30t及以上轴重重载货车车轮的研发

为满足国内外30t及以上轴重重载货车车轮需求,针对重载车轮损伤特点,设计了两种重载车轮用车轮新材料,与传统的CL60材质车轮钢相比,具有更好的磨损和抗接触疲劳性能。开展了钢中夹杂物塑性化处理技术研究和重载车轮热处理工艺研究,确定了重载车轮钢和车轮关键制造工艺,试制车轮的综合力学性能明显优于CL60材质车轮。     

高性能车轮的开发和试验

对8种高性能车轮进行了评估。实验室试验结果显示它们中有3种车轮在屈服强度方面较AAR C级和参加试验的其他车轮更具优势。采用较小的车轮样品进行了耐久性试验,以获得在几乎全弯道和大轴重加重磨损和疲劳的环境下车轮的性能。装车运营试验142 000km后对大多数试验车轮进行了检查,发现几乎所有车轮保持良好的状态,没有出现较大的剥离。     

电解多功能起重机车轮的疲劳计算

本文针对目前铝电解多功能起重机使用的车轮进行计算分析,建立了车轮踏面最大接触应力与车轮直径、轨道曲率半径及轮压分布等因素的关系,并确定考虑机构工作级别和车轮材料性能的车轮踏面的疲劳极限许用应力,进一步完善了车轮踏面的疲劳计算。同时,对其它类型起重机车轮的疲劳计算也具有指导意义。     

我国车轮生产及工艺发展趋势

文章认为车轮生产能力和产品质量对我国铁路运输的发展至关重要，介绍了国内外整轧车轮工艺装备的发展以及新型整体铸钢车轮工艺研制开发情况，并指出对我国车轮厂进行全面技术改造，再建新的车轮轧制生产线及开展整体铸钢车轮开发应用工作十分必要。     

铝合金车轮的发展现状及展望

通过广泛的调研,汇集了大量有关铝合金车轮行业的资料,归纳了铝合金车轮的全球占有量,阐述了国际企业竞争态势和产品制造工艺。介绍了国内铝合金车轮发展现状,并对铝合金车轮的发展前景进行了展望。     

车轮用钢断裂力学性能研究

对国产Ｒ７、Ｒ８和ＧＬ６０辗钢车轮，巴西辗钢车轮及美国Ａｂｅｘ公司和Ｇｒｉｆｆｉｎ公司的铸钢车轮用钢的断裂力学性能进行了对比研究。结果表明，国产车轮钢疲劳裂纹萌生抗力高于国外车轮钢，Ｒ７钢裂纹萌生抗力最高，六种车轮钢的疲劳门槛值相当，稳态阶段的疲劳裂纹扩展速率也相差不大，国产车轮和巴西车轮钢断裂韧性Ｋｏ值较Ａｂｅｘ和Ｇｒｉｆｆｉｎ车轮钢大。结合断口作了初步分析。     

高硬度车轮在热处理中关键元素的控制

为了满足客户对高硬度车轮的性能指标要求,基于马钢车轮产品热处理工艺的实际情况,提出了高硬度车轮在热处理过程中的关键控制元素,结果表明:通过对高硬度车轮的材质、淬火前加热、淬火、回火等元素的控制,生产的高硬度车轮的性能指标稳定,达到了客户的要求,实现了批量生产。     

冶金车辆车轮组的改进

利用无键偏心轴承座,对车轮组进行改进。经过改进后的车轮组,能够调节车轮水平偏斜角度,消除啃轨现象,并且使用胀紧连接套联结车轮实现装拆车轮组方便,降低加工精度,节省了成本。     

烧结机台车轮掉落研究

烧结机是钢铁行业重要的工艺设备。对烧结机台车轮掉落的原因进行了分析，并介绍了烧烧结产线对台车轮掉落问题改进措施，并重点阐述了一种改进后的台车轮结构。该两条产线自实施相关措施后，已成功杜绝台车轮掉落，为烧结同行业解决台车轮掉落问题提供了参考。     

