In electromagnetism, a dielectric is an electrical insulator that can be polarised by an applied electric field. When a dielectric material is placed in an electric field, electric charges do not flow through the material as they do in an electrical conductor, because they have no loosely bound, or free, electrons that may drift through the material, but instead they shift, only slightly, from their average equilibrium positions, causing dielectric polarisation. Because of dielectric polarisation, positive charges are displaced in the direction of the field and negative charges shift in the direction opposite to the field. This creates an internal electric field that reduces the overall field within the dielectric itself. If a dielectric is composed of weakly bonded molecules, those molecules not only become polarised, but also reorient so that their symmetry axes align to the field.
In physics, the term dielectric strength has the following meanings:
Polyethylene or polythene (abbreviated PE; IUPAC name polyethene or poly(methylene)) is the most commonly produced plastic. It is a polymer, primarily used for packaging (plastic bags, plastic films, geomembranes and containers including bottles, etc.). As of 2017, over 100 million tonnes of polyethylene resins are being produced annually, accounting for 34% of the total plastics market.
Sulfur hexafluoride or sulphur hexafluoride (British spelling) is an inorganic compound with the formula SF6. It is a colorless, odorless, non-flammable, and non-toxic gas. SF
6 has an octahedral geometry, consisting of six fluorine atoms attached to a central sulfur atom. It is a hypervalent molecule.
A nanostructure is a structure of intermediate size between microscopic and molecular structures. Nanostructural detail is microstructure at nanoscale.
In electrical engineering, treeing is an electrical pre-breakdown phenomenon in solid insulation. It is a damaging process due to partial discharges and progresses through the stressed dielectric insulation, in a path resembling the branches of a tree. Treeing of solid high-voltage cable insulation is a common breakdown mechanism and source of electrical faults in underground power cables.
A ferroelectret, also known as a piezoelectret, is a thin film of polymer foams, exhibiting piezoelectric and pyroelectric properties after electric charging. Ferroelectret foams usually consist of a cellular polymer structure filled with air. Polymer-air composites are elastically soft due to their high air content as well as due to the size and shape of the polymer walls. Their elastically soft composite structure is one essential key for the working principle of ferroelectrets, besides the permanent trapping of electric charges inside the polymer voids. The elastic properties allow large deformations of the electrically charged voids. However, the composite structure can also possibly limit the stability and consequently the range of applications.
Electromanipulation is a micro-material analyzing method mostly used for manipulations of biological cells that uses properties of diverse electric fields. In nanotechnology, nanomaterials are so small that they can hardly be directly mechanically manipulated. Hence, electric fields are applied to them to make field-induced movements or deformations. It is a recently developed technology and is still in progress of widening applications. Types of Electronmanipulation includes dielectrophoresis, electro-rotation, electro-deformation, electro-disruption, electro-destruction, electroporation, and electro-fusion. Diverse electromanipulations are achieved using various electric fields including AC(alternating current), DC(direct current), and pulsed(deliver high-energy discharges at very short periods) electrical fields. Electromanipulation of cells permits diverse cell manipulations with minimal mechanical contact between cells and device structures. Although predominantly used in cells, elctromanipulation also contributes to other scientific fields such as Hybridoma technology and nanoelectronic devices development.
In microscopy, conductive atomic force microscopy (C-AFM) or current sensing atomic force microscopy (CS-AFM) is a mode in atomic force microscopy (AFM) that simultaneously measures the topography of a material and the electric current flow at the contact point of the tip with the surface of the sample. The topography is measured by detecting the deflection of the cantilever using an optical system, while the current is detected using a current-to-voltage preamplifier. The fact that the CAFM uses two different detection systems is a strong advantage compared to scanning tunneling microscopy (STM). Basically, in STM the topography picture is constructed based on the current flowing between the tip and the sample. Therefore, when a portion of a sample is scanned with an STM, it is not possible to discern if the current fluctuations are related to a change in the topography or to a change in the sample conductivity.
A severity factor is established as a coefficient to assess the dielectric severity supported by a transformer winding considering the incoming transient overvoltage. It determines the safety margin regarding to the standard acceptance tests either in the frequency or time domain.
Reimund Gerhard is a German applied physicist and university professor. Between 1979 and 2006 he used the last name "Gerhard-Multhaupt".
Antonio Castellanos Mata was a Spanish physicist.
Soft robotics is a subfield of robotics that concerns the design, control, and fabrication of robots composed of compliant materials, instead of rigid links. In contrast to rigid-bodied robots built from metals, ceramics and hard plastics, the compliance of soft robots can improve their safety when working in close contact with humans.
Hans Tropper (1905–1978) was an Austrian Professor of Electrical Engineering with research interest in breakdown strength of liquid insulation. The ‘Hans Tropper Memorial Lecture’ is held in his honour to open each IEEE International Conference on Dielectric Liquids. He also briefly worked for Elin Aktiengesellschaft fur Elektrische Industrie.
In physics and electrical engineering, the universal dielectric response, or UDR, refers to the observed emergent behaviour of the dielectric properties exhibited by diverse solid state systems. In particular this widely observed response involves power law scaling of dielectric properties with frequency under conditions of alternating current, AC. First defined in a landmark article by A. K. Jonscher in Nature published in 1977, the origins of the UDR were attributed to the dominance of many-body interactions in systems, and their analogous RC network equivalence.
Tetravinyltin (also known as tetravinylstannane) is an organotin compound with a chemical formula of C8H12Sn.
Diglycidyl resorcinol ether, also called Resorcinol diglycidyl ether (RDGE) is a liquid aromatic organic chemical compound and chemically a glycidyl ether.
Phenyl glycidyl ether, is a liquid aromatic organic chemical in the glycidyl ether class of compounds. It has the formula C9H10O2. It has the CAS Registry Number 122-60-1 and the IUPAC name of 2-(phenoxymethyl)oxirane. A key use is in the viscosity reduction of epoxy resin systems. It is REACH registered and on EINECS under the name 2,3-epoxypropyl phenyl ether.
C4-FN (C4-fluoronitrile, C4FN) is a perfluorinated compound developed as a high-dielectric gas for high-voltage switchgear. It has the structure (CF3)2CFC≡N, which can be described as perfluoroisobutyronitrile, falling under the category of PFAS, or per- and polyfluoroalkyl substances.
1,2-Dimorpholinoethane is an organic chemical and specifically a nitrogen-oxygen heterocyclic compound. At room temperature it is a solid with a melting point of 75 °C. It has two tertiary amines in the same molecule meaning it is ideal for use as a polyurethane catalyst. It has the CAS Registry Number 1723-94-0 and is TSCA and REACH registered and on EINECS with the number 217-026-5. The IUPAC name is 4-(2-morpholin-4-ylethyl)morpholine and the chemical formula C10H20N2O2.
