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Abstrak :
Gasifikasi merupakan proses untuk merubah biomassa menjadi syngas yaitu gas mampu bakar yang dapat digunakan untuk energi listrik. Indonesia memiliki potensi mencapai 35.6 GW dengan padi menjadi penyumbang terbesar 19.41 GW. Gasifier purwarupa 2 P2 ini merupakan hasil improvisasi dari gasifier purwarupa 1 P1 milik laboratorium gasifikasi biomassa Universitas Indonesia. Gasifier P2 dibuat dengan menutupi celah udara masuk melalui sistem rotary feeder dan menjaga kestabilan penurunan zona dengan sistem vibrating grate. Gasifier P2 memiliki diameter 0.4m dan diameter 0.25m dan memiliki output sebesar 50kW. Melalui proses analisis perhitungan empiris didapatkan bahwa jangkauan operasional reaktor harus memiliki feed rate yang berada diatas 12.6 kg/hr dan sesuai dengan referensi jurnal maka berada didalam jangkauan 18-28 kg/hr maka dengan begitu nilai CGE gasifier berada di rentang 40-65%. Parameter Operasional ini dibuat untuk diintegrasikan dengan sistem komputer dengan harapan proses optimasisasi secara operasional dapat meningkatkan mutu syngas. Metode perhitungan dikomparasi melalui perbandingan dengan jurnal dan dengan perhitungan penyetaraan energi dan massa. Analisis juga dilakukan terhadap sistem feeding dan vibrating grate untuk mengetahui potensi improvisasi yang dapat dilakukan. Sistem screwfeeder memiliki sudut inklinasi 60 yang menyulitkan transfer massa dan menciptakan potensi kegagalan sehingga sudut ini dapat dibuat lebih landai, perubahan kemiringan menjadi 25 dapat menghemat daya sampai 50%. Vibrating grate yang digunakan adalah AISI 304. Material tersebut dapat mengalami korosi batas butir yang mampu mengurangi kekuatan grate, namun secara umum beban kerja dari grate masih berada kapasitas operasional yang aman. List improvisasi dibuat sebagai rangkuman dan panduan evaluasi dan improvisasi Gasifier P2.

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Gasification is a process what convert biomasses into syngas that can be used as fuel or converted into electricity. Indonesias biomass potential is around 35.6 GW with rice husk being the largest reserves with around 19.41 GW. Gasifier Prototype 2 P2 was made as the result of improvisation of the Prototype 1 gasifier P1 created by biomass gasification laboratorys research team from University of Indonesia. The main improvements from P2 are sealing air gap that exist at the feeding system of P1 which can lead to leakage and syngas loss and the implement of the new char removal system, vibrating grate that can discards waste without ruining the working zone above it. Gasifier P2 has dimension of 0.4m height and 0.25m diameter and it is designed to have 50kW output. Through the analysis process of designing a downdraft gasifier, to obtain the output needed, P2 gasifier needs to have feed rate of minimum 12.6 kg/hr. Taking journals as reference the feed rate needed for practical use of gasifier is around 18-28 kg/ hr which has CGE value within the range of 40-65%. These operational parameters are made to be integrated with computer system in the hope that optimization process in operational parameter can improve the quality of syngas produced by the gasifier. The calculation method is then compared through calculations from other journals and with the parameter obtained by energy and mass balance calculation from experiment carried in P1 reactor. Analysis was also carried out for the feeding and char removal system. The screw feeder used in feeding system has an inclination angle of 60 which lessen the mass transfer rate while also consuming more power. Changing the slope to 25 can dramatically improves transfer rate and saves power up to 50%. Vibrating Grate used in char removal system used AISI 304 as its material. Such material that can be exposed to intergranular corrosion IGC which can lower the AISI 403s strength. However, the stress caused from carrying rice husk still falls into the allowable range. A list of improvisations was made as a summary and evaluation guide and improvisation of Gasifier P2.

Abstrak :
This book offers recommendations on the milling processes for the carbon fiber reinforced plastic CFRP/Al2024. Due to the anisotropic and non-homogeneous structure of CFRP and the ductile nature of aluminum, the machining of this material is very challenging and causes various types of damage, such as matrix cracking and thermal alterations, fiber pullout and fuzzing during drilling and trimming, which affect the quality of machined surface. The book studies and models the machined surface quality of CFRP/Al2024 using a two-level full factorial design experiment. It describes the processes of trimming using down milling, and statistically and graphically analyzes the influence and interaction of cutting parameters. Lastly, the book presents the optimization of the cutting parameters in order to create a surface texture quality of CFRP/Al2024 to less than 1 µm.

Abstrak :
ABSTRACT
Additive manufacturing AM or formerly known as rapid prototyping RP has been evolving and improving in the past few decades. Industries have been slowly trying to implement AM as a mean to improve their business. The materials commercially used and the technology itself however are not as many and mature as expected. This project helps to develop an understanding of AM processes and the materials that could potentially use in the industry. The main focus of the project was to investigate the effect of thermal history during the AM process on the microstructure and mechanical properties of the sample. The approach to this project was to produce samples with different number of layers, and investigate the microstructure and hardness on the same layer for all samples. Before the commencing of the main project, the printing parameters of LENS 450 system were optimised first hand. The optimised printing parameters were of powder feed rate of 6rpm, laser scanning rate of 14ipm, and laser power of 300W. Using these optimised printing parameters, high quality samples were produced for the main project. It was concluded that there was a significant change on the hardness of the samples at different layer number. This indicates that there was different phases present in the microstructure of the samples, which are martensite and austenite.

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ABSTRAK
Manufaktur aditif atau yang sebelumnya lebih banyak dikenal dengan rapid prototype RP telah berkembang dan meningkat kualitasnya dalam beberapa dekade terakhir. Berbagai macam indsutri perlahan menerapkan manufaktur aditif sebagai sarana untuk meningkatkan kualitas bisnis mereka. Manufaktur aditif menggunakan bahan baku yang secara komersial dapat dengan mudah dicari dan teknologi yang cukup mudah untuk digunakan. Tujuan dari proyek ini adalah untuk membantu mengembangkan pemahaman proses manufaktur aditif dan pengolahan bahan baku yang berpotensi untuk digunakan di industry banyak. Fokus utama dari proyek ini adalah menyelidiki pengaruh sejarah termal selama proses manufaktur aditif pada struktur mikro dan kekerasan pada lapisan material yang sama di semua sampel. Parameter manufaktur aditif menggunakan system LENS 450 dioptimalkan pada tahap awal proyek. Parameter optimal untuk proses manufaktur aditif menggunakan bubuk baja H13 adalah 6pm untuk laju bahan baku, 14ipm untuk laju pemindaian laser, dan 300W untuk daya laser. Menggunakan parameter yang telah dioptimisasikan, sampel dengan kualitas yang tinggi diproduksi. Disimpulkan bahwa terjadi perubahan signifikan pada kekerasan sampel pada lapisan material yang berbeda di badan sampel. Perubahan signifikan dan nilai yang diperoleh untuk kekerasan sampel mengindikasikan bahwa struktur mikro didominasi oleh martensit dan austenit.