bluuebunny/crossref_metadata_2025 huggingface dataset:
Mechanical Properties and Environmental Stress Cracking Resistance of Rubber Toughened Polyester/Clay Composite
Authors: Noor Najmi Bonnia , Ahmad Sahrim Haji , Siti Norasmah Surip , Nurul S.S. , Hassan Noor Azlina , Anuar Hazleen
Published: October 2012

Crosslinked polyester clay nanocomposites were prepared by dispersing originically modified montmorillonite in prepromoted polyester resin and subsequently crosslinked using methyl ethyl ketone peroxide catalyst at different clay concentration. Cure process and the mechanical properties of rubber toughened polyester clay composite have been studied. Rubber toughened thermoset polyester composite were prepared by adding 3 per hundred rubber (phr) of liquid natural rubber (LNR) was used in the mixing of producing this composite. Modification of polyester matrix was done due to the brittle problem of polyester composite. Addition of LNR will increase the toughness of composite and produce ductile polyester. Two types of composites were produced which is clay-lnr polyester composite and clay polyester composite. Addition of liquid natural rubber significantly increased the impact strength and flexural properties. Result shows that addition of 6% of clay-lnr composite give good properties on impact, strength and flexural. From the ESCR test, both composites showed good resistance to environmental.
Influence of Magnetic Field on Reduction Chatter and of Surface Roughness in End Milling of Titanium Alloy - Ti-6Al-4V
Authors: Sulaiman Syidatul Akma , Amin A.K.M. Nurul , Arif M.D.
Published: October 2012

One of the most challenging issues in machining process is understanding the chatter phenomenon. Chatter mechanics is still not fully understood. It is inconsistent in character, making it difficult to analyze and predict. This research work investigates the influence of permanent magnets on chatter suppression in end milling of Titanium alloy (Ti-6Al-4V) using uncoated WC-Co insert. The experiments were designed based on the Response Surface Methodology (RSM) approach using DESIGN EXPERT (DOE) software. The experiments were performed under two different conditions: under normal condition and under the application of magnetic fields from two permanent magnets located in opposite direction. Ti-6Al-4V was used as the work material. The resultant average surface roughness was found to be reduced by a maximum of 50% due to magnet application. Scanning Electron Microscope (SEM) was used to analyze the chip morphology. The microphotographs showed the evidence of more stable chip formation under the influence of magnetic fields.
Effect of Melt-Blending Conditions on the Properties of HDPE/NR-Blends/Organoclay Nanocomposites
Authors: Zawawi Engku Zaharah Engku , Ahmad Sahrim H. , Rasid Rozaidi
Published: October 2012

The nanocomposites were prepared using melt intercalation technique in an internal mixer. Particular attention was given to investigate the influence of different processing condition such as rotor speed and mixing time on the tensile properties and also phase morphology of the nanocomposites using SEM. The nanocomposites were prepared from blend of high density polyethylene (HDPE), natural rubber (NR) and organoclay. Significant improvement in tensile strength and modulus of composites were obtained with rotor speed at 80 rpm. While optimum mixing time used was 12 min. The morphology of the composites determined from the fracture surface of tensile specimen showed a large filler particle or agglomeration of organoclay in the blend at low rotor speed.
Synthesis of ZnO Complex Structures at Different Molar Ratio of Zn (NO3)2 and KOH by Precipitation Method
Authors: Zayana N.Y. , Rusop M.
Published: October 2012

ZnO as a semiconductor with wide direct band gap (3.37 eV) and high exciton binding energy of 60 meV. It has attracted in several applications such as solar cells, field emission, sensor, etc. In this study, different ZnO complex structures were prepared by precipitation method at different molar ratio. Zinc nitrate as zinc source, potassium hydroxide as precipitating agent and sodium dodecly sulphate as surfactant were used to synthesis the ZnO. The effect of different molar ratio on the morphology and size of final product have been investigated. The final products were characterized by X-ray diffraction (XRD) with Cu Kα radiation, field emission scanning electron microscopy (FESEM) with an attached energy dispersive x-ray spectroscopy (EDS) and photoluminescence spectrofluorophotometer (PL). From XRD patterns, all synthesized ZnO shows good crystallinity. Different morphologies of synthesized ZnO were obtained from FESEM including flower composed flakes, flower composed radial rods and single straight rods while the EDS result demonstrates elements Zn and O obtained in the product. A very strong UV emission at ~390 nm observed in PL spectra indicated that the ZnO are of high crystal quality.
Morphological Study of Superabsorbent Polymer Hydrogels from Sago Starch
Authors: Nurizan O. , Zuraida Ahmad , Norhuda Hidayah Nordin
Published: October 2012

This paper comprises of the characterizations of superabsorbent polymer hydrogels based on sago starch (SS) prepared via graft copolymerization method with acrylic acid (AA) in the presence of ammonium persulphate (APS) and N, N-metylenebisacrylamide. The morphology of sago-g-acrylic (SAG) was evidenced by scanning electron microscope (SEM) images. The remarkable feature of this SAG is the porosity distribution with different amount of crosslinker. Less amount of crosslinker leads to increment in porosity distribution as well as water absorbency. This SAG with excellent water absorbency properties, being biodegradable in nature could be useful in sanitary products, horticulture and agriculture.
Synthesis of Carbon Nanotubes Using Zinc Nitrate as a Catalyst by Aerosol-Assisted Catalytic Single Furnace CVD
Authors: Maryam Mohammad , Suriani A.B. , Zobir S.A.M. , Rusop Mahmood Mohamad
Published: October 2012

Carbon nanotubes were synthesized from the aerosol-assisted catalytic CVD method using palm oil as the precursor and 0.05M zinc nitrate solution as the catalyst. The deposition temperature of the single furnace aerosol-assisted catalytic CVD ranged from 750 to 950 oC. The samples were then characterized using field emission scanning electron microscope (FESEM), Raman spectroscopy and thermogravimetric analysis (TGA). CNTs with different diameters and distribution were produced at certain deposition temperature and amorphous carbons were also present in the samples.
Unconventional Method for Monitoring of Waste Cooking Oil Transesterification
Authors: Adeyemi Nabeel A. , Mohiuddin A.K.M. , Mirghani Mohamed Elwathig Saeed , Jameel Ahmad Tariq
Published: October 2012

A technique to monitor transesterification of waste cooking oil (WCO) is presented. The technique was developed based on analogue signal from WCO, fatty acid methyl ester (FAME) and commercial palm oil (CPO). A low-pass filter design for the photodiode was used to obtain the characteristic analog signal generated by these oil samples and the signal was correlated to absorbance spectra of the oils using data from Fourier transform infrared (FTIR) equipment. A match was made between the analogue signals of the oil samples and calibrated against the FTIR spectra at 95% confidence level. Depletion of WCO during transesterification in a batch reactor correlated with the time observed for peak yield during biodiesel production. The results of the technique are discussed as a possible way to monitor transesterification process in a batch reactor.
Development of High Strength Ductile Iron with Niobium Addition
Authors: Alias Siti Khadijah , Abdullah Bulan , Jaffar Ahmed , Abdullah Abdul Hakim , Jenal Norhisyam
Published: October 2012

The studies emphasis on the development of niobium alloyed ductile iron with higher strength comparing to unalloyed ductile iron. 0.5wt% to 2wt% niobium were added into mixture of ductile iron casting containing pig iron, carburizer and steel scrap, and nodulized through 1.6wt% Fe-Si-Mg addition in CO2 sand casting process. Samples were then machined according to TS EN 10001 standards for tensile test and ASTM E23 for Charpy impact test. In addition, Rockwell hardness test was also performed. Microstructure observations were made after 2% Nital chemical etched and the phase structures were validated through XRD analysis. It was found that addition of niobium in ductile iron provide significant enhancement in mechanical properties when compared to unalloyed ductile iron. Addition of higher amount of niobium had further increased the strength and impact toughness properties. The enhancement of the mechanical properties is expected to further expand the applications of ductile iron.
Zn/MCM-41/MnO2 Leclanché Button Cell R2025 for Low Rate Applications
Authors: Mohd Zawi Nor Liza , Othman Raihan , Ani Mohd Hanafi
Published: October 2012

The present work reports the performance characteristics of Zn/MnO2 Leclanché cell employing an inorganic MCM-41 membrane separator. MCM-41 material comprises of one-dimensional, hexagonally ordered silicates mesostructure. The main advantage of MCM-41 membrane is its 3-in-1 functional features, viz. as ionic exchange channels, insulating layer between electrodes and electrolyte reservoir. Zn/MnO2 cell is constructed approximately to the size of R2025 coin cell. As the fabrication technique of MCM-41 membrane is merely by dip-coating process, it offers two advantages. First, the membrane could be prepared sufficiently thin and thus minimizing the internal losses of the cell. Second, it enables the construction of bipolar cell configuration with ease. Consequently, the results obtained demonstrate the volumetric energy density of Zn/MCM-41/MnO2 R2025 button cell has been extended by almost fivefold from 5.6 Wh/l to 26 Wh/l as bipolar cell configuration is utilized.
Effect of Sn Addition on Mechanical Properties of Zinc-Based Alloy
Authors: Azizan Farihan M. , Purwanto Hadi , Mustafa Mohd Yusry
Published: October 2012

Zinc-based alloy is developed as an alternative alloy for giftware material. However, zinc alloy has limitation such as its mechanical properties. Therefore, modifying the properties of zinc based alloy is needed to use it for giftware material. The effect of adding Sn on the mechanical properties and fractography of Zn alloys are investigated. The results indicate that adding 15 wt. % of Sn has significant effect on the improving of tensile strength and elongation of the zinc based alloy due to the formation of AgSn phase. The fracture surface of the tensile test specimen showed a mixed mode of fracture exhibiting ductile failure and brittle failure. Alloy with Sn content up to 15 % tends to have more ductile failure then the brittle one. The alloys of Zn-0.50Ag-15Sn have very good tensile strength and elongation, which are better than Zn-0.50Ag-1Sn and Zn-0.50Ag-7Sn alloys.
Effect of Holding Time on the Corrosion Potential of SS304
Authors: Purwanto Hadi , Manshor Hanisah
Published: October 2012

Stainless steels suffer from classical sensitization when encounter at certain temperature which results in precipitation of chromium carbide along grain boundary with simultaneous depletion of chromium from near grain boundaries. This study focused on corrosion potential test at different sensitization condition. The degree of chromium carbide precipitation was measured based on thickness of grain boundary. With increasing holding time, the thickness of the chromium depletion zone also increases due to diffusion of chromium into solid solution. Corrosion potential test showed that the heated sample at 700°C for 60 minutes resulted in highest corrosion current density and shifted its corrosion potential to more active potential. The potential tend to increase with increasing the degree of chromium carbide precipitation.
Effect of Coupling Agent on Mechanical Properties of Composite from Microcrystalline Cellulose and Recycled Polypropylene
Authors: Awanis J. , Anis Sofia S. , Samat Noorasikin
Published: October 2012

