Judul: Penilaian Ekonomi Agroforest Tembawang di Kabupaten Sintang dan Sanggau Propinsi  Kalimantan Barat
Abstrak: Degradasi lahan dan hutan menyebabkan berkurangnya fungsi lahan dan hutan. Faktanya, di Kabupaten Sintang telah berkurang sebanyak 4.546,44 ha pertahun atau 0,14% dari total lahan serta 25.697,50 ha per tahun telah berkurang dalam rentang waktu 1999-2004. Agroforest Tembawang sebagai salah satu sarana untuk meningkatkan fungsi dari hutan. Agroforest Tembawang merupakan teknologi tradisional Suku Dayak yang mengkombinasikan tanaman perkebunan dengan tanaman MPTs. Tujuan dari penelitian ini adalah menghubungkan Valuasi Ekonomi Total (TEV) dengan keanekaragaman spesies di Tembawang. TEV dihitung menggunakan pendekatan harga pasar, pasar pengganti, dan contingen valuation method (CVM). Keanekaragaman spesies dihitung dengan INP, Indeks Shannon-Wienner, Indeks Simpson, Indeks Kekayaan, dan Indeks Kemerataan. Hasil penelitian memperlihatkan nilai keanekaragaman yang dekat dengan Taman Nasional Bukit Baka-Bukit Raya (TNBB). Rata-rata indeks Shannon-Wienner yaitu 3,1465 untuk Binjai, 3,0016 untuk Tembawang Sanjan, dan lainnya dibawah nilai tersebut. Nilai TEV dari Tembawang Binjai sebesar Rp.518,95 juta/ha/tahun, Rp.439,10 juta/ha/tahun, Rp.270,21 juta/ha/tahun untuk Telaga Satu, Rp.275,61 juta/ha/tahun untuk Tanjung Ria, Rp.175,38 juta/ha/tahun untuk Jatidamar, dan Rp.247,15 juta/ha/tahun untuk Wonoharjo. Nilai TEV disumbang oleh 35,56% dari NTFP, 24,68% oleh kayu bulat, 30,85 oleh karbon stock, 8,79% oleh kayu bakar, 0,06% oleh nilai erosi, serta 0,03 oleh nilai pilihan dan keberadaan. Kurva hubungan keanekaragaman spesies dan TEV membentuk kurva pangkat empat. Sedangkan kurva hubungan kompatibilitas tembawang dan TEV membentuk kurva pangkat tiga.
Keyword: Agroforest Tembawang, economic valuation, diversity index.

Judul: Penilaian Ekonomi Agroforest Tembawang di Kabupaten Sintang dan Sanggau Propinsi Kalimantan Barat
Abstrak: Forest and land degradation has caused decreasing function of forest and land. Currently, 4.546,44 ha/year or 0.14% by total land of Sintang district and 25.697,50 ha/year or 3.13% by total land of Sanggau district has decreased at 1999-2004 (BPS). Agroforest Tembawang is one of effort to increasing function of forest. Agroforest Tembawang is traditional technology of Dayak to combine plantation vegetation with multipurpose spesices (MPTs). The objectives of the research are to conduct Total Economic Value (TEV) of Tembawang and the diversity species of Tembawang which influence to the TEV results. TEV was calculated by using the market price, substitution price and contingency valuation methods and it was based on estimating direct use, indirect use, option and existence value. The diversity species of Tembawang calculated by using INP method, Shannon-Wienner Index, Simpson Index, Richness Index, and Evenness index. The result was obtained that the diversity species of Tembawang Sanjan and Binjai, two of agroforest complex, close the value of diversity species of Bukit Baka-Bukit Raya National Park (TNBB.) Ratation Index Shannon-wienner of tembawang are 3.1465 by Tembawang Binjai, 3.0016 by Tembawang Sanjan, and under its value by Tembawang Telaga Satu, Tanjung Ria, Wonoharjo, and Jatidamar. Therefore, the result was obtained that the TEV of Tembawang Binjai is Rp 518,95 millions/ha/year, Sanjan Rp.439,10 millions/ha/year, Telaga satu Rp. 270,21 millions/ha/year,Tanjung Ria Rp.275,61 millions/ha/year, Wonoharjo Rp.175,39 millions/ha/year, and Jatidamar Rp. 247,15 millions/ha/year. TEV of Tembawang are share 35.56% by Non Timber Forest Product (NTFP), 24.68% by log value, 30,85% by Carbon Stock Value, 8,79% by firewood, 0.06% by erosion value, 0.03% by option value and existence value. The curve of diversity species and TEV of six Tembawang shown fourth degree regression. While, the curve of Compatibility of Tembawang and TEV of six Tembawang,TNBB and Rubber Plantation shown third degree regression.
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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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