WorldWideScience

Sample records for electrical insulation caused

  1. Electric fields and electrical insulation

    DEFF Research Database (Denmark)

    McAllister, Iain Wilson

    2002-01-01

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

  2. Electrical insulator assembly with oxygen permeation barrier

    Science.gov (United States)

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

    1994-01-01

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

  3. Insulation assembly for electric machine

    Science.gov (United States)

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

    2013-10-15

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

  4. Electrically Tunable Magnetism in Magnetic Topological Insulators.

    Science.gov (United States)

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

    2015-07-17

    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.

  5. Electrically Tunable Magnetism in Magnetic Topological Insulators

    Energy Technology Data Exchange (ETDEWEB)

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

    2015-07-14

    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. Effect of electrically insulating materials on magnetically induced electrical currents in a tissue-like medium

    Science.gov (United States)

    Hoffmeister, Brent K.; Shores, Andrew R.; Banerjee, Shubho; Malkin, Robert A.

    2006-04-01

    Time varying magnetic fields can induce eddy currents in a conductor. Electrical currents also can be induced magnetically in the human body, and there has been considerable interest in the bioeffects of this phenomenon. We present an analytical model derived from Faraday's law and Coulomb's law that provides physical insight into how electrically insulating materials in a tissue-like medium redirect magnetically induced currents. The model shows that charge accumulates at the tissue-insulator interface to produce a secondary electric field. This field combines with the magnetically induced electric field to alter the net electric field in the vicinity of the insulator, causing the electric current to flow around the insulator. The model is supplemented by measurements of magnetically induced electric fields in a volume of physiologic saline solution. Good agreement is found among the model, the measurements, and a finite element analysis model of the experiment.

  7. Electrical control of spin in topological insulators

    Science.gov (United States)

    Chang, Kai

    2012-02-01

    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

  8. Self-Healable Electrical Insulation for High Voltage Applications

    Science.gov (United States)

    Williams, Tiffany S.

    2017-01-01

    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.

  9. Modification of electrical properties of topological insulators

    Energy Technology Data Exchange (ETDEWEB)

    Sharma, Peter Anand

    2017-08-29

    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

    Science.gov (United States)

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

    2013-01-01

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

    Science.gov (United States)

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false 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...

  12. 30 CFR 75.513 - Electric conductor; capacity and insulation.

    Science.gov (United States)

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Electric conductor; capacity and insulation. 75... MINE SAFETY AND HEALTH MANDATORY SAFETY STANDARDS-UNDERGROUND COAL MINES Electrical Equipment-General § 75.513 Electric conductor; capacity and insulation. All electric conductors shall be sufficient in...

  13. High voltage and electrical insulation engineering

    CERN Document Server

    Arora, Ravindra

    2011-01-01

    "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. Effects of thermal insulation on electrical connections and outlet boxes

    Science.gov (United States)

    Beausoliel, R. W.; Clifton, J. R.; Meese, W. J.

    1981-04-01

    When residential walls are retrofitted with foamed-in urea formaldehyde or blown-in cellulose thermal insulations, the insulation may enter electrical outlet and switch boxes. The effects of these thermal insulations on the durability of electrical components were studied. These studies were carried out at 44, 75, and 96 percent relative humidities with test periods between one and twelve months. Laboratory test methods were developed and tests performed to determine the electrical and corrosive effects of urea formaldehyde and cellulose thermal insulation contained in electrical outlet and switch boxes.

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

    Directory of Open Access Journals (Sweden)

    Issouf Fofana

    2016-08-01

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

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

    Science.gov (United States)

    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.

  17. Switching a normal insulator into a topological insulator via electric field with application to phosphorene.

    Science.gov (United States)

    Liu, Qihang; Zhang, Xiuwen; Abdalla, L B; Fazzio, Adalberto; Zunger, Alex

    2015-02-11

    The study of topological insulators has generally involved search of materials that have this property as an innate quality, distinct from normal insulators. Here we focus on the possibility of converting a normal insulator into a topological one by application of an external electric field that shifts different bands by different energies and induces a specific band inversion, which leads to a topological state. Phosphorene is a two-dimensional (2D) material that can be isolated through mechanical exfoliation from layered black phosphorus, but unlike graphene and silicene, single-layer phosphorene has a large band gap (1.5-2.2 eV). Thus, it was unsuspected to exhibit band inversion and the ensuing topological insulator behavior. Using first-principles calculations with applied perpendicular electric field F⊥ on few-layer phosphorene we predict a continuous transition from the normal insulator to a topological insulator and eventually to a metal as a function of F⊥. The tuning of topological behavior with electric field would lead to spin-separated, gapless edge states, that is, quantum spin Hall effect. This finding opens the possibility of converting normal insulating materials into topological ones via electric field and making a multifunctional "field effect topological transistor" that could manipulate simultaneously both spin and charge carrier. We use our results to formulate some design principles for looking for other 2D materials that could have such an electrical-induced topological transition.

  18. Gaseous insulators for high voltage electrical equipment

    Science.gov (United States)

    Christophorou, Loucas G.; James, David R.; Pace, Marshall O.; Pai, Robert Y.

    1979-01-01

    Gaseous insulators comprise compounds having high attachment cross sections for electrons having energies in the 0-1.3 electron volt range. Multi-component gaseous insulators comprise compounds and mixtures having overall high electron attachment cross sections in the 0-1.3 electron volt range and moderating gases having high cross sections for inelastic interactions with electrons of energies 1-4 electron volts. Suitable electron attachment components include hexafluorobutyne, perfluorobutene-2, perfluorocyclobutane, perfluorodimethylcyclobutane, perfluorocyclohexene, perfluoromethylcyclohexane, hexafluorobutadiene, perfluoroheptene-1 and hexafluoroazomethane. Suitable moderating gases include N.sub.2, CO, CO.sub.2 and H.sub.2. The gaseous insulating mixture can also contain SF.sub.6, perfluoropropane and perfluorobenzene.

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

    Directory of Open Access Journals (Sweden)

    M. Arastounia

    2013-10-01

    Full Text Available 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

  20. 30 CFR 27.36 - Test for adequacy of electrical insulation and clearances.

    Science.gov (United States)

    2010-07-01

    ... Test for adequacy of electrical insulation and clearances. MSHA shall examine, and test in a manner it deems suitable, electrical insulation and clearances between electrical conductors to determine adequacy... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Test for adequacy of electrical insulation and...

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

    Energy Technology Data Exchange (ETDEWEB)

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

    1987-12-31

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

  2. A concept for the intrinsic dielectric strength of electrical insulation materials

    Science.gov (United States)

    Cuddihy, E. F.

    1985-04-01

    A concept is described for a possible definition of the intrinsic dielectric strength of insulating materials, which can be considered as a fundamental material property similar to other material properties, such as Young's modulus, index of refraction, and expansion coefficients. The events leading to the recognition of this property are reported, and the property is defined. This intrinsic dielectric strength concept should facilitate interpretation of results from accelerated and/or natural aging programs intended to predict electrical insulation service life of encapsulants in photovoltaic modules. As a practical application, this new concept enabled a possible explanation of the cause of failures in buried high-voltage cable with polyethylene insulation, and a possible explanation of the causes of electrical trees in polyethylene; these also are described.

  3. Electrically and Thermally Insulated Joint for Liquid Nitrogen Transfer

    DEFF Research Database (Denmark)

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

    1999-01-01

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

  4. SAFETY ALERT: Electrical insulation defect on safety helmets

    CERN Multimedia

    HSE Unit

    2013-01-01

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

  5. CHARACTERIZATION OF ELECTRICAL PORCELAIN INSULATORS FROM LOCAL CLAYS

    OpenAIRE

    Okolo Chidiebere Cajetan; Ezechukwu O.A.; Olisakwe C.O.; Ezendokwelu C.E.; Umunna Chike

    2017-01-01

    In this thesis, the characterization of electrical porcelain insulators based on local clays has been investigated. Test samples were made by varying the quantities of feldspar and silica required to form a mouldable plastic body with each clay sample. The clay samples were bisque fired which is to 900°C and glazed before it was fired to 1250°C after air-drying. An electrical property such as dielectric strength (breakdown voltage) was determined for each test sample that survived the high te...

  6. ESTIMATION OF INDUCED CURRENTS IN THE SHIELDS OF ELECTRICAL POWER CABLES WITH XLPE INSULATION

    Directory of Open Access Journals (Sweden)

    I. V. Oleksyuk

    2015-01-01

    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.

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

    OpenAIRE

    Chenmeng Xiang; Quan Zhou; Jian Li; Qingdan Huang; Haoyong Song; Zhaotao Zhang

    2016-01-01

    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...

  8. Investigation of electrical responses to acupuncture stimulation: the effect of electrical grounding and insulation conditions.

    Science.gov (United States)

    Lee, Yong-Heum; Ryu, Yeon-Hang; Jung, Byungjo

    2009-03-01

    Acupuncture in Oriental medicine has been widely used as a core therapeutic method due to its minimal side-effects and therapeutic efficacy. However, the electrical response to acupuncture stimulation (ERAS) has not been clearly studied under acupuncture conditions that might affect the efficacy of acupuncture therapy. In this study, the ERAS was objectively investigated by measuring meridian electric potentials (MEPs) when the electrical grounding conditions of the operator and subject were varied, and when the insulation conditions of acupuncture needle were varied. MEPs between Sang-geoheo (ST37) and Ha-geoheo (ST39) of the Stomach Meridian (ST) were measured by stimulating Jok-samni (ST36) with an acupuncture needle. For non-insulated acupuncture stimulation (NIAS), the average MEP peak was 148.6 +/- 20.6 when neither the operator nor the subject were electrically grounded, 23.1 +/- 8.8 when the subject only was electrically grounded, 348 +/- 76.8 when the operator only was electrically grounded, and 19.9 +/- 4.7 when both the operator and the subject were electrically grounded. The MEPs presented various magnitudes and patterns depending on the electrical grounding conditions. The MEP pattern was very similar to that of the charge and discharge of a capacitor. For insulated acupuncture stimulation (IAS), the average MEP peak was 20 +/- 4 in all electrical grounding conditions, which is not a significant electric response for acupuncture stimulation. In terms of electricity, this study verified that acupuncture therapy might be affected by acupuncture conditions such as (1) the electrical grounding condition of the operator and the subject and (2) the insulation condition of the acupuncture needle.

  9. Electrically Induced Multiple Metal-Insulator Transitions in Oxide Nanodevices

    Science.gov (United States)

    del Valle, Javier; Kalcheim, Yoav; Trastoy, Juan; Charnukha, Aliaksei; Basov, Dimitri N.; Schuller, Ivan K.

    2017-11-01

    We show that electrical resistive switching can trigger the appearance of multiple metal-insulator transitions (MITs) in VO2 and V2O3 planar nanodevices. We have fabricated planar devices to electrically induce oxygen vacancy drift and filament formation. We show that oxygen migration can create ordered vanadium-oxide phases of varying stoichiometry with an intrinsic MIT, resulting in well-defined hysteresis loops in the R vs T characteristics of the device. We also show that oxygen migration induces oxide phases displaying correlated behaviors. Our results open up the possibility to electrically control the MIT, enabling alternative functionalities in memristive devices and allowing for alternative paradigms in neuromorphic computing or memory applications.

  10. Effects of RTV coating on the electrical performance of polymer insulator under lightning impulse voltage condition.

    Directory of Open Access Journals (Sweden)

    Farah Adilah Jamaludin

    Full Text Available Located near the equator, Malaysia is a country with one of the highest lightning densities in the world. Lightning contributes to 70% of the power outages in Malaysia and affects power equipment, automated network systems, causes data losses and monetary losses in the nation. Therefore, consideration of insulator evaluation under lightning impulses can be crucial to evaluate and attempt to overcome this issue. This paper presents a new approach to increase the electrical performance of polymer insulators using a Room Temperature Vulcanisation (RTV coating. The evaluation involves three different settings of polymer insulator, namely uncoated, RTV type 1, and RTV type 2 upper surface coatings. All the insulators were tested under three different conditions as dry, clean wet and salty under different impulse polarities using the even-rising test method. The voltage breakdown for each test was recorded. From the experiment, it was found that the effectiveness of the RTV coating application became apparent when tested under salty or polluted conditions. It increased the voltage withstand capabilities of the polymer insulator up to 50% from the basic uncoated insulator. Under dry and clean conditions, the RTV coating provided just a slight increase of the breakdown voltage. The increase in voltage breakdown capability decreased the probability of surface discharge and dry band arcing that could cause degradation of the polymeric material housing. The RTV type 1 coating was found to be more effective when performing under a lightning impulse. The findings might help the utility companies improve the performance of their insulators in order to increase power system reliability.

  11. Effects of RTV coating on the electrical performance of polymer insulator under lightning impulse voltage condition.

    Science.gov (United States)

    Jamaludin, Farah Adilah; Ab-Kadir, Mohd Zainal Abidin; Izadi, Mahdi; Azis, Norhafiz; Jasni, Jasronita; Abd-Rahman, Muhammad Syahmi

    2017-01-01

    Located near the equator, Malaysia is a country with one of the highest lightning densities in the world. Lightning contributes to 70% of the power outages in Malaysia and affects power equipment, automated network systems, causes data losses and monetary losses in the nation. Therefore, consideration of insulator evaluation under lightning impulses can be crucial to evaluate and attempt to overcome this issue. This paper presents a new approach to increase the electrical performance of polymer insulators using a Room Temperature Vulcanisation (RTV) coating. The evaluation involves three different settings of polymer insulator, namely uncoated, RTV type 1, and RTV type 2 upper surface coatings. All the insulators were tested under three different conditions as dry, clean wet and salty under different impulse polarities using the even-rising test method. The voltage breakdown for each test was recorded. From the experiment, it was found that the effectiveness of the RTV coating application became apparent when tested under salty or polluted conditions. It increased the voltage withstand capabilities of the polymer insulator up to 50% from the basic uncoated insulator. Under dry and clean conditions, the RTV coating provided just a slight increase of the breakdown voltage. The increase in voltage breakdown capability decreased the probability of surface discharge and dry band arcing that could cause degradation of the polymeric material housing. The RTV type 1 coating was found to be more effective when performing under a lightning impulse. The findings might help the utility companies improve the performance of their insulators in order to increase power system reliability.

  12. Effects of RTV coating on the electrical performance of polymer insulator under lightning impulse voltage condition

    Science.gov (United States)

    Jamaludin, Farah Adilah; Ab-Kadir, Mohd Zainal Abidin; Izadi, Mahdi; Azis, Norhafiz; Jasni, Jasronita; Abd-Rahman, Muhammad Syahmi

    2017-01-01

    Located near the equator, Malaysia is a country with one of the highest lightning densities in the world. Lightning contributes to 70% of the power outages in Malaysia and affects power equipment, automated network systems, causes data losses and monetary losses in the nation. Therefore, consideration of insulator evaluation under lightning impulses can be crucial to evaluate and attempt to overcome this issue. This paper presents a new approach to increase the electrical performance of polymer insulators using a Room Temperature Vulcanisation (RTV) coating. The evaluation involves three different settings of polymer insulator, namely uncoated, RTV type 1, and RTV type 2 upper surface coatings. All the insulators were tested under three different conditions as dry, clean wet and salty under different impulse polarities using the even-rising test method. The voltage breakdown for each test was recorded. From the experiment, it was found that the effectiveness of the RTV coating application became apparent when tested under salty or polluted conditions. It increased the voltage withstand capabilities of the polymer insulator up to 50% from the basic uncoated insulator. Under dry and clean conditions, the RTV coating provided just a slight increase of the breakdown voltage. The increase in voltage breakdown capability decreased the probability of surface discharge and dry band arcing that could cause degradation of the polymeric material housing. The RTV type 1 coating was found to be more effective when performing under a lightning impulse. The findings might help the utility companies improve the performance of their insulators in order to increase power system reliability. PMID:29136025

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

    Science.gov (United States)

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

    2017-06-01

    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. Electric-field-induced antiferromagnetic resonance in antiferromagnetic insulators with spin-orbit coupling

    Directory of Open Access Journals (Sweden)

    Akihiko Sekine

    2017-05-01

    Full Text Available We study theoretically spin dynamics in three-dimensional antiferromagnetic insulators with spin-orbit coupling. We focus on the antiferromagnetic insulators whose low-energy effective model possesses a topological term called the θ term. By solving the Landau-Lifshitz-Gilbert equation in the presence of the θ term, we show that the antiferromagnetic resonance can be realized by ac electric fields along with static magnetic fields. The antiferromagnetic resonance can be detected via the spin pumping from the Néel field and net magnetization. We calculate both contributions to the pumped spin current, and find that the magnitude of the ac electric field to cause the resonance state is very small (∼ 1 V/m. This indicates that spin currents can be generated efficiently. The mechanism of the antiferromagnetic resonance in this study is understood as the inverse process of the dynamical chiral magnetic effect.

  15. Cloaking magnetic field and generating electric field with topological insulator and superconductor bi-layer sphere

    Directory of Open Access Journals (Sweden)

    Jin Xu

    2017-12-01

    Full Text Available When an electric field is applied on a topological insulator, not only the electric field is generated, but also the magnetic field is generated, vice versa. I designed topological insulator and superconductor bi-layer magnetic cloak, derived the electric field and magnetic field inside and outside the topological insulator and superconductor sphere. Simulation and calculation results show that the applied magnetic field is screened by the topological insulator and superconductor bi-layer, and the electric field is generated in the cloaked region.

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

    Science.gov (United States)

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

    2008-10-01

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

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

    Energy Technology Data Exchange (ETDEWEB)

    Hara, Masanori; Suehiro, Junya; Shigematsu, Hidetaka; Yano, Shinsuke (Kyushu Univ., Faculty of Engineering, Fukuoka, (Japan))

    1989-09-20

    When a transverse magnetic field is applied to an insulating system in vacuum, its dielectric strength deteriorates considerably and this breaking characteristic is considered to be caused by generation of impact ionization between the atoms of residual gas and electrons due to the cycloid movements of the latter. In this study, taking the above breaking mechanism into consideration, proposed were methods using a spiral spacer and an electric field control electrode as the methods of improving dielectric strength in vacuum of the cryogenic equipment generating such a strong magnetic field as superconducting magnet, etc.. Concerning the former method in case when a spiral pitch is infinitive and the latter method in case when a grounding electrode is installed in the neighborhood of the inside electrode, the respective effectiveness was demonstrated by experiments. In other words, with regard to the coaxial cylindrical electrode system, in case when no method of improving electrical insulation was applied, the breaking voltage decreased from about 20kV to about 1kV as the transverse magnetic field was made stronger, but in case when a spacer was used, the decline of electrical insulation could be suppressed within several kV up to the magnetic field of 4.65T and the magnetic field at which the decline of the breaking voltage started was increased three times by using a control electrode. 7 refs., 14 figs.

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

    Energy Technology Data Exchange (ETDEWEB)

    Sukhanov, Aleksei A.

    2017-05-15

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

  19. Electrical detection of spin-momentum locking in topological insulators

    Science.gov (United States)

    Li, Connie; van't Erve, Olaf; Robinson, Jeremy; Li, Yaoyi; Li, Lian; Jonker, Berry

    2015-03-01

    One of the most striking properties of topological insulators (TIs) is that of spin-momentum locking - the spin of the TI surface state lies in-plane, and is locked at right angle to the carrier momentum. While anticipated by theory, direct electrical access to this spin system in a simple transport structure had been challenging, due to that the bulk is typically unintentionally doped and contributes to transport. Using a ferromagnet/tunnel barrier detector contact that preferentially probes surface/interface spins, we have demonstrated the first direct electrical detection of spin-momentum locking in the TI surface states in MBE-grown Bi2Se3. However, as the bulk carrier concentration for Bi2Se3 is typically in the 1019/cm3 range, the Fermi level is well within the conduction band, where a significant portion of the current is shunted through the bulk. Moving the Fermi level to within the gap is desirable to eliminate current shunting, as well as contribution from Rashba 2DEG states that may dilute the signal. These results, as well as how they affect the spin signal measured will be discussed at the meeting. Supported by NRL core funds and Nanoscience Institute.

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

    CERN Document Server

    Diesendorf, W

    2015-01-01

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

  1. Research on High Temperature Ceramic Insulation for Electrical Conductors

    Science.gov (United States)

    Kreidler, Eric R.; Bhallamudi, Vidya Praveen

    2001-01-01

    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.

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

    CERN Document Server

    Meuris, C; Leroy, D; Szeless, Balázs

    1999-01-01

    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...

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

    Directory of Open Access Journals (Sweden)

    H. E. Rojas

    2015-11-01

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

  4. Consideration in GIS insulation coordination

    Energy Technology Data Exchange (ETDEWEB)

    Bargigia, A.

    1990-01-01

    Analysis of electrical system failures reveals that many are caused by insulation breakdowns due to overvoltages. The problem of insulation co-ordination is then one of the most important aspects in the design of an electrical system. Insulation co-ordination of gas-insulated sub-stations (GIS) has recently received much attention especially due to a large diffusion of this insulation technique. In this review of GIS insulation co-ordination, attention is given to the impact on the insulation co-ordination strategy of the metal-clad disconnector performance during capacity current switching operations.

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

    Directory of Open Access Journals (Sweden)

    T. Watkins

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

  6. Effect of pollutant gases on electrical insulators deterioration

    Directory of Open Access Journals (Sweden)

    Zamarad, A.

    2000-06-01

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

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

  7. Ceramics Porcelain Based Electric Solid Insulator Using Local Raw Materials

    Directory of Open Access Journals (Sweden)

    Eva Indiani

    2009-08-01

    Full Text Available AbstractElectric solid insulator based on ceramics porcelain had been made by using local raw materials: 68% feldspar, 10% kaolinite and 22% quartz, and also added 0%, 5%, 10%, 15%, 20%, 25% cullet (From total mass. The forming process of the porcelain was conducted by milling the raw materials using ball mill and screened using 200 mesh screening. The samples were formed by using the dry-press method with the pressure of 50MPa, then the samples is sintered at temperature of 1000oC, 1050oC, 1100oC, 1150oC for 2 hours. The properties of the samples had been analyzed for their shrinkage, density, bending strength and resistivity. The result of the experiment showed that the optimum value was reached by ceramic which was added by 15% cullet and sintered at temperature of 1100oC. This ceramic had shrinkage of 9,70%, density of 2,44 g/cm3, bending strength of 86,73 MPa and the resistivity at 25oC is 2,32x108 Ωcm.

  8. Development of electrically insulating CaO coatings

    Energy Technology Data Exchange (ETDEWEB)

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

    1998-09-01

    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.

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

    Science.gov (United States)

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

    2015-05-07

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

  10. Insulation Resistance Monitoring Algorithm for Battery Pack in Electric Vehicle Based on Extended Kalman Filtering

    National Research Council Canada - National Science Library

    Chuanxue Song; Yulong Shao; Shixin Song; Silun Peng; Fang Zhou; Cheng Chang; Da Wang

    2017-01-01

    To improve the accuracy of insulation monitoring between the battery pack and chassis of electric vehicles, we established a serial battery pack model composed of first-order resistor-capacitor (RC...

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

    Directory of Open Access Journals (Sweden)

    Chenmeng Xiang

    2016-04-01

    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.

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

    Science.gov (United States)

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

    2016-07-01

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

  13. High Temperature Electrical Insulation Materials for Space Applications Project

    Data.gov (United States)

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

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2015-10-15

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

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

    OpenAIRE

    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.

    2015-01-01

    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 FET ...

  16. Electrical Trees in a Composite Insulating System Consisted of Epoxy Resin and Mica: The Case of Multiple Mica Sheets For Machine Insulation

    Directory of Open Access Journals (Sweden)

    V. A. Kioussis

    2014-08-01

    Full Text Available Epoxy resin and mica sheets consist the essential insulation of rotating machine stator bars. Such an insulation, although very resistant to partial discharges, is subjected to considerable electrical stresses and consequently electrical trees may ensue. In this paper, an effort is made to simulate electrical tree propagation in multiple epoxy resin/mica sheets with the aid of Cellular Automata (CA. An attempt to compare the simulation results with experimental results is also made.

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

    Directory of Open Access Journals (Sweden)

    Milan Spohner

    2012-01-01

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

  18. Electrical resistance of individual defects at a topological insulator surface

    Science.gov (United States)

    Lüpke, Felix; Eschbach, Markus; Heider, Tristan; Lanius, Martin; Schüffelgen, Peter; Rosenbach, Daniel; von den Driesch, Nils; Cherepanov, Vasily; Mussler, Gregor; Plucinski, Lukasz; Grützmacher, Detlev; Schneider, Claus M.; Voigtländer, Bert

    2017-06-01

    Three-dimensional topological insulators host surface states with linear dispersion, which manifest as a Dirac cone. Nanoscale transport measurements provide direct access to the transport properties of the Dirac cone in real space and allow the detailed investigation of charge carrier scattering. Here we use scanning tunnelling potentiometry to analyse the resistance of different kinds of defects at the surface of a (Bi0.53Sb0.47)2Te3 topological insulator thin film. We find the largest localized voltage drop to be located at domain boundaries in the topological insulator film, with a resistivity about four times higher than that of a step edge. Furthermore, we resolve resistivity dipoles located around nanoscale voids in the sample surface. The influence of such defects on the resistance of the topological surface state is analysed by means of a resistor network model. The effect resulting from the voids is found to be small compared with the other defects.

  19. Insulation Resistance Monitoring Algorithm for Battery Pack in Electric Vehicle Based on Extended Kalman Filtering

    OpenAIRE

    Chuanxue Song; Yulong Shao; Shixin Song; Silun Peng; Fang Zhou; Cheng Chang; Da Wang

    2017-01-01

    To improve the accuracy of insulation monitoring between the battery pack and chassis of electric vehicles, we established a serial battery pack model composed of first-order resistor-capacitor (RC) circuit battery cells. We then designed a low-voltage, low-frequency insulation monitoring model based on this serial battery pack model. An extended Kalman filter (EKF) was designed for this non-linear system to filter the measured results, thus mitigating the influence of noise. Experimental and...

  20. Insulation Resistance Monitoring Algorithm for Battery Pack in Electric Vehicle Based on Extended Kalman Filtering

    Directory of Open Access Journals (Sweden)

    Chuanxue Song

    2017-05-01

    Full Text Available To improve the accuracy of insulation monitoring between the battery pack and chassis of electric vehicles, we established a serial battery pack model composed of first-order resistor-capacitor (RC circuit battery cells. We then designed a low-voltage, low-frequency insulation monitoring model based on this serial battery pack model. An extended Kalman filter (EKF was designed for this non-linear system to filter the measured results, thus mitigating the influence of noise. Experimental and simulation results show that the proposed monitoring model and extended Kalman filtering algorithm for insulation resistance monitoring present satisfactory estimation accuracy and robustness.

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

    Directory of Open Access Journals (Sweden)

    Mihaela Răduca

    2009-10-01

    Full Text Available Abstract. This paper present a mathematical model of lifetime duration at hydro generator stator winding insulation when at hydro generator can be appear the damage regimes. The estimation to make by take of the programming and non-programming revisions, through the introduction and correlation of the new defined notions.

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

    Science.gov (United States)

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

    2017-08-01

    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.

  3. Studies on electrical cable insulation for nuclear applications

    Energy Technology Data Exchange (ETDEWEB)

    Lee, B.S.; Soo, P.; MacKenzie, D.R. [Brookhaven National Lab., Upton, NY (USA); Blackburn, P. [Beloit Junior-Senior High School, KS (USA)

    1989-12-01

    Two new polyethylene cable insulations have been formulated for nuclear applications, and have been tested under gamma radiation. Both insulations are based on low density polyethylene, one with PbO and the other with Sb{sub 2}O{sub 3} as additives. The test results show that the concept of using inorganic anti-oxidants to retard radiation initiated oxidation is viable, and PbO is more effective than Sb{sub 2}O{sub 3} in slowing down radiation initiated oxidation (RIO). Also, radiation degradation data for polyethylene and polyvinyl chloride at 60{degrees}C have been generated, which will be used to understand radiation initiated oxidation process on these materials combined with the 25{degrees}C data that will be generated in the future. 14 refs., 41 figs., 3 tabs.

  4. Effect on superhydrophobic surfaces on electrical porcelain insulator, improved technique at polluted areas for longer life and reliability

    OpenAIRE

    Isaac Ramalla; Rajeev K Gupta; Kamal Bansal

    2015-01-01

    This paper proposes a novel technique to enhance the stability of high-voltage insulators, which are affected due to the presence of dust, contamination, electrical stresses in a high moisture content environment. These result in puncture of insulators and heavy loss due to power outages in the transmission lines. To extend its stability, powdered coating is done on the insulators which have insulation property and super hydrophobicity. In this paper, the authors were inspired by the ‘lotus e...

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

    DEFF Research Database (Denmark)

    Lizzit, Silvano; Larciprete, Rosanna; Lacovig, Paolo

    2012-01-01

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

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

    Directory of Open Access Journals (Sweden)

    Herbert Enrique Rojas Cubides

    2015-06-01

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

  7. Electrically induced insulator to metal transition in epitaxial SmNiO{sub 3} thin films

    Energy Technology Data Exchange (ETDEWEB)

    Shukla, Nikhil, E-mail: nss152@psu.edu; Dasgupta, Sandeepan; Datta, Suman [Department of Electrical Engineering, The Pennsylvania State University, University Park, Pennsylvania 16802 (United States); Joshi, Toyanath; Borisov, Pavel; Lederman, David [Department of Physics and Astronomy, West Virginia University, Morgantown, West Virginia 26506-6315 (United States)

    2014-07-07

    We report on the electrically induced insulator to metal transition (IMT) in SmNiO{sub 3} thin films grown on (001) LaAlO{sub 3} by pulsed laser deposition. The behavior of the resistivity as a function of temperature suggests that the primary transport mechanism in the SmNiO{sub 3} insulating state is dominated by Efros-Shklovskii variable range hopping (ES-VRH). Additionally, the magnetic transition in the insulating state of SmNiO{sub 3} modifies the characteristics of the ES-VRH transport. Systematic DC and pulsed current-voltage measurements indicate that current-induced joule heating is the fundamental mechanism driving the electrically induced IMT in SmNiO{sub 3}. These transport properties are explained in context of the IMT in SmNiO{sub 3} being related to the strong electron-lattice coupling.

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

    Directory of Open Access Journals (Sweden)

    Ziang Jing

    2016-08-01

    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.

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

    Science.gov (United States)

    Jing, Ziang; Li, Changming; Zhao, Hong; Zhang, Guiling; Han, Baozhong

    2016-08-10

    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.

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

    Directory of Open Access Journals (Sweden)

    Boudou L.

    2010-06-01

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

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

    Directory of Open Access Journals (Sweden)

    Altafim Ruy Alberto Corrêa

    2003-01-01

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

  12. GASSING OF THE ELECTRICAL INSULATING FLUIDS - A DETERMINANT FACTOR OF THE TRANSFORMERS SAFETY IN OPERATION

    Directory of Open Access Journals (Sweden)

    VOINA A.

    2017-06-01

    Full Text Available The influence on the quality of the electrical insulating fluids on the safety in operation of the transformers has been evaluated. After processing the comparative experimental data obtained by gas chromatography technique on 5 different sorts of electrical insulating fluids (a sort of vegetable oil with high oleic content and with addition of 0.5% antioxidant "functional model" - compared with two commercial sorts of mineral oil, 1 mainly vegetable commercial oil, 1 commercial synthetic ester, thermal aged in contact with electrical insulating paper and copper for electrical use, at 110 ± 3 °C for 1000 hours in closed vessels (limited access to atmospheric oxygen it has been found that at the transformers filled with mineral oils, the risk of explosion and fire is approx. 10 times higher than those filled with synthetic or vegetal ester. It has also been found that the ageing of the insulation paper is approx. 15 times slower in the synthetic and natural ester than in the mineral oils normally used in transformers.

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

    DEFF Research Database (Denmark)

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

    2009-01-01

    A fabrication process for monolithic integration of vertically aligned carbon nanotubes in electrically insulated microfluidic channels is presented. A 150 nm thick amorphous silicon layer could be used both for anodic bonding of a glass lid to hermetically seal the microfluidic glass channels...

  14. Modeling, Fabrication, and Electrical Testing of Metal-Insulator-Metal Diode

    Science.gov (United States)

    2011-12-01

    Horizon: Optical Rectenna Solar Cell; NREL/SR-520-33263; NREL, August 2011. [4] Simmons, J. G. Generalized Formula for the Electric Tunnel Effect between...K. Design and Develop- ment of Batch Fabricatable Metal-Insulator-Metal Diode and Microstrip Slot Antenna as Rectenna Elements. Sensors and

  15. Electrical treeing in ceramic-based insulating materials (Ba TiO3 ...

    African Journals Online (AJOL)

    Electrical treeing in ceramic-based insulating materials (Ba TiO3 – SiO2). ... It was observed that the tree-like structures were of two types and that the initiation could have been due to partial discharges that arose from microcracks, pores and other similar defects. This equally shows that the mechanism of the initiation of an ...

  16. An Explosively Actuated Electrical Switch Using Kapton Insulation

    Science.gov (United States)

    1993-03-01

    would also like to thank our colleagues who made valuable contributions to the experimental effort: Robert Hay, Nathaniel Snowden , and Bernard... Snowden . The authors are grateful to J. Forbes who made many valuable comments on this manuscript. Approved by: KURT F. MUELLER, Head Warheads and...field; see Figure l-l(B). 1-1 NSWCDD/TR-92/124 Electrodes Shock Front Electric Field Kaptori Film Electrodes, Shock Front El Electric

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

    Directory of Open Access Journals (Sweden)

    Yun Chen

    2017-10-01

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

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

    DEFF Research Database (Denmark)

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

    2011-01-01

    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...

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

    Science.gov (United States)

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

    2017-09-01

    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.

  20. Remarkably improved electrical insulating performances of lightweight polypropylene nanocomposites with fullerene

    Science.gov (United States)

    Dang, Bin; Hu, Jun; Zhou, Yao; He, Jinliang

    2017-11-01

    A polypropylene/fullerene nanocomposite was fabricated via solution processing with good dispersion of the fullerene nanoparticles. It was observed that a small amount of fullerene (~1 wt. ‰) can significantly improve the direct current (DC) electrical insulation performance (i.e. improved space charge distribution, greater DC dielectric breakdown strength, and larger DC volume resistivity) of polypropylene. Thermally stimulated depolarization current tests indicate that fullerene doping remarkably increases the deep trap density of pure polypropylene. The mechanisms by which the electrical properties of the polypropylene nanocomposites were improved are the introduction of deep traps and the high electron affinity of fullerene. The deep traps result from the interfaces between polypropylene and fullerene. This work provides a potential method to tailor lightweight nanodielectric materials with excellent electrical insulating performances.

  1. Insulator-metal transitions induced by electric field and photoirradiation in organic Mott insulator deuterated κ-(BEDT-TTF)2Cu[N(CN)2]Br.

    Science.gov (United States)

    Sabeth, Farzana; Iimori, Toshifumi; Ohta, Nobuhiro

    2012-04-25

    The Mott insulator-metal transition induced by an external stimulus such as electric field, pressure, chemical doping, or photoirradiation has received considerable attention because of the potential use in new optoelectronic functional devices. Here we report an abrupt Mott insulator-metal transition observed as a current jump in a molecular-based Mott insulator, namely, deuterated κ-(BEDT-TTF)(2)Cu[N(CN)(2)]Br, where BEDT-TTF = bis(ethylenedithio)tetrathiafulvalene, upon application of a pulsed voltage of certain magnitude (threshold voltage). Furthermore, the threshold voltage needed for the transition is shown to be reduced by photoirradiation. Thus, the Mott insulator-metal transition can be controlled by a combination of an external electric field and photoirradiation.

  2. Cooling of electrically insulated high voltage electrodes down to 30 mK

    CERN Document Server

    Eisel, T; Burghart, G; Feigl, S; Haug, F; Koettig, T

    2011-01-01

    AEgIS [1] is an antimatter experiment, using high voltage electrodes at 100 mK. In this work two possible principles to cool these electrodes with a dilution refrigerator are described: the Rod and the Sandwich. The metallic Rod is electrically insulated by a ceramic and connects a single electrode directly with a heat exchanger placed in the mixing chamber. The Sandwich consists of an elec-trically insulating sapphire plate, at both sides covered with indium. The total thermal resistivities of the Rod and of different Sandwich samples are measured between (30 and 130) mK. The lowest resistivity of the Sandwich is achieved with indium vapour deposited on polished sapphire (26 cm2K4/W at 30 mK). The resistivity of the Rod is significantly lower (0.5 cm2K4/W at 30 mK).

  3. THE INSULATION PROBLEMS ON PORCELAIN INSULATORS

    Directory of Open Access Journals (Sweden)

    Engin ÇETİN

    2005-02-01

    Full Text Available Porcelain insulators used on electrical institutions are important materials to provide system reliability and material insulation. Specification of raw materials of insulators and environmental factors affect insulator strength and operation. In this study, environmental factors and materials used on porcelain insulator manufacturing are examined and also their influence on system reliability and insulation are investigated.

  4. THE INSULATION PROBLEMS ON PORCELAIN INSULATORS

    OpenAIRE

    Engin ÇETİN; N. Lerzan ÖZER; ÇETİN, Meriç

    2005-01-01

    Porcelain insulators used on electrical institutions are important materials to provide system reliability and material insulation. Specification of raw materials of insulators and environmental factors affect insulator strength and operation. In this study, environmental factors and materials used on porcelain insulator manufacturing are examined and also their influence on system reliability and insulation are investigated.

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

    KAUST Repository

    Jin, Young Kyu

    2010-11-01

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

  6. Methyltrimethoxysilane-insulated piezoelectric microcantilevers for direct, all-electrical biodetection in buffered aqueous solutions

    Science.gov (United States)

    Capobianco, Joseph A.; Shih, Wan Y.; Shih, Wei-Heng

    2006-12-01

    We have examined coating (PbMg1/3Nb2/3O3)0.63-(PbTiO3)0.37 (PMN-PT)/tin piezoelectric microcantilever sensors (PEMSs) with a thin methyltrimethoxysilane (MTMS) by a simple solution method to electrically insulate the PEMS for biodetection in phosphate buffered saline (PBS) solutions. The PMN-PT/tin PEMSs were constructed using PMN-PT freestanding films that exhibited an electric-field-enhanced giant piezoelectric coefficient. The insulation procedure involved spin coatings of MTMS followed by cross-linking in water, which yielded a coating layer of about 10nm in thickness on the tin side of the PEMS. We showed that the MTMS-insulated PMN-PT/tin PEMSs were capable of electrical self-excitation and self-sensing with a stable resonance spectrum exhibiting a quality factor of Q =50 when submerged in 0.1M PBS solution. Direct, all-electrical, in situ detection of Escherichia coli O157:H7 at various concentrations was demonstrated at a flow rate of 0.5ml/min. A MTMS-insulated PMN-PT/tin PEMS 725μm long consisting of a 22-μm-thick PMN-PT layer and a 6-μm-thick tin layer exhibited a mass detection sensitivity Δm /Δf=-3±2×10-12g/Hz and a concentration sensitivity of better than 100cells/ml in less than 1ml of liquid.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2007-12-15

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

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

    KAUST Repository

    Lim, Seung Jae

    2014-12-30

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

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2011-07-01

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

  10. HEAT TRANSFER THROUGH CYANATE ESTER EPOXY MIX AND EPOXY GPAP–DETDA ELECTRICAL INSULATIONS AT SUPERFLUID HELIUM TEMPERATURE

    CERN Document Server

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

    2011-01-01

    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.

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

    Science.gov (United States)

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

    2016-09-01

    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.

  12. Reaction and Protection of Electrical Wire Insulators in Atomic-oxygen Environments

    Science.gov (United States)

    Hung, Ching-Cheh; Cantrell, Gidget

    1994-01-01

    Atomic-oxygen erosion on spacecraft in low Earth orbit is an issue which is becoming increasingly important because of the growing number of spacecraft that will fly in the orbits which have high concentrations of atomic oxygen. In this investigation, the atomic-oxygen durability of three types of electrical wire insulation (carbon-based, fluoropolymer, and polysiloxane elastomer) were evaluated. These insulation materials were exposed to thermal-energy atomic oxygen, which was obtained by RF excitation of air at a pressure of 11-20 Pa. The effects of atomic-oxygen exposure on insulation materials indicate that all carbon-based materials erode at about the same rate as polyamide Kapton and, therefore, are not atomic-oxygen durable. However, the durability of fluoropolymers needs to be evaluated on a case by case basis because the erosion rates of fluoropolymers vary widely. For example, experimental data suggest the formation of atomic fluorine during atomic-oxygen amorphous-fluorocarbon reactions. Dimethyl polysiloxanes (silicone) do not lose mass during atomic-oxygen exposure, but develop silica surfaces which are under tension and frequently crack as a result of loss of methyl groups. However, if the silicone sample surfaces were properly pretreated to provide a certain roughness, atomic oxygen exposure resulted in a sturdy, non-cracked atomic-oxygen durable SiO2 layer. Since the surface does not crack during such silicone-atomic oxygen reaction, the crack-induced contamination by silicone can be reduced or completely stopped. Therefore, with proper pretreatment, silicone can be either a wire insulation material or a coating on wire insulation materials to provide atomic-oxygen durability.

  13. Proliferation of metallic domains caused by inhomogeneous heating near the electrically-driven transition in VO$_2$ nanobeams

    OpenAIRE

    Singh, Sujay; Horrocks, Gregory; Marley, Peter M; Shi, Zhenzhong; Banerjee, Sarbajit; Sambandamurthy, G.

    2015-01-01

    We discuss the mechanisms behind the electrically driven insulator-metal transition in single crystalline VO$_2$ nanobeams. Our DC and AC transport measurements and the versatile harmonic analysis method employed show that non-uniform Joule heating causes phase inhomogeneities to develop within the nanobeam and is responsible for driving the transition in VO$_{2}$. A Poole-Frenkel like purely electric field induced transition is found to be absent and the role of percolation near and away fro...

  14. Mechanically Stretchable and Electrically Insulating Thermal Elastomer Composite by Liquid Alloy Droplet Embedment

    Science.gov (United States)

    Jeong, Seung Hee; Chen, Si; Huo, Jinxing; Gamstedt, Erik Kristofer; Liu, Johan; Zhang, Shi-Li; Zhang, Zhi-Bin; Hjort, Klas; Wu, Zhigang

    2015-01-01

    Stretchable electronics and soft robotics have shown unsurpassed features, inheriting remarkable functions from stretchable and soft materials. Electrically conductive and mechanically stretchable materials based on composites have been widely studied for stretchable electronics as electrical conductors using various combinations of materials. However, thermally tunable and stretchable materials, which have high potential in soft and stretchable thermal devices as interface or packaging materials, have not been sufficiently studied. Here, a mechanically stretchable and electrically insulating thermal elastomer composite is demonstrated, which can be easily processed for device fabrication. A liquid alloy is embedded as liquid droplet fillers in an elastomer matrix to achieve softness and stretchability. This new elastomer composite is expected useful to enhance thermal response or efficiency of soft and stretchable thermal devices or systems. The thermal elastomer composites demonstrate advantages such as thermal interface and packaging layers with thermal shrink films in transient and steady-state cases and a stretchable temperature sensor. PMID:26671673

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

    Science.gov (United States)

    Tan, J. K.; Abas, N.

