Yaba College of Technology
  • Lagos, Lagos, Nigeria
Recent publications
Background The use of nitrile compounds is usually high, particularly in chemical industries, which calls for serious concern because of their relevance to the environment. The essential role of nitrilases in the bioremediation of harmful nitriles from environmental wastes cannot be overemphasized. The study aimed to unveil the biodegradative potentials of bacterial strains associated with the degradation of nitrile pollutants. Methods Bacterial strains capable of utilizing glutaronitrile as the sole source of carbon and nitrogen were isolated from solid waste leachates by a selective enrichment culture technique. The test organisms were grown in mineral salts medium (MSM), and the metabolic products were determined using gas chromatography-flame ionization detection (GC-FID). The nitrilase gene was amplified by polymerase chain reaction (PCR) and by using appropriate primers. Results The growth studies showed that the test organisms grew on the two nitriles. The doubling times of 12.16 d and 9.46 d (specific growth rate, µ=0.082 d ⁻¹ , 0.106 d ⁻¹ ) were obtained for each pure culture of Bacillus sp. srain WOD8 and Corynebacterium sp. srain WOIS2 on glutaronitrile (as single substrate), respectively. While the same strains had doubling times of 11.11 d and 10.00 d (µ=0.090 d ⁻¹ , 0.100 d ⁻¹ ) on benzonitrile (as single substrate). However, the mixed culture (comprising the two strains) had doubling times of 7.40 d and 7.75 d (µ=0.135 d ⁻¹ , 0.129 d ⁻¹ ) on glutaronitrile (as single and mixed substrates), respectively. While doubling times of 8.09 d and 8.71 d (µ=0.124 d ⁻¹ , 0.115 d ⁻¹ ) were obtained for the same mixed culture on benzonitrile (as single and mixed substrates). Based on gas chromatographic analysis, the residual glutaronitrile concentrations at day 16 for strains WOD8 and WOIS2 were 35.77 g L ⁻¹ (72.2%) and 9.30 g L ⁻¹ (92.5%), respectively, whereas the residual benzonitrile concentrations for the same strains were 27.39 g L ⁻¹ (78.8%) and 13.79 g L ⁻¹ (89.2%), respectively. For the mixed culture, residual glutaronitrile and benzonitrile concentrations at day 16 were 13.40 g L ⁻¹ (88.5%) and 10.42 g L ⁻¹ (91.5%), respectively, whereas for the mixed substrates (glutaronitrile and benzonitrile), 7.21 g L ⁻¹ (91.7%) and 4.80 g L ⁻¹ (94.2%) of residual glutaronitrile and benzonitrile concentrations were obtained by the same consortium. The gene for nitrilase involved in nitrile degradation was detected in the genome of the bacterial strains. The amplified nitrilase gene gave PCR products of sizes 1400 bp and 1000 bp, as expected for strains WOD8 and WOIS2, respectively. 4-Cyanobutyric acid (4CBA), glutaric acid (GA), and benzoic acid (BA) were obtained as metabolites following nitrile degradation in vitro. Conclusion These results revealed that strains WOD8, WOIS2 and the mixed culture (consisting of the two strains) have proven to have the capacity to metabolize nitriles (glutaronitrile and benzonitrile) as the carbon and nitrogen sources. However, the mixed culture had higher nitrile degradation rate as compared to each pure culture of the two test organisms. These results also provide insight into the evolutionary genetic origin of a nitrilase gene that encodes an enzyme that catalyzes nitrile degradation in these strains. Hence, the bacterial strains that harbor this kind of gene may be used as promising biological agents for the remediation of sites polluted with nitriles, thereby opening new perspectives for encouraging data for a bioremediation bioprocess.
