Afe Babalola University Based Journals
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Investigation of Flexural Strength of African Copalwood (Daniella Oliveri) as Reinforcement in Concrete Slab
No full textThis study investigates the potential of African Copalwood as a reinforcing material in concrete slabs. The timber rods were randomly selected from the timber market because there is always variation in timber properties with position in stem, location and soil condition. Various test specimen were prepared according to the Code of practices BS EN 408:2003 using structural size specimens. Thirty (30) slabs of size 75 mm x 300 mm x 700 mm were cast in five sets (1 to 4%) for Timber-reinforced concrete slab (TRCS) and Steel-reinforced slab (SRS) with a mix ratio of 0.5:1:2:4 denoting water-cement ratio, cement, fine and coarse aggregate respectively. Longitudinal bars were varied in 1% to 4% slab cross-sectional area in different TRCS samples while the transverse bar was restricted to be 3% by standard and made constant in all the slab samples specimen. A 10 mm diameter steel bar is used as reinforcement in the SRS. Findings revealed that the mean failure stress for Tensile strength parallel to grain was 41.80 N/mm2, Bending strength parallel to grain was 37.05 N/mm2, Compression parallel to grain was 13.48 N/mm2, Compression perpendicular to grain was 8.88 N/mm2, Local Modulus of Elasticity (MOE) was 3800.17 N/mm2, Apparent MOE was 59.42 N/mm2. Also, with regards to TRCS, the flexural strength test at 28 days for 1% to 4% reinforcement in concrete slabs is 3.61, 5.29, 5.49 and 7.22 N/mm2 respectively. The SRS has a flexural strength of 11.54 N/mm2 at 87.5% composition in slabs. These findings indicate enhancement in the strength properties of the concrete slabs with the incorporation of the African Copalwood reinforcement
Whale Optimization Technique Based Economic Load Dispatch
No full textThis study concentrates on optimizing the Economic Load Dispatch (ELD) for three major Nigerian power systems: Sapele, Jebba, and Egbin. These systems, each comprising varying numbers of generating units and facing fluctuating load demands ranging from 300 MW to 1000 MW, necessitate efficient resource allocation to minimize operational expenses. Employing the innovative Whale Optimization Algorithm (WOA), inspired by the cooperative behaviour of humpback whales, this research tackles the intricate non-linear characteristics of the ELD problem. The primary goal is to determine the ideal power generation timetable that reduces total generation costs while fulfilling power demand constraints. Through mathematical modelling, the power systems and their economic aspects are represented. The proposed WOA-based approach is implemented and juxtaposed against optimization methods to gauge its efficacy in achieving cost-effective load dispatch. In addition to the fast convergence characteristics of the optimization technique, the study reveals minimum optimal generation costs of 150,567 Naira/Hr, 189,352 Naira/Hr, and 244,075 Naira/Hr for the Sapele, Jebba, and Egbin power systems, respectively, under various load conditions. Conversely, maximum optimal generation costs reach 480,431 Naira/Hr, 590,871 Naira/Hr, and 750,453 Naira/Hr for the same systems, demonstrating the algorithm's adaptability to diverse load scenarios
Investigation of the Fitness for Service (FFS) of Cracks in API 5L X70 Pipeline Steel using Failure Assessment Diagram (FAD)
Get PDFIn this study, the fitness for service of crack propagation in API 5L X-70 stee1 was investigated using a model called Failure Assessment Diagram (FAD) to determine how fit a crack can be under certain operational pressure. It is a known fact that during the production of pipes, there are tendencies for flaws such as inclusions and cracks to occur in the pipes. When these flaws are subjected to stresses, there are tendencies for failures to occur starting from where the cracks or flaws are located. The failure due to the propagation of the cracks leads to oil spillage causing pollution to the environment which had negatively impacted livelihood of the host communities and aquatic lives. This had resulted in Government spending huge amount of money maintaining the pipelines and remediation. The purpose of this paper is to investigate the fitness for service of crack lengths 12 mm, 17 mm, 22 mm and 27 mm using the Failure Assessment Diagram (FAD) mode1. The material used in this paper is API 5L X 70 steel in the form of a Compact Tension (CT) specimen machined according to ASTM E1820 – 13. API 5L X-70 stee1 is a low-carbon stee1 with a carbon content of as low as 0.04 %. It is used in the production of pipelines for conveying crude oil and natural gas from the place of production to the place of refining or export. In the investigation of the fitness for service of the cracks, a charpy V-notch impact test was carried out to determine the energy required to fracture the steel, which was later inputted numerically into a critical stress intensity factor formula in accordance with BS 7910 – 13 standards to obtain the critical stress intensity factor (KIC or KQ). The stress intensity factor (KI) was obtained from formula also according to BS 7910 – 13 standards. The ratio of KI to KQ was used in the FAD analysis. Subsequently, a monotonic tensile test was conducted to obtain the yield stress ( ys) and the reference stress ( ref) was obtained numerically according to BS 7910 – 13. The ratio of ref) to ys) was also used in the FAD analysis. The FAD analysis was used to determine the fitness for services and fracture behaviour of each crack. Scanning electron microscopy (SEM) was used to confirm the fracture behaviour