Judul: Studi Efisiensi dan Kinerja dari Sel Surya Multijunction Al0.3Ga0.7As/Inp/Ge terhadap Variasi Suhu
Abstrak: Penggabungan beberapa bahan semikonduktor sel surya untuk memperoleh nilai efisiensi yang tinggi dikenal dengan sel surya multijunction. Salah satu faktor yang dapat memengaruhi kinerja dan efisiensi dari sel surya adalah suhu sel surya itu sendiri. Penelitian ini menggunakan program PC1D sebagai simulator sel surya dan program Matlab untuk melakukan perhitungan intensitas. Bahan semikoduktor yang digunakan adalah Al0.3Ga0.7As, InP dan Ge. Sel surya multijunction Al0.3Ga0.7As/InP/Ge dengan variasi suhu 25, 50, 75 dan 100 ºC menghasilkan tegangan open circuit yang menurun pada setiap lapisan sebanding dengan kenaikan suhu sel surya. Tegangan open circuit pada lapisan pertama Al0.3Ga0.7As menurun sebesar -8.7 mV/ ºC, lapisan kedua InP mengalami penurunan sebesar -1.4 mV/ ºC dan lapisan ketiga Ge mengalami penurunan sebesar -1.3 mV/ ºC. Koefisien suhu dari efisiensi total sel surya multijunction Al0.3Ga0.7As/InP/Ge adalah sebesar -0.34 %/ ºC. Peningkatan suhu sel surya menyebabkan penurunan terhadap kinerja dan efisiensi sel surya multijunction Al0.3Ga0.7As/InP/Ge.
Keyword: efisiensi, sel surya multijunction, spektrum AM1.5G, suhu

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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