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Article
Publication date: 4 December 2018

Alireza Rahimi, Ali Dehghan Saee, Abbas Kasaeipoor and Emad Hasani Malekshah

The purpose of this paper is to carry out a comprehensive review of some latest studies devoted to natural convection phenomenon in the enclosures because of its significant…

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Abstract

Purpose

The purpose of this paper is to carry out a comprehensive review of some latest studies devoted to natural convection phenomenon in the enclosures because of its significant industrial applications.

Design/methodology/approach

Geometries of the enclosures have considerable influences on the heat transfer which will be important in energy consumption. The most useful geometries in engineering fields are treated in this literature, and their effects on the fluid flow and heat transfer are presented.

Findings

A great variety of geometries included with different physical and thermal boundary conditions, heat sources and fluid/nanofluid media are analyzed. Moreover, the results of different types of methods including experimental, analytical and numerical are obtained. Different natures of natural convection phenomenon including laminar, steady-state and transient, turbulent are covered. Overall, the present review enhances the insight of researchers into choosing the best geometry for thermal process.

Originality/value

A comprehensive review on the most practical geometries in the industrial application is performed.

Details

International Journal of Numerical Methods for Heat & Fluid Flow, vol. 29 no. 3
Type: Research Article
ISSN: 0961-5539

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Article
Publication date: 16 October 2018

Alireza Rahimi, Hesam Bakhshi, Ali Dehghan Saee, Abbas Kasaeipoor and Emad Hasani Malekshah

The study aims to study the nanofluid flow and heat transfer in a T-shaped heat exchanger. For the numerical simulations, the lattice Boltzmann method is used.

218

Abstract

Purpose

The study aims to study the nanofluid flow and heat transfer in a T-shaped heat exchanger. For the numerical simulations, the lattice Boltzmann method is used.

Design/methodology/approach

The end of each branch of the heat exchanger is considered a curve wall that requires special thermal and physical boundary conditions. To improve the thermal performance of the heat exchanger, the CuO–water nanofluid, which has better heat transfer performance with respect to pure water, is used. The dynamic viscosity of nanofluid is estimated by means of KKL model. Several active fins and solid bodies are implanted within the heat exchanger with different thermal arrangements.

Findings

In the present work, different approaches such as heatline visualization, local and total entropy generation analysis, local and total Nusselt variation are used to detect the impact of different considered parameters such as Rayleigh number (103 < Ra < 106), solid volume fraction of nanofluid (φ = 0,0.01,0.02,0.03 and 0.04 vol. per cent) and thermal arrangements of internal bodies (Case A, Case B, Case C and Case D) on the fluid flow and heat transfer performance.

Originality/value

The originality of this work is to analyze the two-dimensional natural convection and entropy generation using lattice Boltzmann method.

Details

International Journal of Numerical Methods for Heat & Fluid Flow, vol. 29 no. 1
Type: Research Article
ISSN: 0961-5539

Keywords

Available. Content available
Book part
Publication date: 14 December 2023

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Abstract

Details

Digitisation, AI and Algorithms in African Journalism and Media Contexts
Type: Book
ISBN: 978-1-80455-135-6

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Article
Publication date: 7 January 2014

Ali Dehghan, John Dugger, David Dobrzykowski and Anne Balazs

In this paper, a model of student loyalty with graduate online programs utilizing relationship marketing theory elements was developed. The relationships between service quality…

1598

Abstract

Purpose

In this paper, a model of student loyalty with graduate online programs utilizing relationship marketing theory elements was developed. The relationships between service quality, commitment and satisfaction, reputation and ultimately loyalty were explored. The purpose of this paper is to investigate the relationships between factors that may lead to customer loyalty in online educational organizations.

Design/methodology/approach

Case study/quantitative methods were used.

Findings

This research assessed customer loyalty intentions by examining the service quality, commitment, satisfaction, and reputation of online students in master's level online programs.

Originality value

The relationship between service quality, commitment, satisfaction, reputation, and loyalty have not been adequately investigated in online master's programs.

