Judul: Pengaruh Penambahan Antioksidan dan Aktivator Untuk Mempertahankan Aktivitas Proteolitik Getah Pepaya Selama Penyimpanan
Abstrak: Indonesia is the fifth largest producers of papaya in the world. To increase its value, this raw material should be processed further to many kind products include papain. The Indonesian contribution of papain in international market is still low. Crystalline of papain can be made directly from fresh papaya latex. This method is considered more effective than when it is prepared from crude papain. The quality of pure papain relied on the quality of the papaya latex as raw material. With the appropriate handling, the proteolytic activity of the enzymes of the latex can be maintained during storage.
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Judul: Aktivitas Antioksidan Ekstrak Daun Papaya (Carica papaya (L). Var Kalina) dengan Perlakuan Tanah Lempung.
Abstrak: Penambahan tanah lempung pada proses perebusan daun pepaya bertujuan mengurangi rasa pahit, namun belum diketahui dapat mempengaruhi aktivitasnya sebagai antioksidan. Oleh karena itu, penelitian ini bertujuan menguji aktivitas antioksidan dan komponen bioaktif daun papaya berdasarkan cara pengolahan. Aktivitas antioksidan ditentukan dengan metode DPPH dan diukur dengan spektrofotometer pada panjang gelombang 517 nm. Hasil penelitian menunjukkan ekstrak air dan etanol daun papaya yang telah diberi perlakuan tergolong memiliki aktivitas antioksidan yang sangat lemah, aktivitas antioksidan yang paling tinggi terdapat pada perebusan selama tiga menit dinyatakan dalam bentuk IC50, yaitu 528.495 ppm ekstrak etanol. Aktivitas antioksidan ini ditimbulkan oleh kandungan metabolit sekunder pada daun papaya, yaitu flavonoid dan fenolik. Hasil analisis menunjukkan bahwa tidak ada pengaruh aktivitas antioksidan, fenolik, dan flavonoid total daun papaya yang direbus dengan penambahan tanah lempung (P>0.05).
Keyword: Antioksidan, daun papaya, fenolik, flavonoid, tanah lempung

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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