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.
Low carbon steel of 0.12 wt.% C steel cold drawn in 20, 25, 40, and 55% deformations of cold-drawn wires are characterised by brittle fracture when subjected to impact load because the process induces strain hardening. Experiments had been used extensively in industry to find the suitable heat treatment parameters for improved properties. The 0.12 wt.% C steel was heated to the region of austenite and hold for 30 minutes and 40 minutes for comparison, then rapidly cooled SAE 10W-40 engine oil followed by tempering at 400 deg. C. The yield strength of the drawn 25%, 40% and 55% steel reduce. The tensile strength reduces drastically for all the degree of cold-drawn steel. This was as a result of the dissolution of the steel carbon contents into the ferrite phase when heated above the AC1 temperature range and the tendency of the grain to grow due to prolong heating above recrystallisation temperature range. The impact toughness of the samples improves for the treated steel at 30 minutes duration of tempering reduces below the impact toughness of the non-treated steel for treatment at 40 minutes tempering duration for all the cold drawn steel. The toughness is also found to reduce with increasing cold drawn deformation and reduction rate tends to reduce with increasing cold-drawing. This procedure of heat treatment is extensively used for improving the toughness and hardness of the carbon steel. The study demonstrated the possibility of predicting the tensile and yield strength of 0.12 %wt. C steel. The correlation relationship established that the interdependence of the strength and the hardness is more reliable at low tempering duration of 30 minutes compared with the duration at 40 minutes
Coronavirus has shocked the world and almost bought the education sector to a stop. The Nigerian government declared a compulsory lockdown on all states of the federal. The Lagos State Government's passion for education consulted Envivo Education, a private company, to develop an Iclass Learning Management System (ILMS) for virtual teaching. This platform was effective in teaching courses, but the peculiarity of engineering is the basic to understand engineering mathematics the bedrock of all concepts. A Motivated Strategies for Learning Questionnaires (MLSQ) survey was administered to all students who took the engineering mathematics courses. The data was collected, and the statistical analysis was done with Minitab. It found out that the ILMS is good for teaching courses, but to understand engineering courses screenwriting and feedback from students should be included.
— This report is based on a numerical analysis of a three-dimensional analysis of diamond-hole cooling channels in laminar forced convection of a solid body experiencing heat on one side. A diamond hole configuration was studied with different aspect ratios that give a minimum peak temperature at every point in the structure. The solid body volume is fixed and the channel aspect ratio is allowed to change in this direction. The solid body experiences heat flux ( ) on one side and the coolant is allowed to enter into the channels from the opposite side at a given Reynolds number ( ) such that 100 ≤ ≤ 500, and channel aspect ratio ( ) from 1 to 4. The results show that as the and increase, the maximum temperature and thermal resistance ( ) decrease while the Nusselt number increases. Also, the and increase, friction factor decreases and increases, respectively. Comparatively, for a given range of 100 ≤ ≤ 500, and channel aspect ratio ( ) from 1 to 4, about 4%-12% and 37%-44% reduction in the maximum wall temperature and thermal resistance respectively, were reported, while about 55.6%-75% and 50%-68% improvement in Nusselt number and pumping power respectively, were observed. The results establish that heat transfer is improved in the diamond hole channel at various Re and AR. Also, the results reveal that the Colburn j-factor decreases when rises and the aspect ratio decreases due to the heat transfer characteristic increases. Again, pumping power increase rapidly as and increase, which causes a higher pressure drop across the channel and leads to higher energy consumption.
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