Talabi Segun Isaac | University of Ilorin, Ilorin Kwara State Nigeria (original) (raw)

Papers by Talabi Segun Isaac

Composites Science and Technology, 2000

Thermal aging treatments under both atmosphere and vacuum environments at temperatures of 100°C t... more Thermal aging treatments under both atmosphere and vacuum environments at temperatures of 100°C to 300°C for durations from 2 to 8 h have been made on Kevlar-29 yarns. The effects of thermal aging on tensile strength, tensile strain and the Young's modulus of the single fibre have been evaluated. It was established that both the tensile strength and the tensile

This study investigated the combined effect of cold rolling and heat treatment on the mechanical ... more This study investigated the combined effect of cold rolling and heat treatment on the mechanical properties of Al-Ti alloy. Samples of the alloy are cast in metal mould to obtain 0.94-2.19wt% mixes of titanium. These samples are grouped into untreated (as-cast) and those that are cold rolled to fifty percent reduction, homogenized at 500⁰C and soaked for one hour. The cold rolled and heat treated samples are normalized (<em>RT_n</em>) and quench-tempered (<em>RT_q-t</em>) at 100⁰C. All these samples are subjected to tensile, micro-hardness and microstructural evaluation. Results show remarkable improvement in the mechanical properties of the cold rolled and heat treated samples compared to the as-cast. In particular, the <em>RT_q-t</em> samples containing titanium in the range of 1.7-2.2% demonstrates improve tensile strength by 24.7%, y...

Journal of Electrochemical Science and Engineering, 2017

This study investigates the inhibition potential of Vernonia amygdalina stem extract (VAE) on the... more This study investigates the inhibition potential of Vernonia amygdalina stem extract (VAE) on the corrosion of mild carbon steel immersed in 1 M HCl solution containing various concentrations of the inhibitor. The corrosion rate and inhibition efficiency were evaluated using mass loss and adsorption techniques. The results revealed that VAE efficiently inhibits the corrosion rate of mild carbon steel immersed in the acidic medium. The concentration of 0.6 g/L provides the highest inhibition efficiency of 78.1 %. The adsorption process was consistent with the physisorption mechanism and obeyed the Langmuir isotherm. The functional groups responsible for inhibition were identified using Fourier-transformed infrared (FTIR) spectra. The surface morphology of the corroded samples examined with scanning electron microscopy (SEM) revealed the presence of protective oxide layer. Inhibition efficiency was found dependet on the presence of oxalate, phytate, tannins, saponins and flavonoids in the VAE. It has been concluded that VAE is safe, cheap and efficient corrosion inhibitor for mild carbon steel.

Journal of Minerals and Materials Characterization and Engineering, 2012

The effect of palm kernel shell on the microstructure and mechanical properties of recycled polye... more The effect of palm kernel shell on the microstructure and mechanical properties of recycled polyethylene (RLDPE) reinforced with palm kernel shell particulate composite was evaluated to assess the possibility of using it as a new material for engineering applications. The composites were produced by compounding and compressive moulding technique by varying the Palm kernel shell particle from 5-25 vol% with particles size of 150, 300 and 400 µm. The microstructure (SEM/EDS) and the mechanical properties of the composites were investigated. The hardness of the composite increases with increase in palm kernel shell content and the tensile strength of the composite increased to optimum of 5 vol%. Scanning electron Microscopy (SEM) of the composites surfaces indicates fairly interfacial interaction between the palm kernel shell particles and the RLDPE matrix. The composites produced with 150 µm particle size have the best properties of the entire grade. Hence this grade can be use for interior applications such as car seat, dash board, and car interior for decorative purposes or other interior parts of automobile where high strength is not considered a critical requirement.

Journal of Minerals and Materials Characterization and Engineering, 2013

This paper investigates the wear characteristic of grey cast iron composition under dry lubricati... more This paper investigates the wear characteristic of grey cast iron composition under dry lubrication conditions. The effects of sliding speed, applied load, time and percentage of ferrosilicon additions, on the wear rate of grey cast iron were studied. The set of experimental data were taken in a controlled and sequential manner. Scanning electron microscope was used to examine the morphology of the samples as well as the worn out surfaces. Linear regression equation and analysis of variances (ANOVA) showed that the main effect of silicon additions, load and speed variable are more pronounced on the wear behaviour of the grey cast iron. Also, the result showed that the additions of silicon improved the wear resistance of the grey cast iron as the wear parameters such as speed, load and time varied. The study showed that wear transition occurred at 3.2% silicon addition.

