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This study aims to design and implement a simple solar panel-based battery charging system equipped with protection and voltage limiting circuits. The study was conducted to address the limitations of a direct solar panel-to-battery connection, which may cause short-circuit risk, reverse current, unstable charging voltage, and excessive battery charging. This research used a design-based experimental approach. The system was developed by preparing a block diagram, dividing it into several functional sub-blocks, and implementing the design into an electronic circuit. The main circuit sections consisted of solar panel protection, voltage limiter, interlocking circuit breaker, power regulator, and voltage divider. The assembled circuit was tested through real-time measurement by observing solar panel output voltage under different time and sky conditions and measuring battery charging time from different initial voltage levels. The results show that the solar panel output voltage varied according to time and weather condition. The lowest measured voltage was 15.0 V under cloudy conditions, while the highest measured voltage was 25.2 V under clear sky conditions around midday. The battery charging test showed that lower initial battery voltage required longer charging time, while voltage closer to the target level required shorter charging time. The evaluation was limited to voltage measurement and charging time; charging current, battery temperature, solar irradiance, and charging efficiency were not measured in detail. The proposed system can be applied for small-scale solar charging, educational practice, and basic renewable energy experiments. The study offers a practical circuit model that integrates protection, interlocking, voltage limiting, and regulation functions using simple and accessible electronic components.

This research investigates the integration of Sound Governance principles within the sustainable tourism policy cycle as a mechanism to mitigate institutional fragmentation and evaluation inefficiencies in developing economies. Adopting a sequential explanatory mixed-methods design, the study establishes a multidimensional evaluation framework congruent with the Sustainable Development Goals (SDGs). Policy performance is rigorously analyzed across five strategic domains: Economy, Social-Welfare, Culture-Education, Environment, and Governance. The quantitative methodology employs 17 adapted SDG indicators to assess policy efficacy, while the subsequent qualitative phase utilizes semi-structured interviews and stakeholder mapping to deconstruct complex power dynamics within multi-actor co-management structures. The empirical findings demonstrate that Sound Governance—predicated on transparency and accountability—acts as a fundamental catalyst for policy effectiveness. It significantly enhances destination sustainability through a structured input-process-output-outcome-impact pathway. Evidence from the case study of Penglipuran Village, Bali, validates these results, showing that while indigenous institutional legitimacy bolsters social responsiveness, it remains susceptible to economic dependencies driven by overtourism. Ultimately, this study asserts that embedding SDGs into the policy evaluation cycle elevates assessments from perfunctory administrative exercises to strategic instruments essential for ecosystem preservation and long-term demand stability. These insights establish Sound Governance as a strategic intangible asset, providing significant theoretical contributions to development administration and offering pragmatic frameworks for policy-makers managing sustainable destinations in competitive global markets.

This study examines the integration of Sound Governance principles within the sustainable tourism policy cycle to address institutional fragmentation and evaluation inefficiencies in developing economies. Using a sequential explanatory mixed-methods design, the research develops a multidimensional evaluation framework aligned with the Sustainable Development Goals (SDGs), analyzing policy performance across five strategic domains: Economy, Social-Welfare, Culture-Education, Environment, and Governance. The quantitative phase utilizes 17 adapted SDG indicators to measure policy efficacy, while the qualitative phase employs semi-structured interviews and stakeholder mapping to deconstruct power dynamics in multi-actor co-management structures. The findings reveal that Sound Governance—specifically transparency and accountability—serves as a critical catalyst for policy effectiveness, significantly influencing destination sustainability through an input-process-output-outcome-impact pathway. Empirical evidence from the case of Penglipuran Village, Bali, corroborates these results, demonstrating that indigenous institutional legitimacy enhances social responsiveness but remains vulnerable to overtourism-driven economic dependency. Notably, the study demonstrates that integrating SDGs into the policy evaluation cycle transforms assessments from mere administrative formalities into strategic instruments for long-term demand stability and ecosystem preservation. These findings position Sound Governance as a strategic intangible asset, offering theoretical contributions to development administration and practical guidance for policy-makers navigating the complexities of sustainable destination management in competitive global markets

