Optical emission spectroscopy is used to characterize the production of active species as a function of hydrogen concentration in the mixture under different operating conditions. A major concern is to enhance the concentration of the active species by hydrogen addition that carry several electron volts energy above their ground states, and thus affect the surface chemistry. The emission intensity of the selected optical transitions of molecular and atomic species is measured to determine the functional dependence of their radiative states. The relative ground state molecular ion density [N2 +]is measured from the emission intensity of the first negative band head (λ = 391.4 nm, 0–0) by considering the fact that in low temperature plasma, ion with single charge is produced by the electron impact, and the ion density is proportional to the electron density. It is found that the concentration of the active species may be enhanced significantly by selecting an appropriate gas composition and operating parameters. The SS-304 samples are nitrided under the optimum conditions for 4, 8, 12 and 16 hours and hardness values are found to increase five times for 16 hours treatment time. The optimized discharge conditions are found favorable for plasma ion nitriding.

Polystyrene thin films undergo treatment by cold plasma produced from DC point-to-plane low- pressure (4 mbar) discharge in O2 and Ar. The surface tension highly increases (more than 70% for O2 plasma and 60% for Ar plasma) by applying as weak as 200 μA discharge mean current. The treatment time required for obtain the maximum wettability is double in the case of Ar (~60 s). Important increase in surface polar component takes place while the dispersive component decreases, regardless of the gas used. Oxygen-functionalities (10–12%) graft the first 5 nm of surface and the surface polarity is decupled, in both gases. The main part (>99.8% for O2 and >97% for Ar) of the treatment time corresponds to a relaxation phase of the discharge (post-discharge time) and, thus, the role of long lifetime excited particles (>3 eV) in the activation of the polymer surface is emphasized. An ionization front having velocity ~104–106 m/s (higher in O2 than in Ar) crosses the gap starting from the anode and propagating towards the cathode. The arrival of this wave at the cathode region boosts the cathode secondary processes. The secondary electrons amplify the discharge current and trigger off the initiation of a new ionization front, stronger than the first one, which establishes the glow discharge regime. These fronts (weaker in Ar discharge) are suggested as the main mechanisms for the cold plasma production and active particles generation for the polymer treatment.

This paper presents a study of the ultrasonic wave propagation in a cylindrical layer-substrate structure of an infinite length. We determine the dispersion curves of the structure, the displacements field in the structure and the impact of the contact quality between the layer and the substrate. The industrial application aimed by our study is the control of the massive machine elements with cylindrical cavities coated and exposed to corrosion. The obtained results show that some modes of propagation are insensitive to the layer thickness. Therefore, these modes can be generated during the ultrasonic control of the layer. In addition, for the dimensions considered here, the second mode of propagation is the most adapted for the detection of defects in the vicinity of the internal layer wall. In addition, our study shows the possibility of characterization of the quality of contact between the layer and the substrate from the analysis of dispersion curves of the structure.

We present the new advances in ultra-stable microwave oscillators recently obtained at the department LPMO of the Institut FEMTO-ST Besançon. These microwave references are based on Sapphire Whispering Gallery Mode Resonators presenting high-Q factor. Different technologies have been developed with these resonators to fulfill the new requirements in term of phase noise or frequency stability for diverse scientific and technical applications.

This paper presents a study of guided ultrasonic waves in a tri-layer structure composed of two aluminum sheets bonded by an adhesive layer of resin epoxy. Numerical resolution, of high accuracy, of the characteristic equation permitted to determine the dispersion curves and the displacements field in the structure. A new interpretation of the dispersion curves of the tri-layer structure is proposed highlighting the existence, for each propagation mode, of a portion where this mode follows the mode of an adhesive layer and another portion where it follows the mode of an aluminum sheet. From dispersion curves, we determine the displacements field of the tri-layer structure showing that the displacement takes place in the adhesive layer when the mode of propagation is in the first portion and it is dominating in the aluminum sheets if the mode is in the second portion. In addition, we show the possibility of characterization of the quality of bond of the two aluminum sheets from the analysis of dispersion curves of the structure.

The anterior cruciate ligament (ACL) is the major articular ligamentous structure of the knee, it functions as a joint stabilizer. When ruptured, the natural ACL ligament can be replaced by a textile synthetic ligament such as a braid, knitted cord, or woven cord. Theses structures are composed of biocompatible materials such as polyester or Gore-Tex filaments. The success of an ACL replacement is widely linked to its mechanical and dimensional properties such as tensile strength, dimensional stability and resistance to abrasion. We introduced an additional treatment in the manufacturing of textile ACL ligaments based on the thermofixation of the textile structure by using textile industry stabilization techniques. Boiling water, saturated vapor and dry heat have been tested to stabilize a braided ligament made of Dacron polyester. The application of these three techniques led to shrinkage and an increase of breaking strength of the textile structure.

We estimated the temperature of the gas phase surrounding a Y2O3 sample melted at the focus of a solar furnace by comparing the fluorescence spectra of YO molecule A2 Π 1/2-X2 Σ +, A2 Π 3/2-X2 Σ +, B2 Σ +-X2 Σ + systems and simulated spectra (two temperature model). If A3/2 and B systems can be described by a simple formulation for the calculation of upper and lower states energies, we have had, despite the poor resolution of our instrument, to use a full formulation and particularly introduce the Λ doubling terms, to satisfactorily describe the A1/2 system. At low pressure the discrepancies between rotational and vibrational temperatures and the weakness of the fits suggest that the populations of internal levels do not follow Boltzmann distributions mainly close to the vaporizing surface. The temperatures determined at higher pressures (50 hPa) on the three systems are consistent each others and supposed representative of that of the gas phase.

The aim of this work is to present a new indirect and noninvasive method for the measurement of the Newtonian blood viscosity. Based on an integral form of the axial Navier-Stokes equation, this method is particularly suited for in vivo investigations using ultrasonic arterial blood velocity profiles. Its main advantage is that it is applicable to periodic as well as non periodic flows. Moreover it does not require classical filtering methods enhancing signal to noise ratio of the physiological signals. This method only requires the knowledge of the velocimetric data measured inside a spatially and temporally optimized zone of the Doppler velocity profiles. The results obtained using numerical simulation as well as in vitro or in vivo experiments prove the effectiveness of the method. It is then well adapted to the clinical environment as a systematic quasi on-line method for the measurement of the blood viscosity.

We introduce a method to measure liquid absorption into paper based on measuring white light reflected from it. The method was used with 49.8–51.7 g/m2 pilot papers, whose hydrophobicity was tuned by their fiber content and furnish. In addition, one of the samples was internally sized. Impact wetting was used where a droplet of mineral oil, isopropanol or deionized water was applied to the paper surface opposite to the one facing the monitor. The volume of liquid per droplet was (0.9±0.2) μl to (1.3±0.1) μl. The sample was illuminated with an ordinary 20 W light bulb from above. The light intensity reflected off the sample was recorded with a fast charge-coupled camera during the liquid penetration. Optical changes in the paper sample were studied by calculating the average intensity of the reflected light from a selected area. The results showed that the speed of pore wetting, mainly in the z-direction, could be measured with each liquid-sample combination. Hence a digital camera based light reflection measurement can provide information about thickness direction liquid transport in paper.