Magnetomechanical Properties of Circumferentially Field-Annealed Metglas® 2605SC Cylinders

1994 ◽  
Vol 360 ◽  
Author(s):  
J. B. Restorff ◽  
M. Wun-Fogle ◽  
A. E. Clark ◽  
Thu-Van T. Luu
Keyword(s):  
Coupling Coefficient ◽  
Longitudinal Mode ◽  
Bias Field ◽  
Coupling Coefficients ◽  
Effective Coupling ◽  
Impedance Measurements ◽  
Annealing Temperatures ◽  
Large Numbers ◽  
Demagnetizing Factor ◽  
A Current

AbstractWe have measured the magnetomechanical coupling coefficient of Metglas®2605SC (Fe81B13.5C2) ribbons that were annealed into 1.27 and 0.8 cm diameter cylinders. Lengths ranged from 0.6 to 5 cm. A novel furnace was constructed in which a cylindrical magnetic field was supplied by a current carrying copper rod. During the annealing, a 300 A current created a circumferential field of more than 6400 A/m. Annealing temperatures ranged from 380 to 420 ºC. Large shifts in both the optimum bias field and the coupling coefficient as a function of length and diameter were found due to demagnetizing effects. Impedance vs. frequency measurements show large numbers of modes, some of which are field dependent. Effective coupling coefficientsof the lowest order longitudinal mode were calculated from impedance measurements by using k2 = 1-f2r/f2a, where fr, and fa. are the resonant and antiresonant frequencies respectively. Coupling coefficients for 5 cm long cylinders were as high as 0.58. When the demagnetizing factor is taken into account, we find material coupling coefficients as high as 0.89.

Modeling the Atmospheric Boundary Layer Wind Response to Mesoscale Sea Surface Temperature Perturbations

2014 ◽  
Vol 142 (11) ◽  
pp. 4284-4307 ◽  
Author(s):  
Natalie Perlin ◽  
Simon P. de Szoeke ◽  
Dudley B. Chelton ◽  
Roger M. Samelson ◽  
Eric D. Skyllingstad ◽  
...  
Keyword(s):  
Boundary Layer ◽  
Wind Speed ◽  
Surface Temperature ◽  
Sea Surface Temperature ◽  
Coupling Coefficient ◽  
Eddy Viscosity ◽  
Sea Surface ◽  
Coupling Coefficients ◽  
Wind Response ◽  
Speed Response

Abstract The wind speed response to mesoscale SST variability is investigated over the Agulhas Return Current region of the Southern Ocean using the Weather Research and Forecasting (WRF) Model and the U.S. Navy Coupled Ocean–Atmosphere Mesoscale Prediction System (COAMPS) atmospheric model. The SST-induced wind response is assessed from eight simulations with different subgrid-scale vertical mixing parameterizations, validated using Quick Scatterometer (QuikSCAT) winds and satellite-based sea surface temperature (SST) observations on 0.25° grids. The satellite data produce a coupling coefficient of sU = 0.42 m s−1 °C−1 for wind to mesoscale SST perturbations. The eight model configurations produce coupling coefficients varying from 0.31 to 0.56 m s−1 °C−1. Most closely matching QuikSCAT are a WRF simulation with the Grenier–Bretherton–McCaa (GBM) boundary layer mixing scheme (sU = 0.40 m s−1 °C−1), and a COAMPS simulation with a form of Mellor–Yamada parameterization (sU = 0.38 m s−1 °C−1). Model rankings based on coupling coefficients for wind stress, or for curl and divergence of vector winds and wind stress, are similar to that based on sU. In all simulations, the atmospheric potential temperature response to local SST variations decreases gradually with height throughout the boundary layer (0–1.5 km). In contrast, the wind speed response to local SST perturbations decreases rapidly with height to near zero at 150–300 m. The simulated wind speed coupling coefficient is found to correlate well with the height-averaged turbulent eddy viscosity coefficient. The details of the vertical structure of the eddy viscosity depend on both the absolute magnitude of local SST perturbations, and the orientation of the surface wind to the SST gradient.

scholarly journals Differential Bi-Level Microstrip Directional Coupler with Equalized Coupling Coefficients for Directivity Improvement

Electronics ◽  
2020 ◽  
Vol 9 (4) ◽  
pp. 547
Author(s):  
Slawomir Gruszczynski ◽  
Robert Smolarz ◽  
Krzysztof Wincza
Keyword(s):  
Coupling Coefficient ◽  
Dielectric Layer ◽  
Directional Coupler ◽  
Capacitive Coupling ◽  
Coupling Coefficients ◽  
Coupled Line ◽  
Line Section ◽  
Measurement Results

In this paper, a bi-level microstrip differential directional coupler has been investigated. It has been shown that the equalization of coupling coefficients can be successfully made with the use of appropriate dielectric stack-up and conductor geometry. The application of additional top dielectric layer can ensure proper equalization of coupling coefficients by lowering the value of capacitive coupling coefficient to the value of the inductive one. The theoretically investigated coupled-line section has been used for the design of a 3-dB differential directional coupler. The measurement results are compared with the theoretical ones.

Microstructure and Electrical Properties of Lead-Free (Na0.5K0.5)NbO3 - Bi0.5(Na0.97K0.03)0.5TiO3 Ceramics

2013 ◽  
Vol 368-370 ◽  
pp. 760-763
Author(s):  
Chun Huy Wang ◽  
Ming Qiu Wei
Keyword(s):  
Electrical Properties ◽  
Coupling Coefficient ◽  
Electromechanical Coupling ◽  
Piezoelectric Properties ◽  
Coupling Coefficients ◽  
X Ray Diffraction ◽  
X Ray ◽  
Dense Microstructure ◽  
Dielectric And Piezoelectric Properties ◽  
Thickness Mode

(Na0.5K0.5)NbO3 with Bi0.5(Na0.97K0.03)0.5TiO3 with x≤0.05 has been prepared by the conventional mixed oxide process. X-ray diffraction analysis revealed that, during sintering, all the Bi(Na0.97K0.03)TiO3 diffuses into the lattice of (Na0.5K0.5)NbO3 to form a solid solution with a perovskite structure. A morphotropic phase boundary (MPB) between orthorhombic (O) and rhombohedral (R) was found at the composition 0.98(Na0.5K0.5)NbO3-0.02Bi0.5(Na0.97K0.03)0.5TiO3 [abbreviated as 0.98NKN-0.02BNKT] with correspondingly enhanced dielectric and piezoelectric properties. For 0.98NKN-0.02BNKT ceramics, the electromechanical coupling coefficients of the planar mode kp and the thickness mode kt reach 0.33 and 0.49, respectively, after sintering at 1100 oC for 3 h. The ratio of the thickness coupling coefficient to the planar coupling coefficient is 1.48. With suitable Bi0.5(Na0.97K0.03)0.5TiO3 concentration, a dense microstructure and good electrical properties are obtained.

Effect of Bi2O3 Addition on the Electrical and Physical Properties of Lead-Free 0.98(Na0.5K0.5)NbO3-0.02 Ba(Zr0.04Ti0.96)O3 Piezoelectric Ceramics

2010 ◽  
Vol 434-435 ◽  
pp. 413-416 ◽  
Author(s):  
Chun Huy Wang
Keyword(s):  
Coupling Coefficient ◽  
Electromechanical Coupling ◽  
Orthorhombic Phase ◽  
Lead Free ◽  
Coupling Coefficients ◽  
X Ray Diffraction ◽  
Sintering Aid ◽  
X Ray ◽  
Thickness Mode ◽  
Planar Mode

The 0.98(Na0.5K0.5)NbO3–0.02Ba(Zr0.04Ti0.96)O3 ceramics have been prepared following the conventional mixed oxide process. X-ray diffraction analysis revealed that, during sintering, all of the Ba(Zr0.04Ti0.96)O3 diffuses into the lattice of (Na0.5K0.5)NbO3 to form a solid solution, in which a orthorhombic phase with a perovskite structure was found In order to improve the sinterability of the ceramics, Bi2O3 additions were used as a sintering aid. The electromechanical coupling coefficients of the planar mode kp and the thickness mode kt reach 0.3 and 0.55, respectively, at the sintering of 1100oC for 5 h. For 0.98NKN-0.02BZT ceramics by doping 0.5 wt.% Bi2O3, the electromechanical coupling coefficients of the planar mode kp and the thickness mode kt reach 0.21 and 0.57, respectively. The ratio of thickness coupling coefficient to planar coupling coefficient is 2.7.

scholarly journals Effect of Tensile Force on Magnetostrictive Sensors for Generating and Receiving Longitudinal Mode Guided Waves in Steel Wires

2019 ◽  
Vol 2019 ◽  
pp. 1-8 ◽  
Author(s):  
Jiang Xu ◽  
Yong Li ◽  
Guang Chen
Keyword(s):  
Magnetic Field ◽  
Coupling Coefficient ◽  
Guided Waves ◽  
Steel Wire ◽  
Tensile Force ◽  
Longitudinal Mode ◽  
Effective Field ◽  
Bias Magnetic Field ◽  
Magnetostrictive Sensor ◽  
The Relationship

When the longitudinal mode guided waves based on magnetostrictive effect were employed to inspect the bridge cables, we found that there was a large difference in the signal’s amplitude of the same specification cable under different tensile force. This difference would affect the test results and the identification of defects. It is necessary to study the effect of tensile force on the signal for the reliability of detection. Firstly, the effective field theory is employed to take the force as an additional bias magnetic field. Then, the effect of the tensile force on generating and receiving longitudinal mode guided waves based on magnetostrictive effect is obtained by the relationship between the bias magnetic field and the magnetostrictive coupling coefficient. Finally, the experiment of the magnetostrictive sensor is carried out on a Φ5 mm steel wire under different force. The experimental results are in good agreement with the theoretical results. The results show that the existence of the tensile force would change the operation point for generating and receiving the longitudinal mode guided waves based on magnetostrictive effect, which associated with the coupling coefficient. In order to obtain the optimal conversion efficiency for the force state wire and cable, the applied bias magnetic field should be set smaller than the bias magnetic field for the force-free state.

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