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Article
Publication date: 1 October 2004

Jaw‐Ren Lin, Rong‐Fang Lu and Won‐Hsion Liao

The analysis of squeeze‐film performances between curved annular plates with an electrically conducting fluid in the presence of a transverse magnetic field is presented…

Abstract

The analysis of squeeze‐film performances between curved annular plates with an electrically conducting fluid in the presence of a transverse magnetic field is presented in this study. The magneto‐hydrodynamic (MHD) Reynolds‐type equation for squeezing‐film curved annular disks is derived using the continuity equation and the MHD motion equations. A closed‐form solution for the squeezing film pressure is obtained, and applied to predict the MHD squeeze‐film characteristics. According to the results obtained, the presence of applied magnetic fields signifies an increase in the MHD squeeze‐film pressure. Compared with the classical non‐conducting‐lubricant case, the magnetic‐field effect characterized by the Hartmann number provides an enhancement to the MHD load‐carrying capacity and the response time, especially for larger values of the curved shape parameter or smaller values of inner‐outer radius ratio of the curved annular disks.

Details

Industrial Lubrication and Tribology, vol. 56 no. 5
Type: Research Article
ISSN: 0036-8792

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Article
Publication date: 27 June 2019

Ereny Gobrial

Children and young people with comorbid intellectual disabilities (ID) and autism spectrum disorders (ASD) are more likely to exhibit comorbid mental health disorders (MHD

Abstract

Purpose

Children and young people with comorbid intellectual disabilities (ID) and autism spectrum disorders (ASD) are more likely to exhibit comorbid mental health disorders (MHD) and other significant behaviours (SB) in addition to the core symptoms of ASD. The purpose of this paper is to identify the prevalence of comorbid MHD and behaviours in children and young people with ID and ASD in Egypt.

Design/methodology/approach

The Reiss scale for children’s dual diagnosis was administered by parents and teachers of 222 Egyptian children and young people with mild/moderate ID and ASD to screen for MHD and SB. The mean age of children and young people was 12.3 years (SD = 3.64), with 75.6 per cent male.

Findings

The results revealed that 62.2 per cent of children and young people with ID and ASD had high rates of comorbid MHD and behaviour disorders were shown in 64.4 per cent of the participated children and young people. The results identified anger, anxiety and psychosis being the most frequently diagnosed disorders while crying spells and pica were the most SB. No differences were found between the male and female with ID and ASD in the current study.

Research limitations/implications

Mental health assessment of children and young people with ID and ASD will help to highlight the needs of these vulnerable children and develop the appropriate services.

Originality/value

The findings highlight the prevalence of MHD in children and young people with ID and ASD in Egypt. This has implications on the assessment of comorbid disorders and services needed for children with ID and ASD in Egypt.

Details

Advances in Mental Health and Intellectual Disabilities, vol. 13 no. 5
Type: Research Article
ISSN: 2044-1282

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Article
Publication date: 19 September 2016

Yue Ji, Xingfei Li, Tengfei Wu, Cheng Chen and Ying Yang

The evaluations of the magnetohydrodynamics angular rate sensor (MHD ARS) in its applications necessitate further improvements in the sensor’s dynamic measurement ability…

Abstract

Purpose

The evaluations of the magnetohydrodynamics angular rate sensor (MHD ARS) in its applications necessitate further improvements in the sensor’s dynamic measurement ability. The magnetic field of the MHD ARS is a key factor in the sensor’s modeling and error analysis. The aim of this study is to illustrate the influence of a non-uniform magnetic field on the sensor.

Design/methodology/approach

Numerical simulation is made using ANSYS FLUNET with the magnetic field calculated by 3D-Magnetostatic. The comparison of the simulation results between uniform and non-uniform magnetic fields is made to reveal and explain the effects of magnetic field inhomogeneity (MFI) on the flow and electric field in detail. Two different structures with different MFIs are designed to confirm the MFI effect on the sensor’s output in simulation and experiment. A cross-correlation experiment and an adaptive filter are carried out to extract the signal to identify the error of the sensor output caused by MFI.

