Search results for "plastic"
showing 10 items of 7296 documents
Hacia una propuesta metodológica para el estudio de la atenuación fónica en Es.Var.Atenuación
2017
espanolEl proyecto Es.Var.Atenuacion se interesa por el estudio de la atenuacion pragmatica a nivel linguistico, estructural, enunciativo y situacional, en corpus discursivos del espanol, a fin de reconocer las posibles estrategias atenuantes de un acto comunicativo. Para llevar a cabo el analisis se parte de una ficha de trabajo (Briz y Albelda, 2013. Una propuesta teorica y metodologica para el analisis de la atenuacion linguistica en espanol y portugues. La base de un proyecto comun (ES. POR.ATENUACION). Onomazein, 28, pp. 288–319; Albelda, Briz, Cestero, Kotwica y Villalba, 2014. Ficha metodologica para el analisis pragmatico de la atenuacion en corpus discursivos del espanol. (ES.POR.A…
Economic Support during the COVID Crisis. Quantitative Easing and Lending Support Schemes in the UK
2021
Abstract We investigate how UK bank business lending responded to the simultaneous use of quantitative easing, leverage ratio capital requirements, and government COVID lending support schemes. We find no evidence that the Brexit wave increased lending to nonfinancial businesses, compared to the previous waves, except for QE-banks subject to the UK leverage ratio, suggesting that the ratio incentivised QE-banks to lend to businesses. The government schemes helped expand lending especially to SMEs post the COVID wave, indicating that complementing QE with other credit easing programmes can reinforce its impact on lending to the real economy. During COVID-stress, changes to the UK leverage ra…
Plastic yielding of glass in high-pressure torsion apparatus
2018
International audience; Hardness measurements performed at room temperature have demonstrated that glass can flow under elevated pressure, whereas the effect of high pressure on glass rheology remains poorly quantified. Here, we applied a high-pressure torsion (HPT) apparatus to deform SCHOTT SF6 â glass and attempted to quantify the effect of pressure and temperature on the shear deformation of glass subjected to pressures from 0.3 GPa to 7 GPa and temperatures from 25 ℃ to 496 ℃. Results show that the plastic yield deformation was occurring during the HPT experiments on the SF6 glass at elevated temperature from 350 ℃ to 496 ℃. The yield stress of SF6 glass decreases with increasing tempe…
Dielectric response of BaTiO3 electronic states under AC fields via microsecond time-resolved X-ray absorption spectroscopy
2021
Abstract For the first time, the dielectric response of a BaTiO 3 thin film under an AC electric field is investigated using microsecond time-resolved X-ray absorption spectroscopy at the Ti K-edge in order to clarify correlated contributions of each constituent atom on the electronic states. Intensities of the pre-edge e g peak and shoulder structure just below the main edge increase with an increase in the amplitude of the applied electric field, whereas that of the main peak decreases in an opposite manner. Based on the multiple scattering theory, the increase and decrease of the e g and main peaks are simulated for different Ti off-center displacements. Our results indicate that these s…
Correlative study of structural and optical properties of ZnSe under severe plastic deformation
2019
The effect of plastic deformation on the optical and structural properties of ZnSe crystals has been investigated. The optical properties have been monitored by cathodoluminescence measurements as a function of the deformation degree. Remarkable differences in the defect-related emissions from the most severely deformed areas have been encountered. Deformation of the crystal lattice of ZnSe, associated with slip phenomena, has been studied by means of Electron Backscattered Diffraction and micro-Raman spectroscopy. The relation between the deformation and the optical properties of the ZnSe crystals has been described.
Modeling self-sustaining waves of exothermic dissolution in nanometric Ni-Al multilayers
2016
Abstract The self-sustained propagating reaction occurring in nanometric metallic multilayers was studied by means of molecular dynamics (MD) and numerical modeling. We focused on the phenomenon of the exothermic dissolution of one metallic reactant into the less refractory one, such as Ni into liquid Al. The exothermic character is directly related to a negative enthalpy of mixing. An analytical model based on the diffusion-limited dissolution [1] coupled with heat transfer was derived to account for the main aspects of the process. Together, several microscopic simulations were carried out. The first series were set up to obtain all the parameters governing the process, including the heat…
Analysis of nonlinear time-dependent properties of carbon fiber reinforced plastic under off-axis loading
2021
Abstract Polymeric composites are rheonomic materials and their deformation can be described using the hereditary elasticity relations which allow for describing the mechanical behavior under time-variable loading with consideration of the influence of temperature and other operational factors. A system of hereditary-type constitutive relations is proposed for off-axis specimens of a unidirectional carbon fiber-reinforced plastic subjected to loading at different strain rates. Using the algebra of resolvent operators and inverted transformation, the constitutive equations allowing of description of anisotropy of rheological properties and, in particular, sensitivity to strain rates are deri…
Experimental and numerical investigation on a new FSW based metal to composite joining technique
2018
Abstract In the last decades, different techniques were proposed to join aluminum sheets with composites materials. Each of them has advantages and weak points over the others and new techniques and patents are continuously developed to overcome these difficulties. In this paper an experimental and numerical investigation on a new Friction Stir Welding based approach to mechanically join AA6082-T6 to self-reinforced polypropylene is presented. The aluminum sheet is pre-holed along both the sides of the weld line and a pinless tool generates the heat and pressure needed to prompt back-extrusion of the composite. New experimental fixtures and hole designs were investigated in order to enhance…
Long-term moisture absorption and durability of FRP pultruded rebars
2021
Abstract Up to 15-years long moisture diffusion into carbon, glass, and aramid fiber reinforced plastic (FRP) rebars is studied. To eliminate uncertainties in identification of the radial and axial diffusivities, a successive methodology for determination of the diffusion coefficients is proposed. The concept of apparent diffusivity taking into account anisotropy and edge effects is extended to cylindrical samples. The ratio of the axial and radial diffusivities is the lowest for carbon (3) and the highest for glass (81) FRP rebars. Durability performance of the rebars is estimated by monitoring their interlaminar shear strength (ILSS). Long-term exposure of FRP rebars in a humid environmen…
Optimization of physicochemical and optical properties of nanocrystalline TiO 2 deposited on porous silicon by metal-organic chemical vapor depositio…
2020
International audience; Titanium dioxide (TiO2) is very employed in solar cells due to its interesting physicochemical and optical properties allowing high device performances. Considering the extension of applications in nanotechnologies, nanocrystalline TiO2 is very promising for nanoscale components. In this work, nanocrystalline TiO2 thin films were successfully deposited on porous silicon (PSi) by metal organic chemical vapor deposition (MOCVD) technique at temperature of 550°C for different periods of times: 5, 10 and 15 min. The objective was to optimize the physicochemical and optical properties of the TiO2/PSi films dedicated for photovoltaic application. The structural, morphologi…