特殊地质条件下流动相原油在沿海土-水系统中的运移过程及机制研究

原油作为主要能源之一对现代社会的重要作用不言而喻,但其所带来的污染危害同样不容忽视.通过自制的有机玻璃水槽,建立模型模拟自然地层的非均质性,模拟了原油在沿海土-水系统中的运移过程,探讨了局部非渗透性透镜体、底部隔水层、土壤初始含水率、土壤质地、岩性突变界面对原油在砂土中运移速度和路径的影响.结果表明,局部非渗透性透镜体和底部隔水层对原油的运移具有阻碍作用,会改变其运动速度和路径.在一定范围内,土壤初始含水率越高,原油的侧向运移速率和垂向运移速率越大(模拟成层性土层中原油垂向运移速率随含水率增大,由0.43 cm·min~(-1)增大到1.00 cm·min~(-1),在低含水率区域原油侧向运移速率分别为0.08 cm·min~(-1)(粗-细界面)和0.10 cm·min~(-1)(细-粗界面),而在含水率较高的区域则为0.14 cm·min~(-1)),而过高的含水率又会阻碍原油的运移.土壤孔隙越大,垂向运移越快,侧向运移越慢,反之,垂向运移越慢,侧向运移越快(模拟成层性土层中,原油在粗砂中的垂向平均运移速率为0.54 cm·min~(-1),而在细砂中仅为0.33 cm·min~(-1),自然泄漏时原油在粗砂中的最大扩散范围为9.10 cm,在细砂中为12.50 cm).原油在土壤中运移遇到岩性突变界面时,会产生聚集效应,在聚集处产生侧向运移,试验中在粗-细界面扩散宽度为6.70 cm,在细-粗界面扩散宽度为29.00 cm.     

窄带水平集法下林火蔓延仿真研究

火焰锋面的追踪是建立林火蔓延模型及预测锋面位置的关键环节。基于水平集法追踪锋面具有求解灵活稳定、易于处理锋面拓扑结构变化的特点。针对传统水平集法重新初始化过程复杂、计算量较大的问题,根据距离函数定义,提出通过形态学膨胀的方法以锋面点为圆心向外膨胀,获得锋面附近窄带内每个点距离锋面的最近距离,重建窄带内的水平集函数,物理意义明确,有效减小了计算量,在此基础上基于林火速度场经验模型模拟了单火源及双火源的锋面蔓延情况。结果表明,该方法能够有效模拟坡度、风速等因素对火焰锋面的影响,为其在林火蔓延模型中的应用提供了基础。     

生物炭对黄绵土水分入渗和持水性能的影响

基于室内一维土柱入渗试验,定容重条件下研究了生物炭粒径(1—2 mm和≤0.25 mm)和添加量(10 g?kg~(-1)、50 g?kg~(-1)、100 g?kg~9-1)和150 g?kg~-1))对扰动黄绵土的水分入渗过程及持水能力的影响。结果表明:生物炭明显降低了黄绵土的入渗能力,黄绵土的湿润锋深度与累积入渗量随着生物炭添加量的增加而降低,且小粒径生物炭对黄绵土入渗能力的降低作用强于大粒径;生物炭明显增加了黄绵土的持水能力,且随添加量增大而增大,小粒径生物炭的促进作用优于大粒径;添加生物炭后黄绵土湿润锋深度与时间关系可用幂函数描述;Kostiakov、Philip、Horton入渗模型均能较好模拟生物炭添加后黄绵土累积入渗量随时间变化,其中,Kostiakov模型拟合精度更高;van Genuchten公式可以用来描述添加生物炭后黄绵土持水特征。该研究结果为添加生物炭后的黄绵土适宜性评价提供了土壤水分方面的参考依据。     

A new method to assess the deformations of internal organs of the abdomen during impact

Objectives: Due to limitations of classic imaging approaches, the internal response of abdominal organs is difficult to observe during an impact. Within the context of impact biomechanics for the protection of the occupant of transports, this could be an issue for human model validation and injury prediction.

Methods: In the current study, a previously developed technique (ultrafast ultrasound imaging) was used as the basis to develop a protocol to observe the internal response of abdominal organs in situ at high imaging rates. The protocol was applied to 3 postmortem human surrogates to observe the liver and the colon during impacts delivered to the abdomen.

Results: The results show the sensitivity of the liver motion to the impact location. Compression of the colon was also quantified and compared to the abdominal compression.

Conclusions: These results illustrate the feasibility of the approach. Further tests and comparisons with simulations are under preparation.     

基于图像的火焰锋面法向速度场测量研究

火焰锋面是火焰的重要组成部分,反映了火焰的燃烧特性。针对传统方法测量火焰锋面速度场分辨率较低的问题,提出来了基于图像法测量火焰锋面法向速度场的方法。使用高速相机拍摄了多帧连续图像,提取火焰锋面,通过最小二乘法拟合锋面的切线,从而计算出每个点的法向速度,并进一步分析了火焰振荡的性质。实验表明该方法能够有效测量双瓦楞纸板产生的火焰在不同时刻的速度场,具有高分辨率、全场测量的特点,为其进一步推广提供了实验基础。     

巷道截面积突变情况下瓦斯爆炸冲击波传播规律的研究

瓦斯爆炸冲击波传播规律是研究冲击波的破坏和伤害机理的前提及依据,笔者利用流体动力学、爆炸动力学理论对巷道截面积突变情况下瓦斯爆炸冲击波传播规律进行理论分析,建立巷道截面积突变情况下冲击波传播的数学模型,得到了冲击波波阵面压力和其他空气动力学参数的表达式,从而得到冲击波波阵面压力过巷道截面积突变面时的变化规律。研究成果丰富了瓦斯爆炸冲击波传播规律理论,对井下瓦斯爆炸安全评价以及制定防灾减灾措施提供了理论基础。     

基于开放式创新的新产品开发模糊前端模型研究

开放式创新模式的出现对企业新产品开发（NPD）过程中模糊前端（FFE）创新活动带来重要影响。本文在对模糊前端、开放式创新以及知识共享等现有研究进行文献综述的基础上,重点对四个经典FFE模型的典型特征、共性与差异、优点与不足进行了系统分析,进而从开放式创新与知识共享的视角,探索并构建提出了FFE的开放式模型。并对该模型的五个重要环节、关键概念及其相互关系进行了界定说明与分析评价,既融入经典模型的深厚积淀,又弥补了传统模型在开放性与知识共享等方面的不足。为解决企业在开放式创新环境下新产品开发FFE阶段面临的新问题提供了很好的理论框架与方法支撑。     

Legislating child restraint usage -Its effect on self-reported child restraint use rates in a central city

Objective

To assess the effect of the newly enacted child passenger safety law, Wisconsin Act 106, on self-report of proper restraint usage of children in Milwaukee's central city population.

Method

A prospective, non-randomized study design was used. The settings used were (a) a pediatric urban health center, and (b) two Women, Infants and Children offices in Milwaukee, Wisconsin. Participants included 11,566 surveys collected over 18 months that spanned the pre-legislation and post-legislation time periods from February 2006 through August 2008.

Results

The study set out to assess appropriate child passenger restraint. The results showed that the changes in adjusted proper restraint usage rates for infants between the pre-law, grace period, and post-fine periods were 94%, 94%, and 94% respectively. For children 1-3 years old, the adjusted proper usage rates were 65%, 63%, and 59%, respectively. And for children 4-7 years old, the rates were 43%, 44% and 42%, respectively. There was a significant increase in premature booster seat use in children who should have been restrained in a rear- or forward-facing car seat (10% pre-law, 12% grace period, 20% post-fine; p < 0.0005). There was no statistically significant change over time in unrestrained children (2.1%, 1.7%, 1.7%, p = 0.7, respectively).

Conclusions

The passage of a strengthened child passenger safety law with fines did not significantly improve appropriate restraint use for 0-7 year olds, and appropriate use in 1-7 year olds remained suboptimal with a majority of urban children inappropriately restrained. Although the number of unrestrained children decreased, we identified an unintended consequence of the legislation - a significant increase in the rate of premature belt-positioning booster seat use among poor, urban children.

