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Abstrak :
ABSTRAK
Penelitian telah dilaksanakan di Laboratorium Pusat Pramuteknik Petrokimia PERTAMINA dan Laboratorium XRD Jurusan Fisika Universitas Indonesia. Percobaan dilakukan dengan peralatan dan mesin-mesin dalam Skala semi industri.

Bahan plastik yang berbentuk pelet diekstrusi menjadi lembaran, dan dipotong-potong menjadi pita. Pita-pita ini kemudian diorientasi dalam media air panas dengan variasi :berikut :

1. Ratio penarikan (Draw ratio, DR) dari 5 sampai 7,5 dengan suhu orientasi konstant 98°C. Suhu dari 60°C sampai 98°C dengan ratio penarikan konstan 6.

2. Pengukuran sifat fisik dari pita yang telah diorientasi meliputi denier, kuat tarik, mulur dan densitas, sedangkan sifat termal diukur dengan alat Differential Scanning Calorimeter dan titik leleh diukur dengan alat Thermovar.

3. Pengukuran derajat kristalinitas dan derajat keteraturan struktur kristal menggunakan alat Difraksi Sinar X.

Hasil penelitian menunjukkan bahwa kenaikan derajat kristalinitas akibat proses orientasi menyebabkan terjadinya peningkatan linier sifat fisik dan termal.

Abstrak :
Zirkonium-Niobium paduan (Zr-Nb paduan) memiliki potensi untuk menggantikan implant Titanium kontemporer dengan mempertimbangkan sitotoksisitas nya, suseptibilitas magnetik dan ketahanan korosi. Metalurgi serbuk sebagai salah satu metode pembentukan dapat digunakan dalam produksi implant dengan desain rumit dan struktur mikro yang fleksibel, baik dalam komposisi dan porositas. Pemadatan dan sintering dilakukan untuk menghasilkan produk yang padat dengan porositas. Pengamatan morfologi porositas akan diamati dengan mikroskop optik dan jumlah porositas dalam paduan akan diamati dengan pengujian porositas. Sedangkan struktur kristal diamati dengan dan X-Ray Diffraction (XRD). Konstituen fasa mikro sangat tergantung pada komposisi Niobium. Pengujian kekerasan menunjukkan peningkatan seiring dengan penambahan jumlah Niobium. Sementara itu penambahan Niobium akan menurunkan jumlah porositas dan mengubah morfologi porositas menjadi berbentuk jaring. Penambahan Niobium dalam jumlah besar membutuhkan temperature sintering yang jauh lebih tinggi dibandingkan paduan dengan jumlah Niobium lebih kecil. ......Zirconium-Niobium alloy (Zr-Nb alloy) has potency to replace the contemporary Titanium bioimplant by considering its cytotoxicity, magnetic susceptibility and corrosion resistance. Powder metallurgy as one of the forming methods could be used in production of bioimplant with intricate design and flexible microstructure, both in composition and porosity. Compaction and sintering is carried out to produce solid product with remained porosity. Resulting porosity of Zr-Nb alloy produced by powder metallurgy method will be characterized by density measurements and optical microscopy. Crystalline structure is observed by X-Ray Diffraction (X-RD). The microphase constituent is highly dependent on Niobium composition. The density of alloy will decrease as the addition of Niobium. In contrary, the hardness of alloy will increase as the addition of Niobium.

