WorldWideScience

Sample records for providing turn-to-turn insulation

  1. An interim report on the materials and selection criteria analysis for the Compact Ignition Tokamak Toroidal Field Coil Turn-to-Turn Insulation System

    International Nuclear Information System (INIS)

    Campbell, V.W.; Dooley, J.B.; Hubrig, J.G.; Janke, C.J.; McManamy, T.J.; Welch, D.E.

    1990-01-01

    Design criteria for the Compact Ignition Tokamak, Toroidal-Field (TF) Coil, Turn-to-Turn Insulation System require an insulation sheet and bonding system that will survive cryogenic cycling in a radiation environment and maintain structural integrity during exposure to the significant compressive and shear loads associated with each operating cycle. For thermosetting resin systems, a complex interactive dependency exists between optimum peak value, in-service property performance capabilities of candidate generic materials; key handling and processing parameters required to achieve their optimum in-service property performance as an insulation system; and suitability of their handling and processing parameters as a function of design configuration and assembly methodology. This dependency is assessed in a weighted study matrix in which two principal programmatic approaches for the development of the TF Coil Subassembly Insulation System have been identified. From this matrix study, two viable approaches to the fabrication of the insulation sheet were identified: use of a press-formed sheet bonded in place with epoxy for mechanical bonding and tolerance take-up and formation of the insulation sheet by placement of dry cloth and subsequent vacuum pressure impregnation. Laboratory testing was conducted to screen a number of combinations of resins and hardeners on a generic basis. These combinations were chosen for their performance in similar applications. Specimens were tested to screen viscosity, thermal-shock tolerance, and cryogenic tolerance. Cryogenic shock and cryogenic temperature proved to be extremely lethal to many combinations of resin, hardener, and cure. Two combinations survived: a heavily flexibilized bisphenol A resin with a flexibilized amine hardener and a bisphenol A resin with cycloaliphatic amine hardener. 7 refs., 12 figs., 6 tabs

  2. An interim report on the materials and selection criteria analysis for the Compact Ignition Tokamak toroidal field coil turn-to-turn insulation system

    International Nuclear Information System (INIS)

    Campbell, V.W.; Dooley, J.B.; Hubrig, J.G.; Janke, C.J.; McManamy, T.J.; Welch, D.E.

    1990-01-01

    This document contains photographs showing the results of laboratory testing of the combinations of epoxy resins, hardeners, and cures undertaken as part of the Compact Ignition Tokamak Insulation Screening Program. Cryogenic shock and soak to equilibrium proved to be the most demanding condition for these materials. The degree of damage to the basic materials when a poor candidate is selected is shown to be quite dramatic. 34 figs

  3. Electrical Machines: Turn-to-Turn Capacitance in Formed Windings with Rectangular Cross-Section Wire

    NARCIS (Netherlands)

    Djukic, Nenad; Encica, L.; Paulides, Johan

    2015-01-01

    Calculation of turn-to-turn capacitance (Ctt) in electrical machines (EMs) with formed windings with rectangular cross-section wire is presented. Three calculation methods are used for the calculation of Ctt in case of rectangular conductors – finite element (FE) method and two previously published

  4. Study on Turn-to-turn Short Circuit On一line Monitoring System for Dry一type Ai r一core Reactor

    Directory of Open Access Journals (Sweden)

    GAO Zi-wei

    2017-04-01

    Full Text Available The change of current value caused by turn-to-turn short circuit of dry-type air-core reactor is so little that failure detection is difficult to be carried out. In order to solve this problem,a new on-line monitoring system based on impedance variation of turn-to-turn short circuit is proposed. The numerical method is applied to analyze the variation of equivalent resistance and equivalent reactance when dry-type air-core reactor winding short circuit happens in different places,and the monitoring method based on harmonic analysis method and quasi- synchronization sampling method is analyzed by theory. The hardware system,which takes single-chip microcomputer as the core of data processing and logic control,completes data acquisition of voltage signal and current signal of the reactor. In the respect of software design,the impedance variation will be uploaded to the PC after it has been calculated by using the above monitoring method,and then monitoring of turn-to-turn short circuit fault will be realized. Finally,the design of on-line monitoring system is studied by testing. The research result shows that,the equivalent resistance increases and the equivalent reactance decreases when turn-to-turn short circuit occurs,and the variation of equivalent resistance is more obvious than equivalent reactance. The experiment results prove that this monitoring method is true and the on-line monitoring system is feasible.

  5. Environmental safety providing during heat insulation works and using thermal insulation materials

    Directory of Open Access Journals (Sweden)

    Velichko Evgeny

    2017-01-01

    Full Text Available This article considers the negative effect of thermal insulating materials and products on human health and environment pollution, particularly in terms of the composition of environmentally hazardous construction products. The authors have analyzed the complex measures for providing ecological safety, sanitary and epidemiological requirements, rules and regulations both during thermal insulation works and throughout the following operation of buildings and premises. The article suggests the protective and preventive measures to reduce and eliminate the negative impact of the proceeding of thermal insulation works on the natural environment and on human health.

  6. COMFORT PROVIDING SYSTEMS IN SPACES WITH ACOUTIC INSULATION

    Directory of Open Access Journals (Sweden)

    Grzegorz KLEKOT

    2014-12-01

    Full Text Available High capacities of currently available devices for sound registering and processing have generated a need for sound insulated spaces dedicated to exchange of confidential information. In such spaces, preventing propagation of vibroacoustic signals both by the way of air and construction elements entails complete insulation of the room. In order to meet this requirement, proper chemical composition of air and stabilized temperature conditions have to be guaranteed. The paper discusses questions related to the process of solving the task of providing thermal comfort and satisfying air quality in a room for confidential discussions. It presents prototype solutions of installations dedicated to stabilize human-friendly conditions inside a modular chamber provided with acoustic insulation.

  7. Cuprous sulfide as a film insulation for superconductors

    International Nuclear Information System (INIS)

    Wagner, G.R.; Uphoff, J.H.; Vecchio, P.D.

    1982-01-01

    The LCP test coil utilizes a conductor of forced-flow design having 486 strands of multifilametary Nb 3 Sn compacted in a stainless steel sheath. The impetus for the work reported here stemmed from the need for some form of insulation for those strands to prevent sintering during reaction and to reduce ac losses. The work reported here experimented with cuprous sulfide coatings at various coating rates and thicknesses. Two solenoids that were wound with cuprous sulfide-coated wires and heat-treated at 700 degrees C were found to demonstrate that the film is effective in providing turn-to-turn insulation for less than about 0.5V between turns. The sulfide layer provided a metal-semiconductor junction which became conducting at roughly 0.5V. Repeated cycling of the coil voltage in excess of that value produced no damage to the sulfide layer. The junction provided self-protection for the coil as long as the upper allowable current density in the sulfide was not exceeded. No training was apparent up to 6.4 T

  8. Foam nests provide context-dependent thermal insulation to embryos of three leptodactylid frogs.

    Science.gov (United States)

    Méndez-Narváez, J; Flechas, S V; Amézquita, A

    2015-01-01

    The choice of adequate breeding habitat and its associated thermoregulatory conditions are thought to be important in the evolution of amphibian reproductive strategies. Among leptodactylid frogs, there is a terrestrial cline in the oviposition sites chosen to build foam nests for eggs. Although several functions have been attributed to foam nests, their role in temperature regulation for embryos is unclear. Here we tested the hypothesis that foam nests buffer embryos from variation in air temperature. We examined the degree of terrestrial nest sites in three species, finding a terrestrial cline of sites in terms of distance from water. We tested whether this nest-insulation effect varied among these species that differ in the degree of terrestrial nest sites and whether translocating nests impacted embryonic mortality. Our results demonstrate a negative effect of translocating aquatic nests to land, inferred from the highest hatching success in natural nests sites. All nests attenuated environmental thermal variation, but more terrestrial nests buffered embryos from a greater range of temperatures than did aquatic ones. Altogether, our data indicate that foam nests insulate embryos from daily temperature fluctuations among leptodactylid frogs with different degrees of terrestrial nests, which may well have contributed to the evolution of this reproductive strategy.

  9. Secondary emission ion analyzer provided with an electron gun for insulating material analysis

    International Nuclear Information System (INIS)

    Blanchard, Bruno; Carrier, Patrick; Marguerite, J.-L.; Rocco, J.-C.

    1976-01-01

    This invention relates to a secondary emission ion analyser, fitted with an electron gun. It is used in the mass spectrometry analysis of electrically insulating bodies. It has already been suggested to bombard the target with an electron beam in conjunction with the beam of primary particles, in order to reduce the space charge near the target. The object of this invention is the application of this known process to appliances of the ion analyser type with a high electric field near the target. Its main characteristic is the use of an electron gun emitting an electron beam through the extraction lens placed opposite the target. The extraction electric field influences the path of the electrons but the electric and mechanical specifications of the electron gun in the invention are such that the target is correctly sprayed by the electron beam [fr

  10. 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.

  11. 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

  12. Thermal insulation

    International Nuclear Information System (INIS)

    Durston, J.G.; Birch, W.; Facer, R.I.; Stuart, R.A.

    1977-01-01

    Reference is made to liquid metal cooled nuclear reactors. In the arrangement described the reactor vessel is clad with thermal insulation comprising a layer of insulating blocks spaced from the wall and from each other; each block is rigidly secured to the wall, and the interspaces are substantially closed against convectional flow of liquid by resilient closure members. A membrane covering is provided for the layer of blocks, with venting means to allow liquid from the reactor vessel to penetrate between the covering and the layer of blocks. The membrane covering may comprise a stainless steel sheet ribbed in orthogonal pattern to give flexibility for the accommodation of thermal strain. The insulating blocks may be comprised of stainless steel or cellular or porous material and may be hollow shells containing ceramic material or gas fillings. (U.K.)

  13. Polytellurophenes provide imaging contrast towards unravelling the structure–property–function relationships in semiconductor:insulator polymer blends

    KAUST Repository

    Jahnke, Ashlee A.

    2015-02-27

    Polymer blends are broadly important in chemical science and chemical engineering and have led to a wide range of commercial products, however their precise structure and phase morphology is often not well understood. Here we show for the first time that π-conjugated polytellurophenes and high-density polyethylene form blends that can serve as active layers in field-effect transistor devices and can be characterized by a variety of element-specific imaging techniques such as STEM and EDX. Changing the hydrocarbon content and degree of branching on the polytellurophene side-chain leads to a variety of blend structures, and these variations can be readily visualized. Characterization by electron microscopy is complemented by topographic and X-ray methods to establish a nano- to micro-scale picture of these systems. We find that blends that possess microscale networks function best as electronic devices; however, contrary to previous notions a strong correlation between nanofiber formation and electrical performance is not observed. Our work demonstrates that use of organometallic polymers assists in clarifying relevant structure–property–function relationships in multicomponent systems such as semiconductor:insulator blends and sheds light on the structure development in polymer:polymer blends including crystallization, phase separation, and formation of supramolecular arrangements.

  14. Polytellurophenes provide imaging contrast towards unravelling the structure–property–function relationships in semiconductor:insulator polymer blends

    KAUST Repository

    Jahnke, Ashlee A.; Yu, Liyang; Coombs, Neil; Scaccabarozzi, Alberto D.; Tilley, Andrew J.; DiCarmine, Paul M.; Amassian, Aram; Stingelin, Natalie; Seferos, Dwight S.

    2015-01-01

    Polymer blends are broadly important in chemical science and chemical engineering and have led to a wide range of commercial products, however their precise structure and phase morphology is often not well understood. Here we show for the first time that π-conjugated polytellurophenes and high-density polyethylene form blends that can serve as active layers in field-effect transistor devices and can be characterized by a variety of element-specific imaging techniques such as STEM and EDX. Changing the hydrocarbon content and degree of branching on the polytellurophene side-chain leads to a variety of blend structures, and these variations can be readily visualized. Characterization by electron microscopy is complemented by topographic and X-ray methods to establish a nano- to micro-scale picture of these systems. We find that blends that possess microscale networks function best as electronic devices; however, contrary to previous notions a strong correlation between nanofiber formation and electrical performance is not observed. Our work demonstrates that use of organometallic polymers assists in clarifying relevant structure–property–function relationships in multicomponent systems such as semiconductor:insulator blends and sheds light on the structure development in polymer:polymer blends including crystallization, phase separation, and formation of supramolecular arrangements.

  15. Improved cable insulation for superconducting magnets

    International Nuclear Information System (INIS)

    Anerella, M.; Ghosh, A.K.; Kelly, E.; Schmalzle, J.; Willen, E.; Fraivillig, J.; Ochsner, J.; Parish, D.J.

    1993-01-01

    Several years ago, Brookhaven joined with DuPont in a cooperative effort to develop improved cable insulation for SSC superconducting dipole magnets. The effort was supported by the SSC Central Design Group and later the SSC Laboratory. It was undertaken because turn-to-turn and midplane shorts were routinely being experienced during the assembly of magnets with coils made of the existing Kapton/fiberglass (K/FG) system of Kapton film overwrapped with epoxy-impregnated fiberglass tape. Dissection of failed magnets showed that insulation disruption and punch-through was occurring near the inner edges of turns close to the magnet midplane. Coil pressures of greater than 17 kpsi were sufficient to disrupt the insulation at local high spots where the cable had been strongly compacted in the keystoning operation during cable manufacture. In the joint development program, numerous combinations of polyimide films manufactured by DuPont with varying configurations and properties (including thickness) were subjected to tests at Brookhaven. Early tests were bench trials using wrapped cable samples. The most promising candidates were used in coils and many of these promising candidates were used in coils and many of these assembled and tested as magnets in both the SSC and RHIC magnet programs currently underway. The Kapton CI (CI) system that has been adopted represents a suitable compromise of numerous competing factors. It exhibits improved performance in the critical parameter of compressive punch-through resistance as well as other advantages over the K/FG system

  16. Improved cable insulation for superconducting magnets

    International Nuclear Information System (INIS)

    Anerella, M.; Ghosh, A.K.; Kelly, E.; Schmalzle, J.; Willen, E.; Fraivillig, J.; Ochsner, J.; Parish, D.J.

    1993-01-01

    Several years ago, Brookhaven joined with DuPont in a cooperative effort to develop improved cable insulation for SSC superconducting dipole magnets. The effort was supported by the SSC Central Design Group and later the SSC Laboratory. It was undertaken because turn-to-turn and midplane shorts were routinely being experienced during the assembly of magnets with coils made of the existing Kapton/Fiberglass (K/FG) system of Kapton film overwrapped with epoxy-impregnated fiberglass tape. Dissection of failed magnets showed that insulation disruption and punch-through was occurring near the inner edges of turns close to the magnet midplane. Coil pressures of greater than 17 kpsi were sufficient to disrupt the insulation at local high spots where wires in neighboring turns crossed one another and where the cable had been strongly compacted in the keystoning operation during cable manufacture. In the joint development program, numerous combinations of polyimide films manufactured by DuPont with varying configurations and properties (including thickness) were subjected to tests at Brookhaven. Early tests were bench trials using wrapped cable samples. The most promising candidates were used in coils and many of these assembled and tested as magnets in both the SSC and RHIC magnet programs currently underway. The Kapton CI (CI) system that has been adopted represents a suitable compromise of numerous competing factors. It exhibits improved performance in the critical parameter of compressive punch-through resistance as well as other advantages over the K/FG system

  17. Panels of microporous insulation

    Energy Technology Data Exchange (ETDEWEB)

    McWilliams, J.A.; Morgan, D.E.; Jackson, J.D.J.

    1990-08-07

    Microporous thermal insulation materials have a lattice structure in which the average interstitial dimension is less than the mean free path of the molecules of air or other gas in which the material is arranged. This results in a heat flow which is less than that attributable to the molecular heat diffusion of the gas. According to this invention, a method is provided for manufacturing panels of microporous thermal insulation, in particular such panels in which the insulation material is bonded to a substrate. The method comprises the steps of applying a film of polyvinyl acetate emulsion to a non-porous substrate, and compacting powdery microporous thermal insulation material against the film so as to cause the consolidated insulation material to bond to the substrate and form a panel. The polyvinyl acetate may be applied by brushing or spraying, and is preferably allowed to dry prior to compacting the insulation material. 1 fig.

  18. Wall insulation system

    Energy Technology Data Exchange (ETDEWEB)

    Kostek, P.T.

    1987-08-11

    In a channel specially designed to fasten semi-rigid mineral fibre insulation to masonry walls, it is known to be constructed from 20 gauge galvanized steel or other suitable material. The channel is designed to have pre-punched holes along its length for fastening of the channel to the drywall screw. The unique feature of the channel is the teeth running along its length which are pressed into the surface of the butted together sections of the insulation providing a strong grip between the two adjacent pieces of insulation. Of prime importance to the success of this system is the recent technological advancements of the mineral fibre itself which allow the teeth of the channel to engage the insulation fully and hold without mechanical support, rather than be repelled or pushed back by the inherent nature of the insulation material. After the insulation is secured to the masonry wall by concrete nail fastening systems, the drywall is screwed to the channel.

  19. Research on vacuum insulation for cryocables

    International Nuclear Information System (INIS)

    Graneau, P.

    1974-01-01

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

  20. 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...

  1. Thermal insulation

    International Nuclear Information System (INIS)

    Aspden, G.J.; Howard, R.S.

    1988-01-01

    The patent concerns high temperature thermal insulation of large vessels, such as the primary vessel of a liquid metal cooled nuclear reactor. The thermal insulation consists of multilayered thermal insulation modules, and each module comprises a number of metal sheet layers sandwiched between a back and front plate. The layers are linked together by straps and clips to control the thickness of the module. (U.K.)

  2. 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.

  3. Thermal insulation

    International Nuclear Information System (INIS)

    Pinsky, G.P.

    1977-01-01

    Thermal insulation for vessels and piping within the reactor containment area of nuclear power plants is disclosed. The thermal insulation of this invention can be readily removed and replaced from the vessels and piping for inservice inspection, can withstand repeated wettings and dryings, and can resist high temperatures for long periods of time. 4 claims, 3 figures

  4. Vacuum foil insulation system

    International Nuclear Information System (INIS)

    Hanson, J.P.; Sabolcik, R.E.; Svedberg, R.C.

    1976-01-01

    In a multifoil thermal insulation package having a plurality of concentric cylindrical cups, means are provided for reducing heat loss from the penetration region which extends through the cups. At least one cup includes an integral skirt extending from one end of the cup to intersection with the penetration means. Assembly of the insulation package with the skirted cup is facilitated by splitting the cup to allow it to be opened up and fitted around the other cups during assembly. The insulation is for an implantable nuclear powered artificial heart

  5. Cooper Pairs in Insulators?

    International Nuclear Information System (INIS)

    Valles, James

    2008-01-01

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

  6. 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, ...

  7. Wrapped Multilayer Insulation

    Science.gov (United States)

    Dye, Scott A.

    2015-01-01

    New NASA vehicles, such as Earth Departure Stage (EDS), Orion, landers, and orbiting fuel depots, need improved cryogenic propellant transfer and storage for long-duration missions. Current cryogen feed line multilayer insulation (MLI) performance is 10 times worse per area than tank MLI insulation. During each launch, cryogenic piping loses approximately 150,000 gallons (equivalent to $300,000) in boil-off during transfer, chill down, and ground hold. Quest Product Development Corp., teaming with Ball Aerospace, developed an innovative advanced insulation system, Wrapped MLI (wMLI), to provide improved thermal insulation for cryogenic feed lines. wMLI is high-performance multilayer insulation designed for cryogenic piping. It uses Quest's innovative discrete-spacer technology to control layer spacing/ density and reduce heat leak. The Phase I project successfully designed, built, and tested a wMLI prototype with a measured heat leak 3.6X lower than spiral-wrapped conventional MLI widely used for piping insulation. A wMLI prototype had a heat leak of 7.3 W/m2, or 27 percent of the heat leak of conventional MLI (26.7 W/m2). The Phase II project is further developing wMLI technology with custom, molded polymer spacers and advancing the product toward commercialization via a rigorous testing program, including developing advanced vacuuminsulated pipe for ground support equipment.

  8. 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)

  9. Insulation structure of thermonuclear device

    International Nuclear Information System (INIS)

    Suzuki, Takayuki; Usami, Saburo; Tsukamoto, Hideo; Kikuchi, Mitsuru

    1998-01-01

    The present invention provides an insulating structure of a thermonuclear device, in which insulation materials between toroidal coils are not broken even if superconductive toroidal coils are used. Namely, a tokamak type thermonuclear device of an insulating structure type comprises superconductive toroidal coils for confining plasmas arranged in a circular shape directing the center each at a predetermined angle, and the toroidal coils are insulated from each other. The insulation materials are formed by using a biaxially oriented fiber reinforced plastics. The contact surface of the toroidal coils and the insulating materials are arranged so that they are contact at a woven surface of the fiber reinforced plastics. Either or both of the contact surfaces of the fiber reinforced plastics and the toroidal coils are coated with a high molecular compound having a low friction coefficient. With such a constitution, since the interlayer shearing strength of the biaxially oriented fiber reinforced plastics is about 1/10 of the compression strength, the shearing stress exerted on the insulation material is reduced. Since a static friction coefficient on the contact surface is reduced to provide a structure causing slipping, shearing stress does not exceeds a predetermined limit. As a result, breakage of the insulation materials between the toroidal coils can be prevented. (I.S.)

  10. Tank Insulation

    Science.gov (United States)

    1979-01-01

    For NASA's Apollo program, McDonnell Douglas Astronautics Company, Huntington Beach, California, developed and built the S-IVB, uppermost stage of the three-stage Saturn V moonbooster. An important part of the development task was fabrication of a tank to contain liquid hydrogen fuel for the stage's rocket engine. The liquid hydrogen had to be contained at the supercold temperature of 423 degrees below zero Fahrenheit. The tank had to be perfectly insulated to keep engine or solar heat from reaching the fuel; if the hydrogen were permitted to warm up, it would have boiled off, or converted to gaseous form, reducing the amount of fuel available to the engine. McDonnell Douglas' answer was a supereffective insulation called 3D, which consisted of a one-inch thickness of polyurethane foam reinforced in three dimensions with fiberglass threads. Over a 13-year development and construction period, the company built 30 tanks and never experienced a failure. Now, after years of additional development, an advanced version of 3D is finding application as part of a containment system for transporting Liquefied Natural Gas (LNG) by ship.

  11. Heat insulating plates

    Energy Technology Data Exchange (ETDEWEB)

    Allan, J.A.F.

    1976-10-28

    Micro-porous insulation plates are dealt with, for example, how they are used in the insulation of heat storage devices. Since one side of such plates is exposed to a temperature of over 700/sup 0/C, a shrinkage of the glass texture of the covering can occur, which can exceed the shrinkage of the inner micro-porous material, so that cracks and splits in the high temperature side of the covering can come about. The task of the invention is to design the plate in such a way as to prevent this from happening. For this purpose the plate is provided, according to invention specifications, with flutes, waves, ribs, waffle or grid patterns and the covering is set into the recesses originating from this.

  12. Super-insulation

    International Nuclear Information System (INIS)

    Gerold, J.

    1985-01-01

    The invention concerns super-insulation, which also acts as spacing between two pressurized surfaces, where the crossing bars in at least two layers are provided, with interposed foil. The super-insulation is designed so that it can take compression forces and limits thermal radiation and thermal conduction sufficiently, where the total density of heat flow is usually limited to a few watts per m 2 . The solution to the problem is characterized by the fact that the bars per layer are parallel and from layer to layer they are at an angle to each other and the crossover positions of the bars of different layers are at fixed places and so form contact columns. The basic idea is that bars crossing over each other to support compression forces are used so that contact columns are formed, which are compressed to a certain extent by the load. (orig./PW) [de

  13. Metal-as-insulation variant of no-insulation HTS winding technique: pancake tests under high background magnetic field and high current at 4.2 K

    Science.gov (United States)

    Lécrevisse, T.; Badel, A.; Benkel, T.; Chaud, X.; Fazilleau, P.; Tixador, P.

    2018-05-01

    In the framework of a project aiming at fabricating a 10 T high temperature superconducting (HTS) insert to operate in a 20 T background field, we are investigating the behavior of pancakes consisting of a REBCO HTS tape co-wound with a stainless steel tape (metal-as-insulation (MI) coil). The MI winding is inducing a significant turn-to-turn electrical resistance which helps to reduce the charging time delay. Despite this resistance, the self-protection feature of no-insulation coils is still enabled, thanks to the voltage limit of the power supply. We have built a single pancake coil representative of the pancake that will be used in the insert and performed tests under very high background magnetic field. Our coil experienced over 100 heater induced quenches without a measureable increase of its internal resistance. We have gathered stability and quench behavior data for magnetic fields and engineering current densities (je ) in the range of 0–17 T and 0–635 A mm‑2 respectively. We also present our very first experiments on the insert/outsert interaction in the case of a resistive magnet fault. We show that if self-protection of the MI winding is really effective in the case of a MI coil quench, a major issue comes from the outsert fault which induces a huge current inside the MI coil.

  14. Process insulation. Isolation thermique des equipements

    Energy Technology Data Exchange (ETDEWEB)

    1987-01-01

    A manual is presented to assist managers and operating personnel to recognize industrial energy management opportunities, and provides mathematical equations, general information on proven techniques and technology, and examples. It deals with process insulation, focusing on the insulation of mechanical systems such as piping, process vessels, equipment, and ductwork. The manual describes the effects of insulation materials; commonly encountered types of insulation, coverings and protective finishes as well as common applications; energy management opportunities, divided into housekeeping, low cost, and retrofit; and includes worked examples of each. Includes glossary. 17 figs., 8 tabs.

  15. Economically optimal thermal insulation

    Energy Technology Data Exchange (ETDEWEB)

    Berber, J.

    1978-10-01

    Exemplary calculations to show that exact adherence to the demands of the thermal insulation ordinance does not lead to an optimal solution with regard to economics. This is independent of the mode of financing. Optimal thermal insulation exceeds the values given in the thermal insulation ordinance.

  16. Thermal insulating panel

    Energy Technology Data Exchange (ETDEWEB)

    Hughes, J.T.

    1985-09-11

    A panel of thermal insulation material has at least one main portion which comprises a dry particulate insulation material compressed within a porous envelope so that it is rigid or substantially rigid and at least one auxiliary portion which is secured to and extends along at least one of the edges of the main portions. The auxiliary portions comprise a substantially uncompressed dry particulate insulation material contained within an envelope. The insulation material of the auxiliary portion may be the same as or may be different from the insulation material of the main portion. The envelope of the auxiliary portion may be made of a porous or a non-porous material. (author).

  17. Topological insulators fundamentals and perspectives

    CERN Document Server

    Ortmann, Frank; Valenzuela, Sergio O

    2015-01-01

    There are only few discoveries and new technologies in physical sciences that have the potential to dramatically alter and revolutionize our electronic world. Topological insulators are one of them. The present book for the first time provides a full overview and in-depth knowledge about this hot topic in materials science and condensed matter physics. Techniques such as angle-resolved photoemission spectrometry (ARPES), advanced solid-state Nuclear Magnetic Resonance (NMR) or scanning-tunnel microscopy (STM) together with key principles of topological insulators such as spin-locked electronic

  18. Floquet topological insulators for sound

    Science.gov (United States)

    Fleury, Romain; Khanikaev, Alexander B.; Alù, Andrea

    2016-06-01

    The unique conduction properties of condensed matter systems with topological order have recently inspired a quest for the similar effects in classical wave phenomena. Acoustic topological insulators, in particular, hold the promise to revolutionize our ability to control sound, allowing for large isolation in the bulk and broadband one-way transport along their edges, with topological immunity against structural defects and disorder. So far, these fascinating properties have been obtained relying on moving media, which may introduce noise and absorption losses, hindering the practical potential of topological acoustics. Here we overcome these limitations by modulating in time the acoustic properties of a lattice of resonators, introducing the concept of acoustic Floquet topological insulators. We show that acoustic waves provide a fertile ground to apply the anomalous physics of Floquet topological insulators, and demonstrate their relevance for a wide range of acoustic applications, including broadband acoustic isolation and topologically protected, nonreciprocal acoustic emitters.

  19. Topological insulators and topological superconductors

    CERN Document Server

    Bernevig, Andrei B

    2013-01-01

    This graduate-level textbook is the first pedagogical synthesis of the field of topological insulators and superconductors, one of the most exciting areas of research in condensed matter physics. Presenting the latest developments, while providing all the calculations necessary for a self-contained and complete description of the discipline, it is ideal for graduate students and researchers preparing to work in this area, and it will be an essential reference both within and outside the classroom. The book begins with simple concepts such as Berry phases, Dirac fermions, Hall conductance and its link to topology, and the Hofstadter problem of lattice electrons in a magnetic field. It moves on to explain topological phases of matter such as Chern insulators, two- and three-dimensional topological insulators, and Majorana p-wave wires. Additionally, the book covers zero modes on vortices in topological superconductors, time-reversal topological superconductors, and topological responses/field theory and topolo...

  20. Magnetically insulated H- diodes

    International Nuclear Information System (INIS)

    Fisher, A.; Bystritskii, V.; Garate, E.; Prohaska, R.; Rostoker, N.

    1993-01-01

    At the Univ. of California, Irvine, the authors have been studying the production of intense H - beams using pulse power techniques for the past 7 years. Previously, current densities of H - ions for various diode designs at UCI have been a few A/cm 2 . Recently, they have developed diodes similar to the coaxial design of the Lebedev Physical Institute, Moscow, USSR, where current densities of up to 200 A/cm 2 were reported using nuclear activation of a carbon target. In experiments at UCI employing the coaxial diode, current densities of up to 35 A/cm 2 from a passive polyethylene cathode loaded with TiH 2 have been measured using a pinhole camera and CR-39 track recording plastic. The authors have also been working on a self-insulating, annular diode which can generate a directed beam of H - ions. In the annular diode experiments a plasma opening switch was used to provide a prepulse and a current path which self-insulated the diode. These experiments were done on the machine APEX, a 1 MV, 50 ns, 7 Ω pulseline with a unipolar negative prepulse of ∼ 100 kV and 400 ns duration. Currently, the authors are modifying the pulseline to include an external LC circuit which can generate a bipolar, 150 kV, 1 μs duration prepulse (similar prepulse characteristic as in the Lebedev Institute experiments cited above)

  1. Measure Guideline. Internal Insulation of Masonry Walls

    Energy Technology Data Exchange (ETDEWEB)

    Straube, J. F. [Building Science Corporation (BSC), Somerville, MA (United States); Ueno, K. [Building Science Corporation (BSC), Somerville, MA (United States); Schumacher, C. J. [Building Science Corporation (BSC), Somerville, MA (United States)

    2012-07-01

    This measure guideline provides recommendations for interior insulation assemblies that control interstitial condensation and durability risks; recommendations for acceptable thermal performance are also provided. An illustrated guide of high-risk exterior details (which concentrate bulk water), and recommended remediation details is provided. This is followed by a recommended methodology for risk assessment of a masonry interior insulation project: a series of steps are suggested to assess the risks associated with this retrofit, with greater certainty with added steps.

  2. Measure Guideline: Internal Insulation of Masonry Walls

    Energy Technology Data Exchange (ETDEWEB)

    Straube, J. F.; Ueno, K.; Schumacher, C. J.

    2012-07-01

    This measure guideline provides recommendations for interior insulation assemblies that control interstitial condensation and durability risks; recommendations for acceptable thermal performance are also provided. An illustrated guide of high-risk exterior details (which concentrate bulk water), and recommended remediation details is provided. This is followed by a recommended methodology for risk assessment of a masonry interior insulation project: a series of steps are suggested to assess the risks associated with this retrofit, with greater certainty with added steps.

  3. Slab edge insulating form system and methods

    Science.gov (United States)

    Lee, Brain E [Corral de Tierra, CA; Barsun, Stephan K [Davis, CA; Bourne, Richard C [Davis, CA; Hoeschele, Marc A [Davis, CA; Springer, David A [Winters, CA

    2009-10-06

    A method of forming an insulated concrete foundation is provided comprising constructing a foundation frame, the frame comprising an insulating form having an opening, inserting a pocket former into the opening; placing concrete inside the foundation frame; and removing the pocket former after the placed concrete has set, wherein the concrete forms a pocket in the placed concrete that is accessible through the opening. The method may further comprise sealing the opening by placing a sealing plug or sealing material in the opening. A system for forming an insulated concrete foundation is provided comprising a plurality of interconnected insulating forms, the insulating forms having a rigid outer member protecting and encasing an insulating material, and at least one gripping lip extending outwardly from the outer member to provide a pest barrier. At least one insulating form has an opening into which a removable pocket former is inserted. The system may also provide a tension anchor positioned in the pocket former and a tendon connected to the tension anchor.

  4. Improved DC Gun Insulator Assembly

    International Nuclear Information System (INIS)

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

    2010-01-01

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

  5. 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....

  6. Measure Guideline. Hybrid Foundation Insulation Retrofits

    Energy Technology Data Exchange (ETDEWEB)

    Ueno, K. [Building Science Corporation, Somerville, MA (United States); Lstiburek, J. [Building Science Corporation, Somerville, MA (United States)

    2012-05-01

    This measure guideline provides recommendations for designs and variations for retrofit hybrid assemblies in improving interior foundation insulation and water management of basements. Variations include closed cell spray foam (ccSPF) with membrane waterproofing or air gap membrane drainage layers, rigid board foam insulation at flat walls (cast concrete or CMU block), a “partial drainage” detail making use of the bulk water drainage that occurs through the field of a rubble stone wall, and non-drained spray foam assemblies (including slab insulation).

  7. Measure Guideline: Hybrid Foundation Insulation Retrofits

    Energy Technology Data Exchange (ETDEWEB)

    Ueno, K.; Lstiburek, J.

    2012-05-01

    This measure guideline provides recommendations for designs and variations for retrofit hybrid assemblies in improving interior foundation insulation and water management of basements. Variations include closed cell spray foam (ccSPF) with membrane waterproofing or air gap membrane drainage layers, rigid board foam insulation at flat walls (cast concrete or CMU block), a 'partial drainage' detail making use of the bulk water drainage that occurs through the field of a rubble stone wall, and non-drained spray foam assemblies (including slab insulation).

  8. Silicon on insulator self-aligned transistors

    Science.gov (United States)

    McCarthy, Anthony M.

    2003-11-18

    A method for fabricating thin-film single-crystal silicon-on-insulator (SOI) self-aligned transistors. Standard processing of silicon substrates is used to fabricate the transistors. Physical spaces, between the source and gate, and the drain and gate, introduced by etching the polysilicon gate material, are used to provide connecting implants (bridges) which allow the transistor to perform normally. After completion of the silicon substrate processing, the silicon wafer is bonded to an insulator (glass) substrate, and the silicon substrate is removed leaving the transistors on the insulator (glass) substrate. Transistors fabricated by this method may be utilized, for example, in flat panel displays, etc.

  9. Polyimide Foams Offer Superior Insulation

    Science.gov (United States)

    2012-01-01

    At Langley Research Center, Erik Weiser and his colleagues in the Advanced Materials and Processing Branch were working with a new substance for fabricating composites for use in supersonic aircraft. The team, however, was experiencing some frustration. Every time they tried to create a solid composite from the polyimide (an advanced polymer) material, it bubbled and foamed. It seemed like the team had reached a dead end in their research - until they had another idea. "We said, This isn t going to work for composites, but maybe we could make a foam out of it," Weiser says. "That was kind of our eureka moment, to see if we could go in a whole other direction. And it worked." Weiser and his colleagues invented a new kind of polyimide foam insulation they named TEEK. The innovation displayed a host of advantages over existing insulation options. Compared to other commercial foams, Weiser explains, polyimide foams perform well across a broad range of temperatures, noting that the NASA TEEK foams provide effective structural insulation up to 600 F and down to cryogenic temperatures. The foam does not burn or off-gas toxic fumes, and even at -423 F - the temperature of liquid hydrogen - the material stays flexible. The inventors could produce the TEEK foam at a range of densities, from 0.5 pounds per cubic foot up to 20 pounds per cubic foot, making the foam ideal for a range of applications, including as insulation for reusable launch vehicles and for cryogenic tanks and lines. They also developed a unique, friable balloon format for manufacturing the foam, producing it as hollow microspheres that allowed the foam to be molded and then cured into any desired shape - perfect for insulating pipes of different sizes and configurations. The team s originally unplanned invention won an "R&D 100" award, and a later form of the foam, called LaRC FPF-44 (Spinoff 2009), was named "NASA Invention of the Year" in 2007.

  10. Heat insulation support device

    International Nuclear Information System (INIS)

    Takahashi, Hiroyuki; Koda, Tomokazu; Motojima, Osamu; Yamamoto, Junya.

    1994-01-01

    The device of the present invention comprises a plurality of heat insulation legs disposed in a circumferential direction. Each of the heat insulative support legs has a hollow shape, and comprises an outer column and an inner column as support structures having a heat insulative property (heat insulative structure), and a thermal anchor which absorbs compulsory displacement by a thin flat plate (displacement absorber). The outer column, the thermal anchor and the inner column are connected by a support so as to offset the positional change of objects to be supported due to shrinkage when they are shrunk. In addition, the portion between the superconductive coils as the objects to be supported and the inner column is connected by the support. The superconductive thermonuclear device is entirely contained in a heat insulative vacuum vessel, and the heat insulative support legs are disposed on a lower lid of the heat insulative vacuum vessel. With such a constitution, they are strengthened against lateral load and buckling, thereby enabling to reduce the amount of heat intrusion while keeping the compulsory displacement easy to be absorbed. (I.N.)

  11. Labeling and advertising of home insulation

    Energy Technology Data Exchange (ETDEWEB)

    1978-07-01

    This staff report, prepared by the F.T.C.'s Bureau of Consumer Protection for Commission review, includes recommendations as to the final form of a trade regulation rule relating to the labeling and advertising of home insulation. Because of marketing abuses which accompanied the rising demand for home insulation, there has been broad support for a rule requiring information disclosures to help purchasers of home insulation to make an informed decision. The Commission, to provide such rule as quickly as possible, undertook its rulemaking proceeding under its new expedited rulemaking procedure. The rule was proposed on November 18, 1977, and, following a two-month period for written comments, four weeks of hearings were held in Washington, D.C. in February 1978. The record, contributed to by a variety of interests, shows that consumers do not know how to shop for home insulation. The staff-recommended rule, among other things, would require that insulation be tested and R-values (a measure of insulation's ability to retain heat) disclosed on labels and in advertising. To facilitate comparison shopping, the industry would also be required to furnish consumers with fact sheets describing, on a product-to-product basis, factors that can reduce the R-value of insulation.

  12. 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.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2013-12-15

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

  14. KSI's Cross Insulated Core Transformer Technology

    International Nuclear Information System (INIS)

    Uhmeyer, Uwe

    2009-01-01

    Cross Insulated Core Transformer (CCT) technology improves on Insulated Core Transformer (ICT) implementations. ICT systems are widely used in very high voltage, high power, power supply systems. In an ICT transformer ferrite core sections are insulated from their neighboring ferrite cores. Flux leakage is present at each of these insulated gaps. The flux loss is raised to the power of stages in the ICT design causing output voltage efficiency to taper off with increasing stages. KSI's CCT technology utilizes a patented technique to compensate the flux loss at each stage of an ICT system. Design equations to calculate the flux compensation capacitor value are presented. CCT provides corona free operation of the HV stack. KSI's CCT based High Voltage power supply systems offer high efficiency operation, high frequency switching, low stored energy and smaller size over comparable ICT systems.

  15. Corrosion-under-insulation (CUI) guidelines

    CERN Document Server

    Staff, European Federation of Corrosion; Winnik, S

    2014-01-01

    Corrosion under insulation (CUI) refers to the external corrosion of piping and vessels that occurs underneath externally clad/jacketed insulation as a result of the penetration of water. By its very nature CUI tends to remain undetected until the insulation and cladding/jacketing is removed to allow inspection or when leaks occur. CUI is a common problem shared by the refining, petrochemical, power, industrial, onshore and offshore industries. The European Federation of Corrosion (EFC) Working Parties WP13 and WP15 have worked to provide guidelines on managing CUI together with a number of major European refining, petrochemical and offshore companies including BP, Chevron-Texaco, Conoco-Phillips, ENI, Exxon-Mobil, IFP, MOL, Scanraff, Statoil, Shell, Total and Borealis. The guidelines within this document are intended for use on all plants and installations that contain insulated vessels, piping and equipment. The guidelines cover a risk-based inspection methodology for CUI, inspection techniques (including n...

  16. Load responsive multilayer insulation performance testing

    International Nuclear Information System (INIS)

    Dye, S.; Kopelove, A.; Mills, G. L.

    2014-01-01

    Cryogenic insulation designed to operate at various pressures from one atmosphere to vacuum, with high thermal performance and light weight, is needed for cryogenically fueled space launch vehicles and aircraft. Multilayer insulation (MLI) performs well in a high vacuum, but the required vacuum shell for use in the atmosphere is heavy. Spray-on foam insulation (SOFI) is often used in these systems because of its light weight, but can have a higher heat flux than desired. We report on the continued development of Load Responsive Multilayer Insulation (LRMLI), an advanced thermal insulation system that uses dynamic beam discrete spacers that provide high thermal performance both in atmosphere and vacuum. LRMLI consists of layers of thermal radiation barriers separated and supported by micromolded polymer spacers. The spacers have low thermal conductance, and self-support a thin, lightweight vacuum shell that provides internal high vacuum in the insulation. The dynamic load responsive spacers compress to support the external load of a vacuum shell in one atmosphere, and decompress under reduced atmospheric pressure for lower heat leak. Structural load testing was performed on the spacers with various configurations. LRMLI was installed on a 400 liter tank and boil off testing with liquid nitrogen performed at various chamber pressures from one atmosphere to high vacuum. Testing was also performed with an MLI blanket on the outside of the LRMLI

  17. Load responsive multilayer insulation performance testing

    Energy Technology Data Exchange (ETDEWEB)

    Dye, S.; Kopelove, A. [Quest Thermal Group, 6452 Fig Street Suite A, Arvada, CO 80004 (United States); Mills, G. L. [Ball Aerospace and Technologies Corp, 1600 Commerce Street, Boulder, CO 80301 (United States)

    2014-01-29

    Cryogenic insulation designed to operate at various pressures from one atmosphere to vacuum, with high thermal performance and light weight, is needed for cryogenically fueled space launch vehicles and aircraft. Multilayer insulation (MLI) performs well in a high vacuum, but the required vacuum shell for use in the atmosphere is heavy. Spray-on foam insulation (SOFI) is often used in these systems because of its light weight, but can have a higher heat flux than desired. We report on the continued development of Load Responsive Multilayer Insulation (LRMLI), an advanced thermal insulation system that uses dynamic beam discrete spacers that provide high thermal performance both in atmosphere and vacuum. LRMLI consists of layers of thermal radiation barriers separated and supported by micromolded polymer spacers. The spacers have low thermal conductance, and self-support a thin, lightweight vacuum shell that provides internal high vacuum in the insulation. The dynamic load responsive spacers compress to support the external load of a vacuum shell in one atmosphere, and decompress under reduced atmospheric pressure for lower heat leak. Structural load testing was performed on the spacers with various configurations. LRMLI was installed on a 400 liter tank and boil off testing with liquid nitrogen performed at various chamber pressures from one atmosphere to high vacuum. Testing was also performed with an MLI blanket on the outside of the LRMLI.

  18. Survey of thermal insulation systems

    International Nuclear Information System (INIS)

    Kinoshita, Izumi

    1983-01-01

    Better thermal insulations have been developed to meet the growing demands of industry, and studies on thermal insulation at both high temperature and low temperature have been widely performed. The purpose of this survey is to summarize data on the performances and characteristics of thermal insulation materials and thermal insulation structures (for instance, gas cooled reactors, space vehicles and LNG storage tanks), and to discuss ravious problems regarding the design of thermal insulation structures of pool-type LMFBRs. (author)

  19. Characterization of Microporous Insulation, Microsil

    Energy Technology Data Exchange (ETDEWEB)

    Thomas, R. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)

    2017-06-15

    Microsil microporous insulation has been characterized by Lawrence Livermore National Laboratory for possible use in structural and thermal applications in the DPP-1 design. Qualitative test results have provided mechanical behavioral characteristics for DPP-1 design studies and focused on the material behavioral response to being crushed, cyclically loaded, and subjected to vibration for a confined material with an interference fit or a radial gap. Quantitative test results have provided data to support the DPP-1 FEA model analysis and verification and were used to determine mechanical property values for the material under a compression load. The test results are documented within this report.

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

    International Nuclear Information System (INIS)

    Calixto, M; Romera, E

    2015-01-01

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

  1. Compact gas-insulated transformer. Fourteenth quarterly report

    Energy Technology Data Exchange (ETDEWEB)

    1983-08-01

    Objective is to develop a compact, more efficient, quieter transformer which does not rely on mineral oil insulation. Compressed SF/sub 6/ is used as the external insulation and polymer film as the insulation between turns. A separate liquid cooling system is also provided. This document reports progress made in design, mechanical, dielectric, short circuit, thermal, materials, prototype, accessories, commercialization, and system studies. (DLC)

  2. Reusable Surface Insulation

    Science.gov (United States)

    1997-01-01

    Advanced Flexible Reusable Surface Insulation, developed by Ames Research Center, protects the Space Shuttle from the searing heat that engulfs it on reentry into the Earth's atmosphere. Initially integrated into the Space Shuttle by Rockwell International, production was transferred to Hi-Temp Insulation Inc. in 1974. Over the years, Hi-Temp has created many new technologies to meet the requirements of the Space Shuttle program. This expertise is also used commercially, including insulation blankets to cover aircrafts parts, fire barrier material to protect aircraft engine cowlings and aircraft rescue fire fighter suits. A Fire Protection Division has also been established, offering the first suit designed exclusively by and for aircraft rescue fire fighters. Hi-Temp is a supplier to the Los Angeles City Fire Department as well as other major U.S. civil and military fire departments.

  3. Insulators for fusion applications

    International Nuclear Information System (INIS)

    1987-04-01

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

  4. Sheath insulator final test report, TFE Verification Program

    International Nuclear Information System (INIS)

    1994-07-01

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

  5. Sheath insulator final test report, TFE Verification Program

    Energy Technology Data Exchange (ETDEWEB)

    1994-07-01

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

  6. Radiation-resistant plastic insulators

    International Nuclear Information System (INIS)

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

    1975-01-01

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

  7. Thermal insulation coating based on water-based polymer dispersion

    Directory of Open Access Journals (Sweden)

    Panchenko Iuliia

    2018-01-01

    Full Text Available For Russia, due to its long winter period, improvement of thermal insulation properties of envelope structures by applying thermal insulation paint and varnish coating to its inner surface is considered perspective. Thermal insulation properties of such coatings are provided by adding aluminosilicate microspheres and aluminum pigment to their composition. This study was focused on defining the effect of hollow aluminosilicate microspheres and aluminum pigment on the paint thermal insulation coating based on water-based polymer dispersion and on its optimum filling ratio. The optimum filling ratio was determined using the method of critical pigment volume concentration (CPVC. The optimum filling ratio was found equal to 55%.

  8. Insulation Reformulation Development

    Science.gov (United States)

    Chapman, Cynthia; Bray, Mark

    2015-01-01

    The current Space Launch System (SLS) internal solid rocket motor insulation, polybenzimidazole acrylonitrile butadiene rubber (PBI-NBR), is a new insulation that replaced asbestos-based insulations found in Space Shuttle heritage solid rocket boosters. PBI-NBR has some outstanding characteristics such as an excellent thermal erosion resistance, low thermal conductivity, and low density. PBI-NBR also has some significant challenges associated with its use: Air entrainment/entrapment during manufacture and lay-up/cure and low mechanical properties such as tensile strength, modulus, and fracture toughness. This technology development attempted to overcome these challenges by testing various reformulated versions of booster insulation. The results suggest the SLS program should continue to investigate material alternatives for potential block upgrades or use an entirely new, more advanced booster. The experimental design was composed of a logic path that performs iterative formulation and testing in order to maximize the effort. A lab mixing baseline was developed and documented for the Rubber Laboratory in Bldg. 4602/Room 1178.

  9. 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-Based...

  10. 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.

  11. Nuclear reactor vessel fuel thermal insulating barrier

    Science.gov (United States)

    Keegan, C. Patrick; Scobel, James H.; Wright, Richard F.

    2013-03-19

    The reactor vessel of a nuclear reactor installation which is suspended from the cold leg nozzles in a reactor cavity is provided with a lower thermal insulating barrier spaced from the reactor vessel that has a hemispherical lower section that increases in volume from the center line of the reactor to the outer extent of the diameter of the thermal insulating barrier and smoothly transitions up the side walls of the vessel. The space between the thermal insulating harrier and the reactor vessel forms a chamber which can be flooded with cooling water through passive valving to directly cool the reactor vessel in the event of a severe accident. The passive inlet valve for the cooling water includes a buoyant door that is normally maintained sealed under its own weight and floats open when the cavity is Hooded. Passively opening steam vents are also provided.

  12. Integrated Multilayer Insulation

    Science.gov (United States)

    Dye, Scott

    2009-01-01

    Integrated multilayer insulation (IMLI) is being developed as an improved alternative to conventional multilayer insulation (MLI), which is more than 50 years old. A typical conventional MLI blanket comprises between 10 and 120 metallized polymer films separated by polyester nets. MLI is the best thermal- insulation material for use in a vacuum, and is the insulation material of choice for spacecraft and cryogenic systems. However, conventional MLI has several disadvantages: It is difficult or impossible to maintain the desired value of gap distance between the film layers (and consequently, it is difficult or impossible to ensure consistent performance), and fabrication and installation are labor-intensive and difficult. The development of IMLI is intended to overcome these disadvantages to some extent and to offer some additional advantages over conventional MLI. The main difference between IMLI and conventional MLI lies in the method of maintaining the gaps between the film layers. In IMLI, the film layers are separated by what its developers call a micro-molded discrete matrix, which can be loosely characterized as consisting of arrays of highly engineered, small, lightweight, polymer (typically, thermoplastic) frames attached to, and placed between, the film layers. The term "micro-molded" refers to both the smallness of the frames and the fact that they are fabricated in a process that forms precise small features, described below, that are essential to attainment of the desired properties. The term "discrete" refers to the nature of the matrix as consisting of separate frames, in contradistinction to a unitary frame spanning entire volume of an insulation blanket.

  13. Energy conservation through thermally insulated structures

    International Nuclear Information System (INIS)

    Abu-Dayyeh, Ayoub

    2006-01-01

    The propose of this paper is to explicate its title through investigating the different available thermal insulating materials and the various techniques of application, as practiced in Jordan, in particular, and as practiced in many parts of the world in general, which will satisfy Jordanian standards in terms of heat transmittance and thermal comfort. A brief comparison with international standards will shed some light on the stringent measures enforced in the developed world and on our striving aspirations to keep pace. The paper consists of four main parts, pseudoally divided. The first part will deal with the mechanism of heat loss and heat gain in structures during summer and winter. It will also explain the Time-lag phenomenon which is vital for providing thermal comfort inside the dwellings. The second part will evaluate the damages induced by the temperature gradients on the different elements of the structure, particularly next to exterior opening. The paper will also demonstrate the damages induced by water condensation and fungus growth on the internal surfaces of the structure and within its skeleton. A correlation between condensation and thermal insulation will be established. The third part of the paper will evaluate the different available thermal insulating materials and the application techniques which will satisfy the needs for thermal insulating and thermal comfort at the least cost possible. The criteria of an economical design shall be established. As a conclusion, the paper infers answers to the following different criteria discussed throughout the different parts of the paper. The main theme of questions can be summarized as follows: 1)How energy conservation is possible due to thermal insulation? 2)The feasibility of investing in thermal insulation? 3)Is thermal comfort and a healthy atmosphere possible inside the dwellings during all season! What are the conditions necessary to sustain them? 4)What environmental impacts can exist due to

  14. Insulation systems of the building construtions

    Directory of Open Access Journals (Sweden)

    Rumiantcev Boris

    2016-01-01

    Full Text Available Constructions of the exterior insulation and decoration combines materials of different functionality and constructive solutions allows to these materials to demonstrate their efficiency to the great extent. Fire safety of buildings is mandatory requirement for building systems. Some insulating material may belong to the group of combustible, but their use in structures so as to minimize the risk of fire. On the other hand, there are special designs, in which non-flammable insulation acts as a flame retardant barrier. In the article carried systematization of construction systems used in the flat and pitched roof during the insulation and wall covering and facades. Taking into account the experience of leading firms were considered the application features of using exterior finish systems: construction solutions, requirements for materials and recommendations about the installation these systems.The article deals with the construction ventilated roofing system of two types: flat roof and pitched roof seam. In the first case, the ventilation system is created using milled insulation boards in the second - by a ventilated gap. In both cases the natural convection of air in the air cavities. Ensuring operational stability insulation is laid on the stages of production of heat-insulating materials. It is important: firstly responsible execution of all process operations associated with providing regulatory properties of materials and secondly, the performance of additional operations associated with the produc-tion of materials, working in a specific design. An example of a material whose properties can modify for a particular application, are milled mineral wool (with air channels for systems of ventilated flat roof.

  15. The Insulation of Houses against Noise from Aircraft in Flight.

    Science.gov (United States)

    Scholes, W. E.; Parkin, P. H.

    Three groups of traditional houses were insulated against aircraft noise by double glazing and installing sound attenuating ventilator units. For upper floor rooms of two story houses, overall insulations of 35-40 dB were obtainable, providing transmission through the roofs and down flues were also reduced. The noise levels caused by ventilator…

  16. Spin-polarized tunneling through a ferromagnetic insulator

    NARCIS (Netherlands)

    Kok, M.; Kok, M.; Beukers, J.N.; Brinkman, Alexander

    2009-01-01

    The polarization of the tunnel conductance of spin-selective ferromagnetic insulators is modeled, providing a generalized concept of polarization including both the effects of electrode and barrier polarization. The polarization model is extended to take additional non-spin-polarizing insulating

  17. Metal-insulator transitions

    Science.gov (United States)

    Imada, Masatoshi; Fujimori, Atsushi; Tokura, Yoshinori

    1998-10-01

    Metal-insulator transitions are accompanied by huge resistivity changes, even over tens of orders of magnitude, and are widely observed in condensed-matter systems. This article presents the observations and current understanding of the metal-insulator transition with a pedagogical introduction to the subject. Especially important are the transitions driven by correlation effects associated with the electron-electron interaction. The insulating phase caused by the correlation effects is categorized as the Mott Insulator. Near the transition point the metallic state shows fluctuations and orderings in the spin, charge, and orbital degrees of freedom. The properties of these metals are frequently quite different from those of ordinary metals, as measured by transport, optical, and magnetic probes. The review first describes theoretical approaches to the unusual metallic states and to the metal-insulator transition. The Fermi-liquid theory treats the correlations that can be adiabatically connected with the noninteracting picture. Strong-coupling models that do not require Fermi-liquid behavior have also been developed. Much work has also been done on the scaling theory of the transition. A central issue for this review is the evaluation of these approaches in simple theoretical systems such as the Hubbard model and t-J models. Another key issue is strong competition among various orderings as in the interplay of spin and orbital fluctuations. Experimentally, the unusual properties of the metallic state near the insulating transition have been most extensively studied in d-electron systems. In particular, there is revived interest in transition-metal oxides, motivated by the epoch-making findings of high-temperature superconductivity in cuprates and colossal magnetoresistance in manganites. The article reviews the rich phenomena of anomalous metallicity, taking as examples Ti, V, Cr, Mn, Fe, Co, Ni, Cu, and Ru compounds. The diverse phenomena include strong spin and

  18. 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.

  19. 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.

  20. Compact vacuum insulation embodiments

    Science.gov (United States)

    Benson, D.K.; Potter, T.F.

    1992-04-28

    An ultra-thin compact vacuum insulation panel is comprised of two hard, but bendable metal wall sheets closely spaced apart from each other and welded around the edges to enclose a vacuum chamber. Glass or ceramic spacers hold the wall sheets apart. The spacers can be discrete spherical beads or monolithic sheets of glass or ceramic webs with nodules protruding therefrom to form essentially point' or line' contacts with the metal wall sheets. In the case of monolithic spacers that form line' contacts, two such spacers with the line contacts running perpendicular to each other form effectively point' contacts at the intersections. Corrugations accommodate bending and expansion, tubular insulated pipes and conduits, and preferred applications are also included. 26 figs.

  1. Compact vacuum insulation

    Science.gov (United States)

    Benson, D.K.; Potter, T.F.

    1993-01-05

    An ultra-thin compact vacuum insulation panel is comprised of two hard, but bendable metal wall sheets closely spaced apart from each other and welded around the edges to enclose a vacuum chamber. Glass or ceramic spacers hold the wall sheets apart. The spacers can be discrete spherical beads or monolithic sheets of glass or ceramic webs with nodules protruding therefrom to form essentially point'' or line'' contacts with the metal wall sheets. In the case of monolithic spacers that form line'' contacts, two such spacers with the line contacts running perpendicular to each other form effectively point'' contacts at the intersections. Corrugations accommodate bending and expansion, tubular insulated pipes and conduits, and preferred applications are also included.

  2. Insulating materials for optoelectronics

    International Nuclear Information System (INIS)

    Agullo-Lopez, F.

    1990-01-01

    Optoelectronics is an interdisciplinary field. Basic functions of an optoelectronic system include the generator of the optical signal, its transmission and handling and, finally, its detection, storage and display. A large variety of semiconductor and insulating materials are used or are being considered to perform those functions. The authors focus on insulating materials, mostly oxides. For signal generation, tunable solid state lasers, either vibronic or those based oon colour centres are briefly described, and their main operating parameters summarized. Reference is made to some developments on fiber and waveguide lasers. Relevant physical features of the silica fibres used for low-loss, long-band, optical transmission are reviewed, as well as present efforts to further reduce attenuation in the mid-infrared range. Particular attention is paid to photorefractive materials (LiNbO 3 , BGO, BSO, etc.), which are being investigated

  3. Super insulating aerogel glazing

    DEFF Research Database (Denmark)

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

    2004-01-01

    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......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...... of aerogel glazing will allow for a positive net energy gain even for north facing vertical windows in a Danish climate during the heating season. This means that high quality daylight can be obtained even with additional energy gain. On behalf of the partners of the two EU projects, results related...

  4. Insulated pipe clamp design

    International Nuclear Information System (INIS)

    Anderson, M.J.; Hyde, L.L.; Wagner, S.E.; Severud, L.K.

    1980-01-01

    Thin wall large diameter piping for breeder reactor plants can be subjected to significant thermal shocks during reactor scrams and other upset events. On the Fast Flux Test Facility, the addition of thick clamps directly on the piping was undesired because the differential metal temperatures between the pipe wall and the clamp could have significantly reduced the pipe thermal fatigue life cycle capabilities. Accordingly, an insulated pipe clamp design concept was developed. The design considerations and methods along with the development tests are presented. Special considerations to guard against adverse cracking of the insulation material, to maintain the clamp-pipe stiffness desired during a seismic event, to minimize clamp restraint on the pipe during normal pipe heatup, and to resist clamp rotation or spinning on the pipe are emphasized

  5. Insulated pipe clamp design

    International Nuclear Information System (INIS)

    Anderson, M.J.; Hyde, L.L.; Wagner, S.E.; Severud, L.K.

    1980-01-01

    Thin wall large diameter piping for breeder reactor plants can be subjected to significant thermal shocks during reactor scrams and other upset events. On the Fast Flux Test Facility, the addition of thick clamps directly on the piping was undesired because the differential metal temperatures between the pipe wall and the clamp could have significantly reduced the pipe thermal fatigue life cycle capabilities. Accordingly, an insulated pipe clamp design concept was developed. 5 refs

  6. Pourable Foam Insulation

    Science.gov (United States)

    Harvey, James A.; Butler, John M.; Chartoff, Richard P.

    1989-01-01

    Report describes search for polyisocyanurate/polyurethane foam insulation with superior characteristics. Discusses chemistry of current formulations. Tests of formulations, of individual ingredients and or alternative new formulations described. Search revealed commercially available formulations exhibiting increased thermal stability at temperatures up to 600 degree C, pours readily before curing, presents good appearance after curing, and remains securely bonded to aluminum at cryogenic temperatures. Total of 42 different formulations investigated, 10 found to meet requirements.

  7. Supporting Documentation for the 2008 Update to the Insulation Fact Sheet

    Energy Technology Data Exchange (ETDEWEB)

    Stovall, Therese K [ORNL

    2008-02-01

    The Insulation Fact Sheet provides consumers for general guidance and recommended insulation levels for their home. This fact sheet has been on-line since 1995 and this update addresses new insulation materials, as well as updated costs for energy and materials.

  8. Sustainable wall construction and exterior insulation retrofit technology process and structure

    Science.gov (United States)

    Vohra, Arun

    2000-01-01

    A low-cost process for exterior wall insulation retrofit, or new wall construction by stacking layers of fabric tube filled with insulating material against a wall and covering them with mesh and stucco provides a durable structure with good insulating value.

  9. Thermal insulation layer for the vacuum containers of a thermonuclear device

    International Nuclear Information System (INIS)

    Nishikawa, Masana; Yamada, Masao; Kameari, Akihisa; Niikura, Setsuo.

    1980-01-01

    Purpose: To prevent temperature rise of a thermal insulation layer for a vacuum container of a thermonuclear device higher than allowable value when irradiated by neutron by constructing the layer of a cooling unit in thermal insulation material. Constitution: A metal plate attached with cooling pipes is buried in a thermal insulation material forming a thermal insulation layer to form the layer provided between a vacuum container of a thermonuclear device and a shield. (Yoshihara, H.)

  10. Reduction of heat insulation upon soaking of the insulation layer

    Science.gov (United States)

    Achtliger, J.

    1983-09-01

    Improved thermal protection of hollow masonry by introduction of a core insulation between the inner and outer shell is discussed. The thermal conductivity of insulation materials was determined in dry state and after soaking by water with different volume-related moisture contents. The interpolated thermal conductivity values from three measured values at 10 C average temperature are presented as a function of the pertinent moisture content. Fills of expanded polystyrene, perlite and granulated mineral fibers, insulating boards made of mineral fibers and in situ cellular plastics produced from urea-formaldehyde resin were investigated. Test results show a confirmation of thermal conductivity values for insulating materials in hollow masonry.

  11. Electrical insulating liquid: A review

    Directory of Open Access Journals (Sweden)

    Deba Kumar Mahanta

    2017-08-01

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

  12. Concepts for evaluation of sound insulation of dwellings

    DEFF Research Database (Denmark)

    Rasmussen, Birgit; Rindel, Jens Holger

    2005-01-01

    Legal sound insulation requirements have existed more than 50 years in some countries, and single-number quantities for evaluation of sound insulation have existed nearly as long time. However, the concepts have changed considerably over time from simple arithmetic averaging of frequency bands......¬ments and classification schemes revealed significant differences of concepts. The paper summarizes the history of concepts, the disadvantages of the present chaos and the benefits of consensus concerning concepts for airborne and impact sound insulation between dwellings and airborne sound insulation of facades...... with a trend towards light-weight constructions are contradictory and challenging. This calls for exchange of data and experience, implying a need for harmonized concepts, including use of spectrum adaptation terms. The paper will provide input for future discussions in EAA TC-RBA WG4: "Sound insulation...

  13. Interfacial Coatings for Inorganic Composite Insulation Systems

    International Nuclear Information System (INIS)

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

    2006-01-01

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

  14. The Development and Application of Simulative Insulation Resistance Tester

    Science.gov (United States)

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

    2018-02-01

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

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

    Directory of Open Access Journals (Sweden)

    Michael E. Flatté

    2017-05-01

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

  16. Electrical resistivity study of insulators

    International Nuclear Information System (INIS)

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

    1998-01-01

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

  17. Cellulose insulation as an air barrier

    Energy Technology Data Exchange (ETDEWEB)

    Manning, K.

    1989-10-01

    The objective of this study was to determine if a wet sprayed cellulose wall insulation system would function satisfactorily without use of a polyethylene air/vapour barrier. The research was designed to demonstrate that this particular insulation system would form enough of a barrier to air leakage, that moisture accumulation from condensation and vapour diffusion would be insignificant. Field work conducted in Alberta, involved construction of a conventional duplex housing unit which was insulated with wet sprayed cellulose in the exterior walls and dry loose-fill cellulose in the attic areas. One half of the unit did not have a polyethylene air/vapor barrier installed. Air leakage and exterior wall moisture levels were monitored for a year following construction. Data collected during this time indicated that the moisture added to the walls during the insulating process was dissipated over the study period. The presence of polyethylene sheeting had no significant effect on the moisture levels in either the wall or attic areas of the test structure. On the other hand, testing indicated that the use of polyethylene sheeting in the wall system did serve to improve blower door air test results. In conclusion, although the air leakage resistance apparently provided by the polyethylene sheeting is significant, the amount is probably not more than could otherwise be obtained by more careful attention to sealing procedures such as those used in the airtight drywall technique. A more important finding is that the use of polyethylene sheeting is not essential in a structure which has the degree of air leakage resistance provided by the insulation system used in this project. 6 figs., 2 tabs.

  18. Cladding Attachment Over Thick Exterior Insulating Sheathing

    Energy Technology Data Exchange (ETDEWEB)

    Baker, P. [Building Science Corporation, Somerville, MA (United States); Eng, P. [Building Science Corporation, Somerville, MA (United States); Lepage, R. [Building Science Corporation, Somerville, MA (United States)

    2014-01-01

    The addition of insulation to the exterior of buildings is an effective means of increasing the thermal resistance of both wood framed walls as well as mass masonry wall assemblies. For thick layers of exterior insulation (levels greater than 1.5 inches), the use of wood furring strips attached through the insulation back to the structure has been used by many contractors and designers as a means to provide a convenient cladding attachment location (Straube and Smegal 2009, Pettit 2009, Joyce 2009, Ueno 2010). The research presented in this report is intended to help develop a better understanding of the system mechanics involved and the potential for environmental exposure induced movement between the furring strip and the framing. BSC sought to address the following research questions: 1. What are the relative roles of the mechanisms and the magnitudes of the force that influence the vertical displacement resistance of the system? 2. Can the capacity at a specified deflection be reliably calculated using mechanics based equations? 3. What are the impacts of environmental exposure on the vertical displacement of furring strips attached directly through insulation back to a wood structure?

  19. Magnetically self-insulated transformers

    International Nuclear Information System (INIS)

    Novac, B.M.; Smith, I.R.; Brown, J.

    2002-01-01

    Magnetic insulation is the only practicable form of insulation for much equipment used in ultrahigh pulsed-power work, including transmission lines and plasma opening switches. It has not however so far been successfully exploited in the transformers that are necessarily involved, and the first proposed design that appeared more than 30 years ago raised apparently insuperable problems. The two novel arrangements for a magnetically insulated transformer described in this paper overcome the problems faced by the earlier designs and also offer considerable scope for development in a number of important areas. Theoretical justification is given for their insulating properties, and this is confirmed by proof-of-principle results obtained from a small-scale experimental prototype in which magnetic insulation was demonstrated at up to 100 kV. (author)

  20. Excitons in insulators

    International Nuclear Information System (INIS)

    Grasser, R.; Scharmann, A.

    1983-01-01

    This chapter investigates absorption, reflectivity, and intrinsic luminescence spectra of free and/or self-trapped (localized) excitons in alkali halides and rare gas solids. Introduces the concepts underlying the Wannier-Mott and Frenkel exciton models, two extreme pictures of an exciton in crystalline materials. Discusses the theoretical and experimental background; excitons in alkali halides; and excitons in rare gas solids. Shows that the intrinsic optical behavior of wide gap insulators in the range of the fundamental absorption edge is controlled by modified Wannier-Mott excitons. Finds that while that alkali halides only show free and relaxed molecular-like exciton emission, in rare gas crystals luminescence due to free, single and double centered localized excitons is observed. Indicates that the simultaneous existence of free and self-trapped excitons in these solid requires an energy barrier for self-trapping

  1. Electronic structure and insulating gap in epitaxial VO2 polymorphs

    Directory of Open Access Journals (Sweden)

    Shinbuhm Lee

    2015-12-01

    Full Text Available Determining the origin of the insulating gap in the monoclinic V O2(M1 is a long-standing issue. The difficulty of this study arises from the simultaneous occurrence of structural and electronic transitions upon thermal cycling. Here, we compare the electronic structure of the M1 phase with that of single crystalline insulating V O2(A and V O2(B thin films to better understand the insulating phase of VO2. As these A and B phases do not undergo a structural transition upon thermal cycling, we comparatively study the origin of the gap opening in the insulating VO2 phases. By x-ray absorption and optical spectroscopy, we find that the shift of unoccupied t2g orbitals away from the Fermi level is a common feature, which plays an important role for the insulating behavior in VO2 polymorphs. The distinct splitting of the half-filled t2g orbital is observed only in the M1 phase, widening the bandgap up to ∼0.6 eV. Our approach of comparing all three insulating VO2 phases provides insight into a better understanding of the electronic structure and the origin of the insulating gap in VO2.

  2. Sound insulation design of modular construction housing

    OpenAIRE

    Yates, D. J.; Hughes, Lawrence; Campbell, A.

    2007-01-01

    This paper provides an insight into the acoustic issues of modular housing using the Verbus System of construction. The paper briefly summarises the history of the development of Verbus modular housing and the acoustic design considerations of the process. Results are presented from two sound insulation tests conducted during the course of the project. The results are discussed in terms of compliance with Approved Document E1 and increased performance standards such as EcoHomes2.

  3. Measure Guideline: Guidance on Taped Insulating Sheathing Drainage Planes

    Energy Technology Data Exchange (ETDEWEB)

    Grin, A. [Building Science Corporation, Somerville, MA (United States); Lstiburek, J. [Building Science Corporation, Somerville, MA (United States)

    2014-09-01

    The goal of this research is to provide durable and long-term water management solutions using exterior insulating sheathing as part of the water management system. It is possible to tape or seal the joints in insulating sheathing to create a drainage plane and even an air control layer. There exists the material durability component of the tape as well as the system durability component being the taped insulating sheathing as the drainage plane. This measure guideline provides best practice and product recommendations from the interviewed contractors and homebuilders who collectively have a vast amount of experience. Three significant issues were discussed with the group, which are required to make taped insulating sheathing a simple, long-term, and durable drainage plane: horizontal joints should be limited or eliminated wherever possible; where a horizontal joint exists use superior materials; and frequent installation inspection and regular trade training are required to maintain proper installation.

  4. 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.

  5. Measure Guideline: Wall Air Sealing and Insulation Methods in Existing Homes; An Overview of Opportunity and Process

    Energy Technology Data Exchange (ETDEWEB)

    Roberts, S.; Stephenson, R.

    2012-09-01

    This guide provides renovators and retrofit contractors an overview of considerations when including wall air sealing and insulation in an energy retrofit project. It also outlines the potential project risks, various materials for insulating, possible field inspections needed, installation procedures, as well as the benefits and drawbacks. The purpose of this document is to provide the outline of the overview and process of insulating and air sealing walls so that home retrofit professionals can identify approaches to air sealing and insulation measures.

  6. Lightweight, Thermally Insulating Structural Panels

    Science.gov (United States)

    Eisen, Howard J.; Hickey, Gregory; Wen, Liang-Chi; Layman, William E.; Rainen, Richard A.; Birur, Gajanana C.

    1996-01-01

    Lightweight, thermally insulating panels that also serve as structural members developed. Honeycomb-core panel filled with low-thermal-conductivity, opacified silica aerogel preventing convection and minimizes internal radiation. Copper coating on face sheets reduces radiation. Overall thermal conductivities of panels smaller than state-of-art commercial non-structurally-supporting foam and fibrous insulations. On Earth, panels suitable for use in low-air-pressure environments in which lightweight, compact, structurally supporting insulation needed; for example, aboard high-altitude aircraft or in partially evacuated panels in refrigerators.

  7. Reflecting variable opening insulating panel

    International Nuclear Information System (INIS)

    Nungesser, W.T.

    1976-01-01

    A description is given of a reflecting variable opening insulating panel assembly, comprising a static panel assembly of reflecting insulation sheets forming a cavity along one side of the panel and a movable panel opening out by sliding from the cavity of the static panel, and a locking device for holding the movable panel in a position extending from the cavity of the static panel. This can apply to a nuclear reactor of which the base might require maintenance and periodical checking and for which it is desirable to have available certain processes for the partial dismantling of the insulation [fr

  8. Wind Power Plant Grounding, Overvoltage Protection, and Insulation Coordination

    Energy Technology Data Exchange (ETDEWEB)

    Camm, E H [IEEE PES Wind Plant Collector System Design Working Group; Behnke, M. R. [IEEE PES Wind Plant Collector System Design Working Group; Bolado, O. [IEEE PES Wind Plant Collector System Design Working Group; Bollen, M. [IEEE PES Wind Plant Collector System Design Working Group; Bradt, M. [IEEE PES Wind Plant Collector System Design Working Group; Brooks, C. [IEEE PES Wind Plant Collector System Design Working Group; Dilling, W. [IEEE PES Wind Plant Collector System Design Working Group; Edds, M. [IEEE PES Wind Plant Collector System Design Working Group; Hejdak, W. J. [IEEE PES Wind Plant Collector System Design Working Group; Houseman, D. [IEEE PES Wind Plant Collector System Design Working Group; Klein, S. [IEEE PES Wind Plant Collector System Design Working Group; Li, Fangxing [ORNL; Li, J. [IEEE PES Wind Plant Collector System Design Working Group; Maibach, P. [IEEE PES Wind Plant Collector System Design Working Group; Nicolai, T. [IEEE PES Wind Plant Collector System Design Working Group; Pasupulati, S. V. [IEEE PES Wind Plant Collector System Design Working Group; Patino, J. [IEEE PES Wind Plant Collector System Design Working Group; Samaan, N. [IEEE PES Wind Plant Collector System Design Working Group; Saylors, S. [IEEE PES Wind Plant Collector System Design Working Group; Siebert, T. [IEEE PES Wind Plant Collector System Design Working Group; Smith, Travis M [ORNL; Starke, Michael R [ORNL; Walling, R. [IEEE PES Wind Plant Collector System Design Working Group

    2009-01-01

    Proper insulation coordination is critical to achieving expected life from wind plant equipment. The collector systems of large wind plants require the application of surge arresters to protect the equipment insulation from transient overvoltages. The application of surge arresters is constrained by maximum operating and temporary overvoltage levels. This paper provides a tutorial description of the process of selecting and applying surge arresters to wind plant medium voltage collector systems, with emphasis on the peculiar properties of this application.

  9. Optimizing inventory management in the insulation manufacturing industry

    OpenAIRE

    Herbert-Hansen, Zaza Nadja Lee; Larsen, Samuel

    2016-01-01

    Inventory issues within the insulation manufacturing industry are essential for competitiveness. However, they are largely unexplored in academic literature. Therefore the aim of this paper is to address the research question: “What approach to inventory management provides the best balance between service level and cost for the insulation manufacturing industry?” This is done through an in-depth case study of a world-leading company within this industry, with focus on two of its factories. T...

  10. High performance thermal insulation systems (HiPTI). Vacuum insulated products (VIP). Proceedings of the international conference and workshop

    Energy Technology Data Exchange (ETDEWEB)

    Zimmermann, M.; Bertschinger, H.

    2001-07-01

    These are the proceedings of the International Conference and Workshop held at EMPA Duebendorf, Switzerland, in January 2001. The papers presented at the conference's first day included contributions on the role of high-performance insulation in energy efficiency - providing an overview of available technologies and reviewing physical aspects of heat transfer and the development of thermal insulation as well as the state of the art of glazing technologies such as high-performance and vacuum glazing. Also, vacuum-insulated products (VIP) with fumed silica, applications of VIP systems in technical building systems, nanogels, VIP packaging materials and technologies, measurement of physical properties, VIP for advanced retrofit solutions for buildings and existing and future applications for advanced low energy building are discussed. Finally, research and development concerning VIP for buildings are reported on. The workshops held on the second day covered a preliminary study on high-performance thermal insulation materials with gastight porosity, flexible pipes with high performance thermal insulation, evaluation of modern insulation systems by simulation methods as well as the development of vacuum insulation panels with a stainless steel envelope.

  11. Repeatability of Cryogenic Multilayer Insulation

    Science.gov (United States)

    Johnson, W. L.; Vanderlaan, M.; Wood, J. J.; Rhys, N. O.; Guo, W.; Van Sciver, S.; Chato, D. J.

    2017-12-01

    Due to the variety of requirements across aerospace platforms, and one off projects, the repeatability of cryogenic multilayer insulation (MLI) has never been fully established. The objective of this test program is to provide a more basic understanding of the thermal performance repeatability of MLI systems that are applicable to large scale tanks. There are several different types of repeatability that can be accounted for: these include repeatability between identical blankets, repeatability of installation of the same blanket, and repeatability of a test apparatus. The focus of the work in this report is on the first two types of repeatability. Statistically, repeatability can mean many different things. In simplest form, it refers to the range of performance that a population exhibits and the average of the population. However, as more and more identical components are made (i.e. the population of concern grows), the simple range morphs into a standard deviation from an average performance. Initial repeatability testing on MLI blankets has been completed at Florida State University. Repeatability of five Glenn Research Center (GRC) provided coupons with 25 layers was shown to be +/- 8.4% whereas repeatability of repeatedly installing a single coupon was shown to be +/- 8.0%. A second group of 10 coupons has been fabricated by Yetispace and tested by Florida State University, the repeatability between coupons has been shown to be +/- 15-25%. Based on detailed statistical analysis, the data has been shown to be statistically significant.

  12. Molecular dewetting on insulators

    International Nuclear Information System (INIS)

    Burke, S A; Topple, J M; Gruetter, P

    2009-01-01

    Recent attention given to the growth and morphology of organic thin films with regard to organic electronics has led to the observation of dewetting (a transition from layer(s) to islands) of molecular deposits in many of these systems. Dewetting is a much studied phenomenon in the formation of polymer and liquid films, but its observation in thin films of the 'small' molecules typical of organic electronics requires additional consideration of the structure of the interface between the molecular film and the substrate. This review covers some key concepts related to dewetting and molecular film growth. In particular, the origins of different growth modes and the thickness dependent interactions which give rise to dewetting are discussed in terms of surface energies and the disjoining pressure. Characteristics of molecular systems which may lead to these conditions, including the formation of metastable interface structures and commensurate-incommensurate phase transitions, are also discussed. Brief descriptions of some experimental techniques which have been used to study molecular dewetting are given as well. Examples of molecule-on-insulator systems which undergo dewetting are described in some detail, specifically perylene derivatives on alkali halides, C 60 on alkali halides, and the technologically important system of pentacene on SiO 2 . These examples point to some possible predicting factors for the occurrence of dewetting, most importantly the formation of an interface layer which differs from the bulk crystal structure. (topical review)

  13. Molecular dewetting on insulators.

    Science.gov (United States)

    Burke, S A; Topple, J M; Grütter, P

    2009-10-21

    Recent attention given to the growth and morphology of organic thin films with regard to organic electronics has led to the observation of dewetting (a transition from layer(s) to islands) of molecular deposits in many of these systems. Dewetting is a much studied phenomenon in the formation of polymer and liquid films, but its observation in thin films of the 'small' molecules typical of organic electronics requires additional consideration of the structure of the interface between the molecular film and the substrate. This review covers some key concepts related to dewetting and molecular film growth. In particular, the origins of different growth modes and the thickness dependent interactions which give rise to dewetting are discussed in terms of surface energies and the disjoining pressure. Characteristics of molecular systems which may lead to these conditions, including the formation of metastable interface structures and commensurate-incommensurate phase transitions, are also discussed. Brief descriptions of some experimental techniques which have been used to study molecular dewetting are given as well. Examples of molecule-on-insulator systems which undergo dewetting are described in some detail, specifically perylene derivatives on alkali halides, C(60) on alkali halides, and the technologically important system of pentacene on SiO(2). These examples point to some possible predicting factors for the occurrence of dewetting, most importantly the formation of an interface layer which differs from the bulk crystal structure.

  14. Insulating fcc YH

    International Nuclear Information System (INIS)

    Molen, S. J. van der; Nagengast, D. G.; Gogh, A. T. M. van; Kalkman, J.; Kooij, E. S.; Rector, J. H.; Griessen, R.

    2001-01-01

    We study the structural, optical, and electrical properties of Mg z Y 1-z switchable mirrors upon hydrogenation. It is found that the alloys disproportionate into essentially pure YH 3-δ and MgH 2 with the crystal structure of YH 3-δ dependent on the Mg concentration z. For 0 3-δ are observed, whereas for z≥0.1 only cubic YH 3-δ is present. Interestingly, cubic YH 3-δ is expanded compared to YH 2 , in disagreement with theoretical predictions. From optical and electrical measurements we conclude that cubic YH 3-δ is a transparent insulator with properties similar to hexagonal YH 3-δ . Our results are inconsistent with calculations predicting fcc YH 3-δ to be metallic, but they are in good agreement with recent GW calculations on both hcp and fcc YH 3 . Finally, we find an increase in the effective band gap of the hydrided Mg z Y 1-z alloys with increasing z. Possibly this is due to quantum confinement effects in the small YH 3 clusters

  15. Topological Insulator Nanowires and Nanoribbons

    KAUST Repository

    Kong, Desheng; Randel, Jason C.; Peng, Hailin; Cha, Judy J.; Meister, Stefan; Lai, Keji; Chen, Yulin; Shen, Zhi-Xun; Manoharan, Hari C.; Cui, Yi

    2010-01-01

    Recent theoretical calculations and photoemission spectroscopy measurements on the bulk Bi2Se3 material show that it is a three-dimensional topological insulator possessing conductive surface states with nondegenerate spins, attractive

  16. 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.

  17. Metal-insulator-semiconductor photodetectors.

    Science.gov (United States)

    Lin, Chu-Hsuan; Liu, Chee Wee

    2010-01-01

    The major radiation of the sun can be roughly divided into three regions: ultraviolet, visible, and infrared light. Detection in these three regions is important to human beings. The metal-insulator-semiconductor photodetector, with a simpler process than the pn-junction photodetector and a lower dark current than the MSM photodetector, has been developed for light detection in these three regions. Ideal UV photodetectors with high UV-to-visible rejection ratio could be demonstrated with III-V metal-insulator-semiconductor UV photodetectors. The visible-light detection and near-infrared optical communications have been implemented with Si and Ge metal-insulator-semiconductor photodetectors. For mid- and long-wavelength infrared detection, metal-insulator-semiconductor SiGe/Si quantum dot infrared photodetectors have been developed, and the detection spectrum covers atmospheric transmission windows.

  18. Metal-Insulator-Semiconductor Photodetectors

    Directory of Open Access Journals (Sweden)

    Chu-Hsuan Lin

    2010-09-01

    Full Text Available The major radiation of the Sun can be roughly divided into three regions: ultraviolet, visible, and infrared light. Detection in these three regions is important to human beings. The metal-insulator-semiconductor photodetector, with a simpler process than the pn-junction photodetector and a lower dark current than the MSM photodetector, has been developed for light detection in these three regions. Ideal UV photodetectors with high UV-to-visible rejection ratio could be demonstrated with III-V metal-insulator-semiconductor UV photodetectors. The visible-light detection and near-infrared optical communications have been implemented with Si and Ge metal-insulator-semiconductor photodetectors. For mid- and long-wavelength infrared detection, metal-insulator-semiconductor SiGe/Si quantum dot infrared photodetectors have been developed, and the detection spectrum covers atmospheric transmission windows.

  19. Nuclear reactor insulation and preheat system

    International Nuclear Information System (INIS)

    Wampole, N.C.

    1978-01-01

    An insulation and preheat system is disclosed for preselected components of a fluid cooled nuclear reactor. A gas tight barrier or compartment of thermal insulation surrounds the selected components and includes devices to heat the internal atmosphere of the ocmpartment. An external surface of the compartment of enclosure is cooled, such as by a circulating fluid. The heating devices provide for preheating of the components, as well as maintenance of a temperature sufficient to ensure that the reactor coolant fluid will not solidify during shutdown. The external cooling limits the heat transferred to other plant structures, such as supporting concrete and steel. The barrier is spaced far enough from the surrounded components so as to allow access for remote or manual inspection, maintenance, and repair

  20. 16 CFR 460.18 - Insulation ads.

    Science.gov (United States)

    2010-01-01

    ... Commercial Practices FEDERAL TRADE COMMISSION TRADE REGULATION RULES LABELING AND ADVERTISING OF HOME INSULATION § 460.18 Insulation ads. (a) If your ad gives an R-value, you must give the type of insulation and... your ad gives a price, you must give the type of insulation, the R-value at a specific thickness, the...

  1. Metallic insulation transport and strainer clogging tests

    International Nuclear Information System (INIS)

    Hyvaerinen, J.; Hongisto, O.

    1994-06-01

    Experiments to probe the transport and clogging properties of metallic (metal reflective) insulation have been carried out in order to provide data for evaluation of their influence on the emergency core cooling and containment spray systems of the Finnish boiling water reactors in the event of a design basis accident. The specific metallic insulation tested was DARMET, provided by Darchem Engineering Ltd. The inner foils of Darmet are dimped. Available literature on the metallic insulation performance under design basis accident conditions has been reviewed. On the basis of the review a parametric approach has been chosen for the transport and clogging experiments. This approach involves testing a wide size range of various shapes of foil pieces. Five sets of experiments have been carried out. The first three sets investigate transport properties of the foil pieces, starting from sedimentation in stagnant waste pool and proceeding to transport in horizontal and vertically circulating flows. The clogging experiments have been addressed the differential pressures obtained due to accumulation of both pure and metallic and a mixture of metallic and fibrous (mineral wool) depris. (4 refs., 24 figs., 2 tabs.)

  2. Cryogenic foam insulation: Abstracted publications

    Science.gov (United States)

    Williamson, F. R.

    1977-01-01

    A group of documents were chosen and abstracted which contain information on the properties of foam materials and on the use of foams as thermal insulation at cryogenic temperatures. The properties include thermal properties, mechanical properties, and compatibility properties with oxygen and other cryogenic fluids. Uses of foams include applications as thermal insulation for spacecraft propellant tanks, and for liquefied natural gas storage tanks and pipelines.

  3. Superconductivity and ferromagnetism in topological insulators

    Science.gov (United States)

    Zhang, Duming

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

  4. External Insulation of Masonry Walls and Wood Framed Walls

    Energy Technology Data Exchange (ETDEWEB)

    Baker, P.

    2013-01-01

    The use of exterior insulation on a building is an accepted and effective means to increase the overall thermal resistance of the assembly that also has other advantages of improved water management and often increased air tightness of building assemblies. For thin layers of insulation (1" to 1 1/2"), the cladding can typically be attached directly through the insulation back to the structure. For thicker insulation layers, furring strips have been added as a cladding attachment location. This approach has been used in the past on numerous Building America test homes and communities (both new and retrofit applications), and has been proven to be an effective and durable means to provide cladding attachment. However, the lack of engineering data has been a problem for many designers, contractors, and code officials. This research project developed baseline engineering analysis to support the installation of thick layers of exterior insulation on existing masonry and frame walls. Furthermore, water management details necessary to integrate windows, doors, decks, balconies and roofs were created to provide guidance on the integration of exterior insulation strategies with other enclosure elements.

  5. External Insulation of Masonry Walls and Wood Framed Walls

    Energy Technology Data Exchange (ETDEWEB)

    Baker, P. [Building Science Corporation, Somerville, MA (United States)

    2013-01-01

    The use of exterior insulation on a building is an accepted and effective means to increase the overall thermal resistance of the assembly that also has other advantages of improved water management and often increased air tightness of building assemblies. For thin layers of insulation (1” to 1 ½”), the cladding can typically be attached directly through the insulation back to the structure. For thicker insulation layers, furring strips have been added as a cladding attachment location. This approach has been used in the past on numerous Building America test homes and communities (both new and retrofit applications), and has been proven to be an effective and durable means to provide cladding attachment. However, the lack of engineering data has been a problem for many designers, contractors, and code officials. This research project developed baseline engineering analysis to support the installation of thick layers of exterior insulation on existing masonry and frame walls. Furthermore, water management details necessary to integrate windows, doors, decks, balconies and roofs were created to provide guidance on the integration of exterior insulation strategies with other enclosure elements.

  6. Avalanches in insulating gases

    International Nuclear Information System (INIS)

    Verhaart, H.F.A.

    1982-01-01

    Avalanches of charged particles in gases are often studied with the ''electrical method'', the measurement of the waveform of the current in the external circuit. In this thesis a substantial improvement of the time resolution of the measuring setup, to be used for the electrical method, is reported. The avalanche is started by an N 2 -laser with a pulse duration of only 0.6 ns. With this laser it is possible to release a high number of primary electrons (some 10 8 ) which makes it possible to obtain sizeable signals, even at low E/p values. With the setup it is possible to analyze current waveforms with a time resolution down to 1.4 ns, determined by both the laser and the measuring system. Furthermore it is possible to distinguish between the current caused by the electrons and the current caused by the ions in the avalanche and to monitor these currents simultaneously. Avalanche currents are measured in N 2 , CO 2 , O 2 , H 2 O, air of varying humidity, SF 6 and SF 6 /N 2 mixtures. Depending on the nature of the gas and the experimental conditions, processes as diffusion, ionization, attachment, detachment, conversion and secondary emission are observed. Values of parameters with which these processes can be described, are derived from an analysis of the current waveforms. For this analysis already published theories and new theories described in this thesis are used. The drift velocity of both the electrons and the ions could be easily determined from measured avalanche currents. Special attention is paid to avalanches in air becasue of the practical importance of air insulation. (Auth.)

  7. 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.

  8. Electrical insulators for the theta-pinch fusion reactor

    International Nuclear Information System (INIS)

    Clinard, F.W. Jr.

    1976-01-01

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

  9. Insulator coated magnetic nanoparticulate composites with reduced core loss and method of manufacture thereof

    Science.gov (United States)

    Zhang, Yide (Inventor); Wang, Shihe (Inventor); Xiao, Danny (Inventor)

    2004-01-01

    A series of bulk-size magnetic/insulating nanostructured composite soft magnetic materials with significantly reduced core loss and its manufacturing technology. This insulator coated magnetic nanostructured composite is comprises a magnetic constituent, which contains one or more magnetic components, and an insulating constituent. The magnetic constituent is nanometer scale particles (1-100 nm) coated by a thin-layered insulating phase (continuous phase). While the intergrain interaction between the immediate neighboring magnetic nanoparticles separated by the insulating phase (or coupled nanoparticles) provide the desired soft magnetic properties, the insulating material provides the much demanded high resistivity which significantly reduces the eddy current loss. The resulting material is a high performance magnetic nanostructured composite with reduced core loss.

  10. Insulation system in an integrated motor compressor

    Energy Technology Data Exchange (ETDEWEB)

    Sihvo, V.

    2010-07-01

    A high-speed and high-voltage solid-rotor induction machine provides beneficial features for natural gas compressor technology. The mechanical robustness of the machine enables its use in an integrated motor-compressor. The technology uses a centrifugal compressor, which is mounted on the same shaft with the high-speed electrical machine driving it. No gearbox is needed as the speed is determined by the frequency converter. The cooling is provided by the process gas, which flows through the motor and is capable of transferring the heat away from the motor. The technology has been used in the compressors in the natural gas supply chain in the central Europe. New areas of application include natural gas compressors working at the wellheads of the subsea gas reservoir. A key challenge for the design of such a motor is the resistance of the stator insulation to the raw natural gas from the well. The gas contains water and heavy hydrocarbon compounds and it is far harsher than the sales gas in the natural gas supply network. The objective of this doctoral thesis is to discuss the resistance of the insulation to the raw natural gas and the phenomena degrading the insulation. The presence of partial discharges is analyzed in this doctoral dissertation. The breakdown voltage of the gas is measured as a function of pressure and gap distance. The partial discharge activity is measured on small samples representing the windings of the machine. The electrical field behavior is also modeled by finite element methods. Based on the measurements it has been concluded that the discharges are expected to disappear at gas pressures above 4 - 5 bar. The disappearance of discharges is caused by the breakdown strength of the gas, which increases as the pressure increases. Based on the finite element analysis, the physical length of a discharge seen in the PD measurements at atmospheric pressure was approximated to be 40 - 120 mum. The chemical aging of the insulation when exposed to raw

  11. Passive Collecting of Solar Radiation Energy using Transparent Thermal Insulators, Energetic Efficiency of Transparent Thermal Insulators

    Directory of Open Access Journals (Sweden)

    Smajo Sulejmanovic

    2014-11-01

    Full Text Available This paper explains passive collection of solar radiation energy using transparent thermal insulators. Transparent thermal insulators are transparent for sunlight, at the same time those are very good thermal insulators. Transparent thermal insulators can be placed instead of standard conventional thermal insulators and additionally transparent insulators can capture solar radiation, transform it into heat and save heat just as standard insulators. Using transparent insulators would lead to reduce in usage of fossil fuels and would help protection of an environment and reduce effects of global warming, etc.

  12. Cryogenic Insulation Standard Data and Methodologies Project

    Science.gov (United States)

    Summerfield, Burton; Thompson, Karen; Zeitlin, Nancy; Mullenix, Pamela; Fesmire, James; Swanger, Adam

    2015-01-01

    Extending some recent developments in the area of technical consensus standards for cryogenic thermal insulation systems, a preliminary Inter-Laboratory Study of foam insulation materials was performed by NASA Kennedy Space Center and LeTourneau University. The initial focus was ambient pressure cryogenic boil off testing using the Cryostat-400 flat-plate instrument. Completion of a test facility at LETU has enabled direct, comparative testing, using identical cryostat instruments and methods, and the production of standard thermal data sets for a number of materials under sub-ambient conditions. The two sets of measurements were analyzed and indicate there is reasonable agreement between the two laboratories. Based on cryogenic boiloff calorimetry, new equipment and methods for testing thermal insulation systems have been successfully developed. These boiloff instruments (or cryostats) include both flat plate and cylindrical models and are applicable to a wide range of different materials under a wide range of test conditions. Test measurements are generally made at large temperature difference (boundary temperatures of 293 K and 78 K are typical) and include the full vacuum pressure range. Results are generally reported in effective thermal conductivity (ke) and mean heat flux (q) through the insulation system. The new cryostat instruments provide an effective and reliable way to characterize the thermal performance of materials under subambient conditions. Proven in through thousands of tests of hundreds of material systems, they have supported a wide range of aerospace, industry, and research projects. Boiloff testing technology is not just for cryogenic testing but is a cost effective, field-representative methodology to test any material or system for applications at sub-ambient temperatures. This technology, when adequately coupled with a technical standards basis, can provide a cost-effective, field-representative methodology to test any material or system

  13. Positron Annihilation in Insulating Materials

    International Nuclear Information System (INIS)

    Asoka-Kumar, P; Sterne, PA

    2002-01-01

    We describe positron results from a wide range of insulating materials. We have completed positron experiments on a range of zeolite-y samples, KDP crystals, alkali halides and laser damaged SiO 2 . Present theoretical understanding of positron behavior in insulators is incomplete and our combined theoretical and experimental approach is aimed at developing a predictive understanding of positrons and positronium annihilation characteristics in insulators. Results from alkali halides and alkaline-earth halides show that positrons annihilate with only the halide ions, with no apparent contribution from the alkali or alkaline-earth cations. This contradicts the results of our existing theory for metals, which predicts roughly equal annihilation contributions from cation and anion. We also present result obtained using Munich positron microprobe on laser damaged SiO 2 samples

  14. Fermi surfaces in Kondo insulators

    Science.gov (United States)

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

    2018-04-01

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

  15. Reentrant Metal-Insulator Transitions in Silicon -

    Science.gov (United States)

    Campbell, John William M.

    This thesis describes a study of reentrant metal -insulator transitions observed in the inversion layer of extremely high mobility Si-MOSFETs. Magneto-transport measurements were carried out in the temperature range 20mK-4.2 K in a ^3He/^4 He dilution refrigerator which was surrounded by a 15 Tesla superconducting magnet. Below a melting temperature (T_{M}~500 mK) and a critical electron density (n_{s }~9times10^{10} cm^{-2}), the Shubnikov -de Haas oscillations in the diagonal resistivity enormous maximum values at the half filled Landau levels while maintaining deep minima corresponding to the quantum Hall effect at filled Landau levels. At even lower electron densities the insulating regions began to spread and eventually a metal-insulator transition could be induced at zero magnetic field. The measurement of extremely large resistances in the milliKelvin temperature range required the use of very low currents (typically in the 10^ {-12} A range) and in certain measurements minimizing the noise was also a consideration. The improvements achieved in these areas through the use of shielding, optical decouplers and battery operated instruments are described. The transport signatures of the insulating state are considered in terms of two basic mechanisms: single particle localization with transport by variable range hopping and the formation of a collective state such as a pinned Wigner crystal or electron solid with transport through the motion of bound dislocation pairs. The experimental data is best described by the latter model. Thus the two dimensional electron system in these high mobility Si-MOSFETs provides the first and only experimental demonstration to date of the formation of an electron solid at zero and low magnetic fields in the quantum limit where the Coulomb interaction energy dominates over the zero point oscillation energy. The role of disorder in favouring either single particle localization or the formation of a Wigner crystal is explored by

  16. Performance of antisolar insulated roof system

    Energy Technology Data Exchange (ETDEWEB)

    Ahmad, Irshad [Alternative Energy Development Board (AEDB), House No. 1, Main Nazimuddin Road, F-10/4, Islamabad (Pakistan)

    2010-01-15

    Rooms with concrete slab roofs directly exposed to the sun become unbearably hot during summer and very cold during winter. Huge amounts of energy are required to keep them comfortable. Application of thermal insulation on roofs significantly reduces energy required for heating and cooling. The effectiveness of roof insulations may be further enhanced if a layer of antisolar coating is applied on top of the insulation. The antisolar coating reflects most of the incident sunlight and prevents the roof from heating up. This reduces the daily cycles of thermal expansion and contraction which cause cracks in the roof slabs for the rainwater to leak through. The antisolar coating prolongs the useful life of the building structure as well as the life of the insulation that evaporates with heat. The method of application of the antisolar coating has been specially developed to eliminate thermal bridges formed between the edges of the tiles. This report presents the results of an experiment conducted at the Attock Refinery Limited (ARL) Rawalpindi to assess the performance of the antisolar insulated roof system. Record of the room temperature before and after the installation of the system shows a significant reduction in the indoor temperature. The room occupants, who used to experience a very high thermal stress after 10:30 am in spite of the 1.5-ton air conditioner operating in the room, felt much relieved after the installation. They had to turn back the thermostat of the air conditioner and even had to switch it off occasionally. A detailed thermal analysis of the room shows that cost of an antisolar system is paid back in less than a year in the form of savings of energy required for air-conditioning in summer and for gas heating in winter. In addition, the system prevents the addition of 150 kg per year of green house gases to the atmosphere for each square meter of the area covered by the system. It also provides a quieter environment by reducing the operational

  17. 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....

  18. An Insulating Glass Knowledge Base

    Energy Technology Data Exchange (ETDEWEB)

    Michael L. Doll; Gerald Hendrickson; Gerard Lagos; Russell Pylkki; Chris Christensen; Charlie Cureija

    2005-08-01

    This report will discuss issues relevant to Insulating Glass (IG) durability performance by presenting the observations and developed conclusions in a logical sequential format. This concluding effort discusses Phase II activities and focuses on beginning to quantifying IG durability issues while continuing the approach presented in the Phase I activities (Appendix 1) which discuss a qualitative assessment of durability issues. Phase II developed a focus around two specific IG design classes previously presented in Phase I of this project. The typical box spacer and thermoplastic spacer design including their Failure Modes and Effect Analysis (FMEA) and Fault Tree diagrams were chosen to address two currently used IG design options with varying components and failure modes. The system failures occur due to failures of components or their interfaces. Efforts to begin quantifying the durability issues focused on the development and delivery of an included computer based IG durability simulation program. The focus/effort to deliver the foundation for a comprehensive IG durability simulation tool is necessary to address advancements needed to meet current and future building envelope energy performance goals. This need is based upon the current lack of IG field failure data and the lengthy field observation time necessary for this data collection. Ultimately, the simulation program is intended to be used by designers throughout the current and future industry supply chain. Its use is intended to advance IG durability as expectations grow around energy conservation and with the growth of embedded technologies as required to meet energy needs. In addition the tool has the immediate benefit of providing insight for research and improvement prioritization. Included in the simulation model presentation are elements and/or methods to address IG materials, design, process, quality, induced stress (environmental and other factors), validation, etc. In addition, acquired data

  19. Propagation Characteristics of Multilayer Hybrid Insulator-Metal-Insulator and Metal-Insulator-Metal Plasmonic Waveguides

    Directory of Open Access Journals (Sweden)

    M. Talafi Noghani

    2014-02-01

    Full Text Available Propagation characteristics of symmetrical and asymmetrical multilayer hybrid insulator-metal-insulator (HIMI and metal-insulator-metal (HMIM plasmonic slab waveguides are investigated using the transfer matrix method. Propagation length (Lp and spatial length (Ls are used as two figures of merit to qualitate the plasmonic waveguides. Symmetrical structures are shown to be more performant (having higher Lp and lower Ls, nevertheless it is shown that usage of asymmetrical geometry could compensate for the performance degradation in practically realized HIMI waveguides with different substrate materials. It is found that HMIM slab waveguide could support almost long-range subdiffraction plasmonic modes at dimensions lower than the spatial length of the HIMI slab waveguide.

  20. Improved installation approach for variable spring setting on a pipe yet to be insulated

    International Nuclear Information System (INIS)

    Shah, H.H.; Chitnis, S.S.; Rencher, D.

    1993-01-01

    This paper provides an approach in setting of variable spring supports for noninsulated or partially insulated piping systems so that resetting these supports is not required when the insulation is fully installed. This approach shows a method of deriving the spring coldload setting tolerance values that can be readily utilized by craft personnel. This method is based on the percentage of the weight of the insulation compared to the total weight of the pipe and the applicable tolerance. Use of these setting tolerances eliminates reverification of the original cold-load settings, for the majority of variable springs when the insulation is fully installed

  1. Electrical insulation for large multiaxis superconducting magnets

    International Nuclear Information System (INIS)

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

    1975-01-01

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

  2. Emerging Trends in Topological Insulators and Topological ...

    Indian Academy of Sciences (India)

    /fulltext/reso/022/08/0787-0800. Keywords. Superconductor, quantum Hall effect, topological insulator, Majorana fermions. Abstract. Topological insulators are new class of materials which arecharacterized by a bulk band gap like ordinary ...

  3. A protocol for lifetime energy and environmental impact assessment of building insulation materials

    International Nuclear Information System (INIS)

    Shrestha, Som S.; Biswas, Kaushik; Desjarlais, Andre O.

    2014-01-01

    This article describes a proposed protocol that is intended to provide a comprehensive list of factors to be considered in evaluating the direct and indirect environmental impacts of building insulation materials, as well as detailed descriptions of standardized calculation methodologies to determine those impacts. The energy and environmental impacts of insulation materials can generally be divided into two categories: (1) direct impact due to the embodied energy of the insulation materials and other factors and (2) indirect or environmental impacts avoided as a result of reduced building energy use due to addition of insulation. Standards and product category rules exist, which provide guidelines about the life cycle assessment (LCA) of materials, including building insulation products. However, critical reviews have suggested that these standards fail to provide complete guidance to LCA studies and suffer from ambiguities regarding the determination of the environmental impacts of building insulation and other products. The focus of the assessment protocol described here is to identify all factors that contribute to the total energy and environmental impacts of different building insulation products and, more importantly, provide standardized determination methods that will allow comparison of different insulation material types. Further, the intent is not to replace current LCA standards but to provide a well-defined, easy-to-use comparison method for insulation materials using existing LCA guidelines. - Highlights: • We proposed a protocol to evaluate the environmental impacts of insulation materials. • The protocol considers all life cycle stages of an insulation material. • Both the direct environmental impacts and the indirect impacts are defined. • Standardized calculation methods for the ‘avoided operational energy’ is defined. • Standardized calculation methods for the ‘avoided environmental impact’ is defined

  4. Vacuum-insulated catalytic converter

    Science.gov (United States)

    Benson, David K.

    2001-01-01

    A catalytic converter has an inner canister that contains catalyst-coated substrates and an outer canister that encloses an annular, variable vacuum insulation chamber surrounding the inner canister. An annular tank containing phase-change material for heat storage and release is positioned in the variable vacuum insulation chamber a distance spaced part from the inner canister. A reversible hydrogen getter in the variable vacuum insulation chamber, preferably on a surface of the heat storage tank, releases hydrogen into the variable vacuum insulation chamber to conduct heat when the phase-change material is hot and absorbs the hydrogen to limit heat transfer to radiation when the phase-change material is cool. A porous zeolite trap in the inner canister absorbs and retains hydrocarbons from the exhaust gases when the catalyst-coated substrates and zeolite trap are cold and releases the hydrocarbons for reaction on the catalyst-coated substrate when the zeolite trap and catalyst-coated substrate get hot.

  5. On effective holographic Mott insulators

    Energy Technology Data Exchange (ETDEWEB)

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

    2016-12-20

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

  6. On effective holographic Mott insulators

    International Nuclear Information System (INIS)

    Baggioli, Matteo; Pujolàs, Oriol

    2016-01-01

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

  7. Thermal insulation of fuel elements

    International Nuclear Information System (INIS)

    Dubrovcak, P.; Pec, V.; Pitonak, J.

    1978-01-01

    The claim of the invention concerns thermal insulation of fuel elements heated for measurement of uranium fuel physical properties. For this, layers of aluminium film and of glass fibre are wound onto the inner tube of the element cladding. The space between the inner and the outer tubes is evacuated and the tubes are spaced using spacer wires. (M.S.)

  8. Forming Refractory Insulation On Copper Wire

    Science.gov (United States)

    Setlock, J.; Roberts, G.

    1995-01-01

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

  9. Optimization design for SST-1 Tokamak insulators

    International Nuclear Information System (INIS)

    Zhang Yuanbin; Pan Wanjiang

    2012-01-01

    With the help of ANSYS FEA technique, high voltage and cryogenic proper- ties of the SST-1 Tokamak insulators were obtained, and the structure of the insulators was designed and modified by taking into account the simulation results. The simulation results indicate that the optimization structure has better high voltage insulating property and cryogenic mechanics property, and also can fulfill the qualification criteria of the SST-1 Tokamak insulators. (authors)

  10. Insulator applications in a Tokamak reactor

    International Nuclear Information System (INIS)

    Leger, D.

    1986-06-01

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

  11. 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

  12. Effects of insulating vanadium oxide composite in concomitant mixed phases via interface barrier modulations on the performance improvements in metal-insulator-metal diodes

    Directory of Open Access Journals (Sweden)

    Kaleem Abbas

    2018-03-01

    Full Text Available The performance of metal-insulator-metal diodes is investigated for insulating vanadium oxide (VOx composite composed of concomitant mixed phases using the Pt metal as the top and the bottom electrodes. Insulating VOx composite in the Pt/VOx/Pt diode exhibits a high asymmetry of 10 and a very high sensitivity of 2,135V−1 at 0.6 V. The VOx composite provides Schottky-like barriers at the interface, which controls the current flow and the trap-assisted conduction mechanism. Such dramatic enhancement in asymmetry and rectification performance at low applied bias may be ascribed to the dynamic control of the insulating and metallic phases in VOx composites. We find that the nanostructure details of the insulating VOx layer can be critical in enhancing the performance of MIM diodes.

  13. Measure Guideline: Installing Rigid Foam Insulation on the Interior of Existing Brick Walls

    Energy Technology Data Exchange (ETDEWEB)

    Natarajan, H.; Klocke, S.; Puttagunta, S.

    2012-06-01

    This measure guideline provides information on an effective method to insulate the interior of existing brick masonry walls with extruded polystyrene (XPS) insulation board. The guide outlines step-by-step design and installation procedures while explaining the benefits and tradeoffs where applicable. The authors intend that this document be useful to a varied audience that includes builders, remodelers, contractors and homeowners.

  14. Measure Guideline. Installing Rigid Foam Insulation on the Interior of Existing Brick Walls

    Energy Technology Data Exchange (ETDEWEB)

    Natarajan, Hariharan [Consortium for Advanced Residential Buildings (CARB), Norwalk, CT (United States); Klocke, Steve [Consortium for Advanced Residential Buildings (CARB), Norwalk, CT (United States); Puttagunta, Srikanth [Consortium for Advanced Residential Buildings (CARB), Norwalk, CT (United States)

    2012-06-01

    This measure guideline provides information on an effective method to insulate the interior of existing brick masonry walls with extruded polystyrene (XPS) insulation board. The guide outlines step-by-step design and installation procedures while explaining the benefits and tradeoffs where applicable. The authors intend that this document be useful to a varied audience that includes builders,remodelers, contractors and homeowners.

  15. State of the art on historic building insulation materials and retrofit strategies

    DEFF Research Database (Denmark)

    Blumberga, Andra; Kass, Kristaps; Kamendere, Edite

    2016-01-01

    This report provides an analysis and evaluation of a state-of-the-art of internal insulation materials and methods for application in historic buildings, and review on methods, tools and guidelines used as decision making tools for implementation of internal insulation in historic buildings. Hist...

  16. Dielectric and Insulating Technology 2005 : Reviews & Forecasts

    Science.gov (United States)

    Okamoto, Tatsuki

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

  17. Dielectric and Insulating Technology 2006 : Review & Forecast

    Science.gov (United States)

    Okamoto, Tatsuki

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

  18. Wide gap Chern Mott insulating phases achieved by design

    Science.gov (United States)

    Guo, Hongli; Gangopadhyay, Shruba; Köksal, Okan; Pentcheva, Rossitza; Pickett, Warren E.

    2017-12-01

    Quantum anomalous Hall insulators, which display robust boundary charge and spin currents categorized in terms of a bulk topological invariant known as the Chern number (Thouless et al Phys. Rev. Lett. 49, 405-408 (1982)), provide the quantum Hall anomalous effect without an applied magnetic field. Chern insulators are attracting interest both as a novel electronic phase and for their novel and potentially useful boundary charge and spin currents. Honeycomb lattice systems such as we discuss here, occupied by heavy transition-metal ions, have been proposed as Chern insulators, but finding a concrete example has been challenging due to an assortment of broken symmetry phases that thwart the topological character. Building on accumulated knowledge of the behavior of the 3d series, we tune spin-orbit and interaction strength together with strain to design two Chern insulator systems with bandgaps up to 130 meV and Chern numbers C = -1 and C = 2. We find, in this class, that a trade-off between larger spin-orbit coupling and strong interactions leads to a larger gap, whereas the stronger spin-orbit coupling correlates with the larger magnitude of the Hall conductivity. Symmetry lowering in the course of structural relaxation hampers obtaining quantum anomalous Hall character, as pointed out previously; there is only mild structural symmetry breaking of the bilayer in these robust Chern phases. Recent growth of insulating, magnetic phases in closely related materials with this orientation supports the likelihood that synthesis and exploitation will follow.

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

    Science.gov (United States)

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

    2018-03-01

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

  20. Transport and screen blockage characteristics of reflective metallic insulation materials

    International Nuclear Information System (INIS)

    Brocard, D.N.

    1984-01-01

    In the event of a LOCA within a nuclear power plant, it is possible for insulation debris to be generated by the break jet. Such debris has the potential for PWR sump screen (or BWR RHR suction inlet) blockage and thus can affect the long-term recirculation capability. In addition to the variables of break jet location and orientation, the types and quantities of debris which could be generated are dependent on the insulation materials employed. This experimental investigation was limited to reflective metallic insulation and components thereof. The study was aimed at determining the flow velocities needed to transport the insulation debris to the sump screens and the resulting modes of screen blockage. The tests revealed that thin metallic foils (0.0025 in. and 0.004 in.) could transport at low flow velocities, 0.2 to 0.5 ft/sec. Thicker foils (0.008 in.) transported at higher velocities, 0.4 to 0.8 ft/sec, and as fabricated half cylinder insulation units required velocities in excess of 1.0 ft/sec for transport. The tests also provided information on screen blockage patterns that showed blockage could occur at the lower portion of the screen as foils readily flipped on the screen when reaching it

  1. Thin Aerogel as a Spacer in Multilayer Insulation

    Science.gov (United States)

    Moroz, Nancy

    2015-01-01

    Cryogenic fluid management is a critical technical area that is needed for future space exploration. A key challenge is the storability of liquid hydrogen (LH2), liquid methane (LCH4), and liquid oxygen (LOX) propellants for long-duration missions. The storage tanks must be well-insulated to prevent over-pressurization and venting, which can lead to unacceptable propellant losses for long-duration missions to Mars and beyond. Aspen Aerogels had validated the key process step to enable the fabrication of thin, low-density aerogel materials. The multilayer aerogel insulation (MLAI) system prototypes were prepared using sheets of aerogel materials with superior thermal performance exceeding current state-of-the-art insulation for space applications. The exceptional properties of this system include a new breakthrough in high-vacuum cryogenic thermal insulation, providing a durable material with excellent thermal performance at a reduced cost when compared to longstanding state-of-the-art multilayer insulation systems. During the Phase II project, further refinement and qualification/system-level testing of the MLAI system will be performed for use in cryogenic storage applications. Aspen has been in discussions with United Launch Alliance, LLC; NASA's Kennedy Space Center; and Yetispace, Inc., to test the MLAI system on rea-lworld tanks such as Vibro-Acoustic Test Article (VATA) or the Cryogenic Orbital Testbed (CRYOTE).

  2. Spin-torque generation in topological insulator based heterostructures

    KAUST Repository

    Fischer, Mark H.

    2016-03-11

    Heterostructures utilizing topological insulators exhibit a remarkable spin-torque efficiency. However, the exact origin of the strong torque, in particular whether it stems from the spin-momentum locking of the topological surface states or rather from spin-Hall physics of the topological-insulator bulk, remains unclear. Here, we explore a mechanism of spin-torque generation purely based on the topological surface states. We consider topological-insulator-based bilayers involving ferromagnetic metal (TI/FM) and magnetically doped topological insulators (TI/mdTI), respectively. By ascribing the key theoretical differences between the two setups to location and number of active surface states, we describe both setups within the same framework of spin diffusion of the nonequilibrium spin density of the topological surface states. For the TI/FM bilayer, we find large spin-torque efficiencies of roughly equal magnitude for both in-plane and out-of-plane spin torques. For the TI/mdTI bilayer, we elucidate the dominance of the spin-transfer-like torque. However, we cannot explain the orders of magnitude enhancement reported. Nevertheless, our model gives an intuitive picture of spin-torque generation in topological-insulator-based bilayers and provides theoretical constraints on spin-torque generation due to topological surface states.

  3. Optimizing inventory management in the insulation manufacturing industry

    DEFF Research Database (Denmark)

    Herbert-Hansen, Zaza Nadja Lee; Larsen, Samuel

    2016-01-01

    Inventory issues within the insulation manufacturing industry are essential for competitiveness. However, they are largely unexplored in academic literature. Therefore the aim of this paper is to address the research question: “What approach to inventory management provides the best balance between...... service level and cost for the insulation manufacturing industry?” This is done through an in-depth case study of a world-leading company within this industry, with focus on two of its factories. This paper contributes with empirical research within operations management in a sector which has not been...

  4. Conformally encapsulated multi-electrode arrays with seamless insulation

    Energy Technology Data Exchange (ETDEWEB)

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

    2016-11-22

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

  5. PRODUCTION OF AN INSULATION MATERIAL FROM CARPET AND BORON WASTES

    Directory of Open Access Journals (Sweden)

    Yasin ERDOĞAN

    2016-12-01

    Full Text Available Buildings are large consumers of energy in all countries. In regions with harsh climatic conditions, a substantial share of energy goes to heat and cool buildings. This paper reports an investigation of the insulation materials made from mixing carpet wastes with a solution with added crude colemanite ore, one of boron minerals, and a solution with added colemanite wastes from a barrage. A new building insulation material was produced which is name, Halibor. Optimum mixing ratios were determined for mass production and the physical properties of the product were established. In addition, the material produced was compared with similar products used in buildings in terms of physical properties. As a result of the investigations, it was established that the product provides high heat and sound insulation and can be used easily in building and construction industry.

  6. Certificateless Key-Insulated Generalized Signcryption Scheme without Bilinear Pairings

    Directory of Open Access Journals (Sweden)

    Caixue Zhou

    2017-01-01

    Full Text Available Generalized signcryption (GSC can be applied as an encryption scheme, a signature scheme, or a signcryption scheme with only one algorithm and one key pair. A key-insulated mechanism can resolve the private key exposure problem. To ensure the security of cloud storage, we introduce the key-insulated mechanism into GSC and propose a concrete scheme without bilinear pairings in the certificateless cryptosystem setting. We provide a formal definition and a security model of certificateless key-insulated GSC. Then, we prove that our scheme is confidential under the computational Diffie-Hellman (CDH assumption and unforgeable under the elliptic curve discrete logarithm (EC-DL assumption. Our scheme also supports both random-access key update and secure key update. Finally, we evaluate the efficiency of our scheme and demonstrate that it is highly efficient. Thus, our scheme is more suitable for users who communicate with the cloud using mobile devices.

  7. Quantum fluctuations in insulating ferroelectrics

    International Nuclear Information System (INIS)

    Riseborough, Peter S.

    2010-01-01

    Graphical abstract: It has been proposed that in a ferroelectric insulator, an applied magnetic field may couple the transverse phonon modes and produce left and right circularly polarized phonon modes which are no longer degenerate. We quantize the theory and examine the effects of quantal fluctuations. In particular, we show that the zero point fluctuations result in a large diamagnetic contribution to the magnetic susceptibility. - Abstract: It has been proposed that in a ferroelectric insulator, an applied magnetic field may couple the transverse phonon modes and produce left and right circularly polarized phonon modes which are no longer degenerate. We quantize the theory and examine the effects of quantal fluctuations. In particular, we show that the zero-point fluctuations result in a large diamagnetic contribution to the magnetic susceptibility.

  8. Multilayer Insulation Ascent Venting Model

    Science.gov (United States)

    Tramel, R. W.; Sutherlin, S. G.; Johnson, W. L.

    2017-01-01

    The thermal and venting transient experienced by tank-applied multilayer insulation (MLI) in the Earth-to-orbit environment is very dynamic and not well characterized. This new predictive code is a first principles-based engineering model which tracks the time history of the mass and temperature (internal energy) of the gas in each MLI layer. A continuum-based model is used for early portions of the trajectory while a kinetic theory-based model is used for the later portions of the trajectory, and the models are blended based on a reference mean free path. This new capability should improve understanding of the Earth-to-orbit transient and enable better insulation system designs for in-space cryogenic propellant systems.

  9. Chiral topological insulator of magnons

    Science.gov (United States)

    Li, Bo; Kovalev, Alexey A.

    2018-05-01

    We propose a magnon realization of 3D topological insulator in the AIII (chiral symmetry) topological class. The topological magnon gap opens due to the presence of Dzyaloshinskii-Moriya interactions. The existence of the topological invariant is established by calculating the bulk winding number of the system. Within our model, the surface magnon Dirac cone is protected by the sublattice chiral symmetry. By analyzing the magnon surface modes, we confirm that the backscattering is prohibited. By weakly breaking the chiral symmetry, we observe the magnon Hall response on the surface due to opening of the gap. Finally, we show that by changing certain parameters, the system can be tuned between the chiral topological insulator, three-dimensional magnon anomalous Hall, and Weyl magnon phases.

  10. Magnetically insulated transmission line oscillator

    Science.gov (United States)

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

    1987-05-19

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

  11. Secondary electron emission from insulators

    International Nuclear Information System (INIS)

    Kanaya, K.; Ono, S.; Ishigaki, F.

    1978-01-01

    The high yield of secondary electron emission from insulators due to electron bombardment may be the result of an increase of the depth of escape. The free-electron scattering theory is applied to the high energy of primary beams, but cannot be applied to the low energy of secondary escaping beams because of the large energy gap of the insulators. The plasmon loss with the valence electron is considered when the secondary electrons escape. Based on the energy retardation power formula of the penetration and energy loss of an electron probe into solid targets, secondary electron emissions from insulators are calculated from the assumptions that the distribution of the secondary electrons due to both incident and back-scattered electrons within the target is isotropic and that it follows the absorption law of the Lenard type. The universal yield-energy curve of the secondary electron emission, which is deduced as a function of three parameters such as ionisation potential, valence electron and the back-scattered coefficient in addition to the free-electron density effect, is found to be in good agreement with the experimental results. (author)

  12. Standard Practice for Evaluating Thermal Insulation Materials for Use in Solar Collectors

    CERN Document Server

    American Society for Testing and Materials. Philadelphia

    1994-01-01

    1.1 This practice sets forth a testing methodology for evaluating the properties of thermal insulation materials to be used in solar collectors with concentration ratios of less than 10. Tests are given herein to evaluate the pH, surface burning characteristics, moisture adsorption, water absorption, thermal resistance, linear shrinkage (or expansion), hot surface performance, and accelerated aging. This practice provides a test for surface burning characteristics but does not provide a methodology for determining combustibility performance of thermal insulation materials. 1.2 The tests shall apply to blanket, rigid board, loose-fill, and foam thermal insulation materials used in solar collectors. Other thermal insulation materials shall be tested in accordance with the provisions set forth herein and should not be excluded from consideration. 1.3 The assumption is made that elevated temperature, moisture, and applied stresses are the primary factors contributing to the degradation of thermal insulation mat...

  13. Topological Oxide Insulator in Cubic Perovskite Structure

    Science.gov (United States)

    Jin, Hosub; Rhim, Sonny H.; Im, Jino; Freeman, Arthur J.

    2013-01-01

    The emergence of topologically protected conducting states with the chiral spin texture is the most prominent feature at the surface of topological insulators. On the application side, large band gap and high resistivity to distinguish surface from bulk degrees of freedom should be guaranteed for the full usage of the surface states. Here, we suggest that the oxide cubic perovskite YBiO3, more than just an oxide, defines itself as a new three-dimensional topological insulator exhibiting both a large bulk band gap and a high resistivity. Based on first-principles calculations varying the spin-orbit coupling strength, the non-trivial band topology of YBiO3 is investigated, where the spin-orbit coupling of the Bi 6p orbital plays a crucial role. Taking the exquisite synthesis techniques in oxide electronics into account, YBiO3 can also be used to provide various interface configurations hosting exotic topological phenomena combined with other quantum phases. PMID:23575973

  14. Effects of insulation on potted superconducting coils

    International Nuclear Information System (INIS)

    Zeller, A.F.; DeKamp, J.C.; Magsig, C.T.; Nolen, J.A.; McInturff, A.D.

    1989-01-01

    Test coils using identical wire but with either Formvar or Polyesterimid insulation were fabricated to determine the effects of insulation on training behavior. It was found that the type of insulation did not affect the training behavior. While considerable attention has been paid to epoxy formulations used for superconducting coils, little study has been devoted to the effects of the wire insulation on training behavior. If the insulation does not bind well with the epoxy, the wires will not be held securely in place, and training will be required to make the coil operate at its design limit. In fact, the coil may never reach its design current, showing considerable degredation. Conversely, if the epoxy-insulation reaction is to soften or weaken the insulation, then shorts and/or training may result. The authors have undertaken a study of the effects of the insulation on potted coils wet wound with Stycast 2850 FT epoxy. The wire was insulated with one of two insulting varnishes: Formvar (a polyvinyl formal resin) or Polyesterimid (a phenolic resin). Formvar is the standard insulation in the United States while Polyesterimid the European standard

  15. Insulator-insulator and insulator-conductor transitions in the phase diagram of aluminium trichloride

    Directory of Open Access Journals (Sweden)

    Romina Ruberto

    2009-01-01

    Full Text Available We report a classical computer-simulation study of the phase diagram of AlCl3 in the pressure-temperature (p, T plane, showing (i that melting from a layered crystal structure occurs into a molecular liquid at low (p, T and into a dissociated ionic liquid at high (p, T, and (ii that a broad transition from a molecular insulator to an ionic conductor takes place in the liquid state.

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

    Science.gov (United States)

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

    2013-01-01

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

  17. The Structural Heat Intercept-Insulation-Vibration Evaluation Rig (SHIVER)

    Science.gov (United States)

    Johnson, W. L.; Zoeckler, J. G.; Best-Ameen, L. M.

    2015-01-01

    NASA is currently investigating methods to reduce the boil-off rate on large cryogenic upper stages. Two such methods to reduce the total heat load on existing upper stages are vapor cooling of the cryogenic tank support structure and integration of thick multilayer insulation systems to the upper stage of a launch vehicle. Previous efforts have flown a 2-layer MLI blanket and shown an improved thermal performance, and other efforts have ground-tested blankets up to 70 layers thick on tanks with diameters between 2 3 meters. However, thick multilayer insulation installation and testing in both thermal and structural modes has not been completed on a large scale tank. Similarly, multiple vapor cooled shields are common place on science payload helium dewars; however, minimal effort has gone into intercepting heat on large structural surfaces associated with rocket stages. A majority of the vapor cooling effort focuses on metallic cylinders called skirts, which are the most common structural components for launch vehicles. In order to provide test data for comparison with analytical models, a representative test tank is currently being designed to include skirt structural systems with integral vapor cooling. The tank is 4 m in diameter and 6.8 m tall to contain 5000 kg of liquid hydrogen. A multilayer insulation system will be designed to insulate the tank and structure while being installed in a representative manner that can be extended to tanks up to 10 meters in diameter. In order to prove that the insulation system and vapor cooling attachment methods are structurally sound, acoustic testing will also be performed on the system. The test tank with insulation and vapor cooled shield installed will be tested thermally in the B2 test facility at NASAs Plumbrook Station both before and after being vibration tested at Plumbrooks Space Power Facility.

  18. Insulation Progress since the Mid-1950s

    Science.gov (United States)

    Timmerhaus, K. D.

    Storage vessel and cryostat design for modern cryogenic systems has become rather routine as the result of the wide use of and application of cryogenic fluids. Such vessels for these fluids range in size from 1 L flasks used in the laboratory for liquid nitrogen to the more than 200,000 m3 double-walled tanks used for temporary storage of liquefied natural gas before being transported overseas to their final destination. These storage vessels for cryogenic fluids range in type from low-performance containers insulated with rigid foam or fibrous insulation to high-performance containers insulated with evacuated multilayer insulations. The overriding factors in the type of container selected normally are of economics and safety. This paper will consider various insulation concepts used in such cryogenic storage systems and will review the progress that has been made over the past 50 years in these insulation systems.

  19. Handleable shapes of thermal insulation material

    Energy Technology Data Exchange (ETDEWEB)

    Hughes, J. T.

    1989-01-17

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

  20. Hydrogen storage in insulated pressure vessels

    Energy Technology Data Exchange (ETDEWEB)

    Aceves, S.M.; Garcia-Villazana, O. [Lawrence Livermore National Lab., CA (United States)

    1998-08-01

    Insulated pressure vessels are cryogenic-capable pressure vessels that can be fueled with liquid hydrogen (LH{sub 2}) or ambient-temperature compressed hydrogen (CH{sub 2}). Insulated pressure vessels offer the advantages of liquid hydrogen tanks (low weight and volume), with reduced disadvantages (lower energy requirement for hydrogen liquefaction and reduced evaporative losses). This paper shows an evaluation of the applicability of the insulated pressure vessels for light-duty vehicles. The paper shows an evaluation of evaporative losses and insulation requirements and a description of the current analysis and experimental plans for testing insulated pressure vessels. The results show significant advantages to the use of insulated pressure vessels for light-duty vehicles.

  1. ASRM case insulation design and development

    Science.gov (United States)

    Bell, Matthew S.; Tam, William F. S.

    1992-10-01

    This paper describes the achievements made on the Advanced Solid Rocket Motor (ASRM) case insulation design and development program. The ASRM case insulation system described herein protects the metal case and joints from direct radiation and hot gas impingement. Critical failure of solid rocket systems is often traceable to failure of the insulation design. The wide ranging accomplishments included the development of a nonasbestos insulation material for ASRM that replaced the existing Redesigned Solid Rocket Motor (RSRM) asbestos-filled nitrile butadiene rubber (NBR) along with a performance gain of 300 pounds, and improved reliability of all the insulation joint designs, i.e., segmented case joint, case-to-nozzle and case-to-igniter joint. The insulation process development program included the internal stripwinding process. This process advancement allowed Aerojet to match to exceed the capability of other propulsion companies.

  2. Prediction of breakdown voltages in novel gases for high voltage insulation

    Energy Technology Data Exchange (ETDEWEB)

    Koch, M.

    2015-07-01

    This thesis submitted to the Swiss Federal Institute of Technology ETH in Zurich examines the use of sulphur hexafluoride (SF{sub 6}) and similar gases as important insulation media for high voltage equipment. Due to its superior insulation properties, SF{sub 6} is widely used in gas-insulated switchgear. However, the gas also has a very high global warming potential and the content of SF{sub 6} in the atmosphere is constantly increasing. The search for new insulation gases using classical breakdown experiments is discussed. A model for SF{sub 6} based on the stepped leader model is described. This calculates the breakdown voltages in arbitrary electrode configurations and under standard voltage waveforms. Thus, the thesis provides a method for the prediction of breakdown voltages of arbitrary field configurations under standard voltage waveforms for gases with electron-attaching properties. With this, further gases can be characterized for usage as high voltage insulation media.

  3. Prediction of breakdown voltages in novel gases for high voltage insulation

    International Nuclear Information System (INIS)

    Koch, M.

    2015-01-01

    This thesis submitted to the Swiss Federal Institute of Technology ETH in Zurich examines the use of sulphur hexafluoride (SF_6) and similar gases as important insulation media for high voltage equipment. Due to its superior insulation properties, SF_6 is widely used in gas-insulated switchgear. However, the gas also has a very high global warming potential and the content of SF_6 in the atmosphere is constantly increasing. The search for new insulation gases using classical breakdown experiments is discussed. A model for SF_6 based on the stepped leader model is described. This calculates the breakdown voltages in arbitrary electrode configurations and under standard voltage waveforms. Thus, the thesis provides a method for the prediction of breakdown voltages of arbitrary field configurations under standard voltage waveforms for gases with electron-attaching properties. With this, further gases can be characterized for usage as high voltage insulation media

  4. Concepts for evaluation of sound insulation of dwellings - from chaos to consensus?

    DEFF Research Database (Denmark)

    Rasmussen, Birgit; Rindel, Jens Holger

    2005-01-01

    Legal sound insulation requirements have existed more than 50 years in some countries, and single-number quantities for evaluation of sound insulation have existed nearly as long time. However, the concepts have changed considerably over time from simple arithmetic averaging of frequency bands......¬ments and classification schemes revealed significant differences of concepts. The paper summarizes the history of concepts, the disadvantages of the present chaos and the benefits of consensus concerning concepts for airborne and impact sound insulation between dwellings and airborne sound insulation of facades...... with a trend towards light-weight constructions are contradictory and challenging. This calls for exchange of data and experience, implying a need for harmonized concepts, including use of spectrum adaptation terms. The paper will provide input for future discussions in EAA TC-RBA WG4: "Sound insulation...

  5. Polyester Apparel Cutting Waste as Insulation Material

    OpenAIRE

    Trajković, Dušan; Jordeva, Sonja; Tomovska, Elena; Zafirova, Koleta

    2017-01-01

    Polyester waste is the dominant component of the clothing industry waste stream, yet its recycling in this industry is rarely addressed. This paper proposes using polyester cutting waste as an insulation blanket for roofing and buildings’ internal walls in order to reduce environmental pollution. The designed textile structures used waste cuttings from different polyester fabrics without opening the fabric to fibre. Thermal insulation, acoustic insulation, fire resistance and biodegradation o...

  6. Thermal Insulation System for Non-Vacuum Applications Including a Multilayer Composite

    Science.gov (United States)

    Fesmire, James E. (Inventor)

    2017-01-01

    The thermal insulation system of the present invention is for non-vacuum applications and is specifically tailored to the ambient pressure environment with any level of humidity or moisture. The thermal insulation system includes a multilayered composite including i) at least one thermal insulation layer and at least one compressible barrier layer provided as alternating, successive layers, and ii) at least one reflective film provided on at least one surface of the thermal insulation layer and/or said compressible barrier layer. The different layers and materials and their combinations are designed to provide low effective thermal conductivity for the system by managing all modes of heat transfer. The thermal insulation system includes an optional outer casing surrounding the multilayered composite. The thermal insulation system is particularly suited for use in any sub-ambient temperature environment where moisture or its adverse effects are a concern. The thermal insulation system provides physical resilience against damaging mechanical effects including compression, flexure, impact, vibration, and thermal expansion/contraction.

  7. Impact Verification of Aerogel Insulation Paint on Historic Brick Facades

    Science.gov (United States)

    Ganobjak, Michal; Kralova, Eva

    2017-10-01

    application, which, on the other hand may be unacceptable on the heritage conservation because of number of applications, time demand and financial costs. The effects of multiple layers on heritage attributes were not researched. Extrapolating the measured results, it can be expected that application of more than three layers of paint can significantly affect the aesthetic characteristics of the monument such as gloss and colours of historic brick facades. Due to specific material consistence of historic architecture and new insulation paint materials on the market, it is recommended to provide independent laboratory testing and on-site tests on facades of historic buildings in cooperation with the Monument Protection Board.

  8. Processing of insulators and semiconductors

    Science.gov (United States)

    Quick, Nathaniel R.; Joshi, Pooran C.; Duty, Chad Edward; Jellison, Jr., Gerald Earle; Angelini, Joseph Attilio

    2015-06-16

    A method is disclosed for processing an insulator material or a semiconductor material. The method includes pulsing a plasma lamp onto the material to diffuse a doping substance into the material, to activate the doping substance in the material or to metallize a large area region of the material. The method may further include pulsing a laser onto a selected region of the material to diffuse a doping substance into the material, to activate the doping substance in the material or to metallize a selected region of the material.

  9. Method of manufacturing a thermally insulating body

    Energy Technology Data Exchange (ETDEWEB)

    McWilliams, J.A.; Morgan, D.E.; Jackson, J.D.

    1988-10-11

    A method of manufacturing a microporous thermally insulating body comprises mixing together a finely divided microporous insulating material such as silica aerogel or pyrogenic silica and a solid ammonia-generating compound in particulate form, and compressing the mixture to form a thermally insulating body. The ammonia-generating compound is dispersed evenly throughout the insulating material and may comprise, for example, ammonium carbonate, ammonium acetate or urea. Preferably, the ammonia-generating compound comprises a mixture of about one third by weight of ammonium carbonate and about two thirds by weight of ammonium bicarbonate together with a small proportion of magnesium oxide. Experiments are described which illustrate the manufacturing process. 6 tabs.

  10. Dielectric and Insulating Technology 2004 : Review & Forecast

    Science.gov (United States)

    Okamoto, Tatsuki

    This article reports the state-of-art of DEIS activites. DEIS activiteis are basically based on the activites of 8-10 investigation committees’ under DEIS committee. Recent DEIS activites are categlized into three functions in this article and remarkable activity or trend of each category is mentioned. Those are activities on insulation diagnosis (AI application and asset management), activities on new insulation technology for power tansmission (high Tc super conducting cable insulation and all solid sinulated substation), and activities on new insulating materials (Nanocomposite).

  11. Low Permeability Polyimide Insulation, Phase I

    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...

  12. From insulation contracting to radon mitigation

    International Nuclear Information System (INIS)

    West, D.R.

    1990-01-01

    As the definition of house doctor has evolved over the past ten years and the field of energy services has grown more sophisticated, many contractors have expanded the services they offer their clients. This paper presents the story of one insulation contractor who has found a niche in radon testing and mitigation. The EPA now has a national program for the radon mitigator called the Radon Contractor Proficiency Program. The requirements include attending the Radon Technology for Mitigators course, passing an exam, and taking continuing education. In the Midwest, the most popular mitigation technique is the subslab depressurization system. To draw suction from under the slab, the system can take advantage of an existing sump crock or can penetrate the slab. Interior drain tiles collect water to empty into the crock, providing an excellent pathway to draw from. This mitigation process is explained

  13. Insulated electrocardiographic electrodes. [without paste electrolyte

    Science.gov (United States)

    David, R. M.; Portnoy, W. A. (Inventor)

    1975-01-01

    An integrated system is disclosed including an insulated electrode and an impedance transformer which can be assembled in a small plastic housing and used for the acquisition of electrocardiographic data. The electrode may be employed without a paste electrolyte and may be attached to the body for extended usage without producing skin reaction. The electrode comprises a thin layer of suitable nontoxic dielectric material preferably deposited by radio frequency sputtering onto a conductive substrate. The impedance transformer preferably comprises an operational amplifier having an FET input stage connected in the unity gain configuration which provides a very low lower cut-off frequency, a high input impedance with a very small input bias current, a low output impedance, and a high signal-to-noise ratio.

  14. Lateral topological crystalline insulator heterostructure

    Science.gov (United States)

    Sun, Qilong; Dai, Ying; Niu, Chengwang; Ma, Yandong; Wei, Wei; Yu, Lin; Huang, Baibiao

    2017-06-01

    The emergence of lateral heterostructures fabricated by two-dimensional building blocks brings many exciting realms in material science and device physics. Enriching available nanomaterials for creating such heterostructures and enabling the underlying new physics is highly coveted for the integration of next-generation devices. Here, we report a breakthrough in lateral heterostructure based on the monolayer square transition-metal dichalcogenides MX2 (M  =  W, X  =  S/Se) modules. Our results reveal that the MX2 lateral heterostructure (1S-MX2 LHS) can possess excellent thermal and dynamical stability. Remarkably, the highly desired two-dimensional topological crystalline insulator phase is confirmed by the calculated mirror Chern number {{n}\\text{M}}=-1 . A nontrivial band gap of 65 meV is obtained with SOC, indicating the potential for room-temperature observation and applications. The topologically protected edge states emerge at the edges of two different nanoribbons between the bulk band gap, which is consistent with the mirror Chern number. In addition, a strain-induced topological phase transition in 1S-MX2 LHS is also revealed, endowing the potential utilities in electronics and spintronics. Our predictions not only introduce new member and vitality into the studies of lateral heterostructures, but also highlight the promise of lateral heterostructure as appealing topological crystalline insulator platforms with excellent stability for future devices.

  15. 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.

  16. Topological Insulator Nanowires and Nanoribbons

    KAUST Repository

    Kong, Desheng

    2010-01-13

    Recent theoretical calculations and photoemission spectroscopy measurements on the bulk Bi2Se3 material show that it is a three-dimensional topological insulator possessing conductive surface states with nondegenerate spins, attractive for dissipationless electronics and spintronics applications. Nanoscale topological insulator materials have a large surface-to-volume ratio that can manifest the conductive surface states and are promising candidates for devices. Here we report the synthesis and characterization of high quality single crystalline Bi2Se5 nanomaterials with a variety of morphologies. The synthesis of Bi 2Se5 nanowires and nanoribbons employs Au-catalyzed vapor-liquid-solid (VLS) mechanism. Nanowires, which exhibit rough surfaces, are formed by stacking nanoplatelets along the axial direction of the wires. Nanoribbons are grown along [1120] direction with a rectangular cross-section and have diverse morphologies, including quasi-one-dimensional, sheetlike, zigzag and sawtooth shapes. Scanning tunneling microscopy (STM) studies on nanoribbons show atomically smooth surfaces with ∼ 1 nm step edges, indicating single Se-Bi-Se-Bi-Se quintuple layers. STM measurements reveal a honeycomb atomic lattice, suggesting that the STM tip couples not only to the top Se atomic layer, but also to the Bi atomic layer underneath, which opens up the possibility to investigate the contribution of different atomic orbitais to the topological surface states. Transport measurements of a single nanoribbon device (four terminal resistance and Hall resistance) show great promise for nanoribbons as candidates to study topological surface states. © 2010 American Chemical Society.

  17. Insulated transcriptional elements enable precise design of genetic circuits.

    Science.gov (United States)

    Zong, Yeqing; Zhang, Haoqian M; Lyu, Cheng; Ji, Xiangyu; Hou, Junran; Guo, Xian; Ouyang, Qi; Lou, Chunbo

    2017-07-03

    Rational engineering of biological systems is often complicated by the complex but unwanted interactions between cellular components at multiple levels. Here we address this issue at the level of prokaryotic transcription by insulating minimal promoters and operators to prevent their interaction and enable the biophysical modeling of synthetic transcription without free parameters. This approach allows genetic circuit design with extraordinary precision and diversity, and consequently simplifies the design-build-test-learn cycle of circuit engineering to a mix-and-match workflow. As a demonstration, combinatorial promoters encoding NOT-gate functions were designed from scratch with mean errors of 96% using our insulated transcription elements. Furthermore, four-node transcriptional networks with incoherent feed-forward loops that execute stripe-forming functions were obtained without any trial-and-error work. This insulation-based engineering strategy improves the resolution of genetic circuit technology and provides a simple approach for designing genetic circuits for systems and synthetic biology.Unwanted interactions between cellular components can complicate rational engineering of biological systems. Here the authors design insulated minimal promoters and operators that enable biophysical modeling of bacterial transcription without free parameters for precise circuit design.

  18. Reflective Insulation for Energy Conservation in South East Asia

    Science.gov (United States)

    San Teh, Khar; Yarbrough, David W.; Haw Lim, Chin; Salleh, Elias

    2017-05-01

    Thermal resistances have been measured for attic spaces insulated with reflective insulations. Three test units located in Malaysia were instrumented to provide heat flux and temperatures for the calculation of time-average RSI-values (RSI is representing R-value in SI units). The RSI for attics with enclosed reflective air spaces were in the range 2-3 m2·K/W while the uninsulated attics averaged about 0.4 m2·K/W. The RSI-values determined in this project were for heat-flow down, the predominant heat-flow direction for attic spaces in Equatorial regions. The observed thermal resistances due to the installation of the reflective insulation results in an 80-90% annual decrease in the heat transfer across the ceiling. This reduces utility usage for air conditioned units and improved comfort for occupants. The research demonstrates the use of transient data for the determination of thermal insulation performance and usefulness of enclosed reflective air spaces for thermal resistance.

  19. 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...

  20. 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.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2013-10-15

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

  2. Topological Insulators and Superconductors for Innovative Devices

    Science.gov (United States)

    2015-03-20

    Final 3. DATES COVERED (From - To) 20120321 - 20150320 4. TITLE AND SUBTITLE Topological insulators and superconductors for innovative...locking, which hold promise for various innovative devices. Similarly, topological superconductors are associated with exotic surface states, which...298 (Rev. 8/98) Prescribed by ANSI Std. Z39.18 Final Report Title: Topological Insulators and Superconductors for Innovative Devices

  3. Thermal insulation of high temperature reactors

    International Nuclear Information System (INIS)

    Cornille, Y.

    1975-01-01

    Operating conditions of HTR thermal insulation are given and heat insulators currently developed are described (fibers kept in position by metallic structures). For future applications and higher temperatures, research is directed towards solutions using ceramics or associating fibers and ceramics [fr

  4. Quantitative analysis of thermal insulation coatings

    DEFF Research Database (Denmark)

    Kiil, Søren

    2014-01-01

    This work concerns the development of simulation tools for mapping of insulation properties of thermal insulation coatings based on selected functional filler materials. A mathematical model, which includes the underlying physics (i.e. thermal conductivity of a heterogeneous two-component coating...

  5. Study of thermal conductivity of multilayer insulation

    Energy Technology Data Exchange (ETDEWEB)

    Dutta, D; Sundaram, S; Nath, G K; Sethuram, N P; Chandrasekharan, T; Varadarajan, T G [Heavy Water Division, Bhabha Atomic Research Centre, Mumbai (India)

    1994-06-01

    This paper presents experimental determination of the apparent thermal conductivity of multilayer insulation for a cryogenic system. The variation of thermal conductivity with residual gas pressure is studied and the optimum vacuum for good insulating performance is determined. Evaporation loss technique for heat-inleak determination is employed. (author). 3 refs., 3 figs.

