Jatropha curcas Linn has been identified worldwide as one of the sources of biodiesel. Biodiesel has energy properties close to fossil diesel and can be a potential energy alternative. However, these properties may va...Jatropha curcas Linn has been identified worldwide as one of the sources of biodiesel. Biodiesel has energy properties close to fossil diesel and can be a potential energy alternative. However, these properties may vary based on soils, plant genetics and agro-climatic conditions in a given geographical location. Several studies on biodiesel production under such conditions have been done elsewhere, but few have been done on J. curcas oil in Uganda. This study analysed the physicochemical properties of J. curcas L. oil for biodiesel production in Nebbi and Mukono districts using American Standards and Testing Methods (ASTM D6751) and European Standards (EN 14214). J. curcas seed kernel contained 51% w/w and 48% w/w of oil with high levels of Free Fatty Acids (1.52% and 1.93%) and acid values (35 and 36 mg KOH/g) for Nebbi and Mukono, respectively;the difference was significant (p ≤ 0.05). Generally, the quality and quantity of the oil from Nebbi were better than those of Mukono, based on the biodiesel standard values. Nevertheless, kinematic viscosity, acidity, potassium and phosphorus content values were found abnormally high (31.46 - 33.23 mm2/s, 35.23 - 36.66 mg KOH/g, 16.50 - 20.52 mg/100g and 16.13 - 26.02 mg/kg, respectively) for both regions as compared to the standard values (3.5 - 5.0 mm2/s, 2 mg KOH/g, <5 mg/100g and <10 mg/kg, respectively) of biodiesel for diesel engine. Such properties are very important for engine fuels and if not considered well, may affect engine performance negatively. Therefore adequate treatment of the oil by degumming, etherification and transesterification before use in a diesel engine could avert this difficulty.展开更多
This study was intended to understand how smallholder farmers’modifications improved agroforestry technologies’usability in Uganda’s Mt.Elgon region.We used a case study approach to understand how smallholder farm...This study was intended to understand how smallholder farmers’modifications improved agroforestry technologies’usability in Uganda’s Mt.Elgon region.We used a case study approach to understand how smallholder farmers’contextual realities informed their modifications and enhanced the usability of agroforestry technologies.Data was collected over four months of frequent and regular interaction with the cases using formal and informal methods that included in-depth interviews,conversations,discussions,and direct observations.Emerging themes and patterns were identified from the comprehensively reduced data.In addition,respondents’direct quotes were used to emphasize the reasons for the modifications.The findings showed that smallholder farmers modified the recommended technologies to suit their biophysical and socio-economic realities.Differences and similarities in modifications existed among cases across the agroforestry technologies.The modifications were mainly done to diversify tree uses,optimize space utilization,and minimize production costs for farming households.These findings imply a need to critically examine the smallholder farmers’modifications to make agroforestry technologies applicable and compliant to their contexts.This will inform the re-invention of technologies that will quickly diffuse into the community for broader impact.Findings also emphasize the need to rethink the linear model of technology transfer mainly applied in agroforestry technology development and dissemination because it offers limited space for the much-needed feedback from smallholder farmers.展开更多
文摘Jatropha curcas Linn has been identified worldwide as one of the sources of biodiesel. Biodiesel has energy properties close to fossil diesel and can be a potential energy alternative. However, these properties may vary based on soils, plant genetics and agro-climatic conditions in a given geographical location. Several studies on biodiesel production under such conditions have been done elsewhere, but few have been done on J. curcas oil in Uganda. This study analysed the physicochemical properties of J. curcas L. oil for biodiesel production in Nebbi and Mukono districts using American Standards and Testing Methods (ASTM D6751) and European Standards (EN 14214). J. curcas seed kernel contained 51% w/w and 48% w/w of oil with high levels of Free Fatty Acids (1.52% and 1.93%) and acid values (35 and 36 mg KOH/g) for Nebbi and Mukono, respectively;the difference was significant (p ≤ 0.05). Generally, the quality and quantity of the oil from Nebbi were better than those of Mukono, based on the biodiesel standard values. Nevertheless, kinematic viscosity, acidity, potassium and phosphorus content values were found abnormally high (31.46 - 33.23 mm2/s, 35.23 - 36.66 mg KOH/g, 16.50 - 20.52 mg/100g and 16.13 - 26.02 mg/kg, respectively) for both regions as compared to the standard values (3.5 - 5.0 mm2/s, 2 mg KOH/g, <5 mg/100g and <10 mg/kg, respectively) of biodiesel for diesel engine. Such properties are very important for engine fuels and if not considered well, may affect engine performance negatively. Therefore adequate treatment of the oil by degumming, etherification and transesterification before use in a diesel engine could avert this difficulty.
基金the German Academic Exchange Service(DAAD),ICRAF and NARO for funding this research。
文摘This study was intended to understand how smallholder farmers’modifications improved agroforestry technologies’usability in Uganda’s Mt.Elgon region.We used a case study approach to understand how smallholder farmers’contextual realities informed their modifications and enhanced the usability of agroforestry technologies.Data was collected over four months of frequent and regular interaction with the cases using formal and informal methods that included in-depth interviews,conversations,discussions,and direct observations.Emerging themes and patterns were identified from the comprehensively reduced data.In addition,respondents’direct quotes were used to emphasize the reasons for the modifications.The findings showed that smallholder farmers modified the recommended technologies to suit their biophysical and socio-economic realities.Differences and similarities in modifications existed among cases across the agroforestry technologies.The modifications were mainly done to diversify tree uses,optimize space utilization,and minimize production costs for farming households.These findings imply a need to critically examine the smallholder farmers’modifications to make agroforestry technologies applicable and compliant to their contexts.This will inform the re-invention of technologies that will quickly diffuse into the community for broader impact.Findings also emphasize the need to rethink the linear model of technology transfer mainly applied in agroforestry technology development and dissemination because it offers limited space for the much-needed feedback from smallholder farmers.
