Judul: Wood Decomposers in Six Community Wood Species at Two Locations
Abstrak: Kayu memiliki hubungan erat dengan rayap dan jamur sebagai dekomposer. Penelitian ini bertujuan menganalisis jumlah kayu terserang rayap dan jamur pada enam jenis kayu rakyat selama enam bulan pengujian pada dua lokasi berbeda, menganalisis tingkat kerusakannya, serta mengidentifikasi spesies rayap dan jamur yang menyerangnya. Penelitian dilakukan pada dua lokasi, yaitu Arboretum Fakultas Kehutanan dan Lingkunan IPB serta permukiman di Bogor Asri, Kecamatan Cibinong, Kabupaten Bogor. Kayu yang diuji adalah Acacia mangium, Falcataria moluccana, Anthocephalus cadamba, Maesopsis eminii, Pinus merkusii, dan Hevea brasiliensis. Pengujian dilakukan berdasarkan ASTM D 1758-06. Jumlah kayu terserang meningkat seiring dengan lama waktu pengujian dan serangannya di arboretum (75%) lebih tinggi dibanding di permukiman (39,4%). Tingkat kerusakan kayu tertinggi di arboretum adalah kayu karet (35,4 g) sedangkan di permukiman adalah kayu pinus (18,9 g). Jenis rayap tanah yang ditemukan adalah Macrotermes sp., Microtermes sp., Schedorhinotermes sp., dan Odontotermes sp. Jenis jamur pelapuk yang ditemukan adalah Aspergillus sp., Mucor sp., Trichoderma sp., Gliocladium sp., Mycelia sterilia, dan cendawan merah., Wood has a close relationship with termites and fungi as decomposers. This study aims to analyze the frequency of termite and fungal attacks on six community wood species during six months testing period at two different locations, to analyze the intensity of wood damage, and to identify the species of termites and fungi that attack them. The research was conducted at two locations, namely the Arboretum of the Faculty of Forestry and Environment of IPB and the settlement area in Bogor Asri, Cibinong District, Bogor Regency. The woods tested were Acacia mangium, Falcataria moluccana, Anthocephalus cadamba, Maesopsis eminii, Pinus merkusii, and Hevea brasiliensis. The tests were carried out according to ASTM D 1758-06. The frequency of attacks increased with the length of time of testing and the attacks were higher in arboretum (75%) than in settlement (39,4%). The highest intensity of wood damage in the arboretum was rubber wood (35,4 g); in settlements, it was pine wood (18,9 g). The subterranean termites found were Macrotermes sp., Microtermes sp., Schedorhinotermes sp., and Odontotermes sp. The rot fungi found were Aspergillus sp., Mucor sp., Trichoderma sp., Gliocladium sp., Mycelia sterilia, and red fungi.
Keyword: arboretum, rot fungus, settlement, subterranean termites

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: 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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