Search results for "Electron"
showing 10 items of 24810 documents
Modelling Complex Volume Shape Using Ellipsoid: Application to Pore Space Representation
2017
Natural shapes have complex volume forms that are usually difficult to model using simple analytical equations. The complexity of the representation is due to the heterogeneity of the physical environment and the variety of phenomena involved. In this study we consider the representation of the porous media. Thanks to the technological advances in Computed Topography scanners, the acquisition of images of complex shapes becomes possible. However, and unfortunately, the image data is not directly usable for simulation purposes. In this paper, we investigate the modeling of such shapes using a piece wise approximation of image data by ellipsoids. We propose to use a split-merge strategy and a…
Evidence of active fluid seepage (AFS) in the southern region of the central Mediterranean Sea
2018
Abstract Active fluid seepage (AFS) at the seafloor is a global phenomenon associated with seafloor morphologies in different geodynamic contexts. Advanced geophysical techniques have allowed geoscientists to characterise pockmarks, mounds and flares associated with AFS. We present a range of new marine geological data acquired in the southern region of the central Mediterranean Sea (northern Sicily continental margin, northwestern Sicily Channel and offshore of the Maltese Islands), which allow us to identify AFSs. AFSs are spatially distributed as clusters, aligned or isolated at different depths, ranging from few decametres offshore of the Maltese Islands; up to 400 m offshore of norther…
Impulsive coronal heating from large-scale magnetic rearrangements: from IRIS to SDO/AIA
2019
The Interface Region Imaging Spectrograph (IRIS) has observed bright spots at the transition region footpoints associated with heating in the overlying loops, as observed by coronal imagers. Some of these brightenings show significant blueshifts in the Si iv line at 1402.77 A (logT[K] = 4.9). Such blueshifts cannot be reproduced by coronal loop models assuming heating by thermal conduction only, but are consistent with electron beam heating, highlighting for the first time the possible importance of non-thermal electrons in the heating of non-flaring active regions. Here we report on the coronal counterparts of these brightenings observed in the hot channels of the Atmospheric Imaging Assem…
Towards LST split-window algorithm FPGA implementation for CubeSats on-board computations purposes
2019
ABSTRACTNano, pico, and the so-called CubeSat satellites are taking place due to the emergent improvements in both high-performance nano and pico electronics and computational technologies. More th...
Decrespignyite-(Y), a new copper yttrium rare earth carbonate chloride hydrate from Paratoo, South Australia
2002
AbstractDecrespignyite-(Y) is a new copper yttrium rare earth carbonate chloride hydrate from the Paratoo copper mine, near Yunta, Olary district, South Australia. Decrespignyite-(Y) occurs as blue crusts, coatings and fillings in thin fissures on the slatey country rock. Individual pseudohexagonal platelets are typically 10–50 µm in maximum dimension and are often curved. Associated minerals include caysichite-(Y), donnayite-(Y), malachite and kamphaugite-(Y). Electron microprobe and CHN analyses gave: Y2O3 42.2; La2O3 0.1; Pr2O3 0.1; Nd2O3 1.3; Sm2O3 1.0; Gd2O3 4; Tb2O3 0.4; Dy2O3 3.7; Ho2O3 2.6; Er2O3 2.5; CaO 0.5; CuO 10.9; Cl 3.0; CO2 19.8; H2O 10.8, yielding an empirical formula of (Y…
Models and data analysis tools for the Solar Orbiter mission
2020
All authors: Rouillard, A. P.; Pinto, R. F.; Vourlidas, A.; De Groof, A.; Thompson, W. T.; Bemporad, A.; Dolei, S.; Indurain, M.; Buchlin, E.; Sasso, C.; Spadaro, D.; Dalmasse, K.; Hirzberger, J.; Zouganelis, I.; Strugarek, A.; Brun, A. S.; Alexandre, M.; Berghmans, D.; Raouafi, N. E.; Wiegelmann, T.; Pagano, P.; Arge, C. N.; Nieves-Chinchilla, T.; Lavarra, M.; Poirier, N.; Amari, T.; Aran, A.; Andretta, V.; Antonucci, E.; Anastasiadis, A.; Auchère, F.; Bellot Rubio, L.; Nicula, B.; Bonnin, X.; Bouchemit, M.; Budnik, E.; Caminade, S.; Cecconi, B.; Carlyle, J.; Cernuda, I.; Davila, J. M.; Etesi, L.; Espinosa Lara, F.; Fedorov, A.; Fineschi, S.; Fludra, A.; Génot, V.; Georgoulis, M. K.; Gilbe…
Evaluation of different methods to retrieve the hemispherical downwelling irradiance in the thermal infrared region for field measurements
2013
International audience; The thermal infrared hemispherical downwelling irradiance (HDI) emitted by the atmosphere and surrounding elements contributes through reflection to the signal measured over an observed surface by remote sensing. This irradiance must be estimated in order to obtain accurate values of land-surface temperature (LST). There are some fast methods to measure the HDI with a single measurement pointing to the sky at a specified viewing direction, but these methods require completely cloud-free or cloudy skies, and they do not account for the radiative contribution of surrounding elements. Another method is the use of a diffuse reflectance panel (usually, a rough gold-coated…
A Geometry-Based Underwater Acoustic Channel Model Allowing for Sloped Ocean Bottom Conditions
2017
This paper proposes a new geometry-based channel model for shallow-water ocean environments, in which the ocean bottom can slope gently down/up. The need for developing such an underwater acoustic (UWA) channel model is driven by the fact that the standard assumption of a flat ocean bottom does not hold in many realistic scenarios. Starting from a geometrical model, we develop a stochastic channel model for wideband single-input single-output vehicle-to-vehicle UWA channels using the ray theory assuming smooth ocean surface and bottom. We investigate the effect of the ocean-bottom slope angle on the distribution of the channel envelope, instantaneous channel capacity, temporal autocorrelati…
A Nonisovelocity Geometry-Based Underwater Acoustic Channel Model
2018
This paper proposes a new geometry-based shallow underwater acoustic (UWA) channel model allowing for nonisovelocity ocean conditions. The fact that the isovelocity assumption does not hold in many real-world scenarios motivates the need for developing channel models for nonisovelocity UWA propagation environments. Starting from a geometrical model, we develop a stochastic channel model for a single-input single-output (SISO) vehicle-to-vehicle UWA channel assuming that the ocean surface and bottom are rough and that the speed of sound varies with depth. The effect of the nonisovelocity condition has been assessed regarding its influence on the temporal autocorrelation function, the frequen…
Effects of cooking on mollusk shell structure and chemistry: Implications for archeology and paleoenvironmental reconstruction
2016
Mollusk shells excavated from archeological sites have been used to reconstruct paleoenvironment, human foraging, and migratory patterns. To retrieve information on past environment or human behavior, chemical signatures such as oxygen stable isotopes (δ18Oshell) are analyzed. Shell archeological remains usually represent food waste. Thermal treatments such as boiling and roasting may influence shell structure and biochemical composition. However, little is known about the relationship between changes at macro-, microstructural and chemical levels. This work is a calibration study on modern Phorcus (Osilinus) turbinatus shells. A simulation of two different cooking methods (boiling and roas…