Judul: Productivity of Earthworms Type Lumbricus rubellus with Mustard Green Waste and Papaya Waste
Abstrak: Budidaya cacing dapat mengatasi masalah pencemaran lingkungan melalui pemanfaatan limbah pasar sebagai pakan cacing tanah. Sampah pasar yang banyak dijumpai adalah sampah sayur dan sampah buah. Pakan dari limbah pasar dapat menekan biaya produksi dalam budidaya cacing tanah. Penelitian ini bertujuan untuk mengkaji pengaruh pemberian pakan dari limbah sayur sawi dan buah pepaya terhadap produktivitas cacing tanah Lumbricus rubellus, produksi vermikompos, serta nilai ekonomi budidaya. Penelitian ini mengunakan eksperimen dengan rancangan acak lengkap, empat perlakuan dan tiga ulangan. Hasil penelitian menunjukkan bahwa perlakuan berpengaruh nyata (P<0,05) terhadap bobot badan cacing, panjang badan cacing, dan produksi vermikompos. Bobot badan cacing tanah tertinggi pada perlakuan pakan dengan limbah pepaya (P400) sebesar 1,108 ± 0,128 g, panjang badan cacing tertinggi pada perlakuan P400 (9,367 ± 0,446 cm), dan produksi vermikompos yang menghasilkan degradasi limbah tertinggi pada perlakuan P400 (45,62%). Pemanfaatan limbah pepaya memberikan hasil yang terbaik terhadap pertambahan bobot badan dan panjang badan L. rubellus. Budidaya cacing tanah dapat memberikan nilai ekonomis dengan menghasilkan cacing tanah dan vermikompos., Worm cultivation can overcome environmental pollution problems through the use of market waste as feed for earthworms. Market waste that is often found is vegetable waste and fruit waste. Feed from market waste can reduce production costs in earthworm cultivation. This research was an experiment with completely randomized design, four treatments and three replications. The research aims to investigative the effect of feed with mustard green waste and papaya waste on the productivity of L. rubellus earthworms, vermicompost production, and economic value of cultivation. The results showed that the treatment had a significant (P<0,05) effect on body weight, body length, and vermicompost production. The highest body weight of the earthworm was in treatment with papaya waste (P400) of 1,108 ± 0,128 g, the highest body length of earthworm was in treatment P400 (9,367 ± 0,446 cm), and vermicompost production which resulted in highest waste degradation in treatment P400 (45,62%). The use of papaya waste gives the best result on body weight gain and body length of L. rubellus. Earthworm cultivation can provide economic value by producing earthworms and vermicompost.
Keyword: cow dung, Lumbricus rubellus, mustard green waste, papaya waste

Judul: Productivity of Earthworms (Pheretima sp.) with the Addition of Green Shell Flour as Maintenance Media
Abstrak: Cacing tanah memiliki banyak kemampuan, antara lain: mendekomposisi material organik, dan mengaduk material organik dan anorganik. Faktor lingkungan yang mempengaruhi kehidupan cacing tanah antara lain suhu, pH, kelembaban, tekstur, dan kandungan nutrien. Peningkatan jumlah timbunan dan masih minimnya pemanfaatan limbah cangkang kerang. Penelitian ini bertujuan untuk menganalisis produktivitas cacing tanah Pheretima sp. dengan memanfaatkan limbah cangkang kerang hijau. Penelitian ini menggunakan metode eksperimen dengan Rancangan Acak Lengkap (RAL) dengan 4 (empat) perlakuan dan 3 (tiga) ulangan dan analisis uji lanjut Tukey. Hasil penelitian menunjukkan adanya pengaruh nyata (P<0,05) pada penggunaan feses sapi sebanyak 90% dengan penambahan tepung cangkang kerang hijau 10% lebih baik dari perlakuan lain karena terbukti dapat meningkatkan bobot cacing tanah (Pheretima sp.) sebanyak 33,3 gram dan meningkatkan jumlah konsumsi media sebanyak 262,67 gram. Penambahan tepung cangkang kerang hijau dapat meningkatkan produktivitas cacing tanah pada taraf penggunaan kurang dari atau sama dengan 10%., Earthworms have many abilities, including: decomposing organic matter, and mixing organic and inorganic materials. Environmental factors that affect the life of earthworms include temperature, pH, humidity, texture, and nutrient content. Increasing the number of piles and still minimal utilization of shell waste. This study aims to analyze the productivity of the earthworm Pheretima sp. by utilizing waste green mussel shells. This study used an experimental method with a completely randomized design (CRD) with 4 (four) treatments and 3 (three) replications and Tukey's follow-up test analysis. The results showed that there was a significant effect (P<0.05) on the use of cow feces as much as 90% with the addition of 10% green mussel shell flour which was better than other treatments because it was proven to increase the weight of earthworms (Pheretima sp.) by 33.3 grams and increased the amount of media consumption by 262.67 grams. The addition of green mussel shell flour can increase the productivity of earthworms at a usage level of less than or equal to 10%.
Keyword: green mussel, Pheretima sp., productivity, shell waste

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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