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All Journal Turbo : Jurnal Program Studi Teknik Mesin Jurnal Asiimetrik: Jurnal Ilmiah Rekayasa Dan Inovasi Journal of Applied Sciences and Advanced Technology Jurnal Bakti Masyarakat Indonesia Logic : Jurnal Rancang Bangun Dan Teknologi
Purba, Riki Hendra
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Agriculture, Biological Sciences & Forestry Automotive Engineering Chemical Engineering, Chemistry & Bioengineering Civil Engineering, Building, Construction & Architecture Computer Science & IT Control & Systems Engineering Education Electrical & Electronics Engineering Engineering Industrial & Manufacturing Engineering Mechanical Engineering Social Sciences Other

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Study of Fluid Flow Characteristics In A 90° Pipe Bend With Varying Guide Vane Length Julian, James; Purba, Riki Hendra; Sedeq, Khalees; Wahyuni, Fitri; Junaedi, Thomas
Journal of Applied Sciences and Advanced Technology Vol. 6 No. 3 (2024): Journal of Applied Sciences and Advanced Technology
Publisher : Faculty of Engineering Universitas Muhammadiyah Jakarta

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.24853/jasat.6.3.99-108

Abstract

The influence of guide vane length and Reynolds number was investigated using computational fluid dynamics methods. By using a structured mesh, it is known that the three mesh variations used have been verified using the Richardson Extrapolation method. The validation process also showed quite good results. From this research, it can be seen from the velocity profile trend, which is close to the experimental results from previous studies. Changing the Reynolds number does not significantly change the velocity profile at the outlet bend. However, it can be seen that changes in the Reynolds number impact the fluid flow pattern produced around the pipe bend. It can be seen clearly, especially when the velocity is negative. Changing the length of the guide vane changes the flow pattern quite significantly. It is known that the shorter the guide vane used, the velocity profile will tend towards the outer core. Furthermore, using a guide vane increases the velocity profile at the position -0.3≤r/R≤ -0.06. Using a guide vane has proven to eliminate negative velocity areas on the inner core side of each variation.
Microbubble Measurements using Image Processing with the YOLOv8 Comparison Model Julian, James; Ulhaq, Faiz Daffa; Dewantara, Annastya Bagas; Purba, Riki Hendra; Wahyuni, Fitri; Junaedi, Thomas
Journal of Applied Sciences and Advanced Technology Vol. 6 No. 3 (2024): Journal of Applied Sciences and Advanced Technology
Publisher : Faculty of Engineering Universitas Muhammadiyah Jakarta

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.24853/jasat.6.3.109-116

Abstract

Gas-liquid two-phase is a situation where the gas phase of a liquid coexists together. The presence of gas that forms a region in the liquid environment causes the formation of bubble flow. The parameters of the bubble flow carry important information about the behavior and characteristics of the bubble. This research was carried out by detecting the size and area of the bubble using YOLOv8-based image processing by comparing the model's performance to produce improvements in inference time, increase accuracy, and reduce computational load. Bubble images were collected by adding 0.4 mm copper wire as a comparison to convert mm to pixels; then, the images were labeled and trained with various YOLOv8 models. Confusion matrix, precision and recall are used as comparative evaluation materials for the YOLOv8 model to obtain good model performance. In this study, the AUC of the Precision and Recall curve closest to the value 1 is the YOLOv8m model of 0.990. The comparison results of the matrix evaluation with the best model are the YOLOv8m model with mAP of 99.00% and F1-score of 96.86%. Microbubble measurements are calculated from the output of the YOLOv8 model by converting pixel units to mm. The model used in bubble measurements is the model with the best evaluation results and the model that gets the smallest radius value by considering measurement uncertainty, namely YOLOv8m with a minimum radius of 0.66 ± 0.04 mm..
Erosive Wear Characteristics Analysis of High Chromium White Cast Iron using Finite Element Analysis (FEA) Purba, Riki Hendra; Deva Ihsan Khoirunas; James Julian; Fitri Wahyuni
Jurnal Asiimetrik: Jurnal Ilmiah Rekayasa & Inovasi Volume 7 Number 1 (2025)
Publisher : Fakultas Teknik Universitas Pancasila

