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Item Open Access Investigation of flexural strength of concretes containing rice husk and saw dust ashes from different calcination methods(Federal University of Technology, Owerri, 2016-07) Amadi, Stanley OgadinmaThis work investigated the flexural strengths of concretes containing rice husk ash (RHA) and saw dust ash (SDA) from different calcination methods. RHA and SDA were produced using three different calcination methods namely, Open-Air (OA), Furnace (F), and Stove (S). Each of RHA and SDA was used as partial replacement of Ordinary Portland Cement (OPC) at 5%, 10% and 15%. 171 concrete beams of dimensions 150 x 150 x 600mm were produced using 1:2:4 cement–sand–sandstone mix ratio and 0.6 water/cement ratio. This comprised 81 OPC– RHA, 81 OPC–SDA and 9 OPC (control) concrete beams. The beams were cured by immersion and tested for flexural strengths at 28, 90 and 150 days. The results showed that the flexural strength of the blended cement concrete increased with curing age and decreased with increased amount of RHA and SDA. The 150th day flexural strengths for 5% RHA were 5.35 Nmm-2 for OA, 6.74 Nmm-2 for F and 5.20 Nmm-2 for S. Corresponding strengths at 5% SDA were 4.48 Nmm-2 for OA, 5.85 Nmm-2 for F, and 4.28 Nmm-2 for S, while the Control value was 6.41 Nmm-2 . Thus, for 5% replacement of OPC with RHA, OA calcination had 83.5% the strength of the control; F calcination had 105.1% the strength of the control, while S calcination had 81.1% the strength of the control. Similarly, for 5% replacement of OPC with SDA, OA calcination had 69.7% the strength of the control; F calcination had 91.3% the strength of the control, while S calcination had 66.7% the strength of the control. Therefore, although furnace calcination gave higher strength than open-air and stove calcinations, the latter two could still be used for structural members with lower flexural strength.Item Open Access Modelling of thin layer drying characteristics of groundnut seeds (Arachis Hypogea)(Federal University of Technology, Owerri, 2017-10) Obumseli, Pacifine ChiomaGroundnut or Peanut is a legume crop with high nutritive value. Drying of groundnut is necessary in order to reduce the moisture content to a safe storage level and also increase the shelf life. Five thin layer drying models were fitted into the drying curve also the effective moisture diffusivity for groundnut seeds were calculated. Groundnut seeds with an Initial Moisture Content 67% (db) were dried to a safe moisture content of about 14% in a conventional tray dryer at temperatures of 45oC, 55oC, 65ºC, and air velocities of 0.6m/s, 1.0m/s and 1.5m/s .The effective moisture diffusivity was evaluated using Fick’s second law and the dependence of moisture diffusivity on temperature was described by Arrhenius type equation. Comparisons of the drying rate models showed high coefficient of determination for Page model, two-term model, followed by Logarithmic, Henderson and Pabis model, and then the Newton Model of which has high error and low coefficient of determination. The Model equation is MR = exp(-0.00119t) 1.43Item Open Access Analysis of the effects of globalisation on maritime logistics in Nigeria(Federal University of Technology, Owerri, 2024-02) Ndukwu, Ibeawuchi PeterThe study investigated the effects of economic globalization maritime trade and port logistics in Nigeria. The central objective was to determine the significance of the influence of economic globalization on values of seaborne export and import trade, GDP maritime transport, port revenue, ship traffic calls in Nigeria ports, trend ship turnaround time in Nigeria ports, and cargo dwell time trend in Nigeria ports. The study used ex-post facto research designed and secondary data sourced from the Nigeria Ports Authority, Central bank of Nigeria and the International Monetary Fund covering a period of 15 years from 2005 to 2019. The log-linear multiple regression analysis method was used to analyze the data obtained. It was found that while there is significant effect of economic globalization on the value of shipping export trade, value of shipping import trade, GDP maritime transport, port revenue generated in Nigeria between 2005 and 2019; there is no significant effects of economic globalization of maritime logistics indicator variables such as the ship calls in Nigeria ports, trend of ship turnaround time in Nigeria ports, and the trend of cargo dwell time in Nigeria ports. The following empirical models among others were developed showing the effects of economic globalization on maritime logistics in Nigeria: InEXPtrade = 7.484 - 0.428InKOFTRGlDf + 2.046InKOFTRGlDj + 1.95InKOFFGlDj + 0.552InKOFFGlDf + e; InEXPtrade = 23.396 – 2.388InKOFTRGlDf + 8.279InKOFTRGlDj + 3.838InKOFFGlDj – 9.423InKOFFGlDf + e; InIMPtrade = 23.396 – 2.388InKOFTRGlDf + 8.279InKOFTRGlDj + 3.838InKOFFGlDj – 9.423InKOFFGlDf + e; InSHIP traffic = 5.966 + 0.841InKOFTRGlDf - 0.852InKOFTRGlDj + 0.185InKOFFGlDj + 0.486InKOFFGlDf + e; InGDPmaritime = 5.016 -1.21InKOFTRGlDf + 0.503InKOFTRGlDj + 1.623InKOFFGlDj + 0.672InKOFFGlDf + e. The policy implications were discussed and recommendations proffered in line with the study findings.Item Open Access Investigation into graphene as an electrode material in microbial fuel cells for biodiversity generation(Federal University of Technology, Owerri, 2025) Anyanwu, Michael NnamdiThe study investigates the potential of Graphene as an electrode coating material in microbial fuel cells for bioelectricity generation as well as a comparison with other electrode coating materials as copper, oxides, fluorides, carbonates, hydrocarbons, and powdered metal. Driven by the demand for materials with superior mechanical and thermal properties in the realm of advancing technology. Rigorous testing, such as mechanical, physical, chemical, electrical resistance, and defect inspections, were conducted on a Graphene sheet (0.70 x 1200 mm) and compared with copper, carbon isotope values, and NIS standards (NIS-119:1984 and NIS487:2010). State-of-the-art laboratory equipment, such as an atomic absorption spectrometer, coating thickness gauge, universal tensile machine, and defect inspection system, was employed. The findings indicate that most elements in the graphene material align well with standard values, affirming its suitability for intended applications. However, manganese exceeds the standard limit, necessitating further scrutiny and potential refinement in the production process. In the ultimate tensile strength test, graphene surpasses the NIS requirement of 175, registering an impressive 182. The electrical resistivity values also showcase favorable results, with graphene exhibiting 0.02610-6 Ohm/cm compared to the NIS standard of 0.03410-5 hm/cm. Impact resistance, a critical parameter, demonstrates graphene's robustness with a measured value of 5 J, exceeding the NIS range of 2 J - 5 J. The gloss result for graphene falls within the specified NIS requirement of 40-60%, recording 58%. This research significantly contributes to our understanding of graphene’s applicability. It provides valuable insights for optimized production processes and identifies potential applications that demand enhanced mechanical properties. The observed discrepancies, particularly the elevated manganese level, highlight areas for further investigation and process refinement. Overall, the study underscores graphene’s promising role in microbial fuel cells and sets the stage for continued advancements in material science and bioelectricity generation technologies.Item Open Access Determination of structural characteristics of palm kernel shell-sawdust plank laminated composite slab(Federal University of Technology, Owerri, 2024-04) Irhialebholo, VictorThis work investigates the structural characteristics of Palm Kernel Shell-Sawdust-Plank laminated composite slab. The materials used in the laboratory experiments include: Ordinary Portland Cement, river sand, gravel, sawdust, plywood, nails reinforcement bars, stirrups and water. The physical and mechanical characterization tests were performed on the aggregate and sawdust used in this work. Manual mixing operation was adopted and all palm kernel shell –sawdust ingredients where batched by weight. A total of eighteen (18) cubes of size 150 x 150 x150 mm, nine (9) cylinders of size 150 x 300 mm and nine (9) beams of size 150 x 150 x 600mm were produced from mix ratios 1:1:1, 1:2:2, and 1:3:3 for compressive strength test, split tensile strength test and flexural strength test respectively. Also, a total of 32 slabs of size 1200 x1000 x 100 mm, 1200 x 1000 x 125 mm, 1200 x 1000 x 150 mm and 1200 x 1000 x 175 mm were cast for flexural strength of slab from the mix ratios 1:2:2 and 1:3:3. Out of the 32 slabs cast, 16 were produced from palm kernel shell – sawdust wooden plank laminated (25mm as the thickness of wooden plank for the laminate), 8 were produced from normal concrete ingredients (coarse aggregates, fine aggregates, cement and water) with 10mm rebar and mix ratio of 1:2:4. Water-cement ratio of 0.45 was adopted. The remaining 8 slabs were made from plain sawdustquarry dust with mix ratio of 1:3:3. The average compressive strength for the three (3) mix ratios used were 10.25 MPa, 9.08 MPa and 4.36 MPa respectively. The average flexural strength from beams samples for the three (3) mix ratios were 2.35 MPa, 2.00 MPa and 1.85 MPa; that of slab ranges from 1.84-3.17 MPa. The average split tensile strength for three (3) mix ratios are 1.950 MPa, 1.666 MPa and 1.558 MPa. The average static modulus of elasticity for the three mix are 8.90 GPa, 8.56 GPa and 6.77 GPa. The average Poisson’s ratio ranges from 0.19-0.36. The shear modulus ranges from 3.86– 2.64 MPa. The maximum deflection for the slabs were observed to occur at the size 1200 x 1000 x 100 mm no matter the core content of the slab while the minimum deflection occurs at the size 1200 x 1000 x 175 mm. The flexural strength results of slabs were compared by percentage difference and the results shows that there is significant difference between the two sets of slabs. Also comparing the results of plain palm kernel shell –sawdust slab to that of palm kernel shell – sawdust wooden plank laminated composite slab, show that laminates with plywood influence flexural strength up to 62%Item Open Access Effects of project risk factors on procurement selection methods in South East Nigeria: A case of World Bank assisted project(Federal University of Technology, Owerri, 2024) Njoku, Emmanuel ChukwudiSelection of procurement methods without considering the effect of project risk factors has resulted to failure in achievement of sustainable acquisition of goods, works and consultancy services in many organizations. This study on effect of project risk factors on procurement selection methods in South East Nigeria is to improve and enhance selection of procurement methods in World Bank assisted projects. Non probability sampling survey technique was adopted. 400 questionnaires modelled in five point Likert scale were administered on the project team members of the seven World Bank assisted projects. 350 valid responses were obtained and data collected were analysed using component factor analysis, correlation and multiple regression analysis in Statistical Package for Social Sciences to identify, evaluate and rank the essential project risk factors that affect the selection of procurement methods. Principal component analysis were used to extracted four project risk factors namely: project resource and risk avoidance, price certainty for allocation of project responsibility, clients experience in handling project and contract funding arrangement and quality of services. These project risk factors were subjected to multiple regression analysis to determine their respective level of effect in the selection on procurement methods. Results revealed that at a significance level of 0.05, for procurement of goods, works and non consulting services, project completion time and risk avoidance and contract funding arrangement and quality of services ranked first with coefficient value of 0.433. For consultancy services, contract funding arrangement and quality of services had the highest effect on selection of QCBS procurement method with a coefficient value of 0.422 at a significance level of 0.05. It is recommended that prior to the selection of ICB and QCBS as procurement methods for goods, works and services consideration should be given to project completion time, risk avoidance, contract funding arrangement and quality of services.Item Open Access Prediction and optimization of compressive strength of concrete containing nanosized cassava peel ash using artificial neural network(Federal University of Technology, Owerri, 2024-02) Nwa-David, Chidoebere DavidIn this work, artificial neural network (ANN) was adopted for optimization of the compressive strength of concrete containing nano-sized cassava peel ash (NCPA) as partial replacement ofcement. Levernberg-Marquardt back propagation and sigmoid function were employed in the model formulation. A total of four hundred (400) data set were presented to the network. Two hundred and forty (240) were used for training, sixty (60) were used for validation, and another sixty (60) were used for testing the network's performance. After training the network, the output and targets have an R - value of 0.99909 which is equivalent to 1. This indicates that the data used for training the network, have a good fit. Data used for this formulation were obtained experimentally. From the laboratory study, maximum compressive strength of 18.70 N/mm2 ,22.10 N/mm2 , 24.20 N/mm2, 30.10 N/mm2, 33.30 N/mm2 and 36.90 N/mm2 was achieved at a water-cement ratio of 0.75 at 19.5% replacement for 7, 14, 28, 56, 90 and 150 days curing age respectively while the corresponding ANN modelled maximum strength were 17.92 N/mm2, 22.24 N/mm2 , 24.34 N/mm2 , 30.50 N/mm2 ,33.23 N/mm2 and 36.85 N/mm2 . The predicted values were very much close to the experimental results. However, it was deduced that the replacement of cement with NCPA must not exceed 20%, if NCPA-concrete is to be used as a structural material. Evaluating the adequacy of the network with student’s T-test at 95% confidence level, proved that the model is worthy of adoption for reliable, time-effective and accurate strength-optimization of nanosized concrete.Item Open Access Analysis of risks in Nigeria ship building industry(Federal University of Technology, Owerri, 2024-03) Anyanwu, NnamdiThe aim of the study was to determine the determinant risks of occupational injury and illness associated with exposure to hazards in the shipbuilding and repair sector in Nigeria. The study used Starzs shipyard Onne, Rivers shipbuilding and repair clusters and Niger Dock shipbuilding facility in Lagos clusters and adopted a mixed research design approach in which both secondary data from the Environmental Health and Safety Department of the Shipyard and the primary data from survey were used. The method of principal component analysis , Risks analysis methods, and descriptive statistics cum inferential statistics were used to analyze the data obtained. It was found that, welding and cutting hazards, chemical fumes and dust inhalation hazards, and noise hazards with Eigen value for each exceeding 1(Eigen value>1), constitute the determinant hazards of Starzs shipbuilding and repair facility in Rivers clusters in Nigeria while in Niger Dock Shipbuilding facility Lagos clusters, risk of hazards associated with welding fabrication and cutting, noise hazards, chemical fumes and metallic particles inhalation, hazards linked to vibration of equipment and hazards linked to fire and explosion each have Eigen value greater than 1(Eigen value>1), as a result formed the determinant hazards in the Niger Dock Shipbuilding and repair facility to which worker are exposed. The workers in Niger Dock are further significantly exposed to fire and explosion hazards and hazards linked to vibration of equipment in addition to the three hazard types (welding and fabrication hazards, noise hazards and chemical fumes and dust particles inhalation risks) to which workers in Starzs Marine Shipyard are significantly exposed. The implication is that dock workers in Niger Dock are exposed significantly to greater number of occupational hazard types than those in Starzs Marine Shipyard, implying that workers in the shipbuilding and repair sector in Nigeria are exposed to similar hazard types, but significance or proportion of exposure to each hazard type is a function of the shipyard. The findings of the study also indicate that burns injury, rhinorrhea illness, cuts injury and tinnitus illness pose the greatest levels of risk of occurrence in Niger Dock. The result also indicates that about 42.1% of the dockworkers identified the existence of fall hazards (slips and trips hazards) in the shipbuilding sector in Nigeria while 77.3% of the respondents identified that dockworkers are exposed to electrical hazards in the shipbuilding and repair sector in Nigeria. About 62.5%, 83%, 26.1%, 99.8%, 52.3%, and 84.1% of the respondents identified that dockworkers in the shipbuilding and repair sector are exposed to vibration hazards, noise hazards, biological hazards, welding & cutting hazards, fire & explosion hazards, chemical fumes and dust hazards respectively. The implication of this is that the shipyard and the shipbuilding and repair sector in Nigeria should prioritize the control reduction and elimination of the occupational injury and illness types that pose the greatest risk of occurrence and consequences in Nigeria.Item Open Access Chemical inhibition of β-galactosidase activities and development of new protocols for β-galactosidase activity assay in microbial cell(Federal University of Technology, Owerri, 2025) Nwagwu, Oluchukwu RoselineInhibitory effects of surfactants, organic solvents and solvent mixtures on cell-free and cell-bound β-galactosidases were assessed to establish their sub-inhibitory concentrations for the development of methods for cell permeabilization and rapid in situ determination of β-galactosidase activity in Escherichia coli and Kluyveromyces marxianus. The concentration-response relationships of the individual surfactants, solvents and mixtures were fitted to a Gormpertz model to estimate the median inhibitory concentrations (EC50) and No-Observable-Effect-Concentration (NOEC) thresholds. The inhibitory effects of solvents on cell-free β-galactosidase were in the order: N, Ndimethylformamide (DMF) > dimethylsulfoxide (DMSO) > ethanol (E. coli) and DMF > DMSO ≥ ethanol (K. marxianus). The inhibitory effects of surfactants on cell-free β-galactosidases were in the order: 1-cetylpyridinium chloride (CPC) > Cetyltrimethylammonium bromide (CTAB) > sodium dodecyl sulphate (SDS). Triton X-100, sarcosyl, Tween 20, Tween 80 and sodium deoxycholate (SDC) are not inhibitory to β-galactosidases. The established range of concentrations of these permeabilizing agents that are not inhibitory were used for whole cell β-galactosidase activity assay in E. coli and K. marxianus. In this in situ β-galactosidase activity assay, the cells were not washed, and permeabilization agents remained integral part of the reaction mixtures. Some of the selected concentrations of permeabilizing agents used for both organisms were compared with the classical methods in the literature. For E. coli, assay with a 5% 9:1 ethanolchloroform mixture and 0.0008% CPC resulted in higher β-galactosidase activity than Miller’s SDS-chloroform treatment. For K. marxianus, the β-galactosidase activity with 0.15% sarcosyl, 0.4% SDC and 15% of 9:1 ethanol-chloroform mixture resulted in higher β-galactosidase activity than Kippert’s 0.133% sarcosyl treatment. This current method was found to be less timeconsuming and accurate. The treatments could be used as an alternative procedure for in situ assay of β-galactosidase activity in E. coli and K. marxianus cells.Item Unknown Prediction of re-aeration coefficient of rivers streamflow characteristics(Federal University of Technology, Owerri, 2023) Chimezie, Udochi IjeomaIn this study, a new model, designated as the N-Model, was developed to predict the re-aeration coefficient of rivers using streamflow characteristics. Re-aeration is an important phenomenon that sustains dissolved oxygen levels in receiving waters to support aquatic life and natural selfpurification of streams and rivers. Development of the N-Model was done for the sole purpose of getting a more accurate model that could easily be applied with no heavy laboratory work in order to be put into application on site. The performance of the N-Model is compared against various existing empirical models like O'Connor, Parkhurst, Churchill, Krenkel, Thackston, and Owen. Data collection was done from the following rivers: Otammiri, Kaduna, Adada, Oshika lake and Atuwara. Using O'Connor's model, the re-aeration coefficient of the Otammiri River was found to be 0.0753 with a very high correlation coefficient of 99.2%. The N-Model predicted the value for Otammiri River to be 0.076 with an accuracy of 98.4%. This was determined by comparing the predicted value of the N-Model with observed data, where the minimal difference between the two (0.076 vs. 0.075) indicated that the model was highly effective in estimating the re-aeration coefficient. The model by Parkhurst produced a coefficient of 0.078 while other models like the ones by Churchill and Owen showed much higher discrepancies with percentage errors of over 70%. Across all rivers, the N-Model demonstrated strong predictive accuracy, with an overall correlation coefficient of 98.9% and a low standard error of less than 4%. However, other models like Churchill and Krenkel give very small correlation coefficients often less than 25%, indicating that the N-Model offers a reliable and efficient alternative for estimating re-aeration coefficients from streamflow characteristics in varying environments.Item Unknown Study examining attitudes and perceptions of public health students at Imo State University, Nigeria towards virtual learning system(Federal University of Technology, Owerri, 2025) Iwunze, Chidera JudithAccording to Lokie (2021), virtual learning encompasses education that occurs beyond conventional classroom environments and broadens the use of technological resources, platforms, satellite connections, and similar technologies to access, analyze, create, share, and utilize data, information, and knowledge in manners that were almost unimaginable until very recently. Through virtual learning, students engage with a curriculum rooted in digital content, instructed by teachers who provide lessons online through video or audio. The Nigerian government has committed to boosting its citizens' ICT (information and communications technology) skills and bridging the digital divide. The Aim of this study was to determine the attitude and perception towards virtual learning system among public health students of Imo State University, Owerri, Imo State. The study employed a survey method that was descriptive in nature. The site of the study was Imo State University located in Owerri, Imo State, Nigeria. The study's population consisted of approximately 1,351 public health students from IMSU in Owerri, Imo State, who were enrolled in 100, 200, 300, and 400 level programs. The sample size consisted of three hundred and forty students (340), selected through a sampling procedure. Quantitative data were collected using a semistructured, self-administered questionnaire to address the four research topics of the study. Experts from the Public Health Department of IMSU established the authenticity of both face and content. After determining the reliability through the test-retest method, a reliability index of 0.83 was found. The obtained data was analyzed using a quantitative approach with the Statistical Package for Social Sciences (SPSS) (version 21.0). For the analysis of data, statistical methods used included frequency, percentages, mean standard deviation, and t-test statistics. According to the results, 137 respondents (90.7%) had taken part in a virtual classroom setting and held a positive view of the virtual learning approach. Furthermore, the outcome demonstrates that the participants' attitudes towards the virtual learning system are favorable. According to the study's conclusions, public health organizations’ and other health sector stakeholders should constantly More virtual learning systems should be incorporated into their programs; a range of virtual learning systems, such as online learning, virtual reality, and augmented reality; faculty and student support and training for effective use of these systems; and an assessment of the systems' efficacy to make sure they are fulfilling the needs of students. Among other things, they need to make virtual learningItem Unknown Design and simulation of kalman filter for estimation of gas turbine inlet temperature(Federal University of Technology, Owerri, 2024) Usen, Francis FrancisThe measurement of Gas Turbine (GT) Inlet Temperature remains a significant challenge for engineers, particularly in developing countries, due to the specialized technology required for accurate estimation and covariance noise signal attenuation in remote temperature measurement systems. This technology is primarily utilized by Gas Turbine manufacturers, who employ proprietary, closed-source mathematical models that are inaccessible to external engineers. To address this limitation, the present study develops an open-source model capable of both estimating GT Inlet Temperature and mitigating noise characteristics in the measurement data. The approach is based on the integration of a Kalman Filter (KF) model and a Plant model within a State-Space framework, utilizing real-time input parameters from two identical Gas Turbines, GT11 and GT12, designed by Asea Brown Boveri (ABB). The primary objective is to ensure that the proposed open-source model delivers optimal performance and solution accuracy comparable to that of the closed-source proprietary models. Initially, the Burner Can Temperature Rise Equation is employed to compute the GT Inlet Temperatures directly for the two turbine models. This equation is subsequently used to derive the system matrices in the State-Space representation, which describe the plant model. To complete the modelling, fictitious noise signals are introduced into the plant model and superimposed onto the Kalman Filter model to simulate real-world measurement conditions. The resulting design is implemented and tested in the MATLAB Simulink environment. Simulation results demonstrate that the proposed open-source model achieves accuracies of 98.1% and 97.2% for GT11 and GT12 respectively, when compared to real-time process data from ABB, while the calculated values yield 80% and 65% accuracies, respectively. Furthermore, the fictitious covariance noise signals were successfully filtered from the temperature measurements, confirming the robustness of the proposed model in mitigating noise and enhancing temperature estimation accuracy.Item Unknown Anticorrosion performance of chrysophyllum albidum and a synthetic inhibitor in simulated drilling fluid(Federal University of Technology, Owerri, 2019-09) Achinihu, Ikechukwu O.The anti-corrosive performance of ethanol extracts of Chrysophyllum albidum and a synthetic inhibitor was investigated using weight loss and potentiodynamic polarization technique on mild steel. Results from weight loss analysis revealed that inhibition