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Mechanical Engineering

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Faculty of Engineering University of Malaya

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Experimental And Numerical Investigation Of Heat Transfer In Cnt Nanofluids May 2015

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 …


Eggshells: A Novel Bio-Filler For Intumescent Flame-Retardant Coatings Apr 2015

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 …


An Experimental Investigation On A Single Tubular Sofc For Renewable Energy Based Cogeneration System Apr 2015

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 …


Effect Of Alcohol-Gasoline Blends Optimization On Fuel Properties, Performance And Emissions Of A Si Engine Jan 2015

Effect Of Alcohol-Gasoline Blends Optimization On Fuel Properties, Performance And Emissions Of A Si Engine

Faculty of Engineering University of Malaya

This study, as an observation, put its utmost effort to emphasize on the development of various physicochemical properties using multiple alcohols (C-2 to C-6) at different ratios compared to that of the conventional ethanol gasoline blend. To optimize the properties of multiple alcohol-gasoline blends, properties of each fuel were measured first. An optimization tool of Microsoft Excel "Solver" was used for obtaining the optimum blend. Using optimizing tool, three optimum blend ratios were selected which possessed maximum heating value (MaxH), maximum research octane number (MaxR) and maximum petroleum displacement (MaxD). These blends were used for testing in a four cylinder …


Review Of Improvements In Wire Electrode Properties For Longer Working Time And Utilization In Wire Edm Machining Jan 2015

Review Of Improvements In Wire Electrode Properties For Longer Working Time And Utilization In Wire Edm Machining

Faculty of Engineering University of Malaya

Wire electrical discharge machining (WEDM) is an important technology, which demands high-speed cutting and high-precision machining to realize productivity and improved accuracy for manufacturing hard materials. WEDM has experienced explosive growth and complexity of equipment as well as rising demand for the basic process tool (the wire electrode). Greater taper angles, thicker workpieces, automatic wire threading, and long periods of unattended operation make the selection of the ideal wire a much more critical basis for achieving successful operation. This paper focuses on the evolution of EDM wire electrode technologies from using copper to the widely employed brass wire electrodes and …