scholarly journals Comparison of Stress-Impedance Effect in Amorphous Ribbons with Positive and Negative Magnetostriction

Materials ◽  
2019 ◽  
Vol 12 (2) ◽  
pp. 275 ◽  
Author(s):  
Piotr Gazda ◽  
Michał Nowicki ◽  
Roman Szewczyk
Keyword(s):  
Tensile Stress ◽  
Frequency Dependence ◽  
Impedance Change ◽  
Dead Weight ◽  
Current Frequency ◽  
Reversal Point ◽  
Amorphous Ribbons ◽  
Sensing Material ◽  
Stress Sensing ◽  
Applied Stresses

The SI (stress-impedance) effect in amorphous ribbons with varying magnetostriction was investigated. Iron- and cobalt-based ribbons with different magnetostriction coefficients were put under tensile stress in a dead weight tester and the impedance change was investigated in function of applied stresses. Significant differences of characteristics are presented. Stress-impedance analog of Villari reversal point was observed. The reversal point showed driving current frequency dependence, in which this point manifests for different stress values. Based on the obtained SI characteristics and magnetoelastic hysteresis, the most appropriate stress-sensing material was selected for development of precise small forces sensor.

Magnetoimpedance and Field Sensitivity of CoFeSiB Amorphous Ribbons under Applied Tensile Stress

2015 ◽  
Vol 28 (7) ◽  
pp. 2059-2062 ◽  
Author(s):  
Mehrdad Moradi ◽  
Ali Dadsetan ◽  
Seyed Majid Mohseni ◽  
Ali Jazayeri Gharehbagh
Keyword(s):  
Tensile Stress ◽  
Amorphous Ribbons ◽  
Field Sensitivity ◽  
Applied Tensile Stress

scholarly journals Low Cost Non-İnvasive Portable Monitor Platform for Cardiac Biopotential and Transthoracic Impedance Measurements

2021 ◽  
Author(s):  
Oya Köksal ◽  
Erdem Haberal
Keyword(s):  
Reference Value ◽  
Raspberry Pi ◽  
Invasive Technique ◽  
Impedance Change ◽  
Thoracic Impedance ◽  
Current Frequency ◽  
Impedance Measurements ◽  
Non Invasive ◽  
Thoracic Electrical Bioimpedance ◽  
Electrical Bioimpedance

Abstract Purpose Simultaneous monitoring of ECG and thoracic electrical bioimpedance (TEB) is important in evaluating cardiovascular performance. TEB is a non-invasive technique based on measuring the impedance value that changes in the chest area depending on the heartbeat. Within the framework of this study, it can be used in home monitoring and biotelemetry applications to measure thoracic electrical bioimpedance (TEB), ECG and ICG. Methods Within the scope of this study, a four-electrode TEB measurement system was designed and built using the Raspberry Pi single board computer and its original monitor, ESP32 and EVAL-ADAS1000SDZ evaluation board. With the designed system, ECG and thoracic impedance measurements at 50 kHz current frequency were taken as real-time over a single channel. Delta_Z and ICG signals were created from thoracic impedance values with the developed software.ResultsWhile the thoracic impedance value varies between 15-45 Ω, the 67 thoracic impedance value measured with the designed system is approximately 1000 times the 68 reference value. The impedance change in the thoracic region was measured with the designed 69 system between 0.1-0.2 Ω values, and the compatibility of these values with reference values was 70 determined. While the reference value of the dZ / dt signal is 0.8 - 3.5 Ω / s, this value is between 2.3 - 71 5.3 Ω / s in the measurements taken with the designed system.Conclusion The prototype is achieved in detecting small changes in the thoracic impedance signal. The prototype is cheap, portable, small-sized and medically safe, so it is suitable for home care services and clinics. In addition, the developed system can be adapted to wearable technology. In order to increase the success of the system, the impedances values added to the thoracic impedance value should be determined and a calibration procedure should be established.

The role of intergranular precipitates in controlling creep cavitation

1980 ◽  
Vol 295 (1413) ◽  
pp. 307-307
Keyword(s):  
Surface Energy ◽  
Tensile Stress ◽  
Grain Boundaries ◽  
Stress Axis ◽  
Creep Cavitation ◽  
High Fraction ◽  
Work Done ◽  
Applied Stresses ◽  
Small Obstacle ◽  
Applied Tensile Stress

