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Ditemukan 50 dokumen yang sesuai dengan query
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New York: Academic Press, 1982
547.84 ELE
Buku Teks  Universitas Indonesia Library
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Falah Putra Caesarianto
"Perkembangan terkini dari semen ionomer kaca (SIK) telah menjadikannya sebagai sebuah bahan restorasi gigi yang sangat baik, namun sifat mekaniknya masih perlu ditingkatkan. Sifat mekanik dari semen ionomer kaca dapat ditingkatkan melalui inkorpoasi kristal nano fluorhidroksiapatit, salah satu mineral penyusun jaringan keras gigi sehingga memiliki biokompatibilitas yang baik. Penelitian ini bertujuan untuk mensintesis kristal nano fluorhidroksiapatit dengan tingkat fluoridasi yang berbeda melalui metode yang cepat dan efisien serta mengevaluasi pengaruh penambahan kristal nano fluorhidroksiapatit terhadap kekerasan mikro semen ionomer kaca yang telah dimodifikasi melalui inkorporasi kristal nano fluorhidroksiapatit. Kristal nano fluorhidroksiapatit dengan tingkat fluoridasi 0 hingga ~95% disintesis melalui metode presipitasi yang dibantu iradiasi gelombang mikro. Fase kristal, gugus fungsi, morfologi permukaan, dan tingkat fluoridasi dari bubuk yang telah disintesis ditentukan melalui difraksi sinar-X (XRD), spektroskopi inframerah transformasi Fourier (FTIR), mikroskop pemindai elektron (SEM), dan energy dispersive x-ray spectrometer (EDX) secara berturut-turut. Kemudian, bubuk fluorhidroksiapatit yang telah disintesis ditambahkan ke dalam semen ionomer kaca komersial (Fuji IX, GC Gold Label) dengan jumlah sebanyak 5 wt%, 7,5 wt%, dan 10 wt%. Semen ionomer kaca yang tidak mengalami penambahan fluorhidroksiapatit digunakan sebagai kelompok kontrol. Kekerasan mikro dari semen yang telah dikondisikan selama 24 jam di dalam air distilasi bersuhu 37 °C dievaluasi dengan penguji kekerasan mikro Vickers. Metode karakterisasi menunjukkan bahwa bubuk yang telah disintesis merupakan fluorhidroksiapatit berukuran nano dengan tingkat fluoridasi yang berbeda. Kekerasan mikro dari semen yang dimodifikasi menunjukkan nilai yang lebih tinggi (54-100 HV) dibanding kelompok kontrol (48,94 HV). Hasil menunjukkan bahwa penambahan fluorhidroksiapatit dengan tingkat fluoridasi yang berbeda pada penambahan sebanyak persentase massa yang sama tidak menghasilkan perbedaan signifikan pada kekerasan mikro semen yang dimodifikasi. Selain itu, kekerasan mikro dari semen yang dimodifikasi akan meningkat dengan penambahan fluorhidroksiapatit maksimum sebanyak 7,5 wt% dan kemudian berkurang dengan penambahan lebih lanjut.

Recent developments of glass ionomer cement (GIC) have made it to become an excellent dental restorative material, nevertheless, its mechanical properties still need to be improved. The mechanical strength of glass ionomer cement could be enhanced through the incorporation of fluorhydroxyapatite nanocrystal, one of the minerals that compose dental hard tissues and therefore have great biocompatibility. This study aims to synthesize fluorhydroxyapatite with different degrees of fluoridation through a fast and efficient method and to evaluate the effect of fluorhydroxyapatite nanocrystals addition to the microhardness of glass ionomer cement modified by the incorporation of fluorhydroxyapatite nanocrystals. Fluorhydroxyapatite nanocrystals with 0 to ~95% fluoridation degrees were synthesized through a microwave-assisted precipitation method. The crystal phase, functional groups, surface morphology, and fluoridation degrees of the synthesized powder were determined through X-Ray Diffraction (XRD), Fourier Transform Infrared (FTIR) Spectroscopy, Scanning Electron Microscopy (SEM), and Energy Dispersive X-ray (EDX) Spectroscopy, respectively. Thereafter, synthesized fluorhydroxyapatite powder was added to commercial glass ionomer cement (Fuji IX, GC Gold Label) with an amount of 5 wt%, 7.5 wt%, and 10 wt%. The glass ionomer cement which did not undergo fluorhydroxyapatite addition was used as the control group. The microhardness of the cement which has been conditioned for 24 hours in distilled water at 37 °C were evaluated with Vickers Microhardness Tester. Characterization methods revealed that the synthesized powder was nano-sized fluorhydroxyapatite with different degrees of fluoridation. The microhardness of the modified cement exhibited higher values (54-100 HV) compared to the control group (48.94 HV). The results showed that the difference in fluoridation degrees of fluorhydroxyapatite at the addition of the same mass percentage did not produce a significant difference in the microhardness among the modified cement. On the other hand, the microhardness of the modified cement would increase with the addition of fluorhydroxyapatite maximum at 7.5 wt% addition, and then decreases with further addition."
