Judul: Rancangan Pendirian dan Analisis Kelayakan Usaha Produksi Alat Pemerahan Susu Sapi SOTE (Semi Otomatis Tipe Engkol)
Abstrak: Cow milk is the product of dairy cows that is needed by the people of Indonesia in order to meet their nutritional needs. Currently the world's milk production has reached about 385 000 million m3/year, while the national dairy industry of Indonesia in 1999 produced only ± 20% of total milk processing industry needs, so the rest still rely heavily on imported raw materials. Based on this condition it is important to increase the amount of cow milk production, by improving the efficiency and effectiveness of milk dairy using automatic milking machine. Due to the high price of milking machine, which is more than Rp 27 million, cow breeders do not want to buy. Therefore we need semi automatic milking machine. To solve these problems a semi automatic milking machine has been designed. The tool is called a dairy cow milking machine SOTE (Semi Automatic Type Crank). Because cow milking machine SOTE has never been produced specially workshop that produce this milking machine is required. The purpose of this research is to design a business of milking machine production SOTE and to analyze its feasibility level based on market aspects, technical aspects, institutional aspects / management and financial aspects. The size (area) of the workshop is determined by the needs of area for production and material flow from raw material to finished products. The layout of the room, equipment and machinery are arranged in such a way as to form the flow of production so that all rooms can be used efficiently. Analysis shows the workshop is financially feasible, indicated by three investment feasibility criteria: NPV, IRR, and the Net B/C. At the level of 10 % profit selling price (Rp Rp 7 159 348 per unit), the NPV value is Rp 371 883 233, net B/C 12.1 while the IRR value is 286.977 %. The sensitivity analysis shows that this business still feasible on labor cost increases of 5 %, raw material cost increases of 5 %, and both costs increase of 5 %.
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Judul: Rancang Bangun Alat Pemerah Susu Sapi Otomatis dengan Pulsator Tipe Pegas
Abstrak: Milk is an important commodity for improving people nutrition. The main source of milk production is dairy cow. In Indonesia, milk production is dominated by local dairy herdsmen who are still applying milking manually by hand. Actually local dairy herdsmen can use milking machine which is built simple and appropriate with common components. This study aims at design and build automatic milking machine with spring type pulsator. This milking machine can be used by smallscale dairy herdsmen because it is easy to use and maintaince. By using this milking machine, milk is also expexted to be more hygienic. The main components to make up this milking machine are teat cups, spring type pulsator, DC Motor, AC-DC regulator, vacuum pump, milkcan, and frame. The specific distinction of this milking machine with the modern milking machine is no need a claw to connect 4 milk tubes on teat cups with 4 pulse tubes on pulsator. Claw’s function is not replaced by any component, but the milkcan itself is made as direct vacuum reservoir. Power source to run this milking machine is entirely using electricity. Vacuum pump requires 250 watt power to produce vacuum pressure up to 50 kPa at milkcan as vacuum reservoir. And DC motor requires DC voltage at 3-12 V with current 5A to drive the pulsator. Spring type pulsator can produce pulsation rate 60 cycle per minute with pulse ratio 2.5:1, which means the resting phase on teat cups is 2.5 times longer than massage phase. Testing result revealed that the performance of the machine has not produced milk as expexted. Vacuum flow rate which is produced by pump is less efficient if it works at very short time interval. While the resting phase, the pulsation chamber has just begun to connect with vacuum and the interval 5/7 second is too short to produce enough vacuum in order to open the teat cup liners. It is because the vacuum flow rate is nullified at a moment before, while the massage phase running.
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Judul: Kruskal Coordinates in 4+1 Dimensional Schwarzschild  Spacetime Geometry
Abstrak: Koordinat Kruskal adalah hasil ekstensi maksimal dari koordinatSchwarzschild yang menimbulkan interpretasi baru tentang keberadaan wormhole. Secara teori, wormhole adalah struktur yang menghubungkan dua titik berbeda dalam ruangwaktu. Namun, ukuran wormhole terlalu kecil untuk dapat dilalui dan tidak stabil sehingga mudah runtuh. Penelitian ini bertujuan mendapatkan solusi koordinat Kruskal untuk geometri Scwarzschild pada dimensi yang lebih tinggi yang dapat berguna untuk menganalisis kestabilan wormhole. Penelitian ini dilakukan melalui penambahan dimensi ruang dari 3+1 dimensi menjadi 4+1 dimensi untuk mendapatkan geometri Schwarzschild, koordinat Eddington-Finkelstein, dan koordinat Kruskal dengan memanfaatkan gerak radial foton. Hasil akhirnya, solusi geometri ruangwaktu Schwarzschild dalam koordinat Kruskal dapat dibentuk dan diilustrasikan dalam diagram Kruskal. Diagram tersebut menunjukan sebuah black hole, white hole, dan dua alam semesta yang dihubungkan oleh wormhole., The Kruskal coordinates are the maximal extension of the Schwarzschild coordinates which give rise to new interpretations of the existence of wormholes. In theory, a wormhole is a structure that connects two different points in spacetime. However, the size of the wormhole is too small to pass through and is unstable so that it collapses easily. This study aims to obtain Kruskal coordinate solutions for the Scwarzschild geometry in higher dimensions which can be useful for analyzing wormhole stability. This research was carried out by adding space from 3+1 dimensions to 4+1 dimensions to obtain Schwarzschild geometry, Eddington Finkelstein coordinates, and Kruskal coordinates by utilizing the radial motion of photons. The final result, the solution of the Schwarzschild spacetime geometry in Kruskal coordinates can be formed and illustrated in a Kruskal diagram. The diagram shows a black hole, a white hole, and the two universes connected by a wormhole.
Keyword: Schwarzschild geometry, Eddington-Finkelstein coordinates, Kruskal coordinates, radial motion of photons, wormhole