obtained from the FAD. The results obtained show that the energy from the charpy V-notch impact test was 302.9 J and the critical stress intensity factor (KQ) correlated numerically according to BS 7910 – 13 was determine as 246.73 MPa . The yield stresses obtained from the monotonic test for crack lengths of 12 mm, 17 mm, 22 mm and 27 mm were 132.51 MPa, 109.10 MPa, 114.36 MPa and 118.21 MPa, respectively. In the FAD analysis, it was observed that the safe operational stress to ensure fitness for service decreases with an increase in crack length. The fracture behaviour shows a ductile fracture behaviour since the FAD lies within the plastic collapse region. This fracture behaviour was confirmed by the image obtained from the scanning electron microscopy (SEM), which showed a cup and cone image suggesting ductile fracture behaviour. This FAD method will ensure that safe operational stresses are maintained for various crack length to prolong the life span of the pipeline. It is a novel method that can also be used to properly schedule the rate of inspection in pipelines alongside Ultrasonic sound, Liquid penetrant, Magnetic particle and radiographic methods of inspection
Microstructure Characteristics and Mechanical Properties of Grey Cast Iron at Varied Ferrosilicon Addition
Get PDFInoculation is an essential metallurgical route for controlling solidification conditions of cast iron, consequently, in this study, the influence of varied percent ferrosilicon (FeSi) addition on microstructure and mechanical properties of grey cast iron (GCI) was investigated. A 50Kg capacity rotary furnace was used to melt the charge (Auto engine block scrap, graphite, ferrosilicon (FeSi) and limestone). The casting was produced in a greensand mold with wooden rectangular pattern of length 50 mm and breadth 30 mm. Chemical compositions and carbon equivalent values (CEVs) of the samples were determined, using Optical emission spectrometry (AR 4 metal analyzer) and the expression respectively. Microstructures of the samples were obtained, using metallurgical microscope (model number NJF-120A). The tensile and hardness properties were measured, using Universal tensile tester and Rockwell hardness tester respectively. From the results, C and Si were the major elements. Other trace elements were Mn, P, S and Al. CEVs of both the control and inoculated samples were less than 4.3%. Microstructure of the control sample was comprised of primary dendrites and graphite flakes, while those of the inoculated samples were characterized by varied amount of more developed primary dendrites, longer graphite flakes and austenite dendrites. Also, a number of small MnS particles were observed in relative amount within the microstructures. Tensile and hardness properties of the FeSi inoculated samples were superior to the control sample. Highest tensile strength and hardness values of 76.62 MPa and 99.89 HRB respectively were obtained at the optimum inoculation of 1.5 wt. % FeSi
Characterization of Rice Husk for Graphene Extraction and Metallization
Get PDFRice husk, an underutilized agricultural waste product, serves as a potential precursor for graphene synthesis. This study focuses on synthesizing and characterizing graphene through the chemical exfoliation method, employing advanced analytical techniques to explore its potential applications in metallization. Graphene was produced by chemically activating rice husk ash (RHA) with potassium hydroxide (KOH) at 800 ºC. The extracted graphene underwent analysis using various techniques. X-ray Diffraction (XRD) confirmed the material's crystalline nature and graphitic structure. Fourier-Transform Infrared Spectroscopy (FTIR) identified typical functional groups present in the synthesized graphene. Raman Spectroscopy revealed significant defects and confirmed that the graphene consists of single or few-layer thin sheets. Transmission Electron Microscopy (TEM) showed the presence of thin graphene sheets and nanoparticles with sizes ranging from 1.47 nm to 5.80 nm. Ultraviolet-Visible Spectroscopy (UV-Vis) confirmed electronic structure and optical properties, essential for metallization. X-ray Fluorescence (XRF) confirmed the purity of the graphene, while Brunauer-Emmett-Teller (BET) analysis revealed a high specific surface area, making the material suitable for surface-based applications. Electrical conductivity tests demonstrated good conductivity in the lower to moderate current range. The study underscores the potential of rice husk-derived graphene for metallization, offering a cost-effective and eco-friendly synthesis method for industrial and commercial applications
Narratives of Resistance: Discursive Strategies in Nigeria’s 2020 #EndSARS Protest
Get PDFThe #EndSARS hashtag, which started in 2017, was one of the tools used to share, on Twitter, experiences and advocacy on police brutality in Nigeria. Extant works have explored the use of social media for civic engagement, consciousness re-awakening, counter-narratives and societal disruption, amongst other uses. The present study focuses on how discursive strategies of resistance were deployed to create and sustain agitations using Twitter as a mobilising force of mass movement to achieve political goals. van Dijk’s socio-cognitive model of Critical Discourse Analysis (CDA) with insights from computer-assisted textual analysis was used to analyse a corpus of 1,000 tweets with the #EndSARS hashtag. Findings show that blame attribution, recontexualisation of events, categorisation, victim positioning, and cross-border appeal are discursive resistance strategies used to sustain solidarity, create bonds and negotiate power among the marginalised people. Through these, protesters were able to create defiance and directive acts in the people. These strategies not only create a contest for political power between the government and the masses but also help in the construction of a resistance ideology among the people. Hence, new perspectives on social media should consider the paradigm shift that has resulted in how narratives are sustained and negotiated during online social movements
