WorldWideScience

Sample records for organic electrical insulating

  1. Measurement of full-field deformation induced by a dc electrical field in organic insulator films

    Directory of Open Access Journals (Sweden)

    Boudou L.

    2010-06-01

    Full Text Available Digital image correlation method (DIC using the correlation coefficient curve-fitting for full-field surface deformation measurements of organic insulator films is investigated in this work. First the validation of the technique was undertaken. The computer-generated speckle images and the measurement of coefficient of thermal expansion (CTE of aluminium are used to evaluate the measurement accuracy of the technique. In a second part the technique is applied to measure the mechanical deformation induced by electrical field application to organic insulators. For that Poly(ethylene naphthalene 2,6-dicarboxylate (PEN thin films were subjected to DC voltage stress and DIC provides the full-field induced deformations of the test films. The obtained results show that the DIC is a practical and robust tool for better comprehension of mechanical behaviour of the organic insulator films under electrical stress.

  2. Effects of cryogenic reactor irradiation on organic insulators

    International Nuclear Information System (INIS)

    Kato, Teruo

    1995-01-01

    Insulators for the superconducting magnets of fusion reactor are classified as electrical and thermal insulators for which tough organic materials will be used. When the magnet is exposed by fast neutrons and gamma-rays from plasma in a fusion reactor, the fusion reactor systems will cause fatal damage by the degradation of insulators. Therefore, it is necessary to select materials resistant irradiation damage for use as insulators. Electrical and mechanical tests were carried out at 4.2 K without warmup after the reactor irradiation at 5 K. The effects of reactor irradiation at the dose of 10 7 Gy on epoxy resins (bisphenol-A), G-10 CR, VL-E 200 and G-11 CR caused large decreases in mechanical strength. Polyetheretherketone (PEEK), polyimide and phenol novolac resins, which were used to laminate reinforced plastics with glass-cloth against irradiation, showed good resistance. Effects of cryogenic reactor irradiation on several organic materials and epoxy laminate-reinforced plastics with glass-cloth and Kevlar-cloth were also discussed. (author)

  3. Electrical insulator requirements for mirror fusion reactors

    International Nuclear Information System (INIS)

    Condit, R.H.; Van Konynenburg, R.A.

    1977-01-01

    The requirements for mirror fusion electrical insulators are discussed. Insulators will be required at the neutral beam injectors, injector power supplies, direct converters, and superconducting magnets. Insulators placed at the neutral beam injectors will receive the greatest radiation exposure, 10 14 to 10 16 neutrons/m 2 .s and 0.3 to 3 Gy/s (10 5 to 10 6 R/h) of gamma rays, with shielding. Direct converter insulators may receive the highest temperature (up to 1300 0 K), but low voltage holding requirements. Insulators made from organic materials (e.g., plastics) for the magnet coils may be satisfactory. Immediate conductivity increases of all insulators result from gamma irradiation. With an upper limit to gamma flux exposures of 300 Gy/s in a minimally shielded region, the conductivity could reach 10 -6 S/m. Damage from neutron irradiation may not be serious during several years' exposure. Surface changes in ceramics at the neutral beam injector may be serious. The interior of the injector will contain atomic hydrogen, and sputtering may transfer material away from or onto the ceramic insulators. Unknown and potentially damaging interactions between irradiation, electric fields, temperature gradients, cycling of temperature, surface and joint reactions, sputtering, polarization, and electrotransport in the dielectrics are of concern. Materials research to deal with these problems is needed

  4. Electric fields and electrical insulation

    DEFF Research Database (Denmark)

    McAllister, Iain Wilson

    2002-01-01

    The adoption of a field-theoretical approach to problems arising in the framework of electrical insulation is discussed with reference to six main topics, which have been addressed over the last 30 years. These include uniform field electrodes, Green's differential equation, electrode surface...... roughness, induced charge, electrostatic probes, and partial discharge transients, together with several follow-on aspects. Each topic is introduced and thereafter the progress achieved through the use of a field-theoretical approach is reviewed. Because the topics cover a wide spectrum of conditions......, it is amply demonstrated that such an approach can lead to significant progress in many areas of electrical insulation....

  5. Electrical machining method of insulating ceramics

    International Nuclear Information System (INIS)

    Fukuzawa, Y.; Mohri, N.; Tani, T.

    1999-01-01

    This paper describes a new electrical discharge machining method for insulating ceramics using an assisting electrode with either a sinking electrical discharge machine or a wire electrical discharge machine. In this method, the metal sheet or mesh is attached to the ceramic surface as an assisting material for the discharge generation around the insulator surface. When the machining condition changes from the attached material to the workpiece, a cracked carbon layer is formed on the workpiece surface. As this layer has an electrical conductivity, electrical discharge occurs in working oil between the tool electrode and the surface of the workpiece. The carbon is formed from the working oil during this electrical discharge. Even after the material is machined, an electrical discharge occurs in the gap region between the tool electrode and the ceramic because an electrically conductive layer is generated continuously. Insulating ceramics can be machined by the electrical discharge machining method using the above mentioned surface modification phenomenon. In this paper the authors show a machined example demonstrating that the proposed method is available for machining a complex shape on insulating ceramics. Copyright (1999) AD-TECH - International Foundation for the Advancement of Technology Ltd

  6. Electrical insulators for the theta-pinch fusion reactor

    International Nuclear Information System (INIS)

    Clinard, F.W. Jr.

    1976-01-01

    The five major applications for electrical insulators in the Reference Theta Pinch Reactor are as follows: (1) first-wall insulator, (2) blanket intersegment insulator, (3) graphite encapsulating insulator, (4) implosion coil insulator, and (5) compression coil insulator. Insulator design proposals and some preliminary test results are given for each application

  7. Inducing magneto-electric response in topological insulator

    International Nuclear Information System (INIS)

    Zeng, Lunwu; Song, Runxia; Zeng, Jing

    2013-01-01

    Utilizing electric potential and magnetic scalar potential formulas, which contain zero-order Bessel functions of the first kind and the constitutive relations of topological insulators, we obtained the induced magnetic scalar potentials and induced magnetic monopole charges which are induced by a point charge in topological insulators. The results show that infinite image magnetic monopole charges are generated by a point electric charge. The magnitude of the induced magnetic monopole charges are determined not only by the point electric charge, but also by the material parameters. - Highlights: ► Electric potential and magnetic scalar potential which contain zero-order Bessel function of the first kind were derived. ► Boundary conditions of topological insulator were built. ► Induced monopole charges were worked out.

  8. Inducing magneto-electric response in topological insulator

    Energy Technology Data Exchange (ETDEWEB)

    Zeng, Lunwu, E-mail: 163.sin@163.com [Jiangsu Key Laboratory for Intelligent Agricultural Equipment, College of Engineering, Nanjing Agricultural University, Nanjing 210031 (China); Song, Runxia [Jiangsu Key Laboratory for Intelligent Agricultural Equipment, College of Engineering, Nanjing Agricultural University, Nanjing 210031 (China); Zeng, Jing [Faculty of Business and Economics, Macquarie University, NSW 2122 (Australia)

    2013-02-15

    Utilizing electric potential and magnetic scalar potential formulas, which contain zero-order Bessel functions of the first kind and the constitutive relations of topological insulators, we obtained the induced magnetic scalar potentials and induced magnetic monopole charges which are induced by a point charge in topological insulators. The results show that infinite image magnetic monopole charges are generated by a point electric charge. The magnitude of the induced magnetic monopole charges are determined not only by the point electric charge, but also by the material parameters. - Highlights: Black-Right-Pointing-Pointer Electric potential and magnetic scalar potential which contain zero-order Bessel function of the first kind were derived. Black-Right-Pointing-Pointer Boundary conditions of topological insulator were built. Black-Right-Pointing-Pointer Induced monopole charges were worked out.

  9. Magnetohydrodynamic flow in ducts with discontinuous electrical insulation

    International Nuclear Information System (INIS)

    Mistrangelo, C.; Bühler, L.

    2015-01-01

    Highlights: • Liquid metal MHD flows in ducts with flow channel inserts. • Study of the influence of local interruption of electrical insulation. • 3D numerical simulations. - Abstract: In liquid metal blankets the interaction of the moving breeder with the intense magnetic field that confines the fusion plasma results in significant modifications of the velocity distribution and increased pressure drop compared to hydrodynamic flows. Those changes are due to the occurrence of electromagnetic forces that slow down the core flow and which are balanced by large driving pressure heads. The resulting magnetohydrodynamic (MHD) pressure losses are proportional to the electric current density induced in the fluid and they can be reduced by electrically decoupling the wall from the liquid metal. For applications to dual coolant blankets it is foreseen to loosely insert electrically insulating liners into the ducts. In long channels the insulation could consist of a number of shorter inserts, which implies a possible local interruption of the insulation. Three dimensional numerical simulations have been performed to investigate MHD flows in electrically well-conducting channels with internal discontinuous insulating inserts. The local jump in the electric conductivity of the duct wall results in induced 3D electric currents and related electromagnetic forces yielding additional pressure losses and increased velocity in boundary layers parallel to the magnetic field.

  10. Parametric and non-parametric models for lifespan modeling of insulation systems in electrical machines

    OpenAIRE

    Salameh , Farah; Picot , Antoine; Chabert , Marie; Maussion , Pascal

    2017-01-01

    International audience; This paper describes an original statistical approach for the lifespan modeling of electric machine insulation materials. The presented models aim to study the effect of three main stress factors (voltage, frequency and temperature) and their interactions on the insulation lifespan. The proposed methodology is applied to two different insulation materials tested in partial discharge regime. Accelerated ageing tests are organized according to experimental optimization m...

  11. Organic insulator studies at Los Alamos

    International Nuclear Information System (INIS)

    Parkin, D.M.; Clinard, F.W.

    1981-01-01

    The effects of radiation on the structural and electrical properties of organic insulators to be used in superconducting magnets in fusion devices has been identified as a critical materials problem. These materials will be exposed to both γ-ray and neutron radiation. LANL has been asked by the OFE Materials Branch to look at the relationship between the effects of γ-ray and neutron radiation effects. Some thoughts on planning the program are outlined

  12. Ageing of insulation and diagnosis of electrical equipment through detection of partial discharge

    International Nuclear Information System (INIS)

    Lopez Vergara, T.; Velasco Bernal, C.

    1994-01-01

    Ageing in electrical equipment affects mainly its insulation system. Such ageing in the insulation system is determined by its organic nature, basically constituted by three families of materials: cellulose, resin and hydrocarbon. All of these are affected by high temperatures, which tend to produce a break in the molecular chains (if the temperatures are not too high) or carbonization and gasification of the material (if they are). The radiation absorbed by the insulating materials also destroys molecular chains, causing degradation of the material. The break of the molecular chains, especially in the polymer-based materials, fragments the material, mainly in areas subjected to mechanical forces and stresses. From the electrical point of view, fissures occurring the insulating material lead to a much lower dielectric strength in certain parts of the materials, which could produce partial discharge conditions. Therefore, the growth of partial discharges in electrical equipment items is frequently the consequences of ageing, and be used to evaluate their residual life. Empresarios Agrupados has developed a system to detect partial discharges which can be used while equipment is still in operation. The measurements taken with this system are sufficiently accurate and repetitive to be used in evaluating the condition of medium-voltage electrical equipment insulation. (Author)

  13. DOE Task Force meeting on Electrical Breakdown of Insulating Ceramics in a High Radiation Field

    International Nuclear Information System (INIS)

    Green, P.H.

    1991-08-01

    This volume contains the abstracts and presentation material from the Research Assistance Task Force Meeting ''Electrical Breakdown of Insulating Ceramics in a High-Radiation Field.'' The meeting was jointly sponsored by the Office of Basic Energy Sciences and the Office of Fusion Energy of the US Department of Energy in Vail, Colorado, May 28--June 1, 1991. The 26 participants represented expertise in fusion, radiation damage, electrical breakdown, ceramics, and semiconductor and electronic structures. These participants came from universities, industries, national laboratories, and government. The attendees represented eight nations. The Task Force meeting was organized in response to the recent discovery that a combination of temperature, electric field, and radiation for an extended period of time has an unexplained adverse effect in ceramics, termed radiation-enhanced electrical degradation (REED). REED occurs after an incubation period and continues to accelerate with irradiation until the ceramics can no longer be regarded as insulators. It appears that REED is irreversible and the ceramic insulators cannot be readily annealed or otherwise repaired for future services. This effect poses a serious threat for fusion reactors, which require electrical insulators in diagnostic devices, in radio frequency and neutral beam systems, and in magnetic assemblies. The problem of selecting suitable electrical insulating materials in thus far more serious than previously anticipated

  14. Electrical Insulation of 500-m High-Tc Superconducting Power Cable

    International Nuclear Information System (INIS)

    Takahashi, T; Ichikawa, M; Suzuki, H; Okamoto, T; Akita, S; Mukoyama, S; Yagi, M; Maruyama, S; Kimura, A

    2006-01-01

    Electrical insulation is one of the essential technologies for the electric power apparatus. Determination of testing voltages and design method of the electrical insulation layer are inextricably linked each other, and are critical to developing and realizing a cold dielectric (CD) type high-Tc superconducting (HTS) power cable. The authors had proposed the electrical insulation design method with concepts of partial discharge-free designs for ac voltage condition. This paper discusses the testing voltages for a 77 kV 1000 A HTS power cable with a length of 500 m, and describes results of various voltage withstand test. As a result, it is concluded that the proposed electrical insulation design method is appropriate for the HTS power cable

  15. Insulation co-ordination in high-voltage electric power systems

    CERN Document Server

    Diesendorf, W

    2015-01-01

    Insulation Co-ordination in High-Voltage Electric Power Systems deals with the methods of insulation needed in different circumstances. The book covers topics such as overvoltages and lightning surges; disruptive discharge and withstand voltages; self-restoring and non-self-restoring insulation; lightning overvoltages on transmission lines; and the attenuation and distortion of lightning surges. Also covered in the book are topics such as the switching surge designs of transmission lines, as well as the insulation coordination of high-voltage stations. The text is recommended for electrical en

  16. SAFETY ALERT: Electrical insulation defect on safety helmets

    CERN Multimedia

    HSE Unit

    2013-01-01

    Contrarily to the information provided until 31 May 2013, some “Euro Protection” safety helmets do not respect any of the requirements for electrical insulation.   This alert concerns the safety helmets identified under the following SCEM numbers: 50.43.30.050.4 white 50.43.30.060.2 yellow 50.43.30.070.0 blue This amounts up to several hundreds of helmets on the CERN site. People who need to wear an electrically insulated safety helmet for their activities, must from now on acquire a duly insulated item to be found on the CERN store under the following SCEM numbers: 50.43.30.210.6: Petzl Vertex ST Helmet (without vent) 50.43.30.300.1: IDRA Helmet with a visor for electrical work As for the people who do not need to wear an electrically insulated helmet for their activities, they can continue working with the aforementioned helmets. For your information, please take note of the maximum use limit of each helmet: “Euro Protection” Safety Helme...

  17. Recent Progress in Electrical Insulation Techniques for HTS Power Apparatus

    Science.gov (United States)

    Hayakawa, Naoki; Kojima, Hiroki; Hanai, Masahiro; Okubo, Hitoshi

    This paper describes the electrical insulation techniques at cryogenic temperatures, i.e. Cryodielectrics, for HTS power apparatus, e.g. HTS power transmission cables, transformers, fault current limiters and SMES. Breakdown and partial discharge characteristics are discussed for different electrical insulation configurations of LN2, sub-cooled LN2, solid, vacuum and their composite insulation systems. Dynamic and static insulation performances with and without taking account of quench in HTS materials are also introduced.

  18. Electrical breakdown studies with Mycalex insulators

    International Nuclear Information System (INIS)

    Waldron, W.; Greenway, W.; Eylon, S.; Henestroza, E.; Yu, S.

    2003-01-01

    Insulating materials such as alumina and glass-bonded mica (Mycalex) are used in accelerator systems for high voltage feedthroughs, structural supports, and barriers between high voltage insulating oil and the vacuum beam pipe in induction accelerator cells. Electric fields in the triple points should be minimized to prevent voltage breakdown. Mechanical stress can compromise seals and result in oil contamination of the insulator surface. We have tested various insulator cleaning procedures including ultrasonic cleaning with a variety of aqueous-based detergents, and manual scrubbing with various detergents. Water sheeting tests were used to determine the initial results of the cleaning methods. Ultimately, voltage breakdown tests will be used to quantify the benefits of these cleaning procedures

  19. Electrical insulator assembly with oxygen permeation barrier

    Science.gov (United States)

    Van Der Beck, Roland R.; Bond, James A.

    1994-01-01

    A high-voltage electrical insulator (21) for electrically insulating a thermoelectric module (17) in a spacecraft from a niobium-1% zirconium alloy wall (11) of a heat exchanger (13) filled with liquid lithium (16) while providing good thermal conductivity between the heat exchanger and the thermoelectric module. The insulator (21) has a single crystal alumina layer (SxAl.sub.2 O.sub.3, sapphire) with a niobium foil layer (32) bonded thereto on the surface of the alumina crystal (26) facing the heat exchanger wall (11), and a molybdenum layer (31) bonded to the niobium layer (32) to act as an oxygen permeation barrier to preclude the oxygen depleting effects of the lithium from causing undesirable niobium-aluminum intermetallic layers near the alumina-niobium interface.

  20. Electrical-Based Diagnostic Techniques for Assessing Insulation Condition in Aged Transformers

    Directory of Open Access Journals (Sweden)

    Issouf Fofana

    2016-08-01

    Full Text Available The condition of the internal cellulosic paper and oil insulation are of concern for the performance of power transformers. Over the years, a number of methods have been developed to diagnose and monitor the degradation/aging of the transformer internal insulation system. Some of this degradation/aging can be assessed from electrical responses. Currently there are a variety of electrical-based diagnostic techniques available for insulation condition monitoring of power transformers. In most cases, the electrical signals being monitored are due to mechanical or electric changes caused by physical changes in resistivity, inductance or capacitance, moisture, contamination or aging by-products in the insulation. This paper presents a description of commonly used and modern electrical-based diagnostic techniques along with their interpretation schemes.

  1. Insulation assembly for electric machine

    Science.gov (United States)

    Rhoads, Frederick W.; Titmuss, David F.; Parish, Harold; Campbell, John D.

    2013-10-15

    An insulation assembly is provided that includes a generally annularly-shaped main body and at least two spaced-apart fingers extending radially inwards from the main body. The spaced-apart fingers define a gap between the fingers. A slot liner may be inserted within the gap. The main body may include a plurality of circumferentially distributed segments. Each one of the plurality of segments may be operatively connected to another of the plurality of segments to form the continuous main body. The slot liner may be formed as a single extruded piece defining a plurality of cavities. A plurality of conductors (extendable from the stator assembly) may be axially inserted within a respective one of the plurality of cavities. The insulation assembly electrically isolates the conductors in the electric motor from the stator stack and from other conductors.

  2. Investigation of deterioration mechanism of electrical ceramic insulating materials under high temperature

    International Nuclear Information System (INIS)

    Mizutani, Yoshinobu; Ito, Tetsuo; Okamoto, Tatsuki; Kumazawa, Ryoji; Aizawa, Rie; Moriyama, Hideshige

    2000-01-01

    It is thought that ceramic insulator can be applied to electric power equipments that are under high temperature not to be able use organic materials. Our research has suggested components of mica-alumina combined insulation. As the results of and carried out temperature accelerating test, combined insulation life is expected long term over 40 years at over 500-Celsius degrees. However to construct high reliable insulating system, it is clarified deterioration mechanism on combined insulation and evaluates life of that. Therefore we carried out metal behavior test and voltage aging test using mica-sheet and alumina-cloth that are components of combined insulation under high temperature in nitrogen gas atmosphere. It is cleared two metal behavior mechanisms: One is that the opening of insulator are filled up with copper that is oxidized, the other is the metal diffuses in alumina-cloth through surface. And distance of metal behavior is able to be estimated at modulate temperature and in modulate time. It is also cleared that alumina-cloth is deteriorated by metal behavior into alumina-cloth. These results indicate that combined insulation is deteriorated from electrode side by metal behavior and is finally broken down through alumina-cloth. (author)

  3. Electrical insulation and conduction coating for fusion experimental devices

    International Nuclear Information System (INIS)

    Onozuka, Masanori; Tsujimura, Seiji; Toyoda, Masahiko; Inoue, Masahiko; Abe, Tetsuya; Murakami, Yoshio

    1996-01-01

    The development of electrical insulation and conduction coating methods that can be applied to large components of fusion experimental devices has been investigated. A thermal spraying method is used to coat the insulation or conduction materials on the structural components because of its applicability for large surfaces. The insulation material chosen was Al 2 O 3 , while Cr 3 C 2 -NiCr and WC-NiCr were chosen as conduction materials. These materials were coated on stainless steel substrates to examine the basic characteristics of the coated layers, such as their adhesive strength to the substrate, thermal shock resistance, electrical resistance, dielectric breakdown voltage, and thermal conductivity. It was found that they have sufficient electrical insulation and conduction properties, respectively. In addition, the sliding tests of the coated layers showed adequate frictional properties. The spraying method was tested on a 100- x 1000-mm surface and found to be applicable for large surfaces of experimental fusion devices. 9 refs., 6 figs., 15 tabs

  4. Improvements to the electrical insulation resistance of high quality magnesia insulated cables

    International Nuclear Information System (INIS)

    Mauger, R.A.; Goodings, A.

    1984-03-01

    Mineral insulated signal cables for nuclear reactor instrumentation schemes have to meet stringent electrical insulation requirements at high temperatures. This report discusses the factors which influence the attainment of this objective and the way in which it has been reached under industrial manufacturing conditions. It emphasises the importance of moisture and gives details of the improvements achieved as a result of moisture reduction. (author)

  5. The electric strength of high-voltage transformers insulation at effect of partial dischargers

    International Nuclear Information System (INIS)

    Khoshravan, E.; Zeraatparvar, A.; Gashimov, A.M.; Mehdizadeh, R.N.

    2001-01-01

    Full text : In paper the change of electric strength of high-voltage transformers insulation at the effect of partial discharges with space charge accumulation was investigated. It is revealed that the effect of partial discharges of insulation materials results the reduction of their pulsing electric strength which can restore the own initial value at releasing of saved charge the volume of a material under condition of absence the ineversible structural changes in it. Researches of high-voltage transformers insulation's non-failure operation conditions show, that at increasing of insulation work time in a strong electrical field the reduction of average breakdown voltages with simultaneous increasing of spread in discharge voltage values takes place. It authentically testifies to reduction of short-time discharge voltage of insulation materials during their electrical aging. As the basic reason of insulation electrical aging the partial discharges occurring in gas cavities inside insulation were considered. It is known that the space charges will be formed in insulation elements of high-voltage devices which effects in dielectrical property of these elements including the electric strength and the space charge formation can occur also at partial discharges in an alternating voltage while the service of high-voltage transformers. In the given work the experiments in revealing separate influence partial discharges in pulsing electric strength of insulation materials at presence and at absence inside them the space charge were spent

  6. Inkjet-Printed Organic Transistors Based on Organic Semiconductor/Insulating Polymer Blends.

    Science.gov (United States)

    Kwon, Yoon-Jung; Park, Yeong Don; Lee, Wi Hyoung

    2016-08-02

    Recent advances in inkjet-printed organic field-effect transistors (OFETs) based on organic semiconductor/insulating polymer blends are reviewed in this article. Organic semiconductor/insulating polymer blends are attractive ink candidates for enhancing the jetting properties, inducing uniform film morphologies, and/or controlling crystallization behaviors of organic semiconductors. Representative studies using soluble acene/insulating polymer blends as an inkjet-printed active layer in OFETs are introduced with special attention paid to the phase separation characteristics of such blended films. In addition, inkjet-printed semiconducting/insulating polymer blends for fabricating high performance printed OFETs are reviewed.

  7. Inkjet-Printed Organic Transistors Based on Organic Semiconductor/Insulating Polymer Blends

    Science.gov (United States)

    Kwon, Yoon-Jung; Park, Yeong Don; Lee, Wi Hyoung

    2016-01-01

    Recent advances in inkjet-printed organic field-effect transistors (OFETs) based on organic semiconductor/insulating polymer blends are reviewed in this article. Organic semiconductor/insulating polymer blends are attractive ink candidates for enhancing the jetting properties, inducing uniform film morphologies, and/or controlling crystallization behaviors of organic semiconductors. Representative studies using soluble acene/insulating polymer blends as an inkjet-printed active layer in OFETs are introduced with special attention paid to the phase separation characteristics of such blended films. In addition, inkjet-printed semiconducting/insulating polymer blends for fabricating high performance printed OFETs are reviewed. PMID:28773772

  8. Insulated Solar Electric Cooking – Tomorrow's healthy affordable stoves?

    Directory of Open Access Journals (Sweden)

    T. Watkins

    Full Text Available We present a cooking technology consisting of a solar panel directly connected to an electric heater inside of a well-insulated chamber. Assuming continued decrease in solar panel prices, we anticipate that in a few decades Solar Electric Cooking (SEC technologies will be the most common cooking technology for the poor. Appropriate use of insulation reduces the power demand making low-power Insulated Solar Electric Cooking (ISEC systems already cost competitive. We present a $100 prototype and preliminary results of two implementations in Uganda.

  9. Electrical insulation and conduction coating for fusion experimental devices

    Energy Technology Data Exchange (ETDEWEB)

    Onozuka, Masanori; Tsujimura, Seiji; Toyoda, Masahiko; Inoue, Masahiko [Mitsubishi Heavy Industries, Ltd., Yokohama (Japan); Abe, Tetsuya; Murakami, Yoshio [Japan Atomic Energy Research Inst., Naka (Japan)

    1996-01-01

    The development of electrical insulation and conduction coating methods that can be applied to large components of fusion experimental devices has been investigated. A thermal spraying method is used to coat the insulation or conduction materials on the structural components because of its applicability for large surfaces. The insulation material chosen was Al{sub 2}O{sub 3}, while Cr{sub 3}C{sub 2}-NiCr and WC-NiCr were chosen as conduction materials. These materials were coated on stainless steel substrates to examine the basic characteristics of the coated layers, such as their adhesive strength to the substrate, thermal shock resistance, electrical resistance, dielectric breakdown voltage, and thermal conductivity. It was found that they have sufficient electrical insulation and conduction properties, respectively. In addition, the sliding tests of the coated layers showed adequate frictional properties. The spraying method was tested on a 100- x 1000-mm surface and found to be applicable for large surfaces of experimental fusion devices. 9 refs., 6 figs., 15 tabs.

  10. Industrial manufacturing of electric insulators; Fabricacion industrial de aisladores electricos

    Energy Technology Data Exchange (ETDEWEB)

    Gonzalez, Lucia [Instituto de Investigaciones Electricas, Cuernavaca (Mexico)

    1988-12-31

    Porcelain is the insulating material more extensively used for electric insulators manufacturing, due to its dielectric properties; nevertheless, it presents fragility problems of manufacture and of resistance to the thermal shock, among others. For this reason studies are being conducted for the substitution of porcelain in the electric insulators manufacturing. In this area, the Instituto de Investigaciones Electricas developed an improved insulating formulation - the polymeric concrete- and an industrial prototype machine for the manufacture of high voltage electric insulators for outdoors use. [Espanol] La porcelana es el material aislante electrico mas utilizado en la elaboracion de aisladores electricos, debido a sus propiedades dielectricas; sin embargo, presenta problemas de fragilidad, de fabricacion y de baja resistencia al choque termico, entre otros. Es por ello que se realizan estudios para sustituir la porcelana en la fabricacion de aisladores electricos. En este campo, el Instituto de Investigaciones Electricas desarrollo una formulacion aislante mejorada -el concreto polimerico- y una maquina prototipo industrial para fabricar aisladores electricos de alto voltaje para uso en exteriores.

  11. Industrial manufacturing of electric insulators; Fabricacion industrial de aisladores electricos

    Energy Technology Data Exchange (ETDEWEB)

    Gonzalez, Lucia [Instituto de Investigaciones Electricas, Cuernavaca (Mexico)

    1987-12-31

    Porcelain is the insulating material more extensively used for electric insulators manufacturing, due to its dielectric properties; nevertheless, it presents fragility problems of manufacture and of resistance to the thermal shock, among others. For this reason studies are being conducted for the substitution of porcelain in the electric insulators manufacturing. In this area, the Instituto de Investigaciones Electricas developed an improved insulating formulation - the polymeric concrete- and an industrial prototype machine for the manufacture of high voltage electric insulators for outdoors use. [Espanol] La porcelana es el material aislante electrico mas utilizado en la elaboracion de aisladores electricos, debido a sus propiedades dielectricas; sin embargo, presenta problemas de fragilidad, de fabricacion y de baja resistencia al choque termico, entre otros. Es por ello que se realizan estudios para sustituir la porcelana en la fabricacion de aisladores electricos. En este campo, el Instituto de Investigaciones Electricas desarrollo una formulacion aislante mejorada -el concreto polimerico- y una maquina prototipo industrial para fabricar aisladores electricos de alto voltaje para uso en exteriores.

  12. Electrical actuation of electrically conducting and insulating droplets using ac and dc voltages

    International Nuclear Information System (INIS)

    Kumari, N; Bahadur, V; Garimella, S V

    2008-01-01

    Electrical actuation of liquid droplets at the microscale offers promising applications in the fields of microfluidics and lab-on-chip devices. Much prior research has targeted the electrical actuation of electrically conducting liquid droplets using dc voltages (classical electrowetting). Electrical actuation of conducting droplets using ac voltages and the actuation of insulating droplets (using dc or ac voltages) has remained relatively unexplored. This paper utilizes an energy-minimization-based analytical framework to study the electrical actuation of a liquid droplet (electrically conducting or insulating) under ac actuation. It is shown that the electromechanical regimes of classical electrowetting, electrowetting under ac actuation and insulating droplet actuation can be extracted from the generic electromechanical actuation framework, depending on the electrical properties of the droplet, the underlying dielectric layer and the frequency of the actuation voltage. This paper also presents experiments which quantify the influence of the ac frequency and the electrical properties of the droplet on its velocity under electrical actuation. The velocities of droplets moving between two parallel plates under ac actuation are experimentally measured; these velocities are then related to the actuation force on the droplet which is predicted by the electromechanical model developed in this work. It is seen that the droplet velocities are strongly dependent on the frequency of the ac actuation voltage; the cut-off ac frequency, above which the droplet fails to actuate, is experimentally determined and related to the electrical conductivity of the liquid. This paper then analyzes and directly compares the various electromechanical regimes for the actuation of droplets in microfluidic applications

  13. Epoxy/α-alumina nanocomposite with high electrical insulation performance

    Directory of Open Access Journals (Sweden)

    Yun Chen

    2017-10-01

    Full Text Available An experimental study was conducted to improve the electrical insulation of epoxy resin. The effects of boehmite, γ-alumina and α-alumina nanoparticles on the volume resistivity, dielectric strength and glass transition temperature of epoxy nanocomposites were investigated. The results showed that α-alumina nanoparticles displayed obvious advantages in enhancing electrical insulation performance of epoxy nanocomposites, compared to boehmite and γ-alumina nanoparticles. The direct current volume resistivity and breakdown strength of epoxy nanocomposite with 2.0 wt% α-alumina nanoparticles was improved to 2.2 × 1018 Ω cm and 76.1 kV mm−1 respectively. And these improved values of electrical insulation properties are much higher than these of epoxy nanocomposites reported in previous studies. The main reason of these improvements may be that the epoxy/α-alumina interaction zone was enhanced by crosslink. Keywords: Nanocomposite, Epoxy resin, Insulation, α-alumina

  14. Microscopic Void Detection for Predicting Remaining Life in Electric Cable Insulation

    International Nuclear Information System (INIS)

    Horvath, David A.; Avila, Steven M.

    2003-01-01

    A reliable method of testing for remaining life in electric cable insulation has continued to elude the nuclear industry as it seeks to extend the life and license of its nuclear stations. Until recently, a trendable, measurable electrical property has not been found, and unexpected cable failures continue to be reported. Most reliable approaches to date rely on monitoring mechanical properties, which are assumed to degrade faster than the insulation's electrical properties. This paper introduces a promising technique based on void characterization, which is dependent on an electrical property related to dielectric strength. A relationship between insulation void characteristics (size and density) and the onset of partial discharge is known to exist. A similar relationship can be shown between void characteristics and unacceptable leakage currents (another typical cable failure criterion). For low-voltage cables, it is believed void content can be correlated to mechanical property degradation.This paper will report on an approach for using void information, research results showing the existence of trendable void characteristics in commonly used electric insulation materials, and techniques for detecting the voids (both laboratory- and field-based techniques). Acoustical microscopy was found to be potentially more suitable than conventional ultrasound for nondestructive in situ detection and monitoring of void characteristics in jacketed multiconductor insulation while ignoring the jacket. Also, optical and scanning electron microscope techniques will play an essential role in establishing the database necessary for continued development and implementation of this promising technique

  15. Development of electrical insulator coatings for fusion power applications

    International Nuclear Information System (INIS)

    Park, J.H.; Domenico, T.; Dragel, G.; Clark, R.

    1995-01-01

    In the design of liquid-metal cooling systems for fusion blanket applications, the corrosion resistance of structural materials and the magnetohydrodynamic (MHD) force and its subsequent influence on thermal hydraulics and corrosion are major concerns. The objective of this study was to develop stable corrosion-resistant electrical insulator coatings at the liquid-metal-structural-material interface, with emphasis on electrically insulating coatings that prevent adverse MHD-generated currents from passing through the structural walls. Vanadium and V-base alloys (V-Ti or V-Ti-Cr) are leading candidate materials for structural applications in fusion reactors. When the system is cooled by liquid metals, insulator coatings are required on piping surfaces in contact with the coolant. Various intermetallic films were produced on V, V-5Ti, and V-20Ti, V-5Cr-5Ti, and V-15Cr-5Ti, and Ti, and on types 304 and 316 stainless steel. The intermetallic layers were developed by exposure of the materials to liquid Li containing 3-5at.% dissolved metallic solute (e.g. Al, Be, Mg, Si, Ca, Pt, and Cr) at temperatures of 416-880 C. Subsequently, electrical insulator coatings were produced by reaction of the reactive layers with dissolved N in liquid Li or by air oxidation under controlled conditions at 600-1000 C. These reactions converted the intermetallic layers to electrically insulating oxide-nitride or oxynitride layers. This coating method is applicable to reactor components. The liquid metal can be used over and over because only the solutes are consumed within the liquid metal. The technique can be applied to various shapes (e.g. inside or outside of tubes, complex geometrical shapes) because the coating is formed by liquid-phase reaction. This paper discusses initial results on the nature of the coatings (composition, thickness, adhesion, surface coverage) and their in situ electrical resistivity characteristics in liquid Li at high temperatures. (orig.)

  16. Development of electrical insulation and conduction coating for fusion experimental devices

    Energy Technology Data Exchange (ETDEWEB)

    Onozuka, M. [Mitsubishi Heavy Industries Ltd., Yokohama (Japan); Tsujimura, S. [Mitsubishi Heavy Industries Ltd., Yokohama (Japan); Toyoda, M. [Mitsubishi Heavy Industries Ltd., Yokohama (Japan); Inoue, M. [Mitsubishi Heavy Industries Ltd., Yokohama (Japan); Abe, T. [Japan Atomic Energy Research Inst., Naka (Japan); Murakami, Y. [Japan Atomic Energy Research Inst., Naka (Japan)

    1995-12-31

    Development of electrical insulation and conduction methods that can be applied for large components have been investigated for future large fusion experimental devices. A thermal spraying method is employed to coat the insulation or conduction materials on the structural components. Al{sub 2}O{sub 3} has been selected as an insulation material, while Cr{sub 3}C{sub 2}-NiCr and WC-NiCr have been chosen as conduction materials. These materials were coated on stainless steel base plates to examine the basic characteristics of the coated layers, such as their adhesive strength to the base plate and electrical resistance. It was found that they have sufficient electrical insulation and conduction properties, respectively. In addition, the sliding tests of the coated layers showed sufficient frictional properties. The applicability of the spraying method was examined on a 100mm x 1000mm surface and found to be applicable for large surfaces in fusion experimental devices. (orig.).

  17. Development of electrical insulation and conduction coating for fusion experimental devices

    International Nuclear Information System (INIS)

    Onozuka, M.; Tsujimura, S.; Toyoda, M.; Inoue, M.; Abe, T.; Murakami, Y.

    1995-01-01

    Development of electrical insulation and conduction methods that can be applied for large components have been investigated for future large fusion experimental devices. A thermal spraying method is employed to coat the insulation or conduction materials on the structural components. Al 2 O 3 has been selected as an insulation material, while Cr 3 C 2 -NiCr and WC-NiCr have been chosen as conduction materials. These materials were coated on stainless steel base plates to examine the basic characteristics of the coated layers, such as their adhesive strength to the base plate and electrical resistance. It was found that they have sufficient electrical insulation and conduction properties, respectively. In addition, the sliding tests of the coated layers showed sufficient frictional properties. The applicability of the spraying method was examined on a 100mm x 1000mm surface and found to be applicable for large surfaces in fusion experimental devices. (orig.)

  18. Solvothermal synthesis and electrical conductivity model for the zinc oxide-insulated oil nanofluid

    International Nuclear Information System (INIS)

    Shen, L.P.; Wang, H.; Dong, M.; Ma, Z.C.; Wang, H.B.

    2012-01-01

    A new kind of nanofluid, ZnO-insulated oil nanofluid was prepared from ZnO nanoparticles synthesized by solvothermal method. Electrical property measurement shows that the electrical conductivity increases by 973 times after adding 0.75% volumetric fraction of ZnO nanoparticles into the insulated oil. A linear dependence of the electrical conductivity on the volumetric fraction has been observed, while the temperature dependence of the electrical conductivity reveals a nonlinear relationship. An electrical conductivity model is established for the nanofluid by considering both the Brownian motion and electrophoresis of the ZnO nanoparticles. -- Highlights: ► Stable ZnO-insulated oil nanofluid was successfully prepared. ► The electrical conductivity of the ZnO nanofluid is investigated. ► A new model is established to explain the electrical properties of the nanofluid.

  19. The electrical characteristics of solid insulators for 154 kV class HTS transformer

    International Nuclear Information System (INIS)

    Cheon, H.G.; Choi, J.H.; Pang, M.S.; Kim, W.J.; Kim, S.H.

    2011-01-01

    HTS transformer, without any loss of insulation lifetime due to the reduction in terms of size and weight, can increase the overload capacity, and have some benefits such as the improvement in efficiency, minimization of environmental pollution, and convenient spatial arrangement, which contribute a lot to electric power system operation. However, for practical insulation design of the HTS transformer, it is necessary to establish the research on electrical properties LN 2 as well as solid insulators. These solid insulators have been used as main insulations for HTS transformer. In this paper, we discussed breakdown and V-t characteristics of glass fiber reinforced plastics (GFRP) and pressboard in LN 2 .

  20. Trial fabrication and preliminary characterization of electrical insulator for liquid metal system

    International Nuclear Information System (INIS)

    Nakamichi, Masaru; Kawamura, Hiroshi; Oyamada, Rokuro

    1995-03-01

    In the design of the liquid metal blanket, MHD pressure drop is one of critical issues. Ceramic coating on the surface of structural material is considered as an electrical insulator to reduce the MHD pressure drop. Ceramic coating such as Y 2 O 3 is a promising electrical insulator due to its high electrical resistivity and good compatibility with liquid lithium. This report describes the trial fabrication and preliminary characterization of electrical insulator for a design study of the liquid metal system. From the results of trial fabrication and preliminary characterization, it is concluded that densified atmospheric plasma spray Y 2 O 3 coating with 410SS undercoating between 316SS substrate and Y 2 O 3 coating is suitable for Y 2 O 3 coating fabrication. (author)

  1. A real-time insulation detection method for battery packs used in electric vehicles

    Science.gov (United States)

    Tian, Jiaqiang; Wang, Yujie; Yang, Duo; Zhang, Xu; Chen, Zonghai

    2018-05-01

    Due to the energy crisis and environmental pollution, electric vehicles have become more and more popular. Compared to traditional fuel vehicles, the electric vehicles are integrated with more high-voltage components, which have potential security risks of insulation. The insulation resistance between the chassis and the direct current bus of the battery pack is easily affected by factors such as temperature, humidity and vibration. In order to ensure the safe and reliable operation of the electric vehicles, it is necessary to detect the insulation resistance of the battery pack. This paper proposes an insulation detection scheme based on low-frequency signal injection method. Considering the insulation detector which can be easily affected by noises, the algorithm based on Kalman filter is proposed. Moreover, the battery pack is always in the states of charging and discharging during driving, which will lead to frequent changes in the voltage of the battery pack and affect the estimation accuracy of insulation detector. Therefore the recursive least squares algorithm is adopted to solve the problem that the detection results of insulation detector mutate with the voltage of the battery pack. The performance of the proposed method is verified by dynamic and static experiments.

  2. A percolation approach to study the high electric field effect on electrical conductivity of insulating polymer

    Science.gov (United States)

    Benallou, Amina; Hadri, Baghdad; Martinez-Vega, Juan; El Islam Boukortt, Nour

    2018-04-01

    The effect of percolation threshold on the behaviour of electrical conductivity at high electric field of insulating polymers has been briefly investigated in literature. Sometimes the dead ends links are not taken into account in the study of the electric field effect on the electrical properties. In this work, we present a theoretical framework and Monte Carlo simulation of the behaviour of the electric conductivity at high electric field based on the percolation theory using the traps energies levels which are distributed according to distribution law (uniform, Gaussian, and power-law). When a solid insulating material is subjected to a high electric field, and during trapping mechanism the dead ends of traps affect with decreasing the electric conductivity according to the traps energies levels, the correlation length of the clusters, the length of the dead ends, and the concentration of the accessible positions for the electrons. A reasonably good agreement is obtained between simulation results and the theoretical framework.

  3. A Review of Irradiation Effects on Organic-Matrix Insulation

    International Nuclear Information System (INIS)

    Simon, N.J.

    1993-01-01

    This review assesses the data base on epoxy and polyimide matrix insulation to determine whether organic electric insulation systems can be used in the toroidal field (TF) magnets of next generation fusion devices such as ITER* and TPX*. Owing to the difficulties of testing insulation under fusion reactor conditions, there is a considerable mismatch between the ITER requirements and the data that are currently available. For example, nearly all of the high-dose (5 x 10 7 to 10 8 Gy) data obtained on epoxy and polyimide matrix insulation employed gamma irradiation, electron irradiation, or reactor irradiation with a fast neutron fluence far below 10 23 /m 2 , the fluence expected for the insulation at the TF magnets, as set forth in ITER conceptual design documents. Also, the neutron spectrum did not contain a very high energy (E (ge) 5 MeV) component. Such data underestimate the actual damage that would be obtained with the neutron fluence and spectrum expected at a TF magnet. Experiments on a polyimide (Kapton) indicate that gamma or electron doses or mixed gamma and neutron reactor doses would have to be downgraded by a factor of up to ten to simulate fusion neutron doses. Even when neutrons did constitute a significant portion of the total dose, B-containing E-glass reinforcement was often used; therefore, excess damage from the 10 B + n → 7 Li + α reaction occurred near the glass-epoxy interface. This problem can easily be avoided by substituting B-free glass (R, S, or T types)

  4. Magnetically insulated fission electric cells for direct energy conversion

    International Nuclear Information System (INIS)

    Slutz, S.A.; Seidel, D.B.; Lipinski, R.J.; Rochau, G.E.; Brown, L.C.

    2003-01-01

    The principles of fission electric cells are reviewed. A detailed Monte Carlo model of the efficiency of a fission electric cell is presented and a theory of magnetically insulated fission electric cells (MIFECs) is developed. It is shown that the low operating voltages observed in previous MIFEC experiments were due to nonoptimal magnetic field profiles. Improved magnetic field profiles are presented. It is further shown that the large electric field present in a MIFEC limits the structure of the cathode and can lead to a displacement instability of the cathode toward the anode. This instability places constraints on the number of cells that can be strung together without some external cathode support. The large electric field stress also leads to electrical surface breakdown of the cathode. It is shown that this leads to the formation of a virtual cathode resulting in geometry constraints for spherical cells. Finally it is shown that the requirements of magnetic insulation and high efficiency leads to very low average density of the fissile material. Thus a reactor using fission electric cells for efficient direct energy conversion will be large and require a very large number of cells. This could be mitigated somewhat by the use of exotic fuels

  5. Methods for the improvement of electrical insulation in vacuum in the presence of transverse magnetic field

    International Nuclear Information System (INIS)

    Hara, Masanori; Suehiro, Junya; Shigematsu, Hidetaka; Yano, Shinsuke

    1989-01-01

    At present in electrical energy field, aiming at the development and operation of new energy sources for the future, the research on nuclear fusion reactors, MHD electricity generation, and electromagnetic energy storage is in progress, and in ordeer to form strong magnetic fields over wide space, large superconducting magnets are expected to be employed. In these magnets, when exciting current changes, voltage is induced internally, therefore, the operation sequence is deeply related to coil insulation, in pulse operation, coil insulation is one of the important factors determining the rating, and the withstand voltage design against the abnormal voltage at the time of quenching is related to the protection of coils. Therefore, the electrical insulation design of large superconducting magnets is an important subject of study. Their electrical insulation system is the compound system of liquid helium, gaseous helium, vacuum and solid insulators. When a cross magnetic field is applied, insulation breakdown characteristics are aggravated. The mechanism of vacuum insulation breakdown and characteristics, the method of improving withstand voltage using spacers or the electrodes for controlling electric field and so on are reported. (K.I.)

  6. High voltage diagnostics on electrical insulation of supersonducting magnets

    International Nuclear Information System (INIS)

    Irmisch, M.

    1995-12-01

    The high voltage (HV) performance of superconducting magnets of large dimensions, e.g. as needed in fusion reactors, is a challange in the field of high voltage technology, i.e. especially in the field of cryogenic high voltage components and with respect to questions of HV insulation diagnostics at low temperature. By using the development of POLO - a superconducting prototype coil of a tokamak poloidal field coil - as an example, this work deals with special problems of how to get use of conventional HV test techniques for diagnostics under special cryogenic boundary conditions. As a first approach to gain experience in the field of phase resolved partial discharge (PRPD) measurements during operation of a superconductive coil, the POLO coil was subject to several high voltage tests. Compared with DC insulation resistance measurements and capacitive impulse voltage discharges to the coil, the AC PD measurements have been the only way to observe special characteristics of the electrical insulation with respect to the cooling down of the coil from 300 K to 4.2 K. The PRPD measurement technique thereby has proofed as a suitable diagnostic tool. This work can serve as basic data to be comparable within further projects of electrical insulation diagnostics at cryogenic temperatures. (orig.)

  7. Transfer-free electrical insulation of epitaxial graphene from its metal substrate.

    Science.gov (United States)

    Lizzit, Silvano; Larciprete, Rosanna; Lacovig, Paolo; Dalmiglio, Matteo; Orlando, Fabrizio; Baraldi, Alessandro; Gammelgaard, Lauge; Barreto, Lucas; Bianchi, Marco; Perkins, Edward; Hofmann, Philip

    2012-09-12

    High-quality, large-area epitaxial graphene can be grown on metal surfaces, but its transport properties cannot be exploited because the electrical conduction is dominated by the substrate. Here we insulate epitaxial graphene on Ru(0001) by a stepwise intercalation of silicon and oxygen, and the eventual formation of a SiO(2) layer between the graphene and the metal. We follow the reaction steps by X-ray photoemission spectroscopy and demonstrate the electrical insulation using a nanoscale multipoint probe technique.

  8. Transfer-Free Electrical Insulation of Epitaxial Graphene from its Metal Substrate

    DEFF Research Database (Denmark)

    Lizzit, Silvano; Larciprete, Rosanna; Lacovig, Paolo

    2012-01-01

    High-quality, large-area epitaxial graphene can be grown on metal surfaces, but its transport properties cannot be exploited because the electrical conduction is dominated by the substrate. Here we insulate epitaxial graphene on Ru(0001) by a stepwise intercalation of silicon and oxygen......, and the eventual formation of a SiO2 layer between the graphene and the metal. We follow the reaction steps by X-ray photoemission spectroscopy and demonstrate the electrical insulation using a nanoscale multipoint probe technique....

  9. Effects of radiation at 5 K on organic insulators for superconducting magnets

    International Nuclear Information System (INIS)

    Coltman, R.R. Jr.; Klabunde, C.E.; Kernohan, R.H.; Long, C.J.

    1979-10-01

    Recent studies of the effects of irradiation at 5 K on organic insulators for fusion reactors have extended the irradiation dose from 2 x 10 9 to 1 x 10 10 rads and have looked for changes due to fast neutrons. For radiation conditions in this experiment the latter had little effect upon electrical and mechanical properties. At a dose of 1 x 10 10 rads, particle-filled epoxies are at ''end of life'' in terms of mechanical strength, while fiberglass-cloth-filled epoxies retain sufficient strength for use. Electrical-resistivity and voltage-breakdown vaues are reduced in some materials but remain in a usable range. Two sheet-type materials show excellent stability in their electrical properties

  10. The effects of fillers on polyurethane resin-based electrical insulators

    Directory of Open Access Journals (Sweden)

    Altafim Ruy Alberto Corrêa

    2003-01-01

    Full Text Available The increasingly widespread use of polymeric insulators in vehicle distributors and transmission systems has led to an ongoing quest for quality and low costs. This quest has, in turn, resulted in improved performance and cost benefits, brought about by the use of new polymeric and composite resins. Occasionally, however, while some properties are improved, others may show a loss of optimal performance. Therefore, to understand the behavior of fillers, such as carbon black, silica and mica added to castor oil-derived polyurethane resins, several thermal, mechanical and electrical tests were conducted on samples and insulators produced specifically for this purpose, using these new materials. The results of these tests clearly demonstrated that this type of resin and its composites can be used to manufacture indoor electrical insulators and that the fillers analyzed in this study improve or maintain the characteristics of the pure resins.

  11. Characterization of dielectric properties of nanocellulose from wood and algae for electrical insulator applications.

    Science.gov (United States)

    Le Bras, David; Strømme, Maria; Mihranyan, Albert

    2015-05-07

    Cellulose is one of the oldest electrically insulating materials used in oil-filled high-power transformers and cables. However, reports on the dielectric properties of nanocellulose for electrical insulator applications are scarce. The aim of this study was to characterize the dielectric properties of two nanocellulose types from wood, viz., nanofibrillated cellulose (NFC), and algae, viz., Cladophora cellulose, for electrical insulator applications. The cellulose materials were characterized with X-ray diffraction, nitrogen gas and moisture sorption isotherms, helium pycnometry, mechanical testing, and dielectric spectroscopy at various relative humidities. The algae nanocellulose sample was more crystalline and had a lower moisture sorption capacity at low and moderate relative humidities, compared to NFC. On the other hand, it was much more porous, which resulted in lower strength and higher dielectric loss than for NFC. It is concluded that the solid-state properties of nanocellulose may have a substantial impact on the dielectric properties of electrical insulator applications.

  12. Transport of electric charge in insulators

    International Nuclear Information System (INIS)

    Lopez C, E.

    1979-01-01

    In this work a review is made of important concepts in the study of the transport of electric charge in insulators. These concepts are: electrical contacts, transport regimes as viewed in the I-V characteristics, and photoinjection processes by internal photemission of holes or electrons from metals or semiconductors into insulators or by a virtual electrode using strongly absorbed light. Experimental results of photoinjection of holes and electrons into sulfur single crystals are analyzed using these concepts. The observation of the Mott-Gurney transition is reported for the first time. This is the transition between the region of space charge limited currents (SCLC) and the region of saturation of the current as a function of the applied voltage. A modified Mott-Gurney theoretical model is presented that is able to explain the whole I-V characteristic for uv and the internal photoemission of hopes and uv photoinjection of electrons. For the case of internal photoemission of electrons the conventional space charge limited current theory for an exponential distribution of traps is able to explain the experimental data. It is found that the crystals are of high purity since the total density of traps, as calculated from their exponential distribution, is Nsub(t) equals 1.8 X 10 14 cm -3 . (author)

  13. Cooling of electrically insulated high voltage electrodes down to 30 mK Kühlung von elektrisch isolierten Hochspannungselektroden bis 30 mK

    CERN Document Server

    Eisel, Thomas; Bremer, J

    2011-01-01

    The Antimatter Experiment: Gravity, Interferometry, Spectroscopy (AEGIS) at the European Organization for Nuclear Research (CERN) is an experiment investigating the influence of earth’s gravitational force upon antimatter. To perform precise measurements the antimatter needs to be cooled to a temperature of 100 mK. This will be done in a Penning trap, formed by several electrodes, which are charged with several kV and have to be individually electrically insulated. The trap is thermally linked to a mixing chamber of a 3He-4He dilution refrigerator. Two link designs are examined, the Rod design and the Sandwich design. The Rod design electrically connects a single electrode with a heat exchanger, immersed in the helium of the mixing chamber, by a copper pin. An alumina ring and the helium electrically insulate the Rod design. The Sandwich uses an electrically insulating sapphire plate sandwiched between the electrode and the mixing chamber. Indium layers on the sapphire plate are applied to improve the ther...

  14. Stressed state of a cement electrical insulation of a pulsed magnet

    International Nuclear Information System (INIS)

    Korenevskij, V.V.; Sugak, E.B.; Fedorenko, L.I.

    1985-01-01

    The stresses arising in cement electrical insulation of a pulsed magnet intended for separation and scanning of beam of secondary particles with 5-10 MeV energy are investigated during its switching. The magnet represents a single-turn construction. During its switching repulsion forces arise in copper buses which affect the core consisting of a set of iron plates. In its turn two cores trying to separate transmit impact load onto cement electrical insulation, the mechanical strength of which determines the construction durability on the whole. For selection of calculation technique the method of photoelasticity is used on models of transparent polymeric materials. Epoxy resin served as material for insulation model, duraluminium for the rest of magnet parts. It is concluded that the calculation technique for the magnet under investigation is a hingeless circular arc

  15. Radiaton-resistant electrical insulation on the base of cement binders

    International Nuclear Information System (INIS)

    Afanas'ev, V.V.; Korenevskij, V.V.; Pisachev, S.Yu.

    1985-01-01

    The problems of designing radiation-resistant electrical insulations on the base of BATs and Talum cements for the UNK magnets operating under constant and pulse modes are discussed. The data characterizing dielectrical ad physico-mechanical properties of 25 various compositions are given. Two variants of manufacturing coils are considered: solid and with the use of asbestos tape impregnated with aluminous cement solution. The data obtained testify to the fact that the advantages of insulation on Talum cement are raised radiation resistance, high strength (particularly compression strength), weak porosity, high elasticity modulus and high thermal conductivity. BATs cement insulation is characterized by high radiation resistance, absence of shrinkage, rather low elasticity modulus and high dielectrical characteristics under normal conditions. The qualities of the solid insulation variant are its high technological effectiveness and posibility to fill up the spaces of complex configuration. In case of using as solid insulation Talum cement, however special measures for moisture removal are required. The advantage of insulation on the base of the asbestos tape is its reliability. For complex configuration magnets, however to realize is such insulation somewhat difficult

  16. Intermetallic and electrical insulator coatings on high-temperature alloys in liquid-lithium environments

    International Nuclear Information System (INIS)

    Park, J.H.

    1994-06-01

    In the design of liquid-metal cooling systems for fusion-reactor blanket, applications, the corrosion resistance of structural materials and the magnetohydrodynamic (MHD) force and its subsequent influence on thermal hydraulics and corrosion are major concerns. When the system is cooled by liquid metals, insulator coatings are required on piping surfaces in contact with the coolant. The objective of this study is to develop stable corrosion-resistant electrical insulator coatings at the liquid-metal/structural-material interface, with emphasis on electrically insulating coatings that prevent adverse MHD-generated currents from passing through the structural wall, and Be-V intermetallic coatings for first-wall components that face the plasma. Vanadium and V-base alloys are leading candidate materials for structural applications in a fusion reactor. Various intermetallic films were produced on V-alloys and on Types 304 and 316 stainless steel. The intermetallic layers were developed by exposure of the materials to liquid Li containing 2 at temperatures of 500--1030 degree C. CaO electrical insulator coatings were produced by reaction of the oxygen-rich layer with <5 at. % Ca dissolved in liquid Li at 400--700 degree C. The reaction converted the oxygen-rich layer to an electrically insulating film. This coating method is applicable to reactor components because the liquid metal can be used over and over; only the solute within the liquid metal is consumed. This paper will discuss initial results on the nature of the coatings and their in-situ electrical resistivity characteristics in liquid Li at high temperatures

  17. Surface engineering of ferroelectric polymer for the enhanced electrical performance of organic transistor memory

    Science.gov (United States)

    Kim, Do-Kyung; Lee, Gyu-Jeong; Lee, Jae-Hyun; Kim, Min-Hoi; Bae, Jin-Hyuk

    2018-05-01

    We suggest a viable surface control method to improve the electrical properties of organic nonvolatile memory transistors. For viable surface control, the surface of the ferroelectric insulator in the memory field-effect transistors was modified using a smooth-contact-curing process. For the modification of the ferroelectric polymer, during the curing of the ferroelectric insulators, the smooth surface of a soft elastomer contacts intimately with the ferroelectric surface. This smooth-contact-curing process reduced the surface roughness of the ferroelectric insulator without degrading its ferroelectric properties. The reduced roughness of the ferroelectric insulator increases the mobility of the organic field-effect transistor by approximately eight times, which results in a high memory on–off ratio and a low-voltage reading operation.

  18. TFIIIC bound DNA elements in nuclear organization and insulation.

    Science.gov (United States)

    Kirkland, Jacob G; Raab, Jesse R; Kamakaka, Rohinton T

    2013-01-01

    tRNA genes (tDNAs) have been known to have barrier insulator function in budding yeast, Saccharomyces cerevisiae, for over a decade. tDNAs also play a role in genome organization by clustering at sites in the nucleus and both of these functions are dependent on the transcription factor TFIIIC. More recently TFIIIC bound sites devoid of pol III, termed Extra-TFIIIC sites (ETC) have been identified in budding yeast and these sites also function as insulators and affect genome organization. Subsequent studies in Schizosaccharomyces pombe showed that TFIIIC bound sites were insulators and also functioned as Chromosome Organization Clamps (COC); tethering the sites to the nuclear periphery. Very recently studies have moved to mammalian systems where pol III genes and their associated factors have been investigated in both mouse and human cells. Short interspersed nuclear elements (SINEs) that bind TFIIIC, function as insulator elements and tDNAs can also function as both enhancer - blocking and barrier insulators in these organisms. It was also recently shown that tDNAs cluster with other tDNAs and with ETCs but not with pol II transcribed genes. Intriguingly, TFIIIC is often found near pol II transcription start sites and it remains unclear what the consequences of TFIIIC based genomic organization are and what influence pol III factors have on pol II transcribed genes and vice versa. In this review we provide a comprehensive overview of the known data on pol III factors in insulation and genome organization and identify the many open questions that require further investigation. This article is part of a Special Issue entitled: Transcription by Odd Pols. Copyright © 2012 Elsevier B.V. All rights reserved.

  19. Design principles for handmade electrical insulation of superconducting joints in W7-X

    Energy Technology Data Exchange (ETDEWEB)

    Rummel, K., E-mail: kerstin.rummel@ipp.mpg.de [Max Planck Institute for Plasma Physics, EURATOM Association, Wendelsteinstr. 1, 17491 Greifswald (Germany); John, A. [Max Planck Institute for Plasma Physics, EURATOM Association, Wendelsteinstr. 1, 17491 Greifswald (Germany); Sulek, Z. [Henryk Niewodniczanski Institute of Nuclear Physics, Polish Academy of Sciences, Krakow, Radzikowskiego 152 (Poland)

    2013-10-15

    Highlights: ► In W-7X there are several types of handmade electrical insulation. ► In general insulation based on impregnated glass tapes and special G10 pieces. ► A proper overlapping of glass tapes turned out to be mandatory. ► Detailed qualification and training helps to minimize the failure rate. ► Visual inspection and Paschen tests after every insulation steps are important. -- Abstract: The superconducting magnet system of the Wendelstein 7-X (W7-X) experiment consists of 50 non-planar and 20 planar coils, 121 bus bars and 14 current leads. The connection between bus bars, coils and current leads will be provided by 198 joints. The joints have to be insulated manually during the assembly of the machine in constraint positions and a tight environment. In general the insulation is based on glass tapes impregnated with epoxy resin and special G10 insulating pieces embedded in the glass tape insulation. In critical areas Kapton{sup ®}-foils are embedded in the insulation. All types of insulation were qualified at mock-ups in a 1:1 model of the expected environment in W7-X. The qualification programme comprises thermal cycling between room temperature and 77 K and high voltage tests under air, under vacuum and under reduced pressure (Paschen test). The paper describes the main principles used for different types of handmade Paschen-tight insulations in W7-X and the visual and electrical tests during and after assembly.

  20. Fabrication and Measurement of Electroluminescence and Electrical Properties of Organic Light-Emitting Diodes Containing Mott Insulator Nanocrystals.

    Science.gov (United States)

    Nozoe, Soichiro; Kinoshita, Nobuaki; Matsuda, Masaki

    2016-04-01

    By using the short-time electrocrystallization technique, phthalocyanine (Pc)-based Mott insulator Co(Pc)(CN)2 . 2CHCl3 nanocrystals were fabricated and applied to organic light-emiting diodes (OLEDs). The fabricated device having the configuration ITO/Co(Pc)(CN)2 . 2CHCl3/Alq3/Al, in which ITO is indium-tin oxide and Alq3 is tris(8-hydroxyquinolinato)aluminum, showed clear emission from Alq3, suggesting the Mott insulator Co(Pc)(CN)2 . 2CHCl3 can work as useful hole-injection and transport material in OLEDs.

  1. Force microscopy on insulators: imaging of organic molecules

    International Nuclear Information System (INIS)

    Pfeiffer, O; Gnecco, E; Zimmerli, L; Maier, S; Meyer, E; Nony, L; Bennewitz, R; Diederich, F; Fang, H; Bonifazi, D

    2005-01-01

    So far, most of the high resolution scanning probe microscopy studies of organic molecules were restricted to metallic substrates. Insulating substrates are mandatory when the molecules need to be electrically decoupled in a electronic circuit. In such a case, atomic force microscopy is required. In this paper we will discuss our recent studies on different organic molecules deposited on KBr surfaces in ultra-high vacuum, and then imaged by AFM at room temperature. The distance between tip and surface was controlled either by the frequency-shift of the cantilever resonance or by the excitation signal required to keep the oscillation amplitude constant. Advantages and drawbacks of both techniques are discussed. The high mobility of the molecules, due to their weak interaction with the substrate, hinders the formation of regular self assembled structures. To overcome this problem we created artificial structures on the surface by annealing and by electron irradiation, which made possible the growth of the molecules onto step edges and their confinement into rectangular pits

  2. Converters and electric machines. Solid insulating materials. Electrical characteristics; Convertisseurs et machines electriques. Materiaux isolants solides. Caracteristiques electriques

    Energy Technology Data Exchange (ETDEWEB)

    Anton, A. [Institut National Superieur de Chimie Industrielle, 76 - Rouen (France)

    2003-08-01

    The aim of this article is to allow a preselection of a solid insulating material using the most common electrical characteristics: tangent of the loss angle, relative permittivity, dielectric rigidity, superficial resistivity, transverse resistivity, resistance to high voltage creeping spark currents, index of creeping resistance. The characteristics of the main solid insulating materials are presented in tables for: thermoplastics, thermosetting materials, natural insulating materials, mineral insulating materials, rubber and synthetic elastomers, stratified insulating materials, thermoplastic films, composite synthetic papers. A comparison is made between the different materials using the three properties: tangent of the loss angle, relative permittivity and resistance to HV spark creeping currents. (J.S.)

