Application of CFD in vacuum dezincing process

Most lead bullion is refined by pyrometallurgical methods - this involves a serics of processes that remove the antimony (softening) silver (Parkes process), zinc (vacuum dezincing) and if need be, bismuth (Betterton-Kroll process). The first step, softening, removes the antimony, arsenic and tin by air oxidation in a furnace or by the Harris process. Next, in the Parkes process, zinc is added to the melt to remove the silver and gold. Insoluble zinc, silver and gold compounds are skimmed off from the melt surface. Excess zinc added during desilvering is removed from lead bullion using one of ghree methods: * Vacuum dezincing; * Chlorine dezincing; or * Harris dezincing. The present study concentrates on the Vacuum dezincing process for lead refining. The main aims of the research are to develop mathematical model(s), using Computational Fluid Dyanmics (CFD) a Surface Averaged Model (SAM), to predict the process behaviour under various operating conditions, thus providing detailed information of the process - insight into its reaction to changes of key operating parameters. Finally, the model will be used to optimise the process in terms of initial feed concentration, temperature, vacuum height cooling rate, etc.

Combined vertex-based - cell-centred finite volume method for flows in complex geometries

CFD modelling of 'real-life' processes often requires solutions in complex three dimensional geometries, which can often result in meshes where aspects of it are badly distorted. Cell-centred finite volume methods, typical of most commercial CFD tools, are computationally efficient, but can lead to convergence problems on meshes which feature cells with high non-orthogonal shapes. The vertex-based finite volume method handles distorted meshes with relative ease, but is computationally expensive. A combined vertex-based - cell-centred (VB-CC) technique, detailed in this paper, allows solutions on distorted meshes that defeat purely cell-centred physical models to be employed in the solution of other transported quantities. The VB-CC method is validated with benchmark solutions for thermally driven flow and turbulent flow. An early application of this hybrid technique is to three-dimensional flow over an aircraft wing, although it is planned to use it in a wide variety of processing applications in the future.

Computational modelling of bubbles, droplets and particles in metals reduction and refining

The CFD modelling of metals reduction processes particularly always seems to involve the interaction of liquid metals, a gas (often air) top space, liquid droplets in the top space and injection of both solid particles and gaseous bubbles into the bath. These phases all interact and exhange mass, momentum and energy. Often it is the extent to which these multi-phase phemomena can be effectively captured within the CFD model which determines whether or not a tool of genuine use to the target industry sector can constructed. In this paper we discuss these issues in the context of two problems - one involving the injection of sparging gases into a steel continuous caster and the other based on the development of a novel process for aluminium electrolysis.

Dizzy heights and occupiers' liability

Reviews case law on the occupier's duty of care to trespassers under the Occupiers' Liability Act 1984 s.1, including the issues that apply where the trespasser engaged in risky behaviour, was a child, and where the property was inherently dangerous.

Joint ownership and beneficial entitlement: Stack v Dowden.

Explores the issue of the share of beneficial entitlement to the family home where the legal title is jointly owned, but where there has not been an express declaration of a beneficial joint tenancy. Discusses the House of Lords judgment in Stack v Dowden which addressed this point. Explains how the judges moved the focus away from the court imposing its own sense of fairness on the parties or imputing an intention based on the circumstances to one where the concentration will be on the parties' relevant conduct. Outlines three other points of interest referred to in the judgment: (1) whether an indirect financial contribution could support a constructive trust; (2) whether proprietary estoppel and common intention constructive trusts should be assimilated; and (3) whether a mortgage liability is equivalent to a financial contribution.

Heavy cultural industries

The present recession has prompted scholarly and journalistic questioning of the contributions of the cultural industries to the economy. The talent-rich metropolitan clusters of London and New York are well-placed to ride out a thoroughgoing shakeup of the media markets if they manage their infrastructure, space and resources strategically, as Richard Florida has recently argued. This seems to be the assumption behind the recent Digital Britain interim report, and Gordon Brown's remarks that a digital revolution "lies at the heart" of Britain's economic recovery and that broadband and the media industry can play a leading role in pulling the UK out of the recession. Focusing on the Digital Britain report and consultation documents, this presentation seeks to unpack some of the fundamental assumptions behind this link between digital infrastructure, creativity and profitability. In particular the implicit notion of an engaged audience of users, generating "content" as well as shaping new media platforms calls into question longheld theoretical constructions of the mass audience of consumers as spectators. [From the Author]

