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Article
Publication date: 1 February 2000

A.N. Pavlov, S.S. Sazhin, R.P. Fedorenko and M.R. Heikal

Detailed results of numerical calculations of transient, 2D incompressible flow around and in the wake of a square prism at Re = 100, 200 and 500 are presented. An

Abstract

Detailed results of numerical calculations of transient, 2D incompressible flow around and in the wake of a square prism at Re = 100, 200 and 500 are presented. An implicit finite‐difference operator‐splitting method, a version of the known SIMPLEC‐like method on a staggered grid, is described. Appropriate theoretical results are presented. The method has second‐order accuracy in space, conserving mass, momentum and kinetic energy. A new modification of the multigrid method is employed to solve the elliptic pressure problem. Calculations are performed on a sequence of spatial grids with up to 401 × 321 grid points, at sequentially halved time steps to ensure grid‐independent results. Three types of flow are shown to exist at Re = 500: a steady‐state unstable flow and two which are transient, fully periodic and asymmetric about the centre line but mirror symmetric to each other. Discrete frequency spectra of drag and lift coefficients are presented.

Details

International Journal of Numerical Methods for Heat & Fluid Flow, vol. 10 no. 1
Type: Research Article
ISSN: 0961-5539

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Article
Publication date: 5 May 2015

Sajjad Miran and Chang Hyun Sohn

– The purpose of this paper is to numerically investigate the influence of corner radius on flow past a square cylinder at a Reynolds number 500.

Abstract

Purpose

The purpose of this paper is to numerically investigate the influence of corner radius on flow past a square cylinder at a Reynolds number 500.

Design/methodology/approach

Six models were studied, for R/D=0 (square cylinder), 0.1, 0.2, 0.3, 0.4, and 0.5 (circular cylinder), where R is the corner radius and D is the characteristic dimension of the body. The transient two-dimensional (2D) laminar and large eddy simulations (LES) models were employed using finite volume code. The Strouhal number, mean drag coefficient (CD), and root mean square (RMS) value of lift coefficient (CL,RMS), for different R/D values, were computed and compared with experimental and other numerical results.

Findings

The computational results showed good agreement with previously published results for a Reynolds number, Re=500. It was found that the corner effect on a square cylinder greatly influences the flow characteristics around the cylinder. Results indicate that, as the corner radius ratio, R/D, increases, the Strouhal number increases rapidly for R/D=0-0.2, and then gradually rises between R/D=0.2 and 0.5. The minimum values of the mean drag coefficient and the RMS value of lift coefficient were found around R/D=0.2, which is verified by the time averaged streamwise velocity deficit profile.

Originality/value

On the basis of the numerical results, it is concluded that rounded corners on a square cylinder are useful in reducing the drag and lift forces generated behind a cylinder. Finally, it is suggested that with a rounded corner ratio of around R/D=0.2, the drag and oscillation of the cylinder can be greatly reduced, as compared to circular and square cylinders.

Details

International Journal of Numerical Methods for Heat & Fluid Flow, vol. 25 no. 4
Type: Research Article
ISSN: 0961-5539

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Article
Publication date: 4 January 2016

Sajjad Miran and Chang Hyun Sohn

– The purpose of this paper is to focus on the variation of wake structures and aerodynamic forces with changes in the cylinder corner radius and orientation.

Abstract

Purpose

The purpose of this paper is to focus on the variation of wake structures and aerodynamic forces with changes in the cylinder corner radius and orientation.

Design/methodology/approach

Numerical simulations were performed for flow past a square cylinder with different corner radii placed at an angle to the incoming flow. In the present study, the rounded corner ratio R/D=0 (square cylinder), 0.1, 0.2, 0.3, and 0.4 (where R is the corner radius and D is the characteristic dimension of the body) and the angle of incidence α in the range of 0°-45° were considered.

Findings

The numerical model was validated by comparing the present results with results in the available literature, and they were found to be in good agreement. The critical incidence angle for the rounded corner cylinder – corresponding to the minimum mean drag coefficient (C D ), the minimum root mean square value of the lift coefficient C L,RMS), and the maximum Strouhal number – shifted to a lower incidence angle compared with the sharp corner square cylinder. The minimum drag and lift coefficient at R/D=0 were observed for the critical incidence angle αcri=12°, whereas for R/D=0.1-0.4, the minimum drag and lift coefficient were found to be within the range of 5°-10° for α.

