Heat Transfer Model Performance in Simulation of Process Deviations

Performance of thermal process simulation software was tested for predicting internal product temperature and lethality. Responses were tested for process deviations on canned products with a wide range of heating characteristics for computer-based on-line control of retorts. Static and agitated processes were tested with products exhibiting heating rate factors (fh) ranging from 2 to 70 min. Cans were fitted with thermocouples and subjected to deviations of various types. Center temperature profiles and lethalities predicted by the model in response to dynamic retort temperatures were compared with those measured by thermocouples. Profiles agreed, and process lethalities calculated from predicted and measured profiles agreed ±10% with the model slightly underpredicting measured lethality.     

调峰汽轮机转子热应力及寿命损耗在线监测系统

依据调峰机组的实际运行数据，利用九节点有限单元法计算了汽轮机转子的温度应力场，确定了转子的危险截面和最大应力部位。在此基础上，修正了转子的一维热应力简化计算式，计算调峰汽轮机转子疲劳寿命损耗，建立了转子热应力及寿命损耗的线监测数学模型。并在Windows95/98操作基础上开发了转子应力监测软件。该监测系统对电厂的实际运行具有重要的指导意义。     

蒸发式空冷器的在线清洗预膜

根据蒸发式空冷器结垢状况,采用化学清洗预膜和高压水射流清洗相结合的方法,有效防止了空冷器发生二次腐蚀.保障了设备正常、安全运行.     

Pressure-induced pH changes in aqueous solutions - On-line measurement and semi-empirical modelling approach

The main aim of this work is to investigate the effect of CO₂ and N₂O under pressure in aqueous solution - both on-line and in real-time. In particular, the paper presents the kinetics of pH behaviour of either slightly buffered minimal medium (MM) or non-buffered solution (Ringer solution) during high-pressure treatment at 5, 30 and 60 bar at 25 °C.An innovative spectrophotometric approach has been developed: an optical fiber conducted the inlet signal of a light source into the high-pressure reactor, while another fiber conducted the outlet signal to a spectrometer, thus, obtaining measurements on-line and real-time.CO₂ treatment resulted in a pH decrease down to 3.0 in Ringer solution with the equilibrium being reached after 800 s, while the slightly buffered MM allows only for a decrease down to 4.5 with equilibrium being reached after slightly more than 40 s at 60 bar.N₂O treatment, as expected, did not lead to any acidification of the treated medium at any conditions tested.Furthermore, a mathematical model describing both the solubilization kinetics of CO₂ and in aqueous solution and the decrease of extracellular pH has been implemented. This model may easily be applied to different reactor configurations. The theoretical results and the goodness of the fit has been verified using the experimental results showing a good accuracy of the complex phenomena with a simplification that is of vital relevance for technical processes.     

在线案例学习国内外研究综述

在线案例学习所提供的真实的学习情境、充分的交流协作机会、有效的学习资源和灵活的学习方式,不仅可以帮助学习者将理论和实践结合,还能提高问题分析、反思等高阶能力。文章对国内外研究文献进行总结得出,对于在线案例学习的研究主要集中在案例资源的建设、案例库管理平台的开发,以及在线案例学习支持等方面。     

More than a master plan: Amman 2025

The recent plan for Amman, Jordan, combined elements of both master planning and strategic planning while pushing beyond the boundaries of both to incorporate governmental reorganization, national development concerns, and the “branding” of the city. The paper explores this deviation from traditional master planning and documents the innovations that emerged from a commitment to bring planning and implementation closer together in time and use the planning process to build planning capacity in Amman and throughout Jordan. As planners continue to negotiate between holistic visions and the pressures of development, Amman 2025 exposes the strengths and weaknesses of strategic planning and offers useful lessons.     

Electromyography applied to sport ergonomics

Abstract

The improvement of electromyographic (EMG) devices for the detection of electric potentials produced in voluntary complex movements and the evolution of methodological approaches to data acquisition and computerized analysis of patterns, are responsible for the increased applications of EMG in bioengineering, rehabilitation, sport and occupational biomechanics, physiology and zoology and to a lesser extent in ergonomics. This paper describes three different EMG applications related to a sport environment using three different EMG registration and data acquisition approaches.

The first study examined the relation between the swimming action in water and its simulation using training equipment on land. It was found that with respect to the mechanical aspects of dry-land equipment and to the biomechanical differences in the execution of the front crawl action on dry land and in water, based on EMG activity of the propulsion muscles, the best results were found when using devices with accommodating resistance. Recovery muscles were best imitated using isokinetics, but despite the greater effort on land, lower EMG activity was recorded than in water. It was generally observed that whenever the swimmer acted against a mechanical resistance an important pattern deviation was noted.

Second, a study to determine the influence of ski materials on the EMG muscle activity of skiers showed systematic differences between the use of racing, soft and compact skis. The results supported the idea that the soft ski should be more highly recommended than the compact or racing ski for both general and competive use.

Finally, in a third study we found that there was a very high degree of similarity in the pattern and intensity of muscle activity in both free swimming and swimming against a mechanical resistance (MAD swimming), even though the kinesiological aspects of the movement trajectory were proved different beforehand.     

攀钢镀锌机组连续退火炉在线控制系统

针对攀钢现有的自动化控制模式,开发出一种在线优化二级控制系统（L2）。介绍了L2系统的组成及其功能。系统在线投入后运行稳定,各项生产技术指标得到了系统的优化,极大地减少了生产过程中生产参数的人工输入。     

ZZ-89型在线灰分仪在邢台选煤厂的应用

介绍了ZZ-89型在线测灰仪的工作原理,指出传统灼烧测灰法在指导选煤生产中存在的问题,阐述了ZZ-89型在线测灰仪在邢台矿选煤厂的应用情况以及在提高经济效益和社会效益方面发挥的作用.     

PCB行业充满着挑战的年代

文章概述了在2009中国PCB工业面临的四大挑战。