Judul: Pencemaran Salmonella sp. dalam Daging Ayam Beku yang Dilalulintaskan Melalui Pelabuhan Penyeberangan Merak
Abstrak: This study aims to determine the presence of Salmonella sp. as a safety indicator on frozen chicken meat transported through Merak port. This study used 53 samples of frozen chicken meat from Jakarta, Bekasi, Bogor, and Serang. The number of the samples 16, 11, 8, and 18 respectively. Two samples from Serang (3.77% of 53 samples) are found positive Salmonella sp., while from Jakarta, Bekasi and Bogor are negative. Total percentage samples from Serang positive Salmonella sp. is 11.1% of 18 samples. Based on SNI 01-7388-2009 about the Maximum Contaminant Limit of Microbes in the food, the presence of Salmonella sp. in frozen chicken meat should be negative.
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Judul: Tingkat Prevalensi Escherichia coli Dalam Daging Ayam Beku Yang Dilalulintaskan Melalui Pelabuhan Penyeberangan Merak
Abstrak: The aimed of this study was to determine prevalence of Escherichia coli in frozen chicken meat transported through Merak port. The samples were taken from DKI Jakarta (16 samples), Bekasi (11 samples), Bogor (8 samples), and Serang (18 samples). The average number of E. coli in frozen chicken meat from DKI Jakarta was 0.43x101±0.28x101 MPN/g, Bekasi was 10.4x101±33.04x101 MPN/g, Bogor was 0.28x101±0.23x101 MPN/g, and Serang was 6.72x101±25.79x101 MPN/g. Based on the result of ANOVA, the four areas had no significance in diferrence (p>0.05). The conclusion of this study showed that the average number of E. coli from Bekasi and Serang were over the maximum limit of microbial contamination as permitted by SNI 01-7388-2009 (1x101 MPN/g), whereas DKI Jakarta and Bogor were under the maximum limit. The prevalence of E. coli in frozen chicken meat from DKI Jakarta was 31.25%, Serang 27.78%, Bekasi 27.27%, and Bogor 12.50%. Keywords: Escherichia coli, frozen chicken meat, Merak port.
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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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