Hasil Pencarian  ::  Simpan CSV :: Kembali

"Polikristal AgGaSe2 adalah senyawa (I-III-VI2) suatu semikonduktor sebagai bahan dasar pembuatan lapisan tipis (thin film) untuk sel surya. Polikristal tersebut telah berhasil ditumbuhkan dengan metoda tungku Bridgmann tegak, dengan memanaskan sampai temperatut 850°C kemudian didinginkan perlahan-lahan sampai temperatur kamar.Hasil yang didapatkan berupa ingot (batangan) dengan panjang lebih kurang 3 cm dan diameter 13 mm. Dengan menggunakan XRay Refraction didapatkan komposisi masing masing unsur berat % adalah Ag = 29,3996 %, Ga = 36,8123 % dan Se = 30,29 % sedangkan pengukuran dengan X-Ray Difraction didapatkan parameter kisinya dihitung a = 4,4112 Å, c = 8, 8854 Å dan c/a = 2,01426.

---

Optic Properties on AgGaSe2 Polycristal Fabrication. Polycristal AgGaSe2, is compound (I-III-VI2) a semiconductor as basic material for thin film for solar cell. Polycristal was succesfully grown using Bridgmann Method, heated on sequential temperature treatment until 850°C and cooled down slowly until room temperature.Results observed were in the form of ingot (bars) with more or less 3 cm length and 13 mm in diameter. By using X-Ray Fefraction, composition obtained of each element (weight %) was Ag = 29,3996 %, Ga = 36,8123 % and Se = 30,29 % while using X-Ray Difraction lattice parameter obtained/calculated a = 4,4112 Å, c = 8,8854 Å, and c/a = 2,01426."

"This paper presents a methods for estimating permeability of porous media based on lettice gas automata (LGA) methods. LGA is a relatively recent methods developed to perform hydrodynamic calculations. The methods , in its simplest form consists of a regular lattice populated with particles that hop from site to site in discrete time steps in a process, called prppagation. After propagation , the particles in each site interact with each other in a process called collision,in which the number of particles an momentum are conserved. An exclusion principle is imposed in order to achieve better computational efficiency. Permeability estimation of fractured rocks based on image analysis was conducted using lattice gas automata . Fractured rocks samples collected from Bukit Kaba, Bengkulu were analyzed to study fluid flow parameter, i.e. permeability and porosity. For time - ste 1.047 and radius 0,60 cm, the permeability is equal to 2,55.10 Darcy while for time - step 1, 437 and radius 0,19 cm, the permebiality is equal to 1,62.10 Darcy."

"Penelitian ini dilakukan untuk mengetahui seberapa jauh pengaruh pemberian variasi tekanan maupun penambahan unsur lain yakni Cu dan Bi pada karakteristik fasa Sn di dalam material Sn, SnCu dan SnCuBi3. Analisa yang dilakukan berupa tinjauan terhadap perubahan kristalografi dan kerapatan elektronnya. Variasi tekanan yang dilakukan dalam penellitian ini meliputi tekanan 0 ton, 5 ton, 10 ton dan 15 ton. Sedangkan variasi pada penambahan unsur lain selain Sn berupa penambahan Cu pada paduan SnCu dan penambahan Cu-Bi pada paduan SnCuBi3, dimana kedua paduan ini kemudian akan dibandingkan terhadap material Sn mumi.

---

This research is performed to determine the effect of varied pressure and addition of Cu and Bi to the phase characteristic of Sn in Sn, SnCu and SnCuBi3 material. Crystallographic and electron density change were analyzed. Pressure variation of 0, 5, 10 and 15 tons were applied. As for addition of Cu and Bi for SnCu and SnCuBi3 respectively to compare against pristine Sn material were also analyzed."

"Manufaktur aditif, melalui perkembangan dan penyebarannya, telah memungkinkan kebebasan yang lebih besar dalam hal desain komponen dan kemudahan untuk menguji desain tersebut. Elemen umum yang digunakan dalam desain untuk manufaktur aditif adalah mengubah geometri padat menjadi bentuk berongga dengan struktur lattice internal untuk mempertahankan kekakuan dan kekuatan bentuk awal. Studi ini bertujuan untuk mengembangkan sebuah metode optimalisasi struktur lattice pada komponen yang dikenai beban, dengan tujuan meminimalisasi volume material yang digunakan serta stres yang dialami oleh komponen tersebut. FEA digunakan untuk menentukan kepadatan dari lattice pada area tertentu, menambahkan material ke area yang mengalami stres tinggi dan menguranginya pada area yang mengalami stres rendah. Kerangka ini diuji pada batang yang mengalami beban lentur. Perbandingan kemudian dilakukan dengan struktur lattice berbentuk seragam.

---

Additive manufacturing has, through its development and proliferation, allowed for greater degrees of freedom when it comes to the design of components and ease at which to test said designs. A common element used in designing for additive manufacturing is turning a solid geometry into one that is hollow with an internal lattice structure to maintain stiffness and strength. This study aims to develop a method of optimizing the lattice structure of a component under load, aiming to minimize both volume of material used as well as stress experienced by the component. FEA is used to determine the relative density of the lattice at a given area, adding material to areas of high stress and removing it in areas of low stress. This framework is tested on a beam that is experiencing a bending load. A comparison is then made to a lattice structure of uniform shape."

"A numerical model based on the new theoretical micromechanical and lattice models has been proposed to simulate the fracture behavior of concrete specimens....."

"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.

---

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."