Influence of heating temperature on the aluminum used for electric cables

In this study, we present the effects of temperature rise on microstructural evolution of industrial Al wire. This material is used to manufacture electric cables. For the X-ray analysis of the line profile (LPA), we have chosen the so-called «breadth method» whose basic principle is to draw the Williamson-Hall plot. We have observed that the increase in temperature causes the increasing of coherent diffraction domains (crystallites) size, interplanar distance and cell parameter. There is an expansion of the unit cell. XRD patterns refinement were performed using the whole powder pattern modelling procedure implemented in PM2k software

Inverse estimation of the permeability of porous materials using experimental data via reflected waves at low frequencies

International audienceAn acoustic reflectivity method is proposed for measuring the permeability or flow resistivity of air-saturated porous materials. In this method, a simplified expression of the reflection coefficient is derived in the Darcy's regime (low frequency range), which does not depend on frequency and porosity. Numerical simulations show that the reflection coefficient of a porous material can be approximated by its simplified expression obtained from its Taylor development to the first order. This approximation is good especially for resistive materials (of low permeability) and for the lower frequencies. The permeability is reconstructed by solving the inverse problem using waves reflected by plastic foam samples, at different frequency bandwidths in the Darcy regime. The proposed method has the advantage of being simple compared to the conventional methods that use experimental reflected data, and is complementary to the transmissivity method which is more adapted to low resistive materials (high permeability)

Measuring static viscous permeability of porous absorbing materials

International audienceConventional acoustical methods for measuring the permeability or flow resistivity of a porous material require a priori estimation of the porosity. In this work, an acoustical method is presented in which a simplified expression (independent of both the frequency and porosity) for the transmitted waves at the Darcy’s regime (low frequency range) is derived, and used for the inverse determination of both the viscous static permeability (or flow resistivity) and the thickness of air-saturated porous materials. The inverse problem is solved based on the least-square numerical method using transmitted waves in time domain. Tests are performed using industrial plastic foams. Experimental and numerical validation results of this method are presented, which show theadvantage of measuring the viscous permeability and thickness of a porous slab, without the required prior knowledge of the porosity, but by simply using the transmitted waves

Coupled systems of fractional equations related to sound propagation: analysis and discussion

In this note we analyse the propagation of a small density perturbation in a one-dimensional compressible fluid by means of fractional calculus modelling, replacing thus the ordinary time derivative with the Caputo fractional derivative in the constitutive equations. By doing so, we embrace a vast phenomenology, including subdiffusive, superdiffusive and also memoryless processes like classical diffusions. From a mathematical point of view, we study systems of coupled fractional equations, leading to fractional diffusion equations or to equations with sequential fractional derivatives. In this framework we also propose a method to solve partial differential equations with sequential fractional derivatives by analysing the corresponding coupled system of equations

Linear Parsing Expression Grammars

PEGs were formalized by Ford in 2004, and have several pragmatic operators (such as ordered choice and unlimited lookahead) for better expressing modern programming language syntax. Since these operators are not explicitly defined in the classic formal language theory, it is significant and still challenging to argue PEGs' expressiveness in the context of formal language theory.Since PEGs are relatively new, there are several unsolved problems.One of the problems is revealing a subclass of PEGs that is equivalent to DFAs. This allows application of some techniques from the theory of regular grammar to PEGs. In this paper, we define Linear PEGs (LPEGs), a subclass of PEGs that is equivalent to DFAs. Surprisingly, LPEGs are formalized by only excluding some patterns of recursive nonterminal in PEGs, and include the full set of ordered choice, unlimited lookahead, and greedy repetition, which are characteristic of PEGs. Although the conversion judgement of parsing expressions into DFAs is undecidable in general, the formalism of LPEGs allows for a syntactical judgement of parsing expressions.Comment: Parsing expression grammars, Boolean finite automata, Packrat parsin

The Cost of Monitoring Alone

We compare the succinctness of two monitoring systems for properties of infinite traces, namely parallel and regular monitors. Although a parallel monitor can be turned into an equivalent regular monitor, the cost of this transformation is a double-exponential blowup in the syntactic size of the monitors, and a triple-exponential blowup when the goal is a deterministic monitor. We show that these bounds are tight and that they also hold for translations between corresponding fragments of Hennessy-Milner logic with recursion over infinite traces.Comment: 22 page

Sélection pour améliorer la tolérance aux stress abiotiques chez le blé dur (Triticum durum Desf.)

La présente étude s’est fixée pour objectif la sélection pour la tolérance aux stress abiotiques chez le blé dur (Triticum durum Desf.) à l’aide de tests physiologiques. 18 génotypes ont été étudiés sur deux sites au cours de deux années consécutives dans un dispositif en blocs complétement randomisés. Les résultats montrent que le rendement grain est lié au nombre de grains produit par unité de surface, à la biomasse aérienne mesurée à maturité, à l’indice de remplissage du grain et à l’efficacité d’utilisation de l’eau. Les valeurs de l’intégrité cellulaire, la turgescence foliaire et le rapport des concentrations chlorophylliennes a et b sont peu corrélées avec les moyennes des caractères phéno-morphologiques mesurés par site. L’intégrité cellulaire et la turgescence foliaire sont associées à la réduction du rendement grain sous stress. Les génotypes tolérants aux stress abiotiques minimisent la baisse du rendement en grains dans les environnements défavorables alors que les génotypes sensibles valorisent nettement mieux les sites et environnements favorables à l’expression du potentiel de production

Wave propagation in stereo-lithographical (STL) bone replicas at oblique incidence

Comparisons between predictions of a Biot-Allard model allowing for angle-dependent elasticity and angle-and-porosity dependent tortuosity and transmission data obtained at normal incidence on water-saturated replica bones are extended to oblique incidence. The model includes two parameters which are adjusted for best fit at normal incidence. Using the same parameter values, it is found that predictions of the variation of transmitted waveforms with angle through two types of bone replica are in reasonable agreement with data despite the fact that scattering is not included in the theory

Bioactive Lipids, Antibacterial, Hypoglycaemic, and Antioxidant Potentials of Immature and Mature Vicia faba L. Seeds Cultivated in Tunisia

Both the immature and mature Vicia faba L. seeds are used for human consumption. However, there is a lack of information on the phytochemical composition and the potent biological properties of the immature seeds. The aim of the present study was to establish the profile of bioactive lipids as well as the antibacterial, antioxidant, and α-amylase and α-glucosidase inhibitory capacities of the immature and mature Vicia faba L. seeds. The studied petroleum ether extracts contain different bioactive compounds such as β-sitosterol, lupeol, β-amyrin, α-tocopherol, and γ-tocopherol. The extracts of the immature seeds exhibited higher antioxidant and antibacterial activities than those of mature ones. All tested extracts exerted higher inhibition on α-glucosidase than α-amylase. The immature seeds appeared as promising sources of natural antioxidants, antibacterial compounds, and α-amylase and α-glucosidase inhibitors. Thus, the immature Vicia faba L. seeds have a great potential as functional foods providing health beneficial properties