不稳定岩层中平巷掘进的悬拱法

本文在总结先拱后墙平巷掘进经验的基础上，根据射 石力学理论和平巷掘进原理，提出了平巷掘进的悬拱法。实践证明，悬地是不稳定岩层中平巷掘进的有效施工方法。     

TRT6000水文地质探测仪在田兴铁矿中的应用

介绍了司家营田兴铁矿采选工程概况以及TRT6000超前地质预报仪器在田兴铁矿平巷及斜坡道施工中的应用.采用成像技术,生成工作面前方地层结构的全息三维图,取得良好的探测效果.实践证明,探测前方100 m内的地质情况,与实际情况基本相符.说明了TRT6000超前地质预报在平巷及斜坡道施工过程中的重要性,能够指导平巷及斜坡道安全快速施工,降低井巷施工成本.     

高深度大断面中深孔一次成井技术探索与应用

文章介绍了井下矿开采的"高深度大断面中深孔爆破一次成井施工技术",一次成井施工工艺能够替代人工施工切割天井.该工艺中,施工人员在平巷内操作凿岩台车施工上向垂直炮孔,装药也在平巷内完成,作业空间高度小,顶板风险可控,利用平巷做补偿空间,采用延期爆破一次成井,施工效率高、施工简单、机械化作业、安全风险小、劳动强度低,可在井...     

平巷钻进法的现状与发展趋势

平巷掘进机是一种能实现破岩、装岩、转载、支护、喷雾防空等全部机械化的联合机组。它具有机械化程度高,施工速度快,效率高和工作安全等优点。因此,国内外都在积极研制、应用。国内外大量施工实践证明,平巷掘进机掘进是一种有广泛发展前途的施工方法。     

不稳定矿岩巷道掘进支护方法简述

镜铁山矿采用插管法和超前锚杆支护法 ,顺利通过了不稳定矿岩 ,成功地解决了破碎矿岩的平巷掘进问题 ,积累了在不稳定矿岩中平巷掘进施工的经验。     

提高平巷掘进爆破率的实践

针对平巷掘进爆破效率较低的问题,通过分析其主要影响因素,确定了合理的掏槽方法和爆破参数.施工实践表明,平巷掘进爆破率得到了提高,并且取得良好的经济效益.     

在坚固岩层中提高平巷掘进爆破率的实践

针对在坚固岩层中平巷掘进爆破效率较低的问题,通过分析其主要影响因素,确定了合理的掏槽方法和爆破参数;施工实践表明:平巷掘进爆破率得到了提高,并且取得了良好的经济效益。     

提高平巷掘进爆破率的实践

针对平巷掘进爆破效率较低的问题，通过分析其主要影响因素，确定了合理的掏槽方法和爆破参数，施工实践表明，平巷掘进爆破率得到了提高，并且取得良好的经济效益。     

电磁雷管在矿井大断面岩巷掘进中的应用

通过对某矿平巷大断面掘进过程中放炮工艺的改进,提高了工作效率及施工速度     

论平巷掘进施工的成本控制措施

通过分析平巷施工成本构成，探讨了炮眼利用率、超挖及欠挖、炮眼数目、单位炸药消耗量、炮眼深度、工序安排、巷道作业面的数目、巷道的掘进速度等影响平巷成本的因素，提出通过采用2．5m深炮眼、光面爆破技术、选择合理的炮眼密集系数和炮眼装药满度系数，组织多头平行作业等措施控制成本。     

Addition of Cobalt to Lead Anodes Used for Oxygen Evolution—A Literature Review

A review of the literature dealing with the effect of cobalt on lead-based anodes for oxygen evolution during electrolysis of sulfuric acid solutions verifies that the presence of cobalt at the anode–electrolyte interface, either as constituent of the anode material or as ions in the electrolyte, catalyzes the evolution of oxygen and reduces the corrosion of the anodes and the contamination by lead of metal cathodes produced during electrowinning. However, due to harmful effects of cobalt ions on the cathodic reaction in some processes, these benefits are limited to the electrowinning of copper. Efforts to develop a way of introducing cobalt at the anode–electrolyte interface without interfering with the cathodic reactions are reviewed in this paper. The use of lead–cobalt alloy anodes has had limited success due to issues arising from the low solubility of cobalt in lead, segregation during casting of the alloys, and nonuniform distribution of cobalt which affects the integrity of the anodes. This has been overcome in part lately by inclusion of cobalt into only the surface layer of a lead or lead alloy substrate, by thermal treatment of a cobalt salt to form a catalytic cobalt oxide surface species, or by electrodeposition of composite lead–cobalt oxide anodes. The last approach in particular has been actively investigated by several groups, but to our knowledge it is yet to find application in the industry. The review also critically examines the likely reaction mechanisms involved.     

A review of effects of silver,lead, sulfide and carbonaceous matter on gold cyanidation and mechanistic interpretation

Despite the wealth of published data on the beneficial or detrimental effects of silver, lead, sulfide, and carbonaceous matter on the rate of gold cyanidation at an anode or by dissolved oxygen, the lack of comparative studies on relative effects has hampered rationalisation of the role of these activators or passivators of gold. In the present study, the published rate data per unit surface area of gold, silver, and gold–silver alloys based on electrochemical or chemical dissolution of rotating discs or foils of constant surface area in aerated cyanide solutions at ambient temperatures are analysed on the basis of the Levich equation. The current status of the reaction mechanism is also reviewed and updated on the basis of species distribution and potential–pH diagrams, stoichiometric factors, and interim chemical species of gold(I), silver(I), and lead(II). The anodic peak potentials of reported voltammograms closely follow the potential–pH lines of Au(I)/Au(0) and Pb(II)/Pb(0) couples. Despite the formation of stable complexes between lead(II), nitrate, and hydroxide ions, the total calculated soluble lead(II) in alkaline solutions of pH range 10–11 saturated with lead hydroxide is shown to be < 0.1 g/m³. A comparison of the reported diffusion coefficients of cyanide ions and dissolved oxygen with the values based on the Levich plots of reported rates reveals the rate-controlling stoichiometric M/CN or M/O₂ molar ratios. The difference between some of these ratios and the generally accepted ratios of M/CN = 1/2 and M/O₂ = 1/0.5 or 1/0.25 based on the formation of M(CN)₂⁻, H₂O₂ or OH⁻ in the overall cyanidation reaction is attributed to the oxidation of cyanide to cyanate and passivation due to the formation of gold hydroxides/oxides. The alloyed or dissolved silver and lead eliminate passivation due to the involvement of mixed hydroxo–cyano complexes of silver and lead ions in the surface reaction. Gold dissolution by oxygen in cyanide-rich solutions is limited by oxygen diffusion, but enhanced by the presence of a low concentration of sodium sulfide due to the involvement of hydrosulfide ion in the surface reaction. However, excess lead or sulfide retards gold cyanidation due to surface blockage by metallic lead, lead hydroxide, or due to passivation by Au₂S/S. Even low concentrations of hydrosulfide passivate gold–silver alloys due to the formation of Ag₂S. This can be eliminated by adding stoichiometric quantities of lead(II) to precipitate sulfide as PbS. Large stoichiometric ratios of O₂/M for the cyanidation of graphite coated gold appears to be a result of the enhanced oxidation of cyanide by oxygen or hydrogen peroxide, leading to a cyanide deficiency at the surface and passivation of gold by hydroxide/oxide. The presence of excess cyanide or lead(II) does not override this effect.     

Sham reasoning, Humpty Dumpty, and the burden of proof.

Slife and Reber ask of psychologists that they recognize their prejudice against theism and the incompatibility between theistic and naturalistic worldviews. Yet, the subtext of their article is that theism and naturalism are equally valid and that psychology’s secularism is a mistake. Given that theism is not beyond reason, the only sufficient ground for charging psychologists with prejudice is if (i) theism has survived serious attempts at conceptual and empirical test, and (ii) psychology ignores or disguises this fact. So, the grounds for believing in the reality of a supernatural existent are highly relevant to the authors’ allegation. However, their concept of God affords no such grounds. They disavow the logic involved in the ordinary meaning of the term “incompatible” and they ignore a crucial distinction between conditions of existence and qualities of things or processes. The consequence is that either God is this-worldly, and there is no ontological basis to Slife and Reber’s incompatibility thesis, or God’s mode of existence is quite different from the mode of existence of ordinary things and all the problems of dualism follow. Either way, their charge of prejudice is without foundation. The burden of proof rests with the defender of theism and, for now, psychology’s secularism can be considered a mark of the discipline’s (sometimes questionable) rationality. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Failure Resistance of Historic Stone Bridge Structure of Charles Bridge. II: Susceptibility to Floods

The paper is a follow-up to the first part devoted to an analogical problem investigated with a view to the degradation of the stone structure due to the effects of nonstress load, and it deals with the probability problem of the bridge structure collapse under the effect of an extreme flood wave. The paper presents the results of the numerical analysis of the response of the historic stone bridge structure of Charles Bridge of the 14th century to the flood wave effect simulated by angular rotation, subsidence, and shifting in the footing bottom of a bridge pier. Special focus is on the effect of interventions into the stone bridge structure dating back to the last major overhaul of 1967–1975, particularly, on the effect of the reinforced concrete slab (tie plate) connecting the opposite bridge breast walls increasing the rigidity of the breast walls and their structurally efficient connection to the vaults of the bridge arches. The numerical analyses performed point out the prevailing negative effects of the implemented interventions in terms of structural rigidity of the stone bridge structure exposed to the effect of a flood wave.     

