消除自硬砂的铸造缺陷

铸造厂都是想以较低的生产成本来生产出高质量的铸件.除考虑工艺、金属及铸件的类型外,铸造都是以造型和浇注来达到这个目的的. 对于自硬砂造型生产而言,要达到这个目的经常会遇到意外的障碍,这些障碍来自造型粘结剂和树脂、耐火涂料及再生砂.因此,自硬砂铸造工作者对铸件缺陷的检查、辨别、消除的检测能力应达到与其获得的金属铸造知识一样多的程度.     

Possible remedies for intact stability hazards involving contemporary small inland passenger ferries in Bangladesh

On the basis of previous studies, a series of hazards involving the typical small inland passenger ferries operating in inland Bangladeshi waters have been identified. In particular, stormy weather conditions, overloading, and the risk of crowding to one side have been determined as the typical events that are likely to lead to capsizing in the intact condition. In this article, possible hazard mitigation measures are discussed, both from the regulatory and from the design point of view, for a small inland ferry that is very similar to one that actually capsized in the past. The addressed design options involve ballasting and hull modification by means of additional buoyancy above the waterline. From a regulatory point of view, it is proposed that the present weather criterion in force in Bangladesh be modified by increasing the wind speed to be accounted for and by considering the concurrent effects of wind, rolling, and the crowding of people to one side.     

A rational analysis of intact stability hazards involving small inland passenger ferries in Bangladesh

The safety of inland passenger vessels operating in Bangladesh has been investigated. By thorough analysis of past accident data, the main causes of intact stability failures have been determined: adverse weather conditions and overloading, likely resulting in crowding to one side. Historical series of wind data were gathered and their analysis suggests that an increase in the wind speed presently used in the Weather Criterion in force in Bangladesh could be advisable. A model of a small passenger ship typically operated in Bangladesh has been analyzed in order to identify the most relevant hazards under intact ship conditions. A strongly jeopardizing effect of overloading under intact ship conditions has been detected when analyzing the hazard from the crowding of people to one side.     

On the performance of rheological shock absorber models in full vehicle simulation

A comparative study of the performance of three rheological automotive shock absorber models as well as of an extended force-velocity relation in full vehicle simulation is performed. Simulation results for both the shock absorber test rig and a full vehicle crossing a single obstacle are compared with measured data. While the gain of accuracy by the extended force-velocity relation is marginal, the rheological models in general yield a noticeable improvement, which, however, in full vehicle simulation is less significant than in test rig simulation. Among the rheological models studied here, the one consisting of a nonlinear spring-dashpot element with an element modelling friction by a continuous transition from the compression to the extension range in parallel and a quadratic approximation of the static gas force exhibits the best global performance.     

A cluster analysis of cyclists in Europe: common patterns,behaviours, and attitudes

Transportation - This study uses cluster analysis on a sample of regular cyclists from six European countries (the U.K., the Netherlands, Sweden, Hungary, Italy, and Spain) to shed light on common...     

Factors contributing to bicycle–motorised vehicle collisions: a systematic literature review

Bicycle–motorised vehicle (BMV) collisions account for the majority of the recorded bicyclists’ fatalities and serious injuries. This systematic review intends to examine the main factors contributing to BMV collisions. We performed a comprehensive literature review on Scopus, TRID, ProQuest, and Web of Science databases. Fifty-nine English-language peer-reviewed articles met the eligibility criteria and were included in the final analysis. The main factors contributing to BMV collisions identified were classified in accordance with a recently published conceptual framework for road safety. The majority of studies have identified factors related to road users’ behaviour (59.3%) and infrastructure characteristics (57.6%). A minority of studies identified variables related to exposure (40.7%) and vehicles (15.3%) as contributor factors to BMV collisions. A small but significant proportion of studies (20.3%) provided evidence that environmental factors may also play a role, although to a lesser extent, in determining BMV collisions. In addition to the three factors comprised in the applied conceptual framework for road safety, we identified environmental conditions as a category of factors contributing to BMV collisions.