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Abdi Hanra Sebayang
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Sustainable in Energy Science and Technology
Published by Politeknik Negeri Medan
ISSN : -     EISSN : 31095909     DOI : https://doi.org/10.51510/siest
Core Subject : Science, Engineering,
Chemical Engineering, Chemistry & Bioengineering Chemistry Energy Engineering Industrial & Manufacturing Engineering Materials Science & Nanotechnology Mechanical Engineering Physics
Sustainable in Energy and Science Technology (SiEST) aims to serve as a multidisciplinary platform for the dissemination of cutting-edge research, innovation, and advancements in the fields of sustainable energy, environmental science, and technological artificial intelligent development. The journal seeks to address global challenges related to energy systems, environmental sustainability, and the integration of science engineering and modelling technologies to promote a sustainable future. The journal publishes high-quality and high-impact Original Research Articles, Review Articles and Short Communication Articles on cutting-edge innovations in research, and recent advances or issues of interest to the energy and science technology community. Sustainable in Energy and Science Technology Scope: 1. Sustainable Energy Systems 2. Applied Engineering and Environmental 3. Physical Sciences 4. Chemical Sciences 5. Engineering Technological Advancements
Arjuna Subject : Energi (semua kategori) - Energi Terbarukan, Keberlanjutan dan Lingkungan
Articles 10 Documents
 1 
Second-Generation Bioethanol Production Using Hydrolytic Treatment of Durian Seed Aulia Djati Pramiesta; H.C. Theofany; Naurah Rizki Fajrini; H.B. Aditiya; Teuku Meurah Indra Riayatsyah
Sustainable in Energy Science and Technology Vol. 1 No. 1 (2025): Sustainable in Energy and Science Technology
Publisher : Politeknik Negeri Medan

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.51510/siest.v1i1.2573

Abstract

Second-generation bioethanol produced from non-edible feedstocks and agricultural waste is a promising alternative to fossil fuels. In this study, durian (Durio zibethinus) seeds – an abundant fruit waste in Indonesia (over 1.14 million tons of durian fruit produced in 2018) – were utilized as a starch-rich feedstock for bioethanol. A microwave-assisted alkaline hydrolysis method was applied and optimized to release fermentable sugars for subsequent bioethanol production. A Box–Behnken experimental design was used to examine the effects of four parameters: NaOH concentration (0.5–1.0 M), durian seed loading (2–4 g/100 mL), microwave irradiation time (2–4 min), and microwave power (200–400 W). Reducing sugar yield (glucose equivalent) was quantified by the dinitrosalicylic acid (DNS) method. The maximum reducing sugar concentration achieved was 2.256 g/L, corresponding to a theoretical ethanol yield of approximately 1.305 g/L. The optimum condition was observed at 4 g durian seed loading, 1 M NaOH, 400 W microwave power, and 4 min irradiation. Regression analysis indicated that microwave power and time had the most significant positive effects on sugar yield, while substrate loading had a moderate effect and alkali concentration the least. These results demonstrate the viability of durian seed waste as a feedstock for bioethanol and provide an optimized set of hydrolysis conditions. However, due to experimental constraints, fermentation of the hydrolysate was not performed; instead, theoretical ethanol yield was calculated. Future work should integrate an actual fermentation step to confirm ethanol production.
Techno-Economic Study of Biodiesel Generation from Sterculia foetida Seeds Bilqist Imeilia Az Zahra; H.C. Theofany; Teuku Meurah Indra Riayatsyah; H.B. Aditiya; Bidattul S Zainal
Sustainable in Energy Science and Technology Vol. 1 No. 1 (2025): Sustainable in Energy and Science Technology
Publisher : Politeknik Negeri Medan

