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INDONESIA
Rotasi
Published by Universitas Diponegoro
ISSN : 1411027x     EISSN : 24069620     DOI : -
Core Subject : Engineering,
Mechanical Engineering
Arjuna Subject : -
Articles 12 Documents
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Search results for , issue "Vol 26, No 4 (2024): VOLUME 26, NOMOR 4, OKTOBER 2024" : 12 Documents clear
Experimental Study of the Use of Rubber Seeds as Biodiesel Feedstocks; Production Optimization, Characterization and Performance Testing Tambunan, Bisrul Hapis
ROTASI Vol 26, No 4 (2024): VOLUME 26, NOMOR 4, OKTOBER 2024
Publisher : Departemen Teknik Mesin, Fakultas Teknik, Universitas Diponegoro

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.14710/rotasi.26.4.60-70

Abstract

This study's objective was to create and characterize biodiesel from rubber seeds. Rubber seeds collected from smallholder plantations in the northern Sumatra region of Indonesia are peeled to separate the shell from the kernel. The rubber seed kernels are boiled for 4 hours to boiled to release the sap. The boiled kernels are drained and dried in the sun for two days in sunny weather. Furthermore kernels boiled and dried are pressed with a screw press machine, and RSO (rubber seed oil) is obtained. This RSO is produced into RSB (Rubber Seed Biodiesel) using a double jacket reactor through degumming, esterification, and trans-esterification stages. Biodiesel production is carried out with variations in the ratio of catalysts, temperature, and reaction time. For each of these variables, the yield of biodiesel produced is calculated. Then the biodiesel produced was characterized through psycho-chemical property testing, including calorific value, cetane number, oxidation stability, density, viscosity, acid content, pour point, and flash point. Furthermore, the biodiesel was tested on a diesel engine at several engine speeds to observe its performance and emissions. In biodiesel production, the maximum yield is the catalyst/crude oil ratio = 0.75, the oil/methanol molar ratio = 1:1.25, the reaction temperature is 60 oC and the reaction time is 100 minutes, but the yield increase from 90 minutes to 100 minutes is not significant. RSB meets ASTM biodiesel standards except for oxidation stability, which is 1.2 hours instead of 3 hours. RSB engine performance and exhaust emissions are comparable to biodiesel in general.
Development of Footprint Analysis Software Using the Cavanagh Arch Index Method Based on a MATLAB GUI Umardani, Yusuf; Wibowo, Dwi Basuki; Suprihanto, Agus; Basyith, Mohammad Rizqi Abdul
ROTASI Vol 26, No 4 (2024): VOLUME 26, NOMOR 4, OKTOBER 2024
Publisher : Departemen Teknik Mesin, Fakultas Teknik, Universitas Diponegoro

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.14710/rotasi.26.4.13-26

Abstract

The human foot plays a crucial role in supporting body weight and maintaining mobility. It is divided into three main sections: the heel, the arch (middle section), and the forefoot. Based on arch structure, feet are categorized into three types: normal, flat foot, and high arch. Flat feet can negatively affect foot health, making the identification of foot types critical for preventive care. In Indonesia, identification often relies on the wet foot test, which has limitations in accuracy. Therefore, a more effective identification system is needed. Previous studies developed software to identify foot types through digital images, but these lacked advanced features and image quality options. This research aims to develop new software that can operate a scanner, process images directly, and offer flexible editing options for improved image quality. The software was developed using MATLAB r2021B GUI, employing image acquisition and processing toolboxes. The results demonstrate high accuracy, with processing differences of 0.73% for length, 1.22% for width, 1.06% for shoe size, 1.34% for FAC, and 2.49% for the arch index compared to previous software versions.
Analisis Pengaruh Variasi Komposisi Material Komposit Berbahan Limbah Serat Daun Nanas pada Bilah Turbin Arus Laut Fauzan, Muhamamd; Rizki, Alifia Laila; Pratiwi, Dwi Berninda; Kartika, Niken Yuniar; Firmansyah, Davin Maulana Isnan; Junianto, Sony
ROTASI Vol 26, No 4 (2024): VOLUME 26, NOMOR 4, OKTOBER 2024
Publisher : Departemen Teknik Mesin, Fakultas Teknik, Universitas Diponegoro

