Search results for "thermal [radiation mechanism]"
showing 10 items of 2571 documents
Facile synthesis and characterization of monocrystalline cubic ZrO2 nanoparticles
2007
Abstract Crystalline ZrO2 nanoparticles were prepared from zirconium isopropoxide by slow hydrolysis and subsequent hydrothermal treatment of solutions containing various amounts of sodium hydroxide at 180 °C. Whereas moderately basic solutions lead to the formation of nanoparticles of monoclinic ZrO2 with plate-like morphology, and nanoparticles of the cubic ZrO2 high-temperature polymorph with diameters of approx. 5 nm were obtained from strongly basic solutions. The morphology, structure and properties of as-synthesized nanoparticles were characterized using HRTEM, XRD, Raman spectroscopy, UV–vis, PL spectroscopy and BET measurements. The formation of both, the monoclinic and the cubic p…
Citohroma c peroksidāzes loma Zymomonas Mobilis termiskā un oksidatīvā stresa noturībā
2020
Lai pētītu Zymomonas mobilis citohroma c peroksidāzes ietekmi uz celmu termiskā un oksidatīvā stresa noturību, izveidots plazmīdas konstrukts ar ccp gēnu. Ar to transformēts Zymomonas mobilis celms Zm6. Kultivējot jauniegūto celmu, izejas celmu un iepriekš izveidotus mutantus celmus ar inaktivētu citohroma c peroksidāzi un celmu ar inaktivētu katalāzi, salīdzināta celmu izturība oksidatīvā un termālā stresa apstākļos. Audzēšanas eksperimentos parādīts, ka pārbaudītajos mikroaerofīlajos apstākļos citohroma c peroksidāzes aizsargājošā funkcija nav tik izteikta kā aerobos apstākļos. Mikroaerofīlos apstākļos aizsardzību pret reaktīvajām skābekļa formām primāri nodrošina katalāze
Uses and limits of thermal indices: the case of Sahel
2015
International audience; Our main goal here is to analyse extreme heat waves (HWs) in the Sahel (13°N-18°N; 16°W-30°E), using different thermal indices. In the ACASIS project funded bythe French “Agence Nationale de la Recherche”, HWs analyses are characterized forthe first time during the hottest season in the Sahel, using the Global Summary of theDay (GSOD) synoptic observations during April-May-June 1973-2013. Such extremehigh temperatures are usually defined by 3 criteria: 1/ Their low probability ofoccurrence: less than the 10% of the days. The use of absolute thresholds,associated with heat budget and physiological impacts, could be an alternative(Seneviratne et al., 2012). 2/ Their in…
Syntheses of TiO2 anatase nanocrystals with controlled size distribution. Influence of the crystallites size on the Raman spectrum and investigation …
2006
The determination of the size and the size distribution of anatase TiO2 nanopowders using Raman spectroscopy is presented. Several synthesis methods (soft chemistry, water-in-oil microemulsion, continuous hydrothermal synthesis) are used in order to control the size (from 3 to 20 nm), shape, phase and size distribution. The shift and width of the anatase Eg peak are often used to obtain the nanoparticles size. Homever, this peak is also sensitive to nonstoichiometry and others parameters. Low-frequency Raman scattering does not suffer from this problem. Size distibutions obtained by Raman spectroscopy and MET micrographs are compared. Finally, in situ Raman spectroscopy is used to study the…
Gelled Electrolyte Containing Phosphonium Ionic Liquids for Lithium-Ion Batteries
2018
In this work, new gelled electrolytes were prepared based on a mixture containing phosphonium ionic liquid (IL) composed of trihexyl(tetradecyl)phosphonium cation combined with bis(trifluoromethane)sulfonimide [TFSI] counter anions and lithium salt, confined in a host network made from an epoxy prepolymer and amine hardener. We have demonstrated that the addition of electrolyte plays a key role on the kinetics of polymerization but also on the final properties of epoxy networks, especially thermal, thermo-mechanical, transport, and electrochemical properties. Thus, polymer electrolytes with excellent thermal stability (>
The infrared thermography control of the laser welding of amourphous polymers
2008
International audience; In laser welding technique, a real-time control of temperature distribution inside the irradiated materials is essential when attempting to optimize the process. For all laser welding methods that operate by the transmission principle, the difficulty of recording the developed temperature at the interface derives from the fact that materials to be welded are in contact throughout the entire process. In the present study, in order to overcome this issue, a contact-free method such the infrared thermography is used for surface temperature measurement. Corroborating this data with a numerical simulation of the temperature field evolution inside the components, an assess…
Rectifications optique et thermique générées à l'aide de jonctions tunnel planaires électromigrées
2017
The work described in this manuscrit consists in studying the optical rectification within plasmo-electronic devices. These ultra-compact optically adressed components with an ultra-fast time response induces a conversion of the incident field into a static current. The monolithically-integrated electronically optical antenna requires a detailed knowledge of nanoscale thermal and electrical transport mechanisms. This work also aims to discuss all thermal effects inherent in the optical excitation of these connected devices, in order to identify the different contributions in the generation of a photo-assisted current.
Porous architecture and thermal properties of thermal barrier coatings deposited by suspension plasma spray
2020
Abstract Besides the intrinsic low heat transfer capability of material, the thermal insulation property of thermal barrier coatings (TBCs) also relies on their microstructures. For better understanding the relationship between process parameters, porous architecture, and thermal properties of coatings, YSZ coatings were firstly manufactured by suspension plasma spray (SPS). Afterwards their total porosities were characterized by using the technique of X-ray transmission, the nano/submicro pores in those coatings were detected with Ultra-Small Angle X-ray Scattering (USAXS), and the thermal properties of coatings were measured using the laser flash method. The results indicated that: i) the…
Exposure to nanoparticles in thermal spraying - Vigilance towards the operator and the outside environment
2021
International audience; The previous survey of the French CaRPE project has shown a lack of information and showed the interest to assess the residual exposure to these particles. This paper presents the results of various sampling operations and emission analyses of plasma spraying equipment. For this purpose, different areas have been targeted, such as at the level of the emissions channeled upstream and downstream of the filtration system, at the workstation level as well as fugitive emissions. Various measurements were carried out: real-time particle size distribution, mass concentration of total suspended dust, heavy metals, sampling characterization by EDX/ MET, etc. The metallic aero…
The Piancaldoli meteorite: A forgotten primitive LL3.10 ordinary chondrite
2020
International audience; The Piancaldoli ordinary chondrite fell in northern Italy on August 10, 1968. Preliminary studies led to its classification as an LL3.4 unequilibrated ordinary chondrite. However, recent developments in classification procedures have prompted us to re‐examine its mineralogical, petrographic, spectroscopic, chemical, and isotopic features in a multi‐technique study. Raman spectra and magnetic properties indicate that Piancaldoli experienced minimal thermal metamorphism, consistent with its high bulk hydrogen content and the Cr contents of ferroan olivines in its type II chondrules. In combination with findings of previous studies, our data thus confirm the variability…