Authors:Abdi Jihad, Vrieslend Haris Banyunegoro, muksin umar, marwan ramli, Syamsidik Syamsidik, yunita idris, Andi Azhar Rusdin Pages: 1 - 17 Abstract: 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 each segment. The analysis revealed that the b-value ranged from 0.5 to 0.6 in the subduction zone segments and from 0.3 to 1.0 in the fault segments. These variances in b‑value reflect the different seismic characteristics of the earthquake sources that shape the tectonic settings in Aceh. A lower b-value signifies an elastic zone capable of holding higher stress levels, whereas a higher b-value indicates a brittle zone that can only withstand lower stress levels. PubDate: 2024-07-31 DOI: 10.5614/j.math.fund.sci.2024.56.1.1 Issue No:Vol. 56, No. 1 (2024)
Authors:Marlina Indriastuti, I Ketut Adnyana, Rika Hartati, Heni Rachmawati Pages: 18 - 29 Abstract: 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.) seeds, functioning as antioxidant. Based on the potential as antioxidant, stilbenoid compounds, including resveratrol, contained in melinjo seed hardshell have shown significant pharmacological effects. Therefore, this research aimed to investigate the potential of melinjo seed hardshell extract as a natural antioxidant alternative by modifying the particle size through a grinding process to obtain nanoparticles. The analysis was carried out using ball milling to enhance the solubility of melinjo seed hardshell extract by increasing the saturated solubility and surface area of the particles. The results showed that the total phenol content and the antioxidant power increased significantly (p < 0.05) after ball milling. Melinjo seed hardshell nanoextract is reported herein as a promising source of natural antioxidant from local Indonesian plants. PubDate: 2024-08-08 DOI: 10.5614/j.math.fund.sci.2024.56.1.2 Issue No:Vol. 56, No. 1 (2024)
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