scholarly journals Refractory Brewster metasurfaces control the frequency and angular spectrum of light absorption

2019 ◽  
Vol 9 ◽  
pp. 184798041882481 ◽  
Author(s):  
Hoyeong Kwon ◽  
Hamidreza Chalabi ◽  
Andrea Alù

Ways to achieve highly efficient electromagnetic absorption over a broad bandwidth and broad angular spectrum have been discussed extensively in the past decades for various applications, such as low reflection devices and energy harvesting. To satisfy the efficiency requirements, metamaterial approaches have been explored in recent years. In this context, most studies have suggested the use of frequency selective surfaces or arrays of plasmonic resonators, which limit bandwidth and angular spectrum of performance. Here, we explore the application of refractory Brewster metasurfaces for photovoltaic applications. By matching the surface impedance of metasurfaces and free space at the Brewster angle, we show that metasurfaces can lead to efficient light absorption, and their response can be controlled accurately both in the angular and in the frequency spectrum to match the requirements of energy harvesting systems and facilitate large efficiency, high-temperature energy harvesting.

Electronics ◽  
2020 ◽  
Vol 9 (9) ◽  
pp. 1345 ◽  
Author(s):  
Mahmuda Khatun Mishu ◽  
Md. Rokonuzzaman ◽  
Jagadeesh Pasupuleti ◽  
Mohammad Shakeri ◽  
Kazi Sajedur Rahman ◽  
...  

In the past few years, the internet of things (IoT) has garnered a lot of attention owing to its significant deployment for fulfilling the global demand. It has been seen that power-efficient devices such as sensors and IoT play a significant role in our regular lives. However, the popularity of IoT sensors and low-power electronic devices is limited due to the lower lifetime of various energy resources which are needed for powering the sensors over time. For overcoming this issue, it is important to design and develop better, high-performing, and effective energy harvesting systems. In this article, different types of ambient energy harvesting systems which can power IoT-enabled sensors, as well as wireless sensor networks (WSNs), are reviewed. Various energy harvesting models which can increase the sustainability of the energy supply required for IoT devices are also discussed. Furthermore, the challenges which need to be overcome to make IoT-enabled sensors more durable, reliable, energy-efficient, and economical are identified.


Author(s):  
J. L. Farrant ◽  
J. D. McLean

For electron microscope techniques such as ferritin-labeled antibody staining it would be advantageous to have available a simple means of thin sectioning biological material without subjecting it to lipid solvents, impregnation with plastic monomers and their subsequent polymerization. With this aim in view we have re-examined the use of protein as an embedding medium. Gelatin which has been used in the past is not very satisfactory both because of its fibrous nature and the high temperature necessary to keep its solutions fluid. We have found that globular proteins such as the serum and egg albumins can be cross-linked so as to yield blocks which are suitable for ultrathin sectioning.


2020 ◽  
Vol 64 (1-4) ◽  
pp. 439-446
Author(s):  
Gildas Diguet ◽  
Gael Sebald ◽  
Masami Nakano ◽  
Mickaël Lallart ◽  
Jean-Yves Cavaillé

Magneto Rheological Elastomers (MREs) are composite materials based on an elastomer filled by magnetic particles. Anisotropic MRE can be easily manufactured by curing the material under homogeneous magnetic field which creates column of particles. The magnetic and elastic properties are actually coupled making these MREs suitable for energy conversion. From these remarkable properties, an energy harvesting device is considered through the application of a DC bias magnetic induction on two MREs as a metal piece is applying an AC shear strain on them. Such strain therefore changes the permeabilities of the elastomers, hence generating an AC magnetic induction which can be converted into AC electrical signal with the help of a coil. The device is simulated with a Finite Element Method software to examine the effect of the MRE parameters, the DC bias magnetic induction and applied shear strain (amplitude and frequency) on the resulting electrical signal.


Author(s):  
Wanchun Xiang ◽  
Shengzhong Liu ◽  
Wolfgang Tress

Inorganic perovskite based solar cells (PSCs) have been receiving unprecedented attention worldwide in the past several years due to their higher intrinsic stability towards high temperature and high theoretical power...


Author(s):  
Virgilio J Caetano ◽  
Marcelo A Savi

Energy harvesting from ambient vibration through piezoelectric devices has received a lot of attention in recent years from both academia and industry. One of the main challenges is to develop devices capable of adapting to diverse sources of environmental excitation, being able to efficiently operate over a broadband frequency spectrum. This work proposes a novel multimodal design of a piezoelectric energy harvesting system to harness energy from a wideband ambient vibration source. Circular-shaped and pizza-shaped designs are employed as candidates for the device, comparing their performance with classical beam-shaped devices. Finite element analysis is employed to model system dynamics using ANSYS Workbench. An optimization procedure is applied to the system aiming to seek a configuration that can extract energy from a broader frequency spectrum and maximize its output power. A comparative analysis with conventional energy harvesting systems is performed. Numerical simulations are carried out to investigate the harvester performances under harmonic and random excitations. Results show that the proposed multimodal harvester has potential to harness energy from broadband ambient vibration sources presenting performance advantages in comparison to conventional single-mode energy harvesters.


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