Kenaf is a non-woody plant, which has high potential fiber to be used as polymer matrix reinforcement. Different compositions of kenaf fiber as bio reinforcing material at different fabrication process parameters will produce different biocomposite properties. This study uses kenaf fibers in the composition of 10, 20, and 30 wt.% as reinforcing material. Kenaf fiber and epoxy resin were mixed based on predetermined compositions, stirred using a mechanical stirrer at 200 rpm for 10 minutes. Then the mixture is poured into a mold and placed on a hot press machine. Pressure of 50 kg/mm2 for 30 minutes at 150°C is used to produce kenaf fiber/epoxy biocomposite. The result showed that the increasing of kenaf fiber content in the matrix is succeeded to increase the flexural and impact strength of the biocomposite kenaf fiber/epoxy produced. The highest flexural strength (136 MPa ) and highest impact strength (180 KJ/m2) were obtained at a composition of 30 wt.% Kenaf fiber.
This paper presents a study of experimental performance of solar still using reflector to produce fresh and salt water in the climate of Padang city, Indonesia. The solar collector is equipped with a reflector placed on the top of the cover with slope of 30º. Test results show that using reflector can increase temperature in the basin. Freshwater productivity also increases and speeds up time in producing salt. Average daily freshwater productivity increased by 16.8% during the testing period by adding reflector compared to solar still without reflector
This study aims to investigate the influence of shot penning on fatigue crack growth rate of chemical milling product Al 2524-T3 which have been stretched. This alloys were stretched beyond yield stress, namely 1%, 3% and 5% of each, and then performed chemical milling process of one side. The etching used in chemical milling process were NaOH+Na2S+H2O solutions with certain concentration. The surface was performed shot penning process with varying intensity of 0.03 A, 0.05 A and 0.07 A, respectively. These material were then tested its crack growth rate. The crack growth rate tests were performed under 20% stress level, stress ratio of 0.3 and at frequency 7-13 Hz. The average of crack propagation data against the cycle number were processed using an incremental method, in accordance with ASTM E647 standard, to obtain crack growth rate curve (da/dN vs. ΔK). The results show that the increase of shot penning intensity has no significant effect on the fatigue life, with the growth average of 4,5%. The highest increase occurred at the shot intensity of 0.03 A, 0.2 times its chemical milling, while the lowest decrease occurred at the shot intensity of 0.07A, 0.012 times its chemical milling. The crack retardation effect at the beginning of the crack plays a role in reducing the crack propagation rate.
Optimization of molding parameter on the flexural strength of carbon black/graphite/epoxy (CB/G/EP) nanocomposites using Taguchi method was studied. Three molding parameters was chosen in this study which are molding temperature, molding pressure and molding time. Experimental trials were carried out based orthogonal array design using those three parameters. The results were analyses using the signal to noise (S/N) and analysis ofvariance (ANOVA). Flexural strength of the CB/G/EP nanocomposites increases from 56.23 MPa to 65.11 MPa usingoptimize parameter obtained from the analysis method. These results shown that the Taguchi method is successfully to get optimum parameters of molding parameters to produce CB/G/EP nanocomposites.
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