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Handbook of Transport Modelling
Type: Book
ISBN: 978-0-08-045376-7

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Book part
Publication date: 14 September 2007

Abstract

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Handbook of Transport Modelling
Type: Book
ISBN: 978-0-08-045376-7

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Article
Publication date: 1 June 1953

J. Kestin and S.K. Zaremba

The paper discusses the types of singular points occurring in the first‐order ordinary differential equation which describes compressible viscous flow in a channel or…

Abstract

The paper discusses the types of singular points occurring in the first‐order ordinary differential equation which describes compressible viscous flow in a channel or stream tube of varying cross‐sectional area. The treatment is one‐dimensional, viscosity being allowed for by assuming a tangential stress acting on the circumference. The resulting patterns of the integral curves arc examined. It is shown that for convergent‐divergent channels whose profile has no point of inflexion, the singular point is a saddle point, as is the case in frictionlcss flow. However, the sonic section or the section of highest or lowest Mach number do not coincide with the throat but arc situated downstream of it in the divergent portion. The slopes of the integral curves which pass through the sonic section arc evaluated. When the convergent‐divergent channel has a point of inflexion in its profile there may be two singular points, the first being a saddle point and the second cither a spiral point or a nodal point. It is shown that spiral points are more likely to occur than nodal points and that, when they occur, there is no radical change in the Mach number variation along the channel due to friction. On the other hand, the existence of a nodal point admits the possibility of a continuous transition from supersonic to subsonic How in which the Mach number at exit may vary within certain limits, the Mach number in the second sonic section remaining always equal to unity. In all types of flow there arc portions of the channel over which the influence of friction outweighs that of area change.

Details

Aircraft Engineering and Aerospace Technology, vol. 25 no. 6
Type: Research Article
ISSN: 0002-2667

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Article
Publication date: 1 December 1950

J. Kestin

IN the preliminary calculation for the design of a gas turbine or turbocompressor it is necessary to assume a value of the reheat factor R. The contemporary development of…

Abstract

IN the preliminary calculation for the design of a gas turbine or turbocompressor it is necessary to assume a value of the reheat factor R. The contemporary development of gas turbines and rotary compressors has aroused renewed interest in this quantity, which was studied earlier in connexion with steam turbines (refs. 1, 2, 7, 8 and 9). The paper contains an analysis of this value for a gaseous working fluid under appropriate assumptions; it is first calculated for an infinite number of stages with constant and variable specific heats; secondly, exact and approximate formulae are derived for finite numbers of stages of expansion and compression respectively and a method of estimating the heat recovery in turbines for working fluids with variable specific heats is indicated. Similar problems were considered in ref. 10 and the subject matter of Part III was presented to the Aeronautical Research Council (ref. 6).

Details

Aircraft Engineering and Aerospace Technology, vol. 22 no. 12
Type: Research Article
ISSN: 0002-2667

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Book part
Publication date: 7 August 2017

Peer Smets

This chapter aims at providing insight into how social mixing plays out in the Transvaal neighborhood in Amsterdam — a neighborhood which has gone through various rounds…

Abstract

Purpose

This chapter aims at providing insight into how social mixing plays out in the Transvaal neighborhood in Amsterdam — a neighborhood which has gone through various rounds of urban renewal — in the context of nationwide polarization between native-Dutch and Moroccan-Dutch.

Methodology/approach

This chapter is based on research with a neighborhood focus — daily interactions, urban renewal, and use of public space — which took place during 2007–2010. Methods used include participant observation, semistructured interviews, and focus groups.

Findings

The physical renewal implies renovating and pulling down social housing, and building new social or owner-occupier housing. This study provides insight into how residents of different ethnic and income backgrounds live together in the neighborhood, also taking into account the impact of social polarization at the national level.

Social implications

By knowing how people with different ethnic and class backgrounds live together in Transvaal neighborhood, it contributes to the formulation of evidence-based policies for the improvement of social cohesion, livability, safety of the neighborhood, and social capital of local residents.