This study shows the effect of using 3-aminopropyltriethoxysilane (APS) and maleic anhydride-grafted polypropylene (MAPP) as coupling agent on composite of RPP/MCC fiber. The compositions of MCC were varied from 0, 2, 4, 8 and 12 wt%. The compounded samples were prepared into test specimens by using injection moulding. The RPP/MCC composites with and without the coupling agent were characterized through mechanical testing of flexural and impact test. The incorporation of the modified MCC was found to increase the modulus and flexural strength. The flexural test indicates that the addition of 4 wt% MCC-APS and 8 wt% MCC-MAPP significantly increased the flexural strength of the RPP composite compared to the unmodified MCC. The impact test shows higher impact strength at 4 wt% of RPP/MCC-APS and 2 wt% of RPP/MCC-MAPP, respectively.
Physical and Mechanical Properties of Thermoplastic Natural Rubber (TPNR) Nanocomposites
Authors: Hassan Noor Azlina , Norita Hassan , Ahmad Sahrim Haji , Rasid Rozaidi , Anuar Hazleen , Noor Najmi Bonnia , Siti Norasmah Surip
Published: October 2012

Thermoplastic natural rubber (TPNR) nanocomposites were prepared by melt blending method with the optimum mixing parameters (140oC, 100 rpm, 12 min) using internal mixer (Haake 600 P). The aim of this work is to study the effects of organo-montmorillonite (OMMT) on the physical and mechanical properties of TPNR with and without coupling agent (maleic anhydride grafted polyethylene, MA-PE). Significant improvement in tensile strength and modulus of TPNR nanocomposites were obtained with the presence of MA-PE.
Characterization and Stability Monitoring of Maghemite Nanoparticle Suspensions
Authors: Nurdin Irwan , Iskandar Idris Yaacob , Johan M. Rafie , Ang Bee Chin
Published: October 2012

Maghemite nanoparticle suspensions were synthesized using a co-precipitation method and characterized by a variety of techniques including XRD, TEM, magnetic measurement, DLS, and zeta potential. The stability of the suspension was monitored by measuring the particle size distribution using DLS over a period of two months. The diffraction pattern from XRD measurement confirmed that the particles were maghemite with an average crystallite size of 9.4 nm. TEM observations and analyses showed that the geometry of maghemite nanoparticles were nearly spherical with a mean physical diameter of 9.9 nm. The maghemite nanoparticles showed superparamagnetic behavior with saturation magnetization value of 32.20 emu/g. The mean hydrodynamic diameter of the suspension remained unchanged after two months which indicated no formation of aggregation. The hydrodynamic diameters recorded were 45.1 nm and 48.4 nm, respectively. Additionally, lack of sedimentation indicated that the suspension was stable. The suspension’s zeta potential values were 41.5 mV and 40.4 mV for as synthesized and after two month of storage respectively.
Facile Processing of γ-Alumina for Potential Energy Storage
Authors: Misran H. , Zini F.A.M. , Salim Musdalilah Ahmad , Singh Ramesh
Published: October 2012

Mesoporous γ-alumina with relatively high surface area of ca. 590 m2/g and pore size of ca. 2.0 nm to ca. 9.7 nm were successfully processed using facile and cost-effective method in the presence of renewable, low-cost templates. Controlled addition of water during the processing of the materials was found to control the rapid hydrolysis rate of alumina precursors resulting in mesoporous formation. In addition, these materials porosity was made up from framework porosity as well as textural porosity given rise from the aggregations of γ-alumina nanoparticulates. Regardless of the materials specific surface area value, the competitive adsorption amount of energy gas in 68 % humidity environment increased as relative crystallinity of the materials increased.
One-Dimensional ZnO Nanostructures by Wet-Chemistry Technique for Dye Sensitized Solar Cell Application
Authors: Yuwono A.H. , Sofyan Nofrijon , Harjanto S. , Daneswara D. , Ferdiansyah A. , Dharma H. , Hammerstein O.
Published: October 2012

In the current work, ZnO nanoflowers have been synthesized via sol-gel technique using a mixture of zinc-nitratetetrahydrate, ammonia and polyethylene glycol (PEG). Variation in PEG concentration and ammonia evaporation delay time was performed and the resulting nanoflowers have been investigated using x-ray diffraction (XRD) and scanning electronmicroscope (SEM). To explore the potential of the resulting ZnO nanorods, a prototype of dye sensitized solar cell (DSSC) has been fabricated. For this purpose, the nanorods were grown directly on conducting ITO substrates by nanoseeding technique. With a variation in nano seeding time for 2, 4 and 6 days, followed by hydrothermal process at 80oC for 20 hours, ZnO nanorods with average diameter of 82, 332 and 1385 nm have been synthesized. The performance test showed the resulting open circuit voltage (Voc) was increased from 398 to 486 mV when the diameter of ZnO nanorods increased from 82 to 332 nm. However, the Voc decreased slightly to 456 mV when the nanorods further increased to 1385nm. The phenomenon is related to the interaction between the semiconductor oxide and the Ruthenium complex organic dye.
Prediction of Surface Roughness in Compressed Air Jet Assisted High Speed End Milling of Silicon Using Diamond Coated Tools
Authors: Amin A.K.M. Nurul , Mahmud M.A. , Arif M.D.
Published: October 2012

