Judul: Pemeriksaan Kebebasan Galat-galat Percobaan engan Metode Tetangga Terdekat
Abstrak: Karya ilmiah ini bertujuan untuk menentukan model yang tepat pada percobaan pemuliaan tanaman jagung, memeriksa kebebasan galat-galat percobaan yang diperoleh dari model dengan metode tetangga terdekat, dan menganalisa ada tidaknya kompetisi antar tanaman pada petak-petak yang berdekatan. Data yang digunakan adalah data pengujian hasil varietas jagung dari Balai Penelitian Tanaman Pangan, Bogor. Peubah ciri yang dipilih adalah berat pipilan kering (dalam kg) dan tinggi tanaman (dalam cm). Galat percobaan diperoleh dengan menganalisa kedua peubah ciri berdasarkan model Rancangan Acak Lengkap dan Rancangan Acak Kelompok. Ternyata penggunaan Rancangan Acak Kelompok tidak terlalu efisien karena kondisi kesuburan tanah dapat dianggap homogen. Pemeriksaan kebebasan antar galat-galat percobaan dapat dilakukan dengan metode tetangga terdekat. Hasil pemeriksaan menunjukkan bahwa asumsi kebebasan antar galat-galat tidak terpenuhi.
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Judul: Penarikan contoh tanaman dari suatu petak percobaan uji beberapa varietas jagung ( Zea mays L. ) genjah
Abstrak: Penelitian ini bertujuan untuk memperoleh ukuran con- toh optimum pada percobaan pengujian beberapa varietas ja- gung. Percobaan dilakukan di Kebun Percobaan Citayam, Kabu- paten Bogor dengan menggunakan rancangan acak kelompok. Perlakuan yang dicobakan berupa tiga varietas jagung gen- jah, yaitu Arjuna, Nakula dan Sadewa yang masing-masing terdiri dari tiga ulangan. Setiap petak percobaan dengan ukuran 3.20 m x 5.04 m diberi 72 lubang yang terdiri dari empat baris dan 18 lajur. Pupuk yang diberikan adalah Urea, TSP dan KCl masing- masing dengan dosis 300 kg/ha, 200 kg/ha dan 100 kg/ha. Peubah-peubah yang diamati adalah panjang daun, lingkar batang, tinggi tanaman dan jumlah barisan tongkol. Penarikan contoh dilakukan dengan rancangan acak se- derhana dalam berbagai ukuran contoh mulai dari 2, 4, 6 sampai dengan 20 tanaman. Untuk ukuran contoh 2, 4, 6, 8, 10 dan 12 dilakukan penarikan contoh sebanyak sepuluh ka- li, sedangkan ukuran contoh 14, 16, 18 dan 20 dilakukan penarikan contoh sebanyak lima kali.
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Judul: Thermal Characteristics and Dynamics of Tropical Cyclone over Western North Pacific Ocean: A Case Study of Typhoon Songda (Chedeng) 2011
Abstrak: The frequent occasion of Tropical Cyclone (TC) over Western North Pacific (WNP) Ocean lies from 10˚N to 26˚N and 121˚E to 170˚E. Sources of TC development come from warm ocean temperature where latent heat is released during condensation processes and subsequently concentrated in the boundary layer. Relative humidity at 850-700 hPa is responsible to produce the most intense storm. Meanwhile, weak vertical wind shear between 850-200 hPa is one of the dynamical factors that lead to the development of TC. Pressure level of 850-200 hPa is chosen to minimize the thermodynamic effect in the lower troposphere. Typhoon Songda (Chedeng in the Philippines) or TSC lasted from May 18th to 30th, 2011 and strengthened into powerful Super Typhoon stage between May 24th and 27th. Long curving track and the exhibition of all sequences of TC life cycle, TSC is then considered as an ideal case of TC. The objective of the study with case of TSC is to investigate the role of thermal characteristics and dynamics on TC intensity. The research is carried out by using Advanced Research of Weather Research and Forecasting model (WRF ARW model) version 3.3. Two domains are employed in the model. The first domain situate from 02˚N to 40˚N and 118˚E to 149˚E and cover spatial resolution () of 33.1 km. The second domain situate from 09˚N to 27˚N and 119˚E to 132˚E with of 11 km. Timestep of the model () is 120 seconds. The model is supported by the following physical parameterization, i.e., Yonsei University Scheme (YSU) in the boundary layer, Kain-Fritsch scheme (KF) in the cumulus, and WRF Single-Moment 3-class scheme in the microphysics. Initial meteorological condition prior to the formation of the cyclone is generated using WRF ARW standard-release model. Sensitivity of the model output is obtained from a selected single-parameter change scenarios, namely, 10 % to 20 % decrease and increase of wind shear initial data at 850-200 hPa, and by 10 % to 20 % decrease of relative humidity initial data at 850-700 hPa. The result showed that the negative correlations between wind shear and intensity are found in wind shear scenarios. Wind shears of 10 ms-1 which lead to strengthening of the wind intensity in the early period of Typhoon development are found in wind shear scenarios. The effect of wind shear changes on wind intensity is statistically significant in the 20 % wind shear scenarios. During mature stage, weak wind intensity occurred when wind shear increase as given in the WRF standard-release and the 20 % decreasing scenario. Different situation is found in the 20 % increasing scenario where wind shear tend to weak and lead to strong wind intensity at this stage. Meanwhile, the reduction of moisture supply at 850-700 hPa resulting from 20 % decreasing relative humidity play a major role in the weakening of wind intensity and reduces mechanical energy of the cycle process as much as 300 J kg-1.
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