Judul: Pemurnian Silikon Asal Arang Sekam Padi Menggunakan Magnesium dan Gas Nitrogen
Abstrak: Rice husk charcoal is an agricultural waste containing 72% silica that is a potential alternative source of silicon. Silicon from silica derived from the husk was purified by reduction using magnesium and subsequently washing with HCl 3%. Oxygen in air is suspected to react with the magnesium during the reduction process, such that the silica form was still present in the reduction product. The objective of this research is to compare the purity of silicon obtained from silica reduction using magnesium under nitrogen gas flow and under ambient air flow. The nitrogen gas was used to avoid oxygen from reacting so the magnesium only reacted with the silica. The silicon was characterized using X-Ray Diffraction and data were analyzed using Match 2 software. The yield of silicon from the reduction process without nitrogen gas flow was 59%. This is smaller than the 64% silicon yield obtained from the reduction process using nitrogen gas flow. Application of nitrogen gas flow to the silica reduction process with magnesium increases the silicon yield and affecyed the silicon purity.
Keyword: Bogor Agricultural University (IPB), silicon, silica reduction, rice husk, nitrogen gas

Judul: Optimalisasi pemurnian silikon berbahan dasar arang sekam padi menggunakan reaktor tertutup
Abstrak: High silica (SiO2) concentration in charcoal rice husk could be used as silicon with 40-60% level of purity. Low purity is caused by the effect of oxygen involved in the reduction process. The aim of this research was to optimize reduction process of silica from charcoal rice husk to obtain silicon with high purity level. The optimization process of silica reduction was conducted in closed reactor using alumina and stainless steel tube with magnesium as reducing agent in mass ratio of SiO2 and Mg 1:1 and 1:2. The reduction products were leached by HCl 10% at the first step, and a mixture of 2M HCl and CH3COOH 25% at the second step. Silicon products were characterized by X-ray diffraction (XRD) and MATCH 2 program. In mass ratio of SiO2 and Mg 1:1, quantitative value of XRD (QXRD) silicon in alumina tube reactor (22%) was higher than that in the stainless steel tube reactor (16%). In alumina tube reactor, QXRD silicon in mass ratio of SiO2 and Mg 1:1 that value was lower than that of 1:2 (50%). The acid leaching process removed major impurities, such as MgO, Mg2SiO4, and SiO2. The highest purity of silicon was produced from alumina tube reactor with mass ratio of SiO2 and Mg 1:2.
Keyword: Bogor Agricultural University, silicon, silica, closed reactor, charcoal rice husk

Judul: Pengaruh Infeksi Haemoproteus columbae (Kruse, 1890) Pada Burung Merpati Dan Cara Penanggulangannya
Abstrak: Haemoproteus columbae merupakan paras it yang menyerang sel-sel darah merah burung rnerpati. Siklus hidupnya kompleks dan dapat dibagi menjadi dua yaitu siklus hidup asexual terjadi delam tubuh burung merpati dan siklus hidup sexual terjadi dalam tubuh lalat dari famili Hippoboscidae sebagai vektor. Stadium yang nampak dalam peredaran darah perifer hanyalah garoetosit yang dapat dibedakan menjadi dua yaitu gametosit jantan (mikrogametosit) dan gametosit betina (makrogametosit).
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