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.35814/asiimetrik.v7i1.7476

Abstract

Erosive wear often occurs on heavy machinery operating under extreme conditions. This research utilizes the Finite Element Analysis (FEA) method with the Cowper-Symonds strain rate model to analyze the erosion behavior of high-Cr cast iron (HCCI) under different impact angles and compare it to other materials of different characteristics, such as 6061-T6 Aluminium, GH4720Li Superalloy, and Stainless Steel 304 Annealed. A single particle erosion model was made for this study. The erodent particle size used is 0.7 mm in diameter, with the target material measuring 1 x 1 x 0.5 mm. The particle velocity is kept constant at 25 m/s. Based on the simulation results, it can be known that HCCI performs the best at every impact angle. Moreover, from the model's cross-section, it's evident that the material's stress concentration aligns with the direction of movement of the erodent particle. Therefore, it can be concluded that these factors, along with others such as contact time, plastic strain, and surface deformation lead to variations in surface mechanics.
Investigation of Flap Dimensional Parameters to Improve Hydrodynamic Performance of Oscillating Wave Surge Converter Device Anggara, Rizki Aldi; Julian, James; Wahyuni, Fitri; Purba, Riki Hendra; Toding Bunga, Nely
Jurnal Asiimetrik: Jurnal Ilmiah Rekayasa & Inovasi Volume 7 Number 1 (2025)
Publisher : Fakultas Teknik Universitas Pancasila

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.35814/asiimetrik.v7i1.7911

Abstract

Renewable energy transition is a strategic step in overcoming environmental damage due to fossil fuel exploitation. Ocean wave energy comes with its popularity, considering its advantages in supplying energy continuously and having high energy density. Therefore, technology that can extract other wave energy effectively and efficiently is needed. This study focuses on identification flap geometry to improve the oscillating wave surge converter (OWSC) hydrodynamic performance. Through a numerical approach, the Boundary Element Method (BEM) is applied in three-dimensional flap modeling to accommodate testing the characteristics and performance of the OWSC device. This study identified five different samples: geometry 1, geometry 2, geometry 3, geometry 4, and geometry 5. The results show that the second geometry variation is the most optimal flap dimension parameter. The best proportion is found in the dimensional characteristics parallel to the elevation of the ocean waves to maximize the output torque. Overall, the second geometry performs satisfactorily with an average maximum power achievement of 41.52 Watts at a wave period of T = 1.5s. In addition, the OWSC device with this variation can work at an expansive wave period interval with a maximum CWR efficiency achievement of up to 52.14%.
The Effect of Hydrostatic Pressure on the Performance of Oscillating Wave Surge Converter Prabowo, Anton Dwi; Julian, James; Wahyuni, Fitri; Purba, Riki Hendra; Toding Bunga, Nely
Jurnal Asiimetrik: Jurnal Ilmiah Rekayasa & Inovasi Volume 7 Number 1 (2025)
Publisher : Fakultas Teknik Universitas Pancasila

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.35814/asiimetrik.v7i1.7912

Abstract

The latest energy demand increasingly drives innovation in ocean wave energy technology, including the Oscillating Wave Surge Converter (OWSC). This consider analyzes the impact of water profundity varieties on the execution of OWSCs put on the seabed. The study was conducted numerically using the Boundary Element Method by testing four variations of air depth at wave periods between 1.2 and 2.8 seconds and wave amplitudes of 0.1 meters. The results show that the optimal depth, equivalent to the flap height (D2), produces the highest maximum displacement due to the balance between hydrostatic pressure and wave energy the flap receives. Conversely, depths that are too shallow (D1) or too deep (D4) result in smaller displacements due to the instability of the movement in shallow air and the attenuation of wave energy in deep air. In addition, more extended wave periods tend to decrease the changing cycle frequency but increase the symmetry of the flap movement at a certain depth.
Utilization of Single and Double Orifice Plates in Pipe Inner Flow Structure by Computational Method Naufal, Ridwan Daris; Julian, James; Wahyuni, Fitri; Purba, Riki Hendra; Toding Bunga, Nely
Jurnal Asiimetrik: Jurnal Ilmiah Rekayasa & Inovasi Volume 7 Number 1 (2025)
Publisher : Fakultas Teknik Universitas Pancasila