A price worth paying?: Women and work – choice, constraint or satisficing

Purpose – Are women held back or holding back? Do women choose their jobs/careers or are they structurally or normatively constrained? The purpose of this paper is to shed fresh light on these questions and contribute to an on-going debate that has essentially focused on the extent to which part-time work is women’s choice, the role of structural and organisational constraints and the role of men in excluding women. Design/methodology/approach – The paper uses data from interviews with 80 working women – both full-time and part-time – performing diverse work roles in a range of organisations in the south east of England. Findings – It was found that many women do not make strategic job choices, rather they often ‘‘fall into’’ jobs that happen to be available to them. Some would not have aspired to their present jobs without male encouragement; many report incidents of male exclusion; and virtually all either know or suspect that they are paid less than comparable men. Those working reduced hours enjoy that facility, yet they are aware that reduced hours and senior roles are seen as incompatible. In short, they recognise both the positive and negative aspects of their jobs, whether they work full or part-time, whether they work in male-dominated or female-dominated occupations, and whatever their position in the organisational hierarchy. Accordingly, the paper argues that the concept of ‘‘satisficing’’, i.e. a decision which is good enough but not optimal, is a more appropriate way to view women’s working lives than are either choice or constraint theories. Originality/value – There is an ongoing, and often polarised, debate between those who maintain that women choose whether to give preference to work or home/family and others who maintain that women, far from being self-determining actors, are constrained structurally and normatively. Rather than supporting these choice or constraint theories, this paper argues that ‘‘satisficing’’ is a more appropriate and nuanced concept to explain women’s working lives.

Urban labour, voice and legitimacy: economic development and the emergence of community unionism

Community unionism has emerged in the past decade as a growing strand of industrial relations research and is influencing trade union strategies for renewal. This article seeks to further develop the concept, while exploring the potential roles for unions in communities subject to projects of urban regeneration.

A clear direction

Comments on the House of Lords decision in Thorner v Curtis, also referred to as Thorner v Major, on whether an unpaid farm labourer could rely on assurances made by the farmer that he would inherit the farm, to establish proprietary estoppel when the farmer died intestate. Considers whether the assurances had been clear and whether the property to be inherited could be specifically identified. Notes the Lords' consideration of the possible existence of a constructive trust. [From Legal Journals Index]

Estoppe right there

Examines the House of Lords judgment in Cobbe v Yeoman's Row Management Ltd on whether an experienced property developer was entitled to relief on the basis of proprietary estoppel for the cost of obtaining planning permission to demolish an existing property and build new houses under a non-binding oral agreement. Sets out two requisite conditions needed when deciding whether estoppel existed. Considers whether unconscionability was a separate element in making a claim for proprietary estoppel. [From Legal Journals Index]

Rights for cohabitants

Reviews the guidance given by the House of Lords in Stack v Dowden on quantifying the beneficial interests of cohabiting parties in their former family home when one party seeks to rebut the presumption of joint beneficial ownership. Comments on the subsequent application of the principles by the county court in Adekunle v Ritchie and by the Privy Council in Abbott v Abbott, highlighting the approaches used to establish an equitable interest and to quantify the parties' shares in the properties. Considers whether statutory intervention is now needed to resolve the difficulties. [From Legal Journals Index]

Sole agency vs multi-agency: An investigation of agency practice across England and Wales

Purpose: The purpose of this paper is to investigate the impact of different agency practice on agency fees, business efficiency, and housing market liquidity. Design/methodology/approach: The paper studies the effect of sole and multiple agency practices on estate agent efficiency, housing market liquidity, and commission fee levels. The analysis uses the survey data from 2000 to 2006 to investigate the different agency practices across England and Wales and their effect on estate agency business efficiency, housing market liquidity, selling price, and fee levels. Findings: The empirical analysis confirms that agency practice has a locality bias, that is, some regions are more likely to adopt sole agency practice than other regions. The estate agents with a sole agency practice charge a lower agency fee, help clients to achieve better selling price and are more efficient; whereas multiple agency practice facilitates liquidity in the housing market, but experiences higher fall-through rate. Research limitations/implications: The research focuses on estate agent rather than consumers due to the limitation of the data based on a research project concerning transaction costs designed prior to this analysis. Originality/value: There is little other research that investigates the residential estate agency practice and its impact on housing market in the past three decades in England and Wales. The findings are a useful guide for practitioners to better understand the issues associated with different agency practices and should enhance business efficiency and performance.

Heavy cultural industries

The present recession has prompted scholarly and journalistic questioning of the contributions of the cultural industries to the economy. The talent-rich metropolitan clusters of London and New York are well-placed to ride out a thoroughgoing shakeup of the media markets if they manage their infrastructure, space and resources strategically, as Richard Florida has recently argued. This seems to be the assumption behind the recent Digital Britain interim report, and the prime minister's remarks that a digital revolution "lies at the heart" of Britain's economic recovery and that broadband and the media industry can play a leading role in pulling the UK out of the recession. Focusing on the Digital Britain interim report, this presentation seeks to clarify some of the fundamental assumptions behind this link between digital infrastructure, creativity and profitability. [From the Author]