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Article
Publication date: 4 January 2013

Mazeyar Parvinzadeh Gashti, Mohammad Yousefpour Navid and Mohammad Hossein Rahimi

Silicone softeners are widely used in the textile industry to improve the performance of textile products. The thermal characteristics and flammability of polyester…

Abstract

Purpose

Silicone softeners are widely used in the textile industry to improve the performance of textile products. The thermal characteristics and flammability of polyester fabrics can be influenced by these compounds, which need to be considered, as important issues of human safety. The purpose of this paper is to investigate the changes induced on the polyester fibre by silicone softener treatment using a pad/dry/cure method.

Design/methodology/approach

The fibres were first treated with nano‐ and microemulsion silicone softeners. The influence of the silicone emulsion type on thermal properties and flammability of the resultant samples were investigated by various analytical techniques, namely, the differential scanning calorimetry (DSC), thermal gravimetric analysis (TGA), dynamical mechanical thermal analysis (DMTA) and horizontal flammability test (HFT).

Findings

Results showed that the silicone softeners increase the thermal degradation and flammability of the polyethylene terephthalate (PET) substrate.

Originality/value

The paper's study of thermal and flammability of the silicone‐treated sample is novel and can be used to optimize the properties of silicone polymers during production and consumption.

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Article
Publication date: 23 November 2018

Mahmoud Salari, Emad Hasani Malekshah, Mohammad Reza Sarlak, Masoud Hasani Malekshah and Mohammad Pilfoush

The purpose of this paper is to investigate the three-dimensional natural convection and entropy generation in a cuboid enclosure filled with two immiscible fluids of…

Abstract

Purpose

The purpose of this paper is to investigate the three-dimensional natural convection and entropy generation in a cuboid enclosure filled with two immiscible fluids of nanofluid and air.

Design/methodology/approach

One surface of the enclosure is jagged and another one is smooth. The finite volume approach is applied for computation. There are two partially side heaters. Furthermore, the Navier–Stokes equations and entropy generation formulation are solved in the 3D form.

Findings

The effects of different governing parameters, such as the jagged surface (JR=0, 0.02, 0.04, 0.08, 0.12 and 0.16), Rayleigh number (103Ra⩽106) and solid volume fraction of nanofluid (φ=1, 1.5, 2 vol%), on the fluid flow, temperature field, Nusselt number, volumetric entropy generation and Bejan number are presented, comprehensively. The results indicate that the average Nusselt number increases with the increase in the Rayleigh number and solid volume fraction of nanofluid. Moreover, the flow structure is significantly affected by the jagged surface.

Originality/value

The originality of this work is to analyze the natural-convection fluid flow and heat transfer under the influence of jagged surfaces of electrodes in high-current lead–acid batteries.

Details

Multidiscipline Modeling in Materials and Structures, vol. 15 no. 1
Type: Research Article
ISSN: 1573-6105

Keywords

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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.

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

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Article
Publication date: 17 June 2021

Morteza Rahimi, Nima Jafari Navimipour, Mehdi Hosseinzadeh, Mohammad Hossein Moattar and Aso Darwesh

This paper follows a systematic literature review (SLR) method covering the published studies until March 2021. The authors have extracted the related studies from…

Abstract

Purpose

This paper follows a systematic literature review (SLR) method covering the published studies until March 2021. The authors have extracted the related studies from different online databases utilizing quality-assessment-criteria. In order to review high-quality studies, 32 papers have been chosen through the paper selection process. The selected papers have been categorized into three main groups, decision-making methods (17 papers), meta-heuristic methods (8 papers) and fuzzy-based methods (7 papers). The existing methods in each group have been examined based on important qualitative parameters, namely, time, cost, scalability, efficiency, availability and reliability.

Design/methodology/approach

Cloud computing is known as one of the superior technologies to perform large-scale and complex computing. With the growing tendency of network service users to utilize cloud computing, web service providers are encouraged to provide services with various functional and non-functional features and supply them in a service pool. In this regard, choosing the most appropriate services to fulfill users' requirements becomes a challenging problem. Since the problem of service selection in a cloud environment is known as a nondeterministic polynomial time (NP)-hard problem, many efforts have been made in recent years. Therefore, this paper aims to study and assess the existing service selection approaches in cloud computing.

Findings

The obtained results indicate that in decision-making methods, the assignment of proper weights to the criteria has a high impact on service ranking accuracy. Also, since service selection in cloud computing is known as an NP-hard problem, utilizing meta-heuristic algorithms to solve this problem offers interesting advantages compared to other approaches in discovering better solutions with less computational effort and moving quickly toward very good solutions. On the other hand, since fuzzy-based service selection approaches offer search results visually and cover quality of service (QoS) requirements of users, this kind of method is able to facilitate enhanced user experience.

Research limitations/implications

Although the current paper aimed to provide a comprehensive study, there were some limitations. Since the authors have applied some filters to select the studies, some effective works may have been ignored. Generally, this paper has focused on journal papers and some effective works published in conferences. Moreover, the works published in non-English formats have been excluded. To discover relevant studies, the authors have chosen Google Scholar as a popular electronic database. Although Google Scholar can offer the most valid approaches, some suitable papers may not be observed during the process of article selection.

Practical implications

The outcome of the current paper will be useful and valuable for scholars, and it can be a roadmap to help future researchers enrich and improve their innovations. By assessing the recent efforts in service selection in cloud computing and offering an up-to-date comparison of the discussed works, this paper can be a solid foundation for understanding the different aspects of service selection.

