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941.
This paper presents a review of the characterization of physical properties, morphology, and nanostructure of particulate emissions from internal combustion engines. Because of their convenience and readiness of measurement, various on-line commercial instruments have been used to measure the mass, number, and size distribution of nano-particles from different engines. However, these on-line commercial instruments have inherent limitations in detailed analysis of chemical and physical properties, morphology, and nanostructure of engine soot agglomerates, information that is necessary to understand the soot formation process in engine combustion, soot particle behavior in after-treatment systems, and health impacts of the nano-particles. For these reasons, several measurement techniques used in the carbon research field, i.e., highresolution transmission electron microscopy (HRTEM), X-ray diffraction (XRD), and Raman spectroscopy, were used for analysis of engine particulate matter (PM). This review covers a brief introduction of several measurement techniques and previous results from engine nano-particle characterization studies using those techniques. 相似文献
942.
L. H. Zhao S. L. Zheng J. Z. Feng H. F. Zhou Y. F. Xing 《International Journal of Automotive Technology》2014,15(5):843-852
Accurately predicting the fatigue life is the basis for the reliability and lightweight design of automobile parts. However, the predicted lives under service loadings on the basis of the S-N curve from constant amplitude loads from existing methods often seems conservative compared with real lives, because of ignoring the strengthening effect of loads below fatigue limit. In this paper, a fatigue damage model, which is modification of Miner’s Rule, was established for the fatigue assessment under service loadings by means of taking into account the strengthening and damaging effects of loads below fatigue limit. Then this model and conventional Miner’s Rule are applied to the estimate the fatigue life of a torsion beam rear axle using the loading history recorded on proving ground. Finally, verification tests are performed on MTS road load simulator test bed. Results of predicted lives and fatigue tests demonstrate that the accuracy of the predicted life could be greatly improved by taking into account the strengthening and damaging effect of loads below fatigue limit. 相似文献
943.
Pooling, or ride-sharing, is a term coined in the United States (U.S.) to describe various forms of collective travel organised for, and often by, specific groups of commuters with similar travel requirements. Its different forms include bus pooling (financially self-supporting works bus or commuter coach services), minibus pooling (van pooling in U.S. terminology) and car pooling. It has been claimed that these forms of collective travel offer a more personalised service than conventional stage carriage buses, and therefore have a greater chance of attracting solo car drivers and increasing vehicle occupancies. This, in turn, can lead to lower fuel consumption and reduced traffic congestion at peak times. Following the advent of oil shortages in the winter of 1973/74, considerable efforts were made in the U.S. to promote pooling initiatives. This gave rise to the publication of a substantial volume of literature that sometimes indicated significant resource-saving achievements. This paper considers the potential for bus, minibus and car pooling in Great Britain, drawing both on relevant theoretical and economic studies, and on practical operational experience. It concludes that under reasonable assumptions about the transport situation in the next decade or so, pooling could become increasingly useful for solving the travel problems of individual local groups, but that it is unlikely to become a major mode in terms of the numbers of trips carried. The effects of recent legislative changes are discussed, and the justification for further change assessed. Relevant comparisons are made with the U.S.Crown Copyright 1983. Extracts from the text may be reproduced, except for commercial purposes, provided the source is acknowledged. 相似文献
944.
Cargo ship designs offered by shipbuilders differ in characteristics such as deadweight, speed, fuel consumption and cargo equipment. The best vessel for high freight markets and high fuel prices may not be the best for low freight markets and low fuel prices. A model has been developed to compare by simulation a number of multi-purpose general cargo vessels suitable for the trade of a Turkish shipowner. The model simulates the operation of each vessel under a variety of operating scenarios, e.g. fuel prices and freight profiles over the ships' lives, and estimates the distribution of resulting net present values. The techno-economic simulation model incorporates variables including ship size, speed, first cost, fuel consumption, load factor and port days.
Results are presented for six standard vessels of around 20 000 dwt operating over a long and a short route. Although the ranking of the six varies with assumptions, one design is shown to be superior under most operating conditions. 相似文献
Results are presented for six standard vessels of around 20 000 dwt operating over a long and a short route. Although the ranking of the six varies with assumptions, one design is shown to be superior under most operating conditions. 相似文献
945.
David L. Greene 《Transportation Research Part B: Methodological》1985,19(4):347-358
Understanding the potential market for limited-range vehicles is important to planning research and development programs for electric and hybrid vehicles and for gaseous-fueled vehicles as well. Studies of consumer preferences and perceptions have shown vehicle range to be a very important vehicle attribute. Studies of household vehicle use, on the other hand, have suggested that the range requirements most households place on vehicles are quite modest. The latter, however, have been severely limited by the absence of longitudinal data on the usage of individual vehicles. Instead, they have relied on single-day surveys on many vehicles, an inappropriate data source. This study develops a method for estimating daily travel distributions for individual vehicles and applies it to a recent longitudinal survey of miles and days between refuelings for over 2000 vehicles. Every vehicle in the sample has at least 30 consecutive refueling intervals. A variety of measures of “range requirement” are defined and calculated. The results confirm the existence of a substantial potential market (20–50% of all household vehicles) for vehicles with ranges on the order of 100 miles. Future research using these data and this method could describe the nature of vehicles with limited-range needs and the households which own them. 相似文献
946.
Investigation on Stability and Possible Chaotic Motions in the Controlled Wheel Suspension System 总被引:5,自引:0,他引:5
L. Palkovics P.J.Th. VENHOVENS 《Vehicle System Dynamics: International Journal of Vehicle Mechanics and Mobility》1992,21(1):269-296
The suspension system has to fulfil a large number of partly contradictory requirements which can be improved by the application of controllable elements in the wheel suspension system. A number of studies dealing with the improvement of suspension characteristics have been published. In the present paper the stability of the controlled suspension systems will be examined. In the paper the stability problems of the active suspension system is analysed and the stable parameter regions are determined. 相似文献
947.
Industrialized countries have extensive experience with various transportation energy conservation measures and have been making steady progress in improving the efficiency of their transport sector. Less Developed Countries (LDCs) have also been making progress, but their experience in many aspects of transportation energy conservation is very limited. Development organizations have funded many transportation projects in developing countries, but the vast majority of these projects were designed to improve the transportation infrastructure. Very few transportation energy conservation projects have been implemented and decision-makers face a scarcity of information on effective strategies. This paper gives an overview of transportation projects in LDCs in order to identify those transportation energy conservation measures that offer the greatest potential for LDCs. Two case studies, from Tunisia and Costa Rica, are given to illustrate the issues involved in implementing transportation energy conservation measures in LDCs. Conclusions are drawn to suggest actions for developing countries and for development organizations.Acronyms DECAT
Driver Energy Conservation Awareness Training
- DSE
Direccion Sectorial de Energia (Costa Rica)
- GDP
Gross domestic product
- km
Kilometer
- LDCs
Less Developed Countries
- TOE
Metric tonne of oil equivalent
- USAID
US Agency for International Development 相似文献
948.
D. N. L. Horton D. A. Crolla 《Vehicle System Dynamics: International Journal of Vehicle Mechanics and Mobility》1986,15(6):351-372
A theoretical analysis is presented to model a hydromechanical, semi-active suspension system, first as a single wheel station and then as fitted to each wheel of an off-road vehicle. Predicted results show that two benefits are obtained by comparison with the equivalent passive system. First, vehicle attitude is controlled for changes in body forces arising from static loads or braking/cornering inputs. Second, a significant improvement in ride comfort is obtained because low suspension stiffnesses can be used. 相似文献
949.
This paper draws from the findings of published empirical studies and observations of the impacts of rapid transit systems on urban development. Analysis is based on comparisons of impact findings by different researchers and for different cities. An initial set of key issues is proposed, against which available information is arrayed and compared. It is concluded that rapid transit can have substantial growth-focusing impacts, but only if other supporting factors are present. 相似文献
950.
INTERFERONγ-INDEPENDENTEFFECTSOFINTERLEUKIN12ADMINISTEREDDURINGACUTEOR ESTABLISHEDINFECTIONDUETOLEISHMANIAMAJORZhengShichun;W... 相似文献