Faculty of Engineering, Technology, Applied Design & FineArt (FETADFA)

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Open Access
A new combined analytical–numerical probabilistic method for assessing the impact of DERs on the voltage stability of bulk power systems
(Energy reports, 2024) Wanjoli, Paul; Moustafa, Mohamed M. Zakaria; Abbasy, Nabil H.
The integration of distributed energy resources (DERs) and unpredictable loads has increased uncertainty in power systems. Traditional methods struggle to assess performance under these uncertainties, and existing probabilistic methods face challenges with complexity and accuracy. This paper introduces a new combined analytical–numerical probabilistic method to assess the impact of DERs on voltage stability. Using Bayesian Parameter Estimation (BPE), the method derives the analytical properties of random variables (RVs) associated with DERs and loads, obtaining posterior distributions. The Metropolis–Hastings sampling technique then estimates these posteriors numerically, enabling accurate predictions of DERs and load outputs. Voltage stability analysis was performed using the continuation power flow method and validated on the IEEE 59- bus test system in MATLAB/Simulink. The results show that integrating DERs significantly improves voltage stability. The proposed method outperforms the Monte Carlo simulation (MCS)-based method in accuracy and computational speed, increasing DERs penetration and voltage stability limits by 3%. It closely matches MCS voltage estimates but requires fewer iterations (500 per loading increment) compared to MCS’s 1000, leading to faster computation times (a few hours to one day versus up to three days for MCS). This method provides an efficient solution for managing uncertainties in power systems.
Open Access
A Regression Model to Enhance the Profitability of Local Construction Contractors in Uganda
(Journal of Construction in Developing Countries, 2021-08-23) Buhamizo, Isaac; Muhwezi, Lawrence; Sengonzi, Ruth
Doubtlessly, the primary goal of every construction company is to maximise profitability. Without this, construction companies cannot survive. Incidentally, Ugandan local construction contractors (LCCs) continue to collapse in a short period, despite enormous public and private investments in the construction sector. This study investigates the profitability of LCCs in Uganda. An investigation was conducted to develop a regression model that would enable LCCs to enhance their profitability and minimise business failure. A questionnaire survey was conducted to collect primary data from 47 local construction companies registered with the Uganda National Association of Building and Civil Engineering Contractors (UNABCEC) and secondary data were collected from audited books of accounts covering from year 2016 to 2018. Thirty-five valid responses were received, representing a response rate of 74%. Data were coded into SPSS version 25, analysed and displayed using the relative importance index (RII), statistical correlation and regression analysis. The findings indicated that the profitability of LCCs was unsatisfactory when compared to the profitability ratios recommended for the construction industry and those of contractors in other countries. The results also indicate that the profitability of LCCs is significantly affected by the timeliness of payments, cost of f inance, competitive bidding environment, project delays, price fluctuations and corruption tendencies, in that order. The findings of this study will benefit construction industry players by providing awareness about the factors affecting the profitability of LCCs. A regression model to enhance profitability was developed using regression analysis. This will help LCCs enhance their profitability by developing mitigation strategies that prevent low profitability; consequently, business failure will be minimised.
Open Access
A state-of-the-art review on the modeling and probabilistic approaches to analysis of power systems integrated with distributed energy resources.
(Ain Shams Engineering Journal, 2024) Wanjoli, Paul; Abbasya, Nabil H.; Moustafa, Mohamed M. Zakaria
Modern power systems are shifting toward decarbonization and incorporation of distributed energy resources (DERs) to replace fossil fuel generators. Although promising, DERs introduce uncertainty because of their intermittent nature. This study provides a comprehensive survey of current approaches for modeling system uncertainties and methods of analysis, particularly in the context of static voltage stability studies within modern power systems. Emphasis is placed on evaluating various models applied to different system random variables (RVs), focusing on their suitability for those particular RVs. Additionally, the study examines the characteristics and frameworks of prominent probabilistic methods (PM), evaluates their efficacy, and discusses static voltage stability analysis approaches, emphasizing solution structures and appropriate applications. It concludes by thoroughly reviewing both numerical and analytical PM methods and offering insights into their strengths and limitations. The provided comprehensive survey reveals that, considering system uncertainties, voltage stability studies have gained the most share, followed by small-signal stability studies, whereas the frequency stability studies have gained the least share.
