HAL (Le Centre pour la Communication Scientifique Directe), 2019
Inorganic forms of phosphorus in soils are largely tied up by aluminium (P-Al), iron (P-Fe) or ca... more Inorganic forms of phosphorus in soils are largely tied up by aluminium (P-Al), iron (P-Fe) or calcium (P-Ca). Numerous selective extraction methods are available to evaluate the uptake of phosphorus by plants. However, a large variety of soil properties will affect the results making one single method in a selected area difficult to use and interpret. The aim of this study is to identify the methods most useful for the extraction of phosphorus in rice soils in Mali and assess which physical and chemical factors affect the results and determine the strength of the selected methods. Seven soils cultivated from the two main rice cultivation areas of Mali, i.e. Office Niger in the Niger Inland Delta and Longorola in the southernmost part of Mali are used in the study. The results obtained show that there are large differences between both soils and extraction methods in mobilised phosphorus. Bray I gave statistically identical values for the Danga soil. Bray I and DA-4 methods gave higher extraction rates on alluvial Seno type soil. Bray II gave high values on Danga, Seno aeolian and Longorola backwater soils. Bray II seems to be relatively less dependent on the physical and chemical properties (pH, organic matter).
The increasing need to replace fossil fuels as a source of energy and raw material is resulting i... more The increasing need to replace fossil fuels as a source of energy and raw material is resulting in extensive research efforts towards identifying and developing high performance materials and devices based on renewable sources. Cellulose being the most versatile and abundant biopolymer in nature is one of the obvious choices. Cellulose, due to its properties that arise from the hierarchical structure, has been used for millennia by mankind although it is currently used, in the form of microfibers, mainly in the paper and pulp industry. However, many efforts are being directed towards retrieving even smaller cellulose constituents such as nanofibers and nanocrystals (i.e., nanocellulose), which can actually be used in high performance materials. In order to do so, a better understanding of the behavior and interactions between these novel nanomaterials are required. Moreover, the combination of nanocellulose with inorganic nanoparticles bears a great potential that can open the door ...
We have investigated the chemistry of the Bogolan or mud cloth dyeing process, a traditional tech... more We have investigated the chemistry of the Bogolan or mud cloth dyeing process, a traditional technique of coloring cotton cloths deeply rooted in Mali. Textiles produced by the traditional Bogolan process, using tannin-rich plant extract and iron-rich clay-based mud, were compared using infrared (IR) spectroscopy, scanning electron microscopy (SEM) and X-ray absorption near-edge spectroscopy (XANES) with cotton fibers that were impregnated with tannin and iron salt solutions. IR spectroscopy in both reflective mode on the cloth and cotton and in transmission mode on single fibers, together with SEM, showed that gallic and tannic acid adsorb and precipitate onto the cotton fiber surface. IR spectroscopy and comparison with tannin and iron solution-impregnated cotton showed that the black color of the traditional Bogolan cloth is dominated by the formation of iron-tannin complexes. The presence of iron in the Bogolan cloth was confirmed using XANES data, supporting the notion that iro...
... Clays are also used in the dyeing technique of cotton fabric, named African Bogolanfini. It i... more ... Clays are also used in the dyeing technique of cotton fabric, named African Bogolanfini. It is a long established tradition in Mali and translates as "mud cloth". The production of Bogolan cloth involves the following procedure: The textile is white cotton washed in water and dried. ...
Inspired by the Bogolanfini dyeing technique, we report how flexible nanofibrillated cellulose (C... more Inspired by the Bogolanfini dyeing technique, we report how flexible nanofibrillated cellulose (CNF) films can be functionalized and patterned by surface-bound nanoparticles of hydrolyzable tannins and multivalent metal ions with...
Les energies d'activation liees aux processus de deshydroxylation et de reorganisation struct... more Les energies d'activation liees aux processus de deshydroxylation et de reorganisation structurale d'une argile kaolinitique, utilisee essentiellement pour la poterie au Burkina Faso, ont ete etudiees par analyse thermique differentielle (ATD), par calorimetrie directe (DSC) et par diffraction des rayons X (DRX). Pour ce qui est du processus de deshydroxylation de cette argile, les valeurs d'energie d'activation determinees par la methode cinetique de Kissinger d'une part, et par la calorimetrie directe basee sur le calcul d'aire d'autre part, sont respectivement 195kJ/mol et 66kJ/mol. En ce qui concerne le processus de reorganisation structurale de l'argile, les valeurs d'energie d'activation obtenues par les deux methodes sont de 422 kJ/mol pour la methode de Kissinger et 16 kJ/mol pour la calorimetrie directe. La comparaison des resultats obtenus par les deux methodes indique une non concordance qui serait essentiellement liee a la validite...
International Journal of Biological and Chemical Sciences, 2020
L’utilisation des fertilisants chimiques dans l’agriculture s’est fortement accentuee ce dernier ... more L’utilisation des fertilisants chimiques dans l’agriculture s’est fortement accentuee ce dernier temps au Mali. En effet l’apport regulier du diammonium phosphate (DAP) peut influencer la mobilite du zinc, car les phosphates fixent cet element. L’etude a pour but d’evaluer l’impact de l’utilisation de ce fertilisant phosphate sur la disponibilite du zinc. Ainsi pour la caracterisation, l’echantillon est analyse par plusieurs methodes physico-chimiques : la diffraction des rayons X et la microscopie electronique a balayage. Des essais d’absorption ont ete realises avec cinq pots numerotes (P0, P1, P2, P3, P4) contenant chacun 1 kg d’echantillon auxquels a ete ajoute respectivement 0 ; 2 ; 4 ; 8 et 10 g du fertilisant. D’autres essais ont ete conduits avec 3 g d’echantillons preleves dans le pot P4, auxquels ont ete applique respectivement 150 ppm, 300 ppm, 450 ppm et 600 ppm de zinc. Il ressort de ce travail que la quantite de Zn retenu est proportionnelle a celle du DAP et que la li...
Zinc deficiency is a problem in developing countries and not least so in Africa. This concerns bo... more Zinc deficiency is a problem in developing countries and not least so in Africa. This concerns both agriculture and human food provision. Zinc deficiency in soils may severely decrease yields, whereas insufficient zinc in food intake primarily affects the immune defense, notably in children. The present investigation concerned zinc availability in soils, crops, and food in the Niger inland delta in Mali. Agricultural soils are largely deficient in plant-available zinc, however, soils in close vicinity to habitation show elevated zinc concentrations. The zinc concentrations in crops are low; in rice, they are about half of reference ranges. Zinc intake assessed from a number of sampled meals was about half the recommended requirement. When zinc concentration is higher phytate was also high, which made the zinc less available. In spite of a recorded sufficient intake of iron, anemia is common and is most likely because of the high phytate concentration in the cereal-dominated diet. Increasing zinc and iron availability would be possible through the use of malting, fermentation, and soaking in food preparation. Finally, in the long run, any trace element deficiency, especially that of zinc in agricultural soils needs to be amended by addition of appropriate amounts in commercial fertilizers.
HAL (Le Centre pour la Communication Scientifique Directe), 2019
Inorganic forms of phosphorus in soils are largely tied up by aluminium (P-Al), iron (P-Fe) or ca... more Inorganic forms of phosphorus in soils are largely tied up by aluminium (P-Al), iron (P-Fe) or calcium (P-Ca). Numerous selective extraction methods are available to evaluate the uptake of phosphorus by plants. However, a large variety of soil properties will affect the results making one single method in a selected area difficult to use and interpret. The aim of this study is to identify the methods most useful for the extraction of phosphorus in rice soils in Mali and assess which physical and chemical factors affect the results and determine the strength of the selected methods. Seven soils cultivated from the two main rice cultivation areas of Mali, i.e. Office Niger in the Niger Inland Delta and Longorola in the southernmost part of Mali are used in the study. The results obtained show that there are large differences between both soils and extraction methods in mobilised phosphorus. Bray I gave statistically identical values for the Danga soil. Bray I and DA-4 methods gave higher extraction rates on alluvial Seno type soil. Bray II gave high values on Danga, Seno aeolian and Longorola backwater soils. Bray II seems to be relatively less dependent on the physical and chemical properties (pH, organic matter).
The increasing need to replace fossil fuels as a source of energy and raw material is resulting i... more The increasing need to replace fossil fuels as a source of energy and raw material is resulting in extensive research efforts towards identifying and developing high performance materials and devices based on renewable sources. Cellulose being the most versatile and abundant biopolymer in nature is one of the obvious choices. Cellulose, due to its properties that arise from the hierarchical structure, has been used for millennia by mankind although it is currently used, in the form of microfibers, mainly in the paper and pulp industry. However, many efforts are being directed towards retrieving even smaller cellulose constituents such as nanofibers and nanocrystals (i.e., nanocellulose), which can actually be used in high performance materials. In order to do so, a better understanding of the behavior and interactions between these novel nanomaterials are required. Moreover, the combination of nanocellulose with inorganic nanoparticles bears a great potential that can open the door ...
