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Article
Publication date: 1 January 2006

Mohammad B. Ayani, Javad A. Esfahani and Antonio C.M. Sousa

To show the effect of radiation from the heat source and the variation of fluid properties on the laminar natural convection induced by a line heat source.

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Abstract

Purpose

To show the effect of radiation from the heat source and the variation of fluid properties on the laminar natural convection induced by a line heat source.

Design/methodology/approach

The governing equations – Navier‐Stokes and energy equation are discretized in a staggered grid by a control volume approach, and they are solved using a segregated technique. The equations for the fluid and solid (line heat source) phases are solved simultaneously. The three sides of the computational domain are open boundary. Some of the physical and thermo‐physical properties of the fluid (air) such as density, thermal conductivity and viscosity were considered to vary with temperature.

Findings

The present predictions are compared with those using the Boussinesq approximation, with the results for the boundary layer equations, and with the experimental results. The present predictions reveal considerable departure from the Boussinesq‐based solution and from the boundary layer results. This study also shows the radiation exchange between the heat source and surrounding has major effect in the results. Thus, the departure between the experimental and analytical results can be explained by the effect of radiation exchange.

Research limitations/implications

In this work, just studied steady‐state laminar thermal plume with the effects of radiation from heat source and the variation of air properties with temperature while it is propose to extend this work to transient and/or turbulent flow.

Originality/value

The effect of radiation from a line heat source on the flow filed around the source and offers enhancement of design to thermal engineers.

Details

International Journal of Numerical Methods for Heat & Fluid Flow, vol. 16 no. 1
Type: Research Article
ISSN: 0961-5539

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Article
Publication date: 28 November 2023

Mohamad Javad Baghiat Esfahani and Saeed Ketabi

This study attempts to evaluate the effect of the corpus-based inductive teaching approach with multiple academic corpora (PICA, CAEC and Oxford Corpus of Academic English) and…

79

Abstract

Purpose

This study attempts to evaluate the effect of the corpus-based inductive teaching approach with multiple academic corpora (PICA, CAEC and Oxford Corpus of Academic English) and conventional deductive teaching approach (i.e., multiple-choice items, filling the gap, matching and underlining) on learning academic collocations by Iranian advanced EFL learners (students learning English as a foreign language).

Design/methodology/approach

This is a quasi-experimental, quantitative and qualitative study.

Findings

The result showed the experimental group outperformed significantly compared with the control group. The experimental group also shared their perception of the advantages and disadvantages of the corpus-assisted language teaching approach.

Originality/value

Despite growing progress in language pedagogy, methodologies and language curriculum design, there are still many teachers who experience poor performance in their students' vocabulary, whether in comprehension or production. In Iran, for example, even though mandatory English education begins at the age of 13, which is junior and senior high school, students still have serious problems in language production and comprehension when they reach university levels.

Details

Journal of Applied Research in Higher Education, vol. 16 no. 4
Type: Research Article
ISSN: 2050-7003

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Article
Publication date: 15 August 2016

Reza Salehzadeh, Javad Khazaei Pool and Samaneh Soleimani

The purpose of this paper is to examine how brand personality and brand equity affect intentions to revisit a city tourism destination.

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Abstract

Purpose

The purpose of this paper is to examine how brand personality and brand equity affect intentions to revisit a city tourism destination.

Design/methodology/approach

Statistical population of this research consisted of those visitors who traveled to Pool city in Iran during Spring 2015. A structural equation model test with maximum likelihood estimation was performed to test the relationship among the research variables using 367 participants.

Findings

The empirical results from the structural model suggest that brand personality and brand equity positively influenced revisit intention. Furthermore, brand personality was a direct antecedent of brand equity.

Originality/value

An integrated model of brand personality, brand equity and revisit intention was tested in a tourism city in the context of a developing economy. The combination of a developing country context and the significance of destination brand enhance the contextual contribution of the paper.

Details

Tourism Review, vol. 71 no. 3
Type: Research Article
ISSN: 1660-5373

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Article
Publication date: 22 August 2024

Iman Bashtani and Javad Abolfazli Esfahani

This study aims to introduce a novel machine learning feature vector (MLFV) method to bring machine learning to overcome the time-consuming computational fluid dynamics (CFD…

52

Abstract

Purpose

This study aims to introduce a novel machine learning feature vector (MLFV) method to bring machine learning to overcome the time-consuming computational fluid dynamics (CFD) simulations for rapidly predicting turbulent flow characteristics with acceptable accuracy.

Design/methodology/approach

In this method, CFD snapshots are encoded in a tensor as the input training data. Then, the MLFV learns the relationship between data with a rod filter, which is named feature vector, to learn features by defining functions on it. To demonstrate the accuracy of the MLFV, this method is used to predict the velocity, temperature and turbulent kinetic energy fields of turbulent flow passing over an innovative nature-inspired Dolphin turbulator based on only ten CFD data.

