Selección de métodos estadísticos para la interpretación de intercomparaciones en ensayos de áridos finos

El objeto de este proyecto es seleccionar los métodos estadísticos adecuados para el tratamiento de los resultados obtenidos en un ejercicio de intercomparación para ensayos de áridos para construcción con el fin de cumplir la normativa para dicho ejercicio. Los ensayos estudiados son: - Ensayo Azul de Metileno - Equivalente de arena - Contenido total en azufre - Contenido en humus - Reactividad álcali-carbonato Los criterios aplicables para el desarrollo de los trabajos son los exigidos por la Entidad Nacional de Acreditación (ENAC) para laboratorios acreditados conforme a la Norma UNE-EN ISO/IEC 17025 y para proveedores acreditados conforme a la Norma UNE-EN ISO/IEC 17043. ABSTRACT: The purpose of this Project is to select appropriate statistical methods for the treatment of the results obtained from an intercomparison exercise for testing of aggregates for construction with the target of comply the rules for this exercise. The studied assays are: - Methylene Blue Assay - Sand equivalent - Total Sulfur Content - Humus content - Alkali-carbonate reactivity The criteria for the development of the work are those required by the National Accreditation Body (ENAC) for laboratories accredited in accordance with the UNE-EN ISO / IEC 17025 and for suppliers in accordance with the UNE-EN ISO / IEC 17043.

Sol-gel TiO2 nanoparticles prompt photocatalytic cement for pollution degradation

TiO2 nanoparticles (TiO2NPs) prepared by the sol–gel method have been incorporated to cement paste with the aim of creating a photocatalytic system capable of compensating, through degradation of hazardous molecules, the envi- ronmental impact associated to the production of the clinker. Doping was carried out at different mass ratios with TiO2NPs precursor solutions within a fresh ce- ment paste, which was then characterized using scanning electron microscopy (SEM). The photocatalytic performance was evaluated by the degradation of Methylene Blue (MB) using a 125W UV lamp as irradiating source. Main cement properties such as hydration degree and C-S-H content are affected by TiO2NPs doping level. Cement containing TiO2NPs exhibited an increasing photocatalytic activity for increasing doping, while the pure cement paste control could hardly degrade MB. The kinetics of the system where also studied and their second order behavior related to microstructural aspects of the system.

Growth and characterization of InGaN/GaN quantum dots for violet/blue applications

We report on plasma-assisted molecular beam epitaxy growth and characterization of InGaN/GaN quantum dots (QDs) for violet/blue applications.

Electrooptic effect in cholesteric blue phases with small positive dielectric anisotropy

An electrooptic effect in the blue phase of the cholesteric mixture S811-and the nematic mixture N5 is reported. To demonstrate this effect ac voltages (ƒ = 1000 Hz) between 0 and 150 νwere applied. Wavelength shifts of 70 nm were obtained.

Optical behaviour of cholesteric blue phases in electric fields

The optical behaviour of cholesteric mixtures of negative dielectric anisotrony under electric fields is reported. A mixture of S 311~ (31.35 %) + N 5 was employed. AC voltages (f = 1000 Hz) betweeen 0 and 150 volts were applied. Cells 23 micron thick, with internal SnO2 electrodes, were used.

Light-Emitting-Diodes based on ordered InGaN nanocolumns emitting in the blue, green and yellow spectral range

The growth of ordered arrays of InGaN/GaN nanocolumnar light emitting diodes by molecular beam epitaxy, emitting in the blue (441 nm), green (502 nm), and yellow (568 nm) spectral range is reported. The device active region, consisting of a nanocolumnar InGaN section of nominally constant composition and 250 to 500 nm length, is free of extended defects, which is in strong contrast to InGaN layers (planar) of similar composition and thickness. The devices are driven under pulsed operation up to 1300 A/cm2 without traces of efficiency droop. Electroluminescence spectra show a very small blue shift with increasing current, (almost negligible in the yellow device) and line widths slightly broader than those of state-of-the-art InGaN quantum wells.

Infiltration of a photonic crystal fiber with cholesteric liquid crystal and blue phase

Photonic crystal fibers (PCF) have been selectively filled with a cholesteric liquid crystal (ChLC) with special interest in the blue phase (BP) of the liquid crystal. It has been observed thermal tuning of the guided light in the visible region. A dramatically enhance appears when the phase of the liquid crystal changes from cholesteric to blue phase I (BPI). When a thermal range of the blue phase I is achieved, no changes are observed while increasing temperature from BPI through BPII and to the isotropic phase.