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This study aims to analyze the development of studies on the use of biomass as a renewable energy source to support national energy security using a bibliometric approach. Research data were obtained from the Scopus, Web of Science, and Google Scholar databases with a publication range of 2015-2025. The analysis was conducted using VOSviewer and Biblioshiny. The results show a significant increase in publication trends in the last decade, especially in the period 2016-2024, reflecting the increasing academic attention to biomass as a solution in the energy transition. Keyword visualization shows that biomass is closely related to concepts such as combustion, thermal efficiency, calorific value, and pelletizing. China is the country with the highest publication contribution, while Indonesia is strategically positioned due to its abundant biomass waste potential. Overall, biomass has great potential to support energy diversification, reduce dependence on fossil fuels, and strengthen national energy security in a sustainable manner.

The low thermal efficiency of Gas Power Plants (PLTG) due to exhaust gas heat loss drives the implementation of cogeneration at PLTGU Block II PT. PLN Indonesia Power UBP Semarang. This study analyzes the performance of the Gas Turbine Generator (GTG), combined cycle efficiency, and Exergy distribution using a 3-3-1 configuration. The research utilizes actual operational data from January 28, 2026, sampled at 10-minute intervals. Results indicate that cogeneration via a Heat Recovery Steam Generator (HRSG) significantly enhances plant efficiency. The GTG output ranged from 273–283 MW with an efficiency of 30.0–30.2%. Following combined cycle integration, system efficiency increased to 43.9–44.4%, a gain of approximately 14%, with a heat rate of 11,916–11,988 kJ/kWh. Exhaust heat of 665–713 MW was recovered to generate an additional 130 MW through the Steam Turbine Generator (STG). Exergy analysis reveals that the largest irreversibility occurs in the GTG combustion process (285 MW), followed by the HRSG (185 MW) and STG (49 MW).

This study was motivated by students’ low conceptual understanding of temperature, heat, and thermal expansion at SMP Negeri 28 Batanghari, where learning achievement remained below 50%. Instruction predominantly used PowerPoint-based media, resulting in passive learning and limited contextual engagement. This study aimed to develop web-based interactive multimedia (GlidesApps) integrated with Cepak Kapung ethnoscience that is valid, practical, and effective in improving seventh-grade students’ conceptual understanding. The study employed a Research and Development (R&D) approach using a development model consisting of five stages: analysis, design, development, implementation, and evaluation. The resulting product, named LokaSains, is a web-based learning application accessible via smartphone, laptop, or computer without installation. It presents learning content on temperature, heat, and thermal expansion integrated with the ethnoscience of Cepak Kapung, a traditional cake from Batanghari Regency. Content expert validation obtained a score of 91.07% (very valid), while media expert validation reached 87.50% (very feasible) after two revisions. Teacher practicality assessment produced 98.33% (very practical), and student responses in small-group and large-group trials reached 94% and 90.35%, respectively (very good). During implementation with 28 seventh-grade students, the mean pretest score increased from 46.07 to 76.79 in the posttest. A paired samples t-test produced t = −13.053 with Sig. (2-tailed) = 0.000 < 0.05, indicating a significant difference in conceptual understanding before and after using the multimedia. The N-Gain score of 0.57 indicated moderate effectiveness in improving learning outcomes. Accordingly, the LokaSains interactive multimedia is considered valid, highly practical, and effective for teaching temperature, heat, and thermal expansion at junior high school level.

Natural fiber based composite materials are increasingly being developed as an environmentally friendly alternative to synthetic fiber-based composites. This study aims to characterize the thermal and mechanical properties of natural fiber composite materials and evaluate their potential use as sustainable materials. Composites are made using natural fibers as reinforcement and a polymer matrix through a specific molding method. Mechanical property characterization includes tensile tests, flexural tests, and impact tests, while thermal property characterization is carried out using thermal analysis to determine the thermal stability of the material. The test results show that the addition of natural fibers has a significant effect on improving the mechanical properties of the composite, especially tensile strength and elastic modulus, compared to the unreinforced matrix. In addition, natural fiber composites show quite good thermal stability over a certain temperature range, making them suitable for non-structural applications. Based on these results, natural fiber composite materials have the potential to be developed as environmentally friendly materials that have competitive mechanical and thermal performance.

