The RUB Tunneling Device – A newly developed test method to analyze and determine the wear of excavation tools in soils

The efficiency of a tunneling project is mainly associated with the abrasivity of the acting soil and the wear resistance of the cutting tools. Heavy wear can dull the cutting tool, which negatively affects the penetration rate and therefore the efficiency of a tunneling process. Completely worn tools with a short service life have to be replaced by newer ones. This circumstance results in unplanned machine shutdowns and higher maintenance costs. It is thus of high economic as well as technical interest to obtain a deeper understanding of soil/cutting tool interactions during tunneling. To meet this challenge, a large number of different testing devices to estimate the abrasivity of soils have been developed within the last two decades. An innovative and promising experimental setup is presented in this work. A horizontal implementation offers the possibility of simulating a tunneling process as well as the tribological system of a TBM tool. The interactions between all system components can be mapped and analyzed in detail. This method offers a unique setup, which allows wear prediction of TBM tools in a homogeneous soil with project-specific parameters (soil composition/condition, soil mechanics, tool material and machine/tunneling data).     

桥式偏心精细分注工艺及测调技术研究与应用

长庆油田注水井具有＂定向井、小水量＂的特点和难点,对分注工艺的可靠性和实用性提出了更高的要求。随着油田开发时间的不断深入,常规分注工艺存在分注有效期短、测试投捞成功率低、测试误差大等问题。本文通过桥式偏心分注工艺的研究与应用,完善配套了测调技术,初步满足了定向井小水量注水的技术需要,为精细化注水提供了新的技术借鉴。     

An investigation of microstructure evolution in cement paste through setting using ultrasonic and rheological measurements

The response of hydrating cement paste through setting are monitored using rheological measurements and ultrasonic reflection measurements. Increases in the elastic modulus and yield stress of cement paste with time are obtained from the rheological measurements. Ultrasonic measurements are performed using horizontally polarized shear waves (SH) reflected off of the hydrating cement paste. Changes in the ultrasonic signal through setting are related with changes in the porosity and stiffness of an equivalent water-filled poroelastic material, which provides identical acoustic impedance. The measured changes in the shear modulus obtained from ultrasonic measurement are shown to correlate well with increase in elastic modulus obtained from rheological measurements. The increase in the shear modulus of the porous material obtained from the ultrasonic measurements is shown to correspond well with the observed increase in the yield stress of the cement paste. By combining the information from rheological and ultrasonic measurements, it is found that even in the fluid stage there is sufficient structural integrity in the arrangement of cement grains to support low-amplitude shear stress and the evolution of a continuously connected network of cement particles within the paste is coincident with a rapid increase in the shear modulus of the porous skeleton.     

智能变电站合并单元现场测试技术研究

合并单元是智能变电站数字化信息传输的基础和保证,肩负着一次设备参量和间隔层设备的正确信息通信功能。目前电力行业标准只提出了合并单元应具备的性能指标和要求,并未对合并单元性能指标具体的测试方法给予说明。在综合分析合并单元性能指标的基础上,提出了合并单元现场测试的关键性能指标,并制定了相应的测试方案,通过实际工程的测试结果进行了验证,证明了该测试方案的有效性和准确性。     

风力发电机低电压穿越两种测试方法对比分析

对两种不同的风力发电机低电压穿越测试方法中变流器的冲击电流进行了对比研究,由于风机出口变压器的Δ/Y变换,在中压侧和在低压侧设置电压跌落点对风机的实际影响不同,通过理论分析和实际试验,得知在中压侧测试方法不能模拟高压侧电网两相电压跌落,低压侧测试方法能够较全面模拟高压侧电网电压跌落情况;低压侧测试两相电压跌落时会产生高于三相和单相电压跌落时的不平衡电流,对风机变流器耐流性能要求更高。     

\"死棉\"的检测

阐述棉织物、棉纱中“死棉”产生的原因及对产品的影响,介绍一种简便的“死棉”染色检测方法,可以预防因“死棉”而造成的损失,以此提高产品质量。     

关于图象分割性能评估的评述

概述了图象分割性能评估发的发展,总结了分割性能评估的基本理论框架：确定图象分割性能评估指标,构造评估测试图象集,评估模型与实验分析,以及分割性能评估的常用方法：统计法,基于ＡＩ的方法和混合法。对评估模型的设计作一些尝试性的探讨。     

基于NHPP类模型的Web软件可靠性分析

结合Web软件运行的实际情况,提出一种基于BurrX测试工作量函数(TEF)的非齐次泊松过程类软件可靠性增长模型(SRGM),并将其应用到Web软件可靠性分析中。TEF能直接体现Web软件工作量与日历时间之间的关系,解决Web软件因工作量高度不均衡导致的问题。实验结果表明,与G-O模型相比,SRGM具有较好的Web软件可靠性评估效果,能较准确地描述Web软件运行的失效过程。     

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由于缺乏精确测量临界凝析油饱和度测试技术,我国凝析气藏油气相对渗透率均使用常规油气进行测试,采用真实平衡凝析油气体系对凝析气藏相对渗透率曲线进行岩心驱替测试还无先例。文章选用牙哈凝析气藏真实岩样进行了两组驱替实验,第一组是向岩样注入煤油-氮气采用非稳态法,第二组是注入平衡凝析油气采用稳态法。此外,研究了两种测试系统下油气相对渗透率对凝析气藏开发动态的影响,得出以下结论：①凝析油气系统的相对渗透率曲线整体向右移动,气相对渗透率下降非常快,油气相对渗透率高于煤油-氮气系统的油气相对渗透率;②凝析油气系统的临界凝析油饱和度比煤油—氮气系统的凝析油临界饱和度约低20%;③煤油-氮气系统预测的气体产能、气油比、凝析油气采收率比凝析油气系统预测的结果低得多,但气藏压力下降较慢;④凝析油气系统与煤油-氮气系统近井地带析出凝析油饱和度分布存在显著差别。