Judul: Interaksi putaran dan jarak konkaf drum mesin perontok TH-6 V. S. oryza serta kadar air biji dan pengaruhnya terhadap mutu dan kapasitas perontokan kedelai
Abstrak: Tujuan penelitian ini ialah menentukan hubungan antara putaran drum (rpm) dan jarak silinder konkaf dengan kadar air, mutu, dan kapasitas perontokan kedelai pada mesin perontok TH-6 V.S Oriza (buatan lokal). K.a kedelai yang dipakai 17 %, 20%, 23 %, dan 26 %, dengan variasi kecepatan putar drum : 400 rpm, 450 rpm, 500 rpm, 550 rpm, dan 600 rpm, dan 4 macam jarak konkaf 15 mm, 25 mm, 35 mm, dan 45 mm. Jarak silinder konkaf yang disarankan adalah 15 mm untuk k.a kedelai 17 % dengan kecepatan putar drum 550 s/d 600 rpm, proses perontokan akan menghasilkan 400 s/d 440 kg/jam dengan susut tercecer 1,21 % s/d 1,43 % dan susut mutu antara 3,17 % s/d 3,8 %. ..dst
Keyword: Forage legumes, Glycine max soyabeans, Soyabean huller

Judul: Kinerja dan Keekonomian Mesin Perontok untuk Kedelai (Studi kasus : Kecamatan Majalengka, Kabupaten Majalengka).
Abstrak: Threshing is one of the important postharvest handling of soybean, where the use of proper threshing machine would be able to reduce the quantity losses and quality losses due to mechanical damage to the threshing process. Mechanical damage arising from the motion mechanism such as motion of stripping, hammering, and impact. Motion mechanism is very dependent on the drum cylinder speed threshing used. Therefore, this study aims to assess the performance threshing machine and analyze the magnitude of losses arising from threshing activities and to analyze the economic in operational of the threshers. This research was conducted in the Sindang Kasih village, Majalengka district with raw materials of Argomulyo soybean varieties. Threshing was done by using two multipurpose threshers, namely thresher A and thresher B as a test group with two treatments that was drum cylinder speed threshing of 515-570 rpm and 580-650 rpm. Observations were done at quantity and quality losses (split seeds, damaged seeds, and dirt). Quantity losses resulting from threshing activities were used to analyze the economics and feasibility of threshers. Economic analysis was done by determining the fixed costs, variable costs, BEP, cost of product and benefits of the threshing process, where feasibility of business was done based on of NPV, IRR, net B/C and payback period . The used thresher on a drum cylinder speed of 580-650 rpm produces the highest quantity and quality losses compared with 515-570 rpm of the both threshers operated. The highest quantity losses on a thresher A was 3.33 %, split seeds was 2.9 % and damaged seeds was 2.57 %, while the quantity losses on a thresher B was 0.72 %, 0.89 % of split seeds and damage seeds was 1.43 % on the thresher operated with drum cylinder speed of 580-650 rpm. The high losses produced at drum cylinder speed 580-650 rpm, therefore the operation of thresher should be done at 515-570 rpm of drum cylinder speed. From the economic analysis, the two threshing machine, was reached a feasibleoperational level with cost of product was Rp. 327/kg-Rp. 369/kg and BEP 15.7-19.2 ha equivalent to 23 562-28 852 kg seeds/year . This effort deserves to be developed with a range of NPV Rp. 1 997 037-Rp. 6523 947, 19.63-32.42 % IRR and a net B/C 1.11-1.43 in the applicable equipment rent wasRp. 400 / kg .
Keyword: Economic, soybean, threshing, quantity losses, quality losses

Judul: Metrik Einstein (Anti-) Self-Dual Berdimensi Empat dengan Metode Cartan
Abstrak: Gravitational field equation can be formulated in differential forms (differential geometry), which describes gravity as a manifestation of the curvature of space-time. Curvature of space-time is characterized by a metric that satisfies the gravitational field equation. With differential forms it can be formulated the (anti-) self-dual Einstein equation, which is a modification of the Cartan structure in (anti-) self-dual basis. Calculation of (anti-) self-dual metric with (anti-) self-dual Einstein equation is simpler than the calculation using Christoffel symbols.
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