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INDONESIA
Journal of Mechanical Engineering Science and Technology
Published by Universitas Negeri Malang
ISSN : 25800817     EISSN : 25802402     DOI : 10.17977
Core Subject : Science, Engineering,
Energy Engineering Industrial & Manufacturing Engineering Materials Science & Nanotechnology Mechanical Engineering
Journal of Mechanical Engineering Science and Technology (JMEST) is a peer reviewed, open access journal that publishes original research articles and review articles in all areas of Mechanical Engineering and Basic Sciences
Arjuna Subject : Teknik (semua kategori) - Teknik Mesin
Articles 168 Documents
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Performance Analysis of Alkaline Fuel Cell with Variation of Potassium Hydroxide Concentration in Electrolyte Solution Alfariz, Mohammad Rifqy; Ilminnafik, Nasrul; Djumhariyanto, Dwi; Hardiatama, Intan; Ibnu, Muhammad Khadafi; Nugraha, Raafi Aditya; Freitas, Domingos de Sousa
Journal of Mechanical Engineering Science and Technology (JMEST) Vol 9, No 1 (2025)
Publisher : Universitas Negeri Malang

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.17977/um016v9i12025p103

Abstract

Alkaline Fuel Cell (AFC) is a green energy conversion tool that converts chemical energy into electrical energy through electrochemical reactions. This research aims to analyze the effect of potassium hydroxide (KOH) concentration variation in electrolyte solution on the AFC performance, using nickel and manganese catalysts. The research methods include experiments using various KOH concentrations to determine the optimal concentration to produce the best AFC performance. The voltage and current produced are measured, as well as the calculation of the electrical power and efficiency of the AFC. The results showed that KOH concentration has a significant influence on the performance of AFC. It was found that the optimal KOH concentration produces maximum electrical power and energy conversion efficiency. The highest alkaline fuel cell performance was found at 70% KOH concentration. In addition, the use of nickel and manganese catalysts was shown to improve the stability and efficiency of AFC. The result makes an important contribution to the development of AFC technology, supporting global efforts towards cleaner and more sustainable energy use. The findings also provide a basis for further innovations in AFC design and materials, as well as their potential in practical applications such as electric vehicles and portable power plants
Surface Analysis of Bacterial Cellulose Membrane Made from Biowaste Added with ZnO Nanopowder Amasda, Naufal Rizky; Suryanto, Heru; Yanuhar, Uun; Aminnudin, Aminnudin; Nusantara, Fajar; Sias, Quota Alief
Journal of Mechanical Engineering Science and Technology (JMEST) Vol 9, No 1 (2025)
Publisher : Universitas Negeri Malang

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.17977/um016v9i12025p281

Abstract

Utilization of pineapple biowaste is important to increase the value added to biowaste and solve the environmental problem. So, the study objective is to synthesize membranes of bacterial cellulose made from pineapple biowaste and characterize the surface morphology and porosity of the membrane after being added with ZnO nanopowder. The study starts with extracting biowaste as a bacterial cellulose culture medium for the fermentation process. The obtained pellicle was crushed and homogenized with the added ZnO nanopowder in the presence of ultrasonic waves. The membrane is dried in the oven. The membrane morphology was monitored using scanning electron microscope and Brunauer–Emmett–Teller analysis. Results indicate that surface morphology more rougher in line with increasing ZnO nanopowder content. The control membrane exhibits the highest surface area (36.9605 m²/g) due to its uninterrupted porous network. The addition of ZnO nanopowder at 2.5% significantly reduces the surface area to 2.9168 m²/g, likely due to nanoparticle-induced pore obstruction. As the ZnO nanopowder concentration increases to 5% and 7.5%, the specific surface area rises to 8.0436 m²/g and 13.7783 m²/g, respectively. This trend suggests that higher ZnO nanopowder loading enhances porosity and introduces additional adsorption sites. The control BC membrane exhibits the highest pore volume and well-defined mesoporosity, which are diminished upon the initial addition of ZnO nanopowder.
Characterization of Bamboo Petung Fiber Reinforced Composites with Environmentally Friendly Enzymes Raharjo, Rudianto; Widodo, Teguh Dwi; Bintarto, Redi; Alamsyah, Fikrul Akbar
Journal of Mechanical Engineering Science and Technology (JMEST) Vol 9, No 1 (2025)
Publisher : Universitas Negeri Malang

