Judul: Respon Pertumbuhan Bibit Angsana (Pterocarpus indicus Willd.) terhadap Media Tumbuh, Pemotongan Akar Lateral, dan Pemberian Urin Sapi
Abstrak: Pembibitan merupakan suatu proses dalam menghasilkan bibit yang berkualitas. Kualitas bibit, salah satunya ditentukan oleh mutu fisik-fisiologis yang meliputi batang berkayu, kesehatan, tinggi, diameter, jumlah daun, dan warna daun serta kekompakan media. Mutu bibit jenis angsana dalam penelitian ini diamati dengan menggunakan beberapa media tumbuh, pemotongan akar lateral, dan pemberian urin sapi dengan beberapa konsentrasi serta pupuk organik cair sampai bibit berumur 13 minggu. Penelitian dirancang menggunakan metode acak lengkap (RAL) dalam split plot design dengan 3 media tumbuh, 10 kombinasi perlakuan pemotongan akar dan pemupukan dengan menggunakan 9 bibit tiap perlakuan. Parameter yang diamati selama penelitian adalah tinggi bibit (cm), diameter bibit (mm), kekokohan bibit, berat kering total (g), rasio pucuk akar, warna daun dan kekompakan akar. Hasil penelitian menunjukkan bahwa media campuran tanah dan pupuk kandang (M2) dengan perlakuan pemotongan akar, pemberian 20% urin sapi dan 5% EM4 (A2), merupakan perlakuan terbaik bagi bibit angsana dengan nilai ratarata tinggi 46.25 cm, diameter 6.09 mm, kekokohaan bibit 6.56, beratt kering total 7.78 g, rasio pucuk akar 1.89, warna daun hijau dan kekompakan akar termasuk kategori kompak.
Keyword: Pterocarpus indicus Willd, kualitas bibit, pemotongan akar lateral, urin sapi

Judul: Pengaruh Pematahan Dormansi Terhadap Kemampuan Perkecambahan Benih Angsana (Pterocarpus Indicus Will)
Abstrak: INTRODUCTION. So far, Seedling production of Angsana (Pterocarpus indicus Will) is done by stem cutting. Seedling propagation by seeds is not done widely, as well as its silvicultural system is still not known yet. Seed germination percentage is affected strongly by seed quality (physic, genetic and physiology). The main problem of seed germination of Angsana seeds is seed coat dormancy; therefore it is important to study the breaking dormancy techniques of Angsana seeds. The aim of this research was to study the effects of breaking dormancy treatment to the germination capacity of Angsana seeds. MATERIAL AND METHOD. This research was done from 30 June to 28 Agust 2008 at Green House, the Laboratory of Silviculture, Faculty of Forestry, Bogor Agricultural University. The material and equipment used in this experiment consisted of Angsana seeds, hot water, H2SO4, KNO3, water from fermented bamboo shoots (Gigantochloa apus Kurz), rice hull charcoal, subsoil, germination boxes, soaking bath, watering equipment, analytical balance, stationary, ruler, calliper, and digital camera. The research procedures consisted of several steps; those were seed extraction and selection, seed water content measurement, breaking dormancy treatments, germination, maintenance, observation, and data collection and analysis. The experimental design in this research was completely randomised design which consisted of 6 soaking treatments, those were soaking in hot water for 30 minutes followed by soaking in cold water for 12 hours (B0), soaking in the fermented bamboo shoot liquid for 12 hours (B1), soaking in H2SO4 1% for 10 minutes (B2), soaking in H2SO4 1 % for 15 minutes (B3), soaking in KNO3 1 % for 12 hours (B4) and soaking in KNO3 for 24 hours (B5). Each experiment unit was replicated in three replicates. The observed parameters consisted of germination capacity, germination value, speed of germination, germination rate, germination time at 80%, high and diameter of transplanted seedlings. The collected data was analysed using F test followed by Duncan Multiple Range Test (DMRT). RESULTS AND CONCLUSSION. Angsana seeds had embryonic and seed coat dormancies. Based the results of F test and Duncan test showed that soaking in H2SO4 1% for 10 minutes and in KNO3 1 % for 24 hours could break those dormancies. It was indicated by it high germination percentage (100 %), and other values such as germination value (1,13% to 1.05% normal germinants/day2), germination speed (1, 41 %/day), germination rate (19,32 – 18,59 day), germination time at 80% (25 day), seedlings height (1,53 cm) , and diameter growth (1,06 mm to 1,1 mm) respectively. Key word: Angsana, Pterocarpus indicus Will, Dormancy.
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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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