University of the Littoral Opal Coast

About: University of the Littoral Opal Coast is a education organization based out in Dunkirk, France. It is known for research contribution in the topics: Catalysis & Dielectric. The organization has 1242 authors who have published 2383 publications receiving 46230 citations. The organization is also known as: ULCO.

Multipoint Relaying Versus Chain-Branch-Leaf Clustering Performance in Optimized Link State Routing-Based Vehicular Ad Hoc Networks

Abstract: Routing protocols for vehicular ad hoc networks resort to clustering in order to optimize network performance. Concerning the optimized link state routing protocol and the plethora of its derivatives, the multipoint relaying (MPR) technique has proven its efficiency as an accurate clustering scheme over the last two decades. However, it has been emphasized recently that the MPR technique, which was originally designed for open areas, does not benefit from the particular configuration of road sections, which are intrinsically spatially constrained. A clustering scheme exploiting this particularity, namely chain-branch-leaf (CBL), has been introduced in order to enhance the flooding of broadcast traffic, including that related to routing operations. In this paper, both MPR and CBL are evaluated through MATLAB simulation over several scenarios based on realistic road configurations and traffic generated with SUMO simulator. The results show that CBL actually reduces the number of nodes acting as relays (cluster-heads) in the network, thus decreasing the routing traffic related to creation and retransmission of topology control messages. Also, they show that, with CBL, the nodes chosen as relays remain longer in this role, thus favoring the overall network stability, and that most of the nodes remain attached longer to the same relay than with the MPR technique.

Workplace Exposure to Nanoparticles during Thermal Spraying of Ceramic Coatings

Abstract: Thermal spraying is widely used for industrial-scale application of ceramic coatings onto metallic surfaces. The particular process has implications for occupational health, as the high energy process generates high emissions of metal-bearing nanoparticles. Emissions and their impact on exposure were characterized during thermal spraying in a work environment, by monitoring size-resolved number and mass concentrations, lung-deposited surface area, particle morphology, and chemical composition. Along with exposure quantification, the modal analysis of the emissions assisted in distinguishing particles from different sources, while an inhalation model provided evidence regarding the potential deposition of particulate matter on human respiratory system. High particle number (>10(6) cm-3; 30-40 nm) and mass (60-600 µgPM1 m-3) concentrations were recorded inside the spraying booths, which impacted exposure in the worker area (10(4)-10(5) cm-3, 40-65 nm; 44-87 µgPM1 m-3). Irregularly-shaped, metal-containing particles (Ni, Cr, W) were sampled from the worker area, as single particles and aggregates (5-200 nm). Energy dispersive X-ray analysis confirmed the presence of particles originated from the coating material, establishing a direct link between the spraying activity and exposure. In particle number count, 90% of the particles were between 26-90 nm. Inhaled dose rates, calculated from the exposure levels, resulted in particle number rates (n˙) between 353 × 10(6)-1024 × 10(6) min-1, with 70% of deposition occurring in the alveolar region. The effectiveness of personal protective equipment (FPP3 masks) was tested under real working conditions. The proper sealing of the spraying booths was identified as a key element for exposure reduction. This study provides high time-resolved aerosol data which may be valuable for validating indoor aerosol models applied to risk assessment.

Development of a competitive continuous variation plot for the determination of inclusion compounds stoichiometry

Abstract: The spectral displacement method in presence of methyl orange has been coupled to the continuous variation plot to allow the determination of the stoichiometries for inclusion compounds. Such a “competitive continuous variation plot” (CCV plot) is especially useful for the study of substrates which are not directly observable by spectroscopy or which are too poorly soluble to give observable signals. Moreover, when a mixture of complexes is observed, the position of the maximum in the competitive continuous variation plot gives information on the relative affinities of the complexes, which is not the case in the classical Job plot which also depends of the intrinsic spectral characteristics of each complex. The method is not restricted to β-cyclodextrin inclusion compounds, and it may be applied to any complexes if an appropriate competitive system is available.

Laser spectroscopic monitoring of gas emission and measurements of the 13C/12C isotope ratio in CO2 from a wood-based combustion

Abstract: We report on the application of a compact and field-deployable instrument, based on a continuous-wave fiber-coupled Telecom external cavity diode laser, to measure the 13C/12C isotope ratio in CO2 from a wood-based combustion. Carbon dioxide, the most important greenhouse gas, is a major product of combustion. The measurements of the 13C/12C isotopic ratio in CO2 from combustion emission permit one to identify the CO2 source and to study the temporal and spatial variations of pollution in the atmosphere. The average value of the 13CO2/12CO2 ratio is found to be (1.1011±0.0024)%. The corresponding δ-value relative to PDB standard is (−20.17±2.14)‰, which is in good agreement with the typical value of (−25±2)‰ for wood. Simultaneous monitoring of multiple species from gas emission has been performed using direct-absorption spectroscopy. The concentrations of C2H2, CO, CO2 and H2O were determined on the basis of integrated absorbance measured by least-squares fitting a Voigt lineshape to experimental absorption spectra.