Judul: Komunitas Semut Pada Bunga Jantan Kelapa Sawit di Kebun Cimulang PTPN VIII Bogor, Jawa Barat.
Abstrak: Ants are the most successful eusocial insect in the world, since highly adapted to the environment. The objective of this research was to study ants community on male flower of oil palm. Observation of ants were done by using fix sample method during 10 minutes in 3 time periods, which is in the morning (08. 00 - 10.00 am), noon (10. 00 - 12. 00 am), and evening (13. 00 - 15. 00 pm). The observations of ants were conducted during four days in each month, i.e. April, May, June 2012. During observation we collected ant samples to identification process. Weather elements, i.e. air temperature, humidity, and light intensity were measured. Results showed that ant community on male flower of oil palm consist of nine genera belong to four subfamilies, i.e. Leptanilla (subfamily Leptanillinae), Oecophylla, Polyrhachis, Plagiolepis, Camponotus (subfamily Formicinae), Odontoponera, Platyhyrea, Pachycondyla (subfamily Ponerinae), and Myrmica (subfamily Myrmicinae). Leptanilla was a dominant ant species on male flower of oils palm. Diversity of ant community on male flower of oils palm was lower (H ’=0,99) and medium evennes (E=0,45).
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Judul: Keragaman Serangga Pengunjung Bunga Jantan Kelapa Sawit .. (Elaeis guineensis Jacq.)
Abstrak: Oil palm (Elaeis guineensis Jacq.) is one of the plantation crops that became the source of non-oil foreign exchange earner in Indonesia. Oil palm is monoecious plant, in which the same tree bears male and female flowers. Generally a male and female flowers do not bloom simultaneously. Consequently, cross-pollination with weevils help is needed. A weevil species, Elaeidobius kamerunicus is an effective pollinating insect of oil palm because it is specific and well adapted either in wet or dry seasons. The objective of this research was to study the diversity of insects that visit male flowers of oil palm besides E. kamerunicus. The observations were conducted during three days in each month, ie May, June and July 2011 for 10 minutes using fix sample method. During the observation, the name and the number of individual species of insects visiting the male flowers of oil palm were recorded. Performance of weather elements, ie temperature, humidity, and light intensity were measured. Further, insects identification were conducted in the laboratory. Results showed that, besides E. kamerunicus, in PTPN VIII, AFD IV Toge, Garden Cikasungka Bogor were found Rhynchomyia, Scaptodrosophila (Diptera), Diplatys, Forficula (Dermaptera), Camponotus, Dolichoderus, Cerapachys, Crematogaster, and Heteroponera (Hymenoptera). Scaptodrosophila was the dominant visitor insect. Dermaptera and Hymenoptera were predatory insects. The diversity and evennes of insects visiting male flowers of oil palm were low (H’ = 0,59 and E = 0,27).
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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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