Open Access
Advanced machine learning models for the prediction of ceramic tiles’ properties during the firing stage
(Scientific Reports, 2025) V. Vasic, Milica; Awoyera, Paul O.; Fadugba, Oladlu George; Barisic, Ivana; Nettinger Grubeša, Ivanka
The firing stage is a critical phase in ceramic tile production, where the interplay of raw material composition and thermal treatment determines essential properties such as water absorption (WA) and bending strength (BS). This study employs advanced machine learning (ML) models to accurately predict these properties by capturing their complex nonlinear relationships. A robust dataset of 312 ceramic samples was analyzed, including variables such as particle size distribution, chemical and mineralogical composition, and firing temperatures ranging from 1000 to 1300 °C. Among the four ensemble ML models evaluated, CatBoost demonstrated the highest predictive performance. Model accuracy was assessed using multiple evaluation metrics, including the coefficient of determination (R²), root mean squared error (RMSE), mean absolute error (MAE), and mean absolute percentage error (MAPE). To enhance interpretability, SHapley Additive exPlanations (SHAP) were used, revealing that clay mineral content and SiO₂ concentration were the most influential factors for WA, contributing approximately 40% and 30%, respectively. For BS, firing temperature (35%) and Al₂O₃ content (25%) were identified as the key predictors. Partial dependence plots further illustrated critical thresholds, such as a significant drop in WA above 62% SiO₂ and optimal BS values near 1200 °C, findings that align with known ceramic processing principles while offering new, data-driven formulation insights. These results demonstrate the value of explainable artificial intelligence (AI) in enabling real-time process optimization, enhancing product consistency, and supporting energy-efficient ceramic manufacturing. Future work will focus on extending the dataset to include a wider variety of clay compositions and investigating hybrid modeling approaches to further improve predictive performance.
Open Access
An expert analytical approach to reducing construction project delays from ineffective scheduling
(KIU Journal of Science, Engineering and Technology, 2025) Joseph, O. S; Fadugba, O. G; Oluyemi-Ayibiowu, B. D; Uduebor, M. A; Olu-Matins, O. A
The study investigated the effects of ineffective scheduling on the completion of construction projects, identified causes of poor planning and scheduling, and provided expert-recommended solutions. Using a mixed-method approach including online surveys, physical questionnaires, and statistical analysis (Relative Importance Index - RII, Reliability Test, and SPSS), the research analyzed data from 130 construction professionals in Nigeria. The most significant effects of ineffective scheduling were "Time Overrun" (RII = 0.8892) and "Cost Overrun" (RII = 0.8246), followed by "Compromise of Project Quality" (RII = 0.8077). The top causes identified were "Poor Decision-Making Regarding Activity Criticality" (RII = 0.8631), "Lack of Finance for Project Execution" (RII = 0.8492), and "Lack of Expertise in Scheduling" (RII = 0.8123). The study concludes by offering a comprehensive roadmap for stakeholders to enhance scheduling efficiency, reduce delays, and improve overall project performance through practical strategies such as accurate cost estimation, effective planning, stakeholder engagement, and the use of scheduling software.
Open Access
Analyses of Bioretention Systems for Removal of Stormwater Pollutants
(Journal of Ecological Engineering, 2024) Sholagberu, Abdulkadir T.; Nuwagaba, Emmanuel; Tibenderana, Philip; Terseer, Ako; Bainomugisha, Jonan; Twesigye-omwe, Moses N.; Agwe, M. Tobby; Oluwatosin, Olofintoye O.
Stormwater transports directly into rivers eroded soil, animal wastes, pesticides, fertilizers and other potential pollutants. Bioretention is often designed to capture and treat it using the natural properties of soil and plants. However, selection of appropriate media structure and plants need to be adequately studied. This study investigated the performance of bioretention system in removing stormwater pollutants using Dracaena, a local plant, also called Song of India Plants. Physical model of three Columns A, B and C were developed having five layered filter media of different configurations whose materials were analyzed to meet the design standards. The plants were introduced into Columns A and C leaving out B as control experiment. The quality parameters were determined before and after treatments at ages 10, 20, 30and 40 days when Dracaena plants were introduced into bioretention models. The results showed that the bioretention model drastically improved stormwater quality by reducing values of electrical conductivity, total coliforms (TC), fecal coliforms (FC), total suspended solids (TSS) and biochemical oxygen demand (BOD) as compared to the tested raw stormwater samples. The filter media in both Columns A and C substantially reduced the pollutant levels to standard discharge limits for all parameters tested such as TSS, TC, FC, BOD and nitrates. BOD fell within the recommended standard after 20 days of treatment in Column C with considerable reduction in TC and FC by 68.9% and 75.4% respectively when compared to raw stormwater sample. However, Column C completely removed TC and FC at 40 days which are pathogen indicators in wastewater. This study would be useful to the stakeholders for sustainable stormwater treatment and management.
Open Access
Analysis of Leaching Rate of Heavy Metals from Fly Ash at Varying Leachant pH & Cumulative Liquid to Solid Ratios
(i-manager’s Journal on Material Science, 2020) Tobby, Micheal Agwe; Sharma, S. N.; Pandey, Govind
Fly ash (FA) is a particulate matter consisting of finely divided, non-combustible particles obtained from the flue gases arising from combustion of coal, accounts for over 80% of the total ash produced during coal combustion. In 2018 alone, about 780 million tons of FA has been generated globally, of which voluminous quantity remained unutilized, hence dumped into the environment. This continued disposal of FA into the environment makes the heavy metals contained therein to move out in the leachate generated, polluting the soil, surface and ground water sources among others. In this study, 5 sets of leaching test columns were packed with an equal quantity of air dried fly ash samples and each of them leached with leachant of pH 5.87, 6.08, 6.41, 6.46 and 7.01 and eluate from each column collected at cumulative liquid to solid (L/S) ratios in l/kg of 0.1, 0.2, 0.5, 1.0 and 2.0. Analysis of the eluate for Copper (Cu), Selenium (Se), Zinc (Zn), Cadmium (Cd), Lead (Pb), Nickel (Ni), Chromium (Cr) and Arsenic (As), revealed that the concentrations of Se at Selenium L/S of 0.1 for leachant pH of 5.87, 6.41 and 7.01, exceeded the allowable limits for non-hazardous wastes disposal into the landfills.
Open Access
Antistripping potential of cement kiln dust on recycled asphalt pavement. Innovative Infrastructure Solutions
(Springer Nature., 2025) Usman, Kabiru Rogo; Ali, Atheer Muhammed; Wakawa, Yakubu Mamman; Usman, Abbas
Cement kiln dust (CKD) is the by-product of cement manufacturing. It is collected using air pollution control devices (APCDs) also known as electrostatic precipitators in the form of fue dust to minimize environmental hazards. This study investigates the potential use of CKD as a fller material and its novel antistripping properties on recycled asphalt pavement (RAP). CKD's chemical properties, make it desirable for improving stripping resistance of asphalt in areas prone to high rainfall or moisture exposure, but its application in RAP remains a grey area to explore. Its dual role in improving both adhesion and mechanical properties of asphalt makes it particularly advantageous, in terms of sustainability, cost and resource efciency. The rising production cost, environmental safety concerns, and the push towards sustainable consumption/ production seek alternatives for traditional antistripping agents for asphalt production, thus, CKD. This study prepared densegraded asphalt concrete with nominal maximum aggregate size (NMAS) of 14 mm with 1%, 3%, and 5% of CKD by weight of RAP according to Malaysian standard. A total of fve (5) asphalt concrete (AC14) mixtures were produced with an optimal 3% CKD used in the modifed mixtures at the optimum binder content (OBC). The antistripping properties of CKD in hot mix asphalt (HMA) were assessed through indirect tensile strength test (ITS), indirect tensile stifness modulus (ITSM) and boiling tests on the asphalt mixtures. In addition to the physical, mechanical, chemical, and structural/morphological tests, the safe inclusion of CKD in terms of heavy metals was evaluated by applying toxicity characteristic leaching procedure (TCLP) test. The fndings confrm that CKD meets ASTM C150 standards for type II and type IIA hydraulic cement for use as a fller in asphalt. The fatigue cracking resistance, antistripping resistance in terms of the tensile strength ratio (TSR) & indirect tensile stifness modulus (ITSM) tests indicated that CKD modifed RAP mixes performed better than the control (CNTRL), RAP only and CKD modifed RAP mixes. It also compares favourably with CNTRL+CKD mixture. Ultimately, the boiling test results indicated that CKD blended RAP mix surpassed the minimum 80% TSR for moisture damage resistance.
Open Access
Assessment on Power Distribution Network Planning in sub-Saharan Africa
(IEEE, 2021) Michael, E. Irechukwu; Michael, N. Irechukwu; Samuel, S. Mushakangoma
Power system distribution network planning (PSDNP) encompasses several tasks including ensuring sufficient substation capacity and distribution capacity for the end users. Both rural communities and urban dwellers benefit when there is a well-planned distribution network. City power consumers enjoy stable electricity supply and the number of annually connected rural households increases with an efficient planning scheme in place. However, this is not the case in many cities and rural areas in sub-Saharan Africa. Poor distribution network planning by many power utilities has led to the annual energy demand growing at a much higher rate than the number of electrified households in many sub-Saharan African countries. Therefore, this paper discusses challenges faced by power utilities and energy consumers due to poor distribution planning techniques. This paper proposes an implementation plan to address the inefficient planning challenges faced by the rural communities and urban dwellers. After that, a case study is selected in East Africa, and the solutions are applied.
Open Access
Bamboo stem ash as a sustainable cement replacement in lightweight foam mortar enhancing mechanical thermal and microstructural properties.
(Scientific Reports, 2025) Mydin, Md Azree Othuman; Azman, Nurul Zahirah Noor; Awoyera, Paul O.; Özkılıç, Yasin Onuralp; Fadugba, Olaolu George; Abdullah, Mohd Mustafa Al Bakri; Omar, Roshartini; Datta, Shuvo Dip
This study presents a novel approach to enhancing the properties of lightweight foam mortar (LFM) by utilizing bamboo stem ash (BSA) as a partial cement replacement. Unlike traditional supplemental cementitious materials (SCMs) like fly ash or silica fume, BSA provides a special blend of lightweight properties and a high silica concentration. Thus, the effect of BSA (in proportions of 0–25% and steps of 5%) on the mortars’ fresh, hardened, microscale properties, such as workability, density, strength, durability, and microstructural characteristics, was explored. At 15% BSA replacement, the compressive strength reached 8.25 MPa at 28 days, 7% higher than the control mix (7.7 MPa). The study identifies 15% BSA as the optimal replacement level, striking a balance between mechanical strength, durability, and thermal insulation. Beyond 15%, increased porosity begins to reduce strength, while thermal resistance continues to improve. Thus, a 10–15% replacement range is recommended for applications requiring structural integrity and insulation. The density of the foam mortar decreased from 1000 kg/m3 for the control mix to 960 kg/m3 at 20% BSA replacement, improving the material’s lightweight characteristics. Also, the porosity increased from 24.8% (control) to 30.2% (25% BSA), positively influencing thermal insulation properties. Thermal conductivity measurements indicated a reduction from 0.25 W/mK (control) to 0.18 W/mK at 25% BSA replacement, demonstrating improved thermal resistance. BSA incorporation improves the pore structure and fosters stronger interfacial bonding within the matrix, especially at 15% replacement, according to microstructural investigation using SEM. The water absorption rate increased slightly from 18.2% (control) to 21.6% (25% BSA), still within reasonable bounds for lightweight construction applications. As demonstrated by the mortars’ notable performance, BSA may effectively replace OPC in LFM, improving its mechanical, thermal, and environmental qualities. With the results, BSA has shown potential for developing eco-friendly building materials and aiding in reducing carbon emissions in the built environment. These results show that BSA can be a green and practical substitute for OPC in lightweight building applications, especially for prefabricated panels, insulation layers, and non-load-bearing walls. Its ability to enhance mechanical strength while reducing thermal conductivity makes it a promising material for energy-efficient and sustainable building solutions.
Open Access
Battery Management System for Solar Power Plants in Uganda: An IoT-Driven Approach
(MECS Press, 2025) Ssembalirwa, Denis; Cartland, Richard; Bature, U. I.; Kitone, Isaac
In Uganda, the efficiency and reliability of solar power plants are often compromised due to inadequate battery management, leading to reduced battery lifespan and suboptimal performance. To address this challenge, this project develops and prototypes a smart Battery Management System (BMS) tailored for solar power plants. The system continuously monitors key battery parameters, including voltage, load current, and temperature, while leveraging Internet of Things (IoT) technology for real-time data transmission and remote monitoring. Intelligent algorithms autonomously regulate charging and discharging cycles to prevent overcharging and deep discharge, optimizing battery performance. Testing demonstrated that the BMS significantly improved battery lifespan and energy efficiency by disconnecting charging at 100% and isolating the load at 10% discharge to prevent battery degradation. Additionally, the system disconnects power when battery temperature exceeds 30°C (ambient temperature: 25°C) and detects abnormal current levels above 0.16A to mitigate faults such as short circuits. These automated protections enhance battery reliability and longevity. By implementing proactive battery management strategies, the developed BMS contributes to more efficient and resilient energy storage systems, promoting sustainable energy development in Uganda.