A satisfactory model for cavitational failure in creep must account for the fact that fracture can occur under a very low stress, for example, only 0.7 MPa for a solid solution magnesium alloy. A mechanism for growth based on the transfer of vacancies from high angle grain boundaries to intergranular cavities satisfies this low stress requirement for it converts a relatively high fraction of the work done by the applied load into surface energy of fracture. However, for such growth to proceed, cavity nuclei of radius greater than a critical value, r c , must exist on those grain boundaries which are approximately normal to the applied tensile stress axis. It can be shown quite simply that r c = 2y/o, where y is the surface energy per unit area and o the applied tensile stress. A typical value for r c is 1 pm which is far too large to occur spontaneously by chance accumulation of vacancies. It is in fact generally agreed that cohesion is lost owing to the concentration of stress at some small obstacle in a sliding grain boundary. These cavities are nucleated along the boundary under applied stresses which are lower than those needed to cause triple point cracking where the whole of the length of the boundary is available to concentrate stress. This was a puzzle until Smith & Barnby (1967) demonstrated that the stress concentrated at a small obstacle in a sliding boundary was far higher than that concentrated at a very large obstacle as incorporated in, for example, the Stroh derivation.

AC magnetoresistance and its frequency-dependence of Fe-doped Bi2Se3 topological insulator

2020 ◽  
Vol 34 (26) ◽  
pp. 2050276
Author(s):  
Qiya Liu ◽  
Ke Zhao ◽  
Xinsheng Yang ◽  
Yong Zhao
Keyword(s):  
Magnetic Field ◽  
Frequency Dependence ◽  
Topological Insulator ◽  
Magnetic Order ◽  
Skin Effect ◽  
Direct Method ◽  
Relaxation Mechanism ◽  
Current Frequency ◽  
Base Materials ◽  
A Direct Method

Bismuth selenide (Bi2Se3) is one of the most important base materials in the study of topological insulators. Doping with iron is a direct method to manipulate the magnetic order in Bi2Se3. In this paper, we first report the measurements of magnetoresistance of Fe-doped Bi2Se3 with alternating current. Unlike the DC magnetoresistance, skin effect plays an important role in AC magnetoresistance. Another interesting finding is that resonance occurs at a certain frequency, which implies an internal relaxation mechanism. The relations between resistance, magnetic field and current frequency are discussed.

scholarly journals Stress Dependence of the Small Angle Magnetization Rotation Signal in Commercial Amorphous Ribbons

Materials ◽  
2019 ◽  
Vol 12 (18) ◽  
pp. 2908 ◽  
Author(s):  
Michał Nowicki
Keyword(s):  
Tensile Stress ◽  
Small Angle ◽  
Force Sensor ◽  
Stress Dependence ◽  
Soft Magnetic ◽  
Magnetization Rotation ◽  
Amorphous Ribbons ◽  
Supply Current ◽  
Rotation Signal

The results of the investigation on tensile stress dependence of the SAMR (small angle magnetization rotation) signal in soft magnetic amorphous ribbons are presented. Exemplary results for commercially available, negatively magnetostrictive 2705M, 2714A, and 6030D amorphous ribbons show significant stress dependence, in contrast to positively magnetostrictive 2826MB alloy. The magnetoelastic hysteresis of the obtained characteristics is compared, as well as the influence of the biasing H field and supply current variations. Based on the results, 2705M alloy with near-zero negative magnetostriction is proposed as best suited for a SAMR-based, magnetoelastic force sensor.

scholarly journals An Innovative Smart Concrete Anchorage with Self-Stress Sensing Capacity of Prestressing Stress of PS Tendon

Sensors ◽  
2021 ◽  
Vol 21 (15) ◽  
pp. 5251
Author(s):  
Seon Yeol Lee ◽  
Huy Viet Le ◽  
Min Kyoung Kim ◽  
Dong Joo Kim ◽  
Jongwoong Park
Keyword(s):  
Tensile Stress ◽  
High Performance ◽  
Electrode Materials ◽  
High Performance Concrete ◽  
Copper Wire ◽  
Steel Slag ◽  
Ultra High Performance Concrete ◽  
Stress Sensing ◽  
Prestressing Loss ◽  
Smart Concrete

An innovative smart concrete anchorage (SCA) has been developed for monitoring the stress of prestressing (PS) tendons by utilizing smart ultra-high-performance concrete (UHPC). The smart UHPC contained 2 vol% steel fibers and fine steel slag aggregates instead of silica sands. The effects of different electrode materials, arrangements, and connectors on the self-stress sensing capacity of the SCA are discussed. A prototype SCA demonstrated its feasibility and sufficient self-stress sensing capacity to be used in monitoring the prestressing loss of the PS tendon. As the tensile stress of the PS tendon increased from 0 to 1488 MPa, the fractional change in resistivity (FCR) of the prototype SCA, with horizontally paired copper wire electrodes and a plug-in type connector, decreased linearly from 0% to −1.53%, whereas the FCR increased linearly from −1.53% to −0.04% as the tensile stress of the PS tendon decreased from 1488 to 331 MPa.

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