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Investigation About The Characterization Of Machine Tool Spindle Stiffness For Intelligent Cnc End Milling
Faculty of Engineering University of Malaya
This paper describes how to investigate the characterization of the machine tool spindle stiffness in radial direction for precise monitoring of cutting forces in end milling process by using displacement sensors. Four sensitive eddy-current displacement sensors are installed on the spindle housing of a machining center so that they can detect the radial motion of the rotating spindle. Thermocouples are also attached to the spindle structure, and the stability of the displacement sensing is examined. The change in spindle stiffness due to the spindle temperature and the speed is investigated. Finally, monitoring results of small and medium scale cutting forces …
Significantly Improved Photocurrent Response Of Zns-Reduced Graphene Oxide Composites
Significantly Improved Photocurrent Response Of Zns-Reduced Graphene Oxide Composites
Faculty of Engineering University of Malaya
ZnS-nanoparticles (NPs) reduced graphene oxide (rGO) composites with a high degree of crystallinity and high dispersity were successfully synthesized via a facile solvothermal method in the gelatin medium, during which the formation of ZnS NPs, reduction of graphene oxide and loading of ZnS NPs into the rGO surface occur simultaneously. Gelatin, as a natural capping agent, plays a significant role in controlling the degree of dispersion and coverage of ZnS NPs. The effect of rGO on the crystalline structure and optical properties of ZnS NPs were determined via X-ray diffraction, UV-visible diffused reflectance spectroscopy and photoluminescence spectroscopy. The ZnS-rGO composites …
Mechanical Properties Of Intermetallic Compounds In Electrodeposited Multilayered Thin Film At Small Scale By Nanoindentation
Faculty of Engineering University of Malaya
Mechanical properties of intermetallic compounds (IMCs) which were formed in electrodeposited Cu/Sn and Cu/Ni/Sn multilayered thin film have been investigated. The layers of Cu, Sn and Ni were formed by electrodeposition technique using copper pyrophosphate, tin methanesulfonic and nickel Watts baths, respectively. After synthesis, samples were subjected to high temperature aging at 150 degrees C for 168 h. Two different types of intermetallics Cu3Sn and Cu6Sn5 were formed in Cu/Sn. After adding ultra-thin layer of Ni (70 nm) in between Cu and Sn layers, (Cu, Ni)(6)Sn-5 was formed after aging at similar condition to that of Cu/Sn. Tin whisker growth …
Evaluating The Optical Properties Of Tio2 Nanofluid For A Direct Absorption Solar Collector
Evaluating The Optical Properties Of Tio2 Nanofluid For A Direct Absorption Solar Collector
Faculty of Engineering University of Malaya
Recent studies specify that designated nanofluids may increase the proficiency of direct absorption solar thermal collectors. To determine the efficiency of nanofluids in solar applications, their capability to change light energy to thermal energy must be identified (i.e., the absorption spectrum of the solar material). In view of that, this study compares model predictions to spectroscopic measurements of extinction coefficients over wavelengths that are important for solar energy (200- 1100nm). In the first decade of nanofluid research, most of the focus was on measuring and modeling the fundamental thermophysical properties of nanofluids (i.e., thermal conductivity, density, viscosity, and convection coefficients). …
Experimental And Numerical Investigation Of Heat Transfer In Cnt Nanofluids
Experimental And Numerical Investigation Of Heat Transfer In Cnt Nanofluids
Faculty of Engineering University of Malaya
Nanofluids with their enhanced thermal conductivity are believed to be a promising coolant in heat transfer applications. In this study, carbon nanotube (CNT) nanofluids of 0.01wt%, stabilised by 1.0wt% gum arabic were used as a cooling liquid in a concentric tube laminar flow heat exchanger. The flow rate of cold fluid varied from 10 to 50g/s. Both experimental and numerical simulations were carried out to determine the heat transfer enhancement using CNT nanofluids. Computational fluid dynamics (CFD) simulations were carried out using Fluent v 6.3 by assuming single-phase approximation. Thermal conductivity, density and rheology of the nanofluid were also measured …
The Use Of Initial Imperfection Approach In Design Process And Buckling Failure Evaluation Of Axially Compressed Composite Cylindrical Shells
Faculty of Engineering University of Malaya
Thin-walled cylindrical shells are susceptible to buckling failures caused by the axial compressive loading. During the design process or the buckling failure evaluation of axially-compressed cylindrical shells, initial geometric and loading imperfections are of important parameters for the analyses. Therefore, the engineers/designers are expected to well understand the physical behaviours of shell buckling to prevent unexpected serious failure in structures. In particular, it is widely reported that no efficient guidelines for modelling imperfections in composite structures are available. Knowledge obtained from the relevant works is open for updates and highly sought. In this work, we study the influence of imperfections …
A Review On Thermophysical Properties Of Nanoparticle Dispersed Phase Change Materials
A Review On Thermophysical Properties Of Nanoparticle Dispersed Phase Change Materials
Faculty of Engineering University of Malaya
A review of current experimental studies on variations in thermophysical properties of phase change material (PCM) due to dispersion of nanoparticles is presented in this article. Dispersed carbon nanotubes/fiber and different metal/metal oxide nano particles in paraffin and fatty acids might be a solution to improve latent heat thermal storage performance. Thermophysical properties such as thermal conductivity, latent heat, viscosity and super cooling of phase change materials (PCM) could be changed for different physical properties of dispersed nanoparticle such as size, shape, concentration and surface properties. Among the nano particles, comparatively carbon nanotubes and carbon nano fiber have shown better …
Isi Document Delivery No.: Ce6qq Times Cited: 0 Cited Reference Count: 44 Cited References: Adalberth K, 1997, Build Environ, V32, P321, Doi 10.1016/S0360-1323(96)00069-8 [Anonymous], 2005, E38405 Astm, P1 Arena Ap, 2003, Build Environ, V38, P359, Doi 10.1016/S0360-1323(02)00056-2 Asif M, 2007, Build Environ, V42, P1391, Doi 10.1016/J.Buildenv.2005.11.023 Attia S, 2011, State Art Existing E Bare Jc, 2000, Int J Life Cycle Ass, V5, P319, Doi 10.1007/Bf02978665 Blengini Ga, 2010, Energ Buildings, V42, P869, Doi 10.1016/J.Enbuild.2009.12.009 Blengini Ga, 2010, Int J Life Cycle Ass, V15, P652, Doi 10.1007/S11367-010-0190-5 Bribian Iz, 2009, Build Environ, V44, P2510, Doi 10.1016/J.Buildenv.2009.05.001 Buchan Rd, 2003, Estimating Builders Cole Rj, 1996, Build Environ, V31, P307, Doi 10.1016/0360-1323(96)00017-0 Cole Rj, 1999, Build Environ, V34, P335 Ding Gkc, 2007, Build Res Inf, V35, P487, Doi 10.1080/09613210601116408 Fava J, 2009, J Ind Ecol, V13, P491, Doi 10.1111/J.1530-9290.2009.00150.X Fay R, 2000, Build Res Inf, V28, P31 Goedkoop M, 2010, Intro To Lca Guinee Jb., 2002, Hdb Life Cycle Asses, P692 Han G, 2011, Life Cycle Assessmen Huijbregts Maj, 2003, Environ Sci Technol, V37, P2600, Doi 10.1021/Es020971+ Iso, 2006, 140402006 Iso, V2006 Iso, 2006, 14044 Iso, V2006 Iyer-Raniga U, 2012, Build Environ, V47, P138, Doi 10.1016/J.Buildenv.2011.08.001 Khasreen Mohamad Monkiz, 2009, Sustainability, V1, Doi 10.3390/Su1030674 Kofoworola Of, 2009, Energ Buildings, V41, P1076, Doi 10.1016/J.Enbuild.2009.06.002 Lopez-Mesa B, 2009, Build Environ, V44, P699, Doi 10.1016/J.Buildenv.2008.05.017 Mithraratne N, 2004, Build Environ, V39, P483, Doi 10.1016/J.Buildenv.2003.09.008 Monahan J, 2011, Energ Buildings, V43, P179, Doi 10.1016/J.Enbuild.2010.09.005 Ochsendorf J, 2011, Methods Impacts Oppo Ortiz O, 2009, Constr Build Mater, V23, P28, Doi 10.1016/J.Conbuildmat.2007.11.012 Ortiz-Rodriguez O, 2010, Sci Total Environ, V408, P2435, Doi 10.1016/J.Scitotenv.2010.02.021 Ove Arup And Partners Hong Kong Ltd, 