Efficient Approximation of Unsteady Friction Weighting Functions

A simple method is presented for evaluating wall shear stresses from known flow histories in unsteady pipe flows. The method builds on previous work by Trikha, but has two important differences. One of these enables the method to be used with much larger integration time steps than are acceptable with Trikha’s method. The other, a general procedure for determining approximations to weighting functions, enables it to be used at indefinitely small times (high frequencies). The method is applicable to both laminar and turbulent flows.     

A model management systems approach to manufacturing systems design

Manufacturing systems design involves the solution of a complex series of interrelated problems. This complexity will increase in the future as manufacturing practices change to meet increased global competition. Research within manufacturing systems design has mainly been focused on finding improved models for solving particular problems, or extending existing modeling techniques. This has resulted in numerous modeling tools being available to support manufacturing systems design. However, little research work has been carried out into consolidating the existing theories and models. As a result, a large body of this work has not been applied in industry.Model management has evolved as a research area which investigates methods for storing, modifying, and manipulating models. This article describes a prototype model management system for manufacturing systems design. The objective here is not to develop another decision support system for manufacturing design, but to illustrate, through the development of a prototype system, a number of key ideas of how concepts from the area of model management systems can be used to support manufacturing systems design. The prototype model management system utilizes the structured modeling framework and uses an extended version of the structured modeling language. An important aspect of the prototype model management system is the incorporation of the model development task, thus allowing the system to be easily updated and adapted. The prototype system was evaluated using a range of queueing network models for manufacturing systems design.     

ZRC – A Refinement Calculus for Z

The fact that Z is a specification language only, with no associated program development method, is a widely recognised problem. As an answer to that, we present ZRC, a refinement calculus based on Morgan's work that incorporates the Z notation and follows its style and conventions. This work builds upon existing refinement techniques for Z, but distinguishes itself mainly in that ZRC is completely formalised. In this paper, we explain how programs can be derived from Z specifications using ZRC. We present ZRC-L, the language of our calculus, and its conversion laws, which are concerned with the transformation of Z schemas into programs of this language. Moreover, we present the weakest precondition semantics of ZRC-L, which is the basis for the derivation of the laws of ZRC. More than a refinement calculus, ZRC is a theory of refinement for Z. Received July 1997 / Accepted in revised form October 1998     

基于Cult3D的交互式虚拟内耳显微解剖

Cult3D是一个实现基于普通电脑的交互式人体结构三维显示的有效平台。在对内耳结构三维数据处理的基础上，使用Cult3D Designer编辑器，采用组织事件、动作与对象的关联的编程手段实现了对内耳三维对象的复杂交互动作控制，完成基于普通电脑的交互式虚拟内耳显微解剖浏览系统。     

A Timing Assumption and Two t-Resilient Protocols for Implementing an Eventual Leader Service in Asynchronous Shared Memory Systems

This paper considers the problem of electing an eventual leader in an asynchronous shared memory system. While this problem has received a lot of attention in message-passing systems, very few solutions have been proposed for shared memory systems. As an eventual leader cannot be elected in a pure asynchronous system prone to process crashes, the paper first proposes to enrich the asynchronous system model with an additional assumption. That assumption (denoted AWB) is particularly weak. It is made up of two complementary parts. More precisely, it requires that, after some time, (1) there is a process whose write accesses to some shared variables be timely, and (2) the timers of (t−f) other processes be asymptotically well-behaved (t denotes the maximal number of processes that may crash, and f the actual number of process crashes in a run). The asymptotically well-behaved timer notion is a new notion that generalizes and weakens the traditional notion of timers whose durations are required to monotonically increase when the values they are set to increase (a timer works incorrectly when it expires at arbitrary times, i.e., independently of the value it has been set to). The paper then focuses on the design of t-resilient AWB-based eventual leader protocols. “t-resilient” means that each protocol can cope with up to t process crashes (taking t=n−1 provides wait-free protocols, i.e., protocols that can cope with any number of process failures). Two protocols are presented. The first enjoys the following noteworthy properties: after some time only the elected leader has to write the shared memory, and all but one shared variables have a bounded domain, be the execution finite or infinite. This protocol is consequently optimal with respect to the number of processes that have to write the shared memory. The second protocol guarantees that all the shared variables have a bounded domain. This is obtained at the following additional price: t+1 processes are required to forever write the shared memory. A theorem is proved which states that this price has to be paid by any protocol that elects an eventual leader in a bounded shared memory model. This second protocol is consequently optimal with respect to the number of processes that have to write in such a constrained memory model. In a very interesting way, these protocols show an inherent tradeoff relating the number of processes that have to write the shared memory and the bounded/unbounded attribute of that memory.     

Preface: Volume 70, Issue 3

This volume contains the Proceedings of the REFINE 2002 workshop. The Workshop was held in Copenhagen, Denmark on July 20 and 21, 2002, as a satellite event to FLoC'02 as an FME-affiliated workshop.Refinement is one of the cornerstones of a formal approach to software engineering. Refinement is the process of developing a more detailed design or implementation from an abstract specification through a sequence of mathematically-based steps that maintain correctness with respect to the original specification.The aim of this BCS FACS refinement workshop was to bring together people who are interested in the development of more concrete designs or executable programs from abstract specifications using formal notations, tool support for formal software development, and practical experience with formal refinement methodologies.The purpose of the workshop was to provide a forum for discussion of common ground and key differences. Topics of interest included:

• Simulation techniques

• Foundations and semantics

• Case studies (specification and verification)

• Compositional and modular reasoning

• Object-orientation

• Time

• Specification notations

• Programming models

• Verification and tool support

The workshop continued a long tradition of refinement workshops run under the auspices of the British Computer Society (BCS) FACS special interest group. Running since 1988, previous refinement workshops have been held at Cambridge, London, Bath etc.In 1998 the BCS refinement workshop was combined with the Australasian Refinement Workshop to form the International Refinement Workshop, hosted at alongside Formal Methods Pacific 1998 at The Australian National University.The papers in this volume were reviewed by a small program committee consisting of

•

John Derrick<

jd1@ukc.ac.uk

, University of Kent, UK.

