Judul: Resistensi Relatif Beras Sosoh Lima Varietas Padi Asal Kabupaten Pati Terhadap Serangan Sitophilus Zeamais
Abstrak: Sithopilus zeamais merupakan hama gudang yang sering menyerang komoditas serealia terutama jagung dan beras di daerah tropis, seperti Indonesia. Tingkat kerusakan dipengaruhi oleh seberapa rentan beras terhadap serangan serangga. Penelitian ini bertujuan untuk mengetahui tingkat ketahanan varietas beras lokal di wilayah Indonesia terhadap serangga Sitophilus zeamais. Penelitian ini menggunakan 5 varietas beras, yaitu C4, IR64, Mentikwangi, Pandanwangi dan Rojolele sebagai varietas lokal yang banyak dibudidayakan di wilayah Pati. Sebanyak 200 gram sampel dari setiap varietas diinfestasi dengan 50 ekor serangga dewasa Sitophilus zeamais kemudian diinkubasi selama 3 bulan pada kondisi ruang. Parameter yang diamati pada akhir penelitian adalah populasi serangga, persen biji berlubang, persen fraksi bubuk (frass), persen kenaikan fraksi air, persen susut bobot kering, dan persen kehilangan bobot. Berdasarkan hasil penelitian varietas beras yang paling resisten terhadap serangan Sitophilus zeamais adalah IR64, sedangkan varietas yang paling rentan adalah Mentikwangi. Hasil uji korelasi menunjukkan adanya hubungan antara populasi serangga dalam beras dengan persen biji berlubang, persen fraksi bubuk (frass), persen kenaikan fraksi air, persen susut bobot kering dan persen kehilangan bobot.
Keyword: beras sosoh, penyimpanan, resistensi relatif, Sitophilus zeamais, varietas padi

Judul: Kajian Resistensi Lima Jenis Beras Varietas Lokal Terhadap Serangan Sitophilus zeamais Motsch.
Abstrak: The present study was conducted to evaluate resistance of local rice varieties i.e. Batutegi, Silugonggo, Ciherang, Mamberamo and Indragiri from the attack of post harvest pest Sitophilus zeamais Motsch. The research was divided into two stages, the preparation and the experiments. In the preparation, S. zeamais culture was cultured to get adult S. zeamais aged 7-14 days. In the first experiment, 10 adult insects aged 7-14 days were infested for 7 days. The adults were then removed and discarded. The infested grains were incubated to allow the emergence of progenies. The emerged progenies were counted daily till there was no emergence for 5 days consecutively. From this experiment, the parameters were number of progenies (Nt), development period (D), development index (ID), intrinsic rate of increase (Rm) and weekly multiplication capacity (λ). In the second experiment, 100 gram of rice was infested with 25 adults of S. zeamais for 5 weeks. From this experiment, the parameters used were percentage of weight loss and percentage of holed grain. Based on number of progenies (Nt), development index (ID), intrinsic rate of increase (Rm), weekly multiplication capacity (λ), percentage of weight loss and percentage of holed grain, showed that Silugonggo variety was the most resistance among other tested rice varieties. The values are 57, 12.5239, 0.3781, 1.4596, 10.94%, and 12.45% respectively.
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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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