Judul: The Use of Stimulants in Tapping Pine Resin in Age  Classes V and VI at BKPH Paninggaran, East Pekalongan
Abstrak: Bagian Kesatuan Pemangkuan Hutan (BKPH) Paninggaran termasuk dalam kelas perusahaan pinus, di mana getah pinus menjadi komoditas utamanya. Dengan demikian produktivitas getah pinus sangat diperhatikan. Proses keluarnya getah saat penyadapan umumnya dibantu menggunakan zat perangsang (stimulansia). Dalam penerapannya, BKPH Paninggaran menggunakan stimulansia berbahan organik dan anorganik. Meskipun menggunakan stimulansia berbeda, BKPH Paninggaran belum mengetahui stimulansia mana yang paling efektif dan efisien untuk digunakan. Penelitian ini bertujuan untuk menganalisis produktivitas dan nilai tambah penyadapan getah pinus ketika diberi stimulansia. Metode penelitian menggunakan rancangan acak lengkap dengan faktorial dua faktor. Faktor pertama penggunaan lima jenis stimulansia. Faktor kedua yaitu kelas umur V dan VI. Stimulansia yang menghasilkan produktivitas getah tertinggi adalah stimulansia berbahan aktif etilen dan asam sitrat ditambah 5% asam sulfat dengan rata-rata produktivitas 12,98 g/quarre/hari atau mengalami kenaikan hasil sadapan getah sebesar 76,44 % jika dibandingkan dengan tanpa penggunaan stimulansia (kontrol) 7,36 g/quarre/hari. Produktivitas getah pinus pada kelas umur V dan VI tidak berbeda nyata yaitu sebesar 10,13 g/quarre/hari dan 9,97 g/quarre/hari. Tidak terdapat interaksi antara faktor stimulansia dengan kelas umur. Nilai tambah stimulansia yang paling tinggi terdapat pada stimulansia berbahan aktif etilen dan asam sitrat ditambah 5% asam sulfat sebesar Rp 52,76/quarre/hari., The Forest Management Unit (BKPH) Paninggaran falls under the pine enterprise-class, where pine resin is the main commodity. Consequently, the productivity of pine resin is highly regarded. The process of resin extraction during tapping is generally aided by stimulants. In practice, BKPH Paninggaran uses both organic and inorganic stimulants. Despite using different stimulants, BKPH Paninggaran has yet to determine which stimulant is the most effective and efficient. This study analyzes the productivity and added value of pine resin tapping when applied stimulants. The research method used a completely randomized design with a two-factor factorial. The first factor is the use of five types of stimulants. The second factor is age class V and VI. The stimulant that resulted in the highest resin productivity was the stimulant with active ingredients of ethylene and citric acid plus 5% sulfuric acid, with an average productivity of 12.98 g/quarre/day, representing a 76.44% increase in resin yield compared to the control (7.36 g/quarre/day). The productivity of pine resin in age classes V and VI did not differ significantly, being 10.13 g/quarre/day and 9.97 g/quarre/day, respectively. There was no interaction between the stimulant factor and the age class. The highest added value of the stimulant was found in the stimulant with active ingredients of ethylene and citric acid plus 5% sulfuric acid, amounting to Rp 52.76/quarre/day.
Keyword: Penyadapan, Produktivitas, Getah Pinus, Kelas Umur, Stimulansia

Judul: The Utilization of Stimulant in Pine Sap Tapping at Age Class III and IV in BKPH Paninggaran
Abstrak: Permintaan getah pinus semakin meningkat sehingga dilakukan upaya peningkatan produksi getah dengan penggunaan stimulansia dalam aktivitas penyadapan getah pinus. Stimulansia anorganik dan organik telah lama diterapkan Bagian Kesatuan Pemangkuan Hutan (BKPH) Paninggaran namun belum diketahui produktivitas bahkan untuk kelas umur yang berbeda. Penelitian bertujuan untuk menganalisis produktivitas dan nilai tambah produktivitas getah pinus menggunakan berbagai stimulansia serta tanpa stimulansia (kontrol) pada kelas umur III dan IV. Hasil menunjukkan stimulansia yang menghasilkan produktivitas paling tinggi adalah stimulansia berbahan aktif etilen dan asam sitrat serta 5% H2SO4 untuk kelas umur III sebesar 10,70 g/quarre/hari dengan persentase kenaikan 75,12% terhadap kontrol dan kelas umur IV sebesar 8,47 g/quarre/hari dengan persentase kenaikan 87,46% terhadap kontrol. Penggunaan stimulansia tersebut juga menghasilkan nilai tambah tertinggi sebesar Rp 39,21/quarre/hari sehingga paling optimal untuk diterapkan pada kelas umur III dan IV., The demand for pine resin is increasing, so that efforts are being made to increase sap production by using stimulants in pine sap tapping activities. The inorganic and organic stimulants have long been implemented by the Paninggaran Forest Management Unit (BKPH), but productivity has yet to be discovered, even for different age classes. The research aims to analyze the productivity and added value of pine resin productivity using various stimulants and without stimulants (control) in age classes III and IV. The results show that the stimulant that produces the highest productivity is the stimulant with active ingredients ethylene and citric acid and 5% H2SO4 for age class III at 10,70 g/quarre/day with a percentage increase of 75,12% compared to control and age class IV at 8,47 g/quarre/day with a percentage increase of 87,46% compared to the control. The use of this stimulant also produces the highest added value of IDR 39.21/quarre/day, so it is optimal for application in age classes III and IV.
Keyword: Kelas Umur, Getah Pinus, Stimulansia, biaya stimulansia, produktivitas getah pinus

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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