  3. Electrical resistivity study of insulators

    International Nuclear Information System (INIS)

    Liesegang, J.; Senn, B.C.; Holcombe, S.R.; Pigram, P.J.

    1998-01-01

    Full text: Conventional methods of electrical resistivity measurement of dielectric materials involve the application of electrodes to a sample whereby a potential is applied and a current through the material is measured. Although great care and ingenuity has often been applied to this technique, the recorded values of electrical resistivity (p), especially for insulator materials, show great disparity. In earlier work by the authors, a method for determining surface charge decay [Q(t)], using a coaxial cylindrical capacitor arrangement interfaced to a personal computer, was adapted to allow the relatively straightforward measurement of electrical resistivity in the surface region of charged insulator materials. This method was used to develop an ionic charge transport theory, based on Mott-Gurney diffusion to allow a greater understanding into charge transport behaviour. This theory was extended using numerical analysis to produce a two dimensional (2-D) computational model to allow the direct comparison between experimental and theoretical charge decay data. The work also provided a means for the accurate determination of the diffusion coefficient (D) and the layer of thickness of surface charge (Δz) on the sample. The work outlined here involves an extension of the theoretical approach previously taken, using a computational model based more closely on the 3-D experimental set-up, to reinforce the level of confidence in the results achieved for the simpler 2-D treatment. Initially, a 3-D rectangular box arrangement similar to the experimental set-up was modelled and a theoretical and experimental comparison of voltage decay results made. This model was then transferred into cylindrical coordinates to allow it to be almost identical to the experiment and again a comparison made. In addition, theoretical analysis of the coupled non-linear partial differential equations governing the charge dissipation process has led to a simplification involving directly, the

  4. Electrical and structural R&D activities on high voltage dc solid insulator in vacuum

    Energy Technology Data Exchange (ETDEWEB)

    Pilan, N., E-mail: nicola.pilan@igi.cnr.it [Consorzio RFX, Associazione EURATOM-ENEA sulla Fusione, Corso Stati Uniti 4, I-35127 Padova (Italy); Marcuzzi, D.; Rizzolo, A.; Grando, L.; Gambetta, G. [Consorzio RFX, Associazione EURATOM-ENEA sulla Fusione, Corso Stati Uniti 4, I-35127 Padova (Italy); Rosa, S. Dalla [Umicore – Italbras S.p.A., Strada del Balsego, n.6, 36100 Vicenza (Italy); Kraemer, V.; Quirmbach, T. [FRIATEC Ceramics Division, Steinzeugstrasse 50, 68229 Mannheim (Germany); Chitarin, G. [Consorzio RFX, Associazione EURATOM-ENEA sulla Fusione, Corso Stati Uniti 4, I-35127 Padova (Italy); Gobbo, R.; Pesavento, G. [DII, Università di Padova, v. Gradenigo 6/A, I-35131 Padova (Italy); De Lorenzi, A.; Lotto, L.; Rizzieri, R.; Fincato, M.; Romanato, L.; Trevisan, L.; Cervaro, V.; Franchin, L. [Consorzio RFX, Associazione EURATOM-ENEA sulla Fusione, Corso Stati Uniti 4, I-35127 Padova (Italy)

    2015-10-15

    Highlights: • A thorough R&D activity on the MITICA post insulator prototypes is being carried out. • The design has been numerically verified considering both mechanical and electrical aspects. • Experimental validation has been started, with positive results in both involved fields. • Alternative design solutions thickness have been proposed and successfully tested. - Abstract: This paper describes the R&D work performed in support of the design of the alumina insulators for the MITICA Neutral Beam Injector. The ceramic insulators are critical elements, both from the structural and electrical point of view, of the 1 MV electrostatic accelerator of the MITICA injector, as they are required to sustain both the mechanical loads due to the cantilevered weight of the ion source and the high electric field between the accelerator grids. This paper presents the results of numerical simulations and experimental tests on prototypes that have been carried out to validate the insulator design under realistic operating conditions.

  5. Electrical and structural R&D activities on high voltage dc solid insulator in vacuum

    International Nuclear Information System (INIS)

    Pilan, N.; Marcuzzi, D.; Rizzolo, A.; Grando, L.; Gambetta, G.; Rosa, S. Dalla; Kraemer, V.; Quirmbach, T.; Chitarin, G.; Gobbo, R.; Pesavento, G.; De Lorenzi, A.; Lotto, L.; Rizzieri, R.; Fincato, M.; Romanato, L.; Trevisan, L.; Cervaro, V.; Franchin, L.

    2015-01-01

    Highlights: • A thorough R&D activity on the MITICA post insulator prototypes is being carried out. • The design has been numerically verified considering both mechanical and electrical aspects. • Experimental validation has been started, with positive results in both involved fields. • Alternative design solutions thickness have been proposed and successfully tested. - Abstract: This paper describes the R&D work performed in support of the design of the alumina insulators for the MITICA Neutral Beam Injector. The ceramic insulators are critical elements, both from the structural and electrical point of view, of the 1 MV electrostatic accelerator of the MITICA injector, as they are required to sustain both the mechanical loads due to the cantilevered weight of the ion source and the high electric field between the accelerator grids. This paper presents the results of numerical simulations and experimental tests on prototypes that have been carried out to validate the insulator design under realistic operating conditions.

  6. Electrically and Thermally Insulated Joint for Liquid Nitrogen Transfer

    DEFF Research Database (Denmark)

    Rasmussen, Carsten; Jensen, Kim Høj; Holbøll, Joachim T.

    1999-01-01

    A prototype of a superconducting cable is currently under construction. The cable conductor is cooled by liquid nitrogen in order to obtain superconductivity. The peripheral cooling circuit is kept at ground potential. This requires a joint which insulates both electrically and thermally...

  7. Structural health monitoring of high voltage electrical switch ceramic insulators in seismic areas

    OpenAIRE

    REBILLAT, Marc; BARTHES, Clément; MECHBAL, Nazih; MOSALAM, Khalid M.

    2014-01-01

    International audience; High voltage electrical switches are crucial components to restart rapidly the electrical network right after an earthquake. But there currently exists no automatic procedure to check if these ceramic insulators have suffered after an earthquake, and there exists no method to recertify a given switch. To deploy a vibration-based structural health monitoring method on ceramic insulators a large shake table able to generate accelerations up to 3 g was used. The idea unde...

  8. Determination of the characteristics of an electric arc plasma contaminated by vapors from insulators

    International Nuclear Information System (INIS)

    Abbaoui, M.; Cheminat, B.

    1991-01-01

    An experimental study at atmospheric pressure carried out on plasma penetrated by vapors from different industrial insulators allowed the showing of the influence of the nature of the insulator upon the characteristics of the electric arc plasma; i.e., an increase of the temperature, electron density, electric field, and extinction velocity of the arc. Measurements have been made spectrometrically and by means of probes

  9. Electroluminescence and electrical degradation of insulating polymers at electrode interfaces under divergent fields

    Science.gov (United States)

    Zhang, Shuai; Li, Qi; Hu, Jun; Zhang, Bo; He, Jinliang

    2018-04-01

    Electrical degradation of insulating polymers at electrode interfaces is an essential factor in determining long-term reliability. A critical challenge is that the exact mechanism of degradation is not fully understood, either experimentally or theoretically, due to the inherent complex processes. Consequently, in this study, we investigate electroluminescence (EL) at the interface of an electrode and insulator, and determine the relationship between EL and electrical degradation. Using a tip-plate electrode structure, the unique features of EL under a highly divergent field are investigated. The voltage type (alternating or direct current), the polymer matrix, and the time of pressing are also investigated separately. A study of EL from insulators under a divergent field is provided, and the relationship between EL spectra and degradation is discussed. It is shown that EL spectra under a divergent field have unique characteristics compared with EL spectra from polymer films under a uniform field and the most obvious one is the UV emission. The results obtained in the current investigation bring us a step closer to understanding the process of electrical degradation and provide a potential way to diagnose insulator defects.

  10. Electric cable insulation pyrolysis and ignition resulting from potential hydrogen burn scenarios for nuclear containment buildings

    International Nuclear Information System (INIS)

    Berlad, A.L.; Jaung, R.; Pratt, W.T.

    1982-01-01

    Electric cable insulation in nuclear containment buildings may participate in pyrolysis and combustion processes engendered by hydrogen burn phenomena. This paper examines these pyrolysis/ignition processes of those polymeric materials present in the electric cable insulation and their possible relation to hydrogen burn scenarios

  11. Field-dependent molecular ionization and excitation energies: Implications for electrically insulating liquids

    Directory of Open Access Journals (Sweden)

    N. Davari

    2014-03-01

    Full Text Available The molecular ionization potential has a relatively strong electric-field dependence as compared to the excitation energies which has implications for electrical insulation since the excited states work as an energy sink emitting light in the UV/VIS region. At some threshold field, all the excited states of the molecule have vanished and the molecule is a two-state system with the ground state and the ionized state, which has been hypothesized as a possible origin of different streamer propagation modes. Constrained density-functional theory is used to calculate the field-dependent ionization potential of different types of molecules relevant for electrically insulating liquids. The low singlet-singlet excitation energies of each molecule have also been calculated using time-dependent density functional theory. It is shown that low-energy singlet-singlet excitation of the type n → π* (lone pair to unoccupied π* orbital has the ability to survive at higher fields. This type of excitation can for example be found in esters, diketones and many color dyes. For alkanes (as for example n-tridecane and cyclohexane on the other hand, all the excited states, in particular the σ → σ* excitations vanish in electric fields higher than 10 MV/cm. Further implications for the design of electrically insulating dielectric liquids based on the molecular ionization potential and excitation energies are discussed.

  12. Electrical Performance of Distribution Insulators with Chlorella vulgaris Growth on its Surface

    Directory of Open Access Journals (Sweden)

    Herbert Enrique Rojas Cubides

    2015-06-01

    Full Text Available This paper presents a study about electrical performance of ceramic and polymeric insulators bio-contaminated with alga Chlorella vulgaris. The performed tests involve ANSI 55-2 and ANSI 52-1 ceramic insulators and ANSI DS-15 polymeric insulators, all of them used in distribution systems of Colombia. Biological contamination of insulators is realized using a controlled environment chamber that adjusts the temperature, humidity and light radiation. The laboratory tests include measurements of flashover voltages and leakage currents and they were performed to determine how insulators are affected by biological contamination. After a series of laboratory tests, it was concluded that the presence of Chlorella vulgaris on the contaminated ceramic insulators reduces the wet flashover voltage up to 12% and increases their leakage currents up to 80%. On the other hand, for polymeric insulators the effect of algae growth on flashover voltages was not to strong, although the leakage currents increase up to 60%.

  13. A Study of the Properties of Electrical Insulation Oils and of the Components of Natural Oils

    Directory of Open Access Journals (Sweden)

    Milan Spohner

    2012-01-01

    Full Text Available This paper presents a study of the electrical and non-electrical properties of insulating oils. For the correct choice of an electrical insulation oil, it is necessary to know its density, dynamic viscosity, dielectric constant, loss number and conductivity, and the effects of various exposure factors. This paper deals with mathematical and physical principles needed for studying and making correct measurements of the dynamic viscosity, density and electrical properties of insulation oils. Rheological properties were measured using an A&D SV-10 vibratory viscometer, and analytical balance with density determination kit, which operates on the principle of Archimedes’ law. Dielectric properties were measured using a LCR meter Agilent 4980A with connected with the Agilent 16452A test fixture for dielectric liquids.

  14. Effects of ionizing radiation of electrical properites of refractory insulators

    International Nuclear Information System (INIS)

    van Lint, V.A.J.; Bunch, J.M.

    1975-01-01

    The Los Alamos Reference Theta Pinch Reactor (RTPR) requires on the first wall an electrical insulator which will withstand transient high voltage at high temperature 10 sec after severe neutron and ionizing irradiation. Few measurements of electrical parameters for heavily disordered refractory insulators have been reported; estimates are made as to whether breakdown strength or conductivity will be degraded by the irradiation. The approach treats separately short-term ionization effects (free and trapped electrons and holes) and long-term gross damage effects (transmutation products and various lattice defects). The following processes could produce unacceptable conduction across the first wall insulator: (a) delayed electronic conductivity 10 sec after the prompt ionization by bremsstrahlung; (b) prompt electronic conductivity from delayed ionization; (c) electronic breakdown; (d) electronic or ionic conductivity due to thermal motion in the disordered material, possibly leading to thermal breakdown. Worst-case calculations based on lower limits to recombination coefficients limit process (a) to sigma much less than 5 x 10 -14 mho/cm. Data on ionization-induced conductivity in insulators predict for process (b) sigma much less than 10 -8 mho/cm. Electronic breakdown generally occurs at fields well above the 10 5 V/cm required for RTPR. Thermal breakdown is negligible due to the short voltage pulse. Ionic and electronic conduction must be studied theoretically and experimentally in the type of highly disordered materials that result from neutron irradiation of the first wall

  15. Electrically tuned magnetic order and magnetoresistance in a topological insulator.

    Science.gov (United States)

    Zhang, Zuocheng; Feng, Xiao; Guo, Minghua; Li, Kang; Zhang, Jinsong; Ou, Yunbo; Feng, Yang; Wang, Lili; Chen, Xi; He, Ke; Ma, Xucun; Xue, Qikun; Wang, Yayu

    2014-09-15

    The interplay between topological protection and broken time reversal symmetry in topological insulators may lead to highly unconventional magnetoresistance behaviour that can find unique applications in magnetic sensing and data storage. However, the magnetoresistance of topological insulators with spontaneously broken time reversal symmetry is still poorly understood. In this work, we investigate the transport properties of a ferromagnetic topological insulator thin film fabricated into a field effect transistor device. We observe a complex evolution of gate-tuned magnetoresistance, which is positive when the Fermi level lies close to the Dirac point but becomes negative at higher energies. This trend is opposite to that expected from the Berry phase picture, but is intimately correlated with the gate-tuned magnetic order. The underlying physics is the competition between the topology-induced weak antilocalization and magnetism-induced negative magnetoresistance. The simultaneous electrical control of magnetic order and magnetoresistance facilitates future topological insulator based spintronic devices.

  16. Investigation of electrophysical properties of electrical insulating materials under neutron irradiation

    International Nuclear Information System (INIS)

    Skornyakov, Yu.A.; Stepanov, A.N.; Lapenas, A.A.

    1978-01-01

    The possibilities of applicaiton of insulating materials on the basis of glass cloths in electric windings for operation under neutron radiation of thermonuclear devices are studied. Changes in the specimen resistance, tangent of the angle of dielectric losses, electric strength according to the value of neutron fluence are determined. The temperature regimes are also studied. The data indicate the irreversible changes in the composition and structure of the polymer material under irradiation. The LSMI 228L-80 glass cloth has the highest radiation resistance. The necessity of forced cooling of large-sized specimens under the neutron radiation the IRT-200 reactor is established. The presence of impurities leading to the long-term induced activity of the insulating materials ( 59 Fe, 60 Co) is determined

  17. Electrical insulating liquid: A review

    Directory of Open Access Journals (Sweden)

    Deba Kumar Mahanta

    2017-08-01

    Full Text Available Insulating liquid plays an important role for the life span of the transformer. Petroleum-based mineral oil has become dominant insulating liquid of transformer for more than a century for its excellent dielectric and cooling properties. However, the usage of petroleum-based mineral oil, derived from a nonrenewable energy source, has affected the environment for its nonbiodegradability property. Therefore, researchers direct their attention to renewable and biodegradable alternatives. Palm fatty acid ester, coconut oil, sunflower oil, etc. are considered as alternatives to replace mineral oil as transformer insulation liquid. This paper gives an extensive review of different liquid insulating materials used in a transformer. Characterization of different liquids as an insulating material has been discussed. An attempt has been made to classify different insulating liquids-based on different properties.

  18. Radiation Crosslinking of Small Electrical Wire Insulator Fabricated from NR-LDPE Blend

    International Nuclear Information System (INIS)

    Chyagrit, S.

    2006-01-01

    Blending of block natural rubber (STR-5L) and LDPE with phthalic anhydride (PA) as copatibilizer was put to the test for the purpose of a fabrication into small electrical wire insulator. It was found that PA at concentration of 1.0 - 1.5% in NR/PE of 50/50 so fabricated into the insulator, after gamma ray cross-linked at a dose of 180 kGy in limited air, could meet Thai Industrial Standard (TIS) 11-2531 of small eletrical insulator (<300 V). Effect of radiation dose on tensile, hardness, elongation at break, modulus 100%, limiting oxigen index (LOI) were investigated. It was noted that to comply with TIS 11-2531 for vertical flame retardance test, a suitable flame retardance was needed for the insulator

  19. Electrically insulating films deposited on V-4%Cr-4%Ti by reactive CVD

    International Nuclear Information System (INIS)

    Park, J.H.

    1998-04-01

    In the design of liquid-metal blankets for magnetic fusion reactors, corrosion resistance of structural materials and the magnetohydrodynamic forces and their influence on thermal hydraulics and corrosion are major concerns. Electrically insulating CaO films deposited on V-4%Cr-4%Ti exhibit high-ohmic insulator behavior even though a small amount of vanadium from the alloy become incorporated into the film. However, when vanadium concentration in the film is > 15 wt.%, the film becomes conductive. When the vanadium concentration is high in localized areas, a calcium vanadate phase that exhibits semiconductor behavior can form. The objective of this study is to evaluate electrically insulating films that were deposited on V-4%Cr-4%Ti by a reactive chemical vapor deposition (CVD) method. To this end, CaO and Ca-V-O coatings were produced on vanadium alloys by CVD and by a metallic-vapor process to investigate the electrical resistance of the coatings. The authors found that the Ca-V-O films exhibited insulator behavior when the ratio of calcium concentration to vanadium concentration R in the film > 0.9, and semiconductor or conductor behavior when R 0.98 were exposed in liquid lithium. Based on these studies, they conclude that semiconductor behavior occurs if a conductive calcium vanadate phase is present in localized regions in the CaO coating

  20. Insulators for fusion applications

    International Nuclear Information System (INIS)

    1987-04-01

    Design studies for fusion devices and reactors have become more detailed in recent years and with this has come a better understanding of requirements and operating conditions for insulators in these machines. Ceramic and organic insulators are widely used for many components of fusion devices and reactors namely: radio frequency (RF) energy injection systems (BeO, Al 2 O 3 , Mg Al 2 O 4 , Si 3 N 4 ); electrical insulation for the torus structure (SiC, Al 2 O 3 , MgO, Mg Al 2 O 4 , Si 4 Al 2 O 2 N 6 , Si 3 N 4 , Y 2 O 3 ); lightly-shielded magnetic coils (MgO, MgAl 2 O 4 ); the toroidal field coil (epoxies, polyimides), neutron shield (B 4 C, TiH 2 ); high efficiency electrical generation; as well as the generation of very high temperatures for high efficiency hydrogen production processes (ZrO 2 and Al 2 O 3 - mat, graphite and carbon - felt). Timely development of insulators for fusion applications is clearly necessary. Those materials to be used in fusion machines should show high resistance to radiation damage and maintain their structural integrity. Now the need is urgent for a variety of radiation resistant materials, but much effort in these areas is required for insulators to be considered seriously by the design community. This document contains 14 papers from an IAEA meeting. It was the objective of this meeting to identify existing problems in analysing various situations of applications and requirements of electrical insulators and ceramics in fusion and to recommend strategies and different stages of implementation. This meeting was endorsed by the International Fusion Research Council

  1. Phase-field model of insulator-to-metal transition in VO2 under an electric field

    Science.gov (United States)

    Shi, Yin; Chen, Long-Qing

    2018-05-01

    The roles of an electric field and electronic doping in insulator-to-metal transitions are still not well understood. Here we formulated a phase-field model of insulator-to-metal transitions by taking into account both structural and electronic instabilities as well as free electrons and holes in VO2, a strongly correlated transition-metal oxide. Our phase-field simulations demonstrate that in a VO2 slab under a uniform electric field, an abrupt universal resistive transition occurs inside the supercooling region, in sharp contrast to the conventional Landau-Zener smooth electric breakdown. We also show that hole doping may decouple the structural and electronic phase transitions in VO2, leading to a metastable metallic monoclinic phase which could be stabilized through a geometrical confinement and the size effect. This work provides a general mesoscale thermodynamic framework for understanding the influences of electric field, electronic doping, and stress and strain on insulator-to-metal transitions and the corresponding mesoscale domain structure evolution in VO2 and related strongly correlated systems.

  2. Insulating materials resistance in intense radiation beams

    International Nuclear Information System (INIS)

    Oproiu, Constantin; Martin, Diana; Scarlat, Florin; Timus, Dan; Brasoveanu, Mirela; Nemtanu, Monica

    2002-01-01

    The paper emphasizes the main changes of the mechanical and electrical properties of some organic insulating materials exposed to accelerated electron beams. These materials are liable to be used in nuclear plants and particle accelerators. The principal mechanical and electrical properties analyzed were: tensile strength, fracture strength, tearing on fracture, dielectric strength, electrical resistivity, dielectric constant and tangent angle of dielectric losses. (authors)

  3. Testing electrical insulation of LCT coils and instrumentation

    International Nuclear Information System (INIS)

    Luton, J.N.; Ulbricht, A.R.; Ellis, J.F.; Shen, S.S.; Wilson, C.T.; Okuno, K.; Siewerdt, L.O.; Zahn, G.R.; Zichy, J.A.

    1986-09-01

    Three of the superconducting test coils in the Large Coil Task (LCT) use conductors cooled internally by forced flow of helium. In the other three coils, the conductors are cooled externally by a bath of helium. The coils and facility are designed for rapid discharges (dumps) at voltages up to 2.5 kV, depending on coil design. Many coil sensors are connected electrically to the conductors. These sensor leads and signal conditioning equipment also experience high voltage. High-potential tests of ground insulation were performed on all components of the International Fusion Superconducting Magnet Test Facility (IFSMTF). Coil insulation was also tested by ring-down tests that produced voltage distributions within the coils like those occurring during rapid discharge. Methods were developed to localize problem areas and to eliminate them. The effect on breakdown voltage near the Paschen minimum of magnetic fields up to 2 T was investigated

  4. Space Charge Modulated Electrical Breakdown of Oil Impregnated Paper Insulation Subjected to AC-DC Combined Voltages

    Directory of Open Access Journals (Sweden)

    Yuanwei Zhu

    2018-06-01

    Full Text Available Based on the existing acknowledgment that space charge modulates AC and DC breakdown of insulating materials, this investigation promotes the related investigation into the situations of more complex electrical stress, i.e., AC-DC combined voltages. Experimentally, the AC-DC breakdown characteristics of oil impregnated paper insulation were systematically investigated. The effects of pre-applied voltage waveform, AC component ratio, and sample thickness on AC-DC breakdown characteristics were analyzed. After that, based on an improved bipolar charge transport model, the space charge profiles and the space charge induced electric field distortion during AC-DC breakdown were numerically simulated to explain the differences in breakdown characteristics between the pre-applied AC and pre-applied DC methods under AC-DC combined voltages. It is concluded that large amounts of homo-charges are accumulated during AC-DC breakdown, which results in significantly distorted inner electric field, leading to variations of breakdown characteristics of oil impregnated paper insulation. Therefore, space charges under AC-DC combined voltages must be considered in the design of converter transformers. In addition, this investigation could provide supporting breakdown data for insulation design of converter transformers and could promote better understanding on the breakdown mechanism of insulating materials subjected to AC-DC combined voltages.

  5. Impact of steep-front short-duration impulse on electric power system insulation

    Energy Technology Data Exchange (ETDEWEB)

    Burrage, L M; Veverka, E F; Shaw, J H [Cooper Industries, Inc., Franksville, WI (USA). Cooper Power Systems; McConnell, B W [Oak Ridge National Lab., TN (USA)

    1991-04-01

    This research effort required the performance evaluation of three specific insulation systems in common usage by electric power transmission and distribution utilities under stresses imposed by: three characteristic impulse waveforms (two waves representative of steep-front short duration (SFSD) impulses and one representative of lightning), the cumulative effect of multiple shots'' of each pulse, 60 Hz voltage, and, where appropriate, and mechanical load. The insulation systems evaluated are the cellulose-paper/oil combination typical of power transformer and condenser bushing usage, the cellulose-paper/enamel/oil combination used in distribution transformer construction, and the porcelain/air combination representing transmission and distribution line structural insulation. 4 refs., 94 figs., 11 tabs.

  6. Electric properties of semi-insulating crystals CdTe:Cl

    International Nuclear Information System (INIS)

    Arkadyeva, E.N.; Matveev, O.A.

    1977-01-01

    Hall effect and conductivity measurement were carried out on chlorine doped semi-insulating CdTe crystals, of p and n electric type. In p type crystals the depth of the dominating level was determined (+0.7eV) as well as the concentration of associated centres (10 13 -10 14 cm -3 ). The mobility values are limited by a process of diffusion on heterogeneities

  7. Organic Insulation Materials, the Effect on Indoor Humidity, and the Necessity of a Vapor Barrier

    DEFF Research Database (Denmark)

    Rode, Carsten

    1998-01-01

    Examples of organic insulation products are cellulose fiber, other plant fiber, and animal wool. These materials, which are all very hygroscopic, are associated with certain assertions about their building physical behavior that need to be verified.Examples of such assertions are: "A vapor barrier...... is not needed when using organic insulation materials" and "Organic insulation materials have a stabilizing effect on the indoor humidity".The paper presents some numerical analyses of the hygrothermal behavior of wall constructions and the occupied spaces they surround when an organic insulation material...

  8. Overview and statistical failure analyses of the electrical insulation system for the SSC long dipole magnets from an industrialization point of view

    International Nuclear Information System (INIS)

    Roach, J.F.

    1992-01-01

    The electrical insulation system of the SSC long dipole magnets is reviewed and potential dielectric failure modes discussed. Electrical insulation fabrication and assembly issues with respect to rate production manufacturability are addressed. The automation required for rate assembly of electrical insulation components will require critical online visual and dielectric screening tests to insure production quality. Storage and assembly areas must bc designed to prevent foreign particles from becoming entrapped in the insulation during critical coil winding, molding, and collaring operations. All hand assembly procedures involving dielectrics must be performed with rigorous attention to their impact on insulation integrity. Individual dipole magnets must have a sufficiently low probability of electrical insulation failure under all normal and fault mode voltage conditions such that the series of magnets in the SSC rings have acceptable Mean Time Between Failure (MTBF) with respect to dielectric mode failure events. Statistical models appropriate for large electrical system breakdown failure analysis are applied to the SSC magnet rings. The MTBF of the SSC system is related to failure data base for individual dipole magnet samples

  9. Organic filler from golden apple snails shells to improve the silicone rubber insulator properties

    Science.gov (United States)

    Tepsila, Sujirat; Suksri, Amnart

    2018-02-01

    This paper investigates the effect of an addition of filler compound using golden apple snail shell as an organic filler to the silicone rubber insulator. The filler obtained from golden apple snail shell is found mostly contained calcium carbonate. The organic calcium carbonate (CaCO3) with particle size of 45, 75, 100 and 300 micron were prepared. Sample of silicone rubber that were filled with fillers were tested under ASTM D638-02a type standard for mechanical test. Also, electrical test such as I-V characteristics (ASTM D257-07) and dry arc test according to ASTM D495-14 have been performed. The results revealed that using larger particle size of organic filler obtained from the golden apple snail shell resulted to higher value of dielectric constant as well as higher dielectric strength. Also, the filler helps slow down the tracking activity at an insulator surface due to its crystals of calcium carbonate. However, when using excessive amount of filler, the sample will have a drawbacks in mechanical properties. By using agriculture waste as a filler compound, one can reduced the usage of commercial CaCO3 as an inorganic materials and to lower the investment cost to a final silicone rubber product.

  10. Composite bulk Heat Insulation Made of loose Mineral and Organic Aggregate

    Directory of Open Access Journals (Sweden)

    Namsone Eva

    2015-12-01

    Full Text Available The task of building energy-efficiency is getting more important. Every house owner wishes to save up exploitation costs of heating, cooling, hot water production, ventilation, etc. and find cost-effective investments. One of the ways to reduce greenhouse gas emissions (GHGE is to minimize the heat transfer through the building by insulating it. Loose heat insulation is a good alternative to traditional board insulation, it is simple in use and cost-effective. Main drawback of this insulation is tendency to compact during exploitation. In the frame of this research composite loose heat insulation is elaborated, consisting on porous mineral foamed glass aggregate and local organic fiber materials (hemp and flaxen shives. Composite bulk insulation is an alternative solution which combines heat insulating properties and mechanical stability.

  11. High Voltage Hybrid Electric Propulsion - Multilayered Functional Insulation System (MFIS) NASA-GRC

    Science.gov (United States)

    Lizcano, M.

    2017-01-01

    High power transmission cables pose a key challenge in future Hybrid Electric Propulsion Aircraft. The challenge arises in developing safe transmission lines that can withstand the unique environment found in aircraft while providing megawatts of power. High voltage AC, variable frequency cables do not currently exist and present particular electrical insulation challenges since electrical arcing and high heating are more prevalent at higher voltages and frequencies. Identifying and developing materials that maintain their dielectric properties at high voltage and frequencies is crucial.

  12. Development of high-mechanical strength electrical insulations for tokamak toroidal field coils

    International Nuclear Information System (INIS)

    Burke, C.

    1977-01-01

    The electrical insulation for the TF (Toroidal Field) coils is subjected to a high interlaminar shear, tensile and compressive stresses. Two candidate epoxy/glass fiber systems using prepreg and vacuum impregnation techniques were evaluated. Specimens were prepared and processed under controlled conditions to simulate specification manufacturing procedures. The strengths of the insulation were measured in interlaminar shear, tension, compression, and combined shear and compression statically. Shear modulus determinations were also made. Various techniques of surface treatments to increase bond strengths with three resin primers were tested

  13. Evaluation of diagnostic technique for degradation of low-voltage electric cables with silicone rubber insulator

    International Nuclear Information System (INIS)

    Mikami, Masao

    2005-01-01

    As a part of countermeasures against ageing problems of nuclear power plants, it is requested to establish non-destructive diagnostic technique for their degradation of low voltage electric cables and assessment standard of their life. Having aimed at investigating the degradation of low-voltage electric cable with silicone rubber insulator, change of its surface hardness at elevated temperature were measured by indenter modules. Moreover, we also measured the elongation at break, which is regarded as general degradation index of electric cables, and the surface hardness with a micro hardness meter. Consequently, it is seen that the indenter modulus measurement is (1) capable to obtain general feature of the thermal degradation of silicone rubber insulator, (2) applicable to diagnose the degree of degradation of the electric cable by converting the result to elongation at break, (3) well correlated with the hardness measurement of the electric cable with the micro hardness meter. (author)

  14. Electric Field and Current Density Performance Analysis of Sf6, C4f8 and CO2 Gases As An Insulation

    Science.gov (United States)

    Mazli, Ahmad Danial Ahmad; Jamail, Nor Akmal Mohd; Azlin Othman, Nordiana

    2017-08-01

    SF6 gases are not only widely used as an insulating component in electric power industry but also as an arc extinguishing performance in high voltage (HV) gas-insulated circuit breaker (GCB). SF6 gases is generally used in the production of semiconductor materials and devices. Though these gasses is widely used in many application, the presences of temperature hotspot in the insulations may affect the insulation characteristics particularly electric field and current density. Therefore, it is important to determine the relationship between electric field and current density of gasses used in the insulator in the presence of hotspot. In this paper, three types of gases in particular Sulphur Hexafluoride (SF6), Octafluorocylobutane (C4F8), and Carbon Dioxide (CO2) was used in the insulator for gas insulation with the presence of two hotspots. These two hotspost were detected by referring the rising temperature in the insulator which are 1000 and 2000 Kelvin temperature for hotspot 1 and hotspot 2, respectively. From the simulation results, it can be concluded that Sulphur Hexafluoride (SF6) is the best choice for gas insulation since it had the lowest current density and electric field compared to Octafluorocylobutane (C4F8), and Carbon Dioxide (CO2). It is observed that the maximum current density and electric field for SF6 during normal condition are 358.94 × 103 V/m and 0.643 × 109 A/m2, respectively. Meanwhile, during temperature rising at hotspot 1 and hotspot 2, SF6 also had lowest current density and electric field compared to the other gasses where the results for Emax and Jmax at hotspot 1 are 322.34 × 103 V/m and 1.934 × 109 A/m2, respectively; While, Emax and Jmax at hotspot 2 are 259.77× 103 V/m and 2.824 × 109 A/m2. The results of this analysis can be used to find the best choices of gas that can be used in the insulator.

  15. A Classroom Activity for Teaching Electric Polarization of Insulators and Conductors

    Science.gov (United States)

    Deligkaris, Christos

    2018-01-01

    The phenomenon of electric polarization is crucial to student understanding of forces exerted between charged objects and insulators or conductors, the process of charging by induction, and the behavior of electroscopes near charged objects. In addition, polarization allows for microscopic-level models of everyday-life macroscopic-level phenomena.…

  16. A flexible Li-ion battery with design towards electrodes electrical insulation

    Science.gov (United States)

    Vieira, E. M. F.; Ribeiro, J. F.; Sousa, R.; Correia, J. H.; Goncalves, L. M.

    2016-08-01

    The application of micro electromechanical systems (MEMS) technology in several consumer electronics leads to the development of micro/nano power sources with high power and MEMS integration possibility. This work presents the fabrication of a flexible solid-state Li-ion battery (LIB) (~2.1 μm thick) with a design towards electrodes electrical insulation, using conventional, low cost and compatible MEMS fabrication processes. Kapton® substrate provides flexibility to the battery. E-beam deposited 300 nm thick Ge anode was coupled with LiCoO2/LiPON (cathode/solid-state electrolyte) in a battery system. LiCoO2 and LiPON films were deposited by RF-sputtering with a power source of 120 W and 100 W, respectively. LiCoO2 film was annealed at 400 °C after deposition. The new design includes Si3N4 and LiPO thin-films, providing electrode electrical insulation and a battery chemical stability safeguard, respectively. Microstructure and battery performance were investigated by scanning electron microscopy, electric resistivity and electrochemical measurements (open circuit potential, charge/discharge cycles and electrochemical impedance spectroscopy). A rechargeable thin-film and lightweight flexible LIB using MEMS processing compatible materials and techniques is reported.

  17. Effects of gamma-rays irradiation on tracking resistance of organic insulating materials

    Energy Technology Data Exchange (ETDEWEB)

    Du, Boxue; Suzuki, Akio; Kobayashi, Shigeo [Tokyo Univ. of Agriculture and Technology, Koganei (Japan). Faculty of Technology

    1996-04-01

    This paper describes the influence of gamma-rays irradiation on tracking failure of organic insulating materials by use of the IEC Publ.112 method. Tracking resistance of organic insulating materials under wet polluted condition has been studied by many investigators with a test method of the IEC Publ.112. The investigations on irradiation effects on tracking resistance should be enhanced due to the increasing usage of organic insulating materials in the radiation environments. The tracking resistance seems to be affected by gamma-irradiation, but the knowledge on the influence of gamma-irradiation is quite a few and systematic studies are needed. In this paper, modified polyphenylene oxide, polybutylene naphthalate, modified polycarbonate and polybutylene terephthalate which were irradiated in air until 1x10{sup 7}R and 1x10{sup 8}R with dose rate of 10{sup 6}R/hr using {sup 60}Co gamma-source have been employed. The total dose effects on the number of drops to tracking failure, contact angle and charges of scintillation have been studied. As the total doses are increased, the number of drops to tracking failure decreases with polybutylene terephthalate. On the other hand, the number of drops to tracking failure increases with polybutylene naphthalate and modified polycarbonate when the total doses are increased. The effects of gamma-rays irradiation on tracking failure are due to radiation-induced degradation or cross-linking of organic insulating materials. When the organic insulating materials are degraded by gamma-irradiation, the tracking resistance decreases, but for cross-linking type materials, the tracking resistance increases. (author)

  18. Development of electrically insulating coatings for service in a lithium environment

    International Nuclear Information System (INIS)

    Natesan, K.; Uz, M.; Wieder, S.

    2000-01-01

    Several experiments were conducted to develop electrically insulating CaO coatings on a V-4Cr-4Ti alloy for application in an Li environment. The coatings were developed by vapor phase transport external to Li, and also in-situ in an Li-Ca environment at elevated temperature. In the vapor phase study, several geometrical arrangements were examined to obtain a uniform coating of Ca on the specimens, which were typically coupons measuring 5 to 10 x 5 x 1 mm. After Ca deposition from the vapor phase, the specimens were oxidized in a high-purity argon environment at 600 C to convert the deposited metal into oxide. The specimens exhibited insulating characteristics after this oxidation step. Several promising coated specimens were then exposed to high-purity Li at 500 C for 48--68 h to determine coating integrity. Microstructural characteristics of the coatings were evaluated by scanning electron microscopy and energy-dispersive X-ray analysis. Electrical resistances of the coatings were measured by a two-probe method between room temperature and 700 C before and after exposure to Li

  19. Trapping-charging ability and electrical properties study of amorphous insulator by dielectric spectroscopy

    International Nuclear Information System (INIS)

    Mekni, Omar; Arifa, Hakim; Askri, Besma; Yangui, Béchir; Raouadi, Khaled; Damamme, Gilles

    2014-01-01

    Usually, the trapping phenomenon in insulating materials is studied by injecting charges using a Scanning Electron Microscope. In this work, we use the dielectric spectroscopy technique for showing a correlation between the dielectric properties and the trapping-charging ability of insulating materials. The evolution of the complex permittivity (real and imaginary parts) as a function of frequency and temperature reveals different types of relaxation according to the trapping ability of the material. We found that the space charge relaxation at low frequencies affects the real part of the complex permittivity ε ′ and the dissipation factor Tan(δ). We prove that the evolution of the imaginary part of the complex permittivity against temperature ε ″ =f(T) reflects the phenomenon of charge trapping and detrapping as well as trapped charge evolution Q p (T). We also use the electric modulus formalism to better identify the space charge relaxation. The investigation of trapping or conductive nature of insulating materials was mainly made by studying the activation energy and conductivity. The conduction and trapping parameters are determined using the Correlated Barrier Hopping (CBH) model in order to confirm the relation between electrical properties and charge trapping ability.

  20. Production of a nuclear radiation resistant and mechanically tough electrically insulating material

    International Nuclear Information System (INIS)

    Brechna, H.

    1975-01-01

    According to the invention, an electrically insulating material of high mechanical strength and resistance to nuclear radiation may be made of a hardenable plastic material coated on an inorganic supporting tissue. The synthetic resin serving as binder - duroplasts, e.g. epoxide resins, polyester resins or silicon resins - is heated, mixed with a catalyst, a wetting agent and a filler (and, if required, with 0.5-1.5 weight % thixotropic material) and coated, under reduced pressure (o.4 to 0.6 mm Hg), on the supporting tissue whose surface is cleaned before this by heating. It is then hardened. Hardening may also take place directly on the electric conductor to be insulated. One obtains a bubble-free wire coating. The inorganic supporting material is glas fibre tissue, also in combination with mica, while Al 2 O 3 , zirconium, zirconia, magnesium oxide, mica and silica (grain size 10-20 μ). The invention is illustrated by a number of examples. (UWI) [de

  1. The Use of Ferroelectrics and Dipeptides as Insulators in Organic Field-Effect Transistor Devices

    Science.gov (United States)

    Knotts, Grant

    While the electrical transport characteristics of organic electronic devices are generally inferior to their inorganic counterparts, organic materials offer many advantages over inorganics. The materials used in organic devices can often be deposited using cheap and simple processing techniques such as spincoating, inkjet printing, or roll-to-roll processing; allow for large-scale, flexible devices; and can have the added benefits of being transparent or biodegradable. In this manuscript, we examine the role of solvents in the performance of pentacene-based devices using the ferroelectric copolymer polyvinylidene fluoride-trifluoroethylene (PVDF-TrFe) as a gate insulating layer. High dipole moment solvents, such as dimethyl sulfoxide, used to dissolve the copolymer for spincoating increase the charge carrier mobility in field-effect transistors (FETs) by nearly an order of magnitude as compared to lower dipole moment solvents. The polarization in Al/PVDF-TrFe/Au metal-ferroelectric-metal devices also shows an increase in remnant polarization of 20% in the sample using dimethyl sulfoxide as the solvent for the ferroelectric. Interestingly, at low applied electric fields of 100 MV/m a remnant polarization is seen in the high dipole moment device that is nearly 3.5 times larger than the value observed in the lower dipole moment samples, suggesting that the degree of dipolar order is higher at low operating voltages for the high dipole moment device. We will also discuss the use of peptide-based nanostructures derived from natural amino acids as building blocks for biocompatible devices. These peptides can be used in a bottom-up process without the need for expensive lithography. Thin films of L,L-diphenylalanine micro/nanostructures (FF-MNSs) were used as the dielectric layer in pentacene-based FETs and metal-insulator-semiconductor diodes both in bottom-gate and top-gate structures. It is demonstrated that the FFMNSs can be functionalized for detection of enzyme

  2. Electric-field driven insulator-metal transition and tunable magnetoresistance in ZnO thin film

    Science.gov (United States)

    Zhang, Le; Chen, Shanshan; Chen, Xiangyang; Ye, Zhizhen; Zhu, Liping

    2018-04-01

    Electrical control of the multistate phase in semiconductors offers the promise of nonvolatile functionality in the future semiconductor spintronics. Here, by applying an external electric field, we have observed a gate-induced insulator-metal transition (MIT) with the temperature dependence of resistivity in ZnO thin films. Due to a high-density carrier accumulation, we have shown the ability to inverse change magnetoresistance in ZnO by ionic liquid gating from 10% to -2.5%. The evolution of photoluminescence under gate voltage was also consistent with the MIT, which is due to the reduction of dislocation. Our in-situ gate-controlled photoluminescence, insulator-metal transition, and the conversion of magnetoresistance open up opportunities in searching for quantum materials and ZnO based photoelectric devices.

  3. The Dynamics of the Electric Field Distribution in the Surface of Insulating Film Irradiated by Air Ions

    Directory of Open Access Journals (Sweden)

    Julionas KALADE

    2016-05-01

    Full Text Available When deposited on a surface, electric charge usually accumulates near the tips of surface irregularities, from where it can be transferred to nearby objects due to ionization of ambient air. The amount of transferred charge, the rate of charge transfer, the size of the charged spot (e.g., on the surface of an insulator and its tendency to spread will depend on properties of air during electric discharge, on the magnitude of charge accumulated at the tip of an object, on possibilities for replenishing that charge, on the time spent for charge transfer from the tip onto the insulating layer, on properties of the insulating layer, etc. Those properties are discussed in this work by comparing the results of measurements and theoretical analysis.

  4. Effect of electric field in the characterization of pultruded GFRP boron-free composite insulator for the extra high voltage by the ionizing radiation

    Energy Technology Data Exchange (ETDEWEB)

    Fujiwara, Hissae; Silva Junior, Edmilson Jose; Shinohara, Armando Hideki [Universidade Federal de Pernambuco (UFPE), Recife, PE (Brazil); Xavier, Gustavo Jose Vasconcelos [CHESF, Recife, PE (Brazil); Costa, Edson Guedes [Universidade Federal de Campina Grande (UFCG), PB (Brazil); Lott Neto, Henrique Batista Duffles Teixeira; Britto, Paulo Roberto Ranzan; Fontan, Marcio A.B. [Sistema de Transmissao do Nordeste S.A., Recife, PE (Brazil)

    2016-07-01

    Full text: The pultruded boron-free glass fiber reinforced polymer (GFRP) composite has been widely used material for the electrical insulators in the high, extra and ultra high voltage overhead lines worldwide. In terms of design, the composite insulator has a highly complex geometry and large size. Aging of materials begin as soon as the insulators start their operation due to the strong electric field, mechanical load due to the weight of conductor cables, environment, corona discharge, generation of acids, and as a result, GFRP can fail mechanically by the stress corrosion crack (SCC) and electrical breakdown known as flashover. In order to mitigate the mechanical and electrical failures, the insulators in the field are frequently monitored by visual inspection, infrared thermography, UV detection, variation of measurement of distribution of electric field variation. However, new technologies for characterization and inspection of the composite insulator in the field are required for reliable operation. Imaging characterization using ionizing radiation (X-ray or g-ray) is an interesting technique, however, it can reduce drastically breakdown voltage due to the Townsend discharge, which free electrons are accelerated by an electric field, collide with gas molecules of air, and free additional electrons resulting in an avalanche multiplication that allows an electrical conduction through the air. In this study, in order to evaluate the potential application of ionization radiation for characterization of composite insulator under electric field, testing were conducted in high voltage laboratory by applying voltages up to 640 kV and varying radiation area of the composite insulator. As a result, even though there was an occurrence of flame on Imaging Plate (IP) detector case when it was located near the phase, corona discharge, but no breakdown discharge (flashover) occurred and high quality imaging of radiography could be obtained when X-ray source was employed

  5. Dark current of organic heterostructure devices with insulating spacer layers

    Science.gov (United States)

    Yin, Sun; Nie, Wanyi; Mohite, Aditya D.; Saxena, Avadh; Smith, Darryl L.; Ruden, P. Paul

    2015-03-01

    The dark current density at fixed voltage bias in donor/acceptor organic planar heterostructure devices can either increase or decrease when an insulating spacer layer is added between the donor and acceptor layers. The dominant current flow process in these systems involves the formation and subsequent recombination of an interfacial exciplex state. If the exciplex formation rate limits current flow, the insulating interface layer can increase dark current whereas, if the exciplex recombination rate limits current flow, the insulating interface layer decreases dark current. We present a device model to describe this behavior and illustrate it experimentally for various donor/acceptor systems, e.g. P3HT/LiF/C60.

  6. First-principles calculation of electric field gradients in metals, semiconductors, and insulators

    Energy Technology Data Exchange (ETDEWEB)

    Zwanziger, J.W. [Dalhousie Univ, Dept Chem, Halifax, NS (Canada); Dalhousie Univ, Inst Res Mat, Halifax, NS (Canada); Torrent, M. [CEA Bruyeres-le-Chatel, Dept Phys Theor and Appl, Bruyeres 91 (France)

    2008-07-01

    A scheme for computing electric field gradients within the projector augmented wave (PAW) formalism of density functional theory is presented. On the basis of earlier work (M. Profeta, F. Mauri, C.J. Pickard, J. Am. Chem. Soc. 125, 541, 2003) the present implementation handles metallic cases as well as insulators and semiconductors with equal efficiency. Details of the implementation, as well as applications and the discussion of the limitations of the PAW method for computing electric field gradients are presented. (authors)

  7. Radiation-resistant plastic insulators

    International Nuclear Information System (INIS)

    Sturm, B.J.; Parkinson, W.W.

    1975-01-01

    A high molecular weight organic composition useful as an electric insulator in radiation fields is provided and comprises normally a solid polymer of an organic compound having a specific resistance greater than 10 19 ohm-cm and containing phenyl groups and 1 to 7.5 weight percent of a high molecular weight organic phosphite. In one embodiment the composition comprises normally solid polystyrene having 7.5 weight percent tris-β-chloroethyl phosphite as an additive; the composition exhibited an increase in the post-irradiation resistivity of over an order of magnitude over the post-irradiation resistivity of pure polystyrene. (Patent Office Record)

  8. Ideology of a multiparametric system for estimating the insulation system of electric machines on the basis of absorption testing methods

    Science.gov (United States)

    Kislyakov, M. A.; Chernov, V. A.; Maksimkin, V. L.; Bozhin, Yu. M.

    2017-12-01

    The article deals with modern methods of monitoring the state and predicting the life of electric machines. In 50% of the cases of failure in the performance of electric machines is associated with insulation damage. As promising, nondestructive methods of control, methods based on the investigation of the processes of polarization occurring in insulating materials are proposed. To improve the accuracy of determining the state of insulation, a multiparametric approach is considered, which is a basis for the development of an expert system for estimating the state of health.

  9. Residual life estimation of electrical insulation system for rotating equipment

    International Nuclear Information System (INIS)

    Vashishtha, Y.D.; Gupta, A.K.; Bhattacharyya, A.K.; Verma, A.K.

    1994-01-01

    Residual life assessment gains significance towards the end of designed life for granting plant life extensions and resource planning for costly equipment replacement. A critical review of all the diagnostic techniques presently used to assess either health of insulation system or to infer qualitatively the remaining life for rotating machines is presented. However more emphasis is required on developing quantitative methods. This paper also formulates the experimental plan for progressively censored ageing tests, measurement of partial discharge parameters, micro-structural study for delamination and electrical tree growth and measurement of electrical breakdown strength. Partial discharge (PD) patterns, electrical tree growth and time to failure data shall be taken as training set for the neural network learning which can be useful to predict residual life with only one candidate parameter i.e. PD patterns. (author). 9 refs

  10. Design Improvements on Graded Insulation of Power Transformers Using Transient Electric Field Analysis and Visualization Technique

    OpenAIRE

    Yamashita, Hideo; Nakamae, Eihachiro; Namera, Akihiro; Cingoski, Vlatko; Kitamura, Hideo

    1998-01-01

    This paper deals with design improvements on graded insulation of power transformers using transient electric field analysis and a visualization technique. The calculation method for transient electric field analysis inside a power transformer impressed with impulse voltage is presented: Initially, the concentrated electric network for the power transformer is concentrated by dividing transformer windings into several blocks and by computing the electric circuit parameters.

  11. Insulator applications in a Tokamak reactor

    International Nuclear Information System (INIS)

    Leger, D.

    1986-06-01

    Insulators, among which insulators ceramics, have great potential applications in fusion reactors. They will be used for all plasma-facing components as protection and, magnetic fusion devices being subject to large electrical currents flowing in any parts of the device, for their electrical insulating properties

  12. Experimental Study on Downwardly Spreading Flame over Inclined Polyethylene-insulated Electrical Wire with Applied AC Electric Fields

    KAUST Repository

    Lim, Seung Jae

    2014-12-30

    An experimental study on downwardly spreading flame over slanted electrical wire, which is insulated by Polyethylene (PE), was conducted with applied AC electric fields. The result showed that the flame spread rate decreased initially with increase in inclination angle of wire and then became nearly constant. The flame shape was modified significantly with applied AC electric field due to the effect of ionic wind. Such a variation in flame spread rate could be explained by a thermal balance mechanism, depending on flame shape and slanted direction of flame. Extinction of the spreading flame was not related to angle of inclination, and was described well by a functional dependency upon the frequency and voltage at extinction.

  13. Experimental study on the effects of AC electric fields on flame spreading over polyethylene-insulated electric-wire

    KAUST Repository

    Jin, Young Kyu

    2010-11-01

    In this present study, we experimentally investigated the effects of electric fields on the characteristics of flames spreading over electric-wires with AC fields. The dependence of the rate at which a flame spreads over polyethylene-insulated wires on the frequency and amplitude of the applied AC electric field was examined. The spreading of the flame can be categorized into linear spreading and non-linearly accelerated spreading of flame. This categorization is based on the axial distribution of the field strength of the applied electric field. The rate at which the flame spreads is highly dependent on the inclined direction of the wire fire. It could be possible to explain the spreading of the flame on the basis of thermal balance. © 2010 The Korean Society of Mechanical Engineers.

  14. Recovery of reactor electrical assemblies using differential de-encapsulation to remove dielectric insulation systems

    International Nuclear Information System (INIS)

    Hubrig, J.G.; Hammerstone, E.B.

    1986-01-01

    State-of-the-art de-encapsulation technologies associated with the conventional dielectric insulation systems employed in the construction of electrical coils and power distribution systems do not allow for accurate fatigue/failure analysis or reliable recovery of costly assembly components. Differential de-encapsulation allows for the selective removal of contemporary thermoset resin based insulation systems to allow non-destructive penetration of insulation wall thicknesses to both examine critical areas and recover high performance metallic and non-metallic inserts for remanufacture; significantly reducing replacement costs and reactor downtime. The authors' analysis describes how the availability of engineering data from the selective and non-destructive removal of insulation materials will aid in the evaluation of original manufacture, materials and procedures; enabling redesign to enhance subsequent on line performance. They also discuss why the ability to recover coil and core assemblies for remanufacture will have a major economic impact on reactor management costs

  15. Effect of resin composition to the electrical and mechanical properties of high voltage insulator material

    International Nuclear Information System (INIS)

    Totok Dermawan; Elin Nuraini; Suyamto

    2012-01-01

    A solid insulator manufacture of resins for high voltage with a variation of resin and hardener composition has been made. The purpose of research to know electrical and mechanical properties of high voltage insulator material of resin. To determine its electric properties, the material is tested its breakdown voltage and the flashover voltage that occurred on the surface. While to determine the mechanical properties were tested by measuring its strength with a tensile test. From testing with variety of mixed composition it is known that for composition between hardener and resin of 1 : 800 has most advantageous properties because it has good strength with a tensile strength of 19.86 MPa and enough high dielectric strength of 43.2 kV / mm). (author)

  16. Electrical insulation characteristics of liquid helium under high speed rotating field

    International Nuclear Information System (INIS)

    Ishii, I.; Fuchino, S.; Okano, M.; Tamada, N.

    1996-01-01

    Electrical breakdown behavior of liquid helium was investigated under high speed rotating field. In the development of superconducting turbine generator it is essential to get the knowledge of electrical insulation characteristics of liquid helium under high speed rotating field. When the current of the field magnet of a superconducting generator is changed, changing magnetic field generates heat in the conductor and it causes bubbles in the liquid helium around the conductor. The behavior of the bubbles is affected largely by the buoyancy which is generated by the centrifugal force. Electrical breakdown behavior of the liquid helium is strongly dependent on the gas bubbles in the liquid. Electrical breakdown voltage between electrodes was measured in a rotating cryostat with and without heater input for bubble formation. Decrease of the breakdown voltage by the heater power was smaller in the rotating field than that in the non rotating field

  17. Top-gate pentacene-based organic field-effect transistor with amorphous rubrene gate insulator

    Science.gov (United States)

    Hiroki, Mizuha; Maeda, Yasutaka; Ohmi, Shun-ichiro

    2018-02-01

    The scaling of organic field-effect transistors (OFETs) is necessary for high-density integration and for this, OFETs with a top-gate configuration are required. There have been several reports of damageless lithography processes for organic semiconductor or insulator layers. However, it is still difficult to fabricate scaled OFETs with a top-gate configuration. In this study, the lift-off process and the device characteristics of the OFETs with a top-gate configuration utilizing an amorphous (α) rubrene gate insulator were investigated. We have confirmed that α-rubrene shows an insulating property, and its extracted linear mobility was 2.5 × 10-2 cm2/(V·s). The gate length and width were 10 and 60 µm, respectively. From these results, the OFET with a top-gate configuration utilizing an α-rubrene gate insulator is promising for the high-density integration of scaled OFETs.

  18. Characterization of ceramic electrical insulators discarded by the electricity distribution networks and compared with similar products without use

    International Nuclear Information System (INIS)

    Franco, C.S.; Mantovani, V.A.; Favero, M.; Morales, J.; Hasegawa, H.L.

    2010-01-01

    The maintenance of distribution networks for electricity generates a large amount of waste. Among these, one of the most representative weights is from porcelain, found in para-rays, braces, insulators. The aim of this study was to evaluate the recycling potential of two models of ceramic insulators, new and used. It had been subjected to comparative tests of scanning electron microscopy, coupled with Energy Dispersive Spectroscopy, x-ray diffraction, contact angle, volatile content and density. In general, samples of new and used ceramic showed no differences that might be associated of material degradation by using. This indicates that the materials discarded and new ones are very close, which may encourage the reuse and recycling. (author)

  19. Effect of thermal insulation on the electrical characteristics of NbOx threshold switches

    Science.gov (United States)

    Wang, Ziwen; Kumar, Suhas; Wong, H.-S. Philip; Nishi, Yoshio

    2018-02-01

    Threshold switches based on niobium oxide (NbOx) are promising candidates as bidirectional selector devices in crossbar memory arrays and building blocks for neuromorphic computing. Here, it is experimentally demonstrated that the electrical characteristics of NbOx threshold switches can be tuned by engineering the thermal insulation. Increasing the thermal insulation by ˜10× is shown to produce ˜7× reduction in threshold current and ˜45% reduction in threshold voltage. The reduced threshold voltage leads to ˜5× reduction in half-selection leakage, which highlights the effectiveness of reducing half-selection leakage of NbOx selectors by engineering the thermal insulation. A thermal feedback model based on Poole-Frenkel conduction in NbOx can explain the experimental results very well, which also serves as a piece of strong evidence supporting the validity of the Poole-Frenkel based mechanism in NbOx threshold switches.

  20. Forming Refractory Insulation On Copper Wire

    Science.gov (United States)

    Setlock, J.; Roberts, G.

    1995-01-01

    Alternative insulating process forms flexible coat of uncured refractory insulating material on copper wire. Coated wire formed into coil or other complex shape. Wire-coating apparatus forms "green" coat on copper wire. After wire coiled, heating converts "green" coat to refractory electrical insulator. When cured to final brittle form, insulating material withstands temperatures above melting temperature of wire. Process used to make coils for motors, solenoids, and other electrical devices to be operated at high temperatures.

  1. Improved model of activation energy absorption for different electrical breakdowns in semi-crystalline insulating polymers

    Science.gov (United States)

    Sima, Wenxia; Jiang, Xiongwei; Peng, Qingjun; Sun, Potao

    2018-05-01

    Electrical breakdown is an important physical phenomenon in electrical equipment and electronic devices. Many related models and theories of electrical breakdown have been proposed. However, a widely recognized understanding on the following phenomenon is still lacking: impulse breakdown strength which varies with waveform parameters, decrease in the breakdown strength of AC voltage with increasing frequency, and higher impulse breakdown strength than that of AC. In this work, an improved model of activation energy absorption for different electrical breakdowns in semi-crystalline insulating polymers is proposed based on the Harmonic oscillator model. Simulation and experimental results show that, the energy of trapped charges obtained from AC stress is higher than that of impulse voltage, and the absorbed activation energy increases with the increase in the electric field frequency. Meanwhile, the frequency-dependent relative dielectric constant ε r and dielectric loss tanδ also affect the absorption of activation energy. The absorbed activation energy and modified trap level synergistically determine the breakdown strength. The mechanism analysis of breakdown strength under various voltage waveforms is consistent with the experimental results. Therefore, the proposed model of activation energy absorption in the present work may provide a new possible method for analyzing and explaining the breakdown phenomenon in semi-crystalline insulating polymers.

  2. NAA of an egyptian ceramic electric insulator sample

    International Nuclear Information System (INIS)

    ASHMAWY, L.S.; EISSA, E.A.; ROFAIL, N.B.; HASSAN, A.M.

    2000-01-01

    In this work a sample of a ceramic electric insulator material used in Egypt in the production of transformers and indoor electric equipment has been elementally analyzed by Neutron Activation Analysis (NAA) technique. The Pneumatic Rabbit Transfer System (PRTS) of the 10 MW Budapest Research Reactor (BRR) was used, for short time irradiation of 120 s. Long time irradiation was performed at the reactor core periphery for 24 hours, The thermal neutron fluxes at full reactor power in both cases were 6 x 1013 n/cm 2.s and 3 x 1013 n/cm 2 .s, respectively. The gamma-ray spectra obtained have been measured for several times by means of the Hyper Pure Germanium Detection System (HPGe). The ko computer programs were used for data analysis. A total of 42 elements have been identified as: Na, Al, Cl, K, Sc, Ti, V, Mn, Fe, Co, Zn, Ga, As, Br, Rb, Sr, Zr, Mo, Ag, Sb, Te, Cs, Ba, La, Ce, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Tm, Yb, Lu, Hf, Ta, W, Ir, Au, Th and U

  3. Formation of electrically insulating coatings on aluminided vanadium-base alloys in liquid lithium

    International Nuclear Information System (INIS)

    Park, J.H.; Dragel, G.

    1993-01-01

    Aluminide coatings were produced on vanadium and vanadium-base alloys by exposure of the materials to liquid lithium that contained 3-5 at.% dissolved aluminum in sealed capsules at temperatures between 775 and 880 degrees C. Reaction of the aluminide layer with dissolved nitrogen in liquid lithium provides a means of developing an in-situ electrical insulator coating on the surface of the alloys. The electrical resistivity of A1N coatings on aluminided V and V-20 wt.% Ti was determined in-situ

  4. Assessment of Eco-friendly Gases for Electrical Insulation to Replace the Most Potent Industrial Greenhouse Gas SF6.

    Science.gov (United States)

    Rabie, Mohamed; Franck, Christian M

    2018-01-16

    Gases for electrical insulation are essential for the operation of electric power equipment. This Review gives a brief history of gaseous insulation that involved the emergence of the most potent industrial greenhouse gas known today, namely sulfur hexafluoride. SF 6 paved the way to space-saving equipment for the transmission and distribution of electrical energy. Its ever-rising usage in the electrical grid also played a decisive role in the continuous increase of atmospheric SF 6 abundance over the last decades. This Review broadly covers the environmental concerns related to SF 6 emissions and assesses the latest generation of eco-friendly replacement gases. They offer great potential for reducing greenhouse gas emissions from electrical equipment but at the same time involve technical trade-offs. The rumors of one or the other being superior seem premature, in particular because of the lack of dielectric, environmental, and chemical information for these relatively novel compounds and their dissociation products during operation.

  5. Relationship of Cure Temperature to Mechanical, Physical, and Dielectric Performance of PDMS Glass Composite for Electric Motor Insulation

    Science.gov (United States)

    Miller, Sandi G.; Becker, Kathleen; Williams, Tiffany S.; Scheiman, Daniel A.; McCorkle, Linda S.; Heimann, Paula J.; Ring, Andrew; Woodworth, Andrew

    2017-01-01

    Achieving NASAs aggressive fuel burn and emission reduction for N-plus-3 aircraft will require hybrid electric propulsion system in which electric motors driven by either power generated from turbine or energy storage system will power the fan for propulsion. Motors designed for hybrid electric aircraft are expected to operate at medium to high voltages over long durations in a high altitude service environment. Such conditions have driven research toward the development of wire insulation with improved mechanical strength, thermal stability and increased breakdown voltage. The silicone class of materials has been considered for electric wire insulation due to its inherent thermal stability, dielectric strength and mechanical integrity. This paper evaluates the dependence of these properties on the cure conditions of a polydimethyl-siloxane (PDMS) elastomer; where both cure temperature and base-to-catalyst ratio were varied. The PDMS elastomer was evaluated as a bulk material and an impregnation matrix within a lightweight glass veil support. The E-glass support was selected for mechanical stiffness and dielectric strength. This work has shown a correlation between cure conditions and material physical properties. Tensile strength increased with cure temperature whereas breakdown voltage tended to be independent of process variations. The results will be used to direct material formulation based on specific insulation requirements.

  6. Review of Research Progress on the Electrical Properties and Modification of Mineral Insulating Oils Used in Power Transformers

    Directory of Open Access Journals (Sweden)

    Xiaobo Wang

    2018-02-01

    Full Text Available In November 2017, the first ±1100 kV high-voltage direct-current power transformer in the world, which was made by Siemens in Nurnberg, passed its type test. Meanwhile, in early 2017, a ±1000 kV ultra-high voltage (UHV substation was officially put into operation in Tianjin, China. These examples illustrate that the era of UHV power transmission is coming. With the rapid increase in power transmission voltage, the performance requirements for the insulation of power transformers are getting higher and higher. The traditional mineral oils used inside power transformers as insulating and cooling agents are thus facing a serious challenge to meet these requirements. In this review, the basic properties of traditional mineral insulating oil are first introduced. Then, the variation of electrical properties such as breakdown strength, permittivity, and conductivity during transformer operation and aging is summarized. Next, the modification of mineral insulating oil is investigated with a focus on the influence of nanoparticles on the electrical properties of nano-modified insulating oil. Recent studies on the performance of mineral oil at molecular and atomic levels by molecular dynamics simulations are then described. Finally, future research hotspots and notable research topics are discussed.

  7. Processing and performance of organic insulators as a gate layer in ...

    Indian Academy of Sciences (India)

    Abstract. Fabrication of organic thin film transistor (OTFT) on flexible substrates is a challenge, because of its low softening temperature, high roughness and flexible nature. Although several organic dielectrics have been used as gate insulator, it is difficult to choose one in absence of a comparative study covering ...

  8. Organic insulators and the copper stabilizer for fusion-reactor magnets

    International Nuclear Information System (INIS)

    Coltman, R.R. Jr.

    1981-11-01

    The materials which compose the large composite superconducting fusion reactor magnets are subjected to mechanical stress, neutron and gamma-ray radiation with broad energy spectra, high magnetic fields, and thermal cycling from 4 to 300 K. Of the materials now considered for use in the magnets, results show that the organic insulators and the Cu stabilizer are the most sensitive to this environment. In response to the need for stabilizer data, magnetoresistivity changes were studied in eight variously prepared specimens of Cu throughout five cycles of an alternate neutron irradiation (4.0 K) and annealing (14 h at 307 K) program. The results were combined with those on the radiation behavior of epoxy and polyimide organic insulators to provide a preliminary assessment of their comparative radiation resistance in a typical magnet location of the Experimental Power Reactor

  9. Low-voltage organic field-effect transistors based on novel high-κ organometallic lanthanide complex for gate insulating materials

    Directory of Open Access Journals (Sweden)

    Qi Liu

    2014-08-01

    Full Text Available A novel high-κ organometallic lanthanide complex, Eu(tta3L (tta=2-thenoyltrifluoroacetonate, L = 4,5-pinene bipyridine, is used as gate insulating material to fabricate low-voltage pentacene field-effect transistors (FETs. The optimized gate insulator exhibits the excellent properties such as low leakage current density, low surface roughness, and high dielectric constant. When operated under a low voltage of −5 V, the pentacene FET devices show the attractive electrical performance, e.g. carrier mobility (μFET of 0.17 cm2 V−1 s−1, threshold voltage (Vth of −0.9 V, on/off current ratio of 5 × 103, and subthreshold slope (SS of 1.0 V dec−1, which is much better than that of devices obtained on conventional 300 nm SiO2 substrate (0.13 cm2 V−1 s−1, −7.3 V and 3.1 V dec−1 for μFET, Vth and SS value when operated at −30 V. These results indicate that this kind of high-κ organometallic lanthanide complex becomes a promising candidate as gate insulator for low-voltage organic FETs.

  10. Processing and performance of organic insulators as a gate layer in ...

    Indian Academy of Sciences (India)

    Fabrication of organic thin film transistor (OTFT) on flexible substrates is a challenge, because of its low softening temperature, high roughness and flexible nature. Although several organic dielectrics have been used as gate insulator, it is difficult to choose one in absence of a comparative study covering processing of ...

  11. The Development and Application of Simulative Insulation Resistance Tester

    Science.gov (United States)

    Jia, Yan; Chai, Ziqi; Wang, Bo; Ma, Hao

    2018-02-01

    The insulation state determines the performance and insulation life of electrical equipment, so it has to be judged in a timely and accurate manner. Insulation resistance test, as the simplest and most basic test of high voltage electric tests, can measure the insulation resistance and absorption ratio which are effective criterion of part or whole damp or dirty, breakdown, severe overheating aging and other insulation defects. It means that the electrical test personnel need to be familiar with the principle of insulation resistance test, and able to operate the insulation resistance tester correctly. At present, like the insulation resistance test, most of electrical tests are trained by physical devices with the real high voltage. Although this allows the students to truly experience the test process and notes on security, it also has certain limitations in terms of safety and test efficiency, especially for a large number of new staves needing induction training every year. This paper presents a new kind of electrical test training system based on the simulative device of dielectric loss measurement and simulative electrical testing devices. It can not only overcome the defects of current training methods, but also provide other advantages in economical efficiency and scalability. That makes it possible for the system to be allied in widespread.

  12. Electrical insulation for large multiaxis superconducting magnets

    International Nuclear Information System (INIS)

    Harvey, A.R.; Rinde, J.A.

    1975-01-01

    The selection of interturn and interlayer insulation for superconducting magnets is discussed. The magnet problems of the Baseball II device are described. Manufacture of the insulation and radiation damage are mentioned. A planned experimental program is outlined

  13. Effect of artificial aging on polymeric surge arresters and polymer insulators for electricity distribution networks

    Directory of Open Access Journals (Sweden)

    Carlos A. Ferreira

    2011-01-01

    Full Text Available A study was conducted to evaluate new and laboratory-aged samples of surge arresters and anchorage polymeric insulators, for 12 and 24 kV networks, which are used by the Rio Grande Energia (RGE. Power Utility Polymeric compounds were analyzed by Differential Scanning Calorimetry (DSC, Thermogravimetric Analysis (TG, Dynamic-Mechanic Analysis (DMA, Fourier Transformed Infrared Spectroscopy (FTIR and Scanning Electronic Microscopy (SEM to verify changes in the insulator properties due to degradation occurred during the experiments. The analyses were carried out before and after 6 months of aging in laboratory devices (weatherometer, 120 °C, salt spray, immersion in water. After the aging experiments, high-voltage electrical tests were also conducted: a radio interference voltage test and, simultaneously, the total and the internal leakage currents were measured to verify the surface degradation of the polymeric material used in the housing. The impulse current test was applied with current values close to 5, 10 and 30 kA, in order to force an internal degradation. Results showed that only surface degradation is detected at the polymer. The main properties of the parts were not affected by the aging. It confirms that polymer insulator and surge arrestor are appropriate for use in electricity distribution networks.

  14. Effect of artificial aging on polymeric surge arresters and polymer insulators for electricity distribution networks

    Energy Technology Data Exchange (ETDEWEB)

    Ferreira, Carlos A.; Coser, E. [Laboratorio de Materiais Polimericos, Departamento de Engenharia de Materiais, Universidade Federal do Rio Grande do Sul, Porto Alegre, RS (Brazil)], e-mail: ferreira.carlos@ufrgs.br; Angelini, Joceli M.G. [Departamento de Materiais Eletricos, CPqD, Campinas, SP (Brazil); Rossi, Jose A.D. [Materiais Alta Tensao, CPqD, Campinas, SP (Brazil); Martinez, Manuel L.B. [Departamento de Engenharia Eletrica, UNIFEI, Itajuba, MG (Brazil)

    2011-07-01

    A study was conducted to evaluate new and laboratory-aged samples of surge arresters and anchorage polymeric insulators, for 12 and 24 kV networks, which are used by the Rio Grande Energia (RGE). Power utility polymeric compounds were analyzed by Differential Scanning Calorimetry (DSC), Thermogravimetric Analysis (TG), Dynamic-Mechanic Analysis (DMA), Fourier Transformed Infrared Spectroscopy (FTIR) and Scanning Electronic Microscopy (SEM) to verify changes in the insulator properties due to degradation occurred during the experiments. The analyses were carried out before and after 6 months of aging in laboratory devices (weather meter, 120 deg C, salt spray, immersion in water). After the aging experiments, high-voltage electrical tests were also conducted: a radio interference voltage test and, simultaneously, the total and the internal leakage currents were measured to verify the surface degradation of the polymeric material used in the housing. The impulse current test was applied with current values close to 5, 10 and 30 k A, in order to force an internal degradation. Results showed that only surface degradation is detected at the polymer. The main properties of the parts were not affected by the aging. It confirms that polymer insulator and surge arrester are appropriate for use in electricity distribution networks. (author)

  15. Complex studies of mockups of electric insulators of cryoresistive coils of the T-15 device electromagnet system

    International Nuclear Information System (INIS)

    Aksenov, O.E.; Gringof, V.G.; Il'in, G.V.; Lapenas, A.A.; Stepanov, A.N.; Ulmanis, U.A.

    1982-01-01

    The test results are presented for multilayer electrical insulation of coils in the T-15 thermonuclear device electromagnet system. The insulation is made ion the base of polyimide tape with adhesive coating. In the 77-93 K range the tape insulating strength is 35 MV/m, the dielectric loss tangent is less than 10 -5 , dielectric permeability is 2.5, volume resistivity is more than 10 5 Ohmxcm. The insulation has been tested for radiation effects in the IRT-2000 nuclear reactor. Different batches of insulation mockups 0.7 mm thick have been irradiated up to the integral fast neutron flux within the 10 16 -5x10 18 neutr./cm 2 range (E >= 0.1 MeV), (J=10 11 -10 12 neutr./cm 2 xs) at the corresponding temperature between 390 and 420 K. The given data on insulating strength point to a high radiation resistance of the multilayer polyimide insulation. To make sure finally that the developed insulation system meets the requirements of the operating conditions for thermonuclear device electromagnet system coils the device has been tested for operational life. On the basis of the test results a conclusion can be made that at the present development stage the multilayer polyimide insulation based on the adhesive tape meets to the utmost degree the requirements corresponding to the complicated operating conditions of the T-15 thermonuclear devices

  16. Advanced-fueled fusion reactors suitable for direct energy conversion. Project note: temperature-gradient enhancement of electrical fields in insulators

    International Nuclear Information System (INIS)

    Blum, A.S.; Mancebo, L.

    1976-01-01

    Direct energy converters for use on controlled fusion reactors utilize electrodes operated at elevated voltages and temperatures. The insulating elements that position these electrodes must support large voltages and under some circumstances large thermal gradients. It is shown that even modest thermal gradients can cause major alterations of the electric-field distribution within the insulating element

  17. Stability of polarization in organic ferroelectric metal-insulator-semiconductor (MIS) structures

    Energy Technology Data Exchange (ETDEWEB)

    Kalbitz, Rene; Fruebing, Peter; Gerhard, Reimund [Department of Physics and Astronomy, University of Potsdam, Karl-Liebknecht-Strasse 24-25, 14476, Potsdam (Germany); Taylor, Martin [School of Electronic Engineering, Bangor University, Dean Street, Bangor Gwynedd, LL57 1UT (United Kingdom)

    2011-07-01

    Ferroelectric field effect transistors (FeFETs) offer the prospect of an organic-based memory device. Since the charge transport in such devices is confined to the interface between the insulator and the semiconductor, the focus of the present study was on the investigation of this region. Capacitance-voltage (C-V) measurements of all-organic MIS devices with poly(vinylidenefluoride- trifluoroethylene) (P(VDF-TrFE)) as gate insulator and poly(3-hexylthiophene)(P3HT) as semiconductor were carried out. When the structure was driven into depletion, a positive flat-band voltage shift was observed arising from the change in polarization state of the ferroelectric insulator. When driven into accumulation, the polarization was reversed. It is shown that both polarization states are stable. However, negative charge trapped at the interface during the depletion cycle masks the negative shift in flat-band voltage expected during the sweep to accumulation voltages. Measurements on P(VDF-TrFE)/P3HT based FeFETs yield further evidence for fixed charges at the interface. Output characteristics suggest the injection of negative charges into the interface region when a depletion voltage is applied between source and gate contact.

  18. Electric controlling of surface metal-insulator transition in the doped BaTiO3 film

    Directory of Open Access Journals (Sweden)

    Wei Xun

    2017-07-01

    Full Text Available Based on first-principles calculations, the BaTiO3(BTO film with local La-doping is studied. For a selected concentration and position of doping, the surface metal-insulator transition occurs under the applied electric field, and the domain appears near the surface for both bipolar states. Furthermore, for the insulated surface state, i.e., the downward polarization state in the doped film, the gradient bandgap structure is achieved, which favors the absorption of solar energy. Our investigation can provide an alternative avenue in modification of surface property and surface screening effect in polar materials.

  19. Carrier transport in flexible organic bistable devices of ZnO nanoparticles embedded in an insulating poly(methyl methacrylate) polymer layer

    International Nuclear Information System (INIS)

    Son, Dong-Ick; Park, Dong-Hee; Choi, Won Kook; Cho, Sung-Hwan; Kim, Won-Tae; Kim, Tae Whan

    2009-01-01

    The bistable effects of ZnO nanoparticles embedded in an insulating poly(methyl methacrylate) (PMMA) polymer single layer by using flexible polyethylene terephthalate (PET) substrates were investigated. Transmission electron microscopy (TEM) images revealed that ZnO nanoparticles were formed inside the PMMA polymer layer. Current-voltage (I-V) measurement on the Al/ZnO nanoparticles embedded in an insulating PMMA polymer layer/ITO/PET structures at 300 K showed a nonvolatile electrical bistability behavior with a flat-band voltage shift due to the existence of the ZnO nanoparticles, indicative of trapping, storing, and emission of charges in the electronic states of the ZnO nanoparticles. The carrier transport mechanism of the bistable behavior for the fabricated organic bistable device (OBD) structures is described on the basis of the I-V results by analyzing the effect of space charge.

  20. Insulation systems for superconducting transmission cables

    DEFF Research Database (Denmark)

    Tønnesen, Ole

    1996-01-01

    the electrical insulation is placed outside both the superconducting tube and the cryostat. The superconducting tube is cooled by liquid nitrogen which is pumped through the hollow part of the tube.2) The cryogenic dielectric design, where the electrical insulation is placed inside the cryostat and thus is kept...

  1. Electrical and mechanical properties of highly elongated high density polyethylene as cryogenic insulation materials

    International Nuclear Information System (INIS)

    Yoshino, Katsumi; Park, Dae-Hee; Miyata, Kiyomi; Yamaoka, Hitoshi; Itoh, Minoru; Ichihara, Syouji.

    1989-01-01

    Electrical and mechanical properties of highly elongated high density polyethylene were investigated in the temperature range between 4.2 K and 400 K from a viewpoint of electrical insulation at low temperature and the following properties have been clarified. (1) The electrical conductivity of samples decreases with increasing draw ratio, and also decreases at cryogenic temperature. (2) Breakdown strength of highly elongated sample is similar to that of non-elongated sample. It is nearby temperature independent below 300 K but at higher temperature it falls steeply. (3) Mechanical breakdown stress and elastic modulus of high density polyethylene increase with increasing draw ratio. Their values at liquid nitrogen temperature are much higher than that at room temperature. On the other hand, strains decreases at liquid nitrogen temperature. (4) Break of the sample develops in the direction of 45deg from the direction of stress both at room temperature and at cryogenic temperature. (5) The characteristic of mechanical breakdown at liquid nitrogen temperature can be explained by a brittleness fracture process. (6) Toughness of high density polyethylene increases with increasing draw ratio until draw ratio of 5, and it decreased, and increase at higher draw ratio. However at extremely high draw ratio of 10 it again increases. These findings clearly indicate that highly elongated high density polyethylene has good electrical and mechanical properties at cryogenic temperature and can be used as the insulating materials at cryogenic temperature. (author)

  2. Low dielectric constant-based organic field-effect transistors and metal-insulator-semiconductor capacitors

    Science.gov (United States)

    Ukah, Ndubuisi Benjamin

    This thesis describes a study of PFB and pentacene-based organic field-effect transistors (OFET) and metal-insulator-semiconductor (MIS) capacitors with low dielectric constant (k) poly(methyl methacrylate) (PMMA), poly(4-vinyl phenol) (PVP) and cross-linked PVP (c-PVP) gate dielectrics. A physical method -- matrix assisted pulsed laser evaporation (MAPLE) -- of fabricating all-polymer field-effect transistors and MIS capacitors that circumvents inherent polymer dissolution and solvent-selectivity problems, is demonstrated. Pentacene-based OFETs incorporating PMMA and PVP gate dielectrics usually have high operating voltages related to the thickness of the dielectric layer. Reduced PMMA layer thickness (≤ 70 nm) was obtained by dissolving the PMMA in propylene carbonate (PC). The resulting pentacene-based transistors exhibited very low operating voltage (below -3 V), minimal hysteresis in their transfer characteristics, and decent electrical performance. Also low voltage (within -2 V) operation using thin (≤ 80 nm) low-k and hydrophilic PVP and c-PVP dielectric layers obtained via dissolution in high dipole moment and high-k solvents -- PC and dimethyl sulfoxide (DMSO), is demonstrated to be a robust means of achieving improved electrical characteristics and high operational stability in OFETs incorporating PVP and c-PVP dielectrics.

  3. High-performance insulator structures for accelerator applications

    International Nuclear Information System (INIS)

    Sampayan, S.E.; Caporaso, G.J.; Sanders, D.M.; Stoddard, R.D.; Trimble, D.O.; Elizondo, J.; Krogh, M.L.; Wieskamp, T.F.

    1997-05-01

    A new, high gradient insulator technology has been developed for accelerator systems. The concept involves the use of alternating layers of conductors and insulators with periods of order 1 mm or less. These structures perform many times better (about 1.5 to 4 times higher breakdown electric field) than conventional insulators in long pulse, short pulse, and alternating polarity applications. We describe our ongoing studies investigating the degradation of the breakdown electric field resulting from alternate fabrication techniques, the effect of gas pressure, the effect of the insulator-to-electrode interface gap spacing, and the performance of the insulator structure under bi-polar stress

  4. Radiation cross-linking of small electrical wire insulator fabricated from NR/LDPE blends

    Energy Technology Data Exchange (ETDEWEB)

    Siri-Upathum, Chyagrit [Department of Nuclear Technology, Faculty of Engineering Chulalongkorn University, Bangkok 10330 (Thailand)], E-mail: chyagrit@chula.ac.th; Punnachaiya, Suvit [Department of Nuclear Technology, Faculty of Engineering Chulalongkorn University, Bangkok 10330 (Thailand)

    2007-12-15

    A low voltage, radiation-crosslinked wire insulator has been fabricated from blends of natural rubber block (STR-5L) and LDPE with phthalic anhydride (PA) as a compatibilizer. Physical properties of the NR/LDPE blend ratios of 50/50 and 60/40 with 0.5, 1.0, and 1.5 wt% PA were evaluated. The gel content increased as the radiation dose increased. Tensile at break exhibited a maximum value of 12 MPa at 120 kGy for 1.0 and 1.5 wt% PA of both blend ratios. A higher PA content yielded a higher modulus for the same blend ratio. Blends of 60/40 ratio with 1.0 wt% PA and 0.8 wt% antimony oxide flame retardant gave the highest limiting oxygen index (LOI) of >30% at above 150 kGy. Other electrical properties of the wire insulator were investigated. It was found that an insulator fabricated from a PA content of 1.0 wt% in the NR/LDPE blend ratio of 50/50, after gamma ray cross-linked at a dose of 180 kGy in low vacuum (1 mm Hg), met the Thai Industrial Standard 11-2531 for low voltage wire below 1.0 kV. To comply with the standard for vertical flame test, a more suitable flame retardant was needed for the insulator.

  5. Low-voltage organic field-effect transistors based on novel high-κ organometallic lanthanide complex for gate insulating materials

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Qi; Li, Yi; Zhang, Yang; Song, You, E-mail: wangxzh@nju.edu.cn, E-mail: yli@nju.edu.cn, E-mail: yousong@nju.edu.cn; Wang, Xizhang, E-mail: wangxzh@nju.edu.cn, E-mail: yli@nju.edu.cn, E-mail: yousong@nju.edu.cn; Hu, Zheng [Key Laboratory of Mesoscopic Chemistry of MOE, Jiangsu Provincial Lab for Nanotechnology, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing 210093, China. High-Tech Research Institute of Nanjing University (Suzhou), Suzhou 215123 (China); Sun, Huabin; Li, Yun, E-mail: wangxzh@nju.edu.cn, E-mail: yli@nju.edu.cn, E-mail: yousong@nju.edu.cn; Shi, Yi [School of Electronic Science and Engineering and Jiangsu Provincial Key Laboratory of Photonic and Electronic Materials, Nanjing University, Nanjing 210093 (China)

    2014-08-15

    A novel high-κ organometallic lanthanide complex, Eu(tta){sub 3}L (tta=2-thenoyltrifluoroacetonate, L = 4,5-pinene bipyridine), is used as gate insulating material to fabricate low-voltage pentacene field-effect transistors (FETs). The optimized gate insulator exhibits the excellent properties such as low leakage current density, low surface roughness, and high dielectric constant. When operated under a low voltage of −5 V, the pentacene FET devices show the attractive electrical performance, e.g. carrier mobility (μ{sub FET}) of 0.17 cm{sup 2} V{sup −1} s{sup −1}, threshold voltage (V{sub th}) of −0.9 V, on/off current ratio of 5 × 10{sup 3}, and subthreshold slope (SS) of 1.0 V dec{sup −1}, which is much better than that of devices obtained on conventional 300 nm SiO{sub 2} substrate (0.13 cm{sup 2} V{sup −1} s{sup −1}, −7.3 V and 3.1 V dec{sup −1} for μ{sub FET}, V{sub th} and SS value when operated at −30 V). These results indicate that this kind of high-κ organometallic lanthanide complex becomes a promising candidate as gate insulator for low-voltage organic FETs.

  6. Radiation effects on organic insulators for superconducting magnets. Annual progress report for period ending September 30, 1979

    International Nuclear Information System (INIS)

    Coltman, R.R. Jr.; Klabunde, C.E.; Kernohan, R.H.; Long, C.J.

    1979-11-01

    The most recent efforts in a program to study the effects of irradiation near 5 K on organic insulators for fusion reactors have extended the irradiation dose from 2 x 10 9 to 1 x 10 10 rads and have studied additional effects due to fast neutrons. When added to a gamma-ray dose of 2.4 x 10 9 rads, a fast-neutron fluence of 2.4 x 10 20 n/m 2 has little effect upon changes in electrical and mechanical properties. At this dose, present results are in agreement with previous results. At a dose of 1 x 10 10 rads, particle-filled epoxies are at end of life in terms of mechanical strength, while fiberglass-cloth-filled epoxies retain sufficient strength for use. Electrical-resistivity and voltage-breakdown values were reduced in some materials but remained in a usable range. Two sheet-type materials showed excellent stability in their electrical properties. Dimensional stability was generally good, except for one epoxy which showed considerable swelling at the higher dose

  7. Research on vacuum insulation for cryocables

    International Nuclear Information System (INIS)

    Graneau, P.

    1974-01-01

    Vacuum insulation, as compared with solid insulation, simplifies the construction of both resistive or superconducting cryogenic cables. The common vacuum space in the cable can furnish thermal insulation between the environment and the cryogenic coolant, provide electrical insulation between conductors, and establish thermal isolation between go- and return-coolant streams. The differences between solid and vacuum high voltage insulation are discussed, and research on the design, materials selection, and testing of vacuum insulated cryogenic cables is described

  8. Electric field-triggered metal-insulator transition resistive switching of bilayered multiphasic VOx

    Science.gov (United States)

    Won, Seokjae; Lee, Sang Yeon; Hwang, Jungyeon; Park, Jucheol; Seo, Hyungtak

    2018-01-01

    Electric field-triggered Mott transition of VO2 for next-generation memory devices with sharp and fast resistance-switching response is considered to be ideal but the formation of single-phase VO2 by common deposition techniques is very challenging. Here, VOx films with a VO2-dominant phase for a Mott transition-based metal-insulator transition (MIT) switching device were successfully fabricated by the combined process of RF magnetron sputtering of V metal and subsequent O2 annealing to form. By performing various material characterizations, including scanning transmission electron microscopy-electron energy loss spectroscopy, the film is determined to have a bilayer structure consisting of a VO2-rich bottom layer acting as the Mott transition switching layer and a V2O5/V2O3 mixed top layer acting as a control layer that suppresses any stray leakage current and improves cyclic performance. This bilayer structure enables excellent electric field-triggered Mott transition-based resistive switching of Pt-VOx-Pt metal-insulator-metal devices with a set/reset current ratio reaching 200, set/reset voltage of less than 2.5 V, and very stable DC cyclic switching upto 120 cycles with a great set/reset current and voltage distribution less than 5% of standard deviation at room temperature, which are specifications applicable for neuromorphic or memory device applications. [Figure not available: see fulltext.

  9. Survival of the insulator under the electrical stress condition at cryogenic temperature

    Energy Technology Data Exchange (ETDEWEB)

    Baek, Seung Myeong [Dept. of Fire Protection Engineering, Changwon Moonsung University, Changwon (Korea, Republic of); Kim, Sang Hyun [Dept. of Electrical Engineering, Gyeongsang National University, Jinju (Korea, Republic of)

    2013-12-15

    We have clearly investigated with respect to the survival of the insulator at cryogenic temperature under the electrical stress. The breakdown and voltage-time characteristics of turn-to-turn models for point contact geometry and surface contact geometry using copper multi wrapped with polyimide film for an HTS transformer were investigated under AC and impulse voltage at 77 K. Polyimide film (Kapton) 0.025 mm thick is used for multi wrapping of the electrode. As expected, the breakdown voltages for the surface contact geometry are lower than that of the point contact geometry, because the contact area of the surface contact geometry is lager than that of the point contact geometry. The time to breakdown t50 decreases as the applied voltage is increased, and the lifetime indices increase slightly as the number of layers is increased. The electric field amplitude at the position where breakdown occurs is about 80% of the maximum electric field value. The relationship between survival probability and the electrical stress at cryogenic temperature was evident.

  10. New mechanism of semiconductor polarization at the interface with an organic insulator

    International Nuclear Information System (INIS)

    Yafyasov, A. M.; Bogevolnov, V. B.; Ryumtsev, E. I.; Kovshik, A. P.; Mikhailovski, V. Yu.

    2017-01-01

    A semiconductor—organic-insulator system with spatially distributed charge is created with a uniquely low density of fast surface states (N_s_s) at the interface. A system with N_s_s ≈ 5 × 10"1"0 cm"–"2 is obtained for the example of n-Ge and the physical characteristics of the interface are measured for this system with liquid and metal field electrodes. For a system with an organic insulator, the range of variation of the surface potential from enrichment of the space-charge region of the semiconductor to the inversion state is first obtained without changing the mechanism of interaction between the adsorbed layer and the semiconductor surface. The effect of enhanced polarization of the space-charge region of the semiconductor occurs due to a change in the spatial structure of mobile charge in the organic dielectric layer. The system developed in the study opens up technological opportunities for the formation of a new generation of electronic devices based on organic film structures and for experimental modeling of the electronic properties of biological membranes.

  11. New mechanism of semiconductor polarization at the interface with an organic insulator

    Energy Technology Data Exchange (ETDEWEB)

    Yafyasov, A. M., E-mail: yafyasov@gmail.com; Bogevolnov, V. B.; Ryumtsev, E. I.; Kovshik, A. P. [St. Petersburg State University (Russian Federation); Mikhailovski, V. Yu. [Interdisciplinary Resource Center for Nanotechnology at St. Petersburg University (Russian Federation)

    2017-02-15

    A semiconductor—organic-insulator system with spatially distributed charge is created with a uniquely low density of fast surface states (N{sub ss}) at the interface. A system with N{sub ss} ≈ 5 × 10{sup 10} cm{sup –2} is obtained for the example of n-Ge and the physical characteristics of the interface are measured for this system with liquid and metal field electrodes. For a system with an organic insulator, the range of variation of the surface potential from enrichment of the space-charge region of the semiconductor to the inversion state is first obtained without changing the mechanism of interaction between the adsorbed layer and the semiconductor surface. The effect of enhanced polarization of the space-charge region of the semiconductor occurs due to a change in the spatial structure of mobile charge in the organic dielectric layer. The system developed in the study opens up technological opportunities for the formation of a new generation of electronic devices based on organic film structures and for experimental modeling of the electronic properties of biological membranes.

  12. An effect of heat insulation parameters on thermal losses of water-cooled roofs for secondary steelmaking electric arc furnaces

    Directory of Open Access Journals (Sweden)

    E. Mihailov

    2016-07-01

    Full Text Available The aim of this work is research in the insulation parameters effect on the thermal losses of watercooled roofs for secondary steelmaking electric arc furnaces. An analytical method has been used for the investigation in heat transfer conditions in the working area. The results of the research can be used to choose optimal cooling parameters and select a suitable kind of insulation for water-cooled surfaces.

  13. Theory of the electric current transmission coefficient in the superconductor-insulator-superconductor geometry

    International Nuclear Information System (INIS)

    Navani, R.

    1974-01-01

    Tunneling in the superconductor-insulator-superconductor (S'-I-S) geometry, where the two superconductors are not necessarily the same, is studied theoretically. Two different models of the S'-I-S geometry - which we call the ''initial model'' and the ''improved model'' are discussed. For the initial model the potential barrier is flat. In the improved model, however, the differing material properties of the three regions - S', I, and S - are taken into account in an approximate fashion. In addition, applied, contact, and image potentials in the insulator are included. The solid state material properties that are taken to be different are the effective electronic masses in the three regions and the Fermi energies in the two superconductors. The quasiparticle wave functions in the S', I, and S regions are determined for both models as solutions to the Bogoliubov-de Gennes equations. The electric current transmission coefficients (also the reflection coefficient for the initial model) are derived and their behavior is extensively analyzed. Their forms in the thick barrier limit - where L greater than or approximately equal to 5 A - are related to the BCS densities of states. The tunneling current density is found to depend strongly on the tunneling angle. A relation between the angular position of the tunneling current peak and the barrier thickness is given. Finally, it is shown that the choice of insulator material effects the tunneling current, and the effect is greater the thicker the insulating film

  14. Thermally conductive, electrically insulating and melt-processable polystyrene/boron nitride nanocomposites prepared by in situ reversible addition fragmentation chain transfer polymerization

    International Nuclear Information System (INIS)

    Huang, Xingyi; Wang, Shen; Zhu, Ming; Yang, Ke; Jiang, Pingkai; Bando, Yoshio; Golberg, Dmitri; Zhi, Chunyi

    2015-01-01

    Thermally conductive and electrically insulating polymer/boron nitride (BN) nanocomposites are highly attractive for various applications in many thermal management fields. However, so far most of the preparation methods for polymer/BN nanocomposites have usually caused difficulties in the material post processing. Here, an in situ grafting approach is designed to fabricate thermally conductive, electrically insulating and post-melt processable polystyrene (PS)/BN nanosphere (BNNS) nanocomposites by initiating styrene (St) on the surface functionalized BNNSs via reversible addition fragmentation chain transfer polymerization. The nanocomposites exhibit significantly enhanced thermal conductivity. For example, at a St/BN feeding ratio of 5:1, an enhancement ratio of 1375% is achieved in comparison with pure PS. Moreover, the dielectric properties of the nanocomposites show a desirable weak dependence on frequency, and the dielectric loss tangent of the nanocomposites remains at a very low level. More importantly, the nanocomposites can be subjected to multiple melt processing to form different shapes. Our method can become a universal approach to prepare thermally conductive, electrically insulating and melt-processable polymer nanocomposites with diverse monomers and nanofillers. (paper)

  15. Insulating materials for cables: state of the technology and future developments

    Energy Technology Data Exchange (ETDEWEB)

    Blechschmidt, H H [Hessische Elektrizitaets-A.G., Darmstadt (Germany, F.R.)

    1977-02-01

    This article gives a summary of old and new insulating materials for electrical cables. The electrical properties of some polymer insulating materials (PVC, polyethelene (PE), polymerised polyethelene (VPE), polypropylene) are compared in a table with the properties of paper insulation. The changeover from oiled paper to plastic insulation is almost complete for low voltage cables. Soft PVC is the dominant insulating material in this field. For medium voltage cables (10 kV and 20 kV supplies) and for high voltage cables (60 kV and 110 kV supplies) there is a trend to plastic PE/VPE, because these insulating materials have better electrical properties than PVC.

  16. Conformally encapsulated multi-electrode arrays with seamless insulation

    Energy Technology Data Exchange (ETDEWEB)

    Tabada, Phillipe J.; Shah, Kedar G.; Tolosa, Vanessa; Pannu, Satinderall S.; Tooker, Angela; Delima, Terri; Sheth, Heeral; Felix, Sarah

    2016-11-22

    Thin-film multi-electrode arrays (MEA) having one or more electrically conductive beams conformally encapsulated in a seamless block of electrically insulating material, and methods of fabricating such MEAs using reproducible, microfabrication processes. One or more electrically conductive traces are formed on scaffold material that is subsequently removed to suspend the traces over a substrate by support portions of the trace beam in contact with the substrate. By encapsulating the suspended traces, either individually or together, with a single continuous layer of an electrically insulating material, a seamless block of electrically insulating material is formed that conforms to the shape of the trace beam structure, including any trace backings which provide suspension support. Electrical contacts, electrodes, or leads of the traces are exposed from the encapsulated trace beam structure by removing the substrate.

  17. Vivitron 1995, transient voltage simulation, high voltage insulator tests, electric field calculation

    International Nuclear Information System (INIS)

    Frick, G.; Osswald, F.; Heusch, B.

    1996-01-01

    Preliminary investigations showed clearly that, because of the discrete electrode structure of the Vivitron, important overvoltage leading to insulator damage can appear in case of a spark. The first high voltage tests showed damage connected with such events. This fact leads to a severe voltage limitation. This work describes, at first, studies made to understand the effects of transients and the associated over-voltage appearing in the Vivitron. Then we present the high voltage tests made with full size Vivitron components using the CN 6 MV machine as a pilot machine. Extensive field calculations were made. These involve simulations of static stresses and transient overvoltages, on insulating boards and electrodes. This work gave us the solutions for arrangements and modifications in the machine. After application, the Vivitron runs now without any sparks and damage at 20 MV. In the same manner, we tested column insulators of a new design and so we will find out how to get to higher voltages. Electric field calculation around the tie bars connecting the discrete electrodes together showed field enhancements when the voltages applied on the discrete electrodes are not equally distributed. This fact is one of the sources of discharges and voltage limitations. A scenario of a spark event is described and indications are given how to proceed towards higher voltages, in the 30 MV range. (orig.)

  18. Voltage- and current-activated metal–insulator transition in VO2-based electrical switches: a lifetime operation analysis

    Directory of Open Access Journals (Sweden)

    Aurelian Crunteanu, Julien Givernaud, Jonathan Leroy, David Mardivirin, Corinne Champeaux, Jean-Christophe Orlianges, Alain Catherinot and Pierre Blondy

    2010-01-01

    Full Text Available Vanadium dioxide is an intensively studied material that undergoes a temperature-induced metal–insulator phase transition accompanied by a large change in electrical resistivity. Electrical switches based on this material show promising properties in terms of speed and broadband operation. The exploration of the failure behavior and reliability of such devices is very important in view of their integration in practical electronic circuits. We performed systematic lifetime investigations of two-terminal switches based on the electrical activation of the metal–insulator transition in VO2 thin films. The devices were integrated in coplanar microwave waveguides (CPWs in series configuration. We detected the evolution of a 10 GHz microwave signal transmitted through the CPW, modulated by the activation of the VO2 switches in both voltage- and current-controlled modes. We demonstrated enhanced lifetime operation of current-controlled VO2-based switching (more than 260 million cycles without failure compared with the voltage-activated mode (breakdown at around 16 million activation cycles. The evolution of the electrical self-oscillations of a VO2-based switch induced in the current-operated mode is a subtle indicator of the material properties modification and can be used to monitor its behavior under various external stresses in sensor applications.

  19. Effect of pollutant gases on electrical insulators deterioration

    Directory of Open Access Journals (Sweden)

    Zamarad, A.

    2000-06-01

    Full Text Available In this work ceramic materials as electrical insulators have been exposed in laboratory-based chambers. Water contact angle and FTIR of the surface before and after pollutant exposures have been studied. The results indicated that the reaction between the policrete and the atmospheric pollutant produce some salts deposits, some hydrolysis over the resin surface, modifying water contact angle.

    En este trabajo se exponen en cámaras atmosféricas de laboratorio materiales cerámicos usados como aislantes eléctricos. Se realiza un estudio de la superficie expuesta a la degradación medioambiental a través del ángulo de contacto de una gota de agua y de las sales depositadas, determinándose éstas últimas por espectroscopia infrarroja. Los resultados revelan el depósito de varias sales sobre la superficie de la muestra, e hidrólisis sobre la superficie de la resina, modificando el ángulo de contacto.

  20. Insulation design of cryogenic bushing for superconducting electric power applications

    Energy Technology Data Exchange (ETDEWEB)

    Koo, J.Y., E-mail: koojy@hanyang.ac.kr [Department of Electronics, Electrical, Control and Instrumentation Engineering, Hanyang University, Ansan 426-791 (Korea, Republic of); Lee, Y.J.; Shin, W.J.; Kim, Y.H. [Department of Electronics, Electrical, Control and Instrumentation Engineering, Hanyang University, Ansan 426-791 (Korea, Republic of); Kim, J.T. [Department of Electrical Engineering, Daejin University, Pocheon 487-711 (Korea, Republic of); Lee, B.W. [Department of Electronics, Electrical, Control and Instrumentation Engineering, Hanyang University, Ansan 426-791 (Korea, Republic of); Lee, S.H., E-mail: k720lsh@kins.re.kr [Expert Group Electric and Control Department, Korea Institute of Nuclear Safety, Daejeon 305-600 (Korea, Republic of)

    2013-01-15

    Highlights: ► In this paper, design factors of cryogenic bushings were discussed and test results of specimen were introduced in detail. ► We focused on the comparative study of breakdown characteristics of different electrode materials. ► Puncture and creepage breakdown characteristics were analyzed based on the withstand voltage. ► We obtained the basic design factors of extra high voltage condenser bushing. ► We obtained the basic design factors of extra high voltage condenser bushing, which could be used in cryogenic environment. -- Abstract: Recently, the superconductivity projects to develop commercial superconducting devices for extra high voltage transmission lines have been undergoing in many countries. One of the critical components to be developed for high voltage superconducting devices, including superconducting transformers, cables, and fault current limiters, is a high voltage bushing, to supply high current to devices without insulating difficulties, that is designed for cryogenic environments. Unfortunately, suitable bushings for HTS equipment were not fully developed for some cryogenic insulation issues. Such high voltage bushings would need to provide electrical insulation capabilities from room temperature to cryogenic temperatures. In this paper, design factors of cryogenic bushings were discussed and test results of specimen were introduced in detail. First, the dielectric strength of three kinds of metals has been measured with uniform and non-uniform electrodes by withstand voltage of impulse and AC breakdown test in LN{sub 2}. Second, puncture breakdown voltage of glass fiber reinforced plastics (GFRPs) plates has been analyzed with non-uniform electrodes. Finally, creepage discharge voltages were measured according to the configuration of non-uniform and uniform electrode on the FRP plate. From the test results, we obtained the basic design factors of extra high voltage condenser bushing, which could be used in cryogenic

  1. Two-dimensional hexagonal boron nitride as lateral heat spreader in electrically insulating packaging

    International Nuclear Information System (INIS)

    Bao, Jie; Huang, Shirong; Zhang, Yong; Lu, Xiuzhen; Yuan, Zhichao; Jeppson, Kjell; Liu, Johan; Edwards, Michael; Fu, Yifeng

    2016-01-01

    The need for electrically insulating materials with a high in-plane thermal conductivity for lateral heat spreading applications in electronic devices has intensified studies of layered hexagonal boron nitride (h-BN) films. Due to its physicochemical properties, h-BN can be utilised in power dissipating devices such as an electrically insulating heat spreader material for laterally redistributing the heat from hotspots caused by locally excessive heat flux densities. In this study, two types of boron nitride based heat spreader test structures have been assembled and evaluated for heat dissipation. The test structures separately utilised a few-layer h-BN film with and without graphene enhancement drop coated onto the hotspot test structure. The influence of the h-BN heat spreader films on the temperature distribution across the surface of the hotspot test structure was studied at a range of heat flux densities through the hotspot. It was found that the graphene-enhanced h-BN film reduced the hotspot temperature by about 8–10 °C at a 1000 W cm −2 heat flux density, a temperature decrease significantly larger than for h-BN film without graphene enhancement. Finite element simulations of the h-BN film predict that further improvements in heat spreading ability are possible if the thermal contact resistance between the film and test chip are minimised. (paper)

  2. Heat transfer through the flat surface of Rutherford superconducting cable samples with novel pattern of electrical insulation immersed in He II

    Science.gov (United States)

    Strychalski, M.; Chorowski, M.; Polinski, J.

    2014-05-01

    Future accelerator magnets will be exposed to heat loads that exceed even by an order of magnitude presently observed heat fluxes transferred to superconducting magnet coils. To avoid the resistive transition of the superconducting cables, the efficiency of heat transfer between the magnet structure and the helium must be significantly increased. This can be achieved through the use of novel concepts of the cable’s electrical insulation wrapping, characterized by an enhanced permeability to helium while retaining sufficient electrical resistivity. This paper presents measurement results of the heat transfer through Rutherford NbTi cable samples immersed in a He II bath and subjected to the pressure loads simulating the counteracting of the Lorentz forces observed in powered magnets. The Rutherford cable samples that were tested used different electrical insulation wrapping schemes, including the scheme that is presently used and the proposed scheme for future LHC magnets. A new porous polyimide cable insulation with enhanced helium permeability was proposed in order to improve the evacuation of heat form the NbTi coil to He II bath. These tests were performed in a dedicated Claudet-type cryostat in pressurized He II at 1.9 K and 1 bar.

  3. Use and benefit summary of General Electric Company thermocase insulated tubulars for steam enhanced oil recovery

    Energy Technology Data Exchange (ETDEWEB)

    Traynor, B.V. Jr.; Hawley, J.R.; Marziani, V.J.; Prevost, W.M.

    1982-01-01

    General Electric Co.'s (GE) first well-bore insulation in 1969 resulted from the industry's need to produce hot oil on Alaska's North Slope without damaging the permafrost. In the past 3 yr, over 500,000 linear ft of GE's Thermocase has been sold. Thermocase tubulars are in use in California, Wyoming, Texas, Canada, Venezuela, and the USSR. Thermocase insulated tubulars are being used in a wide range of reservoirs under a variety of completion designs. This study discusses field experience, thermal completion benefits afforded by Thermocase tubulars, a quantified economic evaluation in a 1000-ft application, as well as GE's product verification, test and rigid quality control program.

  4. CONTRIBUTIONS TO EVALUATION OF THE BIODEGRADABILITY BY ASPERGILLUS NIGER AND OTHER FUNGI’S OF SOME INSULATING OILS

    Directory of Open Access Journals (Sweden)

    RADU E.

    2015-06-01

    Full Text Available Mineral insulating oils used in electrical equipment because of their toxic organic substances and xenobiotic, represents a major risk to the environment - to accidental spills pollute soil, groundwater and surface water. By microbiological tests were evaluated the biodegradability of some insulating oils used in electrical equipment. The assays were performed in comparison with edible sunflower oil and with a control sample (culture medium - without oil. The experimental results indicate that the mineral oils are more readily biodegradable than synthetic ester oil and vegetable oils. It was also found that oils with high sulfur content are more readily biodegradable.

  5. Analysis and comparison of magnetic sheet insulation tests

    Science.gov (United States)

    Marion-Péra, M. C.; Kedous-Lebouc, A.; Cornut, B.; Brissonneau, P.

    1994-05-01

    Magnetic circuits of electrical machines are divided into coated sheets in order to limit eddy currents. The surface insulation resistance of magnetic sheets is difficult to evaluate because it depends on parameters like pressure and covers a wide range of values. Two methods of measuring insulation resistance are analyzed: the standardized 'Franklin device' and a tester developed by British Steel Electrical. Their main drawback is poor local repeatability. The Franklin method allows better quality control of industrial process because it measures only one insulating layer at a time. It also gives more accurate images of the distribution of possible defects. Nevertheless, both methods lead to similar classifications of insulation efficiency.

  6. PD-pulse characteristics in rotating machine insulation

    DEFF Research Database (Denmark)

    Holbøll, Joachim; Henriksen, Mogens; Jensen, A

    1994-01-01

    In this paper results are presented from investigations on partial discharges (PD) in insulation systems, resembling the stator insulation in high voltage rotating machines. A model, simulating a stator winding in a slot, has been developed, consisting of simple rotating machine insulation test...... bars with epoxy/mica insulation, mounted between steel sheets forming a dot, in order to investigate the fundamental behaviour of PD in insulation defects in epoxy/mica insulation and the characteristics of the resulting electrical pulses. Stator slot couplers (SSC) were used to detect pulses coming...

  7. Technique eliminates high voltage arcing at electrode-insulator contact area

    Science.gov (United States)

    Mealy, G.

    1967-01-01

    Coating the electrode-insulator contact area with silver epoxy conductive paint and forcing the electrode and insulator tightly together into a permanent connection, eliminates electrical arcing in high-voltage electrodes supplying electrical power to vacuum facilities.

  8. Electrically controlled crossing of energy levels in quantum dots in two-dimensional topological insulators

    Energy Technology Data Exchange (ETDEWEB)

    Sukhanov, Aleksei A.

    2017-05-15

    We study the energy spectra of bound states in quantum dots (QDs) formed by an electrostatic potential in two-dimensional topological insulator (TI) and their transformation with changes in QD depth and radius. It is found that, unlike a trivial insulator, the energy difference between the levels of the ground state and first excited state can decrease with decreasing the radius and increasing the depth of the QD so that these levels intersect under some critical condition. The crossing of the levels results in unusual features of optical properties caused by intraceneter electron transitions. In particular, it leads to significant changes of light absorption due to electron transitions between such levels and to the transient electroluminescence induced by electrical tuning of QD and TI parameters. In the case of magnetic TIs, the polarization direction of the absorbed or emitted circularly polarized light is changed due to the level crossing.

  9. Electrically controlled crossing of energy levels in quantum dots in two-dimensional topological insulators

    Science.gov (United States)

    Sukhanov, Aleksei A.

    2017-05-01

    We study the energy spectra of bound states in quantum dots (QDs) formed by an electrostatic potential in two-dimensional topological insulator (TI) and their transformation with changes in QD depth and radius. It is found that, unlike a trivial insulator, the energy difference between the levels of the ground state and first excited state can decrease with decreasing the radius and increasing the depth of the QD so that these levels intersect under some critical condition. The crossing of the levels results in unusual features of optical properties caused by intraceneter electron transitions. In particular, it leads to significant changes of light absorption due to electron transitions between such levels and to the transient electroluminescence induced by electrical tuning of QD and TI parameters. In the case of magnetic TIs, the polarization direction of the absorbed or emitted circularly polarized light is changed due to the level crossing.

  10. All-electric spin modulator based on a two-dimensional topological insulator

    Energy Technology Data Exchange (ETDEWEB)

    Xiao, Xianbo; Ai, Guoping [School of Computer Science, Jiangxi University of Traditional Chinese Medicine, Nanchang 330004 (China); Liu, Ying; Yang, Shengyuan A., E-mail: shengyuan-yang@sutd.edu.sg [Research Laboratory for Quantum Materials, Singapore University of Technology and Design, Singapore 487372 (Singapore); Liu, Zhengfang [School of Science, East China Jiaotong University, Nanchang 330013 (China); Zhou, Guanghui, E-mail: ghzhou@hunnu.edu.cn [Key Laboratory for Low-Dimensional Structures and Quantum Manipulation (Ministry of Education), and Synergetic Innovation Center for Quantum Effects and Applications, Hunan Normal University, Changsha 410081 (China)

    2016-01-18

    We propose and investigate a spin modulator device consisting of two ferromagnetic leads connected by a two-dimensional topological insulator as the channel material. It exploits the unique features of the topological spin-helical edge states, such that the injected carriers with a non-collinear spin-polarization direction would travel through both edges and show interference effect. The conductance of the device can be controlled in a simple and all-electric manner by a side-gate voltage, which effectively rotates the spin-polarization of the carrier. At low voltages, the rotation angle is linear in the gate voltage, and the device can function as a good spin-polarization rotator by replacing the drain electrode with a non-magnetic material.

  11. A Classroom Activity for Teaching Electric Polarization of Insulators and Conductors

    Science.gov (United States)

    Deligkaris, Christos

    2018-04-01

    The phenomenon of electric polarization is crucial to student understanding of forces exerted between charged objects and insulators or conductors, the process of charging by induction, and the behavior of electroscopes near charged objects. In addition, polarization allows for microscopic-level models of everyday-life macroscopic-level phenomena. Textbooks may adequately discuss polarization, but there is little material in active learning labs and tutorials on this topic. Since polarization of materials is a microscopic phenomenon, instructors often use diagrams and figures on the classroom board to explain the process in a lecture setting. In this paper I will describe a classroom activity where the students play the role of electrons as an alternative option.

  12. Investigation of Vacuum Insulator Surface Dielectric Strength with Nanosecond Pulses

    International Nuclear Information System (INIS)

    Nunnally, W.C.; Krogh, M.; Williams, C.; Trimble, D.; Sampayan, S.; Caporaso, G.

    2003-01-01

    The maximum vacuum insulator surface dielectric strength determines the acceleration electric field gradient possible in a short pulse accelerator. Previous work has indicated that higher electric field strengths along the insulator-vacuum interface might be obtained as the pulse duration is decreased. In this work, a 250 kV, single ns wide impulse source was applied to small diameter, segmented insulators samples in a vacuum to evaluate the multi-layer surface dielectric strength of the sample construction. Resonances in the low inductance test geometry were used to obtain unipolar, pulsed electric fields in excess of 100 MV/m on the insulator surface. The sample construction, experimental arrangement and experimental results are presented for the initial data in this work. Modeling of the multi-layer structure is discussed and methods of improving insulator surface dielectric strength in a vacuum are proposed

  13. Detection of UV Pulse from Insulators and Application in Estimating the Conditions of Insulators

    Science.gov (United States)

    Wang, Jingang; Chong, Junlong; Yang, Jie

    2014-10-01

    Solar radiation in the band of 240-280 nm is absorbed by the ozone layer in the atmosphere, and corona discharges from high-voltage apparatus emit in air mainly in the 230-405 nm range of ultraviolet (UV), so the band of 240-280 nm is called UV Solar Blind Band. When the insulators in a string deteriorate or are contaminated, the voltage distribution along the string will change, which causes the electric fields in the vicinity of insulators change and corona discharge intensifies. An UV pulse detection method to check the conditions of insulators is presented based on detecting the UV pulse among the corona discharge, then it can be confirmed that whether there exist faulty insulators and whether the surface contamination of insulators is severe for the safe operation of power systems. An UV-I Insulator Detector has been developed, and both laboratory tests and field tests have been carried out which demonstrates the practical viability of UV-I Insulator Detector for online monitoring.

  14. Using Expert Systems in Evaluation of the State of High Voltage Machine Insulation Systems

    Directory of Open Access Journals (Sweden)

    K. Záliš

    2000-01-01

    Full Text Available Expert systems are used for evaluating the actual state and future behavior of insulating systems of high voltage electrical machines and equipment. Several rule-based expert systems have been developed in cooperation with top diagnostic workplaces in the Czech Republic for this purpose. The IZOLEX expert system evaluates diagnostic measurement data from commonly used offline diagnostic methods for the diagnostic of high voltage insulation of rotating machines, non-rotating machines and insulating oils. The CVEX expert system evaluates the discharge activity on high voltage electrical machines and equipment by means of an off-line measurement. The CVEXON expert system is for evaluating the discharge activity by on-line measurement, and the ALTONEX expert system is the expert system for on-line monitoring of rotating machines. These developed expert systems are also used for educating students (in bachelor, master and post-graduate studies and in courses which are organized for practicing engineers and technicians and for specialists in the electrical power engineering branch. A complex project has recently been set up to evaluate the measurement of partial discharges. Two parallel expert systems for evaluating partial dischatge activity on high voltage electrical machines will work at the same time in this complex evaluating system.

  15. Development of insulating coatings for liquid metal blankets

    International Nuclear Information System (INIS)

    Malang, S.; Borgstedt, H.U.; Farnum, E.H.; Natesan, K.; Vitkovski, I.V.

    1994-07-01

    It is shown that self-cooled liquid metal blankets are feasible only with electrically insulating coatings at the duct walls. The requirements on the insulation properties are estimated by simple analytical models. Candidate insulator materials are selected based on insulating properties and thermodynamic consideration. Different fabrication technologies for insulating coatings are described. The status of the knowledge on the most crucial feasibility issue, the degradation of the resisivity under irradiation, is reviewed

  16. Insulating characteristics of polyvinyl alcohol for integrated electronics

    International Nuclear Information System (INIS)

    Van Etten, Eliana A.; Ximenes, Eder S.; Tarasconi, Lucas T.; Garcia, Irene T.S.; Forte, Maria M.C.; Boudinov, Henri

    2014-01-01

    The aim of this work is to evaluate the effects of molecular weight, hydrolysis degree, and cross-link on the performance of Polyvinyl Alcohol (PVA) when applied as dielectric material in organic field effect transistors. For this purpose, metal–insulator-structures and polymeric films were characterized. The polymer structure was analyzed by thermogravimetry and calorimetry, and the electrical characterization of the films was performed through current–voltage and capacitance–voltage curves; and dielectric spectrometry. Cross-linkage, followed by hydrolysis degree, presented the major impact on polymer properties, due to the strong influence on chain mobility. The chain mobility increases the dielectric response and decreases the insulation capacity, generating the need to compromise between these two properties. The largest drawback encountered was the high sensitivity of the films to ambient humidity. The best performance of the organic insulator was obtained from cross-linked films made of an incompletely hydrolyzed PVA. - Highlights: • Effect of molecular weight, hydrolysis and cross-link on polyvinyl alcohol (PVA) dielectric • Cross-linkage, followed by hydrolysis, showed the major impact on properties. • Cross-linkage followed by hydrolysis showed the strongest effect on chain mobility. • Best dielectric performance: cross-linked films made of incompletely hydrolyzed PVA • Largest drawback is the high sensitivity of the films to ambient humidity

  17. Cooper Pairs in Insulators?

    International Nuclear Information System (INIS)

    Valles, James

    2008-01-01

    Nearly 50 years elapsed between the discovery of superconductivity and the emergence of the microscopic theory describing this zero resistance state. The explanation required a novel phase of matter in which conduction electrons joined in weakly bound pairs and condensed with other pairs into a single quantum state. Surprisingly, this Cooper pair formation has also been invoked to account for recently uncovered high-resistance or insulating phases of matter. To address this possibility, we have used nanotechnology to create an insulating system that we can probe directly for Cooper pairs. I will present the evidence that Cooper pairs exist and dominate the electrical transport in these insulators and I will discuss how these findings provide new insight into superconductor to insulator quantum phase transitions.

  18. Correlation analysis between ceramic insulator pollution and acoustic emissions

    Directory of Open Access Journals (Sweden)

    Benjamín Álvarez-Nasrallah

    2015-01-01

    Full Text Available Most of the studies related to insulator pollution are normally performed based on individual analysis among leakage current, relative humidity and equivalent salt deposit density (ESDD. This paper presents a correlation analysis between the leakage current and the acoustic emissions measured in a 230 kV electrical substations in the city of Barranquilla, Colombia. Furthermore, atmospheric variables were considered to develop a characterization model of the insulator contamination process. This model was used to demonstrate that noise emission levels are a reliable indicator to detect and characterize pollution on high voltage insulators. The correlation found amount the atmospheric, electrical and sound variables allowed to determine the relations for the maintenance of ceramic insulators in high-polluted areas. In this article, the results on the behavior of the leakage current in ceramic insulators and the sound produced with different atmospheric conditions are shown, which allow evaluating the best time to clean the insulator at the substation. Furthermore, by experimentation on site and using statistical models, the correlation between ambient variables and the leakage current of insulators in an electrical substation was obtained. Some of the problems that bring the external noise were overcome using multiple microphones and specialized software that enabled properly filter the sound and better measure the variables.

  19. Development of electrically insulating self-healing coatings in vanadium alloys for lithium fusion reactor

    International Nuclear Information System (INIS)

    1999-01-01

    Problems on electrically insulating self-healing coatings (SHC) on vanadium alloys for lithium fusion reactor systems are considered. In particular, the SHC stability and radiation resistance in lithium and effect of magnetic field on the efficiency of the TNR lithium systems are studied. New technological methods for application of self-healing coatings and study on their properties are developed. The vanadium-lithium materials testing in pile loops for solution of the above problems under conditions of the lithium TNR is described [ru

  20. Radiation effects on insulators for superconducting magnets

    International Nuclear Information System (INIS)

    Kernohan, R.H.; Coltman, R.R. Jr.; Long, C.J.

    1978-01-01

    In order to determine the radiation stability of electrical insulation that could be used in a superconducting magnet for containment of the plasma in a fusion energy device, 55 specimens of eight types of organic insulation were irradiated to a dose of about 2 x 10 8 R (2 x 10 6 J/Kg) at a temperature of 4.8 K in the Low-Temperature Irradiation Facility in the Bulk Shielding Reactor at Oak Ridge National Laboratory. Four of the specimens were monitored for changes in electrical resistivity during the irradiation. The initial resistivities, which were of the order of 10 14 Ω cm, decreased to about 10 13 Ω cm under the influence of a weak radiation field. At full-power reactor operation (2 MW), the resistivities dropped to about 10 11 Ω cm, but changed little during the irradiation. After the irradiation the resistivities increased, but not to the initial values, because of residual radioactivity near or in the experiment assembly. Restoration to near the initial resistivity values was later observed upon warming the specimens to room temperature and purging the irradiation chamber. The latter result may be related to outgassing induced by the irradiation

  1. Measurement methods and interpretation algorithms for the determination of the remaining lifetime of the electrical insulation

    Directory of Open Access Journals (Sweden)

    Engster F.

    2005-12-01

    Full Text Available The paper presents a set of on-line and off-line measuring methods for the dielectric parameters of the electric insulation as well as the method of results interpretation aimed to determine the occurence of a damage and to set up the its speed of evolution. These results lead finally to the determination of the life time under certain imposed safety conditions. The interpretation of the measurement results is done based on analytical algorithms allowing also the calculation of the index of correlation between the real results and the mathematical interpolation. It is performed a comparative analysis between different measuring and interpretation methods. There are considered certain events occurred during the measurement performance including their causes. The working-out of the analytical methods has been improved during the during the dielectric measurements performance for about 25 years at a number of 140 turbo and hydro power plants. Finally it is proposed a measurement program to be applied and which will allow the correlation of the on-line and off-line dielectric measurement obtaining thus a reliable technology of high accuracy level for the estimation of the available lifetime of electrical insulation.

  2. Aluminum nitride insulating films for MOSFET devices

    Science.gov (United States)

    Lewicki, G. W.; Maserjian, J.

    1972-01-01

    Application of aluminum nitrides as electrical insulator for electric capacitors is discussed. Electrical properties of aluminum nitrides are analyzed and specific use with field effect transistors is defined. Operational limits of field effect transistors are developed.

  3. Research of long pulse high current diode radial insulation

    International Nuclear Information System (INIS)

    Tan Jie; Chang Anbi; Hu Kesong; Liu Qingxiang; Ma Qiaosheng; Liu Zhong

    2002-01-01

    A radial insulation structure which is used in long pulse high current diode is introduced. The theory of vacuum flashover and the idea of design are briefly introduced. In the research, cone-shaped insulator was used. The geometry structure parameters were optimized by simulating the static electrical field distribution. Experiment was done on a pulse power source with 200 ns pulse width. The maximum voltage 750 kV was obtained, and the average stand-off electrical field of insulator is about 50 kV/cm

  4. Flame spread over electrical wire with AC electric fields: Internal circulation, fuel vapor-jet, spread rate acceleration, and molten insulator dripping

    KAUST Repository

    Lim, Seungjae

    2015-04-01

    The effect of electric field on the characteristics of flame spread along a polyethylene (PE) insulated electrical wire was investigated experimentally by varying the AC frequency and voltage applied to the wire. The results showed that the flame spread rate was accelerated due to the convergence of electric flux near the end of wire, having three distinct regimes depending on applied voltage. In each regime, several subregimes could be identified depending on AC frequency. Flame shape (height and width) and slanted direction of the spreading flame were influenced differently. Fuel-vapor jets were ejected from the molten PE surface even for the baseline case without the application of an electric field; this could be attributed to the bursting of fuel vapor bubbles generated from internal boiling at the molten PE surface. An internal circulation of molten-PE was also observed as a result of non-uniform heating by the spreading flame. In the high voltage regime with a high AC frequency, excessive dripping of molten PE led to flame extinction.

  5. DC breakdown characteristics of silicone polymer composites for HVDC insulator applications

    Science.gov (United States)

    Han, Byung-Jo; Seo, In-Jin; Seong, Jae-Kyu; Hwang, Young-Ho; Yang, Hai-Won

    2015-11-01

    Critical components for HVDC transmission systems are polymer insulators, which have stricter requirements that are more difficult to achieve compared to those of HVAC insulators. In this study, we investigated the optimal design of HVDC polymer insulators by using a DC electric field analysis and experiments. The physical properties of the polymer specimens were analyzed to develop an optimal HVDC polymer material, and four polymer specimens were prepared for DC breakdown experiments. Single and reverse polarity breakdown tests were conducted to analyze the effect of temperature on the breakdown strength of the polymer. In addition, electric fields were analyzed via simulations, in which a small-scale polymer insulator model was applied to prevent dielectric breakdown due to electric field concentration, with four DC operating conditions taken into consideration. The experimental results show that the electrical breakdown strength and the electric field distribution exhibit significant differences in relation to different DC polarity transition procedures.

  6. THE ELECTROSTATIC CHARACTERISTICS OF LINEAR INSULATORS FOR CONTACT NETWORKS OF RAILWAYS

    Directory of Open Access Journals (Sweden)

    Ye. D. Kim

    2009-03-01

    Full Text Available On the base of numeric investigations on mathematical models of stationary electric field the basic electric performances of insulating suspensions from porcelain and polymeric insulators for contact nets of alternating and direct current are compared.

  7. Neutron and gamma irradiation effects on organic insulating materials for fusion magnets

    International Nuclear Information System (INIS)

    Maurer, W.

    1985-10-01

    Available low-temperature neutron and gamma irradiation data for organic insulating materials are collected and compared with room temperature data. Only the most promising polymers in terms of mechanical strength for magnet insulation are taken into account. For characterization and comparison of different materials the 75% dose is used, i.e. the dose, where the mechanical strength is reduced by 25%, and 75% is retained. For room temperature special prepared polyimide and epoxy materials reinforced with glass fibre retained 75% of the mechanical strength up to a dose of 7x10 7 Gy. For 5 K irradiation the best epoxy material retained the 75% dose up to 1x10 7 Gy, the best polyimide material up to 1x10 8 Gy. (orig.) [de

  8. Dielectric and Insulating Technology 2005 : Reviews & Forecasts

    Science.gov (United States)

    Okamoto, Tatsuki

    This article reports the state-of-art of TC-DEI ( Technical Committee of Dielectrics and Electrical Insulation of IEEJ) activites. The activiteis are basically based on the activites of 8-10 investigation committees under TC-DEI. Recent activites were categorized into three functions in this article and remarkable activity or trend for each category is mentioned as was done in the article of 2003. Thoese are activities on asset management (AI application and insulation diagnosis), activities on new insulating and functional materials (Nano composite) and activities on new insulation technology for power tansmission (high Tc superconducting cable insulation).

  9. Dielectric and Insulating Technology 2006 : Review & Forecast

    Science.gov (United States)

    Okamoto, Tatsuki

    This article reports the state-of-art of TC-DEI ( Technical Committee of Dielectrics and Electrical Insulation of IEEJ) activites. The activiteis are basically based on the activites of 8-10 investigation committees under TC-DEI. Recent activites were categorized into three functions in this article and remarkable activity or trend for each category is mentioned as was seen in the articles of 2005. Those are activities on asset management (AI application and insulation diagnosis), activities on new insulating and functional materials (Nano composite) and activities on new insulation technology for power tansmission (high Tc superconducting cable insulation).

  10. On effective holographic Mott insulators

    Energy Technology Data Exchange (ETDEWEB)

    Baggioli, Matteo; Pujolàs, Oriol [Institut de Física d’Altes Energies (IFAE), Universitat Autònoma de Barcelona,The Barcelona Institute of Science and Technology,Campus UAB, 08193 Bellaterra (Barcelona) (Spain)

    2016-12-20

    We present a class of holographic models that behave effectively as prototypes of Mott insulators — materials where electron-electron interactions dominate transport phenomena. The main ingredient in the gravity dual is that the gauge-field dynamics contains self-interactions by way of a particular type of non-linear electrodynamics. The electrical response in these models exhibits typical features of Mott-like states: i) the low-temperature DC conductivity is unboundedly low; ii) metal-insulator transitions appear by varying various parameters; iii) for large enough self-interaction strength, the conductivity can even decrease with increasing doping (density of carriers) — which appears as a sharp manifestation of ‘traffic-jam’-like behaviour; iv) the insulating state becomes very unstable towards superconductivity at large enough doping. We exhibit some of the properties of the resulting insulator-superconductor transition, which is sensitive to the momentum dissipation rate in a specific way. These models imply a clear and generic correlation between Mott behaviour and significant effects in the nonlinear electrical response. We compute the nonlinear current-voltage curve in our model and find that indeed at large voltage the conductivity is largely reduced.

  11. On effective holographic Mott insulators

    International Nuclear Information System (INIS)

    Baggioli, Matteo; Pujolàs, Oriol

    2016-01-01

    We present a class of holographic models that behave effectively as prototypes of Mott insulators — materials where electron-electron interactions dominate transport phenomena. The main ingredient in the gravity dual is that the gauge-field dynamics contains self-interactions by way of a particular type of non-linear electrodynamics. The electrical response in these models exhibits typical features of Mott-like states: i) the low-temperature DC conductivity is unboundedly low; ii) metal-insulator transitions appear by varying various parameters; iii) for large enough self-interaction strength, the conductivity can even decrease with increasing doping (density of carriers) — which appears as a sharp manifestation of ‘traffic-jam’-like behaviour; iv) the insulating state becomes very unstable towards superconductivity at large enough doping. We exhibit some of the properties of the resulting insulator-superconductor transition, which is sensitive to the momentum dissipation rate in a specific way. These models imply a clear and generic correlation between Mott behaviour and significant effects in the nonlinear electrical response. We compute the nonlinear current-voltage curve in our model and find that indeed at large voltage the conductivity is largely reduced.

  12. Electrical analysis of high dielectric constant insulator and metal gate metal oxide semiconductor capacitors on flexible bulk mono-crystalline silicon

    KAUST Repository

    Ghoneim, Mohamed T.; Rojas, Jhonathan Prieto; Young, Chadwin D.; Bersuker, Gennadi; Hussain, Muhammad Mustafa

    2015-01-01

    We report on the electrical study of high dielectric constant insulator and metal gate metal oxide semiconductor capacitors (MOSCAPs) on a flexible ultra-thin (25 μm) silicon fabric which is peeled off using a CMOS compatible process from a standard

  13. Focus on Organic Conductors

    Directory of Open Access Journals (Sweden)

    Shinya Uji, Takehiko Mori and Toshihiro Takahashi

    2009-01-01

    Full Text Available Organic materials are usually thought of as electrical insulators. Progress in chemical synthesis, however, has brought us a rich variety of conducting organic materials, which can be classified into conducting polymers and molecular crystals. Researchers can realize highly conducting molecular crystals in charge-transfer complexes, where suitable combinations of organic electron donor or acceptor molecules with counter ions or other organic molecules provide charge carriers. By means of a kind of chemical doping, the charge-transfer complexes exhibit high electrical conductivity and, thanks to their highly crystalline nature, even superconductivity has been observed. This focus issue of Science and Technology of Advanced Materials is devoted to the research into such 'organic conductors'The first organic metal was (TTF(TCNQ, which was found in 1973 to have high conductivity at room temperature and a metal–insulator transition at low temperatures. The first organic superconductor was (TMTSF2PF6, whose superconductivity under high pressures was reported by J´erome in 1980. After these findings, the research on organic conductors exploded. Hundreds of organic conductors have been reported, among which more than one hundred exhibit superconductivity. Recently, a single-component organic conductor has been found with metallic conductivity down to low temperatures.In these organic conductors, in spite of their simple electronic structures, much new physics has arisen from the low dimensionality. Examples are charge and spin density waves, characteristic metal–insulator transitions, charge order, unconventional superconductivity, superconductor–insulator transitions, and zero-gap conductors with Dirac cones. The discovery of this new physics is undoubtedly derived from the development of many intriguing novel organic conductors. High quality single crystals are indispensable to the precise measurement of electronic states.This focus issue

  14. Electrical Interfaces for Organic Nanodevices

    DEFF Research Database (Denmark)

    Henrichsen, Henrik Hartmann

    Optoelectronic applications of organic semiconductor materials is a research field, which recently came to the large scale consumer market in display technologies. Organic semiconductors are mainly applied in amorphous form offering fabrication control on a large scale. Crystalline organic...... semiconductors, where the molecular packing is more crucial, have not yet had a major impact in commercial products. This thesis describes development of new ways to electrically contact organic semiconductors. In particular, crystalline organic para-hexaphenylene (p6P) nanofibers have been used...... approaches. Creating the separator by partly oxidizing an Al cathode anodically is considered the most promising implementation, however further development would be necessary. During the project a group of collaborators managed to obtain electrically stimulated light emission in organic p6P nanofibers...

  15. Electrical transport across nanometric SrTiO3 and BaTiO3 barriers in conducting/insulator/conducting junctions

    Science.gov (United States)

    Navarro, H.; Sirena, M.; González Sutter, J.; Troiani, H. E.; del Corro, P. G.; Granell, P.; Golmar, F.; Haberkorn, N.

    2018-01-01

    We report the electrical transport properties of conducting/insulator/conducting heterostructures by studying current-voltage IV curves at room temperature. The measurements were obtained on tunnel junctions with different areas (900, 400 and 100 μm2) using a conducting atomic force microscope. Trilayers with GdBa2Cu3O7 (GBCO) as the bottom electrode, SrTiO3 or BaTiO3 (thicknesses between 1.6 and 4 nm) as the insulator barrier, and GBCO or Nb as the top electrode were grown by DC sputtering on (100) SrTiO3 substrates For SrTiO3 and BaTiO3 barriers, asymmetric IV curves at positive and negative polarization can be obtained using electrodes with different work function. In addition, hysteretic IV curves are obtained for BaTiO3 barriers, which can be ascribed to a combined effect of the FE reversal switching polarization and an oxygen vacancy migration. For GBCO/BaTiO3/GBCO heterostructures, the IV curves correspond to that expected for asymmetric interfaces, which indicates that the disorder affects differently the properties at the bottom and top interfaces. Our results show the role of the interface disorder on the electrical transport of conducting/insulator/conduction heterostructures, which is relevant for different applications, going from resistive switching memories (at room temperature) to Josephson junctions (at low temperatures).

  16. High-voltage polymeric insulated cables

    Energy Technology Data Exchange (ETDEWEB)

    Ross, A

    1987-01-01

    Reviews developments in high-voltage (here defined as 25 kV, 66 kV and 132 kV) polymeric insulated cables in the UK over the period 1979-1986, with particular reference to the experience of the Eastern Electricity Board. Outlines the background to the adoption of XPLE-insulated solid cable, and the design, testing, terminations, jointing and costs of 25 kV, 66 kV and 132 kV cables.

  17. 76 FR 16263 - Revision to Electric Reliability Organization Definition of Bulk Electric System

    Science.gov (United States)

    2011-03-23

    ...; Order No. 743-A] Revision to Electric Reliability Organization Definition of Bulk Electric System AGENCY... certain provisions of the Final Rule. Order No. 743 directed the Electric Reliability Organization (ERO) to revise the definition of the term ``bulk electric system'' through the ERO's Reliability Standards...

  18. 75 FR 72909 - Revision to Electric Reliability Organization Definition of Bulk Electric System

    Science.gov (United States)

    2010-11-26

    ... Bulk-Power System. See Rules Concerning Certification of the Electric Reliability Organization; and... Bulk-Power System in North America because it protects the reliability of the bulk electric system and... Electric Reliability Organization Definition of Bulk Electric System; Final Rule #0;#0;Federal Register...

  19. Application to the system of insulated of diagnosis in high-voltage motors by partial discharge

    International Nuclear Information System (INIS)

    Mikami, M.

    2005-01-01

    In order to detect electric insulators degradation of high-voltage electric motors at an early stage, measurements of partial discharge of operating high-voltage electric motors (about 150 units) in the nuclear power plants were conducted from 2001 to 2004 by the use of on-line monitoring systems that could measure partial discharge of electric insulators. Influencing factors for measured values were identified from measured data and evaluation criteria of electric insulators integrity were established based on variations of partial discharge values. (T. Tanaka)

  20. Irradiation effects on organic insulators

    International Nuclear Information System (INIS)

    Kasen, M.B.

    1986-01-01

    The overall objective of this work is to contribute to development of organic insulators having the cryogenic neutron irradiation resistance required for MFE systems utilizing superconducting magnet confinement. The system for producing standard 3.2-mm (0.125-in) diameter rod specimens discussed in previous reports has been further refined to permit the fabrication of both fiber-reinforced and heat-resin specimens from hot-melt resin systems. The method has been successfully used to produce very high quality specimens duplicating the G-11CR system and specimens from a variant of that system eliminating a boron-containing additive. We have also produced specimens from an epoxy system suitable for impregnation or potting operations and from a bismaleimide polyimide system. These materials will be used in the first irradiation program in the National Low Temperature Neutron Irradiation Facility (NLTNIF) reactor at Oak Ridge. We have refined the 4-K torsional shear test method for evaluating radiation degradation of the fiber-matrix interface and have developed a method of quantitatively measuring changes in fracture energy as a function of radiation dose. Cooperative work with laboratories in Japan and England in this area is continuing and plans are being formulated for joint production, irradiation, and testing of specimens

  1. CERTIFICATION OF THE RADIATION RESISTANCE OF COIL INSULATION MATERIAL

    CERN Document Server

    Polinski, J; Bogdan, P

    2013-01-01

    The goal of the WP 7.2.1 sub-task of the EuCARD program has been to determine the Nb$_{3}$Sn based accelerator magnet coil electrical insulation resistance against irradiation, which will occur in future accelerators. The scope of the certification covers determination of mechanical, electrical and thermal properties changes due to irradiation. The report presents a selection of the insulation material candidates for future accelerator magnets as well as the definition of the radiation certification methodology with respect of radiation type, energy, doses and irradiation conditions. The test methods and results of the electrical and mechanical insulation materials properties degradation due to irradiation are presented. Thermal conductivity and Kapitza resistance at temperature range from 1.5 K to 2.0 K (superfluid helium conditions) are given.

  2. Insulating oil, electrical for transformers and switches : a national standard of Canada

    International Nuclear Information System (INIS)

    Paniri, S.; Burford, G.; Martin, A.; Adragna, M.

    1997-01-01

    Standard specifications for insulating oil used in power transformers, instrument transformers, bushings, bulk oil circuit breakers, oil circuit reclosers, and switches were provided. The specifications are divided into Class A and Class B depending on the requirement for kinematic viscosity at -40 degrees C. A Class S oil is also introduced for oil circuit breakers. The standards were prepared by the Technical Committee on Transformer and Switch Oils under the jurisdiction of the Steering Committee on Electrical Engineering, and has been formally approved by these committees. It has been also approved as a National Standard of Canada by the Standards Council of Canada. The document provides a list of reference publications, describes the samples and test procedures, properties and delivery requirements. 1 tab

  3. Force and Motion Characteristics of Contamination Particles near the High Voltage End of UHVDC Insulator

    Directory of Open Access Journals (Sweden)

    Lei Lan

    2017-07-01

    Full Text Available It is important to reveal the relations of physical factors to deposition of contaminants on insulator. In this paper, the simulation model of high voltage end of insulator was established to study the force and motion characteristics of particles affected by electric force and airflow drag force near the ultra-high voltage direct current (UHVDC insulator. By finite element method, the electric field was set specially to be similar to the one near practical insulator, the steady fluid field was simulated. The electric force and air drag force were loaded on the uniformly charged particles. The characteristics of the two forces on particles, the relationship between quantity of electric charge on particles and probability of particles contacting the insulator were analyzed. It was found that, near the sheds, airflow drag force on particles is significantly greater than electric force with less electric charge. As the charge multiplies, electric force increases linearly, airflow drag force grows more slowly. There is a trend that the magnitude of electric force and drag force is going to similar. Meanwhile, the probability of particles contacting the insulator is increased too. However, at a certain level of charge which has different value with different airflow velocity, the contact probability has extremum here. After exceeding the value, as the charge increasing, the contact probability decreases gradually.

  4. Sheath insulator final test report, TFE Verification Program

    Energy Technology Data Exchange (ETDEWEB)

    1994-07-01

    The sheath insulator in a thermionic cell has two functions. First, the sheath insulator must electrically isolate the collector form the outer containment sheath tube that is in contact with the reactor liquid metal coolant. Second, The sheath insulator must provide for high uniform thermal conductance between the collector and the reactor coolant to remove away waste heat. The goals of the sheath insulator test program were to demonstrate that suitable ceramic materials and fabrication processes were available, and to validate the performance of the sheath insulator for TFE-VP requirements. This report discusses the objectives of the test program, fabrication development, ex-reactor test program, in-reactor test program, and the insulator seal specifications.

  5. Sheath insulator final test report, TFE Verification Program

    International Nuclear Information System (INIS)

    1994-07-01

    The sheath insulator in a thermionic cell has two functions. First, the sheath insulator must electrically isolate the collector form the outer containment sheath tube that is in contact with the reactor liquid metal coolant. Second, The sheath insulator must provide for high uniform thermal conductance between the collector and the reactor coolant to remove away waste heat. The goals of the sheath insulator test program were to demonstrate that suitable ceramic materials and fabrication processes were available, and to validate the performance of the sheath insulator for TFE-VP requirements. This report discusses the objectives of the test program, fabrication development, ex-reactor test program, in-reactor test program, and the insulator seal specifications

  6. Fate and transport of petroleum hydrocarbons in the environment case study: insulating oil

    International Nuclear Information System (INIS)

    Richards, S. L.

    1997-01-01

    A series of studies were conducted to develop the technical basis for establishing soil cleanup levels for electrical insulating oil that would protect human health and the environment in the State of Washington. Samples of insulating oil and ground water from electric utility sites were analyzed for physical and chemical properties. Oil dissolution and soil leachability tests were conducted to evaluate the mobility of the oil in the aqueous state. Results indicate that insulating oil is relatively immobile in the subsurface. As a result of this study, soil cleanup level for insulating oil at operating electrical substations in the State of Washington was increased from 200 mg/kg to 2000 mg/kg. 6 refs., 3 tabs

  7. 5th Duisburg thermal insulation days. Fuenfte Duisburger Waermedaemm-Tage

    Energy Technology Data Exchange (ETDEWEB)

    Agst, J. (ed.)

    1989-01-01

    This volume contains 18 specialist lectures mainly about the problems of thermal insulation in industrial furnaces and facility engineering. Among the subjects are: formed parts, monolithic lining materials and fillers of vermiculite; pyro-block-modular systems for furnaces (of the company DYKO-Morgan Fasertechnik); microporous insulating materials (KAOWOOL); properties of lightweight refractory bricks; thermal insulation in induction furnaces; vacuum moulded parts in electric furnace engineering; high temperature insulating materials with ceramic fibres; microtherm insulating materials. (MM).

  8. Topological Field Theory of Time-Reversal Invariant Insulators

    Energy Technology Data Exchange (ETDEWEB)

    Qi, Xiao-Liang; Hughes, Taylor; Zhang, Shou-Cheng; /Stanford U., Phys. Dept.

    2010-03-19

    We show that the fundamental time reversal invariant (TRI) insulator exists in 4 + 1 dimensions, where the effective field theory is described by the 4 + 1 dimensional Chern-Simons theory and the topological properties of the electronic structure is classified by the second Chern number. These topological properties are the natural generalizations of the time reversal breaking (TRB) quantum Hall insulator in 2 + 1 dimensions. The TRI quantum spin Hall insulator in 2 + 1 dimensions and the topological insulator in 3 + 1 dimension can be obtained as descendants from the fundamental TRI insulator in 4 + 1 dimensions through a dimensional reduction procedure. The effective topological field theory, and the Z{sub 2} topological classification for the TRI insulators in 2+1 and 3+1 dimensions are naturally obtained from this procedure. All physically measurable topological response functions of the TRI insulators are completely described by the effective topological field theory. Our effective topological field theory predicts a number of novel and measurable phenomena, the most striking of which is the topological magneto-electric effect, where an electric field generates a magnetic field in the same direction, with an universal constant of proportionality quantized in odd multiples of the fine structure constant {alpha} = e{sup 2}/hc. Finally, we present a general classification of all topological insulators in various dimensions, and describe them in terms of a unified topological Chern-Simons field theory in phase space.

  9. Voltage-driven magnetization control in topological insulator/magnetic insulator heterostructures

    Directory of Open Access Journals (Sweden)

    Michael E. Flatté

    2017-05-01

    Full Text Available A major barrier to the development of spin-based electronics is the transition from current-driven spin torque, or magnetic-field-driven magnetization reversal, to a more scalable voltage-driven magnetization reversal. To achieve this, multiferroic materials appear attractive, however the effects in current materials occur at very large voltages or at low temperatures. Here the potential of a new class of hybrid multiferroic materials is described, consisting of a topological insulator adjacent to a magnetic insulator, for which an applied electric field reorients the magnetization. As these materials lack conducting states at the chemical potential in their bulk, no dissipative charge currents flow in the bulk. Surface states at the interface, if present, produce effects similar to surface recombination currents in bipolar devices, but can be passivated using magnetic doping. Even without conducting states at the chemical potential, for a topological insulator there is a finite spin Hall conductivity provided by filled bands below the chemical potential. Spin accumulation at the interface with the magnetic insulator provides a torque on the magnetization. Properly timed voltage pulses can thus reorient the magnetic moment with only the flow of charge current required in the leads to establish the voltage. If the topological insulator is sufficiently thick the resulting low capacitance requires little charge current.

  10. Carbon nanotubes integrated in electrically insulated channels for lab-on-a-chip applications

    International Nuclear Information System (INIS)

    Mogensen, K B; Boggild, P; Kutter, J P; Gangloff, L; Teo, K B K; Milne, W I

    2009-01-01

    A fabrication process for monolithic integration of vertically aligned carbon nanotubes in electrically insulated microfluidic channels is presented. A 150 nm thick amorphous silicon layer could be used both for anodic bonding of a glass lid to hermetically seal the microfluidic glass channels and for de-charging of the wafer during plasma enhanced chemical vapor deposition of the carbon nanotubes. The possibility of operating the device with electroosmotic flow was shown by performing standard electrophoretic separations of 50 μM fluorescein and 50 μM 5-carboxyfluorescein in a 25 mm long column containing vertical aligned carbon nanotubes. This is the first demonstration of electroosmotic pumping and electrokinetic separations in microfluidic channels with a monolithically integrated carbon nanotube forest.

  11. Carbon nanotubes integrated in electrically insulated channels for lab-on-a-chip applications

    DEFF Research Database (Denmark)

    Mogensen, Klaus Bo; Gangloff, L.; Bøggild, Peter

    2009-01-01

    A fabrication process for monolithic integration of vertically aligned carbon nanotubes in electrically insulated microfluidic channels is presented. A 150 nm thick amorphous silicon layer could be used both for anodic bonding of a glass lid to hermetically seal the microfluidic glass channels...... and for de-charging of the wafer during plasma enhanced chemical vapor deposition of the carbon nanotubes. The possibility of operating the device with electroosmotic flow was shown by performing standard electrophoretic separations of 50 mu M fluorescein and 50 mu M 5-carboxyfluorescein in a 25 mm long...... column containing vertical aligned carbon nanotubes. This is the first demonstration of electroosmotic pumping and electrokinetic separations in microfluidic channels with a monolithically integrated carbon nanotube forest....

  12. Electrical insulation design and evaluation of 60 kV prototype condenser cone bushing for the superconducting equipment

    International Nuclear Information System (INIS)

    Shin, Woo-Ju; Lee, Jong-Geon; Hwang, Jae-Sang; Seong, Jae-Kyu; Lee, Bang-Wook

    2013-01-01

    Highlights: •The optimum design of condenser cone cryogenic bushing was investigated. •Multi-layer aluminum foils in the bushing insulation body was designed and analyzed. •The optimum electric field distribution was selected by simulation. •The 60 kV FRP condenser cone cryogenic bushing was fabricated and tested. •BIL test corresponding to IEC 60137 was successfully performed for the bushing. -- Abstract: A cryogenic bushing is an essential component to be developed for commercial applications of high voltage (HV) superconducting devices. Due to the steep temperature gradient of the ambient of cryogenic bushing, general gas bushing adopting SF6 gas as an insulating media could not be directly used due to the freezing of SF6 gas. Therefore, condenser type bushing with special material considering cryogenic environment would be better choice for superconducting equipment. Considering these circumstance, we focused on the design of condenser bushing made of fiber reinforced plastic (FRP). In case of the design of the condenser bushing, it is very important to reduce the electric field intensification on the mounted flange part of the cryostat, which is the most vulnerable part of bushings. In this paper, design factors of cryogenic bushing were analyzed, and finally 60 kV condenser bushing was fabricated and tested. In order to achieve optimal electric field configuration, the configuration of condenser cone was determined using 2D electric field simulation results. Based on the experimental and the analytical works, 60 kV FRP condenser bushing was fabricated. Finally, the fabricated condenser bushing has been tested by applying lightning impulse and AC overvoltage test. From the test results, it was possible to get satisfactory results which confirm the design of cryogenic bushing in cryogenic environment

  13. Electrical insulation design and evaluation of 60 kV prototype condenser cone bushing for the superconducting equipment

    Energy Technology Data Exchange (ETDEWEB)

    Shin, Woo-Ju, E-mail: shinwooju@hanyang.ac.kr; Lee, Jong-Geon; Hwang, Jae-Sang; Seong, Jae-Kyu; Lee, Bang-Wook, E-mail: bangwook@hanyang.ac.kr

    2013-11-15

    Highlights: •The optimum design of condenser cone cryogenic bushing was investigated. •Multi-layer aluminum foils in the bushing insulation body was designed and analyzed. •The optimum electric field distribution was selected by simulation. •The 60 kV FRP condenser cone cryogenic bushing was fabricated and tested. •BIL test corresponding to IEC 60137 was successfully performed for the bushing. -- Abstract: A cryogenic bushing is an essential component to be developed for commercial applications of high voltage (HV) superconducting devices. Due to the steep temperature gradient of the ambient of cryogenic bushing, general gas bushing adopting SF6 gas as an insulating media could not be directly used due to the freezing of SF6 gas. Therefore, condenser type bushing with special material considering cryogenic environment would be better choice for superconducting equipment. Considering these circumstance, we focused on the design of condenser bushing made of fiber reinforced plastic (FRP). In case of the design of the condenser bushing, it is very important to reduce the electric field intensification on the mounted flange part of the cryostat, which is the most vulnerable part of bushings. In this paper, design factors of cryogenic bushing were analyzed, and finally 60 kV condenser bushing was fabricated and tested. In order to achieve optimal electric field configuration, the configuration of condenser cone was determined using 2D electric field simulation results. Based on the experimental and the analytical works, 60 kV FRP condenser bushing was fabricated. Finally, the fabricated condenser bushing has been tested by applying lightning impulse and AC overvoltage test. From the test results, it was possible to get satisfactory results which confirm the design of cryogenic bushing in cryogenic environment.

  14. Design and construction of the mineral insulated magnets

    International Nuclear Information System (INIS)

    Kurokawa, S.; Hirabayashi, H.; Taino, M.; Tsuchiya, K.; Yamamoto, A.

    1978-01-01

    The radiation resistant magnets with mineral insulated coils are designed and constructed. The electrical insulation of the cable is maintained by magnesium oxide in the form of a powder held around the copper hollow conductor by a copper shieth. By the direct water cooling through a hollow conductor the sometimes conflicting requirements of good insulation and high field are fulfilled. The magnets can with stand more than 10 12 rad of absorbed dose. (author)

  15. Partial discharge characteristics of polymer nanocomposite materials in electrical insulation: a review of sample preparation techniques, analysis methods, potential applications, and future trends.

    Science.gov (United States)

    Izzati, Wan Akmal; Arief, Yanuar Z; Adzis, Zuraimy; Shafanizam, Mohd

    2014-01-01

    Polymer nanocomposites have recently been attracting attention among researchers in electrical insulating applications from energy storage to power delivery. However, partial discharge has always been a predecessor to major faults and problems in this field. In addition, there is a lot more to explore, as neither the partial discharge characteristic in nanocomposites nor their electrical properties are clearly understood. By adding a small amount of weight percentage (wt%) of nanofillers, the physical, mechanical, and electrical properties of polymers can be greatly enhanced. For instance, nanofillers in nanocomposites such as silica (SiO2), alumina (Al2O3) and titania (TiO2) play a big role in providing a good approach to increasing the dielectric breakdown strength and partial discharge resistance of nanocomposites. Such polymer nanocomposites will be reviewed thoroughly in this paper, with the different experimental and analytical techniques used in previous studies. This paper also provides an academic review about partial discharge in polymer nanocomposites used as electrical insulating material from previous research, covering aspects of preparation, characteristics of the nanocomposite based on experimental works, application in power systems, methods and techniques of experiment and analysis, and future trends.

  16. Design analysis of ceramic and polymer 150 kV insulators for tropical condition using quickfield software

    Science.gov (United States)

    Walukow, Stephy B.; Manjang, Salama; Zainuddin, Zahir; Samman, Faizal Arya

    2018-03-01

    This research is to analyze design of ceramic and polymer 150 kV insulators for the tropical area. The use of an insulator certainly requires an electric field. The leakage current and breakdown voltage this happens the contaminant on the surface of the insulator. This type of contaminant can be rain, dust, salt air, extreme weather (much in tropical climates), industrial pollutants and cracks on the surface resulting in collisions. The method used in this research is magnetic field and electric field isolator using Quicfield software. To get the test results variation ranges 20 kV, 70 kV and 150 kV. Side effects of magnetic and electric fields around the insulator. The simulation results show the accumulated contaminants on the surface. Planning should be done in insulator insulator on unstable insulator. Thus, the approach using this commercially available software can be applied to. Therefore, the development of further simulations on the different types of composite insulators used on.

  17. Morphology and crystalline-phase-dependent electrical insulating properties in tailored polypropylene for HVDC cables

    Science.gov (United States)

    Zha, Jun-Wei; Yan, Hong-Da; Li, Wei-Kang; Dang, Zhi-Min

    2016-11-01

    Polypropylene (PP) has become one promising material to potentially replace the cross-link polyethylene used for high voltage direct current cables. Besides the isotactic polypropylene, the block polypropylene (b-PP) and random polypropylene (r-PP) can be synthesized through the copolymerization of ethylene and propylene molecules. In this letter, the effect of morphology and crystalline phases on the insulating electrical properties of PP was investigated. It was found that the introduction of polyethylene monomer resulted in the formation of β and γ phases in b-PP and r-PP. The results from the characteristic trap energy levels indicated that the β and γ phases could induce deep electron traps which enable to capture the carriers. And the space charge accumulation was obviously suppressed. Besides, the decreased electrical conductivity was observed in b-PP and r-PP. It is attributed to the existence of deep traps which can effectively reduce the carrier mobility and density in materials.

  18. Measurement of polychlorinated biphenyls in solid waste such as transformer insulation paper by supercritical fluid extraction and gas chromatography electron capture detection.

    Science.gov (United States)

    Chikushi, Hiroaki; Fujii, Yuka; Toda, Kei

    2012-09-21

    In this work, a method for measuring polychlorinated biphenyls (PCBs) in contaminated solid waste was investigated. This waste includes paper that is used in electric transformers to insulate electric components. The PCBs in paper sample were extracted by supercritical fluid extraction and analyzed by gas chromatography-electron capture detection. The recoveries with this method (84-101%) were much higher than those with conventional water extraction (0.08-14%), and were comparable to those with conventional organic solvent extraction. Limit of detection was 0.0074 mg kg(-1) and measurable up to 2.5 mg kg(-1) for 0.5 g of paper sample. Data for real insulation paper by the proposed method agreed well with those by the conventional organic solvent extraction. Extraction from wood and concrete was also investigated and good performance was obtained as well as for paper samples. The supercritical fluid extraction is simpler, faster, and greener than conventional organic solvent extraction. Copyright © 2012 Elsevier B.V. All rights reserved.

  19. The change of electric field and of some other insulating properties during isochronal annealing in thermally poled Ge-doped silica films

    DEFF Research Database (Denmark)

    Liu, Q.M.; Poumellec, B.; Braga, D.

    2005-01-01

    induced electric field and other insulating properties like electron traps population and conductivity in high field. Concerning the change of the contrast at low dose arising from the poling electric field, we show that this field begins to disappear at around 450 degrees C and is erased completely...... at 650 degrees C. Using a larger dose allows measuring the change in conductivity contrast. We find a stability similar to the electric field with a disappearance around 450 similar to 650 degrees C. On the contrary, for intermediate dose, the contrast remains for larger annealing temperature. It allows...

  20. Study of heat transfer in superconducting cable electrical insulation of accelerator magnet cooled by superfluid helium; Etude des transferts de chaleur dans les isolations electriques de cables supraconducteurs d'aimant d'accelerateur refroidi par helium superfluide

    Energy Technology Data Exchange (ETDEWEB)

    Baudouy, B

    1996-10-04

    Heat transfer studies of electrical cable insulation in superconducting winding are of major importance for stability studies in superconducting magnets. This work presents an experimental heat transfer study in superconducting cables of Large Hadron Collider dipoles cooled by superfluid helium and submitted to volume heat dissipation due to beam losses. For NbTi magnets cooled by superfluid helium the most severe heat barrier comes from the electrical insulation of the cables. Heat behaviour of a winding is approached through an experimental model in which insulation characteristics can be modified. Different tests on insulation patterns show that heat transfer is influenced by superfluid helium contained in insulation even for small volume of helium (2 % of cable volume). Electrical insulation can be considered as a composite material made of a solid matrix with a helium channels network which cannot be modelled easily. This network is characterised by another experimental apparatus which allows to study transverse and steady-state heat transfer through an elementary insulation pattern. Measurements in Landau regime ({delta}T{approx}10{sup -5} to 10{sup -3} K) and in Gorter-Mellink regime ({delta}T>10{sup -3} K) and using assumptions that helium thermal paths and conduction in the insulation are decoupled allow to determine an equivalent channel area (10{sup -6} m{sup 2}) and an equivalent channel diameter (25 {mu}). (author)

  1. Standard Test Methods for Wet Insulation Integrity Testing of Photovoltaic Modules

    CERN Document Server

    American Society for Testing and Materials. Philadelphia

    2007-01-01

    1.1 These test methods provide procedures to determine the insulation resistance of a photovoltaic (PV) module, i.e. the electrical resistance between the module's internal electrical components and its exposed, electrically conductive, non-current carrying parts and surfaces. 1.2 The insulation integrity procedures are a combination of wet insulation resistance and wet dielectric voltage withstand test procedures. 1.3 These procedures are similar to and reference the insulation integrity test procedures described in Test Methods E 1462, with the difference being that the photovoltaic module under test is immersed in a wetting solution during the procedures. 1.4 These test methods do not establish pass or fail levels. The determination of acceptable or unacceptable results is beyond the scope of these test methods. 1.5 The values stated in SI units are to be regarded as the standard. 1.6 There is no similar or equivalent ISO standard. 1.7 This standard does not purport to address all of the safety conce...

  2. Preparation and dielectric investigation of organic metal insulator semiconductor (MIS) structures with a ferroelectric polymer

    Energy Technology Data Exchange (ETDEWEB)

    Kalbitz, Rene; Fruebing, Peter; Gerhard, Reimund [Department of Physics and Astronomy, University of Potsdam (Germany); Taylor, Martin [School of Electronic Engineering, Bangor University (United Kingdom)

    2010-07-01

    Ferroelectric field effect transistors (FeFETs) offer the prospect of an organic-based memory device. Since the charge transport in the semiconductor is confined to the interface region between the insulator and the semiconductor, the focus of the present study was on the investigation of this region in metal-insulator-semiconductor (MIS) capacitors using dielectric spectroscopy. Capacitance-Voltage (C-V) measurements at different frequencies as well as capacitance-frequency (C-f) measurements after applying different poling voltages were carried out. The C-V measurements yielded information about the frequency dependence of the depletion layer width as well as the number of charges stored at the semiconductor/ insulator interface. The results are compared to numerical calculations based on a model introduced by S. L. Miller (JAP, 72(12), 1992). The C-f measurements revealed three main relaxation processes. An equivalent circuit has been developed to model the frequency response of the MIS capacitor. With this model the origin of the three relaxations may be deduced.

  3. Defect design of insulation systems for photovoltaic modules

    Science.gov (United States)

    Mon, G. R.

    1981-01-01

    A defect-design approach to sizing electrical insulation systems for terrestrial photovoltaic modules is presented. It consists of gathering voltage-breakdown statistics on various thicknesses of candidate insulation films where, for a designated voltage, module failure probabilities for enumerated thickness and number-of-layer film combinations are calculated. Cost analysis then selects the most economical insulation system. A manufacturing yield problem is solved to exemplify the technique. Results for unaged Mylar suggest using fewer layers of thicker films. Defect design incorporates effects of flaws in optimal insulation system selection, and obviates choosing a tolerable failure rate, since the optimization process accomplishes that. Exposure to weathering and voltage stress reduces the voltage-withstanding capability of module insulation films. Defect design, applied to aged polyester films, promises to yield reliable, cost-optimal insulation systems.

  4. Design principles for HgTe based topological insulator devices

    Science.gov (United States)

    Sengupta, Parijat; Kubis, Tillmann; Tan, Yaohua; Povolotskyi, Michael; Klimeck, Gerhard

    2013-07-01

    The topological insulator properties of CdTe/HgTe/CdTe quantum wells are theoretically studied. The CdTe/HgTe/CdTe quantum well behaves as a topological insulator beyond a critical well width dimension. It is shown that if the barrier (CdTe) and well-region (HgTe) are altered by replacing them with the alloy CdxHg1-xTe of various stoichiometries, the critical width can be changed. The critical quantum well width is shown to depend on temperature, applied stress, growth directions, and external electric fields. Based on these results, a novel device concept is proposed that allows to switch between a normal semiconducting and topological insulator state through application of moderate external electric fields.

  5. Focused ion beam (FIB) milling of electrically insulating specimens using simultaneous primary electron and ion beam irradiation

    International Nuclear Information System (INIS)

    Stokes, D J; Vystavel, T; Morrissey, F

    2007-01-01

    There is currently great interest in combining focused ion beam (FIB) and scanning electron microscopy technologies for advanced studies of polymeric materials and biological microstructures, as well as for sophisticated nanoscale fabrication and prototyping. Irradiation of electrically insulating materials with a positive ion beam in high vacuum can lead to the accumulation of charge, causing deflection of the ion beam. The resultant image drift has significant consequences upon the accuracy and quality of FIB milling, imaging and chemical vapour deposition. A method is described for suppressing ion beam drift using a defocused, low-energy primary electron beam, leading to the derivation of a mathematical expression to correlate the ion and electron beam energies and currents with other parameters required for electrically stabilizing these challenging materials

  6. Spin-related tunneling through a nanostructured electric-magnetic barrier on the surface of a topological insulator.

    Science.gov (United States)

    Wu, Zhenhua; Li, Jun

    2012-01-27

    We investigate quantum tunneling through a single electric and/or magnetic barrier on the surface of a three-dimensional topological insulator. We found that (1) the propagating behavior of electrons in such system exhibits a strong dependence on the direction of the incident electron wavevector and incident energy, giving the possibility to construct a wave vector and/or energy filter; (2) the spin orientation can be tuned by changing the magnetic barrier structure as well as the incident angles and energies.PACS numbers: 72.25.Dc; 73.20.-r; 73.23.-b; 75.70.-i.

  7. Electric control of emergent magnonic spin current and dynamic multiferroicity in magnetic insulators at finite temperatures

    Science.gov (United States)

    Wang, Xi-guang; Chotorlishvili, L.; Guo, Guang-hua; Berakdar, J.

    2018-04-01

    Conversion of thermal energy into magnonic spin currents and/or effective electric polarization promises new device functionalities. A versatile approach is presented here for generating and controlling open circuit magnonic spin currents and an effective multiferroicity at a uniform temperature with the aid of spatially inhomogeneous, external, static electric fields. This field applied to a ferromagnetic insulator with a Dzyaloshinskii-Moriya type coupling changes locally the magnon dispersion and modifies the density of thermally excited magnons in a region of the scale of the field inhomogeneity. The resulting gradient in the magnon density can be viewed as a gradient in the effective magnon temperature. This effective thermal gradient together with local magnon dispersion result in an open-circuit, electric field controlled magnonic spin current. In fact, for a moderate variation in the external electric field the predicted magnonic spin current is on the scale of the spin (Seebeck) current generated by a comparable external temperature gradient. Analytical methods supported by full-fledge numerics confirm that both, a finite temperature and an inhomogeneous electric field are necessary for this emergent non-equilibrium phenomena. The proposal can be integrated in magnonic and multiferroic circuits, for instance to convert heat into electrically controlled pure spin current using for example nanopatterning, without the need to generate large thermal gradients on the nanoscale.

  8. Quantum oscillations in insulators with neutral Fermi surfaces

    Science.gov (United States)

    Sodemann, Inti; Chowdhury, Debanjan; Senthil, T.

    2018-02-01

    We develop a theory of quantum oscillations in insulators with an emergent Fermi sea of neutral fermions minimally coupled to an emergent U(1 ) gauge field. As pointed out by Motrunich [Phys. Rev. B 73, 155115 (2006), 10.1103/PhysRevB.73.155115], in the presence of a physical magnetic field the emergent magnetic field develops a nonzero value leading to Landau quantization for the neutral fermions. We focus on the magnetic field and temperature dependence of the analog of the de Haas-van Alphen effect in two and three dimensions. At temperatures above the effective cyclotron energy, the magnetization oscillations behave similarly to those of an ordinary metal, albeit in a field of a strength that differs from the physical magnetic field. At low temperatures, the oscillations evolve into a series of phase transitions. We provide analytical expressions for the amplitude and period of the oscillations in both of these regimes and simple extrapolations that capture well their crossover. We also describe oscillations in the electrical resistivity of these systems that are expected to be superimposed with the activated temperature behavior characteristic of their insulating nature and discuss suitable experimental conditions for the observation of these effects in mixed-valence insulators and triangular lattice organic materials.

  9. Depolarization current relaxation process of insulating dielectrics after corona poling under different charging conditions

    Directory of Open Access Journals (Sweden)

    J. W. Zhang

    2017-10-01

    Full Text Available As an insulating dielectric, polyimide is favorable for the application of optoelectronics, electrical insulation system in electric power industry, insulating, and packaging materials in space aircraft, due to its excellent thermal, mechanical and electrical insulating stability. The charge storage profile of such insulating dielectric is utmost important to its application, when it is exposed to electron irradiation, high voltage corona discharge or other treatments. These treatments could induce changes in physical and chemical properties of treated samples. To investigate the charge storage mechanism of the insulating dielectrics after high-voltage corona discharge, the relaxation processes responsible for corona charged polyimide films under different poling conditions were analyzed by the Thermally Stimulated Discharge Currents method (TSDC. In the results of thermal relaxation process, the appearance of various peaks in TSDC spectra provided a deep insight into the molecular status in the dielectric material and reflected stored space charge relaxation process in the insulating polymers after corona discharge treatments. Furthermore, the different space charge distribution status under various poling temperature and different discharge voltage level were also investigated, which could partly reflect the influence of the ambiance condition on the functional dielectrics after corona poling.

  10. Depolarization current relaxation process of insulating dielectrics after corona poling under different charging conditions

    Science.gov (United States)

    Zhang, J. W.; Zhou, T. C.; Wang, J. X.; Yang, X. F.; Zhu, F.; Tian, L. M.; Liu, R. T.

    2017-10-01

    As an insulating dielectric, polyimide is favorable for the application of optoelectronics, electrical insulation system in electric power industry, insulating, and packaging materials in space aircraft, due to its excellent thermal, mechanical and electrical insulating stability. The charge storage profile of such insulating dielectric is utmost important to its application, when it is exposed to electron irradiation, high voltage corona discharge or other treatments. These treatments could induce changes in physical and chemical properties of treated samples. To investigate the charge storage mechanism of the insulating dielectrics after high-voltage corona discharge, the relaxation processes responsible for corona charged polyimide films under different poling conditions were analyzed by the Thermally Stimulated Discharge Currents method (TSDC). In the results of thermal relaxation process, the appearance of various peaks in TSDC spectra provided a deep insight into the molecular status in the dielectric material and reflected stored space charge relaxation process in the insulating polymers after corona discharge treatments. Furthermore, the different space charge distribution status under various poling temperature and different discharge voltage level were also investigated, which could partly reflect the influence of the ambiance condition on the functional dielectrics after corona poling.

  11. Evaluating electrically insulating films deposited on V-4% Cr-4% Ti by reactive CVD

    Energy Technology Data Exchange (ETDEWEB)

    Park, J.H.; Cho, W.D. [Argonne National Lab., IL (United States)

    1997-04-01

    Previous CaO coatings on V-4%Cr-4%Ti exhibited high-ohmic insulator behavior even though a small amount of vanadium from the alloy was incorporated in the coating. However, when the vanadium concentration in the coatings is > 15 wt%, the coating becomes conductive. When the vanadium concentration is high in localized areas, a calcium vanadate phase that exhibits semiconductor behavior can form. To explore this situation, CaO and Ca-V-O coatings were produced on vanadium alloys by chemical vapor deposition (CVD) and by a metallic-vapor process to investigate the electrical resistance of the coatings. Initially, the vanadium alloy specimens were either charged with oxygen in argon that contained trace levels of oxygen, or oxidized for 1.5-3 h in a 1% CO-CO{sub 2} gas mixture or in air to form vanadium oxide at 625-650{degrees}C. Most of the specimens were exposed to calcium vapor at 800-850{degrees}C. Initial and final weights were obtained to monitor each step, and surveillance samples were removed for examination by optical and scanning electron microscopy and electron-energy-dispersive and X-ray diffraction analysis; the electrical resistivity was also measured. The authors found that Ca-V-O films exhibited insulator behavior when the ratio of calcium concentration to vanadium concentration R in the film was > 0.9, and semiconductor or conductor behavior for R < 0.8. However, in some cases, semiconductor behavior was observed when CaO-coated samples with R > 0.98 were exposed in liquid lithium. Based on these studies, the authors conclude that semiconductor behavior occurs if a conductive calcium vanadate phase is present in localized regions in the CaO coating.

  12. Sizing of the thermal and electrical systems for an FED bundle divertor design with MgO insulation

    International Nuclear Information System (INIS)

    Schultz, J.H.

    1981-01-01

    The high-order dependence of toroidal ripple from a bundle divertor on the magnet shield thickness increases the desirability of a magnet technology with minimal shielding requirements. A jacketed conductor with MgO powder insulation has been used successfully in highly irradiated environments. Its properties and limitations are described. A thermal and electrical sizing code has been developed for magnet design with this technology. Two design examples for ETF and FED missions show reduced recirculating power from previously reported designs

  13. Optimization of the vacuum insulator stack of the MIG pulsed power generator

    International Nuclear Information System (INIS)

    Khamzakhan, G; Chaikovsky, S A

    2014-01-01

    The MIG multi-purpose pulsed power machine is intended to generate voltage pulses of amplitude up to 6 MV with electron-beam loads and current pulses of amplitude up to 2.5 MA and rise time '00 ns with inductive loads like Z pinches. The MIG generator is capable of producing a peak power of 2.5 TW. Its water transmission line is separated from the vacuum line by an insulator stack. In the existing design of the insulator, some malfunctions have been detected. The most serious problems revealed are the vacuum surface flashover occurring before the current peaks and the deep discharge traces on the water-polyethylene interface of the two rings placed closer to the ground. A comprehensive numerical simulation of the electric field distribution in the insulator of the MIG generator has been performed. It has been found that the chief drawbacks are nonuniform voltage grading across the insulator rings and significant enhancement of the electric field at anode triple junctions. An improved design of the insulator stack has been developed. It is expected that the proposed modification that requires no rearrangement of either the water line or the load-containing vacuum chamber will provide higher electric strength of the insulator

  14. Development and preliminary experimental study on micro-stacked insulator

    International Nuclear Information System (INIS)

    Ren Chengyan; Yuan Weiqun; Zhang Dongdong; Yan Ping; Wang Jue

    2009-01-01

    High gradient insulating technology is one of the key technologies in new type dielectric wall accelerator(DWA). High gradient insulator, namely micro-stacked insulator, was developed and preliminary experimental study was done. Based on the finite element and particle simulating method, surface electric field distribution and electron movement track of micro-stacked insulator were numerated, and then the optimized design proposal was put forward. Using high temperature laminated method, we developed micro-stacked insulator samples which uses exhaustive fluorinated ethylene propylene(FEP) as dielectric layer and stainless steel as metal layer. Preliminary experiment of vacuum surface flashover in nanosecond pulse voltage was done and micro-stacked insulator exhibited favorable vacuum surface flashover performance with flashover field strength of near 180 kV/cm. (authors)

  15. Thin-film composite materials as a dielectric layer for flexible metal-insulator-metal capacitors.

    Science.gov (United States)

    Tiwari, Jitendra N; Meena, Jagan Singh; Wu, Chung-Shu; Tiwari, Rajanish N; Chu, Min-Ching; Chang, Feng-Chih; Ko, Fu-Hsiang

    2010-09-24

    A new organic-organic nanoscale composite thin-film (NCTF) dielectric has been synthesized by solution deposition of 1-bromoadamantane and triblock copolymer (Pluronic P123, BASF, EO20-PO70-EO20), in which the precursor solution has been achieved with organic additives. We have used a sol-gel process to make a metal-insulator-metal capacitor (MIM) comprising a nanoscale (10 nm-thick) thin-film on a flexible polyimide (PI) substrate at room temperature. Scanning electron microscope and atomic force microscope revealed that the deposited NCTFs were crack-free, uniform, highly resistant to moisture absorption, and well adhered on the Au-Cr/PI. The electrical properties of 1-bromoadamantane-P123 NCTF were characterized by dielectric constant, capacitance, and leakage current measurements. The 1-bromoadamantane-P123 NCTF on the PI substrate showed a low leakage current density of 5.5 x 10(-11) A cm(-2) and good capacitance of 2.4 fF at 1 MHz. In addition, the calculated dielectric constant of 1-bromoadamantane-P123 NCTF was 1.9, making them suitable candidates for use in future flexible electronic devices as a stable intermetal dielectric. The electrical insulating properties of 1-bromoadamantane-P123 NCTF have been improved due to the optimized dipole moments of the van der Waals interactions.

  16. Design of the Yang magnetically-insulated transmission line

    International Nuclear Information System (INIS)

    Gu Yuanchao; Song Shenyi

    2002-01-01

    The authors have designed a new magnetically insulated transmission line (MITL) for the Yang accelerator. The differences between the existing line and the designing one are given. The electric strength of some special regions on the lines and the inductance of the lines have been calculated. The authors have checked the states of magnetic insulation on the designing line

  17. Study of heat transfer in superconducting cable electrical insulation of accelerator magnet cooled by superfluid helium; Etude des transferts de chaleur dans les isolations electriques de cables supraconducteurs d'aimant d'accelerateur refroidi par helium superfluide

    Energy Technology Data Exchange (ETDEWEB)

    Baudouy, B

    1996-10-04

    Heat transfer studies of electrical cable insulation in superconducting winding are of major importance for stability studies in superconducting magnets. This work presents an experimental heat transfer study in superconducting cables of Large Hadron Collider dipoles cooled by superfluid helium and submitted to volume heat dissipation due to beam losses. For NbTi magnets cooled by superfluid helium the most severe heat barrier comes from the electrical insulation of the cables. Heat behaviour of a winding is approached through an experimental model in which insulation characteristics can be modified. Different tests on insulation patterns show that heat transfer is influenced by superfluid helium contained in insulation even for small volume of helium (2 % of cable volume). Electrical insulation can be considered as a composite material made of a solid matrix with a helium channels network which cannot be modelled easily. This network is characterised by another experimental apparatus which allows to study transverse and steady-state heat transfer through an elementary insulation pattern. Measurements in Landau regime ({delta}T{approx}10{sup -5} to 10{sup -3} K) and in Gorter-Mellink regime ({delta}T>10{sup -3} K) and using assumptions that helium thermal paths and conduction in the insulation are decoupled allow to determine an equivalent channel area (10{sup -6} m{sup 2}) and an equivalent channel diameter (25 {mu}). (author)

  18. Effects of γ-radiation on the properties of insulating oil

    International Nuclear Information System (INIS)

    Abdel Aziz, M.M.; Elshazly-Zaghloul, M.; Zaghloul, A.R.M.; Fikry, L.; Raieh, M.

    1986-01-01

    Electrical Equipment used in an irradiated environment suffer from ionization and other effects. Insulating oil, e.g. of transformers, in a nuclear power station is subjected to γ-radiation. In this communication we provide a detailed experimental study of insulating oil subjected to γ-radiation. Unused oil samples of the type used in Egypt were subjected to γ-radiation for different time periods. The electrical properties of these samples are measured; dielectric constant and breakdown strength

  19. Growth of semi-insulating InP through nuclear doping

    International Nuclear Information System (INIS)

    Aliyev, M.I; Rashidova, Sh.Sh; Huseynli, M.A.

    2012-01-01

    Full text : Semi-insulating semiconductors are widely used in so-called dielectronics. Dielectric devices have quick response, good frequency characteristics, a low noise level, low sensitivity to temperature changes, etc. One of the most promising semiconductor materials is InP. At present annealing and doping are commonly used techniques to grow semi-insulating InP. The aim of this work was to grow semi-insulating InP through nuclear doping (by irradiation with gamma-quanta). InP single crystals were obtained by Czochralski method. Specimens were irradiated with doses of 10kGr at room temperature. Electrical conductivity and Hall effect were measured before and after irradiation in the temperature range 77 to 320K. After irradiation reduction in electrical conductivity was observed. This fact can be associated with formation of M-centers in positively threefold charged states of vacancy and antisite defects. Under irradiation first Ini interstitial atoms and phosphorus vacancies form. Further, the Ini atoms occupy the phosphorus vacancies. As a result there appear InP antiste defects, which along with indium vacancies form V I nI n p + In p + + complexes of the acceptor type. These complexes turn out to be traps for charge carriers and electrical conductivity of irradiated InP are sharply reduced to semi-insulating specimens

  20. Electric-field induced spin accumulation in the Landau level states of topological insulator thin films

    Science.gov (United States)

    Siu, Zhuo Bin; Chowdhury, Debashree; Basu, Banasri; Jalil, Mansoor B. A.

    2017-08-01

    A topological insulator (TI) thin film differs from the more typically studied thick TI system in that the former has both a top and a bottom surface where the states localized at both surfaces can couple to one other across the finite thickness. An out-of-plane magnetic field leads to the formation of discrete Landau level states in the system, whereas an in-plane magnetization breaks the angular momentum symmetry of the system. In this work, we study the spin accumulation induced by the application of an in-plane electric field to the TI thin film system where the Landau level states and inter-surface coupling are simultaneously present. We show, via Kubo formula calculations, that the in-plane spin accumulation perpendicular to the magnetization due to the electric field vanishes for a TI thin film with symmetric top and bottom surfaces. A finite in-plane spin accumulation perpendicular to both the electric field and magnetization emerges upon applying either a differential magnetization coupling or a potential difference between the two film surfaces. This spin accumulation results from the breaking of the antisymmetry of the spin accumulation around the k-space equal-energy contours.

  1. Electricity Breakdown Management for Sarawak Energy: Use of Condition-Based Equipment for Detection of Defective Insulator

    Science.gov (United States)

    Tan, J. K.; Abas, N.

    2017-07-01

    Managing electricity breakdown is vital since an outage causes economic losses for customers and the utility companies. However, electricity breakdown is unavoidable due to some internal or external factors beyond our control. Electricity breakdown on overhead lines tend occur more frequently because it is prone to external disturbances such as animal, overgrown vegetation and defective pole top accessories. In Sarawak Energy Berhad (SEB), majority of the network are composed of overhead lines and hence, is more prone to failure. Conventional method of equipment inspection and fault finding are not effective to quickly identify the root cause of failure. SEB has engaged the use of corona discharge camera as condition-based monitoring equipment to carry out condition based inspection on the line in order to diagnose the condition of the lines prior to failure. Experimental testing has been carried out to determine the correlation between the corona discharge count and the level of defect on line insulator. The result shall be tabulated and will be used as reference for future scanning and diagnostic on any defect on the lines.

  2. Bonded stacked-ring insulator for the Antares electron gun

    International Nuclear Information System (INIS)

    Stine, R.D.; Allen, G.R.; Eaton, E.; Weinstein, B.

    1982-01-01

    A large diameter insulator utilizing epoxy bonding which has sufficient mechanical strength to support the 3000 kg cathode/grid assembly was developed. Bonding the insulator simplifies the handling and reduces the number of 0-ring seals to a minimum. We have described the material selection, bonding techniques and electrical design approach

  3. Specular Andreev reflection in thin films of topological insulators

    Science.gov (United States)

    Majidi, Leyla; Asgari, Reza

    2016-05-01

    We theoretically reveal the possibility of specular Andreev reflection in a thin film topological insulator normal-superconductor (N/S) junction in the presence of a gate electric field. The probability of specular Andreev reflection increases with the electric field, and electron-hole conversion with unit efficiency happens in a wide experimentally accessible range of the electric field. We show that perfect specular Andreev reflection can occur for all angles of incidence with a particular excitation energy value. In addition, we find that the thermal conductance of the structure displays exponential dependence on the temperature. Our results reveal the potential of the proposed topological insulator thin-film-based N/S structure for the realization of intraband specular Andreev reflection.

  4. Insulating Foams Save Money, Increase Safety

    Science.gov (United States)

    2009-01-01

    Scientists at Langley Research Center created polyimide foam insulation for reusable cryogenic propellant tanks on the space shuttle. Meanwhile, a small Hialeah, Florida-based business, PolyuMAC Inc., was looking for advanced foams to use in the customized manufacturing of acoustical and thermal insulation. The company contacted NASA, licensed the material, and then the original inventors worked with the company's engineers to make a new material that was better for both parties. The new version, a high performance, flame retardant, flexible polyimide foam, is used for insulating NASA cryogenic propellant tanks and shows promise for use on watercraft, aircraft, spacecraft, electronics and electrical products, automobiles and automotive products, recreation equipment, and building and construction materials.

  5. Electric organ discharges and electric images during electrolocation

    Science.gov (United States)

    Assad, C.; Rasnow, B.; Stoddard, P. K.

    1999-01-01

    Weakly electric fish use active electrolocation - the generation and detection of electric currents - to explore their surroundings. Although electrosensory systems include some of the most extensively understood circuits in the vertebrate central nervous system, relatively little is known quantitatively about how fish electrolocate objects. We believe a prerequisite to understanding electrolocation and its underlying neural substrates is to quantify and visualize the peripheral electrosensory information measured by the electroreceptors. We have therefore focused on reconstructing both the electric organ discharges (EODs) and the electric images resulting from nearby objects and the fish's exploratory behaviors. Here, we review results from a combination of techniques, including field measurements, numerical and semi-analytical simulations, and video imaging of behaviors. EOD maps are presented and interpreted for six gymnotiform species. They reveal diverse electric field patterns that have significant implications for both the electrosensory and electromotor systems. Our simulations generated predictions of the electric images from nearby objects as well as sequences of electric images during exploratory behaviors. These methods are leading to the identification of image features and computational algorithms that could reliably encode electrosensory information and may help guide electrophysiological experiments exploring the neural basis of electrolocation.

  6. Proceedings of the second meeting on electrical insulators for fusion magnets

    International Nuclear Information System (INIS)

    1983-07-01

    To guide the formulation of this program, nineteen speakers generally representing the magnet community - manufacturers, designers, and materials people - met and presented a series of talks in six sessions. Sessions topics included: magnet insulator environment, current testing activities, irradiation sources, failure modes, test parameters, and insulator design. Each presentation was discussed by the meeting, at-large, and the concensus opinions of these discussions were noted. After the conclusion of the talks, the meeting was subdivided into four subcommittees to consider and make recommendations on the following topics: irradiation facilities and dosimetry, insulator compositions and specimen sizes and shapes, test procedures and equipment, and specimen loads, influence of magnet mechanical and thermal cycles on test program, and international cooperation

  7. Spin-transport-phenomena in metals, semiconductors, and insulators

    Energy Technology Data Exchange (ETDEWEB)

    Althammer, Matthias Klaus

    2012-07-19

    Assuming that one could deterministically inject, transport, manipulate, store and detect spin information in solid state devices, the well-established concepts of charge-based electronics could be transferred to the spin realm. This thesis explores the injection, transport, manipulation and storage of spin information in metallic conductors, semiconductors, as well as electrical insulators. On the one hand, we explore the spin-dependent properties of semiconducting zinc oxide thin films deposited via laser-molecular beam epitaxy (laser-MBE). After demonstrating that the zinc oxide films fabricated during this thesis have excellent structural, electrical, and optical properties, we investigate the spin-related properties by optical pump/probe, electrical injection/optical detection, and all electrical spin valve-based experiments. The two key results from these experiments are: (i) Long-lived spin states with spin dephasing times of 10 ns at 10 K related to donor bound excitons can be optically addressed. (ii) The spin dephasing times relevant for electrical transport-based experiments are {<=} 2 ns at 10 K and are correlated with structural quality. On the other hand we focus on two topics of current scientific interest: the comparison of the magnetoresistance to the magnetothermopower of conducting ferromagnets, and the investigation of pure spin currents generated in ferromagnetic insulator/normal metal hybrid structures. We investigate the magnetoresistance and magnetothermopower of gallium manganese arsenide and Heusler thin films as a function of external magnetic field orientation. Using a series expansion of the resistivity and Seebeck tensors and the inherent symmetry of the sample's crystal structure, we show that a full quantitative extraction of the transport tensors from such experiments is possible. Regarding the spin currents in ferromagnetic insulator/normal metal hybrid structures we studied the spin mixing conductance in yttrium iron garnet

  8. Effect of electric field configuration on streamer and partial discharge phenomena in a hydrocarbon insulating liquid under AC stress

    International Nuclear Information System (INIS)

    Liu, Z; Liu, Q; Wang, Z D

    2016-01-01

    This paper concerns pre-breakdown phenomena, including streamer characteristics from a fundamental perspective and partial discharge (PD) measurements from an industrial perspective, in a hydrocarbon insulating liquid. The aim was to investigate the possible changes of the liquid’s streamer and PD characteristics and their correlations when the uniformity of the AC electric field varies. In the experiments, a plane-to-plane electrode system incorporating a needle protrusion was used in addition to a needle-to-plane electrode system. When the applied electric field became more uniform, fewer radial branches occurred and streamer propagation towards the ground electrode was enhanced. The transition from streamer propagation dominated breakdown in divergent fields to streamer initiation dominated breakdown in uniform fields was evidenced. Relationships between streamer and PD characteristics were established, which were found to be electric field dependent. PD of the same apparent charge would indicate longer streamers if the electric field is more uniform. (paper)

  9. 18 CFR 39.4 - Funding of the Electric Reliability Organization.

    Science.gov (United States)

    2010-04-01

    ... CERTIFICATION OF THE ELECTRIC RELIABILITY ORGANIZATION; AND PROCEDURES FOR THE ESTABLISHMENT, APPROVAL, AND ENFORCEMENT OF ELECTRIC RELIABILITY STANDARDS § 39.4 Funding of the Electric Reliability Organization. (a) Any... Reliability Organization. 39.4 Section 39.4 Conservation of Power and Water Resources FEDERAL ENERGY...

  10. A Difference in Using Atomic Layer Deposition or Physical Vapour Deposition TiN as Electrode Material in Metal-Insulator-Metal and Metal-Insulator-Silicon Capacitors

    NARCIS (Netherlands)

    Groenland, A.W.; Wolters, Robertus A.M.; Kovalgin, Alexeij Y.; Schmitz, Jurriaan

    2011-01-01

    In this work, metal-insulator-metal (MIM) and metal-insulator-silicon (MIS) capacitors are studied using titanium nitride (TiN) as the electrode material. The effect of structural defects on the electrical properties on MIS and MIM capacitors is studied for various electrode configurations. In the

  11. Insulating oil, electrical for transformers and switches : a national standard of Canada; 5. ed.

    Energy Technology Data Exchange (ETDEWEB)

    Paniri, S; Burford, G; Martin, A; Adragna, M [eds.

    1997-09-01

    Standard specifications for insulating oil used in power transformers, instrument transformers, bushings, bulk oil circuit breakers, oil circuit reclosers, and switches were provided. The specifications are divided into Class A and Class B depending on the requirement for kinematic viscosity at -40 degrees C. A Class S oil is also introduced for oil circuit breakers. The standards were prepared by the Technical Committee on Transformer and Switch Oils under the jurisdiction of the Steering Committee on Electrical Engineering, and has been formally approved by these committees. It has been also approved as a National Standard of Canada by the Standards Council of Canada. The document provides a list of reference publications, describes the samples and test procedures, properties and delivery requirements. 1 tab.

  12. Ground-fault protection of insulated high-voltage power networks in mines

    Energy Technology Data Exchange (ETDEWEB)

    Pudelko, H

    1976-09-01

    Safety of power networks is discussed in underground black coal mines in Poland. Safety in mines with a long service life was compared with safety in mines constructed since 1950. Power networks and systems protecting against electric ground-faults in the 2 mine groups are comparatively evaluated. Systems for protection against electric ground-faults in mine high-voltage networks with an insulated star point of the transformer are characterized. Fluctuations of resistance of electrical insulation under conditions of changing load are analyzed. The results of analyses are given in 14 diagrams. Recommendations for design of systems protecting against electric ground-faults in 6 kV mine power systems are made. 7 references.

