Paper Submission and Review System

Abstract: In this present work, the effects of recycled aluminum scraps on the impact and hardness properties and microstructures with a melting process are studied. The method was conducted to determine an impact toughness by Charphy pendulums; hardness materials by Vickers's test; and chemical composition by spectroscopy. Four types of aluminum scraps have been recycled using a metal casting process. They are beverage cans, aluminum profile bar waste, gasoline engine piston, and scrap pans. The results show that the maximum hardness obtained is 54.13 VHN on the material of the gasoline engine piston. The lowest hardness is 26.88 VHN which is obtained for pan aluminum recycle. The highest impact test result is obtained on an aluminum pan material which is 40.3 J/mm2 in average and the lowest value obtained is on the gasoline engine piston material which is 1.7 J/mm2 in average.

Abstract: One aspect that needs to be considered in the application of asphalt pavement is the fact that asphalt is a non-renewable resource which requires constant maintenance throughout its lifetime. Thus, developing a mix with asphalt contents reduced to the minimum is a challenge in and of itself. Latex, in this case, would seem to be potentially viable additives. The aim of this research is to investigate the effects of using latex as an additive to minimize the use of asphalt in asphalt concrete wearing courses (ACWC). Four varying amounts of latex were mixed with asphalt at 0%, 2%, 4%, and 6% of the total weight of an asphalt binder. A wet process was then employed to blend the mixtures together. Afterward, the latex-asphalt mixtures were added to an aggregate to form various mixtures ranging from 5% to 7% of the aggregate and the incremental weight of 0.5% of the latex-asphalt ACWC. For each latex-asphalt-aggregate mixes, the optimum binder content was determined based on stability, flow, Marshall quotient, voids in the mineral aggregate (VMA), voids in the mixture (VIM) and voids filled by the binder (VFB). The results of this experiment indicated that the addition of latex reduces the need for asphalt contents.

Abstract: In this research, alkali treated zallaca fibre reinforced with high density polyethylene (HDPE) composites are subjected to water immersion tests in order to study the dimensional changes and flexural properties of composites. Composites were frabricated using compression molding method with zallaca fiber content of 30% vt. Composite specimens were immersed under three different solution included distilled water, sea water and acidic solutions for 2 months at room temperature. The highest dimensional changes was recorded for composite immersed in seawater followed by acidic solution and distilled water. The dimensional changes of Zallaca fibre reinforced HDPE in different solution were found to follow a Fickian behaviour. Alkali treated fiber composites after immersion has lower results both in dimensional changes and its slope than untreated fiber composites in different aquaeous environment. The severe degradations are observed by using Scanning Electron Microscopy (SEM) that showed microcracks growth, and degradation of interfacial region between fiber and matrix. Flexural properties of composites decrease after immersion stage in different values.

Abstract: One of the surface treatments to improve the hardness of the surface is by ion implantation process. This paper presents an equation to predict the surface hardness with the variable of the process time in ion implantation surface treatment. The hardness of three surfaces data were collected experimentally from various process times, i.e. 140 minutes, 280 minutes and 560 minutes. Lagrange polynomial interpolation was then used to generate quadratic mathematical formula of the surface hardness based on experimental data. The verification results show that the proposed equation accurately predict the surface hardness of commercially pure (cp) titanium under ion implantation process with the error less than 0.5 %. This equation can be used to set the appropriate treatment process time to achieve the expected surface hardness without costly trial experimental settings.

Abstract: The low cost of ABS polymer and natural polymer chitosan offer attractive chemical and physical properties for direct methanol fuel cells (DMFC). Blend membrane made of ABS and chitosan were synthesized and characterized for water uptake, swelling degree and ion exchange capacity (IEC) and methanol crossover to investigate the applicability in DMFC. This membrane was also assessed for its intermolecular interactions and thermal stability using FTIR and TGA compared to the pristine membrane. The water absorption and IEC values were affected by membrane network structure. The polymer blend had better thermal stability and a reduction of methanol permeability, this indicated the viability of utilization these materials as polymer electrolyte membrane in DMFC.

Abstract: Inorganic polymer materials known as geopolymer-based materials are always interesting topics for researchers. Geopolymer is environmentally friendly material which has been potential applications for many different fields such as technical materials, building materials, insolation or refractories, and others. This study used ash of brickyard (AB) as a raw material for geopolymerization process to develop novel materials with high porosity. AB is industrial waste of the brick factories that need to be managed to reduce their negative impact to the environment. AB contains high alumino-silicate resources were mixed with sodium hydroxide solution for 10 minutes to obtain the geopolymer pastes. Sodium hydroxide solution was used as an alkaline activator to form geopolymer paste. The geopolymer paste was filled into 5-cm cube molds according to ASTM C109/C109M 99, and then cured at room temperature for 28 days. These products were then tested for compressive strength, volumetric weight, and water absorption. Results indicated that the material can be considered lightweight with a compressive strength at 28 days that are in the range of 8.1 to 15.4 MPa, volumetric weight around 600kg/m3 and water absorption is under 210.65 kg/m3. The properties of geopolymer products were also determined by analytical techniques that included mineral composition by X Ray Diffraction (XRD) and microstructure by scanning electron microscope (SEM).

Abstract: Ultimate tensile strength (UTS) becomes a primary concern in direct recycling of metal chips. This study investigates the influences of preheating temperature, preheating time and volume fraction of alumina on the tensile strength performance. The parameters of temperature, time and volume fraction of micro alumina were varied between 450 - 550 oC, 1 - 3 hours and 5 - 15% respectively. The full factorial design with center point analysis was employed to analyse the effect of process variables on the response. A total of 19 experimental runs were performed through the hot extrusion operation. The preheating temperature and volume fraction were identified as the key variables affecting the UTS. An optimum UTS was obtained for the profile extruded at 550 oC, 3 hours duration and 5% volume fraction of alumina.

Abstract: The combination of heat treatment, addition of grain refiner and ECAP processing is used to improve mechanical properties and wear resistance of A356 Al alloys with 1.5 wt.% TiB2. The alloys were grouped into as-cast and pre-ECAP annealing. The alloys were characterized with hardness and wear testing, optical microscopy and SEM. The ECAP processing was done through BA route for 4 passes and it improved hardness, distribution of TiB2 and Si particles in the aluminium matrix and increased wear resitance of pre-ECAP annealing specimen.

Abstract: The stress distribution and deformation formed by various loading conditions are a crucial thing to be considered during design. Stress and deformation maximum area should be a primary concern, and this study will discuss the stress analysis and displacement of the bike frame (T-I profiles) through the Finite Element Method (FEM), then five scenarios loading conditions have been applied. Loading conditions are the static start-up, steady-state pedaling, vertical-horizontal impact, and rear wheel breaking. Cross-section of bike frame comprises into two forms. There are “T” profile on the main frame and “I” profile on stay. The results show for the loading conditions reach maxima respectively of 18.4, 21.98, 36.83, 14.3 MPa (Von Mises stress). Maximum displacement for the different loading conditions are 0.11, 0.13, 0.23, 0.041, and 0.018 mm.

Abstract: The Abaqus software was used to simulate creep behaviour of a cylindrical tube of Sanicro-25 austenitic steel under an internal pressure of 11.3 MPa at a uniform temperature at 750 °C. The data used for the simulation input were obtained from the experimental data of a previous work. The hidden information of material parameters was estimated from the shape of creep strain versus time plots obtained from the experimental data. The validated results between the simulation and the experimental data produced the material parameter of the creep power law which were set at 2.6 x 10-22 for the power law constant and 9 for the stress exponent. The parameters were further used to explore the stress and strain inside and outside of the tube wall and the thickness changes of the tube wall.