This study aims to analyze the effect of labor proportion and industrial agglomeration externalities on the Gross Regional Domestic Product (GRDP) of the manufacturing sector in Indonesia. This research employs a quantitative approach using panel data covering 34 provinces over the period 2019–2023. The independent variables include labor proportion and industrial externalities represented by specialization index (MARshall–Arrow–Romer/MAR), competition (Porter), and diversity (Jacobs). The analysis method uses panel data regression with model selection through Chow, Hausman, and Lagrange Multiplier tests, where the Random Effect Model (REM) is selected as the best estimation model. The results show that labor proportion and MAR externalities have a positive and significant effect on manufacturing GRDP, highlighting the important role of labor and industrial specialization in driving regional output growth. In contrast, Porter and Jacobs externalities do not have a significant effect, indicating that industrial competition and diversity have not yet contributed substantially to manufacturing sector performance during the study period. Simultaneously, all independent variables significantly affect GRDP, although the model’s explanatory power remains relatively limited. These findings suggest that the growth of Indonesia’s manufacturing sector is more influenced by labor and industrial concentration rather than competition and diversification dynamics, and that other factors outside the model also play an important role in determining manufacturing sector performance.

The increasingly complex global energy problem drives the need for efficient, low-cost, and environmentally friendly energy storage systems. This study aims to analyze the power performance of two symmetric supercapacitor prototypes using Nitrogen-doped Graphene-Like Carbon (N-GLC) as the electrode material and 1 M  as the electrolyte, with different electrode substrates: aluminum and copper. Both prototypes were tested through charging and discharging processes using resistive loads of 470 ohms and 560 ohms for 5 minutes. The analyzed parameters include voltage, current, power, and output energy. The results show that the aluminum electrode achieved a higher maximum charging power of up to 18 mW; however, its energy discharge efficiency was very low at only 0.87%. In contrast, the copper electrode demonstrated a more balanced charging and discharging performance with an energy discharge efficiency of 19.4%. Analysis also indicates that the copper substrate maintains better voltage stability after 6 hours of storage compared to aluminum, which experienced significant degradation. Thus, the copper electrode is superior in maintaining the power and stability of a simple N-GLC-based symmetric supercapacitor system.

This research aims to design and develop a prototype wave power plant that utilizes the vertical motion of a buoy as a source of mechanical energy, which is then converted into electrical energy using a recoil starter mechanism. The system is designed to be installed at the stern of a prototype ship. The vertical movement of the buoy caused by ocean waves is transmitted to the recoil starter through a drive rope, producing a stable one-way rotational motion. This rotation is further transmitted to a gearbox to increase rotational speed before driving a DC generator. The electrical energy generated is stored in a 12 VDC battery, supported by a buck–booster converter to stabilize the output voltage. This study employs an experimental engineering approach to evaluate system performance based on empirical test data. The main components of the system include a buoy as a wave energy collector, a recoil starter as the initial rotating mechanism, a DC generator as the electrical energy producer, a buck–booster converter as a voltage regulator, a 12 VDC battery as an energy storage unit, and a monitoring system based on an ESP32 microcontroller integrated with a PZEM-017 sensor. Experimental results show that the recoil starter operates effectively in driving the generator under both no- load and buoy-loaded conditions. Increases in generator rotational speed are directly proportional to increases in output voltage and current. The PZEM-017 sensor demonstrates a high level of measurement accuracy, approaching 100% when compared with a multimeter. Overall, the proposed wave power generation system functions reliably and shows potential for further development as a small-scale alternative renewable energy source.

The increasing demand for electrical energy and the limited availability of fossil fuels have driven the development of renewable energy sources, including marine current energy, which remains underutilized in coastal and remote maritime regions. This study presents the design and realization of a small-scale marine current power generation prototype using a horizontal axis propeller turbine with a NACA S814 blade profile and analyzes the effect of turbine rotational speed on electrical power output. The system converts marine current kinetic energy into mechanical energy through turbine rotation and subsequently into DC electrical energy using a generator, which is stabilized by a Buck–Boost Converter and Maximum Power Point Tracking (MPPT) for charging a 12 VDC battery. Real-time monitoring of electrical and mechanical parameters is implemented using an Internet of Things (IoT)–based system comprising an ESP32 microcontroller, a PZEM-017 sensor, and an RPM sensor. Experimental results demonstrate a positive correlation between water flow rate, turbine rotational speed, and generator output voltage. The system begins operating at a minimum flow rate of 35.2 L/s at 56 RPM, producing 0.2 V, while optimal performance is achieved at 45.3 L/s and 516 RPM, generating up to 13.3 V. These results indicate that the proposed prototype is a viable alternative renewable energy source for marine applications.

