Clasificación de la fracción fina de materiales para base granular provenientes de fuentes de material del municipio de Cundinamarca, a partir de su valor de azul de metileno y equivalente de arena.

Trabajo de investigaciónEn el campo de la ingeniería de pavimentos, los agregados pétreos constituyen un pilar importante en la estructura de un proyecto vial. Motivados en aumentar la durabilidad y serviciabilidad de la red vial de Cundinamarca y sus alrededores, de forma aleatoria se realizó la selección de tres fuentes de material para aplicar ensayos de clasificación de fracción fina. Esto permitió diferenciar entre las fuentes de material, los agregados para base granular que pueden ser usados. Adicionalmente, por medio del análisis de cada muestra de fuente de material, se efectuó la caracterización de los agregados por su zona de explotación.RESUMEN ABSTRACT INTRODUCCION GENERALIDADES DEL PROYECTO DE GRADO JUSTIFICACION OBJETIVOS MARCO DE REFERENCIA DISEÑO METODOLOGICO ANALISIS DE RESULTADOS CONCLUSIONES RECOMENDACIONES ANEXOSEspecializaciónEspecialista en Ingeniería de Pavimento

Interaction of nanoparticles with substrates: effects on the dipolar behaviour of the particles

In this work, we present a numerical analysis of the surface electric field of a metallic nanoparticle (either 2D or 3D) interacting with a flat substrate underneath. The influence of the distance to the substrate, particle size, the surrounding media and the substrate optical properties is analyzed as a function of the incident wavelength. We show that these are crucial factors that change the field distribution associated to the dipolar behavior of the particle. A useful parameter for illustrating the changes in the angular distribution is θmax , the angle at which the maximum of the surface electric field is located

Surface inspection by monitoring spectral shifts of localized plasmon resonances

We present a numerical study of the spectral variations of localized surface plasmon resonances (LSPR) in a 3D-probe metallic nanoparticle scanned over an inhomoegeneous dielectric surface. The possibilities for both, index monitoring and lateral resolution at nanoscale level are explored, with special attention paid to the shape of the probe and the profile of the near field underneath

Polar decomposition of the Mueller matrix: a polarimetric rule of thumb for square-profile surface structure recognition

In this research, the polar decomposition (PD) method is applied to experimental Mueller matrices (MMs) measured on two-dimensional microstructured surfaces. Polarization information is expressed through a set of parameters of easier physical interpretation. It is shown that evaluating the first derivative of the retardation parameter, δ, a clear indication of the presence of defects either built on or dug in the scattering flat surface (a silicon wafer in our case) can be obtained. Although the rule of thumb thus obtained is established through PD, it can be easily implemented on conventional surface polarimetry. These results constitute an example of the capabilities of the PD approach to MM analysis, and show a direct application in surface characterization

Spectral behavior of the linear polarization degree at right-angle scattering configuration for nanoparticle systems

We present a numerical study of the spectral evolution of the linear polarization degree at right-angle scattering configuration (PL(90º)) for two different particle systems: an isolated nanosphere and a nanodimer composed of two finite size spherical particles separated by a gap distance d. We shall focus on the influence of charge oscillation modes other than the dipolar on the linear polarization degree of the scattered light. The possibility of using this alternative parameter for characterizing nanoparticle systems and particle interaction is analyzed.We acknowledge financial support from USAITCA (US Army International Technology Center—Atlantic) under the project R&D1390-PH-01 and from the Ministry of Education of Spain under the project FIS2007-60158

Light scattering resonances in small particles with electric and magnetic properties

Lorenz–Mie resonances produced by small spheres are analyzed as a function of their size and optical properties ( ε≷0 , μ≷0 ). New generalized (μ≠1) approximate and compact expressions of the first four Lorenz–Mie coefficients ( a1 , b1 , a2 , and b2 ) are calculated. With these expressions and for small particles with various values of ε and μ, the extinction cross section (Qext) is calculated and analyzed, in particular for resonant conditions. The dependence on particle size of the extinction resonance, together with the resonance shape (FWHM), is also analyzed. In addition to the former analysis, a study of the scattering diagrams for some interesting values of ε and μ is also presented

Polar decomposition of Mueller matrices for 2D-structured surfaces

In this research, the Polar Decomposition (PD) has been applied to the Mueller matrices (MMs) of the light scattered by linear ribs of rectangular profile on a flat substrate. Although photo-lithographic technique produces a silicon surface, metallic character is acquired by sputtering with gold some of the samples. With a dual rotating compensator polarimeter the MMs are obtained by Fourier Transform analysis. The samples have been numerically modeled by using both FDTD and Extinction Theorem (ET) and MMs have been computed from the results. The scattering depends strongly on the geometry and composition of the ribs, and this sensitivity is noticed for instance in M11 element. But information offered by PD parameters is shown to be more apprehensible, like the substrate-induced depolarization or the retardance associated to the rib width.This research has been supported by the Ministry of Education of Spain under project FIS2007-60158 and by USAITCA through R&D 1390-PH-01

Computationally efficient simulation of unsteady aerodynamics using POD on the fly

Modern industrial aircraft design requires a large amount of sufficiently accurate aerodynamic and aeroelastic simulations. Current computational fluid dynamics (CFD) solvers with aeroelastic capabilities, such as the NASA URANS unstructured solver FUN3D, require very large computational resources. Since a very large amount of simulation is necessary, the CFD cost is just unaffordable in an industrial production environment and must be significantly reduced. Thus, a more inexpensive, yet sufficiently precise solver is strongly needed. An opportunity to approach this goal could follow some recent results (Terragni and Vega 2014 SIAM J. Appl. Dyn. Syst. 13 330–65; Rapun et al 2015 Int. J. Numer. Meth. Eng. 104 844–68) on an adaptive reduced order model that combines 'on the fly' a standard numerical solver (to compute some representative snapshots), proper orthogonal decomposition (POD) (to extract modes from the snapshots), Galerkin projection (onto the set of POD modes), and several additional ingredients such as projecting the equations using a limited amount of points and fairly generic mode libraries. When applied to the complex Ginzburg–Landau equation, the method produces acceleration factors (comparing with standard numerical solvers) of the order of 20 and 300 in one and two space dimensions, respectively. Unfortunately, the extension of the method to unsteady, compressible flows around deformable geometries requires new approaches to deal with deformable meshes, high-Reynolds numbers, and compressibility. A first step in this direction is presented considering the unsteady compressible, two-dimensional flow around an oscillating airfoil using a CFD solver in a rigidly moving mesh. POD on the Fly gives results whose accuracy is comparable to that of the CFD solver used to compute the snapshots

Directionality in scattering by nanoparticles: Kerker’s null-scattering conditions revisited

Since the first studies made by Kerker in the 1970s stating the conditions for null light scattering in certain directions by particles, such conditions have remained unquestioned. The increasing interest in scattering directionality by tuning the optical properties of materials demands a new analysis of this problem. In addition, as has been shown recently, one of Kerker’s statements does not comply with the optical theorem. We propose corrected expressions for the null-scattering conditions that satisfy the optical theorem

Dispositivo óptico de aumento para cámara oscura

Solicitud: 202231511 (16.09.2022)Nº Pub. de Solicitud: ES1295930U (22.12.2022)Nº de Modelo de Utilidad: ES1295930Y (15.03.2023