Search results for "Quasistatic process"
showing 10 items of 25 documents
A differential equation approach to implicit sweeping processes
2019
International audience; In this paper, we study an implicit version of the sweeping process. Based on methods of convex analysis, we prove the equivalence of the implicit sweeping process with a differential equation, which enables us to show the existence and uniqueness of the solution to the implicit sweeping process in a very general framework. Moreover, this equivalence allows us to give a characterization of nonsmooth Lyapunov pairs and invariance for implicit sweeping processes. The results of the paper are illustrated with two applications to quasistatic evolution variational inequalities and electrical circuits.
Prediction of bone mechanical properties using QUS and pQCT: study of the human distal radius.
2007
Abstract The objective was to compare the prediction of bone mechanical properties provided by axial transmission to that provided by peripheral quantitative computed tomography (pQCT) at the distal radius. The distal radius is the location for Colles’ fractures, a common osteoporosis related trauma situation. Measurements of the radial speed of sound were performed using three axial transmission devices: a commercial device (Sunlight Omnisense, 1.25 MHz), a bi-directional axial transmission prototype (1 MHz), both measuring the velocity of the first arriving signal (FAS), and a low frequency (200 kHz) device, measuring the velocity of a slower wave. Co-localized pQCT measurements of bone m…
Quasi-static magnetoresistive sensor modeling for current-time conversion circuit applications
2011
In this paper we report a current-to-time converter (CTC) suitable for current sensor monitoring in low power applications. Based on a discrete resistence-to-frequency converter and a Giant MagnetoResistance (GMR) current sensor. Simulations have been done using a quasi-static electrical Verilog-A model for the GMR current sensor. A reduced set of parameters has been extracted to characterize the GMR sensor's behavior. The application has been analyzed making use of different sensors, whose device parameters were previously extracted. Finally, the accuracy of the models has been tested by comparing with experimental transient measurements.
Salt-fog spray aging of jute-basalt reinforced hybrid structures. Flexural and low velocity impact response
2017
Abstract In this work, a study on the aging resistance of jute and jute-basalt interply hybrid laminates exposed to salt-fog is presented with the aim to investigate the possibility to enhance the durability of natural fiber reinforced composites for marine application by a ply-substitution approach. In particular, jute and basalt/jute reinforced composite plates were manufactured by vacuum assisted resin infusion in two different staking sequences (i.e., intercalated and sandwich-like basalt-jute) and aged under salt fog conditions. The effects of the accelerated aging at increasing times on the mechanical response of laminates were assessed in both quasi static (three point bending) and d…
Monte Carlo Tests of Nucleation Concepts in the Lattice Gas Model
2013
The conventional theory of homogeneous and heterogeneous nucleation in a supersaturated vapor is tested by Monte Carlo simulations of the lattice gas (Ising) model with nearest-neighbor attractive interactions on the simple cubic lattice. The theory considers the nucleation process as a slow (quasi-static) cluster (droplet) growth over a free energy barrier $\Delta F^*$, constructed in terms of a balance of surface and bulk term of a "critical droplet" of radius $R^*$, implying that the rates of droplet growth and shrinking essentially balance each other for droplet radius $R=R^*$. For heterogeneous nucleation at surfaces, the barrier is reduced by a factor depending on the contact angle. U…
Molecule non-radiative coupling to a metallic nanosphere: an optical theorem treatment.
2009
The non-radiative coupling of a molecule to a metallic spherical particle is approximated by a sum involving particle quasistatic polarizabilities. We demonstrate that energy transfer from molecule to particle satisfies the optical theorem if size effects corrections are properly introduced into the quasistatic polarizabilities. We hope that this simplified model gives valuable information on the coupling mechanism between molecule and metallic nanos-tructures available for, e.g., surface enhanced spectroscopy signal analysis.
Self-similarity and scaling of thermal shock fractures
2013
The problem of crack pattern formation due to thermal shock loading at the surface of half-space is solved numerically using two-dimensional boundary element method. The results of numerical simulations with 100-200 random simultaneously growing and interacting cracks are used to obtain scaling relations for crack length and spacing. The numerical results predict that such process of pattern formation with quasi-static crack growth is not stable and at some point the excess energy leads to unstable propagation of one of the longest crack. The onset of instability has also been determined from numerical results.
Magnetic order and local field distribution in the hybrid magnets [FeCp*(2)][MnCr(ox)(3)] and [CoCp*(2)][FeFe(ox)(3)]: a muon spin relaxation study
2016
Zero-field muon spin relaxation (μ+SR) measurements on materials from the series [ZIIICp*2][M IIMIII(ox)3] show precession signals at several frequencies, characteristic of quasistatic magnetic fields at up to three distinct muon sites.
Static freezing transition at a finite temperature in a quasi-one-dimensional deuteron glass.
1996
The dipolar freezing process of a quasi-one-dimensional betaine deuteron glass was studied using linear and nonlinear dielectric spectroscopy. The linear response as measured for frequencies $5\mathrm{mHz}l\ensuremath{\nu}l200\mathrm{MHz}$ was analyzed using the recently invented $\ensuremath{\delta}$ plot, providing evidence for a static freezing transition near 30 K. Measurements of the ergodic to nonergodic transition as well as of the incipient divergence of the nonlinear susceptibility yield independent confirmation of this quasistatic freezing transition temperature. The critical exponent describing the nonlinear behavior is found to be $\ensuremath{\gamma}\phantom{\rule{0ex}{0ex}}=\p…
Fractional-Order Theory of Thermoelasticity. II: Quasi-Static Behavior of Bars
2018
This work aims to shed light on the thermally-anomalous coupled behavior of slightly deformable bodies, in which the strain is additively decomposed in an elastic contribution and in a thermal part. The macroscopic heat flux turns out to depend upon the time history of the corresponding temperature gradient, and this is the result of a multiscale rheological model developed in Part I of the present study, thereby resembling a long-tail memory behavior governed by a Caputo's fractional operator. The macroscopic constitutive equation between the heat flux and the time history of the temperature gradient does involve a power law kernel, resulting in the anomaly mentioned previously. The interp…