Details

International Journal of Educational Management, vol. 28 no. 1
Type: Research Article
ISSN: 0951-354X

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Book part
Publication date: 14 December 2023

Witness Roya and Sandiso Ngcobo

Several studies have been conducted on social inequalities. Despite highlighting inequalities between the rich and poor, researchers often overlook the fact that disabled people…

Abstract

Several studies have been conducted on social inequalities. Despite highlighting inequalities between the rich and poor, researchers often overlook the fact that disabled people in Africa are marginalised more than their counterparts elsewhere. Using critical discourse analysis (CDA) as a theory and data analysis method, this study sought to answer two questions: (1) What is reported about the inclusion of disabled people in using digital media? (2) How is it reported? Twenty-two articles were purposively sampled: 15 from Newsday and 7 from The Herald published between 20 November 2017 and 24 September 2022. Findings indicate that the two papers exposed marginalisation of disabled people in an educative and informative way and had erudite analysis from disabled columnists. This was successful because the papers relied on the disabled community as sources of information and contributors of published material. The papers also engaged stakeholders such as corporates, government and civil society organisations. It is recommended that other newspapers and many forms of mass communication provide a representation of people with different forms of disabilities. Future studies could seek the views of disabled communities about their presentation in the digital media through disabled writers and providers of information.

Details

Digitisation, AI and Algorithms in African Journalism and Media Contexts
Type: Book
ISBN: 978-1-80455-135-6

Keywords

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Article
Publication date: 12 June 2017

Ali Saleh Alshomrani, Sapna Pandit, Abdullah K. Alzahrani, Metib Said Alghamdi and Ram Jiwari

The main purpose of this work is the development of a numerical algorithm based on modified cubic trigonometric B-spline functions for computational modelling of hyperbolic-type…

215

Abstract

Purpose

The main purpose of this work is the development of a numerical algorithm based on modified cubic trigonometric B-spline functions for computational modelling of hyperbolic-type wave equations. These types of equations describe a variety of physical models in the vibrations of structures, nonlinear optics, quantum field theory and solid-state physics, etc.

Design/methodology/approach

Dirichlet boundary conditions cannot be handled easily by cubic trigonometric B-spline functions. Then, a modification is made in cubic trigonometric B-spline functions to handle the Dirichlet boundary conditions and a numerical algorithm is developed. The proposed algorithm reduced the hyperbolic-type wave equations into a system of first-order ordinary differential equations (ODEs) in time variable. Then, stability-preserving SSP-RK54 scheme and the Thomas algorithm are used to solve the obtained system. The stability of the algorithm is also discussed.

Findings

A different technique based on modified cubic trigonometric B-spline functions is proposed which is quite different from the schemes developed (Abbas et al., 2014; Nazir et al., 2016) and depicts the computational modelling of hyperbolic-type wave equations.

Originality/value

To the best of the authors’ knowledge, this technique is novel for solving hyperbolic-type wave equations and the developed algorithm is free from quasi-linearization process and finite difference operators for time derivatives. This algorithm gives better results than the results discussed in literature (Dehghan and Shokri, 2008; Batiha et al., 2007; Mittal and Bhatia, 2013; Jiwari, 2015).

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Article
Publication date: 11 February 2021

Mohammad Ali Zakeri, Mahlagha Dehghan, Fatemeh Ghaedi Heidari, Hassan Pakdaman, Mehdi Mehdizadeh, Hamid Ganjeh, Mojtaba Sanji Rafsanjani and Sayed Mortaza Hossini Rafsanjanipoor

The increasing prevalence of coronavirus disease (COVID-19) is a global crisis that leads to physical and psychological outcomes for health-care workers, so this study aims to…

194

Abstract

Purpose

The increasing prevalence of coronavirus disease (COVID-19) is a global crisis that leads to physical and psychological outcomes for health-care workers, so this study aims to investigate the mental health outcomes (including general health, generalized anxiety disorder and posttraumatic stress disorder) in health-care workers in Rafsanjan, Iran.

Design/methodology/approach

By using convenience sampling, this cross-sectional study was conducted on 332 health-care workers working in public hospitals in southern Iran. Data collection lasted from March to April 2020. General Health Questionnaire (GHQ-28), Generalized Anxiety Disorder 7-item (GAD-7) and Impact of Event Scale were used to collect data. The data were then analyzed by using SPSS 25 and descriptive and inferential statistics (chi-square and multivariate logistic regression).

