scholarly journals EBG waveguides for contactless surface impedance measurements

2021 ◽  
Vol 2015 (1) ◽  
pp. 012030
Author(s):  
Sandra Rodini ◽  
Simone Genovesi ◽  
Giuliano Manara ◽  
Filippo Costa
Keyword(s):  
Surface Impedance ◽  
Direct Contact ◽  
Thin Sheet ◽  
Air Gap ◽  
Scattering Parameters ◽  
Thin Sample ◽  
Waveguide Section ◽  
Impedance Measurements ◽  
Inversion Procedure

Abstract A method for the estimation of sheet impedance of thin sample which does not require a direct contact with the sample under test is proposed. The surface impedance is calculated through an inversion procedure exploiting the scattering parameters obtained through a waveguide measurement setup. An inversion procedure based on the representation of the waveguide-air-waveguide section as a π junction is employed. In order to prevent the field leakage from the air gap created for hosting the thin sheet, an EBG surface is introduced on the flange of the waveguide. It is shown that the introduction of the EBG surface remarkably improves the estimation of the surface impedance of the thin sheet with respect to the case without EBG.

Surface impedance measurements of cuprate superconductors: Nd1.85.85Ce0.15CuO4?? ?A case study

1994 ◽  
Vol 7 (2) ◽  
pp. 453-458 ◽  
Author(s):  
Steven M. Anlage ◽  
Dong -Ho Wu ◽  
Jian Mao ◽  
Sining Mao ◽  
X. X. Xi ◽  
...  
Keyword(s):  
Surface Impedance ◽  
Cuprate Superconductors ◽  
Impedance Measurements

scholarly journals A Comparison Study of Brine Desalination using Direct Contact and Air Gap Membrane Distillation

2019 ◽  
Vol 25 (11) ◽  
pp. 47-54
Author(s):  
Ahmed Shamil Khalaf ◽  
Asrar Abdullah Hassan
Keyword(s):  
Flow Rate ◽  
Direct Contact ◽  
Polyvinylidene Fluoride ◽  
Membrane Distillation ◽  
Air Gap ◽  
Feed Flow Rate ◽  
Permeate Flux ◽  
Air Gap Membrane Distillation ◽  
Flat Sheet ◽  
Feed Temperature

Membrane distillation (MD) is a hopeful desalination technique for brine (salty) water. In this research, Direct Contact Membrane Distillation (DCMD) and  Air Gap Membrane Distillation (AGMD) will be used. The sample used is from Shat Al –Arab water (TDS=2430 mg/l). A polyvinylidene fluoride (PVDF) flat sheet membrane was used as a flat sheet form with a plate and frame cell. Several parameters were studied, such as; operation time, feed temperature, permeate temperature, feed flow rate. The results showed that with time, the flux decreases because of the accumulated fouling and scaling on the membrane surface. Feed temperature and feed flow rate had a positive effect on the permeate flux, while permeate temperature had a reverse effect on permeate flux. It is noticeable that the flux in DCMD is greater than AGMD, at the same conditions. The flux in DCMD is 10.95LMH, and that in AGMD is 7.14 LMH.  In AGMD, the air gap layer made a high resistance. Here the temperature transport reduces in the permeate side of AGMD due to the air gap resistance. The heat needed for AGMD is lower than DCMD, this leads to low permeate flux because the temperature difference between the two sides is very small, so the driving force (vapor pressure) is low.                                                                                               

Surface impedance measurements and calculations according to the Mattis-Bardeen theory on high-T/sub c/ superconductors

1991 ◽  
Vol 27 (2) ◽  
pp. 1302-1305
Author(s):  
N.D. Kataria ◽  
R. Popel ◽  
H. Wolf ◽  
H. Sachse ◽  
T. Kuhlemann ◽  
...  
Keyword(s):  
Surface Impedance ◽  
Impedance Measurements

Modeling of Air-Gap Membrane Distillation and Comparative Study with Direct Contact Membrane Distillation

2020 ◽  
Vol 59 (50) ◽  
pp. 21930-21947
Author(s):  
Sadaf Noamani ◽  
Shirin Niroomand ◽  
Masoud Rastgar ◽  
Mehdi Azhdarzadeh ◽  
Mohtada Sadrzadeh
Keyword(s):  
Comparative Study ◽  
Direct Contact ◽  
Membrane Distillation ◽  
Air Gap ◽  
Air Gap Membrane Distillation ◽  
Direct Contact Membrane Distillation

Error estimation due to sample size effects of in situ surface impedance measurements.

2010 ◽  
Vol 127 (3) ◽  
pp. 2001-2001
Author(s):  
Eric Brandao ◽  
Erico Fulco ◽  
Arcanjo Lenzi ◽  
Emiel Tijs
Keyword(s):  
Sample Size ◽  
Error Estimation ◽  
Size Effects ◽  
Surface Impedance ◽  
Impedance Measurements

scholarly journals VLF surface-impedance measurements for ice-depth mapping — an assessment of some commonly encountered interference effects

1996 ◽  
Vol 42 (140) ◽  
pp. 33-36 ◽  
Author(s):  
David V. Thiel ◽  
Daniel James ◽  
Peter Johnson
Keyword(s):  
Surface Impedance ◽  
Apparent Resistivity ◽  
Low Frequency ◽  
Two Dimensional ◽  
Interference Effects ◽  
Impedance Measurements ◽  
Very Low Frequency ◽  
Dimensional Boundary ◽  
Lateral Variations ◽  
Made In

AbstractThe effects on very low-frequency surface-impedence measurements of lateral variations commonly found in ice environments have been measured and modelled numerically using die quasi-static two-dimensional boundary-element method. Results indicate that surface-impedance measurements made in the vicinity of crevasses oriented perpendicular to the plane Of incidence, and those made in the vicinity of moraines and melt streams, can all show significant changes to the measured apparent resistivity. It is, therefore, misleading to use such measurements in the interpretation of ice depth.

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