Judul: Analisis Pendapatan dan Faktor-faktor yang Mempengaruhi Usatani Kubis (Brassica oleracea L) di Kecamatan Pangalengan Kabupaten Bandung Jawa Barat
Abstrak: Cabbage is one of the horticultural commodities which have contributed greatly to the national GDP in recent years. The purpose of this research was to analyze the income of farming and the factors that affected the level of cabbage production in Pangalengan Sub-District. The income analysis results using R/C showed that the cabbage farming in Pangalengan Sub-District was profitable to carry out because the value of R/C over the cash cost as well as the total cost was greater than one. The results of the regression analysis of production function by using the function of the Cobb-Douglass production showed that production factors for N element, seed, fertilizer, labor outside the family and labor inside the family were insignificant (real), while for the land area, P element, K element, liquid pesticides and solid pesticides were insignificant (unreal). Of all the variables being estimated, the use of labor outside the family negatively affected the cabbage production. Based on the addition of variable coefficient, the value obtained was 1.655, which is more than one, so that cabbage farming was considered irrational (inefficient). Therefore, the use of production factors can still be improved. The optimal combination to achieve efficient conditions can be generated by using the analysis of NPM and BKM.
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Judul: Analisis Faktor-Faktor yang Mempengaruhi Produksi dan Pendapatan Usahatani Kacang Panjang (Studi Kasus : Kecamatan Nagrak, Kabupaten Sukabumi)
Abstrak: Long Beans is one commodity that many consumption by society and ranks third from the types of vegetables that are consumed by the people of Indonesia. One of production center located in West Java and one of them is Sukabumi Based on the total area harvested vegetables in Sukabumi, commodity beans were the highest compared to other vegetable crop acreage to total crop area reached 27 percent of the total area harvested. Sukabumi consists of several subbean commodity producers, one of which is the District Nagrak. However, productivity in Sub Nagrak beans are low 8 tons per hectare is still below optimum productivity that can reach 15 to 20 tons per hectare.. Based on the above issues it is necessary to analyze what factors affecting bean productivity levels in Sub Nagrak and whether the farming activities in the District Nagrak is efficient. Based on the research that has been made known that the value of R / C ratio of the farm cash costs were 2.22 and R / C ratio of the total cost of 1.76 so that it can be said long bean farming activities efficiently and profitably, while production factors that influence including land, seed, fertilizer urea, TSP / SP 36, NPK, nutitions, labor, whereas no significant factors are pesticide.
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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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