  6. Insulation systems for superconducting transmission cables

    DEFF Research Database (Denmark)

    Tønnesen, Ole

    1996-01-01

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

  7. Study of thermal conductivity of multilayer insulation

    International Nuclear Information System (INIS)

    Dutta, D.; Sundaram, S.; Nath, G.K.; Sethuram, N.P.; Chandrasekharan, T.; Varadarajan, T.G.

    1994-01-01

    This paper presents experimental determination of the apparent thermal conductivity of multilayer insulation for a cryogenic system. The variation of thermal conductivity with residual gas pressure is studied and the optimum vacuum for good insulating performance is determined. Evaporation loss technique for heat-inleak determination is employed. (author)

  8. Aharonov–Bohm interference in topological insulator nanoribbons

    KAUST Repository

    Peng, Hailin; Lai, Keji; Kong, Desheng; Meister, Stefan; Chen, Yulin; Qi, Xiao-Liang; Zhang, Shou-Cheng; Shen, Zhi-Xun; Cui, Yi

    2009-01-01

    Topological insulators represent unusual phases of quantum matter with an insulating bulk gap and gapless edges or surface states. The two-dimensional topological insulator phase was predicted in HgTe quantum wells and confirmed by transport

  9. Modeling of Dynamic Responses in Building Insulation

    Directory of Open Access Journals (Sweden)

    Anna Antonyová

    2015-10-01

    Full Text Available In this research a measurement systemwas developedfor monitoring humidity and temperature in the cavity between the wall and the insulating material in the building envelope. This new technology does not disturb the insulating material during testing. The measurement system can also be applied to insulation fixed ten or twenty years earlier and sufficiently reveals the quality of the insulation. A mathematical model is proposed to characterize the dynamic responses in the cavity between the wall and the building insulation as influenced by weather conditions.These dynamic responses are manifested as a delay of both humidity and temperature changes in the cavity when compared with the changes in the ambient surrounding of the building. The process is then modeled through numerical methods and statistical analysis of the experimental data obtained using the new system of measurement.

  10. Topological Insulators Dirac Equation in Condensed Matters

    CERN Document Server

    Shen, Shun-Qing

    2012-01-01

    Topological insulators are insulating in the bulk, but process metallic states around its boundary owing to the topological origin of the band structure. The metallic edge or surface states are immune to weak disorder or impurities, and robust against the deformation of the system geometry. This book, Topological insulators, presents a unified description of topological insulators from one to three dimensions based on the modified Dirac equation. A series of solutions of the bound states near the boundary are derived, and the existing conditions of these solutions are described. Topological invariants and their applications to a variety of systems from one-dimensional polyacetalene, to two-dimensional quantum spin Hall effect and p-wave superconductors, and three-dimensional topological insulators and superconductors or superfluids are introduced, helping readers to better understand this fascinating new field. This book is intended for researchers and graduate students working in the field of topological in...

  11. Foam insulated transfer line test report

    International Nuclear Information System (INIS)

    Squier, D.M.

    1994-06-01

    Miles of underground insulated piping will be installed at the Hanford site to transfer liquid waste. Significant cost savings may be realized by using pre-fabricated polyurethane foam insulated piping. Measurements were made on sections of insulated pipe to determine the insulation's resistance to axial expansion of the pipe, the force required to compress the foam in the leg of an expansion loop and the time required for heat up and cool down of a buried piping loop. These measurements demonstrated that the peak axial force increases with the amount of adhesion between the encasement pipe and the insulation. The compressive strength of the foam is too great to accommodate the thermal growth of long straight pipe sections into the expansion loops. Mathematical models of the piping system's thermal behavior can be refined by data from the heated piping loop

  12. Coupling of an applied field magnetically insulated ion diode to a high power magnetically insulated transmission line system

    International Nuclear Information System (INIS)

    Maenchen, J.E.

    1983-01-01

    The coupling of energy from a high power pulsed accelerator through a long triplate magnetically insulated transmission line (MITL) in vacuum to an annular applied magnetic field insulated extraction ion diode is examined. The narrow power transport window and the wave front erosion of the MITL set stringent impedance history conditions on the diode load. A new ion diode design developed to satisfy these criteria with marginal electron insulation is presented. The LION accelerator is used to provide a positive polarity 1.5 MV, 350 kA, 40 ns FWHM pulse with a 30 kA/ns current rate from a triplate MITL source. A transition converts the triplate into a cylindrical cross section which flares into the ion diode load. Extensive current and voltage measurements performed along this structure and on the extracted ion beam provide conclusive evidence that the self insulation condition of the MITL is maintained in the transition by current loss alone. The ion diode utilizes a radial magnetic field between a grounded cathode annular emission tip and a disk anode. A 50 cm 2 dielectric/metal anode area serves as the ion plasma source subject to direct electron bombardment from the opposing cathode tip under marginal magnetic insulation conditions. The ions extracted cross the radial magnetic field and exit the diode volume as an annular cross section beam of peak current about 100 kA. The diode current gradually converts from the initial electron flow to nearly 100% ion current after 30 ns, coupling 60% of the diode energy into ions

  13. Luminescence from metals and insulators

    International Nuclear Information System (INIS)

    Crawford, O.H.

    1985-01-01

    The term luminescence is normally applied to light emission that is not explainable by the mechanisms discussed by the other speakers in this meeting. Specifically, it is not transition radiation, surface plasmon radiation, or bremsstrahlung. One normally thinks of luminescence as arising from one-electron transitions within a medium. This talk consists of an overview of luminescence from condensed matter under irradiation by either energetic particles or photons. The author begins with organic molecules, where luminescence is best understood, and then discusses inorganic insulators and metals. Finally, the dependence of yield upon projectile species and velocity is discussed, and predictions are made concerning the relative effectiveness of electrons, protons, and hydrogen atoms in exciting luminescence

  14. Handbook of Thermal Insulation Applications.

    Science.gov (United States)

    1983-01-01

    Wiuppuoror *tIe beamsWiefag ln~ td ~oair ilmstool beams Plate 18. Metal Building Ceilings - A 18b: Fir* hataird rathge may limit the use of foam Insulation...RFCTANGUI.AR SOL TD A = 2(WxL+LxH+HxW) B V = WxLxH H L TRAPEZOID A 2 (A + B) x H A CONE A -n xRxS+ i xR 2 B V =( /3)x R2 x H TRIANGLE A BxH A- 2 CYLI NDER H 2...FABRICATIIG RECTANGULAR HEATING AND COOLING DUCTWORK. FIBERGLAS DUCT BOARD OWENS-CORNING FIBERGLAS CORP GLASS FIBER RIGID BOARD WITH ALUMINUM 4bD FOIL VAPOR

  15. Design of indoor furniture with acoustic insulation and noise reduction function

    Science.gov (United States)

    Chen, Ziqiang; Lyu, Jianhua; Chen, Ming

    2018-05-01

    In this article, the current status of noise pollution research is analyzed and indoor noise pollution hazard on human body is discussed taking noise pollution as entry point to better understand people's needs in this concern, and it comes to the conclusion that indoor furniture with noise insulation function is required; In addition, the design status and necessity of indoor furniture with noise insulation function are expounded and the material property, structure design essentials and form design are analyzed according to sound transmission principles. In the end, design case study is presented to provide an effective way for design of indoor furniture with acoustic insulation function that meets people's needs.

  16. Quantum spin/valley Hall effect and topological insulator phase transitions in silicene

    KAUST Repository

    Tahir, M.

    2013-04-26

    We present a theoretical realization of quantum spin and quantum valley Hall effects in silicene. We show that combination of an electric field and intrinsic spin-orbit interaction leads to quantum phase transitions at the charge neutrality point. This phase transition from a two dimensional topological insulator to a trivial insulating state is accompanied by a quenching of the quantum spin Hall effect and the onset of a quantum valley Hall effect, providing a tool to experimentally tune the topological state of silicene. In contrast to graphene and other conventional topological insulators, the proposed effects in silicene are accessible to experiments.

  17. Measure Guideline: Incorporating Thick Layers of Exterior Rigid Insulation on Walls

    Energy Technology Data Exchange (ETDEWEB)

    Lstiburek, Joseph [Building Science Corporation, Westford, MA (United States); Baker, Peter [Building Science Corporation, Westford, MA (United States)

    2015-04-01

    This measure guideline provides information about the design and construction of wall assemblies that use layers of rigid exterior insulation thicker than 1-½ inches and that require a secondary cladding attachment location exterior to the insulation. The guideline is separated into several distinct sections that cover: fundamental building science principles relating to the use of exterior insulation on wall assemblies; design principles for tailoring this use to the specific project goals and requirements; and construction detailing to increase understanding about implementing the various design elements.

  18. Measure Guideline. Incorporating Thick Layers of Exterior Rigid Insulation on Walls

    Energy Technology Data Exchange (ETDEWEB)

    Lstiburek, Joseph [Building Science Corporation, Westford, MA (United States); Baker, Peter [Building Science Corporation, Westford, MA (United States)

    2015-04-09

    This measure guideline, written by the U.S. Department of Energy’s Building America team Building Science Corporation, provides information about the design and construction of wall assemblies that use layers of rigid exterior insulation thicker than 1-½ in. and that require a secondary cladding attachment location exterior to the insulation. The guideline is separated into several distinct sections that cover: (1) fundamental building science principles relating to the use of exterior insulation on wall assemblies; (2) design principles for tailoring this use to the specific project goals and requirements; and (3) construction detailing to increase understanding about implementing the various design elements.

  19. Quantum spin/valley Hall effect and topological insulator phase transitions in silicene

    KAUST Repository

    Tahir, M.; Manchon, Aurelien; Sabeeh, K.; Schwingenschlö gl, Udo

    2013-01-01

    We present a theoretical realization of quantum spin and quantum valley Hall effects in silicene. We show that combination of an electric field and intrinsic spin-orbit interaction leads to quantum phase transitions at the charge neutrality point. This phase transition from a two dimensional topological insulator to a trivial insulating state is accompanied by a quenching of the quantum spin Hall effect and the onset of a quantum valley Hall effect, providing a tool to experimentally tune the topological state of silicene. In contrast to graphene and other conventional topological insulators, the proposed effects in silicene are accessible to experiments.

  20. Medicare Provider Data - Hospice Providers

    Data.gov (United States)

    U.S. Department of Health & Human Services — The Hospice Utilization and Payment Public Use File provides information on services provided to Medicare beneficiaries by hospice providers. The Hospice PUF...

  1. Layered Thermal Insulation Systems for Industrial and Commercial Applications

    Science.gov (United States)

    Fesmire, James E.

    2015-01-01

    From the high performance arena of cryogenic equipment, several different layered thermal insulation systems have been developed for industrial and commercial applications. In addition to the proven areas in cold-work applications for piping and tanks, the new Layered Composite Insulation for Extreme Environments (LCX) has potential for broader industrial use as well as for commercial applications. The LCX technology provides a unique combination of thermal, mechanical, and weathering performance capability that is both cost-effective and enabling. Industry applications may include, for example, liquid nitrogen (LN2) systems for food processing, liquefied natural gas (LNG) systems for transportation or power, and chilled water cooling facilities. Example commercial applications may include commercial residential building construction, hot water piping, HVAC systems, refrigerated trucks, cold chain shipping containers, and a various consumer products. The LCX system is highly tailorable to the end-use application and can be pre-fabricated or field assembled as needed. Product forms of LCX include rigid sheets, semi-flexible sheets, cylindrical clam-shells, removable covers, or flexible strips for wrapping. With increasing system control and reliability requirements as well as demands for higher energy efficiencies, thermal insulation in harsh environments is a growing challenge. The LCX technology grew out of solving problems in the insulation of mechanically complex cryogenic systems that must operate in outdoor, humid conditions. Insulation for cold work includes equipment for everything from liquid helium to chilled water. And in the middle are systems for LNG, LN2, liquid oxygen (LO2), liquid hydrogen (LH2) that must operate in the ambient environment. Different LCX systems have been demonstrated for sub-ambient conditions but are capable of moderately high temperature applications as well.

  2. Thermographic Methods of Detecting Insulation Voids in Large Cryogenic Tanks

    Science.gov (United States)

    Arens, Ellen; Nurge, Mark; Youngquist, Robert; Starr, Stanley

    2010-01-01

    Four very large (900Kgal) cryogenic liquid hydrogen and oxygen storage tanks at Kennedy Space Center's LC-39 launch pads were constructed in 1965 to support the Apollo/Saturn V Program and continue to support the Space Shuttle Program. These double-walled spherical tanks with powdered insulation in the annular region, have received minimal refurbishment or even inspection over the years. Intrusively inspecting these tanks would mean a significant down time to the program as the cryogenic liquid and the perlite insulation would have to be removed which would be a significant task and long-term schedule disruption. A study of the tanks was performed to determine the extent to which performance and structural information could be revealed without intrusive inspection. Thermal images of the tanks were taken over a variety of environmental conditions to determine the best conditions under which to compare and use thermography as a health monitoring technique as the tanks continue to age. The settling and subsequent compaction of insulation is a serious concern for cryogenic tanks. Comparison of images from the tanks reveals significant variations in the insulation in the annual regions and point to the use of thermography as a way to monitor for insulation migration and possible compaction. These measurements, when combined with mathematical models of historical boil-off data provide key insight to the condition of the vessels. Acceptance testing methods for new tanks, before they are filled with cryogenic commodity (and thereby thermally cycled), are needed and we explore how thermography can be used to accomplish this.

  3. Structural and proximity-induced ferromagnetic properties of topological insulator-magnetic insulator heterostructures

    Directory of Open Access Journals (Sweden)

    Zilong Jiang

    2016-05-01

    Full Text Available The spontaneously broken time reversal symmetry can lead to the formation of an energy gap in the Dirac spectrum of the surface states of a topological insulator (TI which can consequently give rise to a variety of interesting phenomena potentially useful for spintronics. In this work, we couple a non-magnetic TI to a high Curie temperature TC magnetic insulator to induce strong exchange interaction via the proximity effect. We have successfully grown 5 quintuple layer thick ternary TI (BixSb1-x2Te3 films on atomically flat yttrium iron garnet (YIG film with the combination of molecular beam epitaxy and pulsed laser deposition, in which the Fermi level position relative to the Dirac point is varied by controlling the Bi:Sb ratio. The anomalous Hall effect (AHE and suppressed weak antilocalization (WAL measured under out of plane magnetic fields reveal that the TI surface in contact with YIG is magnetized. Our high-quality (BixSb1-x2Te3/Y IG heterostructure provides a tunable system for exploring the quantum anomalous Hall effect (QAHE at higher temperatures in TI-based spintronic devices.

  4. Electrical insulator requirements for mirror fusion reactors

    International Nuclear Information System (INIS)

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

    1977-01-01

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

  5. Excavationless Exterior Foundation Insulation Field Study

    Energy Technology Data Exchange (ETDEWEB)

    Schirber, T.; Mosiman, G.; Ojczyk, C.

    2014-10-01

    Building science research supports installing exterior (soil side) foundation insulation as the optimal method to enhance the hygrothermal performance of new homes. With exterior foundation insulation, water management strategies are maximized while insulating the basement space and ensuring a more even temperature at the foundation wall. However, such an approach can be very costly and disruptive when applied to an existing home, requiring deep excavation around the entire house. The NorthernSTAR Building America Partnership team implemented an innovative, minimally invasive foundation insulation upgrade technique on an existing home. The approach consisted of using hydrovac excavation technology combined with a liquid insulating foam. The team was able to excavate a continuous 4" wide by 4' to 5' deep trench around the entire house, 128 linear feet, except for one small part under the stoop that was obstructed with concrete debris. The combination pressure washer and vacuum extraction technology also enabled the elimination of large trenches and soil stockpiles normally produced by backhoe excavation. The resulting trench was filled with liquid insulating foam, which also served as a water-control layer of the assembly. The insulation was brought above grade using a liquid foam/rigid foam hybrid system and terminated at the top of the rim joist. Cost savings over the traditional excavation process ranged from 23% to 50%. The excavationless process could result in even greater savings since replacement of building structures, exterior features, utility meters, and landscaping would be minimal or non-existent in an excavationless process.

  6. Excavationless Exterior Foundation Insulation Field Study

    Energy Technology Data Exchange (ETDEWEB)

    Schirber, T. [NorthernSTAR, Minneaplolis, MN (United States); Mosiman, G. [NorthernSTAR, Minneaplolis, MN (United States); Ojczyk, C. [NorthernSTAR, Minneaplolis, MN (United States)

    2014-09-01

    Building science research supports installing exterior (soil side) foundation insulation as the optimal method to enhance the hygrothermal performance of new homes. With exterior foundation insulation, water management strategies are maximized while insulating the basement space and ensuring a more even temperature at the foundation wall. However, such an approach can be very costly and disruptive when applied to an existing home, requiring deep excavation around the entire house. The NorthernSTAR Building America Partnership team implemented an innovative, minimally invasive foundation insulation upgrade technique on an existing home. The approach consisted of using hydrovac excavation technology combined with liquid insulating foam. The team was able to excavate a continuous 4 inches wide by 4 feet to 5 feet deep trench around the entire house, 128 linear feet, except for one small part under the stoop that was obstructed with concrete debris. The combination pressure washer and vacuum extraction technology also enabled the elimination of large trenches and soil stockpiles normally produced by backhoe excavation. The resulting trench was filled with liquid insulating foam, which also served as a water-control layer of the assembly. The insulation was brought above grade using a liquid foam/rigid foam hybrid system and terminated at the top of the rim joist. Cost savings over the traditional excavation process ranged from 23% to 50%. The excavationless process could result in even greater savings since replacement of building structures, exterior features, utility meters, and landscaping would be minimal or non-existent in an excavationless process.

  7. Mott metal-insulator transition in the doped Hubbard-Holstein model

    Science.gov (United States)

    Kurdestany, Jamshid Moradi; Satpathy, S.

    2017-08-01

    Motivated by the current interest in the understanding of the Mott insulators away from half-filling, observed in many perovskite oxides, we study the Mott metal-insulator transition in the doped Hubbard-Holstein model using the Hartree-Fock mean field theory. The Hubbard-Holstein model is the simplest model containing both the Coulomb and the electron-lattice interactions, which are important ingredients in the physics of the perovskite oxides. In contrast to the half-filled Hubbard model, which always results in a single phase (either metallic or insulating), our results show that away from half-filling, a mixed phase of metallic and insulating regions occurs. As the dopant concentration is increased, the metallic part progressively grows in volume, until it exceeds the percolation threshold, leading to percolative conduction. This happens above a critical dopant concentration δc, which, depending on the strength of the electron-lattice interaction, can be a significant fraction of unity. This means that the material could be insulating even for a substantial amount of doping, in contrast to the expectation that doped holes would destroy the insulating behavior of the half-filled Hubbard model. While effects of fluctuation beyond the mean field remain an open question, our results provide a starting point for the understanding of the density-driven metal-insulator transition observed in many complex oxides.

  8. 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.

  9. 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.

  10. Structure, Mechanism, and Application of Vacuum Insulation Panels in Chinese Buildings

    Directory of Open Access Journals (Sweden)

    Changhai Peng

    2016-01-01

    Full Text Available Thermal insulation is one of the most used approaches to reduce energy consumption in buildings. Vacuum insulation panels (VIPs are new thermal insulation materials that have been used in the domestic and overseas market in the last 20 years. Due to the vacuum thermal insulation technology of these new materials, their thermal conductivity can be as low as 0.004 W/(m·K at the center of panels. In addition, VIPs that are composites with inorganic core and an envelope out of commonly three metallized PET layers and a PE sealing layer can provide B class fire resistance (their core materials are not flammable and are classified as A1. Compared with other conventional thermal insulation materials, the thermal insulation and fire resistance performances form the foundation of VIP’s applications in the construction industry. The structure and thermal insulation mechanism of VIP and their application potential and problems in Chinese buildings are described in detail.

  11. An insulating grid spacer for large-area MICROMEGAS chambers

    International Nuclear Information System (INIS)

    Bernard, D.; Delagrange, H.; D'Enterria, D.G.; Guay, M.L.M. Le; Martinez, G.; Mora, M.J.; Pichot, P.; Roy, D.; Schutz, Y.; Gandi, A.; Oliveira, R. de

    2002-01-01

    We present a novel design for large-area gaseous detectors based on the MICROMEGAS technology. This technology incorporates an insulating grid, sandwiched between the micro-mesh and the anode-pad plane, which provides a uniform 200 μm amplification gap. The uniformity of the amplification gap thickness has been verified. The gain performances of the detector are presented and compared to the values obtained with detectors using cylindrical micro spacers. The new design presents several technical and financial advantages

  12. Development of a New Insulation Approach for the LHC Main 13 kA Interconnection Splices

    CERN Document Server

    Lackner, F; Fessia, P; Lopez, R; Prin, H; Tock, J Ph

    2012-01-01

    In the long LHC (Large Hadron Collider) shutdown in 2013 it is foreseen to intervene on all the 13 kA interconnections in order to guarantee the necessary margin and redundancy to provide safe LHC operation at 7 TeV per beam. This implies reinforcement of the present interconnection configuration including a new insulation scheme of the busbars. The purpose of the new insulation model is to provide dielectric insulation with at least the same performance as its predecessor currently installed in the LHC machine, but in addition to contain the Lorentz forces. This paper describes the analytic and empirical approach of development to reach a new insulation concept based on state of the art materials and manufacturing techniques.

  13. Estimation of thermal insulation performance in multi-layer insulator for liquid helium pipe

    International Nuclear Information System (INIS)

    Shibanuma, Kiyoshi; Kuriyama, Masaaki; Shibata, Takemasa

    1991-01-01

    For a multi-layer insulator around the liquid helium pipes for cryopumps of JT-60 NBI, a multi-layer insulator composed of 10 layers, which can be wound around the pipe at the same time and in which the respective layers are in concentric circles by shifting them in arrangement, has been developed and tested. As the result, it was shown that the newly developed multi-layer insulator has better thermal insulation performance than the existing one, i.e. the heat load of the newly developed insulator composed of 10 layers was reduced to 1/3 the heat load of the existing insulator, and the heat leak at the joint of the insulator in longitudinal direction of the pipe was negligible. In order to clarify thermal characteristics of the multi-layer insulator, the heat transfer through the insulator has been analyzed considering the radiation heat transfer by the netting spacer between the reflectors, and the temperature dependence on the emissivities and the heat transmission coefficients of these two components of the insulator. The analytical results were in good agreements with the experimental ones, so that the analytical method was shown to be valid. Concerning the influence of the number of layers and the layer density on the insulation performance of the insulator, analytical results showed that the multi-layer insulator with the number of layer about N = 20 and the layer density below 2.0 layer/mm was the most effective for the liquid helium pipe of a JT-60 cryopump. (author)

  14. Measure Guideline. Wall Air Sealing and Insulation Methods in Existing Homes; An Overview of Opportunity and Process

    Energy Technology Data Exchange (ETDEWEB)

    Roberts, S. [NAHB Research Center Industry Partnership, Upper Marlboro, MD (United States); Stephenson, R. [NAHB Research Center Industry Partnership, Upper Marlboro, MD (United States)

    2012-09-01

    This guide provides renovators and retrofit contractors an overview of considerations when including wall air sealing and insulation in an energy retrofit project. It also outlines the potential project risks, various materials for insulating, possible field inspections needed, installation procedures, as well as the benefits and drawbacks.

  15. Effects of Exterior Insulation on Moisture Performance of Wood-Frame Walls in the Pacific Northwest: Measurements and Hygrothermal Modeling

    Science.gov (United States)

    Samuel V. Glass; Borjen Yeh; Benjamin J. Herzog

    2016-01-01

    Continuous exterior insulation on above-grade walls is becoming more common in many parts of North America. It is generally accepted that exterior insulation provides advantages for energy performance, by reducing thermal bridging, and for moisture performance, by warming the wood structural members, thereby reducing the potential for wintertime moisture accumulation....

  16. Vacuum insulation - Panel properties and building applications. HiPTI - High Performance Thermal Insulation - IEA/ECBCS Annex 39 - Final report

    Energy Technology Data Exchange (ETDEWEB)

    Erb, M. (ed.)

    2005-12-15

    This paper takes a look at the properties of vacuum insulation panels (VIP) that have already been developed some time ago for use in appliances such as refrigerators and deep-freezers. Their insulation performance is a factor of five to ten times better than that of conventional insulation. The paper discusses the use of such panels in buildings to provide thin, highly-insulating constructions for walls, roofs and floors. The motivation for examining the applicability of high performance thermal insulation in buildings is discussed, including solutions where severe space limitations and other technical and aesthetic considerations exist. The use of nano-structured materials and laminated foils is examined and discussed. The questions arising from the use of such panels in buildings is discussed and the open questions and risks involved are examined. Finally, an outlook on the introduction of VIP technology is presented and quality assurance aspects are examined. This work was done within the framework of the Task 39 'High Performance Thermal Insulation' of the 'Energy Conservation in Buildings and Community Systems ECBCS' programme of the International Energy Agency IEA.

  17. Raman Spectral Characteristics of Oil-Paper Insulation and Its Application to Ageing Stage Assessment of Oil-Immersed Transformers

    Directory of Open Access Journals (Sweden)

    Jingxin Zou

    2016-11-01

    Full Text Available The aging of oil-paper insulation in power transformers may cause serious power failures. Thus, effective monitoring of the condition of the transformer insulation is the key to prevent major accidents. The purpose of this study was to explore the feasibility of confocal laser Raman spectroscopy (CLRS for assessing the aging condition of oil-paper insulation. Oil-paper insulation samples were subjected to thermal accelerated ageing at 120 °C for up to 160 days according to the procedure described in the IEEE Guide. Meanwhile, the dimension of the Raman spectrum of the insulation oil was reduced by principal component analysis (PCA. The 160 oil-paper insulation samples were divided into five aging stages as training samples by clustering analysis and with the use of the degree of polymerization of the insulating papers. In addition, the features of the Raman spectrum were used as the inputs of a multi-classification support vector machine. Finally, 105 oil-paper insulation testing samples aged at a temperature of 130 °C were used to further test the diagnostic capability and universality of the established algorithm. Results demonstrated that CLRS in conjunction with the PCA-SVM technique provides a new way for aging stage assessment of oil-paper insulation equipment in the field.

  18. External insulation with cellular plastic materials

    DEFF Research Database (Denmark)

    Sørensen, Lars Schiøtt; Nielsen, Anker

    2014-01-01

    External thermal insulation composite systems (ETICS) can be used as extra insulation of existing buildings. The system can be made of cellular plastic materials or mineral wool. There is a European Technical guideline, ETAG 004, that describe the tests that shall be conducted on such systems....... This paper gives a comparison of systems with mineral wool and cellular plastic, based on experience from practice and literature. It is important to look at the details in the system and at long time stability of the properties such as thermal insulation, moisture and fire. Investigation of fire properties...

  19. Fabrication of heterojunction solar cells by improved tin oxide deposition on insulating layer

    Science.gov (United States)

    Feng, Tom; Ghosh, Amal K.

    1980-01-01

    Highly efficient tin oxide-silicon heterojunction solar cells are prepared by heating a silicon substrate, having an insulating layer thereon, to provide a substrate temperature in the range of about 300.degree. C. to about 400.degree. C. and thereafter spraying the so-heated substrate with a solution of tin tetrachloride in a organic ester boiling below about 250.degree. C. Preferably the insulating layer is naturally grown silicon oxide layer.

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

    International Nuclear Information System (INIS)

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

    1986-01-01

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

  1. Surface electrical resistivity of insulators

    International Nuclear Information System (INIS)

    Senn, B. C.; Liesegang, J.

    1996-01-01

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

  2. Irradiation effects on organic insulators

    International Nuclear Information System (INIS)

    Kasen, M.B.

    1986-01-01

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

  3. Topological insulators Dirac equation in condensed matter

    CERN Document Server

    Shen, Shun-Qing

    2017-01-01

    This new edition presents a unified description of these insulators from one to three dimensions based on the modified Dirac equation. It derives a series of solutions of the bound states near the boundary, and describes the current status of these solutions. Readers are introduced to topological invariants and their applications to a variety of systems from one-dimensional polyacetylene, to two-dimensional quantum spin Hall effect and p-wave superconductors, three-dimensional topological insulators and superconductors or superfluids, and topological Weyl semimetals, helping them to better understand this fascinating field. To reflect research advances in topological insulators, several parts of the book have been updated for the second edition, including: Spin-Triplet Superconductors, Superconductivity in Doped Topological Insulators, Detection of Majorana Fermions and so on. In particular, the book features a new chapter on Weyl semimetals, a topic that has attracted considerable attention and has already b...

  4. Cryogenic Insulation Standard Data and Methodologies

    Data.gov (United States)

    National Aeronautics and Space Administration — Extending some recent developments in the area of technical consensus standards for cryogenic thermal insulation systems, a preliminary Inter-Laboratory Study of...

  5. Electrical breakdown studies with Mycalex insulators

    International Nuclear Information System (INIS)

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

    2003-01-01

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

  6. Characterization techniques for ion bombarded insulators

    International Nuclear Information System (INIS)

    Borders, J.A.

    1987-01-01

    The chapter gives a comprehensive review of the experimental methods for the analysis of ion-bombarded insulators including optical and structural methods, resonance, energetic ion methods, and surface techniques. 48 refs.; 34 figs

  7. (ajst) effects of ground insulation and greenhouse

    African Journals Online (AJOL)

    NORBERT OPIYO AKECH

    and quality of biogas generation from dairy cattle dung. The effects ... Therefore ground insulation of plastic biogas digester under greenhouse conditions significantly enhances ..... The low values obtained did not suggest failure of the system ...

  8. Improved thermal monitoring of rotating machine insulation

    International Nuclear Information System (INIS)

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

    1991-01-01

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

  9. Thermal insulation performance of green roof systems

    Energy Technology Data Exchange (ETDEWEB)

    Celik, Serdar; Morgan, Susan; Retzlaff, William; Once, Orcun [southern Illinois University (United States)], e-mail: scelik@siue.edu, e-mail: smorgan@siue.edu, e-mail: wretzla@siue.edu, e-mail: oonce@siue.edu

    2011-07-01

    With the increasing costs of energy, good building insulation has become increasingly important. Among existing insulation techniques is the green roof system, which consists of covering the roof of a building envelop with plants. The aim of this paper is to assess the impact of vegetation type and growth media on the thermal performance of green roof systems. Twelve different green roof samples were made with 4 different growth media and 3 sedum types. Temperature at the sample base was recorded every 15 minutes for 3 years; the insulation behavior was then analysed. Results showed that the insulation characteristics were achieved with a combination of haydite and sedum sexangulare. This study demonstrated that the choice of growth media and vegetation is important to the green roof system's performance; further research is required to better understand the interactions between growth media and plant roots.

  10. Aluminum nitride insulating films for MOSFET devices

    Science.gov (United States)

    Lewicki, G. W.; Maserjian, J.

    1972-01-01

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

  11. Effect of Sweating on Insulation of Footwear.

    Science.gov (United States)

    Kuklane, Kalev; Holmér, Ingvar

    1998-01-01

    The study aimed to find out the influence of sweating on footwear insulation with a thermal foot model. Simultaneously, the influence of applied weight (35 kg), sock, and steel toe cap were studied. Water to 3 sweat glands was supplied with a pump at the rate of 10 g/hr in total. Four models of boots with steel toe caps were tested. The same models were manufactured also without steel toe. Sweating reduced footwear insulation 19-25% (30-37% in toes). During static conditions, only a minimal amount of sweat evaporated from boots. Weight affected sole insulation: Reduction depended on compressibility of sole material. The influence of steel toe varied with insulation. The method of thermal foot model appears to be a practical tool for footwear evaluation.

  12. Grandstand view of phenolic foam insulation

    Energy Technology Data Exchange (ETDEWEB)

    1987-03-01

    Stadium Insulation Ltd, manufacture pipe sections, tank and vessel insulation products in Lowphen, polyisocyanurate, polyurethane foams and expanded polystyrene, though for certain specialist applications, cork is still employed in small quantities. Currently the emphasis is very much on Lowphen, the company's range of pipe sections based on phenolic foam. The company's manufacturing and marketing effort reflects the increasing market trend towards the use of insulating material capable of withstanding higher temperatures, and phenolic foam neatly satisfies the demand since it is capable of use at temperatures up to 140/sup 0/C. Moreover, phenolic foam has the lowest K value at 0.02W/m/sup 0/C of any of the currently available range of insulating materials, and while the product is slightly more expensive than alternatives such as polyisocyanurate and polyurethane, its high performance offsets that premium.

  13. Thermal performance measurement and application of a multilayer insulator for emergency architecture

    International Nuclear Information System (INIS)

    Salvalai, Graziano; Imperadori, Marco; Scaccabarozzi, Diego; Pusceddu, Cristina

    2015-01-01

    Lightness coupled with a quick assembly method is crucial for emergency architecture in post-disaster area where accessibility and action time play a huge barer to rescue people. In this prospective, the following work analyses the potentiality (technological and thermal performances) of multilayer insulator for a new shelter envelope able to provide superior thermal comfort for the users. The thermal characteristics are derived experimentally by means of a guard ring apparatus under different working temperatures. Tests are performed on the multilayer insulator itself and on a composite structure, made of the multilayer insulator and two air gaps wrapped by a polyester cover, which is the core of a new lightweight emergency architecture. Experimental results show good agreement with literature data, providing a thermal conductivity and transmittance of about 0.04 W/(m °C) and 1.6 W/(m 2  °C) for the tested multilayer. The composite structure called Thermo Reflective Multilayer System (TRMS) shows better insulation performances, providing a thermal transmittance set to 0.85 W/(m 2  °C). A thermal model of an emergency tent based on the new insulating structure (TRMS) has been developed and its thermal performances have been compared with those of a UNHCR traditional emergency shelter. The shelter model was simulated (Trnsys v.17 environment) in the winter season considering the climate of Belgrade and using only the casual gains from occupant and solar radiation through opaque wall. Numerical simulations evidenced that the new insulating composite envelope reduces required heating load of about two and four times with respect to the traditional insulation. The study sets a starting point to develop a lightweight emergency architecture made with a combination between multilayer, air, polyester and vulcanized rubber. - Highlights: • Multilayer insulator tested by means of a guard ring apparatus. • Thermo reflective multilayer system (TRMS) development

  14. Single atom anisotropic magnetoresistance on a topological insulator surface

    KAUST Repository

    Narayan, Awadhesh

    2015-03-12

    © 2015 IOP Publishing Ltd and Deutsche Physikalische Gesellschaft. We demonstrate single atom anisotropic magnetoresistance on the surface of a topological insulator, arising from the interplay between the helical spin-momentum-locked surface electronic structure and the hybridization of the magnetic adatom states. Our first-principles quantum transport calculations based on density functional theory for Mn on Bi2Se3 elucidate the underlying mechanism. We complement our findings with a two dimensional model valid for both single adatoms and magnetic clusters, which leads to a proposed device setup for experimental realization. Our results provide an explanation for the conflicting scattering experiments on magnetic adatoms on topological insulator surfaces, and reveal the real space spin texture around the magnetic impurity.

  15. Single-spin addressing in an atomic Mott insulator

    DEFF Research Database (Denmark)

    Weitenberg, Christof; Endres, Manuel; Sherson, Jacob

    2011-01-01

    directly monitored the tunnelling quantum dynamics of single atoms in the lattice prepared along a single line, and observed that our addressing scheme leaves the atoms in the motional ground state. The results should enable studies of entropy transport and the quantum dynamics of spin impurities...... and quantum spin dynamics. Here we demonstrate how such control can be implemented at the most fundamental level of a single spin at a specific site of an optical lattice. Using a tightly focused laser beam together with a microwave field, we were able to flip the spin of individual atoms in a Mott insulator...... with sub-diffraction-limited resolution, well below the lattice spacing. The Mott insulator provided us with a large two-dimensional array of perfectly arranged atoms, in which we created arbitrary spin patterns by sequentially addressing selected lattice sites after freezing out the atom distribution. We...

  16. Effect of insulating concrete forms in concrete compresive strength

    Science.gov (United States)

    Martinez Jerez, Silvio R.

    The subject presented in this thesis is the effect of Insulating Concrete Forms (ICF's) on concrete compressive strength. This work seeks to identify if concrete cured in ICF's has an effect in compressive strength due to the thermal insulation provided by the forms. Modern construction is moving to energy efficient buildings and ICF's is becoming more popular in new developments. The thesis used a concrete mixture and a mortar mixture to investigate the effects of ICF's on concrete compressive strength. After the experimentations were performed, it was concluded that the ICF's do affect concrete strength. It was found that the forms increase concrete strength without the need for additional curing water. An increase of 50% in strength at 56 days was obtained. It was concluded that the longer concrete cures inside ICF's, the higher strength it reaches, and that ICF's effect on concrete strength is proportional to volume of concrete.

  17. Insulator Contamination Forecasting Based on Fractal Analysis of Leakage Current

    Directory of Open Access Journals (Sweden)

    Bing Luo

    2012-07-01

    Full Text Available In this paper, an artificial pollution test is carried out to study the leakage current of porcelain insulators. Fractal theory is adopted to extract the characteristics hidden in leakage current waveforms. Fractal dimensions of the leakage current for the security, forecast and danger zones are analyzed under four types of degrees of contamination. The mean value and the standard deviation of the fractal dimension in the forecast zone are calculated to characterize the differences. The analysis reveals large differences in the fractal dimension of leakage current under different contamination discharge stages and degrees. The experimental and calculation results suggest that the fractal dimension of a leakage current waveform can be used as a new indicator of the discharge process and contamination degree of insulators. The results provide new methods and valid indicators for forecasting contamination flashovers.

  18. Total dose hardening of buried insulator in implanted silicon-on-insulator structures

    International Nuclear Information System (INIS)

    Mao, B.Y.; Chen, C.E.; Pollack, G.; Hughes, H.L.; Davis, G.E.

    1987-01-01

    Total dose characteristics of the buried insulator in implanted silicon-on-insulator (SOI) substrates have been studied using MOS transistors. The threshold voltage shift of the parasitic back channel transistor, which is controlled by charge trapping in the buried insulator, is reduced by lowering the oxygen dose as well as by an additional nitrogen implant, without degrading the front channel transistor characteristics. The improvements in the radiation characteristics of the buried insulator are attributed to the decrease in the buried oxide thickness or to the presence of the interfacial oxynitride layer formed by the oxygen and nitrogen implants

  19. Preliminary data evaluation for thermal insulation characterization testing

    International Nuclear Information System (INIS)

    DeClue, J.F.; Moses, S.D.; Tollefson, D.A.

    1991-01-01

    The purpose of Thermal Insulation Characterization Testing is to provide physical data to support certain assumptions and calculational techniques used in the criticality safety calculations in Section 6 of the Safety Analysis Reports for Packaging (SARPs) for drum-type packaging for Department of Energy's (DOE) Oak Ridge Y-12 Plant, managed by Martin Marietta Energy Systems, Inc. Results of preliminary data evaluation regarding the fire-test condition reveal that realistic weight loss consideration and residual material characterization in developing calculational models for the hypothetical accident condition is necessary in order to prevent placement of unduly conservative restrictions on shipping requirements as a result of overly conservative modeling. This is particularly important for fast systems. Determination of the geometric arrangement of residual material is of secondary importance. Both the methodology used to determine the minimum thermal insulation mass remaining after the fire test and the treatment of the thermal insulation in the criticality safety calculational models requires additional evaluation. Specific testing to be conducted will provide experimental data with which to validate the mass estimates and calculational modeling techniques for extrapolation to generic drum-type containers

  20. Facility for endurance tests of thermal insulations

    International Nuclear Information System (INIS)

    Mauersberger, R.

    1984-01-01

    In the following report the design and construction of an experimental facility for endurance tests of thermal insulations is presented. It's name in abbreviation is 'ADI' standing for the German words A nlage zum Dauertest von Isolierungen . This test facility was build by HRB in order to investigate the performance of thermal insulation systems of hot gas ducts for the process heat-reactor-project. The tests are intended to simulate the conditions of reactor operation. They include short-time experiments for selection of insulation-concepts and in a second step long-time experiments as performance tests. During these tests are measured the effective heat conductivity the local heat losses the temperature profiles of the insulation, of the fixing elements and along the wall of the duct. The design-data required to perform all these tasks are shown in the first picture: The gas-atmosphere must be Helium in tests like in reactor with regard to the special thermal and hydraulic properties of Helium and to the influence of Helium on mechanic friction and wear. The hot gas temperature in the PNP-reactor will be 950 deg. C and should be equal in the experiments. The temperature on the cold side of the insulation has to be adjustable from 50 deg. C up to 300 deg. C. The Helium pressure in the hot gas ducts of a HTR-plant is about 42 bar. The ADI was laid out for 70 bar to cover the hole range of interest. A Helium mass flow has to stream through the insulated test duct in order to realize equal temperatures on the hot side of the insulation. A flow rate of 4,5 kg/s is sufficient for this requirement. The axial pressure gradient along the insulation must be the same as in the reactor, because this has an essential influence on the heat losses. This pressure gradient is about 40 Pa/m

  1. Status of surface conduction in topological insulators

    International Nuclear Information System (INIS)

    Barua, Sourabh; Rajeev, K. P.

    2014-01-01

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

  2. High-voltage polymeric insulated cables

    Energy Technology Data Exchange (ETDEWEB)

    Ross, A

    1987-01-01

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

  3. Spray Foam Exterior Insulation with Stand-Off Furring

    Energy Technology Data Exchange (ETDEWEB)

    Herk, Anastasia [IBACOS, Inc., Pittsburgh, PA (United States); Baker, Richard [IBACOS, Inc., Pittsburgh, PA (United States); Prahl, Duncan [IBACOS, Inc., Pittsburgh, PA (United States)

    2014-03-01

    IBACOS, in collaboration with GreenHomes America, was contracted by the New York State Energy Research and Development Authority to research exterior wall insulation solutions. This research investigated cost-effective deep energy retrofit (DER) solutions for improving the building shell exterior while achieving a cost-reduction goal, including reduced labor costs to reach a 50/50 split between material and labor. The strategies included exterior wall insulation plus energy upgrades as needed in the attic, mechanical and ventilation systems, and basement band joist, walls, and floors. The work can be integrated with other home improvements such as siding or window replacement. This strategy minimizes physical connections to existing wall studs, encapsulates existing siding materials (including lead paint) with spray foam, and creates a vented rain screen assembly to promote drying. GreenHomes America applied construction details created by IBACOS to a test home. 2x4 framing members were attached to the wall at band joists and top plates using 'L' clips, with spray foam insulating the wall after framing was installed. Windows were installed simultaneously with the framing, including extension jambs. The use of clips in specific areas provided the best strength potential, and 'picture framing' the spray foam held the 2x4s in place. Short-term testing was performed at this house, with monitoring equipment installed for long-term testing. Testing measurements will be provided in a later report, as well as utility impact (before and after), costs (labor and materials), construction time, standard specifications, and analysis for the exterior wall insulation strategy.

  4. Spray Foam Exterior Insulation with Stand-Off Furring

    Energy Technology Data Exchange (ETDEWEB)

    Herk, Anatasia [IBACOS, Inc., Pittsburgh, PA (United States); Baker, Richard [IBACOS, Inc., Pittsburgh, PA (United States); Prahl, Duncan [IBACOS, Inc., Pittsburgh, PA (United States)

    2014-03-01

    IBACOS, in collaboration with GreenHomes America, was contracted by the New York State Energy Research and Development Authority to research exterior wall insulation solutions. This research investigated cost-effective deep energy retrofit (DER) solutions for improving the building shell exterior while achieving a cost-reduction goal, including reduced labor costs to reach a 50/50 split between material and labor. The strategies included exterior wall insulation plus energy upgrades as needed in the attic, mechanical and ventilation systems, and basement band joist, walls, and floors. The work can be integrated with other home improvements such as siding or window replacement. This strategy minimizes physical connections to existing wall studs, encapsulates existing siding materials (including lead paint) with spray foam, and creates a vented rain screen assembly to promote drying. GreenHomes America applied construction details created by IBACOS to a test home. 2x4 framing members were attached to the wall at band joists and top plates using "L" clips, with spray foam insulating the wall after framing was installed. Windows were installed simultaneously with the framing, including extension jambs. The use of clips in specific areas provided the best strength potential, and "picture framing" the spray foam held the 2x4s in place. Short-term testing was performed at this house, with monitoring equipment installed for long-term testing. Testing measurements will be provided in a later report, as well as utility impact (before and after), costs (labor and materials), construction time, standard specifications, and analysis for the exterior wall insulation strategy.

  5. Proximity effects in topological insulator heterostructures

    International Nuclear Information System (INIS)

    Li Xiao-Guang; Wu Guang-Fen; Zhang Gu-Feng; Culcer Dimitrie; Zhang Zhen-Yu; Chen Hua

    2013-01-01

    Topological insulators (TIs) are bulk insulators that possess robust helical conducting states along their interfaces with conventional insulators. A tremendous research effort has recently been devoted to Tl-based heterostructures, in which conventional proximity effects give rise to a series of exotic physical phenomena. This paper reviews our recent studies on the potential existence of topological proximity effects at the interface between a topological insulator and a normal insulator or other topologically trivial systems. Using first-principles approaches, we have realized the tunability of the vertical location of the topological helical state via intriguing dual-proximity effects. To further elucidate the control parameters of this effect, we have used the graphene-based heterostructures as prototypical systems to reveal a more complete phase diagram. On the application side of the topological helical states, we have presented a catalysis example, where the topological helical state plays an essential role in facilitating surface reactions by serving as an effective electron bath. These discoveries lay the foundation for accurate manipulation of the real space properties of the topological helical state in TI-based heterostructures and pave the way for realization of the salient functionality of topological insulators in future device applications. (topical review - low-dimensional nanostructures and devices)

  6. Topological insulators and superconductors from string theory

    International Nuclear Information System (INIS)

    Ryu, Shinsei; Takayanagi, Tadashi

    2010-01-01

    Topological insulators and superconductors in different spatial dimensions and with different discrete symmetries have been fully classified recently, revealing a periodic structure for the pattern of possible types of topological insulators and superconductors, both in terms of spatial dimensions and in terms of symmetry classes. It was proposed that K theory is behind the periodicity. On the other hand, D-branes, a solitonic object in string theory, are also known to be classified by K theory. In this paper, by inspecting low-energy effective field theories realized by two parallel D-branes, we establish a one-to-one correspondence between the K-theory classification of topological insulators/superconductors and D-brane charges. In addition, the string theory realization of topological insulators and superconductors comes naturally with gauge interactions, and the Wess-Zumino term of the D-branes gives rise to a gauge field theory of topological nature, such as ones with the Chern-Simons term or the θ term in various dimensions. This sheds light on topological insulators and superconductors beyond noninteracting systems, and the underlying topological field theory description thereof. In particular, our string theory realization includes the honeycomb lattice Kitaev model in two spatial dimensions, and its higher-dimensional extensions. Increasing the number of D-branes naturally leads to a realization of topological insulators and superconductors in terms of holography (AdS/CFT).

  7. Foam/Aerogel Composite Materials for Thermal and Acoustic Insulation and Cryogen Storage

    Science.gov (United States)

    Williams, Martha K. (Inventor); Smith, Trent M. (Inventor); Fesmire, James E. (Inventor); Weiser, Erik S. (Inventor); Sass, Jared P. (Inventor)

    2011-01-01

    The invention involves composite materials containing a polymer foam and an aerogel. The composite materials have improved thermal insulation ability, good acoustic insulation, and excellent physical mechanical properties. The composite materials can be used, for instance, for heat and acoustic insulation on aircraft, spacecraft, and maritime ships in place of currently used foam panels and other foam products. The materials of the invention can also be used in building construction with their combination of light weight, strength, elasticity, ability to be formed into desired shapes, and superior thermal and acoustic insulation power. The materials have also been found to have utility for storage of cryogens. A cryogenic liquid or gas, such as N.sub.2 or H.sub.2, adsorbs to the surfaces in aerogel particles. Thus, another embodiment of the invention provides a storage vessel for a cryogen.

