急倾斜厚大矿体采矿方法的选择研究

云南怒江泸水外岩房锡钨矿在生产中对于急倾斜厚大矿体,计划采用分段凿岩阶段出矿分段空场采矿法进行开采。运用FLAC~(3D)计算机数值模拟技术对该矿山开采过程中采场顶底板,间柱的应力以及塑性区等特征的变化进行计算分析。结果表明:随着回采工作的结束,采场顶底板,间柱将出现明显的压剪、拉和拉剪等多种破坏,若采用上述空场类采矿方法将对矿山安全生产造成较大安全隐患。结合矿山实际情况,重新设计采用有底柱分段崩落法进行回采,为矿山安全生产提供了理论依据和技术支持。     

急倾斜矿体持续开采对空区上覆岩层的影响

开采扰动下采空区上覆岩层将产生位移和应力的重新分布。为研究云南某急倾斜铁矿在持续开采下空区上覆岩层移动和破坏情况,根据实验室试验得到的矿山岩体力学参数,建立了矿山有限元模型。对矿体的开采进行了模拟,得到该矿体逐层开挖后上覆岩层最大主应力和地表下沉值的分布图,综合分析急倾斜矿体持续开挖对采空区上覆岩层产生的影响。     

张双楼煤矿底板采动效应应力解析与数值模拟对比研究

为了评价张双楼煤矿9煤的底板突水,根据-350m和-500m两个水平的工作面的煤层底板地质特征,运用快速拉格朗日法对底板的采动效应进行了数值模拟,分析了采动过程中底板岩体应力场、塑性区的分布,通过建立采场底板破坏深度应力解析模型求得底板破坏深度值,认为底板破坏深度值介于两种方法得出值之间更为合理,研究结果为底板水害防治提供了理论依据。     

浅谈反底拱锚注支护技术的成功应用

<正>戚家坡煤矿生产能力1.4Mt/a,采用斜井单水平上下山开拓方式,开采深度300～500m。井下大部分开拓巷道布置在侏罗纪高应力软岩中,采用锚网(索)、喷浆支护,从支护效果上来看,对顶、帮控制总体上比较好,但部分巷道由于底板水及其它复杂因素影响,在底板底鼓控制上效果还不理想,巷道出现不同程度的底鼓。     

建筑物下条带开采地表移动变形预计分析

为了提高煤炭资源的回收率,延长矿井服务年限,解决采掘接替困难等问题;综合分析该矿采用采条带开采回收建筑物下的保护煤柱。条带开采后,采用概率积分法预测地表移动变形规律,并结合数值模拟软件FLAC3D进行数值分析,获得该矿区条件下走向条带开采时地表移动变化规律。研究结果表明:条带开采后保护建筑物范围地表最大下沉量为309 mm,最大水平变形为±0.253mm/m;建筑物受损程度小于Ⅰ级破坏范围,产生较小影响,可以保证地表建筑(构筑)物的安全实用。     

近距离上部煤层采空底板煤岩体中应力变化规律

摘要：近距离煤层上部煤层开采导致上覆岩层发生卸压运动，并且出现变形，煤层底板岩层也出现一定的卸压变形，采场围岩应力得到重新分布，形成了高应力区和低应力区。因此分析煤岩体中应力场分布变化规律，会对作面的布置和支护方式的选择都将产生较大帮助。     

图拉尔根铜镍矿采场结构参数数值模拟分析

以图拉尔根铜镍矿试验采场为研究对象，在对现场资料进行了全面收集整理的基础上，通过矿岩物理力学性质试验分析、数值模拟等方法对几种参数的试验采场在回采过程中的稳定性进行分析。对回采过程中试验采场的应力发展规律及回采过程与采场稳定性关系进行了研究。重点探讨了回采顺序对试验采场矿柱的稳定性的影响。在回采过程中，要采取应力、应变、位移等多种观测手段和方法，对上下盘围岩、矿柱、顶柱进行监测，掌握矿岩应力变化规律，做出安全预报。     

采动影响范围高速公路变形观测

綦万高速公路在万盛平山穿越南桐煤矿北翼地表,按照井下开采变形预计,会影响公路的质量。文章对受煤矿采动影响范围内的地表移动变形情况进行观测,通过对观测站数据的处理、分析,及时掌握井下开采对高速公路的变形影响情况,指导损害维修和安全生产。     

浅谈采煤工作面上覆岩层移动规律

煤层采出后,采空区周围原有的应力平衡状态受到破坏,引起应力的重新分布,从而引起岩层的变形,破坏与移动,并由下向上发展至地表引起地表的移动,在此主要分析了采煤工作面上覆岩层移动规律。     

回采巷道变形分析及支护选择

煤矿回采巷道受矿山应力及采动影响;顶底板岩性特性;地质构造应力多方面的共同作用,在回采工作面尚未回采完毕时,巷道变形破坏严重,断面缩小不能满足生产要求,分析回采巷道的变形和破坏特点、原因,选择合理的支护参数和施工工艺,提高工程质量,加强生产管理,探索不同地质条件下支护手段,满足矿井安全生产要求.     

