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URI permanente para esta colecciónhttp://10.0.96.45:4000/handle/11056/14725

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    Generation of potential bactericidal surfaces from aluminum via anodization
    (Laboratorio Nacional de Nanotecnología (LANOTEC) (Costa Rica), 2019) Paniagua, Sergio; Rojas-Gatjens, Esteban; Villalobos, Javier; Montes de Oca-Vásquez, Gabriela; Pereira, Reinaldo; Murillo, Luis Carlos; Jose-Roberto, Vega-Baudrit
    Bactericidal nanostructured surfaces are found in nature, developed through millions of years of evolution. Gecko skin, dragonfly wings and cicada wings possess nanoscale spikes or pillars that are able to have bactericidal action through non-chemical bactericidal methods, via impalement2 or mechanical stress3 (Fig. 1). These mechanisms offer the advantage of being more difficult for bacteria to develop resistance compared to pharmaceutical alternatives.1 An important strategy to control the spread of disease is to maintain surfaces clean to prevent secondary infection. Many high touch areas in operating rooms, factories, kitchens, and bathrooms are made of aluminum (trays, door handles, poles, tables, etc.). An aluminum surface engineered to have nanopillars could be bactericidal by mechanical means, thereby helping with prevention of spread of diseases.
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    Ítem
    Groundwater flow modeling using iMOD for Barva and Colima aquifers in the Central Valley of Costa Rica: validation of a conceptual model using tracer data
    (Universidad Nacional de Salta, 2018) Gomez Castro, Cinthya; Ball, Sheila Marie; Sanchez-Murillo, Ricardo
    A stationary numerical model of groundwater flow was developed using iMOD to better understand the recharge processes within Barva and Colima aquifers (BCS), located in the northwestern region of the Central Valley of Costa Rica. Lithological information was used to develop a conceptual model representing the complexity of the system, defined as high transmissivities, low storage capacity, and steep hydraulic gradients. Due to the lack of more detailed lithological and hydrometric data to perform robust calibrations, the system was studied by analyzing water flux dynamics using the iMOD particle tracer and water balance tools. The validation process was done by comparing the results of each simulation with the potential recharge elevation (PRE) derived from the ages of existing noble gases (tritium/helium) at different wells and springs in the system. Tracer estimations indicate a groundwater age (GWA) ranging from 2.3 to 71 years. Based on the tracer information, two hypotheses of PRE were evaluated. The first scenario (H01), with a PRE between 1,500 to 2,500 m a.s.l., and a second one (H02), with a PRE between 1,300 to 1,500 m a.s.l. Results from H01 were the most reliable: 77% of the particles dropped in the PRE were captured by the Lower Colima aquifer, with a GWA ranging from 1 to 45 years. Although the results reflect the dynamic-complex fluxes, more information is needed to understand the influence of surface water and recharge rates on groundwater levels in order to improve and calibrate the model as a reliable water management tool.