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PublicationSawdust short fiber reinforced epoxidized natural rubber: insight on its mechanical, physical, and thermal aspects(Tech Science Press, 2020)In this work, Epoxidized natural rubber/sawdust short fiber (ENR-50/ SD) composites at different fiber content (5, 10, 15 and 20 phr) and size (fine size at 60–100 μm and coarse size at 10–20 mm) were prepared using two-roll mill and electrical-hydraulic hot press machine respectively. Curing characteristics, water uptake, tensile, morphological, physical, and thermal properties of the composites were investigated. Results indicated that the scorch time and cure time became shorter whereas torque improved as SD content increase. Though the decline of tensile strength and elongation at break values, modulus, hardness and crosslinking density have shown enhancements with the increasing of SD content. The water uptake percentage of all samples has shown an increasing as SD content increase. However, the low SD content, particularly fine size have presented lower water uptake. The temperature of weight% loss (5 and 50 wt% loss) of 5 phr SD (low content) have recorded higher temperature compared to 20 phr SD (high content) in the rubber composites, which indicated higher thermal stability. The fine size of SD has recorded better overall properties than SD coarse size at same loading in the rubber composites.
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PublicationModification of Polylactic acid/ Halloysite Bionanocomposites using electron beam radiation: physical, barrier and thermal properties(Trans Tech Publications Ltd., 2020-07)This study aimed to develop novel Polylactic acid/ Halloysite (PLA/ HNTs) films which showed better properties when they were used for food packaging. They also displayed better mechanical, barrier, morphological and structural properties when the researchers analysed the impact of the electron beam irradiation on the nanomaterials. They prepared PLA-based nanocomposites containing 5 % w/w of HNTs using the solution casting process. These nanocomposites were further exposed to different ebeam doses (i.e., 0, 20, 40 and 60 kGy). The researchers assessed the effect of the electron beam irradiation on the various properties of the PLA. All the composites showed a homogenous dispersion and distribution of the HNTs in this PLA matrix. Results indicated that the nanocomposites showed better barrier properties in comparison to the neat PLA. Furthermore, the ebeam irradiation could increase the glass-transition temperature and lead to the development of more crosslinks, which increased the degradation temperature and hydrophilicity of the nanocomposites. In this study, the researchers showed that the PLA/HNTs films were effective materials that could be used for the electron beam processing of the pre-packed foods. The best effect was noted for the 20 kGy dosage which was used in the study.
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PublicationValidation of foam filled tube model and optimization result using Weibull distribution(LAJSS, 2020)Passenger safety and low fuel consumption rate are the most important factors that need to be considered when designing modern transportations. This study validates the crash behavior and optimum values of foam-filled structures under the dynamic oblique impact using the Weibull distribution. The optimization method aimed to absorb maximum energy with minimum peak crushing force. Furthermore, the metamodel and optimization techniques such as RBF and NSGA-II were used to ensure accurate validation of the Weibull distribution method. The result showed that the finite element model is comparable to the experimental data in the reference, while the metamodel method, which is directly verified, affects optimization results. The Weibull distribution method shows that the optimum value and the simulation have good accuracy or R2 > 0.85.
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PublicationHeat transfer and deformation analysis of flexible printed circuit board under thermal and flow effects(Emerald Publishing, 2020)Purpose: The purpose of this study is to investigate heat transfer and deformation of flexible printed circuit board (FPCB) under thermal and flow effects by using fluid structure interaction. This study simulate the electronic cooling process when electronic devices are generating heat during operation at FPCB under force convection. Design/methodology/approach: The thermal and flow effects on FPCB with attached ball grid array (BGA) packages have been investigated in the simulation. Effects of Reynolds number (Re), number of BGA packages attached, power supplied to the BGA packages and size of FPCB were studied. The responses in the present study are the deflection/length of FPCB (δ/L) and Nusselt number (Nu). Findings: It is important to consider both thermal and flow effects at the same time for understanding the characteristic of FPCB attached with BGA under operating condition. Empirical correlation equations of Re, Prandtl number (Pr), δ/L and Nu have been established, in which the highest effect is of Re, followed by Pr and δ/L. The δ/L and (Formula presented.) were found to be significantly affected by most of the parametric factors. Practical implications: This study provides a better understanding of the process control in FPCB assembly. Originality/value: This study provides fundamental guidelines and references for the thermal coupling modelling to address reliability issues in FPCB design. It also increases the understanding of FPCB and BGA joint issues to achieve high reliability in microelectronic design.
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PublicationNumerical study on the effect of mean pressure and loop's radius to the onset temperature and efficiency of traveling wave termoacustic engine(Universitas Muhammadiyah Magelang, 2020)The thermoacoustic engine can be a device to convert waste heat energy in the engine car become useful energy such as for charging battery in car or Air conditioner of the car. This work can be done by experimentally and numerically. There are some parameters that have an impact on the performance of the engine. They are geometry of the engines, working fluid, and mean pressure. The performance of the engine depends on the efficiency and the heating temperature. In the car, waste heat energy is not high enough. Therefore, we need to utilize the low heating temperature to be converted into useful energy. This study contributes to numerically the effect of mean pressure and loop’s radius of the regenerator on the onset temperature and the efficiency of traveling wave thermoacoustic engines. The application that is used to solve numerical problems is fortran95. There are two codings that are used in fortran95. They are stability limits and efficiency codes. The lowest onset temperature that achieved is 153˚C with efficiency up to 38.1% that can be reached when the mean pressure is 4.0 MPa and the loop's radius is 5 cm. This result indicated that we can use low heating temperatures from waste heat of engine car to turn on electronics equipment inside the car.
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