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Your search keyword '"Georges Najjar"' showing total 3 results
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3 results on '"Georges Najjar"'

1. In vitro comparison of the color degradation of two computer-aided design/computer-aided manufacturing provisional materials: A 12-month simulation

Author

Suzanna Maria Sayegh, Maha Daou, Georges Najjar, and Elie Zebouni

Subjects
color, composite resin, computer-aided manufacturing/computer-aided manufacturing, in vitro, materials, polymethyl methacrylate, stability, temporary, Dentistry, RK1-715
Abstract

Aim: This study evaluated the color aging of two computer aided design/computer aided manufacturing (CAD/CAM) provisional materials of different compositions (polymethyl methacrylate and composite resin) after exposure to thermal aging and immersion in coffee for 3, 6, and 12 intraoral months. Setting and Design: The current in vitro study was conducted from September to December 2021 at the Craniofacial laboratory at the Saint Joseph University in Beirut, Lebanon. Materials and Methods: The shades of 2.0 mm thick, 10.0 mm in diameter disk shaped specimens of VITA CAD Temp® and Ceramill® TEMP were measured using the VITA Linearguide 3D MASTER® and a conversion table to extract the CIE LFNx01aFNx01bFNx01 values on a white background (n = 30). Statistical Analysis Used: The color differences ΔE at 3, 6, and 12 months were calculated and analyzed by repeated measures ANOVA followed by Bonferroni multiple comparisons, univariate analyses, and one sample t tests. Results: The mean ΔET1/T0, ΔET2/T0, and ΔET3/T0 values were significantly higher than the cutoff values for acceptability and perceptibility for the VITA CAD Temp® and the Ceramill® TEMP groups. In addition, the increase in ΔE overtime was significantly greater in the Ceramill® TEMP group compared to the VITA CAD Temp® group. Conclusions: The Ceramill® TEMP changed color more and faster than the VITA CAD Temp®. In addition, whether at 3, 6, or 12 months, the color variations of both materials are not only perceptible but also unacceptable compared to the initial shade.

Published
2023
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2. Urban Heat Island Mapping Based on a Local Climate Zone Classification : a Case Study in Strasbourg City, France

Author

Nathalia PHİLİPPS, Tania LANDES, Pierre KASTENDEUCH, Georges NAJJAR, Camille GOURGUECHON, Laboratoire des sciences de l'ingénieur, de l'informatique et de l'imagerie (ICube), École Nationale du Génie de l'Eau et de l'Environnement de Strasbourg (ENGEES)-Université de Strasbourg (UNISTRA)-Institut National des Sciences Appliquées - Strasbourg (INSA Strasbourg), Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Institut National de Recherche en Informatique et en Automatique (Inria)-Les Hôpitaux Universitaires de Strasbourg (HUS)-Centre National de la Recherche Scientifique (CNRS)-Matériaux et Nanosciences Grand-Est (MNGE), Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Institut National de la Santé et de la Recherche Médicale (INSERM)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Institut National de la Santé et de la Recherche Médicale (INSERM)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Réseau nanophotonique et optique, Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Centre National de la Recherche Scientifique (CNRS)-Université de Strasbourg (UNISTRA)-Centre National de la Recherche Scientifique (CNRS), and univOAK, Archive ouverte

Subjects
[SPI.OTHER]Engineering Sciences [physics]/Other, Çevre Bilimleri, Local Climate Zone, Vector-based method, [SPI.OTHER] Engineering Sciences [physics]/Other, Multiple Linear Regression, UrbanHeatIsland, LocalClimateZone, MultipleLinearRegression, VectorApproach, Urban Heat Island, General Medicine, Environmental Sciences
Abstract

The Urban Heat Island (UHI) effect is characterised by higher temperatures in cities than in rural surroundings. This phenomenon leads to increased health risks in urban dwellers, particularly in the context of global climate change. It is essential to consider its spatial variability to propose efficient UHI mitigation strategies. The Local Climate Zone (LCZ) scheme is a climate-based classification that can accurately capture UHI intensities according to the urban area characteristics. In this study, an LCZ classification has been established for the city of Strasbourg by using a vector-based method that relies on a large vector database composed of land cover and cadastral parcels data. LCZ polygons are digitized from cadastral maps, then the different LCZ parameters are calculated for each of them. Six of the ten LCZ parameters proposed in the literature have been obtained. New criteria have been added to improve the classification, i.e. a vegetation parameter (VgSF) and a compactness index (CI). A given LCZ class is then assigned to each polygon using a trapezoidal fuzzy logic model, which is completed by a decision tree. The acquired final LCZ map shows that the developed vector-based method permits obtaining relevant LCZ classification. The LCZ parameters values are subsequently used to determine a multiple linear regression (MLR) aiming to get a UHI intensity for each LCZ polygon. The resulting UHI map of the Eurométropole de Strasbourg (EMS) accurately illustrates the strong spatial heterogeneity of the phenomenon.

Published
2022
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