    2017-07-01

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

  16. An innovative hybrid insulation switch to enable/disable electrical loads without overvoltages

    Science.gov (United States)

    Zajkowski, Konrad

    2017-10-01

    This article describes an innovative project for the design of a low voltage switch to enable/disable electrical devices from an AC source, which is characterised by the absence of arc ignition. When powered off, this device is a galvanically separated of the receiver from the power source. The proposed hybrid interaction has two switches: the insulating switch made of mechanical contacts and the current switch made of elements from power electronics. The absence of arc ignition increases the equipment uptime and improves the comfort-powered receiver and equipment located nearby.

  17. Electrical control of the superconducting-to-insulating transition in graphene-metal hybrids.

    Science.gov (United States)

    Allain, Adrien; Han, Zheng; Bouchiat, Vincent

    2012-05-20

    Graphene is a sturdy and chemically inert material exhibiting an exposed two-dimensional electron gas of high mobility. These combined properties enable the design of graphene composites, based either on covalent or non-covalent coupling of adsorbates, or on stacked and multilayered heterostructures. These systems have shown tunable electronic properties such as bandgap engineering, reversible metal-insulating transition or supramolecular spintronics. Tunable superconductivity is expected as well, but experimental realization is lacking. Here, we show experiments based on metal-graphene hybrid composites, enabling the tunable proximity coupling of an array of superconducting nanoparticles of tin onto a macroscopic graphene sheet. This material allows full electrical control of the superconductivity down to a strongly insulating state at low temperature. The observed gate control of superconductivity results from the combination of a proximity-induced superconductivity generated by the metallic nanoparticle array with the two-dimensional and tunable metallicity of graphene. The resulting hybrid material behaves, as a whole, like a granular superconductor showing universal transition threshold and localization of Cooper pairs in the insulating phase. This experiment sheds light on the emergence of superconductivity in inhomogeneous superconductors, and more generally, it demonstrates the potential of graphene as a versatile building block for the realization of superconducting materials.

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

    Directory of Open Access Journals (Sweden)

    E. Mihailov

    2016-07-01

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

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

    Directory of Open Access Journals (Sweden)

    Yunbo Ou

    2016-08-01

    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.

  20. Effect of thickness of insulation coating on temperature of electrically exploded tungsten wires in vacuum

    Science.gov (United States)

    Shi, Huantong; Zou, Xiaobing; Wang, Xinxin

    2017-07-01

    This paper reports an interesting observation of great differences in the temperature of exploded wires with insulation coating of different thicknesses. Two kinds of polyimide-coated tungsten wires were used with the same conductive diameter 12.5 μm but a different thickness of coating, 0.75-2.25 μm and 2.25-4.25 μm, respectively. The specific energy reconstructed from the current and voltage signals was quite close for the tested wires. However, the exploding scenario, obtained from Mach-Zehnder interferograms, showed great differences: a neutral outer-layer was observed around the thick-coated wire, which was absent for the thin-coated wire; and the calculated electron density and local thermal equilibrium temperature were much higher for thick-coated wires. The heat-preserving neutral layer formed by the decomposition of the insulation was supposed to be the cause of this phenomenon.

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

    Science.gov (United States)

    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

    2016-04-01

    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.

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

    Science.gov (United States)

    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.

    2016-04-01

    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.

  3. Evolution of the electric potential of an insulator under charged particle impact

    Science.gov (United States)

    Giglio, E.; Guillous, S.; Cassimi, A.; Zhang, H. Q.; Nagy, G. U. L.; Tőkési, K.

    2017-03-01

    Insulating glass capillaries have been shown to lead to ion transmission without any change in either the ion charge state or in the ion kinetic energy. This surprising process has been attributed to a self-organized distribution of charge patches creating the necessary guiding electric potential on the capillary walls. By the use of our original electrometer, it has been possible to measure and monitor simultaneously and in a nondestructive way the electric potential and the transmitted beam intensity during the charging up by an Ar+ ion beam. We show that glass microcapillaries can reach potentials higher than 500 V, even in the case of singly charged ions, opening the possibility of high transmission rates and providing a renewed sight into ion beam transport by tapered capillaries. The setup, also suitable for the determination of leakage currents governing the capillary potential dynamics, allowed one to evidence that secondary electrons may strongly affect the rise of the capillary potential and consequently avoid Coulomb blocking of the beam transmission across insulating capillaries.

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

    Science.gov (United States)

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

    2017-03-01

    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.

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

    Science.gov (United States)

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

    2017-10-01

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

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

    Science.gov (United States)

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

    2018-01-01

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

  7. A Fast-Acting Diagnostic Algorithm of Insulated Gate Bipolar Transistor Open Circuit Faults for Power Inverters in Electric Vehicles

    Directory of Open Access Journals (Sweden)

    Lei Yu

    2017-04-01

    Full Text Available To improve the diagnostic detection speed in electric vehicles, a novel diagnostic algorithm of insulated gate bipolar transistor (IGBT open circuit faults for power inverters is proposed in this paper. The average of the difference between the actual three-phase current and referential three-phase current values over one electrical period is used as the diagnostic variable. The normalization method based on the amplitude of the d-q axis referential current is applied to the diagnostic variables to improve the response speed of diagnosis, and to avoid the noise and the delay caused by signal acquisition. In the parameter discretization process, the variable parameter moving average method (VPMAM is adopted to solve the variation of the average value over a period with the speed of the motor; hence, the diagnostic reliability of the system is improved. This algorithm is robust, independent of load variations, and has a high resistivity against false alarms. Since only the three-phase current of the motor is utilized for calculations in the time domain, a fast diagnostic detection speed can be achieved, which is significantly essential for real-time control in electric vehicles. The effectiveness of the proposed algorithm is verified by both simulation and experimental results.

  8. Functional Dependence for Calculation of Additional Real-Power Losses in a Double-Wound Supply Transformer Caused by Unbalanced Active Inductive Load in a Star Connection with an Insulated Neutral

    Science.gov (United States)

    Kostinskiy, Sergey S.; Troitskiy, Anatoly I.

    2016-01-01

    This article deals with the problem of calculating the additional real-power losses in double-wound supply transformers with voltage class 6 (10)/0,4 kV, caused by unbalanced active inductive load connected in a star connection with an insulated neutral. When solving the problem, authors used the theory of electric circuits, method of balanced…

  9. Electric field driven destabilization of the insulating state in nominally pure LaMnO3.

    Science.gov (United States)

    Nath, Rajib; Raychaudhuri, A K; Mukovskii, Ya M; Mondal, Parthasarathi; Bhattacharya, Dipten; Mandal, P

    2013-04-17

    We report an electric field driven destabilization of the insulating state in nominally pure LaMnO3 single crystal with a moderate field which leads to a resistive state transition below 300 K. The transition is between the insulating state in LaMnO3 and a high resistance bad metallic state that has a temperature independent resistivity. The transition occurs at a threshold field (Eth) that shows a steep enhancement on cooling. While at lower temperatures the transition is sharp and involves a large change in resistance, it softens on heating and is eventually absent above 280 K. When the Mn(4+) content is increased by Sr substitution up to x = 0.1, the observed transition, although observable in a certain temperature range, softens considerably. This observation has been explained as a bias driven percolation type transition between two co-existing phases, where the majority phase is a charge and orbitally ordered polaronic insulating phase and the minority phase is a bad metallic phase. The mobile fraction f of the bad metallic phase deduced from the experimental data follows an activated kinetics as f = fo(E)exp(-Δ/kBT) with the activation energy Δ ≈ 200 meV, and the pre-factor fo(E) is a strong function of the field that leads to a rapid enhancement of f on application of field, leading to the resistive state transition. We suggest likely scenarios for such co-existing phases in nominally pure LaMnO3 that can lead to the bias driven percolation type transition.

  10. Effectiveness Analysis and Temperature Effect Mechanism on Chemical and Electrical-Based Transformer Insulation Diagnostic Parameters Obtained from PDC Data

    Directory of Open Access Journals (Sweden)

    Hanbo Zheng

    2018-01-01

    Full Text Available The dielectric monitoring/diagnostic tool, such as Polarization and Depolarization Current (PDC measurement, is now being widely applied to obtain the status of deteriorated transformers around the world. Nowadays, several works have reported that the chemical and electrical-based transformer insulation diagnostic parameters (absorption ratio, polarization index, paper conductivity, oil conductivity, insulation resistance, etc. can be easily calculated from the PDC data. It is a fact that before using these parameters to obtain the status of deteriorated transformers, the power engineers should prudently investigate the effectiveness of these parameters. However, there are few papers that investigate the important issue. In addition, the understanding of temperature effect mechanism on these parameters should also be prudently studied. In the present work, we firstly prepare several oil-impregnated pressboard specimens with various insulation statuses by using a sequence of thermal ageing and moisture absorption experiments launched in the laboratory, and then the PDC measurement is performed to obtain the chemical and electrical-based transformer insulation diagnostic parameters. Finally, we systematically interpret the effectiveness and temperature effect mechanism on these chemical and electrical-based transformer insulation diagnostic parameters.

  11. Electrical resistivity of assembled transparent inorganic oxide nanoparticle thin layers: influence of silica, insulating impurities, and surfactant layer thickness.

    Science.gov (United States)

    Bubenhofer, Stephanie B; Schumacher, Christoph M; Koehler, Fabian M; Luechinger, Norman A; Sotiriou, Georgios A; Grass, Robert N; Stark, Wendelin J

    2012-05-01

    The electrical properties of transparent, conductive layers prepared from nanoparticle dispersions of doped oxides are highly sensitive to impurities. Production of cost-effective thin conducting films for consumer electronics often employs wet processing such as spin and/or dip coating of surfactant-stabilized nanoparticle dispersions. This inherently results in entrainment of organic and inorganic impurities into the conducting layer leading to largely varying electrical conductivity. Therefore, this study provides a systematic investigation on the effect of insulating surfactants, small organic molecules and silica in terms of pressure dependent electrical resistivity as a result of different core/shell structures (layer thickness). Application of high temperature flame synthesis gives access to antimony-doped tin oxide (ATO) nanoparticles with high purity. This well-defined starting material was then subjected to representative film preparation processes using organic additives. In addition ATO nanoparticles were prepared with a homogeneous inorganic silica layer (silica layer thickness from 0.7 to 2 nm). Testing both organic and inorganic shell materials for the electronic transport through the nanoparticle composite allowed a systematic study on the influence of surface adsorbates (e.g., organic, insulating materials on the conducting nanoparticle's surface) in comparison to well-known insulators such as silica. Insulating impurities or shells revealed a dominant influence of a tunneling effect on the overall layer resistance. Mechanical relaxation phenomena were found for 2 nm insulating shells for both large polymer surfactants and (inorganic) SiO(2) shells.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2016-01-18

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

  13. Heat transfer through the electrical insulation of Nb3Sn cables

    CERN Document Server

    Granieri, P; van Weelderen, R

    2014-01-01

    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.

  14. Identification of Droplet-Flow-Induced Electric Energy on Electrolyte-Insulator-Semiconductor Structure.

    Science.gov (United States)

    Park, Junwoo; Song, Suhwan; Yang, YoungJun; Kwon, Soon-Hyung; Sim, Eunji; Kim, Youn Sang

    2017-08-16

    Recently, various energy transducers driven by the relative motion of solids and liquids have been demonstrated. However, in relation to the energy transducer, a proper understanding of the dynamic behavior of ions remains unclear. Moreover, the energy density is low for practical usage mainly due to structural limitations, a lack of material development stemming from the currently poor understanding of the mechanisms, and the intermittently generated electricity given the characteristics of the water motion (pulsed signals). Here, we verify a hypothesis pertaining to the ion dynamics which govern the operation mechanism of the transducer. In addition, we demonstrate enhanced energy transducer to convert the mechanical energy of flowing water droplets into continuous electrical energy using an electrolyte-insulator-semiconductor structure as a device structure. The output power per droplet mass and the ratio of generated electric energy to the kinetic energy of water drops are 0.149v2 mW·g-1·m-2·s2 and 29.8%, respectively, where v is the speed of the water droplet.

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

    Directory of Open Access Journals (Sweden)

    Julionas KALADE

    2016-05-01

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

  16. Density-Polarization Functional Theory of the response of a periodic insulating solid to an electric field.

    OpenAIRE

    Gonze, X.; Ghosez, Ph.; Godby, R. W.; .

    1995-01-01

    The response of an infinite, periodic, insulating, solid to an infinitesimally small electric field is investigated in the framework of Density Functional Theory. We find that the applied perturbing potential is not a unique functional of the periodic density change~: it depends also on the change in the macroscopic {\\em polarization}. Moreover, the dependence of the exchange-correlation energy on polarization induces an exchange-correlation electric field. These effects are exhibited for a m...

  17. Density-polarisation functional theory of the response of a periodic insulating solid to an electric field

    OpenAIRE

    Godby, R. W.; Gonze, X.; Ghosez, P

    1995-01-01

    The response of an infinite, periodic, insulating, solid to an infinitesimally small electric field is investigated in the framework of Density Functional Theory. We find that the applied perturbing potential is not a unique functional of the periodic density change~: it depends also on the change in the macroscopic {\\em polarization}. Moreover, the dependence of the exchange-correlation energy on polarization induces an exchange-correlation electric field. These effects are exhibited for a m...

  18. Dielectric and insulating properties of an acrylic DEA material at high near-DC electric fields

    Science.gov (United States)

    Di Lillo, L.; Schmidt, A.; Bergamini, A.; Ermanni, P.; Mazza, E.

    2011-04-01

    A number of adaptive structure applications call for the generation of intense electric fields (in excess of 70 MV/m). Such intense fields across the thickness of a thin polymer dielectric layer are typically used to exploit the direct electromechanical coupling in the form of a Maxwell stress: (see manuscript) Where V/d is the applied field, ɛ0 is the permittivity of vacuum and ɛ is the relative permittivity of the material. The field that can be applied to the dielectric is limited by the dielectric strength of the material. Below the limit set by the breakdown, the material is generally assumed to have a field independent dielectric constant and to be a perfect insulator, i.e. to have an infinite volume resistivity. While extensive investigations about the mechanical properties of the materials used for electronic Dielectric Elastomer Actuators (DEA) are available from literature, the results of the investigation of the insulating and dielectric properties of these materials, especially under conditions (electric field and frequency) similar to the ones encountered during operation are not available. In the present contribution, we present a method and a set-up for the measurement of the electric properties of thin polymer films, such as the ones used for the fabrication of electronic DEAs, under conditions close to operations. The method and setup where developed to investigate the properties of 'stiff' thin polymer films, such as Polyimide or Polyvinylidenefluoride, used for Electro-Bonded Laminates (EBLs). The properties of the well known VHB 4910 acrylic elastomer are presented to illustrate how the permittivity and the leakage current can be measured as a function of the electric field and the deformation state, using the proposed set-up. The material properties were measured on membranes under different fixed pre-stretch conditions (λ 1, λ2=3, 4, 5), in order to eliminate effects due to the change in sample geometry, using gold sputtered electrodes, 20

  19. Thermally conductive and electrically insulating EVA composite encapsulant for solar photovoltaic (PV cell

    Directory of Open Access Journals (Sweden)

    2008-05-01

    Full Text Available A new way of improving the heat dissipating ability and PV efficiency of the solar cells by enhancing the thermal conductivity of the rear EVA layer was reported. The thermal conductivity, electrical resistivity, degree of curing of the EVA encapsulating composites and the PV efficiency of the solar cells are investigated. Filling with the thermal conductive fillers enhances the thermal conductivity of the composites effectively. The thermal conductivity of the filler influences significantly the thermal conductivity of the composite at high filler loading (greater than 20 vol%. Thermal conductivities of the composites filled with SiC, ZnO or BN reach respectively 2.85, 2.26 and 2.08 W/m•K at filler content of 60 vol%. The composites filled with ZnO or BN exhibit superior electrical insulation to those filled with SiC or Al2O3. ZnO can promote the cross-linking reaction of the EVA matrix. The test results indicated that the EVA composite encapsulating rear films filled with thermal conductive fillers are able to improve the PV efficiency and the heat dissipating ability of the solar cell effectively.

  20. Measurement of insulating and dielectric properties of acrylic elastomer membranes at high electric fields

    Science.gov (United States)

    Di Lillo, L.; Schmidt, A.; Carnelli, D. A.; Ermanni, P.; Kovacs, G.; Mazza, E.; Bergamini, A.

    2012-01-01

    This work reports on the investigation of VHB 4910 acrylic elastomer insulating and dielectric properties. This material is widely exploited for the realization of actuators with large deformations, dielectric elastomer actuators (DEA), and belongs to the group of so-called electroactive polymers (EAP). Extensive investigations concerning its mechanical properties are available in literature while its electric behavior at working conditions has not received the same level of attention. In this work, the relative permittivity and the volume resistivity have been measured on VHB 4910 membranes under different fixed stretch conditions (λ1, λ2 = 3, 3.6, 4, 5) using circular gold electrodes sputtered onto both sides of the specimens. The measured values of relative permittivity are in fairly good agreement with the results previously published by other groups. The volume resistivity, at field values close to the operational ones, has shown a field-dependent behavior revealing dissipative properties that should be considered in real applications. Further, measurements on circular actuators verify these findings. Consequences for modeling of VHB 4910 are drawn and new material model parameters proposed to account for the value of relative permittivity at high electric fields.

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

    Directory of Open Access Journals (Sweden)

    Wei Xun

    2017-07-01

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

  2. Initial and long-term frequency degradation of ring oscillators caused by plasma-induced damage in 65 nm bulk and fully depleted silicon-on-insulator processes

    Science.gov (United States)

    Kishida, Ryo; Oshima, Azusa; Yabuuchi, Michitarou; Kobayashi, Kazutoshi

    2015-04-01

    The degradation of reliability caused by plasma-induced damage (PID) has become a significant concern with the miniaturization of device size. In particular, it is difficult to relieve PID in silicon-on-insulator (SOI) because it contains buried oxide (BOX) layers. In this work, we compare PID between a bulk and a silicon on thin BOX (SOTB), which has BOX layers of less than 10 nm. We measure frequencies of ring oscillators with an antenna structure on a single stage. In the bulk, PID is relieved by first connecting an antenna to a drain because electric charge flows to a substrate. The difference in initial frequency is 0.79% between structures, which cause and relieve PID. SOTB also relieves the same amount of PID. Initial frequencies are affected by PID, but there is no effect of PID on the long-term degradation mainly caused by bias temperature instability (BTI).

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

    Science.gov (United States)

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

    2017-01-01

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

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

    Science.gov (United States)

    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.

  5. Cooling of electrically insulated high voltage electrodes down to 30 mK: Dynamic measurements

    CERN Document Server

    Eisel, T; Burghart, G; Feigl, S; Haug, F; Koettig, T

    2011-01-01

    AEgIS [1] is an antimatter experiment, using high voltage electrodes at 100 mK. Two possible principles to cool these electrodes with a dilution refrigerator are investigated: the Rod and the Sandwich. Both designs are described in detail in [2]. The Sandwich design is discussed in the present work. It consists of an electrically insulating sapphire plate covered with indium on both sides. Dynamic measurements are performed in order to estimate the influence of time depending heat loads on different Sandwich designs. From these data the Sandwich’s thermal diffusivity is derived and compared to previous measurements using a static heat load. The lowest resistivity of the Sandwich is achieved with an indium vapor deposition onto polished sapphire (26 cm2K4/W at 30 mK). The same sandwich shows the best, i.e. highest thermal diffusivity (0.23 mm2/s at 70 mK). However, the results of the static and the dynamic measurements show some interesting and contrary tendencies.

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

    Energy Technology Data Exchange (ETDEWEB)

    Guo, Junji; Liao, Wenhu, E-mail: whliao2007@aliyun.com; 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)

    2014-01-14

    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.

  7. Density-Polarization Functional Theory of the Response of a Periodic Insulating Solid to an Electric Field

    Science.gov (United States)

    Gonze, X.; Ghosez, Ph.; Godby, R. W.

    1995-05-01

    The response of an infinite, periodic, insulating solid to an infinitesimally small electric field is investigated in the framework of density functional theory. We find that the applied perturbing potential is not a unique functional of the periodic density change; it depends also on the change in the macroscopic polarization. Moreover, the dependence of the exchange-correlation energy on polarization induces an exchange-correlation electric field. These effects are exhibited for a model semiconductor. We also show that the scissor-operator technique is an approximate way of bypassing this polarization dependence.

  8. Thermal and electrical properties of thermal-grease-insulated REBCO superconducting coils with respect to winding tension

    Science.gov (United States)

    Song, Jung-Bin; Choi, Yoon Hyuck; Yang, Dong Gyu; Kim, Young-Gyun; Kim, Seong-Gyeom; Choi, Yeon Suk; Lee, Haigun

    2017-09-01

    This study investigates the thermal and electrical characteristics of a silicon-based grease insulation (GI) GdBCO coil with respect to the winding tension through charge, sudden discharge, and over-current tests. Charge and sudden discharge test results demonstrate that the charging/discharging delay time increases as the winding tension increases; this is because the characteristic resistance of the coil decreases due to the reduced contact resistance. The over-current test results confirm that the thermal/electrical stabilities of the GI coil are considerably enhanced with an increased winding tension resulting from improved thermal contact and the decrease in the electrical contact resistance between the turn-to-turn layers of the coil. Thus, as the winding tension increases, the charging/discharging rates decrease whereas the thermal/electrical stabilities improve. Overall, selecting the appropriate winding tension for a GI coil is critical for achieving thermal/electrical stabilities, as well as ameliorating the charging/discharging delay phenomenon generally observed in a no-insulation coil.

  9. Strongly correlated material under voltage: The electrical breakdown in V{sub 2}O{sub 3} at the insulator to metal transition

    Energy Technology Data Exchange (ETDEWEB)

    Guenon, Stefan; Wang, Siming; Ramirez, Juan Gabriel; Schuller, Ivan K. [Department of Physics and Center for Advanced Nanoscience, University of California, San Diego (United States); Scharinger, Sebastian; Koelle, Dieter; Kleiner, Reinhold [Physikalisches Institut and Center for Collective Quantum Phenomena and their Applications in LISAplus, Universitaet Tuebingen (Germany)

    2013-07-01

    We have investigated the electrical properties of a V{sub 2}O{sub 3} thin film micro bridge. Discontinuous jumps to lower voltages in the current voltage characteristic (IV) followed by an approximately constant voltage progression for high currents indicate an electrical breakdown of the device. In addition, the IV curves show hysteresis and a training effect, i.e. the subsequent IV loops are different from the first IV loop after thermal cycling. Low temperature scanning electron microscopy (LTSEM) reveals that the electrical breakdown over the whole device is caused by the formation of electro-thermal domains (ETDs), i.e. the current and temperature redistribution. On the contrary, at the nanoscale, the electrical breakdown causes the insulator to metal transition of individual domains. In a numerical model we considered these domains as a network of resistors and we were able to reproduce the electro-thermal breakdown as well as the hysteresis and the training effect in the IVs.

  10. An unusual electrical burn caused by alkaline batteries

    Directory of Open Access Journals (Sweden)

    Tyng-Luen Roan

    2015-02-01

    Full Text Available Electrical burns caused by low-voltage batteries are rarely reported. We recently encountered a male patient who suffered from a superficial second-degree burn over his left elbow and back. The total body surface area of the burn was estimated to be 6%. After interviewing the patient, the cause was suspected to be related to the explosion of a music player on the left-side of his waist, carried on his belt while he was painting a bathroom wall. Elevated creatine kinase levels and hematuria indicated rhabdomyolysis and suggested an electrical burn. Initial treatment was done in the burn intensive care unit with fluid challenge and wound care. The creatine kinase level decreased gradually and the hematuria was gone after 4 days in the intensive care unit. He was then transferred to the general ward for further wound management and discharged from our burn center after a total of 11 days without surgical intervention.

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

    Directory of Open Access Journals (Sweden)

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

    2010-01-01

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

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

    Science.gov (United States)

    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

  13. Investigation of thermal and electrical stabilities of a GdBCO coil using grease as an insulation material for practical superconducting applications.

    Science.gov (United States)

    Kang, D H; Kim, K L; Kim, Y G; Park, Y J; Kim, W J; Kim, S H; Lee, H G

    2014-09-01

    This paper presents the effects of thermal grease on the electrical and thermal characteristics of GdBCO pancake coils, observed through charge-discharge, sudden discharge, over-current, and thermal quench testing. In charge-discharge and sudden discharge tests, a coil using thermal grease as an insulation material demonstrated faster charging/discharging rates compared to a coil without turn-to-turn insulation. In the case of over-current tests, the coil using thermal grease exhibited the highest electrical stability. Furthermore, thermal quench testing showed the coil employing thermal grease to possess superior thermal characteristics, with rapid cooling and low temperature rise. Overall, the use of thermal grease as an insulation material may be a potential solution to the problems observed with the existing insulation materials, possessing fast charging/discharging rates with superior thermal and electrical stabilities.

  14. Measurements of Electrical and Electron Emission Properties of Highly Insulating Materials

    Science.gov (United States)

    Dennison, J. R.; Brunson, Jerilyn; Hoffman, Ryan; Abbott, Jonathon; Thomson, Clint; Sim, Alec

    2005-01-01

    Highly insulating materials often acquire significant charges when subjected to fluxes of electrons, ions, or photons. This charge can significantly modify the materials properties of the materials and have profound effects on the functionality of the materials in a variety of applications. These include charging of spacecraft materials due to interactions with the severe space environment, enhanced contamination due to charging in Lunar of Martian environments, high power arching of cables and sources, modification of tethers and ion thrusters for propulsion, and scanning electron microscopy, to name but a few examples. This paper describes new techniques and measurements of the electron emission properties and resistivity of highly insulating materials. Electron yields are a measure of the number of electrons emitted from a material per incident particle (electron, ion or photon). Electron yields depend on incident species, energy and angle, and on the material. They determine the net charge acquired by a material subject to a give incident flu. New pulsed-beam techniques will be described that allow accurate measurement of the yields for uncharged insulators and measurements of how the yields are modified as charge builds up in the insulator. A key parameter in modeling charge dissipation is the resistivity of insulating materials. This determines how charge will accumulate and redistribute across an insulator, as well as the time scale for charge transport and dissipation. Comparison of new long term constant-voltage methods and charge storage methods for measuring resistivity of highly insulating materials will be compared to more commonly used, but less accurate methods.

  15. Effects of additional oxidation after Ge condensation on electrical properties of germanium-on-insulator p-channel MOSFETs

    Science.gov (United States)

    Suh, Junkyo; Nakane, Ryosho; Taoka, Noriyuki; Takenaka, Mitsuru; Takagi, Shinichi

    2016-03-01

    This paper discusses the effects of additional oxidation after Ge condensation on electrical characteristics of fully depleted germanium-on-insulator (FDGOI) p-channel MOSFETs. We highlight the passivation of the back interface of GOI layers by the additional oxidation. Moreover, the electrical characteristics of the fabricated GOI pMOSFETs were systematically analyzed with varying the additional oxidation time and resulting compressive strain. It is found that 12-nm-thick GOI pMOSFETs with 0.94 % compressive strain were realized without any additional oxidation by utilizing strained silicon-on-insulator (sSOI), showing the drive current over twice as high as that of unstrained Ge pMOSFETs. However, the devices exhibit large positive threshold voltage (Vth) shifts, large subthreshold swing (SS), and high off-state current (Ioff), attributable to the poor MOS interfaces with buried oxides (BOX). This back channel MOS interface can be effectively passivated without significant growth of the BOX thickness by additional oxidation, leading to the restoration of the Vth shifts, improved SS, and dramatic reduction of Ioff. It is also found that the improvement of the back interface (Ge/BOX) and the strain relaxation occur simultaneously by the additional oxidation, which is corroborated by Raman spectroscopy, transmission electron microscopy (TEM), and the electrical characterization of GOI pMOSFETs. As a result, a possible physical model to explain the observed phenomena was proposed.

  16. Some Observations on the Dielectric Breakdown and the Importance of Cavities in Insulating Materials used for Cables and Electrical Machines

    Directory of Open Access Journals (Sweden)

    KARLIS, A. D.

    2011-05-01

    Full Text Available Partial discharges (PD contribute greatly to the ageing and the breakdown of solid insulating materials. In the present paper, some conductivity measurements are performed relating the conductivity of inner walls of an enclosed cavity to the behaviour of PD in the case of polyethylene and of epoxy resin. The temporary decrease of the PD magnitude is explained in terms of the increase of the cavity inner wall conductivity. The PD behaviour is studied in epoxy resin samples and is explained with the aid of Pedersen's model. Scanning Electron Microscope (SEM photographs indicate the sort of damage suffered by the cavity walls under electrical stress.

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

    Directory of Open Access Journals (Sweden)

    KHOUILDI Emna

    2016-10-01

    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.

  18. Electric preheating - a new method for laying pre-insulated district heating pipes. District heating schemes on-line faster

    Energy Technology Data Exchange (ETDEWEB)

    Lambertsen, E.; Pedersen, H.N.

    1990-01-01

    i.c.moeller a/s of Fredericia, Denmark, is one of the world's leading manufacturers of pre-insulated pipe systems. The company, a member of the ABB Group, has refined district heating pipeline design to a degree where heat losses can be neglected over distances of 100 km and more. Pipe installation is also undergoing continuing improvement at i.c.moeller, which has developed a method of electric preheating that makes it easier to prestress friction-locked pipe systems. This method has also proved successful for large-diameter pipes. (orig.).

  19. Electric multipole moments, topological multipole moment pumping, and chiral hinge states in crystalline insulators

    Science.gov (United States)

    Benalcazar, Wladimir A.; Bernevig, B. Andrei; Hughes, Taylor L.

    2017-12-01

    We extend the theory of dipole moments in crystalline insulators to higher multipole moments. As first formulated in Benalcazar et al. [Science 357, 61 (2017), 10.1126/science.aah6442], we show that bulk quadrupole and octupole moments can be realized in crystalline insulators. In this paper, we expand in great detail the theory presented previously [Benalcazar et al., Science 357, 61 (2017), 10.1126/science.aah6442] and extend it to cover associated topological pumping phenomena, and a class of three-dimensional (3D) insulator with chiral hinge states. We start by deriving the boundary properties of continuous classical dielectrics hosting only bulk dipole, quadrupole, or octupole moments. In quantum mechanical crystalline insulators, these higher multipole bulk moments manifest themselves by the presence of boundary-localized moments of lower dimension, in exact correspondence with the electromagnetic theory of classical continuous dielectrics. In the presence of certain symmetries, these moments are quantized, and their boundary signatures are fractionalized. These multipole moments then correspond to new symmetry-protected topological phases. The topological structure of these phases is described by "nested" Wilson loops, which we define. These Wilson loops reflect the bulk-boundary correspondence in a way that makes evident a hierarchical classification of the multipole moments. Just as a varying dipole generates charge pumping, a varying quadrupole generates dipole pumping, and a varying octupole generates quadrupole pumping. For nontrivial adiabatic cycles, the transport of these moments is quantized. An analysis of these interconnected phenomena leads to the conclusion that a new kind of Chern-type insulator exists, which has chiral, hinge-localized modes in 3D. We provide the minimal models for the quantized multipole moments, the nontrivial pumping processes, and the hinge Chern insulator, and describe the topological invariants that protect them.

  20. An unusual electrical burn caused by alkaline batteries.

    Science.gov (United States)

    Roan, Tyng-Luen; Yeong, Eng-Kean; Tang, Yueh-Bih

    2015-02-01

    Electrical burns caused by low-voltage batteries are rarely reported. We recently encountered a male patient who suffered from a superficial second-degree burn over his left elbow and back. The total body surface area of the burn was estimated to be 6%. After interviewing the patient, the cause was suspected to be related to the explosion of a music player on the left-side of his waist, carried on his belt while he was painting a bathroom wall. Elevated creatine kinase levels and hematuria indicated rhabdomyolysis and suggested an electrical burn. Initial treatment was done in the burn intensive care unit with fluid challenge and wound care. The creatine kinase level decreased gradually and the hematuria was gone after 4 days in the intensive care unit. He was then transferred to the general ward for further wound management and discharged from our burn center after a total of 11 days without surgical intervention. Copyright © 2012. Published by Elsevier B.V.

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

    Energy Technology Data Exchange (ETDEWEB)

    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: rmorales@uchile.cl; Seelenfreund, A. [Universidad Academia de Humanismo Cristiano, Condell 343, Providencia, Santiago (Chile)

    2007-10-15

    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.

  2. The Problem of Biological Destruction of Façades of Insulated Buildings - Causes and Effects

    Science.gov (United States)

    Stanaszek-Tomal, Elżbieta

    2017-10-01

    The Regulation of the Minister of Infrastructure concerning the technical conditions of buildings and their location required new designed buildings to have reduced amount of heat that is transmitted through the barrier. This involves the use of thermal insulation, of adequate thickness to meet the relevant requirements. As the environment conditions are favourable, the façades may deteriorate. Major aggressors include algae fungi or lichens, i.e. the formation of symbiotic growth of algae and fungi. Their construction, metabolic processes are the basis of knowledge about action to prevent corrosion.

  3. Resistance noise spectroscopy across the thermally and electrically driven metal-insulator transitions in VO2 nanobeams

    Science.gov (United States)

    Alsaqqa, Ali; Kilcoyne, Colin; Singh, Sujay; Horrocks, Gregory; Marley, Peter; Banerjee, Sarbajit; Sambandamurthy, G.

    Vanadium dioxide (VO2) is a strongly correlated material that exhibits a sharp thermally driven metal-insulator transition at Tc ~ 340 K. The transition can also be triggered by a DC voltage in the insulating phase with a threshold (Vth) behavior. The mechanisms behind these transitions are hotly discussed and resistance noise spectroscopy is a suitable tool to delineate different transport mechanisms in correlated systems. We present results from a systematic study of the low frequency (1 mHz noise behavior in VO2 nanobeams across the thermally and electrically driven transitions. In the thermal transition, the power spectral density (PSD) of the resistance noise is unchanged as we approach Tc from 300 K and an abrupt drop in the magnitude is seen above Tc and it remains unchanged till 400 K. However, the noise behavior in the electrically driven case is distinctly different: as the voltage is ramped from zero, the PSD gradually increases by an order of magnitude before reaching Vth and an abrupt increase is seen at Vth. The noise magnitude decreases above Vth, approaching the V = 0 value. The individual roles of percolation, Joule heating and signatures of correlated behavior will be discussed. This work is supported by NSF DMR 0847324.

  4. Comparative Investigation of Pollution Accumulation and Natural Cleaning for Different HV Insulators

    OpenAIRE

    Dimitropoulou, M; D. Pylarinos; K. Siderakis; Thalassinakis, E.; Danikas, M.

    2015-01-01

    High Voltage insulators are scattered throughout any HV network and a single insulator fault may cause an excessive outage. Reliability is a key issue for electric power systems and fault-free performance of insulators greatly reflects on the reliability of the system. Environmental influence is rather important for the optimum selection of outdoor insulators and, therefore, field measurements provide valuable information. Utilities perform such measurements in order to decide upon the locati...

  5. Electric strength of insulation on superhigh-voltage overhead transmission lines

    Energy Technology Data Exchange (ETDEWEB)

    Danis, J.; Kromer, I.L.

    1979-09-01

    Insulation for superhigh-voltage overhead transmission lines is selected on the basis of reliability during switching overvoltages and extreme changes in ambient conditions. A study of 400 kV and 750 kV insulator strings, porcelain and glass, respectively, was made to determine their performance with dusty or moist surface under these severe conditions as expected in service. Four different configurations of a double string suspended from a cross beam 30 m above ground and at various horizontal distances from lateral poles were tested. The risetime of aperiodic voltage pulses was varied from 35 ..mu..s (below critical) to 1200..mu..s (above critical) and their duration was varied from 1000 to 10,500 ..mu..s, the voltage level changed in 5% steps and successive pulses applied in 30 to 40 s intervals. The 50%-discharge voltage was estimated by the up and down method and the readings evaluated statistically by Student's method. The results yielded the voltage-time characteristics of these insulator strings, with the dip of the 50%-discharge voltage down to its minimum critical level corresponding to an overvoltage pulse with the critical risetime. Further analysis yields also the risk and the number of flashhovers, depending on the contamination distribution density, on the overvoltage amplitude distribution density, and on the number of weak spots. Contamination increases the probable number of flashovers during switching by 30 to 50%.

  6. Underground electrical power transmission lines in coastal areas: Insulation and installation. Problemi connessi con posa e esercizio di cavi elettrici di potenza in ambiente lagunare

    Energy Technology Data Exchange (ETDEWEB)

    Bisiach, L.; Cerretti, A.; Cocchiglia, A. (Ente Nazionale per l' Energia Elettrica, Venice (Italy))

    1992-12-01

    The coastal area of Venice, crossed by an intricate network of salt water canals, presents particular problems for engineers planning the installation of underground power transmission lines. This paper traces the development, by ENEL (the Italian National Electricity Board), of suitable electrical insulation specifications to counter the destructive physical-chemical effects on power cables of highly corrosive coastal lagoon environments. Cable trench excavation, cable installation and trench back-filling methods are described specifying suitable depths, choice and layering of materials designed to adequately protect buried high and medium voltage lines crossing navigable canals. Reference is made to the relative Italian normatives governing power cable insulation and installation.

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

    KAUST Repository

    Lim, Seungjae

    2015-04-01

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

  8. Contribution of ethylenetetrafluoroethylene (ETFE) insulation to the electrical performance of Riata® silicone leads having externalized conductors.

    Science.gov (United States)

    Fischer, Avi; Klehn, Russell

    2013-08-01

    The insulation of St. Jude Medical Riata® leads contains a polytetrafluoroethylene (PTFE) liner, silicone tubing, and ethylenetetrafluoroethylene (ETFE) coating on individual cable conductors. ETFE has sufficient dielectric strength to assure electrical function. This investigation intended to analyze performance of leads with and without externalized conductors and with intact and breached ETFE. Testing was performed on ETFE-coated conductors to determine their ability to deliver high-voltage therapy. Tests were performed on samples under different conditions and current leakage was measured. A high-voltage test and a cyclic pulse test were performed, and the effect of lead modifications on the potential gradient from a high-voltage shock was used to determine functionality. Measurements from modified Riata® leads were compared with a control lead with all insulation and conducting elements intact. Current leakage for all conditions tested, was within the acceptance criteria for the high-voltage test and the cyclic pulse test. In conductors that underwent cyclic testing, the highest value of current leakage was within the limit of acceptability for both phases of the test. Testing of leads with externalized conductors and breached ETFE showed similar potential gradients compared with a control lead. Testing of ETFE-coated conductors following multiple preconditioning steps showed that ETFE serves as a redundant layer of insulation. In the event that the ETFE coating is breached, the potential gradient seen resulting from a high-voltage defibrillation shock was similar to a lead with no breach to the ETFE, even after 100 shocks.

  9. Role of geometric parameters in electrical measurements of insulating thin films deposited on a conductive substrate

    Science.gov (United States)

    Kumar, S.; Gerhardt, R. A.

    2012-03-01

    The effects of film thickness, electrode size and substrate thickness on the impedance parameters of alternating frequency dielectric measurements of insulating thin films deposited on conductive substrates were studied through parametric finite-element simulations. The quasi-static forms of Maxwell's electromagnetic equations in a time harmonic mode were solved using COMSOL Multiphysics® for several types of 2D models (linear and axisymmetric). The full 2D model deals with a configuration in which the impedance is measured between two surface electrodes on top of a film deposited on a conductive substrate. For the simplified 2D models, the conductive substrate is ignored and the two electrodes are placed on the top and bottom of the film. By comparing the full model and the simplified models, approximations and generalizations are deduced. For highly insulating films, such as the case of insulating SiO2 films on a conducting Si substrate, even the simplified models predict accurate capacitance values at all frequencies. However, the edge effects on the capacitance are found to be significant when the film thickness increases and/or the top electrode contact size decreases. The thickness of the substrate affects predominantly the resistive components of the dielectric response while having no significant effect on the capacitive components. Changing the electrode contact size or the film thickness determines the specific values of the measured resistance or capacitance while the material time constant remains the same, and thus this affects the frequency dependence that is able to be detected. This work highlights the importance of keeping in mind the film thickness and electrode contact size for the correct interpretation of the measured dielectric properties of micro/nanoscale structures that are often investigated using nanoscale capacitance measurements.

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

    Science.gov (United States)

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

    2017-01-01

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

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

    Directory of Open Access Journals (Sweden)

    Deepak Kumar Kaushik

    2017-01-01

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

  12. Low temperature plasma enhanced chemical vapor deposition of thin films combining mechanical stiffness, electrical insulation, and homogeneity in microcavities

    Science.gov (United States)

    Peter, S.; Günther, M.; Hauschild, D.; Richter, F.

    2010-08-01

    The deposition of hydrogenated amorphous carbon (a-C:H) as well as hydrogenated amorphous silicon carbonitride (SiCN:H) films was investigated in view of a simultaneous realization of a minimum Young's modulus (>70 GPa), a high electrical insulation (≥1 MV/cm), a low permittivity and the uniform coverage of microcavities with submillimeter dimensions. For the a-C:H deposition the precursors methane (CH4) and acetylene (C2H2) were used, while SiCN:H films were deposited from mixtures of trimethylsilane [SiH(CH3)3] with nitrogen and argon. To realize the deposition of micrometer thick films with the aforementioned complex requirements at substrate temperatures ≤200 °C, several plasma enhanced chemical vapor deposition methods were investigated: the capacitively coupled rf discharge and the microwave electron cyclotron resonance (ECR) plasma, combined with two types of pulsed substrate bias. SiCN:H films deposited at about 1 Pa from ECR plasmas with pulsed high-voltage bias best met the requirements. Pulsed biasing with pulse periods of about 1 μs and amplitudes of about -2 kV was found to be most advantageous for the conformal low temperature coating of the microtrenches, thereby ensuring the required mechanical and insulating film properties.

  13. Transforming common III-V/II-VI insulating building blocks into topological heterostructure via the intrinsic electric polarization

    Science.gov (United States)

    Zunger, Alex; Zhang, Xiuwen; Abdalla, Leonardo; Liu, Qihang

    Currently known topological insulators (TIs) are limited to narrow gap compounds incorporating heavy elements, thus severely limiting the material pool available for such applications. We show how a heterovalent superlattice made of common semiconductor building blocks can transform its non-TI components into a topological heterostructure. The heterovalent nature of such interfaces sets up, in the absence of interfacial atomic exchange, a natural internal electric field that along with the quantum confinement leads to band inversion, transforming these semiconductors into a topological phase while also forming a giant Rashba spin splitting. We demonstrate this paradigm of designing TIs from ordinary semiconductors via first-principle calculations on III-V/II-VI superlattice InSb/CdTe. We illustrate the relationship between the interfacial stability and the topological transition, finding a ``window of opportunity'' where both conditions can be optimized. This work illustrates the general principles of co-evaluation of TI functionality with thermodynamic stability as a route of identifying realistic combination of common insulators that could produce topological heterostructures. This work was supported by Basic Energy Science, MSE division (Grant DE-FG02-13ER46959).