efficiency increased with increase in concentration of the inhibitors while corrosion rate decreased with increase in concentration of the inhibitors due to the adsorption of the organic molecules on the metal surface. Highest inhibition efficiency of 96.6% at 218.2 ml/L was recorded after five days for the ethanol extracts of Chrysophyllum albidum and 96.05% at 250ml/L after three days for the synthetic inhibitor both in a simulated drilling fluid. Temperature studies carried out also revealed the efficacy of the ethanol extracts of Chrysophyllum albidumas compared to the synthetic inhibitor at the temperature ranges of 313K and 333 K. From the values of activation energy obtained, the mechanism of the adsorption process was proposed to be predominantly of chemisorption for both inhibitors. The values ofΔG obtained were all negative which reveals spontaneity of the process while ΔHads reveals endothermic reactions for both inhibitors in the simulated drilling fluid medium. Potentiodynamic polarization results showed that both the anodic and cathodic reactions were inhibited indicating that the inhibitors are of mixed type. The experimental data obtained fits well with Langmuir adsorption isotherm indicating that the inhibitors were adsorbed uniformly on the metal surface.Item Unknown Investigation of thermodynamic properties of liquid binary alloys(Federal University of Technology, Owerri, 2019-11) Adedipe, Adedayo MayowaA complex formation model has been used to study the thermodynamic properties of Bi-Sb at 1200k, Bi-Sn at 905k and Sb-Sn at 600k binary liquid alloys. The research reveals that Bi-Sb and Sb-Sn alloys are weakly ordered systems and compound forming liquid alloys (hetero-coordinated) i.e., unlike atoms of Bi-Sb and Sb-Sn pairing as nearest neighbors, while Bi-Sn is not a compound forming alloy but exhibit phase segregation (homocoordinated) i.e., like atoms of Bi-Sn pairing as nearest neighbors. The fitted and experimental values of the free energy of mixing of the three alloys compare well with each other at the temperature of interest. The value of 𝑔⁄𝑅𝑇 (a measure of the formation of a complex in each alloy) in Bi-Sb and Sb-Sn are greater than zero, which shows that none of the two alloys has a strong tendency to form complexes, while the value for Bi-Sn is less than zero. The values of the Gibbs free energy of mixing, 𝐺𝑀⁄𝑅𝑇 for Bi-Sb, Bi-Sn and Sb-Sn are found to be negative at all concentrations with a maximum value of -0.907, -0.640 and 0.926 respectively and are all symmetry at equiatomic composition (i.e c = 0.5). The concentrationconcentration fluctuation 𝑆𝐶(0) values for both Bi-Sb and Sb-Sn are less than the 𝑆𝐶𝐶 ideal (𝑆𝑐𝑐 𝑖𝑑(0)) values with a maximum value of 0.174 at c = 0.4 and 0.172 at c = 0.5 which justify that they are compound forming alloys. While BiSn 𝑆𝐶(0) exhibits a maximum value of 0.289 at c = 0.5, and greater than the ideal value and exhibited phase separation. Bi-Sb and SbSn shows negative and minimum values for Warren-Cowley short-range order parameter 𝛼1 as 𝛼1 𝑚𝑖𝑛 = −0.0391 at c= 0.6 and 0.0391 at c = 0.5 respectively, these value is quite small compared to the value of 𝛼1 for a complete ordering which is 𝛼1 𝑚𝑖𝑛 = −1.0 and this implies a tendency towards clustering and indicates a weakly pronounced hetero-coordination. Bi-Sn exhibited a maximum value for Warren-Cowley shortrange order parameter 𝛼1 as 𝛼1 𝑚𝑎𝑥 = 0.0680, this value is quite big compared to the value of 𝛼1 for complete order which is 1 𝑚𝑖𝑛 = −1.0, this implies a high tendency towards segregation and indicates a strong pronounced homocoordination. In addition, it is observed that computed values and experimental values of this quantity are in very good agreement both in BiSb, Bi-Sn and Sb-Sn alloys. From the thermodynamic properties, Bi-Sb and Sb-Sn are more suitable to be used as solders than Bi-Sn because they are compound forming alloys.Item Unknown Modelling the effects of local food spices on the growth of Escherichia coli 0157:H7 and Campylobacter sp.(Federal University of Technology, Owerri, 2018-11) Adeleye, Samuel AdeniyiThe activity of food spices (pepper, ginger and salt) were investigated for their ability of inhibit or stimulate the growth of Campylobacter jejuni and Escherichia coli 0157:H7, isolated from meat and coleslaw samples, in singles and in combination. In addition, the isolates were subjected to temperature dependent inactivation for the development of primary models using the GinaFit Software. A 2 k Factorial plot was carried out to determine the single and combined effect of the spices on the test isolates. Results shows that at a concentration of 800 µg/ml, ginger extracts had stationary/inhibitory effect and pepper had inhibitory effects while salt also had inhibitory effects at 4% concentration. At 8% concentration, results indicated a bactericidal effect as the mean growth declined rapidly below the initial bacterial population. Similar results was also recorded for ginger at 120µg/ml. However, pepper had stimulatory effect on Campylobacter jejuni. On the other hand, results on Escherichia coli 0157:H7 shows that the pepper extracts had mean stimulatory effect at 400 µg/ml, while the salt extracts had similar results at 4% salt concentration. Mean inhibitory effect was obtained for ginger extracts at 400 µg/ml and 800 µg/ml but, stimulatory at 1200 µg/ml. Also, at a concentration of 800 µg/ml, pepper extracts had inhibitory effects, while salt solution also had stimulatory effects at 8% concentration. At 12% salt concentration, the