Asymmetric supercapacitor based on novel coal fly ash derived metal–organic frameworks as positive electrode and its derived carbon as negative electrode

Journal of Applied Electrochemistry - The paper presents a comparative study between aluminum fumarate metal–organic framework (Al-FumMOF) and a novel coal fly ash derived aluminum MOF...     

Willingness to pay for the services of commercial motorcycles in Akure, Nigeria

Most planning solutions aimed at redressing public transport problems in Nigeria continue to fail, because they are ad hoc and do not take into consideration the willingness to pay for improved transport facilities and services. This paper examines some factors that affect the willingness of citizens to pay for the commercial motorcycle (locally called okada) services in Akure. The okada is a new mode regarded to have contributed to improved transport in the city. The paper presents some determinants and estimates of the willingness to pay for this transport mode. Empirical analysis shows that the incident of armed robbery by operators and the education of citizens are the significant factors affecting citizen's willingness to pay. Other important factors include the method of determination of trip fares, variations in weather conditions and stability of trip fares. Some policy implications of the findings are discussed.     

Antioxidant properties of chlorophyll-enriched and chlorophyll-depleted polyphenolic fractions from leaves of Vernonia amygdalina and Gongronema latifolium

This study investigated the optimum polyphenol extraction conditions for two Nigerian green leafy vegetables, Vernonia amygdalina (VA) and Gongronema latifolium (GL) that are widely used for food and medicinal purposes. Seven different solvents were used to extract the total phenolic contents of the leaves; 100% acetone, 80% acetone, 50% acetone, 100% ethanol, 70% ethanol, 100% methanol and 70% methanol and their total phenolic contents were determined. The results showed that the 80% acetone was significantly (p < 0.05) the most effective for polyphenol extraction from the leaves and generally the acetone-containing solvents were more effective than alcohol-containing solvents. The 80% acetone extract was fractionated on a silicic acid-packed column to give two main fractions: acetone eluted chlorophyll-enriched (flow-through) and ethanol eluted chlorophyll-depleted (column-bound). The ethanol fractions of VA and GL were significantly better (p < 0.05) DPPH radical scavengers than the acetone fractions. In contrast, the acetone fraction was a significantly better (p < 0.05) scavenger of hydroxyl radicals when compared to the ethanol fraction. Both acetone and ethanol fractions significantly (p < 0.05) and dose-dependently inhibited linoleic acid oxidation, though duration of inhibition was less at lower concentrations (10 and 25 ??g/ml) than at the highest concentration (50 ??g/ml).