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This study focuses on the development of a theoretical and experimental acoustic method and setup for studying the micropolar behavior of materials. Two types of low density closed-cell foams made from polystyrene (expanded and extruded) materials that were previously reported as materials exhibiting the non-classical elastodynamic behavior were investigated in order to reveal the particular comportment using acoustic waves. Two different types of transducers were employed to provide a large frequency band to study the influence of the Cosserat parameters. The frequency band from 1–40 kHz was covered using a tweeter loudspeaker whereas that from 30–120 kHz, by an air coupled ultrasonic transducer. The materials’ micropolar elastic behavior were revealed through the comparison between the theoretical and experimental transmission coefficients. At the cut-off frequency where the theoretical phase velocity of the transverse acoustic mode was established to be infinite, the acoustic wave transmission by the panels was found to be very small. This makes the Cosserat materials appealing to harmonic noise reduction.

International audience; In this article, a modeling extension for the description of wave propagation in porous media at low-mid frequencies is introduced. To better characterize the viscous and inertial interactions between the fluid and the structure in this regime, two additional terms described by two parameters α1 and α2 are taken into account in the representation of the dynamic tortuosity in a Laurent-series on frequency. The model limitations are discussed. A sensitivity analysis is performed, showing that the influence of α1 and α2 on the acoustic response of porous media is significant. A general Bayesian inference is then conducted to infer, simultaneously, the posterior probability densities of the model parameters. The proposed method is based on the measurement of waves transmitted by a slab of rigid porous material, using a temporal model for the direct and inverse transmission problem. Bayesian inference results obtained on three different porous materials are presented, which suggests that the two additional parameters are accessible and help reduce systematic errors in the identification of other parameters: porosity, static viscous permeability, static viscous tortuosity, static thermal permeability, and static thermal tortuosity.

International audience; The purpose of this paper is to present a method for the ultrasonic characterization of air-saturated porous media, by solving the inverse problem using only the reflected waves from the first interface to infer the porosity, the tortuosity and the viscous and thermal characteristic lengths. The solution of the inverse problem relies on the use of different reflected pressure signals obtained under multiple obliquely incident waves, in the time domain. In this paper, the authors propose to solve the inverse problem numerically with a first level Bayesian inference method, summarizing the knowledge on the inferred parameters in the form of posterior probability densities, exploring these densities using a Markov-Chain Monte-Carlo approach. Despite their low sensitivity to the reflection coefficient, it is still possible to extract the knowledge of the viscous and thermal characteristic lengths, allowing the simultaneous determination of all the physical parameters involved in the expression of the reflection operator. To further constrain the problem and guide the inference, the knowledge of a particular incident angle is used at one's advantage in order to more precisely define the thermal length, by effectively yielding a statistical relationship between tortuosity and characteristic lengths ratio.

Structural evolution of odd-even and odd-odd Mn isotopes from the valley of stability up to neutron dripline is studied in the framework of the self-consistent mean-field theory of Hartree–Fock–Bogoliubov. Three Skyrme effective interactions, namely, SLy4, SLy5 and SLy5T, are employed to investigate the tensor force effect on the ground-state properties. It is shown that the calculated quantities with the SLy4 interaction correctly reproduce the available experimental data and agree well with finite range droplet model and relativistic mean-field predictions. An inconsistency has been observed between the curves of the separation energies and that of the charge radius around N = 40. It is explained by the flatness of the potential energy curves in this region. The SLy5 and SLy5T results point to the necessity to refit all the Skyrme parameters after including the tensor terms.

International audience; This paper provides a time domain model for the propagation of transient ultrasonic waves in a self-similar porous material having a rigid frame. This model is based on the formalism of Stillinger-Palmer-Stavrinou, which consists in modeling the fractal material as a porous medium with a non-integer dimensional space. This paper is devoted to the time-domain analytical calculus of the reection and transmission operators that are expressed in terms of Mittag-Leer functions. A sensitivity numerical study using ultrasonic reected and transmitted waves is performed, highlighting the eect of of the material's physical parameters (fractal dimension, tortuosity, viscous characteristic length and porosity) on the waveforms.

Acoustic propagation in a self-similar porous medium having a rigid frame is studied. A fractional propagation equation in a porous material of non-integer dimension is established using the variational method (Stillinger–Palmer–Stavrinou formalism). The wave equation is solved analytically in the time domain using the Laplace transform method. The analytical solution of the propagation equation shows the existence of a supersonic wave whose front wave velocity depends on the non-integer dimension and the tortuosity of the self-similar porous material. Numerical simulations of the amplitude of the ultrasonic wave inside the material show the sensitivity of the main important parameters describing the propagation (non-integer dimension, tortuosity, viscous and thermal characteristic lengths). The non-integer dimension seems to be the only parameter which acts on both the amplitude and the velocity of the acoustic wave.

International audience; This study concerns the acoustic wave diffusion in fractional dimensional rigid porous media in the low frequency domain. An equivalent fluid model with a non-integer dimensional space is developed using the Stillinger-Palmer-Stavrinou formalism. A generalized lossy diffusive equation is derived and solved analytically in the time domain. The coefficients of the diffusion equation are not constant and depend on the fractional dimension, static permeability and porosity of the porous material. The dynamic response of the material is obtained using the Laplace transform method. Numerical simulations of a diffusive wave in porous material with a non-integer dimensional space are given, showing the sensitivity of the waveform to the fractional dimension. It is found that the attenuation of the acoustic wave is more important for the the highest value of the fractional dimension d. This result is especially true for resistive porous materials (low permeability value) and for large thicknesses.

International audience; In this paper, a modeling extension for the description of wave propagation in rigid porous media at high frequencies is used. To better characterize the visco-inertial and thermal interactions between the fluid and the structure in this regime, two additional characteristic viscous and thermal surfaces R and R0 are taken into account, as initially introduced in Kergomard, Lafarge, and Gilbert [Acta Acust. Acust. 99(4), 557–571 (2013)]. This extends the modeling order of the dynamic tortuosity and compressibility. A sensitivity analysis is performed on the additional parameters, showing that only the viscous surface R has an influence on transmitted waves in the high frequency regime, for materials having a low viscous characteristic length. A general Bayesian inference is then conducted to infer simultaneously the posterior probability densities of the parameters associated with the visco-inertial effects, i.e., the porosity, tortuosity, the viscous characteristic length, and the viscous characteristic surface. The proposed method is based on the measurement of waves transmitted by a slab of rigid porous material in the time domain. Bayesian inference results obtained on three different porous materials are presented.

International audience; Transient ultrasonic propagation in human bone tissue is considered according to Biot's theory. The bone is modeled as a porous medium with an elastic structure. The viscous uid/structure interactions are described by fractional calculus in the time domain. The slow and fast compressional waves, as well as the rotational shear wave predicted by Biot's theory obey fractional propagation equations. The fractional equation system is solved analytically in the time domain, thus obtaining the expressions of the reection and transmission scattering operators. Inverse identication of the intrinsic microstructure of the pores and of the mechanical properties of the bone is performed in the time domain (waveforms) and frequency domain (attenuation and phase velocities), by adopting a statistical Bayesian inference technique using ultrasonic transmitted and reected signals, which allows to nd the identied parameters and their associated uncertainty.

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Alpha decay properties of superheavy nuclei are investigated within the Unified Fission Model based on a Modified Wood-Saxon potential. In a first step, the predictive power of the model was confirmed in the region of heavy and super-heavy nuclei using different mass tables. The present model was subsequently applied in Z = 120–130 region. The computed alpha decay half-lives are compared, on the one hand, with those obtained in the framework of the Coulomb and proximity potential model and, on the other hand, with the spontaneous fission half-lives.Alpha decay properties of superheavy nuclei are investigated within the Unified Fission Model based on a Modified Wood-Saxon potential. In a first step, the predictive power of the model was confirmed in the region of heavy and super-heavy nuclei using different mass tables. The present model was subsequently applied in Z = 120–130 region. The computed alpha decay half-lives are compared, on the one hand, with those obtained in the framework of the Coulomb and proximity potential model and, on the other hand, with the spontaneous fission half-lives.

International audience; This chapter provides different models for the acoustic wave propagation in porous materials having a rigid and an elastic frames. The direct problem of reflection and transmission of acoustic waves by a slab of porous material is studied. The inverse problem is solved using experimental reflected and transmitted signals. Both high-and low-frequency domains are studied. Different acoustic methods are proposed for measuring physical parameters describing the acoustic propagation as porosity, tortuosity, viscous and thermal characteristic length, and flow resistivity. Some advantages and perspectives of this method are discussed.

Exotic decay of axially symmetric even-even and odd-even Nd isotopes is investigated within the Hartree-Fock-Bogoliubov theory. Calculations have been performed to determine the released energy for several clusters. The obtained energy is then used to calculate the cluster decay half-lives within the Unified Fission Model based on a modified Woods-Saxon potential. The results are compared with the available experimental data and those computed in the framework of the relativistic mean-field model.

In medium-mass nuclei close to the N=Z line, the neutron-proton (np) pairing correlations play an important role. They are generally studied within the BCS approach, but the main shortcoming of the latter is the particle-number fluctuation. A projection is thus necessary. Furthermore, the charge-radius is one of the fundamental properties of atomic nuclei. Its study may provide useful information about their size and shape. The isovector np pairing effects as well as those of the particle-number projection on the proton system radii of even-even nuclei such as N close to Z have been recently studied. The aim of the present contribution is to study these effects on the charge-radii of odd-mass nuclei in the same region. As a first step, an expression of the projected quadratic charge radius is established using the Sharp-BCS (SBCS) method. It is shown that it generalizes the one obtained when only the like-particles pairing is considered. As a second step, the charge-radii of some odd-mass nuclei are calcu...

An expression of the number-projected nuclear moment of inertia is established in the neutron-proton (np) isovector pairing case using the Sharp-BCS projection method. It is then exempt from the particle-number fluctuations which are inherent to the BCS approach. It is shown that it generalizes the one obtained when only the like-particles pairing is considered. The formalism is applied to the schematic Richardson model. The obtained results are compared to the ones obtained before the projection, as well as to the ones obtained in the like-particles pairing case. It is shown that the np pairing effect is non-negligible either before or after the projection. As for the projection effect, it appears to be more important in the np pairing case than in the like-particles pairing one.

International audience; In this paper, an enhanced method is proposed for measuring porosity, tortuosity, viscous and thermal characteristic length of porous materials having a rigid frame via reflected ultrasonic waves at oblique incidence using the equivalent fluid model. The advantage of the proposed method is that the four parameters are determined simultaneously just using reflected experimental waves for a porous material saturated by air. The inverse problem is solved based on the least-square numerical method using experimental reflected waves in time domain. Tests are performed using industrial plastic foams. Experimental and numerical validation results of this method are presented.

International audience; Measurement of tortuosity and viscous characteristic length of Double-layered porous absorbing materials with rigid-frames via transmitted ultrasonic-wave-Manuscript Draft-Manuscript Number: Full Title: Measurement of tortuosity and viscous characteristic length of Double-layered porous absorbing materials with rigid-frames via transmitted ultrasonic-wave Abstract: In this work, an indirect method is proposed for measuring simultaneously acoustic parameters describing the ultrasonic propagation in double-layered porous medium. The porous media consist of two slabs of homogeneous isotropic porous materials with a rigid frame. Each porous slab is described by equivalent fluid model, in which the acoustic wave propagates only in the fluid saturating the material. The inverse problem is solved numerically using experimental transmitted waves in time domain. Four parameters are inverted: tortuosity and viscous characteristic lengths of the two layers. Tests are performed using industrial plastic foams. Experimental and numerical validation results of this method are presented.

International audience; In this paper, reflection waves by the first interface of porous medium having rigid frame is considered. The method presented in this work is based on a temporal model of the direct problem in which a simplified expression of the reflection coefficient at the Darcy's regime (low frequency range) is established using equivalent fluid model, this expression depends only on the porosity and the viscous permeability (or the flow resistivity) of the medium. The simulated reflected wave is obtained in time domain by convolution between the reflected operator and the incident field. Experimental results are given for samples of air-saturated plastic foams and compared with theoretical predictions.

International audience; An acoustic method based on sound transmission is proposed for deducing the static thermal permeability and the inertial factor of porous materials having a rigid frame at low frequencies. The static thermal permeability of porous material is a geometrical parameter equal to the inverse trapping constant of the solid frame [Lafarge et al., J. Acoust. Soc. Am. 102, 1995 (1997)] and is an important characteristic of the porous material. The inertial factor [Norris., J. Wave Mat. Interact. 1, 22 365 (1986)] describes the fluid structure interactions in the low frequency range (1-3 kHz). The proposed method is based on a temporal model of the direct and inverse scattering problems for the propagation of transient audible frequency waves in a homogeneous isotropic slab of porous material having a rigid frame. The static thermal permeability and the inertial factor are determined from the solution of the inverse problem. The minimization between experiment and theory is made in the time domain. Tests are performed using industrial plastic foams. Experimental and theoretical data are in good agreement. Furthermore, the prospects are discussed. This method has the advantage of being simple, rapid, and efficient.

Expressions of temperature-dependent perpendicular (ℑ⊥) and parallel (ℑ‖) moments of inertia, including isovector pairing effects, have been established using the cranking method. They are derived from recently proposed temperature-dependent gap equations. The obtained expressions generalize the conventional finite-temperature BCS (FTBCS) ones. Numerical calculations have been carried out within the framework of the schematic Richardson model as well as for nuclei such as N = Z, using the single-particle energies and eigenstates of a deformed Woods–Saxon mean-field. ℑ⊥ and ℑ‖ have been studied as a function of the temperature. It has been shown that the isovector pairing effect on both the perpendicular and parallel moments of inertia is non-negligible at finite temperature. These correlations must thus be taking into account in studies of warm rotating nuclei in the N ≃ Z region.

The influence of the isovector neutron–proton (np) pairing effect on nuclear statistical quantities is studied in N ≈ Z even–even systems. Expressions of the energy, the entropy, and the heat capacity are established using a recently proposed temperature-dependent isovector pairing gap equations. They generalize the conventional finite temperature BCS (FTBCS) ones. The model is first numerically tested using the schematic one-level model. As a second step, realistic cases are considered using the single-particle energies of a deformed Woods–Saxon mean-field. It is shown that: (i) the gap parameter Δnp(T) behaves like Δtt(T), t = n, p, in the conventional FTBCS model and the critical temperature value Tcnp is such as Tcnpcpcn; (ii) the behavior of Δtt(T), t = n, p in the present model is different from that of the FTBCS one. This fact leads to a systematic discrepancy between the predictions of both models in the Tcnpcn region for all studied statistical quantities; and (iii) in the 0≤T≤Tcnp region, the np pairing effect on the energy is a lowering of about 1%, on average, for all considered nuclei. Dealing with the entropy and the heat capacity, the np pairing effect appears only if the Tcnp value is sufficiently important.

Using the Hartree–Fock–Bogoliubov mean-field theory, the ground-state structural and decay properties of Nd isotopes are investigated from the proton-rich side up to the neutron drip-line. Quantities such as binding energies per nucleon, one and two-neutron separation energies, rms charge radii, and quadrupole deformation parameters have been calculated. Compared with the relativistic mean-field results, the present calculations are in better agreement with the available experimental data. The results show clearly the signature of a shape transition at [Formula: see text] and an abrupt increase in the deformation near the neutron drip-line. Further, the possible decay modes like alpha, cluster and [Formula: see text]-decay are analyzed in a unified fission model and phenomenological formulas. Overall, a good agreement is achieved between the calculated and experimental [Formula: see text]-values and half-lives wherever available. The most likely decay modes are thus identified throughout the isotopic chain.

Particle-number fluctuations effects on the beta transition probabilities are studied in the neutron–proton pairing framework. The Hamiltonian of the system has been considered in its most general form and has been diagonalized by means of the linearization method. However, since the generalized Bogoliubov–Valatin transformation obtained in this way leads to a quasi-particle Hamiltonian which is still nondiagonal, a rediagonalization has been performed. The corresponding wave functions have been projected on both the good neutron and proton numbers using a recently proposed method. Expressions of the beta transition probabilities which strictly conserve the particle-number have then been established. As a first step, the model has been numerically tested within the framework of the schematic one-level model. As a second step, nuclei such as N = Z has been studied using the single-particle energies and eigenstates of the Woods–Saxon deformed mean field. It has thus been shown the necessity of: (i) including the isovector pairing correlations, (ii) performing a rediagonalization of the Hamiltonian, (iii) performing a particle-number projection, (iv) carefully choice the pairing-strength values, when calculating the transition probabilities.

