Use of hybrid vehicles in Japan: An analysis of used car market data

Despite the rapid market penetration of hybrid vehicles (HVs), their usage and contributions to environmental protection have not been examined by vehicle traveling data. In this paper, we analyzed Japan’s used car market data to understand how HVs are used on the street. We find GV drivers with high travel demand switched from GVs to HVs during the transition period. Despite HV owners driving much longer distances than conventional gasoline vehicle (GV) owners, they emit less carbon dioxide (CO₂) emissions, owing to better fuel economy. We also find that HV owners spend roughly the same amount of money annually as GV owners. However, the per-kilometer travel cost of HVs is much lower than that of GVs even if the depreciation cost of the vehicle and vehicle related taxes are included in the analysis.     

Would personal carbon trading reduce travel emissions more effectively than a carbon tax?

The application of personal carbon trading (PCT) to transport choices has recently been considered in the literature as a means of reducing CO₂ emissions. Its potential effectiveness in changing car travel behavior is compared to the conventional carbon tax (CT) by means of a stated preferences survey conducted among French drivers (N ∼ 300). We show evidence that PCT could effectively change travel behavior and hence reduce transport emissions from personal travel. There is however a definite reluctance to reduce car travel. We were unable to demonstrate any significant difference between the effectiveness of PCT and the CT with regard to changing travel behavior. However, in the experiment, the PCT scheme provided consistent results while this was not the case for the CT scheme. Further research is needed into the “social norm” conveyed by a personal emissions allowance.     

Real-world gaseous and particle emissions of a Bi-fuel gasoline/CNG Euro 6 passenger car

The objective of the present study is the assessment of the environmental impact of a bivalent (bi-fuel) vehicle, running either on gasoline or compressed natural gas (CNG). To that aim, a Euro 6 passenger car was tested under various real-world driving conditions. In order to cover the full range of conventional powertrains currently in the market, the tests were also repeated on a Euro 6 diesel passenger car. Both cars were driven in two routes, the first complying with the regulation limits and the second going beyond them. Carbon monoxide (CO), nitrogen oxides (NO_x) and particle number (PN) emissions were recorded using a Portable Emissions Measurement System (PEMS). Apart from the aggregated emission levels, in g/km, the exact emission location along the route was also assessed. Natural gas proved beneficial for CO and PN emissions, the level of which always remained below the respective legislation limits. On the other hand, under the dynamic driving conditions with gasoline, the relevant limits were exceeded. Cold start, occurring at the beginning of the urban part, and motorway driving were identified as major contributors to total emissions, especially in gasoline mode. However, the application of natural gas was associated with a penalty in NO_x emissions, which were significantly increased as compared to gasoline. Local peaks within the urban part were identified in CNG mode. In any case, the diesel vehicle was by far the highest NO_x emitter.     

The role of ‘indirect’ greenhouse gas emissions in tourism: Assessing the hidden carbon impacts from a holiday package tour

Tourism is a noticeable contributor to global greenhouse gas (GHG) emissions. Existing estimates of tourism’s carbon footprint are however incomplete as they fail to holistically assess the additional, ‘indirect’ carbon requirements. These arise from the non-use phases of a tourism product or service life cycle and can be further magnified by supply chain industries. Under-development of methods for carbon impact assessment in tourism is the primary reason for the omission of ‘indirect’ GHG emissions. This study develops a new approach for comprehensive appraisal of GHG emissions which incorporates and advances the methodological advantages of existing assessment techniques. It tests the applicability of this approach in tourism by conducting a holistic analysis of a standard holiday package to Portugal, based on the British tourism market. The new approach demonstrates the significance of the ‘indirect’ GHG emissions in the total carbon footprint from the holiday package, thus emphasising the necessity for more comprehensive future assessments.     

