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Article
Publication date: 29 April 2014

Mouna Lamnaouer, Alain Kassab, Eduardo Divo, Nolan Polley, Rodrigo Garza-Urquiza and Eric Petersen

An axisymmetric shock-tube model of the high-pressure shock-tube facility at the Texas A&M University has been developed. The shock tube is non-conventional with a non-uniform…

247

Abstract

Purpose

An axisymmetric shock-tube model of the high-pressure shock-tube facility at the Texas A&M University has been developed. The shock tube is non-conventional with a non-uniform cross-section and features a driver section with a smaller diameter than the driven section. The paper aims to discuss these issues.

Design/methodology/approach

Computations were carried out based on the finite volume approach and the AUSM+ flux-differencing scheme. The adaptive mesh refinement algorithm was applied to the time-dependent flow fields to accurately capture and resolve the shock and contact discontinuities as well as the very fine scales associated with the viscous effects. The incorporation of a conjugate heat transfer model enhanced the credibility of the results.

Findings

The shock-tube model is validated with simulation of the bifurcation phenomenon and with experimental data. The model is shown to be capable of accurately simulating the shock and expansion wave propagations and reflections as well as the flow non-uniformities behind the reflected shock wave as a result of reflected shock/boundary layer interaction or bifurcation. The pressure profiles behind the reflected shock wave agree with the experimental results.

Originality/value

This paper presents one of the first studies to model the entire flow field history of a non-uniform diameter shock tube with a conjugate heat transfer model beginning from the bursting of the diaphragm while simultaneously resolving the fine features of the reflected shock-boundary layer interaction and the post-shock region near the end-wall, at conditions useful for chemical kinetics experiments. An important discovery from this study is the possible existence of hot spots in the end-wall region that could lead to early non-homogeneous ignition events. More experimental and numerical work is needed to quantify the hot spots.

Details

International Journal of Numerical Methods for Heat & Fluid Flow, vol. 24 no. 4
Type: Research Article
ISSN: 0961-5539

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Book part
Publication date: 31 December 2010

Eric Petersen

South Africa has long been an intriguing subject of study, particularly for scholars from the United States. The intensification and dismantling of the apartheid state offers a…

Abstract

South Africa has long been an intriguing subject of study, particularly for scholars from the United States. The intensification and dismantling of the apartheid state offers a wealth of material to political scientists and social movement theorists. As the African country with the highest White population, race relations are always in the foreground, as they are in most studies of U.S. urban (and suburban) policy, while they are only just beginning to be taken as a serious ‘issue’ in European social science. U.S. scholars may occasionally look at South Africa as if it were a distorted mirror.1 Depending on one's perspective, as well as the focus of the study, South Africa can be taken as a hopeful symbol of reconciliation or as a warning of the great difficulty in overcoming decades of oppression and systemic inequality. This chapter focuses on the generally overlooked aspect of suburbanization in South Africa, which, surprisingly enough, in certain respects looks very much like U.S. suburbanization.

Details

Suburbanization in Global Society
Type: Book
ISBN: 978-0-85724-348-5

Available. Content available
Book part
Publication date: 31 December 2010

Abstract

Details

Suburbanization in Global Society
Type: Book
ISBN: 978-0-85724-348-5

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Book part
Publication date: 31 December 2010

Mark Clapson and Ray Hutchison

World population is expected to increase by some 2.6 billion from 6.9 billion in 2010 to more than 9.5 billion by mid-century. Most of this population increase will occur in the…

Abstract

World population is expected to increase by some 2.6 billion from 6.9 billion in 2010 to more than 9.5 billion by mid-century. Most of this population increase will occur in the developing nations, and most of this increase will be absorbed in the rapidly expanding metropolitan regions of these countries – the so-called megacities of the twenty-first century (United Nations, 2009). And as urban development accelerates across the globe, most of the population increase will occur in the emerging megacities and other metropolitan areas in Africa, Asia and South America. Because the original areas of settlement in the city centre have long been established, much of the population increase in these metropolitan regions will occur in the suburban areas of cities in the Global South – areas of favelas and shanty towns alongside earlier middle-class and upper-class suburbs, newly planned gated communities and garden suburbs, and indigenous models of suburban growth that will emerge in the next century.

Details

Suburbanization in Global Society
Type: Book
ISBN: 978-0-85724-348-5

Abstract

Details

The Cryopolitics of Reproduction on Ice: A New Scandinavian Ice Age
Type: Book
ISBN: 978-1-83867-043-6

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Article
Publication date: 14 August 2017

Torsten Franzke, Eric H. Grosse, Christoph H. Glock and Ralf Elbert

Order picking is one of the most costly logistics processes in warehouses. As a result, the optimization of order picking processes has received an increased attention in recent…

1673

Abstract

Purpose

Order picking is one of the most costly logistics processes in warehouses. As a result, the optimization of order picking processes has received an increased attention in recent years. One potential source for improving order picking is the reduction of picker blocking. The purpose of this paper is to investigate picker blocking under different storage assignment and order picker-route combinations and evaluate its effects on the performance of manual order picking processes.

Design/methodology/approach

This study develops an agent-based simulation model (ABS) for order picking in a rectangular warehouse. By employing an ABS, we are able to study the behaviour of individual order pickers and their interactions with the environment.

Findings

The simulation model determines shortest mean throughput times when the same routing policy is assigned to all order pickers. In addition, it evaluates the efficiency of alternative routing policies–storage assignment combinations.

Research limitations/implications

The paper implies that ABS is well-suited for further investigations in the field of picker blocking, for example, with respect to the individual behaviour of agents.

Practical implications

Based on the results of this paper, warehouse managers can choose an appropriate routing policy that best matches their storage assignment policy and the number of order pickers employed.

Originality/value

This paper is the first to comprehensively study the effects of different combinations of order picker routing and storage assignment policies on the occurrence of picker blocking.

Details

The International Journal of Logistics Management, vol. 28 no. 3
Type: Research Article
ISSN: 0957-4093

Keywords

Available. Open Access. Open Access
Article
Publication date: 9 October 2019

Chengyong Xiao, Boyana Petkova, Eric Molleman and Taco van der Vaart

Technology uncertainty poses significant challenges to manufacturers, as rapid changes in product and/or process standards and specifications can disrupt the smooth flow of…

6804

Abstract

Purpose

Technology uncertainty poses significant challenges to manufacturers, as rapid changes in product and/or process standards and specifications can disrupt the smooth flow of materials in extended supply chains. Practitioners and researchers alike who take a relational perspective widely regard supplier involvement as a potentially effective strategy to cope with technology uncertainty, as focal manufacturers can tap into their upstream supply networks for complementary resources and capabilities. However, the literature lacks a nuanced understanding of the supplier involvement processes. Specifically, the role of resource dependence for supplier involvement has yet to be systematically understood. To fill this gap, this study aims to combine the relational perspective with the resource-dependence perspective to explore how buyer dependence, supplier dependence and buyer–supplier interdependence influence buyers’ decision-making on tapping into upstream supply networks for coping with technology uncertainty.

Design/methodology/approach

To test the hypotheses, a survey is conducted among Dutch firms with more than 50 employees in the discrete manufacturing industries (ISIC 28-35), resulting in a sample of 125 manufacturers.

Findings

First, there is a significantly positive relationship between technology uncertainty and supplier involvement, giving support to the expectation that buyers are indeed involving their key suppliers in the product/process design and improvement, as a response to technology uncertainty. Second, buyer dependence and interdependence are found to be positively moderating the relationship between technology uncertainty and supplier involvement. In contrast, supplier dependence has a negative moderating effect on the baseline relationship.

Research limitations/implications

The authors contribute to a relational view on buyer–supplier relationships by showing that the validity of this view, in the context of technology uncertainty, is contingent on the resource dependence between buyers and suppliers, and the authors contribute to the supply chain management literature more generally by combining a relational perspective with a resource-dependence perspective.

Practical implications

The findings provide several nuanced insights into the effect of resource dependence (buyer dependence, supplier dependence and interdependence) on supplier involvement for coping with technology uncertainty.

Originality/value

This study contributes to the supply chain management research by going beyond the benefits of supplier involvement and highlights the circumstances under which supplier involvement is likely to occur.

Details

Supply Chain Management: An International Journal, vol. 24 no. 6
Type: Research Article
ISSN: 1359-8546

Keywords

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Article
Publication date: 3 January 2017

Kelly Boulton, Eric Pallant, Casey Bradshaw-Wilson, Beth Choate and Ian Carbone

Approximately 700 colleges and universities have committed to climate neutrality, which will require significant reductions in energy consumption. This paper aims to explore the…

551

Abstract

Purpose

Approximately 700 colleges and universities have committed to climate neutrality, which will require significant reductions in energy consumption. This paper aims to explore the effectiveness of an Annual Energy Challenge in curtailing electricity use by changing consumption behaviors at one liberal arts college.

Design/methodology/approach

From 2010 to 2014, Allegheny College (Meadville, PA, USA) ran four-week energy challenges. Electricity consumption was measured and compared to a baseline year of 2008. An alternate baseline, more granular data for 20 sub-metered buildings and historic utility bill consumption trends were further analyzed to identify any persisting change and understand the impact of behavior change separate from efficiency retrofits, changes in population and normal seasonal shifts.

Findings

Electricity consumption during the challenge period dropped an average of 9 per cent compared to the 2008 baseline and 6 per cent compared to the baseline of the 4 weeks preceding each challenge. Consumption trends changed in the years during challenge implementation compared to the years before engaging the campus community. All analyses reinforce that the challenge reduces electricity consumption. However, results must be analyzed in multiple ways to isolate for behavior change.

Practical implications

The analyses used to isolate energy challenge results due to behavior change are replicable at other institutions and would allow campuses to compare results and share proven strategies.

Originality/value

While many campuses organize energy challenges, few have published details about the results both during the challenge and continuing afterwards. Nor has a research explored the need to put results into contexts such as natural seasonal trends to isolate the impacts of behavior change.

Details

International Journal of Sustainability in Higher Education, vol. 18 no. 1
Type: Research Article
ISSN: 1467-6370

Keywords

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Book part
Publication date: 30 May 2017

Sanja Korac, Iris Saliterer and Eric Scorsone

The United States (U.S.) has been described as the root of the global financial crisis. The events of the financial, sovereign debt, and Euro crisis and the accompanying economic…

Abstract

The United States (U.S.) has been described as the root of the global financial crisis. The events of the financial, sovereign debt, and Euro crisis and the accompanying economic turmoil that have spread throughout most of the Western world have been traced back to the excessive consumer borrowing, sub-prime mortgage lending and ultimately the housing bubble in the United States. Its burst in 2008 created a shock that overshadowed prior recession and fiscal stress of governmental entities in the United States. Deriving over 90% of their own tax revenues from property taxes, local governments in Michigan have been hit even more excessively. However, the cases analysed in this chapter not only tell a unique story of deep shock and legacy costs, but also of creative ways of surviving the crisis, exerting different patterns of financial resilience. In general, state regulations restricted buffering the impact, and some cities additionally suffered from their geographical vicinity to and economic dependency on Detroit, a city that stands for the turbulence of the U.S. automobile industry. After first deploying buffering capacities that still existed, two cases saw the crisis as an opportunity to address their vulnerabilities (reactive adapters), an opportunity that was not recognised in the case of a constrained adapter. In contrast, one case showed strong anticipatory and coping capacities that have been built up in the past, equipping the local government to operate in a lean and efficient way, and to proactively adapt to arising shocks.

Details

Governmental Financial Resilience
Type: Book
ISBN: 978-1-78714-262-6

Keywords

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Book part
Publication date: 29 April 1994

Karen Markey Drabenstott and Diane Vizine-Goetz

Abstract

Details

Using Subject Headings for Online Retrieval: Theory, Practice and Potential
Type: Book
ISBN: 978-0-12221-570-4

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