Vol. 56 No. 1 (2024)

Earthquake sources in Aceh have distinct characteristics. Understanding the seismic characteristics of each earthquake source is crucial for comprehending earthquake cycles and assessing seismic hazards. A key parameter in characterizing an earthquake source is the b-value, which indicates the relationship between the number of earthquakes and their magnitudes, influenced by the magnitude of completeness (Mc). The present study analyzed the seismic characteristics of two subduction zone segments and sixteen fault segments using the least squares method on selected earthquake data specific to…

Natural ingredients can have extraordinary potential as alternative medicines due to their accessibility and cost-effectiveness. Application of these ingredients should consider solubility and permeability, which determine the success of pharmaceutical characteristics formulation and biological activity indication. In this context, physical manipulation, specifically particle size reduction, is an effective strategy to address these issues. Previous research has explored active compounds in the stilbenoid group, found in the outer skin, hard shell, and endosperm of melinjo (Gnetum gnemon L.)…

TiO2NTAs is one of the most frequently used photoanodes. However, TiO2NTAs has a wide bandgap, so it is only active under UV light. Therefore, this study modified TiO2NTAs photoanode film to increase its efficiency. A simple method that successfully assists the Bi2S3 coating process on the surface of TiO2NTAs film is the Successive Ionic Layer Adsorption and Reaction (SILAR) method. In this research, modified Bi2S3 with TiO2NTAs was prepared using the SILAR method with variations of the number of synthesis cycles at 1, 2, 4, and 6. Based on the synthesis results, the number of deposition…

This research aimed to find out the provenance, paleo weathering, tectonic environment, sediment maturity, and economic value of beach sand deposits in two study areas. The study areas were located on south coast of Purworejo-Kebumen and Cilacap, respectively. Ten representative samples were collected by hand auger and dried to reduce their water content, manually separating the magnetite concentrate using a 300-gauss magnet. The mineral composition and fraction were observed using a binocular microscope. Major oxide and trace elements concentrations were measured using the X-ray fluorescence…

In this study, we explored a low-cost, green, and renewable approach utilizing biomass resources, i.e., coconut fronds, palm fronds, and rambutan stems, to rapidly synthesize graphene oxide via atmospheric plasma techniques. The plasma treatment, with argon gas as the plasma source and a power source of 960 W, lasted for 5 minutes. Graphene oxide (GO) was confirmed using SEM and TEM images with a C:O content ratio greater than 80% for all samples and the formation of graphene layers. The presence of a D-band and a G-band in Raman spectroscopy as well as O-H and C-O groups in the FTIR…