Search
Now showing items 1-10 of 93
Punto fijo una teoría interdisciplinaria
Punto fijo una teoría interdisciplinaria
(2011-02-15)
We show a survey of the theory of the fixed point by commenting the most important theorems and their applications in the mathematical fields as well as in other disciplines: economy, theory of games and optimization. We ...
Identificación de modelos de orden reducido a partir de la curvatura de reacción del proceso
(2009-01-13)
A general identification procedure is given, for first and second orders plus time delay models, that uses two or three arbitrary points over the process reaction curve. Two simplified versions of the methods are described: ...
Kinetics of the fischer esterification of palm fatty acids with isopropanol and butyl-cellosolve
(2009-01-13)
Fischer esterification of the mixture of palm fatty acids can be achieved in 80% conversion, under conditions of reactive distillation and methanesulphonic acid as catalyst. The volatility of the H2O/alcohol azeotrope ...
Aplicación de la tomografía axial computarizada para la detección de bolsas de humedad en madera seca de gmelina arborea (roxb.)
(2009-01-13)
Due to its excellent growth rate and productivity, Gmelina arborea (Roxb.) is widely used for commercial reforestation in Costa Rica. However during the lumber drying process, the wooden boards show non-uniform values of ...
EEfecto de contaminantes sobre la transferencia de oxígeno en sistemas de aeración analizado mediante un modelo de dos zonas simplificado
(2009-01-13)
A series of unsteady-state reaeration tests were performed in a 1000 l tank at 1-10-3 normal m3/s diffused-air flow rate and 298,65 K water temperature. Three different types of impurities: soybean oil, surfactant, and ...
A model of chemical association in binary mixtures
(2009-04-29)
A general model of chemical association is presented for the correlation of activities of components of a binary mixture A + B with negative deviation from Raoult's law. The model takes into account the coexistence in ...
Nuevas lactonas sesquiterpénicas de Perymenium grande
(2009-01-13)
Three new sesquiterpenes lactonaes were isolated from the aerial parts of Perymenium grande Hemsl. (Asteraceae), collected around Rincón de la Vieja Volcano, Costa Rica. In addition to the three new lactones 1, 3 and 5; ...
La tierra moler o "diatomita" como sistema de remoción de sustancias químicas en el laboratorio.
(2009-04-29)
Experiments were carried out, to determine the capability of diatomite for the disposal of laboratory residues. Experimentation with different organic solvents (ethyl ether, acetone, ethyl acetate, hexane and ethanol) ...
La cinética de la esterificación de ácidos carboxílocos es de segundo orden con repecto al alcohol
(2009-01-13)
Esterification of carboxylic acids with alcohols is considered as AAC2 type reaction. The specific rate of esterification of acetic acid with methanol, in mixtures of acetonitrile-methanol showed a quadratic dependence on ...
Climatología del viento y oleaje frente a las costas de Costa Rica, parte 1.
(2009-04-29)
The climatologically behavior of the wind and waves is studied around the Costa Rica's coasts using re-analysis data from wave forecasting numeric model. It is found that the wind in the Caribbean coasts of Costa Rica is ...