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Transportation has dominated global fuel consumption and greenhouse gas emissions have risen in an alarming rate. Gasoline and diesel consumption for road transport have a faster growing rate than other sector and the trend appeared to be rapidly moving upwards in the near future. This has caused much concern in many countries including Malaysia to improve the sustainable energy of this sector. The focus of this paper is to analyze the trends of energy pattern and emission of road transport in Malaysia. On top of that, the review of prospective policies such as fuel economy standards and fuel switching to natural gas as well as biodiesel are summarized in this study. The study found that there is an urgent need to adopt suitable energy policy to balance the energy demand and reduce emission in this sector. This study serves as a guideline for further investigation and research in order to implement and improve the transportation sector. 相似文献
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《Energy Policy》2014
The modified Renewable Fuel Standard (RFS2) prescribes a volume of biofuels to be used in the United States transportation sector each year through 2022. As the dominant component of the transportation sector, we consider the feasibility of the light-duty vehicle (LDV) parc to provide enough demand for biofuels to satisfy RFS2. Sensitivity studies show that the fuel price differential between gasoline and ethanol blendstocks, such as E85, is the principal factor in LDV biofuel consumption. The numbers of flex fuel vehicles and biofuel refueling stations will grow given a favorable price differential. However, unless the feedstock price differential becomes extreme (biomass prices below $100 per dry ton and oil prices above $215 per barrel), which deviates from historical price trends, LDV parc biofuel consumption will fall short of the RFS2 mandate without an enforcement mechanism. Additionally, such commodity prices might increase biofuel consumption in the short-term, but discourage use of biofuels in the long-term as other technologies that do not rely on any gasoline blendstock may be preferable. Finally, the RFS2 program goals of reducing fossil fuel consumption and transportation greenhouse gas emissions could be achieved through other pathways, such as notable improvements in conventional vehicle efficiency. 相似文献
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New fuel economy standards require new U.S. passenger vehicles to achieve at least 34.1 miles per gallon (MPG) on average by model year 2016, up from 28.8 MPG today. In this paper, the magnitude, combinations and timings of the changes required in U.S. vehicles that are necessary in order to meet the new standards, as well as a target of doubling the fuel economy within the next two decades are explored. Scenarios of future vehicle characteristics and sales mix indicate that the 2016 mandate is aggressive, requiring significant changes starting from today. New vehicles must forgo horsepower improvements, become lighter, and a greater number will use advanced, more fuel-efficient powertrains, such as smaller turbocharged engines, hybrid-electric drives. Achieving a factor-of-two increase in fuel economy by 2030 is also challenging, but more feasible since the auto industry will have more lead time to respond. A discussion on the feasibility of meeting the new fuel economy mandate is included, considering vehicle production planning realities and challenges in deploying new vehicle technologies into the market. 相似文献
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为了有效分析螺旋选晶器温度场梯度对其选晶效果的影响,应用ProCAST和CAFE对镍基高温单晶合金DD4在螺旋选晶器中的晶粒组织演化进行了仿真模拟。结果表明,在其选晶过程中,在激冷面产生大量晶粒生长方向随机分布的晶核,随着离激冷面距离的增加,选晶器内的晶粒组织由等轴晶转变柱状晶,最终选出一个与<001>方向一致的晶粒;从选晶器内组织演化和晶粒数量变化角度分析,中间温度梯度的选晶效果均优于其他两种温度梯度。 相似文献
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Seong-Moon Seo In-Soo Kim Je-Hyun Lee Chang-Yong Jo Hirofumi Miyahara Keisaku Ogi 《Metals and Materials International》2009,15(3):391-398
The solidification grain structure and texture evolutions during single crystal (SX) casting of the advanced Ni-base superalloy
CMSX-4 have been investigated. In order to understand the development of the solidification grain structure, SX casting experiments
were carried out with a specially designed grain selector in a Bridgman directional solidification (DS) furnace. In addition
to casting trials, the SX casting process was simulated by a 3-D cellular automaton-finite element (CAFE) model. The predicted
solidification grain structure and the texture evolutions were validated by comparison with the microstructural observation
and the electron back scattered diffraction (EBSD) results. It was shown that the overall grain structure, crystallographic
texture evolution, and the location where the final selection of the single crystal occurs can be predicted well by the present
CAFE model. The axial texture evolution of the single crystal was found to be significantly influenced by the grain density
at the chill surface. The CAFE predictions also revealed that the geometry of the grain selector plays a significant role
in the final selection of the single crystal. 相似文献
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Yan-peng Wei Bo Yu Quan-zhan Yang Peng Gao Jian Shi Zhi-quan Miao Jing-chang Cheng Xun Sun 《中国铸造》2020,(1):21-28
Nickel-based superalloy lattice sandwich structures present higher stiffness,higher strength and higher temperature resistance in comparison with other metals.In this study,the Kagome unit was adopted to design the lattice sandwich structure and ProCAST software was used to simulate the filling and solidification processes of the nickel-based superalloy.Grain morphology and sizes of the nickel-based superalloy lattice sandwich structures were simulated by using of cellular automaton coupled with finite element model(CAFE),and indirect additive manufacture combining with investment casting were carried out to fabricate the nickel-based superalloy lattice sandwich structures.The calculated grain morphology and sizes are in good agreement with the experimental results.The grains are mainly equiaxed with an average size of about 500µm.The simulated results also show that the superheat of melting and the mold preheated temperature have significant influence on the grain size of the Kagome lattice sandwich structures,lower superheat of melting and mold preheated temperatures are encouraged to obtain the fine grains while assuring the integrity of the Kagome lattice sandwich structures for industrial application. 相似文献