Journal of Minerals and Materials Characterization and Engineering, 2013

International Journal of Applied Ceramic Technology, 2020

The properties of carbon-containing refractories (CCRs) depend on the presence of carbon with fea... more The properties of carbon-containing refractories (CCRs) depend on the presence of carbon with features close to graphite. However, the thermosetting resins that are used to bind such refractories together during the initial preparation stage usually produce non-graphitic carbon when sintered, which can impair their overall performance. Based on this, ferrocene was used to induce graphitic carbon generation from a resole-type phenolic resin during a sequential carbonization operation. The resin formulation containing the graphitizing agent was then used to prepare resin-bonded Al2O3-MgO castables. The role of in situ graphitization of the modified binder on the properties such as cold crushing strength, apparent porosity, and oxidation resistance was examined. The results show that crystallization of the binder carbon can improve the castable oxidation resistance. At ambient temperature, no significant difference was observed in the samples&#39; physicomechanical properties. Nevertheless, holding time during the initial curing stage at 50°C played a significant role on those properties.

Int J Appl Ceram Technol., 2020

The properties of carbon-containing refractories (CCRs) depend on the presence of carbon with fea... more The properties of carbon-containing refractories (CCRs) depend on the presence of carbon with features close to graphite. However, the thermosetting resins that are used to bind such refractories together during the initial preparation stage usually produce non-graphitic carbon when sintered, which can impair their overall performance. Based on this, ferrocene was used to induce graphitic carbon generation from
a resole-type phenolic resin during a sequential carbonization operation. The resin formulation containing the graphitizing agent was then used to prepare resin-bonded Al2O3-MgO castables. The role of in situ graphitization of the modified binder on the properties such as cold crushing strength, apparent porosity, and oxidation resistance was examined. The results show that crystallization of the binder carbon can improve the castable oxidation resistance. At ambient temperature, no significant difference was observed in the samples' physicomechanical properties. Nevertheless, holding time during the initial curing stage at 50°C played a significant role on those properties.

Polypropylene (PP) composites with cellulose nanofibril (CNF), lignocellulose nanofibril (LCNF) o... more Polypropylene (PP) composites with cellulose nanofibril (CNF), lignocellulose nanofibril (LCNF) or bleached kraft wood pulp (BWKP) cellulose microfibril compatibilized by maleic anhydride grafted polypropylene were produced by different approaches. Samples containing 10-30 wt% filler were prepared by mixing cellulose aqueous suspensions and PP through solid-state shear pul-verization. The flakes obtained were compounded by twin-screw melt extru-sion (MSE) followed by injection molding (IM) into standard specimens. Reference samples with 30 wt% CNF or LCNF were prepared through a standard procedure, which involved freeze-drying of nanofibrils aqueous suspen-sions before MSE and IM, whereas a sample with 30 wt% BWKP was prepared directly by MSE and IM. Injection-molded specimens were characterized by scanning electron microscopy, differential scanning calorimetry, thermogravimetry, and tensile and notched impact tests. The thermal behavior of the PP matrix in the composites was not significantly affected by the filler type and content and processing route as well. CNF and LCNF reinforced PP composites showed inferior mechanical properties, due to the formation of nanofibrils agglomerates in the PP matrix, regardless of the processing route adopted. Highly filled (30 wt%) BWKP composites presented superior mechanical properties with significant increase in the modulus, tensile strength, and impact strength due to the formation of well-dispersed microfibrils bundles in the PP matrix. A comparative analysis showed that the composites developed in this study present similar or even superior mechanical performance for given filler content to other natural fiber reinforced PP composites reported in the literature. K E Y W O R D S bleached wood, cellulose nanofibrils, mechanical properties, polypropylene, solid-state shear pulverization

Environmental friendliness and cost demand the development of lignin-modified phenolic (LPF) resi... more Environmental friendliness and cost demand the development of lignin-modified phenolic (LPF) resins for application as a binder for carbon-containing refractories (CCRs) production. Moreover, the in-situ graphitization of such resins can produce crystalline carbon, which is an essential component of CCRs. Consequently, this study investigated LPF resins graphitization using ferrocene, boron oxide and boric acid. The modified resins were synthesized using thermally treated kraft lignin based on 1.5 formaldehyde to phenol molar ratio and with up to 30 wt.% lignin as phenol replacement. The resins chemical composition and the structural organization and oxidation resistance of carbons derived from the plain resins and those containing the graphitizing additives were determined. The results showed that ferrocene and the boron compounds could induce graphitic carbon generation when carbonizing LPF resins at 1500 °C for 5 hours. The best graphitization level (73%) was achieved when 10 wt.% boric acid was added to the resin produced with 20 wt.% lignin. Regarding the formulations containing ferrocene, the highest amount of graphitic carbon (48%) was generated when 5 wt.% of this additive was added to the resin synthesized with 10 wt.% lignin. The carbons derived from the formulations containing boron oxide presented the best oxidation resistance.

World Academy of Science, Engineering and Technology, 2014

This study investigated the combined effect of cold rolling and heat treatment on the mechanical ... more This study investigated the combined effect of cold rolling and heat treatment on the mechanical properties of Al-Ti alloy. Samples of the alloy are cast in metal mould to obtain 0.94-2.19wt% mixes of titanium. These samples are grouped into untreated (as-cast) and those that are cold rolled to fifty percent reduction, homogenized at 500 0 C and soaked for one hour. The cold rolled and heat treated samples are normalized (RT n) and quench-tempered (RT q-t) at 100 0 C. All these samples are subjected to tensile, micro-hardness and microstructural evaluation. Results show remarkable improvement in the mechanical properties of the cold rolled and heat treated samples compared to the as-cast. In particular, the RT q-t samples containing titanium in the range of 1.7-2.2% demonstrates improve tensile strength by 24.7%, yield strength, 28%, elastic modulus, 38.3% and micro-hardness, 20.5%. The Al 3 Ti phase being the most stable precipitate in the α-Al matrix appears to have been responsible for the significant improvement in the alloy's mechanical properties. It is concluded that quench and temper heat treatment is an effective method of improving the strength-strain ratio of cold rolled Al-.0.9-2.2%Ti alloy.

This study investigates the inhibition potential of Vernonia amygdalina stem extract (VAE) on the... more This study investigates the inhibition potential of Vernonia amygdalina stem extract (VAE) on the corrosion of mild carbon steel immersed in 1 M HCl solution containing various concentrations of the inhibitor. The corrosion rate and inhibition efficiency were evaluated using mass loss and adsorption techniques. The results revealed that VAE efficiently inhibits the corrosion rate of mild carbon steel immersed in the acidic medium. The concentration of 0.6 g/L provides the highest inhibition efficiency of 78.1 %. The adsorption process was consistent with the physisorption mechanism and obeyed the Langmuir isotherm. The functional groups responsible for inhibition were identified using Fourier-transformed infrared (FTIR) spectra. The surface morphology of the corroded samples examined with scanning electron microscopy (SEM) revealed the presence of protective oxide layer. Inhibition efficiency was found dependet on the presence of oxalate, phytate, tannins, saponins and flavonoids in the VAE. It has been concluded that VAE is safe, cheap and efficient corrosion inhibitor for mild carbon steel.

The effect of molybdenum on the morphological and wear behaviour of Nigeria Foundries grey cast i... more The effect of molybdenum on the morphological and wear behaviour of Nigeria Foundries grey cast iron (8) [NFgrey(8)] has been studied. The microstructural and mechanical properties of the cast samples for the control and the NFGrey(8)/Molybdenum alloy were characterised using SEM, XRD, Brinell Hardness and impact energy testing Machine respectively. MATLAB linear curve fitting technique was used to obtain the approximate linear equation via first differential approach. The results show that molybdenum addition improved significantly the wear resistance of the NFGrey(8) cast iron. However, the toughness of the alloy was sacrificed. The strong and hard intermetallic compounds within the matrix are attributable to wear resistance of the NFGrey(8)/Mo alloy.

International Journal of Metals, 2013

This paper examines the effects of heat treatment processes on the mechanical properties of as-ca... more This paper examines the effects of heat treatment processes on the mechanical properties of as-cast Al-4% Ti alloy for structural applications. Heat treatment processes, namely, annealing, normalizing, quenching, and tempering, are carried out on the alloy samples. The mechanical tests of the heat treated samples are carried out and the results obtained are related to their optical microscopy morphologies. The results show that the heat treatment processes have no significant effect on the tensile strength of the as-cast Al-4% Ti alloy but produce significant effect on the rigidity and strain characteristic of the alloy. With respect to the strain characteristics, significant improvement in the ductility of the samples is recorded in the tempered sample. Thus, for application requiring strength and ductility such as in aerospace industries, this tempered heat treated alloy could be used. In addition, the quenched sample shows significant improvement in hardness.

