Judul: Kombinasi iradiasi dan penyimpanan pada suhu beku terhadap kandungan bakteri pada daging sapi asal rumah potong hewan di kabupaten serta kota Bogor
Abstrak: Beef contains nutrients such as protein and water content is so high that suitable media for microbial growth. The presence of microbial can degrade beef’s quality. Therefore it needs to do some efforts to slow the damage by microbes on the beef with frozen storage and use of irradiation technology. This study on the effect of frozen storage and irradiation of the content of bacteria in beef. Also performed to determine the concentration of protein and water, and identification of Salmonella. Meat samples taken from three Slaughter Houses (RPH) in the District and the City of Bogor. Storage carried out for 4 weeks in the freezer with irradiation doses of 0, 3 and 5 kGy. The results showed levels of protein in meat slaughterhouses A, B and C were irradiated with 0 kGy dose at week 0, respectively 67.95%, 61.13% and 70.40%, while the water content of beef slaughterhouses A, B and C, each for 75.31%, 74.26% and 73.91%. No Salmonella obtained from three samples of beef. In general, the dose of 3 kGy could eliminate the total aerobic bacteria, coliform, Escherichia coli and Staphylococcus spp. that meet the SNI (2008) in all three samples of beef and looks significantly different to that are not irradiated (p <0.05). Combination treatment of frozen storage with irradiation provides a real impact on reducing the total count of aerobic bacteria, coliform, Escherichia coli and Staphylococcus spp
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Judul: Kombinasi iradiasi dan penyimpanan pada suhu beku terhadap kandungan bakteri ikan bawal laut (Formio niger), kembung (Rastrelliger kanagurta), dan kuwe (Caranx ignobilis) asal pasar ikan Muara Angke Jakarta
Abstrak: Fish is one food that is widely consumed by the public. The sample used in this research consists of three species of fish, namely Marine Pomfret fish, Mackerel fish and Pompano fish. Irradiation is done by using Iradiator Panorama Serba Guna (IRPASENA) with 60Co sources at doses of 0, 3 and 5 kGy with dose rate 1,1 kGy/hour. Storage carried out for 0,1,2,3 and 4 weeks at a temperature of -17oC. Protein content was measured by using the "Nitrogen Micro Kjeldhal". The parameter measured were protein content, water content, as well as microbiological analysis using Total Plate Count (TPC) covering a total colonies of bacteria, Coliform, Staphylococcus and Salmonella. The results showed the protein levels of these three fish samples ranged from 73,2685 to 79,3167%. Water content of the three fish samples ranged between 76,11 – 79,57 %. Dose of 5 kGy was able to reduce the number of bacteria that meets the requirements of SNI and looks significantly different from non irradiated. Combination treatment of frozen temperature storage and irradiation can reduce the number of bacteria. The number of initial contamination of aerobic bacteria, Staphylococcus, Coliform and Escherichia coli has exceeded the allowable threshold of SNI. Salmonella was not found in all samples tested.
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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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