The majority of semiconductor devices are made up of silicon wafers. Manufacturing of high-quality silicon wafers includes numerous machining processes, including end milling. In order to end mill silicon to a nano-meteric surface finish, it is crucial to determine the effect of machining parameters, which influence the machining transition from brittle to ductile mode. Thus, this paper presents a novel experimental technique to study the effects of machining parameters in high speed end milling of silicon. The application of compressed air, in order to blow away the chips formed, is also investigated. The machining parameters’ ranges which facilitate the transition from brittle to ductile mode cutting as well as enable the attainment of high quality surface finish and integrity are identified. Mathematical model of the response parameter, the average surface roughness (Ra) is subsequently developed using RSM in terms of the machining parameters. The model was determined, by Analysis of Variance (ANOVA), to have a confidence level of 95%. The experimental results show that the developed mathematical model can effectively describe the performance indicators within the controlled limits of the factors that are being considered.
Thermal Stability of Nickel Molybdenum Electrodeposits
Authors: Suryanto Suryanto , Ani Mohd Hanafi
Published: October 2012

Thermal stability of nickel molybdenum electrodeposits was investigated. This investigation is important to show that electrodeposits can be used at elevated temperature and to understand electrodeposit behaviour as a function of temperature. Crack-free electrodeposits with up to 17 at% molybdenum were produced by the square pulse electro-deposition technique from a solution containing nickel sulphamate. The experiment was performed using vacuum furnace. Microstructure of deposits was investigated using microscope SEM, while the phase of deposits was studied using x-ray diffraction. Chemical composition of deposits was observed using energy dispersive x-ray analyzer and hardness of deposits was measured using micro hardness tester. The result shows that nickel molybdenum electrodeposits stable up to 400 oC. For 550 oC, grain growth was observed to start but the hardness of electrodeposits has no significant changed. Hardness analysis shows that hardness of electrodeposits does follow Hall Petch relationship.
Mechanical Performance and Water Absorption Resistance of HIPS/MWCNTs Nanocomposite
Authors: Al-Ghamdi Ahmed S. , Mohammad Yeakub Ali
Published: October 2012

The purpose of this research work is to evaluate the effects of reinforcing high impact polystyrene (HIPS’s) with multiwall carbon nanotubes (MWCNTs) on the mechanical performance and the water absorption resistance. The significant changes in HIPS/MWCNTs nanocomposite on the mechanical performance and water absorption resistance were investigated with different weight percentage of MWCNTs in the range of 0.10 wt% to 10 wt%.
Aluminium-Copper-SiCp Composite Materials Corrosion in Biodiesel
Authors: Maleque Md Abdul
Published: October 2012

The aim of this paper is to investigate the corrosion behaviour of aluminium-copper-SiCp composite materials under palm oil biodiesel (POB). Corrosion behaviour test was performed using both weight loss and polarization methods for two different types of aluminium-copper-SiCp composite materials such as ACM 1(2% Cu, 20% SiC, and 78% Al) and ACM 2 (6% Cu, 20% SiC, and 72% Al). The materials were characterized using scanning electron microscope (SEM) for surface morphology. The results showed that corrosion rate of ACM 2 is higher than ACM 1 in presence of palm oil biodiesel due to the higher amount of copper in the composite which is more susceptible to corrosion. The surface morphology after corrosion test showed that chemical corrosion occurs on the surface due to the dominant of the fatty acid in the POB. Therefore, in this study it can be concluded that aluminium-copper-SiCp composite materials are susceptible to corrosion in biodiesel.
Internal Oxidation of Ni-Cr-Al Alloys under Various Oxygen Partial Pressures at 1273 K
Authors: Ani Mohd Hanafi , Herman Sukreen Hana , Suryanto Suryanto , Othman Raihan
Published: October 2012

Alloys for high temperature application always rely on their ability to form protective, dense Cr2O3 and Al2O3 scales. In case of Ni-Cr binary alloy, a minimum composition of Cr is required for the formation of continuous protective scale. However, addition of small amount of third element such as Al may results in decrease of required Cr composition to form protective scale. This study aims to clarify the effect of ternary element on the formation of protective scale quantitatively. Ni-Cr alloys composed with 2 mass% and 4 mass% of Al were exposed in oxidizing environment under Cr/Cr2O3, Fe/FeO and Ni/NiO oxygen partial pressure. The oxidation of all samples is following parabolic rate’s law. XRD and SEM results show that Al2O3 and Cr2O3 are formed internally. Parabolic rate’s constant of samples oxidized in Ni/NiO oxygen partial pressure is higher by few magnitude orders. Higher Al concentration decreases the parabolic rate’s constant. It is concluded that the formation of protective scale is enhanced by the addition of Al as ternary element in Ni-Cr alloys.
Biodegradability Analysis of KBF Reinforced Poly(lactic Acid) Biocomposites
Authors: Othman Maizatulnisa , Nor Azowa Ibrahim , Ruzaidi C.M. , Mohd Nazarudin Zakaria , Halim Zahurin
Published: October 2012

Poly(lactic acid) (PLA) and kenaf bast fiber (KBF) were melt-blended using brabender into films in the PLA/KBF ratios of 100/0, 90/10, 70/30 and 50/50 for natural soil burial test. This formulation was used to study the biodegradability of PLA and PLA/KBF biocomposites. It was found that the decompositions of the biocomposite were faster than pure PLA. The SEM morphology of the tensile fracture surface of the 30% and 50% of PLA/KBF biocomposites presented larger pores and degradation areas than smaller KBF loading (10 wt%). This result shows that the addition of larger fibre loading to the PLA matrix increased the micropore surface area of the PLA/KBF biocomposite hence accelerated the decompositions time of the biocomposites.
Effect of NaVO3 Concentration on Corrosion Resistance of Conversion Coating on AZ91D Magnesium Alloy
Authors: Sidik N.F.W.M. , Zamzuri M.Z.M. , Mat Salleh M. , Ismail Khairul Azwan
Published: October 2012