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.14710/rotasi.26.4.71-79

Abstract

Indonesia memiliki potensi besar untuk mengembangkan Pembangkit Listrik Tenaga Arus Laut (PLTAL) dengan energi kinetik arus laut yang dapat diubah menjadi listrik. Namun, turbin di lingkungan air laut rentan terhadap korosi yang dapat menurunkan kualitas dan efektivitas turbin arus laut. Untuk mencegah korosi, material komposit dipilih karena sifat mekaniknya yang lebih baik dan kemampuannya dalam menunda korosi. Penelitian ini berfokus pada pemanfaatan serat daun nanas (Pineapple Leaf Fiber, PALF) sebagai bahan komposit untuk bilah turbin arus laut. Serat daun nanas dipilih karena melimpah, ekonomis, terbarukan, dan memiliki kekuatan tarik tinggi. Penelitian ini bertujuan untuk menganalisis komposisi serat daun nanas sebagai bahan komposit, mengukur kekuatan bilah turbin arus laut dengan material komposit, serta menganalisis laju korosi bilah turbin yang berada di lingkungan arus laut. Metode penelitian yang digunakan adalah dengan uji tarik dan uji laju korosi pada beberapa sampel spesimen dengan lima variasi komposisi serat daun nanas dan resin. Hasil pengujian didapatkan nilai modulus young dan corrosion rate yang digunakan untuk menganalisis variasi yang paling efektif sebagai pembuatan bilah turbin arus laut. Kemudian dari hasil tersebut digunakan untuk membuat bilah turbin arus laut yang sesuai dengan variasi yang didapatkan. Hasil penelitian dimungkinkan untuk mengurangi biaya operasional turbin, memanfaatkan limbah alam yang terbuang, dan mengembangkan inovasi teknologi energi terbarukan dengan material komposit yang ramah lingkungan dan tahan korosi.
Analisis Parameter Fisik Filamen Biokomposit PLA PCL HA Hasil Proses Ekstrusi Hidayat, Wahyu; Bayuseno, Athanasius Priharyoto; Ismail, Rifky; Fitriyana, Deni Fajar; Cionita, Tezara; Prawibowo, Hartanto
ROTASI Vol 26, No 4 (2024): VOLUME 26, NOMOR 4, OKTOBER 2024
Publisher : Departemen Teknik Mesin, Fakultas Teknik, Universitas Diponegoro

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.14710/rotasi.26.4.27-32

Abstract

Penelitian ini berfokus pada tantangan implan logam yang memerlukan operasi kedua, serta risiko infeksi, peradangan, dan korosi yang mungkin terjadi di dalam tubuh. Untuk mengatasi masalah tersebut, penelitian ini mengembangkan material biokomposit yang terdiri dari PCL (Polycaprolactone), PLA (Polylactic Acid), dan Hidroksiapatit (HA), yang dapat terbiodegradasi secara alami di dalam tubuh. Sistem yang diusulkan mampu meningkatkan kontrol pengguna secara signifikan, serta menjadi fondasi untuk sistem kontrol lengkap dalam pembuatan filamen biodegradable. Hal ini dilakukan dengan mengatur parameter motor untuk mencapai diameter filamen yang konsisten dengan deviasi minimal serta mengontrol laju ekstrusi pada printer guna memperbaiki ketidakstabilan filamen.Penelitian ini juga akan membandingkan filamen yang dihasilkan dengan filamen komersial PLA merek SUNLU. Perbandingan tersebut meliputi evaluasi parameter fisik seperti ukuran diameter hasil ekstrusi, densitas filamen setelah penambahan PCL dan HA, serta apakah penampang filamen membentuk lingkaran sempurna. Hasil dari penelitian ini akan memberikan wawasan lebih dalam tentang kualitas fisik filamen yang dihasilkan.
Design of A Green Hydrogen System Powered by Solar Power Plants in Lombok Parman, Parman
ROTASI Vol 26, No 4 (2024): VOLUME 26, NOMOR 4, OKTOBER 2024
Publisher : Departemen Teknik Mesin, Fakultas Teknik, Universitas Diponegoro

