Judul: Serangan Rayap Tanah terhadap Tegakan Pohon di Kebun Raya Bogor
Abstrak: Pelestarian dan perlindungan terhadap pohon-pohon yang tersimpan di Kebun Raya Bogor (KRB) perlu dilakukan untuk menghindari kerusakan oleh berbagai macam penyakit maupun serangga perusak termasuk rayap. Penelitian bertujuan menganalisis frekuensi serangan rayap dan mengidentifikasi jenis rayapnya, menganalisis preferensi rayap terhadap jenis pohon, serta tingkat kerusakan pohon akibat serangan rayap di KRB. Penelitian dilakukan dengan menggunakan metode jalur sampling dengan Intensitas Sampling 20%. Hasil penelitian menunjukkan bahwa sebanyak 213 (100%) pohon contoh di KRB terserang rayap. Spesies rayap tanah yang ditemukan sekurang-kurangnya terdapat empat spesies yaitu Coptotermes curvignathus Holmgren, Macrotermes gilvus Hagen, Odontotermes javanicus Holmgren dan Nasutitermes matangensis Haviland. Rayap M. gilvus banyak ditemukan pada pohon Pterocarpus indicus, Dysoxylum spp., Shorea spp., dan Dimocarpus spp.. Rayap O. javanicus banyak ditemukan pada pohon Vitex cofassus, Dehaasia incrassata, Heritiera spp., dan Cordia spp.. Rayap N. matangensis banyak ditemukan pada pohon Canarium indicum, Dysoyylum spp., dan Sindora spp.. Rayap C. curvignathus banyak ditemukan pada pohon Araucaria columnaris, Agathis sp., dan Pinus spp. Tingkat kerusakan pohon contoh akibat serangan rayap sebesar 10-90%., Preservation and protection of trees stored in the Bogor Botanical Gardens (KRB) need to be done to prevent damage by various kinds of diseases and destructive insects including termites. This study aimed to analyze the frequency of termite attacks and to identify the type of termites, to analyze termite preferences for tree species, as well as the degree of tree damage due to termite attacks in KRB. The research was conducted using the path sampling method with a sampling intensity 20%. The results showed that as many as 213 (100%) sample trees in KRB were attacked by termites. There are at least four subterranean termite species found, namely Coptotermes curvignathus Holmgren, Macrotermes gilvus Hagen, Odontotermes javanicus Holmgren, and Nasutitermes matangensis Haviland. Termites M. gilvus are found in Pterocarpus indicus, Dysoxylum spp., Shorea spp., and Dimocarpus spp. Termites O. javanicus are found in Vitex colossus, Dehaasia incrassata, Heritiera spp., and Cordia spp. Termites N. matangensis is found in Canarium indicum, Dysoxylum spp., and Sindora spp. Termites C. curvignathus can be found in Araucaria columnaris, Agathis sp., and Pinus spp. The level of damage to sample trees due to termite attacks is 10-90%.
Keyword: Attack frequency, subterranean termites, termite preferences, tree health

Judul: Keanekaragaman Spesies Rayap Tanah di Lingkungan Pemukiman Kota Bogor, Jawa Barat
Abstrak: Kebutuhan masyarakat Kota Bogor akan tempat tinggal semakin meningkat, sehingga mengubah kondisi lingkungan yang dapat memengaruhi keberadaan organisme pengganggu, terutama rayap tanah. Penelitian ini bertujuan untuk mengidentifikasi spesies rayap tanah dan keanekaragamannya di Kota Bogor, mengetahui karakteristik tanah dan cuaca, serta mengetahui intensitas kerusakan dan frekuensi serangan rayapnya. Penelitian dilakukan di 12 kelurahan contoh. Disetiap kelurahan contoh, ditanam 25 kayu umpan (2 x 2 x 46 cm) dari kayu pinus yang sebelumya telah diberi perlakuan tekanan uap air (105 ℃, 1 bar, 5 jam). Disetiap kelurahan contoh diambil tanah contoh. Data cuaca diukur di salah satu kelurahan contoh. Hasil penelitian menunjukkan bahwa spesies rayap yang ditemukan ada 3 jenis yaitu Microtermes sp., Macrotermes sp., dan Schedorhinotermes sp. Spesies rayap tanah di lingkungan pemukiman Kota Bogor didominasi oleh Microtermes sp. Karakteristik tanah dan cuaca sangat mendukung kehidupan rayap di Kota Bogor. Nilai frekuensi serangan rayap sebesar 38% (tinggi) dan nilai intensitas kerusakan kayu adalah 6-9.
Keyword: frekuensi serangan, intensitas kerusakan, karakteristik tanah, Pinus merkusii, tekanan uap panas

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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