Judul: Potency and Effect of Organic Bio-fertilizer on Aren (Arenga pinnata Merr.) Stands in Sungkap Village, Central Bangka Regency
Abstrak: Aren memiliki nilai ekonomis dan ekologis tinggi karena hampir semua bagiannya dapat dimanfaatkan. Potensi aren cukup menjanjikan karena dapat hidup di berbagai kondisi tanah asalkan tercukupinya unsur hara. Penelitian bertujuan menduga potensi tegakan aren, produksi nira, pengaruh pupuk terhadap tegakan aren, dan rencana pengembangan aren di Desa Sungkap. Penelitian dilakukan dengan pemberian pupuk organik hayati merek Pupuk Ghaly Organik IPB dengan 45 sampel aren dan diuji dengan ANOVA. Hasil menunjukkan aren di Desa Sungkap menyebar di lahan budidaya dan liar yang keduanya menyebar secara berkelompok. Produksi nira yang tertinggi terjadi di lahan liar. Indikator tumbuhan dengan pemupukan seperti tinggi batang, lilit batang, jumlah daun, dan produksi nira terjadi secara signifikan, sedangkan pH dan brix nira tidak signifikan. Tutupan lahan kebun campuran diasumsikan sebagai habitat aren yang potensial, namun potensi tegakan aren masih belum optimal, sehingga perlu dilakukan budidaya dengan sistem agroforestri. Hasil penelitian dapat digunakan sebagai acuan dalam menduga potensi tegakan dan pengaruh pemupukan terhadap tegakan aren., Sugar palm has high economic and ecological value as almost all of its parts can be utilized. The potential of sugar palm in Sungkap Village is promising because it can thrive in various soil conditions as long as there is sufficient nutrient supply. The research aims to estimate the potential of sugar palm stands, sap production, the influence of fertilizer on sugar palm stands, and development plans for sugar palm in Sungkap Village. The research was conducted by applying organic bio-fertilizer branded Ghaly Organik IPB fertilizer to 45 samples of sugar palm and tested using ANOVA. The results indicate that sugar palm in Sungkap Village are distributed in both cultivated and wild areas, both of which are clustered. The highest sap production occurs in wild areas due to its habitat habitat. The highest sap production occurs in wild land. Plant indicators affected by fertilization such as trunk height, trunk girth, number of leaves, and sap production show significant changes, while pH and brix indicators do not. Mixed garden land cover is assumed to be a potential habitat, but the potential of sugar palm stands is still not optimal, thus cultivation with agroforestry systems are needed. The research results can be used as a reference for assessing the potential of stands and the effects of fertilization on sugar palm stands.
Keyword: budidaya, liar, potensi, pupuk, tegakan

Judul: Stand Potential  Aren (Arenga pinnata Merr.) in Beruas and Teru Villages, Central Bangka Regency
Abstrak: Aren merupakan tumbuhan palma dari famili Arecaceae yang memiliki banyak manfaat dan bernilai ekonomi bagi masyarakat Desa Beruas dan Teru. Pemanfaatan aren bergantung pada aren yang tumbuh liar sehingga tingkat produksi aren rendah. Tujuan penelitian untuk menduga potensi tegakan dan produksi nira aren dan menyusun rencana pengembangan aren. Pengambilan data dilakukan dengan studi literatur, analisis vegetasi, pengamatan lapang, dan wawancara. Data dianalisis secara deskripsi kualitatif dan kuantitatif meliputi pendugaan tegakan aren, pola sebaran, kategori kelestarian, produksi nira aren, dan rencana pengembangan tegakan aren. Penelitian menemukan bahwa Desa Beruas memiliki 252 pohon aren dengan klasifikasi kelestarian fair, sementara Desa Teru memiliki 116 pohon dengan kelestarian good. Pola persebarannya cenderung mengelompok. Rata-rata produksi nira aren di Desa Beruas mencapai 11,38 liter per pohon per hari, sementara di Desa Teru belum ada tegakan yang menghasilkan nira aren. Pengembangan agroforestri dapat dilakukan di Desa Beruas, tetapi tidak memungkinkan di Desa Teru karena kondisi tempat tumbuhnya tidak sesuai., Aren is a palm plant from the Arecaceae family that has many benefits and economic value for the people of Beruas and Teru villages. Aren utilization depends on wild-growing aren palm so that the level of aren palm production is low. The aim of the study was to estimate the potential of aren palm stands, the production of aren palm sap, and to compose the development plan of aren palm. Data were collected through literature study, vegetation analysis, field observation, and interview. Data were analyzed qualitatively and quantitatively including estimation of palm stands, distribution patterns, sustainability categories, palm juice production, and development plans for palm stands. The study found that Beruas village has 252 aren palm trees with fair sustainability classification, while Teru village has 116 trees with good sustainability. The distribution pattern tends to be clustered. The average production of palm sap in Beruas village reached 11.38 liters per tree per day, while in Teru village there were no stands producing palm sap. Agroforestry development is possible in Beruas village, but not in Teru village due to the unsuitable growing conditions.
Keyword: aren, nira, pola sebaran, potensi

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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