Originality/value

The presented results shows the importance of the incidence angle and rounded corners of the square cylinder for reduction of aerodynamic forces. The two parameters support the shear layer flow reattachment on the lateral surface of the cylinder, have a strong correlation with the reduction of the wake width, and hence reduced the values of C D and C L .

Details

International Journal of Numerical Methods for Heat & Fluid Flow, vol. 26 no. 1
Type: Research Article
ISSN: 0961-5539

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Article
Publication date: 1 June 2004

Dawn Dobni

This paper presents a framework for understanding and analyzing the productivity of service workers. Based on findings in the multidisciplinary literature, it provides a

Abstract

This paper presents a framework for understanding and analyzing the productivity of service workers. Based on findings in the multidisciplinary literature, it provides a working model for services managers that: recognizes that the definition of productivity may vary across service jobs, acknowledges that there are different levers for maximizing productivity in different contexts, and indicates that managing productivity needs to be viewed as a task for marketing, not just the organization's internal functions. The purview and implications of each component of the framework are discussed, together with some marketing‐based suggestions for productivity improvement.

Details

Journal of Services Marketing, vol. 18 no. 4
Type: Research Article
ISSN: 0887-6045

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Article
Publication date: 22 July 2014

N. Antonova

A new approach was suggested for creating nano-dimensional materials based on water-soluble polymers. Nano-seized Al-contained structures were synthesized; such structures…

Abstract

A new approach was suggested for creating nano-dimensional materials based on water-soluble polymers. Nano-seized Al-contained structures were synthesized; such structures were screened by a cover of sodium-carboxymethylcellulose by heating up to 70-80 degrees of Celsius of a sodium-carboxymethylcellulose's polymere with Al microparticles with dimension less than 20 mkm. Morphological features of created composites were researched. It was established that agglomerates of received particles were reached values of 300-600 nm and consisted of tubular types' structures with dimensions 80-100 nm.

Details

World Journal of Engineering, vol. 11 no. 3
Type: Research Article
ISSN: 1708-5284

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Article
Publication date: 27 July 2020

Dharyll Prince Abellana

This paper attempts to develop a hybrid cause and effect diagram (CED) and interpretative structural model (ISM) for root cause analysis in quality management. The…

Abstract

Purpose

This paper attempts to develop a hybrid cause and effect diagram (CED) and interpretative structural model (ISM) for root cause analysis in quality management. The proposed model overcomes the weakness of the CED in reliably articulating hierarchical cause–effect Relationships.

Design/methodology/approach

A focus group discussion (FGD) among quality experts in the case company to establish relationships between the determined causes.

Findings

The hybridization of the CED and ISM allowed the causes to be ordered more clearly to determine potential root causes as well as presenting these causes more comprehensively.

Originality/value

The paper has been one of the very few attempts to improve the CED approach. As such, this paper employs the ability of the ISM to order concepts in a hierarchical structure, which is useful in determining root causes.

Details

International Journal of Quality & Reliability Management, vol. 38 no. 3
Type: Research Article
ISSN: 0265-671X

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Book part
Publication date: 24 October 2018

Edmund Ramsden

Seeking to build an objective scientific approach to psychiatry, American psychiatrists, physiologists, and psychologists began to turn to the conditional reflex method of…

Abstract

Seeking to build an objective scientific approach to psychiatry, American psychiatrists, physiologists, and psychologists began to turn to the conditional reflex method of Ivan Pavlov from the late 1920s. The generation of “neurotic” animals in the laboratory was critical to the emergence of a new experimental psychiatry in the United States. To understand the development of this field of research, the chapter will draw first on Mary Morgan’s identification of the mediatory and intermediary role of models and their ability to surprise and generate new questions, and second, upon her recent work on narratives in science. It will argue that it was through discursive and descriptive techniques that traced over time the tangled and interconnected lives of experimental subjects, that such elements of unpredictability in the animal laboratory were transformed into tools of research and put to disciplinary uses, promoting the clinical relevance of this new objective approach to psychiatric medicine.

Details

Including a Symposium on Mary Morgan: Curiosity, Imagination, and Surprise
Type: Book
ISBN: 978-1-78756-423-7

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Article
Publication date: 1 June 2015

Lu Wang, Xiaolan Liu, Xiqun Zheng and Yinghua Tian

Building the relationship between retting termination and pectin content remained in the fiber is crucial for ensuring the identity quality of retted flax. In order to…

Abstract

Purpose

Building the relationship between retting termination and pectin content remained in the fiber is crucial for ensuring the identity quality of retted flax. In order to measure the pectin content, pectin must be removed thoroughly from the fiber. The purpose of this paper is to find the most suitable method to extract pectin from flax phloem fiber.

