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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.

407

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

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Article
Publication date: 7 August 2017

Deirdre M. D’Orazio

The purpose of this paper is to examine the degree to which a US prison-based sexual offender treatment program adheres to the best practice responsivity principle and to shed…

302

Abstract

Purpose

The purpose of this paper is to examine the degree to which a US prison-based sexual offender treatment program adheres to the best practice responsivity principle and to shed light on why prison-based programs tend to have worse recidivism outcomes than community programs. Results will facilitate program development efforts as they transition from programming developed prior to the risk-needs-responsivity knowledge about what works in treatment.

Design/methodology/approach

A mix of qualitative and quantitative methods assessed treatment methods, therapeutic climate, group therapy environment, therapist style, and staff and participants’ perceptions.

Findings

Overall, the analyses revealed insufficient adherence to the responsivity principle. The program used methods known to be effective with sexual offenders, but with deficient implementation. In group therapy sessions, therapeutic style deficiencies were demonstrated for stimulating growth, nurturance, and direction and control. Treatment program advancement was associated with group environment declines in cohesion, leader support, expressiveness, independence, and task orientation.

Originality/value

Results suggest that improved treatment response can be achieved by modifying methods and style to foster participant internal control, eliminate unnecessary external control and fear-based compliance, maximize participant autonomy; implement strengths-based approaches and fewer deficit-based interventions; monitor and minimize participant shame, and create a transparent and consistent program milieu, with clear communication, individualization, and adequate resources. Study limitations include a lack of recidivism outcomes; that it is a single prison sample, excludes female and juvenile offenders, and lacks a community-based control group. Nonetheless, despite inherent responsivity vulnerabilities compared to community-based programs, this study indicates several ways that program developers can enhance adherence to the responsivity principle in institutional-based programs.

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Article
Publication date: 6 November 2009

M. D'Orazio, C. Di Perna and F. Stazi

The purpose of this paper is to present the results of an experimental study aimed at analysing the effect of the roof tile air permeability on the thermal performances of…

485

Abstract

Purpose

The purpose of this paper is to present the results of an experimental study aimed at analysing the effect of the roof tile air permeability on the thermal performances of ventilation ducts in the roof. The main reason underlying this study is the fact that the theoretical reference assumed for the manufacture and sizing of ventilation ducts (the accepted theory on roof ventilation) is clearly limited when applied to ducts which are not perfectly airtight (Hens) and results in an oversizing of the ventilation ducts.

Design/methodology/approach

A section of roof is built, covered with different tiles and environmental and meteorological data collected. The data are analysed statistically.

Findings

The results show that the permeability of the layer of tiles determines heat losses which are in addition to those connected with the stack effect in a perfectly airtight duct with the same features. The results also confirm the correlation which has already been demonstrated between the geometric ratio of the length of the duct divided by its height and the amount of heat dissipated by the roof (Sandberg and Moshfeg).

Originality/value

This study analyses the performance of the roofs only during the summer season. The research is therefore continuing with a long‐term (one year) analysis of the roofs characterised by a high level of roof tile permeability so as to understand the consequences that the presence of a ventilation duct in systems with air permeable roofing may have on the thermal efficiency of the roof.

Details

Structural Survey, vol. 27 no. 5
Type: Research Article
ISSN: 0263-080X

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Book part
Publication date: 2 November 2009

Caroline Bayart, Patrick Bonnel and Catherine Morency

Data fusion and the combination of multiple data sources have been part of travel survey processes for some time. In the current context, where technologies and information…

Abstract

Data fusion and the combination of multiple data sources have been part of travel survey processes for some time. In the current context, where technologies and information systems spread and become more and more diverse, the transportation community is getting more and more interested in the potential of data fusion processes to help gather more complete datasets and help give additional utility to available data sources. Research is looking for ways to enhance the available information by using both various data collection methods and data from various sources, surveys or observation systems. Survey response rates are decreasing over the world, and combining survey modes appears to be an interesting way to address this problem. Letting interviewees choose their survey mode allows increasing response rates, but survey mode could impact the data collected. This paper first discusses issues rising when combining survey modes within the same survey and presents a method to merge the data coming from different survey modes, in order to consolidate the database. Then, it defines and describes the data fusion process and discusses how it can be relevant for transportation analysis and modelling purposes. Benefiting from the availability of various datasets from the Greater Montréal Area and the Greater Lyon Area, some applications of data fusion are constructed and/or reproduced to illustrate and test some of the methods described in the literature.

Details

Transport Survey Methods
Type: Book
ISBN: 978-1-84-855844-1

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Article
Publication date: 10 December 2019

Yeping Peng, Ghasem Bahrami, Hossein Khodadadi, Alireza Karimi, Ahmad Soleimani, Arash Karimipour and Sara Rostami

The purpose of this study is simulation of of polymer electrolyte membrane fuel cell. Proton-exchange membrane fuel cells are promising power sources for use in power plants and…

231

Abstract

Purpose

The purpose of this study is simulation of of polymer electrolyte membrane fuel cell. Proton-exchange membrane fuel cells are promising power sources for use in power plants and vehicles. These fuel cells provide a high level of energy efficiency at low temperature without any pollution. The convection inside the cell plays a key role in the electrochemical reactions and the performance of the cell. Accordingly, the transport processes in these cells have been investigated thoroughly in previous studies that also carried out functional modeling.

Design/methodology/approach

A multi-phase model was used to study the limitations of the reactions and their impact on the performance of the cell. The governing equations (conservation of mass, momentum and particle transport) were solved by computational fluid dynamics (CFD) (ANSYS fluent) using appropriate source terms. The two-phase flow in the fuel cell was simulated three-dimensionally under steady-state conditions. The flow of water inside the cell was also simulated at high-current density.

Findings

The simulation results suggested that the porosity of the gas diffusion layer (GDL) is one of the most important design parameters with a significant impact on the current density limitation and, consequently, on the cell performance.

Originality/value

This study was mainly focused on the two-phase analysis of the steady flow in the fuel cell and on investigating the impacts of a two-phase flow on the performance of the cell and also on the flow in the GDL, the membrane and the catalyst layer using the CFD.

Details

International Journal of Numerical Methods for Heat & Fluid Flow, vol. 30 no. 1
Type: Research Article
ISSN: 0961-5539

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Article
Publication date: 13 December 2019

Huawei Wu, Peyman Torkian, Amir Zarei, Iman Moradi, Arash Karimipour and Masoud Afrand

This paper aims to investigate atoms type and channel roughness effects on fluid behavior in nanochannel.

143

Abstract

Purpose

This paper aims to investigate atoms type and channel roughness effects on fluid behavior in nanochannel.

Design/methodology/approach

The results of mechanical properties of these structures are reported in this work by using molecular dynamics method.

Findings

The results show that nanochannel roughness is a limiting factor in flowing fluid in nanochannel. Moreover, fluids with less atomic weight have more free movement in ideal and non-ideal nanochannels.

Originality/value

For the study of mechanical properties of fluid/nanochannel system, the authors calculated parameters such as potential energy, density, temperature and velocity profiles of simulated fluids.

Details

International Journal of Numerical Methods for Heat & Fluid Flow, vol. 30 no. 1
Type: Research Article
ISSN: 0961-5539

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Article
Publication date: 16 June 2021

Chuloh Jung, Jihad Awad, Naglaa Sami Abdelaziz Mahmoud and Muna Salameh

This study aims to evaluate The Springs’ indoor environment, one of the iconic townhouse-type residential buildings in Dubai, more efficiently for the integrated evaluation of the…

306

Abstract

Purpose

This study aims to evaluate The Springs’ indoor environment, one of the iconic townhouse-type residential buildings in Dubai, more efficiently for the integrated evaluation of the indoor environment with the weights of indoor environmental factors such as thermal, indoor air, lighting and acoustic.

Design/methodology/approach

The weights of the indoor environment factors were derived for the integrated evaluation to reflect the residents’ preferences. Based on the post-occupancy evaluation (P.O.E.) survey, the weights according to the gender, age group and indoor spaces followed a comparison and analytical processes.

Findings

This paper had found the priority of residents’ needs for each space in The Springs project. In summer, thermal comfort was the most important factor for living room and the master bedroom. In winter, the priority for living room and kitchen was the indoor air quality.

Research limitations/implications

As it is the first research survey for housing project in Dubai, it needs to be extended to other housing projects in Dubai. To increase the reliability of the weights calculated through this study and the applicability of the integrated indoor environmental evaluation, more in-depth P.O.E. survey is needed with wide range of survey participants.

Social implications

This paper will help developing guidelines for future renovation based on the comparative analysis among thermal comfort, acoustic comfort, lighting comfort and indoor air comfort.

Originality/value

This paper is the first attempt to analyze the condition of early housing projects in Dubai. The data can be used to increase not only the design quality and marketability of housing projects in Dubai but also the condition of residents’ health status to avoid sick building syndrome from approximately 20 years old buildings.

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Article
Publication date: 13 June 2019

Zhe Tian, Seyed Amin Bagherzadeh, Kamal Ghani, Arash Karimipour, Ali Abdollahi, Mehrdad Bahrami and Mohammad Reza Safaei

This paper aims to propose a new nonlinear function estimation fuzzy system as a novel statistical approach to estimate nanofluids’ thermal conductivity.

122

Abstract

Purpose

This paper aims to propose a new nonlinear function estimation fuzzy system as a novel statistical approach to estimate nanofluids’ thermal conductivity.

Design/methodology/approach

A fuzzy system having a product inference engine, a singleton fuzzifier, a center average defuzzifier and Gaussian membership functions is proposed for this purpose.

Findings

Results indicate that the proposed fuzzy system can predict the thermal conductivity of Al2O3/paraffin nanofluid with appropriate precision and generalization and it also outperforms the classic interpolation methods.

Originality/value

A new nonlinear function estimation fuzzy system was introduced as a novel statistical approach to estimate nanofluids’ thermal conductivity for the first time.

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: 4 December 2018

Marjan Goodarzi, Saeed Javid, Ali Sajadifar, Mehdi Nojoomizadeh, Seyed Hossein Motaharipour, Quang-Vu Bach and Arash Karimipour

With respect to two new subjects, i.e. nanofluids and microchannels, in heat transfer systems and modern techniques used for building them, this paper aims to study on effect of…

227

Abstract

Purpose

With respect to two new subjects, i.e. nanofluids and microchannels, in heat transfer systems and modern techniques used for building them, this paper aims to study on effect of using aluminum oxide nanoparticles in non-Newtonian fluid of aqueous solution of carboxy-methyl cellulose in microtube and through application of different slip coefficients to achieve various qualities on surface of microtube.

Design/methodology/approach

Simultaneously, the effect of presence of nanoparticles and phenomenon of slip and temperature jump has been explored in non-Newtonian nanofluid in this essay. The assumption of homogeneity of nanofluid and fixed temperature of wall in microtube has been used in modeling processes.

Findings

The results have been presented as diagrams of velocity, temperature and Nusselt Number and the investigations have indicated that addition of nanoparticles to the base fluid and increase in microtube slip coefficient might improve rate of heat transfer in microtube.

Originality/value

The flow of non-Newtonian nanofluid of aqueous solution of carboxy methyl cellulose-aluminum oxide has been determined in a microtube for the first time.

Details

International Journal of Numerical Methods for Heat & Fluid Flow, vol. 29 no. 5
Type: Research Article
ISSN: 0961-5539

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Article
Publication date: 22 November 2018

Esmaeil Jalali and Arash Karimipour

In this paper, the forced convection heat transfer of the nanofluid composed of water and AL2O3 nanoparticles is simulated in a two-dimensional horizontal microchannel by…

174

Abstract

Purpose

In this paper, the forced convection heat transfer of the nanofluid composed of water and AL2O3 nanoparticles is simulated in a two-dimensional horizontal microchannel by injecting the lower wall. The upper wall of the microchannel is 303 K at temperature TH. On the lower wall of the microchannel, there are three holes for flow injection. Other parts of the wall are insulated. In this paper, the effect of parameters such as Reynolds number, slip coefficient and volume fraction of nanoparticles is investigated.

Design/methodology/approach

The boundary condition of the slip velocity is considered on the upper and lower walls of the microchannel. In this work, the flow of nanofluid in the microchannel is considered to be slow, permanent and Newtonian. In the present study, the effect of injection through the microchannel wall on the slip velocity is examined for the first time.

Findings

The results are also presented as velocity profiles and Nusselt number diagrams. It was found that the Nusselt number increases with increasing the amount of slip coefficient of velocity and the weight percentage of solid nanoparticles. The rate of this increase is higher in the high values of the Reynolds number.

Originality/value

A novel paper concerned the simulation of cross-flow injection effects on the slip velocity and temperature domain of a nanofluid flow inside a microchannel.

Details

International Journal of Numerical Methods for Heat & Fluid Flow, vol. 29 no. 5
Type: Research Article
ISSN: 0961-5539

Keywords

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