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: Evaluasi Mutu Dedak Padi secara Fisik dan Pendugaan Komposisi Kimia di Kecamatan Pulau Rimau Kabupaten Banyuasin Sumatera Selatan
Abstrak: Dedak padi merupakan produk samping dari proses penggilingan padi yang digunakan sebagai penyusun ransum ternak. Dedak padi termasuk bahan pakan yang melimpah tiap daerah tetapi memiliki kualitas beragam. Penelitian ini bertujuan mengkaji kualitas fisik dedak padi local berdasarkan sifat fisik dan pendugaan komposisi kimia di Kecamatan Pulau Rimau. Penelitian ini menggunakan Rancangan Acak Lengkap (RAL) dengan 10 perlakuan dan 4 ulangan. Data yang diperoleh dianalisis menggunakan Analysis of Variance (ANOVA) dan dilanjutkan uji Duncan. Hasil penelitian menunjukkan bahwa sifat fisik dedak padi berupa kerapatan tumpukan, kerapatan pemadatan tumpukan, dan berat jenis di 10 pabrik (7 desa) di Kecamatan Pulau Rimau nilainya sangat nyata (P<0.01) beragam. Kualitas fisik bervariasi dari yang tertinggi dengan nilai KT dan KPT yaitu 344.44 g L-1 dan 522.49 g L-1 dan yang paling rendah KT dan KPT yaitu 309.26 g L-1 dan 445.51 g L-1. Dedak padi P2 (Desa Sumber Agung) memiliki kualitas fisik dan kimia paling tinggi dan dedak padi P9 (Desa Sumber Mukti) memiliki kualitas paling rendah. Dedak padi yang digunakan dalam penelitian tergolong dalam SNI golongan II., Rice bran is a byproduct of the rice milling process which is used as a compiler for livestock rations. Rice bran is an abundant feed ingredient in each region but has varying qualities. This study aims to assess the quality of local rice bran based on physical properties and chemical composition estimates in Pulau Rimau District. This study used a completely randomized design with 10 treatments and 4 replications. The data obtained were analyzed using Analysis of Variance (ANOVA) and continued with the Duncan test. The results showed that the physical properties of rice bran in term of spesific density, bulk density, and heap compaction density in 10 factories (7 villages) in Pulau Rimau sub-district had highly significant (P<0.01) varied. The physical quality in Pulau Rimau sub-district varies from the highest with the value of spesific density, bulk density, heap compaction density is 344.44 g L- 1, 522.49 g L-1 and 1.44 g L-1 the lowest values are spesific density, bulk density, heap compaction density is 309.26 g L-1, 445.51 g L-1 and 1.28 g L-1. Rice bran P2 (Sumber Agung Village) has the highest physical and chemical qualities and rice bran P9 (Sumber Mukti Village) has the lowest quality. The rice bran used in the study was classified as SNI quality II.
Keyword: Physical quality, pulau rimau sub-district, 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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