Theory of capacitive probe method for noncontact characterization of dielectric properties of materials

1991 ◽  
Vol 6 (3) ◽  
pp. 629-638 ◽  
Author(s):  
V.K. Tewary ◽  
P.R. Heyliger ◽  
A.V. Clark
Keyword(s):  
Experimental Data ◽  
Potential Distribution ◽  
Dielectric Material ◽  
Dielectric Materials ◽  
Probe Method ◽  
Capacitive Probe ◽  
Properties Of Materials ◽  
Element Technique ◽  
The Hilbert Transform

The capacitive probe method for noncontact characterization and monitoring of dielectric materials is analyzed theoretically. An analytical method based upon the Hilbert transform technique and a numerical method using the finite element technique for calculating the potential distribution and change in admittance of the probe caused by presence of the dielectric material as a function of liftoff (distance between the probe plane and the surface of the dielectric material) are described. The two methods are compared with each other and their relative advantages discussed. The possibility of extracting useful information about the dielectric constant of the material from experimental data is also discussed in the light of the proposed theory.

Characterization of Brightness of ZnS Electroluminescent Device with Dielectric Materials of SOG or TEOS

2008 ◽  
Vol 55 ◽  
pp. 160-163
Author(s):  
Sung Min Park ◽  
Mun Ja Kim ◽  
Sang Hyun Park ◽  
Jin Young Kim ◽  
Ji Beom Yoo
Keyword(s):  
Spin Coating ◽  
Dielectric Material ◽  
Dielectric Materials ◽  
Organic Binder ◽  
Layer Formation ◽  
Phosphor Layer ◽  
Electroluminescent Device ◽  
Coating Method ◽  
Powder Type

Spin on glass (SOG) and Tetraethylorthosilicate (TEOS) as a dielectric material were applied for inorganic powder type electroluminescent (EL) device. The spin coating method was used for the SOG layer or TEOS layer formation and phosphor layer formation. The phosphor layer was composed of ZnS:Cu,Cl powders and organic binder. The brightness of powder EL has been measured.

Mathematical model to predict the characteristics of polarization in dielectric materials: The concept of piezoelectrcity and electrostriction

2019 ◽  
Author(s):  
Chem Int
Keyword(s):  
Mathematical Model ◽  
Electric Field ◽  
Lead Zirconate Titanate ◽  
Dielectric Material ◽  
Strain Curve ◽  
Dielectric Materials ◽  
Lead Zirconate ◽  
Simulation Software ◽  
Constitutive Law ◽  
Basic Material

Model was developed for the prediction of polarization characteristics in a dielectric material exhibiting piezoelectricity and electrostriction based on mathematical equations and MATLAB computer simulation software. The model was developed based on equations of polarization and piezoelectric constitutive law and the functional coefficient of Lead Zirconate Titanate (PZT) crystal material used was 2.3×10-6 m (thickness), the model further allows the input of basic material and calculation of parameters of applied voltage levels, applied stress, pressure, dielectric material properties and so on, to generate the polarization curve, strain curve and the expected deformation change in the material length charts. The mathematical model revealed that an application of 5 volts across the terminals of a 2.3×10-6 m thick dielectric material (PZT) predicted a 1.95×10-9 m change in length of the material, which indicates piezoelectric properties. Both polarization and electric field curve as well as strain and voltage curve were also generated and the result revealed a linear proportionality of the compared parameters, indicating a resultant increase in the electric field yields higher polarization of the dielectric materials atmosphere.

scholarly journals Influence of the Porosity of Polymer Foams on the Performances of Capacitive Flexible Pressure Sensors

Sensors ◽  
2019 ◽  
Vol 19 (9) ◽  
pp. 1968 ◽  
Author(s):  
Sylvie Bilent ◽  
Thi Hong Nhung Dinh ◽  
Emile Martincic ◽  
Pierre-Yves Joubert
Keyword(s):  
Experimental Data ◽  
Linear Model ◽  
Dielectric Material ◽  
Pressure Sensors ◽  
Volume Ratio ◽  
Measurement Range ◽  
Polymer Foams ◽  
First Order ◽  
Non Linear ◽  
Flexible Pressure Sensors

This paper reports on the study of microporous polydimethylsiloxane (PDMS) foams as a highly deformable dielectric material used in the composition of flexible capacitive pressure sensors dedicated to wearable use. A fabrication process allowing the porosity of the foams to be adjusted was proposed and the fabricated foams were characterized. Then, elementary capacitive pressure sensors (15 × 15 mm2 square shaped electrodes) were elaborated with fabricated foams (5 mm or 10 mm thick) and were electromechanically characterized. Since the sensor responses under load are strongly non-linear, a behavioral non-linear model (first order exponential) was proposed, adjusted to the experimental data, and used to objectively estimate the sensor performances in terms of sensitivity and measurement range. The main conclusions of this study are that the porosity of the PDMS foams can be adjusted through the sugar:PDMS volume ratio and the size of sugar crystals used to fabricate the foams. Additionally, the porosity of the foams significantly modified the sensor performances. Indeed, compared to bulk PDMS sensors of the same size, the sensitivity of porous PDMS sensors could be multiplied by a factor up to 100 (the sensitivity is 0.14 %.kPa−1 for a bulk PDMS sensor and up to 13.7 %.kPa−1 for a porous PDMS sensor of the same dimensions), while the measurement range was reduced from a factor of 2 to 3 (from 594 kPa for a bulk PDMS sensor down to between 255 and 177 kPa for a PDMS foam sensor of the same dimensions, according to the porosity). This study opens the way to the design and fabrication of wearable flexible pressure sensors with adjustable performances through the control of the porosity of the fabricated PDMS foams.

scholarly journals Characterization of Dielectric Materials by Sparse Signal Processing With Iterative Dictionary Updates

2020 ◽  
Vol 4 (9) ◽  
pp. 1-4
Author(s):  
Udaya S. K. P. Miriya Thanthrige ◽  
Jan Barowski ◽  
Ilona Rolfes ◽  
Daniel Erni ◽  
Thomas Kaiser ◽  
...  
Keyword(s):  
Signal Processing ◽  
Dielectric Materials ◽  
Sparse Signal ◽  
Sparse Signal Processing

Dielectric Characterization of Polyceram Films

1990 ◽  
Vol 180 ◽  
Author(s):  
G. Teowee ◽  
J.M. Boulton ◽  
H.H. Fox ◽  
A. Koussa ◽  
T. Gudgel ◽  
...  
Keyword(s):  
Dielectric Constant ◽  
Polyethylene Oxide ◽  
Dielectric Materials ◽  
Inorganic Materials ◽  
Functionalized Polymers ◽  
Multifunctional Materials ◽  
Dielectric Characterization ◽  
Silicon Alkoxides ◽  
Tan Δ

ABSTRACTPolycerams are an emergent class of hybrid, multifunctional materials which combine the properties of organic and inorganic materials. Films have been prepared from silicon alkoxides and reactive, functionalized polymers such as triethoxysilyl modified polybutadiene (MPBD), (N-triethoxysilylpropyl)O polyethylene oxide urethane (MPEOU) and trimethoxysilylpropyl substituted polyethyleneimine (MPEI). Characterization of dielectric constant and tan δ of the films has been carried out over a range of frequency from 500 Hz to 100 kHz; and the results are used to consider the potential of Polycerams as dielectric materials.

Performance Characterization of a Twin Scroll Volute for Turbocharging Applications

2018 ◽  
Author(s):  
Carlo Cravero ◽  
Mario La Rocca ◽  
Andrea Ottonello
Keyword(s):  
Experimental Data ◽  
Scientific Literature ◽  
Aerodynamic Performance ◽  
Operating Conditions ◽  
Automatic Design ◽  
Cfd Model ◽  
Radial Turbine ◽  
Wide Range ◽  
Partial Admission

The use of twin scroll volutes in radial turbine for turbocharging applications has several advantages over single passage volute related to the engine matching and to the overall compactness. Twin scroll volutes are of increasing interest in power unit development but the open scientific literature on their performance and modelling is still quite limited. In the present work the performance of a twin scroll volute for a turbocharger radial turbine are investigated in some detail in a wide range of operating conditions at both full and partial admission. A CFD model for the volute have been developed and preliminary validated against experimental data available for the radial turbine. Then the numerical model has been used to generate the database of solutions that have been investigated and used to extract the performance. Different parameters and indices are introduced to describe the volute aerodynamic performance in the wide range of operating conditions chosen. The above parameters can be used for volute development or matching with a given rotor or efficiently implemented in automatic design optimization strategies.

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