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Article

Jia-Bao Liu, Morteza Bayati, Mazhar Abbas, Alireza Rahimi and Mohammad Naderi

The lattice Boltzmann method is used to simulate the nanofluid flow and heat transfer inside a finned multi-pipe heat exchanger.

Abstract

Purpose

The lattice Boltzmann method is used to simulate the nanofluid flow and heat transfer inside a finned multi-pipe heat exchanger.

Design/methodology/approach

The heat exchanger is filled with CuO-water nanofluid. The Koo–Kleinstreuer–Li (KKL) model is used to estimate the dynamic viscosity and considering the Brownian motion in the simulation. On the other hand, the influence of nanoparticles’ shapes on the heat transfer rate is considered, and the best efficient shape is selected to be used in the investigation.

Findings

The Rayleigh number, nanoparticle concentration and the thermal arrangements of internal active fins and bodies are the governing parameters. In addition, the impacts of these two parameters on the nanofluid flow, heat transfer rate, local and total entropy generation and heatline visualization are analyzed, comprehensively.

Originality/value

The originality of this work is using of lattice Boltzmann method for simulation of nanofluid flow and heat transfer during natural convection in a heat exchanger. Furthermore, influence of the shape of nanoparticles on the thermo-physical properties of nanofluid is analyzed using Koo–Kleinstreuer–Li correlation.

Details

International Journal of Numerical Methods for Heat & Fluid Flow, vol. 29 no. 8
Type: Research Article
ISSN: 0961-5539

Keywords

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Article

Abolfazl Darvish, Reza Naderi and Mohammad Reza Mohammadzadeh Attar

This research aims to provide a comparative study of the effect of conventional zinc phosphate (ZP) and zinc aluminium phosphate (ZPA) representing second generation of…

Abstract

Purpose

This research aims to provide a comparative study of the effect of conventional zinc phosphate (ZP) and zinc aluminium phosphate (ZPA) representing second generation of phosphate-based anticorrosion pigments on the protective performance and physical mechanical properties of a solvent-borne polyurethane (PU) coating.

Design/methodology/approach

The two pigments were incorporated into the coating at optimum pigment volume concentration. To evaluate the protective performance, electrochemical impedance spectroscopy (EIS) was used. The effect of modification of ZP on the physical–mechanical properties of the coatings was studied through dynamic mechanical thermal analysis. Moreover, Micro Vickers hardness and pull-off tests were used to evaluate the hydrolytic coating degradation.

Findings

EIS revealed the superior protective function of coatings incorporated with ZPA compared to those formulated with ZP. This behaviour might be attributed to the release of sufficient inhibiting species because of partial dissolving of the anticorrosive pigments when an electrolyte penetrates into the coating. In addition, the effectiveness of modification of ZP on the physical–mechanical properties of coatings was shown.

Research limitations/implications

As a classical replacement for the toxic chromates, ZP has been widely used in the formulation of protective coatings. However, undesirable inhibitive function of the pigment arising from its low solubility has made modification necessary. Because of the modified solubility, second generation of phosphate-based anticorrosion pigments has been reported to reveal superior performance.

Originality/value

According to the literature, no report can be found studying the effect of the second generation of phosphate-based anticorrosion pigments on the physical–mechanical properties of PU coatings. The main goal of this work is to study the correlation between physical–mechanical properties and anticorrosion performance of the PU coatings.

Details

Pigment & Resin Technology, vol. 45 no. 6
Type: Research Article
ISSN: 0369-9420

Keywords

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Article

Ahmad Naderi, Leila Nasrolahi Vosta, Abolghasem Ebrahimi and Mohammad Reza Jalilvand

The exploration of performance determinants in social enterprises has gained increasing relevance among researchers and practitioners, particularly in rural tourism. The…

Abstract

Purpose

The exploration of performance determinants in social enterprises has gained increasing relevance among researchers and practitioners, particularly in rural tourism. The purpose of this paper is to analyze the contributions of transformational leadership and social entrepreneurship to the performance of social enterprises in the context of rural tourism. Further, the mediating roles of social capital, creativity and social value were investigated.

Design/methodology/approach

Data were gathered through a survey of 168 employees of social enterprises operating in the rural tourism setting. Eight surveyors were sent out to conduct the survey. Data were analyzed by structural equation modeling (SEM) using AMOS 18.0.

Findings

The results of the SEM suggested that transformational leadership is positively associated with social value, social capital and performance of social enterprise. In addition, social entrepreneurship had a significant influence on social value, social capital and performance of social enterprise. Creativity and social value predicts the performance of social enterprise. Further, social capital was found to have a positive relationship with creativity. Finally, the mediating roles of social capital, creativity and social value were also confirmed. The findings thus highlight the power of the social value creation and social capital in the social enterprises operating in the rural destinations.

Social implications

The findings assert that social entrepreneurship and transformational leadership are key sources of social value creation, social capital and creativity in rural tourism context indicating the need for additional efforts on this kind of entrepreneurial activity. The findings can motivate policymakers to promote social entrepreneurship in rural tourism destinations as a means of stimulating bottom-up social capital and social value creation.

Originality/value

This study is among the first to examine the hypothesized relationships focusing on tourism social enterprises.

Details

International Journal of Sociology and Social Policy, vol. 39 no. 9/10
Type: Research Article
ISSN: 0144-333X

Keywords

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Article

Esmaeel Naderi, Mohammad Hadi Moayed and Mohsen Rahman

In this investigation, attempts were made to distinguish critical coating faults in order of repair priority in DCVG+CIPS survey data by new proposed equation for…

Abstract

Purpose

In this investigation, attempts were made to distinguish critical coating faults in order of repair priority in DCVG+CIPS survey data by new proposed equation for calculating IR drop. The paper aims to discuss these issues.

Design/methodology/approach

DCVG+CIPS, XRD, EDS.

Findings

A new empirical equation was developed which is able to predict the importance more precisely. Besides, the studies proved the corrosion products were mainly hematite and goethite, and the presence of Cl anions was not noticed. As a result, the corrosion attack had a form of non-uniform localized corrosion.

Originality/value

The values were gathered by DCVG+CIPS method of survey.

Details

Anti-Corrosion Methods and Materials, vol. 60 no. 6
Type: Research Article
ISSN: 0003-5599

Keywords

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Article

Masoud Darbandi, Mohammad Taeibi‐Rahni and Ali Reza Naderi

One major challenge in turbulent flow applications is to control the recirculation zone behind the backward‐facing step (BFS). One simple idea to do so is to modify the…

Abstract

Purpose

One major challenge in turbulent flow applications is to control the recirculation zone behind the backward‐facing step (BFS). One simple idea to do so is to modify the original BFS geometry, of course, without causing adverse or undesirable impacts on the original characteristics of the primary stream. The main objective of this work is to examine the solidity of the recirculation zone behind several different geometries which are slightly to moderately different from the original BFS geometry.

Design/methodology/approach

The implemented modifications cause complicated irregularities at the boundaries of the domain. The experience shows that the mesh distribution around these irregularities plays a critical role in the accuracy of the numerical solutions. To achieve the most accurate solutions with the least computational efforts, we use a robust hybrid strategy to distribute the computational grids in the domain. Additionally, a suitable numerical algorithm capable of handling hybrid grid topologies is properly extended to analyze the flow field. The current fully implicit method utilizes a physical pressure‐based upwinding scheme capable of working on hybrid mesh.

Findings

The extended algorithm is very robust and obtains very accurate solutions for the complex flow fields despite utilizing very coarse grid resolutions. Additionally, different proposed geometries revealed very similar separated regions behind the step and performed minor differences in the location of the reattachment points.

Research limitations/implications

The current study is fulfilled two‐dimensionally. However, the measurements in testing regular BFS problems have shown that the separated shear layer behind the step is not affected by 3D influences provided that the width of channel is sufficiently wide. A similar conclusion is anticipated here.

Practical implications

The problem occurs in the pipe and channel expansions, combustion chambers, flow over flying objects with abrupt contraction on their external surfaces, etc.

Originality/value

A novel pressure‐based upwinding strategy is properly employed to solve flow on multiblocked hybrid grid topologies. This strategy takes into account the physics associated with all the transports in the flow field. To study the impact of shape improvement, several modified BFS configurations were suggested and examined. These configurations need only little additional manufacturing cost to be fabricated.