Gap equations at finite temperature are established in the isovector plus isoscalar pairing case [Formula: see text] using a path integral approach. Expressions of the various statistical quantities, i.e., the energy, the entropy and the heat capacity are then deduced. It is shown that they do generalize the ones obtained in the pure isovector ([Formula: see text]) pairing case, as well as those obtained within the conventional finite temperature Bardeen–Cooper–Schrieffer (FTBCS) theory in the pairing between like-particles case. A numerical study is then performed using the schematic one-level model. It is shown that the isoscalar n–p gap parameter [Formula: see text] behaves as a function of the temperature, like its homologues [Formula: see text] and [Formula: see text] in the conventional FTBCS approach. As for the three other gap parameters, i.e., [Formula: see text], [Formula: see text] and [Formula: see text], their behaviors are clearly modified when the isoscalar pairing is taken into account. In particular, one observes a shift of the values of the critical temperatures. Dealing with the statistical quantities, the inclusion of the isoscalar pairing, in addition to the isovector one, leads to a lowering of the energy as well as a change of the shapes of the curves of the energy, the entropy and the heat capacity as a function of the temperature.

Isovector neutron-proton (np) pairing and particle-number fluctuation effects on the spectroscopic factors (SF) corresponding to one-pair like-particle transfer reactions in proton-rich even-even nuclei are studied. With this aim, expressions of the SF corresponding to two-neutron stripping and two-proton pick-up reactions, which take into account the isovector np pairing effect, are established within the generalized BCS approach, using a schematic definition proposed by Chasman. Expressions of the same SF which strictly conserve the particle number are also established within the Sharp-BCS (SBCS) discrete projection method. In both cases, it is shown that these expressions generalize those obtained when only the pairing between like particles is considered. First, the formalism is tested within the Richardson schematic model. Second, it is applied to study even-even proton-rich nuclei using the single-particle energies of a Woods-Saxon mean-field. In both cases, it is shown that the np pairing effect and the particle-number projection effect on the SF values are important, particularly in N=Z nuclei, and must then be taken into account.

For the past couple of years, Plug-in Hybrid Electric Vehicles (PHEVs) demonstrated their ability to significantly reduce petroleum consumptions. However, more than any other vehicle powertrain, their benefits are dependent on the driving cycles from both an aggressiveness and distance point of view. In this paper, two powertrain configurations will be defined. A power split configuration will be used for low battery energy and a series configuration for high battery energy. For each vehicle we will evaluate several control strategies, including electrical dominant and blended, on real world drive cycles. A conventional vehicle will be defined to use as a baseline. The trade-off between fuel displacement and cost will be evaluated for each option.

The variation of the two-neutron separation energy (S2N), as a function of the neutron number N, is studied using a microscopic model that includes the pairing effects rigorously within the Fixed-Sharp-BCS method. The model was first tested on "ordinary" nuclei and allowed one to suitably reproduce the experimental data and to confirm the results of previous studies. The model was then applied to the even–even neutron-rich isotopes in the rare-earth region and showed, on the one hand, a relatively important variation of S2N, when N = 100, that could lead to the assumption of the existence of a new magic number in this region, and on the other hand, a weak variation of S2N when N > 100. These findings corroborate the previously obtained results for the charge mean square radius and the quadrupole and hexadecapole moments within the same model.

In this paper, we present the linearization control of an asynchronous machine. It allows decoupling and linearization of the system without including flux orientation. This non-linear control (NLC) applied to the asynchronous machine breaks up the system into two linear and independent mono systems. The speed and the Id current controls are carried out by traditional regulators PI. A qualitative analysis of the evolution of the principal variables describing the behaviour of the global system (IM-control) and its robustness is developed by several tests of digital simulation in the final stage. Numerous tests have been performed under Simulink/Matlab to show the control system performances. In recent years, asynchronous motors are more commonly used in the control processes that require different speeds and positions. The application of techniques of modern automation in electric machines control provides obtaining very high performances. The research in respective field is focused on the application of these techniques in the machine control.

