Judul: Pengaruh Aplikasi Kalsium dan Biopori terhadap Cemaran Getah Kuning dan Kualitas Buah Manggis (Garcinia mangostana)
Abstrak: Gamboge disorder is the major problem limiting marketable yield of mangosteen fruit. Soil calcium (Ca) application has been known to control the gamboge disorder, but the absorption of calcium occasionally becomes ineffective. The objectives of this research are to find the effect of calcium and biopore application to reduce gamboge disorder and increasing quality of fruit. This research was conducted from November 2010 to April 2011 in mangosteen farm at Karacak, Leuwiliang, Bogor and Postharvest Laboratory, Department of Agronomy and Horticulture IPB. The treatment design is based on Randomized Completely Block Design with two factors. The first factor was concentration of calcium and the second factor was biopore application. There were five concentrations of calcium; 0 kg Ca2+/tree/year; 5.33 kg dolomit/tree/year; 3.55 kg kalsit/tree/year; 10.67 kg dolomit/tree/year; 7.11 kg kalsit/tree/year and there were two treatments of biopore; without biopore application and with biopore application. The result showed that calcium factors were significant to reduce gamboge disorder, but the bi opore factors didn’t give significant effect to reduce gamboge disorder. Interaction between 7.11kg kalsit/tree/year with biopore technology were effectif to reduce gamboge disorder in mangosteen peel. In aril, interaction between 5.33 kg dolomit/tree/year with and without biopore technology, were give significant effect to reduce gamboge disorder in aril.
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Judul: Control of gamboge disorder and improved quality of mangosteen fruit through application of two calcium sources in different dosage
Abstrak: Gamboge disorder is a major problem limiting marketable yield of mangosteen fruit. It is known to be related to low calcium content. Result of previous studies indicate that calcium soil application could increace calcium content in the fruit exocarp and reduce yellow latex in the fruit peel, but ineffective in the flesh. It is known that calcium application could not be sufficient for fruit calcium. Fulfillment of calcium in plants is influenced by the source of calcium and its dosage applied. An experiment was conducted to determine the proper combination of calcium source and its dosage in reducing yellow latex of fruit peel and flesh, also improving fruit quality. Implementations of the experiments conducted in the Kecamatan Kota Agung, Kabupaten Tanggamus, Lampung. Factorial experiment was designed with two factors: Calcium sources (calcitic lime (CaCO3) and dolomitic lime (CaMg(CO3)2) and calcium dosage (0, 2, 4, 6 ton ha-1 Ca). Calcium applied to the soil at blooming period. The experiment was laid out on a randomized complete block design. Leaves and fruits were sampled at harvesting period. Observation of the yellow latex in aryl and fruit peel, fruit physical properties carried out on the variables weight, diameter, fruit hardness, total dissolved solids, total titration acid, and preparation of samples for chemical analysis conducted at PKBT laboratory. Results indicated that application of dolomitic lime with calcium doses of 2 ton Ca ha-1 could increase calcium content of the fruit pericarp (especially exocarp) and reduce yellow latex in the fruit peel and flesh. Calcium application did not affect the physical and chemical properties of the fruit.
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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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