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La naturaleza del enlace químico 2013 ¡No existe tal cosa llamada orbital!
La naturaleza del enlace químico 2013 ¡No existe tal cosa llamada orbital!
(2013-06-28)
Despite the fact that the chemical bond is a fiction, although convenient and nearly harmless, it plays an enormous role in the thinking, and especially the education, of chemists at all levels. Much further fiction has ...
Tecnología y estudios del futuro: a propósito de un libro de Barker y Erickson
Tecnología y estudios del futuro: a propósito de un libro de Barker y Erickson
(2014-07-07)
Futures Studies are important around the world to predict technological and social changes, as demonstrated with a simple Internet search. Paradoxically, these studies are neither promoted nor relevant in Costa Rica, in ...
Calculations of chemical equilibrium with symbolic computation
Calculations of chemical equilibrium with symbolic computation
(2014-07-07)
We show how a processor for symbolic computation can readily enable extensive calculations to describe the equilibria involving gases, the pH of an aqueous solution in the titration of a polyprotic acid, and complex ions ...
Uso de la resonancia magnética nuclear para la determinación de curcuminoides en cúrcuma y curry producidos y vendidos en Costa Rica
Uso de la resonancia magnética nuclear para la determinación de curcuminoides en cúrcuma y curry producidos y vendidos en Costa Rica
(2014-07-07)
Turmeric (Curcuma longa) rizhome is used as a spice to give colour to food, but its extracts have also shown many interesting biological activities that make C. longa valuable for cultivation and consumption. The active ...
Acumulación de cobre en plantas silvestres de zonas agrícolas contaminadas con el metal
(2013-06-28)
Copper is an essential nutrient that is known to result in toxic damages to organisms. Copper salts have been utilized as fungicide because of its protective effect against several diseases in plants, but the repeated use ...
Producción de jarabe de fructosa con enzimas inmobilizadas en un proceso continuo a partir de tiquisque (<i>Xanthosoma sagittifolium</i>)
Producción de jarabe de fructosa con enzimas inmovilizadas en un proceso continuo a partir de tiquisque (<i>Xanthosoma sagittifolium</i>)
(2013-06-28)
High fructose corn syrups (HFCS) are mainly used by the food industry and are produced by enzymatic hydrolysis from cornstarch. The main objective of this project was to produce fructose syrups using tiquisque starch ...
La lógica difusa en ingeniería: principios, aplicaciones y futuro
(2009-01-13)
Fuzzy logic is a mathematical tool that mimics the way humans manage and process information. It is a method of great simplicity for processing of information, decision making and process control. This article discusses ...
Modelación de la transferencia de oxágeno en sistemas de aereación mediante un modelo de dos zonas simplificado
(2009-01-13)
A new two zone simplified oxygen mass-transfer model with an analytical solution was proposed and used to analyze the unsteady state reaeration data of diffused reaeration systems in order to find the volumetric mass-transfer ...
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: ...
Lignanos de Zanthoxylum acuminatum
(2009-01-13)
From the aerial parts of Zanthoxylum acuminatum (Rutaceae) collected in Upala, Alajuela, Costa Rica were isolated the known lignans hinokinin, (+)-asarinin, (+)- piperitol, (+)-kobusin, and epi-kobusin. In addition to the ...