We report the spectroscopic, thermal, and mechanical outcomes of epoxy reinforced sisal/flax (S/F) hybrid natural fiber composites. This work is intended to enhance the mechanical and thermal properties of the sisal fibers in addition to flax fibers. In recent years, natural fiber composites gained inclusive credit as a supernumerary to conventional synthetic composites for their superior ecological properties. Five different varieties of composite slabs i.e., 60% epoxy matrix and 40% of sisal/flax fibers were fabricated unidirectionally through a simple hand layout method by varying sisal and flax ratio as (40/0, 30/10, 20/20, 10/30, and 0/40) with a constant weight fraction as 0.4W _f . The x-ray diffraction analysis was performed on the 20 S/20 F specimen and the crystallinity index is calculated as 42.84%. The spectroscopic and thermal studies were conducted on the 20 S/20 F sample and the chemical imprint of the composite is revealed by the strong peaks of cellulose, hemicellulose, and lignin along with amorphous and crystalline content of the FTIR data and is confirmed through the XRD data. The addition of flax fibers to sisal fibers showed a constructive improvement of thermal stability which is shown by the TG/DTA graph. In a three-stage degradation of sample, a maximum is observed at 334 °C. The tensile, flexural, and impact tests of all the fabricated composite samples are performed and ultimate tensile strength of 165.2 N/mm ² for the 40 S/0 F composite with an elongation of 9.2% is noted. The ultimate flexural stress of 8.1 N mm ⁻² is observed in composite 10 S/30 F and composite 10 S/30 F has an excellent ability to absorb impact force of 1.2 J energy. Based on the above results the manufactured composites exhibited higher thermal and mechanical properties showing a unique characteristic for different concentrations of flax fibers. Thus, the developed composites can be used individually for various applications based on the requirement of the end-user.

Covid-19 still remains as global pandemic surging with different variants like alpha, beta, gamma, delta and most omicronin various countries resulted into SARS-CoV-2. An escalation in random testing for Covid-19 is considered as golden standard by World Health Organization (WHO) to control the spread of Corona virus. RT-PCR and nucleic acid hybridization strategies are the two highly sensitive outstanding tests used for the detection of SARS-CoV-2 in the DNA by the former and RNA/DNA by the later. Apart from the test for virus, antigen and antibodies other alternative hematological tests like CRP, Ferritine, IL-6, Blood Platelets and WBC and plasma became essential for the detection and management of Covid-19. Overcoming the limitations a rapid, efficient, low-cost and easy-to-implement test kits are in imperative need to meet the requirement. Electrochemical sensors are considered as potential, ultra-fast and point-of-care sensors used as self-testing kits. In this work, a meta review of various modified electrodes with different nanomaterials such as graphene, CNTs, and nano-dopants used as electrochemical sensors in association with testing various different parameters for detection of Covid-19. A detailed discussion on the merits and demerits of present testing patterns and scope of screen-printed electrochemical sensors modified with different nanomaterials and their advantages are presented.

In the present work, we report the fabrication, spectroscopic, and mechanical properties of the novel f-MWCNTS/g-C ₃ N ₄ /TiO ₂ (MGT-NCs) metal-free ternary nanocomposite reinforced denture base PMMA. The functionalised-MWCNTs were introduced into the graphitic carbon nitride (g-C ₃ N ₄ ) nanopowders (NPs). The obtained high porous f-MWCNTS/g-C ₃ N ₄ NPs were mixed with 10 wt% of TiO ₂ NPs previously hydrothermally synthesized. These prepared powders were characterized by XRD, FE-SEM, HR-TEM, FT-IR, and Raman spectroscopy to study the crystal structure and morphology. Using a mechanical blender 2 wt% of g-C ₃ N ₄ , MWCNT/g-C ₃ N ₄ , and MGT-NCs were sintered into PMMA heat-activated denture base polymer powder and mixed with monomer to fabricate the composites through heat curing. Three different varieties of composite specimens were prepared into flexural, impact, compression, and hardness testing standards. From the comparative assessment of results, it is found that novel MGT-NCs reinforced PMMA exhibited superior mechanical properties. The surface morphology of the fractured and compressed specimens was studied using the SEM analysis and found to have dimples and increased roughness compared to the pristine PMMA and g-C ₃ N ₄ , MWCNT/g-C ₃ N ₄ . Hence, the fabricated novel metal-free MGT-NCs can be used as a reinforcement material in PMMA denture bases to achieve a concurrent enhancement in both physical and mechanical properties.