Antennal responses of four species of tree-killing bark beetles (Coleoptera: Scolytidae) to volatiles collected from beetles,and their host and nonhost conifers

Summary. Host selection in tree-killing bark beetles (Coleoptera: Scolytidae) is mediated by a complex of semiochemical cues. Using gas chromatographic-electroantennographic detection (GC-EAD) and GC-mass spectrometric analyses, we conducted a comparative study of the electrophysiological responses of four species of tree-killing bark beetles, the Douglas-fir beetle, Dendroctonus pseudotsugae, Hopkins, the mountain pine beetle, D. ponderosae Hopkins, the spruce beetle, D. rufipennis Kirby, and the western balsam bark beetle, Dryocoetes confusus Swaine, to volatiles captured by aeration of 1) bole and foliage of four sympatric species of conifers, Douglas-fir, Pseudotsuga menziesii (Mirb.) Franco, lodgepole pine, Pinus contorta var. latifolia Engelm., interior spruce, Picea engelmannii x glauca, and interior fir, Abies lasiocarpa x bifolia, and 2) con- and heterospecific beetles at three stages of attack. We identified 13 monoterpenes in the conifers and nine compounds in the volatiles of beetles that elicited antennal responses. There was no qualitative difference in the terpene constitution of the four species of conifers and very little difference across beetle species in their antennal response to compounds from conifers or beetles. The lack of species-specific major or minor components in conifers suggests that beetles would need to detect differences in the ratios of different compounds in conifers to discriminate among them. Attraction to hosts and avoidance of nonhost conifers may be accentuated by perception of compounds emitted by con- and heterospecific beetles, respectively. The 22 compounds identified are candidate semiochemicals with potential behavioural roles in host location and discrimination.     

Decolorisation of Acid Blue 74 by ultraviolet/H<Subscript>2</Subscript>O<Subscript>2</Subscript>

The photodegradation of Acid blue 74 in aqueous solution employing a H₂O₂/ultraviolet system in a photochemical reactor was investigated. The kinetics of decolorization were studied by application of a kinetic model. The results show that the reaction of decolorization followed pseudo-first order kinetics. We demonstrate that there is an optimum H₂O₂ concentration, at which the rate of the decolorization reaction is maximum. Irradiation at 253.7 nm of the dye solution in the presence of H₂O₂ results in complete discoloration after ten minutes of treatment.     

An empirical analysis of economic strategies for controlling air pollution

In evaluating current environmental protection policy, economists often note that current regulations are more costly than necessary to meet environmental quality standards. While the a priori case is strong that current regulatory approaches are resulting in higher-than-necessary costs to attain environmental standards, there is relatively little empirical evidence to support this claim. The purpose of this paper is to supply some of the missing evidence by presenting the results of one study that assesses some of the potential savings associated with implementing economic, rather than command-and-control, regulatory approaches to abate one type of air pollution in one region of the country. Specifically, the paper examines the costs of meeting a prospective short-term standard for nitrogen dioxide under a range of alternative emissions control strategies for stationary sources of nitrogen oxide emissions in the Chicago Air Quality Control Region. The alternative strategies that are considered range from those that might result under current regulatory policy to those that economic policy approaches (such as emissions charges or marketable permits) are designed to implement. The analysis shows that the most efficient program of emissions controls may be more than an order of magnitude less costly than current regulatory strategies, and that economic approaches have additional advantages over more conventional regulatory approaches.     

一种高效测试污泥可生物降解性的实验方法研究

污泥的可生物降解性能由其有机组分的生物可及度和组分分子的复杂度共同决定。通过采用化学分级提取方法研究污泥组分的生物可及度,使用不同强度的提取溶液分离出4种化学可及度不同的提取组分,同时结合三维荧光光谱法对各组分中有机物质的复杂度进行分析。分析结果表明:组分的化学可及度与其生物可及度之间存在正相关关系;生物可及度较高,其成分有机物分子结构简单的组分SPOM(soluble particulate organic matter,SPOM)与REOM(readily extractible organic matter,REOM)在厌氧消化过程中降解率较高,分别为59.2%与46.3%的COD;而生物可及度低,组成复杂的组分SEOM(slowly extractible organic matter,SEOM)与PEOM(poorly extractible organic matter,PEOM)的生物降解率分别只有18.4%和5.8%的COD。     

