Judul: Pengaruh Tanaman Penutup Tanah terhadap Pertumbuhan Bibit Jabon Merah (Anthocephalus macrophyllus (Roxb.) Havil.) di Persemaian
Abstrak: Cover crop is a plant that is used to control erotion on open land, such as ex-mining land. Recently, some of cover crops that available are Centrosema pubescens, Calopogonium mucunoides, Pueraria javanica, and Mucuna sp. In the generally, they are creeped and enlaced so they should be controlled intensively. Therefore it is needed to look for alternative types of cover crops, that does not disturb another plants. The aim of this research are get information about the influence of legumes cover crop and grass to the growth of red jabon, and get information about growing speed of cover crop. Based on the analysis of variance in all red jabon parameters, showed that planting red jabon with cover crop in the same polybag do not reduce of red jabon growth. Cover crop who has life ability, covered open area ability quickly, and include to the potential species is Desmodium. Desmodium has the highest percentage of life about 72%, better in the length of primary stem and total of branch than Arachis and Paspalum
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Judul: Developments of Desmodium spp. as cover crop plant in post mining reclamation.
Abstrak: Mining is one of state revenue source in Indonesia. The topsoil were deployed after the excavation of minerals that usually not form a compact structure, so it is prone to erosion when it rains. One effort to reduce the rate of soil ground erosion is planting cover crops. Cover crops are specifically planted to protect soil from erosion threat of damage and to improve the chemical and physical properties of soil. The Objective of this study is to obtain information about taxonomy and characteristics of cover crop of Desmodium spp. type, to calculate the productivity of cover crop of Desmodium spp. types, and to analyse the response of jabon (Anthocephalus cadamba) seedlings growth to soil cover crops Desmodium spp. This research was conducted in three stages, the first stage is multiplication Desmodium spp. and observation on its characteristic, second is planting in the nursery to measure the rate of plant growth and productivity, and the lastly is planting Desmodium spp. with jabon seedling to observe its effects on jabon seedling. The research data is analyzed with statistics to observe the effect of its treatment and treatment combination of growth parameters of jabon seedling, if significant then further tested DMRT (Duncan's Multiple Range Test) with a 5% significance level. Study results shows that Desmodium spp. plant has different characteristics among species. D. heterophyllum type is the highest type of its individual accretion compared with D. ovalifolium and D. triflorum. Desmodium spp. plant have different productivity among species. D. heterophyllum type has the highest productivity compared with other types, where the speed of land cover, plant growth rate, and the highest biomass production compared with D. ovalifolium and D. triflorum. Treatment interaction of Desmodium spp. with soil type can increase the diameter, height, number of leaves of jabon seedlings with the greatest sequence is planting with D. triflorum, D. heterophyllum, D. ovalifolium, and control, so that it can recommended to be planted together.
Keyword: Anthocephalus cadamba, plant growth rate, soil ground erosion, Jabon seedling

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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