Details

International Journal of Numerical Methods for Heat & Fluid Flow, vol. 16 no. 7
Type: Research Article
ISSN: 0961-5539

Keywords

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Article

Mehdi Rahnama, Abolfazl Vahedi, Arta Mohammad-Alikhani and Noureddine Takorabet

On-time fault diagnosis in electrical machines is a critical issue, as it can prevent the development of fault and also reduce the repairing time and cost. In brushless…

Abstract

Purpose

On-time fault diagnosis in electrical machines is a critical issue, as it can prevent the development of fault and also reduce the repairing time and cost. In brushless synchronous generators, the significance of the fault diagnosis is even more because they are widely used to generate electrical power all around the world. Therefore, this study aims to propose a fault detection approach for the brushless synchronous generator. In this approach, a novel extension of Relief feature selection method is developed.

Design/methodology/approach

In this paper, by taking the advantages of the finite element method (FEM), a brushless synchronous machine is modeled to evaluate the machine performance under two conditions. These conditions include the normal condition of the machine and one diode open-circuit of the rotating rectifier. Therefore, the harmonic behavior of the terminal voltage of the machine is obtained under these situations. Then, the harmonic components are ranked by using the extension of Relief to extract the most appropriate components for fault detection. Therefore, a fault detection approach is proposed based on the ranked harmonic components and support vector machine classifier.

Findings

The proposed diagnosis approach is verified by using an experimental test. Results show that by this approach open-circuit fault on the diode rectifier can effectively be detected by the accuracy of 98.5% and by using five harmonic components of the terminal voltage [1].

Originality/value

In this paper, a novel feature selection method is proposed to select the most effective FFT components based on an extension of Relief method, and besides, FEM modeling of a brushless synchronous generator for normal and one diode open-circuit fault.

Details

COMPEL - The international journal for computation and mathematics in electrical and electronic engineering , vol. 39 no. 5
Type: Research Article
ISSN: 0332-1649

Keywords

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Article

Abu Shamim Mohammad Arif and Jia Tina Du

Collaborative information searching is common for people when planning their group trip. However, little research has explored how tourists collaborate during information…

Abstract

Purpose

Collaborative information searching is common for people when planning their group trip. However, little research has explored how tourists collaborate during information search. Existing tourism Web portals or search engines rarely support tourists’ collaborative information search activities. Taking advantage of previous studies of collaborative tourism information search behavior, in the current paper the purpose of this paper is to propose the design of a collaborative search system collaborative tourism information search (ColTIS) to support online information search and travel planning.

Design/methodology/approach

ColTIS was evaluated and compared with Google Talk-embedded Tripadvisor.com through a user study involving 18 pairs of participants. The data included pre- and post-search questionnaires, web search logs and chat history. For quantitative measurement, statistical analysis was performed using SPSS; for log data and the qualitative feedback from participants, the content analysis was employed.

Findings

Results suggest that collaborative query formulation, division of search tasks, chatting and results sharing are important means to facilitate tourists’ collaborative search. ColTIS was found to outperform Tripadvisor significantly regarding the ease of use, collaborative support and system usefulness.

Originality/value

The innovation of the study lies in the development of an integrated real-time collaborative tourism information search system with unique features. These features include collaborative query reformulation, travel planner and automatic result and query sharing that assist multiple people search for holiday information together. For system designers and tourism practitioners, implications are provided.

Details

Online Information Review, vol. 43 no. 3
Type: Research Article
ISSN: 1468-4527

Keywords

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Article

Nur Zulaikha Bt Mohamed Sadom, Farzana Quoquab and Jihad Mohammad

The prevailing overconsumption issue in the hotel industry is attributable mainly to the irresponsible consumption behaviour of hotel guests. In parallel with Islamic…

Abstract

Purpose

The prevailing overconsumption issue in the hotel industry is attributable mainly to the irresponsible consumption behaviour of hotel guests. In parallel with Islamic principles, which advocate abstinence from excess consumption and frugality, the “waste not, want not” notion can be considered as one of the effective solutions to this problem. However, little is known about the factors that drive frugality amongst Muslim tourists. In addressing this gap, this study aims to predict the effect of environmental advertising and green attitude on frugality in the context of the Malaysian hotel industry. The study also tests the mediating role of the green attitude between environmental advertising and frugality. Furthermore, it examines the role of price consciousness as a moderator of the green attitude-frugality link.

