Judul: Factors Affecting Production and Income of Ginger in Center Java
Abstrak: Jahe merupakan komoditas biofarmaka unggulan sebagai bahan baku Industri Obat Tradisional. Namun perkembangan produktivitas jahe pada enam tahun terakhir cenderung menurun. Penelitian ini bertujuan untuk mengetahui faktor-faktor yang memengaruhi produksi dan pendapatan usahatani jahe. Analisis faktor produksi akan dianalisis menggunakan model fungsi produksi Cobb-Douglas dan pendapatan usahatani menggunakan analisis pendapatan dan R/C ratio . Hasil penelitian menunjukkan bahwa faktor yang berpengaruh nyata meningkatkan produksi jahe adalah benih, pupuk kimia, pupuk organik, tenaga kerja dan dummy pola tanam monokultur-tumpang sari. Usahatani jahe yang dijalankan oleh petani di Jawa Tengah menguntungkan karena memperoleh pendapatan yang bernilai positif. Apabila dilihat berdasarkan luas lahan, usahatani yang dijalankan pada lahan sempit memperoleh pendapatan lebih tinggi dibandingkan dengan usahatani lahan luas, namun memberikan R/C ratio lebih rendah. Apabila dilihat berdasarkan pola tanam, usahatani monokultur memperoleh pendapatan lebih tinggi dibandingkan dengan usahatani tumpang sari., Ginger is a leading biopharmaceutical commodity as a raw material for the Traditional Medicine Industry. However, the development of ginger productivity in the last six years tends to decline. This study aims to determine the factors that affect the production, and income of ginger farming. Production factor analysis was analyzed using the Cobb-Douglas production function model. Farm income is analyzed using income analysis, and the R/C ratio is differentiated according to plant area and cropping pattern. The analysis showed that the factors that significantly affected ginger production were seeds, chemical fertilizers, organic fertilizers, labor, and dummy cropping patterns of monoculture-double cropping. Ginger farming, which farmers run in Central Java is profitable because it gets a positive income. When viewed based on the plan area, farms run on narrow learn higher income compared to large land farming, but provide a lower R/C ratio. When viewed based on cropping patterns, monoculture farming earns higher income compared to double cropping farming.
Keyword: ginger, income, production

Judul: Factors Affecting Production and Income of Ginger in Center Java
Abstrak: Jahe merupakan komoditas biofarmaka unggulan sebagai bahan baku Industri Obat Tradisional. Namun perkembangan produktivitas jahe pada enam tahun terakhir cenderung menurun. Penelitian ini bertujuan untuk mengetahui faktor-faktor yang memengaruhi produksi dan pendapatan usahatani jahe. Analisis faktor produksi akan dianalisis menggunakan model fungsi produksi Cobb-Douglas dan pendapatan usahatani menggunakan analisis pendapatan dan R/C ratio . Hasil penelitian menunjukkan bahwa faktor yang berpengaruh nyata meningkatkan produksi jahe adalah benih, pupuk kimia, pupuk organik, tenaga kerja dan dummy pola tanam monokultur-tumpang sari. Usahatani jahe yang dijalankan oleh petani di Jawa Tengah menguntungkan karena memperoleh pendapatan yang bernilai positif. Apabila dilihat berdasarkan luas lahan, usahatani yang dijalankan pada lahan sempit memperoleh pendapatan lebih tinggi dibandingkan dengan usahatani lahan luas, namun memberikan R/C ratio lebih rendah. Apabila dilihat berdasarkan pola tanam, usahatani monokultur memperoleh pendapatan lebih tinggi dibandingkan dengan usahatani tumpang sari., Ginger is a leading biopharmaceutical commodity as a raw material for the Traditional Medicine Industry. However, the development of ginger productivity in the last six years tends to decline. This study aims to determine the factors that affect the production, and income of ginger farming. Production factor analysis was analyzed using the Cobb-Douglas production function model. Farm income is analyzed using income analysis, and the R/C ratio is differentiated according to plant area and cropping pattern. The analysis showed that the factors that significantly affected ginger production were seeds, chemical fertilizers, organic fertilizers, labor, and dummy cropping patterns of monoculture-double cropping. Ginger farming, which farmers run in Central Java is profitable because it gets a positive income. When viewed based on the plan area, farms run on narrow learn higher income compared to large land farming, but provide a lower R/C ratio. When viewed based on cropping patterns, monoculture farming earns higher income compared to double cropping farming.
Keyword: ginger, income, production

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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