Search results for "MATERIALS"
showing 10 items of 29608 documents
Geological and cultural heritage: Dissemination experiences in Tuscany
2019
We report on some recent experiences of scientific dissemination activities on geomaterials carried out by a network of scientific organizations in Tuscany (Italy). The primary message we want to disseminate is that even the most "insignificant" rock (e.g., those constituting the bar or kitchen counter-tops) stores in their interior very useful information beyond the beautiful colors and their aesthetic appearance. These rocks can tell stories of very old geological periods on how they were formed. Their structures, texture and shape, as well as their chemistry and mineralogy provide clues to the reconstruction of geological events. Moreover, the rocks used in urban architecture and monumen…
Effect of Heat on the Adsorption Properties of Silica Gel
2012
Published version of an article in the journal: International Journal of Engineering and Technology. Also available from the publisher at: http://www.ijetch.org/papers/416-T886.pdf Open access. Adsorption properties of silica gel have been attributed to the surface hydroxyl groups of silica gel. Some hydroxyl groups are free standing and called free silanol groups. Some are hydrogen bonded to neighbouring silanol groups. Christy has shown that a high silanol number and a balanced concentration proportionality between these two different types of hydroxyl groups is necessary for effective adsorption of water molecules. Thermal treatment of silica gel samples alters the proportions of these g…
English teachers' perception of the purpose of a CD connected to English textbooks
2009
Vieraan kielen opiskelussa ja opettamisessa on käytetty pitkään apuvälineinä erilaisia äänitteitä. Kuitenkin vasta lähiaikoina äänitteitä on alettu käyttää myös luokkahuoneen ulkopuolella. Nykyisin monissa suomalaisissa peruskouluissa käytetään englannin kielen oppikirjoja, joissa tulee mukana myös oppilaan CD. Tämä CD on tarkoitettu oppilaan itsenäiseen käyttöön tukemaan vieraan kielen opiskelua kotona. Koska CD:n käyttö on vielä uutta, ei sitä ole tutkittukaan. Aikaisemmat tutkimukset vieraan kielen kuuntelemisesta keskittyvät lähinnä luokkahuonetilanteisiin. Vain muutama aikaisempi tutkimus mainitsee lyhyesti itsenäisen kuuntelun tärkeydestä. Siksi onkin tärkeää tutkia, mikä rooli tällä…
Influence of a Thiolate Chemical Layer on GaAs (100) Biofunctionalization: An Original Approach Coupling Atomic Force Microscopy and Mass Spectrometr…
2013
International audience; Widely used in microelectronics and optoelectronics; Gallium Arsenide (GaAs) is a III-V crystal with several interesting properties for microsystem and biosensor applications. Among these; its piezoelectric properties and the ability to directly biofunctionalize the bare surface, offer an opportunity to combine a highly sensitive transducer with a specific bio-interface; which are the two essential parts of a biosensor. To optimize the biorecognition part; it is necessary to control protein coverage and the binding affinity of the protein layer on the GaAs surface. In this paper; we investigate the potential of a specific chemical interface composed of thiolate molec…
¿Quién está buscando su mejor versión? Coaching y psicología deportiva en el proceso de terapeutización de (y desde) el golf
2020
This article asks about the expansion of psychological, therapeutic and self-enhancement ethos through the networks and devices that configures middle and upper-middle classes, and about the ways in which this process is singled out starting from the encounter between coaching and psychology paradigms with golf fans, in contemporary Argentina. The empirical materials that support the analysis have been ethnographically produced from the interaction with golf players and coaches.
Real-time smoothing of car-following data through sensor-fusion techniques
2011
Abstract Observation of vehicles kinematics is an important task for many applications in ITS (Intelligent Transportation Systems). It is at the base of both theoretical analyses and application developments, especially in case of positioning and tracing/tracking of vehicles, car-following analyses and models, navigation and other ATIS (Advanced Traveller Information Systems), ACC (Adaptive Cruise Control) systems, CAS and CWS (Collision Avoidance Systems and Collision Warning Systems) and other ADAS (Advanced Driving Assistance Systems). Modern technologies supply low-cost devices able to collect time series of kinematic and positioning data with medium to very high frequency. Even more da…
A Model for the Study of Sheath Currents in Medium Voltage Cables for Industrial Application
2020
In this paper, the implementation of a simulation model for studying the effect of cross-bonding of metallic sheaths and/or non-magnetic armor of single-core medium voltage cables in the same circuit is discussed. With the use of single-core cables, the resistive losses due to the induced circulating currents in cable sheaths or armors causes an increase of cable temperature that reduces its ampacity. In addition, the risk of electric shock due to induced voltages may be present if a person is exposed to the armor/sheath at the unbounded end. For this reason, special bonding techniques are used to significantly reduce these currents. The authors have implemented a model that could be used t…
The structural disorder of a silica network probed by site selective luminescence of the nonbridging oxygen hole centre
2011
We studied the inhomogeneous distribution of the luminescence band associated with the nonbridging oxygen hole centre in silica through site selective excitation/detection of the zero phonon line by a tunable laser source. Defects induced in the bulk of synthetic samples by γ and β exposure exhibit an increase of the inhomogeneous width from 0.071 to 0.086 eV on increasing the irradiation dose from 2 × 10(6) to 5 × 10(9) Gy. We also investigated two defect variants stabilized at the surface of the silica nanoparticles, (≡ Si-O)3 Si–O* and (≡ Si-O)2(H-O)Si-O*, whose inhomogeneous width was measured to be 0.042 eV and 0.060 eV, respectively. These results can be accounted for by the structura…
Resonance Raman of oxygen dangling bonds in amorphous silicon dioxide
2017
We investigate the origin of a resonance Raman band induced by ionizing radiation in amorphous silicon dioxide (silica glass), which can be detected under ultraviolet laser excitation. A silica sample, rich of oxygen-excess related defects, was prepared by treating some length of a pure-silica-core multimode fiber in an O2 atmosphere (at high temperature and pressure) and by irradiating it with X-rays at 10 MGy(SiO2) dose. A micro-Raman study revealed a gaussian band peaking at 896 cm−1 with a full width at half maximum of 32 cm−1, which could be detected by exciting the sample with the 325-nm line of a HeCd laser. This spectral feature is absent in the Raman spectra performed with the 442-…
Charge Transport Mechanisms in Heavy-Ion Driven Leakage Current in Silicon Carbide Schottky Power Diodes
2016
Under heavy-ion exposure at sufficiently high reverse bias voltages silicon carbide (SiC) Schottky diodes are observed to exhibit gradual increases in leakage current with increasing ion fluence. Heavy-ion exposure alters the overall reverse current-voltage characteristics of these diodes, leaving the forward characteristics practically unchanged. This paper discusses the charge transport mechanisms in the heavy-ion damaged SiC Schottky diodes. A macro model, describing the reverse current-voltage characteristics in the degraded SiC Schottky diodes is proposed. peerReviewed