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Article
Publication date: 1 November 2011

Rhodri Bevan, P. Nithiarasu, Igor Sazonov, Raoul van Loon, Heyman Luckraz, Michael Collins and Andrew Garnham

The purpose of this paper is to numerically study blood flow through a subject‐specific carotid artery with a moderately severe stenosis, also to thoroughly analyse the wall shear…

261

Abstract

Purpose

The purpose of this paper is to numerically study blood flow through a subject‐specific carotid artery with a moderately severe stenosis, also to thoroughly analyse the wall shear stress (WSS), oscillatory shear index (OSI) and WSS angular deviation (WSSAD). One of the important aspects of this study is the investigation on the influence of the extensions attached to the domain outlets.

Design/methodology/approach

The segmentation of the carotid artery is carried out using a deformable model based on a level set method. A geometric potential force (GPF) is employed to deform the level set to obtain the carotid artery geometry. The initial surface meshing is generated using an advanced marching cubes (MC) method, before improving the quality of the surface mesh via a number of mesh cosmetic steps. The volume mesh generation has two parts. In the first part, a quasi‐structured, boundary layer mesh is generated in the vicinity of the geometry walls. The second part of the meshing involves unstructured tetrahedral meshing of the inner part of the geometry. After the meshing stage, the flow boundary conditions are generated by numerically solving the Helmholtz equation in both space and time. Finally, the explicit characteristic‐based split (CBS) method is employed in a parallel environment to produce a detailed analysis of wall quantities.

Findings

In general, WSS is very high in the vicinity of the carotid artery apex and in the proximity of the stenosis. From the results obtained, it is clear that the influence of outlet domain extension is marginal. While the peak instantaneous WSS differs by a maximum of 5.7 per cent, the time‐averaged WSS difference due to extended domain is only 1.3 per cent. Two other derived parameters are also examined in the paper, the oscillating shear index and the WSSAD. Both these quantities also display minor or negligible differences due to domain extension.

Originality/value

It has been perceived that domain extension is essential to avoid wrong application of boundary conditions. The results obtained, however, conclusively show that the outlet domain extension has only a moderate influence on WSS. Thus, outlet extension to the domains may not be essential for arterial blood flows. It is also observed that the dramatic values of peak WSS obtained near the stenosis is the result of high resolution mesh along with boundary layers used in this study. Both the outcomes represent the originality of this paper.

Details

International Journal of Numerical Methods for Heat & Fluid Flow, vol. 21 no. 8
Type: Research Article
ISSN: 0961-5539

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Article
Publication date: 1 August 1999

Andrew Calabrese

The prospect that technological and social innovation in the use of communication and information technologies are bringing about an end to sovereignty has been a source of…

1402

Abstract

The prospect that technological and social innovation in the use of communication and information technologies are bringing about an end to sovereignty has been a source of optimism, pessimism and ambivalence. It has captured the popular imagination and it can be found in the anxieties of national leaders about the mingling and collision of cultures and cultural products within and across their borders, and about growing awareness that environmental threats bow to no flag. According to much of this discourse, national governments are becoming increasingly powerless in their battles against real or imagined plights of cultural imperialism (and sub‐imperialism, that is, cultural imperialism within states) and capital mobility, as well as in their efforts to effectively exercise political control through surveillance and censorship. The end of sovereignty is a theme in political discussions about new pressures brought on by global regimes of trade and investment, and by unprecedented levels of global criminal networks for drug trafficking, money laundering and trade in human flesh. Social movements and non‐governmental organizations (NGOs) have reflected this by recognizing the need to match the scale of the problems they confront with appropriately scaled collective action. This article examines the discourse about the end of sovereignty and therise of new institutions of global governance. Particular emphasis is given to how advancements in the means of communication have produced the ambivalent outcomes of threatening the democratic governance of sovereign states, and serving as foundations for the assertion of democratic rights and popular sovereignty on a global scale.

Details

info, vol. 1 no. 4
Type: Research Article
ISSN: 1463-6697

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Book part
Publication date: 30 November 2023

Athina Karatzogianni and Jacob Matthews

Abstract

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Fractal Leadership
Type: Book
ISBN: 978-1-83797-108-4

Available. Content available
651

Abstract

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Information Technology & People, vol. 17 no. 3
Type: Research Article
ISSN: 0959-3845

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Article
Publication date: 1 July 1924

OUR readers will, we trust, appreciate our double souvenir number issued in connection with the Library Association Conference at Glasgow. Special features are the articles on the…

45

Abstract

OUR readers will, we trust, appreciate our double souvenir number issued in connection with the Library Association Conference at Glasgow. Special features are the articles on the Mitchell Library, Glasgow, 1874–1924, by a member of the staff, Mr. J. Dunlop, and one on the Burns Country, by Mr. J. M. Leighton, of Greenock Public Library. We printed the provisional programme in our July issue and as we go to press have little to add to the particulars there given, except to compliment the Library Association and the Local Reception Committee on the excellent programme arranged for the occasion, from both the professional and social point of view.

Details

New Library World, vol. 27 no. 2
Type: Research Article
ISSN: 0307-4803

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Article
Publication date: 1 June 1997

Eric Magnuson

Approaches to the sociology of culture have largely been constituted around the long tradition of functionalism in sociology. This has hampered the field greatly. Among other…

180

Abstract

Approaches to the sociology of culture have largely been constituted around the long tradition of functionalism in sociology. This has hampered the field greatly. Among other shortcomings, this intellectual foundation has led to a limited understanding of ideology and civil society, a conservative political orientation and an overdeterministic view of social action and the actor. In this paper, I explore and then apply a new approach to the sociology of culture, one that attempts to conceptualize more robustly the dynamics of ideology, ideological conflict and civil society. As part of this project, I endeavor to map out a critical cultural perspective that establishes a multidimensional understanding of the contingency of social action.

Details

International Journal of Sociology and Social Policy, vol. 17 no. 6
Type: Research Article
ISSN: 0144-333X

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Book part
Publication date: 24 June 2024

Noel Scott, Brent Moyle, Ana Cláudia Campos, Liubov Skavronskaya and Biqiang Liu

Free Access. Free Access

Abstract

Details

Cognitive Psychology and Tourism
Type: Book
ISBN: 978-1-80262-579-0

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Book part
Publication date: 30 November 2023

Athina Karatzogianni and Jacob Matthews

Abstract

Details

Fractal Leadership
Type: Book
ISBN: 978-1-83797-108-4

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Book part
Publication date: 10 September 2018

Nikos Smyrnaios

Abstract

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Internet Oligopoly
Type: Book
ISBN: 978-1-78769-197-1

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Article
Publication date: 1 January 1933

THE article which we publish from the pen of Mr. L. Stanley Jast is the first of many which we hope will come from his pen, now that he has release from regular library duties…

63

Abstract

THE article which we publish from the pen of Mr. L. Stanley Jast is the first of many which we hope will come from his pen, now that he has release from regular library duties. Anything that Mr. Jast has to say is said with originality even if the subject is not original; his quality has always been to give an independent and novel twist to almost everything he touches. We think our readers will find this to be so when he touches the important question of “The Library and Leisure.”

Details

New Library World, vol. 35 no. 9
Type: Research Article
ISSN: 0307-4803

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