•

Eerke Boiten<

eab2@ukc.ac.uk

, University of Kent, UK.

•

Jim Woodcock<

jcpw@ukc.ac.uk

, University of Kent, UK.

•

Joakim von Wright<

jockum.wright@abo.fi

, Åbo Akademi University, Finland

Additional information about the Workshop can be found at: http://www.cs.ukc.ac.uk/people/staff/eab2/refine/floc.htmlThis volume will be published as volume 70 issue 3 in the series Electronic Notes in Theoretical Computer Science (ENTCS). This series is published electronically through the facilities of Elsevier Science B.V. and its auspices. The volumes in the ENTCS series can be accessed at the URLhttp://www.elsevier.nl/locate/entcsA printed version of the current volume was distributed to the participants at the workshop in Denmark.We are very grateful to the following persons, whose help has been crucial for the success of REFINE 2002: Lars-Henrik Eriksson and Peter Lindsay of FME for their help with the organization of the Workshop as satellite event of FLoC'02 and an FME affiliated workshop; Mike Mislove, one of the Managing Editors of the ENTCS series, for his assistance with the use of the ENTCS style files. Thanks are also due to the Computing Laboratory of the University of Kent, which supplied financial support to cover the printing costs.July 24, 2002John Derrick     

蜡沉积速率的逐步回归模型

含蜡原油在管道输送过程中经常会有蜡析出,并有一部分蜡沉积到管道内壁上形成结蜡层。结蜡层对管道经济运行有一定的影响,它使管道的输送能力下降,严重时甚至会造成凝管事故,给管道运输造成很大的安全隐患。为了解决上述问题,必须研究含蜡原油管道的蜡沉积规律。针对影响蜡沉积速率的主要因素有管壁处的剪切应力,管壁处温度梯度,管壁处蜡分子浓度梯度和原油的动力粘度,在小型环道上对大庆原油进行管道蜡沉积试验,采用逐步回归的方法对实验数据作回归处理,从而建立了大庆原油蜡沉积速率模型,为进一步研究原油管道蜡沉积规律和管道优化运行奠定了基础。     

Contribution of extracellular polymeric substances from Shewanella sp. HRCR-1 biofilms to U(VI) immobilization

The goal of this study was to quantify the contribution of extracellular polymeric substances (EPS) to U(VI) immobilization by Shewanella sp. HRCR-1. Through comparison of U(VI) immobilization using cells with bound EPS (bEPS) and cells with minimal EPS, we show that (i) bEPS from Shewanella sp. HRCR-1 biofilms contribute significantly to U(VI) immobilization, especially at low initial U(VI) concentrations, through both sorption and reduction; (ii) bEPS can be considered a functional extension of the cells for U(VI) immobilization and they likely play more important roles at lower initial U(VI) concentrations; and (iii) the U(VI) reduction efficiency is dependent upon the initial U(VI) concentration and decreases at lower concentrations. To quantify the relative contributions of sorption and reduction to U(VI) immobilization by EPS fractions, we isolated loosely associated EPS (laEPS) and bEPS from Shewanella sp. HRCR-1 biofilms grown in a hollow fiber membrane biofilm reactor and tested their reactivity with U(VI). We found that, when reduced, the isolated cell-free EPS fractions could reduce U(VI). Polysaccharides in the EPS likely contributed to U(VI) sorption and dominated the reactivity of laEPS, while redox active components (e.g., outer membrane c-type cytochromes), especially in bEPS, possibly facilitated U(VI) reduction.     

Diminution of quinolizidine alkaloids,oligosaccharides and phenolic compounds from two species of Lupinus and soybean seeds by the effect of Rhizopus oligosporus

Lupinus, like Glycine max (soybean), is an ancient leguminous plant. It has been used as a food by people living around the Mediterranean Sea and in the Andean Highlands. This legume contains quinolizidine alkaloids (Qas), oligosaccharides (OGS) and phenolic compounds (PC). The objective of this study was to evaluate the effect of the growth of Rhizopus oligosporus on the levels of Qas, OGS and PC from L. mutabilis, L. campestris and G. max through tempeh elaboration. The results showed that the soaking and cooking processes of legume seeds diminished the Qas content of L. mutabilis and L. campestris by 50%, and after 48 h of fermentation these compounds decreased by more than 90% in total. OGS diminished by more than 90% in the lupin seeds. The PC content of the three seed species subjected to these processes increased their absorbance value, probably due to the enzymatic action of a fungal tannase. These results suggested that the L. mutabilis, L. campestris and G. max fermentation with R. oligosporus is an efficient method for diminishing antinutritional factors and for obtaining a product with optimal nutritional value. Copyright © 2007 Society of Chemical Industry     

快速煅烧分解石灰石对其吸收CO2和SO2的影响

在加热过程中,应用一种新型的快速加热装置——铂膜反应器,及时准确地获得样品质量和颗粒温度,来研究石灰石的煅烧分解,并对石灰石加热速率高达750℃/s下的分解反应特性,及其对分解后产生的氧化钙吸收CO2和脱硫的化学反应特性进行了研究.实验表明,在初始加热阶段,高升温速率明显阻碍了煅烧分解的进行,这对分解后的CaO吸收CO2的效果影响不大.当加热速率升高时,石灰石分解后产生的CaO吸收CO2和脱硫过程中,钙利用率显著下降.