Master of Science (M.Sc.) Theses and Dissertations

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    Open Access
    Studies of some quality parameters of dried paraquetina nigrescens. L. leaf
    (Department of Food Science and Technology, Faculty of Technology, Obafemi Awolowo University., 2023) AYODELE, Esther Adeyinka
    The study investigated the drying kinetics of African parquetina (Parquetina nigrescens) leaves at three different temperatures and evaluated the effect of various drying conditions on its phytochemical, proximate, antioxidant and mineral properties. It also assessed the storage stability of the dried leaves. These were with a view to examining the effect of using various drying temperatures on the chemical composition and rehydration assessment of Parquetina nigrescens leaves. Freshly harvested Parquetina nigrescens young leaves were destalked, washed, drained and sliced. Leaves were sun dried and oven dried at 50, 60 and 70 oC and weighed at 5, 10, 15, 30 and 60 mins intervals until a sample weight remained unchanged. The dried samples were pulverized into fine powder particle size. Drying data obtained were fitted into five thin layer drying models (Newton, Page, Henderson and Pabis, Logarithmic and Modified Henderson and Pabis). The phytochemical, proximate, mineral and antioxidant properties in both fresh and dried Parquetina nigrescens leaves were determined in accordance with standard procedures. Rehydration capacity was determined at four temperature levels of 30, 60, 70 and 80 o C. The data generated in this study were examined using appropriate descriptive and inferential statistics. The results obtained showed that moisture content reduced as temperature and time increased. The effect of drying temperature on the leaves was significant (p<0.05) up to 105 min after which the drying weight was constant. The proximate composition of the dried leaves indicated; crude protein, total ash, moisture content, crude fibre, fat and carbohydrate content in the range of 5.09 - 5.85%; 51- 0.64%; 9.14 - 9.55%; 1.75 - 1.93%; 1.10 - .24% and 79.47 - 82.06% respectively. For mineral constituents, it was found that: calcium, phosphorus, sodium, magnesium, zinc, copper and iron were in the range of(5.05-5.14, 0.08-0.81, 80.18-87.17, 3.31- 4.64, 0.67-8.02, 1.33- 2.11 and 0.22-0.96 xvii mg/100g, respectively). The antioxidant properties of the leaf samples indicated that Ferric Reducing Power (FRAP), Metal Chelation Activity (MCA) and1,1diphenypicylhydrazine (DPPH) are in the range of 0.27- 0.40, 53.16 -71.45 and 20.14 - 37.67, respectively. The pH of the stored dried leaves ranged between 6.15 - 7.56. The phytochemical properties present, indicated (flavonoid 151.41-170.77mg/100g), (phenol12.50 –17.81mg/100g), (glycosides 0.62 –5.54mg/100g), (alkaloid 0.22-0.98mg/100g), (triterpene 165.08-185.92mg/100g (steroid111.1 - 127.0mg/100g), (tannin 2.6-6.00mg/100g), (saponin 0.94- 1.01mg/100), (terpenoid 1.10 - 17.81mg/100g) and (coumarin 4.12--15.43mg/100g) respectively. In addition, it was confirmed that storage time lower the rehydration capacity and high in rehydrating temperatures, increased the rehydrating capacity of the dried leaves. The study concluded that sundried samples had better quality attributes than oven dried samples while oven dried leaves at 70 o C indicated the best quality out of the three temperature used.
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    Embargo
    Laboratory investigation of factors influencing toxic air emissions from applied paints in the indoor environment.
    (Department of Chemical Engineering, Faculty of Technology, Obafemi Awolowo University, Ile-Ife, Nigeria, 2024) Aremu, Aminat Damilola.
    This study characterized common commercial paints for air pollutants in the indoor environment, and determined emission factors of the identified air pollutants from applied paints. It also modeled emissions of the identified air pollutants and developed a control pathway for toxic air pollutants. These were with a view to determining air pollutants from applied paints in the indoor environment. Some common commercial paints from Nigeria market were selected and characterized using gas chromatography mass spectrometry (GC-MS) and high-performance liquid chromatography (HPLC) analysis. Gaseous and particulates emissions associated with the selected paints were characterized by painting selected experimental chambers using method of spraying painting and air brushes. Experimental measurements of air pollutants associated with the use of the selected commercial paints in indoor environment was carried out using air monitoring equipment. Emission factors of air pollutants were determined using standard mathematical correlations from AP-42. Suitable Specific Models were used to model emissions of toxic air pollutants subject to variables [time (t), temperature (T), relative humidity (RH), total volatile organic compound (TVOC) and particulate matter (PM)]. The obtained concentrations of toxic air pollutants from combinations of the exposed paint and exposure period were compared with the national ambient air quality standards (NAAQs) to determine their level of compliance and also to propose the policy framework for control of paints used in indoor applications in Nigeria. The results of GC-MS and HPLC characterization confirms the presence of VOCs and aromatic hydrocarbons such as benzene, toluene, ethyl-benzene, isomeric xylenes, styrene (BTEXs), phenols and carboxylic acids which constitute a significant class of air pollutants in tested paints. Experimental results showed that toxic air pollutants emissions from selected paints were more concentrated at the source. The design models used showed that pollutants emissions from applied water-based paint followed Quadratic model and that RH, t and PM were significant to particulate matter emission factor (PM-EF) while RH, TVOC and PM were significant to total volatile organic compound emission factor (TVOC-EF). For oil base paint, the design models used showed that pollutants emissions from applied paint followed 2FI model and that T, t, TVOC and PM were significant to particulate matter emission factor (PM-EF) while T, t, TVOC and RH were significant to total volatile organic compound emission factor (TVOC-EF). This study established that for applications in indoor environments, water-based paint is better and safer than oil-based paint with regards to safe period. Also, factors influencing toxic air pollutants emissions from common commercial paints applied in the indoor environment were evaluated. In addition, a quick, easy, and low-cost model was designed to forecast the emissions of toxic air pollutants from paint products in indoor environment based on time and distance. Further, methods and techniques for reducing and controlling toxic air pollutant concentrations from commercial paint applications were highlighted, and current developments to address and enhance indoor air quality (IAQ) were outlined.
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    Development of a Drug Recommender System
    (The Department of Computer Science and Engineering, Faculty of Technology, Obafeim Awolowo University., 2024) EGBI, Alilu Grace
    This study elicited and analysed data on patients, drugs and disease. The study then designed a drug recommender model, implemented the model and tested the performance of the system. These were with a view to developing a drug recommender system that recommends appropriate drug(s) for the treatment of an ailment. Patients’ data were elicited from Medical Information Mart for Intensive Care – IV (MIMIC-IV), a deidentified clinical data of patient admitted in ICU at Beth Isreal Deaconess Medical Center (BIDMC). Drugs data were elicited from Drugs.com. Disease treatment knowledge were elicited from the guidelines on the treatment of Peptic Ulcer Disease (PUD) provided by the Japanese Association of Gastroenterologists. These data acquired were analysed using various functions in the Pandas library. The model for the recommender system was designed based on the Hybrid recommendation approach by combining clustering algorithm, Collaborative filtering approach (CF) and Knowledge-Based filtering approach (KBF). The factors that were considered for recommending appropriate drugs were age of patient, gender of patient, body weight, allergies and drug interactions. The model designed was implemented using the Python Programming Language version 3.6.3 with Flask framework for web development and Visual Studio Code as the Integrated Development Environment (IDE). And the performance of the system was evaluated using Precision, Recall, and Root Mean Squared Error (RMSE). The evaluation was carried out in two phases; Firstly, the CF component was evaluated by splitting the dataset from MIMIV-IV into 70% (60,018) train set and 30% (25,722) test set. Secondly, the KBF component was evaluated using 30 different cases. The evaluation for this was computed manually by comparing the recommendation results from the system with that of an expert. For the CF aspect of the DRS, the system had a precision score of 85.48%, a recall score of 85.58% and a RMSE score of 0.74. The precision result shows that the system has an 85.48% bability in making relevant recommendations. The recall score shows that the system has an 85.58% ability in recommending relevant drugs from all available relevant drugs. The RMSE score of 0.74 shows that the recommended drugs are far from the actual drugs prescribed. For the KBF aspect of the DRS, the system achieved a Precision of 77%, a recall of 83% and a RMSE of 0.24. The system’s Precision and Recall scores were lower when the KBF was added. This study concluded that the addition of the KBF reduced the error rate between actual recommendations and predicted recommendations. So, the system had a high ability in recommending appropriate drugs for PUD.