Originality/value

This study looks at social mix in the context of national-level social polarization between native-Dutch and Moroccan-Dutch. This creates a new viewpoint seen against how the general literature on renewal and social mixing tends to do two things: firstly it usually explicitly or implicitly is also a tenure mix strategy, and secondly the policy focus of the social mix is usually around class issues, that is, the mixing of poor social housing tenants with richer owners.

Details

Social Housing and Urban Renewal
Type: Book
ISBN: 978-1-78714-124-7

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Article
Publication date: 16 February 2010

Joan F. Marques

This article aims to introduce practical based criteria for effective organizational communication.

Abstract

Purpose

This article aims to introduce practical based criteria for effective organizational communication.

Design/methodology/approach

The subject scope for this article is corporate communication. The study is based on literature reviews and a qualitative study, entailing the basic principles of the phenomenological approach, with 20 subjects.

Findings

Four additional criteria for effective corporate communication surfaced: responsible; professional; concise; and sincere.

Research limitations/implications

The studies reviewed, although in‐depth, apply to a small sample in one metropolitan environment, which makes generalization among different cultures riskier.

Practical implications

Organizational managers may use these findings to reflect on their communication strategies and improve them, where necessary, on the basis of the findings of this study.

Originality/value

The paper's value lies in the four additional criteria found as a result of reflections from members of the corporate workforce, after having been exposed to a course on organizational communication, and therefore, existing criteria in literature. The additional criteria may be considered important for corporate workers, and should therefore not be ignored by managers.

Details

Journal of Communication Management, vol. 14 no. 1
Type: Research Article
ISSN: 1363-254X

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Article
Publication date: 1 January 2009

X.Q. Zhang

widely‐used hypoelastic model for four well‐known objective stress rates under a four‐phase stress cycle associated with axial tension and/or torsion of thin‐walled…

Abstract

widely‐used hypoelastic model for four well‐known objective stress rates under a four‐phase stress cycle associated with axial tension and/or torsion of thin‐walled cylindrical tubes. Here, two kinds of models based upon the Cauchy stress and the Kirchhoff stress will be treated. The reduced systems of differential equations of these rate constitutive equations are derived and studied for Jaumann, Green‐ Naghdi, logarithmic and Truesdell stress rates, separately. Analytical solutions in some cases and numerical solutions in all cases are obtained using these reduced systems. Comparisons between the residual deformations are made for different cases. It may be seen that only the logarithmic stress rate results in no residual deformation. In particular, results indicate that Green‐Naghdi rate would generate unexpected residual deformation effect that is essentially different from that resulting from Jaumann rate. On the other hand, it is realized that this study accomplishes an alternative, direct proof for the nonintegrability problem of Truesdell’s hypoelastic rate equation with classical stress rates. This problem has been first treated successfully by Simo and Pister in 1984 using Bernstein’s integrability conditions. However, such treatment needs to cope with a coupled system of nonlinear partial differential equations in Cauchy stress. Here, a different idea is used. It is noted that every integrable hypoelastic equation is just an equivalent rate form of an elastic equation and hence should produce no residual deformations under every possible stress cycle. Accordingly, a hypoelastic model with a stress rate has to be non‐integrable, whenever a stress cycle can be found under which this model generates residual deformation. According to this idea of reductio ad absurdum, a well‐designed stress cycle is introduced and the corresponding residual deformations are calculated. Unlike the treatment of Bernstein’s integrability conditions, it may be a simple and straightforward matter to calculate the final deformations for a given stress cycle. This has been done in this study for several well‐known stress rates.

Details

Multidiscipline Modeling in Materials and Structures, vol. 5 no. 1
Type: Research Article
ISSN: 1573-6105

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Article
Publication date: 28 April 2020

Syed Alamdar Ali Shah, Raditya Sukmana and Bayu Arie Fianto

The purpose of this research is to propose a framework for research on Macaulay duration and establish future research directions.

Abstract

Purpose

The purpose of this research is to propose a framework for research on Macaulay duration and establish future research directions.

