Assessment of Absorbed Power Density (Sab) at the Surface of Flat Lossy Medium in GHz Frequency Range : A case of Hertz dipole

2020 ◽  
Author(s):  
Dragan Poljak ◽  
Mario Cvetkovic
Keyword(s):  
Power Density ◽  
Frequency Range ◽  
Lossy Medium ◽  
Absorbed Power

scholarly journals Structural Phase States and Surface Properties of Steel 45 after Electroexplosive Borocoppering and Electron-Beam Treatment

2021 ◽  
pp. 17-23
Author(s):  
E.S. Vashchuk ◽  
E.A. Budovskikh ◽  
L.P. Bashchenko ◽  
V.E. Gromov ◽  
K.V. Aksenova
Keyword(s):  
Wear Resistance ◽  
Electron Beam ◽  
Power Density ◽  
Structural Phase ◽  
Combined Treatment ◽  
Grain Structure ◽  
Electron Beam Treatment ◽  
Boron Powder ◽  
Near Surface ◽  
Absorbed Power

The paper concerns improving the microhardness and wear resistance of steel 45 by the combined treatment of electroexplosive borocoppering with the subsequent electron-beam treatment. It is found that surface roughness at the area of the electroexplosive treatment increases along with the absorbed power density and the mass of boron powder. The electron-beam treatment leads to a decrease of roughness and appearance of craters instead of radial melt flow traces. The depth structure of the electroexplosive alloying area with a thickness of 25 µm includes a coating layer, near-surface, intermediate, and boundary layers. The surface microhardness and the depth of the hardening zone after the electroexlosive alloying increase along with the absorbed power density and boron concentration and reach the values of 1400 HV The electron-beam treatment causes merging of the coating and the surface layers and increases the hardening zone depth up to 80 µm. A cellular or dendritic crystallization structure is formed near the surface, and a grain structure is formed in the depth. The inhomogeneous distribution of alloying elements over the volume of the alloying area and its adjustment during the electron-beam treatment are established. The inter-dendritic distances and grain diameters increase as the absorbed power density becomes higher with the increase of the electron-beam treatment exposure time. Also, the size of martensite needles increases in the depth. The combined treatment produces the sub microcrystalline strengthening phases-borides FeB, Fe2B, FeB2, carboboride Fe23 (C, B)6 , and carbide B4C. The microhardness level is reduced to 800 HV, and the wear resistance increases up to five times when compared to the wear resistance of the base.

Performance of lead-free piezoelectric materials in cantilever-based energy harvesting devices

2014 ◽  
Vol 03 (02) ◽  
pp. 1450010 ◽  
Author(s):  
Anuruddh Kumar ◽  
Rajeev Kumar ◽  
Vishal S. Chauhan ◽  
Rahul Vaish
Keyword(s):  
Energy Harvesting ◽  
Power Density ◽  
Lead Zirconate Titanate ◽  
Piezoelectric Materials ◽  
Lead Zirconate ◽  
Lead Free ◽  
Frequency Range ◽  
Mean Power ◽  
Piezoelectric Energy ◽  
Energy Harvesting Devices

Energy harvesting is one of the emerging applications of piezoelectric materials. In order to replace conventional lead-based materials with lead-free materials, it is important to evaluate their performance for such applications. In the present study, finite element method-based simulation shows mean power density produced from ( K 0.475 Na 0.475 Li 0.05)( Nb 0.92 Ta 0.05 Sb 0.03) O 3 add with 0.4 wt.% CeO 2 and 0.4 wt.% MnO 2 (KNLNTS) bimorph is 96.64% of lead zirconate titanate ( Pb [ Zr x Ti 1-x] O 3) (PZT) ceramics. Load resistance (R), length of proof mass (Lm) and thickness of host layer (th) are optimized (using genetic algorithm) for maximum power density and tuning the operating frequency range which is near to natural frequency of the structure. The lead-free piezoelectric material KNLNTS has comparable results to that of PZT for piezoelectric energy harvester in the ambient frequency range of 90 Hz to 110 Hz. Results show that KNLNTS ceramics can be potentially used in energy harvesting devices.

scholarly journals A Dual Resonance Electromagnetic Vibration Energy Harvester for Wide Harvested Frequency Range with Enhanced Output Power

Energies ◽  
2021 ◽  
Vol 14 (22) ◽  
pp. 7675
Author(s):  
Zhijie Feng ◽  
Han Peng ◽  
Yong Chen
Keyword(s):  
Resonant Frequency ◽  
Power Density ◽  
Output Power ◽  
Energy Harvester ◽  
Relative Displacement ◽  
Wide Frequency Range ◽  
Frequency Range ◽  
Vibration Energy Harvester ◽  
Resonance Frequencies ◽  
Dual Resonance

A dual resonance vibration electromagnetic energy harvester (EMEH) is proposed in this paper to extend frequency range. Compared with the conventional dual resonance harvester, the proposed system realizes an enhanced “band-pass” harvesting characteristic by increasing the relative displacement between magnet and coil among two resonance frequencies with a significant improvement in the average harvested power. Furthermore, two resonant frequencies are decoupled in the proposed system, which leads to a more straightforward design. The proposed dual resonance EMEH is constructed with a tubular dual spring-mass structure. It is designed with a serpentine planar spring and the coil position is optimized for higher power density with an overall size of 53.9 cm3 for the dual resonance EMEH. It realizes an output power of 11 mW at the first resonant frequency of 58 Hz, 14.9 mW at the second resonant frequency of 74.5 Hz, and 0.52 mW at 65 Hz, which is in the middle of the two resonance frequencies. The frequency range of output power above 0.5 mW is from 55.8 Hz to 79.1 Hz. The maximum normalized power density (NPD) reaches up to 2.77 mW/(cm3·g2). Compared with a single resonance harvester design under the same topology and outer dimension at a resonant frequency of 74.5 Hz, the frequency range in the proposed EMEH achieves more than a 2× times extension. The proposed dual resonance EMEH also has more than 2 times wider frequency range than other state-of-art wideband EMEHs. Therefore, the proposed dual resonance EMEH is demonstrated in this paper for a high maximum NPD and higher NPD over a wide frequency range.

Piezoelectric energy harvesting using L-shaped structures

2017 ◽  
Vol 29 (6) ◽  
pp. 1206-1215 ◽  
Author(s):  
Donghuan Liu ◽  
Mohammed Al-Haik ◽  
Mohamed Zakaria ◽  
Muhammad R Hajj
Keyword(s):  
Energy Harvesting ◽  
Power Density ◽  
Cantilever Beam ◽  
Strain Distribution ◽  
Uniform Strain ◽  
Main Beam ◽  
Piezoelectric Energy Harvesting ◽  
Frequency Range ◽  
Piezoelectric Energy

Energy harvesting from an L-shaped structure, formed by two beams and corner and end masses, is investigated with the objective of expanding the bandwidth of the frequency range over which energy can be harvested. The structure is excited in a direction that yields the most uniform strain distribution along its main beam. The length of the auxiliary beam is varied to determine its effect on the level and breadth of the frequency range over which energy can be harvested. Results from experiments having different geometries are presented and discussed. It is determined that the frequency range over which energy can be harvested from such structures is much larger than levels harvested when using a cantilever beam. The experiments also show that L-shaped structures harvest more power when the length of the auxiliary beam is increased. On the contrary, the power density of the L-shaped structure is much smaller than that of the cantilever beam. The ability to control the bandwidth of frequency over which energy is harvested through proper adjustment of beam lengths is demonstrated.

Critical Factors in Laser and Electron Beam Glazing of Materials.

1981 ◽  
Vol 8 ◽  
Author(s):  
P. R. Strutt ◽  
B. G. Lewis ◽  
B. H. Kear
Keyword(s):  
Electron Beam ◽  
Fluid Flow ◽  
Power Density ◽  
Interaction Time ◽  
Solidification Microstructure ◽  
Processing Conditions ◽  
Critical Factors ◽  
Absorbed Power ◽  
Flow Effects

ABSTRACTThe major effects of laser and electron beam glazing on solidification microstructure and melt zone geometry are described. It is shown that under comparable processing conditions, i.e. absorbed power density and interaction time, the glazed microstructures are similar. Some variations in microstructure of laser and electron beam glazed M2 steel have been noted, which seem to be related to fluid flow effects in the melt zone and possible interactions with the environment.

scholarly journals Analysis of Vase Shaped Pumping Cavity for Solar-Pumped Laser

2021 ◽  
Vol 25 (2) ◽  
pp. 242-247
Author(s):  
Hayato Koshiji ◽  
Tomomasa Ohkubo ◽  
Takumi Shimoyama ◽  
Takeru Nagai ◽  
Ei-ichi Matsunaga ◽  
...  
Keyword(s):  
Power Density ◽  
Absorption Rate ◽  
Laser Light ◽  
Laser System ◽  
Absorption Efficiency ◽  
Laser Medium ◽  
Power Density Distribution ◽  
Absorbed Power ◽  
Ray Tracing Simulation ◽  
Absorption Power

Although sunlight is a promising renewable energy source, the light is incoherent and difficult to use directly. Therefore, a solar-pumped laser, which directly converts sunlight into coherent laser light of, is a promising technology. A solar-pumped laser collects sunlight into the laser medium to realize laser oscillation. In order to realize an efficient solar-pumped laser system, it is necessary to design a pumping cavity that absorbs maximal sunlight into the laser medium with minimal thermal shock. In this research, the pumping cavity shape was studied using a numerical ray tracing simulation. As a result, it was found that a cone shaped pumping cavity can be expected to improve the absorption rate by approximately 30% over a cylindrically shaped pumping cavity. Furthermore, the absorption power density distribution can be flattened by a vase shaped pumping cavity, while maintaining the same absorption efficiency. The vase shaped pumping cavity has almost half the dispersion of the absorbed power density in the laser medium when compared with the cone shaped pumping cavity.

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