Judul: Perilaku Cacing Tanah (Perionyx excavatus) pada Media Kotoran Sapi: Langkah Awal Domestikasi
Abstrak: The most common found earth worm in Indonesia is Perionyx excavatus. This worm has weight and body length larger than other types of earthworms. This study aimed to observe the behavior of P. excavatus on cow dung media as a first step to facilitate the process of domestication of cultivation. The experimental design used in this research was Completely Randomized Design. Observations were conducted by observing the daily behavior of P. excavatus for 24 hours, by observing the daily behavior P. excavatus were maintained in four media, 100% cow dung, 50% banana midrib : 50% cow dung, 90% banana midrib : 10% cow dung, and 100% soil. Each media were consisted of 3 replication. Data were analyzed using ANOVA. Based on observations, P. excavatus performed 4 main activities, which were movement, resting, eating and mating. The best media to supports the activities of P.excavatus based on the percentage of movement activity and eating was 50% banana midrib : 50% cow dung. To support the production of cocoon, the best media 90% banana midrib : 10% cow dung, and the best media to support the juvenile production was 100% cow dung based on the value of the coefficient of variance were 71.18%, and 10, 23%.
Keyword: Bogor Agricultural University (IPB), Perionyx excavatus, daily behavior, local earthworms

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.
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