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11.
Pedestrians and bicyclists are the victims of countless car crashes in U.S. cities as well as around the world. Yet, many
dimensions of their involvement in crashes remain rather poorly known. In this article, we follow a spatial epidemiologic
approach to study the relative risk factors of bicycle and pedestrian crashes at the neighborhood level in the City of Buffalo,
NY over a two-year period. The analysis examines physical road characteristics such as roadway and intersection functional
classes, urban density and type of development—business or residential, as well as socio-economic and demographic variables
to identify discriminating risk factors between the two non-motorized transportation modes. The analysis underscores significant
differences tied to neighborhood ethnicity, educational attainment and land use, while physical characteristics of the road
infrastructure register as marginally discriminating factors. Income related socio-economic status is not found to play a
prominent role. 相似文献
12.
This paper proposes a new equivalent failure strength model for spot welds under combined axial and shear loading. To evaluate the pure-shear strength of spot welds fabricated under the same welding conditions with a two-layered lap joint, a test fixture and a specimen were newly designed and proposed. The failure tests of spot welds of TRIP590 1.2t, DP780 1.0t, DP780 1.2t, and DP980 1.2t were carried out at seven different loading angles ranging from 0° to 90° at an internal angle of 15° to obtain the failure loads. The failure loads obtained from the experiments were utilized to construct the failure criterion and thus describe the failure behavior of spot welds in the crash analysis or strength analysis of an auto-body. It is noted that the value of β in the failure criterion for spot welds of AHSS is different from the values of conventional steels. The new equivalent failure strength model proposed in this paper was derived from the failure test results to provide a representative failure model that can be used to accurately compare the failure characteristics of different materials under the same conditions. 相似文献
13.
Sung Jun Ha Ung Chun Jong Yun Park Moon Sang Kim 《International Journal of Automotive Technology》2017,18(5):779-784
High pressure acting on the vehicle’s body plays an important role in deciding the aerodynamic drag. An idea has been suggested to enhance the aerodynamic performance for small passenger car by relieving the high pressure in the engine room. The high pressure inside the engine room can be released to the outside of the vehicle through a hole perforated on the wheel house liner. About 1 % of the drag coefficient can be improved with the 1.88 % of the radiator air mass flow rate increment by installing the top hole with slots on the wheel house liner. Flow simulations are performed at the driving velocity of 110 km/h with the moving wall condition of the same velocity. The tire is rotating to catch more precise flow physics around a tire and wheelhouse liner. 相似文献
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15.
Chang Doo Jang Tae Hoon Kim Dae Eun Ko Thomas Lamb Yun Sok Ha 《Journal of Marine Science and Technology》2005,10(4):211-216
In a shipyard, line heating and triangle heating are two major processes carried out by skilled workers to form curved plates
in various shapes under various heating conditions. There have been many studies on line heating, but triangle heating has
rarely been studied owing to its complicated heating process with irregular multiheating paths and highly concentrated heat
input. Triangle heating is the most labor-intensive job. Hence, it is essential for most shipyards to study the automation,
as well as the improvement, of the triangle heating process in order to increase hull-forming productivity. In this study,
a pioneering attempt to simulate triangle heating was made. A circular disk-spring model is proposed as an analysis model
for the elastoplastic procedure of triangle heating, and the inherent strain method is also used to analyze the deformation
of plates. The results of the simulation were compared with those of experiments and showed good agreement. It is shown that
the present approach and the model used in this study are effective and efficient for simulating triangle heating for the
steel plate forming process in shipbuilding. 相似文献
16.
冷却液是保证水冷式发动机正常工作必不可少的重要介质,若发动机过热或过冷,就会导致发动机功率下降、加剧运动件的磨损及燃料消耗增加等。介绍了电喷式发动机对冷却液的要求、电喷发动机常年使用冷却液的优点及其使用注意事项。 相似文献
17.
现在生意场上有一种比较流行的合作方式,叫做连锁或者加盟,说的白一点就是挂靠.也许这一说法有点刺耳,生意场上的人很忌讳用这一词,而改用连锁、加盟,这在服务性行业尤为普遍.货代企业也沿用这种做法,俗称挂靠. 相似文献
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M. H. Lee H. M. Lee K. S. Lee S. K. Ha J. I. Bae J. H. Park H. G. Park H. J. Choi H. H. Chun 《International Journal of Automotive Technology》2011,12(5):733-744
In this paper, a hardware-in-the-loop simulation (HILS) system was developed before the development of an electric power steering
(EPS) system in a vehicle. This study was focused on the establishment of the HILS system. Driving conditions are simulated
with the HILS system. The actual steering input parameters are confirmed on the monitor while driving the HILS system. The
steering forces observed in the simulation with the developed HILS system are similar to those in real vehicle tests. The
developed HILS system can be applied in the development of various types of EPS systems. 相似文献
20.
We investigated the effects of the fuel injection timing — both for early and late injection — in conjunction with the throttle
opening ratio on the fuel-air mixing characteristics, engine power, combustion stability and emission characteristics of a
DI CNG spark engine and control system that had been modified and designed according to the author’s original idea. We verified
that the combustion characteristics were affected by the fuel injection timing and that the engine conditions were affected
by the throttle opening ratios and the rpm. The combustion characteristics were greatly improved for a complete open throttle
ratio with an early injection timing and for a partial throttle ratio with a late injection timing. The combustion duration
was governed by the duration of flame propagation in late injection timing scenarios and by the duration of early flame development
in cases of early injection timing. As the result, the combustion duration is shortened, the lean limit is improved, the air-fuel
mixing conditions are controlled, and the emissions are reduced through control of the fuel injection timing and vary according
to ratio of the throttle opening. 相似文献