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Jurnal Ilmiah Sains
Published by Universitas Sam Ratulangi
ISSN : 14123770     EISSN : 25409840     DOI : https://doi.org/10.35799/jis.v22i2.40961
Core Subject : Science, Education, Agriculture,
Agriculture, Biological Sciences & Forestry Biochemistry, Genetics & Molecular Biology Chemistry Computer Science & IT Mathematics Physics
Jurnal Ilmiah Sains (Journal of Scientific Sciences) is the Journals Published by Faculty of Mathematics and Natural Sciences, Sam Ratulangi University. Jurnal Ilmiah Sains Published Twice a Year, i.e April and October. Jurnal Ilmiah Sains  welcomes full research articles in the area of Mathematics and Natural Sciences from the following subject areas: Mathematics Statistics Computer Science Physics Chemistry Biology
Arjuna Subject : Umum - Umum
Articles 353 Documents
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Hydrogeophysical Characterization of Volcanic Aquifers Using Integrated Resistivity and Induced Polarization in Mount Tumpa, Manado As'ari As'ari; Seni Herlina J. Tongkukut; Mahendra Kusuma Nugraha
Jurnal Ilmiah Sains Volume 26 Issue 1, April 2026
Publisher : Sam Ratulangi University, Manado, Indonesia

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.35799/jis.v26i1.65145

Abstract

This study investigates the aquifer system in the Mount Tumpa area, North Sulawesi, Indonesia, using integrated electrical resistivity and induced polarization (IP) methods. Data were acquired with a dipole–dipole array, enabling high lateral resolution of subsurface heterogeneity. Resistivity inversion was used to delineate aquifer geometry, while IP data were analyzed to identify zones of enhanced electrochemical polarization related to lithological and mineralogical variations. Aquifer zones are characterized by low resistivity values (< 9.17 Ωm). On Line 1, an aquifer is identified at 100–130 m and depths of 15–25 m; on Line 2, at 215–230 m and depths of 10–20 m. On Line 3, three distinct aquifer units are resolved: (1) 150–175 m at depths ≥ 75 m, (2) 220–235 m at 30–40 m, and (3) 285–305 m at 35–45 m. These findings indicate a multi-layered groundwater system with variable depth distribution. Chargeability responses are high on Lines 1 and 3 and moderate on Line 2, suggesting the presence of polarizable materials such as volcanic clay, iron oxides, and organic-rich layers. These materials may influence groundwater geochemical behavior through adsorption and redox processes; however, IP responses do not directly indicate groundwater quality in the absence of hydrochemical data. The subsurface is interpreted as a layered volcanic aquifer system, where groundwater is primarily hosted in permeable lapilli and volcanic ash deposits overlying compact lava, with additional storage in fractured lava zones. The identified aquifers are interpreted as shallow to intermediate systems based on geophysical evidence, although further hydrogeological validation is required. Keywords: resistivity method; induced polarization; chargeability; Mount Tumpa; aquifer characterization
Frequency-Dependent Magnetic Susceptibility of Sediments of Lake Tondano, Minahasa, North Sulawesi Vistarani Arini Tiwow; Meytij Jeanne Rampe; Ishak Pawarangan; Muhammad Arsyad; Sayenne Givenshe Pungus; Gita Gratia Patris Nangka; Igreya Mitchell Kumendong; Oksan Prasetio Mundiahi
Jurnal Ilmiah Sains Volume 26 Issue 1, April 2026
Publisher : Sam Ratulangi University, Manado, Indonesia

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.35799/jis.v26i1.65698

Abstract

A study has been conducted on frequency-dependent magnetic susceptibility in sediments of Lake Tondano, Minahasa, North Sulawesi. This study aims to analyze the types of minerals, grain sizes, and magnetic domains in sediment samples of Lake Tondano. The method used is the rock magnetism method, specifically the magnetic susceptibility parameters. Magnetic susceptibility measurements used a Bartington susceptibility meter that works at two frequencies, namely 470 Hz and 4700 Hz. The results obtained are sediment samples are indicated to contain ferrimagnetic minerals. The grain size distribution in sediment samples is predominantly fine <0.03 µm. The frequency-dependent magnetic susceptibility value χFD% is dominantly more than 2%, indicating the magnetic domain in sediment samples of Lake Tondano are a mixture of superparamagnetic (SP) and single-stable-domain (SSD). Keywords: Magnetic domains; magnetic minerals; lake sediments; magnetic susceptibility; magnetic grain size
Sentiment Analysis of Healthcare Services at RSUD Soe Using Machine Learning and Latent Dirichlet Allocation Saekoko, Agatha Marilin; Purnomo, Hindriyanto Dwi; Nataliani, Yessica
Jurnal Ilmiah Sains Volume 26 Issue 1, April 2026
Publisher : Sam Ratulangi University, Manado, Indonesia

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.35799/jis.v26i1.67193

Abstract

Healthcare services constitute a crucial aspect in improving public well-being. Every individual has the right to receive healthcare services that are of high quality, safe, efficient, and affordable. This study aims to identify and analyze public perceptions and sentiments toward healthcare services at RSUD Soe, as well as to evaluate the performance of several machine learning methods in classifying such sentiments. The data were collected from 278 respondents through a Likert-scale questionnaire that represents perceptions and levels of satisfaction regarding various service aspects. Sentiment analysis was conducted using four machine learning algorithms, namely Naïve Bayes, C4.5, Random Forest, and Support Vector Machine. The results indicate that Naïve Bayes achieved the highest accuracy of 82.14 percent, followed by SVM at 80 percent, Random Forest at 79 percent, and C4.5 at 73.21 percent. This study also applied the Latent Dirichlet Allocation (LDA) method to identify the main themes within public feedback. LDA generated twelve topics reflecting key issues such as waiting time, availability of medical personnel, facility cleanliness, and the attitudes of healthcare staff. The majority of comments exhibited positive sentiment, particularly concerning staff friendliness and service quality. These findings were used to formulate improvement recommendations, including enhancing service quality, increasing the number of medical personnel, and optimizing facilities. This research demonstrates that a data-driven quantitative approach is effective in evaluating healthcare service quality and supporting more targeted decision-making. The results are expected to assist RSUD Soe in continuously and effectively improving service quality.

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