
	Where results make sense

Topic: Permittivity

Related Topics

Electrical elastance

Displacement current

Farad

Electrical conductivity

Coulomb

Magnetic permeability

Current (electricity)

Volt

Electric displacement field

Quantity of electricity

Electric charge

Dielectric constant

Crystal optics

Electromagnetism

Ohm

In the News (Mon 23 Nov 09)

Northern Trust

Marvin Harrison

Peter Chernin

Gary Locke

Match Play

Penelope Cruz

Mickey Rourke

AR Rahman

Danny Boyle

Hugh Jackman

	Permittivity - Wikipedia, the free encyclopedia
		Permittivity is a physical quantity that describes how an electric field affects and is affected by a dielectric medium and is determined by the ability of a material to polarize in response to an applied electric field, and thereby to cancel, partially, the field inside the material.
		In SI units, permittivity is measured in farads per metre (F/m).
		The complex permittivity is usually a complicated function of frequency ω, since it is a sumperimposed description of dispersion phenomena occurring at multiple frequencies.
	en.wikipedia.org /wiki/Permittivity (1708 words)

	Permittivity - (Site not responding. Last check: 2007-08-20)
		The permittivity of free space, $\varepsilon_0$ , is the scale factor that relates the values of D and E in a vacuum.
		The permittivity of a material is usually given relative to that of vacuum, as a relative permittivity, $\varepsilon_{r}$ (also called dielectric constant in some cases).
		The complex permittivity is usually a complicated function of frequency ω, since it is a sumperimposed description of dispersion phenomena occurring at multiple frequencies.
	psychcentral.com /psypsych/Permittivity (1884 words)

	Permittivity - Microwave Encyclopedia - Microwaves101.com
		In microwaves, we often refer to permittivity as the "dielectric constant", these terms a interchangeable, but "permittivity" sounds more scholarly if you want to pretend to be a nerd.
		Permittivity is what controls the value of a capacitor, beyond its physical dimensions.
		Permittivity measurements are easy to do, but it is hard to measure permittivity with great accuracy.
	www.microwaves101.com /encyclopedia/permittivity.cfm (411 words)

	[No title] (Site not responding. Last check: 2007-08-20)
		A still further object of this invention is to propose a process and apparatus for the measurement and monitoring of complex permittivity and conductivity of materials in situ and used for high frequency circuits boards, various bulk polymers and semiconductor materials.
		Yet a further object of this invention is to propose a process and apparatus for the measurement and monitoring of complex permittivity and conductivity of materials in situ and wherein transmission type resonators may be used for samples of smaller size than the resonator.
		The material under test, 4 for which complex permittivity, 6 is to be measured is kept in direct contact of the resonator or keeping a gap of few microns from the resonator.
	www.wipo.int /cgi-pct/guest/getbykey5?KEY=00/77501.001221&ELEMENT_SET=DECL (4717 words)

	Permittivity (Site not responding. Last check: 2007-08-20)
		Permittivity is the quality of a material that allows it to store an electrical charge.
		Permittivity is the time-space-mass domain expression of velocity^-2.
		James Maxwell (1831-1879) formulated the concepts of permittivity and permeability to serve as constants in his equations which described most electro-magnetic behavior.
	home.earthlink.net /~tdp/permittivity.html (146 words)

	[No title] (Site not responding. Last check: 2007-08-20)
		In the illustrated example, the permittivity characterization is made relative to the permittivity of a reference sample.
		The database may be made accessible via electronic means such as a local area network or the Internet to permit users to compare the permittivity values of their unknown samples with the known permittivity values of the database, thereby assisting the user in analyzing the molecular event makeup of their samples.
		The computed permittivity may be either an absolute value figure or made relative to a reference sample if the reflection coefficient is made relative to the reflection coefficient of a reference sample.
	www.wipo.int /cgi-pct/guest/getbykey5?KEY=02/65127.030410&ELEMENT_SET=DECL (11465 words)

	ARS \| Publication request: The Dielectric Permittivity of Calcitic and Arid Zone Soils with Carbonate Minerals
		The permittivity of air and water are well documented, however, the permittivity of soil minerals is often estimated and their permittivity essentially remains a fitting parameter in many models.
		Dielectric permittivity of the soil mineral phase, for modeling purposes, is assumed in most cases to be 5, a value based on a further assumption that soils are predominantly quartz.
		This study was conducted to measure the solid permittivity of 4 illitic soils to determine whether or not the assumption of 5 for the dielectric permittivity of arid zone soils is correct.
	www.ars.usda.gov /research/publications/publications.htm?SEQ_NO_115=155304 (512 words)

	Microwave Processing Laboratory for Advanced Materials
		The absorbed microwave in a material is determined by the imaginary part of the complex permittivity and the electric field.
		Since there is a lack of knowledge in the complex permittivity of ceramics with respect to temperature and density, it is difficult to model the sample power absorption, temperature distribution and densification.
		Complex permittivity measurements are performed by placing a flat side of a sufficiently thick sample onto the probe.
	www.ipr.umd.edu /MPL/tour.htm (756 words)

	Plasmons (Site not responding. Last check: 2007-08-20)
		At optical frequencies, the response of metals to electromagnetic fields depends on the illumination wavelength (this is not the case at lower frequencies, like in the microwave regime, where most metals can be considered as perfect conductors).
		This dependence is characterized by the permittivity of the metal, which varies with the frequency (or the wavelength), as illustrated in Fig.
		The variations of its permittivity as a function of the wavelength has a strong impact on the scattering properties of a given particle.
	www.ifh.ee.ethz.ch /~martin/res50.en.html (609 words)

	Permittivity
		The measurement of the Permittivity of fluids through porous media has generally been performed on a rather primitive level in comparison to related measurements: the flow of electricity and heat through conductors or diffusion of one material through another.
		In contrast, fluid Permittivity is often determined for a porous media sealed to the bottom of a pressurized fluid-filled reservoir.
		In response to these technological requirements, an Advanced Permittivity Testing Method has been devised, wherein fluid forces and fluxes are, separately and simultaneously, measured under controlled conditions, in accordance with phenomenological requirements, to determine the Permittivity of porous media.
	www.mc2link.com /permittivity (259 words)

	Considerations for Improving the Accuracy of Permittivity Measurement using Time Domain Reflectometry: Air-Water ...
		The permittivity of a water-filled coaxial cell was measured
		Permittivity estimated from calibration of probe adjusting the electrical length of the probe according to measurements in water using the bump apex as a timing reference.
		Permittivity calculated as a function of immersion length using a fixed start point and one following the bump apex.
	soil.scijournals.org /cgi/content/full/67/1/62 (5202 words)

	Calculation of the Dielectric Properties of Temperate and Tropical Soil Minerals from Ion Polarizabilities using the ...
		Measurements of the permittivity of the clay minerals are uncommon
		Calculated values of permittivity of dehydrated phyllosilicates based on the chemical formula and density data presented in Weast (1984) and McClune (1980).
		The effective permittivity of dense packing of glass beads, quartz sand and their mixtures immersed in different dielectric backgrounds.
	soil.scijournals.org /cgi/content/full/68/5/1780 (2994 words)

	Permittivity 5
		By means of the thrust shaft, the drive motor moves the pistons at a constant speed, forcing the fluid through the specimen fabric at a constant flow rate.
		The permittivity testing procedure is fully automated, as shown in Figure 5.3, using the electric valve for fluid control.
		To prevent collapse of the tube on piston motion reversal, the chambers are connected across the electric valve, as represented in Figure 5.5b.
	www.mc2link.com /permittivity/perm5.html (546 words)

	Permittivity (Site not responding. Last check: 2007-08-20)
		The permittivity of a substance is a characteristic which describes how it affects any electric field set up in it.
		We can increase the capacitance of a capacitor by increasing the permittivity of the dielectric material.
		The permittivity of a material is usually given relative to that of free space, it is known as relative permittivity
	schools.matter.org.uk /SchoolsGlossary/permittivity.html (82 words)

	Permittivity - Search Results - MSN Encarta
		Permittivity, the property of a material that determines the strength of the electric field produced by a distribution of electric charges.
		Dielectric properties are measured by relative permittivity (dielectric constant), which is related to the static charge on the surface when an...
		is the permittivity of free space, and ε
	uk.encarta.msn.com /Permittivity.html (98 words)