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.17977/um016v9i1p165

Abstract

Natural fiber composites are a good choice for many businesses uses because of their better mechanical properties and are friendly environment. Researchers are currently looking into bamboo petung fiber (BPF) and epoxy composites as alternative to synthetic fibers and products made from petroleum. This study's goal is to improve the overall performance of these composites while reducing the need for non-organic materials. This study used the various concentration of bromelain enzyme in BPF to changes the mechanical and physical properties of epoxy composites made from BPF. Composites were characterized the mechanical properties including tensile strength using tensile tester, impact strength using Charpy impact test, bending strength using three point bending methods, and surface morphology observation using scanning electron microscope. This study indicates that BPF composites that have been treated with bromelain enzyme have better mechanical properties. After being treated with bromelain, the BPF composite's tensile strength increase up to 59% with maximum tensile strength of 138.230 MPa, flexural strength increases up to 42% with maximum flexural strength of 135.58 MPa, and impact strength increases up to 64% with maximum impact strength of 4.88 J/m. The bond between the epoxy resin and the BPF makes the composite stronger. These results suggest that combining natural fibers and enzymes can make composite materials that work well and are strong.
Investigation of Drag Force and Downforce on Two Racing Motorcycles in Slipstream Conditions Hanifudin, Muhamad; Jatisukamto, Gaguk; Darsin, Mahros; Kustanto, Muh. Nurkoyim; Saleh, Azmi; Prasetyono, Suprihadi; Sarwono, Catur Suko
Journal of Mechanical Engineering Science and Technology (JMEST) Vol 9, No 1 (2025)
Publisher : Universitas Negeri Malang

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.17977/um016v9i12025052

Abstract

The performance of modern racing motorcycles is greatly influenced by their aerodynamics. Slipstreaming occurs during a race when a rider closely follows another, especially on a straight track. The effect can reduce aerodynamic drag and increase the overall speed of the rider behind. This study investigates the aerodynamic effects of slipstreaming on a racing motorcycle using computational fluid dynamics. This study also considers its effect on both drag force and downforce, which affects motorcycle stability. A 3D CAD model of a racing motorcycle and a rider in a crouching position was used as the object of research. CFD simulations were carried out using the RANS Steady State solver with the k-ω-SST turbulence model. The simulations evaluated the effect of varying distances between motorcycles on slipstream performance, as well as varying motorcycle speeds. The results show the effect on drag force and downforce for the trailing motorcycle. This is due to the shielding effect of the motorcycle in front, which creates a low-pressure zone behind it. Additionally, the turbulence behind the racing motorcycle also affects its downforce. Optimizing the distance between motorcycles in the slipstream allows riders to improve overtaking performance. It also reduces adverse effects on motorcycle stability caused by the slipstream's influence on downforce. Furthermore, it can be used to develop aerodynamic modifications to racing motorcycles that can utilize the slipstream more effectively.
Effect of Thickness of Nanofiber Separator Membrane PAN/PVDF on Supercapacitor’s Performance Agustina, Silvia Nurlaili; Diantoro, Markus; Hartatiek, Hartatiek; Nasikhudin, Nasikhudin
Journal of Mechanical Engineering Science and Technology (JMEST) Vol 9, No 1 (2025)
Publisher : Universitas Negeri Malang

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.17977/um016v9i12025p228

Abstract

Separators in supercapacitors have an important role as intermediaries for ions that pass during the charge-discharge process and affect the performance of supercapacitors. Therefore, a comprehensive study is needed related to separator characteristics, including morphology, pore size, diameter, functional group, and electrochemical performance of separator membranes from PAN/PVDF composites. The separator membrane was synthesized using the electrospinning method with thickness variation (2, 4, 6, 8, and 10 layers), followed by supercapacitor fabrication with coin cell device. The resulting membrane was then characterized by Scanning Electron Microscope (SEM) and Fourier Transform Infrared (FTIR). For the result of supercapacitor fabrication with coin cells, Galvanostatic Charge-Discharge (GCD), Cyclic Voltammetry (CV), and Electrochemical Impedance Spectroscopy (EIS) were carried out to determine supercapacitor performance. FTIR results showed that the PAN/PVDF membrane was successfully composites with the addition of new peaks identified as PVDF and PAN at wave numbers 2243.21 and 881 cm-1. The nanofibers formed have diameters ranging from 319.7 to 339.95 nm. The optimum percentage of electrolyte uptake is obtained at membranes that have 6 layers, which is 318.18% and decreases to 173.68% the thickness is 10 layers. In this study, the optimum supercapacitor performance was obtained in the 6 layers variation with a thickness of 75.91 x 103 nm with a gravimetric capacitance value is 53.36 F/g, the capacity retention is 88.96% after being tested for 500 cycles, the largest curve area of CV, and an ionic conductivity value is 54 x 10-5 S/cm.
Toolpath Motion Strategy and Feed Rate in CNC Milling on Energy Consumption of Machining Process Saputra, Luqman Dwi; Yudiyanto, Eko
Journal of Mechanical Engineering Science and Technology (JMEST) Vol 9, No 1 (2025)
Publisher : Universitas Negeri Malang

