Journal Of Natural Sciences And Mathematics Research
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Analysis of total phenolic content and antioxidant activity in Turi leaf extract (Sesbania grandiflora L.) with the use of different solvents
Full text linkThis study aims to evaluate the effect of solvent types on the total phenolic content and antioxidant activity of turi leaf extract (Sesbania grandiflora). The types of solvents used include ethanol, ethyl acetate, and n-hexane. The total phenolic content was measured using the Folin-Ciocalteu method with gallic acid as a standard, while the antioxidant activity was determined using the DPPH quenching method. The results showed that the highest total phenol content was obtained from ethyl acetate solvent (12.31 µg/mL), followed by ethanol (9 µg/mL) and n-hexane (6.34 µg/mL). However, antioxidant activity based on IC50 showed different results, where the extract with n-hexane solvent had the highest antioxidant activity (IC50 = 142.9 µg/mL) compared to ethyl acetate (IC50 = 245.47 µg/mL) and ethanol (IC50 = 271.8 µg/mL). These differences indicate that the type of solvent affects not only the amount but also the type of phenolic compounds and other bioactive compounds in the extract. This study highlights the importance of selecting an appropriate solvent to enhance the extraction efficiency of phenolic compounds and antioxidant potential
Efficient Numerical Method for Generating Closed Form Solution for Nonlinear Bratu Differential Equations
Full text linkThis study presents a numerical solution of the Bratu differential equations (BDE) using the Sumudu transform series decomposition technique (STSDT). The process combines the Adomian polynomials (AP), series expansion (SE), and Sumudu transform (ST), and it ultimately converges perfectly to the exact solution. Examining four test problems demonstrates that the strategy converges more effectively than the literature-based approach. Calculations were performed using Maple 2022 software
Mineralogical classification and impact simulation of the Punggur (H7-Melt Breccia) Meteorite, Indonesia
Full text linkMeteorite falls in Indonesia are rarely examined through systematic scientific analysis, resulting in limited documentation of fall events and incomplete classification of recovered specimens. The Punggur meteorite fall of 28 January 2021 reportedly produced at least five fragments. This study addresses that gap by analyzing two fragments (PM-01 and PM-02) to confirm their extraterrestrial origin and to characterize their physical, chemical, and mineralogical properties. Physical characterization involved measurements of density, magnetic susceptibility, and surface morphology. The chemical composition was determined using X-ray fluorescence (XRF), while microscopic imaging was employed to compare fusion-crust features with interior textures. A web-based meteoroid-impact modeling tool was further employed to estimate the atmospheric entry behavior and environmental effects of the fall. The result is that PM-01 has dimensions of 13 × 6.5 × 8 cm, a volume of 419 mL, a mass of 2200 g, and a density of 5.25 ± 0.26 g/cm³. PM-02 measures 25 × 23 × 16 cm, with a volume of 443 mL, a mass of 1820 g, and a density of 4.06 ± 0.06 g cm⁻³. Modeling results indicate that post-airburst fragments retained a residual velocity of approximately 16.2 km s⁻¹, while the airburst released an estimated 2.12 × 10¹⁰ J of energy (0.51 × 10⁻⁵ megatons). The shock wave reached observers 1.78 minutes after the event, accompanied by a maximum wind velocity of 0.0422 m s⁻¹ and sound levels near 25 dB—consistent with witness reports and the observed impact crater. Microscopic and XRF analyses reveal coarse-grained textures with high concentrations of Fe, Si, and Mg. PM-01 contains 23.55% Fe, 20.18% Si, and 12.48% Mg, whereas PM-02 contains 48.09% Fe, 25.06% Si, and 10.21% Mg. Thus, this finding indicates that the specimen’s mineralogy is dominated by olivine ((Mg, Fe)₂SiO₄), confirming that it aligns with the classification of an H7 melt breccia
Legendre Collocation approach for Integro-Differential equations
Full text linkThis study presents the application of the Legendre Collocation Method (LCM) for solving Integro-Differential Equations (IDEs), which model a range of scientific and engineering problems.IDEs, involving both differential and integral terms, often require numerical methods for their solutions due to the complexity of obtaining exact solutions. The proposed approach transforms IDEs into systems of linear algebraic equations using shifted Legendre polynomials. By collocating the resulting equations, approximate solutions are efficiently computed. The accuracy of the method is validated through several numerical examples, including Volterra and Fredholm types of IDEs, and the results are compared with known exact solutions. The effectiveness and robustness of LCM are demonstrated through high-order approximations. The theoretical uniqueness of the method is established using relevant theorems, including the Banach Contraction Principle. Overall, the LCM provides a reliable and efficient technique for solving a wide class of IDEs with high accuracy.
Dynamic program for selecting syari’ah share for maximum profit
Full text linkThe right investment can increase a person's income by placing a number of funds in an investment instrument. One of the investment instruments is investing in the capital market by buying a number of stocks with good fundamentals. The selection of syari’ah shares is the right choice for the Indonesian people, most of whom are Muslim. The method used to select Islamic stocks in this study is dynamic programming. Simulations carried out with dynamic program algorithms produce selected syari’ah stocks, namely ACES, ICBP, SMGR and ANTM in order to get the maximum profit. Among the five shares, the one that provided the greatest return was ANTAM shares. This was proven in 2025 when ANTAM's share price rose by 22% even though the Indonesian economy was sluggish. ANTAM shares are given priority as shares that an investor must own
Analysis of Population, Poverty, Unemployment Rate, and Gini Ratio on Human Development Index in Bangka Belitung
Full text linkThe Human Development Index (HDI) is a measure that evaluates human development achievements based on fundamental quality-of-life components that can influence individual productivity levels. This study aims to analyze the impact of Population Size, Percentage of Poor Population, Open Unemployment Rate (TPT), and Gini Ratio on the Human Development Index (HDI) in the Bangka Belitung Islands Province from 2018 to 2023. The panel data regression method was employed, combining time series and cross-sectional data to provide more accurate information. The findings reveal that the HDI of the Bangka Belitung Islands Province has increased yearly, though it remains below the national average. The selected model was the Fixed Effect Model (FEM) based on the results of the Chow and Hausman tests. Analysis indicates that Population Size has a positive and significant effect on HDI, while the Percentage of Poor Population has a negative and not significant effect. Additionally, the Open Unemployment Rate (TPT) has a positive and significant effect on HDI, whereas the Gini Ratio has a negative and significant effect. Simultaneously, the four independent variables contributed 95.44% to HDI. These findings are expected to inform government efforts to improve human development quality, such as poverty alleviation, and highlight the need for attention to population management in balancing employment opportunities in the region and the government should work to reduce the unemployment rate through policies that focus on job creation, increasing workforce competitiveness, and addressing inequality, as reflected by the Gini ratio. This can be achieved by expanding equitable access to education and healthcare
American index exchange movement against IDX stochastic
Full text linkA giant warehouse full of countless opportunities forms the foundation of this study, which aims to conduct stochastic modeling of the impact of the movement of the American stock index on the IDX (Indonesia Stock Exchange). This research discusses and emphasizes how the movement of the American stock index affects changes in the IDX over a certain period of time using a quantitative approach. The study employs a Hidden Markov Model (HMM) to identify latent market states. It utilizes the Viterbi method to determine the most probable sequence of state transitions based on the observed data. The model was trained using historical movements of the NASDAQ, NYSE, and DOW JONES indices, facilitating the discovery of significant trends in IDX changes. The research results show a trend in the movement of the IDX based on the movement of the American indices NASDAQ, NYSE, and DOW JONES, as follows: Bullish, bearish, bullish, bearish when NASDAQ is observed at 1, 2, 5, 6, and 8; NYSE is observed at 1, 3, 9, 11, and 15; and DOW JONES is observed at 1, 3, 4, 7, 9, 10, 11, 12, 13, 15, and 16. Bearish, bullish, bearish, bullish when NASDAQ is observed at 3, 9, 11, and 15; NYSE is observed at 2, 5, 6, and 8; and DOW JONES is observed at 2, 5, 6, 8, and 14. Bearish, bullish, bearish, bearish when NASDAQ is observed at 4, 12, and 16. Bullish, bearish, bullish, bullish when the NYSE is observed at 4 and 12. Bullish, bearish, bearish, bullish when NASDAQ is observed at seven and when NYSE is observed at 10. Bearish, bullish, bullish, bearish when NASDAQ is observed at 10. Bearish, bearish, bullish, bearish when NASDAQ is observed at 13 and 14. Bullish, bullish, bearish, and bullish when the NYSE is observed at 13, 14, and 16. The analysis indicates that IDX trends generally fluctuate in line with major U.S. indices (NASDAQ, NYSE, DOW JONES). Notably, specific observations 4, 12, 13, 14, 16 reveal a stronger correlation: a bearish NASDAQ movement tends to align with a bearish IDX stochastic, whereas a bearish NYSE movement is more likely to trigger a bullish response in the IDX
Risk analysis of air quality for parameters NO2, SO2, NH3, and Ox from the area around fertilizer industries in Indonesia
