The development of the cube texture has been investigated in a Fe-50%Ni alloy undergoing recrystallization and normal grain growth by means of orientation imaging microscopy (OIMTM) and bulk texture measurements (X-ray diffraction). It is shown that both the oriented nucleation and the oriented growth mechanisms are responsible for the strengthening of the cube texture in the early stages of recrystallization in this alloy. The increase in the cube texture in the intermediate stages of recrystallization is mainly related to the high differentials in stored energy associated with cube grains. These experimental results are corroborated by way of a Monte-Carlo simulation of recrystallization based on data derived by OIM of the investigated alloy at its earliest recrystallization stages. The primary mechanism responsible for the development of the cube texture during grain growth relies on the preferential migration of the high-angle grain boundaries linked to cube grains which results from the advantage in number and size shown by cube grains when recrystallization is complete.

Slanted chiral sculptured thin films (STFs) are introduced as nano-engineered materials that are effectively periodic in two orthogonal directions. Their periodicities normal and parallel to the substrate plane are related by a slant angle. A coupled wave theory is formulated and implemented for the planewave response of a slanted chiral STF of finite thickness. Numerical results show that the nonspecular remittances and the Rayleigh-Wood anomalies due to periodicity parallel to the substrate plane are tightly coupled to the specular nature of the circular Bragg phenomenon displayed due to periodicity normal to the substrate plane. In the Bragg regime, the left- and the right-circularly polarized components of the incident plane wave are redirected in non-trivially different directions. The potential of slanted chiral STFs as narrowband circular polarization beamsplitters is established.

The aim of model reduction is to obtain the simplest model while reflecting as far as possible the dynamic behaviour of a system. First, we present the reduction method based on a complex admittance matrix [Y(s)] of the whole initial model. From which we obtain by two inversions, the matrix $[Y_{\rm red}(s)]$, which can be interpreted as a reduced network. We give an example of application of the numeric reduction method. The same method is applied with success to analytical expression of impedances kept from the quadrupole representation of heat conduction. In order to simulate easily the transient responses of analytical models, we present the development of analytical impedance in the form of an equivalent network, which is proved to be very efficient during simulations. The first application is done with a heterogeneous system made of two bars of different materials, one is made of copper and the other is made of steel. The second application is done with a more complex thermal system constituting a cooler with 7 branches. This cooler is reduced to 1, 2 and 3 nodes to obtain the simplest model while reflecting as far as possible the dynamic behaviour. This document presents a generalisation of the method of network reduction in the case where the models' impedances have analytical expressions. In this case, we show that contrary to the numerical reduction, which approximates admittances to the first order, we are free to choose the model order, whatever the kept nodes, in such a manner that the model's bandwidth is considered as sufficient. The resulting equivalent networks allow easy simulations of the transient responses thanks to standard electric network softwares. Beyond the dealt examples of analytical reduction, for industrial systems non analytically calculable but governed by an equation of heat diffusion, the structures (topologies) of the reduced models would be the same. That opens prospects to obtain thermal reduced models from an automated networking realised in CAD.

This work presents the thermal field computation of a wire getting a laser supported material cladding. We present two complementary models, based on finite volume approaches. First, we present a one dimensional model in which moving of the wire is integrated by mean of an advection term in the heat diffusion equation. It gives the mean temperature variation along the wire An analytical solution of this problem is also given. Secondly, a three-dimensional model gives the complete thermal field. These two models are confronted with experiments. The result of the first one is compared to a maximum mean temperature measuring. The second is validated by comparison with microphotography of the melted zone, and in-section micro-hardness measurements.

A closed form solution of the general case of frequency shift of a Gaussian pulse in a nonlinear power law attenuating medium of arbitrary exponent including the effect of transient radiation coupling process is presented. Also, this paper describes a simulation of the spectrum pathway in an ultrasonic A-scan. It includes transducer response, frequency dependent absorption in the test medium and radiation coupling transfer function. The measurement and simulation result has been used with the closed form solution to correct the absorption filter (attenuation coefficient). The attenuation coefficient correction for castor oil to fit the simulation result with recorded data is examined.

We have implemented a real-time numerical denoising algorithm, using the Discrete Wavelet Transform (DWT), on a TMS320C3x Digital Signal Processor (DSP). We also compared from a theoretical and practical viewpoints this post-processing approach to a more classical low-pass filter. This comparison was carried out using an ECG-type signal (ElectroCardiogram). The denoising approach is an elegant and extremely fast alternative to the classical linear filters class. It is particularly adapted to non-stationary signals such as those encountered in biological applications. The denoising allows to substantially improve detection of such signals over Fourier-based techniques. This processing step is a vital element in our acquisition chain using high sensitivity magnetic sensors. It should enhance detection of cardiac-type magnetic signals or magnetic particles in movement.

We have adapted a scanning photoluminescence (SPL) apparatus, previously developed for III-V compounds analysis, for the characterization of SiC. The PL mapping is obtained by scanning the sample, fixed to an x-y stage with 1 μm minimal step, under a doubled Ar+ laser beam (244 nm) focused by a microscope objective (×52). For this excitation the spot diameter is about 4 μm. The PL signal can be either directly detected, giving integrated PL intensity, either dispersed using a monochromator, giving spectrally resolved PL (1 nm resolution). The measurements can be realized at room temperature for near band edge studies, or at low temperature (80 K) for deep defects investigation. The gettering effect of non radiative centres by the screw dislocations in 6H-SiC is evidenced using this apparatus.

This paper presents a original method for open magnetic cores modelling. It is called the distributed point source method. It is based on a spatial distribution of point sources located on the core surfaces emitting the magnetic flux, called the active surfaces. Compared to Finite Elements methods, the DSPM method requires only the meshing of these active surfaces, which considerably reduces the solving process time. In this paper, the DSPM method is applied on a magnetic cylindrical core, placed in free space.

A new pulsed laser beam equipment dedicated to the characterization of integrated circuit is presented. Using ultra-short laser pulses is a convenient way to simulate experimentally the spatial environment of integrated circuits when interactions with heavy ions occur. This experimental set-up can be considered as a complementary tool for particle accelerators to evaluate the hardness assurance of integrated circuits for space applications. These particles generate temporally electrical disturbance called Single Event Effect (SEE). The theoretical approach of an equivalence between heavy ions and a laser pulses is discussed. The experimental set-up and some relevant operational methodologies are presented. Experimental results demonstrate that the induced electrical responses due to an heavy ion or a laser pulse are quite similar. Some sensitivity mappings of integrated circuits provided by this test bench illustrate the capabilities and the limitations of this laser-based technique. Contrary to the particle accelerators, it provides useful information concerning the spatial and temporal dependences of SEE mechanisms.

An analytical method based on a fractal geometry concept was developed through the relationship between structure-texture of solid-like crackers, flat bread and Bretzels. An universal testing machine was used to determine indentation tests. The graphs were irregularly shaped so that usual interpretation was made not possible. Nevertheless, the irregular shape, or “roughness” displays auto-similarity properties which can be interpreted in terms of apparent fractal dimension texture (DT). A trained panel able to quantify the “hardness”, “porous structure” and “crispness” descriptors carried out sensorial characterisation of products. High correlation between sensorial hardness and resistance to indentation, on one hand, and between crispness and DT on the other hand was found. Modelling mathematics methods for complex systems allow useful contribution to Food Science.