环形热岛格局演变过程的遥感分析

城市热岛效应的空间格局在一定程度上可以反映城市规划和管理的成败得失,也是城市大气污染的驱动因素之一。〖JP2〗使用2000、2003、2004、2006、2008和2010年2～3月下午成都的6次NOAA/AVHRR（National Oceanic and Atmospheric Administration/Advanced Very High Resolution Radiometer）卫星遥感数据反演亮温,采用均值 标准差法将热岛强度分为7个等级,用面积加权平均法将研究区强度分为高温、中温和低温3类。结果表明：（1）热岛空间格局呈现巨大变异,由前期的中心型演变为中期的环型,后期是热岛环的形态和高温中心的调整阶段;（2）研究区的强度为前期强,2004年迅速减弱,高温类的强度2004年比2003年减弱259℃,2004年之后的平均减弱率仅为024℃/a;（3）城市东北部和西南部高温区的温度梯度出现逆向升降趋势。由于地表温度对城市气温有重要影响,热岛形态的变化是人们从更复杂角度分析大气污染机制、设计热岛数值模型和进行城市规划的客观依据     

Performance studies of a low heat rejection engine operated on non-volatile vegetable oils with exhaust gas recirculation

During recent decades, considerable effort has been expended world-wide to reduce dependency on petroleum fuels for power generation and transportation through the search for suitable alternative fuels that are environmentally friendly. In this respect, vegetable oils are a promising alternative to diesel fuel. However, the high viscosity, poor volatility and cold flow characteristics of vegetable oils can cause some problems such as injector coking, severe engine deposits, filter gumming and piston ring sticking and thickening of lubrication from long-term use in diesel engines. These problems can be eliminated or minimised by transesterification of the vegetable oils to form monoesters. Although transesterification improves the fuel properties of vegetable oil, the viscosity and volatility of biodiesel are still worse than those of petroleum diesel fuel. The performance of a diesel engine with such biodiesel operation can be improved further with the concept of the low heat rejection (LHR) engine. In the LHR engine, combustion surfaces on the pistons, cylinder walls and valves can be coated with ceramic materials. The objective of this study was to apply the LHR engine concept for improving engine performance when either honge biodiesel, known as honge oil methyl ester (HOME), or neem biodiesel, known as neem oil methyl ester (NOME) oils was used as an alternative fuel. For this purpose, experiments were conducted on a single cylinder, four-stroke, direct injection, water-cooled compression ignition engine using diesel, HOME and NOME oils at different injection timings of 19, 23 and 27° before top dead centre (BTDC) with and without the induction of exhaust gas recirculation (EGR). The percentage of EGR was varied from 5 to 20% in steps of 5%. The results showed that specific fuel consumption and brake thermal efficiency were improved for both of the biodiesel fuels in the LHR engine. An EGR of 10% resulted in better performance with trade-off between oxides of nitrogen and hydrocarbons/carbon monoxide emissions and hence 10% EGR is taken as the best of the range from 5 to 20%. However, readings with other EGR ratios are not reported.     

Simulation and analysis of a combined cycle heat and power plant process

The regulations of process efficiency and stricter environmental policies require analysis of large-scale thermal energy systems to produce highly efficient, cost effective and low environmental impact energy. For analysis, it is beneficial to simulate an energy system. In this paper, simulation models are developed for the analysis of a combined cycle heat and power plant located in Göteborg, Sweden. With the help of simulation models, characteristics between district heating (DH) water temperature and key parameters such as overall district heat duty, electrical power and electrical efficiency has been developed. The characteristics are useful to estimate and maximize the key parameters during varying DH water temperature. According to a comparison between the full-load simulation models of 2006 and 2013 for the selected power plant, a loss of 2 MW is noticed for gas turbine and a loss of 2.18 MW of heat flow occurs for heat recovery steam generator in the year 2013. The feasibility analysis of modifying the connection between DH economizer and main DH line provides good performance indicators in a winter scenario. The conclusions in this paper are good references to plan and improve the performance of existing large-scale thermal power plants.     

