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Alternative Methods To Determine The Elastoplastic Properties Of Sintered Hydroxyapatite From Nanoindentation Testing Feb 2015

Alternative Methods To Determine The Elastoplastic Properties Of Sintered Hydroxyapatite From Nanoindentation Testing

Faculty of Engineering University of Malaya

This study introduces alternative methods to determine the elastoplastic properties of bovine-derived Hydroxyapatite (HA) porous bone graft through a set of nanoindentation tests with a Berkovich indenter. Generally, experimental data obtained from nanoindentation tests are force displacement, hardness and elastic modulus. However, to determine plastic properties such as strength coefficient and work hardening exponent of bovine HA, analytical or inverse finite element models are required. In this paper, the effect of sintering temperature on these properties of HA is studied for the range of 1000-1400 degrees C. The direct and inverse Finite Element (FE) simulation models for nanoindentation tests were ...


Nanomechanical Characterization Of Cavity Growth And Rupture In Hydrogen-Implanted Single-Crystal Batio3., Young-Bae Park, Patrick Nardi, Xiaodong Li, Harry A. Atwater Feb 2015

Nanomechanical Characterization Of Cavity Growth And Rupture In Hydrogen-Implanted Single-Crystal Batio3., Young-Bae Park, Patrick Nardi, Xiaodong Li, Harry A. Atwater

Xiaodong Li

A thermodynamic model of cavitynucleation and growth in ion-implanted single-crystal BaTiO3 layer is proposed, and cavity formation is related to the measured mechanical properties to better understand hydrogen implantation-induced layer transfer processes for ferroelectric thin films. The critical radius for cavitynucleation was determined experimentally from blistering experiments performed under isochronal anneal conditions and was calculated using continuum mechanical models for deformation and fracture, together with thermodynamic models. Based on thermodynamic modeling, we suggest that cavitiesgrow toward the cracking criteria at a critical blister size whereupon gas is emitted from ruptured cavities. The main driving force for layer splitting is the ...


Investigating The Surface Tribology Of Roller-Burnished Polymer Using The Fuzzy Rule-Based Approach Jan 2015

Investigating The Surface Tribology Of Roller-Burnished Polymer Using The Fuzzy Rule-Based Approach

Faculty of Engineering University of Malaya

Burnishing is specified as the plastic deformation cold working process applied as surface treatment and smoothing following machining to obtain a superior surface roughness finish. The present experimental study was carried out on roller-burnished polyurethane using a roller burnishing tool. An analysis was done to investigate the effect of burnishing depth, speed, feed rate, and roller width on the surface roughness of the polymer workpiece. Roughness (R-a) prediction was achieved with a fuzzy rule-based system. The results indicate 95% accuracy between the fuzzy predicted roughness values and experimental results. Link to Full-Text Articles : www.tandfonline.com/doi/abs/10.1080 ...


Surface Hardness Of Friction Stir Welded Aa6063 Pipe, Azman Ismail, Mokhtar Awang Jul 2014

Surface Hardness Of Friction Stir Welded Aa6063 Pipe, Azman Ismail, Mokhtar Awang

Azman Ismail

The external surface hardness of friction stir welded aluminum alloy 6063 pipe joint was investigated in this paper. The 89mm of outside diameter pipe with 5mm of wall thickness was used as test pipe piece for this experiment on closed butt joint configuration by utilising Bridgeport 2216 CNC milling machine and orbital clamping unit specially designed to cater for this task and function. Several welded samples were produced on varying process parameters which were successfully joined by using a non-consumable tool with a flat shoulder and a cylindrical pin.


Degradation Of Physical Properties Of Different Elastomers Upon Exposure To Palm Biodiesel Mar 2011

Degradation Of Physical Properties Of Different Elastomers Upon Exposure To Palm Biodiesel

A.S. Md Abdul Haseeb

Biodiesel, as an alternative fuel, is gradually receiving more popularity for use in internal combustion engines. However questions continue to arise with regard to its compatibility with elastomeric materials. The present work aims to investigate the comparative degradation of physical properties for different elastomers [e.g. ethylene propylene diene monomer (EPDM), silicone rubber (SR), polychloroprene (CR), polytetrafluroethylene (PTFE) and nitrile rubber (NBR)] upon exposure to diesel and palm biodiesel. Static immersion tests in B0(diesel), B10 (10% biodiesel in diesel), B20, B50 and B100(biodiesel) were carried out at room temperature (25 °C) for 1000 h. Different physical properties like ...


Addition Of Cobalt Nanoparticles Into Sn-3.8ag-0.7cu Lead-Free Solder By Paste Mixing Jan 2011

Addition Of Cobalt Nanoparticles Into Sn-3.8ag-0.7cu Lead-Free Solder By Paste Mixing

A.S. Md Abdul Haseeb

Purpose - The purpose of this paper is to investigate the effects of addition Co nanoparticles on the characteristic properties of Sn-3.8Ag-0.7Cu solder. Design/methodology/approach - Cobalt (Co) nanoparticles were added to Sn-Ag-Cu solders by thoroughly blending various weight percentages (0-2.0 wt%) of Co nanoparticles with near eutectic SAC387 solder paste. Blending was done mechanically for 30 min to ensure a homogeneous mixture. The paste mixture was then reflowed on a hot plate at 250°C for 45 s. The melting points of nanocomposite solder were determined by differential scanning calorimetry. Spreading rate of nanocomposite was calculated following ...