This research investigates intelligent cooling system design for main ship engines operating in tropical waters, integrating advanced machinery engineering with human factors to address thermal management challenges affecting engine performance, reliability, and crew operational effectiveness. Tropical maritime environments impose severe cooling demands through elevated seawater temperatures (28-32°C), high ambient conditions (28-35°C), and accelerated biofouling, reducing conventional cooling system effectiveness by 15-25% while increasing maintenance burdens and operational risks. Through qualitative analysis involving marine engineers, chief engineers with tropical operational experience, cooling system manufacturers, naval architects, automation specialists, and maritime training institutions, this study examines how intelligent cooling systems incorporating variable-speed pumps, adaptive control algorithms, predictive maintenance, and crew-centered interfaces can optimize thermal management while supporting effective human-machine collaboration. Results demonstrate that intelligent systems can reduce cooling energy consumption by 20-35%, improve temperature stability by 50-65%, extend maintenance intervals by 40-80%, and enhance crew situational awareness through intuitive monitoring interfaces, while requiring comprehensive training programs developing technical understanding and operational competencies. Key implementation challenges include control system complexity, sensor reliability in harsh marine environments, integration with existing engine management platforms, crew competency development requirements, and lifecycle cost justification. Findings reveal that successful intelligent cooling system implementation requires holistic sociotechnical approach addressing machinery engineering optimization, automation technology deployment, and human capability development through coordinated design and training strategies. This research contributes to marine engineering literature by providing integrated frameworks for intelligent system design incorporating machinery performance, automation capabilities, and human factors supporting operational excellence in tropical maritime operations.

This research investigates thermal material properties and performance characteristics for high-speed vessel components subjected to extreme thermal stress during sustained high-speed operations. High-speed vessels including patrol boats, fast ferries, and naval craft experience elevated thermal loads from high-power density propulsion systems, aerodynamic heating, and sustained operational intensities creating demanding conditions for structural and mechanical components. Through qualitative analysis involving naval architects, materials engineers, high-speed vessel operators, and component manufacturers, this study examines how material thermal properties affect component durability, performance, and safety while identifying optimal material selections for critical applications. Results demonstrate that advanced thermal materials including high-temperature aluminum alloys, titanium alloys, ceramic composites, and thermal barrier coatings can extend component service life by 40-70%, improve thermal management effectiveness by 25-45%, and enhance operational reliability compared to conventional materials. Key implementation challenges include material cost premiums of 150-300%, manufacturing complexity, limited operating experience, qualification testing requirements, and supply chain constraints. Findings reveal that strategic thermal material selection for critical components represents essential enabling technology for high-speed vessel performance, reliability, and operational availability supporting defense, commercial, and emergency response applications requiring sustained high-speed capabilities. This research contributes to marine materials engineering literature by providing evidence-based frameworks for thermal material selection applicable to diverse high-speed vessel applications.

Plastic waste has become one of the main environmental problems due to its nature, which is difficult to decompose naturally and can cause environmental pollution. One alternative waste treatment method that can be applied is to use a plastic melter to melt and recycle plastic waste into useful products. However, the design of plastic melters often lacks consideration of structural strength and safety aspects during the operation process. This study aims to design and engineer a plastic melter using the Finite Element Analysis (FEA) simulation approach to analyze structural resistance to thermal and mechanical loads that occur during the operation process. The research method was carried out through 3D design modeling of plastic melter components using Solidworks software, followed by analysis with FEA simulation on the main component, namely the melting tube. The parameters analyzed include the distribution of von Mises stress, the amount of displacement, and the safety factor. The analysis results show that the analyzed components experience von Mises stress distribution and displacement that are still below the material tolerance limits, with safety factor values above the recommended safety limits. Thus, the resulting plastic melter design is declared safe and can proceed to the manufacturing process. Therefore, the plastic melter design is safe, strong, and feasible to be realized as an effective and sustainable plastic waste processing technology solution.