  13. High-Temperature Electrical Insulation Behavior of Alumina Films Prepared at Room Temperature by Aerosol Deposition and Influence of Annealing Process and Powder Impurities

    Science.gov (United States)

    Schubert, Michael; Leupold, Nico; Exner, Jörg; Kita, Jaroslaw; Moos, Ralf

    2018-04-01

    Alumina (Al2O3) is a widely used material for highly insulating films due to its very low electrical conductivity, even at high temperatures. Typically, alumina films have to be sintered far above 1200 °C, which precludes the coating of lower melting substrates. The aerosol deposition method (ADM), however, is a promising method to manufacture ceramic films at room temperature directly from the ceramic raw powder. In this work, alumina films were deposited by ADM on a three-electrode setup with guard ring and the electrical conductivity was measured between 400 and 900 °C by direct current measurements according to ASTM D257 or IEC 60093. The effects of film annealing and of zirconia impurities in the powder on the electrical conductivity were investigated. The conductivity values of the ADM films correlate well with literature data and can even be improved by annealing at 900 °C from 4.5 × 10-12 S/cm before annealing up to 5.6 × 10-13 S/cm after annealing (measured at 400 °C). The influence of zirconia impurities is very low as the conductivity is only slightly elevated. The ADM-processed films show a very good insulation behavior represented by an even lower electrical conductivity than conventional alumina substrates as they are commercially available for thick-film technology.

  14. 78 FR 29209 - Revisions to Electric Reliability Organization Definition of Bulk Electric System and Rules of...

    Science.gov (United States)

    2013-05-17

    ... Commission 18 CFR Part 40 Revisions to Electric Reliability Organization Definition of Bulk Electric System... local distribution'' as set forth in the Federal Power Act (FPA). \\1\\ Revisions to Electric Reliability... Reliability Organization Definition of Bulk Electric System, Order No. 743, 133 FERC ] 61,150, at P 16 (2010...

  15. Report of the 13th IEA workshop on radiation effects in ceramic insulators

    International Nuclear Information System (INIS)

    2004-03-01

    The 13th IEA Workshop on Radiation Effects in Ceramic Insulators, based on Annex II: Experimentation on Radiation Damage in Fusion Materials, to the IEA Implementing Agreement for a Programme of Research and Development on Radiation Damage in Fusion Materials, was held on the 9th, December, 2003, at Kyoto International Conference Center, in Kyoto, Japan, in conjunction with the 11th International Conference on Fusion Reactor Materials (ICFRM-11). 44 participants from 10 countries (26 from Japan, 5 from Spain, 3 from Belgium, 3 from USA, 2 from RF, each 1 from Austria, Greece, Italy, Romania, and UK) gathered together and discussed following issues extensively, with the newest experimental results, after the welcome remarks by one of the organizer and chairpersons, Dr. E.R. Hodgson of CIEMAT. Effects of electric field on radiation induced microstructural evolution, parasitic electrical current and voltage induced in cables and wires by radiation effects, optical materials, IFMIF related issues and fundamental aspects were discussed. Significant results such as an observation of γ-alumina and aluminum colloid formation for the Radiation Induced Electrical Degradation mechanism are obtained. This report is workshop summary, abstracts and documents of the 13th IEA Workshop on Radiation Effects in Ceramic Insulators. (author)

  16. Fermi surfaces in Kondo insulators

    Science.gov (United States)

    Liu, Hsu; Hartstein, Máté; Wallace, Gregory J.; Davies, Alexander J.; Ciomaga Hatnean, Monica; Johannes, Michelle D.; Shitsevalova, Natalya; Balakrishnan, Geetha; Sebastian, Suchitra E.

    2018-04-01

    We report magnetic quantum oscillations measured using torque magnetisation in the Kondo insulator YbB12 and discuss the potential origin of the underlying Fermi surface. Observed quantum oscillations as well as complementary quantities such as a finite linear specific heat capacity in YbB12 exhibit similarities with the Kondo insulator SmB6, yet also crucial differences. Small heavy Fermi sections are observed in YbB12 with similarities to the neighbouring heavy fermion semimetallic Fermi surface, in contrast to large light Fermi surface sections in SmB6 which are more similar to the conduction electron Fermi surface. A rich spectrum of theoretical models is suggested to explain the origin across different Kondo insulating families of a bulk Fermi surface potentially from novel itinerant quasiparticles that couple to magnetic fields, yet do not couple to weak DC electric fields.

  17. Acoustic insulator for combined well equipment of acoustic and radioactivity logging

    International Nuclear Information System (INIS)

    Arkad'ev, E.A.; Gorbachev, Yu.I.; Dseban', I.P.; Yagodov, G.I.

    1977-01-01

    The design of an acoustic insulator for cobined well equipment of acoustic and radioactivity logaing made on the basis of studying the velocity of elastic waves propagation and attenuation in cable structures of various marks is described. It is shown that the cable probe of electric loggign equipment which is recommended as an acoustic insulator for combined well equipment has the necessary sound-insulating properties

  18. Spin- and valley-dependent electrical conductivity of ferromagnetic group-IV 2D sheets in the topological insulator phase

    Science.gov (United States)

    Hoi, Bui Dinh; Yarmohammadi, Mohsen; Mirabbaszadeh, Kavoos; Habibiyan, Hamidreza

    2018-03-01

    In this work, based on the Kubo-Greenwood formalism and the k . p Hamiltonian model, the impact of Rashba spin-orbit coupling on electronic band structure and electrical conductivity of spin-up and spin-down subbands in counterparts of graphene, including silicene, stanene, and germanene nanosheets has been studied. When Rashba coupling is considered, the effective mass of Dirac fermions decreases significantly and no significant change is caused by this coupling for the subband gaps. All these nanosheets are found to be in topological insulator quantum phase at low staggered on-site potentials due to the applied perpendicular external electric field. We point out that the electrical conductivity of germanene increases gradually with Rashab coupling, while silicene and stanene have some fluctuations due to their smaller Fermi velocity. Furthermore, some critical temperatures with the same electrical conductivity values for jumping to the higher energy levels are observed at various Rashba coupling strengths. For all structures, a broad peak appears at low temperatures in electrical conductivity curves corresponding to the large entropy of systems when the thermal energy reaches to the difference between the energy states. Finally, we have reported that silicene has the larger has the larger electrical conductivity than two others.

  19. Development mineral insulated cables for nuclear instrumentation of reactors

    International Nuclear Information System (INIS)

    Calvo, W.A.P.; Hess Junior, A.; Brito Maciel, R. de

    1990-01-01

    In-core and out-of-core neutron detectors for reactor and safety control systems are usually connected by means of mineral insulated cables. The electrical signal, either a pulse or a current, is transmitted along the cable at high temperature, pressure and radiation and should not be influenced by electromagnetic interfereces from the environment. In this paper it is presented the result of the analysis of the mechanical and electrical properties of several types of mineral insulated cables and also the design, manufacture, sealing, cable ends and their applications to nuclear detectors of various types. (author) [pt

  20. Biodegradation performance of environmentally-friendly insulating oil

    Science.gov (United States)

    Yang, Jun; He, Yan; Cai, Shengwei; Chen, Cheng; Wen, Gang; Wang, Feipeng; Fan, Fan; Wan, Chunxiang; Wu, Liya; Liu, Ruitong

    2018-02-01

    In this paper, biodegradation performance of rapeseed insulating oil (RDB) and FR3 insulating oil (FR3) was studied by means of ready biodegradation method which was performed with Organization for Economic Co-operation and Development (OECD) 301B. For comparison, the biodegradation behaviour of 25# mineral insulating oil was also characterized with the same method. The testing results shown that the biodegradation degree of rapeseed insulating oil, FR3 insulating oil and 25# mineral insulating oil was 95.8%, 98.9% and 38.4% respectively. Following the “new chemical risk assessment guidelines” (HJ/T 154 - 2004), which illustrates the methods used to identify and assess the process safety hazards inherent. The guidelines can draw that the two vegetable insulating oils, i.e. rapeseed insulating oil and FR3 insulating oil are easily biodegradable. Therefore, the both can be classified as environmentally-friendly insulating oil. As expected, 25# mineral insulating oil is hardly biodegradable. The main reason is that 25# mineral insulating oil consists of isoalkanes, cyclanes and a few arenes, which has few unsaturated bonds. Biodegradation of rapeseed insulating oil and FR3 insulating oil also remain some difference. Biodegradation mechanism of vegetable insulating oil was revealed from the perspective of hydrolysis kinetics.

  1. Status of surface conduction in topological insulators

    International Nuclear Information System (INIS)

    Barua, Sourabh; Rajeev, K. P.

    2014-01-01

    In this report, we scrutinize the thickness dependent resistivity data from the recent literature on electrical transport measurements in topological insulators. A linear increase in resistivity with increase in thickness is expected in the case of these materials since they have an insulating bulk and a conducting surface. However, such a trend is not seen in the resistivity versus thickness data for all the cases examined, except for some samples, where it holds for a range of thickness

  2. Electrical Detection of Spin-to-Charge Conversion in a Topological Insulator Bi2Te3

    Science.gov (United States)

    Li, Connie H.; van't Erve, Olaf M. J.; Li, Yaoyi; Li, Lian; Jonker, Berry T.

    Spin-momentum locking in topological insulators (TIs) dictates that an unpolarized charge current creates a net spin polarization. We recently demonstrated the first electrical detection of this spontaneous polarization in a transport geometry, using a ferromagnetic (FM) / tunnel barrier contact, where the projection of the TI surface state spin on the magnetization of detector is measured as a voltage [1]. Alternatively, if spins are injected into the TI surface state system, it is distinctively associated with a unique carrier momentum, and hence should generated a charge accumulation, similar to that of inverse spin Hall effect. Here we experimentally demonstrate both effects in the same device fabricated in Bi2Te3: the electrical detection of the spin accumulation generated by an unpolarized current flowing through the surface states, and that of the charge accumulation generated by spins injected into the surface states system. This reverse measurement is an independent confirmation of spin-momentum locking in the TI surface states, and offers additional avenue for spin manipulation. It further demonstrates the robustness and versatility of electrical access to the TI surface state spin system, an important step towards its utilization in TI-based spintronics devices. C.H. Li et al., Nat. Nanotech. 9, 218 (2014). Supported by NRL core funds and Nanoscience Institute.

  3. Estimation of carrier mobility at organic semiconductor/insulator interface using an asymmetric capacitive test structure

    Directory of Open Access Journals (Sweden)

    Rajesh Agarwal

    2016-04-01

    Full Text Available Mobility of carriers at the organic/insulator interface is crucial to the performance of organic thin film transistors. The present work describes estimation of mobility using admittance measurements performed on an asymmetric capacitive test structure. Besides the advantage of simplicity, it is shown that at low frequencies, the measured capacitance comes from a large area of channel making the capacitance-voltage characteristics insensitive to contact resistances. 2-D numerical simulation and experimental results obtained with Pentacene/Poly(4-vinyphenol system are presented to illustrate the operation and advantages of the proposed technique.

  4. Microstructural characterization of XLPE electrical insulation in power cables: determination of void size distributions using TEM

    International Nuclear Information System (INIS)

    Markey, L; Stevens, G C

    2003-01-01

    In an effort to progress in our understanding of the ageing mechanisms of high voltage cables submitted to electrical and thermal stresses, we present a quantitative study of voids, the defects which are considered to be partly responsible for cable failure. We propose a method based on large data sets of transmission electron microscopy (TEM) observations of replicated samples allowing for the determination of void concentration distribution as a function of void size in the mesoscopic to microscopic range at any point in the cable insulation. A theory is also developed to calculate the effect of etching on the apparent size of the voids observed. We present the first results of this sort ever obtained on two industrial cables, one of which was aged in an AC field. Results clearly indicate that a much larger concentration of voids occur near the inner semiconductor compared to the bulk of the insulation, independently of ageing. An effect of ageing can also be seen near the inner semiconductor, resulting in an increase in the total void internal surface area and a slight shift of the concentration curve towards larger voids, with the peak moving from about 40 nm to about 50 nm

  5. Inverse participation ratio and localization in topological insulator phase transitions

    International Nuclear Information System (INIS)

    Calixto, M; Romera, E

    2015-01-01

    Fluctuations of Hamiltonian eigenfunctions, measured by the inverse participation ratio (IPR), turn out to characterize topological-band insulator transitions occurring in 2D Dirac materials like silicene, which is isostructural with graphene but with a strong spin–orbit interaction. Using monotonic properties of the IPR, as a function of a perpendicular electric field (which provides a tunable band gap), we define topological-like quantum numbers that take different values in the topological-insulator and band-insulator phases. (paper)

  6. The Role of Interfaces in Polyethylene/Metal-Oxide Nanocomposites for Ultrahigh-Voltage Insulating Materials.

    Science.gov (United States)

    Pourrahimi, Amir Masoud; Olsson, Richard T; Hedenqvist, Mikael S

    2018-01-01

    Recent progress in the development of polyethylene/metal-oxide nanocomposites for extruded high-voltage direct-current (HVDC) cables with ultrahigh electric insulation properties is presented. This is a promising technology with the potential of raising the upper voltage limit in today's underground/submarine cables, based on pristine polyethylene, to levels where the loss of energy during electric power transmission becomes low enough to ensure intercontinental electric power transmission. The development of HVDC insulating materials together with the impact of the interface between the particles and the polymer on the nanocomposites electric properties are shown. Important parameters from the atomic to the microlevel, such as interfacial chemistry, interfacial area, and degree of particle dispersion/aggregation, are discussed. This work is placed in perspective with important work by others, and suggested mechanisms for improved insulation using nanoparticles, such as increased charge trap density, adsorption of impurities/ions, and induced particle dipole moments are considered. The effects of the nanoparticles and of their interfacial structures on the mechanical properties and the implications of cavitation on the electric properties are also discussed. Although the main interest in improving the properties of insulating polymers has been on the use of nanoparticles, leading to nanodielectrics, it is pointed out here that larger microscopic hierarchical metal-oxide particles with high surface porosity also impart good insulation properties. The impact of the type of particle and its inherent properties (purity and conductivity) on the nanocomposite dielectric and insulating properties are also discussed based on data obtained by a newly developed technique to directly observe the charge distribution on a nanometer scale in the nanocomposite. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  7. Thermal conductivity and Kapitza resistance of cyanate ester epoxy mix and tri-functional epoxy electrical insulations at superfluid helium temperature

    CERN Document Server

    Pietrowicz, S; Jones, S; Canfer, S; Baudouy, B

    2012-01-01

    In the framework of the European Union FP7 project EuCARD, two composite insulation systems made of cyanate ester epoxy mix and tri-functional epoxy (TGPAP-DETDA) with S-glass fiber have been thermally tested as possible candidates to be the electrical insulation of 13 T Nb$_{3}$Sn high field magnets under development for this program. Since it is expected to be operated in pressurized superfluid helium at 1.9 K and 1 atm, the thermal conductivity and the Kapitza resistance are the most important input parameters for the thermal design of this type of magnet and have been determined in this study. For determining these thermal properties, three sheets of each material with different thicknesses varying from 245 μm to 598 μm have been tested in steady-state condition in the temperature range of 1.6 K - 2.0 K. The thermal conductivity for the tri-functional epoxy (TGPAP-DETDA) epoxy resin insulation is found to be k=[(34.2±5.5).T-(16.4±8.2)]×10-3 Wm-1K-1 and for the cyanate ester epoxy k=[(26.8±4.8).T- (9...

  8. Degradation diagnosing method for low voltage electric wire and cable in nuclear facility

    International Nuclear Information System (INIS)

    Kamimura, Seiji; Seki, Ikuo; Yagyu, Hideki; Onishi, Takao; Kusama, Yasuo.

    1991-01-01

    A considerable skill is required for a visual inspection method which has been used most widely for determining the degradation of low voltage electric wires and cables used mostly in facilities such as nuclear power plants. It is extremely difficult to determine the degradation accurately and appropriately even for skilled inspectors because of individual difference. Then, a small amount of organic insulation materials is taken as a sample from insulators or sheath materials actually disposed. The pyrolytic temperature of the sample is measured by thermal gravimetric analysis to determine the extent of the degradation of the electric wire and cable based on the relationship between the degradation and the elongation. Since there is a close relationship between the temperature at which the measured weight of the sample is reduced by 5% and the degradation behavior of the mechanical property, analysis can be conducted effectively by an extremely small amount of the sample. Since the insulation degradation of relatively low voltage electric wires and cables can be determined in a non-destructive manner at high accuracy, the lifetime can be forecasted. (N.H.)

  9. Synthesis of ultrathin polymer insulating layers by initiated chemical vapour deposition for low-power soft electronics.

    Science.gov (United States)

    Moon, Hanul; Seong, Hyejeong; Shin, Woo Cheol; Park, Won-Tae; Kim, Mincheol; Lee, Seungwon; Bong, Jae Hoon; Noh, Yong-Young; Cho, Byung Jin; Yoo, Seunghyup; Im, Sung Gap

    2015-06-01

    Insulating layers based on oxides and nitrides provide high capacitance, low leakage, high breakdown field and resistance to electrical stresses when used in electronic devices based on rigid substrates. However, their typically high process temperatures and brittleness make it difficult to achieve similar performance in flexible or organic electronics. Here, we show that poly(1,3,5-trimethyl-1,3,5-trivinyl cyclotrisiloxane) (pV3D3) prepared via a one-step, solvent-free technique called initiated chemical vapour deposition (iCVD) is a versatile polymeric insulating layer that meets a wide range of requirements for next-generation electronic devices. Highly uniform and pure ultrathin films of pV3D3 with excellent insulating properties, a large energy gap (>8 eV), tunnelling-limited leakage characteristics and resistance to a tensile strain of up to 4% are demonstrated. The low process temperature, surface-growth character, and solvent-free nature of the iCVD process enable pV3D3 to be grown conformally on plastic substrates to yield flexible field-effect transistors as well as on a variety of channel layers, including organics, oxides, and graphene.

  10. Influence of water trees on breakdown voltage of polymeric cables insulations

    Energy Technology Data Exchange (ETDEWEB)

    Stancu, Cristina [INCDIE ICPE CA, Bucharest (Romania); Notingher, Petru V.; Plopeanu, Mihai Gabriel [Politehnica University of Bucharest, Bucharest (Romania)

    2011-07-01

    In a previous paper was shown that water trees development modifies considerably the electric field repartition, which increases significantly in the vicinity of treed areas. In order to find the water trees influence on the breakdown voltage, in the present paper, an experimental study on model cables insulated with low density polyethylene is done. In insulation samples, water trees with various dimensions and densities were developed. For the reduction of the test duration, an electric field with a higher frequency (3-5 kHz) was used. For breakdown voltage measurement an automatic setup was realized. For each value of the ageing time the dimensions and densities of water trees and breakdown voltage were measured and the dependency of the breakdown voltage with these quantities were analysed. The results show a significant reduction of the breakdown voltage of treed cables insulations compared to un-treed ones. Key words: polyethylene, water treeing, electric field, breakdown, power cables.

  11. Estimation of the diameter-charge distribution in polydisperse electrically charged sprays of electrically insulating liquids

    Energy Technology Data Exchange (ETDEWEB)

    Rigit, A.R.H. [University of Sarawak, Faculty of Engineering, Kota Samarahan, Sarawak (Malaysia); Shrimpton, John S. [University of Southampton, Energy Technology Research Group, School of Engineering Sciences, Southampton (United Kingdom)

    2009-06-15

    The majority of scientific and industrial electrical spray applications make use of sprays that contain a range of drop diameters. Indirect evidence suggests the mean drop diameter and the mean drop charge level are usually correlated. In addition, within each drop diameter class there is every reason to suspect a distribution of charge levels exist for a particular drop diameter class. This paper presents an experimental method that uses the joint PDF of drop velocity and diameter, obtained from phase Doppler anemometry measurements, and directly obtained spatially resolved distributions of the mass and charge flux to obtain a drop diameter and charge frequency distribution. The method is demonstrated using several data-sets obtained from experimental measurements of steady poly-disperse sprays of an electrically insulating liquid produced with the charge injection technique. The space charge repulsion in the spray plume produces a hollow cone spray structure. In addition an approximate self-similarity is observed, with the maximum radial mass and charge flow occurring at r/d{proportional_to}200. The charge flux profile is slightly offset from the mass flux profile, and this gives direct evidence that the spray specific charge increases from approximately 20% of the bulk mean spray specific charge on the spray axis to approximately 200% of the bulk mean specific charge in the periphery of the spray. The results from the drop charge estimation model suggest a complex picture of the correlation between drop charge and drop diameter, with spray specific charge, injection velocity and orifice diameter all contributing to the shape of the drop diameter-charge distribution. Mean drop charge as a function of the Rayleigh limit is approximately 0.2, and is invariant with drop diameter and also across the spray cases tested. (orig.)

  12. Estimation of the diameter-charge distribution in polydisperse electrically charged sprays of electrically insulating liquids

    Science.gov (United States)

    Rigit, A. R. H.; Shrimpton, John S.

    2009-06-01

    The majority of scientific and industrial electrical spray applications make use of sprays that contain a range of drop diameters. Indirect evidence suggests the mean drop diameter and the mean drop charge level are usually correlated. In addition, within each drop diameter class there is every reason to suspect a distribution of charge levels exist for a particular drop diameter class. This paper presents an experimental method that uses the joint PDF of drop velocity and diameter, obtained from phase Doppler anemometry measurements, and directly obtained spatially resolved distributions of the mass and charge flux to obtain a drop diameter and charge frequency distribution. The method is demonstrated using several data-sets obtained from experimental measurements of steady poly-disperse sprays of an electrically insulating liquid produced with the charge injection technique. The space charge repulsion in the spray plume produces a hollow cone spray structure. In addition an approximate self-similarity is observed, with the maximum radial mass and charge flow occurring at r/ d ~ 200. The charge flux profile is slightly offset from the mass flux profile, and this gives direct evidence that the spray specific charge increases from approximately 20% of the bulk mean spray specific charge on the spray axis to approximately 200% of the bulk mean specific charge in the periphery of the spray. The results from the drop charge estimation model suggest a complex picture of the correlation between drop charge and drop diameter, with spray specific charge, injection velocity and orifice diameter all contributing to the shape of the drop diameter-charge distribution. Mean drop charge as a function of the Rayleigh limit is approximately 0.2, and is invariant with drop diameter and also across the spray cases tested.

  13. MHD pressure drop of imperfect insulation of liquid metal flow

    International Nuclear Information System (INIS)

    Horiike, H.; Nishiura, R.; Inoue, S.; Miyazaki, K.

    2000-01-01

    An experiment was performed to study magnetohydrodynamic (MHD) pressure gradient in the case of an imperfect electric insulation coating when using NaK loop. Test channels with uniform defects in their coating were made by painting inner surface with acrylic lacquer insulation. It was found that the exponent to B -- which is 1 for insulated walls, and 2 for conducting ones, was very sensitive to crack fractions lower than 25%. The pressure gradient was found to increase almost linearly with the fraction

  14. Ultra-low-loss inverted taper coupler for silicon-on-insulator ridge waveguide

    DEFF Research Database (Denmark)

    Pu, Minhao; Liu, Liu; Ou, Haiyan

    2010-01-01

    An ultra-low-loss coupler for interfacing a silicon-on-insulator ridge waveguide and a single-mode fiber in both polarizations is presented. The inverted taper coupler, embedded in a polymer waveguide, is optimized for both the transverse-magnetic and transverse-electric modes through tapering...... the width of the silicon-on-insulator waveguide from 450 nm down to less than 15 nm applying a thermal oxidation process. Two inverted taper couplers are integrated with a 3-mm long silicon-on-insulator ridge waveguide in the fabricated sample. The measured coupling losses of the inverted taper coupler...... for transverse-magnetic and transverse-electric modes are ~0.36 dB and ~0.66 dB per connection, respectively....

  15. Improved thermal monitoring of rotating machine insulation

    International Nuclear Information System (INIS)

    Stone, G.C.; Sedding, H.G.; Bernstein, B.S.

    1991-01-01

    Aging of motor and generator insulation is most often induced as a result of operation at high temperatures. In spite of this knowledge, stator and rotor temperatures are only crudely monitored in existing machines. In EPRI project RP2577-1, three new means of detecting machine temperatures were successfully developed. Two of the techniques, the Electronic Rotor Temperature Sensor and the Passive Rotor Temperature Sensor, were specifically developed to give point temperature readings on turbine generator rotor windings. The Insulation Sniffer allows operators to determine when any electrical insulation in a motor is overheating. Another electronic device, called the Thermal Life Indicator, helps operators and maintenance personnel determine how accumulated operation has affected the remaining life of the insulation in rotating machines. These new devices permit nuclear station operators to avoid hazardous operating conditions and will help to determine priorities for maintenance and plant life extension programs

  16. Handleable shapes of thermal insulation material

    Energy Technology Data Exchange (ETDEWEB)

    Hughes, J. T.

    1989-01-17

    Handleable and machineable shapes of thermal insulation material are made by compacting finely divided thermal insulation material into the cells of a reinforcing honeycomb insulation material into the cells of a reinforcing honeycomb structure. The finely divided thermal insulation material may be, for example, silica aerogel, pyrogenic silica, carbon black, silica gel, volatilised silica, calcium silicate, vermiculate or perlite, or finely divided metal oxides such as alumina or titania. The finely divided thermal insulation material may include an infra-red opacifier and/or reinforcing fibres. The reinforcing honeycomb structure may be made from, for example, metals such as aluminium foil, inorganic materials such as ceramics, organic materials such as plastics materials, woven fabrics or paper. A rigidiser may be employed. The shapes of thermal insulation material are substantially rigid and may be machines, for example by mechanical or laser cutting devices, or may be formed, for example by rolling, into curved or other shaped materials. 12 figs.

  17. Limiting oxygen concentration for extinction of upward spreading flames over inclined thin polyethylene-insulated NiCr electrical wires with opposed-flow under normal- and micro-gravity

    KAUST Repository

    Hu, Longhua; Lu, Yong; Yoshioka, Kosuke; Zhang, Yangshu; Fernandez-Pello, Carlos; Chung, Suk-Ho; Fujita, Osamu

    2016-01-01

    . The experiments reported here used polyethylene (PE)-insulated (thickness of 0.15 mm) Nichrome (NiCr)-core (diameter of 0.5 mm) electrical wires. Limiting oxygen concentrations (LOC) at extinction were measured for upward spreading flame at various forced opposed-flow

  18. Improved DC Gun Insulator Assembly

    International Nuclear Information System (INIS)

    Neubauer, M.L.; Dudas, A.; Sah, R.; Poelker, M.; Surles-Law, K.E.L.

    2010-01-01

    Many user facilities such as synchrotron radiation light sources and free electron lasers require accelerating structures that support electric fields of 10-100 MV/m, especially at the start of the accelerator chain where ceramic insulators are used for very high gradient DC guns. These insulators are difficult to manufacture, require long commissioning times, and often exhibit poor reliability. Two technical approaches to solving this problem will be investigated. Firstly, inverted ceramics offer solutions for reduced gradients between the electrodes and ground. An inverted design will be presented for 350 kV, with maximum gradients in the range of 5-10 MV/m. Secondly, novel ceramic manufacturing processes will be studied, in order to protect triple junction locations from emission, by applying a coating with a bulk resistivity. The processes for creating this coating will be optimized to provide protection as well as be used to coat a ceramic with an appropriate gradient in bulk resistivity from the vacuum side to the air side of an HV standoff ceramic cylinder. Example insulator designs are being computer modelled, and insulator samples are being manufactured and tested

  19. Radiation resistant electrical bushing for high pressures and temperatures

    Energy Technology Data Exchange (ETDEWEB)

    Zajic, V; Banyr, J

    1980-11-15

    The bushing described is characterized by a hollow with a joining member provided inside of at least one of the bushing's electrically conductive core soldered or embedded into a bore in the insulator. Thus, the concentration is limited of the material of the electrically conductive core in the area of the soldered or embedded joint of the support of the electrically conductive core and the insulator, and the resulting force effect is reduced of the difference in thermal dilatations of the materials of the electrically conductive core and the insulator.

  20. Radiation resistant electrical bushing for high pressures and temperatures

    International Nuclear Information System (INIS)

    Zajic, V.; Banyr, J.

    1980-01-01

    The bushing described is characterized by a hollow with a joining member provided inside of at least one of the bushing's electrically conductive core soldered or embedded into a bore in the insulator. Thus, the concentration is limited of the material of the electrically conductive core in the area of the soldered or embedded joint of the support of the electrically conductive core and the insulator, and the resulting force effect is reduced of the difference in thermal dilatations of the materials of the electrically conductive core and the insulator. (J.B.)

  1. Optimization of electron beam crosslinking of wire and cable insulation

    International Nuclear Information System (INIS)

    Zimek, Zbigniew; Przybytniak, Grażyna; Nowicki, Andrzej

    2012-01-01

    The computer simulations based on Monte Carlo (MC) method and the ModeCEB software were carried out in connection with electron beam (EB) radiation set-up for crosslinking of electric wire and cable insulation. The theoretical predictions for absorbed dose distribution in irradiated electric insulation induced by scanned EB were compared to the experimental results of irradiation that was carried out in the experimental set-up based on ILU 6 electron accelerator with electron energy 0.5–2.0 MeV. The computer simulation of the dose distributions in two-sided irradiation system by a scanned electron beam in multilayer circular objects was performed for various process parameters, namely electric wire and cable geometry (thickness of insulation layers and copper wire diameter), type of polymer insulation, electron energy, energy spread and geometry of electron beam, electric wire and cable layout in irradiation zone. The geometry of electron beam distribution in the irradiation zone was measured using CTA and PVC foil dosimeters for available electron energy range. The temperature rise of the irradiated electric wire and irradiation homogeneity were evaluated for different experimental conditions to optimize technological process parameters. The results of computer simulation are consistent with the experimental data of dose distribution evaluated by gel-fraction measurements. Such conformity indicates that ModeCEB computer simulation is reliable and sufficient for optimization absorbed dose distribution in the multi-layer circular objects irradiated with scanned electron beams. - Highlights: ► We model wire and cables irradiation process by Monte Carlo simulations. ► We optimize irradiation configuration for various process parameters. ► Temperature rise and irradiation homogeneity were evaluated. ► Calculation (dose) and experimental (gel-fraction) results were compared. ► Computer simulation was found reliable and sufficient for process optimization.

  2. Verification of the behavior of insulating materials under ionizing radiation

    International Nuclear Information System (INIS)

    Reis, Joao C. Marques dos; Rezende, Aurimar de P.; Menzel, Silvio C.

    2009-01-01

    To analyze the behavior of specifics electrical insulating materials and components under ionizing radiation, a test program was developed to verify the overall effects of general electrical equipment under high radiation fields conditions. The main objective is for maintenance purposes, in the substitution of electrical components installed in the reactor building of the Angra 1 nuclear power plant. Knowing the characteristics of electrical insulating materials available in the country and determining by tests their ability to withstand the ionizing radiation effects, is feasible to implement specific maintenance services of electrical equipment, maintaining the same level of quality and safety for the specified application. This procedure reduces the time and also costs of maintenance services, in comparison with materials acquired or services performed abroad. The isolating materials and components of electrical equipment should be specified, manufactured and qualified to withstand aggressive environmental conditions in the reactor building during the normal operation and postulated accident. Additional tests should be conducted to verify the conditions of the aged material by ionizing radiation. Examples of additional tests: dielectric strength, tensile strength and elongation and impact resistance. (author)

  3. Metal-oxide assisted surface treatment of polyimide gate insulators for high-performance organic thin-film transistors.

    Science.gov (United States)

    Kim, Sohee; Ha, Taewook; Yoo, Sungmi; Ka, Jae-Won; Kim, Jinsoo; Won, Jong Chan; Choi, Dong Hoon; Jang, Kwang-Suk; Kim, Yun Ho

    2017-06-14

    We developed a facile method for treating polyimide-based organic gate insulator (OGI) surfaces with self-assembled monolayers (SAMs) by introducing metal-oxide interlayers, called the metal-oxide assisted SAM treatment (MAST). To create sites for surface modification with SAM materials on polyimide-based OGI (KPI) surfaces, the metal-oxide interlayer, here amorphous alumina (α-Al 2 O 3 ), was deposited on the KPI gate insulator using spin-coating via a rapid sol-gel reaction, providing an excellent template for the formation of a high-quality SAM with phosphonic acid anchor groups. The SAM of octadecylphosphonic acid (ODPA) was successfully treated by spin-coating onto the α-Al 2 O 3 -deposited KPI film. After the surface treatment by ODPA/α-Al 2 O 3 , the surface energy of the KPI thin film was remarkably decreased and the molecular compatibility of the film with an organic semiconductor (OSC), 2-decyl-7-phenyl-[1]benzothieno[3,2-b][1]benzothiophene (Ph-BTBT-C 10 ), was increased. Ph-BTBT-C 10 molecules were uniformly deposited on the treated gate insulator surface and grown with high crystallinity, as confirmed by atomic force microscopy (AFM) and X-ray diffraction (XRD) analysis. The mobility of Ph-BTBT-C 10 thin-film transistors (TFTs) was approximately doubled, from 0.56 ± 0.05 cm 2 V -1 s -1 to 1.26 ± 0.06 cm 2 V -1 s -1 , after the surface treatment. The surface treatment of α-Al 2 O 3 and ODPA significantly decreased the threshold voltage from -21.2 V to -8.3 V by reducing the trap sites in the OGI and improving the interfacial properties with the OSC. We suggest that the MAST method for OGIs can be applied to various OGI materials lacking reactive sites using SAMs. It may provide a new platform for the surface treatment of OGIs, similar to that of conventional SiO 2 gate insulators.

  4. Magnetic and electrical response of Co-doped La{sub 0.7}Ca{sub 0.3}MnO{sub 3} manganites/insulator system

    Energy Technology Data Exchange (ETDEWEB)

    Debnath, J.C., E-mail: Jyotish.debnath@deakin.edu.au [Institute for Frontier Materials, Deakin University, Geelong, VIC 3216 (Australia); Wang, Jianli, E-mail: jcd341@uowmail.edu.au [Institute for Superconductivity and Electronic Materials, University of Wollongong, Wollongong, NSW 2522 (Australia)

    2017-01-01

    We present a systematic study of the structural, magnetic and electrical properties of La{sub 0.7}Ca{sub 0.3}MnO{sub 3} (LCMO) and La{sub 0.7}Ca{sub 0.3}Mn{sub 0.95}Co{sub 0.05}O{sub 3} (LCMCO0 perovskite manganites. Most of the work is devoted to the electrical properties with a thorough discussion about different models for both the metallic and insulator states. With a view to understand the conduction mechanism in these materials, the resistivity of both materials was measured over a temperature range 5–300 K and in a magnetic field up to 1 T and the data were analysed by using several theoretical models. It has been observed that the metallic part of the temperature dependent resistivity (ρ) curve fits well with ρ=ρ{sub 0} +ρ{sub 2,5}Τ{sup 2,5}, indicating the electron–magnon scattering processes in the conduction of these materials. On the other hand, in the high temperature paramagnetic insulating regime, the adiabatic small polaron and VRH models fit well, thereby indicating that polaron hopping might be responsible for the conduction mechanism.

  5. Superconductivity induced by extremely high pressures in organic Mott-insulator β'-(BEDT-TTF)2IBrCl

    International Nuclear Information System (INIS)

    Kano, M; Uchiyama, K; Taniguchi, H; Hedo, M; Matsubayashi, K; Uwatoko, Y

    2009-01-01

    Previous research revealed that, at a pressure of 8.2 GPa, β'-(BEDT-TTF)2ICl2 possesses the highest transition temperature (T C ) among the organic conductors[1]. In the present work, transport studies under extremely high pressure of up to 10.0 GPa, using a cubic anvil press are reported for a related material, β'-(BEDT-TTF)2IBrCl which is an organic Mott-insulator in ambient pressure. Superconductivity with the highest T c (8.5 K, onset) was observed at P = 8.6 GPa.

  6. Influence of magneto-electric coefficient for magnetic and electric charge injection properties in magneto-electric MIS capacitors

    Energy Technology Data Exchange (ETDEWEB)

    Yokota, T; Tsuboi, Y; Imura, R; Kito, S; Gomi, M, E-mail: yokota.takeshi@nitech.ac.jp [Department of Material Science and Engineering, Graduate School of Nagoya Institute of Technology, Gokiso-cho, Showa-ku, Nagoya City, Aichi, 466-8555 (Japan)

    2011-10-29

    We investigated the electric charge injection properties of a floating-gate type metal-insulator Si capacitor having different-ME gate insulators. The samples showed charge-injection type behaviour in capacitance-voltage curves, and it was revealed that the amount of injected charges can be controlled by the application of an external magnetic field. The sample having a high-ME-coefficient gate insulator showed stepwise capacitance-voltage curves unlike the normal one. These results indicate that this capacitor, which employs a magnetic gate insulator, has the potential to be used in multilevel memory by the application of an external magnetic field.

  7. Influence of void defects on partial discharge behavior of superconducting busbar insulation

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Chunyu; Huang, Xiongyi, E-mail: huangxy@ipp.ac.cn; Lu, Kun; Li, Guoliang; Zhu, Haisheng; Wang, Jun; Wang, Cao; Dai, Zhiheng; Fang, Linlin; Song, Yuntao

    2017-06-15

    Highlights: • PD detection method was used to check the quality of the superconducting busbar insulation. • The samples with different void fraction were manufactured for comparing. • The discharge inception voltage, PRPD pattern was tested and studied for the samples with different void content. • The PD behaviors in oil bath and air condition were compared. - Abstract: For a magnetic confinement fusion device, the superconducting magnets and busbars need to be insulated with one layer of solid insulation to isolate the high voltage potential from the ground. The insulation layer commonly consists of several interleaved layers of epoxy resin-impregnated glass fiber tapes and polyimide films. The traditional electrical inspection methods for such solidified insulation on the magnet and busbar are a DC voltage test or a Paschen test. These tests measure the quality of the insulation based on the value of leakage currents. However, even if there is a larger quantity of high dielectric strength material implemented, if there are some microcavities or delaminations in the insulation system, the leakage current may be limited to microampere levels under testing levels over dozens of kilovolts. Therefore, it is difficult to judge the insulation quality just by the magnitudes of leakage current. Under long-term operation, such imperceptible defects will worsen and finally completely break down the insulation because of partial discharge (PD) incidents. Therefore, a PD detection test is an important complement to the DC voltage and Paschen tests for magnet and busbar insulations in the field of fusion. It is known that the PD detection test is a mature technique in the electric power industry. In this paper, the PD characteristics of samples containing glass fiber-reinforced composite insulations for use with the superconducting busbar were presented and discussed. Various samples with different void contents were prepared and the PD behaviors were tested.

  8. Influence of void defects on partial discharge behavior of superconducting busbar insulation

    International Nuclear Information System (INIS)

    Wang, Chunyu; Huang, Xiongyi; Lu, Kun; Li, Guoliang; Zhu, Haisheng; Wang, Jun; Wang, Cao; Dai, Zhiheng; Fang, Linlin; Song, Yuntao

    2017-01-01

    Highlights: • PD detection method was used to check the quality of the superconducting busbar insulation. • The samples with different void fraction were manufactured for comparing. • The discharge inception voltage, PRPD pattern was tested and studied for the samples with different void content. • The PD behaviors in oil bath and air condition were compared. - Abstract: For a magnetic confinement fusion device, the superconducting magnets and busbars need to be insulated with one layer of solid insulation to isolate the high voltage potential from the ground. The insulation layer commonly consists of several interleaved layers of epoxy resin-impregnated glass fiber tapes and polyimide films. The traditional electrical inspection methods for such solidified insulation on the magnet and busbar are a DC voltage test or a Paschen test. These tests measure the quality of the insulation based on the value of leakage currents. However, even if there is a larger quantity of high dielectric strength material implemented, if there are some microcavities or delaminations in the insulation system, the leakage current may be limited to microampere levels under testing levels over dozens of kilovolts. Therefore, it is difficult to judge the insulation quality just by the magnitudes of leakage current. Under long-term operation, such imperceptible defects will worsen and finally completely break down the insulation because of partial discharge (PD) incidents. Therefore, a PD detection test is an important complement to the DC voltage and Paschen tests for magnet and busbar insulations in the field of fusion. It is known that the PD detection test is a mature technique in the electric power industry. In this paper, the PD characteristics of samples containing glass fiber-reinforced composite insulations for use with the superconducting busbar were presented and discussed. Various samples with different void contents were prepared and the PD behaviors were tested.

  9. Magnetically insulated transmission line oscillator

    Science.gov (United States)

    Bacon, L.D.; Ballard, W.P.; Clark, M.C.; Marder, B.M.

    1987-05-19

    A magnetically insulated transmission line oscillator employs self-generated magnetic fields to generate microwave energy. An anode of the oscillator includes slow-wave structures which are formed of a plurality of thin conductive vanes defining cavities therebetween, and a gap is formed between the anode and a cathode of the oscillator. In response to a pulsed voltage applied to the anode and cathode, self-generated magnetic fields are produced in a cross-field orientation with respect to the orientation of the electric field between the anode and the cathode. The cross-field magnetic fields insulate the flow of electrons in the gap and confine the flow of electrons within the gap. 11 figs.

  10. Radiation processing of polymer insulators as a method of improving their properties and performance

    International Nuclear Information System (INIS)

    Ivanov, V.S.; Migunova, L.I.; Kalinina, N.A.; Aleksandrov, G.N.

    1995-01-01

    Polymer insulators for electric apparatus and high-voltage overhead lines are promising for replacing porcelain and glass insulators. The possibility of application of radiation-chemical technology was showed by manufacture of rod-shaped polymer insulators. In this work, an ethylene and vinyl acetate copolymer was used as the polymer basis of the composition for insulators. By forming a three-dimensional network in polymer bulk radiation processing improves service properties of polymer insulators: shape and heat stability > 200 degree C and stability to tracking erosion > 200 h

  11. New Developments in the Field of Materials for Electric Power Engineering. Paper presented at the ETG Conference (Energy Technology Society) 1981

    Energy Technology Data Exchange (ETDEWEB)

    1981-01-01

    The Conference Proceedings comprise 21 papers divided into 4 theme groups: insulating materials and insulating systems; structural materials; magnetic materials; conductor and contact materials. Individual papers deal with: the search for a new insulating system for transformers; insulating oils and liquids; an insulating system for electric machines of high heat resistance: progress in insulation of exciter winding in hydroelectic generators and other large synchronous machines; insulating systems for extreme envronmental conditions; behavior of silicon elastomer, organic, and polyethylene insulating materials; development of new magnetic materials, in particular: metallic glasses; amorphous magnetic materials; pressed iron powder parts; modern permanent magnetic materials; development of new contact materials for power switchgear; alternative switchgear technologies; a new cryogenic conductor structured element based on V/sub 2/O/sub 3/ ceramic; choice of material for fuses.

  12. Superconductivity and ferromagnetism in topological insulators

    Science.gov (United States)

    Zhang, Duming

    Topological insulators, a new state of matter discovered recently, have attracted great interest due to their novel properties. They are insulating inside the bulk, but conducting at the surface or edges. This peculiar behavior is characterized by an insulating bulk energy gap and gapless surface or edge states, which originate from strong spin-orbit coupling and time-reversal symmetry. The spin and momentum locked surface states not only provide a model system to study fundamental physics, but can also lead to applications in spintronics and dissipationless electronics. While topological insulators are interesting by themselves, more exotic behaviors are predicted when an energy gap is induced at the surface. This dissertation explores two types of surface state gap in topological insulators, a superconducting gap induced by proximity effect and a magnetic gap induced by chemical doping. The first three chapters provide introductory theory and experimental details of my research. Chapter 1 provides a brief introduction to the theoretical background of topological insulators. Chapter 2 is dedicated to material synthesis principles and techniques. I will focus on two major synthesis methods: molecular beam epitaxy for the growth of Bi2Se3 thin films and chemical vapor deposition for the growth of Bi2Se3 nanoribbons and nanowires. Material characterization is discussed in Chapter 3. I will describe structural, morphological, magnetic, electrical, and electronic characterization techniques used to study topological insulators. Chapter 4 discusses the experiments on proximity-induced superconductivity in topological insulator (Bi2Se3) nanoribbons. This work is motivated by the search for the elusive Majorana fermions, which act as their own antiparticles. They were proposed by Ettore Majorara in 1937, but have remained undiscovered. Recently, Majorana's concept has been revived in condensed matter physics: a condensed matter analog of Majorana fermions is predicted to

  13. Harnessing the metal-insulator transition for tunable metamaterials

    Science.gov (United States)

    Charipar, Nicholas A.; Charipar, Kristin M.; Kim, Heungsoo; Bingham, Nicholas S.; Suess, Ryan J.; Mathews, Scott A.; Auyeung, Raymond C. Y.; Piqué, Alberto

    2017-08-01

    The control of light-matter interaction through the use of subwavelength structures known as metamaterials has facilitated the ability to control electromagnetic radiation in ways not previously achievable. A plethora of passive metamaterials as well as examples of active or tunable metamaterials have been realized in recent years. However, the development of tunable metamaterials is still met with challenges due to lack of materials choices. To this end, materials that exhibit a metal-insulator transition are being explored as the active element for future metamaterials because of their characteristic abrupt change in electrical conductivity across their phase transition. The fast switching times (▵t < 100 fs) and a change in resistivity of four orders or more make vanadium dioxide (VO2) an ideal candidate for active metamaterials. It is known that the properties associated with thin film metal-insulator transition materials are strongly dependent on the growth conditions. For this work, we have studied how growth conditions (such as gas partial pressure) influence the metalinsulator transition in VO2 thin films made by pulsed laser deposition. In addition, strain engineering during the growth process has been investigated as a method to tune the metal-insulator transition temperature. Examples of both the optical and electrical transient dynamics facilitating the metal-insulator transition will be presented together with specific examples of thin film metamaterial devices.

  14. Chern structure in the Bose-insulating phase of Sr2RuO4 nanofilms

    Science.gov (United States)

    Nobukane, Hiroyoshi; Matsuyama, Toyoki; Tanda, Satoshi

    2017-01-01

    The quantum anomaly that breaks the symmetry, for example the parity and the chirality, in the quantization leads to a physical quantity with a topological Chern invariant. We report the observation of a Chern structure in the Bose-insulating phase of Sr2RuO4 nanofilms by employing electric transport. We observed the superconductor-to-insulator transition by reducing the thickness of Sr2RuO4 single crystals. The appearance of a gap structure in the insulating phase implies local superconductivity. Fractional quantized conductance was observed without an external magnetic field. We found an anomalous induced voltage with temperature and thickness dependence, and the induced voltage exhibited switching behavior when we applied a magnetic field. We suggest that there was fractional magnetic-field-induced electric polarization in the interlayer. These anomalous results are related to topological invariance. The fractional axion angle Θ = π/6 was determined by observing the topological magneto-electric effect in the Bose-insulating phase of Sr2RuO4 nanofilms.

  15. Flame spread over inclined electrical wires with AC electric fields

    KAUST Repository

    Lim, Seung J.; Park, Sun H.; Park, Jeong; Fujita, Osamu; Keel, Sang I.; Chung, Suk-Ho

    2017-01-01

    Flame spread over polyethylene-insulated electrical wires was studied experimentally with applied alternating current (AC) by varying the inclination angle (θ), applied voltage (VAC), and frequency (fAC). For the baseline case with no electric field

  16. A silicon-on-insulator vertical nanogap device for electrical transport measurements in aqueous electrolyte solution

    Energy Technology Data Exchange (ETDEWEB)

    Strobel, Sebastian [Walter Schottky Institut, Technische Universitaet Muenchen, Am Coulombwall, D-85748 Garching (Germany); Arinaga, Kenji [Walter Schottky Institut, Technische Universitaet Muenchen, Am Coulombwall, D-85748 Garching (Germany); Hansen, Allan [Walter Schottky Institut, Technische Universitaet Muenchen, Am Coulombwall, D-85748 Garching (Germany); Tornow, Marc [Walter Schottky Institut, Technische Universitaet Muenchen, Am Coulombwall, D-85748 Garching (Germany)

    2007-07-25

    A novel concept for metal electrodes with few 10 nm separation for electrical conductance measurements in an aqueous electrolyte environment is presented. Silicon-on-insulator (SOI) material with 10 nm buried silicon dioxide serves as a base substrate for the formation of SOI plateau structures which, after recess-etching the thin oxide layer, thermal oxidation and subsequent metal thin film evaporation, feature vertically oriented nanogap electrodes at their exposed sidewalls. During fabrication only standard silicon process technology without any high-resolution nanolithographic techniques is employed. The vertical concept allows an array-like parallel processing of many individual devices on the same substrate chip. As analysed by cross-sectional TEM analysis the devices exhibit a well-defined material layer architecture, determined by the chosen material thicknesses and process parameters. To investigate the device in aqueous solution, we passivated the sample surface by a polymer layer, leaving a micrometre-size fluid access window to the nanogap region only. First current-voltage characteristics of a 65 nm gap device measured in 60 mM buffer solution reveal excellent electrical isolation behaviour which suggests applications in the field of biomolecular electronics in a natural environment.

  17. High Temperature Electrical Insulation Materials for Space Applications, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — NASA's future space science missions cannot be realized without the state of the art high temperature insulation materials of which higher working temperature, high...

  18. Performance investigation of heat insulation solar glass for low-carbon buildings

    International Nuclear Information System (INIS)

    Cuce, Erdem; Young, Chin-Huai; Riffat, Saffa B.

    2014-01-01

    Highlights: • U-value of HISG is found to be 1.10 W/m 2 K. • Maximum temperature difference is achieved by HISG with 12.70 °C. • HISG provides two times better insulation than standard double glazed windows. • HISG generates over 40 W electricity from a glazing surface of 0.66 m 2 . • 100% of UV in incoming solar radiation is absorbed by HISG. - Abstract: Heat insulation solar glass (HISG), which has been recently developed by Professor Chin-Huai Young in Taiwan is an extraordinary glazing technology for low/zero carbon buildings. HISG differs from traditional glazing technologies with its ability of producing electricity. It also offers some additional features such as thermal insulation, sound insulation, self-cleaning and energy saving. In this work, thermal insulation, power generation and optical performance of HISG are experimentally investigated. Thermal insulation performance of HISG is analysed through standardized co-heating test methodology, and the results are compared with different traditional double glazed window samples. For the power generation and optical performance of HISG, two samples (air filled HISG and Argon filled HISG) are experimentally investigated in real and simulated operating conditions. The results indicate that both configurations show similar performance in terms of power generation. Under a solar intensity of 850 W/m 2 , over 40 W electrical power is achieved from HISG samples with a glazing area of 0.66 m 2 . Performance of samples under solar simulator is not found to be promising due to the absence of UV and IR parts in the artificial light source. In terms of thermal insulation ability, HISG is also found to be attractive. The average U-value of HISG is determined to be 1.10 W/m 2 K, which is two times better than standard double glazed windows. Some simulation results for two different cities (Taipei, Taiwan and Nottingham, UK) demonstrating the energy saving potential of HISG are also presented

  19. Review of Physicochemical-Based Diagnostic Techniques for Assessing Insulation Condition in Aged Transformers

    Directory of Open Access Journals (Sweden)

    Janvier Sylvestre N’cho

    2016-05-01

    Full Text Available A power transformer outage has a dramatic financial consequence not only for electric power systems utilities but also for interconnected customers. The service reliability of this important asset largely depends upon the condition of the oil-paper insulation. Therefore, by keeping the qualities of oil-paper insulation system in pristine condition, the maintenance planners can reduce the decline rate of internal faults. Accurate diagnostic methods for analyzing the condition of transformers are therefore essential. Currently, there are various electrical and physicochemical diagnostic techniques available for insulation condition monitoring of power transformers. This paper is aimed at the description, analysis and interpretation of modern physicochemical diagnostics techniques for assessing insulation condition in aged transformers. Since fields and laboratory experiences have shown that transformer oil contains about 70% of diagnostic information, the physicochemical analyses of oil samples can therefore be extremely useful in monitoring the condition of power transformers.

  20. A quantized microwave quadrupole insulator with topologically protected corner states

    Science.gov (United States)

    Peterson, Christopher W.; Benalcazar, Wladimir A.; Hughes, Taylor L.; Bahl, Gaurav

    2018-03-01

    The theory of electric polarization in crystals defines the dipole moment of an insulator in terms of a Berry phase (geometric phase) associated with its electronic ground state. This concept not only solves the long-standing puzzle of how to calculate dipole moments in crystals, but also explains topological band structures in insulators and superconductors, including the quantum anomalous Hall insulator and the quantum spin Hall insulator, as well as quantized adiabatic pumping processes. A recent theoretical study has extended the Berry phase framework to also account for higher electric multipole moments, revealing the existence of higher-order topological phases that have not previously been observed. Here we demonstrate experimentally a member of this predicted class of materials—a quantized quadrupole topological insulator—produced using a gigahertz-frequency reconfigurable microwave circuit. We confirm the non-trivial topological phase using spectroscopic measurements and by identifying corner states that result from the bulk topology. In addition, we test the critical prediction that these corner states are protected by the topology of the bulk, and are not due to surface artefacts, by deforming the edges of the crystal lattice from the topological to the trivial regime. Our results provide conclusive evidence of a unique form of robustness against disorder and deformation, which is characteristic of higher-order topological insulators.

  1. 77 FR 39858 - Revisions to Electric Reliability Organization Definition of Bulk Electric System and Rules of...

    Science.gov (United States)

    2012-07-05

    ... bulk electric system reliability through steady state power flow, and contain a transient stability... Commission 18 CFR Part 40 Revisions to Electric Reliability Organization Definition of Bulk Electric System... definition of ``bulk electric system'' developed by the North American Electric Reliability Corporation (NERC...

  2. Design and analysis of the PBFA-Z vacuum insulator stack

    International Nuclear Information System (INIS)

    Shoup, R.W.; Long, F.; Martin, T.H.; Stygar, W.A.; Spielman, R.B.; Struve, K.W.; Mostrom, M.; Corcoran, P.; Smith, I.

    1996-01-01

    Sandia is developing PBFA-Z, a 20-MA driver for z-pinch experiments by replacing the water lines, insulator stack, and MITLs on PBFA II with new hardware. The design of the vacuum insulator stack was dictated by the drive voltage, the electric field stress and grading requirements, the water line and MITL interface requirements, and the machine operations and maintenance requirements. The insulator stack will consist of four separate modules, each of a different design because of different voltage drive and hardware interface requirements. The shape of the components in each module, i.e., grading rings, insulator rings, flux excluders, anode and cathode conductors, and the design of the water line and MITL interfaces, were optimized by using the electrostatic analysis codes, ELECTRO and JASON. The time-dependent performance of the insulator stack was evaluated using IVORY, a 2-D PIC code. The insulator stack design and present the results of the ELECTRO and IVORY analyses are described. (author). 2 tabs., 9 figs., 3 refs

  3. Design and analysis of the PBFA-Z vacuum insulator stack

    Energy Technology Data Exchange (ETDEWEB)

    Shoup, R W [Field Command Defense Nuclear Agency, Kirtland AFB, NM (United States); Long, F; Martin, T H; Stygar, W A; Spielman, R B [Sandia National Laboratories, Albuquerque, NM (United States). Dept 9573; Ives, H [EG and G, Albuquerque, NM (United States); Struve, K W; Mostrom, M [Mission Research Corp., Albuquerque, NM (United States); Corcoran, P; Smith, I [Pulse Sciences, Inc., San Leandro, CA (United States)

    1997-12-31

    Sandia is developing PBFA-Z, a 20-MA driver for z-pinch experiments by replacing the water lines, insulator stack, and MITLs on PBFA II with new hardware. The design of the vacuum insulator stack was dictated by the drive voltage, the electric field stress and grading requirements, the water line and MITL interface requirements, and the machine operations and maintenance requirements. The insulator stack will consist of four separate modules, each of a different design because of different voltage drive and hardware interface requirements. The shape of the components in each module, i.e., grading rings, insulator rings, flux excluders, anode and cathode conductors, and the design of the water line and MITL interfaces, were optimized by using the electrostatic analysis codes, ELECTRO and JASON. The time-dependent performance of the insulator stack was evaluated using IVORY, a 2-D PIC code. The insulator stack design and present the results of the ELECTRO and IVORY analyses are described. (author). 2 tabs., 9 figs., 3 refs.

  4. HgTe based topological insulators

    International Nuclear Information System (INIS)

    Bruene, Christoph

    2014-01-01

    This PhD thesis summarizes the discovery of topological insulators and highlights the developments on their experimental observations. The work focuses on HgTe. The thesis is structured as follows: - The first chapter of this thesis will give a brief overview on discoveries in the field of topological insulators. It focuses on works relevant to experimental results presented in the following chapters. This includes a short outline of the early predictions and a summary of important results concerning 2-dimensional topological insulators while the final section discusses observations concerning 3-dimensional topological insulators. - The discovery of the quantum spin Hall effect in HgTe marked the first experimental observation of a topological insulator. Chapter 2 focuses on HgTe quantum wells and the quantum spin Hall effect. The growth of high quality HgTe quantum wells was one of the major goals for this work. In a final set of experiments the spin polarization of the edge channels was investigated. Here, we could make use of the advantage that HgTe quantum well structures exhibit a large Rashba spin orbit splitting. - HgTe as a 3-dimensional topological insulator is presented in chapter 3. - Chapters 4-6 serve as in depth overviews of selected works: Chapter 4 presents a detailed overview on the all electrical detection of the spin Hall effect in HgTe quantum wells. The detection of the spin polarization of the quantum spin Hall effect is shown in chapter 5 and chapter 6 gives a detailed overview on the quantum Hall effect originating from the topological surface state in strained bulk HgTe.

  5. Polymer Coating of Carbon Nanotube Fibers for Electric Microcables

    Directory of Open Access Journals (Sweden)

    Noe T. Alvarez

    2014-11-01

    Full Text Available Carbon nanotubes (CNTs are considered the most promising candidates to replace Cu and Al in a large number of electrical, mechanical and thermal applications. Although most CNT industrial applications require macro and micro size CNT fiber assemblies, several techniques to make conducting CNT fibers, threads, yarns and ropes have been reported to this day, and improvement of their electrical and mechanical conductivity continues. Some electrical applications of these CNT conducting fibers require an insulating layer for electrical insulation and protection against mechanical tearing. Ideally, a flexible insulator such as hydrogenated nitrile butadiene rubber (HNBR on the CNT fiber can allow fabrication of CNT coils that can be assembled into lightweight, corrosion resistant electrical motors and transformers. HNBR is a largely used commercial polymer that unlike other cable-coating polymers such as polyvinyl chloride (PVC, it provides unique continuous and uniform coating on the CNT fibers. The polymer coated/insulated CNT fibers have a 26.54 μm average diameter—which is approximately four times the diameter of a red blood cell—is produced by a simple dip-coating process. Our results confirm that HNBR in solution creates a few microns uniform insulation and mechanical protection over a CNT fiber that is used as the electrically conducting core.

  6. Polymer Coating of Carbon Nanotube Fibers for Electric Microcables

    Science.gov (United States)

    Alvarez, Noe T.; Ochmann, Timothy; Kienzle, Nicholas; Ruff, Brad; Haase, Mark R.; Hopkins, Tracy; Pixley, Sarah; Mast, David; Schulz, Mark J.; Shanov, Vesselin

    2014-01-01

    Carbon nanotubes (CNTs) are considered the most promising candidates to replace Cu and Al in a large number of electrical, mechanical and thermal applications. Although most CNT industrial applications require macro and micro size CNT fiber assemblies, several techniques to make conducting CNT fibers, threads, yarns and ropes have been reported to this day, and improvement of their electrical and mechanical conductivity continues. Some electrical applications of these CNT conducting fibers require an insulating layer for electrical insulation and protection against mechanical tearing. Ideally, a flexible insulator such as hydrogenated nitrile butadiene rubber (HNBR) on the CNT fiber can allow fabrication of CNT coils that can be assembled into lightweight, corrosion resistant electrical motors and transformers. HNBR is a largely used commercial polymer that unlike other cable-coating polymers such as polyvinyl chloride (PVC), it provides unique continuous and uniform coating on the CNT fibers. The polymer coated/insulated CNT fibers have a 26.54 μm average diameter—which is approximately four times the diameter of a red blood cell—is produced by a simple dip-coating process. Our results confirm that HNBR in solution creates a few microns uniform insulation and mechanical protection over a CNT fiber that is used as the electrically conducting core. PMID:28344254

  7. Management plan for electrical insulation, transformers and bulbs high pressure sodium retired from electrical distribution lines of the Unidad Estrategica de Negocios Servicio al Cliente Electricidad of the Instituto Costarricense de Electricidad

    International Nuclear Information System (INIS)

    Badilla Sanabria, Daniela; Chaves Morales, Angelica; Rodriguez Mendez, Susan

    2012-01-01

    The Unidad Estrategica de Negocios Servicio al Cliente Electricidad of Instituto Costarricense de Electricidad has completed a management plan for electrical insulation, transformers and sodium vapor bulbs high pressure, that are retired from electrical distribution lines. The three residues have been characterized and identified in its physical composition, chemical and hazardous properties, generating selection, analysis and proposals for alternative of recovery, treatment or final disposal, viable from an environmental, technical and economic view. A series of recommendations and procedures have been performed using tabs and instructions for the purpose of unifying management practices appropriate in the Area de Sostenibilidad Ambiental of the ICE. (author) [es

  8. Novel Synchronous Linear and Rotatory Micro Motors Based on Polymer Magnets with Organic and Inorganic Insulation Layers

    Directory of Open Access Journals (Sweden)

    Andreas WALDSCHIK

    2008-12-01

    Full Text Available In this work, we report on the development of several synchronous motors with rotatory or linear movements. The synchronous micro motors are brushless DC motors or stepper motors with electrically controlled commutation consisting of a stator and a rotor. The rotor is mounted onto the stator and is adjusted by an integrated guidance. Inside the stator different coil systems are realized, like double layer sector coils or special nested coils. The coil systems can be controlled by three or six phases depending on the operational mode. Furthermore, inorganic insulation layers were used in order to reduce the thickness of the system. By this means four layers of electrical conductors can be realized especially for the 2D devices. The smallest diameter of the rotatory motor is 1 mm and could be successfully driven.

  9. Standard Test Methods for Insulation Integrity and Ground Path Continuity of Photovoltaic Modules

    CERN Document Server

    American Society for Testing and Materials. Philadelphia

    2000-01-01

    1.1 These test methods cover procedures for (1) testing for current leakage between the electrical circuit of a photovoltaic module and its external components while a user-specified voltage is applied and (2) for testing for possible module insulation breakdown (dielectric voltage withstand test). 1.2 A procedure is described for measuring the insulation resistance between the electrical circuit of a photovoltaic module and its external components (insulation resistance test). 1.3 A procedure is provided for verifying that electrical continuity exists between the exposed external conductive surfaces of the module, such as the frame, structural members, or edge closures, and its grounding point (ground path continuity test). 1.4 This test method does not establish pass or fail levels. The determination of acceptable or unacceptable results is beyond the scope of this test method. 1.5 There is no similar or equivalent ISO standard. This standard does not purport to address all of the safety concerns, if a...

