Papers by Temitope Olugbade
Pulse compression is an important and burning issue in radar signal processing. In the recent pas... more Pulse compression is an important and burning issue in radar signal processing. In the recent past, many adaptive and neural network based methods have been proposed to achieve effective pulse compression performance for real coded transmitted waveforms. Even though the radar signal is complex, it is mostly processed as real-valued in-phase and quadrature components. Hence it is desirable that for processing complex radar signal for pulse compression both the structure as well as the learning algorithm associated with it need to be complex in nature. Accordingly in this paper a novel adaptive method is proposed by employing a complex valued fully connected cascaded (CFCC) neural network. For training this network, a new complex Levenberg-Marquardt (CLM) algorithm is derived and used for imparting effective training of its weights. The new CLM based CFCC (CFCC-CLM) model offers superior convergence performance with the least residual mean squared error during training phase compared to those provided by the multilayer perceptron (MLP) trained with complex domain backpropagation (CDBP) and CLM based methods. Further the comparison of peak signal-to-sidelobe ratio (PSR) under noisy and Doppler shift conditions of the proposed method exhibits best performance compared to those offered by the MLP-CDBP, MLP-CLM and the matched filter (MF) based methods.
Materials Science and Technology, Aug 12, 2022
Analytical Letters, Jul 20, 2020
Abstract Upgrading the corrosion properties of metallic materials has been the dream of many corr... more Abstract Upgrading the corrosion properties of metallic materials has been the dream of many corrosion experts and material scientists. The present study investigated the influence of mechanical deformation by rolling process on the corrosion behavior of mild steel through an electrochemical process in a chloride-containing environment at room temperature. The microstructures before and after rolling and corrosion tests were analyzed by scanning electron microscopy (SEM). The mild steels were first subjected to cold rolling with approximately 30% rolling reduction, and the corrosion resistance of both the unrolled and rolled samples was then determined. The polarization results revealed that the rolled mild steel sample possessed a corrosion potential of −0.118 V, reduced corrosion current density of 0.133 mA/cm2, higher impedance, and phase angle maximum. The grain refinement and the surface roughness are related to the deformation and corrosion mechanisms.
World Journal of Engineering, Jan 20, 2020
Biomedical engineering, Jun 14, 2023
Additive manufacturing (AM) is the opposite of conventional manufacturing technologies, creating ... more Additive manufacturing (AM) is the opposite of conventional manufacturing technologies, creating an opportunity to fabricate parts using a layer upon layer approach to obtain 3D patterns. AM technology has provided an opportunity for biomaterials usage in the bio-fabrication of organs and scaffolds for tissues engineering. In recent times, AM has been well-utilized for the printing of organs, customized implants, anatomical models for surgery training kits, drug formulations, prosthetics, orthotics, dentistry, and scaffolds for tissue engineering with the use of metals, ceramics, polymers, and composites materials. Printing of biomaterial that has a suitable viscosity, enough strength, good biocompatibility, and degradability has been reported by many researchers to be an arduous task. Biomaterials printed with robust mechanical properties are considered highly essential for the fabrication of soft tissues such as cartilage and skin because the function of such tissues mainly relies on their mechanical properties that possess the capacity to support cell proliferation and extracellular matrix production. For repairing and regenerating organs or tissue, the implant must provide sufficient mechanical support to endure in vivo stresses and load-bearing cycles. This book chapter aims to document the mechanical properties of 3D printed biomaterials and provides a keys future research direction.
Materials Science and Technology, Mar 11, 2022
Wire and arc additive manufacturing (WAAM) is the most advanced technique used to fabricate desir... more Wire and arc additive manufacturing (WAAM) is the most advanced technique used to fabricate desired parts by depositing material in layer-by-layer sequence. WAAM can produce medium and large sized components with higher deposition rates, low manufacturing cost and less production time. Mechanical and metallurgical properties of WAAM based products are much better and suited for aerospace engineering. WAAM is still under examination because of challenges like porosity, corrosion, delamination, residual stresses and oxidation. From the literature review, it has observed that the metals like titanium, aluminum, steels & nickel alloys can be used in WAAM process. In this paper, the various technologies and process advancements such as inter pass cold rolling, inter pass cooling, peening effect and weld pool oscillation have been discussed in detail. Finally, an in depth about WAAM of aluminum alloys and metallurgical and mechanical properties have been discussed. Based on the above review, various problems associated with WAAM of aluminum alloys and the strategies to address the issues are presented.
