Judul: Keawetan Alami Beberapa Jenis Kayu Indonesia Kurang Dikenal dari Kampus IPB Dramaga terhadap Serangan Rayap
Abstrak: The objective of this research was to evaluate the natural durability of Nine Indonesian lesser known species against subterranean termite (Coptotermes curvignathus Holmgren) and dry wood termite (Cryptotermes cynocephalus Light) attacked grown in Dramaga campus Bogor Agricultural University. Sap and hearth woods from nine wood species namely mangium (Acacia mangium Wild), durian (Durio zibethinus), nangka (Arthocarpus heterophyllus), angsana (Pterocarpus indicus), afrika (Maesopsis eminii Engl), rukam (Flacourtia rukam Zoll), trembesi (Samanea saman (Jacquin) Merrill), bisbul (Diospyros discolor Willd), and ki sampang (Evodia latifolia Dc) were used in this experiment. Evaluation of natural durability of wood against termite attacked referred to SNI 01.7207-2006. The results indicated that the weight loss of wood after baited to C.curvignathus and C.cynocephalus were varied among species and positioning wood (sap and hearth woods). It was observed that hearth wood part of nangka wood was the most durable wood against C.curvignathus attacked and it was classified into 2nd class. bisbul, rukam and trembesi woods both sap and hearth wood part and heart wood of angsana wood were classified into 3rd class. mangium and afrika woods both sap and hearth wood parts were classified into 4th class. Ki sampang and durian woods both sap and hearth wood parts and sap wood part of nangka and angsana woods were classified into 5th class. Sap wood part of rukam wood was the most durable wood against C.cynocephalus attacked and it was classified into 2nd class. Bisbul, mangium, ki sampang, afrika, nangka, durian, angsana and trembesi woods both sap and hearth wood parts and heart wood part of rukam wood were classified into 3rd class.
Keyword: hearth wood, sap woodd, subterranean termite, dry wood termite, natural durability

Judul: Keawetan Alami Dua Belas Jenis Kayu dari Hutan Pendidikan Gunung Walat terhadap Serangan Rayap
Abstrak: The objective of this research was to analyze the natural durability of 12 woods species grown in Mount Walat Forest Education, Bogor Agricultural University against subterranean termite (Coptotermes curvignathus Holmgren) and dry wood termite (Cryptotermes cynocephalus Light). Sapwood and heartwood parts of bungur, jabon, puspa, simpur, tanjung, agathis, mahoni, pasang, sungkai, krey payung, and salam with diameter in the range of 15-35 cm were used in this experiment. Assessment of natural durability of wood against termite attacked referred to SNI 01.7207-2006. The results indicated that the weight losses of woods were varied among species and wood part. Sap and heartwoods of filicium, sapwood of bungur, pasang, and heartwood of simpur, and mahoni had the highest natural durability against C. curvignathus (2nd class). Sap and heartwood of salam, heartwood of bungur, puspa, tanjung were classified to 3rd class. Sap and heartwood of pinus, sungkai, sapwood of simpur, mahoni, puspa, tanjung and heartwood of pasang were classified to 4th class. Sap and heartwood of agathis, jabon, and pinus had the lowest natural durability against C. curvignathus (5th class). Almost all parts of 12 woods species tested belonged to 1st class against C cynocephalus except sapwood of agathis, pinus, and jabon belonged to 2nd class
Keyword: termite, sapwood, natural durability, mount walat education forest, heartwood

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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