Judul: Variasi ciri morfologi kutu tempurung hijau Coccus viridis (Green) (Homoptera: Coccidae) yang disebabkan oleh perbedaan tanaman inang
Abstrak: Tujuan penelitian ini untuk mengetahui variasi ciri morfologi luar kutu tempurung hijau pada tanaman kopi, jam bu batu, dan cengkeh, serta menyempurnakan deskripsi kutu tempurung hijau. Penelitian dilakukan antara bulan Oktober 1985 hingga Maret 1986 di tiga tempat, yaitu Cisarua pada ketinggian lebih kurang 650 meter di atas permukaan laut, Tajur pada ketinggian lebih kurang 300 meter di atas permukaan laut, dan Lentengagung pada ketinggian lebih kurang 50 meter di atas permukaan laut. Contoh kutu diambil dari tanaman kopi jenis robusta, jambu batu jenis lokal, dan cengkeh jenis Zanzibar. Masing-masing jenis tanaman dipilih secara acak sejumlah lima pohon tiap lokasi. Dari tiap pohon dipilih ..
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Judul: Analisis Keragaman Morfologi Koleksi Tanaman Kopi Arabika dan Robusta Balai Penelitian Tanaman Industri dan Penyegar Sukabumi
Abstrak: Coffee (Coffea sp.) is one of the plantation plant which have become commodities that counts in national income strengthening. This study aimed to identify and analyze the morphological diversity characters of arabica and robusta coffee genotypes collection in Sukabumi Industrial and Freshener Crops Research Institute. The experiment was conducted by characterization of 11 genotypes the coffee using a descriptors list which have been modified for the coffee plants. Most of the quantitative data were analyzed by analysis of covariance and others analyzed by analysis of variance. Qualitative and some of quantitative data were analyzed by analysis of quantitative data to get a dendogram clusters. The results of the morphological identification of arabica and robusta coffee plant showed some real differences between the genotypes both the variables that can be combined or can not be combined. The results of the dissimilarity relation dendogram shows the level of the coffee plant arabica and robusta coffee kinship approximately 0.45 (45%) of the observed variables. Robusta coffee has a higher level of similarity than arabica coffee.
Keyword: Bogor Agricultural University (IPB), genotypes, dendogram, covariance, clusters, characterization

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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