Conference Publications
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PublicationEffects of diameter on copper pillar with solder cap interconnections during reflow soldering process(Springer, 2023)Recently, the copper pillar with solder cap interconnection has been introduced as an alternative for the solder bump interconnection to tackle the limitations, such as the collapsing nature of the solder bump and larger pitch size. This paper presents an effective simulation tool to evaluate the effects of different diameters of the copper pillar with solder cap during the reflow soldering process. A three-dimensional numerical approach is used to investigate the thermal behavior of the copper pillar with solder caps with different diameters. The interconnection bump diameters are 150, 200, 250, 300, and 350 μm. The model is developed and meshed using the Computational Fluid Dynamics (CFD) software. The temperature distributions of the copper pillar with solder caps with different diameters during the reflow soldering process are predicted. The paper aims to provide an understanding of the effect of diameters on the temperature distribution of copper pillars with solder caps during reflow soldering.
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PublicationIsothermal oxidation behavior of Ni-based Fe–Ni–Cr superalloys: role and effect of Nb alloying element(Springer, 2023-07)The isothermal oxidation of heat-treated Ni-based Fe–Ni–Cr superalloy at 500 ℃ was studied to further investigate the role and effect of Nb alloying element during oxide scale formation. The Ni-based Fe–Ni–Cr superalloys underwent a heat treatment process at two different temperatures, that are, 950 ℃ and 1100 ℃, for 3 h of soaking time, followed by water quenching. Heat-treated sample at 950 ℃ exhibited fine grain size, while heat-treated sample at 1100 ℃ exhibited coarse grain size. The heat-treated Ni-based Fe–Ni–Cr superalloys were subjected to an isothermal oxidation test at 500 ℃ for 500 h exposure. The oxidized heat-treated Ni-based Fe–Ni–Cr superalloys were analyzed in terms of oxidation kinetic, oxide phase formation and oxide surface morphology. The oxide phases were analyzed by using XRD technique. The surface morphology was examined by using SEM, FESEM and EDX techniques. Both oxidized heat-treated Ni-based Fe–Ni–Cr superalloys’ samples followed a parabolic rate law, indicating a diffusion-controlled oxide growth mechanism. Several oxide phases were formed on the alloy surface after exposures at 500 h. The surface morphology of oxidized samples at 300 h exhibited the formation of continuous oxide scale with distributed overgrown Nb-rich oxides. Nb-rich oxides were formed on coarse-grained heat-treated alloys that developed excessively large Nb-rich oxides. This phenomenon will initiate a crack that propagates around the oxide.
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PublicationEffect of pulse current amplitude on corrosion protection of mild steel in the atmospheric environment(Springer, 2023)Atmospheric metal corrosion affects the appearance and life span of iron-based metals. There are several methods for dealing with atmospheric corrosion, but none are perfectly ideal. Pulse Current Prevention (PCP) is a new method for atmospheric corrosion protection. Mild steel samples were studied using PCP for 14 days in a semi-sealed container. The pulse current is 50 Hz, 50% duty cycle, with different amplitudes of 2, 5, and 7 V. Amplitude effectiveness in the PCP technique is determined by morphological observation and image analysis technique. According to the findings, the use of pulsed current can prevent atmospheric corrosion on the steel sample. The amplitude of pulsed current has a major impact on atmospheric corrosion protection. The amplitude of 2 V is inadequate to create the necessary negative charges for steel surface protection. In the meantime, a 7 V amplitude produces overprotection, which exacerbates atmospheric corrosion deterioration. The meaningful finding is that 5 V is found to be a fairly good amplitude parameter for atmospheric corrosion prevention. Nonetheless, it needs to be investigated further to give optimal protection.
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PublicationSynthesis of Zeolite from rice husk ash(Springer, 2023)Rice husk ash (RHA) is used as the starting material for the synthesis of zeolites. In this study, alkaline hydrothermal treatment has been chosen for the zeolite conversion. Sodium hydroxide solution is used as the activation for the synthesis of zeolites. Two parameters affecting the hydrothermal synthesis of zeolites were investigated, including sodium hydroxide concentration (1 and 2 M) and reaction temperature (60, 80, and 100 °C). The produced samples' chemical composition and crystalline phase were investigated using XRF and XRD. The result showed that the zeolite obtained from 2 M of NaOH solution under 80 °C of reaction temperature was gismondine.
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PublicationInvestigation on the effect of electrospinning parameters: voltage and flow rate on PVDF fiber(Springer, 2023)Polyvinylidene fluoride (PVDF) is a high purity thermoplastic fluoropolymer and high-capacity polymer that is employed in the electronics, space, and aeronautics industries. Electrospinning parameters have a considerable impact on the morphology, crystallinity, and electrical conductivity of PVDF fiber. Voltage and flow rate are the electrospinning parameters investigated in this study. As a result, the goal of this study is to investigate the effects of various voltages and flow rates on PVDF electrospun fiber. Electrospinning is the simplest and low-cost method to produce PVDF fibers by dissolving PVDF in solvent N, N-Dimethylformamide (DMF). About 15 wt% PVDF solution was used. Electrospinning parameters used were varied applied voltages 15 and 20 kV, flow rates 0.8, 1.0, 1.2, and 1.4 ml/h. Tip-to-collector distance was fixed at 15 cm. Scanning electron microscope (SEM), four-point probe, and X-ray diffraction (XRD) were performed to determine the morphology, electrical conductivity, and crystallinity phase of electrospun PVDF fibers. The SEM analysis concluded that bead formation occurs at higher flow rate and higher voltage. With higher flow rates and lower applied voltage, the fiber's thickness increases. XRD analysis shows that shift peak is observed among all fibers due to short electrospinning time which leads to insufficient thickness of electrospun mat, which affects the mechanical properties of fibers and causes peak shift. Four-point probe analysis concluded that the average conductance increases sharply as flow rate increases and the average resistance decreases. Also, as applied voltage increases, average conductance decreases and the average resistance increases.