Anticorrosive oxide films were successfully prepared on AZ91D magnesium alloy by chemical conversion coating in La (NO3)3 electrolytes with and without NaVO3. The morphologies and chemical composition were characterized by optical microscope, scanning electron microscope (SEM) and energy dispersive analysis (EDX). The corrosion resistances of the oxide films were evaluated by salt immersion test. The result showed that the oxide film formed in electrolyte with NaVO3 is successful in providing superior corrosion resistance for AZ91D magnesium alloy.
The Effects of Mo Addition on the Structure of Scales Formed in High Si Steel at 1150°C
Authors: Mohd Zainal Ahmad Zaki , Kurokawa Kazuya
Published: October 2012

High Si steels (base steel and with addition of 0.1, 0.3, 0.5mass% Mo) were oxidized in a N2-3%O2-20%H2O atmosphere at 1150oC for 0.3-10.8ks. The oxidation kinetics showed that base steel has the highest weight gain. In contrast, 0.5Mo has the lowest weight gain. From SEM results, the scale thickness decreased as Mo content increased. Distribution of alloying elements showed that Mo is enriched in internal oxidation zone (IOZ) and played a role in slowing the outward diffusion of Fe, thus, producing a thinner Fe oxide scale and lower weight gain.
Evaluation of Elastic Modulus and Hardness of Polylactic Acid-Based Biocomposite by Nano-Indentation
Authors: Lutpi H.A. , Anuar Hazleen , Samat Noorasikin , Surip Siti Norasmah , Bonnia Noor Najmi
Published: October 2012

This study focuses on the micromechanical properties of polylactic acid (PLA) reinforced with kenaf fiber (KF) and organo-montmorillonite (OMMT) hybrid biocomposite by using nanoindenter. Nanoindenter is an analytical device that can record small load and depth with high accuracy and precision which can be used to determine the modulus, hardness and other mechanical properties of nanomaterials. The result shows that the optimum properties of the hardness and elastic modulus were dominated by PLA-KF-OMMT hybrid composite.
The Crystallinity and Hardness Properties of Al-Cu/SiCp New Composite Materials
Authors: Arifutzzaman A. , Maleque Md Abdul , Sujan D.
Published: October 2012

The main aim of this paper is to investigate the crystallinity and hardness properties of Al-Cu/SiCp matrix composite (AMC) materials. The materials were prepared using a noble stir casting technique by varying the percentage of Cu in the Al-Cu matrix. Qualitative X-ray analysis has been carried out to characterize the crystallinity of the Al-Cu/SiCp as-cast composite materials. Sample was cut and shaped into 25 mm×15 mm×4 mm in dimension then polished with diamond paste. X-ray diffraction diagrams were recorded using a transmission technique with a SHIMADZU Lab X (XRD-6000) X-ray generator operating at Cu Kα1 radiation. Hardness test was conducted using Vickers hardness tester (Mitutuyo, MVK-H2). The results indicated that a significant crystal growth was occurred in the composite materials due to increase of Cu from 2 to 4 % whereas a slight improvement of crystallinity was observed when the Cu percentage was increased from 4 to 6 % in the matrix. It was also revealed from the result that a similar trend was grasped in hardness increment with the crystallinity of Al-Cu/SiCp AMCs.
Improving Structural and Micro-Raman Properties of Camphor-Grown Pristine Carbon Nanotubes with Special Focus on Single-Stage Thermal Annealing System
Authors: Shamsudin M.S. , Lahori I.A. , Abu Bakar Suriani , Abdullah Saifollah , Yahya S.Y.S. , Rusop Mahmood Mohamad
Published: October 2012

The camphor-grown pristine carbon nanotubes (CNT) was annealed by a single-stage thermal annealing system through controlled ambient in air, argon and nitrogen, are reported. Field emission scanning electron microscopy images confirmed that the heat treatment process gives a place to re-ordering carbon nanostructures which involves: (i) an elimination of structural defects and (ii) better graphitization of the amorphous carbon phase without damaging CNT structure. The room temperature micro-Raman measurements showed that no significant changes on the D and G-line position. However, different annealing gas ambient could give different values degree of graphitization (ID/IG ratio) due to the nature of gas itself. It reveals that single-stage thermal annealing system is relatively simple and effective to obtain an ideal CNT.
Microstructure-Hardness Relationship of Inconel 718 Compressor Blade Heat Treated at Different Conditions
Authors: Ismail F. , Mridha Shahjahan
Published: October 2012

The superalloy of Inconel 718 variety is widely used to produce compressor blade in gas turbine engine. The blade tip invariably wears in services and thus requires frequent metallization for repairing. In most commercial Turbine Engine Industries the metallised blades, after grinding, undergo a stress relieving heat treatment at 7600C before return for applications. In this study, the metallised blade is heat treated at different conditions and compared its microstructure and hardness with those of the standard stress relieving treatment blades used in most industries. The microstructure of the stress relieving sample contains dendrite with hardness of 230 HV for the melt zone, 190 HV for the Heat Affected Zone (HAZ) and 420 HV for the parent metal. Solutionising at 982 or 10660C developed hardness less than 220 HV in all sections. By long time ageing treatment of the solutionised sample developed high hardness across the whole blade. These treatments homogenized the microstructure and produced high hardness values by precipitation of secondary phase structures across the blade.
Optimization of Cutting Parameters for High Speed End Milling of Single Crystal Silicon by Diamond Coated Tools with Compressed Air Blowing Using RSM
Authors: Mahmud M.A. , Amin A.K.M. Nurul , Arif M.D.
Published: October 2012