Open Access
Bibliometric Insights into Advances in Nondestructive Testing Techniques for Delamination Detection
(Mesopotamian Journal of Civil Engineering, 2025-04-11) Abdulwahd, Abdulrazaq. K.; Mugisha, Simon; Chavula, Petros; Kayusi, Fredrick
This study presents a comprehensive bibliometric analysis of advances in nondestructive testing (NDT) techniques for delamination detection, based on 4,382 publications indexed in Scopus from 2021 to 2025. Using advanced bibliometric methods and the biblioshiny package in R, the analysis evaluates annual scientific production, citation trends, thematic focus, and collaboration patterns. The results reveal a peak in research output in 2024, followed by a marked decline in 2025, alongside a steady decrease in average citations per article. “Delamination,” “composite,” “ultrasonic,” and “infrared thermography” are identified as core research themes. The field is dominated by a few prolific journals, authors, and institutions most notably in China which account for the majority of scientific output and impact. These findings illuminate evolving research priorities, highlight central contributors, and offer critical perspectives on the development, concentration, and future directions of NDT for delamination detection.
Open Access
Clean eco-friendly cooking energy as sustainable approach and mitigation to climate change: A case study of Ankole, Western Uganda
(Kabale University, 2023-02-07) Kayamba William Kariiti
The study investigates how communities in the Ankole region, western Uganda are coping with a shortage of cooking fuels, climate change and what strategies they have set up to counteract its effects using innovative, sustainable, renewable and affordable technological methods. The objectives of the study are: 1) to investigate the type of cookstoves used in cooking that is being used in the area under study. 2) To suggest eco-friendly cook stoves that can be used for cooking to save the environment and reduce health hazards that are related to inhalation of smoke. It was carried out in the districts of Mbarara and Bushenyi which are diverse in their setting. The main objective was to investigate how traditional cooking fuels have become a health hazard to many mothers and children in Ankole, human activities and rural-urban migration, have caused hiking of prices for fuel for cooking; wetland drainage, bush clearing for farming, charcoal burning, brick making associated with social and economic developments have affected the environment. Traditional methods of cooking still dominate in Ankole, where three stones are still used. Charcoal has become a major fuel for cooking in many homes as an alternative to firewood, in addition to briquettes, biogas, LPG and volcanic rocks. A sustainable eco-friendly stove is proposed to mitigate environmental degradation.
Open Access
Clean Eco-Friendly Cooking Energy as Sustainable Approach and Mitigation to Climate Change: A Case Study of Ankole, Western Uganda.
(Kabale University, 2023) Kayamba, William Kariiti
The study investigates how communities in the Ankole region, western Uganda are coping with a shortage of cooking fuels, climate change and what strategies they have set up to counteract its effects using innovative, sustainable, renewable and affordable technological methods. The objectives of the study are: 1) to investigate the type of cookstoves used in cooking that is being used in the area under study. 2) To suggest eco-friendly cook stoves that can be used for cooking to save the environment and reduce health hazards that are related to inhalation of smoke. It was carried out in the districts of Mbarara and Bushenyi which are diverse in their setting. The main objective was to investigate how traditional cooking fuels have become a health hazard to many mothers and children in Ankole, human activities and rural-urban migration, have caused hiking of prices for fuel for cooking; wetland drainage, bush clearing for farming, charcoal burning, brick making associated with social and economic developments have affected the environment. Traditional methods of cooking still dominate in Ankole, where three stones are still used. Charcoal has become a major fuel for cooking in many homes as an alternative to firewood, in addition to briquettes, biogas, LPG and volcanic rocks. A sustainable eco-friendly stove is proposed to mitigate environmental degradation.
