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Sample records for adapter insulator ring

  1. Gas insulated transmission line having tapered particle trapping ring

    DOEpatents

    Cookson, Alan H.

    1982-01-01

    A gas-insulated transmission line includes an outer sheath, an inner conductor, insulating supports and an insulating gas. A particle-trapping ring is secured to each insulating support, and it is comprised of a central portion and two tapered end portions. The ends of the particle trapping ring have a smaller diameter than the central portion of the ring, so as to enable the use of the particle trapping ring in a curved transmission line.

  2. Persistent Hall voltages across thin planar charged quantum rings on the surface of a topological insulator

    NASA Astrophysics Data System (ADS)

    Durganandini, P.

    2015-03-01

    We consider thin planar charged quantum rings on the surface of a three dimensional topological insulator coated with a thin ferromagnetic layer. We show theoretically, that when the ring is threaded by a magnetic field, then, due to the Aharanov-Bohm effect, there are not only the well known circulating persistent currents in the ring but also oscillating persistent Hall voltages across the thin ring. Such oscillating persistent Hall voltages arise due to the topological magneto-electric effect associated with the axion electrodynamics exhibited by the surface electronic states of the three dimensional topological insulator when time reversal symmetry is broken. We further generalize to the case of dipole currents and show that analogous Hall dipole voltages arise. We also discuss the robustness of the effect and suggest possible experimental realizations in quantum rings made of semiconductor heterostructures. Such experiments could also provide new ways of observing the predicted topological magneto-electric effect in three dimensional topological insulators with time reversal symmetry breaking. I thank BCUD, Pune University, Pune for financial support through research grant.

  3. Dual wavelength demultiplexer based on metal-insulator-metal plasmonic circular ring resonators

    NASA Astrophysics Data System (ADS)

    Rakhshani, Mohammad Reza; Mansouri-Birjandi, Mohammad Ali

    2016-06-01

    In this paper, we investigated a plasmonic demultiplexer structure based on Metal-Insulator-Metal (MIM) waveguides and circular ring resonators. In order to achieve the structure of demultiplexer, two improved ring resonators have been used, which input and outputs MIM waveguides coupled by the ring resonators. To improve the transmission efficiency, a reflector was introduced at the right end of the input and output waveguides. By substituting the ring core with dielectric, the possibility of tuning the resonance wavelength of the proposed structure is illustrated, and the effect of various parameters such as radius and refractive index in transmission efficiency is studied in detail. This is useful for the design of integrated circuits in which it is not possible to extend the dimension of the ring resonator to attain a longer resonance wavelength. Transmission efficiency and quality factor of the single ring are 84% and 110, respectively. The simulation results using finite difference time domain method shows that in the proposed demultiplexer, which is composed of two rings with different core refractive indexes, the average power efficiency, bandwidth for each output channel, and the mean value of crosstalk are estimated 80%, 17 nm, and -26.95 dB, respectively. It is revealed that the significant features of the device are high transmission efficiency, low crosstalk, high-quality factor, and tunability for desired wavelengths. Therefore, the proposed structure has the potential to be applied in plasmonic integrated circuits.

  4. A Refractive Index Sensor Based on a Metal-Insulator-Metal Waveguide-Coupled Ring Resonator

    PubMed Central

    Yan, Shu-Bin; Luo, Liang; Xue, Chen-Yang; Zhang, Zhi-Dong

    2015-01-01

    A refractive index sensor composed of two straight metal-insulator-metal waveguides and a ring resonator is presented. One end of each straight waveguide is sealed and the other end acts as port. The transmission spectrum and magnetic field distribution of this sensor structure are simulated using finite-difference time-domain method (FDTD). The results show that an asymmetric line shape is observed in the transmission spectrum, and that the transmission spectrum shows a filter-like behavior. The quality factor and sensitivity are taken to characterize its sensing performance and filter properties. How structural parameters affect the sensing performance and filter properties is also studied. PMID:26610491

