Key Engineering Materials Vols. 471-472

Abstract: The need and development of cleaner and greener alternative technologies using the heterogeneous catalytic system in the synthesis of fuel is very important. In this work hydrogen production via steam reforming of glycerol (C3H8O3) was carried out over nickel supported on hydroxyapatite [Ca5(PO4)3(OH)] as a biomaterial catalyst. The time reaction is carried out for 240 minutes in a fixed-bed reactor fixed at 600 oC and atmospheric pressure with the water-to-glycerol feed ratio of 8:1. Catalysts were prepared by mean of impregnation and sol-gel method with varied nickel loadings (3, 6, 9, 12 %) on hydroxyapatite. The catalysts were characterized by BET surface area, X-ray diffraction, and SEM-EDX techniques. It is found that 3 wt% of nickel loading prepared via sol-gel method exhibit the higher hydrogen production rates (63.62 % - 74.16 %) in comparison to the other nickel loadings.

Abstract: The present research is undertaken to study the influence of Li on the tensile properties of Al-15%Mg2Si metal matrix composite. The tensile test results show that adding 0.15%Li to the composite raises the UTS and elongation values, insignificantly. In the point of fracture behaviour of the composite, the addition of 0.15%Li converts the fracture behaviour from brittle, with cleavage facets, to ductile, with fine ductile dimples.

Abstract: Removed at Authors Request

Abstract: A study was conducted with the objective of gathering the information through flexural (three-point bending) testing. This research presents the testing results concerning the mechanical properties, modulus of elasticity (MOE) and modulus of rupture (MOR) of natural fiber reinforced composite. Resin were used as a matrix and untreated wood fibres contents 14% by weight as a filler treatment parameters to obtain better compatibility involving wood fibres Sawdust (SW) and Chipwood (CW) and epoxy. The feasibility of processing the composite prepared manually from waste wood and epoxy using open molding was investigated. The tests that have been conducted are in according to ASTM (D790-97) for flexural properties test method. Statistical analysis using ANOVA one way and two way showed that the differences of results obtained from those SW and CW fiber composite samples are significant, which confirm a very firm mechanical performance of the composites through flexural tests. This shows the producing a good quality of SW and CW fibre composite which maybe can use for furniture utilities.

Abstract: In this study, waste wood product obtained from the timber industry originating from various type of wood has been investigated. Research work carried out on the three different sizes of fiber derived from the sawdust (SW) and chip wood (CW). The SW and CW fiber and epoxy resin were blended together respectively using hand tools machine, all specimens of fiber composite were prepared accordance to the ASTM standards. Tensile and morphological properties provide an excellent measure of the degree of reinforcement provided by the fiber to the composite. The tensile modulus increased with the filler size from coast to rough of composites both SW and CW but decreases steadily with the wood–fiber size from rough to soft content. Statistical analysis using one way and two ways analysis of variances (ANOVA) showed that the differences of results obtained from those SW and CW fiber composite samples are significant, which confirm a very firm mechanical performance of the composites through tensile tests. This shows the producing a good quality of SW and CW fibres composite which maybe used for home furniture utilities.

Abstract: For the widespread use of adhesive joints an exact and reliable prediction of the strength is mandatory. In this work, a new approach to assess the strength of single lap joints is presented. The approach is based on the hybrid criterion as postulated by Leguillon in the framework of finite fracture mechanics. It strictly combines a consideration of an energy release balance and a fulfillment of a strength criterion. The present work is based on a simple model of the joint behavior and assumptions about crack initiation. From the stress distribution of the classical shear lag theory an incremental energy release rate is derived and is used to formulate the optimization problem of the failure load. The resulting predictions of critical failure loads are compared to experimental results of single lap joints. It is shown that the new approach is able to physically describe crack formation and the corresponding critical load within the framework and limitations of the underlying assumptions and simplifications. The work closes with a discussion of the limitations and an outlook on possible improvements of the underlying models and assumptions.

Abstract: In this study, solidification analysis of metal matrix composite, aluminium-11.8% silicon alloy matrix reinforced with titanium carbide particulates is performed. Sand casting method is used as the manufacturing method to produce the specimens. Thermal measurements during the casting process are captured and solidification graphs are plotted to represent the solidification characteristic. Solidification analysis is performed by interpreting the solidification graphs. Parameters such as; the nucleation of primary alpha phase temperature, liquidus arrest temperature, liquidus undercooling, eutectic growth temperature and solidification time are presented. The results show that introduction of second phase particulates into a matrix alloy have affected the various time and temperature parameters of its solidification properties.

Abstract: In this paper, a numerical simulation on a new fabrication miniature composite fuselage structure- a woven composite laminated with an adhesively bonded butt joint under the axial compression loading is presented. A FEA via Abaqus/Explicit was utilized to capture the complete compressive responses to predict the crushing behaviour and its mechanical strength from the initial compression loading till its final failure mode. A woven C-glass fiber/epoxy 200 g/m2 composite laminated [908] with the orthotropic elastic material properties is modeled as a continuum composite layup in the proposed numerical model. The adhesively bonded joint progression was modeled using the cohesive element technique. The proposed model was used to observe the crushing load and collapse modes under the axial compression impact. The finite element results showed a good agreement with the experimental results under the actual quasi-static tests. The validation code was extended to further undergo parametric studies in order to visualise the effect of angle orientations and special laminate cases as to attain the optimum design criteria for the proposed composite structure.

Abstract: Regarding conservation policies of natural forests and environmental concerns forced wood composite panel manufacturers to consider using other lingo-cellulosic resources. Plantation fast growing species such as poplar, eucalyptus , paulownia and others is already started in many countries. Fast growing trees usually produce light wood with low strength so manufacturer has low certainty on using them for manufacturing wood composite panel. This study oriented toward examination of application of paulownia wood particle for manufacturing wood composite panel. In this study, specific press pressure at two levels (30 bar and 40 bar) , and press time at two levels (8 and 12 minutes) were used as independent variables. 12 experimental panels were made in laboratory. Mechanical properties such as MOR, MOE and IB were evaluated. Results showed that panels made at press pressure of 40 bar and press time of 12 minutes presented the highest MOR (41.28 MPa) and MOE (4128 MPa) but the highest IB (1.14 MPa) was observed in composite panels made at press pressure of 30 bar and press time of 8 minutes. Based on EN Standard MOR of Particleboard ranged from 12 to 15 MPa and MOE ranged from 2500 to 3000 MPa and IB ranged from 0.4 to 0.6 MPa . Comparing Above mentioned values with EN values it can be seen that Mechanical properties of wood composite panels made from paulownia are much higher than EN standard. These results are very good ground to focus on fast growing species such as paulownia to compensate wood raw material shortcoming in wood industry.

Abstract: Kenaf fiber was treated with alkaline to reduce lignin content and tested under Fourier transform infrared spectroscopy (FTIR). FTIR result showed that peak at 1146 cm-1 which is acetyl group of lignin was reduced in treated fiber while disappearing of carbonyl group in treated kenaf fiber at 1750cm-1 was significantly shown compared to untreated kenaf fiber. Treated fiber undergoes mechanical size decrement process by high pressure homogenizer with 500bar pressure and 60 passes. Transmission Electron microscopy (TEM) was used to determine size and distribution of fiber. Moreover, morphology of nanofiber was observed under scanning electron microscope (SEM). Nanofiber (3%, 5%, 8% and 10%) was mixed with PLA using internal mixer and then compressed with hot pressed to produce specimen for tensile test. Tensile strength and tensile modulus of nanocomposite with 10% of nanofiber increased by 30% and 85% respectively compared to pure PLA.