Flammability of heat transfer fluid aerosols produced by electrospray measured by laser diffraction analysis

Accidental release of pressurized high flash point heat transfer fluids can result in fire and explosion hazard scenarios in the process industry. An experimental investigation on ignition of aerosols of a heat transfer fluid is carried out, and characterization of aerosol and its ignition process by non-intrusive laser diffraction technique is reported. Propagation speed of the aerosol combustion flame front as analyzed from the laser diffraction measurement agrees with high-speed visual camera observation. Flammability of the aerosol, which is based on the chances of the global flame appearance in the aerosol, is mainly controlled by aerosol droplet size and the droplet volume concentration.     

城市生活垃圾的生命周期管理

根据国际标准化组织１９９７ 年颁布的ＩＳＯ１４０００ 环境管理体系“生命周期评价—原则与框架”,本文对可持续城市生活垃圾生命周期管理进行研究,指出城市生活垃圾应在环境可持续性、经济可负担性及社会可接受性的原则基础上,通过垃圾的减量化、无害化、资源化和社会化管理,实现城市可持续发展的管理目标     

基于百度指数的长江三角洲虚拟旅游流流动特征和影响因素分析

旅游流是游客在空间区域内的集散过程所带来的一系列经济社会发展效应,是旅游系统的神经中枢和纽带.传统旅游流研究多集中于现实旅游流,对虚拟旅游流涉及较少,数据获取多依靠调查问卷与景区提供,具有局限性.文章基于百度指数,在保证数据容量与准确度的基础上以长江三角洲为研究对象,构建O-D虚拟旅游流矩阵探究区域虚拟旅游流流动特征,并利用地理加权回归(GWR)模型从流入市域、流出市域两方面,分析不同市域的虚拟旅游流影响因素.结果 表明:(1)长江三角洲虚拟旅游流空间分布不均,流动性较强,形成以合肥、南京、苏州、杭州、上海为核心节点的放射状网络.(2)A级景区数量、住宿和餐饮业从业人员以及公路里程可以较好的解释流入虚拟旅游流市域分布.其中,A级景区对流入虚拟旅游流影响最为显著,住宿和餐饮业的发展对长江三角洲西北部虚拟旅游流的流入具有推动力,而公路里程对整个长江三角洲流入虚拟旅游流影响最小.(3)私人汽车拥有量、社会消费品零售总额、互联网宽带用户接入量对流出虚拟旅游流有较强的影响.社会消费品零售总额代表的经济因素是市域虚拟旅游流流出的决定因素,经济越发达的区域,人们的出游意愿越强烈,也更愿意利用网络抓取旅游信息流追求高质量旅游出行行为.     

三峡消落带沉积物-大气界面汞交换通量及其影响因素

应用动力通量箱(Dynamic Flux Chamber,DFC)与高时间分辨率的RA-915+自动汞分析仪联用技术,在消落带沉积物出露期,野外现场监测沉积物-大气界面汞交换通量,同时对其影响因素进行了分析。结果表明:三峡库区消落带沉积物-大气界面汞交换通量范围为-6.80±12.35~28.17±36.17 ng/(m2·h)晴天库区消落带沉积物-大气界面汞交换通量表现出相同的变化趋势,即从早晨开始沉积物-大气界面汞的交换通量逐渐增加,到正午左右达到峰值,之后交换通量逐渐减小,但阴天这一趋势不明显。暖季白天沉积物-大气界面汞交换通量都以释放为主,冷季白天则以沉降为主。暖季晴天,沉积物-大气汞交换通量与气温、沉积物温度、光照强度呈显著正相关关系,与相对湿度呈显著负相关关系。无论晴天还是阴天,大气汞浓度都与沉积物-大气汞交换通量呈负相关关系。白天,光照强度和大气汞浓度是影响消落带沉积物/大气界面汞交换通量的主要因素,而在夜间,沉积物温度和大气汞浓度是其主要影响因素。     

