Judul: Kerusakan dan Pemulihan Pohon Pinus Akibat Penyadan pada Berbagai Ketinggian Tempat di KPH Kediri
Abstrak: Tingkat kerusakan pohon pinus akibat penyadapan didasarkan pada parameter jumlah sadapan, lebar sadapan, tinggi sadapan dan kedalaman sadapan. Ketinggian tempat tumbuh pohon pinus dapat mempengaruhi pemulihan pada bidang sadapan pinus karena kondisi cuaca, suhu udara dan intensitas sinar matahari di setiap ketinggian berbeda. Penelitian ini bertujuan mengetahui kondisi pohon pinus akibat penyadapan, mengukur persentase pemulihan bidang sadapan pohon pinus dan menganalisis pengaruh ketinggian tempat terhadap pemulihan bidang sadapan. Hasil penelitian menunjukkan rata-rata kerusakan sadapan di setiap ketinggian tidak memenuhi prosedur penyadapan getah pinus yang sudah diterapkan oleh Perhutani kecuali rata-rata ketinggian sadapan. Ketinggian tempat berpengaruh terhadap pemulihan bidang sadapan. Rata-rata persentase pemulihan bidang sadapan yang paling tertinggi terdapat di ketinggian <400 m di atas permukaan laut (mdpl) dengan nilai sebesar 50.40%/sadapan dan rata-rata persentase pemulihan bidang sadapan yang paling terendah terdapat di ketinggian >1.000 mdpl dengan nilai sebesar 36.05%/sadapan., The level of damage to pine trees due to tapping is based on parameters such as the number of taps, the width of the taps, the height of the taps, and the depth of the taps. The altitude at which pine trees grow can affect the recovery of the tapped areas because weather conditions, air temperature, and sunlight intensity vary at different altitudes. This study aims to determine the condition of pine trees due to tapping, measure the percentage of recovery of tapped areas on pine trees, and analyze the influence of altitude on the recovery of tapped areas. The results showed that the average damage from tapping at each altitude did not meet the tapping procedures established by Perhutani, except for the average height of the taps. Altitude affects the recovery of tapped areas. The highest average recovery percentage of tapped areas was found at an altitude of <400 meters above sea level (masl) with a value of 50.40% per tap, while the lowest average recovery percentage of tapped areas was found at an altitude of >1,000 masl with a value of 36.05% per tap.
Keyword: Kerusakan sadapan, Ketinggian tempat, Pemulihan bidang sadapan, Penyadapan, Altitude, Recovery of tapped areas, Tap damage, Tapping

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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