Characterization of an experimental wavenumber fitting method for loss factor estimation using a viscoelastically damped structure

2006 ◽  
Vol 291 (3-5) ◽  
pp. 1170-1185 ◽  
Author(s):  
Vikrant Palan ◽  
W. Steve Shepard ◽  
J. Gregory McDaniel
Keyword(s):  
Loss Factor ◽  
Fitting Method ◽  
Factor Estimation

Thermodynamic characterization of the power loss factor in steam turbines

2002 ◽  
Vol 43 (17) ◽  
pp. 2369-2378 ◽  
Author(s):  
Alejandro Zaleta-Aguilar ◽  
Luis F Vega ◽  
Armando Gallegos-Muñoz ◽  
Abel Hernández-Guerrero
Keyword(s):  
Loss Factor ◽  
Power Loss ◽  
Steam Turbines ◽  
Thermodynamic Characterization

scholarly journals Characterization of the Vortex Beam by Fermat’s Spiral

Photonics ◽  
2020 ◽  
Vol 7 (4) ◽  
pp. 102
Author(s):  
Ewa Frączek ◽  
Agnieszka Popiołek-Masajada ◽  
Sławomir Szczepaniak
Keyword(s):  
Phase Distribution ◽  
Phase Plate ◽  
Vortex Beam ◽  
Scanning Microscope ◽  
Object Beam ◽  
Fitting Method ◽  
Numerical Fitting ◽  
Helical Beam ◽  
Spiral Phase

In this paper, we characterize the helical beam structure through an analysis of the spiral character of the phase distribution inside a light beam. In particular, we show that a line connected with the 2π phase jump in the Laguerre–Gauss beam can be described by a Fermat’s spiral. We propose a numerical fitting method to determine the parameters of a spiral equation for the phase distribution of the helical beam. Next, we extend the procedure to a vortex beam created by the spiral phase plate and apply it to experimental phase maps, which allows us to recover the phase shift introduced into the object beam in the optical vortex scanning microscope.

Fabrication and characterization of highly controllable magnetorheological material in compression mode

2020 ◽  
Vol 31 (14) ◽  
pp. 1641-1661 ◽  
Author(s):  
Amin Fereidooni ◽  
Afonso Martins ◽  
Viresh Wickramasinghe ◽  
Afzal Suleman
Keyword(s):  
Magnetic Fields ◽  
Loss Factor ◽  
Magnetorheological Fluid ◽  
Loading Frequency ◽  
Magnetorheological Elastomer ◽  
Magnetorheological Elastomers ◽  
Equivalent Damping ◽  
Magnetorheological Effect ◽  
Equivalent Damping Coefficient

This article is focused on the development and characterization of highly controllable magnetorheological materials for stiffness and damping control in semi-active control applications. Two types of magnetorheological materials are developed in-house: magnetorheological elastomer with soft base elastomer, and magnetorheological fluid encapsulated in regular elastomer, namely magnetorheological fluid-elastomer. In both cases of magnetorheological elastomers and magnetorheological fluid-elastomers, the samples are evaluated using in-house-developed shear and compression test rigs, which are equipped with electromagnets and Hall effect sensors for measuring the magnetic field. These features provide the capability to precisely control a wide range of magnetic fields during the experiments. In the case of magnetorheological elastomers, the experimental results of the in-house magnetorheological elastomers are compared with commercially available counterparts made of hard base elastomer. It is shown that the controllability of the material, that is, the relative magnetorheological effect, is significantly improved in the case of magnetorheological elastomer with soft base elastomer. In addition to various magnetic fields, the samples are subjected to a range of loading amplitudes and frequencies. A general trend is observed where the frequency and strain amplitude cause an opposite effect on both the shear and compressive moduli: the increase in frequency gives rise to a higher value of modulus whereas the increase in amplitude reduces the modulus. Furthermore, the effect of bonding on the performance of the magnetorheological elastomers in compression mode is evaluated and the results indicate a significant increase in the modulus and decrease in the loss factor. In all the cases, however, the change of loss factor does not exhibit a predictable trend as a function of magnetic fields. In order to investigate a magnetorheological-based solution for controlling the damping of a semi-active system, magnetorheological fluid-elastomer samples are made in-house. These samples are fabricated using three different iron concentrations, and are tested in compression (squeeze) mode. The results of these experiments confirm that the equivalent damping coefficient of the material rises with the increase in magnetic field, and this effect becomes stronger as the iron concentration of magnetorheological fluids increases. It is also demonstrated that the magnetorheological effect is highly dependent on the loading frequency and amplitude, where the equivalent damping coefficient decreases with the increase in loading frequency and amplitude. In all the aforementioned cases, the stiffness of magnetorheological fluid-elastomers exhibits minor changes, which offers the in-house-developed magnetorheological fluid-elastomers as a damping only control option, a development that is different from the magnetorheological fluid-elastomers reported in the literature.

Characterization and Formulation of Microstrip-Slot Impedance with Different Thickness and Relative Permittivity

2015 ◽  
Vol 781 ◽  
pp. 53-56
Author(s):  
Khairul Huda Yusof ◽  
Norhudah Seman ◽  
Mohd Haizal Jamaluddin ◽  
D.N.A. Zaidel
Keyword(s):  
Curve Fitting ◽  
Relative Permittivity ◽  
Slot Line ◽  
Fitting Method ◽  
Curve Fitting Method ◽  
Different Thickness ◽  
Cst Microwave Studio

This paper presents the characterization of a microstrip-slot line in terms of its impedance and dimension. The characterization is made by referring to the analysis of different relative permittivity and thicknesses of substrates, which conducted by using CST Microwave Studio. Based on the characterization with the use of completing square curve fitting method, new formulated equations are proposed for microstrip-slot line. These formulated equations are suitable for thin substrate with low relative permittivity. The characterization is made based on the substrates with the selected thickness of 0.508 mm, 0.762 mm and 1.542 mm, for relative permittivity of 4.5 (TMM4), 3.38 (RO 4003C) and 2.94 (RT 6002).

scholarly journals Characterization of Thick Film Capicitors

1977 ◽  
Vol 4 (3-4) ◽  
pp. 125-131
Author(s):  
Y. Leroy ◽  
M. Descamps ◽  
M. Vernet
Keyword(s):  
Thick Film ◽  
Loss Factor ◽  
Training Period ◽  
Electrical Parameters ◽  
Teaching Activities ◽  
Measurement Results

Teaching activities of the “Institut Universitaire de Technologie de Lille” (France) were previously reported.The present paper reports measurement results obtained by students during their last training period for about a hundred capacitors made with commercial dielectrics (EMCA CDP 400, EMCA CDP 2000, and ESL K 1000).We examine the following points: reproducibility of capacitors during fabrication, correlation between electrical parameters of components and firing conditions, measurements of capacitance and loss factor between 10 kHz and 20 MHz for temperatures ranging from 20°C to 100°C.

scholarly journals A Prony-based curve-fitting method for characterization of RF pulses from optoelectronic devices

2021 ◽  
pp. 1-1
Author(s):  
Saptarshi Mukherjee ◽  
Karen M Dowling ◽  
Yicong Dong ◽  
Kexin Li ◽  
Adam Conway ◽  
...  
Keyword(s):  
Curve Fitting ◽  
Optoelectronic Devices ◽  
Rf Pulses ◽  
Fitting Method ◽  
Curve Fitting Method
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