Judul: Pengaruh Jarak Tanam dan Pemupukan Terhadap Pertumbuhan dan Produktivitas Tanaman Torbangun (Coleus amboinicus Lour)
Abstrak: This research was conducted to study the effects of plant spacing and fertilizer on the growth and productivity of Torbangun plant (Coleus amboinicus Lour). The experimental design used in this research was t-test for fertilizer manure: poultry (PA) and cattle (PS). This research was done based on completely randomized design (CRD) with 4 plant spacing treatments 0.5 x 0.5 m (J1), 0.5 x 1 m (J2), 1 x 1 m (J3), 1.5 x 1 m (J4). It is shown that poultry manure significantly resulted in better on the growth and productivity compared to that of cattle manure. Plant spacing significantly affected the variables rate of the increasing number of leaves with poultry manure, production number of leaves with poultry manure in the second period, dry weight of Torbangun leaves with cattle manure in the second period. Plant spacing of 1 x 1 m (J3) and 1 x 1.5 m (J4) was the highest on the growth and productivity of Torbangun plant with the application of either 1 kg poultry manure or cattle manure
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Judul: Pertumbuhan dan Produksi Daun Torbangun (Plectranthus amboinicus Spreng.) dengan Pemupukan Organik dan Pemangkasan
Abstrak: Torbangun is a nutritious crop that increase breast milk because it contains lactagogen. Most study of torbangun plants focuses on pharmacological characteristics of plant. There is a need for research in cultivation techniques using organic fertilizer and pruning. The purpose of this study was to investigate the effect of organic fertilizer and pruning on the growth and leaf production of torbangun plant. This study used randomized block design (RBD) in the first experiment with fertilizer factor and Split plot design in the second experiment with fertilizer and pruning. Both of the experiment used Tukey‟s (Honestly Significant Difference) test. Organic fertilization is divided into 5 levels: without fertilizer, cow manure+rock phosphate, cow manure+rice-hull ash, rock phosphate+rice-hull ash, and cow manure+rock phosphate+rice-hull ash. Pruning is consisted of 2 levels: without pruning and with pruning. The results showed that fertilization using cow manure + rock phosphate + rice-hull ash increased shoot fresh weight of 125.21% compared to without fertilization. Pruning reduced plant biomass and leaf number. Torbangun growth is slow, so harvesting should have been done in a longer interval.
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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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