重型车架螺栓扭矩的影响因素及对策

通过试验,分析并归纳了影响重型车架螺栓力矩的主要因素,包括螺栓（螺母）的装配方式、垫圈的型号、螺栓（螺母）与连接件的接触面积、被联接件表面粗糙度、螺栓孔径、层板间隙、环境、操作方法和使用工具等几个方面,同时在实际生产中采取了相应的解决措施,具有很强的实用性和参考价值。     

公路施工对路面平整度影响的因素分析

通过沥青路面施工对路面平整度可能造成影响的各环节进行的分析,提出了相应的防治措施,以保证路面平整度。     

Rural speed limit changes and safety

There is little information in the literature on the relation between rural speed and safety. The wide variation in rural speed limits that are applied in different countries tends to confirm that this relation is poorly understood. The changes in fatal, injury and all accidents that followed a change in the rural speed limit in seven countries were regressed against the change in vehicle mean speed. The results showed that speed significantly affects safety and that within certain limits the relation is linear. The regressions indicated that a 1 km/h reduction in speed will reduce all severities of accidents by between 4 and 5%. It is suggested that part of this reduction is due to a change in economic factors.     

基于环境因素和基准化原理的信息资源配置研究

针对维修信息资源特点，以装备维修系统投入、产出为双目标，兼顾决策者偏好，引入环境背景值及针对多阶段过程的时间窗，建立装备维修信息资源优化配置DEA模型，并采用基准化思想评价资源配置效率。算例分析结果符合实际，最优结果和效率评价分析为决策者提供决策支持，利于提高装备维修保障效用，充分发挥装备维修资源作用。     

农村客运运力配置的影响因素探析

农村客运运力配置不仅是农村客运规划中的重要内容，也是制定客运规划的主要因素之一，其主要包括运力规模配置和运力结构配置两个方面的内容。系统分析影响农村客运运力配置的内、外部因素，可以全面了解农村客运运力规划需考虑的各种问题，从而有助于制定更加科学、更加合理的农村客运运力发展规划，也有助于使农村客运发展的实施过程更加有序化、更加合理化。     

摩托车燃油蒸发污染物排放测试浅析（1）

要保证燃油蒸发测试的准确性，首先应确保车辆状态的稳定，包括炭罐的老化、炭罐正常的吸附、脱附，及油气管路的正确连接等。对燃油蒸发测试结果影响最大的因素是油品和试验用油的蒸气压，只有在试验用油和燃油蒸气压一致的条件下，各种测试结果才有可比性。因此，日后在进行燃油蒸发试验时应重点关注燃油的蒸气压。     

One manufacturer's approach to improving jet transport fuel efficiency

In the face of rapidly escalating costs of aircraft fuel, since the early 1970s, the aerospace industry has embarked on a program of measures to reduce fuel consumption. This article describes an integrated set of measures which have been undertaken by Lockheed‐California to improve the fuel requirements of the Tristar, a wide‐bodied three engine medium to long range aircraft. Measures include operational changes, improvements to maintenance practices, long term hardware modifications and technological advances.     

On stress concentration factors for tubular Y- and T-Joints in frame structures

This paper is written as a result of some years experience with fatigue analysis of offshore jacket structures where the connections are made as tubular joints. The hot spot stresses at the tubular joints in such analysis are normally derived based on parametric equations for stress concentration factors. These stress concentration factors are normally related to the axial force in the brace. It is observed that the hot spot stresses at the crown positions of the tubular joint in some cases are significantly affected by the local loading on the chord and the bending moment in the chord. In order to use the existing formulae in these cases some engineering effort is required to derive correct hot spot stress. This work can be avoided by using the nominal stress in the chord as the basis for calculating the hot spot stress at the crown position instead of using the axial force in the brace as basis for the analysis. This also extends the validity of the equations for stress concentration factors for T- and Y- joints in design standards. The proposed modification makes it also simpler to include the effect of joint flexibility in a proper way. The basis for a proposed revision of the equations for stress concentration factors for these joints is presented in this paper. It is considered that this modification leads to minor changes of the computer code, but that it will save analysis work for engineers and reduce the possibility of calculating incorrect fatigue lives in tubular frame structures.     

An analysis of weekly out-of-home discretionary activity participation and time-use behavior

Activity-travel behavior research has hitherto focused on the modeling and understanding of daily time use and activity patterns and resulting travel demand. In this particular paper, an analysis and modeling of weekly activity-travel behavior is presented using a unique multi-week activity-travel behavior data set collected in and around Zurich, Switzerland. The paper focuses on six categories of discretionary activity participation to understand the determinants of, and the inter-personal and intra-personal variability in, weekly activity engagement at a detailed level. A panel version of the Mixed Multiple Discrete Continuous Extreme Value model (MMDCEV) that explicitly accounts for the panel (or repeated-observations) nature of the multi-week activity-travel behavior data set is developed and estimated on the data set. The model also controls for individual-level unobserved factors that lead to correlations in activity engagement preferences across different activity types. To our knowledge, this is the first formulation and application of a panel MMDCEV structure in the econometric literature. The analysis suggests the high prevalence of intra-personal variability in discretionary activity engagement over a multi-week period along with inter-personal variability that is typically considered in activity-travel modeling. In addition, the panel MMDCEV model helped identify the observed socio-economic factors and unobserved individual specific factors that contribute to variability in multi-week discretionary activity participation.

车载作用下土基永久变形机理及影响因素分析

论述了土基永久变形的发展机理及其危害性,并从内、外因两个方面分析了影响土基永久变形的重要因素,为利用室内重复荷载三轴试验研究路基土的永久变形特性提供了参考依据。