Depok: Fakultas Matematika dan Ilmu Pengetahuan Alam Universitas Indonesia, 2021
S-pdf
UI - Skripsi Membership  Universitas Indonesia Library
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Iyon Suyana
Depok: Fakultas Matematika dan Ilmu Pengetahuan Alam Universitas Indonesia, 2003
T40037
UI - Tesis Membership  Universitas Indonesia Library
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Ahmad Faridh
Depok: Fakultas Matematika dan Ilmu Pengetahuan Alam Universitas Indonesia, 2004
T39730
UI - Tesis Membership  Universitas Indonesia Library
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Hari Prabowo
Depok: Fakultas Teknik Universitas Indonesia, 1993
S38364
UI - Skripsi Membership  Universitas Indonesia Library
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Solymar, L.
USA: Oxford University Press, 2010
620.112 SOL e
Buku Teks SO  Universitas Indonesia Library
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M. Ekaditya Albar
"Pelat bipolar merupakan komponen penting di dalam Polymer Electrolyte Membrane Fuel Cell (PEMFC) yang berfungsi untuk mengumpulkan dan memindahkan elektron dari anoda ke katoda. Pelat bipolar berbasis komposit terdiri dari grafit sintetis (MERCK) dan carbon black sebagai filler serta resin epoksi dan hardener sebagai binder. Carbon black dibuat dari pembakaran serabut kelapa pada suhu 500°C dan 900°C dalam kondisi inert. Pembahasan utama pada penelitian ini adalah menganalisis pengaruh variasi komposisi ukuran partikel carbon black sebagai variabel pertama dan lama pencampuran grafit dan carbon black dalam media air sebagai variabel kedua, terhadap distribusi sifatsifat pelat bipolar PEMFC berbasis komposit epoksi/grafit. Komposisi ukuran partikel carbon black hasil milling dengan rotary ball mill selama 2 hari berbanding 4 hari pada penelitian ini, yaitu 5:95, 10:90, 15:85 dan 20:80. Lama pencampuran antara grafit dan carbon black divariasikan dari 1 jam, 2 jam, 3 jam dan 4 jam dengan alat hand mixer di dalam media air. Pelat bipolar dicetak dengan metode compression molding dengan tekanan 55 MPa selama 4 jam pada suhu 100oC. Karakterisasi pelat bipolar meliputi pengujian konduktivitas listrik, pengujian fleksural, pengujian densitas, pengujian porositas, analisis gugus fungsional dengan FTIR dan pengamatan permukaan patahan fleksural menggunakan FE-SEM. Hasil penelitian menunjukkan bahwa komposisi optimal ukuran partikel carbon black hasil milling 2 hari dan 4 hari dengan perbandingan 15:85 pada lama pencampuran 3 jam dalam media air menghasilkan pelat bipolar dengan karakteristik nilai konduktivitas tertinggi sebesar 1.06 S/cm, kekuatan fleksural 48.38 MPa, densitas 2.50 gr/cm3 dan porositas 0.70%.

Bipolar plate is one of main components in Polymer Electrolyte Membrane Fuel Cell (PEMFC) that collects and transfers electron from anode to cathode. Bipolar plate composites consist of syntetic graphite (MERCK) and carbon black (CB) as filler material. Epoxy resin and hardener was used as binder material of the composite. Carbon black was prepared from combustion of palm fiber in 500 and 900°C through inert atmosphere. The main discussion in this research is to investigate the influence of variations in composition of carbon black particle size and mixing time of graphite and carbon black to the distribution of properties of PEMFC bipolar plates based on graphite/epoxy composite. Particle size composition ratio of milled carbon black in 2 days and 4 days are 5:95, 10:90, 15:85 and 20:80. Variation in mixing time of graphite and carbon black are 1 hour, 2 hours, 3 hours and 4 hours with water as mixing media. Characterization of bipolar plate material includes electrical conductivity test. flexural test, density and porosity measurement, functional groups analysis using FTIR and fracture surface examination using FE-SEM. The optimum composition was obtained in ratio of 2 days milled-CB : 4 days milled-CB in range of 15:85 and 3 hours mixing time using water. The optimum electrical conductivity, flexural strength, density and porosity were respectively: 1.06 S/cm, 48.38 MPa, 2.50 gr/cm3 and 0.70%."
Depok: Fakultas Teknik Universitas Indonesia, 2013
T33734
UI - Tesis Membership  Universitas Indonesia Library
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Universitas Indonesia, 2005
TA724
UI - Tugas Akhir  Universitas Indonesia Library
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"A reference listing the electrical and magnetic properties of metals. Each data entry includes the material's name, temper, UNS number, property values in SI and alternate units, and a source of the data. DLC: Metals--Electric properties."
Materials Park, Ohio: ASM International, 2000
e20442503
eBooks  Universitas Indonesia Library
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Irma Saraswati
"ABSTRACT
A good justification for gallium nitride on silicon is a potential for optoelectronic integrated circuits, and its low cost has stimulated the growth of GaN on large size wafers. The application interest for GaN/Si is power electronics. This current work focuses on characterization optical, electro-optical, and microstructural and simulation design of GaN/Si channel waveguide. For the characterization of GaN microstructure, we use SEM, TEM, AFM, and XRD to observe layer thickness, material structure, material roughness, and crystalline quality of materials. Using the guided wave prism coupling technique, we have fully established the index dispersion and, thickness of GaN at room temperature, as well as its surface roughness based on AFM characterization. Futhermore, the thermal dependence of GaN at ordinary and extraordinary refractive indices are determined to be at 1.227 10-5/ K and 1.77 10-5/ K, respectively. The thermal dependence of GaN shows better value than GaAs at the wavelength range of 0.4 - 1.5 m. It has a slightly low-temperature dependence. Results demonstrate that excellent waveguide properties of GaN on silicon with an optical propagation loss of GaN/Si at 633 nm is 2.58 dB/cm, which is higher than the propagation loss of GaN/sapphire at around 1.34 dB/cm. The roughness of GaN/Sapphire and GaN/Si samples have been identified at the range 1.6 - 5.2 nm and 9.6 - 13 nm, respectively. The birefringence of GaN/Si is negative within the range of -0.16 x10-2 to -6.06x10-2. This negative value means that the polarization of the wave is parallel to the optical axis. Electrooptic constants r13 = 1.01 pm/V and r33 = 1.67 pm/V are higher than those obtained for III-V GaAs semiconductors. We compared the results on Si with those on sapphire. Based on a numerical simulation using OptiBPM, the design result has single mode output with 1 m thickness layer of SiO2 at the planar waveguide design, while the channel waveguide design has 1 m thickness layer of GaN. The simulated result that the maximum power output approximately 50- 58 at the plannar and rib waveguide design.

ABSTRAK
A good justification for gallium nitride on silicon is a potential for optoelectronic integrated circuits, and its low cost has stimulated the growth of GaN on large size wafers. The application interest for GaN Si is power electronics. This current work focuses on characterization optical, electro optical, and microstructural and simulation design of GaN Si channel waveguide. For the characterization of GaN microstructure, we use SEM, TEM, AFM, and XRD to observe layer thickness, material structure, material roughness, and crystalline quality of materials. Using the guided wave prism coupling technique, we have fully established the index dispersion and, thickness of GaN at room temperature, as well as its surface roughness based on AFM characterization. Futhermore, the thermal dependence of GaN at ordinary and extraordinary refractive indices are determined to be at 1.227 10 5 K and 1.77 10 5 K, respectively. The thermal dependence of GaN shows better value than GaAs at the wavelength range of 0.4 1.5 m. It has a slightly low temperature dependence. Results demonstrate that excellent waveguide properties of GaN on silicon with an optical propagation loss of GaN Si at 633 nm is 2.58 dB cm, which is higher than the propagation loss of GaN sapphire at around 1.34 dB cm. The roughness of GaN Sapphire and GaN Si samples have been identified at the range 1.6 5.2 nm and 9.6 13 nm, respectively. The birefringence of GaN Si is negative within the range of 0.16 x10 2 to 6.06x10 2. This negative value means that the polarization of the wave is parallel to the optical axis. Electrooptic constants r13 1.01 pm V and r33 1.67 pm V are higher than those obtained for III V GaAs semiconductors. We compared the results on Si with those on sapphire. Based on a numerical simulation using OptiBPM, the design result has single mode output with 1 m thickness layer of SiO2 at the planar waveguide design, while the channel waveguide design has 1 m thickness layer of GaN. The simulated result that the maximum power output approximately 50 58 at the plannar and rib waveguide design."
2016
D2035
UI - Disertasi Membership  Universitas Indonesia Library
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