This research compares the performance of a wood-fuelled oven,a greenhouse solar dryer and open sun drying techniques for drying of fermented cocoa beans,under the same weather conditions.The tests were implemented in...This research compares the performance of a wood-fuelled oven,a greenhouse solar dryer and open sun drying techniques for drying of fermented cocoa beans,under the same weather conditions.The tests were implemented in Bafia,in the Southwest Region of Cameroon,during the month of November 2017.Performance in drying time(number of days)and quality of the resulting beans were measured(determined using sensory measurements,sight,smell and taste).Data were also collected on the progression of weight and moisture loss in the beans during the drying process,and the ambient temperatures and relative humidity levels of the environment.Also,solar radiation levels were measured for the greenhouse solar dryer and open sun drying techniques.Results showed that during dry weather conditions the wood-fuelled oven was the fastest drying method(1 day),followed by open sun drying(4 days)and the greenhouse solar dryer(5 days).The quality of beans produced through open sun drying and in the greenhouse solar dryer had a good colour,and a pleasant chocolate smell and taste.However,the beans from the wood-fuelled oven had an overly dark colour and their smell and taste were smoky due to contamination by smoke from the oven.展开更多
Bafia Group is part of the southernmost portion of the Central African Fold Belt (CAFB) in Cameroon. The geological feature of the group is characterized by the presence of metamorphic rocks in which tourmaline had be...Bafia Group is part of the southernmost portion of the Central African Fold Belt (CAFB) in Cameroon. The geological feature of the group is characterized by the presence of metamorphic rocks in which tourmaline had been recognized among accessory minerals. In the present study, attention is focus on the tourmaline bearing quartzite to the southeast of Kombé II. Structure refinement shows that tourmaline is a Fe-dravite with the formula X(Na<sub>0.95</sub>[]<sub>0.05</sub>)Y(Mg<sub>2.39</sub>Fe<sub>0.61</sub>)Z(Al<sub>5.10</sub>Mg<sub>0.90</sub>)(BO<sub>3</sub>)<sub>3</sub>T[Si<sub>6</sub>O<sub>18</sub>](OH)<sub>3</sub>[(O,OH)<sub>0.88</sub>F<sub>0.12</sub>]. The Fe-dravite is hosted in a Ca-poor quartzite, which is made up, in addition to quartz and tourmaline, of biotite and muscovite. The structure of the dravites shows a low vacancy at the X site, which militates for a crystallization of the tourmaline at a high temperature > 750℃. This is in agreement with previous work which shows that the metamorphic peak in the associated biotite gneiss reaches 825℃. The R1 value of 1.24% means that the crystal structure of the tourmalines is of high quality. The genetical link between gold mineralization and tourmaline should stimulate exploration interest in the study area.展开更多
文摘This research compares the performance of a wood-fuelled oven,a greenhouse solar dryer and open sun drying techniques for drying of fermented cocoa beans,under the same weather conditions.The tests were implemented in Bafia,in the Southwest Region of Cameroon,during the month of November 2017.Performance in drying time(number of days)and quality of the resulting beans were measured(determined using sensory measurements,sight,smell and taste).Data were also collected on the progression of weight and moisture loss in the beans during the drying process,and the ambient temperatures and relative humidity levels of the environment.Also,solar radiation levels were measured for the greenhouse solar dryer and open sun drying techniques.Results showed that during dry weather conditions the wood-fuelled oven was the fastest drying method(1 day),followed by open sun drying(4 days)and the greenhouse solar dryer(5 days).The quality of beans produced through open sun drying and in the greenhouse solar dryer had a good colour,and a pleasant chocolate smell and taste.However,the beans from the wood-fuelled oven had an overly dark colour and their smell and taste were smoky due to contamination by smoke from the oven.
文摘Bafia Group is part of the southernmost portion of the Central African Fold Belt (CAFB) in Cameroon. The geological feature of the group is characterized by the presence of metamorphic rocks in which tourmaline had been recognized among accessory minerals. In the present study, attention is focus on the tourmaline bearing quartzite to the southeast of Kombé II. Structure refinement shows that tourmaline is a Fe-dravite with the formula X(Na<sub>0.95</sub>[]<sub>0.05</sub>)Y(Mg<sub>2.39</sub>Fe<sub>0.61</sub>)Z(Al<sub>5.10</sub>Mg<sub>0.90</sub>)(BO<sub>3</sub>)<sub>3</sub>T[Si<sub>6</sub>O<sub>18</sub>](OH)<sub>3</sub>[(O,OH)<sub>0.88</sub>F<sub>0.12</sub>]. The Fe-dravite is hosted in a Ca-poor quartzite, which is made up, in addition to quartz and tourmaline, of biotite and muscovite. The structure of the dravites shows a low vacancy at the X site, which militates for a crystallization of the tourmaline at a high temperature > 750℃. This is in agreement with previous work which shows that the metamorphic peak in the associated biotite gneiss reaches 825℃. The R1 value of 1.24% means that the crystal structure of the tourmalines is of high quality. The genetical link between gold mineralization and tourmaline should stimulate exploration interest in the study area.
