Judul: Karakterisasi Beberapa Varietas Jeruk Keprok Dataran Rendah
Abstrak: The research was conducted to characterize germplasms of Mandarins which have orange or orange-yellow epicarp color that is well-adapted in lowlands. Characterization was conducted on citrus in Padang Pangrapat and Rantau Panjang Village, Paser Regency, East Kalimantan, and Linggamanik Village, Cikelet District and Mekardaya Village, Bayongbong District, Garut in May-August 2012. The observations were referring to Descriptors for Citrus (International Plant Genetic Resources Institute, 1999). The character of observed citrus were compared with the similar variety that have been released by the Ministry of Agriculture; namely Keprok Borneo Prima (East Kalimantan), and Keprok Garut (Garut). The results showed that the citrus obtained in Padang Pangrapat and Rantau Panjang Village were not different each other, but different from Keprok Borneo Prima. The citrus obtained at Linggamanik Village was different from Keprok Garut. The citrus obtained at Mekardaya Village was similar to Keprok Garut.
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Judul: Karakterisasi Morfologi Dan Pertumbuhan Vegetatif Bibit Tujuh Varietas Jeruk Keprok (Citrus Reticulata Blanco).
Abstrak: Jeruk keprok (Citrus reticulata Blanco) merupakan salah satu jeruk yang buahnya memiliki warna kulit kuning atau oranye. Jeruk keprok memiliki berbagai macam varietas lokal berdasarkan daerah asal penanaman. Tujuan penelitian ini adalah untuk mengetahui keragaman karakter morfologi dan pertumbuhan 7 varietas jeruk keprok pada saat pembibitan. Penelitian ini menggunakan Rancangan Kelompok Lengkap Teracak (RKLT) dengan satu faktor yakni varietas. Bibit jeruk keprok yang diamati terdiri dari tujuh varietas yakni Berasitepu, Borneo Prima, Garut, Kacang, Madura, Tejakula, dan Terigas. Hasil penelitian menunjukkan bahwa karakter antar varietas memiliki keragaman. Perbedaan pada karakter kualitatif yaitu ujung daun, tepi daun, kepadatan duri, sudut percabangan, bentuk petiole, intensitas warna daun, bentuk duri, duri, dan kepadatan percabangan. Perbedaan pada karakter kuantitatif yaitu panjang duri, panjang daun, lebar daun, dan tebal daun. Hasil penelitian menunjukkan bahwa laju pertumbuhan bibit antar varietas tidak berbeda nyata.
Keyword: berasitepu, borneo prima, garut, kacang, madura, tejakula, terigas

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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