Indonesian Journal of Science and Technology
This web is a backup web for The Indonesian Journal of Science and Technology (IJoST) in https://ejournal.upi.edu/index.php/ijost. All submissions and reviewing must be done in https://ejournal.upi.edu/index.php/ijost. The Indonesian Journal of Science and Technology (IJoST) (ISSN: e.2527-8045 p.2528-1410) is an open-access and peer-reviewed journal, published by Universitas Pendidikan Indonesia, which dissemination of research results from scientists and engineers in many fields of science and technology. In 2016-2020, IJoST was issued in April and September. Since 2020, IJoST issues 3 times a year (April, September, and December). The editors welcome submissions of papers describing recent theoretical and experimental research related to (1) Theoretical articles; (2) Empirical studies; (3) Case studies; and (4) Literature Review.
Computational Engineering of Malonate and Tetrazole Derivatives Targeting SARS-CoV-2 Main Protease: Pharmacokinetics, Docking, and Molecular Dynamics Insights to Support the Sustainable Development Goals (SDGs), with a Bibliometric Analysis
This research applies computational engineering to explore malonate and tetrazole derivatives as potential inhibitors of the SARS-CoV-2 Main Protease. A comprehensive in silico approach, including pharmacokinetics prediction, molecular docking, and molecular dynamics simulations, was utilized to evaluate the drug-likeness, binding affinity, and stability of the designed compounds. The malonate derivatives demonstrated strong interaction stability with the target protease and exhibited favorable pharmacokinetic profiles with minimal predicted toxicity, supporting their potential as therapeutic candidates. A bibliometric analysis was also performed to position this study within the broader scientific landscape, showing increasing global interest in SARS-CoV-2 protease inhibitors and antiviral drug development. This work aligns with the Sustainable Development Goals by contributing to global health improvement and fostering innovation in pharmaceutical engineering. The promising computational outcomes underscore the need for further experimental validation to confirm therapeutic efficacy and safety, potentially contributing to future antiviral treatment strategies.
Copyright (c) 2025 Universitas Pendidikan Indonesia https://creativecommons.org/licenses/by-sa/4.0
Integrating Multi-Stakeholder Governance, Engineering Approaches, and Bibliometric Literature Review Insights for Sustainable Regional Road Maintenance: Contribution to Sustainable Development Goals (SDGs) 9, 11, and 16
This study analyzes the Provincial Road Improvement and Maintenance (PRIM) program in Lombok Barat, Indonesia, which integrates technical engineering frameworks with multi-stakeholder governance mechanisms to improve road maintenance performance. Using a case study approach, data were collected through official government records, complaint management systems, multi-stakeholder forum documentation, and bibliometric analysis of global research trends. Life Cycle Cost Analysis (LCCA) demonstrated that preventive maintenance under PRIM reduced total life cycle costs by 28-35% compared to reactive maintenance models. The establishment of the Road Traffic and Transportation Forum (FLLAJ) and implementation of the Anti-Corruption Action Plan (ACAP) strengthened transparency, accelerated complaint resolution within seven working days, and enhanced public trust. The PRIM model successfully aligned technical efficiency with governance innovation while directly contributing to multiple Sustainable Development Goals (SDGs) 9, 11, and 16. The findings offer practical lessons for other developing regions seeking to institutionalize integrated infrastructure governance frameworks that simultaneously optimize service quality, fiscal sustainability, and institutional accountability.
Adaptive Robust Confidence Bands on Local Polynomial Regression Using Residual Bootstrap Percentiles
Ensuring reliable inference in local polynomial regression requires robust methods that can manage data irregularities, particularly outliers. This study introduces an adaptive robust approach for constructing confidence bands using residual bootstrap percentiles. Two robust weighting techniques (Huber and Tukey) were applied to address different levels of data contamination. The method was evaluated using both simulated datasets and real-world observations involving fluctuating patterns. Huber weighting produced more stable and narrower confidence bands under moderate anomalies, while Tukey weighting was more effective in handling extreme deviations. These differences arise because Huber downweights moderate residuals proportionally, whereas Tukey aggressively suppresses extreme outliers. Smoothing parameters were optimized through cross-validation to balance bias and variance effectively. This approach enhances the robustness of nonparametric regression because it maintains consistent confidence coverage despite data imperfections, offering a reliable tool for statistical inference in complex datasets.
