Judul: Evaluasi pertumbuhan Jarak Pagar (Jatropha curcas) setelah satu tahun sambung pucuk di tanah masam
Abstrak: Tanaman jarak pagar (Jatropha curcas) merupakan tanaman yang potensial sebagai penghasil minyak yang dapat dibudidayakan dan digunakan sebagai bahan bakar pengganti minyak bumi. Keberhasilan budidaya jarak pagar ditentukan oleh ketersediaan bibit yang bermutu. Salah satu upaya untuk mendapatkan bibit yang bermutu dapat dilakukan penyambungan antara bibit yang mempunyai perakaran yang baik dengan bibit yang berproduksi tinggi. Tanaman jarak pagar dapat ditanam di lahan kritis seperti pada tanah masam. Dari hasil penelitian sebelumnya telah berhasil dilakukan sambung pucuk tanaman jarak pagar dan diseleksi hasil sambungannya di lahan masam selama 4 bulan. Oleh karena itu perlu dilakukan evaluasi untuk melihat pertumbuhan dan produksi tanaman jarak pagar pada periode lebih lama lagi di tanah masam. Tanaman jarak pagar hasil sambung pucuk selama satu tahun dipindahkan dari polibag ke dalam ember berisi tanah masam, kemudian dua minggu setelah dipindahkan dilakukan proses prunning dan dilakukan penyiraman serta pemupukan dengan pupuk kompos dan NPK. Pengamatan karakter vegetatif meliputi pengamatan diameter batang, tinggi tanaman, panjang tunas, panjang total akar primer, jumlah akar besar, jumlah daun, jumlah daun pada cabang, dan jumlah tunas. Pengamatan karakter reproduktif meliputi, jumlah bunga jantan dan bunga betina, waktu berbunga, jumlah infloresen dan jumlah buah. Berdasarkan seluruh parameter hasil kombinasi sambung pucuk hingga 16 minggu setelah tanam JB/3P dan B3/3A dapat dijadikan kombinasi potensial untuk memacu produksi tanaman jarak pagar pada lahan masam di masa mendatang.
Keyword: Jatropha curcas, Grafting, Acid soil

Judul: Evaluasi Pertumbuhan Jarak Pagar (Jatropha curcas) Setelah Satu Tahun Sambung Pucuk Di Tanah Masam
Abstrak: Jatropha curcas is a potential plant can produce oil that can be used as biodiesel. The successful of J.curcas cultivation was determined by avaibility of the good quality of seedling. One of the efforts to obtain high quality of seedling was through grafting between seedlings that have good rooting system and the ones which have high production. J.curcas can be grown on marginal lands such as in acid soil. From previous studies have been performed successfully grafting of the J.curcas planted in acid soil during 4 months. Therefore, it is necessary to evaluate growth and production of J.curcas grafts on the acid soil for longer periods. The one year old J.curcas grafts were planted in acid soil. Two weeks after planted in the new acid soil media they were prunned and fertilized with compost and NPK fertilizers. Observation of vegetative characters consisted of stem diameter, plant height, shoot length, total length of primary roots, number of large roots, total leaf number, number of leaves on shoots, number of shoots. Observation of reproductive characters, were number of male and female flowers, flowering time, and number of fruit per inflorescense. The result showed that J.curcas grafts JB/3P and B3/3A can be used as potential combinations to stimulate the production of J.curcas in acid soil land in the future
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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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