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Article
Publication date: 27 May 2019

Masoud Mozaffari, Annunziata D’Orazio, Arash Karimipour, Ali Abdollahi and Mohammad Reza Safaei

The purpose of this paper is to improve the lattice Boltzmann method’s ability to simulate a microflow under constant heat flux.

Abstract

Purpose

The purpose of this paper is to improve the lattice Boltzmann method’s ability to simulate a microflow under constant heat flux.

Design/methodology/approach

Develop the thermal lattice Boltzmann method based on double population of hydrodynamic and thermal distribution functions.

Findings

The buoyancy forces, caused by gravity, can change the hydrodynamic properties of the flow. As a result, the gravity term was included in the Boltzmann equation as an external force, and the equations were rewritten under new conditions.

Originality/value

To the best of the authors’ knowledge, the current study is the first attempt to investigate mixed-convection heat transfer in an inclined microchannel in a slip flow regime.

Details

International Journal of Numerical Methods for Heat & Fluid Flow, vol. 30 no. 6
Type: Research Article
ISSN: 0961-5539

Keywords

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Article
Publication date: 25 May 2012

C.R. Leonardi, D.R.J. Owen and Y.T. Feng

The purpose of this paper is to present a novel computational framework based on the lattice Boltzmann method (LBM) and discrete element method (DEM) capable of simulating…

Abstract

Purpose

The purpose of this paper is to present a novel computational framework based on the lattice Boltzmann method (LBM) and discrete element method (DEM) capable of simulating fines migration in three dimensions. Fines migration occurs in a block cave mine, and is characterised by the faster movement of fine and often low‐grade material towards the draw point in comparison to larger, blocky material.

Design/methodology/approach

This study builds on the foundations and applications outlined in a companion paper, in which the non‐Newtonian LBM‐DEM framework is defined and applied in 2D simulations. Issues relevant to the extension to 3D, such as spatial discretisation, fluid boundary conditions and the definition of synthetic bulk material parameters using a power law model, are discussed.

Findings

The results of the 3D DEM percolation replication showed that migration is predominantly limited to within the draw zone, and that the use of a low‐cohesion material model resulted in a greater amount of fines migration. The draw sensitivity investigation undertaken with the two bell partial block cave analysis did not show a significant difference in the amount of migration, despite the two draw strategies being deliberately chosen to result in isolated and interactive draw of material.

Originality/value

Along with the companion paper, this paper presents a novel application of the developed non‐Newtonian LBM‐DEM framework in the investigation of fines migration, which until now has been limited to scale models, cellular automata or pure DEM simulations. The results highlight the potential for this approach to be applied in an industrial context, and indicate a number of potential avenues for further research.

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Article
Publication date: 25 May 2012

C.R. Leonardi, D.R.J. Owen and Y.T. Feng

The purpose of this paper is to present a novel computational framework capable of simulating the block cave phenomenon of fines migration in two dimensions. Fines…

Abstract

Purpose

The purpose of this paper is to present a novel computational framework capable of simulating the block cave phenomenon of fines migration in two dimensions. Fines migration is characterised by the faster movement of fine and often low‐grade material towards the draw point in comparison to larger, blocky material. A greater understanding of the kinematic behaviour of fines and ore within the cave during draw is integral to the solution of this problem.

Design/methodology/approach

The lattice Boltzmann method (LBM) is employed in a nonlinear form to represent the fines as a continuum, and it is coupled to the discrete element method (DEM) which is used to represent large blocks. The issues relevant to this approach, such as fluid‐solid interaction, the synchronisation of explicit schemes, and the characterisation of a bulk material as a non‐Newtonian fluid are discussed.

Findings

Results of the 2D simulations reveal migration trends for the geometries, material properties and operational sequences analysed. By executing an extensive programme of numerical experiments the influence of these and other relevant block cave factors on the migration of fines could be isolated.

Originality/value

To the authors' knowledge, this is the first time the LBM has been used to simulate the flow of bulk materials. The non‐Newtonian LBM‐DEM framework is also a novel approach to the investigation of fines migration, which until now has been limited to scale models, cellular automata or pure DEM simulations. The results of the 2D migration analyses highlight the potential for this novel approach to be applied in an industrial context and also encourage the extension of the framework to 3D.