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Sel surya telah melalui berbagai tahap pengembangan. Silikon merupakan salah satu bahan utama dalam komersialisasi sel surya. Sel surya crystalline silicon heterojunction with intrinsic thin layer HIT merupakan salah satu aplikasi silikon yang berhasil menghasilkan efisiensi tinggi. Alternatif lain yang bisa dilakukan adalah dengan menggabungkan silikon dengan material compound III-V atau disebut sebagai sel surya crystalline silicon heterojunction with compound thin layer HCT. Sel surya crystalline silicon HCT mampu memberikan alternatif, baik dari segi fabrikasi maupun efisiensi, dibandingkan dengan sel surya crystalline silicon HIT. n-AlGaAs digunakan sebagai alternatif dari n-AlAs pada sel surya crystalline silicon HCT. Jika dibandingkan dengan AlAs, AlGaAs mempunyai nilai lattice constant yang lebih sesuai dengan silikon. Penggunaan metode step grading pada material AlxGa1-xAs dilakukan dengan tujuan untuk meningkatkan efisiensi sel surya. Rancangan sel surya crystalline silicon HCT dilakukan dengan menggunakan perangkat lunak wxAMPS. Dari hasil simulasi didapat arus hubung singkat Jsc sebesar 16,64 mA/cm2; tegangan hubung terbuka Voc sebesar 1,05 V; fill factor sebesar 95,09 ; dan efisiensi 16,64 . Selain itu hasil simulasi menunjukkan penggantian tipe doping dari tipe p ke tipe n menghasilkan kenaikan efisiensi lebih besar pada sel surya HCT n-AlGaAs terhadap sel surya HCT p-AlGaAs, yaitu 11,84 ; sedangkan nilai fill factor mengalami kenaikan sebesar 16,05. ...... Solar cell has been through many development phases. Silicon is a one of many important material in solar cell manufacturing. Heterojunction with intrinsic thin layer HIT crystalline silicon solar cell is one of silicon solar cell applications, which can produce high efficiency. An alternative to HIT crystalline silicon solar cell is Heterojunction with compound thin layer HCT crystalline silicon solar cell where silicon is coupled with III V semiconductor compound. HCT crystalline silicon solar cell could be an alternative either from fabrication process or efficiency value compared to HIT crystalline silicon solar cell. n AlGaAs is used as an alternative from n AlAs on HCT crystalline silicon solar cell. Compared to AlAs, lattice constant of AlGaAs is more suitable to the silicon. Step grading method is used for AlxGa1 xAs surface to increase solar cell efficiency. wxAMPS is used as simulation tool to achieve maximum design optimization for HCT crystalline silicon solar cell. Simulation results show that HCT crystalline silicon solar cell produce short circuit current Jsc value is 16.64 mA cm2, open circuit voltage Voc value is 1.05 V, fill factor value is 95.09, and efficiency value is 16.64. Simulation also shows a change from p type to n type dopant, result a significant efficiency increase for HCT n AlGaAs solar cell compared to HCT p AlGaAs solar cell, which is 11.84, in conjunction with its fill factor value, which increase 16.05.

