CNT-Based Nano Medicine From Synthesis to Therapeutic Application

Carbon nanotubes (CNTs) are allotropes of carbon consisting of cylindrical tubes, made up of graphite with a diameter of several nm to a length of several mm. They had extraordinary structural, mechanical, and electronic properties due to their small size and mass, high mechanical resilience, and high electrical and thermal conductivity. Their large surface area made them applicable in pharmacy and medicine and adsorb or conjugate a broad variety of medical and diagnostic agents (drugs, genes, vaccines, antibodies, biosensors, etc.). They are often used to deliver drugs directly into the cells without going through the metabolic process of body. In addition to drug delivery and gene therapy, CNTs are also used for tissue regeneration, diagnostic biosensors, chiral drug enantiomer separation, drug extraction, and drug or pollutant analysis. CNTs have recently been discovered as effective antioxidants. The ADME and toxicity of different types of CNTs have also been documented here, as well as the prospects, advantages, and challenges of this promising bio-nano technology.

Mechanical performance of carbon-fibre braided composite tubes in tension and compression

This article examines the effect of braid angle on the mechanical performance of carbon-epoxy braided tubes in tension and compression. Vacuum-assisted resin transfer moulding is used to produce a variety of tubes with several combinations of 15◦and 20◦ braid angles. As uniaxial tensile testing of cylindrical tubes is not trivial, two tensile testing fixture designs are explored. It is found that a combination of mechanical and adhesive gripping produces repeatable fractures between the grips, with no slipping. Tubes with lower braid angles exhibit higher strengths both in tension and compression, as well as absorbing greater amounts of energy in compression.

Crashworthiness analysis of cylindrical tubes with coupling effects under quasi-static axial loading: An experimental and numerical study

In most cylindrical tubes, the occurrence of negative stiffness under compression is unavoidable. This downward trend in the force–displacement relationship means a decrease in the energy-absorption capacity. To this end, this paper introduces a new assembly method comprising two concentric cylindrical tubes. The inner cylinder possesses positive Poisson's ratio behavior, whereas the outer cylinder exhibits negative Poisson's ratio behavior. When compressed, the outer and inner cylinders shrink and expand, respectively, creating surface contacts between the two cylinders, called coupling effects. This property not only avoids the occurrence of negative stiffness in outer cylindrical tube, but also increases the energy-absorption capacity in an upward trend in the force–displacement relationship. To confirm this claim, three different types of cylindrical tubes, possessing positive Poisson’s ratio, zero Poisson's ratio, and negative Poisson’s ratio behaviors, are considered. A finite-element analysis is implemented to simulate deformation patterns of cylindrical tubes. Then, to verify the results of finite-element analysis, a laser-cutting method is applied to fabricate cylindrical tubes from stainless steel tubes. The results show that the proposed assembly method increases the energy-absorption capacity by up to 95% compared to the well-known auxetic tube. Next, a parametric study is performed, in which the gap space between the two cylinders is considered as a design variable. The results reveal the smaller the gap space, the higher the energy-absorption capacity. The absorbed energy in the assembled cylinders without gap space is 17.6 J, which is 36% greater than that of cylinders with 13 mm gap space. The effects of relative density and crushing speed are also evaluated. When compared to the crushing speed, the energy-absorption capacity is highly dependent on relative density.

Numerical Treatment for the Second Law Analysis in Hydromagnetic Peristaltic Nanomaterial Rheology: Endoscopy Applications

In current study, analysis is presented for peristaltic motion of applied magnetic field and entropy generation within couple stress (Cu/H2O) nanofluid through an endoscope. An endoscope contains two coaxial cylindrical tubes in which the internal tube is nonflexible while the external tube has sinusoidal wave passing through the boundary. Influences of mixed convection along with applied magnetic field are encountered as well. Formulated governing model is fabricated introducing long wavelength and creeping Stokesian flow approximation which are then analyzed numerically by utilizing Adams Bashforth method. For a physical insight, results are demonstrated to examine the behaviors of flow profiles and entropy generation number for emerging flow parameters with the help of graphs, bar-charts and tables.