Bidang kajian dalam jurnal ini termasuk sub rumpun Ilmu Teknik Sipil dan Perencanaan Tata Ruang, Keteknikkan Industri, Teknik Elektrinika dan Komputer, Teknik Kebumian dan Perkapalan. Jurnal Riset Rumpun Ilmu Teknik diterbitkan 3 kali setahun : April, Agustus dan Desember. Print ISSN : 2829-0178, Online ISSN : 2829-016X Jurnal ini terakreditasi SINTA 5 (Surat Keputusan Direktur Jenderal Pendidikan Tinggi, Riset, dan Teknologi Nomor 10/C/C3/DT.05.00/2025 tanggal 21 Maret 2025 tentang Peringkat Akreditasi Jurnal Ilmiah Periode I Tahun 2025) dimulai dari Volume 1 Nomor 2 Tahun 2022 sampai Volume 6 Nomor 1 Tahun 2027.
Validitas Beton Mutu Tinggi Menggunakan Komparasi Campuran Bahan Feldspar terhadap Kuat Lentur
The development of science and technology generally brings positive impacts in terms of convenience in various human activities, but on the other hand, it also leads to negative consequences such as an increase in waste. One of the significant wastes produced from construction activities, including building and house construction, is feldspar, which typically comes from leftover ceramic materials. Feldspar is a type of waste that is difficult to decompose naturally and has no economic value, often accumulating and polluting the environment. Therefore, innovation is needed to utilize this waste to create value. This study aims to use feldspar powder as a replacement for fine aggregates in K-200 grade concrete mixtures. The research method involved mixing feldspar powder in specific proportions as a substitute for sand, followed by a series of tests, including compressive strength and flexural tests, to determine the feasibility and performance of the resulting concrete. The results indicate that the use of feldspar powder as a fine aggregate produces a concrete mixture with satisfactory mechanical characteristics, meeting the K-200 concrete standards. These findings not only provide an alternative environmentally friendly material but also offer a solution to reduce ceramic waste, contributing positively to sustainable construction.
Copyright (c) 2025 JURAL RISET RUMPUN ILMU TEKNIK https://creativecommons.org/licenses/by-sa/4.0
Perancangan Sequence Penambangan Bulan Januari dan Februari Tahun 2025 pada PT Putra Perkasa Abadi Site SKS
Mining sequence design is one of the important stages in open pit mining activities that aims to organize the excavation stages so that production activities run effectively, efficiently, and in accordance with the established targets. This research was conducted at PT Putra Perkasa Abadi Site SKS with the aim of designing a mining sequence in January and February 2025. The methods used include analysis of topographic data, geology, pit design, and monthly production targets. The data was processed using mining software to determine the excavation sequence based on elevation, overburden volume, and coal reserves. The design results show that the total planned overburden and coal volume is able to meet the company's production targets by considering slope stability and the efficiency of digging and loading equipment. In addition, the resulting sequence design also takes into account aspects of work safety and field operational conditions, such as mine road access and drainage systems. With a structured design, it is expected that mining activities during this period can run according to schedule, minimize operational obstacles, and support the achievement of production targets and cost efficiency at PT Putra Perkasa Abadi Site SKS.
Rancang Bangun Sistem Monitoring Pemanas Air dengan Media Pasir Silika dan Paraffin Wax Berbasis Internet of Things (IoT)
Energy efficiency in water heaters is a crucial factor in ship operational environments due to limited electricity resources that rely on generators. This study aims to design and build an IoT-based water heater monitoring system with an innovative heat storage medium in the form of a mixture of silica sand and paraffin wax to improve thermal efficiency. Although previous studies have developed temperature monitoring and control systems in IoT-based water heaters, this study specifically fills this gap by analyzing the performance of adding silica sand to overcome the low thermal conductivity of paraffin wax. Using the Research and Development (R&D) method, this system was built with an ESP32 microcontroller as the control center, a DS18B20 temperature sensor for accurate measurements, and the Blynk and Google Sheets platforms for real-time monitoring and data recording. Performance testing was conducted by comparing the water heating rate between pure paraffin wax media and the mixed media. The results showed that the monitoring system functioned reliably, and the main finding proved that the addition of silica sand to paraffin wax significantly increased heating efficiency. This was clearly seen from the reduction in time required to raise the water temperature to 40°C, from 2.5 hours to only 1 hour in the second heating cycle. The results of this study indicate that the integration of silica sand and paraffin wax media with IoT technology can increase the efficiency of water heaters and provide an innovative solution for energy-efficient and environmentally friendly temperature control.
Copyright (c) 2025 JURNAL RISET RUMPUN ILMU TEKNIK https://creativecommons.org/licenses/by-sa/4.0
Analisis Keselamatan dan Kesehatan Kerja (K3) pada Proyek Otomatisasi Mesin Vacum Pan di Pabrik Gula
This research analyzes the implementation of Occupational Safety and Health (K3/OSH) in the automation project of the Vacuum Pan machine at a sugar factory in Indonesia. The Vacuum Pan machine automation project poses high potential hazards due to its involvement with electrical systems, high-pressure pipes, and the installation of electrical and automatic control systems. The research methods used were daily direct observation in the field and interviews with the factory's safety (EHS) personnel, project workers, and interns for one month, from July 7 to August 8, 2025. The results show that K3 planning, such as the availability of HIRADC documents, SOPs, Safety Plans, and K3 facilities (APAR, evacuation routes, safety signs), has been well-implemented and adheres to applicable standards. K3 supervision activities include Safety Inspection (routine twice a week), Safety Patrol (daily and spontaneous), and Safety Talk or Toolbox Meeting (routine every Wednesday). However, the aspect requiring improvement is worker discipline, particularly in the use of Personal Protective Equipment (PPE) and adherence to Standard Operating Procedures (SOPs), which were recorded at compliance frequencies of 65% and 60%, respectively. Workers' response to hazardous situations was also found to be less responsive (50%). In conclusion, while K3 planning and facilities are adequate, the overall K3 implementation needs to be optimized through increased supervision and the establishment of a disciplined culture regarding PPE and SOPs.
Peningkatan Akurasi Perhitungan IEEE C37.114 Double Ended Dengan Metode Selective Mode
Rapid and precise handling in determining fault locations is essential to accelerate post-fault recovery and minimize economic losses caused by power outages. Several methods employed to identify fault locations include Single Ended and Double Ended analysis. This paper discusses the Selective Mode Double Ended Fault Locator Method, an enhancement of the IEEE C37.114 Double Ended method. This approach involves selecting maximum fault data values for Near Side (NS) and Far Side (FS) calculations, taking into account the differential or angle difference of the sequence between the two sides. The Double Ended calculation results from the total sample values are used to determine the mode, which serves as the final output of this Fault Locator method. This method is designed to identify faults and their locations with high accuracy and speed. Based on the research findings, the Selective Mode Double Ended (SMDE) method provides more accurate fault locator analysis compared to the Single Ended and Double Ended methods. The accuracy achieved with the Single Ended method is 90.9%, with the Double Ended method reaching 94.9%, and with the Selective Mode Double Ended (SMDE) method achieving 99.9%.
Studi Karakteristik Mekanik Komposit Kayu Randu Bermatrik Asam Sitrat
This paper was made to explain the results of research on how to obtain the most appropriate citric acid adhesive composition in the manufacture of randu wood fiber composites in order to obtain a strong and suitable composite material. The research was carried out by experimental methods in the laboratory through a series of mechanical tests, namely the bending strength test and the screw grip strength test. The sample specimen is 5 cm × 20 cm × 1 cm for flexural strength testing and 5 cm × 10 cm × 1 cm for screw grip strength test. Composite specimens were made with variations in the composition of citric acid adhesives of 2.5%, 5%, 7.5%, 10%, 12.5%, 15%, 17.5%, and 20% by weight of randu wood. The results showed that the composite of randu wood particles with a citric acid matrix had optimal strength at a certain ratio, which was 7.5%. At the same ratio, the test results of the screw grip strength test also provide the highest value. These findings confirm that the exact composition of the adhesive has a significant impact on the final performance of the resulting composite.
