Search results for "Thermal"
showing 10 items of 3576 documents
WS 2 /MoS 2 Heterostructures through Thermal Treatment of MoS 2 Layers Electrostatically Functionalized with W 3 S 4 Molecular Clusters
2020
The preparation of 2D stacked layers combining flakes of different nature gives rise to countless numbers of heterostructures where new band alignments, defined at the interfaces, control the electronic properties of the system. Among the large family of 2D/2D heterostructures, the one formed by the combination of the most common semiconducting transition metal dichalcogenides, WS2 /MoS2 , has awakened great interest owing to its photovoltaic and photoelectrochemical properties. Solution as well as dry physical methods have been developed to optimize the synthesis of these heterostructures. Here, a suspension of negatively charged MoS2 flakes is mixed with a methanolic solution of a cationi…
Thermo-Elasto-Hydrodynamic Analysis of a Crankshaft Journal Bearing
2006
This paper summarizes the essential parts of a numerical analysis activity in which the application of the Thermo-Elasto-Hydro-Dynamic (TEHD) lubrication theory to a crankshaft journal bearing is examined. The study is carried out through numerical computations performed by a commercial flexible-multibody code which simulates the lubricated contact between elastic bodies in large displacement motion. A multibody model has been created and its thermal behaviour has been validated by comparison with experimental temperatures. The validated model is used to perform two comparative analyses between the TEHD modelling and the Elasto-Hydro-Dynamic (EHD) modelling for max torque and max power cond…
Interpretation of epicardial mapping by means of computer simulations: Applications to calcium, lidocaine and to BRL 34915
1992
The aim of this work was to compare experimental investigations on effects of lidocaine, calcium and, BRL 34915 on reentries to simulated data obtained by use of a model of propagation based on the Huygens' construction method already described in previous works. Calcium and lidocaine effects are investigated on anisotropic conduction conditions. In both cases, reduction in conduction velocities are observed. In lidocaine case, a refractory area is located along the longitudinal axis. In agreement with experimental electrical mapping, the simulations show that the stabilization of reentrant excitation is mainly due to the existence of this refractory area around which the reentrant circuit …
The Role of Covalent Functionalization in the Thermal Stability and Decomposition of Hybrid Layered Hydroxides
2020
The room temperature synthesis of two Co-based hybrid layered hydroxides containing the same organic ligand (suberate [Sub]), one connected through purely electrostatic interactions (CoAl layered double hydroxide [LDH]), and the other covalently functionalized (α-CoII simonkolleite phase) has been carried out. The magnetic properties exhibit an acute difference in the magnetization temperatures (from ≈10 K for the CoAl-LDH to ≈55 K for the α-CoII). Moreover, the role of the covalent functionalization in the thermal stability and the decomposition has been investigated by a forefront characterization tool consisting of thermogravimetric analysis coupled with gas chromatography and mass spect…
Detecting crop irrigation status in orchard canopies with airborne and ASTER thermal imagery
2007
This work provides a description of the research conducted to assess if ASTER satellite data enable the detection of the water status in orchard tree crops. Summer and winter TERRA-ASTER images were acquired over a study area of Seville in southern Spain over a 6-year period. 1076 olive orchards were monitored in this area, obtaining field location, area, tree density, and irrigation status information. Surface temperature images were obtained using the TES method and 0.5 m resolution panchromatic ortho-rectified imagery collected over the entire area to obtain vegetation cover. A comparison study of the temperature difference between orchards under different irrigation schemes is presented…
A Temperature-Dependent X-Ray Absorption Characterization of Test Filters for the ATHENA Mission X-IFU Instrument
2018
In order to work properly, the X-ray Integral Field Unit of the ATHENA mission requires a set of thermal filters that block the infrared radiation, preventing it to reach the detector. Each filter will be mounted and thermally anchored onto a shield of the multistage cryostat and will be kept at the specific temperature of the stage. On the other hand, the filters partially absorb X-rays, and their transmittance has to be carefully characterized. The effect of temperature on the absorption edges of the elements that make up the filters has not been investigated yet. Here, we report the results of a preliminary run on the optical transmission data around the edges of C, N, and O at different…
Temperature effects on the performances of the ATHENA X-IFU thermal filters
2016
The X-Ray Integral Field Unit (X-IFU) detector on-board ATHENA is an array of TES micro-calorimeters that will operate at ~50 mK. In the current investigated design, five thermal filters (TF) will be mounted on the cryostat shields to attenuate IR radiative load and avoid energy resolution degradation due to photon shot noise. Each filter consists of a thin polyimide film (~50 nm thick) coated with aluminum (~30 nm thick). Since the TF operate at different temperatures in the range 0.05-300 K, it is relevant to study how temperature affects their mechanical/optical performances (e.g. near edge absorption fine structures of the atomic elements in the filter material). Such results are crucia…
Thermal modelling of the ATHENA X-IFU filters
2018
Copyright 2018 Society of Photo-Optical Instrumentation Engineers (SPIE). One print or electronic copy may be made for personal use only. Systematic reproduction and distribution, duplication of any material in this paper for a fee or for commercial purposes, or modification of the content of the paper are prohibited. The X-IFU instrument of the ATHENA mission requires a set of thermal filters to reduce the photon shot noise onto its cryogenic detector and to protect it from molecular contamination. A set of five filters, operating at different nominal temperatures corresponding to the cryostat shield temperatures, is currently baselined. The knowledge of the actual filter temperature profi…
Radio frequency shielding of thin aluminized plastic filters investigated for the ATHENA X-IFU detector
2018
Copyright 2018 Society of Photo-Optical Instrumentation Engineers (SPIE). One print or electronic copy may be made for personal use only. Systematic reproduction and distribution, duplication of any material in this paper for a fee or for commercial purposes, or modification of the content of the paper are prohibited. The X-ray Integral Field Unit (X-IFU) is one of the two detectors of the ATHENA astrophysics space mission approved by ESA in the Cosmic Vision 2015-2025 Science Programme. The X-IFU consists of a large array of transition edge sensors (TES) micro-calorimeters covering a field of view of 5' diameter, sensitive in the energy range 0.2-12 keV, and providing a spectral resolution…
Thermal Filters for the ATHENA X-IFU: Ongoing Activities Toward the Conceptual Design
2016
ATHENA is the L2 mission selected by ESA to pursue the science theme “Hot and Energetic Universe.” One of the two focal plane instruments is the X-ray Integral Field Unit, an array of TES microcalorimeters operated at T $$<$$ 100 mK. To allow the X-ray photons focused by the telescope to reach the detector, windows have to be opened on the cryostat thermal shields. X-ray transparent filters need to be mounted on these open windows to attenuate the IR radiation from warm surfaces, to attenuate RF electromagnetic interferences on TES sensors and SQUID electronics, and to protect the detector from contamination. This paper reviews the ongoing activities driving the design of the X-IFU thermal …