Judul: Keefektifan Kitosan dan Aktinomiset dalam Pencegahan Busuk Antraknosa (Colletotrichum capsici (Syd.) Butler & Bisby) Buah Cabai Merah
Abstrak: Anthracnose due to Colletotrichum capsici is one disease that can decrease the quantity and quality of chillies production in Indonesia. Chitosan and actinomycetes are now widely used in controlling various plant diseases. The objectives of this research have been designed to evaluate the effectiveness of chitosan and two isolates of actinomycetes in preventing anthracnose on red chilli. In vitro test was conducted through baiting poisonous methods, while in vivo test has been done by solution coating of chitosan, isolate actinomycetes of APS5 and APS12, and their combination on the red chilli. The experiment had been done in a completely randomized design with 4 replications. The variables observed were the diameter growth of fungal colonies C. capsici, relative prevention growth, disease severity, and the rigidity of red chilli. The results of in vitro experiment showed that the concentration suspension of APS12, APS5, and APS512 (10%) were effective in suppressing the growth of C. capsici with 57%-72% of relative prevention growth. In vivo experiment showed that the coating of 1% CT, CTAPS5, CTAPS12 could reduce disease severity of C. capsici and lengthen the shelf life of red chilli until 10 days.
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Judul: Keefektifan Agens Antagonis dalam Pengendalian Rebah Kecambah Cabai Merah
Abstrak: One of the major problems during cultivating of chilli is antrachnose disease. The cause of chili anthracnose can various as Colletotrichum acutatum, C. gloeosporoides, and Gloeosporium piperatum. Pathogens can cause seed decay, damping off, and anthracnose fruit rot. The objective of experiment is to evaluate the effectiveness of several antagonist agents in controlling damping off disease. The identification results show that the cause of anthracnose which can be isolated from the seeds and chilies are Gloeosporium piperatum. Antagonist agent Trichoderma harzianum (TH1), Gliocladium fimbriatum (G84), Bacillus subtilis (B12), and Pseudomonas fluorescens (P1) can inhibited the growth of pathogen colonies in vitro as 100%, 100%, 95.43%, and 39.83%. In the in vivo test is known that isolates TH1, G84, B12, and P1 is very effective (100%) in the controlling of chili damping off. Both of single treatment or combination treatment antagonist agents were not different significantly to control the damping off disease. The fourth of antagonist agents are very potential in controlling the damping off disease of red pepper germination
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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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