2014 International Conference on Interactive Collaborative Learning, Dec 1, 2014

The present state of engineering practices in our country has called for review of engineering cu... more The present state of engineering practices in our country has called for review of engineering curricula to make it more proactive and relevant to the industrial and societal needs. It is imperative that students be shown the difference between studying engineering and becoming an engineer. There is need for strong industrial interaction in our education for the students to know the types of problems engineers face, the concepts, processes, and tools they use to solve those problems, and the personal and professional attributes essential to be a team player in solving engineering problems. An attempt was made to evaluate all this variables in this paper.

2014 International Conference on Interactive Collaborative Learning (ICL), 2014

The present state of engineering practices in our country has called for review of engineering cu... more The present state of engineering practices in our country has called for review of engineering curricula to make it more proactive and relevant to the industrial and societal needs. It is imperative that students be shown the difference between studying engineering and becoming an engineer. There is need for strong industrial interaction in our education for the students to know the types of problems engineers face, the concepts, processes, and tools they use to solve those problems, and the personal and professional attributes essential to be a team player in solving engineering problems. An attempt was made to evaluate all this variables in this paper.

Journal of Minerals and Materials Characterization and Engineering, Aug 20, 2012

The morphology and mechanical properties of coconut shell reinforced polyethylene composite have ... more The morphology and mechanical properties of coconut shell reinforced polyethylene composite have been evaluated to establish the possibility of using it as a new material for engineering applications. Coconut shell reinforced composite was prepared by compacting low density polyethylene matrix with 5% -25% volume fraction coconut shell particles and the effect of the particles on the mechanical properties of the composite produced was investigated. The result shows that the hardness of the composite increases with increase in coconut shell content though the tensile strength, modulus of elasticity, impact energy and ductility of the composite decreases with increase in the particle content. Scanning Electron Microscopy (SEM) of the composites (with 0% -25% particles) surfaces indicates poor interfacial interaction between the coconut shell particle and the low density polyethylene matrix. This study therefore exploits the potential of agro-based waste fiber in Nigeria as an alternative particulate material for the development of a new composite.

This paper investigates the wear characteristic of grey cast iron composition under dry lubricati... more This paper investigates the wear characteristic of grey cast iron composition under dry lubrication conditions. The effects of sliding speed, applied load, time and percentage of ferrosilicon additions, on the wear rate of grey cast iron were studied. The set of experimental data were taken in a controlled and sequential manner. Scanning electron microscope was used to examine the morphology of the samples as well as the worn out surfaces. Linear regression equation and analysis of variances (ANOVA) showed that the main effect of silicon additions, load and speed variable are more pronounced on the wear behaviour of the grey cast iron. Also, the result showed that the additions of silicon improved the wear resistance of the grey cast iron as the wear parameters such as speed, load and time varied. The study showed that wear transition occurred at 3.2% silicon addition.

The effect of palm kernel shell on the microstructure and mechanical properties of recycled polye... more The effect of palm kernel shell on the microstructure and mechanical properties of recycled polyethylene (RLDPE) reinforced with palm kernel shell particulate composite was evaluated to assess the possibility of using it as a new material for engineering applications. The composites were produced by compounding and compressive moulding technique by varying the Palm kernel shell particle from 5 -25 vol% with particles size of 150, 300 and 400 µm. The microstructure (SEM/EDS) and the mechanical properties of the composites were investigated. The hardness of the composite increases with increase in palm kernel shell content and the tensile strength of the composite increased to optimum of 5 vol%. Scanning electron Microscopy (SEM) of the composites surfaces indicates fairly interfacial interaction between the palm kernel shell particles and the RLDPE matrix. The composites produced with 150 µm particle size have the best properties of the entire grade. Hence this grade can be use for interior applications such as car seat, dash board, and car interior for decorative purposes or other interior parts of automobile where high strength is not considered a critical requirement. A. J. OLUMUYIWA ET AL. 826 Plate 1. EDS/SEM morphology of the recycled polyethylene. A. J. OLUMUYIWA ET AL. 827 Plate 2. EDS/SEM morphology of the recycled polyethylene reinforced with 10 vol% at 150 µm size. Plate 3. EDS/SEM morphology of the recycled polyethylene reinforced with 25 vol%, 150 µm size. Plate 4. EDS/SEM morphology of the recycled polyethylene reinforced with 5 vol%, 300 µm size. A. J. OLUMUYIWA ET AL. 828 Plate 5. EDS/SEM morphology of the recycled polyethylene reinforced with 20%, 300 µm size. Plate 6. EDS/SEM morphology of the recycled polyethylene reinforced with 15 vol%, 400 µm size. Plate 7. EDS/SEM morphology of the recycled polyethylene reinforced with 25 vol%, 400 µm size.

Composites Science and Technology, 2000

Thermal aging treatments under both atmosphere and vacuum environments at temperatures of 100°C t... more Thermal aging treatments under both atmosphere and vacuum environments at temperatures of 100°C to 300°C for durations from 2 to 8 h have been made on Kevlar-29 yarns. The effects of thermal aging on tensile strength, tensile strain and the Young&amp;amp;amp;#x27;s modulus of the single fibre have been evaluated. It was established that both the tensile strength and the tensile

This study investigated the combined effect of cold rolling and heat treatment on the mechanical ... more This study investigated the combined effect of cold rolling and heat treatment on the mechanical properties of Al-Ti alloy. Samples of the alloy are cast in metal mould to obtain 0.94-2.19wt% mixes of titanium. These samples are grouped into untreated (as-cast) and those that are cold rolled to fifty percent reduction, homogenized at 500⁰C and soaked for one hour. The cold rolled and heat treated samples are normalized (<em>RT_n</em>) and quench-tempered (<em>RT_q-t</em>) at 100⁰C. All these samples are subjected to tensile, micro-hardness and microstructural evaluation. Results show remarkable improvement in the mechanical properties of the cold rolled and heat treated samples compared to the as-cast. In particular, the <em>RT_q-t</em> samples containing titanium in the range of 1.7-2.2% demonstrates improve tensile strength by 24.7%, y...

Journal of Electrochemical Science and Engineering, 2017

This study investigates the inhibition potential of Vernonia amygdalina stem extract (VAE) on the... more This study investigates the inhibition potential of Vernonia amygdalina stem extract (VAE) on the corrosion of mild carbon steel immersed in 1 M HCl solution containing various concentrations of the inhibitor. The corrosion rate and inhibition efficiency were evaluated using mass loss and adsorption techniques. The results revealed that VAE efficiently inhibits the corrosion rate of mild carbon steel immersed in the acidic medium. The concentration of 0.6 g/L provides the highest inhibition efficiency of 78.1 %. The adsorption process was consistent with the physisorption mechanism and obeyed the Langmuir isotherm. The functional groups responsible for inhibition were identified using Fourier-transformed infrared (FTIR) spectra. The surface morphology of the corroded samples examined with scanning electron microscopy (SEM) revealed the presence of protective oxide layer. Inhibition efficiency was found dependet on the presence of oxalate, phytate, tannins, saponins and flavonoids in the VAE. It has been concluded that VAE is safe, cheap and efficient corrosion inhibitor for mild carbon steel.

Journal of Minerals and Materials Characterization and Engineering, 2012

The effect of palm kernel shell on the microstructure and mechanical properties of recycled polye... more The effect of palm kernel shell on the microstructure and mechanical properties of recycled polyethylene (RLDPE) reinforced with palm kernel shell particulate composite was evaluated to assess the possibility of using it as a new material for engineering applications. The composites were produced by compounding and compressive moulding technique by varying the Palm kernel shell particle from 5-25 vol% with particles size of 150, 300 and 400 µm. The microstructure (SEM/EDS) and the mechanical properties of the composites were investigated. The hardness of the composite increases with increase in palm kernel shell content and the tensile strength of the composite increased to optimum of 5 vol%. Scanning electron Microscopy (SEM) of the composites surfaces indicates fairly interfacial interaction between the palm kernel shell particles and the RLDPE matrix. The composites produced with 150 µm particle size have the best properties of the entire grade. Hence this grade can be use for interior applications such as car seat, dash board, and car interior for decorative purposes or other interior parts of automobile where high strength is not considered a critical requirement.

Journal of Minerals and Materials Characterization and Engineering, 2013

This paper investigates the wear characteristic of grey cast iron composition under dry lubricati... more This paper investigates the wear characteristic of grey cast iron composition under dry lubrication conditions. The effects of sliding speed, applied load, time and percentage of ferrosilicon additions, on the wear rate of grey cast iron were studied. The set of experimental data were taken in a controlled and sequential manner. Scanning electron microscope was used to examine the morphology of the samples as well as the worn out surfaces. Linear regression equation and analysis of variances (ANOVA) showed that the main effect of silicon additions, load and speed variable are more pronounced on the wear behaviour of the grey cast iron. Also, the result showed that the additions of silicon improved the wear resistance of the grey cast iron as the wear parameters such as speed, load and time varied. The study showed that wear transition occurred at 3.2% silicon addition.

