Judul: Sebaran Spasial Tumbuhan Obat yang Dimanfaatkan Masyarakat Kampung Nyungcung, Desa Malasari, Kecamatan Nanggung, Kabupaten Bogor.
Abstrak: Nyungcung kampoong is least developed village, situated in Nanggung sub-district. The community of the kampoong utilized medicinal plant from its sorrounding location included forest area. For the purposes of management, spatial distribution mapping is very important. The purpose of the study is to identify the diversity and forms of utilzation as well as biophysical characteristics and accessibility. Data collection, interview and field observation were conducted in March 2015 in Nyungcung kampoong, Village Malasari, Nanggung subdistrict, Bogor. Result showed that there were 140 species of medicinal plants utilized by the community. Among the medicinal plants species family Zingiberaceae was the most predominantly utilized located in home garden and upland field. The average distance medicinal plants from the house was about 214 meters from the house situated on 600–800 meters above sea level, with gentle slope. Community utilized medicinal plants that located at its surrounding house. This is due to the fact that they have conducted domestication of the wild species from the forest. This showed that community contribute to forests conservaton.
Keyword: distribution, medicinal plant, utilization

Judul: Sebaran Spasial Tumbuhan Pangan yang Dimanfaatkan Masyarakat Kampung Nyungcung, Desa Malasari, Kecamatan Nanggung, Kabupaten Bogor.
Abstrak: Nyungcung Kampong is one of the kampong which has variety local food. The purposes of this research are to identify character of food and its utilization type. In addition, character biophysical condition and its accessibility in Nyungcung Kampong community are recorded. Data were collected by literature study, interview, and observation. The result showed that there are 155 crops species from 61 families that are utilized by the local people and most of them are from Fabaceae families. The most widely used was the fruits and tree. In comparisn with wild species, cultivated plants mostly utilized. In term of spatial distribution, the plants were found at eleveation of about 700-800 mdpl. The nearest plant distribution area was located 22.12 meters and the farest was 413.43 meter from their house.
Keyword: crops, nyungcung kampong, spatial distribution

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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