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).

Gununganyar Reservoir in Tuban Regency is one of the reservoirs used as a source of livelihood for the local community. However, further development and utilization of Gununganyar Reservoir have yet to be undertaken. The development of a small-scale floating Photovoltaic Solar Power Plant (floating solar panels) at Gununganyar Reservoir, aimed at providing an alternative and renewable energy source for operating raw water pumps and for supporting the Gununganyar Nature Tourism (WAG) initiative, constitutes an innovative and strategic effort to enhance energy efficiency and environmental sustainability in rural areas. This study focuses on the design and performance assessment of a floating solar panel system constructed with processed bamboo as an alternative floating material replacing HDPE, while integrating local wisdom and environmental conservation principles to minimize the reservoir’s carbon footprint. The methodology employs a simple quantitative approach combined with a literature review of relevant studies. Based on the analysis, the design of this small-scale floating solar panel system utilizes a 170 Wp off-grid solar module mounted at a tilt angle of approximately 7,1°, capable of generating a peak power output exceeding 2,962 kWp and supported by a battery capacity of  328,33 Ah. The implementation of these floating solar panels is expected to serve as a model for reservoir development by promoting energy self-sufficiency, stimulating local economic growth, and contributing to the achievement of net zero emissions by 2060.

The lack of street lighting infrastructure on the connecting roads between hamlets in Tepansari Village hinders community mobility and increases security risks at night. This community service program aims to implement Solar Power Street Lighting (PJUTS) technology as a renewable energy solution while building infrastructure independence through community empowerment. The implementation method uses the Asset-Based Community Development (ABCD) approach which includes five stages: discovery, design, define, delivery, and destiny. The program involved a collaboration between 7 KPM students, 2 village officials, and 10 local residents. The results of the service show that two PJUTS units have been successfully installed at strategic points and are functioning optimally independently without the burden of village electricity costs. In addition to physical outputs, this activity succeeded in increasing the technical capacity of residents in preventive maintenance of solar panel and battery components through a learning-by-doing process. The immediate impact felt by the community is an increased sense of security and mobility comfort, which supports social-religious and economic activities at night. This program proves that the integration of appropriate technology and participatory empowerment is an effective strategy in realizing sustainable rural infrastructure independence in accordance with SDGs point 7 targets.

The increasing demand for electrical energy each year and the high dependence on fossil energy, which has negative environmental impacts, necessitate the development of alternative renewable energy sources. One potential source that can be utilized is mechanical energy from human activities through the application of piezoelectric technology in paving blocks. In addition, studies on the effect of piezoelectric circuit configurations, particularly comparisons between series and parallel circuits in generating electrical power, are still limited. This study employed an experimental method using a piezoelectric paving block prototype, with testing conducted under a static load of 60 kg. The measured parameters included output voltage and current, which were then used to calculate the generated power. The experimental results show that the parallel circuit configuration produced a higher average electrical power of 1.51 mW compared to the series circuit, which generated an average power of 1.37 mW. The increase in power in the parallel configuration was mainly influenced by the higher output current, while the difference in voltage was relatively insignificant. These findings contribute to determining a more optimal circuit configuration for the development of piezoelectric paving blocks as a renewable energy harvesting system based on mechanical pressure.

Motorcycles are one of the main modes of transportation widely used by the Indonesian people due to their practicality, efficiency, and ability to support daily mobility. However, many motorcycle users complain about the suboptimal engine power, especially when the vehicle is used on extreme terrains outside urban areas, such as uphill roads, rocky paths, or long distances. This situation has driven the development of various innovations in the automotive field to improve engine performance. One widely applied method is the oversize technique on the piston and piston block, which aims to increase the combustion chamber capacity, thereby maximizing the power output. This study aims to analyze the significant comparison of engine performance after the application of the oversize method on the KVY engine type, as well as to examine the factors influencing the optimization of engine performance based on the philosophy and needs of the vehicle owner. The testing method used a dynamometer to measure the increase in torque and engine power. The test results showed that the daily oversize application resulted in a torque increase of 1.19 Nm and a power increase of 0.85 Hp compared to the standard condition. Meanwhile, the oversize for competition needs showed more significant improvements, with a torque increase of 7.97 Nm and a power increase of 8.12 Hp. These findings demonstrate that the oversize method can significantly enhance engine performance according to its intended use.