The global energy crisis and climate change are driving the development of biodiesel as a renewable energy source. Graphite as an additive shows significant potential in improving the efficiency and reducing emissions of biodiesel. This study maps graphite-biodiesel research in Southeast Asia using a meta analysis of systematic reviews of 68 publications from Scopus, Web of Science, and ScienceDirect from 2015-2024. The results show that Malaysia leads in publication contributions (32%), followed by Thailand (28%) and Indonesia (18%). The optimal graphite concentration of 50 ppm increases brake thermal efficiency by 8.3% and reduces CO (15.7%), HC (12.4%), and smoke (18.9%) emissions, although there is an increase in NOx (6.8%). Palm oil methyl ester dominated the research (56%). Indonesia has strategic opportunities with abundant feedstock and graphite deposits, but faces challenges in research infrastructure, limited international collaboration, and the absence of an integrated national roadmap. Infrastructure investment, human resource strengthening, and industry academia collaboration are needed to accelerate national biodiesel research.

The increasing need for insulation in electric power systems encourages the discovery of high-performance and sustainable dielectric materials. This study presents a Literature Review of biomass-based composite insulator research from 2018-2025 to synthesize the effect of filler type and treatment on the electrical, thermal, and mechanical properties of polymer composites. Literature was analyzed from reputable databases with inclusion criteria, and thematic analysis data extraction. Processing methods generally include washing, acid/alkali treatment, calcination, and advanced production techniques such as sol-gel and ultrasonication, integration of biomass fillers especially at low fractions (3-7%). The results show 1) the dominance of the use of rice husk as a source of biosilica for the main matrix filler of the insulator. 2) the performance of biomass composite insulators is highly dependent on the quality of purification, particle size, and surface modification of the filler. 3) there is a significant increase in the insulator's breakdown strength, resistivity, and thermal stability with the addition of biomass fillers to the main matrix. 4) the long-term stability of biomass materials against humidity and thermal aging has not been evaluated in depth.  

Steam turbines remain a core technology in thermal power generation and continue to evolve through advances in aerothermal design, materials, control strategies, and digital maintenance. This paper presents a systematic literature review (SLR) of recent international studies published between 2020 and 2025 to synthesize current developments in steam turbine performance and thermal efficiency improvement. Article identification was conducted through SCOPUS using keywords related to turbine efficiency, blade/nozzle optimization, failure analysis, and material enhancement. The selected studies were analyzed thematically across four domains: (1) design and optimization using CFD/FEA, (2) material and structural resilience, (3) operational performance under variable/part-load conditions, and (4) integration with hybrid renewable systems and predictive maintenance. The reviewed evidence indicates that CFD-based nozzle/blade optimization and advanced control approaches can yield measurable efficiency improvements (approximately 2–7.3%), while material innovations and enhanced cooling strategies improve durability by mitigating thermal stress and fatigue risks. In parallel, digitalization through IoT-based predictive maintenance and additive manufacturing is increasingly reported as a pathway to reduce downtime and accelerate component production. However, recurring gaps include limited real-world validation, insufficient studies in humid/tropical environments, and a lack of long-term economic/lifecycle assessments. Future work should prioritize experimental or field verification, region-specific performance studies, and integrated techno-economic evaluation to support broader deployment of high-efficiency steam turbine systems.

Cooling towers are widely used in various industrial applications for water cooling systems. In these towers, water is cooled by air, and the heat released from the water to the air consists of both sensible and latent heat. The efficiency of this heat transfer significantly impacts the performance of the cooling tower. Objective: This study aims to determine the effectiveness and mass flow rate of water in a cooling tower, focusing on the relationship between water temperature, flow rates, and overall cooling tower performance. Method: The analysis includes measurement of the water temperature (48.176 °C), mass flow rate (175.235 kg/s), and the wet bulb temperature (16.988 °C) in the cooling tower. These parameters are analyzed to assess the cooling tower's performance in terms of its heat transfer efficiency. Results: The cooling tower's performance analysis shows an effectiveness of 59.36%. The mass flow rate of water is 175.235 kg/s, and the hot water flow rate is 9373.32 kg/s. The data indicate that the improved water flow and air flow have a positive impact on the heat transfer rate. Novelty: This study highlights the critical role of maintenance and the optimization of flow rates and cooling tower components in enhancing the heat transfer efficiency. It offers valuable insights into the relationship between operational parameters and cooling tower performance. Implications: The findings suggest that proper maintenance and improvements to water and air flow can significantly enhance cooling tower efficiency, leading to better heat transfer and overall system performance. This has important implications for industrial applications that rely on cooling towers for effective water cooling systems.

This study aims to analyze the comparison of the durability of natural fiber and synthetic fiber composites in a high-temperature production environment. Testing was conducted on carbon fiber, aramid (synthetic), ramie, and jute (natural) fiber-based composites with exposure to temperatures of 80-150°C for 500 hours. The parameters measured include tensile strength, elastic modulus, dimensional stability, morphological changes, and moisture absorption. The research results show that synthetic fiber composites have superior durability compared to natural fibers. Carbon fiber composites retain 87% of their initial tensile strength with only a 4.2% reduction in modulus, while flax fibers only retain 62% strength with a 26% reduction in modulus. Microscopic analysis revealed significant delamination in natural fiber composites with interface gaps of 15-25 μm, compared to 3-5 μm in synthetic fibers. Natural fibers undergo thermal degradation due to the decomposition of lignin and hemicellulose, resulting in significant color changes and a dimensional shrinkage of 3.2%. The moisture absorption of natural fibers increases to 8.5% after exposure, indicating damage to the cellular structure. This research concludes that synthetic fiber composites are more suitable for long-term high-temperature production applications, but natural fibers can still be considered for low-temperature applications with appropriate chemical modification.

This study comprehensively evaluates the quality of biomass briquettes produced from blends of coconut shell charcoal and sengon sawdust, using both carbonized and non-carbonized materials. Composite briquettes were fabricated with varying compositions and characterized through proximate analysis, calorific value, density, and burning rate measurements to determine their suitability as solid fuel. The results indicate that adding non-carbonized sawdust increases volatile matter content and burning rate but reduces the calorific value of the briquettes. In contrast, incorporating up to 10% carbonized sawdust significantly improves the calorific value to 6119.2 cal/g, approaching that of pure coconut shell charcoal (6352.2 cal/g), while maintaining a relatively high burning rate. Briquettes containing carbonized sawdust also exhibit low ash content, below 3%, and moisture content under 8%, meeting standard solid fuel quality requirements. These findings demonstrate that a strategic combination of carbonized and non-carbonized materials can produce hybrid biomass briquettes with optimized thermal performance, providing a promising, sustainable, and environmentally friendly alternative fuel for domestic and industrial applications.

Natural fibers continue to attract the interest of researchers to develop them as composite reinforcements in automotive and non-construction building interior applications. Basically, natural fiber-reinforced polymer composites are not suitable for applications exposed to heat. Investigating changes in mechanical properties due to temperature increases, this research is very important to conduct. The addition of filler (CaCO3) is known to improve the performance of natural fiber-reinforced polymer composites. This study investigates the physical, mechanical, and thermal properties of polyester composites reinforced with waru fibers with CaCO3 powder filler. The composites were fabricated using the hand lay-up method with a volume fraction of 30% waru fibers and CaCO3 powder with a volume fraction of 0-10%. The density of the polyester composite increased from 1.42 to 1.68 and 1.87 g/cm3 as the volume fraction CaCO3 0-10%. The results of dynamic mechanical analysis (DMA) testing of the polyester composite showed that parameters such as loss modulus, storage modulus, and tan delta also increased with increasing CaCO3 content. Thermogravimetric analysis (TGA) testing also showed increased thermal resistance after the addition of 5% (wt) (STL) and 10% (wt) (ZMB) with a residual combustion of 6.54% and 7.89% for each STL and ZMB composite, respectively. Compared to the TKO composite, it had the lowest combustion residue of 3.61%. Tensile strength and elastic modulus showed the same trend, namely an increase, while the elongation of the composite decreased with the addition of CaCO3 powder. The overall test results showed that polyester composites reinforced with CWf fibers and CaCO3 fillers were suitable for automotive and building interior applications.

