Seatbelt wearing rates in middle income countries: A cross-country analysis

In settings with low seatbelt use prevalence, self-reported seatbelt use estimates often lack validity, and routine observational studies are scarce. In this paper, we aim to describe the prevalence of seatbelt use and associated factors in drivers and front-seat passengers across eight sites in four countries (Egypt, Mexico, Russia, Turkey) using observational studies as well as to produce estimates of country-level and site-level variance. As part of the Bloomberg Philanthropies Global Road Safety Program, data on driver and passenger seatbelt use across four middle-income countries was collected between October 2010 and May 2011 (n = 122,931 vehicles). Logistic regression and Intraclass Correlation Coefficient analyses for sites- and country-level clustering were performed. We found high variability of seatbelt wearing rates ranging from 4 to 72% in drivers and 3–50% in front-seat passengers. Overall, average seatbelt wearing rates were low (under 60% in most sites). At the individual level, older and female drivers were more likely to wear seatbelts, as well as drivers of vehicles transiting at times of increased vehicle flow. We also found that 26–32% and 37–41% of the variance in seatbelt use among drivers and front-seat passengers respectively was explained by differences across sites and countries. Our results demonstrate that there is room for improvement on seatbelt use in middle-income countries and that standardized cross-country studies on road safety risk factors are feasible, providing valuable information for prevention and monitoring activities.     

Time-dependent constitutive modeling of drive belts – I. The effect of geometry and number of loading cycles

This paper presents constitutive modeling of dynamically loaded elastomeric products such as power transmission belts. During the normal operation of the belts certain segments of the belt structure are loaded with a tooth-like periodic (cyclic) loading. When the time-dependent properties of the elastomeric material “match” the time-scale of the dynamic loading a strain accumulation process occurs. The critical angular velocity is proportional to the ratio of the belt length to the common diameters of the pulleys. The magnitude of the strain accumulated in each loading cycle decreases with an increase in belt length. For a given belt geometry the critical angular velocity increases with the number of loading cycles. At the same time the magnitude of the accumulated strain decreases non-linearly as the number of loading cycles increases. However if the belt operates at or in the close vicinity of its critical angular velocity it will almost certainly fail! The critical angular velocity depends on the material retardation time (location in the frequency spectrum), while the magnitude of the accumulated strain is dictated by the strength of the corresponding discrete spectrum lines. Thus, the mechanical spectrum of the elastomeric material from which the belt is constructed is the most important material function for predicting the durability of drive belts and similarly dynamically loaded elastomeric products.     

塔河油田七区油气区带划分与评述

塔河油田七区碳酸盐岩储层埋藏深，厚度变化大，储集层非均质性强，孔，缝，洞系统变化大，给储层对比和寻找油气分布规律带来较大困难。通过测井资料的纵，横向对比与追踪，结合地震，钻井及试采资料，依据地层岩性，储层特性，构造及断裂特征，发现现今岩溶地貌特征及古构造运动及同期产生的断裂和古岩溶发育特征的显露，三者有机结合，对该区进行了油气区带划分与评价，从中找出了区带特点和高产油气区带。     

Appropriate frontal barrier tests for belted occupants

Vehicle damage from frontal impacts was classified and investigated together with injuries sustained by belted front seat occupants. The sample consisted of 1872 frontal crashes from the Midlands of England. Analysis focused on impacts with broad objects that might conceivably be simulated by a barrier test. Two asymmetrical front-end damage patterns were commonly identified, and these gave the greatest rates of nonminor (Abbreviated Injury Scale (AIS) ≥ 2) injuries in a range of Estimated Test Speeds from 35 to 52km/h which is the regime of current legislative crash tests. The most injurious type involved oblique damage caused by a substantial overlap of the struck object. The other type was from a small overlap. Objects struck and passenger compartment intrusions were compared. Appropriate asymmetrical and deformable barrier concepts were discussed. Other findings were connected with the future role of full face barriers as used in current tests such as Federal Motor Vehicle Safety Standard 208. Fuller overlaps ( > 50%) tended to give more torso injuries rated ≥ AIS 2 caused by seat belt loads and, at high speeds (53–79km/h), caused the most fatalities. Full overlaps (100%) rarely resulted in symmetrical intrusion into the passenger compartment.     