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.17977/um016v9i12025p114

Abstract

The use of CNC milling machines to produce components, especially aluminum brackets used for automotive, is one of the advances in the industrial field. The use of CNC milling machines has the advantage of producing processes with speed accuracy, and better workpiece quality than conventional machines. This research investigates energy consumption in the CNC milling process by varying the toolpath motion strategies—Zigzag, Constant Overlap Spiral, Parallel Spiral, and Parallel Spiral Clean Corners—as well as feed rates of 700 mm/min, 800 mm/min, 900 mm/min, and 1000 mm/min. The goal is to find out the best parameters for using energy in the machining process. The material used in this research is Aluminum 6061. The shape tested is a bracket. The simulation was conducted to determine the machining process time using Mastercam software. The simulation results indicate that the Zigzag toolpath motion strategy at a feed rate of 1000 mm/min produces the lowest energy consumption (307.620 Kilojoules) whereas the Parallel Spiral Clean Corners toolpath at a feed rate of 700 mm/min produce the highest energy consumption (457.142 Kilojoules). The selection of appropriate machining parameters has a significant influence on the efficiency of processing time and production costs. By selecting the right toolpath motion strategy and feeding parameters, the manufacturing industry can increase productivity and reduce production costs more effectively.
Steam Supply Evaluation for Carbon Capture and Storage in a Subcritical Coal-Fired Power Plant Hendrayawan, Veri; Raksajati, Anggit; Adisasmito, Sanggono; Juangsa, Firman Bagja
Journal of Mechanical Engineering Science and Technology (JMEST) Vol 9, No 1 (2025)
Publisher : Universitas Negeri Malang

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.17977/um016v9i12025p291

Abstract

The aim of this study is to analyze the implementation of carbon capture and storage (CCS) in coal-fired power plants (CFPP) in Indonesia by determining the reboiler energy demand through steam source analysis. The study uses a representative 3×330 MW subcritical coal-fired power plant (CFPP), with an emission intensity of 1.02 tCO₂/MWh and flue gas CO₂ concentration of 13.8%. CCS modeling shows the reboiler requires about 2.9×10⁹ kJ/h energy, supplied by steam extracted from the plant’s steam cycle. A steam cycle model was developed to evaluate the impact of steam extraction. Potential tapping points analyzed include main steam, cold reheat, intermediate-pressure (IP) extraction, low-pressure to intermediate-pressure LP-IP crossover, and low-pressure (LP) extraction. Main steam extraction with the highest energy content needs the lowest steam mass flow of 355 t/h but causes the highest energy penalty of 57% because of lost electricity production in HP and IP extraction. Cold reheat extraction requires moderate steam flow of 399 t/h and a penalty of 52% but risks overheating reheater tubes. The LP-IP crossover point needs the highest steam flow 414 t/h, yet achieves the lowest net energy penalty at 33.8% with minimal operational risk, making it the most favorable option for CCS integration.
Multiple Input–Single Output (MISO) Framework for Low Velocity Impact Response of Hybrid Gongronema latifolium/S-Glass Fibre Epoxy Composites Okafor, Christian Emeka; Ugwu, Peter Chukwuemeka; Ekwueme, Godspower Onyekachukwu; Akçakale, Nürettin; Nwanna, Emmanuel Chukwudi
Journal of Mechanical Engineering Science and Technology (JMEST) Vol 9, No 1 (2025)
Publisher : Universitas Negeri Malang

