大型土石方爆破工程的钻孔统计分析

为了找出炸药单耗和延米爆破方量的实际值与预算值之间的差别原因,对我国北方一大型土石方爆破工程的钻孔按施工进度进行了统计。并对孔深与延米爆破方量的关系进行了分析。研究发现小于5m深的炮孔数量的比例较大,是降低综合延米爆破方量的一大主要因素。因此得出,缓斜坡的台阶爆破工程中,在孔网参数和台阶高度一定的条件下,通过优化组合,减少浅孔的数量,可以有效地提高项目综合延米爆破方量,从而为缓斜坡台阶爆破降低项目成本指明了方向。     

液压动载轴承试验台的设计与分析

本文给出了液压动载员承试验台的设计方法，并应用于YZ-1试验台的开发，这类试验台可模拟可变脉动载荷滑动轴承的工作状况，适用于相应的工作条件下轴承工作特性和可靠性的研究。     

Bench-scale assessment of combustion toxicity—A critical analysis of current protocols

The toxicity of fire effluents is not a material property but a function of both the material and the fire environment. To be meaningful, it is essential that toxicity results should relate to the end-use fire situation. This paper reviews current fire effluent toxicity tests, their relevance to fire, and the ways of assessing and applying their results to reduce fire hazards. There are a large number of different methods for determination of the toxic potency of fire effluents from materials or products. These different methods yield apparently inconsistent data because they represent different fire scenarios; measure product yields either as a function of material flammability or independent of it; base the toxicity assessment on the concentrations of different species; or use animal exposure to generate an overall estimate of toxic potency without knowledge of the relative contributions of the chemical species.     

Experimental Investigation of Friction Effects Enhanced by Tool Geometry and Forming Method on Plane Strain Sheet Metal Forming

An experimental study on friction was conducted on aluminum and steel sheets for automotive applications. Cold-rolled mild and high strength steel, electrogalvanized steel and aluminum grades Al6111T4 and Al 2008T4 were tested under various levels of bending under tension, plain strain forming mode. The friction and forming severity of the tests were promoted through the use of a set of tools of decreasing radii sizes. The test methods includes flat platens, draw bead simulation, 90-degree bending under tension and tools with rectangular geometry. A systematic pattern of frictional behavior, common to all tests was observed. An initial spike, associated to static friction, was followed by a more stable plateau. The effects of the static friction on the forward flow were studied in function of parameters such as the testing method, the tool radii, the testing speed, etc. The results showed that the static friction may be increased by the forming method, and its effects on the forward flow varied significantly depending on the material and lubrication. Based on the results of this study, general forming practices for these materials were recommended.     

南芬露天铁矿火钻扩孔试验

针对南芬露天采场生产爆破遗留根底问题，对采场3种矿石进行了实验室实验和手持式火钻扩孔现场工业试验。试验表明，在3种矿石中采用火钻护孔爆破克服台阶根底是一种有效途径。     

Benchmarking of Construction Productivity

Construction productivity has been a cause of great concern in both the construction industry and academia. Even though many companies have developed their own productivity tracking systems based on their experiences and accounting systems, none have been successful in establishing common definitions and developing a survey tool that collects standard productivity data at the appropriate levels. This research was initiated to establish a common set of construction productivity metrics and their corresponding definitions. As a result of this research effort, the Construction Productivity Metrics System (CPMS), which contain a list of direct and indirect accounts and 56 data elements grouped into seven major categories, was developed. The Construction Productivity Metrics System is a standard construction productivity data collection tool and provides a framework to report industry norms to benchmark construction productivity. Input from 73 industry experts was used in determining the 56 measuring elements and their corresponding definitions. Preliminary findings from initial sample of 16 industrial projects indicate that the productivity metrics can be produced and should be meaningful for construction productivity benchmarking. Because of the small sample size, more than general preliminary conclusion would be inappropriate. Based on the analyses, the developed CPMS is believed to be a reasonable productivity data collection tool and when sufficient data are available should be capable of producing reasonable industry benchmarks.     

关于BMMC爆破数学模型的一个修正

本文在考虑了岩石断裂面的分形特征之后,提出了新的爆破决度尺寸ｄ＿ｉ的计算方法,对ＢＭＭＣ模型作了修正。计算表明：修正后的模型克服了原模型倾向大决湍的缺点,与实际符合得更好。     

中深孔台阶爆破在城市中的应用

作者结合多年在城市进行控制爆破的经验,对城市复杂环境下的中深孔爆破的设计与安全施工进行了探讨和总结。     

台阶式中深孔延时加强松动爆破

通过山体爆破工程设计实例,介绍了台阶式布孔方法以及中深孔延时加强松动爆破施工的设计思路。提出了孔排距、炸药单耗、装药结构、起爆方式等爆破参数的确定方法。通过该工程中采用的孔内外联合延时非电起爆网路,达到了单孔单响的目的。测振数据表明,本次爆破施工有效地控制了爆破振动和飞石,取得了比较满意的爆破效果,对类似工程有一定的参考价值。     

永磁无刷直流电机驱动系统及其应用

介绍了无刷无槽永磁直流电机的结构和特点以及在高速台式离心机中的应用实例。对该应用中的刹车功能进行了重点论述。