Judul: Deteksi Keracunan Alumunium Jenis Legume Cover Crops pada Tanah Pasca Tambang Batubara di PT. Jorong Barutama Greston, Kalimantan Selatan
Abstrak: One of the main problems on the coal post mining area is the low value of pH, so it cause the solubility of Al (Alumunium) is high and become toxic. Soil analysis is ineffective and inefficient to detect toxic presence due to needs long time and expensive. Therefore needs new breakthrough to detect toxic accurately by apllying Centrosema pubescens, Calopogonium mucunoides, and Pueraria javanica as bioindicator. The aim of this research were to observe LCC performance, to study on tolerant and sensitive LCC species toward various of soil color of coal post mining, and to recommend LCC plants as cover ground or as an indicator of toxic. The result showed that the performance of three LCC species which planted on coal post mining soils were less than control soil. C. pubescens was the most tolerant the others species and could be cover ground. C. mucunoides was the most sensitive than the others species, so it could be used as Al toxic bioindicator.
Keyword: Post coal mining, LCC plants, Alumunium

Judul: Deteksi Dini Keracunan Aluminium Tanaman Bridelia monoica Merr. pada Tanah Pasca Tambang Batu Bara PT. Jorong Barutama Greston Kalimantan Selatan
Abstrak: High solubility of Aluminium (Al) and toxic on post coal mined land can cause low level of growth plant. Soil analysis activity is usually done to ensure toxic existence in order to give the exact treatment before the planting activity, so it can reduce the growth plant failure. However soil analysis activity takes time and costly. It is needed a simple and effective method to detect the existence of Al in the soil. Bridelia monoica is a dominant pioneer tree which grow around mine location. This plant can survive on the dry land with low fertility. This plant has many utility and can easily be found around observed location. It is expected that B. monoica can be used as biologic indicator to know the existence of Al. The aim of this research was to know and determine the B. monoica response to toxic Al existence on the post coal mined land in PT. Jorong Barutama Greston. This research has four treatments, they are four colours of post coal mined soil by using the original soil as control with three repetitions. The observed variables are root length, shape of root, amount of leaf, leaf colour, and dry weight. This research resulted that Al can decrease root length, amount of leaf, and dry weight, along with change of root shape on B. monoica. It can be concluded that B. monoica can be used as biologic indicator of Al toxicity.
Keyword: post coal mined soil, Bridelia monoica, Aluminium

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: