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: Pengelolaan Tanaman Tebu (Saccharum officinarum L.) di Pabrik Gula Madukismo, PT Madubaru, Yogyakarta dengan Aspek Khusus Mempelajari Produktivitas Tiap Kategori Tanaman dan Tipe Kemasakan.
Abstrak: Pengelolaan tanaman tebu dilakukan untuk menghasilkan produksi tebu serta rendemen yang optimal. Teknik budidaya yang belum baik serta keprasan yang lebih dari tiga kali menyebabkan produktivitas tebu mengalami penurunan. Kegiatan magang dilaksanakan mulai 6 Februari 2017 hingga 5 Juni 2017 di wilayah kerja PG. Madukismo, PT. Madubaru, Yogyakarta. Kegiatan magang ini secara khusus bertujuan untuk menganalisis produktivitas tiap kategori tanaman dan tipe kemasakan. Hasil pengamatan menunjukkan produktivitas pada lahan kering wilayah Bantul dan Purworejo naik pada kategori tanaman RC I kemudian turun pada kategori tanaman berikutnya. Produktivitas varietas masak tengah lambat wilayah Bantul lebih tinggi daripada wilayah Purworejo. Pengukuran brix yang dilakukan pada bulan Mei menunjukkan bahwa varietas masak tengah lambat memiliki rendemen yang rendah pada saat masa awal giling pabrik gula.
Keyword: awal giling, kemasakan, keprasan, rendemen

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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