Design/methodology/approach

Thematic, bibliometric and content analyses have been used to review 168 research papers published between 1938 and 2019 taken from ISI Web of Science and Scopus contributed by leading authors, journals and regulatory bodies.

Findings

Identification and integration of themes of duration theory, duration model development and duration model implementation leading to unattended research gaps, and framework for research on Macaulay duration.

Research limitations/implications

The study is based on an extensive review of the literature to extract important themes, research gaps and frameworks. It does not empirically investigate significance of Macaulay duration and various sectors.

Practical implications

This research has several aspects that are helpful for practitioners. Macaulay duration has been the subject of empirical research only without any guiding framework. This research provides a platform to initiate profound researches in various areas of finance. Various proposed models are required to be tested under holistic approach in conventional and emerging fields, especially in Islamic settings.

Originality/value

This research highlights, research themes leading to framework, research gaps and factors that are crucial in developing, extending and testing duration models leading to enhancement of theoretical base of Macaulay duration.

Details

Journal of Economic Studies, vol. 48 no. 1
Type: Research Article
ISSN: 0144-3585

Keywords

Content available
Article
Publication date: 15 June 2021

David M. Herold, Katarzyna Nowicka, Aneta Pluta-Zaremba and Sebastian Kummer

The purpose of this paper is to provide new insights into the reactions and lessons learned with regard to the COVID-19 pandemic in terms of how logistics service…

Abstract

Purpose

The purpose of this paper is to provide new insights into the reactions and lessons learned with regard to the COVID-19 pandemic in terms of how logistics service providers (LSPs) managed to maintain supply chains resilience and what focus areas have been changed to keep operations functional and uphold financial stability.

Design/methodology/approach

Based on data-gathering techniques in interpretive research this study collected primary data via semi-structured interviews, interviewing informants from selected LSPs that operate on a global scale.

Findings

The results show that LSPs have built their reactions and actions to the COVID-19 outbreak around five main themes: “create revenue streams,” “enhance operational transport flexibility,” “enforce digitalization and data management,” “optimize logistics infrastructure” and “optimize personnel capacity.” These pillars build the foundation to LSP resilience that enables supply chains to stay resilient during an external shock of high impact and low probability.

Originality/value

The results of this study provide insights into how LSPs have managed the downsides and found innovative ways to overcome operational and financial challenges during the COVID-19 outbreak. As one of the first studies that specially focuses on the role of LSPs during the COVID-19 pandemic, this study categorizes the LSPs’ reactions and provides a “lessons learned” framework from a managerial perspective. From a theoretical perspective, this paper discusses the strategic role of LSPs in supply chain management and thereby extends current supply chain literature with a focus on LSP resilience.

Details

Supply Chain Management: An International Journal, vol. ahead-of-print no. ahead-of-print
Type: Research Article
ISSN: 1359-8546

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Book part
Publication date: 25 May 2021

Mustafa Oğuz

On March 11, 2020, the World Health Organization declared the COVID-19 outbreak a global pandemic. The policy responses to this outbreak have caused many impacts on our…

Abstract

On March 11, 2020, the World Health Organization declared the COVID-19 outbreak a global pandemic. The policy responses to this outbreak have caused many impacts on our daily life and economic activities around the world. Also, this outbreak has affected financial reporting practices of the firms. Thorough financial reporting in such uncertain times plays an essential role in providing qualitative financial information. It is very important for a firm to increase transparency and report on the impacts of possible risks in times of uncertainty. Furthermore, stock markets may react to COVID-19 as they have already responded to major events like disasters, news, environmental and political events. This study investigates whether and how firms’ providing information about COVID-19 pandemic in their financial reports plays a role in explaining the stock market reactions. For this, annual reports of companies included in BIST-100 index in Turkey is used to analyze the capacity for detecting risks early and determine whether there is an association between early reporting about COVID-19 and the stock risk.

Details

Contemporary Issues in Social Science
Type: Book
ISBN: 978-1-80043-931-3

Keywords

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