Thierry Maré, Nicolas Galanis, Sylvie Prétot and Jacques Miriel
To determine the axial evolution of the hydrodynamic and the thermal fields for mixed convection in inclined tubes and to investigate the presence of flow reversal.
Abstract
Purpose
To determine the axial evolution of the hydrodynamic and the thermal fields for mixed convection in inclined tubes and to investigate the presence of flow reversal.
Design/methodology/approach
The elliptical, coupled, steady state, three‐dimensional governing partial differential equations for heated ascending laminar mixed convection in an inclined isothermal tube were solved numerically using a finite volume staggered grid approach.
Findings
The axial evolution of the velocity profiles and fluid temperatures show that upstream diffusion has an important effect near the inlet of the heating region. As a result, both the wall shear stress and the Nusselt number are affected upstream of the heating zone. Flow reversal occurs of GF≥9 × 105. The shape and size of the region with negative velocities depends strongly on the value of the Grashof number. The effect of the Grashof number on the axial evolution of the wall shear stress and the Nusselt number is shown to be very important in the region of developing flow.
Research limitations/implications
The results have been calculated for one Reynolds number (Re=100), a single fluid (air) and one tube inclination (45°).
Practical implications
Further results of this type can be mapped and would be useful for heat exchanger design.
Originality/value
This is the first time that flow reversal has been calculated numerically for inclined tubes. Most previous studies concern horizontal or vertical tubes and use axially parabolic equations which are easier to solve but can not calculate the flow field in the region with backflow.
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Sidi El Bécaye Maïga, Cong Tam Nguyen, Nicolas Galanis, Gilles Roy, Thierry Maré and Mickaël Coqueux
To study the hydrodynamic and thermal behaviors of a turbulent flow of nanofluids, which are composed of saturated water and Al2O3 nanoparticles at various concentrations, flowing…
Abstract
Purpose
To study the hydrodynamic and thermal behaviors of a turbulent flow of nanofluids, which are composed of saturated water and Al2O3 nanoparticles at various concentrations, flowing inside a tube submitted to a uniform wall heat flux boundary condition.
Design/methodology/approach
A numerical method based on the “control‐volume” approach was used to solve the system of non‐linear and coupled governing equations. The classical κ‐ε model was employed in order to model the turbulence, together with staggered non‐uniform grid system. The computer model, satisfactorily validated, was used to perform an extended parametric study covering wide ranges of the governing parameters. Information regarding the hydrodynamic and thermal behaviors of nanofluid flow are presented.
Findings
Numerical results show that the inclusion of nanoparticles into the base fluid has produced an augmentation of the heat transfer coefficient, which has been found to increase appreciably with an increase of particles volume concentration. Such beneficial effect appears to be more pronounced for flows with moderate to high Reynolds number. In reverse, the presence of nanoparticles has induced a rather drastic effect on the wall shear stress that has also been found to increase with the particle loading. A new correlation, Nufd=0.085 Re0.71 Pr0.35, is proposed to calculate the fully‐developed heat transfer coefficient for the nanofluid considered.
Practical implications
This study has provided an interesting insight into the nanofluid thermal behaviors in the context of a confined tube flow. The results found can be easily exploited for various practical heat transfer and thermal applications.
Originality/value
The present study is believed to be an interesting and original contribution to the knowledge of the nanofluid thermal behaviors.
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Julian Martinez-Moya, Thierry Vanelslander, María Feo-Valero and Ramón Sala-Garrido
The present research aims to develop a Terminal Competitiveness Index (TCI) applied to the container terminals located in the Hamburg – Le Havre range, which is an area…
Abstract
Purpose
The present research aims to develop a Terminal Competitiveness Index (TCI) applied to the container terminals located in the Hamburg – Le Havre range, which is an area characterised for its intense container activity. The main components of the TPCI are productivity, foreland connectivity and infrastructure.
Design/methodology/approach
To construct the index, the Benefit-of-the-Doubt and the Common Set of Weights methods in Data Envelopment Analysis are used to obtain a common weighting scheme for the evaluation of container terminals.
Findings
Results show that connectivity and terminal efficiency are the most important factors for terminal competitiveness. The TCI has identified that APM Terminals Maavslakte II (Rotterdam), ECT Delta (Rotterdam) and MPET (Antwerp) turned out with the highest competitiveness score.
