植物滞尘分析及其数学表达模式

在植被的树冠结构分析、植物滞尘机理和粉尘沉降速度半经验公式的基础上,建立了植物滞留大气颗粒物的数学表达式。利用Beta功能函数φθ(X)、叶面的投影面积、叶面积密度a(z)、叶投影面积分布参数Kx、Kz等描述不同植被冠层的结构特征,并分析了冠层内的空气动力变化和树冠内气溶胶的平衡公式。借鉴Slinn的颗粒物沉降半经验公式、Petroffa等的阔叶滞尘计算模式,植物滞尘沉降通量数学表达式以树冠中树叶的位置为变量、由颗粒物在单片树叶上的各物理机制的沉降速度积分而成。结合国内外植物上沉降速度的试验结果和植物滞尘沉降通量公式的分析结果对影响植物滞尘的主要因素进行了比较分析。     

济南市土壤酸沉降承压度研究

将承载力理论应用到酸沉降研究中,建立了土壤酸沉降承载力评价方法,并对济南市进行了实证分析.在地理信息系统(GIS)支持下,以遥感数据为数据源,在确定土壤外界压力及内部缓冲能力的基础上,计算了土壤酸沉降承压度.以承压度作为评价指标对济南市土壤酸沉降承载状况进行了评价.将承压度大于1定义为超载,结果表明,2005-2010年济南市S沉降超载区域大多分布在南部部分植被区域及北部部分耕地区域,超载的主要土壤类型为潮土;N沉降超载区域主要分布在南部部分植被区域,各主要土壤类型N沉降承压度平均值均小于1.评价方法借助于遥感数据,能够满足区域土壤酸沉降承载力评价空间和时间尺度上的需求,是对土壤酸沉降常规研究方法的补充.     

7FA临界灭火浓度的测定及7FA/BTP协同灭火作用研究

作为氢氯氟烃、氢氟烃和全氟烃的理想替代物,七氟环戊烷(7FA)因其具有环境友好性和环状结构而极具发展潜力.首先构建了临界灭火体积分数测定平台,采用杯式燃烧器法测得7FA熄灭乙醇火焰的临界灭火体积分数为8.4％.其次,为了规避其灭火体积分数稍高的缺点,将7FA和一溴三氟丙烯(BTP)按照一定的物质的量比进行了混合,结果表明,在7FA中加入少量的BTP可以显著提高其灭火能力并将其临界灭火体积分数降低到6％以下.最后,在此试验基础上对构建的理论预测模型的可靠性进行了验证,得出7FA与BTP之间存在协同灭火作用.     

Evaluation of Vehicle-Based Crash Severity Metrics

Objective: Vehicle change in velocity (delta-v) is a widely used crash severity metric used to estimate occupant injury risk. Despite its widespread use, delta-v has several limitations. Of most concern, delta-v is a vehicle-based metric which does not consider the crash pulse or the performance of occupant restraints, e.g. seatbelts and airbags. Such criticisms have prompted the search for alternative impact severity metrics based upon vehicle kinematics. The purpose of this study was to assess the ability of the occupant impact velocity (OIV), acceleration severity index (ASI), vehicle pulse index (VPI), and maximum delta-v (delta-v) to predict serious injury in real world crashes.

Methods: The study was based on the analysis of event data recorders (EDRs) downloaded from the National Automotive Sampling System / Crashworthiness Data System (NASS-CDS) 2000–2013 cases. All vehicles in the sample were GM passenger cars and light trucks involved in a frontal collision. Rollover crashes were excluded. Vehicles were restricted to single-event crashes that caused an airbag deployment. All EDR data were checked for a successful, completed recording of the event and that the crash pulse was complete. The maximum abbreviated injury scale (MAIS) was used to describe occupant injury outcome. Drivers were categorized into either non-seriously injured group (MAIS2?) or seriously injured group (MAIS3+), based on the severity of any injuries to the thorax, abdomen, and spine. ASI and OIV were calculated according to the Manual for Assessing Safety Hardware. VPI was calculated according to ISO/TR 12353-3, with vehicle-specific parameters determined from U.S. New Car Assessment Program crash tests. Using binary logistic regression, the cumulative probability of injury risk was determined for each metric and assessed for statistical significance, goodness-of-fit, and prediction accuracy.

Results: The dataset included 102,744 vehicles. A Wald chi-square test showed each vehicle-based crash severity metric estimate to be a significant predictor in the model (p < 0.05). For the belted drivers, both OIV and VPI were significantly better predictors of serious injury than delta-v (p < 0.05). For the unbelted drivers, there was no statistically significant difference between delta-v, OIV, VPI, and ASI.