This study assessed the seasonal variation in the magnitude of marine litter along the Gulf of Guinea coastline, Araromi seaside, Nigeria with a survey of twenty sampling sites. The total number of litter items collected was 29,029 comprising 7358 and 21,671 items in the dry and rainy season respectively. The average number of items per square meter was higher in the rainy season (1.80 ± 0.35) than in the dry season (0.61 ± 0.19). Plastic materials dominated the litter composition with 86 % and 91.8 % in the dry and rainy season respectively. The beach cleanliness assessed as clean coast index (CCI) depicted the beach as dirty (12.26 ± 3.74) during the dry season and extremely dirty (36.13 ± 6.91) in the rainy season. The hazardous item index (HII) also showed the coastline was littered with hazardous items. These results provide baseline data for marine litter management along the Gulf of Guinea coastlines and other coastlines in Africa.
This paper discusses the influence on three Catholic churches in Lagos of the short-lived Oye-Ekiti Christian Art Workshop (1947-1954) and questions how the philosophy of the workshop and the artworks it produced are regarded today. The study traces the history of the Christian religion in Nigeria and the religious beliefs of the Nigerian people before the arrival of Christianity. It also examines the synthesis of traditional Yoruba art and the Christian religion introduced by the Oye-Ekiti, and interrogates the opposition of some church leaders in recent times to representations of Christian images in Yoruba indigenous forms. This opposition, which has led to the rejection and subsequent removal of artworks that formerly adorned the three Lagos churches is contextualized in interviews with the parish priests of these three churches. It is argued that Nigerian art is rich in signs and symbols due to its multi-ethnic, diverse culture and religious beliefs and proposes that the Oye-Ekiti Christian Art Workshop was necessary because it promoted indigenous art as a potential cultural vehicle for Christian liturgy in Nigeria.
Composites of water hyacinth fiber thermoset epoxy (WHE) composites were developed and characterized. Water hyacinth (WH) fibers were treated in an optimized 6% concentration of sodium hydroxide (NaOH) solution for an hour before composite fabrication by mixing with an epoxy resin (E) matrix. Fourier Transform Infrared (FTIR) and Field Emission Scanning Electron Microscopy (FE-SEM) analyses were conducted on both the treated water hyacinth (TWH) and untreated water hyacinth (WH) fibers, and the constituent composites. The mechanical properties (such as tensile, flexural, and impact) of the WHE composites were tested. The results obtained showed that treated water hyacinth epoxy composites (TWHE) provided better mechanical properties with remarkable improvement of up to 13%, 17%, and 7% for tensile, flexural, and impact strength, respectively, in comparison with untreated water hyacinth epoxy composites (WHE). FESEM results revealed strong fiber/matrix interfacial bonding between the treated fibers and epoxy matrix while the untreated WHE composites showed evidence of poor compatibility between the untreated WH fibers and the epoxy matrix, thus decreasing the mechanical properties of the composites. The results have demonstrated that water hyacinth fibers have the potential as an alternative material to replace synthetic fibers in composite applications.
This research aims to investigate the role of a new carbonizing agent (that is sepiolite) in the RPUF polymeric system's intumescent flame retardants (IFR) system, as well as the impact of sepiolite nanoclay on the morphology and flame resistance of the rigid PU foam polymeric system. This paper presents work on IFR formulation of ammonium polyphosphate (APP), sepiolite (SEP) and melamine (MEL) embedded in rigid polyurethane (foam RPUF). Rigid This research aims to investigate the role of sepiolite as a carbonizing agent in the RPUF polymeric system's intumescent flame retardants (IFR) system, as well as the impact of sepiolite nanoclay on the morphology and flame retardancy of the RPUF polymeric system. PU foam was prepared in a closed mould, and the amount of IFR constituents was varied in each foam formulation. The obtained foam was tested for its morphology and flame retardance. Scanning electron microscopy (SEM) revealed a fine, closed-cellular structure at 16phr IFR loading; increasing IFR content induced larger cell sizes with blowholes. Incorporating 16 and 20 phr IFR into RPUF increased the nanocomposites LOI values to 22.80 and 20.0 % respectively relative to pristine RPUF (18.00 %). The highest improvement in the LOI values for the nanocomposites was achieved at 16 phr IFR/RPUF compared to previous studies with 25 phr. The nanocomposites passed the UL-94 testing with a V-0 grade in comparison with neat RPUF that failed the test. These results affirm that IFRs of APP/SEP/MEL have changed the morphology and improved the flame resistance of RPUF nanocomposites. Therefore, we identify robust possibility that the RPUF nanocomposite produced can be useful as an insulation material.
Epoxy-coated Kenaf fibre-ABS (EKF-ABS) and uncoated kenaf fibre-ABS (KF-ABS) composites have been developed with the main objective to appraise the effect of varying processing temperatures on the mechanical and microstructural properties of the composites. FTIR spectroscopy was used to analyse the physico-chemical composition of the fibres, while SEM was used to examine the surface performance of the fibre before and after epoxy-coating. Thermal, mechanical and microstructural properties of the composites were characterized. The obtained results showed that the EKF-ABS composite exhibited better tensile, flexural and fatigue strengths and interfacial bonding than the KF-ABS composite. It was also observed that the processing temperatures (200, 220 and 240 ° C) did not cause significant change in the tensile and flexural strengths of EKF-ABS composite, but influenced markedly the fatigue behaviours of the composites. The impact strength, absorbed energy and fatigue strength of EKF-ABS composite were observed to be better than those of the KF-ABS composite, and are maximum at 200 ° C.
This study focused on the perception of private university students of SIWES programme. The authors administered questionnaires to 105 students and a response rate of 74% was achieved. Data was analysed using mean and Relative Importance Index (RII) and presented in TABLEs. The analysis showed amongst others that the SIWES programme is generally beneficial to students as it help them to acquire professional skills (RII = 0.846). They however stressed that getting a placement was their major challenge (RII = 0.700). Appropriate recommendations were made and a conclusion drawn from the study.
The current research has produced engineering plastics composite for automotive applications using waste recycled plastic recycled polyethylene terephthalate (RPET) bottles as the matrix and compounded with chemically modified natural kenaf fibers in comparison with virgin polyethylene terephthalate (PET) composites under the same processing conditions. Kenaf fibers were surface modified by alkali and epoxy coating treatment methods. The waste RPET bottles which were mechanically recycled were pulverized using a 5 mm mesh size aperture into flakes and melt‐mixed with 10 wt% of short kenaf fibers in a twin‐screw extruder and compression‐molded at 240°С optimized temperature. Mechanical and thermal analyses were performed on both RPET, virgin PET (VPET), and their constituent kenaf composites. Scanning electron microscopy (SEM) was carried out to assess the composite's morphological characteristics. The results show that both treated (TKF/RPET and TKF/VPET) composites gave higher mechanical properties compared to untreated (KF/RPET and KF/VPET) composites. RPET and its constituent composites show higher impact properties than VPET composites. However, the tensile and flexural strength of VPET composites was higher than that of recycled RPET composites. RPET and VPET showed melting peak temperatures of 252.9°C and 245.8°C respectively. Both treated TKF/RPET and TKF/VPET composites were more thermally stable and decomposed at higher temperatures compared to the untreated composites. The SEM results for both treated composites showed a strong fiber/matrix adhesion with no clear evidence of fiber degradation as compared to untreated composites. It can be concluded that RPET possessed similar thermal properties compared to its virgin counterpart and can serve as a substitute for virgin PET in the composite formulation. The development and production process of recycled polyethylene terephthalate (RPET) and virgin polyethylene terephthalate (VPET) composites reinforced with chemically modified kenaf fibers.
Introduction The willingness of Africa’s population to patronise the COVID-19 vaccines is critical to the efficiency of national immunisation programmes. This study surveys the views of adult African inhabitants toward vaccination and the possibility of participating or not participating in governments’ efforts to get citizens vaccinated. Method A cross-sectional online survey of adult Africans was undertaken from December 2020 to March 2021. Responses were anonymised. The Pearson Chi-square test was performed to determine whether or not there were any variations in knowledge, awareness, perception and acceptance of the COVID-19 vaccines among the participants. Binomial logistic regression was used to evaluate the factors associated with willingness to accept the COVID-19 vaccines and participate in immunisation programmes. Results The results indicate that COVID-19 vaccines are more likely to be used by adult Africans over the age of 18 who are largely technologically savvy (55 percent) if the vaccine is made broadly available. A total of 33 percent of those who responded said they were unlikely to receive the vaccine, with another 15 percent stating they were undecided. Aside from that, we found that vaccine hesitancy was closely associated with socio-demographic characteristics such as age, gender, education and source of information. We also found that there were widespread conspiracies and myths about the COVID-19 vaccines. Conclusion More than one-third of African adults who participated in the survey indicated they would not receive the COVID-19 vaccine, with majority of them expressing skepticisms about the vaccine’s efficacy. It is possible that many of the people who would not be vaccinated would have an impact on the implementation of a COVID-19 immunisation programme that is meant for all of society. Majority of the respondents were unwilling to pay for the COVID-19 vaccines when made available. An awareness campaign should be focused on promoting the benefits of vaccination at the individual and population levels, as well as on taking preemptive actions to debunk misconceptions about the vaccines before they become further widespread.
Commercial cultivation of Ganoderma species found in Nigeria does not exist. Four Ganoderma isolates (YCT-BKS, YCT-Q2, YCT-Q14, and YCT-Q18) collected in Lagos were tested for mycelia growth and cultivation in sawdust-based substrates. Internal transcribed spacer sequences (ITS1 and ITS4) from three isolates upon a GenBank BLAST search gave DNA sequence closest identities as YCT-BKS and YCT-Q14 = G. mbrekobenum and YCT-Q2 = G. enigmaticum. The mycelia growth rate was highest in YCT-BKS (1.2 cm/day), whereas the other three isolates averaged 0.7 cm/day. On substrate A (sawdust/water hyacinth, 7:3), the time to form primordia was 30 days for YCT-BKS, YCT-Q18, and YCT-Q14. YCT-Q2 and YCT-Q18 formed primordia (27 days) on substrate B (sawdust/sorghum, 3:2). YCT-BKS was the first to produce basidiocarp on substrate A (75 days after inoculation) and had the highest biological efficiency (BE) of 13.4%, followed by YCT-Q18 with BE of 12.1% on substrate B after 99 days. YCT-Q14 produced fruiting bodies after 92 days on substrate A, with a low BE of 7.0%. Results indicate the need to supplement sawdust (substrate C = 100% sawdust) to cultivate the Ganoderma spp. A mixture of sawdust and water hyacinth appears to be the best substrate among those tested. This is the first report on the domestication and cultivation of indigenous isolates of Ganoderma spp. from Nigeria on sawdust and water hyacinth. Water hyacinth is a noxious weed causing major problems in fresh waterways in Nigeria.
Titanium alloys have two primary phases (α + β) that are attributed to the α-stabiliser (aluminium) and β-stabiliser (niobium). The latter stabilisers shift α-phase to higher temperature while the former stabilisers shift the β-phase to lower temperatures. To extend their scope of application, (α + β)-phase titanium alloys can be micro-alloyed with β-eutetic elements (Mn, Cr, Si, Co etc) to form intermetallic compounds which are typically referred to as titanium aluminides (Ti-Al). Several intermetallic alloys can be formed in the Ti-Al phase diagram but only (α2)-Ti3Al and (γ)-TiAl are stable and of relevance to structural engineering since they can be used in industries spanning across energy, aerospace and tissue-engineering. In this study, a castable γ-Ti46.8Al1Cr0.2Si pre-alloyed powder, was micro-alloyed with Mn in order to examine if it can improve its tensile properties. When 1–2 at. % Mn is added to Ti-Al alloys, it is able to increase ductility, reduce oxidation resistance and shift the (α2 + γ)/ γ to the titanium side and decrease the Al content in the γ-phase. To effectively ascertain these effects Mn feed rates were varied from 0.2 to 1.0 rpm during the micro-alloying of γ-Ti46.8Al1Cr0.2Si through in-situ laser deposition to form γ-Ti46.8Al1Cr0.2Si-(xMn). The produced clads were characterised for chemistry and microstructure using scanning electron microscope. Results concluded that Al content decrease with an increase in Mn from 56 at. % to 49 at. %. Mn of 10.16 g/min had similar properties to the non-Mn alloyed sample. Moreover, it was shown in this work that laser processing decreased the tensile and yield strength of the alloy when compared to the as-cast in previous studies, and that 2.69 g/min and 10.16 g/min are lower and upper Mn values when ductility of the master alloy is to be improved.
Supercapacitors are used to store and release electrical charges like batteries and conventional capacitors. Unlike conventional capacitors, they have higher capacitance and power density, and they charge faster than batteries can. Supercapacitors are mainly classified as hybrid supercapacitors, pseudocapacitors, and electrochemical double-layer capacitors. To predict the application behaviour and optimization of supercapacitors, artificial intelligence, specifically machine language is utilized more recently. Models based on artificial intelligence are less complicated and maybe accurate enough. This paper identifies machine language models that have been employed to predict the supercapacitors’ performance.
Gamma titanium aluminideGamma-Titanium Aluminides (γ-TiAl)(γ-TiAl) alloys are lightweight materialsMaterials Science and Engineering with potential application for high-temperature components. But their ductility at room temperature impedes widespread production of parts via traditional processing routes. In this work, intermetallic Ti–Al–Si alloy was produced via laser in situ alloying from elemental powders by applying the laser engineered net shapingLaser Engineered Net Shaping (LENS) (LENS) technique. Isothermal annealing heat treatment was carried out at 1200, 1300, and 1400 °C for 1 h, followed by furnace cooling (FC). A second homogenization heat treatment was done at 850 °C for 6 h followed by FC. The microstructure was characterized by optical microscopy, (OM), scanning electron microscopy (SEM) equipped with an electron dispersion spectroscopy (EDS), and electron backscattered diffraction (EBSD) technique. The result shows precipitates of silicideSilicides (ζ-Ti5Si3) (ζ-Ti5Si3) grains with lamellae microstructure in the as-built Ti–Al–Si samples, while dense columnar grains of fully lamellar (FL) microstructure comprising of α2-Ti3Al and γ-TiAlGamma-Titanium Aluminides (γ-TiAl) were observed for the 1300 °C/1 h/FC/850 °C/6 h/FC heat-treated sample with ζ-Ti5Si3Silicides (ζ-Ti5Si3)-phasePhase Transformation at the grain boundaries. The high microhardness values of the samples were ascribed to the presence of ζ-Ti5Si3Silicides (ζ-Ti5Si3)-phasePhase Transformation being formed. This study established that laser in-situ alloying with standard heat treatment is feasible for the development of TiAl-based alloys.
This study assessed the seasonal distribution of trace metals in soft tissues of Tympanotonos fuscatus var radula, surrounding water, and sediment of Abule-Agege Creek in Southwest Nigeria. A non-significant variation (p > 0.05) in water physicochemical parameters occurred across wet and dry seasons. Metallic contamination (Copper, zinc, mercury, chromium, lead and cadmium) was found to be higher in T. fuscatus var radula than in water, and the sediment serves as a large depository of these trace metals. In this gastropod, the ability of metal accumulation from water (Bio-water accumulation) was higher than that from sediment (Bio-sediment accumulation). In addition, the linear regression models revealed positive relationship between tissue and sediment concentrations of lead and cadmium for both seasons. The estimated daily intake of investigated metals for both seasons was lower than the oral reference dose, while the target hazard quotient and total hazard index of individual metals were both less than 1, meaning that T. fuscatus var radula from the study region posed no health risk.
The advent of nanotechnology has resulted in an exponential improvement in drug delivery systems. Special attention is drawn to the use of nanogels which are nanosized hydrogels as effective drug delivery polymeric materials. Nanogels are 3-dimensional polymeric chains with sizes ranging from 100 to 200 nm. Their non-toxicity, biocompatibility, and biodegradability make them well suited for this purpose. Emerging studies have shown that the use of machine learning (ML) can optimize the drug-carrying and delivery of nanogels. This review would identify the mechanisms of nanogel drug delivery, commonly used machine learning models, areas of possible application of machine learning as it concerns nanogel drug delivery, and limitations in the application of machine learning.
The paper aims to study the thermo-mechanical analysis of a two-dimensional (2D) convex structural design sensitivity for typical engineering component application. COMSOL Multiphysics 5.3a was used to analyze the stress distribution, displacement along with thermal distribution of the component during high temperature application. The computational model incorporate two physics of solid mechanics and heat transfer in solids. A fine mesh size was applied on the component geometry which gives a high accuracy of the simulation results. The computational model results showed minimal displacement (12.14 × 10⁻⁴ m) of the Ti4822 alloy modelled under high temperature application. The model results also presented maximum stress concentration of 1.83 × 10⁸ N/m². A future paper will address 3D design sensitivity analysis in linear structural problems of titanium aluminide alloys during application.
Vehicle theft is continuously being reported as a global prevalent crime and the traditional mode of combating vehicle theft is faced with abnormalities hindering accurate, timely prediction and recovery of stolen vehicles from criminals. In this paper, we use Adaptive Neuro-Fuzzy Inference System (ANFIS) - a computational Artificial Intelligence (AI) technique to develop a model for minimizing investigation time and the number of deployed security operatives towards achieving a high success rate in the prediction, detection and recovery of stolen vehicles. A collection of vehicle theft and recovery data for (6) six consecutive years with fourteen (14) attributes collated by the Criminal Investigation Department of the Nigeria Police Force, Abeokuta, Ogun state were further analyzed through Dimensionality Reduction technique and Routine Activity Theory (RAT) approach to extract the most significant features. Datasets were sub-divided into 60%, 20% and 20% for training, testing and validating the model respectively. A significant result of 92.91% obtained with the Adaptive Neuro-Fuzzy Inference System (ANFIS) model showed that it is most efficient in predicting, detecting and recovering stolen vehicles as compared with other machine learning algorithms such as Random Tree, Naïve Bayes, J48 and Decision Rule of prediction accuracies of 86.51%, 71.24%, 67.68% and 55.73% respectively.
The purpose of this research is to develop new polymeric composite materials from the flamboyant pod (Delonix Regia), an agricultural waste, with polyester as a matrix and to investigate their properties and application areas. The flamboyant pod particles of 75 μm were incorporated into the polyester resin with different loadings of 10, 20, 30, 40, and 50 wt%. The influence of the pod particles on mechanical and morphological properties was determined and investigated. The results showed that 10 wt.% gave the best results for tensile, impact, and flexural properties with values of 40.6 MPa, 4.6 kJ/mm², and 86.82 MPa respectively, the values are however lower than the unfilled. The hardness properties increased with increasing filler loadings with values from 23.8 HV – 32.7 HV for 10 wt% - 50 wt% respectively. The micrographs of the fractured impact samples confirmed the 10 wt% filler loading having the best properties with homogenous dispersion of the flamboyant pod particles (FPP) within the polyester resin. It can be concluded that lightweight composites with reasonable properties have been developed at 10 wt % loading which is suitable for non-load bearing and indoor applications in the automotive and building industries as partition tops, walls, and boards owing to their saturation in water after 30 days of immersion. The flamboyant pod material can be further explored for added values with tougher polymer matrices.
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385 members
Oyeranmi Adigun
  • Department of Computer Technology
Olawale Paul Olatidoye
  • Department of Food Technology
Funmilayo Victoria Doherty
  • Environmental Biology Unit, Department of Biological science/ UNEVOC centre
Nwanneka Ofodile
  • DEPARTMENT OF BIOLOGICAL SCIENCES
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Address
Yaba College of Technology, , 101212, Lagos, Lagos, Nigeria
Head of institution
Engr Femi Omokungbe
Website
www.yabatech.edu.ng