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.17977/um016v9i12025p177

Abstract

Sustainable composites are vital for impact-critical aerospace, automotive, and defense applications. This study used Multiple Input–Single Output (MISO) experimental approach to assess how hybrid ratio, mass fraction, and fiber orientation influence the low-velocity impact behavior of Gongronema/S-glass epoxy composites. Gongronema fibers and S-glass were combined with ER-F292 epoxy and molded into ASTM-standard samples. Charpy impact tests measured energy absorption. A 60-run design evaluated input variable combinations, and Multiple Linear Regression identified significant predictors using p-values and confidence intervals. Results showed that the mean values for hybridization ratio, mass fraction, fiber orientation, and low velocity impact were (2.50), (27.79%), (67.90°), and (3.82 J), respectively. It was found that the mass fraction had significant negative correlation with low velocity impact (r = -0.455; p = 0.000), as did the fiber orientation (r = -0.853; p = 0.000). The results for R = (0.994), R² = (0.989), F = (1607.390), and Durbin-Watson = (2.213) show that the regression model is highly predictive. Regression coefficients indicated negative effects from hybridization ratio (-0.357), mass fraction (-0.032), and fiber orientation (-0.017), all statistically significant (p = 0.000). Residual plots confirmed model validity. The TEM images of confirmation test sample 1 reveal fiber-matrix interfaces with particle sizes between 10.02–26.40 nm. Variations in scale (100 nm and 50 nm) show microstructural differences, suggesting strong adhesion, dispersion aggregation, and anisotropic behavior due to 90-degree fiber orientation within epoxy matrix. The study concludes that strategic optimization of input parameters significantly enhances the impact resistance of hybrid biocomposites.
Characterization of Curcumin as a Coating Material for Polymer-Free Stents in Terms of Morphology and Release Putri Akhmad Yani, Ameliyana Rizky Syamara; Herliansyah, Muhammad Kusumawan
Journal of Mechanical Engineering Science and Technology (JMEST) Vol 9, No 1 (2025)
Publisher : Universitas Negeri Malang

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.17977/um016v9i12025p074

Abstract

The use of bare metal stents over the long term often leads to the re-narrowing of blood vessels, prompting a shift to drug-eluting stents (DES). However, the use of polymers in DES has been known to trigger inflammation and thrombosis in the arteries. As an alternative, polymer-free drug-eluting stents (PF-DES) have emerged as a safer option. In this study, curcumin was selected as the primary coating material for PF-DES using the electrophoretic deposition method. The effects of varying curcumin concentrations (125 µg/ml, 250 µg/ml, and 500 µg/ml) were examined to understand their impact on deposition morphology, coating weight, chemical bonding characteristics, and curcumin release using scanning electron microscopy, ultraviolet-visible spectrophotometry, and Fourier transform infrared spectroscopy. The results showed that increasing the amount of curcumin resulted in a heavier and rougher coating, with deposition weights of 573.22 μg/cm², 1198 μg/cm², and 11954 μg/cm², after coated with curcumin concentrations of 125 µg/ml, 250 µg/ml, and 500 µg/ml, respectively. The curcumin release process was comprised of three phases: an initial burst, a slower release, and a second burst, which completed the release over more than 40 days. The efficacy of curcumin as a coating for PF-DES facilitates a controlled and steady release of the drug.
Finite Element Analysis of the Construction Strength of Semi-Submarine Glass-Bottom Catamaran Puteri, Berliana Ayarent; Putrananda, Musdika Bagas Satria; Hutagalung, Christian Imanuel; Bahatmaka, Aldias; Aryadi, Widya
Journal of Mechanical Engineering Science and Technology (JMEST) Vol 9, No 1 (2025)
Publisher : Universitas Negeri Malang

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.17977/um016v9i12025p243

Abstract

Indonesia's extraordinary marine tourism potential requires innovation in how to enjoy it. This study discusses the innovative design of a semi-submarine glass-bottom ship for the development of marine tourism in Indonesia, which allows tourists to enjoy the beauty of the underwater world safely and comfortably. This catamaran is designed with two hulls that provide high stability and optimal deck area for tourism needs. The study focuses on analyzing the ship's frame structure using the finite element analysis method, especially on using sandwich panels that combine wood and carbon fiber materials to achieve the optimal combination of structural strength, weight, and cost efficiency. Finite element analysis shows that sandwich panels with 100% carbon fiber composition provide the best mechanical performance with a maximum stress of 615.41 MPa. The analysis shows that adding carbon fiber plays a significant role in reinforcement and is a more effective stress distributor than homogeneous materials. Although the 100% carbon fiber formulation provides the highest safety factor, the study recommends a combination of 70% wood and 30% carbon fiber, or 60% wood and 40% carbon fiber for the construction of the ship's hull frame as a more optimal solution in terms of technical and economic aspects. This ship design innovation is expected to become a new tourist attraction that introduces the beauty of Indonesia's underwater world to domestic and foreign tourists while encouraging the development of a sustainable marine tourism industry.

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