Judul: Management of Sugarcane (Saccharum officinarum L.) in Working Area of Madukismo Sugar Factory, Yogyakarta with Main Aspect of Productivity and Yield of Various Seed Sources
Abstrak: Produksi gula nasional belum cukup untuk memenuhi kebutuhan, sehingga kekurangannya harus dipenuhi melalui impor. Salah satu kegiatan budidaya tebu yang berpengaruh terhadap hasil gula adalah pada penyediaan dan penggunaan benih. Kegiatan magang bertujuan menganalisa perbedaan produktivitas dan rendemen tebu dari beberapa sumber benih di wilayah kerja PG Madukismo, Yogyakarta. Data primer diambil dengan melakukan pengamatan berupa taksasi produksi, pengukuran brix, dan wawancara petani. Hasil menunjukkan bahwa tidak terdapat perbedaan nyata. Produktivitas dari kebun yang benihnya berasal dari PG, petani penangkar, petani non penangkar, dan sumber tidak diketahui berturut-turut adalah 75,73 ton ha-1, 66,88 ton ha-1, 63,29 ton ha-1, dan 68,94 ton ha-1. Untuk rendemen diperoleh keempat sumber benih tersebut berturut-turut senilai 5,19 %, 6,21 %, 6,16 %, dan 5,77 %. Kedua komponen tersebut kemudian berpengaruh kepada estimasi nilai hablur yang didapatkan. Nilai hablurnya berurutan setinggi 3,93 ton ha-1, 4,15 ton ha-1, 3,90 ton ha-1, dan 3,98 ton ha-1., National sugar production not enough yet to fulfilled the needs, so that the supply shortage have to fulfilled through import. One of the activities in sugarcane cultivation that influences sugar result are depends on the provision and usement of it seeds. The internship program aims to analyzing the differences of productivity and yield of sugarcane from several seed sources in the working area of Madukismo Sugar Factory, Yogyakarta. Primary data are taken in the form of production estimates, brix measurements, and farmers interview. The result showing, there are no real difference. Productivity from plantations which seed sources come from sugar factory, breeder farmers, non-breeder farmers, and unknown seeds source with the values in order are 75,73 tonnes ha-1, 66,88 tonnes ha-1, 63,29 tonnes ha-1, and 68,94 tonnes ha-1. Regarding yield obtained of those four seed sources in order with values of 5,19 %, 6,21 %, 6,16 %, and 5,77 %. Those two components then affect the sugar crystal obtained. Crystal values in order as high as 3,93 tonnes ha-1, 4,15 tonnes ha-1, 3,90 tonnes ha-1, and 3,98 tonnes ha-1.
Keyword: brix, productivity, seed, sugar cane, yield

Judul: Pengelolaan Tanaman Tebu (Saccharum officinarum L.) di Pabrik Gula Madukismo, PT. Madubaru, Yogyakarta: dengan Aspek Khusus Mempelajari Produktivitas Tiap Kategori Tanaman
Abstrak: The study of the productivity of the various categories of sugarcane held in the Madukismo Millsworking area, Madubaru Company, Yogyakarta. This activity began in February 13 to May 14, 2012. The sample is taken at Sleman and Bantul district. The method used is the direct field observation, data from the division of plant productivity, as well as interviews with farmers. The results obtained on the productivity of down land is higher than up land. Differences in land characteristics influence the productivity of sugarcane. In addition, the downland productivity tended to decrease from the plant cane (PC) to ratoon crop (RC) in each subsequent season. For up land, there is higher productivity at ratoon cane I (RC 1) increase from low productivity in the plant cane (PC) and then back on every ratoon crop the following season. To overcome the low productivity of ratoon sugarcane needed to do the loading or replanting, or ratoon intensif nurse.
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Judul: Hamiltonian formulation for linear waves motion in two layers fluid
Abstrak: The surface wave could be considered as a wave that separates two fluids, namely water and air. Based on this assumption, it is introduced the interfacial wave, a wave between two layers of fluid with different density. The formulation of interfacial waves motion begins with deriving the base equation of irrotational ideal fluid. Furthermore, according to irrotational fluid assumption, the base equation can be stated in velocity potential. In this derivation, the fluids domain is assumed to be restricted by rigid lid boundary conditions, both at the upper and lower limit. Therefore, the interfacial waves motion can be explained in a hamiltonian formulation. In the hamiltonian formulation, total energy is defined as the sum of kinetic and potential energy. The hamiltonian system is obtained from reduction of kinetic energy by using the Dirichlet Neumann Operator. The resulted kinetic energy equation is nonlinear. Therefore, this form is linearized by first part of the Taylor expansion. This linearization gives a dispersion relation of linear wave. Based on this dispersion relation, the phase speed of the linear wave depends on the density ratio of the two layers fluid.
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