Torsional dependence of second-harmonic amplitude of giant magnetoimpedance in FeCoSiB amorphous wire

2002 ◽  
Vol 38 (5) ◽  
pp. 3087-3089 ◽  
Author(s):  
C. Losin ◽  
C. Gomez-Polo ◽  
M. Knobel ◽  
A. Grishin
Keyword(s):  
Second Harmonic ◽  
Amorphous Wire ◽  
Harmonic Amplitude ◽  
Giant Magnetoimpedance

scholarly journals A Combination of a Vibrational Electromagnetic Energy Harvester and a Giant Magnetoimpedance (GMI) Sensor

Sensors ◽  
2020 ◽  
Vol 20 (7) ◽  
pp. 1873
Author(s):  
Juan Jesús Beato-López ◽  
Isaac Royo-Silvestre ◽  
José María Algueta-Miguel ◽  
Cristina Gómez-Polo
Keyword(s):  
Permanent Magnets ◽  
Energy Harvester ◽  
Vibrational Energy ◽  
Magnetic Levitation ◽  
Low Cost ◽  
Mechanical Vibration ◽  
Inertial Mass ◽  
Amorphous Wire ◽  
Magnetic Element ◽  
Giant Magnetoimpedance

An energy harvesting device combined with a giant magnetoimpedance (GMI) sensor is presented to analyze low frequency vibrating systems. An electromagnetic harvester based on magnetic levitation is proposed for the electric power generation. The device is composed of two fixed permanent magnets at both ends of a cylindrical frame, a levitating magnet acting as inertial mass and a pick-up coil to collect the induced electromotive force. At the resonance frequency (10 Hz) a maximum electrical power of 1.4 mW at 0.5 g is generated. Moreover, an amorphous wire was employed as sensor nucleus for the design of a linear accelerometer prototype. The sensor is based on the GMI effect where the impedance changes occur as a consequence of the variations of the effective magnetic field due to an oscillating magnetic element. As a result of the magnet’s periodic motion, an amplitude modulated signal (AM) was obtained, its amplitude being proportional to mechanical vibration amplitude (or acceleration). The sensor’s response was examined for a simple ferrite magnet under vibration and compared with that obtained for the vibrational energy harvester. As a result of the small amplitudes of vibration, a linear sensor response was obtained that could be employed in the design of low cost and simple accelerometers.

Nonlinear Ultrasonic Techniques for Testing Micro-Defects in Metal Matrix Composite Structure

2011 ◽  
Vol 483 ◽  
pp. 784-788
Author(s):  
Yi Dun ◽  
Shuan Jie Wang ◽  
Xiao Hong Shi ◽  
Zhao Ying Zhou
Keyword(s):  
Metal Matrix Composite ◽  
Matrix Composite ◽  
Composite Structure ◽  
Acoustic Waves ◽  
Metal Matrix ◽  
Amplitude Ratio ◽  
Second Harmonic ◽  
Harmonic Amplitude ◽  
Acoustic Features ◽  
Nonlinear Acoustic

Micro-defects inside metal matrix composite structure seriously influence the mechanic properties of materials and can undermine machine operations. In order to detect the micro-defects, we can make use of one of the nonlinear acoustic features, i.e., harmonics, which usually appear together with ultrasound when propagating through a damaged material. Based on the relationship between the harmonics, a method of using nonlinear acoustic harmonic amplitude ratio to distinguish micro-defects in metal matrix composite structure is discussed. The test results show that acoustic features, such as second harmonic excitation efficiency were very obvious for the damaged group samples. The method presented is effective in detecting the micro-defects, which means that nonlinear acoustic waves may provide us a good solution for quantitative evaluation of the early damages in metal matrix composite structure.

scholarly journals Laser second-harmonic generation from an overdense plasma slab

2017 ◽  
Vol 35 (3) ◽  
pp. 379-385
Author(s):  
M. Kaur ◽  
P. C. Agarwal ◽  
S. Kaur
Keyword(s):  
Second Harmonic ◽  
Short Pulse ◽  
Specular Reflection ◽  
Plasma Boundary ◽  
Harmonic Amplitude ◽  
Angle Of Incidence ◽  
Multiple Reflections ◽  
Short Pulse Laser ◽  
Plasma Slab ◽  
Overdense Plasma

AbstractA s-polarized short-pulse laser impinged obliquely on an overdense plasma slab is shown to produce very significant second harmonic in the direction of specular reflection and transmission. The laser induces a non-linear current on electrons, which is curl free. However, with sharp plasma boundary, it gives rise to electromagnetic radiation at the second harmonic. Our formalism includes multiple reflections of the incident and second-harmonic waves from both the front and rear surfaces. The present work includes finiteness of the slab. The normalized second-harmonic amplitude acquires a sharp peak at some specific angle of incidence for a particular set of parameters dependent on thickness of the slab and plasma density.

Bias Current Effect on Nonlinear Magnetoimpedance Response in Amorphous Wires with Circular Anisotropy

2009 ◽  
Vol 152-153 ◽  
pp. 329-332
Author(s):  
N.A. Buznikov ◽  
A.S. Antonov ◽  
A.A. Rakhmanov
Keyword(s):  
Skin Effect ◽  
Second Harmonic ◽  
Bias Current ◽  
Voltage Response ◽  
Harmonic Amplitude ◽  
Current Effect ◽  
Rotational Model ◽  
Amorphous Wires ◽  
Field Sensitivity ◽  
Maximum Field

The effect of bias current on the appearance of higher harmonics in the nonlinear mag¬netoimpedance in amorphous wires with a circular anisotropy is studied. The rotational model to calculate the voltage response in the case of a weak skin effect is proposed. It is shown that the ap¬plication of the bias current may lead to significant increase of the second harmonic amplitude in the voltage. The conditions of maximum field sensitivity of the second harmonic are found.

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