1,720,963 research outputs found
REDUKSI SUARA LENGKINGAN PADA STRUKTUR DINAMIK DENGAN BEBAN GESEK MELALUI MODIFIKASI STRUKTUR
No full textSuara lengkingan (squeal noise) merupakan salah satu sumber polusi suara yang
paling banyak ditemukan pada proses pengereman dan kendaraan rel yang
bergerak pada belokan atau tikungan. Salah satu ciri khas dari suara lengkingan
ini adalah frekuensi yang didominasi oleh hannya satu atau dua frekuensi dengan
intensitas yang sangat tinggi pada rentang frekuensi 1 - 20 kHz. Tulisan ini
difokuskan pada modifikasi struktur mekanik dengan penambahan massa untuk
mengurangi suara lengkingan akibat beban gesek.
Pada penelitian ini ada dua struktur yang akan diuji yaitu struktur rangka
berbentuk L dan struktur cakram. Pada struktur L ada dua metode penambahan
massa yaitu penambahan massa ditekukan dan penambahan massa diujung
struktur L yang bebas. Pada struktur berbentuk cakram, massa tambahan diletakan
ditepi bagian atas cakram yang diposisikan menjadi 3 bagian penempatan yaitu
2 titik, 4 titik dan 8 titik. Perbandingan dari masing-masing titik dilakukan untuk
melihat pengaruh dari posisi massa tambahan pada struktur untuk mereduksi suara
lengkingan akibat gesekan.
Dari hasil penelitian diperoleh untuk struktur berbentuk L, massa tambahan
21 gram di ujung bebas struktur L mampu meredam suara lengkingan sebesar
2239 Hz pada tekanan suara 65.05 dB. Untuk struktur berbentuk cakram,
penambahan massa 8 titik ditepi atas struktur cakram sebesar 50 gram dapat
menurunkan suara lengkingan hingga frekuensi 2114 Hz dengan tekanan suara
37.5 dB. Melalui penelitian ini diperoleh bahwa penambahan massa pada struktur
mekanik yang bergesekan yang menimbulkan suara lengkingan dapat diterapkan
untuk menggeser atau mereduksi daerah tak stabil modus terkopel dengan cara
menghilangkan daerah tak stabil dari kondisi kerja.
Kata Kunci : Suara lengkingan, modus terkopel, penambahan mass
DESIGN AND BUILD A COCONUT HUSK CHOPPER MACHINE USING AN 8 HP GASOLINE ENGINE
Full text linkThe coconut frond cutter or coconut frond shredder is a device used to transform coconut fronds into small pieces, even turning them into a finely textured material. This study examines the design and development of a coconut-chopping machine that uses an 8 HP combustion motor. Structural analysis was performed on the machine frame by considering the maximum and minimum Von Mises Stresses. The analysis results show that the maximum Von Mises Stress in the frame is 1.670e+06 N/mm², while the minimum stress is 2.338e+04 N/mm². The displacement of the frame was observed at 2.642e-02 mm to 1.000e-30 mm. The safety factor of the frame was found to be 1.366e+02, indicating an adequate level of safety. Next, this study analyzed the shredding capacity of the machine. The analysis showed that the largest shredding capacity was 3619.30 kg/hour, which occurred at a high rotation of young fronds, producing fine shreds. Meanwhile, the smallest shredding capacity of 612.66 kg/hour occurs at low rotation of old fronds and produces coarse shreds. These results provide essential insights into using coconut shredding machines based on the rotation level and the processed material. This research contributes to the development of efficient and effective coconut processing technology
Optimasi Waktu dan Kapasitas Produksi Desain Pion Menggunakan Mesin CNC Bubut Melalui Simulasi Autodesk Fusion
Full text linkModern manufacturing industries face challenges in improving efficiency and product quality. In this study, a pawn was designed using Autodesk Fusion 360, followed by a turning process simulation to optimize machining parameters such as cutting speed, feed rate, and depth of cut. The simulation was conducted to identify potential issues such as tool wear and dimensional inaccuracies before the actual production process. The results showed that implementing simulations effectively minimized production time, improved dimensional accuracy, and reduced tool wear. The applied optimization parameters successfully shortened the production cycle and produced defect-free products that met the required specifications. This study concludes that simulation and optimization in CNC turning machines not only enhance production efficiency and capacity but also ensure consistent product quality, making them highly relevant for modern manufacturing industries.Kata kunci: Simulation, Optimization, CNC Turnin
Rancang Bangun Mesin Pencetak Bakso
Full text linkThis research to design a smaller and easy to operate meatball maker machine. This design will simplify, speed up and minimize the energy expended in the meatball maker machine. Simulation of frame strength using Solidwork 2018. The simulation value of von Mises stress on the frame is with a maximum stress of 10,550,430.00 N/m2 and a minimum of 90,629 N/m2 with a yield strength of 250,000,000.00 N/m2. Displacement in the simulation of displacement is with a maximum value of 0.154 mm and a minimum of 0.000 mm. The value of the safety factor from the simulation results is 24. Static simulation results of the strength of the meatball printing machine frame using ASTM A36 Steel L 30 mm x 30 mm 3 mm thick with a load of 25 kg, the frame is able to withstand engine performance during operation