Journal of Minerals and Materials Characterization and Engineering, 2013

International Journal of Applied Ceramic Technology, 2020

The properties of carbon-containing refractories (CCRs) depend on the presence of carbon with fea... more The properties of carbon-containing refractories (CCRs) depend on the presence of carbon with features close to graphite. However, the thermosetting resins that are used to bind such refractories together during the initial preparation stage usually produce non-graphitic carbon when sintered, which can impair their overall performance. Based on this, ferrocene was used to induce graphitic carbon generation from a resole-type phenolic resin during a sequential carbonization operation. The resin formulation containing the graphitizing agent was then used to prepare resin-bonded Al2O3-MgO castables. The role of in situ graphitization of the modified binder on the properties such as cold crushing strength, apparent porosity, and oxidation resistance was examined. The results show that crystallization of the binder carbon can improve the castable oxidation resistance. At ambient temperature, no significant difference was observed in the samples&#39; physicomechanical properties. Nevertheless, holding time during the initial curing stage at 50°C played a significant role on those properties.

Int J Appl Ceram Technol., 2020

The properties of carbon-containing refractories (CCRs) depend on the presence of carbon with fea... more The properties of carbon-containing refractories (CCRs) depend on the presence of carbon with features close to graphite. However, the thermosetting resins that are used to bind such refractories together during the initial preparation stage usually produce non-graphitic carbon when sintered, which can impair their overall performance. Based on this, ferrocene was used to induce graphitic carbon generation from
a resole-type phenolic resin during a sequential carbonization operation. The resin formulation containing the graphitizing agent was then used to prepare resin-bonded Al2O3-MgO castables. The role of in situ graphitization of the modified binder on the properties such as cold crushing strength, apparent porosity, and oxidation resistance was examined. The results show that crystallization of the binder carbon can improve the castable oxidation resistance. At ambient temperature, no significant difference was observed in the samples' physicomechanical properties. Nevertheless, holding time during the initial curing stage at 50°C played a significant role on those properties.

Polypropylene (PP) composites with cellulose nanofibril (CNF), lignocellulose nanofibril (LCNF) o... more Polypropylene (PP) composites with cellulose nanofibril (CNF), lignocellulose nanofibril (LCNF) or bleached kraft wood pulp (BWKP) cellulose microfibril compatibilized by maleic anhydride grafted polypropylene were produced by different approaches. Samples containing 10-30 wt% filler were prepared by mixing cellulose aqueous suspensions and PP through solid-state shear pul-verization. The flakes obtained were compounded by twin-screw melt extru-sion (MSE) followed by injection molding (IM) into standard specimens. Reference samples with 30 wt% CNF or LCNF were prepared through a standard procedure, which involved freeze-drying of nanofibrils aqueous suspen-sions before MSE and IM, whereas a sample with 30 wt% BWKP was prepared directly by MSE and IM. Injection-molded specimens were characterized by scanning electron microscopy, differential scanning calorimetry, thermogravimetry, and tensile and notched impact tests. The thermal behavior of the PP matrix in the composites was not significantly affected by the filler type and content and processing route as well. CNF and LCNF reinforced PP composites showed inferior mechanical properties, due to the formation of nanofibrils agglomerates in the PP matrix, regardless of the processing route adopted. Highly filled (30 wt%) BWKP composites presented superior mechanical properties with significant increase in the modulus, tensile strength, and impact strength due to the formation of well-dispersed microfibrils bundles in the PP matrix. A comparative analysis showed that the composites developed in this study present similar or even superior mechanical performance for given filler content to other natural fiber reinforced PP composites reported in the literature. K E Y W O R D S bleached wood, cellulose nanofibrils, mechanical properties, polypropylene, solid-state shear pulverization

Environmental friendliness and cost demand the development of lignin-modified phenolic (LPF) resi... more Environmental friendliness and cost demand the development of lignin-modified phenolic (LPF) resins for application as a binder for carbon-containing refractories (CCRs) production. Moreover, the in-situ graphitization of such resins can produce crystalline carbon, which is an essential component of CCRs. Consequently, this study investigated LPF resins graphitization using ferrocene, boron oxide and boric acid. The modified resins were synthesized using thermally treated kraft lignin based on 1.5 formaldehyde to phenol molar ratio and with up to 30 wt.% lignin as phenol replacement. The resins chemical composition and the structural organization and oxidation resistance of carbons derived from the plain resins and those containing the graphitizing additives were determined. The results showed that ferrocene and the boron compounds could induce graphitic carbon generation when carbonizing LPF resins at 1500 °C for 5 hours. The best graphitization level (73%) was achieved when 10 wt.% boric acid was added to the resin produced with 20 wt.% lignin. Regarding the formulations containing ferrocene, the highest amount of graphitic carbon (48%) was generated when 5 wt.% of this additive was added to the resin synthesized with 10 wt.% lignin. The carbons derived from the formulations containing boron oxide presented the best oxidation resistance.