  14. Electrical Burn Causing a Unique Pattern of Neurological Injury

    Directory of Open Access Journals (Sweden)

    Nathan R. Schaefer, BExSc, MBBS (Hons

    2015-04-01

    Full Text Available Summary: Neurological involvement is not uncommon in patients who sustain electrical injury. The exact mechanism of nervous system damage following electrical trauma is not fully understood. The gamut of possible neurologic manifestations following electrical injury is diverse. This case report describes a young man with a unique pattern of neurological injury following an electrical burn. The combination of brachial plexopathy, partial Horner’s syndrome, and phrenic nerve palsy secondary to electrical injury has not been previously described in the literature.

  15. Aligned Graphene Oxide Nanofillers: An Approach to Prepare Highly Thermally Conductive and Electrically Insulative Transparent Polymer Composites

    Directory of Open Access Journals (Sweden)

    Genlian Lin

    2015-01-01

    Full Text Available Graphene oxide (GO/polyvinyl alcohol composites with extremely high in-plane thermal conductivities are prepared by a simple tape casting process using water as process solvent. The in-plane thermal conductivity of the composite can reach 17.61 W/mK at only 0.1 wt% GO loading, which is close to that of fully dense alumina. The excellent thermal conducting ability, the unique two-dimensional morphology, and the all-wet handling of the GO fillers as well as the high orientation of the fillers in the polymer matrix all contribute to the high thermal conductivities achieved. Meanwhile, the composites show good electrical insulation property and decent transparency.

  16. Localization of Electrical Insulation Failures in Superconducting Collared Coils by Analysis of the Distortion of a Pulsed Magnetic Field

    CERN Document Server

    Komorowski, P A

    2000-01-01

    The localization of possible electrical faults in superconducting accelerator magnets may, in most cases, be a complex, expensive and time-consuming process. In particular, inter-turn short circuits and failures of the ground insulation are well detectable when the magnet is collared, but often disappear after disassembly for repair due to the release of the pre-stress in the coils. The fault localization method presented in this paper is based on the measurement and analysis of the magnetic field generated inside the magnet aperture by a high voltage pulse. The presence of the fault modifies the distribution of the current in the coils and produces a distortion of the magnetic field. The described method aims at locating both the longitudinal and azimuthal position of the fault-affected area. The test method, the transient case FEM models and the implemented experimental set-up are presented and discussed for the LHC dipole models.

  17. Examples of occupational exposure to electric and magnetic fields at 110-kV gas-insulated substations (GISs).

    Science.gov (United States)

    Korpinen, Leena; Pääkkönen, Rauno

    2015-02-01

    The objectives of the study were to present examples of occupational exposure to electric and magnetic fields at gas-insulated substations (GISs) and to analyse the exposure according to the new European Directive 2013/35/EU. The aim was also to describe the details of the measurements of this study at GISs. Electric and magnetic fields were measured (45 measurements in total) at two GISs in the Tampere region of Finland. Inside the GISs, magnetic field values varied from 0.4 to 43.0 µT, and electric fields from 5 to 90 V m(-1). In the cable room of GIS B, the maximum value was 250 µT (very near the cables). The values did not exceed the low or high action levels of the new Directive 2013/35/EU. In conclusion, it can be stated that at 110-kV GISs, workers are not exposed to electromagnetic fields (EMFs) higher than the new European Directive 2013/35/EU. © The Author 2014. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  18. Electrical properties of germanium-based insulator-semiconductor structures with an insulating layer of polynucleotides, and their monomer components on the surface

    Energy Technology Data Exchange (ETDEWEB)

    Yafyasov, A. M., E-mail: yafyasov@bk.ru; Bakulev, V. M.; Konorov, P. P.; Bogevolnov, V. V. [St. Petersburg State University, Faculty of Physics (Russian Federation)

    2011-12-15

    It is shown that adsorption of nucleic acid molecules and their monomeric components, i.e., nitrogenous bases, from aqueous solutions results in the formation of an insulating layer on the germanium surface. Comparatively small values of the insulator charge and the surface-state density point to promising applications of nucleotides for both the formation of germanium-based insulator-semiconductor structures with nanoscale insulating layers and low surface-state densities at the phase interface, and for germanium surface passivation. Changes in the electronic properties of the space-charge region of germanium during nucleotide adsorption on its surface can be used as a method for determining the nucleotide molecule concentration in aqueous solutions.

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

    Energy Technology Data Exchange (ETDEWEB)

    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: ghania.farhi@usherbrooke.ca [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)

    2011-10-28

    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.

  20. Determination of threshold and maximum operating electric stresses for selected high voltage insulations. Task III. Investigation of high voltage capacitor insulation. Progress report No. 4

    Energy Technology Data Exchange (ETDEWEB)

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

    1984-03-01

    This report covers the investigation of threshold voltage of capacitor insulation. 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/sup 0/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/sup 0/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.

  1. Earth electricity: a review of mechanisms which cause telluric currents in the lithosphere

    Directory of Open Access Journals (Sweden)

    Daniel S. Helman

    2014-01-01

    Full Text Available Telluric currents are natural electrical phenomena in the Earth or its bodies of water. The strongest electric currents are related to lightning phenomena or space weather. Earth electricity can cause damage to structures, and may be useful for earthquake forecasting and other applications. Thirty-two distinct mechanisms that cause Earth electricity are described, and a broad selection of current research is highlighted.

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

    Science.gov (United States)

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

    2017-10-01

    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.

  3. Investigating the lubricity and electrical insulation caused by sanding in dry wheel–rail contacts

    NARCIS (Netherlands)

    Arias-Cuevas, O.; Li, Z.; Lewis, R.

    2009-01-01

    The adhesion (or available friction) in the wheel–rail contact is the most important parameter for the braking and traction operation of rail vehicles. Since the beginning of railway transportation, sanding from the locomotive has been a common practice to enhance the wheel–rail adhesion. In recent

  4. Electrically insulating properties of the 5d double perovskite Sr2YOsO6

    Science.gov (United States)

    Li, Jinghua; Wang, Xia; Wang, Hongyuan; Matsushita, Yoshitaka; Alexei, Belik A.; Kolodiazhnyi, Taras; Xu, Gang; Shi, Youguo; Guo, Yanfeng; Yamaura, Kazunari; Chen, Ying

    2017-09-01

    A high-pressure-synthesized double perovskite Sr2YOsO6 was investigated by synchrotron X-ray diffraction and measurements of its magnetic susceptibility, specific heat capacity, complex impedance, and complex dielectric constant. It crystallized into a monoclinic double perovskite structure (P21/n) with complete ordering of the Y and Os atoms. Its magnetic behaviors, including the antiferromagnetic transition temperature (˜52 K), Curie-Weiss effective moment [3.48(5) μB/Os], and Weiss temperature [-350.1(7) K], were close to the respective values of Sr2YOsO6 previously synthesized without an applied pressure of 6 GPa. Transport property measurements revealed that the lower limit of the activation energy was 192(1) meV and the charge gap remained open regardless of the presence of magnetic order, conflicting with the electron delocalization predicted by theoretical calculations. Further consideration, including theoretical and experimental investigations of the roles of spin-orbit coupling and U of the 5d electrons of Os 5d-t2g3, may assist in understanding the general magnetic and insulating behaviors of quasi-half-filled 5d-t2g3oxides in the perovskite category toward the use of 5d double perovskite for magnetic applications.

  5. Characterization of Chemical Trends in Magnetically Doped, Electrically Gated Topological Insulator Thin Films

    Science.gov (United States)

    Richardella, Anthony; Kandala, Abhinav; Lee, Joon Sue; Fraleigh, Robbie; Samarth, Nitin; Liu, Minhao; Ong, Nai Phuan; Tao, Jing

    2014-03-01

    Interfacing topological insulators (TIs) with magnetism breaks time reversal symmetry and opens a gap in the surface states at the Dirac point. This results in novel phenomena, such as the recently reported quantized conductance at zero applied external magnetic field due to the quantum anomalous Hall effect (QAHE) in Cr doped (BixSb1-x)2 Te3 [C-Z. Chang, et al., Science 340, 167 (2013)]. We have studied magnetically doped (BixSb1-x)2 Te3 thin films grown by MBE on SrTiO3(111) (STO) substrates using Cr, Fe and Mn as magnetic dopants and as a function of the Bi and Sb composition. These films are carefully characterized by XRD, AFM, SQUID magnetometry and TEM. The chemical composition is determined using SIMS, RBS and XRF. Low temperature transport shows a large gate-tunable Hall effect in Cr doped samples and systematically varying longitudinal magneto-conductance as the Fermi energy is tuned through the Dirac point. The origin of ferromagnetism and its dependence on the chemical potential, chemical composition and sample thickness is discussed. Funded by DARPA and ARO-MURI.

  6. Temperature dependent electrical transport in single Ge nanowires near insulator-metal transition

    Science.gov (United States)

    Raychaudhuri, Arup Kumar; Seth, Shaili; Das, Kaustuv

    We report low temperature (4K Resolution Transmission Electron Microscope and established their crystalline quality. A single nanowire dispersed on a Si/SiO2 substrate was connected by Cr/Au contacts made by electron beam lithography in 2-probe / 4-probe configurations. The undoped nanowires have a room temperature resistivity (ρ) of 2 ohm.cm or more (estimated carrier concentration ~1015/cm3) and below the 25K (where it shows carrier freeze out) the ρ rises to high value of 35 ohm.cm. For nanowires with ρ <= .01 ohm.cm at 300K , low temperature ρ becomes finite, signaling transition to a metallic state with negative temperature co-efficient of ρ. The critical composition for the insulator-metal transition is more than an order higher than that observed in the bulk. At low T (<25K) resistivity data in this regime can be fitted to weak-localization form ρ =ρ0 - aTp/2 with ρ0 the NW's ~ 0.5-3.5 mohm.cm, with the exponent p ~ 3-4 as expected from theoretical predictions. Acknowldge Financial Support from Department od Science and Technology, Government of India for Sponsored Project.

  7. Electric characteristics of organic thin-film transistors and logic circuits with a ferroelectric gate insulator

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Yong Suk [Electronics and Telecommunications Research Institute, Yuseong, Daejon 305-350 (Korea, Republic of)], E-mail: jullios@etri.re.kr; Chu, Hye Yong; Kim, Seong Hyun; Lim, Sang Chul; Koo, Jae Bon; Lee, Jung Hun; Ku, Chan Hoe; Lee, Jeong-Ik; Do, Lee-Mi; Hwang, Chi Sun; Park, Sang-He Ko; Kim, Gi Heon; Jung, Sung Mook [Electronics and Telecommunications Research Institute, Yuseong, Daejon 305-350 (Korea, Republic of)

    2007-07-16

    Organic electronic devices using a pentacene have improved importantly in the last several years. We fabricated pentacene organic thin-film transistors (OTFTs) with dielectric SiO{sub 2} and ferroelectric Pb(Zr{sub 0.3},Ti{sub 0.7})O{sub 3} (PZT) gate insulators. The organic devices using SiO{sub 2} and PZT films had the field-effect mobility of approximately 0.1 and 0.004 cm{sup 2}/V s, respectively. The drain current in the transfer curve of pentacene/PZT transistors showed a hysteresis behavior originated in a ferroelectric polarization switching. In order to investigate the polarization effect of PZT gate dielectrics in a logic circuit, the simple voltage inverter using SiO{sub 2} and PZT films was fabricated and measured by an output-input measurement. The gain of inverter at the poling-down state was approximately 7.2 and it was three times larger than the value measured at the poling-up state.

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

    Science.gov (United States)

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

    2013-07-01

    Uninterrupted chest compressions are a key factor in determining resuscitation success. Interruptions to chest compression are often associated with defibrillation, particularly the need to stand clear from the patient during defibrillation. It has been suggested that clinical examination gloves may provide adequate electrical resistance to enable safe hands-on defibrillation in order to minimise interruptions. We therefore examined whether commonly used nitrile clinical examination gloves provide adequate resistance to current flow to enable safe hands-on defibrillation. Clinical examination gloves (Kimberly Clark KC300 Sterling nitrile) worn by members of hospital cardiac arrest teams were collected immediately following termination of resuscitation. To determine the level of protection afforded by visually intact gloves, electrical resistance across the glove was measured by applying a DC voltage across the glove and measuring subsequent resistance. Forty new unused gloves (control) were compared with 28 clinical (non-CPR) gloves and 128 clinical (CPR) gloves. One glove in each group had a visible tear and was excluded from analysis. Control gloves had a minimum resistance of 120 kΩ (median 190 kΩ) compared with 60 kΩ in clinical gloves (both CPR (median 140 kΩ) and non-CPR groups (median 160 kΩ)). Nitrile clinical examination gloves do not provide adequate electrical insulation for the rescuer to safely undertake 'hands-on' defibrillation and when exposed to the physical forces of external chest compression, even greater resistive degradation occurs. Further work is required to identify gloves suitable for safe use for 'hands-on' defibrillation. Copyright © 2013 Elsevier Ireland Ltd. All rights reserved.

  9. Insulation Coordination and Failure Mitigation Concerns for Roust Dc Electrical Power Systems (Preprint)

    Science.gov (United States)

    2014-05-01

    create light, powerful and controllable motors through dc brushless technology. Unfortunately, some complications are created by the presence of high...have been developed to qualify random-wound induction motors for use with pulse-width-modulated drives to control motor speed and/or torque. This...Systems (Type I) Used in Rotating Electrical Machines Fed From Voltage Converters—Qualification and Quality Control Tests, International Standard

  10. Effect of multi-structured zinc oxide on the electrical properties of polypropylene insulating materials

    Science.gov (United States)

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

    2017-08-01

    In this paper, polypropylene (PP) nanocomposites filled with ZnO nanoparticles, nanowires and tera-needle-like whiskers were prepared by a melt blending method. The effects of multi-structure ZnO fillers on space charge, breakdown strength and electrical conductive current of PP nanocomposites were investigated. The nanocomposites presented a remarkable suppression on space charge by adding ZnO nanowires, while the addition of ZnO nanoparticles and tera-needle-like whiskers did not effectively suppress the space charge accumulation. The electrical field distortion occurred in the inner of the PP filled with ZnO nanoparticles and tera-needle-like whiskers were about 1.8 kV mm-1 and 3.3 kV mm-1, respectively. Compared with pure PP, the breakdown strength of the PP nanocomposites filled with ZnO nanoparticles and nanowires increased, while they decreased in PP nanocomposites filled with tera-needle-like ZnO whiskers. This work indicated that the improvements on the electrical properties, especially the charge transport and space charge suppression in the nanocomposites were closely related to the different structure of ZnO.

  11. A giant chiroptical effect caused by the electric quadrupole.

    Science.gov (United States)

    Wu, Tong; Zhang, Weixuan; Wang, Rongyao; Zhang, Xiangdong

    2017-04-20

    Recently, there has been great interest in studying ultrasensitive detection and characterization of biomolecules using plasmonic particles, because they are of considerable importance in biomedical science and pharmaceutics. So far, all the theories on plasmon-induced circular dichroism (CD) have been based on the dipole approximation; the electric quadrupolar contribution is generally considered to be relatively small and neglected. Here we demonstrate that the electric quadrupolar contribution not only cannot be ignored, but it also plays a key role in many cases. Particularly, for the chiral medium that possesses preferential molecular orientations and is located at the hotspot of plasmonic nanostructures, the plasmonic CD strength contributed by molecular electric quadrupoles (EQs) can be two orders of magnitude higher than that contributed by molecular electric/magnetic dipoles. Unlike the case of the dipole approximation, molecular EQ associated plasmonic CD activity appears mainly at the plasmonic resonance absorptions that facilitate the optically enhanced near-field with steep electric field gradients, and is correlated with the boosted emission rate of a molecular EQ. Based on such physical understandings, we can design nanostructures to realize a giant chiroptical effect using the EQ contribution according to the requirements, which provide a new strategy for ultrasensitive detection and quantification of molecular chirality.

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

    CERN Document Server

    Eisel, Thomas; Bremer, J

    2011-01-01

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

  13. [Cardiac resynchronisation therapy as a cause of the electrical storm].

    Science.gov (United States)

    Krupa, Wojciech; Lackowski, Jacek; Sielski, Sławomir; Dobosiewicz, Ryszard; Kubica, Jacek

    2007-11-01

    We report a case of young patient with dilated cardiomyopathy and implanted cardioverter-defibrillator in which resynchronisation therapy (CRT-D) induced an electrical storm. One month after implantation of a cardiac resynchronisation pacemaker (CRT-P) the patient suffered from ventricular tachycardia with poor haemodynamic status and was treated by implantation of a CRT-D with a Y adaptor. After replacement of the CRT-D due to Y adaptor damage (new device without a Y adaptor) we observed an electrical storm during ventricular pacing (biventricular, right and left ventricular pacing respectively). Changing pacing mode from DDDR to AAIR resolved ventricular tachycardias in that patient.

  14. Electrically Insulated Sensing of Respiratory Rate and Heartbeat Using Optical Fibers

    Directory of Open Access Journals (Sweden)

    Ernesto Suaste-Gómez

    2014-11-01

    Full Text Available Respiratory and heart rates are among the most important physiological parameters used to monitor patients’ health. It is important to design devices that can measure these parameters without risking or altering the subject’s health. In this context, a novel sensing method to monitor simultaneously the heartbeat and respiratory rate signals of patients within an electrically safety environment was developed and tested. An optical fiber-based sensor was used in order to detect two optical phenomena. Photo-plethysmography and the relation between bending radius and attenuation of optical fiber were coupled through a single beam light traveling along this fiber.

  15. Development of non-cellulosic insulation for transformers. Quarterly report No. 2, April 1980. General Electric No. CCR-80-07

    Energy Technology Data Exchange (ETDEWEB)

    Fessler, W.A.

    1980-01-01

    Work has continued on the development of an analytical model to demonstrate the advantages in both materials and losses to be gained by the utilization of thin insulation in transformers. Measurement of mechanical and electrical properties of film materials is underway. The aging and material compatibility of synthetic films in transformer oil, silicone, and R113 is being studied in a sealed-tube aging program. Several materials are on test and others are being readied for test.

  16. Designing and Implementation a Lab Testing Method for Power Cables Insulation Resistance According with STAS 10411-89, SR EN ISO/CEI/17025/2005

    Science.gov (United States)

    Dobra, R.; Pasculescu, D.; Marc, G.; Risteiu, M.; Antonov, A.

    2017-06-01

    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.

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

    DEFF Research Database (Denmark)

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

    2005-01-01

    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...

  18. A REVIEW OF EXPERIMENTAL STUDY AND PERFORMANCE OF INSULATOR USING VARIOUS COATING MATERIALS

    OpenAIRE

    Akshay Singh Thakur; Prof. Arun Pachori

    2017-01-01

    Pollution flashover is a critical problem which affects the safety of operation of power system. In order to prevent pollution flashover accidents of outdoor insulation devices, a series of anti-pollution coatings got application. Different alternatives are used to improve the behavior of the electrical insulation used in transmission lines and thus reduce or prevent the transmission line outages caused by pollution.

  19. Silanization of boron nitride nanosheets (BNNSs) through microfluidization and their use for producing thermally conductive and electrically insulating polymer nanocomposites

    Energy Technology Data Exchange (ETDEWEB)

    Seyhan, A.Tuğrul, E-mail: atseyhan@anadolu.edu.tr [Department of Materials Science and Engineering, Anadolu University - AU, Iki Eylul Campus, 26550 Eskisehir (Turkey); Composite Materials Manufacturing Science Laboratory (CMMSL), Research and Application Center of Civil Aviation (RACCA), Anadolu University - AU, Iki Eylul Campus, 26550 Eskisehir (Turkey); Göncü, Yapıncak; Durukan, Oya; Akay, Atakan; Ay, Nuran [Department of Materials Science and Engineering, Anadolu University - AU, Iki Eylul Campus, 26550 Eskisehir (Turkey)

    2017-05-15

    to make it possible to utilize them as promising filler constituent in manufacturing thermally conductive and electrically insulating polymer nanocomposites that could be considered as whole or a part of a heat-releasing device.

  20. Silanization of boron nitride nanosheets (BNNSs) through microfluidization and their use for producing thermally conductive and electrically insulating polymer nanocomposites

    Science.gov (United States)

    Seyhan, A. Tuğrul; Göncü, Yapıncak; Durukan, Oya; Akay, Atakan; Ay, Nuran

    2017-05-01

    to make it possible to utilize them as promising filler constituent in manufacturing thermally conductive and electrically insulating polymer nanocomposites that could be considered as whole or a part of a heat-releasing device.

  1. Insulation for crack protection of brick liners at Tucson Electric Power Company's Irvington Station

    Energy Technology Data Exchange (ETDEWEB)

    Bochicchio, V.A.; Hodder, T.; Olmsted, C.D.

    1986-04-01

    The chimney designed and constructed for Units 3 and 4 of the Irvington Generating Station Coal Conversion Project consists of a concrete shell with two acid-resistant brick liners. The liners incorporate an exterior layer of fiberglass insulation to reduce the temperature gradient through the brick wall and, hence, the tensile stresses in the brickwork. The reduction or elimination of cracking by means of insulation is expected to result in improved performance of the lining and reduced maintenance. This paper discusses the stresses involved, the usual crack development mechanism, stress testing background, and the Irvington Station brick liner insulation application.

  2. Health impacts due to personal exposure to fine particles caused by insulation of residential buildings in Europe

    Science.gov (United States)

    Gens, Alexandra; Hurley, J. Fintan; Tuomisto, Jouni T.; Friedrich, Rainer

    2014-02-01

    The insulation of residential buildings affects human exposure to fine particles. According to current EU guidelines, insulation is regulated for energy saving reasons. As buildings become tighter, the air exchange rate is reduced and, thus, the indoor concentration of pollutants is increased if there are significant indoor sources. While usually the effects of heat insulation and increase of the air-tightness of buildings on greenhouse gas emissions are highlighted, the negative impacts on human health due to higher indoor concentrations are not addressed. Thus, we investigated these impacts using scenarios in three European countries, i. e. Czech Republic, Switzerland and Greece. The assessment was based on modelling the human exposure to fine particles originating from sources of particles within outdoor and indoor air, including environmental tobacco smoke. Exposure response relationships were derived to link (adverse) health effects to the exposure. Furthermore, probable values for the parameters influencing the infiltration of fine particles into residential buildings were modelled. Results show that the insulation and increase of the air-tightness of residential buildings leads to an overall increase of the mean population exposure - and consequently adverse health effects - in all considered countries (ranging for health effects from 0.4% in Czech Republic to 11.8% in Greece for 100% insulated buildings) due to an accumulation of particles indoors, especially from environmental tobacco smoke. Considering only the emission reductions in outdoor air (omitting changes in infiltration parameters) leads to a decrease of adverse health effects. This study highlights the importance of ensuring a sufficient air exchange rate when insulating buildings, e. g. by prescribing heat ventilation and air conditioning systems in new buildings and information campaigns on good airing practice in renovated buildings. It also shows that assessing policy measures based on the

  3. Fatal cranial injuries caused by an electric angle grinder.

    Science.gov (United States)

    Telmon, N; Allery, J P; Scolan, V; Rougé, D

    2001-03-01

    A case of fatal cranial injuries caused by an angle grinder is reported. The scalp lesions were typical of those produced by a cutting disk in a side-slipping movement. On the cranial vault were two bony losses of substance, one of which was deep enough for intracranial penetration of the disk. Signs of deflection of the disk, identical to those found on the scalp, were observed on the external bony table. Because of the circumstances in which the victim was discovered, in particular the damage to the machine which had a broken handle, and the lack of any indication of homicide or suicide, an accident is the most likely hypothesis.

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

    Science.gov (United States)

    Izzati, Wan Akmal; Adzis, Zuraimy; Shafanizam, Mohd

    2014-01-01

    Polymer nanocomposites have recently been attracting attention among researchers in electrical insulating applications from energy storage to power delivery. However, partial discharge has always been a predecessor to major faults and problems in this field. In addition, there is a lot more to explore, as neither the partial discharge characteristic in nanocomposites nor their electrical properties are clearly understood. By adding a small amount of weight percentage (wt%) of nanofillers, the physical, mechanical, and electrical properties of polymers can be greatly enhanced. For instance, nanofillers in nanocomposites such as silica (SiO2), alumina (Al2O3) and titania (TiO2) play a big role in providing a good approach to increasing the dielectric breakdown strength and partial discharge resistance of nanocomposites. Such polymer nanocomposites will be reviewed thoroughly in this paper, with the different experimental and analytical techniques used in previous studies. This paper also provides an academic review about partial discharge in polymer nanocomposites used as electrical insulating material from previous research, covering aspects of preparation, characteristics of the nanocomposite based on experimental works, application in power systems, methods and techniques of experiment and analysis, and future trends. PMID:24558326

  5. Bilayers of Ni3C12S12 and Pt3C12S12: graphene-like 2D topological insulators tunable by electric fields

    Science.gov (United States)

    Silveira, Orlando J.; Lima, Érika N.; Chacham, Hélio

    2017-11-01

    In the present work we predict, through first-principles calculations, that bilayers of the recently synthesized Ni3 C12 S12 and Pt3 C12 S12 layered materials are topological insulators upon electron doping, and that their topological insulator properties can be modulated by the application of electric fields with magnitudes achievable in devices. The electronic structures of both bilayers are characterized by spin–orbit split graphene-like bands, with gap magnitudes that are three orders of magnitude larger than graphene’s. In ribbon geometries, chiral edge modes develop at each side with band dispersions similar to that of Kane–Mele graphene model. Surprisingly, the edge states’ spin-propagation locking occurs even for very thin ribbons. We also find that the response of the electronic structure of both materials to applied electric fields are similar to both graphene and the Kane–Mele model with a Rashba term. All these findings indicate that these bilayer systems can be considered as large-spin–orbit graphene analogues with a strong sensitivity to applied electric fields.

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

    Science.gov (United States)

    Dan, C.; Morar, R.

    2017-05-01

    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.

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

    KAUST Repository

    Ghoneim, Mohamed T.

    2015-06-01

    We report on the electrical study of high dielectric constant insulator and metal gate metal oxide semiconductor capacitors (MOSCAPs) on a flexible ultra-thin (25 μm) silicon fabric which is peeled off using a CMOS compatible process from a standard bulk mono-crystalline silicon substrate. A lifetime projection is extracted using statistical analysis of the ramping voltage (Vramp) breakdown and time dependent dielectric breakdown data. The obtained flexible MOSCAPs operational voltages satisfying the 10 years lifetime benchmark are compared to those of the control MOSCAPs, which are not peeled off from the silicon wafer. © 2014 IEEE.

  8. Ventricular oversensing of atrial electrical activity that inhibits VVI pacemaker and causes syncope

    Directory of Open Access Journals (Sweden)

    Elibet Chávez González

    2015-10-01

    Full Text Available Far-field oversensing of atrial electrical activity caused by a VVI pacemaker is a rare phenomenon; however, it may have serious clinical consequences. It has several causes and its timely identification may avoid a possible ventricular asystole. This article reports the case of a 72-year-old male who had a Biotronik Axios SR pacemaker implanted, in VVIR mode, six years ago, due to blocked atrial fibrillation. He suffered syncope due to pacemaker inhibition caused by ventricular oversensing of atrial electrical activity.

  9. Electrical transport properties and morphology of topological insulator Bi{sub 2}Se{sub 3} thin films with different thickness prepared by magnetron sputtering

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Min; Wei, Zhantao; Jin, Rong; Ji, Yaxin; Yan, Yong; Pu, Xiaoyan [Key Laboratory of Advanced Technology of Materials (Ministry of Education), Superconductivity and New Energy R& D Center, Mail Stop 165#, Southwest Jiaotong University, Chengdu, Sichuan 610031 (China); Yang, Xinsheng, E-mail: xsyang@swjtu.edu.cn [Key Laboratory of Advanced Technology of Materials (Ministry of Education), Superconductivity and New Energy R& D Center, Mail Stop 165#, Southwest Jiaotong University, Chengdu, Sichuan 610031 (China); Zhao, Yong [Key Laboratory of Advanced Technology of Materials (Ministry of Education), Superconductivity and New Energy R& D Center, Mail Stop 165#, Southwest Jiaotong University, Chengdu, Sichuan 610031 (China); School of Materials Science and Engineering, University of New South Wales, Sydney, 2052, NSW (Australia)

    2016-03-31

    Topological insulator Bi{sub 2}Se{sub 3} thin films were grown by magnetron sputtering on Si (1 0 0) substrate and their phase structures and electrical properties were studied. The films have good crystalline quality, and their surfaces exhibited terrace-like quintuple layers. In the high temperature region, contribution from surface carrier and bulk conduction band electrons excited from an impurity band; in the low temperature region, surface electron became dominant. The weak antilocalization (WAL) cusp was observed in the magneto-transport measurement at low temperature under low magnetic field. The linear magnetoresistance (MR) under high-field was found, which was associated with the gapless topological surface states and of quantum origin. Insulating tendency was much stronger in thinner films. The WAL effect became weaker in thicker films. The top surface was only partially decoupled. - Highlights: • The linear magnetoresistance is associated with gapless topological surface state. • Insulating tendency is much stronger in thinner films. • The weak antilocalization effect becomes weaker with increasing thickness.

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

    CERN Document Server

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

    2012-01-01

    In the framework of the European Union FP7 project EuCARD, two composite insulation systems made of cyanate ester epoxy mix and tri-functional epoxy (TGPAP-DETDA) with S-glass fiber have been thermally tested as possible candidates to be the electrical insulation of 13 T 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...

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

    Energy Technology Data Exchange (ETDEWEB)

    Thome, F.V.

    1978-04-01

    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.

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

    Science.gov (United States)

    Wang, Jingang; Chong, Junlong; Yang, Jie

    2014-10-01

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

  13. Forced cooling of underground electric power transmission lines. Part II. Heat conduction in the cable insulation of force-cooled underground electrical power transmission systems. Yearly report

    Energy Technology Data Exchange (ETDEWEB)

    Sanders, J.V.; Glicksman, L.R.; Rohsenow, W.M.

    1974-05-01

    Forced-cooled systems for oil-filled pipe-type cable circuits have recently been considered. In such systems the conduction resistance through the paper insulation of the cables is the limiting thermal resistance. Assuming bilateral symmetry, steady-state conditions, and two-dimensional heat transfer, a FORTRAN IV computer program was written to solve the heat conduction problem in the cable insulation for abritrary configurations of a three-cable system. For a steel pipe, a cable system is most susceptible to overheating in the equilateral configuration with the three cables touching. Proximity effects are very significant in forced cooling, especially when cables are not provided with a copper tape under the insulation moisture seal assembly, accounting for as much as 21 percent of the total oil temperature rise between refrigeration stations. This figure, however, is reduced to 8 percent when 0.005 in.-thick copper tape is present.

  14. A comparative study of Mg and Pt contacts on semi-insulating GaAs: electrical and XPS characterization

    Czech Academy of Sciences Publication Activity Database

    Dubecký, F.; Kindl, Dobroslav; Hubík, Pavel; Mičušík, M.; Dubecký, M.; Boháček, P.; Vanko, G.; Gombia, E.; Nečas, V.; Mudroň, J.

    2017-01-01

    Roč. 395, Feb (2017), s. 131-135 ISSN 0169-4332 Institutional support: RVO:68378271 Keywords : semi-insulating GaAs * metal-semiconductor contact * interface * work function * electron transport * XPS Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 3.387, year: 2016

  15. Effect of the Ignition Method on the Extinction Limit for a Flame Spreading over Electric Wire Insulation

    DEFF Research Database (Denmark)

    Mitsui, Fumiya; Nagachi, Masashi; Citerne, Jean-Marie

    Flame spread experiments with wire insulation were conducted in microgravity (parabolic flights) and in normal gravity to understand the effect of the ignition condition on the Limiting Oxygen Concentration (LOC) for an opposed air flow condition of 100 mm/s (typical flow velocity on ISS). Both t...

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

    CERN Document Server

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

    2002-01-01

    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.

  17. 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

    Energy Technology Data Exchange (ETDEWEB)

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

    2006-10-01

    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.

  18. Electrical failure during cardiopulmonary bypass: an evaluation of incidence, causes, management and guidelines for preventative measures.

    LENUS (Irish Health Repository)

    Hargrove, M

    2012-02-03

    The incidence of electrical failure during cardiopulmonary bypass (CPB) has been reported to occur in approximately 1 per 1000 cases. While the resultant morbidity and mortality is low, electrical failure is a life-threatening scenario. We report three major electrical failures during CPB in a patient population of 3500 over a 15-year period. These cases involved mains failure and generator shut down, mains failure and generator power surge, and failure of the uninterruptable power supply (UPS), which caused protected sockets to shut down. Protocols for preventative maintenance, necessary equipment, battery backup and guidelines for the successful management of such accidents during CPB are discussed.

  19. Insulator for laser housing

    Science.gov (United States)

    Duncan, David B.

    1992-01-01

    The present invention provides a heat-resistant electrical insulator adapted for joining laser housing portions, which insulator comprises: an annulus; a channel in the annulus traversing the circumference and length of the housing; at least two ports, each communicating with the channel and an outer surface of the housing; and an attachment for securely attaching each end of the annulus to a laser housing member.

  20. Insulation fact sheet

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1997-08-01

    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.

  1. Study on Insulating Material by Renewable Resources

    Science.gov (United States)

    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.

  2. Properties of radiation stable insulation composites for fusion magnet

    Science.gov (United States)

    Wu, Zhixiong; Huang, Rongjin; Huang, Chuanjun; Li, Laifeng

    2017-09-01

    High field superconducting magnets made of Nb3Al will be a suitable candidate for future fusion device which can provide magnetic field over 15T without critical current degradation caused by strain. The higher magnetic field and the larger current will produce a huge electromagnetic force. Therefore, it is necessary to develop high strength cryogenic structural materials and electrical insulation materials with excellent performance. On the other hand, superconducting magnets in fusion devices will experience significant nuclear radiation exposure during service. While typical structural materials like stainless steel and titanium have proven their ability to withstand these conditions, electrical insulation materials used in these coils have not fared as well. In fact, recent investigations have shown that electrical insulation breakdown is a limiting factor in the performance of high field magnets. The insulation materials used in the high field fusion magnets should be characterized by excellent mechanical properties, high radiation resistivity and good thermal conductivity. To meet these objectives, we designed various insulation materials based on epoxy resins and cyanate ester resins and investigated their processing characteristic and mechanical properties before and after irradiation at low temperature. In this paper, the recent progress of the radiation stable insulation composites for high field fusion magnet is presented. The materials have been irradiated by 60Co γ-ray irradiation in air at ambient temperature with a dose rate of 300 Gy/min. The total doses of 1 MGy, 5 MGy and 10 MGy were selected to the test specimens.

  3. "Train surfers": analysis of 23 cases of electrical burns caused by high tension railway overhead cables.

    Science.gov (United States)

    Sternick, I; Gomes, R D; Serra, M C; Radwanski, H N; Pitanguy, I

    2000-08-01

    The term "train surfers" describes a group of adolescents from the outskirts of the city of Rio de Janeiro, who are compelled by the overcrowded railway trains to travel on the roofs of the wagons. Collision with electrical high-tension wires is a relatively frequent occurrence, causing extensive and complex injuries. This study analyzes this clinical and surgical phenomenon which has caused over 100 fatalities in more than 200 registered accidents over the past 10 years.

  4. Temperature and electric field stabilities of dielectric and insulating properties for c-axis-oriented CaBi4Ti4O15 films

    Science.gov (United States)

    Kimura, Junichi; Takuwa, Itaru; Matsushima, Masaaki; Yasui, Shintaro; Yamada, Tomoaki; Funakubo, Hiroshi

    2013-07-01

    Temperature and electric field dependencies of the dielectric and insulating properties of (001)-oriented epitaxial CaBi4Ti4O15 films grown on (100)cSrRuO3//(100)SrTiO3 substrates were investigated and compared with those of conventional (100)-oriented epitaxial (Ba0.3Sr0.7)TiO3 and SrTiO3 films. All films showed negative temperature dependency of the capacitance from 25 to 500 °C, and their changes were -18%, -83%, and -58% for CaBi4Ti4O15, (Ba0.3Sr0.7)TiO3, and SrTiO3 films, respectively. Smaller change of the capacitance against dc electric field was also observed for CaBi4Ti4O15 films. Moreover, the maximum leakage current density of CaBi4Ti4O15 films measured at ±100 kV/cm was below 10-3 A/cm2 up to 500 °C, which was smaller than those of (Ba0.3Sr0.7)TiO3 and SrTiO3 films. These results indicate that (001)-oriented CaBi4Ti4O15 films are a useful candidate as the capacitor material applicable for the high temperature use because of its high stability against temperature and an electric field as well as the good insulating characteristics.

  5. [Cardiocirculatory arrest caused by electric shock: importance of semi-automatic defibrillator].

    Science.gov (United States)

    Siah, S; Fouadi, F E; Ababou, K; Ihrai, I; Drissi, N K

    2011-03-31

    Accidental electrical burn injuries are serious because they can cause death by cardiocirculatory arrest. Cardiocirculatory arrest induced by low-voltage current is generally due to ventricular fibrillation, and the prognosis is fairly good if the survival chain is efficient. It is necessary to give priority to early defibrillation using an automated external defibrillator. Early defibrillation can immediately restore spontaneous circulation.

  6. Modelling and assessment of the electric field strength caused by mobile phone to the human head

    Directory of Open Access Journals (Sweden)

    Buckus Raimondas

    2016-01-01

    Full Text Available Background/Aim. Electromagnetic field exposure is the one of the most important physical agents that actively affects live organisms and environment. Active use of mobile phones influences the increase of electromagnetic field radiation. The aim of the study was to measure and assess the electric field strength caused by mobile phones to the human head. Methods. In this paper the software “COMSOL Multiphysics” was used to establish the electric field strength created by mobile phones around the head. Results. The second generation (2G Global System for Mobile (GSM phones that operate in the frequency band of 900 MHz and reach the power of 2 W have a stronger electric field than (2G GSM mobile phones that operate in the higher frequency band of 1,800 MHz and reach the power up to 1 W during conversation. The third generation of (3G UMTS smart phones that effectively use high (2,100 MHz radio frequency band emit the smallest electric field strength values during conversation. The highest electric field strength created by mobile phones is around the ear, i.e. the mobile phone location. The strength of mobile phone electric field on the phantom head decreases exponentially while moving sidewards from the center of the effect zone (the ear, and constitutes 1-12% of the artificial head’s surface. Conclusion. The highest electric field strength values of mobile phones are associated with their higher power, bigger specific energy absorption rate (SAR and lower frequency of mobile phone. The stronger electric field emitted by the more powerful mobile phones takes a higher percentage of the head surface. The highest electric field strength created by mobile phones is distributed over the user ear.

  7. In situ electric fields causing electro-stimulation from conductor contact of charged human.

    Science.gov (United States)

    Nagai, Toshihiro; Hirata, Akimasa

    2010-08-01

    Contact currents flow from/into a human body when touching an object such as a metal structure with a different electric potential. These currents can stimulate muscle and peripheral nerves. In this context, computational analyses of in situ electric fields caused by the contact current have been performed, while their effectiveness for transient contact currents has not well been investigated. In the present study, using an anatomically based human model, a dispersive finite-difference time-domain model was utilised to computed transient contact current and in situ electric fields from a charged human. Computed in situ electric fields were highly localised in the hand. In order to obtain an insight into the relationship between in situ electric field and electro-stimulation, cell-maximum and 5-mm averaged in situ electric fields were computed and compared with strength-duration curves. The comparison suggests that both measures could be larger than thresholds derived from the strength-duration curves with parameters used in previous studies.

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

    Science.gov (United States)

    Kierczyński, Konrad; Żukowski, Paweł

    2016-12-01

    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.

  9. 13. SNPTEE: Brazilian seminar on electric power production and transmission. Group 11: overvoltage, insulation coordination and interferences (GSI); 13. SNPTEE: Seminario nacional de producao e transmissao de energia eletrica. Grupo 11: sobretensoes, coordenacao de isolamento e interferencias (GSI)

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1995-12-31

    This book collects the works presented during the 13{sup th} national seminar on electric power generation and transmission which took place in Camboriu, Santa Catarina State - South Brazil, in 1995. The Group 11 discussed over voltages, insulation coordination and interferences giving special emphasis to: electric power systems design, operation, controlling and optimization; as well as automation and safety systems. The existing situation in Brazil is presented and discussed as well as future trends and perspectives. Several case studies are presented

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

    National Research Council Canada - National Science Library

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

    2013-01-01

    .... 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...

  11. A comparative study of Mg and Pt contacts on semi-insulating GaAs: Electrical and XPS characterization

    Energy Technology Data Exchange (ETDEWEB)

    Dubecký, F., E-mail: elekfdub@savba.sk [Institute of Electrical Engineering, SAS, Dúbravská cesta 9, Bratislava, SK-84104 (Slovakia); Kindl, D.; Hubík, P. [Institute of Physics CAS, v.v.i., Cukrovarnická 10, CZ-16200 Prague (Czech Republic); Mičušík, M. [Polymer Institute, SAS, Dúbravská cesta 9, Bratislava, SK-84541 (Slovakia); Dubecký, M. [Department of Physics, Faculty of Science, University of Ostrava, 30. dubna 22, CZ-70103 Ostrava 1 (Czech Republic); Boháček, P.; Vanko, G. [Institute of Electrical Engineering, SAS, Dúbravská cesta 9, Bratislava, SK-84104 (Slovakia); Gombia, E. [IMEM-CNR, Parco area delle Scienze 37/A, Parma, I-43010 (Italy); Nečas, V. [Faculty of Electrical Engineering and Information Technology, SUT, Ilkovičova 3, Bratislava, SK-81219 (Slovakia); Mudroň, J. [Department of Electronics, Academy of Armed Forces, Demänová 393, Liptovský Mikuláš, SK-03106 (Slovakia)

    2017-02-15

    Highlights: • Explored were diodes with full-area low/high work function metal contacts on semi-insulating GaAs (S). • The Mg-S-Mg diode is promising for radiation detectors for its low high-field current. • The XPS analysis of Mg-S interface shows presence of MgO instead of Mg metal. - Abstract: We present a comparative study of the symmetric metal-SI GaAs-metal (M-S-M) diodes with full-area contacts on both device sides, in order to demonstrate the effect of contact metal work function in a straightforward way. We compare the conventional high work function Pt contact versus the less explored low work function Mg contact. The Pt-S-Pt, Mg-S-Mg and mixed Mg-S-Pt structures are characterized by the current-voltage measurements, and individual Pt-S and Mg-S contacts are investigated by the X-ray photoelectron spectroscopy (XPS). The transport measurements of Mg-S-Pt structure show a significant current decrease at low bias while the Mg-S-Mg structure shows saturation current at high voltages more than an order of magnitude lower with respect to the Pt-S-Pt reference. The phenomena observed in Mg-containing samples are explained by the presence of insulating MgO layer at the M-S interface, instead of the elementary Mg, as confirmed by the XPS analysis. Alternative explanations of the influence of MgO layer on the effective resistance of the structures are presented. The reported findings have potential applications in M-S-M sensors and radiation detectors based on SI GaAs.

