardous accumulations of explosible dust.     

E‐commerce trade in invasive plants

Biological invasions are a major concern in conservation, especially because global transport of species is still increasing rapidly. Conservationists hope to anticipate and thus prevent future invasions by identifying and regulating potentially invasive species through species risk assessments and international trade regulations. Among many introduction pathways of non‐native species, horticulture is a particularly important driver of plant invasions. In recent decades, the horticultural industry expanded globally and changed structurally through the emergence of new distribution channels, including internet trade (e‐commerce). Using an automated search algorithm, we surveyed, on a daily basis, e‐commerce trade on 10 major online auction sites (including eBay) of approximately three‐fifths of the world's spermatophyte flora. Many recognized invasive plant species (>500 species) (i.e., species associated with ecological or socio‐economic problems) were traded daily worldwide on the internet. A markedly higher proportion of invasive than non‐invasive species were available online. Typically, for a particular plant family, 30–80% of recognized invasive species were detected on an auction site, but only a few percentages of all species in the plant family were detected on a site. Families that were more traded had a higher proportion of invasive species than families that were less traded. For woody species, there was a significant positive relationship between the number of regions where a species was sold and the number of regions where it was invasive. Our results indicate that biosecurity is not effectively regulating online plant trade. In the future, automated monitoring of e‐commerce may help prevent the spread of invasive species, provide information on emerging trade connectivity across national borders, and be used in horizon scanning exercises for early detection of new species and their geographic source areas in international trade.     

Factors affecting use and nonuse of child safety car seats in Gorgan,Iran

Objective: Motor vehicle accidents, which are among the main causes of child mortality in Iran and the Middle East, impose staggering costs for the community. Ignoring use of safety devices for children in most motor vehicle crashes will lead to death or serious injury. Because few studies have been performed on effective and predictive factors regarding use of child safety seats, the purpose of this study was to examine the factors affecting the use and nonuse of child safety seats, along with the factors that can facilitate how a child safety seat is used.

Method: This study was conducted in the urban area of Gorgan using a questionnaire. Through random selection, 204 parents with at least one child, aged 8?years or younger, reported their knowledge about the benefits of using a child safety seat.

Results: The results showed that 80% of parents never use a child safety seat, and 13% always use a child safety seat. More than 93% thought that it was necessary to make usage of the child safety seat obligatory. In addition, 80% of parents believed that a child safety seat prevents children from injury in crashes. In addition, 38% of parents were not aware of child safety devices and child safety, less than 20% said that they did not use a child safety seat because their spouse did not support its use, and 28% of them thought that a child safety seat does not affect the safety of the child. In general, 91% of parents reported that if child safety seat use were mandated, the frequency of use would increase. A law on the use of child safety seats is a very important variable in their use, which can enhance the chance of using a child safety seat by 6.5 times.

Conclusion: Special instructions should be developed to create incentive strategies for using a child safety seat. Mandating the use of a child safety seat, equipping cars with a child safety seat, encouraging children to use it, and providing continuous education and training are important factors for increasing the use of child safety seats.     

采空区注超临界CO2防灭火试验研究

为研究超临界CO₂注入采空区防灭火的规律,自主研制了产生超临界CO₂和模拟采空区遗煤自燃升温试验系统,得到了不同温压条件下超临界CO₂注入采空区前后不同监测点的温度、O₂和CO浓度变化数据信息。试验结果表明:注入采空区的超临界CO₂发生相变,有序结构急速失序,大量吸收热量,采空区内的煤体、空气温度随时间呈线性快速下降规律,其降温能力是气态N₂的10倍;超临界CO₂在自燃发火煤体中的强渗透扩散特性,使自燃煤体快速惰化,防灭火效率高;停止注入后,小范围回温符合反二次函数特征;高压力超临界CO₂相对于低压条件,防灭火性能更佳;超临界CO₂是1种降温降氧能力显著,且输送性能优良的采空区新型防灭火材料,超临界CO₂防灭火效果优于气态N₂。     

中国土地盐碱化及其防治对策研究

中国盐碱地面积为３６３０万ｈｍ２，土地盐碱化是农业生态环境退化的重大问题之一。土地盐碱化治理和预防对中国干旱、半干旱和半湿润地区农业生态系统退化防治、农业生态环境保护和未来食物安全性具有非常重要的实践意义。本文简要评述了我国土地盐碱化的历史及发展趋势以及土地盐碱化可能造成的土地面积、生产力和经济损失；在对土地盐碱化发生和发展的技术和社会经济原因，以及现有技术、管理、政策和法律法规进行系统评述的基础上，提出了我国土地盐碱化防治的区域战略、技术政策、管理政策、法律法规及经济激励手段。     

Environmental health in minority and other underserved populations: Benign methods for identifying lead hazards at day care centres of New Orleans

This study tests the hypothesis that exterior sources of lead dust are more important than interior sources in the route of exposure of children. Benign field methods were used to distinguish between potential and actual lead exposure problems. Utilising hand wipe and surface wipe techniques, hand and environmental samples were obtained from selected day care centres at different locations within New Orleans. Previous research has shown that soil lead is determined by location within the city. Private and public day care centres were selected from inner and outer city areas to estimate the extent of hand lead exposure. To measure and identify the extent of environmental lead exposure, hand wipes were taken before and after playing outdoors. Results of preliminary findings show that outdoor lead dust is a more potent contaminant of hands than indoor lead dust. An association was found between the amount of lead on children's hands after playing outdoors and the lead content in the exterior dust and soil. Although two girls out of forty children had exceptionally high hand lead quantities after playing outdoors, in general, boys have higher hand lead levels than girls. The private inner-city day care centre had a severe contamination problem in its outdoor play area. By contrast, the outdoor play area of the public inner city day care centre is of such a high quality that the quantity of lead dust is independent of location in the city.