Judul: Uji Struktur dan Sifat Listrik Silikon Dioksida dan Silikon dari Sekam Padi
Abstrak: Rice husk charcoal is known to contain 93.67% of silicon dioxide and has the potential to produce silicon. This study produced silicon dioxide and silicon, that had been tested for the electrical and structural properties. Incineration process of rice husk charcoal was performed in a furnace at a temperature of 400 oC for 2 hours and 1000 oC for 1 hour, with the increase rate of 5 oC/minute. The incineration yield then washed with HCl 3% (12 ml HCl 3% for 1 grams of rice husk ash), and heated using hotplate and magnetic stirrer, with a speed of 240 rpm for 2 hours at 200 oC. Furthermore sample washed repeatedly using hot distilled water until free of acid, then reheated in a furnace to produce silicon dioxide. Silicon dioxide produced approximately 5.6 to 6.8 grams of 10 grams of rice husk charcoal. The silicon dioxide then mixed with reductor (magnesium powder), using comparisons based on stoikhiometri, afterwards heated in a furnace for 1 hour with a temperature of 650 oC. Based on the results of XRD analysis, the crystallinity of silicon dioxide reaches 75.85 to 83.28% and silicon with value of 53.34%. XRD analysis showed that the silicon dioxide structure is tetragonal with lattice constants a = 12.45 Å and c = 111.77 Å, while the silicon has cube structural with lattice constants a = 5.27 Å. SEM results showed that the silicon dioxide has the smoother surface and the silicon had formed a crystal structure. EDX results for silicon dioxide of about 77.88 to 81.64% and silicon 42.29%. Analysis of electrical properties was performed using the LCR meter and I-V meter, and was known that the silicon dioxide and silicon have the characteristic of semiconductor, where the electrical conductivity of silicon has a value higher than silicon dioxide. The I-V curves showed that silicon dioxide is a diode, while the diode is a resistor.
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Judul: Penambahan magnesium berlebih dalam menghasilkan silikon murni dari sekam padi sebagai bahan semikonduktor
Abstrak: Rice is one of the most important cultivated plants in human civilization. Rice is also one of the main carbohydrate source the majority of the population in Indonesia. Central Statistics Agency (BPS 2012), estimates that in 2012 rice production reached 68.59 million tons, up by 2.84 million tonnes (4:13%) than in 2011. Seeing this, then it will appear in the form of agricultural waste rice husk. Most of the waste generated from the processing of rice had only burned or thrown away (Azadi et al 2010). Utilization of rice husk furnace developed by IPB since 2007, generating more waste in the form of waste rice husk (Irzaman et al 2007). Rice husk charcoal is known to contain at 95.14% silicon dioxide (Supaman et al 2010) and has the potential to produce pure silicon with a rate 40.78% (Hikmawati 2010) and 42.29% (Ahmad L 2012). This study aimed to examine the characteristics of silicon powder obtained from rice husk by chemical reduction method, which reduces the silicon dioxide using magnesium (Mg) powder to vary the ratio of the amount of silicon dioxide with magnesium and washing with a solution of HCl in the purification. Silicon dioxide and silicon obtained will be analyzed using X-Ray Difraction (XRD), Scanning Electron Microscope-Energy Distersive X-Ray (SEM-EDX), LCR meter and I-V meter. Manufacture of silicon through three (3) phases, husk charcoal, silicon dioxide and silicon. Husk charcoal through several stages. At first the rice husk is dried with the aid of sunlight with the purpose of accelerating the combustion process. Then the rice husks were weighed at 5000 grams (5 kg), entered into a husk furnace and continued with the process of burning, then the rice husk charcoal weighed. In this process produced rice husk for 1440 grams (1.44 kg). Rice husk as much as 40 grams put in porcelain dish and baked in a kiln at a temperature initially 400 °C for 2 hours, subsequent heating to temperatures of 1000 °C for 1 hour with the temperature rising rate setting by 1 °C/minutes and 5 ° C/minutes. After the ash obtained by burning weighed, then washed rice husk ash using hydrochloric acid (HCl) 3% technical which 12 mL of HCl 3% for 1 gram of technical rice husk ash, then heated over a hotplate with temperature settings 200 °C and stirred with magnetic stirrer at a speed of 240 rpm for 2 hours. Subsequently washed with hot distilled water (temperature of about 90-100 °C) repeatedly until acid-free (tested with litmus paper), and then filtered through ash-free paper. Screening results (residue separated from the filter paper) is inserted in the porcelain dish is then heated in a furnace at temperatures of 1000 °C for 1 hour with a temperature rise of 1 °C/minutes and 5 °C/minutes until the silicon dioxide remaining white. The samples were cooled in the furnace and weighed, then the result is tested SEM-EDX, LCR meter and I-V meter (Ahmad L 2012). The next process is to get silicon, silicon dioxide mixed with magnesium powder with a reductant that vary the ratio ranging from ratio
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Judul: Infection Of Babesia Bigemina In Cattle And Methods Of Control
Abstrak: Babesia bigemina is the species which occurs mostly through out the tropics and subtropical areas. It gains access to the susceptible cattle through the bite of an· ig fected tick and penetrates an erythrocyte. The pathogenesis of B. bigemina is considered to be as highly pathogenic and may cause heavy mortality in susceptible stock. Infecied cattle rapidly become dull and listless and lose their appetite, the erythrocytes are destroyed resulting anaemia, icterus, emaciation, weakness, and a drop in milk production. Death and loss of productivity due to B. bigemina account for the economic loss.
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