Judul: Analisis efektivitas pengendalian gulma secara mekanis, kimia dan kombinasi pada kebun tebu rakyat di Cimahpar, Bogor
Abstrak: This research aims to study any weed control methods on sugarcane plantation, was conducted on sugarcane plantation in Cimahpar, North Bogor – Bogor from May to August 2010. The experimental used ten levels of weed control treatments and two replications. The treatments were Ko = without weed control, M = mechanical, MM = mechanical – mechanical, MMM = mechanical –mechanical - mechanical MK = mechanical – chemical, MMK = mechanical – mechanical – chemical, MKM = mechanical – chemical – mechanical, K = chemical, KM = chemical – mechanical and KMM = chemical – mechanical – mechanical. Controlling method chemically used two varies herbicide, gliphosate and paraquat, while controlling method mechanically was conducted by using walking type cultivator. Glyphosate herbicide has been used on sugarcane area dominated by Imperata cylindrica and paraquat herbicide has been used on sugarcane area dominated by grass or Paspalum conjugatum. The result showed that the treatment of MMK could suppress the growth of weeds, especially Imperata cylindrica is the best in the percentage of weeds by 0.75% and 1.505 cm high weeds on domination Imperata cylindrica areas. MKM treatment showed suppression of growth of weeds, especially Paspalum conjugatum of the best weed in the percentage of weeds 9% and 4.39 cm high weeds on sugarcane Paspalum conjugatum areas. Paraquat herbicide usage caused poisoning symptoms in sugarcane with exist of color change on sugarcane stem, further symptoms was not causing death.
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Judul: Uji Efektifitas herbisida metsulfuron Metil dan Paraquat Serta kombinasinya terhadap Pengendalian Gulma Tanaman Karet Belum Menghasilkan (TBM)
Abstrak: Populasi gulma yang beragam sering menyebabkan herbisida yang diaplikasikan secara menjadi tidak efektif dan ekonomis, karena itu campuran dua atau lebih jenis herbisida yang kompatibel sering digunakan. Dalam percobaan digunakan herbisida metsulfuron metil dan paraquat untuk mengendalikan gulma tanaman karet belum menghasilkan. Percobaan dilakukan di kebun Cikasungka-Cigudeg-Bo- gor dari tanggal 16 Januari sampai dengan 10 April 1991. Rancangan percobaan adalah acak kelompok dengan 2 faktor dan 16 kombinasi perlakuan, serta 3 ulangan. Pengamatan dilakukan pada penutupan gulma, keracunan tanaman karet, dan bobot kering gulma dominan setelah aplikasi herbisida. Gulma dominan di lokasi percobaan terdiri dari golongan daun lebar: Borreria alata, Mikania micrantha dan Nephrolepsis bisserata; dan golongan berdaun pita : chaemum timorense dan Paspalum conjugatum. Perlakuan metsulfuron metil dosis 15 gram b.a./ha dan paraquat dosis 276 gram b.a./ha menghasilkan penutupan gulma, bobot kering gulma total dan I. timorense yang lebih rendah dibandingkan dengan dosis 0 gram b.a./ha...
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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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