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Justek : Jurnal Sains Dan Teknologi
Published by Universitas Muhammadiyah Mataram
ISSN : 26205475     EISSN : 26205475     DOI : -
Core Subject : Science, Education, Engineering,
Computer Science & IT Control & Systems Engineering Education Mathematics
Arjuna Subject : -
Articles 289 Documents
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Life Cycle Assessment (LCA) of Biodiesel Production from Coconut Pulp Using In-Situ Transesterification with Microwave Energy Daya Wulandari; Riztamala Diana; Godlove Elioth Kiswaga; Leila Utarina; Devina Sanchia Samosir; Marisa Tri Octavia
Justek : Jurnal Sains dan Teknologi Vol 9, No 2 (2026): June
Publisher : Unversitas Muhammadiyah Mataram

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.31764/justek.v9i2.38010

Abstract

Coconut pulps are solid waste from coconut processing that has had its coconut milk extracted, with a remaining oil content of around 12.2–15.9%. The processing of coconut pulp is not yet optimal, and this waste has the potential to be utilized as renewable energy in the form of biodiesel. Biodiesel is produced through an in-situ transesterification process assisted by microwave energy. This study aims to identify the potential environmental impacts of biodiesel production from coconut pulp as fuel. A Life Cycle Assessment (LCA) was conducted using the cradle-to-gate approach with the SimaPro ver. 9.4.0.3 data processing application and a database similar to the eco-invent database. The environmental impact assessment was analyzed using the EF 3.0 Method (adapted) V1.03 / EF 3.0 normalization and weighting set. The results show that among the stages of the biodiesel production process, the transportation of raw materials and supporting materials has the greatest impact on climate change compared to other stages. The transportation stage contributed 78.19 kg CO₂-eq out of a total of 204.35 kg CO₂-eq in the climate change category and dominated energy resource use at 1108.14 MJ out of a total of 1742.17 MJ. In addition, the preparation stage also contributed significantly to climate change, with emissions reaching 56.21 kg CO₂-eq. The large contribution from the transportation stage was mainly caused by exhaust gas emissions from vehicles used to transport raw materials and supporting materials. Based on the LCA results, environmental performance improvements or continuous improvements that can be implemented include optimizing logistics, regulating fuel use, selecting the nearest sources of raw materials, and improving energy efficiency during the preparation stage to support more sustainable biodiesel production from coconut pulp.
Integration of Geographic Information Systems in the Economic Valuation Analysis of Food Crops in Bleberan Village Muhammad Miftahurridlo; Zulfajri Zulfajri; Nur Hasanah; Darliandri Darliandri; Rohil Al Azizah
Justek : Jurnal Sains dan Teknologi Vol 9, No 2 (2026): June
Publisher : Unversitas Muhammadiyah Mataram

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.31764/justek.v9i2.39495

Abstract

The agricultural sector is a mainstay of the Indonesian economy, yet it faces serious challenges in the form of a nationwide decline in cultivated land area. This study aims to examine the state of food crop agriculture, identify the benefits derived by the community, and analyze the Total Economic Value (TEV) of agricultural activities in Bleberan Village, Playen Subdistrict, Gunungkidul Regency. The research method used is quantitative descriptive with an economic valuation approach. Data collection was conducted through observation, documentation, and interviews with 100 farmer respondents selected using the Slovin formula. Data analysis includes the calculation of direct utility value, indirect utility value, option value, and existence value. The results of the study indicate that agricultural activities in Bleberan Village are divided into three main phases: pre-planting, planting, and post-harvest, with corn as the flagship commodity due to its adaptation to dry land. The Total Economic Value (TEV) of food crop agricultural activities in Bleberan Village reached Rp 2,584,508,776. This value consists of direct benefits of Rp 1,493,057,500, indirect benefits of Rp 1,089,829,596 (including oxygen-producing and carbon-absorbing functions), choice value of Rp 468,840, and existence value of Rp 1,152,840. These findings confirm that the economic benefits of agriculture extend far beyond the mere market value of commodities, encompassing ecosystem services and existential values that are crucial to the sustainability of the region.
Is it Permissible to Drill Groundwater for Business on Gili Trawangan Islands Swahip Swahip; Ahmad Fathoni; Kusnadi Kusnadi; I Wayan Sudiyanto
Justek : Jurnal Sains dan Teknologi Vol 9, No 2 (2026): June
Publisher : Unversitas Muhammadiyah Mataram

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.31764/justek.v9i2.39618

Abstract

The pros and cons of groundwater drilling in the main tourism area of Gili Trawangan, North Lombok Regency have caused the government to revoke the groundwater extraction permits of several companies in 2022. Then there was a freshwater crisis in Gili until now in 2025. The purpose of this study was to analyze the potential of groundwater and the alleged impact of seawater intrusion in Gili as well as recommendations for groundwater business licensing policies on the island of Gili. The research method used geohydrological analysis and water balance analysis. The results showed that there are 5 (five) rock layers in Gili, namely coastal alluvial, reef, fine sand, coarse sand/reef and fine sand. Hydrogeological Borehole Log and Recovery for the aquifer layer are free or Unconfined Aquifer. In the pumping test with a capacity of 61.6 and 16.6 liters / second for 2 x 24 hours resulted in a decrease in the groundwater level of 0.5 meters and a relapse rate of only 2 minutes causing the groundwater level to return to normal height. Observations on the water quality revealed an alkaline pH and low salinity of 5 grams per liter, necessitating distillation techniques to obtain fresh water.
A Comparative Study on the Effectiveness of Iron (Fe) Adsorption from Acid Mine Drainage Using Single and Composite Adsorbents Mycelia Paradise; Yudha Agung Pratama; Faisol Mukarrom; Triyono Triyono; Akhmad Zamroni
Justek : Jurnal Sains dan Teknologi Vol 9, No 2 (2026): June
Publisher : Unversitas Muhammadiyah Mataram

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.31764/justek.v9i2.38233

Abstract

Acid mine drainage (AMD) is mining waste that has high acidity and dissolved metal content, especially iron (Fe), which has the potential to pollute the aquatic environment. This research aimed to evaluate the performance of coconut shell activated charcoal and local composite-based adsorbents (active charcoal–clay–zeolite) in reducing Fe concentrations in AMD. The research was conducted using two types of samples: real AMD collected from the mine site and synthetic AMD prepared in the laboratory using a FeSO₄·7H₂O solution. The composite adsorbent was tested using real AMD (baseline pH 2.6; Fe 42.75 ppm), while activated charcoal was tested on synthetic AMD (baseline pH 4.7; Fe 40.37 ppm). The main variables observed were dissolved Fe concentration and pH changes at various contact time variations. Analysis of Fe concentrations was carried out using AAS, while pH was measured directly with a pH meter. Adsorbent characterization was performed with BET to identify the specific surface area of the adsorbents. Results showed that activated charcoal was able to increase pH to 8.6 and decrease Fe to 0.04 ppm (99.9% efficiency). The primary mechanism of Fe reduction is dominated by Fe(OH)₃ precipitation, which occurs due to an increased pH. In contrast, the composite produced a final pH of 4.3 but still decreased Fe to 0.52 ppm (98.8% efficiency). BET analysis showed that although activated charcoal had a greater surface area, the composite maintained better pore stability after adsorption. The integration of the two has the potential to enhance the adsorption effectiveness and stability in the field for the remediation of acid mine drainage.
Application of Mosquito Net Control in a New Dynamics of Dengue Nilwan Andiraja
Justek : Jurnal Sains dan Teknologi Vol 9, No 2 (2026): June
Publisher : Unversitas Muhammadiyah Mataram

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.31764/justek.v9i2.39546

Abstract

This study discusses the application of mosquito net control in the SIR-UV model for the spread of dengue fever. The study has a specific objective to analyze the effectiveness of mosquito net control on the vulnerable human population to reduce the number of people infected with dengue fever. This research begins by forming a new SIR-UV mathematical model (state equation) with mosquito net control in the class of vulnerable human population and creating a new objective function to minimize the population of humans infected with dengue fever. Next, using Pontryagin's principle, the Hamiltonian function was formed. From the Hamiltonian function, the costate equation and the optimal control for the use of mosquito nets were obtained. The next step is to change the state equation and the costate equation using the 4th order Runge-Kutta method. Then a numerical simulation is performed, with the forward sweep method determining the solution to the state equation, and the backward sweep method for solving the costate equation. Numerical simulations will be conducted to observe the effects of control on the class of human population infected. The numerical simulations will use some data from previous research so that the simulation results can be compared with the previous research findings. The simulation results show that the use of mosquito nets on the vulnerable human population class can reduce the population of humans infected with dengue fever, where from the initial time of day 0, the graph of infected humans immediately drops below 20 days and continues to approach zero until day 100. It has same results for mosquitoes infected, which decreased immediately from the start continued to approach zero until days 100. In contrast, without control, there is a spike in the number of infected humans at the beginning and will approach zero by day 80 and it took until day 60 for the mosquitoes infected population with dengue virus to approach 0. Therefore, the use of mosquito nets on the vulnerable human population can reduce the number of humans infected with dengue fever and, of course, contribute to minimizing the spread of dengue fever.
Effectiveness Ethanol Extract of Tinospora crispa L, Cymbopogon citratus, Alpinia purpurata K Schum, and Alpinia galanga L in Lowering Mouse Cholesterol Levels Khoirul Ngibad; Dane Prastio; Evinia Eka Novem; Ragil Tri Sutrisno; Agustina Wulandari; Gaby Ayu Patricia; Cicik Wijayanti
Justek : Jurnal Sains dan Teknologi Vol 9, No 2 (2026): June
Publisher : Unversitas Muhammadiyah Mataram

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.31764/justek.v9i2.38814

Abstract

Hypercholesterolemia is a lipid metabolism disorder that increases the risk of cardiovascular disease. Although statins are effective, long-term use may cause side effects, prompting the exploration of natural alternatives that contain bioactive flavonoids, phenolics, and terpenoids with hypocholesterolemic activity. This study aimed to evaluate the cholesterol-lowering effects of ethanol extracts of Brotowali (Tinospora crispa L.), Lemongrass Stem (Cymbopogon citratus), Red Galangal (Alpinia purpurata K. Schum.), and White Galangal (Alpinia galanga L.) in hypercholesterolemia-induced male mice. A true experimental study was conducted using 36 male mice divided into six groups: Negative Control (I), Positive Control (II), Drug Control (Simvastatin) (III), and three extract groups (IV–VI) receiving doses of 14, 28, and 56 mg/20 g BW. After a seven-day adaptation period, the animals were administered propylthiouracil for 14 days to induce hypercholesterolemia, which was confirmed by blood cholesterol measurement on Day 15. Subsequently, simvastatin or the extracts were administered for three days, and cholesterol levels were measured on Day 18 using a spectrophotometric method. The results showed that all extracts reduced cholesterol levels compared to the Positive Control (194.65 ± 8.26 mg/dL), but were less effective than simvastatin (103.15 ± 15.54 mg/dL). Brotowali reduced levels to 140.90 ± 10.10 mg/dL; Lemongrass Stem to 143.47 ± 21.65 mg/dL. Red Galangal reached 138.79 ± 10.69 mg/dL and White Galangal 139.03 ± 16.53 mg/dL at the highest dose (56 mg/20 g BW). In conclusion, the four ethanol extracts showed potential as natural antihypercholesterolemic agents, with Red and White Galangal demonstrating the greatest cholesterol-lowering effects at a dose of 56 mg/20 g BW, although their efficacy remained lower than simvastatin.
Construction and Validation of the Artificial Intelligence Disclaimer Literacy Scale Instrument (AI-DLS) Abdul Rahman; Azlena Vira Safitri; Lazaro Kumala Dewi
Justek : Jurnal Sains dan Teknologi Vol 9, No 2 (2026): June
Publisher : Unversitas Muhammadiyah Mataram

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.31764/justek.v9i2.37803

Abstract

The use of Generative Artificial Intelligence (GenAI) in higher education poses epistemic risks, including information hallucinations, limited accuracy, and content bias. Although AI developers include disclaimers as a risk mitigation measure, the effectiveness of this mechanism is often hampered by the phenomenon of warning fatigue, so it does not always encourage user evaluative behavior. This study aims to develop and validate the Artificial Intelligence Disclaimer Literacy Scale as a psychometric instrument to measure students' awareness, understanding, attitudes, and critical evaluation of AI disclaimers. The study employed a quantitative psychometric development design divided into five stages: literature review, indicator formulation, instrument item development, empirical testing, and statistical validation. The instrument was tested on 165 students at the Faculty of Teacher Training and Education. Data analysis included item validity testing using corrected item–total correlation, reliability testing using Cronbach's Alpha, and Exploratory Factor Analysis (EFA) using the Principal Component Analysis (PCA) method with Varimax rotation to test construct validity. The results showed that the AI-DLS instrument, consisting of 30 statement items, was proven valid and reliable. All items had a correlation value ≥ 0.30, with excellent reliability across all four dimensions (Cronbach's Alpha = 0.828 - 0.937). The EFA results showed a Kaiser–Meyer–Olkin (KMO) value of 0.932 and a factor structure capable of explaining 66.89% of the total variance. These findings indicate that the AI-DLS has strong psychometric qualities and is suitable for use as a diagnostic instrument to map students' epistemic readiness to interact with Artificial Intelligence systems critically and responsibly.
Proposed Warehouse Layout Improvement for Optimizing Travel Distance and Material Handling Costs Using the ABC Method at PT X Agi Agus Setiawan Sufyan; Yayan Mulyana; Ilham Eka Santang; Afriani Kusumadewi
Justek : Jurnal Sains dan Teknologi Vol 9, No 2 (2026): June
Publisher : Unversitas Muhammadiyah Mataram

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.31764/justek.v9i2.37750

Abstract

The research employed a quantitative descriptive approach using warehouse operational data, including picking frequency, rack coordinates, and material movement information. Inventory items were classified into three categories—Class A (fast-moving), Class B (medium-moving), and Class C (slow-moving)—based on usage frequency. Subsequently, warehouse rack positions were rearranged according to ABC priorities, followed by recalculation of travel distances and material handling costs. The findings indicate that the proposed warehouse layout significantly improves operational efficiency for frequently moved products. The total travel distance for Class A items decreased from 1,662 meters to 1,272 meters, representing a reduction of 23%, while Class B items decreased from 807 meters to 771 meters, equivalent to a 4% reduction. Consequently, material handling costs for Class A and Class B movements also decreased proportionally. Although Class C travel distance increased from 279 meters to 705 meters, this change is considered acceptable because slow-moving items contribute minimally to warehouse movement frequency. The study concludes that integrating ABC classification with Rectilinear distance measurement effectively optimizes warehouse layout by reducing travel distance and material handling costs while improving storage efficiency for high-frequency inventory.
A Business Intelligence Approach to Analysing Youth Unemployment Trends and Provincial Disparities in Indonesia (2021–2025) Zuli Maulidati; Arsyi Aisyah Salwa; Amelia Putri Kurniahayu; Ruli Utami; Anwar Sodik
Justek : Jurnal Sains dan Teknologi Vol 9, No 2 (2026): June
Publisher : Unversitas Muhammadiyah Mataram

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.31764/justek.v9i2.38912

Abstract

Youth unemployment continues to be a significant challenge in Indonesia, reflecting structural constraints in labour market absorption and regional disparities. This study aims to analyse youth unemployment trends and provincial differences using a Business Intelligence (BI) dashboard approach based on data from the National Labour Force Survey (SAKERNAS) covering 38 provinces during the period 2021–2025. The analysis integrates trend observation and comparative benchmarking to evaluate temporal dynamics and provincial performance relative to the national average. The results indicate that youth unemployment exhibits fluctuating patterns without sustained improvement. At the provincial level, significant disparities are observed, with several provinces such as Maluku, Banten, Aceh, and Jawa Barat consistently recording higher unemployment rates compared to the national benchmark and there is a total of 22 provinces identified as high-risk regions. From this study, the implementation of the BI dashboard enables to integrate the multiple analytical perspectives into a single interface, facilitating clearer interpretation of trends, regional differences, and priority areas. This study contributes by demonstrating how BI-based analytical approaches can enhance the interpretation of labour market data and support data-driven decision-making. The findings highlight the importance of region-specific strategies in addressing youth unemployment, as national-level policies may not adequately capture local dynamics.

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