How would increasing seat belt use affect the number of killed or seriously injured light vehicle occupants?

The expected effects of increasing seat belt use on the number of killed or seriously injured (KSI) light vehicle occupants have been estimated for three scenarios of increased seat belt use in Norway, taking into account current seat belt use, the effects of seat belts and differences in crash risk between belted and unbelted drivers. The effects of seat belts on fatality and injury risk were investigated in a meta-analysis that is based on 24 studies from 2000 or later. The results indicate that seat belts reduce both fatal and non-fatal injuries by 60% among front seat occupants and by 44% among rear seat occupants. Both results are statistically significant. Seat belt use among rear seat occupants was additionally found to about halve fatality risk among belted front seat occupants in a meta-analysis that is based on six studies. Based on an analysis of seat belt wearing rates among crash involved and non-crash involved drivers in Norway it is estimated that unbelted drivers have 8.3 times the fatal crash risk and 5.2 times the serious injury crash risk of belted drivers. The large differences in crash risk are likely to be due to other risk factors that are common among unbelted drivers such as drunk driving and speeding. Without taking into account differences in crash risk between belted and unbelted drivers, the estimated effects of increasing seat belt use are likely to be biased. When differences in crash risk are taken into account, it is estimated that the annual numbers of KSI front seat occupants in light vehicles in Norway could be reduced by 11.3% if all vehicles had seat belt reminders (assumed seat belt wearing rate 98.9%), by 17.5% if all light vehicles had seat belt interlocks (assumed seat belt wearing rate 99.7%) and by 19.9% if all front seat occupants of light vehicles were belted. Currently 96.6% of all (non-crash involved) front seat occupants are belted. The effect on KSI per percentage increase of seat belt use increases with increasing initial levels of seat belt use. Had all rear seat occupants been belted, the number of KSI front seat occupants could additionally be reduced by about 0.6%. The reduction of the number of KSI rear seat occupants would be about the same in terms of numbers of prevented KSI.     

Radiation damage behavior of carbon/carbon composite in Low Earth Orbit environment

To understand the degradation behavior of Carbon/Carbon(C/C) composite in LEO radiation environment, groups of 2D-C/C composites samples were exposed to ground-based Low Earth Orbit(LEO) simulating facilities. The LEO radiating environment covers part of Van Allen inner belt, which contains atomic oxygen(AO) and high-energy proton radiating regions. These two kinds of radiating sources were arranged for simulating the real LEO radiating conditions regarding to the first orbit movement speed of serving space shuttles. Changes of micro-structure, mass loss, surface roughness, chemical construction and thermal physical properties after environmental assessment were analyzed and compared to understand the damage behavior of LEO radiation on C/C composite. It was found that AO is the main factor of mass loss in LEO radiating particles. The charged high-energy protons have an aggravating damage ability with energetic AO, damage situations of degree in orbit down process is more serious than in orbit rising process. The LEO radiation damage mechanisms of C/C composite are revealed and expounded either.     

Assessment of the static fit of automobile lap-belt systems on front-seat passengers

While automobile seat belts are recognized as reducing injury in frontal collisions, the lap belt can cause injury to the abdominal contents during impact. A lap belt which is malpositioned, i.e., above the anterior superior iliac spines (ASIS) of the pelvis before impact, is suggested as a causative factor in many of these injuries. A questionnaire was completed by 198 adult passengers on lap-belt fit as well as vehicle, anthropometric and behavioural factors. All measures were self-reported. The fit of automobile seat belts was also investigated in the laboratory to determine some of the factors thought important in the pre-impact position of the lap belt. Seven factors, subject size, subject sitting posture, clothing thickness, vehicle configuration, vehicle seat position, seat back angle and the handling of the belt by the occupant, were assessed on 51 subjects sitting in six simulated vehicles. The sample purposely included a disproportionate number of tall, short, heavy and thin subjects.

The questionnaire responses indicated that a high proportion (49%) of lap belts were found to be malpositioned in a normal sitting posture. Moving around in the seat, especially slouching, greatly increased the proportion of malpositions. It was noteworthy that wearing a heavy winter coat did not cause belt malposition. A high incidence of malpositioned lap belts was also found in the laboratory study with 42% of the belts having their centre-lines above the ASIS and 89% having part of the belt overlying the ASIS in a normal upright seated position with the seat in the middle of its fore/aft movement. Slouching in the seat significantly increased this proportion. The malposition rate was adversely affected by a forward seat position in a significant manner. There was a large increase in the malposition rate when the occupant attached the belt compared to when the experimenter attached it, with malposition rates of 43% and 19% respectively in the rearmost seat position. There was no statistically significant effect of clothing thickness on belt fit. Although statistically significant correlations between belt inclination and malposition were found, no clear-cut belt-angle existed above which satisfactory fit existed.     

输送带用钢丝绳生产及技术进步

介绍输送带用钢丝绳的主要生产控制及使用要求。从捻制质量、结构选择、力学性能以及粘合力和镀层质量控制等方面介绍输送带用钢丝绳的生产工艺控制以及各生产工序质量控制的注意事项,指出钢丝绳弯曲疲劳、输送带张紧装置造成胶带张力过大和张力分布不均匀、外力过大、腐蚀、异物损伤以及接头抽丝是输送带用钢丝绳使用过程中断裂的主要原因,保证钢丝绳储存质量和改善钢丝绳接头工艺有助于减少输送带生产过程中的钢丝绳消耗。对输送带用钢丝绳的技术进步做了展望。     

一次成型环状输送带增强骨架研发

在机上织造成环、无需机下接头的输送带增强骨架,称为一次成型环状增强骨架。环状增强骨架由于不存在接头,具有带体厚度波动小、噪声低、力学性能优等特点。将织物组织结构参数相同的环状增强骨架、传统增强骨架制备成输送带,对两者的厚度波动、噪声和拉伸强度进行试验和对比分析。结果表明,环状增强骨架输送带的厚度波动小于传统增强骨架输送带,噪声低于传统增强骨架输送带,力学性能明显优于传统增强骨架输送带。     

带式输送机空载功率计算方法探讨

带式输送机空载功率是鉴定制造、安装质量的重要指标。介绍一种比较准确和简便的空载功率计算方法。     

带式输送机弯曲段曲率半径的确定

通过输送机平面转弯段的受力分析,改进了平面转弯带式输送机转变处的布置结构,经使用,输送带在运行至弯曲段时能自动进行居中调节,效果较好。     

平面转弯带式输送机技术方案浅析

主要介绍平面转弯带式输送机技术方案的设计计算及实现平面转弯的技术要点,保证托辊具有一定的安装支撑角,构成内曲线抬高角,增大成槽角,对线路进行合理设计,使普通带式输送机实现了平面转弯运行,并确定转弯半径和驱动功率,又用类比法对驱动装置进行了选型。具有良好的推广应用前景。     

梁板后浇带模板断开早拆施工技术

在高层建筑混凝土施工过程中,将模板及支撑架体在后浇带处断开,有效截断混凝土泵送时产生脉冲振动引起的模板和模架的振动,减少对已经初凝的混凝土水泥石结构的破坏.后浇带处采用“多种模板主梁早拆模板支撑头”,减少拆模时的二次支顶.在后浇带处不铺设下部模板,便于后浇带两侧混凝土凿毛和清理.后浇带封闭安装模板,操作简易、适用性强,易于推广.