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Book part
Publication date: 11 August 2017

Gabriela Drăgan

The chapter provides a radiography of the 2014–2020 Cohesion Policy, focusing on both main continuity and innovation elements (in terms of objectives, implementation rules…

Abstract

The chapter provides a radiography of the 2014–2020 Cohesion Policy, focusing on both main continuity and innovation elements (in terms of objectives, implementation rules and financial allocations) and on some of the likely effects of the current rules on the new European Union (EU) non-euro member countries. The closer link between EU funds and EU economic governance, which has been introduced in the current financial period, has the potential to influence negatively the evolution of the EU regional development disparities, especially in the EU eastern periphery. These new conditionalities (ex-ante and macroeconomic), whose main effects, in the case of non-compliance, would be the suspension of EU funds, might deteriorate even more the economic situation, particularly in those regions with the greatest needs in terms of infrastructure or administrative capacity. The Romanian case is particularly relevant for this debate.

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Article
Publication date: 12 June 2017

Bruce D. Jones and John R. Williams

Volume mapping of large spherical particles to a Cartesian grid with smaller grid elements is typically required in application of simple immersed boundary conditions in…

Abstract

Purpose

Volume mapping of large spherical particles to a Cartesian grid with smaller grid elements is typically required in application of simple immersed boundary conditions in coupled engineering simulations. However, there exists no unique analytical solution to computation of the volume of intersection between spheres and cubes. The purpose of this paper is to determine a suitable solution to this problem depending on the required level of accuracy.

Design/methodology/approach

In this work, existing numerical techniques for computing intersection volume are reviewed and compared in terms of accuracy and performance. In addition to this, a more efficient linear relationship is proposed and included in this comparison.

Findings

The authors find in this work that a simple linear relationship is both acceptably accurate and more computationally efficient than the contemporary techniques.

Originality/value

This simple linear approach may be applied to accurately compute solutions to fluid-particle systems with very large numbers of particles.

Details

Engineering Computations, vol. 34 no. 4
Type: Research Article
ISSN: 0264-4401

Keywords

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Article
Publication date: 2 March 2015

Deming Nie, Limin Qiu and Xiaobin Zhang

The purpose of this paper is to study the flow patterns and particle-particle collisions during the sedimentation of multiple circular particles under gravity at…

Abstract

Purpose

The purpose of this paper is to study the flow patterns and particle-particle collisions during the sedimentation of multiple circular particles under gravity at intermediate Reynolds numbers through direct numerical simulations (DNS).

Design/methodology/approach

The previously developed lattice Boltzmann-direct forcing/fictitious domain (LB-DF/FD) method is adopted in this work to conduct DNS.

Findings

It is found that the number of particle-particle collisions display a linear growth at long times after an initial evolution, resulting in a constant collision rate, which also depends the initial arrangement.

Originality/value

The problem of particle-particle collisions during sedimentation with two kinds of particle density has not been considered before and it is of special importance in various industries.

Details

International Journal of Numerical Methods for Heat & Fluid Flow, vol. 25 no. 2
Type: Research Article
ISSN: 0961-5539

Keywords

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Article
Publication date: 31 December 2006

Dian Tjondronegoro, Lei Wang and Adrien Joly

Affordable mobile devices with video playback functionality are rapidly growing in the market. Current wireless and third generation communication networks enable smoother…

Abstract

Affordable mobile devices with video playback functionality are rapidly growing in the market. Current wireless and third generation communication networks enable smoother and higher quality streaming video. With the support of these technologies, most participants in telecom value‐added service chain are planning to shift their business focus to a more profitable and appealing area, mobile TV. Previous work that survey on users' behavior while consuming mobile TV has indicated that users normally watch brief and casual contents, and not the full program. However, most of the current services adopt a “push” approach since users passively receive pre‐defined contents, rather than pulling the interesting topics and segments. In order to promote a more enjoyable and rewarding watching experience, this paper will propose a framework to support a fully interactive mobile TV. The main goal is to enable users to: 1) visually locate interesting topics across multiple genres (such as news, sports and entertainment) and 2) fully control the playback flow of the multimedia items while selecting the most interesting segments. A web‐based system has been developed to implement and test the effectiveness of the proposed framework in a wireless and mobile setting.