Findings

The MFI effect on the flow field in MHD ARS is found to be insignificant, while its effect on the electric potential is considerable. The comparisons between two kinds of MHD ARS in numerical simulation and experiment show that the MFI effect on the sensor error can be identified by fitting the sensor output. The deviation is mainly generated at the peaks and valleys of an angular vibration.

Originality/value

The study of the MHD ARS under the influence of a non-uniform magnetic field can offer an understanding of the MFI effect on the sensor and an evaluation method of the sensor error caused by the MFI effect.

Details

Sensor Review, vol. 36 no. 4
Type: Research Article
ISSN: 0260-2288

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Article
Publication date: 1 January 2013

GholamReza Kefayati, Mofid Gorji, Hasan Sajjadi and Davood Domiri Ganji

Magneto hydrodynamic (MHD) flows in fluids is known to have an important effect on heat transfer and fluid flow in various substances while the quality of the substances…

Abstract

Purpose

Magneto hydrodynamic (MHD) flows in fluids is known to have an important effect on heat transfer and fluid flow in various substances while the quality of the substances and the considered shapes can influence the amount of changes. Thus, MHD flows in a different form and widespread alterations in the kind of the material and the power of MHD flow were carried out by lattice Boltzmann method (LBM) in this investigation. The aim of this paper is to identify the ability of LBM for solving MHD flows as the effect of different substances in the presence of the magnetic field changes.

Design/methodology/approach

This method was utilized for solving MHD natural convection in an open cavity while Hartmann number varies from 0 to 150 and Rayleigh number is considered at values of Ra=103, 104 and 105, with the Prandtl number altering in a wide range of Pr=0.025, 0.71 and 6.2. An appropriate validation with previous numerical investigations demonstrated that this attitude is a suitable method for MHD problems.

Findings

Results show the alterations of Prandtl numbers influence the isotherms and the streamlines widely at different Rayleigh and Hartmann numbers simultaneously. Moreover, heat transfer declines with the increment of Hartmann number, while this reduction is marginal for Ra=103 by comparison with other Rayleigh numbers. The effect of the magnetic field on the average Nusselt number at Liquid Gallium (Pr=0.025) is the least among considered materials.

Originality/value

In this method, just the force term at LBM changes in the presence of MHD flow as the added term rises from the classic equations of fluids mechanic. Moreover, all parameters of the added term and the method of their computing are exhibited.

Details

Engineering Computations, vol. 30 no. 1
Type: Research Article
ISSN: 0264-4401

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Article
Publication date: 8 April 2014

Neminath Bhujappa Naduvinamani and Mareppa Rajashekar

The purpose of this article is to analyse the effects of surface roughness on the magneto-hydrodynamic (MHD) squeeze-film characteristics between a sphere and a porous…

Abstract

Purpose

The purpose of this article is to analyse the effects of surface roughness on the magneto-hydrodynamic (MHD) squeeze-film characteristics between a sphere and a porous plane surface, which have not been studied so far.

Design/methodology/approach

The analytical model takes into account the effect of porosity by assuming that the flow in the porous matrix obeys modified Darcy's law. The stochastic MHD Reynold's type equation is derived by using the Christensen's stochastic method developed for hydrodynamic lubrication of rough surfaces. Two types of one-dimensional surface roughness (radial and azimuthal) patterns are considered.

Findings

The expressions for the mean MHD squeeze-film pressure and mean load-carrying capacity are obtained numerically. The results are shown graphically for selected representative parametric values. It is found that the response time increases significantly for the MHD case as compared to the corresponding non-conducting lubricants. The effect of roughness parameter is to increase/decrease the load-carrying capacity and the response time for azimuthal/radial roughness patterns as compared to the smooth case. Also, the effect of porous parameter is to decrease the load-carrying capacity and response time as compared to the solid case.

Originality/value

In this paper, an attempt has been made to analyse the combined effects of surface roughness and permeability on the MHD squeeze-film characteristics between a sphere and a plane surface.

Details

Industrial Lubrication and Tribology, vol. 66 no. 3
Type: Research Article
ISSN: 0036-8792

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Article
Publication date: 20 February 2017

Kellie Buckley-Walker, Trevor P. Crowe and Peter Caputi

Caring for a person with a substance use disorder (SUD) and/or mental health disorder (MHD) represents a significant burden for family members. The features of…

Abstract

Purpose

Caring for a person with a substance use disorder (SUD) and/or mental health disorder (MHD) represents a significant burden for family members. The features of “carers/family members” experiences reflect trauma signatures. Consequently, working through this trauma for carers corresponds with psychological recovery, empowerment processes and intrapersonal/interpersonal needs. The purpose of this paper is to outline a framework called the “personal and relational empowerment (PRE)” framework which enables family support practitioners to help family members to be able to take control of their own lives, develop meaningful relationships and live purposeful and fulfilling lives, regardless of whether the person with the SUD and/or MHD is in recovery or not.

Design/methodology/approach

This paper critically reviews existing frameworks for carer recovery, through a systematic literature search, and proposes a “PRE” alternative to redress the shortfalls in these existing frameworks.

Findings

The PRE framework takes a multi-level needs-based approach to understand carer recovery. This framework links the concepts – psychological recovery, empowerment processes and intrapersonal/interpersonal needs.

Practical implications

The PRE framework recognises the importance of recovery support practitioners being able to balance the immediate carer crisis intervention needs responses with personal growth and well-being supporting interventions.

Originality/value

The PRE framework of family recovery attempts to answer the need to broaden the focus on the family journey to better reflect the principles and practices of contemporary SUD and/or MHD recovery-based support.

Details

Advances in Dual Diagnosis, vol. 10 no. 1
Type: Research Article
ISSN: 1757-0972

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Article
Publication date: 28 July 2020

Mouhcine Mouda, Mohamed Nabhani and Mohamed El Khlifi

The purpose of this paper is to examine the effect of surface roughness on the magneto-hydrodynamic (MHD) non-parallel squeeze film lubrication using non-Newtonian lubricant.

Abstract

Purpose

The purpose of this paper is to examine the effect of surface roughness on the magneto-hydrodynamic (MHD) non-parallel squeeze film lubrication using non-Newtonian lubricant.

Design/methodology/approach

Based on the MHD thin film lubrication theory and the Stokes theory and homogenization method, the homogenized MHD Reynolds equation is derived considering the squeezing effect.

Findings

It is found that the obtained results indicate that the interaction among non-Newtonian, MHD and surface roughness influences is significant.

Originality/value

This study is original which compares the dimensionless load capacity and dimensionless response time among transverse, longitudinal and, for the first time, anisotropic surface roughness types under magneto-hydrodynamic non-Newtonian non-parallel squeeze film lubrication.

Peer review

The peer review history for this article is available at: https://publons.com/publon/10.1108/ILT-02-2020-0071/

Details

Industrial Lubrication and Tribology, vol. 73 no. 1
Type: Research Article
ISSN: 0036-8792

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Article
Publication date: 28 April 2020

Umair Rashid and Haiyi Liang

In this article, we consider the magnetohydrodynamic (MHD) nanofluid flow over a rotating stretchable disk through porous medium. For porous medium, Darcy’s relation is…

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Abstract

Purpose

In this article, we consider the magnetohydrodynamic (MHD) nanofluid flow over a rotating stretchable disk through porous medium. For porous medium, Darcy’s relation is used. It also encompassed the impact of nanoparticles shape on MHD nanofluid flow and heat transfer. The effect of thermal radiation and Joule heating is also being considered.

Design/methodology/approach

Three categories of nanoparticles are taken into deliberation, i.e. copper, silver and titanium oxide. The nanofluid is made of pure water and various types of sphere- and lamina-shaped nanoparticles. By using appropriate similarity transformation, the governing partial differential equations are transformed to ordinary one. The coupled ordinary differential equations system is tackled numerically by bvp4c method.

Findings

The impact of various pertinent parameters, i.e. solid volume fraction, Hartman number, thermal radiations parameter, Reynolds number, Eckert number, porosity parameter and ratio parameter, on flow and Nusselt number with a fixed value of Prandtl number at 6.2 is discussed in details. The obtained results are presented in the concluding section. The lamina shape of nanoparticles in silver-water performed an excellent role on temperature distribution. The heat transfer rate of lamina shape in copper-water was found to be greater in the system of flow regime.

Originality/value

The authors have discussed the shape effect of nanoparticles on MHD nanofluid flow over a rotating stretchable disk through porous medium using three categories of nanoparticles, such as copper, silver and titanium oxide. To the best of the authors’ knowledge, this is the first study on mass and heat transfer nanofluid flow and no such study is yet published in literature. A detailed mathematical analysis has also to be carried out to prove the regularity of model. The authors believe that the numerical results are original and have not been copied from any other sources.

Details

International Journal of Numerical Methods for Heat & Fluid Flow, vol. 30 no. 12
Type: Research Article
ISSN: 0961-5539

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Article
Publication date: 28 April 2020

Jinting Yang and Tong Zhang

The purpose of this paper is to propose three iterative finite element methods for equations of thermally coupled incompressible magneto-hydrodynamics (MHD) on 2D/3D…

Abstract

Purpose

The purpose of this paper is to propose three iterative finite element methods for equations of thermally coupled incompressible magneto-hydrodynamics (MHD) on 2D/3D bounded domain. The detailed theoretical analysis and some numerical results are presented. The main results show that the Stokes iterative method has the strictest restrictions on the physical parameters, and the Newton’s iterative method has the higher accuracy and the Oseen iterative method is stable unconditionally.

Design/methodology/approach

Three iterative finite element methods have been designed for the thermally coupled incompressible MHD flow on 2D/3D bounded domain. The Oseen iterative scheme includes solving a linearized steady MHD and Oseen equations; unconditional stability and optimal error estimates of numerical approximations at each iterative step are established under the uniqueness condition. Stability and convergence of numerical solutions in Newton and Stokes’ iterative schemes are also analyzed under some strong uniqueness conditions.

Findings

This work was supported by the NSF of China (No. 11971152).

Originality/value

This paper presents the best choice for solving the steady thermally coupled MHD equations with different physical parameters.

Details

International Journal of Numerical Methods for Heat & Fluid Flow, vol. 30 no. 12
Type: Research Article
ISSN: 0961-5539

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Article
Publication date: 9 October 2019

Bidemi Olumide Falodun and Adeola John Omowaye

This paper aims to address the problem of double-diffusive magnetohydrodynamics (MHD) non-Darcy convective flow of heat and mass transfer over a stretching sheet embedded…

Abstract

Purpose

This paper aims to address the problem of double-diffusive magnetohydrodynamics (MHD) non-Darcy convective flow of heat and mass transfer over a stretching sheet embedded in a thermally-stratified porous medium. The controlling parameters such as chemical reaction parameter, permeability parameter, etc., are extensively discussed and illustrated in this paper.

Design/methodology/approach

With the help of appropriate similarity variables, the governing partial differential equations are converted into ordinary differential equations. The transformed equations are solved using the spectral homotopy analysis method (SHAM). SHAM is a numerical method, which uses Chebyshev pseudospectral and homotopy analysis method in solving science and engineering problems.

Findings

The effects of all controlling parameters are presented using graphical representations. The results revealed that the applied magnetic field in the transverse direction to the flow gives rise to a resistive force called Lorentz. This force tends to reduce the flow of an electrically conducting fluid in the problem of heat and mass transfer. As a result, the fluid velocity reduces in the boundary layer. Also, the suction increases the velocity, temperature, and concentration of the fluid, respectively. The present results can be used in complex problems dealing with double-diffusive MHD non-Darcy convective flow of heat and mass transfer.

Originality/value

The uniqueness of this paper is the examination of double-diffusive MHD non-Darcy convective flow of heat and mass transfer. It is considered over a stretching sheet embedded in a thermally-stratified porous medium. To the best of the knowledge, a problem of this type has not been considered in the past. A novel method called SHAM is used to solve this modelled problem. The novelty of this method is its accuracy and fastness in computation.

Details

World Journal of Engineering, vol. 16 no. 6
Type: Research Article
ISSN: 1708-5284

Keywords

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