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Thermal stress analysis of dry friction clutches
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Purpose

The purpose of this paper is to present an approach to compute accurately the distributions of the frictional heat generated, contact pressure and thermal stresses at any instant during the sliding period (heating phase) of the single-disc friction clutch system works in the dry condition and the complex interaction among them.

Design/methodology/approach

Numerical work was achieved using the developed elastic and thermal finite element models (axisymmetric models) to simulate the engagement of the single-disc friction clutch system.

Findings

The change of distribution of contact pressure during the sliding period (heating phase) affects significantly the magnitude and distribution of the produced thermal stress. The high local heat generated appeared in the contacting surfaces because of the non-uniformity of the distribution of contact pressure during the heating phase (sliding time) and this will dramatically increase the thermal stresses.

Originality/value

Sequentially coupled thermal-mechanical approach was developed to investigate the thermal stresses problem in automotive clutches under dry conditions. This approach is considered a promising approach to investigate the effect of material, sliding time, torque function, etc., on the thermal stresses of different types of friction clutch.

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Publication Date
Sun Apr 08 2018
Journal Name
Al-khwarizmi Engineering Journal
Microstructural Characterization and Mechanical Properties of Similar and Dissimilar Al Alloys Joined using Friction Stir Welding
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The influence of pre- shot peening and welding parameters on mechanical and metallurgical properties of dissimilar and similar aluminum alloys AA2024-T3 and AA6061-T6 joints using friction stir welding have been studied. In this work, numbers of plates were equipped from sheet alloys in dimensions (150*50*6) mm then some of them were exposed to shot peening process before friction stir welding using steel ball having diameter 1.25 mm for period of 15 minutes. FSW joints were manufactured from plates at three welding speeds (28, 40, 56 mm/min) and welding speed 40mm/min was chosen at a rotating speed of 1400 rpm for welding the dissimilar pre- shot plates. Tow joints were made at rotational speed of 1000 rpm and welding speed of 40m/min f

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Publication Date
Thu May 11 2023
Journal Name
Engineering Applications Of Computational Fluid Mechanics
Photovoltaic-thermal system combined with wavy tubes, twisted tape inserts and a novel coolant fluid: energy and exergy analysis
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To create a highly efficient photovoltaic-thermal (PV-T) system and maximise the energy and exergy efficiency, this study aims to propose an innovative configuration of a PV-T system comprising wavy tubes with twisted-tape inserts. Following the validation of a numerical model, a parametric study has been conducted to assess the geometrical effects of twisted tape and wavy tubes, as well as the coolant fluid type and velocity, on the overall performance of a PV-T system, located in Shiraz, Iran. It is found that employing twisted tape improves the energy and exergy efficiency by approx. 6.3%. The best configuration yields 12.4% and 16.8% increase in energy and exergy efficiency compared to conventional PV systems. This is achieved at 15% vo

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Publication Date
Thu Jun 01 2023
Journal Name
Baghdad Science Journal
Mn(II),Fe(III),Co(II)and Rh(III) complexes with azo ligand: Synthesis, characterization, thermal analysis and bioactivity
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New series of metal ions complexes have been prepared from the new ligand [4-Amino-N-(5-methyl-isaxazol-3-yl)-benzenesulfonamide] derived from Sulfamethoxazole and 3-aminophenol. Accordingly, mono-nuclear Mn(II), Fe(III), Co (II), and Rh(III) complexes were prepared by the reaction of previous ligand with MnCl2.4H2O, CoCl2.6H2O, FeCl3.6H2O and RhCl3H2O, respectively. The compounds have been characterized by Fourier-transform infrared (FTIR), ultraviolet–visible (UV–vis), mass,  1H-, and 13C-nuclear magnetic resonance (NMR) spectra and thermo gravimetric analysis (TGA& DSC) curve, Bohr magnetic (B.M.), elemental microanal

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Publication Date
Fri Apr 21 2023
Journal Name
Aip Conference Proceedings
Study the contrast of thermal expansion behavior for PMMA denture base, single and hybrid reinforced using the thermomechanical analysis technique (TMA)
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This research investigated the effect of adding two groups of reinforcement materials, including bioactive materials Hydroxyapatite (HA) and halloysite nanoclay and bioinert materials Alumina (AL2O3) and Zirconia (ZrO2), each of them with various weight ratios (1,2,3,4 &5)% to the polymer matrix PMMA. The best ratios were selected, and then a hybrid was preparing Composite red from the best ratios from each group. Thermal properties, including thermal conductivity and Thermomechanical Analysis (TMA) technology, have been studied. The results showed that adding 3% Hydroxyapatite (HA) and 5% halloysite nanoclay to the polymethacrylate (PMMA) mer leads to an increase in thermal conductivity. It was also found from the Thermomechanical Analysis

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Publication Date
Sun Jan 01 2023
Journal Name
Technologies And Materials For Renewable Energy, Environment And Sustainability: Tmrees22fr
Study the contrast of thermal expansion behavior for PMMA denture base, single and hybrid reinforced using the thermomechanical analysis technique (TMA)
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Publication Date
Wed Apr 25 2018
Journal Name
Earthquake And Structures
Response of circular footing on dry dense sand to impact load with different embedment depths
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Scopus
Publication Date
Thu Aug 27 2020
Journal Name
European Journal Of Ophthalmology
Comparison of corneal epithelial thickness profile in dry eye patients, keratoconus suspect, and healthy eyes
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Purpose:

To compare the corneal epithelial thickness profile in patients with dry eyes and keratoconus suspect with normal healthy eyes.

Methods:

The study involved 120 eyes with an age range from 19 to 30 years. Forty eyes had normal corneal topography and no dry eyes. Forty eyes had dry eyes but had normal corneal topography. The last 40 eyes were keratoconus suspect and had no symptoms or signs of dry eyes.

Results:

Central epithelial thickness was not different statistically for all eyes. ( p-value: 0.1). The superior epithelial thickness was 53.5 µm ±3.1 in the control

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Publication Date
Mon Jun 01 2015
Journal Name
Journal Of Engineering
Using Nanoparticles for Enhance Thermal Conductivity of Latent Heat Thermal Energy Storage
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Phase change materials (PCMs) such as paraffin wax can be used to store or release large amount of energy at certain temperature at which their solid-liquid phase changes occurs. Paraffin wax that used in latent heat thermal energy storage (LHTES) has low thermal conductivity. In this study, the thermal conductivity of paraffin wax has been enhanced by adding different mass concentration (1wt.%, 3wt.%, 5wt.%) of (TiO2) nano-particles with about (10nm) diameter. It is found that the phase change temperature varies with adding (TiO2) nanoparticles in to the paraffin wax. The thermal conductivity of the composites is found to decrease with increasing temperature. The increase in thermal conductivity ha

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Publication Date
Sat Oct 01 2022
Journal Name
Journal Of Engineering
Numerical Study of Thermal Conductivity Effect on The Performance of Thermal Energy Storage
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In this study, the effect of the thermal conductivity of phase change material (PCM) on the performance of thermal energy storage has been analyzed numerically. A horizontal concentric shell-and-tube latent heat thermal energy storage system (LHTESS) has been performed during the solidification process. Two types of paraffin wax with different melting temperatures and thermal conductivity were used as a PCM on the shell side, case1=0.265W/m.K and case2=0.311 W/m.K. Water has been used as heat transfer fluid (HTF) flow through in tube side. Ansys fluent has been used to analyze the model by taking into account phase change by the enthalpy method used to deal with phase transition. The numerical simulatio

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Publication Date
Mon Mar 27 2017
Journal Name
Iraqi Journal Of Pharmaceutical Sciences ( P-issn 1683 - 3597 E-issn 2521 - 3512)
Association of Oxidative Stress Markers with Cholelithiasis
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Oxidative stress markers are of important diagnostic parameters for many disorders including cholelithiasis. This present study has aimed to assess the state of oxidative stress in symptomatic radiographically confirmed (Cholelithiasis) patients by measuring two parameters used as oxidative stress parameters which are serum myeloperoxidase (MPO) and superoxide dismutase (SOD). This study was carried out on 100 patient diagnosed as (Cholelithiasis) patients with 30 age and sex matched healthy controls by measuring serum (MPO) and (SOD) by ELIZA technique .Results showed significantly decrease in antioxidant enzyme(SOD) and increase in serum level of (MPO) comparing with controls.

Keywords: Cholelithiasis , Oxidative stress

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