Judul: Kerusakan Batang Pohon Akibat Penyadapan Getah Pinus di KPH Cianjur Perum Perhutani Unit III Jawa Barat dan Banten
Abstrak: Pine resin is one of non-timber forest products that be utilized. Production demand of pine resin is high. To fulfill such demand, increase of production of resin was done by over tapping and the use of inorganic stimulant resulted in damaged trees. The purpose of this study was to determine the level of damage of pine trees due to increase in number of quarres and inorganic stimulants by measuring the moisture content and pH level which were found in the pine trees. The results showed that the moisture content and pH in the tapping-affected timber were lower than those in the unaffected ones. The higher the intensity, the higher the damage for the wood. It could be predicted that pine tree on 2-quarre tapping was 86.26%, higher than that of the 6-quarre tapping which was 66.9%.
Keyword: pine tree, pH, moisture content, damage

Judul: Pengaruh Tingkat Kerusakan Pohon Akibat Penyadapan terhadap Produktivitas Getah Pinus di KPH Cianjur Jawa Barat
Abstrak: Profitability targets of Perum Perhutani for pine resin production tend to increase every year, resulting in overtapping and have a bad impact on the tree stands, lowering the productivity of pine resin. Therefore, the use of drilling method was chosen for tapping. The tapping areas are smaller and the recovery of tapping is relatively short so that tree damage can be minimized. The objective of this study was to get a description of various levels of tree damage and resin productivity, to learn about the effect of tree damage on productivity levels of pine resin and to obtain a model to estimate the relationship between the level damage of pine tree and pine resin productivity. Of the 400 overtapped pine trees, the level of tree damage ranged from 4.11-85.54%, the average was 44.58%, the median was 46.16% and the standard deviation was 17.26%. Resin productivity ranged between 0-4.58 g/tree/day, the average was 0.77 g/ tree/day, the median was 0.54 g/tree/day, the mode was 0.13 g/tree/day and the standard deviation was 0.71 g/tree/day. The higher the damage level caused by resin tapping, the lower the pine resin productivity. Pine resin productivity can be predicted by the tree damage level with the best regression model in this study, that is, using a model of: Y=(1.63697+(-0.10739)X)/(1+(-0.04606)X+(-0.00145)X²)
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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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