Judul: Kadar Genistein dan Daidzein pada Kedelai, Ampas Tahu, dan Oncom Merah
Abstrak: Isoflavone (genistein and daidzein) can be found in Leguminosae, especially in soybean. Soybean can be processed into tofu and get around to tofu waste, which can be processed finally to “oncom merah”. Soybean, tofu waste, and “oncom merah” had been analysed in this research for genistein and daidzein contents. Soybean, tofu waste, and “oncom merah” were hydrolysed using 4 N HCl and ethanol, followed by partition using ethyl acetate. Components purification by flash chromatography and its contents were determined by high performance liquid chromatography. Genistein and daidzein contents of soybean were 128.69 mg/100g and 134.46 mg/100g, respectively. Tofu waste contained 65.93 mg/100g genistein and 63.68 mg/100g daidzein. Furthermore, genistein and daidzein contents of “oncom merah” were 32.41 mg/100g and 27.70 mg/100g. Soybean contained genistein and daidzein two times higher than tofu waste and four times higher than “oncom merah”.
Keyword: 

Judul: Genistein and Daidzein Content of Soybean, Tofu Waste, and “Oncom Merah”.
Abstrak: Isoflavone (genistein and daidzein) can be found in Leguminosae, especially in soybean. Soybean can be processed into tofu and get around to tofu waste, which can be processed finally to “oncom merah”. Soybean, tofu waste, and “oncom merah” had been analysed in this research for genistein and daidzein contents. Soybean, tofu waste, and “oncom merah” were hydrolysed using 4 N HCl and ethanol, followed by partition using ethyl acetate. Components purification by flash chromatography and its contents were determined by high performance liquid chromatography. Genistein and daidzein contents of soybean were 128.69 mg/100g and 134.46 mg/100g, respectively. Tofu waste contained 65.93 mg/100g genistein and 63.68 mg/100g daidzein. Furthermore, genistein and daidzein contents of “oncom merah” were 32.41 mg/100g and 27.70 mg/100g. Soybean contained genistein and daidzein two times higher than tofu waste and four times higher than “oncom merah”.
Keyword: 

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.
Keyword: