Now showing items 769-788 of 1620

    • Fabricación de tubos de carburo de silicio para uso como cuerpo radiante en hornos y sistemas de calentamiento 

      Vargas, Fabio; López, Esperanza; López, Daniel; Areiza, Jaime; Monsalve, Mónica
      El carburo de silicio (SiC) es un material con alta potencialidad de uso en hornos y sistemas de calentamiento dada su alta conductividad termica, refractariedad, baja expansion termica y estabilidad mecanica a temperaturas ...
      Universidad Nacional de Colombia Revistas electrónicas UN Dyna. 
    • Factores de innovación en marketing estratégico – un caso aplicado al sector delmueble hogar en itagãœi (antioquia) 

      Arango Serna, Martín Darío; Branch Bedoya, Jhon Willian; Pérez-Ortega, Giovanni
      El presente artículo se enmarca dentro de un proyecto que tiene como objetivo analizar el sector del mueble en el municipio de Itagüi (Antioquia). El análisis está dirigido al estudio de los factores principales de innovación ...
      Universidad Nacional de Colombia Revistas electrónicas UN Dyna. 
    • Factors influencing the occurrence of traffic accidents in urban roads: A combined GIS-Empirical Bayesian approach 

      Cantillo, Víctor; Garcés, Patricia; Márquez, Luis
      The problem of urban road accidents in Colombia is remarkable and has a significant magnitude. For this reason, a technical study of this important public health scourge is important. The quantitative techniques employed ...
      Universidad Nacional de Colombia Revistas electrónicas UN Dyna. 
    • Factors involved in the perceived risk of construction workers 

      Rodríguez-Garzón, Ignacio; Martínez-Fiestas, Myriam; Delgado-Padial, Antonio; Lucas-Ruiz, Valeriano
      This article is an exploratory study of perceived risk in the construction sector. We used a sample of 514 workers in Spain, Peru and Nicaragua. The method used was the psychometric paradigm and, under its assumptions we ...
      Universidad Nacional de Colombia Revistas electrónicas UN Dyna. 
    • Facultad de minas 120 años de trabajo y rectitud 

      Vélez Restrepo, Juan Manuel
      Universidad Nacional de Colombia Revistas electrónicas UN Dyna. 
    • Failure analysis and redesign of a wagon wheel shaft for sugar cane transport 

      Casanova García, Gonzalo Fernando
      In this study, a failure analysis of the wheel shafts of wagons for transporting sugar cane is carried out. Several shafts have broken with a small fatigue propagation zone and a large sudden-fracture zone. The material ...
      Universidad Nacional de Colombia Revistas electrónicas UN Dyna. 
    • Fast estimation of earthquake epicenter distance using a single seismological station with machine learning techniques 

      Ochoa Gutierrez, Luis Hernán; Vargas Jimenez, Carlos Alberto; Niño Vasquez, Luis Fernando
      A Support Vector Machine Regression (SVMR) algorithm was applied to calculate the epicenter distance using a ten seconds signal, after primary waves arrive at a seismological station near to Bogota - Colombia. This algorithm ...
      Universidad Nacional de Colombia Revistas electrónicas UN Dyna. 
    • Fast pyrolysis of biomass: A review of relevant aspects. Part I: Parametric study 

      Montoya Arbeláez, Jorge Ivan; Chejne Janna, Farid; Garcia-Pérez, Manuel
      Recent years have witnessed a growing interest in developing biofuels from biomass by thermochemical processes like fast pyrolysis as a promising alternative to supply ever-growing energy consumption. However, the fast ...
      Universidad Nacional de Colombia Revistas electrónicas UN Dyna. 
    • Fault resistance and soil resistivity influence on the impedance based methods for locating faults. a comparative analysis 

      Mora Flórez, Juan José; García Osorio, Germán; Pérez-Londoño, Sandra Milena
      The influence of the soil resistivity and the fault resistance is considered in this paper where a comparison of a well defined impedance based method for locating faults is presented. Tests were performed in a real power ...
      Universidad Nacional de Colombia Revistas electrónicas UN Dyna. 
    • Fácil síntesis en un paso y mecanismo de formación de nanopartículas de plata 

      Ramirez, Daniel Estiben; Jaramillo, Franklin
      En este trabajo se obtuvieron nanoparticulas de plata por la ruta de reducción química usando síntesis en un paso. Diferente a otros métodos reportados para nanoparticulas de plata, se usó 1-octanol como solvente y agente ...
      Universidad Nacional de Colombia Revistas electrónicas UN Dyna. 
    • Fibra de guadua como refuerzo de matrices poliméricas 