Numerical Simulation of Deep Mixed Columns Beneath the Heavy-Haul Railway Embankment
One approach used to modify loose sand settlement under railway embankment involves deep mixed columns (DMCs). The geometrical properties of DMCs, such as the length, diameter, and spacing between adjacent columns, affect the distribution of load, failure mechanism, and ultimate resistance of a foundation constructed above soil reinforcement by this method. Numerical analysis is used as an alternative to laboratory modelling to minimize the cost and simplify the creation of complex DMC geometries in the lab. In this research, 3D Plaxis models are used to examine the influence of DMCs constructed under the embankment of a heavy-haul railway. The model used in this study has been calibrated and adjusted based on historical data from experimental tests on silty sand with low relative density. The study results offer details on how the bearing capacity of loose soil below train embankments is affected by the length and spacing of columns under static and dynamic loads.
Effect of Solvent Pre-Treatment and Catalyst on Microwave-Assisted Pyrolysis of Rice Straw
The microwave-assisted pyrolysis (MAP) application of rice straw as feedstock is the primary focus of this research. Some of the solvents that were utilized for soaking feedstocks included benzene, acetone, and ethanol. These solvents were used to pre-treat the rice straw. Through the use of solvents, yields were increased, reaction times were decreased, and the pyrolysis index was improved. KOH catalyst increased the amount of gaseous products produced by 47.5 wt%. When rice straw was prepared with benzene, the average heating rate decreased to 21.8 °C/min, significantly increasing the amount of oil and char produced. Rice straw that had been prepared with acetone had a much lower energy consumption in MAP (283 kJ) when compared to fresh rice straw, which had a different energy consumption (418 kJ). In the process of pyrolysis, it is demonstrated that solvent soaking occupies a significant position. The recovered bio-oil also included mono-aromatics, poly-aromatics, and oxygenated compounds.
Enhanced Product Defect Detection in Smart Manufacturing Using ConvNeXt-Stacked Autoencoder Architecture
In the era of Industry 4.0, ensuring product quality through accurate and efficient defect detection has become essential because traditional manual inspection methods are often time-consuming and prone to inconsistency. This study aims to enhance defect detection in smart manufacturing by proposing a hybrid deep learning architecture that combines ConvNeXt and stacked autoencoders. The method leverages ConvNeXt for robust feature extraction and stacked autoencoders for efficient data reconstruction and classification. The model was trained and tested on real-world industrial image datasets involving damaged and intact packaging. Results demonstrate that the proposed method outperforms conventional convolutional neural networks in both detection accuracy and processing efficiency because of its ability to extract deep spatial and semantic features. This research contributes to the advancement of autonomous quality control systems in smart manufacturing. Its impact lies in reducing human dependency, improving inspection accuracy, and fostering the development of intelligent, self-regulating production lines.
Measurement and Quantitative Analysis of Ozone Generation in Radiation Treatment Room Due to High-Energy Photon
Ozone generation in radiation treatment rooms poses a health risk due to high-energy photon interactions with air molecules. This study quantifies ozone concentration under varying conditions and assesses its impact on occupational exposure. Using a self-designed phantom, ozone measurements were taken under various conditions, including different photon energies (i.e., 6 and 15 MV), dose rates (i.e., 300 and 600 MU/min), and doses (i.e., 500 and 1,000 MU), with each condition measured ten times. Results showed that ozone concentration increased significantly with higher photon energy and dose, while the dose rate had a minimal effect, except at 15 MV. The highest ozone level (0.161 ± 0.003 ppm) exceeded FDA medical device limits and air quality standards. Ozone persisted for six minutes before normalizing, posing potential health risks to workers. These findings highlight the need for improved ventilation strategies in radiation treatment rooms.
Chemical Looping Systems for Hydrogen Production and Their Implementation in Aspen Plus Software: A Review and Bibliometric Analysis
Hydrogen (H₂) production is a key strategy for reducing greenhouse gas emissions, providing a clean and efficient energy alternative. This review explores chemical looping combustion (CLC) for H₂ production, focusing on feedstocks, oxygen carriers (OCs), and process modeling in Aspen Plus®. A bibliometric analysis was conducted to support the review. Results indicate that methane (CH₄) outperforms biomass due to its higher efficiency and stable reaction behavior. Iron- and nickel-based oxides are the most effective OCs, with iron facilitating water splitting and nickel excelling in steam methane reforming (SMR) and chemical looping reforming (CLR). Enhancing OCs with support materials and sorbents improves system performance. Accurate simulations using Rgibbs and fluidized bed models are essential for optimizing the process. This study provides insights into improving H₂ production efficiency, contributing to advancements in clean energy technologies.
Synthesis and Investigation of Dithiocarbamate Derivatives as Polyfunctional Ingredients in Rubber Compounds
The synthesis of dithiocarbamate derivatives and their potential application as accelerators and anti-degradants in rubber compounds have been investigated. The physico-mechanical properties of vulcanizates based on IR SKI-3 and their resistance to thermo-oxidative aging have been determined. The influence of the obtained compounds on the dynamic properties of the composition has been established. Partial replacement of captax with synthesized 2-fluorophenyl dithiocarbamate triethylamine allows maintaining the strength at the level of the control sample. At the same time, the rubbers exhibit increased resistance to dynamic loads and comparable values of the tangent of mechanical loss angle at high deformation levels compared to vulcanizates containing only captax. This effect is achieved by increasing the polarity of the radical and improving the mobility of the chains of rubber macromolecules, which is confirmed by the calculation of the time spectrum of relaxation for mechanical vibrations under shear deformations. Also, the synthesized product has a positive effect on the resistance of rubber to thermal-oxidative aging.
Optimization of Hybrid Core Designs in 3D-Printed PLA+ Sandwich Structures: An Experimental, Statistical, and Computational Investigation Completed with Bibliometric Analysis
This work presents the experimental test and Finite Element Analysis (FEA) of six core profiles (i.e. Square, Circle, Ellipse, Octagon‎, ‎Pentagon, and Hexagon grids) on mechanical properties of 3D-printed Polylactic Acid Plus (PLA+) sandwich ‎panels. Tensile and ‎flexural tests were carried out to evaluate the structural performance of each core ‎geometry; FEA in Abaqus was employed to study the stress distribution and ‎deformation patterns. In contrast, the mechanical properties were the highest for the hexagonal and pentagonal cores ‎with ‎tensile strengths of 45.2 and 43.8 MPa, respectively, and flexural strengths of 290 and 323 ‎MPa, respectively. ANOVA and Tukey's HSD tests indicated that core geometry significantly ‎influences the flexural strength of sandwich panels of 0.94. The new hybrid hexagonal-octagonal core ‎geometry was henceforth proposed to continue the quest for structural efficiency. The integration of the experimental and numerical approaches in such a way that validates the reliability of the FEA model itself gave less than 6% error in predicting flexural strength.
A Study on Sustainable Eggshell-Derived Hydroxyapatite/CMC Membranes: Enhancing Flexibility and Thermal Stability for Sustainable Development Goals (SDGs)
Carboxymethyl cellulose (CMC) is a biopolymer with promising biomedical applications, and its properties can be enhanced through hydroxyapatite (HA) incorporation. This study synthesized HA from chicken eggshells via the hydrothermal method, aligning with Sustainable Development Goals (SDGs) by valorizing biowaste. The synthesized HA exhibited 35.24 nm crystal size and 86.98% crystallinity. HA was integrated into CMC membranes (i.e. 1 and 5%), with and without polyethylene glycol (PEG-400; as a plasticizer). Increased HA content reduced membrane flexibility, but PEG-400 improved structural cohesion. Microscopic analysis revealed better HA dispersion at 5% loading, enhancing membrane performance. Thermal gravimetric analysis confirmed improved thermal resistance, evidenced by a higher decomposition onset temperature. These findings suggest that CMC/HA composite membranes, especially with PEG-400, offer sustainable solutions for biomedical applications, demonstrating superior mechanical and thermal properties while promoting eco-friendly material utilization from biowaste.
Ganciclovir-Loaded Chitosan Nanoparticles and Their Activity against HSV-1 Inducing Herpetic Retinitis
Herpes simplex virus (HSV)-1-induced retinitis is one of ophthalmic viral infections. It is found in some immunocompromised and elderly patients and is a cause of complete blindness. Nowadays, an intravitreal (IVT) injection of ganciclovir (GCV) is applied to treat this disease. Unfortunately, frequent IVT injections induce adverse effects in the eye. GCV-loaded chitosan nanoparticles (GCV-CS-NPs) were developed to reduce the number of IVT injections. This study developed GCV-CS-NPs and investigated their activity against HSV-1. GCV-CS-NPs were prepared using an ionic gelation method with varying formulation compositions. The particle size, polydispersity index (PDI), zeta potential, pH, drug release, and activity against the HSV-1 were investigated. The results showed GCV-CS-NPs with particle sizes of around 161 to 294 nm, moderate PDI values, and zeta potentials of between +8.0 and +18.1 mV. These properties strongly depended on the formulation compositions. The release rate of GCV from the optimized GCV-CS-NPs (3C-0.5G-1T-4.5) in the simulated vitreous humor regarding Higuchi’s model was 4.89±0.48 µg/min1/2. The IC50 against the HSV-1 was 25.12±0.02 µg/mL. 3C-0.5G-1T-4.5 could be accepted as a promising delivery system of GCV to the vitreous humor via IVT injection and had a potential for being subjected to further in vivo studies.
Optimization of Piper Trilinier Diagram Using Lithium Isotope Systematics: An Application for Detecting the Contribution of Geothermal Water from Aso Caldera after Earthquake 2016 in Kumamoto Aquifer, Japan
Optimization of the use of the Piper trilinear diagram was carried out by adding Lithium isotope systematics as a more accurate water-type analysis. The method used in this research is to analyze the Cl/Li ratio > 1000, δ7Li < 10 ‰, and Lithium concentration of groundwater, and then the results of the analysis are integrated into a Piper trilinear diagram. The research results show that Lithium isotope systematics (Cl/Li ratio < 1000, δ7Li < 10 ‰ and Li concentration) graph can be divided into 3 regions, namely geothermal water type has Cl/Li < 1000 and δ7Li < 10 ‰, then shallow groundwater which has Cl/Li > 1000 but δ7Li < 10 ‰ experienced natural contamination from geothermal waters, and fluid that has a Cl/Li ratio > 1000 and 10 ‰ > δ7Li > 20 ‰ is estimated to be shallow groundwater.
Development of Green Polybag Innovation Products from Biomass Waste as Planting Media
Green polybags offer an eco-friendly alternative to conventional plastic polybags, which pose environmental concerns due to their slow decomposition. This study explores the optimal composition of empty fruit bunches (EFB), sawdust waste (SW), and natural rubber latex (NRL) to develop biodegradable green polybags that function as both containers and planting media. The best formulation—EFB 140 g, SW 40 g, and NRL 60 g—exhibited a density of 0.6762 g/cm³, moisture content of 6.71%, water absorption of 45.28%, and biodegradation rate of 29.91%. Seedlings grew successfully in this medium, demonstrating its effectiveness. FTIR analysis confirmed the presence of hydroxyl, carbonyl, aliphatic, and ester groups, while SEM-EDX analysis indicated high carbon and oxygen content in EFB and SW. The results suggest that green polybags are a sustainable and biodegradable alternative, promoting environmental conservation and plant growth.
Activated Carbon Films from Water Hyacinth Waste for Stable and Sustainable Counter-Electrode Application in Dye-Sensitized Solar Cells
This study explores the synthesis and application of water hyacinth-activated carbon (WHAC) as a counter-electrode in dye-sensitized solar cells (DSSCs). Characterization analyses, including X-ray diffraction, Raman spectroscopy, Fourier-transform infrared spectroscopy, and the N2 adsorption-desorption isotherm, confirmed the polycrystalline and mesoporous nature of WHAC, whose pore size and surface area are 3.06 nm and 176.7 m2/g, respectively. WHAC films deposited on the fluorine-doped tin oxide presented rough, random surface morphologies and thicknesses at higher concentrations. Optimized WHAC-based DSSCs presented a 1.40 ± 0.16% power conversion efficiency (PCE) compared to the 1.66 ± 0.26% presented by the standard platinum-based counter-electrodes. The efficiency improvement in the case of the WHAC-based DSSCs was the result of efficient electron transport, evident from the low sheet resistance and stable redox characteristics. The findings suggest WHAC is a promising and sustainable catalytic material for DSSC counter-electrodes.
