Judul: Keanekaragaman spesies tumbuhan asing invasif di Kampus IPB Darmaga, Bogor
Abstrak: Kampus IPB Darmaga dengan luas sekitar 256,97 ha memiliki tutupan vegetasi yang beragam, baik itu vegetasi homogen maupun campuran yang digunakan sebagai kebun percobaan dan ruang terbuka hijau. Vegetasi yang ada di kampus ini sebagian berasal dari spesies introduksi. Introduksi spesies ini adakalanya dapat mengganggu ekologi tumbuhan yang ada di kampus ini, terutama tumbuhan yang bersifat invasif. Sehubungan dengan itu, maka perlu dilakukan penelitian mengenai spesies tumbuhan asing invasif untuk mengidentifikasi komposisi spesies dan pola penyebaran spesies tumbuhan asing invasif di Kampus IPB Darmaga. Penelitian ini dilakukan pada Bulan Januari–Februari 2011 di sepuluh unit lokasi, yaitu Arboretum Fahutan, Arboretum Hutan Tropika, Arboretum Lanskap, Hutan di samping Masjid Al-Hurriyyah, Hutan Cikabayan, Tegakan Karet di depan Rusunawa dan Asrama C4 Silva, Tegakan Jati Sengked, Tegakan Pinus Cangkurawok, dan Tegakan Sengon Rektorat. Pengambilan data dilakukan dengan analisis vegetasi menggunakan metode petak ganda ukuran 2 m x 2 m, jarak antar petak 5 m, dan sebanyak 25 petak contoh untuk setiap unit lokasi. Identifikasi spesies tumbuhan asing invasif menggunakan buku panduan lapang Webber (2003) dan ISSG (2005). Jumlah spesies hasil analisis vegetasi yang dapat diidentifikasi sebanyak 153 spesies dari 60 famili. Tegakan Pinus Cangurawok memiliki komposisi spesies tumbuhan tertinggi, yakni 56 spesies dari 33 famili, sementara Tegakan Karet di depan Asrama C4 Silva memiliki komposisi spesies terendah, yakni 26 spesies dari 19 famili. Spesies tumbuhan yang tergolong spesies asing invasif di Kampus IPB Darmaga berjumlah sebelas spesies dari sembilan famili yaitu; Ageratum conyzoides L. (Asteraceae), Chromolaena odorata (L.) King & H.E.Robins (Asteraceae), Clidemia hirta G. Don. (Melastomataceae), Elaeis guineensis Jacq. (Arecaceae), Lantana camara L. (Verbenaceae), Mikania micrantha H.B.K (Asteraceae), Mimosa pudica Duchass & Walp. (Fabaceae) Piper aduncum L. (Piperaceae), Rubus moluccanus L. (Rosaceae), Spathodea campanulata Beauv. (Bignoniaceae), dan Swietenia macrophylla King. (Meliaceae). Sementara itu, pola penyebaran seluruh spesies tersebut adalah mengelompok.
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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: 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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