Department of Metallurgical and Materials Engineering

Permanent URI for this community

https://ir.unilag.edu.ng/handle/123456789/3477

Browse

Browsing Department of Metallurgical and Materials Engineering by Author "Adebisi, J.A."

Now showing 1 - 12 of 12
  • Item
    Open Access
    Cassava Leaf Nanoparticles (CLNPs) as a Potential Additive to Anti-Corrosion Coatings for Oil and Gas Pipeline
    (Tribology in Industry, 2017) Kolawolec; Kolawole, F.O.; Kolawole, S.K.; Agunsoye, J.O.; Bello, S.A.; Adebisi, J.A.; Okoye, O.C.; Hassan, S.B.
    Characterization of synthesized cassava leaf nanoparticles (CLNPs) was carried out using SEM/EDX and Gwyddion software, XRD and TEM for cassava leaves (CL) ball milled at 36, 48, 60 and 72 hours. The morphological study was done using SEM and the Gwyddion software was used to determine the particle sizes from the SEM images. The particle size range for the un-milled cassava leaves (CL) was between 1.88 + 0.09 to 19.53 + 0.98 µm. After milling for 36, 48, 60 and 72 hours the average particle sizes were 4.96 + 0.25, 3.51 + 0.18 µm, 86.90 + 4.35, 74.50 + 3.73 nm respectively. Crystallite size of 23.94 + 1.20 nm was obtained by XRD using Scherrer equation after milling for 72 hours and the XRD results revealed the presence of compounds such as SiO2, CaCO3, Ca2(SO4)2H2O and CaC2O4(H2O). Furthermore, TEM was used to determine nanoparticles after milling for 72 hours and the particle size ranged from 9.16 + 0.46 to 58.20 + 2.91 nm for cassava leaf nanoparticles (CLNPs) and EDX results showed trace element of O, Si, Ca, K, Fe and S in the CL milled for 72 hours . FTIR was also carried out to determine the nature of bond that exist in the organic compounds in CLNPs and GCMS analysis was used to reveal the organic compounds that were present in CLNPs. Anti-Corrosion coatings reduces corrosion activities to the bearest minimum.
  • Item
    Open Access
    Effect Of Aluminium Particles On Mechanical And Morphological Properties Of Epoxy Nanocomposites
    (APTEFF, 2017) Bello, S.A.; Agunsoye, J.O.; Adebisi, J.A.; Hassan, S.B.
    Bumper is a front or rear part of automobiles. It is designed and shaped to be impact absorbing and protecting automobiles from damage in low impact collisions. Initially, they were made from heavy steels, increasing the weight of automobiles and fuel consumption. Also, high impacts of steel bumpers on pedestrians during accidental collision cause fatalities and or disabilities. An effort to enhance fuel efficiency, safety, freedom of design and shape detailing, heavy alloys for automobile applications are now being replaced with polymeric composites. Aluminium micro particles and nanoparticles were prepared from aluminium cans through sand casting, lathe machine spinning, and ball milling techniques. Both types of aluminium particles were incorporated into a mixture of diglycidyl ether of bisphenol A (DGEBA, epoxy resin) cured with amine base hardener (ABH). Phases of the epoxy polymer and composites were identified using Xray Diffraction (XRD). Spatial arrangement of the phases within the matrix and their elemental composition were examined using Scanning Electron Microscope with attached energy dispersive X-ray spectroscopy (SEM/EDX). Tensile, impact and micro hardness tests were conducted on the prepared epoxy/aluminium composites. Results of the XRD showed the presence of aluminium compounds/phases due to chemical reactions between aluminium particles and DGEBA/ABH system. SEM confirmed a homogeneous distribution of the phases within the epoxy matrix, and that there is a strong adhesion between the epoxy matrix and aluminium particles. Correlation between the mechanical properties of the prepared nanocomposite and the procured bumper materials exhibited a fair suitability of the prepared nanocomposites for automobile applications.
  • Item
    Open Access
    Extraction of Silica from Cassava Periderm using Modified Sol-Gel Method
    (Nigerian Journal of Technological Development, 2018) Adebisi, J.A.; Agunsoye, J.O.; Bello, S.A.; Haris, M.; Ramakokovhu, M.M.; Daramola, M.O.; Hassan, S.B.
    Cassava peridem wastes are generated and disposed indiscriminately or burnt due to zero economic value. In this study, modified sol-gel synthesis of amorphous silica nanoparticles from cassava periderm (CP) was investigated. The wastes were pretreated with HCl to remove soluble metallic impurities. Both treated and untreated CP flakes were calcined at 700 oC to obtain their respective ashes. The ashes were leached with HCl to remove soluble metallic oxides and thereafter sol-gelled to obtain silica gel modified with ethylene glycol. The gel was dried at 80 oC for 18 hours and then characterized using SEM, EDX, XRD, FT-IR, Raman, TEM and PSA. The SEM micrographs showed that silica modified with ethylene glycol is less agglomerated with higher silica yield and lower particle sizes. All the silica produced showed similar functional groups and non-crystallinity. The silica nanoparticles could be used as starting materials for synthesis of silicon nanoparticles
  • Item
    Open Access
    Extraction of Silica from Sugarcane Bagasse, Cassava Periderm and Maize Stalk: Proximate Analysis and Physico-Chemical Properties of Wastes
    (Waste Biomass Valor, 2017) Adebisi, J.A.; Agunsoye, J.O.; Bello, S.A.; Kolawole, F.O.; Ramakokovhu, M.M.; Daramola, M.O.; Hassan, S.B.
    Indiscriminate disposal and burning of agricultural wastes constitute environmental pollution and increase in greenhouse gases emission. Renewable nature and availability of agricultural wastes has stimulated researchers to explore “wastes to wealth creation” policy. Three agricultural wastes were investigated for potential use for silica production. Proximate analysis, thermogravimetric analysis (TGA), compositional analysis, calcination and statistical analysis were carried out to quantify the ash and establish presence of silica. Response surface methodology was used for statistical analysis of CP calcination. The proximate analysis showed that sugarcane bagasse, cassava periderm and maize stalk ash contents are 1.73, 4.93 and 4.80%, respectively. The EDS results showed that their ashes contain 5.22, 6.10 and 7.01% silicon, respectively. XRF results revealed presence of 38% SiO2 in CP ash. XRD revealed presence of silica and silicates phases. TGA shows that their calcination temperature must be above 500 °C. Numerical optimization of CP calcination gave optimum condition of 700 °C for 270 min to attain 82% weight loss. Calcination regression equation exhibited high coefficient of determination (R2) of 0.8225. The three wastes contain silica and silicates from which silica could be extracted. Calcination temperature and time have been established to be significant in ash content enhancement.
  • Item
    Open Access
    Flexural Performances of Epoxy Aluminium Particulate Composites
    (ENGINEERING JOURNAL, 2018) Bello, S.A.; Agunsoye, J.O.; Adebisi, J.A.; Raji, N.K.; Adeyemo, R.G.; Alabi, A.G.F.; Hassan, S.B.
    Polymers are characterised with lightness, ease of formability and resistance to chemical attack but their modulus and strength are low. Epoxy was reinforced with aluminium particles of different sizes. Bond, functional group and chemical formulae of the composite phases were examined using Fourier Transform Infrared Spectroscopy (FTIR) and X-ray diffractometer. The flexural test was also conducted on the developed composites via three-point method. Analysis of variance (ANOVA) was performed using aluminium percentage by weight (wt%) and sizes (Ps) as the predictor variables. Results indicated different chemical formulae of the composite phases. A maximum of 124.44 % increase in flexural modulus was found at 12 wt% reinforcement addition. Probability value, 0.000 for each of wt% and Ps affirm evenly significant influence of both variables on flexural modulus of the composites. Hence, the developed multiple regression model can be used for predicting the flexural modulus of epoxy particulate composites within and outside the scope of experiment
  • Item
    Open Access
    Optimisation of charge ratios for ball milling synthesis: agglomeration and refinement of coconut shells
    (Engineering and Applied Science Research, 2018) Bello, S.A.; Agunsoye, J.O.; Adebisi, J.A.; Hassan, S.B.
    Agglomeration is an attraction of fine particles for one another due to their high surface energy, leading to formation of particle colonies known as agglomerates. When a polymeric or metallic matrix is reinforced with particles, agglomerates usually create regions of discontinuity or weak particle adhesion within the matrix and degrade mechanical properties of the resulting composites. In ball-milling synthesis of nanoparticles, formation of agglomerates can be controlled through optimisation of milling parameters. In this study, coconut shell (lignocellulosic) nanoparticles were synthesised by varying the charge ratios from 2.5 to 40 at constant milling duration (70 hours), speed in terms of drum/vial rotation (194 revolution per minute) and ball sizes (5- 60 mm). Assessment of the effects of charge ratios (CRs) on the morphologies and particles sizes of uncarbonised coconut shell nanoparticles (UCSnp) was studied. The synthesised UCSnp were characterised using electron microscopy and X-ray diffractometry (XRD). The results showed various morphologies and orientations of UCSnp with changes in the CRs. Size determination using XRD and SEM revealed a reduction in particle size as the CR increased up to a value of 10. At higher CRs, further reduction in the average particle size was not observable. This could be linked to a balance between particle refinement and agglomeration at these higher CRs. Although particle agglomeration was apparent above CR values of 10, sizes of the UCSnp obtained above this CRs were much smaller than the initial size (37 μm) of the coconut shell precursor particles. This affirmed the ball milling synthesis as a particle refinement process, but not a coarsening/agglomeration process. The results obtained from statistical analyses show agreement with experimental results.