H2O2-Modified Geopolymers as Integrated Adsorbent-Catalysts for FFA Removal and Biodiesel Production from Crude Palm Oil
This study investigated hydrogen peroxide (H₂O₂)-modified geopolymers as integrated adsorbent catalysts for biodiesel production from crude palm oil (CPO). Geopolymers were synthesized using metakaolin and modified with varying H₂O₂ concentrations (0-30 wt%). Material characterization through XRD, FTIR, XRF, and BET analysis showed that H₂O₂ modification enhanced porosity and surface area, with modified samples showing a 13-fold increase in specific surface area (9.7068 m²/g) compared to unmodified geopolymer (0.7312 m²/g). The optimal H₂O₂-modified geopolymer (Gpm-3) demonstrated superior performance in separated and combined processes. The separated process achieved 85.38% FFA removal efficiency and 100% biodiesel yield. The combined single-step process maintained impressive performance with 55% FFA removal and 96.47% biodiesel yield. These results highlight the potential of H₂O₂-modified geopolymers as cost-effective, sustainable materials for integrated FFA removal and biodiesel production from CPO.
Enhanced Thermal Performance of Parabolic Through Collectors with TiO₂ Nanofluids in An Arid Climate
Solar energy is a crucial renewable resource, yet its efficient utilization remains a challenge because conventional heat transfer fluids have limited thermal conductivity. Parabolic Trough Collectors (PTCs) offer a viable solution for solar thermal energy conversion, but optimizing performance is essential for improving efficiency. This study investigates the performance of a PTC using a 0.3% TiO₂-water nanofluid compared to distilled water (DW) under real environmental conditions in Algeria’s arid climate. Two identical PTCs were tested outdoors at flow rates of 0.2, 0.3, and 0.4 L/min to evaluate heat transfer efficiency. The results demonstrated that the nanofluid consistently outperformed DW because of its superior thermal conductivity and heat retention. At 0.4 L/min, the nanofluid achieved 40% thermal efficiency, 9% higher than DW. However, as the flow rate decreased, the efficiency gap narrowed. These findings confirm the potential of nanofluids to enhance solar energy utilization, supporting sustainable energy solutions in high-irradiance regions.
Integration of Water Heating Systems with Car Air Conditioning Systems: A Bibliometric Analysis, Lab-scale Investigation, and Potential Applications
Automotive air conditioning (AC) systems, traditionally powered by the engine, contribute to reduced fuel efficiency and environmental challenges. However, the heat released by the AC condenser has the potential for energy reuse. This study aims to design and evaluate an integrated thermal management system that combines the functions of a water heater and an AC. A lab-scale system is developed to investigate the thermodynamic behavior of the refrigerant and assess the system performance at various cooling water flow rates. The results show an increase in the Energy Efficiency Ratio (EER) with this integration, which offers new applications, such as intercity buses by providing warm water for on-board toilets. This innovation not only improves passenger comfort but also improves energy efficiency and sustainability in transportation systems. The proposed integration is an example of a practical approach to utilize waste heat and address energy and environmental issues in modern vehicles.
Triazolopyrimidine Derivatives: A Comprehensive Review of Their Synthesis, Reactivity, Biological Properties, and Molecular Docking Studies
Triazolopyrimidines are heterocyclic compounds with a unique structure and a wide range of applications in medicinal chemistry. The versatility of the triazolopyrimidine scaffold allows for the exploration and development of compounds with diverse pharmacological properties. This literature review encompasses the period from 2014 to 2022 and offers a comprehensive and inclusive overview of the synthesis, reactivity, and biological properties studies of triazolopyrimidines. The review summarizes the various synthetic methods used to prepare triazolopyrimidines and their reactions with different reagents. It also examines their pharmacological properties, such as anti-COVID-19 and anticancer effects, and their molecular docking analysis with relevant targets. The review aims to contribute to a better understanding of the potential applications of triazolopyrimidine in the field of medicinal chemistry. This literature review from 2014 to 2022 provides a comprehensive exploration of triazolopyrimidines, highlighting their diverse applications in medicinal chemistry. The review aims to offer a thorough understanding of triazolopyrimidines' versatility, serving as a valuable resource for advancing drug development in medicinal chemistry.
