Judul: Risiko Produksi Pendederan Ikan Hias Black Ghost pada Anggota Kelompok Tani Batara Mina Sejahtera di Kecamatan Bogor Utara
Abstrak: Ornamental fish is one of the potential fishery commodities which has some advantages than other fish. Black Ghost is one of the export ornamental fish commodities and has a potential business opportunity. One of the farmer groups in Bogor city is Batara Mina Sejahtera (BMS). The problem faced by BMS is different fish survival rate from the Black Ghost fish mortality. This research objectives are to identify production risk sources, to analyze the production status of risk, and to determine handling alternative to reduce the Black Ghost nursery production risk. This research use several method such as descriptive analyze, z-score, and Value at Risk. Sources of production risk in Black Ghost nursery of BMS members at North Bogor is different survival rate between farmer because mortality from water quality, seed quality, diseases, and human resources. The highest status risk production is water quality and the lowest risk sourcers is human resources. The handling alternative which can reduce of risk production are preventive and mitigation.
Keyword: production risks, ornamental fish, Black Ghost

Judul: Analisis Risiko Produksi Ikan Black Ghost di Unit Pendederan I Arifin Fish Farm Kota Bogor, Jawa Barat
Abstrak: Apteronotus albifrons known as the black ghost fish are fish that originated from South America. One of the fish farmers who produce fish black ghost in the city of Bogor is Mr. Arifin. Each production cycle fluctuations fish survival rate, this indicated the existence of risk. The purpose of this study is (1). identify risks faced by Mr. Arifin production in units of fish nursery I blackghost (2). analyzing the probability and impact of risk sources encountered Mr. Arifin in unit nursery I fish black ghost. (3). determine appropriate strategies to address the risks faced by Mr. Arifin production in the nursery unit I fish black ghost. Data obtained from field observation and interviews with business owners. Then the data were analyzed with descriptive methods and risk analysis. Results obtained by analysis of sources of risk in Arifin fish farm is changes in water quality, and fish disease attacking each other. Value of the probability and impact of each risk is 43,3% change in water quality and Rp 1,060,436, the disease was 48,0% and Rp 1,848,419, fish attacked each other at 34,5% and Rp 248,781. Sources of risk management strategies fish use to attack each other preventive strategies. Sources of risk management strategies and changes in water quality by using preventive and mitigation strategies.
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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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