Open Access
Concrete Production and Curing with Recycled Wastewater: A Review on the Current State of Knowledge and Practice
(Hindawi, 2022-12-10) Tobby Michael, Agwe; Tibenderana, Philip; Twesigye-Omwe, Moses N; Abdulkadir, Sholagberu Taofeeq
properly cited. A number of factors have combined to put excessive pressure on the finite available freshwater resources. These include increasing population, rapid urbanization, industrialization, changed land pattern usage and land cover, change in the overall ecological system, and increased temperature and unscientific compromises in the extraction of water are at alarming threshold putting pressure on the finite available freshwater resources. As a result, many countries have been stressed or are at the verge of being stressed. The problem is worsened day by day by prolonged drought, unchecked discharge of untreated or partially treated wastewater to the freshwater reservoirs and lack of proper water quality control measures and management. Many initiatives such as Zero Liquid Discharge of industrial wastewater into freshwater bodies such as reservoirs, lakes, and ponds, and the use of recycled wastewater for irrigation and domestic purposes have started to be embraced as measures to put a check on the fast-depleting freshwater resources for sustainable socio-economic development. The construction industry is the second largest consumer of freshwater just after agriculture. Concreting alone consumes, annually, over one trillion m3 of freshwater globally while the concept of the use of wastewater and/or recycled water in the concrete-making processes is yet to be adopted. Hence, this paper presents a general review of the current state of knowledge and practice on concrete production and curing using recycled wastewater from industrial, commercial, and domestic activities. An extensive review of the existing literature revealed that recycled water is ft for concrete production and curing purposes. The observations made are based on the assessment of wastewater quality parameters and their impacts on some selected concrete properties such as initial setting time and compressive strength. Due to scanty research on the impacts of varying concentrations of different ingredients in any questionable water on selected properties of reinforced concrete and its durability, thus, further research is recommended.
Open Access
Concrete Production and Curing with Recycled Wastewater: A Review on the Current State of Knowledge and Practice
(Hindawi, 2022) Tobby Michael, Agwe; Philip, Tibenderana; Moses N., Twesigye-Omwe; Joel, Webster Mbujje; Sholagberu Taofeeq, Abdulkadir
A number of factors have combined to put excessive pressure on the finite available freshwater resources. These include increasing population, rapid urbanization, industrialization, changed land pattern usage and land cover, change in the overall ecological system, and increased temperature and unscientific compromises in the extraction of water are at alarming threshold putting pressure on the finite available freshwater resources. As a result, many countries have been stressed or are at the verge of being stressed. The problem is worsened day by day by prolonged drought, unchecked discharge of untreated or partially treated wastewater to the freshwater reservoirs and lack of proper water quality control measures and management. Many initiatives such as Zero Liquid Discharge of industrial wastewater into freshwater bodies such as reservoirs, lakes, and ponds, and the use of recycled wastewater for irrigation and domestic purposes have started to be embraced as measures to put a check on the fast depleting freshwater resources for sustainable socio-economic development. The construction industry is the second largest consumer of freshwater just after agriculture. Concreting alone consumes, annually, over one trillion m3 of freshwater globally while the concept of the use of wastewater and/or recycled water in the concrete-making processes is yet to be adopted. Hence, this paper presents a general review of the current state of knowledge and practice on concrete production and curing using recycled wastewater from industrial, commercial, and domestic activities. An extensive review of the existing literature revealed that recycled water is fit for concrete production and curing purposes. The observations made are based on the assessment of wastewater quality parameters and their impacts on some selected concrete properties such as initial setting time and compressive strength. Due to scanty research on the impacts of varying concentrations of different ingredients in any questionable water unselected properties of reinforced concrete and its durability, thus, further research is recommended
Open Access
Concrete Production and Curing with Recycled Wastewater: A Review on the Current State of Knowledge and Practice
(Hindawi, 2022) Tobby Michael, Agwe; Philip, Tibenderana; Moses N, Twesigye-Omwe; Joel Webster, Mbujje; Abdulkadir, Sholagberu Taofeeq
A number of factors have combined to put excessive pressure on the finite available freshwater resources. These include increasing population, rapid urbanization, industrialization, changed land pattern usage and land cover, change in the overall ecological system, and increased temperature and unscientific compromises in the extraction of water are at alarming threshold putting pressure on the finite available freshwater resources. As a result, many countries have been stressed or are at the verge of being stressed. The problem is worsened day by day by prolonged drought, unchecked discharge of untreated or partially treated wastewater to the freshwater reservoirs and lack of proper water quality control measures and management. Many initiatives such as Zero Liquid Discharge of industrial wastewater into freshwater bodies such as reservoirs, lakes, and ponds, and the use of recycled wastewater for irrigation and domestic purposes have started to be embraced as measures to put a check on the fast depleting freshwater resources for sustainable socio-economic development. The construction industry is the second largest consumer of freshwater just after agriculture. Concreting alone consumes, annually, over one trillion m3 of freshwater globally while the concept of the use of wastewater and/or recycled water in the concrete-making processes is yet to be adopted. Hence, this paper presents a general review of the current state of knowledge and practice on concrete production and curing using recycled wastewater from industrial, commercial, and domestic activities. An extensive review of the existing literature revealed that recycled water is fit for concrete production and curing purposes. The observations made are based on the assessment of wastewater quality parameters and their impacts on some selected concrete properties such as initial setting time and compressive strength. Due to scanty research on the impacts of varying concentrations of different ingredients in any questionable water on selected properties of reinforced concrete and its durability, thus, further research is recommended.
