Judul: Evaluasi Talas Kimpul (Xanthosoma sagittifolium) (L.) Schott) pada Kondisi Ternaungi
Abstrak: Evaluation of Cocoyam (Xanthosoma Sagittifolium (L.) Schott) in Shaded Conditions. Supervised by EDI SANTOSA and SUWARTO Planting cocoyam in shaded conditions is an effort to use land in unused areas such as under tree stands in an intercropping or agroforestry. To support this, it is necessary to conduct research related to the selection of accessions and appropriate cultivation methods. This study aimed to (1) characterize morpho physiology and study the morpho-physiology and production of tuber accession of cocoyam in the collection of IPB, (2) determine the effect of planting depth on the growth and cormel formation of cocoyam, and (3) determine the growth and production of cocoyam collect in shaded conditions. The first experiment used seven cocoyam accessions which were BPPT's collection, namely S8, S22, S27, S29, S31, S32, and S37. cocoyam accessions were planted under a 50% shade net with a spacing of 50 cm x 50 cm. All data in the cluster analysis used the UPGMA method while the PCA values were analyzed using multivariate statistics. The results show that there are 31 different character. At the similarity level of 63.8%, cocoyam accessions were divided into two groups. Group A consisted of accessions S29 while Group B consisted of six accessions with 3 sub-groups. The first sub-group consisted of accessions S8 and S32, the second sub-group consisted of accessions S22, S27, and S31, and the third sub group consisted of accessions S37. The most diverse morphological characters were the color of the inner stalk and stomatal density. PCA analysis shows that six components have an eigenvalue of more than one, but none of them has a loading vector value of more than 0.5. This means that no character is more dominant than the others. Accessions S8, S29, and S32 were selected for the second experiment because they had more tubers than the other accessions. The second experiment consisted of two research topics that were planting depth and shade level treatment. This experiment uses accessions S8, S29, S32, and one additional accession from the LIPI evaluation, namely S40. Taro accessions were planted under rubber stands with a planting depth of 20 and 40 cm. The results showed that accessions of cocoyam planted at a depth of 20 cm had a heavier cormus weight than accessions of cocoyam planted at a depth of 40 cm. At a planting depth of 40 cm, cocoyam did not form cormels but had a longer cormus. The level of shade used was treatment without shade, 75% shade net, and under rubber stands. Accessions S8, S29, and S32 planted in a 75% shade net yielded better tubers than rubber stands and without shade. Accession S40 did not form tubers in either the planting depth treatment or the shade level treatment.
Keyword: agroforestry, cluster analysis, planting depth, principal component  analysis, tannia

Judul: Adaptation of taro (Colacasia esculenta (L.) Schoot) at different soil water availability
Abstrak: Indonesia is one of the countries with the greatest diversity of taro variety, while the study of taro's morphology and nutritional characteristics is limited. The aim of this study was to evaluate the anatomical of plant and nutritional value of taro tuber. This research observed fourteen genotypes of Colacasia esculenta (7 Eddoe types, 7 Dasheen types) and 3 Xanthosoma genotypes. In three blocks of replications, the eddoe and Xanthosoma genotypes were cultivated using cormel and the dasheen genotypes with sucker. Plant anatomy (leaf, stem, and root) and tuber nutritional characteristics were analyzed. From this research, explained that stomata and epidermis number, length from stomata and epidermis, number leaf epidermis, length of leaf and stem epidermis, also length of root epidermis, endodermis, cortex, and stele among 17 genotypes of taro were statistically different. The diversity of taro based on the nutrition content of tuber between 17 genotypes of taro was considered high, as represented by water, ash, fat, protein, carbohydrate, energy, and glucomannan, which were statistically different.
Keyword: keragaman, perubahan iklim, TALAS; CEKAMAN. AIR, KEKERINGAN, GENANGAN, TALAS, AIR

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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