基于Delft3D模型的三峡航道环保疏浚水质数值模拟研究

以忠县皇华城河段为例,利用Delft3D数学模型对三峡航道环保疏的水质变化进行了数值模拟。结果表明:疏浚工程的进行对河道水质环境影响比较明显,随水流方向污染物质量浓度上升速率变慢,在疏浚点污染物质量浓度上升245 mg/L,疏浚点下方4 km处污染物质量浓度上升约为20 mg/L,河段末端污染物质量浓度上升约为14 mg/L;疏浚工程结束后,河段的水体水质能够较快得到恢复,离疏浚点越近恢复得越快,疏浚结束1 d后污染物质量浓度基本已恢复到本底值,疏浚工程对水环境的影响可以较快得到恢复。     

羟基镧改性树脂的制备及其对氟离子的吸附

采用共沉淀法制备了羟基镧改性D101树脂复合吸附剂,利用扫描电子显微镜及能谱分析仪、红外光谱和比表面积分析仪对复合吸附剂的结构和形貌进行了分析,并对水溶液中氟离子(F~-)进行吸附研究,探讨了该复合吸附剂对F~-的吸附特性,并将其应用于实际含氟废水的处理。结果表明:在25℃、F~-初始质量浓度为10 mg/L、吸附剂量为0.4 g/L、溶液pH=5时,F~-吸附量最大,为24.45 mg/g;复合吸附剂对F~-的吸附动力学数据遵循拟二级动力学反应模型,整个吸附反应为多级控制过程;复合吸附剂对F~-的吸附符合Langmuir吸附等温模型,在10℃、25℃和35℃下,吉布斯自由能(ΔGo)均小于0,焓变(ΔHo)大于0,熵变(ΔSo)大于0,表明该吸附反应为自发吸热熵增过程。采用羟基镧改性D101树脂复合吸附剂可以有效去除实际含氟废水中的氟化物,实现废水的达标排放。     

Ease vs. noise: Long-run changes in the value of transport (dis)amenities

For a complete cost-benefit analysis of durable infrastructures, it is important to understand how the value of non-market goods such as transit time and environmental quality changes as incomes rise in the long-run. We use difference-in-differences and spatial differencing to estimate the land price capitalization effects of metro rail in Berlin, Germany today and a century ago. Over this period, the negative implicit hedonic price of rail noise tripled. Our results imply income elasticities of the value of noise reduction and transport access of 2.2 and 1.4, substantially exceeding cross-sectional contingent valuation estimates.     

Positive framing does not solve the tragedy of the commons

We investigate whether positive framing increases cooperation in three social dilemmas with slightly different properties: a linear public goods (PG) game, a non-linear PG game, and a common pool resource (CPR) game. Results from our laboratory experiments show that contributions to a linear PG are higher if the externality is framed positively, rather than negatively, corroborating earlier findings by Andreoni (1995). By contrast, we find no such framing effects in the non-linear PG game or the CPR game. In these games, the best response in the material payoffs is to contribute less if others contribute more, counteracting effects of pro-social preferences. Positive framing therefore does not help to solve the tragedy of the commons.     

混合基质3D打印可见光催化系统对病毒气溶胶的去除

利用3D打印灵活可控的特点和复合材料混合打印的优势，将可见光响应的ZnO/g-C₃N₄催化剂掺入ABS塑料，利用3D打印制成催化剂均匀稳定分布的光催化系统，使用流体动力学仿真模拟对反应器结构进行优化设计，用于处理相对密闭的室内空间中的病毒气溶胶.结果表明，病毒气溶胶比细菌气溶胶具有更强的抗逆性，添加螺旋导流板可以显著提升反应器传质性能并有效改善系统光催化效果，以提高对病毒气溶胶的去除率.以商业LED灯为光源的螺旋式反应器对高浓度病毒气溶胶（MS2、PhiX174噬菌体）和细菌气溶胶（大肠杆菌）具有高效去除效果，在3.75min停留时间可以实现对气溶胶的完全去除.     

火灾引发超高层建筑非连续倒塌模拟研究

为了解超高层建筑发生火灾后变形特征及失稳后的非连续坍塌过程,掌握引起变形和坍塌的原因,将三维颗粒流软件(PFC3D)作为模拟平台,设置核心筒-框架结构的超高层建筑火灾区域,并模拟坍塌过程。在考虑钢筋和混凝土共同作用结果的基础上,提出火灾区域中构件属性设置方法及模拟步骤。分析得到造成建筑结构摆动的3种原因,一是火区位置不同导致上部结构对火区的压力不同,二是火区位置不同导致结构受到的约束不同,三是受热膨胀性使构件产生不同程度变形。结果表明:燃烧温度为500℃,3 h后建筑发生摆动,表现出对火区位置和燃烧时间敏感的特征。1 000℃下1 h内,建筑物首先发生破坏的是梁构件,然后是承重柱。即建筑一旦进入结构破坏阶段,坍塌将是迅速且不可逆的。