effect on mean growth was bactericidal demonstrated by rapid decline below the initial bacterial population. GINAFIT Models were used to determine values of “Α, δ1, Ρ, Log N, Kmax, R2 , MSE” which were adopted for model development. Findings had it that at -4 and 4 degrees, the isolates was inactivated. In addition, Campylobacter jejuni tested grew at 25 and 35 degrees while Escherichia coli grew at 25, 35 and 45 degrees but inactivated at -4 degrees.Item Open Access Assessment of common ambient air pollutants and respiratory health problems among road construction workers in Imo State, Nigeria(Federal University of Technology, Owerri, 2025) Bwala, John MarkRoad construction workers are exposed to air pollutants which can cause respiratory health problems. The general objective of this study is to assess the respiratory health problems among road construction workers in Imo state, Nigeria. This research was a cross sectional study of Road construction workers in Imo state, Nigeria. The multistage sampling technique was used to select 353 subjects from the 3 senatorial zones of Imo State. At the construction sites, gas meters were used to measure gas levels at strategic points. The blood pressure, pulse rate and forced vital capacity readings of the subjects were taken by well-qualified health personnel. The mean CO, SO2 and SPM levels at Imo West was 182.40±6.41ppm, 516.24±55.03μg/m3 and 1956.22±30.75μg/m3 respectively. The mean CO, SO2 and SPM levels at Imo East was 185.34±6.46ppm, 518.26±55.12μg/m3 and 1960.17±30.79μg/m3 respectively. The mean CO, SO2 and SPM levels at Imo North was 187.51±6.49ppm, 520.14±55.34μg/m3 and 1956.68±30.25μg/m3 respectively. In all the senatorial zones, SPSS data analysis using the oneway ANOVA at 0.05 level of significance showed that the levels of CO, SO2 and SPM was significantly higher (P<0.05) than safe levels. The mean Forced Vital Capacity among all the workers in Imo West, Imo East and Imo North was 2263.34±482.33, 2578.80±751.80, and 2382.78±610.42 respectively. The major respiratory health problems among the road construction workers in Imo state include coughing 211 (59.77%); sneezing, 290(82.15%); catarrh, 79(22.38%); sore throat, 72(20.39%); asthma, 29(8.22%); short breadth, 121(34.28%); pneumonia, 66(18.70%); headache, 133(37.68%); and wheezing, 170(48.16%). Road construction workers were advised to always wear their personal protective equipment, especially the nose mask during construction work to prevent respiratory health problems.Item Open Access Some deductions from the factorization of finite simple groups(Federal University of Technology, Owerri, 2017-07) Agigor-Mike, Precious UgonwanyiThis work looked into the factorization of minimal normal subgroups of innately transitive groups. It was shown that if , is a finite set of primes and if M is a non-abelian characteristically simple group with simple normal subgroups and ( * +) is a full factorization of M then (i) the pair ( * ( ) ( )+) forms -groups (ii) the subgroups ( ) and ( ) cannot have normal -complements in and that ( ) and ( ) are not - complements of each other. Again from the results of Baddeley and Praeger it showed that and are full diagonal subgroups of M. If and are self normalizing subgroups in M and not isomorphic to ( ) , ( ) , ( ), then and are maximal nilpotent subgroups of M. Further, and are conjugates and therefore solvable groups. It further showed that if G is a finite simple group with a transitive minimal normal subgroup M where M is characteristically simple and can be expressed as and if and are proper subgroups of M, then ( * +) is a full factorization such that for all , the pair ( * ( ) ( )+) is a full factorization and ( ) and ( ) are conjugates * +, ( ) * + and ( ) ( ) ( ) * +Item Open Access Optimization of aluminium sheet production in a distressed economy(Federal University of Technology, Owerri, 2024-10) Nnabude, MichaelThis research deals with the optimization of aluminum sheet production in a distressed economy. The aluminum roofing sheet industry plays a pivotal role in the construction sector due to the inherent advantages of aluminum roofing sheets including corrosion resistance, lightweight properties and recyclability. Operational inefficiency results in higher production costs and operational delays. The methods applied in this study includes data collection through questionnaires and the company record books. Data analysis using Excel and Python were used to identify trends and pattern in machine failure and this helped in understanding the factors contributing to decline in productivity. Strategic maintenance initiative including Lean manufacturing tools like Heijunka and Takt Time were used to facilitate increase in production while application of predictive maintenance through regression model were used to reduced average machine downtime thereby increasing the operational efficiency. From the result obtained, the Analysis of production data from 2017 to 2021 shows operational inefficiencies and external disruptions, such as machine downtime and pandemic-related constraints, which collectively contributed to a 28.8% decline in total production and a 20% reduction in production targets over the period. The application of predictive maintenance through regression models demonstrated a substantial improvement in operational efficiency, notably reducing average machine downtime by 55.3% from 1,316.67 hours in 2021 to 588.34 hours in 2023. In addition, strategic maintenance initiatives, including lean manufacturing