秦皇岛港贮煤场的生态恢复与煤尘防治

分析了秦皇岛港后煤场边界整体大气环境现在能够达到的质量水平，指出在现有基础上改善后煤场边界大气环境水平的有效途径是建设生态防风林带，给出了建设防风林带所需详细理论测算资料。     

四川盆地大气边界层风速廓线探讨

本文总结有关四川盆地大气边界层风场特征研究成果,对其风速特征、边界层风速廓线进行探讨。结果表明,四川盆地具有风速小,且风速垂直梯度亦小的特征;风速随高度分布基本遵循经验爱克曼螺线,这一经验公式可在四川盆地内推广应用。     

利用微生物快速挂膜技术治理糖果废水的研究

利用微生物快速挂膜技术对糖果废水治理进行研究,结果表明:该技术对废水中CODCr及BOD5的去除有显著的效果。当废水的pH值为6～8、水温为25～35℃、CODCr及BOD5分别在3000～9000mg/L和1000～3000mg/L时,CODCr及BOD5的去除率分别大于92%和99%,为糖果废水治理达标排放奠定了基础。     

高速冲裁的卸料形式

为保证多工位级进模在高速冲裁中连续进行 ,卸料装置不但起冲前压料 ,冲后卸料的作用 ,还对凸模起精密导向和有效保护作用 ,介绍了 4种能满足多工位级进模高速冲裁的卸料装置。     

Measures of speeding from a GPS-based travel behavior survey

Objective: Lacking information about actual driving speed on most roads in the Minneapolis–St. Paul region, we determine car speeds using observations from a Global Positioning System (GPS)-based travel survey. Speed of travel determines the likelihood and consequences of collisions. We identify the road segments where speeding occurs. This article then analyzes the relationship between link length, traveler characteristics, and speeding using GPS data collected from 152 individuals over a 7-day period as part of the Minneapolis–St. Paul Travel Behavior Inventory.

Methods: To investigate the relationship, we employed an algorithm and process to accurately match the GPS data with geographic information system (GIS) databases. Comparing actual travel speed from GPS data with posted speed limits, we measure where and when speeding occurs and by whom. We posit that link length and demographics shape the decision to speed.

Results: Speeding is widespread under both high speed limits (e.g., 60?mph [97?km/h]) and low speed limits (less than 25?mph [40?km/h]); in contrast, speeding is less common at 30–35?mph (48–56?km/h). The results suggest that driving patterns depend on the road type. We also find that when there are many intersections, the average link speed (and speeding) drops. Long links are conducive to speeding. Younger drivers and more educated drivers also speed more, and speeding occurs more often in the evening.

Conclusions: Road design and link length (or its converse, frequency of intersections) affect the likelihood of speeding. Use of increasingly available GPS data allows more systematic empirical analysis of designs and topologies that are conducive to road safety.     

凝冰路面弯道路段停车视距计算方法

考虑到我国公路路线设计规范中停车视距计算未涉及弯道参数及路面凝冰引起的路面摩阻系数降低等严重危害车辆行驶安全的因素,以AASHTO模型为基础,通过分析弯道路段车辆行驶时的受力、路面摩阻系数、超高、圆曲线半径等因素推导了凝冰路面弯道路段停车视距计算模型,得出了最不利情况下凝冰路面弯道路段停车视距参考值。当路面发生凝冰现象时,若车辆以交通安全法规规定的冰雪路面最高车速30 km/h行驶,通过对比该行驶速度下凝冰路面弯道路段停车视距与我国规范规定的停车视距可知,没有发挥道路的最大通行能力。以现有道路设计采用的停车视距反算出在役路面发生凝冰现象时的安全行车控制速度,为凝冰路面弯道路段车辆安全行驶控制提供参考。     

坚硬顶板综采工作面推进速度对矿压规律影响研究

以顾桥煤矿坚硬顶板综采工作面工程地质条件为背景,运用理论分析、数值模拟和现场实测手段,分析了开采速度对工作面覆岩运动、围岩破坏、应力分布和液压支架承载特性的影响。研究结果表明:1个周期来压内工作面落煤引起的岩梁刚性回转下沉量是一定的,工作面作业循环时间引起的岩梁蠕变下沉量与岩梁刚性回转下沉量呈正比,加快工作面推进速度仅减少围岩体蠕变引起的岩梁下沉部分。工作面开采速度增加,覆岩塑性区发育范围减小,煤壁应力集中位置变浅、应力集中系数变小。工作面快速推进时,液压支架承载多为2次増阻和3次増阻,支架工作阻力较小;缓慢推进时,液压支架承载多为1次急增阻,载荷近似呈线性增长,支架工作阻力较大。     

新风速分布模型在抗风防灾风险分析中的应用

作者提出一种新风速分布模型，分析评估各种概率的风速，并推求相应的风压，为抗风防灾风险性分析提供合理依据。     

Fast flame speeds and rates of pressure rise in the initial period of gas explosions in large L/D cylindrical enclosures

Flame speeds and rates of pressure rise for gaseous explosions in a 76 mm diameter closed cylindrical vessel of large length to diameter ratio (L/D = 21.6), were quantitatively investigated. Methane, propane, ethylene and hydrogen mixtures with air were studied across their respective flammability ranges. Ignition was affected at one end of the vessel. Very fast flame speeds corresponding to high rates of pressure rise were measured in the initial 5–10% of the total explosion time. During this period 20–35% of the maximum explosion pressure was produced, and over half of the flame propagation distance was completed. Previous work has concentrated on the later stages of this type of explosion; the development of tulip flames, pressure wave effects and transition to turbulence. The initial fast phase is very important and should dominate considerations in pressure relief vent design for vessels of large L/D.     

含油污泥离心脱水中离心机参数的选择

通过对含油污泥离心脱水的批量处理和连续处理的研究，取得了含油污泥水固两相离心分离的满意效果。实验表明，适宜的操作参数可提高离心脱水效果。对LWD-430卧式螺旋离心机，当离心速度在1200～1400r／min之间，处理量在1，3m^3／h之间，差转速（转鼓与螺旋推料器的转速差）为20r／min时，离心液体积和COD均达到最佳状况。离心速度过高，会使絮体中的油离解出来，从而使离心液COD增加。差转速增加能明显改善“三泥”的离心脱水效果。