Carbon fiber reinforced polymers (CFRP) are characterized by their impressive specific strength. These lightweight composites are increasingly replacing metals and glass fiber reinforced polymers (GFRP). Key advantage of CFRP is its inherent resistance property to environmental degradation, making them promising candidates for corrosion-resistant applications. Engineering structures frequently experience cyclic loading conditions, which can lead to their failure and damage. Numerous research findings indicate that the performance of CFRP composites under fatigue is significantly influenced by various factors such as material composition, environmental impact, and the applied cyclic loads. The nature of composite fatigue involves the complex process of crack initiation and propagation. The damage mechanism of CFRP composite is challenging due to the material inhomogeneity and variations in constituent materials, service and cyclic loading conditions. This review paper aims to present the most relevant data regarding CFRP’s fatigue behaviour.
Aluminium alloy 6063-T6 is a popular choice among different industrial sectors as it portrays various desirable properties like moderate strength, improved corrosion resistance, better weldability and formability etc. These advantages make AA6063-T6 a common choice for matrix in a metal matrix composite. Mostly conventional fusion welding methods like Metal Inert Gas (MIG) and Tungsten Inert Gas (TIG) seem preferable options for welding aluminium and its alloys but it remains a challenge to use them to weld aluminium metal matrix composite. A modified version of MIG i.e. CMT welding, can be explored to overcome the challenges. In this study, an aluminium metal matrix composite has been fabricated with AA6063-T6 as matrix and two reinforcements −one organic, i.e., Eggshell (ES) and one inorganic, i.e., Boron Carbide (B4C), using the conventional stir casting method. CMT welding has been performed on plates cut out from the composites. Microstructure, hardness, tensile strength and residual stress of weld joint of composite have been observed. From micrographs, it is observed that a finer grain has been formed at the Fusion Zone (FZ) in comparison to the Heat Affected Zone (HAZ) and Parent Material (PM). XRD analysis at the fusion line has identified several intermetallic stoichiometric compounds (Al12Mg17, Mg2Si, CaMgSi, CaO, B2O3) and reinforcement B4C and CaCO3 within the matrix volume. The FZ exhibits higher hardness than the HAZ and the PM. Further, the tensile strength of the FZ exceeds that of the unwelded composite due to the presence of metastable strengthening phases of Mg2Si in the FZ, along with reinforcement (B4C and ES) particles. Residual stress analysis reveals tensile stress in the FZ and more compressive stress in the HAZ than in the PM.
While silicon-based electronic devices exhibit high performance, they lack the flexibility required for the development of flexible devices. The need for flexible devices has sparked research interest in organic semiconductors, primarily due to their lightweight nature, cost-effectiveness, and suitability for large-scale applications. Organic field-effect transistors (OFETs) are crucial in advancing the development of bendable smart cards, expansive displays, healthcare sensors, and various other applications. This study explores the structural and optical properties of the organic semiconductor layer, poly (3-hexylthiophene-2, 5-diyl) (P3HT), and the dielectric layer, graphene oxide (GO), with the aim to incorporating them into OFETs. Field Emission Scanning Electron Microscopy (FESEM) reveals the smooth surface morphology of both the P3HT and GO semiconductor layers, facilitating efficient charge transport at the dielectric-semiconductor interface. X-ray Diffraction (XRD) characterization indicates the amorphous nature of both the P3HT and GO layers. Furthermore, Raman spectra of GO demonstrate an ID/IG ratio of 0.91, indicating the presence of defects in the dielectric material. Additionally, the electrical characteristics of the fabricated device exhibit Schottky behaviour.
A cytocompatible silica-zinc catalyst from cow dung for photocatalytic reduction of Chromium (VI) to Chromium (III) was prepared by sol-gel method with zinc nitrate and the sodium silicate solution prepared from the cow dung ash. The catalyst was characterised by X-Ray Diffraction (XRD) analysis, which indicated the Opaline form (Opal-C) of silica. This result was further corroborated in the Infrared (IR) spectrum. Silicon, Sodium, and Zinc were confirmed using an energy-dispersive spectrum, and the surface morphology indicated agglomerated particles and hollow tubular structures of different dimensions in the Field emisson scanning electron microscopy (FE-SEM). The direct band gap of 4.9 eV was calculated from diffuse reflectance studies. The Chromium (VI) to Chromium (III) reduction was analysed by DPC complexation and absorbance at 540 nm in a UV–visible spectrophotometer. MTT assay test proved that the composite is cytocompatible with more than 50 % cell viability even at higher concentrations like 100 µg/mL.
This research paper presents a comprehensive study on the comparison of three distinct corner manufacturing techniques in sheet metal forming: close corner, open corner, and open corner with a corner relief notch. The investigation primarily focuses on assessing crack presence, crack propagation behaviour, and structural integrity of the corner samples through visual inspection and scanning electron microscope (SEM) analysis. Visual inspection revealed the presence of cracks in the close corner sample, whereas both open corner samples exhibited crack-free surfaces. SEM analysis uncovered micro cracks at the tip of the existing crack in the close corner sample, while the open corner sample showcased a micro crack at the lower fibre. Notably, the upper fibre of the close corner sample remained defect-free. In contrast, the open corner sample with a corner relief notch exhibited an absence of cracks altogether. To evaluate real-world application feasibility, a circuit breaker mounting pan for a switchboard was designed using the three corner types. Static analysis was conducted to assess the structural performance of each corner pan. Results indicated that the stresses in the close corner pan remained below the yield strength, ensuring structural stability. Conversely, stresses in both open corner pans, with and without a corner relief notch, exceeded the yield strength, posing concerns for their practical use. Interestingly, the open corner pan with a corner relief notch demonstrated stress patterns similar to its counterpart without the notch.
