Judul: Analisis Kebutuhan Torsi dan Desain Penjatah Pupuk Butiran Tipe Edge-cell untuk Mesin Pemupuk Jagung
Abstrak: A prototype of integrated machine for planting, fertilizer applicator, and soil tillage for corn cultivation has been developed in 2009. It still had many lacks such as non-uniform seed spacing, unadjusted fertilizer discharge, the level of jamming in driving wheel was 38%, quite high to cause metering device stopped working. Afer being modified, planting and fertilizing performance showed improvement. However, the level of jamming was still high at about 31% which caused inappropriate seed and fertilizer discharge. Due to the excessive friction and fertilizer clogging, the metering rotor often stopped working. Therefore, an optimum design of metering device is needed to overcome the problems. The objectives of the research were: 1) to analyze torque requirement of edge-cell type metering device and 2) to design an edge-cell type metering device for corn fertilizer applicator with lower torque requirement and high accuracy. Metering device used in this research was an edge-cell type rotor, optimally designed to minimize the friction between fertilizer and the rotor tips, produce uniform seed spacing, and require lower torque. The rotor diameter is 40 mm with 6 grooves, its diameter is 4.5 mm each, and rotor length is 80 mm. It was equipped with rotor casing for discharge controlling. For performance test, the hopper and a variable speed electric motor were attached to the metering device in a set of experiments in the laboratory. The rotor shaft was equipped with strain gage to measure the torque requirement. The tests included: accuracy test, uniformity test, torque requirement analysis, and model validation of metering device. The fertilizers used in the research were urea, TSP, and a mixture of TSP and KCl. The rotor rotation speed was varied: 15, 25, and 35 RPM, and fertilizer volume was: 25, 50, and 100%. For comparison, a conventional (prototype-2) metering device was also tested. For torque requirement analysis, a mathematical model to estimate torque requirement of prototype-2 and edge-cell type (prototype-3) metering device was developed. The accuracy test of prototype-3 metering device showed satisfying results. For test on urea, at 50, 75, and 100% rotor opening, the average fertilizer discharge rate was 20.76 g/rotation, 26.00 g/rotation, and 33.56 g/rotation, respectively. It was slightly smaller than teoritical discharge rate. The rotor rotational speed at 15, 25, and 35 RPM gave no significant effect to discharge rate. For test on TSP, at 50, 75, and 100% rotor opening, the average fertilizer discharge rate was 39.81 g/rotation, 50.92 g/rotation, and 62.72 g/rotation, respectively. For test on TSP-KCl mixture, at 50, 75, and 100% rotor opening, the average fertilizer discharge rate was 32.82 g/rotation, 45.83 g/rotation, and 54.58 g/rotation, respectively. The uniformity test also performed satisfying results and the change of fertilizer volume did not affect the discharge rate. For test on urea, at 25, 50, and 100% fertilizer volume, the discharge rate was 33.36 g/rotation, 33.90 g/rotation, and 33.56 g/rotation, respectively. For test on TSP, at 25, 50, and 100% fertilizer volume, the discharge rate was 60.96 g/rotation, 61.03 g/rotation, and 62.72 g/rotation, respectively. For test on TSP-KCl mixture, at 25, 50, and 100% fertilizer volume, the discharge rate
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Judul: Disain dan pengujian metering device untuk unit pemupuk butiran laju variabel (variable rate granular fertilizer applicator)
Abstrak: Uniform rate of fertilizer applicator (URA) practice is disregarding the productive potential of the various areas within the field. Thus, some area is less fertilized and other is over fertilized. It is also an important issue recently that nitrogen from fertilizers may be subjected to lost into atmosphere or enters streams through surface or subsurface drainage (leaching). The place with overfertilization will be a potential source of pollution in the form of ammonia (NH3), nitrite (NO2) and nitrate (NO3) which may hazard people health. Therefore, a contemporary issue is how to give an effective dose at the accurate position and right time for optimum growth of crops while preserving the environment without causing economic losses. Variable rate of fertilizer applicator (VRA) is a solution to overcome the negative impact of URA. It can control the appropriate of fertilizer dosage and location of application in the field. The objective of this research is to design a metering device for variable rate granular fertilizer applicator. In this research, the metering device was equipped with two rotor, which could be operated as single rotor or double rotor. The dose of granular fertilizer could be controlled by the rotation of the rotor. The rotation of the rotor was controlled using digital PID algorithm. The result of variable rate fertilizer testing of the metering device using single rotor indicated that the rate of urea, SP- 36 and NPK are 0.84, 0.96 and 1.2 g/rotation respectively. The testing using double rotor indicated that the rate of urea, SP-36 and NPK are 1.14, 2.22 and 2.1 g/rotation respectively. All results showed that the prototype of metering device can control fertilizer dose of urea, SP-36 and NPK fertilizer precisely.
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Judul: Infeksi Virus Parainfluenza Pada Anjing
Abstrak: Virus parainfluenza anjing termasuk famili Paramyxoviridae, berbentuk pleomorf dengan ukuran bervariasi (bergaris tengah antara 100-500 nm), berpembungkus peka ether, berisi genom RNA dan secara serologis mempunyai kesamaan dengan virus SV-5 kera; dikenak sebagai salah satu kausa penting dari sindrom "kennel cough". Infeksinya dapat mengenai anjing semua umur yang belum pernah terinfeksi atau mendapatkan vaksinasi mengakibatkan gejala klinis ringan yang terbatas pada traktus respirasi atu infeksi yang secara klinis tidak memperlihatkan gejala nyata. Gejala klinis yang nampak setelah masa inkubasi (1-5 hari) terlewati berupa batuk yang tidak berat selama beberapa hari, berbagai tingkat tonsilitis dan pharyngitis dan kadang-kadang ditemukan kenaikan temperatur rektal antara 1-2 derajat C dari temperatur normal rat-rata. Anjing terinfeksi mengandung virus pada traktus respirasi bagian atas dan bawah serta limfonoduli sampai hari ke 9 setelah infeksi. Penyebaran virus antar anjing terjadi secara aerogen.
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