Natural fibers are getting attention from researchers and academician to utilize in polymer composites due to their ecofriendly nature and sustainability. The aim of this review article is to provide a comprehensive review of the foremost appropriate as well as widely used natural fiber reinforced polymer composites (NFPCs) and their applications. In addition, it presents summary of various surface treatments applied to natural fibers and their effect on NFPCs properties. The properties of NFPCs vary with fiber type and fiber source as well as fiber structure. The effects of various chemical treatments on the mechanical and thermal properties of natural fibers reinforcements thermosetting and thermoplastics composites were studied. A number of drawbacks of NFPCs like higher water absorption, inferior fire resistance, and lower mechanical properties limited its applications. Impacts of chemical treatment on the water absorption, tribology, viscoelastic behavior, relaxation behavior, energy absorption flames retardancy, and biodegradability properties of NFPCs were also highlighted. The applications of NFPCs in automobile and construction industry and other applications are demonstrated. It concluded that chemical treatment of the natural fiber improved adhesion between the fiber surface and the polymer matrix which ultimately enhanced physicomechanical and thermochemical properties of the NFPCs.

This study examines the buckling behavior of sandwich cylindrical microshells made of functionally graded materials under uniform magneto-electric load. The analysis utilizes a high-order shear and normal deformation shell theory, incorporating a material length scale parameter from the couple stress theory. Hamilton's principle is used to derive the equations of motion and boundary conditions at both ends. The Navier procedure is employed to determine the dimensionless critical buckling load for three types of functionally graded sandwich cylindrical microshells, with a vector used to represent the uniform magneto-electric fields at both ends. Results indicate that angled functionally graded sandwich cylindrical microshells exhibit higher stiffness in couple stress theory than in normal FGS, resulting in an increased dimensionless critical buckling load. Moreover, the material length scale parameter has a significant impact on the dimensionless critical buckling load across various axial and circumferential wavenumbers. An increase in power-law index n for specific values of dimensionless length scale parameter (l/h) leads to a decrease in DCB load according to MCST.

In order to find a universal empirical relationship among the absolute efficiency of a photopeak, the energy of gamma ray and the distance from the source to the detector face, we used a modern gammaray spectroscopy called (SPECTECH UCS-20) with a scintillation detector, NaI(Tl), of dimensions 3.8cm(diameter)×2.5cm(thick). The system is connected to a personal computer with a program installed for this purpose. The absolute efficiency have been found using standard radioactive sources (Na-22, Mn-54, Co-60, Cd-109, Eu-152) in the energy range (88-1408) keV and a distance (1.25-10.25)cm. A fit to the figure of measured absolute efficiency with distance was applied, and we have found that the best fit is the power fit. Also we found the best equation to calculate the two constants, in the power fit equations .Thus we have combined the absolute efficiency, energy, and distance in one universal empirical equation. The experimental results have been compared with those calculated by the universal empirical equation and a good correspondence has been found between them .Further, we find detector efficiency of standard sample from (KCl) putted in touch to the detector surface, this efficiency can be used to calculate the concentration of (40 k) in different situations. ‫ﺍﻟﻭﻤﻴﻀﻲ‬ ‫ﺍﻟﻜﺎﺸﻑ‬ ‫ﻜﻔﺎﺀﺓ‬ ‫ﺒﻴﻥ‬ ‫ﺸﺎﻤﻠﺔ‬ ‫ﺘﺠﺭﻴﺒﻴﺔ‬ ‫ﻋﻼﻗﺔ‬ ‫ﺇﻴﺠﺎﺩ‬ NaI(Tl) ...