Judul: Potential Estimation of Aren (Arenga pinnata (Wurmb) Merr.) in Cimantaja Resort, Mount Halimun Salak National Park
Abstrak: Aren memiliki kelimpahan yang dapat dijumpai di kawasan Resort Cimantaja, dimana seluruh tegakan yang ada di Resort Cimantaja merupakan tegakan yang tumbuh secara alami/liar, tanpa adanya kegiatan penanaman atau budidaya. Tujuan dari penelitian ini adalah untuk mengestimasi potensi tegakan aren terhadap regenerasi dan produktivitasnya, mengidentifikasi pola akses masyarakat dalam pemanfaatan aren, serta menganalisis saluran pemasaran gula aren. Metode yang digunakan dalam menduga potensi adalah wawancara dan inventarisasi tegakan. Hasil penelitian ini menunjukkan bahwa potensi tegakan dari tingkat tiang dan pohon belum menghasilkan cukup besar dengan persentase 84% merupakan pohon produktif. Pada inventarisasi tegakan, tingkat regenerasi menurun dari tingkat semai hingga pohon dengan kategori lestari. Produktivitas tegakan ditinjau dari kelas umur dan waktu, total potensi gula aren dari 4 desa yang terbesar adalah pada kelas umur 12-15 tahun sebesar 100.933 kg/tahun dengan jumlah 189 pohon, namun total produksi dari rentang umur 8-11 tahun memiliki persentase 56% dari total produksi. Akses pemanfaatan dilakukan di dalam dan di luar kawasan yang berdasarkan lahan garap dan status hak milik. Saluran tataniaga gula aren yang diwakili oleh Desa Cikarae Thoyybah yang menunjukkan bahwa saluran langsung (tingkat 0) memberikan keuntungan yang maksimal bagi petani. Kesimpulan dari penelitian ini adalah kelimpahan aren di Resort Cimantaja ini memiliki potensi jumlah, regenerasi serta produktivitas yang cukup baik dengan akses pemanfaatan yang telah diatur sesuai dengan tempat tumbuh tegakan serta saluran tataniaga yang cukup efisien yang ditunjukan dengan adanya saluran yang melibatkan pengumpul., Aren has an abundance that can be found in the Cimantaja Resort area, where all stands in the Cimantaja Resort are stands that grow naturally/wildly, without any planting or cultivation activities. The objectives of this study were to estimate the potential of aren stands for regeneration and productivity, identify regeneration access patterns in the use of aren, and analyze the marketing distribution of aren sugar. The methods used in estimating the potential were interviews and inventory of stands. The results of this study show that the potential of stands from the stake and immature tree levels is sufficiently large with a percentage of 84% being productive trees. In the stand inventory, the regeneration rate decreased from seedling to tree level with a sustainable category. Stand productivity in terms of age class and time, the total potential of palm sugar from 4 villages is the largest in the age class of 12-15 years at 100,933 kg/year with 189 trees, but the total production from the age range of 8-11 years has a percentage of 56% of the total production. Access to utilization based on cultivated land and private status is inside and outside the area. The palm sugar trade chain represented by Cikarae Thoyybah Village shows that the direct chain (level 0) provides maximum profit for farmers. The conclusion of this study is that the abundance of aren in Cimantaja Resort has the potential for number, regeneration and productivity that is sufficient, with access to utilization that has been regulated according to the place of growth of the stand and a sufficiently efficient trade chain that is shown by the involvement of middlemen.
Keyword: aren, pemanfaatan, potensial, produktivitas, tataniaga

Judul: Potential and Utilization of Aren (Arenga pinnata (Wurmb) Merr.) in the Buffer Village of Gunung Rinjani National Park
Abstrak: Aren (Arenga pinnata (Wurmb) Merr.) merupakan tumbuhan multiguna yang memiliki potensi nilai ekonomi dan ekologi yang tinggi. Masyarakat sekitar Taman Nasional Gunung Rinjani banyak yang melakukan kegiatan perekonomian berasal dari hasil tumbuhan aren. Penelitian ini bertujuan mengidentifikasi potensi populasi aren dan bentuk pemanfaatan aren di desa penyangga Taman Nasional Gunung Rinjani. Pengambilan data dilakukan melalui studi literatur, wawancara semi terstruktur dengan metode purposive sampling, observasi lapang, dan analisis vegetasi. Pemanfaatan paling besar terdapat pada bagian bunga jantan untuk penyadapan air nira sebagai bahan baku pembuatan gula aren. Pemanfaatan lain yang dilakukan oleh masyarakat adalah bagian bunga betina untuk menghasilkan kolang-kaling; ijuk untuk pembuatan sapu dan atap rumah; daun untuk pembungkus makanan, pembuatan sapu lidi, dan pembatas lahan; batang mudanya sebagai bahan makanan; serta batang tuanya untuk pembuatan gagang perkakas dan pembatas lahan. Populasi tumbuhan aren di sekitar Taman Nasional Gunung Rinjani termasuk kedalam kategori lestari. Perlu adanya kerjasama antar berbagai pihak dalam pemanfaatan aren untuk meningkatkan nilai komoditas aren., Sugar palm (Arenga pinnata (Wurmb) Merr.) is a multipurpose plant that has high potential economic and ecological value. Many people around the Gunung Rinjani National Park carry out economic activities derived from sugar palm products. This study aims to identify the potential of the sugar palm population and the form of sugar palm utilization in the buffer area of Gunung Rinjani National Park. Data were collected through literature study, semi-structured interviews with purposive sampling method, field observations, and vegetation analysis. The greatest utilization is found in the male flowers portion for tapping the water of nira as a raw material for making palm sugar. Another parts of sugar palm commonly utilized is the female flowers to produce kolang-kaling; fibers used to make brooms and roofs; leaves used to make broomsticks, wrapping food, and land dividers; young stems as food; as well as old trunk for the manufacture of tool handles and land dividers. The sugar palm population around Mount Rinjani National Park is included in the sustainable category. Cooperation between various parties is needed in the use of sugar palm to increase the value of sugar palm commodities.
Keyword: sugar palm, potential, utilization

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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