Judul: Structure and Composition of Shorea pinanga Stands in the KHDTK Haurbentes, Bogor
Abstrak: Hutan tanaman shorea pinanga di luar habitat sudah ditanam sejak 1940 di KHDTK Haurbentes, Bogor. Seperti apakah regenerasi alami dan struktur tegakan yang terjadi di kawasan tersebut. Tujuan penelitian adalah menganalisis proses regenerasi alami pada tegakan S. pinanga. Penelitian menggunakan metode analisis vegetasi di lima petak penelitian yaitu petak 11, 12, 68, 72, dan 100 dengan masing-masing petak dibuat dua plot pengamatan. Hasil penelitian menunjukkan bahwa hutan tanaman S. pinanga berumur tua telah membentuk struktur tegakan seperti hutan alam dengan bentuk kurva “J terbalik”. Permudaan alami S. pinanga ditemukan di semua petak penelitian. Petak 11, 68 dan 72 diperoleh kemiripan struktur tegakan S. pinanga untuk tingkat semai dan pohon., Shorea pinanga out-of-habitat plantations have been planted since 1940 at KHDTK Haurbentes, Bogor. What is the natural regeneration and stand structure that occurs in the area. The research objective was to analyze the natural regeneration process in S. pinanga stands. The research used the vegetation analysis method in five research plots, namely plots 11, 12, 68, 72, and 100 with each plot made two observation plots. The results showed that old-growth S. pinanga plantations have formed a stand structure similar to natural forests with an "inverted J" curve. Natural sprouts of S. pinanga were found in all study plots. Plots 11, 68 and 72 were similar to S. pinanga stand structure at seedling and tree levels.
Keyword: Hutan tanaman, Shorea pinanga, struktur tegakan, regenerasi alami

Judul: Komposisi Jenis dan Struktur Tegakan Shorea stenoptera Burck di Areal KHDTK Haurbentes, Kabupaten Bogor, Jawa Barat
Abstrak: Luasan hutan di Indonesia yang semakin berkurang akibat deforestasi memerlukan pengelolaan hutan lestari. Shorea stenoptera Burck merupakan salah satu jenis endemik tanaman kehutanan di Borneo. IUCN menyatakan bahwa jenis tersebut termasuk ke dalam status hampir terancam (Near Threatened). Tujuan penelitian ini adalah menganalisis komposisi jenis, struktur tegakan, dan regenerasi alami tegakan S. stenoptera, serta mengidentifikasi pengaruh aspek biofisik terhadap keragaan regenerasi alami S. stenoptera di KHDTK Haurbentes, Kabupaten Bogor, Jawa Barat. Metode yang digunakan adalah analisis vegetasi dengan membangun petak pengamatan sebanyak 5 petak. Hasil penelitian menunjukkan bahwa jenis S. stenoptera mendominasi pada setiap tingkat pertumbuhan pada petak pengamatan S. stenoptera. Struktur tegakan menunjukkan kurva J terbalik. Hal tersebut mengindikasikan tegakan S. stenoptera mengalami perubahan formasi ke hutan alam. Regenerasi S. stenoptera menunjukkan regenerasi normal dengan kerapatan individu semakin berkurang seiring bertambahnya kelas diameter. Aspek biofisik seperti kelerengan dan elevasi sangat memengaruhi pertumbuhan S. stenoptera., The decrease of forest areas in Indonesia because of deforestation need sustainable forest management. Shorea stenoptera Burck is native forest species in Borneo. IUCN declare this species included in Near Threatened. This research aims to analyze species composition, stand structure and natural regeneration of Shorea stenoptera Burck, also identify the biophysics effect on the regeneration performance of S. stenoptera in KHDTK Haurbentes. This research methods is using vegetation analysis by constructing five observation areas. The results thats S. stenoptera dominating in every growth level in S. stenoptera observation area. Stand structure showing inverse J curve. Thats indicates S. stenoptera stand have changed to nature forest. S. stenoptera regeneration showing normal regeneration with density decreased along diameter class increased. Biophysics aspect like slope and elevation effects the S. stenoptera growth.
Keyword: biophysics, natural forest, regeneration

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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