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Eksakta : Berkala Ilmiah Bidang MIPA
Published by Universitas Negeri Padang
ISSN : -     EISSN : 25497464     DOI : https://doi.org/10.24036/eksakta/
Core Subject : Science, Education, Agriculture, Social, Engineering,
Agriculture, Biological Sciences & Forestry Astronomy Biochemistry, Genetics & Molecular Biology Chemical Engineering, Chemistry & Bioengineering Chemistry Civil Engineering, Building, Construction & Architecture Computer Science & IT Energy Engineering Environmental Science Materials Science & Nanotechnology Mathematics Mechanical Engineering
Eksakta : Berkala Ilmiah Bidang MIPA (E-ISSN : 2549-7464) is an open access journal and peer-reviewed that publishes either original article or reviews. The journal is dedicated towards dissemination of knowledge related to the advancement in scientific research. The prestigious interdisciplinary editorial board reflects the diversity of subjects covered in this journal. Under the realm of science and technology, the coverage includes environmental science, pure and applied mathematics, agricultural research and engineering, biology, biotechnology, bioinformatics, Healthcare sciences (including clinical medicine, preventive medicine & public health), physics, biophysics, computer science, chemistry and bioengineering, to name a few. This Journal Is Published at 3 Month intervals on January-Marc, April-June, July-September and October-December
Arjuna Subject : Umum - Umum
Articles 402 Documents
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Spatial-Temporal Analysis of b-value Before and After the 2018 Lombok Earthquake Using OK1993 Based on Voronoi in the Bali-NTB Region Tata Dwi Hardi Yanti; Yudha Styawan; Rizki Wulandari
EKSAKTA: Berkala Ilmiah Bidang MIPA Vol. 27 No. 03 (2026): Eksakta : Berkala Ilmiah Bidang MIPA (E-ISSN : 2549-7464) In Progress
Publisher : Faculty of Mathematics and Natural Sciences (FMIPA), Universitas Negeri Padang, Indonesia

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.24036/eksakta/vol27-iss03/678

Abstract

This study is motivated by the tectonic complexity of the Bali-NTB region, which results in a heterogeneous seismic distribution and active stress dynamics. The objective is to analyze the spatiotemporal evolution of the b-value using the Ogata-Katsura maximum likelihood estimation (OK1993), combined with Voronoi tessellation as an adaptive spatial partition and the Bayesian Information Criterion (BIC) for ensemble model optimization. Spatial analysis prior to the 2018 event revealed a contradiction in the form of high b-value (>1.0) in Lombok. However, the spatiotemporal analysis successfully explains the condition by identifying a zone of low b-value (<1.0) that developed following the 2007 intermediate sized earthquake through the 2018 mainshock distinct from the 2004 local anomaly that did not progress into a major earthquake. This indicates that the persistence of low b-values is a key indicator of high stress accumulation. Following the 2018 earthquake, the high stress zone expanded across Lombok and West Nusa Tenggara (NTB). This study emphasizes the importance of evaluating statistical reliability, such as N(b) and Median Absolute Deviation (MAD), to avoid misinterpretations due to data limitations, thereby providing a more reliable framework for regional seismic hazard assessment.
Residual-Based Analysis of the Mismatch Between LoRa Channel Models and Field Measurements in Urban and Rural Environments Muhamad Bagus Fikril Alan; Pradini Puspitaningayu; Nurhayati Nurhayati; Muhammad &#039;Aamir Nashrullah; Nobuo Funabiki; Erwin Sutanto; Fahmi Fahmi
EKSAKTA: Berkala Ilmiah Bidang MIPA Vol. 27 No. 03 (2026): Eksakta : Berkala Ilmiah Bidang MIPA (E-ISSN : 2549-7464) In Progress
Publisher : Faculty of Mathematics and Natural Sciences (FMIPA), Universitas Negeri Padang, Indonesia

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.24036/eksakta/vol27-iss03/683

Abstract

This study investigates discrepancies between classical propagation models (Okumura-Hata, CI, FI) and LoRa field measurements in urban and rural environments. While rural areas exhibited linear path loss trends, urban scenarios showed distinct signal saturation, resulting in significant residuals even after model optimization. To address this, a residual-based analysis using Machine Learning (Linear Regression, Decision Tree, Random Forest) was proposed to map these systematic errors. The evaluation reveals that Random Forest (RF) significantly outperforms other algorithms, achieving an of 0.961 and an RMSE of 3.291 dB. These findings demonstrate that model mismatches follow deterministic patterns driven by environmental features rather than random noise. The study concludes that integrating ML-based residual compensation is essential for accurate radio planning in heterogeneous network deployments.
Influence of Species, Growing Site, and Postharvest Leaf Handling on the Yield and Chemical Composition of Cajuput Oil (Melaleuca spp.) from Seram Island, Indonesia Imanuel Berly Delvis Kapelle; Fensia Analda Souhoka; Nini Munirah Renur
EKSAKTA: Berkala Ilmiah Bidang MIPA Vol. 27 No. 03 (2026): Eksakta : Berkala Ilmiah Bidang MIPA (E-ISSN : 2549-7464) In Progress
Publisher : Faculty of Mathematics and Natural Sciences (FMIPA), Universitas Negeri Padang, Indonesia

