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Hasil Pencarian

Ditemukan 76 dokumen yang sesuai dengan query
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W. Setiawan
"Keberhasilan suatu proses pembentukan (forming) khususnya deep drawing baja lembaran untuk menghasilkan produk tertentu sangat ditentukan oleh sifat-sifat materialnya, walaupun juga masih sangat tergantung pada variabel-variabel proses pembentukan itu sendiri. Sifat mampu bentuk baja lembaran dingin sangat dipengaruhi oleh tekstur kristalografi. Komponen tekstur yang berpengaruh pada sifat mampu bentuk baja lembaran adalah (111)<112> dan (100)<110)>. Parameter yang banyak digunakan untuk menunjukkan sifat mampu bentuk baja lembaran dingin diperoleh dengan uji tarik. Yang menjadi ukuran adalah nilai rm. (koefesien anisotropi plastis normal). Walaupun dari uji ini data relatif cepat dan mudah diperoleh, namun data yang diperoleh kurang menunjukkan sifat yang sesungguhnya. Pengujian yang cukup p·opuler dan sering dipakai adalah cup drawing test. Pengujian ini menggunakan punch datar, yang berarti deep drawing murni. Besaran yang . menjadi ukuran deep drawability pada cup drawing test adalah Limiting Drawing Ratio (LDR). Dengan melakukan kedua pengujian ini, maka akan dapat diketahui hubungan yang lebih teknis dan praktis antara nilai rm dengan LDR. Perubahan variabel siklus anil (annealing) selalu ditujukan untuk mendapatkan sifat material (mampu bentuk, nilai rm) ke arah yang lebih baik. Dilain pihak perubahan sifat material akan diikuti dengan perubahan pada batas operasi deep drawing. Dengan demikian perlu diketahui pengaruh perubahan sifat mampu bentuk (nilai rm) terhadap perubahan batas operasi deep drawing. Percobaaan pada penelitian ini dilakukan dengan dua tahap. Tahap pertama adalah percobaan anil yang dimaksudkan untuk mendapatkan variasi sifat mampu bentuk. niiai rm· Percobaan kedua adalah deep drawing. Percobaan ini dilakukan umuk mendapatkan batas operasi deep drawing, yaitu gaya pemegang bakalan (Blank Holder Force, BHF) dan LDR. · Dari hasil percobaan menunjukkan, laju pemanasan lambat, temperatur tinggi dan waktu tahan lama, dapat menaikkan rasio tekstur (111)<112> tt'.rhadap (100)<110)>. Kenaikan rasio tekstur diikuti dengan kenaikan nilai rm dan LDR. Pada batas operasi deep drawing menunjukkan bahwa selang gaya pemegang bakalan menjadi lebih lebar pada kondisi anil laju pemanasan lambat, temperatur yang tinggi dan waktu tahan lama.

The success of a forming process especially a deep drawing produces a component depends on its material properties besides on forming process variables itself The formability of cold sheet steel very influenced by its crystallographic textures. The texture components that influence sheet steel formability are texture (111)<112> and (100)<110>. The parameters most widely used to showed cold sheet steel formability to be obtained by tension test. That is value of the normal plastic anisotropy coefficient, rm-value. Datum of this testing can be taken easily and faster but the result does not show the real of material properties. Another popular method is called cup drawing test. This test uses a flat bottom punch so it can be considered as pure deep drawing. On deep drawing test, deep drawability values are represented by limiting drawing ratio (LDR). By conducting these tests, more practical and technical relationship between rm-value with LDR can be understood. The changes of annealing cycle variables always aimed to get better material properties (formability, rm- value). In the other side, changes of material properties wili be followed by change of deep drawing operation limits. Therefore, it needs to be understood effect of changes of sheet steel formability (rm-value) on deep drawing operation limits. The experiment was divided into two stages. First stage is annealing simulation that means to get formability variation of sheet steels, rm-value. The second stage is deep drawing test to find out deep drawing operation limits, that are blank holder force, BHF and LDR. The results showed that slow heating rate, high temperature and prolonged holding time could increase texture intensity ratio (111)<112> to (100)<110>. The increase of texture ratio is followed by the increase of the rm-value and LDR. This annealing cycle pattern also makes the blank holder force range wider at the deep drawing operation limits.
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Depok: Fakultas Matematika dan Ilmu Pengetahuan Alam Universitas Indonesia, 2001
T39955
UI - Tesis Membership  Universitas Indonesia Library
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Nurhayati Indah Ciptasari
"Paduan kuningan 60Cu-40Zn merupakan paduan kuningan yang paling baik untuk diaplikasikan pada hot forming. Penelitian ini dilakukan untuk mengetahui perubahan struktur mikro dari rad brass bahan baku produk valve dengan perbedaan kandungan aluminium selelah dilakukan perlakuan panas. Perlakuan panas yang dilakukan yaitu annealing pada temperatur (450, 500 dan 550°C) dengan waktu holding selama I jam. Proses pendinginan dilakukan dengan menggunakan dua metode pendinginan. Metode pertama dengan menggunakan pendinginan lambat di udara terbuka. Sedangkan metode yang ke dua dengan pendinginan cepat pendinginan air) dengan media air. Pengujian yang dilakukan meliputi uji metalografi dan kekerasan. Hasil penelitian menunjukkan pada kondisi tanpa perlakuan, fraksi volume a benda uji Al rendah (64.8) lebih kecil daripada fraksi volume a benda uji rod Al tinggi (74.25). Fraksi volum alpha benda uji rod Al tinggi lebih besar daripada benda uji rod AI rendah. Sehingga hot formability benda uji rod Al rendah lebih baik daripada benda uji rod AI tinggi.Pada kondisi perlalman non quench, dengan meningkatnya temperatur annealing (450, 500 dan 550° C) pada benda uji rod Al rendah (0, 02%) maupun Al tinggi (0,2%) akan mengalami peningkaran fraksi volume an Sedangkan pada kondisi perlakuan quench, dengan meningkatnya temperatur annealing (450, 500 dan 55 0° C) pada benda uji rod Al rendah (0,02%) maupun Al tinggi (0,2%) akan mengalami penurunan fraksi volume a Pada pengujian kekerasan, dengan kondisi non quench, kenaikan temperatur annealing akan menurunkan nilai kekerasan pada benda uji AI rendah maupun benda uji Al tinggi. Pada benda uji Al terendah terjadi penurunan kekerasan dari 54 HRB (ranpa anil menjadi 42 HR5 (temperatur 550"). Sedangkan pada benda uji Al tinggi terjadi penurunan kekerasan dari 64 HR; (tanpa anil) menjadi 52 HR; (temperatur 550° C). Pada kondisi quench, temperatur annealing akan menurunkan nilai kekerasan pada benda uji A I rendah maupun benda uji Ai tinggi. Pada benda uji Al rendah terjadi penurunan kekerasan dari 54 HRH (tanpa anil menjadi 53 HR; temperatur 550°). Sedangkan pada benda uji Al tinggi terjadi penurunan kekerasan dan 64 HR; (tanpa anil, menjadi 58 HRB (temperatur 550°Q. Adanya peningkatan kadar Al dan Pb kemungkinan dapat menyebabkan retak setelah dilakukan forging."
