Using LaModel to analyze coal bumps

Coal bumps have long been a safety hazard in coal mines, and even after decades of research, the exact mechanics that cause coal bumps are still not well understood. Therefore, coal bumps are still difficult to predict and control. The LaModel program has a long history of being used to effectively analyze displacements and stresses in coal mines, and with the recent addition of energy release and local mine stiffness calculations, the LaModel program now has greatly increased capabilities for evaluating coal bump potential. This paper presents three recent case histories where coal stress, pillar safety factor, energy release rate and local mine stiffness calculations in LaModel were used to evaluate the pillar plan and cut sequencing that were associated with a number of bumps. The first case history is a longwall mine where a simple stress analysis was used to help determine the limiting depth for safely mining in bump-prone ground. The second case history is a room-and-pillar retreat mine where the LaModel analysis is used to help optimize the pillar extraction sequencing in order to minimize the frequent pillar line bumps. The third case history is the Crandall Canyon mine where an initial bump and then a massive pillar collapse/bump which killed 6 miners is extensively back-analyzed. In these case histories, the calculation tools in LaModel are ultimately shown to be very effective for analyzing various aspects of the bump problem, and in the conclusions, a number of critical insights into the practical calculation of mine failure and stability developed as a result of this research are presented.     

环形起重设备的局部动力效应和抗震分析

对大型环形起重机设备进行抗震分析时,考虑了局部动力效应的影响及不同标高处系统加速度谱值的变化,推导了大型环形起重机设备在42.5 m标高处的地震作用及地震响应计算公式。编制了相应的计算程序,通过对实际设备的分析与计算,探讨了局部动力效应及加速度谱值变化的影响,这对工程设计具有一定的指导意义。     

UTN承载政企客户专线的解决方案研究

首先介绍了目前政企客户专线承载的主要技术并进行了对比,结合UTN网络的实际情况,提出了现网UTN承载政企客户专线的主要解决方案和相应的实施建议。针对智能专线业务承载提出了SDN-UTN部署建议,并对未来差异化业务承载方式进行了分析。     

Rapid heating of zirconia nanoparticle-powder compacts by infrared radiation heat transfer

Homogeneous rapid sintering of nanoparticle powder compacts of yttria-stabilized zirconia was achieved by the radiation heat transfer. Green bodies were prepared by cold isostatic pressing (CIP) at various pressures providing different porosity of samples before sintering. Pressure-less sintering was performed in air at a heating rate of 100 °C/min up to the 1500 °C/1 min. Scanning electron microscopy, mercury intrusion porosimetry, and Archimedes technique were used to characterize the microstructure and to determine the density of the green and sintered bodies. Contrary to expectations, our results reveal opposite dependence of the green- and sintered densities on the CIP pressure. Since the whole sintering process does not exceed 10 min, to propose what processes are responsible for observed results, our attention is focused on the radiation heat transfer from furnace heating elements into the ceramics. Our arguments are supported by numerical calculations of the electromagnetic field enhancement in/between particles.     

Integration of wavelet transform,Local Binary Patterns and moments for content-based image retrieval

The proliferation of large number of images has made it necessary to develop systems for indexing and organizing images for easy access. This has made Content-Based Image Retrieval (CBIR) an important area of research in Computer Vision. This paper proposes a combination of features in multiresolution analysis framework for image retrieval. In this work, the concept of multiresolution analysis has been exploited through the use of wavelet transform. This paper combines Local Binary Pattern (LBP) with Legendre Moments at multiple resolutions of wavelet decomposition of image. First, LBP codes of Discrete Wavelet Transform (DWT) coefficients of images are computed to extract texture feature from image. The Legendre Moments of these LBP codes are then computed to extract shape feature from texture feature for constructing feature vectors. These feature vectors are used to search and retrieve visually similar images from large database. The proposed method has been tested on five benchmark datasets, namely, Corel-1K, Olivia-2688, Corel-5K, Corel-10K, and GHIM-10K, and performance of the proposed method has been measured in terms of precision and recall. The experimental results demonstrate that the proposed method outperforms some of the other state-of-the-art methods in terms of precision and recall.     

Global–local interaction and its impact on cities

This introduction paper to the special issue of Journal of Housing and the Built Environment explores the interrelations among ‘globalization, urban systems, and local development’ by focusing on global-local interactions and their impacts on cities. After tackling the idea that globalization is about the spread of capitalism and capitalist principles throughout the world, the paper introduces the questions that each article intends to answer. The issues addressed by these questions were grouped under four headings: global versus local forces and urban change; urban systems within the global network of cities; globalization and property markets; and governance of globalizing cities.     

代建制在政府投资项目中的应用研究

我国近年已出台一系列政策法规,支持在政府投资项目中推行代建制,并在各地因地制宜进行了许多有益尝试,但同时也暴露出政策、技术等方面存在的问题,本文主要针对推行中出现的问题进行分析和研究。     

人工与自然的科学结合——体验巴塞罗那植物园

通过对巴塞罗那植物园规划理念、植物展示技术与手段及科学内涵的总结与分析,探讨当代富有特色的植物园景观规划方法,指出植物园的特色对其可持续发展的重要意义。     

论公共工程的政府采购行为

随着我国的加入世贸组织，全球经济一体化的要求使得我国公共工程纳入政府采购的对象成为必然。本文从工程项目的政府采购行为的特点入手，分析了这一必要性，并从政府的角度提出了一些对策及措施，对今后我国加入WTO的政府采购市场的开放无疑有着一定的积极意义。     

“城市经营”本质是对公共物品和公共服务的管理

对“城市经营”的源起、城市经营的内容和特征进行了阐述 ,分析了目前有关“城市经营”理解上的几个误区 ,并归纳了“城市经营”的定义。