Russia-Ukraine War and Implications of Finland’s Membership of NATO
Get PDFThis study examines how the war between Russia and Ukraine has tilted Finland into the orbit of NATO. Therefore, the research approach is a qualitative systematic literature review, and it examines scholarly papers, foreign policy reports, and websites like Carnegie Europe and the Atlantic Council that deal with international relations. In addition, the study examines what this milestone poses for East-West relations within the international system going-forward. The study as a concluding remark indicated that the war between Russia and Ukraine has significant geo-political ramifications which are discussed in this study. Likewise, Ukraine's struggles on the battlefields are still raging, while neighbouring nations like Finland and Sweden have sought stronger ties with both of them making connections with NATO for increased security in response to the crisis. Similarly, the defection of Finland into the NATO alliance is of consequential impact on global dynamics. As a result, insightful information on the changing dynamics of the area and the difficulties of post-conflict international cooperation and security are gleaned from the comprehensive literature research
The Interface Between Metaphysics and Science
Get PDFThe interface between metaphysics and science refers to the close-knit relationship between Metaphysics as First Philosophy and science. The first conception of metaphysics by Aristotle makes its appearance after Physics. The issue at hand borders on the lacuna between metaphysics and science, on the first hand, and on the interconnectedness of the metaphysics, and by extension the whole of philosophy, and the sciences of Physics, Chemistry, Biology and Engineering. We must underscore the view that Metaphysics investigates into the ground and foundation of all regularities and irregularities in nature. It is the first philosophy and the first science. We shall, therefore, probe into the development of modern science from classical antiquity and state the mistake of rejecting metaphysics by the logical positivists as a fundamental injury to science. Our attempt to recover and rediscover the metaphysical foundations of science shall reestablish an enabling interface between metaphysics and science. Our discussion shall first be on metaphysics as the first philosophy and the first science. After examining how science has dovetailed from metaphysics, we would reestablish the interface between metaphysics and science
Faces and Phases of Leadership: A Metaphoric Interpretation of Olusegun Obasanjo’s My Watch
Get PDFThis paper explores the deployment of conceptual metaphors in the memoir of former president Olusegun Obasanjo, examining how metaphorical affordances shape expressions and their purported meanings. Through a discourse analysis of the memoir, My Watch, the research shows how metaphors drawn from the second volume of the memoir create vivid description of the faces and phases of leadership through the author’s lens. The study relies on George Lakoff and Mark Johnson’s Conceptual Metaphor Theory. The paper discusses the faces and phases of leadership in volume two of former president Olusegun Obasanjo’s My Watch and explores the concepts of leadership. Seventeen excerpts are purposively selected and analysed based on their relevance to the discourse. Findings reveal that metaphors uncover servitude, reformation, fight, bliss, constant learning, healing and accomplishment inherent in leadership. All these show that the phases and faces of leadership are laced with changing conditions, internal demands, and outside influences. This study, therefore, posits that metaphors are engaged to show inherent semantics, and convey other messages to the reader. The findings of the research point to the role of the metaphors to better comprehend political memoirs and more importantly the intricacies of leadership.
 
Nigeria’s Amalgamation, Social (In)Justice and Security Implications
Get PDFNigeria emerged in 1914 after the colonialists amalgamated the southern and northern protectorates for administrative purposes without negotiation of the conditions of amity between peoples of both sides. However, with independence from British rule on 1st October 1960, come some challenges arising from glueing together peoples with divergent cultures, languages, historical antecedents and religions. Some of these problems have metamorphosed over time to generate serious security issues. Taking into consideration Nigeria’s political history, this paper examines the implications of the welding of diverse peoples with different orientations for Nigeria’s unity, peace and security. The core position of the paper is that amalgamation was accompanied by some inevitable social injustice that arose as a result of coercing unequals together; the consequence is that social injustice in the Nigerian state bred insecurity. This is so because Nigeria, as a result of the amalgamation, was made to become a deeply divided society. This is responsible for entrenching deep fault lines which have engendered violence and thus threatened security in Nigeria. The methodology employed for the study is qualitative in nature and involves critical content analysis of texts, library and archival materials