Judul: Karakterisasi Morfologi Beberapa Genotipe Kentang (Solanum tuberosum) yang Dibudidayakan di Indonesia
Abstrak: The research was conducted at Cikajang Garut West Java from March 2013 until July 2013. The purpose of this research is characterize of vegetative and generative character some genotypes of potato cultivated in Indonesia qualitatively and quantitatively. The genotypes of Potato used consisted of three comparator (Granola, Atlantic, South Sulawesi) and seven tested genotypes (Intan, Bengkulu, Jambi, Bukit Tinggi, Wonosobo, Blis, and Mikraset). Observations consist of a plant height, stem (diameter and color), leaves (number of leaves, color, shape, and size), flowers (flowering time, shape, and color), time of harvest, tubers (the number of tuber, weight, shape, size, color, and moisture content). The research result showed genotype Jambi and Intan has a higher yield than the comparison. Ten genotypes of potato that is used is divided into 3 groups. The first group consists of Jambi, Atlantic, Bukit Tinggi, and Mikraset. The second group consists of Granola, Intan, South Sulawesi, Blis and Wonosobo. The third group is a group that does not have in common with the three comparator namely Bengkulu. Genotypes Bengkulu have the purple stem and red skin of tuber, so it can potentially to do registration of varieties.
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Judul: Preliminary Result Test of Potato Genotype (Solanum tuberosum L.) in Garut District, West Java
Abstrak: Kentang (Solanum tuberosum L.) merupakan salah satu bahan pangan utama setelah padi, gandum, dan jagung di dunia. Konsumsi kentang di Indonesia terus meningkat namun penyediaan kentang belum dapat seluruhnya dipenuhi oleh produksi dalamnegeri. Upaya untuk meningkatkan produksi kentang adalah dengan mengembangkan varietas baru berdaya hasil tinggi. Tujuan penelitian ini adalah untuk mengetahui karakterisasi morfologi dan produktivitas beberapa genotipe kentang IPB di Kabupaten Garut, Jawa Barat dengan varietas pembanding. Penelitian dilaksanakan di Desa Margamulya, Kecamatan Cikajang, Kabupaten Garut, Jawa Barat pada bulan Januari sampai April 2020. Lahan penelitian berada pada ketinggian tempat ± 1,560 m dpl. Penelitian ini menggunakan Rancangan Kelompok Lengkap Teracak (RKLT) faktor tunggal yaitu genotipe dan empat ulangan sebagai kelompok. Faktor yang diamati berupa genotipe, yaitu 8 genotipe kentang IPB dan 2 varietas pembanding yang diulang sebanyak empat kali. Bahan tanam yang digunakan yaitu genotipe kentang PKHT-2019-010, PKHT-2019-011, PKHT-2019-012, PKHT-2019-013, PKHT-2019-014, PKHT-2019-015, PKHT- 2019-016, PKHT-2019-017, serta kentang varietas Intan dan Medians sebagai pembanding. Hasil penelitian menunjukkan genotipe kentang yang diujikan memiliki keragaman daun, batang, bunga, dan umbinya. Hasil penelitian menunjukkan bahwa genotipe PKHT-2019-015, PKHT-2019-010, dan PKHT- 2019-017 memiliki produktivitas paling tinggi, sedangkan PKHT-2019-012 setara dengan varietas pembanding Intan. Genotipe yang memiliki produktivitas lebih tinggi atau sama dengan varietas pembanding diharapkan menjadi genotipe harapan yang dapat dikembangkan sebagai varietas baru.
Keyword: genotipe, keragaan, produktivitas, uji daya hasil

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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