我国煤中微量元素的赋存及开发利用

煤中微量元素的赋存规律和综合利用工艺的研究和开发，对于资源的合理利用具有重要意义。在综合国内煤中微量元素研究文献的基础上，分析了煤中微量元素的来源可分为原生、次生和后生，赋存状态主要与有机质的吸附和络合作用有关；开发利用的现状较为落后，表现为研究区域少、研究手段和技术水平差。指出，必须深入对煤中微量元素的赋存规律和综合利用工艺进行深入研究，合理利用资源，使矿区实现可持续发展。     

National minerals policies and stakeholder participation for broad-based development in the southern African development community (SADC)

This paper explains how the well-accepted concept of improved stakeholder participation during mineral policy development leads to a national mineral policy that accommodates the diverging views and interests that allows wide acceptance of decisions, enhancing the success of implementation and, ultimately, national benefits. This process is based on lessons learnt during the South African experience and has been successfully applied in the development of the Namibian and Malawian national minerals policies. An effective policy in the SADC will engineer the delicate balance between poverty reduction and an internationally competitive minerals sector. This balance enhances the possibility of long-term economic growth and development in the SADC region. The overriding advantage of this strategy is that it generates ‘home-grown’ policy instruments and implementation of mineral law with which stakeholders can identify. This process presents a new challenge to traditional policy formulation strategies in emerging economies and the bottom-up approach, linked to wide political support, allows the potential realisation of national objectives.     

CITY OF TUCSON WASTE WATER EFFLUENT DELIVERY FACILITY1

ABSTRACT: The Tucson area is totally dependent on ground water, which is in increasingly short supply due to excessive overdrafts. Tucson area waste water treatment plants discharge material quantities of secondary effluent downstream, which is lost to evapotranspiration and recharge of the ground water basin. The city and the four large mining companies who share the common Santa Cruz basin ground water, recognized the common water supply problem and agreed to fund a feasibility study for mining process use of the effluent to partly alleviate the overdraft of ground water. The study analyzed the projected waste water effluent resources, potential mining company demand for waste water effluent and possible interface of an effluent delivery facility with the proposed Central Arizona Project. The effluent resources were analyzed with respect to potential demand. An optimum alignment was selected. An optimum system was detailed through design schematics, amortized cost and finance requirements, and an implementation schedule. It was concluded that a waste water effluent delivery facility could be implemented which would utilize reclaimed effluent in quantities approximating 35 percent of basin overdraft and which would provide revenue for full cost recovery over a 20 year operation period. The mining companies are studying the internal economic impacts of the project.     

TOXIC METALS IN SURFACE WATERS FROM COAL ASH1

ABSTRACT: The concentration of 10 [titanium (Ti), manganese (Mn), copper (Cu), chromium (CR), zinc (Zn), arsenic (As), selenium (Se), cobalt (Co), cadmium (Cd), and mercury (Hg)] toxic elements were measured in the water, benthic sediment, plants, invertebrates, and vertebrates of an ash basin and its drainage system at a coal-fired power plant of the Savannah River Project, Aiken, S.C., over a period of two years. During 12 months of this period the basin was essentially filled and little settling of ash occurred. In the remaining 12 months, dredging had been completed, adequate settling occurred and most of the effluent turbidity was removed. All elements were more concentrated in sediment and biota than in water, and five (Mn, Cu, As, Zn, and Se) were biomagnified by at least one biotic component as compared to concentration in benthic sediment. Plants had high accumulations of Ti, Mn, As, and Hg; invertebrates had high accumulations of Co, Hg, Cu, Cr, Cd, and As; and vertebrates greatly biomagnified Se and Zn. The streamlined biotic community of the system accomplished major removal of Mn, Zn, As, Se, and Cd from the effluent. The magnitude of bioaccumulation of Ti, Mn, Zn, As, Se, Cd, and Hg was increased during the period of adequate settling in the basin.     

