Nigerian Journal of Technology

Editorial

Chidozie C. Nnaji — 2024-10-25

No Abstract

Effects of substitution of cement with ground granulated slag on concrete produced with different water-cement ratios

S.I. Adedokun — 2024-10-25

Due to growing concerns on the need for alternative material to partially replace cement considering the high cost and environmental problems associated with its production, this study investigated the impacts of fractionalsubstitution of cement with ground granulated steel slag (GGSS) onthefeatures of concrete produced by varying water-cement ratios (w/c). Cement was replaced with GGSS at 0, 10, 20, 30, 40, and 50%. The binder, sandandgranite ratio of 1:2:4 as well as the w/c of 0.3, 0.4, 0.5, 0.6, and 0.7wereused.The X-ray fluorescence (XRF) analyser was utilized to ascertain the chemical composition of the GGSS, and its result revealed that GGSS is aclass FPozzolan. The fresh and hardened concretes containing various levelsofreplacement of cement with GGSS under varying w/c were subjected to workability and various strength tests. Response Surface Method(RSM) was employed for optimum condition analysis that maximized the results of the Compressive Strength (CS), Split Tensile Strength (STS) and Flexural Strength(FS) tests. Findings revealed that concrete becomes more workable with increasing w/c, but declined as the substitution of cement with GGSS increased. The strengths of the concrete declined with increasing w/c; however, the addition of GGSS improved its strength’s properties. The optimized 21.57%GGSS substitution for cement with w/c of 0.45 gave maximum value of 25.95N/mm²for CS, 4.24 N/mm² for STS and 5.74 N/mm²for FS. The comparative cost analysis between the conventional concrete and the optimized OPC-GGSS concrete shows that as much as 11.2% of the concrete constituents’ cost canbesaved if GGSS is used to substitute OPC in the concrete production. Theoptimized concrete, which can be utilized as reinforced concrete withimprovedstrength and reduced cost, is therefore recommended for use with the target CSof 25 N/ mm².

Assessment of fire damage in concrete structures: A comprehensive study using colorization and non-destructive testing

M. Kumar — 2024-10-25

The research paper investigates the impact of fire on concrete structures, focusing on evaluating the temperatures reached during the fire using the colorimetry test method. It examines color changes as indicators of temperature, assesses the extent of damage to building components, and determines the depth of carbon penetration within the structure. The study employs various assessment techniques, including rebound hammer test, colorimetry test to evaluate structural integrity post-fire. Key findings include the correlation between color changes and temperature, the effectiveness of rebound hammer tests in assessing structural integrity, and the importance of considering aggregate type in color analysis. The study was conducted using prescribed nondestructive testing (NDT) techniques. For the investigation of the fire-damaged building, the Rebound number (RN) values were used to correlate the in-situ compressive strength of concrete using the standard curves developed in the laboratory for this purpose. Moreover, the approximate temperature to which any structural element had reached was determined approximately by colorimetry test. Further the residual compressive strength of concrete of these elements was also derived applying the reduction factors in Eurocode 2 for concrete exposed to varied temperatures. The maximum percentage difference between these two sets of values was 15.46% except for one case. The residual strength values of concrete of the structural elements paved a way for satisfactory evaluation of the need of retrofitting of these elements, Overall, the research offers practical insights for assessing the residual compressive strength of concrete of structural elements of fire-damaged concrete structures by two different techniques thus aiding in decision-making for rehabilitation or reconstruction efforts of such structures.

Variational formulations of vibration equations of sinusoidal shear deformable beams and Eigenfrequency solutions by finite sine transform method

C. Ike — 2024-10-25

This study presents analytical solutions using the finite sine transformation methodology (FSTM) for the natural dynamic solutions of thick beams. The Euler-Bernoulli beam theory (EBBT) disregards the contributions of transverse shear strains due to the Euler-Bernoulli- Navier orthogonality hypothesis used in its formulation and is unsuitable for thick beams. It derived a variational formulation of flexural vibration equations of sinusoidal shear deformable beams using first principles approach. The governing equation is formulated for transverse dynamic loading and in-plane compressive force as a nonhomogeneous partial differential equation (PDE). The PDE did not need shear correction factors. The formulation yielded a cosine function shaped transverse shear strain and stress distribution which was maximum at the neutral axis and vanished at the beam surfaces. The PDE was solved for free flexural vibration where it became homogeneous due to the absence of forcing excitation forces. The FSTM was used for solving simply supported beams since sinusoidal kernel complies with end conditions. The problem simplifies for harmonic excitation to an algebraic eigenvalue problem solvable using algebraic methods. The roots are utilized to compute modal vibrations and the resonant vibration frequency at the first mode, (n = 1). The resonant frequencies obtained are identical with past results that used theory of elasticity technique. The results for the first five vibration modes are also close to previous results obtained thick beam models for all modes and aspect ratios considered. The effectiveness of the FSTM and its accuracy has been demonstrated for simply supported thick beam vibration problems.

