Judul: Pengaruh Jumlah Mata Tunas Stek terhadap Pertumbuhan dan Produksi Ubi Kayu
Abstrak: This research was conducted to determine effected the number of nodes and of variety on the growth and production varieties of cassava. The research was carried out on January until July 2011 held at the Garden Experiments Cikabayan, Dramaga, Bogor Agricultural University. This research is a continuation of research that has been carried out in August 2010 to January 2011.This study uses a Split Plot Design. Varieties used were Adira 1 (V1), Adira 4 (V2), UJ 5 (V3), and Malang 4 (V4). In a previous study that used 4 stage nodes, which are: 4 nodes (P1), 6 nodes (P2), 8 nodes (P3), and 10 nodes plant (P4) cassava harvest is done as much as 3 times the current 16WAP, 50 WAP, and 57 WAP. The results showed that the varieties are very real effect on stem height, number of tubers, tuber weight, stem weight, diameter and length tuber crops. The best variety at this research is Malang 4. The number of nodes provide tangible effect on stem height at 26 MST until harvest, stem diameter 18-44 MST, the number of tubers at harvest, wet weight of tubers from the initial planting until harvest, the weight of the leaves and stems, diameter and length of tubers during harvested 16 and 50 WAP.
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Judul: Pertumbuhan Tiga Varietas Lokal Ubi Kayu (Manihot esculenta Crantz) pada Kondisi Bulan Lembab
Abstrak: Ubi kayu merupakan makanan alternatif pengganti sumber karbohidrat. Kemudahan penanaman dan ketahanan terhadap kekeringan, ubi kayu sangat potensial untuk dikembangkan. Penelitian bertujuan mengetahui pengaruh penyiraman setara bulan lembab terhadap pertumbuhan ubi kayu lokal varietas Mangu, Genjah Bayam, dan IR Jonggol. Penelitian dilaksanakan di Rumah kaca Kebun Percobaan Cikabayan IPB Dramaga Bogor pada bulan Oktober 2021 sampai Februari 2022. Penelitian menggunakan Rancangan Acak Kelompok dengan dua faktor dan tiga ulangan. Faktor pertama adalah penyiraman yang terdiri dari 163,5 ml hari-1 polibag-1 (100 mm bulan-1 curah hujan) dan 196,3 ml hari-1 polibag-1 (120 mm bulan-1). Faktor kedua adalah varietas yang terdiri dari Mangu, Genjah Bayam, dan IR Jonggol. Penyiraman tidak berpengaruh nyata terhadap semua variabel pertumbuhan ubi kayu. Hasil penelitian menunjukkan varietas berpengaruh nyata terhadap semua variabel pertumbuhan ubi kayu, kecuali bobot batang, tangkai daun, dan daun. Tidak ada pengaruh interaksi antara penyiraman dan varietas pada semua variabel pertumbuhan. Pertumbuhan varietas IR Jonggol lebih tinggi dibandingkan dengan varietas Mangu dan Genjah Bayam., Cassava is an alternative food as a substitute for rice and corn. With the ease of planting and the resistance to drought, it is the potential to develop. The experiment aimed to identify the effects of watering on the growth of local cassava varieties of Mangu, Genjah Bayam, and IR Jonggol. The experiment was conducted in the Greenhouse at the Cikabayan Experimental station of IPB Dramaga, Bogor, from October 2021 to February 2022. The experiment used a randomized block design with two factors and three replications. The first factor was watering consisting of 163,5 ml day-1 polybag-1 (100 mm month-1 rainfall) and 196,3 ml day- 1 polybag-1 (120 mm month-1). The second factor was varieties consisting of Mangu, Genjah Bayam, and IR Jonggol. The watering had no significant effect on all cassava growth variables. The varieties were significantly effect to all cassava growth variables, except the weight of stem, petiole, and leaves. There was no interaction effect between watering and variety on all growth variables. The growth of varieties of IR Jonggol was higher than that of Mangu and Genjah Bayam.
Keyword: growth, oldeman, varieties, watering

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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