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931.
In order to improve the economical and environmental performances of the Diesel engines, the present paper aims to bring to the forefront solutions to increase the efficiency of the supercharging process carried out by the aggregates with Comprex type pressure waves. One solution to this is to drive the Comprex, not by the supercharged engine as it currently happens, but by a DC motor. The speed of the electric motor is modified, by means of an electronic management system, depending on the speed and load of the Diesel engine. The paper presents the experimental results obtained during the investigation of a supercharged Diesel engine by the Comprex driven type according to the proposed solution. 相似文献
932.
从美国校车发展历程、校车管理以及校车安全标准3个方面概述美国校车。一旦发生紧急情况,紧急逃生对于保障学生安全举足轻重,而国内相关研究相对薄弱。从常见紧急情况、紧急逃生原则、紧急逃生演练等不同视角详细阐述美国校车事故的紧急逃生,对于改善中国校车安全现状具有积极意义。 相似文献
933.
934.
P. Weston G. Yeo E. Stewart 《Vehicle System Dynamics: International Journal of Vehicle Mechanics and Mobility》2015,53(7):1063-1091
This paper presents a view of the current state of monitoring track geometry condition from in-service vehicles. It considers technology used to provide condition monitoring; some issues of processing and the determination of location; how things have evolved over the past decade; and what is being, or could/should be done in future research. Monitoring railway track geometry from an in-service vehicle is an attractive proposition that has become a reality in the past decade. However, this is only the beginning. Seeing the same track over and over again provides an opportunity for observing track geometry degradation that can potentially be used to inform maintenance decisions. Furthermore, it is possible to extend the use of track condition information to identify if maintenance is effective, and to monitor the degradation of individual faults such as dipped joints. There are full unattended track geometry measurement systems running on in-service vehicles in the UK and elsewhere around the world, feeding their geometry measurements into large databases. These data can be retrieved, but little is currently done with the data other than the generation of reports of track geometry that exceeds predefined thresholds. There are examples of simpler systems that measure some track geometry parameters more or less directly and accurately, but forego parameters such as gauge. Additionally, there are experimental systems that use mathematics and models to infer track geometry using data from sensors placed on an in-service vehicle. Finally, there are systems that do not claim to measure track geometry, but monitor some other quantity such as ride quality or bogie acceleration to infer poor track geometry without explicitly measuring it. 相似文献
935.
On November 30, 2006, USS Boone (FFG 28) lost all steering control in the Mediterranean Sea due to a lost rudder. Within hours of the casualty, numerous US Navy and contractor activities sprung into action to coordinate and complete an emergent voyage repair to return USS Boone to service to support the Global War on Terrorism. The Navy faced a large hurdle to identify and transport a replacement rudder to Rota, Spain, and prepare and carry out an extremely complex repair procedure. Pearl Harbor Naval Shipyard personnel removed the replacement rudder from USS Crommelin (FFG 37) in Pearl Harbor Naval Shipyard and transported the rudder to Rota, Spain. The Navy's Supervisor of Salvage and Diving developed the repair procedure and coordinated the repair operation, which involved over 30 US Navy and contractor divers. The repair team completed the rudder replacement on December 28, 2006 and returned USS Boone to underway operations. 相似文献
936.
937.
Error quantification of a high-resolution coupled hydrodynamic-ecosystem coastal-ocean model: Part 2. Chlorophyll-a, nutrients and SPM 总被引:1,自引:0,他引:1
J. Icarus Allen Jason T. Holt Jerry Blackford Roger Proctor 《Journal of Marine Systems》2007,68(3-4):381-404
Marine systems models are becoming increasingly complex and sophisticated, but far too little attention has been paid to model errors and the extent to which model outputs actually relate to ecosystem processes. Here we describe the application of summary error statistics to a complex 3D model (POLCOMS-ERSEM) run for the period 1988–1989 in the southern North Sea utilising information from the North Sea Project, which collected a wealth of observational data. We demonstrate that to understand model data misfit and the mechanisms creating errors, we need to use a hierarchy of techniques, including simple correlations, model bias, model efficiency, binary discriminator analysis and the distribution of model errors to assess model errors spatially and temporally. We also demonstrate that a linear cost function is an inappropriate measure of misfit. This analysis indicates that the model has some skill for all variables analysed. A summary plot of model performance indicates that model performance deteriorates as we move through the ecosystem from the physics, to the nutrients and plankton. 相似文献
938.
外观最大的改变.来自于车头造型。乍看之下.或许会觉得似曾相识.没错.因为在Ford强调承袭家族风格的手法下.08款的Escape在车头的设计元素.更为接近Explorer与Expedition两位老大哥.而主导计划的首席设计师DoyleLetson也表示让Escape比以往更加强悍。 相似文献
939.
940.
V. Pracny M. Meywerk A. Lion 《Vehicle System Dynamics: International Journal of Vehicle Mechanics and Mobility》2007,45(1):1-14
The method of numerical multi-body simulation is an often used and well-understood development tool in the automotive industry. In order to reproduce the ride comfort or handling behaviour of vehicles, mathematical models have to be built up. To achieve accurate simulation results, highly detailed component models are required. However, the formulation of appropriate physically-based model equations of complex automotive components (e.g. air springs, shock absorbers, rubber bearings, tyres, etc.) can be very difficult. To handle this, empirical modelling methods have been developed. Simple algebraic equations are used to describe complex system behaviour. This simplification is very effective, although it largely ignores the natural laws of mechanics and thermodynamics but is still capable to predict the component response. This article illustrates how to take advantage of this approach in numerical simulations. We describe the development of a hybrid automotive shock absorber model based on both spline and neural network (NN) approaches. By combining these different approaches, an accurate model is achieved without loss of variability. Non-isothermal laboratory force-displacement measurements of an automotive shock absorber are being used to estimate the parameters of the NN. As shown, the model replicates the measured data with sufficient accuracy, especially the hysteresis. Finally, we present a set of quarter-car simulations with a built-in hybrid NN shock absorber. 相似文献