Search results for "thermal [correlation function]"
showing 10 items of 1923 documents
Helium isotope systematics of volcanic gases and thermal waters of Guadeloupe Island, Lesser Antilles
2014
Abstract The island of Guadeloupe is located in the middle of the 850 km long Lesser Antilles island arc. Present-day volcanic and geothermal activity is concentrated in two systems both located in the southwestern part of the island (Basse Terre): the La Soufriere volcanic complex and the Bouillante hydrothermal system, some 20 km to the northwest of the volcano. We report here the largest isotopic data set for helium isotopes in hydrothermal gases and waters from both systems, acquired between 1980 and 2012. 3 He/ 4 He ratios in the fumarolic gases of La Soufriere volcano have been quite homogeneous and stable over the last thirty years. The average ratio of 8.2 ± 0.2 R a confirms that th…
Carbon dioxide diffuse emission and thermal energy release from hydrothermal systems at Copahue-Caviahue Volcanic Complex (Argentina)
2015
Fil: Chiodini, Giovanni. Istituto Nazionale di Geofisica e Vulcanologia, Sezione di Bologna. Bologna, Italia. Fil: Cardellini, Carlo. Università degli Studi di Perugia, Dipartimento di Fisica e Geologia. Perugia, Italy. Fil: Lamberti, María C. Universidad de Buenos Aires. Instituto de Estudios Andinos. Buenos Aires, Argentina. Fil: Agusto, Mariano. Universidad de Buenos Aires. Instituto de Estudios Andinos. Buenos Aires, Argentina. Fil: Caselli, Alberto Tomás Universidad Nacional de Río Negro. Instituto de Investigación en Paleobiología y Geología. Río Negro. Argentina. Fil: Liccioli, Caterina. Universidad de Buenos Aires. Instituto de Estudios Andinos. Buenos Aires, Argentina. Fil: Tambure…
The Magmatic to Hydrothermal Evolution of the Intrusive Mont Saint-Hilaire Complex: Insights into the Late-stage Evolution of Peralkaline Rocks
2017
The Cretaceous Mont Saint-Hilaire complex (Quebec, Canada) comprises three major rock units that were emplaced in the following sequence: (I) gabbros; (II) diorites; (III) diverse partly agpaitic foid syenites. The major element compositions of the rock-forming minerals, age-corrected Nd and oxygen isotope data for mineral separates and trace element data of Fe-Mg silicates from the various lithologies imply a common source for all units. The distribution of the rare earth elements in clinopyroxene from the gabbros indicates an ocean island basalt type composition for the parental magma. Gabbros record temperatures of 1200 to 800 degrees C, variable silica activities between 0 center dot 7 …
Effect of explosive shallow hydrothermal vents on δ13C and growth performance in the seagrass Posidonia oceanica
2010
Summary 1. Explosive volcanic submarine activity is expected to affect seagrass communities due to sudden and dramatic changes in the physical and chemical features of sea water and sediments, with possibly large ecosystem effects. However, seagrass response to the harsh environmental conditions that arise due to explosive volcanism is as yet unexplored as it is not easy to predict when and where an eruption will occur. Here, we investigate the uptake of hydrothermal carbon within the seagrass Posidonia oceanica by the analysis of δ13C and growth rates in tissue laid down before and after an exceptional and massive hydrothermal gas release in the Aeolian Islands (Italy, Mediterranean Sea). …
Photo-thermal control of surface plasmon mode propagation at telecom wavelengths
2016
Surface plasmon polaritons (SPPs) is the promising versatile platform proposed for guiding electromagnetic waves at nanoscale dimensions. In this context dynamic control of SPPs prop- agation is of paramount importance. Thermo-optical (TO) effect is considered as an efficient technique for performing active control of plasmonic devices. Among the thermo-optical based plasmonic devices demonstrated so far TO coefficient is dominantly provided by a dielectric material on top of the metal sustaining the SPP mode, however, the role of TO properties of the metal has been rarely investigated for plasmonic applications especially at the telecom frequency ranges. Therefore, the aim of this thesis i…
Design and Test of a Thermomagnetic Motor Using a Gadolinium Rotor
2013
This paper presents a Thermomagnetic Motor, whose design of the motor is based on a thermal-magnetic coupled dynamic model, which models its magnetic as well thermal properties (magnetic permeability and thermal conductivity). The thermal processes are supposed to be influenced by the thermal conductivity, the convection and the advection. An analytical expression of the generated torque, which links this quantity to the magnetic, thermal and geometrical parameters of the generated torque is given. A design of a machine, based on this theory is proposed and the related performances are numerically simulated. An experimental verification of the performances is reported.
Automatic detection of thermal anomalies in induction motors
2021
The paper proposes a methodology based on Artificial Intelligence techniques for the automatic detection of abnormal thermal distributions in electric motors, to rapidly identify pre-faults or fault conditions. The proposed approach, applied to induction motors of different sizes, installed in waterworks plants, is based on the execution of Thermographic Non-Destructive Tests, which allow identifying abnormal operating conditions without interrupting the ordinary working conditions of the system. Thermographic images of induction motors are acquired at the installation site and with perspectives visible to the operator, which are sometimes partially obstructed. These thermographic images ar…
Thermal 1,6-Electrocyclization Reactions of Acceptor-Substituted 2,3-Divinyl-1H-indoles Yielding Functionalized Carbazoles
1990
Three new synthetic procedures for and thermal 1,6-electrocyclizations of acceptor-substituted 2,3-divinyl-1H-indoles leading to functionalizing carbazoles are described. The scope and limitations as well as some mechanistic aspects of the methodologies are discussed. The key strategies employed include Pd(II)-catalyzed coupling and Wittig procedures.
Design of a LLC Resonant Converter for Powering a PEM Electrolyzer
2021
International audience; This paper proposes the design of a LLC resonant converter to supply a proton exchange membrane (PEM) electrolyzer. The PEM requires a low voltage with high current, a reduced output voltage ripple, and an overdamped dynamic behavior of the converter to avoid voltage overshoots. The designed converter allows satisfying the design constraints, minimizing switching and reverse recovery losses; the efficiency is influenced mainly by the output rectifier's conduction losses.
Measurements methodology for the reliability evaluation of intelligent power modules
2014
The paper describes a measurement methodology for the reliability evaluation of new intelligent power electronics modules (IPMs). In particular, the evaluation of the IPMs immunity to radio frequency conducted disturbances has been performed, at different operating thermal conditions, designing a suitable measurement set up in a shielded room. Moreover, the thermal performances of the devices have been analyzed, setting up a proper experimental test bench. The measurements procedures are detailed described. © 2014 IEEE.