Now showing items 1587-1606 of 1620

    • Validating the University of Delaware’s precipitation and temperature database for northern South America 

      Santos-Gómez, José David; Fontalvo-García, Juan Sebastián; Giraldo Osorio, Juan Diego
      Vast sections of the planet face either a dearth of ground-based weather stations or are hampered by the poor quality of those in service. In response, researchers are forced to turn to climate field databases, as they ...
      Universidad Nacional de Colombia Revistas electrónicas UN Dyna. 
    • Valorization of residues from refining of used vegetable oils 

      Hidalgo-Barrio, Dolores; Gómez-Rincón, Marta; Aguado-Pesquera, Alicia; Martín-Marroquín, Jesús María; Sastre-García, Emilia
      This study investigates the advantages of two-phase anaerobic digestion for treating a mixture (1/5 v/v) of used vegetable oils processing wastes and pig manure using two semi-continuous digesters operated at mesophilic ...
      Universidad Nacional de Colombia Revistas electrónicas UN Dyna. 
    • Valorization of vinasse as binder modifier in asphalt mixtures 

      Martínez Echevarría Romero, María José; García Travé, Gema; Rubio Gámez, María Carmen; Moreno Navarro, Fernando; Pérez Mira, Domingo
      The reutilization of waste generated by industrial processes has become a majorenvironmental objective in scientific and technical research. In the construction sector, there is a broad range of techniques for the exploitation ...
      Universidad Nacional de Colombia Revistas electrónicas UN Dyna. 
    • Variables relevantes para la medición de la calidad percibida del servicio bancario 

      Berdugo Correa, Carmen Regina; Barbosa Correa, Rodrigo Alberto; Prada Angarita, Lina Margarita
      El estudio de la calidad percibida de los servicios ha sido ampliamente estudiado pero poco aplicado en el sector bancario por lo cual despierta gran interés por parte de las instituciones prestadoras del servicio e ...
      Universidad Nacional de Colombia Revistas electrónicas UN Dyna. 
    • Variation in risk category in methods of calculation of the modified fire load density 

      Cadete-Pires, Cristina Maria Paulo; De Carvalho-Veiga, Rui António; Simões-Miguel, Maria Isabel
      The management of fire safety in buildings is conducted in accordance with the type of use-risk category (Building occupancy code). For Building type XI "libraries and archives" and XII "industrial, workshops and warehouses", ...
      Universidad Nacional de Colombia Revistas electrónicas UN Dyna. 
    • Variation of technological properties of field natural rubber lattices from Hevea brasiliensis clones and natural rubber-based compounds 

      Giraldo-Vásquez, Diego Hernán; Velásquez-Restrepo, Sandra Milena
      Natural rubber (NR) is a widely used biopolymer, but the variability of its properties is a great disadvantage. In this work, variation during a 6-month period of total solids (TSC), dry rubber (DRC), ash, volatile-matter, ...
      Universidad Nacional de Colombia Revistas electrónicas UN Dyna. 
    • Verificación de transporte de trazador radiactivo usando un coeficiente funcion del tiempo en cauces naturales. 

      Constain Aragón, Alfredo José
      Actualmente los trazadores conservativos se usan en estudios hídricos pues la información obtenida es variada y precisa, contribuyendo al entendimiento de la dinámica del flujo. Sin embargo, simultáneamente se encuentran ...
      Universidad Nacional de Colombia Revistas electrónicas UN Dyna. 
    • Verification of the vibrational theoretical assignment of the DADP using isotopic labelling 

      Espinosa-Fuentes, Eduardo Antonio; Meza-Fuentes, Edgardo; Colpas-Castillo, Fredy; Castro-Suarez, John R.; Chiquillo-Correa, Gilberto; Mora, Malka
      This work deals with the comparison of the theoretical assignment of the DADP vibrational spectrum with the experimental displacements by isotopic labeling. For this, the DADP-C4 and DADP-C2 isotopomers were synthesized ...
      Universidad Nacional de Colombia Revistas electrónicas UN Dyna. 
    • Vertical well pressure and pressure derivative analysis for bingham fluids in homogeneous reservoirs 

      Martínez, Javier Andrés; Escobar Macualo, Freddy Humberto; Montealegre, Matilde
      This paper presents a technique for interpreting the behavior of pressure and pressure derivative for a Bingham-type fluid in a homogeneous reservoir drained by a vertical well using the TDS technique, by observing the ...
      Universidad Nacional de Colombia Revistas electrónicas UN Dyna. 
    • Viabilidad de la extracción de carbones a cielo abierto. caso mina la margarita 

      Veloza, Julia; Molina, Jorge; Mejia, Humberto
      Este artículo analiza la viabilidad, planeamiento y diseño de una nueva explotación a cielo abierto de carbón en la mina La Margarita S.A., con recursos carboníferos superficiales calculados en 440.139,7 ton. Se logró ...
      Universidad Nacional de Colombia Revistas electrónicas UN Dyna. 
    • Viability of probiotic bacteria Bacillus Polymyxa, Bacillus Megaterium and Lactobacillus Delbruekii subsp. bulgaricus microencapsulated under the spray-drying technique 

