Using electron-induced X-ray emission spectroscopy (XES), we have studied two Al/Ni periodic multilayers that differ only by their annealing temperature: as-deposited and annealed at 115 °C. Our aim is to show that XES can provide further details about the chemistry at the metal-metal interface, in addition to what is obtained by X-ray diffraction. The distribution of valence states exhibiting Al 3p and Ni 3d character is determined from the analysis of the Al $K\beta$ and Ni $L\alpha$ emission bands respectively. The multilayer emission bands are compared to those of reference materials: pure Al and Ni metals as well as Al3Ni, Al3Ni2 and AlNi intermetallics. We provide evidence that, for temperatures up to 115 °C, Al3Ni is the major component of the multilayer.

Kidney stones consist of various organic, inorganic and semi-organic compounds. Mineral oxalate monohydrate and di-hydrate is the main inorganic constituent of kidney stones. However, the mechanisms for the formation of crystal mineral oxalate are not clearly understood. In this field of study there are many hypothesis including nucleation, crystal growth and or aggregation of formation of AOMH (ammonium oxalate monohydrate) and AODH (ammonium oxalate di-hydrate) crystals. The effect of some urinary species such as ammonium oxalates, calcium, citrate, proteins and trace mineral elements have been previously reported by the author. The kidney stone constituents are grown in the kidney environments, the sodium meta silica gel medium (SMS) provides the necessary growth simulation (in vitro). In the artificial urinary stone growth process, growth parameters within the different chemical environments are identified. The author has reported the growth of urinary crystals such as CHP, SHP, BHP and AHP. In the present study, BaNH4MgHPO4 (barium ammonium magnesium hydrogen phosphate) crystals have been grown in three different growth faces to attain the total nucleation reductions. As an extension of this research, many characterization studies have been carried out and the results are reported.

The effect of β-irradiation on silicate and aluminoborosilicate glasses doped with transition metals (TM) and rare earth (RE) elements has been studied using Electron Paramagnetic Resonance (EPR), Raman and luminescence spectroscopy. Irradiation leads to the reduction of both Cr and Mn ions in both types of glass matrix. It is shown that even small amounts of TM dopants completely block defect production, as occurs under irradiation in non-doped glasses. As well, TM doping results in the disappearance of structural changes in the glass (densification, polymerization increase and Na migration) for doses of ~ 109 Gy. Unlike TM-doped matrices, incorporation of RE ions into aluminoborosilicate glass blocks neither defect production nor structural changes in glass matrices during irradiation. Simultaneously, we observe a reduction of RE ions, most clearly demonstrated for Ce4+ ions in aluminoborosilicate glasses. We propose that the relative stability of the different charge states of the RE ions is linked to the efficiency of the reduction process, and therefore to the evolution of the glass structure during irradiation.

This paper displays some simulation results of dynamic responses of the high-T c superconductors (HTSC)-Permanent magnet (PM) levitation systems taking into account the influence of the flux creep phenomena and of the thermal effect. We focus on the establishment of a three-dimensional numerical code to solve the nonlinear and coupled equations. A new control volume method is proposed for the resolution of the partial derivative equations of the treaded physical phenomena. The influence is comprehensively displayed by comparing the predictions of dynamic responses of such systems in which the thermal effect in the superconductor is and is not taken into account. The electromagnetic and thermal coupling is ensured by an alternate algorithm. The thermal effect highlights the influence of the temperature on the value of the magnetic levitation force, levitation stabilization time and shows that the vibration center of levitated body had drifted downward.

A binary Sn-5wt.%Sb solder alloy was chosen as a potential alternative to Sn-Pb solder alloy to be subjected to many studies. It was casted from the liquid state, cold drawn into wires of 1 mm diameters. The study includes the structure, electrical resistivity, tensile strength, hardness and indentation creep behavior using XRD, four probes electrical circuit, conventional tensile testing machine, Vickers microhardness tester, respectively. These properties were carried out for the cold worked alloy and after annealing at 393 and 473 K for 60 min. It was found that annealed samples exhibit more precipitations of the intermetallic compounds SnSb, higher lattice parameters and higher crystallite size, while have lower lattice-strain induced due to the cold working process. These structural changes greatly affect the electrical resistivity and mechanical properties of this alloy.

PET (Poly ethylene terephthalate) fabric was treated using dielectric barrier discharge (DBD) as a type of low temperature plasma under atmospheric pressure for 1 to 15 min and different powers ranging between 0.3 to 5 W. Effects of DBD treatment on the surface of a test PET fabric are examined, reported and discussed. The surface analysis and characterization were performed using X-ray diffraction (XRD), Fourier transition infrared spectroscopy (FTIR) and scanning electron microscopy (SEM) before and following the DBD processing. SEM analysis shows significant surface morphology changes in plasma treated polyester fabric surface, while FTIR analysis indicates that the reactivity of the surface was increased. The discharge parameters used are correlated with the changes in the surface characteristics found after DBD processing of various durations, in atmospheric air environment.

The dynamics of gas heating in fast pulsed discharges in nitrogen-oxygen mixtures was analyzed using a state-specific plasmachemical model and an energy conservation equation. It was shown that the heating rate changes over time according to the changes of the species involved in the heating processes. An increasing dependence on time was shown. The results show that higher electron density, electric field or partial pressure of oxygen leads to a faster gas heating. However, the heating rate associated with excitation of vibrational and electronic degrees of freedom is almost independent of the value of the applied field in the studied range of fields.

Optical Emission Spectroscopy (OES) is used to investigate the effect of argon gas mixing on the electron temperature, the degree of nitrogen dissociation and the active species concentration in a 13.56 MHz radio frequency (RF) sustained nitrogen plasma. The electron temperature is determined from Ar-I emission line intensities by using the modified Boltzmann's plot method and is found to be increased with argon mixing in nitrogen plasma. The concentration of active species $\rm N_2(C ^3\Pi_{\it u})$ and $\rm N_2^+ (B ^2\Sigma_{\it u}^+)$ is monitored in terms of the emission intensities of nitrogen (0–0) bands of the second positive and the first negative systems respectively. The concentration of $\rm N_2 (C^3\Pi_{\it u})$ active species along with the degree of N2-dissociation is appreciably enhanced by argon mixing signifying the role of argon metastables in the excitation and dissociation processes.

We demonstrate a simple approach for a difference-frequency synthesiser within the terahertz domain. Two near-infrared CW diode lasers are frequency-locked to the resonances of a high finesse Fabry-Perot cavity using the Pound-Drever-Hall technique. Two acousto-optic modulators driven by RF synthesizers frequency-shift each diode laser and provide continuous tuning, modulation and switching capabilities for the difference-frequency. Terahertz-waves generated by heterodyne mixing in an ultrahigh-bandwidth photodetector are used to interrogate the rotational transitions in the ground state of themethyl-chloride.

In this paper, several empirical and semiempiricalmodels are used to describe the formative time delay dependence onworking voltages t f   (U) in neon at the pressure of13.3 mbar. Besides our models, the empirical and theoreticalmodels from the literature are successfully applied to theexperimental data, without and with empirical corrections on thebasis of our analysis. Good agreements with experimental data werefound primarily at low overvoltages and with empiricalcorrections even at high overvoltages. The statistically basedmeasurements of the breakdown time delayare shown to be convenient for the study of the formative timedelay under different conditions.

We describe a method and present the results of the measurements ofspectral change of stored ultra-cold neutrons and the sub-barrier neutronup-scattering from solid surfaces to the energy range higher than theboundary energy of the sample. The method consists in measuring the neutron absorption curvesas a function of UCN storage time and the thickness of the absorbers. The quasi-elastic and inelastic UCN up-scattering probability is determinedat room temperature. The neutron spectra are inferred in monochromatic and more detailedapproximations.

The polyvinylidenefluoride (PVdF) based novel polymer electrolytes have been prepared by solution casting technique for solid state rechargeable magnesium batteries. Tetraglyme and tetrabutyl ammoniumchloride were used respectively as plasticizer and filler. The Mg(ClO $_{4})_{4}$ was used as conducting source. A.c. impedance spectroscopy results reveal that 5 wt% TBACl containing electrolyte show the maximum conductivity of 4.32 × 10-4 S/cm at ambient temperature. This electrolyte was electrochemically stable upto 1.5 V which was observed through linear sweep voltammetry. X-ray diffractograms studies suggest that the electrolytes are completely in amorphous phase. The improved entanglement like surface morphology was well observed for 5 wt% TBACl containing electrolyte by scanning electron microscope. The activation energy and coherence length were calculated.

The objective of this work was to propose and assess, under the light of modern techniques for arc visualization and welding parameter monitoring, a parameter that would quantify properly the effect of the droplets reaching the pool over the bead penetration during MIG/MAG welding (GMAW). High-speed filming shadowgraphy, synchronized with the electrical signals, was used. Dedicated computational programs were employed to measure arc lengths and size, frequency, acceleration and speed of the droplets. Calibration of the system by employing metallic spheres was used to guaranty the performance of the image recording and measurement programs. Statistics were employed for sampling size determination. A non-common approach to correlate Momentum to bead geometry is propose and discussed. The methodology was assessed through MIG/MAG bead-on-plate welds shielded with an Ar+5%O2 blend, at three levels of currents and arc lengths. It was concluded that the proposed parameter denominated in this paper as “Effective Momentum” is the one which better represents the action of the droplets over bead formation.

This paper investigates the influence of static magnetic field exposure on blood flow. We mainly focus on steady flows in a rigid vessel and review the existing theoretical solutions, each based on some simplifying hypothesis. The results are developed, examined and compared, showing how the magnetohydrodynamic interactions reduce the flow rate and generate electric voltages across the vessel walls. These effects are found to be moderate for magnetic fields such as those used in magnetic resonance imaging. In this case, a very simplified solution, formulated by neglecting the walls conductivity as well as the induced magnetic fields, is proven suitable.


In this paper, we are interested in the transition between regimes where either visco-thermal or multiple scattering effects dominate for the propagation of acoustic waves through a 2D regular square array of rigid cylinders embedded in air. An extension of the numerical method using Schlömilch series is performed in order to account for visco-thermal losses. Comparison with experimental data and results from classical homogenization theory allows to study the transition between a low frequency limit (where viscous and thermal effects dominate) and a high frequency regime (where multiple scattering effects become predominant). For this particular geometry, a large frequency domain where visco-thermal and multiple scattering effects coexist is found.