2007, Intr Lif Cycl En Ass Peuportier Blp, 2001, Energ Buildings, V33, P443, Doi 10.1016/S0378-7788(00)00101-8 Rebitzer G, 2004, Environ Int, V30, P701, Doi 10.1016/J.Envint.2003.11.005 Rossi B, 2012, Build Environ, V51, P395, Doi 10.1016/J.Buildenv.2011.11.017 Sartori I, 2007, Energ Buildings, V39, P249, Doi 10.1016/J.Enbuild.2006.07.001 Scheuer C, 2003, Energ Buildings, V35, P1049, Doi 10.1016/S0378-7788(03)00066-5 Singh A, 2010, J Monetary Econ, V57, P729, Doi 10.1016/J.Jmoneco.2010.05.012 Suh S, 2007, Int J Life Cycle Ass, V12, P351, Doi 10.1065/Lca2007.08.358 Thiers S, 2012, Build Environ, V51, P276, Doi 10.1016/J.Buildenv.2011.11.018 Thormark C, 2002, Build Environ, V37, P429, Doi 10.1016/S0360-1323(01)00033-6 Utama A, 2008, Energ Buildings, V40, P1911, Doi 10.1016/J.Enbuild.2008.04.017 Utama A, 2009, Energ Buildings, V41, P1263, Doi 10.1016/J.Enbuild.2009.07.025 Van Ooteghem K, 2012, Build Environ, V49, P212, Doi 10.1016/J.Buildenv.2011.09.028 Wu Jg, 2010, Environ Manage, V46, P610, Doi 10.1007/S00267-010-9497-Z Abd Rashid, Ahmad Faiz Yusoff, Sumiani 0 Pergamon-Elsevier Science Ltd Oxford Renew Sust Energ Rev
Faculty of Engineering University of Malaya
Thermal energy storage as sensible or latent heat is an efficient way to conserve the waste heat and excess energy available such as solar radiation. Storage of latent heat using organic phase change materials (PCMs) offers greater energy storage density over a marginal melting and freezing temperature difference in comparison to inorganic materials. These favorable characteristics of organic PCMs make them suitable in a wide range of applications. These materials and their eutectic mixtures have been successfully tested and implemented in many domestic and commercial applications such as, building, electronic devices, refrigeration and air-conditioning, solar air/water heating, textiles, automobiles, food, …
Fatigue Of Swollen Elastomers
Faculty of Engineering University of Malaya
The compatibility of the properties of elastomer with conventional diesel fuel has made it favourable in many engineering applications. However, due to global energy insecurity issues, there is an urgent need to find alternative renewable sources of energy as replacements to conventional diesel. In this respect, biodiesel appears to be a promising candidate. Hence, research into the compatibility and fatigue characteristics of elastomers exposed to biodiesel becomes essential. The present paper introduces the first attempt to investigate the effect of different solvents on the fatigue of swollen elastomers. The filled nitrile rubbers are immersed in the palm biodiesel and conventional …
Evaluation Of The Mechanical Properties Of Aa 6063 Processed By Severe Plastic Deformation
Evaluation Of The Mechanical Properties Of Aa 6063 Processed By Severe Plastic Deformation
Faculty of Engineering University of Malaya
In this study, the mechanical properties, including surface hardness, tensile strength, fatigue, and fretting fatigue behavior of AA 6063 processed by equal channel angular pressing as the most efficient severe shear plastic deformation (SPD) technique, were investigated. Following the SPD process, samples were subjected to heat treatment (HT), hard anodizing (HA), and a combination of HT and HA. Rotating-bending fretting fatigue tests were performed to explore the samples' response to the fretting condition. From the experimental fatigue and fretting fatigue tests, it was apparent that the SPD treatment had a positive effect on enhancing the fatigue and fretting fatigue lives …
The Tribological And Electrochemical Behavior Of Hvof-Sprayed Cr3c2-Nicr Ceramic Coating On Carbon Steel
Faculty of Engineering University of Malaya
High Velocity Oxygen Fuel (HVOF) is an excellent approach to prepare a good, wear-resistant lamella of Chromium Carbide-Nickel Chrome (Cr3C2-NiCr) on carbon steel for high temperature application. This research investigates the effect of a thin, deposited layer of Cr3C2-NiCr on carbon steel in terms of wear and corrosion properties. The microstructure of the HVOF-sprayed Cr3C2-NiCr coating was characterized at each step by scanning electron microscopy. Wear testing was performed with a pin-on-disk tester. Wear weight loss was examined by applying different loads over a 9048.96 m sliding distance. Experimental results show that the wear resistance of the coated sample reduced …
