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: Pengaruh tingkat kerusakan pohon akibat penyadapan terhadap produktivitas getah pinus di KPH Cianjur Jawa Barat
Abstrak: Target profitabilitas Perum Perhutani dari produksi getah pinus yang cenderung meningkat setiap tahunnya mengakibatkan penyadapan yang berlebihan dan telah memberikan dampak kerusakan kepada kondisi tegakan pohon pinus sehingga produktivitas getah berkurang. Sehubungan dengan itu, penggunaan metode bor dipilih karena bidang sadap yang dilukai lebih kecil dan pemulihan luka bekas sadapan relatif lebih cepat sehingga kerusakan pohon dapat diminimalkan. Tujuan penelitian ini adalah untuk memperoleh gambaran keragaman tingkat kerusakan pohon dan produktivitas getah pinus, mengetahui pengaruh tingkat kerusakan pohon terhadap produktivitas getah pinus dan memperoleh model penduga hubungan pengaruh tingkat kerusakan pohon dengan produktivitas getah pinus. Dari 400 pohon contoh pinus jenuh sadap, diketahui tingkat kerusakan pohon berkisar antara 4.11-85.54%, rata-rata 44.58%, median 46.16% dan simpangan baku 17.26%. Produktivitas getah berkisar antara 0-4.58 g/pohon/hari, rata-rata 0.77 g/pohon/hari, median 0.54 g/pohon/hari, modus 0.13 g/pohon/hari dan simpangan baku 0.71 g/pohon/hari. Semakin tinggi tingkat kerusakan pohon akibat penyadapan getah, menyebabkan penurunan produktivitas getah pinus. Produktivitas getah pinus dapat diduga oleh tingkat kerusakan pohon melalui model regresi terbaik dalam penelitian ini yaitu model regresi, dst
Keyword: metode bor, getah pinus, tingkat kerusakan pohon, model penduga

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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