Design/methodology/approach

The stimulus-organism-response theory was used to develop the conceptual framework of this study. A cross-sectional method was used to collect 222 usable questionnaires from Muslim tourists in Malaysia. The hypothesised relationships were tested using the structural equation modelling, partial least squares approach.

Findings

The study found support for the direct effect of environmental advertising and green attitude on frugality. It also confirmed the mediating effect of the green attitude in the environmental advertising-frugality link. However, price consciousness did not moderate the relationship.

Practical implications

The findings of the study provide valuable insight for hoteliers in developing a green strategy that will foster frugality amongst Muslim hotel guests. It will also help them develop better strategies for the frugal segment, especially for the Muslim community.

Originality/value

The study is amongst the pioneers in investigating frugality in the tourism industry. It is also the first to introduce price consciousness as a moderator of the relationship between the green attitude and frugality. Furthermore, its examination of frugality amongst Muslim hotel guests is a new contribution to the literature.

Details

Journal of Islamic Marketing, vol. ahead-of-print no. ahead-of-print
Type: Research Article
ISSN: 1759-0833

Keywords

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Abstract

Purpose

The purpose of this paper is to assess the quality of Iranian university libraries.

Design/methodology/approach

This first systematic review and meta-analysis were based on the PRISMA guidelines by searching in national and international databases from 2003 to January 2017 with standard Persian and English keywords. Data searching, extracting and quality appraising were completed by two researchers, independently. Any unexpected documents were assessed by a third expert researcher. Data were extracted in accordance with the “Strength of the Reporting of Observational Studies in Epidemiology” checklist after the final selection of appraised documents. Random effects size based on Cochrane test and I2 were used for combining the obtained results from different studies together by considering the heterogeneity of studies.

Findings

Based on the meta-analysis conducted in 25 (6.42 percent) included studies, the total sample size was estimated. According to three dimensions of LibQUAL, findings of current information control, affect of service and the library as a place were estimated as 5.37 [CI95%: 5.02, 5.73], 6.91 [CI95%: 5.56, 6.26], and 5.46 percent [CI95%: 5.2, 5.73], respectively. Also, mean of service adequacy and superiority gap are equal to 0.07 [CI95%: −0.22, 0.36] and −2.06 [CI95%: −2.89, −1.23], respectively. There was a significant correlation between three dimensions of service quality and service superiority gap of LibQUAL and geographical regions of Iran (p<0.01). Also, a significant correlation was found between the gaps of services and three aspects of LibQUAL model and published years through a meta-regression test (p<0.01).

Practical implications

The results obtained from the present study showed that users are relatively satisfied with the quality of services provided by Iranian university libraries. An improvement in the quality of library services can promote the scientific level of universities.

Originality/value

The results of the present systematic review and meta-analysis study demonstrate a vital connection between primary research studies and decision-making for policymakers in Iranian university libraries to increase quality services.

Details

Performance Measurement and Metrics, vol. 19 no. 3
Type: Research Article
ISSN: 1467-8047

Keywords

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Article

Mohammad Hosein Nadreri, Mohamad Bameni Moghadam and Asghar Seif

The purpose of this paper is to develop an economic statistical design based on the concepts of adjusted average time to signal (AATS) and ANF for X…

Abstract

Purpose

The purpose of this paper is to develop an economic statistical design based on the concepts of adjusted average time to signal (AATS) and ANF for X ¯ control chart under a Weibull shock model with multiple assignable causes.

Design/methodology/approach

The design used in this study is based on a multiple assignable causes cost model. The new proposed cost model is compared with the same cost and time parameters and optimal design parameters under uniform and non-uniform sampling schemes.

Findings

Numerical results indicate that the cost model with non-uniform sampling cost has a lower cost than that with uniform sampling. By using sensitivity analysis, the effect of changing fixed and variable parameters of time, cost and Weibull distribution parameters on the optimum values of design parameters and loss cost is examined and discussed.

Practical implications

This research adds to the body of knowledge relating to the quality control of process monitoring systems. This paper may be of particular interest to practitioners of quality systems in factories where multiple assignable causes affect the production process.

Originality/value

The cost functions for uniform and non-uniform sampling schemes are presented based on multiple assignable causes with AATS and ANF concepts for the first time.

Details

International Journal of Quality & Reliability Management, vol. 36 no. 4
Type: Research Article
ISSN: 0265-671X

Keywords

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