Findings

The results indicate that MLFV and CFD contours alongside scatter plots have a good agreement between predicted and solved data with R2 ≃ 1. Also, the error percentage contours and histograms reveal the high precisions of predictions with MAPE = 7.90E-02, 1.45E-02, 7.32E-02 and NRMSE = 1.30E-04, 1.61E-03, 4.54E-05 for prediction velocity, temperature, turbulent kinetic energy fields at Re = 20,000, respectively.

Practical implications

The method can have state-of-the-art applications in a wide range of CFD simulations with the ability to train based on small data, which is practical and logical regarding the number of required tests.

Originality/value

The paper introduces a novel, innovative and super-fast method named MLFV to address the time-consuming challenges associated with the traditional CFD approach to predict the physics of turbulent heat and fluid flow in real time with the superiority of training based on small data with acceptable accuracy.

Details

International Journal of Numerical Methods for Heat & Fluid Flow, vol. 34 no. 10
Type: Research Article
ISSN: 0961-5539

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Article
Publication date: 20 November 2017

Reza Salehzadeh, Javad Khazaei Pool, Reihaneh Alsadat Tabaeeian, Mojtaba Amani and Marjan Mortazavi

The purpose of this paper is to investigate the effects of internal marketing and market orientation on organizational performance based on the balanced scorecard (BSC).

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Abstract

Purpose

The purpose of this paper is to investigate the effects of internal marketing and market orientation on organizational performance based on the balanced scorecard (BSC).

Design/methodology/approach

A cross-sectional research design, drawing upon a questionnaire survey, was used to collect data from a sample of restaurants. Structural equation modeling was performed to test the relationship among the research variables using findings from the 164 participants.

Findings

The results revealed that internal marketing positively influenced market orientation and performance. In addition, market orientation was a direct antecedent of performance.

Originality/value

The findings provide important academic, practical and political implications for restaurant industry.

Details

Measuring Business Excellence, vol. 21 no. 4
Type: Research Article
ISSN: 1368-3047

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Article
Publication date: 4 December 2018

Navid Moghaddaszadeh, Saman Rashidi and Javad Abolfazli Esfahani

This paper aims to use the second law of thermodynamic to evaluate the potential of gear-ring turbulator in a three-dimensional heat exchanger tube. Accordingly, a numerical…

82

Abstract

Purpose

This paper aims to use the second law of thermodynamic to evaluate the potential of gear-ring turbulator in a three-dimensional heat exchanger tube. Accordingly, a numerical simulation is performed to obtain the irreversibilities in a three-dimensional heat exchanger tube equipped with some gear-ring turbulators for turbulence regime.

Design/methodology/approach

A numerical simulation is performed to obtain the irreversibilities in a three-dimensional heat exchanger tube equipped with some gear-ring turbulators for turbulence regime. The analysis is carried out based on shear stress transport (SST) k-ω turbulent model. The influences of different parameters containing tooth number, free-space length ratios and Reynolds number on frictional and thermal irreversibilities and Bejan number are discussed.

Findings

The results indicated that the thermal irreversibility reduces by decreasing the tooth number. For example, the thermal entropy generation decreases about 25.81 per cent by decreasing the tooth number in the range of 24 to 0 at Re = 6,000. Moreover, the frictional entropy generation decreases by increasing the tooth number as the gear with more tooth number causes a lower flow disturbance.

Originality/value

The present study arranged a numerical work to study the potential of a gear-ring turbulator in a heat exchanger tube from first and second laws of thermodynamic viewpoint. The turbulent flow is considered for this problem. The literature review showed that the usage of a gear-ring turbulator in a heat exchanger tube is not investigated from the second law of thermodynamic viewpoint by previous studies. As a result, the influences of different parameters containing tooth number, free-space length ratios and Reynolds number on frictional and thermal irreversibilities and Bejan number are discussed.

Details

International Journal of Numerical Methods for Heat & Fluid Flow, vol. 29 no. 4
Type: Research Article
ISSN: 0961-5539

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Article
Publication date: 6 June 2016

Saman Rashidi, Javad Abolfazli Esfahani, Mohammad Sadegh Valipour, Masoud Bovand and Ioan Pop

The analysis of the flow field and heat transfer around a tube row or tube banks wrapped with porous layer have many related engineering applications. Examples include the reactor…

182

Abstract

Purpose

The analysis of the flow field and heat transfer around a tube row or tube banks wrapped with porous layer have many related engineering applications. Examples include the reactor safety analysis, combustion, compact heat exchangers, solar power collectors, high-performance insulation for buildings and many another applications. The purpose of this paper is to perform a numerical study on flows passing through two circular cylinders in side-by-side arrangement wrapped with a porous layer under the influence of a magnetic field. The authors focus the attention to the effects of magnetic field, Darcy number and pitch ratio on the mechanism of convection heat transfer and flow structures.

Design/methodology/approach

The Darcy-Brinkman-Forchheimer model for simulating the flow in porous medium along with the Maxwell equations for providing the coupling between the flow field and the magnetic field have been used. Equations with the relevant boundary conditions are numerically solved using a finite volume approach. In this study, Stuart and Darcy numbers are varied within the range of 0 < N < 3 and 1e-6 < Da < 1e-2, respectively, and Reynolds and Prandtl numbers are equal to Re=100 and Pr=0.71, respectively.

