煤炭表面改质技术及设备在东曲矿选煤厂的应用

阐述了一种新型的采用高剪切力的煤炭表面改质技术及设备在东曲矿选煤厂的应用,该厂通过对表面改质机内部结构与工作过程的分析研究,以及单机试验和工业运行试验,初步探讨了表面改质机的作用机理,经现场连续带负荷生产后,能显著提高浮选速度和精煤回收率.     

Fractions of fatal crashes attributable to speeding: Evolution for the period 2001–2010 in France

Road safety is a major concern in the West, especially in France. Among all the established risk factors for fatal crashes, speed is specific in two ways: every road-user is exposed to it, and it increases not only crash rates but also the severity of crashes. Thus, speed regulation is of primary importance in road-safety policy and has also generated much public debate. To contribute to this debate, we constructed a power-model which relates the number of fatal crashes to speed raised to the power four. Despite its simplicity, this model fitted the data well. Notably, it enabled the fractions of fatal crashes attributable to various levels of speeding to be estimated. Data for secondary roads over the period 2001–2010 showed that the fraction of fatal crashes attributable to high-level speeding (>20 kph over the speed limit) decreased from 25% to 6% and that attributable to medium-level speeding (10–20 kph over the speed limit) decreased from 13% to 9%, whereas that attributable to low-level speeding progressively increased from 7% to 13%. Similar trends were observed on main roads. These results highlight the effectiveness of the speed regulation policies introduced during the study period with respect to high-level speeding. They also suggest that future policy should focus on low and medium-level speeding in order further to reduce road deaths significantly, since these levels now correspond to the major fraction of fatal crashes.     

探讨桥梁工程赶工措施费的计算

由于桥梁工程建设周期长、受到当地征地拆迁等因素的干扰和影响,致使原定的计划竣工时间不能保证。而业主往往要求按时甚至提前竣工,就要求施工单位修订施工进度计划,采取各项赶工技术措施,由此增加承包人赶工措施费用投入。为了保证承包人成本顺利回收,更好的完成赶工费用的计算工作,本文以福州市某大桥工程赶工措施费的计算实例对赶工费用进行探讨。     

The observed effects of teenage passengers on the risky driving behavior of teenage drivers

The association between teenage passengers and crash risks among young drivers may be due to risky driving behavior. We investigated the effect on two measures of risky driving in the presence of young male and female passengers. Vehicles exiting from parking lots at 10 high schools were observed and the occupants were identified by gender and age (teen or adult). At a nearby site, the speed and headway of passing traffic were recorded using video and LIDAR technology. Teenage drivers drove faster than the general traffic and allowed shorter headways, particularly in the presence of a male teenage passenger. Both male and female teenage drivers allowed shorter headways (relative to no passenger or a female passenger) in the presence of a male teenage passenger, while the presence of a female teenage passenger resulted in longer headways for male teenage drivers. Overall, the observed rate of high risk driving (defined as speed > or =15 mph or more above the posted speed limit and/or headway of < or =1.0 s) for the teen male driver/male passenger condition was about double that of general traffic. In conclusion, the presence of male teenage passengers was associated with risky driving behavior among teenage drivers.     

OBB层次结构及其应用加速算法的研究

层次包围盒在碰撞检测中的应用对于提高碰撞检测精确度以及减少碰撞检测复杂度起着十分重要的作用。该文介绍了OBB包围盒的计算、相交测试以及构造方法,将一种加速碰撞检测搜索算法与其结合,并且讨论了时间复杂度。     

Personality, risk aversion and speeding: an empirical investigation

Evidence suggests that in addition to demographics, there are strong relationships between facets of drivers’ personality (e.g., aggression, thrill-seeking, altruism), aversion to risk and driving behaviour, particularly speeding. However, evidence is muted by the reliance on self-reported driving behaviour, which is thought to not accurately reflect actual driving behaviour. This paper reports on a study of 133 drivers in Sydney, who were asked to complete a short survey to develop their personality and risk aversion profiles and self-reported speeding behaviour. A Global Positioning System (GPS) device was then installed in their vehicle for several weeks as part of a major investigation of driving behaviour from which empirical measures of speeding are derived. Among the most pertinent findings are: (1) the tendency for drivers to both under and over-estimate their propensity to speed, (2) significant heterogeneity in speeding with a small, but notable number of drivers exceeding the limit for more than 20 percent of the distance driven, (3) weak relationships between the personality/risk-aversion measures and actual speeding, and (4) the suggestion that different personality traits appear to influence behaviour in different situations both from self-reported and actual speeding behaviour.     