Design/methodology/approach

Methods of extracting pectin from fruits were employed to ensure the complete removal of pectin from flax for the first time, including extraction with ethylene diamine tetraacetic acid, hydrochloric acid and ion exchange resin. Traditional ammonium oxalate-KOH method was adopted as control. Each procedure was optimized according to the yield of pectin. A characteristic chromogenic technique for determining the exact pectin amount was used, which ensured the precise measurement of pectin extracted.

Findings

Results showed that comparing with the traditional ammonium oxalate-KOH method, methods of hydrochloric acid and ion exchange resin extract >95 percent (w/w) pectin and the extract conditions are much milder.

Originality/value

Bulk of literatures have covered the problem of how to define the quality of retted flax. But the flax industry in China still uses sensory method to check the retting termination. Connect the fiber quality with pectin content is a brand new idea. Also, the exaction method employed from fruit pectin extract is applied in flax pectin for the first time. These methods are essential for building the relationship between the pectin content and retting termination and also significant for discovering the suitable enzyme for enzyme retting.

Details

International Journal of Clothing Science and Technology, vol. 27 no. 3
Type: Research Article
ISSN: 0955-6222

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Article
Publication date: 26 October 2010

Michael Galagudza, Dmitry Korolev, Dmitry Sonin, Viktor Postnov, Garry Papayan, Ivan Uskov, Anastasia Belozertseva and Eugene Shlyakhto

Clinical outcome in patients with ischemic heart disease can be significantly improved with the implementation of targeted drug delivery into the ischemic myocardium. The…

Abstract

Purpose

Clinical outcome in patients with ischemic heart disease can be significantly improved with the implementation of targeted drug delivery into the ischemic myocardium. The purpose of this paper is to review the data of recent literature and present original findings relevant to the problem of therapeutic heart targeting with use of nanoparticles.

Design/methodology/approach

For literature review, a public‐domain database (Medline) was searched using a web‐based search engine (PubMed) and the following key words: “nanoparticles”, “nanocarriers”, and “targeted drug delivery”. Experimental approaches included fabrication of carbon and silica nanoparticles, their characterization and surface modification. The acute hemodynamic effects of nanoparticle formulation as well as nanoparticle biodistribution were studied on male Wistar rats.

Findings

Carbon and silica nanoparticles are biocompatible materials that can be used as carriers for heart‐targeted drug delivery. Concepts of passive and active targeting can be applied to the development of targeted drug delivery to the ischemic myocardial cells.

Originality/value

The present paper is believed to be the first on ligand‐directed targeted drug delivery into the damaged myocardium.

Details

Journal of Manufacturing Technology Management, vol. 21 no. 8
Type: Research Article
ISSN: 1741-038X

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Article
Publication date: 15 February 2013

George W. Blazenko and Yufen Fu

The value‐premium is the empirical observation that “value” stocks (low market/book) have higher returns than “growth” stocks (high market/book). The purpose of this paper…

Abstract

Purpose

The value‐premium is the empirical observation that “value” stocks (low market/book) have higher returns than “growth” stocks (high market/book). The purpose of this paper is to propose a new explanation for the value‐premium that the authors call the limits to growth hypothesis.

Design/methodology/approach

To guide the testing, a dynamic equity valuation model was used that has the property that profitability increases risk for value firms in anticipation of future growth‐leverage, whereas, profitability “covers” the capital expenditure costs of growth, which decreases risk for growth firms. Because the authors interpret dividends as a corporate response to growth‐limits, they test for this predicted differential relation between profitability and risk for value versus growth stocks with the returns of profitable dividend‐paying firms.

Findings

It is found that profitability increases returns to a greater extent for dividend‐paying value firms compared to dividend‐paying growth firms, which is consistent with a differential relation between profitability and risk. At the same time, it is also found that growth firms have lower returns than value firms.

Originality/value

The authors use the limits‐to‐growth hypothesis to explain why profitability can either increase or decrease risk. High‐profitability dividend‐paying growth firms have lower returns than low‐profitability dividend‐paying value firms. This value‐premium is consistent with the argument that high profitability “covers” the capital expenditure costs of growth, which decreases risk and, thus, returns. At the same time, profitability increases returns to a greater extent for value stocks compared to growth stocks, which is consistent with the hypothesis that profitability increases risk for value firms in anticipation of future growth‐leverage.

Details

Managerial Finance, vol. 39 no. 3
Type: Research Article
ISSN: 0307-4358

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