Judul: Pengujian repelensi dari empat jenis tanaman terhadap Tikus Rumah (Rattus rattus diardii L.)
Abstrak: Roof rat is one of the pests causing loss to agricultural product and settlements. One of the alternative control to roof rat is using some parts of certain plants as botanical repellent. The objectives of this research is to understand the effectiveness of four various plant as roof rat repellent. Plants that can be used as repellent are noni fruit (Morinda citrifolia L.), soursop (Annona muricata L.), calabash tree (Crescentia cujete L.), and sea mango (Cerbera manghas Gaertn.). The method consist of three trials. Concentrations test (w/v) showed effective concentration are 30% for calabash tree, sea mango, soursop, and 75% for the noni fruit. The average consumption are decreasing with the increasing of concentration. Effectiveness test on four various plant, soursop 30%, sea mango 30%, calabash tree 30%, and noni fruit 75% showed the same effectivity level. The effectiveness of four various plant is lower than zinc phosphide in bait. Repelence level of four various plant is more than 64.23%, field testing needs to be conducted both in settlement and storage
Keyword: Bogor Agricultural University (IPB), roof rat, repellent, plant, concentration, alternative control

Judul: Uji Efektivitas Beberapa Repelen dalam Mengusir Tikus Rumah (Rattus tanezumi Temminck)
Abstrak: Tikus rumah (Rattus tanezumi) banyak ditemukan di sekitar permukiman manusia sehingga kelangsungan hidupnya sangat bergantung pada kehidupan manusia. Salah satu alternatif pengendalian tikus dapat dilakukan dengan menggunakan repelen. Penggunaan repelen diharapkan dapat mengurangi penggunaan rodentisida dalam upaya mengendalikan tikus. Penelitian ini bertujuan mengetahui beberapa jenis repelen yang paling efektif serta perbandingan efektivitas repelen tersebut dalam mengusir tikus rumah. Pengujian repelen dilakukan dengan meletakkan tikus ke dalam kandang non perlakuan dengan repelen dan kontrol diletakkan pada setiap kandang perlakuan berbeda. Repelen diaplikasikan pada potongan kain yang berada pada mangkuk yang terpisah dengan pakan sebanyak 20 semprot (5,5 ml) untuk larutan dan 50 g untuk bubuk siap pakai. Setiap kandang perlakuan diberi pakan gabah dan dibungkus oleh plastik transparan agar kedap udara. Pengamatan dilakukan selama 7 hari dengan memeriksa kandang dan membersihkan sisa pakan. Peubah yang diamati yaitu konsumsi harian dan tingkat repelensi pada setiap perlakuan. Hasil penelitian menunjukkan repelen yang efektif yaitu minyak kayu putih sebagai repelen asal tumbuhan dan karbol sebagai repelen kimia sintetis. Hasil pengujian minyak kayu putih vs karbol menunjukkan bahwa repelen asal tumbuhan yaitu minyak kayu putih lebih efektif dalam mengusir tikus rumah daripada repelen kimia sintetis.
Keyword: consumption, control alternatives, repellency level

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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