Analisis Efektivitas Integrasi Feeder pada Sistem Bus Rapid Transit (BRT) Kota Medan Berbasis Analisis Spasial
This study aims to analyze the effectiveness of the integration of the Bus Rapid Transit (BRT) system with feeder transportation in improving the connectivity and accessibility of public transportation in Medan City. The research methods used include field surveys, interviews, and spatial analysis based on Geographic Information Systems (GIS) to map the transportation network and assess the scope of services. The analysis was carried out by comparing the existing conditions of the BRT (Corridors 2 and 3) and the results of the simulation after the integration of five feeder routes (A2, A3, A6, A7, and A8). The results show that the integration of feeder routes is able to increase service coverage from 57.84 km² to 128.84 km² (an increase of 122.8%), as well as expand the served area from 23 to 44 zones, with an increase in service ratio from 26% to 57%. In addition, the average distance to the bus stop decreased from 1.2 km to 0.6 km, and the route overlap was reduced by 40%. Spatially, areas with high accessibility (<500 m from bus stops) have increased significantly in city centers such as Merdeka Square and Petisah Market. This study concludes that the integration of BRT and feeder is an effective strategy to realize a sustainable, efficient, and inclusive transportation system in the city of Medan. The implementation of a rotating operating system is also recommended to optimize the fleet without the need for the addition of new vehicles.
Review : Klasifikasi dan Sifat Mekanis Tanah Asli di Pulau Bintan sebagai Subgrade Perkerasan Jalan
Bintan Island has abundant bauxite soil resources; however, its utilization as road construction material remains limited. The scarcity of high-quality granular material in the region necessitates the use of available local resources, particularly for pavement subgrade layers. This article aims to analyze the classification and mechanical properties of native soils in Bintan Island through a systematic literature review. The reviewed literature includes laboratory test results of bauxite soil. The findings indicate that bauxite soil exhibits low plasticity, relatively high CBR values (±35%), and is classified as CL (USCS) and A-2-4 (AASHTO). These results suggest that bauxite soil is suitable for subgrade applications, although require stabilization with binding agents. The implication of this review highlights that the utilization of local materials could support sustainable infrastructure development in island regions by reducing dependency on imported materials.
Analisis kapasitas Daya Tampung Settling Pond di Pit Alfa Utara di PT. Hamparan Mulya
PT. Hamparan Mulya operates in the coal mining industry and applies an open-pit extraction system. In this mining method, managing surface water particularly rainwater is essential to ensure smooth operations. An effective drainage system is required to prevent runoff water from contaminating nearby rivers, lakes, and surrounding ecosystems. One practical approach used in mining operations is the construction of settling ponds, which function as treatment units for water collected in the sump before it is released into natural waterways. This study aims to identify the appropriate storage capacity for the settling pond and sump by analyzing rainfall data using the Log Pearson Type III method. The analysis produced a design rainfall value of 507.16 mm/day and a rainfall intensity of 56.94 mm/hour. With a catchment area of 14 km², the resulting runoff discharge reaches 30,782.16 m³/hour. Based on these parameters, the settling pond must be engineered to accommodate a total discharge of 30,782.16 m³/hour.
Perancangan Dimensi Sump di PT. Satria Alam Manunggal Site Telen Orbit Prima Desa Buhut Kecamatan Kapuas Tengah Kabupaten Kapuas Kalimantan Tengah
This study aims to evaluate the actual sump capacity in accommodating mine water discharge, design a sump that fits field conditions, and determine the optimal pump capacity and system at PT Satria Alam Manunggal, Telen Orbit Prima Site. The research methods include field data collection (sump condition, water discharge, and pump capacity) and supporting data (rainfall, geological maps, and pump specifications). The design rainfall was calculated using the Gumbel method with a five-year return period, while water discharge was estimated from runoff, rainfall, and groundwater inflow. The results indicate that the existing sump, with a capacity of 508 m³, is insufficient to accommodate an inflow of 1.210 m³/s. Therefore, two new sumps were designed: the West Sump with a capacity of 38,400 m³ and the East Sump with 78,281 m³. Each sump employs a DnD 150-4H pump with a discharge rate of 480 m³/hour. The West Sump pump can drain water within approximately three days, while the East Sump requires about seven days. The trapezoidal sump design was chosen for its efficiency, structural stability, and effectiveness in sediment (TSS) deposition control, maintaining levels within safe limits. In conclusion, the design of the West and East sumps is considered optimal in accommodating mine water discharge and improving the overall effectiveness of the mine drainage system.
Antisipasi Penanganan Masalah pada Praktek Keinsinyuran untuk Pekerjaan Penanganan Longsoran dengan Menggunakan Bore Pile
In engineering practice, various methods have been implemented to stabilize landslide-prone slopes, one of which is the use of bore piles. Bore piles are structures that hold back soil and make slopes more stable by reinforcing the ground inside them. However, the application of bore piles in landslide mitigation presents its own challenges, making it essential to identify and anticipate potential issues that may arise in field engineering practice. Bore piles are installed vertically, either parallel or staggered, at specific spacing and are often combined with capping beams and struts to resist soil movement and provide lateral restraint. This method is commonly applied to high-risk slopes or critical infrastructures such as roads, bridges, and buildings. Anticipation strategies in engineering practice consist of three stages: planning, implementation, and long-term maintenance, with this study focusing specifically on anticipation strategies during the implementation stage. Although bore piles serve as an effective solution to reduce landslide risk, their success depends heavily on proper planning, construction execution, and maintenance. Issues such as soil conditions, construction quality, and external factors must be addressed through a comprehensive engineering approach.
Pengaruh Sistem Pencahayaan Berbasis Smart terhadap Penghematan Energi
The increasing demand for electrical energy, particularly in offices and commercial buildings, has made energy efficiency a critical aspect of sustainable development. Among various building components, lighting systems are recognized as one of the major consumers of energy. This study investigates the potential for energy savings through the adoption of a smart lighting system incorporating IoT-based sensors, motion detectors, and dimming controls. Employing a quantitative descriptive approach, the research was conducted at the workspace of Indie Light, comparing energy consumption before and after the implementation of the system. Data were collected using direct observation, light and power meters, and real-time monitoring devices to ensure accurate measurement. The results demonstrate that smart lighting systems can substantially reduce energy use without compromising lighting quality or comfort. By integrating intelligent sensors and adaptive control algorithms, the system not only optimizes energy efficiency but also aligns with national policies on energy conservation, supporting broader environmental sustainability efforts. These findings suggest that smart lighting solutions can play a significant role in promoting energy-efficient practices in commercial spaces while contributing to sustainable development goals.
Perancangan Resort dengan Pendekatan Arsitektur Berkelanjutan di Kabupaten Serdang Bedagai
The principle of sustainability is the main foundation in the development of a coastal resort in Mangrove Beach, Serdang Bedagai, which has high tourism potential but lacks environmentally friendly facilities. This study uses a sustainable architectural design method based on Biophilic design, which emphasizes human connection with nature through adaptive design and harmony with the environment. The implementation of this concept is realized through the use of locally sourced low- carbon materials, cross-ventilation, and natural lighting for energy efficiency, integration of vegetation as both aesthetic and ecological elements, environmentally friendly rainwater and waste management, and site planning that respects the coastal ecosystem. The design outcome is a resort with an organic form inspired by shells and ocean waves, creating an architectural identity that harmonizes with the area's character, providing a comfortable tourist experience for visitors, and contributing to local economic growth and environmental conservation, thereby serving as a concrete example of sustainable coastal tourism development in North Sumatra.
Analisis Kinerja Trafo Distribusi pada ULP Medan Kota dan Penanggulangannya dengan Sisip Trafo
Distribution transformers play a critical role in delivering electrical energy from medium-voltage networks to low-voltage consumers. At ULP Medan Kota, several distribution transformers have been operating with loads exceeding 80% of their nominal capacity, posing risks of overloading, efficiency reduction, and equipment failure. This study aims to analyze the performance of distribution transformers based on actual load data and evaluate mitigation strategies through the implementation of additional parallel transformers (trafo sisip). The methodology includes data collection, load and current calculation, and simulation of load distribution after transformer insertion. The results show that the installation of trafo sisip reduces the load on the main transformer by approximately 50% and significantly lowers the current to safer levels. Moreover, placing the trafo sisip at an optimal position minimizes voltage drop to as low as 0.0745 Volts. Therefore, the addition of trafo sisip is proven to enhance the reliability, efficiency, and operational life of the power distribution system at ULP Medan Kota.
Analisa Usaha Ternak Domba dengan Pola Pemeliharaan Intensif dan Semi Intensif di Desa Suka Raya Kecamatan Pancur Batu
This study aims to analyze the profitability and feasibility of sheep farming using intensive and semi-intensive rearing sistems in Suka Raya Village, Pancur Batu Sub-district. The research employed a survey method with purposive sampling, involving 16 farmers (8 intensive and 8 semi-intensive), each rearing more than 15 sheep and operating for at least 3 years. Data were collected through questionnaire interviews and field observations, then analyzed descriptively to calculate production costs, revenue, income, R/C ratio, and Break Even Point (BEP). Results showed that the average total production cost for the intensive sistem was Rp 52,429,313, higher than the semi-intensive sistem at Rp 39,664,375. The average revenue for the intensive sistem was Rp 69,150,000, while the semi-intensive sistem was Rp 63,712,500. The average income for intensive farmers was Rp 16,720,688, compared to Rp 24,048,125 for semi-intensive farmers. The average R/C ratio for the intensive sistem was 1 (near break-even), while the semi-intensive sistem was 2 (more efficient and profitable). BEP analysis indicated higher sales for the intensive sistem (Rp 844,022/sheep/period) compared to the semi-intensive sistem (Rp 691,052/sheep/period), with a larger production BEP for the intensive sistem (44 sheep) than the semi-intensive sistem (33 sheep). The semi-intensive sistem is recommended for farmers with limited capital and small to medium-scale operations due to lower costs and higher profit margins, while the intensive sistem is more suitable for large-scale operations with adequate capital, feed management, and health care.
Analisis Manajemen Penimbunan Batubara pada Area Stockpile di PT. Barito Bangun Nusantara
PT. Barito Bangun Nusantara is a company engaged in coal exploration and production activities, where the production is temporarily stored in a stockpile area before being processed or distributed. Stockpile management requires attention to several important factors, such as area design and stockpiling methods, so that storage runs effectively and does not cause a decrease in coal quality. This study was conducted on old and new stockpiles with the aim of analyzing the actual stockpiling conditions and providing technical recommendations regarding the ideal stockpile capacity and configuration. The research methods included field observation, primary and secondary data collection, and descriptive quantitative analysis. The results showed that both stockpiles experienced inefficiencies due to excess capacity. The actual tonnage reached 49,191.98 tons, exceeding the planned capacity of 35,000 tons, with a stockpile height reaching 9 m. This condition caused long stacking times and the FIFO system did not operate optimally. The study recommended an ideal stockpile capacity of 30,740.61 tons, with a maximum height of 8 m. The recommended angle of repose for the old stockpile is 30°, with a capacity of 11,542.19 tons, while for the new stockpile, it's 34°, with a capacity of 19,198.42 tons. This arrangement is expected to allow for a smoother unloading process and a more ideal stockpile.
Sistem Keamanan Sepeda Motor menggunakan Modul GPS Neo-7M, Selenoid Key Berbasis ESP8266
Motorcycle theft remains a widespread issue that demands improved security solutions supported by modern technology.This research discusses the development and implementation of a motorcycle security system design using an ESP8266 microcontroller integrated incorporating the GPS Neo-7M positioning module, SW-420 vibration detection sensor, and an electronically controlled solenoid lock. The implemented mechanism is monitored and controlled via the Telegram application, allowing the owner to receive real-time updates about the motorcycle’s status through a Telegram Bot. The development process involves hardware integration, ESP8266 programming, and functional testing. The SW-420 sensor detects vibrations as indicators of possible theft, triggering a buzzer alarm and sending instant notifications through Telegram. The GPS Neo-7M module provides location data in real time, automatically or upon user request, through a Google Maps link. Users can also lock or unlock the motorcycle remotely by sending the lock or /unlock commands via Telegram. Test results show that the system responds to vibrations in less than one second, delivers Telegram notifications within 3–5 seconds, and determines location with an accuracy of 3–10 meters. Overall, the proposed system offers an effective, practical, and low-cost solution to enhance motorcycle security.
Analisis Kesesuaian Realisasi di Lapangan terhadap Rencana Penambangan Bulan Maret 2025 di Pit P3BK4 PT Tama Raya provinsi Kalimantan timur
This study was conducted to evaluate the level of conformity between actual mining activities in March 2025 and the monthly sequence design plan at PT Tama Raya's P3000BK14 pit. The evaluation focused on geometric deviations, volume achievement, and changes in field conditions that influenced these discrepancies. The data used included the sequence design, actual topography from the TLS (Low-Scale Land Survey), and weekly production realizations. The results showed significant discrepancies between the planned and actual operations in weeks 2 and 4, primarily in the form of overcuts, undercuts, non-designed contour changes, thinning of the coal seam, and hydrological obstacles such as ponding and unstable drainage. The R2 sequence redesign in week 4 proved to improve the overburden excavation flow but did not fully restore coal access due to persistent geological and water conditions. These findings emphasize the need for more rapid topographic updates, more intensive water handling, and interdepartmental coordination to ensure better synchronization of plans and operations.
Rancang Bangun Simulator Modul Kendali untuk Motor Operasi Katub Sebagai Media Pembelajaran Bagi Para Teknisi Baru di PLTU Nagan Raya
The Motor Operated Valve (MOV) is a critical component in fluid control systems at Steam Power Plants (PLTU). Training new technicians is often hindered by limited access to actual equipment and operational safety risks. This research aims to design and develop an Arduino-based MOV control module simulator capable of simulating basic functions such as open, close, stop, and limit switch responses. The method used is Research and Development (R&D) with an experimental approach. The simulator was tested using a DC motor as the simulated valve actuator, equipped with push buttons, relays, limit switches, and indicator lamps for visual feedback. The test results showed that the simulator successfully represented control functions with 100% accuracy in limit switch responses and consistent operation. User evaluations involving ten new technicians indicated an 85% satisfaction rate in terms of ease of understanding and operational safety. This simulator has proven to be an effective, interactive, and safe learning medium for new technicians at PLTU Nagan Raya.
Sistem Absensi Siswa di SMK Negeri 1 Indralaya Utara Menggunakan Fingerprint dan Rekam Kamera yang Terintegrasi Telegram Berbasis Arduino
The distinctive markings on the fingers are known as biometrics. The fingerprint attendance method uses biometrics. Without developing a usable fingerprint tool, research on fingerprint attendance is restricted to processing attendance data. As a result, an Arduino-based fingerprint approach was used to construct an attendance tool. The education sector is where SMK Negeri 1 Indralaya Utara. The school's student attendance system is still operated manually. In this study, the system uses fingerprints and camera recording to track students' locations. Using an Arduino Mega as a microcontroller, this tool will display student attendance information on an LCD, save it on an SD card module, and send the ESP32CAM-generated photographs over Telegram. The literature review is the first step in the research process, followed by hardware and software design. Following completion, the tool is put through testing to evaluate its functionality. Each of the ten participants scanned their thumb and index finger. The thumb and index finger have an average of five tests, with a 0.28% mistake rate, depending on the number of trials. Each component's error percentage is less than 1% while still falling within the 5% tolerance limit. The image test results indicate two conditions: 20 cm and greater. The ESP32CAM will activate when we take a picture at a distance of 20 cm.
Analisis Perencanaan Mutasi Trafo pada Gardu CMY dengan Metode Least Square untuk Keandalan Sistem Distribusi di PT PLN (Persero) ULP Labuan
Distribution transformers play a crucial role in delivering electrical energy from the distribution system to consumers to ensure power quality and supply continuity. However, in practice, overload conditions often occur due to increasing demand and load growth that exceed the transformer’s rated capacity. This situation can lead to reduced efficiency, increased power losses, and accelerated equipment aging. This study aims to analyze the performance of the CMY distribution transformer at PT PLN (Persero) ULP Labuan, which operates beyond its nominal capacity, and to propose an alternative solution through transformer mutation, namely the replacement of the existing unit with a transformer of more appropriate capacity based on load analysis results. The Least Square Method is employed to predict future load growth and determine the projected time when the transformer will again experience overload after the mutation. The results indicate that the existing 100 kVA transformer is overloaded and should be replaced with a 160 kVA unit. After the mutation, the loading percentage decreases significantly, the transformer’s lifespan is extended, and the reliability of the distribution system improves. Furthermore, the Least Square prediction suggests that the new transformer may experience overload again in future years if no further planning is carried out. Therefore, transformer mutation can be considered an effective and medium-term solution to enhance and maintain the reliability of the electrical distribution system within the operational area of PT PLN (Persero) ULP Labuan.
Industri Bioplastik Starch-Cellulose Blend Tandan Kosong Kelapa Sawit dalam Pemenuhan Sustainable Development Goals
Indonesia is the world’s second largest contributor of plastic waste entering the oceans, where it degrades into microplastics smaller than 1 micron. The use of bioplastics is therefore essential to mitigate environmental pollution. One promising alternative is starch–cellulose blend bioplastic derived from empty fruit bunches (EFB) of oil palm. Indonesia produces about 56.35 million tons of EFB annually, containing approximately 40% cellulose, which makes it a potential raw material for bioplastic production, although commercialization has not yet been realized. Environmentally, converting EFB into bioplastics within the palm oil value chain represents a sustainable waste recycling strategy that transforms solid residues into higher-value products. In this design, soda cooking technology is employed to extract cellulose from EFB, utilizing about 16% of waste from a crude palm oil (CPO) mill with a capacity of 30 tons of fresh fruit bunches (FFB) per hour. The starch–cellulose blend bioplastic pellets are formulated using gelatinized cassava starch as the polymer matrix, glycerol as a plasticizer, polyvinyl alcohol (PVA) as a stabilizer, and cellulose as a filler. The designed production capacity of the EFB-based starch–cellulose bioplastic plant is 16,500 tons per year. This bioplastic industry is expected to contribute positively to achieving eight Sustainable Development Goals (SDGs), including Goals 1, 8, 9, 12, 13, 14, 15, and 17, thereby supporting Indonesia’s commitment to sustainable industrial development and a cleaner environment.
Karakteristik Komuter dan Moda Suroboyo Bus Electric Rute Purabaya-ITS di Surabaya
Urban mobility in Surabaya faces serious challenges due to the high ownership of private vehicles and the low use of public transportation. The Surabaya City Government launched Suroboyo Bus Electric in November 2024 as a sustainable transportation innovation on the Purabaya–ITS route. This study aims to analyze commuter preferences for the Suroboyo Bus Electric mode over private vehicles, by emphasizing functional factors (cost, travel time, comfort) and symbolic factors (status, identity, modern image). The research method used a quantitative descriptive approach with 400 respondents, primary data was obtained through questionnaires, while secondary data came from government documents and literature. The analysis was carried out through descriptive statistics, chi-square tests, and logistic regression. The results showed that the majority of respondents chose Suroboyo Bus Electric as the main mode (62%), with the dominance of young, middle-income users, and mostly women. Most of the respondents have one unit of private vehicle, but still use electric buses as a mode of complementing mobility. Travel destinations are dominated by social, economic, and educational activities, with an average travel time of 16–30 minutes. In terms of cost, more than half of the respondents spent Rp 5,000-Rp 10,000 per trip, indicating the affordability of fares. Symbolic factors also play an important role, where Suroboyo Bus Electric is perceived as a modern, clean, and sustainable city identity.
Penerapan BIM dalam Perhitungan Volume Pekerjaan dan Biaya Konstruksi Menggunakan Software Autodesk Revit pada Proyek Gedung Pengadilan Agama Sungai Raya
The calculation of work volume and construction costs is a fundamental aspect of project management, as errors in the estimation process can directly affect the preparation of the project budget. Many projects still use conventional methods for estimation, which are based on 2D working drawings with the assistance of Microsoft Excel, as seen in the Sungai Raya Religious Court Building project. This method is considered prone to calculation errors and less efficient due to the considerable amount of time required. With the advancement of technology, Building Information Modeling (BIM) has emerged, enabling automatic and integrated calculation of work volumes and construction costs through a three-dimensional digital model. This study aims to examine the implementation of BIM in the Sungai Raya Religious Court Building project and to compare the results of work volume and construction cost calculations between the BIM method using Autodesk Revit and the conventional method based on the project’s Bill of Quantity (BoQ). The research method was conducted by modeling the structural elements of the building, including pile caps, tie beams, columns, beams, floor slabs, and reinforcements. The results of work volume and construction cost calculations obtained from Autodesk Revit were then compared with the project’s BoQ as the conventional method. Based on the analysis, an average difference of 6.3% in work volume and 5.6% in construction cost was found, with the Autodesk Revit calculations showing slightly lower values compared to the project’s BoQ.
Pelaksanaan Show Case Meeting (SCM) pada Proyek Preservasi Jalan Girian – Kema – Rumbia – Buyat 2024
Road preservation is a type of maintenance that keeps roads in satisfactory working order by using preventive, corrective, rehabilitation, and reconstruction methods. This approach makes sure that the road stays usable for the entire time it is planned to be used. In practice, preservation projects often run into delays that can lead to important contract conditions. To avoid this, there needs to be a structured way to evaluate things through a Show Case Meeting (SCM). This study looks at how SCM was used in the 2024 Girian–Kema–Rumbia–Buyat Road Preservation Project to find out what caused the delays and how well the agreed-upon fixes worked. The method included looking at physical progress, differences between planned and actual performance, and how well the contractor did during SCM Stages I and II. The results indicate that the contractor failed to provide enough workers and move the right equipment, which led to the critical contract condition. SCM Stage I did not meet the required test-case target, but SCM Stage II did, showing that the contractor was able to meet the required performance targets and finish the work on time. These results show that SCM is an important way to control contracts and fix problems, which helps construction projects get done on time and well.
Transformasi Pemasaran Tradisional Ke Digital Marketing
The transformation of marketing strategies from conventional methods to digital marketing has become an important factor in the development of the beauty industry, especially for Make Up Artists (MUAs) in Bandung. This study aims to analyze the impact of digital marketing through social media on increasing customer interest and the number of MUA service users, with a case study of Iwan Haadi, a professional MUA in Bandung who is active on Instagram (@iwanhaadimakeup) and TikTok (@iwanhaadi). This research employs a descriptive qualitative method with a case study approach, using interviews, observations of social media activities, and documentation of digital promotional content. The results show that before implementing digital marketing, MUAs generally relied on conventional promotions such as word of mouth and collaborations with wedding organizers. However, technological developments have encouraged many MUAs to shift to social media to expand their promotional reach. Based on observations of Iwan Haadi and 20 other MUAs in Bandung, around 85% have utilized social media particularly Instagram and TikTok to showcase their portfolios and client testimonials. The implementation of digital marketing strategies has proven to increase brand awareness and the number of customers by up to 65% over the past two years. In conclusion, digital marketing has a significant influence on increasing customers and competitiveness among MUAs in Bandung. Consistent and creative use of social media is the key to attracting customer interest and strengthening a professional image in the modern beauty industry.
Analisis Risiko dengan Pendekatan Semi-Kuantitatif untuk Stabilitas Lereng Highwall pada PIT B1 PT. Pancaran Surya Abadi Kabupaten Kutai Kartenegara
Guaranteeing the geotechnical stability of slopes is an absolute prerequisite for the sustainability of open pit mining operations, considering the potential for multidimensional losses due to slope failure. The specific geological conditions at PIT B1 PT. Pancaran Surya Abadi, which is composed of sedimentary rocks (coal, sandstone, and claystone), are susceptible to degradation and softening, especially due to high rainfall that causes an increase in pore water pressure and a decrease in rock shear strength. This study aims to analyze the stability of highwall slopes using the Morgenstern-Price Method to determine the Safety Factor (SFF) value according to Ministerial Decree number 1827 K/30/MEM/2018, and continued with a semi-quantitative risk analysis. The analysis results show that the initial slope has a static SFF of 0.77 (Not Safe). After redesign, the recommended optimal single slope geometry is: sandstone (Height 5 m, Angle 20°, Berm 5 m) and claystone (Height 10 m, Angle 60°, Berm 5 m). This redesign resulted in a FK of 1.34 (Safe). Sensitivity analysis to groundwater level rise (GTL) showed that the GTL value remained safe (GTL ≥1.30) up to a 30% increase in GTL. However, a 40% to 80% increase in GTL caused the GTL to decrease (1.28–1.21), classified as Medium Risk. A 100% increase in GTL drastically reduced the GTL to 1.05, classified as High Risk. This study emphasizes the need for close monitoring and additional drainage to maintain the long-term stability of slopes under the influence of rainfall.
