Judul: Kajian Permudaan Tumbuhan Langka Kulim (Scorodocarpus borneensis Becc.) dan Komposisi Vegetasi Pohon Sekitarnya di Taman Nasional Tesso Nilo, Riau
Abstrak: Kulim (Scorodocarpus borneensis Becc.) is one of Indonesia wood species which have high economic value. This species is widely used by people in Bagan Siapi-api the Province of Riau for ship and building materials (Ismail 2000). Kulim is categorized as strong and long lasting wood. Unfortunately, this species of wood is rare to be found in the nature due to habitat disturbance. The aims of this research are to the population condition identify, the young level of kulim, the structure and composition of vegetations surround kulim‟s natural habitat. The vegetation data was collected through plot sampling using combination between strip and quadrate sampling techniques (20 m x 500 m). The total of transec was 5 and it was allocated systematically at every 100 m far from the location kulim found. Trees analysis was undertaken in 20m x 20m of square in every line, at the pole 10m x 10m, at the sapling 5m x 5m and the seedling 2m x 2m. The total of sampling units were 125 plots. The crown stratification was made through drawing 20 m x 100 m line. The data then was analyzed descriptively and quantitatively using vegetation analysis formulas. The formulas were aimed to get Important Value Index (IVI), Evennes Index and Diversity Index. Kulim has density at seedling level of 180 ind / ha, at saplings 35 ind / ha, at the pole 8 ind / ha, while the value at the tree level 2 ind / ha. High amount of Kulim found in diameter classes <10 cm of 20 individuals. It has been found as many as 28 species of tree-level, 24 species on the pole and stake, and 21 in 14 species of seedlings. Middle species diversity index value of 2.95 obtained, whereas equitable distribution of the species seen from the index value close to 1. There are A and B strata header with average height ranges from 20-40 meters. Kulim has strata header with average height ranges from 15-20 meters. Based on this research, Kulim population in TNTN heading to extinction. It‟s caused by the uncontrolled logging in the past. It can be seen by the number of logged-over Kulim‟s stump on this area. It‟s reasonable that Vegetation structure in Kulim habitats dominated by stands of young trees with average stem diameters ranging from 20-30 cm. there is low composition of habitus on research plots that only contain 32 species of tree composition.
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Judul: Species Composition and Vegetation Structure of  Lowland Forest in Pulau Rambut Wildlife Reserve, Kepulauan Seribu, DKI  Jakarta
Abstrak: Hutan dataran rendah perlu diteliti struktur dan komposisinya karena memiliki keanekaragaman hayati yang tinggi. Analisis vegetasi ditujukan untuk mengetahui komposisi jenis dan struktur vegetasi hutan dataran rendah Suaka Margasatwa Pulau Rambut. Analisis vegetasi dilakukan dengan metode jalur dan garis berpetak dengan luasan yang diamati sebesar 20.000 m2 dengan jumlah jalur pengamatan 10 jalur dengan ukuran 20 m x100 m. Data vegetasi yang diperoleh diolah untuk mendapatkan Indeks Nilai Penting (INP), Indeks Keanekaragaman Jenis Tumbuhan, Indeks Dominansi Jenis, Indeks Kekayaan Jenis dan Indeks Kemerataan Jenis. Pengambilan data abiotik seperti intensitas cahaya, ketinggian, kelerengan, suhu basah dan kering, kelembaban relatif, pH tanah, Kapasitas Tukar Kation tanah, dan tekstur tanah. Tumbuhan penyusun di lokasi penelitian terdapat 15 jenis. Kedoya mendominasi pada tingkat pohon, mengkudu mendominasi pada tingkat tiang, jeruk kingkit mendominasi pada tingkat pancang, dan kedoya medominasi pada tingkat semai. Nilai kerapatan tertinggi terdapat pada tingkat pertumbuhan semai sebesar 900500 individu ha-1 sehingga menghasilkan kurva “J” terbalik baik dalam struktur vertikal maupun horizontal.
Keyword: Faktor Abiotik, Indeks Nilai Penting, Komposisi Jenis, Struktur Vegetasi, Abiotic factor, importance value index, lowland forest, species composition, vegetation structure

Judul: Penyelesaian Masalah Rotasi Aliran Fluida Kental Von Karman Menggunakan Metode Homotopi
Abstrak: Von Karman equation is an equation that describes fluid viscous flow induced by infinite disk rotation. By assuming steady flow and laminar, viscous incompressible fluid flow is represented in Von Karman equation by an angular velocity and the vertical direction velocity as the independent variables. Von Karman equation is a nonlinear problem that is solved using the homotopy method. The use of homotopy method is done by defining an homotopy function that requires auxiliary parameters to control the convergent region of the solution. The solution is a recursive formula with given initial conditions. Using software based-functional shows that velocity components converge to a value.
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