Judul: Pertumbuhan dan Produksi Sambung Nyawa dengan Dosis Pupuk Urea yang Berbeda
Abstrak: Penelitian ini bertujuan mengevaluasi pertumbuhan dan produksi sambung nyawa yang diberi pupuk urea dengan dosis yang berbeda. Penelitian ini menggunakan Rancangan Acak Kelompok (RAK) dengan 4 kelompok kemiringan lahan (7%, 5%, 4%, dan 3%) dengan 4 perlakuan pupuk. P0= Kontrol (pupuk kandang 333,91 g tanaman, This research aimed to evaluate the growth and production of Gynura procumbens given different doses of urea fertilizer. This research used a Randomized Block Design (RBD) with 4 groups based on land slope (7%, 5%, 4%, and 3%) with 4 fertilizer treatments. P0= Control (333.91 g plant?
Keyword: nutrient content, urea, production factors, Growth, Gynura procumbens

Judul: The Effect Of Four Types Of Urea Fertilizer on Biomass and Nitorgen Uptake in Paddy (Oryza sativa L.)
Abstrak: Padi merupakan tanaman yang penting di Indonesia karena padi menjadi bahan makanan pokok bagi sebagian besar masyarakat Indonesia. Peningkatan produksi padi membutuhkan pemupukan yang relatif berkesinambungan sehingga aspek efisiensi menjadi penting. Nitrogen (N) merupakan unsur hara makro yang penting untuk padi. Kehilangan hara terutama hara N, adalah masalah yang sering terjadi dan menyebabkan kesuburan tanah rendah. Studi ini bertujuan mengevaluasi pengaruh jenis pupuk urea pada bobot kering biomasa, serapan N dan efisiensi serapan N pada tanaman padi. Penelitian ini disusun dalam rancangan acak lengkap dengan faktor tunggal yaitu jenis pupuk urea. Perlakuan terdiri dari lima perlakuan yaitu urea konvensional Kujang, urea konvensional Pusri, urea slow release Granul dan urea slow release Prill dan kontrol tanpa aplikasi pupuk. Perlakuan diulang empat kali. Sampel tanaman dikumpulkan setiap minggu dari 1 minggu setelah tanam (MST) sampai 12 MST sehingga total pot percobaan adalah 240 pot percobaan. Sidik ragam dilakukan untuk mengevaluasi efek dari perlakuan. Hasil penelitian menunjukan bahwa jenis pupuk urea tidak berpengaruh secara nyata pada berat biomasa, serapan N dan efisiensi serapan N pada 12 MST sebagai akhir pengamatan. Namun, pupuk urea slow release dalam bentuk butiran dan prill cenderung memiliki biomasa, serapan N, dan efisiensi serapan N yang lebih tinggi dibandingkan dengan urea konvensional Kujang dan Pusri., The Effect Of Four Types Of Urea Fertilizer on Biomass and Nitorgen Uptake in Paddy (Oryza sativa L.). Supervised by ARIEF HARTONO and BUDI NUGROHO. Paddy is an important plant in Indonesia because paddy becomes a staple food for most of the Indonesian people. Increasing paddy production requires relatively continuous fertilization so that the efficiency aspect becomes important. Nitrogen (N) is an important macronutrient for paddy. Nutrient loss, especially N, is a frequent problem and causes low soil fertility. This study aimed to evaluate the effect of urea fertilizer types on the dry weight of biomass, N uptake and N uptake efficiency in paddy. This study was set up in completely randomized design with a single factor, namely the type of urea fertilizer. The treatments consisted of five treatments namely conventional urea Kujang, conventional urea Pusri, slow release urea granule, slow release urea prill and control without fertilizer application. The treatments were repeated three times. Plant samples were collected weekly from 1 week after planting (MST) to 12 MST so the total number of experiment pots were 240 pots. Analyses of variance was conducted to evaluate the effect of the treatments. The results showed that the type of urea fertilizer did not effect significantly on biomass weight, N uptake and N uptake efficiency at 12 MST as the end of observation. However, slow release urea fertilizers in the form of granule and prill tended to have higher biomass, N uptake and N uptake efficiency compared to conventional urea Kujang and Pusri.
Keyword: conventional, efficiensy, granule, prill, slow release

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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