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.14710/rotasi.26.4.80-90

Abstract

Hydrogen is a carbon-free energy source with significant potential as a sustainable energy carrier for the future. Green hydrogen production through renewable energy sources, such as Solar Power Plants (PLTS), offers high potential for decarbonizing various sectors and addressing climate change challenges. This research aims to design a hydrogen production system integrated with a PLTS system in Lombok. Using MATLAB Simulink, a model is utilized to simulate the potential for green hydrogen production using an off-grid PLTS. The study includes an analysis of the PLTS system design, an electrolyzer model, and an energy storage system. Solar radiation data from 2023 is used as the basis for the simulation. The simulation results show that a PLTS with a capacity of 2.33 MWp and a Proton Exchange Membrane (PEM) electrolyzer system with a power of 2 MW can produce 121,391 kg of hydrogen per year.
PROSES MANUFAKTUR LENGAN PROSTESIS BERBASIS PENGGERAK KABEL HARNESS MENGGUNAKAN TEKNOLOGI 3D PRINTING Hudaya, Akhmad Zidni; Winarso, Rochmad; Rohman, Nafaqotur
ROTASI Vol 26, No 4 (2024): VOLUME 26, NOMOR 4, OKTOBER 2024
Publisher : Departemen Teknik Mesin, Fakultas Teknik, Universitas Diponegoro

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.14710/rotasi.26.4.33-46

Abstract

enelitian ini menyoroti tantangan dan solusi dalam pengembangan prostesis tangan yang fungsional, terutama bagi individu dengan amputasi transradial, yang mengalami hambatan signifikan dalam aktivitas sehari-hari. WHO menyatakan bahwa 10% dari populasi global memiliki disabilitas, dengan 80% di antaranya berada di negara berpenghasilan rendah. Amputasi lengan dan tangan menyebabkan gangguan fungsional yang besar dan menurunkan kualitas hidup. Prostesis modern, meskipun menawarkan manfaat kosmetik dan mekanis, seringkali mahal dan sulit diakses di negara berkembang. Penelitian ini mengeksplorasi penggunaan teknologi pencetakan 3D dan desain berbantu komputer (CAD) untuk menciptakan prostesis yang lebih terjangkau dan fungsional. Dalam penelitian ini, proses desain menggunakan Autodesk Inventor 2020 dan Ultimaker Cura 5.7.1 untuk slicing (lapisan tipis) dan pencetakan 3D prostesis tangan. Hasil menunjukkan penyimpangan waktu dan dimensi dalam pencetakan yang memerlukan peningkatan proses untuk mencapai akurasi yang lebih baik. Uji coba dengan satu pasien menunjukkan fungsi dasar prostesis yang memadai, tetapi perlu penyesuaian lebih lanjut untuk meningkatkan kenyamanan dan efisiensi penggunaan. Penelitian ini menekankan pentingnya inovasi dan pengoptimalan dalam desain dan produksi prostesis untuk memenuhi kebutuhan pengguna dan meningkatkan kualitas hidup mereka
Simulation Study of Pin-Type Heatsinks on Convection Heat Transfer Characteristics in Electronic Devices Chaniago, Noverto Zhorif; Alfian, Devia Gahana Cindi; Syaukani, Muhammad; Pujiyulianto, Eko; Nurullah, Fajar Perdana; Silitonga, Dicky Januarizky
ROTASI Vol 26, No 4 (2024): VOLUME 26, NOMOR 4, OKTOBER 2024
Publisher : Departemen Teknik Mesin, Fakultas Teknik, Universitas Diponegoro

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.14710/rotasi.26.4.47-53

Abstract

Electronic components are components that require an optimal design in order to provide good heat release performance. The heat sink component is a relevant solution to help cool an electronic component by flowing heat energy into the environment either naturally or forcibly with the help of a fan. The purpose of this study is to determine the effect of material type on heat sink temperature distribution, determine the phenomenon of velocity boundary layer and thermal boundary layer that occurs in each heat sink variation, determine the effect of design shape and pin arrangement on pressure drop, determine the best design according to the final results of the study. This research uses 6 variations of design shape, 2 variations of arrangement (inline and staggered), and 3 types of materials (Aluminum, Copper, and Iron). The method used in this research is a simulation method with three stages of process, namely, pre processing, processing, and post processing. The results showed that copper material is the best in conducting heat with a temperature drop of 98.5% from the base temperature. The inline arrangement obtained a lower pressure drop than the staggered arrangement and the best design was obtained by fillet square perforation with an inline arrangement.
Material characteristics and failure prediction of SA 213 Superheater Boiler tube in power plant with 315 MW capacity Nugraha, Ariyana Dwiputra; Harianto, Harianto; Suprihanto, Agus; Sulardjaka, Sulardjaka
ROTASI Vol 26, No 4 (2024): VOLUME 26, NOMOR 4, OKTOBER 2024
Publisher : Departemen Teknik Mesin, Fakultas Teknik, Universitas Diponegoro

