Judul: Deteksi Visual dan Analisis Luas Kontak Roda Traksi pada Beberapa Kondisi Permukaan
Abstrak: The intensive application of tractors had an impact to the soil condition of farm through all the forces applied to the soil. Those forces applied through the traction elements which contact to soil. The portion of the wheel or tire in contact with the supporting surface referred to the term of contact area. The measurement of tire contact area is needed due to its effect on tractor performance. The objectives of this research were to study the tire contact area on asphalt road and soil surface also its relation with the sinkage; to compare tire contact area based on the actual measurement with the theoretical tire contact area; to study the lug angle resulted between asphalt road and soil. The biggest average contact area on soil with 47.69% water content was 364.40 cm2, while the smallest was on the asphalt with 121.77 cm2. The biggest average lug angle on soil with 47.69% water content was 37.25°, while the smallest was on the asphalt that is 25.52°. The value of tire contact area in the soil was directly proportional with the soil moisture content and sinkage.
Keyword: asphalt., soil, sinkage, lug angle, tire contact area

Judul: Prediksi Kedalaman Ketenggelaman Roda Traktor Roda-4 pada Tanah Sawah Berdasarkan Hasil Uji Geser Langsung
Abstrak: Paddy soil tillage in Indonesia is still employed by human power, animal power, and hand tractor which requires more time so that resulting low capacity, whereas the use of four-wheel tractor is relatively little. In application, agricultural mechanization causes reciprocal relationship between soil and tractor. Reqiurements in the application of four-wheel tractors on soil tillage are such the ground pressure must be smaller than soil shear strength and sinkage must be smaller than ground clearance of tractor. In this research, estimation of sinkage determined based on direct shear test on undisturbed soil and disturbed soil. The results shows that increasing water content results in declining soil cohesion and soil shear strength. It leads to bigger sinkage. Analysis of using undisturbed soil produces smallest sinkage in SS location dominated by clay fraction with 0.33- 5.49 cm on soil cohesion 0.282-0.397 kgf/cm2 andbiggest sinkage is in S-14 location dominated by the silt fraction with higger than tractor ground clearance (35.5 cm) and soil cohesion 0.011-0.029 kgf/cm2. Based on the predicted results, four-wheel tractor can only operate in location SS and L-18.
Keyword: direct shear test, paddy soil, four-wheel tractor, Sinkage

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
Keyword: