Judul: Pengaruh Jarak Tanam Terhadap Produksi Tiga Sayuran Indigenous
Abstrak: The purpose this research was to determine the effect of plant spacing (population) on growth and yield of some indigenous vegetables (kemangi, kenikir, and katuk). The research was conducted at Cikabayan experiment garden in Darmaga, Bogor from April until November 2010. The experiment design was a Randomized Complete Design Group one factor with four treatments plant spacing of population [P1] 25 cm × 13:33 cm (population 300 000 plants/ha), [P2] 25 cm × 16 cm (population 250 000 plants/ha), [P3] 25 cm × 20 cm (population 200 000 plants/ha), and [P4] 25 cm × 26.67 cm (population 150 000 plants/ha), with three replications. Observations included plant height, number of leaves, number of branches, weight yields/plant and weight yield/plot. The result of the experiment showed that plant spacing of kemangi did not influence vegetative growth, weight yields/plant and weight yield/plot. Plant spacing of kenikir influenced number of leaves, number of branches, weigth yields/plant and proned influence weight yield/plot on plan spacing 25 cm × 13:33 cm (population 300 000 plants/ha). Plant spacing of katuk did not influence vegetative growth, weight yields/plant and weight yield/plot.
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Judul: Effect of Variety and Spacing Patterns on Growth and Production of Corn (Zea mays L.)
Abstrak: Jagung merupakan salah satu komoditas yang sangat penting di Indonesia. Produksi jagung di Indonesia belum dapat memenuhi kebutuhan nasional. Peningkatan produktivitas dapat dilakukan salah satunya dengan pengaturan jarak tanam dan pemilihan varietas yang tepat. Penelitian ini bertujuan untuk mengetahui pengaruh varietas dan pola jarak tanam yang berbeda serta interaksinya terhadap pertumbuhan dan produksi jagung. Perlakuan yang digunakan yaitu varietas yang terdiri dari varietas jagung hibrida Poneer 27 dan varietas jagung bersari bebas Bisma, dan jarak tanam yaitu jarak tanam jajar legowo sistem double row dan jarak tanam persegi yang masing-masing terdiri dari 2 taraf. Rancangan percobaan yang digunakan yaitu split-plot dengan rancangan lingkungan RKLT, yang diulang sebanyak 3 kali. Varietas jagung Pioneer 27 menunjukkan nilai rata-rata komponen hasil, hasil biji kering ubinan, dan produktivitas yang lebih tinggi (6,12 ton ha-1) dari Bisma (4,62 ton ha-1). Perlakuan jarak tanam tidak berpengaruh nyata terhadap peubah pertumbuah vegetatif tanaman, namun jarak tanam 80 cm × 25 cm menghasilkan bobot tongkol tanpa klobot dan bobot 1000 butir tertinggi. Rata-rata produktivitas dari semua jarak tanam adalah 5,37 ton ha-1., Corn is one of the most important commodities in Indonesia. Corn production in Indonesia has not been able to meet national needs. One of the ways to increase productivity is by setting the spacing and selecting the right varieties. This study aims to determine the effect of different varieties and spacing patterns and their interactions on maize growth and production. The treatments used were varieties consisting of Poneer 27 hybrid corn varieties and Bisma-free pollinated corn varieties, and the spacings were row spacing with double row system and square spacing, each consisting of 2 levels. The experimental design used was a split-plot with an RKLT environmental design, which was repeated 3 times. The Pioneer 27 maize variety showed a higher average yield component, dry grain yield, and productivity (6,12 ton ha-1) than Bisma (4,62 ton ha-1). Spacing treatment had no significant effect on plant vegetative growth variables, but 80 cm × 25 cm spacing resulted in the highest cob weight without cob and 1000 grain weight. The Pioneer 27 maize variety has a higher dry grain yield per tile and productivity than Bisma. The average productivity of all spacings is 5.37 tons ha-1.
Keyword: plant density, maize varieties, vegetative growth, yield components

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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