Judul: Etnobotani Kepuh (Sterculia foetida L.): studi kasus pada masyarakat Desa Tepus Kabepaten Gunungkidul
Abstrak: Ethnobotany is the scientific study of the relationships that exist between peoples and plants. Java olive ( Sterculia foetida L.) is one of the species of plants that started rare found in Java. Tepus village of Gunungkidul district are the regional that are still found java olive tree. Output from the research material is consideration java olive preservation. The research was done with the semistructured methods by applying a technique snowball interview and analysis vegetation. Java olive used by community as food fodder, keep water, producing fuel, medicine, and the craft. While the part used which is leaves, bark, fruit, seeds , and wood. The research results obtained 10 individual Sterculia foetida L. (9 individual levels of the tree and 1 individual level of the poles). Tree height of java olive in the Tepus varies from 6 to 20 meters , while in diameter 14 to 115 cm. Tufted herbs java olive was fell around habitats such as petai cina (jumbie bean) , suggar apples , mahogany, kukun, gliricidia, the kapok, and teak. Characteristic of a constituent of habitats kepuh abiotik factor is the average temperature environment 26.5oC with the average moisture 81.9 % and the height of the growing over 100 m asl and under 500 m asl.
Keyword: Bogor Agricultural University (IPB), Tepus village, java olive, Gunungkidul district, ethnobotany

Judul: Etnobotani dan Potensi Tumbuhan Berguna di Kampung : Keay, Kabupaten Kutai Barat, Kalimantan Timur.
Abstrak: Keay Village is one of villages in West Kutai Regency, East Kalimantan. There are four ethnic groups occupying this village, i.e. Dayak, Javanese, Toraja, and Bugis. Dayak is the dominant ethnic group occupying the village, which still has traditional wisdom/knowledge in plants use. Ethnobotany is expected to document and hand on the knowledge of Dayak Benuaq ethnic group in using plants, and keep the knowledge from being loss. Data were collected through literature study, interview, field survey and inventory, vegetation analyses, and herbarium collection. Data on plants species found were classified in to classification of use, classification of illnesses, habitués percentage and parts of plants used, important value index, Shannon-Wienner species diversity index, and percentage of useful plants potential. There were 396 plant species found through ethnobotany and vegetation analyses, which was categorized into three categories i.e. plant species found through ethnobotany (285 species), plant species found through vegetation analyses in natural forest (158 species), plant species found through vegetation analyses in hevea plantation (34 species). There were 285 species belong to 78 families which uses had been known and grouped into 16 use groups. There were 53,79% of plants species in natural forest had the potential as useful plants, while in hevea plantation there were 50% of that species had the potential as useful plants. Dominant plant species in natural forest was keranyiq (Fordia johorensis) with IVI (Important Value Index) of pole level as much as 19,69%, sapling (25,46%), and seedling (24,67%). In hevea plantation, dominant plant species was hevea (Hevea brasiliensis) with IVI the highest IVI of tree level as much as 300%, pole (284,63%), sapling (143,59%), and seedling (52,42%). Plants use most widely used for medicinal as much as 95 species of 43 families. The community uses more plants from the forest than from the plantation, because there were more useful plants species in the forest. Potential useful plants at the forest of Keay village included mara uleq (Eurycoma longifolia), uwe (Korthalsia sp., Calamus sp., Daemonorops sp.), empulung (Asplenium nidus), and kerakap (Platycerium bifurcatum). Other potential other than plants potential in the natural forest was hevea (Hevea brasiliensis).
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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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