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All Journal Jurnal Ilmiah Teknologi dan Rekayasa Journal of Engineering and Management in Industrial System Jurnal Mechanical Indonesian Journal of Engineering and Technology (INAJET) Journal of Infrastructural in Civil Engineering (JICE) Journal of Sustainable Infrastructure Journal of Emerging Science and Engineering
Yawas, Danjuma S.
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Automotive Engineering Civil Engineering, Building, Construction & Architecture Computer Science & IT Electrical & Electronics Engineering Engineering Environmental Science Industrial & Manufacturing Engineering Materials Science & Nanotechnology Mechanical Engineering

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Development and Characterization of Advanced Recycled Hybrid Metal Matrix Composites via Enhanced Stir Squeeze Casting Method for Industrial Applications Unegbu, Hyginus Chidiebere Onyekachi; Yawas, Danjuma S.
JURNAL MECHANICAL Vol 15 No 2 (2024): JURNAL MECHANICAL
Publisher : Fakultas Teknik, Universitas Lampung

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.23960/mech.v15i2.5267

Abstract

This study presents the development and characterization of advanced recycled hybrid metal matrix composites (HMMCs) using an optimized stir squeeze casting technique. The hybrid composites were fabricated using recycled aluminum alloy (AA6061), ceramic particles, and carbon fibers. The optimization of critical process parameters such as stirring speed, casting temperature, and squeeze pressure resulted in composites with superior mechanical and physical properties. Comprehensive testing revealed that the HMMCs exhibited a 20% increase in tensile strength, a 30% improvement in hardness, and a 15% enhancement in impact resistance compared to conventional metal matrix composites (MMCs). Additionally, the composites demonstrated a 10% improvement in thermal conductivity, making them suitable for applications requiring efficient heat dissipation. The successful incorporation of recycled materials not only promoted sustainability but also reduced production costs. The findings underscore the potential of these hybrid composites for high-performance applications in automotive, aerospace, and thermal management industries. Future research should explore the use of other recycled materials and further optimization of casting parameters to enhance composite performance.
Innovative Energy-Efficient Solutions for Sustainable Development in Nigeria's Construction Industry Unegbu, Hyginus Chidiebere Onyekachi; Yawas, Danjuma S.; Dan-asabe, Bashar; Alabi, Abdulmumin Akoredeley
JURNAL MECHANICAL Vol 15 No 2 (2024): JURNAL MECHANICAL
Publisher : Fakultas Teknik, Universitas Lampung

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.23960/mech.v15i2.5268

Abstract

The construction industry in Nigeria, like many developing countries, faces significant challenges and opportunities in adopting energy-efficient technologies. This study provides a comprehensive analysis of the current state of energy-efficient technologies in Nigeria's construction sector, examining adoption rates, perceived barriers, benefits, and recommendations for enhancing energy efficiency. Data were collected from 50 survey respondents and 15 in-depth interviews with key stakeholders, including architects, engineers, policymakers, and construction managers. The findings reveal that solar panels, LED lighting, and energy-efficient HVAC systems are the most commonly adopted technologies. Regression analysis indicates that regulatory support and stakeholder awareness are significant predictors of technology adoption, while financial constraints, regulatory challenges, and a lack of technical expertise are primary barriers. The thematic analysis highlights the interplay between economic incentives, regulatory environments, and cultural attitudes in influencing adoption. Operational cost savings, enhanced environmental sustainability, and improved indoor environmental quality are identified as major benefits of adopting energy-efficient technologies. The study provides several recommendations, including strengthening regulatory frameworks, providing financial incentives, enhancing capacity-building programs, conducting public awareness campaigns, and improving supply chains for green materials. This research contributes to the understanding of sustainable construction practices in Nigeria and offers practical strategies for overcoming barriers to the adoption of energy-efficient technologies. The findings have important implications for policymakers, industry stakeholders, and researchers aiming to promote sustainability in the construction sector.
Investigating Environmental Degradation of Banana-Sisal Epoxy Composites: Physical and Thermal Properties Unegbu, Hyginus Chidiebere Onyekachi; YAWAS, Danjuma S.; Dan-asabe, Bashar; Alabi, Abdulmumin Akoredeley
JURNAL MECHANICAL Vol 16 No 1 (2025): JURNAL MECHANICAL
Publisher : Fakultas Teknik, Universitas Lampung

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.23960/mech.v16i1.5500

Abstract

This study evaluates the environmental degradation of banana-sisal epoxy composites, focusing on their physical and thermal properties after exposure to moisture, ultraviolet (UV) radiation, and thermal aging. Alkali-treated and untreated composites were fabricated and tested for moisture absorption, tensile strength, flexural strength, thermogravimetric stability, and UV resistance. Results indicate that alkali-treated composites absorbed significantly less moisture (1.26%) than untreated composites (2.62%) after 120 hours of water immersion. Treated composites retained 87.6% of their initial tensile strength and 92% of their flexural strength, demonstrating superior mechanical performance compared to untreated composites. Thermogravimetric analysis (TGA) showed higher onset degradation temperatures (Tonset = 275°C) for treated composites compared to untreated composites (Tonset = 255°C) and better residual mass retention at 600°C. Differential scanning calorimetry (DSC) revealed a higher glass transition temperature (Tg = 93°C) for treated composites, indicating improved thermal stability. After 100 hours of UV exposure, treated composites retained 82% of their tensile strength, compared to 68% for untreated composites. These findings demonstrate that alkali-treated banana-sisal epoxy composites possess enhanced resistance to environmental degradation, making them viable for use in construction, automotive, and marine industries. Future research should aim to optimize fiber treatments, develop hybrid and nanocomposites, and conduct long-term durability and sustainability assessments.
Sustainable Concrete Solutions: Advancing Low-Carbon Infrastructure with Fly Ash in Nigeria’s Construction Industry Unegbu, Hyginus; Yawas, Danjuma S.
Journal of Sustainable Infrastructure Vol. 4 No. 2 (2025): Sustainable Infrastructure Breakthroughs: From Concrete to Circularity
Publisher : Fakultas Perencanaan Infrastruktur, Universitas Pertamina

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.61078/jsi.v4i2.43

Abstract

The urgent environmental challenges posed by the high carbon footprint of ordinary Portland cement (OPC) demand sustainable alternatives in the construction industry. This study aims to evaluate the mechanical performance, durability, environmental impact, and economic feasibility of fly ash-based concrete as a partial replacement for OPC in Nigeria’s construction sector. Concrete mixtures with 20%, 40%, and 60% fly ash replacement were prepared and tested for compressive strength, workability, chloride penetration resistance, sulfate resistance, and water absorption. Advanced life cycle assessment (LCA) and economic analyses were conducted to quantify environmental benefits and cost savings. Results indicate that early-stage compressive strength decreases with increasing fly ash content due to slower pozzolanic reactions; however, significant strength gains occur at later curing stages, with 90-day compressive strengths reaching up to 42 MPa for 40% fly ash mixtures. Durability improvements were demonstrated by a 50% reduction in chloride permeability and a decrease in sulfate-induced mass loss from 0.7% to 0.2% at 60% fly ash replacement. The LCA revealed a reduction in CO₂ emissions by up to 51%, while economic analysis showed cost savings of up to 20% compared to conventional OPC concrete. These findings confirm that fly ash-based concrete provide enhanced durability and substantial environmental and financial advantages, making it a viable, sustainable alternative for construction in Nigeria. However, challenges such as supply chain constraints, quality control, and limited industry awareness must be addressed to enable widespread adoption. Future research should focus on improving fly ash reactivity, exploring hybrid supplementary cementitious materials, and conducting long-term field performance studies to further optimize and validate fly ash concrete applications under local climatic conditions.
Technology and Innovation Management for Circular Economy in Nigeria’s Renewable Energy Sector Unegbu, Hyginus; Yawas, Danjuma S.
Journal of Sustainable Infrastructure Vol. 4 No. 2 (2025): Sustainable Infrastructure Breakthroughs: From Concrete to Circularity
Publisher : Fakultas Perencanaan Infrastruktur, Universitas Pertamina

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.61078/jsi.v4i2.44

Abstract

This research explores the role of technology and innovation management in facilitating the adoption of Circular Economy (CE) principles within Nigeria’s renewable energy sector. As Nigeria strives to address its energy deficit through renewable energy technologies, the integration of CE practices remains limited, especially in terms of resource efficiency, waste reduction, and material recycling. Using a mixed-methods approach, including semi-structured interviews with key stakeholders and a survey of renewable energy firms, this study assesses the extent of technology adoption and Circular Economy integration. The results indicate that solar photovoltaics (PV) and biomass are the most widely adopted technologies, with 80% of firms using solar PV. However, advanced Circular Economy practices, such as waste-to-energy and material regeneration, have been adopted by only 40% of firms. The research identifies several key barriers to the adoption of Circular Economy practices, including technological limitations, high initial costs, lack of government support, and low awareness. The findings underscore the pivotal role of innovation management in overcoming these barriers, particularly through the adoption of advanced technologies like solar PV and energy storage systems. The study concludes by offering policy recommendations, including the need for financial incentives, investment in research and development, and fostering collaborative innovation. These measures are essential for accelerating the adoption of Circular Economy principles, ensuring the sustainability and growth of Nigeria’s renewable energy sector.
Co-Authors A.A., Alabi Alabi, A.A. Alabi, Abdulmumin Akoredeley B., Dan-asabe Dan-asabe, B Dan-asabe, Bashar Unegbu, Hyginus Unegbu, Hyginus C.O. Unegbu, Hyginus Chidiebere Onyekachi