Judul: Natural regeneration and distribution patterns of pasang (Quercus sundaica Blume) at various heights on Mount Slamet, Baturraden, Central Java
Abstrak: Pasang (Quercus sundaica) merupakan salah satu tanaman dari famili Fagaceae. Penelitian dilakukan untuk mengetahui struktur dan komposisi pohon, pola sebaran, permudaan jenis Q. sundaica, serta hubungan sifat fisik lingkungan dengan jenis pohon Q. sundaica. Pengambilan data dilakukan pada dua jalur yaitu Jalur KRB (Kebun Raya Baturraden) dan Jalur P7 (Pancuran 7) serta pada dua zona yaitu sub-montana dan montana. Analisis data yang digunakan yaitu analisis vegetasi, analisis tanah, serta model linear regresi berganda prosedur stepwise. Hasil penelitian menunjukkan bahwa ditemukan 59 jenis tumbuhan, 29 famili, dan 48 marga. Nilai INP tertinggi jenis Q. sundaica terdapat pada Jalur KRB zona montana dan jalur tersebut memiliki kerapatan yang lebih tinggi dibandingkan dengan Jalur P7. Faktor yang berpengaruh terhadap keberadaan Q. sundaica yaitu kelembaban, pH, kapasitas tukar kation (KTK), P-potesial dan K-potensial. Permudaan alami jenis Q. sundaica memiliki nilai 0 yang menandakan pada tingkatan semai, pancang, dan tiang tidak ditemukan jenis tersebut kecuali pada tingkat pancang di zona montana Jalur P7., Pasang (Q. sundaica) is a plant from the Fagaceae family. The study was conducted to determine the structure and composition of trees, distribution patterns, regeneration of the Q. sundaica species, and the relationship between the physical properties of the environment and the Q. sundaica tree species. Data collection was carried out on two lines, namely KRB Line (Baturraden Botanical Gardens) and P7 Line (Pancuran 7) also in two zones, namely sub-montane and montana. Analysis of the data was used vegetation analysis, soil analysis, and multiple regression linear model stepwise procedure. The results showed that there were 59 species, 29 families, and 48 genera. The highest INP value for the species Q. sundaica was found in KRB Line on montana zone and that line also had a higher density than the P7 line. Factors that affect the presence of Q. sundaica were humidity, pH, cation exchange capacity (CEC), P-potential, and K-potential. Natural regeneration of the species Q. sundaica had a value of 0 which indicates that at the seedling, sapling, and pole levels, this species was not found except at the sapling level of the montana zone on Line P7.
Keyword: distribution zone, growing place, Q. sundaica, spread

Judul: Distribution Pattern, Habitat Characteristics, and Regeneration of Krangean (Litsea cubeba) at Mount Slamet, RPH Baturraden, KPH Banyumas Timur
Abstrak: Krangean (Litsea cubeba) adalah salah satu jenis yang mendiami wilayah Gunung Slamet. Bagian pohon krangean memiliki aroma sitrus sehingga dapat dimanfaatkan sebagai penghasil minyak atsiri yang potensial. Kondisi permudaan pohonnya di alam sulit ditemukan sehingga diperlukan informasi mengenai preferensi ekologi yang tepat guna tujuan budidaya dan konservasi. Tujuan penelitian ini adalah mengidentifikasi komposisi dan struktur tegakan, pola sebaran, karakteristik habitat, dan regenerasi krangean (L. cubeba) di hutan lindung Gunung Slamet. Penelitian ini menggunakan metode analisis vegetasi dengan membuat plot berukuran 30 m × 30 m sebanyak 18 plot yang dibagi menjadi Jalur Baturraden dan Pancuran 7. Hasil penelitian menunjukkan pola persebaran krangean cenderung mengelompok (clump) dan kondisi regenerasi yang buruk karena hanya ditemukan pada tingkat tiang dan pohon. Kondisi habitat L. cubeba di Gunung Slamet berada pada ketinggian 1018-2032 mdpl dengan kelerengan curam hingga sangat curam (30 - 59,10%), suhu mulai 11℃ hingga 22,5℃, dan kelembaban 74 - 92%. Jenis tanah yang teramati adalah jenis tanah latosol dengan kategori pH agak masam. Faktor lingkungan yang diujikan tidak berpengaruh nyata pada luas bidang dasar (LBDS) krangean dengan R2 sebesar 55,37%., Krangean (Litsea cubeba) is one of the species that inhabits the area of Mount Slamet. All parts of the krangean tree have a citrus scent so that it can be used as a potential essential oil producer. The condition of tree regeneration in nature is difficult to find, so information on appropriate ecological preferences for cultivation and conservation purposes is needed. The purpose of this study was to identify the composition and structure of stands, distribution patterns, habitat characteristics, and regeneration of krangean (L. cubeba) in the protected forest of Mount Slamet. This study used a vegetation analysis method by making plots measuring 30 m×30 m as many as 18 plots which are divided into Baturraden and Pancuran 7 route. tree. The habitat conditions of L. cubeba on Mount Slamet is at an altitude of 1018-2032 masl with steep to very steep slopes (30-59,10%), temperatures ranging from 11℃ to 22,5℃, and humidity of 74 - 92%. The type of soil observed was latosol soil with a slightly acidic pH category. The environmental factors tested did not significantly affect the basal area (BA) of the krangean with R2 of 55,37%.
Keyword: distribution pattern, habitat characteristics, krangean (L. cubeba), Mountain Slamet, regeneration

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.
Keyword: