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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) ...
Evaluación y desarrollo de la metacognición en la enseñanza de la química
(2011-07-18)
Metacognition may be defined as the knowledge and regulation of one’s own cognitive system, the capacity to reflect about one’s actions and thoughts. Current views on metacognition pose it as a fundamental factor in achieving ...
Evaluación de las aguas de drenaje del sector de riego de Tamarindo y su influencia sobre el Parque Nacional Palo Verde
(2011-07-18)
The following physicochemical parameters were measured to determine the quality of the drainage water of Tamarindo Irrigation Sector, at the Arenal-Tempisque Irrigation District: temperature, pH, dissolved oxygen saturation ...
Determinación de un modelo para el consumo de energía con suspensión total de sólidos en fluidos newtonianos
(2011-07-18)
The development of a model for the power consumption in a mixing process for the suspension solids in a Newtonian liquid is proposed in this study. As a first step of this research, the critical variables were determined ...
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 ...
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 ...
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 ...
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 ...
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 ...