Optimisation of location and dimension of SMC precharge in compression moulding process

The main goal of the present study is to optimise the precharge conditions such as the precharge location and dimensions that give significant effects on the mechanical performance of composite structures manufactured by the compression moulding process. As preliminary step of optimisation, we developed a manufacturing simulation program to predict the fibre volume fraction and fibre orientation. And coupled with this simulation program and a structural analysis program, a genetic algorithm (GA) is implemented to optimise the precharge conditions. The penalty function method and the repair algorithm are modified for handling constraints. The repair algorithm is applied to a symmetric structure and an arbitrary shape structure to find optimal precharge conditions.     

Wine phenolics—analysis of low molecular weight components by high performance liquid chromatography

Low molecular weight phenolic compounds were separated by high performance liquid chromatography on hydrocarbon-bonded reverse phase packings, with a water-methanol elution gradient. Phenolic compounds were extracted from wine with ethyl acetate. A first extraction at pH 7 enabled isolation of neutral molecules (catechins, procyanidins, flavonols, aromatic alcohols); a second extraction at pH 2 was performed to extract phenolic acids. Successive injections of these two extracts in the chromatograph gave the distribution of the different phenolic compounds in the wine under analysis. Analytical data are given for low molecular weight phenolic compounds present in young red Bordeaux wines from different vine cultivars.     

Nouvelle économie et commerce électronique: mesure et démesure

What actual weight do new economy and e-commerce have in the economies of developed countries? Most of the measures suggested come from consultant firms and reflect their representations of these phenomea (which vary greatly) more than reality. Moreover, new economy and e-commerce are badly-defined notions and consequently very difficult to measure. The paper reconsiders the definition of each one of these phenomena and analyzes the efforts carried out by the National Institutes of Statistics to measure them. It argues that the New Economy or more exactly the Digital Economy presents two sides. The first can be described as the sectors producing Information and Communication Technologies (equipment and services). The weight of these sectors is evaluated in terms of employment, added value,r&d expenditures… The second side is more difficult to measure because the impact oficts on all economic activities is involved. The paper shows that the generalized diffusion oficts is making increasingly difficult to isolate a specific phenomenon named Digital Economy. E-commerce is often reduced to on line sale, i.e. the addition of a new channel to mail order sale. However on line sale which has stagnated at 1 % of retail trade is far from exhausting all the transformations induced by theicts in commercial activities. It is better to speak about electronization of trade: all types of trade, and not only mail order sale, are affected by the diffusion oficts. In these conditions, it is becoming less and less relevant to base the measurement of e-commerce on the fact it is an activity distinct from the traditional retail trade.     

RCS reduction of a conducting cone-cylinder using an active method

This paper presents an active method for reducing the radar cross section (rcs) of a perfectly conducting cone-cylinder. The active elements are four microstrip patch antennas located symmetrically along the conecylinder axis. These elements radiate a field which permit the total scattered field in the direction of the receiver to be close to zero. In each time step, the hoarded system should determine some parameters of the incident wave: the incident direction, its frequency, amplitude, and phase. Then when antennas are fed with currents of suitable amplitude and phase, they radiate an electromagnetic field in the direction of the receiver that has the same amplitude but is opposite in phase compared to the scattered field, without feeding patches. Then the total field vanishes in the direction of the receiver.     

Ultrafast Doppler imaging of blood flow dynamics in the myocardium

Imaging intramyocardial vascular flows in real-time could strongly help to achieve better diagnostic of cardiovascular diseases. To date, no standard imaging modality allows describing accurately myocardial blood flow dynamics with good spatial and temporal resolution. We recently introduced a novel ultrasonic Doppler imaging technique based on compounded plane waves transmissions at ultrafast frame rate. The high sensitivity of this ultrafast Doppler technique permits to image the intramyocardial blood flow and its dynamics. A dedicated demodulation-filtering process is implemented to compensate for the large tissue velocity of the myocardium during the cardiac cycle. A signed power Doppler processing provides the discrimination between arterial and venous flows. Experiments were performed in vivo in a large animal open chest model ( N = 5 sheep) using a conventional ultrasonic probe placed at the surface of the heart. Results show the capability of the technique to image intramyocardial vascular flows in normal physiological conditions with good spatial (200 μm) and temporal resolution (10 ms). Flow dynamics over the cardiac cycle were investigated and the imaging method demonstrated a phase opposition of flow waveforms between arterial and venous flows. Finally, ultrafast Doppler combined with tissue motion compensation was found able to reveal vascular flow disruption in ischemic regions during occlusion of the main diagonal coronary artery.     

Time-domain surface impedances of lossless Debye media

In a previous paper, a surface impedance formalism was given. Its application to interfaces modelling between homogeneous and frequency dependent media, was of great interest in the finite difference timedomain (fdtd) codes. In this paper, an extension of the method to dispersive media is presented. Applying this formalism to lossless Debye medium, the analytical expressions of the time- domain surface impedances are given. The implementation in a fdtd code permits then a numerical verification of the results in relation to the Fresnel method.     

Licence de brevet et partage du risque: Résultats de simulation

Annals of Telecommunications - Le partage du risque est une des raisons les plus souvent avancées pour expliquer les clauses financières des contrats de licence. Pour autant, aucune...     

Adhesion studies of CVD copper metallization

The adhesion of chemical vapor deposition (CVD) Cu thin films to various barriers was observed to improve with a post-deposition anneal or a physical vapor deposition (PVD) Cu flash layer on the barrier before depositing CVD Cu. The ambient exposure of the barrier before the deposition of CVD Cu has been observed to lead to degradation of adhesion in both CVD Cu seed and CVD/PVD Cu high vacuum integrated metallization schemes. The integrated CVD and PVD Cu deposition scheme exhibits better adhesion due to the inherent annealing provided during the PVD deposition which is carried out at temperatures between 300 and 400°C. We have evaluated both qualitative and quantitative tests — tape test, Stud pull test and 4-point bend test — in understanding adhesion and observed that each of these tests give different details of interface breakdown.     

Extraction and analysis of T waves in electrocardiograms during atrial flutter

Analysis of T waves in the ECG is an essential clinical tool for diagnosis, monitoring, and follow-up of patients with heart dysfunction. During atrial flutter, this analysis has been so far limited by the perturbation of flutter waves superimposed over the T wave. This paper presents a method based on missing data interpolation for eliminating flutter waves from the ECG during atrial flutter. To cope with the correlation between atrial and ventricular electrical activations, the CLEAN deconvolution algorithm was applied to reconstruct the spectrum of the atrial component of the ECG from signal segments corresponding to TQ intervals. The locations of these TQ intervals, where the atrial contribution is presumably dominant, were identified iteratively. The algorithm yields the extracted atrial and ventricular contributions to the ECG. Standard T-wave morphology parameters (T-wave amplitude, T peak-T end duration, QT interval) were measured. This technique was validated using synthetic signals, compared to average beat subtraction in a patient with a pacemaker, and tested on pseudo-orthogonal ECGs from patients in atrial flutter. Results demonstrated improvements in accuracy and robustness of T-wave analysis as compared to current clinical practice.