高速龙带的应用

通过对高速龙带的性能比较，结构介绍，提出了高速龙带的设计选用和正确安装，调整、使用的方法；从而提高高速龙带在纺织机械及其它设备上的使用性能和寿命。     

松辽盆地北部断裂演化序列与反转构造带形成机制

立足松辽盆地北部区域地震解释,从分析断裂几何学特征着手,以断裂形成演化过程为主线,系统剖析了盆地演化不同阶段断裂的变形机制,揭示了反转构造带的形成机制及其对油气运聚成藏的指示作用。研究表明,松辽盆地北部断裂演化经历了断陷期的持续伸展变形、拗陷期的持续张扭变形和反转期的连续挤压构造反转变形。盆地晚期构造反转变形是在基底深大断裂、断陷期北西—南东向引张应力场形成的半地堑以及拗陷期近东西向拉张应力场形成的多方位断裂密集带基础上开始演化的。反转期左旋压扭变形场与断陷半地堑、基底深大断裂共同控制了次级背斜带和反转构造带的形成,大庆长垣地区受北北东向断陷半地堑和北北东向基底深大断裂双重影响,反转程度最大,将反转期初始北东向的次级背斜带最终连成北北东向的反转构造带,同时将拗陷期形成的以近南北向为主体的断裂密集带旋转改造成以北西—北北西向为主体的断裂密集带展布格局。     

新型自粘型止水带抗窜水渗漏性能试验研究

介绍了一种新型自粘型止水带的主要性能特点,提出了一种止水带抗窜水渗漏试验的新方法,进行了普通止水带和自粘型止水带的抗窜水渗漏性能对比试验,得出相关结论以期有力推动新型自粘型止水带的推广应用。     

公路隧道施工防排水施工控制要点

通过阐述公路隧道设计规范关于隧道防排水的有关规定,从几个方面总结了公路隧道防排水施工控制要点,从而确保隧道防排水工程质量,从根本上消除隧道病害和延长隧道寿命。     

露天煤矿生态恢复环节作业方式与参数确定方法

提出采用绿色开采技术是解决露天矿生态环境问题的根本途径,在原有工艺环节基础上加入“生态恢复”环节,形成露天煤矿绿色开工艺系统。对生态恢复环节的作业方式和参数等进行研究,定义了生态恢复作业面、土地平整带等概念。土地平整带的划分方式按与排土台阶的关系分为:平行划分和垂直划分。生态恢复环节主要作业参数为:生态恢复作业面的面积、土地平整带宽度、土地恢复工作线长度、平均填方厚度或挖方深度(填方为正、挖方为负)、土地恢复水平跟进速度,建立了作业参数计算的数学模型,确定了生态恢复环节的设备类型及其生产能力计算方法。以准格尔黑岱沟露天煤矿内排土场土地恢复为例进行了设计,确定了土地恢复工作面的划分、生态恢复环节工艺及设备类型,确定了作业参数。     

The influence of natural ageing processes on the strength parameters of steel cord conveyor belts

Abstract

The article presents an analysis of the influence of the natural ageing time on the strength parameters of steel cord conveyor belts. The investigated phenomena include the influence of temperatures both above and below 0 °C, as well as exposure to sun, rain and snow. The tests were performed on conveyor belts which have been operated in the Be?chatów lignite mine for 30 years, transporting ROM material. The tests included adhesion of the steel cords to the belt’s core rubber and the tensile strength of both the carry and the pulley covers. The obtained results allowed determining the number of years after which belts operated in mines lose their properties. The results also indicate how long a conveyor belt, after launching it into service, retains such strength parameters that enable its further usage after revulcanisation. This information is of significant importance for the splicing and regeneration processes.