World Academy of Science, Engineering and Technology, 2014

This study investigated the combined effect of cold rolling and heat treatment on the mechanical ... more This study investigated the combined effect of cold rolling and heat treatment on the mechanical properties of Al-Ti alloy. Samples of the alloy are cast in metal mould to obtain 0.94-2.19wt% mixes of titanium. These samples are grouped into untreated (as-cast) and those that are cold rolled to fifty percent reduction, homogenized at 500 0 C and soaked for one hour. The cold rolled and heat treated samples are normalized (RT n) and quench-tempered (RT q-t) at 100 0 C. All these samples are subjected to tensile, micro-hardness and microstructural evaluation. Results show remarkable improvement in the mechanical properties of the cold rolled and heat treated samples compared to the as-cast. In particular, the RT q-t samples containing titanium in the range of 1.7-2.2% demonstrates improve tensile strength by 24.7%, yield strength, 28%, elastic modulus, 38.3% and micro-hardness, 20.5%. The Al 3 Ti phase being the most stable precipitate in the α-Al matrix appears to have been responsible for the significant improvement in the alloy's mechanical properties. It is concluded that quench and temper heat treatment is an effective method of improving the strength-strain ratio of cold rolled Al-.0.9-2.2%Ti alloy.

This study investigates the inhibition potential of Vernonia amygdalina stem extract (VAE) on the... more This study investigates the inhibition potential of Vernonia amygdalina stem extract (VAE) on the corrosion of mild carbon steel immersed in 1 M HCl solution containing various concentrations of the inhibitor. The corrosion rate and inhibition efficiency were evaluated using mass loss and adsorption techniques. The results revealed that VAE efficiently inhibits the corrosion rate of mild carbon steel immersed in the acidic medium. The concentration of 0.6 g/L provides the highest inhibition efficiency of 78.1 %. The adsorption process was consistent with the physisorption mechanism and obeyed the Langmuir isotherm. The functional groups responsible for inhibition were identified using Fourier-transformed infrared (FTIR) spectra. The surface morphology of the corroded samples examined with scanning electron microscopy (SEM) revealed the presence of protective oxide layer. Inhibition efficiency was found dependet on the presence of oxalate, phytate, tannins, saponins and flavonoids in the VAE. It has been concluded that VAE is safe, cheap and efficient corrosion inhibitor for mild carbon steel.

The effect of molybdenum on the morphological and wear behaviour of Nigeria Foundries grey cast i... more The effect of molybdenum on the morphological and wear behaviour of Nigeria Foundries grey cast iron (8) [NFgrey(8)] has been studied. The microstructural and mechanical properties of the cast samples for the control and the NFGrey(8)/Molybdenum alloy were characterised using SEM, XRD, Brinell Hardness and impact energy testing Machine respectively. MATLAB linear curve fitting technique was used to obtain the approximate linear equation via first differential approach. The results show that molybdenum addition improved significantly the wear resistance of the NFGrey(8) cast iron. However, the toughness of the alloy was sacrificed. The strong and hard intermetallic compounds within the matrix are attributable to wear resistance of the NFGrey(8)/Mo alloy.

International Journal of Metals, 2013

This paper examines the effects of heat treatment processes on the mechanical properties of as-ca... more This paper examines the effects of heat treatment processes on the mechanical properties of as-cast Al-4% Ti alloy for structural applications. Heat treatment processes, namely, annealing, normalizing, quenching, and tempering, are carried out on the alloy samples. The mechanical tests of the heat treated samples are carried out and the results obtained are related to their optical microscopy morphologies. The results show that the heat treatment processes have no significant effect on the tensile strength of the as-cast Al-4% Ti alloy but produce significant effect on the rigidity and strain characteristic of the alloy. With respect to the strain characteristics, significant improvement in the ductility of the samples is recorded in the tempered sample. Thus, for application requiring strength and ductility such as in aerospace industries, this tempered heat treated alloy could be used. In addition, the quenched sample shows significant improvement in hardness.