Originality/value
Container terminals play a key role in today’s marketplace since they are the main infrastructure responsible for loading and unloading the containers full of intermediate and final goods. Therefore, the competitiveness of such terminals is crucial for shipping lines and importing and exporting companies, influencing their cost and schedule reliability. However, there is scarce literature studying the competitiveness of container terminals, since the focus to date has been on ports as units of analysis. The terminal-approach used allows the analysis of the competitiveness of terminals belonging to different ports, but also between those located in the same port.
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Claudia Mayordomo Zapata, Salvador Moreno Moreno and José Miguel Rojo Martínez
In this chapter, we analyse the role of women in armed Basque nationalist and separatist terrorist group Euskadi Ta Askatasuna (ETA) from a gender perspective. ETA women were…
Abstract
In this chapter, we analyse the role of women in armed Basque nationalist and separatist terrorist group Euskadi Ta Askatasuna (ETA) from a gender perspective. ETA women were essential agents in the armed conflict, but their image in the mass media and society has been very different from that of their male colleagues (Rodríguez Lara, 2017). Also, their role in the terrorist gang has described a sexually based functional specialisation. In addition, this chapter seeks to contribute to the area of feminist studies on women and political violence. Women's role in one of the most important armed nationalist groups in Europe, ETA, stands as a suitable case study to understand how the mass media (press, journalism), audiovisual content, and social representations of ETA have portrayed these women. The final conclusion of this chapter is that women were not portrayed in the same way as their male colleagues. Women of ETA were doubly penalised because they were women and because they were terrorists.
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Thierry Delecolle, Ronald G. Kamin, Beatrice Parguel and Gerry Yemen
As marketers love to teach students, differentiation must be the focal point of marketing strategy. But what happens when a firm's competitive set is shared by similar customers…
Abstract
As marketers love to teach students, differentiation must be the focal point of marketing strategy. But what happens when a firm's competitive set is shared by similar customers, perceived differentiation is weak among rivals, and loyalty is a thing of the past? This was the dilemma the French luxury jeweler Mauboussin faced: how to leverage its iconic brand to access new customers, domestically and abroad, and through new channels, while preserving the image of luxury goods founded on the myth of rarity and exclusivity? The case was designed and used for the latter portion of an international MBA marketing course and would work well in most international business courses.
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Manuel Alonso Dos Santos, Ferran Calabuig Moreno and María Huertas González-Serrano
The paper refers to the development process of corporate governance and shareholder activism in transition economies. It identifies the existing corporate governance structure as…
Abstract
The paper refers to the development process of corporate governance and shareholder activism in transition economies. It identifies the existing corporate governance structure as well as main problems analysing conflicts in Polish corporations portraying the shareholders' fight for control over the corporations. The analysis of several selected shareholder conflicts, referring particularly to the fights of dominant and minority shareholders allows to point out main shortcomings of corporate governance in transition economies. The lack of standards for corporate behaviour, the poor legal system characterized by weak enforcement of investor protection rights (law in action), the practically non‐existent shareholder litigation as well as the development stage of the shareholder activism. Finally, the paper attempts to trace the development of shareholder protection and ethical behaviour presenting the process of setting high standards for the corporate activity with the reference to transparency, the treatment of minority shareholders and the managerial accountability as well as the monitoring role of authorities carried out by Polish Securities and Exchange Commission and non‐governmental associations or business initiatives (Polish Institutes of Directors, Polish Institute for Investor Relations).
Il y a quelques années, nous avions fait un essai de regroupement des ressources touristiques à partir des éléments d'attraction qui motivent le déplacement du voyageur et…
Abstract
Il y a quelques années, nous avions fait un essai de regroupement des ressources touristiques à partir des éléments d'attraction qui motivent le déplacement du voyageur et indépendamment des facteurs qui pouvaient influencer son propre esprit. Il nous était apparu que toutes les ressources disponibles quelle que soit leur situation dans le Monde pouvaient se regrouper en 4 ensembles que nous avions intitulés Lithôme (les monuments), Phytôme (la Nature), Hydrôme (l'attirance de l'eau) et Anthropôme (les activités humaines).