Reliability-Based Design for External Stability of Mechanically Stabilized Earth Walls

A two-phase approach was used to develop a reliability-based design (RBD) method for external stability of mechanically stabilized earth (MSE) walls. In the first phase, a parametric study was conducted using Monte Carlo simulation to identify parameters that affect the probability of external failure of MSE walls. Three modes of failure were considered: sliding, overturning, and bearing capacity. External stability was assessed by treating the reinforced soil as a rigid mass using the same procedures employed for conventional gravity-type wall systems. Results from the parametric study indicate that the mean and coefficient of variation of the backfill friction angle are significant for sliding, the mean and coefficient of variation of the friction angle of the backfill and coefficient of variation of the unit weight of the backfill are significant for overturning, and the mean and coefficient of variation of the friction angle of the foundation soil and the mean of the backfill friction angle are significant for bearing capacity. In the second phase, a series of additional simulations was conducted where the significant parameters identified in the parametric study were varied over a broad range. Results of these simulations were used to develop a set of RBD charts for external stability of MSE walls. A comparison indicates that similar reinforcement lengths are obtained using RBD and conventional methods and that the inherent probability of external failure in conventional deterministic design is ? 0.001. This probability of external failure is similar to inherent probability of failure reported by other investigators for similar geotechnical structures.     

Response Surface Models to Detect and Localize Distributed Cracks in a Complex Continuum

Linear response surface (RS) models are used to represent the relationship between samples of response time histories measured by sensors placed across a structure. Different structural states of a general time-variant system are considered for short intervals capturing a linearized model of each state. Within this framework, the error associated with each RS model is sensitive to a modification of the structural state. A method that relates the changes of the statistical characterization of the error to the occurrence of a structural modification is developed for damage detection. The localization of damage is then pursued by identifying the largest discrepancies resulting from the comparison between the statistics of the sum of the squares of the error obtained at each sensor location. The generality of the method is shown by applying it to the experimental data of a realistic structure, which is representative of a continuous body affected by distributed cracking.     

New Orleans Levee System Performance during Hurricane Katrina: London Avenue and Orleans Canal South

Hurricane Katrina was one of the worst natural disasters in U.S. history. The effects of the hurricane were particularly devastating in the city of New Orleans. Most of the damage was due to the failure of the levee system that surrounds the city to protect it from flooding. This paper presents the results of centrifuge models conducted at Rensselaer Polytechnic Institute and the U.S. Army Corps of Engineers simulating the behavior of the levees at London Avenue North and South that failed during Hurricane Katrina. Those levees failed without being overtopped by the storm surge. Also included are the results of a centrifuge model of one levee section at Orleans Canal South, which did not fail during the hurricane. The key factor of the failure mechanism of the London Avenue levees was the formation of a gap between the flooded side of the levee and the sheetpile. This gap triggered a reduction of the strength at the foundation of the protected side of the levee. The results are fully consistent with field observations.     

铜,砷矿物类型对金氰化浸出的影响及如何提高其浸出率的探讨

本文引用了某些理论研究的成果，考察了含铜，含砷矿物在氰化溶液中的行为和对金氰化浸出的影响的规律，找出金浸出率与各种有害矿物含量的相关关系，为制定难选金工艺方案时参考。并结合小型试验和工业实践，对矿石性质作深入了研究，同时其浸出工艺条件也进行了最佳选择和应用，为提高金的浸出率进行了讨论。     

Measuring students' connectedness to school, teachers, and family: Validation of three scales.

Connectedness to school, teachers, and family are all significant protective factors in adolescents' lives, yet the measurement of each varies considerably. This article describes the measurement properties of three composite scales of adolescent connectedness, adapted from the Add Health study and the California Healthy Kids Survey. These composite scales are created by either summing or taking the mean of all individual items, measured on an ordinal scale. This approach fails to account for the ordinal, non-normal nature of the data. Using a covariance approach, this article describes the measurement properties of the latent constructs of connectedness to school, teachers, and family and the contribution of each of the items used to compile the relevant composite score. The outcomes of this study will provide researchers and practitioners with information about the validity, reliability, and overall usefulness of each of the measures of adolescents' perception of their connectedness to school, teachers, and family. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Social psychoanalytic research and the twenty-first-century family: Comment on Wallerstein and Lewis (2007).

Seligman regards Wallerstein and Lewis' paper (see record 2007-10890-004) as an exemplary piece of social-developmental psychoanalytic research, finding it accessible, activist and empirical. He admires Wallerstein and Lewis' careful attention to the influence of social reality on the development of the internal worlds of both children and adults, following a psychoanalytic tradition which has been neglected recently. Since actual family configurations are changing so rapidly in the current American situation, analysts should develop new theoretical and research approaches that reflect these changing realities. Seligman highlights two specific implications of such adaptive shifts: the de-centering of the Oedipus complex as the standard form of psychosocial-family organization of the personality, and increased attention to the role of sibling relationships in development. He calls for more analytic clinical research efforts that will apply the substantial potentials of social-psychoanalytic research in service of the varying groups of children who are suffering in the midst of the array of psychosocial strains in the contemporary culture. (PsycINFO Database Record (c) 2010 APA, all rights reserved)