Structural And Mechanical Properties Of Nanostructured Tio2 Thin Films Deposited By Rf Sputtering Oct 2010

Structural And Mechanical Properties Of Nanostructured Tio2 Thin Films Deposited By Rf Sputtering

A.S. Md Abdul Haseeb

This study mainly aims to evaluate the effects of substrate temperatures on the mechanical properties of TiO2 thin films deposited on glass substrates by radio-frequency (RF) magnetron sputtering. All titania films possess anatase structure having a nodular morphology. AES results reveal that Si and Na ions from glass diffuse into TiO2 films at higher substrate temperatures. Micro-scratch and wear tests were conducted to evaluate their mechanical and tribological properties. The adhesion critical loads of TiO2 films deposited at room temperature, 200 and 300°C are found to be 1.51, 1.54 and 1.08N, respectively. Scratch hardness also increases ...


Compatibility Of Elastomers In Palm Biodiesel Oct 2010

Compatibility Of Elastomers In Palm Biodiesel

A.S. Md Abdul Haseeb

In recent time, environmental awareness and concern over the rapid exhaustion of fossil fuels have led to an increased popularity of biodiesel as an alternative fuel for automobiles. However, there are concerns over enhanced degradation of automotive materials in biodiesel. The present study aims to investigate the impact of palm biodiesel on the degradation behavior of elastomers such as nitrile rubber (NBR), polychloroprene, and fluoro-viton A. Static immersion tests in B0 (diesel), B10 (10% biodiesel in diesel), B100 (biodiesel) were carried out at room temperature (25 °C) and at 50 °C for 500 h. At the end of immersion test ...


Thermal Stability Of Electrodeposited Liga Ni-W Alloys For High Temperature Mems Applications Jan 2008

Thermal Stability Of Electrodeposited Liga Ni-W Alloys For High Temperature Mems Applications

A.S. Md Abdul Haseeb

For thermally stable LIGA materials for high temperature MEMS applications LIGA Ni-W layers and micro testing samples with different compositions (15 and 5 at% W) were electrodeposited. In order to investigate the thermal stability the Ni-W layers were annealed at different temperatures (300-700°C) and for different durations (1, 4, 16 h). Their microstructure and micro-hardness were than analysed after annealing and compared with those of as-deposited states. The observed microstructures show, in comparison to pure LIGA nickel, a small grain growth and a relatively stable structure up to 700°C. The micro-hardness values of the LIGA Ni-W layers are ...


On The Nature Of The Electrochemically Synthesized Hard Fe-0.96 Mass Pct C Alloy Film Dec 2002

On The Nature Of The Electrochemically Synthesized Hard Fe-0.96 Mass Pct C Alloy Film

A.S. Md Abdul Haseeb

A hard Fe-0.96 mass pet C alloy with a hardness value of 810 HV has been electrochemically synthesized from a ferrous sulfate bath containing a small amount of citric acid and L-ascorbic acid. The nature of the alloy has been investigated by a number of techniques, including X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), transmission electron microscopy (TEM), Mössbauer spectroscopy, differential scanning calorimetry (DSC), and magnetic measurements. The decomposition behavior of the alloy is also studied and compared with that of thermally prepared martensite. It has been found that the electrochemically deposited Fe-C alloy exists ...


On The Nature Of The Electrochemically Synthesized Hard Fe-0.96 Mass Pct C Alloy Film Nov 2002

On The Nature Of The Electrochemically Synthesized Hard Fe-0.96 Mass Pct C Alloy Film

A.S. Md Abdul Haseeb

A hard Fe-0.96 mass pet C alloy with a hardness value of 810 HV has been electrochemically synthesized from a ferrous sulfate bath containing a small amount of citric acid and L-ascorbic acid. The nature of the alloy has been investigated by a number of techniques, including X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), transmission electron microscopy (TEM), Mössbauer spectroscopy, differential scanning calorimetry (DSC), and magnetic measurements. The decomposition behavior of the alloy is also studied and compared with that of thermally prepared martensite. It has been found that the electrochemically deposited Fe-C alloy exists ...


Study Of The Wear Behaviour Of Al-4.5% Cu-3.4% Fe In Situ Composite: Effect Of Thermal And Mechanical Processing Aug 1995

Study Of The Wear Behaviour Of Al-4.5% Cu-3.4% Fe In Situ Composite: Effect Of Thermal And Mechanical Processing

A.S. Md Abdul Haseeb

Wear behaviour of as-cast and heat-treated spheroidal graphite (SG) cast iron has been studied under dry sliding conditions using a pin-on-disc type apparatus. Wear tests were carried out at a linear sliding speed of 0.88 m s -1, under a constant load of 1.5 kg. All tests were performed in ambient air at room temperature. Extent of wear damage and wear mechanisms were investigated by means of weight loss measurement, optical microscopy, microhardness measurement and X-ray diffractometry on wear debris. The wear rate measured after 9500 m of sliding is found to be about three times higher in ...