	Chapter 6. Permittivity Constant
		The reason for its existence is to prevent electronic equations from using SI units by forcing the use of the quantum attributes of the electron as units of measure and to express electronic force in terms of inertial force.
		It is simply the SI value that is necessary to convert the SI-based Coulomb proportion into an equation.
		This opens a whole new area of speculation as to its significance, which I pursue in the subjective and metaphysical Part Two.
	www.writword.com /unituniv/c06.htm (829 words)

	A method for measuring the solid particle permittivity or electrical conductivity of rocks, sediments, and granular ...
		The method requires the measurement of the effective permittivity of a granular material immersed in fluids of differing permittivity and interpolation between the range of data points.
		Measurements of the permittivity of the mineral matrix of a number of materials are presented, including glass beads (7.6), quartz sand (4.7), calcareous seashell fragments (8.9), hematite ore (18.1), tuff (6.0), and a sandy loam soil (5.1).
		Estimates based on using mixing models to obtain the solid permittivity are demonstrated to underestimate the permittivity of hematite ore by between 0% and 45%, depending on the model and packing.
	www.agu.org /pubs/crossref/2003/2001JB000691.shtml (348 words)

	Water dielectric and microwave radiation: Complex dielectric permittivity
		It has been suggested that a bimodal relaxation time expression is the most appropriate description of the dielectric properties of water [135].
		is the relative permittivity at low frequencies (static region), e
		is the relative permittivity at high frequencies (optical permittivity), w is the angular frequency in radians.second
	www.lsbu.ac.uk /water/microwav3.html (255 words)

	Define permittivity - a definition from Whatis.com
		Permittivity, also called electric permittivity, is a constant of proportionality that exists between electric displacement and
		In engineering applications, permittivity is often expressed in relative, rather than in absolute, terms.
		Dielectrics are used in capacitors and transmission lines in alternating current (AC), audio frequency (AF), and radio frequency (RF) applications.
	searchsmb.techtarget.com /sDefinition/0,,sid44_gci546287,00.html (215 words)

	Electric field
		One is the speed of light c, and the other two are the electric permittivity of free space
		In the case of a polarizable medium, called a dielectric, the comparison is stated as a relative permittivity or a dielectric constant.
		In the case of magnetic media, the relative permeability may be stated.
	hyperphysics.phy-astr.gsu.edu /hbase/electric/elefie.html (223 words)

	Coulomb's Law: Electrostatics: Plus 2 Physics (Site not responding. Last check: 2007-08-20)
		is an electrical property of the medium surrounding the two charges and it is called the permittivity of that medium.
		The ratio of the force in vacuum to the force in any other medium between the same pair of point charges separated by the same distance is called the relative permittivity of that medium
		Since vacuum has absolutely no charge carriers, the permittivity is the lowest for vacuum.
	www.plus2physics.com /electrostatics/study_material.asp (311 words)

	What is the significance of permittivity of free space?
		For most of our experiences we insist on measuring charge in coulombs and measuring forces (or electric fields) in Newtons (Newtons per coulomb).
		The coefficient that we need to make it come out right is related to the permittivity of free space.
		The words probably go back to the days when we thought there was an ether in space.
	www.newton.dep.anl.gov /newton/askasci/1993/physics/PHY48.HTM (175 words)

	FMI - Research - Space Research - Planetary research - Rosetta - Permittivity Probe
		Permittivity Probe (PP) is designed to measure the complex permittivity, i.e., electrical conductivity and dielectric polarizability, of the cometary nucleus at the landing site of the Rosetta Lander, down to a depth of a few meters.
		PP is an active instrument that measures the influence of a material upon the electrical coupling between two dipoles in contact with its surface.
		Sampling the total intensity of plasma waves every few second, these measurements will consequently provide a continuous monitoring of the nucleus activity.
	www.fmi.fi /research_space/space_34.html (305 words)

	ARS \| Publication request: Dimensional Analysis of a Permittivity Measurement Probe
		Interpretive Summary: Dielectric properties of materials are the characteristics of materials, which are relatively poor conductors of electricity, that determine how they interact with electromagnetic fields.
		The problem is reduced from fitting a model of two variables, frequency and permittivity, to one dimensionless variable.
		In addition the dimensional analysis also revealed that the same results hold for any permittivity measurement probe where the admittance of the probe is a function of permittivity, frequency, and any number of linear dimensions.
	www.ars.usda.gov /research/publications/Publications.htm?seq_no_115=136384 (416 words)

Try your search on: Qwika (all wikis)