Publications 2024
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PublicationImproved solar cell efficiency of titanium dioxide on porous silicon using pulsed laser deposition at different laser wavelengths( 2024-01-01)In this study, a Q-switched Nd:YAG laser with specific parameters, including a pulse repetition rate of 6 Hz, a pulse duration of 10 nm, a wavelength of 532 nm, and a laser fluence of 237.47 J cm−12, was employed to fabricate highly crystalline TiO2 nano-films. These nano-films exhibited a narrow energy band gap of 3.24 eV and showcased favorable surface morphology, characterized by a roughness of 2.38 nm. A solar cell device was produced by creating porous silicon (PSi) and applying titanium dioxide films onto the PSi, achieving a notable conversion efficiency of 8.733%. To investigate the impact of different parameters on the resulting TiO2 nano-films, a range of laser fluences (ranging from 131.93 to 263.85 J cm−12) and three distinct laser wavelengths (1064 nm, 532 nm, and 355 nm) were employed during the pulsed laser deposition (PLD) process. These experiments aimed to grow TiO2 films on both quartz and silicon (Si) substrates.
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PublicationCyclic and differential pulse voltammetric measurements on fibrils formation of alpha synuclein in Parkinson's disease by a gold interdigitated tetraelectrodes( 2024-01-01)Parkinson's disease is a neurodegenerative disorder characterized by the aggregation and deposition of alpha-synuclein protein, which are pathological hallmarks. To understand the fibril formation of alpha-synuclein in Parkinson's disease, this study uses cyclic and differential pulse voltammetric measurements. These measurements analyze the electrochemical properties and behavior of alpha-synuclein during its fibril formation process. By applying a potential sweep or pulse to the alpha-synuclein sample, it is possible to gain insights into its redox activity and structural changes during fibril formation. This could lead to the development of therapeutic strategies to prevent or disrupt this pathological event in Parkinson's disease. To detect Parkinson's disease, a 15 nm sized gold conjugated antibody was used as the probe and seeded on gold interdigitated tetraelectrodes (AuIDTE). Alpha synuclein variations (fibriled and non-fibriled) were detected using phosphate-buffer saline and glycine buffer based on cyclic voltammetry and differential pulse voltammetry techniques. Discriminated by Tau protein measurement that was employed as a control. The linear regression for detecting alpha synuclein aggregation using differential pulse voltammetry was R2 = 0.9987 [y = 9E-06x - 4E-07], with a limit of detection of 10 aM, on a linear range of 1 aM-1 pM. Cyclic voltammetry determined the limit of detection of aggregated alpha synuclein to be 100 aM, with a linear relationship of R2 = 0.9939 [y = 7E-06x - 2E-06]. The sensor has excellent analytical performance in terms of detection limit, sensitivity, selectivity, repeatability, and stability.
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PublicationSodium alginate/hydroxyapatite/graphene nanoplatelets composites for bone tissue engineering( 2024-01-01)Sodium alginate (SA)/hydroxyapatite (HA)/graphene nanoplatelets (GP) bionanocomposite films that possess good biocompatibility for bone tissue engineering are prepared by a simple solution casting process. The prepared nanocomposite films are analyzed by XRD, SEM, EDAX, and FTIR analyses. XRD confirms the presence of hydroxyapatite and graphene nanoplatelets in the nanocomposite. FTIR spectrum confirms the interaction between the matrix and the fillers. The morphology of the fillers and nanocomposite films are observed through SEM images. The inclusion of GP with different concentrations into the biopolymer film improves the tensile strength. As a result, the loading of 0.5 wt% of graphene and 10 wt% of HA in the SA polymer shows high tensile strength when compared to the pure SA and SA filled with HA. Tensile strength gradually decreases when the loading of graphene is increased to 2.5% and 5% in the bionanocomposite film. The tensile strength of the bionanocomposite film with 10% of hydroxyapatite is increased by 17%, whereas the tensile strength of the bionanocomposite film loaded with 10% of hydroxyapatite and 0.5% graphene is increased by 99%. Biological tests, such as swelling, biodegradation tests, and biomineralization tests, confirm the biocompatibility of the nanocomposite films.
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PublicationThermal behaviour of graphene nanoplatelets and multiwalled carbon nanotubes filled-glass fibre-reinforced epoxy composites( 2024-01-01)The effects of thermal behaviour on graphene nanoplatelets (GP) and multiwalled carbon nanotube (CN) nanofillers of glass fibre (GL)-reinforced epoxy composites were investigated. The paper aims at evaluating, through a single and hybrid carbon-based nanofiller on the thermal stability, mechanical properties, electromechanical properties at elevated temperature, and morphologies of the composites. The nanofillers were dispersed using a mechanical stirrer, Thinky mixer, and ultrasonic probe. Hand lay-up and vacuum bagging techniques were used in the manufacturing of composites. Real-time self-monitoring of the structural damage to the specimens under tensile and flexural tests was performed through electromechanical measurements. Using the GP–CN hybrid in the composite improved the adhesion between the hybrid nanofillers and matrix. The thermal properties of GP–GL, CN–GL, and GP–CN–GL hybrid composites increased with the hybrid nanofiller addition. Mechanical testing at elevated temperatures revealed a higher rate of strength degradation for the 1.5-mass% GP–CN–GL hybrid composite than for a single nanofiller composite. The GP–CN–GL hybrid composites exhibited a more pronounced nonlinear behaviour and lower resistance.
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PublicationEffect of varying core density and material on the quasi-static behaviors of sandwich structure with 3D-printed hexagonal honeycomb core( 2024-01-01)Additive manufacturing (AM) involves the development of complex, lightweight sandwich structures for the automotive and aerospace industries. These structures are essential for load bearing and impact resistance. Nevertheless, there is a significant obstacle of failure under compressive loading, e.g. through brittle fractures and crushing. To address this issue, this study evaluates the compressive properties, energy absorption and failure damage in quasi-static tests (flatwise, in-plane, and flexural) of sandwich composites with 3D-printed hexagonal honeycomb cores of different unit cells (6, 8 and 10 mm) and materials (polylactic acid (PLA), PLA-Carbon and PLA-Wood). The results show that increasing the core density enhances compressive strength, modulus, and energy absorption. An 8 mm unit cell absorbs energy optimally for lightweight structures. In PLA flatwise testing, the 8 mm unit cell absorbed 419.49 J more energy than the 10 mm unit cell. Additionally, PLA-Wood has better mechanical performance than PLA-Carbon due to the better filler with the PLA- matrix. In flatwise testing with an 8 mm unit, PLA-Wood absorbs 214.01 J, while PLA-Carbon absorbs 122.49 J. The failure modes vary depending on tests performed. The study highlights the potential of 3D-printed honeycomb core structures for load-bearing applications in various industries, including aerospace and automotive. Highlights: Quasi-static loading behavior of 3D-printed hexagonal honeycomb cores. Increased core density improves compressive stress, modulus, and absorbed energy. An optimal unit cell size for lightweight 3D printed core structures is 8 mm. PLA-Wood performs better in energy absorption due to filler compatibility. The failure modes are related to the type of quasi-static loads applied.