Search results for "Light"

Anomalous electrical parameters improvement in Ruthenium DSSC

2018

. In this work, we present a series of measurements carried out on Ruthenium-based Dye Sensitized Solar Cells (DSSCs) after the application of different external electrical field values. Such measurements have been performed both in the dark and by illuminating the sample with sunlight emitted by a solar simulator (AM1.5G spectrum with a power irradiance of 1000 W/m2). Our results demonstrate that the initial electrical bias field modifies in both cases the behavior of the cell in terms of an anomalous improvement of the main electrical parameters.

Anomalous performance enhancement effects in Ruthenium-based Dye Sensitized Solar Cells

2017

Dye Sensitized Solar Cells (DSSCs) are nowadays more and more employed since they present lower production costs than traditional silicon photovoltaic devices. An interesting phenomenon affecting such devices consists in the fact that current density-voltage (J-V) characteristic can depend on the history of the cell prior to the measurement, which often can be assimilated to an anomalous hysteresis effect. In this work, we study such phenomenon on Ruthenium-based DSSCs through a series of measurements performed after applying different values of external electrical field to the cell. The measurements have been carried out both under simulated sunlight (AM1.5G - 1000 W/m2) and in the dark. W…

Nouvelle Méthode di Jean-Jacques Lequeu. Ridisegno, analisi grafica e rilettura critica

2021

Nel mese di luglio del 1825, l’architetto-disegnatore Jean-Jacques Lequeu (Rouen 1757-Parigi 1826) confeziona gran parte dei lavori di una vita trascorsa al tavolo da disegno per donarli alla Biblioteca del Re (oggi Biblioteca Nazionale di Francia) appena un anno prima di spegnersi nel suo appartamento di Parigi al numero 33 di rue Saint-Sauveur. Da quel momento il gruppo di disegni appartenuti all’architetto normanno costituirà una delle collezioni più eterogenee e ricche di contenuti di tutto il département des estampes et de la photographie, dove oggi sono custoditi. Di questa insolita raccolta fanno parte alcuni volumi manoscritti corredati da tavole magistralmente acquerellate – come q…

El cine de ciencia ficción en las clases de ciencias de enseñanza secundaria (I). Propuesta didáctica

2015

Este trabajo presenta un ejemplo de actividades para poder trabajar en el aula con cine de ciencia ficción y documentales de divulgación científica. Estas actividades están dirigidas a la adquisición y/o mejora de los conceptos de luz y sonido, gravedad, y a la mejora de la imagen que los alumnos puedan tener de la ciencia, los científicos y la influencia de la ciencia en el futuro. Por otro lado, se presentan los resultados de valoración que, de estas actividades y su realización en el aula han hecho los alumnos con los que se han trabajado y profesores a las que se les han presentado.

Active lighting applied to three dimensional reconstruction of specular metallic surfaces by polarization imaging

2005

This thesis deals with a new automated tridimensional inspection system for specular metallic surfaces, based on polarization analysis. We first present an extension of the ‘Shape from Polarization' method for dielectric to metallic surfaces. After being reflected, an unpolarized light wave becomes partially linearly polarized, depending on the surface normal and on the refractive index of the media it impinges on. Hence, by measuring the polarization parameters of the reflected light, the surface normals are computed. The ambiguity concerning the normals orientation is solved here with a new active lighting system. Then, we describe and compare numerical methods for reconstructing the trid…

Live imaging of developmental processes in a living meristem of Davidia involucrata (Nyssaceae).

2014

Morphogenesis in plants is usually reconstructed by scanning electron microscopy and histology of meristematic structures. These techniques are destructive and require many samples to obtain a consecutive series of states. Unfortunately, using this methodology the absolute timing of growth and complete relative initiation of organs remain obscure. To overcome this limitation, an in vivo observational method based on Epi-Illumination Light Microscopy (ELM) was developed and tested with a male inflorescence meristem (floral unit) of the handkerchief tree Davidia involucrata Baill. (Nyssaceae). We asked whether the most basal flowers of this floral unit arise in a basipetal sequence or, altern…

Using the Electronics Development Advantage in Creating a Buzz for the Airline Passengers

2013

More and more airlines are trying to show their customers their ability to understand their needs, the market trends and the importance of technology in their lives. In response to the rapid development of the consumer electronics, the airline companies focus their attention on offering their customers the possibility to book a flight or check-in using a smartphone, spend time watching movies or be connected to the internet during the flight. Customers search for airlines who are more ”tech-geek” and opened to new technologies, which allows them to rate the airline companies through apps or connect more often with the airline through social-media. Technology has become an important part in …

Chemical and physical characterization of thermal aggregation of model proteins modulated by zinc(II) and copper(II) ions

2016

BACKGROUND: Metal ions are implicated in protein aggregation processes of several neurodegenerative pathologies, where the protein deposition occurs, and in the biotechnology field like the food technology where many processes in food manufacturing are based on thermal treatments. OBJECTIVE: The influence of Cu2+ or Zn2+ ions on the thermal aggregation process of Bovine beta-lactoglobulin (BLG) and Bovine Serum Albumin (BSA), two protein models, was studied with the aim of delineating the role of these ions in the protein aggregation kinetics and to clarify the related molecular mechanisms. METHODS: The protein structure changes were monitored by Raman spectroscopy, whereas the aggregate gr…

2017

Abstract. Proteins can be nitrated by air pollutants (NO2), enhancing their allergenic potential. This work provides insight into protein nitration and subsequent decomposition in the presence of solar radiation. We also investigated light-induced formation of nitrous acid (HONO) from protein surfaces that were nitrated either online with instantaneous gas-phase exposure to NO2 or offline by an efficient nitration agent (tetranitromethane, TNM). Bovine serum albumin (BSA) and ovalbumin (OVA) were used as model substances for proteins. Nitration degrees of about 1 % were derived applying NO2 concentrations of 100 ppb under VIS∕UV illuminated conditions, while simultaneous decomposition of (n…

Metal ions modulate thermal aggregation of betalactoglobulin: a join chemical and physical characterization

2014

Abstract Molecular basis of the role played by Cu 2 + and Zn 2 + ions during the thermal aggregation processes of beta-lactoglobulin (BLG) was studied by using a joint application of different techniques. In particular, Raman spectroscopy was very useful in identifying the different effects caused by the two metals at molecular level (i.e. changes in His protonation state, disulfides bridge conformation, and micro-environment of aromatic residues), evidencing the primary importance of the protein charge distribution during the aggregation process. Both metal ions are able to act on this factor and favor the protein aggregation, but Zn 2 + is able to alter the natural conformational state of…