Judul: Pengujian Keawetan Empat Jenis Kayu Tanaman Dengan Standar SNI 01.7207-2006: Tinjauan Terhadap Lama Waktu Pengujian
Abstrak: INTRODUCTION : The use of wood is increasing as human population and technology advancement nowadays. Wood durability is one of wood characteristic. In term of wood durability information, proper wood durabulity testing methode is also important. So a standard of wood durability testing is needed. Wood durability standard available in Indonesia is SNI 01. 7207- 2006. On this standard, the term of testing is tend to be less efficient, which is 6 weeks. So, it is necessary to study furthermore to get more acurate and accountable on testing time. Besides, SNI 01. 7207- 2006 standard does not certainly imlpy the species of wood as a control. This research used four species of wood which are rubber wood, sengon, pine and mangium, and expected to be a species references as a wood control species later. MATERIAL AND METHOD : This reseach used rubber wood (Hevea brasiliensis), pine wood (Pinus merkusii), sengon wood (Paraserianthes falcataria), mangium wood (Acacia mangium) and termites (Coptotermes curvignathus Holmgren). The objective is to evaluate wood durability testing methode of termite attack on SNI 01. 7207- 2006 standard, specific on testing time and the best species of wood as a control. The indicator on this research are weight loss, termites mortality and feeding rate. RESULT AND DISCUSSION : The feeding time was executed by 3 weeks, 4 weeks, 5 weeks and 6 weeks. The result shows that weight loss for 3 and 4 weeks rather similar, and also for 4 and 5 weeks feeding time. Whereas, for 6 weeks feeding time quite different with others. Sengon is the bigest rate of weight loss based on the result, which include in level V of durability. Followed by rubber wood in level IV, mangium in level IV and so with pine wood in level IV. From the results it is known that the feeding time of 4 weeks is the most effective time and the wood that could potentially be used as a control timber is wood sengon. Mortality value for all species is high. This is estimated by environment factor, mostly humidity and temperature. The humidity changes affecting on termites activity. The highest feeding rate on third, fourth, fifth and sixth week found in rubber wood species, the lowest feeding rate found in sengon wood species.
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Judul: Perkembangan Jumlah Rayap, Mortalitas, dan Kemampuan Makan Rayap pada Pengujian Laboratorium
Abstrak: The utilization of wood has been increases in accordance with population growth. One of the imperative properties of wood is durability. It is needed a testing with certain standard beside of SNI 01.7207-2006 so that the result will be accurate. The objectives of this research were to understand the time of durability testing of wood efficiently, and to understand the growth of subterranean termites Coptotermes curvignathus Holmgren, mortality, and feeding rate. There were two methods A method (SNI 01.7207-2006), the samples size was equalized whereas in B method, samples weight equalized. In B method, the rubber wood samples gave stable growth of termites at the estimation 79 termites after 36 days whereas albizia wood, there were no colonies at 78th days. Weight loss which was had by albizia wood was lowest than rubber wood. In a week, A method for albizia and rubber woods, termites were able to feed wood as much as 0.36 g, whereas B method the wood eaten for rubber wood was higher than albizia wood which was 0.16 g. The result of the research revealed that rubber wood was more favorable by subterranead termites.
Keyword: SNI 01. 7207-2006, Hevea brasiliensis, Falcataria moluccana, Coptotermes curvignathus

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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