Applied Science and Engineering Progress

Sustainable Composite Products: Industry 4.0 to 5.0

Mon, 20 Oct 2025 00:00:00 +0700

Anaerobic Digestion: Technology for Biogas as a Source of Renewable Energy from Biomass—A Review

Mon, 20 Oct 2025 00:00:00 +0700

Anaerobic digestion (AD) is a conventional method for converting biomass into renewable energy, gaining renewed interest in recent years due to its potential for sustainable energy production. While the fundamental principles of AD are well-established, modern research primarily focuses on optimizing the process under various conditions to enhance efficiency and yield. This study provides a comprehensive assessment of AD, exploring the impact of pretreatment methods, inhibitors, and key parameters affecting its performance. Special emphasis is placed on substrates containing lignin or bacterial cells, which are identified as the most adaptable for pretreatment strategies aimed at improving AD efficiency. The analysis further evaluates existing methods for assessing improvements in AD across different systems, highlighting current challenges and the potential for developing enhanced evaluation techniques. The findings underscore the importance of exploring alternative renewable energy sources beyond fossil fuels, with AD serving as a promising solution. Understanding the interplay between pretreatment, process parameters, and inhibitor management is essential for advancing AD technology and achieving economically viable outcomes.

Is the Future of Energy Rotten? Novel Perspective on Tri-Phase Fermentation and the Food Waste Paradox

Rich Jhon Paul Latiza, Rugi Vicente Rubi, Jerry Olay, Allan Soriano — Mon, 20 Oct 2025 00:00:00 +0700

Annually, a staggering 1.3 billion tons of edible food are wasted globally, representing not only a substantial economic loss but also a squandered opportunity for sustainable energy production. While anaerobic digestion offers a potential pathway for valorizing this waste, its limitations in feedstock conversion efficiency and substrate versatility necessitate the exploration of innovative alternatives. This comprehensive perspective review elucidates the transformative potential of tri-phase fermentation (TPF), a groundbreaking approach that represents a paradigm shift in waste valorization by synergistically integrating solid-state fermentation (SSF), submerged fermentation (LF), and gas fermentation (GF) to derive bioethanol from food waste. This study highlights the successful integration of these three phases within the TPF framework, demonstrating effective carbohydrate breakdown in SSF, significant ethanol production in LF, and valuable product generation from syngas in GF. By harnessing the metabolic capabilities of diverse microorganisms and leveraging emerging technologies, TPF offers a holistic solution, effectively converting both the primary food waste and its residual byproducts into valuable bioethanol. This review critically examines the fundamental principles, comparative advantages, and inherent challenges associated with each fermentation phase, while also elucidating their potential for synergistic integration within the TPF framework. Furthermore, the technological and economic hurdles inherent to TPF are addressed, emphasizing the need for further research in strain engineering, process optimization, and downstream processing to enhance its commercial viability. This review accentuates and provides a comprehensive perspective on the urgent need for further research and development to fully unlock the transformative potential of TPF and promote a circular bioeconomy by converting food waste into valuable bioethanol, addressing both waste and energy challenges.

A New Fuzzy Sliding Mode Controller for 2-DOF Aero System with Pitch Disturbance

Gaurav Kumawat, Niraj Kumar Goswami, Jayashri Vajpai — Mon, 20 Oct 2025 00:00:00 +0700

The two-degree-of-freedom aero flight control simulator is a nonlinear, unstable, and multi-input multi-output system with gravitational disturbance in its pitch dynamics. Its attitude control is a challenging task with linear controllers. The fuzzy controller by parallel distributed compensation uses a combination of linear controllers. It is a simple method, but exhibits poor tracking performance under disturbance. This study presents a design of a fixed structure fuzzy sliding mode controller to track the desired trajectory for this system. A sliding mode controller is combined with the fuzzy controller using an integral sliding surface to overcome gravitational disturbance and track the attitude. Lyapunov’s method verifies the stability of the closed-loop system. To validate the proposed design, numerical simulations are carried out and compared with existing methods. The tracking responses of yaw and pitch point out fast convergence of error with minimum settling time in the presence of matched disturbances.

AI-Driven Detection of Tomato Leaf Diseases for Sustainable Agriculture

Swetha R. Kumar, Mogana Priya Chinnasamy — Mon, 20 Oct 2025 00:00:00 +0700

This study explores a novel approach for detecting diseases in tomato leaves through the application of neural networks, aiming to enhance early diagnosis and management strategies for farmers and plant pathologists. The research investigates nine prevalent diseases affecting tomato foliage, including Early Blight, Late Blight, Septoria Leaf Spot, Target Spot, Yellow Leaf Curl Virus, Bacterial Spot, Spider Mites, Leaf Mold, Tomato Mosaic Virus, and Healthy leaves, using pre-trained deep learning models, ResNet-34 and VGG16. A diverse dataset of tomato leaf images, exhibiting various disease symptoms under field and curated conditions, was pre-processed, labeled, and split into training (80%) and testing (20%) sets to fine-tune the models. Evaluation of the testing dataset revealed that ResNet-34 achieved a higher accuracy of 99% compared to VGG16’s 89%, demonstrating superior performance in disease classification. Precision, recall, and F1 scores further confirmed ResNet-34’s robustness, averaging 0.99 across classes. These findings highlight the efficacy of deep learning in agricultural disease detection, contributing to sustainable practices by enabling timely interventions, reducing crop losses, and minimizing pesticide use. The study underscores the potential of AI-driven solutions to transform tomato cultivation, paving the way for scalable, real-time applications in resource-constrained farming environments.

Comparative Study on Techno-Economic Analysis for Various Organosolv Fractionation of Bagasse in Thailand

Mon, 20 Oct 2025 00:00:00 +0700

Process simulation is a crucial tool for conducting techno-economic analyses of biomass fractionation processes, providing insights into technical and economic aspects to optimize efficiency, reduce costs, and enhance the viability of production. This study focuses on the development and comparison of three scenarios based on organosolv fractionation methods. The mass balance analysis revealed significant differences in product yields, with scenario 2 achieving the highest cellulose (7,240.23 kg/day) and lignin (900.13 kg/day) outputs, scenario 3 showing a balanced profile with high hemicellulose recovery (2,959.81 kg/day), and Scenario 1 offering moderate outputs for cellulose and lignin. Economic evaluation indicated that scenario 3 was the most cost-efficient, driven by reduced operating costs, while scenario 1 had the highest total capital and operating expenses. Sensitivity analysis demonstrated minimal variability across scenarios but highlighted the need to study product pricing and future returns. Toxicity evaluation identified scenarios 1 and 3 as safer options due to the lower hazard classification of chemicals used compared to scenario 2. Overall, Scenario 3 emerged as the most favorable for cost-efficient and safe production of cellulose and lignin, supporting its potential for industrial-scale applications.

Custom-Built Earth-Based Hypergravity Platform to Study Gravity and Light Tropisms on Soil-Grown Seedlings

Mon, 20 Oct 2025 00:00:00 +0700

Earth-based facilities to generate altered gravity provide valuable tools to study crop resilience and adaptation to non-terrestrial gravity, offering a cost-effective alternative to space-based studies. While centrifuges and clinostats simulate hypergravity and microgravity, respectively, their limited scale often restricts research to small, isolated systems, such as cell cultures or petri-dish seedlings, which lack complex interactions such as those in soil-grown plants. Addressing these limitations, this study aimed to develop a 1-axis hypergravity platform with adjustable chambers designed for soil-grown Zea mays seedlings, incorporating controllable gravity, lighting, and irrigation with real-time monitoring through ThingSpeak platform. This platform allowed investigation on how hypergravity (5 g) and photosynthetic photon flux density (6.80–12.95 µmol/m²/s) impact maize growth and morphological traits, including main root length (MRL), seminal root count (SRC), dominant seminal root length (DSRL), shoot length (SL), and leaf count (LC). Results showed that 5 g conditions with higher light levels (12.95 µmol/m²/s) enhanced root elongation and stable leaf counts, while seedlings in 1 g preferred moderate light (6.80–8.16 µmol/m²/s) to avoid growth limitations. Additionally, hypergravity strongly influenced root and shoot growth, promoting root elongation essential for plant stability or anchorage and nutrient uptake. These findings highlight the importance of adjusting gravity and light exposure to optimize growth, providing a basis for future strategies in controlled agricultural systems for terrestrial and extraterrestrial applications.

