Judul: Produksi Pucuk dan Kadar Metabolit Bangun-Bangun (Plectranthus amboinicus (Lour.) Spreng) dengan Pemupukan Organik dan Pemangkasan.
Abstrak: Bangun-bangun (Plectranthus amboinicus (Lour.) Spreng) has been used as breast milk stimulant (Lactagogue) by Bataknese people (especially mothers after childbirth) in Indonesia for hundreds of years. Bangun-bangun contains secondary metabolite i.e. polyphenol, saponin, glycoside, aromatic compounds, flavonoid and phenolic. No information was found on the effect of organic fertilizing and pruning on shoot production and metabolite content of bangunbangun therefore, the research about organic fertilizing and pruning were needed on shoot production and metabolite content of bangun-bangun to get standar operasional procedure (SOP) crop management of bangun-bangun. The objectives of the research was to investigate the effect of organic fertilizing and pruning on shoot production and metabolite compounds of bangun-bangun. Two field experiments had been conducted at the IPB experimental station (Bogor, Indonesia), under the shade of coffee tree with shade percentage of ± 35%. The first experiment was conducted in December 2012 – February 2012, whereas the second experiment was in March – May 2013. The first experiment was the first harvest cycle before pruning, whereas the second experiment was the second harvest cycle after pruning. The first experiment used three types of organic fertilizer i.e. cow manure (CM), rock phosphate (RP), and rice-hull ash (RH) (rate ha-1 for each treatment : 0 + 0 + 0; 12.3 t CM + 1.5 t RP + 0 RH; 12.3 t CM + 0 RP + 5.5 t RH; 0 CM + 1.5 t RP + 5.5 t RH; and 12.3 t PK + 1.5 t RP + 5.5 t RH. Each treatment was repeated three times. The second experiment was laid out in split plot design and the main plot was organic fertilizer, whereas sub plot was pruning. Pruning treatment was without pruning and pruning 25 cm above ground. Each treatment was repeated three times. The result showed that (1) Application of organic fertilizer resulted higher plant nutrient content (N, P, and K) than control, (2) Without harvesting, bangunbangun had slower growth than control, (3) Application of organic fertilizer without pruning gave higher growth and shoot production than control, (4) The decreased of rain intensity increased metabolite content, (5) Application of complete organic fertilizer gave higher metabolite production than control, (6) Pruning decreased metabolite content, (7) Bangun-bangun need to be fertilized organically and should not be pruned.
Keyword: Plectranthus amboinicus (Lour.) Spreng, secondary metabolite, phenylalanine ammonia lyase,, phenolic, anthocyanin

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.
Keyword: 

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.
Keyword: