Judul: Peningkatan Mutu Bibit Torbangun (Plecranthus amboinicus Spreng.) dengan Pemilihan Asal dan Pemberian Auksin
Abstrak: Torbangun is an indigenous vegetable that its leaves used as herbal plant. Torbangun propagation still done vegetatively by cutting, but it has not been developed. The purpose of this research is to get the best combination part of stem cuttings and auxin concentration, in order to achieve vigor cutting. This research was conducted at Conservation and Biopharmaca Cultivation, Cikabayan IPB, Bogor from January until March 2014. This research consisted of 2 experiments. The first experiment treatments were part of stem cuttings torbangun (tips, central and base) and auxin concentrations (0, 20 and 40 ppm). Second experiment treatments were length of tips cuttings torbangun (3.5, 7, and 10.5 cm) and auxin concentration (0, 20, dan 40 ppm). Because of limited seed, tips cuttings at first experiment was same with tips cuttings with 7 cm length at second experimment. There were 15 combination of treatments, 3 replications and each treatment consisted of 10 cuttings, in this way a total was 450 cuttings. The experiments was laid out in Randomized Completely Block Design – Factorial with two factor. The result of this experiments showed that tips was the best part of stem cuttings to achieve vigor cutting torbangun. All concentrated of auxin until 40 ppm did not affect to cutting’s indicator. 10.5 cm of length tips cuttings was the best to increase long roots and nodes of torbangun
Keyword: seed quality, Plectranthus amboinicus, indigenous, cutting methods

Judul: Increased Yield of Torbangun Plant (Coleus amboinicus Lour.) by Giving Auxins and Various Bioactivators Treatment
Abstrak: Perbanyakan torbangun (Coleus ambinicus Lour.) dilakukan dengan menggunakan stek batang. Penelitian ini bertujuan untuk mempelajari peranan auksin dan bioaktivator sebagai mikroorganisme positif yang mampu meningkatkan produksi tanaman. Penelitian dilaksanakan di Cipanas, Kabupaten Cianjur, Jawa Barat. Percobaan dilaksanakan menggunakan rancangan kelompok lengkap teracak (RKLT) dengan dua faktor. Faktor pertama penelitian ini mengunakan Auksin (IAA yang dilarutkan menggunakan NaOH) dengan dosis 100 ppm. Faktor kedua variasi bioaktivator menggunakan EM4, PGPR, Trichoderma sp., dan asam laktat dengan dosis 10 ml/L. Percobaan terdiri dari 30 satuan percobaan dengan 600 tanaman dan 180 tanaman sampel. Hasil sidik ragam beberapa parameter seperti bobot daun layak jual, bobot daun tidak layak jual, bobot batang dan bobot panen total pada panen 4 menunjukkan adanya pengaruh yang berbeda nyata dari percobaan menggunakan auksin.
Keyword: pemanenan, Perbanyakan torbangun, sidik ragam

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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