Critical issues in the simulation of hot forming operations

The paper deals with the correlations that can be established in the numerical simulation of manufacturing process chains among the process parameters, microstructure evolution, and properties of the final product. With the focus on process chains applied to bulk and sheet metal parts where deformation is carried out in hot working conditions, the paper illustrates through three application cases the role that the analysis of the microstructure evolution plays in the process chains simulations and, in particular, in enhancing the capabilities of the models that are currently implemented in commercial FE codes for predicting the properties of the final part.     

美国电子束焊接技术

本文介绍了过去五十年美国电子束焊接历程材料加工首次采用电子束（EB）始于20世纪初,用于在真空条件下熔化耐火材料。此后,随着电子束两个主要支撑技术（真空工程及电子光学）水平的提高,应用电子束加工其它类型的材料逐步增加,电子束技术不断进步与成熟。目前电子束的应用见附表,从附表中可以看出,电子束应用范围从低功率密度（窄,表层型）到高功率密度（深,渗入型）的变化过程。     

History of the Coking Industry in the United States

This month’s installment presents the history of the eventual decline of beehive coking and the emergence of by-product coking abroad and in the United States.     

History of the Coking Industry in the United States

This month’s installment continues with the history of the emergence of byproduct coking in the United States.     

Critical issues in the OPIT processing of high-Jc BSCCO superconductors

The oxide-powder-in-tube (OPIT) method has produced superconducting wires or tapes that exhibit high critical current densities in high magnetic fields when the superconducting oxide is the two-layer compound Bi₂Sr₂Ca₁Cu₂O_y or the three-layer compound Bi_2?xPb_xSr₂Ca₂Cu₃O_y. For good properties to be obtained, however, numerous critical processing issues must be addressed.     

History of the Coking Industry in the United States

In this last article of a series, the coke industry of today is discussed and some interesting statistics concerning the industry are presented.     

History of the Coking Industry in the United States

During the past several years JOURNAL OF METALS has presented articles on the history of all phases of iron- and steelmaking in the United States. This comprehensive history is the last of these articles. At a future date. The Metallurgical Society anticipates publishing all of these articles in one volume on the History of Iron- and Steelmaking in the United States.     

History of the Coking Industry in the United States

In last month’s Journal of Metals, Part I of this article described the early coke processes employed in the US. This month the article presents a history of the beehive oven era.     

美国钛工业的发展趋势

美国钛工业的规模与技术水平处于世界领先地位。随着世界形势的发展变化,其发展动向由主要用于航天航空、军需而逐渐转向民品和一般产业。但在今后十年中,航天航空和军需上钛的需求仍占主要地位。美国钛合金材料的开发与应用领域比较广泛,汽车行业上的应用也日益受到重视。其它领域的应用正处在积极拓展中。     

Transient Testing of Nuclear Fuels and Materials in the United States

The United States has established that transient irradiation testing is needed to support advanced light water reactors fuel development. The U.S. Department of Energy (DOE) has initiated an effort to reestablish this capability. Restart of the Transient Testing Reactor (TREAT) facility located at the Idaho National Laboratory (INL) is being considered for this purpose. This effort would also include the development of specialized test vehicles to support stagnant capsule and flowing loop tests as well as the enhancement of postirradiation examination capabilities and remote device assembly capabilities at the Hot Fuel Examination Facility. It is anticipated that the capability will be available to support testing by 2018, as required to meet the DOE goals for the development of accident-tolerant LWR fuel designs.     

Critical issues in catalytic diesel reforming for solid oxide fuel cells

Developing low-cost diesel-reforming catalysts and improving fuel mixing prior to catalytic reforming were addressed as two critical issues under the current study. Ruthenium-doped lanthanum chromite and aluminite were explored as catalysts for the autothermal reforming of diesel fuel. Dodecane was used as a surrogate fuel. Both catalysts yielded nearly 20 moles of hydrogen per mole of dodecane at oxygen-to-carbon ratios of 0.5 and steam-to-carbon ratios of 2 at space velocities near 100,000/h⁻¹. Both catalysts were shown to have good S tolerance when tested with a fuel mixture containing 50 parts per million S in the form of dibenzothiophene. Parallel to catalyst development, the impact of fuel mixing and vaporization through improved liquid injection also is under investigation. This paper was presented at the ASM Materials Solutions Conference & Show held October 18–21, 2004 in Columbus, OH.     

美国本科课程改革:追求完整的本科教育

美国历次大学本科教育改革均是通过课程改革实现的,课程改革被视为教育改革的重中之重.20世纪90年代中期以来,美国大学针对本科教育中存在的专业化和职业化倾向加剧,学生人格培养受到影响,本科教育广受社会指责等问题,以整体知识观为理论指导,深入改革本科课程,致力于建立融普通教育和专业教育为一体的连贯和完整的本科课程体系,强调将人文学科的学习作为本科教学战略的基础,学习跨学科课程成为对学生的基本要求,以确保本科教育各个知识系统之间的本质联系,消除狭隘的本科教育的弊端,追求完整的本科教育,帮助学生养成整体的知识观和综合的生活观,使学生能以时代最好的知识成熟地理解事物的本质,承担起公民的职责.