Sample records for electrical insulators fusion

  1. Electrically insulating coatings for V-Li self-cooled blanket in a fusion system

    Natesan, K.; Reed, C. B.; Uz, M.; Park, J. H.; Smith, D. L.


    The blanket system is one of the most important components in a fusion reactor because it has a major impact on both the economics and safety of fusion energy. The primary functions of the blanket in a deuterium/tritium-fueled fusion reactor are to convert the fusion energy into sensible heat and to breed tritium for the fuel cycle. The liquid-metal blanket concept requires an electrically insulating coating on the first-wall structural material to minimize the magnetohydrodynamic pressure drop that occurs during the flow of liquid metal in a magnetic field. Based on the thermodynamics of interactions between the coating and the liquid lithium on one side and the structural V-base alloy on the other side, several coating candidates are being examined to perform the insulating function over a wide range of temperatures and lithium chemistries.

  2. Electric fields and electrical insulation

    McAllister, Iain Wilson


    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......, it is amply demonstrated that such an approach can lead to significant progress in many areas of electrical insulation....

  3. A study on the fusion reactor - Development of electrical insulation coating processes for vacuum vessel components of KT-2 tokamak by plasma spray techniques

    Hong, Sang Hee; Choi, Byung Yong; Ahn, Hyun; Ju, Won Tae; Eom, You Sub [Seoul National University, Seoul (Korea, Republic of)


    For the fabrication of insulation coatings with good vacuum tightness, mechanical and electrical properties needed for voltage breaker and plasma facing components of tokamak vacuum vessel, a plasma spraying system equipped= with an improved power supply and a precision powder feeder is employed for the development of the optimum processes for ceramic insulation coatings. The material properties of the ceramic coatings for tokamak vacuum vessel components are evaluated by material tests and analyses to determine optimum processing parameters for insulation coatings. As a result of material evaluation for Al{sub 2}O{sub 3} and Al{sub 2}O{sub 3}-TiO{sub 2} ceramic insulation coatings fabricated, Al{sub 2}O{sub 3}-3%TiO{sub 2} ceramic turn out to be the best insulation coating for tokamak use in respect of electrical and mechanical properties. Al{sub 2}O{sub 3} coating with dielectric strength values of more than 26 kV/mm can also be applicable to tokamak vacuum vessel components for electric insulation by improving its low adhesive strength. 23 refs., 9 tabs., 14 figs. (author)

  4. Electric Insulation Detection Method for High-voltage Insulators

    Wang Jiajun


    Full Text Available The principle of partial discharge detection is that through partial bridged discharge under high voltage electric field, it detects the inner air-filled cavity of high-voltage insulators. And it is a nondestructive detection method based on discharge magnitude to judge the insulation quality. The detecting system that adopts the partial discharge detection is more rigorous than testing system for electricity products, which must have small discharge capacity and higher sensitivity. This paper describes the principles of partial discharge detection and analysis insulation detection.

  5. Electrically Tunable Magnetism in Magnetic Topological Insulators

    Wang, Jing; Lian, Biao; Zhang, Shou-Cheng


    The external controllability of the magnetic properties in topological insulators would be important both for fundamental and practical interests. Here we predict the electric-field control of ferromagnetism in a thin film of insulating magnetic topological insulators. The decrease of band inversion by the application of electric fields results in a reduction of magnetic susceptibility, and hence in the modification of magnetism. Remarkably, the electric field could even induce the magnetic quantum phase transition from ferromagnetism to paramagnetism. We further propose a transistor device in which the dissipationless charge transport of chiral edge states is controlled by an electric field. In particular, the field-controlled ferromagnetism in a magnetic topological insulator can be used for voltage based writing of magnetic random access memories in magnetic tunnel junctions. The simultaneous electrical control of magnetic order and chiral edge transport in such devices may lead to electronic and spintronic applications for topological insulators.

  6. Rheological behavior and cryogenic properties of cyanate ester/epoxy insulation material for fusion superconducting magnet

    Wu, Z. X.; Huang, C. J. [Key Laboratory of Cryogenics, Technical Institute of Physics and Chemistry, Chinese Academy of Sciences, Beijing 100190, PR (China); Li, L. F. [Key Laboratory of Cryogenics, Technical Institute of Physics and Chemistry, Chinese Academy of Sciences, Beijing 100190, PR China and State Key Laboratory of Technologies in Space Cryogenic Propellants, Technical Institute of Physics and Chemistry, C (China); Li, J. W. [Key Laboratory of Cryogenics, Technical Institute of Physics and Chemistry, Chinese Academy of Sciences, Beijing 100190, PR China and University of Chinese Academy of Sciences, Beijing 100049, PR (China); Tan, R.; Tu, Y. P. [North China Electric Power University, Beijing 102206, PR (China)


    In a Tokamak fusion reactor device like ITER, insulation materials for superconducting magnets are usually fabricated by a vacuum pressure impregnation (VPI) process. Thus these insulation materials must exhibit low viscosity, long working life as well as good radiation resistance. Previous studies have indicated that cyanate ester (CE) blended with epoxy has an excellent resistance against neutron irradiation which is expected to be a candidate insulation material for a fusion magnet. In this work, the rheological behavior of a CE/epoxy (CE/EP) blend containing 40% CE was investigated with non-isothermal and isothermal viscosity experiments. Furthermore, the cryogenic mechanical and electrical properties of the composite were evaluated in terms of interlaminar shear strength and electrical breakdown strength. The results showed that CE/epoxy blend had a very low viscosity and an exceptionally long processing life of about 4 days at 60 °C.

  7. Electrically insulated MLI and thermal anchor

    Kamiya, Koji; Furukawa, Masato; Hatakenaka, Ryuta; Miyakita, Takeshi; Murakami, Haruyuki; Kizu, Kaname; Tsuchiya, Katsuhiko; Koidea, Yoshihiko; Yoshida, Kiyoshi


    The thermal shield of JT-60SA is kept at 80 K and will use the multilayer insulation (MLI) to reduce radiation heat load to the superconducting coils at 4.4 K from the cryostat at 300 K. Due to plasma pulse operation, the MLI is affected by eddy current in toroidal direction. The MLI is designed to suppress the current by electrically insulating every 20 degree in the toroidal direction by covering the MLI with polyimide films. In this paper, two kinds of designs for the MLI system are proposed, focusing on a way to overlap the layers. A boil-off calorimeter method and temperature measurement has been performed to determine the thermal performance of the MLI system. The design of the electrical insulated thermal anchor between the toroidal field (TF) coil and the thermal shield is also explained.

  8. Ceramic electrical insulation for electrical coils, transformers, and magnets

    Rice, John A.; Hazelton, Craig S.; Fabian, Paul E.


    A high temperature electrical insulation is described, which is suitable for electrical windings for any number of applications. The inventive insulation comprises a cured preceramic polymer resin, which is preferably a polysiloxane resin. A method for insulating electrical windings, which are intended for use in high temperature environments, such as superconductors and the like, advantageously comprises the steps of, first, applying a preceramic polymer layer to a conductor core, to function as an insulation layer, and second, curing the preceramic polymer layer. The conductor core preferably comprises a metallic wire, which may be wound into a coil. In the preferred method, the applying step comprises a step of wrapping the conductor core with a sleeve or tape of glass or ceramic fabric which has been impregnated by a preceramic polymer resin. The inventive insulation system allows conducting coils and magnets to be fabricated using existing processing equipment, and maximizes the mechanical and thermal performance at both elevated and cryogenic temperatures. It also permits co-processing of the wire and the insulation to increase production efficiencies and reduce overall costs, while still remarkably enhancing performance.

  9. Modification of electrical properties of topological insulators

    Sharma, Peter Anand


    Ion implantation or deposition can be used to modify the bulk electrical properties of topological insulators. More particularly, ion implantation or deposition can be used to compensate for the non-zero bulk conductivity due to extrinsic charge carriers. The direct implantation of deposition/annealing of dopants allows better control over carrier concentrations for the purposes of achieving low bulk conductivity. Ion implantation or deposition enables the fabrication of inhomogeneously doped structures, enabling new types of device designs.

  10. Integrated Electrical Wire Insulation Repair System

    Williams, Martha; Jolley, Scott; Gibson, Tracy; Parks, Steven


    An integrated system tool will allow a technician to easily and quickly repair damaged high-performance electrical wire insulation in the field. Low-melt polyimides have been developed that can be processed into thin films that work well in the repair of damaged polyimide or fluoropolymer insulated electrical wiring. Such thin films can be used in wire insulation repairs by affixing a film of this low-melt polyimide to the damaged wire, and heating the film to effect melting, flow, and cure of the film. The resulting repair is robust, lightweight, and small in volume. The heating of this repair film is accomplished with the use of a common electrical soldering tool that has been modified with a special head or tip that can accommodate the size of wire being repaired. This repair method can furthermore be simplified for the repair technician by providing replaceable or disposable soldering tool heads that have repair film already "loaded" and ready for use. The soldering tool heating device can also be equipped with a battery power supply that will allow its use in areas where plug-in current is not available

  11. Physical and mechanical characteristics and chemical compatibility of aluminum nitride insulator coatings for fusion reactor applications

    Natesan, K.; Rink, D.L. [Argonne National Lab., IL (United States). Energy Technology Div.


    The blanket system is one of the most important components in a fusion reactor because it has a major impact on both the economics and safety of fusion energy. The primary functions of the blanket in a deuterium/tritium-fueled fusion reactor are to convert the fusion energy into sensible heat and to breed tritium for the fuel cycle. The Blanket Comparison and Selection Study, conducted earlier, described the overall comparative performance of various concepts, including liquid metal, molten salt, water, and helium. Based on the requirements for an electrically insulating coating on the first-wall structural material to minimize the MHD pressure drop during the flow of liquid metal in a magnetic field, AlN was selected as a candidate coating material for the Li self-cooled blanket concept. This report discusses the results from an ongoing study of physical and mechanical characteristics and chemical compatibility of AlN electrical insulator coatings in a liquid Li environment. Details are presented on the AlN coating fabrication methods, and experimental data are reported for microstructures, chemistry of coatings, pretreatment of substrate, heat treatment of coatings, hardness data for coatings, coating/lithium interactions, and electrical resistance before and after exposure to lithium. Thermodynamic calculations are presented to establish regions of stability for AlN coatings in an Li environment as a function of O concentration and temperature, which can aid in-situ development of AlN coatings in Li.

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

    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.

  13. High voltage and electrical insulation engineering

    Arora, Ravindra


    "The book is written for students as well as for teachers and researchers in the field of High Voltage and Insulation Engineering. It is based on the advance level courses conducted at TU Dresden, Germany and Indian Institute of Technology Kanpur, India. The book has a novel approach describing the fundamental concept of field dependent behavior of dielectrics subjected to high voltage. There is no other book in the field of high voltage engineering following this new approach in describing the behavior of dielectrics. The contents begin with the description of fundamental terminology in the subject of high voltage engineering. It is followed by the classification of electric fields and the techniques of field estimation. Performance of gaseous, liquid and solid dielectrics under different field conditions is described in the subsequent chapters. Separate chapters on vacuum as insulation and the lightning phenomenon are included"--

  14. 30 CFR 75.513 - Electric conductor; capacity and insulation.


    ... § 75.513 Electric conductor; capacity and insulation. All electric conductors shall be sufficient in size and have adequate current carrying capacity and be of such construction that a rise in temperature... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Electric conductor; capacity and insulation....

  15. Plasma etching to enhance the surface insulating stability of alumina for fusion applications

    M. Malo


    Full Text Available A significant increase in the surface electrical conductivity of alumina, considered one of the most promising insulating materials for numerous applications in fusion devices, has been observed during ion bombardment in vacuum due to oxygen loss by preferential sputtering. Although this is expected to cause serious limitations to insulating components functionality, recent studies showed it is possible to restore the damaged lattice by oxygen reincorporation during thermal treatments in air. These studies also revealed a correlation between conductivity and ion beam induced luminescence, which is being used to monitor surface electrical conductivity degradation and help qualify the post irradiation recovery. Work now carried out for Wesgo alumina considers oxygen implantation and plasma etching as additional methods to improve recovered layer depth and quality. Both conductivity and luminescence results indicate the potential use of plasma etching not only for damage recovery, but also as a pre-treatment to enhance material stability during irradiation.

  16. Electrical control of spin in topological insulators

    Chang, Kai


    All-electrical manipulation of electron spin in solids becomes a central issue of quantum information processing and quantum computing. The many previous proposals are based on spin-orbit interactions in semiconductors. Topological insulator, a strong spin-orbit coupling system, make it possible to control the spin transport electrically. Recent calculations proved that external electric fields can drive a HgTe quantum well from normal band insulator phase to topological insulator phase [1]. Since the topological edge states are robust against local perturbation, the controlling of edge states using local fields is a challenging task. We demonstrate that a p-n junction created electrically in HgTe quantum wells with inverted band structure exhibits interesting intraband and interband tunneling processes. We find a perfect intraband transmission for electrons injected perpendicularly to the interface of the p-n junction. The opacity and transparency of electrons through the p-n junction can be tuned by changing the incidence angle, the Fermi energy and the strength of the Rashba spin-orbit interaction (RSOI). The occurrence of a conductance plateau due to the formation of topological edge states in a quasi-one-dimensional p-n junction can be switched on and off by tuning the gate voltage. The spin orientation can be substantially rotated when the samples exhibit a moderately strong RSOI [2]. An electrical switching of the edge-state transport can also be realized using quantum point contacts in quantum spin Hall bars. The switch-on/off of the edge channel is caused by the finite size effect of the quantum point contact and therefore can be manipulated by tuning the voltage applied on the split gate [3,4]. The magnetic ions doped on the surface of 3D TI can be correlated through the helical electrons. The RKKY interaction mediated by the helical Dirac electrons consists of the Heisenberg-like, Ising-like, and Dzyaloshinskii-Moriya (DM)-like terms, which can be tuned

  17. Field experience and electrical characteristics of punctured porcelain suspension insulators

    Nguyen, D.H. [Institut de Recherche d`Hydro-Quebec, Varennes, PQ (Canada)


    The condition and electrical characteristics of porcelain insulators in service at Hydro-Quebec were investigated through a series of live-line tests. More than 2,000 insulator strings on the distribution system were checked under energized field conditions using different detection devices. About 200 faulty insulators and representative sound insulators were removed and analyzed in the laboratory in an effort to assess the efficiency of the different devices used to detect the faulty insulators. The detection of faulty insulator units is necessary to maintain system reliability. Insulator deterioration was found to be caused by inherent porosity and manufacturing defects in the porcelain shell and by expansion forces produced by insulator pin-hole cement. 2 refs., 3 figs.

  18. 30 CFR 77.503 - Electric conductors; capacity and insulation.


    ... UNDERGROUND COAL MINES Electrical Equipment-General § 77.503 Electric conductors; capacity and insulation. Electric conductors shall be sufficient in size and have adequate current carrying capacity and be of such... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Electric conductors; capacity and...

  19. Evaluation of transformer insulating oil quality using NIR, fluorescence, and NMR spectroscopic data fusion.

    Godinho, Mariana S; Blanco, Marcos R; Gambarra Neto, Francisco F; Lião, Luciano M; Sena, Marcelo M; Tauler, Romà; de Oliveira, Anselmo E


    Power transformers are essential components in electrical energy distribution. One of their most important parts is the insulation system, consisting of Kraft paper immersed in insulating oil. Interfacial tension and color are major parameters used for assessing oil quality and the system׳s degradation. This work proposes the use of near infrared (NIR), molecular fluorescence, and (1)H nuclear magnetic resonance (NMR) spectroscopy methods combined with chemometric multivariate calibration methods (Partial Least Squares - PLS) to predict interfacial tension and color in insulating mineral oil samples. Interfacial tension and color were also determined using tensiometry and colorimetry as standard reference methods, respectively. The best PLS model was obtained when NIR, fluorescence, and NMR data were combined (data fusion), demonstrating synergy among them. An optimal PLS model was calculated using the selected group of variables according to their importance on PLS projections (VIP). The root mean square errors of prediction (RMSEP) values of 2.9 mN m(-1) and 0.3 were estimated for interfacial tension and color, respectively. Mean relative standard deviations of 1.5% for interfacial tension and 6% for color were registered, meeting quality control requirements set by electrical energy companies. The methods proposed in this work are rapid and simple, showing great advantages over traditional approaches, which are slow and environmentally unfriendly due to chemical waste generation.

  20. Inducing magneto-electric response in topological insulator

    Zeng, Lunwu, E-mail: [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)


    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.

  1. Developmental condition and technical problems on electric insulation for super-conducting electric power machine

    Motoyama, H.


    The present situations of superconducting electric power machines in the world and studied problems were investigated from viewpoint of the electric insulation. 50MVA generator (CRIE/Hitachi) or 120MVA generator (KWU/Siemens) where the dc superconducting technique was applied on field windings, are developed. As to Superconducting transformer, 220KVA transformer is trially manufactured and the conceptual design of 1,000MVA transformer is made by W.H. or Alstom. Future problems are the study of protecting method for the overvoltage to superconducting electric power machines and the study to prevent the quench for superconducting windings. The respective insulating characteristics of solid and liquid insulators become clear gradually under the cryogenic condition but a large part of insulating characteristics of composite insulator prepared by combination of both insulators are not clear, so that these problems must be clarified.

  2. Electrically and Thermally Insulated Joint for Liquid Nitrogen Transfer

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


    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. The des......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...

  3. Self-Healable Electrical Insulation for High Voltage Applications

    Williams, Tiffany S.


    Polymeric aircraft electrical insulation normally degrades by partial discharge with increasing voltage, which causes excessive localized Joule heating in the material and ultimately leads to dielectric failure of the insulator through thermal breakdown. Developing self-healing insulation could be a viable option to mitigate permanent mechanical degradation, thus increasing the longevity of the insulation. Instead of relying on catalyst and monomer-filled microcapsules to crack, flow, and cure at the damaged sites described in well-published mechanisms, establishment of ionic crosslinks could allow for multiple healing events to occur with the added benefit of achieving full recovery strength under certain thermal environments. This could be possible if the operating temperature of the insulator is the same as or close to the temperature where ionic crosslinks are formed. Surlyn, a commercial material with ionic crosslinks, was investigated as a candidate self-healing insulator based off prior demonstrations of self-healing behavior. Thin films of varying thicknesses were investigated and the effects of thickness on the dielectric strength were evaluated and compared to representative polymer insulators. The effects of thermal conditioning on the recovery strength and healing were observed as a function of time following dielectric breakdown. Moisture absorption was also studied to determine if moisture absorption rates in Surlyn were lower than that of common polyimides.

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

    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


    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.

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

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


    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.

  6. SAFETY ALERT: Electrical insulation defect on safety helmets

    HSE Unit


    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: white yellow 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: Petzl Vertex ST Helmet (without vent) 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...

  7. Evaluation of the radiation resistance of electrical insulation materials

    Perrin, Sh.; Schönbacher, H.; Tavlet, M.; Widler, R.


    The qualification of insulating materials for electrical cables is often accomplished according to the IEC 60544 standard of the International Electrotechnical Commission. The mechanical properties of the polymeric insulators are tested prior and after irradiation at relatively high dose rates. To assess the ageing of selected materials under realistic service conditions, usually at lower dose rate, an IEC Working Group has proposed extrapolation methods (IEC 61244-2), one of which is applied here for a cable sheathing material from Huber+Suhner. The method is found to be suitable to compare radiation resistance data of different materials irradiated under different conditions.

  8. CaO insulator and Be intermetallic coatings on V-base alloys for liquid-lithium fusion blanket applications

    Park, J.H.; Kassner, T.F. [Argonne National Laboratory, Chicago, IL (United States)


    The objective of this study is to develop (a) stable CaO insulator coatings at the Liquid-Li/structural-material interface, with emphasis on electrically insulating coating that prevent adverse MHD-generated currents from passing through the V-alloy wall, and (b) stable Be-V intermetallic coating for first-wall components that face the plasma. Electrically insulating and corrosion-resistant coatings are required at the liquid-Li/structural interface in fusion first-wall/blanket application. The electrical resistance of CaO coatings produced on oxygen-enriched surface layers of V-5%Cr-5%Ti by exposing the alloy to liquid Li that contained 0.5-85 wt% dissolved Ca was measured as a function of time at temperatures between 250 and 600{degrees}C. Crack-free Be{sub 2}V intermetallic coatings were also produced by exposing V-alloys to liquid Li that contained Be as a solute. These techniques can be applied to various shapes (e.g., inside/outside of tubes, complex geometrical shapes) because the coatings are formed by liquid-phase reactions.

  9. Multifactor stress aging of electrical insulation

    Laghari, Javaid R.


    Capacitor-grade polypropylene films were aged under multiple stresses (electrical, thermal, radiation) using a 2MW thermal nuclear reactor. Thermal and electrical stresses were found to slightly decrease both the AC and DC breakdown voltages. Radiation stresses were found to increase the breakdown voltages. The same trends were seen in volume resistivity. The radiation effects dominate both the thermal and electrical effects and are attributed to increased crystallinity of the polypropylene. However, mechanical properties are significantly degraded by radiation damage, and degree of breakdown enhancements are seen for combined stresses. Computer simulation has been performed showing the magnitude of the neutrine signal from a 100 kilocurie tritium source, under the geometrical conditions of the experiments at Los Angeles National Laboratory, TA-33, is about an order of magnitude smaller than the gravity signal from a 2600 gr mass (the assumed value for the mass of the source). The observations were performed by using Professor Joe Weber's torsion balance, a room-temperature instrument.

  10. High electric field phenomena in insulation

    Laghari, J. R.; Sarjeant, W. J.


    The present study extends previous work to include electron radiation-induced changes in monoisopropyl biphenyl (MIPB)-impregnated polypropylene film as well as the effects of neutron/gamma radiation on dry polypropylene films. Effects that were quite similar were induced by both electron and neutron radiation on the properties of interest of the polypropylene films. Impregnation of the film with MIPB had a mitigatory effect on the degradation of the properties. This report also contains the results of a simultaneous electrical and thermal aging study of a capacitor-grade polypropylene film. The data obtained in this study was fitted to models that will enable realistic prediction of lifetimes under operating conditions.

  11. Fusion Energy from the electric utilities perspective: Fusion Innovation Industry Forum

    Tagle, J. A.; Felipe, A.; Gomez, A.; Sanchez-Mayoral, M. L.; Merino, A.


    The paper presents the different future energy scenarios envisaged and the so called Power Generation Fleet Transition in which Fusion Energy could play an important role. A review of the R and D and Innovation main drivers in the electric sector is outline, with a detail description of the main issues and strategic challenges in the medium and short term. The worldwide historical involvement of electric utilities in Fusion is presented and revised under the new USA Utilities technical assessment carried out by the Electric Power Research Institute EPRI. The paper also presents the work done in the last few years by the European Fusion Industry Innovation Forum FIIF-MB in order to to evaluate a wide range of fusion concepts from the utility standpoint, to enhance utilities perspective on fusion, to provide guidance to Government Bodies and national Energy strategies for fusion-utilities and finally to establish a basis for communication and cooperation in fusion for utilities standpoint. Finally the paper comments the utilities challenges pointed out by the Fusion electricity: a road map to the realization of fusion energy report issued this year by the European Fusion Development Agreement EFDA.

  12. Fusion power in a future low carbon global electricity system

    Cabal, H.; Lechón, Y.; Bustreo, C.


    Fusion is one of the technologies that may contribute to a future, low carbon, global energy supply system. In this article we investigate the role that it may play under different scenarios. The global energy model ETM (originally EFDA TIMES Model) has been used to analyse the participation...... of fusion technologies in the global electricity system in the long term. Results show that fusion technologies penetration is higher in scenarios with stricter CO2 emissions reduction targets. In addition, investment costs and discount rates of fusion technologies are key factors for fusion implementation...

  13. Designing Predictive Diagnose Method for Insulation Resistance Degradation of the Electrical Power Cables from Neutral Insulated Power Networks

    Dobra, R.; Pasculescu, D.; Risteiu, M.; Buica, G.; Jevremović, V.


    This paper describe some possibilities to minimize voltages switching-off risks from the mining power networks, in case of insulated resistance faults by using a predictive diagnose method. The cables from the neutral insulated power networks (underground mining) are designed to provide a flexible electrical connection between portable or mobile equipment and a point of supply, including main feeder cable for continuous miners, pump cable, and power supply cable. An electronic protection for insulated resistance of mining power cables can be made using this predictive strategy. The main role of electronic relays for insulation resistance degradation of the electrical power cables, from neutral insulated power networks, is to provide a permanent measurement of the insulated resistance between phases and ground, in order to switch-off voltage when the resistance value is below a standard value. The automat system of protection is able to signalize the failure and the human operator will be early informed about the switch-off power and will have time to take proper measures to fix the failure. This logic for fast and automat switch-off voltage without aprioristic announcement is suitable for the electrical installations, realizing so a protection against fires and explosion. It is presented an algorithm and an anticipative relay for insulated resistance control from three-phase low voltage installations with insulated neutral connection.

  14. Irradiation imposed degradation of the mechanical and electrical properties of electrical insulation for future accelerator magnets

    Polinski, J.; Chorowski, M.; Bogdan, P.; Strychalski, M. [Wroclaw University of Technology, Wyb. Wyspianskiego 27, 50-370 Wroclaw (Poland); Rijk, G. de [European Organization for Nuclear Research CERN, 1211 Geneva (Switzerland)


    Future accelerators will make extensive use of superconductors made of Nb{sub 3}Sn, which allows higher magnetic fields than NbTi. However, the wind-and-react technology of Nb{sub 3}Sn superconducting magnet production makes polyimide Kapton® non applicable for the coils' electrical insulation. A Nb{sub 3}Sn technology compatible insulation material should be characterized by high radiation resistivity, good thermal conductivity, and excellent mechanical properties. Candidate materials for the electrical insulation of future accelerator's magnet coils have to be radiation certified with respect to potential degradation of their electrical, thermal, and mechanical properties. This contribution presents procedures and results of tests of the electrical and mechanical properties of DGEBA epoxy + D400 hardener, which is one of the candidates for the electrical insulation of future magnets. Two test sample types have been used to determine the material degradation due to irradiation: a untreated one (unirradiated) and irradiated at 77 K with 11 kGy/min intense, 4MeV energy electrons beam to a total dose of 50 MGy.

  15. Irradiation imposed degradation of the mechanical and electrical properties of electrical insulation for future accelerator magnets

    Polinski, J.; Chorowski, M.; Bogdan, P.; Strychalski, M.; de Rijk, G.


    Future accelerators will make extensive use of superconductors made of Nb3Sn, which allows higher magnetic fields than NbTi. However, the wind-and-react technology of Nb3Sn superconducting magnet production makes polyimide Kapton® non applicable for the coils' electrical insulation. A Nb3Sn technology compatible insulation material should be characterized by high radiation resistivity, good thermal conductivity, and excellent mechanical properties. Candidate materials for the electrical insulation of future accelerator's magnet coils have to be radiation certified with respect to potential degradation of their electrical, thermal, and mechanical properties. This contribution presents procedures and results of tests of the electrical and mechanical properties of DGEBA epoxy + D400 hardener, which is one of the candidates for the electrical insulation of future magnets. Two test sample types have been used to determine the material degradation due to irradiation: a untreated one (unirradiated) and irradiated at 77 K with 11 kGy/min intense, 4MeV energy electrons beam to a total dose of 50 MGy.

  16. Heavy ion beam transport and focusing with an insulator guide in inertial confinement fusion

    Someya, T.; Nakamura, T.; Sasaki, J.; Kawata, S. [Utsunomiya Univ., Dept. of Energy and Environment Sciences, Utsunomiya, Tochigi (Japan)


    One of the key issues on the heavy ion beam inertial confinement fusion is an efficient transport and beam focusing. To get a fine focusing on the fuel pellet, neutralization of the space change of an incident beam is required. The space charge of beam has to be neutralized for the fine focusing. In this paper, we propose to employ an insulator tube guide, through which a heavy ion beam is transported and focused. We confirm that the beam space charge is effectively neutralized by electrons emitted from the insulator beam guide and the ion beam fine focusing is realized. This result shows a possibility of a good beam focusing by the insulator beam guide. (author)

  17. Electrical Probing of Inherent Spin Polarization in a Topological Insulator with Electrical Gating

    Lee, Joon Sue; Richardella, Anthony; Samarth, Nitin


    The hallmark of a time-reversal symmetry protected three-dimensional topological insulator is the helically spin-textured surface state. Although electrical detection of spin polarization in topological insulators has been demonstrated very recently, there have not been any electrical measurements to demonstrate the entire mapping of the spin polarization throughout the surface state. We report the electrical probing of the spin-polarized surface state using a magnetic tunnel junction as a spin detector while the chemical potential of a topological insulator (Bi,Sb)2Te3 is tuned by back gating. Hysteretic spin signals were observed as the magnetization of the detector ferromagnet (permalloy) switches with in-plane magnetic field. Changing the direction of bias current through the topological insulator channel flips the direction of the spin polarization, resulting in the reverse of sign of the detected spin signals. We demonstrate the control of the Fermi energy, which has importance not only in further understanding of the spin-momentum locking in the surface state but also in possible electrical tuning of the spin polarization for potential spin-based devices. Supported by C-SPIN & DARPA/SRC.


    Y.G. Gontar


    Full Text Available Results of theoretical and experimental studies of surface layer destruction in electrical insulation under lightning surge pulses are given, their impact on the insulation construction durability shown. Causes of water treeing in the surface layers of polymer insulation are analyzed.

  19. The effect of blending polypropylene on the electrical properties of polymeric insulation material Hifax



    Extensive physical testing has suggested that polymeric material Hifax (Flexible Polypropylene)could be a promising candidate for the next generation of DC insulation. In the work presented in this paper,the DC conductivity and AC breakdown of this polymeric insulation material have been measured as a function of temperature. The results show that Hifax cable insulation has a higher AC breakdown strength than EPR and XLPE (crosslinked polyethylene), and the DC resistivity of Hifax is larger than that of XLPE and oil-impregnated paper insulations. The electrical stress coefficient of resistivity of Hifax wire insulation increases with temperature, which needs to be taken into account in calculating the electrical field distribution across DC cable insulation. It has been observed that there is an anomalous change in resistivity at high electrical field, suggesting charge trapping and detrapping processes are present in Hifax cable insulation. It is concluded that blending Hifax with 62% polypropylene decreases the breakdown strength significantly.

  20. Influence of Moisture on the Electrical Properties of XLPE Insulation

    Mecheri, Yacine; Nedjar, Mohamed; Lamure, Alain; Aufray, Maëlenn; Drouet, Christophe


    International audience; During their operating service, insulated power cables can be exposed to wet environment. The presence of moisture in cables surroundings may affect the properties of the used insulation material for instance, XLPE widely employed in MV and HV power cables insulation and therefore the reliability of the insulated cables. In order to examine the influence of wet aging conditions on the performances of XLPE insulated cables,samples (plates moulded from granules HFDE 4201...

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

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


    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.)

  2. Multicharged ion-induced emission from metal- and insulator surfaces related to magnetic fusion research

    Winter, H.P. [Technische Univ., Vienna (Austria). Inst. fuer Allgemeine Physik


    The edge region of magnetically confined plasmas in thermonuclear fusion experiments couples the hot plasma core with the cold first wall. We consider the dependence of plasma-wall interaction processes on edge plasma properties, with particular emphasis on the role of slow multicharged ions (MCI). After a short survey on the physics of slow MCI-surface interaction we discuss recent extensive studies on MCI-induced electron emission from clean metal surfaces conducted at impact velocities << 1 a.u., from which generally reliable total electron yields can be obtained. We then demonstrate the essentially different role of the MCI charge for electron emission from metallic and insulator surfaces, respectively. Furthermore, we present recent results on slow MCI-induced `potential sputtering` of insulators which, in contrast to the well established kinetic sputtering, already occurs at very low ion impact energy and strongly increases with the MCI charge state. (J.P.N.). 55 refs.

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

    Diesendorf, W


    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

  4. Research on High Temperature Ceramic Insulation for Electrical Conductors

    Kreidler, Eric R.; Bhallamudi, Vidya Praveen


    Three methods for applying ceramic coatings to wires were examined in depth and a fourth (chemical vapor deposition) was studied briefly. CVD coatings were not reported in the thesis because it was realized early in the study that the deposition rate of the coatings was too slow to be used in a commercial process. Of the methods reported in the thesis, slurry coating was the most promising. This method consists of slowly drawing a platinum wire through a thixotropic slurry of alumina in a vehicle composed of polyvinyl butyral, methyl ethyl ketone, and toluene. The coatings produced by this method were continuous and free of cracks after sintering. The sintered coatings crack when the wire is bent around sharp corners, but most of the coating remains in place and still provides electrical insulation between the wire and any metallic structure to which the wire may be attached. The coating thickness was 0.61 mm (16 micrometers). The electrical resistivity of the intact coating was 340 M-Ohm-cm at 800 C and 23 M-Ohm-cm at 1050 C. Therefore, these coatings more than meet the electrical requirements for use in turbine engines. Although adherence of the coating to the wire was generally excellent, a problem was noted in localized areas where the coating flaked off. Further work will be needed to obtain good coating adherence along the entire length of the wire. The next most promising coatings were made by electrophoretic deposition (EPD) of Al2O3 onto platinum wires, using mixtures of ethanol and acetone as the suspending liquid. These EPD coatings were made only on short lengths of wire because the coating is too fragile to allow spooling of the wire. The worst coatings were those made by electrophoretic deposition from aqueous suspensions. Continuous slurry coating of wire was achieved, but due to lack of suitable equipment, the wire had to be cut into short lengths for sintering.

  5. Heat transfer in electrical insulation of LHC cables cooled with superfluid helium

    Meuris, C; Leroy, D; Szeless, Balázs


    The electrical insulation of the Large Hadron Collider (LHC) cables constitutes a thermal barrier between the conductor and the superfluid helium bath. This can prevent removal of the heat dissipated in the cable by the current rise in the dipoles or by the beam losses. The main experimental results, obtained with stacks of insulated conductors representing a piece of the actual coil, are given. The mock-ups vary only by the material composition and the structure of the electrical insulation. Analysis of the temperature distribution measured in the conductors as a function of the dissipated heat power makes it possible to determine the dominant heat transfer mode in each type of tested insulation and to classify these according to their permeability to superfluid helium. Thermal numerical modelling of the experimental mock-ups clarifies the heat transfer path in the complex structure of the insulation and enables calculation of values of the thermal quantities characteristic of each insulation. The results of...

  6. Insulator

    Nakajima, Isao; Ikami, Toshiichi.


    The insulating properties of transmission line insulators are reduced when the insulator becomes contaminated. Such contamination is promoted by the adherence of rainwater including dusts and/or absorbing of dusts and gas when the insulated surface is wetted with rainwater. It is known to treat insulators with water repellent compounds to avoid this problem, but known treatments have certain disadvantages such as loss of water repellency in a short time. An object of this invention is to overcome these disadvantages and to provide an insulator having a high usefulness and excellent water repellency which can be easily treated and maintained over a long period of time. It has been found that if a glass layer itself forming the surface of the insulator has water repellent properties, the water repellency of the insulator surface is not lost. According to the invention, the glassy surface is treated with silane or silazane to provide a surface layer of the proper water repellency. The insulator surface may be preferably treated in such a manner that the insulator is immersed in a bath of silane or silazane. Experiments are described to illustrate the performance of insulators treated according to the invention in comparison to non-treated insulators. 1 fig., 1 tab.

  7. Electrical performance of distribution insulators with chlorella vulgaris growth on its surface

    H. E. Rojas


    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%.

  8. Three-dimensional machining of insulating ceramics materials with electrical discharge machining

    Yasushi FUKUZAWA; Naotake MOHRI; Hiromitsu GOTOH; Takayuki TANI


    The insulating ceramics were processed with sinking and wire cut electrical discharge machining(EDM). The new technology was named as the assisting electrode method. In the machining, the electrical conductive material was adhered on the surface of insulating workpiece as the starting point of electrical discharge. As the processing operated in oil, the electrical conductive product composed of decomposition carbon element from working oil adhered on the workpiece during discharge. The discharges generated continuously with the formation of the electrical conductive layer. So, the insulating ceramics turn to the machinable material by EDM. We introduced the mechanism and the application of the machining of insulating ceramics such as Si3N4 and ZrO2.

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

    Issouf Fofana


    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.

  10. Electrical breakdown strength results from the EU testing program for potential ITER insulation

    Broadbent, A.J.; Crozier, J.; Smith, K.D. [Oxford Instruments, Oxon (United Kingdom)] [and others


    Insulation systems will be a key element in the future construction and impregnation of the coils for the ITER device. Electrical barrier layers have been specified to improve the electrical reliability, and this program includes ceramic plasma sprayed coatings, Kapton, Nomex and Mica in conjunction with various Epoxy resins. The electrical breakdown strengths in liquid nitrogen of twenty-two different insulation systems are reported. The final results of this program are presented and compared with the results from a benchmark testing program (insulation system based on anhydride cured DGEBA resin and S2 glass).

  11. Effect of pollutant gases on electrical insulators deterioration

    Zamarad, A.


    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.

  12. Development of electrically insulating CaO coatings

    Natesan, K.; Reed, C.B.; Uz, M.; Rink, D.L. [Argonne National Lab., IL (United States)


    A systematic study has been initiated to develop electrically insulating CaO coatings by vapor phase transport and by in-situ formation in a liquid Li environment. Several experiments were conducted in vapor transport studies with variations in process temperature, time, specimen location, specimen surface preparation, and pretreatment. Several of the coatings obtained by the method exhibited Ca concentration in the range of 60--95 wt.% on the surface. However, coating thickness has not been very uniform among several samples exposed in the same run or even within the same sample. The coatings developed in these early tests degraded after 24 h exposure to Li at 500 C. Additional experiments are underway to develop better-adhering and more dense coatings by this method. A program to develop in-situ CaO coatings in Li has been initiated, and the first set of capsule tests at 800 C in three different Li-Ca mixtures will be completed in early July. Specimens included in the run are bare V-4Cr-4Ti alloy, specimens with a grit-blasted surface and O-precharged in 99.999% Ar, polished specimens precharged in a 99.999% Ar and 5000 ppm O{sub 2}-N{sub 2} mixture, and prealuminized V-5Cr-5Ti alloy preoxidized in a 5000 ppm O{sub 2}-N{sub 2} mixture. Additional experiments at lower temperatures are planned.

  13. Robust Mechanical Properties of Electrically Insulative Alumina Films by Supersonic Aerosol Deposition

    Lee, Jong-Gun; Cha, You-Hong; Kim, Do-Yeon; Lee, Jong-Hyuk; Lee, Tae-Kyu; Kim, Woo-Young; Park, Jieun; Lee, Dongyun; James, Scott C.; Al-Deyab, Salem S.; Yoon, Sam S.


    Electrically insulating alumina films were fabricated on steel substrates using supersonic aerosol deposition and their hardness and scratchability were measured. Alumina particles (0.4-μm diameter) were supersonically sprayed inside a low-pressure chamber using between 1 and 20 nozzle passes. These alumina particles were annealed between 300 and 800 K to determine the temperature's effect on film crystal size (37-41 nm). Smoother surface morphology and increased electrical resistance of the thin films were observed as their thicknesses grew by increasing the number of passes. Resistances of up to 10,000 MΩ demonstrate robust electrical insulation. Significant hardness was measured (1232 hv or 13.33 GPa), but the alumina films could be peeled off with normal loads of 36 and 47 N for films deposited on stainless steel and SKD11 substrates, respectively. High insulation and hardness confirm that these alumina films would make excellent electrical insulators.

  14. Study on the Microscopic Figures of Power Transformer Insulation Paper Under Electrical and Thermal Stresses

    Liao, Rui-Jin; Tang, Chao; Yang, Li-Jun

    In this paper, Atomic Force Microscope (AFM) was used to observe the microscopic figure of aged insulation paper in order to analyze the microscopic ageing mechanism of power transformer insulation paper under electrical and thermal stresses. The results indicate that there are obvious concaves and convexes on the surface of aged insulation paper, and the paper samples are punctured because of chain scission and the flow of discharge current, which destroyed the compact cellulose chains structures and the diameter of punctures is about 0.5 nm. In addition, this paper analyzed the influence to the physical chemistry characteristics of insulation paper caused by partial discharge and paper ageing.

  15. Comparison of Dissolved Gases in Mineral and Vegetable Insulating Oils under Typical Electrical and Thermal Faults

    Chenmeng Xiang


    Full Text Available Dissolved gas analysis (DGA is attracting greater and greater interest from researchers as a fault diagnostic tool for power transformers filled with vegetable insulating oils. This paper presents experimental results of dissolved gases in insulating oils under typical electrical and thermal faults in transformers. The tests covered three types of insulating oils, including two types of vegetable oil, which are camellia insulating oil, Envirotemp FR3, and a type of mineral insulating oil, to simulate thermal faults in oils from 90 °C to 800 °C and electrical faults including breakdown and partial discharges in oils. The experimental results reveal that the content and proportion of dissolved gases in different types of insulating oils under the same fault condition are different, especially under thermal faults due to the obvious differences of their chemical compositions. Four different classic diagnosis methods were applied: ratio method, graphic method, and Duval’s triangle and Duval’s pentagon method. These confirmed that the diagnosis methods developed for mineral oil were not fully appropriate for diagnosis of electrical and thermal faults in vegetable insulating oils and needs some modification. Therefore, some modification aiming at different types of vegetable oils based on Duval Triangle 3 were proposed in this paper and obtained a good diagnostic result. Furthermore, gas formation mechanisms of different types of vegetable insulating oils under thermal stress are interpreted by means of unimolecular pyrolysis simulation and reaction enthalpies calculation.

  16. Dielectric and electrical design consideration of ceramics for fusion devices

    Ohno, H.


    The research and development of high performance ceramics for nuclear applications are increasing their importance. Especially in nuclear development, innovative and application of ceramics are needed in fusion reactors. Summarized are the development of new materials such as silicon nitride with good mechanical and electrical properties and the application of zirconia-based ceramics for high temperature electrolysis of tritiated water in a tritium recycling system.

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

    Pilan, N., E-mail: [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)


    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.

  18. High Temperature Electrical Insulation Materials for Space Applications Project

    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...

  19. Automatic extraction of insulators from 3D LiDAR data of an electrical substation

    Arastounia, M.; Lichti, D. D.


    A considerable percentage of power outages are caused by animals that come into contact with conductive elements of electrical substations. These can be prevented by insulating conductive electrical objects, for which a 3D as-built plan of the substation is crucial. This research aims to create such a 3D as-built plan using terrestrial LiDAR data while in this paper the aim is to extract insulators, which are key objects in electrical substations. This paper proposes a segmentation method based on a new approach of finding the principle direction of points' distribution. This is done by forming and analysing the distribution matrix whose elements are the range of points in 9 different directions in 3D space. Comparison of the computational performance of our method with PCA (principal component analysis) shows that our approach is 25% faster since it utilizes zero-order moments while PCA computes the first- and second-order moments, which is more time-consuming. A knowledge-based approach has been developed to automatically recognize points on insulators. The method utilizes known insulator properties such as diameter and the number and the spacing of their rings. The results achieved indicate that 24 out of 27 insulators could be recognized while the 3 un-recognized ones were highly occluded. Check point analysis was performed by manually cropping all points on insulators. The results of check point analysis show that the accuracy, precision and recall of insulator recognition are 98%, 86% and 81%, respectively. It is concluded that automatic object extraction from electrical substations using only LiDAR data is not only possible but also promising. Moreover, our developed approach to determine the directional distribution of points is computationally more efficient for segmentation of objects in electrical substations compared to PCA. Finally our knowledge-based method is promising to recognize points on electrical objects as it was successfully applied for

  20. Development of design technique for vacuum insulation in large size multi-aperture multi-grid accelerator for nuclear fusion

    Kojima, A.; Hanada, M.; Tobari, H.; Nishikiori, R.; Hiratsuka, J.; Kashiwagi, M.; Umeda, N.; Yoshida, M.; Ichikawa, M.; Watanabe, K.; Yamano, Y.; Grisham, L. R.


    Design techniques for the vacuum insulation have been developed in order to realize a reliable voltage holding capability of multi-aperture multi-grid (MAMuG) accelerators for fusion application. In this method, the nested multi-stage configuration of the MAMuG accelerator can be uniquely designed to satisfy the target voltage within given boundary conditions. The evaluation of the voltage holding capabilities of each acceleration stages was based on the previous experimental results about the area effect and the multi-aperture effect. Since the multi-grid effect was found to be the extension of the area effect by the total facing area this time, the total voltage holding capability of the multi-stage can be estimated from that per single stage by assuming the stage with the highest electric field, the total facing area, and the total apertures. By applying these consideration, the analysis on the 3-stage MAMuG accelerator for JT-60SA agreed well with the past gap-scan experiments with an accuracy of less than 10% variation, which demonstrated the high reliability to design MAMuG accelerators and also multi-stage high voltage bushings.

  1. Development of design technique for vacuum insulation in large size multi-aperture multi-grid accelerator for nuclear fusion

    Kojima, A., E-mail:; Hanada, M.; Tobari, H.; Nishikiori, R.; Hiratsuka, J.; Kashiwagi, M.; Umeda, N.; Yoshida, M.; Ichikawa, M.; Watanabe, K. [Japan Atomic Energy Agency, Naka, Ibaraki 311-0193 (Japan); Yamano, Y. [Saitama University, Saitama, Saitama-ken 338-8570 (Japan); Grisham, L. R. [Princeton Plasma Physics Laboratory, Princeton, New Jersey 08543 (United States)


    Design techniques for the vacuum insulation have been developed in order to realize a reliable voltage holding capability of multi-aperture multi-grid (MAMuG) accelerators for fusion application. In this method, the nested multi-stage configuration of the MAMuG accelerator can be uniquely designed to satisfy the target voltage within given boundary conditions. The evaluation of the voltage holding capabilities of each acceleration stages was based on the previous experimental results about the area effect and the multi-aperture effect. Since the multi-grid effect was found to be the extension of the area effect by the total facing area this time, the total voltage holding capability of the multi-stage can be estimated from that per single stage by assuming the stage with the highest electric field, the total facing area, and the total apertures. By applying these consideration, the analysis on the 3-stage MAMuG accelerator for JT-60SA agreed well with the past gap-scan experiments with an accuracy of less than 10% variation, which demonstrated the high reliability to design MAMuG accelerators and also multi-stage high voltage bushings.

  2. Development of design technique for vacuum insulation in large size multi-aperture multi-grid accelerator for nuclear fusion.

    Kojima, A; Hanada, M; Tobari, H; Nishikiori, R; Hiratsuka, J; Kashiwagi, M; Umeda, N; Yoshida, M; Ichikawa, M; Watanabe, K; Yamano, Y; Grisham, L R


    Design techniques for the vacuum insulation have been developed in order to realize a reliable voltage holding capability of multi-aperture multi-grid (MAMuG) accelerators for fusion application. In this method, the nested multi-stage configuration of the MAMuG accelerator can be uniquely designed to satisfy the target voltage within given boundary conditions. The evaluation of the voltage holding capabilities of each acceleration stages was based on the previous experimental results about the area effect and the multi-aperture effect. Since the multi-grid effect was found to be the extension of the area effect by the total facing area this time, the total voltage holding capability of the multi-stage can be estimated from that per single stage by assuming the stage with the highest electric field, the total facing area, and the total apertures. By applying these consideration, the analysis on the 3-stage MAMuG accelerator for JT-60SA agreed well with the past gap-scan experiments with an accuracy of less than 10% variation, which demonstrated the high reliability to design MAMuG accelerators and also multi-stage high voltage bushings.

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

    Milan Spohner


    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.

  4. Electrical and Mechanical Performance of an Enhanced Cable Insulation Scheme for Superconducting Magnets

    Fessia, P; Luzieux, S; Tommasini, D; Gerardin, A; Guinchard, M; Regis, F; Sgobba, S; Zaghloul, A


    New polyimide cable insulation schemes improving the cooling of Nb-Ti superconducting coils were recently developed to face the severe heat loads at which the next generation of superconducting accelerator magnets will work. In order to qualify the new insulation, a test campaign was realized to assess both its electrical and mechanical features with respect to the standard LHC insulation. The electrical tests assessed the dielectric strength and inter-turn leakage current to be satisfactory. The mechanical tests investigated the insulation thickness under load and the stress relaxation at ambient temperature, thus providing essential information for the magnetic and mechanical design of the final focusing magnets for the LHC upgrade phase I.

  5. Factors determining cost and quality of the electrical insulation in the VPI-process

    Bruetsch, R.; Allison, J.; Thaler, T. [Von Roll Isola, Breitenbach (Switzerland)


    The construction of the electrical insulation and the carrying out of the VPI-process are critical steps in the production of rotating high voltage machines. On the other hand the manufacture of the insulation and the VPI-process are cost factors. It is therefore important to know the factors influencing cost and quality of the insulation in the VPI-process in order to determine the optimal production parameters and to achieve a high reliability of the resulting machine. This article gives an overview of the relevant factors and some considerations regarding costs.

  6. Mathematical Model of Lifetime Duration at Insulation of Electrical Machines

    Mihaela Răduca


    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.

  7. Electrical conduction mechanism in bulk ceramic insulators at high voltages until dielectric breakdown

    Neusel, C.; Jelitto, H.; Schneider, G. A.


    In order to develop and verify a dielectric breakdown model for bulk insulators thicker than 100 μm, the knowledge of the dominating conduction mechanism at high electric fields, or respectively voltages, is necessary. The dielectric breakdown is the electrical failure of an insulator. In some existing breakdown models, ohmic conduction is assumed as dominating conduction mechanism. For verification, the dominating dc conduction mechanism of bulk insulators at room temperature was investigated by applying high voltages up to 70 kV to the insulator until dielectric breakdown occurs. Four conduction models, namely, ohmic, space charge limited, Schottky, and Poole-Frenkel conduction, were employed to identify the dominating conduction mechanism. Comparing the calculated permittivities from the Schottky and Poole-Frenkel coefficients with experimentally measured permittivity, Schottky and Poole-Frenkel conduction can be excluded as dominating conduction mechanism. Based on the current density voltage characteristics (J-V-curve) and the thickness-dependence of the current density, space charge limited conduction (SCLC) was identified to be the dominating conduction mechanism at high voltages leading to dielectric breakdown. As a consequence, breakdown models based on ohmic conduction are not appropriate to explain the breakdown of the investigated bulk insulators. Furthermore, the electrical failure of the examined bulk insulators can only be described correctly by a breakdown model which includes SCLC as conduction mechanism.

  8. Investigation of electrical characteristics of no-insulation coil wound with surface-processed HTS tape

    Jeon, Haeryong; Lee, Woo Seung; Kim, Jinsub; Baek, Geonwoo; Jeon, Sangsu; Yoon, Yong Soo; Ko, Tae Kuk


    This paper deals with the electrical characteristics of no-insulation coil wound with surface-processed HTS tape. The bypassing current path through turn-to-turn contacts within a coil is formed in the no-insulation coil, and this bypassing current path determines two characteristics: 1) self-protection and 2) charge-discharge delay. The amplitude of bypassing current is determined by contact resistance between the turn-to-turn contacts of the no-insulation coil. The surface roughness of the HTS tape is one of the parameters to change the contact resistance. The HTS tapes were processed to roughen by bead blast and abrasive paper, and the no-insulation coil is fabricated using processed HTS tape. We have studied the charge-discharge delay and self-protecting characteristic of each no-insulation coil by 1) sudden discharge tests and 2) overcurrent tests. The FEM simulations of contact resistance of no-insulation coil were carried out. The contact surface resistance of a case processed by abrasive paper has almost three times larger than that of reference no-insulation coil, and a case processed by bead blast presents almost same contact surface resistance with reference no-insulation coil.

  9. A Novel Method for Measuring Electrical Conductivity of High Insulating Oil Using Charge Decay

    Wang, Z. Q.; Qi, P.; Wang, D. S.; Wang, Y. D.; Zhou, W.


    For the high insulating oil, it is difficult to measure the conductivity precisely using voltammetry method. A high-precision measurementis proposed for measuring bulk electrical conductivity of high insulating oils (about 10-9--10-15S/m) using charge decay. The oil is insulated and charged firstly, and then grounded fully. During the experimental procedure, charge decay is observed to show an exponential law according to "Ohm" theory. The data of time dependence of charge density is automatically recorded using an ADAS and a computer. Relaxation time constant is fitted from the data using Gnuplot software. The electrical conductivity is calculated using relaxation time constant and dielectric permittivity. Charge density is substituted by electric potential, considering charge density is difficult to measure. The conductivity of five kinds of oils is measured. Using this method, the conductivity of diesel oil is easily measured to beas low as 0.961 pS/m, as shown in Fig. 5.

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

    Lizzit, Silvano; Larciprete, Rosanna; Lacovig, Paolo


    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 ......, 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.......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...

  11. Non-electric applications for magneto-inertial fusion

    Slough, John


    In addition to the generation of commercial electric power, there are several other applications for an intense pulse of neutrons that would be produced by magneto-inertial fusion (MIF) systems. Many of these applications can be achieved without the need for a fully developed reactor at high gain, and could thus be pursued at a much earlier stage of development which would dramatically reduce the risk of the long-term development and concern for the expense of an all-encompassing, single use system such as the tokamak or stellerator. A short list of applications well suited for MIF would include: (1) production of radioisotopes for medical applications and research, (2) efficient, high power propulsion through direct fusion heating of lithium propellants (3) Noninvasive interrogation of objects for homeland security (4) neutron radiography and tomography (5) destruction of long-lived radioactive waste, and (6) breeding of proliferation proof fissile fuel for existing nuclear reactors. These applications could all be pursued at lower neutron yield, but clearly the energy goals are by far the most significant and far reaching such as applying fusion energy as a hybrid to enable thorium cycle reactors which produce very little waste compared to the current uranium reactors. A discussion of how MIF could be configured and utilized to realize several of these uses will be discussed.

  12. Leakage current measurement of protective equipment insulating materials used in electrical installations

    Buică, G.; Dobra, R.; Păsculescu, D.; Tătar, A.


    This research describes the behaviour of equipment and safety devices during use in extreme environmental conditions, in order to establish the technical conditions and additional health and safety requirements during operation, to ensure the health and safety of users, regardless of conditions and working environment in which they are use. The studies have been conducted both on new equipment and means of protection used in electrical installations. There has been evaluated protective equipment made of insulating rubber, reinforced fiberglass or PVC. They have been followed the technical characteristics and protection against electric shock by measuring the leakage current of different insulating materials.

  13. Investigations of the electrical breakdown properties of insulator materials used in high voltage vacuum diodes

    Shurter, R.P.; Carlson, R.L.; Melton, J.G.


    The Injector for the proposed Dual-Axis Radiographic Hydrodynamic Testing (DARHT) Facility at Los Alamos utilizes a monolithic insulator deployed in a radial configuration. The 1.83-m-diam {times} 25.4-cm-thick insulator with embedded grading rings separates the output oil transmission line from the vacuum vessel that contains the re-entrant anode and cathode assemblies. Although much work has been done by the pulse power community in studying surface flash-over of insulating materials used in both axial and radial configurations, dendrite growth at the roots of grading rings embedded in materials suitable for very large insulators is less well characterized. Degradation of several acrylic insulators has been observed in the form of dendrites growing at the roots of the grading rings for large numbers (100`s) of pulses on the prototype DARHT Injector and other machines using similar radial geometries. In a few cases, these dendrites have led to catastrophic bulk breakdown of the acrylic between two grading rings making the insulator a costly loss. Insulating materials under investigation are acrylic (Lucite), epoxy (Furane), and cross-linked polystyrene (Rexolite); each of these materials has its own particular mechanical and electrical merits. All of these materials have been cast and machined into the required large size for the Injector. Test methods and the results of investigations into the breakdown strength of various interface geometries and the susceptibility of these materials to dendrite growth are reported.

  14. Doping Effect of Graphene Nanoplatelets on Electrical Insulation Properties of Polyethylene: From Macroscopic to Molecular Scale

    Ziang Jing


    Full Text Available The doping effect of graphene nanoplatelets (GNPs on electrical insulation properties of polyethylene (PE was studied by combining experimental and theoretical methods. The electric conduction properties and trap characteristics were tested for pure PE and PE/GNPs composites by using a direct measurement method and a thermal stimulated current (TSC method. It was found that doping smaller GNPs is more beneficial to decrease the conductivity of PE/GNPs. The PE/GNPs composite with smaller size GNPs mainly introduces deep energy traps, while with increasing GNPs size, besides deep energy traps, shallow energy traps are also introduced. These results were also confirmed by density functional theory (DFT and the non-equilibrium Green’s function (NEGF method calculations. Therefore, doping small size GNPs is favorable for trapping charge carriers and enhancing insulation ability, which is suggested as an effective strategy in exploring powerful insulation materials.

  15. Electrical conductivity induced in insulators by pulsed radiation

    Ahrens, T.J.; Wooten, F.


    The minimum prompt photoconductivity induced by pulses of x rays, gamma rays, and energetic electrons in various amorphous and disordered insulating organic and inorganic materials is predicted on the basis of data for the scattering of hot electrons in solids and the band gap for insulators. For total doses of 3 x 10/sup 4/ to 30 x 10/sup 4/ rad or greater, the minimum prompt photoconductivity is predicted to be linear with dose rate, ..gamma.., and is given by sigma(..cap omega../sup -1/cm/sup -1/) = 5 x 10/sup -19/ rho/sub 0/..gamma../E/sup 2//sub g/, where rho/sub 0/ is the density (g/cm/sup 3/) and E/sub g/ is the optical band gap (eV). This formula agrees well with data for a variety of plastics, mica, and borosilicate glass under widely different irradiation conditions. The formula considerably underestimates absolute values of prompt conductivities observed for Al/sub 2/O/sub 3/, MgO, and certain plastics, because the model does not hold for ordered materials.

  16. Analysis of electrical tree propagation in XLPE power cable insulation

    Bao Minghui, E-mail: [College of Electrical and Electronic Engineering, Huazhong University of Science and Technology, Wuhan (China); Yin Xiaogen; He Junjia [College of Electrical and Electronic Engineering, Huazhong University of Science and Technology, Wuhan (China)


    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.

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

    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)


    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)

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

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


    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.


    I. V. Oleksyuk


    Full Text Available Electrical power cables with Cross-Linked Polyethylene Insulation (XLPE-insulation are currently utilized in projects of the electric-power supply systems of modern facilities. However, the higher costs, the incomplete design, installation and maintenance normativetechnical basis as well as certain constructional features of the XLPE-insulated cable lines hinder their large-scale implementation.The cables with XLPE insulation are mostly produced in a single-conductor core version being provided with a composite copper shield whose cross-section may vary while the electric conductor cross-section remains uniform. Earthing the cable shields on both sides causes the flow of electricity in them. The course of operational service of the XLPE-insulated cable lines revealed the following fact – the currents induced in the cable shields can run up to the levels commeasurable with those in the conductor-cores themselves. That, in its turn, leads to electrical safety-level reduction, cable lines failure, and economic losses. The currents induced in the shields may occur both in symmetric (normal and emergency and asymmetric operating modes of the power grid with values of the induced currents reaching 80 % of the conducting core currents. Many factors affect the level of the current induced in the shield: the midpoint conductor modes, the values of the core longitudinal currents in the normal and emergency operating modes, failure mode, the cross-section area of the shield, the cables mutual disposition, and the distance between them.The paper claims experimental existence conformation of the cable-shield current induced by that in the conductor-core and demonstrates its measured value. The author establishes that induction of dangerous currents in the cable shields demands elaboration of measures on reducing their level.

  20. Intelligent Video Surveillance for Detecting Snow and Ice Coverage on Electrical Insulators of Power Transmission Lines

    Gu, Irene Y. H.; Sistiaga, Unai; Berlijn, Sonja M.; Fahlström, Anders

    One of the problems for electrical power delivery through power lines in northern countries is when snow or ice accumulates on electrical insulators. This could lead to snow or ice-induced outages and voltage collapse, causing huge economic loss. This paper proposes a novel real-time intelligent surveillance and image analysis system for detecting and estimating the snow and ice coverage on electric insulators using images captured from an outdoor 420 kV power transmission line. In addition, the swing angle of insulators is estimated, as large swing angles due to wind cause short circuits. Hybrid techniques by combining histogram, edges, boundaries and cross-correlations are employed for handling a broad range of scenarios caused by changing weather and lighting conditions. Experiments have been conducted on the captured images over several month periods. Results have shown that the proposed system has provided valuable estimation results. For image pixels related to snows on the insulator, the current system has yielded an average detection rate of 93% for good quality images, and 67.6% for images containing large amount of poor quality ones, and the corresponding average false alarm ranges from 9% to 18.1%. Further improvement may be achieved by using video-based analysis and improved camera settings.

  1. Semiconductor structures having electrically insulating and conducting portions formed from an AlSb-alloy layer

    Spahn, Olga B.; Lear, Kevin L.


    A semiconductor structure. The semiconductor structure comprises a plurality of semiconductor layers formed on a substrate including at least one layer of a III-V compound semiconductor alloy comprising aluminum (Al) and antimony (Sb), with at least a part of the AlSb-alloy layer being chemically converted by an oxidation process to form superposed electrically insulating and electrically conducting portions. The electrically insulating portion formed from the AlSb-alloy layer comprises an oxide of aluminum (e.g. Al.sub.2 O.sub.3), while the electrically conducting portion comprises Sb. A lateral oxidation process allows formation of the superposed insulating and conducting portions below monocrystalline semiconductor layers for forming many different types of semiconductor structures having particular utility for optoelectronic devices such as light-emitting diodes, edge-emitting lasers, vertical-cavity surface-emitting lasers, photodetectors and optical modulators (waveguide and surface normal), and for electronic devices such as heterojunction bipolar transistors, field-effect transistors and quantum-effect devices. The invention is expected to be particularly useful for forming light-emitting devices for use in the 1.3-1.6 .mu.m wavelength range, with the AlSb-alloy layer acting to define an active region of the device and to effectively channel an electrical current therein for efficient light generation.

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

    N. Davari


    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.

  3. Polarizing Oxygen Vacancies in Insulating Metal Oxides under a High Electric Field

    Youssef, Mostafa; Van Vliet, Krystyn J.; Yildiz, Bilge


    We demonstrate a thermodynamic formulation to quantify defect formation energetics in an insulator under a high electric field. As a model system, we analyzed neutral oxygen vacancies (color centers) in alkaline-earth-metal binary oxides using density functional theory, Berry phase calculations, and maximally localized Wannier functions. The work of polarization lowers the field-dependent electric Gibbs energy of formation of this defect. This is attributed mainly to the ease of polarizing the two electrons trapped in the vacant site, and secondarily to the defect induced reduction in bond stiffness and softening of phonon modes. The formulation and analysis have implications for understanding the behavior of insulating oxides in electronic, magnetic, catalytic, and electrocaloric devices under a high electric field.

  4. Electrical Insulation Of Carbon Nanotube Separation Columns For Microchip Electrochromatography

    Mogensen, Klaus Bo; Chen, Miaoxiang Max; Mølhave, Kristian


    Carbon nanotubes (CNT) have been grown in microfluidic glass channels for chemical analysis based on electrokinetic separations. A limitation of CNTs for this type of application is their high conductivity, which prevent them from being used for electroosmotic pumping with electrical field...

  5. Electrical Insulation Of Carbon Nanotube Separation Columns For Microchip Electrochromatography

    Mogensen, Klaus Bo; Chen, Miaoxiang Max; Mølhave, Kristian


    Carbon nanotubes (CNT) have been grown in microfluidic glass channels for chemical analysis based on electrokinetic separations. A limitation of CNTs for this type of application is their high conductivity, which prevent them from being used for electroosmotic pumping with electrical field...

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

    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)


    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.

  7. Heat transfer through Rutherford superconducting cable with novel pattern of polyimide electrical insulation in pressurized superfluid helium environment

    Chorowski, Maciej; Polinski, Jaroslaw; Strychalski, Michal


    Future LHC accelerator luminosity upgrade will increase a beam losses heat deposition in the superconducting magnet coils. Main barrier of the heat evacuation from the coils made of Rutherford type cables is a cable electrical insulation. The insulation is made of polyimide tapes wrapped around the cable in a special configuration. Presently used insulation wrapping schemes constitute very good electrical insulation with relatively low heat transport ability. Therefore a new insulation wrapping schemes with enhanced helium permeability and adequate dielectric properties have been developed at CERN. An experimental comparative study of heat transfer perpendicular to the Rutherford type cable, for an old and new insulation wrapping schemes have been accomplished at Wroclaw University of Technology. The tests have been performed in pressurized superfluid helium conditions, and at 60 MPa of the sample applied external pressure simulating the Lorentz forces. This paper presents the measurements methodology and gives experimental results.

  8. Electric field-induced superconducting transition of insulating FeSe thin film at 35 K.

    Hanzawa, Kota; Sato, Hikaru; Hiramatsu, Hidenori; Kamiya, Toshio; Hosono, Hideo


    It is thought that strong electron correlation in an insulating parent phase would enhance a critical temperature (Tc) of superconductivity in a doped phase via enhancement of the binding energy of a Cooper pair as known in high-Tc cuprates. To induce a superconductor transition in an insulating phase, injection of a high density of carriers is needed (e.g., by impurity doping). An electric double-layer transistor (EDLT) with an ionic liquid gate insulator enables such a field-induced transition to be investigated and is expected to result in a high Tc because it is free from deterioration in structure and carrier transport that are in general caused by conventional carrier doping (e.g., chemical substitution). Here, for insulating epitaxial thin films (∼10 nm thick) of FeSe, we report a high Tc of 35 K, which is 4× higher than that of bulk FeSe, using an EDLT under application of a gate bias of +5.5 V. Hall effect measurements under the gate bias suggest that highly accumulated electron carrier in the channel, whose area density is estimated to be 1.4 × 10(15) cm(-2) (the average volume density of 1.7 × 10(21) cm(-3)), is the origin of the high-Tc superconductivity. This result demonstrates that EDLTs are useful tools to explore the ultimate Tc for insulating parent materials.

  9. Electric field measurement on time domain generated by corona on insulators on distribution systems

    Frota Mattos, M.A. da; Biagioni, P.H.; Bassi, W. [Univ. of Sao Paulo (Brazil). Inst. de Electrotecnica e Energia


    Radio interference and TV interference are being a problem in urban and rural areas. This interference is generated by high voltage transmission lines as well as distribution lines. The radio noise can be produced by polluted or damaged insulators, and by metal parts of the distribution lines. The corona effect on the surface of the dielectric material produces high frequency electromagnetic fields during the ionization and during the recombination period. Fields of different intensity are produced by positive voltage and negative voltage. The insulator flashover (leaking current) also produces electromagnetic fields. A new technique to measure these fields was developed. This technique measures the radiated fields on time domain and on frequency domain. This permits us to characterize the radiated field and thus identify the type of the source. Several measurements were done varying the type of the RF generator, i.e., new insulator and broken insulator. A digitizing oscilloscope was used to observe the electric field on a monopole antenna and the ac voltage applied to the insulator.

  10. Fabrication of aligned nanofibers by electric-field-controlled electrospinning: insulating-block method

    Hwang, Wontae; Pang, Changhyun; Chae, Heeyeop


    Aligned nanofiber arrays and mats were fabricated with an electrospinning process by manipulating the electric field. The electric field was modified by insulating blocks (IBs) that were installed between the nozzle and the substrate as guiding elements to control the trajectory of the electrospinning jet flow. Simulation results showed that the electric field was deformed near the IBs, resulting in confinement of the electrospinning jet between the blocks. The balance of the electric field in the vertical direction and the repulsive force by space charges in the confined electrified jet stream was attributed to the aligned motion of the jet. Aligned arrays of 200 nm thick polyethylene oxide nanofibers were obtained, exhibiting wave-shaped and cross patterns as well as rectilinear patterns. In addition, 40 μm thick quasi-aligned carbon-nanofiber mats with anisotropic electrical property were also attained by this method.

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

    Jin, Young Kyu


    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.

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

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


    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 an...... 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....

  13. Insulation development for high-temperature batteries for electric vehicle application. Final report



    The objective of this contract is to develop and demonstrate a high performance, vacuum insulation which is capable of withstanding 15 psi plus battery loading with low compression operating in the 660 to 840/sup 0/F range. The developed insulation would allow construction of rectangular, lightweight and low-cost, vacuum-insulated enclosures for electric vehicles using Na/S or Li/MS batteries. The goals of the program are to develop a vacuum insulation with the following properties: thermal conductivity 140 x 10/sup -5/ Btu/h-ft/sup 0/F, density, 18 lbs/ft/sup 3/ and compression 10% from 0 to 15 psi load. A new milestone in high-temperature, load-bearing, preformed insulation was achieved. The two insulation systems demonstrated to-date have exceeded the goals of the program. Pegged Multi-Foil system has a measured conductivity of 100 x 10/sup -5/ Btu/h-ft/sup 0/F between 840 and 75/sup 0/F, density 11 lbs/ft/sup 3/ and compression of 10%. The second system which exceeded the goals of the program is a Linde Multi-Foil inslation with discrete load-carrying support areas. It has a measured thermal conductivity of 95 x 10/sup -5/ Btu/h-ft/sup 0/F, a density of 15 lbs/ft/sup 3/ and a compression of 21%. A third inslation is a continuous support, load-bearing board system. Although the thermal conductivity and density are above the goal of the program, the system is very practical and may be used in specialized applications; i.e., forklift trucks. The best load-bearing board insulation system developed to-date has a conductivity of 224 x 10/sup -5/ Btu/hr-ft/sup 0/F, a density of 22 lbs/ft/sup 3/ and a compression of 7%. It is believed that the new insulation systems need further development in order to establish their long-term stability, handleability and cost-effective production.

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

    Lim, Seung Jae


    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.

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

    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:; 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)


    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)

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

    Carlos A. Ferreira


    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.

  17. Understanding Electrical Treeing Phenomena in XLPE Cable Insulation Adopting UHF Technique

    Sarathi, Ramanujam; Nandini, Arya; Danikas, Michael G.


    A major cause for failure of underground cables is due to formation of electrical trees in the cable insulation. A variety of tree structure can form from a defect site in cable insulation viz bush-type trees, tree-like trees, fibrillar type trees, intrinsic type, depending on the applied voltage. Weibull studies indicate that a higher applied voltage enhances the rate of tree propagation thereby reducing the life of cable insulation. Measurements of injected current during tree propagation indicates that the rise time and fall time of the signal is of few nano seconds. In the present study, an attempt has been made to identify the partial discharges caused due to inception and propagation of electrical trees adopting UHF technique. It is realized that UHF signal generated during tree growth have signal bandwidth in the range of 0.5-2.0 GHz. The formation of streamer type discharge and Townsend type discharges during tree inception and propagation alters the shape of the tree formed. The UHF signal generated due to partial discharges formed during tree growth were analyzed adopting Ternary plot, which can allow one to classify the shape of tree structure formed.

  18. Improved Electrical Insulation of Rare Earth Permanent Magnetic Materials With High Magnetic Properties

    CHANG Ying; WANG Da-peng; LI Wei; PAN Wei; YU Xiao-jun; QI Min


    Rare earth permanent magnetic materials are typical electrical conductor, and their magnetic properties will decrease because of the eddy current effect, so it is difficult to keep them stable for a long enough time under a high frequency AC field. In the present study, as far as rare earth permanent magnets are concerned, for the first time, rare earth permanent magnets with strong electrical insulation and high magnetic performance have been obtained through experiments, and their properties are as follows:(1) Sm2TM17: Br=0.62 T, jHc=803.7 kA/m, (BH)m= The magnetic properties of Sm2TM17 and NdFeB are obviously higher than those of ferrite permanent magnet, and the electric insulating characteristics of Sm2TM17 and NdFeB applied have in fact been approximately the same as those of ferrite. Therefore, Sm2TM17 and NdFeB will possess the ability to take the place of ferrite under a certain high frequency AC electric field.


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


    In the framework of the European project EuCARD (FP7) aiming at constructing a high magnetic field accelerator magnet of 13 T with Nb3Sn superconducting cables, new electrical insulation are thermally tested. This technology will use “conventional” electrical insulation in combination with pressurized superfluid helium (He II) or saturated helium at atmospheric pressure as coolant. Two composite insulation systems composed of cyanate ester epoxy mix or a tri-functional epoxy (TGPAP-DETDA) with fiberglass tape frame, have been chosen as potential candidates. The knowledge of their thermal properties is necessary for the thermal design and therefore samples have been tested in pressurized He II where heat is applied perpendicularly to the fibers between 1.6 K and 2.0 K. Overall thermal resistance is determined as a function of temperature and the results are compared with other electrical insulation systems used for accelerator magnets.

  20. Numerical Computation of Electric Field and Potential Along Silicone Rubber Insulators Under Contaminated and Dry Band Conditions

    Arshad; Nekahi, A.; McMeekin, S. G.; Farzaneh, M.


    Electrical field distribution along the insulator surface is considered one of the important parameters for the performance evaluation of outdoor insulators. In this paper numerical simulations were carried out to investigate the electric field and potential distribution along silicone rubber insulators under various polluted and dry band conditions. Simulations were performed using commercially available simulation package Comsol Multiphysics based on the finite element method. Various pollution severity levels were simulated by changing the conductivity of pollution layer. Dry bands of 2 cm width were inserted at the high voltage end, ground end, middle part, shed, sheath, and at the junction of shed and sheath to investigate the effect of dry band location and width on electric field and potential distribution. Partial pollution conditions were simulated by applying pollution layer on the top and bottom surface respectively. It was observed from the simulation results that electric field intensity was higher at the metal electrode ends and at the junction of dry bands. Simulation results showed that potential distribution is nonlinear in the case of clean and partially polluted insulator and linear for uniform pollution layer. Dry band formation effect both potential and electric field distribution. Power dissipated along the insulator surface and the resultant heat generation was also studied. The results of this study could be useful in the selection of polymeric insulators for contaminated environments.

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

    Sukhanov, Aleksei A.


    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.

  2. The Application of Novel Polypropylene to the Insulation of Electric Power Cable (3)

    Kurahashi, Kiyoshi; Matsuda, Yoshiji; Miyashita, Yoshitsugu; Demura, Tsuyoshi; Ueda, Asakiyo; Yoshino, Katsumi

    Having higher melting temperature than polyethylene, polypropylene has been expected as insulation material for power cable. But isotactic polypropylene used generally is unsuitable as cable insulation because it shows poor flexibility, low breakdown strength due to growing spherulites, and so on. But stereoregular syndiotactic polypropylene (s-PP) newly developed with metallocene catalyst shows quite different properties from i-PP. The authors had investigated the basic properties of s-PP and the initial properties as a cable which was manufactured using s-PP insulation, in the previous paper. As the results of this, it was revealed that s-PP had superior thermal and electrical properties to cross-linked polyethylene and the s-PP insulation cable showed satisfactory initial properties. However, in order to apply to an actual cable, the properties must be maintainable over 30 years after construction. In this paper, we estimated the long term and remaining properties for s-PP insulation cable. A series of experiments on long term properties gave following results. (1) S-PP cable shows longer life over 30 years. (2) The breakdown strength of s-PP cable after long term experiment equal to 30 years is slightly lower than initial breakdown strength, but it’s sufficient as remaining property. Furthermore, water-tree resistivity of s-PP was investigated and it was revealed that s-PP significantly suppressed the water tree propagation compared with XLPE. These results suggested that s-PP cable would be available as next generation cable.

  3. Properties of Electrical Discharges Developing in Transformer Oil Under Lightning Impulse in the Setup of Insulated Electrodes

    Pawel Rozga


    Looking at the problem of electrical discharge development in mineral oil,it is easy to see that most studies in this area focused on the setups of bare high voltage electrodes having a point-plane electrode arrangement.The setups with insulated electrodes are the margin of these studies but it seems to be important to find the dependences between the paper insulation on high voltage electrode and parameters of the discharges initiated in the vicinity of this electrode.Hence,in this paper the results of researches intended to reveal the role of insulation wrapping on a HV electrode in the mechanism of electrical discharges in transformer oil under lightning impulse of both polarities are presented.This role is determined by analysis of the parameters characterizing the discharges (onset voltage,propagation velocity,time to initiation,rise-time of light impulses) and also by observation of their spatio-temporal development and oscillograms of the light emitted by their channels.The research was performed for two model electrode configurations:an electrode with paper insulation and a bare electrode which had the same outer dimensions as the insulated one.The most essential conclusion from performed experiment is related to times to initation.These times,equal in the case of insulated electrodes and model bare electrode,indicate that the source of"weak points" of the paper-oil insulation system is the oil,not the surface of insulation wrapping or the metal.

  4. Towards thermoconductive, electrically insulating polymeric composites with boron nitride nanotubes as fillers

    Zhi, Chunyi; Bando, Yoshio; Terao, Takeshi; Tang, Chengchun; Golberg, Dimitri [World Premier International Center for Materials Nanoarchitectonics (MANA) National Institute for Materials Science Namiki 1-1, Tsukuba, Ibaraki 305-0044 (Japan); Kuwahara, Hiroaki [Innovation Research Institute, Teijin Ltd. 2-1, Hinode-cho, Iwakuni, Yamaguchi 740-8511 (Japan)


    Utilizing boron nitride nanotubes (BNNTs) as fillers, composites are fabricated with poly(methyl methacrylate), polystyrene, poly(vinyl butyral), or poly(ethylene vinyl alcohol) as the matrix and their thermal, electrical, and mechanical properties are evaluated. More than 20-fold thermal conductivity improvement in BNNT-containing polymers is obtained, and such composites maintain good electrical insulation. The coefficient of thermal expansion (CTE) of the BNNT-loaded polymers is dramatically reduced because of interactions between the polymer chains and the nanotubes. Moreover, the composites possess good mechanical properties, as revealed by Vickers microhardness tests. This detailed study indicates that BNNTs are very promising nanofillers for polymeric composites, allowing the simultaneous achievement of high thermal conductivity, low CTE, and high electrical resistance, as required for novel and efficient heat-releasing materials. (Abstract Copyright [2009], Wiley Periodicals, Inc.)

  5. Electrically Insulative Performances of Ceramic and Clay Films Deposited via Supersonic Spraying

    Lee, Jong-Gun; Kim, Do-Yeon; Joshi, Bhavana N.; Lee, Jong-Hyuk; Lee, Tae-Kyu; Kim, Jang-soo; Yang, Dae-ho; Kim, Woo-Young; Al-Deyab, Salem S.; Yoon, Sam S.


    Supersonic spray coating techniques were applied to deposit ceramic and clay particles as films for use in electrical insulation. TiO2 and Al2O3 ceramics were aerosol-deposited under vacuum while kaolinite, montmorillonite, and bentonite clays were deposited by cold spraying in open air. The electrical resistivity of Al2O3 and TiO2 were ~109 and ~108 Ω cm, respectively. The resistivity of kaolinite and montmorillonite were ~1012 Ω cm. Bentonite showed the lowest electrical resistivity of ~109 Ω cm among the clays because of the high cation exchange capacity of the material. The film surface morphologies and mechanical properties in the form of hardness and scratchability were also investigated.

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

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


    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.

  7. Theory of topological insulator waveguides: polarization control and the enhancement of the magneto-electric effect

    Crosse, J A


    Topological insulators subject to a time-symmetry-breaking perturbation are predicted to display a magneto-electric effect that causes the electric and magnetic induction fields to mix at the material's surface. This effect induces polarization rotations of between ~1-10 mrad per interface in incident plane-polarized light normal to a multilayered structure. Here we show, theoretically and numerically, that, using a waveguide geometry with a topological insulator guide layer and dielectric cladding, it is possible to achieve rotations of between ~100-1000 mrad and generate an elliptical polarization with only a three-layered structure. Both the rotation angle and ellipticity are dependent on the permittivity contrast of the guide and cladding layers and the strength of the time-symmetry-breaking perturbation. This geometry is beneficial, not only as a way to enhance the magneto-electric effect, rendering it easier to observe, but also as a method for controlling the polarization of light in the next generatio...

  8. Realization of Primary Thermometer from Electrical Shot Noise in a Metal-Insulator-Metal Tunnel Junction

    Park, J. H.; Rehman, M.; Choi, J. S.; Song, W.; Chong, Y. [Korea Research Institute of Standards and Science, Daejeon (Korea, Republic of); Khim, Z. G. [Dept. of Physics and Astronomy, Seoul National University, Seoul (Korea, Republic of); Ryu, S. W. [Dept. of Physics, Chonnam National University, Gwangju (Korea, Republic of)


    We measured electrical shot noise in a metal-insulator-metal tunnel junction, which was made by using electron-beam lithography and double-angle evaporation technique. Since the dependence of the shot noise on bias voltage and temperature is theoretically well known, we can determine the temperature of the junction by measuring the noise as the voltage across the junction is changed. A cryogenic low noise amplifier was used to amplify the noise signal in the frequency range of 600-800 MHz, which enabled fast measurement of noise signal and thus temperature. With further study, this method could be useful for primary thermometry in cryogenic temperatures.

  9. Effects of thermocouple electrical insulation on the measurement of surface temperature

    AlWaaly, Ahmed A.Y.; Paul, Manosh C; Dobson, Phillip S.


    Analytical, numerical and experimental analyses have been performed to investigate the effects of thermocouple wire electrical insulation on the temperature measurement of a reference surface. Two diameters of type K thermocouple, 80 μm and 200 μm, with different exposed wire lengths (0 mm, 5 mm, 10 mm, 15 mm and 20 mm) were used to measure various surface temperatures (4 °C, 8 °C, 15 °C, 25 °C and 35 °C). Measurements were made with the thermocouple in direct contact with the surface, with w...

  10. Structure characteristics of electrical treeing in XLPE insulation under high frequencies

    Bao, Minghui; Yin, Xiaogen; He, Junjia


    Electrical tree structure is one of the most important influencing factors for electrical treeing characteristics in polymers. In this paper, we focused on the structure characteristics of electrical treeing in cross-linked polyethylene (XLPE) insulation under high-frequency voltages. The tree structure characteristics include structure distribution characteristics and structure conversion characteristics. The influences of voltage, frequency, and pin-plane spacing on tree structure characteristics were analyzed based on the experimental results. It can be concluded that tree structures regularly change with the local electric field and frequency. The electric field in a very small zone near the needle tip is an important influencing factor for the formation of bush-like trees, and the lowest frequencies for the observed pure-vine-like trees increased with voltage. For double-structure trees, the local electric field at the transition location of the two structures remained almost unchanged with voltage and pin-plane spacing, but obviously increased with frequency. In order to investigate the relations of the growth rate and fractal dimension with tree structure characteristics, a new parameter, the energy threshold Wt, has been introduced and calculated for different tree structures.

  11. Equipment qualification research test of electrical cable with factor splices and insulation rework: Test no. 2, report no. 1

    Minor, E. E.; Furgal, D. T.


    Electric cables with flame retardant chemically crosslinked polyolefin extruded insulation containing factory made center conductor splices and insulation repairs manufactured by the Rockbestos Company were used in a methodology test of the IEEE Standard 383-1974. Cable specimens were radiation aged at a low dose rate and then thermally aged to simulate a 40 year containment exposure. After aging, the specimens were subjected to LOCA radiation and a 33 day steam and chemical spray exposure. The cables were electrically loaded and functioned without failure during and after LOCA steam and chemical spray exposure. Insulation resistance measurements were taken during the exposure sequence. Subsequence to the exposures, hipot and mandrel bend tests were conducted. To determine the most severe cable aging sequence, cable insulation material samples were subjected to varied aging exposure to observe sequence related and dose rate related material degradation. A dose rate effect was observed.

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

    E. Mihailov


    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. Heavily Cr-doped (Bi,Sb2Te3 as a ferromagnetic insulator with electrically tunable conductivity

    Yunbo Ou


    Full Text Available With molecular beam epitaxy we have grown Cry(BixSb1-x2-yTe3 thin films with homogeneous distribution of Cr dopants and Curie temperature up to 77 K. The films with Cr concentration y ≥ 0.39 are found to be topologically trivial, highly insulating ferromagnets, whose conductivity can be tuned over two orders of magnitude by gate voltage. The ferromagnetic insulators with electrically tunable conductivity can be used to realize the quantum anomalous Hall effect at higher temperature in topological insulator heterostructures and to develop field effect devices for spintronic applications.

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

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


    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.

  15. New Experimental Limit on the Electric Dipole Moment of the Electron in a Paramagnetic Insulator

    Kim, Y J; Lamoreaux, S K; Visser, G; Kunkler, B; Matlashov, A V; Kunkler, B


    We report results of an experimental search for the intrinsic Electric Dipole Moment (EDM) of the electron using a solid-state technique. The experiment employs a paramagnetic, insulating gadolinium gallium garnet (GGG) that has a large magnetic response at low temperatures. The presence of the eEDM would lead to a small but non-zero magnetization as the GGG sample is subject to a strong electric field. We search for the resulting Stark-induced magnetization with a sensitive magnetometer. Recent progress on the suppression of several sources of background allows the experiment to run free of spurious signals at the level of the statistical uncertainties. We report our first limit on the eEDM of $(-5.57 \\pm 7.98 \\pm 0.12)\\times10^{-25}$e$\\cdot$cm with 5 days of data averaging.

  16. A real time affinity biosensor on an insulated polymer using electric impedance spectroscopy in dielectric microchips.

    Kechadi, Mohammed; Sotta, Bruno; Chaal, Lila; Tribollet, Bernard; Gamby, Jean


    This paper presents development of real time monitoring of binding events on flexible plastic in microchips. Two planar carbon microelectrodes are integrated into an insulated polyethylene terephthalate microchip without direct electrical contact with the solution in the microchannel. It has been possible to probe the electric impedance changes through the interface constituted by the microelectrode/PET microchannel/solution when a biomolecular interaction takes place on the polymer surface. This new transduction for biosensing was demonstrated for the molecular recognition of BSA immobilized on the polymer microchannel surface using the corresponding rabbit anti-BSA antibodies as an analyte in the flow microchannel at the nanomolar range concentration. The equilibrium association constant was determined for the affinity reaction between both ligands and was obtained equal to 5 × 10(7) M(-1). The promising results obtained with this new device make it a competitive biosensor.

  17. Electric-field control of spin-orbit torque in a magnetically doped topological insulator

    Fan, Yabin; Kou, Xufeng; Upadhyaya, Pramey; Shao, Qiming; Pan, Lei; Lang, Murong; Che, Xiaoyu; Tang, Jianshi; Montazeri, Mohammad; Murata, Koichi; Chang, Li-Te; Akyol, Mustafa; Yu, Guoqiang; Nie, Tianxiao; Wong, Kin L.; Liu, Jun; Wang, Yong; Tserkovnyak, Yaroslav; Wang, Kang L.


    Electric-field manipulation of magnetic order has proved of both fundamental and technological importance in spintronic devices. So far, electric-field control of ferromagnetism, magnetization and magnetic anisotropy has been explored in various magnetic materials, but the efficient electric-field control of spin-orbit torque (SOT) still remains elusive. Here, we report the effective electric-field control of a giant SOT in a Cr-doped topological insulator (TI) thin film using a top-gate field-effect transistor structure. The SOT strength can be modulated by a factor of four within the accessible gate voltage range, and it shows strong correlation with the spin-polarized surface current in the film. Furthermore, we demonstrate the magnetization switching by scanning gate voltage with constant current and in-plane magnetic field applied in the film. The effective electric-field control of SOT and the giant spin-torque efficiency in Cr-doped TI may lead to the development of energy-efficient gate-controlled spin-torque devices compatible with modern field-effect semiconductor technologies.

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

    Engster F.


    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.

  19. The Application of Novel Polypropylene to the Insulation of Electric Power Cable (2)

    Miyashita, Yoshitsugu; Demura, Tsuyoshi; Ueda, Asakiyo; Someya, Akira; Kawahigashi, Masaki; Murakami, Tsuyoshi; Matsuda, Yoshiji; Kurahashi, Kiyoshi; Yoshino, Katsumi

    The authors had investigated the basic properties of newly developed stereoregular syndiotactic polypropylene (s-PP) which had been synthesized with homogeneous metallocene catalyst, in the previous paper. As the result of this, it was revealed that s-PP had superior thermal and electrical properties to cross-linked polyethylene (XLPE) which was adopted as conventional insulating material for high voltage power cable. In this paper, we estimated the possibility to apply s-PP to the actual power cable from the viewpoint of long-term thermal durability and processability. Consequently, it was found that the thermal stability of s-PP could be significantly improved by adding both hindered phenol and sulfur antioxidants, and wide molecular weight distribution of s-PP contributed to good processability during extrusion. On the basis of these results, 600V and 22kV class cables with insulation of s-PP were manufactured. Successfully manufactured cables proposed that s-PP could be available to electric power cable. Lightning Impulse and AC breakdown strength of both cables at the temperature range of RT to 120°C will be discussed.

  20. All-electrical generation of spin-polarized currents in quantum spin Hall insulators

    Tao, L. L.; Cheung, K. T.; Zhang, L.; Wang, J.


    The control and generation of spin-polarized current (SPC) without magnetic materials and an external magnetic field is a big challenge in spintronics and normally requires a spin-flip mechanism. In this Rapid Communication, we show the theoretical discovery of all-electrical generation of SPC without relying on spin-flip spin-orbit coupling (SOC). We find that the SPC can be produced as long as an energy-dependent phase difference between the spin up and down electrons can be established. We verify this through quantum transport calculations on a gated stanene zigzag nanoribbon, which is a quantum spin Hall (QSH) insulator. Our calculations indicate that the transient current as well as ac conductance are significantly spin polarized, which results from the genetic phase difference between spin up and down electrons after traversing the system. Our results are robust against edge imperfections and generally valid for other QSH insulators, such as silicene and germanene, etc. These findings establish a different route for generating SPCs by purely electrical means and open the door for interesting applications of semiconductor spintronics.

  1. Inertial confinement fusion with direct electric generation by magnetic flux comparession

    Lasche, G.P.


    A high-power-density laser-fusion-reactor concept in investigated in which directed kinetic enery imparted to a large mass of liquid lithium--in which the fusion target is centrally located--is maximized. In turn, this kinetic energy is converted directly to electricity with, potentially, very high efficiency by work done against a pulsed magnetic field applied exterior to the lithium. Because the concept maximizes the blanket thickness per unit volume of lithium, neutron-induced radioactivities in the reaction chamber wall can be many orders of magnitude less than is typical of D-T fusion reactor concepts.

  2. Structural and electrical properties of SrTiO3 thin films as insulator of metal-ferroelectric-insulator-semiconductor (MFIS) structures

    Ma Jian-Hua; Meng Xiang-Jian; Lin Tie; Liu Shi-Jian; Zhang Xiao-Dong; Sun Jing-Lan; Chu Jun-Hao


    SrTiO3 (STO) thin films were deposited on p-Si(100) substrates at various substrate temperatures from 300℃to 700℃ by radio frequency (RF) magnetron sputtering technique. Their structure and electrical properties were investigated. It was found that the transition from amorphous phase to polycrystalline phase occurred at the substrate temperatures 300-400℃. Their crystallinity became better when the substrate temperatures further increased. The dielectric and leakage current measurements were carried out by using the Si/STO/Pt metal-insulator-semiconductor (MIS) structures at roon temperature. It was found that the fixed charge density decreased and both the interface trap density and the dielectric constant increased when the substrate temperatures were increased. The leakage current mechanisms for STO MIS structures with STO films prepared at 700℃ followed the space charge limited current (SCLC)under the low applied electric field and the Poole-Frenkel emission under the high one. In addition, the resistivity for films prepared at 700℃ was higher than 1011Ω.cm under the voltage lower than 10V (corresponding to the electric field of 1.54× It suggested that the STO films prepared at 700℃ were suitable for acting as the insulator of metal-ferroelectric-insulator-semiconductor (MFIS) structures.

  3. A Novel Electrical Insulating Material for 275 kV High-Voltage HTS Cable with Low Dielectric Loss

    Hayakawa, N.; Nishimachi, S.; Maruyama, O.; Ohkuma, T.; Liu, J.; Yagi, M.


    In the case of high temperature superconducting (HTS) power transmission cables at high voltage operation, the electrical insulation technique in consideration of the dielectric loss reduction becomes crucial. In this paper, we focused on a Tyvek/polyethylene (PE) sheet, instead of the conventional polypropylene laminated paper (PPLP). We obtained the dielectric characteristics (epsilonr, tanδ) and partial discharge inception strength (PDIE) of PPLP, Tyvek and Tyvek/PE. We pointed out that the dielectric loss of 275 kV HTS cable with Tyvek/PE insulation will be reduced to 21 % of that with PPLP, and the total electrical loss including the AC loss will be reduced to 41 %.

  4. An effect of nuclear electric quadrupole moments in thermonuclear fusion plasmas

    De, B. R.; Srnka, L. J.


    Consideration of the nuclear electric quadrupole terms in the expression for the fusion Coulomb barrier suggests that this electrostatic barrier may be substantially modified from that calculated under the usual plasma assumption that the nuclei are electric monopoles. This effect is a result of the nonspherical potential shape and the spatial quantization of the nuclear spins of the fully stripped ions in the presence of a magnetic field. For monopole-quadrupole fuel cycles like p-B-11, the fusion cross-section may be substantially increased at low energies if the protons are injected at a small angle relative to the confining magnetic field.

  5. Development of dielectrophoresis separator with an insulating porous membrane using DC-Offset AC Electric Fields.

    Hakoda, Masaru


    Our previous studies revealed that the dielectrophoresis method is effective for separating cells having different dielectric properties. The purpose of this study was to evaluate the separation characteristics of two kinds of cells by direct current (DC) voltage offset/alternating current (AC) voltage using an insulating porous membrane dielectrophoretic separator. The separation device gives dielectrophoretic (DEP) force and electrophoretic (EP) force to dispersed particles by applying the DC-offset AC voltage. This device separates cells of different DEP properties by adopting a structure in which only the parallel plate electrodes and the insulating porous membrane are disposed in the flow path through which the cell-suspension flows. The difference in the retention ratios of electrically homogeneous 4.5 μm or 20.0 μm diameter standard particles was a maximum of 82 points. Furthermore, the influences of the AC voltage or offset voltage on the retention ratios of mouse hybridoma 3-2H3 cells and horse red blood cells (HRBC) were investigated. The difference in the retention ratio of the two kinds of cells was a maximum of 56 points. The separation efficiency of this device is expected to be improved by changing the device shape, number of pores, and pore placement. © 2016 American Institute of Chemical Engineers Biotechnol. Prog., 32:1292-1300, 2016.

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

    Markey, L.; Stevens, G. C.


    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.

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

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


    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.

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

    Julionas KALADE


    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.

  9. Comparison of the formation of electric charge in XLPE insulation with solid and liquid antioxidants by TSDC technique

    Idalberto Tamayo Ávila


    Full Text Available (Received: 2014/10/29 - Accepted: 2014/12/17In this paper the presence of electric charge in two insulation of cross-linked polyethylene (XLPE in medium voltage cables was compared using the technique of Thermally Stimulated Depolarization Currents (TSDC. Antioxidant in solid form was added to one of the insulation, and in liquid form to the other. By analyzing the TSDC measures we verified that the use of liquid antioxidant is better because the solid antioxidant creates defects that act as centers for trapping the space charge. In these centers the ionized charge, by the combined effect of temperature and electric field, is accumulated in the insulation, in addition to the charge injected from the semiconductor electrodes by the effect of high fields.

  10. Confined states and spin polarization on a topological insulator thin film modulated by an electric potential

    Liu Yi-Man; Shao Huai-Hua; Zhou Xiao-Ying; Zhou Guang-Hui


    We study the electronic structure and spin polarization of the surface states of a three-dimensional topological insulator thin film modulated by an electrical potential well.By routinely solving the low-energy surface Dirac equation for the system,we demonstrate that confined surface states exist,in which the electron density is almost localized inside the well and exponentially decayed outside in real space,and that their subband dispersions are quasilinear with respect to the propagating wavevector.Interestingly,the top and bottom surface confined states with the same density distribution have opposite spin polarizations due to the hybridization between the two surfaces.Along with the mathematical analysis,we provide an intuitive,topological understanding of the effect.

  11. Heat transfer through the electrical insulation of Nb3Sn cables

    Granieri, P; van Weelderen, R


    For the LHC upgrade projects, CERN will rely on the Nb3Sn technology to build high field dipole and quadrupole superconducting magnets. In the frame of this R&D program, cooling studies are carried out to determine the heat extraction from this new type of accelerator magnets and the relevant quench limits. In this paper we present and discuss experimental results of heat transfer through the electrical insulation of Nb3Sn cables. A cable-stack was prepared using fiberglass sleeves and CTD-101K impregnation resin. Two different measurement methods were compared, consisting of instrumenting the sample before or after the vacuum impregnation. The tests were performed both in 1.9 K superfluid and 4.2 K liquid helium baths, using different heating configurations. We also present results of the numerical model developed to reproduce the experimental results.

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

    Xiao, Xianbo; Ai, Guoping [School of Computer Science, Jiangxi University of Traditional Chinese Medicine, Nanchang 330004 (China); Liu, Ying; Yang, Shengyuan A., E-mail: [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: [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)


    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.

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

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


    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 microM fluorescein and 50 microM 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.

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

    Mogensen, K B; Boggild, P; Kutter, J P [Department of Micro- and Nanotechnology, Technical University of Denmark, 2800 Kongens Lyngby (Denmark); Gangloff, L; Teo, K B K; Milne, W I [Electrical Engineering Division, Department of Engineering, University of Cambridge, 9 J J Thomson Avenue, Cambridge CB3 0FA (United Kingdom)], E-mail:


    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.

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

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


    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.

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

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


    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.

  17. Electrical Transport and Thermal Expansion in van der Waals Materials: Graphene and Topological Insulator

    Jing, Lei

    Novel two-dimensional materials with weak interlayer Van der Waals interaction are fantastic platforms to study novel physical phenomena. This thesis describes our investigation on two different Van der Waals materials: graphene and bismuth selenide with calcium doping (CaxBi 2-xSe3, x as the doping level) in the topological insulator family. Firstly, we characterize the electrical transport behaviors of high-quality substrate-supported bilayer graphene devices with suspended metal gates. The device exhibits a transport gap induced by external electric field with an on/off ratio of 20,000, which could be explained by variable range hoping between localized states or disordered charge puddles. At large magnetic field, the device presents quantum Hall plateau at fractional values of conductance quantum, which arises from the equilibration of edge states between differentially doped regions. Secondly, we present our study on the electronic transport of CaxBi 2-xSe3 thin films, which are three-dimensional topological insulators and coupled with superconducting leads. In these novel Josephson transistors, we observe different characteristic features by energy dispersion spectrum (EDS) and Raman spectroscopy, and the weak suppression in the critical current Ic. Thirdly, we explore the thermal expansion of suspended graphene. By in-situ scanning electron microscope (SEM), we measure the thickness-dependence of graphene's negative thermal expansion coefficient (TEC). We propose that there is a competitive relation between the intrinsic TEC and the friction from the substrate and the graphene. Lastly, in collaboration with Dr. Nikolai Kalugin from New Mexico Tech., we explore the graphene's application as a quantum Hall effect infrared photodetector. This graphene-based detector can be operated at higher temperature (liquid nitrogen) and wider frequency than the previous implementations of quantum Hall detector.

  18. Fusion

    Mahaffey, James A


    As energy problems of the world grow, work toward fusion power continues at a greater pace than ever before. The topic of fusion is one that is often met with the most recognition and interest in the nuclear power arena. Written in clear and jargon-free prose, Fusion explores the big bang of creation to the blackout death of worn-out stars. A brief history of fusion research, beginning with the first tentative theories in the early 20th century, is also discussed, as well as the race for fusion power. This brand-new, full-color resource examines the various programs currently being funded or p

  19. Application of polymeric solid materials for electrical insulation system in superconducting apparatuses; Chodendo kiki no denki zetsuen kosei ni okeru kobunshi kotai zetsuen no tekiyo

    Nagao, M. [Toyohashi Univ. of Tech., Aichi (Japan); Minoda, A. [Matsue National College of Tech., Shimane (Japan); Kosaki, M. [Gifu National College of Tech., Gifu (Japan)


    We send the electric insulation to one of the technological problem to be solved in order to realize high reliability of the superconductive electric power equipment. This paper must also sufficiently consider not only dielectric characteristic and insulation characteristic but also material mechanical property in which they are excellent at very low temperature in the selection of insulating material. The representative insulating material of XLPE, LDPE mainly used in the region over room temperature the crack may arise by causing mechanical stress by cooling contracture of giant molecule, and the problem occurs as cryogenic insulating material in mechanical property. We propose the ethylene propylene rubber as cryogenic insulating material, and we carry out research and development of superconducting cable of the solid insulation system. We examined dielectric breakdown property and mechanical property of EPR at very low temperature this time. (NEDO)

  20. Compaction of insulated 145 kV electric power substations; Compactacao de subestacoes abrigadas de 145 kV

    Sueta, Helio Eiji; Castro Neto, Gervasio L. [Sao Paulo Univ., SP (Brazil). Inst. de Eletrotecnica e Energia; Porto, Walmar Freitas [Eletricidade de Sao Paulo, Sao Paulo, SP (Brazil)


    Considering the increasing reduction in the areas of insulated 145 kV electric power substations, the most commonly adopted solution has been the vertical organization. This work proposes the reduction of the total area through the reduction of the area designed to high voltage installations, using smaller phase-to-phase distances than the traditionally used ones 5 refs., 4 figs.

  1. Metal-insulator transition in epitaxial NdNiO3 thin film: A structural, electrical and optical study

    Shao, Tao; Qi, Zeming; Wang, Yuyin; Li, Yuanyuan; Yang, Mei; Hu, Chuansheng


    NdNiO3 thin film has been prepared by pulsed laser deposition on LaAlO3 (001) single crystalline substrate. Temperature-dependent resistivity measurement shows a sharp metal-insulator transition in such thin film. The phase transition temperature can be tuned from 90 K to 121 K by changing the thickness of thin film. The structure evolution during phase transition is studied by Raman spectroscopy. Optical conductivity reveals that the variation carrier density in the process of phase transition. The results of structural, electrical and optical studies provide useful insights to understand the mechanism of metal-insulator transition of NdNiO3 thin film.

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

    Xun, Wei; Hao, Xiang; Pan, Tao; Zhong, Jia-Lin; Ma, Chun-Lan; Hou, Fang; Wu, Yin-Zhong


    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.

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

    Wei Xun


    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.

  4. Four allotropes of semiconducting layered arsenic that switch into a topological insulator via an electric field: Computational study

    Mardanya, Sougata; Thakur, Vinay Kumar; Bhowmick, Somnath; Agarwal, Amit


    We propose four different thermodynamically stable structural phases of arsenic monolayers based on ab initio density functional theory calculations, all of which undergo a topological phase transition on application of a perpendicular electric field. All four arsenic monolayer allotropes have a wide band gap, varying from 1.21 to 3.0 eV (based on GW calculations), and in general they undergo a metal-insulator quantum phase transition on application of uniaxial in-layer strain. Additionally, an increasing transverse electric field induces band inversion at the Γ point in all four monolayer allotropes, leading to a nontrivial topological phase (insulating for three allotropes and metallic for one allotrope), characterized by the switching of the Z2 index from 0 (before band inversion) to 1 (after band inversion). The topological phase tuned by the transverse electric field should support spin-separated gapless edge states which should manifest in the quantum spin Hall effect.

  5. Materials for Fusion Applications

    Jiří Matějíček


    Full Text Available An overview of materials foreseen for use or already used in fusion devices is given. The operating conditions, material requirements and characteristics of candidate materials in several specific application segments are briefly reviewed. These include: construction materials, electrical insulation, permeation barriers and plasma facing components. Special attention will be paid to the latter and to the issues of plasma-material interaction, materials joining and fuctionally graded interlayers.

  6. Determination of the Power Transformer Efficiency Monitoring the Electrical Insulation Parameters

    Adrian Munteanu


    Full Text Available The paper presents the monitoring methods for the insulating state of power transformers. For a transformer with oil-paper insulation system the ageing curves was obtained using the criterion of insulating resistance, and the correction coefficients for directly obtained the real insulation resistance. All these measurements are realized on the same transformer with S = 250 MVA power and 400/110/20 kV voltages. Using graphical method, the lifetime of insulation, respectively, of transformer is possible to be quickly obtained.

  7. Effect of Electric Field and Polarity on Light Emission in Metal-Insulator-Semiconductor Structure Thin-Film Electroluminescent Devices

    Ohwaki, Jun-ichi; Kozawaguchi, Haruki; Tsujiyama, Bunjiro


    Changes in the emission intensities and spectra with applied electric fields in Metal-Insulator-Semiconductor (MIS) structure thin-film electroluminescent (TFEL) devices have been investigated using devices with stacked emitting layer structures, such as ITO/ZnS: Mn/ZnS: Tb/Sm2O3/Al. In MIS-TFEL devices, the emission distribution in the direction of the ZnS film thickness is nonhomogeneous. In particular, the emission intensity in the region near the ZnS-insulator interface increases with increasing applied voltage more than in the other region in the ZnS layer, when electrons exciting emission centers are accelerated from the insulator side. On the other hand, the emission is homogeneous at the opposite polarity. It is found that the emission color for stacked emitting layer MIS-TFEL devices can be modulated by changing the applied voltage.

  8. Fusion Reactor Materials

    Decreton, M


    SCK-CEN's research and development programme on fusion reactor materials includes: (1) the study of the mechanical behaviour of structural materials under neutron irradiation (including steels, inconel, molybdenum, chromium); (2) the determination and modelling of the characteristics of irradiated first wall materials such as beryllium; (3) the detection of abrupt electrical degradation of insulating ceramics under high temperature and neutron irradiation; (4) the study of the dismantling and waste disposal strategy for fusion reactors.; (5) a feasibility study for the testing of blanket modules under neutron radiation. Main achievements in these topical areas in the year 1999 are summarised.

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

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


    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.

  10. Cobalt iron-oxide nanoparticle modified poly(methyl methacrylate) nanodielectrics. Dielectric and electrical insulation properties

    Tuncer, Enis; Rondinone, Adam J.; Woodward, Jonathan; Sauers, Isidor; James, D. Randy; Ellis, Alvin R.


    In this paper, we report the dielectric properties of composite systems (nanodielectrics) made of small amounts of mono dispersed magnetic nanoparticles embedded in a polymer matrix. It is observed from the transmission electron microscope images that the matrix polymeric material is confined in approximately 100 nm size cages between particle clusters. The particle clusters are composed of separated spherical particles which comprise unconnected networks in the matrix. The dielectric relaxation and breakdown characteristics of the matrix polymeric material are altered with the addition of nanometer size cobalt iron-oxide particles. The dielectric breakdown measurements performed at 77 K showed that these nanodielectrics are potentially useful as an electrical insulation material for cryogenic high voltage applications. Finally, structural and dielectric properties of nanocomposite dielectrics are discussed to present plausible reasons for the observed low effective dielectric permittivity values in the present and similar nanodielectric systems. It is concluded that polymeric nanoparticle composites would have low dielectric permittivity regardless of the permittivity of nanoparticles are when the particles are coordinated with a low dielectric permittivity surfactant.

  11. Electrically controlled spin polarization and selection in a topological insulator sandwiched between ferromagnetic electrodes

    Guo, Junji; Liao, Wenhu, E-mail:; Zhao, Heping [College of Physics, Mechanical and Electrical Engineering, Jishou University, Jishou 416000 (China); Zhou, Guanghui [Department of Physics and Key Laboratory for Low-Dimensional Quantum Structures and Manipulation (Ministry of Education), Hunan Normal University, Changsha 410081 (China)


    We theoretically investigate the electrically controllable spin polarization and selective efficiency of the edge state Dirac electron in a two-dimensional topological insulator (TI) sandwiched between ferromagnetic (FM) electrodes by using the method of Keldysh nonequilibrium Green's function. A nearly full spin polarization of the topological edge state with giant inversion of ∼80% is observed, which is much higher than the value previously reported. Moreover, the selective efficiency for spin-up electrons under the modulation of the parallel configuration of FM electrodes has been demonstrated to be larger than 95% for the first time, while that for spin-down electrons in the antiparallel case is higher than 90% in a wide energy range, owing to the inter-edge spin tunneling induced backscattering and spin dephasing effect. The obtained results may provide a deeper understanding of the TI edge states and a valuable guidance to design spin switch and filter with high on-off speed and selective efficiency based on TIs.

  12. Electric-field control of spin-orbit torque in magnetically doped topological insulators

    Fan, Yabin; Shao, Qiming; Kou, Xufeng; Upadhyaya, Pramey; Wang, Kang

    Recent advances of spin-orbit torques (SOTs) generated by topological insulators (TIs) have drawn increasing interest to the spin-momentum locking feature of TIs' surface states, which can potentially provide a very efficient means to generate SOTs for spintronic applications. In this presentation, we will show the magnetization switching through current-induced giant SOT in both TI/Cr-doped TI bilayer and uniformly Cr-doped TI films In particular, we show that the current-induced SOT has significant contribution from the spin-momentum locked surface states of TIs. We find that the spin torque efficiency is in general three orders of magnitude larger than those reported in heavy metal/ferromagnetic heterostructures. In the second part, we will present the electric-field control of the giant SOT in magnetically doped TIs, which suggests promising gate-controlled spin-torque device applications. The giant SOT and efficient current-induced magnetization switching exhibited by the magnetic TIs may lead to innovative spintronic applications such as ultralow power dissipation memory and logic devices. We acknowledge the supports from DARPA, FAME, SHINES and ARO programs.

  13. Effect of Copper/Graphite Addition on Electrical Conductivity and Thermal Insulation of Unsaturated Polyester/Jute Composites

    Biswas, Bhabatosh; Chabri, Sumit; Mitra, Bhairab Chandra; Das, Kunal; Bandyopadhyay, Nil Ratan; Sinha, Arijit


    Jute fibre along with Cu particle reinforced unsaturated polyester composites having different filler loading viz. 2, 5, 10 and 15 wt% were fabricated by compression molding technique. In present investigation, it was observed that with fillers (Jute and Cu) incorporation, the electrical conductivity was monotonically increased up to 10 wt% of filler content followed by saturation at 15 wt% of filler content. It was further observed that along with fillers (Jute and Cu) incorporation, the thermal insulation was decreased monotonically up to 10 wt% of filler content and achieved a saturation at 15 wt% of filler content. A similar trend was observed with the variation of electrical conductivity and thermal insulation after incorporation of graphite within copper reinforced UP/Jute composites. Structural investigation through SEM, XRD and FTIR confirm the dispersion of fillers. An improvement of crystallinity of the matrix with fillers addition was observed from XRD analyses. The interfacial bonding between fillers and matrix was studied from FTIR pattern.

  14. Cr doped topological insulator Bi2Se3 under external electric field: A first-principle study

    Lian, Ruqian; Zhang, Jian-Min; Yang, Yanmin; Xu, Guigui; Zhong, Kehua; Huang, Zhigao


    In this paper, we investigated the magnetic topological insulator (MTI) Cr-doped Bi2Se3 film using first principles calculations based on the density functional theory (DFT). The band structure of Cr doped 3QL-Bi2Se3 film was calculated comparing with pure Bi2Se3 film. Our results demonstrate that the doping of Cr atom changes the degenerate surface state of pure Bi2Se3, inducing the ferromagnetism. Under the external electric field, the band gap of pure Bi2Se3 films is determined by the charge transfer and the effect of spin-orbital coupling (SOC). For the MTI, the electric field will redistribute the electrons and enhance the magnetism. Our results will further promote the development of the electronic and spintronic applications of topological insulator.

  15. Fusion

    Herman, Robin


    The book abounds with fascinating anecdotes about fusion's rocky path: the spurious claim by Argentine dictator Juan Peron in 1951 that his country had built a working fusion reactor, the rush by the United States to drop secrecy and publicize its fusion work as a propaganda offensive after the Russian success with Sputnik; the fortune Penthouse magazine publisher Bob Guccione sank into an unconventional fusion device, the skepticism that met an assertion by two University of Utah chemists in 1989 that they had created "cold fusion" in a bottle. Aimed at a general audience, the book describes the scientific basis of controlled fusion--the fusing of atomic nuclei, under conditions hotter than the sun, to release energy. Using personal recollections of scientists involved, it traces the history of this little-known international race that began during the Cold War in secret laboratories in the United States, Great Britain and the Soviet Union, and evolved into an astonishingly open collaboration between East and West.

  16. Surface Electrical Field Distribution Simulation and Insulation Characteristics Test of Polluted Insulators%污秽绝缘子表面电场分布仿真及绝缘特性试验

    霍锋; 陈勇; 蔡炜


    In this paper, the electrical fields along the insulator surface under different scenarios, such as asymmetric pollution on top/bottom surface, and uneven circumferential distribution of surface pollution, have been calculated with finite element method for field simulation. Tests on artificial pollution insulators are conducted to study the 50% withstand voltage U50 of artificial pollution suspension insulators under different NSDD(non-soluble deposit density) and asymmetric pollution on the top/bottom surface , and study the change of leakage current with air humidity under different voltage and different ESDD(equivalent salt deposit density). The result shows that asymmetric top/bottom surface pollution has a greater impact on the insulator electrical field distribution, and the leakage current will jump under low air humidity, if had large ESDD, which has practical meanings to the anti-pollution design of the transmission line under different pollution levels across the country.

  17. Radiochemical problems of fusion reactors. 1. Facilities

    Crespi, M.B.A.


    A list of fusion reactor candidate materials is given, for use in connection with blanket structure, breeding, moderation, neutron multiplication, cooling, magnetic field generation, electrical insulation and radiation shielding. The phenomena being studied for each group of materials are indicated. Suitable irradiation test facilities are discussed under the headings (1) accelerator-based neutron sources, (2) fission reactors, and (3) ion accelerators.

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

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


    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. Electric-field tuning of the surface band structure of topological insulator Sb2Te3 thin films.

    Zhang, Tong; Ha, Jeonghoon; Levy, Niv; Kuk, Young; Stroscio, Joseph


    We measured the response of the surface state spectrum of epitaxial Sb(2)Te(3) thin films to applied gate electric fields by low temperature scanning tunneling microscopy. The gate dependent shift of the Fermi level and the screening effect from bulk carriers vary as a function of film thickness. We observed a gap opening at the Dirac point for films thinner than four quintuple layers, due to the coupling of the top and bottom surfaces. Moreover, the top surface state band gap of the three quintuple layer films was found to be tunable by a back gate, indicating the possibility of observing a topological phase transition in this system. Our results are well explained by an effective model of 3D topological insulator thin films with structure inversion asymmetry, indicating that three quintuple layer Sb(2)Te(3) films are topologically nontrivial and belong to the quantum spin Hall insulator class.

  20. Pressure evolution of electrical transport in the 3D topological insulator (Bi,Sb)2(Te,Se)3

    Jeffries, Jason; Butch, N. P.; Vohra, Y. K.; Weir, S. T.


    The group V-VI compounds--like Bi2Se3, Sb2Te3, or Bi2Te3--have been widely studied in recent years for their bulk topological properties. The high-Z members of this series form with the same crystal structure, and are therefore amenable to isostructural substitution studies. It is possible to tune the Bi-Sb and Te-Se ratios such that the material exhibits insulating behavior, thus providing an excellent platform for understanding how a topological insulator evolves with applied pressure. We report our observations of the pressure-dependent electrical transport and compare that behavior with other binary V-VI compounds under pressure. Lawrence Livermore National Laboratory is operated by Lawrence Livermore National Security, LLC, for the U.S. Department of Energy, National Nuclear Security Administration under Contract DE-AC52-07NA27344.

  1. Ex vivo Time Evolution of Thrombus Growth through Optical and Electrical Impedance data fusion

    Affanni, A.; Specogna, R.; Trevisan, F.


    We designed a novel sensor specifically aimed at ex vivo measurements of white thrombus volume growth; a white thrombus is induced within an artificial micro-channel where hemostasis takes place starting from whole blood under flow conditions. The advantage of the proposed methodology is to identify the time evolution of the thrombus volume by means of an original data fusion methodology based on 2D optical and electrical impedance data simultaneously processed. On the contrary, the present state of the art optical imaging methodologies allow the thrombus volume estimation only at the end of the hemostatic process.

  2. Numerical Modeling of the Electric Field and the Potential Distributions in Heterogeneous Cavities inside XLPE Power Cable Insulation



    Full Text Available The XLPE power cable is easily affected by heterogeneous cavities: air void cavity, vented and bow-tie water trees. In this paper, we present a numerical modeling of this cable. A number of simulations are realized in order to analyze the influence of heterogeneous cavities and the influence of their positions and sizes on the electric field distribution, the potential distribution and the degradation of the XLPE insulation. The models are implemented with the finite element method based on the software package COMSOL Multiphysics.

  3. Preparation and Electrical Properties of Insulation Paper Composed of SiO2 Hollow Spheres

    Chao Tang


    Full Text Available SiO2 hollow spheres and low relative permittivity insulation paper handsheets composed of these SiO2 hollow spheres with different weight percentages were successfully prepared. Low-content SiO2 hollow spheres were uniformly dispersed in the insulation paper handsheets. The relative permittivity of the immersed oil Kraft-SiO2 hollow sphere handsheets (K-SiO2 initially decreased and then increased with increased amount of SiO2 hollow spheres. K-5% SiO2 possessed the lowest relative permittivity of approximately 1.68 at 50 Hz. The breakdown voltage of the paper-oil-paper composite insulation system increased from 26.4 kV to 30.5 kV with decreased relative permittivity of the paper from 2.55 to 1.68. The relationship between the relative permittivity and electric field strength of typical samples were also calculated.

  4. An indirect method to measure the electric charge deposited on insulators during PIXE analysis

    Dinator, M.I.; Cancino, S.A.; Miranda, P.A. [Departamento de Fisica, Facultad de Ciencias, Universidad de Chile, Las Palmeras 3425, Nunoa, Santiago (Chile); Morales, J.R. [Departamento de Fisica, Facultad de Ciencias, Universidad de Chile, Las Palmeras 3425, Nunoa, Santiago (Chile)], E-mail:; Seelenfreund, A. [Universidad Academia de Humanismo Cristiano, Condell 343, Providencia, Santiago (Chile)


    Total charge deposited by a proton beam in an insulator during PIXE analysis has been indirectly determined using a Mylar film coated with cobalt. Elemental concentrations in the samples, pieces of volcanic glass, were obtained and compared to concentrations determined by ICP OES on the same samples. The strong agreement between these results shows the accuracy of the charge determined by this method.

  5. Determination of threshold and maximum operating electric stresses for selected high voltage insulation. Task 3: Investigation of high voltage capacitor insulation

    Sosnowski, M.; Eager, G. S., Jr.


    The threshold voltage of capacitor insulation was investigated. The experimental work was performed on samples prepared from commercial polypropylene insulated, liquid-filled capacitors. The samples were vacuum-impregnated with the original capacitor insulating liquid obtained from the manufacturer. A limited number of full-size capacitor elements also were tested. Impulse voltage breakdown tests with dc voltage prestressing were performed at room temperature and 75 C. From the results of these tests, the threshold voltage of the samples of the capacitor insulation was determined at both temperatures and that of the whole capacitor elements at room temperature. The threshold voltage of the capacitor insulation was found to be approximately equal to the impulse breakdown voltage. No difference was found between the threshold voltage at room temperature and at 75 C. The threshold voltage of the whole capacitor elements at room temperature was found to be equal to approximately 80% of the threshold voltage of the capacitor insulation samples.

  6. High thermally conductive and electrically insulating 2D boron nitride nanosheet for efficient heat dissipation of high-power transistors

    Lin, Ziyuan; Liu, Chunru; Chai, Yang


    High-power transistors suffer greatly from inefficient heat dissipation of the hotspots, which elevate the local temperature and significantly degrade the performance and reliability of the high-power devices. Although various thermal management methods at package-level have been demonstrated, the heat dissipation from non-uniform hotspots at micro/nanoscale still persist in the high power transistors. Here, we develop a method for local thermal management using thermally conductive and electrical insulating few-layer hexagonal boron nitride (h-BN) as heat spreaders and thick counterpart as heat sinks. The electrically insulating characteristic of h-BN nanosheet allows it to be intimately contacted with the hotspot region that is located at the gate electrode edge near the drain side of a high-electron-mobility transistor (HEMT). The high thermal conductivity of h-BN nanosheet, which is quantitatively measured by Raman thermography, reduces the temperature of the hotspot by introducing an additional heat transporting pathway. Our DC and radio-frequency characterizations of the HEMT show the improvement of saturation current, cut-off frequency and maximum oscillation frequency. The finite element simulations show a temperature decrease of ∼32 °C at the hotspot with the use of h-BN nanosheet. This method can be further extended for the micro/nanoscale thermal management of other high-power devices.

  7. Electrical characterization of a-C:H as a dielectric material in metal/insulator/metal structures

    Zuniga-I., C.; Kosarev, A.; Torres-J., A.; Rosales-Q., P.; Calleja-A., W.; Hidalga-W., F.J. de la; Malik, O. [Electronic' s Department, National Institute for Astrophysics, Optics, and Electronics, INAOE, Puebla (Mexico)


    The fabrication and electrical characterization of Metal-Insulator-Metal (MIM) structures, using a-C:H films as the insulating material, are presented in this work. These PECVD carbon films show a very low dielectric constant and a very high resistivity. The current conduction mechanisms were analyzed before and after the post deposition annealing in pure argon ambient at 400 C. For as-deposited films, the experimental J -U curves showed that under low biasing regime (vertical stroke U vertical stroke <8 V) the space charge limited current conduction is the main transport mechanism, whereas under higher biasing regime (vertical stroke U vertical stroke >8 V) the current transport is dominated by the Schottky mechanism. For annealed structures, under low and high biasing the ohmic and Schottky mechanisms were identified as the main processes for the electrical transport. Finally, we found that both parameters, the dielectric constant and resistivity, decrease slightly after the thermal annealing. (copyright 2010 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

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

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


    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.

  9. [Study on Trace Water Influence on Electrical Properties of Insulating Oil Based on the Mid-Infrared Spectrum Analysis].

    Chen, Bin; Wu, Hong-yang; Han, Chao; Yan, Huan; Liu, Ge


    Trace water has a significant impact on the electrical performances of the insulating oil, such as the dielectric loss factor, resistivity. So there is an important significance to investigate the influence of insulating oil by trace water, and monitor its operating status with effective measures. First, it is necessary to prepare the insulating oil samples with different water content and treat them 8 hours with ultrasonic oscillator, and observe microscopic images about the water-oil mixtures in order to study their relative uniformity and stable time, in the way it can be concluded that the relative uniformity can be kept favorable during the 25 min stable time for free water and emulsification water in oil; Based on this conclusion, the dielectric loss factor, resistivity were tested and the electrical performances of insulating oil with different water content in oil can obtained by analyzing these data; Then, the absorbance value of the different water content in oil at the spectral wave number of 1 640, 3 400, 3 450, 3 615 cm(-1), with the mid-infrared spectral scanning and analyzing to the different water content in oil, Therefore, combined the water absorbance values by the mid-infrared spectral scanning and analyzing with the experimental data of dielectric loss factor value, resistivity value of oil samples. The results shows that the absorbance value of the different water content in oil has a significant difference at the spectral wave number of 1 640, 3 400, 3450, 3 615 cm(-1), their correlation coefficient are 0.964 1, 0.984 8, 0.984 5, 0.944 0 between the absorbance value and water content at the spectral wave number of 1 640, 3 400, 3 450, 3 615 cm(-1), it can be obtained that the absorbance value of sample of moisture in the corresponding characteristic wave number can better reflect the change trend of water content; there is the highly relative of water absorbance values at the spectral wave number of 3 400 and 3 450 cm(-1) with the trends of

  10. Electrical Detection of the Helical Spin Texture in a p-type Topological Insulator Sb2Te3

    Li, C. H.; van ‘T Erve, O. M. J.; Li, Y. Y.; Li, L.; Jonker, B. T.


    The surface states of 3D topological insulators (TIs) exhibit a helical spin texture with spin locked at right angles with momentum. The chirality of this spin texture is expected to invert crossing the Dirac point, a property that has been experimentally observed by optical probes. Here, we directly determine the chirality below the Dirac point by electrically detecting spin-momentum locking in surface states of a p-type TI, Sb2Te3. A current flowing in the Sb2Te3 surface states generates a net spin polarization due to spin-momentum locking, which is electrically detected as a voltage on an Fe/Al2O3 tunnel barrier detector. Measurements of this voltage as a function of current direction and detector magnetization indicate that hole spin-momentum locking follows the right-hand rule, opposite that of electron, providing direct confirmation that the chirality is indeed inverted below Dirac point. The spin signal is linear with current, and exhibits a temperature dependence consistent with the semiconducting nature of the TI film and freeze-out of bulk conduction below 100 K. Our results demonstrate that the chirality of the helical spin texture of TI surface states can be determined electrically, an enabling step in the electrical manipulation of spins in next generation TI-based quantum devices.

  11. Dynamical interplay between fluctuations, electric fields and transport in fusion plasmas

    C Hidalgo; B Gonçalves; M A Pedrosa


    A view of recent experimental results and progress in the characterization of the statistical properties of electrostatic turbulence in magnetically confined devices is given. An empirical similarity in the scaling properties of the probability distribution function (PDF) of turbulent transport has been observed in the plasma edge region in fusion plasmas. The investigation of the dynamical interplay between fluctuation in gradients, turbulent transport and radial electric fields has shown that these parameters are strongly coupled both in tokamak and stellarator plasmas. The bursty behaviour of turbulent transport is linked with a departure from the most probable radial gradient. The dynamical relation between fluctuations in gradients and transport is strongly affected by the presence of sheared poloidal flows which organized themselves near marginal stability. These results emphasize the importance of the statistical description of transport processes in fusion plasmas as an alternative approach to the traditional way to characterize transport based on the computation of effective transport coefficients.

  12. A Multiple Data Fusion Approach to Wheel Slip Control for Decentralized Electric Vehicles

    Dejun Yin


    Full Text Available Currently, active safety control methods for cars, i.e., the antilock braking system (ABS, the traction control system (TCS, and electronic stability control (ESC, govern the wheel slip control based on the wheel slip ratio, which relies on the information from non-driven wheels. However, these methods are not applicable in the cases without non-driven wheels, e.g., a four-wheel decentralized electric vehicle. Therefore, this paper proposes a new wheel slip control approach based on a novel data fusion method to ensure good traction performance in any driving condition. Firstly, with the proposed data fusion algorithm, the acceleration estimator makes use of the data measured by the sensor installed near the vehicle center of mass (CM to calculate the reference acceleration of each wheel center. Then, the wheel slip is constrained by controlling the acceleration deviation between the actual wheel and the reference wheel center. By comparison with non-control and model following control (MFC cases in double lane change tests, the simulation results demonstrate that the proposed control method has significant anti-slip effectiveness and stabilizing control performance.

  13. The characteristics of electrical trees in the inner and outer layers of different voltage rating XLPE cable insulation

    Xie, Ansheng; Li, Shengtao; Zheng, Xiaoquan; Chen, George


    The statistical initiation and propagation characteristics of electrical trees in cross-linked polyethylene (XLPE) cables with different voltage ratings from 66 to 500 kV were investigated under a constant test voltage of 50 Hz/7 kV (the 66 kV rating cable is from UK, the others from China). It was found that the characteristics of electrical trees in the inner region of 66 kV cable insulation differed considerably from those in the outer region under the same test conditions; however, no significant differences appeared in the 110 kV rating cable and above. The initiation time of electrical trees in both the inner and the outer regions of the 66 kV cable is much shorter than that in higher voltage rating cables; in addition the growth rate of electrical trees in the 66 kV cable is much larger than that in the higher voltage rating cables. By using x-ray diffraction, differential scanning calorimetry and thermogravimetry methods, it was revealed that besides the extrusion process, the molecular weight of base polymer material and its distribution are the prime factors deciding the crystallization state. The crystallization state and the impurity content are responsible for the resistance to electrical trees. Furthermore, it was proposed that big spherulites will cooperate with high impurity content in enhancing the initiation and growth processes of electrical trees via the 'synergetic effect'. Finally, dense and small spherulites, high crystallinity, high purity level of base polymer material and super-clean production processes are desirable for higher voltage rating cables.

  14. The characteristics of electrical trees in the inner and outer layers of different voltage rating XLPE cable insulation

    Xie Ansheng; Li Shengtao; Zheng Xiaoquan [State Key Laboratory of Electrical Insulation and Power Equipment, Xi' an Jiaotong University, Xi' an 710049 (China); Chen, George, E-mail:, E-mail:, E-mail:, E-mail: [School of Electronics and Computer Science, University of Southampton, Southampton SO17 1BJ (United Kingdom)


    The statistical initiation and propagation characteristics of electrical trees in cross-linked polyethylene (XLPE) cables with different voltage ratings from 66 to 500 kV were investigated under a constant test voltage of 50 Hz/7 kV (the 66 kV rating cable is from UK, the others from China). It was found that the characteristics of electrical trees in the inner region of 66 kV cable insulation differed considerably from those in the outer region under the same test conditions; however, no significant differences appeared in the 110 kV rating cable and above. The initiation time of electrical trees in both the inner and the outer regions of the 66 kV cable is much shorter than that in higher voltage rating cables; in addition the growth rate of electrical trees in the 66 kV cable is much larger than that in the higher voltage rating cables. By using x-ray diffraction, differential scanning calorimetry and thermogravimetry methods, it was revealed that besides the extrusion process, the molecular weight of base polymer material and its distribution are the prime factors deciding the crystallization state. The crystallization state and the impurity content are responsible for the resistance to electrical trees. Furthermore, it was proposed that big spherulites will cooperate with high impurity content in enhancing the initiation and growth processes of electrical trees via the 'synergetic effect'. Finally, dense and small spherulites, high crystallinity, high purity level of base polymer material and super-clean production processes are desirable for higher voltage rating cables.

  15. Poster — Thur Eve — 09: Evaluation of electrical impedance and computed tomography fusion algorithms using an anthropomorphic phantom

    Chugh, Brige Paul; Krishnan, Kalpagam; Liu, Jeff; Kohli, Kirpal [BC Cancer Agency — Fraser Valley Centre (Canada)


    Integration of biological conductivity information provided by Electrical Impedance Tomography (EIT) with anatomical information provided by Computed Tomography (CT) imaging could improve the ability to characterize tissues in clinical applications. In this paper, we report results of our study which compared the fusion of EIT with CT using three different image fusion algorithms, namely: weighted averaging, wavelet fusion, and ROI indexing. The ROI indexing method of fusion involves segmenting the regions of interest from the CT image and replacing the pixels with the pixels of the EIT image. The three algorithms were applied to a CT and EIT image of an anthropomorphic phantom, constructed out of five acrylic contrast targets with varying diameter embedded in a base of gelatin bolus. The imaging performance was assessed using Detectability and Structural Similarity Index Measure (SSIM). Wavelet fusion and ROI-indexing resulted in lower Detectability (by 35% and 47%, respectively) yet higher SSIM (by 66% and 73%, respectively) than weighted averaging. Our results suggest that wavelet fusion and ROI-indexing yielded more consistent and optimal fusion performance than weighted averaging.

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

    Lim, Seungjae


    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.

  17. Pressure evolution of electrical transport in the 3D topological insulator (Bi,Sb)2(Se,Te)3

    Jeffries, J. R.; Butch, N. P.; Vohra, Y. K.; Weir, S. T.


    The group V-VI compounds—like Bi2Se3, Sb2Te3, or Bi2Te3—have been widely studied in recent years for their bulk topological properties. The high-Z members of this series form with the same crystal structure, and are therefore amenable to isostructural substitution studies. It is possible to tune the Bi-Sb and Te-Se ratios such that the material exhibits insulating behavior, thus providing an excellent platform for understanding how a topological insulator evolves with applied pressure. We report our observations of the pressure-dependent electrical transport and crystal structure of a pseudobinary (Bi,Sb)2(Te,Se)3 compound. Similar to some of its sister compounds, the (Bi,Sb)2(Te,Se)3 pseudobinary compound undergoes multiple, pressure-induced phase transformations that result in metallization, the onset of a close-packed crystal structure, and the development of distinct superconducting phases.

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

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


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

    Tan, J. K.; Abas, N.


    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.

  20. 一种新型电动机隔声罩%The New Noise-insulation Installation of Electrical Motor



    本文介绍一种新型电动机隔声罩。其特点在于将隔声罩内腔设计成更接近轴流风机气流通道的形状,从而改善散热性能;同时也采取了更有效的降低噪声措施。试验效果良好,可供参考。%The paper describes the new noise-insulation installation of electrical motor.Its bore was designed that looked like axial fan.So that the design ameliorates its elimination of heat,and has taken effectively measures to depress noise.Experiments have obtain good effect,so you can make reference to this paper.

  1. Observation of radiation degradation of electrical insulators in the CERN particle accelerators

    Chevalier, Ch.; Coste, V.; Fontaine, A.; Tavlet, M.


    For the selection of polymer-based materials to be used in radiation environments, radiation tests have been performed at the European Organization for Particle Physics Research (CERN) for several decades. According to the recommendations of the IEC Standard 544, mechanical tests are carried out, and the radiation degradation is measured after accelerated irradiations. It is well known that during long-term exposures, oxygen and moisture are allowed to diffuse in the materials and hence to induce more severe degradation; this phenomenon is known as the `dose-rate effect'. During machine shut-downs, samples of rigid and flexible polymeric insulators (magnet-coil resins and cable insulations) have been taken out and tested after several years of exposure in the Super Proton Synchrotron (SPS) and in the Large Electron-Position Collider (LEP). The mechanical test results are compared to the ones after the accelerated qualification tests, and to the ones of a study conducted in 1991 to estimate the lifetime of cables in the radiation environment of LEP 200. They confirm that thermoplastics are more sensitive to long-term irradiations than the thermosetting resins and the composites, but that the dose-rate effect cannot be neglected in the latter.

  2. Nanoscale electric polarizability of ultrathin biolayers on insulating substrates by electrostatic force microscopy.

    Dols-Perez, A; Gramse, G; Calò, A; Gomila, G; Fumagalli, L


    We measured and quantified the local electric polarization properties of ultrathin (∼5 nm) biolayers on mm-thick mica substrates. We achieved it by scanning a sharp conductive tip (nanoscale, including nanoscale label-free composition mapping.

  3. Seismic base isolation of gas insulated electrical substations: Comparison among different solutions

    Serino, G. [Univ. di Napoli Federico II (Italy). Dipt. di Analisi e Progettazione Strutturale; Bettinali, F. [ENEL s.p.a., Milano (Italy). Centro di Ricerca Idraulica e Strutturale; Bonacina, G. [ISMES s.p.a., Seriate (Italy). Div. Indagini Strutturali


    Base isolation of an outdoor 170 kV Gas-Insulated Substation conforming to ENEL standardization is proposed. The analyzed GIS has two separated phases and its layout consists of a compact block composed of five bays and two High-to-Medium Voltage power transformers. The design has been carried out following the International Electrotechnical Commission (IEC) requirements for seismic qualification of HV equipment. Three solutions are presented, each making use of different isolation devices: High-Damping Steel-Laminated Rubber Bearings, helical springs and visco-dampers, Friction Pendulu devices. The procedures adopted in the design of the three isolation systems are briefly explained, pointing out advantages and drawbacks of each solution.

  4. Simplification Study of FE Model for 1000kV AC Transmission Line Insulator String Voltage and Grading Ring Surface Electric Field Distribution Calculation

    Guoli Wang


    Full Text Available The finite element model of the 1000kV Ultra High Voltage (UHV AC transmission line porcelain insulator string voltage distribution and grading ring surface electric field distribution calculation has the characteristics of large size, complicated structure and various mediums. To insure the accuracy, related influencing factors should be considered to simplify the model reasonably for improving computational efficiency. A whole model and a simplified 3D finite element model of UHV AC transmission line porcelain insulator string were built. The influencing factors including tower, phase conductors, hardware fittings, yoke plate and phase interaction were considered in the analysis. And finally, the rationality of the simplified model was validated. The results comparison show that building a simplified model of three-phase bundled conductors within a certain length, simplifying the tower reasonably, omitting the hardware fittings and yoke plate and containing only single-phase insulator string model is feasible. The simplified model could replace the whole model to analyze the voltage distribution along the porcelain insulator string and the electric field distribution on the grading ring surface, and it can reduce the calculation scale, improve optimization efficiency of insulators string and grading ring parameters.

  5. Temperature and electric field induced metal-insulator transition in atomic layer deposited VO2 thin films

    Tadjer, Marko J.; Wheeler, Virginia D.; Downey, Brian P.; Robinson, Zachary R.; Meyer, David J.; Eddy, Charles R.; Kub, Fritz J.


    Amorphous vanadium oxide (VO2) films deposited by atomic layer deposition (ALD) were crystallized with an ex situ anneal at 660-670 °C for 1-2 h under a low oxygen pressure (10-4 to 10-5 Torr). Under these conditions the crystalline VO2 phase was maintained, while formation of the V2O5 phase was suppressed. Electrical transition from the insulator to the metallic phase was observed in the 37-60 °C range, with an ROFF/RON ratio of up to about 750 and ΔTC ≅ 7-10 °C. Lateral electric field applied across two-terminal device structures induced a reversible phase change, with a room temperature transition field of about 25 kV/cm in the VO2 sample processed with the 2 h long O2 anneal. Both the width and slope of the field induced MIT I-V hysteresis were dependent upon the VO2 crystalline quality.

  6. Scattering of electromagnetic plane wave from a perfect electric conducting strip placed at interface of topological insulator-chiral medium

    Shoukat, Sobia; Naqvi, Qaisar A.


    In this manuscript, scattering from a perfect electric conducting strip located at planar interface of topological insulator (TI)-chiral medium is investigated using the Kobayashi Potential method. Longitudinal components of electric and magnetic vector potential in terms of unknown weighting function are considered. Use of related set of boundary conditions yields two algebraic equations and four dual integral equations (DIEs). Integrand of two DIEs are expanded in terms of the characteristic functions with expansion coefficients which must satisfy, simultaneously, the discontinuous property of the Weber-Schafheitlin integrals, required edge and boundary conditions. The resulting expressions are then combined with algebraic equations to express the weighting function in terms of expansion coefficients, these expansion coefficients are then substituted in remaining DIEs. The projection is applied using the Jacobi polynomials. This treatment yields matrix equation for expansion coefficients which is solved numerically. These unknown expansion coefficients are used to find the scattered field. The far zone scattering width is investigated with respect to different parameters of the geometry, i.e, chirality of chiral medium, angle of incidence, size of the strip. Significant effects of different parameters including TI parameter on the scattering width are noted.

  7. Electrical Characteristics of Copper Phthalocyanine Thin-Film Transistors with Polyamide-6/Polytetrafluoroethylene Gate Insulator

    YU Shun-Yang; XU Shi-Ai; MA Dong-Ge


    Polyamide-6(PA 6)/polytetrafluoroethylene is studied as a potential gate dielectric for flexible organic thin film transistors.The salne method used for the formation of organic semiconductor and gate dielectric films greatly simplifies the fabrication process of devices.The fabricated transistors show good electrical characteristics.Ambipolar behaviour is observed even when the device is operated in air.

  8. Electric breakdowns of the "plasma capacitors" occurs on insulation coating of the ISS surface

    Homin, Taras; Korsun, Anatolii

    High electric fields and currents are occurred in the spacecrafts plasma environment by onboard electric generators. Thus the high voltage solar array (SA) of the American segment of International Space Station (ISS) generates potential 160 V. Its negative pole is shorted to the frames of all the ISS segments. There is electric current between the SA and the frame through the plasma environment, i.e. electric discharge occurs. As a result a potential drop exists between the frames of all the ISS segments and the environmental plasma [1], which is cathode drop potential varphi _{c} defined. When ISS orbiting, the φc varies greatly in the range 0-100 V. A large area of the ISS frames and SA surface is coated with a thin dielectric film. Because of cathode drop potential the frame surfaces accumulate ion charges and the SA surfaces accumulate electron charges. These surfaces become plasma capacitors, which accumulate much charge and energy. Micrometeorite impacts or buildup of potential drop in excess of breakdown threshold varphi_{b} (varphi _{c} > varphi _{b} = 60 V) may cause breakdowns of these capacitors. Following a breakdown, the charge collected at the surfaces disperses and transforms into a layer of dense plasma [2]. This plasma environment of the spacecraft produces great pulsed electric fields E at the frame surfaces as well as heavy currents between construction elements which in turn induce great magnetic fields H. Therefore the conductive frame and the environmental plasma is plasma inductors. We have calculated that the densities of these pulsing and high-frequency fields E and H generated in the plasma environment of the spacecraft may exceed values hazardous to human. Besides, these fields must induce large electromagnetic impulses in the space-suit and in the power supply and control circuits of onboard systems. During astronaut’s space-suit activity, these fields will penetrate the space-suit and the human body with possible hazardous effects

  9. Very Low Frequency Breakdown Properties of Electrical Insulation Materials at Cryogenic Temperatures

    Sauers, I.; Tuncer, E.; Polizos, G.; James, D. R.; Ellis, A. R.; Pace, M. O.


    For long cables or equipment with large capacitance it is not always possible to conduct high voltage withstand tests at 60 Hz due to limitations in charging currents of the power supply. Very low frequency (typically at a frequency of 0.1 Hz) has been used for conventional cables as a way of getting around the charging current limitation. For superconducting grid applications the same issues apply. However there is very little data at cryogenic temperatures on how materials perform at low frequency compared to 60 Hz and whether higher voltages should be applied when performing a high voltage acceptability test. Various materials including G10 (fiberglass reinforced plastic or FRP), Cryoflex™ (a tape insulation used in some high temperature superconducting cables), kapton (commonly used polyimide), polycarbonate, and polyetherimide, and in liquid nitrogen alone have been tested using a step method for frequencies of 60 Hz, 0.1 Hz, and dc. The dwell time at each step was chosen so that the aging factor would be the same in both the 60 Hz and 0.1 Hz tests. The data indicated that, while there is a small frequency dependence for liquid nitrogen, there are significant differences for the solid materials studied. Breakdown data for these materials and for model cables will be shown and discussed.

  10. Serial DNA relay in DNA logic gates by electrical fusion and mechanical splitting of droplets

    Kawano, Ryuji; Takinoue, Masahiro; Osaki, Toshihisa; Kamiya, Koki; Miki, Norihisa


    DNA logic circuits utilizing DNA hybridization and/or enzymatic reactions have drawn increasing attention for their potential applications in the diagnosis and treatment of cellular diseases. The compartmentalization of such a system into a microdroplet considerably helps to precisely regulate local interactions and reactions between molecules. In this study, we introduced a relay approach for enabling the transfer of DNA from one droplet to another to implement multi-step sequential logic operations. We proposed electrical fusion and mechanical splitting of droplets to facilitate the DNA flow at the inputs, logic operation, output, and serial connection between two logic gates. We developed Negative-OR operations integrated by a serial connection of the OR gate and NOT gate incorporated in a series of droplets. The four types of input defined by the presence/absence of DNA in the input droplet pair were correctly reflected in the readout at the Negative-OR gate. The proposed approach potentially allows for serial and parallel logic operations that could be used for complex diagnostic applications. PMID:28700641

  11. Online energy management strategy of fuel cell hybrid electric vehicles based on data fusion approach

    Zhou, Daming; Al-Durra, Ahmed; Gao, Fei; Ravey, Alexandre; Matraji, Imad; Godoy Simões, Marcelo


    Energy management strategy plays a key role for Fuel Cell Hybrid Electric Vehicles (FCHEVs), it directly affects the efficiency and performance of energy storages in FCHEVs. For example, by using a suitable energy distribution controller, the fuel cell system can be maintained in a high efficiency region and thus saving hydrogen consumption. In this paper, an energy management strategy for online driving cycles is proposed based on a combination of the parameters from three offline optimized fuzzy logic controllers using data fusion approach. The fuzzy logic controllers are respectively optimized for three typical driving scenarios: highway, suburban and city in offline. To classify patterns of online driving cycles, a Probabilistic Support Vector Machine (PSVM) is used to provide probabilistic classification results. Based on the classification results of the online driving cycle, the parameters of each offline optimized fuzzy logic controllers are then fused using Dempster-Shafer (DS) evidence theory, in order to calculate the final parameters for the online fuzzy logic controller. Three experimental validations using Hardware-In-the-Loop (HIL) platform with different-sized FCHEVs have been performed. Experimental comparison results show that, the proposed PSVM-DS based online controller can achieve a relatively stable operation and a higher efficiency of fuel cell system in real driving cycles.

  12. Do clinical examination gloves provide adequate electrical insulation for safe hands-on defibrillation? I: Resistive properties of nitrile gloves.

    Deakin, Charles D; Lee-Shrewsbury, Victoria; Hogg, Kitwani; Petley, Graham W


    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.

  13. Water Tree Influence on Space Charge Distribution and on the Residual Electric Field in Polyethylene Insulation

    Cristina Stancu


    Full Text Available A computation method of the electricfield and ionic space charge density in planeinsulations with water trees (using a ComsolMultiphysics software and the thermal step currents(Im(t measured with Thermal Step Method ispresented. A parabolic spatial variation of volumecharge density, an exponential spatial variation ofthe electric permittivity ε and a linear dependency ofε and the temperature coefficient of permittivity αεwith the average water concentration in trees, areconsidered. For a water tree with a known length,different values of charge density are consideredand the electric field and the thermal step currentsIc(t are calculated. The currents Ic(t and Im(t arecompared and the volume of charge density andelectric field for which Ic(t is identical with Im(t arekept.

  14. Effect of Prestressing on the ns Range Electrical Breakdown in Polymeric Insulating Films

    Kitani, Isamu; Arii, Kiyomitsu


    The electrical impulse breakdown of prestressed polymer films was investigated in the ns range. The effect of prestressing on the breakdown was observed in polyethylene terephthalate (PET) and polycarbonate (PC), but not in polystyrene (PS) or polypropylene (PP). The amount of space charge estimated from the transient currents was large enough to induce electric field distortion in the bulk for all specimens. The effect in PET and PC is attributed to field distortion due to space charge accumulation near the electrodes, which can be estimated as electrons at the cathode and holes at the anode. The reason why the effect was not observed in PP and PS can be explained as the result of their own high breakdown strength in strong non-uniform fields.

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

    Eisel, Thomas; Bremer, J


    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...

  16. Low temperature growth and electrical characterization of insulators for GaAs MISFETS

    Borrego, J. M.; Ghandhi, S. K.


    Progress in the low temperature growth of oxides and layers on GaAs and the detailed electrical characterization of these oxides is reported. A plasma anodization system was designed, assembled, and put into operation. A measurement system was assembled for determining capacitance and conductance as a function of gate voltage for frequencies in the range from 1 Hz to 1 MHz. Initial measurements were carried out in Si-SiO2 capacitors in order to test the system and in GaAs MIS capacitors abricated using liquid anodization.

  17. Electrical and Thermal Characteristics of the Insulator-Metal Transition in Crystalline V2O5 Films

    Kang, Manil; Kim, Sok Won


    The electrical and thermal properties with respect to the crystallization in V2O5 thin films were investigated by measuring the resistance at different temperatures and applied voltages. The changes in the crystal structure of the films at different temperatures were also explored using Raman measurements. The thermal diffusivity of the crystalline V2O5 film was measured by the nanosecond thermoreflectance method. The microstructures of amorphous and crystalline V2O5 were observed by SEM and XRD measurements. The temperature-dependent Raman spectra revealed that a structural phase transition does not occur in the crystalline film. The resistance measurements of an amorphous film indicated semiconducting behavior, whereas the resistance of the crystalline film revealed a substantial change near 250 {°}C, and Ohmic behavior was observed above 380 {°}C. This result was due to the metal-insulator transition induced by lattice distortion in the crystalline film, for which Tc was 260 {°}C. Tc of the film decreased from 260 {°}C to 230 {°}C with increasing applied voltage from 0 V to 10 V. Furthermore, the thermal diffusivity of the crystalline film was 1.67× 10^{-7} m2\\cdot s^{-1} according to the nanosecond thermoreflectance measurements.

  18. Microstructural and Electrical Properties of ZrO2 Thin Films Prepared on silicon on Insulator with Thin Top silicon

    章宁琳; 宋志棠; 沈勤我; 林成鲁


    Amorphous zirconia thin films were deposited directly on silicon-on-insulator (SOI) substrates with thin top silicon by ultra-high vacuum electron beam evaporation. Spreading resistance profile and scanning transmission-electron microscopy (TEM) were used to detect the interface quality and microstructure, revealing that the interface between the zirconium oxide films and top silicon was abrupt and clear. The films kept to be amorphous up to the rapid thermal temperature of 700°C for 300s, but arriving at 700°C an unknown interfacial product appeared,which was probably ZrSixOy. High frequency capacitance-voltage (C- V) characteristics at 1 MHz performed on metal-oxide-SOI structure revealed that this interfacial product exhibited good electrical properties of zirconia thin films. When the annealing temperature increased from 600°C to 700°C, flat voltage VFB changed from -2.451 to -1.741 eV, showing the improvement in the quality of the films. The cumulative region capacitance decreased from 3.058 × 10-11F to 3.012 × 10-11F, indicating increasing equivalent oxide thickness, which is in agreement with the result of high-resolution cross-sectional TEM.

  19. Fire hazard analysis for fusion energy experiments

    Alvares, N.J.; Hasegawa, H.K.


    The 2XIIB mirror fusion facility at Lawrence Livermore Laboratory (LLL) was used to evaluate the fire safety of state-of-the-art fusion energy experiments. The primary objective of this evaluation was to ensure the parallel development of fire safety and fusion energy technology. Through fault-tree analysis, we obtained a detailed engineering description of the 2XIIB fire protection system. This information helped us establish an optimum level of fire protection for experimental fusion energy facilities as well as evaluate the level of protection provided by various systems. Concurrently, we analyzed the fire hazard inherent to the facility using techniques that relate the probability of ignition to the flame spread and heat-release potential of construction materials, electrical and thermal insulations, and dielectric fluids. A comparison of the results of both analyses revealed that the existing fire protection system should be modified to accommodate the range of fire hazards inherent to the 2XIIB facility.

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

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


    The secondary electron emission contrast between poled and unpoled regions in thermally poled Ge-doped silica films were measured according to different annealing temperatures and electron doses with electron acceleration energy of 5 keV. It is used for measuring the change on annealing of poling...... 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...

  1. Partial Discharge Characteristics of Polymer Nanocomposite Materials in Electrical Insulation: A Review of Sample Preparation Techniques, Analysis Methods, Potential Applications, and Future Trends

    Wan Akmal Izzati


    Full Text Available 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.

  2. Preparation of Poly(p-phenylene sulfi de)/Carbon Composites with Enhanced Thermal Conductivity and Electrical Insulativity via Hybrids of Boron Nitride and Carbon Fillers

    WU Jieli; WANG Jinwen; CHEN Feng


    The present work enhanced the thermal conductivity of poly(p-phenylene sulfi de)/expanded graphites and poly(p-phenylene sulfi de)/carbon nanotubes, by incorporating composites with hexagonal boron nitride, which simultaneously succeeded in raising the electrical conductivity of the systems. A two-step mechanical processing method which includes rotating solid-state premixing and inner mixing was adopted to improve dispersion of the hybrids, contributing to the formation of an interspered thermal conductive network. Similar synergic effect in thermal conductivity enhancement was discovered in the hybrid systems regardless of the dimension difference between the two carbonfi llers. Such is postulated to be the one satisfying advantage generated by the afore-mentioned network; the other is the insulativity of the hybrid systems given by the effective blockage of hexagonal boron nitride as an insulating material in our network.

  3. Thermal conductivity and dielectric properties of a TiO2-based electrical insulator for use with high temperature superconductor-based magnets

    Ishmael, S. A.; Slomski, M.; Luo, H.; White, M.; Hunt, A.; Mandzy, N.; Muth, J. F.; Nesbit, R.; Paskova, T.; Straka, W.; Schwartz, J.


    Quench protection is a remaining challenge impeding the implementation of high temperature superconductor (HTS)-based magnet applications. This is due primarily to the slow normal zone propagation velocity (NZPV) observed in Bi2Sr2CaCu2OX (Bi2212) and (RE)Ba2Cu3O7 - x (REBCO) systems. Recent computational and experimental findings reveal significant improvements in turn-to-turn NZPV, resulting in a magnet that is more stable and easier to protect through three-dimensional normal zone growth (Phillips M 2009; Ishmael S et al 2013 IEEE Trans. Appl. Supercond. 23 7201311). These improvements are achieved by replacing conventional insulation materials, such as Kapton and mullite braid, with a thin, thermally conducting, electrically-insulating ceramic oxide coating. This paper reports on the temperature-dependent thermal properties, electrical breakdown limits and microstructural characteristics of a titanium oxide (TiO2) insulation and a doped-TiO2-based proprietary insulation (doped-TiO2) shown previously to enhance quench behavior (Ishmael S et al 2013 IEEE Trans. Appl. Supercond. 23 7201311). Breakdown voltages at 77 K ranging from ˜1.5 kV to over 5 kV are reported. At 4.2 K, the TiO2 increases the thermal conductivity of polyimide by about a factor of 10. With the addition of a dopant, thermal conductivity is increased by an additional 13%, and a high temperature heat treatment increases it by nearly an additional 100%. Similar increases are observed at 77 K and room temperature. These results are understood in the context of the various microstructures observed.

  4. Experimental measurement of oil-water two-phase flow by data fusion of electrical tomography sensors and venturi tube

    Liu, Yinyan; Deng, Yuchi; Zhang, Maomao; Yu, Peining; Li, Yi


    Oil-water two-phase flows are commonly found in the production processes of the petroleum industry. Accurate online measurement of flow rates is crucial to ensure the safety and efficiency of oil exploration and production. A research team from Tsinghua University has developed an experimental apparatus for multiphase flow measurement based on an electrical capacitance tomography (ECT) sensor, an electrical resistance tomography (ERT) sensor, and a venturi tube. This work presents the phase fraction and flow rate measurements of oil-water two-phase flows based on the developed apparatus. Full-range phase fraction can be obtained by the combination of the ECT sensor and the ERT sensor. By data fusion of differential pressures measured by venturi tube and the phase fraction, the total flow rate and single-phase flow rate can be calculated. Dynamic experiments were conducted on the multiphase flow loop in horizontal and vertical pipelines and at various flow rates.

  5. Electric-field-induced intradimer charge disproportionation in the dimer-Mott insulator β'-(BEDT-TTF ) 2IC l2

    Hattori, Yuma; Iguchi, Satoshi; Sasaki, Takahiko; Iwai, Shinichiro; Taniguchi, Hiromi; Kishida, Hideo


    Raman scattering spectra of the dimer-Mott insulator β'-(BEDT-TTF ) 2IC l2 [BEDT-TTF = bis(ethylenedithio)tetrathiafulvalene] under a static electric field are investigated. The application of the electric field induces two additional Raman peaks on both sides of the original peak position of the charge-sensitive Raman mode (ν2) in the spectra. At 10 kV/cm, the original peak almost disappears and only the newly emerging peaks are observed. The emergence of these peaks indicates the field-induced charge disproportionation within the dimer. The temporal change of the Raman signals with the inversion of the electric field suggests a macroscopic domain formation of the charge-disproportionate dimers. This picture is reinforced by the direct measurement of the polarization.

  6. On the relation between deep level compensation, resistivity and electric field in semi-insulating CdTe:Cl radiation detectors

    Cola, Adriano; Farella, Isabella; Pousset, Jeremy; Valletta, Antonio


    A compensation model for semi-insulating CdTe:Cl based on a single dominant deep level 0.725 eV above the valence band is proposed. The model is corroborated by experimental evidence: resistivity measurements as a function of temperature on bulk crystals and stationary electric field distributions in Ohmic/Schottky radiation detectors, obtained by the Pockels effect. The latter are in close agreement with the numerical solutions of transport equations when considering the deep centre concentration in the range 2 - 4 × 1012 cm-3, and a compensation ratio R = 2.1, this one being consistent with an original ambipolar analysis of resistivity. More generally, the approach elucidates the role of electrical contacts and deep levels in controlling the electric fields in devices based on compensated materials.

  7. Addendum to "Switching effect and the metal-insulator transition in electric field" by A.L. Pergament et al. [J. Phys. Chem. Solids 71 (2010) 874

    Pergament, A. L.; Velichko, A. A.; Stefanovich, G. B.


    In the paper mentioned above we reported on the switching mechanism in vanadium dioxide which was shown to be based on the electronically-induced Mott insulator-to-metal transition occurring in conditions of the non-equilibrium carrier density excess in the applied electric field, and the proposed model involved the dependence of the carrier density n on electric field (the Poole-Frenkel effect), as well as the dependence of the critical electric field on n. The data on the n(T) dependence were obtained on the assumption of a temperature-independent carrier mobility μ, and the problem of n reduction at lower temperatures was not fully understood. In this Letter we revisit this problem in the light of some recent data on the μ(T) dependence for VO2. It is shown that the adjusted values of n, taking into account this μ(T), correspond to the Mott critical density within an order of magnitude.

  8. Floating insulated conductors for heating subsurface formations

    Burns, David; Goodwin, Charles R.


    A heating system for a subsurface formation includes a conduit located in a first opening in the subsurface formation. Three electrical conductors are located in the conduit. A return conductor is located inside the conduit. The return conductor is electrically coupled to the ends of the electrical conductors distal from the surface of the formation. Insulation is located inside the conduit. The insulation electrically insulates the three electrical conductors, the return conductor, and the conduit from each other.

  9. The electrical characteristics of a 4H-silicon carbide metal-insulator-semiconductor structure with Al2O3 as the gate dielectric

    Liu Li; Yang Yin-Tang; Ma Xiao-Hua


    A 4H-silicon carbide metal-insulator-semiconductor structure with ultra-thin Al2O3 as the gate dielectric,deposited by atomic layer deposition on the epitaxial layer of a 4H-SiC (0001) 8(0)N-/N+ substrate,has been fabricated.The experimental results indicate that the prepared ultra-thin Al2O3 gate dielectric exhibits good physical and electrical characteristics,including a high breakdown electrical field of 25 MV/cm,excellent interface properties (1 × 1014 cm-2)and low gate-leakage current (IG =1 × 10-3 A/cm-2(o)Eox =8 MV/cm).Analysis of the current conduction mechanism on the deposited Al2O3 gate dielectric was also systematically performed.The confirmed conduction mechanisms consisted of Fowler-Nordheim (FN) tunneling,the Frenkel-Poole mechanism,direct tunneling and Schottky emission,and the dominant current conduction mechanism depends on the applied electrical field.When the gate leakage current mechanism is dominated by FN tunneling,the barrier height of SiC/Al2O3 is 1.4 eV,which can meet the requirements of silicon carbide metal-insulator-semiconductor transistor devices.

  10. Determining insulation condition of 110kV instrument transformers. Linking PD measurement results from both gas chromatography and electrical method

    Dan, C.; Morar, R.


    Working methods for on site testing of insulations: Gas chromatography (using the TFGA-P200 chromatographer); Electrical measurements of partial discharge levels using the digital detection, recording, analysis and partial discharge acquisition system, MPD600. First performed, between 2000-2015, were the chromatographic analyses concerning electrical insulating environments of: 102 current transformers, 110kV. Items in operation, functioning in 110/20kV substations. 38 voltage transformers, 110kV also in operation, functioning in 110/20kV substations. Then, electrical measurements of partial discharge inside instrument transformers, on site (power substations) were made (starting in the year 2009, over a 7-year period, collecting data until the year 2015) according to the provisions of standard EN 61869-1:2007 „Instrument transformers. General requirements”, applying, assimilated to it, type A partial discharge test procedure, using as test voltage the very rated 110kV distribution grid voltage. Given the results of two parallel measurements, containing: to this type of failure specific gas amount (H 2) and the quantitative partial discharge’ level, establishing a clear dependence between the quantity of partial discharges and the type and amount of in oil dissolved gases inside equipments affected by this type of defect: partial discharges, was expected. Of the „population” of instrument transformers subject of the two parallel measurements, the dependency between Q IEC (apparent charge) and (H 2) (hydrogen, gas amount dissolved within their insulating environment) represents a finite assemblage situated between the two limits developed on an empirical basis.

  11. Electrical and proximity-magnetic effects induced quantum Goos–Hänchen shift on the surface of topological insulator

    Kuai, Jian [School of Physics and Electronics, Yancheng Teachers College, Yancheng, 224002 Jiangsu (China); Da, H.X., E-mail: [Electrical and Computer Engineering Department, National University of Singapore, 4 Engineering Drive 3, 117576 (Singapore)


    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.

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

    Ghoneim, Mohamed T.


    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.

  13. Analysis Code for High Gradient Dielectric Insulator Surface Breakdown

    Ives, Robert Lawrence [Calabazas Creek Research, Inc.; Verboncoeur, John [University of California - Berkeley; Aldan, Manuel [University of California, Berkeley


    High voltage (HV) insulators are critical components in high-energy, accelerator and pulsed power systems that drive diverse applications in the national security, nuclear weapons science, defense and industrial arenas. In these systems, the insulator may separate vacuum/non-vacuum regions or conductors with high electrical field gradients. These insulators will often fail at electric fields over an order of magnitude lower than their intrinsic dielectric strength due to flashover at the dielectric interface. Decades of studies have produced a wealth of information on fundamental processes and mechanisms important for flashover initiation, but only for relatively simple insulator configurations in controlled environments. Accelerator and pulsed power system designers are faced with applying the fundamental knowledge to complex, operational devices with escalating HV requirements. Designers are forced to rely on “best practices” and expensive prototype testing, providing boundaries for successful operation. However, the safety margin is difficult to estimate, and system design must be very conservative for situations where testing is not practicable, or replacement of failed parts is disruptive or expensive. The Phase I program demonstrated the feasibility of developing an advanced code for modeling insulator breakdown. Such a code would be of great interest for a number of applications, including high energy physics, microwave source development, fusion sciences, and other research and industrial applications using high voltage devices.

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

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


    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 Nb3Sn 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- (9.6±5...

  15. Testing to evaluate synergistic effects from LOCA environments. Test IX. Simultaneous mode; cables, splice assemblies, and electrical insulation samples

    Thome, F.V.


    This test was conducted to complement Test VIII which was a sequential test of cables, cable splices, and insulation samples. In this test, the generic LOCA environments (radiation, temperature, pressure, chemical spray) were simulated and simultaneously applied to the test items. There were no failures of any assemblies and all were able to function at rated current and voltage throughout the entire test. An additional parameter, dissipation factor, was monitored in this test and when used in conjunction with capacitance, provided a better indication of insulation degradation.

  16. Studies of breakeven prices and electricity supply potentials of nuclear fusion by a long-term world energy and environment model

    Tokimatsu, K.; Asaoka, Y.; Konishi, S.; Fujino, J.; Ogawa, Y.; Okano, K.; Nishio, S.; Yoshida, T.; Hiwatari, R.; Yamaji, K.


    In response to social demand, this paper investigates the breakeven price (BP) and potential electricity supply of nuclear fusion energy in the 21st century by means of a world energy and environment model. We set the following objectives in this paper: (i) to reveal the economics of the introduction conditions of nuclear fusion; (ii) to know when tokamak-type nuclear fusion reactors are expected to be introduced cost-effectively into future energy systems; (iii) to estimate the share in 2100 of electricity produced by the presently designed reactors that could be economically selected in the year. The model can give in detail the energy and environment technologies and price-induced energy saving, and can illustrate optimal energy supply structures by minimizing the costs of total discounted energy systems at a discount rate of 5%. The following parameters of nuclear fusion were considered: cost of electricity (COE) in the nuclear fusion introduction year, annual COE reduction rates, regional introduction year, and regional nuclear fusion capacity projection. The investigations are carried out for three nuclear fusion projections one of which includes tritium breeding constraints, four future CO2 concentration constraints, and technological assumptions on fossil fuels, nuclear fission, CO2 sequestration, and anonymous innovative technologies. It is concluded that: (1) the BPs are from 65 to 125 mill kW-1 h-1 depending on the introduction year of nuclear fusion under the 550 ppmv CO2 concentration constraints; those of a business-as-usual (BAU) case are from 51 to 68 mill kW-1h-1. Uncertainties resulting from the CO2 concentration constraints and the technological options influenced the BPs by plus/minus some 10 30 mill kW-1h-1, (2) tokamak-type nuclear fusion reactors (as presently designed, with a COE range around 70 130 mill kW-1h-1) would be favourably introduced into energy systems after 2060 based on the economic criteria under the 450 and 550 ppmv CO2

  17. Characterization of ceramic electrical insulators discarded by the electricity distribution networks and compared with similar products without use; Caracterizacao dos isoladores eletricos ceramicos descartados pelas redes de distribuicao de eletricidade e comparacao com produtos similares sem uso

    Franco, C.S.; Mantovani, V.A.; Favero, M. [Universidade Estadual Julio de Mesquisa Filho (UNESP), Sorocaba, SP (Brazil); Morales, J.; Hasegawa, H.L. [2-Universidade de Sorocaba (UNISO), SP (Brazil)


    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)

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

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


    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...

  19. A new experimental approach for characterizing the internal trapped charge and electric field build up in ground-coated insulators during their e sup - irradiation

    Jbara, O; Belhaj, M; Cazaux, J; Rau, E I; Filippov, M; Andrianov, M V


    An original method is proposed to investigate the dynamical trapping properties of bulk insulators during their irradiation by keV electrons when they are coated with a grounded metallic film. This method is based on the measurement of the displacement current and it allows to evaluate time constants for charging and discharging the dielectric as well as to evaluate the electric field build up and trapped charge density below the coating. This method is illustrated by the estimate of the charging and discharging time constants in e sup - irradiated PMMA and the estimate of the magnitude of the electric field which drives the migration of the mobile ions in e sup - irradiated glasses.

  20. Potential and electric-field distributions around an ice-covered post-type insulator; Distributions du potentiel et du champ electrique le long d'un isolateur de poste recouvert de glace

    Volat, C.; Farzaneh, M. [Quebec Univ., Chicoutimi, PQ (Canada). Industrial Chair on Atmospheric Icing of Power Network Equipment


    This study investigated the phenomenon preceding a flashover on an ice-covered post-type insulator during a melting period. The potential and electric-field distributions along the insulator were calculated in an effort to solve the problem of power outages in cold, remote regions and to find the location of faulty equipment during icing events. It was shown that ice accumulation can significantly affect the performance of electrical insulators and that new and better insulators should be considered for cold climate regions. This study included a laboratory component in which an ice-covered insulator was simulated and experimentally validated using a commercial software based on the boundary element method. The simulation considered the presence of a conducting water film at the ice surface, the shedding of ice deposits, and the presence of a partial electric arc along an air gap. It was concluded that the water film, the number of internal voids, and the duration and presence of partial arcs has a considerable influence on the insulators. 22 refs., 7 tabs., 16 figs.

  1. Magnetic and electrical response of Co-doped La0.7Ca0.3MnO3 manganites/insulator system

    Debnath, J. C.; Wang, Jianli


    We present a systematic study of the structural, magnetic and electrical properties of La0.7Ca0.3MnO3 (LCMO) and La0.7Ca0.3Mn0.95Co0.05O3 (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=ρ0 +ρ2⊡5Τ2⊡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.

  2. Insulation fact sheet



    Electricity bills, oil bills, gas bills - all homeowners pay for one or more of these utilities, and wish they paid less. Often many of us do not really know how to control or reduce our utility bills. We resign ourselves to high bills because we think that is the price we have to pay for a comfortable home. We encourage our children to turn off the lights and appliances, but may not recognize the benefits of insulating the attic. This publication provides facts relative to home insulation. It discusses where to insulate, what products to use, the decision making process, installation options, and sources of additional information.

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

    Simon, N.J.


    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{sup 7} to 10{sup 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{sup 23}/m{sup 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 {sup 10}B + n {yields} {sup 7}Li + {alpha} reaction occurred near the glass-epoxy interface. This problem can easily be avoided by substituting B-free glass (R, S, or T types).

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

    Langeslag, S. A. E.; Rodriguez Castro, E.; Aviles Santillana, I.; Sgobba, S.; Foussat, A.


    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 insulation breaks. A binary test setup is proposed, where mechanical failure is assumed when leak rate of gaseous helium exceeds 10-9·Pa·m3/s. The test consists of a load-to-failure insulation break charging, in tension, while immersed in liquid nitrogen at the temperature of 77 K. Leak tightness during the test is monitored by measuring the leak rate of the gaseous helium, directly surrounding the insulation break, with respect to the existing vacuum inside the insulation break. The experimental setup is proven effective, and various insulation breaks performed beyond expectations.

  5. Electrical insulating materials - Determination of the effects of ionizing radiation - Part 5: Procedures for assessment of ageing in service

    International Electrotechnical Commission. Geneva


    Covers ageing assessment methods which can be applied to components based on polymeric materials (for example, cable insulation and jackets, elastomeric seals, polymeric coatings, gaiters) which are used in environments where they are exposed to radiation. The object of this part of IEC 60544 is to provide guidelines on the assessment of ageing in service. The approaches discussed cover ageing assessment programmes based on condition monitoring (CM), the use of equipment deposits in severe environments and sampling of real-time aged components.

  6. Influence of turn-to-turn resistivity and coil geometrical size on charging characteristics of no-electrical-insulation REBCO pancake coils

    Wang, Y.; Song, H.


    High temperature superconductor (HTS) no-electrical-insulation (NEI) coils demonstrate great advantages in thermal stability and self-protection features. However, an intrinsic delay is observed in the charging process and as a result there maybe a possible settle-out problem. It becomes more critical for large HTS coils with more turns, such as the magnets for the accelerator system and DC induction heater applications. This paper presents detailed studies on the charging characteristics of NEI coils. Firstly, two different no-electrical-insulation coils are wound: the first is directly wound using only REBCO tapes with brass lamination, which is called a no-insulation (NI) coil. The other one is co-wound with stainless steel (SS) strips and REBCO tapes whose copper stabilizer is electroplated, which is called a metallic insulation (MI) coil. Fast discharging tests are performed on the two coils and their equivalent turn-to-turn resistivity is calculated. A similar discharging delay is observed on both coils, but the turn-to-turn resistivity of the SS co-wound coil is much higher than that of the first coil. Then the resistivity data is directly applied to an equivalent circuit network model which is developed to predict the charging behaviours. The model calculates coil voltage, currents along the azimuthal and radial directions, as well as the induced magnetic field. A practical charging time is defined to characterize the field ramping process considering the charging delay between field ramping and current charging. The charging behaviours are extensively analyzed and compared in terms of three primary factors: equivalent turn-to-turn resistivity, coil size and ramping rate. The results show that the charging time increases dramatically with the coil size and may be too long to be practical for large-scale applications using HTS coils with low turn-to-turn resistivity. Increasing the turn-to-turn resistivity enables one to accelerate the charging process

  7. Facile Exfoliation and Noncovalent Superacid Functionalization of Boron Nitride Nanosheets and Their Use for Highly Thermally Conductive and Electrically Insulating Polymer Nanocomposites.

    Morishita, Takuya; Okamoto, Hirotaka


    There is an increasing demand for highly thermally conductive and electrically insulating polymer materials for next-generation electronic devices, power systems, and communication equipment. Boron nitride nanosheets (BNNSs) are insulating materials with extremely high thermal conductivity. However, BNNSs suffer from the lack of facile and low-cost methods for producing large volumes of BNNSs, and extremely low through-plane thermal conductivities of BNNS/polymer composites as compared to the in-plane thermal conductivities. Herein, highly soluble, noncovalently functionalized boron nitride nanosheets (NF-BNNSs) with chlorosulfonic acid (CSA) were prepared by extremely facile and low-cost direct exfoliation of hexagonal boron nitrides (h-BNs), and acted as excellent nanofillers for dramatically improving both in- and through-plane thermal conductivities of insulating polymers. CSA is a cheap and versatile superacid with a large production volume. CSA showed strong physical adsorption on h-BN surfaces, giving few-layered NF-BNNSs in high yields (up to ∼25%). The crystallinity of the NF-BNNS was perfectly maintained even after CSA treatment. The physical adsorption of CSAs imparted high solubility for BNNSs in various organic solvents, yielding NF-BNNS uniformly dispersed-thermoplastic polymer composite films through a simple wet-process using predispersed NF-BNNS solutions. Random dispersion of NF-BNNSs in thermoplastic polymer films dramatically enhanced both the in- and through-plane thermal conductivities (>10 W m(-1) K(-1)). The through-plane thermal conductivity of the NF-BNNS/polybutylene terephthalate (PBT) composite films was much greater (up to 11.0 W m(-1) K(-1)) than those previously reported for BNNS/thermoplastic polymer composites (≤2.6 W m(-1) K(-1)). These results are also due to an increase of interactions between the BNNS and polymer matrices, caused by physical adsorption of CSAs on BNNS surfaces. Moreover, the volume resistivity of the NF

  8. Electric Field Optimization in 170 kV Gas-Insulated Switchgear Spacer based on Non-Uniform Rational B-spline Curve

    Han, In Su; Kim, Eung Sik; Min, Suk Won; Hur, Don; Park, Jong Keun


    In this paper, the electric field at the spacer in a 170 kV gas-insulated switchgear (GIS) is optimized. Initially, the tangential and total electric fields around the original shape of the 170 kV GIS produced by a Korean company are calculated using a combination of the charge simulation method (CSM) and surface charge method (SCM). The contour of the spacer in the 170 kV GIS is found using a non-uniform rational B-spline (NURB) curve the effectiveness of which has been proved. By moving some control points in the NURB curve, the initial shape of the 170 kV GIS can be determined so that we may begin to optimize the electric field. Owing to the proposed algorithm, the overall process has a stable convergence. The objects that we want to design are the upper and lower parts of the spacer. Finally, we can find the shapes in which the tangential and total electric fields are optimized.

  9. Summary of the IEA workshop on radiation effects in ceramic insulators

    Zinkle, S.J. [Oak Ridge National Lab., TN (United States)


    A brief summary is given of research on radiation effects in ceramic insulators for fusion energy application performed during the last two years in Europe, Canada, Japan, the Russian Federation, the Ukraine and the United States. The IEA round-robin radiation induced electrical degradation (RIED) experiment on Wesgo AL995 polycrystalline alumina has been completed by 5 research groups, with none of the groups observing clear indications of REID.

  10. High performance thin film transistor (flex-TFT) with textured nanostructure ZnO film channel fabricated by exploiting electric double layer gate insulator

    Ghimire, Rishi Ram; Raychaudhuri, A. K.


    We report a flexible thin film transistor (flex-TFT) fabricated on a commonly available polyimide (Kapton®) tape with a channel of highly textured nanocrystalline ZnO film grown by pulsed laser deposition. The flex-TFT with an electric double layer (EDL) gate insulator shows a low threshold for operation (Vth ≤ 1 V), an ON/OFF ratio reaching ≈107 and a subthreshold swing ≈75 mV/dec. The superior performance is enabled by a high saturation mobility (μs ≈ 70 cm2/V s) of the highly textured nanocrystalline channel. The low Vth arises from large charge density (≈1014/cm2) induced into the channel by EDL gate insulator. The large charge density induced by the EDL gate dielectric also enhances the Hall mobility in the film and brings down the sheet resistance by nearly 2 orders, which leads to large ON/OFF ratio. The flex-TFT operation can be sustained with reproducibility when the TFT is bent down to a radius of curvature ≈2 cm.

  11. The influence of strong electric fields on the DC conductivity of the composite cellulose, insulating oil, and water nanoparticles

    Kierczyński, Konrad; Żukowski, Paweł


    The paper presents investigated the dependencies of DC conductivity electrical pressboard impregnated insolating oil of moisture content and electric field strength. The studies were conducted for measuring temperature in the range of 20 °C to 80 °C and the electric field intensity in the range of 10 kV/m to 1000 kV/m. With approximate waveforms in double logarithmic coordinates conductivity depending on the intensity of the electric field exponential function determined coefficients of determination R2. The value of this ratio is close to unity, which provides high accuracy measurements of conductivity and the exact stability and temperature measurements. It was found that changes in the electric field intensity will decrease the activation energy of conductivity of about 0.01 eV, thus increasing the DC conductivity of about 1.5 times.

  12. Applying Improved Electrical Breakdown Model to Study Insulating Property of c-C4F8/N2 Gas Mixture%Applying Improved Electrical Breakdown Model to Study Insulating Property of c-C4F8/N2Gas Mixture

    LI Xue-wen; XIAO Deng-ming


    Perfluorocyclobutane(c-C4F8) has been recently considered as a potential alternative to SF6,because of its high electro-negativity and extremely low environmental effect.However,due to its high boiling point,c-C4F8 should mixed with buffer gases such as N2 or CO2 in order to avoid the liquefaction at low temperature.This paper investigates insulating properties of c-C4F8/N2 gas mixtures from two aspects including electrical strength,and Global Warming Potential(GWP).Moreover,improved electrical breakdown model of gas mixtures is founded.Breakdown temperature and breakdown electrical field in gas mixtures can be obtained from rigorous Townsend criterion expression according to gas mixtures ratio and cross section data of gas mixtures in this model.Under the condition of different gas pressure (0.1~0.4 Mpa),gas mixtures ratio(0~30%),and electrode gap(2~10 mm),breakdown voltages of gas mixtures are calculated by using of this model.Insulation strength of SF6/N2 mixed gas is compared with c-C4F8/N2 mixed gas in the same conditions.Research results show that theoretical computation corresponds with experiment.If the content of c-C4F8 or SF6 in mixtures is less than 30%,insulation strength between c-C4F8/N2 and SF6/N2 is very close.Considering two indexes (breakdown voltage,GWP),it is suitable for c-C4F8 content being 15%~20% in c-C4F8/N2 gas mixtures.

  13. Outgassing measurements for the turn insulation of CFETR poloidal field coils

    Zou, C.; Song, Y.; Wu, H., E-mail:; Shen, G.; Wu, W.; Lu, K.; Wei, J.


    Highlights: • Outgassing rate of turn insulation will affect VPI process and conductor leak test. • The outgassing rate of turn insulation structure was measured by dynamic flow method. • The interleaved polyimide decreases the insulation outgassing rate. - Abstract: China Fusion Engineering Test Reactor (CFETR) is a new tokamak device. The poloidal field (PF) system plays an important role in controlling the location and shape of the plasma. In order to satisfy the electrical and mechanical requirements, the turn insulation shall be applied on the conductor during winding. Before vacuum pressure impregnation (VPI) process, the conductor with dry (un-impregnated) insulation should be leak tested in a chamber, and the material shall be degassed in the VPI mold before impregnation with epoxy. The gas released from the insulation material will affect the vacuum of leak test vessel and VPI quality. In this paper, the dynamic flow method was used to measure the outgassing rate of insulation material in special structure, and the results were shown and discussed.

  14. Development of coatings for fusion power applications

    Smith, D.L. E-mail:; Konys, J.; Muroga, T.; Evitkhin, V


    Coatings have been proposed as the solution to critical materials constraints for most of the blanket concepts under development for fusion power applications. However, the international programs on coating development are focused primarily on electrically insulating coatings to mitigate the magneto-hydrodynamic pressure drop in self-cooled lithium/vanadium blanket concepts, and on tritium permeation barriers to reduce tritium permeation from Pb-Li into the water coolant in water-cooled Pb-Li concepts. Emphasis of the insulator coating development is on CaO and AlN coatings formed on vanadium alloys either in situ in lithium or by vapor deposition processes. The tritium barrier coating development is focused on Al{sub 2}O{sub 3} formed on aluminized martensitic steels by several processes. This paper presents an overview of the fundamental materials issues associated with the various coatings and the status of coating development for the various applications.

  15. Suppression of metal-insulator transition in VO2 by electric field-induced oxygen vacancy formation

    Jeong, Jaewoo; Aetukuri, Nagaphani; Graf, Tanja; Schladt, Thomas D; Samant, Mahesh G; Parkin, Stuart S P


    .... We found that electrolyte gating of VO(2) leads not to electrostatically induced carriers but instead to the electric field-induced creation of oxygen vacancies, with consequent migration of oxygen from the oxide film into the ionic liquid...

  16. A Fusion of Sensors Information for Autonomous Driving Control of an Electric Vehicle (EV)

    Haris, Hasri; Wan, Khairunizam; Hazry, D.; Razlan, Zuradzman M.


    The study uses the environment of the road as input variables for the main system to control steering wheel, brake and acceleration pedals. A camera is installed on the roof of the Electric Vehicles (EV) and is used to obtain image information of the road. On the other hand, users or drivers do not have to directly contact with the main system because it will autonomously control the devices by using fuzzy information of the road conditions. A fuzzy information means in the preliminary experiments, reasoning of the various environments will be done by using fuzzy approach. At the end of the study, several existing algorithms for controlling motors and image processing technique could be combined into an algorithm that could be used to move EV without assist from human.

  17. Surface-step defect in three-dimensional topological insulators: Electric manipulation of spin and quantum spin Hall effect

    Zhou, Yan-Feng; Guo, Ai-Min; Sun, Qing-Feng


    We study the influence of a step defect on surface states in three-dimensional topological insulators subject to a perpendicular magnetic field. By calculating the energy spectrum of the surface states, we find that Landau levels (LLs) can form on flat regions of the surface and are distant from the step defect, and several subbands emerge at the side surface of the step defect. The subband which connects to the two zeroth LLs is spin polarized and chiral. In particular, when the electron transports along the side surface, the electron spin direction can be manipulated arbitrarily by gate voltage. Also, no reflection occurs even if the electron spin direction is changed. This provides a fascinating avenue to control the electron spin easily and coherently. In addition, regarding the subbands with a high LL index, there exist spin-momentum locking helical states and the quantum spin Hall effect can appear.

  18. F级高压电机环保型VPI整浸绝缘结构研究%Environmental-friendly VPI Insulation Structure of Grade F High Voltage Electric Motor

    刘晨阳; 尹默


    针对国内普通高压电机(6 kV以上)绝缘结构配套的无溶剂绝缘漆在绕组制造过程中产生大量污染环境的挥发性气体,绝缘结构单边绝缘厚度较厚,浪费能源等缺点,采用两家公司生产的绝缘漆进行实验分析,研制出一种新型绝缘结构.结果表明:该新型绝缘结构性价比高,每年能节约可观的电能,还可减少2万多吨CO2排放量.%In view of the disadvantages that the solvent-free insulating varnish for domestic common high voltage electric motor(6 kV) generates large amount of volatile gas during winding process, the structure insulation layer is thick and energy waste, a new insulation structure was developed based on analysis of insulating varnishes. The results show that the insulation structure has a high performance-price ratio, which can save considerable electric energy every year and reduce the emission of CO2 for more than 20, 000 tons/year.

  19. Efeitos da poluição atmosférica (litorânea e industrial em isoladores da rede elétrica da região metropolitana de Salvador Atmosferic pollution (coastal and industrial effects on electric energy distribution insulators in Salvador, Brazil, metropolitan region

    Kleber Franke Portella


    Full Text Available The performances of eight kinds of insulators from electrical distribution lines in Salvador-BA, Brazil, were evaluated considering the chemical and physical local environmental pollution. The parameters that were chosen as characteristic for the insulators' properties were leakage current and partial electrical discharge. A data storage processing system and a communication link to the lab were built for data acquisition. The results show that the main contribution to the poor performance of the insulators is settleable magnetite particulate matter on the insulator in addition to the long term wetness time, t4.

  20. The impact of etched trenches geometry and dielectric material on the electrical behaviour of silicon-on-insulator self-switching diodes

    Farhi, G; Charlebois, S A [Departement de genie electrique et genie informatique, et Institut interdisciplinaire d' innovation technologique (3IT), Universite de Sherbrooke, 2500, Boulevard de l' Universite, J1K 2R1, Sherbrooke, QC (Canada); Morris, D [Departement de physique et Institut interdisciplinaire d' innovation technologique (3IT), Universite de Sherbrooke, 2500, Boulevard de l' Universite, J1K 2R1, Sherbrooke, QC (Canada); Raskin, J-P, E-mail: [Institute of Information and Communication Technologies, Electronics and Applied Mathematics (ICTEAM), Universite catholique de Louvain, Place du Levant, 3, B-1348 Louvain-la-Neuve (Belgium)


    Hole electrical transport in a p-doped nanochannel defined between two L-shape etched trenches made on a silicon-on-insulator substrate is investigated using a TCAD-Medici simulator. We study the impact of the etched trenches' geometry and dielectric filling materials on the current-voltage characteristics of the device. Carrier accumulation on frontiers defined by the trenches causes a modulation of the hole density inside the conduction channel as the bias voltage varies and this gives rise to a diode-like characteristic. For a 1.2 {mu}m-long channel, plots of the electric field distribution show that a nonlinear transport regime is reached at a moderate reverse and forward bias of {+-} 2 V. Plots of the carrier velocity along the conduction channel show that holes remain hot for a few hundreds of nm outside the nanometre-wide channel, at a bias of {+-} 10 V. Filling the etched trenches with a high-{kappa} dielectric material gives rise to a lower threshold voltage, V{sub th}. A similar decrease of V{sub th} is also achieved by reducing the longitudinal and/or the transverse trench width. Our simulation results provide useful design guidelines for future integrated self-switching-diode-based circuits.

  1. Effects of Thermal and Solvent Aging on Breakdown Voltage of TPE, PBT/PET Alloy, and PBT Insulated Low Voltage Electric Wire

    Eun-Soo Park


    Full Text Available Tests were performed to evaluate the effects of thermal and solvent aging on the mechanical and dielectric breakdown properties of four types of polyester resins, namely, the insulation layer of poly(butylene terephthalat (PBT- based thermoplastic elastomer (TPE, TPE1, poly(butylene 2,6-naphthalate-based TPE (TPE2, PBT/poly(ethylene terephthalate alloy (Alloy, and PBT extruded onto a copper conductor of low voltage electric wire. The tensile specimens used in this series were prepared from the same extruded resins. The prepared electric wires and tensile specimens were thermally aged in air and in toluene, xylene, TCB, and NMP. When Alloy and PBT were thermally aged in toluene, xylene and TCB at 120°C for 6 h, the tensile properties were significantly decreased compared to TPE1 and TPE2 at the same condition. The reduction of elongation at break of Alloy was more discernible than that of PBT. This result indicated that Alloy is more affected by thermal and solvent ageing. Among them, TPE2 showed the highest breakdown voltage (BDV, and it has also the highest BDV after thermal and solvent aging.

  2. Insulating process for HT-7U central solenoid model coils


    The HT-7U superconducting Tokamak is a whole superconducting magnetically confined fusion device. The insulating system of its central solenoid coils is critical to its properties. In this paper the forming of the insulating system and the vacuum-pressure-impregnating (VPI) are introduced, and the whole insulating process is verified under the superconducting experiment condition.

  3. Thermal insulator

    Yamamoto, R.; Asada, Y.; Matsuo, Y.; Mikoda, M.


    A thermal insulator comprises an expanded resin body having embedded therein an evacuated powder insulation portion which consists of fine powder and a container of film-like plastics or a film-like composite of plastics and metal for enclosing the powder. The resin body has been expanded by a Freon gas as a blowing agent. Since a Freon gas has a larger molecular diameter than the constituent gases of air, it is less likely to permeate through the container than air. Thus present invention provides a novel composite insulator which fully utilizes the benefits of vacuum insulation without necessitating a strong and costly material for a vacuum container.

  4. Cellulose Insulation


    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.

  5. Electric detection of the spin-Seebeck effect in magnetic insulator in the presence of interface barrier

    Uchida, K; Ota, T; Kajiwara, Y; Saitoh, E [Institute for Materials Research, Tohoku University, Sendai 980-8577 (Japan); Umezawa, H; Kawai, H, E-mail: [FDK Corporation, Shizuoka 431-0495 (Japan)


    The spin-Seebeck effect (SSE), the spin-voltage generation as a result of a temperature gradient, has recently been observed in ferrimagnetic insulator LaY{sub 2}Fe{sub 5}O{sub 12} films by means of the inverse spin-Hall effect in Pt films. Here we investigate the SSE using LaY{sub 2}Fe{sub 5}O{sub 12}/SiO{sub 2}(Cu)/Pt systems, where the LaY{sub 2}Fe{sub 5}O{sub 12} and Pt layers are separated by SiO{sub 2} (Cu) thin-film barriers. The experimental results show that the SSE signal disappears in the LaY{sub 2}Fe{sub 5}O{sub 12}/SiO{sub 2}/Pt system, but the finite signal appears in the LaY{sub 2}Fe{sub 5}O{sub 12}/Cu/Pt system, indicating that the direct contacts between the LaY{sub 2}Fe{sub 5}O{sub 12} and normal metals is necessary for generating the SSE signal.

  6. Label-free electrical determination of trypsin activity by a silicon-on-insulator based thin film resistor.

    Neff, Petra A; Serr, Andreas; Wunderlich, Bernhard K; Bausch, Andreas R


    A silicon-on-insulator (SOI) based thin film resistor is employed for the label-free determination of enzymatic activity. We demonstrate that enzymes, which cleave biological polyelectrolyte substrates, can be detected by the sensor. As an application, we consider the serine endopeptidase trypsin, which cleaves poly-L-lysine (PLL). We show that PLL adsorbs quasi-irreversibly to the sensor and is digested by trypsin directly at the sensor surface. The created PLL fragments are released into the bulk solution due to kinetic reasons. This results in a measurable change of the surface potential allowing for the determination of trypsin concentrations down to 50 ng mL(-1). Chymotrypsin is a similar endopeptidase with a different specificity, which cleaves PLL with a lower efficiency as compared to trypsin. The activity of trypsin is analyzed quantitatively employing a kinetic model for enzyme-catalyzed surface reactions. Moreover, we have demonstrated the specific inactivation of trypsin by a serine protease inhibitor, which covalently binds to the active site of the enzyme.

  7. Fusion Machinery

    Sørensen, Jakob Balslev; Milosevic, Ira


    the vesicular SNARE VAMP2/synaptobrevin-2 and the target (plasma membrane) SNAREs SNAP25 and syntaxin-1 results in fusion and release of neurotransmitter, synchronized to the electrical activity of the cell by calcium influx and binding to synaptotagmin. Formation of the SNARE complex is tightly regulated...... and appears to start with syntaxin-1 bound to an SM (Sec1/Munc18-like) protein. Proteins of the Munc13-family are responsible for opening up syntaxin and allowing sequential binding of SNAP-25 and VAMP2/synaptobrevin-2. N- to C-terminal “zippering” of the SNARE domains leads to membrane fusion...

  8. Anomalous Rashba spin-orbit interaction in electrically controlled topological insulator based on InN/GaN quantum wells.

    Lepkowski, S P; Bardyszewski, Witold


    We study theoretically the topological phase transition and the Rashba spin-orbit interaction in electrically biased InN/GaN quantum wells. We show that that for properly chosen widths of quantum wells and barriers, one can effectively tune the system through the topological phase transition applying an external electric field perpendicular to the QW plane. We find that in InN/GaN quantum wells with the inverted band structure, when the conduction band s-type level is below the heavy hole and light hole p-type levels, the spin splitting of the subbands decreases with increasing the amplitude of the electric field in the quantum wells, which reveals the anomalous Rashba effect. Derived effective Rashba Hamiltonians can describe the subband spin splitting only for very small wave vectors due to strong coupling between the subbands. Furthermore, we demonstrate that for InN/GaN quantum wells in a Hall bar geometry, the critical voltage for the topological phase transition depends distinctly on the width of the structure and a significant spin splitting of the edge states lying in the two-dimensional band gap can be almost switched off by increasing the electric field in quantum wells only by a few percent. We show that the dependence of the spin splitting of the upper branch of the edge state dispersion curve on the wave vector has a threshold-like behavior with the on/off spin splitting ratio reaching two orders of magnitude for narrow Hall bars. The threshold wave vector depends weakly on the Hall bar width, whereas it increases significantly with the bias voltage due to an increase of the energetic distance between the s-type and p-type quantum well energy levels and a reduction of the coupling between the subbands.

  9. Power and Thermal Technology for Air and Space. Delivery Order 0006: Nano-filled Polymers for Electrical Insulation


    T. Kvarts, “Increasing the Electrical Discharge Endurance of Acid Anhydride Cured DGEBA Epoxy Resin by Dispersion of Nanoparticle Silica,” High...56 pbw Jeffamine D-400. This resin systems gels at room temperature over the course of several hours. A thermal post cure cycle is used to complete...the cure . A B Figure 1: Chemical structures of the resin system components used in this study: A) EPON 828 (n=0.3), and B

  10. Electrical insulation properties of RF-sputtered LiPON layers towards electrochemical stability of lithium batteries

    Vieira, E. M. F.; Ribeiro, J. F.; Silva, M. M.; Barradas, N. P.; Alves, E.; Alves, A.; Correia, M. R.; Goncalves, L. M.


    Electrochemical stability, moderate ionic conductivity and low electronic conductivity make the lithium phosphorous oxynitride (LiPON) electrolyte suitable for micro and nanoscale lithium batteries. The electrical and electrochemical properties of thin-film electrolytes can seriously compromise full battery performance. Here, radio-frequency (RF)-sputtered LiPON thin films were fabricated in nitrogen plasma under different working pressure conditions. With a slight decrease in the deposition pressure from 6 to 1  ×  10-3 mbar, the 600 nm thick LiPON film reveals an electric resistivity increase from 108 to 1010 Ω · cm, respectively. UV- micro-Raman spectroscopy confirms the nitrogen incorporation on the Li3PO4 material, while scanning electron microscopy, Rutherford backscattering spectrometry and nuclear reaction analysis show a well-defined compact structure with a composition of Li2.2PO2.2N0.6 for the higher electrical-resistivity film. An ionic conductivity close to 3  ×  10-7 S cm-1 at room temperature (22 °C) was measured by AC impedance spectroscopy. Thermal properties were investigated through the differential scanning calorimetry technique. LiPON films reveal high optical transmission (>75%) in the UV-vis range, which could be interesting for transparent electronic devices.

  11. Estimation of winding insulation resistance to the corona discharges

    Leonov, A.; Red'ko, V.; Soldatenko, E.


    This article presents test results of enameled winding wires, characterizing an insulation electrical and mechanical strength. Standard and original test methods were used. Note that existing standard test methods do not estimate enamel insulation resistance to the electrical loads under winding operation of variable-speed drive. We show that estimation of wire corona resistance can be done by high frequency electrical impulse testing. Wire insulation plays the main role of reliability of insulation system.

  12. MHD pressure drop in ferritic pipes of fusion blankets

    Reimann, J.; Buehler, Leo E-mail:; Messadek, K.; Stieglitz, R


    Magnetohydrodynamic flows in pipes of ferromagnetic material is an important issue for liquid metal blanket concepts using MANET as wall material. Fusion relevant magnetic fields of 4-8 T cause high pressure drop in the blanket header where a massive structure of ferromagnetic material exists. It is briefly outlined that in the blanket the reduction of pressure drop due to magnetic shielding is limited to about 10%. Remarkable reduction of pressure drop is possible by means of electrical insulation that prevents currents from short-circuiting through the very thick walls of the headers. Direct contact of the insulating material with the liquid metal is excluded by using metallic liners. Results are reported on the fabrication of such a test section and corresponding pressure drop measurements confirm the effective contribution of the electrical decoupling.

  13. Insulation systems for superconducting transmission cables

    Tønnesen, Ole


    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...

  14. Auto-magnetizing liners for magnetized inertial fusion

    Slutz, S. A.; Jennings, C. A.; Awe, T. J.; Shipley, G. A.; Hutsel, B. T.; Lamppa, D. C.


    The MagLIF (Magnetized Liner Inertial Fusion) concept [Slutz et al., Phys. Plasmas 17, 056303 (2010)] has demonstrated fusion-relevant plasma conditions [Gomez et al., Phys. Rev. Lett. 113, 155003 (2014)] on the Z accelerator using external field coils to magnetize the fuel before compression. We present a novel concept (AutoMag), which uses a composite liner with helical conduction paths separated by insulating material to provide fuel magnetization from the early part of the drive current, which by design rises slowly enough to avoid electrical breakdown of the insulators. Once the magnetization field is established, the drive current rises more quickly, which causes the insulators to break down allowing the drive current to follow an axial path and implode the liner in the conventional z-pinch manner. There are two important advantages to AutoMag over external field coils for the operation of MagLIF. Low inductance magnetically insulated power feeds can be used to increase the drive current, and AutoMag does not interfere with diagnostic access. Also, AutoMag enables a pathway to energy applications for MagLIF, since expensive field coils will not be damaged each shot. Finally, it should be possible to generate Field Reversed Configurations (FRC) by using both external field coils and AutoMag in opposite polarities. This would provide a means to studying FRC liner implosions on the 100 ns time scale.

  15. Development of intermetallic coatings for fusion power applications

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


    In the design of liquid-metal cooling systems, corrosion resistance of structural materials and magnetohydrodynamic (MHD) force and its subsequent influence on thermal hydraulics and corrosion are major concerns. 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 walls. Vanadium and V-base alloys are potential materials for structural applications in a fusion reactor. Insulator coatings inside the tubing are required when the system is cooled by liquid metals. Various intermetallic films were produced on V, V-t, and V-20 Ti, V-5Cr-t and V-15Cr-t, and Ti, and Types 304 and 316 stainless steel. The intermetallic layers were developed by exposure of the materials to liquid lithium of 3--5 at.% and containing dissolved metallic solutes at temperatures of 416--880{degrees}C. Subsequently, electrical insulator coatings were produced by reaction of the reactive layers with dissolved nitrogen in liquid lithium or by air oxidation under controlled conditions at 600--1000{degrees}C. These reactions converted the intermetallic layers to electrically insulating oxide/nitride or oxy-nitride layers. This coating method could be applied to a commercial product. 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 because the coating is formed by liquid-phase reaction. This paper will discuss initial results on the nature of the coatings and their in-situ electrical resistivity characteristics in liquid lithium at high temperatures.

  16. Development of TiO2 electrical insulation coating on Ag-alloy sheathed Bi2Sr2CaCu2O8-x round-wire

    Kandel, H.; Lu, J.; Jiang, J.; Chen, P.; Matras, M.; Craig, N.; Trociewitz, U. P.; Hellstrom, E. E.; Larbalestier, D. C.


    We have developed TiO2 coating on Ag-alloy sheathed Bi2Sr2CaCu2O8-x (Bi-2212) round-wire conductor for electrical insulation in Bi-2212 magnets. The green coating has a base layer comprised of TiO2, polyvinyl butyral (PVB) and a small amount of polysilicate and a top layer made of polyacrylic. The coating was applied on the conductor using a continuous reel-to-reel dip coating process and showed very good adherence and flexibility that is suitable for magnet coil winding. The thickness of the coating is a function of slurry viscosity, wire withdrawal speed and wire radius. Small test coils were built with the coated Bi-2212 round-wires and were heat treated at 100 atm pressure. During the heat treatment, the PVB and polyacrylic were removed from the green coating and the polysilicate decomposed to SiO2 that served as a sintering aid for TiO2. After the heat treatment, the coating remained strongly adhered to the conductor and did not have a detrimental effect on the critical current (Ic) values. The breakdown voltage was about 150 V across a 7 μm thick heat treated coating on Bi-22112 round-wire conductor, corresponding to a dc dielectric strength of about 21 MV m-1.

  17. Electrical Characterization of Metal-Insulator-Metal Capacitors with Atomic-Layer-Deposited HfO2 Dielectrics for Radio Frequency Integrated Circuit Application

    HUANG Yu-Jian; HUANG Yue; DING Shi-Jin; ZHANG Wei; LIU Ran


    Metal-insulator-metal (MIM) capacitors with atomic-layer-deposited HfO2 dielectric and TaN electrodes are investigated for rf integrated circuit applications. For 12nm HfO2, the fabricated capacitor exhibits a high capacitance density of 15.5fF/μm2 at 100kHz, a small leakage current density of 6.4 × 10-9 A/cm2 at 1.8 V and 125℃, a breakdown electric field of 2.6 MV/cm as well as voltage coefficients of capacitance (VCCs) of 2110ppm/V2 and -824 ppm/V at 100kHz. Further, it is deduced that the conduction mechanism in the high field range is dominated by the Poole-Frenkel emission, and the conduction mechanism in the low field range is possibly related to trap-assisted tunnelling. Finally, comparison of various HfO2 MIM capacitors is present,suggesting that the present MIM capacitor is a promising candidate for future rf integrated circuit application.

  18. Electrical Characterization of TiO2 Insulator Based Pd / TiO2 / Si MIS Structure Deposited by Sol-Gel Process

    Kumar Shubham


    Full Text Available Electrical characterization of a Pd / TiO2 / Si MIS structure has been reported in this paper. The TiO2 layer has been deposited on n-Si substrate by spin coating sol-gel process using Titanium Tetraisopropoxide [Ti(OC3H74]. The current-voltage and capacitance-voltage characteristics were studied at room temperature (300 K by applying the dc bias gate voltage swept from – 3 to 3 V for the frequency range of 50 kHz to 1 MHz. The study reveals that the capacitance in the accumulation region has frequency dispersion in high frequencies (> 10 kHz which is attributed to leakage behavior of TiO2 insulating layer, interface states and oxide defects. Different models of current conduction mechanism have been applied to study the measured data. It is found that Schottky-Richardson (SR emission model is applicable at low bias voltage, Frenkel-Poole (FP emission model at moderate bias voltages while Fowler-Nordheim (FN tunneling dominates at higher bias voltages. TiO2 based MIS devices having high dielectric constant and good interface quality with Si substrate are expected to play a major role in microelectronic applications.

  19. Sensoring Fusion Data from the Optic and Acoustic Emissions of Electric Arcs in the GMAW-S Process for Welding Quality Assessment

    Eber Huanca Cayo


    Full Text Available The present study shows the relationship between welding quality and optical-acoustic emissions from electric arcs, during welding runs, in the GMAW-S process. Bead on plate welding tests was carried out with pre-set parameters chosen from manufacturing standards. During the welding runs interferences were induced on the welding path using paint, grease or gas faults. In each welding run arc voltage, welding current, infrared and acoustic emission values were acquired and parameters such as arc power, acoustic peaks rate and infrared radiation rate computed. Data fusion algorithms were developed by assessing known welding quality parameters from arc emissions. These algorithms have showed better responses when they are based on more than just one sensor. Finally, it was concluded that there is a close relation between arc emissions and quality in welding and it can be measured from arc emissions sensing and data fusion algorithms.

  20. Sensoring fusion data from the optic and acoustic emissions of electric arcs in the GMAW-S process for welding quality assessment.

    Alfaro, Sadek Crisóstomo Absi; Cayo, Eber Huanca


    The present study shows the relationship between welding quality and optical-acoustic emissions from electric arcs, during welding runs, in the GMAW-S process. Bead on plate welding tests was carried out with pre-set parameters chosen from manufacturing standards. During the welding runs interferences were induced on the welding path using paint, grease or gas faults. In each welding run arc voltage, welding current, infrared and acoustic emission values were acquired and parameters such as arc power, acoustic peaks rate and infrared radiation rate computed. Data fusion algorithms were developed by assessing known welding quality parameters from arc emissions. These algorithms have showed better responses when they are based on more than just one sensor. Finally, it was concluded that there is a close relation between arc emissions and quality in welding and it can be measured from arc emissions sensing and data fusion algorithms.

  1. Development of a Remote Insulation Test Device for High-Voltage Electrical Motors%一种远程高压电机绝缘测试装置的开发研究

    何锁侠; 佟洪明; 肖骥; 李开寒


    介绍了一种远程高压电机绝缘测试装置。根据系统需求,独自研发了一种加入了RS-485通信模块和控制模块的新一代电子式电阻表。基于西门子S7-200型PLC对高压电机绝缘监测设备、高压继电器、机械抓进行控制。建立了触摸屏、PLC、绝缘检测仪之间的通讯,实现了高压电机绝缘的远程测量功能。通过运用本装置,提高了高压电机绝缘检测的自动化水平,降低了设备维修频率,并保障了工人的人身安全。%A remote insulation test device for high -voltage electrical motors is introduced. To meet system requirement, a new -generation electronic insulation tester incorporating RS -485 communication module and control module was independently developed. Based on Siemens S7-200 PLC the system can control high-voltage motor insulation monitoring devices, high voltage relays and mechanical grips. Communication between the touch screen, PLC and insulation tester was established, realizing remote insulation measurement for high voltage motors. The device improves the automation level of high-voltage motor insulation test, reduces the frequency of equipment maintenance and ensures personal safety.

  2. Electromagnetic Nondestructive Evaluation of Wire Insulation and Models of Insulation Material Properties

    Bowler, Nicola; Kessler, Michael R.; Li, Li; Hondred, Peter R.; Chen, Tianming


    Polymers have been widely used as wiring electrical insulation materials in space/air-craft. The dielectric properties of insulation polymers can change over time, however, due to various aging processes such as exposure to heat, humidity and mechanical stress. Therefore, the study of polymers used in electrical insulation of wiring is important to the aerospace industry due to potential loss of life and aircraft in the event of an electrical fire caused by breakdown of wiring insulation. Part of this research is focused on studying the mechanisms of various environmental aging process of the polymers used in electrical wiring insulation and the ways in which their dielectric properties change as the material is subject to the aging processes. The other part of the project is to determine the feasibility of a new capacitive nondestructive testing method to indicate degradation in the wiring insulation, by measuring its permittivity.

  3. Development of insulating coatings for liquid metal blankets

    Malang, S.; Borgstedt, H.U. [Kernforschungszentrum Karlsruhe GmbH (Germany); Farnum, E.H. [Los Alamos National Lab., NM (United States); Natesan, K. [Argonne National Lab., IL (United States); Vitkovski, I.V. [Efremov Inst., St. Petersburg (Russian Federation). MHD-Machines Lab.


    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.

  4. Effect of annealing temperature on the electrical properties of Au/Ta{sub 2}O{sub 5}/n-GaN metal-insulator-semiconductor (MIS) structure

    Prasanna Lakshmi, B.; Rajagopal Reddy, V.; Janardhanam, V. [Sri Venkateswara University, Department of Physics, Tirupati (India); Siva Pratap Reddy, M.; Lee, Jung-Hee [Kyungpook National University, School of Electrical Engineering and Computer Science, Daegu (Korea, Republic of)


    We report on the effect of an annealing temperature on the electrical properties of Au/Ta{sub 2}O{sub 5}/n-GaN metal-insulator-semiconductor (MIS) structure by current-voltage (I-V) and capacitance-voltage (C-V) measurements. The measured Schottky barrier height ({Phi} {sub bo}) and ideality factor n values of the as-deposited Au/Ta{sub 2}O{sub 5}/n-GaN MIS structure are 0.93 eV (I-V) and 1.19. The barrier height (BH) increases to 1.03 eV and ideality factor decreases to 1.13 upon annealing at 500 {sup circle} C for 1 min under nitrogen ambient. When the contact is annealed at 600 {sup circle} C, the barrier height decreases and the ideality factor increases to 0.99 eV and 1.15. The barrier heights obtained from the C-V measurements are higher than those obtained from I-V measurements, and this indicates the existence of spatial inhomogeneity at the interface. Cheung's functions are also used to calculate the barrier height ({Phi} {sub bo}), ideality factor (n), and series resistance (R{sub s}) of the Au/Ta{sub 2}O{sub 5}/n-GaN MIS structure. Investigations reveal that the Schottky emission is the dominant mechanism and the Poole-Frenkel emission occurs only in the high voltage region. The energy distribution of interface states is determined from the forward bias I-V characteristics by taking into account the bias dependence of the effective barrier height. It is observed that the density value of interface states for the annealed samples with interfacial layer is lower than that of the density value of interface states of the as-deposited sample. (orig.)

  5. Effect of the Electric Field on the Contamination Accumulation Characteristic of the Insulators%电场对复合绝缘子积污特性影响的探究

    王晶; 陈林华; 刘宇; 梁曦东


    绝缘子的积污规律很大程度上取决于绝缘子周围尘粒的运动特性,通过试验和数值计算两种途径探究了各种因素对尘粒运动的影响.通过同轴电极模型试验探究了电场对尘粒运动的影响,建立了简化的二维轴对称数值计算模型,模拟了尘粒在极化力、电场力、稳态曳力和重力同时作用下的运动轨迹,仿真结果与试验结果比较符合,最后,计算了真实特高压直流复合绝缘子周围的电场和电位分布.研究结果表明:极化力非常小,对尘粒运动不会产生影响,但可使尘粒在绝缘子表面粘附地更加牢固;电场力可使荷电尘粒在电场线的方向上发生明显偏转,而绝缘子伞裙之间的电场方向基本与伞裙表面垂直,因此,电场力可促进荷电尘粒在直流绝缘子表面的沉积;在风速较大时,稳态曳力对尘粒运动起主导作用,尘粒随风而动.从电场对尘粒运动所产生的影响出发能更好地解释不同类型的绝缘子在不同运行条件下的积污规律.%Contamination accumulation characteristic of the insulators depends on the kinetic characteristic of the par ticles moving around the insulators to a great degree. We researched the effect of different factors on the dust parti cles ' motion by means of experiments and numerical calculation. The effect of electric field was researched by coaxi al electrode model experiments. A simplified 2D axial symmetric calculation model was built to simulate the dust particles' trajectories under the composite effect of the polarization force, the electric field force, the steady-state drag force and the gravitational force. The simulation resulted in good coincidence with the experimental phenome non. In the end, the distribution of the electric field and the electric potential around an actual EHVDC insulator was calculated. The results are as bellow; The polarization force is very weak and can not influence the dust parti cles' motion but

  6. Wool insulation

    O`Shea, Angus


    Wool insulation usually comes in two forms, as loose fill or batts. The reliability of loose fill as an insulator, the thickness of batts and the wool`s vulnerability to insect and moth attack are considered to be problems. The purpose of this research was to create a commercial wool insulation product to overcome these limitations, at the same time withstanding the Australian and international standards for fire resistance. The project also considered the market potential of such a product with a view to commercialization. The loft or thickness problem was resolved by covering the wool with an oven baked adhesive. A fire retardant and anti-insect treatment was incorporated into the spray process to produce a viable product.

  7. Radiation Insulation


    The Apollo and subsequent spacecraft have had highly effective radiation barriers; made of aluminized polymer film, they bar or let in heat to maintain consistent temperatures inside. Tech 2000, formerly Quantum International Corporation used the NASA technology in its insulating materials, Super "Q" Radiant Barrier, for home, industry and mobile applications. The insulation combines industrial aluminum foil overlaid around a core of another material, usually propylene or mylar. The outer layer reflects up to 97 percent of heat; the central layer creates a thermal break in the structure and thus allows low radiant energy emission. The Quantum Cool Wall, used in cars and trucks, takes up little space while providing superior insulation, thus reducing spoilage and costs. The panels can also dampen sound and engine, exhaust and solar heat.

  8. Topological insulators

    Franz, Marcel


    Topological Insulators, volume six in the Contemporary Concepts of Condensed Matter Series, describes the recent revolution in condensed matter physics that occurred in our understanding of crystalline solids. The book chronicles the work done worldwide that led to these discoveries and provides the reader with a comprehensive overview of the field. Starting in 2004, theorists began to explore the effect of topology on the physics of band insulators, a field previously considered well understood. However, the inclusion of topology brings key new elements into this old field. Whereas it was

  9. Design of Measurement System for Electrical Tree in XLPE Cable Insulation at High Temperature%高温下交联聚乙烯电缆绝缘中树枝测试系统设计

    陈向荣; 徐阳; 王猛; 杨文虎; 刘英; 曹晓珑; 刘景光


    An experimental system of electrical treeing in XLPE cable insulation at high temperature was designed. The electrical tree growth and partial discharge characteristics at different temperature in high voltage XLPE cable insulation were studied under 13 Kv power frequency voltages. The results indicate that the effect of temperature on the tree growth is dominant. The whole system can be used to the real-time observation of electrical tree growth and continuous partial discharge measurement at high temperature, which provides an experimental platform for studying the initiation and propagation mechanism of electrical tree in XLPE cable insulation as well as its partial discharge characteristics at high temperature.%设计了高温下交联聚乙烯(XLPE)电缆绝缘中电树枝化的实验系统,在外施工频电压有效值为13 kV下,对不同温度下高压XLPE电缆绝缘中电树枝生长及其局部放电特性进行研究,结果表明,温度对电树枝的生长具有重要影响,整个系统可以用于高温下电树枝生长过程的实时观测与局部放电连续测量,为研究高温下XLPE电缆绝缘中电树枝引发与生长机理及其局部放电特性分析提供了实验研究平台.

  10. Effect of moisture on the electrical performance of transition-joints for medium voltage paper-insulated cables; Elektrische Beeintraechtigung durch Feuchtigkeit an oelgetraenkten Isolierpapieren. Mittelspannungsuebergangsmuffen

    Cardinaels, Jos [Nexans Network Solution, Erembodegem (Belgium). Produktentwicklung; Baesch, Manfred [Nexans Power Accessories Germany, Dortmund (Germany). Produkt- und Qualitaetsmanagement


    Paper-insulated cables are constructed with an impervious metallic outer jacket in order to protect them against ingress of moisture. On 'modern' transition-joints to XLPE-insulated cables, this metal barrier is interrupted, hence, a risk of moisture penetration exists. This text presents measurements of water-vapour permeability of used materials and discusses the results of ageing tests. (orig.)

  11. Preliminary Study on Insulating Design of Electrical Device in Helium for High Temperature Gas-Cooled Reactor%高温气冷堆氦气环境中电气设备绝缘设计研究

    于晓丽; 杨小勇; 周世新; 王捷


    应用巴申定律研究了氦气的电气击穿特性,并与空气的绝缘特性进行比较.以高温气冷堆氦气透平发电系统电机腔室的设计参数为例,结合氦气的巴申曲线,对氦气条件下气体压力和极间距离的关系进行深入探讨,并提出氦气环境中电气设备绝缘设计需关注的问题.研究结果表明,氦气最小击穿电压为150~200 V,绝缘特性较差,电气设备绝缘结构设计应考虑氦气环境压力的影响,现有针对压水堆电站电气设备绝缘结构的验收准则和试验方法并不完全适用于氦气环境.%The breakdown performance of helium was studied by Paschen law, comparing with air. Combined with the operation parameter of generator in gas turbine coupled with high temperature gas-cooled reactor and the Paschen curve of helium, the relationship between pressure and insulating structure was discussed. The key points for the insulation design of the electrical device in helium were presented. The results show that the insulation performance for helium which lowest breakdown potentials is 150-200 V is much worse than that of air. The existing test and inspect guidelines of the insulation structure for the pressure water reactor can't be used for the helium. High permeability for helium may be an important reason to destroy the insulation structure.

  12. Translucent Insulation

    Rahbek, Jens Eg


    Two new types of translucent materials are presented. One is translucent fiber insulation and the other type is a new type of hony-comb made of Celulose-acetat. Data for the materials and calculations of energy savings when using the materials in building envelopes are presented....

  13. The Insulation Properties of Oil-Impregnated Insulation Paper Reinforced with Nano-TiO2

    Ruijin Liao; Cheng Lv; Lijun Yang; Yiyi Zhang; Weiqiang Wu; Chao Tang


    Oil-impregnated insulation paper has been widely used in transformers because of its low cost and desirable physical and electrical properties. However, research to improve the insulation properties of oil-impregnated insulation paper is rarely found. In this paper, nano-TiO2 was used to stick to the surface of cellulose which was used to make insulation paper. After oil-impregnated insulation paper reinforced by nano-TiO2 was prepared, the tensile strength, breakdown strength, and dielectric...

  14. On Effective Holographic Mott Insulators

    Baggioli, Matteo


    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 amount of disorder in a specific way. These models imply a c...

  15. Improved insulator layer for MIS devices

    Miller, W. E.


    Insulating layer of supersonic conductor such as LaF sub 3 has been shown able to impart improved electrical properties to photoconductive detectors and promises to improve other metal/insulator/semiconductor (MIS) devices, e.g., MOSFET and integrated circuits.

  16. Topological insulators: A romance with many dimensions

    Manoharan, Hari C.


    Electric charges on the boundaries of certain insulators are programmed by topology to keep moving forward when they encounter an obstacle, rather than scattering backwards and increasing the resistance of the system. This is just one reason why topological insulators are one of the hottest topics in physics right now.

  17. Electric Insulation Intelligent Detection System IPC Terminal Design%客车电气绝缘智能检测系统工控机端设计

    丁振凡; 王小明; 吴小元; 邓建明; 周斌


    In order to ensure the safety and reliability of the vehicle electrical wiring, a routine work in the railway department is to detect the quality of the various components on the vehicle and find the problem timely. The insulation resistance of a component is an important factor to reflect the quality. In the industrial control terminal, Java was used to implement the application. The detection process is controlled by communication between IPC and SCM. SCM drives the detection pen to detect by send signals. Detection results will be displayed on IPC. The IPC can determine the lower limit of resistance for the detect object and can alarm when receiving abnormal data. Detection results were stored in database. Truth and effectiveness of data can be guaranteed through operational processes of three detections and one verification. Detection report about each vehicle was drawn using iText. Testing range is 1M Ω~10000MΩ. Experimental results show that, the measurement accuracy to ± 2% measurements, measuring the stability of sampling time control in 3~4S, stable data.%为确保车辆电气配线安全可靠,铁路部门的一项常规性工作是对客车上各部件的质量进行检测,及时找出故障点,而部件绝缘电阻是体现材料质量的一项重要因素;工控机端系统用Java技术编程实现;通过工控机与单片机之间的通信控制检测过程,由单片机发送信号驱动检测笔进行检测,检测结果送工控机界面显示,能根据检测对象智能确定其下限电阻,对异常数据及时报警;检测数据记录在数据库中,通过3检1验的操作流程保证检验数据的真实有效性;利用iText组件绘制每个车对应的检测报表;测试量程范围为1MΩ~10000MΩ;实测结果表明,测量精度达到±2%测量值,测量稳定采样时间控制在3~4 s间,数据稳定.


    Naraeva R.R


    Full Text Available The present paper is devoted to the research of the method for determining the parameters and plot of insulation damage in the networks of 6 to 35 kV with isolated neutral on the basis of measuring the operating parameters of the network. In the considered three-phase circuit with a symmetric source of EMF and symmetric loading there was a damage of insulation in one of the phases. The calculations are carried out for the transmission line equivalent circuit with a branch line by means of node-potential method. An investigation of the influence of the magnitude of insulation conductivity in the place of damage of different sections of the network upon the accuracy of determining the insulation conductivity is conducted using the data from digital models. The research of this method is performed by advancing hypotheses about the place of damage and by considering the influence of the multiplicity of increasing insulation conductivity of the damaged section and accuracy class of measuring devices.

  19. 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

    Damberger, S.; Guenther, M.; Kluender, M.; Moeller, K.P.; Wenk, N.


    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)

  20. 46 CFR 111.60-21 - Cable insulation tests.


    ...-GENERAL REQUIREMENTS Wiring Materials and Methods § 111.60-21 Cable insulation tests. All cable for electric power and lighting and associated equipment must be checked for proper insulation resistance to... 46 Shipping 4 2010-10-01 2010-10-01 false Cable insulation tests. 111.60-21 Section...

  1. Development of indigenous insulation material for superconducting magnets and study of its characteristics under influence of intense neutron irradiation

    Sharma, Rajiv; Tanna, V. L.; Rao, C. V. S.; Abhangi, Mitul; Vala, Sudhirsinh; Sundaravel; Varatharajan, S.; Sivakumar, S.; Sasi, K.; Pradhan, S.


    Epoxy based glass fiber reinforced composites are the main insulation system for the superconducting magnets of fusion machines. 14MeV neutrons are generated during the DT fusion process, however the energy spectra and flux gets modified to a great extent when they reach the superconducting magnets. Mechanical properties of the GFRP insulation material is reported to degrade up to 30%. As a part of R & D activity, a joint collaboration with IGCAR, Kalpakkam has been established. The indigenous insulation material is subjected to fast neutron fluence of 1014 - 1019 n/m2 (E>0.1 MeV) in FBTR and KAMINI Reactor, India. TRIM software has been used to simulate similar kind of damage produced by neutrons by ion irradiation with 5 MeV Al ions and 3 MeV protons. Fluence of the ions was adjusted to get the same dpa. We present the test experiment of neutron irradiation of the composite material (E-glass, S-glass fiber boron free and DGEBA epoxy). The test results of tensile, inter laminar shear and electrical breakdown strength as per ASTM standards, assessment of micro-structure surface degradation before and after irradiation will be presented. MCNP simulations are carried out for neutron flux, dose and damages produced in the insulation material.

  2. High-performance insulator structures for accelerator applications

    Sampayan, S.E.; Caporaso, G.J.; Sanders, D.M.; Stoddard, R.D.; Trimble, D.O. [Lawrence Livermore National Lab., CA (United States); Elizondo, J.; Krogh, M.L.; Wieskamp, T.F. [Allied Signal, Inc., Kansas City, MO (United States). Federal Mfg. and Technologies


    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.

  3. Insulating coupling for drill collars and method of manufacture thereof

    Stone, F.A.; Maron, R.J.


    This patent describes an insulating drill collar joint, including: a first metallic drill collar segment having a first threaded section with a coating of electrically insulating ceramic material; insulating coating in the range of from 0.002 to 0.006 inch thick; and a second metallic drill collar segment connected to first drill collar segment; second drill collar segment having a second threaded section engaged with the insulation coated section of the first drill collar section. An electrically insulated drill collar joint is formed.

  4. PD-pulse characteristics in rotating machine insulation

    Holbøll, Joachim; Henriksen, Mogens; Jensen, A;


    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...

  5. Common test methods for insulating and sheathing materials of electrical cables - Part 4 Methods specific to polyethylene and polypropylene compounds. Section Two

    International Electrotechnical Commission. Geneva


    Gives the methods for measurement of elongation at break after pre-conditioning, for wrapping test after pre-conditioning, for wraping test after thermal ageing in air, for measurement of mass increase, for long-term stability test and for measurement of copper-catalysed oxidative degradation, which apply to polyolefin insulations.

  6. Improved DC Gun Insulator

    M.L. Neubauer, K.B. Beard, R. Sah, C. Hernandez-Garcia, G. Neil


    Many user facilities such as synchrotron 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 have poor reliability, in part because energetic electrons bury themselves in the ceramic, creating a buildup of charge and causing eventual puncture. A novel ceramic manufacturing process is proposed. It will incorporate bulk resistivity in the region where it is needed to bleed off accumulated charge caused by highly energetic electrons. This process will be optimized to provide an appropriate gradient in bulk resistivity from the vacuum side to the air side of the HV standoff ceramic cylinder. A computer model will be used to determine the optimum cylinder dimensions and required resistivity gradient for an example RF gun application. A ceramic material example with resistivity gradient appropriate for use as a DC gun insulator will be fabricated by glazing using doping compounds and tested.

  7. Unconventional Fermi surface in an insulating state

    Harrison, Neil [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Tan, B. S. [Cambridge Univ., Cambridge (United Kingdom); Hsu, Y. -T. [Cambridge Univ., Cambridge (United Kingdom); Zeng, B. [National High Magnetic Field Lab., Tallahassee, FL (United States); Hatnean, M. Ciomaga [Univ. of Warwick, Coventry (United Kingdom); Zhu, Z. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Hartstein, M. [Cambridge Univ., Cambridge (United Kingdom); Kiourlappou, M. [Cambridge Univ., Cambridge (United Kingdom); Srivastava, A. [Cambridge Univ., Cambridge (United Kingdom); Johannes, M. D. [Center for Computational Materials Science, Washington, DC (United States); Murphy, T. P. [National High Magnetic Field Lab., Tallahassee, FL (United States); Park, J. -H. [National High Magnetic Field Lab., Tallahassee, FL (United States); Balicas, L. [National High Magnetic Field Lab., Tallahassee, FL (United States); Lonzarich, G. G. [Cambridge Univ., Cambridge (United Kingdom); Balakrishnan, G. [Univ. of Warwick, Coventry (United Kingdom); Sebastian, Suchitra E. [Cambridge Univ., Cambridge (United Kingdom)


    Insulators occur in more than one guise; a recent finding was a class of topological insulators, which host a conducting surface juxtaposed with an insulating bulk. Here, we report the observation of an unusual insulating state with an electrically insulating bulk that simultaneously yields bulk quantum oscillations with characteristics of an unconventional Fermi liquid. We present quantum oscillation measurements of magnetic torque in high-purity single crystals of the Kondo insulator SmB6, which reveal quantum oscillation frequencies characteristic of a large three-dimensional conduction electron Fermi surface similar to the metallic rare earth hexaborides such as PrB6 and LaB6. As a result, the quantum oscillation amplitude strongly increases at low temperatures, appearing strikingly at variance with conventional metallic behavior.

  8. Mitigation of Electrothermal Instabilities with Thick Insulating Coatings

    Peterson, Kyle; Awe, Thomas; Yu, Edmund; Sinars, Daniel; Cuneo, Michael


    We will show results of recent experiments on Sandia's Z facility that demonstrate a dramatic reduction in instability growth when thick insulating coatings are used to mitigate electrothermal instability growth in magnetically driven imploding liners. These results also provide further evidence that the inherent surface roughness as a result of target fabrication is not the dominant seed for the growth of Magneto-Rayleigh-Taylor (MRT) instabilities in liners with carefully machined smooth surfaces (~100 nm surface RMS or better), but rather electrothermal instabilities that form early in the electrical current pulse as Joule heating melts and vaporizes the liner surface. More importantly, these results suggest a mechanism for possibly reducing the integral MRT instability growth substantially in magnetically driven inertial confinement fusion concepts such as MagLIF. Sandia is a multiprogram laboratory operated by Sandia Corporation, a Lockheed Martin Company, for the United States Department of Energy's National Nuclear Security Administration under contract DE-AC04-94AL85000.

  9. Selection of the external insulation distance for electric equipment as function of the environmental pollution level; Seleccion de la distancia de aislamiento externo de equipo electrico en funcion del nivel de contaminacion ambiental

    Villa Velazquez Santillanes, Francisco [Gerencia de Proyectos Geotermoelectricos de la Comision Federal de Electricidad, Morelia (Mexico)


    Geographic, environmental and meteorological conditions, are considered as decisive factors in the basic engineering and design of electric substations. These conditions are considered through the use of environmental and meteorological parameters, such as: pollution type, creepage distance, pollution level, maximum wind rate, maximum temperature, seismic coefficient and maximum pluvial precipitation. In some cases, the pollution level determines the external insulation distance. The pollution level factor is quantified as the equivalent salt accumulation in milligrams per square centimeter of the insulation surface (DESD), occurring during certain time, that produces an electric effect similar to that of the real pollutant. [Espanol] Los aspectos geograficos, ambientales y meteorologicos son factores que se deben considerar en la ingenieria basica de las subestaciones electricas. En el diseno de estas se utilizan parametros asociados con las condiciones ambientales y meteorologicas, como son: tipo de contaminacion, distancia de fuga, nivel de contaminacion, velocidad maxima del viento, temperatura ambiental maxima, temperatura ambiental minima, coeficiente sismico y maxima precipitacion pluvial. La contaminacion se produce por la depositacion de polvo y otras sustencias quimicas sobre los aisladores. Para cuantificar la contaminacion se recurre al concepto de Densidad Equivalente de Sal Depositada (DESD), que consiste en medir la contaminacion en funcion de la cantidad de sal (NaC1) depositada en cierto tiempo, por centimetro cuadrado del aislador, tal que su comportamiento electrico es equivalente al de los contaminantes reales.

  10. Magnetic-confinement fusion

    Ongena, J.; Koch, R.; Wolf, R.; Zohm, H.


    Our modern society requires environmentally friendly solutions for energy production. Energy can be released not only from the fission of heavy nuclei but also from the fusion of light nuclei. Nuclear fusion is an important option for a clean and safe solution for our long-term energy needs. The extremely high temperatures required for the fusion reaction are routinely realized in several magnetic-fusion machines. Since the early 1990s, up to 16 MW of fusion power has been released in pulses of a few seconds, corresponding to a power multiplication close to break-even. Our understanding of the very complex behaviour of a magnetized plasma at temperatures between 150 and 200 million °C surrounded by cold walls has also advanced substantially. This steady progress has resulted in the construction of ITER, a fusion device with a planned fusion power output of 500 MW in pulses of 400 s. ITER should provide answers to remaining important questions on the integration of physics and technology, through a full-size demonstration of a tenfold power multiplication, and on nuclear safety aspects. Here we review the basic physics underlying magnetic fusion: past achievements, present efforts and the prospects for future production of electrical energy. We also discuss questions related to the safety, waste management and decommissioning of a future fusion power plant.

  11. Influence of Ti substitution on the electrical properties of metal-ferroelectric (BiFeO3)-insulator (HfO2)-silicon structures for nonvolatile memory applications

    Pi-Chun Juan, Trevor; Liu, Yu-Wei


    Metal-ferroelectric (Ti-substituted BiFeO3)-insulator (HfO2)-semiconductor structures have been fabricated via the cosputtering technique. Ti4+ substitution at the Fe site was investigated through x-ray photoelectron spectra and x-ray diffraction patterns at postannealing temperatures of 500 to 700 °C. The capacitance-voltage memory windows as functions of the insulator film thickness and the dc power for Ti were measured and compared. A memory window of 3.1 V was obtained at a sweep voltage of 8 V under O2-rich conditions. The leakage current and the charge injection effect, especially gate injection, can be greatly improved by Ti substitution. The effects of the postannealing temperature and the substitution amount on the leakage current can be well explained by the defect reaction model.

  12. Study on electrical insulation property of the insulating sealing gaskets for warship piping system%舰船管系绝缘密封垫片电绝缘性能研究

    李竹影; 曹文康; 刘冶; 张晓东


    The asbestos rubber fiber gaskets and epoxy gaskets were soaked in the seawater, alkaline solution( 10%NaOH ),acid solution(10%H2SO4)and heavy oil,and the variation of the volume resistivity and surface resistivity of the gaskets with soaking time were studied. The results showed that the wet resistivity of the asbestos rubber fiber gaskets reduced to 102Ω( orΩ·cm)level when being soaked in the alkaline solution and acid solution for two months and the period of validity of the insulation was inferred to four months in seawater,and however, the wet resistivity of the epoxy gaskets could remain 104~6Ω(orΩ·cm)level,and as the conclu-sion,the performance of the insulation of the epoxy gaskets is much better than that of asbestos rubber fiber gaskets.%研究了用于舰船管系异种金属绝缘的石棉橡胶纤维垫片和环氧垫片在海水、碱溶液(10%NaOH溶液)、酸溶液(10%H2SO4溶液)和重油中浸泡后,其体电阻率和面电阻率随浸泡时间的变化规律.实验结果显示,石棉橡胶纤维垫片在酸、碱溶液中浸泡两个月后,其湿态电阻降低到102欧姆(或欧姆?厘米)量级,在海水中的电绝缘有效期约为4个月,环氧垫片的湿态电阻可保持为104~6欧姆(或欧姆?厘米)量级,环氧材料组成的垫片其绝缘性能远好于石棉橡胶纤维垫片的绝缘性能.

  13. Electric Power Transmission Lines

    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...

  14. Calculation on The Surface Electric Field Distribution of Suspension-type Insulators Covered with Nonuniform Surface Pollution%覆有不均匀污层线路悬式绝缘子表面电场分布计算

    项阳; 郭洁; 雒铮


    研究污秽潮湿状态下绝缘子表面电场特征对提高绝缘子可靠性有重要的意义。基于污秽潮湿状态绝缘子周围电场的电阻性特点,采用离散电阻模型研究了轴向不均匀的污层对绝缘子电场和电位分布的影响。计算结果表明:绝缘子表面电场强度切向分量与绝缘子表面污秽轴向分布不均匀程度有关;流过污层的泄漏电流的焦耳热效应会加剧绝缘子表面电导率的不均匀程度。%It is meaningful for the improvement of insulator reliability to research the surface electric field characteristics in a condition of dirt and moisture.Based on the resistance characterisc of the insulator field in the condition,this paper adopts the discrete resistor model to study the influence of nonuniform pollution layer along the insulator’s axis on the distributions of insulator’s electric field and potential.The results show that the tangential component of the insulator’s surface electric field intensty depends on the nonuniform,and the nonuniform of insulator’s surface conductivity becomes worse by Joule heat effect of the leakage current through pollution layer.

  15. Peaceful Uses of Fusion

    Teller, E.


    Applications of thermonuclear energy for peaceful and constructive purposes are surveyed. Developments and problems in the release and control of fusion energy are reviewed. It is pointed out that the future of thermonuclear power reactors will depend upon the construction of a machine that produces more electric energy than it consumes. The fuel for thermonuclear reactors is cheap and practically inexhaustible. Thermonuclear reactors produce less dangerous radioactive materials than fission reactors and, when once brought under control, are not as likely to be subject to dangerous excursions. The interaction of the hot plasma with magnetic fields opens the way for the direct production of electricity. It is possible that explosive fusion energy released underground may be harnessed for the production of electricity before the same feat is accomplished in controlled fusion processes. Applications of underground detonations of fission devices in mining and for the enhancement of oil flow in large low-specific-yield formations are also suggested.

  16. Review of Research on Space Charge in XLPE Insulation under AC Electric Field%交流电场下XLPE绝缘空间电荷研究综述

    陈广辉; 王安妮; 李云强; 王伟


    XLPE电缆目前广泛地应用于电力系统中,如何评估和预测现场运行电缆的老化及早期劣化的程度,是电缆绝缘状态评估的重要内容,然而这项研究在国内仍是空白.XLPE电缆的制造工艺过程、运行中的过电压和温升以及耐压试验过程都可能造成XLPE电缆绝缘特性的改变,导致绝缘性能下降,形成陷阱,特别是空间电荷的形成,畸变原有电场分布,直接影响XLPE电缆的绝缘特性.大量研究表明,在直流电场下空间电荷危害XLPE电缆绝缘,关于交流电压下空间电荷对XLPE电缆绝缘影响的探索较少.综述了交流电场下空间电荷效应对XLPE电缆绝缘影响的相关研究成果,并介绍了测量固体介质空间电荷分布的电声脉冲法,为从空间电荷测量角度研究XLPE电缆绝缘老化程度和状态评估提供了参考.%As XLPE cables are widely used in power system, the evaluation and prediction for the aging and the early insulation degradation of XLPE cables under certain operating conditions are an important parts in the evaluation of the cable insulation; however, very little research has been conducted in China. The imperfect manufacturing process, overvoltage and temperature rises in the operation, and withstand voltage tests may affect the cable insulation, reduce the insulation capabilities, and result in traps which can capture charge carriers and form space charges, distort the origin electrical field and exert direct impact on the insulation properties. While many studies show that under DC voltage the space charge causes damages to the insulation, little research on the space charge's impacts on XLPE insulation under AC voltage is known. The pulsed electro-acoustic system for measuring space charge distribution in solid dielectric is introduced and relevant studies on space charge's effect on XLPE cables under ac stress are reviewed in this paper. The results of these studies can be used as reference in the study

  17. Structural and electrical properties of metal ferroelectric insulator semiconductor structure of Al/SrBi2Ta2O9/HfO2/Si using HfO2 as buffer layer

    Roy, A.; Dhar, A.; Bhattacharya, D.; Ray, S. K.


    Ferroelectric SrBi2Ta2O9 (SBT) thin films have been deposited by the radio-frequency magnetron sputtering technique on bare p-Si as well as on HfO2 insulating buffer p-Si. XRD patterns revealed the formation of a well-crystallized SBT perovskite thin film on the HfO2 buffer layer. The electrical properties of the metal-ferroelectric-insulator-semiconductor (MFIS) structure were characterized by varying thicknesses of the HfO2 layer. The MFIS structure exhibits a maximum clockwise C-V memory window of 1.60 V when the thickness of the HfO2 layer was 12 nm with a lower leakage current density of 6.20 × 10-7 A cm-2 at a positive applied voltage of 7 V. However, the memory window reaches a maximum value of 0.7 V at a bias voltage of ±5 and then decreases due to charge injection in the case of the insulating buffer layer thickness of 3 nm. The density of oxide trapped charges at/near the buffer layer-ferroelectric interface is studied by the voltage stress method. Capacitance-voltage (C-V) and leakage current density (J-V) characteristics of the Al/SBT/HfO2/Si(1 0 0) capacitor indicate that the introduction of the HfO2 buffer layer prevents interfacial diffusion between the SBT thin film and the Si substrate effectively and improves the interface quality. Furthermore, the Al/SBT/HfO2/Si structures exhibit excellent retention characteristics, the high and low capacitance values clearly distinguishable for over 1 h and 30 min. This shows that the proposed Al/SrBi2Ta2O9/HfO2/Si structure is ideally suitable for high performance ferroelectric memories.

  18. Electrical engineering. High and very high voltage substations. Metal envelope insulated substations; Genie electrique. Postes a haute et tres haute tensions. Poste sous enveloppe metallique (PSEM)

    Taillebois, J.P. [Centre National d' Expertise Reseaux du Gestionnaire du Reseau de Transport d' Electricite (France)


    Metal envelope substations with pressurized sulfur hexafluoride (SF{sub 6}) allow to considerably reduce the insulation distances between the different components of high and very-high voltage substations (phases, ground, switches and circuit breakers), thus leading to compact power systems with reduced dimensions. This article presents the technical characteristics of metal envelope substations: design parameters and dimensioning, specific constraints, safety, technological solutions, characteristic values, diagnosis and monitoring methods, use of metal envelope substations in power distribution systems, perspectives of evolution. (J.S.)

  19. Room-temperature electrically pumped near-infrared random lasing from high-quality m-plane ZnO-based metal-insulator-semiconductor devices


    Epitaxial m-plane ZnO thin films have been deposited on m-plane sapphire substrates at a low temperature of 200°C by atomic layer deposition. A 90° in-plane rotation is observed between the m-plane ZnO thin films and the sapphire substrates. Moreover, the residual strain along the ZnO [−12-10] direction is released. To fabricate metal-insulator-semiconductor devices, a 50-nm Al2O3 thin film is deposited on the m-plane ZnO thin films. It is interesting to observe the near-infrared random lasin...

  20. Theoretical-Experimental Analysis of the Effects of Grain Boundaries on the Electrical Properties of SOI (Silicon-on-Insulator) MOSFETS.


    Insulating Substrate", IEEE Electron Device Lett., vol. EDL-l, pp. 206-208, Oct. 1980. 2. B.-Y. Tsaur, M. W. Geis, J. C. C. Fan, D. J. Silversmith , and P...Electron Device Lett., vol. EDL-I, pp. 206-208, Oct. 1980. 3. B.-Y. Tsaur, M. W. Geis, J. C. C. Fan, D. J. Silversmith , and P. W. Mountain, "n-Channel Deep...Lett., vol. EDL-I, pp. 206-208, Oct. 1980. 2. B.-Y. Tsaur, M. W. Geis, J. C. C. Fan, D. J. Silversmith , and R. W. Mountain, "n-Channel Deep-Depletion

  1. On effective holographic Mott insulators

    Baggioli, Matteo; Pujolàs, Oriol


    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.

  2. Physical and electrical properties of induced high-k ZrHfO crystallization with ZrN cap by high power impulse magnetron sputtering for metal-gate metal-insulator-semiconductor structures

    Tsai, Jung-Ruey; Juan, Pi-Chun; Lin, Cheng-Li; Lin, Guo-Cheng


    Metal-gate TiN/ZrN/ZrHfO/p-Si metal-insulator-semiconductor (MIS) structures have been fabricated in this work. The physical and electrical properties were characterized. The crystallization of high-k ZrHfO thin-film is induced by high power impulse magnetron sputtering (HIPIMS) during the deposition of ZrN capping layer. The binding energies and depth profiles were investigated by X-ray photoelectron spectroscopy (XPS). It is found that Zr and Hf out-diffusion from high-k dielectric in samples with HIPIMS is lesser than those in samples with the conventional DC magnetron sputtering (DCMS). The dielectric constant which strongly relates to the tetragonal phase becomes higher and the flatband voltage shift shows smaller by using the HIPIMS method than by the conventional DCMS. The cation and anion vacancies have been investigated by the defect reaction model.

  3. The Insulation Properties of Oil-Impregnated Insulation Paper Reinforced with Nano-TiO2

    Ruijin Liao


    Full Text Available Oil-impregnated insulation paper has been widely used in transformers because of its low cost and desirable physical and electrical properties. However, research to improve the insulation properties of oil-impregnated insulation paper is rarely found. In this paper, nano-TiO2 was used to stick to the surface of cellulose which was used to make insulation paper. After oil-impregnated insulation paper reinforced by nano-TiO2 was prepared, the tensile strength, breakdown strength, and dielectric properties of the oil-impregnated insulation paper were investigated to determine whether the modified paper had a better insulation performance. The results show that there were no major changes in tensile strength, and the value of the breakdown strength was greatly improved from 51.13 kV/mm to 61.78 kV/mm. Also, the values of the relative dielectric constant, the dielectric loss, and conductivity declined. The discussion reveals that nano-TiO2 plays a major role in the phenomenon. Because of the existence of nano-TiO2, the contact interface of cellulose and oil was changed, and a large number of shallow traps were produced. These shallow traps changed the insulation properties of oil-impregnated insulation paper. The results show that the proposed solution offers a new method to improve the properties of oil-impregnated insulation paper.

  4. Electrical and magnetic properties of n-Cd sub 1 sub - sub x Mn sub x Te close to the metal-insulator transition

    Read, D E


    temperatures and in zero field an activated form of the conductivity is observed. In applied magnetic fields (B > 50 mT) Efros-ShkIovskii variable range hopping is observed in the insulating phase. These results are attributed to the formation of a hard gap in the density of states, having a magnetic origin. At higher fields an insulator-metal phase transition occurs. In the metallic phase the conductivity can be described by a quantum correction to the zero temperature conductivity due to the effect of electron-electron interactions. Results obtained before and after illumination are consistent with scaling theory of electron localisation, having a critical exponent close to unity, indicative of the importance of electron-electron interactions. A reduction in the value of the critical field is seen after increasing the carrier density (B sub c = 2.0 and 1.3 T for n = 3.3 and 3.8 x 10 sup 1 sup 7 cm sup - sup 3 respectively). At low temperatures an anisotropy in the resistivity has been measured for samples i...

  5. Extraction of Zinc from Electric Arc Furnace Dust by Alkaline Leaching Followed by Fusion of the Leaching Residue with Caustic Soda

    赵由才; R.Stanforth


    Extractability of zinc from two types of electric arc furnace (EAF) dusts containing 24.8% and 16.8% of zinc respectively (denoted as Sample A and Sample B) were tested using direct alkaline leaching followed by fusion of the resulting leaching residues with caustic soda. The experimental results show that the extraction of zinc is heavily dependent on the contents of iron in the dusts. The higher iron content, the lower extraction of zinc is obtained. 53% and 38% of zinc can be extracted when both dusts were directly contacted with 5mol·L-1 NaOH solution for 42h. The remaining zinc left in the leaching residues, which supposed to be present as zinc ferrites, can be further leached when the residues were fused with caustic soda. Quantitative extraction of zinc can be obtained from the leaching residue of Sample A while only 85% from Sample B. The extractability of zinc from dusts wit hvarious contents of iron is compared. The production flowsheet for zinc from the dusts using the process proposed is discussed.

  6. A review of magnetic insulation

    Zósimo Arévalo Velosa


    Full Text Available High energy devices are designed to work with extremely high electric and magnetic fields. As a consequence, these devices show non-linear phenomena and behaviour, such as magnetic insulation which alters electron trajectory. A mathematical analysis and review of magnetic insulation were carried out as a consequence of non-linearity to find frontier conditions and solutions to the problem. This paper was aimed at presenting the topic in a way which is easier for that part of the academic community which is unfamiliar with it to understand it. The paper gives a description of the phenomena developed by high electric and magnetic fields in a vacuum plane diode, some equations modelling the phenomenon, proves its existence and finds positive solutions based on upper and lower solutions for boundary limit problems and gives some practical applications.

  7. Vacuum Insulator Development for the Dielectric Wall Accelerator

    Harris, J R; Blackfield, D; Caporaso, G J; Chen, Y; Hawkins, S; Kendig, M; Poole, B; Sanders, D M; Krogh, M; Managan, J E


    At Lawrence Livermore National Laboratory, we are developing a new type of accelerator, known as a Dielectric Wall Accelerator, in which compact pulse forming lines directly apply an accelerating field to the beam through an insulating vacuum boundary. The electrical strength of this insulator may define the maximum gradient achievable in these machines. To increase the system gradient, we are using 'High Gradient Insulators' composed of alternating layers of dielectric and metal for the vacuum insulator. In this paper, we present our recent results from experiment and simulation, including the first test of a High Gradient Insulator in a functioning Dielectric Wall Accelerator cell.

  8. The quest for fusion power

    Cowley, Steven C.


    Fusion power is one of a very few sustainable options to replace fossil fuels as the world's primary energy source. Although the conditions for fusion have been reached, much remains to be done to turn scientific success into commercial electrical power.

  9. 5th Duisburg thermal insulation days. Fuenfte Duisburger Waermedaemm-Tage

    Agst, J. (ed.)


    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).

  10. Fusion plasma physics

    Stacey, Weston M


    This revised and enlarged second edition of the popular textbook and reference contains comprehensive treatments of both the established foundations of magnetic fusion plasma physics and of the newly developing areas of active research. It concludes with a look ahead to fusion power reactors of the future. The well-established topics of fusion plasma physics -- basic plasma phenomena, Coulomb scattering, drifts of charged particles in magnetic and electric fields, plasma confinement by magnetic fields, kinetic and fluid collective plasma theories, plasma equilibria and flux surface geometry, plasma waves and instabilities, classical and neoclassical transport, plasma-materials interactions, radiation, etc. -- are fully developed from first principles through to the computational models employed in modern plasma physics. The new and emerging topics of fusion plasma physics research -- fluctuation-driven plasma transport and gyrokinetic/gyrofluid computational methodology, the physics of the divertor, neutral ...

  11. Deduction of Steady-State Cable Quench Limits for Various Electrical Insulation Schemes with Application to LHC and HL-LHC Magnets

    Granieri, P


    Undesired quenches of superconducting magnets can be a limiting factor for the operation of the LHC accelerator, both for its forthcoming exploitation at full energy as well as for its future upgrades. An accurate knowledge of the quench limit, the maximum amount of heat deposit the magnets can withstand, is required to be able to prevent beam induced quenches. In this paper we provide an overview of the heat extraction through the multitude of cable insulation schemes used in particle accelerators in the past 20 years and foreseen for the coming years. Based on the relevant heat transfer measurements, we deduce steady-state cable quench limits both for the LHC Nb-Ti magnets and for the future HL-LHC Nb3Sn ones. We provide them for different operating conditions and different locations within the coil.

  12. Electrical Bistabilities and Conduction Mechanisms of Nonvolatile Memories Based on a Polymethylsilsesquioxane Insulating Layer Containing CdSe/ZnS Quantum Dots

    Ma, Zehao; Ooi, Poh Choon; Li, Fushan; Yun, Dong Yeol; Kim, Tae Whan


    Nonvolatile memory (NVM) devices based on a metal-insulator-metal structure consisting of CdSe/ZnS quantum dots embedded in polymethylsilsesquioxane dielectric layers were fabricated. The current-voltage ( I- V) curves showed a bistable current behavior and the presence of hysteresis. The current-time ( I- t) curves showed that the fabricated NVM memory devices were stable up to 1 × 104 s with a distinct ON/OFF ratio of 104 and were reprogrammable when the endurance test was performed. The extrapolation of the I- t curve to 105 s with corresponding current ON/OFF ratio 1 × 105 indicated a long performance stability of the NVM devices. Schottky emission, Poole-Frenkel emission, trapped-charge limited-current and Child-Langmuir law were proposed as the dominant conduction mechanisms for the fabricated NVM devices based on the obtained I- V characteristics.

  13. Temperature dependent electrical characterisation of Pt/HfO{sub 2}/n-GaN metal-insulator-semiconductor (MIS) Schottky diodes

    Shetty, Arjun, E-mail:; Vinoy, K. J. [Electrical Communication Engineering, Indian Institute of Science, Bangalore, India 560012 (India); Roul, Basanta; Mukundan, Shruti; Mohan, Lokesh; Chandan, Greeshma; Krupanidhi, S. B. [Materials Research Centre, Indian Institute of Science, Bangalore, India 560012 (India)


    This paper reports an improvement in Pt/n-GaN metal-semiconductor (MS) Schottky diode characteristics by the introduction of a layer of HfO{sub 2} (5 nm) between the metal and semiconductor interface. The resulting Pt/HfO{sub 2}/n-GaN metal-insulator-semiconductor (MIS) Schottky diode showed an increase in rectification ratio from 35.9 to 98.9(@ 2V), increase in barrier height (0.52 eV to 0.63eV) and a reduction in ideality factor (2.1 to 1.3) as compared to the MS Schottky. Epitaxial n-type GaN films of thickness 300nm were grown using plasma assisted molecular beam epitaxy (PAMBE). The crystalline and optical qualities of the films were confirmed using high resolution X-ray diffraction and photoluminescence measurements. Metal-semiconductor (Pt/n-GaN) and metal-insulator-semiconductor (Pt/HfO{sub 2}/n-GaN) Schottky diodes were fabricated. To gain further understanding of the Pt/HfO{sub 2}/GaN interface, I-V characterisation was carried out on the MIS Schottky diode over a temperature range of 150 K to 370 K. The barrier height was found to increase (0.3 eV to 0.79 eV) and the ideality factor decreased (3.6 to 1.2) with increase in temperature from 150 K to 370 K. This temperature dependence was attributed to the inhomogeneous nature of the contact and the explanation was validated by fitting the experimental data into a Gaussian distribution of barrier heights.

  14. Osteoclast Fusion

    Marie Julie Møller, Anaïs; Delaissé, Jean-Marie; Søe, Kent


    suggesting that fusion partners may specifically select each other and that heterogeneity between the partners seems to play a role. Therefore, we set out to directly test the hypothesis that fusion factors have a heterogenic involvement at different stages of nuclearity. Therefore, we have analyzed...... on the nuclearity of fusion partners. While CD47 promotes cell fusions involving mono-nucleated pre-osteoclasts, syncytin-1 promotes fusion of two multi-nucleated osteoclasts, but also reduces the number of fusions between mono-nucleated pre-osteoclasts. Furthermore, CD47 seems to mediate fusion mostly through......Investigations addressing the molecular keys of osteoclast fusion are primarily based on end-point analyses. No matter if investigations are performed in vivo or in vitro the impact of a given factor is predominantly analyzed by counting the number of multi-nucleated cells, the number of nuclei per...

  15. Membrane fusion

    Bendix, Pól Martin


    At Stanford University, Boxer lab, I worked on membrane fusion of small unilamellar lipid vesicles to flat membranes tethered to glass surfaces. This geometry closely resembles biological systems in which liposomes fuse to plasma membranes. The fusion mechanism was studied using DNA zippering...... between complementary strands linked to the two apposing membranes closely mimicking the zippering mechanism of SNARE fusion complexes....

  16. Insulator Surface Flashover Due to UV Illumination

    Javedani, J B; Houck, T L; Lahowe, D A; Vogtlin, G E; Goerz, D A


    The surface of an insulator under vacuum and under electrical charge will flashover when illuminated by a critical dose of ultra-violet (UV) radiation - depending on the insulator size and material, insulator cone angle, the applied voltage and insulator shot-history. A testbed comprised of an excimer laser (KrF, 248 nm, {approx}16 MW, 30 ns FWHM,), a vacuum chamber, and a negative polarity dc high voltage power supply ({le} -60 kV) were assembled to test 1.0 cm thick angled insulators for surface-flashover. Several candidate insulator materials, e.g. High Density Polyethylene (HDPE), Rexolite{reg_sign} 1400, Macor{trademark} and Mycalex, of varying cone angles were tested against UV illumination. Commercial energy meters were used to measure the UV fluence of the pulsed laser beam. In-house designed and fabricated capacitive probes (D-dots, >12 GHz bandwidth) were embedded in the anode electrode underneath the insulator to determine the time of UV arrival and time of flashover. Of the tested insulators, the +45 degree Rexolite insulator showed more resistance to UV for surface flashover; at UV fluence level of less than 13 mJ/cm{sup 2}, it was not possible to induce a flashover for up to -60 kV of DC potential across the insulator's surface. The probes also permitted the electrical charge on the insulator before and after flashover to be inferred. Photon to electron conversion efficiency for the surface of Rexolite insulator was determined from charge-balance equation. In order to understand the physical mechanism leading to flashover, we further experimented with the +45 degree Rexolite insulator by masking portions of the UV beam to illuminate only a section of the insulator surface; (1) the half nearest the cathode and subsequently, (2) the half nearest the anode. The critical UV fluence and time to flashover were measured and the results in each case were then compared with the base case of full-beam illumination. It was discovered that the time for the

  17. Construction and operation of parallel electric and magnetic field spectrometers for mass/energy resolved multi-ion charge exchange diagnostics on the Tokamak Fusion Test Reactor

    Medley, S. S.; Roquemore, A. L.


    A novel charge exchange spectrometer using a dee-shaped region of parallel electric and magnetic fields was developed at the Princeton Plasma Physics Laboratory for neutral particle diagnostics on the Tokamak Fusion Test Reactor (TFTR). The E∥B spectrometer has an energy range of 0.5⩽A (amu)E (keV)⩽600 and provides mass-resolved energy spectra of H+, D+, and T+ (or 3He+) ion species simultaneously during a single discharge. The detector plane exhibits parallel rows of analyzed ions, each row containing the energy dispersed ions of a given mass-to-charge ratio. The detector consists of a large area microchannel plate (MCP) which is provided with three rectangular, semicontinuous active area strips, one coinciding with each of the mass rows for detection of H+, D+, and T+ (or 3He+) and each mass row has 75 energy channels. To suppress spurious signals attending operation of the plate in the magnetic fringe field of the spectrometer, the MCP was housed in a double-walled iron shield with a wire mesh ion entrance window. Using an accelerator neutron generator, the MCP neutron detection efficiency was measured to be 1.7×10-3 and 6.4×10-3 counts/neutron/cm2 for 2.5 MeV-DD and 14 MeV-DT neutrons, respectively. The design and calibration of the spectrometer are described in detail, including the effect of MCP exposure to tritium, and results obtained during high performance D-D operation on TFTR are presented to illustrate the performance of the E∥B spectrometer. The spectrometers were not used during D-T plasma operation due to the cost of providing the required radiation shielding.

  18. Spin Hall effect induced spin transfer through an insulator

    Chen, Wei; Sigrist, Manfred; Manske, Dirk


    When charge current passes through a normal metal that exhibits the spin Hall effect, spin accumulates at the edge of the sample in the transverse direction. We predict that this spin accumulation, or spin voltage, enables quantum tunneling of spin through an insulator or vacuum to reach a ferromagnet without transferring charge. In a normal metal/insulator/ferromagnetic insulator trilayer (such as Pt/oxide/YIG), the quantum tunneling explains the spin-transfer torque and spin pumping that exponentially decay with the thickness of the insulator. In a normal metal/insulator/ferromagnetic metal trilayer (such as Pt/oxide/Co), the spin transfer in general does not decay monotonically with the thickness of the insulator. Combining with the spin Hall magnetoresistance, this tunneling mechanism points to the possibility of a tunneling spectroscopy that can probe the magnon density of states of a ferromagnetic insulator in an all-electrical and noninvasive manner.

  19. Fractal analysis of the electrical discharges' surface paths in polymeric insulation considering different pollution levels; Analisis fractal de las trayectorias de descargas electricas superficiales en aislamiento polimerico considerando diferentes niveles de contaminacion

    Palacios Lopez, Arturo


    In this thesis tree patterns of superficial breakdown in polymeric insulator of Silicon Rubber are generated. Experimental arrangement rod-rod was used on the basis of norm ASTM D 2303-85. Pollution levels on the basis of norm IEC 507 were also used. The experimental values of Fractal Dimension for each case of pollution were reported. A self similar method called Box Counting for the fractal dimension calculus and for the self affine methods an R/S and Variogram were used. According to the results, it was concluded that the tree patterns of superficial electric breakdown in Silicon Rubber is self similar and its value does not depend on the degree of pollution, that is equivalent to the concentration of salt for liter of water or to the Equivalent Salt Deposition (ESDD), in the surface of an insulator. [Spanish] En el presente trabajo se inducen descargas electricas superficiales en un aislamiento polimerico de Hule Silicon, el arreglo experimental que se utilice es punta-punta con base en la norma ASTM D 2303-85 y los niveles de contaminacion con base en la norma IEC 507. Se reportan los valores experimentales de la Dimension Fractal para cada caso de contaminacion, se utilice el metodo auto similar de conteo de cuadros, para el calculo de la Dimension Fractal y para metodos auto afines se utilice analisis R/S y variograma. Con los resultados obtenidos se concluye que la trayectoria de la descarga electrica superficial en un polimero de Hule Silicon es auto similar y su valor no depende del grado de contaminacion, el cual es equivalente a la concentracion de gramos de sal por litro de agua o a la densidad de sal depositada (DESD), en la superficie de un aislador.

  20. Dielectric insulation and high-voltage issues

    Tommasini, D


    Electrical faults are in most cases dramatic events for magnets, due to the large stored energy which is potentially available to be dissipated at the fault location. After a reminder of the principles of electrostatics in Section 1, the basic mechanisms of conduction and breakdown in dielectrics are summarized in Section 2. Section 3 introduces the types and function of the electrical insulation in magnets, and Section 4 its relevant failure mechanisms. Section 5 deals with ageing and, finally, Section 6 gives some principles for testing. Though the School specifically dealt with warm magnets, for completeness some principles of dielectric insulation for superconducting accelerator magnets are briefly summarized in a dedicated appendix.

  1. Fusion rings and fusion ideals

    Andersen, Troels Bak

    by the so-called fusion ideals. The fusion rings of Wess-Zumino-Witten models have been widely studied and are well understood in terms of precise combinatorial descriptions and explicit generating sets of the fusion ideals. They also appear in another, more general, setting via tilting modules for quantum...

  2. Fusion neutronics

    Wu, Yican


    This book provides a systematic and comprehensive introduction to fusion neutronics, covering all key topics from the fundamental theories and methodologies, as well as a wide range of fusion system designs and experiments. It is the first-ever book focusing on the subject of fusion neutronics research. Compared with other nuclear devices such as fission reactors and accelerators, fusion systems are normally characterized by their complex geometry and nuclear physics, which entail new challenges for neutronics such as complicated modeling, deep penetration, low simulation efficiency, multi-physics coupling, etc. The book focuses on the neutronics characteristics of fusion systems and introduces a series of theories and methodologies that were developed to address the challenges of fusion neutronics, and which have since been widely applied all over the world. Further, it introduces readers to neutronics design’s unique principles and procedures, experimental methodologies and technologies for fusion systems...

  3. Electrical Conduction Mechanisms in Metal-Insulator-Metal (MIM) Structure with TiO x N y Thin Films Deposited with Different O/N Ratios

    Libardi, Juliano; Grigorov, Korneli G.; Moraes, Rodrigo S.; Guerino, Marciel; Da Silva Sobrinho, Argemiro S.; Massi, Marcos


    In this work, the current-voltage characteristics of titanium oxynitride thin films were measured and the charge carrier transport mechanisms established as a function of film composition. The films were deposited by magnetron sputtering, where the oxygen/nitrogen ratio was varied via a pulsing technique to enable the achievement of desired concentrations. Thus, the obtained films showed metallic titanium nitrate (TiN) or semiconductor titanium dioxide (TiO2) character and were used to fabricate metal-insulator-metal structures. An ohmic conduction mechanism was identified in the films with higher nitrogen incorporation or presenting TiN-rich phase. Decrease in the nitrogen content resulted in films with TiO2-rich phase. In this case, Poole-Frenkel and space-charge-limited current conduction mechanisms were observed. The dielectric constants were calculated from the high-frequency capacitance-voltage dependences, with a reduction from 10 to 3 being observed due to the stoichiometric changes and probable incorporation of defects into the film structure. Finally, the film composition and structural characteristics of the films were revealed by Rutherford backscattering and x-ray diffraction techniques, respectively.

  4. Electrical engineer's reference book

    Laughton, M A


    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

  5. Insulated Fiber Brush.

    An insulated-strand fiber brush is provided for a DC motor /generator. The brush is comprised of a plurality of fiber segments which are insulated from one another near the contact surface of a rotor bar. In one embodiment, insulating spacers are fixed to a brush assembly and wear with the fibers, and in another embodiment insulation is provided by a separate shell. (Author)

  6. 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

    Hu, Longhua


    Materials, such as electrical wire, used in spacecraft must pass stringent fire safety standards. Tests for such standards are typically performed under normal gravity conditions and then extended to applications under microgravity conditions. 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 (downward) speeds (0−25 cm/s) at several inclination angles (0−75°) under normal gravity conditions. The differences from those previously obtained under microgravity conditions were quantified and correlated to provide a reference for the development of fire safety test standards for electrical wires to be used in space exploration. It was found that as the opposed-flow speed increased for a specified inclination angle (except the horizontal case), LOC first increased, then decreased and finally increased again. The first local maximum of this LOC variation corresponded to a critical forced flow speed resulted from the change in flame spread pattern from concurrent to counter-current type. This critical forced flow speed correlated well with the buoyancy-induced flow speed component in the wire\\'s direction when the flame base width along the wire was used as a characteristic length scale. LOC was generally higher under the normal gravity than under the microgravity and the difference between the two decreased as the opposed-flow speed increases, following a reasonably linear trend at relatively higher flow speeds (over 10 cm/s). The decrease in the difference in LOC under normal- and microgravity conditions as the opposed-flow speed increases correlated well with the gravity acceleration component in the wire\\'s direction, providing a measure to extend LOC determined by the tests under normal gravity conditions (at various inclination angles and opposed

  7. Gas insulated transmission line having low inductance intercalated sheath

    Cookson, Alan H.


    A gas insulated transmission line including an outer sheath, an inner conductor disposed within the outer sheath, and an insulating gas between the inner conductor and the outer sheath. The outer sheath comprises an insulating tube having first and second ends, and having interior and exterior surfaces. A first electrically conducting foil is secured to the interior surface of the insulating tube, is spirally wound from one tube end to the second tube end, and has a plurality of overlapping turns. A second electrically conducting foil is secured to the exterior surface of the insulating tube, and is spirally wound in the opposite direction from the first electrically conducting foil. By winding the foils in opposite directions, the inductances within the intercalated sheath will cancel each other out.

  8. Experimental Realizations of Magnetic Topological Insulator and Topological Crystalline Insulator

    Xu, Suyang


    Over the past few years the experimental research on three-dimensional topological insulators have emerged as one of the most rapidly developing fields in condensed matter physics. In this talk, we report on two new developments in the field: The first part is on the dynamic interplay between ferromagnetism and the Z2 topological insulator state (leading to a magnetic topological insulator). We present our spin-resolved photoemission and magnetic dichroic experiments on MBE grown films where a hedgehog-like spin texture is revealed on the magnetically ordered surface of Mn-Bi2Se3 revealing a Berry's phase gradient in energy-momentum space of the crystal. A chemically/electrically tunable Berry's phase switch is further demonstrated via the tuning of the spin groundstate in Mn-Bi2Se3 revealed in our data (Nature Physics 8, 616 (2012)). The second part of this talk describes our experimental observation of a new topological phase of matter, namely a topological crystalline insulator where space group symmetries replace the role of time-reversal symmetry in an otherwise Z2 topological insulator predicted in theory. We experimentally investigate the possibility of a mirror symmetry protected topological phase transition in the Pb1-xSnxTe alloy system, which has long been known to contain an even number of band inversions based on band theory. Our experimental results show that at a composition below the theoretically predicted band inversion, the system is fully gapped, whereas in the band-inverted regime, the surface exhibits even number of spin-polarized Dirac cone states revealing mirror-protected topological order (Nature Communications 3, 1192 (2012)) distinct from that observed in Z2 topological insulators. We discuss future experimental possibilities opened up by these new developments in topological insulators research. This work is in collaboration with M. Neupane, C. Liu, N. Alidoust, I. Belopolski, D. Qian, D.M. Zhang, A. Richardella, A. Marcinkova, Q

  9. Experimental Studies on Electrical Insulation Performances of SF6/N2 Gas Mixtures%SF6/N2混合气体绝缘特性的实验研究

    孙鹏程; 王帮田; 洪文芳; 王其中


    目前绝大多数气体绝缘开关设备采用SF6气体绝缘,SF6泄漏导致严重的环保问题,人们迫切希望少采用或不采用SF6气体,以降低对环境的污染.为此,试验研究SF6和SF6/N2混合气体在不同混合比、不同压力以及在不同电场结构下的击穿特性,并与SF6气体的绝缘性能进行比较,试验结果表明:在N2中注入20%~30%的SF6气体后,SF6/N2混合气体绝缘性能指标可以达到纯SF6气体的80%左右,但若继续增加SF6气体的配比,则其耐电强度上升的幅度明显变慢;此外,试验研究还发现,极不均匀电场会大大降低气体的耐击穿电压强度 试验研究证明了采用SF6/N2混合气体代替纯SF6气体的技术方案的可行性.%SF6 gas is widely used for gas-insulated switchgear (GIS), which has led to public concerns about environmental pollutions. It is urgently required to reduce or eliminate the use of SF6 gas in GISs so as to reduce the environmental pollutions. Various experiments were conducted to study the electrical breakdown characteristics of SF6 gas and N2/SF6 gas mixtures under different mixing ratios and working pressures and in different electric-field structures. The testing results indicate that the N2/SF6 gas mixture, when 20%-30% of SF6-gas is inputted in N2, can attain 80% of pure SF6 gas in electrical strength, but will have no significant increase in the strength with further increase of SF6-gas ratio. Moreover, it was found that the extremely uneven structure of electric field will significantly reduce the electrical strength of the gas. The testing results has verified the feasibility of SF6/N2 gas mixture in substituting pure SF6 gas.

  10. Electrical performance of silicon-on-insulator field-effect transistors with multiple top-gate organic layers in electrolyte solution.

    Khamaisi, Bassam; Vaknin, Oshri; Shaya, Oren; Ashkenasy, Nurit


    The utilization of field-effect transistor (FET) devices in biosensing applications have been extensively studied in recent years. Qualitative and quantitative understanding of the contribution of the organic layers constructed on the device gate, and the electrolyte media, on the behavior of the device is thus crucial. In this work we analyze the contribution of different organic layers on the pH sensitivity, threshold voltage, and gain of a silicon-on-insulator based FET device. We further monitor how these properties change as function of the electrolyte screening length. Our results show that in addition to electrostatic effects, changes in the amphoteric nature of the surface also affect the device threshold voltage. These effects were found to be additive for the first (3-aminopropyl)trimethoxysilane linker layer and second biotin receptor layer. For the top streptavidin protein layer, these two effects cancel each other. The number and nature of amphoteric groups on the surface, which changes upon the formation of the layers, was shown also to affect the pH sensitivity of the device. The pH sensitivity reduces with the construction of the first two layers. However, after the formation of the streptavidin protein layer, the protein's multiple charged side chains induce an increase in the sensitivity at low ionic strengths. Furthermore, the organic layers were found to influence the device gain due to their dielectric properties, reducing the gain with the successive construction of each layer. These results demonstrate the multilevel influence of organic layers on the behavior of the FET devices.

  11. Magnetically insulated transmission line oscillator

    Bacon, Larry D. (Albuquerque, NM); Ballard, William P. (Albuquerque, NM); Clark, M. Collins (Albuquerque, NM); Marder, Barry M. (Albuquerque, NM)


    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 arfe 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.




    Full Text Available The Gas Insulated Substation (GIS have various advantages like Compactness, immunity from environmental conditions, high operational reliability, low maintenance cost. In a number of GIS installations, the main design considerations involved in gas insulated equipment are at cone insulator, gas and metal interface. Hence there isa need for control of electric stresses in order to reduce internal discharges, surface discharges to the enclosure surface. In conventional approach, in order to reduce such distortion of electric field, many techniques are applied like, control of the spacer shape, additional shielding of electrodes for relaxation of electric field around spacer and low permittivity of spacer material. The new techniques of Functionally Gradient Material (FGMspacer has been proposed in this paper. In this paper the applicability of FGM spacer for gas insulated power apparatus has been verified. In the FGM spacer, a spatial distribution of permittivity for the control of theelectric field distribution in and around the spacer is used. The electric field calculations for several types of FGM spacers have been carried out using Finite Element Method (FEM. The electric field distribution along the radial distance of the spacer insulator have been obtained for various FGM materials and results arecompared.

  13. Estudo da viabilidade de obtenção de isoladores elétricos a partir de resíduo de esmaltação Study of the viability for obtaining electric insulators from enameling waste

    F. J. P. Sousa


    Full Text Available A gestão racional de resíduos industriais é um dos sérios problemas da sociedade atual. O presente trabalho tem por objetivo propor uma alternativa para o aproveitamento do resíduo de esmaltação da empresa Portinari, grupo Cecrisa S.A, por meio da utilização desse resíduo como principal componente em massas cerâmicas para obtenção de isoladores elétricos de distribuição secundária. Foram estudadas formulações contendo no mínimo 50% de resíduo e quantidades variáveis de alumina, feldspato potássico e de quartzo. O resíduo bruto foi primeiramente beneficiado e submetido às analises química, térmica e mineralógica para fins de caracterização. Adotou-se o processo de conformação plástica por torneamento para fabricação das amostras a verde, as quais foram secadas ao ar livre. As amostras obtidas foram submetidas a um ciclo térmico previamente indicado pela curva de gresificação do resíduo. Por fim, após a queima, os protótipos foram ensaiados quanto à rigidez dielétrica. Os resultados indicaram a compatibilidade técnica dos mesmos considerando o uso como isolador.Wise management of industrial wastes is one of the most serious problems in today´s society. The aim of the present work is to suggest an alternative way to reuse the enameling waste of Company Portinari Company, Cecrisa S.A, as major component in ceramic masses to the manufacturing of electric insulators. Formulations with variable amounts of alumina, potassic feldspar and quartz were used, all containing at least 50% waste. The crude waste was firstly treated and then characterized by chemical and mineralogical analysis. The plastic molding process was used in order to produce the green samples, which were left to dry. The samples were submitted to a firing cycle previously indicated by a gresification curve for the waste. After that, the produced samples were submitted to a final test in order to estimate their dielectric rupture tension. The

  14. Insulating and sheathing materials of electric and optical cables: common test methods part 4-1: methods specific to polyethylene and polypropylene compounds – resistance to environmental stress cracking – measurement of the melt flow index – carbon black and/or mineral filler content measurement in polyethylene by direct combustion – measurement of carbon black content by thermogravimetric analysis (TGA) – assessment of carbon black dispersion in polyethylene using a microscope

    International Electrotechnical Commission. Geneva


    Specifies the test methods to be used for testing polymeric insulating and sheathing materials of electric cables for power distribution and telecommunications including cables used on ships. Gives the methods for measurements of the resistance to environmental stress cracking, for wrapping test after thermal ageing in air, for measurement of melt flow index and for measurement of carbon black and/or mineral filler content, which apply to PE and PP coumpounds, including cellular compounds and foam skin for insulation.

  15. 49 CFR 229.81 - Emergency pole; shoe insulation.


    ... 49 Transportation 4 2010-10-01 2010-10-01 false Emergency pole; shoe insulation. 229.81 Section... ADMINISTRATION, DEPARTMENT OF TRANSPORTATION RAILROAD LOCOMOTIVE SAFETY STANDARDS Safety Requirements Electrical System § 229.81 Emergency pole; shoe insulation. (a) Each locomotive equipped with a pantograph...

  16. High Field Electrical Conduction in Pre-Formed Al-ZnS-Al Thin Films in Metal-Insulator-Metal Devices

    M. Y. Nadee; Nadeem Iqbal; M. F. Wasiq; A. U. Khosa


    The high field electrical conduction mechanism for the widely used ZnS thin films in the microelectronic industry is investigated. Experimental data on the dc conduction as a function of the applied bias for the Al-ZnS-Al devices is carefully compared with the theoretical equations given by Schottky and Poole-Frenkel. The results yield the value of the coefficient of the barrier lowering compatible with the Schottky theory rather than the Poole-Frenkel theory, which are also in agreement with the results reported earlier by Maskawa [Phys. Rev. Lett.24(1970) 1175

  17. Topological Insulator Realized with Piezoelectric Resonators

    McHugh, S.


    We propose a realization of a two-dimensional topological insulator using an array of microwave piezoelectric resonators. The resonators are coupled electrically, but acoustically isolated. The inter-resonator electromagnetic coupling required to reproduce an effective mechanical topological insulator is found explicitly. Both the acoustic and electric response show the essential features of topological insulator, e.g., helical edge states. The helical edge states may be useful for engineering nonreciprocal electronic devices like isolators and circulators. These components do not often appear in the radios of modern mobile phones since they traditionally require bulky magnetic material. However, a nonreciprocal device based on piezoelectric resonators may meet the demands of phone manufacturers due to their small size, high-linearity, and ease of fabrication.

  18. Structure Change of the Insulating Composite

    Vaclav Mentlik


    Full Text Available Modern power electric drives brought advantages in induction motor control. In the same time appeared problems with high frequency square waveform voltage (pulse stress produced by the voltage converters. Voltage converters produce repetitive pulses with high level of voltage rise fronts (slew rates. Rise fronts attained values of up to tens kilovolts per microsecond and voltage pulse repetition frequency up to some tens of kilohertz. This technology is an advantage for a drive control. Significant is the impact of these voltage waveforms on the motor insulations. Degradation of the main wall insulation can reduce the reliability of the electric motor and whole drive. In this paper is discussed one possible solution. The promising modification in the insulation material structure is presented in the paper.

  19. Electrical properties and transport mechanisms of Au/Ba0.6Sr0.4TiO3/GaN metal-insulator-semiconductor (MIS) diode at high temperature range

    Rajagopal Reddy, V.


    The electrical and transport mechanisms of a fabricated Au/Ba0.6Sr0.4TiO3 (BST)/GaN metal-insulator-semiconductor (MIS) diode have been studied in the temperature range of 280-430 K by current-voltage ( I- V) and capacitance-voltage ( C- V) measurements. The barrier heights (BHs) of the Au/BST/GaN MIS diode are found to be 0.85 eV ( I- V)/1.35 ( C- V) at 280 K and 1.14 eV ( I- V)/1.17 ( C- V) at 430 K. The series resistance ( R S) values determined by Cheung's functions are in good agreement with each other. The difference between BHs estimated by I- V and C- V methods are also discussed. Results show that the estimated interface state density ( N SS) of MIS diode decreases with an increase in temperature. Observations have indicated that the BH increases whereas ideality factor R S and N SS decreases with increasing temperature. Results have demonstrated that the reverse leakage current is dominated by Poole-Frenkel emission at temperatures of 280-340 K and by Schottky emission at temperatures of 370-430 K. It is also noted that there is a transition of the conduction mechanism in Au/BST/GaN MIS diode from Poole-Frenkel to Schottky emission at temperatures of 340-370 K.


    L. Suboch


    Full Text Available Problems concerning development of composite insulators and insulator types for electric mains with a voltage higher than 1000 kV in the Western Europe are considered in the paper. It shows the prospects for obtaining a number of polymer materials (epoxy resin, silicone elastomer, ethylene-propylene rubber, polytetraftuoroethylene etc., reinforcing materials and ageing problem of polymer insulation.

  1. Electric field analysis

    Chakravorti, Sivaji


    This book prepares newcomers to dive into the realm of electric field analysis. The book details why one should perform electric field analysis and what are its practical implications. It emphasizes both the fundamentals and modern computational methods of electric machines. The book covers practical applications of the numerical methods in high voltage equipment, including transmission lines, power transformers, cables, and gas insulated systems.

  2. Conformally encapsulated multi-electrode arrays with seamless insulation

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


    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.

  3. Fabrication and performance testing of CaO insulator coatings on V-5%Cr-5%Ti in liquid lithium

    Park, J.H.; Dragel, G. [Argonne National Lab., Chicago, IL (United States)


    Corrosion resistance of structural materials, and the magnetohydrodynamic (MHD) force and its influence on thermal hydraulics and corrosion, are major concerns in the design of liquid-metal blankets for magnetic fusion reactors (MFRs). The objective of this study is to develop in-situ stable coatings at the liquid-metal/structural-material interface, with emphasis on coatings that can be converted to an electrically insulating film to prevent adverse currents that are generated by the MHD force from passing through the structural walls. The electrical resistance of CaO coatings produced on V-5Cr-5Ti by exposure of the alloy to liquid Li that contained 0.5 - 8.5 wt.% dissolved Ca was measured as a function of time at temperatures between 250 and 600{degree}C. The solute element, Ca in liquid Li, reacted with the alloy substrate at 400-420{degree}C to produce a CaO coating.

  4. Heat Transfer through Cable Insulation of Nb–Ti Superconducting Magnets Operating in He II

    Granieri, P P


    The operation of Nb–Ti superconducting magnets in He II relies on superfluidity to overcome the severe thermal barrier represented by the cable electrical insulation. In wrapped cable insulations, like those used for the main magnets of the Large Hadron Collider (LHC) particle accelerator, the micro-channels network created by the insulation wrappings allows to efficiently transfer the heat deposited or generated in the cable to the He bath. In this paper, available experimental data of heat transfer through polyimide electrical insulation schemes are analyzed. A steady-state thermal model is developed to describe the insulation of the LHC main dipole magnets and the Enhanced Insulation proposed for the High Luminosity LHC upgrade (HL-LHC), according to the relevant geometric parameters. The model is based on the coupled mechanisms of heat transfer through the bulk of the dielectric insulation and through micro-channels between the insulation tapes. A good agreement is found between calculations and tests p...

  5. Strongly Correlated Topological Insulators


    Research Triangle Park , NC 27709-2211 Condensed Matter, Topological Phases of Matter REPORT DOCUMENTATION PAGE 11. SPONSOR/MONITOR’S REPORT NUMBER(S...Strongly Correlated Topological Insulators In the past year, the grant was used for work in the field of topological phases, with emphasis on finding...surface of topological insulators. In the past 3 years, we have started a new direction, that of fractional topological insulators. These are materials

  6. Electrical Properties and Interfacial Studies of HfxTi1–xO2 High Permittivity Gate Insulators Deposited on Germanium Substrates

    Qifeng Lu


    Full Text Available In this research, the hafnium titanate oxide thin films, TixHf1–xO2, with titanium contents of x = 0, 0.25, 0.9, and 1 were deposited on germanium substrates by atomic layer deposition (ALD at 300 °C. The approximate deposition rates of 0.2 Å and 0.17 Å per cycle were obtained for titanium oxide and hafnium oxide, respectively. X-ray Photoelectron Spectroscopy (XPS indicates the formation of GeOx and germanate at the interface. X-ray diffraction (XRD indicates that all the thin films remain amorphous for this deposition condition. The surface roughness was analyzed using an atomic force microscope (AFM for each sample. The electrical characterization shows very low hysteresis between ramp up and ramp down of the Capacitance-Voltage (CV and the curves are indicative of low trap densities. A relatively large leakage current is observed and the lowest leakage current among the four samples is about 1 mA/cm2 at a bias of 0.5 V for a Ti0.9Hf0.1O2 sample. The large leakage current is partially attributed to the deterioration of the interface between Ge and TixHf1–xO2 caused by the oxidation source from HfO2. Consideration of the energy band diagrams for the different materials systems also provides a possible explanation for the observed leakage current behavior.

  7. Effect of Stress on Transformer Insulation

    Kapil Gandhi


    Full Text Available Power transformers use Kraft paper as insulation in the electrical windings present in the core, which is immersed in oil. In service, the temperature of the windings of core will go to 750C to 850C. If the transformer is over loaded, then the temperature can exceed upto 100°C causing the cellulose chains in the paper to cleave at an accelerated rate, which results in the degradation of mechanical strength and performance of the insulation. The Degree of Polymerization (DP will also decrease. If proper action will not take, this can lead to failure of the transformer and disruption to electricity supply and large economic losses to the operating utility. Transformer condition should be maintained because of its importance to electricity network. The life of transformer depends on the life of the oil impregnated paper insulation system to greater extent. Degradation of the cellulose insulation is an irreversible process. After thermal degradation of the paper winding, Furfuraldehyde (FFA is the chemical compound, which is released into the oil from paper. The concentration of FFA has been directly related to the condition of the paper insulation. In the present paper an experimental investigation has been made to evaluate the degradation of transformer oil contaminated by nano-particles of pine wood under accelerated thermal and electrical stress and results are correlated with breakdown strength, density & interfacial tension of the pure oil. The contaminated oil samples are tested at electric stress of 2.0 kV, 3.0 kV, 4.0 kV & 5.0 kV for 24, 48, 72 & 96 hours simultaneously.

  8. Comparative study of surrounding electric field distribution of composite insulator with different disc diameter under pollution state%污秽状态下不同盘径复合绝缘子周围电场分布的比较研究

    张宏军; 王锋; 温定筠; 张秀斌


    In recent years, insulator flashover occurred repeatedly in the northwest power grid, and caused tripping accidents and a large economic losses, which is a major risk for the reliability of power supply. Contamination on the surface of insulators is one of main reasons causing flashover. In this pa-per, the electric field distribution of 330 kV line composite insulator which covered by contamination was studied used finite element method. It was analyzed that distribution of potential and electric field of com-posite insulator covered different contamination. The effects of conductivity of pollution layer on the distri-bution of potential and electric field of composite insulator was studied. It was compared that electric field distributions of composite insulators cover by uniform and non-uniform pollution layers.%近年来,西北电网多次发生绝缘子闪络跳闸事故,对电网供电可靠性造成了重大影响,经济损失很大。绝缘子表面聚集的污秽是引起闪络的主要原因之一。该文应用有限元法对西北电网两种不同盘径的330 kV线路悬式复合绝缘子进行了建模,并对污秽状态下的电场分布进行了仿真和比较。分析了不同污秽情况下此两种不同盘径复合绝缘子的电位、电场分布情况;研究了污层电导率对复合绝缘子电位、电场分布的影响;对比了污层均匀分布和不均匀分布对复合绝缘子表面电场分布的影响;研究了不同盘径绝缘子组合下绝缘子串的污秽承受能力。

  9. Composite Flexible Blanket Insulation

    Kourtides, Demetrius A. (Inventor); Pitts, William C. (Inventor); Goldstein, Howard E. (Inventor); Sawko, Paul M. (Inventor)


    Composite flexible multilayer insulation systems (MLI) were evaluated for thermal performance and compared with the currently used fibrous silica (baseline) insulation system. The systems described are multilayer insulations consisting of alternating layers of metal foil and scrim ceramic cloth or vacuum metallized polymeric films quilted together using ceramic thread. A silicon carbide thread for use in the quilting and the method of making it are also described. These systems are useful in providing lightweight insulation for a variety of uses, particularly on the surface of aerospace vehicles subject to very high temperatures during flight.

  10. Plasmonics in Topological Insulators

    Yi-Ping Lai


    Full Text Available With strong spin-orbit coupling, topological insulators have an insulating bulk state, characterized by a band gap, and a conducting surface state, characterized by a Dirac cone. Plasmons in topological insulators show high frequency-tunability in the mid-infrared and terahertz spectral regions with transverse spin oscillations, also called “spin-plasmons”. This paper presents a discussion and review of the developments in this field from the fundamental theory of plasmons in bulk, thin-film, and surface-magnetized topological insulators to the techniques of plasmon excitation and future applications.

  11. Fusion - An energy source for synthetic fuels

    Fillo, J. A.; Powell, J.; Steinberg, M.


    An important first step in the synthesis of liquid and gaseous fuels is the production of hydrogen. Thermonuclear fusion offers an inexhaustible source of energy for the production of hydrogen from water. Depending on design, electric generation efficiencies of 40 to 60% and hydrogen production efficiencies by high temperature electrolysis of 50 to 70% are projected for fusion reactors using high temperature blankets. Fusion/coal symbiotic systems appear economically promising for the first generation of commercial fusion synfuels plants. In the long term, there could be a gradual transition to an inexhaustible energy system based solely on fusion.

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

    Wang, Jingang; Chong, Junlong; Yang, Jie


    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.

  13. Silicon on insulator with active buried regions

    McCarthy, A.M.


    A method is disclosed for forming patterned buried components, such as collectors, sources and drains, in silicon-on-insulator (SOI) devices. The method is carried out by epitaxially growing a suitable sequence of single or multiple etch stop layers ending with a thin silicon layer on a silicon substrate, masking the silicon such that the desired pattern is exposed, introducing dopant and activating in the thin silicon layer to form doped regions. Then, bonding the silicon layer to an insulator substrate, and removing the silicon substrate. The method additionally involves forming electrical contact regions in the thin silicon layer for the buried collectors. 10 figs.

  14. Cold fusion

    Suh, Suk Yong; Sung, Ki Woong; Kang, Joo Sang; Lee, Jong Jik [Korea Atomic Energy Research Institute, Taejon (Korea, Republic of)


    So called `cold fusion phenomena` are not confirmed yet. Excess heat generation is very delicate one. Neutron generation is most reliable results, however, the records are erratic and the same results could not be repeated. So there is no reason to exclude the malfunction of testing instruments. The same arguments arise in recording {sup 4}He, {sup 3}He, {sup 3}H, which are not rich in quantity basically. An experiment where plenty of {sup 4}He were recorded is attached in appendix. The problem is that we are trying to search cold fusion which is permitted by nature or not. The famous tunneling effect in quantum mechanics will answer it, however, the most fusion rate is known to be negligible. The focus of this project is on the theme that how to increase that negligible fusion rate. 6 figs, 4 tabs, 1512 refs. (Author).

  15. Spinal Fusion

    ... results in predictable healing. Autograft is currently the “gold standard” source of bone for a fusion. The ... pump. With this technique, the patient presses a button that delivers a predetermined amount of narcotic pain ...

  16. Translucent insulating building envelope

    Rahbek, Jens Eg


    A new type of translucent insulating material has been tested. This material is made of Celulose-Acetat and have a honey-comb structure. The material has a high solar transmittance and is highly insulating. The material is relatively cheap to produce. Danish Title: Translucent isolerende klimaskærm....

  17. Translucent insulating building envelope

    Rahbek, Jens Eg


    A new type of translucent insulating material has been tested. This material is made of Celulose-Acetat and have a honey-comb structure. The material has a high solar transmittance and is highly insulating. The material is relatively cheap to produce. Danish Title: Translucent isolerende klimaskærm....

  18. Sound Insulation between Dwellings

    Rasmussen, Birgit


    Regulatory sound insulation requirements for dwellings exist in more than 30 countries in Europe. In some countries, requirements have existed since the 1950s. Findings from comparative studies show that sound insulation descriptors and requirements represent a high degree of diversity...... and initiate – where needed – improvement of sound insulation of new and existing dwellings in Europe to the benefit of the inhabitants and the society. A European COST Action TU0901 "Integrating and Harmonizing Sound Insulation Aspects in Sustainable Urban Housing Constructions", has been established and runs...... 2009-2013. The main objectives of TU0901 are to prepare proposals for harmonized sound insulation descriptors and for a European sound classification scheme with a number of quality classes for dwellings. Findings from the studies provide input for the discussions in COST TU0901. Data collected from 24...

  19. Sound insulation between dwellings

    Rasmussen, Birgit


    Regulatory sound insulation requirements for dwellings exist in more than 30 countries in Europe. In some countries, requirements have existed since the 1950s. Findings from comparative studies show that sound insulation descriptors and requirements represent a high degree of diversity...... and initiate – where needed – improvement of sound insulation of new and existing dwellings in Europe to the benefit of the inhabitants and the society. A European COST Action TU0901 "Integrating and Harmonizing Sound Insulation Aspects in Sustainable Urban Housing Constructions", has been established and runs...... 2009-2013. The main objectives of TU0901 are to prepare proposals for harmonized sound insulation descriptors and for a European sound classification scheme with a number of quality classes for dwellings. Findings from the studies provide input for the discussions in COST TU0901. Data collected from 24...

  20. Simulation of the aging process of insulating systems variable frequency drive

    Garganeev, A.; Leonov, A.; Merkulov, V.; Charkov, D.


    The paper deals with the intensity of the model in the electrical insulation variable frequency drive controlled at different temperatures and electric fields. It is shown that aging of insulation mechanism associated with the development of corona discharges caused by transients when the frequency adjustment. Laws aging of insulation can be described from the point of view of the theory of thermal destruction of dielectrics vibrations.

  1. Carbon nanofillers for machining insulating ceramics

    Olivier Malek


    Full Text Available The implementation of ceramics in emerging applications is principally limited by the final machining process necessary for producing microcomponents with complex geometries. The addition of carbon nanotubes greatly enhances the electrical properties of insulating ceramics allowing electrical discharge machining to be used to manufacture intricate parts. Meanwhile other properties of the ceramic may be either preserved or even improved. For the first time, a silicon nitride/carbon nanotubes microgear is electrically discharge machined with a remarkably high material removal rate, low surface roughness, and low tool wear. This offers unprecedented opportunities for the manufacture of complicated ceramic parts by adding carbon nanotubes for new engineering and biomedical applications.

  2. Electrodynamic thermal breakdown of a capacitor insulator

    Emel'Yanov, O. A.


    A mechanism of the electrical breakdown is proposed for modern metal-field capacitors with the well-known property of self-healing of the breakdown strength. Upon an increase in the working voltage, the self-healing time increases to tens of microseconds, and the heating of adjacent insulator layers becomes significant. The propagating thermally activated conduction wave facilitates the enhancement of the electric field up to breakdown values. Analysis of the dynamics of electric field increase is carried out for capacitors based on polyethylene terephthalate (PET) dielectric.

  3. Intense fusion neutron sources

    Kuteev, B. V.; Goncharov, P. R.; Sergeev, V. Yu.; Khripunov, V. I.


    The review describes physical principles underlying efficient production of free neutrons, up-to-date possibilities and prospects of creating fission and fusion neutron sources with intensities of 1015-1021 neutrons/s, and schemes of production and application of neutrons in fusion-fission hybrid systems. The physical processes and parameters of high-temperature plasmas are considered at which optimal conditions for producing the largest number of fusion neutrons in systems with magnetic and inertial plasma confinement are achieved. The proposed plasma methods for neutron production are compared with other methods based on fusion reactions in nonplasma media, fission reactions, spallation, and muon catalysis. At present, intense neutron fluxes are mainly used in nanotechnology, biotechnology, material science, and military and fundamental research. In the near future (10-20 years), it will be possible to apply high-power neutron sources in fusion-fission hybrid systems for producing hydrogen, electric power, and technological heat, as well as for manufacturing synthetic nuclear fuel and closing the nuclear fuel cycle. Neutron sources with intensities approaching 1020 neutrons/s may radically change the structure of power industry and considerably influence the fundamental and applied science and innovation technologies. Along with utilizing the energy produced in fusion reactions, the achievement of such high neutron intensities may stimulate wide application of subcritical fast nuclear reactors controlled by neutron sources. Superpower neutron sources will allow one to solve many problems of neutron diagnostics, monitor nano-and biological objects, and carry out radiation testing and modification of volumetric properties of materials at the industrial level. Such sources will considerably (up to 100 times) improve the accuracy of neutron physics experiments and will provide a better understanding of the structure of matter, including that of the neutron itself.

  4. Topological Field Theory of Time-Reversal Invariant Insulators

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


    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.

  5. Study on Insulating Material by Renewable Resources

    Kurata, Yasuyuki; Kurosumi, Akihiro; Ishikawa, Keita

    Under circumstances such as global warming caused by carbon dioxide and other green house gas and crisis of depletion of fossil resources, recyclable resources such as biomass have captured the world's attention as reproducible resources alternative to petroleum. Therefore the technologies such to manufacture chemicals from recyclable resources have been developed for the achievement of measures for controlling global warming and the low carbon society. Recently, the bioplastic such as polylactic resin is applied to the home appliances and the automobile interior part as substitution of general-purpose plastic Moreover, the insulation oil from the vegetable oil has been put to practical use. The application of recyclable resources is extending in an electric field. In this paper, we introduce the characteristic and the problem of the insulating material made from recyclable resources in the field of the solid insulation.

  6. Insulating Foams Save Money, Increase Safety


    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.

  7. Optimisation of Multilayer Insulation an Engineering Approach

    Chorowski, M; Parente, C; Riddone, G


    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.

  8. SF6新气痕量杂质对SF6电气设备寿命的影响%Influence of Trace Impurities from SF6 New Gas on the Life of SF6-insulating Electrical Equipment

    裘吟君; 袁静帆; 陈晓琳


    In order to provide references for quality control of new SF6 gas in electrical equipment, the influence of trace impurities in new SF6 gases on SF6-insulating electrical equipment was experimentally investigated. An internal default as metal point discharge on the center rod was simulated by using a straight-line isolator installment which shared gas chamber with a current transformer. Then experiments of using SF6 new gas with various qualities under 2 voltage modes, single 220 kV single voltage mode and 220 kV/3 150 A synchronous upward current-voltage mode, were performed for about 100 h. In the experiments, variations of volume concentration of each impurity in the SF6 gases were detected by a gas chromatography mass spectrometry analyzer and a DPD SF6 impurity analyzer ( made in Canada). The results show that, more by-products like SO2F2 , S()F2 , and SO, will be generated when electrical equipment is filled with new SF6 gas which has mass trace impurities, including fluorinated alkane, fluorizating sulfonyl, and carbon sulfur fluoride; considering the corrosive effect of SO2 on the equipment, it is concluded that when SFS is filled with new gas with high level impurities, the life of electrical equipment will be shortened , especially that of breaks will be shortened.%为了给电气设备中的SF6新气质量控制提供参考,研究了SF6新气中痕量杂质对电气设备运行寿命的影响.通过一个与电流互感器共气室的直线隔离开关装置,模拟了中心导杆上金属尖端放电内部缺陷.在220 kV单电压和220 kV、3 150 A同步升流升压2种方式下,分别充入不同品质的SF6新气进行约100 h的试验.并采用SF6气相色谱质谱分析技术、加拿大SF6杂质分析仪DPD,跟踪检测SF6气体痕量杂质各组分体积分数变化情况.结果表明,设备中充入低品质SF6新气(含有较高浓度的全氟烷烃、氟化硫酰、及碳硫氟化物等多种杂质),在放电末期产生较多的SO2R、SOF2

  9. Electrical installations technology

    Whitfield, J F


    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

  10. Common test methods for insulating and sheathing materials of electric cables part 1-1: methods for general application : measurement of thickness and overall dimensions : tests for determining the mechanical properties

    International Electrotechnical Commission. Geneva


    Gives the methods for measuring thicknesses and overall dimensions, and for determining the mechanical properties, which apply to the most common types of insulating and sheathing compounds (elastometic, PVC, PE, PP, etc.).

  11. Trophoblast fusion.

    Huppertz, Berthold; Gauster, Martin


    The villous trophoblast of the human placenta is the epithelial cover of the fetal chorionic villi floating in maternal blood. This epithelial cover is organized in two distinct layers, the multinucleated syncytiotrophoblast directly facing maternal blood and a second layer of mononucleated cytotrophoblasts. During pregnancy single cytotrophoblasts continuously fuse with the overlying syncytiotrophoblast to preserve this end-differentiated layer until delivery. Syncytial fusion continuously supplies the syncytiotrophoblast with compounds of fusing cytotrophoblasts such as proteins, nucleic acids and lipids as well as organelles. At the same time the input of cytotrophoblastic components is counterbalanced by a continuous release of apoptotic material from the syncytiotrophoblast into maternal blood. Fusion is an essential step in maintaining the syncytiotrophoblast. Trophoblast fusion was shown to be dependant on and regulated by multiple factors such as fusion proteins, proteases and cytoskeletal proteins as well as cytokines, hormones and transcription factors. In this chapter we focus on factors that may be involved in the fusion process of trophoblast directly or that may prepare the cytotrophoblast to fuse.

  12. Microsphere Insulation Panels

    Mohling, R.; Allen, M.; Baumgartner, R.


    Microsphere insulation panels (MIPs) have been developed as lightweight, longlasting replacements for the foam and vacuum-jacketed systems heretofore used for thermally insulating cryogenic vessels and transfer ducts. The microsphere core material of a typical MIP consists of hollow glass bubbles, which have a combination of advantageous mechanical, chemical, and thermal-insulation properties heretofore available only separately in different materials. In particular, a core filling of glass microspheres has high crush strength and low density, is noncombustible, and performs well in soft vacuum.

  13. Pulsed Power Driven Fusion Energy



    Pulsed power is a robust and inexpensive technology for obtaining high powers. Considerable progress has been made on developing light ion beams as a means of transporting this power to inertial fusion capsules. However, further progress is hampered by the lack of an adequate ion source. Alternatively, z-pinches can efficiently convert pulsed power into thermal radiation, which can be used to drive an inertial fusion capsule. However, a z-pinch driven fusion explosion will destroy a portion of the transmission line that delivers the electrical power to the z-pinch. They investigate several options for providing standoff for z-pinch driven fusion. Recyclable Transmission Lines (RTLs) appear to be the most promising approach.

  14. High-voltage cable insulation online monitoring in coal mine based on pattern recognition

    Zhao, Yongmei; Li, Junfeng; Wu, Lingjie; Wang, Yanwen


    The single-phase grounding fault is the main electrical fault types of the mine power grid. A new cable insulation online monitoring based on pattern recognition is proposed, in case single-phase grounding fault in coal mine. Firstly, using the pattern recognition method, the insulation state of the cable is divided into three types: "good insulation" and "insulation decline symmetrically" and "insulation decline asymmetrically". Then the cables with "insulation decline asymmetrically" can be further analysed and calculated and its insulation parameter value can be determined. The algorithm is simulated and verified. Simulation result shows that: The zero-sequence voltage and each phase voltage and the zero-sequence current of each cable are taken in the coal mine high-voltage system, and the insulation parameter value of each cable can be calculated accurately by using the pattern recognition method.

  15. Topological insulators: Engineered heterostructures

    Hesjedal, Thorsten; Chen, Yulin


    The combination of topological properties and magnetic order can lead to new quantum states and exotic physical phenomena. In particular, the coupling between topological insulators and antiferromagnets enables magnetic and electronic structural engineering.

  16. Gas insulated substations


    This book provides an overview on the particular development steps of gas insulated high-voltage switchgear, and is based on the information given with the editor's tutorial. The theory is kept low only as much as it is needed to understand gas insulated technology, with the main focus of the book being on delivering practical application knowledge. It discusses some introductory and advanced aspects in the meaning of applications. The start of the book presents the theory of Gas Insulated Technology, and outlines reliability, design, safety, grounding and bonding, and factors for choosing GIS. The third chapter presents the technology, covering the following in detail: manufacturing, specification, instrument transformers, Gas Insulated Bus, and the assembly process. Next, the book goes into control and monitoring, which covers local control cabinet, bay controller, control schemes, and digital communication. Testing is explained in the middle of the book before installation and energization. Importantly, ...

  17. Repairing ceramic insulating tiles

    Dunn, B. R.; Laymance, E. L.


    Fused-silica tiles containing large voids or gauges are repaired without adhesives by plug insertion method. Tiles are useful in conduits for high-temperature gases, in furnaces, and in other applications involving heat insulation.

  18. Development scenario for laser fusion

    Maniscalco, J.A.; Hovingh, J.; Buntzen, R.R.


    This scenario proposes establishment of test and engineering facilities to (1) investigate the technological problems associated with laser fusion, (2) demonstrate fissile fuel production, and (3) demonstrate competitive electrical power production. Such facilities would be major milestones along the road to a laser-fusion power economy. The relevant engineering and economic aspects of each of these research and development facilities are discussed. Pellet design and gain predictions corresponding to the most promising laser systems are presented for each plant. The results show that laser fusion has the potential to make a significant contribution to our energy needs. Beginning in the early 1990's, this new technology could be used to produce fissile fuel, and after the turn of the century it could be used to generate electrical power.

  19. Virtual experiment of pyroelectric fusion

    Nasseri, Mohammad Mehdi, E-mail:


    The virtual experiment of pyroelectric fusion was conducted by Geant4 simulator. Despite the limitations of the code for simulating the pyroelectric fusion experiment precisely, the following interesting results were obtained. Two crystals were separated by a certain distance. A constant electric field with varying intensities was applied between the crystals. As initial particles, deuterium ions were emitted to deuterated polypropylene (CD{sub 2}). This virtual experiment showed that the number of ions that hit the target, for different distances between the crystals, increases with the increase of the intensity of the electric field; however, further increase of the electric field results in the reduction of the number of hit ions, which attains a constant value of about 57% of the initial number of ions. For a (D, D) fusion reaction to occur, the distance between the two crystals should be <1.5 cm and for a (D, T) fusion reaction to occur, this distance could be up to 2 cm. The energy spectra of ions for low and high electric fields were narrow and long and wide and short, respectively.

  20. Technical issues for beryllium use in fusion blanket applications

    McCarville, T.J.; Berwald, D.H.; Wolfer, W.; Fulton, F.J.; Lee, J.D.; Maninger, R.C.; Moir, R.W.; Beeston, J.M.; Miller, L.G.


    Beryllium is an excellent non-fissioning neutron multiplier for fusion breeder and fusion electric blanket applications. This report is a compilation of information related to the use of beryllium with primary emphasis on the fusion breeder application. Beryllium resources, production, fabrication, properties, radiation damage and activation are discussed. A new theoretical model for beryllium swelling is presented.

  1. Novel Method for Electric Field Calculation Considering the Thickness of Contaminant Layer on the Surface of Composite Insulator%含污秽薄层的高压复合绝缘子表面电场计算新方法

    汪沨; 廖平军; 黄俊; 罗勇; 肖运军


    To study the mechanism of composite insulator pollution flashover, electric field analysis of the polluted composite insulators is required. However, the thickness of the contamination layer is only a fraction of millimeter that is much smaller than the size of insulator itself. Consequently, neither the finite element method nor boundary element method can solve such field problems with multiple scales at present. Therefore, This paper proposes a new method to calculate the surface electric field of polluted insulator based on the digital image processing. First, binary image processing is applied to the image of insulator with sizem×n, and regional meshing is realized at each the pixel unit. Meanwhile, a mathematical model of impedance is established based on pixel unit. Then the node admittance matrix of size (m×n)×(m×n) is formed. The distribution of surface electric field of polluted insulator is calculated by electrical network analysis using node voltage method. The example shows that, compared with the existing algorithms, this method has significant advantages and improved effectiveness for modeling filthy layer which revealed contamination mechanism of composite insulator surface flashover, corona discharge, etc.%为研究复合绝缘子污闪机理,需对含污层的复合绝缘子进行电场分析,然而绝缘子表面污秽层厚度数量级达10?4m,甚至更小,远远小于绝缘子的尺寸.目前现有的有限元及边界元电场计算方法都无法解决此类多空间尺度的场域分析问题.为此,提出一种基于数字图像处理的污秽绝缘子表面电场计算新方法,该方法首先应用图像处理技术对m×n大小绝缘子图像二值化处理,利用像素单元实现区域的网格剖分,同时在像素单元基础上建立阻抗数学模型;然后形成(m×n)×(m×n)大小的节点导纳矩阵,采取节点电压法对其进行电网络分析,得到污秽绝缘子表面电场分布.实例计算表

  2. Standard Specification for Electric Fusion-Welded Ni-Cr-Co-Mo Alloy (UNS N06617), Ni-Fe-Cr-Si Alloys (UNS N08330 and UNS N08332), Ni-Cr-Fe-Al Alloy (UNS N06603), Ni-Cr-Fe Alloy (UNS N06025), and Ni-Cr-Fe-Si Alloy (UNS N06045) Pipe

    American Society for Testing and Materials. Philadelphia


    Standard Specification for Electric Fusion-Welded Ni-Cr-Co-Mo Alloy (UNS N06617), Ni-Fe-Cr-Si Alloys (UNS N08330 and UNS N08332), Ni-Cr-Fe-Al Alloy (UNS N06603), Ni-Cr-Fe Alloy (UNS N06025), and Ni-Cr-Fe-Si Alloy (UNS N06045) Pipe

  3. Magnet Design Considerations for Fusion Nuclear Science Facility

    Zhai, Y. [Princeton Plasma Physics Lab. (PPPL), Princeton, NJ (United States); Kessel, C. [Princeton Plasma Physics Lab. (PPPL), Princeton, NJ (United States); El-Guebaly, L. [Univ. of Wisconsin, Madison, WI (United States) Fusion Technology Institute; Titus, P. [Princeton Plasma Physics Lab. (PPPL), Princeton, NJ (United States)


    The Fusion Nuclear Science Facility (FNSF) is a nuclear confinement facility that provides a fusion environment with components of the reactor integrated together to bridge the technical gaps of burning plasma and nuclear science between the International Thermonuclear Experimental Reactor (ITER) and the demonstration power plant (DEMO). Compared with ITER, the FNSF is smaller in size but generates much higher magnetic field, i.e., 30 times higher neutron fluence with three orders of magnitude longer plasma operation at higher operating temperatures for structures surrounding the plasma. Input parameters to the magnet design from system code analysis include magnetic field of 7.5 T at the plasma center with a plasma major radius of 4.8 m and a minor radius of 1.2 m and a peak field of 15.5 T on the toroidal field (TF) coils for the FNSF. Both low-temperature superconductors (LTS) and high-temperature superconductors (HTS) are considered for the FNSF magnet design based on the state-of-the-art fusion magnet technology. The higher magnetic field can be achieved by using the high-performance ternary restacked-rod process Nb3Sn strands for TF magnets. The circular cable-in-conduit conductor (CICC) design similar to ITER magnets and a high-aspect-ratio rectangular CICC design are evaluated for FNSF magnets, but low-activation-jacket materials may need to be selected. The conductor design concept and TF coil winding pack composition and dimension based on the horizontal maintenance schemes are discussed. Neutron radiation limits for the LTS and HTS superconductors and electrical insulation materials are also reviewed based on the available materials previously tested. The material radiation limits for FNSF magnets are defined as part of the conceptual design studies for FNSF magnets.

  4. Summary of the 9th IEA workshop on radiation effects in ceramic insulators

    Zinkle, S.J. [Oak Ridge National Lab., TN (United States); Hodgson, E.R.; Shikama, T.


    Twenty one scientists attended an IEA workshop in Cincinnati, Ohio on May 8-9, 1997, which was mainly devoted to reviewing the current knowledge base on the phenonenon of radiation induced electrical degradation in ceramic insulators. Whereas convincing evidence for bulk RIED behavior has been observed by two research groups in sapphire after electron irradiation, definitive levels of bulk RIED have not been observed in high purity Al{sub 2}O{sub 3} by several research groups during energetic ion or fission neutron irradiation. Possible reasons for the conflicting RIED results obtained by different research groups were discussed. It was conducted that RIED does not appear to be of immediate concern for near-term fusion devices such as ITER. However, continued research on the RIED phenomenon with particular emphasis on electron irradiations of single crystal alumina was recommended in order to determine the underlying physical mechanisms. This will allow a better determination of whether RIED might occur under any of the widely varying experimental conditions in a fusion energy device. Several critical issues which are recommended for future study were outlined by the workshop attendees.

  5. Magnetic fusion; La fusion magnetique



    This document is a detailed lecture on thermonuclear fusion. The basic physics principles are recalled and the technological choices that have led to tokamaks or stellarators are exposed. Different aspects concerning thermonuclear reactors such as safety, economy and feasibility are discussed. Tore-supra is described in details as well as the ITER project.

  6. Alternative approaches to fusion. [reactor design and reactor physics for Tokamak fusion reactors

    Roth, R. J.


    The limitations of the Tokamak fusion reactor concept are discussed and various other fusion reactor concepts are considered that employ the containment of thermonuclear plasmas by magnetic fields (i.e., stellarators). Progress made in the containment of plasmas in toroidal devices is reported. Reactor design concepts are illustrated. The possibility of using fusion reactors as a power source in interplanetary space travel and electric power plants is briefly examined.

  7. Cold nuclear fusion reactor and nuclear fusion rocket

    Huang Zhenqiang


    Full Text Available "Nuclear restraint inertial guidance directly hit the cold nuclear fusion reactor and ion speed dc transformer" [1], referred to as "cold fusion reactor" invention patents, Chinese Patent Application No. CN: 200910129632.7 [2]. The invention is characterized in that: at room temperature under vacuum conditions, specific combinations of the installation space of the electromagnetic field, based on light nuclei intrinsic magnetic moment and the electric field, the first two strings of the nuclei to be bound fusion on the same line (track of. Re-use nuclear spin angular momentum vector inherent nearly the speed of light to form a super strong spin rotation gyro inertial guidance features, to overcome the Coulomb repulsion strong bias barrier to achieve fusion directly hit. Similar constraints apply nuclear inertial guidance mode for different speeds and energy ion beam mixing speed, the design of ion speed dc transformer is cold fusion reactors, nuclear fusion engines and such nuclear power plants and power delivery systems start important supporting equipment, so apply for a patent merger

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

    Groenland, A.W.; Wolters, R.A.M.; Kovalgin, A.Y.; Schmitz, J.


    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 M

  9. Radiation-induced electrical degradation experiments in the Japan materials testing reactor

    Farnum, E.; Scharborough, K. [Los Alamos National Lab., NM (United States); Shikama, Tatsuo [and others


    The objective of this experiment is to determine the extent of degradation during neutron irradiation of electrical and optical properties of candidate dielectric materials. The goals are to identify promising dielectrics for ITER and other fusion machines for diagnostic applications and establish the basis for optimization of candidate materials. An experiment to measure radiation-induced electrical degradation (REID) in sapphire and MgO-insulated cables was conducted at the JMTR light water reactor. The materials were irradiated at about 260 {degree}C to a fluence of 3{times}10{sup 24} n/m{sup 2} (E>1 MeV) with an applied DC electric field between 100 kV/m and 500 kV/m.

  10. Tame Fusion

    S.D. Scott


    The first section of this paper covers preliminaries. Essentially, the next four cover units. It is shown that a compatible nearring with DCCR is Nnilpotent if and only if every maximal right N-subgroup is a right ideal. The last five sections relate to fusion (I.e., N-groups minimal for being generated by Nsubgroups, where each is N-isomorphic to a given N-group). Right N-subgroups of a tame nearring N with DCCR, minimal for not annihilating a minimal ideal from the left, are self monogenic and N-isomorphic. That this holds for any collection of minimal ideals is significant. Here, the right N-subgroup involved is a 'fusion product' of the 'components'.

  11. High temperature superconductor cable concepts for fusion magnets



    Three concepts of high temperature superconductor cables carrying kA currents (RACC, CORC and TSTC) are investigated, optimized and evaluated in the scope of their applicability as conductor in fusion magnets. The magnetic field and temperature dependence of the cables is measured; the thermal expansion and conductivity of structure, insulation and filling materials are investigated. High temperature superconductor winding packs for fusion magnets are calculated and compared with corresponding low temperature superconductor cases.

  12. Carpal Fusion


    Carpal fusion may be seen in hereditary and nonhereditary conditions such as acrocallosal syndrome,acromegaly, Apert syndrome, arthrogryposis, Carpenter syndrome, chromosomal abnormalities, ectrodactyly-ectodermal dysplasia-cleft (EEC) syndrome, the F form of acropectorovertebral dysgenesis or the F syndrome, fetal alcohol syndrome, Holt-Oram syndrome, Leopard syndrome, multiple synostosis syndrome, oligosyndactyly syndrome, Pfeiffer-like syndrome, scleroderma, split hand and foot malformatio...

  13. Fusion rules of equivariantizations of fusion categories


    We determine the fusion rules of the equivariantization of a fusion category $\\mathcal{C}$ under the action of a finite group $G$ in terms of the fusion rules of $\\mathcal{C}$ and group-theoretical data associated to the group action. As an application we obtain a formula for the fusion rules in an equivariantization of a pointed fusion category in terms of group-theoretical data. This entails a description of the fusion rules in any braided group-theoretical fusion category.

  14. Fusion rules of equivariantizations of fusion categories

    Burciu, Sebastian; Natale, Sonia


    We determine the fusion rules of the equivariantization of a fusion category $\\mathcal{C}$ under the action of a finite group $G$ in terms of the fusion rules of $\\mathcal{C}$ and group-theoretical data associated to the group action. As an application we obtain a formula for the fusion rules in an equivariantization of a pointed fusion category in terms of group-theoretical data. This entails a description of the fusion rules in any braided group-theoretical fusion category.

  15. The Fusion Driven Rocket: Nuclear Propulsion through Direct Conversion of Fusion Energy Project

    National Aeronautics and Space Administration — Current nuclear fusion efforts have focused on the generation of electric grid power and are wholly inappropriate for space transportation as the application of a...

  16. Fusion Energy for Hydrogen Production

    Fillo, J. A.; Powell, J. R.; Steinberg, M.; Salzano, F.; Benenati, R.; Dang, V.; Fogelson, S.; Isaacs, H.; Kouts, H.; Kushner, M.; Lazareth, O.; Majeski, S.; Makowitz, H.; Sheehan, T. V.


    The decreasing availability of fossil fuels emphasizes the need to develop systems which will produce synthetic fuel to substitute for and supplement the natural supply. An important first step in the synthesis of liquid and gaseous fuels is the production of hydrogen. Thermonuclear fusion offers an inexhaustible source of energy for the production of hydrogen from water. Depending on design, electric generation efficiencies of approximately 40 to 60% and hydrogen production efficiencies by high temperature electrolysis of approximately 50 to 70% are projected for fusion reactors using high temperature blankets.

  17. Insulation materials. Cellulose fiber and expanded polystyrene insulations

    Viladot Bel, Cèlia


    The main role of thermal insulation materials in a building envelope are to prevent heat loss and provide thermal comfort for a building's interior. The factor that characterizes an insulation material's effectiveness is its thermal conductivity λ (measured in W/mK). The lower a material's thermal conductivity, the more effective it is as an insulator. Traditional insulation materials include glass fibre, stone wool, expanded polystyrene, and polyurethane foam. While these materials are effic...

  18. Transcription Independent Insulation at TFIIIC-Dependent Insulators

    Valenzuela, Lourdes; Dhillon, Namrita; Kamakaka, Rohinton T.


    Chromatin insulators separate active from repressed chromatin domains. In yeast the RNA pol III transcription machinery bound to tRNA genes function with histone acetylases and chromatin remodelers to restrict the spread of heterochromatin. Our results collectively demonstrate that binding of TFIIIC is necessary for insulation but binding of TFIIIB along with TFIIIC likely improves the probability of complex formation at an insulator. Insulation by this transcription factor occurs in the abse...

  19. Condensation in insulated homes

    Wiley, R A


    A research proposal on condensation in insulated homes is presented. Information is provided on: justification for condensation control; previous work and present outlook (good vapor barrier, condensation and retrofit insulation, vapor barrier decreases condensation, brick-veneer walls, condensation in stress-skin panels, air-conditioned buildings, retrofitting for conservation, study on mobile homes, high indoor relative humidity, report on various homes); and procedure (after funding has been secured). Measures are briefly described on opening walls, testing measures, and retrofitting procedures. An extensive bibliography and additional informative citations are included. (MCW)

  20. Super insulating aerogel glazing

    Schultz, Jørgen Munthe; Jensen, Karsten Ingerslev; Kristiansen, Finn Harken


    Monolithic silica aerogel offers the possibility of combining super insulation and high solar energy transmittance, which has been the background for a previous and a current EU project on research and development of monolithic silica aerogel as transparent insulation in windows. Generally, windows...... form the weakest part of the thermal envelope with respect to heat loss coefficient, but on the other hand also play an important role for passive solar energy utilisation. For window orientations other than south, the net energy balance will be close to or below zero. However, the properties...

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

    Jian Li


    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.

  2. Design and Construction of a Live Insulator Washing System for Transformers

    Lizama-Cámara Y.A.


    Full Text Available Through the electrical industry history there have been developments of different cleaning methods to avoid the insulators flashovers due to pollution. This paper describes the principal cleaning methods applicable to transformers insulators, emphasizing the high pressure fixed-type live insulator washing method, which was applied for cleaning the insulators of 900 MVA transformer bank of the “Laguna Verde” power plant localized at the state of Veracruz in Mexico. We propose a transformer insulator cleaning methodology, which identifies the main variables to take into account (the voltage level of the transformers, the pollution level of the insulators, determination of the optimal wash time, the amount of water, the optimal pressure of water jet, the maximum conductivity of the water and the wind velocity, reference values are given for these variables. In addition, we present an economic cost analysis when applying a method of this kind in an electric substation.

  3. Study on Production Method of Electric Detonator Insulation Plastic Head by Reusing of Waste High-pressure Polyethylene%废高压聚乙烯循环利用生产电雷管绝缘塑头的方法研究

    李树彬; 陈良友


    The production method of electric detonator insulation plastic head by reusing of detonating tube via crushing, digestion, rinse and drying was studied. Through adding liquid additive X in waste high-pressure polyethylene, replacing small discharge duct of injection molding machine, installing micro mixer in the injection molding machine, melting point index of treated plastic reached to 1.85 g / 10 min, tensile strength was12 MPa, melting temperature was 110 ℃, injection temperature was 188 ℃.So the treated plastic can be used to produce safe and reliable electric detonator insulation plastic head.%  研究了废导爆管经粉碎、蒸煮、漂洗、烘干生产电雷管绝缘塑头的方法.采用在废高压聚乙烯中加入液体添加剂X、更换注塑机狭小的下料管、在注塑机上安装微型搅拌机等方法,使废塑料的熔点指数达到1.85 g/10 min,拉伸强度12 MPa,熔化温度110℃,注塑温度188℃,使废塑料安全、可靠的生产电管雷绝缘塑头.

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

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


    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.

  5. Influence of graphene oxide on metal-insulator-semiconductor tunneling diodes

    Lin, Chu-Hsuan; Yeh, Wei-Ting; Chan, Chun-Hui; Lin, Chun-Chieh


    In recent years, graphene studies have increased rapidly. Graphene oxide, which is an intermediate product to form graphene, is insulating, and it should be thermally reduced to be electrically conductive. We herein describe an attempt to make use of the insulating properties of graphene oxide. The graphene oxide layers are deposited onto Si substrates, and a metal-insulator-semiconductor tunneling structure is formed and its optoelectronic properties are studied. The accumulation dark curren...

  6. Hangman 骨折后Zephir 钢板颈前路内固定技术的应变电测研究%Study of electric measure of intervertebral fusion and internal fixation with Hangman fracture

    陈语; 项良碧; 郭明明; 于海龙; 王琪; 兀巍; 祖启明; 刘军


    目的 比较Hangman 骨折后两种不同前路手术方式的生物力学特性.方法 对6 例新鲜尸体Hangman 骨折模型后,依次采用C2-3开槽植骨融合钢板内固定术(C2-3组)和C3椎体大部分切除、植骨内固定术(C2-4组)2 种术式,采用电测法测定其螺钉的拔出应力.结果 C2-3组在屈曲和伸展运动状态下,在不同载荷下所承受的应力均大于C2-4组(P0.05).结论 生理环境下C2-3植骨融合内固定术可能相对容易出现内植物相关并发症.%Objective To compare the biomechanical properties of C2-3 ir.tervertebral fusion and C2-4 anterior fusion in Hangman fracture. Methods The model of Hangman fracture prepared from the six fresh human upper cervical vertebra specimens were fixed as C2-3 group and C2-4 group. Using strain electric measure,pull—out stress of the screws of the two fixations were calculated- Results (n C2-3 group, the stress of flexion and extension under difference loading conditions was greater than that of C2-4 group (P<0.05);although the C2_3 group screws bore the greatest pull—out stress on extension at 2.5Nm ( 12.47+3.23 MpaJ. Although the stress of C2-3 group screws was slightly greater than that of C2-4 group screws on left/right axial rotation,the difference was not statistically significant (P>0.05). Conclusion Complications are more likely to occur in physiological settings when C2_3 intervertebral fusion fixation is used.

  7. Insulated ECG electrodes

    Portnoy, W. M.; David, R. M.


    Insulated, capacitively coupled electrode does not require electrolyte paste for attachment. Other features of electrode include wide range of nontoxic material that may be employed for dielectric because of sputtering technique used. Also, electrode size is reduced because there is no need for external compensating networks with FET operational amplifier.

  8. Transcription independent insulation at TFIIIC-dependent insulators.

    Valenzuela, Lourdes; Dhillon, Namrita; Kamakaka, Rohinton T


    Chromatin insulators separate active from repressed chromatin domains. In yeast the RNA pol III transcription machinery bound to tRNA genes function with histone acetylases and chromatin remodelers to restrict the spread of heterochromatin. Our results collectively demonstrate that binding of TFIIIC is necessary for insulation but binding of TFIIIB along with TFIIIC likely improves the probability of complex formation at an insulator. Insulation by this transcription factor occurs in the absence of RNA polymerase III or polymerase II but requires specific histone acetylases and chromatin remodelers. This analysis identifies a minimal set of factors required for insulation.


    Caroline; 黄颖(翻译)


    Fusion World”科技展示体验中心是英国设计公司MET Studio为新加坡科技研究局(A*Star)的科学工程委员会(SERC)所设计的,位于启汇城的办公地点,用于展示该委员会的精选技术作品,以吸引潜在的客户和启汇城内的学生购买群体。

  10. Trends of the technology for gas insulated switchgear

    Sasaki, Koji; Daimon, Goro; Yamagiwa, Tokio; Endo, Fumihiro


    This is the introduction of the recent technology for gas insulated switchgears. Analysis, detection, and survey technologies from the development stage to the operation stage have made progresses. The third dimension analysis technology makes it possible to make high resolution analysis of asymmetric parts, and the analysis of insulating gas heat flow at the time of high electric current flow. Partial discharge of electricity and supersonic waves have made possible the highly sensitive detection of conductive debris to secure the SF/sub 6/ gas insulation. Lightning surge observation system has been developed and is reflected in the coordination of insulation technology. Application of these technologies to predicative maintenance is also studied. An air shelter was developed to prevent the invasion of debris at the time of assembling on the spot, and for the last examination an impulse testing device is used to confirm the insulation. So far 8,000 gas circuit breakers have been supplied; the coltage was heightened to 550kV and the capacity was augmented to 63kA; and the breaking efficiency leaped high thanks to the improvement of arc extinguish chambers and to the development of new insulating material. Noise was abated, and the breaking capacity per one point has been augmented, so the number of breaking points has been abated. Miniaturization of the switchgear has been materialized by the completion of the all three phase package type. (17 figs, 6 refs)

  11. Anomalous photoelectric effect of a polycrystalline topological insulator film.

    Zhang, Hongbin; Yao, Jiandong; Shao, Jianmei; Li, Hai; Li, Shuwei; Bao, Dinghua; Wang, Chengxin; Yang, Guowei


    A topological insulator represents a new state of quantum matter that possesses an insulating bulk band gap as well as a spin-momentum-locked Dirac cone on the surface that is protected by time-reversal symmetry. Photon-dressed surface states and light-induced surface photocurrents have been observed in topological insulators. Here, we report experimental observations of an anomalous photoelectric effect in thin films of Bi2Te3, a polycrystalline topological insulator. Under illumination with non-polarised light, transport measurements reveal that the resistance of the topological surface states suddenly increases when the polycrystalline film is illuminated. The resistance variation is positively dependent on the light intensity but has no relation to the applied electric field; this finding can be attributed to the gap opening of the surface Dirac cone. This observation of an anomalous photoelectric effect in polycrystalline topological insulators offers exciting opportunities for the creation of photodetectors with an unusually broad spectral range. Moreover, polycrystalline topological insulator films provide an attractive material platform for exploring the nature and practical application of topological insulators.

  12. Polyimide/Glass Composite High-Temperature Insulation

    Pater, Ruth H.; Vasquez, Peter; Chatlin, Richard L.; Smith, Donald L.; Skalski, Thomas J.; Johnson, Gary S.; Chu, Sang-Hyon


    Lightweight composites of RP46 polyimide and glass fibers have been found to be useful as extraordinarily fire-resistant electrical-insulation materials. RP46 is a polyimide of the polymerization of monomeric reactants (PMR) type, developed by NASA Langley Research Center. RP46 has properties that make it attractive for use in electrical insulation at high temperatures. These properties include high-temperature resistance, low relative permittivity, low dissipation factor, outstanding mechanical properties, and excellent resistance to moisture and chemicals. Moreover, RP46 contains no halogen or other toxic materials and when burned it does not produce toxic fume or gaseous materials. The U. S. Navy has been seeking lightweight, high-temperature-resistant electrical-insulation materials in a program directed toward reducing fire hazards and weights in ship electrical systems. To satisfy the requirements of this program, an electrical-insulation material must withstand a 3-hour gas-flame test at 1,600 F (about 871 C). Prior to the development reported here, RP46 was rated for use at temperatures from -150 to +700 F (about -101 to 371 C), and no polymeric product - not even RP46 - was expected to withstand the Navy 3-hour gas-flame test.

  13. Carpal Fusion

    Jalal Jalalshokouhi*


    Full Text Available Carpal fusion may be seen in hereditary and nonhereditary conditions such as acrocallosal syndrome,acromegaly, Apert syndrome, arthrogryposis, Carpenter syndrome, chromosomal abnormalities, ectrodactyly-ectodermal dysplasia-cleft (EEC syndrome, the F form of acropectorovertebral dysgenesis or the F syndrome, fetal alcohol syndrome, Holt-Oram syndrome, Leopard syndrome, multiple synostosis syndrome, oligosyndactyly syndrome, Pfeiffer-like syndrome, scleroderma, split hand and foot malformation, Stickler syndrome, thalidomide embryopathy, Turner syndrome and many other conditions as mentioned in Rubinstein-Taybi's book. Sometimes there is no known causative disease.Diagnosis is usually made by plain X-ray during studying a syndrome or congenital disease or could be an incidental finding like our patients. Hand bone anomalies are more common in syndromes or other congenital or non-hereditary conditions, but polydactyly, syndactyly or oligodactyly and carpal fusions are interesting. X-ray is the modality of choice, but MRI and X-ray CT with multiplanar reconstructions may be used for diagnosis.

  14. Insulation Characteristics of Bushing Shed at Cryogenic Temperature

    Kim, W. J.; Kim, Y. J.; Kim, S. H.


    In the development of high-Tc superconducting(HTS) devices, the bushing for HTS devices (HTS bushing) is the core technology, the need to because of supply high voltage to the cable or the winding of the transformer. The lower part of the bushing is exposed to the liquid nitrogen (LN2), and it has many sheds. In particular, the insulation body with sheds and electrical insulation at cryogenic temperature have attracted a great deal of interest from the view point of the size, weight and efficiency of bushing. This study has mainly investigated the shed and insulation body by comparing glass fiber reinforced plastics (GFRP) in LN2. We investigated the surface discharge characteristics according to insulating materials, width and height of the shed.

  15. Using fiberglass volumes for VPI of superconductive magnetic systems’ insulation

    Andreev, I. S.; Bezrukov, A. A.; Pischugin, A. B. [Sredne-Nevskiy Shipyard (SNSZ), 10 Zavodskaya str., c. Pontonniy, Saint-Petersburg (Russian Federation); Bursikov, A. S.; Klimchenko, Y. A.; Marushin, E. L.; Mednikov, A. A.; Rodin, I. Y.; Stepanov, D. B. [The D.V. Efremov Scientific Research Institute of Electrophysical Apparatus (NIIEFA), 3 Doroga na Metallostroy, Metallostroy, Saint-Petersburg (Russian Federation)


    The paper describes the method of manufacturing fiberglass molds for vacuum pressure impregnation (VPI) of high-voltage insulation of superconductive magnetic systems (SMS) with epoxidian hot-setting compounds. The basic advantages of using such vacuum volumes are improved quality of insulation impregnation in complex-shaped areas, and considerable cost-saving of preparing VPI of large-sized components due to dispensing with the stage of fabricating a metal impregnating volume. Such fiberglass vacuum molds were used for VPI of high-voltage insulation samples of an ITER reactor’s PF1 poloidal coil. Electric insulation of these samples has successfully undergone a wide range of high-voltage and mechanical tests at room and cryogenic temperatures. Some results of the tests are also given in this paper.

  16. Topological insulator-based energy efficient devices

    Chen, Yong P.


    Topological insulators (TI) have emerged as a new class of quantum materials with many novel and unusual properties. In this article, we will give a brief review of the key electronic properties of topological insulators, including the signatures for the unusual electronic transport properties of their characteristic topological surface states (TSS). We will then discuss how these novel properties and physics may be utilized for TI-based energy efficient devices, such as lowpower- consumption electronics and high performance thermo-electrics. Furthermore, going beyond conventional singleparticle, charge-based transport, to utilize coherent many-body coherent ground states such as excitonic condensates (EC), new and intriguing functionalities previously unexplored in electronic and energy devices may be realized with the potential to dramatically improve the energy efficiency.

  17. 30 CFR 56.12004 - Electrical conductors.


    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Electrical conductors. 56.12004 Section 56....12004 Electrical conductors. Electrical conductors shall be of a sufficient size and current-carrying... insulating materials. Electrical conductors exposed to mechanical damage shall be protected....

  18. 30 CFR 57.12004 - Electrical conductors.


    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Electrical conductors. 57.12004 Section 57... Surface and Underground § 57.12004 Electrical conductors. Electrical conductors shall be of a sufficient... operations will not damage the insulating materials. Electrical conductors exposed to mechanical damage...

  19. 30 CFR 77.1914 - Electrical equipment.


    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Electrical equipment. 77.1914 Section 77.1914... Shaft Sinking § 77.1914 Electrical equipment. (a) Electric equipment employed below the collar of a.... (b) The insulation of all electric conductors employed below the collar of any slope or shaft...

  20. Industrial thermal insulation: an assessment

    Donnelly, R.G.; Tennery, V.J.; McElroy, D.L.; Godfrey, T.G.; Kolb, J.O.


    A large variety of thermal insulation materials is manufactured for application in various temperature ranges and environments. Additional and improved thermal insulation for steam systems is a key area with immediate energy conservation potential in several of the larger energy-consuming industries. Industrial thermal insulation technology was assessed by obtaining input from a variety of sources including insulation manufacturers, system designers, installers, users, consultants, measurement laboratories, open literature, and in-house knowledge. The assessment identified a number of factors relevant to insulation materials and usage that could contribute significantly to improved energy conservation.

  1. Organic thin film transistors with a SiO2/SiNx/SiO2 composite insulator layer

    Liu Xiang; Liu Hui


    We have investigated a SiO2/SiNx/SiO2 composite insulation layer structured gate dielectric for an organic thin film transistor (OTFT) with the purpose of improving the performance of the SiO2 gate insulator.The SiO2/SiNx/SiO2 composite insulation layer was prepared by magnetron sputtering.Compared with the same thickness of a SiO2 insulation layer device,the SiO2/SiNx/SiO2 composite insulation layer is an effective method of fabricating OTFT with improved electric characteristics and decreased leakage current.Electrical parameters such as carrier mobility by field effect measurement have been calculated.The performances of different insulating layer devices have been studied,and the results demonstrate that when the insulation layer thickness increases,the off-state current decreases.

  2. Electrically floating, near vertical incidence, skywave antenna

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


    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.

  3. Designing and Implementation a Lab Testing Method for Power Cables Insulation Resistance According with STAS 10411-89, SR EN ISO/CEI/17025/2005

    Dobra, R.; Pasculescu, D.; Marc, G.; Risteiu, M.; Antonov, A.


    Insulation resistance measurement is one of the most important tests required by standards and regulations in terms of electrical safety. Why these tests are is to prevent possible accidents caused by electric shock, damage to equipment or outbreak of fire in normal operating conditions of electrical cables. The insulation resistance experiment refers to the testing of electrical cable insulation, which has a measured resistance that must be below the imposed regulations. Using a microcontroller system data regarding the insulation resistance of the power cables is acquired and with SCADA software the test results are displayed.

  4. Heavy ion fusion experiments at LBNL and LLNL

    Ahle, L


    The long-range goal of the US Heavy Ion Fusion (HIF) program is to develop heavy ion accelerators capable of igniting inertial fusion targets to generate fusion energy for electrical power production. Accelerators for heavy ion fusion consist of several subsystems: ion sources, injectors, matching sections, combiners, induction acceleration sections with electric and magnetic focusing, beam compression and bending sections, and a final-focus system to focus the beams onto the target. We are currently assembling or performing experiments to address the physics of all these subsystems. This paper will discuss some of these experiments.

  5. Catalysed fusion

    Farley, Francis


    A sizzling romance and a romp with subatomic particles at CERN. Love, discovery and adventure in the city where nations meet and beams collide. Life in a large laboratory. As always, the challenges are the same. Who leads? Who follows? Who succeeds? Who gets the credit? Who gets the women or the men? Young Jeremy arrives in CERN and joins the quest for green energy. Coping with baffling jargon and manifold dangers, he is distracted by radioactive rats, lovely ladies and an unscrupulous rival. Full of doubts and hesitations, he falls for a dazzling Danish girl, who leads him astray. His brilliant idea leads to a discovery and a new route to cold fusion. But his personal life is scrambled. Does it bring fame or failure? Tragedy or triumph?

  6. Super insulating aerogel glazing

    Schultz, Jørgen Munthe; Jensen, Karsten Ingerslev; Kristiansen, Finn Harken


    Monolithic silica aerogel offers the possibility of combining super insulation and high solar energy transmittance, which has been the background for a previous and a current EU project on research and development of monolithic silica aerogel as transparent insulation in windows. Generally, windows...... form the weakest part of the thermal envelope with respect to heat loss coefficient, but on the other hand also play an important role for passive solar energy utilisation. For window orientations other than south, the net energy balance will be close to or below zero. However, the properties...... of aerogel glazing will allow for a positive net energy gain even for north facing vertical windows in a Danish climate during the heating season. This means that high quality daylight can be obtained even with additional energy gain. On behalf of the partners of the two EU projects, results related...

  7. Green insulation: hemp fibers



    Indian hemp (Cannabis indica) is known for its psychotropic values and it is banned in most countries. However, industrial hemp (Cannabis sativa) is known for its tough fibers. Several manufactures in Europe including, small niche players, have been marketing hemp insulation products for several years. Hemp is a low environmental impact material. Neither herbicide nor pesticide is used during the growth of hemp. The fibers are extracted in a waste-free and chemical-free mechanical process. Hemp can consume CO2 during its growth. In addition, hemp fiber can be disposed of harmlessly by composting or incineration at the end of its life. Hemp fibers are processed and treated only minimally to resist rot and fungal activity. There is little health risk when producing and installing the insulation, thanks to the absence of toxic additive. Its thermal resistance is comparable to mineral wool. But the development and marketing of hemp fibers may be restricted in North America.

  8. Photonic Floquet Topological Insulators

    Rechtsman, Mikael C; Plotnik, Yonatan; Lumer, Yaakov; Nolte, Stefan; Segev, Mordechai; Szameit, Alexander


    The topological insulator is a fundamentally new phase of matter, with the striking property that the conduction of electrons occurs only on its surface, not within the bulk, and that conduction is topologically protected. Topological protection, the total lack of scattering of electron waves by disorder, is perhaps the most fascinating and technologically important aspect of this material: it provides robustness that is otherwise known only for superconductors. However, unlike superconductivity and the quantum Hall effect, which necessitate low temperatures or magnetic fields, the immunity to disorder of topological insulators occurs at room temperature and without any external magnetic field. For this reason, topological protection is predicted to have wide-ranging applications in fault-tolerant quantum computing and spintronics. Recently, a large theoretical effort has been directed towards bringing the concept into the domain of photonics: achieving topological protection of light at optical frequencies. ...

  9. 30 CFR 56.12010 - Isolation or insulation of communication conductors.


    ... conductors. 56.12010 Section 56.12010 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF... MINES Electricity § 56.12010 Isolation or insulation of communication conductors. Telephone and low... energized power conductors or any other power source....

  10. Multi-unit inertial fusion plants based on HYLIFE-II, with shared heavy-ion RIA driver and target factory, producing electricity and hydrogen fuel

    Logan, G.; Moir, R. [Lawrence Livermore National Lab., CA (United States); Hoffman, M. [Univ. of California, Davis, CA (United States)


    Following is a modification of the IFEFUEL systems code, called IFEFUEL2, to treat specifically the HYLIFE-II target chamber concept. The same improved Recirculating Induction Accelerator (RIA) energy scaling model developed recently by Bieri is used in this survey of the economics of multi-unit IFE plants producing both electricity and hydrogen fuel. Reference cases will assume conventional HI-indirect target gains for a 2 mm spot, and improved HYLIFE-II BoP models as per Hoffman. Credits for improved plant availability and lower operating costs due to HYLIFE-II`s 30-yr target chamber lifetime are included, as well as unit cost reductions suggested by Delene to credit greater {open_quotes}learning curve{close_quotes} benefits for the duplicated portions of a multi-unit plant. To illustrate the potential impact of more advanced assumptions, additional {open_quotes}advanced{close_quotes} cases will consider the possible benefits of an MHD + Steam BoP, where direct MHD conversion of plasma from baseball-size LiH target blanket shells is assumed to be possible in a new (as yet undesigned) liquid Flibe-walled target chamber, together and separately, with advanced, higher-gain heavy-ion targets with Fast Ignitors. These runs may help decide the course of a possible future {open_quotes}HYLIFE-III{close_quotes} IFE study. Beam switchyard and final focusing system costs per target chamber are assumed to be consistent with single-sided illumination, for either {open_quotes}conventional{close_quotes} or {open_quotes}advanced{close_quotes} indirect target gain assumptions. Target costs are scaled according to the model by Woodworth. In all cases, the driver energy and rep rate for each chosen number of target chambers and total plant output will be optimized to minimize the cost of electricity (CoE) and the associated cost of hydrogen (CoH), using a relationship between CoE and CoH to be presented in the next section.

  11. An electrostatic deflector for a fusion reaction

    ZHANG Huan-Qiao; LIN Cheng-Jian; YANG Feng; JIA Hui-Ming; ZHOU Ping; AN Guang-Peng; ZHANG Chun-Lei; XU Xin-Xing


    An electrostatic deflector for separating the fusion evaporation residues from the beam-like products in heavy ion reactions was installed.The evaporation residue separation and identification with the electrostatic deflector setup was tested with the reaction 32S+96Zr at several energies.The fusion evaporation residues and the beam-like particles were well separated after the electrical separation and the experimental fusion cross section obtained from the angular distribution is in good agreement with the calculated value well above the Coulomb barrier.This confirms the reliability of the setup.

  12. Direct conversion of fusion energy

    Johansson, Markus


    Deuterium and tritium are expected to be used as fuel in the first fusion reactors. Energy is released as kinetic energy of ions and neutrons, when deuterium reacts with tritium. One way to convert the kinetic energy to electrical energy, is to let the ions and neutrons hit the reactor wall and convert the heat that is caused by the particle bombardment to electrical energy with ordinary thermal conversion. If the kinetic energy of the ions instead is converted directly to electrical energy, a higher efficiency of the energy conversion is possible. The majority of the fusion energy is released as kinetic energy of neutrons, when deuterium reacts with tritium. Fusion reactions such as the D-D reactions, the D-{sup 3}He reaction and the p-{sup 11}B reaction, where a larger part of the fusion energy becomes kinetic energy of charged particles, appears therefore more suitable for direct conversion. Since they have lower reactivity than the D-T reaction, they need a larger {beta}B{sup 2}{sub 0} to give sufficiently high fusion power density. Because of this, the fusion configurations spherical torus (ST) and field-reversed configuration (FRC), where high {beta} values are possible, appear interesting. Rosenbluth and Hinton come to the conclusion that efficient direct conversion isn't possible in closed field line systems and that open geometries, which facilitate direct conversion, provide inadequate confinement for D-{sup 3}He. It is confirmed in this study that it doesn't seem possible to achieve as high direct conversion efficiency in closed systems as in open systems. ST and FRC fusion power plants that utilize direct conversion seem however interesting. Calculations with the help of Maple indicate that the reactor parameters needed for a D-D ST and a D{sub 3} He ST hopefully are possible to achieve. The best energy conversion option for a D-D or D{sub 3} He ST appears to be direct electrodynamic conversion (DEC) together with ordinary thermal conversion

  13. Chemical oxidation of cable insulating oil contaminated soil

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


    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 oxidati

  14. Microwave photonic phase shifter based on tunable silicon-on-insulator microring resonator

    Pu, Minhao; Liu, Liu; Xue, Weiqi;


    We demonstrate a microwave photonic phase shifter based on an electrically tunable silicon-on-insulator microring resonator. A continuously tunable phase shift of up to 315° at a microwave frequency of 15GHz is obtained.......We demonstrate a microwave photonic phase shifter based on an electrically tunable silicon-on-insulator microring resonator. A continuously tunable phase shift of up to 315° at a microwave frequency of 15GHz is obtained....

  15. Antifuse with a single silicon-rich silicon nitride insulating layer

    Habermehl, Scott D.; Apodaca, Roger T.


    An antifuse is disclosed which has an electrically-insulating region sandwiched between two electrodes. The electrically-insulating region has a single layer of a non-hydrogenated silicon-rich (i.e. non-stoichiometric) silicon nitride SiN.sub.X with a nitrogen content X which is generally in the range of 0silicon. Arrays of antifuses can also be formed.

  16. Holographic Metals and Insulators with Helical Symmetry

    Donos, Aristomenis; Kiritsis, Elias


    Homogeneous, zero temperature scaling solutions with Bianchi VII spatial geometry are constructed in Einstein-Maxwell-Dilaton theory. They correspond to quantum critical saddle points with helical symmetry at finite density. Assuming $AdS_{5}$ UV asymptotics, the small frequency/(temperature) dependence of the AC/(DC) electric conductivity along the director of the helix are computed. A large class of insulating and conducting anisotropic phases is found, as well as isotropic, metallic phases. Conduction can be dominated by dissipation due to weak breaking of translation symmetry or by a quantum critical current.

  17. Heat transfer through cable insulation of Nb-Ti superconducting magnets operating in He II

    Granieri, P. P.


    The operation of Nb-Ti superconducting magnets in He II relies on superfluidity to overcome the severe thermal barrier represented by the cable electrical insulation. In wrapped cable insulations, like those used for the main magnets of the Large Hadron Collider (LHC) particle accelerator, the micro-channels network created by the insulation wrappings allows to efficiently transfer the heat deposited or generated in the cable to the He bath. In this paper, available experimental data of heat transfer through polyimide electrical insulation schemes are analyzed. A steady-state thermal model is developed to describe the insulation of the LHC main dipole magnets and the Enhanced Insulation proposed for the High Luminosity LHC upgrade (HL-LHC), according to the relevant geometric parameters. The model is based on the coupled mechanisms of heat transfer through the bulk of the dielectric insulation and through micro-channels between the insulation tapes. A good agreement is found between calculations and tests performed at different applied pressures and heating configurations. The model allows identifying the heat fluxes in the cable cross-section as well as the dimensions of the micro-channels. These dimensions are confirmed by microscope images of the two insulations schemes.

  18. Semi-flexible gas-insulated transmission line using sandwiched discs for intermittent flexing joints

    Kommineni, Prasad R. (Westboro, MA)


    A gas-insulated transmission line includes an outer sheath, an inner conductor, an insulating gas electrically insulating the inner conductor from the outer sheath, and insulating supports insulatably supporting the inner conductor within the outer sheath. The inner conductor is provided with flexibility by the use of main conductor sections which are joined together through a conductor hub section and flexible flexing elements. Stress shields are provided to control the electric field at the locations of the conductor hub sections where the insulating supports are contacting the inner conductor. The flexing elements are formed by sandwiching together, by fusing, a pair of thin hollow discs which are fixedly secured to both the main conductor sections and the conductor hub section.

  19. Semi-flexible gas-insulated transmission line using sandwiched discs for intermittent flexing joints

    Kommineni, P.R.


    A gas-insulated transmission line includes an outer sheath, an inner conductor, an insulating gas electrically insulating the inner conductor from the outer sheath, and insulating supports insulatably supporting the inner conductor within the outer sheath. The inner conductor is provided with flexibility by the use of main conductor sections which are joined together through a conductor hub section and flexible flexing elements. Stress shields are provided to control the electric field at the locations of the conductor hub sections where the insulating supports are contacting the inner conductor. The flexing elements are formed by sandwiching together, by fusing, a pair of thin hollow discs which are fixedly secured to both the main conductor sections and the conductor hub section. 4 figs.

  20. Low-temperature thermal properties from the EU testing program for potential ITER insulation

    Broadbent, A.J.; Crozier, J.; Smith, K.D. [Oxford Instruments Special Projects, Oxon (United Kingdom)] [and others


    Insulation systems will be a key element in the future construction and impregnation of the coils for the ITER device. The thermal contraction and thermal conductivity of ten different electrical insulation systems are measured at temperatures from 4 K to 300 K. Several insulation systems incorporate an electrical barrier layer. The insulation systems are all based on identical S2-glass with various epoxy resins, some of which are not believed to have been previously used in superconducting coils. In particular resins with a high functionality are investigated, some of which are suitable for Vacuum Pressure Impregnation (VPI). The final results of this program are presented and compared to the results from a benchmark testing program (insulation system based on anhydride cured DGEBA resin and S2 glass). This work is financed by the EU under NET contract ERB 5000 940023 (NET 93-857) within the framework of MR.

  1. Spintronics Based on Topological Insulators

    Fan, Yabin; Wang, Kang L.


    Spintronics using topological insulators (TIs) as strong spin-orbit coupling (SOC) materials have emerged and shown rapid progress in the past few years. Different from traditional heavy metals, TIs exhibit very strong SOC and nontrivial topological surface states that originate in the bulk band topology order, which can provide very efficient means to manipulate adjacent magnetic materials when passing a charge current through them. In this paper, we review the recent progress in the TI-based magnetic spintronics research field. In particular, we focus on the spin-orbit torque (SOT)-induced magnetization switching in the magnetic TI structures, spin-torque ferromagnetic resonance (ST-FMR) measurements in the TI/ferromagnet structures, spin pumping and spin injection effects in the TI/magnet structures, as well as the electrical detection of the surface spin-polarized current in TIs. Finally, we discuss the challenges and opportunities in the TI-based spintronics field and its potential applications in ultralow power dissipation spintronic memory and logic devices.

  2. Condition assessment of transformer insulation using dielectric frequency response analysis by artificial bee colony algorithm

    Bigdeli Mehdi


    Full Text Available Transformers are one of the most important components of the power system. It is important to maintain and assess the condition. Transformer lifetime depends on the life of its insulation and insulation life is also strongly influenced by moisture in the insulation. Due to importance of this issue, in this paper a new method is introduced for determining the moisture content of the transformer insulation system using dielectric response analysis in the frequency domain based on artificial bee colony algorithm. First, the master curve of dielectric response is modeled. Then, using proposed method the master curve and the measured dielectric response curves are compared. By analyzing the results of the comparison, the moisture content of paper insulation, electrical conductivity of the insulating oil and dielectric model dimensions are determined. Finally, the proposed method is applied to several practical samples to demonstrate its capabilities compared with the well-known conventional method.

  3. High Gradient Multilayer Insulator Technology

    Sampayan, S E; Caporaso, G J; Nunnally, W C; Sanders, D M; Watson, J A; Krogh, M L; Anderson, H U


    We are investigating a novel insulator concept that involves the use of alternating layers of conductors and insulators with periods less than 1 mm. These structures perform 1.5 to 4 times better than conventional insulators in long pulse, short pulse, and alternating polarity applications. We survey our ongoing studies investigating the performance under long pulse electron beam, short pulse, and full reversing conditions.

  4. Transport Experiments on Topological Insulators


    UU UU UU 16-08-2016 15-Sep-2011 14-Oct-2014 Final Report: Transport Experiments on Topological Insulators The views, opinions and/or findings contained...Triangle Park, NC 27709-2211 Topological Insulators, Dirac Semimetals, Transport in magnetic field, High mobility REPORT DOCUMENTATION PAGE 11. SPONSOR...ABSTRACT Final Report: Transport Experiments on Topological Insulators Report Title The ARO-supported research focused on uncovering novel materials and

  5. Manifold Insulation for Solar Collectors


    Results of computer analysis of effects of various manifold insulation detailed in 23-page report show that if fluid is distributed to and gathered from array of solar collectors by external rather than internal manifold, effectiveness of manifold insulation has major influence on efficiency. Report describes required input data and presents equations that govern computer model. Provides graphs comparing collector efficiencies for representative manifold sizes and insulations.

  6. Influence of the barite tenors of the Jaicos, Piaui, Brazil, clays on the ceramic properties of electric insulator porcelains; Influencia dos teores de barita das argilas de Jaicos, Piaui, Brasil nas propriedades ceramicas de porcelana de isoladores eletricos

    Correa, W.L.P. [Escola SENAI Mario Amato, Sao Bernardo do Campo, SP (Brazil); Lima, M.B. [Faculdade Sao Bernardo, SP (Brazil); Carvalho, F.M.S. [Universidade de Sao Paulo (USP), SP (Brazil). Inst. de Geociencias


    The clays of the Municipality of Jaicos, Piaui, has been used as raw materials for the manufacture of insulators for company located in the municipality of Pedreira - Sao Paulo. It can be noticed in the clay blocks and consolidated, 'lenses' of barite. The mineralogical composition of clay and the nature of these 'lenses' were studied by chemical analysis, X-ray diffraction for mineralogical characterization. The clays are composed primarily by kaolinite, quartz, and some amount of illite and orthoclase. The presence of orthoclase does believe in a recent deposition of these clays. The 'lenses' were characterized as barite, BaSO{sub 4}. To check the influence of barite in the composition of bodies of porcelain to insulators made up six compositions with different levels of barite, obtained their own clay. It applies, then the tests of ceramic fracture to bending, water absorption, apparent porosity to determine the effect of the introduction of barite in the compositions. (author)

  7. Antiferroelectric Topological Insulators in Orthorhombic A MgBi Compounds (A =Li , Na, K)

    Monserrat, Bartomeu; Bennett, Joseph W.; Rabe, Karin M.; Vanderbilt, David


    We introduce antiferroelectric topological insulators as a new class of functional materials in which an electric field can be used to control topological order and induce topological phase transitions. Using first principles methods, we predict that several alkali-MgBi orthorhombic members of an A B C family of compounds are antiferroelectric topological insulators. We also show that epitaxial strain and hydrostatic pressure can be used to tune the topological order and the band gap of these A B C compounds. Antiferroelectric topological insulators could enable precise control of topology using electric fields, enhancing the applicability of topological materials in electronics and spintronics.

  8. The CRRES IDM spacecraft experiment for insulator discharge pulses. [Internal Discharge Monitor

    Frederickson, A. R.; Mullen, E. G.; Kerns, K. J.; Robinson, P. A.; Holeman, E. G.


    The Internal Discharge Monitor (IDM) is designed to observe electrical pulses from common electrical insulators in space service. The characteristics of the instrument are described. The IDM was flown on the Combined Release and Radiation Effects Satellite (CRRES). The sixteen insulator samples included G10 circuit boards, FR4 and PTFE fiberglass circuit boards, FEP Teflon, alumina, and wires with common insulations. The samples are fully enclosed, mutually isolated, and space radiation penetrates 0.02 cm of aluminum before striking the samples. Published data in the literature provides a simple method for determining the flux of penetrating electrons. The pulse rate is compared to the penetrating flux of electrons.

  9. Thermionic Technology Program: A, Insulator test and evaluation: Final report

    Dobson, J.C.; Witt, T.


    The Thermionic Technology Program (TTP) consisted of two major efforts, evaluation of insulators and evaluation of thermionic converters. This report details the work performed on the insulator phase of the program. Efforts were made to better understand the mechanisms involved in the electrochemistry of insulators at elevated temperatures by modelling the ionic transport through the various layers of the insulator package. Although rigorous analytic solutions could not be obtained owing to a lack of detailed data, a simplified model indicated that alumina should not fail by depletion of aluminum for thousands of years, whereas calculations for yttria revealed a far more rapid depletion of oxygen and consequently earlier failure. Methods for microscopic and electrical testing of cylindrical insulator samples were developed, and an improved test oven design was initiated. Testing of alumina/niobium cermet samples revealed rapid failure contrary to the theoretical predictions for alumina. Large discrepancies in the initial conduction activation energy among the various samples suggested that different mechanisms could have controlled the conduction and hence the failure in different samples, although all had undergone nominally identical processing. The short lifetimes reveal how rapidly ambient conditions in thermionic power conversion can degrade the performance of insulating oxides. It was concluded that minor dopants could have been responsible for the early breakdowns. Thus, high purity materials with precise quality control will be necessary for trilayer package development. 35 refs., 28 figs., 5 tabs.

  10. Developing Process of Negative Creeping Discharge along Aerial Insulated Wire

    Nishi, Toshiyuki; Hanaoka, Ryoichi; Takata, Shinzo

    When a lightning occurs at the neighborhood of high voltage aerial distribution lines, the overvoltage due to the inductive lightning surge invades to the central line of the insulated wire. Because of the insulated wire is supported by the insulator and the binding wire at the electric light pole, the creeping discharges develop along the wire surface from the free end of the binding wire, just after a flashover of the insulator at the wire supporting point. These creeping discharges give rise to the disaster near the wire supporting point including the punch-through breakdown of wire when the weak points such as pin-holes exist in the wire insulator. To prevent these accidents, it is important to understand the behavior of creeping discharges at the insulated wire surface originating in the lightning strike. Positive and negative creeping discharges reveal the distinctive aspect by the polarities of the inductive lightning surges. In the previous paper, we have clarified the developing process of positive creeping discharge based on the data obtained from an image converter camera. In this paper, we report the developing process of negative creeping discharge. Complicated behavior of negative creeping discharge is clarified using an image converter camera and its process is discussed.

  11. Low Permeability Polyimide Insulation Project

    National Aeronautics and Space Administration — Resodyn Technologies proposes a new technology that enables the application of polyimide based cryogenic insulation with low hydrogen permeability. This effort...

  12. Super insulating aerogel glazing

    Schultz, Jørgen Munthe; Jensen, Karsten Ingerslev; Kristiansen, Finn Harken


    This paper describes the application results of a previous and current EU-project on super insulating glazing based on monolithic silica aerogel. Prototypes measuring approx. 55´55 cm2 have been made with 15 mm evacuated aerogel between two layers of low-iron glass. Anti-reflective treatment...... of the glass and a heat-treatment of the aerogel increases the visible quality and the solar energy transmittance. A low-conductive rim seal solution with the required vacuum barrier properties has been developed along with a reliable assembly and evacuation process. The prototypes have a centre heat loss...

  13. Role of Fusion in the Future Energy Market with CO{sub 2} constraints. SERF 4 Socio-Economic Research on Fusion.

    Lechon, Y.; Cabal, H.; Caldes, N.; Varela, M.; Lago, C.; Saez, R.


    Electricity supply technologies considered in global long term technology scenarios. Technological and economic parameters. Calculation of the cost of electricity of the different technologies. Role of fusion in future climate change mitigation scenarios.

  14. Direct Fusion Drive for a Human Mars Orbital Mission

    Paluszek, Michael [Princeton Satellite Systems; Pajer, Gary [Princeton Satellite Systems; Razin, Yosef [Princeton Satellite Systems; Slonaker, James [Princeton Satellite Systems; Cohen, Samuel [PPPL; Feder, Russ [PPPL; Griffin, Kevin [Princeton University; Walsh, Matthew [Princeton University


    The Direct Fusion Drive (DFD) is a nuclear fusion engine that produces both thrust and electric power. It employs a field reversed configuration with an odd-parity rotating magnetic field heating system to heat the plasma to fusion temperatures. The engine uses deuterium and helium-3 as fuel and additional deuterium that is heated in the scrape-off layer for thrust augmentation. In this way variable exhaust velocity and thrust is obtained.

  15. Accelerators for Fusion Materials Testing

    Knaster, Juan; Okumura, Yoshikazu

    Fusion materials research is a worldwide endeavor as old as the parallel one working toward the long term stable confinement of ignited plasma. In a fusion reactor, the preservation of the required minimum thermomechanical properties of the in-vessel components exposed to the severe irradiation and heat flux conditions is an indispensable factor for safe operation; it is also an essential goal for the economic viability of fusion. Energy from fusion power will be extracted from the 14 MeV neutron freed as a product of the deuterium-tritium fusion reactions; thus, this kinetic energy must be absorbed and efficiently evacuated and electricity eventually generated by the conventional methods of a thermal power plant. Worldwide technological efforts to understand the degradation of materials exposed to 14 MeV neutron fluxes >1018 m-2s-1, as expected in future fusion power plants, have been intense over the last four decades. Existing neutron sources can reach suitable dpa (“displacement-per-atom”, the figure of merit to assess materials degradation from being exposed to neutron irradiation), but the differences in the neutron spectrum of fission reactors and spallation sources do not allow one to unravel the physics and to anticipate the degradation of materials exposed to fusion neutrons. Fusion irradiation conditions can be achieved through Li (d, xn) nuclear reactions with suitable deuteron beam current and energy, and an adequate flowing lithium screen. This idea triggered in the late 1970s at Los Alamos National Laboratory (LANL) a campaign working toward the feasibility of continuous wave (CW) high current linacs framed by the Fusion Materials Irradiation Test (FMIT) project. These efforts continued with the Low Energy Demonstrating Accelerator (LEDA) (a validating prototype of the canceled Accelerator Production of Tritium (APT) project), which was proposed in 2002 to the fusion community as a 6.7MeV, 100mA CW beam injector for a Li (d, xn) source to bridge

  16. The influence of insulation materials on corrosion under insulation

    Williams, J.; Evans, O. [Aspen Aerogels Inc., Northborough, MA (United States)


    This paper discussed the ways in which insulation materials influence corrosion under insulation (CUI) behaviour. Laboratory and field tests of 7 industrial insulation materials and 1 composite system were conducted to identify metrics for improving insulation system designs and determine insulation degradation mechanisms. The tested materials included calcium silicate; expanded perlite; cellular glass; mineral wool; and 2 types of aerogel blanket material. Twelve-week accelerated corrosion tests were conducted to gauge the level of corrosion that occurred beneath the materials on uncoated carbon steel pipe. Drying rate curves for porous materials were also established. A series of aqueous extraction studies was conducted to characterize the durability of various inhibitors on the pipe samples. Results of the study showed that the use of corrosion inhibitors and ensuring the thermal stability of hydrophobing agents will help to prevent CUI. 16 refs., 7 tabs., 17 figs.

  17. Multiplier, moderator, and reflector materials for lithium-vanadium fusion blankets.

    Gohar, Y.; Smith, D. L.


    The self-cooled lithium-vanadium fusion blanket concept has several attractive operational and environmental features. In this concept, liquid lithium works as the tritium breeder and coolant to alleviate issues of coolant breeder compatibility and reactivity. Vanadium alloy (V-4Cr-4Ti) is used as the structural material because of its superior performance relative to other alloys for this application. However, this concept has poor attenuation characteristics and energy multiplication for the DT neutrons. An advanced self-cooled lithium-vanadium fusion blanket concept has been developed to eliminate these drawbacks while maintaining all the attractive features of the conventional concept. An electrical insulator coating for the coolant channels, spectral shifter (multiplier, and moderator) and reflector were utilized in the blanket design to enhance the blanket performance. In addition, the blanket was designed to have the capability to operate at high loading conditions of 2 MW/m{sup 2} surface heat flux and 10 MW/m{sup 2} neutron wall loading. This paper assesses the spectral shifter and the reflector materials and it defines the technological requirements of this advanced blanket concept.

  18. High temperature polymer dielectric film-wire insulation

    Nairus, John G.


    The highlights of the program are outlined including two major accomplishments. TRW identified and demonstrated the potential of two aromatic/heterocyclic polymers to have an outstanding and superior combination of electrical, thermal, and chemical resistance properties versus state-of-the-art Kapton for spacecraft and/or aircraft dielectric insulation applications. (Supporting data is provided in tables.) Feasibility was demonstrated for supporting/enabling technologies such as ceramic coatings, continuous film casting, and conductor wire wrapping, which are designed to accelerate qualification and deployment of the new wire insulation materials for USAF systems applications during the mid- to late-1990's.

  19. Electron beam assisted field evaporation of insulating nanowires/tubes

    Blanchard, N. P., E-mail:; 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)


    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.

  20. Frequency and voltage dependence of electric and dielectric properties of Au/TiO2/n-4H-SiC (metal-insulator-semiconductor) type Schottky barrier diodes

    Tanrıkulu, E. E.; Yıldız, D. E.; Günen, A.; Altındal, Ş.


    The main electrical and dielectric properties of Au/TiO2/n-4H-SiC (MIS) type Schottky barrier diodes (SBDs) have been investigated as functions of frequency and applied bias voltage. We believe that the use of high dielectric interfacial layer between metal and semiconductor can improve the performance of Schottky diodes. From the experimental data, both electrical and dielectric parameters were found as strong function of frequency and applied bias voltage. The Fermi energy level (EF), the concentration of doping donor atoms (P), barrier height (ΦB) and series resistance (Rs) values were obtained from reverse and forward bias C-V characteristics. The changes in EF and ND with frequency are considerably low. Therefore, their values were taken at about constant. The real and imaginary parts of dielectric constant (\\varepsilon \\prime , \\varepsilon \\prime\\prime ), tangent loss (tanδ), ac electrical conductivity (σac), and real and imaginary parts of electric modulus (M‧ and M″) values were also obtained from reverse and forward bias C-V and G/ω-V characteristics. In addition, the voltage dependent profiles of all these electrical and dielectric parameters were drawn for each frequency. These results confirmed that both electrical and dielectric properties of Au/TiO2/n-4H-SiC (MIS) type SBD are quite sensitive to both the frequency and applied bias voltage due to surface polarization, density distribution of interface traps (Dit), and interfacial layer.

  1. A natural topological insulator.

    Gehring, P; Benia, H M; Weng, Y; Dinnebier, R; Ast, C R; Burghard, M; Kern, K


    The earth's crust and outer space are rich sources of technologically relevant materials which have found application in a wide range of fields. Well-established examples are diamond, one of the hardest known materials, or graphite as a suitable precursor of graphene. The ongoing drive to discover novel materials useful for (opto)electronic applications has recently drawn strong attention to topological insulators. Here, we report that Kawazulite, a mineral with the approximate composition Bi2(Te,Se)2(Se,S), represents a naturally occurring topological insulator whose electronic properties compete well with those of its synthetic counterparts. Kawazulite flakes with a thickness of a few tens of nanometers were prepared by mechanical exfoliation. They exhibit a low intrinsic bulk doping level and correspondingly a sizable mobility of surface state carriers of more than 1000 cm(2)/(V s) at low temperature. Based on these findings, further minerals which due to their minimized defect densities display even better electronic characteristics may be identified in the future.

  2. Electromagnetic Scattering by Spheres of Topological Insulators

    Ge, Lixin; Zi, Jian


    The electromagnetic scattering properties of topological insulator (TI) spheres are systematically studied in this paper. Unconventional backward scattering caused by the topological magneto-electric (TME) effect of TIs are found in both Rayleigh and Mie scattering regimes. This enhanced backward scattering can be achieved by introducing an impedance-matched background which can suppress the bulk scattering. For the cross-polarized scattering coefficients, interesting antiresonances are found in the Mie scattering regime, wherein the cross-polarized electromagnetic fields induced by the TME effect are trapped inside TI spheres. In the Rayleigh limit, the quantized TME effect of TIs can be determined by measuring the electric-field components of scattered waves in the far field.

  3. Structural and Electrical Characteristics of Metal-Ferroelectric Pb1.1(Zr0.40Ti0.60O3-Insulator (ZnO-Silicon Capacitors for Nonvolatile Applications

    S. R. Krishnamoorthi


    Full Text Available In this work metal-ferroelectric-insulator-semiconductor (MFIS thin-film structures using Pb1.1Zr0.40Ti0.60O3 (PZT as the ferroelectric layer and zinc oxide (ZnO as the insulator layer were fabricated on n-type (100 Si substrate. Pb1.1Zr0.40Ti0.60O3 and ZnO thin films were prepared on Si by the sol-gel route and thermal deposition method, respectively. On the optimized PZT (140 nm and ZnO (40 nm films were examined by scanning electron microscope (SEM. From AFM data the root mean square (r.m.s. roughness of the film surface is 13.11 nm. The leakage current density of ZnO/n-Si (MIS structure was as low as 1.8 × 10−8 A/cm2 at 2.5 V. The capacitance versus voltage (C-V characteristics of the annealed ZnO/Si (MIS diode indicated the good interface properties and no hysteresis was observed. Au/PZT (140 nm/ZnO (40 nm/Si (100 leakage-current density was about 5.7 × 10−8 A/cm2 at positive bias voltage of 3 V. The large memory window width in C-V (capacitance-voltage curve of Au/PZT/ZnO/Si capacitor was about 2.9 V under ±12 V which thus possibly enables nonvolatile applications. The memory window as a function of temperature was also discussed.

  4. Optimum Scheme for Insulation System in HV Generator Based on Electromagnetic Analysis

    A. Gholami


    Full Text Available Electrical insulations are one of the basic parts of electrical machinery in any sizes and characteristics. Focusing on insulating, studies on the operation of industrial-electrical machinery came to the fact that the most important part of a machine is the Stator. This fact reveals the requirement for inspection of the electrical machine insulation along with the electromagnetic tensions. Therefore with respect to insulation system improvement of stator, the HV generator can be optimized. Dielectric parameters such as insulation thickness, spacing, material types, geometry of winding and slot are major design consideration. A very powerful method available to analyze electromagnetic performance is Finite Element Method (FEM which is used in this paper. The analysis of various stator coil and slot configurations are used to design the better dielectric system to reduce electrical stresses in order to increase the power of generator in the same volume of core. These processes of optimization have been done according the proposed algorithm. In this algorithm the technical constraints have been considered. This paper describes the process used to perform classical design and improvement analysis of stator slot’s insulation with respect to objective function and constraints.

  5. Ceramic processing of boron nitride insulators

    Morgan, C. S.; McCulloch, R. W.


    Fuel pin simulators (FPS) are the prime elements of several test facilities at the Oak Ridge National Laboratory (ORNL). These experimental facilities are used to conduct out-of-reactor thermal-hydraulic and mechanical interaction safety tests for both light-water and breeder reactor programs. The FPS units simulate the geometry, heat flux profiles, and operational capabilities of a reactor core element under steady-state and transient conditions. They are subjected to temperatures as high as 1600/sup 0/C (2900/sup 0/F) and power levels as high as 57.5 kW/m (17.5 kW/ft) as well as severe thermal stresses during transient tests. The insulating material in the narrow annulus between the heating coil and the FPS sheath is subjected to very rigorous conditions. Accuracy of the reactor safety test information and validity of the test data depend on the heat flux uniformity under all test conditions and on the reliable operation of all fuel pin simulators and their internal thermocouples. Boron nitride (BN), because of its high degree of chemical inertness combined with its relatively unique properties of high thermal conductivity and low electrical conductivity, is the most suitable insulating material for FPS. The important BN properties, thermal conductivity and electrical resistance, are strongly influenced by crystallite orientation and by impurities. The article describes new BN powder processing techniques, which optimize these properties.

  6. The birth of topological insulators.

    Moore, Joel E


    Certain insulators have exotic metallic states on their surfaces. These states are formed by topological effects that also render the electrons travelling on such surfaces insensitive to scattering by impurities. Such topological insulators may provide new routes to generating novel phases and particles, possibly finding uses in technological applications in spintronics and quantum computing.

  7. Tailorable Advanced Blanket Insulation (TABI)

    Sawko, Paul M.; Goldstein, Howard E.


    Single layer and multilayer insulating blankets for high-temperature service fabricated without sewing. TABI woven fabric made of aluminoborosilicate. Triangular-cross-section flutes of core filled with silica batting. Flexible blanket formed into curved shapes, providing high-temperature and high-heat-flux insulation.

  8. Topological Insulators from Electronic Superstructures

    Sugita, Yusuke; Motome, Yukitoshi


    The possibility of realizing topological insulators by the spontaneous formation of electronic superstructures is theoretically investigated in a minimal two-orbital model including both the spin-orbit coupling and electron correlations on a triangular lattice. Using the mean-field approximation, we show that the model exhibits several different types of charge-ordered insulators, where the charge disproportionation forms a honeycomb or kagome superstructure. We find that the charge-ordered insulators in the presence of strong spin-orbit coupling can be topological insulators showing quantized spin Hall conductivity. Their band gap is dependent on electron correlations as well as the spin-orbit coupling, and even vanishes while showing the massless Dirac dispersion at the transition to a trivial charge-ordered insulator. Our results suggest a new route to realize and control topological states of quantum matter by the interplay between the spin-orbit coupling and electron correlations.

  9. Technology Solutions Case Study: Insulating Concrete Forms



    This Pacific Northwest National Laboratory project investigated insulating concrete forms—rigid foam, hollow walls that are filled with concrete for highly insulated, hurricane-resistant construction.

  10. Electrified magnetic catalysis in three-dimensional topological insulators

    Gorbar, E. V.; Miransky, V. A.; Shovkovy, I. A.; Sukhachov, P. O.


    The gap equations for the surface quasiparticle propagators in a slab of three-dimensional topological insulator in external electric and magnetic fields perpendicular to the slab surfaces are analyzed and solved. A different type of magnetic catalysis is revealed with the dynamical generation of both Haldane and Dirac gaps. Its characteristic feature manifests itself in the crucial role that the electric field plays in dynamical symmetry breaking and the generation of a Dirac gap in the slab. It is argued that, for a sufficiently large external electric field, the ground state of the system is a phase with a homogeneous surface charge density.

  11. Electrified magnetic catalysis in 3D topological insulators

    Gorbar, E V; Shovkovy, I A; Sukhachov, P O


    The gap equations for the surface quasiparticle propagators in a slab of three-dimensional topological insulator in external electric and magnetic fields perpendicular to the slab surfaces are analyzed and solved. A new type of magnetic catalysis is revealed with the dynamical generation of both Haldane and Dirac gaps. Its characteristic feature manifests itself in the crucial role that the electric field plays in dynamical symmetry breaking and the generation of a Dirac gap in the slab. It is argued that, for a sufficiently large external electric field, the ground state of the system is a phase with a homogeneous surface charge density.

  12. Bio-Inspired Concepts: Studies of Biological Response to External Electric Fields for Cellular Manipulation and Diagnostics - Modeling and Experimentation


    Dielectric Spectroscopy," IEEE trans. On Dielectrics and Electrical Insulation 8, 253 (2001). 8. M. Smoluchowski, "Drei vortrage uber diffusion...Intensity Electric Fields," IEEE Conf. On Dielectrics and Electrical Insulation (Bio- Electrics Workshop), Cancun, Mexico , Oct. 2002 (invited

  13. Perspectives on Magnetized Target Fusion Power Plants

    Miller, R. L.


    One approach to Magnetized Target Fusion (MTF) builds upon the ongoing experimental effort (FRX-L) to generate a Field Reversed Configuration (FRC) target plasma suitable for translation and cylindrical-liner (i.e., converging flux conserver) implosion. Numerical modeling is underway to elucidate key performance drivers for possible future power-plant extrapolations. The fusion gain, Q (ratio of DT fusion yield to the sum of initial liner kinetic energy plus plasma formation energy), sets the power-plant duty cycle for a nominal design electric power [ e.g. 1,000 MWe(net)]. A pulsed MTF power plant of this type derives from the historic Fast Liner Reactor (FLR) concept and shares attributes with the recent Inertial Fusion Energy (IFE) Z-pinch and laser-driven pellet HYLIFE-II conceptual designs.

  14. Deactivating Metal Particle by Optimizing Insulation Configuration in Spark Gap Switch

    JIA Jiangbo; ZHANG Qiaogen; ZHU Taiyun; ZHA Wei; SUN Fu; YANG Lanjun


    -As a new method to protect the spark gap from metal particle contamination, the effect of the metal inserted insulator on the controlling behavior of metal particles was investigated in a quasi-uniform electric field. Considering that the inserted metal electrodes can decrease the electric field around the insulator and divert the electrostatic force away from the insulator, the method can be used to prevent the particles from moving toward the insulator so as to reduce the possibility of a breakdown. The inserted metal electrodes can reverse the direction of the particles' horizontal motion. A study on the insulator shape indicates that the inserted metal electrodes can repulse the particle and improve the particle lifting voltage significantly near the vertical surface of the insulator or ribbed insulator. For the insulator with a tilting surface the inserted metal electrodes have little influence on the particle motion. In addition, the size of the inserted electrodes shows a significant effect on the control of particle motion.

  15. The ECG measurement in the bathtub using the insulated electrodes.

    Lim, Yong Kyu; Kim, Ko Keun; Park, Kwang Suk


    The ECG recording in the bathtub was studied using insulated electrode. Prior studies of the ECG recording in the bathtub used conductive electrodes having some problems such as the possibility of the electric shock and sensitivity to contamination of the electrode surfaces. The insulated electrodes were made of copper plate coated with PET film. The electrodes were attached on bathtub at both sides of the chest. High-input-impedance amplifier was designed to amplify ECG signal sensed by insulated electrodes of high impedance. The recorded signals in this study were noisier than those recorded with conventional conductive electrodes. But the R peaks in the recorded signals were large enough to be auto-detected. Further study will improve SNR by reducing of power line noise and common-mode noise.

  16. The Electromagnetic Green's Function for Layered Topological Insulators

    Crosse, J A; Buhmann, Stefan Yoshi


    The dyadic Green's function of the inhomogeneous vector Helmholtz equation describes the field pattern of a single frequency point source. It appears in the mathematical description of many areas of electromagnetism and optics including both classical and quantum, linear and nonlinear optics, dispersion forces (such as the Casimir and Casimir-Polder forces) and in the dynamics of trapped atoms and molecules. Here, we compute the Green's function for a layered topological insulator. Via the magnetoelectric effect, topological insulators are able to mix the electric, E, and magnetic induction, B, fields and, hence, one finds that the TE and TM polarizations mix on reflection from/transmission through an interface. This leads to novel field patterns close to the surface of a topological insulator.

  17. Low voltage n-type OFET based on double insulators

    ZHOU Jian-lin; ZHANG Fu-jia


    A top contact n-type organic field-effect transistor with low operating voltage was fabricated by employing Ta2O5/PMMA as the double insulators and PTCDI-Cl2 as the semiconductor active layer. The Ta2O5 layer was prepared by using simple economical anodization technique and the PMMA layer was prepared by using the spin-coating method. Compared with the OFET with single Ta2O5 insulator, the device with double insulators shows obviously better electrical performance. It has a field effect electron mobility of 0.063 cm2/Vs, an on/offratio of 1.7×104 and a threshold voltage of 2.3 V.

  18. Disorder enabled band structure engineering of a topological insulator surface

    Xu, Yishuai; Chiu, Janet; Miao, Lin; He, Haowei; Alpichshev, Zhanybek; Kapitulnik, A.; Biswas, Rudro R.; Wray, L. Andrew


    Three-dimensional topological insulators are bulk insulators with Z2 topological electronic order that gives rise to conducting light-like surface states. These surface electrons are exceptionally resistant to localization by non-magnetic disorder, and have been adopted as the basis for a wide range of proposals to achieve new quasiparticle species and device functionality. Recent studies have yielded a surprise by showing that in spite of resisting localization, topological insulator surface electrons can be reshaped by defects into distinctive resonance states. Here we use numerical simulations and scanning tunnelling microscopy data to show that these resonance states have significance well beyond the localized regime usually associated with impurity bands. At native densities in the model Bi2X3 (X=Bi, Te) compounds, defect resonance states are predicted to generate a new quantum basis for an emergent electron gas that supports diffusive electrical transport.

  19. Cold nuclear fusion

    Huang Zhenqiang Huang Yuxiang


    ...... And with a magnetic moment of light nuclei controlled cold nuclear collide fusion, belongs to the nuclear energy research and development in the field of applied technology "cold nuclear collide fusion...

  20. Homeowners' demand for home insulation



    The survey was conducted to provide guidance based on the views and experience of a national sample of homeowners about the insulation of their homes. The telephone survey was conducted with 1,012 homeowners between January 12 and 22, 1978 in the East, Midwest, South, and West regions of the U.S. From the survey data were compiled on plans for installing home insulation with emphasis on attic insulation; how many homes now have various types of insulation; recent experiences in obtaining attic insulation--its cost, material used, when installed, whether installed by the homeowner or a contractor; the kinds of insulation thought to be needed--attic insulation, wall insulation, storm doors and windows; whether homeowners planning attic insulation feel that they have the necessary information to do the work themselves or if they feel they know enough to make the necessary arrangements with a contractor; the effect of higher fuel costs on likelihood of installing attic insulation; shortages of insulating materials; what sources of information are relied on when planning attic insulation; attitudes toward having utility companies install insulation to be paid for by means of utility bills; how much trust homeowners have in the advice of government, utility companies, insulation manufacturers, insulation installers, and retail stores about how much insulation is needed; the likely effect of a tax credit on plans to insulate the attic; and the concern about energy shortages.

  1. Insulation. [In the glass industry

    Perkins, J.M.; Horsfield, M.; Jackson, J.D.J.; Woodhead, D.


    Furnace insulation in the glass industry is becoming increasingly important as fuel prices rise. Refractory materials with a large number of small pores separated from each other by very thin membranes of refractory produce good insulation. Four main types are used to cope efficiently with the range of temperature involved and the different areas of application. Insulation intended for use at very high temperatures is not as efficient as some of the low temperature materials consequently the insulation is built up in several layers to obtain the optimum efficiency. Insulating bricks are available for various temperatures up to 1850{sup 0}C depending on their chemical composition. Castables, produced by mixing high alumina cements and light-weight refractory aggregates, are quick to install and can be formed into any shape or size. Ceramic fibres felted together to form low density, highly porous, blankets, boards, paper and modules can be used up to 1600{sup 0}C. Microporous insulation based on an ultrafine powder of amorphous silica has a limited temperature range, is subject to chemical attack and abrasion, but has the lowest thermal conductivity of any insulation material available. Criteria for the use of materials in different furnace areas and examples of their application are given. (U.K.).

  2. Insulation and Heat Treatment of Bi-2212 Wire for Wind-and-React Coils

    Peter K. F. Hwang


    Higher Field Magnets demand higher field materials such as Bi-2212 round superconducting wire. The Bi-2212 wire manufacture process depends on the coil fabrication method and wire insulation material. Considering the wind-and-react method, the coil must unifirmly heated to the melt temperature and uniformly cooled to the solidification temperature. During heat treat cycle for tightly wound coils, the leakage melt from conductor can chemically react with insulation on the conductor and creat short turns in the coils. In this research project, conductor, insulation, and coils are made to systemically study the suitable insulation materials, coil fabrication method, and heat treatment cycles. In this phase I study, 800 meters Bi-2212 wire with 3 different insulation materials have been produced. Best insulation material has been identified after testing six small coils for insulation integrity and critical current at 4.2 K. Four larger coils (2" dia) have been also made with Bi-2212 wrapped with best insulation and with different heattreatment cycle. These coils were tested for Ic in a 6T background field and at 4.2 K. The test result shows that Ic from 4 coils are very close to short samples (1 meter) result. It demonstrates that HTS coils can be made with Bi-2212 wire with best insulation consistently. Better wire insulation, improving coil winding technique, and wire manufacture process can be used for a wide range of high field magnet application including acclerators such as Muon Collider, fusion energy research, NMR spectroscopy, MRI, and other industrial magnets.

  3. Cold fusion research



    I am pleased to forward to you the Final Report of the Cold Fusion Panel. This report reviews the current status of cold fusion and includes major chapters on Calorimetry and Excess Heat, Fusion Products and Materials Characterization. In addition, the report makes a number of conclusions and recommendations, as requested by the Secretary of Energy.

  4. The status maintenance for electrical insulator of high voltage power transmission lines%高压输电线路绝缘子状态检修的研究

    刘玉; 饶雪


    随着供电技术装备水平和管理水平的提高,定期检修的不足之处越来越凸显出来,亟需一种新的检修制度来弥补这种不足,这种新的检修方式就是状态检修.本文结合我国输配电线路主设备状态检修的具体实际,介绍了输配线路状态检修的内容,重点介绍了绝缘子的状态检修.%With the power supply technology and equipment and management level,lack of regular maintenance of the more prominent place in urgent need of a new maintenance system to compensate for this Kinds of lack of maintenance of this new way to condition-based maintenance.In this paper,the main transmission lines of the specific conditions of state maintenance equipment,introduces the state of maintenance of the transmission line content,especially the status maintenance of insulator.

  5. Insulation system in an integrated motor compressor

    Sihvo, V.


    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

  6. Insulated conductor temperature limited heater for subsurface heating coupled in a three-phase WYE configuration

    Vinegar, Harold J. (Bellaire, TX); Sandberg, Chester Ledlie (Palo Alto, CA)


    A heating system for a subsurface formation is described. The heating system includes a first heater, a second heater, and a third heater placed in an opening in the subsurface formation. Each heater includes: an electrical conductor; an insulation layer at least partially surrounding the electrical conductor; and an electrically conductive sheath at least partially surrounding the insulation layer. The electrical conductor is electrically coupled to the sheath at a lower end portion of the heater. The lower end portion is the portion of the heater distal from a surface of the opening. The first heater, the second heater, and the third heater are electrically coupled at the lower end portions of the heaters. The first heater, the second heater, and the third heater are configured to be electrically coupled in a three-phase wye configuration.

  7. Study of Temperature Distribution Along an Artificially Polluted Insulator String


    Insulator becomes wet partially or completely, and the pollution layer on it becomes conductive, when collecting pollutants for an extended period during dew, light rain, mist, fog or snow melting. Heavy rain is a complicated factor that it may wash away the pollution layer without initiating other stages of breakdown or it may bridge the gaps between sheds to promote flashover.The insulator with a conducting pollution layer being energized, can cause a surface leakage current to flow (also temperature-rise). As the surface conductivity is non-uniform, the conducting pollution layer becomes broken by dry bands (at spots of high current density), interrupting the flow of leakage current. Voltage across insulator gets concentrated across dry bands, and causes high electric stress and breakdown (dry band arcing). If the resistance of the insulator surface is sufficiently low, the dry band arcs can be propagated to bridge the terminals causing flashover.The present paper concerns the evaluation of the temperature distribution along the surface of an energized artificially polluted insulator string.

  8. Nuclear Propulsion through Direct Conversion of Fusion Energy: The Fusion Driven Rocket

    Slough, John; Pancotti, Anthony; Kirtley, David; Pihl, Christopher; Pfaff, Michael


    The future of manned space exploration and development of space depends critically on the creation of a dramatically more proficient propulsion architecture for in-space transportation. A very persuasive reason for investigating the applicability of nuclear power in rockets is the vast energy density gain of nuclear fuel when compared to chemical combustion energy. Current nuclear fusion efforts have focused on the generation of electric grid power and are wholly inappropriate for space transportation as the application of a reactor based fusion-electric system creates a colossal mass and heat rejection problem for space application.

  9. The Sustainable Nuclear Future: Fission and Fusion E.M. Campbell Logos Technologies

    Campbell, E. Michael


    Global industrialization, the concern over rising CO2 levels in the atmosphere and other negative environmental effects due to the burning of hydrocarbon fuels and the need to insulate the cost of energy from fuel price volatility have led to a renewed interest in nuclear power. Many of the plants under construction are similar to the existing light water reactors but incorporate modern engineering and enhanced safety features. These reactors, while mature, safe and reliable sources of electrical power have limited efficiency in converting fission power to useful work, require significant amounts of water, and must deal with the issues of nuclear waste (spent fuel), safety, and weapons proliferation. If nuclear power is to sustain its present share of the world's growing energy needs let alone displace carbon based fuels, more than 1000 reactors will be needed by mid century. For this to occur new reactors that are more efficient, versatile in their energy markets, require minimal or no water, produce less waste and more robust waste forms, are inherently safe and minimize proliferation concerns will be necessary. Graphite moderated, ceramic coated fuel, and He cooled designs are reactors that can satisfy these requirements. Along with other generation IV fast reactors that can further reduce the amounts of spent fuel and extend fuel resources, such a nuclear expansion is possible. Furthermore, facilities either in early operations or under construction should demonstrate the next step in fusion energy development in which energy gain is produced. This demonstration will catalyze fusion energy development and lead to the ultimate development of the next generation of nuclear reactors. In this presentation the role of advanced fission reactors and future fusion reactors in the expansion of nuclear power will be discussed including synergies with the existing worldwide nuclear fleet. )


    M. I. Kapitsa


    Full Text Available The mathematical model for determination of remaining resource of insulation of the locomotive hauling electric machines, taking into account its initial electric durability and minimum expenses on implementation of restoration works with the purpose of construction of the rational system of its maintenance, is offered.

  11. Control of a laser inertial confinement fusion-fission power plant

    Moses, Edward I.; Latkowski, Jeffery F.; Kramer, Kevin J.


    A laser inertial-confinement fusion-fission energy power plant is described. The fusion-fission hybrid system uses inertial confinement fusion to produce neutrons from a fusion reaction of deuterium and tritium. The fusion neutrons drive a sub-critical blanket of fissile or fertile fuel. A coolant circulated through the fuel extracts heat from the fuel that is used to generate electricity. The inertial confinement fusion reaction can be implemented using central hot spot or fast ignition fusion, and direct or indirect drive. The fusion neutrons result in ultra-deep burn-up of the fuel in the fission blanket, thus enabling the burning of nuclear waste. Fuels include depleted uranium, natural uranium, enriched uranium, spent nuclear fuel, thorium, and weapons grade plutonium. LIFE engines can meet worldwide electricity needs in a safe and sustainable manner, while drastically shrinking the highly undesirable stockpiles of depleted uranium, spent nuclear fuel and excess weapons materials.

  12. 16 CFR 460.18 - Insulation ads.


    ... 16 Commercial Practices 1 2010-01-01 2010-01-01 false Insulation ads. 460.18 Section 460.18 Commercial Practices FEDERAL TRADE COMMISSION TRADE REGULATION RULES LABELING AND ADVERTISING OF HOME INSULATION § 460.18 Insulation ads. (a) If your ad gives an R-value, you must give the type of insulation...

  13. Fission Fusion Hybrids: a nearer term application of Fusion

    Kotschenreuther, M.; Valanju, P.; Mahajan, S.; Covele, B.


    Fission-fusion hybrids enjoy unique advantages for addressing long standing societal acceptability issues of nuclear fission power at a much lower level of technical development than a competitive fusion power plant. For waste incineration, hybrids burn intransigent transuranic residues (with the long lived biohazard) from light water reactors (LWRs). The number of hybrids needed is 5-10 times less than the corresponding number of fast reactors (FRs). The highly sub-critical hybrids, with a thermal/epithermal spectrum, incinerate > 95% of the waste in decades rather than the centuries needed for FRs. For fuel production, hybrids can produce fuel for 3-4 times as many LWRs with no fuel reprocessing. Thorium fuel rods exposed to neutrons in the hybrid reach fissile concentrations that enable efficient burning in LWR without the proliferation risks of reprocessing. The proliferation risks of this method are far less than other fuel breeding approaches, including today's gas centrifuge. With this cycle, US Thorium reserves could supply the entire US electricity supply for centuries. The centerpiece of the fuel cycle is a high power density Compact Fusion Neutron Source (major+minor radius ~ 2.5-3.5 m), which is made feasible by the super-X divertor.

  14. Mechanical and Thermal Characteristics of Insulation Materials for the KSTAR Magnet System at Cryogenic Temperature

    Chung, Wooho; Lim, Bungsu; Kim, Myungkyu; Park, Hyunki; Kim, Keeman; Chu, Yong; Lee, Sangil


    The KSTAR(Korea Superconducting Tokamak Advanced Research) superconducting magnet is electrically insulated by the composite material of epoxy resin and glass fiber (2.5 kV/mm) and Kapton (8 kV/mm). The insulation composite material of epoxy resin and glass fiber is prepared using a VPI (Vacuum Pressure Impregnation) process. The superconducting magnet is under mechanical stress caused by the large temperature difference between the operation temperature of the magnet and room temperature. The large electro-magnetic force during the operation of the magnet is also exerted on the magnet. Therefore, the characteristics of the insulation material at cryogenic temperatures are very important and the tensile stress and thermal expansion coefficient for the insulation materials of the KSTAR superconducting magnet are measured. This paper presents results on mechanical properties of the insulation material for KSTAR magnets, such as density, ultimate tensile stress and thermal contraction between room temperature and cryogenic temperatures.

  15. Impedance Characterization of the Degradation of Insulating Layer Patterned on Interdigitated Microelectrode.

    Lee, Gihyun; Kim, Sohee; Cho, Sungbo


    Life-time and functionality of planar microelectrode-based devices are determined by not only the corrosion-resistance of the electrode, but also the durability of the insulation layer coated on the transmission lines. Degradation of the insulating layer exposed to a humid environment or solution may cause leakage current or signal loss, and a decrease in measurement sensitivity. In this study, degradation of SU-8, an epoxy-based negative photoresist and insulating material, patterned on Au interdigitated microelectrode (IDE) for long-term (>30 days) immersion in an electrolyte at 37 °C was investigated by electrical impedance spectroscopy and theoretical equivalent circuit modeling. From the experiment and simulation results, it was found that the degradation level of the insulating layer of the IDE electrode can be characterized by monitoring the resistance of the insulating layer among the circuit parameters of the designed equivalent circuit modeling.

  16. Viral membrane fusion

    Harrison, Stephen C., E-mail:


    Membrane fusion is an essential step when enveloped viruses enter cells. Lipid bilayer fusion requires catalysis to overcome a high kinetic barrier; viral fusion proteins are the agents that fulfill this catalytic function. Despite a variety of molecular architectures, these proteins facilitate fusion by essentially the same generic mechanism. Stimulated by a signal associated with arrival at the cell to be infected (e.g., receptor or co-receptor binding, proton binding in an endosome), they undergo a series of conformational changes. A hydrophobic segment (a “fusion loop” or “fusion peptide”) engages the target-cell membrane and collapse of the bridging intermediate thus formed draws the two membranes (virus and cell) together. We know of three structural classes for viral fusion proteins. Structures for both pre- and postfusion conformations of illustrate the beginning and end points of a process that can be probed by single-virion measurements of fusion kinetics. - Highlights: • Viral fusion proteins overcome the high energy barrier to lipid bilayer merger. • Different molecular structures but the same catalytic mechanism. • Review describes properties of three known fusion-protein structural classes. • Single-virion fusion experiments elucidate mechanism.

  17. Metal-Insulator-Semiconductor Photodetectors

    Chu-Hsuan Lin


    Full Text Available The major radiation of the Sun can be roughly divided into three regions: ultraviolet, visible, and infrared light. Detection in these three regions is important to human beings. The metal-insulator-semiconductor photodetector, with a simpler process than the pn-junction photodetector and a lower dark current than the MSM photodetector, has been developed for light detection in these three regions. Ideal UV photodetectors with high UV-to-visible rejection ratio could be demonstrated with III-V metal-insulator-semiconductor UV photodetectors. The visible-light detection and near-infrared optical communications have been implemented with Si and Ge metal-insulator-semiconductor photodetectors. For mid- and long-wavelength infrared detection, metal-insulator-semiconductor SiGe/Si quantum dot infrared photodetectors have been developed, and the detection spectrum covers atmospheric transmission windows.

  18. Measure Guideline: Basement Insulation Basics

    Aldrich, R.; Mantha, P.; Puttagunta, S.


    This guideline is intended to describe good practices for insulating basements in new and existing homes, and is intended to be a practical resources for building contractors, designers, and also to homeowners.

  19. Metal-insulator-semiconductor photodetectors.

    Lin, Chu-Hsuan; Liu, Chee Wee


    The major radiation of the sun can be roughly divided into three regions: ultraviolet, visible, and infrared light. Detection in these three regions is important to human beings. The metal-insulator-semiconductor photodetector, with a simpler process than the pn-junction photodetector and a lower dark current than the MSM photodetector, has been developed for light detection in these three regions. Ideal UV photodetectors with high UV-to-visible rejection ratio could be demonstrated with III-V metal-insulator-semiconductor UV photodetectors. The visible-light detection and near-infrared optical communications have been implemented with Si and Ge metal-insulator-semiconductor photodetectors. For mid- and long-wavelength infrared detection, metal-insulator-semiconductor SiGe/Si quantum dot infrared photodetectors have been developed, and the detection spectrum covers atmospheric transmission windows.

  20. Electrical Tests of Super-hydrophobic Coating in Early Stage of Icing on Insulators%一种绝缘子超疏水防覆冰涂层覆冰初期的电气试验研究

    杨洋; 黄文龙; 李剑; 许强; 陈安明


    为有效地减少绝缘子覆冰事故的发生,笔者通过在低表面能疏水性材料表面化学沉积纳米粒子的方法自制一种绝缘子超疏水涂层,涂层表面具有类荷叶的微纳米二元复合粗糙结构,其上水滴静态接触角可以达到(160±0.5)°.将涂敷有此种超疏水涂层的等腰三角形玻璃板、涂敷RTV涂层的等腰三角形玻璃板与没有涂层的等腰三角形玻璃板一起放入人工覆冰实验室,覆冰1h后对这3种试品进行电气试验,包括20 kV测试电压下的泄漏电流试验以及紫外成像试验.试验结果表明,超疏水涂层在覆冰初期能够有效地减少覆冰量及阻止连续覆冰膜的形成的特性,使得涂覆超疏水涂层试品的表面泄漏电流远远低于在覆冰初期就形成连续覆冰膜的另外两种试品,从而在泄漏电流及紫外成像测试中表现出了优越的电气性能.%To effectively reduce icing accidents of insulators, a super-hydrophobic coating with lotus morphology is made for insulators by chemically depositing nano-particles layer on the surface of hydrophobic material. The coating surface is of lotus-like micro-nano binary roughness structure, which makes the contact angle of water reach to (160±0.5)°. Two isoceles triangle glass plates with respective super-hydrophobic coating and RTV coating, as well as one blank isoceles triangle glass plate, are put into the artificial climate chamber for icing. After one hour icing period, the leakage current test and ultraviolet imaging test are conducted on the three samples under 20 kV voltage. The results indicate that the super-hydrophobic coating can apparently slow icing process, decrease ice quantity, and form a unique ice surface composed of small and separated ice particles in early icing stage to prevent formation of continuous ice layer, which makes the leakage current much smaller than that of other two samples on which continuous ice layers already form in early icing stage