  8. 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...... and polyethylene insulated Nickel-Chrome (NiCr) wires with inner core diameter of 0.50 mm and insulation thickness of 0.30 mm were examined with external flow velocities ranging from 50mm/s to 200mm/s. The results for the Copper wires show that with increasing external flow velocity, the LOC monotonically...... decreased for the concurrent flow conditions and the LOC first decreased and then increased (“U” trend) for the opposed flow conditions. Similar trends were found in the experiments with NiCr wires. Also, in terms of the minimum LOC value, the minimum LOC was comparable for both wire types in both flow...

  9. High-Performance Slab-on-Grade Foundation Insulation Retrofits

    Energy Technology Data Exchange (ETDEWEB)

    Goldberg, Louise F. [NorthernSTAR, St. Paul, MN (United States); Mosiman, Garrett E. [NorthernSTAR, St. Paul, MN (United States)

    2015-09-01

    A more accurate assessment of slab-on-grade foundation insulation energy savings than traditionally possible is now feasible. This has been enabled by advances in whole building energy simulation with 3-dimensional foundation modelling integration at each time step together with an experimental measurement of the site energy savings of SOG foundation insulation. Ten SOG insulation strategies were evaluated on a test building to identify an optimum retrofit insulation strategy in a zone 6 climate (Minneapolis, MN). The optimum insulation strategy in terms of energy savings and cost effectiveness consisted of two components: (a) R-20 XPS insulation above grade, and, (b) R-20 insulation at grade (comprising an outer layer of R-10 insulation and an interior layer of R-12 poured polyurethane insulation) tapering to R-10 XPS insulation at half the below-grade wall height (the lower half of the stem wall was uninsulated).

  10. Linear accelerator with x-ray absorbing insulators

    International Nuclear Information System (INIS)

    Rose, P.H.

    1975-01-01

    Annular insulators for supporting successive annular electrodes in a linear accelerator have embedded x-ray absorbing shield structures extending around the accelerating path. The shield members are disposed to intercept x-ray radiation without disrupting the insulative effect of the insulator members. In preferred forms, the structure comprises a plurality of annular members of heavy metal disposed in an x-ray blocking array, spaced from each other by the insulating substance of the insulator member. (auth)

  11. Development of insulating coatings for liquid metal blankets

    International Nuclear Information System (INIS)

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

    1994-07-01

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

  12. Biodegradation performance of environmentally-friendly insulating oil

    Science.gov (United States)

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

    2018-02-01

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

  13. Manipulating topological-insulator properties using quantum confinement

    International Nuclear Information System (INIS)

    Kotulla, M; Zülicke, U

    2017-01-01

    Recent discoveries have spurred the theoretical prediction and experimental realization of novel materials that have topological properties arising from band inversion. Such topological insulators are insulating in the bulk but have conductive surface or edge states. Topological materials show various unusual physical properties and are surmised to enable the creation of exotic Majorana-fermion quasiparticles. How the signatures of topological behavior evolve when the system size is reduced is interesting from both a fundamental and an application-oriented point of view, as such understanding may form the basis for tailoring systems to be in specific topological phases. This work considers the specific case of quantum-well confinement defining two-dimensional layers. Based on the effective-Hamiltonian description of bulk topological insulators, and using a harmonic-oscillator potential as an example for a softer-than-hard-wall confinement, we have studied the interplay of band inversion and size quantization. Our model system provides a useful platform for systematic study of the transition between the normal and topological phases, including the development of band inversion and the formation of massless-Dirac-fermion surface states. The effects of bare size quantization, two-dimensional-subband mixing, and electron–hole asymmetry are disentangled and their respective physical consequences elucidated. (paper)

  14. Application of mineral insulated cable (MIC) in Tokamak fusion reactor

    International Nuclear Information System (INIS)

    Luo Tianyong; Jiang Jiaming; Cen Yishun

    2014-01-01

    To avoid the instability of plasma and achieve some experimental tasks in Tokamak fusion reactor, many in-vessel coils are designed such as the coils to mitigate the effect of Edge Localized Modes (ELMs coils) and the coils to provide vertical stabilization (VS coils). The in-vessel location presents special challenges in terms of nuclear radiation and temperature, and requires the use of mineral-insulated conductors. The in-vessel coils in ITER are designed to be Mineral-insulated Cable (MIC) with three-layer structures. The inner is hollow-core tube made by OFHC or CuCrZr, the middle is the insulation layer made by Mgo and the outer is the jacket by SS316L or Inconel 718. To control the effect of Edge Localized Modes and vertical instability of plasma, the MIC in-vessel coils shall be used in HL-2M. More details about the application of MIC in Tokamak fusion reactor will be shown in this report. (authors)

  15. Quantum oscillations in insulators with neutral Fermi surfaces

    Science.gov (United States)

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

    2018-02-01

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

  16. Measure Guideline: Guidance on Taped Insulating Sheathing Drainage Planes

    Energy Technology Data Exchange (ETDEWEB)

    Grin, A.; Lstiburek, J.

    2014-09-01

    This guide provides information and recommendations to the following groups: insulation contractors; general contractors; builders; home remodelers; mechanical contractors; and homeowners, as a guide to the work that needs to be done. The order of work completed during home construction and retrofit improvements is important. Health and safety issues must be addressed first and are more important than durability issues. And durability issues are more important than saving energy. Not all techniques can apply to all houses. Special conditions will require special action. Some builders or homeowners will wish to do more than the important but basic retrofit strategies outlined by this guide. The following are best practice and product recommendations from the interviewed contractors and homebuilders who collectively have a vast amount of experience. Three significant items were discussed with the group which are required to make taped insulating sheathing a simple, long term, and durable drainage plane: 1. Horizontal joints should be limited or eliminated wherever possible; 2. Where a horizontal joint exists use superior materials; 3. Frequent installation inspection and regular trade training are required to maintain proper installation. Section 5 of this measure guideline contains the detailed construction procedure for the three recommended methods to effectively seal the joints in exterior insulating sheathing to create a simple, long term, and durable drainage plane.

  17. Spin-transfer torque generated by a topological insulator

    KAUST Repository

    Mellnik, A. R.

    2014-07-23

    Magnetic devices are a leading contender for the implementation of memory and logic technologies that are non-volatile, that can scale to high density and high speed, and that do not wear out. However, widespread application of magnetic memory and logic devices will require the development of efficient mechanisms for reorienting their magnetization using the least possible current and power. There has been considerable recent progress in this effort; in particular, it has been discovered that spin-orbit interactions in heavy-metal/ferromagnet bilayers can produce strong current-driven torques on the magnetic layer, via the spin Hall effect in the heavy metal or the Rashba-Edelstein effect in the ferromagnet. In the search for materials to provide even more efficient spin-orbit-induced torques, some proposals have suggested topological insulators, which possess a surface state in which the effects of spin-orbit coupling are maximal in the sense that an electron\\' s spin orientation is fixed relative to its propagation direction. Here we report experiments showing that charge current flowing in-plane in a thin film of the topological insulator bismuth selenide (Bi2Se3) at room temperature can indeed exert a strong spin-transfer torque on an adjacent ferromagnetic permalloy (Ni81Fe19) thin film, with a direction consistent with that expected from the topological surface state. We find that the strength of the torque per unit charge current density in Bi 2Se3 is greater than for any source of spin-transfer torque measured so far, even for non-ideal topological insulator films in which the surface states coexist with bulk conduction. Our data suggest that topological insulators could enable very efficient electrical manipulation of magnetic materials at room temperature, for memory and logic applications. © 2014 Macmillan Publishers Limited. All rights reserved.

  18. Numerical noise analysis for insulator of overhead transmission line

    Science.gov (United States)

    Zhang, Yulin; Chen, Yuwen; Huang, Yu

    2018-04-01

    As an important and complex issue in aero acoustic field, a lot of explorations have been devoted to the wind-induced noise. However, there is still lack of intensive investigations for aerodynamic noise in high-voltage transmission. The overhead transmission line system leads to serious occupational noise exposure in high wind-speed environment, and the noise can even injure the electricians in charge of insulator. By using computational fluid dynamics (CFD) which combined with computational aero acoustics (CAA), this paper predicts the noise generated by insulator of high voltage electricity transmission line which explores in wind environment. The simulation results indicate that the wind velocity, the assembly angle of the insulator and its ribs' distribution are the main contributory factors for the aerodynamic noise. Specifically, when wind velocity is greater than 15m/s, the alteration of noise is not sensitive to the wind velocity; furthermore, when the assembly angle increases from 0°to 60°, the noise decreases gradually, however, if the angle is happening to be 75°or 90°, it would be even greater than that at 0°. In order to inhibit the aerodynamic noise, it is necessary to control the flow blowing across the boundary of the insulator. Consequently, the result indicates that if the outermost rib is shorter than the second one, the noise reduced evidently. This information expects to provide useful help for the extremely suppression of aerodynamic noise, and also supply practical reference material for the design and application of overhead transmission line system.

  19. ON THE NEED TO INCREASE THE RELIABILITY OF LINEAR INSULATORS FOR DISTRIBUTION NETWORKS 10-20 KV

    Directory of Open Access Journals (Sweden)

    Yu. N. Shumilov

    2018-02-01

    Full Text Available Introduction. In Ukraine high voltage overhead distribution lines (OL of class 6 and 10 kV are the most extended. Their total length exceeds 280,000 km. More than 95% of the lines are made on line supports from reinforced concrete racks. On all poles of the overhead line, pin insulators are installed. According to the data of operation experience, up to 60-70% of single-phase earth (SPE faults due to «insulation» occurs on VL supports due to damage to line pin insulators, mainly during the thunderstorm period. Problem. Insufficient reliability of pin insulators leads to interruptions in power supply, accidents on the line, accidents in the area of reinforced concrete poles, where in the case of insulator damages, a long process of SPE occurs. Goal. The purpose of the work is to select the design and develop requirements for new linear insulators of 10-20 kV overhead lines that provide high resistance to lightning overvoltages with direct and inductive effects of lightning. Methodology. The research methodology consists in analyzing operational experience, calculating insulator parameters and laboratory tests. Results. Using statistical data on lightning parameters and data on mechanical loads on insulators, the main dimensions of line post insulators have been determined that will ensure their reliable operation under conditions of intense thunderstorm activity and extreme ice and wind loads. Conclusions. The main technical requirements for line post insulators for 10-20 kV distribution lines were formulated. On the 10 kV OL located in areas with increased thunderstorm activity it is recommended to use line post insulators instead of pin-type ones. On the OL-20 kV it is recommended to use only line post insulators. The use of high-lightning-resistant line post insulators on OL-10-20 kV will significantly increase the electrical safety and reliability of power supply to consumers. Increased by 2-3 times the cost of line post insulators in

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

    International Nuclear Information System (INIS)

    Mauger, R.A.; Goodings, A.

    1984-03-01

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

  1. INSUL, Calculation of Thermal Insulation of Various Materials Immersed in He

    International Nuclear Information System (INIS)

    Kinkead, A.N.; Pitchford, B.E.

    1977-01-01

    1 - Nature of the physical problem solved: Performance of thermal insulation immersed in helium. 2 - Method of solution: Mineral fibre, metal fibre and metallic multi-layer foils are studied. An approximate analysis for performance evaluation of multi-layer insulation in vertical gas spaces including the regime between fully suppressed natural convection and that for which an accepted power relationship applies is included

  2. The inaccuracy of heat transfer characteristics for non-insulated and insulated spherical containers neglecting the influence of heat radiation

    International Nuclear Information System (INIS)

    Wong, King-Leung; Salazar, Jose Luis Leon; Prasad, Leo; Chen, Wen-Lih

    2011-01-01

    In this investigation, the differences of heat transfer characteristics for insulated and non-insulated spherical containers between considering and neglecting the influence of heat radiation are studied by the simulations in some practical situations. It is found that the heat radiation effect cannot be ignored in conditions of low ambient convection heat coefficients (such ambient air) and high surface emissivities, especially for the non-insulated and thin insulated cases. In most practical situations when ambient temperature is different from surroundings temperature and the emissivity of insulation surface is different from that of metal wall surface, neglecting heat radiation will result in inaccurate insulation effect and heat transfer errors even with very thick insulation. However, the insulation effect considering heat radiation will only increase a very small amount after some dimensionless insulated thickness (such insulation thickness/radius ≥0.2 in this study), thus such dimensionless insulated thickness can be used as the optimum thickness in practical applications. Meanwhile, wrapping a material with low surface emissivity (such as aluminum foil) around the oxidized metal wall or insulation layer (always with high surface emissivity) can achieve very good insulated effect for the non-insulated or thin insulated containers.

  3. Using radio frequency and ultrasonic antennas for inspecting pin-type insulators on medium-voltage overhead distribution lines

    Directory of Open Access Journals (Sweden)

    Cícero Lefort Borges

    2013-05-01

    Full Text Available This paper summarises the activities undertaken when using antennas (ultrasound and radiofrequency for identifying insulators in pre-failure state by detecting the noise emitted by the distribution line and correlating this with these insulators (porcelain pin type dielectric breakdown. This has led to developing low-cost maintenance procedures and providing support and criteria for engineer-ing decisions regarding replacing these insulators. The technique used two detectors; a radio frequency detector was used in a first investigation of a particular distribution line, set to 40 MHz and installed on the roof of a moving vehicle. The ultrasound detector was used for inspecting (phases A, B, C each structure (pole selected. Atmospheric conditions had no influence on defining pre-failure insulators (pin type based on the noise detection technique. Pin type insulators emitting noise should be replaced since measurement was made from the ground and near the base of the post.

  4. Sensitization to Gliadin Induces Moderate Enteropathy and Insulitis in Nonobese Diabetic-DQ8 Mice

    Science.gov (United States)

    Galipeau, Heather J.; Rulli, Nestor E.; Jury, Jennifer; Huang, Xianxi; Araya, Romina; Murray, Joseph A.; David, Chella S.; Chirdo, Fernando G.; McCoy, Kathy D.; Verdu, Elena F.

    2012-01-01

    Celiac disease (CD) is frequently diagnosed in patients with type 1 diabetes (T1D), and T1D patients can exhibit Abs against tissue transglutaminase, the auto-antigen in CD. Thus, gliadin, the trigger in CD, has been suggested to have a role in T1D pathogenesis. The objective of this study was to investigate whether gliadin contributes to enteropathy and insulitis in NOD-DQ8 mice, an animal model that does not spontaneously develop T1D. Gliadin-sensitized NOD-DQ8 mice developed moderate enteropathy, intraepithelial lymphocytosis, and barrier dysfunction, but not insulitis. Administration of anti-CD25 mAbs before gliadin-sensitization induced partial depletion of CD25+Foxp3+ T cells and led to severe insulitis, but did not exacerbate mucosal dysfunction. CD4+ T cells isolated from pancreatic lymph nodes of mice that developed insulitis showed increased proliferation and proinflammatory cytokines after incubation with gliadin but not with BSA. CD4+ T cells isolated from nonsensitized controls did not response to gliadin or BSA. In conclusion, gliadin sensitization induced moderate enteropathy in NOD-DQ8 mice. However, insulitis development required gliadin-sensitization and partial systemic depletion of CD25+Foxp3+ T cells. This humanized murine model provides a mechanistic link to explain how the mucosal intolerance to a dietary protein can lead to insulitis in the presence of partial regulatory T cell deficiency. PMID:21911598

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

    International Nuclear Information System (INIS)

    Khamzakhan, G; Chaikovsky, S A

    2014-01-01

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

  6. Insulators form gene loops by interacting with promoters in Drosophila.

    Science.gov (United States)

    Erokhin, Maksim; Davydova, Anna; Kyrchanova, Olga; Parshikov, Alexander; Georgiev, Pavel; Chetverina, Darya

    2011-09-01

    Chromatin insulators are regulatory elements involved in the modulation of enhancer-promoter communication. The 1A2 and Wari insulators are located immediately downstream of the Drosophila yellow and white genes, respectively. Using an assay based on the yeast GAL4 activator, we have found that both insulators are able to interact with their target promoters in transgenic lines, forming gene loops. The existence of an insulator-promoter loop is confirmed by the fact that insulator proteins could be detected on the promoter only in the presence of an insulator in the transgene. The upstream promoter regions, which are required for long-distance stimulation by enhancers, are not essential for promoter-insulator interactions. Both insulators support basal activity of the yellow and white promoters in eyes. Thus, the ability of insulators to interact with promoters might play an important role in the regulation of basal gene transcription.

  7. Artificial heart system thermal insulation component development

    International Nuclear Information System (INIS)

    Svedberg, R.C.; Buckman, R.W. Jr.

    1975-01-01

    A concentric cup vacuum multifoil insulation system has been selected by virtue of its size, weight, and thermal performance to insulate the hot radioisotope portion of the thermal converter of an artificial implantable heart system. A factor of 2 improvement in thermal performance, based on the heat loss per number of foil layers (minimum system weight and volume) has been realized over conventional spiral wrapped multifoil vacuum insulation. This improvement is the result of the concentric cup construction to maintain a uniform interfoil spacing and the elimination of corner heat losses. Based on external insulation system dimensions (surface area in contact with host body), heat losses of 0.019 W/ cm 2 at 1140 0 K (1600 0 F) and 0.006 W/cm 2 at 920 0 K (1200 0 F) have been achieved. Factors which influence thermal performance of the nickel foil concentric cup insulation system include the number of cups, configuration and method of application of zirconia (ZrO 2 ) spacer material, system pressure, emittance of the cups, and operating temperature

  8. THE EFFICACY OF THE CABLES OF 6–110 KW WITH XLPE INSULATION. Part 2

    Directory of Open Access Journals (Sweden)

    M. A. Korotkevich

    2017-01-01

    Full Text Available The assessment of the suitability of cables of 6–110 kW with XLPE insulation in comparison with cables of the same voltage but possessing paper-oil insulation has been fulfilled on the basis of the method of multi-objective optimization that makes it possible to account not only the quantitative characteristics (of reduced costs, but also qualitative ones. As an indicator of the reliability of the cable line the maximum mean time to failure (the value inversely proportional to the parameter of succession of failures, which is an order more for cable lines with XLPE insulation than for cable lines with paper insulation, is adopted. A comprehensive assessment of the convenience of installation of cable lines revealed that the installation of cable with XLPE insulation features a 1.2–1.6 times easier installation as compared to three-wire (voltage 10 kW and 1.4 times easier installation as compared to single-core oil-filled cables (voltage of 110 kW. The efficacy of the cables 6–110 kW with XLPE insulation is proved on the basis on the method of multi-objective optimization, that took into account as the costs for the construction and operation of cable lines and the reliability of its operation, ease of its installation and other quality indicators. If the goals taken into account are considered as equally important, the polyethylene-insulated cables for a voltage of 10–110 kW is more efficient as compared to three-wire (voltage 10 kW and solid (110 kW cables with paper insulation. Herewith, the cost of the cable with XLPE insulation may exceed the cost of cable with paper insulation up to two times. If the most important aim is to provide the minimum reduced costs for the construction and operation of the cable line, the use of cables with XLPE insulation for voltage of 10 kW is most advisable in individual cases.

  9. Preparation Nano-Structure Polytetrafluoroethylene (PTFE Functional Film on the Cellulose Insulation Polymer and Its Effect on the Breakdown Voltage and Hydrophobicity Properties

    Directory of Open Access Journals (Sweden)

    Jian Hao

    2018-05-01

    Full Text Available Cellulose insulation polymer is an important component of oil-paper insulation, which is widely used in power transformer. The weight of the cellulose insulation polymer materials is as high as tens of tons in the larger converter transformer. Excellent performance of oil-paper insulation is very important for ensuring the safe operation of larger converter transformer. An effective way to improve the insulation and the physicochemical property of the oil impregnated insulation pressboard/paper is currently a popular research topic. In this paper, the polytetrafluoroethylene (PTFE functional film was coated on the cellulose insulation pressboard by radio frequency (RF magnetron sputtering to improve its breakdown voltage and the hydrophobicity properties. X-ray photoelectron spectroscopy (XPS results show that the nano-structure PTFE functional film was successfully fabricated on the cellulose insulation pressboard surface. The scanning electron microscopy (SEM and X-ray diffraction (XRD present that the nanoscale size PTFE particles were attached to the pressboard surface and it exists in the amorphous form. Atomic force microscopy (AFM shows that the sputtered pressboard surface is still rough. The rough PTFE functional film and the reduction of the hydrophilic hydroxyl of the surface due to the shielding effect of PTFE improve the breakdown and the hydrophobicity properties of the cellulose insulation pressboard obviously. This paper provides an innovative way to improve the performance of the cellulose insulation polymer.

  10. PD-pulse characteristics in rotating machine insulation

    DEFF Research Database (Denmark)

    Holbøll, Joachim; Henriksen, Mogens; Jensen, A

    1994-01-01

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

  11. Optimisation of Multilayer Insulation an Engineering Approach

    CERN Document Server

    Chorowski, M; Parente, C; Riddone, G

    2001-01-01

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

  12. Acoustic excitation of containment insulation cover plate

    International Nuclear Information System (INIS)

    Fenech, H.; Rao, A.K.

    1978-01-01

    An experimental and theoretical program has been implemented by NRC-BNL since 1975 at the University of California, Santa Barbara to assess the reliability of the PCRV thermal insulation cover plate and the possible safety problem caused by the failure of this plate. A typical large HTGR PCRV unit [1160 MW(e)] and thermal insulation class A were selected. The upper core cavity is estimated to be the most critical volume where the noise pressure levels are expected to reach 110 to 130 dB (rel. to 2 x 10 -4 dynes/cm 2 ). The noise spectrum in that cavity is a composite of circulator noise, vortex shedding boundary layer turbulence, and flow impingement. Some anticipated safety related problems associated with the thermal insulation failure are examined

  13. Acoustic quality and sound insulation between dwellings

    DEFF Research Database (Denmark)

    Rindel, Jens Holger

    1998-01-01

    to another, however, several of the results show a slope around 4 % per dB. The results may be used to evaluate the acoustic quality level of a certain set of sound insulation requirements, or they may be used as a basis for specifying the desired acoustic quality of future buildings......During the years there have been several large field investigations in different countries with the aim to find a relationship between sound insulation between dwellings and the subjective degree of annoyance. This paper presents an overview of the results, and the difficulties in comparing...... the different findings are discussed. It is tried to establish dose-response relationships between airborne sound insulation or impact sound pressure level according to ISO 717 and the percentage of people being annoyed by noise from neighbours. The slopes of the dose-response curves vary from one investigation...

  14. Acoustic quality and sound insulation between dwellings

    DEFF Research Database (Denmark)

    Rindel, Jens Holger

    1999-01-01

    to another, however, several of the results show a slope around 4 % per dB. The results may be used to evaluate the acoustic quality level of a certain set of sound insulation requirements, or they may be used as a basis for specifying the desired acoustic quality of future buildings.......During the years there have been several large field investigations in different countries with the aim to find a relationship between sound insulation between dwellings and the subjective degree of annoyance. This paper presents an overview of the results, and the dif-ficulties in comparing...... the different findings are discussed. It is tried to establish dose-response relationships between airborne sound insulation or impact sound pressure level according to ISO 717 and the percentage of people being annoyed by noise from neighbours. The slopes of the dose-response curves vary from one investigation...

  15. Insulating Foams Save Money, Increase Safety

    Science.gov (United States)

    2009-01-01

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

  16. HgTe based topological insulators

    International Nuclear Information System (INIS)

    Bruene, Christoph

    2014-01-01

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

  17. 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.

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

    Energy Technology Data Exchange (ETDEWEB)

    Althammer, Matthias Klaus

    2012-07-19

    /platinum heterostructures using two independent experiments based on the spin pumping effect. The yttrium iron garnet thin films were again deposited via laser-MBE and are state-of-the-art. Our results establish ferromagnetic insulator/normal metal structures as efficient spin current sources. Finally, we show that a new magnetoresistance effect due to spin currents is present in these ferromagnetic insulator/normal metal hybrids. This magnetoresistance effect in particular provides a simple means to establish spin current ow across the interface.

  19. High-fluence implantation in insulators. 1

    International Nuclear Information System (INIS)

    Mazzoldi, P.

    1989-01-01

    The defects which can be formed by ion implantation depend upon the insulator structure and composition. Thus, for glasses and ceramics, different changes are expected in mechanical and tribological properties, network dilatation, induced optical absorption and luminescence, compositional changes and modifications in the chemical behaviour. The modifications induced by ion implantation in the composition of glasses, with particular reference to alkali silicate glasses, the mechanical and tribological properties of ion implanted insulators, in particular glasses and ceramics, and the optical properties are discussed. 56 refs.; 20 figs

  20. Soup Cooking by Thermal Insulation Method

    OpenAIRE

    佐藤, 辰江; 根本, 勢子; サトウ, タツエ; ネモト, セイコ; TATSUE, SATO; SEIKO, NEMOTO

    1992-01-01

    In order to examine the thermal insulation method of soup cooking, we cooked two kinds of soup. The soup cooked by thermal insulation method was compared with the soup cooked by standard boiling method. ln sensory test, it was more aromatic and palatable than the soup by boiling, and some panels commented that it was rather mild. The measured values of pH, specific gravity, acidity and amount of dry weight of souble solids, total-N, formal-N of the soup cooked by the two methods mentioned abo...

  1. Radiant Heat Transfer in Reusable Surface Insulation

    Science.gov (United States)

    Hughes, T. A.; Linford, R. M. F.; Chmitt, R. J.; Christensen, H. E.

    1973-01-01

    During radiant testing of mullite panels, temperatures in the insulation and support structure exceeded those predicted on the basis of guarded hot plate thermal conductivity tests. Similar results were obtained during arc tunnel tests of mullite specimens. The differences between effective conductivity and guarded hot plate values suggested that radiant transfer through the mullite was occurring. To study the radiant transport, measurements were made of the infrared transmission through various insulating materials and fibers of interest to the shuttle program, using black body sources over the range of 780 to 2000 K. Experimental data were analyzed and scattering coefficients were derived for a variety of materials, fiber diameters, and source temperature.

  2. Three-dimensional topological insulators and bosonization

    Energy Technology Data Exchange (ETDEWEB)

    Cappelli, Andrea [INFN, Sezione di Firenze,Via G. Sansone 1, 50019 Sesto Fiorentino - Firenze (Italy); Randellini, Enrico [INFN, Sezione di Firenze,Via G. Sansone 1, 50019 Sesto Fiorentino - Firenze (Italy); Dipartimento di Fisica e Astronomia, Università di Firenze,Via G. Sansone 1, 50019 Sesto Fiorentino - Firenze (Italy); Sisti, Jacopo [Scuola Internazionale Superiore di Studi Avanzati (SISSA),Via Bonomea 265, 34136 Trieste (Italy)

    2017-05-25

    Massless excitations at the surface of three-dimensional time-reversal invariant topological insulators possess both fermionic and bosonic descriptions, originating from band theory and hydrodynamic BF theory, respectively. We analyze the corresponding field theories of the Dirac fermion and compactified boson and compute their partition functions on the three-dimensional torus geometry. We then find some non-dynamic exact properties of bosonization in (2+1) dimensions, regarding fermion parity and spin sectors. Using these results, we extend the Fu-Kane-Mele stability argument to fractional topological insulators in three dimensions.

  3. High Performance Slab-on-Grade Foundation Insulation Retrofits

    Energy Technology Data Exchange (ETDEWEB)

    Goldberg, Louise F. [NorthernSTAR, St. Paul, MN (United States); Mosiman, Garrett E. [NorthernSTAR, St. Paul, MN (United States)

    2015-09-01

    ?A more accurate assessment of SOG foundation insulation energy savings than traditionally possible is now feasible. This has been enabled by advances in whole building energy simulation with 3-dimensional foundation modelling integration at each time step together with an experimental measurement of the site energy savings of SOG foundation insulation. Ten SOG insulation strategies were evaluated on a test building to identify an optimum retrofit insulation strategy in a zone 6 climate (Minneapolis, MN). The optimum insulation strategy in terms of energy savings and cost effectiveness consisted of two components: (a) R-20 XPS insulation above grade, and, (b) R-20 insulation at grade (comprising an outer layer of R-10 insulation and an interior layer of R-12 poured polyurethane insulation) tapering to R-10 XPS insulation at half the below-grade wall height (the lower half of the stem wall was uninsulated). The optimum insulation strategy was applied to single and multi-family residential buildings in climate zone 4 - 7. The highest site energy savings of 5% was realized for a single family home in Duluth, MN, and the lowest savings of 1.4 % for a 4-unit townhouse in Richmond, VA. SOG foundation insulation retrofit simple paybacks ranged from 18 to 47 years. There are other benefits of SOG foundation insulation resulting from the increase in the slab surface temperatures. These include increased occupant thermal comfort, and a decrease in slab surface condensation particularly around the slab perimeter.

  4. Flexible edge seal for vacuum insulating glazing units

    Science.gov (United States)

    Bettger, Kenneth J.; Stark, David H.

    2012-12-11

    A flexible edge seal is provided for a vacuum insulating glazing unit having a first glass pane and a second glass pane spaced-apart from the first. The edge seal comprises a seal member formed of a hermetically bondable material and having a first end, a second end and a center section disposed therebetween. The first end is hermetically bondable to a first glass pane. The second end is hermetically bondable to a second glass pane. The center section comprises a plurality of convolutes.

  5. An insulating grid spacer for large-area MICROMEGAS chambers

    CERN Document Server

    Bernard, D; D'Enterria, D G; Le Guay, M; Martínez, G; Mora, M J; Pichot, P; Roy, D; Schutz, Y; Gandi, A; De Oliveira, R

    2002-01-01

    We present an original design for large area gaseous detectors based on the MICROMEGAS technology. This technology incorporates an insulating grid, sandwiched between the micro-mesh and the anode-pad plane, which provides an uniform 200 $\\mu$m amplification gap. The uniformity of the amplification gap thickness has been verified under several experimental conditions. The gain performances of the detector are presented and compared to the values obtained with detectors using cylindrical micro spacers. The new design presents several technical and financial advantages.

  6. Insulating Structural Ceramics Program, Final Report

    Energy Technology Data Exchange (ETDEWEB)

    Andrews, Mark J.; Tandon, Raj; Ott, Eric; Hind, Abi Akar; Long, Mike; Jensen, Robert; Wheat, Leonard; Cusac, Dave; Lin, H. T.; Wereszczak, Andrew A.; Ferber, Mattison K.; Lee, Sun Kun; Yoon, Hyung K.; Moreti, James; Park, Paul; Rockwood, Jill; Boyer, Carrie; Ragle, Christie; Balmer-Millar, Marilou; Aardahl, Chris; Habeger, Craig; Rappe, Ken; Tran, Diana; Koshkarian, Kent; Readey, Michael

    2005-11-22

    New materials and corresponding manufacturing processes are likely candidates for diesel engine components as society and customers demand lower emission engines without sacrificing power and fuel efficiency. Strategies for improving thermal efficiency directly compete with methodologies for reducing emissions, and so the technical challenge becomes an optimization of controlling parameters to achieve both goals. Approaches being considered to increase overall thermal efficiency are to insulate certain diesel engine components in the combustion chamber, thereby increasing the brake mean effective pressure ratings (BMEP). Achieving higher BMEP rating by insulating the combustion chamber, in turn, requires advances in material technologies for engine components such as pistons, port liners, valves, and cylinder heads. A series of characterization tests were performed to establish the material properties of ceramic powder. Mechanical chacterizations were also obtained from the selected materials as a function of temperature utilizing ASTM standards: fast fracture strength, fatique resistance, corrosion resistance, thermal shock, and fracture toughness. All ceramic materials examined showed excellent wear properties and resistance to the corrosive diesel engine environments. The study concluded that the ceramics examined did not meet all of the cylinder head insert structural design requirements. Therefore we do not recommend at this time their use for this application. The potential for increased stresses and temperatures in the hot section of the diesel engine combined with the highly corrosive combustion products and residues has driven the need for expanded materials capability for hot section engine components. Corrosion and strength requirements necessitate the examination of more advanced high temperture alloys. Alloy developments and the understanding of processing, structure, and properties of supperalloy materials have been driven, in large part, by the gas

  7. Using microtherm microporous insulation in smelter applications

    Science.gov (United States)

    MacKenzie, Iain

    2000-02-01

    Microtherm is effective in reducing shell temperatures in confined spaces where compression is severe and much insulation is required. This material can prove beneficial for applications such as cement and lime rotary kiln transition and hot zones; copper converters and anode furnaces; steel and iron ladles, tundishes, RH vessels, and blast furnaces; and aluminum filter boxes, runners, and metal transporters.

  8. Mineral insulated cables for post accident service

    International Nuclear Information System (INIS)

    McMillin, P.L.; Winkler, M.E.

    1986-01-01

    The regulatory requirement to measure the gamma radiation levels during accident conditions inside a reactor containment building is discussed. The development of a mineral-insulated cable and connector system to accurately transmit this measurement is described and a model of the response is developed

  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. Synthesis and characterization of innovative insulation materials

    Directory of Open Access Journals (Sweden)

    Skaropoulou Aggeliki

    2018-01-01

    Full Text Available Insulation elements are distinguished in inorganic fibrous and organic foamed materials. Foamed insulation materials are of great acceptance and use, but their major disadvantage is their flammability. In case of fire, they tend to transmit the flame producing toxic gases. In this paper, the synthesis and characterization of innovative inorganic insulation materials with properties competitive to commercial is presented. Their synthesis involves the mixing of inorganic raw material and water with reinforcing agent or/and foaming agent leading to the formation of a gel. Depending on raw materials nature, the insulation material is produced by freeze drying or ambient drying techniques of the gel. The raw material used are chemically benign and abundantly available materials, or industrial by-products and the final products are non-toxic and, in some cases, non-flammable. Their density and thermal conductivity was measured and found 0.02-0.06 g/cm3 and 0.03-0.04 W/mK, respectively.

  11. Insulating materials resistance in intense radiation beams

    International Nuclear Information System (INIS)

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

    2002-01-01

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

  12. Light fireproof insulating plate-formed material

    Energy Technology Data Exchange (ETDEWEB)

    Plum, B.A.; Juhl, L.F.

    1981-02-23

    Light fireproof insulating plates were produced by pressure processing of a mixture of rice-husk ashes with pearlite aluminium phosphate and glass wool. The corn size of pearlite is 0-5 mm., of rice-husk ashes 0-5 mm. and the fiber length of fibrous additive is about 25 mm.

  13. Insulating jacket for heat sensitive components

    International Nuclear Information System (INIS)

    Class, G.

    1980-01-01

    The insulating jacket for long core components of sodium-cooled reactors consists of several layers of austenitic steel, between which a woven wire mesh of the same material is fitted. It is wound in the form of a spiral bandage on the core component. (DG) [de

  14. Topics in magnetism: magnetic excitations in insulators

    International Nuclear Information System (INIS)

    Rezende, S.M.

    1975-01-01

    The concept of spin waves is introduced and green's functions formalism is used in connection with thermodynamic properties of ferromagnets. Simple features of magnons in ferromagnetic insulators are discussed and also of those with dipolar and anisotropic contributions in the hamiltonian. Magnons in more complex systems, e.g. antiferromagnetic crystals, are dealt with. Finally, excitation and detection of magnons are also discussed [pt

  15. 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.

  16. Electrical machining method of insulating ceramics

    International Nuclear Information System (INIS)

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

    1999-01-01

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

  17. Power flow studies of magnetically insulated lines

    International Nuclear Information System (INIS)

    McDaniel, D.H.; Poukey, J.W.; Bergeron, K.D.; VanDevender, J.P.; Johnson, D.L.

    1977-01-01

    The designs for relativistic electron beam accelerators with power levels of 20 to 100 TW are greatly restricted by the inductance of a single diode of reasonable size. This fact leads to modular designs of very large accelerators. One concept uses several small insulators at a large radius arranged around the accelerator center. The total effective inductance is then low, but the energy must then be transported by self-magnetic insulated vacuum lines to the target volume. A triplate vacuum line configuration eases many mechanical support problems and allows more A-K gaps or feeds to be packaged around a given radius. This type of vacuum transmission line was chosen for initial experiments at Sandia. The experiments were conducted on the MITE (Magnetically Insulated Transmission Experiment) accelerator. The water pulse forming lines are connected to a vacuum triplate line through a conventional stacked insulator. Diagnostics on the experiment consisted of: (1) input V; (2) input I; (3) I monitors at the input, middle, and output of both the center conductor and ground plane of the transmission line; (4) magnetic energy analyzer to view peak electron energy in the A-K gap; (5) calorimetry; and (6) Faraday cups to look at electron current flowing across the transmission line. The main goal of the experiment is to obtain input impedance of the transmission line as a function of voltage and to measure electron loss currents. These measurements are compared to theoretical models for the input impedance and energy losses

  18. Infrared circular photogalvanic effect in topological insulators

    Science.gov (United States)

    Luo, Siyuan

    2018-04-01

    Topological insulators have attracted a lot of attention in recent years due to its unique phenomena. Circular photogalvanic effect (CPGE) is one of the important phenomena in topological insulators. Bi2Se3, as one of the 3D topological insulators, consist of a single Dirac cone at the Γ point in k-space [1], corresponding to the surface states. Controlled by the Berry curvature of the surface band, the dominant photo response due to the interband transition is helicity dependent [2]. In addition, due to the spin-momentum locking in topological insulators' surface, the sign of spin-angular-momentum of obliquely incident light and photo currents are locked together. On the other hand, Bi2Se3 consists of quintuple layers which make it possible to be exfoliated and transferred based on graphene fabrication. In this paper, Bi2Se3 devices were fabricated and Ohm contact was achieved. We experimentally demonstrated the CPGE in Bi2Se3 using 1550nm incident laser.

  19. A Seismic Analysis for Reflective Metal Insulation

    International Nuclear Information System (INIS)

    Kim, Kyuhyung; Kim, Taesoon

    2016-01-01

    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

  20. Sound insulation requirements in the Nordic countries

    DEFF Research Database (Denmark)

    Rasmussen, Birgit

    All Nordic countries have sound insulation requirements for housing and sound classification schemes originating from a common INSTA‐proposal in the mid 90’s, but unfortunately being increasingly diversified since then. The present situation impedes development and create barriers for trade and e...

  1. Labeling and advertising of home insulation. Final staff report to the Federal Trade Commission and proposed trade regulation rule (16 CFR Part 460)

    Energy Technology Data Exchange (ETDEWEB)

    1978-07-01

    Insulation can save significant amounts of fuel and money, and has therefore captured public attention as a desirable energy conservation measure. Because insulation is a very difficult product for uninformed consumers to evaluate, there was broad support for a rule requiring the disclosure of information facilitating choices among insulation products. With the information that the Recommended Rule will require, consumers will be able to compare the thermal properties of varous types of insulation and make the best purchases for their needs. In order to provide consumers, as quickly as possible, with information aiding their purchase of this major conservation measure, and to protect consumers from the abuses that rising demand has brought, the Commission undertook this rulemaking proceeding on an expedited schedule. The Rule was proposed on November 18, 1977. The tests mandated by the Rule will provide reproducible and accurate R-values, permitting comparisons of thermal performance. As a result of the testing and required disclosures of R-values and related information, consumers should be able to make sound choices for their needs, without being uninformed or misinformed about the relative values of different types of insulation. The Recommended Rule covers the testing, advertising, and labeling of thermal insulation products. It includes organic, fibrous, cellular, and reflective insulations sold for use in homes, apartments, and other residential dwellings. Insulation sold directly to consumers for do-it-yourself installation is covered, as well as insulation installed by professionals.

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

    Science.gov (United States)

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

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

  3. Attic Retrofits Using Nail-Base Insulated Panels

    Energy Technology Data Exchange (ETDEWEB)

    Mallay, David [Home Innovation Research Labs; Kochkin, Vladimir [Home Innovation Research Labs

    2018-03-26

    This project developed and demonstrated a roof/attic energy retrofit solution using nail-base insulated panels for existing homes where traditional attic insulation approaches are not effective or feasible. Nail-base insulated panels (retrofit panels) consist of rigid foam insulation laminated to one face of a wood structural panel. The prefabricated panels are installed above the existing roof deck during a reroofing effort.

  4. A Literature Review of Sealed and Insulated Attics—Thermal, Moisture and Energy Performance

    Energy Technology Data Exchange (ETDEWEB)

    Less, Brennan [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Walker, Iain [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Levinson, Ronnen [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)

    2016-08-01

    In this literature review and analysis, we focus on the thermal, moisture and energy performance of sealed and insulated attics in California climates. Thermal. Sealed and insulated attics are expected to maintain attic air temperatures that are similar to those in the house within +/- 10°F. Thermal stress on the assembly, namely high shingle and sheathing temperatures, are of minimal concern. In the past, many sealed and insulated attics were constructed with insufficient insulation levels (~R-20) and with too much air leakage to outside, leading to poor thermal performance. To ensure high performance, sealed and insulated attics in new California homes should be insulated at levels at least equivalent to the flat ceiling requirements in the code, and attic envelopes and ducts should be airtight. We expect that duct systems in well-constructed sealed and insulated attics should have less than 2% HVAC system leakage to outside. Moisture. Moisture risk in sealed and insulated California attics will increase with colder climate regions and more humid outside air in marine zones. Risk is considered low in the hot-dry, highly populated regions of the state, where most new home construction occurs. Indoor humidity levels should be controlled by following code requirements for continuous whole-house ventilation and local exhaust. Pending development of further guidance, we recommend that the air impermeable insulation requirements of the International Residential Code (2012) be used, as they vary with IECC climate region and roof finish. Energy. Sealed and insulated attics provide energy benefits only if HVAC equipment is located in the attic volume, and the benefits depend strongly on the insulation and airtightness of the attic and ducts. Existing homes with leaky, uninsulated ducts in the attic should have major savings. When compared with modern, airtight duct systems in a vented attic, sealed and insulated attics in California may still provide substantial benefit

  5. Spray-On Foam Insulations for Launch Vehicle Cryogenic Tanks

    Science.gov (United States)

    Fesmire, J. E.; Cofman, B. E.; Menghelli, B. J.; Heckle, K. W.

    2011-01-01

    Spray-on foam insulation (SOFI) has been developed for use on the cryogenic tanks of space launch vehicles beginning in the 1960s with the Apollo program. The use of SOFI was further developed for the Space Shuttle program. The External Tank (ET) of the Space Shuttle, consisting of a forward liquid oxygen tank in line with an aft liquid hydrogen tank, requires thermal insulation over its outer surface to prevent ice formation and avoid in-flight damage to the ceramic tile thermal protection system on the adjacent Orbiter. The insulation also provides system control and stability with throughout the lengthy process of cooldown, loading, and replenishing the tank. There are two main types of SOFI used on the ET: acreage (with the rind) and closeout (machined surface). The thermal performance of the seemingly simple SOFI system is a complex of many variables starting with the large temperature difference of from 200 to 260 K through the typical 25-mm thickness. Environmental factors include air temperature and humidity, wind speed, solar exposure, and aging or weathering history. Additional factors include manufacturing details, launch processing operations, and number of cryogenic thermal cycles. The study of the cryogenic thermal performance of SOFI under large temperature differentials is the subject of this article. The amount of moisture taken into the foam during the cold soak phase, termed Cryogenic Moisture Uptake, must also be considered. The heat leakage rates through these foams were measured under representative conditions using laboratory standard liquid nitrogen boiloff apparatus. Test articles included baseline, aged, and weathered specimens. Testing was performed over the entire pressure range from high vacuum to ambient pressure. Values for apparent thermal conductivity and heat flux were calculated and compared with prior data. As the prior data of record was obtained for small temperature differentials on non-weathered foams, analysis of the

  6. Spray-on foam insulations for launch vehicle cryogenic tanks

    Science.gov (United States)

    Fesmire, J. E.; Coffman, B. E.; Meneghelli, B. J.; Heckle, K. W.

    2012-04-01

    Spray-on foam insulation (SOFI) has been developed for use on the cryogenic tanks of space launch vehicles beginning in the 1960s with the Apollo program. The use of SOFI was further developed for the Space Shuttle program. The External Tank (ET) of the Space Shuttle, consisting of a forward liquid oxygen tank in line with an aft liquid hydrogen tank, requires thermal insulation over its outer surface to prevent ice formation and avoid in-flight damage to the ceramic tile thermal protection system on the adjacent Orbiter. The insulation also provides system control and stability throughout the lengthy process of cooldown, loading, and replenishing the tank. There are two main types of SOFI used on the ET: acreage (with the rind) and closeout (machined surface). The thermal performance of the seemingly simple SOFI system is a complex array of many variables starting with the large temperature difference of 200-260 K through the typical 25-mm thickness. Environmental factors include air temperature and humidity, wind speed, solar exposure, and aging or weathering history. Additional factors include manufacturing details, launch processing operations, and number of cryogenic thermal cycles. The study of the cryogenic thermal performance of SOFI under large temperature differentials is the subject of this article. The amount of moisture taken into the foam during the cold soak phase, termed Cryogenic Moisture Uptake, must also be considered. The heat leakage rates through these foams were measured under representative conditions using laboratory standard liquid nitrogen boiloff apparatus. Test articles included baseline, aged, and weathered specimens. Testing was performed over the entire pressure range from high vacuum to ambient pressure. Values for apparent thermal conductivity and heat flux were calculated and compared with prior data. As the prior data of record was obtained for small temperature differentials on non-weathered foams, analysis of the different

  7. On-surface synthesis on a bulk insulator surface

    Science.gov (United States)

    Richter, Antje; Floris, Andrea; Bechstein, Ralf; Kantorovich, Lev; Kühnle, Angelika

    2018-04-01

    On-surface synthesis has rapidly emerged as a most promising approach to prepare functional molecular structures directly on a support surface. Compared to solution synthesis, performing chemical reactions on a surface offers several exciting new options: due to the absence of a solvent, reactions can be envisioned that are otherwise not feasible due to the insolubility of the reaction product. Perhaps even more important, the confinement to a two-dimensional surface might enable reaction pathways that are not accessible otherwise. Consequently, on-surface synthesis has attracted great attention in the last decade, with an impressive number of classical reactions transferred to a surface as well as new reactions demonstrated that have no classical analogue. So far, the majority of the work has been carried out on conducting surfaces. However, when aiming for electronic decoupling of the resulting structures, e.g. for the use in future molecular electronic devices, non-conducting surfaces are highly desired. Here, we review the current status of on-surface reactions demonstrated on the (10.4) surface of the bulk insulator calcite. Besides thermally induced C-C coupling of halogen-substituted aryls, photochemically induced [2  +  2] cycloaddition has been proven possible on this surface. Moreover, experimental evidence exists for coupling of terminal alkynes as well as diacetylene polymerization. While imaging of the resulting structures with dynamic atomic force microscopy provides a direct means of reaction verification, the detailed reaction pathway often remains unclear. Especially in cases where the presence of metal atoms is known to catalyze the corresponding solution chemistry reaction (e.g. in the case of the Ullmann reaction), disclosing the precise reaction pathway is of importance to understand and generalize on-surface reactivity on a bulk insulator surface. To this end, density-functional theory calculations have proven to provide atomic

  8. Building America Best Practices Series. Volume 17 - Energy Renovations-Insulation: A Guide for Contractors to Share With Homeowners

    Energy Technology Data Exchange (ETDEWEB)

    Baechler, Michael C. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Adams, K. T. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Hefty, M. G. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Gilbride, T. L. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Love, Pat M. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)

    2012-05-01

    This guide will help contractors and homeowners identify ways to make their homes more comfortable, more energy efficient, and healthier to live in. It also identifies the steps to take, with the help of a qualified home performance contractor, to increase their home’s insulation, ensure healthy levels of ventilation, and prevent moisture problems. Contractors can use this document to explain the value of these insulation measures to their customers. The references in this document provide further explanation of insulation techniques and technologies.

  9. A low frequency acoustic insulator by using the acoustic metasurface to a Helmholtz resonator

    Directory of Open Access Journals (Sweden)

    Xiang Zhao

    2017-06-01

    Full Text Available Acoustic metasurfaces (AMSs are able to manipulate wavefronts at an anomalous angle through a subwavelength layer. Their application provide a new way to control sound waves in addition to traditional materials. In this work, we introduced the AMS into the design of a Helmholtz resonator (HR and studied the acoustic transmission through the modified HR in a pipe with one branch. The variation of sound insulation capacity with the phase gradient of the AMS was studied, and the results show that the AMS can remarkably lower the frequency band of the sound insulation without increasing the size. Our investigation provides a new degree of freedom for acoustic control with a Helmholtz resonator, which is of great significance in acoustic metasurface theory and sound insulation design.

  10. Recent Advances in the Sound Insulation Properties of Bio-based Materials

    Directory of Open Access Journals (Sweden)

    Xiaodong Zhu

    2013-12-01

    Full Text Available Many bio-based materials, which have lower environmental impact than traditional synthetic materials, show good sound absorbing and sound insulation performances. This review highlights progress in sound transmission properties of bio-based materials and provides a comprehensive account of various multiporous bio-based materials and multilayered structures used in sound absorption and insulation products. Furthermore, principal models of sound transmission are discussed in order to aid in an understanding of sound transmission properties of bio-based materials. In addition, the review presents discussions on the composite structure optimization and future research in using co-extruded wood plastic composite for sound insulation control. This review contributes to the body of knowledge on the sound transmission properties of bio-based materials, provides a better understanding of the models of some multiporous bio-based materials and multilayered structures, and contributes to the wider adoption of bio-based materials as sound absorbers.

  11. A low frequency acoustic insulator by using the acoustic metasurface to a Helmholtz resonator

    Science.gov (United States)

    Zhao, Xiang; Cai, Li; Yu, Dianlong; Lu, Zhimiao; Wen, Jihong

    2017-06-01

    Acoustic metasurfaces (AMSs) are able to manipulate wavefronts at an anomalous angle through a subwavelength layer. Their application provide a new way to control sound waves in addition to traditional materials. In this work, we introduced the AMS into the design of a Helmholtz resonator (HR) and studied the acoustic transmission through the modified HR in a pipe with one branch. The variation of sound insulation capacity with the phase gradient of the AMS was studied, and the results show that the AMS can remarkably lower the frequency band of the sound insulation without increasing the size. Our investigation provides a new degree of freedom for acoustic control with a Helmholtz resonator, which is of great significance in acoustic metasurface theory and sound insulation design.

  12. Spin currents and magnon dynamics in insulating magnets

    Science.gov (United States)

    Nakata, Kouki; Simon, Pascal; Loss, Daniel

    2017-03-01

    Nambu-Goldstone theorem provides gapless modes to both relativistic and nonrelativistic systems. The Nambu-Goldstone bosons in insulating magnets are called magnons or spin-waves and play a key role in magnetization transport. We review here our past works on magnetization transport in insulating magnets and also add new insights, with a particular focus on magnon transport. We summarize in detail the magnon counterparts of electron transport, such as the Wiedemann-Franz law, the Onsager reciprocal relation between the Seebeck and Peltier coefficients, the Hall effects, the superconducting state, the Josephson effects, and the persistent quantized current in a ring to list a few. Focusing on the electromagnetism of moving magnons, i.e. magnetic dipoles, we theoretically propose a way to directly measure magnon currents. As a consequence of the Mermin-Wagner-Hohenberg theorem, spin transport is drastically altered in one-dimensional antiferromagnetic (AF) spin-1/2 chains; where the Néel order is destroyed by quantum fluctuations and a quasiparticle magnon-like picture breaks down. Instead, the low-energy collective excitations of the AF spin chain are described by a Tomonaga-Luttinger liquid (TLL) which provides the spin transport properties in such antiferromagnets some universal features at low enough temperature. Finally, we enumerate open issues and provide a platform to discuss the future directions of magnonics.

  13. Spin currents and magnon dynamics in insulating magnets

    International Nuclear Information System (INIS)

    Nakata, Kouki; Loss, Daniel; Simon, Pascal

    2017-01-01

    Nambu–Goldstone theorem provides gapless modes to both relativistic and nonrelativistic systems. The Nambu–Goldstone bosons in insulating magnets are called magnons or spin-waves and play a key role in magnetization transport. We review here our past works on magnetization transport in insulating magnets and also add new insights, with a particular focus on magnon transport. We summarize in detail the magnon counterparts of electron transport, such as the Wiedemann–Franz law, the Onsager reciprocal relation between the Seebeck and Peltier coefficients, the Hall effects, the superconducting state, the Josephson effects, and the persistent quantized current in a ring to list a few. Focusing on the electromagnetism of moving magnons, i.e. magnetic dipoles, we theoretically propose a way to directly measure magnon currents. As a consequence of the Mermin–Wagner–Hohenberg theorem, spin transport is drastically altered in one-dimensional antiferromagnetic (AF) spin-1/2 chains; where the Néel order is destroyed by quantum fluctuations and a quasiparticle magnon-like picture breaks down. Instead, the low-energy collective excitations of the AF spin chain are described by a Tomonaga–Luttinger liquid (TLL) which provides the spin transport properties in such antiferromagnets some universal features at low enough temperature. Finally, we enumerate open issues and provide a platform to discuss the future directions of magnonics. (paper)

  14. Effects of radiation on insulation materials

    International Nuclear Information System (INIS)

    Poehlchen, R.

    1992-01-01

    This presentation will concentrate on the insulation materials which are suitable for the insulation of superconducting magnets for fusion. For the next generation of fusion machines with magnetic confinement as NET and ITER general agreement exists that the insulation will consist of fibre reinforced organic matrix material, a composite. Much effort has been put into the investigation of the radiation resistance of such materials during the last 20-30 years, see in particular the numerous reports of accelerator laboratories on this subject. But very few of the published data are relevant for the superconducting magnets of fusion machines. Either the irradiation and testing was carried out at RT or LN 2 temperature and/or the irradiation spectrum was not representative for a fusion machine and/or the materials investigated are not applicable for the insulation of S.C. fusion magnets. Therefore test programs have been launched recently, one by the NET team. The intention of the first chapter is to give guidance on the choice of materials which are suitable as insulation materials from a more general point of view. A good understanding of the coil manufacturing process is needed for this purpose. The second chapter explains the irradiation spectrum seen by the magnets. A third chapter does present the NET/ITER test programme. Step 1 was completed at the end of 1989, the second step will be carried out in the autumn of 1991. Finally, a general assessment of materials and testing methods will be given with recommendations for further testing

  15. Field evaluation of reflective insulation in south east Asia

    Science.gov (United States)

    Teh, Khar San; Yarbrough, David W.; Lim, Chin Haw; Salleh, Elias

    2017-12-01

    The objective of this research was to obtain thermal performance data for reflective insulations in a South East Asia environment. Thermal resistance data (RSI, m2 ṡ K/W) for reflective insulations are well established from 1-D steady-state tests, but thermal data for reflective insulation in structures like those found in South East Asia are scarce. Data for reflective insulations in South East Asia will add to the worldwide database for this type of energy-conserving material. RSI were obtained from heat flux and temperature data of three identical structures in the same location. One unit did not have insulation above the ceiling, while the second and third units were insulated with reflective insulation with emittance less than 0.05. RSI for the uninsulated test unit varied from 0.37 to 0.40 m2 ṡ K/W. RSI for a single-sheet reflective insulation (woven foil) varied from 2.15 to 2.26 m2 ṡ K/W, while bubble-foil insulation varied from 2.69 to 3.09 m2 ṡ K/W. The range of RSI values resulted from differences in the spacing between the reflective insulation and the roof. In addition, the reflective insulation below the roof lowered attic temperatures by as much as 9.7° C. Reductions in ceiling heat flux of 80 to 90% relative to the uninsulated structure, due to the reflective insulation, were observed.

  16. 49 CFR 236.527 - Roadway element insulation resistance.

    Science.gov (United States)

    2010-10-01

    ... 49 Transportation 4 2010-10-01 2010-10-01 false Roadway element insulation resistance. 236.527 Section 236.527 Transportation Other Regulations Relating to Transportation (Continued) FEDERAL RAILROAD... element insulation resistance. Insulation resistance between roadway inductor and ground shall be...

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

    International Nuclear Information System (INIS)

    Cui Yimin; Pan Wanjiang; Wu Songtao; Wan Yuanxi

    2003-01-01

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

  18. Quality labels for retrofit cavity wall insulation : a comparative analysis

    NARCIS (Netherlands)

    Rovers, Twan Johannes Hendrikus; Entrop, Alexis Gerardus; Halman, Johannes I.M.

    2017-01-01

    Retrofit cavity wall insulation can be exerted to reduce the energy use for space heating and cooling of existing buildings. In multiple countries, quality labels have emerged for this insulation service. In this research project, an evaluation framework for cavity wall insulation is developed by

  19. Study of the degradation of the insulation of HV cables with PVC insulation

    International Nuclear Information System (INIS)

    Quennehen, Pierre

    2014-01-01

    The observed decrease in the resistivity of the PVC insulation of some high voltage unipolar cables led to question their ability to perform their function. Provide answers concerning in particular the origin of the variation in resistivity and the impact on the dielectric strength were the objectives of this study. The characterizations were carried on cables withdrawn from service whose properties had changed during their use. Physico-chemical characterization (IR microscopy, UV spectroscopy, SEM - EDX and coulometry) showed that aging of the cable resulted from a mechanism of dehydro-chlorination. The presence of two modes of electric conduction in the material was observed: electronic conduction at a low temperature (≤ -10 C) and ionic conduction at room temperature and beyond. The presence of these two modes of conduction is consistent with the mechanism of dehydro-chlorination. In contrast to an Arrhenius law, artificial aging showed a threshold effect in the thermal activation of the mechanism at the origin of the resistivity drop. The dielectric strength of the cable has been confirmed by tests at voltages or temperatures well beyond the nominal values. Measurements of differential scanning calorimetry (DSC) showed occasional more or less pronounced over-heatings that correlate with the resistivity drops, and can therefore be considered as being at the origin of the observed evolutions. (author)

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2013-01-15

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

  1. Reactor potential of the magnetically insulated inertial fusion (MICF) system

    International Nuclear Information System (INIS)

    Kammash, T.; Galbraith, D.L.

    1987-01-01

    The Magnetically Insulated Inertial Confinement Fusion (MICF) scheme is examined with regard to its potential as a power-producing reactor. This approach combines the favorable aspects of both magnetic and inertial fusions in that physical containment of the plasma is provided by a metallic shell while thermal insulation of its energy is provided by a strong, self-generated magnetic field. The plasma is created at the core of the target as a result of irradiation of the fuel-coated inner surface by a laser beam that enters through a hole in the spherical shell. The instantaneous magnetic field is generated by the current loops formed by the laser-heated, laser-ablated electrons, and preliminary experimental results at Osaka University have confirmed the presence of such a field. These same experiments have also yielded a Lawson parameter of about 5x10 12 cm -3 sec, and because of these unique properties, the plasma lifetimes in MICF have been shown to be about two orders of magnitude longer than conventional, pusher type inertial fusion schemes. In this paper a quasi one dimensional, time dependent set of particle and energy balance equations for the thermal species, namely, electrons, ions and thermal alphas which also allows for an appropriate set of fast alpha groups is utilized to assess the reactor prospects of a DT-burning MICF system. (author) [pt

  2. Process for manufacture of Te microwire in glass insulation

    International Nuclear Information System (INIS)

    Bodiul, Pavel; Nicolaeva, Alibina; Konopko, Leonid; Bondarciuc, Nicolae

    2010-01-01

    The invention relates to the manufacturing of microwires in glass insulation and can be used in electronics and in the manufacturing of thermoelectrodes for thermoelectric sensors. The process for manufacture of Te microwire in glass insulation consists in softening the Te sample and its pulling in glass insulation. Near the microwire pulling zone through the furnace is maintained a temperature of 430-440 degrees Celsius, which causes the solidification firstly of Te microwire, and then of glass insulation. The result of the invention is to obtain Te microwires in glass insulation of high quality with a diameter of 50-100 μm and a length of 3-15 cm.

  3. High-performance insulator structures for accelerator applications

    International Nuclear Information System (INIS)

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

    1997-05-01

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

  4. Simulation of a two-dimensional sheath over a flat insulator-conductor interface on a radio-frequency biased electrode in a high-density plasma

    International Nuclear Information System (INIS)

    Kim, Doosik; Economou, Demetre J.

    2004-01-01

    A combined fluid/Monte Carlo (MC) simulation was developed to study the two-dimensional (2D) sheath over a flat insulator/conductor interface on a radio-frequency (rf) biased electrode in a high-density plasma. The insulator capacitance increased the local impedance between the plasma and the bias voltage source. Thus, for uniform ion density and electron temperature far away from the wall, the sheath potential over the insulator was only a fraction of that over the conductor, resulting in a thinner sheath over the insulator. The fluid model provided the spatiotemporal profiles of the 2D sheath electric field. These were used as input to the MC simulation to compute the ion energy distribution (IED) and ion angular distribution (IAD) at different locations on the surface. The ion flux, IED, and IAD changed drastically across the insulator/conductor interface due to the diverging rf electric field in the distorted sheath. The ion flux was larger on the conductor at the expense of that on the insulator. Both the ion impact angle and angular spread increased progressively as the material interface was approached. The ion impact energy and energy spread were smaller on the insulator as compared to the conductor. For given plasma parameters, as the insulator thickness was increased, the sheath potential and thickness over the insulator decreased, and sheath distortion became more pronounced

  5. Transport Experiments on Topological Insulators

    Science.gov (United States)

    2016-08-16

    anomalous Hall effect was observed when the lowest Landau level is occupied. This system is an especially attractive platform for exploring Weyl physics in...neutral pions decay 300 million times faster than charged pions). In the ensuing 4 decades, the chiral anomaly has come to assume a central, if still...provides an especially attractive system for producing Weyl states. However, the abrupt saturation of ¿yx related to \\Omega, is not predicted by

  6. A Facile Approach to Evaluate Thermal Insulation Performance of Paper Cups

    Directory of Open Access Journals (Sweden)

    Yudi Kuang

    2015-01-01

    Full Text Available Paper cups are ubiquitous in daily life for serving water, soup, coffee, tea, and milk due to their convenience, biodegradability, recyclability, and sustainability. The thermal insulation performance of paper cups is of significance because they are used to supply hot food or drinks. Using an effective thermal conductivity to accurately evaluate the thermal insulation performance of paper cups is complex due to the inclusion of complicated components and a multilayer structure. Moreover, an effective thermal conductivity is unsuitable for evaluating thermal insulation performance of paper cups in the case of fluctuating temperature. In this work, we propose a facile approach to precisely analyze the thermal insulation performance of paper cups in a particular range of temperature by using an evaluation model based on the MISO (Multiple-Input Single-Output technical theory, which includes a characterization parameter (temperature factor and a measurement apparatus. A series of experiments was conducted according to this evaluation model, and the results show that this evaluation model enables accurate characterization of the thermal insulation performance of paper cups and provides an efficient theoretical basis for selecting paper materials for paper cups.

  7. Valence band variation in Si (110) nanowire induced by a covered insulator

    International Nuclear Information System (INIS)

    Hong-Hua, Xu; Xiao-Yan, Liu; Yu-Hui, He; Gang, Du; Ru-Qi, Han; Jin-Feng, Kang; Chun, Fan; Ai-Dong, Sun

    2010-01-01

    In this work, we investigate strain effects induced by the deposition of gate dielectrics on the valence band structures in Si (110) nanowire via the simulation of strain distribution and the calculation of a generalized 6×6k·p strained valence band. The nanowire is surrounded by the gate dielectric. Our simulation indicates that the strain of the amorphous SiO 2 insulator is negligible without considering temperature factors. On the other hand, the thermal residual strain in a nanowire with amorphous SiO 2 insulator which has negligible lattice misfit strain pushes the valence subbands upwards by chemical vapour deposition and downwards by thermal oxidation treatment. In contrast with the strain of the amorphous SiO 2 insulator, the strain of the HfO 2 gate insulator in Si (110) nanowire pushes the valence subbands upwards remarkably. The thermal residual strain by HfO 2 insulator contributes to the up-shifting tendency. Our simulation results for valence band shifting and warping in Si nanowires can provide useful guidance for further nanowire device design. (classical areas of phenomenology)

  8. Improving the Performance of a Semitransparent BIPV by Using High-Reflectivity Heat Insulation Film

    Directory of Open Access Journals (Sweden)

    Huei-Mei Liu

    2016-01-01

    Full Text Available Currently, standard semitransparent photovoltaic (PV modules can largely replace architectural glass installed in the windows, skylights, and facade of a building. Their main features are power generation and transparency, as well as possessing a heat insulating effect. Through heat insulation solar glass (HISG encapsulation technology, this study improved the structure of a typical semitransparent PV module and explored the use of three types of high-reflectivity heat insulation films to form the HISG building-integrated photovoltaics (BIPV systems. Subsequently, the authors analyzed the influence of HISG structures on the optical, thermal, and power generation performance of the original semitransparent PV module and the degree to which enhanced performance is possible. The experimental results indicated that the heat insulation performance and power generation of HISGs were both improved. Selecting an appropriate heat insulation film so that a larger amount of reflective solar radiation is absorbed by the back side of the HISG can yield greater enhancement of power generation. The numerical results conducted in this study also indicated that HISG BIPV system not only provides the passive energy needed for power loading in a building, but also decreases the energy consumption of the HVAC system in subtropical and temperate regions.

  9. Insulation effect on thermal stability of Coated Conductors wires in liquid nitrogen

    Science.gov (United States)

    Rubeli, Thomas; Dutoit, Bertrand; Martynova, Irina; Makarevich, Artem; Molodyk, Alexander; Samoilenkov, Sergey

    2017-02-01

    Superconducting wires are not perfectly homogeneous in term of critical current as well as stabilization. In resistive fault current limiter applications this could lead to hot spots if the fault current is only slightly above the nominal current of the device. Increasing stabilization by using thicker silver coating for example may prevent this problem but this method implies longer wire length to maintain the same impedance during a fault. Very efficient cooling in another way to prevent hot spots, this can be achieved in nucleate boiling regime. Optimal insulation can be used to prevent film boiling regime, staying in nucleate boiling regime in a much broader temperature range. In this work a novel technique is used to monitor in real time the temperature of the wire during the quench. Using this method several increasing insulation thicknesses are tested, measuring for each the heat exchange rate to the nitrogen bath. Exchange rate measurements are made in quasistatic regime and during the re-cooling of the wire. SuperOx wires provided with different insulation thicknesses exhibit an excellent stability, far above a bare wire. On the other side, for very thick insulations the stability gain is lost. Re-cooling speeds dependency on insulation thicknesses is measured too.

  10. Design of Chern insulating phases in honeycomb lattices

    Science.gov (United States)

    Pickett, Warren E.; Lee, Kwan-Woo; Pentcheva, Rossitza

    2018-06-01

    The search for robust examples of the magnetic version of topological insulators, referred to as quantum anomalous Hall insulators or simply Chern insulators, so far lacks success. Our groups have explored two distinct possibilities based on multiorbital 3d oxide honeycomb lattices. Each has a Chern insulating phase near the ground state, but materials parameters were not appropriate to produce a viable Chern insulator. Further exploration of one of these classes, by substituting open shell 3d with 4d and 5d counterparts, has led to realistic prediction of Chern insulating ground states. Here we recount the design process, discussing the many energy scales that are active in participating (or resisting) the desired Chern insulator phase.

  11. Economical evaluation of damaged vacuum insulation panels in buildings

    Science.gov (United States)

    Kim, Y. M.; Lee, H. Y.; Choi, G. S.; Kang, J. S.

    2015-12-01

    In Korea, thermal insulation standard of buildings have been tightened annually to satisfy the passive house standard from the year 2009. The current domestic policies about disseminating green buildings are progressively conducted. All buildings should be the zero energy building in the year 2025, obligatorily. The method is applied to one of the key technologies for high-performance insulation for zero energy building. The vacuum insulation panel is an excellent high performance insulation. But thermal performance of damaged vacuum insulation panels is reduced significantly. In this paper, the thermal performance of damaged vacuum insulation panels was compared and analyzed. The measurement result of thermal performance depends on the core material type. The insulation of building envelope is usually selected by economic feasibility. To evaluate the economic feasibility of VIPs, the operation cost was analyzed by simulation according to the types and damaged ratio of VIPs

  12. Thermal Performance of Cryogenic Multilayer Insulation at Various Layer Spacings

    Science.gov (United States)

    Johnson, Wesley Louis

    2010-01-01

    Multilayer insulation (MLI) has been shown to be the best performing cryogenic insulation system at high vacuum (less that 10 (exp 3) torr), and is widely used on spaceflight vehicles. Over the past 50 years, many investigations into MLI have yielded a general understanding of the many variables that are associated with MLI. MLI has been shown to be a function of variables such as warm boundary temperature, the number of reflector layers, and the spacer material in between reflectors, the interstitial gas pressure and the interstitial gas. Since the conduction between reflectors increases with the thickness of the spacer material, yet the radiation heat transfer is inversely proportional to the number of layers, it stands to reason that the thermal performance of MLI is a function of the number of layers per thickness, or layer density. Empirical equations that were derived based on some of the early tests showed that the conduction term was proportional to the layer density to a power. This power depended on the material combination and was determined by empirical test data. Many authors have graphically shown such optimal layer density, but none have provided any data at such low densities, or any method of determining this density. Keller, Cunnington, and Glassford showed MLI thermal performance as a function of layer density of high layer densities, but they didn't show a minimal layer density or any data below the supposed optimal layer density. However, it was recently discovered that by manipulating the derived empirical equations and taking a derivative with respect to layer density yields a solution for on optimal layer density. Various manufacturers have begun manufacturing MLI at densities below the optimal density. They began this based on the theory that increasing the distance between layers lowered the conductive heat transfer and they had no limitations on volume. By modifying the circumference of these blankets, the layer density can easily be

  13. Non-destructive qualification tests for ITER cryogenic axial insulating breaks

    International Nuclear Information System (INIS)

    Kosek, Jacek; Lopez, Roberto; Tommasini, Davide; Rodriguez-Mateos, Felix

    2014-01-01

    In the ITER superconducting magnets the dielectric separation between the CICC (Cable-In-Conduit Conductors) and the helium supply pipes is made through the so-called insulating breaks (IB). These devices shall provide the required dielectric insulation at a 30 kV level under different types of stresses and constraints: thermal, mechanical, dielectric and ionizing radiations. As part of the R and D program, the ITER Organization launched contracts with industrial companies aimed at the qualification of the manufacturing techniques. After reviewing the main functional aspects, this paper describes and discusses the protocol established for non-destructive qualification tests of the prototypes

  14. Observation of zone folding induced acoustic topological insulators and the role of spin-mixing defects

    Science.gov (United States)

    Deng, Yuanchen; Ge, Hao; Tian, Yuan; Lu, Minghui; Jing, Yun

    2017-11-01

    This article reports on the experimental realization of a flow-free, pseudospin-based acoustic topological insulator designed using the strategy of zone folding. Robust sound one-way propagation is demonstrated with the presence of non-spin-mixing defects. On the other hand, it is shown that spin-mixing defects, which break the geometric symmetry and therefore the pseudo-time-reversal symmetry, can open up nontrivial band gaps within the edge state frequency band, and their width can be tailored by the extent of the defect. This provides a possible route for realizing tunable acoustic topological insulators.

  15. Specific features of the photoconductivity of semi-insulating cadmium telluride

    Energy Technology Data Exchange (ETDEWEB)

    Golubyatnikov, V. A.; Grigor’ev, F. I.; Lysenko, A. P., E-mail: aplysenko@hse.ru; Strogankova, N. I.; Shadov, M. B. [National Research University Higher School of Economics, Moscow Institute of Electronics and Mathematics (Russian Federation); Belov, A. G. [OAO GIREDMET State Research and Design Institute of the Rare-Metal Industry (Russian Federation)

    2014-12-15

    The effect of local illumination providing a high level of free-carrier injection on the conductivity of a sample of semi-insulating cadmium telluride and on the properties of ohmic contacts to the sample is studied. It is found that, irrespective of the illumination region, the contact resistance of ohmic contacts decreases and the concentration of majority carriers in the sample grows in proportion to the illumination intensity. It is shown that inherent heterogeneities in crystals of semi-insulating semiconductors can be studied by scanning with a light probe.

  16. The ESKSISO diagnostic system intended for assessment of insulating system of the oil-filled equipment

    Directory of Open Access Journals (Sweden)

    Chernyshev V. A.

    2015-12-01

    Full Text Available The expert system (ES intended for assessment of condition of the insulating system of oil-filled transformers has been presented. ES is based on the analysis of the processes of polarization and depolarization proceeding in volume of insulating intervals of the power equipment; it allows to create effectively the conclusion about a condition of controlled object as parameters of control act not so much as characteristics of materials but as characteristics of processes of dielectric designs' aging. A distinctive feature of expert system is the possibility to obtain necessary information about operation parameters defining reliability and duration of work and providing high efficiency of power equipment service

  17. Energy Renovations: Volume 17: Insulation - A Guide for Contractors to Share with Homeowners

    Energy Technology Data Exchange (ETDEWEB)

    Baechler, Michael C.; Adams, Karen; Hefty, Marye G.; Gilbride, Theresa L.; Love, Pat M.

    2012-05-15

    This report was prepared by PNNL for DOE's Building America program and is intended as a guide that energy performance contractors can share with homeowners to describe various insulation options for improving the energy performance and comfort of existing homes. The report provides descriptions of many common insulation types, including their advantages and disadvantages, R-values, characteristics, and typical uses. The report also describes potentially hazardous products such as asbestos and formaldehyde and safety issues when conducting energy-efficient upgrades including radon. The guide is available for download at the DOE Building America website, www.buildingamerica.gov.

  18. Non-destructive qualification tests for ITER cryogenic axial insulating breaks

    Energy Technology Data Exchange (ETDEWEB)

    Kosek, Jacek [Wroclaw University of Technology, Wybrzeze Wyspianskiego 27, 50-370 Wroclaw, Poland and CERN, Geneva 23,CH-1211 (Switzerland); Lopez, Roberto; Tommasini, Davide [CERN, Geneva 23,CH-1211 (Switzerland); Rodriguez-Mateos, Felix [CERN, Geneva 23,CH-1211, Switzerland and ITER Organization, Route de Vinon sur Verdon, 13115 Saint Paul lez Durance (France)

    2014-01-29

    In the ITER superconducting magnets the dielectric separation between the CICC (Cable-In-Conduit Conductors) and the helium supply pipes is made through the so-called insulating breaks (IB). These devices shall provide the required dielectric insulation at a 30 kV level under different types of stresses and constraints: thermal, mechanical, dielectric and ionizing radiations. As part of the R and D program, the ITER Organization launched contracts with industrial companies aimed at the qualification of the manufacturing techniques. After reviewing the main functional aspects, this paper describes and discusses the protocol established for non-destructive qualification tests of the prototypes.

  19. Optically Transparent Thermally Insulating Silica Aerogels for Solar Thermal Insulation.

    Science.gov (United States)

    Günay, A Alperen; Kim, Hannah; Nagarajan, Naveen; Lopez, Mateusz; Kantharaj, Rajath; Alsaati, Albraa; Marconnet, Amy; Lenert, Andrej; Miljkovic, Nenad

    2018-04-18

    Rooftop solar thermal collectors have the potential to meet residential heating demands if deployed efficiently at low solar irradiance (i.e., 1 sun). The efficiency of solar thermal collectors depends on their ability to absorb incoming solar energy and minimize thermal losses. Most techniques utilize a vacuum gap between the solar absorber and the surroundings to eliminate conduction and convection losses, in combination with surface coatings to minimize reradiation losses. Here, we present an alternative approach that operates at atmospheric pressure with simple, black, absorbing surfaces. Silica based aerogels coated on black surfaces have the potential to act as simple and inexpensive solar thermal collectors because of their high transmission to solar radiation and low transmission to thermal radiation. To demonstrate their heat-trapping properties, we fabricated tetramethyl orthosilicate-based silica aerogels. A hydrophilic aerogel with a thickness of 1 cm exhibited a solar-averaged transmission of 76% and thermally averaged transmission of ≈1% (at 100 °C). To minimize unwanted solar absorption by O-H groups, we functionalized the aerogel to be hydrophobic, resulting in a solar-averaged transmission of 88%. To provide a deeper understanding of the link between aerogel properties and overall efficiency, we developed a coupled radiative-conductive heat transfer model and used it to predict solar thermal performance. Instantaneous solar thermal efficiencies approaching 55% at 1 sun and 80 °C were predicted. This study sheds light on the applicability of silica aerogels on black coatings for solar thermal collectors and offers design priorities for next-generation solar thermal aerogels.

  20. 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.

  1. Experiences with sound insulating open windows in traffic noise exposed housing

    DEFF Research Database (Denmark)

    Rasmussen, Birgit

    2015-01-01

    windows are open, not least to reduce sleep disturbance. Unfortunately, such window solutions are complicated and expensive and practical experience limited. Nevertheless, they have been included in some Danish projects. To support further development and use, experience from seven field cases......Sound insulating windows are widely used in traffic noise exposed residential areas to reduce indoor noise levels to acceptable levels. However, such windows are typically only designed to provide sound insulation in closed position, and many people prefer open windows parts of time for ventilation...... purposes, including during night, or simply because it’s a good feeling to have windows open to be in contact with the surroundings. High noise exposure can lead to adverse effects on comfort and health, and thus, there is a need for sound insulating open windows to reduce noise exposure in homes, when...

  2. Charge disproportionation in RNiO3 at the metal-insulator transition

    International Nuclear Information System (INIS)

    Alonso, J.A.; Martinez-Lope, M.J.; Casais, M.T.; Garcia-Munoz, J.L.; Fernandez-Diaz, M.T.; Aranda, M.A.G.

    1999-01-01

    Complete text of publication follows. Neutron and synchrotron diffraction data provide the first observation of changes in the crystal symmetry at the metal-insulator (MI) transition in RNiO 3 perovskites [1]. At high temperatures, YNiO 3 is orthorhombic and metallic but below T MI = 582 K it changes to a monoclinic insulator. The monoclinic symmetry is due to a partial 2 Ni 3+ → Ni 3+δ + Ni 3-δ charge disproportionation associated to the MI transition. In the insulating state the presence of two NiO 6 octahedra is reported with, respectively, expanded (Ni1) and contracted (Ni2) Ni-O bonds, that alternated along the three directions of the crystal. Corroborating the charge disproportion, unequal moments are found at Ni1 and Ni2 octahedra in the low temperature monoclinic phase. (author) J.A. Alonso et al, Phys. Rev. Lett. in press

  3. Aerogel-Based Multilayer Insulation with Micrometeoroid Protection

    Science.gov (United States)

    Begag, Redouane; White, Shannon

    2013-01-01

    Ultra-low-density, highly hydrophobic, fiber-reinforced aerogel material integrated with MLI (aluminized Mylar reflectors and B4A Dacron separators) offers a highly effective insulation package by providing unsurpassed thermal performance and significant robustness, delivering substantial MMOD protection via the addition of a novel, durable, external aerogel layer. The hydrophobic nature of the aerogel is an important property for maintaining thermal performance if the material is exposed to the environment (i.e. rain, snow, etc.) during ground installations. The hybrid aerogel/MLI/MMOD solution affords an attractive alternative because it will perform thermally in the same range as MLI at all vacuum levels (including high vacuum), and offers significant protection from micrometeoroid damage. During this effort, the required low-density and resilient aerogel materials have been developed that are needed to optimize the thermal performance for space (high vacuum) cryotank applications. The proposed insulation/MMOD package is composed of two sections: a stack of interleaved aerogel layers and MLI intended for cryotank thermal insulation, and a 1.5- to 1-in. (.2.5- to 3.8- cm) thick aerogel layer (on top of the insulation portion) for MMOD protection. Learning that low-density aerogel cannot withstand the hypervelocity impact test conditions, the innovators decided during the course of the program to fabricate a high-density and strong material based on a cross-linked aerogel (X-aerogel; developed elsewhere by the innovators) for MMOD protection. This system has shown a very high compressive strength that is capable of withstanding high-impact tests if a proper configuration of the MMOD aerogel layer is used. It was learned that by stacking two X-aerogel layers [1.5-in. (.3.8-cm) thick] separated by an air gap, the system would be able to hold the threat at a speed of 5 km/s and gpass h the test. The first aerogel panel stopped the projectile from damaging the second

  4. Thermally-insulating layer for nuclear reactors

    International Nuclear Information System (INIS)

    1975-01-01

    The thermally-insulating layer has been designed both for insulating surfaces within the core of a nuclear reactor and transmitting loads such as the core-weight. Said layer comprises a layer of bricks and a layer of tiles with smaller clearance between the tiles than between the bricks, the latter having a reduced cross-section against the tiles so as to be surrounded by relatively large interconnected ducts forming a continuous chamber behind the tile-layer in order to induce a substantial decreases in the transverse flow of the reactor-core coolant. The core preferably comprises hexagonal columns supported by rhomb-shaped plates, with channels distributed so as to mix the coolant of twelve columns. The plates are separated from support-tiles by means of pillars [fr

  5. Self-magnetically insulated ion diode

    International Nuclear Information System (INIS)

    VanDevender, J.; Quintenz, J.; Leeper, R.; Johnson, D.; Crow, J.

    1981-01-01

    Light ion diodes for producing 1--100 TW ion beams are required for inertial confinement fusion. The theory, numerical simulations, and experiments on a self-magnetically insulated ion diode are presented. The treatment is from the point of view of a self-magnetically insulated transmission line with an ion loss current and differs from the usual treatment of the pinched electron beam diode. The simulations show that the ratio V/IZ 0 =0.25 in such a structure with voltage V, local total current I, and local vacuum wave impedance Z 0 . The ion current density is enhanced by a factor of approximately 2 over the simple space-charge limited value. The simulation results are verified in an experiment. An analytical theory is then presented for scaling the results to produce a focused beam of protons with a power of up to 10 13 W

  6. Individual Magnetic Molecules on Ultrathin Insulating Surfaces

    Science.gov (United States)

    El Hallak, Fadi; Warner, Ben; Hirjibehedin, Cyrus

    2012-02-01

    Single molecule magnets have attracted ample interest because of their exciting magnetic and quantum properties. Recent studies have demonstrated that some of these molecules can be evaporated on surfaces without losing their magnetic properties [M. Mannini et al., Nature 468, 417, (2010)]. This remarkable progress enhances the chances of real world applications for these molecules. We present STM imaging and spectroscopy data on iron phthalocyanine molecules deposited on Cu(100) and on a Cu2N ultrathin insulating surface. These molecules have been shown to display a large magnetic anisotropy on another thin insulating surface, oxidized Cu(110) [N. Tsukahara et al., Phys. Rev. Lett. 102, 167203 (2009)]. By using a combination of elastic and inelastic electron tunnelling spectroscopy, we investigate the binding of the molecules to the surface and the impact that the surface has on their electronic and magnetic properties.

  7. Tests on irradiated magnet-insulator materials

    International Nuclear Information System (INIS)

    Schmunk, R.E.; Miller, L.G.; Becker, H.

    1983-01-01

    Fusion-reactor coils, located in areas where they will be only partially shielded, must be fabricated from materials which are as resistant to radiation as possible. They will probably incorporate resistive conductors with either water or cryogenic cooling. Inorganic insulators have been recommended for these situations, but the possibility exists that some organic insulators may be usuable as well. Results were previously reported for irradiation and testing of three glass reinforced epoxies: G-7, G-10, and G-11. Thin disks of these materials, nominally 0.5 mm thick by 11.1 mm diameter, were tested in compressive fatigue, a configuration and loading which represents reasonably well the magnet environment. In that work G-10 was shown to withstand repeated loading to moderately high stress levels without failure, and the material survived better at liquid nitrogen temperature than at room temperature

  8. Development of radiation resistant PEEK insulation cable

    International Nuclear Information System (INIS)

    Mio, Keigo; Ogiwara, Norio; Hikichi, Yusuke; Furukori, Hisayoshi; Arai, Hideyuki; Nishizawa, Daiji; Nishidono, Toshiro

    2009-04-01

    Material characterization and development has been carried out for cable insulation suitable for use in the J-PARC 3-GeV RCS radiation environment. In spite of its high cost, PEEK (polyether-ether-ketone) has emerged as the leading candidate satisfying requirements of being non-halogen based, highly incombustible and with radiation resistant at least 10 MGy, along with the usual mechanical characteristics such as good elongation at break, which are needed in a cable insulation. Gamma-ray irradiation tests have been done in order to study radiation resistance of PEEK cable. Further, mechanical, electrical and fire retardant characteristics of a complete cable such as would be used at the J-PARC RCS were investigated. As a result, PEEK cables were shown to be not degraded by radiation up to at least 10 MGy, and thus could be expected to operate stably under the 3-GeV RCS radiation environment. (author)

  9. Correlations in hydrothermal properties of building insulation

    International Nuclear Information System (INIS)

    Antonyová, A

    2013-01-01

    The contribution comprises analysis that is based on scientific work as a part of participation on the international research project carried out at the University of Prešov in Prešov and Vienna University of Technology entitled 'Detection and Management of Risk Processes in Building Insulation' and numbered SRDA SK-AT-0008-10. Statistical approach with correlations among humidity, time and temperature values in the space between the wall and building insulation uses the set of data obtained during the measurement series as testing using a new technology with equipment that does not influence the environment properties in the space. Therefore such real mapping can bring a real picture of possible condensation as a risk process in the building envelope.

  10. Edge forward mechanical protection for porcelain insulators

    Energy Technology Data Exchange (ETDEWEB)

    deCasseres, D.K.

    1987-12-01

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

  11. Excavationless Exterior Foundation Insulation Exploratory Study

    Energy Technology Data Exchange (ETDEWEB)

    Mosiman, G.; Wagner, R.; Schirber, T.

    2013-02-01

    The key objective of this exploratory study was to investigate the feasibility of the development or adoption of technologies that would enable a large percentage of existing homes in cold climates to apply a combination 'excavationless' soil removal process with appropriate insulation and water management on the exterior of existing foundations at a low cost. Our approach was to explore existing excavation and material technologies and systems to discover whether potential successful combinations existed.

  12. Organic insulator studies at Los Alamos

    International Nuclear Information System (INIS)

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

    1981-01-01

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

  13. D.B.S. in disordered insulators

    International Nuclear Information System (INIS)

    Bunch, J.M.

    1976-01-01

    These studies were undertaken in order to determine insulator properties for the CTR program. Most of the d.b.s. studies so far have been with various forms of Al 2 O 3 . Some work using fission neutrons and 15-MeV protons along with some high-energy heavy ions is briefly described. Attempts to measure d.b.s. and other electrical properties are mentioned

  14. Electronic correlations in insulators, metals and superconductors

    Energy Technology Data Exchange (ETDEWEB)

    Sentef, Michael Andreas

    2010-12-03

    In this thesis dynamical mean-field methods in combination with a continuous-time quantum Monte Carlo impurity solver are used to study selected open problems of condensed matter theory. These problems comprise the effect of correlations and their quantification in covalent band insulators, non-local correlation effects and their intriguing consequences in frustrated two-dimensional systems, and a phenomenological approach to investigate temperature-dependent transport in graphene in the presence of disorder. (orig.)

  15. Spectral correlations in Anderson insulating wires

    Science.gov (United States)

    Marinho, M.; Micklitz, T.

    2018-01-01

    We calculate the spectral level-level correlation function of Anderson insulating wires for all three Wigner-Dyson classes. A measurement of its Fourier transform, the spectral form factor, is within reach of state-of-the-art cold atom quantum quench experiments, and we find good agreement with recent numerical simulations of the latter. Our derivation builds on a representation of the level-level correlation function in terms of a local generating function which may prove useful in other contexts.

  16. 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.

  17. NDE of ceramic insulator blanks by radiography

    International Nuclear Information System (INIS)

    Sarvanan, S.; Venkatraman, B.; Jayakumar, T.; Baldev Raj

    1996-01-01

    The production of ceramic insulators in electrical industry involves a number of steps, one of which is the green blank. The defects such as voids and crack can be present in the extruded green blank. One of the best non-destructive evaluation (NDE) technique radiography. This paper deals with the development of methodology based on theoretical modeling for the examination of ceramics by high sensitivity radiography. (author)

  18. Thermic insulation in the United States

    Energy Technology Data Exchange (ETDEWEB)

    Nicolaon, G. (Ambassade de France a New York (USA)); Atlas, O. (Illinois Institute of Technology, Chicago, (USA))

    1984-01-30

    At present, thermic insulation accounts for 13% of the savings which have been made and this percentage should increase substantially in the future. The ideal insulation material must have low thermic conductivity, but also be light, have a low dilatation coefficient, good mechanical resistance and be fireproof and non-toxic. Rock wool and above all glass wool have the major portion in the insulation market with about 75% of the total. The prospects for an increase in sales are average: 6 to 7% per year until 1990 with a stabilization or a decrease after this date. Production is concentrated in the hands of about ten producers. The insulation with a cellulose base -with the addition of a combustion inhibitor, usually borax- represent about 15% of the market. Manufacturers are numerous and the production units are small. Any serious evaluation of the future of this product is difficult to make. However, it should be noted that combustion inhibition is one of the main factors of success of this product and constitutes a relatively active field of research. Perlite and vermiculite have a marginal part of the market which is concentrated in the hands of a few dozen producers. Their future seems promising and their production should double between now and the end of the century. There is also the field of plastics which has to be considered and notably polystyrene, polyurethanes and polyisocyanates. These can be injected and moulded in situ. To the extent that toxicity studies can definitively conclude that they are not harmful (urea-formol resins have just been prohibited), their future is brillant and their growth rate could reach about 200% per year. The big chemical and pharmaceutical companies are interested in these products and their portion of the market can rapidly go beyond their present 6 to 8%.

  19. Metal-insulator transition in vanadium dioxide

    International Nuclear Information System (INIS)

    Zylbersztejn, A.; Mott, N.F.

    1975-01-01

    The basic physical parameters which govern the metal-insulator transition in vanadium dioxide are determined through a review of the properties of this material. The major importance of the Hubbard intra-atomic correlation energy in determining the insulating phase, which was already evidence by studies of the magnetic properties of V 1 -/subx/Cr/subx/O 2 alloys, is further demonstrated from an analysis of their electrical properties. An analysis of the magnetic susceptibility of niobium-doped VO 2 yields a picture for the current carrier in the low-temperature phase in which it is accompanied by a spin cloud (owing to Hund's-rule coupling), and has therefore an enhanced mass (m approx. = 60m 0 ). Semiconducting vanadium dioxide turns out to be a borderline case for a classical band-transport description; in the alloys at high doping levels, Anderson localization with hopping transport can take place. Whereas it is shown that the insulating phase cannot be described correctly without taking into account the Hubbard correlation energy, we find that the properties of the metallic phase are mainly determined by the band structure. Metallic VO 2 is, in our view, similar to transition metals like Pt or Pd: electrons in a comparatively wide band screening out the interaction between the electrons in a narrow overlapping band. The magnetic susceptibility is described as exchange enhanced. The large density of states at the Fermi level yields a substantial contribution of the entropy of the metallic electrons to the latent heat. The crystalline distortion removes the band degeneracy so that the correlation energy becomes comparable with the band width and a metal-insulator transition takes place

  20. Phase Separation in Doped Mott Insulators

    Directory of Open Access Journals (Sweden)

    Chuck-Hou Yee

    2015-04-01

    Full Text Available Motivated by the commonplace observation of Mott insulators away from integer filling, we construct a simple thermodynamic argument for phase separation in first-order doping-driven Mott transitions. We show how to compute the critical dopings required to drive the Mott transition using electronic structure calculations for the titanate family of perovskites, finding good agreement with experiment. The theory predicts that the transition is percolative and should exhibit Coulomb frustration.

  1. Coherence and correlations in a Mott insulator

    International Nuclear Information System (INIS)

    Gerbier, F.; Widera, A.; Foelling, S.; Mandel, O.; Gericke, T.; Bloch, I.

    2005-01-01

    The observation of the super fluid to Mott insulator transition has triggered an intense interest in studying ultracold quantum gases in optical lattices. Such a transition is commonly associated with the disappearance of the interference pattern observed when releasing a coherent (i.e. Bose condensed) ensemble from the lattice. In this talk, I will show that even in the insulating phase, the visibility of this interference pattern remains finite. Our results show that although long-range order is absent, short-range coherence still persists in a rather broad range, and that this can be identified as a characteristic feature of the system for large, but finite lattice depths. For even deeper lattices, the visibility is close to zero, and the interference pattern unobservable. I will explain that information is still present in such featureless images, and can be extracted by studying the density-density correlation function of the expanded cloud, as proposed theoretically. A sharp diffraction-like pattern observed in the correlations reveals the underlying lattice structure, and can be understood by generalizing the well-known Hanbury-Brown and Twiss effect to many bosonic sources '' emitting '' from each lattice site. This new detection method allows in principle the detection of spin ordering in a multi-component Mott insulator. As a first step in this direction, we have recently observed spin dynamics in a Mott insulator, where a spin-dependent collisional coupling induces strongly under damped Rabi oscillations between two-particle states with the same total magnetization. I will briefly report on these results. (author)

  2. Fabricate-On-Demand Vacuum Insulating Glazings

    Energy Technology Data Exchange (ETDEWEB)

    McCamy, James W. [PPG Industries, Inc., Pittsburgh, PA (United States)

    2017-09-19

    PPG proposed to design a fabricate-on-demand manufacturing process to overcome the cost and supply chain issues preventing widespread adoption of vacuum insulated glazing (VIG) units. To do so, we focused on improving three areas of VIG manufacturing that drive high costs and limit the ability for smaller manufacturers to enter the market: edge sealing, pillar design/placement, and evacuating the VIG.

  3. Electronic correlations in insulators, metals and superconductors

    International Nuclear Information System (INIS)

    Sentef, Michael Andreas

    2010-01-01

    In this thesis dynamical mean-field methods in combination with a continuous-time quantum Monte Carlo impurity solver are used to study selected open problems of condensed matter theory. These problems comprise the effect of correlations and their quantification in covalent band insulators, non-local correlation effects and their intriguing consequences in frustrated two-dimensional systems, and a phenomenological approach to investigate temperature-dependent transport in graphene in the presence of disorder. (orig.)

  4. Plasma immersion ion implantation into insulating materials

    International Nuclear Information System (INIS)

    Tian Xiubo; Yang Shiqin

    2006-01-01

    Plasma immersion ion implantation (PIII) is an effective surface modification tool. During PIII processes, the objects to be treated are immersed in plasmas and then biased to negative potential. Consequently the plasma sheath forms and ion implantation may be performed. The pre-requirement of plasma implantation is that the object is conductive. So it seems difficult to treat the insulating materials. The paper focuses on the possibilities of plasma implantation into insulting materials and presents some examples. (authors)

  5. Fabrication of insulator nanocapillaries from diatoms

    International Nuclear Information System (INIS)

    Bereczky, R.J.; Tokesi, K.

    2006-01-01

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

  6. Humidity effects on wire insulation breakdown strength.

    Energy Technology Data Exchange (ETDEWEB)

    Appelhans, Leah

    2013-08-01

    Methods for the testing of the dielectric breakdown strength of insulation on metal wires under variable humidity conditions were developed. Two methods, an ASTM method and the twisted pair method, were compared to determine if the twisted pair method could be used for determination of breakdown strength under variable humidity conditions. It was concluded that, although there were small differences in outcomes between the two testing methods, the non-standard method (twisted pair) would be appropriate to use for further testing of the effects of humidity on breakdown performance. The dielectric breakdown strength of 34G copper wire insulated with double layer Poly-Thermaleze/Polyamide-imide insulation was measured using the twisted pair method under a variety of relative humidity (RH) conditions and exposure times. Humidity at 50% RH and below was not found to affect the dielectric breakdown strength. At 80% RH the dielectric breakdown strength was significantly diminished. No effect for exposure time up to 140 hours was observed at 50 or 80%RH.

  7. Nonlinear Optical Functions in Crystalline and Amorphous Silicon-on-Insulator Nanowires

    DEFF Research Database (Denmark)

    Baets, R.; Kuyken, B.; Liu, X.

