Search Results (3)

The increasing demand for efficient and sustainable industrial processes has accelerated research into green alternatives. Gas fermentation in a trickle bed reactor is a promising technology; however, optimal scaling up is still challenging. A mass transfer model is crucial for identifying bottlenecks and suggesting design improvements to optimize the scale-up of TBR for gas fermentation. This study explores the effects of temperature, reactor dimensions, and packing material size on the volumetric mass transfer coefficient (k_La) in a commercial-scale trickle bed reactor (TBR). Using dynamic mass transfer modeling, the research results highlight that thermophilic conditions (60 °C) significantly enhance k_La and mass transfer rates for H₂, CO, and CO₂, despite reduced gas solubility at higher temperatures. Additionally, packing material of smaller particles improves k_La by increasing the surface for gas–liquid interaction, while reactor dimensions, particularly volume and diameter, are shown to critically influence k_La. This study provides valuable insights into optimizing TBR design and scale-up, emphasizing the importance of thermophilic conditions, proper packing material selection, and reactor geometry for efficient gas–liquid mass transfer in syngas (a mixture of H₂, CO, and CO₂) biological conversion. Overall, the findings offer practical guidelines for enhancing the performance of industrial-scale TBR systems. Full article

Social networks and social groups are often regarded as being important elements of social capital. The research set out in this paper is designed to explore whether social groups in villages located close to the Nigerian capital city of Abuja seek to lever benefits from the connections (networks) they may have with the government and others in that city. Of special interest is whether there is a significant difference between secular and faith-based social groups in terms of the leveraging of such support. The research builds upon a previous study that employed a questionnaire-based survey of 26 social groups spanning two area councils (ACs; Bwari and Kwali) in the Federal Capital Territory of Nigeria followed by a series of in-depth interviews with leaders of the groups (e.g., chairperson, secretary, and treasurer) to explore the findings. The results were analysed using regression and suggest that most groups (14) had sought to lever support from their connections in Abuja. Those more likely to leverage support were registered with their respective ACls, a requirement for accessing credit from formal lenders, and tended to be smaller in size in terms of membership. There was also some suggestion that leverage was more likely with male social groups than female ones. Registration with an AC was more likely for secular groups than religious ones. Religious-based groups in the villages did not see their activities as being ‘project orientated’ and instead regarded their role as being in community support. Social groups cannot be thought of as static and exclusive and the diversity of such groups at the village scale is a source of strength for their communities. The results have important ramifications for those institutions, especially faith-based ones, wishing to work with social groups to help in the design and implementation of development initiatives. Full article

For various reasons, leaves are occasionally lyophilized prior to storage at −80 °C and preparing extracts. Soluble carbohydrate identity and quantity from maize leaf disks were ascertained in two separate years using anion exchange HPLC with pulsed electrochemical detection. Analyses were made from disks after freezing in liquid nitrogen with or without subsequent lyophilization (both years) or directly after removal from plants with or without lyophilization (only in the second year). By adding the lyophilizing step, galactose content consistently increased and, frequently, so did galactoglycerols. The source of the galactose increase with the added lyophilizing step was not due to metabolizing raffinose, as the raffinose synthase (rafs) null mutant leaves, which do not make that trisaccharide, also had a similar increase in galactose content with lyophilization. Apparently, the ester linkages attaching free fatty acids to galactoglycerolipids of the chloroplast are particularly sensitive to cleavage during lyophilization, resulting in increases in galactoglycerols. Regardless of the galactose source, a systematic error is introduced for carbohydrate (and, most likely, also chloroplast mono- or digalactosyldiacylglycerol) amounts when maize leaf samples are lyophilized prior to extraction. The recognition of lyophilization as a source of galactose increase provides a cautionary note for investigators of soluble carbohydrates. Full article