Penataan Sarana Prasarana Pasar di Kawasan Perumahan Vila Mutiara Cikarang Tata Kota dan Daerah
A market is a place where buying and selling transactions take place between sellers and buyers at a specific time and place. This definition encompasses several key elements: the presence of sellers, buyers, a specific place and time, and a transaction agreement. Such markets are also known as traditional markets. "Surprise" or "overflow" markets are markets that open suddenly and briefly. "Surprise" or "overflow" markets are increasingly common in various locations. There are many reasons why people enjoy shopping at these markets. One example is the very low prices, especially compared to shopping at supermarkets or malls. Over time, with the increasing demand for basic necessities, the "surprise" market, located along the road in the Vila Mutiara Cikarang housing complex, has also experienced gradual development. The number of traders and buyers has increased, the trading space has expanded, and transaction times have decreased. This "surprise" market is located along the road in the Vila Mutiara Cikarang housing complex, starting from the second block to the end of the road exiting the housing complex. The "surprise" market operates during peak hours, especially in the morning, when this time is not only for market activities but also for many activities such as going to work, school, and other activities.
Perancangan Dual Axis Solar Tracker Guna Efesiensi Panel Surya di Atas Kapal
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.
Desain dan Analisa Pengaruh Jumlah Mata Pisau Serta Ukuran Mesh terhadap Kapasitas Bubuk Cabai yang dihasilkan pada Mesin Penepung Cabai Tipe Disk Mill Ffc 15
Post-harvest handling of chili in Indonesia is still largely done manually, requiring a relatively long processing time and producing products with a non-uniform level of fineness. This condition impacts low production efficiency and the quality of processed chili. Therefore, the application of appropriate technology in the form of a chili flour machine is needed to increase production capacity and consistency. This study aims to analyze the effect of the number of blades and mesh size on the production capacity of a disk mill type FFC 15 chili flour machine. The research method used was an experiment with a factorial design, involving two variations in the number of blades, namely three and four blades, and three variations in mesh size, namely 0.5 mm, 1 mm, and 3 mm. Each treatment combination was carried out three times. The results showed that the number of blades and mesh size had a significant effect on the machine's production capacity. The best treatment combination was obtained by using four blades with a mesh size of 3 mm, which resulted in a production capacity of 6.84 kg/hour and a Composite Desirability value of 0.983. These results indicate that proper arrangement of machine components can increase the efficiency of post-harvest chili processing.
Analisis Komparatif Keamanan dan Kinerja Protokol Komunikasi pada Web of Things: Tinjauan Sistematis terhadap HTTP, CoAP, dan MQTT
The integration of the Internet of Things (IoT) into the Web of Things (WoT) offers cross-platform interoperability but presents significant security challenges for constrained devices. This study aims to evaluate the effectiveness and efficiency of security mechanisms in three major WoT protocols: HTTP, CoAP, and MQTT. The research methodology employs a Systematic Literature Review (SLR) following PRISMA guidelines, reviewing 22 selected articles published between 2020 and 2025. The analysis utilizes PICOC criteria to compare communication overhead, computational consumption, and security mechanisms such as DTLS, OSCORE, and TLS integration. The results indicate that CoAP, combined with OSCORE and EDHOC mechanisms, provides the optimal balance between energy efficiency and end-to-end security for resource-constrained devices. MQTT demonstrates superiority in throughput and data transmission speed but requires additional security layers to ensure data confidentiality. Meanwhile, HTTP dominates in terms of Web service integration and access control, despite having the highest overhead burden. In conclusion, no single protocol is superior for all scenarios; the choice of protocol in WoT architecture must be based on the trade-offs between latency, resource efficiency, and system security requirements
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Analisis Perbandingan Kinerja Struktur Gedung Akibat Penurunan Mutu Beton pada Proyek di Wilayah Lombok
This study analyzes a 10-floor multi-story lecture building in Lombok, focusing on the impact of concrete quality degradation on the building's performance. Due to limited material access, the actual on-site concrete quality changed from the design quality of fc 30 MPa to fc 24.9 MPa. The building structure was modeled in 3D using ETABS v22 software, and two structural models were compared: one with the design concrete quality (fc' 30 MPa) and one with the actual quality (fc' 24.9 MPa). The analysis evaluated dynamic performance, inelastic displacements, P-Delta effects, and reinforcement requirements. The comparison aimed to assess the impact of concrete degradation on structural stiffness, inter-story displacements, and reinforcement needs. The results show that concrete quality deterioration increases the structure's vibration period, inelastic displacement, and lateral forces due to P-Delta effects. While beam reinforcement requirements remain mostly unchanged, column reinforcement significantly increases, especially in columns with large axial forces. This study provides valuable insights into the technical consequences of concrete quality degradation and serves as a reference for evaluating structural redesigns in projects facing material limitations.
Analisis Perbandingan Daya Tahan Komposit Serat Alam dan Serat Sintetis pada Lingkungan Produksi Bersuhu Tinggi
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.
Penerapan Konsep STP dalam Manajemen Pemasaran Modern Studi Kasus Apple Inc.
This study aims to describe the implementation of the Segmenting, Targeting, and Positioning (STP) concept in Apple Inc.’s marketing strategy and to assess students’ perceptions as young consumers of Apple products. A descriptive qualitative approach was applied through a literature review supported by an online survey involving 30 students who use Apple products. Data were analyzed descriptively to relate Apple’s STP strategy to respondent preferences and satisfaction levels. The results indicate that Apple applies multidimensional market segmentation encompassing demographic, psychographic, and behavioral aspects, targeting premium consumers, creative professionals, and urban youth. The targeting strategy emphasizes product quality, design, and symbolic value, while positioning is established as a premium brand supported by an integrated product ecosystem. Survey findings show that ease of access is the most prioritized factor among respondents (40%), followed by information completeness (33%). The overall satisfaction level is categorized as moderate, with a mean score of 3.67. These findings suggest that Apple’s STP strategy has been effective in strengthening brand image among students; however, improvements are still needed, particularly in information delivery and service accessibility. This study is expected to provide practical insights for businesses and educational institutions in developing marketing strategies aligned with young consumer characteristics.
Pengaruh Kecepatan Mata Pisau dan Jumlah Bahan Terhadap Waktu Produksi Cabai Bubuk Pada Mesin Disc Mill FFC15
One of the most profitable horticultural crops, but it spoils quickly due to its high water content. Processing chili peppers with a disc mill into chili powder is a great way to increase the added value of the product while extending its shelf life. The purpose of this study was to determine how the blade rotation speed and amount of material affected the production time of chili powder in an FFC15 Disc Mill. The blade rotation speed varied between 2100 rpm and 3500 rpm, and the amount of material varied between 5% and 500 g. The data were analyzed using statistical analysis to determine the effect of each component and their relationship with each other. The results showed that the blade rotation speed and the amount of material had a significant effect on the production time of chili powder. However, the relationship between these two factors did not have a significant effect. The best operating conditions were achieved with 500 grams of material and a speed of 3500 rpm, which resulted in the fastest production time of 4.367 minutes.
Tingkat Kepatuhan dan Tantangan Pelaksanaan Reklamasi serta Pascatambang IUP OP Batu Andesit di Kabupaten OKU Timur
Mining of rocks, particularly andesite, in East OKU Regency provides significant economic contributions but generates environmental impacts that require rehabilitation through reclamation and post-mining management. This study aims to evaluate the compliance level of Production Operation Mining Business License (IUP OP) holders with these obligations and to identify challenges in their implementation. A descriptive quantitative and qualitative approach was employed, with primary data collected through interviews and field observations related to reclamation and post-mining plans, as well as the placement of guarantees. Secondary data included IUP licensing documents, legislation, and guidance letters from the Energy and Mineral Resources Office of South Sumatra Province. Quantitative analysis categorized compliance levels, while qualitative analysis examined challenges and guidance strategies. The results indicate variations in IUP OP holders’ compliance; some have prepared documentation and placed guarantees, but delays and lack of continuity were observed. Major challenges include profit-oriented approaches, limited technical and environmental understanding, and limited permit duration. Guidance strategies, supervision, guarantee management, provision of technical experts, and community empowerment proved essential. These findings have implications for enhancing compliance, sustainable post-mining planning, and responsible mining practices.