硬质合金YG8高速磨削工艺试验研究

采用树脂结合剂金刚石砂轮,对硬质合金YG8进行了高速磨削工艺试验研究,测得了不同砂轮线速度、磨削深度和工作台速度条件下的磨削力和表面粗糙度,并对磨削的表面形貌进行了观测,揭示了硬质合金YG8高速磨削的材料去除机理。试验结果表明:将高速磨削技术应用于硬质合金材料的加工是一种切实可行的加工方法,能得到较好的表面质量并提高加工效率。随着砂轮线速度的增加,或者工作台速度和磨削深度的减小,磨削的最大未变形切屑厚度减小,磨削力减小,材料的比磨削能增加,使得工件的加工表面质量得到改善。     

Stability of risky driving from late adolescence to early adulthood

This study examined the stability of risky driving behaviour from late adolescence to early adulthood among 823 young Australian drivers participating in an ongoing longitudinal study. This issue was explored by examining the stability of risky driving between the ages of 19–20 and 23–24 years (1) across the cohort and (2) among individuals. Focusing on cohort-wide trends, a modest reduction in the occurrence of speeding was observed across the sample between 19–20 and 23–24 years. However, drink-driving increased markedly over this period, and driving without a seatbelt or helmet for part of a trip also rose. Rates of other risky driving behaviours remained relatively unchanged. With regard to trends among individuals, while a decrease was evident in the risky driving propensities of many who had been classified as moderate or high risky drivers at age 19–20, 48% of the former group, and 77% of the latter group, still exhibited risky driving tendencies at 23–24 years. Together, these findings suggest a fair degree of stability in risky driving from late adolescence to early adulthood among this sample of Australian youth, highlighting the continuing need for road safety initiatives targeting young drivers beyond their first years of licensure.     

Speeding by young novice drivers: What can personal characteristics and psychosocial theory add to our understanding?

Purpose

Young novice drivers continue to be overrepresented in fatalities and injuries arising from crashes even with the introduction of countermeasures such as graduated driver licensing (GDL). Enhancing countermeasures requires a better understanding of the variables influencing risky driving. One of the most common risky behaviours performed by drivers of all ages is speeding, which is particularly risky for young novice drivers who, due to their driving inexperience, have difficulty in identifying and responding appropriately to road hazards. Psychosocial theory can improve our understanding of contributors to speeding, thereby informing countermeasure development and evaluation. This paper reports an application of Akers’ social learning theory (SLT), augmented by Gerrard and Gibbons’ prototype/willingness model (PWM), in addition to personal characteristics of age, gender, car ownership, and psychological traits/states of anxiety, depression, sensation seeking propensity and reward sensitivity, to examine the influences on self-reported speeding of young novice drivers with a Provisional (intermediate) licence in Queensland, Australia.

Method

Young drivers (n = 378) recruited in 2010 for longitudinal research completed two surveys containing the Behaviour of Young Novice Drivers Scale, and reported their attitudes and behaviours as pre-Licence/Learner (Survey 1) and Provisional (Survey 2) drivers and their sociodemographic characteristics.

Results

An Akers’ measurement model was created. Hierarchical multiple regressions revealed that (1) personal characteristics (PC) explained 20.3%; (2) the combination of PC and SLT explained 41.1%; (3) the combination of PC, SLT and PWM explained 53.7% of variance in self-reported speeding. Whilst there appeared to be considerable shared variance, the significant predictors in the final model included gender, car ownership, reward sensitivity, depression, personal attitudes, and Learner speeding.

Conclusions

These results highlight the capacity for psychosocial theory to improve our understanding of speeding by young novice drivers, revealing relationships between previous behaviour, attitudes, psychosocial characteristics and speeding. The findings suggest multi-faceted countermeasures should target the risky behaviour of Learners, and Learner supervisors should be encouraged to monitor their Learners’ driving speed. Novice drivers should be discouraged from developing risky attitudes towards speeding.     

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