This study aims to compare the thermal efficiency of two aluminum and iron-based pans in the water heating process. This research method uses a mixed approach that includes direct observation (qualitative) and quantitative analysis based on changes in water temperature after heating at two volume variations, namely 0.25 L and 0.5 L. Heating was carried out with two time differences, the total of each experiment was four experiments, with two experiments for five minutes and also two experiments for ten minutes. The results showed that iron pans produced heat of 66,150 J at a volume of 0.25 L and 151,200 J at a volume of 0.5 L. Meanwhile, an aluminum pan could produce heat of 53,550 J at a volume of 0.25 L and 67,200 J at a volume of 0.5 L. The difference in heat value was influenced by the thermal conductivity and physical characteristics of each material. This study provides an understanding of the thermal performance of both pot materials and can be considered in the selection of efficient cooking utensils in the household environment.

This study formulates a design concept for the Beach Tourism Resort Area in Botubarani Village by applying tropical architecture that responds to coastal climatic conditions while enhancing the quality of visitor experiences. The research integrates principles of thermal comfort, environmental sustainability, and the ecological potential of coastal environments as the basis for creating climate-adaptive and environmentally responsive tourism areas. The methodology includes site analysis, field observation, climatological assessment, and a literature review related to tropical architecture and coastal tourism design. The collected data were used to determine building orientation, mass layout patterns, visitor capacity, materials, vegetation, and utility systems appropriate for humid tropical climates. The findings show that the site’s position between the sea and the mountains, combined with full-day sun exposure, requires design strategies that maximize cross-ventilation, utilize sloped roofs, provide natural shading, and apply local materials such as wood, bamboo, and red brick. The large spatial needs based on visitor capacity projections are accommodated through a flexible cluster layout that supports visual and functional connectivity between buildings while incorporating green open spaces to enhance microclimate comfort. The utility system is designed using sustainability principles through greywater–blackwater separation, infiltration wells, and recycling-based waste management. This study confirms that the application of tropical architecture in coastal tourism areas can improve thermal comfort, energy efficiency, and environmental sustainability. These findings guide developing tropical tourism area designs that are more adaptive to climate change and more responsive to visitor needs.

Salah satu bentuk pengolahan limbah menjadi energi yang berasal dari limbah padat perkotaan adalah sampah bahan bakar turunan atau Refuse Derived Fuel (RDF). Terdapat berbagai teknologi pengeringan yang biasanya digunakan untuk pengeringan RDF. Contoh penerapannya adalah oil tube rotary dryer sebagai alternatif dari steam tube rotary dryer karena sejumlah alasan utama. Pertama, penggunaan oil engine sebagai material penghantar panas tidak membutuhkan tekanan tinggi seperti pada steam tube rotary dryer sehingga komposisi desain yang tidak serumit steam tube rotary dryer. Penelitian ini dilakukan untuk mengetahui perancangan dan analisis kekuatan struktur mesin oil tube rotary dryer yang dilakukan melalui software Solidworks. Cara kerja mesin dimulai dari pemanasan thermal oil di unit pemanas hingga mencapai suhu operasi yang diinginkan. Oil panas kemudian disirkulasikan secara tertutup ke dalam tube di dalam drum pengering. Pada saat yang sama, RDF dengan kadar air awal 55% dimasukkan melalui inlet housing ke dalam shell. Suhu yang bekerja pada oil untuk memanaskan sekitar 150°C, jumlah total tube 65 buah berdiameter 1,25 inch, dan panjang pipa 10 m yang tersusun di dalam shell. Hasil analisis struktur mesin oil tube rotary dryer berdasarkan simulasi didapatkan stress (von mises) dengan nilai tertinggi 9,371 × 108 N/m^2. Sedangkan nilai terendah 9,628 × 103 N/m^2. Nilai tertinggi dari hasil simulasi tersebut terjadi pada sudut tajam bagian support roller yang tidak terdapat kontak, sehingga hal ini dapat diabaikan karena merupakan stress singularity. Hasil simulasi displacement  dengan  nilai tertinggi 1,026 × 101 N/m^2. Sedangkan nilai terendah 1,000 × 10-30 N/m^2. Nilai tertinggi dari hasil simulasi tersebut merupakan penerapan dari gaya centrifugal yang terjadi pada drum/shell rotary. Hasil simulasi Safety factor yaitu mengacu pada rata-rata probe result adalah 2,3. Sehingga dari hasil simula

