Search results for "surface"
showing 10 items of 9345 documents
Indo-French High-resolution Thermal Infrared Space Mission for Earth Natural Resources Assessment and Monitoring -Concept and Definition of TRISHNA
2019
The Indian and French Space Agencies, ISRO and CNES, have conceptualized a space-borne Thermal Infrared Reflectance (TIR) mission, TRISHNA (Thermal infRared Imaging Satellite for High-resolution Natural Resource Assessment). The primary design drivers of TRISHNA are the monitoring of (i) terrestrial water stress and use, and of (ii) coastal and continental water. A suit of four TIR bands and six optical bands is planned. The TIR bands will be centred at 8.6 μm, 9.1 μm, 10.3 μm and 11.5 μm to provide noon-night global observations at 57m nadir resolution over land and coastal regions. The field of view (FOV) is ±34° and the orbit of 761&thin…
Plasmonic Stripes in Aqueous Environment Co-Integrated With Si3N4 Photonics
2018
We demonstrate the design, fabrication, and the experimental characterization of gold-based plasmonic stripes butt-coupled with low-pressure-chemical-vapor-deposition (LPCVD)-based Si3N4 waveguides for the excitation of surface-plasmon-polariton (SPP) modes in aqueous environment. Plasmonic gold stripes, in aqueous environment, with cross-sectional dimensions of 100 nm × 7 μm were interfaced with 360 nm × 800 nm Si3N4 waveguides cladded with low-temperature-oxide, exploiting linear photonic tapers with appropriate vertical (VO) and longitudinal (LO) offsets between the plasmonic and photonic waveguide facets. An interface insertion loss of 2.3 ± 0.3 dB and a plas…
Fabrication-friendly polarization-sensitive plasmonic grating for optimal surface-enhanced Raman spectroscopy
2020
Plasmonic nanostructures are widely utilized in surface-enhanced Raman spectroscopy (SERS) from ultraviolet to near-infrared applications. Periodic nanoplasmonic systems such as plasmonic gratings are of great interest as SERS-active substrates due to their strong polarization dependence and ease of fabrication. In this work, we modelled a silver grating that manifests a subradiant plasmonic resonance as a dip in its reflectivity with significant near-field enhancement only for transverse-magnetic (TM) polarization of light. We investigated the role of its fill factor, commonly defined as a ratio between the width of the grating groove and the grating period, on the SERS enhancement. We des…
Cambio de percepción de los niños de preescolar sobre su ambiente, mediante una intervención educativa con enfoque local.
2015
La investigación se desarrolla con 300 infantes de doce centros escolares de preescolar en cinco comunidades aledañas a los Manglares y Humedales de Tuxpan. El objetivo fue determinar si una intervención educativa cambia la percepción sobre su medio. Se realiza un diagnóstico solicitando a los pequeños que elaboraran un dibujo bajo el título ¿Cómo es mi medio ambiente?. Se diseña e implementa una intervención educativa pertinente al contexto y alineada con el currículum Programa de Estudios 2011/ Preescolar, específicamente con el campo formativo de Exploración y Conocimiento del mundo, fomentando una actitud reflexiva sobre la importancia del aprovechamiento adecuado de los recursos natura…
OBSTÁCULOS AL APRENDIZAJE DEL CONCEPTO ESTRUCTURANTE EVOLUCIÓN BIOLÓGICA
2014
Se contrastaron los obstáculos en el aprendizaje del concepto evolución biológica reportados en publicaciones especializadas en la enseñanza de las ciencias, con losen la implementación de un juego para enseñar evolución por selección natural. Lo anterior, se realizó mediante la revisión de antecedentes que permitieron identificar los obstáculos encontrados por otros investigadores y la puesta en marcha de la propuesta didáctica que posibilitó identificar y superar algunos de los mismos. Existen múltiples factores que dificultan la comprensión de la evolución biológica, componentes culturales, iconografía inapropiada, insuficiente preparación de los profesores, estrategias didácticas inade…
Valoración de los Proyectos de Grado sobre Educación Ambiental en la Universidad, Aplicando la Hipótesis de Progresión
2015
Este trabajo aplica la hipótesis de progresión como metodología para la valoración de los proyectos de grado de los estudiantes en Educación Ambiental en la Universidad.Se han analizado, los proyectos realizados por los alumnos de la licenciatura en Biología y Educación Ambiental, en la Universidad del Quindío, Colombia. Cuyo objetivo tiene la formación de profesores para los diferentes niveles educativos. La hipótesis de progresión permite valorar el cambio conceptual presentado en los proyectos de grado no como un proceso puntual sino como un proceso de evolución de los contenidos.La investigación muestra que los Proyectos fin de grado de los estudiantes de Biología y educación A…
Corrigendum to "Experimental study of the role of physicochemical surface processing on the IN ability of mineral dust particles" published in Atmos.…
2011
Atmospheric Chemistry and Physics, 11 (22)
Vortex shape in unbaffled stirred vessels: experimental study via digital image analysis
2011
There is a growing interest in using unbaffled stirred tanks for addressing certain processing needs. In this work, digital image analysis coupled with a suitable shadowgraphy-based technique is used to investigate the shape of the free-surface vortex that forms in uncovered unbaffled stirred tanks. The technique is based on back-lighting the vessel and suitably averaging vortex shape over time. Impeller clearance from vessel bottom and tank filling level are varied to investigate their influence on vortex shape. A correlation is finally proposed to fully describe vortex shape also when the vortex encompasses the impeller.
Height of water pouring effects on infiltration runs carried out in an initially wet sandy-loam soil
2017
Ring infiltration methods are widely used for field soil hydraulic characterization. Establishing factors affecting these methods is necessary to interpret the collected data. The height from which water is poured on the soil surface is known to influence infiltration in a sandy-loam soil, since low (L, height of water pouring 0.03 m) runs yielded higher infiltration rates than high (H, 1.5 m) runs in previous investigations. The impact of water pouring height on infiltration rates seems to vary with the antecedent soil water content, θi. In this investigation, height effects on infiltration were tested for an initially very wet sandy-loam soil. Two-stage infiltration runs differing by the…
Morphodynamics of river bed variation with variable bedload step length
2013
Abstract. Here we consider the 1-D morphodynamics of an erodible bed subject to bedload transport. Fluvial bed elevation variation is typically modeled by the Exner equation, which, in its classical form, expresses mass conservation in terms of the divergence of the bedload sediment flux. An entrainment form of the Exner equation can be written as an alternative description of the same bedload processes, by introducing the notions of an entrainment rate into bedload and of a particle step length, and assuming a certain probability distribution for the step length. This entrainment form implies some degree of nonlocality, which is absent from the standard flux form, so that these two express…