Thermal Characteristic Reliability Of Fatty Acid Binary Mixtures As Phase Change Materials (Pcms) For Thermal Energy Storage Applications
Faculty of Engineering University of Malaya
The thermal characteristic reliability of two binary mixtures of fatty acid, myristic acid/palmitic acid/ sodium myristate (MA/PA/SM) and myristic acid/palmitic acid/sodium palmitate (MA/PA/SP), were investigated using a thermal cycling test setup for 0, 1000, 2000, 3000, and 3600 heating/cooling cycles. The changes in thermal properties and chemical bonding of both eutectic PCMs were measured using Differential Scanning Calorimetric (DSC) and Fourier Transform Infrared Spectroscopy (FT-IR) analyzer, respectively. MA/PA/SM and MA/PA/SP eutectic mixtures shows only minor changes in phase transition temperature (Tin, Ts) and in latent heat of fusion (ilk). Moreover, the chemical bonding structures of these eutectic PCMs show no …
Evaluation Techniques And Improvements Of Adhesion Strength For Tin Coating In Tool Applications: A Review
Faculty of Engineering University of Malaya
The adhesion between coating-substrate systems is an important factor in determining the performance and durability of coated engineering components. This paper reviews the microstructures and adhesion strength of titanium nitride (TiN) coating produced using two different processing methods: chemical vapor deposition and physical vapor deposition. Three methods to evaluate the adhesion strength of the coatings, namely the indentation test, laser spallation technique, and scratch test are presented and discussed in terms of their working principles, their advantages and disadvantages. The extrinsic and intrinsic factors influencing the adhesion strength of coating-substrate system, particularly for TiN coating, are also elaborated. The mechanisms …
Effect Of N-Butanol And Diethyl Ether As Oxygenated Additives On Combustion-Emission-Performance Characteristics Of A Multiple Cylinder Diesel Engine Fuelled With Diesel-Jatropha Biodiesel Blend
Faculty of Engineering University of Malaya
Jatropha biodiesel is considered as one of the most prospective renewable energy sources of Malaysia in recent years. Hence, an investigation was conducted for the improvement of jatropha biodiesel-diesel blend with the addition of 5-10% n-butanol and diethyl ether by vol. which are commonly known as oxygenated cold starting additive. Engine tests were conducted at variable speed, ranging from 1000 rpm to 3000 rpm at constant 80 N m torque on a 4-cylinder turbocharged indirect injection diesel engine. Engine performance parameters like brake specific fuel consumption, brake specific energy consumption, brake thermal efficiency and engine emissions like carbon monoxide, unburned …
A Combination Of Computational Fluid Dynamics (Cfd) And Adaptive Neuro-Fuzzy System (Anfis) For Prediction Of The Bubble Column Hydrodynamics
Faculty of Engineering University of Malaya
This paper shows a combination of computational fluid dynamics (CFD) and adaptive neuro-fuzzy inference system (ANFIS) to propose a new viewpoint for multiphase flow modeling, including the accuracy of soft computing techniques in the prediction of a three dimensional (3D) bubble column reactor. Since there are some difficulties (i.e., high computational time in numerical methods and expensive equipment in experimental techniques) in predicting bubble column reactors, particularly at different column locations and various operation conditions, soft computing methods can be developed as a favorable replacement for conventional measurement and prediction techniques. This study employs CFD beside the ANFIS method to …
Multiple-Objective Optimization In Precision Laser Cutting Of Different Thermoplastics
Multiple-Objective Optimization In Precision Laser Cutting Of Different Thermoplastics
Faculty of Engineering University of Malaya
Thermoplastics are increasingly being used in biomedical, automotive and electronics industries due to their excellent physical and chemical properties. Due to the localized and non-contact process, use of lasers for cutting could result in precise cut with small heat-affected zone (HAZ). Precision laser cutting involving various materials is important in high-volume manufacturing processes to minimize operational cost, error reduction and improve product quality. This study uses grey relational analysis to determine a single optimized set of cutting parameters for three different thermoplastics. The set of the optimized processing parameters is determined based on the highest relational grade and was found …
Characterization Of Nickel-Doped Biphasic Calcium Phosphate/Graphene Nanoplatelet Composites For Biomedical Application
Faculty of Engineering University of Malaya
The effect of the addition of an ionic dopant to calcium phosphates for biomedical applications requires specific research due to the essential roles played in such processes. In the present study, the mechanical and biological properties of Ni-doped hydroxyapatite (HA) and Ni-doped HA mixed with graphene nanoplatelets (GNPs) were evaluated. Ni (3 wt.% and 6 wt.%)-doped HA was synthesized using a continuous precipitation method and calcined at 900 degrees C for 1 h. The GNP (0.5-2 wt.%)-reinforced 6% Ni-doped HA (Ni6) composite was prepared using rotary ball milling for 15 h. The sintering process was performed using hot isostatic pressing …
Development Of A Control System For Artificially Rehabilitated Limbs: A Review
Development Of A Control System For Artificially Rehabilitated Limbs: A Review
Faculty of Engineering University of Malaya
Development of an advanced control system for prostheses (artificial limbs) is necessary to provide functionality, effectiveness, and preferably the feeling of a sound living limb. The development of the control system has introduced varieties of control strategies depending on the application. This paper reviews some control systems used for prosthetics, orthotics, and exoskeletons. The advantages and limitations of different control systems for particular applications have been discussed and presented in a comparative manner to help in deciding the appropriate method for pertinent application. Link to Full-Text Articles : http://link.springer.com/article/10.1007/s00422-014-0635-1
Eggshells: A Novel Bio-Filler For Intumescent Flame-Retardant Coatings
Eggshells: A Novel Bio-Filler For Intumescent Flame-Retardant Coatings
Faculty of Engineering University of Malaya
The aim of this study was to develop intumescent flame-retardant coatings that incorporate chicken eggshell (CES) waste as a novel eco-friendly bio-filler. Three flame-retardant additives, namely, ammonium polyphosphate phase II, pentaerythritol and melamine were mixed with flame-retardant fillers and acrylic binder to synthesize the intumescent coatings. The fire performance of the coatings was evaluated in accordance with 'BS 476: Part 6-Fire Propagation' and 'BS 476: Part 7-Surface Spread of Flame' test standards. It was found that 4 out of 5 of the coated specimens (B, C, D and E) neither showed surface spread of flame nor any afterglow combustion upon …
Effects Of Engine Variables And Heat Transfer On The Performance Of Biodiesel Fueled Ic Engines
Effects Of Engine Variables And Heat Transfer On The Performance Of Biodiesel Fueled Ic Engines
Faculty of Engineering University of Malaya
These days internal combustion engines are the major source of transportation. They run mainly on fossil fuels which are depleting day by day not only that they cause pollution which endangers human life and creates environmental problems. Of late biodiesel has emerged as a better alternative fuel for internal combustion engines due to its comparable properties with that of fossil fuels. Today's automobiles require economy of operation, high power output and last but not the least, reduction in greenhouse gases emitted by the vehicles. Such specific demands have compelled the researchers not only to focus on the parameters affecting the …
Growth And Characterization Of The Oxide Scales And Core/Shell Nanowires On Ti-6al-4 V Particles During Thermal Oxidation
Faculty of Engineering University of Malaya
Nanowires were grown on as-received and milled particles of Ti-6Al-4 V (Ti64) alloy under an optimum condition of 750 degrees C in an Ar atmosphere containing 15 ppm of oxygen. The as-grown nanowires and the underneath oxide scales developed on Ti64 particles were characterized by X-ray diffiactometry (XRD), field emission scanning electron microscopy (FESEM), scanning electron microscopy (SEM), transmission electron microscopy (TEM), scanning transmission electron microscopy (STEM) equipped with energy dispersive X-ray spectroscope (EDS). Results revealed the formation of oxide scales consisting of double layers on the surface of Ti64 particles. The outer oxide scale was a mixture of Al2O3 …
Tailoring Zno Nanostructures By Spray Pyrolysis And Thermal Annealing
Tailoring Zno Nanostructures By Spray Pyrolysis And Thermal Annealing
Faculty of Engineering University of Malaya
We report a novel synthesis of ZnO nanorods with hexagonal pyramid-like heads by a simple and low cost technique of spray pyrolysis with the help of zinc acetate and tin (IV) chloride pentahydrate precursors. In the present study, the growth of ZnO nanorods is optimized by varying a number of sprays and annealing temperatures in the synthesis process. FESEM analysis reveals that ZnO nanorods are observed when the number of sprays exceeds 150 and film-like structure is observed below 150 sprays. Nanorods are formed when the molar ratio of zinc acetate to tin (IV) chloride pentahydrate in the solution mixture …
Temperature Dependence Of Raman Scattering In 4h-Sic Films Under Different Growth Conditions
Temperature Dependence Of Raman Scattering In 4h-Sic Films Under Different Growth Conditions
Faculty of Engineering University of Malaya
The microRaman scattering of 4H-SiC films, fabricated by low pressure chemical vapor deposition under different growth conditions, is investigated at temperatures ranging from 80K to 550 K. The effects of growth conditions on E-2(TO), E-1(TO) and A(1)(LO) phonon mode frequencies are negligible. The temperature dependences of phonon linewidth and lifetime of E2(TO) modes are analyzed in terms of an anharmonic damping effect induced by thermal and growth conditions. The results show that the lifetime of E-2(TO) mode increases when the quality of the sample improves. Unlike other phone modes, Raman shift of A(1) (longitudinal optical plasma coupling (LOPC)) mode does …
Influence Of Biodiesel Blending On Physicochemical Properties And Importance Of Mathematical Model For Predicting The Properties Of Biodiesel Blend
Faculty of Engineering University of Malaya
The growing demand for green world serves as one of the most significant challenges of modernization. Requirements like largest usage of energy for modern society as well as demand for friendly milieu create a deep concern in field of research. Biofuels are placed at the peak of the research arena for their underlying benefits as mentioned by multiple researches. Out of a number of vegetable oils, only a few are used commercially for biodiesel production. Due to various limitations of edible oil, non-edible oils are becoming a profitable choice. Till today, very little percentage of biodiesel is used successfully in …
Field Analysis Of Indoor Air Quality In High Rise And Low Rise Green Offices With Radiant Slab Cooling Systems In Malaysia
Faculty of Engineering University of Malaya
Even though the green building concept is fairly new in Malaysia, the development of this industry has been growing in recent years prior to the launch of Malaysia's own standard, namely the Green Building Index (GBI). One of the criteria assessed in the GBI is the energy efficiency, which takes about 21% of the overall assessment. Considering this, the passive design has been included in the green building concept to reduce the energy usage without compromising occupant thermal comfort. This study attempts to assess the passive design effectiveness in terms of indoor air quality in green office buildings in the …