恩施地区生态足迹和生态承载力评价

以恩施地区2010年统计数据为依据,对其2010年的生态足迹、生态承载力、生态盈余进行计算和分析,并将生态足迹、生态承载力、生态盈余和万元GDP生态足迹分别与恩施地区贫困村分布密度进行空间耦合。研究表明：（1）恩施地区人均生态盈余为0467 hm2,人均生态承载力为0947 1 hm2,人均生态足迹为048 hm2;（2）贫困村分布密度最高的来凤县、建始县人均生态盈余很少,而贫困村分布密度最低的利川市、咸丰县、宣恩县、鹤峰县,人均生态足迹最高和最低的县分别是咸丰县、宣恩县,鹤峰县的生态承载力最高,人均生态盈余最高的是宣恩县、鹤峰县,万元GDP生态足迹最高和最低的分别是利川市,巴东县;（3）通过生态足迹的研究,提出了恩施贫困地区需放大生态比较优势,〖JP2〗因地制宜,努力将生态盈余转化为直接的经济增长,使之能够有效的帮助贫困地区脱贫致富     

基于遥感反演长江中游地区悬浮泥沙研究

悬浮泥沙定量研究对于调查长江的水质、地貌、生态环境等起着至关重要的作用。以长江中游武汉地区2012~2013年14幅不同时相的Landsat ETM+遥感影像为主要数据源,结合野外采样悬浮泥沙浓度数据,分析了悬浮泥沙遥感定量反演方法,数据处理中针对ETM+SLC OFF影像缝隙问题,采用自适应局部回归匹配算法（ALR）进行影像自动恢复处理,在波段选择中对悬浮泥沙浓度和光谱反射率数据进行相关性分析,并运用传统关系建模方法和高斯模型方法对比,比较悬浮泥沙定量反演模型,利用实测验证数据对反演模型精度进行评估。研究结果表明：（1）ALR可以有效的获取悬浮泥沙敏感波段的遥感光谱反射率;（2）ETM+Band3悬浮泥沙浓度的高斯模型相关系数最高,通过对比得到模型反演的验证精度较高,研究证明遥感定量反演适合于长江流域武汉段泥沙含量大范围监测     

Short-term effects and economic burden assessment of ambient air pollution on hospitalizations for schizophrenia

Environmental Science and Pollution Research - The evidence on the health and economic impacts of air pollution with schizophrenia is scarce, especially in developing countries. In this...     

What are the disease burden and its sensitivity analysis of workers exposing to Staphylococcus aureus bioaerosol during warm and cold periods in a wastewater treatment plant?

Environmental Science and Pollution Research - Biological treatment in wastewater treatment plants releases high amounts of pathogenic bioaerosols. Quantitative microbial risk assessment is a...     

A novel sigma coordinate system to simulate abrupt changes of underwater terrain in a hydrodynamic model: application to Lake Mead,USA

The sigma (SIG) coordinate system in ocean circulation simulation models results inevitably in horizontal pressure gradient error. This problem also emerges in models of deep lakes or reservoirs with the same characteristics of underwater terrain mutation. SIG coordinates reflect vertical relative stratification but cannot be used to calculate horizontal pressure gradient force in places with drastic topographic changes; this results in vertical water temperature and circulation errors. In deep lakes or reservoirs, differences in water density caused by the temperature difference between upper and lower water bodies is the primary cause of thermal stratification phenomena. Lake Mead was used as a case study on steep topography based on Environmental Fluid Dynamics Code (EFDC) model in this study. SIG coordinates result in close agreement between the calibrated temperature time series at the top and middle water layers, but disparity in the bottom water layer. The error emerges in the horizontal pressure gradient error due to the SIG coordinate transformation. Neither increasing the vertical resolution nor adjusting the horizontal viscosity coefficient resolve this error. We test the sigma-zed (SGZ) coordinate which combines Z coordinate and SIG coordinate as a replacement for the SIG coordinate to find that they effectively reduce the model’s runtime and simulation efficiency. The vertical temperature distribution in SGZ coordinate mode is more accurate than the distribution in SIG coordinate mode. The Navier-Stokes horizontal gradient and advection diffusion equation results under SIG coordinates are very sensitive to the pressure gradient. The replacement also enhances resolution near the thermocline, facilitates reclosing of the water bottom and the equal sigma surface, lends significant advantages in terms of vertical temperature in the simulation for local deep water with steep terrain, and shortens runtime for 0.14 h. SGZ mixed coordinates are recommended in the simulation of deep lakes or reservoirs wherein the underwater topography is large (with abundant continuous deep trenches or reefs).

     

Long-term study of heavy metal pollution in the northern Hangzhou Bay of China: temporal and spatial distribution,contamination evaluation,and potential ecological risk

Environmental Science and Pollution Research - Coastal ecosystem is vulnerable to heavy metal contamination. The northern Hangzhou Bay is under intensifying impact of anthropogenic activities. To...