tools like Heijunka and Takt Time, facilitated a 56.2% increase in total production from 3,170 tons to 4,950 tons between 2017-2021 and 2022-2023 periods, respectively. This enhancement not only optimized production schedules but also aligned production rates more closely with market demand, resulting in a 30.4% improvement in net revenue generation after expenses. Cost management strategies further stabilized machine maintenance costs around the benchmark figure of ₦6,000,000 in 2022-2023, showcasing effective financial control amid economic uncertainties.Item Open Access Formulation of matlab based computer program for mixture experiments, using Osadebe's regression model(Federal University of Technology, Owerri, 2020-01) Agwuocha, Ifeanyi M.This work “Formulation of a matlab based computer program for mixture experiments, using Osadebe’s regression model” formulated a computer program for analysing mixture experiments based on the Osadebe’s regression model. The computer program developed on Matlab (2015) was called MIX-PRE. It comprises five graphical user interfaces and they are; about user interface, model predicting user interface, model validation user interface, graph validation user interface and the result user interface. The predicting ability of MIX-PRE was tested by comparing results obtained from it to those from previous studies on Osadebe’s Regression model carried out by Anya in 2015 and Okere in 2014. The percentage difference between the results from MIX-PRE and from the previous studies generally showed a less than 4% variation in the results. The highest and lowest values of the percentage differences obtained for the coefficient of regression between MIX-PRE and Anya were 1.79% and -1.43% respectively. While, that between MIX-PRE and Okere were 1.95% and -0.92% respectively. Statistical F and T-tests were used to validate MIX-PRE. The percentage difference in the F values between results obtained from Anya and Okere were respectively compared to that generated by MIX-PRE and their values were 0.02056% and 0.004826%. Similarly, T values obtained from the works of the two authors were compared to that of MIX-PRE and the percentage difference obtained were 0.0001664% for Anya and 0.003733% for Okere. The accuracy of MIX-PRE was further tested using results obtained from experiments carried outin the laboratory. In the second part of this study, a laboratory experiment to determine the compressive strength of concrete using red lump stone as coarse aggregate was carried out. A total of 45 cubes of size 150mm were produced in the laboratory from ten (10) randomly selected mix-ratios. Optimum compressive strength obtained after 28 days of curing by immersion was 20.33N/mm2 and the corresponding mix ratio was 0.657:1.00:0.914:2.286 (water: cement: river sharp sand: red lump stone). F and T-tests at 95% confidence level were then used to test the adequacy of the model predicting ability. F and T values calculated were 1.00293 and 1.735 respectively. While, F and T values from the statistical tables were 9.1172 and 2.7765 respectively. Since the values obtained from calculations were all less than that from the tables, the null hypothesis was accepted, that is, the model showed no significant difference between the experimental results and model prediction. Anova test was also used to further validate MIX-PRE. An anova calculated value of 67.748 from MIX-PRE was found to be greater than the statistical table F value of 17.4434. Therefore, the formulated program (MIX-PRE) will be of great importance in the reduction of the time and resources needed in meeting up with the requirement of the mix design process in concrete production since, there will no longer be the need for trial mix designs in the laboratory.Item Open Access An assessment of social crisis arising from water pollution in Gbaramatu region of Delta State(Federal University of Technology, Owerri, 2021-06) Olaye, Precious AreremiThe research was focused on water pollution induced by social crises, water samples were collected and analyzed using four communities in Gbaramatu region in Delta State as a case study. The goal was to examine the role of social crises and as regards to water pollution in the study area. Methodology involved collection of water samples from different locations to determine the quality of the water in four communities under study. Three of the sites are impacted or polluted areas while the fourth is the control site with less history of social crises. Results shows that most of the impacted environment reveals adverse pollution in the waters. Targeted parameters include; Temperature, which ranged between (27 – 28 οC), pH level, range from 4.1- 5.5), Total Dissolved Solid in water (TDS), range 1938 (300)Mg/l, Turbidity 60.0 (NTU), Salinity 1400 (600)CL, Total Organic Carbon in soil 0.84-0.74(mg/kg), BOD 2.14 (4.0-10.00)mg/l, COD 320 (10.0)mg/l Total Hydrocarbon Content. (THC) 784 (10.0) mg/l, Oil and Grease Content 1246 (10.0-20.0)mg/l. The determination of heavy metal concentrations were carried out with a wide digestive hot plate for heavy metals analysis. The concentrations exceeded the Federal Ministry of Environment Standards of Safe Environmental. Overall results showed pollution impact within study area and were statistically presented in Histogram and they reveal adverse environmental impact. Recommendations were suggested to promote safe environmental ethnic, tolerance and peaceful co-existence in order to minimize social crises posed pollution in study area.