Judul: Kajian Aktivitas Antibakteri Ekstrak Tempe Komak terhadap Bakteri Staphylococcus aureus dan Escherichia coli
Abstrak: Tempe is a modified product fermented by Rhizopus sp. which contains active substances, such as antibacterial substances. The objectives of the study are to compare the yield of hyacinth tempe and bench-scale soybean tempe and to determine the antibacterial activity from hyacinth tempe against bacteria: Staphylococcus aureus and Escherichia coli. The yield is determined by comparing the tempe’s mass and bean’s mass. The antibacterial activities of the extracts are analyzed using well diffusion method. The study shows that the yield of hyacinth tempe (154 %) is higher than the yield of bench-scale soybean (151 %). The study also shows that hyacinth tempe extract has no antibacterial activity against S. aureus 0.0 mm, while commercial-scale and bench-scale soybean tempe extract have antibacterial activity against S. aureus, respectively, 8.9 mm and 7.0 mm. However, all of the tempe extract have no antibacterial activity against E. coli. The raw material of tempe gives contribution to produce antibacterial substance against S. aureus during fermentation by R. oligosporus.
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Judul: Pengaruh jenis Kapang terhadap mutu kimia dan aktivitas antimikroba Tempe Kacang Merah (phaseolus vulgaris L.)
Abstrak: Tempe merupakan salah satu pangan yang banyak digemari di Indonesia. Selain kedelai, bahan baku dalam pembuatan tempe bermacam-macam, salah satunya ialah kacang merah. Kandungan gizi tempe kacang merah dengan kedelai memiliki sedikit perbedaan, namun masih tergolong tinggi. Selain kandungan gizinya yang tinggi, tempe juga menghasilkan senyawa antimikroba yang dapat bermanfaat bagi penderita diare. Dalam pembuatan tempe, peranan laru tempe mempengaruhi hasil dari produk jadi tempe. Laru yang paling banyak digunakan ialah R. oligosporus dan R. oryzae. Karakteristik kedua kapang ini berbeda sehingga akan berpengaruh pada tempe yang dihasilkan. Dalam penelitian ini, akan dilihat pengaruh jenis kapang terhadap mutu kimia tempe dan aktivitas antimikrobanya. Pengujian antimikroba dilakukan dengan metode sumur dengan menggunakan bakteri S.aureus sebagai bakteri gram positif dan E.coli sebagai bakteri gram negatif. Hasil penelitian menunjukkan bahwa tempe kacang merah dengan kapang R. oligosporus menghasilkan mutu terbaik dari segi kandungan asam amino dan antitripsin. Kadar asam amino tertinggi ialah tempe dengan penambahan kapang campuran dalam satu laru, yaitu sebesar 314396 mg/kg. Namun tempe dengan laru Rhizopus oligosporus dan tempe dengan penambahan kapang campuran dalam satu laru memiliki kadar asam amino yang tidak berbeda nyata pada taraf signifikansi 0.05. Selain itu, tempe kacang merah dengan kapang R. oligosporus mempunyai kandungan antitripsin paling rendah, yaitu 8360.4 TUI, bila dibandingkan dengan tempe kacang merah yang lainnya. Keempat tempe kacang merah yang dihasilkan tidak mengandung oligosakarida dan tidak memiliki aktivitas antimikroba terhadap bakteri S. aureus dan E. coli., Tempeh is one of favourite food in Indonesia. In addition to soybean, raw materials for the manufacture of tempeh are various, one of them is red bean. Nutrient content of red bean tempeh with soybean have a slight difference, but still relatively high. In addition to its high content of nutrition value, tempeh also produces antimicrobial compounds that can be beneficial for patients with diarrhea. In the making of tempeh, mold is the one who will affect the product. The most commonly used of mold are R. oligosporus and R. oryzae. The characteristics of each molds are different, and it affects the result of tempeh. This research shows the influence of mold types in the chemical qualities of tempeh and antimicrobial activity. The testing of antimicroba was conducted using wells method with S. aureus as gram positive bacteria and E.coli as gram negative bacteria. The result shows that red bean tempeh with R. oligosporus produces the best quality in terms of amino acids and antitrypsin. The highest levels of amino acid is in tempeh C, i.e., 314396 mg/kg. However, tempeh B and tempeh C have no significantly different in level of amino acid (α<0.05). In addition, red bean tempeh with R. oligosporus have the lowest level of antitrypsin, i.e., 8360.4 TUI, if it compares to others. Four red bean tempeh do not contains oligosaccharide in all treatments, and they do not have antimicrobial activity against S. aureus and E. coli.
Keyword: Kacang merah, tempe, mutu kimia, aktivitas antimikroba

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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