    2012-01-01

    Silicon-on-Insulator nanowires provide an excellent platform for nonlinear optical functions in spite of the two-photon absorption at telecom wavelengths. Work on both crystalline and amorphous silicon nanowires is reviewed, in the wavelength range of 1.5 to 2.5 µm....

  8. 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.

  9. 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.

  10. Allowance for insulation aging in the new concept of accelerated life tests of high-voltage power transformers

    International Nuclear Information System (INIS)

    Levit, A.G.; Grechko, O.N.; Shchipunova, N.P.

    1992-01-01

    This paper reports that the existing system of type and acceptance tests of high-voltage transformer insulation does not take into account insulation ageing, which is particularly objectionable with respect to equip-met with reduced insulation levels. Suggested in the paper is a new concept of accelerated life tests based on integrated simulation of basic operating loads, both periodic (surge) and long-term ones; by making a long-term accelerated test simulating the working conditions, with exposure of test object and/or its insulation to periodic operating surges (overvoltages and overcurrents). This test replaces a group of conventional individual acceptance tests and provides more ample and more precise information on performance and dependability of the equipment. The test procedure was checked in test of a small lot of 1600 kVA 35 kV power transformers

  11. Thermal Insulating Concrete Wall Panel Design for Sustainable Built Environment

    Science.gov (United States)

    Zhou, Ao; Wong, Kwun-Wah

    2014-01-01

    Air-conditioning system plays a significant role in providing users a thermally comfortable indoor environment, which is a necessity in modern buildings. In order to save the vast energy consumed by air-conditioning system, the building envelopes in envelope-load dominated buildings should be well designed such that the unwanted heat gain and loss with environment can be minimized. In this paper, a new design of concrete wall panel that enhances thermal insulation of buildings by adding a gypsum layer inside concrete is presented. Experiments have been conducted for monitoring the temperature variation in both proposed sandwich wall panel and conventional concrete wall panel under a heat radiation source. For further understanding the thermal effect of such sandwich wall panel design from building scale, two three-story building models adopting different wall panel designs are constructed for evaluating the temperature distribution of entire buildings using finite element method. Both the experimental and simulation results have shown that the gypsum layer improves the thermal insulation performance by retarding the heat transfer across the building envelopes. PMID:25177718

  12. Spatially-protected Topology and Group Cohomology in Band Insulators

    Science.gov (United States)

    Alexandradinata, A.

    This thesis investigates band topologies which rely fundamentally on spatial symmetries. A basic geometric property that distinguishes spatial symmetry regards their transformation of the spatial origin. Point groups consist of spatial transformations that preserve the spatial origin, while un-split extensions of the point groups by spatial translations are referred to as nonsymmorphic space groups. The first part of the thesis addresses topological phases with discretely-robust surface properties: we introduce theories for the Cnv point groups, as well as certain nonsymmorphic groups that involve glide reflections. These band insulators admit a powerful characterization through the geometry of quasimomentum space; parallel transport in this space is represented by the Wilson loop. The non-symmorphic topology we study is naturally described by a further extension of the nonsymmorphic space group by quasimomentum translations (the Wilson loop), thus placing real and quasimomentum space on equal footing -- here, we introduce the language of group cohomology into the theory of band insulators. The second part of the thesis addresses topological phases without surface properties -- their only known physical consequences are discrete signatures in parallel transport. We provide two such case studies with spatial-inversion and discrete-rotational symmetries respectively. One lesson learned here regards the choice of parameter loops in which we carry out transport -- the loop must be chosen to exploit the symmetry that protects the topology. While straight loops are popular for their connection with the geometric theory of polarization, we show that bent loops also have utility in topological band theory.

  13. Topological phononic insulator with robust pseudospin-dependent transport

    Science.gov (United States)

    Xia, Bai-Zhan; Liu, Ting-Ting; Huang, Guo-Liang; Dai, Hong-Qing; Jiao, Jun-Rui; Zang, Xian-Guo; Yu, De-Jie; Zheng, Sheng-Jie; Liu, Jian

    2017-09-01

    Topological phononic states, which facilitate unique acoustic transport around defects and disorders, have significantly revolutionized our scientific cognition of acoustic systems. Here, by introducing a zone folding mechanism, we realize the topological phase transition in a double Dirac cone of the rotatable triangular phononic crystal with C3 v symmetry. We then investigate the distinct topological edge states on two types of interfaces of our phononic insulators. The first one is a zigzag interface which simultaneously possesses a symmetric mode and an antisymmetric mode. Hybridization of the two modes leads to a robust pseudospin-dependent one-way propagation. The second one is a linear interface with a symmetric mode or an antisymmetric mode. The type of mode is dependent on the topological phase transition of the phononic insulators. Based on the rotatability of triangular phononic crystals, we consider several complicated contours defined by the topological zigzag interfaces. Along these contours, the acoustic waves can unimpededly transmit without backscattering. Our research develops a route for the exploration of the topological phenomena in experiments and provides an excellent framework for freely steering the acoustic backscattering-immune propagation within topological phononic structures.

  14. Electric breakdown of high polymer insulating materials at cryogenic temperature

    International Nuclear Information System (INIS)

    Kim, Sanhyon; Yoshino, Katsumi

    1985-01-01

    Cryogenic properties : temperature dependence of E sub(b) and effects of media upon E sub(b) were investigated on several high polymers. Temperature conditions were provided by liquid He (4.2 K), liquid N 2 (77 K) and cryogen (dry ice-methyl alcohol, 194 K). Silicone oil was used also at ambient temperature and elevated temperature. Polymer film coated with gold by vacuum evaporation was placed in cryostat, and high tension from pulse generator was applied to the film. Dielectric breakdowns were detected by oscilloscope and observed visually. The results of experiment are summerized as follow. (1) E sub(b) of film in He is affected by medium remarkably, and covering with 3-methyl pentane is effective for increasing E sub(b). (2) Temperature dependence of E sub(b) was not recognized in cryogenic temperature below liquid N 2 . (3) Temperature characteristic of E sub(b) changes considerably at the critical temperature T sub(c), and T sub(c) is dependent on material. (4) Strength against dielectric breakdown under cryogenic temperature is not affected by bridging caused by irradiation of electron beam. (5) Dielectric breakdown is thought to be caused by electronic process such as electron avalanche. Consequently, for designing insulation for the temperature below liquid He, insulation design for liquid N 2 is thought to be sufficient. However, the degradation and breakdown by mechanical stress under cryogenic temperature must be taken into consideration. (Ishimitsu, A.)

  15. Quasiparticle dynamics in reshaped helical Dirac cone of topological insulators.

    Science.gov (United States)

    Miao, Lin; Wang, Z F; Ming, Wenmei; Yao, Meng-Yu; Wang, Meixiao; Yang, Fang; Song, Y R; Zhu, Fengfeng; Fedorov, Alexei V; Sun, Z; Gao, C L; Liu, Canhua; Xue, Qi-Kun; Liu, Chao-Xing; Liu, Feng; Qian, Dong; Jia, Jin-Feng

    2013-02-19

    Topological insulators and graphene present two unique classes of materials, which are characterized by spin-polarized (helical) and nonpolarized Dirac cone band structures, respectively. The importance of many-body interactions that renormalize the linear bands near Dirac point in graphene has been well recognized and attracted much recent attention. However, renormalization of the helical Dirac point has not been observed in topological insulators. Here, we report the experimental observation of the renormalized quasiparticle spectrum with a skewed Dirac cone in a single Bi bilayer grown on Bi(2)Te(3) substrate from angle-resolved photoemission spectroscopy. First-principles band calculations indicate that the quasiparticle spectra are likely associated with the hybridization between the extrinsic substrate-induced Dirac states of Bi bilayer and the intrinsic surface Dirac states of Bi(2)Te(3) film at close energy proximity. Without such hybridization, only single-particle Dirac spectra are observed in a single Bi bilayer grown on Bi(2)Se(3), where the extrinsic Dirac states Bi bilayer and the intrinsic Dirac states of Bi(2)Se(3) are well separated in energy. The possible origins of many-body interactions are discussed. Our findings provide a means to manipulate topological surface states.

  16. Cryogenic Testing of Different Seam Concepts for Multilayer Insulation Systems

    Science.gov (United States)

    Johnson, Wesley L.; Fesmire, J. E.

    2009-01-01

    Recent testing in a cylindrical, comparative cryostat at the Cryogenics Test Laboratory has focused on various seam concepts for multilayer insulation systems. Three main types of seams were investigated: straight overlap, fold-over, and roll wrapped. Each blanket was comprised of 40 layer pairs of reflector and spacer materials. The total thickness was approximately 12.5-mm, giving an average layer density of 32 layers per centimeter. The blankets were tested at high vacuum, soft vacuum, and no vacuum using liquid nitrogen to maintain the cold boundary temperature at 77 K. Test results show that all three seam concepts are all close in thermal performance; however the fold-over method provides the lowest heat flux. For the first series of tests, seams were located 120 degrees around the circumference of the cryostat from the previous seam. This technique appears to have lessened the degradation of the blanket due to the seams. In a follow-on test, a 20 layer blanket was tested in a roll wrapped configuration and then cut down the side of the cylinder, taped together, and re-tested. This test result shows the thermal performance impact of having the seams all in one location versus having the seams clocked around the vessel. This experimental investigation indicates that the method of joining the seams in multilayer insulation systems is not as critical as the quality of the installation process.

  17. The full-scale process and design changes for elimination of insulation edge separations and voids in tang flap area

    Science.gov (United States)

    Danforth, Richard A.

    1991-01-01

    Qualification of the full-scale process and design changes for elimination of redesigned solid rocket motor tang nitrile butadiene rubber insulation edge separations and voids was performed from 24 March to 3 December 1990. The objectives of this test were: to qualify design and process changes on flight hardware using a tie ply between the redesigned solid rocket motor steel case and the nitrile butadiene rubber insulation over the tang capture features; to qualify the use of methyl ethyl ketone in the tang flap region to reduce voids; and to determine if holes in the separator film reduce voids in the tang flap region. The tie ply is intended to aid insulation flow during the insulation cure process, and thus reduce or eliminate edge unbonds. Methyl ethyl ketone is intended to reduce voids in the tang flap area by providing better tacking characteristics. The perforated film was intended to provide possible vertical breathe paths to reduce voids in the tang area. Tang tie ply testing consisted of 270 deg of the tang circumference using a new layup method and 90 deg of the tang circumference using the current layup methods. Tie ply process success was defined as a reduction of insulation unbonds. Lack of any insulation edge unbonds on the tang area where the new process was used, and the presence of 17 unbonds with the current process, proves the test to be a success. Successful completion of this test has qualified the new processes.

  18. Charged particle beam scanning using deformed high gradient insulator

    Science.gov (United States)

    Chen, Yu -Jiuan

    2015-10-06

    Devices and methods are provided to allow rapid deflection of a charged particle beam. The disclosed devices can, for example, be used as part of a hadron therapy system to allow scanning of a target area within a patient's body. The disclosed charged particle beam deflectors include a dielectric wall accelerator (DWA) with a hollow center and a dielectric wall that is substantially parallel to a z-axis that runs through the hollow center. The dielectric wall includes one or more deformed high gradient insulators (HGIs) that are configured to produce an electric field with an component in a direction perpendicular to the z-axis. A control component is also provided to establish the electric field component in the direction perpendicular to the z-axis and to control deflection of a charged particle beam in the direction perpendicular to the z-axis as the charged particle beam travels through the hollow center of the DWA.

  19. Thermal insulation product for insulation, especially in nuclear power engineering, and method of its production

    International Nuclear Information System (INIS)

    Veselovsky, P.; Zink, S.; Balacek, P.; Mares, I.

    1989-01-01

    The insulation consists of a sewn fabric cover made of inorganic fibers, in which the fiber filling is reinforced mechanically by dense point interweaving. The inorganic fibers, 1 to 5 μm in diameter, consist of min. 97 wt.% mixture of aluminium and silicon oxides in the vitreous state. The fibers making up the cover consist of min. 95% silicon, aluminium, calcium, magnesium and boron oxides in the vitreous state; the rest can consist of alloy steel fibres. The bulk density of the insulation is 70 to 150 kg/m 3 . The product is highly resistant to temperature and to the action of chemicals, water, and acid and alkaline deactivation solutions. Its manufacture is fast and undemanding. It is designed for thermal insulation of pipes, tanks and valves in nuclear power plants. (M.D.). 2 figs

  20. Step tunneling enhanced asymmetry in metal-insulator-insulator-metal (MIIM) diodes for rectenna applications

    Science.gov (United States)

    Alimardani, N.; Conley, J. F.

    2013-09-01

    We combine nanolaminate bilayer insulator tunnel barriers (Al2O3/HfO2, HfO2/Al2O3, Al2O3/ZrO2) deposited via atomic layer deposition (ALD) with asymmetric work function metal electrodes to produce MIIM diodes with enhanced I-V asymmetry and non-linearity. We show that the improvements in MIIM devices are due to step tunneling rather than resonant tunneling. We also investigate conduction processes as a function of temperature in MIM devices with Nb2O5 and Ta2O5 high electron affinity insulators. For both Nb2O5 and Ta2O5 insulators, the dominant conduction process is established as Schottky emission at small biases and Frenkel-Poole emission at large biases. The energy depth of the traps that dominate Frenkel-Poole emission in each material are estimated.

  1. A short course on topological insulators band structure and edge states in one and two dimensions

    CERN Document Server

    Asbóth, János K; Pályi, András

    2016-01-01

    This course-based primer provides newcomers to the field with a concise introduction to some of the core topics in the emerging field of topological insulators. The aim is to provide a basic understanding of edge states, bulk topological invariants, and of the bulk--boundary correspondence with as simple mathematical tools as possible. The present approach uses noninteracting lattice models of topological insulators, building gradually on these to arrive from the simplest one-dimensional case (the Su-Schrieffer-Heeger model for polyacetylene) to two-dimensional time-reversal invariant topological insulators (the Bernevig-Hughes-Zhang model for HgTe). In each case the discussion of simple toy models is followed by the formulation of the general arguments regarding topological insulators. The only prerequisite for the reader is a working knowledge in quantum mechanics, the relevant solid state physics background is provided as part of this self-contained text, which is complemented by end-of-chapter problems.

  2. Vulcanization Kinetics and Mechanical Properties of Ethylene Propylene Diene Monomer Thermal Insulation

    Directory of Open Access Journals (Sweden)

    Mohamad Irfan Fathurrohman

    2015-07-01

    Full Text Available The vulcanization kinetics of Ethylene-propylene diene monomer (EPDM rubber thermal insulation was studied by using rheometer under isothermal condition at different temperatures. The rheometry analysis was used to determining the cure kinetic parameters and predicting the cure time of EPDM thermal insulation. The experimental results revealed that the curing curves of EPDM thermal insulation were marching and the optimum curing time decreased with increasing the temperature. The kinetic parameters were determined from the autocatalytic model showed close fitting with the experimental results, indicating suitability of autocatalytic model in characterizing the cure kinetics. The activation energy was determined from the autocatalytic model is 46.3661 kJ mol-1. The cure time were predicted from autocatalytic model and the obtained kinetic parameter by using the relationship among degree of conversion, cure temperature, and cure time. The predictions of cure time provide information for the actual curing characteristic of EPDM thermal insulation. The mechanical properties of EPDM thermal insulation with different vulcanization temperatures showed the same hardness, tensile strength and modulus at 300%, except at temperature 70 °C, while the elongation at breaking point decreased with increasing temperature of vulcanization. © 2015 BCREC UNDIP. All rights reservedReceived: 8th April 2014; Revised: 7th January 2015; Accepted: 16th January 2015How to Cite: Fathurrohman, M.I., Maspanger, D.R., Sutrisno, S. (2015. Vulcanization Kinetics and Mechanical Properties of Ethylene Propylene Diene Monomer Thermal Insulation. Bulletin of Chemi-cal Reaction Engineering & Catalysis, 10 (2, 104-110. (doi:10.9767/bcrec.10.2.6682.104-110Permalink/DOI: http://dx.doi.org/10.9767/bcrec.10.2.6682.104-110 

  3. Advances in Thermal Insulation. Vacuum Insulation Panels and Thermal Efficiency to Reduce Energy Usage in Buildings

    Energy Technology Data Exchange (ETDEWEB)

    Thorsell, Thomas

    2012-07-01

    We are coming to realize that there is an urgent need to reduce energy usage in buildings and it has to be done in a sustainable way. This thesis focuses on the performance of the building envelope; more precisely thermal performance of walls and super insulation material in the form of vacuum insulation. However, the building envelope is just one part of the whole building system, and super insulators have one major flaw: they are easily adversely affected by other problems in the built environment. Vacuum Insulation Panels are one fresh addition to the arsenal of insulation materials available to the building industry. They are composite material with a core and an enclosure which, as a composite, can reach thermal conductivities as low as 0.004 W/(mK). However, the exceptional performance relies on the barrier material preventing gas permeation, maintaining a near vacuum into the core and a minimized thermal bridge effect from the wrapping of barrier material round the edge of a panel. A serpentine edge is proposed to decrease the heat loss at the edge. Modeling and testing shows a reduction of 60 % if a reasonable serpentine edge is used. A diffusion model of permeation through multilayered barrier films with metallization coatings was developed to predict ultimate service life. The model combines numerical calculations with analytical field theory allowing for more precise determination than current models. The results using the proposed model indicate that it is possible to manufacture panels with lifetimes exceeding 50 years with existing manufacturing. Switching from the component scale to the building scale; an approach of integrated testing and modeling is proposed. Four wall types have been tested in a large range of environments with the aim to assess the hydrothermal nature and significance of thermal bridges and air leakages. The test procedure was also examined as a means for a more representative performance indicator than R-value (in USA). The

  4. Defect design of insulation systems for photovoltaic modules

    Science.gov (United States)

    Mon, G. R.

    1981-01-01

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

  5. An experimental study on thermal properties of composite insulation

    Energy Technology Data Exchange (ETDEWEB)

    Choi, Gyoung-Seok [Building and Urban Research Department, Korea Institute of Construction Technology, 2311 Daehwa-Dong, Ilsanseo-Gu, Goyang-Si, Gyeonggi-Do 411-712 (Korea); College of Architecture, Hanyang University, 17, Hangdang-Dong, Sungdong-Gu, Seoul 133-791 (Korea); Kang, Jae-Sik; Jeong, Young-Sun; Lee, Seung-Eon [Building and Urban Research Department, Korea Institute of Construction Technology, 2311 Daehwa-Dong, Ilsanseo-Gu, Goyang-Si, Gyeonggi-Do 411-712 (Korea); Sohn, Jang-Yeul [College of Architecture, Hanyang University, 17, Hangdang-Dong, Sungdong-Gu, Seoul 133-791 (Korea)

    2007-04-01

    In accordance with the insulation standards reinforced since 2001 and the compulsory standards on floor impact sound insulation that have been enforced since 2004, insulation materials for actual buildings have been converted to composite materials and new insulation materials have been released in the market. However, Korea is lagging behind the world in fundamental experimental studies and resources. In case of some composite insulation materials, there also have been problems of distorted performance occurring as a result of tests being conducted without having verification and evaluation on the accuracy and inaccuracy of such tests. Therefore, this study grasped the thermal properties of composite insulation materials using thermal conductivity test equipment by heat flux method, and performed quantitative evaluation on the measurement precision and uncertainty of composite materials. (author)

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

    International Nuclear Information System (INIS)

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

    2009-01-01

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

  7. The Wick-Concept for Thermal Insulation of Cold Piping

    DEFF Research Database (Denmark)

    Koverdynsky, Vit; Korsgaard, Vagn; Rode, Carsten

    2006-01-01

    the wick-concept in either of two variations: the self-drying or the self-sealing system. Experiments have been carried out using different variations of the two systems to investigate the conditions for exploiting the drying capabilities of the systems, and the results are presented. The results show......The wick-concept for thermal insulation of cold piping is based on capillary suction of a fiber fabric to remove excess water from the pipe surface by transporting it to the outer surface of the insulation. From the surface of the insulation jacket, the water will evaporate to the ambient air....... This will prevent long-term accumulation of moisture in the insulation material. The wick keeps the hydrophobic insulation dry, allowing it to maintain its thermal performance. The liquid moisture is kept only in the wick fabric. This article presents the principle of operation of cold pipe insulation using...

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

    International Nuclear Information System (INIS)

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

    2000-01-01

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

  9. Improvement of methods for calculation of sound insulation in buildings

    OpenAIRE

    Mašović, Draško B.

    2015-01-01

    The main object of this work are the methods for calculation of sound insulation based on the classical model of sound propagation in buildings and single-number rating of sound insulation. The aim of the work is inspection of the possibilities for improvement of standard methods for quantification and calculation of sound insulation, in order to achieve higher accuracy of the obtained numerical values and their correlation with subjective impression of the acoustic comfort in buildings. Proc...

  10. Design and construction of the mineral insulated magnets

    International Nuclear Information System (INIS)

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

    1978-01-01

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

  11. Fatigue effects in insulation materials for fusion magnets

    International Nuclear Information System (INIS)

    Rosenkranz, P.

    2000-12-01

    The mechanical properties of insulation materials for the superconducting magnets of ITER (International Thermonuclear Experimental Reactor) and future fusion plants, i.e. woven fiber reinforced composites, have been identified as an area of concern for the long-term operation of such magnets. The magnets will be subjected to fast neutron and γ-radiation over their lifetime, which influence the mechanical properties of the insulation materials. The ultimate tensile strength and, above all, the interlaminar shear strength and their performance under dynamic load, corresponding to the pulsed operation of a TOKAMAK-confinement system, are sensitive indicators of material failure in fiber-reinforced laminates especially at cryogenic temperatures. To simulate these conditions, low frequency fatigue measurements at 10 Hz were made at 77 K up to one million cycles. Tension-tension fatigue tests were performed according to ASTM D3479. However, due to the space limitations in all irradiation facilities, the tests have to be done on samples, which are considerably smaller than those required for standard test conditions. The influence of the specimen geometry on the ultimate tensile strength under static and dynamic load conditions was, therefore, investigated on fiber-reinforced plastics. They did not show any systematic trends as long as the sample thickness does not exceed the thickness recommended in ASTM D3479. The double lap shear test method was chosen for the shear experiments because of the symmetry of the specimen geometry under tensile load and the suitability for fatigue tests. Like almost every existing test procedure for the interlaminar shear strength, this test method does not provide for a completely uniform interlaminar shear stress distribution over a sizable region in the test section of the specimen. A scaling program combined with FE-simulations was, therefore, initiated to assess the influence of the length of the test section and of the sample

  12. Fibrous-Ceramic/Aerogel Composite Insulating Tiles

    Science.gov (United States)

    White, Susan M.; Rasky, Daniel J.

    2004-01-01

    Fibrous-ceramic/aerogel composite tiles have been invented to afford combinations of thermal-insulation and mechanical properties superior to those attainable by making tiles of fibrous ceramics alone or aerogels alone. These lightweight tiles can be tailored to a variety of applications that range from insulating cryogenic tanks to protecting spacecraft against re-entry heating. The advantages and disadvantages of fibrous ceramics and aerogels can be summarized as follows: Tiles made of ceramic fibers are known for mechanical strength, toughness, and machinability. Fibrous ceramic tiles are highly effective as thermal insulators in a vacuum. However, undesirably, the porosity of these materials makes them permeable by gases, so that in the presence of air or other gases, convection and gas-phase conduction contribute to the effective thermal conductivity of the tiles. Other disadvantages of the porosity and permeability of fibrous ceramic tiles arise because gases (e.g., water vapor or cryogenic gases) can condense in pores. This condensation contributes to weight, and in the case of cryogenic systems, the heat of condensation undesirably adds to the heat flowing to the objects that one seeks to keep cold. Moreover, there is a risk of explosion associated with vaporization of previously condensed gas upon reheating. Aerogels offer low permeability, low density, and low thermal conductivity, but are mechanically fragile. The basic idea of the present invention is to exploit the best features of fibrous ceramic tiles and aerogels. In a composite tile according to the invention, the fibrous ceramic serves as a matrix that mechanically supports the aerogel, while the aerogel serves as a low-conductivity, low-permeability filling that closes what would otherwise be the open pores of the fibrous ceramic. Because the aerogel eliminates or at least suppresses permeation by gas, gas-phase conduction, and convection, the thermal conductivity of such a composite even at

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

    Science.gov (United States)

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

    2018-04-01

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

  14. Novel load responsive multilayer insulation with high in-atmosphere and on-orbit thermal performance

    Science.gov (United States)

    Dye, S.; Kopelove, A.; Mills, G. L.

    2012-04-01

    Aerospace cryogenic systems require lightweight, high performance thermal insulation to preserve cryopropellants both pre-launch and on-orbit. Current technologies have difficulty meeting all requirements, and advances in insulation would benefit cryogenic upper stage launch vehicles, LH2 fueled aircraft and ground vehicles, and provide capabilities for sub-cooled cryogens for space-borne instruments and orbital fuel depots. This paper reports the further development of load responsive multilayer insulation (LRMLI) that has a lightweight integrated vacuum shell and provides high thermal performance both in-air and on-orbit. LRMLI is being developed by Quest Product Development and Ball Aerospace under NASA contract, with prototypes designed, built, installed and successfully tested. A 3-layer LRMLI blanket (0.63 cm thick, 77 K cold, 295 K hot) had a measured heat leak of 6.6 W/m2 in vacuum and 40.6 W/m2 in air at one atmosphere. In-air LRMLI has an 18× advantage over Spray On Foam Insulation (SOFI) in heat leak per thickness and a 16× advantage over aerogel. On-orbit LRMLI has a 78× lower heat leak than SOFI per thickness and 6× lower heat leak than aerogel. The Phase II development of LRMLI is reported with a modular, flexible, thin vacuum shell and improved on-orbit performance. Structural and thermal analysis and testing results are presented. LRMLI mass and thermal performance is compared to SOFI, aerogel and MLI over SOFI.

  15. Thermal Performance Testing of Cryogenic Multilayer Insulation with Silk Net Spacers

    International Nuclear Information System (INIS)

    Johnson, W L; Frank, D J; Nast, T C; Fesmire, J E

    2015-01-01

    Early comprehensive testing of cryogenic multilayer insulation focused on the use of silk netting as a spacer material. Silk netting was used for multiple test campaigns that were designed to provide baseline thermal performance estimates for cryogenic insulation systems. As more focus was put on larger systems, the cost of silk netting became a deterrent and most aerospace insulation firms were using Dacron (or polyester) netting spacers by the early 1970s. In the midst of the switch away from silk netting there was no attempt to understand the difference between silk and polyester netting, though it was widely believed that the silk netting provided slightly better performance. Without any better reference for thermal performance data, the silk netting performance correlations continued to be used. In order to attempt to quantify the difference between the silk netting and polyester netting, a brief test program was developed. The silk netting material was obtained from Lockheed Martin and was tested on the Cryostat-100 instrument in three different configurations, 20 layers with both single and double netting and 10 layers with single netting only. The data show agreement within 15 - 30% with the historical silk netting based correlations and show a substantial performance improvement when compared to previous testing performed using polyester netting and aluminum foil/fiberglass paper multilayer insulation. Additionally, the data further reinforce a recently observed trend that the heat flux is not directly proportional to the number of layers installed on a system. (paper)

  16. The Insulation for Machines Having a High Lifespan Expectancy, Design, Tests and Acceptance Criteria Issues

    Directory of Open Access Journals (Sweden)

    Olivier Barré

    2017-02-01

    provide insurance about lifespan, nor do any insulation tests incorporate all of the operating conditions: thermal, mechanical, moisture and chemical. Even if one manufacturer uses the standards compliance to demonstrate the quality of its realization; in the end, the successful use in operation remains an objective test. Thereafter, both customer and manufacturers will use the standards while knowing that such documents cannot fully satisfy their wishes. In one 20-year historical review, the authors will highlight the duration in insulation improvements and small breakthroughs in standards writing. High lifespan machines are not the main interest of standards. A large part of this publication is dedicated to the improvements of the insulation wall to achieve the lifespan. Even if the choice of raw materials is fundamental, the understanding of ageing phenomena also leads to improvements.

  17. BOA: Pipe asbestos insulation removal robot system

    International Nuclear Information System (INIS)

    Schempf, H.; Bares, J.; Schnorr, W.

    1995-01-01

    The BOA system is a mobile pipe-external robotic crawler used to remotely strip and bag asbestos-containing lagging and insulation materials (ACLIM) from various diameter pipes in (primarily) industrial installations. Steam and process lines within the DOE weapons complex warrant the use of a remote device due to the high labor costs and high level of radioactive contamination, making manual removal extremely costly and highly inefficient. Currently targeted facilities for demonstration and remediation are Fernald in Ohio and Oak Ridge in Tennessee

  18. Studies on Kondo insulating FeSi

    International Nuclear Information System (INIS)

    Bharathi, A.; Mani, Awadhesh; Ravindran, Nithya; Mathi Jaya, S.; Sundar, C.S.; Hariharan, Y.

    2000-01-01

    Temperature dependent electrical resistivity measurements have been carried out in Fe (1-x) Ru x Si and FeSi (1-x) Ge x to examine the robustness of the Kondo Insulating gap to substitution in the Fe and Si sublattices. The gap is seen to decrease with Ge substitution, while for Ru substitution the gap shows an initial decrease followed by an increase at higher concentration. The results can be understood in terms of the shift in the mobility edge due to disorder and/or pressure effects in combination with changes in band structure

  19. The infrared properties of reusable surface insulations.

    Science.gov (United States)

    Schmitt, R. J.; Linford, R. M. F.; Dillow, C. F.; Hughes, T. A.

    1973-01-01

    The total infrared scattering and absorption cross sections of both flexible and rigidized high temperature fibrous insulations have been measured. The methods for accomplishing these measurements are described. Infrared reflection and transmission spectra were obtained to study the dependence of the total cross sections on the spectral characteristics of the transported radiation. These results are applied to steady-state effective thermal conductivity measurements via a four-flux model of radiative heat transfer to separate the radiative component and to calculate the effective thermal conductivity under transient heating conditions. Data for both silica and mullite fibers are presented.

  20. Pilot cryo tunnel: Attachments, seals, and insulation

    Science.gov (United States)

    Wilson, J. F.; Ware, G. D.; Ramsey, J. W., Jr.

    1974-01-01

    Several different tests are described which simulated the actual configuration of a cryogenic wind tunnel operating at pressures up to 5 atmospheres (507 kPa) and temperatures from -320 F (78K) to 120 F (322K) in order to determine compatible bolting, adequate sealing, and effective insulating materials. The evaluation of flange attachments (continuous threaded studs) considered bolting based on compatible flanges, attachment materials, and prescribed bolt elongations. Various types of seals and seal configurations were studied to determine suitability and reusability under the imposed pressure and temperature loadings. The temperature profile was established for several materials used for structural supports.

  1. Graded thermal insulation layer systems; Gradierte Waermedaemmschichtsysteme

    Energy Technology Data Exchange (ETDEWEB)

    Leushake, U.; Krell, T. [Deutsche Forschungsanstalt fuer Luft- und Raumfahrt e.V. (DLR), Koeln (Germany). Inst. fuer Werkstoff-Forschung

    1996-12-31

    Graded thermal insulation systems reduce local stresses between two layers. Grading usually involves a concentration variation in a second phase but may also involve variations of the microstructure or chemical composition. The contribution discusses the application of this technique for thermal protection of turbine blades in aircraft propulsion systems. [Deutsch] Mit Hilfe gradierter Waermeschichtsysteme ist es moeglich die lokalen Spannungen zwischen zwei Schichten zu verringern. Die Gradierung umfasst meistens eine Variation des Gehaltes einer zweiten Phase, kann aber auch die Variation der Mikrostruktur oder der chemischen Zusammensetzung beinhalten. In diesem Beitrag wird auf die Anwendung als thermischer Schutz von Turbinenschaufeln fuer Flugtriebwerke eingegangen.

  2. Non-commutative tools for topological insulators

    International Nuclear Information System (INIS)

    Prodan, Emil

    2010-01-01

    This paper reviews several analytic tools for the field of topological insulators, developed with the aid of non-commutative calculus and geometry. The set of tools includes bulk topological invariants defined directly in the thermodynamic limit and in the presence of disorder, whose robustness is shown to have nontrivial physical consequences for the bulk states. The set of tools also includes a general relation between the current of an observable and its edge index, a relation that can be used to investigate the robustness of the edge states against disorder. The paper focuses on the motivations behind creating such tools and on how to use them.

  3. Creep of granulated loose-fill insulation

    DEFF Research Database (Denmark)

    Rasmussen, Torben Valdbjørn

    This report presents a proposal for a standardised method for creep tests and the necessary theoretical framework that can be used to describe creep of a granulated loose-fill material. Furthermore results from a round robin test are shown. The round robin test was carried out in collaboration...... with SP-Building Physics in Sweden and VTT Building Technology in Finland. For the round robin test a cellulosic fibre insulation material was used. The proposed standardised method for creep tests and theories are limited to cases when the granulated loose-fill material is exposed to a constant...

  4. 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.

  5. Using of Aerogel to Improve Thermal Insulating Properties of Windows

    Science.gov (United States)

    Valachova, Denisa; Zdrazilova, Nada; Panovec, Vladan; Skotnicova, Iveta

    2018-06-01

    For the best possible thermal-technical properties of building structures it is necessary to use materials with very low thermal conductivity. Due to the increasing thermal-technical requirements for building structures, the insulating materials are developed. One of the modern thermal insulating materials is so-called aerogel. Unfortunately, this material is not used in the field of external thermal insulation composite systems because of its price and its properties. The aim of this paper is to present possibilities of using this insulating material in the civil engineering - specifically a usage of aerogel in the production of windows.

  6. Analysis and comparison of magnetic sheet insulation tests

    Science.gov (United States)

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

    1994-05-01

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

  7. Thermo-Insulation Properties Of Hemp-Based Products

    Directory of Open Access Journals (Sweden)

    Lekavicius V.

    2015-02-01

    Full Text Available As known, many multi-purpose plants can be used in different industries. This research is focused on the possibilities to utilize hemp as feedstock for thermal insulation products. The most advantageous features of hemp insulation are associated with health and environmental safety. The thermal conductivity of commercially available hemp insulation products is comparable with that of other fibrous insulation materials; however, it is possible to develop new products that could be more efficient in terms of cost and due to other important features.

  8. Experiment on thermal insulation and sodium deposition of shield plug

    International Nuclear Information System (INIS)

    Hashiguchi, K.; Honda, M.; Shiratori, H.; Ozaki, O.; Suzuki, M.

    1986-01-01

    A series of experiments on temperature distribution and thermal insulation characteristics was conducted using a reduced scale model of LMFBR shield plug. Observation and measurement of sodium deposition were also conducted on the model after the experiment. The effect of annulus natural convection was clarified for temperature and the thermal insulation characteristics from evaluating the result. Temperature distribution analysis was conducted successfully by combining the general purpose structural analysis program NASTRAN and vertical annulus natural convection analysis program VANAC. Moreover, significant effect was substantiated for the annulus convection barrier to increase the thermal insulation performance, narrow horizontal gap structure to prevent sodium deposition and thermal insulation plates. (author)

  9. Acoustic topological insulator and robust one-way sound transport

    Science.gov (United States)

    He, Cheng; Ni, Xu; Ge, Hao; Sun, Xiao-Chen; Chen, Yan-Bin; Lu, Ming-Hui; Liu, Xiao-Ping; Chen, Yan-Feng

    2016-12-01

    Topological design of materials enables topological symmetries and facilitates unique backscattering-immune wave transport. In airborne acoustics, however, the intrinsic longitudinal nature of sound polarization makes the use of the conventional spin-orbital interaction mechanism impossible for achieving band inversion. The topological gauge flux is then typically introduced with a moving background in theoretical models. Its practical implementation is a serious challenge, though, due to inherent dynamic instabilities and noise. Here we realize the inversion of acoustic energy bands at a double Dirac cone and provide an experimental demonstration of an acoustic topological insulator. By manipulating the hopping interaction of neighbouring ’atoms’ in this new topological material, we successfully demonstrate the acoustic quantum spin Hall effect, characterized by robust pseudospin-dependent one-way edge sound transport. Our results are promising for the exploration of new routes for experimentally studying topological phenomena and related applications, for example, sound-noise reduction.

  10. Transport on the surface of a topological insulator

    International Nuclear Information System (INIS)

    Vargiamidis, V.; Vasilopoulos, P.

    2014-01-01

    We study theoretically dc and ac transport on the surface of a three-dimensional topological insulator when its time-reversal symmetry is broken. Starting with a Kubo formula, we derive an explicit expression for the dc Hall conductivity, valid for finite temperatures. At zero temperature this expression gives the dc half-quantum Hall conductivity, provided the Fermi level lies in the gap. Corrections when the Fermi level is outside the gap and scattering by impurities are quantified. The longitudinal conductivity is also examined. At finite frequencies, we find a modified Drude term in σ xx (ω) and logarithmic, frequency-dependent corrections in σ yx (ω). The ac Hall conductivity exhibits a robust logarithmic singularity for excitation energies equal to the gapwidth. For these energies, we also find that the power spectrum, which is pertinent to optical experiments, exhibits drastic increase. The Hall conductivity remains almost unaffected for temperatures up to approximately 300 K

  11. A Labview Based Leakage Current Monitoring System For HV Insulators

    Directory of Open Access Journals (Sweden)

    N. Mavrikakis

    2015-10-01

    Full Text Available In this paper, a Labview based leakage current monitoring system for High Voltage insulators is described. The system uses a general purpose DAQ system with the addition of different current sensors. The DAQ system consists of a chassis and hot-swappable modules. Through the proper design of current sensors, low cost modules operating with a suitable input range can be employed. Fully customizable software can be developed using Labview, allowing on-demand changes and incorporation of upgrades. Such a system provides a low cost alternative to specially designed equipment with the added advantage of maximum flexibility. Further, it can be modified to satisfy the specifications (technical and economical set under different scenarios. In fact, the system described in this paper has already been installed in the HV Lab of the TEI of Crete whereas a variation of it is currently in use in TALOS High Voltage Test Station.

  12. MHD pressure drop in ducts with imperfectly insulating coatings

    International Nuclear Information System (INIS)

    Malang, S.; Buehler, L.

    1994-08-01

    Liquid metal cooled blankets in fusion tokamak's are feasible only with electrically insulating coatings at the coolant channel walls. The requirements of such coatings are investigated and a simple analytical model is developed to determine the influence of imperfections in the coatings on the magneto-hydrodynamic pressure drop. This model is compared with the results of a 3D-MHD code based on the core flow approach. Both methods are in good agreement as long as the imperfections do not increase the pressure drop by more than 20%. The analytical model over-estimates the pressure drop for values larger than 20%. The importance of self-healing of coatings in case of cracking or flaking is quantified and an equation for the equilibrium conditions between the generation of imperfection and the healing of such spots is provided

  13. Hydrodynamic states of phonons in insulators

    Directory of Open Access Journals (Sweden)

    S.A. Sokolovsky

    2012-12-01

    Full Text Available The Chapman-Enskog method is generalized for accounting the effect of kinetic modes on hydrodynamic evolution. Hydrodynamic states of phonon system of insulators have been studied in a small drift velocity approximation. For simplicity, the investigation was carried out for crystals of the cubic class symmetry. It has been found that in phonon hydrodynamics, local equilibrium is violated even in the approximation linear in velocity. This is due to the absence of phonon momentum conservation law that leads to a drift velocity relaxation. Phonon hydrodynamic equations which take dissipative processes into account have been obtained. The results were compared with the standard theory based on the local equilibrium validity. Integral equations have been obtained for calculating the objects of the theory (including viscosity and heat conductivity. It has been shown that in low temperature limit, these equations are solvable by iterations. Steady states of the system have been considered and an expression for steady state heat conductivity has been obtained. It coincides with the famous result by Akhiezer in the leading low temperature approximation. It has been established that temperature distribution in the steady state of insulator satisfies a condition of heat source absence.

  14. Radiation effects on insulators for superconducting magnets

    International Nuclear Information System (INIS)

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

    1978-01-01

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

  15. Material-controlled dynamic vacuum insulation

    Science.gov (United States)

    Benson, D.K.; Potter, T.F.

    1996-10-08

    A compact vacuum insulation panel is described comprising a chamber enclosed by two sheets of metal, glass-like spaces disposed in the chamber between the sidewalls, and a high-grade vacuum in the chamber includes apparatus and methods for enabling and disabling, or turning ``on`` and ``off`` the thermal insulating capability of the panel. One type of enabling and disabling apparatus and method includes a metal hydride for releasing hydrogen gas into the chamber in response to heat, and a hydrogen grate between the metal hydride and the chamber for selectively preventing and allowing return of the hydrogen gas to the metal hydride. Another type of enabling and disabling apparatus and method includes a variable emissivity coating on the sheets of metal in which the emissivity is controllably variable by heat or electricity. Still another type of enabling and disabling apparatus and method includes metal-to-metal contact devices that can be actuated to establish or break metal-to-metal heat paths or thermal short circuits between the metal sidewalls. 25 figs.

  16. Variably insulating portable heater/cooler

    Science.gov (United States)

    Potter, T.F.

    1998-09-29

    A compact vacuum insulation panel is described comprising a chamber enclosed by two sheets of metal, glass-like spaces disposed in the chamber between the sidewalls, and a high-grade vacuum in the chamber includes apparatus and methods for enabling and disabling, or turning ``on`` and ``off`` the thermal insulating capability of the panel. One type of enabling and disabling apparatus and method includes a metal hydride for releasing hydrogen gas into the chamber in response to heat, and a hydrogen grate between the metal hydride and the chamber for selectively preventing and allowing return of the hydrogen gas to the metal hydride. Another type of enabling and disabling apparatus and method includes a variable emissivity coating on the sheets of metal in which the emissivity is controllably variable by heat or electricity. Still another type of enabling and disabling apparatus and method includes metal-to-metal contact devices that can be actuated to establish or break metal-to-metal heat paths or thermal short circuits between the metal sidewalls. 25 figs.

  17. Radiation-controlled dynamic vacuum insulation

    Science.gov (United States)

    Benson, D.K.; Potter, T.F.

    1995-07-18

    A compact vacuum insulation panel is described comprising a chamber enclosed by two sheets of metal, glass-like spaces disposed in the chamber between the sidewalls, and a high-grade vacuum in the chamber that includes apparatus and methods for enabling and disabling, or turning ``on`` and ``off`` the thermal insulating capability of the panel. One type of enabling and disabling apparatus and method includes a metal hydride for releasing hydrogen gas into the chamber in response to heat, and a hydrogen grate between the metal hydride and the chamber for selectively preventing and allowing return of the hydrogen gas to the metal hydride. Another type of enabling and disabling apparatus and method includes a variable emissivity coating on the sheets of metal in which the emissivity is controllably variable by heat or electricity. Still another type of enabling and disabling apparatus and method includes metal-to-metal contact devices that can be actuated to establish or break metal-to-metal heat paths or thermal short circuits between the metal sidewalls. 25 figs.

  18. Asymmetric Cherenkov acoustic reverse in topological insulators

    Science.gov (United States)

    Smirnov, Sergey

    2014-09-01

    A general phenomenon of the Cherenkov radiation known in optics or acoustics of conventional materials is a formation of a forward cone of, respectively, photons or phonons emitted by a particle accelerated above the speed of light or sound in those materials. Here we suggest three-dimensional topological insulators as a unique platform to fundamentally explore and practically exploit the acoustic aspect of the Cherenkov effect. We demonstrate that by applying an in-plane magnetic field to a surface of a three-dimensional topological insulator one may suppress the forward Cherenkov sound up to zero at a critical magnetic field. Above the critical field the Cherenkov sound acquires pure backward nature with the polar distribution differing from the forward one generated below the critical field. Potential applications of this asymmetric Cherenkov reverse are in the design of low energy electronic devices such as acoustic ratchets or, in general, in low power design of electronic circuits with a magnetic field control of the direction and magnitude of the Cherenkov dissipation.

  19. Observation of a phononic quadrupole topological insulator

    Science.gov (United States)

    Serra-Garcia, Marc; Peri, Valerio; Süsstrunk, Roman; Bilal, Osama R.; Larsen, Tom; Villanueva, Luis Guillermo; Huber, Sebastian D.

    2018-03-01

    The modern theory of charge polarization in solids is based on a generalization of Berry’s phase. The possibility of the quantization of this phase arising from parallel transport in momentum space is essential to our understanding of systems with topological band structures. Although based on the concept of charge polarization, this same theory can also be used to characterize the Bloch bands of neutral bosonic systems such as photonic or phononic crystals. The theory of this quantized polarization has recently been extended from the dipole moment to higher multipole moments. In particular, a two-dimensional quantized quadrupole insulator is predicted to have gapped yet topological one-dimensional edge modes, which stabilize zero-dimensional in-gap corner states. However, such a state of matter has not previously been observed experimentally. Here we report measurements of a phononic quadrupole topological insulator. We experimentally characterize the bulk, edge and corner physics of a mechanical metamaterial (a material with tailored mechanical properties) and find the predicted gapped edge and in-gap corner states. We corroborate our findings by comparing the mechanical properties of a topologically non-trivial system to samples in other phases that are predicted by the quadrupole theory. These topological corner states are an important stepping stone to the experimental realization of topologically protected wave guides in higher dimensions, and thereby open up a new path for the design of metamaterials.

  20. Transport of electric charge in insulators

    International Nuclear Information System (INIS)

    Lopez C, E.

    1979-01-01

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

  1. Insulation vacuum and beam vacuum overpressure release

    CERN Document Server

    Parma, V

    2009-01-01

    There is evidence that the incident of 19th September caused a high pressure build-up inside the cryostat insulation vacuum which the existing overpressure devices could not contain. As a result, high longitudinal forces acting on the insulation vacuum barriers developed and broke the floor and the floor fixations of the SSS with vacuum barriers. The consequent large longitudinal displacements of the SSS damaged chains of adjacent dipole cryo-magnets. Estimates of the helium mass flow and the pressure build- up experienced in the incident are presented together with the pressure build-up for an even more hazardous event, the Maximum Credible Incident (MCI). The strategy of limiting the maximum pressure by the installation of addition pressure relieve devices is presented and discussed. Both beam vacuum lines were ruptured during the incident in sector 3-4 giving rise to both mechanical damage and pollution of the system. The sequence, causes and effects of this damage will be briefly reviewed. We will then an...

  2. Higher-order topological insulators and superconductors protected by inversion symmetry

    Science.gov (United States)

    Khalaf, Eslam

    2018-05-01

    We study surface states of topological crystalline insulators and superconductors protected by inversion symmetry. These fall into the category of "higher-order" topological insulators and superconductors which possess surface states that propagate along one-dimensional curves (hinges) or are localized at some points (corners) on the surface. We provide a complete classification of inversion-protected higher-order topological insulators and superconductors in any spatial dimension for the 10 symmetry classes by means of a layer construction. We discuss possible physical realizations of such states starting with a time-reversal-invariant topological insulator (class AII) in three dimensions or a time-reversal-invariant topological superconductor (class DIII) in two or three dimensions. The former exhibits one-dimensional chiral or helical modes propagating along opposite edges, whereas the latter hosts Majorana zero modes localized to two opposite corners. Being protected by inversion, such states are not pinned to a specific pair of edges or corners, thus offering the possibility of controlling their location by applying inversion-symmetric perturbations such as magnetic field.

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

    CERN Document Server

    American Society for Testing and Materials. Philadelphia

    2007-01-01

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

  4. Magnon diffusion theory for the spin Seebeck effect in ferromagnetic and antiferromagnetic insulators

    Science.gov (United States)

    Rezende, Sergio M.; Azevedo, Antonio; Rodríguez-Suárez, Roberto L.