      Cuéllar Burgos, Alneira; Muñoz Cuervo, Ismael
      En el presente trabajo se estudió el efecto que tiene la fibra de Guadua angustifolia Kunth con y sin tratamiento químico, empleando hidróxido de sodio al 5 y 10%, sobre las propiedades mecánicas de una matriz polimérica ...
      Universidad Nacional de Colombia Revistas electrónicas UN Dyna. 
    • Fibra micro-estructurada para la compensación de la dispersión cromática en sistemas de comunicaciones ópticas 

      Aristizábal, Victor H.
      En este trabajo se analiza una fibra óptica micro-estructurada que presenta un pico de dispersión anómala aproximadamente de -5800 ps/(nm-km) alrededor 1.547 μm, haciéndola ideal para propósitos de compensación en la tercera ...
      Universidad Nacional de Colombia Revistas electrónicas UN Dyna. 
    • Field study of experimental antifouling paint formulations 

      Jaramillo Isaza, Franklin; Castaño González, Juan Guillermo; Echeverría Echeverría, Félix
      This work presents the results of field testing of several experimental antifouling paints, which were exposed for up to 471 days to natural sea water in the Caribbean. The testing site was selected in order to obtain very ...
      Universidad Nacional de Colombia Revistas electrónicas UN Dyna. 
    • Finding fuzzy identification system parameters using a new dynamic migration period-based distributed genetic algorithm 

      Castro, Marco Antonio; Herrera Fernández, Francisco
      This paper presents a distributed genetic algorithm with dynamic determination of the migration period. The algorithm is especially well suited for the on line estimation of a fuzzy identification system parameters, using ...
      Universidad Nacional de Colombia Revistas electrónicas UN Dyna. 
    • Fine material effect on kaolin suspensions rheology 

      Bustamante Rúa, Moisés Oswaldo; Rojas Reyes, Nestor Ricardo; Quitian Chila, Gali Ronel
      A good rheological characterization can be used as a control parameter within the industrial processing of kaolin. The kaolin used was characterized by SEM, XRD, XRF and particle size. Also it was classified and separated ...
      Universidad Nacional de Colombia Revistas electrónicas UN Dyna. 
    • Fingerprint verification using computational geometry 

      Ramírez Flores, Manuel; Aguilar Torres, Gualberto; Gallegos García, Gina; García Licona, Miguel Ángel
      This paper presents a robust minutiae based method for fingerprint verification. The proposed method uses Delaunay Triangulation to represent minutiae as nodes of a connected graph composed of triangles. The minimum angle ...
      Universidad Nacional de Colombia Revistas electrónicas UN Dyna. 
    • First approach to unilateral transfemoral amputees' contact mechanics 

      Mariaka Flórez, Isabela; Ramírez Patiño, Juan Fernando
      The stresses in the hip area have great importance because of their relationship to the health of the joint. Finite element models can predict contact between cartilages, however, contact patterns in unilateral transfemoral ...
      Universidad Nacional de Colombia Revistas electrónicas UN Dyna. 
    • Flash flotation of free coarse gold using dithiophosphate and dithiocarbamate as a replacement for traditional amalgamation 

      Bustamante Rúa, Moises Oswaldo; Naranjo Gomez, Doria Maria; Daza Aragón, Alan José; Bustamante Baena, Pablo; Osorio Botero, Julian David
      This article develops the flash flotation as an alternative method to gravitational separation and amalgamation in order to achieve a greater recovery of coarse native gold through selective hydrophobicity. This method is ...
      Universidad Nacional de Colombia Revistas electrónicas UN Dyna. 
    • Flatness-based fault tolerant control 

      Martínez-Torres, César; Lavigne, Loic; Cazaurang, Franck; Alcorta-Garcia, Efrain; Diaz-Romero, David A.
      This paper presents a Fault Tolerant control approach for nonlinear flat systems. Flatness property affords analytical redundancy and permit to compute the states and control inputs of the system. Residual signals are ...
      Universidad Nacional de Colombia Revistas electrónicas UN Dyna. 
    • Flower wastes as a low-cost adsorbent for the removal of acid blue 9 

      Echavarria-Alvarez, Ana María; Hormaza-Anaguano, Angelina
      This paper describes the use of flower wastes (carnation, rose and daisy) as a potential, alternative and low-cost adsorbent for the removal of Acid Blue 9 (AB9). The best conditions to achieve an efficient adsorption were ...
      Universidad Nacional de Colombia Revistas electrónicas UN Dyna.