Electrical conductivity of metal plates is measured by two distinct methods and the uncertainty associated with each method evaluated. First, impedance an air-cored eddy-current coil in frequency range 100 Hz to 20 kHz. Corrections are made account for fact that not a pure inductor but exhibits finite resistance capacitance between windings. Then, brass stainless steel determined 3 2% (68% confidence level) seeking best fit (least-mean-square error) experimental measurements values...

Microwave-absorbing materials find application in telecommunications, microwave heating and for representing the behavior of biological tissue presence radiation. Commonly, such are formed using ferromagnetic filler particles rely on phenomenon resonance absorption microwaves. Dielectric loss at frequencies can be engineered through creating a phase lag, with respect to applied electric field, movement free charges composite metal-coated particles. These less dense and, therefore, more...

Aging mechanisms of two polymeric insulation materials that are used widely in nuclear power plant low-voltage cables; cross-linked polyethylene (XLPE) and ethylene propylene rubber/ethylene diene terpolymer (EPR/EPDM), reviewed. A summary various nondestructive methods suitable for evaluation cable is given. capacitive sensor capable making local measurements capacitance dissipation factor on polymers, potentially situ monitoring, introduced.Correlating values elongation-at-break, indenter...

Nanocomposites composed of diblock copolymer/ferroelectric nanoparticles were formed by selectively constraining ferroelectric (NPs) within copolymer nanodomains via judicious surface modification NPs. Ferroelectric barium titanate (BaTiO3) NPs with different sizes that are permanently capped polystyrene chains (i.e., PS-functionalized BaTiO3NPs) first synthesized exploiting amphiphilic unimolecular star-like poly(acrylic acid)-block-polystyrene (PAA-b-PS) copolymers as nanoreactors....

A concentric coplanar capacitive sensor is analyzed for the quantitative characterization of material properties multi-layered dielectrics. The output signal, transcapacitance C <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">T</sub> , related to thickness and dielectric constant each layer under test. Electrostatic Green's functions due point charges over different structures are derived utilizing Hankel transform given cylindrical symmetry...

The technique of measuring the voltage difference (potential drop) between two four electrodes a four-point probe, in order to determine conductivity or surface resistivity test piece, is well established direct-current (dc) quasi-dc regime. finds wide usage semiconductor industry for purpose semiconductors, and also measurement metals, particularly ferromagnetic metals which cannot be easily measured using eddy-current nondestructive evaluation (NDE). In these applications, piece deduced...

A microwave nondestructive evaluation (NDE) sensor operating in the X-band (8.2 to 12.4 GHz) for detecting thickness or permittivity changes one layer of multilayered dielectric structures is presented. In particular, detection defects form variations core a three-layer structure, such as an aircraft radome, targeted. Using efficient analytical model calculating resonant frequency rectangular patch covered with structures, effects varying geometric and electrical parameters on its...

Polystyrene-capped barium titanate (BaTiO3) nanoparticles with sizes of 11 nm and 27 were prepared using amphiphilic star-like diblock copolymer templates. The crystal structure evolution these over a wide temperature range (10–428 K) was investigated by powder X-ray diffraction. Rietveld refinement indicates that the abrupt structural transitions observed in micron-sized powders become broad as particle size is reduced to few tens nanometers. orthorhombic phase (Amm2) 10–388 K, coexisting...

Insulating materials filled with conducting particles permit tailoring of electrical, electromagnetic and thermal properties the resulting composite. When filler are small metallic, a dielectric relaxation due to interfacial polarization is commonly observed at optical or smaller wavelengths. Here, experimental results presented in which shifted microwave frequencies as result using metal-coated nano-scale coating thickness. The analysed context effective medium theory adapted for...

A capacitive sensor has been developed for measuring the permittivity of wire insulation materials. The consists interdigital electrodes deposited on a thin polyimide substrate that conforms to surface insulated or cable. test piece was modeled theoretically by assuming perfectly conducting cylindrical rod coated with two concentric dielectric layers. Constant potential difference V between assumed. method moments and Green's function solution Poisson equation were utilized determine charge...

SiO2 coated Fe3O4 submicrometer spherical particles (a conducting core/insulating shell configuration) are fabricated using a hydrothermal method and loaded at 10 20 vol % into bisphenol E cyanate ester matrix for synthesis of multifunctional composites. The dielectric constant the resulting composites is found to be enhanced over wide frequency temperature range while low loss tangent neat polymer largely preserved up 160 °C due insulating coating on individual conductive spheres. These...

Measurements of alternating current potential drop (ACPD) made at the surface a conductive plate can be used to determine, non-destructively, parameters such as its thickness, electrical conductivity and linear effective magnetic permeability. In order invert measured yield values for these parameters, theoretical model is needed. this work, closed form analytical expressions are derived ACPD between two voltage electrodes four-point probe. Alternating injected extracted by electrodes. The...

The case depth of induction-hardened steel rods has been determined using multi-frequency alternating current potential-drop measurements. Experimental results are analyzed a model which approximates the variation in material properties hardened rod by assuming that homogeneous core is surrounded case-hardened layer uniform thickness. measurements on an untreated used to estimate conductivity and permeability similar rods. implicit assumption parameters region unchanged hardening process....

The change in dielectric properties of wire insulation due to various degradation processes is significant for health management air- and spacecraft. Polytetrafluoroethylene (PTFE) ethylene-tetrafluoroethylene (ETFE) are two fluoropolymers which have been widely applied as wiring materials. This paper investigates the response PTFE ETFE thermal exposure up 96 hours at 340°C 160°C, respectively. initial were measured using a Novocontrol spectrometer over frequency range 1 Hz MHz function...

An arc-electrode capacitive sensor has been developed for quantitative characterization of permittivity cylindrical dielectric rods. The material property the test piece can be inversely determined from output capacitance based on a theoretical model. For modeling process, electrostatic Green's function due to point source exterior rod is derived. numerically calculated using method moments (MoM), in which integral equation set up function. Numerical calculations configuration optimization...