Depok: Fakultas Teknik Universitas Indonesia, 2005
S41367
UI - Skripsi Membership  Universitas Indonesia Library
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Hidayat Winardi
Depok: Fakultas Teknik Universitas Indonesia, 1999
S49210
UI - Skripsi Membership  Universitas Indonesia Library
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Fatah Nurdin
Depok: Fakultas Teknik Universitas Indonesia, 1993
S39585
UI - Skripsi Membership  Universitas Indonesia Library
cover
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Ratnawati
"[ABSTRAK
Sintesis TiO2 bermorfologi nanotube array bentuk film (TNTAs) telah dilakukan dengan proses anodisasi logam Ti dalam larutan elektrolit gliserol yang mengandung NH4F, dilanjutkan dengan annealing untuk membuat fasa kristal dari TNTAs. Optimasi berbagai parameter meliputi variasi kadar air dalam larutan elektrolit, perlakuan annealing, penambahan NaBF4, metode dan lama pengadukan serta variasi loading dan metode dalam penambahan dopan logam Pt. Hasil SEM/FESEM menunjukkan bahwa TNTAs berhasil disintesis dengan tube yang rapi, tegak lurus dan mempunyai kisaran diameter dalam antara 49-205 nm, tebal dinding 11-33 nm serta panjang 530-2577 nm. Annealing dengan H2/Ar merupakan cara yang efisien untuk memasukkan dopan C, N dan B dalam matrik TNTAs secara insitu saat anodisasi, sehingga diperoleh penurunan energi band gap sampai pada kisaran 2,20?3,10 eV. Kebanyakan TNTAs berfasa anatase dengan ukuran kristal dari 18?33 nm. TNTAs yang disintesis pada kadar air 25% volume dan annealing dengan 20% H2/Ar merupakan fotokatalis optimal yang menghasilkan kerapatan arus tertinggi. Uji TNTAs untuk memproduksi hidrogen menggunakan gliserol sebagai sacrificial agent. Penambahan 5 mM NaBF4 selama anodisasi menghasilan TNTAs termodifikasi yang mampu menghambat laju rekombinasi elektron-hole sehingga dapat meningkatkan produksi hidrogen sebesar 32 %. Penambahan dopan Pt sebagai electron trapper secara fotodeposisi pada TNTAs hasil anodisasi ultrasonik mampu menghasilkan hidrogen dari larutan gliserol sebesar lima kali lebih tinggi dibandingkan tanpa penambahan Pt.;

ABSTRACT
Synthesis of TiO2 nanotube array (TNTAs) has been performed by anodization process of Ti metal in the glycerol electrolyte solution containing NH4F followed by annealing to induce crystallization. Optimization some parameters was done including the variation of water content in the electrolyte solution, annealing atmosphere, addition of NaBF4, mode of mixing, as well as the variation of loading and the methods of Pt addition on the TNTAs. SEM/FESEM analysis showed that well ordered and vertically oriented of TNTAs with inner diameters of 49-205 nm, wall thicknesses from 11 to 33 nm and lengths from 530 to 2577 nm were synthesized. Annealing with H2/Ar is found to be an efficient method for introducing dopant C, N and B into the lattice of TNTAs via insitu anodization and, therefore, the reducing band gap in the range of 2,20?3,10 eV can be obtained. Most of TNTAs have anatase phase with the crystalline size from 18 to 33 nm. Water content of 25 v% and annealing under H2/Ar of as-synt TNTAs showed optimal condition in producing the highest photocurrent density. The photocatalytic hydrogen production test was performed with glycerol as a sacrificial agent. The addition of 5 mM NaBF4 during anodization resulted modified TNTAs that can reduce recombination of electron-hole and showed up 32 % improvement in hydrogen production. The photodeposition of Pt on the TNTAs that obtained from ultrasonic anodization can enhance hydrogen production five times higher compare to the one with unplatinized TNTAs.;Synthesis of TiO2 nanotube array (TNTAs) has been performed by anodization process of Ti metal in the glycerol electrolyte solution containing NH4F followed by annealing to induce crystallization. Optimization some parameters was done including the variation of water content in the electrolyte solution, annealing atmosphere, addition of NaBF4, mode of mixing, as well as the variation of loading and the methods of Pt addition on the TNTAs. SEM/FESEM analysis showed that well ordered and vertically oriented of TNTAs with inner diameters of 49-205 nm, wall thicknesses from 11 to 33 nm and lengths from 530 to 2577 nm were synthesized. Annealing with H2/Ar is found to be an efficient method for