Findings

The results show that the drag coefficient decreases for N < 0.6 and increases for N > 0.6. Also, the effect of magnetic field is negligible in the gap between two cylinders because the magnetic field for two cylinders counteracts each other in these regions.

Originality/value

To the authors knowledge, in the open literature, flow passing over two circular cylinders in side-by-side arrangement wrapped with a porous layer has been rarely investigated especially under the influence of a magnetic field.

Details

International Journal of Numerical Methods for Heat & Fluid Flow, vol. 26 no. 5
Type: Research Article
ISSN: 0961-5539

Keywords

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Article
Publication date: 5 March 2018

Reza Salehzadeh, Javad Khazaei Pool and Amir Hossein Jafari Najafabadi

The purpose of this research is to explore the relationship between corporate social responsibility (CSR), brand image (BI) and brand equity (BE) in the banking industry of the…

1993

Abstract

Purpose

The purpose of this research is to explore the relationship between corporate social responsibility (CSR), brand image (BI) and brand equity (BE) in the banking industry of the Islamic Republic of Iran.

Design/methodology/approach

Using the deductive approach as the methodology and 213 valid questionnaires returned by customers of Iranian banks in four big cities of Iran, this study tests the relationship between CSR, BI and BE in eight hypotheses. The data were analyzed by the partial least squares method.

Findings

The results of this research show that CSR has a significant direct effect on BI. Also, BI has a significant direct effect on BE.

Originality/value

This research provides valuable insight for studying the relationship between CSR, BI and BE. The results of this study provide a better understanding of the role of CSR in customers’ attitudes and behaviors in the banking industry.

Details

Journal of Islamic Accounting and Business Research, vol. 9 no. 2
Type: Research Article
ISSN: 1759-0817

Keywords

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Article
Publication date: 13 March 2017

Javad Khazaei Pool, Reza Salehzadeh and Rashid Khalilakbar

Limitations of producing energy and the increasing demands in the electricity market in Iran have not only drawn the attention of authorities in the energy industry toward…

486

Abstract

Purpose

Limitations of producing energy and the increasing demands in the electricity market in Iran have not only drawn the attention of authorities in the energy industry toward optimization of energy consumption, but also created marketing approaches toward these objectives. In this respect, it is important and even necessary to modify energy consumption behaviors. The purpose of this study is to examine the impact of the criteria of an effective Internet advertisement for modification of energy consumption.

Design/methodology/approach

To provide a detailed understanding of customers’ perceptions of energy consumption advertising, a survey study was conducted. The research model is first validated and the formulated hypotheses are tested using the structural equation model (SEM).

Findings

The results showed that the audience’s attention, interest and desire for a piece of advertisement can predict their consumption behavior.

Originality/value

This study is one of the pioneer studies that highlights the importance of advertising toward modification of energy consumption. It seems that, the identification of the causal relations among attention, interest, desire and action, has not yet been clearly validated in the previous literature. This research contributes to the literature by developing and testing a comprehensive research model using SEM. So, the current paper offers vital guidelines to social marketers who are planning to modify energy consumption.

Details

Journal of Science and Technology Policy Management, vol. 8 no. 1
Type: Research Article
ISSN: 2053-4620

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Article
Publication date: 7 September 2015

Masoud Bovand, Saman Rashidi, Masoomeh Dehesht and Javad Abolfazli Esfahani

The purpose of this paper is to implement the numerical analysis based on finite volume method to compare the effects of stress-jump (SJ) and stress-continuity (SC) conditions on…

274

Abstract

Purpose

The purpose of this paper is to implement the numerical analysis based on finite volume method to compare the effects of stress-jump (SJ) and stress-continuity (SC) conditions on flow structure around and through a porous circular cylinder.

Design/methodology/approach

In this study, a steady flow of a viscous, incompressible fluid around and through a porous circular cylinder of diameter “D,” using Darcy-Brinkman-Forchheimer’s equation in the porous region, is discussed. The SJ condition proposed by Ochoa-Tapia and Whitaker is applied at the porous-fluid interface and compared with the traditional interfacial condition based on the SC condition in fluid and porous media. Equations with the relevant boundary conditions are numerically solved using a finite volume approach. In this study, Reynolds and Darcy numbers are varied within the ranges of 1 < Re < 40 and 10-7 < Da < 10-2, respectively, and the porosities are e=0.45, 0.7 and 0.95.

Findings

Results show that the SJ condition leads to a much smaller boundary layer within porous medium near the interface as compared to the SC condition. Two interfacial conditions yield similar results with decrease in porosity.

Originality/value

There is no published research in the literature about the effects of important parameters, such as Porosity and Darcy numbers on different fluid-porous interface conditions for a porous cylinder and comparison the effects of SJ and SC conditions on flow structure around and through a porous circular cylinder.

Details

International Journal of Numerical Methods for Heat & Fluid Flow, vol. 25 no. 7
Type: Research Article
ISSN: 0961-5539

Keywords

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