This paper presents the thorough experimental analysis on high speed end milling of single crystal silicon using diamond coated tools. Experiments were conducted on CNC milling machine. The design of the experiments was based on the central composite design (CCD) technique of Design Expert software. Response Surface Methodology (RSM) was used to develop mathematical imperial model to establish a correlation between machining parameters (cutting speed, feed and depth of cut) and machined surface roughness in high speed end milling of single crystal silicon using 2mm diameter diamond coated tools. The optimum machining parameters were determined using the optimization tool of Design Expert software based on the desirability function. Finally, confirmation tests were performed to validate the developed model.
Composite Coating on Steel Surfaces by Adding TiC and h-BN Particulates under TIG Torch Melting
Authors: Mridha S. , Taib N.I. , Idriss A.N.
Published: October 2012

Wear is a common problem for engineering components subjected to dynamic loading. Surface modification is mostly applied to reduce the wear. An exploratory research is conducted to form a composite coating on AISI 4340 steel surfaces by incorporating a mixture of TiC and hexagonal Boron Nitride (h-BN) particulates using powder placement and TIG torch melting techniques. Initial results show the evidence of TiC incorporation in all tracks but the presence of h-BN is limited in a few tracks. However, processing conditions are identified that can produce composite coatings incorporating both TiC and h-BN particulates. The melt microstructure consists of a small amount of un-melted TiC and h-BN, partially melted TiC particulates with eutectic structure containing precipitated TiC and TiB2 particles. Hardness of the coating is found to fluctuate along the melt depth. However, the maximum hardness of the coating is about 3 times the base hardness of 250 HV.
Microstructure of TIG Melted Composite Coating on Steel Produced Using 1.0 and 1.5 mg/mm2 TiC at an Energy Input of 2640 J/mm
Authors: M. Idriss A.N. , Mridha S.
Published: October 2012

Surface modification by reinforcing ceramic particulates can give protection against wear and corrosion of metal. In this work, two different amounts of TiC powder of nominal size 45 to 100 µm were embedded on AISI 4340 steel surfaces by melting under a Tungsten Inert Gas (TIG) welding torch with an energy input of 2640 J/mm. The microstructure, geometry and hardness of the single track composite layers were investigated. The resolidified melt tracks were hemispherical in shape. With increasing TiC content, the melt dimensions reduced a little but the microstructure had a remarkable change. The track with 1.5 mg/mm2 TiC gave more un-melted TiC, partially melted TiC and agglomeration of ceramic particulates while the 1.0 mg/mm2 track dissolved most TiC particulates and precipitated carbides in the form of dendrite, globular and flower type particles; dendrites are almost absent in the 1.5 mg/mm2 track. A reduced TiC addition created more fluid melt which accelerated dissolution of TiC and that caused more carbide precipitation in the 1.0 mg/mm2 track compared to that with 1.5 mg/mm2 track. The 1.0 mg/mm2 track produced lower hardness of 1065 Hv compared to 1350 Hv for the 1.5 mg/mm2 track.
Flexural and Impact Properties of Kenaf-Glass Hybrid Composite
Authors: Maleque Md Abdul , Afdzaluddin Atiqah , Iqbal Mohammed
Published: October 2012

This paper investigates the flexural and impact properties of kenaf-glass (KG) fibers reinforced unsaturated polyester (UPE) hybrid composite on a source of green composite. The matrix is kept constant with 70 % volume fraction while kenaf and glass fibers were varied, such as 7.5/22.5 v/v, 15/15 v/v and 22.5/7.5 v/v. The 30 % kenaf and 30 % glass are also used for the preparation of composite materials. The kenaf fiber was treated with 6% sodium hydroxide (NaOH) diluted solution for 3 hours. Hybrid composites are fabricated using sheet molding compound (SMC) process. The mechanical tests, such as flexural and impact are performed using ASTM D790-03 and ASTM D256-04 respectively. The study showed that the highest flexural strength was obtained from treated kenaf with 15/15 v/v KG fiber reinforced hybrid composite while untreated of 15/15 v/v KG composite showed the highest value of impact strength in this investigation. This can be concluded that 15/15 v/v KG fiber reinforced unsaturated polyester hybrid composite is the most appropriate hybrid composite which can be considered for many engineering structural applications, such as automotive, aerospace, construction or sports.
Crystalline and Structural Properties Dependence on RF Power and Deposition Temperature of Sputtered Nanocrystalline Silicon Thin Films on Teflon and Glass Substrates
Authors: Mahzan Norhidayatul Hikmee , Hashim Shaiful Bakhtiar , Herman Sukreen Hana , Rusop M.
Published: October 2012

Nanocrystalline silicon (nc-Si) thin films were deposited on glass and polytetrafluoroethylene (PTFE, teflon) substrates using Radio frequency (RF) magnetron sputtering. The effect of RF power and deposition temperature on the physical and structural properties of nc-Si on the glass and Teflon substrate was studied. The thin films properties were examined by Raman spectroscopy and field emission scanning electron microscopy (FESEM). We found that the thickness of thin films increased with increased RF power and deposition temperature. Raman spectroscopy results it showed that, with increasing RF power and deposition temperature can cause the changing of crystallinity on both glass and Teflon substrate.
Properties of Sago Starch-Nanoclay Biocomposites Film
Authors: Nur Humairah A.R. , Zuraida Ahmad
Published: October 2012

