191 research outputs found
A splitting method adapted to the simulation of mixed flows in pipes with a compressible two-layer model
No full textInternational audienceThe numerical resolution of the Compressible Two-Layer model proposed in [Demay & Hérard, CMAT 2017] is addressed in this work with the aim of simulating mixed flows and entrapped air pockets in pipes. This five-equation model provides a unified two-phase description of such flows which involve transitions between stratified regimes (air-water herein) and pressurized or dry regimes (pipe full of water or air). In particular, strong interactions between both phases and entrapped air pockets are accounted for. At the discrete level, the coexistence of slow gravity waves in the stratified regime with fast acoustic waves in the pressurized regime is difficult to approximate. Furthermore, the two-phase description requires to deal with vanishing phases in pressurized and dry regimes. In that context, a robust \bl{splitting method} combined with an implicit-explicit time discretization is derived. The overall strategy relies on the fast pressure relaxation in addition to a mimetic approach with the shallow water equations for the slow dynamics of the water phase. It results in a three-step scheme which ensures the positivity of heights and densities under a CFL condition based on the celerity of material and gravity waves. In that framework, an implicit \bl{relaxation-like} approach provides stabilization terms which are activated according to the flow regime. Numerical experiments are performed beginning with a Riemann problem for the convective part. The overall approach is then assessed considering relevant mixed flow configurations involving regime transitions, vanishing phases and entrapped air pockets
Trainee-ship in company Schneider Electric a.s.
No full textThe author briefly introduced the company and its Czech sales representative. She described her own course of practice, her position and the individual activities that she performed during practice. In the end, she commented on the benefits from the completed practice
Continous exposure to chrysotile asbestos can cause transformation of human mesothelial cells via HMGB1 and TNF-alpha signalling
No full textTheoretical and Experimental Study of Signal Processing Techniques for Measuring Hermetic Compressor Speed through Pressure and Current Signals
No full textMeasuring means extracting information from acquired signals. Either in the frequency or in the time, mathematical processing tools are applied to get information from measurement signals. It is usual, when processing measurement signals in the frequency domain, the application of Fourier analysis, mainly through Fast Fourier Transform (FFT) algorithms. Nevertheless, there are other digital signal processing tools that can overcome FFT performance in computation time or accuracy, and they can be very useful when extracting information from measurement signals. This paper presents some powerful mathematical tools and it shows how useful they can be, when measuring hermetic compressor speed through externally-measurable quantities
Deletion of vitamin D receptor leads to premature emphysema/COPD by increased matrix metalloproteinases and lymphoid aggregates formation
No full textDeficiency of vitamin D is associated with accelerated decline in lung function. Vitamin D is a ligand for nuclear hormone vitamin D receptor (VDR), and upon binding it modulates various cellular functions. The level of VDR is reduced in lungs of patients with chronic obstructive pulmonary disease (COPD) which led us to hypothesize that deficiency of VDR leads to significant alterations in lung phenotype that are characteristics of COPD/emphysema associated with increased inflammatory response. We found that VDR knock-out (VDR(-/-)) mice had increased influx of inflammatory cells, phospho-acetylation of nuclear factor-kappaB (NF-κB) associated with increased proinflammatory mediators, and up-regulation of matrix metalloproteinases (MMPs) MMP-2, MMP-9, and MMP-12 in the lung. This was associated with emphysema and decline in lung function associated with lymphoid aggregates formation compared to WT mice. These findings suggest that deficiency of VDR in mouse lung can lead to an early onset of emphysema/COPD because of chronic inflammation, immune dysregulation, and lung destruction
Autógrafos : revolución de España
No full textVolum de l'epistolari de Víctor Balaguer amb cartes dels següents corresponsals: Alcántara - Badules Oliván, Orencio - Baldrich, Gabriel - Barturdó - Bertrán, Eduardo - Bosch, J. - Botella - Botella, Federico - Buí - Buí, F. P. - Cirera? - Coca, Antonio - Cutchet, Luis? - Elías, José - Elías, Miguel - Ferratges, Antonio - Ferrer, Víctor - Genové, R. - Gil - J. P. - Jan Anto? - José de ? - Manuel - Mázaga, S. de - Méndez, Romualdo - Morlins, Manuel - Olózaga, Salustiano de - Ortiz - Pepe - Poses, B. - Prim - Prim, Juan - Puig Macià, Juan - Ratés, José de - Ruiz - Sagasta, Práxedes Mateo - Schoenbrunn, Demay de - Torres, Antonio de - Uriarte y Badía, Manuel de - Utrill
Application and comparison of three tomographic techniques for detection of decay in trees
No full textThis paper reports application of electric, ultrasonic, and georadar tomography for detection of decay in trees and their comparison with the traditional penetrometer. Their feasibility in arboriculture is also evaluated, critically considering some "open problems." The experiments were carried out in an urban environment on two plane (Platanus hybrida Brot.) trees. Both trees, after felling, showed extensive white rot in the central cylinder. The electric tomography revealed low resistivity zones roughly centered in the trunk. A comparison with the successively cut sections showed a fine correspondence to decayed areas and a strong correspondence between high moisture zones and low resistivity zones. Ultrasonic tomography demonstrated to be a very effective tool for the detection of internal decay, accurately locating the position of the anomalies and estimating their size, shape, and characteristic in terms of mechanical properties. With the georadar technique, the high contrast of electromagnetic impedance measured between the inner decayed section and the outside sound section allowed the detection of the interface between the sound and decayed section of the tree, using radar acquisition in reflection modality. The penetrometer profiles detected the low-resistance areas inside the two trunk
Continuous exposure to chrysotile asbestos can cause transformation of human mesothelial cells via HMGB1 and TNF-α signaling
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