Disc discs are the main component in a motorcycle braking system that functions to convert kinetic energy into heat energy through friction. The geometric design of the disc, including the diameter and number of holes, affects the effectiveness of braking as well as the heat dissipation ability. This study aims to analyze the effect of variations in diameter and number of holes on disc discs on braking distance and disc temperature. The research method used was an experimental method with three variations in disc diameter (190 mm, 220 mm, and 260 mm) and three variations in the number of holes (30, 36, and 42 holes). The test was carried out through a controlled braking procedure at an initial speed of 40 km/h on flat road surfaces with stable weather conditions. Braking distance data is measured using ultrasonic sensors, while disc temperature is recorded with a high-accuracy infrared thermometer. The results showed that the diameter of the disc disc had the most significant influence on the braking distance. The larger the diameter, the greater the braking moment resulting so that the stopping distance becomes shorter. The number of holes in the disc also plays a role in heat dissipation because the holes enlarge the heat dissipation area. However, the increase in the number of holes tends to slightly increase the braking distance due to a reduction in the area of frictional contact field. The most optimal configuration is found on a 260 mm diameter disc with 42 holes, which results in the shortest braking distance of 8.25 meters and the lowest temperature rise of 4.47°C.  Statistical analysis using Two-Way ANOVA confirmed that the diameter and number of holes had a significant effect individually, but there was no significant interaction between the two. These findings confirm that the selection of the right disc dimensions is critical to improving braking performance, thermal efficiency, and rider safety.

This study aims to investigate how variations in the soaking time of Luffa cylindrica fibers in alkaline solutions affect the mechanical properties and fire resistance of the resulting composite material. The use of natural fibers is an important step in finding environmentally friendly and sustainable alternatives to replace synthetic materials. Luffa cylindrica fibers were chosen for their advantages, such as being lightweight, strong, and abundantly available. However, natural fibers like luffa contain non-cellulose compounds, such as lignin and hemicellulose, that can hinder strong bonding with the resin matrix. Therefore, pre-treatment with an alkaline solution is necessary to remove these interfering substances. In this study, composites were made using the hand lay-up method with polyester resin as the main matrix. The treatment variable tested was the fiber soaking time in KOH solution, with three variations: 2 hours, 4 hours, and 6 hours. After the composite fabrication, the samples were tested through several standard tests, including tensile tests to measure the material's strength under tension, impact tests to assess toughness, and burn rate tests to evaluate fire resistance. Additionally, macro and micro photo analysis (using SEM if possible) will be conducted to observe fracture characteristics and the quality of the fiber-resin bond. The expected outcome is that longer alkaline soaking will significantly improve tensile strength and toughness. Furthermore, longer soaking is also expected to improve fire resistance by forming a char layer, which acts as a thermal insulator, slowing heat transfer and reducing the rate of pyrolysis.

This study aims to analyze the thermal performance of the heating system in a small-scale plastic bolt molding machine using LDPE material, in order to determine process parameters that are efficient while maintaining product quality. The method used includes experimental testing at two set-point temperatures (90 °C and 120 °C), measurement of melting time and feed mass per cycle, as well as heat balance calculations separating the contributions of conduction, convection, and radiation on the barrel heated by a band heater. In addition, the power/energy requirement per cycle and productivity projections based on hopper capacity were calculated. The results show that increasing the set-point from 90 °C to 120 °C accelerates melting from ±240 s to ±180 s (≈25% faster). Heat transfer analysis confirmed the dominance of conduction (≈329.7 W at 90 °C and ≈471 W at 120 °C), while convection and radiation contributions were much smaller; the total system heat rate was ≈342.7 W (90 °C) and ≈490.8 W (120 °C). The discussion highlights the process trade-off: higher set-points increase production rate and mold filling quality (due to lower melt viscosity), but may raise energy consumption per cycle and require tighter mold temperature control to limit shrinkage/warpage. The practical implications for SMEs are the need for efficiency strategies based on barrel insulation, heater contact area optimization, and correlation of temperature-time settings with quality and energy consumption targets. This study concludes that controlled temperature and heating duration, supported by simple yet targeted thermal design, can improve cycle time consistency, dimensional precision, and energy efficiency in small-scale plastic bolt molding machines.