Prediction of H2 Content and Inert Gas Circulation Rate Effects on Batch Annealing Process

Steel strip coils need to be annealed after they leave the cold-rolling process. The purpose of annealing is to improve steel strip formability and to remove residual internal stresses imparted during rolling. Simultaneous increase of circulation rate and inert gas hydrogen content may have considerable effects on reducing the annealing process time. A mathematical model was developed to obtain a more accurate evaluation of the effects of these two parameters on heating and cooling cycles in the annealing process. The results from the simulation of an ordinary annealing process by the proposed model were compared with values measured at site and the accuracy of the model was confirmed. Finally, the effects of increasing hydrogen content and circulation rate were investigated, first independently from each other and then simultaneously. The predictions by the model showed that reduction of annealing time would be considerable when both parameters were simultaneously increased.     

Modeling the supply chain configuration problem with resource constraints

In this paper, we study the supply chain configuration problem (SCCP) under resource constraints. We present a new modeling framework based on multi-mode resource-constrained project scheduling (MRCPSP) for configuring the supply chain subject to explicit resource constraints. It establishes a bridge between the areas of project scheduling and supply chain design. Our model is also able to handle additional practical issues such as quality level requirements and general temporal constraints, which are often encountered in the real world. A constraint programming (CP) based solution approach is proposed and implemented in our case study. Conclusions and future research directions are discussed.     

System for automated fatigue crack growth testing under random loading

Procedures have been developed for computer-controlled crack propagation testing under random load sequences. They include certain features which are not available in conventional systems, but which appear essential for random load testing. These include the capability to simulate any desired K-function on standard laboratory specimens and continuous on-line rainflow analysis of the test load sequence to exclude cycles falling below given values of threshold stress intensity, stress level or range. The system also includes a procedure for automated crack-opening displacement based crack opening/closing load level measurement. Experimental studies on AlCu alloy sheet material point to a requirement for development of standards for spectrum loading crack growth testing.     

A load history generation approach for full-scale accelerated fatigue tests

This paper seeks to establish a load history generation approach for full-scale accelerated fatigue tests. Primary focus is placed on the load cycle identification such as to minimize experimental time while having no significant effects on the new generated load history. The load cycles extracted from an original load history are identified into three kinds of cycles namely main, secondary and carrier cycles. Then the principles are presented to generate the load spectrum for accelerated tests, or a large percentage of small amplitude carrier cycles are deleted, a certain number of secondary cycles are merged, and the main cycle and the sequence between main and secondary cycles are maintained. The core of the generation approach is that explicit criteria for load cycle identification are established and equivalent damage calculation formulae are presented. These quantify the damage for accelerated fatigue tests. Three validation examples of its application for the generation approach of accelerated load histories are given in the paper. Good agreement of experimental lives between the original and generated load histories is obtained. Finally, the generation approach of accelerated load histories is applied to the full-scale accelerated fatigue test of helicopter tail, demonstrating the practical and effective use of the proposed approach.     

金属材料疲劳损伤的电阻研究法

研究三种金属材料的电阻与疲劳伤之间的关系，通过理论分析，得到了电阻与循环粢九的理论关系式，通过实验验证，发现理论计算结果在本实验条件下与实验结果条件很好，说明电阻可以作为研究金属材料疲劳损伤的有效物理参量。     

q(T,T_w)=α(1/T_w-1/T)传热情况下卡诺热泵的最佳供热系数与供热率间的关系

本文导出了卡诺热泵工作于非线性传热q(T,T_W)=a(1/T_W-1/T)的情况下,最佳供热系数CP_0与供热率π间的关系:π=α/(T_HT_L)((T_L-(CP_0-1)/(CP_0)T_H)/(1+δ(CP_0-1)/(CP_)))~2),式中并给出了上述关系的一些应用。     

核燃料循环中的技术与工业演变

本文介绍了从天然铀开采到燃料生产直到后处理的整个燃料循环中的技术和工业演变。核燃料循环的焦点是燃料组件的设计和制造。燃料制造业最重要的发展是以轻水堆 MOX 燃料形式出现的钚再循环。高杰马集团在燃料循环工业中处于领先地位。     

Discussion on refrigeration cycle for regenerative cryocoolers

Based on review and analysis of thermodynamic efficiency ε of the Carnot cycle and the cycle with two isothermal and two polytropic processes, another thermodynamic cycle with two isentropic and two polytropic processes, which can achieve the Carnot value of thermodynamic efficiency, is testified theoretically. Thermodynamic efficiency expressions of a number of ideal regenerative refrigeration cycles are derived, including the ideal pulse tube refrigeration cycle. A classified branch chart and a plot of ideal thermodynamic efficiency of regenerative refrigeration cycles are given for the purpose of comparison.     

Commercialized fast reactor cycle systems and reactor core performance of the promising fast reactors

The Feasibility Study on Commercialized Fast Reactor (FR) Cycle Systems is under progress in order to propose prominent FR cycle systems that will respond to the diverse needs of society in the future. The design studies on various FR system concepts have been achieved and then the evaluations of potential to achieve the development targets have been also carried out. Crucial development issues have been found out for each FR system concept and their development plans for the key technologies are summarized as the roadmap. As a result, it has been confirmed that the sodium-cooled FR concept is highly suited to the development targets and R&D issues are related enhancing the economy with certain perspectives for realization. A flexible and robust development program for the FR cycle system will be proposed taking account of the characteristics for each FR concept until the end of the Phase II study.     

Efficiency improvement and NOx emission reduction potentials of two‐stage turbocharged Miller cycle for stationary natural gas engines

As a part of an engine research and development project in cooperation with industry, a V20 engine is designed with two‐stage high‐pressure turbocharging, and the potential of the Miller cycle is examined through calculations using computational models based on experimental as well as computational studies. The stationary gas engines must produce less than 250 mg Nm^?3 in 5% excess of O₂, additionally the amount of NO_x emissions and their dependence on engine operational and design conditions are investigated by using a zero‐dimensional reaction kinetic model. The results show an increase in efficiency, also the amount of NO_x emissions is kept under the constraint value of 250 mg Nm^?3 for stationary engines. The results obtained here promise a very high improvement potential for future emission regulations. Copyright © 2004 John Wiley & Sons, Ltd.