Judul: Financial Analysis of Kratom (Mitragyna speciosa)
Cultivation as a Prospective New Commodity: A Comparative Study with Rubber
Cultivation
Abstrak: Penurunan harga jual karet akibat fluktuasi pasar global mendorong petani di Desa Saujung Giling Manik, Kecamatan Embaloh Hulu, Kabupaten Kapuas Hulu, Kalimantan Barat untuk beralih dari budidaya karet ke budidaya kratom. Tanaman kratom mulai dilirik sebagai komoditas yang menjanjikan di masyarakat karena memiliki harga yang lebih tinggi dibanding karet. Selain itu permintaan untuk ekspor kratom ke luar negeri terus meningkat dan belum dapat dipenuhi oleh eksportir. Penelitian ini menganalisis usaha budidaya kratom di Desa Saujung Giling Manik dibandingkan dengan budidaya karet dengan mempertimbangkan aspek finansial seperti NPV, IRR, BCR, dan payback period. Hasil perbandingan dari kedua usaha menunjukkan bahwa usaha budidaya kratom memiliki keuntungan yang lebih besar dibandingkan dengan usaha budidaya karet. Usaha budidaya kratom dalam jangka waktu 10 tahun dengan luasan 1 ha menghasilkan keuntungan bersih sebesar Rp 195.746.220,47 dengan tingkat pengembalian sebesar 113%, rasio manfaat biaya sebesar 2,09 serta pengembalian modal usaha 1 tahun., The decline in rubber selling prices due to global market fluctuations has encouraged farmers in Saujung Giling Manik Village, Embaloh Hulu District, Kapuas Hulu Regency, West Kalimantan, to switch from rubber cultivation to kratom cultivation. The kratom plant is starting to be looked at as a promising commodity in the community because it has a higher price than rubber. In addition, the demand for kratom exports abroad continues to increase and cannot be fulfilled by exporters. This study analyzed kratom cultivation in Saujung Giling Manik Village compared to rubber cultivation by considering financial aspects such as NPV, IRR, BCR, and payback period. The results of the comparison of the two businesses show that kratom cultivation has a greater profit than rubber cultivation. The kratom cultivation business in 10 years with an area of 1 ha creates a net benefit of Rp 195.746.220,47 with a rate of return of 113%, a cost-benefit ratio of 2.09, and a 1-year payback period.
Keyword: analisis finansial, budidaya kratom, budidaya karet

Judul: Comparative Feasibility Study of Rubber Agroforestry Business in Pelaihari Unit, Tanah Laut Regency, South Kalimantan
Abstrak: Pembangunan agroforestri sudah cukup lama dilaksanakan di Indonesia. Namun, sampai saat ini masih banyak tantangan pengelolaannya, salah satunya informasi skema agroforestri terbaik pada hutan tanaman industri yang masih terbatas. Pemanfaatan hutan karet di Unit Pelaihari Kabupaten Tanah Laut, Kalimantan Selatan milik PT. Inhutani III dikelola oleh dua perusahaan dengan skema agroforestri. Untuk itu, penelitian ini bertujuan menganalisis kelayakan finansial skema agroforestri yang telah dipraktikkan tersebut. Berdasarkan perhitungan analisis finansial, pengelolaan agroforestri karet, baik dengan tanaman sela singkong ataupun jagung adalah layak diusahakan. Namun, pada perbandingan per hektar usaha agroforestri karet, tanaman singkong memberikan nilai NPV, IRR, dan jangka waktu pengembalian (payback period) yang lebih baik dibanding tanaman jagung. Untuk itu, skema agroforestri karet layak diusahakan untuk pengembangan usaha, terutama dengan tanaman sela singkong. Manfaat yang didapat dari tumpangsari tidak hanya sebagai tanaman menghasilkan disaat tanaman utama belum menghasilkan, tetapi dapat meningkatkan pendapatan maksimum., Agroforestry development has been implemented in Indonesia for quite a long time. However, there are still many management challenges, one is the lack of information on the best agroforestry schemes in industrial plantation forests. PT. Inhutani III, in the Pelaihari Unit of Tanah Laut Regency, South Kalimantan, cooperates with two companies to utilize rubber forests under agroforestry schemes. In response, this study aimed to analyze the financial feasibility of the agroforestry scheme that has been practiced. Based on financial analysis, the management of rubber agroforestry with cassava or corn intercropping was feasible. However, in the ratio per hectare of rubber agroforestry business, cassava crops provided better NPV, IRR, and payback period values than corn crops. For this reason, the rubber agroforestry scheme is worth striving for business development, especially with cassava intercropping. The benefits derived from intercropping are not only as a yielding crop when the main crop is not yet harvested but can increase maximum income.
Keyword: agroforestry, financial analysis, plantation forest

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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