导辊裂纹产生原因分析及消除方法

通过对导辊的状况、导辊材料、热疲劳等因素的分析，找出了导辊裂纹产生的原因是；材料热物理性能偏低，以及导辊制造过程中所存在的缺陷。提出消除纹的方法是：提高导辊材料的导热性和严格控制导辊生产质量，并进行适当热处理以消除残余应力。     

四辊轧机牌坊裂纹分析及解决方案

针对武钢热轧总厂中厚板分厂四辊轧机牌坊连续多年在导卫连接处出现裂纹的问题,分析了牌坊导卫处瞬间载荷,并对牌坊与导卫的连接结构进行改进,降低了牌坊工作时所受的瞬间载荷。     

铝铸轧辊套的热疲劳及材料合理选择

简明扼要地分析了铝铸轧辊辊套内外表面的温度变化及辊套内热应力的形成及其变化规律，着重论述了辊套表面热裂纹的形成与扩展，提出了修正辊套表面热裂纹的措施及合理选择抗热疲劳辊套材料的要求，认为32Cr3MolV钢是一种较好的抗热疲劳裂纹的辊套专用材料。     

高性能冷轧辊的研究和选用

冷轧工作辊最常见的损坏是辊面裂纹和剥落，通过提高冷轧辊抗裂性的研究，选用了含Cr3%和5％的轧辊材料，采用强韧化热处理、电渣重溶等加工工艺，大大提高了冷轧辊耐裂纹能力，提高了冷轧辊使用寿命。     

导辊磨损原因分析及改善方法

通过对导辊工作条件和温度场的分析，找出了导辊磨损过快的原因在于工作时导辊温度过高，提出了以改善冷却条件为导辊磨损过快问题的解决方法。     

提高轧机导卫辊寿命的研究

在分析棒、线材轧机使用的Gx铸造合金导卫轶失效形式的基础上，对不同热处理状态的GJH-2合金和Gx铸造合金，在不同温度下的高温磨损特性进行了对比试验，并将GJH-2合金制成导卫辊在轧机上进行了装机试验，试验结果表明，用GJH-2合金代替Gx铸造合金制作导卫辊可以大幅度提高导卫辊的使用寿命和经济效益，GJH-2合金导卫辊的使用寿命是Gx铸造合金辊的16.5倍。     

320／150轧机使用辊式进口导卫装置轧制角钢

白俄罗斯钢铁厂３２０／１５０连续小型－线材轧机在生产小型角钢时，使用了自行设计的进口辊式导卫，该导卫的特点是具有成型的水平导辊和专用的冷却系统。文中这种辊式导卫的结构，设计特点和控制轧件的能力论述。     

降低板坯角部裂纹生产实践

采取结晶器和二冷区弱冷制度、恒拉速浇铸、控制结晶器钢液面波动在±3 mm以内、采用合适的结晶器窄面锥度、适当提高保护渣碱度、保证扇形段导辊对弧精度和辊缝偏差在±0.5 mm以内、保证结晶器振动偏差在±0.3 mm以内等措施,可以有效降低连铸坯角部裂纹程度和裂纹发生率,降低热轧板卷降级比例。     

高碳高速钢导辊的研究和应用

导辊是高速线材轧机上的主要消耗工具，要求高耐磨性，抗粘钢性和热疲劳抗力。普通奥氏体耐热钢、马氏体耐磨钢或耐磨铸铁导辊满足不了上述要求，使用寿命短，降低了轧机作业率。硬质合金导辊具有良好的耐磨性和高温稳定性，使用效果好，但生产成本高。高碳高速钢具有硬度高、红硬性和耐磨性好等特点，但铸造高速钢脆性大，采用RE－Mg-Ti复合变质处理，可以改变共晶碳化物的形态和分布，使铸造高速钢冲击韧性提高86.2%，热疲劳抗力和耐磨性也明显改善。变质处理高速钢导辊使用中不粘钢、不破碎、不剥落，使用寿命比高Ni-Cr合金铸钢导辊提高3倍以上，接近硬质合金导辊。     

连铸坯中心裂纹产生的机理

铸坯的一形裂纹产生在坯厚中间位置。这种中心裂纹在很多情况下都不能在轧制过程中消除，从而成为缺陷。本文通过对中心裂纹的研究及相关操作条件的分析，探讨了其形成机理，结果如下。（１）中心裂纹是被封在靠近液相穴末端（顶端）的钢液冷却收缩所形成的缩孔。（２）根据形成的孔穴尺寸而算出的被封入钢液厚度约为６ｍｍ。（３）缺陷的尺寸与矫直点附近导辊的工作状态有关。（４）中心裂纹易出现在危险的铸速范围。     

Rapid Bridge Replacement under Emergency Situation: Case Study

The terrorist attack on September 11, 2001, and subsequent potential threats to the United States transportation systems have presented an urgent need to elevate the security of the transportation infrastructure and to develop emergency response plans to quickly react to the possible consequences of an extreme event. Highway bridges, as critical components of the nation’s transportation network, have been brought to closer attention by government agencies. A research project was conducted to identify strategies and technologies to restore the use of a damaged bridge quickly. One of the tasks associated with the research was to perform several case studies of previous bridge replacements following extreme events. These events include explosion and fire caused by vehicle impact, vessel collision with a bridge, and damage caused by flood and earthquake. By studying the cases, the research team seeks to identify and expand on lessons learned and address which actions did and did not work well given the circumstances of the incident. These lessons have great value to the people who need to develop and implement an emergency response plan.     

Compatibility with Jet A-1 of a GCL Subjected to Freeze–Thaw Cycles

Needle-punched geosynthetic clay liner (GCL) specimens subjected to 0, 5, and 12 freeze–thaw cycles in the laboratory, and GCL specimens recovered from a composite barrier wall in the Canadian Arctic after 1 and 3 years were examined to assess the hydraulic conductivity/permeability with respect to both deionized deaired water and Jet A-l. The GCL specimens recovered from the field after 3 years had a hydraulic conductivity with respect to water that was approximately 30% less than that of the GCL specimens subjected to 12 initial freeze–thaw cycles in the laboratory, suggesting that the laboratory conditions are more severe than field conditions. The combined effects of both the freeze–thaw cycles and Jet A-l permeation increased the permeability. This increase is attributed to the creation of macropores in the GCL due to freezing and to an expansion of free-pore space due to contraction of the double layer caused by permeation of Jet A-l. Although there was an increase in permeability due to the combined effect of freeze–thaw and permeation by Jet A-l, the effect was relatively small and the results suggest that the GCL continued to exhibit good performance as a hydraulic barrier when subject to extreme climatic conditions and hydrocarbons both in the laboratory and in the field.     

Report of the Treasurer: 1980: Onward, financially and morally.

APA is in very good shape financially as a result of procedures and attitudes within the Council of Representatives and elsewhere in the Association's governance. We are able to maintain a balanced budget and to enjoy surpluses--though we can be certain that this will not continue forever--and at the same time to be reasonably solicitous of personal and social needs of the disadvantaged in our midst. At a time when the federal government finds it necessary to abandon or drastically cut programs to help the voiceless and other victims of our society, it is heartening to note that in our small way we psychologists are able to walk both sides of the street, that is, to help those who need our help, but to do so without imperiling our financial solvency. Despite spiraling inflation, the Association continues to produce a surplus from operations, as mandated by the Council of Representatives, while being responsive to the needs of the membership in a swiftly changing environment. In addition to the goal of building our reserves, we are dedicated to the continuation of all existing APA programs in our constant attempts to advance psychology as a science and profession and as a means of promoting human welfare. Financial statements for 1979-1981 are provided. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Probability of Project Completion Using Stochastic Project Scheduling Simulation

This paper introduces a software, Stochastic Project Scheduling Simulation (SPSS), developed to measure the probability to complete a project in a certain time specified by the user. To deliver a project by a completion date committed to in a contract, a number of activities need to be carried out. The time that an entire project takes to complete and the activities that determine total project duration are always questionable because of the randomness and stochastic nature of the activities’ durations. Predicting a project completion probability is valuable, particularly at the time of bidding. The SPSS finds the longest path in a network and runs the network a number of times specified by the user and calculates the stochastic probability to complete the project in the specified time. The SPSS can be used by a contractor: (1) to predict the probability to deliver the project in a given time frame and (2) to assess its capabilities to meet the contractual requirement before bidding. The SPSS can also be used by a construction owner to quantify and analyze the risks involved in the schedule. The benefits of the tool to researchers are: (1) to solve program evaluation and review technique problems; (2) to complement Monte Carlo simulation by applying the concept of project network modeling and scheduling with probabilistic and stochastic activities via a web based Java Simulation which is operateable over the Internet, and (3) to open a way to compare a project network having different distribution functions.     

Performance of a Combined Natural Wastewater Treatment System in West Texas

A study of performance of a combined natural wastewater treatment system was conducted in an arid and semiarid area of West Texas from October 2005 to September 2007. This study investigated the organic matter and nitrogen removal capability in a municipal wastewater land application system following a pond system. Municipal wastewater from the city of Littlefield, Tex. was pretreated by a pond system, and the secondary wastewater effluent from the pond system was surface applied to sprayfield at the wastewater treatment plant and the city farm. The 16 lysimeters were installed in situ to collect the leached water passing the grass root zone. The water samples were taken from the storage pond and the lysimeters for analysis of chemical oxygen demand (COD), total nitrogen, nitrate nitrogen, and ammonia nitrogen. The data show that the pond system played an important role in the treatment. The pond system pretreated COD in the municipal wastewater to the range of 10 to 127 mg/L, total nitrogen to the range of 5 to 19 mg/L, nitrate nitrogen to the range of 2.4 to 8.2 mg/L, and ammonia nitrogen to the range of 0.01 to 6.4 mg/L. The average mass removals and cumulative mass removals were 94 and 96% for total nitrogen, 92 and 93% for nitrate nitrogen, and 96 and 100% for ammonia nitrogen, respectively. There was no potential nitrogen contamination to groundwater found during the research period. The study illustrated that this type of combined natural wastewater treatment system can be used to effectively treat and safely dispose municipal wastewater, and save freshwater used for agricultural irrigation in arid and semiarid area.     

Teachable Moments and the Tyranny of the Syllabus: September 11 Case

The September 11, 2001, terrorist attacks on the World Trade Center and the Pentagon presented unique teachable moments to engineering educators but with the competing demand to complete the course as designed and as dictated by the tyranny of the syllabus. A questionnaire was administered to undergraduate students enrolled in three professional ethics courses in 2001 and 2002 to ascertain the extent to which their instructors used the events as teachable moments. For comparison, the questionnaire was administered 1 year after the attacks to students enrolled in courses of an academic enrichment program at Duke University and environmental science students at North Carolina Central University. The percentage of courses addressing the events was highest in the Fall 2001 semester, when the attacks occurred, falling in the Spring 2002 semester, but increasing in Fall 2002. Most respondents supported the use of the events as teachable moments even if the syllabus and course outline had to be adjusted. The results indicate that engineering education must be open to opportunities to teach physical science and engineering concepts and to introduce the students to the social sciences and humanities.     

Construction Engineering Education: History and Challenge

Engineering has been defined as the vocation of guiding nature to produce something needed or desired. A historical review of the evolution of engineering and engineering education leads to the conclusion that sustainability in design and construction requires the engineer to approach nature with imagination and humility. As part of its Engineer of 2020 initiative, the National Academy of Engineering in 2001 questioned how engineering education should evolve to prepare the profession for the future. From that work and efforts by ASCE, it is clear that an educational system that fails to provide engineers with a broad base of learning results in graduates ill-prepared to enter professional practice. The National Academy Engineer of 2020 work and ASCE Policy Statement 465, “Academic Prerequisites for Licensure and Professional Practice,” echo a call to adopt a new educational model. The new model seeks to strengthen the cognitive ability of engineers and leads them to practices that work in cooperation and harmony with nature for the benefit of society.     

Helping American soldiers in time of war: Reply to comments on the comprehensive soldier fitness special issue.

Seligman responds to the comments made about the January 2011 American Psychologist Special Issue on Comprehensive Soldier Fitness (CSF). Seligman proposed an entire issue of on the topic of CSF to encourage psychologists to come to the aid of our government, and he urges psychologists not to be discouraged by this tactic. He and his coauthors in the special issue are proud to provide their knowledge and their skills to American soldiers. They dearly hope these interventions work and that soldiers benefit. They are strongly for peace and for conflict resolution, and that is what advocacy directed to Congress and to the White House is for. The Army, however, carries out the orders of our politicians, and in doing so, deserves the very best that psychology can offer by way of prevention and treatment. (PsycINFO Database Record (c) 2011 APA, all rights reserved)     

Psychotherapy and Magic.

Discusses the extent to which the practice of psychotherapy places stress upon its practitioners similar to those experienced by the native fisherman of the Trobriand society, and the extent to which such stresses give rise to magical thinking. The observations in this article are based on a study of Trobriad society by Malinowski (in J. Needham's Science, Religion, and Reality). The author concludes that the ideal temperament for the psychotherapist if he is to behave rationally in his work involves the ability to reject the magic which the uncertainties of his task and the demands of his patients throw upon him; to be flexible enough to change his views when the need is clearly indicated, but not to be a weathervane; and to be happy enough in his personal, extratherapeutic life to accept failures as part of the day's work. (PsycINFO Database Record (c) 2010 APA, all rights reserved)