No abstract

Biomass from agriculture is a promising alternative fuel due to its carbon-neutral feature. However, raw biomass does not have properties required for its direct utilization for energy generation. Torrefaction is considered as a pretreatment method to improve the properties of biomass for energy applications. This study was aimed at investigating the effects of torrefaction temperature and residence time on some physical and chemical properties of torrefied corncobs. Therefore, a fixed-bed torrefaction reactor was developed and used in the torrefaction of corncobs. The torrefaction process parameters investigated were the torrefaction temperature (200, 240, and 280 °C) and the residence time (30, 60, and 90 min). The effects of these parameters on the mass loss, grindability, chemical composition, and calorific value of biomass were investigated. It was shown that the mass loss increased with increasing torrefaction temperature and residence time. The grinding throughput of the biomass was improved by increasing both the torrefaction temperature and the residence time. Torrefaction at higher temperatures and longer residence times had greater effects on the reduction in particle size of the milled corncobs. The calorific value was highest at a torrefaction temperature of 280 °C and a residence time of 90 min. The energy yield for all treatments ranged between 92.8 and 99.2%. The results obtained in this study could be useful in the operation and design of torrefaction reactors. They also provided insight into parameters to be investigated for optimization of the torrefaction reactor.

Foundry practice have existed in Nigeria for centuries. However, for the development of the practice, know-how and skills must be developed. Personnel must be trained at all levels. In this study, the practices in foundries of research and academic institutions involved in foundry within Lagos state were investigated. Investigations were carried out by on-site study of the foundries and also by means of questionnaires investigating various aspects of foundry practice. From responses obtained, it was shown that the capacity of foundries to produce technically sound castings is very low. Simple steps capable of increasing the quality and reproducibility of the castings were suggested. It was concluded that students’ learning and local foundry practice can be enhanced by upgrading foundries in research and educational institutions to current global best practices.

In this study, the numerical analysis of conjugate heat transfer of laminar flow in a functionally graded hollow cylinder (FGHC) made of metal/ceramic for a two-dimensional fluid and wall conduction subject to Newton boundary condition is considered. The fluid How to cite this article: Fadipe OL, Adelaja AO, Olakoyejo OT. Transient solution of temperature field of conjugate laminar forced convection heat transfer in functionally graded hollow cylinder.