Search results for "Volt"
showing 10 items of 2187 documents
L’apprendimento capovolto all'Università per lo sviluppo delle soft skills.
2018
L’obiettivo della ricerca è stato sperimentare una metodologia formativa con l‘utilizzo della flipped. L’intervento formativo ha permesso ai 236 studenti coinvolti di potenziare le quattro soft skills (creatività, capacità critica, comunicazione, collaborazione). L’intervento sperimentale è stato realizzato con un piano quasi sperimentale a gruppo unico, accostando metodi quantitativi e qualitativi. È stato possibile raccogliere dati e informazioni più dettagliate sui processi attivati e sugli attori, di seguire e definire in modo più analitico il percorso, le attività e le azioni effettivamente progettate realizzate. L’efficacia formativa dell’azione sperimentale è stata misurata attravers…
Reconstrucció del paisatge rural i urbà d'Almenara i La Llosa entre els segle XIII al XVI
2023
La tesi titulada «Reconstrucció del paisatge rural i urbà d'Almenara i La Llosa entre els segles XIII-XVI», aprofundeix en l'evolució del paisatge cultural d'ambdós municipis i l'estudi de la seua població. Amb la finalitat de valorar els béns culturals municipals d'aquest període i destacar-ne la rellevància i les funcions en el passat. Cosa que possibilita una millor acceptació en el manteniment i en el respecte d'aquests béns en la societat actual. El paisatge constitueix una realitat dinàmica, ja que és resultat de processos ambientals, socials i culturals que s'han succeït al llarg del temps en el territori. Aquests processos estan marcats per les maneres de vida, les polítiques, les a…
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…
Enhanced Thin-Film Transistor Performance by Combining 13,6-N-Sulfinylacetamidopentacene with Printed PEDOT:PSS Electrodes
2011
Bottom-contact/bottom-gate organic thin-film transistors (OTFTs) are fabricated using a soluble pentacene precursor (13,6-N-sulfinylacetamidopentacene; SAP) and inkjet printed PEDOT:PSS electrodes on bare SiO2 dielectrics. Saturation mobility, Ion/Ioff ratio, and threshold voltage parameters, respectively, of 0.27 cm2 V−1 s−1, 105, and −4.25 V were measured under ambient conditions after the thermal conversion of SAP to pentacene in 100 μm long channel OTFT devices. The results obtained by the above solution approach are comparable to that of vapor-phase grown pentacene-based OTFTs with photolithographic gold contacts and organic buffer layers and/or inorganic injection layers. The present …
On the physicochemical properties of pyridohelicenes.
2014
A comprehensive study on the physicochemical properties of a series of mono- and diaza[5]helicenes as well as mono- and diaza[6]helicenes is reported. Through the use of both computational and experimental methods, these helically chiral pyridohelicenes with the nitrogen atom(s) in various positions are characterised according to their inversion barriers, protonation constants and redox potentials. By using DFT calculations, kinetic measurements, UV/Vis titrations, cyclic voltammetry and EPR spectroscopy, a self-contained picture of their behaviour under conventional treatment by heat, acids and oxidising/reducing agents is provided.
Electrochemical characterization of cobalt cordierites attached to paraffin-impregnated graphite electrodes
2004
The electrochemistry of α, β and μ cobalt-containing cordierites (Co2Al4Si5O18) attached to paraffin-impregnated graphite electrodes has been studied by linear scan and cyclic voltammetries in HCl+NaCl and NaOH electrolytes. This electrochemistry is compared with that of vitreous cobalt cordierite, cobalt(II) oxide and cobalt spinel aluminate (CoAl2O4), the two last taken as reference materials. Electrochemical processes involve the site-characteristic reduction of Co(II) species to cobalt metal near to −0.5 V vs. SCE and their oxidative dissolution near +0.3 V, accompanied by solid state interconversion between Co(II) and Co(III) at potentials above +0.45 V. Cordierite-modified electrodes …
Nanopore charge inversion and current-voltage curves in mixtures of asymmetric electrolytes
2018
[EN] We consider the screening of the negative charges (carboxylic acid groups) fixed on the surface of a conical-shaped track-etched nanopore by divalent magnesium (Mg2+) and trivalent lanthanum (La3+). The experimental current (I)-voltage (V) curves and current rectification ratios allow discussing fundamental questions about the overcompensation of spatially-fixed charges by multivalent ions over nanoscale volumes. The effects of charge inversion or reversal on nanopore transport are discussed in mixtures of asymmetric electrolytes (LaCl3 and MgCl2 with KCl). In particular, pore charge inversion is demonstrated for La3+ as well as for mixtures of this trivalent ion at low concentrations …
Synthesis, Characterization, and Cu(2+) Coordination Studies of a 3-Hydroxy-4-pyridinone Aza Scorpiand Derivative.
2016
The synthesis, acid-base behavior, and Cu(2+) coordination chemistry of a new ligand (L1) consisting of an azamacrocyclic core appended with a lateral chain containing a 3-hydroxy-2-methyl-4(1H)-pyridinone group have been studied by potentiometry, cyclic voltammetry, and NMR and UV-vis spectroscopy. UV-vis and NMR studies showed that phenolate group was protonated at the highest pH values [log K = 9.72(1)]. Potentiometric studies point out the formation of Cu(2+) complexes of 1:2, 2:2, 4:3, 1:1, and 2:1 Cu(2+)/L1 stoichiometries. UV-vis analysis and electrochemical studies evidence the implication of the pyridinone moieties in the metal coordination of the 1:2 Cu(2+)/L1 complexes. L1 shows …
Investigation of Activities for Pt-M Bimetallic Nanoparticles Catalysts on the Oxygen Reduction Reaction
2015
Bi-metallic Pt3Ni/C and Pt3Co/C electrocatalysts were successfully synthesized by a solvent free chemical vapour deposition method with a narrow particle size distribution. The results showed that the electrochemical surface area was increased by adding the additional Ni or Co to a pure Pt catalyst. Pt3Ni/C catalyst exhibited a significant enhancement of oxygen reduction reaction activity. The catalysts were characterized by EDS, XRD, HRTEM and electrochemical activity was determined using cyclic voltammetry.
Accelerated Light-Induced Defect Transformation Study of Elkem Solar Grade Silicon
2012
AbstractSolar cells made of silicon feedstock from a metallurgical route must qualify not only the initial efficiency, but must also be comparable to the solar cells made from reference polysilicon on the spectral response after light induced degradation. A detailed comparative study of light induced defects and its impact on cell performance is necessary for both materials. We have studied accelerated light induced degradation (ALID) defect transformation for Elkem Solar Silicon and polysilicon solar cells by selecting wafers from different positions from respective silicon bricks. Active boron-oxygen complexes and iron ions in multicrystalline silicon solar cells have been analyzed, and t…