Revista de Ciencia y Tecnología: Envíos recientes
Mostrando ítems 21-40 de 79
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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 ... -
VISCOUS-FLOW MECHANISM OF #6 FUEL OIL – PALM OLEIN MIXTURES
(2012-11-26)The viscosities of mixtures of #6 fuel oil and palm olein at 60 °C do not obey Kendall-‐‐Monroe equation. Molecular considerations predict deviation from ideal-‐‐mixture ... -
SYNTHESIS, CHARACTERIZATION AND REDOX BEHAVIOUR OF MIXED LIGAND COPPER(II) SACCHARINATE COMPLEXES
(2012-11-26)Three mixed-ligand complexes of Cu(II) with saccharin (sac), pyrazole, (Hpz), imidazole, (Himid) were synthesized and characterized on the basis of elemental analysis, FT-IR spectroscopy, magnetic susceptibility, EPR ... -
SOLUCIÓN DE UNA ECUACIÓN DIFERENCIAL PARCIAL DE DIFUSIÓN
(2012-11-26)Utilizing the Laplace transform, an algorithm is shown that solves the partial differential equation, product from the application of the Fick ́s second law of diffusion. ... -
THE LEGACY OF VAN DER WAALS
(2012-11-26)The physical implications of the form and nature of the van der Waals equation of state are explained. The relation of this equation to so-‐‐called van der Waals ... -
Evaluation of three chroroplastic markers for barcoding and for phylogenetic reconstruction purposes in native plants of Costa Rica
(2012-11-26)DNA barcoding has been proposed as a practical and standardized tool for species identification. However, the determination of the appropriate marker DNA regions is still a major ... -
IMPACTO DEL CRECIMIENTO ECONÓMICO INDUSTRIAL SOBRE LOS RECURSOS ENERGÉTICO E HÍDRICO EN COSTA RICA
(2012-11-26)An empirical relationship between water consumption, energy consumption and industrial GDP was established, for the case of Costa Rica. This relationship may be useful in ... -
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 ... -
Graph Theory and simple Hueckel Theory applied to benzene
(2012-11-26)We compare the results of application of graph theory and of simple Hueckel theory in its traditional form to benzene, as an instance of a conjugated molecular system. The ... -
On the classification of constrained extrema
(2011-07-18)Using simple arguments, accessible to students of advanced calculus with an interest in Mathematics, we show the equivalence of several criteria, scattered in the literature, to classify the critical points of functions ... -
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 ... -
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 ... -
Polymers of unidimentional coordination [M(sac)2(H2O)(pyz)]n, (M= Ni2+, Cu2+ and Zn2+, sac =saccharinate, pyz= pyrazine), spectroscopy and magnetic properties
(2011-07-18)Coordination polymers have been prepared by the hydrothermal reaction of M2+saccharinates (M = Ni, Cu and Zn) and pyrazine, pyz, in a ratio 1:1. The complexes of formula [M(sac)2(H2O)2pyz]n, M = Ni2+ and Zn2+ and ... -
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 ... -
Soluciones interiores exactas a las ecuaciones de Einstein para un líquido ideal con simetría axial
(2011-07-18)Exact interior solutions of Einstein equations were obtained, using the ideal fluid model with axial symmetry (Weyl-Lewis-Papapetrou or Weyl-Papapetrou). -
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 ... -
Evaluación de la uniformidad intrínseca en gamma cámaras del servicio de medicina nuclear del Hospital San Juan de Dios
(2009-04-29)The quality assurance program in a Nuclear Medicine Department aims to minimize errors and artifacts that cover all aspects of clinical practice. The quality control can be seen such as one particular procedure used to ... -
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) ... -
Estructura hidrográfica de la Bahía de Bluefields, Nicaragua
(2009-04-29)In March and October of 2000, under the DIPAL II project (Proyecto para el Desarrollo Integral de la Pesca Artesanal en la Región Autónoma del Atlántico Sur), two hydrographic surveys were carried out in the Bay of Bluefields ...