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排序方式: 共有150条查询结果,搜索用时 31 毫秒
71.
This paper examines the possible placement of Energy Storage Systems (ESS) on an urban tram system for the purpose of exploring potential increases in operating efficiency through the examination of different locations for battery energy storage. Further, the paper suggests the utilisation of Electric Vehicle (EV) batteries at existing Park and Ride (P&R) sites as a means of achieving additional energy storage at these locations. The study achieves this through MATLAB modelling utilising captured GPS data and publically available information. This study examines the scenario of uni-directional substations with no interconnection between the overhead catenary for both directions of travel, and discusses the trade-offs between ESS size and required current limits.The results show the savings in both energy and basic CO2 emissions alongside the discussion of Return on Investment (RoI) that can be achieved through the potential installation of ESS at identified ideal locations along the tram network. Moreover, this may be extended to the use of EVs as stationary ESS sited at the existing P&R facilities. Further, the model may also be used to inform future infrastructure upgrades and potential improvements to air quality within urban environments. 相似文献
72.
This paper provides an assessment of the lifecycle Greenhouse Gas (GHG) emissions associated with the four most common sleeper (railroad tie or cross-tie in North America) types present in the UK rail network. It estimates the embodied material, process and transport emissions linked with the lifecycle activities of construction, relay/renewal and end-of-life of these variants at low and high traffic tonnage. The analysis suggests that at low traffic loads, the softwood sleepers perform the best over the whole simulated-period. At high traffic loads, the concrete sleepers outperform all other variants in terms of lifecycle CO2e emissions, followed by hardwood, softwood and steel. Regardless of the scenario examined, the steel sleepers perform the worst due to the carbon intensive nature of their manufacturing process. This performance gap is amplified at high traffic loads, as their service life is excessively compromised. The analysis reveals that the end-of-life pathway of timber is a critical determinant of its footprint. Results suggest that the impact of disposing of these sleepers results in their footprint being magnified. Nevertheless, if a minimum of 50% follows the combustion pathway with subsequent heat recuperation, then a GHG reduction potential of between 11% and 18% of their footprint is feasible. From a whole-lifecycle cost lens, for higher tonnage routes, the choice of concrete sleepers results in considerable financial savings. If the infrastructure manager was to install sleepers with stiff under sleeper pads (USPs), it may achieve additional economic and GHG savings, with potential for increasing the latter using recycled carbon-neutral USPs. 相似文献
73.
赵鄂桂 《武汉船舶职业技术学院学报》2012,11(3):77-79,86
本文对某铣工实训室楼板的荷载进行了分析,并对目前混凝土结构加固工程常见的方法进行了介绍,分析了不同方法的特点,确定了用CFRP材料加固混凝土楼板的方案。 相似文献
74.
通过斜Y铁研抗裂性试验、拉伸、弯曲、低温冲击、硬度等试验方法对DILLLMA X690T(即D690T)新型高强度结构钢焊接接头的抗裂性和力学性能进行了研究.结果表明:D690T高强度结构钢有一定冷裂倾向,但在预热温度≥100℃时,选取适合的焊接材料,可避免裂纹的产生;D690T高强度结构钢的同种接头及分别与HG785E高强钢、Q345E低合金钢焊接的异种接头均具有良好的拉仲、弯曲性能和低温冲击性能;焊接热影响区的硬度偏高,在实际生产时可适当提高预热温度. 相似文献
75.
甲醇作为重要的车用替代燃料之一,也需要测量和计算燃料消耗量。我国已发布非醇类燃料《乘用车燃料消耗量限值》标准,试验采用甲醇汽车通过底盘测功机检测C0,CO2,HC排放量,根据碳平衡法原理得出甲醇燃料消耗量数学模型。计算燃料消耗量以及甲醇与汽油当量的体积比,并通过体积比直接将排放检测报告中的数据转化成甲醇燃料消耗量。实现了燃料经济性的定量评价。 相似文献
76.
Zia Wadud 《Transportation Research Part A: Policy and Practice》2011,45(10):1052-1065
Personal road transport sector poses a significant challenge in reducing carbon emissions. This paper evaluates a policy approach known as personal tradable carbon permits to reduce carbon emissions from personal vehicles. The policy is a downstream tradable permit where individuals are allocated carbon emission caps. The policy is qualitatively evaluated in the context of carbon taxes and some upstream tradable permit options. The biggest disadvantage of such a policy is the initial set up costs. Personal tradable permits, however, are more effective than carbon taxes and are also capable of stabilizing the gasoline prices faced by the consumers when the underlying oil prices fluctuate. Since equity effects are often a concern to policy makers, the effect of such personal carbon permits on the distribution of burden is quantified in a partial equilibrium framework for the US population. Different permit allocation strategies are investigated in this regard. Using US consumer expenditure survey data, and incorporating a differentiated price response for different households, we find that all three allocation strategies considered are progressive: a per adult based allocation is the most progressive, a per vehicle allocation nearer to proportional, and a per capita allocation in between the two. Personal tradable permits therefore take care of equity concerns directly through the design of the policy. 相似文献
77.
Sgouris Sgouridis 《Transportation Research Part A: Policy and Practice》2011,45(10):1077-1091
With increasing demand for air transportation worldwide and decreasing marginal fuel efficiency improvements, the contribution of aviation to climate change relative to other sectors is projected to increase in the future. As a result, growing public and political pressures are likely to further target air transportation to reduce its greenhouse gas emissions. The key challenges faced by policy makers and air transportation industry stakeholders is to reduce aviation greenhouse gas emissions while sustaining mobility for passengers and time-sensitive cargo as well as meeting future demand for air transportation in developing and emerging countries. This paper examines five generic policies for reducing the emissions of commercial aviation; (1) technological efficiency improvements, (2) operational efficiency improvements, (3) use of alternative fuels, (4) demand shift and (5) carbon pricing (i.e. market-based incentives). In order to evaluate the impacts of these policies on total emissions, air transport mobility, airfares and airline profitability, a system dynamics modeling approach was used. The Global Aviation Industry Dynamics (GAID) model captures the systemic interactions and the delayed feedbacks in the air transportation system and allows scenarios testing through simulations. For this analysis, a set of 34 scenarios with various levels of aggressiveness along the five generic policies were simulated and tested. It was found that no single policy can maintain emissions levels steady while increasing projected demand for air transportation. Simulation results suggest that a combination of the proposed policies does produce results that are close to a “weak” sustainability definition of increasing supply to meet new demand needs while maintaining constant or increasing slightly emissions levels. A combination of policies that includes aggressive levels of technological and operations efficiency improvements, use of biofuels along with moderate levels of carbon pricing and short-haul demand shifts efforts achieves a 140% increase in capacity in 2024 over 2004 while only increasing emissions by 20% over 2004. In addition, airline profitability is moderately impacted (10% reduction) compared to other scenarios where profitability is reduced by over 50% which pose a threat to necessary investments and the implementation of mitigating measures to reduce CO2 emissions. This study has shown that an approach based on a portfolio of mitigating measures and policies spanning across technology and operational improvements, use of biofuels, demand shift and carbon pricing is required to transition the air transportation industry close to an operating point of environmental and mobility sustainability. 相似文献
78.
79.
经表面活化处理的各向同性碳(LTIA)心脏起搏电极具有优异的电性能,这已经通过模拟实验、动物实验证明。本文报告LTIA碳心脏起搏电极的临床应用情况,并对比了LTIA碳电极与铂电极在手术中所测得的各项电性能参数,结果表明:LTIA碳电极具有起搏阈值低、感知性能好、容易定位等特性。 相似文献
80.