Effects of Pulsed Laser Repetition Rate and Duty Cycle on Heat-Affected Zone Narrowing in Laser Powder Bed Fusion of 316L Stainless Steel

Mon, 20 Oct 2025 00:00:00 +0700

Laser Powder Bed Fusion (L-PBF) is a type of metal additive manufacturing process. It has attracted increasing interest over the past few decades. L-PBF systems typically use continuous wave (CW) emission. Recently, pulsed wave (PW) emission has been introduced in order to have better control of the heat-affected zone (HAZ) and potentially enhance spatial resolution. Generally, the PW emission involves the laser temporal profile that can be modulated by such as pulse durations, duty cycles, and pulse repetition rates (PRR). Nevertheless, based on a literature survey, the systematic investigation of pulsed wave (PW) emission in the L-PBF process, which changes the laser temporal profile by adjustment of the pulsed laser parameters has scarcely been examined. The determination of suitable pulsed laser parameters needs to be employed in order to achieve these good attributes of PW emission to obtain the final part with high quality. Hence, this work investigates the effects of modifying the pulsed laser parameters on single track formation in AISI 316L pulsed L-PBF using numerical simulation with Flow-3D AM Software. The simulation cases used different pulse durations, duty cycles, and pulse repetition rates (PRR) while the layer thickness, scanning speed and laser power were kept constant. The key results demonstrate that increasing the PRR by four times while maintaining a constant Linear Energy Density (LED) reduced the width of the 700 K isotherm HAZ by 7%, highlighting the role of PRR in minimizing thermal diffusion. Furthermore, increasing the duty cycle while keeping the PRR and pulse period constant resulted in a smoother surface finish, as evidenced by a reduction in surface roughness (Ra) to less than 4 µm, compared to typical Ra values of 5–12 µm in CW L-PBF systems. This change also resulted in a wider HAZ, emphasizing the trade-off between surface finish and thermal diffusion. The findings from this study provide insights for optimizing processing parameters in L-PBF with PW emission, enabling the production of parts with finer geometries and enhanced surface quality.

Ferromagnetic Biochar Derived from Agricultural Waste of Musa acuminata for Adsorption of Dyes

Mon, 20 Oct 2025 00:00:00 +0700

Dyes used in different industries are one of the main sources of water pollution. In this study, ferromagnetic biochar derived from agricultural residues of Musa acuminata was investigated as an adsorbent of dyes from water contaminated with methylene blue and rhodamine b. Biochar was obtained by pyrolysis at 550 °C for 1 h and then subjected to surface modification with FeSO₄. Morphology and surface structure were observed by scanning electron microscopy (SEM) with energy-dispersive X-ray spectroscopy (EDS). Functional groups before and after surface modification were determined using Fourier transform infrared (FTIR) spectra and Raman microscopy. Adsorption experiments were conducted in aqueous solutions previously contaminated with dyes. FTIR and Raman analyses were performed after sorption of the dyes. Adsorption kinetic analyses were performed using pseudo-first-order and pseudo-second-order models along with Intra-particle diffusion analysis. SEM-EDS revealed the biochar porosity and evidenced the presence of Fe in the material structure. FTIR and Raman analysis displayed bands associated with the surface modification with Fe. In the adsorption experiment, a maximum removal of methylene blue of 99.44% and rhodamine b of 98.20% was obtained. FTIR and Raman showed bands associated with dye adsorption. The second-order model described the adsorption kinetics. The ferromagnetic biochar from Musa acuminata demonstrated effective dye adsorption and could be considered an economical and environmentally friendly solution for water decontamination.

Genetic Diversity of Hemp Germplasm in Northern Thailand

Mon, 20 Oct 2025 00:00:00 +0700

Cannabis sativa L., commonly known as hemp, is a plant native to Central Asia. It is well known for its cannabinoid compounds, which have significant potential for medical applications. Recognizing the economic and medical value of hemp, the Thai government has permitted its cultivation for commercial, medical, and research purposes. However, a comprehensive understanding of hemp genetics is crucial to support industry expansion and enhance future breeding programs. This study investigated the genetic diversity of 37 hemp accessions collected in northern Thailand, along with two reference varieties (RPF1 and RPF2). Using DArTSeq-based genotyping-by-sequencing and whole-genome sequencing technologies, we identified 3,609 single nucleotide polymorphisms (SNPs). STRUCTURE analysis, principal component analysis (PCA), and neighbor-joining analysis consistently identified three genetic clusters; however, these clusters did not correlate with geographical locations. Genetic differentiation among clusters was observed (fixation index, F_ST = 0.064-0.079; Nei’s coefficient of genetic differentiation, Nei’s G_ST = 0.058-0.078). Total genetic diversity estimated (expected heterozygosity, H_E = 0.348; observed heterozygosity, H_O = 0.092). Global inbreeding (F_IT = 0.033) and molecular variance (4.83%) suggested low to moderate genetic differentiation, while the high inbreeding coefficient (F_IS = 0.737) indicated substantial inbreeding within clusters. The genetic data from this study provide a resource for developing molecular markers to distinguish hemp varieties, supporting selective breeding efforts. These findings will contribute to improving agronomic traits, conserving genetic diversity, and ensuring the sustainable use of hemp genetic resources.

Impact of Sisal Fiber Reinforcement on the Mechanical and Physical Properties of One-Part Geopolymer Mortar with a Ternary Binder System

Mon, 20 Oct 2025 00:00:00 +0700

This study investigates the influence of chemical treatment and fiber content on the mechanical and durability properties of sisal fiber-reinforced one-part geopolymer mortar (OP-GPM) incorporating a ternary binder system of diatomite, feldspar, and ground granulated blast furnace slag (GGBS). Sisal fibers were treated with 0.5%, 5%, and 10% NaOH solutions for 2 and 24 h and incorporated at 0.5–2% by binder weight. The workability, compressive strength (CS), flexural strength (FS), split tensile strength (STS), ultrasonic pulse velocity (UPV), water absorption, and chemical resistance were evaluated. Optimal performance was achieved with 1% fiber content and fibers treated with 5% NaOH for 2 h, leading to a 15% increase in CS (54 MPa) and notable improvements in FS (8.62 MPa) and STS (5.88 MPa). Alkali treatment significantly enhanced fiber crystallinity and tensile strength, with a 208% reduction in fiber water absorption. However, excessive fiber content (>1%) reduced workability and mechanical performance. Regression analysis showed strong correlations between the strength properties. The study confirms that properly treated sisal fibers improve the mechanical and durability performance of OP-GPM, offering a sustainable alternative to conventional reinforcement in geopolymer composites.

Investigation of the Effects of Unbalance and Bearing Wear on Shaft Vibration in a Natural Gas Turbine Plant

Mon, 20 Oct 2025 00:00:00 +0700

This work investigates the effect of imbalance and bearing wear on the vibration of rotating shafts at a southern Iraqi natural gas liquefaction plant. This experimental study examines the impact of wear on couplings and uneven weight on the vibration of a two-stage gas turbine’s shaft, taking measurements during operation. The experimental procedure involves the use of proximity probes and the ADRE-408 Bentley Nevada system to measure vibrations along the X and Y axes. The study focuses on a two-stage gas turbine supported by four journal bearings and analyses the effects of coupling imbalance and erosion. The results show that adding 10 g and 20 g weights at 0° and 30° anticlockwise considerably increases the vibration amplitude, from 22.46 µm at 113.75 Hz to 24.35 µm at 117.5 Hz. Replacing worn couplings and bearings led to system stabilisation, vibration reductions, and a shift in critical frequencies. The data confirm that mass loss and bearing wear greatly affect the dynamics of rotating machinery. These findings emphasise the importance of predictive maintenance and diagnostic monitoring to prevent mechanical failures and maintain system stability.

Optimizing Methyl Orange Degradation via Electro-Fenton with Copper Foam Cathode: A Comparative Approach Using Iron Waste vs. Iron Salts and Exploring Catalyst and Cathode Durability

Zahraa Majeed Hameed, Rasha Habeeb Salman — Mon, 20 Oct 2025 00:00:00 +0700

The use of foam electrodes as a cathode has proven its efficiency in wastewater treatment. In this study, methyl orange (MO) was treated by Electro-Fenton technology (EFT) using a copper foam (Cf) as a cathode. EFT was an advanced strategy for MO degradation, which accomplished excellent degradation efficiency (%Re_MO) exceeded 98% over 35 min treatment period at prime conditions using 0.124 mM of iron salts (FeSO₄.7H₂O), 0.3 LPM of air flow, 0.2 mA/cm² of current density (CD), and initial pH of 3.0. The outcomes showed that the air flow rate had the main impact on the %Re_MO. Furthermore, the contribution of anodic oxidation (AO) to dye removal was investigated to distinguish its role relative to the EFT mechanism, revealing that the MO degradation was government by EFT. Additionally, iron waste (IW) demonstrated high efficacy as a heterogeneous electro-Fenton catalyst, with both the IW and Cf cathode exhibiting excellent reusability and stability. These findings highlight the potential for integrating sustainable materials and processes in dye removal applications, advancing both efficiency and cost-effectiveness.

Pectin-based Hydrogels Produced from Banana and Mango Peels as a Potential Approach to Removing Heavy Metal Ions from Contaminated Water

Mon, 20 Oct 2025 00:00:00 +0700

The release of harmful compounds from manufacturing processes into the environment causes a variety of environmental problems. In the low concentration range, conventional removal methods are frequently either too costly or insufficiently successful. On the other hand, hydrogel-based biosorption demonstrated to be economical and effective. Biohydrogels suitable to adsorb heavy metal contaminants from water were prepared using pectin obtained from a mixture of banana and mango peels and combined with carboxymethyl cellulose using calcium chloride as a crosslinker. The hydrogel’s internal structure and surface morphology as well as their swelling behavior, swelling-shrinking cycles, and water adsorption capacity under different external pressures were evaluated. The adsorption capacity and the influence of pH and temperature were assessed using Pb(II), Cu(II), Cd(II), and Ni(II). The reusability was investigated by adsorption-desorption cycles. The findings demonstrated a porous structure, more than 80% swelling at pH higher than 5 and within 30 min in contact with the medium, and the capacity to retain water at pressures of up to 400 kPa. With a reusability of five adsorption-desorption cycles, and the ability to adsorb more than 70 mg of each heavy metal ion per gram of dried hydrogel in the resulting order; Cu(II)>Pb(II)>Cd(II)>Ni(II).

Polydimethylsiloxane Based Flexible Antenna with Enhanced Performance and High-Efficiency for Biomedical Applications

Deepthy Grace Sudarsanan, Nesasudha Moses, Karthikeyan Thavittupalayam Angappan — Mon, 20 Oct 2025 00:00:00 +0700

PDMS is frequently utilized in the biomedical field because of its biocompatibility. The PDMS finds applications in medical implants, cardiovascular flow replication, and in the biomedical industry. This paper presents an innovative antenna design optimized for biomedical applications operating in the Industrial, Scientific, and Medical (ISM) band (2.4–2.5 GHz). The proposed antenna features a compact, flexible structure utilizing a Polydimethylsiloxane (PDMS) substrate to prioritize patient safety and comfort. For PDMS, the loss tangent is 0.0134 and the dielectric constant is 2.71. The design process employs parametric optimization to achieve a low-profile configuration with a wide impedance bandwidth and better radiation characteristics. Simulations and experimental validation using a multi-layered tissue phantom demonstrate superior performance, achieving a return loss below -10 dB across the ISM band. Additionally, Specific Absorption Rate (SAR) measurements confirm compliance with international safety standards, ensuring minimal electromagnetic exposure. PDMS-based flexible antennas hold promise for biomedical applications, but many existing designs face challenges related to limited gain, narrow bandwidth, and poor mechanical stability under continuous body movement. This highlights the need for more reliable and adaptable antenna solutions for on-body use. This study underscores the potential of the proposed ISM-band antenna to enhance the functionality and efficiency of biomedical communication systems, driving advancements in telemedicine and personalized healthcare solutions.

Role of Activated Carbon from Arabica Coffee Waste in Enhancing the Dehydrogenation Properties of Magnesium Hydride (MgH2) for Hydrogen Storage

Mon, 20 Oct 2025 00:00:00 +0700

Solid-state hydrogen storage requires improvement through catalyst-added methods to maximize performance. Magnesium Hydride (MgH₂) is a type of solid-state hydrogen storage that is highly developed today but has many shortcomings, including high dehydrogenation temperatures. The use of carbon-based catalysts derived from biomass offers dual advantages by harnessing agricultural waste and supporting environmentally sustainable practices. This study utilized activated carbon (AC) from Arabica coffee agroindustry waste, specifically from pulp and parchment, as a catalyst to enhance the properties of MgH₂. The activated carbons from coffee pulp and parchment (ACs) were produced through slow pyrolysis at 400 °C and chemically activated using potassium hydroxide (KOH) and sodium hydroxide (NaOH) solutions at various concentrations. Composites of MgH₂ + 5 wt% AC were prepared through three hours of intensive mechanical alloying. Initially, the ACs were characterized using iodine adsorption, FTIR, TGA-DSC, and SEM analyses. The MgH₂ + 5 wt% AC composites were then subjected to characterization through XRD, TGA-DTA, and SEM analysis. The results of the thermal investigations indicated that the AC catalysts from coffee pulp and parchment significantly reduced the onset temperature of dehydrogenation for MgH₂. The lowest dehydrogenation temperature was 342.36 °C, achieved by adding 5 wt% AC produced from coffee parchment that was chemically activated using a 2% KOH solutions.

