Anaerobic Digestion and Co-digestion of Poultry Droppings (PD) and Cassava Peels (CP): Comparative Study of Optimal Biogas Production

An investigation of the effects of poultry droppings (PD) on the anaerobic co-digestion of cassava peels (CP) has been conducted in order to determine the kinetics for optimal biogas production. The laboratory batch anaerobic digestion were carried out in five (5) different ten-litre anaerobic digesters which were used for the fermentation of the substrates with cumulative biogas production of 13.1, 24.6, 16.7, 8.6 and 7.1L/g volatile solid(VS). The digesters A, B, C, D and E with process conditions of (100% PD and 0% CP), (75% PD and 25% CP), (50% PD and 50% CP), (25% PD and 75% CP) and (0% PD and 100% CP) respectively, were incubated for forty four (44) days at ambient mesophilic temperature of 37±1 oC at a pH of 6.7. The gas production did not begin until the second day for the first four digesters while that of digester E started on the fourth day, (this is as a result of high cellulose content) and then increased steadily until it reached a maximum biogas yield between the 18 th and 22nd day of anaerobic digestion. The highest biogas production of 24.6L/g volatile solid(VS) recorded in digester B could be attributed to better synergy of microorganisms in the digester as a result of the presence of some limited quantity of cassava peels and a C/N ratio of 23.4. This result shows that biogas production could be enhanced effectively through co-digestion process of substrates.. Keywords: Anaerobic, Biogas, Co-digestion, Feedstock, Mesophili

Software for Stresses and Mohr’s Circle Computation, Transformation and Sensitivity Analysis

Software has been developed for stress and Mohr’s circle computation, transformation and sensitivity analysis. It is developed to help students visualize the state of stress at a point and to understand the nature and effects of stress transformation which is one of the leading importance phenomena in the field of engineering. The software shows the effect of stresses on materials inclined at different angles and subjected to axial compressive loading. The software is developed in java programming language, because it is simple, objectoriented and user friendly. The developed software calculates normal stress, tangential stress, resultant stress as well as obliquity of resultant stress with changing orientation while Mohr circle is used to support the graphics. It also shows the behaviour of stresses on materials as the angle of inclination varies. Keywords — Stress, Software, Stress transformation, Mohr’s Circle, Principal stress, Tangential stress, Resultant Stress, Obliquity of resultant Stres

Comparative study of the optimal ratio of biogas production from various organic wastes and weeds for digester/restarted digester

This study carried out a comparative analysis of the rates of production of biogas fromvarious organic wastes and weeds which enabled the determination of optimal ratio of poultrydroppings to domestic wastes. Digester was prepared for the anaerobic fermentation of the domes-tic wastes and weeds. The gas production did not begin until the 7th day and increased steadily atfirst, and then increased sharply until it reached its peak on the 18th day before declining. The totalgas produced within the 22 days of experimentation was 1771 cm3. The maximum volume of gasamounting to 809 cm3was produced by the sample containing 50% poultry dropping and 50%weeds. This indicates that this sample possesses the best C/N ratio of all the samples prepared.For restarted digester, gas production began on the 2nd day as against the 7th day with no restarteddigester and the gas production peaked earlier

Thermal Analysis of Solar Box Cooker in Omu-Aran Metropolis

Just like other solar cookers, the solar box cooker needs energy gotten from the sun to operate without producing emissions. In this research, a solar box is fabricated to reduce over-dependence on fossil fuel for energy generation. This reduces the environmental degradation caused by the use of other sources of energy. The ASHRAE empirical model was used to obtain the solar irradiance present in Omu-Aran metropolis. Thereafter, the no-load and load test was conducted to determine the cooker’s thermal performance. The tests were conducted between January 2018 and January 2019 in Landmark University, Omu-Aran, Kwara State, Nigeria with geographical coordinates 8° 8' 0" North, 5° 6' 0" East. The average energy and exergy efficiency of the cooker were 32oC and 28oC respectively. A decrease in the efficiency of the cooker was observed. This was because the reflector, which is made from aluminium foil, was degrading. As a result of this degradation caused the sun rays (radiation) to be reflected poorly into the absorber and also caused a myth of overcast sky. Meanwhile, the variation in solar radiation during the sensible heating test resulted in the fluctuation inefficiency. The ratio of water to absorber temperature which was above 0.80 during the pre-boiling heating process indicates that the cooker can be recommended for sterilization