Assessment of carbon emission costs for air cargo transportation

This study presents a set of models that calculate carbon emissions in individual phases of flight during air cargo transportation, investigates resultant carbon footprints by aircraft type and flight route, and estimates increases in transportation costs for airlines due to carbon taxes imposed by the EU ETS. The estimated results provide useful references for airlines in aircraft assignment on different routes and in aircraft selection for new purchases. Validation of the model is conducted by simulating the potential impact of the implementation of the EU ETS on costs of air cargo transportation for six routes and six types of aircraft. Results show that the impact may be subject to various factors including unit carbon emissions per aircraft, aviation emission allowances per airline, and carbon trading prices; and that increases in costs of air cargo transportation range from 0% to 5.27% per aircraft per route. Therefore, the implementation of the EU ETS may encourage airlines to cut down their operating costs by reducing their carbon emissions, thereby ameliorating greenhouse gas pollution caused by air cargo transportation.     

摩托车转向轴承挡碗碎裂的研究（1）

摩托车重要的齿轮、曲轴、转向轴承挡碗大部分都是用20CrMo或日本SCM420H材料，热处理工艺为渗碳、一次淬火、回火，工艺过程中如碳势、温度时间等控制不当，都会导致零件马氏体组织粗大，在不平衡力、力矩作用下或压装时零件碎裂，所以，工艺参数碳势和温度的管理是保证产品不碎裂的前提。     

Carbon and nutrient dynamics in a hypertrophic lagoon in southwestern Taiwan

Dissolved and particulate phases of carbon (DIC, DOC, POC) and nutrients (DIN, DIP, DSi, DON, DOP, PN) were investigated bimonthly from August 1999 to August 2000 to study biogeochemical dynamics of carbon and nutrients in Tapong Bay, a small semi-enclosed and hypertrophic lagoon in southwestern Taiwan. The lagoon has only a tidal inlet for exchanging water between Tapong Bay and Taiwan Strait, which may result in low water exchange rates and various oxygen-deficient conditions in bottom water of the inner bay during warm seasons. The water exchange time of Tapong Bay ranges from 7 days (summer) to 13 days (winter) with a mean of 10 days. Nutrient dynamics were largely ascribed to allochthonous inputs, biological and exported removals in the lagoon. Diffusion fluxes from sediments to overlying water accounted for only about 7.6% of annual DIN inputs and 1.0% of annual DIP inputs. High primary productivity (89 mol C m⁻² year⁻¹) supported by abundant nutrients primarily drove the lagoon into a hypertrophic condition as particulate organic matter was derived mainly from biological production. Excess of DIP appeared to occur throughout the study period in the lagoon. Temperature, solar radiation and turbidity, rather than nutrients, perhaps controlled seasonal variations of primary productivity. The net ecosystem production (NEP) derived from daily changes of DOC and POC inventories was about 6.3 mmol C m⁻² day⁻¹ that was close to 6.7 mmol C m⁻² day⁻¹ simulated from the biogeochemical modeling. Therefore, the net ecosystem production (NEP) rate of organic carbon estimated from the biogeochemical model was reliable, and the NEP was temporally variable with an annual mean of 5.8 mol C m⁻² year⁻¹, implying that Tapong Bay was an autotrophic system. Although calcification proceeded pronouncedly in warm seasons, an invasion of CO₂ was significant in this system. In terms of nitrogen budget, the annual nitrogen fixation exceeded the annual denitrification with a magnitude of 1.30 mol N m⁻² year⁻¹, which may be supported by the abundance of nitrogen fixation microplanktons in the lagoon.     

碳纤维复合材料车用结构设计与仿真研究综述

汽车轻量化技术是实现汽车节能减排的重要举措,已成为国内外汽车工业界的研究热点。碳纤维复合材料在车身上的系统应用引领了汽车行业,尤其是新能源汽车的轻量化进程。本文对国内外碳纤维复合材料车身及零部件的研究成果进行回顾与总结,从结构设计与性能仿真两个方面对目前的研究成果进行了综述,并分析存在的问题和进一步深入研究的方向。     

Increasing urban tram system efficiency,with battery storage and electric vehicle charging

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.     

A carbon footprint analysis of railway sleepers in the United Kingdom

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.