Judul: Produktivitas jangkrik kalung (Gryllus bimaculatus) umur 21-51 hari yang diberi pakan tambahan tepung kunyit (Curcuma domestica val.)
Abstrak: The aim of this experiment was to investigate the utilization of the turmeric mean feed additive to improve criket productivity and reduce mortality because tumeric meal contains curcuminoid and other active compounds capable inhibiting the growth of pathogens in the digestive tract. The experimental design used completely randomized design, with four threatments and four treatments consisted of four level tumeric meal addition into the ration i.e., 0%; 0.2%; 0.4%; 0.8%.
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Judul: Produktivitas Jangkrik Kalung (Gryllus bimaculatus) yang diberi Pakan Konsentrat Buatan Hasil Substitusi Tepung Daun Singkong Muda.
Abstrak: Jangkrik sangat berpotensi untuk dibudidayakan sebagai sumber protein hewani alternatif, karena jangkrik memiliki kandungan protein yang tinggi sebesar 61.58%. Jangkrik kalung memiliki keunggulan dalam laju pertumbuhan dan konversi pakan. Tujuan penelitian ini mengevaluasi performa jangkrik kalung (Gryllus bimaculatus) yang diberi pakan konsentrat buatan hasil substitusi tepung daun singkong muda dengan persentase yang berbeda. Peubah yang diamati diantaranya konsumsi pakan, pertambahan bobot badan, produksi telur, konversi pakan, dan mortalitas. Penelitian ini menggunakan metode Rancangan Acak Lengkap (RAL) 6 taraf perlakuan dan 3 ulangan. Jangkrik yang digunakan sebanyak 2 160 ekor dengan perlakuan K (konsentrat komersial : daun singkong muda) menjadi kontrol, P0 (0% tepung daun singkong muda : 100% subtitusi tepung kedelai), P25 (25% tepung daun singkong muda : 75% subtitusi tepung kedelai), P50 (50% tepung daun singkong muda : 50% subtitusi tepung kedelai), P75 (75% tepung daun singkong muda : 25% subtitusi tepung kedelai), dan P100 (100% tepung daun singkong muda : 0% subtitusi tepung kedelai). Perlakuan P25 nyata lebih tinggi untuk produksi telur. Kombinasi pakan konsentrat buatan hasil substitusi tepung daun singkong muda dengan daun singkong muda segar dapat meningkatkan produktivitas jangkrik kalung.
Keyword: Gryllus bimaculatus, jangkrik kalung, tepung daun singkong

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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