  12. Electric double-layer transistor using layered iron selenide Mott insulator TI[Fe.sub.1.6][Se.sub.2

    National Research Council Canada - National Science Library

    Katase, Takayoshi; Hiramatsu, Hidenori; Kamiya, Toshio; Hosono, Hideo

    2014-01-01

    ... (AFM) insulating phases, and they have extremely high Neel transition temperatures. However, control of carrier doping into the parent AFM insulators has been difficult due to their intrinsic phase separation...

  13. TO STUDY AND ANALYSIS OF RTV SILICONE RUBBER INSULATOR OPERATED WITH VARIOUS TEMPERATURE

    OpenAIRE

    Dr. S. K. Mahobia

    2017-01-01

    The insulator are most important equipment in transmission Line, Distribution Line and electrical power plant. In this way the insulator are used with pin, insulator and pin are mounted on the frame, which is connected with the Grid power supply. The insulator has to separate of electrical power supply and structure, in this way we are used the high quality insulator.

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

    Directory of Open Access Journals (Sweden)

    Eun-Soo Park

    2013-01-01

    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.

  15. Cellulose Insulation

    Science.gov (United States)

    1980-01-01

    Fire retardant cellulose insulation is produced by shredding old newspapers and treating them with a combination of chemicals. Insulating material is blown into walls and attics to form a fiber layer which blocks the flow of air. All-Weather Insulation's founders asked NASA/UK-TAP to help. They wanted to know what chemicals added to newspaper would produce an insulating material capable of meeting federal specifications. TAP researched the query and furnished extensive information. The information contributed to successful development of the product and helped launch a small business enterprise which is now growing rapidly.

  16. Thermal insulator

    Energy Technology Data Exchange (ETDEWEB)

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

    1985-07-16

    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.

  17. Effect of decreasing electrical resistance in Characeae cell membranes caused by the flow of alternating current

    Directory of Open Access Journals (Sweden)

    Edward Śpiewla

    2014-01-01

    Full Text Available By means of the techniques of external electrodes and microelectrodes, it was found that evanescent flow of an alternating current through plasmalemma of Characeae cells neutralises oscillatory change in their electrical resistance and reversibly diminishes its value. This effect is particularly significant in the case of "high resistance cells", but it weakens with increasing temperature. The value of the estimated activation energy indicates that, after flow of the alternating current through the membrane, a rapid increase in the conductivity may be caused by an increase in conductivity of potassium channels. This result seems to support the hypothesis of electroconformational feedback.

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

    OpenAIRE

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

    2017-01-01

    Tin doped indium oxide (ITO) thin films are being used extensively as transparent conductors in several applications. In the present communication, we report the electrical transport in DC magnetron sputtered ITO thin films (prepared at 300 K and subsequently annealed at 673 K in vacuum for 60 minutes) in low temperatures (25-300 K). The low temperature Hall effect and resistivity measurements reveal that the ITO thin films are moderately dis-ordered (kFl∼1; kF is the Fermi wave vector and l ...

  19. Statistical and electrical properties of the conduction electrons of a metal nanosphere in the region of metal-insulator transition

    OpenAIRE

    Datsyuk, Vitaly V; Ivanytska, Iryna V

    2014-01-01

    Statistical and electrical properties of the conduction electrons of a silver or gold sphere with a radius from 1 to 2 nm are shown to differ drastically from the properties of electrons in a bulk metal sample. If the radius of a noble metal sphere decreases from 10 to 1 nm, its conductivity oscillates around the bulk metal value with increasing amplitude and drops at the 'magic’ numbers of electrons. These numbers are equal to 186, 198, 254, 338, 440, 556, 676, 832, 912, 1,284, 1,502, and 1,...

  20. Impedance Characterization of the Degradation of Insulating Layer Patterned on Interdigitated Microelectrode.

    Science.gov (United States)

    Lee, Gihyun; Kim, Sohee; Cho, Sungbo

    2015-10-01

    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.

  1. Electric-field-induced Skyrmion distortion and giant lattice rotation in the magnetoelectric insulator Cu2OSeO3.

    Science.gov (United States)

    White, J S; Prša, K; Huang, P; Omrani, A A; Zivković, I; Bartkowiak, M; Berger, H; Magrez, A; Gavilano, J L; Nagy, G; Zang, J; Rønnow, H M

    2014-09-05

    Uniquely in Cu2OSeO3, the Skyrmions, which are topologically protected magnetic spin vortexlike objects, display a magnetoelectric coupling and can be manipulated by externally applied electric (E) fields. Here, we explore the E-field coupling to the magnetoelectric Skyrmion lattice phase, and study the response using neutron scattering. Giant E-field induced rotations of the Skyrmion lattice are achieved that span a range of ∼25°. Supporting calculations show that an E-field-induced Skyrmion distortion lies behind the lattice rotation. Overall, we present a new approach to Skyrmion control that makes no use of spin-transfer torques due to currents of either electrons or magnons.

  2. Statistical and electrical properties of the conduction electrons of a metal nanosphere in the region of metal-insulator transition.

    Science.gov (United States)

    Datsyuk, Vitaly V; Ivanytska, Iryna V

    2014-01-01

    Statistical and electrical properties of the conduction electrons of a silver or gold sphere with a radius from 1 to 2 nm are shown to differ drastically from the properties of electrons in a bulk metal sample. If the radius of a noble metal sphere decreases from 10 to 1 nm, its conductivity oscillates around the bulk metal value with increasing amplitude and drops at the 'magic' numbers of electrons. These numbers are equal to 186, 198, 254, 338, 440, 556, 676, 832, 912, 1,284, 1,502, and 1,760, in agreement with various experimental data. We show that the conductivity and capacitance of a metal nanosphere can be changed by several orders of magnitude by adding or removing just a few electrons.

  3. Study of Temperature Distribution Along an Artificially Polluted Insulator String

    Science.gov (United States)

    Subba, Reddy B.; Nagabhushana, G. R.

    2003-04-01

    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.

  4. Effects Of Radiation On Insulators

    Science.gov (United States)

    Bouquet, Frank L.

    1988-01-01

    Report presents data on responses of electrically insulating thermosetting and thermoplastic polymers to radiation. Lowest-threshold-dose (LTD) levels and 25-percent-change levels presented for such properties as tensile strength and electrical resistivity. Data on radiation-induced outgassing also given.

  5. Automotive Insulation

    Science.gov (United States)

    1997-01-01

    Under a Space Act Agreement between Boeing North America and BSR Products, Space Shuttle Thermal Protection System (TPS) materials are now used to insulate race cars. BSR has created special TPS blanket insulation kits for use on autos that take part in NASCAR events, and other race cars through its nationwide catalog distribution system. Temperatures inside a race car's cockpit can soar to a sweltering 140 to 160 degrees, with the extreme heat coming through the engine firewall, transmission tunnel, and floor. It is common for NASCAR drivers to endure blisters and burns due to the excessive heat. Tests on a car insulated with the TPS material showed a temperature drop of some 50 degrees in the driver's cockpit. BSR-TPS Products, Inc. now manufactures insulation kits for distribution to race car teams around the world.

  6. Transformer insulation monitoring by optical sensing techniques

    Science.gov (United States)

    Uttamchandani, Deepak G.; Blue, Robert; Farish, O.

    1998-08-01

    High voltage transformers use paper to insulate the electrical windings present in the core which is then subsequently immersed in oil. In service, the temperature of the windings will increase to typically 80 degrees C. If the transformer is loaded to beyond its design ratings, the temperature can exceed 100 degrees C causing the cellulose chains in the paper to cleave at an accelerated rate, resulting in the degradation of mechanical strength and performance of the insulation. If unchecked, this can lead to catastrophic failure of the transformed and accompanying disruption to electricity supply and large economic losses to the operating utility. Furfuraldehyde (FFA) is a chemical by-product which is released into the oil by the thermal degradation of the paper winding. The concentration of FFA within the oil has been directly related to the condition of the paper insulation. We have developed absorbance and fluorescence optical techniques incorporating a novel FFA- sensitive material which we have invested at our laboratories. This material has been incorporated into a prototype portable optoelectronic instrument for the measurement of FFA at the site of the transformer. Results of experiments will be presented, and the implication of these results for condition monitoring of HV transformer will be discussed.

  7. Dirac-electron-mediated magnetic proximity effect in topological insulator/magnetic insulator heterostructures

    Science.gov (United States)

    Li, Mingda; Song, Qichen; Zhao, Weiwei; Garlow, Joseph A.; Liu, Te-Huan; Wu, Lijun; Zhu, Yimei; Moodera, Jagadeesh S.; Chan, Moses H. W.; Chen, Gang; Chang, Cui-Zu

    2017-11-01

    The possible realization of dissipationless chiral edge current in a topological insulator/magnetic insulator heterostructure is based on the condition that the magnetic proximity exchange coupling at the interface is dominated by the Dirac surface states of the topological insulator. Here we report a polarized neutron reflectometry observation of Dirac-electron-mediated magnetic proximity effect in a bulk-insulating topological insulator (B i0.2S b0.8)2 T e3 /magnetic insulator EuS heterostructure. We are able to maximize the proximity-induced magnetism by applying an electrical back gate to tune the Fermi level of topological insulator to be close to the Dirac point. A phenomenological model based on diamagnetic screening is developed to explain the suppressed proximity-induced magnetism at high carrier density. Our work paves the way to utilize the magnetic proximity effect at the topological insulator/magnetic insulator heterointerface for low-power spintronic applications.

  8. Hypercalcemic crisis and primary hyperparathyroidism: Cause of an unusual electrical storm.

    Science.gov (United States)

    Guimarães, Tatiana; Nobre Menezes, Miguel; Cruz, Diogo; do Vale, Sónia; Bordalo, Armando; Veiga, Arminda; Pinto, Fausto J; Brito, Dulce

    2017-12-01

    Hypercalcemia is a known cause of heart rhythm disorders, however its association with ventricular arrhythmias is rare. The authors present a case of a fifty-three years old male patient with a ischemic and ethanolic dilated cardiomyopathy, and severely reduced ejection fraction, carrier of cardiac resynchronization therapy (CRT) with cardioverter defibrillator (ICD), admitted in the emergency department with an electrical storm, with multiple appropriated ICD shocks, refractory to antiarrhythmic therapy. In the etiological investigation was documented severe hypercalcemia secondary to primary hyperparathyroidism undiagnosed until then. Only after the serum calcium level reduction ventricular tachycardia was stopped. Copyright © 2017 Sociedade Portuguesa de Cardiologia. Publicado por Elsevier España, S.L.U. All rights reserved.

  9. Development of insulating coatings for liquid metal blankets

    Energy Technology Data Exchange (ETDEWEB)

    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.

    1994-07-01

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

  10. A Method to have Multi-Layer Thermal Insulation Provide Damage Detection

    Science.gov (United States)

    Woodward, Stanley E.; Taylor, Bryant D.; Jones, Thomas W.; Shams, Qamar A.; Lyons, Frankel; Henderson, Donald

    2007-01-01

    Design and testing of a multi-layer thermal insulation system that also provides debris and micrometeorite damage detection is presented. One layer of the insulation is designed as an array of passive open-circuit electrically conductive spiral trace sensors. The sensors are a new class of sensors that are electrically open-circuits that have no electrical connections thereby eliminating one cause of failure to circuits. The sensors are powered using external oscillating magnetic fields. Once electrically active, they produce their own harmonic magnetic fields. The responding field frequency changes if any sensor is damaged. When the sensors are used together in close proximity, the inductive coupling between sensors provides a means of telemetry. The spiral trace design using reflective electrically conductive material provides sufficient area coverage for the sensor array to serves as a layer of thermal insulation. The other insulation layers are designed to allow the sensor s magnetic field to permeate the insulation layers while having total reflective surface area to reduce thermal energy transfer. Results of characterizing individual sensors and the sensor array s response to punctures are presented. Results of hypervelocity impact testing using projectiles of 1-3.6 millimeter diameter having speeds ranging from 6.7-7.1 kilometers per second are also presented.

  11. Auroral Substorms: Search for Processes Causing the Expansion Phase in Terms of the Electric Current Approach

    Science.gov (United States)

    Akasofu, Syun-Ichi

    2017-10-01

    Auroral substorms are mostly manifestations of dissipative processes of electromagnetic energy. Thus, we consider a sequence of processes consisting of the power supply (dynamo), transmission (currents/circuits) and dissipations (auroral substorms-the end product), namely the electric current line approach. This work confirms quantitatively that after accumulating magnetic energy during the growth phase, the magnetosphere unloads the stored magnetic energy impulsively in order to stabilize itself. This work is based on our result that substorms are caused by two current systems, the directly driven (DD) current system and the unloading system (UL). The most crucial finding in this work is the identification of the UL (unloading) current system which is responsible for the expansion phase. A very tentative sequence of the processes leading to the expansion phase (the generation of the UL current system) is suggested for future discussions. (1) The solar wind-magnetosphere dynamo enhances significantly the plasma sheet current when its power is increased above 10^{18} erg/s (10^{11} w). (2) The magnetosphere accumulates magnetic energy during the growth phase, because the ionosphere cannot dissipate the increasing power because of a low conductivity. As a result, the magnetosphere is inflated, accumulating magnetic energy. (3) When the power reaches 3-5× 10^{18} erg/s (3-5× 10^{11} w) for about one hour and the stored magnetic energy reaches 3-5×10^{22} ergs (10^{15} J), the magnetosphere begins to develop perturbations caused by current instabilities (the current density {≈}3× 10^{-12} A/cm2 and the total current {≈}106 A at 6 Re). As a result, the plasma sheet current is reduced. (4) The magnetosphere is thus deflated. The current reduction causes partial B/partial t > 0 in the main body of the magnetosphere, producing an earthward electric field. As it is transmitted to the ionosphere, it becomes equatorward-directed electric field which drives both

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

    Energy Technology Data Exchange (ETDEWEB)

    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)

    2013-11-15

    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.)

  13. Design and Simulation of an Anode Stalk Support Insulator

    CERN Document Server

    Wang, Lisa; Westenskow, Glen

    2005-01-01

    An anode stalk support insulator in a magnetically insulated transmission line was designed and modeled. One of the important design criteria is that within space constraints, the electric field along the insulator surface has to be minimized in order to prevent a surface flashover. In order to further reduce the field on the insulator surface, metal rings between insulator layers were also specially shaped. To facilitate the design process, electric field simulations were performed to determine the maximum field stress on the insulator surfaces and the transmission line chamber.

  14. Are Kondo insulators simply insulators?

    Energy Technology Data Exchange (ETDEWEB)

    Aeppli, G.; DiTusa, J.F. [AT& T Bell Laboratories, Murray Hill, NJ (United States); Fisk, Z. [Los Alamos National Laboratory, NM (United States)

    1994-12-31

    Since the discovery of the anomalous normal state properties of the high-T{sub c} oxides, there has been a lively debate concerning the applicability of conventional Fermi liquid theory to strongly interacting metals. A question arising naturally in this context is whether strongly interacting insulators exhibit properties at odds with ordinary band theory. Of course, Mott insulators, which in the absence of strong Coulomb interactions would be metals, represent the most dramatic breakdown of band theory. However, among strongly interacting insulators which one believes are band insulators, there have until recently been no indications that many-body effects yield observable consequences beyond those which band parameter renormalization might account for. The large number of recent theoretical papers on this renormalization for f-band materials, as well as the long struggle to achieve quantitative understanding of the band gap in as basic a semiconductor as Si, attest to the importance and difficulty of calculating renormalized band parameters for insulators. Also, the experience with Si clearly shows that the renormalization can depend on the quantity being measured. In a recent review, the authors placed the newly discovered Ce-based Kondo insulators, as well as older anomalous semiconductors such as SmB{sub 6} and FeSi, in the context of renormalized band theory. The conclusion was that in large measure, this theory represents an adequate starting point for understanding strongly correlated insulators. The goal here is not to repeat what was said before, but to focus on those aspects of charge and spin fluctuations which the band picture cannot obviously accomodate.

  15. Influence of damage caused by Kr ions and neutrons on electrical properties of silicon detectors

    CERN Document Server

    Croitoru, N; Rancoita, P G; Rattaggi, M; Seidman, A

    1999-01-01

    In this paper, new measurements of physical properties of high-resistivity silicon, used in high-energy detectors, are presented. The obtained data contribute to the understanding of the causes which damage the 2electronic characteristics of the detection systems under irradiation of neutrons and ionized particles (Kr). The Hall effect coefficient (R sub H) and resistivity (rho) measurements as a function of temperature (T), for non-irradiated and irradiated by neutrons and Kr ions, were performed. The measurements of the Hall coefficient and resistivity of non-irradiated samples and irradiated at neutron fluences (PHI=9.9x10 sup 1 sup 0 n/cm sup 2 (neutrons) and PHI>=7.5x10 sup 8 Kr/cm sup 3 (ions), cannot be explained, considering the usual theoretical relations. The results, obtained in these experiments, have shown a change of mechanism of conduction due to the damaged regions, where localized levels are created, which are the main cause of the deviation of the electrical characteristics of the detectors ...

  16. Nonlinear dynamic behaviors of permanent magnet synchronous motors in electric vehicles caused by unbalanced magnetic pull

    Science.gov (United States)

    Xiang, Changle; Liu, Feng; Liu, Hui; Han, Lijin; Zhang, Xun

    2016-06-01

    Unbalanced magnetic pull (UMP) plays a key role in nonlinear dynamic behaviors of permanent magnet synchronous motors (PMSM) in electric vehicles. Based on Jeffcott rotor model, the stiffness characteristics of the rotor system of the PMSM are analyzed and the nonlinear dynamic behaviors influenced by UMP are investigated. In free vibration study, eigenvalue-based stability analysis for multiple equilibrium points is performed which offers an insight in system stiffness. Amplitude modulation effects are discovered of which the mechanism is explained and the period of modulating signal is carried out by phase analysis and averaging method. The analysis indicates that the effects are caused by the interaction of the initial phases of forward and backward whirling motions. In forced vibration study, considering dynamic eccentricity, frequency characteristics revealing softening type are obtained by harmonic balance method, and the stability of periodic solution is investigated by Routh-Hurwitz criterion. The frequency characteristics analysis indicates that the response amplitude is limited in the range between the amplitudes of the two kinds of equilibrium points. In the vicinity of the continuum of equilibrium points, the system hardly provides resistance to bending, and hence external disturbances easily cause loss of stability. It is useful for the design of the PMSM with high stability and low vibration and acoustic noise.

  17. Topological quantum phase transition from mirror to time reversal symmetry protected topological insulator.

    Science.gov (United States)

    Mandal, Partha S; Springholz, Gunther; Volobuev, Valentine V; Caha, Ondrej; Varykhalov, Andrei; Golias, Evangelos; Bauer, Günther; Rader, Oliver; Sánchez-Barriga, Jaime

    2017-10-17

    Topological insulators constitute a new phase of matter protected by symmetries. Time-reversal symmetry protects strong topological insulators of the Z2 class, which possess an odd number of metallic surface states with dispersion of a Dirac cone. Topological crystalline insulators are merely protected by individual crystal symmetries and exist for an even number of Dirac cones. Here, we demonstrate that Bi-doping of Pb1-x Sn x Se (111) epilayers induces a quantum phase transition from a topological crystalline insulator to a Z2 topological insulator. This occurs because Bi-doping lifts the fourfold valley degeneracy and induces a gap at [Formula: see text], while the three Dirac cones at the [Formula: see text] points of the surface Brillouin zone remain intact. We interpret this new phase transition as caused by a lattice distortion. Our findings extend the topological phase diagram enormously and make strong topological insulators switchable by distortions or electric fields.Transitions between topological phases of matter protected by different symmetries remain rare. Here, Mandal et al. report a quantum phase transition from a topological crystalline insulator to a Z2 topological insulator by doping Bi into Pb1-x Sn x Se (111) thin films.

  18. Topological insulators

    CERN Document Server

    Franz, Marcel

    2013-01-01

    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

  19. Two modes of cell death caused by exposure to nanosecond pulsed electric field.

    Directory of Open Access Journals (Sweden)

    Olga N Pakhomova

    Full Text Available High-amplitude electric pulses of nanosecond duration, also known as nanosecond pulsed electric field (nsPEF, are a novel modality with promising applications for cell stimulation and tissue ablation. However, key mechanisms responsible for the cytotoxicity of nsPEF have not been established. We show that the principal cause of cell death induced by 60- or 300-ns pulses in U937 cells is the loss of the plasma membrane integrity ("nanoelectroporation", leading to water uptake, cell swelling, and eventual membrane rupture. Most of this early necrotic death occurs within 1-2 hr after nsPEF exposure. The uptake of water is driven by the presence of pore-impermeable solutes inside the cell, and can be counterbalanced by the presence of a pore-impermeable solute such as sucrose in the medium. Sucrose blocks swelling and prevents the early necrotic death; however the long-term cell survival (24 and 48 hr does not significantly change. Cells protected with sucrose demonstrate higher incidence of the delayed death (6-24 hr post nsPEF. These cells are more often positive for the uptake of an early apoptotic marker dye YO-PRO-1 while remaining impermeable to propidium iodide. Instead of swelling, these cells often develop apoptotic fragmentation of the cytoplasm. Caspase 3/7 activity increases already in 1 hr after nsPEF and poly-ADP ribose polymerase (PARP cleavage is detected in 2 hr. Staurosporin-treated positive control cells develop these apoptotic signs only in 3 and 4 hr, respectively. We conclude that nsPEF exposure triggers both necrotic and apoptotic pathways. The early necrotic death prevails under standard cell culture conditions, but cells rescued from the necrosis nonetheless die later on by apoptosis. The balance between the two modes of cell death can be controlled by enabling or blocking cell swelling.

  20. Translucent Insulation

    DEFF Research Database (Denmark)

    Rahbek, Jens Eg

    1998-01-01

    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....

  1. Kondo insulators

    Energy Technology Data Exchange (ETDEWEB)

    Fisk, Z.; Sarrao, J.L. [National High Magnetic Field Lab., Tallahassee, FL (United States); Thompson, J.D. [Los Alamos National Lab., NM (United States)

    1994-10-01

    The Kondo insulating materials present a particularly simple limiting case of the strongly correlated electron lattice problem: one occupied f-state interacting with a single half-filled conduction band. Experiment shows that the solution to this problem has some remarkably simple aspects. Optical conductivity data display the strong coupling nature of this physics.

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

    Directory of Open Access Journals (Sweden)

    Ye. D. Kim

    2009-03-01

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

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

    OpenAIRE

    Ye. D. Kim; V. H. Sychenko; V. L. Kalmykov

    2009-01-01

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

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

    OpenAIRE

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

    2013-01-01

    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...

  5. Improved insulator layer for MIS devices

    Science.gov (United States)

    Miller, W. E.

    1980-01-01

    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.

  6. Analysis of thermal performance of penetrated multi-layer insulation

    Science.gov (United States)

    Foster, Winfred A., Jr.; Jenkins, Rhonald M.; Yoo, Chai H.; Barrett, William E.

    1988-01-01

    Results of research performed for the purpose of studying the sensitivity of multi-layer insulation blanket performance caused by penetrations through the blanket are presented. The work described in this paper presents the experimental data obtained from thermal vacuum tests of various penetration geometries similar to those present on the Hubble Space Telescope. The data obtained from these tests is presented in terms of electrical power required sensitivity factors referenced to a multi-layer blanket without a penetration. The results of these experiments indicate that a significant increase in electrical power is required to overcome the radiation heat losses in the vicinity of the penetrations.

  7. Evidence that dirty electricity is causing the worldwide epidemics of obesity and diabetes.

    Science.gov (United States)

    Milham, Samuel

    2014-01-01

    The epidemics of obesity and diabetes most apparent in recent years had their origins with Thomas Edison's development of distributed electricity in New York City in 1882. His original direct current (DC) generators suffered serious commutator brush arcing which is a major source of high-frequency voltage transients (dirty electricity). From the onset of the electrical grid, electrified populations have been exposed to dirty electricity. Diesel generator sets are a major source of dirty electricity today and are used almost universally to electrify small islands and places unreachable by the conventional electric grid. This accounts for the fact that diabetes prevalence, fasting plasma glucose and obesity are highest on small islands and other places electrified by generator sets and lowest in places with low levels of electrification like sub-Saharan Africa and east and Southeast Asia.

  8. RESEARCH OF THE INFLUENCE OF VARIOUS FACTORS ON THE ACCURACY OF DETERMINING OF PARAMETERS AND PLACE OF INSULATION DAMAGE IN THE ELECTRIC NETWORKS OF 6 TO 35 KV

    Directory of Open Access Journals (Sweden)

    Naraeva R.R

    2013-12-01

    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.

  9. Improved Thermal-Insulation Systems for Low Temperatures

    Science.gov (United States)

    Fesmire, James E.; Augustynowicz, Stanislaw D.

    2003-01-01

    Improved thermal-insulation materials and structures and the techniques for manufacturing them are undergoing development for use in low-temperature applications. Examples of low-temperature equipment for which these thermal insulation systems could provide improved energy efficiency include storage tanks for cryogens, superconducting electric-power-transmission equipment, containers for transport of food and other perishable commodities, and cold boxes for low-temperature industrial processes. These systems could also be used to insulate piping used to transfer cryogens and other fluids, such as liquefied natural gas, refrigerants, chilled water, crude oil, or low-pressure steam. The present thermal-insulation systems are layer composites based partly on the older class of thermal-insulation systems denoted generally as multilayer insulation (MLI). A typical MLI structure includes an evacuated jacket, within which many layers of radiation shields are stacked or wrapped close together. Low-thermal-conductivity spacers are typically placed between the reflection layers to keep them from touching. MLI can work very well when a high vacuum level (less than 10(exp-4) torr) is maintained and utmost care is taken during installation, but its thermal performance deteriorates sharply as the pressure in the evacuated space rises into the soft vacuum range [pressures greater than 0.1 torr (greater than 13 Pa)]. In addition, the thermal performance of MLI is extremely sensitive to mechanical compression and edge effects and can easily decrease from one to two orders of magnitude from its ideal value even when the MLI is kept under high vacuum condition. The present thermal-insulation systems are designed to perform well under soft vacuum level, in particular the range of 1 to 10 torr. They are also designed with larger interlayer spacings to reduce vulnerability to compression (and consequent heat leak) caused by installation and use. The superiority of these systems is the

  10. Is the illite group the cause of high electrical conductivityin certain lithospheric areas?

    Directory of Open Access Journals (Sweden)

    M. Muschietti

    1998-06-01

    Full Text Available This article discusses the problem of the mineralogical-petrographic interpretation of the "anomalous" conductive layer inside the lithosphere, which has resulted from electromagnetic deep soundings. Three situations can be found: 1 a resistivity of less than 1 ? ·m in the Very High Conductivity Layer (VHCL; 2 a resistivity of 1÷100 ? ·m in the High Conductivity Layer (HCL; 3 a resistivity of 102 ÷ 103 ? ·m in the Continental Lower Crust (CLC. We have focused our attention on the HCL because of its widespread distribution. Most authors attribute HCL conductivity to the presence of salt water or graphitic materials, that are uniformly and continuously distributed inside rocks. Other hypotheses from the literature are the presence of oxides and/or sulphides, rock melting, and brine-bearing rocks. Each one of these elements can cause high electrical conductivity, depending on the petrophysical conditions, but much discussion involves the necessary physical continuity of the conductive elements. We forward one more hypothesis as follows. By means of experiments on rock samples from different geographical and deep areas, under simulated in situ physical conditions (e.g., pressure, temperature, saturation, we have found resistivity values similar to the in situ ones. Chemical, mineralogical, and petrographic analyses have shown the presence of large amounts of phyllosilicate minerals, such as illite. These minerals act in two ways: they produce the physical continuity of associated conductive minerals, and they decrease the resistivity of rocks. This second hypothesis is consistent with both the very widespread diffusion of illite inside the Earth's crust, and with the good conductivity found in depth.

  11. Determination of copper in liquid and solid insulation for large electrical equipment by ICP-OES. Application to copper contamination assessment in power transformers.

    Science.gov (United States)

    Bruzzoniti, Maria Concetta; De Carlo, Rosa Maria; Sarzanini, Corrado; Maina, Riccardo; Tumiatti, Vander

    2012-09-15

    Copper is one of the main constituents of the components in power transformers and its presence both in liquid (mineral oil) and in solid (Kraft paper) insulators can lead to enhanced dielectric losses and to the subsequent deterioration of their insulating properties. Recently the latter have been correlated to plant failures which in turn may have severe impact on the environment. This paper describes the direct analysis of copper in insulating mineral oil by ICP-OES and how it was first optimized compared to the official American Society for Testing and Materials (ASTM) D7151 method. Detection and quantification limits of 8.8 μg kg(-1) and 29.3 μg kg(-1) were obtained. Secondly, copper determination was improved by coupling a microwave assisted dissolution procedure of the mineral oil which avoided the problems, in the real samples, due to the presence of solid species of copper which cannot be nebulized following traditional methods described in literature. Sixteen mineral insulating oils sampled from transformers in service were analyzed before and after dissolution. In order to evaluate copper speciation, size fractionation was performed by filtration on PTFE filters (0.45, 1 and 5 μm). This test was performed on all the oil samples. Finally, because of the key role of the solid insulator in failed transformers, the Authors applied the developed method to study the copper deposition tendency onto the insulating Kraft paper tapes exerted by two unused oils (a corrosive and a non-corrosive one) under defined ageing conditions. Copyright © 2012 Elsevier B.V. All rights reserved.

  12. On vacuum-insulated thermal storage

    Energy Technology Data Exchange (ETDEWEB)

    Fuchs, Benjamin [Georg-Simon-Ohm Univ. of Applied Sciences, Nuernberg (Germany); Technische Univ. Muenchen (Germany). Inst. of Resource and Energy Technology; Hofbeck, Klaus [Georg-Simon-Ohm Univ. of Applied Sciences, Nuernberg (Germany)

    2011-07-01

    Nowadays, the insulation for thermal energy storage (TES) is not as good as it should be. One reason for this is the higher investment cost for better insulation. Nevertheless, most of the recent studies show that the thermal losses of long-term storage have been underestimated. Therefore, recent research studies have focused on vacuum-insulated thermal storage. There are two common concepts with regard to the use of vacuum insulation for thermal storage. On the one hand, the Center for Applied Energy Research (ZAE) in Munich uses an evacuated double vessel filled with pearlite. On the other hand, the Ohm University uses vacuum insulation panels (VIP). Both the insulation concepts are based on the Knudsen effect. Thus, the thermal conductivity is lowered by a factor of 6-10, when compared with the conventional insulation materials, such as EPS, XPS, or mineral wool. Both the concepts are adoptions of the existing insulation applications. The filled double vessel tank is already being used for cryogenic storage for liquid gases. Furthermore, VIPs are being used to insulate passive houses. However, the use of vacuum insulation for thermal energy storage causes different problems due to higher temperatures and moisture. Nevertheless, vacuum insulations are a promising solution for small thermal long-tenn storage. This study presents the first state-of-the-art review on vacuum-insulated thermal tanks.

  13. Comparative Investigation of Pollution Accumulation and Natural Cleaning for Different HV Insulators

    Directory of Open Access Journals (Sweden)

    M. Dimitropoulou

    2015-04-01

    Full Text Available High Voltage insulators are scattered throughout any HV network and a single insulator fault may cause an excessive outage. Reliability is a key issue for electric power systems and fault-free performance of insulators greatly reflects on the reliability of the system. Environmental influence is rather important for the optimum selection of outdoor insulators and, therefore, field measurements provide valuable information. Utilities perform such measurements in order to decide upon the location/route of new HV installations (substations, lines etc and also to optimize the selection, maintenance and replacement of already installed insulators. A rather interesting case in Greek territory is the island of Crete, due to the coastal development of the network and the local weather conditions. The Greek utility has employed a variety of remedies to cope with the pollution problem. Following the positive feedback after the installation on certain tower in the past, a large project to replace all ceramic insulators with new polymer ones of hydrophobic surface is now in progress. Polymer coatings have also been extensively applied on substations and also on certain areas/towers of the transmission network in the past. In order to investigate the pollution accumulation and the impact of natural washing on different insulator types, a series of periodical ESDD and NSDD pollution measurements were conducted in HEDNO’s TALOS High Voltage Test Station for a 3-months period. Multiple measurements were performed on each insulator every month in order to collect additional data. Five different insulators were selected based on the types historically used in the Cretan Network. Along with the standard glass disc profile, two strings of glass fog profile (the one coated with RTV and two long-rod composite insulators of different shed profile and material were used. Results are presented and discussed in this paper.

  14. Losses in electric motors caused by harmonics; Harmoniske overtoners betydning for tabene i elmotorer

    Energy Technology Data Exchange (ETDEWEB)

    Johansson, M. [Dansk Energi Analyse A/S, Glostrup (Denmark); Kehr, J.M. [ABB A/S, Skovlunde (Denmark); Hoejte Hansen, H. [Balslev A/S, Glostrup (Denmark)

    2012-03-15

    The purpose of the project was to provide evidence of power saving based on measurements in electric installations, in which the harmonics were reduced by active filters. The project has included knowledge building on the basis of literature and discussions with a Swedish and a Belgian producer of active filters. In connection with the project, tests have been made on a production line at the firm of Faerch Plast, where the distortion from the harmonics, measured as THDU, was 6 to 7 %. Measurements during two days with the active filter switched on and off with an interval of 10 minutes showed a very small difference in power input in the two situations. The power was 2.7 kW higher with connected filter than without filter. As the own consumption of the filter was 5.8 kW, the consumption of the installation itself was 3.1 kW lower, equal to 1 % of the load of the directly supplied induction motors. As a consequence of the very small differences, measured at Faerch Plast, it was decided to transfer the further work to a laboratory in order to measure under so controlled circumstances as possible. Measurements have been taken at KME (Copenhagen School of Marine Engineering and Technology Management) and at TI (Danish Technological Institute). The result of measurements on a 5.5 kW induction motor with a distortion from the harmonics (THDU) of 2.65 % shows no significant change in the input power compared to the situation with almost no distortion. Neither, it appears, is there a significant difference in the motor losses in a situation, where the measurement was taken with two rather distorted mains voltages with a THDU of 6.33 % and 7.66 %, respectively. Calculations on the basis of the equivalent diagram of the motor show that the additional motor losses in a 5.5 kW motor as a consequence of 5. harmonics of 5 % of the mains voltage (THDU 5 %) only is 2 W, while an experimentally derived formula results in a difference of approx 9 W or 0.2 % of the rated power of

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

    CERN Document Server

    International Electrotechnical Commission. Geneva

    1990-01-01

    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.

  16. Sizing of electric power transmission lines insulation in areas of vegetation burns occurrences; Dimensionamento do isolamento de LT`s em regioes de queimadas

    Energy Technology Data Exchange (ETDEWEB)

    Fonseca, J.R.; Tan, A.L. [CEPEL, Rio de Janeiro, RJ (Brazil); Junqueira, W.S. [Companhia Energetica de Sao Paulo, SP (Brazil); Silva, R.P [ELETROSUL, Curitiba, PR (Brazil); Assuncao, L.A.R. [Furnas, Rio de Janeiro, RJ (Brazil); Melo, M.O.C. [Companhia Hidro Eletrica do Sao Francisco (CHESF), Recife, PE (Brazil); Monassi, V.

    1987-12-31

    This work presents, for several voltages levels used in Brazil, the insulation requirements in order to prevent the occurrence of failures during vegetation burns. The work is based on field tests. The methodology developed is presented as well as the results 5 refs., 2 figs., 14 tabs.

  17. ITER CENTRAL SOLENOID COIL INSULATION QUALIFICATION

    Energy Technology Data Exchange (ETDEWEB)

    Martovetsky, N N; Mann, T L; Miller, J R; Freudenberg, K D; Reed, R P; Walsh, R P; McColskey, J D; Evans, D

    2009-06-11

    An insulation system for ITER Central Solenoid must have sufficiently high electrical and structural strength. Design efforts to bring stresses in the turn and layer insulation within allowables failed. It turned out to be impossible to eliminate high local tensile stresses in the winding pack. When high local stresses can not be designed out, the qualification procedure requires verification of the acceptable structural and electrical strength by testing. We built two 4 x 4 arrays of the conductor jacket with two options of the CS insulation and subjected the arrays to 1.2 million compressive cycles at 60 MPa and at 76 K. Such conditions simulated stresses in the CS insulation. We performed voltage withstand tests and after end of cycling we measured the breakdown voltages between in the arrays. After that we dissectioned the arrays and studied micro cracks in the insulation. We report details of the specimens preparation, test procedures and test results.

  18. Unconventional Fermi surface in an insulating state

    Energy Technology Data Exchange (ETDEWEB)

    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)

    2015-07-17

    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.

  19. Insulation systems for superconducting transmission cables

    DEFF Research Database (Denmark)

    Tønnesen, Ole

    1996-01-01

    This paper describes shortly the status of superconducting transmission lines and assesses what impact the recently discovered BSCCO superconductors may have on the design of the cables.Two basically different insulation systems are discussed:1) The room temperature dielectric design, where...... 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...

  20. Analysis of electrical properties of insulators (Si{sub 3}N{sub 4}, SiO{sub 2}, AlN, and Al{sub 2}O{sub 3})/0.5 nm Si{sub 3}N{sub 4}/AlGaN/GaN heterostructures

    Energy Technology Data Exchange (ETDEWEB)

    Maeda, Narihiko; Hiroki, Masanobu; Watanabe, Noriyuki; Oda, Yasuhiro; Yokoyama, Haruki; Enoki, Takatomo; Kobayashi, Takashi [NTT Photonics Laboratories, NTT Corporation, 3-1 Morinosato Wakamiya, Atsugi, Kanagawa 243-0198 (Japan); Yagi, Takuma [NTT Advanced Technology Corporation, 3-1 Morinosato Wakamiya, Atsugi, Kanagawa 243-198 (Japan); Makimoto, Toshiki [NTT Basic Research Laboratories, NTT Corporation, 3-1 Morinosato Wakamiya, Atsugi, Kanagawa 243-0198 (Japan)

    2007-06-15

    The electrical properties in AlGaN/GaN heterostructures with Si- and Al-based insulators (Si{sub 3}N{sub 4}, SiO{sub 2}, AlN, and Al{sub 2}O{sub 3}) have been examined and analyzed. By insulators deposition, significant increase in the two-dimensional electron gas (2DEG) density (N{sub s}) was observed with the order of N{sub s}(Al{sub 2}O{sub 3})>N{sub s}(AlN){proportional_to}N{sub s}(SiO{sub 2})>N{sub s}(Si{sub 3}N{sub 4})>N{sub 0} (N{sub 0}: N{sub s} without insulators). As the result, the decrease in the sheet resistance (R) was observed; the smallest order of R was R(Al{sub 2}O{sub 3})insulator). The insulators deposition effect has thus been shown to be significant and different among insulators. The increase in N{sub s} was analyzed in terms of the change in the potential profile, and the observed differences in N{sub s} among insulators have been interpreted. The band engineering including insulators is indispensable in understanding and designing AlGaN/GaN HFETs, since insulators are commonly used for the surface passivation as well as for the gate insulators, and the insulators deposition is to alter the essential device parameters such as the source resistance. (copyright 2007 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  1. Insulator coating for high temperature alloys method for producing insulator coating for high temperature alloys

    Science.gov (United States)

    Park, Jong Hee

    1998-01-01

    A method for fabricating an electrically insulating coating on a surface is disclosed comprising coating the surface with a metal, and reacting the metal coated surface with a nonmetal so as to create a film on the metal-coated surface. Alternatively, the invention provides for a method for producing a noncorrosive, electrically insulating coating on a surface saturated with a nonmetal comprising supplying a molten fluid, dissolving a metal in the molten fluid to create a mixture, and contacting the mixture with the saturated surface. Lastly, the invention provides an electrically insulative coating comprising an underlying structural substrate coated with an oxide or nitride compound

  2. Corrugated outer sheath gas-insulated transmission line

    Science.gov (United States)

    Kemeny, George A.; Cookson, Alan H.

    1981-01-01

    A gas-insulated transmission line includes two transmission line sections each of which are formed of a corrugated outer housing enclosing an inner high-voltage conductor disposed therein, with insulating support means supporting the inner conductor within the outer housing and an insulating gas providing electrical insulation therebetween. The outer housings in each section have smooth end sections at the longitudinal ends thereof which are joined together by joining means which provide for a sealing fixed joint.

  3. 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

    Energy Technology Data Exchange (ETDEWEB)

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

    1996-09-01

    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.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2017-01-01

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

  5. Deposition and characterization of amorphous aluminum nitride thin films for a gate insulator

    Energy Technology Data Exchange (ETDEWEB)

    Oikawa, H.; Akiyama, R. [Institute of Materials Science, University of Tsukuba,1-1-1 Tennoudai, Tsukuba, 305-8573 (Japan); Tsukuba Nano-Tech Human Resource Development Program, Graduate School of Pure and Applied Sciences, University of Tsukuba, 1-1-1 Tennoudai, Tsukuba, 305-8571 (Japan); Kanazawa, K. [Institute of Materials Science, University of Tsukuba,1-1-1 Tennoudai, Tsukuba, 305-8573 (Japan); Kuroda, S., E-mail: kuroda@ims.tsukuba.ac.jp [Institute of Materials Science, University of Tsukuba,1-1-1 Tennoudai, Tsukuba, 305-8573 (Japan); Tsukuba Nano-Tech Human Resource Development Program, Graduate School of Pure and Applied Sciences, University of Tsukuba, 1-1-1 Tennoudai, Tsukuba, 305-8571 (Japan); Harayama, I. [Institute of Applied Physics, University of Tsukuba, 1-1-1 Tennoudai, Tsukuba, 305-8573 (Japan); Tsukuba Nano-Tech Human Resource Development Program, Graduate School of Pure and Applied Sciences, University of Tsukuba, 1-1-1 Tennoudai, Tsukuba, 305-8571 (Japan); Nagashima, K. [Institute of Applied Physics, University of Tsukuba, 1-1-1 Tennoudai, Tsukuba, 305-8573 (Japan); Sekiba, D. [Institute of Applied Physics, University of Tsukuba, 1-1-1 Tennoudai, Tsukuba, 305-8573 (Japan); Tandem Accelerator Complex, Research Facility Center for Science and Technology, University of Tsukuba, 1-1-1 Tennoudai, Tsukuba, 305-8577 (Japan); Ashizawa, Y.; Tsukamoto, A.; Nakagawa, K. [College of Science and Technology, Nihon University, 7-24-1 Narashinodai, Funabashi, 274-8501 (Japan); Ota, N. [Tsukuba Nano-Tech Human Resource Development Program, Graduate School of Pure and Applied Sciences, University of Tsukuba, 1-1-1 Tennoudai, Tsukuba, 305-8571 (Japan)

    2015-01-01

    Thin films of aluminum nitride (AlN) fabricated by reactive deposition were characterized in order to examine the electrical insulation properties suitable for a gate insulator. For a series of AlN films deposited with a variation of the amount of Al flux at a fixed N flux, compositional and chemical analyses were performed using X-ray photoelectron spectroscopy (XPS) and elastic recoil detection analysis (ERDA). Combined with the result of current-voltage (I-V) measurement, it is found that the insulation properties are correlated with the compositional ratio between Al and N estimated by the ERDA measurement; a good electrical insulation with a minimal leak current of the order of 10{sup -9} A/cm{sup 2} at a high electric field 1 MV/cm is achieved in the film of nearly stoichiometric compositional ratio of Al/N, in which the dominance of the Al-N bonding state is confirmed in the XPS measurement. On the other hand, the incorporation of oxygen, probably caused by the surface oxidization due to the exposure to the air, has little effect on the electrical properties. - Highlights: • AlN thin films deposited by reactive deposition were characterized for gate insulator. • A good electrical insulation was achieved at nearly stoichiometric composition. • The effects of oxygen incorporation and Al-N bonding state were also investigated. • A minimum leak current density as low as 10{sup -9}A/cm{sup 2} at 1MV/cm was achieved.

  6. RELAXATIONS LOSSES IN POLYETHYLENE INSULATION OF COAXIAL CABLE STRUCTURE DURING AGING IN HIGH HUMIDITY CONDITIONS

    Directory of Open Access Journals (Sweden)

    G.V. Bezprozvannych

    2016-05-01

    Full Text Available Introduction. The presence of free moisture in power cables leading to the formation of tree structures - water treeing, which originate in the amorphous phase polyethylene and are a major cause of degradation of the polymer insulation. They represent the damage of the polymer size from several microns to 1 mm, developing technology for insulation defects under the combined action of the electric field and the moisture diffusing from the environment. Water treeing destroys the polymer chain, resulting in the formation of microcavities filled with moisture. The dynamics of water treeing and subtle properties largely depend on the composition, morphology of the polymer insulation, chemical nature of the defect, in which they originate. Due to the force of gravity in the water formed typical only for her region with locally ordered structure - clusters, which cause loss of relaxation. Purpose. Features presence of relaxation losses in high-frequency range in polyethylene insulation during aging in high humidity conditions of samples power and RF cables. Methodology. Samples of the power cable for the voltage of 35 kV with a cross-linked polyethylene insulation radial water-blocking protection from moisture and radio-frequency coaxial cable with thermoplastic insulation for 1440 hours in a humidity of 100%. The dielectric loss tangent measured resonance method before and after aging. Originality. Experimentally found evidence of the existence in the polymer cable insulation free water in the form of areas with locally ordered structure - clusters. It is found that the solid polyethylene insulation in the frequency dependence of dielectric loss tangent maximum relaxation shown one at 10 MHz in the initial state, and there are two additional frequency range 500 kHz - 5 MHz after moistening. For cross-linked polyethylene insulation characteristic of large width Δf of the frequency spectrum in which the observed relaxation losses. It is obvious that

  7. Electric polarization of He II caused by second and first sound

    Science.gov (United States)

    Adamenko, I. N.; Nemchenko, E. K.

    2017-09-01

    It is shown that in a three-component gas of superfluid helium (He II) quasiparticles made up of phonons, rotons, and quantized vortex rings (QVR), equilibrium is established instantaneously on experimental time scales. This results in the formation of a common normal component which can move relative to the superfluid component with a velocity w. When a velocity w is present, an electric field develops in the He II that has been observed experimentally. The reasons for this are an anisotropic dependence of the QVR energy on its momentum when w is present and the existence of a QVR dipole moment. The case where the dipole moment of a QVR is made up of its intrinsic dipole moment plus the dipole moment created by an external field is considered. The problem of the electric potential in a standing wave of second sound in a constant external electric field is solved. The electric potentials in a first sound wave owing to the flexoelectric effect, acceleration of the liquid, and an external electric field are obtained. These formulas are used in numerical calculations for comparing theory and experiments, and they can stimulate the setting up of new experiments.

  8. The impact of large structural brain changes in chronic stroke patients on the electric field caused by transcranial brain stimulation

    DEFF Research Database (Denmark)

    Minjoli, Sena; Saturnino, Guilherme B.; Blicher, Jakob Udby

    2017-01-01

    . Realistic head models containing large cortical and subcortical stroke lesions in the right parietal cortex were created using MR images of two patients. For TMS, the electric field of a double coil was simulated using the finite-element method. Systematic variations of the coil position relative...... to the lesion were tested. For TDCS, the finite-element method was used to simulate a standard approach with two electrode pads, and the position of one electrode was systematically varied. For both TMS and TDCS, the lesion caused electric field " hot spots" in the cortex. However, these maxima were...... aimed to characterize the impact of these changes on the spatial distribution of the electric field generated by both TBS methods. In addition to confirming the safety of TBS in the presence of large stroke-related structural changes, our aim was to clarify whether targeted stimulation is still possible...

  9. The impact of large structural brain changes in chronic stroke patients on the electric field caused by transcranial brain stimulation

    DEFF Research Database (Denmark)

    Minjoli, Sena; Saturnino, Guilherme B.; Blicher, Jakob Udby

    2017-01-01

    aimed to characterize the impact of these changes on the spatial distribution of the electric field generated by both TBS methods. In addition to confirming the safety of TBS in the presence of large stroke-related structural changes, our aim was to clarify whether targeted stimulation is still possible....... Realistic head models containing large cortical and subcortical stroke lesions in the right parietal cortex were created using MR images of two patients. For TMS, the electric field of a double coil was simulated using the finite-element method. Systematic variations of the coil position relative...... to the lesion were tested. For TDCS, the finite-element method was used to simulate a standard approach with two electrode pads, and the position of one electrode was systematically varied. For both TMS and TDCS, the lesion caused electric field " hot spots" in the cortex. However, these maxima were...

  10. CaSiO3 Perovskite May Cause Electrical Conductivity Jump in the Topmost Lower Mantle

    Science.gov (United States)

    Fei, Hongzhan; Huang, Rong; Yang, Xiaozhi

    2017-10-01

    The electrical conductivity of CaSiO3 perovskite was measured in situ between 17-24 GPa and 1300-2000 K using a multianvil apparatus and Solartron 1260 Impedance/Gain-Phase Analyzer in the frequency range of 107-1 Hz. The activation energies are 95-100 and 100-120 kJ/mol, and the activation volumes are 0.06 ± 0.08 and -0.46 ± 0.03 cm3/mol, at 1300-1800 and 1800-2000 K, respectively. Conduction under lower mantle conditions may be dominated by the ionic diffusion of oxygen. The electrical conductivity of CaSiO3 perovskite is higher than that of bridgmanite, majoritic garnet, and ferropericlase, the main constituents of the topmost lower mantle. Therefore, CaSiO3-perovsktie may significantly contribute to the electrical structure of the topmost lower mantle in spite of its relatively small volume proportion.

  11. Fiber glass plastic insulation of power transmission lines. Stekloplastikovaya izolyatsiya liniy elektroperedachi

    Energy Technology Data Exchange (ETDEWEB)

    Aleksandrov, G.N.; Ivanov, V.L.

    1983-01-01

    Results are described of comprehensive studies of electrophysical characteristics of polymer electrical insulation of external design under the main operating effects. The current state of the problem of creation, use and selection of polymer electrical insulation are presented. Fundamentals are presented of the technique of selecting the polymer electrical insulation taking into consideration the specific nature of the fiber glass plastic structure. A technique is developed for calculation and selection of screen fittings for fiber glass plastic electrical insulation designs for apparatus and overhead lines. Reference data are presented which can be used in calculating the fiber glass plastic electrical insulation.

  12. Assessment of the risk of failure of high voltage substations due to environmental conditions and pollution on insulators.

    Science.gov (United States)

    Castillo Sierra, Rafael; Oviedo-Trespalacios, Oscar; Candelo, John E; Soto, Jose D

    2015-07-01

    Pollution on electrical insulators is one of the greatest causes of failure of substations subjected to high levels of salinity and environmental pollution. Considering leakage current as the main indicator of pollution on insulators, this paper focuses on establishing the effect of the environmental conditions on the risk of failure due to pollution on insulators and determining the significant change in the magnitude of the pollution on the insulators during dry and humid periods. Hierarchical segmentation analysis was used to establish the effect of environmental conditions on the risk of failure due to pollution on insulators. The Kruskal-Wallis test was utilized to determine the significant changes in the magnitude of the pollution due to climate periods. An important result was the discovery that leakage current was more common on insulators during dry periods than humid ones. There was also a higher risk of failure due to pollution during dry periods. During the humid period, various temperatures and wind directions produced a small change in the risk of failure. As a technical result, operators of electrical substations can now identify the cause of an increase in risk of failure due to pollution in the area. The research provides a contribution towards the behaviour of the leakage current under conditions similar to those of the Colombian Caribbean coast and how they affect the risk of failure of the substation due to pollution.

  13. The physical phenomena associated with stator winding insulation condition as detected by the ramped direct high-voltage method

    Science.gov (United States)

    Rux, Lorelynn Mary

    Deregulation of the electric utility industry has increased the need to monitor the state of powerplant equipment, such as critical generators and motors, to improve availability and reduce life cycle costs via condition-based maintenance. To achieve these goals, nondestructive condition assessment and diagnostic tests are necessary to evaluate the quality and condition of a machine's stator winding insulation system. Periodic tests are generally conducted to monitor insulation aging, diagnose problems, or provide some assurance that the winding has a minimum level of electrical strength. The basic principles of insulation testing are presented herein, and the physical mechanisms that affect the current versus voltage response are described. A stator winding insulation model was developed based on this theoretical foundation for use in understanding and analyzing the macroscopic behavior of complex insulation phenomena. A comprehensive, controlled laboratory experiment was conducted on a set of stator coils that were deliberately manufactured with and without insulation defects. Specific defects were chosen to represent the types of insulation problems typically encountered during manufacture or as a result of in-service aging, and included lack of resin cure, loosely-applied insulating tapes, internal conductive contamination, reduced density of the groundwall insulation, and thermal cycling damage. Results are presented from a series of electrical tests conducted on the coil specimens to compare the effectiveness of various test methods in detecting the different insulation problems. The tests included insulation resistance, polarization index, ramped direct voltage, dissipation factor, dielectric spectroscopy, partial discharge, and recovery voltage measurements. Dielectric principles and testing experience obtained during this investigation were applied to a collection of test results obtained by the author from in-service machines during the past ten years

  14. Age-dependent electrical and morphological remodeling of the Drosophila heart caused by hERG/seizure mutations.

    Science.gov (United States)

    Ocorr, Karen; Zambon, Alexander; Nudell, Yoav; Pineda, Santiago; Diop, Soda; Tang, Min; Akasaka, Takeshi; Taylor, Erika

    2017-05-01

    Understanding the cellular-molecular substrates of heart disease is key to the development of cardiac specific therapies and to the prevention of off-target effects by non-cardiac targeted drugs. One of the primary targets for therapeutic intervention has been the human ether a go-go (hERG) K+ channel that, together with the KCNQ channel, controls the rate and efficiency of repolarization in human myocardial cells. Neither of these channels plays a major role in adult mouse heart function; however, we show here that the hERG homolog seizure (sei), along with KCNQ, both contribute significantly to adult heart function as they do in humans. In Drosophila, mutations in or cardiac knockdown of sei channels cause arrhythmias that become progressively more severe with age. Intracellular recordings of semi-intact heart preparations revealed that these perturbations also cause electrical remodeling that is reminiscent of the early afterdepolarizations seen in human myocardial cells defective in these channels. In contrast to KCNQ, however, mutations in sei also cause extensive structural remodeling of the myofibrillar organization, which suggests that hERG channel function has a novel link to sarcomeric and myofibrillar integrity. We conclude that deficiency of ion channels with similar electrical functions in cardiomyocytes can lead to different types or extents of electrical and/or structural remodeling impacting cardiac output.

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

    Directory of Open Access Journals (Sweden)

    Qifeng Lu

    2015-12-01

    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.

  16. Electric Power Transmission Lines

    Data.gov (United States)

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

  17. Natural ageing of EPDM composite insulators

    Energy Technology Data Exchange (ETDEWEB)

    Vlastos, A.E.; Sherif, E. (Chalmers Univ. of Technology, High Voltage Engineering, S-412 96 Gothenburg (SW))

    1990-01-01

    Long-rod composite insulators, with weather sheds (sheds) made of ethylene propylene rubbers (EPDM), were exposed for many years to HVAC and HVDC under realistic conditions and natural pollution. The change of their properties with time and their aging was studied. The results show that the insulator shed material undergoes a slow degradation process and loses successively its water repelling properties which initially make the EPDM composite insulators superior to inorganic glass and porcelain insulator. The outdoor degradation of the shed material depends on the electric stress, in the environmental factors (such as pollution, rain, salt-laden fog, and UV-radiation from sun) and on the materials and fillers used in the construction of the composite insulators. A thorough macro- and microscopic study of the EPDM composite insulator sheds illustrates the differences of the surface state of EPDM insulators of different makes in which different basic material compositions and fillers are used. The poor performance of aged EPDM composite insulators compared to inorganic insulators depends on the design and on environmental factors.

  18. Two-Scale Ion Meandering Caused by the Polarization Electric Field During Asymmetric Reconnection

    Science.gov (United States)

    Wang, Shan; Chen, Li-Jen; Hesse, Michael; Bessho, Naoki; Gershman, Daniel J.; Dorelli, John; Giles, Barbara L.; Torbert, Roy B.; Pollock, Craig J.; Strangeway, Robert; hide

    2016-01-01

    Ion velocity distribution functions (VDFs) from a particle-in-cell simulation of asymmetric reconnection are investigated to reveal a two-scale structure of the ion diffusion region (IDR). Ions bouncing in the inner IDR are trapped mainly by the electric field normal to the current sheet (N direction), while those reaching the outer IDR are turned back mainly by the magnetic force. The resulting inner layer VDFs have counter-streaming populations along N with decreasing counter-streaming speeds away from the midplane while maintaining the out-of-plane speed, and the outer layer VDFs exhibit crescent shapes toward the out-of-plane direction. Observations of the above VDF features and the normal electric fields provide evidence for the two-scale meandering motion.

  19. Local electric stimulation causes conducted calcium response in rat interlobular arteries

    DEFF Research Database (Denmark)

    Salomonsson, Max; Gustafsson, Finn; Andreasen, Ditte

    2002-01-01

    The purpose of the present study was to investigate the conducted Ca(2+) response to local electrical stimulation in isolated rat interlobular arteries. Interlobular arteries were isolated from young Sprague-Dawley rats, loaded with fura 2, and attached to pipettes in a chamber on an inverted...... microscope. Local electrical pulse stimulation (200 ms, 100 V) was administered by means of an NaCl-filled microelectrode (0.7-1 M(Omega)) juxtaposed to one end of the vessel. Intracellular Ca(2+) concentration ([Ca(2+)](i)) was measured with an image system at a site approximately 500 microm from......% of baseline, whereas the response was absent when the electrode was negative. This response was not dependent on perivascular nerves, because the conducted response was unaffected by TTX (1 microM). The conducted [Ca(2+)](i) response was abolished by an ambient Ca(2+) free solution and blunted by nifedipine...

  20. Insulator contamination effects; Efectos de la contaminacion en aislamientos

    Energy Technology Data Exchange (ETDEWEB)

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

    1986-12-31

    Environmental contamination deteriorates the electric insulators, mechanically as well as electrically; the mechanical problems caused by contamination are related basically with materials corrosion and degradation and the electrical problems are related to the deterioration of their dielectric rigidity. From the electrical standpoint, the type of contamination that cause more problems are divided into: marine, desert and industrial. It is not uncommon to find various combinations of these types of contamination. When the electric installations operate in polluted environments, the insulator electric behavior deteriorates, provoking increments in the operation costs for maintenance as well as for replacement. Mexico has large extensions of coasts (marine contamination), where nowadays large cities and productions centers are developed (industrial pollution); also, in some cases for the energy transportation is necessary to go through large land extensions, where no vegetation of any kind exists. For this reason the contamination effect on the electric installations must be considered in order to obtain a reliable and economical energy supply. [Espanol] La contaminacion ambiental deteriora los aisladores electricos tanto mecanica como electricamente; los problemas mecanicos por contaminacion se relacionan en forma basica con la corrosion y degradacion de los materiales, y los electricos se vinculan con el deterioro de su rigidez dielectrica. Desde el punto de vista electrico, los tipos de contaminacion que mas problemas ocasionan se dividen en: marina, desertica e industrial. Es comun encontrar diversas combinaciones de estas. Cuando las instalaciones electricas operan en ambientes contaminados, el comportamiento electrico de los aisladores se deteriora, provocando incrementos en los costos de operacion, tanto por mantenimiento como por reposicion. Mexico cuenta con grandes extensiones de costas (contaminacion marina), donde actualmente se desarrollan ciudades y

  1. Nonlinear Dielectric Response of Water Treed XLPE Cable Insulation

    Energy Technology Data Exchange (ETDEWEB)

    Hvidsten, Sverre

    1999-07-01

    frequency domain dielectric response was larger, and found to be more nonlinear than values measured in time domain. This thesis describes a new mechanism for the nonlinear dielectric response. It is assumed that at low or no applied electric stress the water treed region is characterised by spherical micro voids filled with liquid water separated by channels of crazed insulation. The effect of increasing the test voltage is to cause Maxwell mechanical tensile stresses strong enough to open up the crazing zones and elongate the water droplets into the mechanically weak crazing zones. Finite Element Method (FEM) calculations show that the effect of the re-opening of crazing zones by an increased test voltage, strongly increases the dielectric loss of the water treed insulation. This is qualitatively in good agreement with the experimental results obtained on water treed insulation, where increasing the test voltage above a certain value caused the losses to increase. The typical frequency independent dielectric response of water treed insulation can, however, not be explained by this model. Numerical calculations of losses, indicated that the mechanism of voltage assisted ingress of water is more likely in treed regions with rather low contents of water. The micro-FTIR measurements of single vented water trees indicated that such regions were likely to be present 3-400 (my)m within the tree tip, and close to the insulation screen. The process of refilling water into water tree structures is likely to be associated with a hysteresis effect. When removing (or reducing) the electric field, mechanical relaxation causes the channel to collapse and to slowly recover its former structure. Dielectric response measurements showed that a hysteresis was typically present when the response was nonlinear.

  2. Multiple density layered insulator

    Science.gov (United States)

    Alger, Terry W.

    1994-01-01

    A multiple density layered insulator for use with a laser is disclosed wh provides at least two different insulation materials for a laser discharge tube, where the two insulation materials have different thermoconductivities. The multiple layer insulation materials provide for improved thermoconductivity capability for improved laser operation.

  3. Interface Control Document for the EMPACT Module that Estimates Electric Power Transmission System Response to EMP-Caused Damage

    Energy Technology Data Exchange (ETDEWEB)

    Werley, Kenneth Alan [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Mccown, Andrew William [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)ory

    2016-06-26

    The EPREP code is designed to evaluate the effects of an Electro-Magnetic Pulse (EMP) on the electric power transmission system. The EPREP code embodies an umbrella framework that allows a user to set up analysis conditions and to examine analysis results. The code links to three major physics/engineering modules. The first module describes the EM wave in space and time. The second module evaluates the damage caused by the wave on specific electric power (EP) transmission system components. The third module evaluates the consequence of the damaged network on its (reduced) ability to provide electric power to meet demand. This third module is the focus of the present paper. The EMPACT code serves as the third module. The EMPACT name denotes EMP effects on Alternating Current Transmission systems. The EMPACT algorithms compute electric power transmission network flow solutions under severely damaged network conditions. Initial solutions are often characterized by unacceptible network conditions including line overloads and bad voltages. The EMPACT code contains algorithms to adjust optimally network parameters to eliminate network problems while minimizing outages. System adjustments include automatically adjusting control equipment (generator V control, variable transformers, and variable shunts), as well as non-automatic control of generator power settings and minimal load shedding. The goal is to evaluate the minimal loss of customer load under equilibrium (steady-state) conditions during peak demand.

  4. Magnetic-proximity-induced magnetoresistance on topological insulators

    Science.gov (United States)

    Chiba, Takahiro; Takahashi, Saburo; Bauer, Gerrit E. W.

    2017-03-01

    We theoretically study the magnetoresistance (MR) of two-dimensional massless Dirac electrons as found on the surface of three-dimensional topological insulators (TIs) that are capped by a ferromagnetic insulator (FI). We calculate charge and spin transport by Kubo and Boltzmann theories, taking into account the ladder-vertex correction and the in-scattering due to normal and magnetic disorder. The induced exchange splitting is found to generate an electric conductivity that depends on the magnetization orientation, but its form is very different from both the anisotropic and the spin Hall MR. The in-plane MR vanishes identically for nonmagnetic disorder, while out-of-plane magnetizations cause a large MR ratio. On the other hand, we do find an in-plane MR and planar Hall effect in the presence of magnetic disorder aligned with the FI magnetization. Our results may help us understand recent transport measurements on TI |FI systems.

  5. Nonlinear conduction phenomena in the Mott insulator Ca2RuO4

    Science.gov (United States)

    Okazaki, Ryuji; Nishina, Yasuo; Yasui, Yukio; Terasaki, Ichiro; Nakamura, Fumihiko; Kimura, Yusaku; Sakaki, Mariko; Suzuki, Takashi

    2012-02-01

    The 4d-electron Mott insulator Ca2RuO4 has attracted considerable attention because of its rich electronic states dramatically varied by temperature change, pressure, and isovalent Sr substitution. Recently, Nakamura et al. reported an intriguing result of current-voltage characteristics in Ca2RuO4 and found an E-induced insulator-to-metal transition caused by relatively low electric field E ˜ 50 V/cm [1]. In this study we investigate the nonlinear conduction phenomena in the Mott insulating phase of Ca2RuO4 with a proper evaluation for self-heating effects. By utilizing a non-contact infrared thermometer, sample temperature was accurately determined even in the presence of large Joule heating. The resistivity shows a typical insulating behavior featured by thermal activation with an energy gap, but clearly depends on the applied currents. The result is highlighted by a strong suppression of the energy gap by the electrical currents. A striking similarity to the current dependence of charge-order gap in organic insulators is discussed in terms of the nonequilibrium phase transition. [4pt] [1] F. Nakamura et al., (submitted).

  6. Characterizations of realized metal-insulator-silicon-insulator-metal waveguides and nanochannel fabrication via insulator removal.

    Science.gov (United States)

    Kwon, Min-Suk; Shin, Jin-Soo; Shin, Sang-Yung; Lee, Wan-Gyu

    2012-09-24

    We investigate experimentally metal-insulator-silicon-insulator-metal (MISIM) waveguides that are fabricated by using fully standard CMOS technology. They are hybrid plasmonic waveguides, and they have a feature that their insulator is replaceable with functional material. We explain a fabrication process for them and discuss fabrication results based on 8-inch silicon-on-insulator wafers. We measured the propagation characteristics of the MISIM waveguides that were actually fabricated to be connected to Si photonic waveguides through symmetric and asymmetric couplers. When incident light from an optical source has transverse electric (TE) polarization and its wavelength is 1318 or 1554 nm, their propagation losses are between 0.2 and 0.3 dB/μm. Excess losses due to the symmetric couplers are around 0.5 dB, which are smaller than those due to the asymmetric couplers. Additional measurement results indicate that the MISIM waveguide supports a TE-polarized hybrid plasmonic mode. Finally, we explain a process of removing the insulator without affecting the remaining MISIM structure to fabricate ~30-nm-wide nanochannels which may be filled with functional material.

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

    Directory of Open Access Journals (Sweden)

    Ruijin Liao

    2013-01-01

    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.

  8. Adsorption and surface properties of silica with transformer insulating oils

    Energy Technology Data Exchange (ETDEWEB)

    Jada, A.; Chaou, A.A.; Bertrand, Y.; Moreau, O. [Institute de Chimie des Surfaces et Interfaces, Mulhouse (France)

    2002-06-01

    The presence of polar species in transformer insulating oil may cause degradation and electric discharges in the power transformer. Such oil polar fraction can originate either from the neat oil and/or from its oxidative degradation in the power transformer. The aim of this study is to examine the relation between the insulating oil and the electrical properties of its polar fraction in order to predict eventual failure in the power transformer. We investigate the ambient temperature the adsorption of the polar fractions of various transformers insulating oils (a new and two used oils) from the neat oils onto silica particles. The adsorbed amount was higher for the used oils as compared to the new one. Infrared spectra of the polar fraction indicate the presence of hydroxyl, aromatic and carboxyl functional groups that are found in the asphaltenes compounds. Microelectrophoresis study of the oil polar fraction covered silica particles gives negatively charged oil polar fraction. Such oil surface char depends on the pH and results from the ionisation of the oil acidic surface groups. Finally, we obtain a good correlation between the amount of the oil polar fraction and the magnitude of the zeta potential at the water/oil-silica interface. 38 refs., 3 figs., 1 tab.

  9. 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

    Science.gov (United States)

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

    2017-01-01

    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.

  10. 168kV reduced-size gas insulated switch for Hekinan substation of Chubu Electric Power Co., Inc.; Chubu Denryoku (kabu) Hekinan hendensho 168kV shukushogata gas zetsuen kaihei sochi

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2000-01-10

    Fuji Electric Co., Ltd., has delivered 13 units of 168kV reduced-size gas insulated switches (GIS) to the Hekinan substation of Chubu Electric Power Co., Inc. Their rated currents are 2000/3000/4000A, and they can withstand a short-time amperage of 40kA. The GIS introduced here is based on the excellent result achieved by the 168kV-rate GIS of the SDF type of Fuji Electric Co., Ltd., with its constituent devices reduced in size and composited, and its unit layout optimized. The new GIS occupies approximately 70% of what the conventional type requires for installation, and it weighs approximately 90% of the conventional type in mass. The new product may be separated into two parts, or integrated with the control panel, and the design is expected to shorten the on-site work time and the term of works. As for the number of parts, it is also reduced to approximately 80%, and this enhances GIS reliability. The 13 units were installed in September 1999, adjustment is now complete, and they are to come into service in May 2000. (translated by NEDO)

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

    CERN Document Server

    Read, D E

    2001-01-01

    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...

  12. Monitoring headloss caused by debris on hydro-electric power intake trashracks

    Energy Technology Data Exchange (ETDEWEB)

    Abdelnour, R.; Gong, Y.; Comfort, G. [Fleet Technology Ltd., Kanata, ON (Canada)

    1996-06-01

    The importance of power generation losses at hydro-electric power dams from debris (mostly logs) and ice accumulation was discussed. A system which could monitor headlosses due to debris accumulation at water intake trashracks, was described. Two systems were used at the Chelsea power plant in Quebec. The systems consisted of measuring the water levels of the reservoir and the tailrace. The amount of power generated and the turbine rating curves were used to determine the headlosses. The headlosses due to trash were calculated in real time. Results demonstrated the reliability of the system and showed that it could be implemented at most low head dams in Canada at a reasonable cost. 4 refs., 7 tabs., 6 figs.

  13. Insulation coordination for delta connected transformers

    Energy Technology Data Exchange (ETDEWEB)

    Keri, A.J.F.; Musa, Y.I.; Halladay, J.A. (American Electric Power Service Corp., Columbus, OH (United States))

    1994-04-01

    It is common practice to install only phase to ground surge arresters for transformer insulation protection against electrical stresses. However, this may not adequately protect the delta connected transformer phase to phase winding insulation. High phase to phase overvoltages at the transformer terminals, due to capacitor switching, have been reported. This paper describes the excessive phase to phase overvoltages that can also occur due to wave propagation and surge transfer through transformers. This paper points out the need for surge arrester arrangements that protect both, phase to phase and phase to ground transformer insulations. Surge arrester arrangements, selection criteria, installation practices, and application considerations are discussed in this paper.

  14. Institutional challenges caused by the integration of renewable energy sources in the European electricity sector

    NARCIS (Netherlands)

    Verzijlbergh, R.A.; de Vries, L.J.; Dijkema, G.P.J.; Herder, P.M.

    2016-01-01

    The integration of large amounts of variable renewable energy poses fundamental challenges to the operation and governance of the energy system. In this article we address the main institutional challenges that are caused by the integration of variable renewable energy sources like solar and wind

  15. The impact of large structural brain changes in chronic stroke patients on the electric field caused by transcranial brain stimulation

    DEFF Research Database (Denmark)

    Minjoli, Sena; Saturnino, Guilherme B.; Blicher, Jakob Udby

    2017-01-01

    Transcranial magnetic stimulation (TMS) and transcranial direct current stimulation (TDCS) are two types of non-invasive transcranial brain stimulation (TBS). They are useful tools for stroke research and may be potential adjunct therapies for functional recovery. However, stroke often causes large...... aimed to characterize the impact of these changes on the spatial distribution of the electric field generated by both TBS methods. In addition to confirming the safety of TBS in the presence of large stroke-related structural changes, our aim was to clarify whether targeted stimulation is still possible...

  16. Insulated Foamy Viral Vectors

    Science.gov (United States)

    Browning, Diana L.; Collins, Casey P.; Hocum, Jonah D.; Leap, David J.; Rae, Dustin T.; Trobridge, Grant D.

    2016-01-01

    Retroviral vector-mediated gene therapy is promising, but genotoxicity has limited its use in the clinic. Genotoxicity is highly dependent on the retroviral vector used, and foamy viral (FV) vectors appear relatively safe. However, internal promoters may still potentially activate nearby genes. We developed insulated FV vectors, using four previously described insulators: a version of the well-studied chicken hypersensitivity site 4 insulator (650cHS4), two synthetic CCCTC-binding factor (CTCF)-based insulators, and an insulator based on the CCAAT box-binding transcription factor/nuclear factor I (7xCTF/NF1). We directly compared these insulators for enhancer-blocking activity, effect on FV vector titer, and fidelity of transfer to both proviral long terminal repeats. The synthetic CTCF-based insulators had the strongest insulating activity, but reduced titers significantly. The 7xCTF/NF1 insulator did not reduce titers but had weak insulating activity. The 650cHS4-insulated FV vector was identified as the overall most promising vector. Uninsulated and 650cHS4-insulated FV vectors were both significantly less genotoxic than gammaretroviral vectors. Integration sites were evaluated in cord blood CD34+ cells and the 650cHS4-insulated FV vector had fewer hotspots compared with an uninsulated FV vector. These data suggest that insulated FV vectors are promising for hematopoietic stem cell gene therapy. PMID:26715244

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

    Science.gov (United States)

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

    2015-10-01

    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.

  18. An electric field induced in the retina and brain at threshold magnetic flux density causing magnetophosphenes

    Energy Technology Data Exchange (ETDEWEB)

    Hirata, Akimasa; Takano, Yukinori; Fujiwara, Osamu [Nagoya Institute of Technology, Department of Computer Science and Engineering (Japan); Dovan, Thanh [SP AusNet, Division of Network Strategy and Development (Australia); Kavet, Robert, E-mail: ahirata@nitech.ac.jp [Electric Power Research Institute, Palo Alto, CA (United States)

    2011-07-07

    For magnetic field exposures at extremely low frequencies, the electrostimulatory response with the lowest threshold is the magnetophosphene, a response that corresponds to an adult exposed to a 20 Hz magnetic field of nominally 8.14 mT. In the IEEE standard C95.6 (2002), the corresponding in situ field in the retinal locus of an adult-sized ellipsoidal was calculated to be 53 mV m{sup -1}. However, the associated dose in the retina and brain at a high level of resolution in anatomically correct human models is incompletely characterized. Furthermore, the dose maxima in tissue computed with voxel human models are prone to staircasing errors, particularly for the low-frequency dosimetry. In the analyses presented in this paper, analytical and quasi-static finite-difference time-domain (FDTD) solutions were first compared for a three-layer sphere exposed to a uniform 50 Hz magnetic field. Staircasing errors in the FDTD results were observed at the tissue interface, and were greatest at the skin-air boundary. The 99th percentile value was within 3% of the analytic maximum, depending on model resolution, and thus may be considered a close approximation of the analytic maximum. For the adult anatomical model, TARO, exposed to a uniform magnetic field, the differences in the 99th percentile value of in situ electric fields for 2 mm and 1 mm voxel models were at most several per cent. For various human models exposed at the magnetophosphene threshold at three orthogonal field orientations, the in situ electric field in the brain was between 10% and 70% greater than the analytical IEEE threshold of 53 mV m{sup -1}, and in the retina was lower by roughly 50% for two horizontal orientations (anterior-posterior and lateral), and greater by about 15% for a vertically oriented field. Considering a reduction factor or safety factors of several folds applied to electrostimulatory thresholds, the 99th percentile dose to a tissue calculated with voxel human models may be used as an

  19. Possible fire hazard caused by mismatching electrical chargers with the incorrect device within the operating room.

    LENUS (Irish Health Repository)

    Hargrove, Martin

    2012-02-03

    It has come to our attention that numerous devices that need charging adaptors during cardiopulmonary bypass (CPB) have similar charging sockets but different voltage requirements. This has caused one of our devices in the operating theater to overheat and completely shut down when connected to an incorrect higher-voltage charger. The possibility of fire, device destruction, or patient harm in such circumstances is of serious concern.

  20. Temperature dependent electrical characterisation of Pt/HfO2/n-GaN metal-insulator-semiconductor (MIS Schottky diodes

    Directory of Open Access Journals (Sweden)

    Arjun Shetty

    2015-09-01

    Full Text Available This paper reports an improvement in Pt/n-GaN metal-semiconductor (MS Schottky diode characteristics by the introduction of a layer of HfO2 (5 nm between the metal and semiconductor interface. The resulting Pt/HfO2/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/HfO2/n-GaN Schottky diodes were fabricated. To gain further understanding of the Pt/HfO2/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.

  1. A Study of Insulation Design of a Gas Transformer Using Extra Turns

    Energy Technology Data Exchange (ETDEWEB)

    Heo, Woo Heng; Ha, Yong Sik [Hyosung Industries Co., Ltd (Korea); Hong, Jung Pyo; Kim, Gyu Tak [Changwon University, Changwon (Korea)

    2001-03-01

    This paper deals with the electrical insulation design of a gas insulated power transformer based on extra turns method satisfying the impulse test performed in the worst condition. The calculation of electrical strength in insulation structure was done by 2D finite element method. The gas insulated power transformer was manufactured by selecting the optimum arrangement among design results. the validity of the design result is verified by the impulse test of manufactured machine. (author). 11 refs., 11 figs., 2 tabs.

  2. The impact of large structural brain changes in chronic stroke patients on the electric field caused by transcranial brain stimulation

    Directory of Open Access Journals (Sweden)

    Sena Minjoli

    2017-01-01

    Full Text Available Transcranial magnetic stimulation (TMS and transcranial direct current stimulation (TDCS are two types of non-invasive transcranial brain stimulation (TBS. They are useful tools for stroke research and may be potential adjunct therapies for functional recovery. However, stroke often causes large cerebral lesions, which are commonly accompanied by a secondary enlargement of the ventricles and atrophy. These structural alterations substantially change the conductivity distribution inside the head, which may have potentially important consequences for both brain stimulation methods. We therefore aimed to characterize the impact of these changes on the spatial distribution of the electric field generated by both TBS methods. In addition to confirming the safety of TBS in the presence of large stroke-related structural changes, our aim was to clarify whether targeted stimulation is still possible. Realistic head models containing large cortical and subcortical stroke lesions in the right parietal cortex were created using MR images of two patients. For TMS, the electric field of a double coil was simulated using the finite-element method. Systematic variations of the coil position relative to the lesion were tested. For TDCS, the finite-element method was used to simulate a standard approach with two electrode pads, and the position of one electrode was systematically varied. For both TMS and TDCS, the lesion caused electric field “hot spots” in the cortex. However, these maxima were not substantially stronger than those seen in a healthy control. The electric field pattern induced by TMS was not substantially changed by the lesions. However, the average field strength generated by TDCS was substantially decreased. This effect occurred for both head models and even when both electrodes were distant to the lesion, caused by increased current shunting through the lesion and enlarged ventricles. Judging from the similar peak field strengths compared

  3. The impact of large structural brain changes in chronic stroke patients on the electric field caused by transcranial brain stimulation.

    Science.gov (United States)

    Minjoli, Sena; Saturnino, Guilherme B; Blicher, Jakob Udby; Stagg, Charlotte J; Siebner, Hartwig R; Antunes, André; Thielscher, Axel

    2017-01-01

    Transcranial magnetic stimulation (TMS) and transcranial direct current stimulation (TDCS) are two types of non-invasive transcranial brain stimulation (TBS). They are useful tools for stroke research and may be potential adjunct therapies for functional recovery. However, stroke often causes large cerebral lesions, which are commonly accompanied by a secondary enlargement of the ventricles and atrophy. These structural alterations substantially change the conductivity distribution inside the head, which may have potentially important consequences for both brain stimulation methods. We therefore aimed to characterize the impact of these changes on the spatial distribution of the electric field generated by both TBS methods. In addition to confirming the safety of TBS in the presence of large stroke-related structural changes, our aim was to clarify whether targeted stimulation is still possible. Realistic head models containing large cortical and subcortical stroke lesions in the right parietal cortex were created using MR images of two patients. For TMS, the electric field of a double coil was simulated using the finite-element method. Systematic variations of the coil position relative to the lesion were tested. For TDCS, the finite-element method was used to simulate a standard approach with two electrode pads, and the position of one electrode was systematically varied. For both TMS and TDCS, the lesion caused electric field "hot spots" in the cortex. However, these maxima were not substantially stronger than those seen in a healthy control. The electric field pattern induced by TMS was not substantially changed by the lesions. However, the average field strength generated by TDCS was substantially decreased. This effect occurred for both head models and even when both electrodes were distant to the lesion, caused by increased current shunting through the lesion and enlarged ventricles. Judging from the similar peak field strengths compared to the healthy

  4. Thermal shock resistance ceramic insulator

    Science.gov (United States)

    Morgan, Chester S.; Johnson, William R.

    1980-01-01

    Thermal shock resistant cermet insulators containing 0.1-20 volume % metal present as a dispersed phase. The insulators are prepared by a process comprising the steps of (a) providing a first solid phase mixture of a ceramic powder and a metal precursor; (b) heating the first solid phase mixture above the minimum decomposition temperature of the metal precursor for no longer than 30 minutes and to a temperature sufficiently above the decomposition temperature to cause the selective decomposition of the metal precursor to the metal to provide a second solid phase mixture comprising particles of ceramic having discrete metal particles adhering to their surfaces, said metal particles having a mean diameter no more than 1/2 the mean diameter of the ceramic particles, and (c) densifying the second solid phase mixture to provide a cermet insulator having 0.1-20 volume % metal present as a dispersed phase.

  5. Band structure engineering in topological insulator based heterostructures.

    Science.gov (United States)

    Menshchikova, T V; Otrokov, M M; Tsirkin, S S; Samorokov, D A; Bebneva, V V; Ernst, A; Kuznetsov, V M; Chulkov, E V

    2013-01-01

    The ability to engineer an electronic band structure of topological insulators would allow the production of topological materials with tailor-made properties. Using ab initio calculations, we show a promising way to control the conducting surface state in topological insulator based heterostructures representing an insulator ultrathin films on the topological insulator substrates. Because of a specific relation between work functions and band gaps of the topological insulator substrate and the insulator ultrathin film overlayer, a sizable shift of the Dirac point occurs resulting in a significant increase in the number of the topological surface state charge carriers as compared to that of the substrate itself. Such an effect can also be realized by applying the external electric field that allows a gradual tuning of the topological surface state. A simultaneous use of both approaches makes it possible to obtain a topological insulator based heterostructure with a highly tunable topological surface state.

  6. Dielectric insulation and high-voltage issues

    CERN Document Server

    Tommasini, D

    2010-01-01

    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.

  7. 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

    Energy Technology Data Exchange (ETDEWEB)

    Palacios Lopez, Arturo

    2002-07-01

    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.

  8. Study of Composite Insulator Sheds Subjected to Wheel Test

    OpenAIRE

    Mackiewicz M.; Mikulski J.L.; Wańkowicz J.; Kucharski S.; Ranachowski P.; Ranachowski Z.

    2017-01-01

    The paper presents investigation of the properties of the surface and the material stiffness – flexibility of series of samples taken from the sheds of the composite insulators. The insulators were previously subjected to wheel test. The wheel test and 1000 h salt fog test are regarded as alternative examination of the material resistance to the effects of electrical surface discharges. There were investigated two series of the samples of the composite insulators sheds. Examined specimens, ma...

  9. Explosion resistant insulator and method of making same

    Science.gov (United States)

    Meyer, Jeffry R.; Billings, Jr., John S.; Spindle, Harvey E.; Hofmann, Charles F.

    1983-01-01

    An electrical insulator assembly and method of manufacturing same, having a generally cylindrical or conical body portion formed of a breakable cast solid insulation system and a reinforcing member having a corrugated configuration and formed of a web or mesh type reinforcing fabric. When the breakable body member has been broken, the corrugated configured reinforcing web member provides a path of escape for pressurized insulating fluid while limiting the movement of body member fragments in the direction of escape of the pressurized fluid.

  10. From a normal insulator to a topological insulator in plumbene

    Science.gov (United States)

    Yu, Xiang-Long; Huang, Li; Wu, Jiansheng

    2017-03-01

    Plumbene, similar to silicene, has a buckled honeycomb structure with a large band gap (˜400 meV). All previous studies have shown that it is a normal insulator. Here, we perform first-principles calculations and employ a sixteen-band tight-binding model with nearest-neighbor and next-nearest-neighbor hopping terms to investigate electronic structures and topological properties of the plumbene monolayer. We find that it can become a topological insulator with a large bulk gap (˜200 meV) through electron doping, and the nontrivial state is very robust with respect to external strain. Plumbene can be an ideal candidate for realizing the quantum spin Hall effect at room temperature. By investigating effects of external electric and magnetic fields on electronic structures and transport properties of plumbene, we present two rich phase diagrams with and without electron doping and propose a theoretical design for a four-state spin-valley filter.

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

    KAUST Repository

    Hu, Longhua

    2016-10-02

    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

  12. Dielectric-wall linear accelerator with a high voltage fast rise time switch that includes a pair of electrodes between which are laminated alternating layers of isolated conductors and insulators

    Science.gov (United States)

    Caporaso, George J.; Sampayan, Stephen E.; Kirbie, Hugh C.

