Browsing by Author "Onuoha, Chukwudike"

Now showing 1 - 3 of 3
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    Implementation of experimental design in evaluating the mechanical properties of ceramic composites
    (Worldwide Open Access Publisher, 2022) Asotah, Wisdom; Onuoha, Chukwudike; Medupin, Olawale; Elakhame, Zeberu
    The influence of independent variables (firing temperature and residue content) on mechanical properties – hardness, compressive strength, flexural strength, compression modulus and energy at the break – of ceramic composites was investigated through experimental design. Microstructural evaluation using scanning electron microscopy (SEM) and mineralogical identification using x-ray diffraction (XRD) was also accomplished to understand the structure-property relationship. In analysing the observed data, variance analysis was employed to determine the statistical significance of the factors on the responses and regression equations showing correlations were developed. The observed data were shown to accept the null hypothesis for hardness, compression modulus and compressive strength, while flexural strength and energy at break rejected the null hypothesis judging by the p-value. The flexural strength showed a good correlation, but the influence of firing temperature and residue was minimal. However, both factors' square was shown to influence the flexural strength considerably. The study presents a systematic way to understand causal relationships, ensuring that product specifications and quality are met.
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    Modeling the mechanical properties of clay powder filled recycled low density polyethylene composites
    (Scientific Research Publishing, 2020-07-31) Onyedika, Gerald Okwuchi; Onuegbu, Genevive Chinyere; Onuoha, Chukwudike
    This study modeled some mechanical properties of clay powder filled recycled low-density polyethylene, rLDPE (rLDPE composite). The rLDPE is commonly referred to as used sachet water bags. The clay powder (filler) was obtained by sun-drying, grinding, and sieving. Two particle sizes of clay powder were used: −90 µm and −425 µm to represent the passing sizes at different clay powder contents of 5, 10, 15 and 20 wt% which were thoroughly mixed with the recycled low-density polyethylene in an injection molding machine at 173˚C. The results showed that the tensile strength, tensile modulus, hardness, flexural strength, fatigue strength and hardness increased with increase in clay powder contents. However, there were decreases in strain-at-breakage and shear strength as clay powder content increased. Model equations showed that smaller particle size enhanced the mechanical properties and equations generated can be used to predict the properties of composites at predetermined clay contents. Standard deviations obtained for the various mechanical properties show that the model, in most cases had the lowest degree of scatter (dispersion) than those of −90 µm and −425 µm. Hence, these models are suitable to predict outcomes of the properties of the clay filled recycled low-density polyethylene composites
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    Tribological behaviour of periwinkle shell powder-filled recycled polypropylene composites
    (SciPress, 2019) Onuoha, Chukwudike
    Polymer composites are increasingly replacing metals in structures such as gears, wheels, clutches, housings, bushings and other areas where tribology is of great importance. Various ways are used to improve the tribological behaviour of neat polymers, and the most familiar method is the incorporation of fibres/fillers in the polymer to produce composites. In this present research, the tribological behaviour of periwinkle shell powder-filled recycled polypropylene composite was studied. Injection moulding was used for the preparation of the composites and the impact strength, wear resistance and fatigue strength were examined. SEM was utilized to support the discussion of the results. The results showed that the incorporation of periwinkle shell powder into polypropylene improved the wear resistance and fatigue strength but showed no improvement in impact strength