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.51510/siest.v1i1.2574

Abstract

As fossil fuel reserves diminish and energy demand grows, biodiesel from non-edible oils has emerged as a promising renewable alternative. This study evaluates the feasibility of producing biodiesel from Sterculia foetida (Java olive) seeds, which contain 50–60 % oil. A second-generation biodiesel plant is designed and simulated using SuperPro Designer, covering oil extraction, transesterification, product purification, and by-product recovery. The plant processes 4,396 kg of seeds per hour in Lombok (Indonesia). Material and energy balances indicate nearly complete conversion to biodiesel, yielding ~16.19 million kg/year with a 0.001 % mass balance error. The total utility power demand is 6.2 million kWh/year, with the transesterification reactor consuming ~27 %. Economic evaluation (2021 USD) shows a capital investment of ~$3.82 million and annual operating cost of ~$20.72 million. At a biodiesel price of $1.00/L, annual revenue is ~$21.47 million, including ~$2.4 million from glycerol and co-products. Profitability metrics are positive: gross margin 3.48 %, ROI 19.67 %, payback period 5.08 years, IRR 9.14 %, and NPV ~$1.03 million. Sensitivity analysis shows profitability is most affected by biodiesel market price and feedstock cost. Overall, biodiesel production from Sterculia foetida is technically feasible and economically viable, diversifying Indonesia’s biodiesel feedstocks.
Mechanical Characterization of Crispness in Dry Foods via Multi Specimen Compression Testing Dara Ginanti; Kushendarsyah Saptaji; Sri Hastuty; Farid Triawan
Sustainable in Energy Science and Technology Vol. 1 No. 1 (2025): Sustainable in Energy and Science Technology
Publisher : Politeknik Negeri Medan

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.51510/siest.v1i1.2575

Abstract

Texture is a critical quality attribute of dry snack foods, with crispness being especially important for consumer enjoyment. However, crispness is often judged subjectively by sensory evaluation, leading to ambiguity and inconsistency. This study develops a quantitative mechanical method to characterize crispness in dry foods using a multi-specimen uniaxial compression test that simulates human biting. Cassava chips (at three slice thicknesses) and a traditional dried Sus cake were tested in batches within a custom container under identical conditions. Statistical analysis (ANOVA) confirmed that these parameters notably differentiate samples (at P < 0.20 level) and correlate with sensory crispness rankings. The thinnest cassava chips (1 mm) exhibited the highest crispness (lowest energy and slope, highest jaggedness), whereas thicker chips were less crisp. Notably, the dried Sus cake, despite its different origin, showed higher crispness metrics than even the thinnest cassava chips, aligning with sensory perception. These results demonstrate that the proposed multi-specimen compression test can quantitatively distinguish crispness levels in foods of irregular shape. This study offers a qualitative data of crispiness on multi-specimen basis for specimen with random shapes by using the uniaxial compression test with two parallel plates. The key variables taken into account are the strain energy, mean slope of the stress-strain curve, and the jaggedness of the load-displacement curve.
Literature Review: Computational Methods for Designing Thermostable, Efficient, and Cost-Effective Enzymes for Industrial Applications Prisca Caesa Moneteringtyas; Nahzim Rahmat; Inten Pangestika; Sri Rahayu Widya Ningrum; Annisa Fillaeli; Aliyah Aliyah
Sustainable in Energy Science and Technology Vol. 1 No. 1 (2025): Sustainable in Energy and Science Technology
Publisher : Politeknik Negeri Medan

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.51510/siest.v1i1.2578

Abstract

Enzymes play a vital role as biocatalysts in various industrial applications due to their high specificity and efficiency under mild conditions. However, their limited thermostability significantly constrains their operational lifespan and effectiveness at elevated temperatures. This review examines recent advancements in computational methods aimed at enhancing enzyme thermostability, focusing on structure-based rational design, machine learning, and hybrid approaches. Key findings highlight the effectiveness of structure-based methods, in optimizing enzyme structures, while machine learning approaches demonstrated potential in predicting stabilizing mutations. This review identifies key research gaps and proposes directions for future studies to facilitate the industrial adoption of thermostable enzymes.
Modified Zeolite-Based Composite as Urea Slow-Release Fertilizer – A Mini Review Siti Mahmudha; Taranipa Marfitania; Muhammad Idris; Sulwiyatul Kamariyah Sani; Pina Budiarti Pratiwi; Eko Pujiyulianto
Sustainable in Energy Science and Technology Vol. 1 No. 1 (2025): Sustainable in Energy and Science Technology
Publisher : Politeknik Negeri Medan

