Judul: Pengendalian gulma pada perkebunan kelapa sawit ( Elaeis guineensis Jacq.) di kebun bangun koling, PT Nabatindo Abadi, Provinsi Kalimantan Tengah
Abstrak: Magang ini dilaksanakan di Bangun Koling Estate (BKLE) PT Windu Nabatindo Abadi (WNA) dari Februari sampai Juni 2015. Tujuan kegiatan ini adalah menambah pemahaman, meningkatkan keterampilan, dan kemampuan bekerja secara langsung mengenai budidaya kelapa sawit khususnya pada pengendalian gulma kelapa sawit. Pengamatan yang dilakukan meliputi gulma dominan di piringan dan pasar pikul dengan parameter pengamatan yang terdiri atas spesies, frekuensi, kerapatan, dan bobot basah. Pengamatan lain adalah teknik pengendalian gulma, efektivitas dan efisiensi, dan alat pelindung diri (APD). Data gulma dominan dianalisis dengan menggunakan analisis nisbah jumlah dominansi (NJD), sedangkan pengamatan lain dianalisis secara deskriptif. Gulma pada piringan dan pasar pikul BKLE didominsi oleh Ageratum conyzoides, Centotheca lappacea Cyrtococcum accrescens, Mikania micrantha, Panicum repens. Pengendalian gulma yang dilakukan secara manual dan kimia, efektivitas dan efisiensi pengendalian kimia lebih baik karena biaya yang di keluarkian lebih sedikit. Persentase penggunaan APD sebesar 84% pada pengendalian manual dan kimia sebesar 91%....
Keyword: Bear market, Effectiveness, Efficiency, Dominant weed, Plate, Agriculture, Oil palm cultivation, Weed control, Ageratum conyzoides, Panicum repens

Judul: :Pengendalian Gulma pada Perkebunan Kelapa Sawit (Elaeis guineensis Jacq.) di Kebun Bangun Koling PT Windu Nabatindo Abadi
Abstrak: This intership was conducted at Bangun Koling Estate (BKLE) of PT Windu Nabatindo Abadi (WNA) from March to June 2014. The aim of this activity were to improve knowledge, skill, and experience about oil palm plantation in general and specifically about weed control of oil palm plantation. Collection of data and information was carried out by direct and indirect methods. The author observed weed domination in harvester path of BKLE with observation parameter consisting of species, frecuency, density, and biomass wet weight. Another observation was the damage symptom of voluntary oil palm seedlings (VOPs) spraying in the circle 4 weeks after application. The output of weed domination observation was analyzed with Summed Dominance Ratio (SDR), while VOPs spraying was analyzed descriptively. The harvester path of BKLE was dominated by Nephrolepis biserrata, Ageratum conyzoides, Cyperus rotundus, and Digitaria adscendens. VOPs spraying caused many VOPs dead but few keep growing.
Keyword: Bogor Agricultural University (IPB), weed domination, VOPs damage, summed dominance ratio, harvester path, circle

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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