LAUTECH Journal of Engineering and Technology https://www.laujet.com/index.php/laujet <p>LAUTECH Journal of Engineering and Technology (LAUJET) is a leading internationally referred journal in the fields of science, engineering and technology. It is a journal founded by academics and educationists with substantive experience in industry. The journal is an online open-access journal with a yearly print version of its volumes/issues made available to interested persons/institutions. The basic aim of the journal is to promote innovative ideas in fields relating to the sciences, engineering and technology. The basic notion of having a wide area of focus is to encourage multidisciplinary research efforts and seamless integration of diverse ideas that might be gleaned from the papers published in the journal.</p> <p>&nbsp;</p> en-US laujet@lautech.edu.ng (Engr. Prof. O.S. Oladejo) tbasafa@lautech.edu.ng (Prof. T. B. Asafa) Thu, 13 Feb 2025 21:16:33 +0000 OJS 3.1.1.4 http://blogs.law.harvard.edu/tech/rss 60 Explainable ensemble deep learning model for predicting diabetic retinopathy based on APTOS 2019 eye pack dataset https://www.laujet.com/index.php/laujet/article/view/774 <p><em>Detection of diabetic retinopathy (DR) as early as possible is vital in mitigating the complicated issues associated with the disease. Recent advances in artificial intelligence (AI), particularly deep learning (DL) techniques, have led to appreciable increase in the accuracy of predicting various disease classes. However, the challenge of AI models is the difficulty in providing insights into how and why a model arrives in attaining decision-making to facilitate trust and adoption in clinical settings. Therefore, this study aimed to enhance the detection rate of DR and explain the significant regions on the image for the model's overall performance. This study utilised Convolutional Neural Networks (CNN), Long Short-Term Memory (LSTM) networks, Simple Recurrent Neural Networks (SRNN), and XGBoost in an ensemble model (EM). Specifically, Shapley Additive exPlanations (SHAP), a popular Explainable Artificial Intelligence (XAI) technique was utilised to identify and provide insights to which parts of the images features that contribute to the model's overall performance. After a series of experiments using the APTOS 2019 eye pack dataset collected from the Kaggle repository to evaluate the performance of CNN, LSTM, SRNN, and XGBoost. The EM outperformed all the other models with 95.63% accuracy, 97.79% precision, 93.64% recall rate, 98.79% F1-score and 97.75% AUC score. Also, SHAP analysis revealed significant regions on the image that influenced predictions, thus showing how important interpretability was for the model. The results imply that the ensemble DL, particularly with XGBoost, enhances the detection of DR, thereby improving the efficiency of screening tests and supporting personalised treatment plans in clinical practice through integrating these advanced models with XAI tools, creating trust towards automated diagnostic systems</em><em>.</em></p> O. Folorunsho, S. E. Akinsanya, O. A. Fagbuagun, S. A. Mogaji, S. K. Raji ##submission.copyrightStatement## https://www.laujet.com/index.php/laujet/article/view/774 Thu, 13 Feb 2025 00:00:00 +0000 Influence of penetration angles on global-thermo-hydraulic-performance of shell and tube heat exchangers with multi-cross sectional tube configurations https://www.laujet.com/index.php/laujet/article/view/754 <p>Shell-and-Tube Heat Exchanger (STHE), a vital component for efficient energy management when used with Straight-Tube Geometries (STG) is associated with low Global-Thermo-Hydraulic-Performance (GTHP). These contribute to the high energy demand of processing plants. The recently developed STHEs with modified tube configurations have not adequately addressed these limitations and necessitated a continuous search for tubes with improved performance. Multi-cross sectional tube geometrical (MSTG) configurations are known to improve GTHP along flow lines. This process has not been thoroughly investigated. Therefore, this study was designed to investigate the influence of penetration angles (PAs) on the STHEs’ performances using MSTG configurations. ; The numerical analysis was evaluated in terms of GTHP indices on STHE with Convergent-Divergent-Tube-Geometry (CDTG) and Divergent-Convergent-Tube-Geometry (DCTG) configurations of varying penetration angles (PAs), 5,10,15,…,90°. Numerical GTHP for STHE with STG was 1.0, while that obtained for STHE with CDTG configurations for all PAs fall between 1.50 to 1.625 with the highest at &nbsp;PA indicating a 50% minimum improvement in GTHP over STHE-STG. For DCTG, GTHP were between 1.43 and 1.585 for all PAs with the highest at &nbsp;PA indicating a 43% minimum improvement in GTHP over STHE-STG. Replacing STHE-STG with STHE-MSTG can improved their GTHPs in processing plant.</p> I. O. Alabi, A. A. Dare, M. O. Petinrin ##submission.copyrightStatement## https://www.laujet.com/index.php/laujet/article/view/754 Thu, 13 Feb 2025 16:02:20 +0000 Influence of ethanol on the spectral properties of natural dyes from microbes: implications for dye-sensitized solar cell performance https://www.laujet.com/index.php/laujet/article/view/766 <p>The increasing need for renewable energy sources that are both sustainable and less costly has spurred growing research into natural dyes as eco-friendly sensitizers for dye-sensitized solar cells (DSSCs). This study entails the extraction and characterization of natural pigments derived from Chlamydomonas starii and Coelastrella sp. focusing on solvent selection and thermal treatment. Ethanol proved much better than ethyl acetate and had the most remarkable effects on retaining functional groups, especially hydroxyl (O-H) and carbonyl (C=O), which would be important in terms of dye adsorption for improved photon absorption and electron injection. Spectroscopic analyses indicated that the ethanol-extracted dyes, especially non-heated and moderately heated ones, would enable a broad absorption of light within the visible spectrum. These findings hence have demonstrated that natural dyes extracted with ethanol were better than those extracted with ethyl acetate, which makes ethanol more efficient, scalable, and greener solvent for extraction of natural dyes compared to ethyl acetate. Future research is to focus on mixed solvent systems and stabilization techniques to improve dye performance even further. This will therefore be the greatest scion towards high-efficiency DSSCs while further supporting the global transition efforts toward sustainable energy technologies.</p> G. M. Lana, V. O. Adenigba, E O. Oyetunji, O. Adegboyega, O. J. Oyewole, I. T. Bello, O. Adedokun ##submission.copyrightStatement## https://www.laujet.com/index.php/laujet/article/view/766 Thu, 13 Feb 2025 00:00:00 +0000 The Assessment of Groundwater Quality for Drinking and Construction uses in Odo-Oba Town,Southwestern Nigeria. https://www.laujet.com/index.php/laujet/article/view/758 Assessment of Groundwater Quality for Drinking and Construction uses in Odo-Oba Town, Southwestern Nigeria. 1Temilade Oladeji and 2Olufunmilayo Adewoye : helenetemi@gmail.com, aoadewoye55@lautech.edu.ng Abstract Groundwater is a crucial natural resource for human survival, serving as the primary source of freshwater worldwide. However, a lack of data on water quality can have detrimental effects on human health and resource management. This study aims investigates the chemical composition of groundwater in Odo-Oba, Oyo State, Nigeria, to assess its quality for drinking and construction. The objective is to evaluate the potential for possible contamination, to determine the water facies type and assess its suitabilityfor sustainable development using water quality indices, plotsand statistical analysis for potable water supply and construction purposes.Twenty groundwater samples were analyzed for physical and chemical parameters and were compared to international standards. Results showed slightly acidic water with moderate temperatures and elevated mineral content. Potassium was the most abundant cation, while chloride was the dominant anion. Most parameters were within acceptable limits, but some samples were unsuitable for drinking. Rock-water interactions significantly influence the water chemistry. While groundwater in Odo-Oba is unsuitable for drinking without treatment, it is suitable for construction. However, further microbiological analysis and proper waste management are crucial to protect groundwater resources. Testing concrete samples for pH changes is recommended to assess potential impacts on structural integrity. Keywords: Assessment, Groundwater, Quality, Construction, Drinking, Suitability T. N. Oladeji, A. O. Adewoye ##submission.copyrightStatement## https://www.laujet.com/index.php/laujet/article/view/758 Thu, 13 Feb 2025 21:23:34 +0000 Unsteady aerodynamic performance of spiked and unspiked aloe vera-inspired aerofoils at low reynolds number https://www.laujet.com/index.php/laujet/article/view/759 <p><em>The increasing demand for Micro Aerial Vehicles (MAVs) and other low-speed aerial platforms has intensified the focus on optimizing aerofoil designs for low Reynolds number applications. This study presents a comparative analysis of the unsteady aerodynamic performance of aloe vera-inspired aerofoils, both spiked and non-spiked, at Reynolds number 1.5 × 10<sup>5</sup>. By employing the Unsteady Reynolds-Averaged Navier-Stokes (URANS) equations alongside the Transition SST (four-equation) turbulence model, the research accurately characterizes the flow field and aerodynamic loads under dynamic conditions. The results indicate that the novel spiked aerofoil exhibits superior performance at all angles of attack, demonstrating delayed flow separation and enhanced lift coefficient and lift-to-drag ratios compared to the non-spiked aloe vera aerofoil.</em></p> Moses Oluwasina Julius, S. Adio, A. Soji-Adekunle, A. Ishaq, T. Akigbade, B. Fatai ##submission.copyrightStatement## https://www.laujet.com/index.php/laujet/article/view/759 Thu, 13 Feb 2025 21:30:40 +0000