Now showing items 1-20 of 71

• 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 ...
• Acerca de si pudo o no ser el universo anisotrótipico ﻿

(2011-02-15)
The theoretical and experimetnal problem concerning the origin and formations of the universe is establish in this paper, specially by developing some theories that try to explain this phenomena, and also to settle the ...
• 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 ...
• 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 ...
• Aplicación de las técnicas de punto fijo ﻿

(2011-02-15)
This article will develop a computacional procedure for approximating a fixed point of continuos functions of the simplex into itself using the Brouwer`theorem. We also shows the different applications of the theory of ...
• Aproximación de sucesiones definidas por recurrencia ﻿

(2011-02-11)
It is established that recurrent sequences, xn+1 = f(xn),which converge to a fixed point L where the derivative α = f '(L) satisfies 0 < |α| < 1 and where the rest r(x) = f(x) - L - α(x-L) satisfies r(x) = O(|x - L|1+ ...
• Álgebras-MV artinianas y noetherianas ﻿

(2011-02-11)
We study MV-algebras that satisfacy tha ascending of descending chain conditions on ideals.  We demostrarted, for example, if an MV-algebra is artianan, then it has a finite number of minimal prime ideals. We also show the ...
• Álgebras-MV artinianas y noetherianas ﻿

(2011-02-14)
Estudiamos álgebras-MV que satisfacen las condiciones de cadena ascendente o de cadena descendente por ideales. Por ejemplo, si un álgebra es artiana, entonces tiene un número finito de ideales primos y minimales. También ...
• 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 ...
• Caracterización del producto del proceso de viscoreducción, para la conversión de aceite vegetal, aceite de alga y búnker ﻿

(2013-06-28)
Through the use of a high pressure and high temperature reactor conditions a visbreaking is simulated, with the purpose of producing green fuels, replacing a fraction fuel oil #6 with vegetable oils. A 25% (m/m) of palm ...
• Caracterización y determinación del potencial Aterogénico de quesos producidos en Costa Rica ﻿

(2009-01-13)
Cardiovascular diseases have been one of the main causes of mortality during the past years in Costa Rica. Many risk factors associated to these disorders include the intake of high-fat diets, being cheese an example of ...
• Cálculo de las integrales radiales en dispersión de electrones ﻿

(2011-02-11)
The radial integrals which arise from the distorted wave treatment of photon emission process in electron and positron scattering, involve products of the electron`s (or positron`s) ingoing and outgoing wave functions and ...
• 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 ...
• COMPARACIÓN DE METODOLOGÍAS DE EXTRACCIÓN PARA LIMONENO Y CARVONA EN Lippia alba USANDO CROMATOGRAFÍA DE GASES. ﻿

(2012-11-26)
Abstract Different plants drying procedures, hydrodistillation and solvent extraction by sonication were evaluated for the essential oil extraction of Lippia alba. Quantitative ...
• Control de calidad en espectrometría gamma de bajo nivel ﻿

(2011-02-07)
Low level gamma spectrometry is a very precise techniqueto measure the concentration of nuclides present in different samples in Bq kg-1. The quality control of the procedure and method used be carried out by intercomparison ...
• Curvatura en teorías generalizadas de Yang-Mills ﻿

(2009-01-13)
The curvature in R1+3 spaces with a generalized Yang-Mills connection is studied and the results are analyzed. Other options borne by modifications of the base space are also studied and commented. The present situation ...
• Desórdenes del sistema musculoesquelético por trauma acumulativo en estudiantes universitarios de computación e informática ﻿

(2011-07-18)
The main objective of this research was to establish the correlation of Musculoskeletal Disorders (MSD ́s) by accumulative damage, among university ́s students from the computer science school (ECCI) at the Universidad de ...
• 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 ...
• Diseño, construcción y puesta en marcha de un fotobiorreactor tubular para producir la microalga Chlorella sp. ﻿

(2015-06-17)
The following is an article about the design and construction of a tubular photobioreactor to produce microalgae Chlorella sp. using combustion gases from a fuel-oil boiler. The reactor was build for the treatment of 50 L ...
• 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 ...