Judul: Keanekaragaman Spesies Tumbuhan Langka dan Sebarannya di Kampus IPB Darmaga
Abstrak: Various vegetation cover in IPB Darmaga Campus makes this place has plenty kinds of plants including naturally and wildly grown plants. Some of the plants are included as rare plants species. The rare plants species are potential to be utilized as media for conservation education. However, there’s no research yet about those rare plants and its distribution in IPB Darmaga Campus. The purpose of this research was to identify, determine the distribution, and document the history of rare plants species in IPB Darmaga Campus. Based on this research, there were 30 rare plants species from 18 families. Dipterocarpaceae was recorded as the dominating family. These rare plants species were dominated by tree habitus and were distributed in the whole area of IPB Darmaga, but mostly found in Faculty of Forestry area. These species were mostly planted by lecturers and alumni of Faculty of Forestry, Bogor Agricultural University (IPB). The purpose is for collection and student learning media.
Keyword: Bogor Agricultural University (IPB), rare plants species, IPB Darmaga Campus, conservation education

Judul: Keanekaragaman dan Kegunaan Spesies Tumbuhan Bawah di Tegakan Sawit Kebun Percobaan Cikabayan Kampus IPB Darmaga
Abstrak: Tumbuhan bawah yang tumbuh dibawah tegakan tanaman kelapa sawit sering kali dianggap merugikan. Pengetahuan masyarakat terkait pemanfaatan tumbuhan bawah yang ada di tegakan kelapa sawit perlu dikaji dan didokumentasikan agar ada tindak lanjut pemanfaatan. Penelitian ini bertujuan untuk mengidentifikasi keanekaragaman serta kegunaan spesies tumbuhan bawah yang ada di tegakan kelapa sawit kampus IPB Darmaga sebelum dan sesudah dilakukan pemupukan. Metode penelitian ini dilakukan dengan analisis vegetasi dan studi literatur. Keanekaragaman spesies tumbuhan bawah yang ditemukan sebanyak 82 spesies yang berasal dari 36 famili. Kegunaan spesies tumbuhan terdiri dari tumbuhan pangan, tumbuhan obat dan tumbuhan hias. Manfaat spesies tumbuhan yang paling banyak adalah sebagai tumbuhan obat.
Keyword: species diversity, undergrowth, utility

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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