Analysis of Power Transformer Core Retaining Plate Damage During Ship Transportation Using Response Spectrum Method: Analisis Kerusakan Pelat Penahan Inti Transformator Daya Saat Transportasi Kapal Laut Menggunakan Metoda Response Spectrum

Inti transformator daya diletakan di dalam tangki dengan kondisi pressfit 4 sisi di bagian dasar  tangki dan 4 bagian sisi atas ditopang dari 4 arah terhadap gerakan longitudinal - transversal kemudian 2 pedestal  atas inti transformer ditekan dengan tutup tangki di bagian bawahnya. Pada waktu transportasi di laut transformator ini mengalami impak yang terekam sebesar 4.1g, kemudian dengan penyidikan visual terlihat lepasnya pelat penahan dan inti transformator mengalami pergeseran dan kerusakan sehingga  transformator harus dimanufaktur kembali di pabriknya. Analisa dinamika menggunakan metoda elemen hingga (finite element method) diperlukan untuk mengetahui apakah kegagalan penopang sudah terjadi di atas nilai percepatan 1g, sehingga nilai 4.1g adalah benturan inti transformator ke tangkinya. Pemodelan dibuat 3D shell wall modeling orisinil untuk penopang dan tangki, sedangkan model inti transformator bentuknya disederhanakan menjadi kotak shell untuk memudahkan meshing. Parameter input menggunakan High Required Response Spectrum 0.5g dari IEEE std 693-2005 sedangkan parameter dinamik yang diukur adalah besarnya ragam getar, fenomena resonansi dan tegangan (stress) pelat. Hasil data analisa dinamik dengan menggunakan metoda elemen hingga yaitu transformator mengalami resonansi dengan dek kapal, atau bila terjadi impak di badan kapal akibat goyangan ombak di percepatan di atas 1g maka pelat penahan telah mengalami tegangan di atas kekuatan tariknya (Tensile Strength)

Analysis of the Effect of CVT Spring Variation on the Performance of Beat Deluxe Motorcycles

Automatic motorcycles are popular due to their efficiency and flexibility in urban areas. CVT spring modifications are often done to improve performance. This research tested the effect of 1000 RPM (standard), 1500 RPM, and 2000 RPM CVT springs on a Beat Deluxe using a dynotest, observing torque, power, fuel consumption, CVT wear, and engine temperature on 68 kg and 134 kg riders. The results showed that at 3000 RPM, the highest torque was achieved by the 2000 RPM spring (14.04 Nm for 68 kg, 12.84 Nm for 134 kg). The highest power at 4000 RPM was also by the 2000 RPM spring (6.6 HP for 68 kg, 5.9 HP for 134 kg) but with the highest fuel consumption (0.021 l/km for 68 kg, 0.030 l/km for 134 kg). The 1500 RPM spring showed a moderate performance increase with wear and temperature between the 1000 RPM and 2000 RPM springs. The 1000 RPM spring produced the lowest temperature (76.5 ℃), followed by 1500 RPM (79.7 ℃) and 2000 RPM (84.1 ℃), indicating a correlation between spring stiffness and operating temperature

Design and Build Prototype of Field Soil Shear Test Equipment: Perancangan dan Pembuatan Prototipe Alat Uji Geser Tanah

Shear strength analysis testing is a fundamental test in the field of civil engineering. The shear strength of the soil is greatly influenced by the parameters present in the soil, the higher the value of the obtained parameters, the higher the soil strength. To obtain these parameters, we need to conduct one of the soil shear strength tests. The soil shear test that has been conducted in the laboratory involves taking soil samples from the field, transporting them, and then conducting the tests. During the journey from the field to the laboratory, it is highly likely that the sample will undergo changes due to vibrations, shaking, or temperature. Some innovations that have been implemented weigh a maximum of 10kg, are portable and easy to carry, produce accurate test results, and are tested directly in the field. The design of the tool is made in a prototype before the assembly of the tool. The design of the direct shear test tool is made by referring to the standardized testing principles. After the device is assembled, a test is conducted on a soil sample using the standard procedure of the shear test apparatus

Bidirectional Sensor-Based Measurement of PV Output with MPPT Control: An Experimental Pre-Study before PLC Monitoring Integration

This paper presents a preliminary experimental study on the use of an analog bidirectional current sensorfor photovoltaic (PV) systems operated under Maximum Power Point Tracking (MPPT) control. The ultimate goalof this research is to develop a comprehensive monitoring system for energy harvesting from PV systems using aPLC-based platform. As an initial step, this study investigates the behavior of a bidirectional sensor in detectingcharging and discharging processes in an off-grid PV configuration. The sensor is evaluated through experimentalmeasurements of current and voltage outputs, where the bidirectional characteristic provides an indication of thedirection of energy flow—charging when energy is stored in the battery and discharging when energy is supplied tothe load. Data acquisition and visualization are performed using LabVIEW, which allows real-time monitoring andvalidation of sensor performance at specific time intervals. The experimental results provide insights into theaccuracy and reliability of the analog bidirectional sensor under varying operating conditions. The novelty of thisstudy lies in its focus on sensor behavior analysis as a foundation for future PLC-based monitoring systemdevelopment. By validating sensor performance through this pre-study, the research ensures that reliable data canbe obtained for subsequent integration into a real-time monitoring and control system for PV energy harvestingapplication

Experimental Study of Bifacial Solar Panels with Reflective Surface Variations in Bandung, Indonesia

This study aims to evaluate the performance of bifacial photovoltaic (PV) panels under different reflective surface conditions in a tropical urban environment, specifically in Bandung, Indonesia. Bifacial PV systems offer the advantage of capturing solar radiation from both the front and rear sides, with performance significantly influenced by the surface beneath the panels. The experiment involved three surface types: asphalt, untreated paving blocks, and paving blocks coated with white paint. Each panel was installed at a fixed 8° tilt facing north, and data were collected from 09:00 to 15:00 local time. The results indicate that the white-painted surface produced the highest power output, reaching up to 410 Watts, followed by paving blocks at 390 Watts and asphalt at 370 Watts. Although all surfaces received a similar radiation pattern, their differing reflectivity affected the amount of radiation reaching the rear side of the bifacial panels. The white-painted surface, characterized by high reflectance, not only enhanced rear-side radiation capture but also maintained a more stable power output after peak solar hours. These findings highlight the critical role of surface reflectivity in optimizing bifacial PV performance and support the strategic use of surface materials in PV system deployment, particularly in tropical climates. This study contributes valuable empirical data to the growing field of bifacial PV applications and offers practical insights for improving energy yield in real-world tropical settings

Simulation of Waste Load Variations on Stress Analysis Results of Incinerator Wheel

An incinerator is a high-temperature waste-burning device with a closed, insulated combustion chamber, designed to minimize environmental impact [1]. Modern incinerators aim to reduce inorganic waste and smoke emissions, particularly in Metro City, Lampung Province [2]. A key component is the wheel, which reduces friction and enhances mobility [3]. This study focuses on designing the incinerator wheel, determining its geometry and material, and analyzing stress, strain, and deformation through simulation [4]. The design process used Autodesk Inventor Professional, while simulations were performed in SolidWorks [5]. Tests were conducted under three load conditions: no load, 250 kg, and 500 kg. The final wheel design measures 150 mm in diameter, 50 mm in width, and 10 mm in thickness, using cast iron. Simulation results show stress, strain, and deformation remain below material limits, even at 500 kg load, confirming the wheel’s safety and reliability for optimal incinerator performance

Chemical Modification of Petung Bamboo Fiber to Hybrid Composites: Modifikasi Kimia Serat Bambu Petung terhadap Komposit Hibrida

This study evaluates the effect of alkali treatment using NaOH solution on the mechanical properties and microstructure of hybrid composites based on epoxy resin reinforced with petung bamboo fiber and fiberglass. Bamboo fibers were immersed in five NaOH concentration variations (0%, 3%, 6%, 9%, 12%) before composite fabrication using the hand lay-up method. Tensile testing was performed according to ASTM D-638 standard and microstructural characterization using Scanning Electron Microscope (SEM). The results showed that 9% alkali treatment produced the best mechanical performance with a tensile strength of 58.68 MPa, elongation of 4.15%, and elastic modulus of 1413.49 MPa. SEM analysis indicated improved fiber-matrix adhesion due to removal of lignin and hemicellulose. Optimal alkali concentration enhanced composite performance, making it a potential candidate for eco-friendly vehicle interior applications