Originality/value

Although service selection approaches have essential impacts on cloud computing, there is still a lack of a detailed and comprehensive study about reviewing and assessing existing mechanisms in this field. Therefore, the current paper adopts a systematic method to cover this gap. The obtained results in this paper can help the researchers interested in the field of service selection. Generally, the authors have aimed to specify existing challenges, characterize the efficient efforts and suggest some directions for upcoming studies.

Details

Kybernetes, vol. ahead-of-print no. ahead-of-print
Type: Research Article
ISSN: 0368-492X

Keywords

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Article
Publication date: 2 November 2018

Alireza Rahimi, Abbas Kasaeipoor, Emad Hasani Malekshah, Mohammad Mehdi Rashidi and Abimanyu Purusothaman

This study aims to investigate the three-dimensional natural convection and entropy generation in a cuboid enclosure filled with CuO-water nanofluid.

Abstract

Purpose

This study aims to investigate the three-dimensional natural convection and entropy generation in a cuboid enclosure filled with CuO-water nanofluid.

Design/methodology/approach

The lattice Boltzmann method is used to solve the problem numerically. Two different multiple relaxation time (MRT) models are used to solve the problem. The D3Q7–MRT model is used to solve the temperature field, and the D3Q19 is used to solve the fluid flow of natural convection within the enclosure.

Findings

The influences of different Rayleigh numbers (103 < Ra < 106) and solid volume fractions (0 < f < 0.04) on the fluid flow, heat transfer, total entropy generation, local heat transfer irreversibility and local fluid friction irreversibility are presented comprehensively. To predict thermo–physical properties, dynamic viscosity and thermal conductivity, of CuO–water nanofluid, the Koo–Kleinstreuer–Li (KKL) model is applied to consider the effect of Brownian motion on nanofluid properties.

Originality/value

The originality of this work is to analyze the three-dimensional natural convection and entropy generation using a new numerical approach of dual-MRT-based lattice Boltzmann method.

Details

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

Keywords

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Article
Publication date: 13 June 2019

Mohammad Reza Salimpour, Mohammad Hossein Karimi Darvanjooghi, Ali Abdollahi, Arash Karimipour and Marjan Goodarzi

A boiling surface with different initial roughness and under various nanoparticles volume fractions was studied in present work.

Abstract

Purpose

A boiling surface with different initial roughness and under various nanoparticles volume fractions was studied in present work.

Design/methodology/approach

Develop a correlation and sensitivity analysis.

Findings

The results showed that for small (7.3 nm) and much larger (about 2,000 nm) surface roughness, compared to nanoparticle size of around 25 nm, the heat transfer rate of nanofluid diminishes relative to that of base fluid. The results also demonstrated that the boiling heat transfer rate is reduced by increasing the concentration of nanoparticles. For larger boiling surface roughness (480 nm) and nanoparticles volume fractions of less than 0.1 Vol.%, the value of heat transfer increases with the increase of nanoparticles concentration; and for those of more than 0.1 Vol.%, heat transfer rate decreases by adding more nanoparticles, significantly.

Originality/value

Finally, an equation was presented for estimating the wall superheat and the Csf coefficient in terms of mentioned parameters.

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: 1 June 2021

Hossein Bakhshi, Hiwa Weisi and Nouroddin Yousofi

This paper explores the challenges of conducting qualitative research from ELT (English Language Teaching) Ph.D. candidates' perspectives.

Abstract

Purpose

This paper explores the challenges of conducting qualitative research from ELT (English Language Teaching) Ph.D. candidates' perspectives.

Design/methodology/approach

The participants of the study consisted of 30 Iranian Ph.D. students majoring in ELT. The semi-structured interview was employed to investigate the heart of experiences, issues and concerns of participants with regard to conducting qualitative research (QLR) challenges. To analyze the collected data, the recorded interviews were transcribed, and then the grounded theory approach was employed (Charmaz, 2006).

Findings

The results revealed that the major challenges of the participants consist of the credibility of QLR in ELT contexts, hermeneutic and fuzzy nature of QLR, qualitative data analysis and interpretation, publishing qualitative findings and the system of measuring professors' productivity.

Originality/value

The findings may help professors, mainly EFL ones, in research mentoring and developing research syllabi for graduate students. In addition, it may motivate Ph.D. candidates to employ QLR methods in their research studies. The pedagogical and theoretical implications of the study are discussed at the end of the paper.

Details

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

Keywords

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Article
Publication date: 20 January 2020

Habeeb Abdulrauf Salihu and Amin Jafari

The purpose of this paper is to examine the various anti-corruption strategies used to fight economic and financial crimes in both the public and private sectors in Iran.

Abstract

Purpose

The purpose of this paper is to examine the various anti-corruption strategies used to fight economic and financial crimes in both the public and private sectors in Iran.

Design/methodology/approach

This paper relied essentially on a secondary source of information. Materials used were collected in an eclectic manner from published outlets such as journal publications, books, online sources and newspaper reports. Also, official documents and statutes were also used. This study’s scope is limited to issues and analysis relating to measures adopted to combat corruption in Iran.

Findings

The legal and institutional frameworks analysed indicated that Iran has a robust anti-corruption scheme. However, there is no adequate measure available to gauge the effectiveness of these measures.

Practical implications

The paper concludes that conventional anti-corruption methods are not enough to fight corruption in this present time, thus, the implementation of whistle-blower policy and allowing freedom of operation of the civil society organisations and media would assist in the fight against corruption in Iran.

Originality/value

The paper provides the legal and institutional anti-corruption frameworks in Iran. It explores the three major approaches or methods of combating corruption and other corrupt practices in Iran.

Details

Journal of Money Laundering Control, vol. 23 no. 1
Type: Research Article
ISSN: 1368-5201

Keywords

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Article
Publication date: 7 June 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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