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A computational model for the heat generation and dissipation in a disk brake during braking and the following release period has been formulated. The model simulates the braking action by investigating the thermal behaviour occurring on the disc and pad surfaces during this period. A comparative study was made between grey cast iron (GCI), asbestos, Aluminium metal matrix composite (AMC), and aramid as brake pad and disc materials. The braking process and following release period were simulated for four material combinations, GCI disc and Asbestos pad, GCI disc and Aramid pad, AMC disc and Asbestos pad, AMC disc and Aramid pad using COMSOL Multiphysics software. The results show similarity in thermal behaviour at the contact surface for the asbestos and aramid brake pad materials with a temperature difference of 1.8 K after 10 seconds. For the brake disc materials, the thermal behaviour was close, with the highest temperature difference being 9.6 K. The GCI had a peak temperature of 489 K at 1.2 seconds and AMC was 465.5 K but cooling to 406.4 K at 10 seconds, while the GCI was 394.7 K.

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This study evaluates the performance and emission characteristics of an orange peel biodiesel blended with cashew nut shell liquid. It investigates the efficacy of cashew nut shell liquid in reducing nitrogen oxide (NOX) emissions resulting from the combustion of the biodiesel, while optimizing its performance.The biodiesel was prepared via transesterification. It was obtained by reacting orange peel oil produced through Soxhlet extraction with methanol in the presence of NaOH. The biodiesel was blended with cashew nut shell liquid in the ratio 70%:30% (B70).Experimental results demonstrate that blending cashew nut shell liquid with orange peel biodiesel causes a slight decrease in NOX emission. B70 generates 150 ppm of NOX, while B100 and diesel produce 159 ppm and 193 ppm, respectively. The hydrocarbon emission of B70 was 8% lower than that of B100 and 22.3% lower than that of diesel. As regards CO and CO2 emission, B70 performs better than B100 and diesel. The performance parameters were computed at brake powers of 2.5 kW, 5.0 kW, 7.5 kW, and 10 kW. In comparison to diesel and B100, B70 has higher brake thermal efficiency at all loads. The brake specific fuel consumption (BSFC) of B70 is higher than that of diesel, but less than that of B100 at 2.5 kW and 5.0 kW. At 7.5 kW and 10 kW, the BSFC of B70 is higher than that of B100 and diesel. Conclusively, B70 gives optimal performance and less emission. Hence, cashew nut shell liquid is a good additive.

This paper discusses the results of studies conducted on raw biogas produced from a prototypic biogas production plant located at the Teaching and Research Farm, University of Ibadan, Ibadan. This setup consists of a mixing chamber, a biogas digester and a stabilizing unit, locally designed and fabricated. It further discusses preliminary and detailed design coupled with the construction of an effective and efficient technology used in purifying raw biogas generated from the prototypic biogas production plant; this technology is otherwise known as the Water Scrubbing technology. The Scrubbing system consists of the Water scrubber with iron wool packed bed connected to a 500 litre water tank, and two tyre tubes which were used in storing the pre scrubbed (raw) biogas and the scrubbed (purified) biogas. The water scrubber has an inlet for the entry of the raw biogas and a discharge for the exit of the scrubbed biogas. Raw biogas from the plant was stored in a tyre tube and directly fed into the Water scrubber housing the iron wool packed bed, the purified biogas from the exit was also collected into another tyre tube. The samples of the gas mixture were taken before and after scrubbing and analyzed with Pascal Manometric Glass Tube technique. Results indicated that methane content of the scrubbed/ purified biogas was raised from 58% to 82% due to the reduction of Carbon dioxide and Hydrogen Sulphide. CO 2 was reduced from 31% to 14% while H 2 S was reduced from 1% to 0.4%.The corresponding Energy content of the purified biogas was evaluated to be 41MJ/kg which is higher than that of the raw biogas which was evaluated to be 29MJ/kg. Design and Construction of a Water Scrubber for the Upgrading of BiogasTemilola T Olugasa* and Oluwafemi A Oyesile Department of Mechanical Engineering, University of Ibadan, Ibadan, Nigeria enrichment in rural areas, and characteristic as a universal solvent. In addition to these, the packing material in the scrubbing setup increases the contact time between the biogas and water. This work is therefore aimed at providing an effective and efficient scrubbing technique that would be capable of removing significant amounts of Carbon dioxide and Hydrogen sulphide, resulting to an increase in the energy content of biogas and the recommendation of the commercial use of purified biogas in Nigeria [3][4][5][6][7][8][9][10]. Materials and Methods Assessment and selection of a biogas plantThe biogas plant at the Teaching and Research Farm, University of Ibadan was selected as the case study. This biogas plant has a biodigester of 2 m 3 capacities, a mixing chamber and a stabilizing unit. 8 kg of Cow dung was transported from the dairy farm, University of Ibadan to the location of the biogas plant at the Teaching and Research Farm. The system was charged with cow dung at the ratio of 1:1 (water to cow dung) and left in an open area with ambient daily average temperature of 31.5 o C and monitored for a period of 14 days. After proper mixing in the mixing chamber, the system was left air-ti...