Judul: Design and Working Performance of Sugar Cane Stubble Shaver Powered by Four Wheel Tractor
Abstrak: Cutting of sugar cane stubbles is an important activity in ratoon sugar cane production system. Stubble shaver powered by four wheel tractor, has been used in several sugar plantation in Indonesia. However, there were some problems encountered the application such as high power consumption; excessive blade tip wear; and low cutting quality of the stalks. The objectives of this research were: 1) to design a stubble shaver powered by PTO of four wheel tractor and 2) to analyze the influences of blade tip design, forward speed, rotation speed and tilt angle of the rotary cutting unit on cutting power and cutting quality. A sugar cane stubble shaver consisting of a rotary cutting unit with 8 blades rotated by tractor PTO, was designed and constructed. The prototype was tested to measure its working performance. The test was conducted using two types of blade tip design, on two levels of working speed (0.3 and 0.5 m s-1), two levels of rotational speed (500 and 850 rpm), and two levels of blade tilt angle (45o and 60o). The test result showed that the blade tip design with increased tip radius provided a lower working torque than the conventional blade tip design with constant tip radius. The lowest working torque was provided by operating condition of working speed of 0.5 m s-1, blade rotating speed of 850 rpm and tilt angle of 60o. The average working torque on that condition was 22.46 Nm. However, 0.3 m s-1 working speed, at 850 rpm rotating speed and 45o tilt angle provided a better stubble cutting quality than the other working condition.
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Judul: Modifikasi dan uji kinerja mesin kepras tebu tipe pisau rotari untuk traktor roda empat
Abstrak: Ratton cultivation needs stubble shaving operation after harvest. Sugar cane ratoon cultivation is common practices to reduce production cost of sugar. Now stubble shaving operation is done manually using hoe which low in capacity and high in cost. An efficient machine is needed to reduce the cost of stubble shaving. This research was aimed to modify, fabricate, and test the prototype of sugar cane stubbke shave that was aatached to a four wheel tractor an rotated by PTO of the tracttor. Two transmission systems of rotary knife-cutter were speed which are flexible shaft and double universal joint. Test parameter in this research were speed rotational, inclination of cutting, and posotion of cutting. The serult showed that the prototype worked better with double universal joint transmission system. In this research, flexible shaft system did not work well because the required cutting torque ws higher than the shear resistance of the flexible shaft. Result of the test showed that stubble shaving of sugar cane with rotary knife-cutter had a better performance in 780 rpm and ^0 beta of cutting inclination. Average torque was 41.98 Nm with average deep about 13 cm. In addition average working width of the cutter was 37 cm.
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Judul: Psittacosis Sebagai Zoonosis Penting Yang Berasal Dari Burung
Abstrak: Psittacosis atau ornithosis adalah penyakit menular dari burung kepada manusia. Agens penyebab psittacosis termasuk ke dalam virus psittacosis-lymphogranuloma venereum group yang disebut Chlamydia psittaci. C. psittaci hanya dapat berkembang biak di dalam jaringan hidup tetapi peka terhadap antibiotik. Penyebaran penyakit ini sangat luas, terdapat hampir di seluruh dunia. Di Indonesia penyakit ini belum pernah di diagnosa, tetapi mengingat terdapat demikian banyaknya jenis burung maka diperkirakan psittacosis ini sudah ada. Kasus pada manusia pertamakali ditemukan oleh Ritter pada tahun 1879, di Eropa. Waktu itu dikenal sebagai pneumotyphus. Chlamydia psittaci tidak hanya sebagai penyebab infeksi pada burung, juga bisa menyebabkan infeksi pada mamalia diantaranya sapi, kerbau, kambing, domba, babi dan kucing. Pada kucing dikenal sebagai feline pneumonitis. Pada domba atau kambing mengakibatkan enzootic abortion. Pada burung, kalkun merupakan unggas paling rentan diikuti oleh burung psittacine dan burung lain di luar famili psittacidae. Virulensinyapun berbeda-beda. Yang berasal dari kalkun bervirulensi tinggi, sedangkan yang berasal dari burung merpati bisa bervirulensi tinggi bisa juga bervirulensi rendah. Penularan terjadi melalui kontak langsung maupun ti- dak langsung. Penularan melalui telur tidak terjadi. Umumnya penyakit ini memperlihatkan gejala klinis berupa deman, lesu, lemah, anorexia, kurus, diarrhea ber- warna kekuningan, discharge dari mata dan hidung, conjunc- tivitis. Gejala khas pada kalkun adalah istirahat dengan sternum sebagai dasarnya, karena adanya tekanan dari bagian perut yang sakit. Sedangkan pada manusia memperlihatkan adanya demam, kadang-kadang merasa dingin, lesu, sakit kepala yang hebat, sakit pada bagian belakang badan dan photophobia…dst
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