introducing dopant C, N and B into the lattice of TNTAs via insitu anodization and, therefore, the reducing band gap in the range of 2,20?3,10 eV can be obtained. Most of TNTAs have anatase phase with the crystalline size from 18 to 33 nm. Water content of 25 v% and annealing under H2/Ar of as-synt TNTAs showed optimal condition in producing the highest photocurrent density. The photocatalytic hydrogen production test was performed with glycerol as a sacrificial agent. The addition of 5 mM NaBF4 during anodization resulted modified TNTAs that can reduce recombination of electron-hole and showed up 32 % improvement in hydrogen production. The photodeposition of Pt on the TNTAs that obtained from ultrasonic anodization can enhance hydrogen production five times higher compare to the one with unplatinized TNTAs., Synthesis of TiO2 nanotube array (TNTAs) has been performed by anodization process of Ti metal in the glycerol electrolyte solution containing NH4F followed by annealing to induce crystallization. Optimization some parameters was done including the variation of water content in the electrolyte solution, annealing atmosphere, addition of NaBF4, mode of mixing, as well as the variation of loading and the methods of Pt addition on the TNTAs. SEM/FESEM analysis showed that well ordered and vertically oriented of TNTAs with inner diameters of 49-205 nm, wall thicknesses from 11 to 33 nm and lengths from 530 to 2577 nm were synthesized. Annealing with H2/Ar is found to be an efficient method for introducing dopant C, N and B into the lattice of TNTAs via insitu anodization and, therefore, the reducing band gap in the range of 2,20–3,10 eV can be obtained. Most of TNTAs have anatase phase with the crystalline size from 18 to 33 nm. Water content of 25 v% and annealing under H2/Ar of as-synt TNTAs showed optimal condition in producing the highest photocurrent density. The photocatalytic hydrogen production test was performed with glycerol as a sacrificial agent. The addition of 5 mM NaBF4 during anodization resulted modified TNTAs that can reduce recombination of electron-hole and showed up 32 % improvement in hydrogen production. The photodeposition of Pt on the TNTAs that obtained from ultrasonic anodization can enhance hydrogen production five times higher compare to the one with unplatinized TNTAs.]"
2015
D2057
UI - Disertasi Membership  Universitas Indonesia Library
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Salamon, Peter, 1950-
"Simulated annealing has proved to be an easy and reliable method for finding optimal values of a problem in cases where there is no road map to possible solutions. Facts, Conjectures, and Improvements for Simulated Annealing offers an introduction to this topic for novices and provides an informative review of the area for the more expert reader. This book brings together for the first time many of the theoretical foundations for improvements to algorithms for global optimization that until now existed only in scattered research articles.
The method described in this book operates by simulating the cooling of a (usually fictitious) physical system whose possible energies correspond to the values of the objective function being minimized. The analogy works because physical systems occupy only states with the lowest energy as the temperature is lowered to absolute zero."
Philadelphia: Society for Industrial and Applied Mathematics, 2002
e20450547
eBooks  Universitas Indonesia Library
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Niken Sudorowerdi
"ABSTRAK
Kandungan garam di dalam air laut dapat dikurangi konsentrasinya, melalui proses osmosa balik. Osmosa balik adalah proses pemisahan zat-zat dalam larutan dengan cara permeasi di bawah tekanan melalui membran yang sesuai.
Penelitian ini bertujuan untuk membuat membran dengan menggunakan bahan dasar nilon-6 dan menentukan pengaruh annealing terhadap karakterisasi membran. Membran nilon-6 dapat dibuat dengan cara mencampurkan nilon-6, asam format, dan formamida. Campuran tersebut diaduk, dilanjutkan dengan proses pencetakan, penguapan, pencelupan dalam air, dan memvariasi kondisi pemanasan (annealing). Membran yang dihasilkan diuji harga penolakan garam, kecepatan aliran, kandungan air, kuat regang dan perpanjangan putus, serta melihat pori-pori membran yang dihasilkan dengan menggunakan SEM.
