Judul: Effect of Certified Seeds on Production and Income of Sugar Cane Farming in East Java Province
Abstrak: Impor gula kristal mentah dan gula kristal rafinasi yang tidak terkontrol dapat memicu tergesernya keberadaan gula kristal putih dalam pasar domestik. Diperlukan pasokan tebu yang cukup agar kinerja pabrik gula untuk melakukan penggilingan tidak terhambat karena bahan baku yang terbatas. Salah satu upaya yang dapat diterapkan untuk meningkatkan produksi tebu adalah strategi intensifikasi. Penggunaan benih bersertifikat adalah salah satu upaya intensifikasi yang fokus pada perbaikan kualitas input. Jaminan mutu dan keaslian yang diberikan benih bersertifikat diharapkan dapat memberikan perbedaan terhadap kualitas maupun kuantitas produksi tebu. Oleh karena itu, penelitian ini bertujuan untuk menganalisis struktur biaya, penerimaan, pendapatan serta hasil panen usahatani tebu berdasarkan jenis benih yang digunakan. Metode uji beda yang digunakan untuk melihat perbedaan adalah uji u mann-whitney. Hasil uji statistik menunjukkan bahwa secara signifikan terdapat perbedaan produksi dan pendapatan usahatani tebu yang lebih tinggi setelah petani mengadopsi benih bersertifikat., Uncontrolled imports of raw crystal sugar and refined crystal sugar can trigger a shift in the presence of white crystal sugar in the domestic market. Adequate supply of sugar cane is needed so that the performance of sugar mills in milling is not hampered due to limited raw materials. One effort that can be implemented to increase sugarcane production is an intensification strategy. The use of certified seeds is one of the intensification efforts that focus on improving input quality. Quality assurance and authenticity provided by certified seeds are expected to make a difference to the quality and quantity of sugar cane production. Therefore, this study aims to analyze the cost structure, revenue, income and yields of sugar cane farming based on the type of seed used. The difference test method used to see the difference is the Mann-Whitney u test. Statistical test results show that there is a significant difference in the production and income of sugar cane farming after farmers adopt certified seeds.
Keyword: Certified seeds, Cost structure, Income, Production, Sugarcane

Judul: Analysis of Factors Affecting Production an Income of Sugarcane in East Java Province
Abstrak: Meningkatnya konsumsi gula di Indonesia meningkatkan permintaan gula, sehingga diperlukan peningkatan produksi tebu nasional. Namun produksi tebu setiap tahunnya cenderung menurun sehingga Indonesia masih perlu mengimpor gula, terutama gula mentah. Penelitian ini bertujuan untuk mengetahui faktor-faktor yang memengaruhi produksi dan menganalisis pendapatan petani tebu di Jawa Timur. Penelitian ini menggunakan data 2909 petani pada Sensus Pertanian 2013 Badan Pusat Statistika. Pendapatan usahatani dianalisis dengan R/C yang dibedakan menurut luas lahan arealnya. Faktor-faktor yang memengaruhi produksi tebu dianalisis menggunakan fungsi produksi Cobb Douglass. Hasil penelitian menunjukan bahwa luas lahan, bibit, pupuk unsur N, dan tenaga kerja memengaruhi produksi tebu. Rasio R/C menunjukan bahwa usahatani tebu dengan lahan sempit lebih efisien. Biaya tenaga kerja merupakan biaya terbesar untuk pertanian tebu lahan besar. Hasil penelitian menunjukan bahwa pemberian kredit produksi diperlukan untuk usahatani tebu skala besar., The increasing consumption of sugar in Indonesia increases the demand for sugar, so it is necessary to increase national sugarcane production. However, sugarcane's annual production tends to decline. Therefore Indonesia still needs to import sugar, especially raw sugar. The research aims to determine the factors that affect the production and analyze sugarcane farmers' income in East Java Province. This study used 2909 farmer’s data of Agricultural Census 2013, Central Bureau of Statistics. Farm income was analyzed using R/C analysis, which is differentiated according to its area. The factors affecting sugarcane production were analyzed using the Cobb-Douglas production function. The results showed that area, seeds, nitrogen unsure fertilizer, and labor affected sugar cane production. The R/C ratio indicated that small-size sugarcane farming was more efficient. The cost of hired labor was the highest cost for large-size sugarcane farming. This finding implies that production credit provision is needed for extensive sugarcane farming.
Keyword: agriculture, cost structure, land area, sugar cane

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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