International audience; An ultrasonic propagation in cancellous bone is considered using the Biot theory modified by the Johnson et al. Numerical simulations of reflected waves in the time domain are worked out by varying the modified Biot parameters. The sensitivity of different mechanical parameters : Young modulus and the Poisson ratio of the skeletal frame and physical parameters , porosity , tortuosity and viscous characteristic length are studied showing their effect on the reflected ultrasonic waves of the bone sample. The sensitivity of the modified Biot parameters with respect to the reflected wave depends strongly on the coupling between the solid and fluid phases of the cancellous bone. We show from these simulations that some parameters such as porosity and tortuosity play an important role on reflected wave ; the remaining parameters have low sensitivity compared with the porosity and tortuosity. Experimental results for reflected waves by human cancellous bone samples are given and compared with theoretical predictions .

A particle-number projection approach in quasiparticle representation is proposed in the isovector pairing case. A new expression of the projected ground-state is proposed. It is very similar to the one used in the pairing between like-particles case. The expressions of the variance on the particle-number as well as the energy are then derived. The formalism is numerically tested using the one-level schematic model. It is shown that the numerical results of the present work are the same as those obtained using the particle representation approach: the convergence is rapid and the particle-number fluctuations are totally eliminated. Moreover the present method is less time consuming.

In this paper, the direct problem of reflected waves at the first interface of a porous medium having a rigid frame is studied. The method presented in this work is based on a temporal model of the direct problem in which a simplified expression of the reflection coefficient at Darcy's regime (low frequency range) is established using the equivalent fluid model. This expression depends only on the porosity and the viscous permeability (or the flow resistivity) of the medium. The simulated reflected wave is obtained in the time domain by convolution between the reflected operator and the incident field. Experimental results are given for samples of air-saturated plastic foams and compared with theoretical predictions.

An expression of the ground-state which describes odd mass systems within the BCS approach in the isovector neutron-proton pairing case is proposed using the blocked level technique. The gap equations as well as the energy expression are then derived. It is shown that they exactly generalize the expressions obtained in the pairing between like-particles case. The various gap parameters and the energy are then numerically studied as a function of the pairing-strength within the schematic one-level model.

We combine the exact particle-number projection method with the method of Peierls-Yoccoz in order to build the simultaneous eigen-functions of the particle number and the angular momentum operators. In the axial symmetry case, the general expression of the system energy resulting from this double projection is derived. In order to overcome the complexity of the method, the calculations are performed within the Gaussian overlap approximation. It turns out that, on the one hand, the double projection introduces a non–negligible correction of the energy of the system, and on the other hand, this correction is sensitive to the deformation. Future calculations have to therefore include an evaluation of the equilibrium deformation.

This paper concerns a time-domain model of transient wave propagation in double-layered porous materials. An analytical derivation of reflection and transmission scattering operators is given in the time domain. These scattering kernels are the medium’s responses to an incident acoustic pulse. The expressions obtained take into account the multiple reflections occurring at the interfaces of the double-layered material. The double-layered porous media consist of two slabs of homogeneous isotropic porous materials with a rigid frame. Each porous slab is described by a temporal equivalent fluid model, in which the acoustic wave propagates only in the fluid saturating the material. In this model, the inertial effects are described by the tortuosity; the viscous and thermal losses of the medium are described by two susceptibility kernels which depend on the viscous and thermal characteristic lengths. Experimental and numerical results are given for waves transmitted and reflected by double-layered porous media formed by air-saturated plastic foam samples.

The physical properties of the nuclear shape have been investigated through the charge square radius (2>) and the quadrupole (Q2) and hexadecapole (Q4) moments of the even–even neutron-rich rare-earth nuclei. The single-particle energies used are those of a deformed Woods–Saxon mean-field. The pairing effects have been included by means of an exact projection method. The model has been tested for the "ordinary" nuclei near the shell closure N = 82 and has correctly reproduced the experimental data and particularly the "Kink" effect. The study has then been extended to the neutron-rich nuclei and has shown a stability of the 2> and Q2 results for N≃100 which may be attributed to the existence of a new magic number. On the other hand, a saturation of the prolate shape appears around N = 108 for the elements Nd , Sm and Gd and near N = 102 for the Dy , Er and Yb . These observations could not be confirmed by the investigation of the hexadecapole moment.