Judul: Analisis Pendapatan Penangkar Benih Kentang Bersertifikat Di Kecamatan Pangalengan, Kabupaten Bandung
Abstrak: Pangalengan district, Bandung regency is the center supplying of the source potato seeds certified. It is stated that some people make potato seeds farming as a family livelihood. The purpose of this study was to analyze farming income, household income, and farming income contribution to household income. The results of analysis farming income for potato seeds G-3 and G-4 certified, gain the value of R/C ratio is more than 1.
Keyword: household income., farming income, potatoes seed, Solanum tuberosum

Judul: Analisis Pendapatan Usahatani Kentang Yang Menggunakan Benih Sertifikat Dan Non Sertifikat Di Desa Girijaya, Kecamatan Cikajang, Kabupaten Garut
Abstrak: Meningkatnya kebutuhan benih kentang mendorong pemerintah untuk menciptakan benih kentang yang bermutu dan bersertifikat supaya dapat memenuhi kebutuhan dan ketersediaan benih serta meningkatkan produktivitas kentang Indonesia. Penelitian ini bertujuan untuk mendeskripsikan keragaan usahatani antara petani yang menggunakan benih sertifikat dan non sertifikat, menganalisis besaran penerimaan, biaya dan pendapatan usahatani antara petani yang menggunakan benih sertifiakt dan non sertifikat. Data dianalisis menggunakan analisis pendapatan usahatani dan uji statistik mann-whitney guna menganalisis pendapatan dan perbandingan pendapatan usahatani penggunaan benih kentang yang lebih menguntungkan. Hasil penelitian menunjukkan bahwa usahatani kentang benih sertifikat menghasilkan pendapatan yang lebih menguntungkan dibandingkan dengan petani yang menggunakan benih non sertifikat. Hal tersebut didukung oleh hasil uji beda statistik yang menyatakan bahwa terdapat perbedaan secara nyata antara petani yang menggunakan benih sertifikat dengan non sertifikat pada variabel produktivitas, penerimaan, pendapatan atas biaya tunai, pendapatan atas biaya total, dan R/C atas biaya total
Keyword: benih, kentang, pendapatan, sertifikat,

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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