Hazardous Air Pollutants (HAPs) and their Effects on Biodiversity: An Overview of the Atmospheric Pathways of Persistent Organic Pollutants (POPs) and Suggestions for Future Studies

Atmospheric change comprises many phenomena, namely climate change, acidic deposition, stratospheric ozone depletion, SMOG, increasing trend of suspended particulate matter, and hazardous air pollutants (HAPs). Among HAPs, a particular group of Persistent Organic Pollutants (POPs), such as some organochlorine pesticides, has shown a variety of toxic effects, altering the biodiversity of many ecosystems. Because of their persistence in the environment, and of their long range transport, the study of the global cycle of POPs is important in understanding how they can affect biodiversity. This can be accomplished by coupling different approaches: toxicity and ecological studies, emission estimates, and the use of global models.     

Lake ecosystem responses to rapid climate change

In this paper, we examine the consequences of rapid climate change on lake ecosystems in terms of two main effects: variability effects and magnitude effects. How these factors influence life history selection is considered by focusing upon body size as a quantifiable and strong correlate of life history variation (Pianka 1970, McNab 1980, Charnov 1991). We then consider the relationship between the concept of biological diversity and the diversity of life history strategies in the context of rapid climate change.     

天津市道路车流量特征分析

车流量是移动源和道路扬尘排放清单计算的一个重要参数,直接影响排放清单的不确定性.为了解天津市道路车流量特征,通过人工摄录法获取天津市一年四季5种不同类型共9条道路的车流量及车型分布信息,并对其特征进行分析.结果表明:天津市不同类型道路之间车流量总体上呈快速路（8 790辆/h）>主干道（4 077辆/h）>外环线（3 335辆/h）>次干道（2 461辆/h）>支路（1 507辆/h）的特征;冬季车流量最大,而春、夏两季相对较小.各类型道路车流量占比最大的车型均为轻型车（76.88%~90.71%）,中型车（5.31%~11.80%）次之,重型车（3.20%~11.31%）最少;快速路和外环线工作日的车流量大于非工作日,并且差异具有统计学意义,呈"周末效应".研究显示:次干道和支路车流量与主干道车流量呈线性相关,在后续进行道路扬尘和移动源清单编制时,可以考虑通过将主干道车流量与次干道、支路拟合的方式减小工作量;此外,主干道、次干道和支路的早高峰,上、下午平峰,中午和晚高峰的车流量差异不大,可将一天划分为白天、夜晚和凌晨3个时段进行统计,从而节约时间和成本.      

Identifying stream temperature variation by coupling meteorological,hydrological, and water temperature models

In this study, we demonstrate a physically based semi-Lagrangian water temperature model known as the River Basin Model (RBM) coupled with the Variable Infiltration Capacity (VIC) hydrological model and Weather Research & Forecasting Model in the Mississippi River Basin (MRB). The results of this coupling compare favorably with observed water temperature data available from six river gages located in the MRB. Further sensitivity analysis indicates that the mean water temperatures may increase by 1.3, 1.5, and 1.8°C in northern, central, and southern MRB zones under a hypothetical uniform air temperature increase of 3.0°C. If air temperatures increase uniformly by 6.0°C in this scenario, then water temperatures are projected to increase by 3.3, 3.5, and 4.0°C. Lastly, downscaled air temperatures from a global climate model are used to drive the coupled VIC and RBM model from 2020 to 2099. Average stream temperatures from 2020 to 2099 increase by 1.0 to 8.0°C above 1950 to 2010 average water temperatures, with non-uniform increases along the river. In some portions of the MRB, stream temperatures could increase above survival thresholds for several native fish species, which are critical components of the stream ecosystem. In addition, increased water temperatures interact with nutrient loadings from sources throughout the MRB, which is expected to exacerbate harmful algal blooms and dead zones in the Gulf of Mexico.     

