Judul: Dampak Kenaikan Harga Kedelai Terhadap Tiga Usaha Kecil dan Menengah Tahu Kota Bogor
Abstrak: Inability to meet the needs of domestic soybeans make Indonesia dependence on imports. Consequently there is no certainty of domestic supply availability and price stability of soybean. The increased price of soybeans in the country influenced by the world soybean prices often occur and cannot be avoided by tofu industries that are consumers of imported soybeans. With the diversity of tofu business scale existing in Indonesia, the impact of rising soybean prices will vary from one tofu business to others. Therefore, this study uses three samples with different scale business to compare the impact of rising soybean prices. Classification of used business scale is based on the amount of daily production capacity, that is the scale of households with a daily production capacity of ≤ 100 kg, small scale with a daily production capacity of 101-200 kg, and medium scale with a daily production capacity of 201-300 kg. The indicators used in this study is the profitability value, value-added and sensitivity. The results obtained are that v medium-sized tofu businesses generate the highest profitability value and valueadded, and are the most resistant tofu business in encountering the increased soybean prices. However, the results obtained by medium-sized tofu businesses are not much different from the value obtained by small-sized tofu businesses. Thus, in this study, small and medium-sized tofu business generate insignificantly different profitability value, value-added, and the sensitivity.
Keyword: Bogor Agricultural University (IPB), tofu, profitability, value added, soybean price fluctuations

Judul: Pengaruh Kenaikan Harga Kedelai terhadap Profitabilitas dan Nilai Tambah Usaha Tahu Bandung Kayun-Yun di Desa Cihideung Hilir Kecamatan Ciampea Kabupaten Bogor
Abstrak: Small industries is part of SME (Small Medium Enterprise) sector that gives an important role in Indonesia’s economic development. One of small industry that potentially to be developed is soybean industries such as tofu industries. Soybean price increase that occurred in 2013 affects tofu small industrial especially Usaha tahu bandung Kayun-Yun. The purpose of this research was to analyze the effect of soybean price increase on profitability and added value of Usaha Tahu Bandung Kayun-Yun. Research location was selected with the considerations that Ciampea subdistricts is one of the all subdistricts in Bogor district that known as tofu production centers. The results showed after soybean prices increased, the total cost increased by 44 957 794 per month, sales volume is still in 6700 pieces per day, the difference in cost of production in the amount of Rp 206/piece for 4 cm tofu and Rp 254/piece for 5 cm tofu, break-even point in goods value for 4 cm tofu in the amount of 586 pieces with 175 873 rupiah IDR and for 5 cm in the amount of 330 pieces with 115 557 rupiah IDR. Profitability value showed an increase of 30.25 % for 4 cm and 29.36 % for 5 cm tofu. The result of the added value also increased by Rp 8 672/kg for 4 cm tofu and Rp 8 195/kilogram for 5 cm tofu.
Keyword: added value., profitability, Usaha tahu bandung Kayun-Yun, Soybean

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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