Role of Tin Metal in Red Visible Light in Diesel Oil Desulfurization Process with Looping Process System

Dino Dewantara, Ismail, Muhammad Djoni Bustan, Sri Haryati — Mon, 20 Oct 2025 00:00:00 +0700

The conventional desulfurization process requires a considerable quantity of materials. It presents a significant challenge to control, both of which contribute to a higher cost of production for low-sulfur diesel fuel. The utilization of red visible light, a clean and environmentally health-friendly form of energy and can be employed under low operating conditions, represents an adequate substitute for the promising diesel oil desulfurization process. The potential of metallic catalysts to enhance the properties of red visible light in the desulfurization process was investigated. The red visible light desulfurization process demonstrated that diesel oil can be reduced in sulfur content under ambient operating conditions. The highest yield in this study was achieved at a catalyst height variation of 6 cm and an irradiation time of 25 h with a sulfur content of 737 ppm. Tin metal significantly enhances red visible light's photon energy, frequency, wavelength, and minimum kinetic energy.

S-Scheme ZnO/g-C3N5 Visible Light Active Photocatalyst for Rhodamine B Dye Degradation and Hg Sensing Applications

Mon, 20 Oct 2025 00:00:00 +0700

The main focus of the current work, the host material (ZnO and g-C₃N₅ NPs) and its composites (ZnO/g-C₃N₅) were synthesized by precipitation and hydrothermal methods using zinc nitrate and melamine. The final materials were exposed to photocatalytic and electrochemical activities after being thoroughly characterized by PXRD, UV-visible DRS Spectroscopy, FT-IR, XPS, SEM-EDS, and TEM. There are diffraction peaks in the PXRD pattern that belong to both the ZnO and g-C₃N₅ samples. The estimated band gap energy decreases from 3.08 (ZnO) to 2.74 ZnO/g-C₃N₅ eV. The ZnO/g-C₃N₅ shows enhanced photocatalytic activity of 97.53% for degradation of RhB dye in visible light irradiation. Further, the ZnO/g-C₃N₅ composite material is a selective modifier pattern for mercury detection. This synthesized material shows better sensitivity at the lowest detection limit of 1nM. Hence, this work shows the novel synthesis for the effective photocatalyst for water treatment and as an efficient sensor for the detection of mercury levels in the wastewater.

Sustainable Production of Vanillin from Vanillyl Alcohol, a Model Compound of Lignocellulosic Biomass Conversion, via Selective Heterogeneous Catalysis

Mon, 20 Oct 2025 00:00:00 +0700

Vanillin, a flavoring agent, is used extensively in the food industry. It is primarily derived from a petroleum derivative through synthetic procedures, though these technologies present certain drawbacks, including the generation of undesired byproducts and a relatively low yield. Furthermore, residual lignocellulosic biomass serves as a renewable source of aromatic compounds with the potential to be used as raw material in the synthesis of vanillin. This would allow the valorization of the residue, resulting in the production of a highly demanded compound for the food industry. To achieve this objective, a heterogeneous Pd catalyst supported on alumina was prepared and its activity was investigated in the oxidation reaction of vanillyl alcohol, a model compound of lignin, to obtain vanillin. The impact of key reaction parameters, including temperature, oxidant concentration, pH of the medium, and solvent, was evaluated. The Pd(1%)/Al₂O₃ catalyst used was capable of achieving 84% conversion and selectivity over 99% towards vanillin under mild conditions after a 3-hour reaction period in an alkaline medium using water as a solvent.

Synthesis and Characterization of BiVO4/S,N-CQDs as Photoelectrochemical Water Splitting Material

Mon, 20 Oct 2025 00:00:00 +0700

Hydrogen has emerged as a promising renewable energy source to replace fossil fuels, driving the need for efficient and low-emission hydrogen production methods. Among these, photoelectrochemical (PEC) water splitting using solar energy and semiconducting materials as photoanodes holds significant potential. This study focuses on enhancing the performance of bismuth vanadate (BiVO₄), a highly promising photoanode material, synthesized on fluorine-doped tin oxide (FTO) substrates via a hydrothermal method. This research aims to improve the efficiency and stability of BiVO₄ as a photoelectrochemical anode material by integrating sulfur-nitrogen-doped carbon quantum dots (S,N-CQDs), derived from Egeria densa algae, to minimize charge recombination and enhance light absorption as well as the efficiency of solar energy conversion to hydrogen. To address the challenge of charge recombination, S,N-CQDs were integrated into BiVO₄ using a spray-coating method in varying volumes (0, 2.5, 5, 7.5, and 10 mL). The incorporation of S,N-CQDs significantly reduced the band gap of BiVO₄, with the most notable reduction at 7.5 mL (from 3.14 eV to 2.70 eV). This modification resulted in enhanced PEC water splitting performance, with a maximum photocurrent density of 0.0698 mA/cm² and a photoconversion efficiency of 0.0131%. Additionally, the optimized BiVO₄/S,N-CQDs photoanode exhibited a double-layer capacitance (Cdl) of 0.102 mF/cm², indicating improved charge transport properties. These results demonstrate that the integration of S,N-CQDs into BiVO₄ not only enhances PEC efficiency but also contributes to the development of cost-effective, sustainable solutions for solar-driven hydrogen production, supporting the transition to a renewable energy future.

Synthesis and Characterization of Nano Active Filler of Pumice Particle Produced by Sol-Gel Process with Different Precipitation Temperatures for Enhancing the Impact Properties of GFRP Composite

Mon, 20 Oct 2025 00:00:00 +0700

Pumice, a volcanic mineral abundant in Indonesia that can contain up to 70% silica, is a great source of nanosilica material. The mesoporous amorphous nanosilica, called nano active filler of pumice particle (nAFPP), has been successfully synthesized using a sol-gel process with different precipitation temperatures at 45, 55, and 65 °C. The nAFPP was characterized using SEM-EDX, Multi-Point BET, and BJH techniques for surface properties and morphologies studies, FTIR for chemical bond studies, XRD for crystallinity properties, and TGA/DTA characterization for thermal stability studies. The influence of nanosilica filler in forming GFRP/nAFPP composites was evaluated using impact testing and morphological analysis with SEM on the fracture surfaces. The result shows that the nanosilica of nAFPP has good purity (93.68%), mesoporous amorphous, nano-sized silica particles, and a pore diameter of 4.36–6.97 nm. The spectra of FTIR display the absorption peaks of the functional group silanol (Si-O-Si). The GFRP/nAFPP composites have higher impact strength than those with pumice particles or without particles. The highest impact strength (97.37 KJ/m²) is achieved in the GFRP composite with 2.5 of nAFPPP, and its addition until 10 decreases the impact strength slightly. Further research on this material is needed to accelerate its application.

Tin Powder Preparation by Electrodeposition of Tin Chloride in a Choline Chloride-Ethylene Glycol Deep Eutectic Solvent

Mon, 20 Oct 2025 00:00:00 +0700

Tin powder is widely used in industry as a raw material for making various products. In this study, the tin powder is prepared by electrodeposition of a mixed solution of tin chloride with a deep eutectic solvent as the electrolyte, to investigate the impact of electrodeposition variables on the current efficiency and the tin morphology produced at the surface of the stainless steel 316 cathode. A cyclic voltammetry test was applied to observe the characteristics of the electrolyte solutions, and the electrodeposition experiment was applied to investigate the impact of technological variables on current efficiency and tin morphology formed at the stainless 316 cathode surface. Experimental findings show that in the cyclic voltammetry test, increasing the tin amounts in electrolyte solutions from 5 to 30 g L⁻¹increased the cathodic peak current, and the higher tin amount creates a higher current density. While in the electrodeposition process, the cathode current efficiency increased when the electrodeposition current was raised from 2.5 to 6.88 A dm⁻² or the tin amounts in the electrolyte solution were raised from 5 to 10 g L⁻¹. Additionally, smaller tin particles were produced at a higher current density, lower temperature, and lower tin amount.