The advancement of automotive technology has accelerated the adoption of renewable‑energy‑based electric vehicles, including the integration of solar panels on electric scooters. Indonesia’s tropical climate provides abundant solar energy potential; however, the limited surface area of scooters often restricts panel placement to the footrest section. This study aims to evaluate the impact of using a 10 mm clear acrylic cover on the performance of a 50 Wp monocrystalline solar panel in an electric scooter battery‑charging system. An experimental method was employed by comparing the panel’s performance under two conditions: without a cover and with the acrylic cover installed. Key parameters observed included voltage, current, and charging power, recorded using a data logger. Tests were conducted for 30 minutes under varying solar radiation intensities. The results indicate that the acrylic cover reduces the panel’s output power, from 55 W to 45 W at a solar radiation intensity of approximately 1100 W/m². These findings suggest that the use of an acrylic cover must be carefully considered to maintain optimal charging system performance.

The advancement of automotive technology has accelerated the adoption of renewable‑energy‑based electric vehicles, including the integration of solar panels on electric scooters. Indonesia’s tropical climate provides abundant solar energy potential; however, the limited surface area of scooters often restricts panel placement to the footrest section. This study aims to evaluate the impact of using a 10 mm clear acrylic cover on the performance of a 50 Wp monocrystalline solar panel in an electric scooter battery‑charging system. An experimental method was employed by comparing the panel’s performance under two conditions: without a cover and with the acrylic cover installed. Key parameters observed included voltage, current, and charging power, recorded using a data logger. Tests were conducted for 30 minutes under varying solar radiation intensities. The results indicate that the acrylic cover reduces the panel’s output power, from 55 W to 45 W at a solar radiation intensity of approximately 1100 W/m². These findings suggest that the use of an acrylic cover must be carefully considered to maintain optimal charging system performance.

Engine performance is a critical parameter in automotive engineering as it directly affects power output, torque characteristics, and overall vehicle efficiency. One of the components that significantly influences engine performance is the exhaust system, which regulates exhaust gas flow and back pressure. This study aims to experimentally analyze the effect of replacing a standard exhaust system with an aftermarket exhaust system on the performance of a 2NR-VE engine. The research employed an experimental method using a comparative design with two testing conditions: a factory-standard exhaust system and an aftermarket exhaust system. Engine performance testing was conducted using a dynamometer (dyno test) to measure horsepower and torque across various engine speed ranges (RPM). Each testing condition was performed repeatedly, and the resulting data were averaged to reduce measurement errors and minimize the influence of operational fluctuations. The experimental results indicate that the aftermarket exhaust system significantly improves engine performance. The maximum power increased from 82.5 HP to 91.6 HP, while the maximum torque rose from 131.2 Nm to 154.4 Nm. These improvements suggest that the aftermarket exhaust configuration effectively reduces exhaust back pressure and enhances exhaust gas flow efficiency. Therefore, replacing the exhaust system can be considered an effective approach to improving engine performance, provided that the modification is technically appropriate and complies with applicable emission and noise regulations.

This study aims to design and test a Dual Axis Solar Tracker to improve the energy absorption efficiency of solar panels on ships. The system is designed with a two-axis movement mechanism (horizontal and vertical) using a linear actuator motor controlled by Arduino Nano and ESP32. Testing was conducted on a 20 WP solar panel in Surabaya for 30 days, divided into three methods: 10 days using an LDR sensor, 10 days using an RTC, and 10 days in static conditions without a sensor. Voltage, current, and power data were measured every 30 minutes at 07.00–17.00 WIB. The test results show that the RTC method provides the highest and most stable output power, according to the sun's movement patterns in tropical areas, while the LDR method responds quickly to changes in light intensity but is less stable in changing weather. Static installation produces the lowest power. This system is able to maintain the panel orientation perpendicular to the sun's rays, thus increasing energy efficiency compared to static systems. These findings prove that dual-axis solar tracker technology, especially with an RTC sensor, is effective in dynamic maritime environments and can be a practical solution for optimizing renewable energy on ships. The most effective results using RTC sensors demonstrated the most stable and high power output, especially since the sun in tropical areas like Surabaya moves fairly consistently following a cyclical pattern. The success of this system not only increases the energy output of solar panels but also provides a practical solution for renewable energy applications in tropical climates.