  10. The pursuit of electrically-driven organic semiconductor lasers

    NARCIS (Netherlands)

    Bisri, Satria Zulkarnaen; Takenobu, Taishi; Iwasa, Yoshihiro

    2014-01-01

    Organic semiconductors have many favourable and plastic-like optical properties that are promising for the development of low energy consuming laser devices. Although optically-pumped organic semiconductor lasers have been demonstrated since the early days of lasers, electrically-driven organic

  11. Tetradymites as thermoelectrics and topological insulators

    Science.gov (United States)

    Heremans, Joseph P.; Cava, Robert J.; Samarth, Nitin

    2017-10-01

    Tetradymites are M2X3 compounds — in which M is a group V metal, usually Bi or Sb, and X is a group VI anion, Te, Se or S — that crystallize in a rhombohedral structure. Bi2Se3, Bi2Te3 and Sb2Te3 are archetypical tetradymites. Other mixtures of M and X elements produce common variants, such as Bi2Te2Se. Because tetradymites are based on heavy p-block elements, strong spin-orbit coupling greatly influences their electronic properties, both on the surface and in the bulk. Their surface electronic states are a cornerstone of frontier work on topological insulators. The bulk energy bands are characterized by small energy gaps, high group velocities, small effective masses and band inversion near the centre of the Brillouin zone. These properties are favourable for high-efficiency thermoelectric materials but make it difficult to obtain an electrically insulating bulk, which is a requirement of topological insulators. This Review outlines recent progress made in bulk and thin-film tetradymite materials for the optimization of their properties both as thermoelectrics and as topological insulators.

  12. Electric Power Transmission Lines

    Data.gov (United States)

    Department of Homeland Security — Transmission Lines are the system of structures, wires, insulators and associated hardware that carry electric energy from one point to another in an electric power...

  13. Insulation coordination workstation for AC and DC substations

    International Nuclear Information System (INIS)

    Booth, R.R.; Hileman, A.R.

    1990-01-01

    The Insulation Coordination Workstation was designed to aid the substation design engineer in the insulation coordination process. The workstation utilizes state of the art computer technology to present a set of tools necessary for substation insulation coordination, and to support the decision making process for all aspects of insulation coordination. The workstation is currently being developed for personal computers supporting OS/2 Presentation Manager. Modern Computer-Aided Software Engineering (CASE) technology was utilized to create an easily expandable framework which currently consists of four modules, each accessing a central application database. The heart of the workstation is a library of user-friendly application programs for the calculation of important voltage stresses used for the evaluation of insulation coordination. The Oneline Diagram is a graphic interface for data entry into the EPRI distributed EMTP program, which allows the creation of complex systems on the CRT screen using simple mouse clicks and keyboard entries. Station shielding is graphically represented in the Geographic Viewport using a three-dimensional substation model, and the interactive plotting package allows plotting of EPRI EMTP output results on the CRT screen, printer, or pen plotter. The Insulation Coordination Workstation was designed by Advanced Systems Technology (AST), a division of ABB Power Systems, Inc., and sponsored by the Electric Power Research Institute under RP 2323-5, AC/DC Insulation Coordination Workstation

  14. National Electric Sector Cybersecurity Organization Resource (NESCOR)

    Energy Technology Data Exchange (ETDEWEB)

    None, None

    2014-06-30

    The goal of the National Electric Sector Cybersecurity Organization Resource (NESCOR) project was to address cyber security issues for the electric sector, particularly in the near and mid-term. The following table identifies the strategies from the DOE Roadmap to Achieve Energy Delivery Systems Cybersecurity published in September 2011 that are applicable to the NESCOR project.

  15. Interfacial Coatings for Inorganic Composite Insulation Systems

    International Nuclear Information System (INIS)

    Hooker, M. W.; Fabian, P. E.; Stewart, M. W.; Grandlienard, S. D.; Kano, K. S.

    2006-01-01

    Inorganic (ceramic) insulation materials are known to have good radiation resistance and desirable electrical and mechanical properties at cryogenic and elevated temperatures. In addition, ceramic materials can withstand the high-temperature reaction cycle used with Nb3Sn superconductor materials, allowing the insulation to be co-processed with the superconductor in a wind-and-react fabrication process. A critical aspect in the manufacture of ceramic-based insulation systems is the deposition of suitable fiber-coating materials that prevent chemical reaction of the fiber and matrix materials, and thus provide a compliant interface between the fiber and matrix, which minimizes the impact of brittle failure of the ceramic matrix. Ceramic insulation produced with CTD-FI-202 fiber interfaces have been found to exhibit very high shear and compressive strengths. However, this material is costly to produce. Thus, the goal of the present work is to evaluate alternative, lower-cost materials and processes. A variety of oxide and polyimide coatings were evaluated, and one commercially available polyimide coating has been shown to provide some improvement as compared to uncoated and de-sized S2 glass

  16. Effect of AC electric fields on flame spread over electrical wire

    KAUST Repository

    Kim, Minkuk

    2011-01-01

    The effect of electric fields on the characteristics of flame spread over insulated electrical wire has been investigated experimentally by varying AC voltage and frequency applied to the wire in the normal gravity condition. The polyethylene (PE) insulated electrical wire was placed horizontally on electrically non-conducting posts and one end of the wire was connected to the high voltage terminal. Thus, the electrical system is the single electrode configuration. The wire was ignited at one end and the flame spread rate along the wire has been measured from the images using a video camera. Two distinct regimes existed depending on the applied AC frequency. In the low frequency regime, the flame spread rate decreased with the frequency and voltage. While in the high frequency regime, it decreased initially with voltage and then increased. At high frequency, the spread rate was even over that without applying electric fields. This result implies that fire safety codes developed without considering the effect of electric fields may require modifications. © 2010 Published by Elsevier Inc. on behalf of The Combustion Institute. All rights reserved.

  17. Air insulated cables for medium and low voltage supplies of the EVU

    Energy Technology Data Exchange (ETDEWEB)

    Dienstel, S

    1977-02-01

    Air insulated cables and insulated overhead cables are electrical components, which, by the use of new insulating materials and technology, are particularly suitable for the introduction of systems for overhead power transmission plants. They combine the favorable properties of underground cables, such as compact construction and low inductance, with their high mechanical strength. The present report deals with the construction, accessories and technical properties of these cables. The constructional and operational aspects of such systems and their costs are also discussed.

  18. Metal-insulator transition in tin doped indium oxide (ITO thin films: Quantum correction to the electrical conductivity

    Directory of Open Access Journals (Sweden)

    Deepak Kumar Kaushik

    2017-01-01

    Full Text Available Tin doped indium oxide (ITO thin films are being used extensively as transparent conductors in several applications. In the present communication, we report the electrical transport in DC magnetron sputtered ITO thin films (prepared at 300 K and subsequently annealed at 673 K in vacuum for 60 minutes in low temperatures (25-300 K. The low temperature Hall effect and resistivity measurements reveal that the ITO thin films are moderately dis-ordered (kFl∼1; kF is the Fermi wave vector and l is the electron mean free path and degenerate semiconductors. The transport of charge carriers (electrons in these disordered ITO thin films takes place via the de-localized states. The disorder effects lead to the well-known ‘metal-insulator transition’ (MIT which is observed at 110 K in these ITO thin films. The MIT in ITO thin films is explained by the quantum correction to the conductivity (QCC; this approach is based on the inclusion of quantum-mechanical interference effects in Boltzmann’s expression of the conductivity of the disordered systems. The insulating behaviour observed in ITO thin films below the MIT temperature is attributed to the combined effect of the weak localization and the electron-electron interactions.

  19. Metal-insulator transition in tin doped indium oxide (ITO) thin films: Quantum correction to the electrical conductivity

    Science.gov (United States)

    Kaushik, Deepak Kumar; Kumar, K. Uday; Subrahmanyam, A.

    2017-01-01

    Tin doped indium oxide (ITO) thin films are being used extensively as transparent conductors in several applications. In the present communication, we report the electrical transport in DC magnetron sputtered ITO thin films (prepared at 300 K and subsequently annealed at 673 K in vacuum for 60 minutes) in low temperatures (25-300 K). The low temperature Hall effect and resistivity measurements reveal that the ITO thin films are moderately dis-ordered (kFl˜1; kF is the Fermi wave vector and l is the electron mean free path) and degenerate semiconductors. The transport of charge carriers (electrons) in these disordered ITO thin films takes place via the de-localized states. The disorder effects lead to the well-known `metal-insulator transition' (MIT) which is observed at 110 K in these ITO thin films. The MIT in ITO thin films is explained by the quantum correction to the conductivity (QCC); this approach is based on the inclusion of quantum-mechanical interference effects in Boltzmann's expression of the conductivity of the disordered systems. The insulating behaviour observed in ITO thin films below the MIT temperature is attributed to the combined effect of the weak localization and the electron-electron interactions.

  20. Heat conduction coefficient and coefficient of linear thermal expansion of electric insulation materials for superconducting magnetic system

    International Nuclear Information System (INIS)

    Deev, V.I.; Sobolev, V.P.; Kruglov, A.B.; Pridantsev, A.I.

    1984-01-01

    Results of experimental investigation of heat conduction coefficient and coefficient of linear thermal expansion and thermal shrinkages of the STEF-1 textolite-glass widely used in superconducting magnetic systems as electric insulating and structural material are presented. Samples of two types have been died: sample axisa is perpendicular to a plae of fiberglass layers ad sample axis is parallel to a plane of fiberglass layers. Heat conduction coefficient was decreased almost a five times with temperature decrease from 300 up to 5K and was slightly dependent on a sample type. Temperature variation of linear dimensions in a sample of the first type occurs in twice as fast as compared to the sample of the second type

  1. Surface electrical resistivity of insulators

    International Nuclear Information System (INIS)

    Senn, B. C.; Liesegang, J.

    1996-01-01

    A method is presented here for measuring surface charge decay, and theory has been developed so as to produce determinations of resistivity in the surface region of insulator films or wafers. This method incorporates the use of a coaxial cylindrical capacitor arrangement and an electrometer interfaced to a PC. The charge transport theory given here is based on Mott-Gurney diffusion, and allows easy interpretation of the experimental data, especially for the initial phase of surface charge decay. Resistivity measurements are presented for glass, mica, perspex and polyethylene, covering a range of 10 9 to 10 18 Ωm, as an illustration of the useful range of the instrument for static and antistatic materials, particularly in film or sheet form. Values for the surface charge diffusion constants of the materials are also presented. The charge transport theory has also been extended to allow the experimental and computational theoretical comparison of surface charge decay not only over the initial phase of charge decay, but also over longer times. The theoretical predictions show excellent agreement with experiment using the values for the diffusion constants referred to above

  2. Electric organ discharge diversification in mormyrid weakly electric fish is associated with differential expression of voltage-gated ion channel genes.

    Science.gov (United States)

    Nagel, Rebecca; Kirschbaum, Frank; Tiedemann, Ralph

    2017-03-01

    In mormyrid weakly electric fish, the electric organ discharge (EOD) is used for species recognition, orientation and prey localization. Produced in the muscle-derived adult electric organ, the EOD exhibits a wide diversity across species in both waveform and duration. While certain defining EOD characteristics can be linked to anatomical features of the electric organ, many factors underlying EOD differentiation are yet unknown. Here, we report the differential expression of 13 Kv1 voltage-gated potassium channel genes, two inwardly rectifying potassium channel genes, two previously studied sodium channel genes and an ATPase pump in two sympatric species of the genus Campylomormyrus in both the adult electric organ and skeletal muscle. Campylomormyrus compressirostris displays a basal EOD, largely unchanged during development, while C. tshokwe has an elongated, putatively derived discharge. We report an upregulation in all Kv1 genes in the electric organ of Campylomormyrus tshokwe when compared to both skeletal muscle and C. compressirostris electric organ. This pattern of upregulation in a species with a derived EOD form suggests that voltage-gated potassium channels are potentially involved in the diversification of the EOD signal among mormyrid weakly electric fish.

  3. Fabrication of insulator nanocapillaries from diatoms

    International Nuclear Information System (INIS)

    Bereczky, R.J.; Tokesi, K.

    2006-01-01

    Complete text of publication follows. Diatoms are unicellular microscopic organisms with silicon-dioxide based skeleton enveloped with an organic material, which composes essentially polysaccharides and proteins (see Fig. 1a.). As it was shown, the valva of the diatoms build up almost from clean silicondioxide [1]. Therefore, removing the organic compounds from the diatom, we can have in our hand an ideal, about 100 μ m-sized, and almost cylindrical shaped insulating nanostructure. There are various techniques available to disembarrass the diatom from its organic compounds. We used the so called hydrogen peroxide method. The advantageous properties of this method are the followings: a) this is one of the fastest procedures among the possible methods, b) do not require special equipment, c) cheap, and last but not least it is less harmful for health compared to other methods. This procedure can be an alternative way of the fabrication of insulator nanocapillaries. In this case the preparation of the nanocapillaries is simple and quick. Moreover, we do not need to invest expensive special techniques, (like micromachining-, electrochemical etching technique, moulding process etc) as it was necessary for the case of previously developed method producing insulator nanocapillaries [2,3]. Fig. 1b and Fig. 1c. show the scanning electron micrograph of the skeleton of the diatoms. The size of the cylindrical holes are roughly 200 nm (see Fig. 1c). (author)

  4. Electrically floating, near vertical incidence, skywave antenna

    Science.gov (United States)

    Anderson, Allen A.; Kaser, Timothy G.; Tremblay, Paul A.; Mays, Belva L.

    2014-07-08

    An Electrically Floating, Near Vertical Incidence, Skywave (NVIS) Antenna comprising an antenna element, a floating ground element, and a grounding element. At least part of said floating ground element is positioned between said antenna element and said grounding element. The antenna is separated from the floating ground element and the grounding element by one or more electrical insulators. The floating ground element is separated from said antenna and said grounding element by one or more electrical insulators.

  5. Irradiation and testing of compact ignition tokamak toroidal field coil insulation materials

    International Nuclear Information System (INIS)

    Kanemoto, G.K.; Sherick, M.J.; Sparks, D.C.

    1990-05-01

    This report documents the results of an irradiation and testing program performed on behalf of Martin Marietta Energy Systems, Inc. in support of the Compact Ignition Tokamak Research and Development program. The purpose of the irradiation and testing program was to determine the effects of neutron and gamma irradiation on the mechanical and electrical properties of candidate toroidal field coil insulation materials. Insulation samples were irradiated in the Advanced Test Reactor (ATR) in a large I-hole. The insulation samples were irradiated within a lead shield to reduce exposure to gamma radiation to better approximate the desired ration of neutron to gamma exposure. Two different exposure levels were specified for the insulation samples. To accomplish this, the samples were encapsulated in two separate aluminum capsules; the capsules positioned at the ATR core mid-plane and at the top of the fueled region to take advantage of the axial cosine distribution of the neutron and gamma flux; and by varying the length of irradiation time of the two capsules. Disassembly of the irradiated capsules and testing of the insulation samples were performed at the Test Reactor Area (TRA) Hot Cell Facilities. Testing of the samples included shear compression static, shear compression fatigue, flexure static, and electrical resistance measurements

  6. Porous silicon formation by hole injection from a back side p+/n junction for electrical insulation applications

    International Nuclear Information System (INIS)

    Fèvre, A; Menard, S; Defforge, T; Gautier, G

    2016-01-01

    In this paper, we propose to study the formation of porous silicon (PS) in low doped (1 × 10 14 cm −3 ) n-type silicon through hole injection from a back side p + /n junction in the dark. This technique is investigated within the framework of electrical insulation. Three different types of junctions are investigated. The first one is an epitaxial n-type layer grown on p + doped silicon wafer. The two other junctions are carried out by boron diffusion leading to p + regions with junction depths of 20 and 115 μm. The resulting PS morphology is a double layer with a nucleation layer (NL) and macropores fully filled with mesoporous material. This result is unusual for low doped n-type silicon. Morphology variations are described depending on the junction formation process, the electrolyte composition, the anodization current density and duration. In order to validate the more interesting industrial potentialities of the p + /n injection technique, a comparison is achieved with back side illumination in terms of resulting morphology and experiments confirm comparable results. Electrical characterizations of the double layer, including NL and fully filled macropores, are then performed. To our knowledge, this is the first electrical investigation in low doped n type silicon with this morphology. Compared to the bulk silicon, the measured electrical resistivities are 6–7 orders of magnitude higher at 373 K. (paper)

  7. 360° tunable microwave phase shifter based on silicon-on-insulator dual-microring resonator

    DEFF Research Database (Denmark)

    Pu, Minhao; Xue, Weiqi; Liu, Liu

    2010-01-01

    We demonstrate tunable microwave phase shifters based on electrically tunable silicon-on-insulator dual-microring resonators. A quasi-linear phase shift of 360° with ~2dB radio frequency power variation at a microwave frequency of 40GHz is obtained......We demonstrate tunable microwave phase shifters based on electrically tunable silicon-on-insulator dual-microring resonators. A quasi-linear phase shift of 360° with ~2dB radio frequency power variation at a microwave frequency of 40GHz is obtained...

  8. Current-induced switching of magnetic molecules on topological insulator surfaces

    Science.gov (United States)

    Locane, Elina; Brouwer, Piet W.

    2017-03-01

    Electrical currents at the surface or edge of a topological insulator are intrinsically spin polarized. We show that such surface or edge currents can be used to switch the orientation of a molecular magnet weakly coupled to the surface or edge of a topological insulator. For the edge of a two-dimensional topological insulator as well as for the surface of a three-dimensional topological insulator the application of a well-chosen surface or edge current can lead to a complete polarization of the molecule if the molecule's magnetic anisotropy axis is appropriately aligned with the current direction. For a generic orientation of the molecule a nonzero but incomplete polarization is obtained. We calculate the probability distribution of the magnetic states and the switching rates as a function of the applied current.

  9. Linear particle accelerator with seal structure between electrodes and insulators

    Science.gov (United States)

    Broadhurst, John H.

    1989-01-01

    An electrostatic linear accelerator includes an electrode stack comprised of primary electrodes formed or Kovar and supported by annular glass insulators having the same thermal expansion rate as the electrodes. Each glass insulator is provided with a pair of fused-in Kovar ring inserts which are bonded to the electrodes. Each electrode is designed to define a concavo-convex particle trap so that secondary charged particles generated within the accelerated beam area cannot reach the inner surface of an insulator. Each insulator has a generated inner surface profile which is so configured that the electrical field at this surface contains no significant tangential component. A spark gap trigger assembly is provided, which energizes spark gaps protecting the electrodes affected by over voltage to prevent excessive energy dissipation in the electrode stack.

  10. Testing of ITER central solenoid coil insulation in an array

    International Nuclear Information System (INIS)

    Jayakumar, R.; Martovetsky, N.N.; Perfect, S.A.

    1995-01-01

    A glass-polyimide insulation system has been proposed by the US team for use in the Central Solenoid (CS) coil of the international Thermonuclear Experimental Reactor (ITER) machine and it is planned to use this system in the CS model coil inner module. The turn insulation will consist of 2 layers of combined prepreg and Kapton. Each layer is 50% overlapped with a butt wrap of prepreg and an overwrap of S glass. The coil layers will be separated by a glass-resin composite and impregnated in a VPI process. Small scale tests on the various components of the insulation are complete. It is planned to fabricate and test the insulation in a 4 x 4 insulated CS conductor array which will include the layer insulation and be vacuum impregnated. The conductor array will be subjected to 20 thermal cycles and 100000 mechanical load cycles in a Liquid Nitrogen environment. These loads are similar to those seen in the CS coil design. The insulation will be electrically tested at several stages during mechanical testing. This paper will describe the array configuration, fabrication: process, instrumentation, testing configuration, and supporting analyses used in selecting the array and test configurations

  11. Influence of LOCA simulating conditions on the variation of electrical characteristics of insulating materials

    Energy Technology Data Exchange (ETDEWEB)

    Okada, Sohei; Yoshikawa, Masato; Ito, Masayuki; Kusama, Yasuo; Yagi, Toshiaki

    1982-12-01

    The authors have examined the variation of insulation resistance when the sheets of insulating materials and cables were exposed to various LOCA simulating environment. This report describes the summarized results obtained so far for ethylene propylene rubber (EPR) which is important as an insulating material of cables. The samples used were an EPR sheet of standard compound ratio, 2 kinds of EPR sheets of practical compound ratio, 6 types of PH cables (fire-retardant, EPR insulated, chlorosulphonated polyethylene sheathed cable) produced for trial as reactor use, and 6 kinds of EPR sheets of the same composition as the cable core. To discuss the difference of insulation resistance change, the logarithmic mean of the ratio of 1 min values to initial insulation resistance rho/rhosub(o) was used. PWR LOCA-simulating environment was used, while the thermal aging in the air at 121 deg C for 7 days and 50 Mrad irradiation in the air at room temperature were given as the predeterioration. The effect of LOCA-simulation period in the simultaneous method without air, in which steam and radiation were given in parallel, the difference in the experimental results of cables and sheets, the effect of air, the comparison of the simultaneous method with the sequential method in which LOCA-simulating steam was applied after the irradiation in the air and the reverse sequential method (dielectric property measurements) are described. Under the existence of air, the sequential method seems to be a good simulation condition for the simultaneous method, though many experiments are required further.

  12. Influence of LOCA simulating conditions on the variation of electrical characteristics of insulating materials

    International Nuclear Information System (INIS)

    Okada, Sohei; Yoshikawa, Masato; Ito, Masayuki; Kusama, Yasuo; Yagi, Toshiaki

    1982-01-01

    The authors have examined the variation of insulation resistance when the sheets of insulating materials and cables were exposed to various LOCA simulating environment. This report describes the summarized results obtained so far for ethylene propylene rubber (EPR) which is important as an insulating material of cables. The samples used were an EPR sheet of standard compound ratio, 2 kinds of EPR sheets of practical compound ratio, 6 types of PH cables (fire-retardant, EPR insulated, chlorosulphonated polyethylene sheathed cable) produced for trial as reactor use, and 6 kinds of EPR sheets of the same composition as the cable core. To discuss the difference of insulation resistance change, the logarithmic mean of the ratio of 1 min values to initial insulation resistance rho/rhosub(o) was used. PWR LOCA-simulating environment was used, while the thermal aging in the air at 121 deg C for 7 days and 50 Mrad irradiation in the air at room temperature were given as the predeterioration. The effect of LOCA-simulation period in the simultaneous method without air, in which steam and radiation were given in parallel, the difference in the experimental results of cables and sheets, the effect of air, the comparison of the simultaneous method with the sequential method in which LOCA-simulating steam was applied after the irradiation in the air and the reverse sequential method (dielectric property measurements) are described. Under the existence of air, the sequential method seems to be a good simulation condition for the simultaneous method, though many experiments are required further. (Wakatsuki, Y.)

  13. Physical processes in high field insulating liquid conduction

    Science.gov (United States)

    Mazarakis, Michael; Kiefer, Mark; Leckbee, Joshua; Anderson, Delmar; Wilkins, Frank; Obregon, Robert

    2017-10-01

    In the power grid transmission where a large amount of energy is transmitted to long distances, High Voltage DC (HVDC) transmission of up to 1MV becomes more attractive since is more efficient than the counterpart AC. However, two of the most difficult problems to solve are the cable connections to the high voltage power sources and their insulation from the ground. The insulating systems are usually composed of transformer oil and solid insulators. The oil behavior under HVDC is similar to that of a weak electrolyte. Its behavior under HVDC is dominated more by conductivity than dielectric constant. Space charge effects in the oil bulk near high voltage electrodes and impeded plastic insulators affect the voltage oil hold-off. We have constructed an experimental facility where we study the oil and plastic insulator behavior in an actual HVDC System. Experimental results will be presented and compared with the present understanding of the physics governing the oil behavior under very high electrical stresses. Sandia National Laboratories managed and operated by National Technology and Engineering Solutions of Sandia, LLC., a wholly owned subsidiary of Honeywell International, Inc., for the U.S. D.O.E., NNSA under contract DE-NA-0003525.

  14. Chemical oxidation of cable insulating oil contaminated soil

    NARCIS (Netherlands)

    Jinlan Xu,; Pancras, T.; Grotenhuis, J.T.C.

    2011-01-01

    Leaking cable insulating oil is a common source of soil contamination of high-voltage underground electricity cables in many European countries. In situ remediation of these contaminations is very difficult, due to the nature of the contamination and the high concentrations present. Chemical

  15. The numerical model of multi-layer insulation with a defined wrapping pattern immersed in superfluid helium

    Science.gov (United States)

    Malecha, Ziemowit; Lubryka, Eliza

    2017-11-01

    The numerical model of thin layers, characterized by a defined wrapping pattern can be a crucial element of many computational problems related to engineering and science. A motivating example is found in multilayer electrical insulation, which is an important component of superconducting magnets and other cryogenic installations. The wrapping pattern of the insulation can significantly affect heat transport and the performance of the considered instruments. The major objective of this study is to develop the numerical boundary conditions (BC) needed to model the wrapping pattern of thin insulation. An example of the practical application of the proposed BC includes the heat transfer of Rutherford NbTi cables immersed in super-fluid helium (He II) across thin layers of electrical insulation. The proposed BC and a mathematical model of heat transfer in He II are implemented in the open source CFD toolbox OpenFOAM. The implemented mathematical model and the BC are compared in the experiments. The study confirms that the thermal resistance of electrical insulation can be lowered by implementing the proper wrapping pattern. The proposed BC can be useful in the study of new patterns for wrapping schemes. The work has been supported by statutory funds from Polish Ministry for Science and Higher Education for the year of 2017.

  16. Edge forward mechanical protection for porcelain insulators

    Energy Technology Data Exchange (ETDEWEB)

    deCasseres, D.K.

    1987-12-01

    Vandal damage to exposed outdoor insulators of all types has become an increasing problem. Porcelain is susceptible to impact fracture, and Area Boards have frequently found it necessary to protect expensive and often highly vulnerable terminating assemblies from the unwelcome attention of hooligans. Various means of physical protection can be used, but many of these are highly demanding in terms of maintenance. This article discusses the 'state of the art' in insulator protection, and describes the design and development of a new concept in the field-the Shed Protector-a number of which are now installed on 132kV sealing ends throughout the Electricity Supply Industry.

  17. An Electrically Switchable Metal-Organic Framework

    Science.gov (United States)

    Fernandez, Carlos A.; Martin, Paul C.; Schaef, Todd; Bowden, Mark E.; Thallapally, Praveen K.; Dang, Liem; Xu, Wu; Chen, Xilin; McGrail, B. Peter

    2014-08-01

    Crystalline metal organic framework (MOF) materials containing interconnected porosity can be chemically modified to promote stimulus-driven (light, magnetic or electric fields) structural transformations that can be used in a number of devices. Innovative research strategies are now focused on understanding the role of chemical bond manipulation to reversibly alter the free volume in such structures of critical importance for electro-catalysis, molecular electronics, energy storage technologies, sensor devices and smart membranes. In this letter, we study the mechanism for which an electrically switchable MOF composed of Cu(TCNQ) (TCNQ = 7,7,8,8-tetracyanoquinodimethane) transitions from a high-resistance state to a conducting state in a reversible fashion by an applied potential. The actual mechanism for this reversible electrical switching is still not understood even though a number of reports are available describing the application of electric-field-induced switching of Cu(TCNQ) in device fabrication.

  18. Structural and electrical properties of Ge(111) films grown on Si(111) substrates and application to Ge(111)-on-Insulator

    Energy Technology Data Exchange (ETDEWEB)

    Sawano, K., E-mail: sawano@tcu.ac.jp [Advanced Research Laboratories, Tokyo City University, 8-15-1 Todoroki, Setagaya-ku, Tokyo (Japan); Hoshi, Y.; Kubo, S. [Advanced Research Laboratories, Tokyo City University, 8-15-1 Todoroki, Setagaya-ku, Tokyo (Japan); Arimoto, K.; Yamanaka, J.; Nakagawa, K. [Center for Crystal Science and Technology, University of Yamanashi, 7 Miyamae-cho, Kofu (Japan); Hamaya, K. [Graduate School of Engineering Science, Osaka University, Toyonaka, Osaka (Japan); Miyao, M. [Department of Electronics, Kyushu University, 744 Motooka, Fukuoka (Japan); Shiraki, Y. [Advanced Research Laboratories, Tokyo City University, 8-15-1 Todoroki, Setagaya-ku, Tokyo (Japan)

    2016-08-31

    Structural and electrical properties of a Ge(111) layer directly grown on a Si(111) substrate are studied. Via optimized two-step growth manner, we form a high-quality relaxed Ge layer, where strain-relieving dislocations are confined close to a Ge/Si interface. Consequently, a density of holes, which unintentionally come from crystal defects, is highly suppressed below 4 × 10{sup 16} cm{sup −3}, which leads to significantly high hole Hall mobility exceeding 1500 cm{sup 2}/Vs at room temperature. By layer transfer of the grown Ge layer, we also fabricate a Ge(111)-on-Insulator, which is a promising template for high-performance Ge-based electronic and photonic devices. - Highlights: • A high-quality Ge layer is epitaxially grown on a Si(111) by two-step growth manner. • Growth conditions, such as growth temperatures, are optimized. • Very high hole mobility is obtained from Ge(111) grown on Si(111). • High-quality thin Ge-on-Insulator with (111) orientation is obtained.

  19. Design of load-to-failure tests of high-voltage insulation breaks for ITER's cryogenic network

    CERN Document Server

    Langeslag, S A E; Aviles Santillana, I; Sgobba, S; Foussat, A

    2015-01-01

    The development of new generation superconducting magnets for fusion research, such as the ITER experiment, is largely based on coils wound with so-called cable-in-conduit conductors. The concept of the cable-in-conduit conductor is based on a direct cooling principle, by supercritical helium, flowing through the central region of the conductor, in close contact with the superconducting strands. Consequently, a direct connection exists between the electrically grounded helium coolant supply line and the highly energised magnet windings. Various insulated regions, constructed out of high-voltage insulation breaks, are put in place to isolate sectors with different electrical potential. In addition to high voltages and significant internal helium pressure, the insulation breaks will experience various mechanical forces resulting from differential thermal contraction phenomena and electro-magnetic loads. Special test equipment was designed, prepared and employed to assess the mechanical reliability of the insul...

  20. Toward the hybrid organic semiconductor FET (HOSFET) electrical and electrochemical characterization of functionalized and unfunctionalized, covalently bound organic monolayers on silicon

    NARCIS (Netherlands)

    Faber, Erik Jouwert

    2006-01-01

    Since their introduction in 1993 the class of covalently bound organic monolayers on oxide free silicon surfaces have found their way to multiple application fields such as passivation layers in solar cells, masking layers in lithographic processing, insulating films in hybrid moleculesilicon

  1. Electrical installations technology

    CERN Document Server

    Whitfield, J F

    1968-01-01

    Electrical Installations Technology covers the syllabus of the City and Guilds of London Institute course No. 51, the "Electricians B Certificate”. This book is composed of 15 chapters that deal with basic electrical science and electrical installations. The introductory chapters discuss the fundamentals and basic electrical principles, including the concept of mechanics, heat, magnetic fields, electric currents, power, and energy. These chapters also explore the atomic theory of electric current and the electric circuit, conductors, and insulators. The subsequent chapter focuses on the chemis

  2. Poly(4-vinylphenol) gate insulator with cross-linking using a rapid low-power microwave induction heating scheme for organic thin-film-transistors

    Science.gov (United States)

    Fan, Ching-Lin; Shang, Ming-Chi; Hsia, Mao-Yuan; Wang, Shea-Jue; Huang, Bohr-Ran; Lee, Win-Der

    2016-03-01

    A Microwave-Induction Heating (MIH) scheme is proposed for the poly(4-vinylphenol) (PVP) gate insulator cross-linking process to replace the traditional oven heating cross-linking process. The cross-linking time is significantly decreased from 1 h to 5 min by heating the metal below the PVP layer using microwave irradiation. The necessary microwave power was substantially reduced to about 50 W by decreasing the chamber pressure. The MIH scheme is a good candidate to replace traditional thermal heating for cross-linking of PVP as the gate insulator for organic thin-film-transistors.

  3. Ferromagnetic-insulators-modulated transport properties on the surface of a topological insulator

    International Nuclear Information System (INIS)

    Guo Jun-Ji; Liao Wen-Hu

    2014-01-01

    Transport properties on the surface of a topological insulator (TI) under the modulation of a two-dimensional (2D) ferromagnet/ferromagnet junction are investigated by the method of wave function matching. The single ferromagnetic barrier modulated transmission probability is expected to be a periodic function of the polarization angle and the planar rotation angle, that decreases with the strength of the magnetic proximity exchange increasing. However, the transmission probability for the double ferromagnetic insulators modulated n—n junction and n—p junction is not a periodic function of polarization angle nor planar rotation angle, owing to the combined effects of the double ferromagnetic insulators and the barrier potential. Since the energy gap between the conduction band and the valence band is narrowed and widened respectively in ranges of 0 ≤ θ < π/2 and π/2 < θ ≤ π, the transmission probability of the n—n junction first increases rapidly and then decreases slowly with the increase of the magnetic proximity exchange strength. While the transmission probability for the n—p junction demonstrates an opposite trend on the strength of the magnetic proximity exchange because the band gaps contrarily vary. The obtained results may lead to the possible realization of a magnetic/electric switch based on TIs and be useful in further understanding the surface states of TIs

  4. High performance organic field-effect transistors with ultra-thin HfO2 gate insulator deposited directly onto the organic semiconductor

    International Nuclear Information System (INIS)

    Ono, S.; Häusermann, R.; Chiba, D.; Shimamura, K.; Ono, T.; Batlogg, B.

    2014-01-01

    We have produced stable organic field-effect transistors (OFETs) with an ultra-thin HfO 2 gate insulator deposited directly on top of rubrene single crystals by atomic layer deposition (ALD). We find that ALD is a gentle deposition process to grow thin films without damaging rubrene single crystals, as results these devices have a negligibly small threshold voltage and are very stable against gate-bias-stress, and the mobility exceeds 1 cm 2 /V s. Moreover, the devices show very little degradation even when kept in air for more than 2 months. These results demonstrate thin HfO 2 layers deposited by ALD to be well suited as high capacitance gate dielectrics in OFETs operating at small gate voltage. In addition, the dielectric layer acts as an effective passivation layer to protect the organic semiconductor

  5. Probable metal-insulator transition in Ag{sub 4}SSe

    Energy Technology Data Exchange (ETDEWEB)

    Drebushchak, V.A., E-mail: dva@igm.nsc.ru [V.S. Sobolev Institute of Geology and Mineralogy, SB RAS, Pr. Ac. Koptyuga 3, Novosibirsk 630090 (Russian Federation); Novosibirsk State University, Ul. Pirogova 2, Novosibirsk 630090 (Russian Federation); Pal’yanova, G.A.; Seryotkin, Yu.V. [V.S. Sobolev Institute of Geology and Mineralogy, SB RAS, Pr. Ac. Koptyuga 3, Novosibirsk 630090 (Russian Federation); Novosibirsk State University, Ul. Pirogova 2, Novosibirsk 630090 (Russian Federation); Drebushchak, T.N. [Novosibirsk State University, Ul. Pirogova 2, Novosibirsk 630090 (Russian Federation); Institute of Solid State Chemistry and Mechanochemistry, SB RAS, Ul. Kutateladze 18, Novosibirsk 630128 (Russian Federation)

    2015-02-15

    Highlights: • New phase transition in Ag{sub 4}SSe was discovered with scanning calorimetry and supported with X-ray powder diffraction. • The thermal effect relates to the anomaly in electrical and thermal conductivity of Ag{sub 4}SSe. • Similar thermal and electrical effects in K{sub 3}Cu{sub 8}S{sub 6} are explained with the metal-insulator transition. - Abstract: New phase transition (285 K) in low-temperature monoclinic Ag{sub 4}SSe was found out below the α-β transition (358 K) after the measurements with differential scanning calorimetry. The transition reveals significant hysteresis (over 30 K). X-ray powder diffraction shows that the superlattice with doubled a and b parameters of the unit cell exists below the new transition point. The signs of this new phase transition can be found in thermal and electrical conductivity of Ag{sub 4}SSe published in literature. Elusive phase transition in Ag{sub 2}Se shows similar properties. The new transition is likely related to the metal-insulator type transition, like K{sub 3}Cu{sub 8}S{sub 6}.

  6. Dielectric and diamagnetic susceptibilities near percolative superconductor-insulator transitions.

    Science.gov (United States)

    Loh, Yen Lee; Karki, Pragalv

    2017-10-25

    Coarse-grained superconductor-insulator composites exhibit a superconductor-insulator transition governed by classical percolation, which should be describable by networks of inductors and capacitors. We study several classes of random inductor-capacitor networks on square lattices. We present a unifying framework for defining electric and magnetic response functions, and we extend the Frank-Lobb bond-propagation algorithm to compute these quantities by network reduction. We confirm that the superfluid stiffness scales approximately as [Formula: see text] as the superconducting bond fraction p approaches the percolation threshold p c . We find that the diamagnetic susceptibility scales as [Formula: see text] below percolation, and as [Formula: see text] above percolation. For models lacking self-capacitances, the electric susceptibility scales as [Formula: see text]. Including a self-capacitance on each node changes the critical behavior to approximately [Formula: see text].

  7. Electric transmission technology

    International Nuclear Information System (INIS)

    Shah, K.R.

    1990-01-01

    Electric transmission technology has matured and can transmit bulk power more reliably and economically than the technology 10 years ago.In 1882, Marcel Depres transmitted 15 kW electric power at 2 kV, using a constant direct current; present transmission voltages have risen to ± 600 kV direct current (DC) and 765 kV alternating current (AC), and it is now possible to transmit bulk electric power at voltages as high as ± 1000 kV DC and 1500 kV AC. Affordable computer systems are now available to optimize transmission reliably. New materials have reduced the bulk of insulation for lines and equipment. New conducting materials and configurations have reduced losses in transmission. Advances in line structures and conductor motion, understanding of flashover characteristics of insulators and air-gaps and electrical performance of lines have resulted in more compact urban transmission lines. (author). 15 refs., 7 tabs., 11 figs

  8. A Solution-Doped Polymer Semiconductor:Insulator Blend for Thermoelectrics

    KAUST Repository

    Kiefer, David; Yu, Liyang; Fransson, Erik; Gó mez, André s; Primetzhofer, Daniel; Amassian, Aram; Campoy-Quiles, Mariano; Mü ller, Christian

    2016-01-01

    Poly(ethylene oxide) is demonstrated to be a suitable matrix polymer for the solution-doped conjugated polymer poly(3-hexylthiophene). The polarity of the insulator combined with carefully chosen processing conditions permits the fabrication of tens of micrometer-thick films that feature a fine distribution of the F4TCNQ dopant:semiconductor complex. Changes in electrical conductivity from 0.1 to 0.3 S cm−1 and Seebeck coefficient from 100 to 60 μV K−1 upon addition of the insulator correlate with an increase in doping efficiency from 20% to 40% for heavily doped ternary blends. An invariant bulk thermal conductivity of about 0.3 W m−1 K−1 gives rise to a thermoelectric Figure of merit ZT ∼ 10−4 that remains unaltered for an insulator content of more than 60 wt%. Free-standing, mechanically robust tapes illustrate the versatility of the developed dopant:semiconductor:insulator ternary blends.

  9. A Solution-Doped Polymer Semiconductor:Insulator Blend for Thermoelectrics

    KAUST Repository

    Kiefer, David

    2016-09-01

    Poly(ethylene oxide) is demonstrated to be a suitable matrix polymer for the solution-doped conjugated polymer poly(3-hexylthiophene). The polarity of the insulator combined with carefully chosen processing conditions permits the fabrication of tens of micrometer-thick films that feature a fine distribution of the F4TCNQ dopant:semiconductor complex. Changes in electrical conductivity from 0.1 to 0.3 S cm−1 and Seebeck coefficient from 100 to 60 μV K−1 upon addition of the insulator correlate with an increase in doping efficiency from 20% to 40% for heavily doped ternary blends. An invariant bulk thermal conductivity of about 0.3 W m−1 K−1 gives rise to a thermoelectric Figure of merit ZT ∼ 10−4 that remains unaltered for an insulator content of more than 60 wt%. Free-standing, mechanically robust tapes illustrate the versatility of the developed dopant:semiconductor:insulator ternary blends.

  10. Influences of Corrosive Sulfur on Copper Wires and Oil-Paper Insulation in Transformers

    Directory of Open Access Journals (Sweden)

    Jian Li

    2011-10-01

    Full Text Available Oil-impregnated paper is widely used in power transmission equipment as a reliable insulation. However, copper sulphide deposition on oil-paper insulation can lead to insulation failures in power transformers. This paper presents the influences of copper sulfur corrosion and copper sulphide deposition on copper wires and oil-paper insulation in power transformers. Thermal aging tests of paper-wrapped copper wires and bare copper wires in insulating oil were carried out at 130 °C and 150 °C in laboratory. The corrosive characteristics of paper-wrapped copper wires and bare copper wires were analyzed. Dielectric properties of insulation paper and insulating oil were also analyzed at different stages of the thermal aging tests using a broadband dielectric spectrometer. Experiments and analysis results show that copper sulfide deposition on surfaces of copper wires and insulation paper changes the surface structures of copper wires and insulation paper. Copper sulfur corrosion changes the dielectric properties of oil-paper insulation, and the copper sulfide deposition greatly reduces the electrical breakdown strength of oil-paper insulation. Metal passivator is capable of preventing copper wires from sulfur corrosion. The experimental results are helpful for investigations for fault diagnosis of internal insulation in power transformers.

  11. Optimisation of Multilayer Insulation an Engineering Approach

    CERN Document Server

    Chorowski, M; Parente, C; Riddone, G

    2001-01-01

    A mathematical model has been developed to describe the heat flux through multilayer insulation (MLI). The total heat flux between the layers is the result of three distinct heat transfer modes: radiation, residual gas conduction and solid spacer conduction. The model describes the MLI behaviour considering a layer-to-layer approach and is based on an electrical analogy, in which the three heat transfer modes are treated as parallel thermal impedances. The values of each of the transfer mode vary from layer to layer, although the total heat flux remains constant across the whole MLI blanket. The model enables the optimisation of the insulation with regard to different MLI parameters, such as residual gas pressure, number of layers and boundary temperatures. The model has been tested with experimental measurements carried out at CERN and the results revealed to be in a good agreement, especially for insulation vacuum between 10-5 Pa and 10-3 Pa.

  12. Phosphorylation states of the (Na+ + K+)-transporting ATPase in preparations from lamb kidney and electric-eel (Electophorus electricus) electric organ.

    Science.gov (United States)

    Harris, W E; Stahl, W L

    1984-01-01

    Phosphorylation states of the (Na+ + K+)-transporting ATPase were studied in highly purified preparations isolated from electric-eel electric organ and from lamb kidney. The steady-state level of phosphorylated lamb kidney enzyme, obtained by reaction with [gamma-32P]ATP, was not appreciably reduced in the presence of ADP unless oligomycin was present. The phosphorylated form of the electric-eel electric-organ enzyme was reduced by at least 95% under the same conditions, suggesting that the E1P state in the kidney enzyme is more transitory than that in electric organ. The level of phosphorylation from [32P]Pi was higher in the lamb kidney preparation than in the electric-organ preparation, and the difference in stimulation of phosphorylation by ouabain in the two preparations was striking. Ouabain increased the level of phosphorylation by 35% in the kidney preparation and 734% in the electric-organ preparation. The E2P state seems to be stabilized by ouabain in the latter preparation. These findings, as well as the different reactivities of the thiol groups to blocking reagents in these preparations, suggest that the tertiary structure in the enzyme isolated from these two sources is different. PMID:6324756

  13. Electrical engineer's reference book

    CERN Document Server

    Laughton, M A

    1985-01-01

    Electrical Engineer's Reference Book, Fourteenth Edition focuses on electrical engineering. The book first discusses units, mathematics, and physical quantities, including the international unit system, physical properties, and electricity. The text also looks at network and control systems analysis. The book examines materials used in electrical engineering. Topics include conducting materials, superconductors, silicon, insulating materials, electrical steels, and soft irons and relay steels. The text underscores electrical metrology and instrumentation, steam-generating plants, turbines

  14. Investigation of the mechanical and electrical properties of superconducting coils

    International Nuclear Information System (INIS)

    Saito, T.; Yamagiwa, T.; Hara, K.; Kojima, Y.; Hosoyama, K.; Mori, A.; Nojima, K.; Okamoto, Y.; Takabayashi, S.; Tanaka, T.

    1994-01-01

    Measurement of elastic (Young's) modulus of the superconducting coil and electrical punch-through test have been performed at LBL to understand the mechanical and electrical properties of the superconducting coils. The authors have investigated the elastic modulus of the superconducting coils with six kinds of insulators (made with polyimide-fiberglass-epoxy and all polyimide insulation with epoxy/polyimide adhesive) at room and liquid nitrogen temperatures using samples made of 10 stacks of superconducting cables. The samples are cured under varying compression to investigate the curing pressure dependence of Young's modulus of the coils with six kinds of the insulation system. The electrical punch-through test has also performed under compression at room and liquid nitrogen temperatures to investigate electrical integrity of the insulated coils. The tensile strength test of four kinds of polyimide films has been performed at various temperatures (between cryogenic and coil curing temperatures) to understand the mechanical properties of the films

  15. Electrical analysis of high dielectric constant insulator and metal gate metal oxide semiconductor capacitors on flexible bulk mono-crystalline silicon

    KAUST Repository

    Ghoneim, Mohamed T.

    2015-06-01

    We report on the electrical study of high dielectric constant insulator and metal gate metal oxide semiconductor capacitors (MOSCAPs) on a flexible ultra-thin (25 μm) silicon fabric which is peeled off using a CMOS compatible process from a standard bulk mono-crystalline silicon substrate. A lifetime projection is extracted using statistical analysis of the ramping voltage (Vramp) breakdown and time dependent dielectric breakdown data. The obtained flexible MOSCAPs operational voltages satisfying the 10 years lifetime benchmark are compared to those of the control MOSCAPs, which are not peeled off from the silicon wafer. © 2014 IEEE.

  16. Structural and electrical evaluation for strained Si/SiGe on insulator

    International Nuclear Information System (INIS)

    Wang Dong; Ii, Seiichiro; Ikeda, Ken-ichi; Nakashima, Hideharu; Ninomiya, Masaharu; Nakamae, Masahiko; Nakashima, Hiroshi

    2006-01-01

    Three strained Si/SiGe on insulator wafers having different Ge fractions were evaluated using dual-metal-oxide-semiconductor (dual-MOS) deep level transient spectroscopy (DLTS) and transmission electron microscopy (TEM) methods. The interface of SiGe/buried oxide (BOX) shows roughness less than 1 nm by high resolution TEM observation. The interface states densities (D it ) of SiGe/BOX are approximately 1 x 10 12 cm -2 eV -1 , which is approximately one order of magnitude higher than that of Si/BOX in a Si on insulator wafer measured as reference by the same method of dual-MOS DLTS. The high D it of SiGe/BOX is not due to interface roughness but due to Ge atoms. The threading dislocations were also clearly observed by TEM and were analyzed

  17. ON THE NEED TO INCREASE THE RELIABILITY OF LINEAR INSULATORS FOR DISTRIBUTION NETWORKS 10-20 KV

    Directory of Open Access Journals (Sweden)

    Yu. N. Shumilov

    2018-02-01

    Full Text Available Introduction. In Ukraine high voltage overhead distribution lines (OL of class 6 and 10 kV are the most extended. Their total length exceeds 280,000 km. More than 95% of the lines are made on line supports from reinforced concrete racks. On all poles of the overhead line, pin insulators are installed. According to the data of operation experience, up to 60-70% of single-phase earth (SPE faults due to «insulation» occurs on VL supports due to damage to line pin insulators, mainly during the thunderstorm period. Problem. Insufficient reliability of pin insulators leads to interruptions in power supply, accidents on the line, accidents in the area of reinforced concrete poles, where in the case of insulator damages, a long process of SPE occurs. Goal. The purpose of the work is to select the design and develop requirements for new linear insulators of 10-20 kV overhead lines that provide high resistance to lightning overvoltages with direct and inductive effects of lightning. Methodology. The research methodology consists in analyzing operational experience, calculating insulator parameters and laboratory tests. Results. Using statistical data on lightning parameters and data on mechanical loads on insulators, the main dimensions of line post insulators have been determined that will ensure their reliable operation under conditions of intense thunderstorm activity and extreme ice and wind loads. Conclusions. The main technical requirements for line post insulators for 10-20 kV distribution lines were formulated. On the 10 kV OL located in areas with increased thunderstorm activity it is recommended to use line post insulators instead of pin-type ones. On the OL-20 kV it is recommended to use only line post insulators. The use of high-lightning-resistant line post insulators on OL-10-20 kV will significantly increase the electrical safety and reliability of power supply to consumers. Increased by 2-3 times the cost of line post insulators in

  18. Mathematical Model of Lifetime Duration at Insulation of Electrical Machines

    Directory of Open Access Journals (Sweden)

    Mihaela Răduca

    2009-10-01

    Full Text Available Abstract. This paper present a mathematical model of lifetime duration at hydro generator stator winding insulation when at hydro generator can be appear the damage regimes. The estimation to make by take of the programming and non-programming revisions, through the introduction and correlation of the new defined notions.

  19. Quantum spin/valley Hall effect and topological insulator phase transitions in silicene

    KAUST Repository

    Tahir, M.

    2013-04-26

    We present a theoretical realization of quantum spin and quantum valley Hall effects in silicene. We show that combination of an electric field and intrinsic spin-orbit interaction leads to quantum phase transitions at the charge neutrality point. This phase transition from a two dimensional topological insulator to a trivial insulating state is accompanied by a quenching of the quantum spin Hall effect and the onset of a quantum valley Hall effect, providing a tool to experimentally tune the topological state of silicene. In contrast to graphene and other conventional topological insulators, the proposed effects in silicene are accessible to experiments.

  20. Quantum spin/valley Hall effect and topological insulator phase transitions in silicene

    KAUST Repository

    Tahir, M.; Manchon, Aurelien; Sabeeh, K.; Schwingenschlö gl, Udo

    2013-01-01

    We present a theoretical realization of quantum spin and quantum valley Hall effects in silicene. We show that combination of an electric field and intrinsic spin-orbit interaction leads to quantum phase transitions at the charge neutrality point. This phase transition from a two dimensional topological insulator to a trivial insulating state is accompanied by a quenching of the quantum spin Hall effect and the onset of a quantum valley Hall effect, providing a tool to experimentally tune the topological state of silicene. In contrast to graphene and other conventional topological insulators, the proposed effects in silicene are accessible to experiments.

  1. Electrical bushing for a superconductor element

    Science.gov (United States)

    Mirebeau, Pierre; Lallouet, Nicolas; Delplace, Sebastien; Lapierre, Regis

    2010-05-04

    The invention relates to an electrical bushing serving to make a connection at ambient temperature to a superconductor element situated in an enclosure at cryogenic temperature. The electrical bushing passes successively through an enclosure at intermediate temperature between ambient temperature and cryogenic temperature, and an enclosure at ambient temperature, and it comprises a central electrical conductor surrounded by an electrically insulating sheath. According to the invention, an electrically conductive screen connected to ground potential surrounds the insulating sheath over a section that extends from the end of the bushing that is in contact with the enclosure at cryogenic temperature at least as far as the junction between the enclosure at intermediate temperature and the enclosure at ambient temperature. The invention is more particularly applicable to making a connection to a superconductor cable.

  2. Topological insulators and superconductors: tenfold way and dimensional hierarchy

    International Nuclear Information System (INIS)

    Ryu, Shinsei; Schnyder, Andreas P; Furusaki, Akira; Ludwig, Andreas W W

    2010-01-01

    It has recently been shown that in every spatial dimension there exist precisely five distinct classes of topological insulators or superconductors. Within a given class, the different topological sectors can be distinguished, depending on the case, by a Z or a Z 2 topological invariant. This is an exhaustive classification. Here we construct representatives of topological insulators and superconductors for all five classes and in arbitrary spatial dimension d, in terms of Dirac Hamiltonians. Using these representatives we demonstrate how topological insulators (superconductors) in different dimensions and different classes can be related via 'dimensional reduction' by compactifying one or more spatial dimensions (in 'Kaluza-Klein'-like fashion). For Z-topological insulators (superconductors) this proceeds by descending by one dimension at a time into a different class. The Z 2 -topological insulators (superconductors), on the other hand, are shown to be lower-dimensional descendants of parent Z-topological insulators in the same class, from which they inherit their topological properties. The eightfold periodicity in dimension d that exists for topological insulators (superconductors) with Hamiltonians satisfying at least one reality condition (arising from time-reversal or charge-conjugation/particle-hole symmetries) is a reflection of the eightfold periodicity of the spinor representations of the orthogonal groups SO(N) (a form of Bott periodicity). Furthermore, we derive for general spatial dimensions a relation between the topological invariant that characterizes topological insulators and superconductors with chiral symmetry (i.e., the winding number) and the Chern-Simons invariant. For lower-dimensional cases, this formula relates the winding number to the electric polarization (d=1 spatial dimensions) or to the magnetoelectric polarizability (d=3 spatial dimensions). Finally, we also discuss topological field theories describing the spacetime theory of

  3. Flashover of a vacuum-insulator interface: A statistical model

    Directory of Open Access Journals (Sweden)

    W. A. Stygar

    2004-07-01

    Full Text Available We have developed a statistical model for the flashover of a 45° vacuum-insulator interface (such as would be found in an accelerator subject to a pulsed electric field. The model assumes that the initiation of a flashover plasma is a stochastic process, that the characteristic statistical component of the flashover delay time is much greater than the plasma formative time, and that the average rate at which flashovers occur is a power-law function of the instantaneous value of the electric field. Under these conditions, we find that the flashover probability is given by 1-exp(-E_{p}^{β}t_{eff}C/k^{β}, where E_{p} is the peak value in time of the spatially averaged electric field E(t, t_{eff}≡∫[E(t/E_{p}]^{β}dt is the effective pulse width, C is the insulator circumference, k∝exp(λ/d, and β and λ are constants. We define E(t as V(t/d, where V(t is the voltage across the insulator and d is the insulator thickness. Since the model assumes that flashovers occur at random azimuthal locations along the insulator, it does not apply to systems that have a significant defect, i.e., a location contaminated with debris or compromised by an imperfection at which flashovers repeatedly take place, and which prevents a random spatial distribution. The model is consistent with flashover measurements to within 7% for pulse widths between 0.5 ns and 10   μs, and to within a factor of 2 between 0.5 ns and 90 s (a span of over 11 orders of magnitude. For these measurements, E_{p} ranges from 64 to 651  kV/cm, d from 0.50 to 4.32 cm, and C from 4.96 to 95.74 cm. The model is significantly more accurate, and is valid over a wider range of parameters, than the J. C. Martin flashover relation that has been in use since 1971 [J. C. Martin on Pulsed Power, edited by T. H. Martin, A. H. Guenther, and M. Kristiansen (Plenum, New York, 1996]. We have generalized the statistical model to estimate the total-flashover probability of an

  4. D.B.S. in disordered insulators

    International Nuclear Information System (INIS)

    Bunch, J.M.

    1976-01-01

    These studies were undertaken in order to determine insulator properties for the CTR program. Most of the d.b.s. studies so far have been with various forms of Al 2 O 3 . Some work using fission neutrons and 15-MeV protons along with some high-energy heavy ions is briefly described. Attempts to measure d.b.s. and other electrical properties are mentioned

  5. Improved Thermal-Insulation Systems for Low Temperatures

    Science.gov (United States)

    Fesmire, James E.; Augustynowicz, Stanislaw D.

    2003-01-01

    Improved thermal-insulation materials and structures and the techniques for manufacturing them are undergoing development for use in low-temperature applications. Examples of low-temperature equipment for which these thermal insulation systems could provide improved energy efficiency include storage tanks for cryogens, superconducting electric-power-transmission equipment, containers for transport of food and other perishable commodities, and cold boxes for low-temperature industrial processes. These systems could also be used to insulate piping used to transfer cryogens and other fluids, such as liquefied natural gas, refrigerants, chilled water, crude oil, or low-pressure steam. The present thermal-insulation systems are layer composites based partly on the older class of thermal-insulation systems denoted generally as multilayer insulation (MLI). A typical MLI structure includes an evacuated jacket, within which many layers of radiation shields are stacked or wrapped close together. Low-thermal-conductivity spacers are typically placed between the reflection layers to keep them from touching. MLI can work very well when a high vacuum level (less than 10(exp-4) torr) is maintained and utmost care is taken during installation, but its thermal performance deteriorates sharply as the pressure in the evacuated space rises into the soft vacuum range [pressures greater than 0.1 torr (greater than 13 Pa)]. In addition, the thermal performance of MLI is extremely sensitive to mechanical compression and edge effects and can easily decrease from one to two orders of magnitude from its ideal value even when the MLI is kept under high vacuum condition. The present thermal-insulation systems are designed to perform well under soft vacuum level, in particular the range of 1 to 10 torr. They are also designed with larger interlayer spacings to reduce vulnerability to compression (and consequent heat leak) caused by installation and use. The superiority of these systems is the

  6. 78 FR 41339 - Electric Reliability Organization Proposal To Retire Requirements in Reliability Standards

    Science.gov (United States)

    2013-07-10

    ...] Electric Reliability Organization Proposal To Retire Requirements in Reliability Standards AGENCY: Federal... Reliability Standards identified by the North American Electric Reliability Corporation (NERC), the Commission-certified Electric Reliability Organization. FOR FURTHER INFORMATION CONTACT: Kevin Ryan (Legal Information...

  7. Non-volatile resistive switching in the Mott insulator (V1-xCrx)2O3

    Science.gov (United States)

    Querré, M.; Tranchant, J.; Corraze, B.; Cordier, S.; Bouquet, V.; Députier, S.; Guilloux-Viry, M.; Besland, M.-P.; Janod, E.; Cario, L.

    2018-05-01

    The discovery of non-volatile resistive switching in Mott insulators related to an electric-field-induced insulator to metal transition (IMT) has paved the way for their use in a new type of non-volatile memories, the Mott memories. While most of the previous studies were dedicated to uncover the resistive switching mechanism and explore the memory potential of chalcogenide Mott insulators, we present here a comprehensive study of resistive switching in the canonical oxide Mott insulator (V1-xCrx)2O3. Our work demonstrates that this compound undergoes a non-volatile resistive switching under electric field. This resistive switching is induced by a Mott transition at the local scale which creates metallic domains closely related to existing phases of the temperature-pressure phase diagram of (V1-xCrx)2O3. Our work demonstrates also reversible resistive switching in (V1-xCrx)2O3 crystals and thin film devices. Preliminary performances obtained on 880 nm thick layers with 500 nm electrodes show the strong potential of Mott memories based on the Mott insulator (V1-xCrx)2O3.

  8. Effect of ZrO2 on the sintering behavior, strength and high-frequency dielectric properties of electrical ceramic porcelain insulator

    Science.gov (United States)

    Singh Mehta, Niraj; Sahu, Praveen Kumar; Ershad, Md; Saxena, Vipul; Pyare, Ram; Ranjan Majhi, Manas

    2018-01-01

    In the present study, the effect of ZrO2 on the sintering, strength and dielectric behavior of electrical ceramic porcelain insulator with substituting alumina content by zirconia (in weight percentage from 0% to 30%) is investigated. The different composition of samples containing different zirconia (ZrO2) contents of 0, 10, 20, and 30 wt% are prepared using the uniaxial pressure technique applying 160 MPa pressure. Further, the prepared samples are also analyzed for sintering temperatures (1350 °C), and effects are observed on mechanical and electric properties of porcelain insulator. Different characterizations such as Dilatometer, x-ray diffraction, scanning electron microscopy and differential thermal analysis/thermo gravimetric analysis were used to evaluate the thermal, phase detection, micro structural and weight loss changes by increasing concentration of ZrO2 on base porcelain composition. At 1350 °C, for the composition having 20 wt% ZrO2 with 10 wt% alumina, the maximum density was observed 2.81 g cm-3 with a porosity of 2.23%. The highest tensile strength of 41 ± 3 MPa is observed for the same sample composition. The minimum value of thermal expansion coefficient is found to be in the range of 10-6 for the sample with 30 wt% ZrO2 content sintered at 1350 °C compared to other prepared samples. Similarly, the highest dielectric value (5.1-4.4) having dielectric loss (0.08-0.12) is achieved for the sample with 30 wt% ZrO2 content sintered at 1350 °C in the frequency range of 4-20 GHz at room temperature. According to the mechanical properties, the composition having 20 wt% ZrO2 on base ceramic porcelain composition has enormous potential to serve as a high strength refractory material. For dielectric properties, the composition having 30 wt% ZrO2 is more suitable for the electrical application.

  9. Poly(4-vinylphenol gate insulator with cross-linking using a rapid low-power microwave induction heating scheme for organic thin-film-transistors

    Directory of Open Access Journals (Sweden)

    Ching-Lin Fan

    2016-03-01

    Full Text Available A Microwave-Induction Heating (MIH scheme is proposed for the poly(4-vinylphenol (PVP gate insulator cross-linking process to replace the traditional oven heating cross-linking process. The cross-linking time is significantly decreased from 1 h to 5 min by heating the metal below the PVP layer using microwave irradiation. The necessary microwave power was substantially reduced to about 50 W by decreasing the chamber pressure. The MIH scheme is a good candidate to replace traditional thermal heating for cross-linking of PVP as the gate insulator for organic thin-film-transistors.

  10. Insulation Cork Boards—Environmental Life Cycle Assessment of an Organic Construction Material

    Science.gov (United States)

    Silvestre, José D.; Pargana, Nuno; de Brito, Jorge; Pinheiro, Manuel D.; Durão, Vera

    2016-01-01

    Envelope insulation is a relevant technical solution to cut energy consumption and reduce environmental impacts in buildings. Insulation Cork Boards (ICB) are a natural thermal insulation material whose production promotes the recycling of agricultural waste. The aim of this paper is to determine and evaluate the environmental impacts of the production, use, and end-of-life processing of ICB. A “cradle-to-cradle” environmental Life Cycle Assessment (LCA) was performed according to International LCA standards and the European standards on the environmental evaluation of buildings. These results were based on site-specific data and resulted from a consistent methodology, fully described in the paper for each life cycle stage: Cork oak tree growth, ICB production, and end-of-life processing-modeling of the carbon flows (i.e., uptakes and emissions), including sensitivity analysis of this procedure; at the production stage—the modeling of energy processes and a sensitivity analysis of the allocation procedures; during building operation—the expected service life of ICB; an analysis concerning the need to consider the thermal diffusivity of ICB in the comparison of the performance of insulation materials. This paper presents the up-to-date “cradle-to-cradle” environmental performance of ICB for the environmental categories and life-cycle stages defined in European standards. PMID:28773516

  11. Insulation Cork Boards-Environmental Life Cycle Assessment of an Organic Construction Material.

    Science.gov (United States)

    Silvestre, José D; Pargana, Nuno; de Brito, Jorge; Pinheiro, Manuel D; Durão, Vera

    2016-05-20

    Envelope insulation is a relevant technical solution to cut energy consumption and reduce environmental impacts in buildings. Insulation Cork Boards (ICB) are a natural thermal insulation material whose production promotes the recycling of agricultural waste. The aim of this paper is to determine and evaluate the environmental impacts of the production, use, and end-of-life processing of ICB. A "cradle-to-cradle" environmental Life Cycle Assessment (LCA) was performed according to International LCA standards and the European standards on the environmental evaluation of buildings. These results were based on site-specific data and resulted from a consistent methodology, fully described in the paper for each life cycle stage: Cork oak tree growth, ICB production, and end-of-life processing-modeling of the carbon flows ( i.e. , uptakes and emissions), including sensitivity analysis of this procedure; at the production stage-the modeling of energy processes and a sensitivity analysis of the allocation procedures; during building operation-the expected service life of ICB; an analysis concerning the need to consider the thermal diffusivity of ICB in the comparison of the performance of insulation materials. This paper presents the up-to-date "cradle-to-cradle" environmental performance of ICB for the environmental categories and life-cycle stages defined in European standards.

  12. Insulation Cork Boards—Environmental Life Cycle Assessment of an Organic Construction Material

    Directory of Open Access Journals (Sweden)

    José D. Silvestre

    2016-05-01

    Full Text Available Envelope insulation is a relevant technical solution to cut energy consumption and reduce environmental impacts in buildings. Insulation Cork Boards (ICB are a natural thermal insulation material whose production promotes the recycling of agricultural waste. The aim of this paper is to determine and evaluate the environmental impacts of the production, use, and end-of-life processing of ICB. A “cradle-to-cradle” environmental Life Cycle Assessment (LCA was performed according to International LCA standards and the European standards on the environmental evaluation of buildings. These results were based on site-specific data and resulted from a consistent methodology, fully described in the paper for each life cycle stage: Cork oak tree growth, ICB production, and end-of-life processing-modeling of the carbon flows (i.e., uptakes and emissions, including sensitivity analysis of this procedure; at the production stage—the modeling of energy processes and a sensitivity analysis of the allocation procedures; during building operation—the expected service life of ICB; an analysis concerning the need to consider the thermal diffusivity of ICB in the comparison of the performance of insulation materials. This paper presents the up-to-date “cradle-to-cradle” environmental performance of ICB for the environmental categories and life-cycle stages defined in European standards.

  13. Fabrication of combinatorial nm-planar electrode array for high throughput evaluation of organic semiconductors

    International Nuclear Information System (INIS)

    Haemori, M.; Edura, T.; Tsutsui, K.; Itaka, K.; Wada, Y.; Koinuma, H.

    2006-01-01

    We have fabricated a combinatorial nm-planar electrode array by using photolithography and chemical mechanical polishing processes for high throughput electrical evaluation of organic devices. Sub-nm precision was achieved with respect to the average level difference between each pair of electrodes and a dielectric layer. The insulating property between the electrodes is high enough to measure I-V characteristics of organic semiconductors. Bottom-contact field-effect-transistors (FETs) of pentacene were fabricated on this electrode array by use of molecular beam epitaxy. It was demonstrated that the array could be used as a pre-patterned device substrate for high throughput screening of the electrical properties of organic semiconductors

  14. Failure criteria for low-temperature irradiated organic composite insulation systems

    International Nuclear Information System (INIS)

    Schutz, J.B.; Fabian, P.E.

    1997-01-01

    Composite insulation systems in fusion magnet applications are often subjected to conditions of combined through thickness compression and shear at varying stress ratios. Characterization of insulation system strength under these conditions requires unidirectional shear and compression tests, as well as biaxial shear/compression testing to define the systems failure envelope. An appropriate failure criteria would reduce the number of tests required to define this envelope, and would give designers a better estimate of material strengths at intermediate stress ratios. Biaxial shear/compression testing requires the use of metallic sandwich specimens, which are susceptible to activation during irradiation. A reliable failure criteria which eliminates the need for biaxial characterization would also reduce the difficulty and expense involved in radiation effects characterization while still providing a complete failure envelope. Several generalized failure criteria, taken from classical composites analysis, were reformulated for application in the shear/compression quadrant. The maximum stress and Tsai-Hill criteria were found to be inadequate to represent the biaxial failure envelope. The generalized Tsai-Wu tensor quadratic failure criterion was also examined. Application of this criterion requires through thickness tensile strength data. Through thickness tensile strengths of insulation systems have not been routinely characterized, but limited data are available. Utilizing unidirectional through thickness tension, compression, and interlaminar shear strength data, the Tsai-Wu failure criteria was found to agree well with biaxial shear/compression test data

  15. Electron beam assisted field evaporation of insulating nanowires/tubes

    Energy Technology Data Exchange (ETDEWEB)

    Blanchard, N. P., E-mail: nicholas.blanchard@univ-lyon1.fr; Niguès, A.; Choueib, M.; Perisanu, S.; Ayari, A.; Poncharal, P.; Purcell, S. T.; Siria, A.; Vincent, P. [Institut Lumière Matière, UMR5306 Université Lyon 1-CNRS, Université de Lyon, 69622 Villeurbanne Cedex (France)

    2015-05-11

    We demonstrate field evaporation of insulating materials, specifically BN nanotubes and undoped Si nanowires, assisted by a convergent electron beam. Electron irradiation leads to positive charging at the nano-object's apex and to an important increase of the local electric field thus inducing field evaporation. Experiments performed both in a transmission electron microscope and in a scanning electron microscope are presented. This technique permits the selective evaporation of individual nanowires in complex materials. Electron assisted field evaporation could be an interesting alternative or complementary to laser induced field desorption used in atom probe tomography of insulating materials.

  16. Electric-Field-Induced Superconductivity Detected by Magnetization Measurements of an Electric-Double-Layer Capacitor

    NARCIS (Netherlands)

    Kasahara, Yuichi; Nishijima, Takahiro; Sato, Tatsuya; Takeuchi, Yuki; Ye, Jianting; Yuan, Hongtao; Shimotani, Hidekazu; Iwasa, Yoshihiro

    We report evidence for superconductivity induced by the application of strong electric fields onto the surface of a band insulator, ZrNCl, provided by the observation of a shielding diamagnetic signal. We introduced an electric-double-layer capacitor configuration and in situ magnetization

  17. Synthesis and characterization of innovative insulation materials

    Directory of Open Access Journals (Sweden)

    Skaropoulou Aggeliki

    2018-01-01

    Full Text Available Insulation elements are distinguished in inorganic fibrous and organic foamed materials. Foamed insulation materials are of great acceptance and use, but their major disadvantage is their flammability. In case of fire, they tend to transmit the flame producing toxic gases. In this paper, the synthesis and characterization of innovative inorganic insulation materials with properties competitive to commercial is presented. Their synthesis involves the mixing of inorganic raw material and water with reinforcing agent or/and foaming agent leading to the formation of a gel. Depending on raw materials nature, the insulation material is produced by freeze drying or ambient drying techniques of the gel. The raw material used are chemically benign and abundantly available materials, or industrial by-products and the final products are non-toxic and, in some cases, non-flammable. Their density and thermal conductivity was measured and found 0.02-0.06 g/cm3 and 0.03-0.04 W/mK, respectively.

  18. 76 FR 58101 - Electric Reliability Organization Interpretation of Transmission Operations Reliability Standard

    Science.gov (United States)

    2011-09-20

    ....C. Cir. 2009). \\4\\ Mandatory Reliability Standards for the Bulk-Power System, Order No. 693, FERC... for maintaining real and reactive power balance. \\14\\ Electric Reliability Organization Interpretation...; Order No. 753] Electric Reliability Organization Interpretation of Transmission Operations Reliability...

  19. Effect on the insulation material of a MOSFET device submitted to a standard diagnostic radiation beam

    International Nuclear Information System (INIS)

    De Magalhaes, C M S; Dos Santos, L A P; Souza, D do N; Maia, A F

    2010-01-01

    MOSFET electronic devices have been used for dosimetry in radiology and radiotherapy. Several communications show that due to the radiation exposure defects appear on the semiconductor crystal lattice. Actually, the structure of a MOSFET consists of three materials: a semiconductor, a metal and an insulator between them. The MOSFET is a quadripolar device with a common terminal: gate-source is the input; drain-source is the output. The gate controls the electrical current passing through semiconductor medium by the field effect because the silicon oxide acts as insulating material. The proposal of this work is to show some radiation effects on the insulator of a MOSFET device. A 6430 Keithley sub-femtoamp SourceMeter was used to verify how the insulating material layer in the structure of the device varies with the radiation exposure. We have used the IEC 61267 standard radiation X-ray beams generated from a Pantak industrial unit in the radiation energy range of computed tomography. This range was chosen because we are using the MOSFET device as radiation detector for dosimetry in computed tomography. The results showed that the behaviour of the electrical current of the device is different in the insulator and semiconductor structures.

  20. Time-resolved terahertz spectroscopy of electrically conductive metal-organic frameworks doped with redox active species

    Science.gov (United States)

    Alberding, Brian G.; Heilweil, Edwin J.

    2015-09-01

    Metal-Organic Frameworks (MOFs) are three-dimensional coordination polymers that are well known for large pore surface area and their ability to adsorb molecules from both the gaseous and solution phases. In general, MOFs are electrically insulating, but promising opportunities for tuning the electronic structure exist because MOFs possess synthetic versatility; the metal and organic ligand subunits can be exchanged or dopant molecules can be introduced into the pore space. Two such MOFs with demonstrated electrical conductivity are Cu3(1,3,5-benzenetricarboxylate)2, a.k.a HKUST-1, and Cu[Ni(pyrazine-2,3-dithiolate)2]. Herein, these two MOFs have been infiltrated with the redox active species 7,7,8,8-tetracyanoquinodimethane (TCNQ) and iodine under solution phase conditions and shown to produce redox products within the MOF pore space. Vibrational bands assignable to TCNQ anion and triiodide anion have been observed in the Mid-IR and Terahertz ranges using FTIR Spectroscopy. The MOF samples have been further investigated by Time-Resolved Terehertz Spectroscopy (TRTS). Using this technique, the charge mobility, separation, and recombination dynamics have been followed on the picosecond time scale following photoexcitation with visible radiation. The preliminary results show that the MOF samples have small inherent photoconductivity with charge separation lifetimes on the order of a few picoseconds. In the case of HKUST-1, the MOF can also be supported by a TiO2 film and initial results show that charge injection into the TiO2 layer occurs with a comparable efficiency to the dye sensitizer N3, [cis-Bis(isothiocyanato)-bis(2,2'-bipyridyl-4,4'-dicarboxylato ruthenium(II)], and therefore this MOF has potential as a new light absorbing and charge conducting material in photovoltaic devices.

  1. Electrohydrodynamic Direct-Write Orderly Micro/Nanofibrous Structure on Flexible Insulating Substrate

    Directory of Open Access Journals (Sweden)

    Jiang-Yi Zheng

    2014-01-01

    Full Text Available AC pulse-modulated electrohydrodynamic direct-writing (EDW was utilized to direct-write orderly micro/nanofibrous structure on the flexible insulating polyethylene terephthalate (PET substrate. During the EDW process, AC electrical field induced charges to reciprocate along the jet and decreased the charge repulsive force that applied on charged jet. Thanks to the smaller charge repulsive force, stable straight jet can be built up to direct-write orderly micro/nanofibrous structures on the insulating substrate. The minimum motion velocity required to direct-write straight line fibrous structure on insulating PET substrate was 700 mm/s. Moreover, the influences of AC voltage amplitude, frequency, and duty cycle ratio on the line width of fibrous structures were investigated. This work proposes a novel solution to overcome the inherent charge repulsion emerging on the insulating substrate, and promotes the application of EDW technology on the flexible electronics.

  2. The electro-mechanical effect from charge dynamics on polymeric insulation lifetime

    Science.gov (United States)

    Alghamdi, H.; Chen, G.; Vaughan, A. S.

    2015-12-01

    For polymeric material used as electrical insulation, the presence of space charges could be the consequence of material degradations that are thermally activated but increased by the application of an electric field. The dynamics of space charge, therefore, can be potentially used to characterize the material. In this direction, a new aging model in which parameters have clear physical meanings has been developed and applied to the material to extrapolate the lifetime. The kinetic equation has been established based on charge trapping and detrapping of the injected charge from the electrodes. The local electromechanical energy stored in the region surrounding the trap is able to reduce the trap-depth with a value related to the electric field. At a level where the internal electric field exceeds the detrapping field in the material, an electron can be efficiently detrapped and the released energy from detrapping process can cause a weak bond or chain scission i.e. material degradation. The model has been applied to the electro-thermally aged low density polyethylene film samples, showing well fitted result, as well as interesting relationships between parameter estimates and insulation morphology.

  3. Systems and methods for the magnetic insulation of accelerator electrodes in electrostatic accelerators

    Science.gov (United States)

    Grisham, Larry R

    2013-12-17

    The present invention provides systems and methods for the magnetic insulation of accelerator electrodes in electrostatic accelerators. Advantageously, the systems and methods of the present invention improve the practically obtainable performance of these electrostatic accelerators by addressing, among other things, voltage holding problems and conditioning issues. The problems and issues are addressed by flowing electric currents along these accelerator electrodes to produce magnetic fields that envelope the accelerator electrodes and their support structures, so as to prevent very low energy electrons from leaving the surfaces of the accelerator electrodes and subsequently picking up energy from the surrounding electric field. In various applications, this magnetic insulation must only produce modest gains in voltage holding capability to represent a significant achievement.

  4. Treeing phenomenon of thermoplastic polyethylene blends for recyclable cable insulation materials

    Science.gov (United States)

    Li, Lunzhi; Zhang, Kai; Zhong, Lisheng; Gao, Jinghui; Xu, Man; Chen, Guanghui; Fu, Mingli

    2017-02-01

    Owing to its good recyclability and low processing energy consumption, non-crosslinked polyethylene blends (e.g. LLDPE-HDPE blends) are considered as one of potential environmental-friendly substitutions for crosslinked polyethylene (XLPE) as cable insulation material. Although extensive work has been performed for measuring the basic dielectric properties, there is a lack of the investigations on the aging properties for such a material system, which hinders the evaluation of reliability and lifetime of the material for cable insulation. In this paper, we study the electric aging phenomenon of 0.7LLDPE-0.3HDPE blending material by investigating the treeing behavior, and its comparison with XLPE and LLDPE. Treeing tests show that the 0.7LLDPE-0.3HDPE blends have lower probability for treeing as well as smaller treeing dimensions. Further thermal analysis and microstructure study results suggest that the blends exhibit larger proportion of thick lamellae and higher crystallinity with homogeneously-distributed amorphous region, which is responsible for good anti-treeing performance. Our finding provides the evidence that the 0.7LLDPE-0.3HDPE blends exhibits better electric-aging-retardance properties than XLPE, which may result in a potential application for cable insulation.

  5. Treeing phenomenon of thermoplastic polyethylene blends for recyclable cable insulation materials

    Directory of Open Access Journals (Sweden)

    Lunzhi Li

    2017-02-01

    Full Text Available Owing to its good recyclability and low processing energy consumption, non-crosslinked polyethylene blends (e.g. LLDPE-HDPE blends are considered as one of potential environmental-friendly substitutions for crosslinked polyethylene (XLPE as cable insulation material. Although extensive work has been performed for measuring the basic dielectric properties, there is a lack of the investigations on the aging properties for such a material system, which hinders the evaluation of reliability and lifetime of the material for cable insulation. In this paper, we study the electric aging phenomenon of 0.7LLDPE-0.3HDPE blending material by investigating the treeing behavior, and its comparison with XLPE and LLDPE. Treeing tests show that the 0.7LLDPE-0.3HDPE blends have lower probability for treeing as well as smaller treeing dimensions. Further thermal analysis and microstructure study results suggest that the blends exhibit larger proportion of thick lamellae and higher crystallinity with homogeneously-distributed amorphous region, which is responsible for good anti-treeing performance. Our finding provides the evidence that the 0.7LLDPE-0.3HDPE blends exhibits better electric-aging-retardance properties than XLPE, which may result in a potential application for cable insulation.

  6. Manufacture of mineral-insulated conductor for ITER prototype ELM and VS coil

    International Nuclear Information System (INIS)

    Long, Feng; Wu, Yu; Jin, Huan; Yu, Min; Han, Qiyang; Ling, Feng; Kalish, Michael

    2015-01-01

    Highlights: • Compaction method is successfully developed for MIC manufacture. • Manufactured MICs show well controlled outer diameter and good electrical properties. • Insulation resistance of all the MICs is higher than 100 GΩ@DC 2500 V. - Abstract: An ITER Organization (IO) Task Agreement (TA) “Final Design and Prototyping of the ITER In-Vessel Coils (IVC) and Feeders” is almost finished by Institute of Plasma Physics, Chinese Academy of Sciences (ASIPP). ITER IVCs consist of edge-localized mode (ELM) and vertical stabilization (VS) coils. One prototype Mid-ELM coil complete with 19 brackets brazed with the conductors and one prototype 120° section of upper VS coil with structural components brazed to the conductors have been fabricated. Compaction method is developed successfully for the mineral-insulated conductor (MIC) manufacture. Approximate 110 m Inconel 625 jacket MICs for Mid-ELM prototype coil and 80 m stainless steel 316L jacket MICs for VS prototype coil were manufactured. Most of the copper tubes used for the MICs fabrication failed the ultrasonic testing (UT), but the jacket tubes have good passing rate. Manufacture processes and inspection for the MICs are presented in this paper

  7. Manufacture of mineral-insulated conductor for ITER prototype ELM and VS coil

    Energy Technology Data Exchange (ETDEWEB)

    Long, Feng, E-mail: longf@ipp.ac.cn [Institute of Plasma Physics of Chinese Academy of Sciences, Hefei 230031 (China); Wu, Yu; Jin, Huan; Yu, Min; Han, Qiyang; Ling, Feng [Institute of Plasma Physics of Chinese Academy of Sciences, Hefei 230031 (China); Kalish, Michael [Princeton Plasma Physics Laboratory, PO Box 451, Princeton, NJ 08543 (United States)

    2015-06-15

    Highlights: • Compaction method is successfully developed for MIC manufacture. • Manufactured MICs show well controlled outer diameter and good electrical properties. • Insulation resistance of all the MICs is higher than 100 GΩ@DC 2500 V. - Abstract: An ITER Organization (IO) Task Agreement (TA) “Final Design and Prototyping of the ITER In-Vessel Coils (IVC) and Feeders” is almost finished by Institute of Plasma Physics, Chinese Academy of Sciences (ASIPP). ITER IVCs consist of edge-localized mode (ELM) and vertical stabilization (VS) coils. One prototype Mid-ELM coil complete with 19 brackets brazed with the conductors and one prototype 120° section of upper VS coil with structural components brazed to the conductors have been fabricated. Compaction method is developed successfully for the mineral-insulated conductor (MIC) manufacture. Approximate 110 m Inconel 625 jacket MICs for Mid-ELM prototype coil and 80 m stainless steel 316L jacket MICs for VS prototype coil were manufactured. Most of the copper tubes used for the MICs fabrication failed the ultrasonic testing (UT), but the jacket tubes have good passing rate. Manufacture processes and inspection for the MICs are presented in this paper.

  8. A New Ultra Fast Conduction Mechanism in Insulating Polymer Nanocomposites

    Directory of Open Access Journals (Sweden)

    M. Xu

    2011-01-01

    Full Text Available A brand new phenomenon, namely, electrical conduction via soliton-like ultra fast space charge pulses, recently identified in unfilled cross-linked polyethylene, is shown for the first time to occur in insulating polymer nanocomposites and its characteristics correlated with the electromechanical properties of nanostructured materials. These charge pulses are observed to cross the insulation under low electrical field in epoxy-based nanocomposites containing nanosilica particles with relative weights of 1%, 5%, 10%, and 20% at speeds orders of magnitude higher than those expected for carriers in insulating polymers. The characteristics of mobility, magnitude and repetition rate for both positive and negative charge pulses are studied in relation to nanofiller concentration. The results show that the ultra fast charge pulses (packets are affected significantly by the concentration of nanoparticles. An explanation is presented in terms of a new conduction mechanism where the mechanical properties of the polymer and movement of polymer chains play an important role in the injection and transport of charge in the form of pulses. Here, the charge transport is not controlled by traps. Instead, it is driven by the contribution of polarization and the resultant electromechanical compression, which is substantially affected by the introduction of nanoparticles into the base polymer.

  9. NDE of ceramic insulator blanks by radiography

    International Nuclear Information System (INIS)

    Sarvanan, S.; Venkatraman, B.; Jayakumar, T.; Baldev Raj

    1996-01-01

    The production of ceramic insulators in electrical industry involves a number of steps, one of which is the green blank. The defects such as voids and crack can be present in the extruded green blank. One of the best non-destructive evaluation (NDE) technique radiography. This paper deals with the development of methodology based on theoretical modeling for the examination of ceramics by high sensitivity radiography. (author)

  10. Optimization of electron beam crosslinking of wire and cable insulation

    International Nuclear Information System (INIS)

    Zimek, Z.; Przybytniak, G.; Nowicki, A.

    2011-01-01

    Complete text of publication follows. The computer simulations based on Monte Carlo method and the ModeCEB software program were carried out in connection with EB radiation set-up for crosslinking of electrical wire and cable insulation, located at the Center for Radiation Research and Technology of the Institute of Nuclear Chemistry and Technology. The theoretical predictions for absorbed dose distribution in irradiated electrical wire and cable insulation caused by scanned EB were compared to the experimental results of irradiation which were carried out in the experimental set-up based on ILU 6 electron accelerator, which is characterized by the following parameters: Electron energy 0.5-2.0 MeV; Average beam current 40-10 mA, pulse duration 400 μs; Width of scanning up to 80 cm; Scan frequency up to 50 Hz. The computer simulation of the dose distributions in two-sided irradiation system by a scanned electron beam in multilayer circular objects was performed for different process parameters; electrical wire and cable geometry (thickness of insulation layers and cupper wire diameter), type of polymer isolation, electron energy, energy spread, geometry of electron beam and electrical wire and cable distribution at irradiation zone. The geometry of electron beam distribution in irradiation zone was measured using TVA and PVC foil dosimeters for electron energy range available in ILU 6 accelerator. The temperature rise of irradiated electrical wire and irradiation homogeneity were evaluated for different experimental conditions to optimize process parameters. The obtained results of computer simulation were supported by experimental data of dose distribution based on gel-fraction measurements. Such agreement indicates that computer simulation ModeCEB is correct and sufficient for modelling of absorbed dose distribution in multi-layer circular objects irradiated with scanned electron beams. Acknowledgement: The R and D activities are supported by the European

  11. Breakdown characteristics of SF6/N2 in severely non-uniform electric fields at low temperatures

    Science.gov (United States)

    Wang, Y.; Gao, Z. W.; Li, G. X.; Zhu, X. C.; Yu, C. L.; Liang, J. Q.; Li, L.

    2018-01-01

    SF6 has good electrical insulating properties, which is widely used as an insulating medium of GIS, GIL and other electrical equipment. However, the reliability of electrical equipments´ insulated gas is greatly challenged in cold areas, since SF6 more readily liquefies. To solve the problem, SF6 can be mixed with N2 to maintain the insulating properties, and reduce its liquefaction temperature. Such practice has certain application prospect. In this paper, a breakdown experimental platform was built to study the insulating property of SF6/N2 at low temperature, wherein the temperature of the platform can be adjusted. A severely non-uniform electric field was generated by a rod-plate electrode. The breakdown characteristics of SF6/N2 with different mixing proportions at low pressures and low temperatures were measured. The result showed that the mixed gas was not liquefied within the temperature range. Temperature had insignificant influence on the insulating property thereof. The result in the paper has certain guiding significance for applying SF6/N2 mixed gas in high latitude areas.

  12. Development of Electrical Breakdown in Transformer Oil

    Directory of Open Access Journals (Sweden)

    Jozef Kudelcik

    2006-01-01

    Full Text Available Power transformers are key equipment for transfer and distribution of the electric power. Considering the significance of the power transformers in the electric system, their price and possible damages occurred by accidents, it is necessary to pay attention to their higher prevention. To prevent failure states of transformers, we perform different types ofmeasurements. They shall illustrate a momentary state of the measured equipment and if necessary to draw attention in advance to changes of parameters, which have specific relationship to no-failure operation of the equipment. The conditions under which breakdown of composite liquid/ solid insulation can occur, e.g. in transformer, play an important role in designing such insulation. The liquid, mainly mineral oil, generally constitutes the weakest part of insulation and a great amount of work has been devoted to the study of streamers, which appear in the gaseous phase, and most often are triggering the failure of insulation.

  13. Stability Study of Flexible 6,13-Bis(triisopropylsilylethynylpentacene Thin-Film Transistors with a Cross-Linked Poly(4-vinylphenol/Yttrium Oxide Nanocomposite Gate Insulator

    Directory of Open Access Journals (Sweden)

    Jin-Hyuk Kwon

    2016-03-01

    Full Text Available We investigated the electrical and mechanical stability of flexible 6,13-bis(triisopropylsilylehtynylpentacene (TIPS-pentacene thin-film transistors (TFTs that were fabricated on polyimide (PI substrates using cross-linked poly(4-vinylphenol (c-PVP and c-PVP/yttrium oxide (Y2O3 nanocomposite films as gate insulators. Compared with the electrical characteristics of TIPS-pentacene TFTs with c-PVP insulators, the TFTs with c-PVP/Y2O3 nanocomposite insulators exhibited enhancements in the drain current and the threshold voltage due to an increase in the dielectric capacitance. In electrical stability experiments, a gradual decrease in the drain current and a negative shift in the threshold voltage occurred during prolonged bias stress tests, but these characteristic variations were comparable for both types of TFT. On the other hand, the results of mechanical bending tests showed that the characteristic degradation of the TIPS-pentacene TFTs with c-PVP/Y2O3 nanocomposite insulators was more critical than that of the TFTs with c-PVP insulators. In this study, the detrimental effect of the nanocomposite insulator on the mechanical stability of flexible TIPS-pentacene TFTs was found to be caused by physical adhesion of TIPS-pentacene molecules onto the rough surfaces of the c-PVP/Y2O3 nanocomposite insulator. These results indicate that the dielectric and morphological properties of polymeric nanocomposite insulators are significant when considering practical applications of flexible electronics operated at low voltages.

  14. Development of integrated insulation joint for cooling pipe in tokamak reactor

    International Nuclear Information System (INIS)

    Nishio, Satoshi; Abe, Tetsuya; Kawamura, Masashi; Yamazaki, Seiichiro.

    1994-08-01

    In a tokamak fusion reactor, an electrically insulated part is needed for an in-vessel piping system in order to break an electric circuit loop. When a closed loop is formed in the piping system, large induced electromagnetic forces during a plasma disruption (rapid plasma current quench) could give damages on the piping system. Ceramic brazing joint is a conventional method for the electric circuit break, but an application to the fusion reactor is not feasible due to its brittleness. Here, a stainless steel/ceramics/stainless steel functionally gradient material (FGM) has been proposed and developed as an integrated insulation joint of the piping system. Both sides of the joint can be welded to the main pipes, and expected to be reliable even in the fusion reactor environment. When the FGM joint is manufactured by way of a sintering process, a residual thermal stress is the key issue. Through detailed computations of the residual thermal stress and several trial productions, tubular elements of FGM joints have been successfully manufactured. (author)

  15. Propagation and generation of Josephson radiation in superconductor/insulator superlattices

    International Nuclear Information System (INIS)

    Auvil, P.R.; Ketterson, J.B.

    1987-01-01

    The wave propagation and generation characteristics of a metal-insulator superlattice are calculated in a low-field Landau--Ginzburg model, including Josephson coupling through the insulating layers. It is shown that a significant increase in the phase velocity of the electromagnetic waves propagating in the superlattice occurs when the thickness of the superconducting layers becomes much less than the London penetration depth, suggesting that increased output of Josephson radiation may be achieved from such structures. Wave generation via the ac Josephson effect (in the presence of applied dc electric and magnetic fields) is studied for both parallel and series driven multilayer structures

  16. Advantages, properties and types of coatings on non-oriented electrical steels

    Energy Technology Data Exchange (ETDEWEB)

    Lindenmo, M.; Coombs, A.; Snell, D

    2000-06-02

    Electrical steels used for motor, transformer and generator applications are usually coated with an insulation coating in order to improve the performance of the material in terms of reduced power loss, punching and welding characteristics and corrosion resistance. The advantages, properties and types of insulation coatings available at European Electrical Steels are discussed in this paper.

  17. Giant magneto-optical Kerr effect and universal Faraday effect in thin-film topological insulators.

    Science.gov (United States)

    Tse, Wang-Kong; MacDonald, A H

    2010-07-30

    Topological insulators can exhibit strong magneto-electric effects when their time-reversal symmetry is broken. In this Letter we consider the magneto-optical Kerr and Faraday effects of a topological insulator thin film weakly exchange coupled to a ferromagnet. We find that its Faraday rotation has a universal value at low frequencies θF=tan(-1)α, where α is the vacuum fine structure constant, and that it has a giant Kerr rotation θK=π/2. These properties follow from a delicate interplay between thin-film cavity confinement and the surface Hall conductivity of a topological insulator's helical quasiparticles.

  18. Electrical and proximity-magnetic effects induced quantum Goos–Hänchen shift on the surface of topological insulator

    Energy Technology Data Exchange (ETDEWEB)

    Kuai, Jian [School of Physics and Electronics, Yancheng Teachers College, Yancheng, 224002 Jiangsu (China); Da, H.X., E-mail: haixia8779@163.com [Electrical and Computer Engineering Department, National University of Singapore, 4 Engineering Drive 3, 117576 (Singapore)

    2014-03-15

    We use scattering matrix method to theoretically demonstrate that the quantum Goos–Hänchen shift of the surface on three-dimensional topological insulator coated by ferromagnetic strips is sensitive to the magnitude of ferromagnetic magnetization. The dependence of quantum Goos–Hänchen shift on magnetization and gate bias is investigated by performing station phase approach. It is found that quantum Goos–Hänchen shift is positive and large under the magnetic barrier but may be positive as well as negative values under the gate bias. Furthermore, the position of quantum Goos–Hänchen peak can also be modulated by the combination of gate bias and proximity magnetic effects. Our results indicate that topological insulators are another candidates to support quantum Goos–Hänchen shift. - Highlights: • Quantum Goos–Hänchen shift of the surface on three-dimensional topological insulators is first investigated. • The magnetization affects quantum Goos–Hänchen shift of the surface on three-dimensional topological insulators. • Quantum Goos–Hänchen shift of the surface on three-dimensional topological insulators can be manipulated by the gate voltages.

  19. An investigation on rapeseed oil as potential insulating liquid

    Science.gov (United States)

    Katim, N. I. A.; Nasir, M. S. M.; Ishak, M. T.; Hamid, M. H. A.

    2018-02-01

    Insulation oils are a vital part in power transformers. Insulation oil is not only work as electrical insulation but also as a coolant inside the transformer. Due to the increasing tight regulations on the environment and safety in recent years, vegetable oils are being considered for insulation oils in power transformer. This paper presents two conditions of Rapeseed Oil (RO), which are as received (new) and dried (dry) under difference uniform field electrodes configuration (mushroom-to-mushroom and sphere-to-sphere) with gap distance at 2.5 mm as recommended by the international standards. A comparative study of AC breakdown voltage, dissipation factor (tan δ), and resistivity under variation of temperature were investigated. The experimental works were done according to the IEC 60156 and IEC 60247 standards. The results indicated that the breakdown voltages of both condition are comparable to mineral oil. The dielectric constant and resistivity of two conditions are decreased along with the increasing temperature. However, the dissipation factor properties rose up along with the temperature. The Weibull distribution was used to determine the withstand voltages at 1% and 50% for RO in two probabilities conditions.

  20. MOSFET Electric-Charge Sensor

    Science.gov (United States)

    Robinson, Paul A., Jr.

    1988-01-01

    Charged-particle probe compact and consumes little power. Proposed modification enables metal oxide/semiconductor field-effect transistor (MOSFET) to act as detector of static electric charges or energetic charged particles. Thickened gate insulation acts as control structure. During measurements metal gate allowed to "float" to potential of charge accumulated in insulation. Stack of modified MOSFET'S constitutes detector of energetic charged particles. Each gate "floats" to potential induced by charged-particle beam penetrating its layer.

  1. Cellulose Insulation

    Science.gov (United States)

    1980-01-01

    Fire retardant cellulose insulation is produced by shredding old newspapers and treating them with a combination of chemicals. Insulating material is blown into walls and attics to form a fiber layer which blocks the flow of air. All-Weather Insulation's founders asked NASA/UK-TAP to help. They wanted to know what chemicals added to newspaper would produce an insulating material capable of meeting federal specifications. TAP researched the query and furnished extensive information. The information contributed to successful development of the product and helped launch a small business enterprise which is now growing rapidly.

  2. Electricity remains a serious workplace hazard.

    Science.gov (United States)

    Proctor, Laura; Kuchibotla, Srin

    2013-08-01

    Anyone who works in an industrial environment or is employed in the utility, mass transit, industrial goods manufacturing, or telecommunications industry - as well as many others - may be at risk for electrocution. Electric shock costs workers' lives and results in painful and debilitating injuries every year. Lockout/tagout procedures protect against electrocution, as do rubber insulating gloves, which must be worn any time workers are exposed to energized parts operating at 50 volts or higher. Some newer styles of rubber insulating gloves not only protect against electric shock, but also offer the dexterity and flexibility workers need for hours of comfortable wear.

  3. A study on the barrier effect with respect to the condition of solid insulation materials in GN{sub 2}

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Hong Seok; Mo, Young Kyu; Lee, On You; Kim, Jun Il; Bang, Seung Min; Kang, Jong O; Kang, Hyoung Ku [Dept. of Electrical Engineering, Korea National University of Transportation, Chungju (Korea, Republic of); Nam, Seo Ho [Dept. of Electrical and Electronic Engineering, Applied Superconductivity Lab., Yonsei University, Seoul (Korea, Republic of)

    2015-03-15

    High voltage superconducting apparatuses have been developed presently around the world under AC and DC sources. In order to improve electrical reliability of superconducting apparatuses with AC and DC networks, a study on the DC as well as the AC electrical breakdown characteristics of cryogenic insulations should be conducted for developing a high voltage superconducting apparatus. Recently, a sub-cooled liquid nitrogen cooling system is known to be promising method for developing a high voltage superconducting apparatus. A sub-cooled liquid nitrogen cooling system uses gaseous nitrogen to control the pressure and enhance the dielectric characteristics. However, the dielectric characteristics of gaseous nitrogen are not enough to satisfy the grade of insulation for a high voltage superconducting apparatus. In this case, the application of solid insulating barriers is regarded as an effective method to reinforce the dielectric characteristics of a high voltage superconducting apparatus. In this paper, it is dealt with a barrier effect on the DC and AC dielectric characteristics of gaseous nitrogen with respect to the position and number of solid insulating barriers. As results, the DC and AC electrical breakdown characteristics by various barrier effects is verified.

  4. Effect that radiation exerts to insulation breakdown of heat resistant polymer materials

    International Nuclear Information System (INIS)

    Fujita, Shigetaka; Baba, Makoto; Noto, Fumitoshi; Ruike, Mitsuo.

    1990-01-01

    Artificial satellites are always exposed to cosmic rays which contain the radiations which do not reach the ground, therefore, the radiation resistance of the polymer insulators for cables and others used in such environment becomes a problem. Also the polymer insulator materials used for nuclear facilities require excellent radiation resistance. It is important to examine the effect that radiation exerts to electric insulation characteristics from the viewpoint of material development. In this paper, the insulation breakdown characteristics of heat resistant polymer films and the mini-cables made for trial of heat resistant polymer materials in the case without irradiation and in the case of gamma ray irradiation, and the results of the structural analysis are reported. The specimens tested, the experimental method and the results are described. The insulation breakdown strength of PFA and FEP films lowered from 0.15-0.2 MGy, but that of PEEK film did not change up to 5 MGy. It was found that fluorine group resins were apt to deteriorate by oxidation as dose increased. (K.I.)

  5. Investigation of wear of insulation of traction engines of locomotives in operation

    Directory of Open Access Journals (Sweden)

    Nefedov Roman

    2018-01-01

    Full Text Available The article analyzes reliability of traction electric motors in operation. It is shown that the greatest number of failure falls on the winding of the armature. Investigation of the causes of increased wear of the armature winding insulation was carried out using the dynamic thermal model of the electric motor. The model is represented by 150 final elements and takes into account the conditions of thermal conductivity between the nodes and heat transfer to the cooling air. Verification of the model was carried out by comparison with the results of thermal tests of electric motors of the series HБ-406 and ЭД-118. The field of temperatures in the traction motor under various loads was investigated. It is shown that in stationary mode the temperature change along the armature winding can reach 60C. Modeling of thermal dynamic processes in the engine during its operation on the locomotive allowed to identify the most stressed nodes. It is shown that the resource of the electric motor is determined by the wear of the insulation of the frontal part of the armature winding on the side of the traction drive of the locomotive.

  6. Accelerated thermal and radiation-oxidation combined degradation of electric cable insulation materials

    International Nuclear Information System (INIS)

    Yagi, Toshiaki; Seguchi, Tadao; Yoshida, Kenzo

    1986-03-01

    For the development of accelerated testing methodology to estimate the life time of electric cable, which is installed in radiation field such as a nuclear reactor containment vessel, radiation and thermal combined degradation of cable insulation and jacketing materials was studied. The materials were two types of formulated polyethylene, ethylene-propylene rubber, Hypalon, and Neoprene. With Co-60 γ-rays the materials were irradiated up to 0.5 MGy under vacuum and in oxygen under pressure, then exposed to thermal aging at elevated temperature in oxygen. The degradation was investigated by the tensile test, gelfraction, and swelling measurements. The thermal degradation rate for each sample increases with increase of oxygen concentration, i.e. oxygen pressure, during the aging, and tends to saturate above 0.2 MPa of oxygen pressure. Then, the effects of irradiation and the temperature on the thermal degradation rate were investigated at the oxygen pressure of 0.2 MPa in the temperature range from 110 deg C to 150 deg C. For all of samples irradiated in oxygen, the following thermal degradation rate was accelerated by several times comparing with unirradiated samples, while the rate of thermal degradation for the sample except Neoprene irradiated under vacuum was nearly equal to that of unirradiated one. By the analysis of thermal degradation rate against temperature using Arrhenius equation, it was found that the activation energy tends to decrease for the samples irradiated in oxidation condition. (author)

  7. Insulating fcc YH

    International Nuclear Information System (INIS)

    Molen, S. J. van der; Nagengast, D. G.; Gogh, A. T. M. van; Kalkman, J.; Kooij, E. S.; Rector, J. H.; Griessen, R.

    2001-01-01

    We study the structural, optical, and electrical properties of Mg z Y 1-z switchable mirrors upon hydrogenation. It is found that the alloys disproportionate into essentially pure YH 3-δ and MgH 2 with the crystal structure of YH 3-δ dependent on the Mg concentration z. For 0 3-δ are observed, whereas for z≥0.1 only cubic YH 3-δ is present. Interestingly, cubic YH 3-δ is expanded compared to YH 2 , in disagreement with theoretical predictions. From optical and electrical measurements we conclude that cubic YH 3-δ is a transparent insulator with properties similar to hexagonal YH 3-δ . Our results are inconsistent with calculations predicting fcc YH 3-δ to be metallic, but they are in good agreement with recent GW calculations on both hcp and fcc YH 3 . Finally, we find an increase in the effective band gap of the hydrided Mg z Y 1-z alloys with increasing z. Possibly this is due to quantum confinement effects in the small YH 3 clusters

  8. Experimental charge fractions of hydrogen scattered from insulators at 50-340 keV

    CERN Document Server

    Ross, Graham G

    2002-01-01

    Ion bombardment of insulators induces accumulation of electric charges at and under the insulator surfaces. This paper deals with the effect of the accumulated electric charges on the charge fractions of scattered hydrogen. We have measured and compiled charge fractions of hydrogen, in the energy range (for the scattered particles) from 50 to 340 keV, scattered from polystyrene, polymethylmethacrylate, polycarbonate, polyethylene and silicon. In order to establish the effect of the charge accumulation, some samples have been cut from a thick (1 mm) sheet, while some others have been spin coated (approx 250 nm) onto silicon wafers. Experimental measurements have been fitted with the equation f(0)=Aexp(-V sup 2 /V sub i V sub 0), where f(0) is the neutral fraction, V the velocity, V sub i the 'Bohr velocity' for the electron of projectiles, A and V sub 0 the fitting parameters. Comparisons using the least-square fitting procedure have shown that the accumulation of electric charges on the thick polymer samples ...

  9. A privacy-preserving sharing method of electricity usage using self-organizing map

    Directory of Open Access Journals (Sweden)

    Yuichi Nakamura

    2018-03-01

    Full Text Available Smart meters for measuring electricity usage are expected in electricity usage management. Although the relevant power supplier stores the measured data, the data are worth sharing among power suppliers because the entire data of a city will be required to control the regional grid stability or demand–supply balance. Even though many techniques and methods of privacy-preserving data mining have been studied to share data while preserving data privacy, a study on sharing electricity usage data is still lacking. In this paper, we propose a sharing method of electricity usage while preserving data privacy using a self-organizing map. Keywords: Privacy preserving, Data sharing, Self-Organizing map

  10. Realization of the Axion Insulator State in Quantum Anomalous Hall Sandwich Heterostructures

    Science.gov (United States)

    Xiao, Di; Jiang, Jue; Shin, Jae-Ho; Wang, Wenbo; Wang, Fei; Zhao, Yi-Fan; Liu, Chaoxing; Wu, Weida; Chan, Moses H. W.; Samarth, Nitin; Chang, Cui-Zu

    2018-02-01

    The "magnetoelectric effect" arises from the coupling between magnetic and electric properties in materials. The Z2 invariant of topological insulators (TIs) leads to a quantized version of this phenomenon, known as the topological magnetoelectric (TME) effect. This effect can be realized in a new topological phase called an "axion insulator" whose surface states are all gapped but the interior still obeys time reversal symmetry. We demonstrate such a phase using electrical transport measurements in a quantum anomalous Hall (QAH) sandwich heterostructure, in which two compositionally different magnetic TI layers are separated by an undoped TI layer. Magnetic force microscopy images of the same sample reveal sequential magnetization reversals of the top and bottom layers at different coercive fields, a consequence of the weak interlayer exchange coupling due to the spacer. When the magnetization is antiparallel, both the Hall resistance and Hall conductance show zero plateaus, accompanied by a large longitudinal resistance and vanishing longitudinal conductance, indicating the realization of an axion insulator state. Our findings thus show evidence for a phase of matter distinct from the established QAH state and provide a promising platform for the realization of the TME effect.

  11. 29 CFR 1915.132 - Portable electric tools.

    Science.gov (United States)

    2010-07-01

    ... 29 Labor 7 2010-07-01 2010-07-01 false Portable electric tools. 1915.132 Section 1915.132 Labor... § 1915.132 Portable electric tools. The provisions of this section shall apply to ship repairing... frames of portable electric tools and appliances, except double insulated tools approved by Underwriters...

  12. Semiconducting:insulating polymer blends for optoelectronic applications—a review of recent advances

    KAUST Repository

    Scaccabarozzi, A. D.; Stingelin, N.

    2014-01-01

    In recent years, immense efforts in the organic electronics field have led to unprecedented progress and to devices of ever increasing performance. Despite these advances, new opportunities are sought in order to widen the applications of organic-based technologies and expand their functionalities and features. For this purpose, use of multicomponent systems seems an interesting approach in view of, e.g., increasing the mechanical flexibility and stability of organic electronic products as well as introducing other features such as self-encapsulation. One specific strategy is based on blending polymeric insulators with organic semiconductors; which has led to a desired improvement of the mechanical properties of organic devices, producing in certain scenarios robust and stable architectures. Here we discuss the working principle of semiconductor:insulator blends, examining the different approaches that have recently been reported in literature. We illustrate how organic field-effect transistors (OFET)s and organic solar cells (OPV)s can be fabricated with such systems without detrimental effects on the resulting device characteristics even at high contents of the insulator. Furthermore, we review the various properties that can be enhanced and/or manipulated by blending including air stability, mechanical toughness, H- vs. J-aggregation, etc. This journal is © the Partner Organisations 2014.

  13. Insulation system in an integrated motor compressor

    Energy Technology Data Exchange (ETDEWEB)

    Sihvo, V.

    2010-07-01

    A high-speed and high-voltage solid-rotor induction machine provides beneficial features for natural gas compressor technology. The mechanical robustness of the machine enables its use in an integrated motor-compressor. The technology uses a centrifugal compressor, which is mounted on the same shaft with the high-speed electrical machine driving it. No gearbox is needed as the speed is determined by the frequency converter. The cooling is provided by the process gas, which flows through the motor and is capable of transferring the heat away from the motor. The technology has been used in the compressors in the natural gas supply chain in the central Europe. New areas of application include natural gas compressors working at the wellheads of the subsea gas reservoir. A key challenge for the design of such a motor is the resistance of the stator insulation to the raw natural gas from the well. The gas contains water and heavy hydrocarbon compounds and it is far harsher than the sales gas in the natural gas supply network. The objective of this doctoral thesis is to discuss the resistance of the insulation to the raw natural gas and the phenomena degrading the insulation. The presence of partial discharges is analyzed in this doctoral dissertation. The breakdown voltage of the gas is measured as a function of pressure and gap distance. The partial discharge activity is measured on small samples representing the windings of the machine. The electrical field behavior is also modeled by finite element methods. Based on the measurements it has been concluded that the discharges are expected to disappear at gas pressures above 4 - 5 bar. The disappearance of discharges is caused by the breakdown strength of the gas, which increases as the pressure increases. Based on the finite element analysis, the physical length of a discharge seen in the PD measurements at atmospheric pressure was approximated to be 40 - 120 mum. The chemical aging of the insulation when exposed to raw

  14. Neotropical electric fishes (Gymnotiformes as model organisms for bioassays

    Directory of Open Access Journals (Sweden)

    Milena Ferreira

    2015-04-01

    Full Text Available Electric fishes (Gymnotiformes inhabit Central and South America and form a relatively large group with more than 200 species. Besides a taxonomic challenge due to their still unresolved systematic, wide distribution and the variety of habitats they occupy, these fishes have been intensively studied due to their peculiar use of bioelectricity for electrolocation and communication. Conventional analysis of cells, tissues and organs have been complemented with the studies on the electric organ discharges of these fishes. This review compiles the results of 13 bioassays developed during the last 50 years, which used the quickness, low costs and functionality of the bioelectric data collection of Gymnotiformes to evaluate the effects of environmental contaminants and neuroactive drugs.

  15. Electricity sequence control

    International Nuclear Information System (INIS)

    Shin, Heung Ryeol

    2010-03-01

    The contents of the book are introduction of control system, like classification and control signal, introduction of electricity power switch, such as push-button and detection switch sensor for induction type and capacitance type machinery for control, solenoid valve, expression of sequence and type of electricity circuit about using diagram, time chart, marking and term, logic circuit like Yes, No, and, or and equivalence logic, basic electricity circuit, electricity sequence control, added condition, special program control about choice and jump of program, motor control, extra circuit on repeat circuit, pause circuit in a conveyer, safety regulations and rule about classification of electricity disaster and protective device for insulation.

  16. Material-controlled dynamic vacuum insulation

    Science.gov (United States)

    Benson, D.K.; Potter, T.F.

    1996-10-08

    A compact vacuum insulation panel is described comprising a chamber enclosed by two sheets of metal, glass-like spaces disposed in the chamber between the sidewalls, and a high-grade vacuum in the chamber includes apparatus and methods for enabling and disabling, or turning ``on`` and ``off`` the thermal insulating capability of the panel. One type of enabling and disabling apparatus and method includes a metal hydride for releasing hydrogen gas into the chamber in response to heat, and a hydrogen grate between the metal hydride and the chamber for selectively preventing and allowing return of the hydrogen gas to the metal hydride. Another type of enabling and disabling apparatus and method includes a variable emissivity coating on the sheets of metal in which the emissivity is controllably variable by heat or electricity. Still another type of enabling and disabling apparatus and method includes metal-to-metal contact devices that can be actuated to establish or break metal-to-metal heat paths or thermal short circuits between the metal sidewalls. 25 figs.

  17. Variably insulating portable heater/cooler

    Science.gov (United States)

    Potter, T.F.

    1998-09-29

    A compact vacuum insulation panel is described comprising a chamber enclosed by two sheets of metal, glass-like spaces disposed in the chamber between the sidewalls, and a high-grade vacuum in the chamber includes apparatus and methods for enabling and disabling, or turning ``on`` and ``off`` the thermal insulating capability of the panel. One type of enabling and disabling apparatus and method includes a metal hydride for releasing hydrogen gas into the chamber in response to heat, and a hydrogen grate between the metal hydride and the chamber for selectively preventing and allowing return of the hydrogen gas to the metal hydride. Another type of enabling and disabling apparatus and method includes a variable emissivity coating on the sheets of metal in which the emissivity is controllably variable by heat or electricity. Still another type of enabling and disabling apparatus and method includes metal-to-metal contact devices that can be actuated to establish or break metal-to-metal heat paths or thermal short circuits between the metal sidewalls. 25 figs.

  18. Radiation-controlled dynamic vacuum insulation

    Science.gov (United States)

    Benson, D.K.; Potter, T.F.

    1995-07-18

    A compact vacuum insulation panel is described comprising a chamber enclosed by two sheets of metal, glass-like spaces disposed in the chamber between the sidewalls, and a high-grade vacuum in the chamber that includes apparatus and methods for enabling and disabling, or turning ``on`` and ``off`` the thermal insulating capability of the panel. One type of enabling and disabling apparatus and method includes a metal hydride for releasing hydrogen gas into the chamber in response to heat, and a hydrogen grate between the metal hydride and the chamber for selectively preventing and allowing return of the hydrogen gas to the metal hydride. Another type of enabling and disabling apparatus and method includes a variable emissivity coating on the sheets of metal in which the emissivity is controllably variable by heat or electricity. Still another type of enabling and disabling apparatus and method includes metal-to-metal contact devices that can be actuated to establish or break metal-to-metal heat paths or thermal short circuits between the metal sidewalls. 25 figs.

  19. THERMO-ELECTRIC GENERATOR

    Science.gov (United States)

    Jordan, K.C.

    1958-07-22

    The conversion of heat energy into electrical energy by a small compact device is descrtbed. Where the heat energy is supplied by a radioactive material and thermopIIes convert the heat to electrical energy. The particular battery construction includes two insulating discs with conductive rods disposed between them to form a circular cage. In the center of the cage is disposed a cup in which the sealed radioactive source is located. Each thermopile is formed by connecting wires from two adjacent rods to a potnt on an annular ring fastened to the outside of the cup, the ring having insulation on its surface to prevent electrica1 contact with the thermopiles. One advantage of this battery construction is that the radioactive source may be inserted after the device is fabricated, reducing the radiation hazard to personnel assembling the battery.

  20. Risk Assessment of Failure of Outdoor High Voltage Polluted Insulators under Combined Stresses Near Shoreline

    Directory of Open Access Journals (Sweden)

    Muhammad Majid Hussain

    2017-10-01

    Full Text Available The aim of this paper is to investigate the various effects of climate conditions on outdoor insulators in coastal areas as a result of saline contamination under acidic and normal cold fog, determining significant electrical and physico-chemical changes on the insulator surface and considering the effect of discharge current, electric field distribution and surface roughness. To replicate similar conditions near the shoreline, experimental investigations have been carried out on insulation materials with the combined application of saline contamination and acidic or normal cold fog. The test samples included silicone rubber (SiR, ethylene propylene diene monomer (EPDM and high-density polyethylene (HDPE, which were used as reference. The materials are of the same composition as those used in real-life outdoor high voltage insulators. All samples were aged separately in an environmental chamber for 150 h for various saline contaminations combined with acidic and normal cold fog, and were generated by means of the adopted experimental setup. This analysis represented conditions similar to those existing near the shoreline exposed to saline and acid spray during winter and early spring. Electric field and discharge current along polymeric samples were examined under acidic and normal cold fog. Fourier transform infrared (FTIR spectroscopy and scanning electron microscopic (SEM were used to probe the physico-chemical changes on the samples surface and investigate the hydrophobicity recovery property after aging tests. Finally, a comparative study was carried out on polymeric samples before and after being exposed to the acidic and normal cold fog based on the results obtained from the experiment. Research data may provide references for the better prediction of surface degradation as well as for the better material coating and design of external insulation.

  1. Electrical characteristics of a small plasma focus device

    International Nuclear Information System (INIS)

    Choi, P.; Favre, M.; Silva, P.; Chuaqui, H.; Wyndham, E.

    1996-01-01

    Efficient plasma focus operation relies on uniform initial breakdown across the insulator surface. The basic plasma focus electric circuit is discussed in order to highlight circuit modifications that produce high voltage oscillation at the initial breakdown time. Superimposed on the main discharge voltage, such oscillating voltage has been found in real systems to enhance the initial gas breakdown by localizing the initial current path across the insulator surface. PSPICE circuit simulations are compared with electric signals from different operational plasma focus devices. (author). 3 figs., 7 refs

  2. Improvement of Surface Flashover Performance of Al2O3 Ceramics in Vacuum by Adopting A-B-A Insulation System

    International Nuclear Information System (INIS)

    Li Shengtao; Zhang Tuo; Huang Qifeng; Li Weiwei; Ni Fengyan; Li Jianying

    2011-01-01

    A new insulation system with inorganic A-B-A insulators was proposed to improve the surface flashover performance in vacuum. Inorganic A-B-A insulator samples of Mo/Al 2 O 3 cermet-Al 2 O 3 ceramic-Mo/Al 2 O 3 cermet were prepared, in which the conductivity and permittivity of the Mo/Al 2 O 3 cermets were controlled through different amount of metallic molybdenum powder added. The effects of both conductivity and permittivity of Mo/Al 2 O 3 cermets on the DC and impulse surface flashover voltage in vacuum were experimentally investigated. The result showed that the DC and impulse surface flashover voltage were improved by 52% and 95%, respectively. For the distribution of electric field, two triple junctions, i.e., vacuum-layer A-cathode (TJ1) and vacuum-layer A-layer B (TJ2) were prepared with the introduction of layer A into the A-B-A insulation system. Based on the electric field distribution obtained via electrostatic field simulation and Maxwell-Wagner three-layer model, the electric field of TJ1 decreases while that of TJ2 increases with the increase in conductivity and permittivity of layer A under applied DC and impulse voltage, respectively. Therefore, the improvement of surface flashover performance of A-B-A insulators has been reasonably explained. (fusion engineering)

  3. The latest electrical installation (I)

    International Nuclear Information System (INIS)

    Won, Jong Su

    1976-04-01

    This book deals with the latest electrical installation. The contents of this book are construction electrical installation, regulations related electrical installation, foundation and principle of wiring, main line feeder, lighting installation, power of wiring, main line feeder, lighting installation, power installation, method to read structure drawing for electrical construct drawing electric lamp wiring diagram, working drawing, material and tools and method of construction of electrical installation on types of wiring construction, metallic conduit, rigid poly-vinyl conduit wiring, bus duct work, cable work and insulation out of metal lathed.

  4. Electric power generator

    International Nuclear Information System (INIS)

    Carney, H.C.

    1977-01-01

    An electric power generator of the type employing a nuclear heat source and a thermoelectric converter is described wherein a transparent thermal insulating medium is provided inside an encapsulating enclosure to thermally insulate the heat source and thermoelectric generator. The heat source, the thermoelectric converter, and the enclosure are provided with facing surfaces which are heat-reflective to a substantial degree to inhibit radiation of heat through the medium of the encapsulating enclosure. Multiple reflective foils may be spaced within the medium as necessary to inhibit natural convection of heat and/or further inhibit radiation

  5. Thermal insulation

    International Nuclear Information System (INIS)

    Aspden, G.J.; Howard, R.S.

    1988-01-01

    The patent concerns high temperature thermal insulation of large vessels, such as the primary vessel of a liquid metal cooled nuclear reactor. The thermal insulation consists of multilayered thermal insulation modules, and each module comprises a number of metal sheet layers sandwiched between a back and front plate. The layers are linked together by straps and clips to control the thickness of the module. (U.K.)

  6. Semi-insulating GaAs detectors of fast neutrons

    International Nuclear Information System (INIS)

    Sagatova, A.; Sedlackova, K.; Necas, V.; Zatko, B.; Dubecky, F.; Bohacek, P.

    2012-01-01

    The present work deals with the technology of HDPE neutron conversion layer application on the surface of semi-insulating (SI) GaAs detectors via developed polypropylene (PP) based glue. The influence of glue deposition on the electric properties of the detectors was studied as well as the ability of the detectors to register the fast neutrons from "2"3"9Pu-Be neutron source. (authors)

  7. 14 CFR 23.1359 - Electrical system fire protection.

    Science.gov (United States)

    2010-01-01

    ... procedures must be fire-resistant. (c) Insulation on electrical wire and electrical cable must be self... this part, or other approved equivalent methods. The average burn length must not exceed 3 inches (76...

  8. 75 FR 4310 - Credit Reforms in Organized Wholesale Electric Markets

    Science.gov (United States)

    2010-01-27

    ... energy markets, in which regional transmission organizations (RTOs) and independent system operators... require RTOs and ISOs to adopt tariff revisions reflecting these proposed credit reforms. The Commission... is in the organized wholesale electric markets.\\5\\ Individual RTOs and ISOs developed their own...

  9. Assessment of the risk of failure of high voltage substations due to environmental conditions and pollution on insulators.

    Science.gov (United States)

    Castillo Sierra, Rafael; Oviedo-Trespalacios, Oscar; Candelo, John E; Soto, Jose D

    2015-07-01

    Pollution on electrical insulators is one of the greatest causes of failure of substations subjected to high levels of salinity and environmental pollution. Considering leakage current as the main indicator of pollution on insulators, this paper focuses on establishing the effect of the environmental conditions on the risk of failure due to pollution on insulators and determining the significant change in the magnitude of the pollution on the insulators during dry and humid periods. Hierarchical segmentation analysis was used to establish the effect of environmental conditions on the risk of failure due to pollution on insulators. The Kruskal-Wallis test was utilized to determine the significant changes in the magnitude of the pollution due to climate periods. An important result was the discovery that leakage current was more common on insulators during dry periods than humid ones. There was also a higher risk of failure due to pollution during dry periods. During the humid period, various temperatures and wind directions produced a small change in the risk of failure. As a technical result, operators of electrical substations can now identify the cause of an increase in risk of failure due to pollution in the area. The research provides a contribution towards the behaviour of the leakage current under conditions similar to those of the Colombian Caribbean coast and how they affect the risk of failure of the substation due to pollution.

  10. 18 CFR 39.10 - Changes to an Electric Reliability Organization Rule or Regional Entity Rule.

    Science.gov (United States)

    2010-04-01

    ... RULES CONCERNING CERTIFICATION OF THE ELECTRIC RELIABILITY ORGANIZATION; AND PROCEDURES FOR THE ESTABLISHMENT, APPROVAL, AND ENFORCEMENT OF ELECTRIC RELIABILITY STANDARDS § 39.10 Changes to an Electric... Reliability Organization Rule or Regional Entity Rule. 39.10 Section 39.10 Conservation of Power and Water...

  11. Metal-insulator transition in vanadium dioxide

    International Nuclear Information System (INIS)

    Zylbersztejn, A.; Mott, N.F.

    1975-01-01

    The basic physical parameters which govern the metal-insulator transition in vanadium dioxide are determined through a review of the properties of this material. The major importance of the Hubbard intra-atomic correlation energy in determining the insulating phase, which was already evidence by studies of the magnetic properties of V 1 -/subx/Cr/subx/O 2 alloys, is further demonstrated from an analysis of their electrical properties. An analysis of the magnetic susceptibility of niobium-doped VO 2 yields a picture for the current carrier in the low-temperature phase in which it is accompanied by a spin cloud (owing to Hund's-rule coupling), and has therefore an enhanced mass (m approx. = 60m 0 ). Semiconducting vanadium dioxide turns out to be a borderline case for a classical band-transport description; in the alloys at high doping levels, Anderson localization with hopping transport can take place. Whereas it is shown that the insulating phase cannot be described correctly without taking into account the Hubbard correlation energy, we find that the properties of the metallic phase are mainly determined by the band structure. Metallic VO 2 is, in our view, similar to transition metals like Pt or Pd: electrons in a comparatively wide band screening out the interaction between the electrons in a narrow overlapping band. The magnetic susceptibility is described as exchange enhanced. The large density of states at the Fermi level yields a substantial contribution of the entropy of the metallic electrons to the latent heat. The crystalline distortion removes the band degeneracy so that the correlation energy becomes comparable with the band width and a metal-insulator transition takes place

  12. Effects of radiation on insulation materials

    International Nuclear Information System (INIS)

    Poehlchen, R.

    1992-01-01

    This presentation will concentrate on the insulation materials which are suitable for the insulation of superconducting magnets for fusion. For the next generation of fusion machines with magnetic confinement as NET and ITER general agreement exists that the insulation will consist of fibre reinforced organic matrix material, a composite. Much effort has been put into the investigation of the radiation resistance of such materials during the last 20-30 years, see in particular the numerous reports of accelerator laboratories on this subject. But very few of the published data are relevant for the superconducting magnets of fusion machines. Either the irradiation and testing was carried out at RT or LN 2 temperature and/or the irradiation spectrum was not representative for a fusion machine and/or the materials investigated are not applicable for the insulation of S.C. fusion magnets. Therefore test programs have been launched recently, one by the NET team. The intention of the first chapter is to give guidance on the choice of materials which are suitable as insulation materials from a more general point of view. A good understanding of the coil manufacturing process is needed for this purpose. The second chapter explains the irradiation spectrum seen by the magnets. A third chapter does present the NET/ITER test programme. Step 1 was completed at the end of 1989, the second step will be carried out in the autumn of 1991. Finally, a general assessment of materials and testing methods will be given with recommendations for further testing

  13. Electric breakdown of high polymer insulating materials at cryogenic temperature

    International Nuclear Information System (INIS)

    Kim, Sanhyon; Yoshino, Katsumi

    1985-01-01

    Cryogenic properties : temperature dependence of E sub(b) and effects of media upon E sub(b) were investigated on several high polymers. Temperature conditions were provided by liquid He (4.2 K), liquid N 2 (77 K) and cryogen (dry ice-methyl alcohol, 194 K). Silicone oil was used also at ambient temperature and elevated temperature. Polymer film coated with gold by vacuum evaporation was placed in cryostat, and high tension from pulse generator was applied to the film. Dielectric breakdowns were detected by oscilloscope and observed visually. The results of experiment are summerized as follow. (1) E sub(b) of film in He is affected by medium remarkably, and covering with 3-methyl pentane is effective for increasing E sub(b). (2) Temperature dependence of E sub(b) was not recognized in cryogenic temperature below liquid N 2 . (3) Temperature characteristic of E sub(b) changes considerably at the critical temperature T sub(c), and T sub(c) is dependent on material. (4) Strength against dielectric breakdown under cryogenic temperature is not affected by bridging caused by irradiation of electron beam. (5) Dielectric breakdown is thought to be caused by electronic process such as electron avalanche. Consequently, for designing insulation for the temperature below liquid He, insulation design for liquid N 2 is thought to be sufficient. However, the degradation and breakdown by mechanical stress under cryogenic temperature must be taken into consideration. (Ishimitsu, A.)

  14. Determination of optimum insulation thicknesses using economical analyse for exterior walls of buildings with different masses

    Directory of Open Access Journals (Sweden)

    Okan Kon

    2017-07-01

    Full Text Available In this study, five different cities were selected from the five climatic zones according to Turkish standard TS 825, and insulation thicknesses of exterior walls of sample buildings were calculated by using optimization. Vertical perforated bricks with density of 550 kg/m3 and 1000 kg/m3 were chosen within the study content. Glass wool, expanded polystyrene (XPS, extruded polystyrene (EPS were considered as insulation materials. Additionally, natural gas, coal, fuel oil and LPG were utilized as fuel for heating process while electricity was used for cooling.  Life cycle cost (LCC analysis and degree-day method were the approaches for optimum insulation thickness calculations. As a result, in case of usage vertical perforated bricks with density of 550 kg/m3 and 1000 kg/m3 resulted different values in between 0.005-0.007 m (5-7 mm in the optimum insulation thickness calculations under different insulation materials.  Minimum optimum insulation thickness was calculated in case XPS was preferred as insulation material, and the maximum one was calculated in case of using glass wool.

  15. The Future of Centrally-Organized Wholesale Electricity Markets

    Energy Technology Data Exchange (ETDEWEB)

    Glazer, Craig [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Morrison, Jay [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Breakman, Paul [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Clements, Allison [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Schwartz, Lisa [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)

    2017-06-21

    The electricity grid in the United States is organized around a network of large, centralized power plants and high voltage transmission lines that transport electricity, sometimes over large distances, before it is delivered to the customer through a local distribution grid. This network of centralized generation and high voltage transmission lines is called the “bulk power system.” Costs relating to bulk power generation typically account for more than half of a customer’s electric bill.1 For this reason, the structure and functioning of wholesale electricity markets have major impacts on costs and economic value for consumers, as well as energy security and national security. Diverse arrangements for bulk power wholesale markets have evolved over the last several decades. The Southeast and Western United States outside of California have a “bilateral-based” bulk power system where market participants enter into long-term bilateral agreements — using competitive procurements through power marketers, direct arrangements among utilities or with other generation owners, and auctions and exchanges.

  16. Simulation of a two-dimensional sheath over a flat insulator-conductor interface on a radio-frequency biased electrode in a high-density plasma

    International Nuclear Information System (INIS)

    Kim, Doosik; Economou, Demetre J.

    2004-01-01

    A combined fluid/Monte Carlo (MC) simulation was developed to study the two-dimensional (2D) sheath over a flat insulator/conductor interface on a radio-frequency (rf) biased electrode in a high-density plasma. The insulator capacitance increased the local impedance between the plasma and the bias voltage source. Thus, for uniform ion density and electron temperature far away from the wall, the sheath potential over the insulator was only a fraction of that over the conductor, resulting in a thinner sheath over the insulator. The fluid model provided the spatiotemporal profiles of the 2D sheath electric field. These were used as input to the MC simulation to compute the ion energy distribution (IED) and ion angular distribution (IAD) at different locations on the surface. The ion flux, IED, and IAD changed drastically across the insulator/conductor interface due to the diverging rf electric field in the distorted sheath. The ion flux was larger on the conductor at the expense of that on the insulator. Both the ion impact angle and angular spread increased progressively as the material interface was approached. The ion impact energy and energy spread were smaller on the insulator as compared to the conductor. For given plasma parameters, as the insulator thickness was increased, the sheath potential and thickness over the insulator decreased, and sheath distortion became more pronounced

  17. Comparative Investigation of Pollution Accumulation and Natural Cleaning for Different HV Insulators

    Directory of Open Access Journals (Sweden)

    M. Dimitropoulou

    2015-04-01

    Full Text Available High Voltage insulators are scattered throughout any HV network and a single insulator fault may cause an excessive outage. Reliability is a key issue for electric power systems and fault-free performance of insulators greatly reflects on the reliability of the system. Environmental influence is rather important for the optimum selection of outdoor insulators and, therefore, field measurements provide valuable information. Utilities perform such measurements in order to decide upon the location/route of new HV installations (substations, lines etc and also to optimize the selection, maintenance and replacement of already installed insulators. A rather interesting case in Greek territory is the island of Crete, due to the coastal development of the network and the local weather conditions. The Greek utility has employed a variety of remedies to cope with the pollution problem. Following the positive feedback after the installation on certain tower in the past, a large project to replace all ceramic insulators with new polymer ones of hydrophobic surface is now in progress. Polymer coatings have also been extensively applied on substations and also on certain areas/towers of the transmission network in the past. In order to investigate the pollution accumulation and the impact of natural washing on different insulator types, a series of periodical ESDD and NSDD pollution measurements were conducted in HEDNO’s TALOS High Voltage Test Station for a 3-months period. Multiple measurements were performed on each insulator every month in order to collect additional data. Five different insulators were selected based on the types historically used in the Cretan Network. Along with the standard glass disc profile, two strings of glass fog profile (the one coated with RTV and two long-rod composite insulators of different shed profile and material were used. Results are presented and discussed in this paper.

  18. A non-commutative formula for the isotropic magneto-electric response

    International Nuclear Information System (INIS)

    Leung, Bryan; Prodan, Emil

    2013-01-01

    A non-commutative formula for the isotropic magneto-electric response of disordered insulators under magnetic fields is derived using the methods of non-commutative geometry. Our result follows from an explicit evaluation of the Ito derivative with respect to the magnetic field of the non-commutative formula for the electric polarization reported in Schulz-Baldes and Teufel (2012 arXiv:1201.4812v1). The quantization, topological invariance and connection to a second Chern number of the magneto-electric response are discussed in the context of three-dimensional, disordered, time-reversal or inversion symmetric topological insulators. (paper)

  19. Development of radiation resistant PEEK insulation cable

    International Nuclear Information System (INIS)

    Mio, Keigo; Ogiwara, Norio; Hikichi, Yusuke; Furukori, Hisayoshi; Arai, Hideyuki; Nishizawa, Daiji; Nishidono, Toshiro

    2009-04-01

    Material characterization and development has been carried out for cable insulation suitable for use in the J-PARC 3-GeV RCS radiation environment. In spite of its high cost, PEEK (polyether-ether-ketone) has emerged as the leading candidate satisfying requirements of being non-halogen based, highly incombustible and with radiation resistant at least 10 MGy, along with the usual mechanical characteristics such as good elongation at break, which are needed in a cable insulation. Gamma-ray irradiation tests have been done in order to study radiation resistance of PEEK cable. Further, mechanical, electrical and fire retardant characteristics of a complete cable such as would be used at the J-PARC RCS were investigated. As a result, PEEK cables were shown to be not degraded by radiation up to at least 10 MGy, and thus could be expected to operate stably under the 3-GeV RCS radiation environment. (author)

  20. Impact of defects on electrical connectivity of monolayer of ideally aligned rods

    International Nuclear Information System (INIS)

    Tarasevich, Yu Yu; Dubinin, D O; Laptev, V V; Lebovka, N I

    2016-01-01

    The processes of formation of electrically conductive films filled by aligned elongated nanoparticles, i.e. nanotubes, nanowires or fibers attract great attention in nanotecnological applications. The alignment can be controlled by external electric fields, evaporation-driven self-assembly and assisted by different other techniques. This work studies the impact of defects on electrical connectivity of ideally aligned monolayer of rods (k-mers). By means of Monte Carlo simulation the problem of percolation for conductive rods on a discrete insulating substrate (square lattice) is analyzed. The aspect ratio of the particles changes within the interval 1-64, the insulating defects were distributed both on the lattice and on the particles. We found that even a very small amount of the insulating defects on the particles can destroy the electrical connectivity. The critical concentration of the defects decreases as the aspect ratio of the particles increases. (paper)

  1. Surface and bulk MHD instabilities due to insulator coating imperfections

    International Nuclear Information System (INIS)

    Xu Zengyu; Reed, C.B.; Pan Chuanjie

    2002-01-01

    Experiments were performed using copper electrodes inserted into the wall of a perfectly insulated duct to simulate insulator coating flaking or cracking. The results show that surface electric potential U and MHD pressure drop ΔP exhibit a non-monotonic behavior with increasing V 0 , while the magnetic field B 0 is held constant. Additional experiments were also performed keeping all external experimental conditions fixed while measuring the change of U, V 0 , B 0 , and ΔP with increasing time. It was found that while all external experimental conditions were kept constant, the system changed by itself and U, V 0 and ΔP exhibited a non-monotonic behavior with increasing time. The results seem contrary to the law of ΔP∝V 0 B 0 n , but are consistent with conservation of energy, which implies that the change is due to some inherent feature of the system, or possibly instabilities, which may occur due to insulator coating imperfections

  2. Estimation of thermal insulation performance in multi-layer insulator for liquid helium pipe

    International Nuclear Information System (INIS)

    Shibanuma, Kiyoshi; Kuriyama, Masaaki; Shibata, Takemasa

    1991-01-01

    For a multi-layer insulator around the liquid helium pipes for cryopumps of JT-60 NBI, a multi-layer insulator composed of 10 layers, which can be wound around the pipe at the same time and in which the respective layers are in concentric circles by shifting them in arrangement, has been developed and tested. As the result, it was shown that the newly developed multi-layer insulator has better thermal insulation performance than the existing one, i.e. the heat load of the newly developed insulator composed of 10 layers was reduced to 1/3 the heat load of the existing insulator, and the heat leak at the joint of the insulator in longitudinal direction of the pipe was negligible. In order to clarify thermal characteristics of the multi-layer insulator, the heat transfer through the insulator has been analyzed considering the radiation heat transfer by the netting spacer between the reflectors, and the temperature dependence on the emissivities and the heat transmission coefficients of these two components of the insulator. The analytical results were in good agreements with the experimental ones, so that the analytical method was shown to be valid. Concerning the influence of the number of layers and the layer density on the insulation performance of the insulator, analytical results showed that the multi-layer insulator with the number of layer about N = 20 and the layer density below 2.0 layer/mm was the most effective for the liquid helium pipe of a JT-60 cryopump. (author)

  3. 30 CFR 57.12023 - Guarding electrical connections and resistor grids.

    Science.gov (United States)

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Guarding electrical connections and resistor... NONMETAL MINES Electricity Surface and Underground § 57.12023 Guarding electrical connections and resistor grids. Electrical connections and resistor grids that are difficult or impractical to insulate shall be...

  4. 30 CFR 56.12023 - Guarding electrical connections and resistor grids.

    Science.gov (United States)

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Guarding electrical connections and resistor... MINES Electricity § 56.12023 Guarding electrical connections and resistor grids. Electrical connections and resistor grids that are difficult or impractical to insulate shall be guarded, unless protection...

  5. Characterization of silicon-on-insulator wafers

    Science.gov (United States)

    Park, Ki Hoon

    The silicon-on-insulator (SOI) is attracting more interest as it is being used for an advanced complementary-metal-oxide-semiconductor (CMOS) and a base substrate for novel devices to overcome present obstacles in bulk Si scaling. Furthermore, SOI fabrication technology has improved greatly in recent years and industries produce high quality wafers with high yield. This dissertation investigated SOI material properties with simple, yet accurate methods. The electrical properties of as-grown wafers such as electron and hole mobilities, buried oxide (BOX) charges, interface trap densities, and carrier lifetimes were mainly studied. For this, various electrical measurement techniques were utilized such as pseudo-metal-oxide-semiconductor field-effect-transistor (PseudoMOSFET) static current-voltage (I-V) and transient drain current (I-t), Hall effect, and MOS capacitance-voltage/capacitance-time (C-V/C-t). The electrical characterization, however, mainly depends on the pseudo-MOSFET method, which takes advantage of the intrinsic SOI structure. From the static current-voltage and pulsed measurement, carrier mobilities, lifetimes and interface trap densities were extracted. During the course of this study, a pseudo-MOSFET drain current hysteresis regarding different gate voltage sweeping directions was discovered and the cause was revealed through systematic experiments and simulations. In addition to characterization of normal SOI, strain relaxation of strained silicon-on-insulator (sSOI) was also measured. As sSOI takes advantage of wafer bonding in its fabrication process, the tenacity of bonding between the sSOI and the BOX layer was investigated by means of thermal treatment and high dose energetic gamma-ray irradiation. It was found that the strain did not relax with processes more severe than standard CMOS processes, such as anneals at temperature as high as 1350 degree Celsius.

  6. Insulator contamination effects; Efectos de la contaminacion en aislamientos

    Energy Technology Data Exchange (ETDEWEB)

    Gonzalez, Lucia [Instituto de Investigaciones Electricas, Cuernavaca (Mexico)

    1987-12-31

    Environmental contamination deteriorates the electric insulators, mechanically as well as electrically; the mechanical problems caused by contamination are related basically with materials corrosion and degradation and the electrical problems are related to the deterioration of their dielectric rigidity. From the electrical standpoint, the type of contamination that cause more problems are divided into: marine, desert and industrial. It is not uncommon to find various combinations of these types of contamination. When the electric installations operate in polluted environments, the insulator electric behavior deteriorates, provoking increments in the operation costs for maintenance as well as for replacement. Mexico has large extensions of coasts (marine contamination), where nowadays large cities and productions centers are developed (industrial pollution); also, in some cases for the energy transportation is necessary to go through large land extensions, where no vegetation of any kind exists. For this reason the contamination effect on the electric installations must be considered in order to obtain a reliable and economical energy supply. [Espanol] La contaminacion ambiental deteriora los aisladores electricos tanto mecanica como electricamente; los problemas mecanicos por contaminacion se relacionan en forma basica con la corrosion y degradacion de los materiales, y los electricos se vinculan con el deterioro de su rigidez dielectrica. Desde el punto de vista electrico, los tipos de contaminacion que mas problemas ocasionan se dividen en: marina, desertica e industrial. Es comun encontrar diversas combinaciones de estas. Cuando las instalaciones electricas operan en ambientes contaminados, el comportamiento electrico de los aisladores se deteriora, provocando incrementos en los costos de operacion, tanto por mantenimiento como por reposicion. Mexico cuenta con grandes extensiones de costas (contaminacion marina), donde actualmente se desarrollan ciudades y

  7. Insulator contamination effects; Efectos de la contaminacion en aislamientos

    Energy Technology Data Exchange (ETDEWEB)

    Gonzalez, Lucia [Instituto de Investigaciones Electricas, Cuernavaca (Mexico)

    1986-12-31

    Environmental contamination deteriorates the electric insulators, mechanically as well as electrically; the mechanical problems caused by contamination are related basically with materials corrosion and degradation and the electrical problems are related to the deterioration of their dielectric rigidity. From the electrical standpoint, the type of contamination that cause more problems are divided into: marine, desert and industrial. It is not uncommon to find various combinations of these types of contamination. When the electric installations operate in polluted environments, the insulator electric behavior deteriorates, provoking increments in the operation costs for maintenance as well as for replacement. Mexico has large extensions of coasts (marine contamination), where nowadays large cities and productions centers are developed (industrial pollution); also, in some cases for the energy transportation is necessary to go through large land extensions, where no vegetation of any kind exists. For this reason the contamination effect on the electric installations must be considered in order to obtain a reliable and economical energy supply. [Espanol] La contaminacion ambiental deteriora los aisladores electricos tanto mecanica como electricamente; los problemas mecanicos por contaminacion se relacionan en forma basica con la corrosion y degradacion de los materiales, y los electricos se vinculan con el deterioro de su rigidez dielectrica. Desde el punto de vista electrico, los tipos de contaminacion que mas problemas ocasionan se dividen en: marina, desertica e industrial. Es comun encontrar diversas combinaciones de estas. Cuando las instalaciones electricas operan en ambientes contaminados, el comportamiento electrico de los aisladores se deteriora, provocando incrementos en los costos de operacion, tanto por mantenimiento como por reposicion. Mexico cuenta con grandes extensiones de costas (contaminacion marina), donde actualmente se desarrollan ciudades y

  8. Data compilation for radiation effects on ceramic insulators

    International Nuclear Information System (INIS)

    Fukuya, Koji; Terasawa, Mititaka; Nakahigashi, Shigeo; Ozawa, Kunio.

    1986-08-01

    Data of radiation effects on ceramic insulators were compiled from the literatures and summarized from the viewpoint of fast neutron irradiation effects. The data were classified according to the properties and ceramics. The properties are dimensional stability, mechanical property, thermal property and electrical and dielectric properties. The data sheets for each table or graph in the literatures were made. The characteristic feature of the data base was briefly described. (author)

  9. Thermal insulating panel

    Energy Technology Data Exchange (ETDEWEB)

    Hughes, J.T.

    1985-09-11

    A panel of thermal insulation material has at least one main portion which comprises a dry particulate insulation material compressed within a porous envelope so that it is rigid or substantially rigid and at least one auxiliary portion which is secured to and extends along at least one of the edges of the main portions. The auxiliary portions comprise a substantially uncompressed dry particulate insulation material contained within an envelope. The insulation material of the auxiliary portion may be the same as or may be different from the insulation material of the main portion. The envelope of the auxiliary portion may be made of a porous or a non-porous material. (author).

  10. Strain engineering and one-dimensional organization of metal-insulator domains in single-crystal vanadium dioxide beams.

    Science.gov (United States)

    Cao, J; Ertekin, E; Srinivasan, V; Fan, W; Huang, S; Zheng, H; Yim, J W L; Khanal, D R; Ogletree, D F; Grossman, J C; Wu, J

    2009-11-01

    Correlated electron materials can undergo a variety of phase transitions, including superconductivity, the metal-insulator transition and colossal magnetoresistance. Moreover, multiple physical phases or domains with dimensions of nanometres to micrometres can coexist in these materials at temperatures where a pure phase is expected. Making use of the properties of correlated electron materials in device applications will require the ability to control domain structures and phase transitions in these materials. Lattice strain has been shown to cause the coexistence of metallic and insulating phases in the Mott insulator VO(2). Here, we show that we can nucleate and manipulate ordered arrays of metallic and insulating domains along single-crystal beams of VO(2) by continuously tuning the strain over a wide range of values. The Mott transition between a low-temperature insulating phase and a high-temperature metallic phase usually occurs at 341 K in VO(2), but the active control of strain allows us to reduce this transition temperature to room temperature. In addition to device applications, the ability to control the phase structure of VO(2) with strain could lead to a deeper understanding of the correlated electron materials in general.

  11. Development of nanocomposite polymer materials for electrical and electronic applications

    International Nuclear Information System (INIS)

    Chine, Bruno

    2007-01-01

    Some results and experimental procedures of laboratory are reported in the frame of researches conducted for the development of new nanostructured composite materials. These new materials, which are constituted by an organic phase: the polymer and an inorganic phase: the silicate, are being strongly investigated nowadays so it is expected that they could provide, among other, better electrical insulation properties and flame-delay in electrical and electronic applications. The laboratory experimental work has been developed from two families of polymers, thermoplastics and thermosets and clays silicates providing lamellar type. There are now some preliminary results, such as obtaining thin films of these nanocomposite materials, their complete characterization by X-ray diffraction, scanning microscopy and thermogravimetric analysis, they do well to wait for future research activities. (author) [es

  12. Application of the thermal step method to space charge measurements in inhomogeneous solid insulating structures: A theoretical approach

    International Nuclear Information System (INIS)

    Cernomorcenco, Andrei; Notingher, Petru Jr.

    2008-01-01

    The thermal step method is a nondestructive technique for determining electric charge distribution across solid insulating structures. It consists in measuring and analyzing a transient capacitive current due to the redistribution of influence charges when the sample is crossed by a thermal wave. This work concerns the application of the technique to inhomogeneous insulating structures. A general equation of the thermal step current appearing in such a sample is established. It is shown that this expression is close to the one corresponding to a homogeneous sample and allows using similar techniques for calculating electric field and charge distribution

  13. Property comparisons of commercially available silica-based microporous insulations I. Machinability and thermal dimensional stability

    International Nuclear Information System (INIS)

    Kramer, Daniel P.; McNeil, Dennis C.; Ruhkamp, Joseph D.; Wells, Donna J.; Stringer, Robert L.; Howell, Edwin I.

    2002-01-01

    Maximizing the thermal to electrical conversion efficiency of a nuclear space power system requires that all of the available thermal energy be utilized in the most efficient manner. Microporous insulations are attractive for application in space power systems due to their very low thermal conductivity. Over the last few years, several new silica-based microporous insulating materials have become commercially available. Property comparisons of the various insulations obtained from company literature and experiments on microporous sample specimens are discussed. The results demonstrate that their machinability and thermal dimensional stability as a function of time at temperature and atmosphere are dependent on the particular material

  14. Electric polarization switching in an atomically thin binary rock salt structure

    Science.gov (United States)

    Martinez-Castro, Jose; Piantek, Marten; Schubert, Sonja; Persson, Mats; Serrate, David; Hirjibehedin, Cyrus F.

    2018-01-01

    Inducing and controlling electric dipoles is hindered in the ultrathin limit by the finite screening length of surface charges at metal-insulator junctions1-3, although this effect can be circumvented by specially designed interfaces4. Heterostructures of insulating materials hold great promise, as confirmed by perovskite oxide superlattices with compositional substitution to artificially break the structural inversion symmetry5-8. Bringing this concept to the ultrathin limit would substantially broaden the range of materials and functionalities that could be exploited in novel nanoscale device designs. Here, we report that non-zero electric polarization can be induced and reversed in a hysteretic manner in bilayers made of ultrathin insulators whose electric polarization cannot be switched individually. In particular, we explore the interface between ionic rock salt alkali halides such as NaCl or KBr and polar insulating Cu2N terminating bulk copper. The strong compositional asymmetry between the polar Cu2N and the vacuum gap breaks inversion symmetry in the alkali halide layer, inducing out-of-plane dipoles that are stabilized in one orientation (self-poling). The dipole orientation can be reversed by a critical electric field, producing sharp switching of the tunnel current passing through the junction.

  15. Development of flame retardant, radiation resistant insulating materials

    Energy Technology Data Exchange (ETDEWEB)

    Hagiwara, M.

    1984-01-01

    On the cables used for nuclear power stations, in particular those ranked as IE class, flame retardation test, simulated LOCA environment test, radiation resistance test and so on are imposed. The results of the evaluation of performance by these tests largely depend on the insulating materials mainly made of polymers. Ethylene propylene copolymer rubber has been widely used as cable insulator because of its electrical characteristics, workability, economy and relatively good radiation resistance, but it is combustible, therefore, in the practical use, it is necessary to make it fire resistant. The author et al. have advanced the research on the molecular design of new fire retarding materials, and successfully developed acenaphthylene bromide condensate, which is not only fire resistant but also effective for improving radiation resistance. The condition of flame retardant, radiation resistant auxiliary agents is explained, and there are additive type and reaction type in fire retarding materials. The synthesis of acenaphthylene bromide condensate and its effect of giving flame retardant and radiation resistant properties are reported. The characteristics of the cables insulated with the flame retardant ethylene propylene rubber containing acenaphthylene bromide condensate were tested, and the results are shown. (Kako, I.).

  16. Wall insulation system

    Energy Technology Data Exchange (ETDEWEB)

    Kostek, P.T.

    1987-08-11

    In a channel specially designed to fasten semi-rigid mineral fibre insulation to masonry walls, it is known to be constructed from 20 gauge galvanized steel or other suitable material. The channel is designed to have pre-punched holes along its length for fastening of the channel to the drywall screw. The unique feature of the channel is the teeth running along its length which are pressed into the surface of the butted together sections of the insulation providing a strong grip between the two adjacent pieces of insulation. Of prime importance to the success of this system is the recent technological advancements of the mineral fibre itself which allow the teeth of the channel to engage the insulation fully and hold without mechanical support, rather than be repelled or pushed back by the inherent nature of the insulation material. After the insulation is secured to the masonry wall by concrete nail fastening systems, the drywall is screwed to the channel.

  17. THE TECHNOLOGICAL AND EXPLOITATIVE FACTORS OF LOCAL INCREASE OF ELECTRIC FIELD STRENGTH IN THE POWER CABLE OF COAXIAL DESIGN

    Directory of Open Access Journals (Sweden)

    G. V. Bezprozvannych

    2016-12-01

    Full Text Available Introduction. Reliability of high voltage power cables in the process of long-term operation is largely due to the intensity of polymeric insulation aging. It is now established that the aging of polyethylene, which is the main material for the insulation of high voltage power cables, under the action of the electric field is determined primarily by the presence of structural heterogeneity arising both during cable production and during use. The cable is always there deviations from the ideal structure, which manifest in a deviation of diameters of conductors from nominal values; in the arrangement of the conductor and the insulation is not strictly coaxially and eccentrically; in elliptic (oval core and insulation; change in relative dielectric constant and thickness of insulation on cable length force the formation of low molecular weight products (including water in the flow at the manufacturing stage crosslinked polyethylene insulation and moisture during operation. Such defects are structural, technological and operational irregularities, which lead to a local change in the electric field. Purpose. Analysis of the influence of the eccentricity, elliptic and spherical inclusions in the electric field distribution in the power cable of a coaxial design with cross-linked polyethylene insulation, based on numerical simulation. Methodology. The bases of the numerical method of calculation of the electrical field strength are Fredholm integral equations of the first and second kind (method of secondary sources for an axially symmetric field. Analysis of the influence of irregularities, including water treeing, the shape of the sounding signal is made using the method of discrete resistive circuit inductance and capacitance of substitution with the initial conditions. Solving systems of linear algebraic equations nodal analysis performed by the sweep method. Results. The presence of the eccentricity and ellipticity in the construction of cable has

  18. Studies on Kondo insulating FeSi

    International Nuclear Information System (INIS)

    Bharathi, A.; Mani, Awadhesh; Ravindran, Nithya; Mathi Jaya, S.; Sundar, C.S.; Hariharan, Y.

    2000-01-01

    Temperature dependent electrical resistivity measurements have been carried out in Fe (1-x) Ru x Si and FeSi (1-x) Ge x to examine the robustness of the Kondo Insulating gap to substitution in the Fe and Si sublattices. The gap is seen to decrease with Ge substitution, while for Ru substitution the gap shows an initial decrease followed by an increase at higher concentration. The results can be understood in terms of the shift in the mobility edge due to disorder and/or pressure effects in combination with changes in band structure

  19. The Insulation for Machines Having a High Lifespan Expectancy, Design, Tests and Acceptance Criteria Issues

    Directory of Open Access Journals (Sweden)

    Olivier Barré

    2017-02-01

    Full Text Available The windings insulation of electrical machines will remain a topic that is updated frequently. The criteria severity requested by the electrical machine applications increases continuously. Manufacturers and designers are always confronted with new requirements or new criteria with enhanced performances. The most problematic requirements that will be investigated here are the extremely long lifespan coupled to critical operating conditions (overload, supply grid instabilities, and critical operating environments. Increasing lifespan does not have a considerable benefit because the purchasing price of usual machines has to be compared to the purchasing price and maintenance price of long lifespan machines. A machine having a 40-year lifespan will cost more than twice the usual price of a 20-year lifetime machine. Systems which need a long lifetime are systems which are crucial for a country, and those for which outage costs are exorbitant. Nuclear power stations are such systems. It is certain that the used technologies have evolved since the first nuclear power plant, but they cannot evolve as quickly as in other sectors of activities. No-one wants to use an immature technology in such power plants. Even if the electrical machines have exceeded 100 years of age, their improvements are linked to a patient and continuous work. Nowadays, the windings insulation systems have a well-established structure, especially high voltage windings. Unfortunately, a high life span is not only linked to this result. Several manufacturers’ improvements induced by many years of experiment have led to the writing of standards that help the customers and the manufacturers to regularly enhance the insulation specifications or qualifications. Hence, in this publication, the authors will give a step by step exhaustive review of one insulation layout and will take time to give a detailed report on the standards that are linked to insulation systems. No standard can

  20. Electrical conduction of a XLPE nanocomposite

    Science.gov (United States)

    Park, Yong-Jun; Sim, Jae-Yong; Lim, Kee-Joe; Nam, Jin-Ho; Park, Wan-Gi

    2014-07-01

    The resistivity, breakdown strength, and formation of space charges are very important factors for insulation design of HVDC cable. It is known that a nano-sized metal-oxide inorganic filler reduces the formation of space charges in the polymer nanocomposite. Electrical conduction of cross-linked polyethylene(XLPE) nanocomposite insulating material is investigated in this paper. The conduction currents of two kinds of XLPE nanocomposites and XLPE without nano-filler were measured at temperature of 303 ~ 363 K under the applied electric fields of 10 ~ 50 kV/mm. The current of the nanocomposite specimen is smaller than that of XLPE specimen without nano-filler. The conduction mechanism may be explained in terms of Schottky emission and multi-core model.

  1. Electric-field-induced superconductivity detected by magnetization measurements of an electric-double-layer capacitor

    International Nuclear Information System (INIS)

    Kasahara, Yuichi; Takeuchi, Yuki; Ye, Jianting; Yuan, Hongtao; Shimotani, Hidekazu; Iwasa, Yoshihiro; Nishimura, Takahiro; Sato, Tatsuya

    2010-01-01

    We report evidence for superconductivity induced by the application of strong electric fields onto the surface of a band insulator, ZrNCl, provided by the observation of a shielding diamagnetic signal. We introduced an electric-double-layer capacitor configuration and in situ magnetization measurements at low temperatures as a method to detect the novel electric-field-induced superconducting state. The results showed excellent agreement with a previous report using a transistor configuration, demonstrating that the present technique is a novel method for investigating the nonequilibrium phase induced by electric fields. (author)

  2. An experimental study of water absorption characteristics for generator stator winding insulation

    International Nuclear Information System (INIS)

    Lee, D. S.; Bae, Y. C.; Kim, H. S.; Kim, Y. H.; Lee, H.

    2004-01-01

    Leaking water coolant into stator electrical insulation is a growing concern for the aging water-cooled generator since leaks in the generator water-cooled stator winding can affect machine availability and insulation life. But a domestic techniques of such field are insufficient and depend wholly on GE or TOSHIBA technique. Therefore this paper introduces measuring principle and developed measuring system, which has been used to detecting wet absorption. We accomplished the experiment with a stator promotion of virtue which is used in actual power plant. Also, experimental method of generator stator winding, which is investigated into wet absorption test

  3. Ceramic insulation for superconducting Nb{sub 3}Sn cables; Isolation ceramique pour cables supraconducteurs en Nb{sub 3}Sn

    Energy Technology Data Exchange (ETDEWEB)

    Puigsegur, A

    2005-01-15

    Nb{sub 3}Sn is the best superconductor candidate for the realization of high field magnets (>11 Tesla), its implementation remains delicate because of the great brittleness of material after the heat treatment necessary to the formation of Nb{sub 3}Sn compounds. The conventional insulation for Nb{sub 3}Sn requires to perform, after the heat treatment, a vacuum resin impregnation, which adds to the cost and raises failure risk. We have proposed an innovating ceramic insulation deposited directly on the unreacted conducting cable. After the heat treatment of the niobium tin, we obtain a coil having a mechanical cohesion, while maintaining a proper conductor positioning and a suitable electric insulation. After a rheological study, to characterize the impregnated suspension, we have shown that using this insulation in a coil manufacture process does not affect the electrical properties of the Nb{sub 3}Sn wires. A solenoid of small dimensions was tested with success in high external magnetic fields and has produced a magnetic field of 3.8 T under 740 A. (author)

  4. Reduction of heat insulation upon soaking of the insulation layer

    Science.gov (United States)

    Achtliger, J.

    1983-09-01

    Improved thermal protection of hollow masonry by introduction of a core insulation between the inner and outer shell is discussed. The thermal conductivity of insulation materials was determined in dry state and after soaking by water with different volume-related moisture contents. The interpolated thermal conductivity values from three measured values at 10 C average temperature are presented as a function of the pertinent moisture content. Fills of expanded polystyrene, perlite and granulated mineral fibers, insulating boards made of mineral fibers and in situ cellular plastics produced from urea-formaldehyde resin were investigated. Test results show a confirmation of thermal conductivity values for insulating materials in hollow masonry.

  5. Organic superconductors with high transition temperatures and high critical magnetic fields

    International Nuclear Information System (INIS)

    Wolf, A.A.; Halpern, E.H.

    1976-01-01

    Organic compounds exhibit superconducting-like behavior, as to magnetic and electrical properties, at elevated temperatures above 21 0 K, where 21 0 K is the transition temperature of most known metallic superconducting materials. The structure of the organic materials according to this invention is a plurality of superconducting clusters, forming islands within a matrix of insulating material. The ratio of the clusters to the matrix material is a minimum at 1 : 10 4 . The organic compound comprises two distinct atomic groups termed an R group and COOM group combining as R-COOM with the COOM group clustering to form superconducting islands, within the R material matrix. 15 claims, 6 figures

  6. A ceramic radial insulation structure for a relativistic electron beam vacuum diode.

    Science.gov (United States)

    Xun, Tao; Yang, Hanwu; Zhang, Jiande; Liu, Zhenxiang; Wang, Yong; Zhao, Yansong

    2008-06-01

    For one kind of a high current diode composed of a small disk-type alumina ceramic insulator water/vacuum interface, the insulation structure was designed and experimentally investigated. According to the theories of vacuum flashover and the rules for radial insulators, a "cone-column" anode outline and the cathode shielding rings were adopted. The electrostatic field along the insulator surface was obtained by finite element analysis simulating. By adjusting the outline of the anode and reshaping the shielding rings, the electric fields were well distributed and the field around the cathode triple junction was effectively controlled. Area weighted statistical method was applied to estimate the surface breakdown field. In addition, the operating process of an accelerator based on a spiral pulse forming line (PFL) was simulated through the PSPICE software to get the waveform of charging and diode voltage. The high voltage test was carried out on a water dielectric spiral PFL accelerator with long pulse duration, and results show that the diode can work stably in 420 kV, 200 ns conditions. The experimental results agree with the theoretical and simulated results.

  7. Recent trends on electrical discharge technologies

    International Nuclear Information System (INIS)

    Nakano, Toshiki

    2007-01-01

    Recent trends on the research activities of electrical-discharge-related technologies are summarized as well as the policies of the technical committee on electrical discharges (TC-ED) of IEEJ. First, the present situation of electrical discharge research is mentioned by referring to the major subjects which TC-ED is responsible to cover. As an example of the increasingly widespread use of electrical discharge technologies, vacuum electrical insulation in a neutral beam injection system of the International Thermonuclear Experimental Reactor (ITER) device is presented. (author)

  8. Do clinical examination gloves provide adequate electrical insulation for safe hands-on defibrillation? I: Resistive properties of nitrile gloves.

    Science.gov (United States)

    Deakin, Charles D; Lee-Shrewsbury, Victoria; Hogg, Kitwani; Petley, Graham W

    2013-07-01

    Uninterrupted chest compressions are a key factor in determining resuscitation success. Interruptions to chest compression are often associated with defibrillation, particularly the need to stand clear from the patient during defibrillation. It has been suggested that clinical examination gloves may provide adequate electrical resistance to enable safe hands-on defibrillation in order to minimise interruptions. We therefore examined whether commonly used nitrile clinical examination gloves provide adequate resistance to current flow to enable safe hands-on defibrillation. Clinical examination gloves (Kimberly Clark KC300 Sterling nitrile) worn by members of hospital cardiac arrest teams were collected immediately following termination of resuscitation. To determine the level of protection afforded by visually intact gloves, electrical resistance across the glove was measured by applying a DC voltage across the glove and measuring subsequent resistance. Forty new unused gloves (control) were compared with 28 clinical (non-CPR) gloves and 128 clinical (CPR) gloves. One glove in each group had a visible tear and was excluded from analysis. Control gloves had a minimum resistance of 120 kΩ (median 190 kΩ) compared with 60 kΩ in clinical gloves (both CPR (median 140 kΩ) and non-CPR groups (median 160 kΩ)). Nitrile clinical examination gloves do not provide adequate electrical insulation for the rescuer to safely undertake 'hands-on' defibrillation and when exposed to the physical forces of external chest compression, even greater resistive degradation occurs. Further work is required to identify gloves suitable for safe use for 'hands-on' defibrillation. Copyright © 2013 Elsevier Ireland Ltd. All rights reserved.

  9. On holographic disorder-driven metal-insulator transitions

    Energy Technology Data Exchange (ETDEWEB)

    Baggioli, Matteo; Pujolàs, Oriol [Institut de Física d’Altes Energies (IFAE), Universitat Autònoma de Barcelona,The Barcelona Institute of Science and Technology,Campus UAB, 08193 Bellaterra (Barcelona) (Spain)

    2017-01-10

    We give a minimal holographic model of a disorder-driven metal-insulator transition. It consists in a CFT with a charge sector and a translation-breaking sector that interact in the most generic way allowed by the symmetries and by dynamical consistency. In the gravity dual, it reduces to a Massive Gravity-Maxwell model with a new direct coupling between the gauge field and the metric that is allowed when gravity is massive. We show that the effect of this coupling is to decrease the DC electrical conductivity generically. This gives a nontrivial check that holographic massive gravity can be consistently interpreted as disorder from the CFT perspective. The suppression of the conductivity happens to such an extent that it does not obey any lower bound and it can be very small in the insulating phase. In some cases, the large disorder limit produces gradient instabilities that hint at the formation of modulated phases.

  10. On holographic disorder-driven metal-insulator transitions

    International Nuclear Information System (INIS)

    Baggioli, Matteo; Pujolàs, Oriol

    2017-01-01

    We give a minimal holographic model of a disorder-driven metal-insulator transition. It consists in a CFT with a charge sector and a translation-breaking sector that interact in the most generic way allowed by the symmetries and by dynamical consistency. In the gravity dual, it reduces to a Massive Gravity-Maxwell model with a new direct coupling between the gauge field and the metric that is allowed when gravity is massive. We show that the effect of this coupling is to decrease the DC electrical conductivity generically. This gives a nontrivial check that holographic massive gravity can be consistently interpreted as disorder from the CFT perspective. The suppression of the conductivity happens to such an extent that it does not obey any lower bound and it can be very small in the insulating phase. In some cases, the large disorder limit produces gradient instabilities that hint at the formation of modulated phases.

  11. Comparison of electricity and heat production in combined and single-purpose systems against the background of energy saving by means of thermal insulation. Pt. 1. System comparison and general results; Vergleich der Strom- und Heizenergieerzeugung in gekoppelten und ungekoppelten Anlagen vor dem Hintergrund der Einsparmoeglichkeiten durch Waermedaemmung. T. 1. Systemvergleich und allgemeine Ergebnisse

    Energy Technology Data Exchange (ETDEWEB)

    Damberger, S.; Guenther, M.; Kluender, M.; Moeller, K.P.; Wenk, N.

    1994-06-01

    The study comprises investigations for the purpose of increasing the generation of electricity and heat in dual-purpose power plants and for promoting thermal insulation of buildings: Methods for comparatiave calculations; economic aspects; separate generation of electric power and heat; cogeneration of electric power and heat; economic efficiency of thermal insulation measures in domestic buildings; comparison of results. (HW) [Deutsch] Die Studie umfasst Untersuchungen zur Erhoehung des Anteils der gekoppelten Erzeugung von Strom und Waerme und zur vermehrten Waermedaemmung von Gebaeuden: - Methoden fuer Vergleichsrechnungen - Ekonomie - getrennte Erzeugung von Strom und Waerme - gekoppelte Erzeugung von Strom und Waerme - Wirtschaftlichkeit von Massnahmen einer Waermedaemmung von Wohngebaeuden - Vergleich der Ergebnisse. (HW)

  12. Enhancing reactor availability factor by diagnostic monitoring and data acquisition of electrical equipments

    International Nuclear Information System (INIS)

    Singh, G.

    2006-01-01

    Electrical energy has made significant contribution to rapid growth of industrial activity in the country. Development and improvement of energy conversion devices or electrical apparatus have supported the growth. Reliability is probably the most important factor in electrical supply system, not only to give uninterrupted service but to provide an economic supply. Regular diagnostic testing of electrical equipments will make a significant contribution to the reliability of electrical supply. The purpose of diagnostic monitoring is to recognize the development of faults at an early stage, which consequently allows greater freedom to schedule the outages resulting in lower downtime and lower capitalized losses. The insulation constitutes the heart of any electrical/power equipment. The insulation in power equipment in normal condition undergoes certain changes in the physical, chemical, electrical and mechanical properties. The change with respect to time in the presence of an influencing factor, more often a stress (electrical) is referred to as ageing. The deterioration of insulating material plays an important role in the assessing the condition of electrical equipments. The systematic diagnostic tests are also part of the maintenance program to ensure the continued serviceability of electrical equipments, by replacing or repairing the components likely to fail, as revealed by the test. Diagnostic tests are carried out on various electrical equipments for detection of incipient fault, location and judging their severity. (author)

  13. Electric field analysis of extra high voltage (EHV) underground cables using finite element method

    DEFF Research Database (Denmark)

    Kumar, Mantosh; Bhaskar, Mahajan Sagar; Padmanaban, Sanjeevikumar

    2017-01-01

    used for the insulator due electrical, thermal or environmental stress. Most of these problems are related to the electric field stress on the insulation of the underground cables. The objective of the electric field analysis by using different numerical techniques is to find electric field stress...... electric field stress and other parameters of EHV underground cables with given boundary conditions using 2-D electric field analysis software package (IES-ELECTRO module) which is based on the finite element method (FEM).......Transmission and Distribution of electric power through underground cables is a viable alternative to overhead lines, particularly in residential or highly populated areas. The electrical stresses are consequences of regular voltages and over voltages and the thermal stresses are related to heat...

  14. Development of electrical-erosion instrument for direct write micro-patterning on large area conductive thin films

    Energy Technology Data Exchange (ETDEWEB)

    Álvarez, Ángel Luis; Coya, Carmen; García-Vélez, Miguel [Departamento Teoría de la Señal y Comunicaciones, Sistemas Telemáticos y Computación, Escuela Técnica Superior de Ingeniería de Telecomunicación, Universidad Rey Juan Carlos, Fuenlabrada, Madrid 28943 (Spain)

    2015-08-15

    We have developed a complete instrument to perform direct, dry, and cost-effective lithography on conductive materials, based on localized electrical discharges, which avoids using masks or chemicals typical of conventional photolithography. The technique is considered fully compatible with substrate transport based systems, like roll-to-roll technology. The prototype is based on two piezo nano-steppers coupled to three linear micro-stages to cover a large scale operation from micrometers to centimeters. The operation mode consists of a spring probe biased at low DC voltage with respect to a grounded conductive layer. The tip slides on the target layer keeping contact with the material in room conditions, allowing continuous electric monitoring of the process, and also real-time tilt correction via software. The sliding tip leaves an insulating path (limited by the tip diameter) along the material, enabling to draw electrically insulated tracks and pads. The physical principle of operation is based in the natural self-limitation of the discharge due to material removal or insulation. The so produced electrical discharges are very fast, in the range of μs, so features may be performed at speeds of few cm/s, enabling scalability to large areas. The instrument has been tested on different conducting materials as gold, indium tin oxide, and aluminum, allowing the fabrication of alphanumeric displays based on passive matrix of organic light emitting diodes without the use of masks or photoresists. We have verified that the highest potential is achieved on graphene, where no waste material is detected, producing excellent well defined edges. This allows manufacturing graphene micro-ribbons with a high aspect ratio up to 1200:1.

  15. The mechanical development and construction of the insulating legs for the NSF tandem

    International Nuclear Information System (INIS)

    Leese, J.M.

    1978-06-01

    The Science Research Council is constructing at its Daresbury Laboratory a 30 MV tandem Van de Graaff accelerator which will be used as a research tool to accelerate ions of a wide range of elements. Ions are accelerated through an evacuated beam tube by maintaining a high electric field along it. The ion beam is steered and focussed by magnets situated at various positions along the tube, which, together with the beam handling elements, is supported by a vertical insulating stack. The stack consists of eight vertical columns tied together at regular intervals by stiff rings to obtain the necessary mechanical stability. Each column is made up of 'insulating legs' with tubular steel legs at the terminal and dead section positions. This report describes the manufacturing processes and their development for the insulating legs. (author)

  16. Pressure-induced metal-insulator transition in spinel compound CuV2S4

    International Nuclear Information System (INIS)

    Okada, H.; Koyama, K.; Hedo, M.; Uwatoko, Y.; Watanabe, K.

    2008-01-01

    In order to investigate the pressure effect on electrical properties of CuV 2 S 4 , we performed the electrical resistivity measurements under high pressures up to 8 GPa for a high-quality polycrystalline sample. The charge density wave (CDW) transition temperatures increase with increasing pressure. The residual resistivity rapidly increases with increasing pressure over 4 GPa, and the temperature dependence of the electrical resistivity at 8 GPa exhibits a semiconducting behavior below about 150 K, indicating that a pressure-induced metal-insulator transition occurs in CuV 2 S 4 at 8 GPa

  17. Application of Electric Double Layer Capacitor for Solar Car

    OpenAIRE

    中西, 弘一; 岸, 純男; 仲森, 昌也; 荒賀, 浩一

    2016-01-01

    This paper describes a method for efficient work of electrical energy, using DC-DC converter as insulate between battery and Electrical Double Layer Capacitor (EDLC). In case of constant-current charge to the EDLC, the efficiency of the electric power is higher, compared to the constant-voltage charge.

  18. Localization of Electrical Insulation Failures in Superconducting Collared Coils by Analysis of the Distortion of a Pulsed Magnetic Field

    CERN Document Server

    Komorowski, P A

    2000-01-01

    The localization of possible electrical faults in superconducting accelerator magnets may, in most cases, be a complex, expensive and time-consuming process. In particular, inter-turn short circuits and failures of the ground insulation are well detectable when the magnet is collared, but often disappear after disassembly for repair due to the release of the pre-stress in the coils. The fault localization method presented in this paper is based on the measurement and analysis of the magnetic field generated inside the magnet aperture by a high voltage pulse. The presence of the fault modifies the distribution of the current in the coils and produces a distortion of the magnetic field. The described method aims at locating both the longitudinal and azimuthal position of the fault-affected area. The test method, the transient case FEM models and the implemented experimental set-up are presented and discussed for the LHC dipole models.

  19. Low-Temperature Fabrication of Robust, Transparent, and Flexible Thin-Film Transistors with a Nanolaminated Insulator.

    Science.gov (United States)

    Kwon, Jeong Hyun; Park, Junhong; Lee, Myung Keun; Park, Jeong Woo; Jeon, Yongmin; Shin, Jeong Bin; Nam, Minwoo; Kim, Choong-Ki; Choi, Yang-Kyu; Choi, Kyung Cheol

    2018-05-09

    The lack of reliable, transparent, and flexible electrodes and insulators for applications in thin-film transistors (TFTs) makes it difficult to commercialize transparent, flexible TFTs (TF-TFTs). More specifically, conventional high process temperatures and the brittleness of these elements have been hurdles in developing flexible substrates vulnerable to heat. Here, we propose electrode and insulator fabrication techniques considering process temperature, transmittance, flexibility, and environmental stability. A transparent and flexible indium tin oxide (ITO)/Ag/ITO (IAI) electrode and an Al 2 O 3 /MgO (AM)-laminated insulator were optimized at the low temperature of 70 °C for the fabrication of TF-TFTs on a polyethylene terephthalate (PET) substrate. The optimized IAI electrode with a sheet resistance of 7 Ω/sq exhibited the luminous transmittance of 85.17% and maintained its electrical conductivity after exposure to damp heat conditions because of an environmentally stable ITO capping layer. In addition, the electrical conductivity of IAI was maintained after 10 000 bending cycles with a tensile strain of 3% because of the ductile Ag film. In the metal/insulator/metal structure, the insulating and mechanical properties of the optimized AM-laminated film deposited at 70 °C were significantly improved because of the highly dense nanolaminate system, compared to those of the Al 2 O 3 film deposited at 70 °C. In addition, the amorphous indium-gallium-zinc oxide (a-IGZO) was used as the active channel for TF-TFTs because of its excellent chemical stability. In the environmental stability test, the ITO, a-IGZO, and AM-laminated films showed the excellent environmental stability. Therefore, our IGZO-based TFT with IAI electrodes and the 70 °C AM-laminated insulator was fabricated to evaluate robustness, transparency, flexibility, and process temperature, resulting in transfer characteristics comparable to those of an IGZO-based TFT with a 150 °C Al 2 O 3

  20. Electric strength of metal-ceramic brazed units of thermionic energy converters in cesium vapours

    International Nuclear Information System (INIS)

    Belousenko, A.P.; Vasilchenko, A.V.; Nikolaev, Y.V.

    1989-01-01

    The investigation of electric strength characteristics of the hollow metal-ceramic brazed units of thermionic energy converters with the insulator 1 = 10-50 mm from polycrystal aluminum oxide at the temperature T = 450-750 degrees and the cesium vapour pressure P Cs = 10 - 1 -10 3 Pa has been carried out. The experimental dependencies of the break-down voltage of the brazed units on the temperature, parameter P Cs · 1 and the value of surface electric resistance of the insulators are given as well as the empiric equations obtained with the help of experimental data for calculating the break-down voltage. A mechanism of ceramic insulator influence on electric strength characteristics of the cesium gap is investigated. A breakdown model explaining this influence is proposed

  1. Nonlinear Dielectric Response of Water Treed XLPE Cable Insulation

    Energy Technology Data Exchange (ETDEWEB)

    Hvidsten, Sverre

    1999-07-01

    frequency domain dielectric response was larger, and found to be more nonlinear than values measured in time domain. This thesis describes a new mechanism for the nonlinear dielectric response. It is assumed that at low or no applied electric stress the water treed region is characterised by spherical micro voids filled with liquid water separated by channels of crazed insulation. The effect of increasing the test voltage is to cause Maxwell mechanical tensile stresses strong enough to open up the crazing zones and elongate the water droplets into the mechanically weak crazing zones. Finite Element Method (FEM) calculations show that the effect of the re-opening of crazing zones by an increased test voltage, strongly increases the dielectric loss of the water treed insulation. This is qualitatively in good agreement with the experimental results obtained on water treed insulation, where increasing the test voltage above a certain value caused the losses to increase. The typical frequency independent dielectric response of water treed insulation can, however, not be explained by this model. Numerical calculations of losses, indicated that the mechanism of voltage assisted ingress of water is more likely in treed regions with rather low contents of water. The micro-FTIR measurements of single vented water trees indicated that such regions were likely to be present 3-400 (my)m within the tree tip, and close to the insulation screen. The process of refilling water into water tree structures is likely to be associated with a hysteresis effect. When removing (or reducing) the electric field, mechanical relaxation causes the channel to collapse and to slowly recover its former structure. Dielectric response measurements showed that a hysteresis was typically present when the response was nonlinear.

  2. Propagation Characteristics of Multilayer Hybrid Insulator-Metal-Insulator and Metal-Insulator-Metal Plasmonic Waveguides

    Directory of Open Access Journals (Sweden)

    M. Talafi Noghani

    2014-02-01

    Full Text Available Propagation characteristics of symmetrical and asymmetrical multilayer hybrid insulator-metal-insulator (HIMI and metal-insulator-metal (HMIM plasmonic slab waveguides are investigated using the transfer matrix method. Propagation length (Lp and spatial length (Ls are used as two figures of merit to qualitate the plasmonic waveguides. Symmetrical structures are shown to be more performant (having higher Lp and lower Ls, nevertheless it is shown that usage of asymmetrical geometry could compensate for the performance degradation in practically realized HIMI waveguides with different substrate materials. It is found that HMIM slab waveguide could support almost long-range subdiffraction plasmonic modes at dimensions lower than the spatial length of the HIMI slab waveguide.

  3. Damages of electrical insulation of cable products used at NPP`s and technique of their detection and operative control; Povrezhdeniya v ehlektricheskoj izolyatsii kabel`nykh izdulij, ehkspluatirue mykh na atomnykh ehlektrostantsiyakh i metody ikh obnaruzheniya i operativnogo kontro lya

    Energy Technology Data Exchange (ETDEWEB)

    Valeev, R S; Filatov, N I

    1994-12-31

    Analysis of possible damages in electrical insulation of cable products under their application at NPP`s is conducted. Basic methods for detecting such damages and rapid control of technical condition of cable products during the operation are considered.

  4. Bill for a new organization of the electricity market. Final Text

    International Nuclear Information System (INIS)

    2010-01-01

    This text contains the new arrangements introduced to organize the concurrence and the competitiveness in the distribution of the electricity produced in France notably that produced by EDF in the French nuclear power plants. It defines the legal framework for agreements between EDF and electricity providers, i.e. prices and quantities of electricity, purchase obligations. It also defines obligations of the providers with respect to users. It addresses the relationship between local communities and these providers, tariffs, works realized on the network. It also addresses the purchase price of hydroelectricity and of electricity produced from biomass, gas tariff

  5. Workshop on technical assessment of industrial thermal insulation materials: summary

    International Nuclear Information System (INIS)

    Peterson, S.

    1976-07-01

    Over 80 participants representing 50 organizations met to discuss the report, Industrial Thermal Insulation--An Assessment, ORNL/TM-5283. Presentations on the performance of available materials, economic considerations, and measurement problems were followed by discussion. A final wrap-up session concluded that the report was valuable in pointing the direction for needed effort in the area, confirmed the indicated actions needed to further industrial application of insulation, and called for future meetings to continue the dialogue between the various facets of the industry

  6. Industrial production of insulators using isostatic compaction method

    Energy Technology Data Exchange (ETDEWEB)

    Drugoveiko, O.P.; Ermolaeva, L.V.; Koren' , M.G.; Kreimer, B.D.; Panichev, G.I.; Ponomarev, A.P.; Rutkovskii, V.N.

    1985-07-01

    The process of shaping ceramic products from powders using isostatic compaction method is finding increasing industrial application. The production of electrical-engineering porcelain using isostatic compaction method is, according to the authors, a promising direction since this method permits one to obtain large and complex shaped products having uniform density distribution. The authors introduce an automatic isostatic compaction line at the ''Proletarii'' Factory for the production of the IOS-110-20000UKhL, T1 type insulators having the described dimensions. According to the technological process developed at the ''Elektrokeramika'' Production Complex, insulators were manufactured on the isostatic compaction line from the G-33 mass. Presspowder having a moisture content of 0.3-0.6% and a particle size of 90-160 micrometers was obtained in a spray dryer using disk spraying. The authors studied saturability by moisture of the powder obtained.

  7. A high-temperature silicon-on-insulator stress sensor

    International Nuclear Information System (INIS)

    Wang Zheyao; Tian Kuo; Zhou Youzheng; Pan Liyang; Liu Litian; Hu Chaohong

    2008-01-01

    A piezoresistive stress sensor is developed using silicon-on-insulator (SOI) wafers and calibrated for stress measurement for high-temperature applications. The stress sensor consists of 'silicon-island-like' piezoresistor rosettes that are etched on the SOI layer. This eliminates leakage current and enables excellent electrical insulation at high temperature. To compensate for the measurement errors caused by the misalignment of the piezoresistor rosettes with respect to the crystallographic axes, an anisotropic micromachining technique, tetramethylammonium hydroxide etching, is employed to alleviate the misalignment issue. To realize temperature-compensated stress measurement, a planar diode is fabricated as a temperature sensor to decouple the temperature information from the piezoresistors, which are sensitive to both stress and temperature. Design, fabrication and calibration of the piezoresistors are given. SOI-related characteristics such as piezoresistive coefficients and temperature coefficients as well as the influence of the buried oxide layer are discussed in detail

  8. Effects of electric field and magnetic induction on spin injection into organic semiconductors

    International Nuclear Information System (INIS)

    Wang, Y.M.; Ren, J.F.; Yuan, X.B.; Dou, Z.T.; Hu, G.C.

    2011-01-01

    Spin-polarized injection and transport into ferromagnetic/organic semiconductor structure are studied theoretically in the presence of the external electric field and magnetic induction. Based on the spin-drift-diffusion theory and Ohm's law, we obtain the charge current polarization, which takes into account the special carriers of organic semiconductors. From the calculation, it is found that the current spin polarization is enhanced by several orders of magnitude by tuning the magnetic induction and electric fields. To get an apparent current spin polarization, the effects of spin-depended interfacial resistances and the special carriers in the organic semiconductor, which are polarons and bipolarons, are also discussed. -- Research highlights: → Current polarization in ferromagnetic/organic semiconductor structure is obtained. → Calculations are based on spin-drift-diffusion theory and Ohm's law. → Current polarization is enhanced by tuning magnetic induction and electric fields. → Effects of interfacial resistances and the special carriers are also discussed.

  9. 78 FR 38455 - Energy Conservation Program: Test Procedures for Electric Motors

    Science.gov (United States)

    2013-06-26

    ... windings, which protects them from condensation, moisture, dirt, and debris. This insulation typically... and Moisture Resistant Windings 4. Inverter-Capable Electric Motors 5. Totally Enclosed Non-Ventilated... set. [cir] Definite-purpose inverter- fed electric motor. [cir] Electric motor with moisture resistant...

  10. Insulation co-ordination aspects for power stations with generator circuit-breakers

    International Nuclear Information System (INIS)

    Sanders, M.; Koeppl, G.; Kreuzer, J.

    1995-01-01

    The generator circuit-breaker (gen. c.b.) located between the generator and the step-up transformer, is now being applied world-wide. It has become a recognized electrical component of power stations which is largely due to economical advantages and increased power station availability. Technical protection considerations for power stations have always been the reason for discussion and the object of improvement. With the use of a gen. c.b., some points of view need to be considered anew. Not only the protection system in case of fault conditions will be influenced, but also the insulation co-ordination philosophy. Below the results of some calculations concerning expected overvoltages are presented. These calculations are based on a transformer rated 264/15.5kV, 220 MVA. But the results are transferable to other power plants. Some measurements carried out on a transformer of the same rating complement the calculations. The findings may contribute to an improvement in insulation co-ordination and protection of the electrical system generator--step-up transformer

  11. Passive Collecting of Solar Radiation Energy using Transparent Thermal Insulators, Energetic Efficiency of Transparent Thermal Insulators

    Directory of Open Access Journals (Sweden)

    Smajo Sulejmanovic

    2014-11-01

    Full Text Available This paper explains passive collection of solar radiation energy using transparent thermal insulators. Transparent thermal insulators are transparent for sunlight, at the same time those are very good thermal insulators. Transparent thermal insulators can be placed instead of standard conventional thermal insulators and additionally transparent insulators can capture solar radiation, transform it into heat and save heat just as standard insulators. Using transparent insulators would lead to reduce in usage of fossil fuels and would help protection of an environment and reduce effects of global warming, etc.

  12. Analysis of electrical tree propagation in XLPE power cable insulation

    International Nuclear Information System (INIS)

    Bao Minghui; Yin Xiaogen; He Junjia

    2011-01-01

    Electrical treeing is one of the major breakdown mechanisms for solid dielectrics subjected to high electrical stress. In this paper, the characteristics of electrical tree growth in XLPE samples have been investigated. XLPE samples are obtained from a commercial XLPE power cable, in which electrical trees have been grown from pin to plane in the frequency range of 4000-10,000 Hz, voltage range of 4-10 kV, and the distances between electrodes of 1 and 2 mm. Images of trees and their growing processes were taken by a CCD camera. The fractal dimensions of electric trees were obtained by using a simple box-counting technique. The results show that the tree growth rate and fractal dimension was bigger when the frequency or voltage was higher, or the distance between electrodes was smaller. Contrary to our expectation, it has been found that when the distance between electrodes changed from 1 to 2 mm, the required voltage of the similar electrical trees decreased only 1or 2 kV. In order to evaluate the difficulties of electrical tree propagation in different conditions, a simple energy threshold analysis method has been proposed. The threshold energy, which presents the minimum energy that a charge carrier in the well at the top of the tree should have to make the tree grow, has been computed considering the length of electrical tree, the fractal dimension, and the growth time. The computed results indicate that when one of the three parameters of voltage, frequency, and local electric field increase, the trends of energy threshold can be split into 3 regions.

  13. Widely tunable microwave phase shifter based on silicon-on-insulator dual-microring resonator

    DEFF Research Database (Denmark)

    Pu, Minhao; Liu, Liu; Xue, Weiqi

    2010-01-01

    We propose and demonstrate tunable microwave phase shifters based on electrically tunable silicon-on-insulator microring resonators. The phase-shifting range and the RF-power variation are analyzed. A maximum phase-shifting range of 0~600° is achieved by utilizing a dual-microring resonator...

  14. Opportunities in chemistry and materials science for topological insulators and their nanostructures

    KAUST Repository

    Kong, Desheng

    2011-10-24

    Electrical charges on the boundaries of topological insulators favour forward motion over back-scattering at impurities, producing low-dissipation, metallic states that exist up to room temperature in ambient conditions. These states have the promise to impact a broad range of applications from electronics to the production of energy, which is one reason why topological insulators have become the rising star in condensed-matter physics. There are many challenges in the processing of these exotic materials to use the metallic states in functional devices, and they present great opportunities for the chemistry and materials science research communities. © 2011 Macmillan Publishers Limited. All rights reserved.

  15. Advances in high voltage insulation and arc interruption in SF6 and vacuum

    CERN Document Server

    Maller, V N

    1982-01-01

    Advances in High Voltage Insulation and Arc Interruption in SF6 and Vacuum deals with high voltage breakdown and arc extinction in sulfur hexafluoride (SF6) and high vacuum, with special emphasis on the application of these insulating media in high voltage power apparatus and devices. The design and developmental aspects of various high voltage power apparatus using SF6 and high vacuum are highlighted. This book is comprised of eight chapters and opens with a discussion on electrical discharges in SF6 and high vacuum, along with the properties and handling of SF6 gas. The following chapters fo

  16. 75 FR 28004 - Credit Reforms in Organized Wholesale Electric Markets; Notice Establishing Date for Comments

    Science.gov (United States)

    2010-05-19

    ... Proposed Rulemaking on Credit Reforms in Organized Wholesale Electric Markets.\\1\\ Specifically, the... counterparty to transactions in their markets \\1\\ Credit Reforms in Organized Wholesale Electric Markets, 130... DEPARTMENT OF ENERGY Federal Energy Regulatory Commission [Docket No. RM10-13-000] Credit Reforms...

  17. Report for the Prime Minister. Making the future French electric power organization a success

    International Nuclear Information System (INIS)

    Dumont, J.L.

    1998-01-01

    This report from the French Deputy of the Meuse region aims at taking stock of four main questions raised by the future organization of the French electric power industry in the context of the opening of the European power market: the public utility of electric power, the future missions of Electricite de france (EdF) company, the questions in relation with the personnel status in the electric power industry, and the status of the regulating authority. In order to give some elements of answer to these questions, the report has been divided into 2 parts: part 1 presents the power production, transport and distribution in the future electric power regulation (the renewal of nuclear facilities, the building of non-nuclear units, the exploitation of the power distribution network, the accounting dissociation and the transparency of accountancy, the organization of network access, the eligible clients, the direct power lines, the obligations of purchase, the distribution and the role of local authorities). Part 2 presents the four main stakes of the modernization of the French electric power sector: the electric power public utility (public concern and rights, government policy, sustain of innovation, environment protection and energy mastery, the transportation and distribution networks, the role of operators and the financing), the future evolution of EdF (missions and organization, future of the public company), the social modernization of the electric power sector (present day status, adaptation, evolution, pensions), the organization and role of the future regulation authority. The propositions of the author are reported in the appendix. (J.S.)

  18. Self-Healing Wire Insulation

    Science.gov (United States)

    Parrish, Clyde F. (Inventor)

    2012-01-01

    A self-healing system for an insulation material initiates a self-repair process by rupturing a plurality of microcapsules disposed on the insulation material. When the plurality of microcapsules are ruptured, reactants within the plurality of microcapsules react to form a replacement polymer in a break of the insulation material. This self-healing system has the ability to repair multiple breaks in a length of insulation material without exhausting the repair properties of the material.

  19. Ormosil Beads for Insulation of Ground Cryogenic Storage Tanks, Phase II

    Data.gov (United States)

    National Aeronautics and Space Administration — Organically modified silica (Ormosil) aerogel beads developed at Aspen Aerogels, Inc. offer several advantages for retrofitting perlite insulation in NASA's ground...

  20. Electric motor handbook

    CERN Document Server

    Chalmers, B J

    2013-01-01

    Electric Motor Handbook aims to give practical knowledge in a wide range of capacities such as plant design, equipment specification, commissioning, operation and maintenance. The book covers topics such as the modeling of steady-state motor performance; polyphase induction, synchronous, and a.c. commutator motors; ambient conditions, enclosures, cooling and loss dissipation; and electrical supply systems and motor drives. Also covered are topics such as variable-speed drives and motor control; materials and motor components; insulation types, systems, and techniques; and the installation, sit