On the Role of a Decentralized Control System in Adaptation to High Ambient Temperature in a Population of the Oligochaete Tubifex tubifex

Russian Journal of Ecology -     

基于COD通量的钱塘江流域水污染生态补偿量化研究

水污染生态补偿是解决流域跨界水污染纠纷的重要措施。以行政单元为补偿主体,通过交界断面水质目标确立上下游政府间的水污染生态补偿责任,建立基于污染物通量的生态补偿量化计算方法,并提出了生态补偿运作模式。以钱塘江流域为例,根据2004年钱塘江流域水质状况,在75%保证率的水文条件下,基于COD通量估算了流域内各县（市）间水污染生态补偿量。结果表明,生态补偿量反映区域污染特点,上游地区基本上都是接受补偿者,而呈结构性污染的地区是生态补偿支付者,部分区域补偿强度超过当地经济发展水平,表明其发展不具有可持续性。钱塘江流域水污染生态补偿模式可以是政府层面上的财政支助,也可以通过项目支持、技术支持等形式实现区域间的补偿。通过生态补偿机制的实施,将对流域水环境保护起到积极的激励作用。     

间接复叠空气源热泵在铁路高寒地区建筑供暖中最优中间温度研究

针对单级空气源热泵高寒地区运行能效和供水温度低,以及直接复叠空气源热泵除霜困难的问题,对通过低环境温度空气源热泵机组与水源热泵间接复叠的系统供暖型式进行了阐述,对影响室外空气源热泵机组与室内水源热泵机组的因素进行了分析,指出环境温度依然是影响系统能效的首要因素,同时,为实现间接复叠热泵系统的能效最大,对最优中间耦合温度进行了计算。对某地区铁路工区的运行结果进行了分析,结果表明,最优中间耦合温度随环境温度的降低而降低;以最优中间耦合温度控制下的间接复叠热泵系统可以应用于我国高寒地区。     

β环糊精改性聚氨酯基涂料的火安全性与热解动力学分析

为提高膨胀型防火涂料的阻燃性能,以聚氨酯树脂为基料,以聚磷酸铵、尿素为阻燃体系,通过加入不同掺量的钛酸酯偶联剂改性β-环糊精(β-CD),提高阻燃效果。通过红外光谱仪(FT-IR)、锥形量热仪(CONE)、热重分析仪(TG)、差热扫描量热仪(DSC)等,研究改性β-CD的含量对膨胀型防火涂料的火安全性的影响,使用Coats-Redfern积分法计算涂料的热解动力学。研究结果表明：改性β-CD能有效地提高涂料的阻燃性能,当β-CD为1wt%时拥有最佳阻燃性能,1wt%改性β-CD能够提高涂层的蓄热能力,延缓APP的分解和抑制碳质材料的分解,进而提高涂料的阻燃性能。通过热解动力学拟合曲线得出,1wt%的样品能在253℃以后显著提高反应的活化能,提高涂层的阻燃性。     

论性能化防火分析中的典型火灾场景方法

火灾场景的设计是性能化防火分析的基础环节。针对可燃物众多、分布不均匀且摆放形式常有变动的大空间建筑,可以使用典型火灾场景的设计方法。在总体阐述的基础上,结合某购物广场火灾场景设定的算例对该方法的原则和步骤进行分析。可以看出,根据火灾荷栽的计算和火灾蔓延可能性的讨论,得到火灾发展的变化情况和热释放速率曲线,能够为之后的工作做好前期准备,同时显著提高这项工作的效率。     

浅谈电气火灾的原因及防范措施

本文从短路、过负载和接地故障三个方面详细地分析了电气火灾的原因，并结合有关规范提出了相应的防范措施。     

表面活性剂对细水雾雾流密度影响的实验研究

为探讨表面活性剂对细水雾雾流密度的影响,以十二烷基硫酸钠、十二烷基苯磺酸钠为研究对象,采用量杯法测量细水雾雾流密度值,分析表面活性剂对细水雾雾流密度影响,研究不同工作压力下含表面活性剂细水雾雾流密度变化规律。研究表明:表面活性剂作用下,溶液表面张力系数降低,表面能耗降低,雾场中心雾流密度减小,细水雾扩散性能得到有效改善,雾滴分布更均匀。工作压力对普通细水雾雾流密度有明显影响,工作压力越大,雾场中心区雾流密度越小,喷雾半径越大;对含表面活性剂细水雾雾流密度影响较小,中心区雾流密度变化较小。