打造车轮民族品牌 建设一流轮轴企业

马钢车轮轮箍厂经过50多年的艰苦奋斗、滚动发展、不断创新,从昔日仅能够生产铁标客车轮、铁标货车轮、整体机车车轮、大功率机车轮、弹性车轮、低噪音地铁车轮、重载车轮、高速车轮,以及机车轮箍、环型件等全系列车轮轮箍产品,到拥有轨道交通用钢、箍环、车轮、车轴和轮对完整产业链,有马钢交材公司、马钢轨道交通公司、法国(马钢)瓦顿公司三大制造基地,形成在国际具有较强市场竞争力和影响力的轮轴企业和全球最大的碾钢车轮专业生产厂,马钢车轮也荣获了“中国名牌产品”的称号。     

NMR in high-pressure phases of solid NH3 and ND3

Construction materials management is generally recognized to be the integrated coordination of materials takeoff, purchasing, expediting, receiving, warehousing and distribution. When these functions are not properly managed, materials shortages, surpluses, and cash flow problems are likely to occur. Costly labor delays result when the required quantity or quality of materials are not available when needed. The attributes of materials management systems are discussed and the essential elements of a successful system identified. Owner‐contractor, engineer‐contractor, and home office‐project site communications appear to be critical to the success of the materials management effort. Preconstruction materials planning and personnel orientation and training are also important. The complex online computer programs that are used to coordinate the materials management effort are costly, but essential, if the desired degree of control is to be exerted to prevent potential shortages, surpluses, and cash flow problems.     

Evaluation of prescription opioids using operant-based pain measures in rats.

Opioids are the most effective compounds available for the relief of pain, yet there are a number of side effects that are of great concern to clinicians. For example, opioids are powerful reinforcers, and the treatment of pain using opioids could lead to the development of addiction. In addition, there is an increasing body of literature demonstrating that the repeated administration of opioids could lead to a phenomenon called opioid-induced hyperalgesia (i.e., increased sensitivity to painful stimulation). Studies examining these potential adverse effects are necessary in the development of novel analgesics. Furthermore, most studies of pain sensitivity and pain relief use reflex-based procedures to identify analgesics; however, it is argued here that operant-based procedures provide measures that are more analogous to the human condition (i.e., the mechanisms of pain are similar to those in humans) and should be useful in the assessment of novel analgesics. A series of studies examining the effects of opioids and the influence of variables such as age are discussed to demonstrate the utility of this approach. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Authority Structures for Construction Project Management

Many practitioners believe that how one organizes to support a major construction project will have a significant impact on the successful completion of the project. This paper provides a primer on authority structures. The basic corporate organizational forms are described and construction examples are given. The basic authority structures for project management are also described. These forms are the functional, pure project, and matrix. For each form, the advantages and disadvantages as they relate to the project manager's ability to support the project are cited. Nine factors that influence the choice of authority structure are discussed. The role of the project manager is described. His effectiveness as a manager is related to the organizational form, hierarchy within the organization, authority gap, management style, and the ability to resolve conflict. Six principles for developing a project organization and selecting a project manager are given.     

Analysis of Rim Supports for Off‐Axis Inflatable Reflectors. I: Loads

A structural analysis is performed for the rim support of a pressurized off‐axis paraboloidal membrane, serving as a space‐based solar concentrator. The function of the rim support is to take up the tensile forces created by the stretched membrane. This paper deals with the load analysis. The tensile forces transmitted by the membrane to the rim support are calculated, and are proportional to pb, where p is the inflation pressure and b is one‐half the major axis of the elliptical rim. Next, the internal forces and moments generated in the rim support by the membrane forces are calculated. The compression forces are considerably larger, at any point, than the shear forces; both are proportional to pb2. The bending moments are proportional to pb3. The critical point is found to be at the top of the rim, where both the bending moment and compression force are at their maximum.     

Statistical Lifetime Predictions for Aramid Fibers

This paper investigates the statistical procedures that can be used to analyze stress rupture data for aramid yarns, with a view to making reasonable predictions for the allowable prestress levels in parallel-lay ropes or fiber-reinforced polymer tendons for use as prestressing tendons in concrete structures. Two existing data sets are combined and used to illustrate the principles that are being discussed. Arrhenius, exponential, and inverse power physical models are used with Weibull and lognormal statistical distributions. A wide range of variations of the scale and shape parameters are analyzed. Various statistical criteria are used to reject models that are not statistically secure, and the Kullback-Liebler and Akaike information criteria are used to further limit and rank the possible models. The results show that there is still a large range of possible predictions for the long-term stress-rupture lifetime of aramid yarns, but also that statistical models are available for investigating further test work that needs to be carried out.     

Application scenarios for nonstandard log-linear models.

In this article, the authors have 2 aims. First, hierarchical, nonhierarchical, and nonstandard log-linear models are defined. Second, application scenarios are presented for nonhierarchical and nonstandard models, with illustrations of where these scenarios can occur. Parameters can be interpreted in regard to their formal meaning and in regard to their magnitude. The interpretation of the meaning of parameters is the main focus of this article. Design matrices are used to describe the hypotheses tested in models and to illustrate cases in which parameters are interpretable. Also, design matrices are used to show where and how nonstandard models differ from standard hierarchical models. Coding schemes are discussed, in particular, dummy coding and effects coding. Data examples are given with data and models discussed in the literature. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Optimum Design of Welded Steel Plate Girder Bridges Using a Genetic Algorithm with Elitism

The genetic algorithm (GA) is a general optimization technique that has some unique features that are especially suitable for structural engineering problems. This work uses a simple GA with elitism to find the optimum design of welded steel plate girder bridges. The objectives are to minimize the weight and the cost of the girders. Two types of plate-girder bridges are studied: a single-span bridge and a two-equal-span continuous bridge. Bridges with various span lengths, in increments of 20?ft, are investigated; results are tabulated, parametric studies are made, and meaningful conclusions are drawn.     

Child-Centered Play Therapy with Children who are Homeless: Perspective and Procedures.

Children who are homeless are one of the fastest growing populations. However, the literature on play therapy with children who are homeless is sparse. This article provides play therapists with needed perspective of prevalence, causes, and mental health impact of homelessness. A Child-Centered Play Therapy approach, which emphasizes a safe relationship based on the core conditions, is recommended. Procedures to meet the needs of children who are homeless and to enlarge the meaning of their unique play themes, such as eviction and "I'm rich," are discussed. Play therapists are encouraged to fulfill their social responsibility by providing play therapy for children who are homeless. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Evaluation of Uplift Interpretation Criteria for Drilled Shaft Capacity

Representative interpretation criteria are examined to evaluate the capacity of drilled shaft foundations under axial uplift loading. A wide variety of uplift load test data are used, and these data are divided into drained and undrained databases. The interpretation criteria are applied to these load test data to establish a consistent uplift interpretation criterion. The results are comparable for both drained and undrained loading. In general, the undrained load test results show somewhat less variability than the drained results. Based on these analyses, the QL2, Q0.5in, and slope tangent methods are the more reliable and consistent, and specific design recommendations for the interpretation of uplift drilled shaft load test are given, in terms of both capacity and displacement.     

港口起重机工作状态防风能力现状与对策

突发阵风是威胁港口起重机工作状态安全最严重的自然灾害,提高港口起重机工作状态防风能力和提高制动装置的可靠性意义非常重大.以具体的港口起重机为例,对其工作状态设计所需防风能力和配置的防风制动装置能力进行详细计算,研究大车制动器、夹轨器、轮边制动器设计防风能力与实际作用效果差异,得出港口起重机几种类型防风制动器的合理配置关系,以提高防风制动器的作用效果.同时,根据防风制动装置制动能力的实测数据及测试现象,分析防风制动器设计理论存在的局限性,找出港口起重机工作状态防风能力薄弱环节,给出提高和增强港口起重机工作状态防风能力对策.