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Kristal TiO2 anatase dipreparasi dengan proses hidrotermal pada suhu 240°C dari prekursor titanium tetraisopropoksida (TTIP) dalam larutan alkohol/air pada suasana asam. TiO2 hasil sintesis dikarakterisasi dengan X-Ray Diffractometer (XRD), Diffuse Reflectance Spectrophotometry (DRS), Particle Size Analyzer (PSA) dan Fourier Transform Infra Red Spectrophotometry (FTIR). Hasil karakterisasi menunjukkan bahwa TiO2 yang dipreparasi secara hidrotermal mempunyai bentuk kristal anatase dengan ukuran kristal 10 nm, celah energy sebesar 3,33 eV dan distribusi ukuran partikel (0,726m - 1,47 6m dan 15,30 6m - 111,09 6m). Proses kalsinasi terhadap TiO2 hidrotermal mengakibatkan pertumbuhan inti dan menginduksi transformasi dari fasa kristal anatase menjadi rutile. Akibatnya proses kalsinasi menghasilkan campuran kristal anatase dan rutile, masing-masing dengan ukuran kristal 11 nm dan kristal rutile 12 nm, celah energy sebesar 3,29 eV dan distribusi ukuran partikel (0,576m - 1,51 6m dan 31,32 6m - 170,28 6m). Serbuk TiO2 hasil sintesis dihaluskan dan didispersikan dalam air. Evaluasi dispersi TiO2 dilakukan dengan variasi pH, variasi konsentrasi PEG 1000, dan variasi pH pada konsentrasi PEG 1000 tertentu. Absorbansi hasil dispersi TiO2 setelah 24 jam diukur dengan spektrofotometer UV-Vis. Kestabilan dispersi TiO2 optimum dengan mekanisme sterik dicapai pada konsentrasi PEG 1000 0,05%, sedangkan berdasarkan mekanisme elektrostatik didapatkan kestabilan optimum pada pH 9. Dispersi TiO2 digunakan untuk menyiapkan immobilisasi film TiO2 pada pelat kaca dengan cara spraying dan digunakan untuk evaluasi aktivitas fotokatalitik. Evaluasi aktivitas fotokatalitik TiO2 hasil sintesis dilakukan dengan cara melihat kemampuan degradasinya terhadap larutan Methylene blue. Pengukuran dilakukan dengan tiga kondisi yang berbeda yaitu fotokatalisis, fotolisis, dan katalisis. Hasil dari ketiga kondisi ini membuktikan bahwa degradasi terbesar terjadi pada kondisi fotokatalisis dengan pseudo orde pertama dimana laju reaksinya, k, sebesar 9,68.10-3 menit-1. ......Titanium tetraisopropoxide (TTIP) precursor in acidic ethanol/water solution was used to prepare TiO2 anatase crystal by hydrothermal reaction at 240°C. Prepared TiO2 was characterized by X-Ray Diffractometer (XRD), Diffuse Reflectance Spectrophotometry (DRS), Particle Size Analyzer (PSA) and Fourier Transform Infra Red Spectrophotometry (FTIR). Characterization results indicate that prepared TiO2 has an anatase form (crystallite size 10 nm), band gap of 3.33 eV, and an aggregate nature (0.726m - 1.47 6m dan 15.30 6m - 111.09 6m). A calcinations process to the TiO2 powder leads to grain growth and induce phase transformation from anatase to rutile. As consequence, calcinations process produced anatase phase (crystallite size 11 nm) and rutile phase (crystallite size 12 nm), band gap 3.29 eV, and an aggregate nature (0.576m - 1.51 6m dan 31.32 6m - 170.28 6m). The TiO2 hydrothermal powder was subjected to a ball milling and dispersed in water. The TiO2 dispersion stability was evaluated under variations of pH, PEG 1000 concentration, and pH at a certain PEG 1000 concentration. The turbidity of dispersions were observed by UV-Vis spectrophotometer after 24 hours. Optimum stability of TiO2 dispersion by steric mechanism was obtained at PEG 1000 0.05%, while by electrostatic mechanism at pH 9. This water base TiO2 dispersion was used to prepared TiO2 film on glass plate by spraying method and was used for photocatalytic activity evaluation toward methylene blue degradation The observations were conducted at three experimental conditions, namely photocatalytic, photolytic, and catalytic. The results revealed that the highest degradation was obtained at photocatalytic condition, with rate constant, k, is 9.68 x 10-3 min-1, and apparently follows pseudo-first-order reaction.

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Material quarternair CuGaSeTe and CuGa0.5In 0.5Te2 merupakan material dasar yang digunakan dalam fabrikasi solar sel. Material tersebut memiliki koefisien absorpsi yang tinggi sekitar 103 ? 105 cm-1 dan rentang energi gap 1-5 eV. Pada penelitian ini telah dibuat lapisan tipis dengan menggunakan metode evaporasi Flash dari butiran-butiran quarternair material CuGaSeTe and CuGa0.5In 0.5Te2 yang dievaporasi agar menempel di substrat kaca. Setelah lapisan tipis diperoleh kemudian dilakukan karakteristik optik dan listrik lapisan tipis tersebut. Spektroskopi X-Ray Diffraction (XRD) digunakan untuk memperoleh parameter kisi dan struktur kristal lapisan tipis tersebut. Hasil XRD memperlihatkan bahwa struktur lapisan tipis CuGaSeTe and CuGa0.5In 0.5Te2 adalah chalcopyrite. Koefisien absorpsi dan energi gap lapisan tipis dihitung dari pola kurva transmitansi dan reflektansi hasil pengukuran difraktrometer UVVIS. Dengan menggunakan Energy Dispersive Spectroscopy (EDS), komposisi lapisan tipis dapat diketahui, sedangkan dengan menggunakan Hall Effect dapat dihitung resistivitas, mobilitas dan pembawa muatan mayoritas lapisan tipis CuGaSeTe and CuGa0.5In 0.5Te2.

