An analysis of driving and working hour on commercial motor vehicle driver safety using naturalistic data collection

Current hours-of-service (HOS) regulations prescribe limits to commercial motor vehicle (CMV) drivers’ operating hours. By using naturalistic-data-collection, researchers were able to assess activities performed in the 14-h workday and the relationship between safety-critical events (SCEs) and driving hours, work hours, and breaks. The data used in the analyses were collected in the Naturalistic Truck Driving Study and included 97 drivers and about 735,000 miles of continuous driving data. An assessment of the drivers’ workday determined that, on average, drivers spent 66% of their shift driving, 23% in non-driving work, and 11% resting. Analyses evaluating the relationship between driving hours (i.e., driving only) and SCE risk found a time-on-task effect across hours, with no significant difference in safety outcomes between 11th driving hour and driving hours 8, 9 or 10. Analyses on work hours (i.e., driving in addition to non-driving work) found that risk of being involved in an SCE generally increased as work hours increased. This suggests that time-on-task effects may not be related to driving hours alone, but implies an interaction between driving hours and work hours: if a driver begins the day with several hours of non-driving work, followed by driving that goes deep into the 14-h workday, SCE risk was found to increase. Breaks from driving were found to be beneficial in reducing SCEs (during 1-h window after a break) and were effective in counteracting the negative effects of time-on-task.     

现场总线技术在化工煤场自控系统中的应用

介绍了化工煤场翻车机卸车系统和皮带运输系统现场总线网络硬件配置及ControlNet网、PROFlbusDP网现场总线技术特点和通信的实现,系统投入运行后稳定、可靠满足了生产过程控制的需要。     

纵向静磁场对单晶高温合金DD483组织及蠕变性能的影响

在静磁场下进行高温合金DD483的定向凝固实验,研究了不同磁场强度对单晶镍基高温合金DD483凝固组织枝晶形貌、合金元素偏析系数、析出相和蠕变性能的影响.结果表明:纵向静磁场的施加使高温合金DD483单晶生长性受到破坏,强的磁场使得枝晶定向生长形态受到破坏,形成“雀斑组织”,对一次枝晶间距影响不大.施加磁场使得该单晶合金中合金元素的偏析降低;也使单晶高温合金DD483凝固态组织中γ’析出尺寸降低、碳化物和共晶组织尺寸和含量显著减小.同时磁场对该合金的单晶性和枝晶的定向生长行为的破坏使得合金的蠕变性能降低.     

A practical image reconstruction and processing method for symmetrically off-center detector CBCT system

CBCT scanners have been widely used in angiography, radiotherapy guidance, mammography and oral maxillofacial imaging. To cut detector size, reduce manufacturing costs and radiation dose while keeping a reasonable FOV, the flat panel detector can be placed off-center horizontally. This scanning configuration extends the FOV effectively. However, each projection is transversely truncated, bringing errors and artifacts in reconstruction. In this paper, a simple but practical method is proposed for this scanning geometry based on truncation compensation and the modified FDK algorithm. Numerical simulations with jaw phantom were conducted to evaluate the accuracy and practicability of the proposed method. A novel CBCT system for maxillofacial imaging is used for clinical test, which is equipped with an off-center small size flat panel detector. Results show that reconstruction accuracy is acceptable for clinical use, and the image quality appears sufficient for specific diagnostic requirements. It provides a novel solution for clinical CBCT system, in order to reduce radiation dose and manufacturing cost.     

屏蔽层对电缆寄生参数的影响分析

电缆作为连接各种电子设备必不可少的元件,是电磁兼容设计的重点问题之一,大部分电磁干扰敏感问题、电磁干扰发射问题、信号串扰问题都是电缆产生的。针对电缆是否应用屏蔽层的电磁干扰问题进行对比分析,通过运用Q3D软件对电缆的寄生参数进行提取并得到其场分布图,建立电缆的等效电路模型,使用6500B阻抗分析仪对于屏蔽电缆和非屏蔽电缆的寄生参数进行测量验证,分析了屏蔽电缆的接地原因。研究结果表明:屏蔽电缆的寄生参数有所增加,但是其对辐射干扰有明显的抑制作用。     

Identification and Field Evaluation of Grape Shoot Volatiles Attractive to Female Grape Berry Moth (<Emphasis Type="Italic">Paralobesia viteana</Emphasis>)

