Judul: Study of White Jabon (Anthocephalus cadamba) Growth in Gap Planting Research Plot PT. Sarmiento Parakantja Timber, Central Kalimantan
Abstrak: Sistem silvikultur Tanam Rumpang Tebang Rumpang (TRTR) diharapkan menjadi salah satu sistem silvikultur untuk merehabilitasi hutan alam terdegradasi. Penelitian ini bertujuan mengetahui pertumbuhan jabon putih yang ditanam dalam rumpang serta mengetahui pengaruh kemiringan lapangan terhadap pertumbuhan jabon putih. Metode penelitian menggunakan cara sensus dan pengukuran diameter dan tinggi total pohon jabon putih yang terdapat dalam 16 buah rumpang dengan luas masing-masing rumpang 2000 m^2. Hasil penelitian menunjukkan bahwa ukuran diameter berumur dua tahun adalah 7,42 cm dan tinggi total pohon rata-rata mencapai 651,11 cm. Uji statistik menunjukkan terdapat perbedaan nyata pengaruh kelerengan dengan jabon putih. Jabon putih tumbuh lebih baik pada kelas lereng curam dibandingkan dengan kelas lereng datar -landai dan sedang., The Gap Planting and Gap Cutting silvicultural system (TRTR) is expected to be one of the silvicultural systems to rehabilitate degraded natural forests. This study aims to determine the growth of white jabon planted in gaps and to determine the effect of slope on the growth of white jabon. The research method used the census and measured the diameter and total height of the white jabon trees contained in 16 gap plots of stump with an area of 2000 m^2 each. The results showed that the diameter at two years old was 7,42 cm and the average total height of the trees was 651,11 cm. Statistical tests showed that there were significant differences in the effect of slopes on white jabon growth. White Jabon grows better on steep slopes compared to flat-sloping and moderate slopes.
Keyword: Anthocephalus cadamba, forest degradation, gap planting, growth

Judul: Growth of White Jabon (Anthocephalus cadamba) in The  Gap Planting Research Area at PT. Sarmiento Parakantja Timber, Central  Kalimantan
Abstrak: Sistem silvikultur Tanam Rumpang dan Tebang Rumpang (TRTR) diharapkan dapat meningkatkan produktivitas hutan alam yang mengalami degradasi. Jabon putih yang ditanam pada areal rumpang merupakan salah satu jenis yang potensial untuk dikembangkan dalam sistem TRTR karena pertumbuhannya yang sangat cepat. Penelitian ini bertujuan untuk menganalisis pertumbuhan jabon putih dalam rumpang dan pengaruh kelerengan terhadap pertumbuhan jabon putih. Penelitian dilakukan pada bulan Maret hingga Mei 2022. Kegiatan pengambilan data pertumbuhan jabon putih dilakukan di areal tanam rumpang dengan topografi datar-curam (0% - 40%). Hasil penelitian menunjukkan Jabon putih yang ditanam dalam rumpang memiliki rata-rata pertumbuhan diameter dan tinggi jabon putih yaitu sebesar 3.87 cm/thn dan 215.49 cm/thn. Uji statistik menunjukkan terdapat perbedaan nyata pengaruh kelerengan terhadap pertumbuhan diameter pohon jabon putih, The silvicultural system of gap planting and gap clear cutting (TRTR) is expected to increase the productivity of degraded natural forests. White jabon which is planted in the gap area is one of the species that potentially developed in the TRTR system due to its very fast growth characteristics. This study aims to analyze white jabon growth in the gap area and the effect of slope on it. The study was conducted from March to June 2022. The data collection was carried out in the gap planting area with flat to steep topography (0 - 40%). The results showed that white jabon planted in gap planting area had an average diameter and height growth of 3.87 cm/year and 215.49 cm/year. Statistical tests showed a significant difference in the effect of slope on diameter growth of white jabon.
Keyword: Anthocephalus cadamba, forest degradation, gap planting, growth

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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