Fibre-Reinforced Polymer Reinforced Concrete Members under Elevated Temperatures: A Review on Structural Performance.

Several experimental and numerical studies have been conducted to address the structural performance of FRP-reinforced/strengthened concrete structures under and after exposure to elevated temperatures. The present paper reviews over 100 research studies focused on the structural responses of different FRP-reinforced/strengthened concrete structures after exposure to elevated temperatures, ranging from ambient temperatures to flame. Different structural systems were considered, including FRP laminate bonded to concrete, FRP-reinforced concrete, FRP-wrapped concrete, and concrete-filled FRP tubes. According to the reported data, it is generally accepted that, in the case of insignificant resin in the post curing process, as the temperature increases, the ultimate strength, bond strength, and structure stiffness reduce, especially when the glass transition temperature Tg of the resin is approached and exceeded. However, in the case of post curing, resin appears to preserve its mechanical properties at high temperatures, which results in the appropriate structural performance of FRP-reinforced/strengthened members at high temperatures that are below the resin decomposition temperature Td. Given the research gaps, recommendations for future studies have been presented. The discussions, findings, and comparisons presented in this review paper will help designers and researchers to better understand the performance of concrete structures that are reinforced/strengthened with FRPs under elevated temperatures and consider appropriate approaches when designing such structures.

Effect of Organoclay Addition on Rheological, Thermal, and Mechanical Properties of Nitrile Rubber/Phenolic Resin Blend.

In this study, the effects of NBR polarity and organoclay addition on the curing, rheological, mechanical, and thermal properties of an NBR/phenolic resin blend were investigated. The samples were prepared using a two-roll mill. The results showed that rheological and tensile properties improved due to the good distribution of nanoparticles, as well as the good compatibility of nitrile butadiene rubber with phenolic resin. The addition of 1.5 phr of nanoparticles to blends containing 33% and 45% acrylonitrile increased the curing torque difference by approximately 12% and 28%, respectively. In addition, the scorch time and curing time decreased in nanocomposites. Adding nanoparticles also increased the viscosity. The addition of phenolic resins and nanoparticles has a similar trend in modulus changes, and both of these factors increase the stiffness and, consequently, the elastic and viscous modulus of the specimens. Adding 1.5 phr of organoclay increased the tensile strength of the blends by around 8% and 13% in the samples with low and high content of acrylonitrile, respectively. Increasing the temperature of the tensile test led to a reduction in the tensile properties of the samples. Tensile strength, elongation at break, modulus, and hardness of the samples increased with increasing organoclay content. In addition, with increasing nanoparticle concentration, the samples underwent lower deterioration in tensile strength and Young's modulus at different temperatures compared to the blends. In the samples containing 1.5 phr of organoclay, the thermal decomposition temperatures were enhanced by around 24 and 27 °C for low and high acrylonitrile content.

Advancements in Fabrication and Application of Chitosan Composites in Implants and Dentistry: A Review.

Chitosan is a biopolymer that is found in nature and is produced from chitin deacetylation. Chitosan has been studied thoroughly for multiple applications with an interdisciplinary approach. Antifungal antibacterial activities, mucoadhesion, non-toxicity, biodegradability, and biocompatibility are some of the unique characteristics of chitosan-based biomaterials. Moreover, chitosan is the only widely-used natural polysaccharide, and it is possible to chemically modify it for different applications and functions. In various fields, chitosan composite and compound manufacturing has acquired much interest in developing several promising products. Chitosan and its derivatives have gained attention universally in biomedical and pharmaceutical industries as a result of their desired characteristics. In the present mini-review, novel methods for preparing chitosan-containing materials for dental and implant engineering applications along with challenges and future perspectives are discussed.

Biosensors and nanotechnology for cancer diagnosis (lung and bronchus, breast, prostate, and colon): a systematic review.

The second cause of death in the world has been reported to be cancer, and it has been on the rise in recent years. As a result of the difficulties of cancer detection and its treatment, the survival rate of patients is unclear. The early detection of cancer is an important issue for its therapy. Cancer detection based on biomarkers may effectively enhance the early detection and subsequent treatment. Nanomaterial-based nanobiosensors for cancer biomarkers are excellent tools for the molecular detection and diagnosis of disease. This review reports the latest advancement and attainment in applying nanoparticles to the detection of cancer biomarkers. In this paper, the recent advances in the application of common nanomaterials like graphene, carbon nanotubes, Au, Ag, Pt, and Fe3O4together with newly emerged nanoparticles such as quantum dots, upconversion nanoparticles, inorganics (ZnO, MoS2), and metal-organic frameworks for the diagnosis of biomarkers related to lung, prostate, breast, and colon cancer are highlighted. Finally, the challenges, outlook, and closing remarks are given.