Comparative effects of selected wastes on the indices and strength properties of laterite soil

S.I. Adedokun — 2024-10-25

This study carried out comparative analyses of the potentials of induction furnace slag (IFS), rice husk ash (RHA) and saw dust Ash (SDA) on the geotechnical properties of the A-7-6 and CL classified laterite soil obtained from Imota, Lagos State. By these classifications, the laterite soil is a poor subgrade material that requires stabilization before it could be utilized for engineering applications. Moreover, IFS, RHA and SDA are agro-industrial waste materials, whose poor disposal systems pose serious concerns to the environment. As one of the sustainable ways of reusing these wastes, the laterite soil was treated with 0-10% of these wastes by mass of the soil sample. The impacts of these admixtures on the grain size distribution, specific gravity, Atterberg limits, compaction, uniaxial compressive strength (UCS) and California bearing ratio (CBR) were determined based on relevant standard procedures. The study revealed that the percentage of specimen passing 0.075 mm sieve increased with increase in admixture contents. However, the specific gravity of the soil decreased with the addition of RHA and SDA but increased significantly with IFS treatment. The plasticity index of the stabilized samples reduced with increasing IFS content, while it increased with RHA and SDA additions. UCS values increased from 108.90 kPa for the natural soil to 150.90 kPa, 146.57kPa and 121.52 kPa at 10% addition of IFS, RHA, and at 8% SDA, respectively. The CBR increased from 63.38% for the natural soil to 157.19%, 98.98% and 88.94%, and from 9.12% to 38.59%, 24.74% and 14.13%, for IFS, RHA, and SDA, respectively under unsoaked and soaked conditions, respectively at 10% stabilization. The research findings indicate that IFS have significant impacts on soil properties than RHA and SDA, and the addition of 4% IFS makes this soil a suitable material for both subgrade and sub-base road courses.

Development and application of concrete sensor to measure onsite strength of concrete

I.O. Olofintuyi — 2024-10-25

According to sustainable development goals 13 which emphasized on Infrastructure, Innovation and Industry. Innovation through creation and development of device is important in order for developing countries like Nigeria to attain her self-realization in industrialization. In this paper, a concrete sensor called “ConSor” was developed to measure onsite strength of concrete using the principle of maturity described in ASTM C-1074. The materials used are DB1386 thermocouple, arduino board having wireless modules and components to enable seamless and wireless communication of data to the web. The device was programmed using C++ to read temperature (heat data) generated from the concrete and convert it using the maturity function (equation) to maturity. The maturity was thereafter converted to strength through calibration from crushed laboratory samples of same mix. The results obtained from the developed device was compared with industryestablished concrete sensors (Commandcenter sensor and Hilti concrete sensor) and laboratory samples using appropriate standards of concrete testing. The results obtained at each curing ages for the Consor was closer in accuracy of ±0.05N/mm² to the industry- established concrete sensors for strength and ±0.5℃ and for temperature readings. This is a clear indication that the developed device has capacity and suitability to be deployed for onsite strength of concrete.

A hybrid best worst - fuzzy topsis methodology for lean Six Sigma project selection

O.F. Odeyinka — 2024-10-25

Prioritizing Lean Six Sigma (LSS) projects that align with company objectives is crucial, yet traditional methods struggle with associated subjective criteria. This study proposed a hybrid Best Worst Method - Fuzzy TOPSIS approach to prioritize LSS projects for a project consulting company. The method integrates expert opinion from 3 decision-makers on 7 main criteria and 24 sub-criteria to select the optimal LSS projects in project management consulting company. Triangular fuzzy numbers were used to describe the responses. The fuzzy positive and negative solutions of the five alternatives were calculated. Results indicate project alternative 3 (ERP Deployment Project) is the optimal choice with the highest closeness coefficient (0.68651), while project alternative 2 (Warehouse Automation Project - 0.54077), project 1 (Data Warehousing Project – 0.46731), project 4 (Battery life improvement – 0.54077), and project 5 (Improvement of OEE – 0.34093) follow closely, thus ensuring efficient project selection. Emphasis should be placed on project 3 when considering the 7 criteria while the other projects are closely monitored in the ranking order. Future research can explore the combination of other multi- criterion decision making approaches that enrich criteria weights and address the subjectivity of decision-makers’ opinion. The hybrid methodology used in this work is applicable in other disciplines where selection and ranking problems exists.

Proximate property and thermal stability characterization of chemically activated carbon for organic friction lining materials

L.M. Akuwueke — 2024-10-25

This work studied the proximate property and thermal stability of chemically activated carbon developed from agrowaste materials for organic friction linings. The proximate property, degradation steps, optimum degradation temperature (ODT) and oxidative stability (oxidation onset temperature (OOT) and oxidation temperature (OT)) characterizations were performed on two processed samples. Coconut shell activated carbon (CSAC) and palm kernel shell activated carbon (PKSAC) were used to prepared three compositions (%vol.) and particle sizes (µm); 0% CSAC : 100% PKSAC, 50% CSAC : 50% PKSAC, and 100% CSAC : 0% PKSAC and 60, 105 and 150 µm. Thermogravimetric analysis (TGA) and modulated differential scanning calorimetry (MDSC) methods were used to perform the characterizations and results compared with two commercial brakepads (CB1 and CB2) as controls. The proximate analysis showed that 60µm of 0% CSAC : 100% PKSAC had the best results with 6.04% moisture, 3.99% volatile matter, 84.8% fixed carbon and 4.79% ash and compared well with the commercial friction lining materials (CB1: 2.27% moisture, 2.18% volatile matter, 45.47% fixed carbon, 48.86% ash; CB2: 1.92% moisture, 1.49% volatile matter, 37.21% fixed carbon, 58.07% ash). The thermal stability of 0% CSAC : 100% PKSAC, 50% CSAC : 50% PKSAC and 100% CSAC : 0% PKSAC samples with 150µm particle size showed percentage ODT increase of 18.3% and 15.8%; 37.1% and 34.2%; 17.8% and 15.3% when compared with CB1 and CB2 respectively. For all developed activated carbon compositions and particle sizes, the oxidation onset temperature (OOT) compared well with CB2 while oxidation temperature (OT) compared well with CB1. Overall, the developed activated carbon compositions showed suitability for organic friction lining applications.

Mechanical properties of aluminum alloys produced using different stircast stirring rates

O. Adigun — 2024-10-25

In this study, we examined how different stir casting stirring rates affected the mechanical properties of aluminum-copper (Al-Cu) alloys. Al-Cu alloys were cast and developed utilizing an electromechanical stir casting technique with stirring rates ranging from 0-90 revolutions per minute (rpm), and the alloys had Cu compositions of 0–15 wt. % (weight percent). The microstructural evolution was investigated using an advanced optical microscope. When the developed alloy materials were evaluated for microhardness and tensile strength, it was found that the raise in composition of copper and increase in stirring rate led to progressive improvements in microhardness while changes observed with the tensile strength were obviously indeterminate. The mechanisms responsible for the changes seen are also described.

Chemical Vapour Deposition (CVD) and Physical Vapour Deposition (PVD) techniques: Advances in thin film solar cells

A.E. Adeoye — 2024-10-25

Thin film solar cells are gaining popularity as an affordable, efficient, and flexible substitute for traditional silicon solar cells . This success is closely tied to the deposition techniques used to fabricate their layers. This review explores and analyzes the advances in the major deposition techniques for solar cell applications, offering insights into their underlying principles, associated advantages, drawbacks, and suitability for diverse materials and device architectures. The two primary deposition for thin film solar cells are PVD and CVD. In PVC materials are physically ejecting from a target, and depositing it onto a substrate. While, CVD entails the reaction of gases or vapour precursors to creating film on a substrate. The ability to achieve high purity, control over film properties, scalability, and compatibility with flexible substrates are notable advantages. However, challenges such as high costs and complexity can impact the commercial viability of certain techniques. Recent advancements in the technology of thin film deposition for solar cells include the discovery of novel materials with enhanced light absorption and electronic charge transport capabilities, emerging deposition processes such as pulsed laser deposition, and atomic layer deposition scalable and low-cost processes like roll-to-roll processing, and integration with other technologies like perovskite solar cells and tandem devices. Understanding these techniques and staying informed about recent advancements and future directions empowers researchers and engineers to innovate and create improved thin film solar cells, contributing significantly to a more sustainable future through enhanced solar energy harvesting technologies.

Change detection for urban expansion in Baghdad City Al-Doura area using geographic information systems

T.H. Mushtaq — 2024-10-25

The Al-Doura region is undergoing a deterioration in soil quality as a result of the ongoing expansion of residential areas. The expansion is leading to environmental degradation, affecting native plant life and the overall ecosystem. This study employed remote sensing techniques to analyze and comprehend land patterns in the Doura region throughout a defined timeframe, with particular emphasis on the influence of the Doura refinery. The research conducted from 2013 to 2023 was categorized into five distinct areas: urban, water, soil, streets, and plants. This categorization was achieved by utilizing remote sensing data and the ENVI tool. The classification was executed via the support vector machine classifier. The results demonstrate notable changes in the Doura, marked by a swift and substantial growth of the metropolitan region. The expansion has led to a significant reduction in green spaces, with the urban area comprising 21.21% in 2013, rising to 36.71% in 2018, and further increasing to 60.16% in 2023. The categorizations suggest a decrease in the availability of arable land, indicating the expansion of the residential area of Al-Doura. Urban development intensifies land surface temperatures and adds to air pollution. A sustainable approach is necessary to address the presence of the Al-Doura refinery, with a focus on achieving a balance between economic and environmental requirements.

Total spectral efficiency maximization in multi-users cognitive radio networks with energy-harvesting capability

E. Obayiuwana — 2024-10-25

In this paper, the joint radio resource management issues in a cognitive radio network driven by radio frequency energy harvesting (CRN- RF-EH) functionalities are investigated. For the CRN-RF-EH, the cognitive radio (CR) node first harvests its required energy directly from the transmitter of spectrum licensed user for its data communication and consequently transmits its data on the licensed frequency of the legacy user using the underlay accessing technique. Thus, RF-EH is an exciting innovation for energizing low-powered next- generation wireless networks (NGWNs). Consequently, due to CRN-RFEH’d low power limitations, the resource allocation for CRN-RF-EH has to be optimized considering the trade-off among spectral efficiency, energy efficiency, and RF energy supply. Equal allocation of transmission time and/or transmission power may not be efficient for CRN-RF-EH with limited transmission time and power resources. A joint optimal time and power allocation (OTPA) strategy for CRN-RF-EH is proposed to maximise the total spectral efficiency of the CRN- RF-EH. The coupled variables in the formulated joint resource allocation problems create a non-convex optimization problem formulation. For analytical tractability, the non-convex optimization formulation is initially converted to its equivalent standard convex optimization formulation using proper variables and next, it is then solved using the convex optimization technique. The CONOPT solver, a powerful optimization-solving tool for solving convex optimization problems, is utilized to resolve the equivalent standard convex optimization problem formulation. When compared with the baseline biased random time optimum power allocation (BRTOPA) scheme, numerical simulation results show that the OTPA strategy dramatically improves the total spectral efficiency performance. In a severe radio propagation environment with a path loss exponent (PLE) equal to 3.5 such as in urban areas and less severe radio propagation environment with a path loss exponent (PLE) equal to 2.0, such as in rural areas, the OTPA outperformed the BROTPA with a mean performance improvement of approximately 23. 96% and 42.94% , respectively.

A synthetic pid gain tuning framework for robust pitch attitude control of slender airframes

T.A. Fashanu — 2024-10-25

The need to decentralize microsatellite launch missions, as a result of rapid expansion of space technology has led to the emergence of slender (microsatellite) launch vehicles (SLV). However, navigation cost, in terms of onboard equipment, state estimation and control algorithms presently prohibits microsatellite launch vehicle missions. Thus, to realize mission affordability of slender launch vehicles, this work developed a Hardware In the Loop rig for optimizing hardware cost and maximizing the performance of implemented state estimation and control algorithms on slender launch vehicles navigation systems. Apriori, the National Agency for Space Research and Development Agency scaled the characteristics of NASA's Ares I Rocket launcher to obtain a miniaturized slender launch vehicle. This prototype is interfaced with MATLAB’s SIMULIINK environment to build an experimental rig for autopilot simulation to realize affordable navigation systems on slender launch vehicles. In the feedback control loop of the simulated autopilot system, the proportional, integral and derivative control gains of the simulated autopilot were initialized by classical control laws; this seamlessly transits to a smart fuzzy logic based gain selection algorithm within the rise time of the system’s response. This smartly filters nonlinear structural vibration noise from the state estimation system, as well as proactively selects the proportional, integral and derivative gains of the autopilot system. Inference from the flight data sheet established rigorous coupling between structural and control hardware dynamics. Thus, to demonstrate structural interference cancellation, and improve on the autotuning ability of the semi- intelligent pitch attitude control algorithm; a preplanned rocket trajectory of 700m altitude and 15 seconds flight duration was modelled for adaptive tracking such that the desired control objectives are realised. In profile, the realized trajectory indicated that dynamic interaction between rocket structure and control hardware was effectively attenuated. Inflight, the recorded maximum deviation from the referenced trajectory is 0.16% (overshoot). This transient error is mostly due to unmodelled wind induced structural excitation.

A fuel pipeline monitoring and security system using Wireless Sensor Networks (WSN)

O.M. Ezeja — 2024-10-25

Pipeline infrastructure plays a critical role in the transportation of vital resources, including oil, gas, and water. However, pipeline failures and leaks can have devastating consequences, resulting in environmental damage, economic losses, and risk to human life. Traditional methods of leak detection, such as visual inspection and pressure testing, are often time-consuming, laborintensive, and unreliable. With the advent of wireless sensor networks (WSNs), there is an opportunity to revolutionize pipeline monitoring and leak detection. In this paper, we present a system that can monitor and detect leakage early, to enable engineers carry out prompt maintenance. This is made possible by the use of a network of nodes in a WSN, placed along a pipeline, each of which is capable of measuring and reporting varying flow rates, indicative of possible leakages. The system design consists of three major layers namely, the nodes layer, the cloud layer (for data logging), and the reporting layer. Tests were conducted under various conditions. The results show that with no leakages, the average flow rates for nodes 1, 2, 3, and 4 were 16.89747978, 16.89935602, 16.90978163, and 16.93380634 respectively. Furthermore, percentage flow rate differences of -0.02550353, 29.959675, and 30.3944134 were recorded for nodes 2, 3, and 4 respectively, after leakages occurred. The high values of the percentage difference for nodes 3 and 4 indicate a significant discrepancy in flow rate, worthy of physical inspection. The system is capable of detecting faults and leakages, even in the event of sensor failure, or network disruption.

Thermal profiling of a switched reluctance machine with 6/4 pole topology

C.E. Abunike — 2024-10-25

This paper presents a thermal analysis of a switched reluctance machine (SRM) with a 6/4 pole topology. Employing a two-dimensional thermal finite element model in Maxwell 2D integrated into a lumped parameter thermal network in MotorCAD, the research aims to realize critical temperature points within the SRM, focusing on the windings and laminations to identify potential hotspots. To ensure continuous operation without compromising structural integrity, temperature constraints of 150 °C for the windings and 100 °C for the laminations were enforced. The investigation extends to the cooling domain by utilizing a housing cooling jacket and ethylene glycol and water ratio (EGW) of 60/40 as the cooling fluid. An exploration of various volume flow rates revealed that 15 l/min was the optimal choice, resulting in the lowest temperatures observed in both the winding and lamination regions. This study emphasizes the shift of hotspot temperatures from the stator winding in the low-speed region to the rotor in the high-speed range, impacting the overall continuous operating time. This holistic examination significantly contributes to a broader understanding of electric machine thermal management and offers invaluable insights for practical applications in electric vehicles, manufacturing processes, and various industrial settings.

Electromechanical impact of poles on the performance of double stator machine

C.C. Awah — 2024-10-25

The electromechanical effect of rotor pole numbers on machine output parameters such as flux linkage, induced-voltage, torque, power and demagnetization of a double stator permanent magnet machine is presented in this study. The investigation is carried out through the application of MAXWELL-2D finite element software. The study revealed that the machine topology that has 11 rotor poles would have higher flux linkage, inducedelectromotive force, torque and power amplitudes compared with other analyzed machine types. Nevertheless, the machine type that has 14-rotor poles would have the largest output torque, if the machine types are subjected to the same amount of permanent magnet material or volume. Also, the 14-pole machine type has the widest-speed coverage, an excellent quality for traction and vehicle applications. Similarly, the results revealed that the compared machine topologies have good capability against demagnetization effects. The largest shaft torque produced in the 10-pole, 11-pole, 13-pole and 14-pole machine types is 1.37 Nm, 2.44 Nm, 2.28 Nm and 1.47 Nm, respectively.

Toughness of augmented cables for ethernet technology assessment

O. Ogundapo — 2024-10-25

This paper provides a method of assessing the toughness of augmented cables required for Ethernet technology. The use of augmented category 6 (Cat 6A) in Ethernet-enabled Internet of Things (IoT) infrastructure continues to grow due to the high demand for services requiring such configuration. The increasing demand for Cat 6A over Ethernet is due to its ability to transmit both data and power to devices used in IoT which is cost-saving. However, the availability of counterfeit and substandard cables in the market disguised as category-rated cables is of great concern to cable installers and engineers. There is also the basic problem of handling stress anticipated during installation as cables could be manipulated in the form of repeated coiling and uncoiling. Therefore, there is a need to have a method of assessing the toughness of the cables before deployment. In this paper, two Cat 6A cables from different manufacturers were selected from the market to be used as samples for the experiment. The Cat 6A cables were exposed to two rounds of coiling to imitate the handling stress anticipated during installation. The return loss and near-end crosstalk (NEXT) of the cables which are the major performance indicators were collected using the DSX-5000 cable analyzer for each of the test processes. This is to evaluate their resilience or otherwise to handling stress. Feature Selective Validation (FSV) which is a standardized method of measuring the degree of agreement between two data sets was used in this research. The results showed the cable with the lowest variations between the first and third test measurements for each of the pairs examined. The method presented showed that it can be used to assess cable measurements which can lead to objective decisions on the cables selected for deployment.

Energy efficiency analysis of edge IoT Umudigi A9 pro on cross-tier networks: impact of distance and user-friendly applications

E.B. Mfonobong — 2024-10-25

This paper investigated the energy utilisation of edge IoT mobile devices on the 3G and 4G networks, specifically focusing on the impact of the distance from the base station and user-friendly applications. Measurements were taken, and data was collected on a live network during active and passive sessions using enabling software on the test device. The study found that energy consumption varies based on distance, service type, and network usage. With IoT-matched software applications, the Umudigi A9 Pro device showed increased power consumption as distance from the base station increased and as a function of the network utilised. The study also examined video streaming, voice calls, and video playback services, focusing on their energy profiles. The analysis of both real-time and non-real-time services was carried out. Real-time services exhibited an average maximum power consumption of 243.2mW, while non-realtime usage averaged 209.1mW. The internal energy utilisation levels ranged from 370.1mW to 446.9mW for online idle radio operations and from 322.5mW to 458.3mW for offline idle radio operations, varying from the cell centre to the cell edge within a base station sector. It was shown that real-time applications on edge mobile user equipment (UEs) are more energy-intensive than other applications. Their energy requirements increased as these nodes moved towards the cell edge of the network coverage area, possibly due to Signal-toInterference- plus-Noise Ratio (SINR) limitations. Real-time services require more energy than non-real-time services and understanding the relationship between signal strength and test device energy requirements about the service deployed can serve as an advisory tool for energy management.

Integration of geospatial and geophysical data for assessing borehole conditions at the University of Ilorin, North-Central, Nigeria

A.A. Fatoyinbo — 2024-10-25

Even with pre-drilling geophysical surveys, the failure rates and suboptimal productivity of some boreholes within the University of Ilorin (UNILORIN) are a cause for concern. This present study investigated the hydrogeological capability and potentiality of some borehole sites at the university. To achieve this, an inventory of 47 boreholes with an existing lineament density map and Groundwater Potential Zonation (GWPZ) map of Ilorin South Local Government Area were integrated. These boreholes were categorized based on the lineament density, and groundwater potentiality. The results showed that 96% of the sampled boreholes were sited on zones of low groundwater potential (LGWP) while 4% were on zones of moderate groundwater potential (MGWP). Also, 17% of the boreholes coincided with zones of moderate lineament density, 83% of boreholes coincided with zones of low lineament density and no borehole was found to coincide within areas of high lineament density. The findings suggested that 83% of these boreholes (39 units) were drilled due to exigencies (e.g., cost consideration, proximity to facilities etc.) while only 17% of these boreholes (8 units) were drilled on account of scientific necessity or after the appropriate geoscientific evaluation was done. The findings in this study will benefit stakeholders and practitioners in water resource management in building robust models and databases at both regional and local levels.

Geogenic and anthropogenic sources of heavy metals contamination of soils from selected dumpsites in Jos, Plateau State, Nigeria

S.C. Odewumi — 2024-10-25

Heavy metal contamination in Yantrailer, Tina, and Maternity dumpsites soils within Jos was investigated. Twelve samples were collected at two different sampling points at depths of 40 cm and 80cm in each sampling point. The samples were air-dried and subjected to X-ray fluorescence (XRF) analysis to determine their elemental composition. XRF analysis detected the presence of Molybdenum (Mo), Zirconium (Zr), Strontium (Sr), Rubidium (Rb), Uranium (U), Thorium (Th), Lead (Pb), Arsenic (As), Zinc (Zn), Tungsten (W) and Copper (Cu). The higher value of Zr (394.396-499.054 mg/kg) at 80 cm depth than the Zr value (406.581-444.142 mg/kg) at 40 cm from Yantrailer suggests a geogenic contamination source. Higher values of Zr (915.985-935.203mg/kg) at 80 cm depth than its value (663.403-746.535 mg/kg) at 40 cm depth from Tina dumpsite indicates a geogenic contamination source. The higher value of Zr (594.659- 654.508 mg/kg) at 40 cm depth than its value (521.707-565.414 mg/kg) at 80 cm depth from the maternity dumpsite indicates an anthropogenic contamination source. Higher values of Mo, Zr, U, and Th at 80 cm depth than at 40 cm depth from Yantrailer and Tina dumpsites indicate geogenic sources while higher values of Zr, Th, Sr, and Zn at 40 cm depth than at 80 cm depth from maternity dumpsites suggest anthropogenic contamination sources. The higher concentrations of Sr and Zn at 40 cm depth than at 80 cm depth from Yantrailer and Tina dumpsites indicate anthropogenic contamination sources. The soils underlying the dumpsites in the study area have been contaminated with heavy metals from anthropogenic and/or geogenic sources. The anthropogenic sources could be associated with the decomposition of domestic and industrial wastes which have eventually been leached into the underlying soils while geogenic sources of contamination could be associated with weathering and dispersion of heavy metals from underlying mineralization and parent rocks.

Spatiotemporal assessment of wetlands and land reclaim activities in Eastern Lagos State Nigeria

J.A. Oyedepo — 2024-10-25

This paper presents a spatiotemporal assessment of sand-filling practices and their environmental implications in eastern Lagos over a four-decade period (1984-2024). Multispectral Landsat TM images at ten-year intervals namely, 1984, 1994, 2004 and 2024 were obtained from the Sentinel hub and subjected to supervised classification to assess land area that was reclaimed over time. The classification revealed a significant shift in land cover categories; areas built-up, expanded from 6035.92 hectares in 1984 to 18002.77 hectares in 2024, while vegetation and water bodies decreased from 19351.48 to 9180.79 and from 29355.12 to 27341.49 hectares respectively. The area occupied by the sand-filled category was 508.85 in 1984, 2528.79 in 1994, 943.19 in 2004, 600.50 in 2014 and 726.95 in 2024. The cumulative area of sand-filled in forty years is 5308.28 hectares. Sand-filled areas were always converted to buildings after some years of consolidation, hence the lack of a particular trend in coverage over time. Sand filling activities are primarily driven by urbanization and infrastructure development, and they are intensified along the eastern coastline of Lagos, particularly from Victoria Island to Lekki. The ecological and environmental consequences of sand filling, include habitat loss, shoreline erosion, increased land surface temperatures (LST) and vegetation loss. The regression coefficients showed that every unit increase in the LST led to a 0.08 unit reduction in the vegetation index for 2004 and 2014, and a one unit rise in the LST led to a 0.1 unit reduction in the vegetation index value for 2024. This paper concludes with emphasis on the key role of remote sensing in monitoring sand-filling dynamics, guiding policy interventions, and promoting sustainable urban growth.

Layout analysis of v-groove solar collector

V. Ogwo — 2024-10-25

This study undertakes the comparative layout study of a V-grooved solar air heater (SAH) with a view to show the optimum design layout for the air heater. Several studies have been conducted on comparing isolated V-groove SAH with other designs of SAH. However, from literature there have not been studies on the comparative layout pattern of V-groove SAHs. It was equally, observed from literature that design layouts of V-groove systems are mainly parallel in nature. Thus, there is a knowledge gap on studies focusing on the layout pattern of Vgrooved systems. Thus, the paper seeks to address this with the research question as “What is the optimum layout for a V- groove solar air heater?” In comparison to active mode of solar air heating, the heat energy analysis of passive solar air heaters, has not been widely studied. Hence, the study is limited to natural convection systems. The study focuses on comparative analysis/evaluation of two basic layout of V-grooved solar air heater- parallel and perpendicular air flow design layouts. The outcome of the work has revealed that the systems can easily be adapted to low temperature applications. From the study, it is deduced that even though the Parallel designed layout of V-groove SAH showed a better efficiency when compared to the Perpendicular designed layout of V-groove SAH that both of them are statistically the same at 5% probanility level using the completely randomized design (CRD) statistical method. The layout pattern does not necessarily mean better output in operation. However when compared to similar works done using the same dimensions for flat plate designs that there is an appreciable improvement in the efficiency of operation.