Full text linkIndustrial zones with intensive human activities often experience air-quality degradation, particularly in areas surrounding fertilizer production facilities. This study analyzes the concentrations of nitrogen dioxide (NO₂), sulfur dioxide (SO₂), ammonia (NH₃), and oxidants (Ox) in the ambient air around fertilizer industries in Indonesia and evaluates their potential non-carcinogenic health risks. Air sampling was conducted using an InScienPro US-1012 impinger equipped with selective absorbent solutions. Pollutant concentrations were quantified using UV-Vis spectrophotometry based on the Griess–Saltzman method for NO₂, the pararosaniline method for SO₂, the indophenol method for NH₃, and the neutral buffer potassium iodide method for Ox. Concentrations were compared with national ambient air-quality standards. To strengthen the assessment, a quantitative health-risk evaluation was incorporated using the Hazard Quotient (HQ) and Hazard Index (HI), allowing for the interpretation of long-term exposure impacts. Results show that most pollutant concentrations were below regulatory limits; however, SO₂ levels at one sampling point and NH₃ levels near the production zone were elevated. The HQ–HI analysis revealed that SO₂ at the office-area sampling point (HQ = 0.794) and NH₃ inside the processing plant (HQ = 2.238) were the dominant contributors to cumulative exposure, with HI values exceeding 1 at both locations. These findings indicate potential non-carcinogenic risks for individuals chronically exposed in areas closest to emission sources. Overall, this study highlights the importance of continuous monitoring and risk-based evaluation to identify localised hotspots, inform mitigation strategies, and enhance emission control practices in fertiliser-industrial environments
Potential of local material SiO2 water Hyacinth for semiconductor materials
Full text linkThis study aims to examine the potential of local SiO₂ material synthesized from water hyacinth biomass waste as a candidate for semiconductor materials. Synthesis was carried out through a calcination process at temperatures above 600 °C to remove cellulose, lignin, and other impurities. Material characterization was carried out using UV-Vis spectroscopy, X-ray Diffraction (XRD), and Raman Spectroscopy. The results of UV-Vis spectroscopy showed that the water hyacinth derived SiO₂ exhibited an unusually reduced optical band gap of approximately 2.3 eV, likely influenced by impurity phases.. XRD tests indicated the presence of two crystal phases, namely the trigonal structure of SiO₂ and the monoclinic structure of the CaH₁₂O₁₇Si₂U₂ compound. Raman analysis confirmed the presence of functional groups such as Si, amorphous SiO2, CH₂/CH₃ and vibration signals from irregular sp² carbon. This combination of structures is thought to cause a lower band gap value compared to pure SiO₂. This finding indicates that SiO₂ from water hyacinth has potential as an intermediate semiconductor material, although further purification is still needed to increase the purity of the SiO₂ phase
Evaluating surface water and groundwater quality parameters in the Karst Mining Zone, Gunungkidul for environmental risk mitigation
Full text linkThis study aims to characterize the physical, chemical, and microbiological water parameters of the Oya River (Bleberan Playen) and groundwater in the CV Kusuma Arga monitoring well, located in the white stone mining zone, Ponjong District, Gunungkidul Regency, Special Region of Yogyakarta, Indonesia. The importance of this research is driven by the lack of comprehensive water quality data in active karst mining areas and the potential environmental and health risks associated with contamination. Parameters tested included temperature, electrical conductivity (EC), total dissolved solids (TDS), turbidity, pH, nitrite, ammonia, chloride, sulfate, detergents, dissolved iron, dissolved lead, dissolved copper, dissolved cadmium, dissolved manganese, dissolved nickel, total coliform, and fecal coliform. Testing methods referred to the Indonesian National Standard (SNI) and Standard Methods, including the use of atomic absorption spectrophotometry (AAS) for heavy metal analysis and the membrane filter method for microbiology. The test results showed that most physical and chemical water parameters from both sources met the relevant quality standards. For example, the well water temperature of 27°C and well water pH of 6.9 were both declared to be by standards. However, analysis showed lead concentrations (0.1 mg/l in the river) and cadmium (0.010 mg/l in the river) exceeding World Health Organization (WHO) recommendations for drinking water, although initially categorized as "appropriate". Furthermore, total coliform (3000-5000 MPN/100ml) and fecal coliform (4000-4500 MPN/100ml) concentrations in both samples were very high, clearly indicating a health-risking fecal contamination, despite also being declared "appropriate" in the report. The role of Environmental Engineering science is crucial in sample collection, laboratory analysis, and interpretation of this data. This study contributes to the understanding of water quality in areas affected by mining activities and emphasizes the need for further evaluation for sustainable environmental management