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.14710/rotasi.26.4.1-5

Abstract

This study was conducted at the Rembang Semarang Unit 2 power plant in Indonesia, with a capacity of 315 MW. The plant has been in operation since 2011, totaling about 13 years or over 100,000 equivalent operating hours (EOH). High-temperature operations can damage tube materials due to temperature, corrosive environment, pressure, and stress. At the end of 2022, a condenser leak at the plant necessitated an assessment of the boiler tube material. This study focuses on evaluating the SA 213 T91 (chromium (Cr) and molybdenum (Mo) alloy steel) superheater tube, a known for its excellent high-temperature mechanical and thermal properties and corrosion resistance. The research aims to assess potential failures in the boiler tube and guide future operational and maintenance plans. The analysis includes destructive testing, SEM, EDX metallography, and creep rupture testing. Results show corrosion and hard scale deposition inside the tube. Its is shown that creep strength decreases significantly at high temperatures, leading to faster material rupture.
Design and Fabrication of Jig and Fixture for Milling Operations in the Manufacturing Sector Indrawan, Rizal; Purnomo, Dhika Aditya; Bisono, Fipka; Karuniawan, Bayu Wiro; Fajardini, Ridhani Anita
ROTASI Vol 26, No 4 (2024): VOLUME 26, NOMOR 4, OKTOBER 2024
Publisher : Departemen Teknik Mesin, Fakultas Teknik, Universitas Diponegoro

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.14710/rotasi.26.4.54-59

Abstract

Fixtures and jigs are work-holding devices used to position and support workpieces. Fixtures and jigs are important tools in production because their use determines the performance of the entire production process of a product. There are still situations in the manufacturing sector where products manufactured could be more precise. Work-holding devices that facilitate the machining process must be developed to ensure that the final products satisfy the required criteria. This study aimed to design, manufacture, and evaluate fixtures and jigs and then assess how well they worked with test specimens in rectangular shapes. The jigs and fixtures are planned based on a vacuum table that is adjusted to the machining position on the side of the material. The intention of employing a vacuum system is to simplify the process of setting up the workpiece. Fusion360 Design Software was utilized to design fixtures and jig models. Since aluminum is easy to form and has high wear resistance, it was chosen as the workpiece material. CNC machine was employed in the manufacturing process. Testing of jig and fixture tools is carried out on the side of the test specimen. According to the study's findings, jigs and fixtures accelerate the milling process on the material side. When jigs and fixtures are used, the milling process proceeds 17.47 minutes. Using this jig and fixture makes it possible to shorten the operating time, making the milling process run more quickly. Furthermore, the final product has remarkable dimensional accuracy.
Analisis Computational Fluid Dynamic (CFD) Pengaruh Overlap Ratio dan Jarak Bilah Berlapis pada Kinerja Turbin Angin Savonius Bilah Berlapis David, Jerico; Fahrudin, Fahrudin; Rhakasywi, Damora
ROTASI Vol 26, No 4 (2024): VOLUME 26, NOMOR 4, OKTOBER 2024
Publisher : Departemen Teknik Mesin, Fakultas Teknik, Universitas Diponegoro

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.14710/rotasi.26.4.6-12

Abstract

Abstract  The demand for energy is increasing, therefore researchers are utilizing alternative energy sources such as wind energy. Savonius is a type of vertical axis wind turbine (VAWT) that is suitable for use in low wind speed conditions, making it capable of operating in urban areas. Researchers are conducting extensive studies to improve the performance of Savonius wind turbines. The Savonius wind turbine used is a Savonius wind turbine with added layered blades. This research was conducted using the computational fluid dynamics (CFD) simulation method with an existing layered Savonius wind turbine model and varied the overlap ratio and the distance between the layered blades to determine the impact of these variations on efficiency improvement using Ansys Fluent 2022 R2 software. The variations in this study included an overlap ratio of 10% with a blade distance of 33 mm and an overlap ratio of 15% with blade distances of 22 mm and 33 mm at a wind speed of 6.46 m/s. The results showed that the layered Savonius wind turbine from previous research with a configuration of a 10% overlap ratio and a blade distance of 22 mm had the best performance with a power coefficient (Cp) of 0.173 and a torque coefficient (Ct) of 0.46. The results of this study provide an understanding of the impact of increasing the value of the layered blade distance and the overlap ratio on the performance of the Savonius wind turbine, which, if not appropriate, can reduce its efficiency. Keywords: wind energy, Savonius wind turbine, layered blades, overlap ratio, distance between layered blades

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