Metals and Materials International, Mar 4, 2023
Burning rate determines the rate at which a certain mass of fuel is combusted in air. This study ... more Burning rate determines the rate at which a certain mass of fuel is combusted in air. This study was conducted to investigate the effect of compaction pressure, binder proportion and particle size on the burning rate of fuel briquettes produced from a mixture of rice bran and palm kernel shell. This study involved three particle sizes of rice bran and palm kernel shell briquette at levels 2.0, 4.0 and 6.0 mm, compaction pressure at levels 3.0, 5.0, 7.0 and 9.0 MPa with cassava starch used as binder in the ratio of 10, 20, 30, 40 and 50% by weight. Tests showing the effects of binder level, particle sizes and compaction pressure on the burning rate of the briquette were carried out. The burning rate resulted into 2.3, 2.0, 1.9, 1.7 and 1.6 g/min at binder level of 10, 20, 30, 40 and 50 % respectively. It could be concluded that increased in compaction pressure, binder ratio and decreased in particle size caused decrease in the burning rate of the briquettes.
An adjustable multi nut tighter or remover for car tyre (with 114.3 PCD) was developed. The need ... more An adjustable multi nut tighter or remover for car tyre (with 114.3 PCD) was developed. The need to loosen and tighten car wheel nuts with little application of force (torque) and time spent is of great importance to most car users. Operation with the existing common instruments like ratchet, socket and impact wrench is quite tedious and time consuming. This study was aimed at designing and fabricating a device that will remove and tighten four-wheel nuts of car tyre simultaneously. The design was done using Solidworks CAD software. The device was successfully fabricated, and performance evaluation was carried out. The tightening and loosening of nuts were done with ease as evident from the results obtained. From the performance evaluation of the developed machine, it took 65 seconds to loosen four nuts and 75 seconds to tighten the nuts and the loosening and tightening process were reduced by 41% and 38% respectively compared to using L shaped wrench. Ergonomics consideration was put in place in designing this device as it can be used with ease by both man and woman. The device is also easy to maintain, easy to handle and able to remove and tighten four-wheel nuts of car tyre at once.
Bioresource Technology Reports
3D Printing and Additive Manufacturing
International Journal of Material Science Innovations, 2015
Chemistry Africa, 2023
Aluminium alloys are materials of choice for structural applications with remarkable mechanical a... more Aluminium alloys are materials of choice for structural applications with remarkable mechanical and corrosion properties but prone to premature failure under the combined action of stress and corrosive environment. Over the years, several efforts including surface modifications and thermomechanical treatments have been made to address this shortcoming. The present work reviews the corrosion, stress corrosion cracking (SCC), and corrosion fatigue (CF) behaviour of nanostructured Al alloys especially the Al–Mg (5xxx-series) and Al–Zn–Mg (7xxx-series), after surface modifications. To a large extent, the SCC behaviour of Al alloys could be influenced by the microstructure, heat treatments, stress, pre-strain, alloy compositions, and environments. The CF properties of surface-modified Al alloys were reviewed with a view to finding a relation between the nanostructured Al alloys and their aftermath corrosion fatigue properties. The fatigue behaviour of Al alloys can be influenced by the corrosion behaviour via various mechanisms including hydrogen embrittlement, prompt crack growth in aggressive environment, and crack initiation at pits. The strengthening mechanisms in nanostructured Al alloys are also briefly explained. For further study, some insights are then provided to avail the readers on options for future research.
MRS Advances
The electrochemical properties of the passive flm formed on surface-modifed 301 stainless steel (... more The electrochemical properties of the passive flm formed on surface-modifed 301 stainless steel (SS) were examined in the present study. After surface treatment, the passive flm analysis was carried out via X-ray photoelectron spectroscopy (XPS) technique, while the surface microstructure of the samples was examined by scanning electron microscope analysis. With Cr 2p, Fe 2p, O 1s, Ni 2p, and C 1s as the principal spectra in the passive flm, the Cr 2p spectrum shows two major peaks at 574.3 eV and 583.8 eV corresponding to Cr 2p3/2 (Cr in the metallic state) and Cr 2p1/2, respectively. The Fe 2p spectrum has two major peaks of 707.1 and 720.1 eV corresponding to Fe 2p3/2 (Fe in metallic state) and Fe 2p1/2 peaks, respectively, while the binding energies of 853.3 and 875.1 eV for the Ni 2p spectrum correspond to nickel in the metallic state. The XPS spectra revealed a higher percentage of Cr in the passive film of the treated 301 SS when compared with other elements. From the polarization results, the treated 301 SS possessed a lower corrosion current density of 1.401 mA/cm2 and higher corrosion potential of − 0.085 V.
MRS Advance, 2022
The electrochemical properties of the passive flm formed on surface-modifed 301 stainless steel (... more The electrochemical properties of the passive flm formed on surface-modifed 301 stainless steel (SS) were examined in the
present study. After surface treatment, the passive flm analysis was carried out via X-ray photoelectron spectroscopy (XPS)
technique, while the surface microstructure of the samples was examined by scanning electron microscope analysis. With
Cr 2p, Fe 2p, O 1s, Ni 2p, and C 1s as the principal spectra in the passive flm, the Cr 2p spectrum shows two major peaks
at 574.3 eV and 583.8 eV corresponding to Cr 2p3/2 (Cr in the metallic state) and Cr 2p1/2, respectively. The Fe 2p spectrum
has two major peaks of 707.1 and 720.1 eV corresponding to Fe 2p3/2 (Fe in metallic state) and Fe 2p1/2 peaks, respectively,
while the binding energies of 853.3 and 875.1 eV for the Ni 2p spectrum correspond to nickel in the metallic state. The XPS
spectra revealed a higher percentage of Cr in the passive film of the treated 301 SS when compared with other elements. From the polarization results, the treated 301 SS possessed a lower corrosion current density of 1.401 mA/cm2 and higher corrosion potential of − 0.085 V.
Chemistry Africa, 2022
The surface analysis of the passivation film formed on surface-deformed AISI 304 stainless steel ... more The surface analysis of the passivation film formed on surface-deformed AISI 304 stainless steel was carried out in the present study, and its corrosion properties were also determined. The morphology of the surface layer and the phase identification
before and after surface modification were examined via scanning electron microscope (SEM) and X-ray diffraction (XRD) techniques, respectively. The composition of the resulting passive film as well as Cr distribution as a function of sputter depth was characterized by the X-ray photoelectron spectroscopy (XPS) method. The XPS spectra revealed the existence of Cr, Fe, O, Ni, and C as the principal elements in the resulting passive films formed on the treated 304 steel sample with a high percentage of Cr at the top surface layer. Compared to the untreated sample, the potentiodynamic polarization tests revealed that the treated sample exhibited a better corrosion behavior in terms of higher corrosion potential, lower corrosion current density, and higher impedance.
Journal of Materials Science & Technology, 2020
Comparison of modified injection molding and conventional machining in biodegradable behavior of ... more Comparison of modified injection molding and conventional machining in biodegradable behavior of perforated cannulated magnesium hip stents,
Nano Materials Science, 2020
Most of the challenges experienced by many engineering materials originate from the surface which... more Most of the challenges experienced by many engineering materials originate from the surface which later leads to total failure, hence affecting the resultant mechanical properties and service life. However, these challenges have been addressed thanks to the invention of a novel surface mechanical attrition treatment (SMAT) method which protects the material surface by generating a gradient-structured layer with improved strength and hardness without jeopardizing the ductility. The present work provides a comprehensive literature review on the mechanical properties of materials after SMAT including the hardness, tensile strength and elongation, and residual stress. Firstly, a brief introduction on the different forms of surface nanocrystallization is given to get a better understanding of the SMAT process and its advantages over other forms of surface treatments, and then the grain refinement mechanisms of materials by SMAT from the matrix region (base material) to the nanocrystallized layer are explained. The effects of fatigue, fracture, and wear of materials by the enhanced mechanical properties after SMAT are also discussed in detail. In addition, the various applications of SMAT ranging from automotive, photoelectric conversion, biomedical, diffusion, and 3D-printing of materials are extensively discussed. The prospects and recent research trends in terms of mechanical properties of materials affected by SMAT are then summarized.