Water productivity of improved cassava varieties under tropical rain-fed conditions

B. Tayo — 2024-10-25

In most sub-Saharan African countries, cassava propagation occurs through dry farming techniques that involve cultivation without irrigation, which inhibits water management culture. This study investigated the water productivity of enhanced cassava cultivars in tropical rain-fed locations with dry farming conditions. Soil samples were obtained from three locations in the field using a soil auger and sieve analysis. Four enhanced stem cassava varieties free of disease (TMS 30572, TMS 980505, TMS 920326, and TMS 090581) were analyzed for growth characteristics for 90, 120, and 150 days after planting (DAP), and the number of tubers per plant, tuber length, tuber circumference, root depth, above ground biomass, and tuber yield were measured. Agronomic growth metrics, including height of plant, stem diameter, and number of nodes and stems, were also measured. The cassava crop coefficient was obtained and the reference crop evapotranspiration was computed using CropWat 8.0 software. TMS 090581 had the highest tuber productivity of 1.64 kg/ m³ , 3.77 kg/m³ and 3.05 kg/m³ and the highest average tuber yield value of 5.68 t/ha,16.06 t/ha and 18.75 t/ha at 90, 120 and 150 DAP, respectively. TMS 920326 resulted in the highest stem productivity of 1.98 kg/m³ and 2.72 kg/m³ at 90 and 150 DAP respectively while TMS 30572 had the highest stem productivity of 2.59 kg/m3 at 120 DAP. The highest leaf productivity of 1.94 kg/m³ was attained by TMS 980505 at 90 DAP while TMS 30572 yielded the highest leaf productivity values of 2.32 kg/m3 and 2.02 kg/m³ at 120 and 150 DAP, respectively. Despite being susceptible to white flies, TMS 30572 yielded the highest number of nodes, resulting in increased leaf production. TMS 090581 is recommended for tuber water productivity, and TMS 30572 and 980505 for leaf and stem productivity in water- scarce environments.

Design and fabrication of a waste plastic filament extruder

M. Ogbonnaya — 2024-10-25

Plastic pollution causes serious environmental issues and endangers the health of humans and animals in both land and aquatic environments. Despite the fact that Nigeria produces hundreds of tons of plastic waste every day, a greater proportion still finds its way back into the ecosystem because only a small portion of it is recycled. Nigeria's growing production of single-use plastics and careless disposal of plastic waste into the land and ocean are the main causes of the country's growing plastic pollution problems.. For this reason, recycling and reusing plastics is necessary to lessen the harmful effects that plastic utilization has on both human and the environment.. Plastics can be recycled into filaments used in 3D printing also known as additive manufacturing. In this study, a plastic filament extrusion machine for waste plastic was designed and developed with the aim of recycling high-density polyethene, thereby lessening the negative environmental effects that come with disposing of it.. The basic components of the extruder comprised of a hopper, screw, barrel, die, and motor system. Temperature, oxygen, and shear stress all cause the plastics to deteriorate during the extrusion of plastics for filament.. Thus, this study examined the impact of different extrusion temperatures on the filament quality made from high-density polyethylene polyethene (HDPE). The plastic pellets melt and flow into the die as a result of friction between them and the barrel surface and the heat generated by the heating bands. Plastic filament was extruded with a combination of optimal pellet compression, temperatures between 150 and 230 degrees Celsius, and a gradual increase in the pressure of the molten pellets inside the barrel.. Melted plastic adhered itself to the barrel at low temperatures but turned to char at high temperature. Consequently, in order to produce quality 3D filament using HDPE, it is imperative to maintain acceptable temperature conditions. Based on the results, the extruder produced excellent filament suitable for 3D printing at 200 oC. The results of this study emphasize the significance of temperature regulation during the extrusion process in order to guarantee the intended filament quality.