Thermal and mechanical properties of hemp fabric-reinforced nanoclay-cement nano-composites

The influence of nanoclay on thermal and mechanical properties of hemp fabric-reinforced cement composite is presented in this paper. Results indicate that these properties are improved as a result of nanoclay addition. An optimum replacement of ordinary Portland cement with 1 wt% nanoclay is observed through improved thermal stability, reduced porosity and water absorption as well as increased density, flexural strength, fracture toughness and impact strength of hemp fabric-reinforced nanocomposite. The microstructural analyses indicate that the nanoclay behaves not only as a filler to improve the microstructure but also as an activator to promote the pozzolanic reaction and thus improve the adhesion between hemp fabric and nanomatrix

Influence of halloysite nanotubes on physical and mechanical properties of cellulose fibres reinforced vinyl ester composites

Natural fibres are generally added to polymer matrix composites to produce materials with the desirable mechanical properties of higher specific strength and higher specific modulus while at the same time to maintain a low density and low cost. The physical and mechanical properties of polymer composites can be enhanced through the addition of nanofillers such as halloysite nanotubes. This article describes the fabrication of vinyl ester eco-composites and eco-nanocomposites and characterizes these samples in terms of water absorption, mechanical and thermal properties. Weight gain test and Fourier transform infrared analysis indicated that 5% halloysite nanotube addition gave favourable reduction in the water absorption and increased the fibre–matrix adhesion leading to improved strength properties in the eco-nanocomposites. However, halloysite nanotube addition resulted in reduced toughness but improved thermal stability

Fibre Distribution and the Process-Property Dilemma

The options for the fibre reinforcement of polymer matrix composites cover a range from short-fibre chopped strand mat, through woven fabric to unidirectional pre-impregnated (prepreg) reinforcements. The modelling of such materials may be simplified by assumptions such as perfect regular packing of fibres and the total absence of fibre waviness. However, these and other features such as the crimp or waviness in woven fabrics make real materials more complex than the simplified models. Clustering of fibres creates fibre-rich and resin-rich volumes (FRV and RRV respectively) in the composites. Prior to impregnation, large RRV will be pore-space that can expedite the flow of resin in liquid composite moulding processes (especially resin transfer moulding (RTM) and resin infusion under flexible tooling (RIFT). In the composite, the clustering of fibres tends to reduce the mechanical properties. The use of image processing and analysis can permit micro-/meso-structural characterisation which may correlate to the respective properties. This chapter considers the quantification of microstructure images in the context of the process-property dilemma for woven carbon-fibre reinforced composites with the aim of increasing understanding of the balance between processability and mechanical performance

Mechanical properties of cotton fabric reinforced geopolymer composites at 200-1000 °C

Geopolymer composites containing woven cotton fabric (0–8.3 wt%) were fabricated using the hand lay-up technique, and were exposed to elevated temperatures of 200 °C, 400 °C, 600 °C, 800 °C and 1000 °C. With an increase in temperature, the geopolymer composites exhibited a reduction in compressive strength, flexural strength and fracture toughness. When heated above 600 °C, the composites exhibited a significant reduction in mechanical properties. They also exhibited brittle behavior due to severe degradation of cotton fibres and the creation of additional porosity in the composites. Microstructural images verified the existence of voids and small channels in the composites due to fibre degradation

New Solutions for (1+1)-Dimensional and (2+1)-Dimensional Ito Equations

Using the extended F-expansion method based on computerized symbolic computation technique, we find several new solutions of (1+1)-dimensional and (2+1)-dimensional Ito equations. These solutions contain hyperbolic and triangular solutions. It is shown that the power of the extended F-expansion method is its ease of use to determine shock or solitary type of solutions. In addition, as an illustrative sample, the properties for the extended F-expansion solutions of the Ito equations are shown with some figures

The effect of CuO additive on the mechanical and radiation shielding features of Li2B4O7-Pb2O3glass system

The effect of substitution Pb2O3 by CuO content was studied for 75% Li2B4O7 + (25 - x)Pb2O3 + xCuO glass system where x = 0, 5, 10, 15, 20, and 25 wt%. The mechanical and radiation shielding properties were evaluated for the investigated glass samples. The mechanical properties included Young's, shear, bulk, longitudinal, Poisson ratio, and micro-hardness were computed theoretically based on the packing factor (Vi) and dissociation energy (Gi) of the metal oxides constituting the existing glass samples using the Makishima-Mackenzie model. The obtained results depicted the insertion of CuO enhances the different mechanical parameters up to 20 mol% of the investigated LBPCu glasses. Furthermore, the radiation shielding properties were studied for the investigated LBPCu glass using the Monte Carlo N-particle transport code (MCNP-5) simulation. MCNP-5 was used to detect the simulated linear attenuation coefficient (LAC) and then mass attenuation coefficient (MAC) and other factors based on various gamma-ray sources with energies of 0.24, 0.66, 1.17, 1.33, and 1.40 MeV. The results showed that LAC's highest value decreased from 0.578 to 0.320 cm-1 for glasses LBPCu0 and LBPCu25, respectively, at low energy of 0.284 MeV. Moreover, the effective and equivalent atomic numbers (Zeff and Zeq), buildup factor (EBF), and absorption buildup factor (EABF) were evaluated for the investigated LBPCu glass using the BXCOM program. The results revealed that the shielding properties of the investigated glasses improved by the insertion of CuO content. © 2020 SECV.Resumen Se estudió el efecto de la sustitución de Pb2O3por el contenido de CuO para el 75% de Li2B4O7+ (25 - x)Pb2O3+ xCuO sistema de vidrio donde x = 0, 5, 10, 15, 20 y 25% en peso. Se evaluaron las propiedades mecánicas y de protección contra la radiación para las muestras de vidrio investigadas. Las propiedades mecánicas incluidas Young, cizallamiento, volumen, longitudinal, relación de Poisson y microdureza se calcularon teóricamente en función del factor de empaquetamiento (Vi) y la energía de disociación (Gi) de los óxidos metálicos que constituyen las muestras de vidrio existentes utilizando el método Makishima-Mackenzie. modelo. Los resultados obtenidos muestran que la inserción de CuO mejora los diferentes parámetros mecánicos hasta en un 20% mol de los vidrios LBPCu investigados. Además, se estudiaron las propiedades de protección contra la radiación para el vidrio LBPCu investigado utilizando la simulación del código de transporte de partículas N de Monte Carlo (MCNP-5). Se utilizó MCNP-5 para detectar el coeficiente de atenuación lineal simulado (LAC) y luego el coeficiente de atenuación de masa (MAC) y otros factores basados en varias fuentes de rayos gamma con energías de 0,24, 0,66, 1,17, 1,33 y 1,40 MeV. Los resultados mostraron que el valor más alto de LAC disminuyó de 0,578 a 0,320 cm-1para los vasos LBPCu0 y LBPCu25, respectivamente, a baja energía de 0,284 MeV. Además, se evaluaron los números atómicos efectivos y equivalentes (Zeffy Zeq), el factor de acumulación (EBF) y el factor de acumulación de absorción (EABF) para el vidrio LBPCu investigado utilizando el programa BXCOM. Los resultados revelaron que las propiedades de protección de los vidrios investigados mejoraron mediante la inserción de contenido de CuO. © 2022 Sociedad Espanola de Ceramica y Vidrio. All rights reserved.Taif University, TU: TURSP-2020/226We would like to thank Taif University Researchers Supporting Project number (TURSP-2020/226), Taif University, Taif, Saudi Arabia for financial support