Optimal policy instruments for externality-producing durable goods under present bias

When consumers exhibit present bias, the standard solution to market failures caused by externalities—Pigouvian pricing—is suboptimal. I investigate policies aimed at externalities for present-biased consumers. Optimal policy includes an instrument to correct the externality and an instrument to correct the present bias. Either instrument can be an incentive-based policy (e.g. a tax on fuel economy) or a command-and-control policy (e.g. a fuel economy mandate). Under consumer heterogeneity, a command-and-control policy may dominate an incentive-based policy. Calibrated to the US automobile market, simulation results suggest that the second-best gasoline tax is 3–30% higher than marginal external damages. The optimal price policy includes a gasoline tax set about equal to marginal external damages and a fuel economy tax that increases the price of an average non-hybrid car by about $550–$2200 relative to the price of an average hybrid car.     

Salience of carbon taxes in the gasoline market

We demonstrate that the carbon tax imposed by the Canadian province of British Columbia caused a decline in short-run gasoline demand that is significantly greater than would be expected from an equivalent increase in the market price of gasoline. That the carbon tax is more salient, or yields a larger change in demand than equivalent market price movements, is robust to a range of specifications. As a result of the large consumer response to the tax, we calculate that during its first four years, the tax reduced carbon dioxide emissions from gasoline consumption by 2.4 million tonnes.     

柴油轿车燃用煤基F-T合成油的排放特性

依据GB 18352.3-2005Ⅰ型试验循环,对帕萨特柴油轿车燃用沪四柴油、煤基F-T合成油、体积混合比例分别为10%和50%的煤基F-T合成油-沪四柴油混合燃料的CO、NOx、HC、PM和CO2排放特性进行了试验研究,分析了该车燃用F-T合成油尾气污染物排放的环境影响特性.结果表明,GB 18352.3-2005Ⅰ型试验循环中,该车燃用煤基F-T合成油-沪四柴油混合燃料城区行驶循环排放的CO、HC、PM和CO2相对较高,城郊行驶循环排放的NOx相对较高;与沪四柴油比较,该柴油轿车燃用煤基F-T合成油-沪四柴油混合燃料后,其CO、NOx、HC、PM和CO2排放均有不同程度的降低,且产生气溶胶、酸化、全球变暖等环境影响的潜力减小.煤基F-T合成油是一种较理想的柴油替代/补充燃料.     

2 ,4-二硝基苯肼固相吸附/高效液相色谱法测定车内空气中醛酮类物质

建立了2，4-二硝基苯肼固相吸附／高效液相色谱同时测定车内空气中4种醛酮类物质的方法，研究了固相吸附采样和前处理方法，优化了试验条件。4种醛酮类物质在一定质量范围内工作曲线线性良好，甲醛、乙醛、丙烯醛、丙酮的检出限分别为0．075μg／m^3、0．207μg／m^3、0．715μg／m^3、0．159μg／m^3（按采样体积12L计），实际样品测定的RSD为7.5％-9．7％。     

石脑油卸车系统控制技术的应用

介绍了采用真空辅助液压潜油泵接卸铁路槽车石脑油的卸车工艺系统在安全环保方面存在的问题，提出了安全控制措施方案及控制系统，并对控制系统的实施效果进行了分析。     

混铁车强制冷却场集尘系统改造

混铁车强制冷却场原设计为露天敞开式,有4个工作台位,在强制冷却(采用大风量风机经过特制送风头送入炉膛内,将其温度从350℃左右冷却到40℃)过程中,产生了大量扬尘,不仅污染了周围环境,还严重威胁了岗位职工的身体健康.     

人车碰撞中行人大腿保护研究

研究提高人车碰撞中行人大腿的保护性能的方法。首先对大腿伤害机理,伤害评价指标以及车辆自身结构进行阐述和研究,总结车辆前端结构的关键参数;对某车型的前大灯进行结构改进,按照欧洲新车安全评鉴协会(Euro NCAP)行人大腿保护的试验评价方法,改进后进行碰撞试验;建立装有发动机罩安全气囊的整车仿真模型,验证安全气囊对行人大腿的保护性能。经过试验和仿真可以得出:车辆前大灯结构刚度改进和发动机罩安全气囊可以改善行人大腿的保护性能。     

Three-dimensional visualization and quantification of non-aqueous phase liquid volumes in natural porous media using a medical X-ray Computed Tomography scanner

This study demonstrates the capabilities of a typical medical X-ray Computed Tomography (CT) scanner to non-destructively quantify non-aqueous phase liquid (NAPL) volumes, saturation levels, and three-dimensional spatial distributions in packed soil columns. Columns packed with homogeneous sand, heterogeneous sand, or natural soil, were saturated with water and injected with known quantities of gasoline or tetrachloroethene and scanned. A methodology based on image subtraction was implemented for computing soil porosity and NAPL volumes in each 0.35 mm x 0.35 mm x 1 mm voxel of the columns. Elimination of sample positioning errors and instrument drift artifacts was essential for obtaining reliable estimates of above parameters. The CT data-derived total NAPL volume was in agreement with the measured NAPL volumes injected into the columns. CT data-derived NAPL volume is subject to a 2.6% error for PCE and a 15.5% error for gasoline, at average NAPL saturations as low as 5%, and is mainly due to instrument noise. Non-uniform distributions of NAPL due to preferential flow, and accumulation of NAPL above finer-grained layers could be observed from the data on 3-D distributions of NAPL volume fractions.     

流域开发项目环评的深层思考

通过对一西部流域梯级开发水电站环评及其显现的环境问题案例,产生对流域梯级开发项目进行分割式单项环评存在问题的思考,提出对梯级开发环境影响评价必须贯穿流域规划,建立累积环境影响的基本概念和理论,并从其管理机制及公众参与机制上保证流域开发环评的有效实施,使环评在流域梯级开发中真正发挥对生态环境调控的作用.     

Can new passenger cars reduce pedestrian lower extremity injury? A review of geometrical changes of front-end design before and after regulatory efforts

Objective: Pedestrian lower extremity represents the most frequently injured body region in car-to-pedestrian accidents. The European Directive concerning pedestrian safety was established in 2003 for evaluating pedestrian protection performance of car models. However, design changes have not been quantified since then. The goal of this study was to investigate front-end profiles of representative passenger car models and the potential influence on pedestrian lower extremity injury risk.

Methods: The front-end styling of sedans and sport utility vehicles (SUV) released from 2008 to 2011 was characterized by the geometrical parameters related to pedestrian safety and compared to representative car models before 2003. The influence of geometrical design change on the resultant risk of injury to pedestrian lower extremity—that is, knee ligament rupture and long bone fracture—was estimated by a previously developed assessment tool assuming identical structural stiffness. Based on response surface generated from simulation results of a human body model (HBM), the tool provided kinematic and kinetic responses of pedestrian lower extremity resulted from a given car's front-end design.

Results: Newer passenger cars exhibited a “flatter” front-end design. The median value of the sedan models provided 87.5 mm less bottom depth, and the SUV models exhibited 94.7 mm less bottom depth. In the lateral impact configuration similar to that in the regulatory test methods, these geometrical changes tend to reduce the injury risk of human knee ligament rupture by 36.6 and 39.6% based on computational approximation. The geometrical changes did not significantly influence the long bone fracture risk.

Conclusions: The present study reviewed the geometrical changes in car front-ends along with regulatory concerns regarding pedestrian safety. A preliminary quantitative benefit of the lower extremity injury reduction was estimated based on these geometrical features. Further investigation is recommended on the structural changes and inclusion of more accident scenarios.