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Yapo B.M.,Charles Sadron Institute | Koffi K.L.,Felix Houphouet-Boigny National Polytechnic Institute
Carbohydrate Polymers | Year: 2013

Calcium-mediated gelation of LMP is thought to arise from formation of a dense network of Ca2+-cross-linked DMB meeting a required minimum average length along pectin chains. The use of MP containing specific average DMB size (BS) types, in the range of 3-100 and in varying proportion (0-100%), has afforded further insights into the gelling behaviour of pectins with a certain DM in the presence of Ca2+ ions. It clearly appeared that a required minimum BS and a required minimum average frequency (BSF) of the required minimum BS are conditions that must be satisfied by a pectin for formation of a highly dense Ca2+-cross-linked DMB network equaling an elastically stable, strong, and cohesive gel. Furthermore, there is a clear contribution of the pectin branched domains to gelation and formation of a firmer and more cohesive gel. The results suggest that this pectin portion may function, not only as a "maintainer" of the pectin molecular weight to a sufficiently high level which fosters good gelation regarding the gelling rate and the strength and nature of the gel formed, but also as junction-zone-terminating structural elements that limit the appearance of undesirable phenomena, notably turbidity, syneresis, and precipitation. © 2012 Elsevier Ltd. All rights reserved. Source


Sebe G.,CNRS Organic Polymer Chemistry Laboratory | Ham-Pichavant F.,CNRS Organic Polymer Chemistry Laboratory | Ibarboure E.,CNRS Organic Polymer Chemistry Laboratory | Koffi A.L.C.,Felix Houphouet-Boigny National Polytechnic Institute | Tingaut P.,Empa - Swiss Federal Laboratories for Materials Science and Technology
Biomacromolecules | Year: 2012

Cellulose II nanowhiskers (CNW-II) were produced by treatment of microcrystalline cellulose with sulfuric acid by both controlling the amount of H 2SO 4 introduced and the time of addition during the hydrolysis process. The crystalline structure was confirmed by both XRD and 13C CP-MAS NMR spectroscopy. When observed between crossed polarizers, the cellulose II suspension displayed flow birefringence and was stable for several months. The CNW-II nanowhiskers were significantly smaller than the cellulose I nanowhiskers (CNW-I) and had a rounded shape at the tip. The CNW-II average length and height were estimated by AFM to be 153 ± 66 and 4.2 ± 1.5 nm, respectively. An average width of 6.3 ± 1.7 nm was found by TEM, suggesting a ribbon-shape morphology for these whiskers. The average dimensions of the CNW-II elementary crystallites were estimated from the XRD data, using Scherrer's equation. A tentative cross-sectional geometry consistent with both XRD and NMR data was then proposed and compared with the geometry of the CNW-I nanowhiskers. © 2012 American Chemical Society. Source


Iritie B.G.J.J.,Felix Houphouet-Boigny National Polytechnic Institute
Journal of Sustainable Development | Year: 2015

From the economic literature on the relationship between economic growth and environment pioneered by Grossman and Krueger (1991) and Shafik and Bandyopadhyay (1992) we first conduct a theoretical and critical reflection on the existence of a Kuznets curve for biodiversity. It appears that results are strongly contrasted; economic growth does not seem to be necessarily the solution of biodiversity loss. Then, we focus on the main biodiversity conservation policies implemented in Africa (with the example of Côte d'Ivoire), i.e. protected areas and we discuss its effectiveness in achieving the dual objective of conservation and economic development for local communities. © 2015 by the authors. Source


Konin A.,Felix Houphouet-Boigny National Polytechnic Institute
Research Journal of Applied Sciences, Engineering and Technology | Year: 2012

This study aims to study the effect of type of binder on properties of mortars with coir. Two types of binders were used for the manufacturing of mortars containing coir: lime is used as binder for mortar n°1 (Mortar 1) and cement is used for mortar n°2 (Mortar 2). The measurements of the physical, mechanical and thermal properties of the specimens show that Mortar 1 has higher water absorption values than those of Mortar 2 and consequently has the lowest values of thermal conductivity. The results also indicate that dry density of the specimens has more important role than the type of binder on mechanical properties. Relationships were established between mechanical properties and dry density of these mortars. These relationships are independent to the type of binder. The mortars also satisfied most recommended thermal insulation standards. © Maxwell Scientific Organization, 2012. Source


Konin A.,Felix Houphouet-Boigny National Polytechnic Institute
ARPN Journal of Engineering and Applied Sciences | Year: 2012

This paper aims to study the effect of type of binder on properties of mortars with coir. Two types of binders were used for the manufacturing of mortars containing coir: lime is used as binder for mortar n°1 (Mortar 1) and cement is used for mortar n°2 (Mortar 2). The measurements of the physical, mechanical and thermal properties of the specimens show that Mortar 1 has higher water absorption values than those of Mortar 2 and consequently has the lowest values of thermal conductivity. The results also indicate that dry density of the specimens has more important role than the type of binder on mechanical properties. Relationships were established between mechanical properties and dry density of these mortars. These relationships are independent to the type of binder. The mortars also satisfied most recommended thermal insulation standards. © 2006-2012 Asian Research Publishing Network (ARPN). Source

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