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.35814/asiimetrik.v7i1.7913

Abstract

The orifice plate is a device that disrupts the flow in the pipe. The disturbed flow results in the formation of flow structures. The flow structure formed can be utilized for several applications such as multi-fluid mixing and microbubble generator. Using orifice plates to utilize the flow structure results in more significant pressure loss. This study aims to identify the characteristics of the flow structure generated by single and double orifice plates with 1D and 2D spacing at various Reynolds numbers, namely Re = 1×104, 5×104, 1×105, and 5×105, as a basis for application in these various applications. The results show that single and double orifice plates can produce flow structure phenomena such as recirculation and vortex regions. The recirculation area is formed smaller in the double orifice plate due to the flow that is separated faster to converge back to the pipe wall but broader so that the flow of the orifice plate is narrower. Increasing the applied Reynold's number causes the separated flow to reconnect to the pipe wall faster, resulting in a smaller recirculation area. Double orifice plates are more suitable for applications that require a certain degree of mixing or pressure distribution, but with a consequent more significant pressure loss. Meanwhile, single plates can be used for simple needs with little pressure loss.
The Analysis of Banana Slices Machine Frame Using Computational Method Akmal, Reza Najmi; Julian, James; Wahyuni, Fitri; Purba, Riki Hendra; Toding Bunga, Nely
Jurnal Asiimetrik: Jurnal Ilmiah Rekayasa & Inovasi Volume 7 Number 1 (2025)
Publisher : Fakultas Teknik Universitas Pancasila

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.35814/asiimetrik.v7i1.7914

Abstract

The culinary industry, especially banana chip processing, dramatically supports the economy of micro and small enterprises (MSMEs) in Indonesia. However, the traditional process is time-consuming, especially at the cutting stage. The banana-slicing machine is designed to speed up this process with consistent and efficient cuts. This study analyzes the performance of the banana-slicing machine frame by testing variations in loading (20 N to 200 N) and frame materials, namely Low Alloy Steel, Structural Steel, Stainless Steel, Aluminum Alloy, and Cast Iron, to determine the optimal material. The results showed that Low Alloy Steel is the best material because it has the lowest total deformation, equivalent stress, and strain energy, reflecting high stiffness and load efficiency. With an elastic modulus of 212.5 GPa and an economical price ($1.3–1.5/kg), this material offers the best balance in terms of technical and economics. Structural steel also performed well but was slightly lower than low alloy steel. In contrast, Aluminum Alloy has the highest deformation and strain energy, making it less suitable for this application. Overall, Low Alloy Steel is an ideal choice to improve the efficiency and reliability of the banana-slicing machine.
Comprehensive Hydrodynamic Analysis of Oscillating Flapping Mechanism for Enhanced Wave Energy Converter Technology Aldi Anggara, Rizki; Julian, James; Wahyuni, Fitri; Purba, Riki Hendra
TURBO [Tulisan Riset Berbasis Online] Vol 14, No 1 (2025): TURBO : Jurnal Program Studi Teknik Mesin
Publisher : Universitas Muhammadiyah Metro

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.24127/trb.v14i1.3786

Abstract

The comprehensive utilization of renewable energy stands as a national priority within Indonesia's strategic framework aimed at achieving the net zero emissions target by 2060. Indonesia, a nation in which nearly 70% of its territory is comprised of oceans, possesses significant potential in wave energy as a renewable energy source. This sector presents promising opportunities for development and investment. This study focuses on the three-dimensional hydrodynamic study of Wave Energy Converter (WEC) technology based on oscillating flapping through a numerical approach. The findings of the characteristic test demonstrate that the oscillating flapping device exhibits a response characterized by a deviation in the oscillating tilt angle. The direct impact of ocean waves causes the flap to shift from its equilibrium position and continuously move back and forth with a particular frequency. The dynamics working on this device show a correlation between wave input and the response that occurs. The response parameters, including maximum angular deviation, average speed, and torque, have a similar trend to changes in wave period. The influence of ocean wave activity is observed to increase within the low wave period zone up to a designated period threshold. Overall, the oscillating flapping device demonstrates enhanced performance in low wave conditions. The average maximum output power is capable of reaching 1.5 Watts on A1, 3.5 Watts on A2, and 4.5 Watts on A3.
SOSIALISASI RISIKO LIMBAH MINYAK JELANTAH DAN SOLUSINYA Wahyuni, Fitri; Nisa, Rasya Aulia Nathania; Julian, James; Lumbantoruan, Regina Natalindah; Mahdhudhu, Fathin Muhammad; Purba, Riki Hendra; Armadani, Elvi
Jurnal Bakti Masyarakat Indonesia Vol. 8 No. 1 (2025): Jurnal Bakti Masyarakat Indonesia
Publisher : Lembaga Penelitian dan Pengabdian kepada Masyarakat, Universitas Tarumanagara