An Experimental Investigation On A Single Tubular Sofc For Renewable Energy Based Cogeneration System
Faculty of Engineering University of Malaya
Having negative impacts on environment and the scarcity of resources of conventional fossil fuels, fuel cell technology draws more attention as an alternative for providing the electrical energy in parallel with thermal energy. In this study, a single tubular solid oxide fuel cell (SOFC) with an electrolyte of Yttria-Stabilized Zirconia 8 mol% ceramic powder was experimentally investigated. The investigation illustrated the effects of three different fuel flow-rates (175 ml/min, 250 ml/min and 325 ml/min) and two operating temperatures (650 degrees C and 750 degrees C) on the output electrical and thermal powers. The highest electrical voltage (open circuit) and overall …
Development Of Optimum Process Parameters And A Study Of The Effects Of Surface Roughness On Brazing Of Copper
Faculty of Engineering University of Malaya
Brazing experiments on commercially-pure copper plates, using brazing filler metal (MBF-2005), are conducted at temperatures in the range of 650-750 degrees C for time-durations in the range of 5-15 min. Shear tests for braze-joints involved use of a universal testing machine. Based on the shear-test results, a new brazing cycle has been developed that corresponds to the greatest shear strength of the braze-joint. The brazing cycle has been performed under a controlled dry-argon atmosphere in a tube furnace. Microscopic observations were made by use of both optical and electron microscopes; whereas surface roughness measurements were made by using a TRIO …
A Novel Combined Severe Plastic Deformation Method For Producing Thin-Walled Ultrafine Grained Cylindrical Tubes
Faculty of Engineering University of Malaya
A novel severe plastic deformation (SPD) process entitled combined parallel tubular channel angular pressing (PTCAP) and tube backward extrusion (TBE) is proposed for producing thin-walled ultrafine-grained (UFG) tubes. In this new combined SPD approach, the PTCAP and TBE processes are consequently applied to the tube material in which a severe plastic strain is applied to produce a UFG thin-walled tube. This technique was performed on an AZ31 magnesium tube, and a remarkable grain refinement was achieved. The results showed that this method could easily produce a high strength thin walled tube. The microhardness increased significantly to 70 HV after the …
Continuous Dynamic Modelling Of Bimorph Piezoelectric Cantilevered Actuators Considering Hysteresis Effect And Dynamic Behaviour Analysis
Faculty of Engineering University of Malaya
Bimorph Piezoelectric Cantilevered (BPC) actuators have been of increasing interest in micro-manipulation processes during recent years. Due to properties such as transverse vibration, the performance and manoeuvrability have considerably improved, compared with conventional longitudinal piezoelectric actuators. Therefore, dynamic modelling of such actuators has been the centre of attraction. For this purpose, a target point on the actuator, e.g. the cantilever end tip, is usually considered as the actuator output. One degree of freedom lumped and continuous type dynamic models have been considered in prior research works. These types of modelling lead to two significant issues. First, the effect of higher …
Effects Of Carbon Black And The Presence Of Static Mechanical Strain On The Swelling Of Elastomers In Solvent
Faculty of Engineering University of Malaya
The effect of carbon black on the mechanical properties of elastomers is of great interest, because the filler is one of principal ingredients for the manufacturing of rubber products. While fillers can be used to enhance the properties of elastomers, including stress-free swelling resistance in solvent, it is widely known that the introduction of fillers yields significant inelastic responses of elastomers under cyclic mechanical loading, such as stress-softening, hysteresis and permanent set. When a filled elastomer is under mechanical deformation, the filler acts as a strain amplifier in the rubber matrix. Since the matrix local strain has a profound effect …