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Plasmonic Materials and Their Applications
Published in Song Sun, Wei Tan, Su-Huai Wei, Emergent Micro- and Nanomaterials for Optical, Infrared, and Terahertz Applications, 2023
Jinfeng Zhu, Yinong Xie, Yuan Gao
At high frequency, surface plasmons can strongly confine electromagnetic fields on a length scale much smaller than the wavelength. At lower frequencies (such as microwave or THz frequencies), such field confinement is broken as the electromagnetic field can only penetrate a tiny depth into the metallic material due to its large permittivity that can be approximated as a perfect electric conductor. Since the inducible field amplitude inside the metallic material is essential to provide a non-zero component of the electric field parallel to the surface, which is necessary to establish an oscillatory space-charge distribution, the SPP vanishes for an ideal electrical conductor. Consequently, as the frequency decreases, the SPP gradually evolves into a grazing-incidence light field rather than the plasmon mode.
Promise of Self-lubricating Aluminum-Based Composite Material
Published in Chander Prakash, Sunpreet Singh, J. Paulo Davim, Functional and Smart Materials, 2020
Neeraj Kumar Bhoi, Harpreet Singh, Saurabh Pratap
In order to maintain material properties to be stable, materials are subjected to different functional environment from largest to nano length scale. The process followed for the stable phase development over the substrate material always been a challenging task by the consideration of fundamental material configuration and chemical composition imposed upon the surface. The presence of oxides, carbides and several inter-metallic compounds on the surface largely enhances the hardness, fracture toughness and wear resistance of the material [1]. The enthusiasm to play with the surface texture of the material by the additions of different layers over the surface material always had been a quest for the research community. Crafting for the improved performance in surface chemistry is a key concern in the mechanical and tribological industry. High wear and corrosion-resistant materials draw larger interest in the various sectors such as automobile, aerospace, naval and spacecraft industries [2]. Surface modification is a major breakthrough in the numerous industrial civilizations with higher productivity and improved functional performance [3]. However, the requirement for higher specific energy, larger processing time and numerous process variables needs to be controlled for better functional application. Composite material tailors and combines the best properties of the matrix and supports element by providing (i) ductility and toughness of the matrix and (ii) strength and modulus of the reinforcement element for different structural and functional applications [4,5].
Introduction to Microscale Heat Transfer
Published in C. B. Sobhan, G. P. Peterson, Microscale and Nanoscale Heat Transfer, 2008
Radiation-length-scale effects occur when the characteristic length scales of surfaces or structures undergoing radiative exchange are of the same order of magnitude as the wavelength. Microscale radiative transfer has become increasingly significant, as micromachining technology has become capable of producing many structures and solid films with these characteristic dimensions. As in the case of microscale conduction, theoretical and experimental approaches have been utilized to study microscale radiative behavior, as well as to use electromagnetic radiation for making measurements in the microscale. These have involved investigations of phenomena such as emissions from microscale structures and the measurement of emissivity; studies on scattering, reflection, absorption, and transmission in thin films and structures; and the estimation of the related radiation properties. The use of many of these phenomena for the measurement of local temperatures and radiative fluxes in thin films and microscale structures and devices has also gained importance.
Buckling analysis of restrained nanobeams using strain gradient elasticity
Published in Waves in Random and Complex Media, 2022
Mustafa Özgur Yaylı, Busra Uzun, Babür Deliktaş
Classical continuum theories are not sufficient to explain the mechanical behaviors of nano/micro-scale structures because of their length scale-free constitutive equations. In the nano/micro-scale structures, the lengths are in the order of inter-atomic distances, so the nonlocal and small-length scale effects can be significant. Hence, classical continuum mechanics need to be modified by introducing length scale to their constitutive equations so that resulting nonlocal constitutive relations provide a relatively simple and less time-consuming without compromising the accuracy of the results in predicting the mechanical behavior of nano/micro-scale structures. Therefore, length-dependent continuum theories have received more attention in modeling of nano-scale structures and devices.
Free vibration and instability analysis of a viscoelastic micro-shell conveying viscous fluid based on modified couple stress theory in thermal environment
Published in Mechanics Based Design of Structures and Machines, 2022
Kaveh Rashvand, Akbar Alibeigloo, Mehran Safarpour
Experimental and analytical observations reveal that the behaviors of micro-scale structures are depended on the length scale of their material (Rashvand et al. 2012, 2013; Rashvand, Rezazadeh, and Madinei 2014; Hashemi and Asghari 2017; Bagheri and Asghari 2019; Karamanli and Aydogdu 2019). Therefore, the classical theories (CTs) are not capable to predict their behaviors in microscale properly and an alternative approach should be made to non-classical theories. The micropolar theory (Cosserat and Cosserat 1909), the couple stress theory (Mindlin 1963), the strain gradient theory (Mindlin 1965), nonlocal theory (Eringen 1972) and surface stress theory (Gurtin and Murdoch 1975) are examples of non-classical theories that are presented to accurately predict the mechanical behavior of micro-structures. According to the couple stress theory, there is a torque per unit area, or couple stress, as well as the usual force per unit area, or stress in classical theories. Yang et al. 2002 modified the couple stress theory (e.g., Mindlin (1965)) based on an additional equilibrium relation to predicting the behavior of the couples.
Elastoplastic mean-field homogenization: recent advances review
Published in Mechanics of Advanced Materials and Structures, 2022
Zoubida Sekkate, Ahmed Aboutajeddine, Abbass Seddouki
Accordingly, the trial and error practice based on the selection approach is evolving to a more streamlined and systematic one, through a composite material design process. In this design perspective, the desired material properties and performance at each length scale depend on the observable microstructure at the corresponding length. The massive differences in these length scales present many difficulties to generate a finite element (FE) mesh that accurately represents the microstructure and achieves a numerical solution on the macroscopic scale within a reasonable time interval [1]. Besides, the finite element procedure bears a geometric restriction for composites reinforced with high aspect ratios and large volume fraction of particles [2]. To overcome these restrictive hurdles, micromechanical models turn out to be very useful. They rely on the derivation of the macroscopic behavior of new materials while taking into account the microstructural parameters of each phase, without the need for trial and error experimentations and for a lower computing time than that of direct bridging methods (FE).