    1998-01-01

    A dielectric-wall linear accelerator is improved by a high-voltage, fast rise-time switch that includes a pair of electrodes between which are laminated alternating layers of isolated conductors and insulators. A high voltage is placed between the electrodes sufficient to stress the voltage breakdown of the insulator on command. A light trigger, such as a laser, is focused along at least one line along the edge surface of the laminated alternating layers of isolated conductors and insulators extending between the electrodes. The laser is energized to initiate a surface breakdown by a fluence of photons, thus causing the electrical switch to close very promptly. Such insulators and lasers are incorporated in a dielectric wall linear accelerator with Blumlein modules, and phasing is controlled by adjusting the length of fiber optic cables that carry the laser light to the insulator surface.

  13. Electrical engineer's reference book

    CERN Document Server

    Laughton, M A

    1985-01-01

    Electrical Engineer's Reference Book, Fourteenth Edition focuses on electrical engineering. The book first discusses units, mathematics, and physical quantities, including the international unit system, physical properties, and electricity. The text also looks at network and control systems analysis. The book examines materials used in electrical engineering. Topics include conducting materials, superconductors, silicon, insulating materials, electrical steels, and soft irons and relay steels. The text underscores electrical metrology and instrumentation, steam-generating plants, turbines

  14. THE TECHNOLOGICAL AND EXPLOITATIVE FACTORS OF LOCAL INCREASE OF ELECTRIC FIELD STRENGTH IN THE POWER CABLE OF COAXIAL DESIGN

    Directory of Open Access Journals (Sweden)

    G. V. Bezprozvannych

    2016-12-01

    different effects on the distribution of the electrical field strength at the conductor and the insulation. The electrical field strength is increased by 50 % in the core and 17 % - on the surface of the insulation at 10 % eccentricity between conductor and insulation. Availability elliptic insulation leads to a redistribution of the electric field: field strength at the surface of the insulation is 2 times higher electric field strength on the surface of the conductor. Water treeing spherical shape filled with water with a dielectric constant of 6.9, lead to a local increase of electric field intensity is 5 - 10 times. Originality. Simulation results show that the presence of water treeing concentrated with individual heterogeneity characteristic impedance causes a change in shape and duration of the probe signal rectangular. Practical value. Time domain reflectometer can be considered as one of the promising methods for diagnosing operational irregularities (ellipticity, eccentricity, water treeing in power cables.

  15. Effect of the stresses caused by substrate on the electrical conductivity of ferromagnetic manganite lanthanum-barium films

    Science.gov (United States)

    Ovsyannikov, G. A.; Shaikhulov, T. A.; Shakhunov, V. A.; Demidov, V. V.; Andreev, N. V.; Pestun, A. E.; Preobrazhenskii, V. L.

    2017-11-01

    This is a complex study of the electrophysical and magnetic characteristics of epitaxial manganite La0.7Ba0.3MnO3 (LBMO) films under conditions of crystal structure stresses caused by misfit in the lattice parameters of the LBMO crystal and a substrate. The substrate used had the lattice parameter smaller than that in the LBMO crystal. It is shown that the temperature dependence of the electrical resistance of the films at low temperatures is not dependent on the existence of stresses in the film and agrees well with the calculation with allowance made for the interaction of carriers with magnetic excitations in the presence of strongly correlated electronic states. The study of the ferromagnetic resonance line indicates an inhomogeneity of the ferromagnetic phase in the LBMO films and the increase in the ferromagnetic resonance line width with decreasing temperature.

  16. Hybrid and electric low-noise cars cause an increase in traffic accidents involving vulnerable road users in urban areas.

    Science.gov (United States)

    Brand, Stephan; Petri, Maximilian; Haas, Philipp; Krettek, Christian; Haasper, Carl

    2013-01-01

    Due to resource scarcity, the number of low-noise and electric cars is expected to increase rapidly. The frequent use of these cars will lead to a significant reduction of traffic related noise and pollution. On the other hand, due to the adaption and conditioning of vulnerable road users the number of traffic accidents involving pedestrians and bicyclists is postulated to increase as well. Children, older people with reduced eyesight and the blind are especially reliant on a combination of acoustic and visual warning signals with approaching or accelerating vehicles. This is even more evident in urban areas where the engine sound is the dominating sound up to 30 kph (kilometres per hour). Above this, tyre-road interaction is the main cause of traffic noise. With the missing typical engine sound a new sound design is necessary to prevent traffic accidents in urban areas. Drivers should not be able to switch the sound generator off.

  17. 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

    Directory of Open Access Journals (Sweden)

    F. J. P. Sousa

    2004-09-01

    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

  18. 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

    CERN Document Server

    International Electrotechnical Commission. Geneva

    2004-01-01

    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.

  19. Influence of Fine Metal Particles on Surface Discharge Characteristics of Outdoor Insulators

    Directory of Open Access Journals (Sweden)

    Yong Liu

    2016-01-01

    Full Text Available Focusing on the influence of fine metal particles on the insulation characteristics of outdoor insulators, spherical micrometer-level iron powders were used to represent fine metal particles of different parameters on a polymer insulator specimen surface. Dynamic movement and lift-off behavior of fine particles, as well as the triggered surface discharges under AC voltage were investigated in a uniform electric field under different experimental conditions. The results reveal that the inception, propagation and intensity of surface discharges are significantly affected by the particle parameters, including particle size, amount and distributing characteristic. Based on the measurement of light emission during the flashover process using a high-speed camera, the process of surface discharge to flashover triggered by the fine metal particles were investigated to obtain a relationship between flashover voltage, discharge light intensity and particle parameters. It is suggested that particle size smaller than 28 µm and particle amount more than 40 mg in contact with the non-uniform distribution can cause a significant distortion and intensification of the electric field resulting in a higher risk of surface discharges leading to flashover. Such investigations can enhance the operating reliability of outdoor insulators subjected to these conditions.

  20. Stability Study of Flexible 6,13-Bis(triisopropylsilylethynylpentacene Thin-Film Transistors with a Cross-Linked Poly(4-vinylphenol/Yttrium Oxide Nanocomposite Gate Insulator

    Directory of Open Access Journals (Sweden)

    Jin-Hyuk Kwon

    2016-03-01

    Full Text Available We investigated the electrical and mechanical stability of flexible 6,13-bis(triisopropylsilylehtynylpentacene (TIPS-pentacene thin-film transistors (TFTs that were fabricated on polyimide (PI substrates using cross-linked poly(4-vinylphenol (c-PVP and c-PVP/yttrium oxide (Y2O3 nanocomposite films as gate insulators. Compared with the electrical characteristics of TIPS-pentacene TFTs with c-PVP insulators, the TFTs with c-PVP/Y2O3 nanocomposite insulators exhibited enhancements in the drain current and the threshold voltage due to an increase in the dielectric capacitance. In electrical stability experiments, a gradual decrease in the drain current and a negative shift in the threshold voltage occurred during prolonged bias stress tests, but these characteristic variations were comparable for both types of TFT. On the other hand, the results of mechanical bending tests showed that the characteristic degradation of the TIPS-pentacene TFTs with c-PVP/Y2O3 nanocomposite insulators was more critical than that of the TFTs with c-PVP insulators. In this study, the detrimental effect of the nanocomposite insulator on the mechanical stability of flexible TIPS-pentacene TFTs was found to be caused by physical adhesion of TIPS-pentacene molecules onto the rough surfaces of the c-PVP/Y2O3 nanocomposite insulator. These results indicate that the dielectric and morphological properties of polymeric nanocomposite insulators are significant when considering practical applications of flexible electronics operated at low voltages.

  1. Structure Change of the Insulating Composite

    Directory of Open Access Journals (Sweden)

    Vaclav Mentlik

    2008-01-01

    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.

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

    Science.gov (United States)

    Rajagopal Reddy, V.

    2016-05-01

    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.

  3. Antireduction Insulator For Solid-Electrolyte Cell

    Science.gov (United States)

    Shlichta, Paul J.

    1990-01-01

    Depletion of oxygen from electrolyte prevented. Proposed to add layer of electrical insulation between solid electrolyte and portion of porous negative electrode under negative metal contact in solid-electrolyte cell. Helps maintain efficiency of cell by preventing "shadow" effect degrading portion of electrolyte under negative contact and sometimes near seals.

  4. 7 CFR 1755.890 - RUS specification for filled telephone cables with expanded insulation.

    Science.gov (United States)

    2010-01-01

    ... direct current potential between the conductors, using a light or buzzer to indicate electrical contact... conductors are solid copper, individually insulated with an extruded cellular insulating compound which may be either totally expanded or expanded with a solid skin coating. (ii) The insulated conductors are...

  5. PROBLEMS FOR DEVELOPMENT OF TECHNIQUE AND TECHNOLOGY OF COMPOSITE INSULATORS IN WESTERN EUROPE

    Directory of Open Access Journals (Sweden)

    L. Suboch

    2005-01-01

    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.

  6. EXPERIMENTAL STUDY FOR PERFORMANCE EVALUATION OF INSULATOR USING VARIOUS COATING MATERIALS UNDER DIFFERENT ATMOSPHERIC CONDITIONS

    OpenAIRE

    Akshay Singh Thakur; Prof. Arun Pachori

    2017-01-01

    In this study, we have an insulator is subjected to high voltage under various atmospheric condition. Without porcelain and asbestos coatings to judge the performance and with porcelain and asbestos coatings to judge the performance of electrical insulation materials, upto 44 KV during various atmospheric condition. And for porcelain insulating material, upto 41 KV.

  7. Certain applied electrical signals during EPG cause negative effects on stylet probing behaviors by adult Lygus lineolaris (Hemiptera: Miridae)

    Science.gov (United States)

    This study is the first to fully evaluate whether electrical signals applied to insects during electropenetrography (EPG; also called electrical penetration graph) affect insect behavior. During EPG, electrical signals are applied to plants, and thus to the gold-wire-tethered insects feeding on elec...

  8. Electric field analysis

    CERN Document Server

    Chakravorti, Sivaji

    2015-01-01

    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.

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

    CERN Document Server

    Granieri, P P

    2013-01-01

    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...

  10. ESTIMATION OF INSULATOR CONTAMINATIONS BY MEANS OF REMOTE SENSING TECHNIQUE

    Directory of Open Access Journals (Sweden)

    G. Han

    2016-06-01

    Full Text Available The accurate estimation of deposits adhering on insulators is critical to prevent pollution flashovers which cause huge costs worldwide. The traditional evaluation method of insulator contaminations (IC is based sparse manual in-situ measurements, resulting in insufficient spatial representativeness and poor timeliness. Filling that gap, we proposed a novel evaluation framework of IC based on remote sensing and data mining. Varieties of products derived from satellite data, such as aerosol optical depth (AOD, digital elevation model (DEM, land use and land cover and normalized difference vegetation index were obtained to estimate the severity of IC along with the necessary field investigation inventory (pollution sources, ambient atmosphere and meteorological data. Rough set theory was utilized to minimize input sets under the prerequisite that the resultant set is equivalent to the full sets in terms of the decision ability to distinguish severity levels of IC. We found that AOD, the strength of pollution source and the precipitation are the top 3 decisive factors to estimate insulator contaminations. On that basis, different classification algorithm such as mahalanobis minimum distance, support vector machine (SVM and maximum likelihood method were utilized to estimate severity levels of IC. 10-fold cross-validation was carried out to evaluate the performances of different methods. SVM yielded the best overall accuracy among three algorithms. An overall accuracy of more than 70% was witnessed, suggesting a promising application of remote sensing in power maintenance. To our knowledge, this is the first trial to introduce remote sensing and relevant data analysis technique into the estimation of electrical insulator contaminations.

  11. Plasmonics in Topological Insulators

    Directory of Open Access Journals (Sweden)

    Yi-Ping Lai

    2014-04-01

    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.

  12. Surface growth of MG(multilayer graphene)-SiC nanofillers/poly(vinylidene fluoride) composites for improving thermal conductivity and maintaining electrical insulation

    Science.gov (United States)

    He, Jing; Guo, Yulan; Tian, Konghu; Wang, Hua; Su, Zheng; Huang, Weiqi; Tian, Xingyou

    2017-08-01

    In the present research, a high-frequency heating process with the advantages of simplicity and high yield was applied to synthesize multilayer graphene-SiC nanofillers (MG-SiCnf) and found to boost yields dramatically. The growth process of MG-SiCnf was also investigated. Nanofillers grown on an MG surface consisted of both SiC particles and SiC nanofibers. Interestingly, the growth process of SiC nanofibers included two main steps: firstly, SiC particles gathered on the edge of the MG, and then they grew into SiC nanofibers. SiC nanofibers enhanced the thermal conductivity of materials whereas SiC particles tended to hinder electronic transmission. The vertical and in-plane orientated thermal conductivities of poly(vinylidene fluoride) (PVDF)/MG-SiCnf composites were determined to be 0.28 and 30.491 W m-1 K-1, while the maximum value of the electrical conductivity of PVDF/MG-SiCnf composites was only 2.0  ×  10-11 S cm-1. In addition, the storage modulus of PVDF/MG-SiCnf composites also improved remarkably in comparison with that of pure PVDF.

  13. Do clinical examination gloves provide adequate electrical insulation for safe hands-on defibrillation? II: Material integrity following exposure to defibrillation waveforms.

    Science.gov (United States)

    Petley, Graham W; Deakin, Charles D

    2013-07-01

    Maintaining contact with the patient during defibrillator discharge has been proposed as a method for reducing no flow time but carries an associated risk of electrocution of the rescuer. This study describes an investigation to determine if typical clinical examination gloves possess the dielectric strength needed to prevent breakdown at defibrillation voltages; a factor essential to protect the rescuer. Four types of examination glove typically used in a clinical environment were tested with two types of defibrillation waveform commonly used. For each type of glove, 10 samples were tested initially using a monophasic defibrillation waveform and then, using a fresh sample of gloves, with a Biphasic waveform. For each glove the number of shocks required before electrical breakdown occurred was recorded. Kimberly Clark KC300 (nitrile), Kimberly Clark KC500 purple (nitrile), PH Medisavers GN90 (nitrile) and Bodyguards GL6622 (Vinyl) were tested using a monophasic defibrillation waveform and broke down after a median of 1, 4.5, 1 and 1 shocks respectively. The equivalent values for Biphasic defibrillator were 2, >10, 2.5 and 1 shocks. Typical clinical examination gloves do not possess the dielectric strength required to protect a rescuer from defibrillation voltages during hands-on chest compressions. Copyright © 2013 Elsevier Ireland Ltd. All rights reserved.

  14. Particle trap with dielectric barrier for use in gas insulated transmission lines

    Science.gov (United States)

    Dale, S.J.

    1982-06-15

    A gas-insulated transmission line includes an outer sheath, an inner conductor within the outer sheath, insulating supports supporting the inner conductor within the outer sheath, and an insulating gas electrically insulating the inner conductor from the outer sheath. An apertured particle trapping electrode is disposed within the outer sheath, and the electrode has a pair of dielectric members secured at each longitudinal end thereof, with the dielectric members extending outwardly from the apertured electrode. 7 figs.

  15. Design and Construction of a Live Insulator Washing System for Transformers

    OpenAIRE

    Lizama-Cámara Y.A.; Mendieta-Antúnez J.A.; Blanco-Brisset E.; Olivares Galván J.C.; Escarela-Pérez R.

    2012-01-01

    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 ins...

  16. Gas insulated transmission line with insulators having field controlling recesses

    Science.gov (United States)

    Cookson, Alan H.; Pederson, Bjorn O.

    1984-01-01

    A gas insulated transmission line having a novel insulator for supporting an inner conductor concentrically within an outer sheath. The insulator has a recess contiguous with the periphery of one of the outer and inner conductors. The recess is disposed to a depth equal to an optimum gap for the dielectric insulating fluid used for the high voltage insulation or alternately disposed to a large depth so as to reduce the field at the critical conductor/insulator interface.

  17. Silicon on insulator with active buried regions

    Science.gov (United States)

    McCarthy, Anthony M.

    1996-01-01

    A method 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.

  18. Overvoltages and insulation coordination; Ueberspannungen und Isolationskoordination

    Energy Technology Data Exchange (ETDEWEB)

    Feser, K. [Stuttgart Univ. (Germany). Inst. fuer Energieuebertragung und Hochspannungstechnik

    1998-04-03

    Aufgabe der Isolationskoordination ist es, die Festigkeit der Isolationen mit den zu erwartenden Beanspruchungen im Netz in Einklang zu bringen. Dieser Beitrag gibt zunaechst einen Einblick in die Entstehung und Ausbreitung von Ueberspannungen in Uebertragungs- und Verteilnetzen. Anschliessend wird die Festigkeit unterschiedlicher Isolationsklassen charakterisiert und gezeigt, wie die Isolationskoordination anhand von Wahrscheinlichkeitsaussagen ueber Ueberspannungen und Durchbruchspannungen vorgenommen werden kann. (orig.) [Deutsch] It is the function of insulation coordination to adjust the strength of insulation to the expected network loads. This article outlines the causes and spreading of overvoltages in transmission and distribution networks and the proceeds to characterize the strength of different insulation categories and to show how insulation coordination is possible on the basis of predictions of the probability of overvoltages and breakdown voltages. (orig.)

  19. Insulation coordination in distribution liveline maintenance

    Energy Technology Data Exchange (ETDEWEB)

    Gela, G.; Balpinarli, M. (Dept. of Electrical Engineering, The Ohio State Univ., Columbus, OH (US))

    1988-10-01

    Insulation coordination principles are applied in this paper to assess the expected performance of distribution liveline maintenance equipment. Rubber gloves are used as an example. Breakdown probability distributions for Class II, III, and IV gloves are given for AC and slow-front surge voltages. Available (although scarce) data on observed surge magnitudes in sample distribution systems are quoted. Although quantitative evaluation of the risk of failure of liveline maintenance equipment cannot be performed due to insufficient data on surge performance of distribution systems, some qualitative conclusions can be derived. Based on available glove breakdown voltage values (electric strength) and in-service surge magnitudes (electric stress), it is apparent that flexible liveline maintenance equipment should be able to perform without failure. Additional extensive data base on electric stresses (surges) in distribution systems is needed for quantitative insulation coordination studies.

  20. Translucent insulating building envelope

    DEFF Research Database (Denmark)

    Rahbek, Jens Eg

    1997-01-01

    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....

  1. Electrical conductivity and thermal behavior of solid electrolytes based on alkali carbonates and sulfates

    NARCIS (Netherlands)

    Brosda, S.; Bouwmeester, Henricus J.M.; Guth, U.

    1997-01-01

    Both thermal stability and electrical conductivity of alkali ion conducting Na2CO3 and Na2SO4, were improved by adding alkaline earth carbonates and sulfates, respectively, as well as insulating materials like ¿-Al2O3. The admixing of divalent compounds causes two effects. First a more or less

  2. Sound insulation between dwellings

    DEFF Research Database (Denmark)

    Rasmussen, Birgit

    2011-01-01

    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...

  3. Sound Insulation between Dwellings

    DEFF Research Database (Denmark)

    Rasmussen, Birgit

    2011-01-01

    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...

  4. Electrical and carrier transport properties of the Au/Y2O3/n-GaN metal-insulator-semiconductor (MIS) diode with rare-earth oxide interlayer

    Science.gov (United States)

    Venkata Prasad, C.; Rajagopal Reddy, V.; Choi, Chel-Jong

    2017-04-01

    The electrical and transport properties of rare-earth Y2O3 on n-type GaN with Au electrode have been investigated by current-voltage and capacitance-voltage techniques at room temperature. The Au/Y2O3/n-GaN metal-insulator-semiconductor (MIS) diode shows a good rectification behavior compared to the Au/n-GaN metal-semiconductor (MS) diode. Statistical analysis showed that a mean barrier height (BH) and ideality factor are 0.78 eV and 1.93, and 0.96 eV and 2.09 for the Au/n-GaN MS and Au/Y2O3/n-GaN MIS diodes, respectively. Results indicate that the high BH is obtained for the MIS diode compared to the MS diode. The BH, ideality factor and series resistance are also estimated by Cheung's function and Norde method. From the forward current-voltage data, the interface state density ( N SS) is estimated for both the MS and MIS Schottky diodes, and found that the estimated N SS is lower for the MIS diode compared to the MS diode. The results reveal that the introduction of Y2O3 interlayer facilitated the reduction of N SS of the Au/n-GaN interface. Experimental results suggest that the Poole-Frenkel emission is a dominant conduction mechanism in the reverse bias region of both Au/n-GaN MS and Au/Y2O3/n-GaN MIS diodes.

  5. Insulation Condition Assessment of Power Transformers Using Accelerated Ageing Tests

    OpenAIRE

    MIRZAIE, Mohammad; Gholami, Ahmad; TAYEBI, Hamid Reza

    2009-01-01

    Thermal stress due to losses and environment temperature causes degradation to paper/oil insulation systems in transformers, even at operating temperature. Experience indicates that thermal ageing of oil and paper in power transformers leads to the change of some insulation characteristics. In this paper, insulating papers immersed in oil have been acceleratory aged at 140, 150, and 160 °C under laboratory conditions. Some of the oil properties, such as water content, breakdown vo...

  6. Flux pumping for non-insulated and metal-insulated HTS coils

    Science.gov (United States)

    Ma, Jun; Geng, Jianzhao; Coombs, T. A.

    2018-01-01

    High-temperature superconducting (HTS) coils wound from coated conductors without turn-to-turn insulation (non-insulated (NI) coils) have been proven with excellent electrical and thermal performances. However, the slow charging of NI coils has been a long-lasting problem. In this work, we explore using a transformer-rectifier HTS flux pump to charge an NI coil and a metal-insulated coil. The charging performance comparison is made between different coils. Comprehensive study is done to thoroughly understand the electrical-magnetic transience in charging these coils. We will show that the low-voltage high-current flux pump is especially suitable for charging NI coils with very low characteristic resistance.

  7. Topological Field Theory of Time-Reversal Invariant Insulators

    Energy Technology Data Exchange (ETDEWEB)

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

    2010-03-19

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

  8. Development and analysis of insulation constructions for aerospace wiring applications

    Science.gov (United States)

    Slenski, George A.; Woodford, Lynn M.

    1993-03-01

    The Wright Laboratory Materials Directorate at WPAFB, Ohio recently completed a research and development program under contract with the McDonnell Douglas Aerospace Company, St. Louis, Missouri. Program objectives were to develop wire insulation performance requirements, evaluate candidate insulations, and prepare preliminary specification sheets on the most promising candidates. Aircraft wiring continues to be a high maintenance item and a major contributor to electrically-related aircraft mishaps. Mishap data on aircraft show that chafing of insulation is the most common mode of wire failure. Improved wiring constructions are expected to increase aircraft performance and decrease costs by reducing maintenance actions. In the laboratory program, new insulation constructions were identified that had overall improved performance in evaluation tests when compared to currently available MIL-W-81381 and MIL-W-22759 wiring. These insulations are principally aromatic polyimide and crosslinked ethylene tetrafluoroethylene (ETFE), respectively. Candidate insulations identified in preliminary specification sheets were principally fluoropolymers with a polyimide inner layer. Examples of insulation properties evaluated included flammability, high temperature mechanical and electrical performance, fluid immersion, and susceptibility to arc propagation under applied power chafing conditions. Potential next generation wire insulation materials are also reviewed.

  9. An Education in Electrical Safety.

    Science.gov (United States)

    McBride, John W.; Chiappetta, Eugene L.

    1992-01-01

    Discusses teaching electrical safety guidelines in the process of teaching the concepts related to electricity. Discusses household current; electrical insulation; and examples of electrical safety in the home related to appliances, the bathroom, the yard and the neighborhood. (10 references) (MDH)

  10. Optimisation of Multilayer Insulation an Engineering Approach

    CERN Document Server

    Chorowski, M; Parente, C; Riddone, G

    2001-01-01

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

  11. Correlation analysis between ceramic insulator pollution and acoustic emissions

    Directory of Open Access Journals (Sweden)

    Benjamín Álvarez-Nasrallah

    2015-01-01

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

  12. Thermal insulation. Non-utilized energy need not be generated. Four rules for a successful thermal insulation by means of building insulation; Waermedaemmung. Energie, die nicht gebraucht wird, muss man nicht erzeugen. Vier Regeln fuer erfolgreichen Waermeschutz durch Gebaeudedaemmung

    Energy Technology Data Exchange (ETDEWEB)

    Patschke, Markus [3E-Consult, Nordkirchen (Germany); Drewer, Arnold [IpeG-Institut, Paderborn (Germany)

    2011-07-15

    The heat supply of buildings causes nearly one third of the energy consumption of an industrialized country. In 2006, the climate-adjusted heat consumption of private households in Germany amounted nearly 600 billion kWh. This consumption caused more than 167 million tons of CO{sub 2}. Heat insulation measures in buildings are required for all heat-transferring enveloping surface. Under this aspect, the contribution under consideration reports on four fundamental rules for a cost-efficient building insulation: (a) Only heated rooms should be insulated thermally; (b) Location and thermal insulation of cavities; (c) Selection of a suitable insulating material; (d) Consideration of an economic sustainability.

  13. Via sidewall insulation for through cell via contacts

    Science.gov (United States)

    de Lafontaine, Mathieu; Jaouad, Abdelatif; Darnon, Maxime; Volatier, Maïté; Arès, Richard; Fafard, Simon; Aimez, Vincent

    2017-09-01

    Over the past few years, through cell via contacts (TCVC) architecture has been the object of a growing interest to replace standard front side and backside contact on concentrated photovoltaic (CPV) cells. The technology is based on transferring the front side contact to the backside using insulated and metallized vias. This architecture could reduce shading and series resistance, thus increasing device efficiency. However, the processes involved in TCVC fabrication increases the risk of creating short-circuit, reducing significantly the efficiency of the solar cell. Therefore, the electrical insulation must be defect free. In this paper, an insulation validation protocol is proposed in order to thoroughly study the insulation quality. This process has been used to compare two insulation deposition techniques candidates: plasma-enhanced chemical vapor deposition (PECVD) and plasma-enhanced atomic layer deposition (PEALD). Results show that the insulation validation protocol presents several strengths such as revealing defects otherwise unobservable even with scanning electron microscopy. PECVD insulation presents several insulation defects whereas PEALD presents almost no defects making it suited for via insulation.

  14. Electrostatic electrochemistry at insulators.

    Science.gov (United States)

    Liu, Chongyang; Bard, Allen J

    2008-06-01

    The identity of charges generated by contact electrification on dielectrics has remained unknown for centuries and the precise determination of the charge density is also a long-standing challenge. Here, electrostatic charges on Teflon (polytetrafluoroethylene) produced by rubbing with Lucite (polymethylmethacrylate) were directly identified as electrons rather than ions by electrochemical (redox) experiments with charged Teflon used as a single electrode in solution causing various chemical reactions: pH increases; hydrogen formation; metal deposition; Fe(CN)(6)(3-) reduction; and chemiluminescence in the system of Teflon(-)/Ru(bpy)(3)(2+)/S(2)O(8)(2-) (analogous to electrogenerated chemiluminescence). Moreover, copper deposition could be amplified by depositing Pd first in a predetermined pattern, followed by electroless deposition to produce Cu lines. This process could be potentially important for microelectronic and other applications because Teflon has desirable properties including a low dielectric constant and good thermal stability. Charge density was determined using Faraday's law and the significance of electron transfer processes on charged polymers and potentially other insulators have been demonstrated.

  15. Improving Powder Magnetic Core Properties via Application of Thin, Insulating Silica-Nanosheet Layers on Iron Powder Particles

    Directory of Open Access Journals (Sweden)

    Toshitaka Ishizaki

    2016-12-01

    Full Text Available A thin, insulating layer with high electrical resistivity is vital to achieving high performance of powder magnetic cores. Using layer-by-layer deposition of silica nanosheets or colloidal silica over insulating layers composed of strontium phosphate and boron oxide, we succeeded in fabricating insulating layers with high electrical resistivity on iron powder particles, which were subsequently used to prepare toroidal cores. The compact density of these cores decreased after coating with colloidal silica due to the substantial increase in the volume, causing the magnetic flux density to deteriorate. Coating with silica nanosheets, on the other hand, resulted in a higher electrical resistivity and a good balance between high magnetic flux density and low iron loss due to the thinner silica layers. Transmission electron microscopy images showed that the thickness of the colloidal silica coating was about 700 nm, while that of the silica nanosheet coating was 30 nm. There was one drawback to using silica nanosheets, namely a deterioration in the core mechanical strength. Nevertheless, the silica nanosheet coating resulted in nanoscale-thick silica layers that are favorable for enhancing the electrical resistivity.

  16. 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

    CERN Document Server

    International Electrotechnical Commission. Geneva

    2001-01-01

    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.).

  17. Optimize awareness of hazards in underground coal mines caused by electrical ignitions and fires through appropriate training guidelines.

    CSIR Research Space (South Africa)

    Page, TPT

    1998-03-01

    Full Text Available The objective of the work reported in this document was to compile training guidelines to address the hazards arising from electrical ignitions and fires in underground coal mines. The resulting training guidelines, which contain recommended...

  18. A study of electrical field caused by transmission lines in alternate current; Estudo do campo eletrico provocado por linhas de transmissao em corrente alternada

    Energy Technology Data Exchange (ETDEWEB)

    Braz, Celso Pereira; Jardini, Jose Antonio

    1995-12-31

    There are many different methods to calculate the electric field, from simple expressions to tri dimensional computer calculus. The aim this paper is to compare a conventional method, based on Maxwell`s equations and another that uses the finite elements in two dimensions (FLUX2D). A preliminary analysis on the effect of the electric field on people who are near the transmission line (on ground) was carried out, as well as the phenomena caused on the conductor surface. Two programs were used to simulate the electric field in the transmission line. With the conventional program the electric field sensibility was verified in relation to some transmission lines parameters, such as the profile of the electric field on the ground and on the conductor surface. With the FLUX2D the ground and the surface conductor profiles were also checked. Part of the transmission line sustaining tower for the electric field calculus on the conductor was verified and simulated too. Whenever possible a comparison between the two programs was also performed. (author) 8 refs., 18 figs., 4 tabs.

  19. Nanoscale magnetization reversal caused by electric field-induced ion migration and redistribution in cobalt ferrite thin films.

    Science.gov (United States)

    Chen, Xinxin; Zhu, Xiaojian; Xiao, Wen; Liu, Gang; Feng, Yuan Ping; Ding, Jun; Li, Run-Wei

    2015-04-28

    Reversible nanoscale magnetization reversal controlled merely by electric fields is still challenging at the moment. In this report, first-principles calculation indicates that electric field-induced magnetization reversal can be achieved by the appearance of unidirectional magnetic anisotropy along the (110) direction in Fe-deficient cobalt ferrite (CoFe(2-x)O4, CFO), as a result of the migration and local redistribution of the Co(2+) ions adjacent to the B-site Fe vacancies. In good agreement with the theoretical model, we experimentally observed that in the CFO thin films the nanoscale magnetization can be reversibly and nonvolatilely reversed at room temperature via an electrical ion-manipulation approach, wherein the application of electric fields with appropriate polarity and amplitude can modulate the size of magnetic domains with different magnetizations up to 70%. With the low power consumption (subpicojoule) characteristics and the elimination of external magnetic field, the observed electric field-induced magnetization reversal can be used for the construction of energy-efficient spintronic devices, e.g., low-power electric-write and magnetic-read memories.

  20. Electrical installations technology

    CERN Document Server

    Whitfield, J F

    1968-01-01

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

  1. Can the direct cardiac effects of the electric pulses generated by the TASER X26 cause immediate or delayed sudden cardiac arrest in normal adults?

    Science.gov (United States)

    Ideker, Raymond E; Dosdall, Derek J

    2007-09-01

    There is only a small amount of experimental data about whether the TASER X26, a nonlethal weapon that delivers a series of brief electrical pulses to cause involuntary muscular contraction to temporarily incapacitate an individual, can initiate ventricular fibrillation to cause sudden cardiac arrest either immediately or sometime after its use. Therefore, this paper uses the fundamental law of electrostimulation and experimental data from the literature to estimate the likelihood of such events. Because of the short duration of the TASER pulses, the large duration of the cardiac cell membrane time constant, the small fraction of current from electrodes on the body surface that passes through the heart, and the resultant high pacing threshold from the body surface, the fundamental law of electrostimulation predicts that the TASER pulses will not stimulate an ectopic beat in the large majority of normal adults. Since the immediate initiation of ventricular fibrillation in a normal heart requires a very premature stimulated ectopic beat and the threshold for such premature beats is higher than less premature beats, it is unlikely that TASER pulses can immediately initiate ventricular fibrillation in such individuals through the direct effect of the electric field generated through the heart by the TASER. In the absence of preexisting heart disease, the delayed development of ventricular fibrillation requires the electrical stimuli to cause electroporation or myocardial necrosis. However, the electrical thresholds for electroporation and necrosis are many times higher than that required to stimulate an ectopic beat. Therefore, it is highly unlikely that the TASER X26 can cause ventricular fibrillation minutes to hours after its use through direct cardiac effects of the electric field generated by the TASER.

  2. Gas insulated substations

    CERN Document Server

    2014-01-01

    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, ...

  3. A magnetic heterostructure of topological insulators as a candidate for an axion insulator.

    Science.gov (United States)

    Mogi, M; Kawamura, M; Yoshimi, R; Tsukazaki, A; Kozuka, Y; Shirakawa, N; Takahashi, K S; Kawasaki, M; Tokura, Y

    2017-05-01

    The axion insulator which may exhibit an exotic quantized magnetoelectric effect is one of the most interesting quantum phases predicted for the three-dimensional topological insulator (TI). The axion insulator state is expected to show up in magnetically doped TIs with magnetizations pointing inwards and outwards from the respective surfaces. Towards the realization of the axion insulator, we here engineered a TI heterostructure in which magnetic ions (Cr) are modulation-doped only in the vicinity of the top and bottom surfaces of the TI ((Bi,Sb)2Te3) film. A separation layer between the two magnetic layers weakens interlayer coupling between them, enabling the magnetization reversal of individual layers. We demonstrate the realization of the axion insulator by observing a zero Hall plateau (ZHP) (where both the Hall and longitudinal conductivity become zero) in the electric transport properties, excluding the other possible origins for the ZHP. The manifestation of the axion insulator can lead to a new stage of research on novel magnetoelectric responses in topological matter.

  4. Multifactor Stress Aging of Electrical Insulation

    Science.gov (United States)

    1990-11-29

    spaciai A- ---I--C alI RESEARCH OBJECTIVES To establish a physical and experimental base in order to study and understand multifactor stress (radiation...for their support and also to Maxwell Laboratories for winding the capacitors for this project. REFERENCES 1. J.R. Laghad and A. Hammoud , "A Brief...the Crystalline Content of Irradiated Linear Polyethylene Upon Ageing," Polymer, Vol. 23, pp.654-655, 1982. 17. A. N. Hammoud , J. R. Laghari and B

  5. Pure spin current devices based on ferromagnetic topological insulators

    Science.gov (United States)

    Götte, Matthias; Joppe, Michael; Dahm, Thomas

    2016-01-01

    Two-dimensional topological insulators possess two counter propagating edge channels with opposite spin direction. Recent experimental progress allowed to create ferromagnetic topological insulators realizing a quantum anomalous Hall (QAH) state. In the QAH state one of the two edge channels disappears due to the strong ferromagnetic exchange field. We investigate heterostructures of topological insulators and ferromagnetic topological insulators by means of numerical transport calculations. We show that spin current flow in such heterostructures can be controlled with high fidelity. Specifically, we propose spintronic devices that are capable of creating, switching and detecting pure spin currents using the same technology. In these devices electrical currents are directly converted into spin currents, allowing a high conversion efficiency. Energy independent transport properties in combination with large bulk gaps in some topological insulator materials may allow operation even at room temperature. PMID:27782187

  6. Perioperative thermal insulation.

    Science.gov (United States)

    Bräuer, Anselm; Perl, Thorsten; English, Michael J M; Quintel, Michael

    2007-01-01

    Perioperative hypothermia remains a common problem during anesthesia and surgery. Unfortunately, the implementation of new minimally invasive surgical procedures has not lead to a reduction of this problem. Heat losses from the skin can be reduced by thermal insulation to avoid perioperative hypothermia. However, only a small amount of information is available regarding the physical properties of insulating materials used in the Operating Room (OR). Therefore, several materials using validated manikins were tested. Heat loss from the surface of the manikin can be described as:"Q = h . DeltaT . A" where Q = heat flux, h = heat exchange coefficient, DeltaT = temperature gradient between the environment and surface, and A = covered area. Heat flux per unit area and surface temperature were measured with calibrated heat flux transducers. Environmental temperature was measured using a thermoanemometer. The temperature gradient between the surface and environment (DeltaT) was varied and "h" was determined by linear regression analysis as the slope of "DeltaT" versus heat flux per unit area. The reciprocal of the heat exchange coefficient defines the insulation. The insulation values of the materials varied between 0.01 Clo (plastic bag) to 2.79 Clo (2 layers of a hospital duvet). Given the range of insulating materials available for outdoor activities, significant improvement in insulation of patients in the OR is both possible and desirable.

  7. The electro-mechanical effect from charge dynamics on polymeric insulation lifetime

    Directory of Open Access Journals (Sweden)

    H. Alghamdi

    2015-12-01

    Full Text Available For polymeric material used as electrical insulation, the presence of space charges could be the consequence of material degradations that are thermally activated but increased by the application of an electric field. The dynamics of space charge, therefore, can be potentially used to characterize the material. In this direction, a new aging model in which parameters have clear physical meanings has been developed and applied to the material to extrapolate the lifetime. The kinetic equation has been established based on charge trapping and detrapping of the injected charge from the electrodes. The local electromechanical energy stored in the region surrounding the trap is able to reduce the trap-depth with a value related to the electric field. At a level where the internal electric field exceeds the detrapping field in the material, an electron can be efficiently detrapped and the released energy from detrapping process can cause a weak bond or chain scission i.e. material degradation. The model has been applied to the electro-thermally aged low density polyethylene film samples, showing well fitted result, as well as interesting relationships between parameter estimates and insulation morphology.

  8. The electro-mechanical effect from charge dynamics on polymeric insulation lifetime

    Energy Technology Data Exchange (ETDEWEB)

    Alghamdi, H., E-mail: haalghamdi@nu.edu.sa [Faculty of Physical Sciences and Engineering, University of Southampton, Southampton, SO17 1BJ (United Kingdom); Faculty of Engineering, Najran University, Najran, P.O.Box 1988 (Saudi Arabia); Chen, G.; Vaughan, A. S. [Faculty of Physical Sciences and Engineering, University of Southampton, Southampton, SO17 1BJ (United Kingdom)

    2015-12-15

    For polymeric material used as electrical insulation, the presence of space charges could be the consequence of material degradations that are thermally activated but increased by the application of an electric field. The dynamics of space charge, therefore, can be potentially used to characterize the material. In this direction, a new aging model in which parameters have clear physical meanings has been developed and applied to the material to extrapolate the lifetime. The kinetic equation has been established based on charge trapping and detrapping of the injected charge from the electrodes. The local electromechanical energy stored in the region surrounding the trap is able to reduce the trap-depth with a value related to the electric field. At a level where the internal electric field exceeds the detrapping field in the material, an electron can be efficiently detrapped and the released energy from detrapping process can cause a weak bond or chain scission i.e. material degradation. The model has been applied to the electro-thermally aged low density polyethylene film samples, showing well fitted result, as well as interesting relationships between parameter estimates and insulation morphology.

  9. High temperature study of flexible silicon-on-insulator fin field-effect transistors

    KAUST Repository

    Diab, Amer El Hajj

    2014-09-29

    We report high temperature electrical transport characteristics of a flexible version of the semiconductor industry\\'s most advanced architecture: fin field-effect transistor on silicon-on-insulator with sub-20 nm fins and high-κ/metal gate stacks. Characterization from room to high temperature (150 °C) was completed to determine temperature dependence of drain current (Ids), gate leakage current (Igs), transconductance (gm), and extracted low-field mobility (μ0). Mobility degradation with temperature is mainly caused by phonon scattering. The other device characteristics show insignificant difference at high temperature which proves the suitability of inorganic flexible electronics with advanced device architecture.

  10. Reclaiming fiberglass from faced insulation batts

    Science.gov (United States)

    In the manufacture of paper-backed fiberglass insulation, defects may occur that cause the manufacturer to reject approximately 45 metric tons (50 tons) of material on average each month. This material is currently hauled to a landfill, placing both a financial burden on the company and an environm...

  11. Risk assessment of desert pollution on composite high voltage insulators.

    Science.gov (United States)

    El-Shahat, Mohammed; Anis, Hussein

    2014-09-01

    Transmission lines located in the desert are subjected to desert climate, one of whose features is sandstorms. With long accumulation of sand and with the advent of moisture from rain, ambient humidity and dew, a conductive layer forms and the subsequent leakage current may lead to surface discharge, which may shorten the insulator life or lead to flashover thus interrupting the power supply. Strategically erected power lines in the Egyptian Sinai desert are typically subject to such a risk, where sandstorms are known to be common especially in the spring. In view of the very high cost of insulator cleaning operation, composite (silicon rubber) insulators are nominated to replace ceramic insulators on transmission lines in Sinai. This paper examines the flow of leakage current on sand-polluted composite insulators, which in turn enables a risk assessment of insulator failure. The study uses realistic data compiled and reported in an earlier research project about Sinai, which primarily included grain sizes of polluting sand as well as their salinity content. The paper also uses as a case study an ABB-designed composite insulator. A three-dimensional finite element technique is used to simulate the insulator and seek the potential and electric field distribution as well as the resulting leakage current flow on its polluted surface. A novel method is used to derive the probabilistic features of the insulator's leakage current, which in turn enables a risk assessment of insulator failure. This study is expected to help in critically assessing - and thus justifying - the use of this type of insulators in Sinai and similar critical areas.

  12. Metal-insulator and charge ordering transitions in oxide nanostructures

    Science.gov (United States)

    Singh, Sujay Kumar

    Strongly correlated oxides are a class of materials wherein interplay of various degrees of freedom results in novel electronic and magnetic phenomena. Vanadium oxides are widely studied correlated materials that exhibit metal-insulator transitions (MIT) in a wide temperature range from 70 K to 380 K. In this Thesis, results from electrical transport measurements on vanadium dioxide (VO2) and vanadium oxide bronze (MxV 2O5) (where M: alkali, alkaline earth, and transition metal cations) are presented and discussed. Although the MIT in VO2 has been studied for more than 50 years, the microscopic origin of the transition is still debated since a slew of external parameters such as light, voltage, and strain are found to significantly alter the transition. Furthermore, recent works on electrically driven switching in VO2 have shown that the role of Joule heating to be a major cause as opposed to electric field. We explore the mechanisms behind the electrically driven switching in single crystalline nanobeams of VO2 through DC and AC transport measurements. The harmonic analysis of the AC measurement data shows that non-uniform Joule heating causes electronic inhomogeneities to develop within the nanobeam and is responsible for driving the transition in VO2. Surprisingly, field assisted emission mechanisms such as Poole-Frenkel effect is found to be absent and the role of percolation is also identified in the electrically driven transition. This Thesis also provides a new insight into the mechanisms behind the electrolyte gating induced resistance modulation and the suppression of MIT in VO2. We show that the metallic phase of VO2 induced by electrolyte gating is due to an electrochemical process and can be both reversible and irreversible under different conditions. The kinetics of the redox processes increase with temperature; a complete suppression of the transition and the stabilization of the metallic phase are achievable by gating in the rutile metallic phase

  13. Economical noise- and heat insulation

    Energy Technology Data Exchange (ETDEWEB)

    1982-06-01

    All noise protection and heat insulations measures are interlinked. While noise abatement and insulation is primarily a task of health protection, the economically optimised heat insulation is rather a problem for financial mathematics. Parameters, influencing the heat insulation are subject to changes which will affect the profitability of heat insulation measures in turn. Several options for reducing the noise level are described and some standard values for material cost are supplied. Depending on the kind of noise different abatement methods are suitable which require materials with specific properties. Measures for heat insulation are described which to a great extent are identical will noise abatement measures.

  14. Assessing clogging processes caused by biofilm growth and organic particle accumulation in constructed wetlands using time-lapse electrical resistivity tomography method

    Science.gov (United States)

    Mahjoub, Himi; Tapias, Josefina C.; Lovera, Raúl; Rivero, Lluís; Font, Xavier; Casas, Albert

    2016-04-01

    Constructed wetlands for removing pollutants from wastewater in small communities are growing rapidly in many regions of the world. The advantages over conventional mechanical sanitation systems, where land availability is not a limiting factor, are low energy requirements, easy operation and maintenance, low sludge production and cost-effectivity. Nevertheless, with time the cleaning process can result in gradual clogging of the porous layer by suspended solids, bacterial film, chemical precipitates and compaction. The clogging development causes decrease of hydraulic conductivity, reduced oxygen supply and further leads to a rapid decrease of the treatment performance. As the investment involved in reversing clogging can represent a substantial fraction of the cost of a new system it is essential to assess in advance the evolution of clogging process and detect potential failures in the system. Since there is a lack of experiences for monitoring the functionality of constructed wetlands time-lapse electrical resistivity tomography studies have been conducted at horizontal sub-surface flow municipal wastewater treatment wetlands of Catalonia (Spain). The results of this research show that electrical resistivity tomography can be a very useful technique for assessing the extent of silting up processes that clog the subsurface flow constructed wetlands through the gravel layer. In the unsaturated zone, the electrical resistivity is greater at the end of the filter, since the pores contains air which is dielectric, while at the beginning of the filter the resistivity is lower because the electrical conduction of organic matter around the mineral grains. Conversely, in the saturated zone, the electrical resistivity is lower at the end of the filter, since pores contain a higher proportion of high ionic conductivity wastewater, while at the beginning of the filter the electrical resistivity is higher because of the lower porosity due to the clogging process.

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

    NARCIS (Netherlands)

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

    2011-01-01

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

  16. ASRM Case Insulation development

    Science.gov (United States)

    Tam, W. F. S.; Bell, M.

    1993-06-01

    The ASRM Case Insulation Program used design of experiments to develop a high performance case insulation. The program traded-off more than thirty properties in areas of ablation performance, material properties, processibility, bonding/aging. Kevlar pulp was found to be the most significant factor. The low-molecular weight ethylene propylene diene monomer, EPDM was the second most significant factor. The curative was the third most significant factor. The tackifier was the fourth most significant factor. The stripwinding process for applying the insulation onto the case inner surfaces was also studied. The parameters selected for experiment were extruder speed, upper roller temperature and extruder nozzle temperature. The extrudability results showed that non-Kevlar filled formulations displayed optimum edges but poor thickness continuity. High Kevlar filled formulations displayed optimum thickness continuity but poor strip edge ratings.

  17. CERTIFICATION OF THE RADIATION RESISTANCE OF COIL INSULATION MATERIAL

    CERN Document Server

    Polinski, J; Bogdan, P

    2013-01-01

    The goal of the WP 7.2.1 sub-task of the EuCARD program has been to determine the Nb3Sn based accelerator magnet coil electrical insulation resistance against irradiation, which will occur in future accelerators. The scope of the certification covers determination of mechanical, electrical and thermal properties changes due to irradiation. The report presents a selection of the insulation material candidates for future accelerator magnets as well as the definition of the radiation certification methodology with respect of radiation type, energy, doses and irradiation conditions. The test methods and results of the electrical and mechanical insulation materials properties degradation due to irradiation are presented. Thermal conductivity and Kapitza resistance at temperature range from 1.5 K to 2.0 K (superfluid helium conditions) are given.

  18. Thermal Insulation Strips Conserve Energy

    Science.gov (United States)

    2009-01-01

    Launching the space shuttle involves an interesting paradox: While the temperatures inside the shuttle s main engines climb higher than 6,000 F hot enough to boil iron for fuel, the engines use liquid hydrogen, the second coldest liquid on Earth after liquid helium. Maintained below 20 K (-423 F), the liquid hydrogen is contained in the shuttle s rust-colored external tank. The external tank also contains liquid oxygen (kept below a somewhat less chilly 90 K or -297 F) that combines with the hydrogen to create an explosive mixture that along with the shuttle s two, powdered aluminum-fueled solid rocket boosters allows the shuttle to escape Earth s gravity. The cryogenic temperatures of the main engines liquid fuel can cause ice, frost, or liquefied air to build up on the external tank and other parts of the numerous launch fueling systems, posing a possible debris risk when the ice breaks off during launch and causing difficulties in the transfer and control of these cryogenic liquid propellants. Keeping the fuel at the necessary ultra-cold temperatures while minimizing ice buildup and other safety hazards, as well as reducing the operational maintenance costs, has required NASA to explore innovative ways for providing superior thermal insulation systems. To address the challenge, the Agency turned to an insulating technology so effective that, even though it is mostly air, a thin sheet can prevent a blowtorch from igniting a match. Aerogels were invented in 1931 and demonstrate properties that make them the most extraordinary insulating materials known; a 1-inch-thick piece of aerogel provides the same insulation as layering 15 panes of glass with air pockets in between. Derived from silica, aluminum oxide, or carbon gels using a supercritical drying process - resulting in a composition of almost 99-percent air - aerogels are the world s lightest solid (among 15 other titles they hold in the Guinness World Records), can float indefinitely on water if treated to be

  19. Insulation materials. Cellulose fiber and Expanded polystyrene Insulations

    OpenAIRE

    Viladot Bel, Cèlia

    2017-01-01

    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...

  20. Insulation materials. Cellulose fiber and expanded polystyrene insulations

    OpenAIRE

    Viladot Bel, Cèlia

    2017-01-01

    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...

  1. Super insulating aerogel glazing

    DEFF Research Database (Denmark)

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

    2004-01-01

    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...

  2. Condensation in insulated homes

    Energy Technology Data Exchange (ETDEWEB)

    Wiley, R A

    1978-05-28

    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)

  3. Tetradymites as thermoelectrics and topological insulators

    Science.gov (United States)

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

    2017-10-01

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

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

    Directory of Open Access Journals (Sweden)

    Jian Li

    2011-10-01

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

  5. Design and Construction of a Live Insulator Washing System for Transformers

    Directory of Open Access Journals (Sweden)

    Lizama-Cámara Y.A.

    2012-04-01

    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.

  6. Electric field induced salt precipitation into activated carbon air-cathode causes power decay in microbial fuel cells.

    Science.gov (United States)

    An, Jingkun; Li, Nan; Wan, Lili; Zhou, Lean; Du, Qing; Li, Tian; Wang, Xin

    2017-10-15

    As a promising design for the real application of microbial fuel cells (MFCs) in wastewater treatment, activated carbon (AC) air-cathode is suffering from a serious power decay after long-term operation. However, the decay mechanism is still not clear because of the complex nature of contaminations. Different from previous reports, we found that local alkalinization and natural evaporation had an ignorable effect on cathode performance (∼2% decay on current densities), while electric field induced salt precipitation (∼53%) and biofouling (∼37%) were dominant according to the charge transfer resistance, which decreased power desities by 36% from 1286 ± 30 to 822 ± 23 mW m -2 in 6 months. Biofouling can be removed by scrapping, however, electric field induced salt precipitation under biofilm still clogged 37% of specific area in catalyst layer, which was even seen to penetrate through the gas diffusion layer. Our findings provided a new insight of AC air-cathode performance decay, providing important information for the improvement of cathodic longevity in the future. Copyright © 2017 Elsevier Ltd. All rights reserved.

  7. Handbook of Thermal Insulation Applications.

    Science.gov (United States)

    1983-01-01

    Transfer in Low-Density Insulation." Journal of Thermal Insulation. Technomic Publishing Co., Inc. Vol. 1, pp. 37-61. July 1979. Rockwool Industries...Inc. "Blowing Wool" Technical Rulletins #6, #8, #9, and #10. Englewood, CO. Aug. 1981. Rockwool Industries, Inc. "Facts About Home Insulation." No...78120. Denver, CO. 1981. Rockwool Industries, Inc. "Multi-layer Foil." Technical Bulletin #5. Englewood, CO. Aug. 1981. Roofing, Siding and Insulation

  8. Self-Healing Wire Insulation

    Science.gov (United States)

    Parrish, Clyde F. (Inventor)

    2012-01-01

    A self-healing system for an insulation material initiates a self-repair process by rupturing a plurality of microcapsules disposed on the insulation material. When the plurality of microcapsules are ruptured, reactants within the plurality of microcapsules react to form a replacement polymer in a break of the insulation material. This self-healing system has the ability to repair multiple breaks in a length of insulation material without exhausting the repair properties of the material.

  9. Risk assessment of desert pollution on composite high voltage insulators

    Directory of Open Access Journals (Sweden)

    Mohammed El-Shahat

    2014-09-01

    Full Text Available Transmission lines located in the desert are subjected to desert climate, one of whose features is sandstorms. With long accumulation of sand and with the advent of moisture from rain, ambient humidity and dew, a conductive layer forms and the subsequent leakage current may lead to surface discharge, which may shorten the insulator life or lead to flashover thus interrupting the power supply. Strategically erected power lines in the Egyptian Sinai desert are typically subject to such a risk, where sandstorms are known to be common especially in the spring. In view of the very high cost of insulator cleaning operation, composite (silicon rubber insulators are nominated to replace ceramic insulators on transmission lines in Sinai. This paper examines the flow of leakage current on sand-polluted composite insulators, which in turn enables a risk assessment of insulator failure. The study uses realistic data compiled and reported in an earlier research project about Sinai, which primarily included grain sizes of polluting sand as well as their salinity content. The paper also uses as a case study an ABB-designed composite insulator. A three-dimensional finite element technique is used to simulate the insulator and seek the potential and electric field distribution as well as the resulting leakage current flow on its polluted surface. A novel method is used to derive the probabilistic features of the insulator’s leakage current, which in turn enables a risk assessment of insulator failure. This study is expected to help in critically assessing – and thus justifying – the use of this type of insulators in Sinai and similar critical areas.

  10. Aerogels for Thermal Insulation of Thermoelectric Devices

    Science.gov (United States)

    Sakamoto, Jeffrey; Fleurial, Jean-Pierre; Snyder, Jeffrey; Jones, Steven; Caillat, Thierry

    2006-01-01

    carbon black, which absorbs infrared radiation. Another example of an opacifier is micron- sized metal flakes, which reflect infrared radiation. Encapsulation in cast aerogel insulation also can help prolong the operational lifetimes of thermoelectric devices that must operate in vacuum and that contain SiGe or such advanced skutterudite thermoelectric materials as CoSb3 and CeFe3.5Co0.5Sb12. The primary cause of deterioration of most thermoelectric materials is thermal decomposition or sublimation (e.g., sublimation of Sb from CoSb3) at typical high operating temperatures. Aerogel present near the surface of CoSb3 can impede the outward transport of Sb vapor by establishing a highly localized, equilibrium Sb vapor atmosphere at the surface of the CoSb3.

  11. THERMAL INSULATION SYSTEMS

    Science.gov (United States)

    Augustynowicz, Stanislaw D. (Inventor); Fesmire, James E. (Inventor)

    2005-01-01

    Thermal insulation systems and with methods of their production. The thermal insulation systems incorporate at least one reflection layer and at least one spacer layer in an alternating pattern. Each spacer layer includes a fill layer and a carrier layer. The fill layer may be separate from the carrier layer, or it may be a part of the carrier layer, i.e., mechanically injected into the carrier layer or chemically formed in the carrier layer. Fill layers contain a powder having a high surface area and low bulk density. Movement of powder within a fill layer is restricted by electrostatic effects with the reflection layer combined with the presence of a carrier layer, or by containing the powder in the carrier layer. The powder in the spacer layer may be compressed from its bulk density. The thermal insulation systems may further contain an outer casing. Thermal insulation systems may further include strips and seams to form a matrix of sections. Such sections serve to limit loss of powder from a fill layer to a single section and reduce heat losses along the reflection layer.

  12. The Polar Insulation Investigation

    Science.gov (United States)

    Urban-Rich, Juanita

    2006-01-01

    In this article, the author developed an activity called "The Polar Insulation Investigation." This activity builds on students' natural interest in "things polar" and introduces them to animal adaptations in a unique way. The aim of the exploration is to determine the role of animal coverings (e.g., blubber, fur, and feathers) and to see which is…

  13. Super insulating aerogel glazing

    DEFF Research Database (Denmark)

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

    2005-01-01

    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...

  14. Exploring Homeowners’ Insulation Activity

    NARCIS (Netherlands)

    Friege, J; Holtz, G; Chappin, E.J.L.

    2016-01-01

    Insulating existing buildings offers great potential for reducing greenhouse gas emissions and meeting Germany’s climate protection targets. Previous research suggests that, since homeowners’ decision-making processes are inadequately understood as yet, today’s incentives aiming at increasing

  15. Photonic topological insulators.

    Science.gov (United States)

    Khanikaev, Alexander B; Mousavi, S Hossein; Tse, Wang-Kong; Kargarian, Mehdi; MacDonald, Allan H; Shvets, Gennady

    2013-03-01

    Recent progress in understanding the topological properties of condensed matter has led to the discovery of time-reversal-invariant topological insulators. A remarkable and useful property of these materials is that they support unidirectional spin-polarized propagation at their surfaces. Unfortunately topological insulators are rare among solid-state materials. Using suitably designed electromagnetic media (metamaterials) we theoretically demonstrate a photonic analogue of a topological insulator. We show that metacrystals-superlattices of metamaterials with judiciously designed properties-provide a platform for designing topologically non-trivial photonic states, similar to those that have been identified for condensed-matter topological insulators. The interfaces of the metacrystals support helical edge states that exhibit spin-polarized one-way propagation of photons, robust against disorder. Our results demonstrate the possibility of attaining one-way photon transport without application of external magnetic fields or breaking of time-reversal symmetry. Such spin-polarized one-way transport enables exotic spin-cloaked photon sources that do not obscure each other.

  16. Beyond insulation and isolation

    DEFF Research Database (Denmark)

    Højlund, Marie Koldkjær

    2016-01-01

    are insulation and isolation strategies to reduce measurable and perceptual noise levels. However, these strategies do not actively support the need to feel like an integral part of the shared hospital environment, which is a key element in creating healing environments, according to the paradigm of Evidence...

  17. Peg supported thermal insulation panel

    Science.gov (United States)

    Nowobilski, Jeffert J.; Owens, William J.

    1985-01-01

    A thermal insulation panel which is lightweight, load bearing, accommodates thermal stress, and has excellent high temperature insulation capability comprising high performance insulation between thin metal walls supported by high density, high strength glass pegs made in compliance with specified conditions of time, temperature and pressure.

  18. Cable Insulation Scheme to Improve Heat Transfer to Superfluid Helium in Nb-Ti Accelerator Magnets

    OpenAIRE

    La China, M; Tommasini, D

    2008-01-01

    In superconducting magnets operating at high heat loads as the ones for interaction region of particle colliders or for fast cycling synchrotrons, the limited heat transfer capability of state-of-the-art electrical insulation may constitute a heavy limitation to performance. In the LHC main magnets, Nb-Ti epoxy-free insulation, composed of polyimide tapes, has proved to be permeable to superfluid helium, however the heat flux is rather limited. After a review of the standard insulation scheme...

  19. Thermal insulation properties of walls

    Directory of Open Access Journals (Sweden)

    Zhukov Aleksey Dmitrievich

    2014-05-01

    Full Text Available Heat-protective qualities of building structures are determined by the qualities of the used materials, adequate design solutions and construction and installation work of high quality. This rule refers both to the structures made of materials similar in their structure and nature and mixed, combined by a construction system. The necessity to ecaluate thermal conductivity is important for a product and for a construction. Methods for evaluating the thermal protection of walls are based on the methods of calculation, on full-scale tests in a laboratory or on objects. At the same time there is a reason to believe that even deep and detailed calculation may cause deviation of the values from real data. Using finite difference method can improve accuracy of the results, but it doesn’t solve all problems. The article discusses new approaches to evaluating thermal insulation properties of walls. The authors propose technique of accurate measurement of thermal insulation properties in single blocks and fragments of walls and structures.

  20. Economical analysis of determination thermal insulation thickness for different external walls

    Directory of Open Access Journals (Sweden)

    Ali Etem Gürel

    2011-06-01

    Full Text Available In the countries which supply big amount of their energy needs by import like Turkey using the energy economically is important. Thermal insulation technologies in buildings are the main method for using energy economically. But choosing the thickness of the insulation material redundant causes high insulation costs. For this reason, an optimum point which provides the highest price in insulation applications is the subject. In this study, different building materials (horizontal perforated brick and gas concrete, and isolated forms of insulation (exterior insulation and insulation sandwich was a model of a building exterior wall. The study determined that the wall and the heat loss through the life-cost analysis, according to the present calculations (LCCA, the optimum thickness of insulation, energy savings and payback periods were determined.

  1. Study of Composite Insulator Sheds Subjected to Wheel Test

    Directory of Open Access Journals (Sweden)

    Mackiewicz M.

    2017-06-01

    Full Text Available The paper presents investigation of the properties of the surface and the material stiffness – flexibility of series of samples taken from the sheds of the composite insulators. The insulators were previously subjected to wheel test. The wheel test and 1000 h salt fog test are regarded as alternative examination of the material resistance to the effects of electrical surface discharges. There were investigated two series of the samples of the composite insulators sheds. Examined specimens, made of HTV silicone rubber, were taken from the sheds of medium-voltage composite insulators of two different manufacturers. Insulators of both types passed the 1000 h salt fog test without reservation. Meanwhile, the wheel test can provide a basis for better distinguishing between physical properties of the tested materials. In the case of the insulators of one of the manufacturers the wheel test result was negative. Cross puncture effect of the sheds took place in several places. In addition, sheds were covered with dark coating of varying thicknesses. The results of the study indicated a significantly stronger influence of electrical and temperature factors on the sheds under investigations during the wheel test than in the case of the 1000 h salt fog test. It can be stated that these tests cannot be considered as alternative and it seems that wheel test enables better distinguishing between properties of the materials.

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

    Directory of Open Access Journals (Sweden)

    Lei Lan

    2017-07-01

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

  3. Anomalous photoelectric effect of a polycrystalline topological insulator film.

    Science.gov (United States)

    Zhang, Hongbin; Yao, Jiandong; Shao, Jianmei; Li, Hai; Li, Shuwei; Bao, Dinghua; Wang, Chengxin; Yang, Guowei

    2014-07-29

    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.

  4. Polyimide/Glass Composite High-Temperature Insulation

    Science.gov (United States)

    Pater, Ruth H.; Vasquez, Peter; Chatlin, Richard L.; Smith, Donald L.; Skalski, Thomas J.; Johnson, Gary S.; Chu, Sang-Hyon

    2009-01-01

    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.

  5. Dynamical preparation of Floquet Chern insulators.

    Science.gov (United States)

    D'Alessio, Luca; Rigol, Marcos

    2015-10-01

    Realizing topological insulators is of great current interest because of their remarkable properties and possible future applications. There are recent proposals based on Floquet analyses that one can generate topologically non-trivial insulators by periodically driving topologically trivial ones. Here we address what happens if one follows the dynamics in such systems. Specifically, we present an exact study of the time evolution of a graphene-like system subjected to a circularly polarized electric field. We prove that for infinite (translationally invariant) systems the Chern number is conserved under unitary evolution. For systems with boundaries, on the other hand, we show that a properly defined topological invariant, the Bott index, can change. Hence, it should be possible to experimentally prepare topological states starting from non-topological ones. We show that the chirality of the edge current in such systems can be controlled by adjusting the filling.

  6. Industrial thermal insulation: an assessment

    Energy Technology Data Exchange (ETDEWEB)

    Donnelly, R.G.; Tennery, V.J.; McElroy, D.L.; Godfrey, T.G.; Kolb, J.O.

    1976-03-01

    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.

  7. Using fiberglass volumes for VPI of superconductive magnetic systems' insulation

    Science.gov (United States)

    Andreev, I. S.; Bezrukov, A. A.; Bursikov, A. S.; Klimchenko, Y. A.; Marushin, E. L.; Mednikov, A. A.; Pischugin, A. B.; Rodin, I. Y.; Stepanov, D. B.

    2014-01-01

    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.

  8. A Method of Insulator Detection from Aerial Images

    Directory of Open Access Journals (Sweden)

    Yongjie Zhai

    2014-08-01

    Full Text Available With increased image processing and sensor technologies, it is possible for photogrammetrists to monitor the status of electrical power infrastructures. Identifying and extracting insulators from complex background have great potential in automatic power grid surveillance on board unmanned aerial vehicles. This paper proposes an improved method to automatically extract the insulators from aerial images. A 3D model is introduced into the existing algorithms to obtain samples of insulators, which are Haar features and AdaBoost. Finally, in order to evaluate the performances, we compare our 3D model-based method with the existing methods that does not use 3D model to show the performance improvement. The experimental results demonstrate that the proposed method is able to successfully extract the insulators from aerial images with an increased average detection ratio to 83 %.

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

    Science.gov (United States)

    Broadhurst, John H.

    1989-01-01

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

  10. Study on the lightning impulse breakdown characteristics of gaseous insulation media for the design of a high voltage superconducting apparatus

    Science.gov (United States)

    Kang, H.; Na, J. B.; Ahn, M. C.; Bae, D. K.; Kim, Y. H.; Ko, T. K.

    2010-11-01

    In general, the current leads of high voltage superconducting apparatuses cooled by liquid nitrogen are exposed to gaseous insulation media. Therefore, the investigation on the electrical breakdown characteristics of gaseous insulation media should be performed to develop electrically reliable high voltage superconducting power apparatuses. In this study, the lightning impulse breakdown tests on gaseous insulation media are conducted by using sphere-to-plane electrode systems made of stainless steel. Also, the lightning impulse breakdown voltage tests on gaseous insulation media according to various pressures are performed. The experimental results show that the electrical breakdown characteristics under lightning impulse voltage are affected by the gap length between electrode systems, the size of electrodes, and the field utilization factors. From these results, the electrical insulation design criteria to estimate the electrical breakdown voltage are established. The results are expected to be applicable to the design of current leads for high voltage superconducting apparatuses.

  11. Effects of Electron-Cyclotron-Resonance Oxygen Plasma Irradiation on Properties of Insulator/Ge-Semiconductor Interfaces Prior to Germanium Nitride Formation

    Science.gov (United States)

    Otani, Yohei; Fukuda, Yukio; Sato, Tetsuya; Nakagawa, Kiyokazu; Toyota, Hiroshi; Ono, Toshiro

    2008-09-01

    Electron-cyclotron-resonance (ECR) oxygen (O2) plasma was irradiated onto the surface of germanium (Ge) substrates prior to germanium nitride (GeNx) formation. Germanium metal-insulator-semiconductor (Ge-MIS) structures with a 5-nm-thick silicon nitride/2-nm-thick GeNx gate insulator stack fabricated by ECR plasma nitridation and sputtering deposition without substrate heating were electrically and physically characterized. Although ECR O2 plasma irradiation onto the surface of Ge substrates caused no significant difference in the chemical state of GeNx/Ge interfaces in X-ray photoemission spectroscopic measurement, irradiation for an appropriate period improved the state of GeNx/Ge interfaces and the electrical properties of Ge-MIS.

  12. Recessed insulator and barrier AlGaN/GaN HEMT: A novel structure ...

    Indian Academy of Sciences (India)

    In this study, a gallium nitride (GaN) high electron mobility transistor (HEMT) with recessed insulator and barrier is reported. In the proposed structure, insulator is recessed into the barrier at the drain side and barrier is recessed into the buffer layer at the source side. We study important device characteristics such as electric ...

  13. Effect of Flow Direction on the Extinction Limit for Flame Spread over Wire Insulation in Microgravity

    DEFF Research Database (Denmark)

    Nagachi, Masashi; Mitsui, Fumiya; Citerne, Jean-Marie

    Experiments to determine the Limiting Oxygen Concentration (LOC) of a flame spread over electric wire insulation were carried out in microgravity provided by parabolic flights. The difference between the LOC in opposed and concurrent flows was evidenced. Polyethylene insulated Copper (Cu) wires a...

  14. OPERATIONAL FACTORS AFFECTING THE PERFORMANCE OF CONTINUOUS MONITORING SYSTEM OF TRANSFORMER EQUIPMENT INSULATION

    Directory of Open Access Journals (Sweden)

    A. G. Spitsa

    2013-07-01

    Full Text Available To ensure the required level of high voltage electrical networks reliability, special attention should be paid to the equipment technical condition monitoring and diagnosis. The periodic monitoring can only reduce the probability of device damaging. The time period between the insulation defect appearance and the device damage can be considerably less than the time interval between measurements recommended by the Testing norms and recommendations for each type of equipment. This demonstrates the lack of effectiveness of the systems of technical diagnostics and large time interval between tests. Continuous monitoring systems are free from these disadvantages. The article covers the results of the insulation continuous monitoring of current transformers and bushings at substation 330 kV «Dnipro-Donbass» Dnieper Power System. Operational factors affecting the reliability of the results are considered, and detailed analysis of errors caused by isolating transformers is given. The article describes methods and recommendations elaborated for mitigation of operational factors impact on the insulation continuous monitoring system. It should be noted that systems of continuous monitoring of transformer equipment under operating voltage are relatively new. Their implementation at the power facilities is at the initial stage. As a result, there is no reliable information on such systems operating experience. Therefore, the investigations covered by this article can be of practical value for both continuous monitoring system developers and operating personnel.

  15. Poor electronic screening in lightly doped Mott insulators observed with scanning tunneling microscopy

    Science.gov (United States)

    Battisti, I.; Fedoseev, V.; Bastiaans, K. M.; de la Torre, A.; Perry, R. S.; Baumberger, F.; Allan, M. P.

    2017-06-01

    The effective Mott gap measured by scanning tunneling microscopy (STM) in the lightly doped Mott insulator (Sr1-xLax) 2IrO4 differs greatly from values reported by photoemission and optical experiments. Here we show that this is a consequence of the poor electronic screening of the tip-induced electric field in this material. Such effects are well known from STM experiments on semiconductors and go under the name of tip-induced band bending (TIBB). We show that this phenomenon also exists in the lightly doped Mott insulator (Sr1-xLax) 2IrO4 and that, at doping concentrations of x ≤4 % , it causes the measured energy gap in the sample density of states to be bigger than the one measured with other techniques. We develop a model able to retrieve the intrinsic energy gap leading to a value which is in rough agreement with other experiments, bridging the apparent contradiction. At doping x ≈5 % we further observe circular features in the conductance layers that point to the emergence of a significant density of free carriers in this doping range and to the presence of a small concentration of donor atoms. We illustrate the importance of considering the presence of TIBB when doing STM experiments on correlated-electron systems and discuss the similarities and differences between STM measurements on semiconductors and lightly doped Mott insulators.

  16. Lattice QCD with strong external electric fields

    OpenAIRE

    Yamamoto, Arata

    2012-01-01

    We study particle generation by a strong electric field in lattice QCD. To avoid the sign problem of the Minkowskian electric field, we adopt the "isospin" electric charge. When a strong electric field is applied, the insulating vacuum is broken down and pairs of charged particles are produced by the Schwinger mechanism. The competition against the color confining force is also discussed.

  17. 30 CFR 77.1914 - Electrical equipment.

    Science.gov (United States)

    2010-07-01

    .... (b) The insulation of all electric conductors employed below the collar of any slope or shaft during... 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...

  18. 30 CFR 56.12004 - Electrical conductors.

    Science.gov (United States)

    2010-07-01

    ... 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. ...

  19. 30 CFR 57.12004 - Electrical conductors.

    Science.gov (United States)

    2010-07-01

    ... 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 shall...

  20. The metal-insulator transition in the organic conductor β″-(BEDT-TTF)2Hg(SCN)2Cl

    Science.gov (United States)

    Li, Weiwu; Rose, Eva; Tran, Minh Vu; Hübner, Ralph; Łapiński, Andrzej; Świetlik, Roman; Torunova, Svetlana A.; Zhilyaeva, Elena I.; Lyubovskaya, Rimma N.; Dressel, Martin

    2017-08-01

    We explore the nature of the metal-insulator transition in the two-dimensional organic compound β″-(BEDT-TTF)2Hg(SCN)2Cl by x-ray, electrical transport, ESR, Raman, and infrared investigations. Magnetic and vibrational spectroscopy concurrently reveal a gradual dimerization along the stacking direction (a -b ) , setting in already at the crossover temperature of 150 K from the metallic to the insulating state. A spin gap of Δσ=47 meV is extracted. From the activated resistivity behavior below T = 55 K, a charge gap of Δρ=60 meV is derived. At TCO = 72 K, the C=C vibrational modes reveal the development of a charge-ordered state with a charge disproportionation of 2 δρ=0.34 e . In addition to a slight structural dimerization, charge-order causes stripes most likely perpendicular to the stacks.

  1. Simulation of switching overvoltages in the mine electric power supply system

    Science.gov (United States)

    Ivanchenko, D. I.; Novozhilov, N. G.

    2017-02-01

    Overvoltages occur in mine power supply systems during switching off consumers with high inductive load, such as transformers, reactors and electrical machines. Overvoltages lead to an increase of insulation degradation rate and may cause electric faults, power outage, fire and explosion of methane and coal dust. This paper is dedicated to simulation of vacuum circuit breaker switching overvoltages in a mine power supply system by means of Simulink MATLAB. The model of the vacuum circuit breaker implements simulation of transient recovery voltage, current chopping and an electric arc. Obtained results were compared to available experimental data.

  2. Green insulation: hemp fibers

    Energy Technology Data Exchange (ETDEWEB)

    Anon

    2011-09-15

    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.

  3. Electrically floating, near vertical incidence, skywave antenna

    Energy Technology Data Exchange (ETDEWEB)

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

    2014-07-08

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

  4. Thermal Insulation Test Apparatuses

    Science.gov (United States)

    Berman, Brion

    2005-01-01

    The National Aeronautics and Space Administration (NASA) seeks to license its Thermal Insulation Test Apparatuses. Designed by the Cryogenics Test Laboratory at the John F. Kennedy Space Center (KSC) in Florida, these patented technologies (U.S. Patent Numbers: Cryostat 1 - 6,742,926, Cryostat 2 - 6,487,866, and Cryostat 4 - 6,824,306) allow manufacturers to fabricate and test cryogenic insulation at their production and/or laboratory facilities. These new inventions allow for the thermal performance characterization of cylindrical and flat specimens (e.g., bulk-fill, flat-panel, multilayer, or continuously rolled) over the full range of pressures, from high vacuum to no vacuum, and over the full range of temperatures from 77K to 300K. In today's world, efficient, low-maintenance, low-temperature refrigeration is taking a more significant role, from the food industry, transportation, energy, and medical applications to the Space Shuttle. Most countries (including the United States) have laws requiring commercially available insulation materials to be tested and rated by an accepted methodology. The new Cryostat methods go beyond the formal capabilities of the ASTM methods to provide testing for real systems, including full-temperature differences plus full-range vacuum conditions.

  5. Internal On-line Partial Discharge Analysis of 68.75 MVA Generator Stator Winding Insulation

    National Research Council Canada - National Science Library

    Waluyo Waluyo; Siti Saodah; Eltha Hidayatullah

    2016-01-01

    .... This phenomenon will be investigated by an electric field measurement in a measuring point. The internal partial discharge will give the insulation damage effect on a generator stator winding due to void existence...

  6. 30 CFR 56.12010 - Isolation or insulation of communication conductors.

    Science.gov (United States)

    2010-07-01

    ... 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. ...

  7. Regolith properties under trees and the biomechanical effects caused by tree root systems as recognized by electrical resistivity tomography (ERT)

    Science.gov (United States)

    Pawlik, Łukasz; Kasprzak, Marek

    2018-01-01

    Following previous findings regarding the influence of vascular plants (mainly trees) on weathering, soil production and hillslope stability, in this study, we attempted to test a hypothesis regarding significant impacts of tree root systems on soil and regolith properties. Different types of impacts from tree root system (direct and indirect) are commonly gathered under the key term of "biomechanical effects". To add to the discussion of the biomechanical effects of trees, we used a non-invasive geophysical method, electrical resistivity tomography (ERT), to investigate the profiles of four different configurations at three study sites within the Polish section of the Outer Western Carpathians. At each site, one long profile (up to 189 m) of a large section of a hillslope and three short profiles (up to 19.5 m), that is, microsites occupied by trees or their remnants, were made. Short profiles included the tree root zone of a healthy large tree, the tree stump of a decaying tree and the pit-and-mound topography formed after a tree uprooting. The resistivity of regolith and bedrock presented on the long profiles and in comparison with the short profiles through the microsites it can be seen how tree roots impact soil and regolith properties and add to the complexity of the whole soil/regolith profile. Trees change soil and regolith properties directly through root channels and moisture migration and indirectly through the uprooting of trees and the formation of pit-and-mound topography. Within tree stump microsites, the impact of tree root systems, evaluated by a resistivity model, was smaller compared to microsites with living trees or those with pit-and-mound topography but was still visible even several decades after the trees were windbroken or cut down. The ERT method is highly useful for quick evaluation of the impact of tree root systems on soils and regolith. This method, in contrast to traditional soil analyses, offers a continuous dataset for the entire

  8. Insulator - Insulator Contact Charging as a Function of Pressure

    Science.gov (United States)

    Hogue, Michael D.; Mucciolo, E. R.; Calle, C. I.

    2006-01-01

    Metal - metal and metal - insulator contact or triboelectric charging are well known phenomena with good theoretical understanding of the charge exchange mechanism. However, insulator - insulator charging is not as well understood. Theoretical and experimental research has been performed that shows that the surface charge on an insulator after triboelectric charging with another insulator is rapidly dissipated with lowered atmospheric pressure. This pressure discharge is consistent with surface ions being evaporated off the surface once their vapor pressure is attained. A two-phase equilibrium model based on an ideal gas of singly charged ions in equilibrium with a submonolayer adsorbed film was developed to describe the pressure dependence of the surface charge on an insulator. The resulting charge density equation is an electrostatic version of the Langmuir isotherm.

  9. A Seismic Analysis for Reflective Metal Insulation

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Kyuhyung; Kim, Taesoon [KHNP CRI, Daejeon (Korea, Republic of)

    2016-10-15

    U.S. NRC (Nuclear Regulatory Commission) GSI- 191 (Generic Safety Issue-191) is concerned about the head-loss of emergency core cooling pumps caused by calcium silicate insulation debris accumulated on a sump screen when a loss of coolant accident (LOCA). In order to cope with the concern, many nuclear plants in U. S. have been replacing calcium silicate insulation in containment building with reflective metal insulation (RMI). In Korea, RMI has been used for only reactor vessels recently constructed, but the RMI was imported. Therefore, we have been developing the domestic design of RMI to supply to nuclear power plants under operation and construction in relation to the GSI-191. This paper covers that the structural integrity of the RMI assembly was evaluated under SSE (safety shutdown earthquake) load. An analysis model was built for the seismic test system of a reflective metal insulation assembly and pre-stress, modal, and spectrum analysis for the model were performed using a commercial structural analysis code, ANSYS. According to the results of the analyses, the buckles fastening the RMIs showed the structural integrity under the required response spectrum containing the safety shutdown earthquake loads applied to main components in containment building. Consequently, since the RMI isn't disassembled under the SSE load, the RMI is judged not to affect safety related components.

  10. Behavior of AC High Voltage Polyamide Insulators: Evolution of Leakage Current in Different Surface Conditions

    Directory of Open Access Journals (Sweden)

    Mohammed El Amine Slama

    2015-01-01

    Full Text Available This paper is aimed at a systematic study of the leakage current of high voltage polyamide insulator string under different conditions of pollution for possible application in the electric locomotive systems. It is shown that in the case of clean/dry and clean/wetted insulators, the leakage current and applied voltage are linear. While in the case of pollution with saline spray, the leakage current and the applied voltage are not linear; the leakage current changes from a linear regime to a nonlinear regime up to total flashover of the insulators sting. Traces of erosion and tracking of insulators resulting of partial discharges are observed.

  11. Chemical oxidation of cable insulating oil contaminated soil

    NARCIS (Netherlands)

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

    2011-01-01

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

  12. Deletion of Kvβ1.1 subunit leads to electrical and haemodynamic changes causing cardiac hypertrophy in female murine hearts.

    Science.gov (United States)

    Tur, Jared; Chapalamadugu, Kalyan C; Padawer, Timothy; Badole, Sachin L; Kilfoil, Peter J; Bhatnagar, Aruni; Tipparaju, Srinivas M

    2016-04-01

    What is the central question of this study? The goal of this study was to evaluate sex differences and the role of the potassium channel β1 (Kvβ1) subunit in the heart. What is the main finding and its importance? Genetic ablation of Kvβ1.1 in females led to cardiac hypertrophy characterized by increased heart size, prolonged monophasic action potentials, elevated blood pressure and increased myosin heavy chain α (MHCα) expression. In contrast, male mice showed only electrical changes. Kvβ1.1 binds the MHCα isoform at the protein level, and small interfering RNA targeted knockdown of Kvβ1.1 upregulated MHCα. Cardiovascular disease is the leading cause of death and debility in women in the USA, and cardiac arrhythmias are a major concern. Voltage-gated potassium (Kv) channels along with the binding partners; Kvβ subunits are major regulators of the action potential (AP) shape and duration (APD). The regulation of Kv channels by the Kvβ1 subunit is unknown in female hearts. In the present study, we hypothesized that the Kvβ1 subunit is an important regulator of female cardiac physiology. To test this hypothesis, we ablated (knocked out; KO) the KCNAB1 isoform 1 (Kvβ1.1) subunit in mice and evaluated cardiac function and electrical activity by using ECG, monophasic action potential recordings and echocardiography. Our results showed that the female Kvβ1.1 KO mice developed cardiac hypertrophy, and the hearts were structurally different, with enlargement and increased area. The electrical derangements caused by Kvβ1.1 KO in female mice included long QTc and QRS intervals along with increased APD (APD20-90% repolarization). The male Kvβ1.1 KO mice did not develop cardiac hypertrophy, but they showed long QTc and prolonged APD. Molecular analysis showed that several genes that support cardiac hypertrophy were significantly altered in Kvβ1.1 KO female hearts. In particular, myosin heavy chain α expression was significantly elevated in Kvβ1.1 KO mouse

  13. Semiconductor of spinons: from Ising band insulator to orthogonal band insulator.

    Science.gov (United States)

    Farajollahpour, T; Jafari, S A

    2018-01-10

    We use the ionic Hubbard model to study the effects of strong correlations on a two-dimensional semiconductor. The spectral gap in the limit where on-site interactions are zero is set by the staggered ionic potential, while in the strong interaction limit it is set by the Hubbard U. Combining mean field solutions of the slave spin and slave rotor methods, we propose two interesting gapped phases in between: (i) the insulating phase before the Mott phase can be viewed as gapping a non-Fermi liquid state of spinons by the staggered ionic potential. The quasi-particles of underlying spinons are orthogonal to physical electrons, giving rise to the 'ARPES-dark' state where the ARPES gap will be larger than the optical and thermal gap. (ii) The Ising insulator corresponding to ordered phase of the Ising variable is characterized by single-particle excitations whose dispersion is controlled by Ising-like temperature and field dependences. The temperature can be conveniently employed to drive a phase transition between these two insulating phases where Ising exponents become measurable by ARPES and cyclotron resonance. The rare earth monochalcogenide semiconductors where the magneto-resistance is anomalously large can be a candidate system for the Ising band insulator. We argue that the Ising and orthogonal insulating phases require strong enough ionic potential to survive the downward renormalization of the ionic potential caused by Hubbard U.

  14. Semiconductor of spinons: from Ising band insulator to orthogonal band insulator

    Science.gov (United States)

    Farajollahpour, T.; Jafari, S. A.

    2018-01-01

    We use the ionic Hubbard model to study the effects of strong correlations on a two-dimensional semiconductor. The spectral gap in the limit where on-site interactions are zero is set by the staggered ionic potential, while in the strong interaction limit it is set by the Hubbard U. Combining mean field solutions of the slave spin and slave rotor methods, we propose two interesting gapped phases in between: (i) the insulating phase before the Mott phase can be viewed as gapping a non-Fermi liquid state of spinons by the staggered ionic potential. The quasi-particles of underlying spinons are orthogonal to physical electrons, giving rise to the ‘ARPES-dark’ state where the ARPES gap will be larger than the optical and thermal gap. (ii) The Ising insulator corresponding to ordered phase of the Ising variable is characterized by single-particle excitations whose dispersion is controlled by Ising-like temperature and field dependences. The temperature can be conveniently employed to drive a phase transition between these two insulating phases where Ising exponents become measurable by ARPES and cyclotron resonance. The rare earth monochalcogenide semiconductors where the magneto-resistance is anomalously large can be a candidate system for the Ising band insulator. We argue that the Ising and orthogonal insulating phases require strong enough ionic potential to survive the downward renormalization of the ionic potential caused by Hubbard U.

  15. Insulator-based DEP with impedance measurements for analyte detection

    Science.gov (United States)

    Davalos, Rafael V.; Simmons, Blake A.; Crocker, Robert W.; Cummings, Eric B.

    2010-03-16

    Disclosed herein are microfluidic devices for assaying at least one analyte specie in a sample comprising at least one analyte concentration area in a microchannel having insulating structures on or in at least one wall of the microchannel which provide a nonuniform electric field in the presence of an electric field provided by off-chip electrodes; and a pair of passivated sensing electrodes for impedance detection in a detection area. Also disclosed are assay methods and methods of making.

  16. Magnon-polaron transport in magnetic insulators

    OpenAIRE

    Flebus, Benedetta; Shen, Ka; Kikkawa, Takashi; Uchida, Ken-ichi; Qiu, Zhiyong; Saitoh, Eiji; Duine, Rembert A.; Bauer, Gerrit E. W.

    2017-01-01

    We theoretically study the effects of strong magnetoelastic coupling on the transport properties of magnetic insulators. We develop a Boltzmann transport theory for the mixed magnon-phonon modes (magnon polarons) and determine transport coefficients and spin diffusion length. Magnon-polaron formation causes anomalous features in the magnetic field and temperature dependence of the spin Seebeck effect when the disorder scattering in the magnetic and elastic subsystems is sufficiently different...

  17. Antifuse with a single silicon-rich silicon nitride insulating layer

    Science.gov (United States)

    Habermehl, Scott D.; Apodaca, Roger T.

    2013-01-22

    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.

  18. Design of insulator-based dielectrophoretic devices: Effect of insulator posts characteristics.

    Science.gov (United States)

    Saucedo-Espinosa, M A; Lapizco-Encinas, B H

    2015-11-27

    Insulator-based dielectrophoresis (iDEP) is a leading technique for the enrichment and manipulation of target bioparticles by exploiting physical and electrical properties of the particles and the suspending medium. Dielectrophoretic forces are produced by employing insulator posts that distort an otherwise uniform electric field. The optimal design for iDEP devices involves a careful balance between electrokinetics (EK) and dielectrophoresis (DEP) in the DEP-active area, where the design of the insulator posts is crucial for their performance. This contribution demonstrates the selection of a geometrical set of parameters that enhances particle capture and enrichment in an iDEP device. Numerical simulations, comprising an average trapping condition (TC) and the average lateral-to-longitudinal force ratio (FR) experienced by particles, were used to determine improved geometrical parameters (e.g., shape, length and width) and arrangement (e.g., lateral and longitudinal spacing) of the insulator posts. Experiments with polystyrene particles demonstrated the enhancement in particle enrichment, validating the employed key output parameters. The fabrication feasibility of the improved devices by a soft-lithographic process was also explored through numerical simulations and experiments. Optimal designs for this study were selected and their capture capacity was examined, demonstrating a decrease up to 84% in the electric potential necessary to generate a clear band of trapped particles. The findings from this study provide a systematic approach toward the design of high performance iDEP devices for their lab-on-a-chip integration. Copyright © 2015 Elsevier B.V. All rights reserved.

  19. Multilayer insulation thermal protection systems technology

    Science.gov (United States)

    Hyde, E. H.

    1971-01-01

    A summary is presented of the work performed by Marshall Space Flight Center (MSFC) and industry toward the development of flight-type multilayer insulation(MLI) systems. The MSFC MLI program is divided into three large categories: (1) the generation and compilation of MLI composite test data; (2) the analysis, design, and testing of heat flow through MLI applied to ducting, seams, electrical feedthroughs, structural supports, and the tank sidewall; and (3) the development, modification, and utilization of new testing procedures, tanks, and the test facilities. Numerous data have been generated, analyzed, and documented on different MLI composites.

  20. Tailoring tricolor structure of magnetic topological insulator for robust axion insulator.

    Science.gov (United States)

    Mogi, Masataka; Kawamura, Minoru; Tsukazaki, Atsushi; Yoshimi, Ryutaro; Takahashi, Kei S; Kawasaki, Masashi; Tokura, Yoshinori

    2017-10-01

    Exploration of novel electromagnetic phenomena is a subject of great interest in topological quantum materials. One of the unprecedented effects to be experimentally verified is the topological magnetoelectric (TME) effect originating from an unusual coupling of electric and magnetic fields in materials. A magnetic heterostructure of topological insulator (TI) hosts such exotic magnetoelectric coupling and can be expected to realize the TME effect as an axion insulator. We designed a magnetic TI with a tricolor structure where a nonmagnetic layer of (Bi, Sb)2Te3 is sandwiched by a soft ferromagnetic Cr-doped (Bi, Sb)2Te3 and a hard ferromagnetic V-doped (Bi, Sb)2Te3. Accompanied by the quantum anomalous Hall (QAH) effect, we observe zero Hall conductivity plateaus, which are a hallmark of the axion insulator state, in a wide range of magnetic fields between the coercive fields of Cr- and V-doped layers. The resistance of the axion insulator state reaches as high as 109 ohms, leading to a gigantic magnetoresistance ratio exceeding 10,000,000% upon the transition from the QAH state. The tricolor structure of the TI may not only be an ideal arena for the topologically distinct phenomena but can also provide magnetoresistive applications for advancing dissipation-less topological electronics.

  1. Spintronics Based on Topological Insulators

    Science.gov (United States)

    Fan, Yabin; Wang, Kang L.

    2016-10-01

    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. Manifold Insulation for Solar Collectors

    Science.gov (United States)

    1982-01-01

    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.

  3. High voltage variable diameter insulator

    Science.gov (United States)

    Vanecek, David L.; Pike, Chester D.

    1984-01-01

    A high voltage feedthrough assembly (10) having a tubular insulator (15) extending between the ground plane ring (16) and the high voltage ring (30). The insulator (15) is made of Pyrex and decreases in diameter from the ground plane ring (16) to the high voltage ring (30), producing equipotential lines almost perpendicular to the wall (27) of the insulator (15) to optimize the voltage-holding capability of the feedthrough assembly (10).

  4. Evaluation of Silicone Rubber Insulators used in High-Voltage Transmission Lines

    Science.gov (United States)

    Ul-Hamid, Anwar; Soufi, Khaled Y.; Al-Hamoudi, Ibrahim

    2008-04-01

    Three long-rod silicone rubber composite insulators used in 230 kV power transmission lines were evaluated for aging affects. The insulators were obtained from various outdoor desert locations within Saudi Arabia where they had been in service for 6 years. Surface degradation associated with the aging process was analyzed by using Scanning Electron Microscopy (SEM) coupled with Energy Dispersive X-ray Spectroscopy (EDS), Fourier Transform Infra-Red Spectroscopy (FTIR), and Electron Spectroscopy for Chemical Analysis (ESCA). Electrical performance of insulators was evaluated by Rapid Flashover Voltage Tests (RFVT) and Pollution Severity Measurement Tests. Depending on their locations of service, the samples exhibited various types of pollutants at their surfaces. The analysis indicated that the insulator material showed localized surface degradation while there was no evidence of micro-cracking. Furthermore, it was noted that the electrical performance of the insulators was not significantly affected by exposure during the in-service period.

  5. Low Permeability Polyimide Insulation Project

    Data.gov (United States)

    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...

  6. Analysis Code for High Gradient Dielectric Insulator Surface Breakdown

    Energy Technology Data Exchange (ETDEWEB)

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

    2010-05-30

    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.

  7. New Techniques to Evaluate the Incendiary Behavior of Insulators

    Science.gov (United States)

    Buhler, Charles; Calle, Carlos; Clements, Sid; Trigwell, Steve; Ritz, Mindy

    2008-01-01

    New techniques for evaluating the incendiary behavior of insulators is presented. The onset of incendive brush discharges in air is evaluated using standard spark probe techniques for the case simulating approaches of an electrically grounded sphere to a charged insulator in the presence of a flammable atmosphere. However, this standard technique is unsuitable for the case of brush discharges that may occur during the charging-separation process for two insulator materials. We present experimental techniques to evaluate this hazard in the presence of a flammable atmosphere which is ideally suited to measure the incendiary nature of micro-discharges upon separation, a measurement never before performed. Other measurement techniques unique to this study include; surface potential measurements of insulators before, during and after contact and separation, as well as methods to verify fieldmeter calibrations using a charge insulator surface opposed to standard high voltage plates. Key words: Kapton polyimide film, incendiary discharges, brush discharges, contact and frictional electrification, ignition hazards, insulators, contact angle, surface potential measurements.

  8. 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

    Energy Technology Data Exchange (ETDEWEB)

    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

    2009-07-01

    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)

  9. The CRRES IDM spacecraft experiment for insulator discharge pulses. [Internal Discharge Monitor

    Science.gov (United States)

    Frederickson, A. R.; Mullen, E. G.; Kerns, K. J.; Robinson, P. A.; Holeman, E. G.

    1993-01-01

    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.

  10. Passive Collecting of Solar Radiation Energy using Transparent Thermal Insulators, Energetic Efficiency of Transparent Thermal Insulators

    OpenAIRE

    Smajo Sulejmanovic; Suad Kunosic; Ema Hankic

    2014-01-01

    This paper explains passive collection of solar radiation energy using transparent thermal insulators. Transparent thermal insulators are transparent for sunlight, at the same time those are very good thermal insulators. Transparent thermal insulators can be placed instead of standard conventional thermal insulators and additionally transparent insulators can capture solar radiation, transform it into heat and save heat just as standard insulators. Using transparent insulators would lead to r...

  11. DNA topoisomerase II modulates insulator function in Drosophila.

    Directory of Open Access Journals (Sweden)

    Edward Ramos

    2011-01-01

    Full Text Available Insulators are DNA sequences thought to be important for the establishment and maintenance of cell-type specific nuclear architecture. In Drosophila there are several classes of insulators that appear to have unique roles in gene expression. The mechanisms involved in determining and regulating the specific roles of these insulator classes are not understood. Here we report that DNA Topoisomerase II modulates the activity of the Su(Hw insulator. Downregulation of Topo II by RNAi or mutations in the Top2 gene result in disruption of Su(Hw insulator function. This effect is mediated by the Mod(mdg42.2 protein, which is a unique component of the Su(Hw insulator complex. Co-immunoprecipitation and yeast two-hybrid experiments show that Topo II and Mod(mdg42.2 proteins directly interact. In addition, mutations in Top2 cause a slight decrease of Mod(mdg42.2 transcript but have a dramatic effect on Mod(mdg42.2 protein levels. In the presence of proteasome inhibitors, normal levels of Mod(mdg42.2 protein and its binding to polytene chromosomes are restored. Thus, Topo II is required to prevent Mod(mdg42.2 degradation and, consequently, to stabilize Su(Hw insulator-mediated chromatin organization.

  12. DNA Topoisomerase II Modulates Insulator Function in Drosophila

    Science.gov (United States)

    Ramos, Edward; Torre, Eduardo A.; Bushey, Ashley M.; Gurudatta, B. V.; Corces, Victor G.

    2011-01-01

    Insulators are DNA sequences thought to be important for the establishment and maintenance of cell-type specific nuclear architecture. In Drosophila there are several classes of insulators that appear to have unique roles in gene expression. The mechanisms involved in determining and regulating the specific roles of these insulator classes are not understood. Here we report that DNA Topoisomerase II modulates the activity of the Su(Hw) insulator. Downregulation of Topo II by RNAi or mutations in the Top2 gene result in disruption of Su(Hw) insulator function. This effect is mediated by the Mod(mdg4)2.2 protein, which is a unique component of the Su(Hw) insulator complex. Co-immunoprecipitation and yeast two-hybrid experiments show that Topo II and Mod(mdg4)2.2 proteins directly interact. In addition, mutations in Top2 cause a slight decrease of Mod(mdg4)2.2 transcript but have a dramatic effect on Mod(mdg4)2.2 protein levels. In the presence of proteasome inhibitors, normal levels of Mod(mdg4)2.2 protein and its binding to polytene chromosomes are restored. Thus, Topo II is required to prevent Mod(mdg4)2.2 degradation and, consequently, to stabilize Su(Hw) insulator-mediated chromatin organization. PMID:21304601

  13. Building ceramics with improved thermal insulation parameters

    Directory of Open Access Journals (Sweden)

    Rzepa Karol

    2016-01-01

    Full Text Available One of the most important performance characteristics of masonry units is their high thermal insulation. There are many different ways to improve this parameter, however the most popular methods in case of ceramic masonry units are: addition of pore-creating raw materials and application of proper hole pattern. This study was an attempt to improve thermal insulation of ceramics by applying thermal insulation additives. Perlite dust created as a subgrain from expansion of perlite rock was used. Perlite subgrain is not very popular among consumers, that’s why it’s subjected to granulation to obtain coarse grain. The authors presented concept of direct application of perlite dust for the production of building ceramics with improved thermal insulation. Fineness of this additive is asset for molding of ceramic materials from plastic masses. Based on the results it was found that about 70% perlite by volume can be added to obtain material with a coefficient of heat conductivity of 0,37 W/mK. Higher content of this additive in ceramic mass causes deterioration of its rheological properties. Mass loses its plasticity, it tears up and formed green bodies are susceptible to deformation. During sintering perlite takes an active part in compaction process. Higher sintering dynamics is caused by: high content of alkali oxides in perlite and glass nature of perlite. Alkali oxides generate creation of liquid phase which intensifies mass compaction processes. Active role of perlite in sintering process causes good connection of its grains with clay groundwork which is important factor for mechanical parameters of ceramic materials. It was also noted that addition of perlite above 40% by volume of mass effectively neutralized negative effect of efflorescence in ceramic materials.

  14. Insulators: estructura y funciones

    OpenAIRE

    Fresán Salvo, Ujué

    2016-01-01

    [spa] Los insulators son complejos de DNA y proteínas, cuya función no solo consiste en impedir la comunicación enhancer-promotor y/o bloquear la expansión del silenciamiento de la heterocromatina como clásicamente se habían descrito. Median interacciones intra e intercromosomales, cuyo objetivo fmal es la organización del genoma en diferentes dominios, regulando por consiguiente las funciones del DNA. Uno de los objetivos de esta tesis fue la búsqueda de nuevas funciones de proteínas insulat...

  15. Measurement of the Relative Free Radical Content of Insulating Oils of Petroleum Origin

    Directory of Open Access Journals (Sweden)

    Issouf Fofana

    2015-07-01

    Full Text Available Oil/paper insulation degradation in transformers involves chemical and physical changes in the materials. Some of the chemical reactions involve very reactive intermediates called free radicals. Free radicals play a major role in a wide variety of ageing processes. The detection of these reactive species in oil may, in principle, provide useful information for monitoring oil degradation. This manuscript details a laboratory technique, which determines the relative content of free radicals in insulating oils of petroleum origin by a spectrophotometric method. Free radicals may be formed in oils under operating or test conditions. The procedure enables the determination of the relative concentration of free radicals, which can act as the precursors of decay products such as charge carriers, oxidized molecules, as well as polymerization products. The technique involves using a reactive free radical reagent, 2,2-diphenyl-1-picrylhydrazyl (DPPH, added to oil to assess free radical concentration. This method is applicable to new, reclaimed, or used oils as well as naturally or artificially oxidized oil (the cause of aging can be chemical, physical, or electrical. In this contribution, free radicals were assessed following electrical discharge application in oil.

  16. The influence of insulation materials on corrosion under insulation

    Energy Technology Data Exchange (ETDEWEB)

    Williams, J.; Evans, O. [Aspen Aerogels Inc., Northborough, MA (United States)

    2010-07-01

    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. Electrical Injuries

    Science.gov (United States)

    ... it can pass through your body and cause injuries. These electrical injuries can be external or internal. You may have one or both types. External injuries are skin burns. Internal injuries include damage to ...

  18. Very low and broad threshold voltage fluctuation caused by ion implantation to silicon-on-insulator triple-gate fin-type field effect transistor using three-dimensional process and device simulations

    Science.gov (United States)

    Tsutsumi, Toshiyuki

    2017-06-01

    The threshold voltage (V th) fluctuation induced by the ion implantation to the source and drain extensions (SDE) of a silicon-on-insulator (SOI) triple-gate (tri-gate) fin-type field-effect transistor (FinFET) was analyzed for the first time with the use of realistic positional information of discretely doped ions by both three-dimensional (3D) process and device simulations. Interestingly, it was found that the V th fluctuation induced by SDE ion implantation has a very low and broad distribution on the low-V th side even in the case of a robust device structure such as SOI tri-gate FinFET. Furthermore, for the first time, it was quantitatively demonstrated using a proposed cluster percolation model that the origin of the very low and broad V th fluctuation is the conductive percolation among unintentionally doped ions in the channel region of the device. These results would contribute to the realization of robust transistors.

  19. Wall Insulation; BTS Technology Fact Sheet

    Energy Technology Data Exchange (ETDEWEB)

    Southface Energy Institute; Tromly, K.

    2000-11-07

    Properly sealed, moisture-protected, and insulated walls help increase comfort, reduce noise, and save on energy costs. This fact sheet addresses these topics plus advanced framing techniques, insulation types, wall sheathings, and steps for effective wall construction and insulation.

  20. Indigenous Manufacture and Characterization of Electrical Porcelain ...

    African Journals Online (AJOL)

    To this end, an electrical porcelain insulator was manufactured from locally available raw materials and characterized. The study ... considered. These results when compared with those of the commercial variety show that the locally manufactured sample satisfies the stringent requirements of a good insulating material.

  1. Transpiration cooled electrodes and insulators for MHD generators

    Science.gov (United States)

    Hoover, Jr., Delmer Q.

    1981-01-01

    Systems for cooling the inner duct walls in a magnetohydrodynamic (MHD) generator. The inner face components, adjacent the plasma, are formed of a porous material known as a transpiration material. Selected cooling gases are transpired through the duct walls, including electrically insulating and electrode segments, and into the plasma. A wide variety of structural materials and coolant gases at selected temperatures and pressures can be utilized and the gases can be drawn from the generation system compressor, the surrounding environment, and combustion and seed treatment products otherwise discharged, among many other sources. The conduits conducting the cooling gas are electrically insulated through low pressure bushings and connectors so as to electrically isolate the generator duct from the ground.

  2. Preparation and characterization of EPDM-silica nano/micro composites for high voltage insulation applications

    Directory of Open Access Journals (Sweden)

    Ali Muhammad

    2015-03-01

    Full Text Available The rising market for substitute materials in high voltage insulation components is stimulated largely by the need to reduce overall costs. In this respect, polymer insulators offer significant advantages over old traditional materials. In the present research, efforts have been made to quantify the effect of silica (having different particle size nano, micro and hybrid loading on the mechanical and thermal behaviors of Ethylene-Propylene-Diene Monomer (EPDM based high voltage electrical insulations. The fabricated composites were subjected to mechanical, thermal and electrical properties measurements. The results of dielectric strength, surface and volume resistivities showed that all composites had insulator properties, while their mechanical and thermal properties improved considerably. EPDM was compounded with different types of silica in a two roll mill using sulphur cure system. The outcome achieved from the comparative study revealed that the EPDM nanocomposites had enhanced mechanical, thermal and electrical properties even at 5 % loadings.

  3. Quantum spin liquids and the metal-insulator transition in doped semiconductors.

    Science.gov (United States)

    Potter, Andrew C; Barkeshli, Maissam; McGreevy, John; Senthil, T

    2012-08-17

    We describe a new possible route to the metal-insulator transition in doped semiconductors such as Si:P or Si:B. We explore the possibility that the loss of metallic transport occurs through Mott localization of electrons into a quantum spin liquid state with diffusive charge neutral "spinon" excitations. Such a quantum spin liquid state can appear as an intermediate phase between the metal and the Anderson-Mott insulator. An immediate testable consequence is the presence of metallic thermal conductivity at low temperature in the electrical insulator near the metal-insulator transition. Further, we show that though the transition is second order, the zero temperature residual electrical conductivity will jump as the transition is approached from the metallic side. However, the electrical conductivity will have a nonmonotonic temperature dependence that may complicate the extrapolation to zero temperature. Signatures in other experiments and some comparisons with existing data are made.

  4. Exploring Insulation with Ice Hands

    Science.gov (United States)

    Taylor, Neil; Taylor, Subhashni; Littledyke, Michael

    2017-01-01

    Students often hold misconceptions about insulation, largely because they put on clothes to keep themselves warm--at least in winter in the cooler regions of Australia. The following activity is designed to identify students' misconceptions about insulation and provide an engaging, evidence-based activity to help address these misconceptions using…

  5. Plastic Materials for Insulating Applications.

    Science.gov (United States)

    Wang, S. F.; Grossman, S. J.

    1987-01-01

    Discusses the production and use of polymer materials as thermal insulators. Lists several materials that provide varying degrees of insulation. Describes the production of polymer foam and focuses on the major applications of polystyrene foam, polyurethane foam, and polyisocyanurate foam. (TW)

  6. Structural and Electrical Characteristics of Metal-Ferroelectric Pb1.1(Zr0.40Ti0.60O3-Insulator (ZnO-Silicon Capacitors for Nonvolatile Applications

    Directory of Open Access Journals (Sweden)

    S. R. Krishnamoorthi

    2013-01-01

    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.

  7. Optimum Scheme for Insulation System in HV Generator Based on Electromagnetic Analysis

    Directory of Open Access Journals (Sweden)

    A. Gholami

    2011-06-01

    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.

  8. MOSFET Electric-Charge Sensor

    Science.gov (United States)

    Robinson, Paul A., Jr.

    1988-01-01

    Charged-particle probe compact and consumes little power. Proposed modification enables metal oxide/semiconductor field-effect transistor (MOSFET) to act as detector of static electric charges or energetic charged particles. Thickened gate insulation acts as control structure. During measurements metal gate allowed to "float" to potential of charge accumulated in insulation. Stack of modified MOSFET'S constitutes detector of energetic charged particles. Each gate "floats" to potential induced by charged-particle beam penetrating its layer.

  9. Hybrid Multifoil Aerogel Thermal Insulation

    Science.gov (United States)

    Sakamoto, Jeffrey; Paik, Jong-Ah; Jones, Steven; Nesmith, Bill

    2008-01-01

    This innovation blends the merits of multifoil insulation (MFI) with aerogel-based insulation to develop a highly versatile, ultra-low thermally conductive material called hybrid multifoil aerogel thermal insulation (HyMATI). The density of the opacified aerogel is 240 mg/cm3 and has thermal conductivity in the 20 mW/mK range in high vacuum and 25 mW/mK in 1 atmosphere of gas (such as argon) up to 800 C. It is stable up to 1,000 C. This is equal to commercially available high-temperature thermal insulation. The thermal conductivity of the aerogel is 36 percent lower compared to several commercially available insulations when tested in 1 atmosphere of argon gas up to 800 C.

  10. Ageing and Partial Discharge Patterns in Oil-Impregnated Paper and Pressboard Insulation at High Temperature

    OpenAIRE

    R. H. Khawaja; T. R. Blackburn; M. Rehan Arif

    2009-01-01

    The power transformer is the most expensive, indispensable and arguably the most important equipment item in a power system Insulation failure in transformers can cause long term interruption to supply and loss of revenue and the condition assessment of the insulation is thus an important maintenance procedure. Oil-impregnated transformer insulation consists of mainly organic materials including mineral oil and cellulose-base paper and pressboard. The operating life of cellulose-based insulat...

  11. Analysis of the Influence of Construction Insulation Systems on Public Safety in China

    OpenAIRE

    Guowei Zhang; Guoqing Zhu; Guoxiang Zhao

    2016-01-01

    With the Government of China?s proposed Energy Efficiency Regulations (GB40411-2007), the implementation of external insulation systems will be mandatory in China. The frequent external insulation system fires cause huge numbers of casualties and extensive property damage and have rapidly become a new hot issue in construction evacuation safety in China. This study attempts to reconstruct an actual fire scene and propose a quantitative risk assessment method for upward insulation system fires...

  12. HARMONIC ANALYSIS OF LEAKAGE CURRENT OF SILICON RUBBER INSULATORS IN CLEAN-FOG AND SALT-FOG

    OpenAIRE

    Rostaghi-Chalaki, Mojtaba; Shayegani-Akmal, A,; Mohseni, H

    2013-01-01

    International audience; Environmental and electrical stresses have deterioration effects on Silicon Rubber (SIR) insulators. In coastal areas due to high amount of salt, humidity and dust suspended in the air, the deterioration process is intensive. In this paper, based on IEC 60507 the leakage current (LC) of 20kV SIR insulators has been investigated in clean-fog and salt-fog with and without artificial pollution. Tests have been executed with six similar SIR insulators. A pair of polluted a...

  13. Metallization of electronic insulators

    Science.gov (United States)

    Gottesfeld, Shimshon; Uribe, Francisco A.

    1994-01-01

    An electroplated element is formed to include an insulating substrate, a conducting polymer polymerized in situ on the substrate, and a metal layer deposited on the conducting polymer. In one application a circuit board is formed by polymerizing pyrrole on an epoxy-fiberglass substrate in a single step process and then electrodepositing a metal over the resulting polypyrrole polymer. No chemical deposition of the metal is required prior to electroplating and the resulting layer of substrate-polymer-metal has excellent adhesion characteristics. The metal deposition is surprisingly smooth and uniform over the relatively high resistance film of polypyrrole. A continuous manufacturing process is obtained by filtering the solution between successive substrates to remove polymer formed in the solution, by maintaining the solution oxidizing potential within selected limits, and by adding a strong oxidant, such as KMnO.sub.4 at periodic intervals to maintain a low sheet resistivity in the resulting conducting polymer film.

  14. SEALED INSULATOR BUSHING

    Science.gov (United States)

    Carmichael, H.

    1952-11-11

    The manufacture of electrode insulators that are mechanically strong, shock-proof, vacuum tight, and are capable of withstanding gas pressures of many atmospheres under intense neutron bombardment, such as may be needed in an ionization chamber, is described. The ansulator comprises a bolt within a quartz tube, surrounded by a bushing held in place by two quartz rings, and tightened to a pressure of 1,000 pounds per square inch by a nut and washer. Quartz is the superior material to meet these conditions, however, to withstand this pressure the quartz must be fire polished, lapped to form smooth and parallel surfaces, and again fire polished to form an extremely smooth and fracture resistant mating surface.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2017-06-15

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

  16. Evaluation of the Fretting Resistance of the High Voltage Insulation on the ITER Magnet Feeder Busbars

    Science.gov (United States)

    Clayton, N.; Crouchen, M.; Evans, D.; Gung, C.-Y.; Su, M.; Devred, A.; Piccin, R.

    2017-12-01

    The high voltage (HV) insulation on the ITER magnet feeder superconducting busbars and current leads will be prepared from S-glass fabric, pre-impregnated with an epoxy resin, which is interleaved with polyimide film and wrapped onto the components and cured during feeder manufacture. The insulation architecture consists of nine half-lapped layers of glass/Kapton, which is then enveloped in a ground-screen, and two further half-lapped layers of glass pre-preg for mechanical protection. The integrity of the HV insulation is critical in order to inhibit electrical arcs within the feeders. The insulation over the entire length of the HV components (bus bar, current leads and joints) must provide a level of voltage isolation of 30 kV. In operation, the insulation on ITER busbars will be subjected to high mechanical loads, arising from Lorentz forces, and in addition will be subjected to fretting erosion against stainless steel clamps, as the pulsed nature of some magnets results in longitudinal movement of the busbar. This work was aimed at assessing the wear on, and the changes in, the electrical properties of the insulation when subjected to typical ITER operating conditions. High voltage tests demonstrated that the electrical isolation of the insulation was intact after the fretting test.

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

    Directory of Open Access Journals (Sweden)

    J. W. Zhang

    2017-10-01

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

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

    Science.gov (United States)

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

    2017-10-01

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

  19. Homeowners' demand for home insulation

    Energy Technology Data Exchange (ETDEWEB)

    None

    1978-04-01

    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.

  20. Topological crystalline insulator SnTe nanoribbons

    Science.gov (United States)

    Dahal, Bishnu R.; Dulal, Rajendra P.; Pegg, Ian L.; Philip, John

    2017-03-01

    Topological crystalline insulators are systems in which a band inversion that is protected by crystalline mirror symmetry gives rise to nontrivial topological surface states. SnTe is a topological crystalline insulator. It exhibits p-type conductivity due to Sn vacancies and Te antisites, which leads to high carrier density in the bulk. Thus growth of high quality SnTe is a prerequisite for understanding the topological crystalline insulating behavior. We have grown SnTe nanoribbons using a solution method. The width of the SnTe ribbons varies from 500 nm to 2 μm. They exhibit rock salt crystal structure with a lattice parameter of 6.32 Å. The solution method that we have adapted uses low temperature, so the Sn vacancies can be controlled. The solution grown SnTe nanoribbons exhibit strong semiconducting behavior with an activation energy of 240 meV. This activation energy matches with the calculated band gap for SnTe with a lattice parameter of 6.32 Å, which is higher than that reported for bulk SnTe. The higher activation energy makes the thermal excitation of bulk charges very difficult on the surface. As a result, the topological surfaces will be free from the disturbance caused by the thermal excitations

  1. Voltage surges and insulation coordination. Translations from the papers of the International Conference on Large-Scale Power Systems, SIGRE-78. Perenapriazheniia i koordinatsiia izoliatsii. Perevody Dokladov Mezhdunarodoni konferentsii po bolshim elektricheskym sistemam, SIGRE-78

    Energy Technology Data Exchange (ETDEWEB)

    1982-01-01

    This volume contains translations of the papers given at the SIGRE Session in 1978 devoted to the following problem: the operational reliability of linear and substation insulation for high-voltage equipment in pollution and high-salinity conditions; voltage surges and voltage surge protection using overvoltage limiters which employ zinc oxide resistors, coordinating the electrical insulation of unitized distribution units under the influence of waves with a steep front, and coordinating the electrical insulation of high-voltage dc electrical equipment.

  2. A deterministic model for the growth of non-conducting electrical tree structures

    CERN Document Server

    Dodd, S J

    2003-01-01

    Electrical treeing is of interest to the electrical generation, transmission and distribution industries as it is one of the causes of insulation failure in electrical machines, switchgear and transformer bushings. In this paper a deterministic electrical tree growth model is described. The model is based on electrostatics and local electron avalanches to model partial discharge activity within the growing tree structure. Damage to the resin surrounding the tree structure is dependent on the local electrostatic energy dissipation by partial discharges within the tree structure and weighted by the magnitudes of the local electric fields in the resin surrounding the tree structure. The model is successful in simulating the formation of branched structures without the need of a random variable, a requirement of previous stochastic models. Instability in the spatial development of partial discharges within the tree structure takes the role of the stochastic element as used in previous models to produce branched t...

  3. Physical processes in high field insulating liquid conduction

    Science.gov (United States)

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

    2017-10-01

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

  4. Effect of Enhanced Air Temperature (extreme heat, and Load of Non-Linear Against the Use of Electric Power

    Directory of Open Access Journals (Sweden)

    I Ketut Wijaya

    2015-12-01

    Full Text Available Usage Electric power is very easy to do, because the infrastructure for connecting  already available and widely sold. Consumption electric power is not accompanied by the ability to recognize electric power. The average increase of electricity power in Bali in extreme weather reaches 10% in years 2014, so that Bali suffered power shortages and PLN as the manager of electric power to perform scheduling on of electric power usage. Scheduling is done because many people use electric power as the load  of fan and Air Conditioner exceeding the previous time. Load of fan, air conditioning, and computers including non-linear loads which can add heat on the conductor of electricity. Non-linear load and hot weather can lead to heat on conductor so  insulation damaged  and cause electrical short circuit. Data of electric power obtained through questionnaires, surveys, measurement and retrieve data from various parties. Fires that occurred in 2014, namely 109 events, 44 is  event caused by an electric short circuit (approximately 40%. Decrease power factors can cause losses of electricity and hot. Heat can cause and adds heat on the  conductor electric. The analysis showed  understanding electric power of the average  is 27,700 with value between 20 to 40. So an understanding of the electrical power away from the understand so that many errors because of the act own. Installation tool ELCB very necessary but very necessary provide counseling   of electricity to the community.

  5. Insulated conductor temperature limited heater for subsurface heating coupled in a three-phase WYE configuration

    Energy Technology Data Exchange (ETDEWEB)

    Vinegar, Harold J. (Bellaire, TX); Sandberg, Chester Ledlie (Palo Alto, CA)

    2010-11-09

    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.

  6. Observation of a macroscopic topological insulator phase in an assembly of coupled topological insulator nanocrystals

    Science.gov (United States)

    Sen, Diptiman; Banerjee, Abhishek; Deb, Oindrila; Majhi, Kunjalata; Ganesan, R.; Kumar, P. S. Anil

    We study an assembly of tunnel coupled topological insulator (TI) nanocrystals. We demonstrate experimentally that a macroscopic topological insulator phase can emerge in this system. Electrical transport measurements on thin films of Bi2Se3 nanocrystals reveal the presence of decoupled top and bottom topological surface states above a certain film thickness. The surface state penetration depth is found to be unusually large, 30nm at 2K, and decreases with increasing temperature. For samples with low film thickness, we observe deviations of the surface state Berry phase from π due to hybridization of opposite surface states. This weakens the effective spin-orbit coupling field to as low as 30T at 2K. Remarkably, the topological insulating behavior becomes more pronounced with increasing temperature. Our work exhibits a model TI that is distinct from bulk/single crystal TIs and also displays phenomena that are expected, but normally not accessible in the latter systems. K.M. thanks CSIR, India for financial support. D.S. thanks DST, India for support under Grant No. SR/S2/JCB-44/2010. P.S.A.K. acknowledges Nanomission, DST, Govt. of India for support.

  7. Electrical control of exchange bias via oxygen migration across CoO-ZnO nanocomposite barrier

    Science.gov (United States)

    Li, Q.; Yan, S. S.; Xu, J.; Li, S. D.; Zhao, G. X.; Long, Y. Z.; Shen, T. T.; Zhang, K.; Zhang, J.

    2016-12-01

    We proposed a nanocomposite barrier CoO-ZnO for magnetism manipulation in Co/CoO-ZnO/Ag heterojunctions. Both electrical control of magnetism and resistive switching were realized in this junction. An electrical tunable exchange bias of CoO1-v (v denotes O vacancies) on Co films was realized using voltages below 1 volt. The magnetism modulation associated with resistive switching can be attributed to the oxygen ions migration between the insulating CoO1-v layer and the semiconductive ZnO1-v layer, which can cause both ferromagnetic phase and resistance switching of CoO1-v layer.

  8. Measure Guideline: Basement Insulation Basics

    Energy Technology Data Exchange (ETDEWEB)

    Aldrich, R.; Mantha, P.; Puttagunta, S.

    2012-10-01

    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.

  9. Evaluation of thermal insulation materials

    Science.gov (United States)

    Wilbers, O. J.; Conti, J. C.; Mcgee, J. V.; Mcpherson, J. I.

    1973-01-01

    Data was obtained on silicone-bonded fiberglass, isocyanurate foam, and two dozen other insulators. Materials were selected to withstand heat sterilization, outer space, and the Martian atmosphere. Significant environmental parameters were vibration, landing shock, and launch venting.

  10. Insulators to Improve the Safety of Retroviral Vectors for HIV Gene Therapy

    Science.gov (United States)

    Browning, Diana L.; Trobridge, Grant D.

    2016-01-01

    Retroviral vector gene therapy is a promising approach to treating HIV-1. However, integrated vectors are mutagens with the potential to dysregulate nearby genes and cause severe adverse side effects. Leukemia has already been a documented severe adverse event in gene therapy clinical trials for the treatment of primary immunodeficiencies. These side effects will need to be reduced or avoided if retroviral vectors are to be used clinically for HIV-1 treatment. The addition of chromatin insulators to retroviral vectors is a potential strategy for reducing adverse side effects. Insulators have already been effectively used in retroviral vectors to reduce genotoxicity in pre-clinical studies. Here, we will review how insulators function, genotoxicity in gene therapy clinical trials, the design of insulated retroviral vectors, promising results from insulated retroviral vector studies, and considerations for the development of insulated retroviral treatment vectors for HIV-1 gene therapy. PMID:28424756

  11. Jahn-Teller and Non-Jahn-Teller Systems Involving CuF64- Units: Role of the Internal Electric Field in Ba2ZnF6:Cu2+ and Other Insulating Systems

    DEFF Research Database (Denmark)

    Aramburu, J. A.; Garcia-Fernandez, P.; García Lastra, Juan Maria

    2017-01-01

    it is pointed out that a quasi-JT situation can however happen for a d9 ion in a cubic lattice under a strain of ∼10-3 in agreement with experimental data. The present results stress the key role played by the internal electric fields for a quantitative understanding of compounds with transition metal cations...... transitions for CuF64- units formed in Cu2+-doped the tetragonal Ba2ZnF6 host lattice. While the experimental d-d transitions cannot be reproduced through the isolated CuF64- unit at the equilibrium geometry, a reasonable agreement is reached adding in the calculation the internal electric field, ER...

  12. Outdoor leakage current monitoring of silicone composite insulators in coastal service conditions

    Energy Technology Data Exchange (ETDEWEB)

    Vlastos, A.E. [Chalmers Univ. of Technology, Gothenburg (Sweden); Orbeck, T. [Sediver Inc., York, SC (United States)

    1996-04-01

    The behavior of the polymeric insulators under salt-storm conditions is crucial for their design. In this paper the leakage currents monitored on silicone composite insulators during two severe salt-storms on the Swedish West Coast are analyzed. The results show that reduction of the leakage distance on silicone rubber units causes considerable dry-band arc activity.

  13. Variable pressure thermal insulating jacket

    Science.gov (United States)

    Nelson, Paul A.; Malecha, Richard F.; Chilenskas, Albert A.

    1994-01-01

    A device for controlled insulation of a thermal device. The device includes a thermal jacket with a closed volume able to be evacuated to form an insulating jacket around the thermal source. A getter material is in communcation with the closed volume of the thermal jacket. The getter material can absorb and desorb a control gas to control gas pressure in the volume of the thermal jacket to control thermal conductivity in the thermal jacket.

  14. Advanced silicon on insulator technology

    Science.gov (United States)

    Godbey, D.; Hughes, H.; Kub, F.

    1991-01-01

    Undoped, thin-layer silicon-on-insulator was fabricated using wafer bonding and selective etching techniques employing a molecular beam epitaxy (MBE) grown Si0.7Ge0.3 layer as an etch stop. Defect free, undoped 200-350 nm silicon layers over silicon dioxide are routinely fabricated using this procedure. A new selective silicon-germanium etch was developed that significantly improves the ease of fabrication of the bond and etch back silicon insulator (BESOI) material.

  15. Cable Insulation Scheme to Improve Heat Transfer to Superfluid Helium in Nb-Ti Accelerator Magnets

    CERN Document Server

    La China, M

    2008-01-01

    In superconducting magnets operating at high heat loads as the ones for interaction region of particle colliders or for fast cycling synchrotrons, the limited heat transfer capability of state-of-the-art electrical insulation may constitute a heavy limitation to performance. In the LHC main magnets, Nb-Ti epoxy-free insulation, composed of polyimide tapes, has proved to be permeable to superfluid helium, however the heat flux is rather limited. After a review of the standard insulation scheme for Nb-Ti and of the associated heat transfer mechanisms, we show the existence of a large margin available to improve insulation permeability.We propose a possible way to profit of such a margin in order to increase significantly the maximum heat flux drainable from an all polyimide insulated Nb-Ti coil, as it is used in modern accelerator magnets.

  16. Spintronics and spincaloritronics in topological insulators

    OpenAIRE

    Yokoyama, Takehito; Murakami, Shuichi

    2013-01-01

    We study spintronics and spincaloritronics in topological insulators. We show spintronics effects in 2D topological insulator junctions and 3D topological insulators coupled to ferromagnets. We also investigate spin polarization on the surface of a topological insulator induced by a circularly polarized light and refraction at the junction between two topological insulators. As for spincaloritronics effects, we show transverse magnetic heat transport and thermoelectric transport in topologica...

  17. Anomalous thermoelectric properties of a Floquet topological insulator with spin momentum non-orthogonality

    Science.gov (United States)

    Saha, Madhumita; Chowdhury, Debashree

    2017-11-01

    The spin momentum non-orthogonality in 3D topological insulators leads to modification of the spin texture and brings in an out-of-plane spin polarization component. Apart from the spin texture, the anomalous thermoelectric properties of these materials are worth studying. In this paper, we have pointed out that the off resonant light used to irradiate the surface states, induces a gap, which becomes momentum dependent due to the presence of non-orthogonal terms in the Hamiltonian. Importantly, to maintain the off resonant condition of light, the momentum value should satisfy a bound. Furthermore, the momentum dependent gap causes a topological transition at a higher value of momentum, which is important to analyse the unusual double peak structure of the Nernst and electrical conductivities.

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

    Science.gov (United States)

    Loh, Yen Lee; Karki, Pragalv

    2017-10-25

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

  19. Thermally Enhanced Cable Insulation for the Nb-Ti High Luminosity LHC Inner Triplet Model

    CERN Document Server

    Granieri, P P; Richter, D; Tommasini, D

    2012-01-01

    A new concept of polyimide electrical insulation for superconducting cables of accelerator magnets was developed in the last years. Its enhanced He II permeability allows a significant improvement of the heat extraction from the coil. This cable insulation concept is used for the quadrupole magnet prototype for the insertion region of the High Luminosity - Large Hadron Collider project. It aims at pushing the limits of the Nb Ti technology to withstand high heat deposition. Cable samples wrapped with the new insulation scheme were characterized from the thermal standpoint, as well as from the electrical and mechanical ones. In particular, heat transfer measurements from insulated cables towards the helium cooling bath were performed in a coil-like configuration. Various wrapping schemes were tested in different mechanical conditions, and a model was developed to explain the experimental results. The paper summarizes the main results of all these investigations.

  20. Strain induced novel quantum magnetotransport properties of topological insulators

    Energy Technology Data Exchange (ETDEWEB)

    Ma, Ning, E-mail: maning@stu.xjtu.edu.cn [Department of Physics, Taiyuan University of Technology, Taiyuan 030024 (China); Department of Applied Physics, MOE Key Laboratory for Nonequilibrium Synthesis and Modulation of Condensed Matter, Xi’an Jiaotong University, Xi’an 710049 (China); Zhang, Shengli, E-mail: zhangsl@mail.xjtu.edu.cn [Department of Applied Physics, MOE Key Laboratory for Nonequilibrium Synthesis and Modulation of Condensed Matter, Xi’an Jiaotong University, Xi’an 710049 (China); Liu, Daqing, E-mail: liudq@cczu.edu.cn [School of Mathematics and Physics, Changzhou University, Changzhou 213164 (China)

    2016-12-15

    Recent theoretical and experimental researches have revealed that the strained bulk HgTe can be regarded as a three-dimensional topological insulator (TI). Motivated by this, we explore the strain effects on the transport properties of the HgTe surface states, which are modulated by a weak 1D in-plane electrostatic periodic potential in the presence of a perpendicular magnetic field. We analytically derive the zero frequency (dc) diffusion conductivity for the case of quasielastic scattering in the Kubo formalism, and find that, in strong magnetic field regime, the Shubnikov–de Haas oscillations are superimposed on top of the Weiss oscillations due to the electric modulation for null and finite strain. Furthermore, the strain is shown to remove the degeneracy in inversion symmetric Dirac cones on the top and bottom surfaces. This accordingly gives rise to the splitting and mixture of Landau levels, and the asymmetric spectrum of the dc conductivity. These phenomena, not known in a conventional 2D electron gas and even in a strainless TI and graphene, are a consequence of the anomalous spectrum of surface states in a fully stained TI. These results should be valuable for electronic and spintronic applications of TIs, and thus we fully expect to see them in the further experiment. - Highlights: • The strain removes the degeneracy in inversion symmetric Dirac cones. • The strain gives rise to the splitting and mixture of the Landau levels. • The strain leads to the asymmetric spectrum of the dc conductivity. • Shubnikov de Haas oscillations are shown to be superimposed on Weiss oscillations. • Interplay between strain and electric field causes different occupancy of TI states.