Browsing by Author "Obiukwu, O. O."

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    Bioethanol production from the fermentation of casava waste
    (U. P., 2012-02) Obiukwu, O. O.; Garba, B.; Gaji, M. M.
    This experiment has been carried out with the singular aim of converting the cassava waste to ethanol. To achieve this, the conversion of the organic waste was carried out via acid and microbial hydrolysis which yielded 66% fermentable sugar wort. This was then converted into ethanol by fermentation process using Saccharomyces cerevisae. 98% ethanol was obtained by distillation of the fermentable wort and the total volume of the ethanol produced from 105grams of cassava waste was 103.4ml. Fermentation logistic parameters where evaluated considering the percentage fermentable sugar yield from the biomass in study. It is more economical to produce ethanol from organic waste compared to gasoline from crude oil for vehicle engines. The total volume of ethanol produced was used to verify the optimization and room temperature was considered to be the optimum temperature for the fermentation of ethanol from cassava waste. 120 minutes offermentation time gave 96.76% production yield.
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    Corrosion inhibition of mild steel using plant extract (Vernonia Amygdalina (Bitter Leaf) and Azadirachta Indica (Dogoyaro)
    (U. P., 2012-02) Obiukwu, O. O.; Ignatius, O.; Oyinna, B. C.; Osuagwu, C. M.; Ogbuo, T. E.
    The corrosion inhibition of mild steel, coated with Vernonia amygdalina (Bitter Leaf) and Azadirachta indica (Dogoyaro) and immersed in hydrochloric acid (HCl) solution, tetraoxosulphate (IV) acid (H2SO4) solution, trioxonitrate (v) acid (HNO3) solution, distilled water, sea water and exposed to the atmosphere, was investigated in a laboratory scale experiment. The concentration of the acids used was 2.5M for each acid. The weight loss method, corrosion rate and inhibitive efficiency was used to carry out the experiment, at intervals of four (4) hours for twenty-four (24) hours for the acid test and seven (7) days interval for a period of fourty-two (42) days for the other test with sea water, distilled water and exposure to the atmosphere and the results were obtained and recorded accordingly. The results obtained showed that the Vernonia amygdalina (Bitter leaf) and Azadirachta indica have inhibitive efficiencies of 91% and 69% respectively in acid solutions . Azadirachta indica proved to be a better inhibitor at the early stage of immersion in HCl with efficiency of 43% and was the best inhibitor in H2SO4 with an efficiency of 91% at the early stage of immersion in the acid. The test on HNO3 was not successful due to corrosive nature of the acid even when the concentration was reduced.
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    The effect of surface finish on the low cycle fatigue of medium carbon steel
    (Federal University of Technology, Owerri, 2024-10) Obiukwu, O. O.; Nwafor, O. M. I.; Okafor, B.; Osueke, G.
    As fatigue cracks initiate predominantly at the free surface of a material, the condition of the surface can be assumed to be critical with regards to fatigue strength. The features of a mechanically prepared surface which are considered to be major factors affecting fatigue strength fatigue are stress concentration (a shape factor), dimension (a scale factor), and surface finish (a technological factor). This paper investigates the effect of surface finish on the fatigue life of AISI/ SAE 1040 (medium carbon steels). A compositional analysis was performed to ascertain the percentage of carbon in the materials. The specimens were machined to a precise gauge length and diameter and exposed to various surface finishes mainly; polishing and grinding machining surface conditions. A fatigue test was performed with the use of Avery Dennison and bending stress was obtained using the curve supplied with the machine. The results from the machine were converted to Mega Pascal (MPa) and the values used to plot S-N curves. The fatigue resistance for the specimens at various surface finishes of the different carbon steels was thus established. The results show that the polished surface with surface roughness (Ra = 0.20microns) has the longest fatigue life.
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    The optimum mesophilic temperature of batch process biogas production from animal-based wastes
    (Federal University of Technology, Owerri, 2010-05) Obiukwu, O. O.; Nwafor, O. M. I.
    The optimum temperature of biogas production from blends of animal-based wastes was determined under controlled heat supply to the digester in a batch digestion process. Cow Dung (CD) and Poultry Droppings (PD) were blended in the ratio of CD: PD::1:3. The digester was operated at average ambient temperature of 30°C as baseline. Biogas production from the waste blends was monitored under the temperatures of 32°C to 45°C. Results obtained indicate maximum cumulative gas yield was observed at the temperature of 40°C.The 40°C temperature gave the highest biogas yield of 2685 ml followed by the 35°C temperature with the cumulative yield of 2535 ml. The ambient temperature of 30°C had the least cumulative biogas yield of 185 ml. These results indicate that increased and steady biogas production can be achieved under the optimum mesophilic temperature of 40°C when these animal-based wastes are digested in batch digestion process.