Details

International Journal of Web Information Systems, vol. 2 no. 3/4
Type: Research Article
ISSN: 1744-0084

Keywords

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Book part
Publication date: 12 January 2021

Michael Lounsbury, Deborah A. Anderson and Paul Spee

Volumes 70 and 71 of Research in the Sociology of Organizations combine to comprise cutting edge theory and empirical scholarship at the interface of practice and…

Abstract

Volumes 70 and 71 of Research in the Sociology of Organizations combine to comprise cutting edge theory and empirical scholarship at the interface of practice and institution in organization studies. As we highlight, this interface has spurred particularly generative conversations with many open questions, and much to explore. We provide a review of scholarly developments in practice theory and organizational institutionalism that have given rise to this interest in building a bridge between scholarly communities. As signaled by recent efforts to construct a practice-driven institutionalism, we highlight how connecting practice theory with the institutional logics perspective provides a particularly attractive focal point for scholarship at this interface due to a variety of shared ontological and epistemological commitments, including the constitution of actors and their behavior. Collectively, the papers assembled unlock exciting opportunities to connect distinct, but related scholarly communities on practice and institution, seeding scholarship that can advance our understanding of organizational and societal dynamics.

Details

On Practice and Institution: New Empirical Directions
Type: Book
ISBN: 978-1-80043-416-5

Keywords

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Book part
Publication date: 12 January 2021

Michael Lounsbury, Deborah A. Anderson and Paul Spee

Volumes 70 and 71 of Research in the Sociology of Organizations combine to comprise cutting edge theory and empirical scholarship at the interface of practice and…

Abstract

Volumes 70 and 71 of Research in the Sociology of Organizations combine to comprise cutting edge theory and empirical scholarship at the interface of practice and institution in organization studies. As we highlight, this interface has spurred particularly generative conversations with many open questions, and much to explore. We provide a review of scholarly developments in practice theory and organizational institutionalism that have given rise to this interest in building a bridge between scholarly communities. As signaled by recent efforts to construct a practice-driven institutionalism, we highlight how connecting practice theory with the institutional logics perspective provides a particularly attractive focal point for scholarship at this interface due to a variety of shared ontological and epistemological commitments, including the constitution of actors and their behavior. Collectively, the papers assembled unlock exciting opportunities to connect distinct, but related scholarly communities on practice and institution, seeding scholarship that can advance our understanding of organizational and societal dynamics.

Details

On Practice and Institution: Theorizing the Interface
Type: Book
ISBN: 978-1-80043-413-4

Keywords

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Article
Publication date: 6 February 2009

Abdelhamid Kerkadi, Abdelmonem S. Hassan and Adil Eltayeb M. Yousef

The purpose of this paper is to estimate the prevalence of the risk of overweight and overweight in Qatari children ages 9 through 11 and to compare the prevalence using…

Abstract

Purpose

The purpose of this paper is to estimate the prevalence of the risk of overweight and overweight in Qatari children ages 9 through 11 and to compare the prevalence using CDC and IOTF cut‐offs.

Design/methodology/approach

A cross‐sectional study in a randomly selected sample of 1,213 Qatari children was carried out. Weight and height were measured and BMI was calculated for all children. The risk of overweight and overweight were defined using as references both the CDC BMI percentiles for age and gender and IOTF cut‐off values.

Findings

Weight, height, and BMI increased with age and differences were significant (p<0.0001). According to the CDC and IOTF references, the overall prevalence of the risk of overweight affected 15.8 and 21.1 per cent respectively, while overweight was prevalent in 21.8 and 17.7 per cent respectively. Using either reference, the prevalence of the risk of overweight was higher among girls compared with boys (22.4 per cent, 19.4 per cent respectively), while overweight was higher among boys than among girls (20.6 per cent, 15.5 per cent respectively) but the differences were not statistically significant for both.

Originality/value

This study focused on children aged 9‐11 years, which represents a transition period between childhood and adolescence. Studying overweight in childhood is important since identification of children who may become obese adults can facilitate early intervention and avoidance of the morbidity and mortality associated with adult obesity. Limited studies on the prevalence of overweight have been conducted in Qatar.

Details

Nutrition & Food Science, vol. 39 no. 1
Type: Research Article
ISSN: 0034-6659

Keywords

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