Judul: Pests and Diseases of Glutinous Rice Cv. of  Grendel at Various Plant Spacing, Nitrogen and Potassium Fertilizing Doses.
Abstrak: Pemupukan dan pengaturan jarak tanam merupakan aspek penting untuk produksi padi. Penelitian bertujuan mengkaji pengaruh jarak tanam, pemupukan Nitrogen dan Kalium terhadap populasi atau tingkat serangan hama dan penyakit padi. Penelitian dilakukan di Desa Kiarasari, Kecamatan Compreng, Kabupaten Subang pada bulan November 2022 sampai dengan Januari 2023 menggunakan rancangan acak kelompok dengan empat taraf pemupukan dan dua taraf jarak tanam. Hasil penelitian menunjukkan ada pengaruh nyata pemupukan dan jarak tanam terhadap tingkat serangan penggerek batang padi kuning, blas daun, dan hawar daun bakteri, tidak berpengaruh nyata terhadap populasi wereng batang cokelat dan jumlah kelompok telur penggerek batang. Perlakuan yang berpengaruh nyata menurunkan serangan penggerek batang padi kuning adalah F3T2 (90 kg/ha N + 35 kg/ha K dan 50 cm x 25 cm). Perlakuan yang berpengaruh nyata menurunkan keparahan penyakit blas daun adalah F4T2 (135 kg/ha N + 52,5 kg/ha K dan 50 cm x 25 cm). Perlakuan yang berpengaruh nyata menurunkan keparahan keparahan penyakit hawar daun bakteri adalah F2T1 (45 kg/ha N + 17,5 kg/ha K dan 40 cm x 40 cm) dan F3T1 (90 kg/ha N + 35 kg/ha K dan 40 cm x 40 cm)., Fertilizing and plant spacing are important aspects for rice production. The research aims to examine effect of plant spacing, Nitrogen and Potassium fertilizing on the population or damage level by rice pests and diseases. The research was conducted in Kiarasari Village, Compreng District, Subang Regency from November 2022 to January 2023 using a randomized block design with four levels of fertilizing and two levels of plant spacing. The results showed that there was a significant effect of fertilization and plant spacing on the level of damage by stem borers, leaf blast, and bacterial leaf blight, but had no significant effect on the population of brown planthoppers and the number of stem borer egg clusters. The treatment that has a significant effect on reducing yellow rice stem borer attacks was F3T2 (90 kg/ha N + 35 kg/ha K and 50 cm x 25 cm), on reducing leaf blast severity was F4T2 (135 kg/ha N + 52.5 kg/ha K and 50 cm x 25 cm), and on reducing bacterial leaf blight severity were F2T1 (45 kg/ha N + 17.5 kg/ha K and 40 cm x 40 cm) and F3T1 (90 kg/ha N + 35 kg/ha K and 40 cm x 40 cm).
Keyword: blas daun, hawar daun bakteri, penggerek batang padi, bacterial leaf blight, leaf blast, rice stem borer

Judul: Response of Glutinous Rice Varieties (Oryza sativa L.  glutinosa) of N Fertilizer and Plant Spacing Treatments
Abstrak: Penelitian ini dilakukan untuk mempelajari pengaruh jarak tanam dan dosis nitrogen (N) terhadap pertumbuhan dan hasil padi ketan Grendel (Oryza sativa L. glutinosa). Penelitian dilaksanakan di Desa Jatisari, Karawang, Jawa Barat yang berada pada ketinggian 25,6 m dpl pada Januari – Juni 2022. Penelitian menggunakan Rancangan Split Plot dengan dua iiaying perlakuan yaitu jarak tanam sebagai petak utama dan dosis N sebagai anak petak. Faktor perlakuan jarak tanam menggunakan 4 taraf, yaitu jarak tanam 20 cm x 20 cm, 25 cm x 25cm, 30 cm x 30 cm, dan 40 cm x 40 cm. Faktor dosis pupuk 45 kg, 90 kg, 135 kg, 180 kg N ha-1 . Kombinasi perlakuan diulang sebanyak 3 kali. Hasil penelitian menunjukan bahwa jarak tanam 40 cm x 40 cm dan dosis N 180 kg N ha-1 meningkatkan tinggi tanaman, jumlah anakan, warna daun, jumlah anakan produktif, bobot kering sampel, bobot gabah hampa, jumlah bulir per malai, dan hasil ubinan (GKG), This research was conducted to study the effect of plant spacing and nitrogen (N) dose on the growth and yield of Grendel glutinous rice (Oryza sativa L. glutinosa) which was carried out in Jatisari Village, Karawang, West Java (5 – 25.6 m asl). The research was conducted in Januari-Juni 2022. The study used a split plot design with two factors, namely the spacing of the plots as the main plot and the dose of N as the sub-plots. The plant spacing factor used 4 levels, namely the spacing of 20 cm x 20 cm, 25 cm x 25 cm, 30 cm x 30 cm, and 40 cm x 40 cm. The fertilizer dose factor was 45 kg, 90 kg, 135 kg, 180 kg ha-1 . All treatment factors were repeated 3 times. The results showed that a spacing of 40 cm x 40 cm and a dose of N 180 kg ha-1 resulted in higher plant height, number of tillers, darker leaf color, number of productive tillers, dry weight, weight of sterile grain, number of grains per panicle, and yield.
Keyword: Fertilizer dose, glutinous rice, fertilizer application

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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