Judul: Performance of Lumbricus rubellus towards Addition of Eggshell Powder as Culture Media with Different Types and Percentages
Abstrak: Lumbricus rubellus adalah salah satu spesies cacing tanah yang sudah banyak dibudidaya karena kegunaannya sebagai bahan pakan ternak dan ikan. Media pemeliharaan cacing tanah yang optimal adalah kotoran ternak dan kompos. Tujuan dari penelitian ini adalah untuk mengamati performa dari Lumbricus rubellus setelah diberi tepung cangkang telur dengan jenis dan persentase yang berbeda. Penelitian ini menggunakan dua jenis tepung cangkang telur yang berbeda yaitu, tepung cangkang telur yang dibuat sendiri dengan kode TTB dan tepung cangkang yang dijual secara komersial di toko pakan hewan dengan kode TTK. Persentase untuk masing-masing tepung cangkang telur yang dicampur dengan kotoran sapi adalah 10%, 20%, dan 30%. Penelitian ini menggunakan Rancangan Acak Lengkap Faktorial dengan dua faktor. Peubah yang diamati terdiri atas pertambahan bobot, jumlah segmen dari klitelum sampai kepala, dan jumlah kokon dari Lumbricus rubellus. Hasil dari penelitian ini diketahui bahwa penambahan tepung cangkang telur sebanyak 10% menunjukkan pertambahan bobot cacing tanah yang lebih tinggi dari perlakuan lainnya tetapi produksi kokon perlakuan tersebut lebih rendah dari kontrol (tepung cangkang telur 0%).
Keyword: eggshell powder, Lumbricus rubellus, performance

Judul: Performa Cacing Tanah (Lumbricus rubellus) pada Media Kotoran Sapi dengan Penambahan Tepung Kulit Kakao
Abstrak: Earthworms are one of the decomposer organisms, decomposition by hworms can be 3-5 times faster than microbes. Earthworm media from cow ng can be added to other wastes that have been fermented or decomposed. Cow ng and cocoa shell waste can be used as a medium for growing earthworms. s study aims to analyze the performance of worms (Lumbricus rubellus) on le manure with the addition of cocoa shell as a living medium with different els. The design used in this study was a completely randomized design (CRD) h 4 (four) treatments and 1 (one) control, each of which was repeated 3 (three) es and analyzed by Tukey's follow-up test. The rearing medium with the ition of cocoa shell flour had an effect (P<0.05) on improving the performance earthworms (Lumbricus rubellus). The addition of cocoa shell powder to cow ng media is up to 15% better than other treatments because it can improve the formance of earthworms (Lumbricus rubellus) including the total worm weight 111.67 grams, cocoon production of 134.00 grains and an average reduced dia of 569.33 grams.
Keyword: cattle manure, cocoa shell, earthworm, performance

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.
Keyword: