通过控制过量空气系数提高注汽锅炉热效率

通过理论分析及现场测试 ,分析了过量空气系数对注汽锅炉热效率的影响 ,得出了在注汽锅炉实际运行中应加强对过量空气系数的监控 ,使过量空气系数降低 ,从而提高注汽锅炉热效率的结论     

The impact of Low Emission Zones on particulate matter concentration and public health: A Comment

Malina and Scheffler estimated the impact of Low Emission Zones (LEZs). LEZ effects are small and bias control is of paramount importance. Based on our analyses we conclude that the point estimate of monetary health benefits calculated by Malina and Scheffler is probably too high and the uncertainty reported possibly too small.     

基于版本控制技术和生命周期理论的企业文档管理平台设计

针对当前广泛使用的文档管理系统较少以安全、效率为目标,无法实现企业文档安全管理和维持较高管理效率的问题,基于文档版本控制技术和生命周期理论,根据文档管理平台功能模块,设计适用于该类企业的文档管理平台,实现企业文档的安全有效管理。     

The efficiency of public transport operations – An evaluation using stochastic frontier analysis

The aim of this study is to evaluate the efficiency of public transport operations undertaken in Swedish counties by the Public Transport Authorities (PTA), taking into account the substantial differences in operating conditions between counties. The analysis will be performed using Stochastic Frontier Analysis (SFA) with annual data from 1986 to 2009 for 26 Swedish counties. The analysis shows how the efficiency of the individual counties has changed over time. The results are used to provide a ranking (in terms of efficiency) of the Swedish public transport authorities that can provide a basis for benchmarking. It is concluded that the efficiency of the public transport providers in all counties fell during the observed time period. Defining cost efficiency as the ratio of minimum cost to observed cost, the overall (average) cost efficiency for the industry fell from 85.7% in the eighties to 60.4% for the period from 2000 to 2009. Possible explanations for the development include increased emphasis on route density as well as higher environmental and safety requirements.     

27000 dwt多用途船能效设计指数研究与分析

随着世界贸易的快速发展,海运业对环境的污染日益显著,国际海事组织（IMO）海上环境保护委员会提出船舶能效设计指数（EEDI）用来衡量船舶设计能效水平.本文对27 000 dwt多用途船其EEDI指数进行分析研究,该船的EEDI计算过程和计算结果已经得到法国BV船级社的认可,相关研究结论可供船舶设计人员参考.     

Impact of service network topology on air transportation efficiency

Each stakeholder in the air transportation system has a different perspective on the performance efficiency metrics, making analysis of system-wide design options very difficult. This paper uses topological structures of service networks to examine trade-offs between efficiency metrics established around the passenger, airline, and air navigation service provider perspectives. The findings indicate that the scale-free type topologies are preferred under most of the metrics. However, with enough density, random topologies become more appealing with its high robustness feature and performance comparable to scale-free.     

上海地区铁路冷链物流发展对策研究

随着我国国民经济快速发展,冷链物流需求快速提升,公路冷链物流发展迅猛,但铁路冷链物流增速明显滞后于行业发展。为加快上海地区铁路冷链物流发展,阐述上海地区铁路冷链物流的发展现状,从运输时效、运输价格、能力供给、集配货模式、应急处置等方面分析铁路冷链物流发展存在的问题,提出大力组织班列开行、采用灵活价格政策、加大装备车辆供给、提供多样性物流服务、提升应急处置能力、推进行业标准出台等提升铁路冷链物流市场竞争能的对策,为实现上海地区铁路冷链货运量增长及铁路冷链物流持续健康发展提供支撑。     

Analyzing the effects of Gas-to-Liquid (GTL) diesel blending on the efficiency and emissions of petroleum refineries and transport fuels in the U.S. and Europe

The transport sector is fast changing with demand for distillates increasing amidst declining gasoline consumption in many markets especially in the developed world. Increasingly refineries are stretched to operate less efficiently and this is manifested through a drop in efficiency as a consequence of increasing diesel production via less efficient routes, particularly on the marginal barrel of diesel. It has been suggested that this decline in diesel production efficiency, as the ratio of gasoline to diesel (G/D) production drops, can partly be mitigated through the use of Gas-to-Liquid (GTL) diesel. In this paper we adopted refinery Linear-Programming models to represent the refining system in Europe as well as a district in the U.S. to investigate the effects of increased availability of GTL diesel to a refiner on the energy efficiency and GHG emissions of refineries. Here we showed that indeed there is an improvement in diesel production efficiency with increasing GTL concentrations, but this efficiency gain (<0.5%) is insufficient to counteract the higher energy consumption and emissions associated with the production of GTL, thus leading to an overall decline in life cycle efficiency (up to 5%), and an increase in life cycle GHG emissions (up to 2%).     

Future planning for benchmarking and ranking sustainable suppliers using goal programming and robust double frontiers DEA

Decision-making for selecting sustainable suppliers has become an intricate duty. To rank sustainable suppliers and select benchmarks this paper proposes an efficiency improvement plan. Two levels of improvement plans including goals and benchmarks are presented for the suppliers. To this end, the first-level goals are obtained using goal programming (GP) and data envelopment analysis (DEA). Since inputs and outputs of the first-level goals might be imprecise, robust Charnes-Cooper-Rhodes (CCR) model is run. As a result, the benchmarks of the second-level are obtained. Then, a robust CCR inefficiency model is applied for ranking the suppliers. In fact, such a ranking capability is made by creating double-frontiers including CCR efficiency and inefficiency frontiers. Accordingly, the suppliers are ranked using the first-level goals. In the new ranking, uncertainty of the goals is considered by running robust optimization technique. The proposed approach provides technical and planning capabilities which are demonstrated by a case study.     

The impact of competition on container port (in)efficiency

There are many studies on container port efficiency and that seek to understand what factors, such as technical and scale efficiency, private versus public terminal management or macro-economic factors, play on the efficiency score of a given port. There are fewer studies that focus on the role played by the inter-port competitive environment. This role remains difficult to assess. In fact, on the one hand, a port subject to high inter-port competition may record higher efficiency scores due to the pressure from the competitive environment. On the other hand, a port subject to high competition may be forced to over-invest and could therefore records a lower efficiency score. This article investigates this issue and examines how the degree of competition measured at different levels (local, regional and global level) impacts the efficiency score of a given container port. To do so, we implement a truncated regression with a parametric bootstrapping model. The model applied to information gathered for 200 container ports in 2007 and 2010 leads to the following conclusions: port efficiency decreases with competition intensity when measured in a range of 400–800 km (regional level); and the effect from competition is not significant when competition is measured at a local (less than 300 km) or at a global (more than 800 km) level. Estimates also show a tendency for ports who invested from 2007 to 2010 to experience a general decrease in efficiency scores, an element which could be explained by the time lag between the investment and the subsequent potential increase in container throughput.