Browsing by Author "Afzal, Ali"
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- ItemCharacterization and antibacterial property of Kapok fibers treated with chitosan/AgCl-TiO2 colloid(TAYLOR & FRANCIS LTD, 2-4 PARK SQUARE, MILTON PARK, ABINGDON OR14 4RN, OXON, ENGLAND, 2019-01-02) Hai, Abdul Moqeet; Ahmed, Mehboob; Afzal, Ali; Jabbar, Abdul; Faheem, SajidThe aim of this research is to investigate the antibacterial activity of Kapok fibers modified with AgCl/TiO2 and Chitosan colloid. A very simple, single-step (pad-dry-cure) method was used for the application of AgCl/TiO2 and Chitosan colloid on kapok fibers, the chemicals used are easily available. Different blend ratios of chitosan and AgCl/TiO2 colloid were applied to the bleached kapok fibers and antibacterial properties were assayed against gram positive (Staphylococcus aureus) and Gram-negative (Escherichia coli) bacteria. The treated kapok fibers were characterized by Fourier Transform Infrared Spectroscopy (FTIR), X-ray Diffraction (XRD) and Scanning Electron Microscopy (SEM). It was observed that the bacterial growth was significantly reduced in the samples which had a higher concentration of chitosan and AgCl/TiO2 colloid. However, a significant reduction in bacterial growth with the use of this colloid was observed.
- ItemStealth technology: Methods and composite materials—A review(John Wiley and Sons Inc., 2019) Ahmad, Husnain; Tariq, Asra; Shehzad, Amir; Faheem, Muhammad S; Shafiq, Muhammad; Rashid, Iqra A.; Afzal, Ayesha; Munir, Adnan; Riaz, Muhammad T.; Haider, Hafiz T.; Afzal, Ali; Qadir, Muhammad B.; Khaliq, ZubairComposites have revolutionized the field of aeronautics with its intriguing properties including high strength to weight ratio, low weight, chemical and weather resistance, flexible design and low cost of installation. Also, composites are used as radar absorbing materials (RAMs) in the manufacturing of stealth aircraft. Stealth technology (ST) uses a combination of RAMs and geometry to minimize the reflection of electromagnetic waves back to a radar system. In this review article, working principle and basic constituents of ST are examined along with RAMs types in the light of composites. Moreover, recently developed carbonaceous-based polymer composites are critically discussed in terms of RAMs for stealth applications. A carbonaceous-based composite provides a high flexibility for the design and properties control. Carbon black particles, carbon fibers, carbon nanotubes (CNTs), and graphene are used in composites to tailor the wave's absorption properties of a composite. Multilayered structures are also recommended by researchers to extend the absorption band for better stealth application. Optimized absorption properties were achieved from composites containing carbon fiber as filler. Also, CNTs are preferred due to its smaller loading (0.35%) to get conductivity equal to higher concentration of carbon black (20%), which consequently improves the ST. Enhanced electromagnetic absorption properties can be achieved form the graphene-based RAMs along with incorporating the magnetic particles of different microstructures, particle size, and electromagnetic characteristics. This review will intensively cover the methodology of ST and different composites including carbon-based composites as RAMs for the use in stealth technology.