Department of Chemical Engineering
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Item BMFA: A Blockchain Framework for Secure and Scalable Multifactor Authentication(Scientific Journal of Engineering, and Technology (SJET), 2025) Asheshemi, Nelson Oghenekevwe; Okoro Akpohrobaro Daniel; Elohor, Ayeh Blessing; Ifioko, Ayo Michael; Atuduhor oghenerukevwe ReghaThis paper introduces a Blockchain-based Multifactor Authentication (BMFA) layering which would enrich data privacy, confidentiality and security of digital systems. The presented framework merges blockchain, its decentralised and immutable ledger and multifactor authentication, which embraces the combination of possession, knowledge, inherence, and behavioural factors. With asymmetric cryptography and smart contracts, the framework provides tamper-resistant, scalable, and auditable processes of authentication. Through computational simulations in this paper, it is revealed that the BMFA framework is much more efficient than the traditional multifactor authentication (TMFA) systems. The most significant results are that the authentication token entropy increased by 45 per cent, tolerance probability against the adversary went down by 60 per cent, and the mean authentication latency is 30 milliseconds, which is still within the bounds of practical use. Moreover, statistical analysis also indicates that the BMFA framework enhances authentication token randomness and reduces the dependencies between two authentication events, thus helping alleviate token prediction and replay attacks. The scalability evaluation reveals that optimised blockchain designs enable the BMFA system to handle growing levels of users without affecting the performance. Altogether, this study confirms the practicality of using a combination of blockchain technology and multifactor authentication to establish an efficient, secure, and reliable structure that can help to overcome modern complexity in a digital context in regard to cybersecurity.Item Evaluation and Adsorption Modeling of Continuous Adsorption of Malachite Green Pigments onto Sawdustderived Activated Carbon in a Fixed Bed Column(International Journal of Engineering Research and Technology, 2025) AKAKABOTA, A. O; OHIMOR, E. O; ISIAKPERE, PRECIOUSThe study was conducted to investigate the adsorption of malachite green dye onto activated carbon prepared from sawdust in a fixed-bed column, with the aim of understanding the process dynamics and improving pollutant removal efficiency. The prepared activated carbon was characterized by Scanning Electron Microscopy with Energy Dispersive X-ray Spectroscopy (SEM-EDS), Fourier Transform Infrared Spectroscopy (FTIR), and Brunauer-Emmett-Teller (BET) surface area analysis. The column performances were evaluated by varying bed heights (1.25, 2.5, and 5.0 cm) while keeping other factors such as influent flow rate (5 ml/min) and concentration (500 mg/L) constant to obtain experimental breakthrough curves. From the breakthrough curves, it was observed that the breakthrough time, tb, increased from 180 mins to 270 and 330 mins for bed heights of 1.25, 2.5, and 5 cm, respectively. The exhaustion time (td) for the adsorbent bed was found to increase from 390 mins to 420 mins and 510 mins as bed height increased from 1.25 to 2.5 and 5 cm, respectively. The adsorption capacity, qo, was found to be 221.54, 148.34, and 91.22 mg/g for bed heights of 1.25, 2.5, and 5 cm, respectively. The removal efficiency of malachite green was found to be 54.53%, 67%, and 68.82% for bed heights of 1.25, 2.5, and 5 cm, respectively. The performance of the column was analyzed using the Thomas, Adams-Bohart, and Yoon-Nelson models. The rate constant for all three models decreased with increasing bed heights, while the time required for 50% adsorbate breakthrough increased with increasing bed height. The Adams-Bohart model, which presented consistently high R² values within the range of 0.8344 to 0.9229, is the most suitable model for describing the experimental data.Item Fire and Explosion Consequence Analysis of Occupied Buildings in an Lpg Storage Facility in Southern Nigeria(Advanced Journal of Science, Technology and Engineering, 2022) Olayebi, Oluwafemi; Ayanleke, PatrickThe purpose of this work was to carry out an evaluation of occupied buildings from the devastating impact of an explosion in a Liquefied Petroleum Gas (LPG) bulk storage facility with the intention to provide information on blast requirements of the buildings and make layout modification as needed using the consequence-based approach. The simulation was done using DNV’s Process Hazard Analysis Software Tool (PHAST) and the process data were obtained from a process plant located in the Niger-Delta region of Nigeria. Three major scenarios; catastrophic rupture, full bore rupture was considered for a 6-inch pipe and fixed duration release of the stored LPG and propane gas using the TNO multi-energy method to determine the Maximum Credible Event on the occupied buildings within the facility From the study, the catastrophic rupture of LPG vessel #18 at 2/F weather category gave the worst impact with an overpressure effect of 0.7barg at a hazard distance of 166.959m. The thermal radiation intensity of 37.5KW/m2 due to Jet fire from the fixed duration release of Propane vessel #22 at 2/F weather category was found to produce the greatest consequence/impact at a hazard distance of 180.72m. The results from this work show that most of the occupied buildings within the location are in the vicinity of the effect zone of both explosion overpressure and Jet fire thermal radiation.Item Methylene Blue and Iron (Ii) Adsorption onto Raphia Hookeri Seed: A Comparative Equilibrium Isotherm Study(International Journal of Chemical and Process Engineering Research, 2021) Tarbuka, P. F.; Gumus, R. H.In this study, activated carbon prepared from Raphia hookeri seed was employed as an adsorbent to take up methylene blue (an organic ion-in-solution) and iron (II), a metal ion-in-solution. The biosorbent was prepared using chemical activation using sodium hydroxide (NaOH) as an impregnating agent. Calibration was performed with a focus on the change in the adsorbate concentration. The equilibrium isotherms study was conducted by considering a range of sorbate concentrations, to determine the optimal conditions for the adsorption systems. The same sorbate volume (10 ml), and the same dosage (0.3g) of biosorbent were used for both adsorption processes. Linear analysis was used to compare the best-fitting isotherms. Langmuir, Freundlich, and Dubinin-Radushkevich models were tested. The highest coefficient of determination values (R2 ) for both iron (II) and Methylene blue was obtained from the Langmuir isotherm as 0.9266 and 0.9572, respectively, compared to values from the other isotherms tested – indicative of Langmuir isotherm’s superior fit. Estimated values of ‘separation factor’, KR, for Methylene blue (0.29457), however, was lower than that of iron (II) (0.42141) - an indication that the sorbent treats methylene blue better than iron (II), though both processes are feasible.Item Process Intensification of Colemanite Leaching Using Sulfuric Acid in a Batch Reactor(International Journal of Engineering Research and General Science, 2016) OLAYEBI, Oluwafemi O.; OLUFEMI, Ademola S.; AZEEZ, Mayowa A.This contribution investigated methods of intensifying the leaching of colemanite using sulphuric acid for the improvement of boric acid recovery. Boric acid is one of the most commonly used boron compounds produced by dissolving colemanite (2CaO⋅3B2O3⋅5H2O) in aqueous sulfuric acid which results in the formation of gypsum (CaSO4⋅2H2O) as a by-product and must be separated from the main product. The dissolution of colemanite gives the amount of boric acid formed; the purity and crystallization of boric acid are affected by filtration of gypsum. In this study, and the factors that were examined in this study were stirrer agitation speed, particle size, reaction temperature on the dissolution of colemanite in the reaction of boric acid production. Colemanite having the same elemental chemical composition and particle size, sulfuric acid and distilled water were used as reactants for the boric acid production reaction in this study. The crushing of the colemanites were one in a jaw crusher, ground in a hammer mill and then sieved. The biggest diameter of the colemanite minerals was 150 μm and the experiments were performed at different particle sizes of colemanite (0-150, 0-250 and 250-1000 μm), temperatures (70- 90 °C) and stirring speed (350-500 rpm). The results obtained, showed that increasing the acid concentration results in a significant increase boric acid recovery. The highest recovery was obtained at 85 °C temperature. Increasing the mixing speed form 350 rpm to 500 rpm increased the recovery by 5.5%. Thus, the increase in agitating speed from 350 to 500 rpm resulted in a significant increase in boric acid recovery. Thus, it was concluded that agitation have a significant effect on boric acid recovery above 500 rpm. The batch process proved to be better than the semi-batch process in terms of the amount of boric acid recovered.Item Production of biodiesel from palm kernel oil (PKO) using sodium-ethoxide: The effect of time(International Journal of Research in Engineering and Innovation (IJREI), 2017) Tarbuka, P.F.; Ovonomo Onocha; Ohimor, E.O.In the production of biodiesel a wide variety of vegetable oils can be used as raw material. In this research palm kernel oil was used. The pure palm kernel oil could have been used as diesel but the viscosity would just be too high for application in engines and automobiles. In an attempt to modify (or improve on) the viscosity, transesterification was done with the aid of sodium-ethoxide; a blend of sodium hydroxide (NaOH) and ethanol (C2H6O). The effect of time on the yield and how it affects the viscosity of the PKObiodiesel so produced was investigated. The biodiesel obtained had a viscosity that was less than that of the original PKO by almost 80%. And results obtained from the runs indicate that the yield is nearly independent on reaction timeItem Production of Biogas from Co-Digestion of Cow Dung, Saw Dust and Maize Husk(Advances in Chemical Engineering and Science, 2018-08) Okewale, Akindele Oyetunde; Anih, Christiana Edward; Omoruwou, FelixThe co-digestion of cow dung, with maize husk for biogas production at laboratory scale was investigated. The study was carried out at a temperature range of 24˚C - 30˚C and pH range of 5.5 - 6.5 for a period of 60 days with a total solid concentration of 7.4% in the digester sample (fermentation slurry). Water displacement method was used to collect the biogas produced which was subsequently measured. 444.8 mL was the cumulative biogas yield at the end of 60 days retention time in the digester 1, which comprised of cow dung, maize husk, and water. Digester 2, which is made up of sawdust, cow dung, and water produced negligible biogas at the end of 60 days of the experiment. X-RF analysis revealed high presence of elements like silica, aluminium oxides, and aluminium oxides in cow dung, maize husk, and sawdust respectively. The preponderance of alkanes and methyl group inmaize husk makes it to produce biogas compared to saw dust as shown by the Fourier transform infrared spectroscopy (FTIR) that was carried out to identify the various functional groups. The potential of maize husk to produced biogas was also established. The kinetic modeling shows that there was an increase in biogas yield as the retention time increases as depicted by the linear modelItem Removal of Heavy Metals from Petroleum Refinery Effluent Using Coconut Shell- Effluent Using Coconut Shell-Based Activated Based Activated Carbon(CARD International Journal of Engineering and Emerging Scientific Discovery, 2017) Olayebi, O.O.; Adebayo, A. T.The performance evaluation of locally prepared activated carbon from coconut shell in removing Cr3+, Cu 2+, Pb2+ and Zn2+ions from Petroleum refinery effluent water was studied. The activated carbon produced was chemically activated utilizing Zinc chloride as activating agent. Batch Adsorption studies were carried out to examine the effect of adsorption dosage, contact time, pH and stirring speed on the adsorption ofCr3+, Cu 2+, Pb2+ and Zn2+from Petroleum refinery effluent water. In studying the effect of one factor others were kept constant. The adsorbent was contacted with the adsorbate for time intervals between 30 to 60 mins. The kinetic studies showed that pseudo – second –order reaction model best described the adsorption process, also the Langmuir adsorption isotherm best fit the adsorption data at equilibrium. Based on the results obtained, it can be concluded that Coconut based activated Carbon is a viable alternative for treating industrial effluent water.Item Simulation of Hydrate Formation and Prevention in Subsea Wells Using Unisim(INTERNATIONAL JOURNAL OF APPLIED & ADVANCED ENGINEERING RES., 2022) OLAYEBI, Oluwafemi; AKPERE, Handelhe oil and gas industry has been taking stringent measures to prevent the formation of hydrates which cause severe flow assurance issues due to pipe blockage, production loss and pose safety and environmental hazards due to pipe rupture and leakages. In this work the Process Simulation and Modeling software Unit Simulation (UNISIM) was used for the simulation of hydrate formation and prevention in subsea wells. To prevent the deposition of natural gas hydrate in subsea oil and gas wells, the hydrate formation area in wellbore must be predicted. The simulation results established methanol as a thermodynamic inhibitor and agree with literature as the 0%, 30% and 70% methanol injection composition respectively causes shifting to the left of the hydrate equilibrium curve reducing the hydrate formation areaItem Strategic Feature Selection for Enhanced Scorch Prediction in Flexible Polyurethane Form Manufacturing(Journal of Computing Theories and Application, 2024) Omoruwou, Felix; Ojug, Arnold Adimabua; Ilodigwe, Solomon EbukaThe occurrence of scorch during the production of flexible polyurethane is a significant issue that negatively impacts foam products' resilience and generally jeopardizes their integrity. The likelihood of foam product failure can be decreased by optimizing production variables based on machine learning algorithms used to predict the occurrence of scorch. Investigating technology is required because prevention is the best approach to dealing with this problem. Hence, machine learning algorithms were trained to predict the occurrence of scorch using the thermodynamic profile of polyurethane foam, which is made up of recorded production variables. A variety of heuristics algorithms were trained and assessed for how well they performed, namely XGBoost, Decision trees, Random Forest, K-nearest neighbors, Naive Bayes, Support Vector Machines, and Logistic Regression. The XGboost ensemble was found to perform best. It outperformed others with an accuracy of 98.3% (i.e., 0.983), followed by logistic regression, decision tree, random forest, K-nearest neighbors, and naïve Bayes, yielding a training accuracy of 88.1%, 66.7%, 84.2%, 87.5%, and 67.5% respectively. The XGBoost was finally used, yielding 2-distinct cases of non(occurrence) of scorch. Ensemble demonstrates that it is quite capable and is an effective way to predict the occurrence of scorch.Item Synthesis of improved dye-sensitized solar cell for renewable energy power generation(Elsevier Ltd, 2020) Okewale, A. Oyetunde; Jasper Ejovwokoghene Ikpesu; Iyuke, Sunny E.; Daramola, MichaelThe demand for cheap and affordable cost of fabrication and increased power conversion energy of DSSC has made most researchers sought for better ways to optimize individual parts of the cell to improve its efficiency. Thus, this paper reviews different ways to synthesize and fabricate an improved DSSC for renewable energy power generation. This article reviews the various fabrication techniques of FTO in DSSCs as well as incorporation of graphene for optimization of the DSSCs. Optimization of DSSC using FTO was reviewed with the various method of fabrication (Hydrothermal methods, CVD, Sputtering and Spray pyrolysis) for an effective light harvesting. Then, we discussed the application of graphene-based material into the various parts of the photoanode (transparent conducting electrode, semiconductor layer and dye molecules) as well as the counter electrode. Incorporating graphene into the photoanode as discussed can improve the efficiency of the cell due to its unique properties leading to a better dye absorption, improved charged separation, and excellent electrical conductivity thereby resulting in improved performance of the cell. Finally, an outlook for other trends in optimizing DSSCs was providedItem The Use of Rubber leaf Extract as a Corrosion Inhibitor for Mild Steel in Acidic Solution(International Journal of Materials and Chemistry, 2017) Okewale A. O.; Olaitan A.This work has explored the possibility of using plant extract as a corrosion inhibitor other than the use of conventional organic materials as corrosion inhibitor. Rubber leaf extract which contains the carbonyl groups, aromatic rings, and double bonds as indicated by the GCMS, phytochemical, and FTIR analysis is one of the good natural plant extract as corrosion inhibitor. Gravimetric method was used to determine the weight loss on surface of mild steel at various inhibitor concentrations in 0.1M HCl solution. The highest inhibition efficiency of 86% was achieved using the rubber leaf extract as inhibitor. Adsorption mechanism was investigated using Langmuir, Temkin, and Freundlich isotherms. Inhibitor adherence on the mild steel surface was spontaneous with the negative Gibb’s free energy value of -18.07kJ/mol obtained. The inhibitor was adsorbed on the mild steel surface through adsorption of the phytochemical components on the surface of mild steel which protects the metal surface from corroding. The corrosion rate decreases with increase in various inhibitor concentrations and exposure time studied.Item Unmasking effects of feature selection and SMOTE-Tomek in tree-based random forest for scorch occurrence detection(Bulletin of Electrical Engineering and Informatics, 2025) Omoruwou, Felix; Okpor, Margaret Dumebi; et. alScorch occurrence during the production of flexible polyurethane foam has been a menace that consistently, jeopardize a foam’s integrity and resilience. It leads to foam suppression and compactness integrity failure due to scorch. There is always the increased likelihood of scorching, and makes crucial the utilization of methods that seek to avert it. Studies predict that the formation of foam constituent processes via optimization using machine learning have adequately trained models to effectively identify scorch occurrence during the profiling in the polyurethane foam production. Our study utilizes the random forest (RF) ensemble with feature selection (FS) and data balancing technique to identify production predictors. Study yields accuracy of 0.9998 with F1-score of 0.9819. Model yields 2-distinct cases for (non)-occurrence of scorch respectively, and the ensemble demonstrates that it can effectively and efficiently predict the occurrence of scorch in the production of flexible polyurethane foam manufacturing process.