Generation of fractional acoustic vortex with a discrete Archimedean spiral structure plate

2018 ◽  
Vol 112 (17) ◽  
pp. 173501 ◽  
Author(s):  
Yu-Rou Jia ◽  
Qi Wei ◽  
Da-Jian Wu ◽  
Zheng Xu ◽  
Xiao-Jun Liu
Keyword(s):  
Spiral Structure ◽  
Archimedean Spiral ◽  
Structure Plate

Orthogonal spiral structures for energy harvesting applications: Theoretical and experimental analysis

2018 ◽  
Vol 29 (9) ◽  
pp. 1900-1912 ◽  
Author(s):  
Auteliano Antunes Dos Santos ◽  
Jared D. Hobeck ◽  
Daniel J Inman
Keyword(s):  
Energy Harvesting ◽  
Cantilever Beam ◽  
Microelectromechanical Systems ◽  
Spiral Structure ◽  
Structure Design ◽  
Lumped Parameter Model ◽  
Archimedean Spiral ◽  
Reduced Frequency ◽  
Harvesting Systems ◽  
Spiral Structures

The capture of energy from vibration of mechanical systems has been extensively studied with the goal of providing power for various microelectromechanical systems. The traditional cantilever beam approach was used as a starting design for more complex, multiple-beam structures like zigzag or spiral geometries. This work presents the orthogonal spiral structure, an alternative compact periodic structure for reduced frequency energy harvesting. The proposed orthogonal spiral structure design is inspired by a combination of zigzag and Archimedean spiral geometries. The orthogonal spiral structure takes advantage of a simple cantilever beam-based design as with the zigzag, but includes the compact concentric-type design of an Archimedean spiral. First, the fundamental frequency is estimated using a lumped parameter model for the substrate beam and the results are compared with experimental results for two different sizes of orthogonal spiral structures. Then, the same model is updated to include a layer of piezoelectric material and used to identify the strain nodes along each beam obtained from the first mode shape. Finally, electromechanical modeling is developed allowing for the evaluation of the energy harvested from base excitations. The results show that the orthogonal spiral structure can be used as an alternative to current energy harvesting systems for micro scale applications.

scholarly journals Interaction of an Archimedean spiral structure with orbital angular momentum light

2018 ◽  
Vol 20 (9) ◽  
pp. 095005 ◽  
Author(s):  
R M Kerber ◽  
J M Fitzgerald ◽  
X Xiao ◽  
S S Oh ◽  
S A Maier ◽  
...  
Keyword(s):  
Angular Momentum ◽  
Orbital Angular Momentum ◽  
Spiral Structure ◽  
Archimedean Spiral

Anomalous diffusion on Archimedean spiral structure with Cattaneo flux model

2020 ◽  
Vol 319 ◽  
pp. 114256
Author(s):  
Kheder Suleiman ◽  
Chunyan Liu ◽  
Xuelan Zhang ◽  
Erhui Wang ◽  
Lianxi Ma ◽  
...  
Keyword(s):  
Anomalous Diffusion ◽  
Spiral Structure ◽  
Archimedean Spiral ◽  
Flux Model

Density waves in disk galaxies

1967 ◽  
Vol 31 ◽  
pp. 313-317 ◽  
Author(s):  
C. C. Lin ◽  
F. H. Shu
Keyword(s):  
Mathematical Analysis ◽  
Spiral Structure ◽  
Stellar System ◽  
Collective Modes ◽  
Disk Galaxies ◽  
Spiral Pattern ◽  
Density Waves ◽  
The Galaxy ◽  
Detailed Mathematical Analysis

Density waves in the nature of those proposed by B. Lindblad are described by detailed mathematical analysis of collective modes in a disk-like stellar system. The treatment is centered around a hypothesis of quasi-stationary spiral structure. We examine (a) the mechanism for the maintenance of this spiral pattern, and (b) its consequences on the observable features of the galaxy.

Mixed focused-acoustic-vortices generated by an artificial structure plate engraved with discrete rectangular holes

2021 ◽  
Vol 118 (4) ◽  
pp. 043503
Author(s):  
Xin-Rui Li ◽  
Yu-Rou Jia ◽  
Yan-Chun Luo ◽  
Jie Yao ◽  
Da-Jian Wu
Keyword(s):  
Artificial Structure ◽  
Structure Plate

Magnetic Field Spectroheliograms from the San Fernando Observatory

1971 ◽  
Vol 43 ◽  
pp. 329-339 ◽  
Author(s):  
Dale Vrabec
Keyword(s):  
Magnetic Field ◽  
Magnetic Fields ◽  
Spiral Structure ◽  
Longitudinal Component ◽  
Solar Telescope ◽  
Solar Magnetic Fields ◽  
San Fernando ◽  
Field Lines ◽  
The Magnetic Field ◽  
Field Network

Zeeman spectroheliograms of photospheric magnetic fields (longitudinal component) in the CaI 6102.7 Å line are being obtained with the new 61-cm vacuum solar telescope and spectroheliograph, using the Leighton technique. The structure of the magnetic field network appears identical to the bright photospheric network visible in the cores of many Fraunhofer lines and in CN spectroheliograms, with the exception that polarities are distinguished. This supports the evolving concept that solar magnetic fields outside of sunspots exist in small concentrations of essentially vertically oriented field, roughly clumped to form a network imbedded in the otherwise field-free photosphere. A timelapse spectroheliogram movie sequence spanning 6 hr revealed changes in the magnetic fields, including a systematic outward streaming of small magnetic knots of both polarities within annular areas surrounding several sunspots. The photospheric magnetic fields and a series of filtergrams taken at various wavelengths in the Hα profile starting in the far wing are intercompared in an effort to demonstrate that the dark strands of arch filament systems (AFS) and fibrils map magnetic field lines in the chromosphere. An example of an active region in which the magnetic fields assume a distinct spiral structure is presented.

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