Mathematical modeling of CO2 TEA laser

Five and six-temperature models for the CO₂–N₂–He system are used to describe the process of the dynamic emission in the TEA CO₂ laser. All physical constants and relaxation rates related to these models are examined to estimate the output pulse parameters as a function of the input parameters. The two pumping processes implemented; empirical function and differential equation show a good agreement with the experimental data.     

3D reconstruction of road surfaces using an integrated multi-sensory approach

In this paper, we present our experience in building a mobile imaging system that incorporates multi-modality sensors for road surface mapping and inspection applications. Our proposed system leverages 3D laser-range sensors, video cameras, global positioning systems (GPS) and inertial measurement units (IMU) towards the generation of photo-realistic, geometrically accurate, geo-referenced 3D models of road surfaces. Based on our summary of the state-of-the-art systems for a road distress survey, we identify several challenges in the real-time deployment, integration and visualization of the multi-sensor data. Then, we present our data acquisition and processing algorithms as a novel two-stage automation procedure that can meet the accuracy requirements with real-time performance. We provide algorithms for 3D surface reconstruction to process the raw data and deliver detail preserving 3D models that possess accurate depth information for characterization and visualization of cracks as a significant improvement over contemporary commercial video-based vision systems.     

Calixarene-based dendrimers. Second generation of a calix[4]-dendrimer with a ‘tren’ as core

Hyperbranched calix[4] (4) and calix[4]-dendrimer (5) as a second generation (G2) of calixdendrimers have been synthesized by divergent and convergent synthesis via amidation reactions.     

The impact of lead pollution on the environment of Rabat-Sale' (Morocco)

There are numerous possible vectors of industrial lead poisoning in unprotected work environments and the areas surrounding industrial sites. In the Rabat-Salé region, ceramics is the industry which uses most lead. Galena (PbS) is used in the fabrication of some types of pottery, and other lead-based compounds are used as glaze. A second source of lead pollution is the production of some fuels, in which lead is used as an anti detonator. In order to evaluate the impact of lead contamination on the environment, our investigation is focused on the lead concentration in the atmosphere, soil and vegetation at five stations in the Rabat-Salé region. We found concentrations of lead higher than those published for any other country in the atmosphere and vegetation near the ceramics factories of Rabat-Salé. These concentrations decreased significantly as we moved away from urban areas.     

Properties of a Tetrahomodioxacalix[6]arene Derivative

The synthesis and X-ray crystalstructure of a novel tetrahomodioxacalix[6]arenehexamethylester 2 arepresented. Preliminary investigations of alkali metal ioncomplexation showed that 2 is apoor extractant with selectivity for lithium.     

Mathematical modeling of hybrid CO2 laser

A Teller–Landau six-temperature model describing the dynamic emission of single-mode TEA CO₂ laser has been adapted. This model has been also used to describe the mechanism of obtaining relatively high-power output pulses from hybrid TE-TEA or CW-TEA CO₂ laser consisting of high- and low-pressure sections. The suggested mathematical model allows to investigate the mechanism which limits the TEA oscillation to single longitudinal mode (SLM) due to the narrow gain bandwidth of low-pressure section, and also to study the effect of the laser input parameters on the smooth output laser pulse parameters. In addition, numerical solutions of non-linear rate equation system of the suggested model are quantitatively discussed. The solutions describe the radiation field intensity, the population inversion, and the energy transfer processes. The calculated values of maximum peak power, total energy in pulse, pulse width, etc. are in a very good agreement with the observed experimental values.     

Modeling and preliminary analysis of piezoelectric energy harvester based on cylindrical tube conveying fluctuating fluid

In this contribution, a novel type of piezoelectric tubular energy harvester based on fluctuating fluid pressure is investigated. Analytic model of the proposed energy harvester is built under the assumption of axisymmetric radial vibration. Exact solution of the piezoelectric vibrating tube is obtained with its output performances formulated. A series of numerical simulations are conducted to investigate the influences of geometrical parameters, input mechanical load parameters and output electrical load parameters upon the output performances of the proposed piezoelectric tubular energy harvester. The model and simulation results indicate the potential of the proposed piezoelectric tubular energy harvester. It is expected that the energy harvester be useful in powering wireless sensor network for the health monitoring of hydraulic systems, where fluid conveying pipe vibration is omnipresent.