Development in Information and Communications Technology (ICT) Statistics at the Australian Bureau of Statistics

This paper outlines the ICT statistical developments that the ABS has undertaken over recent years. These developments have been on both the supply side (ICT industry) and the demand side (use of IT by sector). The content of ABS ICT surveys has changed significantly over the last few years and are expected to develop further in line with industry changes and emerging policy needs.
Recent developments in household collections have been the inclusion of IT use questions in the 2001 Census of Population and Housing and in various ABS social surveys such as Children's Participation in Culture and Leisure Activities. Annual business IT use surveys are now conducted and include topics such as Internet commerce and IT security. Biennial ICT industry surveys are conducted to provide data on ICT production, imports and exports, ICT industry employment, performance and structure information. An Internet activity survey is run every six months and provides regional Internet access details and infrastructure details on Internet service providers.
A major development for 2002–03 will be the compilation of an ICT satellite account. ABS intends to produce an ICT Information Development Plan to guide its future statistical development work in the ICT field.     

Incumplimiento del salario mínimo en Europa central y oriental

En este estudio se analiza el incumplimiento del salario mínimo durante el periodo 2003–2012 en diez países de Europa central y oriental con salario mínimo obligatorio nacional. A partir de los datos de EU‐SILC y la metodología propuesta por Bhorat, Kanbur y Mayet (2013), se cuantifica la incidencia y magnitud del incumplimiento. Se realizan análisis de regresión sobre determinantes individuales, laborales y macroeconómicos. Aunque la incidencia permanece relativamente baja, los trabajadores a los que se dirigen las políticas de salario mínimo parecen los más expuestos a su incumplimiento. Con el tiempo, una mayor incidencia se asocia a una razón más alta entre salario mínimo y salario medio.     

Value at Risk in the Suburbs: Eminent Domain and the Geographical Politics of the US Foreclosure Crisis

Several US counties and local governments have recently considered a novel solution to the foreclosure crisis. They plan to use eminent domain to compel the owners of mortgage debt—and specifically of private‐label mortgage‐backed securities—to sell the debt to the government at a price reflecting the loan's market value. The government would then restructure the debt and resell it to new investors. The plans are striking because—in contrast to both development‐driven eminent domain and the federal subprime bank bailout—they would force investors to assume asset devaluation and increased long‐term risk. Notably, the plans have emerged as an instance of financialization‐focused politics in suburbs and suburban cities of color, specifically majority‐black and ‐Latino/a suburbs. Local support for the plans, we argue, is rooted in the long‐term disinvestment of these ‘suburbs of exception', which became targets of subprime lending and eventually sites where the ‘financial exception' has been localized. But these demographic shifts, fragmentation and fiscal pressures have at the same time created a suburban political terrain in which the plans have gained their strongest political support.     

Towards a Theory of Serendipity: A Systematic Review and Conceptualization

Serendipity – the notion of making surprising and valuable discoveries – plays a major role in the success of individuals and organizations alike. Previous research has established the importance of serendipity and identified important individual- and organizational-level antecedents. However, the literature has been dispersed and the boundaries of the concept have been blurry, leading to a lack of conceptual clarity and structure, and thus limiting validity and managerial actionability. Based on a systematic literature review, I synthesize existing management-related research on serendipity and explicate the emergence and composition of serendipity in the organizational context. I first identify three necessary conditions that differentiate serendipity from related concepts such as luck or targeted innovation: agency, surprise, and value. Then, I draw from the literature on sensemaking, event-based theorizing, and quantum-based approaches to management to conceptualize the process of cultivating serendipity in the organizational context as a process of enabling potentiality and materialization, and develop a multi-level theory of (cultivating) serendipity. This conceptualization contributes to our collective understanding of how, why, and when (i.e., under what conditions) organizations can leverage the value in the unexpected, which opens up fruitful avenues for further research.     

Accountability of NGOs in Bangladesh A critical overview

NGOs in Bangladesh have been recognized as effective change agents in the socio-economic arena throughout the world. Their contributions in micro credit, non-formal education and primary health care are widely known. NGOs play a significant role in society. NGO accountability, as a result, has become a critical issue. NGO accountability in Bangladesh has been examined here in relation to patrons, clients and themselves. Of the three relationships only accountability to patrons is in a near satisfactory state. Accountability to clients is handicapped by lack of opportunities of beneficiaries to participate meaningfully in NGO policy making. Accountability to themselves is adversely affected due to the adherence to a strictly hierarchical system and the influence of founding and charismatic NGO leaders.     

