Welfare Implications of Community Forest Plantations in Developing Countries: The Orissa Social Forestry Project

Community forest plantations are a common intervention in developing countries. We use household and remote sensing data from Orissa, India, to estimate welfare effects of community forest plantations, in terms of the value of decreased collection times plantations afford users. A selection model, accounting for possible jointness in site location and productivity, is used to estimate collection production functions for different household labor categories in natural and community forests. Two measures of an opportunity cost of time are used to determine welfare effects of time saved due to community forests. We find access to community forests is important to marginal productivity of different labor categories, but to different degrees, highlighting the need to disaggregate household data when analyzing these interventions. We also find substantial welfare improvements from time savings for many households and villages.     

燃油加油机实际检测中存在的问题及对策探究

随着时代的发展,我国综合实力与社会经济水平的提高,带动着我国汽车行业的快速发展,大量汽车与人们日常生活的融合,极大地提高了人们的日常生活水平,并在另一方面提高了对相关燃油的需求。为了保障燃油质量,同时满足油品市场的需求,相关人员需要加强燃油加油机检测水平的提高,同时借助现代化检测技术与设备,降低检测过程中的问题出现概率,并对已出现的问题进行合理解决,对燃油质量及消费者自身经济效益进行保障,进而促进相关领域的进步与发展。论文将主要对燃油加油机实际检测中存在的问题及解决对策进行深入研究。     

管输混合及贮存对汽油和柴油质量的影响

通过汽、柴油成品的混合及贮存试验,研究了发动机燃料在管道输送及贮存过程中,不同品牌产品混合后对实物质量和贮存稳定性产生的影响。对轻质燃料油成品管输及贮存提出了建议。     

谈现代汽车的粉末涂装

根据车用粉末涂料的兴起,作者详细介绍了粉末涂料的组成、特性、主要品种和应用范围;以及在粉末涂料中颜料的选择标准和粉末涂料的制造工艺特点;并指出采用粉末涂料对环境保护的影响和趋势;使用车用粉末涂料的经济性及发展前景.     

The fossil episode

Agriculture sector output (biocarbon) is a good substitute for oil in energy production but oil cannot be used as food. This one-way substitutability is analyzed in a dynamic general equilibrium model. It features three endogenous phases: a pure fossil, a mixed fossil and biocarbon and an absorbing biocarbon fuel only phase. In the latter two, the demand for biocarbon as fuel leads to increasing food prices. Depending on how easily capital and labor can reallocate, food prices increase by between 40% and 240%. The model is also used to analyze climate consequences of biocarbon fuel polices and of the shale revolution.     

A model to forecast airport-level General Aviation demand

General Aviation (GA) demand forecast plays an important role in aviation management, planning and policy making. The objective of this paper is to develop an airport-level GA demand forecast model. The GA demand at an airport is modeled as a function of social-economic and demographic factors, the availability of supply factors, the competition from the commercial aviation, the number of based aircraft, and the presence of a flight school. Our models suggest that the relative fuel price – fuel price compared with personal income – is a significant determinant of airport level GA demand. The elasticity of itinerant and local GA demand with respect to the relative fuel price is −0.43 and −0.52, respectively. Our results are compared with those reported in other studies. Furthermore, we made projections of GA demand for the airports in the Terminal Area Forecast (TAF) using three fuel price scenarios from the Energy Information Administration. Our projections under the “business-as-usual” fuel price scenario are close to those in the TAF. Our models could prove useful, for example, for the Federal Aviation Administration and airport planners to prepare airport-level GA demand forecast.     

Airport traffic complexity and environment efficiency metrics for evaluation of ATM measures

For a given (current or planned) traffic demand, different air traffic management measures could result in different airport traffic complexity and efficiency. This paper presents the research on the relationship between airport traffic complexity and time and environmental efficiency for different air traffic control (ATC) tactics applied to the given or planned airport layout. Emphasis is placed on the evaluation of airport traffic complexity, aircraft fuel consumption, gas emissions and time efficiency for different ATC tactics and/or airport airfield layouts. For busy airports during peak hours, arrival queuing delays, taxi-in, taxi-out times and departure queuing delays increase, which induces additional unnecessary fuel consumption, gas emission and time inefficiency. In order to find a tool which could indicate potential delay generators, a measure of airport traffic complexity – called Dynamic Complexity is proposed. Experiments were performed for airports with different airfield layouts, for different traffic demands and ATC applied tactics using SIMMOD simulation model. Traffic situations were analyzed and delays were measured. The values of airport traffic complexity, fuel consumption and gas emissions were also determined. A comparative analysis of the results show: first, the proposed airport traffic complexity metric quite satisfactorily reflects the influence of traffic characteristics upon the environmental state of the system, and second, different ATM strategic and tactical measures (airport airfield infrastructure development and applied ATC tactics) could significantly reduce traffic complexity and increase time and environmental efficiency at the airport.     

商用车油箱支架疲劳寿命仿真分析

汽车油箱支架是燃油供给系统中的重要部件,承受油箱的质量载荷,其主要的损伤形式是在路面冲击载荷作用下发生的疲劳失效。基于某型车出现失效问题的油箱支架的有限元模型进行了静强度分析和疲劳寿命分析,有限元仿真结果与该件破坏结果相一致。对油箱支架结构进行设计改进,并对改进结构进行了静强度和疲劳寿命分析,满足设计要求,而且在使用过程中没有发现早期断裂现象。     

黑龙江省主要湿地生物资源的文化与社会功能探析——以扎龙国家级自然保护区为例

于2009年10月对齐齐哈尔扎龙国家级自然保护区进行实地考察,从扎龙湿地生物资源结构组成入手,集中分析具有北方特点的黑龙江湿地生物资源,研究这些生物资源的社会经济文化作用,探讨其和谐现代社会的功能。