Judul: Penentuan Sistem Silvikultur Berbasis pada Proses Pemulihan Vegetasi dalam Teknik Silvikultur Intensif (Studi Kasus di Areal PT Sarpatim, Kalimantan Tengah)
Abstrak: Mistakes in implementing the right silvicultural system with forest characteristic cause forest degradation. The aim of this observation is to determine the appropriate silvicultural system based on the forest standing structure and similarity of community. The analyzed data’s composition’s type and forest standing structure, forest regeneration type composition, type variety index value, ordination showed by important value index and community dissimilarity index, and cluster and biplot analysis. The result shows that non-Dipterocarpaceae commercial type community has the biggest density and proportion in all levels. Forest standing structure shapes J-reversed curve. The variety on all plots is high enough. Ubar and red meranti dominate all observation plots. Almost tree community has relatively different types in each plot. Regeneration community almost all has value for ID <50% that means the community is relatively the same. It can be seen from cluster analysis chart which part of three grup. The biplot analysis result shows that TJ6 has the most similarity between recovery and tree, while the other plots have different composition.
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Judul: Komposisi Functional Species Group pada Sistem Silvikultur Tebang Pilih Tanam Jalur di Area IUPHHK-HA PT Sarpatim, Kalimantan Tengah
Abstrak: Forest management can have an impact on changes in forest structure and composition of plant species. Functional species Group (FSG) may explain the unity of the trees species that are selected in a group in a forest management activities so that it can help in explaining the characteristic of biodiversity such as the quality of habitat and ecosystem processes. The purpose of this research is to know the composition of forest vegetation that the production system are managed with a Silvikultur system of TPTJ as seen from the forest structure and composition of the type that belongs to FSG for the stands and natural regeneration in log over area (LOA) and KPPN (The Conservation of Germplasm Area) IUPHHK-HA PT Sarmiento Parakantja Timber (Sarpatim), Central Kalimantan. Analysis of the composition of the stands type and structure used terraced path in the area of TPTJ and KPPN. The results showed that the types of climax on an entire swath of observations, generally have greater proportion than the group of pioneers, the number of the climax type is 100 while pioneer type is 59. The structure of the stands form a J reverse curve, it show that the composition of vegetation recovery on log over areas managed by using TPTJ and KPPN Silvikultur system has balance characteristic of uneven age forest. The value of diversity is high (H'>3). Most of tree and stands community have different communities (ID>50%).
Keyword: Bogor Agricultural University (IPB), composition of species, Forest management, Silviculture system

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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