The development of renewable energy, particularly Solar Power Plants (PV), requires a reliable, real-time, and easily accessible electrical energy monitoring system to ensure optimal system performance. This study aims to design and implement an Internet of Things (IoT)-based electrical energy monitoring system for PV using the NodeMCU ESP32 microcontroller, the PZEM-004T sensor for measuring electrical parameters, and the Node-RED platform as the data visualization interface. The developed system is designed to monitor voltage, current, power, energy, frequency, and power loss in real time, and then display the data in the form of numerical values, graphs, and indicators on a dashboard accessible through a local network. The research method includes hardware design, software development (sensor reading, data processing, and communication), integration with Node-RED, and system testing on a small-scale PV installation. The test results show that the system is capable of monitoring electrical parameters in a stable and responsive manner. Variations in sunlight intensity were found to affect the current and power produced by the solar panels, whereas the inverter output voltage tended to remain within normal operating ranges. The Node-RED dashboard display was considered informative and helpful for users in monitoring and analyzing PV performance. Based on these results, it can be concluded that the IoT-based electrical energy monitoring system designed in this study functions well and is feasible for application in residential or educational-scale PV installations. The system still has the potential for further development through cloud service integration, the addition of environmental sensors, and enhancements to data analysis features and user interface design.

The problems in rice fields are complex and varied, depending on geographic location, rice variety, and growing season. Pests often cause serious economic losses. The Solar Sonic Repeller is an innovative portable pest control device designed to address pest problems by utilizing renewable energy, specifically solar energy. This product aims to offer an environmentally friendly and efficient solution. It works by emitting ultrasonic sound waves with a frequency of 30,000–40,000 Hz. The device's advantages lie in its portability and energy independence, thanks to the use of a charging module powered by an integrated photovoltaic (PV) panel with automatic battery charging during the day. The first test measured the output frequency using an oscilloscope to verify that the oscillator circuit produced waves at the specified frequency. The second test measured the device's effectiveness by examining the pest response to the device at various distances. This test was effective within a maximum radius of approximately 14 m from the center point, covering a rice field area of ​​250 m2.

This study explores the influence of childhood memories, particularly the experience of "unresolved revenge" in the form of a failed tricycle ownership, on the process of creating works of art. This phenomenon is analyzed through the lens of psychoanalysis and consumerism criticism, where childhood fantasies transform into an obsession with collecting in adulthood, as an outlet for powerful passionate sensations. Qualitatively, works of art are positioned not only as manifestations of personal expression, but also as sustainable and critical practices. The articulation of art becomes a way to resolve consumerist trauma in a non-physical way, transforming the urge for unsustainable material accumulation (the infatuation of collecting) into artistic output that reflects and critiques the symbolic prestige value of commodities in the 1980s. This study concludes that personal memory-based art practices offer a sustainable framework for psychological recovery and social critique of the endless cycle of material desires.

Accurate wind turbine power curve modeling plays a crucial role in performance evaluation, energy yield estimation, and data-driven control strategies. However, actual power curves often exhibit non-linear behavior influenced by atmospheric variability, measurement noise, and SCADA anomalies, making conventional modeling approaches less effective. This study proposes an optimized logistic power curve model whose parameters are tuned using Particle Swarm Optimization (PSO) to improve predictive accuracy. The analysis uses the Wind Turbine SCADA Dataset from Kaggle, which undergoes extensive preprocessing including physical rule filtering, outlier detection with the Interquartile Range (IQR) method, anomaly removal, and smoothing of the power signal. A three-parameter logistic model is selected due to its ability to capture the typical S-shaped relationship between wind speed and power output. PSO is applied to identify optimal model parameters by minimizing the Mean Squared Error (MSE), utilizing 40 particles over 200 iterations. The optimized model achieves strong predictive performance with RMSE of 404.09, MAE of 179.96, and R² of 0.904 on the test set, indicating that more than 90% of the variability in actual power can be explained by wind speed. Residual analysis reveals heteroscedastic patterns and slight overestimation in mid-range wind speeds, yet overall model consistency remains high. Comparative evaluation against Linear Regression, Random Forest, and logistic modeling using curve_fit shows that the Logistic–PSO approach provides the most accurate and stable predictions. These findings demonstrate that combining logistic modeling with PSO offers an effective and robust method for data-driven wind turbine power curve optimization.