Jurnal Penelitian Fisika dan Aplikasinya (JPFA)

High Preferred Orientation on c-axis of ZnO:GO Crystal Film Synthesized Under Electric Field

Annisa Nur Rahmawati — 2023-12-30

ZnO nanostructures show a wide range of applications as active materials in optoelectronic devices. The unique structures in 1-dimensional (1D) in combination with other potential materials (such as graphene-based) can increase several device performances. This research aims to observe the influence of an additional electric field (induced by different voltages of ±1 kV) during the growing process of the zinc oxide (ZnO): graphene oxide (GO) crystal. The ZnO:GO layers were prepared via the self-assembly method in 2 steps; the first was seed layer preparation by dip coating technique using Zn (CH₃COO)₂.2H2O and 0.5 (wt%) of AlCl₃ as precursor and dopant, respectively. Secondly, growing ZnO rods using Zn (NO₃)₂·6H2O as precursor, 0.5 (wt%) GO (dispersed in water) as dopant materials, and hexamethylenetetramine (HMTA) as complexing agent. Applying an external field during self-assembly accelerated the ZnO hexagonal wurtzite crystal formation in a vertical growth direction, increasing the aspect ratio (L/d) of ZnO:GO rods. The direction of the applied external field affected the structure and morphology of the ZnO rods, which relates to ions and seed layer surface polarity during the synthesis process. The addition of an external field during the growing process induced the orderly alignment of ZnO rods, controlling growth perpendicular to the basal plane. This research has a significant scientific impact, elucidating the methods to control the 1D morphology of the ZnO growing process, which is closely related to the surface polarity properties of a material.

Enhanced Performance of Solid Polymer Electrolyte Separator Lithium Battery with Cellulose Acetate From Empty Palm Fruit Bunch Coated Al2O3-Polyacrylic Acid

Delovita Ginting — 2023-12-30

As lithium battery technology improves, it becomes more important to have solid polymer electrolyte dividers that work better. The objective of this study is to enhance the efficiency of solid polymer electrolyte separators in lithium batteries. This research aims to expand the limits of innovation in hybrid separator development by utilizing empty palm fruit bunches (OPFEB) as a plentiful source of cellulose acetate. This approach enhances ion transfer by increasing the number of pores in the separator. However, there are challenges to achieving the desired levels of optimal ionic conductivity. In order to address these constraints, this study presents a novel Al₂O₃-PAA inert ceramic oxide coating treatment that is applied to the separator by a spin coating technique. An electron microscope was utilized to observe the pore structure of the separator. Additionally, the separator underwent physical, mechanical, thermal, and cyclic voltammetry tests. The findings of this research indicate a significant increase in the physical properties, particularly the porosity and mechanical strength. The thermal shrinkage of the Al₂O₃-PAA coated separator is below 10% when exposed to a temperature of 140 ^oC for 30 minutes. The Cyclic Voltammetry test results demonstrate a pronounced loop curve, indicating an improvement in the ionic conductivity of the Al₂O₃-PAA coated separator. The findings of this study provide a method to enhance the efficiency of separator performance at high temperatures while maintaining safety and long battery life.

Reconstruction of the Indian Ocean Tsunami in 2004 in Sabang Based on the Current Land Cover for Tsunami Evacuation Sites Recommendations

Abdi Jihad — 2023-12-30

Sabang City has grown in term of city’s population as well as the tourism activity. The development also meant there are more area that has been used when compared to the time before the 2004 tsunami. This research was developed to re-identify tsunami-prone zones with the current land cover condition in Sabang City and to provide recommended safe locations, alternative evacuation routes, and additional evacuation sites. We used Cornell Multi-grid Coupled Tsunami Model (COMCOT) to carried out the tsunami simulation added with updated land cover to provide more accurate simulation model. The simulation pointed out several tsunami hazard zones in Sabang City, such as Balohan, Kuta Ateuh, and Iboih with expected tsunami heights to be more than 3 meters and arrival time less than 60 minutes. Those areas then surveyed to develop recommendations for tsunami risk reductions. The recommendations included nine additional evacuation buildings are proposed, three sites in each zone. Another recommendation is in form of evacuation routes in each zone to complement existing routes stated in RTRW document.

Altering Coconut Shell Biomass to High-Ordered Graphitic Carbon with Nickel Catalyzation

Biaunik Niski Kumila — 2023-12-31

Graphite is a carbon-based material potentially utilized in numerous applications, such as electrodes for supercapacitors, lithium-ion batteries, and absorbers for water treatment. Biomass graphite is a beneficial candidate for low-cost yet valuable graphite. In this work, coconut shells, the abundant materials with high carbon contents, were successfully transformed into valuable coconut shell graphite (CSG) using metal catalytic graphitization with nickel as a catalyst at low-temperature conditions of ~1200 °C. Nickel concentration varied between 2 mmol, 3 mmol, and 5 mmol per gram of carbon. The samples were further examined using X-ray diffraction (XRD), Raman Spectroscopy, and Transmission Electron Microscope (TEM). The high graphitization degree of ~ 72 % was confirmed by X-ray diffraction analysis. That was further supported by the high-ordered stacking carbon layer that appeared in HR-TEM images. Meanwhile, Raman spectroscopy confirms that nickel impregnation diminished the structural defect of samples and increased the sp²-carbon bond indicated by its rise of IG/ID. The IG/ID values of CGS and CGS-Ni_5mmol are 0.86 and 0.92, respectively.

A-Site Doped in Perovskite La(1-x)Bax/2Srx/2Mn0.4Ti0.6O3 (x = 0, 0.1, and 0.3) for Absorbing Microwave Material

Sitti Ahmiatri Saptari — 2023-12-30

Microwave radiation can have harmful effects on our bodies. With increased exposure due to online activities, it is essential to use absorber materials like perovskite manganate to reduce radiation. In this study, perovskite manganate La_(1-x)Ba_x/2Sr_x/2Mn_0.4Ti_0.6O₃ (x = 0, 0.1, and 0.3) was synthesized using the sol-gel method. X-ray diffraction (XRD) analysis revealed that the two samples were multi-phased, LaMnO₃ and La₂Ti₂O₇, and were formed, exhibiting a rhombohedral crystal structure (R -3 c). Morphological characterization of the sample surface using a Scanning Electron Microscope (SEM) showed that as doping increases, the grain size decreases from 282.02 to 245.63 nm at x=0 and x=0.3, respectively. This result implies that doping leads to more uniform grain distribution and enhanced grain refinement. Characterization via Vibrating Sample Magnetometer (VSM) revealed that the maximum saturation value, 0.79 emu/g, was attained when x = 0. This sample exhibits soft magnetic properties, as evidenced by its coercivity (Hc) value of < 1kOe. Results from the Vector Network Analyzer (VNA) indicate that the absorption capacity of La_(1-x)Ba_x/2Sr_x/2Mn_0.4Ti_0.6O₃ increases, with a maximum reflection loss value of -25.5 dB with 1.5 mm thickness. Consequently, La_(1-x)Ba_x/2Sr_x/2Mn_0.4Ti_0.6O₃ demonstrates potential as a microwave absorber material.