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Quarternair CuGaSeTe and CuGa0.5In 0.5Te2 Thin Films Fabrication Using Flash Evaporation. Quarternair materials CuGaSeTe and CuGa0.5In 0.5Te2 are the basic materials to solar cell fabrication. These materials have high absorption coefficients around 103 ? 105 cm-1 and band gap energy in the range of 1-5 eV. In this research, the films were made by flash evaporation method using quarternair powder materials of CuGaSeTe and CuGa0.5In 0.5Te2 to adhere in a glass substrate. After the films were obtained, the properties of these films will be characterized optically and electrically. The lattice parameter of the films and the crystalline film structure were obtained using X-Ray Diffraction (XRD) spectroscopy. The XRD results show that the quarternair CuGaSeTe and CuGa0.5In 0.5Te2 films have a chalcopyrite structure. The absorption coefficient and the band gap energy of the films were calculated using transmittance and reflectance patterns that measured using UV-VIS Difractometer. The films composition can be detected by using the Energy Dispersive Spectroscopy (EDS), while the films resistivity, mobility and the majority carrier of the films were obtained from Hall Effect experiments.

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ABSTRACT
The combination of the coupled mode and normal mode theories has been used to formulaic the theoretical performance represented by the coupling length and crosstalk parameters of the X-cut APE-LN SDC fabricated using the benzoic acid as the proton source, where in this case the matrix effective refractive index (MERI) method is applied for solving the symmetric and antisymmetric propagation constants of the normal modes propagating in this device. The corresponding near field method has been used to experimentally determine its crosstalk.

The actual performance of this device is characterized by comparing the theoretically calculated with the experimentally determined crosstalk parameters. A software computer program has been developed in order to numerically characterize the entire characteristic and performance of the SDC under study.

For the SDC under study, the best crosstalk obtained at the operating wavelength lamda =1.3 micrometer is ~0.21 dB for the interaction length L = 6 mm and the gap separation g = 5 mm. Its coupling length is ~ 1.33 mm. The propagation constant of the corresponding individual single-mode X-cut APE-LN channel waveguide making up this SDC is beta = 10.37901 micrometer, and thereby its effective refractive index is N cπ= 2.14743330.

It has been shown that the fabricated SDC is very lossy. It has been deduced that its bad performance predominantly caused by the side diffusion effect, corresponding to the fabrication problem, where in this case the substrate sample has been not coated first with the buffer layer when the deposition of substrate sample with the aluminum mask was to be performed in the fabrication stages.

Moreover, in this case only the simple annealing has been performed. The successive annealing process in order to reduce the coupling loss has been not applied yet. Under the assumption that the fabrication tolerances are such that the practical devices with coupling loss below 0.25 dB are feasible, the fabricated SDC under study is a 3 dB coupler.