Conclusions: The broad findings of this study suggest it is feasible to improve injury prediction if we consider adding restraint performance to classic measures, e.g. delta-v. Applications, such as advanced automatic crash notification, should consider the use of different metrics for belted versus unbelted occupants.     

基于稳定风场的架空天然气管道泄漏数值模拟

针对架空管道天然气泄漏问题,考虑管道自身对泄漏扩散的影响,利用计算流体力学(CFD)软件建立天然气管道三维泄漏模型,为提高模拟可信性和合理性,先对计算流域风场进行稳态模拟,再对天然气泄漏扩散过程进行瞬态模拟,分析天然气泄漏扩散规律及风速对泄漏扩散的影响。结果表明:在稳态风场模拟中,管道附近风场受管道影响十分明显,管道上下侧面风速极高;在瞬态天然气泄漏扩散模拟中,天然气泄漏初期的扩散受风速影响明显,验证了先进行稳态风场模拟的必要性,泄漏扩散达到稳定状态后出现气云沉降、单侧分布、尾部分叉、风速影响扩散距离的特征;同等风速条件下,较小浓度边界扩散范围大,达到稳定所需时间短,同等浓度边界条件下,风速与扩散影响面积和浓度边界达到稳定所用时间成反比。     

南京北郊冬季大气粗细颗粒物中PAHs来源解析

为研究南京冬季大气颗粒物中PAHs来源情况,利用FA-3型气溶胶采样器从2007年11月20日到12月30日在南京郊区分昼夜采集气溶胶样品,并用GC-MS对16种优控PAHs浓度进行定量分析,采用PCA法对其来源进行解析.结果表明,南京冬季细颗粒物中PAHs浓度明显高于粗颗粒物中PAHs浓度,单种类PAH浓度表现出昼夜差异,日间低分子量PAHs含量高于夜间,而夜间高分子量PAHs浓度则相对较高;主成分分析对PAHs源解析结果表明,南京北郊大气颗粒物中PAHs主要来源为机动车尾气、燃煤源、焦化源、天然气燃烧和烹调源等,粗细颗粒物中PAHs排放源差异明显,细颗粒物部分表现出明显的昼夜差异,同时,外来源和不确定源占有较大比重.     

Positive psychology in education for sustainable development at a primary-education institution

The present global environmental crisis is demanding serious rather than superficial changes within the cultural assumptions of human-to-human and human-to-nature relationships. In this sense, education is one of the strongest tools to model our future and a key factor of cultural change. One of the principal aims of Education for Sustainable Development (ESD) is to develop cognitive and affective skills that affect people's values, such as empathy and critical thinking. Together with compromise and responsibility towards a group, it is possible to build new values and ways to interact with both people and the environment. In the present study we used positive psychology principles in creating teaching interventions to empower empathy and critical thinking through an ESD programme at a Chilean primary school. The results show that an intervention of this kind helps to harmoniously build reflective thinking and empathy within students. This enables them to achieve important changes in their disposition to make sound personal and environmental decisions, and prepares them to positively meet imposing present and future challenges.     

广西陆上风电场开发存在的环境问题及对策研究

广西从保证能源安全,减少污染物排放,保护环境,满足低碳经济社会发展对能源的需要,将风电项目作为新能源项目重点推进.广西陆上风电场大部分位于水源涵养和生物多样性保护生态功能区、水土流失重点防治区等敏感区,通过分析目前风电规划、建设在选址、生态环境破坏方面存在的问题,对广西陆上风电场开发建设、环境管理提出相关建议.建议对广西风能资源开发所取得环境经济效益进行全面评估,指导推进广西陆上风电场的开发建设.     

Null-Hypothesis Significance Testing and the Critical Weight Range for Australian Mammals

Abstract:  The critical weight range hypothesis for Australian terrestrial mammals states that species in the intermediate size range 35–5500 g are particularly susceptible to extinction. In a 2001 study Cardillo and Bromham found no statistically significant evidence for this hypothesis and suggested that research should instead focus on why small species are resistant to extinction. We used a similar data set of body sizes of Australian mammals grouped by conservation classification, but we used test statistics (mean deviation above and below the median body size) that are more statistically powerful than those of Cardillo and Bromham (quartiles, maxima, and minima of body size distributions). We found strong evidence in favor of the critical weight range hypothesis: the body size distribution of threatened species was more clustered toward the median body size from above and below. This pattern was statistically significant at the continental scale and in the arid zone, but not in the mesic zone. Confusing statistical significance with evidence of no effect, as Cardillo and Bromham did, can have negative implications for conservation biology because it can result in failure to act when action is warranted or provision of incorrect advice that affects policy and planning decisions.