Judul: Pertumbuhan dan Produksi Daun Torbangun (Plectranthus amboinicus Spreng.) dengan Pemupukan Organik dan Pemangkasan
Abstrak: Torbangun is a nutritious crop that increase breast milk because it contains lactagogen. Most study of torbangun plants focuses on pharmacological characteristics of plant. There is a need for research in cultivation techniques using organic fertilizer and pruning. The purpose of this study was to investigate the effect of organic fertilizer and pruning on the growth and leaf production of torbangun plant. This study used randomized block design (RBD) in the first experiment with fertilizer factor and Split plot design in the second experiment with fertilizer and pruning. Both of the experiment used Tukey‟s (Honestly Significant Difference) test. Organic fertilization is divided into 5 levels: without fertilizer, cow manure+rock phosphate, cow manure+rice-hull ash, rock phosphate+rice-hull ash, and cow manure+rock phosphate+rice-hull ash. Pruning is consisted of 2 levels: without pruning and with pruning. The results showed that fertilization using cow manure + rock phosphate + rice-hull ash increased shoot fresh weight of 125.21% compared to without fertilization. Pruning reduced plant biomass and leaf number. Torbangun growth is slow, so harvesting should have been done in a longer interval.
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Judul: Pertumbuhan dan produksi daun Torbangun (Plectranthus amboinicus Spreng.) dengan pemupukan organik dan pemangkasan
Abstrak: Tanaman torbangun berkhasiat untuk memperlancar air susu ibu (ASI) karena mengandung laktagogen. Penelitian mengenai tanaman torbangun lebih banyak di bidang farmakologinya saja, oleh sebab itu perlu adanya penelitian di bidang teknik budi daya dengan menggunakan pupuk organik dan pemangkasan. Tujuan penelitian ini adalah untuk mendapatkan pengaruh pupuk organik dan pemangkasan terhadap pertumbuhan dan produksi daun torbangun. Rancangan penelitian ini menggunakan rancangan acak kelompok (RAK) pada siklus 1 dengan faktor pemupukan, dan rancangan perlakuan Split plot pada siklus 2 dengan pemupukan sebagai petak utama dan pemangkasan sebagai anak petak. Rataan hasil pada masing-masing siklus diuji lanjut menggunakan uji beda nyata jujur (BNJ). Pemupukan organik terbagi menjadi 5 taraf; tanpa pemupukan, pupuk kandang sapi+fosfat alam, pupuk kandang sapi+abu sekam padi, fosfat alam+abu sekam padi, dan pupuk kandang sapi+fosfat alam+abu sekam padi. Pemangkasan terbagi menjadi 2 taraf; tanpa dipangkas dan dipangkas. Hasil penelitian ini menunjukkan bahwa pemupukan yang menggunakan pupuk kandang sapi+fosfat alam+abu sekam padi dapat meningkatkan bobot basah pucuk 125.21% dibandingkan dengan perlakuan tanpa pemupukan. Pemangkasan menurunkan biomasa tanaman dan jumlah daun. Pertumbuhan tanaman torbangun termasuk lambat, sehingga pemanenan harus dilakukan pada umur tanaman yang lebih lama.
Keyword: Bogor Agricultural University, Institut Pertanian Bogor, IPB

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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