Analysis of Damage to the Induce Draft Fan Component at PLTU PT. XYZ

Damage to the Induce Draft Fan (IDF), will impact to the combustion system which serves to provide Secondary Air to meet the air needs of the combustion system in the furnace in the boiler. There are 2 IDFs in the generating unit which are operated simultaneously or alternately. The purpose of this research is to determine the damage to the IDF so that there is no decrease in power supply to PLN generators. The method used in this study used fishbone analysis. Based on the analysis, the IDF damage occurs due to abrasion on the fan blade which is caused by the blade surface in contact with the abrasive material (Fe2O3) on the flue gas. The malfunctioning of the Electrostatic Precipitator (ESP) causes the abrasive material (Fe2O3) in the flue gas to not flow to the IDF, thus damaging the blad

Analysis of Pitch Angle Optimization on Horizontal Axis Wind Turbine to Increase the Coefficient of Power (Cp) Value by Simulation and Experiment: Analisis Optimasi Sudut Pitch pada Turbin Angin Sumbu Horizontal untuk Meningkatkan Nilai Coefficient of Power (Cp) Secara Simulasi dan Eksperimental

Energi terbarukan merupakan isu yang sangat penting pada saat ini. Penggunaan pembangkit listrik berbahan bakar fosil harus dikurangi secara sistematis agar tidak memberikan pencemaran lingkungan. Turbin angin merupakan salah satu pembangkit listrik energi terbarukan. Namun demikian penelitian tentang turbin angin harus senantiasa ditingkatkan karena turbin angin memiliki efisiensi yang terbatas. Tidak seperti mesin pada umumnya yang mana efisiensinya cukup tinggi. Penelitian ini bertujuan melakukan optimasi sudut pitch pada turbin angin sumbu horizontal untuk meningkatkan nilai coefficient of power (Cp) secara simulasi dan eksperimental. Optimasi ini harus dilakukan agar gaya lift yang terjadi pada bilah turbin angin sumbu horizontal memiliki nilai optimum dengan memperhatikan gaya drag yang terjadi. Sudut pitch pada turbin dibuat bervariasi dari posisi dekat hub sampai dengan posisi tip. Ada tiga jenis variasi yang dilakukan yaitu 200-00, 250-50 dan 300-100. Simulasi dilakukan dengan software Qblade pada tiga jenis variasi itu kemudian dilakukan eksperimen di laboratorium. Hasil simulasi dan eksperimen menunjukkan pada variasi 20-0 memiliki efisiensi paling tinggi dibanding yang lain. Hasil ini merupakan rekomendasi pada proses pembuatan bilah turbin angin sumbu horizontal

The Effect of Time Variation and Number of Fiberglass Layers in the Composite Material Manufacturing Process on Tensile Strength, Bending and Surface Flatness: Pengaruh Variasi Waktu dan Jumlah Lapisan Fiberglass dalam Proses Pembuatan Material Komposit Terhadap Kekuatan Tarik, Tekuk dan Kerataan Permukaan

This research explores the production of fiberglass composite materials using an open mold process with pressing, aiming to overcome the uneven surfaces often produced by the hand lay-up method. Conducted in the Mechanical Engineering laboratories of Universitas Muhammadiyah Sidoarjo (UMSIDA) and Politeknik Negeri Malang, the study tested specimens using tensile testing (ASTM D638 Type I) and flexural testing (ASTM D790), along with surface flatness measurement via a dial indicator. The research varied the number of fiberglass layers (2, 3, and 4) and the pressing duration (3, 4, and 5 hours). Tensile tests showed the best stress and strain with 2 layers of fiberglass and 3 hours of pressing, with the "hours" factor contributing 55.28% to true stress and 45.23% to true strain. Flexural tests indicated the best stress and modulus of elasticity with 4 layers of fiberglass and 4 hours of pressing, with the "hours" factor contributing 31.48% to the modulus of elasticity. Optimal surface flatness was achieved with 3 layers of fiberglass and 4 hours of pressing, with the "hours" factor contributing 38.77%. Optimizing process parameters is essential for improving the quality of molded products and provides a foundation for developing a more efficient pressing method in future composite material productio