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[Pada penelitian ini, serat ijuk dihancurkan dan diayak ukuran 40 # setelah itu serat ijuk diberi perlakuan kimia dengan NaOH 2 % selama 1 jam, KMnO4 0,1 N selama 15 menit, dan NaClO 5 % selama 5 jam dengan tujuan mendapatkan selulosa kristalin. Setelah itu dilakukan proses pencampuran kering (hotmelt mixing) antara polipropilen dengan serat ijuk hasil perlakuan kimia dengan 7,5 % volum serat ijuk terhadap polipropilen dengan variabel temperatur 160°C, 165°C, dan 170°C dan variabel waktu pencampuran 15 menit dan 20 menit. Setelah itu dilakukan pengujian uji FTIR buat serat, sedangan buat komposit adalah uji tarik, uji STA, uji XRD, dan uji FE-SEM hal ini dilakukan untuk mendapatkan sifat kristalinitas dan mekanik dari komposit polipropilen ini. Hasil penelitian menunjukkan bahwa serat ijuk hasil perlakuaan lebih kristalin dari pada serat ijuk tanpa perlakukan, polipropilen dengan serat ijuk hasil perlakuaan kimia cukup kompatibel terhadap polipropilen, dari penelitian didapatkan sifat kristalinitas terbaik pada variabel 165°C selama 20 menit. Dan yang memiliki sifat kekuatan tarik paling baik adalah variabel 170°C selama 20 menit, sedangkan yang memiliki % elongasi paling baik adalah dengan variabel 160°C 20 menit. ......In this work, palm fiber crushed and sieved size 40 # after the palm fiber chemically treated with 2% NaOH for 1 hour, 0.1 N KMnO4 for 15 minutes, and 5% NaClO for 5 hours in order to obtain crystalline cellulose. Once that is done the dry mixing (hotmelt mixing) between polypropylene and palm fiber chemical treatment results with 7.5% volume of the palm fiber and polypropylene with a variable temperature of 160°C, 165°C and 170°C and a variable time mixing 15 minutes and 20 minutes. After it was examined FTIR test for fiber, while the composite is made tensile test, STA test, XRD test and FE-SEM test this is done to obtain crystallinity and mechanical properties of polypropylene composites this. The results show that fiber perlakuaan results more crystalline fibers than untreated palm fiber, polypropylene and palm fiber chemistry results treatment compatible enough to polypropylene, crystallinity of the research showed the best properties on the variable 165 ° C for 20 minutes. And who has the most excellent tensile strength properties are variable 170 ° C for 20 minutes, while the best of % elongation is at a variable 160 ° C 20 minutes.;In this work, palm fiber crushed and sieved size 40 # after the palm fiber chemically treated with 2% NaOH for 1 hour, 0.1 N KMnO4 for 15 minutes, and 5% NaClO for 5 hours in order to obtain crystalline cellulose. Once that is done the dry mixing (hotmelt mixing) between polypropylene and palm fiber chemical treatment results with 7.5% volume of the palm fiber and polypropylene with a variable temperature of 160°C, 165°C and 170°C and a variable time mixing 15 minutes and 20 minutes. After it was examined FTIR test for fiber, while the composite is made tensile test, STA test, XRD test and FE-SEM test this is done to obtain crystallinity and mechanical properties of polypropylene composites this. The results show that fiber perlakuaan results more crystalline fibers than untreated palm fiber, polypropylene and palm fiber chemistry results treatment compatible enough to polypropylene, crystallinity of the research showed the best properties on the variable 165 ° C for 20 minutes. And who has the most excellent tensile strength properties are variable 170 ° C for 20 minutes, while the best of % elongation is at a variable 160 ° C 20 minutes.;In this work, palm fiber crushed and sieved size 40 # after the palm fiber chemically treated with 2% NaOH for 1 hour, 0.1 N KMnO4 for 15 minutes, and 5% NaClO for 5 hours in order to obtain crystalline cellulose. Once that is done the dry mixing (hotmelt mixing) between polypropylene and palm fiber chemical treatment results with 7.5% volume of the palm fiber and polypropylene with a variable temperature of 160°C, 165°C and 170°C and a variable time mixing 15 minutes and 20 minutes. After it was examined FTIR test for fiber, while the composite is made tensile test, STA test, XRD test and FE-SEM test this is done to obtain crystallinity and mechanical properties of polypropylene composites this. The results show that fiber perlakuaan results more crystalline fibers than untreated palm fiber, polypropylene and palm fiber chemistry results treatment compatible enough to polypropylene, crystallinity of the research showed the best properties on the variable 165 ° C for 20 minutes. And who has the most excellent tensile strength properties are variable 170 ° C for 20 minutes, while the best of % elongation is at a variable 160 ° C 20 minutes.;In this work, palm fiber crushed and sieved size 40 # after the palm fiber chemically treated with 2% NaOH for 1 hour, 0.1 N KMnO4 for 15 minutes, and 5% NaClO for 5 hours in order to obtain crystalline cellulose. Once that is done the dry mixing (hotmelt mixing) between polypropylene and palm fiber chemical treatment results with 7.5% volume of the palm fiber and polypropylene with a variable temperature of 160°C, 165°C and 170°C and a variable time mixing 15 minutes and 20 minutes. After it was examined FTIR test for fiber, while the composite is made tensile test, STA test, XRD test and FE-SEM test this is done to obtain crystallinity and mechanical properties of polypropylene composites this. The results show that fiber perlakuaan results more crystalline fibers than untreated palm fiber, polypropylene and palm fiber chemistry results treatment compatible enough to polypropylene, crystallinity of the research showed the best properties on the variable 165 ° C for 20 minutes. And who has the most excellent tensile strength properties are variable 170 ° C for 20 minutes, while the best of % elongation is at a variable 160 ° C 20 minutes.;In this work, palm fiber crushed and sieved size 40 # after the palm fiber chemically treated with 2% NaOH for 1 hour, 0.1 N KMnO4 for 15 minutes, and 5% NaClO for 5 hours in order to obtain crystalline cellulose. Once that is done the dry mixing (hotmelt mixing) between polypropylene and palm fiber chemical treatment results with 7.5% volume of the palm fiber and polypropylene with a variable temperature of 160°C, 165°C and 170°C and a variable time mixing 15 minutes and 20 minutes. After it was examined FTIR test for fiber, while the composite is made tensile test, STA test, XRD test and FE-SEM test this is done to obtain crystallinity and mechanical properties of polypropylene composites this. The results show that fiber perlakuaan results more crystalline fibers than untreated palm fiber, polypropylene and palm fiber chemistry results treatment compatible enough to polypropylene, crystallinity of the research showed the best properties on the variable 165 ° C for 20 minutes. And who has the most excellent tensile strength properties are variable 170 ° C for 20 minutes, while the best of % elongation is at a variable 160 ° C 20 minutes., In this work, palm fiber crushed and sieved size 40 # after the palm fiber chemically treated with 2% NaOH for 1 hour, 0.1 N KMnO4 for 15 minutes, and 5% NaClO for 5 hours in order to obtain crystalline cellulose. Once that is done the dry mixing (hotmelt mixing) between polypropylene and palm fiber chemical treatment results with 7.5% volume of the palm fiber and polypropylene with a variable temperature of 160°C, 165°C and 170°C and a variable time mixing 15 minutes and 20 minutes. After it was examined FTIR test for fiber, while the composite is made tensile test, STA test, XRD test and FE-SEM test this is done to obtain crystallinity and mechanical properties of polypropylene composites this. The results show that fiber perlakuaan results more crystalline fibers than untreated palm fiber, polypropylene and palm fiber chemistry results treatment compatible enough to polypropylene, crystallinity of the research showed the best properties on the variable 165 ° C for 20 minutes. And who has the most excellent tensile strength properties are variable 170 ° C for 20 minutes, while the best of % elongation is at a variable 160 ° C 20 minutes.]

