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: 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: Durability of Specific Immunoglobulin (Ig) Y Againts Influenza and Covid-19 in Sunscreen
Abstrak: The benefit of specific immunoglobulin Y (Ig Y) as an active ingredient in personal care products such as sunscreen has not been properly studied. Our study aims to evaluate the reliability of specific IgY against influenza and the COVID-19 virus in a sample sunscreen product. Specific IgY influenza and COVID-19 viruses were inserted in the sample sunscreen at two concentrations of 0.1% and 0.25%. Three treatments were observed: control (C) sunscreen without IgY, treatment 1 (T1) sunscreen with 0.1% IgY, and treatment 2 (T2) sunscreen with 0.25% IgY. Organoleptic observations were carried out to monitor changes in aroma, color, and texture, and sunscreen sampling was done every week for 6 weeks. The durability of IgY was evaluated using an enzyme-linked immunosorbent assay (ELISA) and a neutralization assay. Organoleptic observation from weeks 1 to 6 showed consistency in its aroma, color, and texture. Enzyme-linked immunosorbent assay and neutralization assay (NA) results of the T1 and T2 groups showed negative results except for sample T1 at week 5, which showed a positive result in the Influenza A ELISA. Based on the results, it seems that IgY concentrations of 0.1% or 0.25% were not optimal. However, this negative result might be due to low concentration of the IgY and the presence of beeswax, which inhibits IgY and causes it to dissolve in distilled water, thus preventing it from being detected in the assay.
Keyword: Immunoglobulin Y, Sunscreen, Influenza, COVID-19, Biological Activity