Analisis Penggantian Exhaust System terhadap Performance Engine type 2NR-VE
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.
Optimalisasi Sistem Kendali PID Pada Pembangkit Listrik Tenaga Surya Untuk Stabilitas Tegangan
This research focuses on optimizing the control system to improve voltage stability in a 10 kW Solar Power Plant (PLTS) located in a tropical region. The main issue addressed is voltage fluctuation caused by the intermittent nature of solar radiation (200–1200 W/m²) and temperature variations (20–50°C), which result in up to 12% overshoot in the inverter. The proposed method implements a Proportional-Integral-Derivative (PID) controller optimized using the Particle Swarm Optimization (PSO) algorithm with real-time irradiation input data. The research integrates a 100 Hz digital low-pass filter to mitigate sensor noise under low irradiation conditions. Simulation results show that the PID-PSO system successfully reduces overshoot from 12.1% to 4.2% under high irradiation, and decreases settling time from 0.62 seconds to 0.31 seconds. The digital filter effectively reduces measurement deviation from 7.2% to 2.8% at 200 W/m² irradiation. The PSO optimization achieved optimal convergence within 37 iterations with an Integral of Time-weighted Absolute Error (ITAE) value of 0.18. This study concludes that the implementation of PID-PSO with a digital filter significantly enhances the voltage stability of the PLTS by 20.3% compared to conventional PID control and is ready to be applied in tropical-region smart grid systems.
Evaluasi Angkutan Pelajar di Kota Singkawang
The city of Singkawang has experienced rapid population growth, leading to an increase in the number of students. On 17 September 2024, the Singkawang City Transportation Agency implemented a free revitalized Student Transport service to reduce the number of traffic accidents involving students. The aim of this study is to identify service and respondent characteristics, evaluate operational management, and assess performance and user satisfaction using the IPA and CSI methods, as well as Vehicle Operating Costs (VOC). The research employs a descriptive quantitative method by analyzing descriptive statistical data. Data were obtained from field observations, interviews, and surveys of 400 student respondents (146 users and 254 non-users). The results show that the student transport operates with two vehicles serving the North and East Singkawang routes. The load factor for outbound trips is 22%–32% and for return trips is 11%–12%, with travel times of 68–85 minutes, average operating speeds of 20–22 km/hour, and circulation times of 68–85 minutes. Based on the IPA analysis, the indicators in quadrant D require socialization regarding the functions and use of the interior of the student transport. The CSI result shows a score of 99.79% (very satisfied). The annual VOC amounts to IDR 292,905,814 (East Singkawang) and IDR 282,020,390 (North Singkawang). In conclusion, this service is satisfactory but still requires socialization to enhance its attractiveness and effectiveness.
Influence of Epoxy Resin on the Compressive Strength of Laminated Bamboo Short Columns
The use of laminated bamboo columns as alternative building materials has attracted increasing attention, particularly as a substitute for wood in construction. Bamboo lamination techniques enable the production of structural materials with tailored mechanical properties. Numerous previous studies have investigated the compressive strength of laminated bamboo short columns subjected to various treatments. This study aims to evaluate the compressive strength and failure patterns of laminated bamboo short columns under compression loading. The experimental program included physical and mechanical characterization of bamboo, followed by compression testing of laminated bamboo short columns with dimensions of 10 cm × 10 cm × 30 cm. Three treatment variations were examined: untreated laminated columns, epoxy resin–coated columns, and steel plate–reinforced columns. The results indicate that untreated laminated bamboo columns exhibited an average compressive strength of 28.044 MPa, with cracking concentrated at the top of the column. Epoxy resin–coated laminated bamboo columns achieved an average compressive strength of 28.774 MPa, showing crack formation distributed across several regions of the column. Steel plate–reinforced columns demonstrated the highest average compressive strength of 31.138 MPa, with failure localized in the region between the steel plates. These findings provide valuable insights into the effectiveness of different treatment methods in enhancing the compressive performance and failure characteristics of laminated bamboo columns.
Sistem Monitoring dan Pakan Otomatis pada Ikan Lele Berbasis Mikrokontroler ESP32
Catfish farming is one of the fisheries areas with great potential in Indonesia. However, the problem of feed efficiency, use of probiotics, and air temperature control are still the main obstacles that affect the health and growth of fish. This study aims to design and implement an automatic system that can regulate the provision of feed and probiotics and control and control air temperature directly using the ESP32 microcontroller. This system has several important components, such as the ESP32 microcontroller as a control center, servo motors for feed and probiotic distribution, and DS18B20 temperature sensors to monitor air temperature. All components can be controlled and viewed through an IoT-based application with a Wi-Fi connection or applications such as Telegram. This trial aims to determine whether this system can provide feed and probiotics according to the specified time, and maintain air temperature in the optimal range (28°C–40°C) for catfish growth. In this way, the system is expected to increase efficiency in catfish farming automatically, reduce the need for human labor, and minimize errors in pond management.
Pengaruh Struktur Mikro terhadap Sifat Mekanik Material Logam
The objective of this study is to comprehensively examine and analyze the influence of microstructure on the mechanical properties of metallic materials. Microstructure is known to play a crucial role in determining the mechanical behavior of metals; therefore, a thorough understanding of this relationship is essential for the development of engineering materials. This study adopts a systematic literature review approach, employing descriptive analysis and meta-analysis of recent scientific publications obtained from various reputable academic databases. The analysis results indicate that microstructure is a significant determinant of the mechanical characteristics of metallic materials, including strength, ductility, and resistance to deformation. The most influential microstructural parameters include grain size, phase distribution, crystallographic orientation, dislocation density, and the presence and characteristics of precipitates. Among these parameters, grain size has been shown to be the most dominant factor. The Hall–Petch strengthening mechanism demonstrates that grain refinement can increase the tensile strength of materials by approximately 200 to 300 percent. In addition, materials with multi-phase microstructures, such as dual-phase steels and TRIP steels, exhibit an excellent combination of strength and ductility compared to single-phase materials. Based on the meta-analysis results, each metallic material system exhibits a trade-off between strength and ductility, whereby an increase in strength is generally accompanied by a reduction in ductility. These findings indicate that achieving an optimal combination of mechanical properties for specific application requirements necessitates a comprehensive and integrated microstructural engineering approach.
Peran Material Daur Ulang dan Biopolimer Dalam Penerapan Circular Economy di Industri Manufaktur
The analysis methods used in this study include a case study on the use of closed-loop recycling and an evaluation of biopolymer performance across various industries, both of which are important components in the transformation of the manufacturing industry toward a circular economy. The research findings indicate that recycled materials can reduce carbon emissions by thirty to fifty percent and save production costs by fifteen to twenty-five percent. Artificial intelligence-based sorting technology improves sorting efficiency to 95 percent, and closed-loop recycling maintains the mechanical properties of materials up to 90 percent after four cycles. The degradation rate of biopolymers like PLA and PHA reaches 60-80% within six months, although production costs are still 2-3 times higher. The integrated approach increases resource efficiency by 45% and reduces waste by 60%. To achieve successful implementation, Extended Producer Responsibility (EPR) policies, strategic infrastructure investments, and collaboration from various parties thru the triple helix model must work together.
Penerapan Model Pembelajaran Problem Based Learning pada Kompetensi Sistem Pengapian untuk Meningkatkan Hasil Belajar Siswa SMKN 1 Katapang
This study aims to determine the effect of implementing the Problem-Based Learning (PBL) model on student learning outcomes in the Ignition System competency at SMKN 1 Katapang. The background of this study stems from the low understanding of students regarding the ignition system material due to the dominant use of the Teacher-Centered Learning (TCL) model, which tends to make students passive and only memorize concepts without understanding the overall working process. PBL is considered more relevant because it emphasizes real problem-solving, critical thinking, collaboration, and analysis according to constructivist theory. The method used is a quasi-experiment with a Nonequivalent Control Group Design. The research subjects consist of two classes of 11th-grade Light Vehicle Engineering students: an experimental group using the PBL model and a control group using TCL, with a total population of 70 students. Data collection was done through pretests and posttests using a validated multiple-choice objective test instrument. Data analysis includes comparing the learning outcome improvements of both groups to determine the effectiveness of PBL. The results show a more significant improvement in learning outcomes in the class using the PBL model compared to the TCL class. This proves that the implementation of PBL is effective in improving analysis skills and diagnostic skills in the ignition system. Therefore, PBL is recommended as a more suitable teaching model for practice-based subjects in vocational schools, especially in automotive electrical competencies.
Implementasi Fuzzy Logic Control Metode Mamdani pada Pengatur Nilai Ph Air dan Nutrisi Hidroponik
In this study, a device was designed and implemented to control the water pH and nutrient density (concentration) in a hydroponic system using the Mamdani method of fuzzy logic, thus maintaining nutrient solution parameters within an optimal range for plant growth. This system relies on three input values ​​obtained from a water pH sensor, a nutrient TDS sensor, and a flow meter. These three sensors are used to control four peristaltic motors, each of which functions to increase and decrease the pH and nutrient levels in the solution. The speed of the peristaltic pump motor, when the water pH is set at 6.5 and the nutrient concentration is set at 700 ppm, is influenced by the difference between the sensor reading and the set point. The greater the difference, the higher the peristaltic pump motor speed. Conversely, the smaller the difference between the sensor reading and the set point, the lower the peristaltic pump motor speed. Furthermore, the amount of water flowing through the pipe also influences the peristaltic pump motor speed.
Analisis Kebutuhan Kapal Tongkang dan Tugboat pada Distribusi Crude Palm Oil (CPO)
This study aims to analyze the need for barges and tugboats in distributing Crude Palm Oil (CPO) in the West Papua region. The analysis is conducted based on three main aspects: the balance of supply and demand, ship operational costs, and shipping time, to determine the most efficient mode of sea transportation. The research method used is a quantitative approach by processing CPO distribution data owned by PT Kurhanz Trans in 2024. The results show that the combination of a 240-foot barge with a 5,000 HP tugboat is the most optimal alternative. This combination is able to balance cargo capacity, operational cost efficiency, and shipping time. The total operating cost of a 240-foot barge is recorded as lower than a 230-foot barge, with the same shipping time of 70 hours for a distance of 140 nautical miles. Thus, the 240-foot barge can be recommended as the best alternative to support the smooth distribution of CPO in the West Papua region efficiently and economically.
Estimasi Sumberdaya Batubara Menggunakan Metode Kriging di PT. Inti Bara Perdana, Taba Penanjung
This study aims to estimate coal resources using the kriging method at PT. Inti Bara Perdana, Taba Penanjung, Bengkulu. Geostatistical analysis was applied to evaluate spatial variability of coal quality parameters, including total moisture (TM), inherent moisture (IM), ash content (ASH), volatile matter (VM), fixed carbon (FC), and calorific value (CV). The research utilized drilling data with an average spacing of 80 meters. Variogram modeling was conducted using SGeMS software, employing spherical models to determine nugget, sill, and range parameters. The results show a low nugget effect (0%) indicating strong spatial continuity. The obtained ranges vary between 180–1296 meters depending on the parameter. Blo./ck kriging estimation was performed using block dimensions of 25 × 25 × 8 meters and a coal density of 1.3 ton/m³. The total estimated coal resource up to an elevation of 230 m is 253,500 tons. These findings demonstrate that kriging provides reliable resource estimation and supports mine planning optimization. This research contributes to improving coal resource evaluation accuracy and operational decision-making in open-pit mining.
Pemetaan Riset Grafit sebagai Adiktif dalam Biodiesel di Asia Tenggara dan Peluang untuk Indonesia Menggunakan Meta Analisis Review
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.
Pembuatan Aplikasi Sistem Electronic Contractor Safety Management System (E-CSMS) Berdasarkan Pedoman CSMS PT. XYZ
PT. XYZ faces administrative challenges in implementing the Contractor Safety Management System (CSMS), which has been managed manually from risk assessment and pre-qualification to contractor selection resulting in validation delays, document duplication, and limited monitoring. This study aims to: (1) identify the constraints of the manual CSMS at PT. XYZ; (2) design an electronic-CSMS (e-CSMS) application tailored to internal user needs; (3) analyze the contribution of e-CSMS to document management effectiveness; and (4) evaluate the design's alignment with the Occupational Health and Safety Management System (SMK3) principles as per Government Regulation No. 50 of 2012. The method employed is Research and Development (preliminary stage) using a descriptive qualitative approach through interviews, observations, and document studies. The design results include: (i) a unified digital form integrating procurement data input, risk assessment entries (severity and probability), and document upload and assessment for pre-qualification/selection in a single workflow; (ii) a monitoring dashboard with filtering and export functions; and (iii) internal access settings within PT. XYZ's HSSE portal. Functionally, this design addresses the main bottlenecks of the manual process by creating a more concise, structured, and documented verification workflow, thereby making document management more efficient and traceable. In terms of compliance, e-CSMS supports the implementation of SMK3 elements in the administrative domain of policy establishment, planning, and execution of OHS plans through consistent recording and verification mechanisms. Development recommendations include expansion to field implementation phases, automation of risk-level calculations, and an option for preliminary data entry by contractors with final verification remaining with the internal team.
Evaluasi Kerusakan Lapisan Permukaan Jalan dengan Metode PCI dan Tindakan Preservasi di Jalan Pemda, Kapur, Kec.Sungai Raya, Kab.Kubu Raya
Pemda Road in Kapur Village, Sungai Raya District, Kubu Raya Regency, West Kalimantan is a district road that functions as an alternative route connecting Tanjung Raya II Road and Kapur Village Main Road. Along with increasing traffic loads and limited maintenance, this road section has experienced various surface pavement distresses that reduce driving comfort and compromise road safety. This paper seeks to detect the types and severity levels of pavement damage and to determine appropriate preservation actions using the Pavement Condition Index (PCI) method. The research method involved a visual field survey by dividing the road into several segments, identifying damage types and severity levels, calculating PCI values, and determining suitable preservation measures based on the Asphalt Institute MS-17 guidelines. The results indicate that the flexible pavement section has a PCI value of 21.643, classified as very poor, with dominant damages consisting of potholes and edge cracking. Meanwhile, the rigid pavement section shows a PCI value of 94.960, which falls into the excellent category. The results of this research are anticipated to facilitate decision-making in determining maintenance priorities and road preservation strategies to improve pavement performance and extend service life.
Optimalisasi Penjadwalan Perbaikan Kapal X di PT XYZ Menggunakan Critical Path Method
Punctuality is a crucial factor in ship repair projects because it directly affects operational efficiency, project costs, and the utilization rate of shipyard facilities. Delays in work completion can lead to increased costs, disruption of ship operational schedules, and decreased shipyard productivity. Therefore, this study aims to analyze and optimize the repair scheduling of Ship X at PT XYZ using the Critical Path Method (CPM). The research data were obtained from the actual project schedule compiled using Microsoft Project software, including the duration of each activity and the dependency relationships between tasks. The analysis results show that the project has one main critical path with a total duration of 74 hours. Most activities are on the critical path with a float value of 0 hours, while the Non-Destructive Test Penetrant Testing activity has a time slack of 1 hour. The application of the CPM method has proven effective in identifying critical activities, improving schedule control, and supporting managerial decision-making in optimizing ship repair projects.
Analisis Desain Perkerasan Jalan Kaku dengan Menggunakan Metode Bina Marga (MDPJ 2024 dan MKJI 1997)
This study analyzes the design of the width and rigid pavement of the road on Sp. Brongkos – Ngembul, Kesamben District, Blitar Regency, along 4.5 km with an existing road width of 5 meters, rumija 16.8 meters. The surrounding area includes forestry, residential, plantation, industrial, and Jolosutro Beach tourist access, with increased traffic density during the holiday season and industrial operations. The method used is descriptive quantitative based on LHR and CBR data. The calculation of lane width using MKJI 1997 (Indonesian Road Capacity Manual) shows the need for widening of 3 meters per lane and 2 meters of shoulder. The rigid pavement design using the MDPJ 2024 method (Road Pavement Design Manual) consists of a layer of coarse-grained soil embankment, class A aggregate, lean concrete, and structural concrete with a thickness of 200 mm, 200 mm, 150 mm, and 200 mm, respectively. With the JPCP design, for the tie bar connection reinforcement with a diameter of 16 mm, a length of 700 mm, a distance of 70 cm, and a dowel with a diameter of 28 mm, a length of 45 cm, and a distance of 30 cm.