Solid-phase microextraction (SPME) and gas chromatography coupled with electroantennographic detection (GC-EAD) were used to identify volatile compounds from shoots of riverbank grape (Vitis riparia) that attract the female grape berry moth (GBM, Paralobesia viteana). Consistent EAD activity was obtained for 11 chemicals: (Z)-3-hexen-1-yl acetate, (E)-linalool oxide, (Z)-linalool oxide, nonanal, linalool, (E)-4,8-dimethyl-1,3,7-nonatriene, methyl salicylate, decanal, beta-caryophyllene, germacrene-D, and alpha-farnesene. In flight-tunnel tests that involved female GBM and rubber septa loaded with subsets of these 11 compounds, we found that both the 11-component blend and a seven-component blend, composed of (E)-linalool oxide, (Z)-linalool oxide, nonanal, (E)-4,8-dimethyl-1,3,7-nonatriene, decanal, beta-caryophyllene and germacrene-D, elicited equivalent levels of upwind flight as freshly cut grape shoots. The removal of any of the seven compounds from the seven-component blend resulted in a significant decrease in female upwind flight responses. In a field trial with these two synthetic blends, traps equipped with either blend captured more female GBM compared to traps baited with hexane only (control), although the number of females caught was generally low. There were no differences in the number of males captured among treatments. Although in flight-tunnel trials, moths readily flew upwind to both grape shoots and rubber septa loaded with the best lures, they landed on shoots but not on rubber septa. Coupled with relatively low field catches, this suggests that additional host finding cues need to be identified to improve trap efficacy.     

Si field emitter arrays coated with thin ferroelectric films

This paper demonstrates novel approach on Si field emitter arrays (FEAs) coated with thin ferroelectric films for vacuum microelectronic applications, which exhibit enhanced electron emission behaviors. The films were deposited using sol–gel and sputtering process, respectively. In sol–gel approach, the emission behavior is highly correlated to the crystallinity of (Ba,Sr)TiO₃ (BST) layer. The interfacial reaction between Si and BST film would deteriorate the crystallinity of the films, and in turn impede the electron emission from silicon tips. The film thickness and the dopants also affect the emission behaviors significantly. In sputtering process, the nitrogen-incorporated SrTiO₃ (STO) films are deposited with eliminated interfacial due to relatively lower processing temperature. The enhanced emission characteristics are highly correlated with nitrogen-incorporation and film thickness. These encouraging results have offered great promise for the application of ferroelectric films in field emission devices.     

不同流量条件下导叶式旋流器内部流动的数值模拟

应用Fluent软件和雷诺应力模型(RSM)对导叶式旋流器内部三维强旋湍流流动进行了数值模拟,考察了不同入口流量对旋流器内速度场的影响。研究结果表明,旋流器内径向速度远小于切向速度和轴向速度,锥段的切向速度明显小于柱段的切向速度;随着流量的增加,各向速度均增加,最大切向速度的分布直径并不随流量的变化而改变,且最大切向速度位于准自由涡与准强制涡的分界处。通过计算还发现,在旋流器圆柱段存在循环流和短路流,锥段的上行区域均小于柱段,而且截面越靠底流口,上行区域越小。     

Removal of particulate matter from an air stream by a packed dielectric barrier discharge

This study elucidates the feasibility of using a packed dielectric barrier discharge approach to remove particulate matter from an air stream. The experimental results reveal that the particle removal efficiency of the packed dielectric barrier discharge system rose to 92.2% for 0.3 μm particles as the discharge voltage was increased to 20 kV at an operating frequency of 60 Hz. Only when the discharge voltage was sufficiently high to remove particulate matter did the particle removal efficiency increase with the operating frequency. The power required to adjust the discharge voltage was less than that required to adjust the operating frequency at the particular removal efficiency. Accordingly, energy can be saved in a packed dielectric barrier discharge system by adjusting the discharge voltage rather than the operating frequency to remove particulate matter from the air stream.     

气缸内迷宫密封流场特性研究

建立了迷宫式活塞压缩机的迷宫密封数学模型,运用FLUENT软件对其气缸迷宫内的气体流动进行了计算模拟,并对迷宫压缩机活塞与气缸壁间的迷宫流场进行了分析。