甲烷-煤尘爆炸波与障碍物相互作用的数值研究

为了探讨煤矿瓦斯和煤尘爆炸的物理机制 ,基于对甲烷和煤尘爆炸传播的理论分析 ,采用数值模拟方法研究障碍物对甲烷和煤尘爆炸传播的影响 ;为了更系统地考虑颗粒相各种输运特性、相间滑移和耦合 ,采用双流体模型建立了数学模型 ,该模型的出发点是把颗粒群和气体都作为连续介质 ,两者相互渗透充满整个空间形成没有间隙的“流体”———拟流体 ,在欧拉坐标系下考虑气 -固两相流动 ,气相和颗粒相的计算网格统一 ,易于处理。数值方法采用LU分解和迎风TVD格式分别处理对流项的隐式和显式部分 ,扩散项采用中心差分 ;同时研究了不同形状的障碍物对流场的影响 ,计算结果与实验吻合较好     

谈"动态对等"的缺陷

美国著名翻译理论家Nida提出的"动态对等"原则是对翻译理论界的一大贡献.笔者在承认这个原则的同时,从它概念的几个关键词入手,指出这个概念中几个值得商榷的地方,认为它的理论基础不牢靠,并分析了它所忽视的翻译所涉及的几个要素,由此表明,翻译这种涉及到许多因素的复杂活动不能依靠一种理论来指导.     

Information in the Animate and Inanimate Worlds

Closed systems are governed by the second law of thermodynamics and cannot spontaneously become more ordered. In open physical systems exposed to external energy flows, additional macroscopic degrees of freedom (memory cells) emerge, their number increasing with an increase in the flow and orderliness of the external energy. Biological systems are characterized by molecular degrees of freedom, the density of which is more than twenty orders of magnitude higher than that of macroscopic degrees of freedom in any open physical system exposed to the same external energy flow. This indicates that the self-organization of physical systems in external energy flows and the self-organization and evolution of living systems are fundamentally different. Thus, although life is an open system, the energy (food) flows that it consumes and all other external factors affecting life are so poorly ordered, compared to life itself, that they cannot increase the degree of order in the latter. Therefore, living systems obey an analogue of the second law of thermodynamics: within periods of time considerably shorter than the duration of evolutionary changes, living systems can only lose the accumulated information (i.e., the entropy can only increase), even if the systems consume external energy–food flows.     

Promoting sustainable development in Ghanaian small-scale gold mining operations

This paper provides an overview of the initiatives that have been undertaken by the Ghanaian government to promote more sustainable development in resident small-scale gold mining operations, and recommends a series of strategies for perpetuating a pattern of continued improvement. Since the passing of the Small Scale Gold Mining Law (PNDCL 218) in 1989, which effectively legalized small-scale gold mining as an industry in Ghana, the government, in particular, the Minerals Commission, has made a concerted effort to regularize operations, and to provide technical and financial support to miners. Under the auspices of the German non-profit Gesellschaft Technishe Zusannebarbeit (GTZ), a small-scale gold mining registration system has been implemented, district support centres for small miners have been constructed and the Precious Minerals Marketing Corporation (PMMC) has been created, which purchases products from small-scale miners at near-market prices. Careful analysis reveals, however, that these efforts have collectively only had a marginal impact, and that the industry is still in dire need of aid. Specifically, to perpetuate further a pattern of improved sustainability--improvements in both the socio-economic and environmental arenas--additional technical and financial support must be provided, and sound environmental management practices implemented. The Minerals Commission has been burdened with these tasks and challenges but because it is largely understaffed, it is highly unlikely that it will be able to facilitate sufficient improvement in the sector on its own. Nevertheless, marked improvements can be achieved if: (1) avenues for technological dissemination are created and improved; (2) research partnerships are forged with local universities; (3) experienced consultation is hired when needed; and (4) other governmental agencies, namely the Mines Department, Environmental Protection Agency (EPA) and Geological Survey, provide the Minerals Commission assistance with prospecting, monitoring, regulation and environmental auditing activities.     

室内皮带上煤机除尘系统改造设计

针对某公司热电厂皮带上煤机除尘系统所存在的问题,进行了全面的改造设计,取得了良好的除尘效果。