Towards an Asian model of human resource management? A comparative analysis of China,Japan and South Korea

There has been much discussion regarding the possible decline and weakening of national systems of human resource management (HRM). Yet, culture and institutions are often cited as the major stumbling blocks to this outcome. Such constraints may dissipate in the analysis, particularly if ‘regional clusters’ are considered where geographic and cultural closeness and ‘openness’ to similar economic pressures exist. In such cases, it might be postulated that convergence in HRM will occur. We argue that China, Japan and South Korea represent such a cluster. This article examines these countries, to see if a degree of convergence is taking place and if it is towards an identifiable ‘Asian’ model of HRM. A model of change is presented that distinguishes between levels of occurrence and acceptance. Details of the development and practice of HRM in each country are then set out. The article ends with a discussion and implications section and a brief conclusion.     

Cultural Economy Planning in Creative Cities: Discourse and Practice

While a growing body of research analyses the functional mechanisms of the cultural or creative economy, there has been little attention devoted to understanding how local governments translate this work into policy. Moreover, research in this vein focuses predominately on Richard Florida's creative class thesis rather than considering the wider body of work that may influence policy. This article seeks to develop a deeper understanding of how municipalities conceptualize and plan for the cultural economy through the lens of two cities held up as model ‘creative cities’ — Austin, Texas and Toronto, Ontario. The work pays particular attention to how the cities adopt and adapt leading theories, strategies and discourses of the cultural economy. While policy documents indicate that the cities embrace the creative city model, in practice agencies tend to adapt conventional economic development strategies for cultural economy activity and appropriate the language of the creative city for multiple purposes.     

Input/output ranges and performance: an examination of US machine tool producers

Despite the establishment of high-tech multinational enterprises (MNEs) in Ireland since the late 1950s, the country did not succeed in closing the technological gap with most of its EU counterparts. The weak National System of Innovation (NSI), and in particular low business and government R&D levels, combined with a lack of research and technology linkages between MNEs and indigenous firms, explain these poor results. However, the Shannon region in the West of the country presents some specific institutional characteristics that could theoretically make the region a strong technological enclave. The various actors in the region - i.e. the administrative, financial, political and research institutions, as well as the business organizations - have indeed infused a new type of economic development. After a brief review of the available concepts and models articulated around these actors and their interrelationships, the paper analyses whether the Shannon region, taken as an illustrative example, mirrors a specific economic and technological localized setting. The study is based on a survey of indigenous and foreign firms.     

Sixty years of discrimination and diversity research in human resource management: A review with suggestions for future research directions

This article reviews discrimination and diversity research published in Human Resource Management (HRM) over the past 60 years. While discrimination and diversity are very different constructs, it is often informative to study them together, because when people recognize each other's diversity, this can result in bias, stereotyping, and discrimination. We conducted bibliographic searches for terms related to discrimination and diversity as well as a manual search through every title and abstract published in HRM over the last 60 years to assess article relevance. The search resulted in 135 research articles with 136 unique studies (i.e., samples) which are reviewed in this article. Sex and race are the demographics that have been examined the most in HRM, while religion has been examined the least. Moreover, the number of studies examining lesbian, gay, bisexual, transgender, and queer (LGBTQ) employees in the workplace in HRM has grown quickly within the past 10 years, culminating in a recent meta‐analysis. Our review looks at some of the earliest research published, the most recent research published, and the overall trends we identified in the research over the years for both discrimination and diversity articles. We then make future research suggestions and recommendations to advance the study of discrimination and diversity in the coming years.     

Multinomial distributions applied to random sampling of particulate materials

When sampling a batch consisting of particulate material, the distribution of a sample estimator can be characterized using knowledge about the sample drawing process. With Bernoulli sampling, the number of particles in the sample is binomially distributed. Because this is rarely realized in practice, we propose a sampling design in which the possible samples have a nearly equal mass. Expected values and variances of the sample estimator are calculated. It is shown that the sample estimator becomes identical to the Horvitz–Thompson estimator in the case of a large batch-to-sample mass ratio and a large sample mass. Simulations and experiments were performed to test the theory. Simulations confirm that the round-off error due to the discrete nature of particles is negligible for large sample sizes. Sampling experiments were carried out with a mixture of PolyPropylene (PP) and PolyTetraFluorEthylene (PTFE) spheres suspended in a viscous medium. The measured and theoretical variations are in good agreement.