2014 International Conference on Interactive Collaborative Learning, Dec 1, 2014

The present state of engineering practices in our country has called for review of engineering cu... more The present state of engineering practices in our country has called for review of engineering curricula to make it more proactive and relevant to the industrial and societal needs. It is imperative that students be shown the difference between studying engineering and becoming an engineer. There is need for strong industrial interaction in our education for the students to know the types of problems engineers face, the concepts, processes, and tools they use to solve those problems, and the personal and professional attributes essential to be a team player in solving engineering problems. An attempt was made to evaluate all this variables in this paper.

2014 International Conference on Interactive Collaborative Learning (ICL), 2014

The present state of engineering practices in our country has called for review of engineering cu... more The present state of engineering practices in our country has called for review of engineering curricula to make it more proactive and relevant to the industrial and societal needs. It is imperative that students be shown the difference between studying engineering and becoming an engineer. There is need for strong industrial interaction in our education for the students to know the types of problems engineers face, the concepts, processes, and tools they use to solve those problems, and the personal and professional attributes essential to be a team player in solving engineering problems. An attempt was made to evaluate all this variables in this paper.

Journal of Minerals and Materials Characterization and Engineering, Aug 20, 2012

The morphology and mechanical properties of coconut shell reinforced polyethylene composite have ... more The morphology and mechanical properties of coconut shell reinforced polyethylene composite have been evaluated to establish the possibility of using it as a new material for engineering applications. Coconut shell reinforced composite was prepared by compacting low density polyethylene matrix with 5% -25% volume fraction coconut shell particles and the effect of the particles on the mechanical properties of the composite produced was investigated. The result shows that the hardness of the composite increases with increase in coconut shell content though the tensile strength, modulus of elasticity, impact energy and ductility of the composite decreases with increase in the particle content. Scanning Electron Microscopy (SEM) of the composites (with 0% -25% particles) surfaces indicates poor interfacial interaction between the coconut shell particle and the low density polyethylene matrix. This study therefore exploits the potential of agro-based waste fiber in Nigeria as an alternative particulate material for the development of a new composite.

This paper investigates the wear characteristic of grey cast iron composition under dry lubricati... more This paper investigates the wear characteristic of grey cast iron composition under dry lubrication conditions. The effects of sliding speed, applied load, time and percentage of ferrosilicon additions, on the wear rate of grey cast iron were studied. The set of experimental data were taken in a controlled and sequential manner. Scanning electron microscope was used to examine the morphology of the samples as well as the worn out surfaces. Linear regression equation and analysis of variances (ANOVA) showed that the main effect of silicon additions, load and speed variable are more pronounced on the wear behaviour of the grey cast iron. Also, the result showed that the additions of silicon improved the wear resistance of the grey cast iron as the wear parameters such as speed, load and time varied. The study showed that wear transition occurred at 3.2% silicon addition.

The effect of palm kernel shell on the microstructure and mechanical properties of recycled polye... more The effect of palm kernel shell on the microstructure and mechanical properties of recycled polyethylene (RLDPE) reinforced with palm kernel shell particulate composite was evaluated to assess the possibility of using it as a new material for engineering applications. The composites were produced by compounding and compressive moulding technique by varying the Palm kernel shell particle from 5 -25 vol% with particles size of 150, 300 and 400 µm. The microstructure (SEM/EDS) and the mechanical properties of the composites were investigated. The hardness of the composite increases with increase in palm kernel shell content and the tensile strength of the composite increased to optimum of 5 vol%. Scanning electron Microscopy (SEM) of the composites surfaces indicates fairly interfacial interaction between the palm kernel shell particles and the RLDPE matrix. The composites produced with 150 µm particle size have the best properties of the entire grade. Hence this grade can be use for interior applications such as car seat, dash board, and car interior for decorative purposes or other interior parts of automobile where high strength is not considered a critical requirement. A. J. OLUMUYIWA ET AL. 826 Plate 1. EDS/SEM morphology of the recycled polyethylene. A. J. OLUMUYIWA ET AL. 827 Plate 2. EDS/SEM morphology of the recycled polyethylene reinforced with 10 vol% at 150 µm size. Plate 3. EDS/SEM morphology of the recycled polyethylene reinforced with 25 vol%, 150 µm size. Plate 4. EDS/SEM morphology of the recycled polyethylene reinforced with 5 vol%, 300 µm size. A. J. OLUMUYIWA ET AL. 828 Plate 5. EDS/SEM morphology of the recycled polyethylene reinforced with 20%, 300 µm size. Plate 6. EDS/SEM morphology of the recycled polyethylene reinforced with 15 vol%, 400 µm size. Plate 7. EDS/SEM morphology of the recycled polyethylene reinforced with 25 vol%, 400 µm size.