Impact on Industry

The design of child restraint systems maximizes protection of the child. Increasing reports of misuse is a call to those who manufacture these child passenger restraints to improve advertising and marketing to the correct age group, ease of installation, and mechanisms to prevent incorrect safety strap and harness placement. To ensure accurate and consistent use on every trip, car seat manufacturers must ensure that best practice recommendations for use as well as age, weight, and height be clearly specified on each child restraint. The authors support the United States Department of Transportation's new consumer program that will assist caregivers in identifying the child seat that will fit in their vehicle. In addition, due to the increase in premature graduation of children into belt-positioning booster seats noted as a result of legislation, promoting and marketing booster seat use for children less than 40 pounds should not be accepted. Child passenger safety technicians must continue to promote best practice recommendations for child passenger restraint use and encourage other community leaders to do the same.     

淮河流域一次梅雨锋暴雨的中尺度动力特征分析

针对2007年7月8日发生在苏皖淮河流域的暴雨,采用WRF中尺度数值模式模拟结果、FNL每日4次1°*1°再分析资料、6h地面实况观测降水资料和FY-2相当黑体亮温TBB资料对该次降水的发生、发展过程进行了分析研究。结果表明:(1)该次降水在有利的大气环流形势下,强降水发生在呈准东西向分布的梅雨锋上。位于蒙古国与我国华北—东北交界处上空的切断低压给淮河流域输入了冷空气。冷空气与西南低空急流带来的暖湿气流交汇,增强了大气斜压性;(2)正的非热成风涡度的发展促进了高层相对于低层的辐散减压,有利于垂直上升运动的发展;(3)低空强急流带所形成的动力、热力和水汽条件对暴雨落区位置产生了重要影响。     

Thoracic and lumbar spine responses in high-speed rear sled tests

Objective: This study analyzed thoracic and lumbar spine responses with in-position and out-of-position (OOP) seated dummies in 40.2 km/h (25 mph) rear sled tests with conventional and all-belts-to-seat (ABTS) seats. Occupant kinematics and spinal responses were determined with modern (≥2000 MY), older (<2000 MY), and ABTS seats.

Methods: The seats were fixed in a sled buck subjected to a 40.2 km/h (25 mph) rear sled test. The pulse was a 15 g double-peak acceleration with 150 ms duration. The 50th percentile Hybrid III was lap–shoulder belted in the FMVSS 208 design position or OOP, including leaning forward and leaning inboard and forward. There were 26 in-position tests with 11 <2000 MY, 8 ≥2000 MY, and 7 ABTS and 14 OOP tests with 6 conventional and 8 ABTS seats. The dummy was fully instrumented. This study addressed the thoracic and lumbar spine responses. Injury assessment reference values are not approved for the thoracic and lumbar spine. Conservative thresholds exist. The peak responses were normalized by a threshold to compare responses. High-speed video documented occupant kinematics.

Results: The extension moments were higher in the thoracic than lumbar spine in the in-position tests. For <2000 MY seats, the thoracic extension moment was 76.8 ± 14.6% of threshold and the lumbar extension moment was 50.5 ± 17.9%. For the ≥2000 MY seats, the thoracic extension moment was 54.2 ± 26.6% of threshold and the lumbar extension moment was 49.8 ± 27.7%. ABTS seats provided similar thoracic and lumbar responses. Modern seat designs lowered thoracic and lumbar responses. For example, the 1996 Taurus had ?1,696 N anterior lumbar shear force and ?205.2 Nm extension moment. There was ?1,184 N lumbar compression force and 1,512 N tension. In contrast, the 2015 F-150 had ?500 N shear force and ?49.7 Nm extension moment. There was ?839 N lumbar compression force and 535 N tension. On average, the 2015 F-150 had 40% lower lumbar spine responses than the 1996 Taurus. The OOP tests had similar peak lumbar responses; however, they occurred later due to the forward lean of the dummy.

Conclusions: The design and performance of seats have significantly changed over the past 20 years. Modern seats use a perimeter frame allowing the occupant to pocket into the seatback. Higher and more forward head restraints allow a stronger frame because the head, neck, and torso are more uniformly supported with the seat more upright in severe rear impacts. The overall effect has been a reduction in thoracic and lumbar loads and risks for injury.