Judul: Response of Growth and Production of 4  Varieties of Chili Pepper (Capsicum frutescens L.) to Fertilizer Type
Abstrak: The purpose of this experiment was to study the response of the type of fertilizer on the growth and production of four varieties of chili pepper. The research was carried out at the Tajur 2 Experimental Station, Tropical Horticultural Research Center, Bogor Agricultural University, from January to July 2021. This study used a Split Plot Experimental Design Completely Randomized Group Design (CRBD). The main plot consisted of four varieties of red chili pepper consisting of Bonita IPB (V1), Feira IPB (V2), Taruna (V3), and Cakra Putih (V4). Sub-plots are types of fertilizer consisting of, NPK (16-16-16) + foliar fertilizer (P1), NPK (15-15-15) (P2), and AB mix (P3). The results show the diversity of varieties on several observed characters. Bonita IPB variety was superior to the characters of harvest age and plant height. The characters of flowering age, stem diameter, leaf length and leaf width, fruit length and fruit diameter, fruit weight, number of fruit plant, and productivity of Bonita IPB variety were equivalent to the range of values in the variety description. Taruna variety was superior in terms of harvest age and plant height. Cakra Putih variety had the same harvest age and stem diameter as the variety description. Chili pepper plants treated with NPK fertilizer (16-16-16) + foliar fertilizer showed higher observed character values in stem diameter, number of branches, and leaf length. Other types of fertilizers had no effect on the observed characters. There was no difference in the response of varieties to the type of fertilizer tested.
Keyword: Bonita IPB, capsaicin, NPK, quantitative character, superior varieties

Judul: Pengaruh Jenis Pupuk terhadap Pertumbuhan dan Hasil Empat Varietas Cabai (Capsicum annuum L.)
Abstrak: Cabai (Capsicum annuum L.) merupakan tanaman yang memiliki nilai ekonomi yang tinggi. Tingginya permintaan konsumsi cabai mendorong dilakukannya upaya budidaya untuk meningkatkan kualitas dan produktivitas cabai. Pemberian pupuk yang tepat merupakan salah satu upaya untuk menghasilkan kualitas karakter yang unggul dan produktivitas tinggi. Percobaan dilakukan di Kebun Percobaan PKHT Tajur 2 IPB pada bulan Januari hingga Juli 2021. Percobaan menggunakan rancangan perlakuan petak terbagi dalam rancangan kelompok lengkap teracak. Petak utama yaitu varietas: Harita IPB, Shiara, Genie dan Bara. Anak petak yaitu pemupukan: P1 (NPK 16:16:16 + gandasil B/D), P2 (NPK 15:15:15), P3 (AB mix). Varietas Harita IPB memiliki umur berbunga dan umur panen yang lebih cepat dibandingkan varietas lainnya. Varietas Shiara memiliki ukuran buah dan bobot buah lebih besar dari varietas lainnya. Jenis pupuk tidak berpengaruh nyata terhadap peubah yang diamati kecuali umur panen dan bobot buah. Varietas menunjukkan keragaman dalam umur berbunga, tinggi tanaman, ukuran dan bobot buah. Respon varietas terhadap jenis pupuk menunjukkan perbedaan yang nyata pada umur panen, ukuran daun dan diameter buah. Cabai varietas Bara memberikan produktivitas yang paling tinggi. Kata kunci: pemupukan, produktivitas, varietas, Chilli pepper is a plant that has high economic value. The high demand for consumption of chilli pepper encourages cultivation efforts to improve the quality and productivity of chilli pepper. Appropriate fertilizer application is one of the efforts to produce superior character quality and high productivity. This study was conducted at experimental stasion of PKHT Tajur 2 IPB from January to July 2021. Experiment was arranged in a split plot with randomized complete block design . Main plot factors was on varieties: Harita IPB, Shiara, Genie and Bara. The subfactors was on application of fertilizer: P1 (NPK 16:16:16 + gandasil B/D), P2 (NPK 15:15:15), P3 (AB mix). The Harita IPB variety has a faster flowering and harvesting age than other varieties. The Shiara variety has larger fruit size and fruit weigh than other varieties. Varieties showed diversity in flowering age, plant height, fruit size and weight. The response of varieties to the type of fertilizer showed significant differences in harvest age, leaf size, and fruit diameter. Bara variety gave the highest productivity. Keywords: fertilization, productivity, variety
Keyword: fertilization, productivity, variety

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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