Judul: Respon Produksi Tanaman Tomat Varietas Tora terhadap Perbedaan Kondisi Iklim Mikro Akibat Pemakaian Mulsa Perak dan Hitam
Abstrak: Tora is non-hybrid tomatoes that cultivated and developed by IPB. This tomato has a high potential production and suitable to be planted in the low land. This research aims to analyze the condition of the microclimate around the tomato plants and determine the treatment effect of mulch types that different in productivity. Location of the research at BMKG precisely in Situgede, Dramaga Bogor. Treatment is done is by providing silver and black mulch on tomato plants, the research was done from February to June 2014 . Result shows that tomato plants are growing more optimal in silver mulch than the black mulch treatment. Agronomic components such as plant height, leaf number, and total dry weight obtained that silver mulch treatment is optimal, but by the statistical treatment the significantly affect only in plant height and number of leaves. Interception of radiation in silver and black mulch treatment respectively amounted to 171.4 MJ m-2 and 208.6 MJ m-2 in planting season. Total of radiation use efficiency in a season was 1.7 g/MJ on silver mulch and 1.8 g/MJ on black mulch. The Comparison of the reflected radiation and the radiation that comes in silver mulch is 0.53, while the black mulch is 0.32. Total fruit weight of each plant in silver mulch is 1370 g and the black mulch is 914 g.
Keyword: Bogor Agricultural University (IPB), specific leaf area, global radiation, heat unit, leaf area index

Judul: Efisiensi pemanfaatan radiasi surya tanaman tomat varietas tora IPB pada sistem budidaya hidroponik bertingkat
Abstrak: Tomat varietas Tora IPB merupakan tomat non hibrida yang dikembangkan oleh IPB. Tora IPB memiliki umur panen 46-61 hari setelah tanam dengan potensi produksi yang tinggi dan cocok ditanam didataran rendah. Penelitian ini bertujuan untuk menganalisis pengaruh kerapatan tiang penyangga bedeng terhadap total biomassa tanaman tomat pada sistem hidroponik DFT (Deep Flow Technique) bertingkat. Penelitian kerapatan penyangga bedeng perlu dilakukan untuk mendapatkan efisien pemanfaatan lahan dengan tetap mempertahankan hasil produksi yang tinggi. Tanaman tomat ditanam menggunakan sistem budidaya hidroponik bertingkat dan datar dengan tiga kerapatan penyangga bedeng dengan sudut 30˚, 60˚, dan 180˚. Semakin kecil sudut, semakin besar kerapatan tanaman. Hasil penelitian menunjukkan tanaman yang ditanam pada sudut 30˚ memiliki tinggi tanaman yang lebih tinggi dengan jumlah daun yang lebih sedikit dan sudut 180˚ memiliki tinggi tanaman yang lebih rendah dengan jumlah daun yang lebih banyak, sedangkan sudut 60˚ berada diantara kedua perlakuan tersebut. Total radiasi di atas permukaan tajuk tanaman selama penelitian sebesar 1942 MJ/m2 dengan suhu rata-rata harian 25.1 ˚C dan kelembaban 62% serta curah hujan total 502 mm. Radiasi intersepsi pada tanaman perlakuan 30˚ sebesar 14 MJ/m2 per hari dan 60˚ sebesar 13 MJ/m2 per hari serta 180˚ sebesar 11 MJ/m2 per hari. Efisiensi pemanfaatan radiasi yang diperoleh selama penelitian adalah perlakuan 30˚ sebesar 1.7 g/MJ, 60˚ sebesar 1.8 g/MJ dan 180˚ sebesar 1.9 g/MJ. Total hasil panen setiap perlakuan yaitu sudut 30˚ sebesar 12 kg/m2 lahan, 60˚ sebesar 9 kg/m2 lahan, dan 180˚ sebesar 5.4 kg/m2 lahan. Penanaman dengan sistem budidaya hidroponik bertingkat dengan sudut 30˚ lebih cocok untuk meningkatkan biomassa tanaman tomat dengan tetap mempertahankan tingginya hasil produksi.
Keyword: Deep flow technique, eficiency use radiation, multilevel hydroponic, radiation interception, tora 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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