Advanced Engineering Materials, 2019
AISI 301 stainless steel (SS) is known for its high strength and hardness but tends to be less co... more AISI 301 stainless steel (SS) is known for its high strength and hardness but tends to be less corrosion resistant for many applications. Several attempts have been made in the past to investigate its corrosion behavior by different methods. However, current knowledge is insufficient on its corrosion resistance when subjected to surface treatment. In this work, a new route to enhance the corrosion resistance of nanostructured 301 SS using surface mechanical attrition treatment (SMAT) method is described. SMAT improves the mechanical properties of 301 SS by the formation of a nanostructure layer on the material surface. Compared to the as-received 316 and 304 SS counterparts, the present nanostructured 301 SS exhibits an improved corrosion behavior by a lower corrosion current density (1.308 mA/cm 2), higher corrosion potential (À0.071 V), higher phase angle and impedance, better charge-transfer resistance, and Cr content. The improved corrosion resistance can be attributed to the ability of SMAT to facilitate the move of Cr on the surface, which forms a stronger passivation layer with a new mechanism of passivation that may save a lot of noble metals.
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Papers by Temitope Olugbade
present study. After surface treatment, the passive flm analysis was carried out via X-ray photoelectron spectroscopy (XPS)
technique, while the surface microstructure of the samples was examined by scanning electron microscope analysis. With
Cr 2p, Fe 2p, O 1s, Ni 2p, and C 1s as the principal spectra in the passive flm, the Cr 2p spectrum shows two major peaks
at 574.3 eV and 583.8 eV corresponding to Cr 2p3/2 (Cr in the metallic state) and Cr 2p1/2, respectively. The Fe 2p spectrum
has two major peaks of 707.1 and 720.1 eV corresponding to Fe 2p3/2 (Fe in metallic state) and Fe 2p1/2 peaks, respectively,
while the binding energies of 853.3 and 875.1 eV for the Ni 2p spectrum correspond to nickel in the metallic state. The XPS
spectra revealed a higher percentage of Cr in the passive film of the treated 301 SS when compared with other elements. From the polarization results, the treated 301 SS possessed a lower corrosion current density of 1.401 mA/cm2 and higher corrosion potential of − 0.085 V.
before and after surface modification were examined via scanning electron microscope (SEM) and X-ray diffraction (XRD) techniques, respectively. The composition of the resulting passive film as well as Cr distribution as a function of sputter depth was characterized by the X-ray photoelectron spectroscopy (XPS) method. The XPS spectra revealed the existence of Cr, Fe, O, Ni, and C as the principal elements in the resulting passive films formed on the treated 304 steel sample with a high percentage of Cr at the top surface layer. Compared to the untreated sample, the potentiodynamic polarization tests revealed that the treated sample exhibited a better corrosion behavior in terms of higher corrosion potential, lower corrosion current density, and higher impedance.
present study. After surface treatment, the passive flm analysis was carried out via X-ray photoelectron spectroscopy (XPS)
technique, while the surface microstructure of the samples was examined by scanning electron microscope analysis. With
Cr 2p, Fe 2p, O 1s, Ni 2p, and C 1s as the principal spectra in the passive flm, the Cr 2p spectrum shows two major peaks
at 574.3 eV and 583.8 eV corresponding to Cr 2p3/2 (Cr in the metallic state) and Cr 2p1/2, respectively. The Fe 2p spectrum
has two major peaks of 707.1 and 720.1 eV corresponding to Fe 2p3/2 (Fe in metallic state) and Fe 2p1/2 peaks, respectively,
while the binding energies of 853.3 and 875.1 eV for the Ni 2p spectrum correspond to nickel in the metallic state. The XPS
spectra revealed a higher percentage of Cr in the passive film of the treated 301 SS when compared with other elements. From the polarization results, the treated 301 SS possessed a lower corrosion current density of 1.401 mA/cm2 and higher corrosion potential of − 0.085 V.
before and after surface modification were examined via scanning electron microscope (SEM) and X-ray diffraction (XRD) techniques, respectively. The composition of the resulting passive film as well as Cr distribution as a function of sputter depth was characterized by the X-ray photoelectron spectroscopy (XPS) method. The XPS spectra revealed the existence of Cr, Fe, O, Ni, and C as the principal elements in the resulting passive films formed on the treated 304 steel sample with a high percentage of Cr at the top surface layer. Compared to the untreated sample, the potentiodynamic polarization tests revealed that the treated sample exhibited a better corrosion behavior in terms of higher corrosion potential, lower corrosion current density, and higher impedance.