      De Araujo-Uribe, Natalia; Ruiz-Villadiego, Orlando Simón; Montoya-Campuzano, Olga Inés; Ramírez-Gutiérrez, Luz Adriana
      Most microorganisms that are considered as probiotics have received much attention in recent scientific research, supporting their important role in improving bowel function in both human and animal health. Probiotics have ...
      Universidad Nacional de Colombia Revistas electrónicas UN Dyna. 
    • Vigas de madera laminada Glulam reforzadas con pletinas metálicas dentadas 

      Cañola, Hernán Darío; Echavarría, César; Echavarría, Beatriz
      En este artículo se estudian las propiedades mecánicas de vigas de madera laminada Glulam reforzadas con pletinas metálicas dentadas. Se fabricaron y analizaron experimentalmente 2 grupos de vigas: 30 vigas de madera ...
      Universidad Nacional de Colombia Revistas electrónicas UN Dyna. 
    • Vinasse treatment by coupling of electro-dissolution, heterocoagulation and anaerobic digestion 

      Paz-Pino, Olga Lucía; Barba-Ho, Luz Edith; Marriaga Cabrales, Nilson
      The distillery vinasse is the most important liquid effluent of the ethanol production process and it is characterized by a high chemical oxygen demand (COD) and high biochemical oxygen demand (BOD); besides its acid pH ...
      Universidad Nacional de Colombia Revistas electrónicas UN Dyna. 
    • Viscoelastic behavior of yellow pitahaya treated with 1-MCP 

      Torres Valenzuela, Laura Sofia; Ayala-Aponte, Alfredo Adolfo; Serna, Liliana
      Foods may have both solid and liquid properties, and are described as viscoelastic products. Knowledge on such viscoelastic features is very useful for quality control and/or food stability. The purpose of this work was ...
      Universidad Nacional de Colombia Revistas electrónicas UN Dyna. 
    • Viscosity and viscometric properties of glycine in aqueous solutions of sodium thiosulfate pentahydrate (na2s2o3 .5h2o) at different temperatures 

      Páez-Meza, Manuel Silvestre; Alvarino-Bettín, Gustavo Manuel; Cantero-López, Plinio de los Santos
      Flowing times of Glycine in aqueous solutions Sodium Thiosulfate Pentahydrate (0.01-2.0 mol kg-1) using an AMVn Anton Paar viscometer at temperatures of (283.15; 288.15; 293.15; 298.15; 303.15; 308.15, 313.15 and 318.15) ...
      Universidad Nacional de Colombia Revistas electrónicas UN Dyna. 
    • Vías para la competitividad 

      López A., Jose Hilario
      Universidad Nacional de Colombia Revistas electrónicas UN Dyna. 
    • Voltage Regulation in a Power Inverter Using a Quasi-Sliding Control Technique 

      Toro-García, Nicolás; Garcés-Gómez, Yeison Alberto; Hoyos-Velasco, Fredy Edimer
      This paper shows the behavior of a three-phase power converter with resistive load using a quasi-sliding and a chaos control techniques for output voltage regulation. Controller is designed using Zero Average Dynamic (ZAD) ...
      Universidad Nacional de Colombia Revistas electrónicas UN Dyna. 
    • Voltage sag assessment using an extended fault positions method and Monte Carlo simulation 

      Sagre, Jorge Washington; Candelo, John Edwin; Montaña Chaparro, Johny Hernán
      In this article, we propose an extended fault positions method combined with the Monte Carlo method to evaluate voltage sags. The distribution function SARFI is obtained by taking into account the randomness of (i) location ...
      Universidad Nacional de Colombia Revistas electrónicas UN Dyna. 
    • Voltage stability analysis taking into account a shunt connected device based on power electronics 

      Escobar Álvarez, Hernán Darío; Correa Gutiérrez, Rosa Elvira; Ramírez Arredondo, Juan Manuel
      In this paper the power system voltage stability problem is analyzed with active power–voltage (PV) curves, as a voltage compensator is introduced. The PV curves’ shape has been a subject of great concern, especially when ...
      Universidad Nacional de Colombia Revistas electrónicas UN Dyna. 
    • Vulnerability Assessment of Power Systems to Intentional Attacks using a Specialized Genetic Algorithm 

      Agudelo, Laura; López-Lezama, Jesús María; Muñoz Galeano, Nicolás
      A specialized genetic algorithm applied to the solution of the electric grid interdiction problem is presented in this paper. This problem consists in the interaction of a disruptive agent who aims at maximizing damage of ...
      Universidad Nacional de Colombia Revistas electrónicas UN Dyna.