How to do research methodology: From Literature Review, Bibliometric, Step-by-step Research Stages, to Practical Examples in Science and Engineering Education
This paper explains how to do research in science and engineering education. To support the explanation, the paper was supported by a literature review for research design and computational bibliometric analysis. We mapped several types of research methodologies, supported by several examples from researchers and practitioners who were involved in these research topics. We also developed 9 steps in research methodology, namely PHMEEDERID, an abbreviation of Identify Problems; Develop Hypothesis; Choose Research Methodology; Conduct Experiments and Create Equipment; Refine Design and Develop; Evaluate and Test; Do Revision and Retest; Implement; and Disseminate. The step-by-step method was also added to make readers and users easily understand. This study has the potential to be used as standard information for scientists, teachers, educators, and practitioners in doing research in science education and engineering education.
Chatbots as Digital Language Tutors: Revolutionizing Education Through AI
Artificial intelligence (AI) is changing the landscape of language education and AI-enhanced chatbots are in the process of becoming digital tutors. This study explores how chatbots enhance language acquisition through real-time, interactive, and personalized learning experiences. As virtual tutors, they allow students to repeat the vocabulary, grammar, pronunciation, and conversation skills in dynamic contexts and give immediate feedback to improve language. Multilingual features enable chatbots to reach a broad spectrum of learners addressing issues of scalability and accessibility. For teachers, chatbots extend themselves beyond conventional teaching, lessen workloads, and facilitate large-scale and multilinguistic programmes. It is important to have an easy-to-use, culturally-pragmatic design so that the integration in curricula can appropriately address learners' heterogeneous needs. Chatbots provide democratizing language education of top quality by circumventing cost and access barriers and offering life changing solutions for language learners worldwide. They offer real-world pointers to further develop AI-powered educational technologies, and thus, provide a platform for broader application to the language curriculum. As Artificial Intelligence develops, chatbots will be a fundamental tool for promoting linguistic and communicative competence in contemporary education.
Copyright (c) 2024 Universitas Pendidikan Indonesia https://creativecommons.org/licenses/by-sa/4.0
Research Trends in Wireless Communications Using Graphene: Research Trajectories in Antenna Applications
Communications require a large amount of network resources to support the heavy traffic generated by the Internet of Things (IoT). As a result, microelectronics and telecommunications have been exploring types of hardware capable of supporting these new network architectures and communication systems. New devices should be designed to offer high speed, ultra-wideband connectivity, and extensive coverage. In addition, they should use eco-friendly materials to respond to the needs of sustainable smart cities and meet the requirements of future communications. This literature review followed the PRISMA statement to identify research trends in the use of graphene in antennas for wireless communication applications. A total of 168 documents were analyzed, and one of the main findings is a considerable rise in research interest in this topic since 2012, with India emerging as the leading contributor of knowledge in this area. Furthermore, most applications have been developed for the terahertz band, and more recent studies have focused on utilizing MIMO technologies for 5G and 6G communication systems. In addition, most research has observed improvements in the performance and efficiency of antennas designed with graphene, observing in some results up to 9.35 dBi of gain and 97.6% in radiation efficiency for applications in the terahertz band.
Comprehensive Characterization of Gelatin Films from Goat Skin Incorporating Konjac Glucomannan: Physical, Mechanical, and Molecular Properties
This study aimed to comprehensively investigate and characterize the physical, mechanical, and molecular properties of gelatin films made from goat skin incorporated with konjac glucomannan. The study involved three treatment groups, labeled GG/KG1, GG/KG2, and GG/KG3, which included konjac glucomannan at concentrations of 0, 10, and 20% (w/w), respectively. Glycerol at 20% (w/w) was also included as a plasticizer. All samples underwent homogenization and ultrasonic treatment. The addition of konjac glucomannan to the gelatin-based film resulted in changes such as increased thickness (0.033 - 0.093 mm), opacity (0.9910 - 1.0433 mm-1), color L* (92.45 - 92.77), color difference (48.13 - 48.38), swelling (65.53 - 69.47%), and contact angle (86.92 - 127.85o). Conversely, a decrease was observed in water activity (0.521 - 0.463 Aw), moisture content (9.87 - 9.62%), tensile strength (0.0171 - 0.0118 N/mm2), elongation at break (5.91 - 4.52%), young’s modulus (0.0029 - 0.0026 N/mm²), WVTR (118.99 - 116.82 g/m². day), transparency (81.59 - 67.33%), and water resistance (34.47 - 30.53 %). Additionally, the peaks of amides A, B, I, II, and III exhibit both a shift and an increase in intensity, suggesting structural modifications and molecular interactions. The microstructure also indicated the presence of goat skin gelatin and konjac glucomannan cross-linked in the film formation. Therefore, the addition of konjac glucomannan modifies gelatin-based films, enhancing their suitability for food packaging.
Copyright (c) 202 Universitas Pendidikan Indonesia https://creativecommons.org/licenses/by-sa/4.0
Microwave Pyrolysis of Agricultural and Plastic Wastes for Production of Hybrid Biochar: Applications for Greener Environment
The microwave-assisted pyrolysis (MAP) is a promising technology for converting waste feedstocks (AWB and PW) into valuable products, primarily biochar. The residual product generated from the AWB and PW MAP process is called hybrid biochar. The hybrid biochar made by MP is highly stable, has distinctive physical and chemical characteristics, and outperforms its conventional usage. Microwave heating is an efficient and fast energy heating method. It helps with yield production, eliminates the need for liquid convection, makes thermal control easier, restores waste products' chemical and energy value, and produces the highest quality and most cost-effective hybrid biochar. Different feedstocks and microwave pyrolysis settings affect how well hybrid biochar restores the environment. This article examines hybrid biochar's potential to boost agricultural productivity, nutrient availability, co-composting, water retention, and consumption efficiency. The report also reveals knowledge gaps and suggests further research to better understand hybrid biochar deployment. The study also detailed hybrid biochar's production, characterization and, most importantly, environmental use.
Real-Time Analysis for Enhancement of Photovoltaic Panel Efficiency and Quality
This study addressed the quality assessment of photovoltaic (PV) panels by analyzing their efficiency and electrical power under varying environmental conditions. A sophisticated algorithm was developed to extract and analyze PV panel voltage and current data in a complex manner, allowing the identification of key parameters such as open circuit voltage (Voc), short circuit current (Isc), and peak electrical power. These parameters were compared to the input power to accurately determine the panel efficiency. The novelty of this approach lies in its real-time implementation using a DC/DC (buck-boost) converter equipped with precise voltage and current sensors and running on a TMS320f379D board, linking theoretical knowledge with practical results. Experimental results demonstrated that temperature and irradiation significantly influence PV performance. With a 10°C increase in temperature, it resulted in a 5-10% decrease in output power, while a 100 W/m² increase in irradiation resulted in a 10-15% increase in output power. The study highlights the importance of considering both temperature and irradiation variations to optimize PV system design and operation, providing a robust method to assess PV panel quality in real-time.
How to Calculate and Determine Chemical Kinetics: Step-by-Step Interpretation of Experimental Data to Get Reaction Rate and Order
hemical kinetics is a fundamental field of study that focuses on the rates of chemical reactions and the factors influencing them. Determining the rate and order of the chemical reaction is an important aspect of understanding the reaction mechanism. This article presents a step-by-step guide to calculate and determine the rate and order of the reaction through a comprehensive analysis of experimental data. We discussed the concept of chemical kinetics, the integration of the kinetic order method, and the curve-fitting analysis technique. Several case studies are also included to provide practical applications of the theory outlined. This proposed guide aims to provide students, educators, researchers, and practitioners with a systematic approach to specify and verify prospective kinetic models, enabling them in decision-making, improving, and optimizing chemical reaction processes.
Soft Coral Epibiotic Bacteria Vibrio alginolyticus from Sarangani Bay, Mindanao Philippines as Potent Source of Antibacterial Agent
This study aims to explore the antibacterial properties of the different epibiotic bacterial species thriving in the surface tissues of the soft corals, and their potential application in developing novel antibacterial agents. There were ten soft coral species randomly collected from Sarangani Bay in Mindanao, Philippines: 3 sarcophyton sp., two sinularia sp., 1 nepthia sp., 1 stenonephthya sp., 1 anthelia sp., 1 lithophyton sp. and 1 asteropicularia sp. All soft coral species collected harbored epibiotic bacteria. Fifteen epibiotic bacterial species were isolated and tested for antibacterial properties against Staphylococcus aureus (gram-positive) and Escherichia coli (gram-negative) as test organisms. Their respective zones of inhibition were compared to that of the commercial antibiotics Penicillin, Chloramphenicol, and Gentamycin (as positive controls). Results indicated varied antibacterial effects, with one isolate, Vibrio alginolyticus (EB6), showing significant activity, with the zone of inhibition of 9.33 mm against E. coli, comparable to that of Chloramphenicol and Gentamycin, with the zone of inhibition of 10 and 9 mm, respectively. These findings highlight the potential of marine-derived bacteria in developing new antibacterial agents.