  • Item
    Open Access
    Optimisation of charge ratios for ball milling synthesis: agglomeration and refinement of coconut shells
    (Engineering and Applied Science Research, 2018) Bello, S.A.; Agunsoye, J.O.; Adebisi, J.A.; Hassan, S.B.
    Agglomeration is an attraction of fine particles for one another due to their high surface energy, leading to formation of particle colonies known as agglomerates. When a polymeric or metallic matrix is reinforced with particles, agglomerates usually create regions of discontinuity or weak particle adhesion within the matrix and degrade mechanical properties of the resulting composites. In ball-milling synthesis of nanoparticles, formation of agglomerates can be controlled through optimisation of milling parameters. In this study, coconut shell (lignocellulosic) nanoparticles were synthesised by varying the charge ratios from 2.5 to 40 at constant milling duration (70 hours), speed in terms of drum/vial rotation (194 revolution per minute) and ball sizes (5- 60 mm). Assessment of the effects of charge ratios (CRs) on the morphologies and particles sizes of uncarbonised coconut shell nanoparticles (UCSnp) was studied. The synthesised UCSnp were characterised using electron microscopy and X-ray diffractometry (XRD). The results showed various morphologies and orientations of UCSnp with changes in the CRs. Size determination using XRD and SEM revealed a reduction in particle size as the CR increased up to a value of 10. At higher CRs, further reduction in the average particle size was not observable. This could be linked to a balance between particle refinement and agglomeration at these higher CRs. Although particle agglomeration was apparent above CR values of 10, sizes of the UCSnp obtained above this CRs were much smaller than the initial size (37 μm) of the coconut shell precursor particles. This affirmed the ball milling synthesis as a particle refinement process, but not a coarsening/agglomeration process. The results obtained from statistical analyses show agreement with experimental results.
  • Item
    Open Access
    Optimization of tensile properties of epoxy aluminum particulate composites using regression models
    (Journal of King Saud University – Science, 2018) Bello, S.A.; Agunsoye, J.O.; Adebisi, J.A.; Adeyemo, R.G.; Hassan, S.B.
    Aluminum particles (sourced from aluminum can wastes) were incorporated into diglycidyl ether of bisphenol A (DGEBA) cured with 1,3-diethanamine benzene hardener. Phases occupying the infusible cross linked-developed epoxy composite structures were identified and their spatial arrangements were also examined. The mechanical property tests conducted on the developed epoxy composites include tensile, flexural, impact toughness and micro hardness tests. The density of the epoxy composite sample was determined using Archimedes’ principle. Regression models were developed, confirmed and validated to appraise effects of aluminum particle sizes and percentage weight on the tensile strength. XRD results indicated a chemical reaction between epoxy system and aluminum particles. There is a fair homogenous distribution of the second phase particles within the developed epoxy structure. Deductions from mechanical property tests revealed epoxy/10% aluminum nanoparticle composite (E/10%Alnp) having optimal tensile strength of 18.58 Nmm 2 with flexural strength of 130.87 Nmm 2, impact energy of 16.30 J and micro hardness value of 12.03 HV. The mechanical property values of E/10% Alnp Nanocomposite are comparable with those of existing bumper materials. Moreover, the regression models agree with experiments.
  • Item
    Open Access
    Particle Size Analysis and Characterization of Cassava (Manihot esculenta crantz) Stem Nanoparticles (CSNPs) via a Top-down Approach
    (Annals of Science and Technology - B, 2016) Kolawole, F.O.; Agunsoye, J.O.; Bello, S.A.; Adebisi, J.A.; Hassan, S.B.
    Characterization of synthesized cassava stem nanoparticles (CSNPs) was carried out using SEM/EDX and Gwyddion software, XRD and TEM for cassava stem (CS) ball milled at 36, 48, 60 and 72 h. The morphology study was done using SEM and the Gwyddion software was used to determine the particle size from the SEM images. The particle size range for the un-milled cassava stem (CS) was between 1.02+ 0.05 to 19.99+ 1.00 µm. After milling for 36, 48, 60 and 72 h the average particle size were 0.93+0.05 µm, 128.20+ 6.41, 111.20+ 5.56, 101.20 + 5.06 nm respectively. The particle size of 11.83+0.59 nm was obtained by XRD using Scherrer equation after milling for 72 h and the XRD results revealed the presence of compounds such as SiO2, CaCO3, Ca3SiO5 and Al2O3. Furthermore, TEM was used to determine nanoparticles after milling for 72 h and the particle size ranged from 8.35 + 0.42 to 51.74 + 2.59 nm for cassava stem nanoparticles (CSNPs) and EDX result showed trace element of O,Si, Ca, Al, K, Ti, Fe andP in the CS milled for 72 h.
  • Item
    Open Access
    Physical Properties Of Coconut Shell Nanoparticles
    (Kathmandu University Journal of Science, Engineering and Technolog, 2016) Bello, S.A.; Agunsoye, J.O.; Adebisi, J.A.; Kolawole, F.O.; Hassan, S.B.
    Physical properties such as apparent density, bulk density, compressibility index and particle sizes of carbonized and uncarbonized coconut shell nanoparticles produced through top down approach have been studied. Percentage composition of the coconut fruit was determined using five different coconut fruit samples. Results revealed that coir occupies the highest percentage; coconut shells account for 15 % while the flesh and liquid occupy 30 % of the whole coconut fruit. The apparent densities of the uncarbonized and carbonized coconut shell nanoparticles obtained at 70 hours of milling are 0.65 g/cm3 and 0.61 g/cm3 respectively. Their respective compressibility indices and average particle sizes are 46.4 % and 69.7 %; 50.01 nm and 14.29 nm. The difference in the particle sizes of the carbonized and uncarbonized coconut shell nanoparticles can be linked with reduction in the moisture content and volatiles of the carbonized coconut shell nanoparticles due to carbonization process. The reduction in the moisture and volatiles results in the enhanced hardness and brittleness of the carbonized coconut shells which facilitate their breakage during the course of milling than that of the uncarbonized coconut shells.
  • Item
    Open Access
    Potential of producing solar grade silicon nanoparticles from selected agro-wastes: A review
    (Solar Energy, 2017) Adebisi, J.A.; Agunsoye, J.O.; Bello, S.A.; Ahmed, I.I.; Ojo, O.A.; Hassan, S.B.
    The U.S. Energy Information Administration (EIA) stated that Nigeria generates around 3080 MW of electricity but with actual estimated demand of 10,000 MW. Due to the low electricity generation, total energy consumption profile of Nigeria showed that about 99% of the energy consumed is derived from fossil fuels which invariably contribute to greenhouse gases emission. Electricity, if readily available at low cost, can easily replace the fossil fuels which pose adverse effect on the citizen and climate. Solar photovoltaic is identified as an effective renewable energy source that has proven to be a promising candidate for provision of clean and sustainable electricity. Silicon is the leading commercialized terrestrial PV material for making solar cell due to its relative efficiency. This review work highlights the viability of using abundant agricultural wastes in Nigeria to produce nano-sized solar grade silicon employing methods that will require less energy. Details of previous silicon (nanoparticles) synthesized from agricultural wastes are dissected. Production of silicon nanoparticles from this origin could provide low cost solar grade silicon compared with high temperature robust methods currently been used to obtain them. Hence various methods of producing nanoparticles are highlighted.
  • Item
    Open Access
    Synthesis and Characterization of Cassava Bark Nanoparticles
    (Materials Research Society, 2018) Kolawolea, F.O.; Kolawole, S.K.; Agunsoye, J.O.; Bello, S.A.; Adebisi, J.A.; Soboyejo, W.O.; Hassan, S.B.
    Synthesis and characterization of cassava bark nanoparticles (CBNPs) was carried out using ball milling at 36, 48, 60 and 72 hours. The morphology study was done using SEM and the Gwyddion software was used to determine the particle sizes from the SEM images. The particle distribution for the un-milled cassava bark (CB) was between 1.25 + 0.06 to 19.92 + 1.00 µm, while after milling for 36, 48, 60 and 72 hours the average particle size were 4.07 + 0.20, 4.00 + 0.20 µm, 80.90 + 4.05, 74.50 + 3.73 nm respectively. 13.68 + 0.68 nm was obtained by XRD using Scherrer equation after milling for 72 hours and the XRD results revealed the presence of compounds such as SiO2, CaCO3 and KAlSi3O8. TEM was used to determine nanoparticle size distribution after milling for 72 hours and the particle size ranged from 9.73 + 0.49 to 114.60 + 5.73 nm for cassava bark nanoparticles (CBNPs), EDX results showed trace element of Si, Ca, K, Fe, Al, O in the CB milled for 72hours.