Komponen mesin dapat diproduksi dengan variasi metode manufaktur seperti, penempaan, permesinan, pengecoran, atau metode pengelasan. Pemilihan metode manufaktur berdasarkan biaya produksi untuk setiap bagian pada komponen tertentu. Friction welding sebagai proses produksi masal merupakan metode manufaktur yang diminati untuk penggabungan dua material. Proses friction welding pada baja AISI 1045 dilakukan dengan menggesekkan kedua permukaan baja. Variasi waktu gesek yang digunakan yaitu 25, 35, 45, dan 55 detik kemudian dilakukan pengujian tarik, kekerasan, dan metalografi. Kekuatan tarik tertinggi yaitu 703,84 N/mm2 pada waktu gesek 45 detik. Kekerasan yang terbaik didapat pada waktu gesek 55 detik dengan nilai kekerasan 270 BHN. Struktur kristal dengan butiran halus akan menghambat dislokasi, sehingga mendapatkan sifat mekanik baja yang baik.
Wind energy has been developed and used as a source of electrical energy by converting wind energy into electrical energy using a generator. There are some wind turbine parameters that important for wind turbines design and model, includes the size of the rotor radius, airfoil selection, chord length, and pitch angle. The study aims to characterize the performance of a horizontal axis wind turbine using computational methods. The methods used a design and simulation of NACA 4412 and NACA 4712 airfoil using QBlade software using wind conditions in the region of Pancer, Jember. Results show that the maximum Cl value of NACA 4712 is higher than in NACA 4412. NACA 4712 has a maximum Cl value = 1.696 at α = 14 o while NACA 4412 airfoil has a maximum value of Cl = 1.628 at α = 15 o. NACA 4712 has the maximum value of Cl/Cd = 153 at α = 2 o , while the NACA 4412 has a maximum value of Cl/Cd = 133.5 at α = 5.5 o. The maximum value of Cl/Cd 4712 is higher than the NACA 4412. At 7.66 m/s of wind speed with 10% turbulence conditions, wind turbines with NACA 4712 airfoil have Cp turbine performance parameters of 0.49929 and obtain a power of 1.15 kW, while wind turbines with NACA 4412 have Cp turbine performance parameters of 0.395365 and obtained power of 0.889 kW at the same wind speed.
3D printing technology or additive manufacturing is manufacturing by adding materials to objects until it is shaped as expected. This technique is easy and cheap for printing polymer-based materials in the form of filament. Recently, some metal-containing filament has been introduced in the market, one of which is eSteel composed of 45% wt. steel and 55% wt. PLA. Due to its premature introduction, it is a minimal published paper discussing its mechanical properties and dimensional accuracy. This research aims to analyze the dimensional accuracy of 3D printed products of the fused deposition modeling (FDM) technique using eSteel filament. Taguchi method was used to design the experiments with orthogonal array L4 (23). There were three control parameters with two levels each, namely extruder temperature (220°C, 225°C), layer height (0.3 mm, 0.4 mm), and raster angle (0°/90°, 45°/45°). These parameters were selected based on initial trials. The specimens are in the form of an ASTM D790 flexural test with five replications in each combination. HE3D K200 3D printing machine was used for printing the filament. Analysis of variance indicated that raster angle has the most influence on dimensional accuracy by 32.09%, followed by extruder temperature with a contribution of 31.72% and layer height by 25.53%. The combination of control parameters to produce optimal dimensional accuracy was obtained when combining parameters: extruder temperature of 220°C, layer height of 0.3 mm, and raster angle of 0°/90°.