Anatomical Characteristics and Taxonomic Significance of Rhizophoraceae Mangrove Leaves
Rhizophoraceae is a mangrove family that spread from landward to seaward zones and dominated Benoa Bay in Bali, Indonesia. Mangroves are already studied in many approaches but insufficient in anatomical approach. This research aims to determine the anatomical characteristics of Rhizophoraceae mangrove leaves in Benoa Bay, as well as determine the taxonomic significance. The research was conducted at four locations in Benoa Bay with four mangrove species: Bruguiera gymnorhiza, Ceriops tagal, Rhizophora apiculata, and Rhizophora mucronata. Leaf anatomical data was collected by using a modified free-hand section method to obtain leaf transversal structure and replica paradermal to obtain epidermal structure. The data analyzed descriptively and completed with a numerical taxonomy approach by dendrogram and principal component analysis (PCA). Mangrove leaves have general structures such as epidermis, palisade mesophyll, sponge mesophyll, vascular bundles, and stomata, as well as several typical structures such as hypodermis layer, calcium oxalate crystals, and sclereids. The results of the numerical taxonomic analysis revealed several characteristics with taxonomic significance were occurrence of astrosclereid, number of upper hypodermal layers, thickness ratio of hypodermal to lamina, thickness ratio of mesophyll palisade to sponges, thickness ratio of mesophyll sponges to lamina, and type of stomata.
High-Porosity Hydrochar From Oil Palm Empty Fruit Bunches Via Single-Step Hydrolytic Agent-Assisted Hydrothermal Carbonization
Empty fruit bunches (EFBs) discarded from the palm oil industry were converted into hydrochars with a high surface area via hydrolytic agent-assisted hydrothermal carbonization (HTC). The reaction temperature was varied (160, 200, 240, and 280 °C) for a constant reaction time of 2 h. The effects of the type of hydrolytic agent (H2O2 and H2SO4) on the hydrochar properties were investigated. The physical and chemical properties of the as-obtained hydrochars, such as surface area, porosity, morphology, functional groups, and elemental composition, were characterized. The results showed that the fixed carbon and carbon contents increased with increasing temperature. At 280 °C, the hydrochar produced via the H2SO4-assisted HTC process had the highest fixed carbon (38.35 wt.%) and carbon (72.65 wt.%) contents. In comparison, the hydrochar (O-EFB280h2) produced via the H2O2-assisted HTC process at 280 °C exhibited the highest surface area (479.19 m2/g) and pore volume (0.727 cm3/g), and it contained functional groups such as C-H, C=O, and C-O. The H2O2-assisted HTC process produced hydrochars with a high surface area that could be used in a variety of applications.
Light Intensity Distribution in the Room Using Light Dependent Resistor: Through the Engineering Design Process
This paper aims to determine the distribution of light intensity values in a room at a certain time using a Light Dependent Resistor (LDR) sensor by comparing the light intensity and sensitivity of the LDR in conditions of changing dark to light in the room. The distribution of light intensity is measured using a light sensor assisted by Arduino application, the results of the average light intensity value when changing from dark to light conditions will automate the lights to turn on and off. Thus, it is hoped that it can save electricity. This experiment was integrated with the engineering design process through the following stages: 1) Identification of the problem, 2) Discussion of problem-solving, 3) Designing, 4) Creating, redesigning, and evaluation tests, and 5) Sharing solutions. Indoor light intensity measurements were carried out for 7 days, from 00.00, to once every 3 hours the distribution of the light intensity values read was checked. The research results provide new findings that the average distribution of light when changing from dark to light at 05.36 - 05.37 indoors shows a value of 105-135 lx, while from light to dark at 18.07 - 18.08 shows a value of 75 - 88 lux. These results can be used in further research to determine values that can be input into coding to control LDR sensor automation in product development.