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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Judul: Kekonsistenan Hamiltonian pada Gerak Gelombang Interfacial
Abstrak: The interfacial wave is an internal wave that occurs at boundary of two layers fluid. It appears because there is difference of mass density between the two layers. The objective of this thesis is to formulate the motion of internal wave with flat base and flat as well as free upper bound surface. The motion equation obtained is a Hamiltonian system. The Hamiltonian in this system is expressed by variable of wave deviation and horizontal component of potential velocity. Under assumption that interfacial wave moves only in one direction, it can be shown that the Hamiltonian depends on the solution of the wave motion equation. The coefficients of the equation depend on the physical characteristics of the two layers of fluid, i.e. thickness and mass density. The numerical results show that Hamiltonian in the system is constant. It is consistent with Hamiltonian characteristic, which does not depend on time.
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Judul: Pengaruh kombinasi zat pengaruh tumbuh dan potongan protocorm like bodies untuk perbanyakan anggrek bulan raksasa (Phalaenopsis gigantea) dengan metode kultur jaringan
Abstrak: Anggrek bulan raksasa (P. gigantea) merupakan salah satu anggrek alam dari Kalimantan. Bunganya berbau harum lembut, tersusun dalam tandan yang keluar dari ketiak daun paling bawah dengan tangkai menjuntai sepanjang 40 cm. Jumlah bunga tiap tandan sekitar 20-30 kuntum dengan garis tengah masing- masing bunga 5 cm bunga berwarna hijau keputihan dengan bintik-bintik dan garis-garis kecil coklat kehitaman yang mekar dalam periode 7-30 hari (Rukmana, 2000). P. gigantea merupakan anggrek langka dengan kategori kritis karena keberadaan populasinya menghadapi resiko kepunahan yang sangat tinggi akibat perubahan dan rusaknya habitat asli P. gigantea. Untuk mencegah kepunahan P. gigantea maka harus diupayakan suatu teknik budidaya yang tepat untuk memperbanyak P. gigantea dengan kualitas yang baik dan dalam waktu yang cepat. Hal ini perlu dilakukan karena secara alami biji anggrek yang terdiri dari embrio dan pelindung embrio (testa) tidak dapat tumbuh apabila tidak bersimbiosis dengan mikoriza. Teknik kultur in vitro adalah salah satu alternatif untuk meningkatkan perkecambahan biji anggrek. Modifikasi media dapat meningkatkan kualitas dan kuantitas P. gigantea. Media yang dimodifikasi dengan zat pengatur tumbuh IBA dan BAP dapat meningkatkan kuantitas P. gigantea yang dikulturkan. Penelitian inı dilaksanakan di Unit Kerja Laboratorium Kultur Jaringan Anggrek Kebun Raya Bogor. Penelitian dilakukan selama enam bulan dari Bulan Februari sampai Juli 2003. ...
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