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.24036/eksakta/vol27-iss03/687

Abstract

Cajuput (Melaleuca spp.) is a high-value non-timber forest product in Seram Island, Maluku. The quality of cajuput oil is primarily determined by its 1,8-cineole (eucalyptol) content, which is influenced by genetic, environmental, and raw material factors. This study analyzed the effects of species, growing location, and raw material condition on the yield and chemical composition of oil derived from Melaleuca leucadendra and Melaleuca cajuputi collected from Hatusua and Eti villages, using distillation and GC-MS analysis. The results showed that fresh leaves yielded higher amounts than dried leaves. The highest yield was obtained from M. leucadendra from Eti (1.022%), while the lowest yield was recorded from dried leaves (0.008%). M. leucadendra oil was dominated by eucalyptol (56.62–58.50%), whereas M. cajuputi was dominated by methyleugenol (81.61%) with a lower yield (0.1213%), reflecting differences in genetically controlled metabolic pathways. Environmental factors influenced yield and minor compounds without altering the dominant constituents. Overall, the quality and quantity of cajuput oil are determined by the interactions among genetic, environmental, and post-harvest factors. The use of fresh raw materials, appropriate species or chemotypes, and optimal growing locations is key to improving oil quality and ensuring consistent production.   
The Effect of Adding Ruku-Ruku Plant Essential Oil (Ocimumm tenuiflorum L.) as a Source of Antioxidants in Lip Balm Preparations Diana Sylvi; Tuty Anggraini; Anggun Anggun
EKSAKTA: Berkala Ilmiah Bidang MIPA Vol. 27 No. 03 (2026): Eksakta : Berkala Ilmiah Bidang MIPA (E-ISSN : 2549-7464) In Progress
Publisher : Faculty of Mathematics and Natural Sciences (FMIPA), Universitas Negeri Padang, Indonesia

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.24036/eksakta/vol27-iss03/686

Abstract

This study aims to evaluate the effect of adding ruku-ruku (Ocimum tenuiflorum) essential oil on the characteristics and antioxidant activity of lip balm, as well as to determine the best formulation. The research employed a Completely Randomized Design (CRD) with five treatments and three replications. The treatments consisted of different concentrations of essential oil: A (0%), B (1%), C (2%), D (3%), and E (4%). Data were analyzed using Analysis of Variance (ANOVA) followed by Duncan’s New Multiple Range Test (DMRT) at a 5% significance level. Evaluated parameters included homogeneity, applicability, irritation test, and organoleptic properties (color, aroma, and texture). The results showed that treatment B (1% essential oil) was the best formulation, with a pH value of 5.61, homogeneous texture without coarse particles, uniform and colorless application, and no irritation. It exhibited antioxidant activity of 53.83% and increased moisture by 21.56%. Organoleptic scores indicated good panelist preference for color (4.04), aroma (3.52), and texture (4.16). The main compounds identified were eugenol, limonene, and caryophyllene. Further studies are needed to assess shelf life stability.
A Comparative Study of Community Structure and Plankton Abundance in Seaweed Cultivation Areas in Puntondo, Takalar Regency Rafikah Amalia; Nita Rukminasari; Muh. Tauhid Umar; Irmawati Irmawati
EKSAKTA: Berkala Ilmiah Bidang MIPA Vol. 27 No. 03 (2026): Eksakta : Berkala Ilmiah Bidang MIPA (E-ISSN : 2549-7464) In Progress
Publisher : Faculty of Mathematics and Natural Sciences (FMIPA), Universitas Negeri Padang, Indonesia

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.24036/eksakta/vol27-iss03/691

Abstract

Healthy tropical coastal waters ideally have a diverse plankton community, which serves as an indicator of optimal ecological stability. Monitoring based on the analysis of plankton community structure is required as a means of detecting changes in the ecological conditions of the waters. Given the scarcity of ecological data in this region, this study aims to analyse the community structure and abundance of plankton in the waters off Puntondo as a basis for coastal ecosystem management. Sampling was carried out at three stations using purposive sampling with a No. 25 plankton net, and the data were analysed using ecological indices and multivariate analyses (nMDS, ANOSIM and SIMPER) via PRIMER version 5. The results showed that the phytoplankton consisted of 12 species dominated by Bacillariophyceae with an abundance of 476–520 ind/L, and the zooplankton consisted of 6 species dominated by Polychaeta with an abundance of 6090–6630 ind/L; there were no significant differences between stations for either group. Moderate diversity, high evenness and low dominance indicate that the plankton community is in a state of equilibrium, reflecting that the waters of Puntondo are still capable of sustaining the plankton ecosystem despite facing anthropogenic pressures that require ongoing monitoring.
Planting Media Composition Drives Vegetative Establishment and Biomass Accumulation of Grapevine Stem Cuttings under Tropical Nursery Conditions Wisnaningsih; Moh Haris Imron S Jaya
EKSAKTA: Berkala Ilmiah Bidang MIPA Vol. 27 No. 03 (2026): Eksakta : Berkala Ilmiah Bidang MIPA (E-ISSN : 2549-7464) In Progress
Publisher : Faculty of Mathematics and Natural Sciences (FMIPA), Universitas Negeri Padang, Indonesia

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.24036/eksakta/vol27-iss03/693

Abstract

The success of grapevine (Vitis vinifera L.) propagation through stem cuttings is strongly influenced by planting media quality during the nursery stage. Under tropical lowland conditions, unstable root-zone environments often reduce seedling vigor and biomass accumulation. Therefore, suitable manure-based media are needed to improve vegetative establishment and nursery efficiency. This study aimed to evaluate the effects of different manure-based planting media on vegetative growth and biomass accumulation of grapevine stem cuttings under tropical screen-house conditions in Bandar Lampung, Indonesia. The experiment was arranged in a randomized complete block design consisting of four treatments: M1 = sand + soil (1:1), M2 = sand + soil + cattle manure (1:1:1), M3 = sand + soil + goat manure (1:1:1), and M4 = sand + soil + chicken manure (1:1:1), with six replications. The results showed that the cattle manure-based medium consistently produced the best vegetative performance, increasing shoot length, leaf number, leaf area, fresh weight, and dry weight by 67.6%, 83.3%, 83.1%, 38.5%, and 40.4%, respectively, compared with the control treatment. Overall, cattle manure-based media provided the most favorable conditions for vegetative establishment and biomass accumulation of grapevine stem cuttings under tropical nursery conditions.  
Effects of Radiation on the Histology of the Tongue and Lip Mucosa in Rats : Preliminary Research Sagita Yudha; Aisyah Elliyanti; Eti Yerizel; Sukri Rahman
EKSAKTA: Berkala Ilmiah Bidang MIPA Vol. 27 No. 03 (2026): Eksakta : Berkala Ilmiah Bidang MIPA (E-ISSN : 2549-7464) In Progress
Publisher : Faculty of Mathematics and Natural Sciences (FMIPA), Universitas Negeri Padang, Indonesia

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.24036/eksakta/vol27-iss03/696

Abstract

The tongue and lip mucosa, as tissues with high cell proliferation rates, are highly susceptible to injury caused by ionizing radiation. This study aimed to evaluate histological changes in the tongue and lip mucosa of rats after exposure to ionizing radiation at various doses. Nine rats were used, each consisting of three rats, divided into a negative control group (K) and three treatment groups receiving radiation doses of 13 Gy (30 seconds of radiation), 15 Gy (66 seconds of radiation), and 17 Gy (110 seconds of radiation). Samples of tongue and lip mucosa tissue were harvested after 7 days and processed for histological examination using Hematoxylin and Eosin (HE) staining at 100x objective magnification. The results of this preliminary study showed that radiation at 13 Gy caused epithelial erosion, loss of filiform papillae, subepithelial bullae formation, and acute inflammatory cell infiltration on the tongue. At 15 Gy, more extensive ulceration with subepithelial edema was observed. At 17 Gy, total epithelial loss with massive subepithelial edema and vascular dilatation occurs. This preliminary study concludes that the tongue mucosa exhibits greater radiation sensitivity than the lip mucosa, with a dose-dependent progression of damage ranging from erosion to total epithelial loss.  
Data Acquisition System for Exothermic and Endothermic Reaction: A Novel Laboratory Approach in Chemistry Learning Siti Nuryani; Ijang Rohman; Miarti Khikmatun Nais; Gun GUn Gumilar; Muhamad Nurul Hana
EKSAKTA: Berkala Ilmiah Bidang MIPA Vol. 27 No. 03 (2026): Eksakta : Berkala Ilmiah Bidang MIPA (E-ISSN : 2549-7464) In Progress
Publisher : Faculty of Mathematics and Natural Sciences (FMIPA), Universitas Negeri Padang, Indonesia

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.24036/eksakta/vol27-iss03/697

