Judul: Simulasi Perancangan Sel Surya Multijunction Al0.3Ga0.7As/GaAs/Ge Menggunakan Program PC1D Dan Matlab
Abstrak: Solar cell design is based on the composing of semiconductor layers (multijunction) with energy gap varies in each layer are arranged from highest to lowest can maximize the absorption of solar radiation intensity. Using optimum doping and optimum thickness on semiconductor can maximize the power conversion of the intensity absorbed. Absorbed intensity and amount of electrical power generated at each layer can increase the total efficiency of solar cell. Simulations carried out with 2 models, model 1 which produce different currents and model 2 that produce the same current. Semiconductor layers used is Al0.3Ga0.7As, GaAs, and Ge. Model 1 produces currents Isc at each layer of 26.4 mA, 14.9 mA, and 13 mA and total efficiency of 39.2%. Model 2 produces constant currents of 13 mA and total efficiency of 21.7%. The entire simulations were performed using 0.1367 W/cm2 of solar intensity that obtained from calculation of black body radiation spectrum of the sun's surface at 6000K
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Judul: Simulasi Kinerja Sel Surya 4-Junction Al0.3Ga0.7As/GaAs/InP/Ge dengan Pembatasan Daerah Serapan Radiasi Matahari.
Abstrak: Solar cells development increased rapidly indicated by the increasing solar cells efficiency. One way to increase the efficiency is by using multi-junction solar cells. In this research, 4-junction solar cells Al0.3Ga0.7As/GaAs/InP/Ge has been designed and simulated using PC1Dv5.9 program in two different models. In Model 1, different current is produced in each sublayer, while in Model 2 the identical current restricted in each sublayer. Every models are simulated in two different conditions, i.e without absorption area restriction (wavelength fron 280 to 2500 nm) and with restriction of solar radiation (restricted cutoff wavelength). Model 1 showed that solar cells without spectrum restriction (efficiency 64.23%) are more efficient than the one with restriction (efficiency 36.48%). Model 2 showed smaller efficiency compared to Model 1, with 12.75 % efficiency for solar cells without spectrum restriction and 2.81% for the one with restriction. All simulations were performed using AM1.5G radiation spectrum.
Keyword: solar cells, PC1D program, multi-junction, efficiency

Judul: Posisi Filogenetik Kura-Kura Carettochelys Insculpta  (Reptillia: Testudinata)
Abstrak: Carettochelys insculpta is an endemic freshwater turtle of southern Papua and northern Australia. Phylogenetic position of this turtle is remain unresolved until now. Most of the research conducted show close relationships of C. insculpta and members of Trionychidae family. However, some of the research show distance between C. insculpta and members of Trionychidae family. This research is conducted to analyze phylogenetic relationship between C. insculpta and other members of Testudinata using 12S rRNA, 16S rRNA, and both gene as markers. DNA samples were obtained from three different organisms of C. insculpta. Two species used as outgroups were Alligator mississippiensis and Iguana iguana. Phylogenetic analysis was carried out using Neighbor-Joining method with Felsenstein 1981 (F81) modeltest. A polytomy tree of Testudinata was produced by using 12S rRNA gene. However, analysis using 16S rRNA and both genes as markers confirmed that C. insculpta was located between the Chelonidae and the Trionychidae family.
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