    2018-05-01

    In magnetic insulators, spin currents are carried by the elementary excitations of the magnetization: spin waves or magnons. In simple ferromagnetic insulators there is only one magnon mode, while in two-sublattice antiferromagnetic insulators (AFIs) there are two modes, which carry spin currents in opposite directions. Here we present a theory for the diffusive magnonic spin current generated in a magnetic insulator layer by a thermal gradient in the spin Seebeck effect. We show that the formulations describing magnonic perturbation using a position-dependent chemical potential and those using a magnon accumulation are completely equivalent. Then we develop a drift–diffusion formulation for magnonic spin transport treating the magnon accumulation governed by the Boltzmann transport and diffusion equations and considering the full boundary conditions at the surfaces and interfaces of an AFI/normal metal bilayer. The theory is applied to the ferrimagnetic yttrium iron garnet and to the AFIs MnF2 and NiO, providing good quantitative agreement with experimental data.

  5. Initial and Long-Term Movement of Cladding Installed Over Exterior Rigid Insulation

    Energy Technology Data Exchange (ETDEWEB)

    Baker, P.

    2014-09-01

    Changes in the International Energy Conservation Code (IECC) from 2009 to 2012 have resulted in the use of exterior rigid insulation becoming part of the prescriptive code requirements. With more jurisdictions adopting the 2012 IECC builders are going to finding themselves required to incorporate exterior insulation in the construction of their exterior wall assemblies. For thick layers of exterior insulation (levels greater than 1.5 inches), the use wood furring strips attached through the insulation back to the structure has been used by many contractors and designers as a means to provide a convenient cladding attachment location. However, there has been a significant resistance to its widespread implementation due to a lack of research and understanding of the mechanisms involved and potential creep effects of the assembly under the sustained dead load of a cladding. This research was an extension on previous research conducted by BSC in 2011, and 2012. Each year the understanding of the system discrete load component interactions, as well as impacts of environmental loading has increased. The focus of the research was to examine more closely the impacts of screw fastener bending on the total system capacity, effects of thermal expansion and contraction of materials on the compressive forces in the assembly, as well as to analyze a full years worth of cladding movement data from assemblies constructed in an exposed outdoor environment.

  6. Initial and Long-Term Movement of Cladding Installed Over Exterior Rigid Insulation

    Energy Technology Data Exchange (ETDEWEB)

    Baker, Peter [Building Science Corporation, Somerville, MA (United States)

    2014-09-01

    Changes in the International Energy Conservation Code (IECC) from 2009 to 2012 have resulted in the use of exterior rigid insulation becoming part of the prescriptive code requirements. With more jurisdictions adopting the 2012 IECC builders will be required to incorporate exterior insulation in the construction of their exterior wall assemblies. For thick layers of exterior insulation (levels greater than 1.5 inches), the use of wood furring strips attached through the insulation back to the structure has been used by many contractors and designers as a means to provide a convenient cladding attachment location. This research was an extension on previous research conducted by Building Science Corporation in 2011, and 2012. Each year the understanding of the system discrete load component interactions, as well as impacts of environmental loading, has increased. The focus of the research was to examine more closely the impacts of screw fastener bending on the total system capacity, effects of thermal expansion and contraction of materials on the compressive forces in the assembly, as well as to analyze a full year’s worth of cladding movement data from assemblies constructed in an exposed outdoor environment.

  7. Simulation of Contamination Deposition on Typical Shed Porcelain Insulators

    Directory of Open Access Journals (Sweden)

    Yukun Lv

    2017-07-01

    Full Text Available The contamination deposition characteristics of insulators can be used in the development of antifouling work. Using COMSOL software, numerical simulations on the pollution-deposited performance of a porcelain three-umbrella insulator and porcelain bell jar insulator in a wind tunnel were conducted, and the simulated results were compared with the tested results. The comparison shows that the deposit amount is consistent with the order of magnitude and presents a similar tendency with Direct Current (DC voltage variation; then the rationality of the simulation is verified. Based on these results, simulations of the natural contamination deposition on porcelain insulators and the distribution of pollution along the umbrella skirt were performed. The results indicates that, under a same wind speed, contamination of the porcelain three-umbrella insulator and porcelain bell jar insulator under DC voltage was positively correlated with the particle size. With the same particle size, the proportion of the deposit amount under DC voltage (NSDDDC to the deposit amount under AC voltage (NSDDAC of both insulators decreases with the increase in wind speed. However, the ratio increases as particle size increase. At a small wind speed, the deposit amount along the umbrella skirt of the two insulators displays a U-shaped distribution under DC voltage while there is little difference in the contamination amount of each skirt under Alternating Current (AC voltage.

  8. Simple test for physical stability of cryogenic tank insulation

    Science.gov (United States)

    Rossello, D.

    1968-01-01

    Qualitative test determines the ability of insulation liners used on liquid hydrogen tanks to withstand stresses produced by the thermal shocks imparted to the insulation during tank filling and drainage. Test specimens are bonded to metal plates with a low thermal expansion coefficient and are immersed in liquid hydrogen.

  9. 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.

  10. 16 CFR 460.2 - What is home insulation.

    Science.gov (United States)

    2010-01-01

    ... 16 Commercial Practices 1 2010-01-01 2010-01-01 false What is home insulation. 460.2 Section 460.2 Commercial Practices FEDERAL TRADE COMMISSION TRADE REGULATION RULES LABELING AND ADVERTISING OF HOME..., semirigid, flexible, or loose-fill form. Home insulation is for use in old or new homes, condominiums...

  11. Stator insulation systems for medium voltage PWM drives fed motors

    International Nuclear Information System (INIS)

    Gao, G.; Chen, W.

    2005-01-01

    This paper presents the partial results of a research project that studied the impact of medium voltage PWM ASD (adjustable speed drives) on motor stator insulation system. The findings from this study/ investigation have aided designers to improve the robustness of the insulation system used for ASD-fed motors, based on accelerated laboratory tests. (author)

  12. Heat resistance insulation for NPP pipelines and components

    International Nuclear Information System (INIS)

    Yurchenko, V.G.; Nazarova, G.A.; Popov, A.M.; Matveeva, N.F.

    1986-01-01

    To insulate hot surfaces of NPP process equipment and pipes it is suggested to use heat resistant insulation of foam aminoimides (FAI). Relative toxicity of aceton and acetaldehyd evolved from FAI in the process of thermal and thermal-oxidative break-down was determined. FAI can be used at 200 deg C

  13. 52 KILN EFFICIENCY AND INSULATION. Anthony Obiy Etuokwu ...

    African Journals Online (AJOL)

    HP-G61

    52. KILN EFFICIENCY AND INSULATION. Anthony Obiy Etuokwu. Department of Fine and Industrial Arts,. Niger Delta University,. Wilberforce Island, Bayelsa State. etuokwutony@yahoo.com. Introduction. The kiln is an insulating fire chamber that has the ability to retain the heat that is generated into it, and utilizes such heat ...

  14. On new electromagnetic waves in a multicomponent insulator

    NARCIS (Netherlands)

    Dubovik, V. M.

    The dispersion equation for additional transverse electromagnetic waves in a multicomponent amorphous insulator is analyzed in the vicinity of a narrow absorption line. Such waves can be excited due to spatial dispersion associated with fluctuation of the polarizability of insulator molecules. The

  15. Comparative study of thermal insulation boards from leaf and bark ...

    African Journals Online (AJOL)

    Thus, several researches have succeeded in using these plants and agro waste fibres in developing renewable and environmentally friendly thermal insulation products. The aim of this study was to compare the performance of insulation boards made from leave and bark fibres of Pilios tigma thonningii L.in terms of density, ...

  16. Insulating modernism isolated and non-isolated thermodynamics in architecture

    CERN Document Server

    Moe, Kiel

    2014-01-01

    What is the best way to achieve sustainable energy savings in buildings? The mainstream construction industry has been saying for decades: it's insulation. Today there is a growing movement among architects who claim that, by contrast, it isintelligent design thatprovides the best energetic results. This book describes the history, theory and facts of the mainstream insulation technology and the emerging alternative design approaches.

  17. Design of the Yang magnetically-insulated transmission line

    International Nuclear Information System (INIS)

    Gu Yuanchao; Song Shenyi

    2002-01-01

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

  18. Bulk and edge spin transport in topological magnon insulators

    NARCIS (Netherlands)

    Rückriegel, A.; Brataas, A.; Duine, R.A.

    2018-01-01

    We investigate the spin transport properties of a topological magnon insulator, a magnetic insulator characterized by topologically nontrivial bulk magnon bands and protected magnon edge modes located in the bulk band gaps. Employing the Landau-Lifshitz-Gilbert phenomenology, we calculate the spin

  19. Optimization of insulation of a linear Fresnel collector

    Science.gov (United States)

    Ardekani, Mohammad Moghimi; Craig, Ken J.; Meyer, Josua P.

    2017-06-01

    This study presents a simulation based optimization study of insulation around the cavity receiver of a Linear Fresnel Collector. This optimization study focuses on minimizing heat losses from a cavity receiver (maximizing plant thermal efficiency), while minimizing insulation cross-sectional area (minimizing material cost and cavity dead load), which leads to a cheaper and thermally more efficient LFC cavity receiver.

  20. Polymer-Reinforced, Non-Brittle, Lightweight Cryogenic Insulation

    Science.gov (United States)

    Hess, David M.

    2013-01-01

    The primary application for cryogenic insulating foams will be fuel tank applications for fueling systems. It is crucial for this insulation to be incorporated into systems that survive vacuum and terrestrial environments. It is hypothesized that by forming an open-cell silica-reinforced polymer structure, the foam structures will exhibit the necessary strength to maintain shape. This will, in turn, maintain the insulating capabilities of the foam insulation. Besides mechanical stability in the form of crush resistance, it is important for these insulating materials to exhibit water penetration resistance. Hydrocarbon-terminated foam surfaces were implemented to impart hydrophobic functionality that apparently limits moisture penetration through the foam. During the freezing process, water accumulates on the surfaces of the foams. However, when hydrocarbon-terminated surfaces are present, water apparently beads and forms crystals, leading to less apparent accumulation. The object of this work is to develop inexpensive structural cryogenic insulation foam that has increased impact resistance for launch and ground-based cryogenic systems. Two parallel approaches will be pursued: a silica-polymer co-foaming technique and a post foam coating technique. Insulation characteristics, flexibility, and water uptake can be fine-tuned through the manipulation of the polyurethane foam scaffold. Silicate coatings for polyurethane foams and aerogel-impregnated polyurethane foams have been developed and tested. A highly porous aerogel-like material may be fabricated using a co-foam and coated foam techniques, and can insulate at liquid temperatures using the composite foam

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

    International Nuclear Information System (INIS)

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

    1982-01-01

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

  2. Local Thermal Insulating Materials For Thermal Energy Storage ...

    African Journals Online (AJOL)

    Thermal insulation is one of the most important components of a thermal energy storage system. In this paper the thermal properties of selected potential local materials which can be used for high temperature insulation are presented. Thermal properties of seven different samples were measured. Samples consisted of: ...

  3. Innovative Retrofit Insulation Strategies for Concrete Masonry Foundations

    Energy Technology Data Exchange (ETDEWEB)

    Huelman, P. [Univ. of Minnesota, St. Paul, MN (United States). NorthernSTAR Building America Partnership; Goldberg, L. [Univ. of Minnesota, St. Paul, MN (United States). NorthernSTAR Building America Partnership; Jacobson, R. [Univ. of Minnesota, St. Paul, MN (United States). NorthernSTAR Building America Partnership

    2015-05-06

    This study was designed to test a new approach for foundation insulation retrofits, with the goal of demonstrating improved moisture control, improved occupant comfort, and reduced heat loss. Because conducting experimental research on existing below-grade assemblies is very difficult, most of the results are based on simulations. The retrofit approach consists of filling open concrete block cores with an insulating material and adding R-10 exterior insulation that extends 1 ft below grade. The core fill is designed to improve the R-value of the foundation wall and increase the interior wall surface temperature, but more importantly to block convection currents that could otherwise increase moisture loads on the foundation wall and interior space. The exterior insulation significantly reduces heat loss through the most exposed part of the foundation and further increases the interior wall surface temperature. This improves occupant comfort and decreases the risk of condensation. Such an insulation package avoids the full-depth excavation necessary for exterior insulation retrofits, reduces costs, and eliminates the moisture and indoor air quality risks associated with interior insulation retrofits. Retrofit costs for the proposed approach were estimated at roughly half those of a full-depth exterior insulation retrofit.

  4. Test method for measuring insulation values of cryogenic pipes

    NARCIS (Netherlands)

    Velthuis, J.F.M.; Blokland, H.; Klaver, B.W.; Beld, C. van de

    2010-01-01

    In this paper a large-area heat flux and temperature sensor (HFT) is used for the evaluation of the insulation value of cryogenic pipes. The HFT is flexible and clamp-on. The test method is relatively simple and can be used in-situ. The HFT makes it possible to monitor insulation performance over

  5. Fatigue behavior of an insulation system for the ITER magnets

    International Nuclear Information System (INIS)

    Prokopec, R.; Humer, K.; Weber, H.W.

    2006-01-01

    The application of glass-fiber reinforced plastics as insulation materials for fusion magnet coils (e.g. the Toroidal Field Coils of ITER) requires the full characterization of their mechanical performance under ITER-relevant conditions. One of the methods of testing material's response under dynamic load is the tension-tension fatigue procedure. This test can be used to simulate the pulsed tokamak-operation of the ITER coils over a lifetime of more than 20 years. Furthermore, it provides information on the maximum tensile or shear stress in the ITER-relevant range of 10 4 -10 5 cycles. In order to simulate the operation conditions of ITER as closely as possible, several fatigue parameters can be set in the test programme, e.g., the minimum-to-peak stress ratio R and the frequency ν of the sinusoidal load function. Further, the fatigue process can be run under load or strain control. All of these parameters may influence the mechanical response of the insulation system under cyclic load. Therefore, it is highly desirable to investigate the influence of test parameter variations on the measured stress-lifetime diagrams. The investigations were performed at 77 K using an industrial glass-fiber reinforced composite impregnated with epoxy resin. For both the load and the strain controlled mode, R-values of 0.3 and 0.5 and a frequency of 10 Hz were chosen. The results showed almost no deviations in the lifetime behavior between the load and the strain controlled mode, up to the ITER specified number of pulses, i.e. 3 x 10 4 cycles. Beyond this point, the residual strength levels were lower by 5-30 % under strain control than under load control. This effect is more pronounced at higher cycle numbers and for lower R-ratios. (author)

  6. Insulation Characteristics of Sisal Fibre/Epoxy Composites

    Directory of Open Access Journals (Sweden)

    A. Shalwan

    2017-01-01

    Full Text Available Using natural fibres in civil engineering is the aim of many industrial and academics sectors to overcome the impact of synthetic fibres on environments. One of the potential applications of natural fibres composites is to be implemented in insulation components. Thermal behaviour of polymer composites based on natural fibres is recent ongoing research. In this article, thermal characteristics of sisal fibre reinforced epoxy composites are evaluated for treated and untreated fibres considering different volume fractions of 0–30%. The results revealed that the increase in the fibre volume fraction increased the insulation performance of the composites for both treated and untreated fibres. More than 200% insulation rate was achieved at the volume fraction of 20% of treated sisal fibres. Untreated fibres showed about 400% insulation rate; however, it is not recommended to use untreated fibres from mechanical point of view. The results indicated that there is potential of using the developed composites for insulation purposes.

  7. Correlation among ESDD, NSDD and leakage current in distribution insulators

    International Nuclear Information System (INIS)

    Montoya, G.; Ramirez, I.; Montoya, J.I.

    2004-01-01

    The maintenance of distribution networks is more effective if the insulation contamination levels are known. The selection of measuring methods of pollution levels is then crucial. The relationship between several evaluation methods of pollution levels and the operating behaviour of several insulator profiles in a polluted zone is described. Laboratory tests were carried out to reproduce pollution levels found in the field. The quantity of non-soluble materials deposited over the insulators' surface affect the magnitude of the leakage current generated over a contaminated insulator. The relationship that defines leakage current with respect to the equivalent salt deposit density (ESDD) level for a specific non-soluble material level is almost linear, from which it is possible to develop a relationship between them for each insulator. (author)

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

    International Nuclear Information System (INIS)

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

    2003-01-01

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

  9. Crosslinking of wire and cable insulation using electron accelerators

    International Nuclear Information System (INIS)

    Feng Yongxiang; Ma Zueteh

    1992-01-01

    Radiation crosslinking of wire and cable insulation is a well-established technology that is widely used in industry. The advantages of radiation crosslinking over chemical crosslinking have helped maintain its steady growth. Since successful utilization of electron beam processing relies on the formulation of compounds used in insulation, the radiation crosslinking of various polymers is reviewed. The handling technology for crosslinking wire and cable insulation and the throughput capacity of electron beam processors are also discussed. More than 30% of the industrial electron accelerators in the world are used for the radiation crosslinking of wire and cable insulation. Prospects of increased use of electron accelerators for crosslinking of wire and cable insulation are very good. (orig.)

  10. ONLINE TECHNOLOGICAL MONITORING OF INSULATION DEFECTS IN ENAMELED WIRES

    Directory of Open Access Journals (Sweden)

    V. M. Zolotaryov

    2017-08-01

    Full Text Available In this paper the authors used non-destructive technological monitoring of defects insulation enameled wire with poliimid polymer. The paper is devoted to the statistical method for processing, comparison and analysis of results of measurements of parameters of insulation of enameled wire because of mathematical model of trend for application in active technological monitoring is developed; the recommendations for parameters of such monitoring are used. It is theoretically justified and the possibility of determination of dependence of the error on the velocity of movement of a wire for want of quantifying of defects in enameled insulation by non-destructive tests by high voltage. The dependence of average value of amount of defects for enameled wire with two-sheeted poliimid insulation in a range of nominal diameter 0.56 mm is experimentally determined. The technological monitoring purpose is to reduce the quantifying defects of enameled insulation.

  11. Further considerations for damping in heavily insulated pipe systems

    International Nuclear Information System (INIS)

    Anderson, M.J.; Lindquist, M.R.; Severud, L.K.

    1985-01-01

    Over the past several years a body of test data has been accumulated which demonstrates that damping in small diameter heavily insulated pipe systems is much larger than presently recommended by Regulatory Guide 1.61. This data is generally based on pipe systems using a stand-off insulation design with a heater annulus. Additional tests have how been completed on similar pipe systems using a strap-on insulation design without the heater annulus. Results indicate some reduction in damping over the stand-off designs. Test data has also been obtained on a larger sixteen-inch diameter heavily insulated pipe system. Results of these two additional test series are presented. Revised damping values for seismic design of heavily insulated pipe systems are then recommended

  12. Further considerations for damping in heavily insulated pipe systems

    International Nuclear Information System (INIS)

    Anderson, M.J.; Lindquist, M.R.; Severud, L.K.

    1985-01-01

    Over the past several years a body of test data has been accumulated which demonstrates that damping in small diameter heavily insulated pipe systems is much larger than presently recommended by Regulatory Code 1.61. This data is generally based on pipe systems using a stand-off insulation design with a heater annulus. Additional tests have now been completed on similar pipe systems using a strap-on insulation design without the heater annulus. Results indicate some reduction in damping over the stand-off designs. Test data has also been obtained on a larger sixteen-inch diameter heavily insulated pipe system. Results of these two additional test series are presented. Revised damping values for seismic design for heavily insulated pipe systems are then recommended

  13. Thermal insulation system design and fabrication specification (nuclear) for the Clinch River Breeder Reactor plant

    International Nuclear Information System (INIS)

    1978-01-01

    This specification defines the design, analysis, fabrication, testing, shipping, and quality requirements of the Insulation System for the Clinch River Breeder Reactor Plant (CRBRP), near Oak Ridge, Tennessee. The Insulation System includes all supports, convection barriers, jacketing, insulation, penetrations, fasteners, or other insulation support material or devices required to insulate the piping and equipment cryogenic and other special applications excluded. Site storage, handling and installation of the Insulation System are under the cognizance of the Purchaser

  14. Topological insulators and superconductors: tenfold way and dimensional hierarchy

    International Nuclear Information System (INIS)

    Ryu, Shinsei; Schnyder, Andreas P; Furusaki, Akira; Ludwig, Andreas W W

    2010-01-01

    It has recently been shown that in every spatial dimension there exist precisely five distinct classes of topological insulators or superconductors. Within a given class, the different topological sectors can be distinguished, depending on the case, by a Z or a Z 2 topological invariant. This is an exhaustive classification. Here we construct representatives of topological insulators and superconductors for all five classes and in arbitrary spatial dimension d, in terms of Dirac Hamiltonians. Using these representatives we demonstrate how topological insulators (superconductors) in different dimensions and different classes can be related via 'dimensional reduction' by compactifying one or more spatial dimensions (in 'Kaluza-Klein'-like fashion). For Z-topological insulators (superconductors) this proceeds by descending by one dimension at a time into a different class. The Z 2 -topological insulators (superconductors), on the other hand, are shown to be lower-dimensional descendants of parent Z-topological insulators in the same class, from which they inherit their topological properties. The eightfold periodicity in dimension d that exists for topological insulators (superconductors) with Hamiltonians satisfying at least one reality condition (arising from time-reversal or charge-conjugation/particle-hole symmetries) is a reflection of the eightfold periodicity of the spinor representations of the orthogonal groups SO(N) (a form of Bott periodicity). Furthermore, we derive for general spatial dimensions a relation between the topological invariant that characterizes topological insulators and superconductors with chiral symmetry (i.e., the winding number) and the Chern-Simons invariant. For lower-dimensional cases, this formula relates the winding number to the electric polarization (d=1 spatial dimensions) or to the magnetoelectric polarizability (d=3 spatial dimensions). Finally, we also discuss topological field theories describing the spacetime theory of

  15. Improving the reliability of stator insulation system in rotating machines

    International Nuclear Information System (INIS)

    Gupta, G.K.; Sedding, H.G.; Culbert, I.M.

    1997-01-01

    Reliable performance of rotating machines, especially generators and primary heat transport pump motors, is critical to the efficient operation on nuclear stations. A significant number of premature machine failures have been attributed to the stator insulation problems. Ontario Hydro has attempted to assure the long term reliability of the insulation system in critical rotating machines through proper specifications and quality assurance tests for new machines and periodic on-line and off-line diagnostic tests on machines in service. The experience gained over the last twenty years is presented in this paper. Functional specifications have been developed for the insulation system in critical rotating machines based on engineering considerations and our past experience. These specifications include insulation stress, insulation resistance and polarization index, partial discharge levels, dissipation factor and tip up, AC and DC hipot tests. Voltage endurance tests are specified for groundwall insulation system of full size production coils and bars. For machines with multi-turn coils, turn insulation strength for fast fronted surges in specified and verified through tests on all coils in the factory and on samples of finished coils in the laboratory. Periodic on-line and off-line diagnostic tests were performed to assess the condition of the stator insulation system in machines in service. Partial discharges are measured on-line using several techniques to detect any excessive degradation of the insulation system in critical machines. Novel sensors have been developed and installed in several machines to facilitate measurements of partial discharges on operating machines. Several off-line tests are performed either to confirm the problems indicated by the on-line test or to assess the insulation system in machines which cannot be easily tested on-line. Experience with these tests, including their capabilities and limitations, are presented. (author)

  16. Protection against cold in prehospital care-thermal insulation properties of blankets and rescue bags in different wind conditions.

    Science.gov (United States)

    Henriksson, Otto; Lundgren, J Peter; Kuklane, Kalev; Holmér, Ingvar; Bjornstig, Ulf

    2009-01-01

    In a cold, wet, or windy environment, cold exposure can be considerable for an injured or ill person. The subsequent autonomous stress response initially will increase circulatory and respiratory demands, and as body core temperature declines, the patient's condition might deteriorate. Therefore, the application of adequate insulation to reduce cold exposure and prevent body core cooling is an important part of prehospital primary care, but recommendations for what should be used in the field mostly depend on tradition and experience, not on scientific evidence. The objective of this study was to evaluate the thermal insulation properties in different wind conditions of 12 different blankets and rescue bags commonly used by prehospital rescue and ambulance services. The thermal manikin and the selected insulation ensembles were setup inside a climatic chamber in accordance to the modified European Standard for assessing requirements of sleeping bags. Fans were adjusted to provide low (value, Itr (m2 C/Wclo; where C = degrees Celcius, and W = watts), was calculated from ambient air temperature (C), manikin surface temperature (C), and heat flux (W/m2). In the low wind condition, thermal insulation of the evaluated ensembles correlated to thickness of the ensembles, ranging from 2.0 to 6.0 clo (1 clo = 0.155 m2 C/W), except for the reflective metallic foil blankets that had higher values than expected. In moderate and high wind conditions, thermal insulation was best preserved for ensembles that were windproof and resistant to the compressive effect of the wind, with insulation reductions down to about 60-80% of the original insulation capacity, whereas wind permeable and/or lighter materials were reduced down to about 30-50% of original insulation capacity. The evaluated insulation ensembles might all be used for prehospital protection against cold, either as single blankets or in multiple layer combinations, depending on ambient temperatures. However, with extended

  17. Moisture buffer capacity of different insulation materials

    DEFF Research Database (Denmark)

    Peuhkuri, Ruut Hannele; Rode, Carsten; Hansen, Kurt Kielsgaard

    2004-01-01

    . In the isothermal tests the material samples were exposed to the same change in the relative humidity of the ambient air on both sides, while the samples were exposed to variations in relative humidity only on the cold side in the non-isothermal tests. The results of these rather different measurement principles...... lead to more durable constructions. In this paper, a large range of very different thermal insulation materials have been tested in specially constructed laboratory facilities to determine their moisture buffer capacity. Both isothermal and nonisothermal experimental set-ups have been used...... are discussed, and different ways are presented how to determine the moisture buffer capacity of the materials using partly standard material parameters and partly parameters determined from the actual measurements. The results so far show that the determination of moisture buffer capacity is very sensitive...

  18. Axial grazing collisions with insulator surfaces

    Energy Technology Data Exchange (ETDEWEB)

    Gravielle, M.S. [Instituto de Astronomia y Fisica del Espacio (IAFE), Consejo Nacional de Investigaciones Cientificas y Tecnicas, Casilla de Correo 67, Sucursal 28, 1428 Buenos Aires (Argentina) and Departamento de Fisica, FCEN, Universidad de Buenos Aires (Argentina)]. E-mail: msilvia@iafe.uba.ar; Miraglia, J.E. [Instituto de Astronomia y Fisica del Espacio (IAFE), Consejo Nacional de Investigaciones Cientificas y Tecnicas, Casilla de Correo 67, Sucursal 28, 1428 Buenos Aires (Argentina); Departamento de Fisica, FCEN, Universidad de Buenos Aires (Argentina)

    2007-05-15

    Electron capture and emission processes from insulator surfaces produced by grazing impact of fast ions are investigated under axial incidence conditions. For crystal surfaces we develop a model based on distorted wave methods, which allows us to express the coherent transition amplitude along the projectile path as a sum of atomic amplitudes, each one associated with a different lattice site. The method is applied to 100 keV protons colliding with LiF surfaces. For electron transitions from a given initial crystal state, the probabilities display strong interference effects as a function of the crystal orientation. But the interference patterns disappear when these partial probabilities are added to derive the total probability from the surface band.

  19. Axial grazing collisions with insulator surfaces

    International Nuclear Information System (INIS)

    Gravielle, M.S.; Miraglia, J.E.

    2007-01-01

    Electron capture and emission processes from insulator surfaces produced by grazing impact of fast ions are investigated under axial incidence conditions. For crystal surfaces we develop a model based on distorted wave methods, which allows us to express the coherent transition amplitude along the projectile path as a sum of atomic amplitudes, each one associated with a different lattice site. The method is applied to 100 keV protons colliding with LiF surfaces. For electron transitions from a given initial crystal state, the probabilities display strong interference effects as a function of the crystal orientation. But the interference patterns disappear when these partial probabilities are added to derive the total probability from the surface band

  20. Effects of pressure on doped Kondo insulators

    International Nuclear Information System (INIS)

    Lee, Chengchung; Xu, Wang

    1999-08-01

    The effects of pressure on the doped Kondo insulators (KI) are studied in the framework of the slave-boson mean-field theory under the coherent potential approximation (CPA). A unified picture for both electron-type KI and hole-type KI is presented. The density of states of the f-electrons under the applied pressures and its variation with the concentration of the Kondo holes are calculated self-consistently. The specific heat coefficient, the zero-temperature magnetic susceptibility as well as the low temperature electric resistivity of the doped KI under various pressures are obtained. The two contrasting pressure-dependent effects observed in the doped KI systems can be naturally explained within a microscopic model. (author)

  1. A decking for erecting an insulating connector

    Energy Technology Data Exchange (ETDEWEB)

    Chuprikov, A Ye; Lagutin, V I; Sklyarov, A A; Sukhanov, G V

    1983-01-01

    The decking includes a parachute like dome, made of a material impenetrable to air, an air penetrable hood, attachment elements and a branch pipe for supplying the filler. To improve the sealing of the insulating connector upon contact with the walls and the roof of the drift being isolated and to reduce the labor intensity of operations, it is equipped with a housing made in the form of a cylinder from a material impenetrable to water, an advancible vertical upright and a spring loaded panel. The housing is installed between the parachute like dome and the air penetrable hood. The extendible vertical upright is installed on the side of the air penetrable hood and by means of a movable rack mechanism is kinematically linked with the spring loaded panel, installed with the capability of interacting with the air penetrable hood. The spring loaded plate is made in the form of perforated plates which have a telescopic disengagement in the horizontal plane.

  2. Functionality of Ventilated Facades: Protection of Insulation

    Directory of Open Access Journals (Sweden)

    Petrichenko Mikhail

    2016-01-01

    Full Text Available This article discusses about methods of construction of the ventilated facades. The ventilated facade is not only the element of facing, it is the supporting structure. Their main objective - creation of air ventilating space between a facade and an external wall of the building. Moving of air in this gap protects a heater from destruction, interfering with a moisture congestion. In addition, the ventilated facade protect the building from aggressive influence of external environment, have a sound and thermal insulation properties. There are several problems of systems of the ventilated facades connected with an application of a heater. For more effective using it is necessary to minimize contact of a heater with environment.

  3. CFC alternatives for thermal insulation foams

    Energy Technology Data Exchange (ETDEWEB)

    Shankland, I.R. (Allied-Signal Inc., Buffalo, NY (US))

    1990-03-01

    Low density polymeric foam materials expanded with chlorofluorocarbon (CFC) blowing agents have found widespread use as highly efficient thermal insulation materials in the construction, refrigeration appliance and transportation industries. The advent of regulations which are reducing the production and consumption of the fully halogenated CFCs for environmental reasons has prompted the development of environmentally acceptable substitutes for the CFC blowing agents. This paper summarizes the physical properties and performance of the leading alternatives for CFC-11, which is used to expand rigid polyurethane and polyisocyanurate foams, and the leading alternatives for CFC-12 which is used to expand extruded polystyrene board foam. Although the alternatives, HCFC-123 and HCFC-14lb for CFC-11 and HCFC142b and HCFC-124 for CFC-12, are not perfect matches from the performance viewpoint, they represent the optimum choice given the constraints on environmental acceptability, toxicity, flammability and performance. (author).

  4. High sensitivity thermal sensors on insulating diamond

    Energy Technology Data Exchange (ETDEWEB)

    Job, R. [Fernuniversitaet Hagen (Gesamthochschule) (Germany). Electron. Devices; Denisenko, A.V. [Fernuniversitaet Hagen (Gesamthochschule) (Germany). Electron. Devices; Zaitsev, A.M. [Fernuniversitaet Hagen (Gesamthochschule) (Germany). Electron. Devices; Melnikov, A.A. [Belarussian State Univ., Minsk (Belarus). HEII and FD; Werner, M. [VDI/VDE-IT, Teltow (Germany); Fahrner, W.R. [Fernuniversitaet Hagen (Gesamthochschule) (Germany). Electron. Devices

    1996-12-15

    Diamond is a promising material to develop sensors for applications in harsh environments. To increase the sensitivity of diamond temperature sensors the effect of thermionic hole emission (TE) over an energetic barrier formed in the interface between highly boron-doped p-type and intrinsic insulating diamond areas has been suggested. To study the TE of holes a p-i-p diode has been fabricated and analyzed by electrical measurements in the temperature range between 300 K and 700 K. The experimental results have been compared with numerical simulations of its electrical characteristics. Based on a model of the thermionic emission of carriers into an insulator it has been suggested that the temperature sensitivity of the p-i-p diode on diamond is strongly affected by the re-emission of holes from a group of donor-like traps located at a level of 0.7-1.0 eV above the valence band. The mechanism of thermal activation of the current includes a spatial redistribution of the potential, which results in the TE regime from a decrease of the immobilized charge of the ionized traps within the i-zone of the diode and the correspondent lowering of the forward biased barrier. The characteristics of the p-i-p diode were studied with regard to temperature sensor applications. The temperature coefficient of resistance (TCR=-0.05 K{sup -1}) for temperatures above 600 K is about four times larger than the maximal attainable TCR for conventional boron-doped diamond resistors. (orig.)

  5. Improved DC Gun and Insulator Assembly

    Energy Technology Data Exchange (ETDEWEB)

    Neubauer, Michael [Thomas Jefferson National Accelerator Facility (TJNAF), Newport News, VA (United States)

    2015-01-11

    Many user facilities such as synchrotron radiation light sources and free electron lasers rely on DC high voltage photoguns with internal field gradients as high as 10 to 15 MV/m. These high gradients often lead to field emission which poses serious problems for the photocathode used to generate the electron beam and the ceramic insulators used to bias the photocathode at high voltage. Ceramic insulators are difficult to manufacture, require long commissioning times, and have poor reliability, in part because energetic electrons bury themselves in the ceramic causing a buildup of charge and eventual puncture, and also because large diameter ceramics are difficult to braze reliably. The lifetimes of photo cathodes inside high current DC guns exhibiting field emission are limited to less than a hundred hours. Reducing the surface gradients on the metals reduces the field emission, which serves to maintain the required ultrahigh vacuum condition. A novel gun design with gradients around 5 MV/m and operating at 350 kV, a major improvement over existing designs, was proposed that allows for the in-situ replacement of photo cathodes in axially symmetric designs using inverted ceramics. In this project, the existing JLAB CEBAF asymmetric gun design with an inverted ceramic support was modeled and the beam dynamics characterized. An improved structure was designed that reduces the surface gradients and improves the beam optics. To minimize the surface gradients, a number of electrostatic gun designs were studied to determine the optimum configuration of the critical electrodes within the gun structure. Coating experiments were carried out to create a charge dissipative coating for cylindrical ceramics. The phase II proposal, which was not granted, included the design and fabrication of an axially symmetric DC Gun with an inverted ceramic that would operate with less than 5 MV/m at 350 kV and would be designed with an in-situ replaceable photo-cathode.

  6. Characterization of silicon-on-insulator wafers

    Science.gov (United States)

    Park, Ki Hoon

    The silicon-on-insulator (SOI) is attracting more interest as it is being used for an advanced complementary-metal-oxide-semiconductor (CMOS) and a base substrate for novel devices to overcome present obstacles in bulk Si scaling. Furthermore, SOI fabrication technology has improved greatly in recent years and industries produce high quality wafers with high yield. This dissertation investigated SOI material properties with simple, yet accurate methods. The electrical properties of as-grown wafers such as electron and hole mobilities, buried oxide (BOX) charges, interface trap densities, and carrier lifetimes were mainly studied. For this, various electrical measurement techniques were utilized such as pseudo-metal-oxide-semiconductor field-effect-transistor (PseudoMOSFET) static current-voltage (I-V) and transient drain current (I-t), Hall effect, and MOS capacitance-voltage/capacitance-time (C-V/C-t). The electrical characterization, however, mainly depends on the pseudo-MOSFET method, which takes advantage of the intrinsic SOI structure. From the static current-voltage and pulsed measurement, carrier mobilities, lifetimes and interface trap densities were extracted. During the course of this study, a pseudo-MOSFET drain current hysteresis regarding different gate voltage sweeping directions was discovered and the cause was revealed through systematic experiments and simulations. In addition to characterization of normal SOI, strain relaxation of strained silicon-on-insulator (sSOI) was also measured. As sSOI takes advantage of wafer bonding in its fabrication process, the tenacity of bonding between the sSOI and the BOX layer was investigated by means of thermal treatment and high dose energetic gamma-ray irradiation. It was found that the strain did not relax with processes more severe than standard CMOS processes, such as anneals at temperature as high as 1350 degree Celsius.

  7. Detection of insulation flaws and thermal bridges in insulated truck box panels

    OpenAIRE

    Lei, Lei; Bortolin, Alessandro; Bison, Paolo ©; Maldague, X.

    2017-01-01

    This paper focuses on the detection of defects and thermal bridges in insulated truck box panels, utilising infrared thermography. Unlike the traditional way in which passive thermography is applied, this research uses both heating and cooling methods in active thermography configurations. Lamp heating is used as the hot external stimulation, while a compressed air jet is applied as the cold external stimulation. A thermal camera captures the whole process. In addition, numerical simulations ...

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

    International Nuclear Information System (INIS)

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

    2014-01-01

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

  9. Simulation and Experimental Determination of Technological Liquid Molding Parameters of Tubing Basalt Insulation

    Directory of Open Access Journals (Sweden)

    Yu. V. Badanina

    2015-01-01

    Full Text Available The article is dedicated to one of the most important and urgent tasks in mechanical engineering development - the creation of low-density and environmentally-friendly thermoinsulation from available cheap basalt fibers for products to operate at temperatures up to 700°C.One of the most effective applications of such thermo-insulation is to develop and provide highly porous coatings from short basalt fibers by liquid filtration for tubing (T to supply superheated up to 420° C steam under pressure of 35 MPa in the deep layers with severe highviscosity oil. Tubing with the short low-density basalt insulation can be used for a greater depth than the vacuum-insulated tubing, which are also called "thermo-cases", and do not fully meet business needs for long-term reliability of oil vacuum tubes, too large mass per unit length of their design and, as a consequence, the impossibility to use such pipes for deep wells.The aim of the work is to simulate a liquid filtration process of short fibers and determine technological parameters of producing thermal insulation coatings of tubing pipes from basalt fibers and mineral binder shaped as cylinders and cylindrical shells. The paper proposes a mathematical model of free filtration deposition of short fibers from liquid slurry, which describes dynamics of creating thermal insulation products and allows us to determine the rational parameters of their manufacturing process. It shows methods to improve the products quality while forming the thermal insulation by filtration through additional vacuum deposition of a filtrate chamber and the final prepressing of sediment layer, giving dimensions and shape to the final product.The paper defines a prescription hydro mass composition. It shows that to increase the compressive strength of highly fibrous rings and cylindrical shells it is necessary to use based on oxide А12O3 5-7% by weight mineral binder, which fixes basalt fibers in places of their contacts. It

  10. Risk Assessment of Failure of Outdoor High Voltage Polluted Insulators under Combined Stresses Near Shoreline

    Directory of Open Access Journals (Sweden)

    Muhammad Majid Hussain

    2017-10-01

    Full Text Available The aim of this paper is to investigate the various effects of climate conditions on outdoor insulators in coastal areas as a result of saline contamination under acidic and normal cold fog, determining significant electrical and physico-chemical changes on the insulator surface and considering the effect of discharge current, electric field distribution and surface roughness. To replicate similar conditions near the shoreline, experimental investigations have been carried out on insulation materials with the combined application of saline contamination and acidic or normal cold fog. The test samples included silicone rubber (SiR, ethylene propylene diene monomer (EPDM and high-density polyethylene (HDPE, which were used as reference. The materials are of the same composition as those used in real-life outdoor high voltage insulators. All samples were aged separately in an environmental chamber for 150 h for various saline contaminations combined with acidic and normal cold fog, and were generated by means of the adopted experimental setup. This analysis represented conditions similar to those existing near the shoreline exposed to saline and acid spray during winter and early spring. Electric field and discharge current along polymeric samples were examined under acidic and normal cold fog. Fourier transform infrared (FTIR spectroscopy and scanning electron microscopic (SEM were used to probe the physico-chemical changes on the samples surface and investigate the hydrophobicity recovery property after aging tests. Finally, a comparative study was carried out on polymeric samples before and after being exposed to the acidic and normal cold fog based on the results obtained from the experiment. Research data may provide references for the better prediction of surface degradation as well as for the better material coating and design of external insulation.

  11. Thermographic identification of wetted insulation on pipelines in the arctic oilfields

    Science.gov (United States)

    Miles, Jonathan J.; Dahlquist, A. L.; Dash, L. C.

    2006-04-01

    Steel pipes used at Alaskan oil-producing facilities to transport production crude, gas, and injection water between well house and drill site manifold building, and along cross-country lines to and from central processing facilities, must be insulated in order to protect against the severely cold temperatures that are common during the arctic winter. A problem inherent with this system is that the sealed joints between adjacent layers of the outer wrap will over time degrade and can allow water to breach the system and migrate into and through the insulation. The moisture can ultimately interact with the steel pipe and trigger external corrosion which, if left unchecked, can lead to pipe failure and spillage. A New Technology Evaluation Guideline prepared for ConocoPhillips Alaska, Inc. in 2001 is intended to guide the consideration of new technologies for pipeline inspection in a manner that is safer, faster, and more cost-effective than existing techniques. Infrared thermography (IRT) was identified as promising for identification of wetted insulation regions given that it offers the means to scan a large area quickly from a safe distance, and measure the temperature field associated with that area. However, it was also recognized that there are limiting factors associated with an IRT-based approach including instrument sensitivity, cost, portability, functionality in hostile (arctic) environments, and training required for proper interpretation of data. A methodology was developed and tested in the field that provides a technique to conduct large-scale screening for wetted regions along insulated pipelines. The results of predictive modeling analysis and testing demonstrate the feasibility under certain condition of identifying wetted insulation areas. The results of the study and recommendations for implementation are described.

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

    International Nuclear Information System (INIS)

    Guo Jun-Ji; Liao Wen-Hu

    2014-01-01

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

  13. Study of Hygrothermal Processes in External Walls with Internal Insulation

    Directory of Open Access Journals (Sweden)

    Biseniece Edite

    2018-03-01

    Full Text Available Being an important contributor to the final energy consumption, historic buildings built before 1945 have high specific heating energy consumption compared to current energy standards and norms. However, they often cannot be insulated from the outside due to their heritage and culture value. Internal insulation is an alternative. However internal insulation faces challenges related to hygrothermal behaviour leading to mold growth, freezing, deterioration and other risks. The goal of this research is to link hygrothermal simulation results with experimental results for internally insulated historic brick masonry to assess correlation between simulated and measured data as well as the most influential parameters. The study is carried out by both a mathematical simulation tool and laboratory tests of historic masonry with internal insulation with four insulation materials (mineral wool, EPS, wood fiber and granulated aerogel in a cold climate (average 4000 heating degree days. We found disparity between measured and simulated hygrothermal performance of studied constructions due to differences in material parameters and initial conditions of materials. The latter plays a more important role than material parameters. Under a steady state of conditions, the condensate tolerating system varies between 72.7 % and 80.5 % relative humidity, but in condensate limiting systems relative humidity variates between 73.3 % and 82.3 %. The temperature between the masonry wall and all insulation materials has stabilized on average at +10 °C. Mold corresponding to Mold index 3 was discovered on wood fiber mat.

  14. Study of Hygrothermal Processes in External Walls with Internal Insulation

    Science.gov (United States)

    Biseniece, Edite; Freimanis, Ritvars; Purvins, Reinis; Gravelsins, Armands; Pumpurs, Aivars; Blumberga, Andra

    2018-03-01

    Being an important contributor to the final energy consumption, historic buildings built before 1945 have high specific heating energy consumption compared to current energy standards and norms. However, they often cannot be insulated from the outside due to their heritage and culture value. Internal insulation is an alternative. However internal insulation faces challenges related to hygrothermal behaviour leading to mold growth, freezing, deterioration and other risks. The goal of this research is to link hygrothermal simulation results with experimental results for internally insulated historic brick masonry to assess correlation between simulated and measured data as well as the most influential parameters. The study is carried out by both a mathematical simulation tool and laboratory tests of historic masonry with internal insulation with four insulation materials (mineral wool, EPS, wood fiber and granulated aerogel) in a cold climate (average 4000 heating degree days). We found disparity between measured and simulated hygrothermal performance of studied constructions due to differences in material parameters and initial conditions of materials. The latter plays a more important role than material parameters. Under a steady state of conditions, the condensate tolerating system varies between 72.7 % and 80.5 % relative humidity, but in condensate limiting systems relative humidity variates between 73.3 % and 82.3 %. The temperature between the masonry wall and all insulation materials has stabilized on average at +10 °C. Mold corresponding to Mold index 3 was discovered on wood fiber mat.

  15. Insulated Wire Fed Floating Monopole Antenna for Coastal Monitoring

    Directory of Open Access Journals (Sweden)

    Z. M. Loni

    2018-04-01

    Full Text Available A thin, flexible, insulated wire submerged in seawater forms a coaxial cable which has attenuation at ultra-high frequency (UHF dependent on the operating frequency, the diameter of the insulating material and the diameter of the inner conductor. An extension of the insulated wire above the surface through a spherical float forms a monopole antenna. Attenuation through the wire depends on the conductivity and temperature of seawater. This paper reports the effect of electromagnetic (EM wave propagation at 433 MHz through insulated wires with different radii of the insulating material and inner conductor. The attenuation was calculated and measured in the range of 32-47 dB/m. The propagation from the monopole antenna to a fixed shore based receiver was measured to be approximately equal to 1 dB/m. The propagation measurements were compared with a shielded coaxial cable. Results show that the propagation range depends on the ratio of the insulation radius to conductor radius for insulated wire, however, a shielded coaxial cable showed no significant attenuation. The technique has applications in coastal wireless sensor networks where the water depth changes continually due to tide and wave motion.

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

    International Nuclear Information System (INIS)

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

    1995-01-01

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

  17. Insulation coordination workstation for AC and DC substations

    International Nuclear Information System (INIS)

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

    1990-01-01

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

  18. Parametric Investigation of Optimum Thermal Insulation Thickness for External Walls

    Directory of Open Access Journals (Sweden)

    Omer Kaynakli

    2011-06-01

    Full Text Available Numerous studies have estimated the optimum thickness of thermal insulation materials used in building walls for different climate conditions. The economic parameters (inflation rate, discount rate, lifetime and energy costs, the heating/cooling loads of the building, the wall structure and the properties of the insulation material all affect the optimum insulation thickness. This study focused on the investigation of these parameters that affect the optimum thermal insulation thickness for building walls. To determine the optimum thickness and payback period, an economic model based on life-cycle cost analysis was used. As a result, the optimum thermal insulation thickness increased with increasing the heating and cooling energy requirements, the lifetime of the building, the inflation rate, energy costs and thermal conductivity of insulation. However, the thickness decreased with increasing the discount rate, the insulation material cost, the total wall resistance, the coefficient of performance (COP of the cooling system and the solar radiation incident on a wall. In addition, the effects of these parameters on the total life-cycle cost, payback periods and energy savings were also investigated.

  19. 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.

  20. Comparative Investigation on the Performance of Modified System Poles and Traditional System Poles Obtained from PDC Data for Diagnosing the Ageing Condition of Transformer Polymer Insulation Materials

    Directory of Open Access Journals (Sweden)

    Jiefeng Liu

    2018-02-01

    Full Text Available The life expectancy of a transformer is largely depended on the service life of transformer polymer insulation materials. Nowadays, several papers have reported that the traditional system poles obtained from polarization and depolarization current (PDC data can be used to assess the condition of transformer insulation systems. However, the traditional system poles technique only provides limited ageing information for transformer polymer insulation. In this paper, the modified system poles obtained from PDC data are proposed to assess the ageing condition of transformer polymer insulation. The aim of the work is to focus on reporting a comparative investigation on the performance of modified system poles and traditional system poles for assessing the ageing condition of a transformer polymer insulation system. In the present work, a series of experiments have been performed under controlled laboratory conditions. The PDC measurement data, degree of polymerization (DP and moisture content of the oil-immersed polymer pressboard specimens were carefully monitored. It is observed that, compared to the relationships between traditional system poles and DP values, there are better correlations between the modified system poles and DP values, because the modified system poles can obtain much more ageing information on transformer polymer insulation. Therefore, the modified system poles proposed in the paper are more suitable for the diagnosis of the ageing condition of transformer polymer insulation.