Dari hasil penelitian dapat disimpulkan bahwa semakin tinggi temperatur annealing, dan pada kisaran waktu annelaing antara 5 sampai dengan 10 menit, semakin tinggi temperatur dan semakin lama waktu annealing, maka besarnya harga penolkan garam, kuat regang dan perpanjangan putus meningkat, sedangkan kecepatan aliran dan kandungan air menurun."
Depok: Fakultas Matematika dan Ilmu Pengetahuan Alam Universitas Indonesia, 1994
S-Pdf
UI - Skripsi Membership  Universitas Indonesia Library
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Fedy Alberto
"ABSTRAK
Dengan berjalannya program pemerintah untuk mengkonversi penggunaan minyak tanah bersubsidi ke LPG 3 kg, pertamina memerlukan rancangan rute distribusi yang efektif di dalam jalur distribusi LPG 3 kg agar dicapai efisiensi dari total biaya pengankutan LPG dari Depok ke stasiun pengisian LPG 3 kg. permasalahan perancangan rute distribusi LPG disini merupakan model multi depot transportation problem dengan split service (MDTPSS) dan akan diselesaikan menggunakan metode Simulated annealing. dengan menggunakan metode ini diharapkan output dari penerimaan ini adalah model matematis untuk penentuan rute distribusi LPG dari Depok ke stasiun pengisian LPG 3 kg yang optimal.

ABSTRACT
With the government program running to convert the use of subsidized kerosene to 3 kg LPG, Pertamina requires the design of an effective distribution route in the 3 kg LPG distribution line in order to achieve the efficiency of the total LPG shipping cost from Depok to the 3 kg LPG filling station. the problem of designing LPG distribution routes here is a multi depot transportation problem model with split service (MDTPSS) and will be solved using the Simulated annealing method. by using this method it is expected that the output of this revenue is a mathematical model for determining the LPG distribution route from Depok to the optimal 3 kg LPG filling station."
2011
T29580
UI - Tesis Open  Universitas Indonesia Library
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Dedi Priadi
"Purpose of Research (specific objective and/or statement of hypothesis in around 300 to400 words. Please try to avoid using an additional page). Zry-4 is an alloy of Ziconium (Zr) with alloying elements of Fe,Cr, and Sn with weight percentage of 0.2%, 0.07% and 1.5% respectively. This alloying element addition is intended to improve the mechanical properties as well as Zirconium, that is corrosive resistance at high temperature. Besides the alloying elements, the micro structural morphology of Zry-4, as results of thermomechanic treatment process, also an active role to determine mechanical, physical and corrosion properties. This alloy is used as structure and cladding materials for Pressurized water Reactor (PWR) nuclear fuel element. Zirconium alloy of Zr-702 will also be used for chemical engineering devices due to its high corrosion resistance in acid and alkali liquid as well as at high temperature. Examples of device are : Distillation Column, Reactor, Pump Housing and Heat exchanger and Heating coil due to mechanical properties at high temperature.
Some researchs have been done previously to observe changes of mechanical and corrosive properties of Zry-4 with solution treatment 0-phase, but unfortunately they are not continued between deformation degree and grain size with new precipitate is obtained.In this research we plan to carry out a cold deformation process of 0-quenching result and be continued with annealing process. From the process results we will observe the morphology of micro structure of Zry-4. This process will enable to determine the deformation level, time and temperature annealing to obtain a certain microstructure according to the desired mechanical properties (Microhardness).
Results of research can hopefully be used as input in the working process of Zry-4.Optical Microscopy, Transmission Electron Microscopy and X-Ray Diffraction will be used in the microstructure observation."
Depok: Fakultas Teknik Universitas Indonesia, 1995
LP-Pdf
UI - Laporan Penelitian  Universitas Indonesia Library
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