Reduksi Suara Lengkingan pada Struktur Cakram dengan Beban Gesek melalui Penambahan Massa
No full textSuara lengkingan (squeal noise) sering terjadi jika salah satu permukaan kontak logambergesekan dengan permukaan logam lainnya padakondisi tertentu. Dalam banyakpengamatan, spektrum frekuensi yang dihasilkan didominasi oleh sejumlah puncak yangsangat tajam biasanya dalam rentang frekuensi 1-20 kHz, sering berupa bentuk frekuensitunggal. Tulisan ini difokuskan pada modifikasi struktur untuk mengurangi suara lengkinganyaitu dengan menambahkan massa pada struktur bebentuk cakram sebagai pemodelan daribentuk sederhana dari roda kereta api. Beberapa massa ditambahkan pada struktur cakramuntuk mencegah getaran yang tidak stabil akibat gesekan dan untuk untuk mengurangi suaralengkingan. Dalam penelitian sebelumnya ditemukan bahwa penambahan massa untukstruktur dengan gesekan yang menyebabkan suara lengkingan dapat diterapkan untukmenggeser atau mengurangi wilayah yang tidak stabil dari modus terkopel. dengan caramenghilangkan daerah tak stabil dari kondisi kerja. Pada penelitian ini, penambahan dua,empat dan delapan massa tambahan dengan berbagai ukuran ditambahkan di tepi cakram,dimana amplitudo getarannya lebih tinggi dibandingkan diposisi lainnya. Sehingga didapatkanbahwa dengan menambahkan delapan massa tambahan ditepi cakram suara lengkingan dapatdihilangkan, terutama dengan penambahan massa 50 gram dapat menghilangkan suaralengkingan dan dapat menggeser frekuensi pribadi menjadi 2114 Hz.Kata Kunci : suara lengkingan, modus terkopel, peredam dinamik,penambahan massa
Squeal noise often occurs when a contact surfaces of metal rubbing against another metalsurface under certain conditions. In many observations, the frequency spectrum is dominatedby a number of very sharp peaks typically in the frequency range 1-20 kHz, often in singlefrequency form. This paper is focused on structural modifications to reduce the squeal noise byadding a mass in a simple thin disc as a simple model of train wheel where squeal noise isfrequently found when the train moves at curve track. Some masses are added to the disc toprevent unstable vibration caused friction and reduce the squeal noise. In previous study it isfound that the addition of mass to the structure with friction that causes the squeal noise canbe applied to shift or reduce unstable region of coupled mode. It works by removing theunstable region of the operating conditions. In this case two, four and eight lump masses withvarious mass is added to the edge of the disc where the vibration amplitude relatively higherthan other position. It is found that by adding eight-lump masses to thin disc the squeal noisecan be eliminated, especially by the addition 50 grams of the mass can eliminate the squealnoise, and shift the natural frequency to 2114 Hz.Keywords: squeal noise, coupled mode, additional mas
Analisa Kebutuhan Beban Pendingin Untuk Aula Kampus III UM Sumatera Barat
Full text linkThe comfort factor of a room is determined according to the location, characteristics and activities in the room. In order for the room to feel comfortable, a tool is needed to cool the room. The hall of Campus III UM West Sumatra as a place for academic activities measuring 28.3 m long, 8.3 m wide, 3.2 m high with a capacity of 130 people, requires air conditioning according to the needs of the room. This study aims to determine the need for air conditioning cooling load for the hall space. The research carried out literature review and observation, calculating temperature, temperature, hall size, and others. The result of the research is that the cooling load is 25.44 kW, so 3 units of split PK type AC are neede
Analisis Kekuatan Rangka Mesin Perontok Padi Menggunakan Solidworks 2019
Full text linkIndonesia is one of the largest rice producers in the world. technological developments created a rice threshing machine to facilitate the work of farmers. In the manufacture of the engine frame, of course, must be calculated accurately. Here the SolidWorks 2019 application is used to make it easier to analyze the strength of the rice threshing machine frame. In the simulation of the strength of the frame using SolidWorks 2019, the type of material used is ASTM A36 Steel, and loading is carried out on the frame with a load of 1 of 50 kg and a load of 2 of 30 kg. The simulation results get the largest von misses stress value at load 2 of 79,183,792,000 N /m2 with a displacement of 0.657 mm. The safety factor values obtained from the simulation results are 3 and 2,635. Based on Dobrovolsky in the book "machine element" the safety factor range for dynamic loads is 2.0 - 3.0, then the strength of the frame of the rice thresher machine is able to support the performance of the machine during use
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
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