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    Open Access
    Simulation and optimization of blending ratio of fossil fuel and scrap tyress in cement production
    (Department of Chemical Engineering, Faculty of Technology, Obafemi Awolowo University., 2022) ABUBAKAR, Waheed Adewole
    This study determined the effect of scrap tyres as a complementary fuel and fossil fuel mixtures on kiln operation stability, desired specific heat value and impact on environment, optimised the complementary fuel to fossil fuel mixture ratio and developed mathematical models for minimum energy consumption and emissions. These were with a view to achieving energy and cost savings by co-consumption of scrap tyres with fossil fuel in cement manufacturing facility. The samples of limestone, which is the basic raw material, were obtained from different mines and analysed to determine their compositions using X-ray Fluorescent equipment. The compositions of fossil fuel and scrap tyres were obtained from Nigerian Gas Company and the literature respectively. The prices of raw materials and fuels were obtained from BUA Cement Plc’s Procurement department. The composition of raw materials, fuels and their prices were inserted into the mathematical model equation to determine the minimum cost of cement manufacturing. The modelling optimized the blending ratio of fossil fuel and scrap tyre and takes into account the stable kiln operation by ensuring the clinker parameters were within the targeted values and minimum gas emission. The results of Particle Swarm Optimization modelling showed 36% of fossil fuel was substituted with scrap tyres as a complementary fuel. The cost of manufacturing 1 tonne of cement was $69 using fossil fuel with the blend of scrap tyre compared to using fossil fuel only, which was $73 per tonne. Simulation results showed a reduction in specific heat consumption and SO2 gas emission as the scrap tyre substitution increases. Optimum blending of fossil fuel and scrap tyres was achieved with all the parameter within the targets. This study concluded that blending of scrap tyres as a complementary fuel with fossil fuel in rotary kiln reduces the cost of cement manufacturing without compromise in the product quality and operation stability.
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    Open Access
    Investigation of groundwater seepages using geotechnical and ground penetrating radar techniques
    (Department of Civil Engineering, Falculty of Technology, Obafemi Awolwo University, Ile Ife, 2022) BOBOLA Damilola Gbadebo
    This study evaluated the geotechnical properties of the soil in the study area, determined the stratigraphy, zone of fractures (micro and macro) and cavities with ground penetrating radar, correlated results obtained from the ground penetrating radar investigation with the geotechnical tests of the soil and developed a basemap for the study area for exposition of fractures and cavities zones using information obtained from the geotechnical and ground penetrating radar investigations. These were with a view to determining the causes of groundwater seepages in the study area using geotechnical and ground penetrating radar techniques. Five trial pits, each 3.6m deep were dug in the study area and soil samples were collected at 3.6m from each pit. Sieve analysis, natural moisture content, specific gravity, Atterberg’s limits, compaction, shear strength, permeability, and consolidation laboratory tests were carried out on them to determine their geotechnical properties. The Ground Penetrating Radar (GPR) survey data were acquired using a Geophysical Survey System Incorporated Sirveyor-3000 (GSSI SIR-3000) equipment with a central antenna frequency of 100, 200 and 400 MHz along 10 traverse lines and the data were subjected to processing by the Radpro software. The properties of the soil samples were then statistically analysed and correlated using Microsoft Excel Software Package. The vertical and horizontal stresses acting close to the fractured zone were also analyzed. Critical fracture delineated by GPR was then subjected to further geophysical investigation using Puqi Water Trace Detector (PQWT) instrument and a basemap showing zones of fractures and micro-fractures was generated. Three types of soils were identified based on Unified Soil Classification System (USCS): Silty Sand (SM), Clayey Sand (SC) and Clay with low plasticity (CL), with plasticity for all the soil samples ranging from low to intermediate plasticity from the result of the geotechnical investigation. Also the shear strength of the soils were low to medium ranged with low permeability. The GPR radargrams delineated four subsurface layers. These include the top soil, weathered layer, partly weathered/fractured bedrock and the basement bedrock. Along traverses 1, 6, 8 and 10, geological structures (fractures and micro-fractures); which facilitated groundwater seepages were delineated from the radargrams. A critical fracture denoted as F1 with width of atleast 2 metres was delineated by GPR in traverse line 1 along with one other fracture (with width close to 1.2 metres) and one micro-fracture (few centimetres wide). Several other micro-fractures were also delineated in other traverse lines. Correlation of some of the geotechnical properties of the soil samples show that, soils in the study area substrata with lower percentage of fines, are more prone to groundwater seepage, as they are more permeable and have high shear strength. Analysis of vertical and horizontal stresses of the subsurface close to fracture F1 showed that the weathered and partially weathered layer in the substrata of the study area are more prone to easy flow of groundwater seepage due to high vertical and horizontal stresses. Furthermore, mapping of the critical fracture F1 with PQWT instrument gave a profile map that delineated five distinct layers with varying density up to a depth of 150 m. Also, another fracture of 3 m width was observed directly under the fracture F1 delineated by GPR starting at a depth of 125 m below the ground surface. This wide fracture serves as a conduit for movement of groundwater to the subsurface as the fracture cut across the other subsurface layers. The study concluded that the basement floor was constructed close to a fractured bedrock leading to the incessant seepage of groundwater into the structure’s basement