Abstract

The determination of exothermic and endothermic reactions using conventional thermometers is often constrained by limitations in visualization and objectivity during practical activities. This study aims to investigate the performance of a DAS as an alternative for classroom practical work. The method involved characterizing thermal dynamics through a Design Science Research (DSR) approach using the MEDS evaluation framework. To record real-time temperature profiles, a thermistor sensor was integrated into the Mixer Mini and MGA as the DAS. Calcium carbide reaction and urea dissolution were utilized as the thermochemical systems. The analysis results show that the DAS: (1) is capable of detecting phenomena that go undetected using conventional methods; (2) exhibited strong baseline stability during the pre-reaction phase with a slope approaching zero and high reliability under homogeneous conditions, indicated by RSD values of 0.45% and 3.44% for urea dissolution and the calcium carbide-water reaction, respectively; and (3) showed stable internal consistency despite deviations from literature values caused by external factors. The novelty of this research lies in the operational efficiency of a self-contained measurement system that operates without the need for coding procedures. Consequently, the DAS provides a practical, objective, and scientifically valid solution to enhance data integrity in thermochemical analyses.
Synthesis of Nano alfa-Cellulose-Based Bioplastic from Empty Fruit Bunches of Palm Oil Benny Rio Fernandez; Rycce Sylviana Pratikha; Sari Farah Dina; Poltak Evencus Hutajulu; Gimelliya Saragih; Dafina Ariza; Indah Fitri Ramadhani; Yosef Boy Wijaya Sinaga
EKSAKTA: Berkala Ilmiah Bidang MIPA Vol. 27 No. 03 (2026): Eksakta : Berkala Ilmiah Bidang MIPA (E-ISSN : 2549-7464) In Progress
Publisher : Faculty of Mathematics and Natural Sciences (FMIPA), Universitas Negeri Padang, Indonesia

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.24036/eksakta/vol27-iss03/700

Abstract

Cellulose, as a renewable resource, has recently emerged as a primary focus for researchers aiming to develop sustainable biomaterials.  FTIR spectra show that there is no significant difference between them. Apparently, the significant absorption band of cellulose structure at 3300 cm-1 (O-H stretching), 2900 cm-1 (C-H stretching), and at 1022 cm-1 (OCH-O-CH2 cellulose framework). SEM images revealed that changing the surface morphology of the a-cellulose (fibril-shaped) to nano a-cellulose (rod-shaped) resulted in average fiber diameters of 3.07 µm and 2.80 µm, respectively. Particle size distribution of the suspended particles after acid and sonication treatment becomes 380.79 nm. Based on the DTA results, the obtained products have good thermal stability, which decomposes at a temperature 290 oC.　Furthermore, nano a-cellulose was used as a starting material to generate biodegradable plastic with the addition of silica as a filler and glycerin as a plasticizer. Mechanical tests of bioplastics, such as tensile strength, elongation, and modulus of elasticity, show that silica can improve the properties of bioplastics. Finally, the elongation properties of bioplastics meet the Indonesian National Standard (SNI) requirements; however, the tensile strength and modulus of elasticity values require further experiments.
Analysis of Fault Plane and Distribution of Coulomb Stress Changes of the Mw 7.8 Earthquake Southwest of Sumatra Gabriela Gabriela; Kelly Lasofia Br Girsang; Rizki Wulandari Wulandari; Yudha Styawan
EKSAKTA: Berkala Ilmiah Bidang MIPA Vol. 27 No. 03 (2026): Eksakta : Berkala Ilmiah Bidang MIPA (E-ISSN : 2549-7464) In Progress
Publisher : Faculty of Mathematics and Natural Sciences (FMIPA), Universitas Negeri Padang, Indonesia

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.24036/eksakta/vol27-iss03/701

Abstract

The Mw 7.8 earthquake that occurred southwest of Sumatra on March 2, 2016, at a depth of 24 km represents a major seismic event within the Sunda subduction zone, significantly influencing regional stress conditions. This study aims to analyze Coulomb stress changes (Δσc), examine stress distribution patterns, and evaluate the most representative fault plane controlling the earthquake source mechanism. The analysis was conducted using the Coulomb Stress Change method based on focal mechanism parameters and finite fault models obtained from the United States Geological Survey (USGS). The results indicate that Nodal Plane 1 (NP1) represents the true fault plane controlling the earthquake mechanism, with maximum stress increase of up to  0.1 bar and orientations from west–east to northwest–southeast. In contrast, Nodal Plane 2 (NP2) acts as a receiver fault, accommodating transferred stress from the main rupture, with similar stress magnitudes oriented north–south to west–east. The observed stress increases on both nodal planes highlight potential zones for aftershock occurrence. This study contributes to a better understanding of earthquake source mechanisms and stress redistribution patterns that may trigger subsequent seismic activity in the southwest  region of Sumatra..

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