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.51510/siest.v1i1.2579

Abstract

Urea is the most commonly used nitrogen fertilizer in agriculture due to its high nitrogen content and low cost. However, its efficiency is often below 50% because of nitrogen losses through leaching, volatilization, and surface runoff. To reduce these losses and improve fertilizer efficiency, slow-release fertilizers (SRFs) using modified zeolite-based composites have been developed. Zeolite is a porous aluminosilicate mineral with excellent ion exchange and adsorption properties, making it a good carrier for urea. However, natural zeolite has limitations, such as impurities and low surface area, which can be improved through modification techniques like acid–base treatments (dealumination and desilication), surfactant modification, and combination with organic or inorganic materials. These modifications improve pore size, surface area, and nutrient-holding capacity, allowing for a slower and more controlled release of nitrogen. This mini review discusses recent studies on the preparation, characterization, and performance of modified zeolite composites for urea delivery, showing their potential to reduce environmental impact and increase nutrient use efficiency in agriculture.
Design and Fabrication of a Body-Powered 3D-Printed Finger Prosthesis for Trans-Phalangeal Amputation Desinta Dewi Ramadani; Farid Triawan; Muslimin
Sustainable in Energy Science and Technology Vol. 1 No. 2 (2026): Sustainable in Energy Science and Technology
Publisher : Politeknik Negeri Medan

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.51510/siest.v1i2.3059

Abstract

High cost and ongoing maintenance requirements keep many finger amputees in underdeveloped nations from accessing prosthetic devices. The most prevalent upper-limb amputation, trans-phalangeal amputation (accounting for about 78% of cases), is addressed in this paper as requiring a low-cost, effective finger prosthesis. Using a single degree-of-freedom (1-DOF) connection mechanism and additive manufacturing, a body-powered prosthetic finger was designed and built. Aiming to restore fundamental grip function, the device is customisable to the user's hand size. Defining user needs (affordability, simplicity of use, comfort), investigating several four-bar linkage designs, and kinematic analysis optimisation of the mechanism constituted the design process. Using fused deposition modelling (FDM) 3D printing with polylactic acid (PLA), a prototype was created and evaluated for range of motion and load capacity. With a straightforward tether actuation by the remaining finger, the last prosthesis effectively simulates natural finger bending from extended to curled states. Lightweight and easy to wear, it survived lifting items up to a particular weight—on the order of a few kilograms—before mechanical slip occurred. The 3D-printed finger prosthesis shows that a low-cost, body-powered device can restore fundamental grasp abilities for trans-phalangeal amputees. Further studies will include user trials to assess long-term comfort and function as well as material enhancements for durability.
Thermodynamic Analysis of LPG Expansion in Direct-Injection Spark-Ignition Engines: Isenthalpic vs Isentropic Modeling Fauzan Azima; Aditya Harjon Bahar; Taufiq Bin Nur
Sustainable in Energy Science and Technology Vol. 1 No. 2 (2026): Sustainable in Energy Science and Technology
Publisher : Politeknik Negeri Medan

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.51510/siest.v1i2.3073

Abstract

Liquefied petroleum gas (LPG) fuel in modern direct-injection spark-ignition (DISI) engines must be modeled carefully to predict combustion behavior. In this work, we reformulate a student project into a research manuscript by comparing isenthalpic (Joule–Thomson) versus isentropic (ideal adiabatic) expansions of liquid LPG (propane surrogate) during injection. Using REFPROP thermophysical data and MATLAB simulations, we vary fuel rail pressures (45–100 bar) and fuel temperatures (30–85 °C) to determine critical flow properties at the injector throat (Mach 1 conditions). The choking point is identified by iterating pressure drop until the Mach number reaches unity in either a single-phase or two-phase region. We compute the resulting flashing ratio (liquid volume to vapor volume) for each model. Our results show that fuel temperature has a far greater effect on the speed-of-sound drop than rail pressure across all models, with higher temperatures yielding smaller acoustic drops. Nearly all cases produce flashing ratios Rp>1 (indicating significant vaporization), except under the second isenthalpic model where Rp falls below unity. Notably, the isentropic, first-isenthalpic, and isothermal models best reproduce a reference spray flash pattern, but their flashing ratios are very similar. Thus, we cannot definitively rank one model superior. Our analysis highlights that isentropic expansion yields a larger temperature drop than isenthalpic throttling, consistent with thermodynamic theory. The isentropic and first isenthalpic models predict almost identical choked-flow velocities and speed-of-sound behavior, whereas deviations appear only under the nonideal (second isenthalpic) cases. In summary, this modeling confirms that choosing a flash expansion assumption has only a subtle effect on predicted LPG fueling, provided the two leading models are considered.
Ultrasound-Assisted Lipid Extraction of Chlorella sp. for Biodiesel Production: Optimization Study Yheni Mulyaningsih; Aditya Harjon Bahar; Fazril Ideris; Rico Aditia Prahmana
Sustainable in Energy Science and Technology Vol. 1 No. 2 (2026): Sustainable in Energy Science and Technology
Publisher : Politeknik Negeri Medan

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.51510/siest.v1i2.3076

Abstract

Microalgae are a promising third-generation biofuel feedstock due to their high lipid and carbohydrate content. In this study, Chlorella pyrenoidosa biomass was subjected to alkaline hydrolysis to release fermentable substrates, and the process was optimized using a Box–Behnken response surface methodology. The key parameters – microalgal concentration, NaOH concentration, temperature, and hydrolysis time – were varied to maximize reducing sugar yield. The experimental data were fitted to a statistical model (R²>0.99), which identified significant positive effects of higher biomass loading and longer hydrolysis time on sugar release. Under the optimal conditions, the model predicts a maximum sugar concentration (approximately 0.47–0.50 g/L) from the hydrolysate. These results demonstrate the feasibility of converting Chlorella biomass into biofuel precursors. The findings are discussed in relation to biodiesel production strategies: for example, ultrasound-assisted extraction methods have achieved ~18.8% lipid yield from Chlorella under optimized conditions. Future work should integrate ultrasound pretreatment and lipid recovery (e.g. direct transesterification) to fully exploit microalgal biofuel potential.
Low Cost Non-Contact Measurement of Damping and Vibration Rhainna Rheizkhira Reflin
Sustainable in Energy Science and Technology Vol. 1 No. 2 (2026): Sustainable in Energy Science and Technology
Publisher : Politeknik Negeri Medan

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.51510/siest.v1i2.3091

Abstract

Understanding material dynamic behavior is crucial for designing structures subject to vibration. While static properties are often emphasized in engineering education, dynamic properties such as natural frequency and damping ratio are less frequently measured. This work presents an ultrasonic-sensor-based apparatus for measuring these dynamic properties of cantilever beam specimens. The prototype uses an HC-SR04 ultrasonic time-of-flight sensor and an Arduino microcontroller to record beam vibration. An exponential decay envelope analysis is applied to the displacement time history to determine the damping ratio. A piezoelectric accelerometer provides reference measurements for validation. Experimental tests on aluminum and 3D-printed PLA beams were conducted, and the measured frequencies and calculated damping ratios closely matched analytical and finite-element predictions. Sensor calibration was performed, yielding a correction factor of ~0.887 to improve accuracy. After calibration, frequency errors were below 5%. The apparatus reliably determines natural frequency and damping ratio, offering a simple, low-cost alternative to conventional methods. This system can serve as an effective educational tool for demonstrating vibration measurement and material dynamic behavior.
Material Properties of Recycled Polypropylene/Polyethylene Terephthalate for Rooftop Applications Fatima Tasya Kamila
Sustainable in Energy Science and Technology Vol. 1 No. 2 (2026): Sustainable in Energy Science and Technology
Publisher : Politeknik Negeri Medan

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.51510/siest.v1i2.3092

Abstract

Plastic waste management remains a major challenge, particularly for multi-material plastics such as polypropylene/polyethylene terephthalate (PP/PET) composites commonly used in packaging. This study applies a circular economy approach by recycling a PP/PET blend (95% PP, 5% PET) with maleic anhydride compatibilizer contents of 3%, 7%, 10%, and 13%. Recycled samples were produced via extrusion, granulation, and injection molding, then evaluated for density, tensile properties (7 mm and 2 mm thicknesses), hardness (Shore D), and Izod impact strength. The results were compared with two commercial PVC roofing products. The 13% compatibilizer sample showed the highest density and impact resistance, while the 3% sample exhibited the best tensile strength at 7 mm thickness and the highest hardness. Overall, increasing compatibilizer content did not lead to significant property improvements. The 3% compatibilizer formulation was identified as the most effective for rooftop applications, offering competitive performance with minimal additive use. Compared to PVC roofing, recycled PP/PET achieved comparable density, tensile strength, and impact resistance, although PVC remained stiffer.

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