Findings

In total 45.5% of the participants had psychological disorder according to GHQ. In addition, 25.3% of the participants had GAD and 31.6% had posttraumatic stress disorder (PTSD). The results using multivariate logistic regression showed that only income was significantly associated with psychological disorders (95% confidence interval for odds ratio: 1.32–6.45, P = 0.008).

Practical implications

According to the results, the incidence of GAD and PTSD was high among health-care workers. Therefore, it is recommended that the psychological skills of health-care workers be strengthened through counseling and training programs.

Originality/value

This paper provides a novel analysis of mental health in health-care workers in Iran.

Details

Mental Health Review Journal, vol. 26 no. 2
Type: Research Article
ISSN: 1361-9322

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Article
Publication date: 20 April 2022

Hafiz Faiz Rasool, Muhammad Ali Qureshi, Abdul Aziz, Zain Ul Abiden Akhtar and Usman Ali Khan

This paper aims to improve the computational efficiency of higher-order accurate Noye–Hayman [NH (9,9)] implicit finite difference scheme for the solution of electromagnetic…

63

Abstract

Purpose

This paper aims to improve the computational efficiency of higher-order accurate Noye–Hayman [NH (9,9)] implicit finite difference scheme for the solution of electromagnetic scattering problems in tunnel environments.

Design/methodology/approach

The proposed method consists of two major steps: First, the higher-order NH (9,9) scheme is numerically discretized using the finite-difference method. The second step is to use an algorithm based on hierarchical interpolative factorization (HIF) to accelerate the solution of this scheme.

Findings

It is observed that the simulation results obtained from the numerical tests illustrate very high accuracy of the NH (9,9) method in typical tunnel environments. HIF algorithm makes the NH (9,9) method computationally efficient for two-dimensional (2D) or three-dimensional (3D) problems. The proposed method could help in reducing the computational cost of the NH (9,9) method very close to O(n) usual O(n3) for a full matrix.

Research limitations/implications

For simplicity, in this study, perfect electric conductor boundary conditions are considered. Future research may also include the utilization of meteorological techniques, including the effects of backward traveling waves, and make comparisons with the experimental data.

Originality/value

This study is directly applicable to typical problems in the field of tunnel propagation modeling for both national commercial and military applications.

Details

COMPEL - The international journal for computation and mathematics in electrical and electronic engineering , vol. 41 no. 5
Type: Research Article
ISSN: 0332-1649

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Article
Publication date: 16 July 2019

Qingang Xiong, Arash Khosravi, Narjes Nabipour, Mohammad Hossein Doranehgard, Aida Sabaghmoghadam and David Ross

This paper aims to numerically investigate the nanofluid flow, heat transfer and entropy generation during natural convection in an annulus.

231

Abstract

Purpose

This paper aims to numerically investigate the nanofluid flow, heat transfer and entropy generation during natural convection in an annulus.

Design/methodology/approach

The lattice Boltzmann method is used to simulate the velocity and temperature fields. Furthermore, some special modifications are applied to make the lattice Boltzmann method capable for simulation in the curved boundary conditions. The annulus is filled with CuO-water nanofluid. The dynamic viscosity of nanofluid is estimated using KLL (Koo-Kleinstreuer-Li) model, and the nanoparticle shape effect is taken account in calculating the thermal conductivity. On the other hand, the local/volumetric entropy generation is used to show the irreversibility under influence of different parameters.

Findings

The effect of considered governing parameters including Rayleigh number (103<Ra < 106); nanoparticle concentration (0<<0.04) and configuration of annulus on the flow structure; temperature field; and local and total entropy generation and heat transfer rate are presented.

Originality/value

The originality of this work is using of lattice Boltzmann method is simulation of natural convection in a curved configuration and using of Koo–Kleinstreuer–Li correlation for simulation of nanofluid.

Details

International Journal of Numerical Methods for Heat & Fluid Flow, vol. 29 no. 12
Type: Research Article
ISSN: 0961-5539

Keywords

Available. Content available
2361

Abstract

Details

Kybernetes, vol. 41 no. 7/8
Type: Research Article
ISSN: 0368-492X

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