This paper reported on properties of sago starch that was compounded with montmorillonite (MMT) nanoclay to form biodegradable composites film. The film was fabricated via film casting method with glycerol as a plasticizer. The investigated biocomposites film was prepared at starch-glycerol/MMT weight fraction of 90/10, 85/15, 80/20 and 75/25. The physical properties of the film, namely thickness and density were studied and results show that incorporation of nanoclay as filler affects the biocomposites physical properties. Scanning Electron Microscope (SEM) and Fourier Transform Infrared Spectroscopy (FTIR) were used to analyze the film’s morphological properties and chemical characteristics, respectively. SEM shows that less clay content in the film produces homogenous phase and well dispersed of clay platelets within the starch matrix. FTIR summarizes that MMT nanoclay is able to form hydrogen bonding with starch.
Effect of Bath Formulation and Plating Current Density on Electrodeposited Zinc Anode’s Capacity in Zinc-Air Cell
Authors: Othman Raihan , Ahmat Farouq , Ibrahim Muhd Amlie , Nor Hairin Assayidatul Laila , Ani Mohd Hanafi
Published: October 2012

Zinc anode is electrodeposited from a 2-M zinc chloride electrolytic bath with varying ammonium chloride supporting electrolyte concentrations (0-5 M) and plating current density (0.1 – 0.6 A cm-2). The total charge quantity supplied during electrodeposition is fixed at 150 mAh. Alkaline zinc-air cell is fabricated using the electrodeposited zinc anode and characterized according to its discharge capacity at constant load current of 20 mA. The effect of various qualities of zinc electrodeposits on the cell discharge performance is discussed. It is found that zinc electrodeposits prepared from electrolytic bath of 5-M ammonium chloride and 0.5 A cm-2 plating current density produced zinc-air cell with the highest output energy i.e. 24 mWh. We observe that the influence of plating current density is more prominent than the plating bath formulation on the zinc anode performance in the cell.
Influences of Grain Refining Conditions on Sensitization in 16 wt% Chromium Ferritic Stainless Steel Welds
Authors: Amuda M.O.H. , Mridha S.
Published: October 2012

The paper discusses sensitization characteristics in medium chromium Ferritic Stainless Steel (FSS) welds processed at two different grain refining conditions namely metal powder addition and cryogenic cooling. Tungsten Inert Gas (TIG) torch welded samples were exposed to 10% oxalic acid electrolytic etch for evaluation of sensitization. Empirical analysis indicated that, though both the grain refining conditions reduced the sensitization width relative to the conventional weld, the width was virtually nil with cryogenic cooling suggesting the elimination or reduction of sensitization. Similarly, the microstructure of cryogenically cooled welds showed no ditched grain boundary but aluminum powder treated welds revealed extensive ditching and none in titanium treated welds while knifeline attack was observed in welds treated with the mixture of aluminum and titanium powders.
Laser Cutting Characteristic on the Laminated Carbon Fiber Reinforced Plastics (CFRP) Composite of Aerospace Structure Panel
Authors: Wahab Md. Saidin , Rahim Erween Abdul , Rahman N.A. , Uyub M.F.
Published: October 2012

Carbon fiber reinforced plastic (CFRP) composites as high performance material in aerospace industry. The application of laser technology to cut the CFRP shows promising advantages. Therefore, several cutting parameters such as pulse energy, pulse repetition rate, cutting speed and pulse duration need to be taken into consideration. In this study, the effect of the aforementioned parameters on heat affected zone (HAZ), kerf width and taper angle were evaluated. The results showed that pulse energy and pulse repetition rate gave a significant effect on the cutting characteristic.
Optimization of Surface Roughness in End Milling of Titanium Alloy Ti-6Al-4V under the Influence of Magnetic Field from Permanents Magnets
Authors: Sulaiman Syidatul Akma , Amin A.K.M. Nurul , Arif M.D.
Published: October 2012

This paper presents the effect of cutting parameters on surface roughness in end milling of Titanium alloy Ti-6Al-4V under the influence of magnetic field from permanent magnets. Response Surface Methodology (RSM) with a small central composite design was used in developing the relationship between cutting speed, feed, and depth of cut, with surface roughness. In this experiment, three factors and five levels of central composite with 0.16817 alpha value was used as an approach to predict the surface roughness, in end milling of titanium alloy, with reasonable accuracy. The Design-Expert 6.0 software was applied to develop the surface roughness equation for the predictive model. The adequacy of the surface roughness model was validated to 95% by using ANOVA analysis. Finally, desirability function approach was used to determine the optimum possible surface roughness given the capabilities of the end machine.
Influence of Etching Time on Surface Structural Properties of p- and n- Type Porous Silicon Nanostructures by Photo-Electrochemical Anodic Etching
Authors: Asli N.A. , Zubaidah Maslihan Ain , Yusop S.F.M. , Ahmad Sekak Khairunnadim , Rusop Mohammad , Abdullah Saifolah
Published: October 2012

Porous silicon nanostructures (PSiN) are nanoporous materials which consist of uniform network of interconnected pore. The structure of PSiN is depending on etching parameters, including current density, HF electrolyte concentration, substrate doping type and level. In this work, the results of a structural p-type and n-type of porous silicon nanostructures were investigated by Field Emission Scanning Electron Microscopy (FESEM) and Atomic Force Microscopy (AFM) is reported. Samples were prepared by photo-electrochemical anodization of p- and n-type crystalline silicon in HF electrolyte at different etching time. The surface morphology of PSiN was studied by FESEM with same magnification shown n-type surface form crack faster than p-type of PSiN. While the topography and roughness of PSiN was characterize by AFM. From topography shown the different etching time for both type PSiN produce different porosity and roughness respectively. There is good agreement between p- and n-type have different in terms of surface characteristic.
I-V and Surface Topography Study of Nanostructure Porous Silicon Layer Prepared by Electrochemical Etching
Authors: Fadzilah Suhaimi Mohd Husairi , Zubaidah Maslihan Ain , Yusop Shamsul Faez M. , Mohamad Rusop Mahmood , Abdullah Saifolah
Published: October 2012

This article reports on the electrical properties of porous silicon nanostructures (PSiNs) in term of its surface topography. In this study, the PsiNs samples were prepared by using different current density during the electrochemical etching of p-type silicon wafer. PSiNs has been investigated its electrical properties and resistances for different surface topography of PSiNs via current-voltage (I-V) measurement system (Keithley 2400) while its physical structural properties was investigated by using atomic force microscopy (AFM-XE100).
Assessment on Copper C194 Mechanical Properties Variations in Typical Semiconductor Assembly Production Line
Authors: Amirul Abdullah Rashid , Nor Hayati Saad , Abdullah Bulan
Published: October 2012

Process variation is inevitable for any production line regardless of the industry. The trend for smaller, lighter yet multifunctional devices has created high expectation for the semiconductor manufacturer to produce more robust and highly reliable devices. One way to achieve this is by assessing the variance performance of the assembly production. In this study, the mechanical properties of copper alloy C194 used as the lead frame for particular IC device have been investigated. Samples from control and defect groups been subjected to hardness (Rockwell test) and tensile (Instron test) while the optical microscopy used to verify the microstructure. The result shows that the hardness and tensile of the defect group is relatively lower than the control group while the elongation of the defect group is almost 10% higher. This finding is very useful to be shared with the process owner so that in-depth investigation on the lead frame material consistency or the temperature range optimization can be carried out to prevent such variations that contribute to the inconsistence wire bond yield performance.
Influence of Energy Parameters of Micro WEDM on Kerf
Authors: Mohammad Yeakub Ali , Liew W.Y.H. , Gure S.A. , Asfana B.
Published: October 2012

This paper presents the estimation of kerf width in micro wire electrical discharge machining (micro WEDM) in terms of machining parameters of capacitance and gap voltage. An empirical model is developed by the analysis of variance (ANOVA) of experimental data. Using a wire electrode of 70 µm diameter, a minimum kerf width is found to be 92 µm for the micro WEDM parameters of 0.01 µF capacitance and 90.25 V gap voltage. Around 30% increament of the kerf is found to be high. The analysis also revealed that the capacitance is more influential parameter than gap voltage on kerf width produced by micro WEDM. As the gap voltage determines the breakdown distance and affects the wire vibration, the wire vibration factor is to be considered in the analysis and in formulation of model in future study.
High Speed Milling of Silicon Carbide with Diamond Coated End Mills
Authors: Konneh Mohamed , Iqbal Mohammad , Kasim M. Asnawi B. , Isa Nurbahiah B. Mohd
Published: October 2012

The primary applications of silicon carbide SiC-based materials, which include include micro-structures, optoelectronic devices, high temperature electronics, radiation hard electronics and high power/high frequency devices to name a few have necessitated the need for machining SiC. The paper presents the outcome of milling of silicon carbide using diamond coated end mill under different machining conditions in order to determine the surface roughness parameter after the machining processes. Relationship between the machining parameters and response variables has been established and a mathematical model has been predicted, the minimum roughness value, Rz being 0.19 µm.
Diamond Grit Size Prediction in Surface Grinding Silicon Carbide
Authors: Konneh Mohamed
Published: October 2012

High hardness, chemical stability, attractive high temperature wear resistance, low density and strength at elevated temperature are the advantages of ceramics over other materials. These properties have made a number of components made of hard and brittle materials, typically represented by advanced ceramics gained applications in industrial sectors over the past two decades. Nevertheless the benefits due to the salient features of ceramic materials go along with some difficulties with machining in general because of their high values of hardness and very low fracture toughness as compared to other metallic materials and alloys. This paper presents an experiemntal study on identifying the diamond grit size and grinding condition that produced low surface roughness value, Ra and less micro-fractures on ground silicon carbide work-piece material.
Optimization of Inconel 600 Alloy Micro Turning Process Using Grey Relational Analysis
Authors: Durairaj M. , Gowri S.
Published: October 2012

Micro turning is a process by which micro components can be produced. This paper deals with the CNC micro turning of Inconel 600 alloy with titanium nitride insert tool. Full factorial experiments were conducted to obtain tool Flank wear and Surface roughness (Ra) for different cutting conditions. Using the measured data, Grey Relational Analysis is used to predict the optimal parameter conditions for controlled tool flank wear and better surface finish.
Optimization of Wire Cut Electrical Discharge Machining of Inconel 800 Using Grey Relational Analysis
Authors: Durairaj M. , Gowri S. , Gauthamkumar M.H. , Kumar M. Ashok , Aishwarya R.
Published: October 2012

Wire Electrical Discharge Machining is one of the important non-traditional machining processes, which is used for machining difficult to machine materials and intricate profiles. In this present study, machining is done using Wire-Cut EDM and experimentation is planned according to Taguchi’s design of experiments [2]. Each experiment has been performed under different cutting conditions of gap voltage, pulse ON time, and pulse OFF time and Wire feed. Inconel 800 was selected as a work material and Brass wire of 0.25mm diameter as the tool to conduct the experiments. From experimental results, the surface roughness and Kerf Width was determined for each machining performance criteria. Grey Relational Analysis [1] is used for optimization of Surface Roughness and Kerf width.