We have investigated the chemistry of the Bogolan or mud cloth dyeing process, a traditional tech... more We have investigated the chemistry of the Bogolan or mud cloth dyeing process, a traditional technique of coloring cotton cloths deeply rooted in Mali. Textiles produced by the traditional Bogolan process, using tannin-rich plant extract and iron-rich clay-based mud, were compared using infrared (IR) spectroscopy, scanning electron microscopy (SEM) and X-ray absorption near-edge spectroscopy (XANES) with cotton fibers that were impregnated with tannin and iron salt solutions. IR spectroscopy in both reflective mode on the cloth and cotton and in transmission mode on single fibers, together with SEM, showed that gallic and tannic acid adsorb and precipitate onto the cotton fiber surface. IR spectroscopy and comparison with tannin and iron solution-impregnated cotton showed that the black color of the traditional Bogolan cloth is dominated by the formation of iron-tannin complexes. The presence of iron in the Bogolan cloth was confirmed using XANES data, supporting the notion that iro...
... Clays are also used in the dyeing technique of cotton fabric, named African Bogolanfini. It i... more ... Clays are also used in the dyeing technique of cotton fabric, named African Bogolanfini. It is a long established tradition in Mali and translates as "mud cloth". The production of Bogolan cloth involves the following procedure: The textile is white cotton washed in water and dried. ...
Inspired by the Bogolanfini dyeing technique, we report how flexible nanofibrillated cellulose (C... more Inspired by the Bogolanfini dyeing technique, we report how flexible nanofibrillated cellulose (CNF) films can be functionalized and patterned by surface-bound nanoparticles of hydrolyzable tannins and multivalent metal ions with...
Les energies d'activation liees aux processus de deshydroxylation et de reorganisation struct... more Les energies d'activation liees aux processus de deshydroxylation et de reorganisation structurale d'une argile kaolinitique, utilisee essentiellement pour la poterie au Burkina Faso, ont ete etudiees par analyse thermique differentielle (ATD), par calorimetrie directe (DSC) et par diffraction des rayons X (DRX). Pour ce qui est du processus de deshydroxylation de cette argile, les valeurs d'energie d'activation determinees par la methode cinetique de Kissinger d'une part, et par la calorimetrie directe basee sur le calcul d'aire d'autre part, sont respectivement 195kJ/mol et 66kJ/mol. En ce qui concerne le processus de reorganisation structurale de l'argile, les valeurs d'energie d'activation obtenues par les deux methodes sont de 422 kJ/mol pour la methode de Kissinger et 16 kJ/mol pour la calorimetrie directe. La comparaison des resultats obtenus par les deux methodes indique une non concordance qui serait essentiellement liee a la validite...
International Journal of Biological and Chemical Sciences, 2020
L’utilisation des fertilisants chimiques dans l’agriculture s’est fortement accentuee ce dernier ... more L’utilisation des fertilisants chimiques dans l’agriculture s’est fortement accentuee ce dernier temps au Mali. En effet l’apport regulier du diammonium phosphate (DAP) peut influencer la mobilite du zinc, car les phosphates fixent cet element. L’etude a pour but d’evaluer l’impact de l’utilisation de ce fertilisant phosphate sur la disponibilite du zinc. Ainsi pour la caracterisation, l’echantillon est analyse par plusieurs methodes physico-chimiques : la diffraction des rayons X et la microscopie electronique a balayage. Des essais d’absorption ont ete realises avec cinq pots numerotes (P0, P1, P2, P3, P4) contenant chacun 1 kg d’echantillon auxquels a ete ajoute respectivement 0 ; 2 ; 4 ; 8 et 10 g du fertilisant. D’autres essais ont ete conduits avec 3 g d’echantillons preleves dans le pot P4, auxquels ont ete applique respectivement 150 ppm, 300 ppm, 450 ppm et 600 ppm de zinc. Il ressort de ce travail que la quantite de Zn retenu est proportionnelle a celle du DAP et que la li...
Zinc deficiency is a problem in developing countries and not least so in Africa. This concerns bo... more Zinc deficiency is a problem in developing countries and not least so in Africa. This concerns both agriculture and human food provision. Zinc deficiency in soils may severely decrease yields, whereas insufficient zinc in food intake primarily affects the immune defense, notably in children. The present investigation concerned zinc availability in soils, crops, and food in the Niger inland delta in Mali. Agricultural soils are largely deficient in plant-available zinc, however, soils in close vicinity to habitation show elevated zinc concentrations. The zinc concentrations in crops are low; in rice, they are about half of reference ranges. Zinc intake assessed from a number of sampled meals was about half the recommended requirement. When zinc concentration is higher phytate was also high, which made the zinc less available. In spite of a recorded sufficient intake of iron, anemia is common and is most likely because of the high phytate concentration in the cereal-dominated diet. Increasing zinc and iron availability would be possible through the use of malting, fermentation, and soaking in food preparation. Finally, in the long run, any trace element deficiency, especially that of zinc in agricultural soils needs to be amended by addition of appropriate amounts in commercial fertilizers.
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