Pengembangan Media Pembelajaran Sistem Rem Hidrolik Sepeda Motor Untuk Meningkatkan Minat Belajar Mahasiswa Pendidikan Teknik Otomotif Universitas Muhammadiyah Purworejo
This study aims to develop learning media for motorcycle hydraulic brake systems through three main aspects. First, it examines the development procedures covering the planning, design, and implementation stages. Second, it evaluates the feasibility of the developed media for Automotive Engineering Education students at Muhammadiyah University of Purworejo in terms of effectiveness, ease of use, content relevance, and visual and functional appeal. Third, the study analyzes the effect of the media on improving students’ learning motivation, including learning interest, active participation, and persistence in understanding automotive materials. The research employed a Research and Development (R&D) approach involving purposively selected students from the Automotive Engineering Education program. Data were collected using questionnaires to assess media feasibility and student responses. Data analysis consisted of a normality test, homogeneity test, and a t-test to identify significant differences between pre- and post-intervention learning outcomes. The results indicate that the developed learning media is feasible and effective, and has a positive impact on students’ learning motivation and learning outcomes at Muhammadiyah University of Purworejo.
Perancangan Prototype Pembangkit Listrik Tenaga Mikro Hidro Berbasis Turbin Crossflow Skala Laboratorium Menggunakan Metode VDI 2221
The energy that is stored in water can be used to generate electricity by taking advantage of the potential energy available, like the energy from waterfalls and the movement of flowing water. Micro-hydropower plants (PLTMH) are one solution to address the energy crisis, particularly in electricity. VDI 2221 is a method that German engineers use as a guideline when designing construction projects. The VDI (Verein Deutsher Ingeneure or German Engineers Association) design process involves several stages: task description, design concept determination, physical design, and detailed design. Based on the solution principle matrix table, 3 variants were obtained, each of which has criteria. Of the 3 variants that have been evaluated, variant 2 was obtained with results that met the requirements. The cost analysis table shows that the total cost for designing a prototype test equipment for a micro-hydroelectric power plant (PLTMH) based on a laboratory-scale crossflow turbine is Rp 10,032,000. This cost includes instrumentation, control and electrical panels, measuring instruments, pipe instruments, frame and casing, and unforeseen costs.
Analisis Tenaga Kerja dalam Meningkatkan Produktivitas Pekerjaan pada Pembangunan Perumahan Palm Vista Residence
Labor productivity is a critical factor in construction project success as it directly affects time, cost, and work quality. In the Palm Vista Residence housing development project, delays in ground floor structural works indicate suboptimal human resource performance. This study aims to analyze labor productivity levels, identify factors influencing productivity, and formulate strategies to improve productivity in sloof beams, columns, and floor slab works. The research employs a quantitative approach with descriptive-analytical methods through field observations, questionnaires, and interviews. Labor productivity is measured using the work sampling method and the Labour Utilization Rate (LUR), while influencing factors are analyzed using multiple linear regression. Strategy prioritization for productivity improvement is determined using the Analytical Hierarchy Process (AHP). The results show that labor productivity is at a moderate level and is significantly influenced by work experience, managerial aspects, and coordination and planning. The priority strategies include improving worker competence and strengthening project management practices. These findings are expected to provide practical guidance for construction labor management to enhance efficiency and ensure timely project completion.
Analisa Pengaruh Variasi Pengelasan Tungsten Inert Gas (TIG) terhadap Sifat Material Aisi 304 pada Sudu Runner Turbin Francis
This study aims to analyze the effect of Tungsten Inert Gas (TIG) welding parameter variations on the mechanical and metallurgical properties of AISI 304 austenitic stainless steel, which is widely used in construction and industrial applications due to its excellent corrosion resistance and joint strength. The research focuses on identifying the optimal welding current to minimize welding defects and enhance joint structural integrity. Welding current was varied at three levels, namely 100 A, 125 A, and 135 A, while other parameters such as welding speed, argon shielding gas flow rate, and electrode type were kept constant. Mechanical properties were evaluated through Micro-Vickers hardness testing conducted in the weld metal, Heat Affected Zone (HAZ), and base metal, as well as tensile testing to determine ultimate tensile strength and elongation. In addition, non-destructive testing using the dye penetrant method was performed to detect surface welding discontinuities. Metallographic analysis was carried out using optical microscopy following an etching process to observe grain morphology, grain size, and the formation of microstructural phases. The results are expected to demonstrate a correlation between increased heat input due to higher welding current and changes in mechanical properties and microstructure, particularly in the HAZ. This study provides practical guidance for determining optimal TIG welding parameters for AISI 304 to achieve high tensile strength, homogeneous hardness distribution, and a stable microstructure resistant to intergranular corrosion.
Rancang Bangun Sistem Proteksi Otomatis pada Generator Turbin Gas dari Arus Berlebih dan Drop Tegangan Guna Meningkatkan Keandalan Operasional
Gas turbine generators play an important role in providing electrical energy, especially in the maritime sector, but they are vulnerable to disturbances such as overcurrent and undervoltage, which can cause equipment damage. This study aims to design and test an automatic protection system based on the ESP32 microcontroller with the INA219 sensor to detect current and voltage, as well as a relay as a circuit breaker. The method used is an experimental approach including static and dynamic testing, both with and without a 5W AC lamp load as a simulation of real loading conditions. Test results show that the average sensor reading error is 2.65% for current and 1.76% for voltage, which is still within the ±3% tolerance limit. The system is able to disconnect the load when any parameter exceeds the protection threshold, although there are slight inconsistencies in the relay response due to sensor reading fluctuations. In conclusion, this automatic protection system is proven to be 85% accurate and responsive in maintaining the operational reliability of the gas turbine generator, making it applicable as a preventive solution against electrical disturbances in marine environments.
Pengaruh Implementasi Sistem Mini-QHSE terhadap Tingkat Risiko K3 dan Kesejahteraan Pekerja UMKM
This study aims to test the effectiveness of the implementation of a simplified Mini-QHSE (Quality, Health, Safety, Environment) system in improving working conditions at the Syams Handicraft woven craft MSME in Pati Regency, Central Java. The study used a quantitative method with a one-group pretest–posttest design involving 47 workers as respondents. Data collection was conducted through questionnaires and observations before and after the twelve-week intervention. The results showed that the implementation of the Mini-QHSE system was able to significantly reduce the level of occupational safety and health risks and significantly improve worker welfare. Further analysis revealed that the Mini-QHSE system made a significant contribution to variations in OHS risks and worker welfare. The dimension of safe work procedures proved to be the most influential factor in reducing work risks, while the training aspect was the main factor in improving worker welfare. Based on these findings, it can be concluded that the Mini-QHSE system designed according to the capacity and characteristics of MSMEs is effective in creating a safer and more prosperous work environment. This model has the potential to be applied to similar MSMEs with contextual adjustments as a practical solution in managing quality, safety, and occupational health in the micro-business sector.
Evaluasi Risiko Postur Kerja pada Aktivitas Lifting Menggunakan Push Pull Stick Berdasarkan Metode REBA
Lifting activities are an essential part of manual material handling across various industrial sectors and constitute a primary source of ergonomic risk exposure when performed with inappropriate work postures. The use of hands-off tools such as push-pull sticks is often implemented to maintain a safe distance between workers and loads and to reduce exposure to line-of-fire hazards. However, the implementation of work aids does not automatically ensure neutral work postures, as push-pull techniques, reach distances, and environmental conditions can still lead to awkward postures. This study aims to evaluate the work posture risk in lifting activities using a fiber-composite push-pull stick based on the Rapid Entire Body Assessment (REBA) method. The research was conducted as an observational analytic field study involving nine workers in tubular pushing and pulling activities. Work postures were documented through direct observation and visual recordings, then assessed using REBA to obtain risk scores, risk categories, and required corrective actions. The results indicate that work postures fall into the medium to high-risk categories, with trunk and shoulder components being the dominant contributors. These findings confirm the need for improvements in work methods, ergonomic training, and strengthening of lifting SOPs to optimize the safety and ergonomic benefits of work aids.