Judul: Evaluasi Kualitas Dedak Padi Lokal Berdasarkan Karakter Fisik dan Pendugaan Kimia di Kabupaten Asahan Sumatera Utara
Abstrak: Dedak padi merupakan hasil produk samping dari penggilingan beras menjadi padi yang dimanfaatkan sebagai salah satu bahan pakan ternak. Kualitas nutrien dan produksi dedak padi dari setiap daerah berbeda-beda. Penelitian ini betujuan mengkaji kualitas dedak padi berdasarkan karakter fisik dan pendugaan komposisi kimia berdasarkan model matematika dedak padi di daerah Asahan Sumatera Utara. Penelitian ini menggunakan rancangan acak lengkap (RAL) dengan 8 perlakuan dan 4 ulangan. Data penelitian dianalisis dengan ANOVA, jika terdapat hasil yang signifikan dilanjutkan dengan uji Duncan. Nilai KT dan KPT tertinggi yaitu 348,92 g L-1 dan 510,34 g L-1 , Nilai KT dan KPT paling rendah adalah 296,57 g L-1 dan 392,08 g L-1 . Desa Simpang Jampalan Kecamatan Simpang Empat memiliki kualitas dedak padi tertinggi, sedangkan Desa Pasar VI Kecamatan Rawang memiliki kualitas dedak padi paling rendah. Dedak padi hasil penelitian termasuk dalam mutu II dan III SNI., Rice bran is a by-product of milling rice into rice which is used as an animal feed ingredient. Nutrient quality and rice bran production from each region are different. This study aims to examine the quality of rice bran based on physical characteristics and estimate chemical composition based on the mathematical model of rice bran in the Asahan area of North Sumatra. This study used a completely randomized design (CRD) with 8 treatments and 4 replications. The research data were analyzed by ANOVA, if there were significant results, it was continued with Duncan's test. The highest bulk density and compact bulk density values were 348,92 g L-1 and 510,34 g L-1 , the lowest bulk density and compact bulk density values were 296,57 g L-1 and 392,08 g L-1 . Simpang Jampalan Village, Simpang Empat District had the highest quality of rice bran while Pasar VI Village, Rawang District had the lowest quality of rice bran. Rice bran research results are included in the quality II and III SNI
Keyword: Asahan Districts, physical properties, rice bran

Judul: Evaluation of the Quality of Rice Bran  through Physical Properties and Estimation of Chemical Value in Paseh District,  Bandung Regency, West Java
Abstrak: Dedak padi merupakan hasil samping dari proses penggilingan padi, umumnya digunakan sebagai sumber energi pada pakan ternak. Tujuan penelitian ini adalah mengkaji kualitas fisik serta pendugaan komposisi kimia dedak padi di Kecamatan Paseh, Kabupaten Bandung. Penelitian ini menggunakan rancangan acak lengkap (RAL) dengan 10 perlakuan dan 4 ulangan. Analisis data dilakukan dengan analysis of variance (ANOVA) dan dilanjutkan dengan uji Duncan. Kualitas fisik dedak padi berupa nilai berat jenis (BJ), kerapatan tumpukan (KT), dan kerapatan pemadatan tumpukan (KPT) pada sepuluh pabrik (desa) di Kecamatan Paseh, Kabupaten Bandung ditemukan nyata (P<0,05) beragam hasilnya. Hasil uji lanjut didapatkan kualitas tertinggi (KT 261,46 g L-1 ; KPT 385,66 g L-1) hingga terendah (KT 332,76 g L-1 ; KPT 491,16 g L-1). Kualitas dedak padi tertinggi adalah dedak padi dari pabrik (desa) Sukamanah. Dedak padi di Kecamatan Paseh tergolong ke dalam mutu SNI I, II, dan III., Rice bran is a byproduct of the rice milling process, generally used as an energy source in animal feed. This researchwas to evaluate the physical quality and predictions of chemical composition of rice bran in Paseh district, Bandung regency. This research used a completely randomized design (CRD) with 10 levels of treatments and 4 replications. The data obtained were using analysis of variance (ANOVA) and continued with Duncan's test. The physical quality of rice bran in the form of true density (TD), bulk density (BD), and compact bulk density (CBD) from ten mills in Paseh district, Bandung regency are significantly different (P <0,05) with various results. Based on the result of further test, obtained the highest value (BD 261,46 g L-1 ; CBD 385,66 g L-1) to the lowest (BD 332,76 g L-1 ; CBD 491,16 g L-1). Sukamanah mill has the best quality. Rice bran in Paseh district was classified into I, II, and III grades quality of SNI.
Keyword: Bandung Regency, Paseh District, physical properties, rice bran

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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