Green gluing of tropical wood Part III: X-Ray Photoelectron Spectroscopy (XPS) and Fourier Transform Infrared Spectroscopy (FTIR) analysis of Frake and Ayous green wood's Glue line

Green gluing of tropical wood Part III: X-Ray Photoelectron Spectroscopy (XPS) and Fourier Transform Infrared Spectroscopy (FTIR) analysis of Frake and Ayous green wood’s Glue line. Emmanuel Njungab1,2, René Oum Lissouck2,4, 5Christine Labrugère, Ntede Ngah Hippolyte2, Régis Pommier3, Louis Max Ayina Ohandja2, Joseph Noah Ngamveng1 1 Laboratory of Macromolecular Chemistry (LCMA), Faculty of science, The University of Yaoundé 1, Cameroon. 2 Laboratory of Mechanics, Materials and Structures (LMMS), ENSP, The University of Yaoundé 1, Cameroon. 3 Institute of Mechanics and Engineering (I2M-GCE), The University of Bordeaux 1, France. 4 National Centre of Scientific Research (CNRS), UMR 5295, France. 5Centre de Caractérisation des Matériaux Avancés (ICMCB, CNRS-UPR), The Université of Bordeaux 1 Abstract: We have recently succeeded to bond two tropical african woods Ayous and Frake in the green state by the glulam technique using a one component (1C-PU) polyurethane adhesive. Durable bond line was achieved and succeeds to meet the structural standard requirement. Scanning electron microscopy performs on the glue line show a good embedding of the glue on the wood fibers. X-ray photoelectron spectroscopy also referred to as Electron spectroscopy for chemical analysis (ESCA) and Fourier transform infrared spectroscopy were used to investigate the interaction of both tropical woods with adhesive. Unlike theoretical expected urethane functional group, xps analysis indicated a high proportion of non hydrolyze urea group and hydrogen bonding of nitrogen (N) at 399,5 eV and 400,5 eV respectively. This foreseen that polyurea polymers and hydrogen bond are the most probable bond to strengthen the gluline. Key words: Green gluing, Tropical woods, Sanding, 1C-PU, XPS, FTIR, Polyure

Typology of Road Accidents Related to the Default of Signaling: A Case Study of the Yaoundé-Douala Highway, Southern Cameroon

Abstract This paper highlights the typology of road accidents related to the default of signing for many accidents have occurred due to imperfect signposting along roads in Cameroon. The Yaoundé-Douala highway has been chosen for this study. Available Field data recorded during the years 2007, 2009 and 2011, have enabled the analysis of each accident. It appears that amongst the 569 accidents recorded along a section of 114 km, 108 cases (about 20%) result from the default or lack of signing. From a clinical analysis, four scenarios of accidents that occurred by collision were found on one hand, and on the other hand, seven were elaborated based on factors such as: no signposting at crossroads, the lack of vertical and/or horizontal alignmentor slightly raised bump and the deficiency of signpost for normal parking layouts or no parking at certain critical points

A decision support tool approach based on the Electre TRI-B method for the valorisation of tropical timbers from the Congo Basin: an application for glulam products

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