Penggunaan plastik akan semakin meningkat seiring dengan bertambahnya jumlah populasi penduduk dan meningkatnya perkembangan teknologi. Meningkatnya sampah plastik menjadi masalah besar bagi kehidupan dan ekosistem, Karena plastik sulit terurai di dalam tanah dan membutuhkan waktu yang lama untuk dapat terurai. Dengan adanya permasalahan tentang banyaknya sampah plastik yang sulit di uraikan maka dapat dilakukan dengan metode pirolisis, metode pirolisis adalah proses pemanasan sampah plastik dengan menggunakan sedikit oksigen atau tanpa oksigen di dalamnya. Untuk memperbaiki minyak hasil pirolisis maka ditambahkan katalis sebagai katalisator sehingga memperoleh hasil minyak pirolisis lebih baik. Tujuan penelitian ini adalah untuk mengetahui perbedaan minyak PET (polyethylene terephthalate) dan PP (polypropylene), untuk membandingkan hasil pirolisis dari penggunaan katalis dan tidak menggunakan katalis terhadap viskositas minyak yang dihasilkan, serta pengaruh waktu pemanasan terhadap hasil volume minyak pirolisis. Dari penelitian yang dilakukan didapatkan hasil minyak terbanyak dengan bahan plastik PP dengan katalis 33 ml atau 8,46 %, PET katalis 23 ml atau 8,943 % dan minyak PP tanpa katalis 76 ml atau 19,26 %, PET tanpa katalis 65 ml atau 17,23%. The use of plastic will increase along with the increasing population and increasing technological development. Increased plastic waste is a big problem for life and ecosystems, because plastic is difficult to decompose in the soil and requires a long time to be decomposed. With the problem of the amount of plastic waste that is difficult to describe, it can be done with the pyrolysis method, the pyrolysis method is the process of heating plastic waste using little or no oxygen in it. To improve the pyrolysis oil, the catalyst is added as a catalyst to obtain better pyrolysis oil results. The purpose of this study was to determine the differences in PET (polyethylene terephthalate) and PP (polypropylene) oils, to compare the results of pyrolysis from the use of catalysts and not use catalysts to the viscosity of the oil produced, as well as the effect of heating time on the results of the pyrolysis oil volume. The results of the research showed that most PP plastic catalyst oils were 33 ml or 8.46%, catalyst PET 23 ml or 8.943% and PP oil without catalyst 76 ml or 19.26%, PET without catalyst 65 ml or 17.23%.
Neutronic analysis on the Molten Salt Reactor FUJI-12 using the fissile material 235U in LiF-BeF2-UF4 has been carried out. The problem faced in the use of thorium-based fuel is that the amount of 233U is small and not available in nature. 233U was produced through the 232Th breeding at a cost of $46 million/kg. That is a very high price when compared to 235U enrichment, which is only $100/kg. The MSR FUJI-12 used in this study is a generation IV reactor with a mixture of liquid salt fuel LiF-BeF2-ThF4-UF4 and thorium-based fuel (232Th+233U). In this study, neutronic analysis was carried out by replacing thorium-based fuel with uranium-based fuel (235U+238U). Neutronic analysis was performed using the OpenMC 0.13.0 code, which is a Monte Carlo simulation-based neutron analysis code. The nuclear data library used for neutronic calculations is ENDF B-VII/1. The fuel is used in a LiF-BeF2-UF4 molten salt mixture with three eutectic compositions: fuel 1, fuel 2, and fuel 3. Each fuel composition is optimized by enriching 235U in UF4 by 3 % to 8 %. The optimization results show the stability of the reactor criticality value, which is the main parameter so that the reactor can operate for the specified time. The optimization results show that fuel 1 cannot reach its optimal state in each variation of 235U enrichment. Fuel 2 and fuel 3 can reach optimal conditions at a minimum enrichment of 8 % and 7 % 235U. The results of the analysis of the distribution of the neutron flux in the reactor core show the distribution of nuclear reactions that occur in the core. The distribution of flux values in fuel 1 shows that the fission chain reaction is not running perfectly. Fuel 2 and fuel 3 are more stable by maintaining maximum flux at the center of the reactor core.
The engine movement mechanism is a system composed of machine elements that contact or rub against each other between these surfaces. Surfaces that rub against each other will cause a friction force that causes wear on the surface, so it requires energy to fight the friction force. Lubricants are needed to reduce friction and reduce wear rates, where lubricants are generally made of mineral materials. Lubricants made from synthetic materials are non-renewable and cause environmental problems. The development of biolubricants as lubricating materials based on animal fats or vegetable oils is continuously being carried out. This study aims to observe the potential of biolubricants based on reviews from various previous research journals. The use of additives in biolubricants is also studied whether the addition of these additives can improve the characteristics of biolubricants. This study shows that the addition of certain additives to biolubricants can improve the characteristics of biolubricants.
Seaplanes are aircraft that can take off and landing on water. A seaplane’s requirement is its need to take off and landing on watery conditions which is equipped with a pontoon. Pontoon of a seaplane needs to be evaluated in terms of aerodynamics characteristics when a seaplane flies. The purpose of this study is to determine the correlation of various geometric combinations of deadrise angle, step height, and constant cross-section length with the values of coefficient of drag (CD), coefficient of lift (CL) and coefficient of moment (CM). The methodology was carried out by simulating Computational Fluid Dynamics (CFD) using OpenFOAM software. The results of this study could be concluded that deadrise angle affected coefficient of drag (CD), coefficient of lift (CL) and coefficient of moment (CM) with each value of 0.0055, 0.0044, -0.0036, while step height didn’t influence significantly on coefficient of drag (CD) and didn’t affect coefficient of lift (CL) and coefficient of moment (CM). Constant cross-section length didn’t affect significantly on coefficient of drag (CD) and coefficient of lift (CL) but increasing constant cross-section length increased coefficient of moment (CM) with a value of -0.0039.
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