Advanced Materials Research Vol. 795

Abstract: A characterization of microstructure and interface was made on the composites Al-4 % Cu reinforced with 15 wt. % glass particulate. The composite was fabricated by powder metallurgy followed by solution treatment and artificial ageing. The microstructures of the composite showed that the glass particulates were in-homogenously distributed in the matrix and segregated near copper. The aluminum oxide layer was found between aluminum, copper and glass particulate. Micro cracks were observed in the aluminum oxide layer and at the interface between aluminum oxide layer and aluminum. Hardness increased as ageing time increased. Interface behavior and aging time influenced the hardness of the composite.

Abstract: The effects of benzyl urea into RHDPE/NR/CFF composites with different fibers loading were studied. The composites were prepared using BrabenderPlasticorder at 160 °C with rotor speed of 50rpm. The composites were characterized in respect of their tensile properties and morphology. The results indicated that RHDPE/NR/CFF with benzyl urea composites show higher values of tensile strength, Youngs modulus, but lower elongation at break than RHDPE/NR/CFF composites. RHDPE/NR/CFF with benzyl urea composites gave a better interfacial adhesion between the matrix and the fiber than RHDPE/NR/CFF composites as evidence using SEM.

Abstract: Stress shielding interaction effect of two parallel edge cracks in finite body under uniaxial loading is analysed using developed finite element (FE) analysis program. In present study, the stress shielding interaction is formulated as a mathematical model called stress shielding damage (SSD) model. SSD model used to define the combination and re-characterization of crack interaction from multiple cracks to single crack. Focus is given to weak crack interaction state as the crack interval exceed the length of cracks (b > a). The crack interaction factors are evaluated based on Griffith strain energy release rate and mode I SIF using J-integral analysis. For validation, the stress shielding factor parameters are compared to single edge crack SIF as a state of zero interaction in a form of crack unification limit (CUL) and crack interaction limit (CIL).

Abstract: This project is focused to study on the cooling performance of liquid cooling system under different process parameter. In this research, a liquid cooling system with copper block that simulates CPU, was setup to identify cooling performance of distilled water and vegetable oil at different mass flow rates (distilled water: 8.00g/s, 10.60g/s & 13.24g/s; vegetable oil: 1.22g/s, 1.30g/s & 1.38g/s) and input power (29.12W & 47.66W). The cooling performance of each fluid was characterized by the properties of: heat transfer coefficient, thermal resistance and also, the maximum CPU temperature (T4 at 66min) for the experiments. Experimental data shows that cooling performance was improved at higher mass flow rate and both distilled water and vegetable oil is a good coolant material.

Abstract: The main goal of this work is to investigate the performance of zirconia toughened alumina (ZTA) and ZTA reinforced with magnesium oxide (MgO) used as cutting insert in end milling of AISI 1018 steel with hardness of 27 HRC. Performances of the cutting insert were compared according to tool life and surface finish of workpiece. Insert flank wear that indicates tool life was studied carefully using Optical 3D Surface Metrology while surface roughness values were evaluated using Surftest Sufrcom 130A. The cutting inserts failed to exhibit good performance in end milling operation. However, wear condition and magnitude of the ZTA reinforced with MgO insert was slightly better than ZTA insert. Addition of MgO may increase wear resistance.

Abstract: Plastic Leaded Chip Carrier (PLCC) package has been emerged a promising option to tackle the thermal management issue of micro-electronic devices. In the present study, three dimensional numerical analysis of heat and fluid flow through PLCC packages oriented in-line and mounted horizontally on a printed circuit board, is carried out using a commercial CFD code, FLUENT^TM. The simulation is performed for 12 PLCC under different inlet velocities and chip powers. The contours of average junction temperatures are obtained for each package under different conditions. It is observed that the junction temperature of the packages decreases with increase in inlet velocity and increases with chip power. Moreover, the increase in package density significantly contributed to rise in temperature of chips. Thus the present simulation demonstrates that the chip density (the number of packages mounted on a given area), chip power and the coolant inlet velocity are strongly interconnected; hence their appropriate choice would be crucial.

Abstract: This study is concerned on chemical modification of bagasse fiber (BF) filled polypropylene (PP) composites compounding using two roll mill. The fibers were chemically modified with different chemical treatment (alkaline, acetic acid and silane coupling agent). Effect of chemical modification towards BF/PP composites was evaluated by tensile test and flexural test. The chemical modification efficiency was verified by Fourier Transform Spectrometer (FTIR) analysis. From FTIR analysis, there is an increase on intensity on acetyl group (C-H) indicated the existing of chemical bonding between PP and BF. Chemical modified composites increased the mechanical behavior. Composites that modified with acetylation (acetic acid) shows better mechanical properties compared to others.

Abstract: Well-aligned ZnO nanorod arrays with different average diameters were grown on silicon (100) substrates by hydrothermal method via the precursors of zinc nitrate hexahydrate (Zn (NO3)2 .6H2O) and Hexamethylenetetramine (C6 H12N4) with equal molar concentration at 0.025 mol/l and 0.05 mol/l. The ZnO nanorods were characterized by X-ray diffraction (XRD) and field emission Scanning electron microscopy (FE-SEM). XRD results indicated that all the ZnO nanorods were preferentially grown along [000 direction (c-axis). field emission Scanning electron microscopy images showed that the well-faceted hexagonal ZnO nanorods were grown vertically from the silicon (100) substrates.

Abstract: Torrefaction is a thermal treatment step in a relatively low temperature range of 240-300°C, which aims to produce a higher energy biomass in terms of low heating value (LHV) and light weight properties. Biomass in wood (sawdust) was used in this work due availability in tropical climate and relatively cheap. LHV of torrified sawdust was found to be increases as heating temperature increased, in absence of oxygen content. This is enhanced by way of decomposing the hemicelluloses fraction. The thermogravimetric analysis (TGA) records the changes occurred in fixed carbon, volatile and ash in which it was recorded that an increase of fixed carbon and ash is seen in the increases of temperature and a decrease of volatile is vice versa. The study provides a clearer picture of the result obtained from TGA and HHV which improvise the biomass into higher energy output.

Abstract: The aim of this study is to investigate the effect of filler loading on the sorption and solubility of Simulated Body Fluid (SBF) of self-prepared micro dental resin composites. The prepared resin composite was based on silica (SiO₂) particles and bisphenol-a-glycidyl methacrylate (Bis-GMA) as a base monomer and triethylene glycol dimethacrylate (TEGDMA) as a co-monomer. The filler was mixed with monomers, in proportions of 40, 50 and 60 wt.%. A resin matrix containing 0 wt.% filler was used as the control composition to evaluate the effect of filler loading on the sorption and solubility of SBF. The experimental methods were based on the procedure mentioned in the ISO 4049 (2009) standard for dentistry-Polymer-based restorative Materials. The sorption and solubility of resin matrix/SiO₂ composite decreased gradually as the filler loading increased. The increase of filler loading showed significant differences in the sorption and solubility as tested by ANOVA (P = 0.000).