Search Results (4)

The carbon nanotube (CNT) is celebrated for its electrothermal property, which indicates the capability of a material to transform electrical energy into heat due to the Joule effect. The CNT nanostructure itself, as a one-dimensional material, limits the electron conduction path, thereby creating a unique heating phenomenon. In this work, we explore the possible correlation between CNT alignment in sheets and heating performance. The alignment of carbon nanotubes is induced by immersion and stretching in chlorosulfonic acid (CSA) solution. The developed CSA-stretched CNT sheet demonstrated excellent heating performance with a fast response rate of 6.5 °C/s and reached 180 °C in less than 30 s under a low voltage of 2.5 V. The heating profile of the stretched CNT sheet remained stable after bending and twisting movements, making it a suitable heating material for wearable devices, heatable smart windows, and in de-icing or defogging applications. The specific strength and specific conductance of the CSA-stretched CNT sheet also increased five- and two-fold, respectively, in comparison to the pristine CNT sheet. Full article

The purpose of this article is to provide an overview of the growth, maturation and resistance training-related changes in muscle-tendon and neuromuscular mechanisms in youth, and the subsequent effect on performance. Sprinting, jumping, kicking, and throwing are common movements in sport that have been shown to develop naturally with age, with improvements in performance being attributed to growth and maturity-related changes in neuromuscular mechanisms. These changes include moderate to very large increases in muscle physiological cross-sectional area (CSA), muscle volume and thickness, tendon CSA and stiffness, fascicle length, muscle activation, pre-activation, stretch reflex control accompanied by large reductions in electro-mechanical delay and co-contraction. Furthermore, a limited number of training studies examining neuromuscular changes following four to 20 weeks of resistance training have reported trivial to moderate differences in tendon stiffness, muscle CSA, muscle thickness, and motor unit activation accompanied by reductions in electromechanical delay (EMD) in pre-pubertal children. However, the interaction of maturity- and training-related neuromuscular adaptions remains unclear. An understanding of how different neuromuscular mechanisms adapt in response to growth, maturation and training is important in order to optimise training responsiveness in youth populations. Additionally, the impact that these muscle-tendon and neuromuscular changes have on force producing capabilities underpinning performance is unclear. Full article

This article investigates unsteady magnetohydrodynamic (MHD) mixed convective and thermally radiative Jeffrey nanofluid flow in view of a vertical stretchable cylinder with radiation absorption and heat; the reservoir was addressed. The mathematical formulation of Jeffrey nanofluid is established based on the theory of boundary layer approximations pioneered by Prandtl. The governing model expressions in partial differential equations (PDEs) form was transformed into dimensionless form via similarity transformation technique. The set of nonlinear nondimensional partial differential equations are solved with the help of the homotopic analysis method. For the purpose of accuracy, the optimizing system parameters, convergence, and stability analysis of the analytical algorithm (CSA) were performed graphically. The velocity, temperature, and concentration flow are studied and shown graphically with the effect of system parameters such as Grashof number, Hartman number, Prandtl number, thermal radiation, Schmidt number, Eckert number, Deborah number, Brownian parameter, heat source parameter, thermophoresis parameter, and stretching parameter. Moreover, the consequence of system parameters on skin friction coefficient, Nusselt number, and Sherwood number is also examined graphically and discussed. Full article

Chronic thromboembolic pulmonary hypertension (CTEPH) results from an obstruction of pulmonary arteries (PAs) by organized thrombi. The stenosed PAs are targeted during balloon pulmonary angioplasty (BPA). We aimed to evaluate the mechanism of BPA in inoperable patients with CTEPH. We analyzed stenosed PAs with intravascular grey-scale ultrasound (IVUS) to determine the cross-sectional area (CSA) of arterial lumen and of organized thrombi. The composition of organized thrombi was assessed using virtual histology. We distinguished two mechanisms of BPA: Type A with dominant vessel stretching, and type B with dominant thrombus compression. PAs were assessed before (n = 159) and after (n = 98) BPA in 20 consecutive patients. Organized thrombi were composed of dark-green (57.1 (48.0–64.0)%), light-green (34.0 (21.4–46.4)%), red (6.4 (2.9–11.7)%;) and white (0.2 (0.0–0.9)%) components. The mechanism type depended on vessel diameter (OR = 1.09(1.01–1.17); p = 0.03). In type B mechanism, decrease in the amount of light-green component positively correlated with an increase in lumen area after BPA (r = 0.50; p = 0.001). The mechanism of BPA depends on the diameter of the vessel. Dilation of more proximal PAs depends mainly on stretching of the vessel wall while dilation of smaller PAs depends on compression of the organized thrombi. The composition of the organized thrombi contributes to the effect of BPA. Full article