It is known that large amounts of residual lignin are generated in the pulp and paper industry.A new alternative for Kraft lignin valorization,which consists of first a chemical modification using a diisocyanate and t...It is known that large amounts of residual lignin are generated in the pulp and paper industry.A new alternative for Kraft lignin valorization,which consists of first a chemical modification using a diisocyanate and then the efficient dispersion in castor oil to achieve stable gel-like systems,is proposed in this work.Rheological properties and microstructure of these materials were determined by means of small amplitude oscillatory shear tests and viscous flow measurements and atomic force microscopy observations,respectively.Moreover,both standardized penetration tests and tribological assays,usually performed in the lubricant industry,were carried out to evaluate the performance characteristics as lubricating greases.Linear viscoelasticity functions are affected by the lignin/diisocyanate ratio and thickener concentration.The thermorheological response evidenced a softening temperature of around 105°C.The microstructure of these gel-like dispersions is composed of interconnected thin fibers,homogeneously distributed in castor oil.Moreover,the NCO-functionalized lignin gel-like dispersions studied show lower friction coefficients than traditional lubricating greases.展开更多
We examined demand and supply of Food Tree Species (FTS) products in Burkina Faso. The hypotheses were: 1) demand for FTS products by local communities exceeds what can be sustainably extracted, and 2) local communiti...We examined demand and supply of Food Tree Species (FTS) products in Burkina Faso. The hypotheses were: 1) demand for FTS products by local communities exceeds what can be sustainably extracted, and 2) local communities of the Sudanian zone have access to more diverse FTS products compared to Sahelian zone. Surveys were conducted in 300 households and 360 quadrats in landscapes surrounding 6 villages to determine the diversity, richness and availability of FTS. The results indicate that local communities tend to exploit FTS which are rare to find or absent in the landscape surrounding their village. While the range of FTS largely exploited tends to coincide across the two ecological zones, the diversity and density of the preferred FTS are discordant between the two zones. The results of the present study further support the need for conservation and restoration strategies to sustain the local communities demand for FTS products.展开更多
文摘It is known that large amounts of residual lignin are generated in the pulp and paper industry.A new alternative for Kraft lignin valorization,which consists of first a chemical modification using a diisocyanate and then the efficient dispersion in castor oil to achieve stable gel-like systems,is proposed in this work.Rheological properties and microstructure of these materials were determined by means of small amplitude oscillatory shear tests and viscous flow measurements and atomic force microscopy observations,respectively.Moreover,both standardized penetration tests and tribological assays,usually performed in the lubricant industry,were carried out to evaluate the performance characteristics as lubricating greases.Linear viscoelasticity functions are affected by the lignin/diisocyanate ratio and thickener concentration.The thermorheological response evidenced a softening temperature of around 105°C.The microstructure of these gel-like dispersions is composed of interconnected thin fibers,homogeneously distributed in castor oil.Moreover,the NCO-functionalized lignin gel-like dispersions studied show lower friction coefficients than traditional lubricating greases.
文摘We examined demand and supply of Food Tree Species (FTS) products in Burkina Faso. The hypotheses were: 1) demand for FTS products by local communities exceeds what can be sustainably extracted, and 2) local communities of the Sudanian zone have access to more diverse FTS products compared to Sahelian zone. Surveys were conducted in 300 households and 360 quadrats in landscapes surrounding 6 villages to determine the diversity, richness and availability of FTS. The results indicate that local communities tend to exploit FTS which are rare to find or absent in the landscape surrounding their village. While the range of FTS largely exploited tends to coincide across the two ecological zones, the diversity and density of the preferred FTS are discordant between the two zones. The results of the present study further support the need for conservation and restoration strategies to sustain the local communities demand for FTS products.
