http://repository.aust.edu.ng/xmlui/handle/123456789/354 This collection contains the theses of Materials Science and Engineering Students from 2012-2022 2026-06-08T11:18:26Z http://repository.aust.edu.ng/xmlui/handle/123456789/5204 Development and Characterization of Bio-Based Basalt Fiber Reinforced Polymer Composites for Automotive Structural Applications Musa, Abdulrahman Adeiza The growing demand for sustainable lightweight materials in the automotive industry has increased interest in basalt fiber-reinforced polymer (BFRP) composites as eco-friendly alternatives to conventional composites. Basalt fibers (BFs) offer excellent mechanical properties, thermal stability, and environmental benefits. However, their application is often limited by weak interfacial bonding with polymer matrices due to their smooth and chemically inert surfaces. This study presents a novel nanocellulose (NC) grafting approach as the primary contribution, where cellulose nanofiber (CNF) and cellulose nanocrystal (CNC) were directly anchored onto silane-functionalized BFs before composite fabrication. Unlike conventional direct NC dispersion in epoxy, which often suffers from agglomeration and poor dispersion, the proposed grafting strategy localizes NC at the fiber–matrix interface, significantly improving load transfer and interfacial adhesion. The NC-grafted BFRP composites exhibited significant improvements in interfacial bonding, resulting in enhanced impact resistance, interlaminar shear strength, and overall mechanical performance compared with composites produced through direct NC–epoxy mixing. In addition, the grafted composites demonstrated improved resistance to moisture absorption, despite the naturally hydrophilic nature of NCs, indicating that surface immobilization of NC effectively mitigates water uptake at the interface. Surface analyses using X-ray Photoelectron Spectroscopy (XPS) and Field Emission Scanning Electron Microscopy (FE-SEM) confirmed successful grafting and improved interfacial morphology. To assess structural applicability, composite components were further evaluated through impact crushing experiments and finite element simulations using Abaqus CAE. The strong agreement between experimental and simulation results confirmed the reliability, energy absorption capability, and crashworthiness of the developed composites for lightweight automotive structures. Overall, this work demonstrates that NC grafting onto BFs is a highly effective strategy for overcoming interfacial bonding and dispersion challenges, offering a promising route toward durable and sustainable automotive composite materials. 2026-04-23T00:00:00Z http://repository.aust.edu.ng/xmlui/handle/123456789/5160 Mechanical Biomarkers and LHRH/EphA2-Molecular Biomarkers: A Theragnostic Approach for Triple Negative Breast Cancer Diagnosis/Treatment Ezenwafor, Theresa Chikwuo The adhesive interactions between molecular recognition units (such as specific peptides and antibodies) and antigens or other receptors on the surfaces of tumours are of great value in the design of targeted nanoparticles and drugs for the detection and treatment of specific cancers. In addition, the heterogeneous nature of cancer and difficult challenges in early detection has activated a high interest in the development of mechanical biomarkers for cancer diagnosis. This current study presented Luteinizing Hormone Releasing Hormone (LHRH) and Epherin type A2 (EphA2) as a promising biomarker to design a targeted therapy for diagnosis and treatment. Furthermore, the work provides insights through atomic force microscope (AFM) and Nanoindentation (NI) on the application of adhesion forces, adhesion energy, viscosity and statistical deconvolution as diagnostic tools to detect TNBC as well as to characterize it into different histological grades. To appraise these discoveries, TNBC tissue samples of different histological grades were selected (non-neoplastic or Grade 0) and (neoplastic of Grade I to Grade III). To evaluate the receptor overexpression, and their distributions on the human breast tissue extracts, using Immunohistochemistry (IHC) technique, as well as the actin cytoskeletal structures of non tumorigenic and tumorigenic breast tissues (grade I to grade III), a combination of immunofluorescence and confocal microscopy, and atomic force microscopy was used. The adhesion forces between LHRH or EphA2 and human TNBC breast tissues are measured using force microscopy techniques that account for the potential effects of capillary forces due to the presence of water vapor. A combination of nanoindentation and statistical techniques is then used to measure the deformations/viscoelastic properties of non-tumorigenic and human TNBC of different histological grades. The investigation of the underlying magnitude of antigen – antibody interactions corresponding to adhesion energy are also determined using adhesion contact theories/models. A Standard Fluid Model/Anti-Zener Model II is also used to characterize the viscoelastic properties of the non-tumorigenic and tumorigenic TNBC tissues of different grades. The results show that the pull off forces and adhesion energies associated with higher grades of TNBC are shown to be greater than those associated with normal/non-tumorigenic human breast tissues, which were studied as controls. The observed increase in adhesion forces and adhesion energies are also correlated with the increasing incidence of LHRH/EphA2 receptors at higher grades of TNBC. Moreover, the decrease in the viscoelastic properties as well as the actin cytoskeletal structural density observed to be connected to the TNBC tissue histological higher grade are lower than those of non-neoplastic breast tissues. The implications of the results are discussed for the development of targeted nanostructures for the detection and treatment of TNBC, also the potential application of nanoindentation and statistical deconvolution techniques to the development of mechanical biomarkers for TNBC detection /cancer diagnosis. Main Thesis 2023-02-05T00:00:00Z http://repository.aust.edu.ng/xmlui/handle/123456789/5159 Valorization of Underutilized Lignocellulosic Biomass Wastes for Biofuel Production Uzoagba, Chidiebele Ejikeme The study focuses on utilizing lignocellulose biomass (LCB) as a sustainable feedstock for biofuel production to address fossil fuel depletion, climate change, energy poverty, and environmental issues in Africa. With global energy demand rising and agriculture generating significant waste, the study explores agricultural residues and unconventional biomass sources, such as Prosopis africana, for bioenergy generation. Africa faces severe energy poverty, with millions lacking access to electricity and clean cooking facilities. The research aims to assess the energy potential of these residues and promote circular economy principles through bioenergy production. Methodologically, the study used data from the FAOSTAT database to analyze various crop residues for their suitability in bioenergy generation. It employed empirical analysis and modeling techniques to assess energy potential. For Prosopis africana, proximate, ultimate, and compositional analyses were performed using advanced techniques like scanning electron microscopy, X-Ray diffraction, and thermogravimetric analysis to determine the biomass’s physical, thermal, and chemical properties. Additionally, the hybrid composition of Prosopis africana pod and cowpea husk was evaluated for briquette production, optimizing particle size, binder concentration, and densification pressure using Response Surface Methodology. Results indicate that agricultural residues hold significant potential for bioenergy, supporting sustainable resource utilization and promoting circular economy practices. Prosopis africana exhibited high heating values (15.23 to 20.49 MJ/kg), positioning it as a strong candidate for biofuel production. Optimal briquette properties were achieved with specific particle size, binder concentration, and densification pressure, improving mechanical and combustion characteristics. The study concludes that agricultural residues and Prosopis africana can alleviate Africa’s energy challenges, promote environmental sustainability, and contribute to economic development. The findings offer critical insights into scaling bioenergy production and adopting circular economy principles. Further investigations are ongoing to address socio-economic challenges related to bioenergy adoption. Main Thesis 2024-11-05T00:00:00Z http://repository.aust.edu.ng/xmlui/handle/123456789/5146 Laser Induced Heating of Polymer Nanocomposites for Hyperthermia in the Treatment of Triple Negative Breast Cancer Onyekanne, Maria Chinyerem Euphemia The work presents the results of an experimental and computational study of the effects of laser-induced heating provided by magnetite polymer-based nanocomposite structures that are being developed for the localized laser-induced hyperthermic treatment of triple-negative breast cancer. Magnetite nanoparticle-reinforced polydimethylsiloxane (PDMS) nanocomposites were fabricated with weight percentages of (1 %, 5 %, and 10 %) magnetite nanoparticles. The fabricated nanocomposites were exposed to incident Near Infrared (NIR) laser beams with well-controlled powers to generate specific elevated temperatures at different times. The mechanical and thermal properties of the different PDMS-based nanocomposites were critically studied. This was because the unique characteristics during the laser-nanocomposite interactions were driven by the both thermal, microstructural, and physicochemical properties (mechanical properties) of the PDMS-based nanocomposites. Under in vitro conditions, our results from the laser-nanocomposites interactions show a decrease in the cell viability of triple-negative breast cancer cells (MDA-MB-231). Using an ex vivo chicken tissue, laser-nanocomposites interactions resulted in well-controlled temperatures in the hyperthermia domain (41 °C and 44°C) in a submillimeter range using a chicken tissue model. Interestingly, laser irradiation and interaction with the nanocomposites did not cause any observed physical damage to the chicken tissue but resulted in significant breast cancer cell dead. The potential in vivo performance of the PDMS nanocomposites was also investigated using computational finite element models of the effects of laser-magnetite nanocomposites interactions on the temperatures and thermal doses experienced by tissues that surround the nanocomposites devices. The outcomes of the experimental studies were validated using the results from the computational analyses. The implications of the results are discussed for the potential design of plasmonic/magnetic-based nanocomposites devices with attractive combinations of mechanical, structural, and thermal properties that are relevant to laser hyperthermia and photo-thermal-ablation for the localized treatment of triple-negative breast cancer tissue. Main Thesis 2022-07-02T00:00:00Z