低温取芯过程热传递方式的数值模拟和实验研究

为了研究热量在低温取芯过程中传递的方式,以型煤为研究对象,使用自制低温取芯模拟装置,通过实验并结合数值模拟,对低温取芯过程热量传递方式进行研究,进而分析煤芯温度的变化规律。研究结果表明:甲烷的存在降低了煤样的热交换速率,使煤芯温度变化滞后于煤样罐壁温度变化;煤体内部温度分布存在差异,煤样中心轴线不同半径处的圆柱面构成变温过程的等温面,在降温过程,热量沿径向由煤样内部向外部传递,升温过程,热量沿径向由外部向内部传递;低温取芯过程热量传递同时存在3种方式:热传导、热对流,煤体表面与罐体内壁表面之间的热辐射,以热传导方式为主。     

基于T-P模型的高低温环境型煤对甲烷吸附性能预测

为预测深部或浅部煤层不同温度和不同压力条件下的吸附等温线,选用型煤以高低温试验装置为依托,测试了温度为293.15,273.15,253.15 K的吸附等温线。基于T-P模型,利用等温吸附曲线对公式中的参数进行了合理的求解,探讨了一种简单的煤对瓦斯吸附等温线预测方法。研究表明:同一吸附平衡压力下,温度越低,煤的瓦斯吸附量越大;ε－ω吸附特征曲线与温度无关,呈现对数的形式;参数m和拟合度R2满足抛物线的关系,存在拟合效果最好时的参数m值。采用T-P模型预测得到的吸附等温线与实测的吸附等温线无论是趋势还是定量结果均十分吻合,其相对误差不超过5%。     

供风量对褐煤自燃极限参数的影响研究

为研究不同供风量对褐煤自燃特性的影响规律,选取平庄瑞安煤矿褐煤作为试验煤样,利用程序升温试验和气相色谱仪,研究低温氧化阶段不同供风量条件下褐煤自燃极限参数与温度、供风量之间的变化规律。结果表明:温度在40~120℃时,随着供风量增大,褐煤的最小浮煤厚度和下限氧浓度降低,上限漏风强度增加;温度在120~200℃,供风量为40~80 mL/min和160~200 mL/min时,随着供风量的增加,其最小浮煤厚度和下限氧浓度增加,上限漏风强度减少;供风量为80~160 mL/min时,在供风量增大的情况下,褐煤的最小浮煤厚度和下限氧浓度降低,上限漏风强度增加;随着供风量减小,煤样临界点温度降低。     

大型油罐火灾爆炸危害范围研究

针对大型油罐火灾爆炸对人员伤亡危害范围的问题,采用PHAST软件模拟定量分析了外部环境（风速、大气稳定度、空气湿度）、初始条件（泄漏点离地高度、泄漏孔直径）和其他因素（防火堤面积）对火灾爆炸伤亡半径的影响,根据模拟结果拟合了外部环境和初始条件与池火灾和蒸气云爆炸危害范围的关系式。结果表明:在相同条件下,软件模拟与实验结果误差较小,该研究具有可信性;池火灾危害范围随风速、泄漏点离地高度、泄漏孔当量直径和防火堤面积的增加而增加,而与大气稳定度的关系不大;蒸气云爆炸危害范围随风速的增加而降低,随大气稳定度和泄漏孔当量直径的增加而增加,而与泄漏点离地高度和空气湿度影响不大;拟合得到的外部环境和初始条件与池火灾和蒸气云爆炸危害范围的关系式可为大型油罐火灾爆炸事故中相关作业人员的应急撤离提供决策参考。     

冷板冻结物理模拟试验研究

为了提升地铁工程盾构管片破损抢险应急救援能力,在广佛线某区间地铁隧道管片冻结封水工程中使用矩形截面的外置冻结器—冻结冷板。采用物理模拟试验,对混凝土结构外敷冷板冻结形式下的冻结规律进行系统研究,研究单排冷板、双排冷板及冻结盘管的冻结温度场变化规律,分析不同布置形式下冻结壁的界面、主面温度分布特征。研究结果表明:在冷板冻结形势下,主、界面温度分布曲线在浅部呈对数曲线形式,随深度的增加逐渐过渡成线性分布,冻结器与冻结介质的热交换面积大小对冻结效果影响比重大,适当的布置形式能大大提高冻结效率和效果。冷板冻结形式可以有效加强土层与混凝土结构交接面的冻结效果,提高交界面上胶结强度,提高冻结施工安全。     

煤矿通风机电机温度高故障研究与解决应用

经过充分调研,结合理论分析,从选型、设计制造、试验、运行维护4个方面全面分析煤矿通风机电机温度高的故障原因,从选型、设计、立法与标准制定、执法等方面提出了具体的解决措施,最后结合具体实例,应用提出的措施很好地解决了煤矿通风机电机温度高的故障。