Judul: Desain Pengelolaan Pakan Gajah Sumatera (Elephas maximus sumatranus Temminck 1847) di Arboretum PT Arara Abadi Propinsi Riau
Abstrak: Sumatran elephant (Elephas maximus sumatranus Temminck 1847) is one of the sub-species of asian elephant. This species was listed in IUCN red book of endangered status, while CITES categorizes the status of sumatran elephants in groups of Appendix I. Losing a place to live and disconnection of elephants roaming point lead also to the limited food resources. Management activities on a good feed elephants needed in order to overcome problems of lack of feed elephants, which feed on the Arboretum PT Arara Abadi can be fulfilled and ensure the welfare of elephants. Research was conducted at the Arboretum owned by PT Arara Abadi, Riau Province. Research carried out for two months in October to December 2009. Object of the research are eight sumatran elephants. The material used in research is sumatran elephant’s feed natural vegetation in the form of the arboretum. Equipment used, including: map work, scales, the tally sheet, peg, label specimens, machetes or knives, compass, camera, tape recorder, tape meter, rope, paper, large plastic bags, glove, field book, stationery and plant identification books lowland grass species and guide of ferns. Primary data including: the structure and composition of vegetation, species, and plant parts are edible, palatability of feed, biomass feed, the characteristics of the location of food resources and availability of forage elephants and elephant habitat carrying capacity. Secondary data including: bio-ecology, habitat, general condition of study sites, and other information as supporting data. Under plant vegetation data obtained by analysis of vegetation, with a sample plot of 1x1m2, a total of 20 plots. Carrying capacity of the habitat (K) for an elephant is calculated using the equation K= P.pu/C. Plant species which are used as feed by sumatran elephants in the location of observation Arboretum PT Arara Abadi are 12 species. Feed plants in the form of grasses and ferns, which belonging to the family Poaceae, Polypodiaceae, Vitaceae, and Pandanaceae. Parts of plants such as elephant feed is consumed whole part of the plant, the trunk + leaves, and trunk + leaves + flowers. The most preferred plant species (palatable) by sumatran elephants, were sianik/chantel (Sorghum halepense), jampang pait (Paspalum conjugatum), jukut pait (Axonopus compressus) and jukut jampang (Eleusina indica). Based on the results of biomass, the availability of feed, forage in the arboretum wet ton/day/80ha obtained at 10,08. With an elephant needs ton/day/8tail 2,24. Arboretum feed bearing capacity is 21 individuals. Resources of elephant’s feed located in the form of swamp residing along the border river. Things can do for feed management design are management of elephant binding sites, increased protection and security of the feed location of the elephant, and elephant binding rotation system of the good and the preservation of elephant forage in the rainy season.
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Judul: Carrying Capacity Estimation Feed of Sumatran Elephant in Corridor Bukit Tigapuluh Landscape, Jambi
Abstrak: Rapid land use changes, including deforestation and land conversion into human areas, lead to the fragmentation of Sumatran elephant (Elephas maximus sumatranus) habitat. This study aimed to assess food capacity and determine habitat suitability for Sumatra elephants in Datuk Gedang Wildlife Corridor Bukit Tigapuluh Landscape. The research was conducted from January to May 2023. Data on potential, productivity, and carrying food capacity were collected with a direct method in the field with vegetation analysis. Carrying capacity estimation is based on data on productivity, land cover area, proper use, and Sumatran elephant food needs in a day. The habitat suitability model used the present coordinate point data from the GPS collar period of January-December 2022 with eight environment variables. The data were then analyzed for the build Sumatera Elephant habitat suitability model using the Maximum Entropy (MaxEnt) algorithm. We recorded 95 species of the potential Sumatran elephant food. The total feed productivity is 1,032,740.722 kg/ha /day and the carrying capacity is 258 elephants. There were three models of habitat suitability categories: high 4,238.66 ha (7%), medium 8,522.34 ha (14%), and low 11,130.36 ha (18%). The studied landscape can adequately accommodate the current population of Sumatran elephants depending on landscape governance (policy and spatial planning) outside conservation areas.
Keyword: conservation, essential ecosystem area, habitat suitability, MaxEnt, Modelling

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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