Open Access
Determining Bandgap of Thermochromic Phosphor Films via Reflectance Measurements under Controlled Heating.
(Kabale University, 2024) Rwabona, Katashaya Steven
In this article, we present a method to determine the bandgap of a thermochromic phosphor film by simple reflectance measurements under controlled heating. The phosphor is illuminated by a light-emitting diode while being heated continuously. The reflected light is detected using a calibrated photodiode circuit based on an operational transconductance amplifier. We apply the Schuster- Kubelka-Munk function to deduce the absorbance over temperature and thus the bandgap. We show, for the first time, that the thermochromic phosphor's colour change follows Arrhenius's Law and therefore involves activation energy. We estimate the bandgap to be between 1.1 eV and 1.9 eV and find an activation energy of 46.67 ±1.6 kJ/mol. The simplicity of the approach will appeal to undergraduate teachers and students of physics and materials science. The technique can be used to investigate other thermochromic materials as well.
Open Access
Developing High-Performance Low-Carbon Concrete Using Ground Coal Bottom Ash and Coconut Coir Fibre
(Elsevier, 2025) Ahmed, Muneer; Khan, Suliman; Bheel, Naraindas; Awoyera, Paul.O; Fadugba, Olaolu George
This study addresses the need for eco-friendly concrete by incorporating agro-industrial waste, ground coal bottom ash (GCBA) and coconut coir fibre (CF), as partial replacements for Ordinary Portland Cement. A total of150 samples were tested using Scanning Electron Microscopy (SEM), Fourier-transform infrared (FTIR), X-ray Fluorescence (XRF) and mechanical methods. Optimal results were achieved with 4.31 % CF, 0.4 % superplasticizer, flexural performance. The addition of CF reduced cracking and improved durability and GCBA enhanced long-term performance through improved particle packing and pozzolanic reactions. The GCBACF mixtures also lowered embodied carbon by 194 kg CO₂/m³ and energy by 970 MJ/m³, achieving higher Eco efficiency than traditional concrete. This research supports the development of sustainable, high-performance concrete aligned with circular economy and sustainability goals.
Open Access
Development of a fundamental model for pelleting efficiency of an innovative hybrid fish feed processing system
(KIU Journal of Science, Engineering and Technology, 2025) Daniel C., Nnadi; John Chijioke, Edeh; Offiong Alexander, Aniekan; Aniekan, Offiong
The development of a fundamental model for predicting pelleting efficiency at variable feed rates and number of orifices was central to optimizing the performance of an innovative hybrid fish feed processing system. The system was designed for simplicity, quality, and precision in fish feed production. Machine parameters, derived from comprehensive design and parametric analysis, were used to establish input variables for the pelleting efficiency model, including feed rate and number of orifices. With a constant driving force of 713.38 N from a 3 hp electric motor, the system demonstrated pelleting efficiencies of 55 %, 70 %, and 88 % for 15, 20, and 25 orifices, respectively. At a fixed die orifice, increasing the feed rate from 10 to 20 mm/rev at interval of 5 mm/rev resulted in efficiencies of 60 %, 80 %, and 110 %. Evaluation of the combined effect of the factors predicted an optimum efficiency of 86.9 % at optimal settings of 20mm/rev and 15 orifices. The model’s experimental validation, conducted under optimized conditions, showed that the 20-orifice die produced a higher pelleting efficiency (97%) but with reduced pellet floatability, whereas the 15-orifice die yielded an efficiency of 86.21 % and better floatability. The prediction error of 0.69% validated the model’s accuracy at 99 %. In addition, an introduction of cassava starch constituent improved pellet floatability and surface finish. This study therefore, highlights the potential of the developed model to enhance pelleting performance, balancing efficiency and pellet quality, and providing a robust foundation for optimizing fish feed production processes.