Abstrak :
This book highlights the origin of low external quantum efficiency for deep ultraviolet light-emitting diodes (DUV LEDs). In addition, it puts forward solutions for increasing the internal quantum efficiency and the light extraction efficiency of DUV LEDs. The book chiefly concentrates on approaches that can be used to improve the crystalline quality, increase carrier injection, reduce the polarization-induced electric field within multiple quantum wells, suppress the TM polarization emission, and enhance the light escape from the semiconductor layer. It also demonstrates insightful device physics for DUV LEDs, which will greatly benefit the optoelectronic community.

Abstrak :
The fourth edition of this class-tested, multi-disciplinary introduction to solid state engineering adds dozens of revised and updated sections and problems, as well as three new chapters on solar energy harvesting, thermal and photothermal energy harvesting, and photo-thermovoltaics. Combining concepts from physics, chemistry, electrical engineering, materials science, and mechanical engineering, Professor Razeghi describes electron-electron and electron-phonon interactions, the Kane effective mass method, the carbon atom, thermal properties of crystals, the harmonic oscillator, the hydrogen atom, the quantum mechanical description of angular momentum, and the origin of spin in a chapter devoted to quantum mechanics. This textbook features an improved transport theory description that goes beyond Drude theory, discussing the Boltzmann approach. Introducing students to the rigorous quantum mechanical way of thinking about and formulating transport processes, this fourth edition presents the basic physics concepts and thorough treatment of semiconductor characterization technology, designed for solid state engineers.