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.24912/jbmi.v8i1.34381

Abstract

Used cooking oil is cooking oil that is no longer suitable for use because it has undergone changes in physical and chemical properties during the frying process. Used cooking oil is a hazardous and toxic waste; consuming it can cause negative impacts on health and disposing of it carelessly can cause environmental pollution. However, public knowledge about the dangers and impacts of used cooking oil is still minimal. A study showed that there are still many people who dispose of used cooking oil on the ground and waterways. Therefore, the activity designed by the PKM team of Universitas Pembangunan Nasional Veteran Jakarta aims to increase public knowledge about the dangers and impacts of used cooking oil and provide solutions to reduce the pollution of used cooking oil waste. This activity was carried out in the Grand Pakis Residence housing complex using socialization and training methods. In this activity, the PKM team invited representatives from the Jalantara foundation as speakers to explain the impact of used cooking oil on the environment and health to the community. Not only that, the community was also given a training on processing used cooking oil into other products as a solution to reduce used cooking oil waste. The result of this activity is that the knowledge of residents about the dangers of used cooking oil for the environment and health has increased by 80.95%. In addition, the residents also know how to reduce used cooking oil by turning it into useful products such as soap.
Comprehensive Analysis on the Influence of Flap Width on the Hydrodynamic Parameters of OWSC Devices Nisa, Rasya Aulia Nathania; Julian, James; Wahyuni, Fitri; Purba, Riki Hendra; Mahdhudhu, Fathin Muhammad; Armadani, Elvi
Logic : Jurnal Rancang Bangun dan Teknologi Vol. 25 No. 3 (2025): November
Publisher : Unit Publikasi Ilmiah, P3M, Politeknik Negeri Bali

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.31940/logic.v25i3.201-209

Abstract

The growing need for renewable energy has driven significant interest in harnessing ocean wave power, particularly through Oscillating Wave Surge Converters (OWSCs). This study focuses on examining the effect of flap width on the hydrodynamic capacity of an OWSC, as flap geometry plays a crucial role in energy capture efficiency. A numerical methodology utilizing the Boundary Element Method (BEM) was employed to assess hydrodynamic parameters across both temporal and frequency domains. Five flap width variations were tested under regular wave conditions with different periods, while mesh independence and validation against experimental data ensured accuracy. The results in the time domain revealed a direct correlation between flap width and angular deviation, velocity, torque, and power output, although wider flaps exhibited less stability due to increased inertia. Frequency domain analysis indicated that each flap width had a distinct resonant peak, with narrower flaps performing best at shorter periods and wider flaps at longer ones. Notably, moderately sized flaps (W2 and W3) achieved the highest efficiency, with Capture Width Ratios exceeding 70%, outperforming wider flaps despite their larger surface area. These findings highlight the importance of optimized flap width for efficient and reliable OWSC design.
Co-Authors Akmal, Reza Najmi Aldi Anggara, Rizki Anggara, Rizki Aldi Deva Ihsan Khoirunas Dewantara, Annastya Bagas Elvi Armadani Fitri Wahyuni Fitri Wahyuni James Julian James Julian Junaedi, Thomas Lumbantoruan, Regina Natalindah Mahdhudhu, Fathin Muhammad Naufal, Ridwan Daris Nisa, Rasya Aulia Nathania Prabowo, Anton Dwi Sedeq, Khalees Toding Bunga, Nely Ulhaq, Faiz Daffa