Hasil Pencarian  ::  Simpan CSV :: Kembali

Abstrak :
ABSTRAK
Pcnggunaan zcolit alam di Indonesia scbagai bahan baku mcmiliki potcnsi bcsar untuk dikcmbangkan dalam dunia industri maupun perta.nian.Dimana, zeolit di alam terdapat di sekilar gunung berapi.Jcnis zeolil aiam sangai dipengnruhi oleh lingklmgan lokal scpcni lcmpcralur, tckanan uap air dan komposisi air tanah lokasi.Sehingga zeolil nlam pads umumnya hcnnutu rcndah.

Pada pcnclilian ini, zeolit yang memiliki bentuk pori tetrahedral dan kandungan unsur Si dan Al scbagai umsur dominan.S<:rbuk zeolit di rej7uk.s(cuci) pada tcrnpcratur 200°C lalu dikcringkan pada tcmperalur ll0°C sclama 3 jam.Kemudian dikompaksi dcngan tukanan 45.000 N.K.cmudian disinlcr padda tcmpcratur BUOUC dcngan wakhl sinlcr 60 menil, 70 mcnii dan 80 mcnil.

Hasil pcnclilian mcnunjukan zeoil lampung mcmiiiki komposisi rasio rata-rata Si/Al 5,485 dan rnemiliki profil zcolit dominan jenis klinoptilolil dengan fraksi bcrat sebesa: 83,34 % sedang jenis mordcnit sebesar l5,66%.80 menit 46_67%.Pcngaruh waktu sinler terhadap kekerasan (VI-TN) zcolit pada 60 meniI.,70 dau 80 menil bertumt- turut adalah 125,320 kg/mmz; 130,518 kg,/mm? dan 133,417 kg/mmz.

---

Abstrak :
3D sound is a new trend in various media, such as movies, video games, and musicals. Interpolated head-related transfer functions (HRTFs) are a key factor in its production, due to real-time system limitations in storing measured HRTFs. In addition, the interpolation of HRTFs can reduce the need to measure a large amount of HRTFs and the associated effort. In this research, we used the PKU-IOA HRTF Database and covered three interpolation techniques, namely bilinear rectangular, bilinear triangular, and tetrahedral. Bilinear interpolations can be used to compute weights in interpolating measured HRTFs in a linear fashion, with respect to azimuth and elevation angles. Such interpolations have been proposed for three measurement points that form a triangle or for four measurement points that form a rectangle, surrounding the HRTF at a desired point. These geometrical approaches compute weights from a distance of the desired point from each measurement point. Tetrahedral interpolation, meanwhile, is a technique for HRTF measurements in 3D (i.e. azimuth, elevation, and distance) using barycentric weights. Based on our experiments, 3D tetrahedral interpolation results in the best average mean square error (MSE) of 3.72% for minimum phase head related impulse responses (HRIRs) and best average spectral distortion (SD) of 2.79 dB for magnitude HRTFs, compared to 2D bilinear interpolations (i.e. rectangular and triangular interpolation). Regarding the latter, bilinear rectangular interpolation generally performs better than the triangular variety. Additionally, the use of minimum phase HRIRs as input data results in more optimal interpolated data than magnitude HRTFs. We therefore propose an optimal framework for obtaining estimated HRIRs by interpolating minimum phase HRIRs using tetrahedral interpolation. Such HRIRs have been simulated to produce virtual 3D moving sound in a horizontal plane with a difference of 2.5o of azimuth angle. The simulated moving sound that is heard moves naturally in a clockwise direction from an azimuth angle of 0o to 360o.

Abstrak :
3D sound is a new trend in various media, such as movies, video games, and musicals. Interpolated head-related transfer functions (HRTFs) are a key factor in its production, due to real-time system limitations in storing measured HRTFs. In addition, the interpolation of HRTFs can reduce the need to measure a large amount of HRTFs and the associated effort. In this research, we used the PKU-IOA HRTF Database and covered three interpolation techniques, namely bilinear rectangular, bilinear triangular, and tetrahedral. Bilinear interpolations can be used to compute weights in interpolating measured HRTFs in a linear fashion, with respect to azimuth and elevation angles. Such interpolations have been proposed for three measurement points that form a triangle or for four measurement points that form a rectangle, surrounding the HRTF at a desired point. These geometrical approaches compute weights from a distance of the desired point from each measurement point. Tetrahedral interpolation, meanwhile, is a technique for HRTF measurements in 3D (i.e. azimuth, elevation, and distance) using barycentric weights. Based on our experiments, 3D tetrahedral interpolation results in the best average mean square error (MSE) of 3.72% for minimum phase head related impulse responses (HRIRs) and best average spectral distortion (SD) of 2.79 dB for magnitude HRTFs, compared to 2D bilinear interpolations (i.e. rectangular and triangular interpolation). Regarding the latter, bilinear rectangular interpolation generally performs better than the triangular variety. Additionally, the use of minimum phase HRIRs as input data results in more optimal interpolated data than magnitude HRTFs. We therefore propose an optimal framework for obtaining estimated HRIRs by interpolating minimum phase HRIRs using tetrahedral interpolation. Such HRIRs have been simulated to produce virtual 3D moving sound in a horizontal plane with a difference of 2.5o of azimuth angle. The simulated moving sound that is heard moves naturally in a clockwise direction from an azimuth angle of 0o to 360o.

Abstrak :
Densitas keadaan elektron a-Si_1-xC_x, and a-Si_1-xH_y telah dihitung untuk seluruh konsentrasi karbon dan beberapa konsentrasi hidrogen (0≤y≤0.5). Struktur atom dimodelkan dengan struktur acak kontinu yang menghubungkan atom Si, C dan H. Keadaan elektron diperoleh dengan menyelesaikan Hamiltonian tight binding kisi Bethe dengan pendekatan medan efektif. Metode Gomez-Santos dan Verges digunakan untuk memperoleh perata-rataan DOS yang memperhitungkan ketidakteraturan diagonal dan off diagonal serta ketidakteraturan parameter SRO (short range order). Model struktur yang digunakan berdasarkan konfigurasi tetrahedral dari atom Si dan C serta konfigurasi trigonal dari atom C. Kehadiran hidrogen menyebabkan pergeseran ujung atas pita valensi ke energi yang lebih rendah sehingga mengakibatkan pelebaran gap pada a-Si_1-xH_y, a-C_1-yH_y(C-sp³) dan a-C_1-yH_y (C-sp²). Pergeseran ujung atas pita valensi ke energi yang lebih rendah juga terjadi dengan kenaikan konsentrasi karbon pada a-Si_1-x, Cx(C-sp³). Pergeseran ujung atas pita valensi yang berbeda terjadi pada a-Si_1-x Cx (C-sp²) yang bergeser ke energi yang lebih tinggi. Selain itu ujung bawah pita konduksi juga bergeser ke energi yang lebih tinggi. Kenaikan lebar gap yang lebih tinggi terjadi untuk konfigurasi karbon berikatan tetrahedral sp³ dibandingkan konfigurasi karbon berikatan trigonal sp2. Kehadiran hydrogen dan karbon secara bersamaan pada aSi_1-xC_x:H_y(C-sp³) dan a-Si C_1-xC_x (C-sp²) meningkatkan lebar gap. Peningkatan fraksi karbon dalam bentuk grafit meningkatkan lebar gap a-Si_1-x C_x (C-sp² dan C-sp³) sampai konsentrasi karbon x=0.6.