  5. Solitons, charge fractionization, and the emergence of topological insulators in graphene rings

    NASA Astrophysics Data System (ADS)

    Yannouleas, Constantine; Romanovsky, Igor; Landman, Uzi

    2014-03-01

    The doubly-connected polygonal geometry of planar graphene rings is found to bring forth topological configurations for accessing nontrivial relativistic quantum field (RQF) theory models that carry beyond the constant-mass Dirac-fermion theory. These include generation of sign-alternating masses, solitonic excitations, and charge fractionization. The work integrates a RQF Lagrangian formulation with numerical tight-binding Aharonov-Bohm electronic spectra and the generalized position-dependent-mass Dirac equation. In contrast to armchair graphene rings (aGRGs) with pure metallic arms,[2] certain classes of aGRGs with semiconducting arms, as well as with mixed metallic-semiconducting ones, are shown to exhibit properties of one-dimensional nontrivial topological insulators. This further reveals an alternative direction for realizing a graphene-based nontrivial topological insulator through the manipulation of the honeycomb lattice geometry, without a spin-orbit contribution. Supported by the U.S. D.O.E. (FG05-86ER-45234).

  6. The insulator protein Suppressor of Hairy wing is required for proper ring canal development during oogenesis in Drosophila.

    PubMed

    Hsu, Shih-Jui; Plata, Maria P; Ernest, Ben; Asgarifar, Saghi; Labrador, Mariano

    2015-07-01

    Chromatin insulators orchestrate gene transcription during embryo development and cell differentiation by stabilizing interactions between distant genomic sites. Mutations in genes encoding insulator proteins are generally lethal, making in vivo functional analyses of insulator proteins difficult. In Drosophila, however, mutations in the gene encoding the Suppressor of Hairy wing insulator protein [Su(Hw)] are viable and female sterile, providing an opportunity to study insulator function during oocyte development. Whereas previous reports suggest that the function of Su(Hw) in oogenesis is independent of its insulator activity, many aspects of the role of Su(Hw) in Drosophila oogenesis remain unexplored. Here we show that mutations in su(Hw) result in smaller ring canal lumens and smaller outer ring diameters, which likely obstruct molecular and vesicle passage from nurse cells to the oocyte. Fluorescence microscopy reveals that lack of Su(Hw) leads to excess accumulation of Kelch (Kel) and Filament-actin (F-actin) proteins in the ring canal structures of developing egg chambers. Furthermore, we found that misexpression of the Src oncogene at 64B (Src64B) may cause ring canal development defects as microarray analysis and real-time RT-PCR revealed there is a three fold decrease in Src64B expression in su(Hw) mutant ovaries. Restoration of Src64B expression in su(Hw) mutant female germ cells rescued the ring phenotype but did not restore fertility. We conclude that loss of su(Hw) affects expression of many oogenesis related genes and down-regulates Src64B, resulting in ring canal defects potentially contributing to obstruction of molecular flow and an eventual failure of egg chamber organization.

  7. Topological insulator behavior of WS2 monolayer with square-octagon ring structure

    NASA Astrophysics Data System (ADS)

    Kumar, Ashok; Pandey, Ravindra; Ahluwalia, P. K.; Tankeshwar, K.

    2016-05-01

    We report electronic behavior of an allotrope of monolayer WS2 with a square octagon ring structure, refereed to as (so-WS2) within state-of-the-art density functional theory (DFT) calculations. The WS2 monolayer shows semi-metallic characteristics with Dirac-cone like features around D. Unlike p-orbital's Dirac-cone in graphene, the Dirac-cone in the so-WS2 monolayer originates from the d-electrons of the W atom in the lattice. Most interestingly, the spin-orbit interaction associated with d-electrons induce a finite band-gap that results into the metal-semiconductor transition and topological insulator-like behavior in the so-WS2 monolayer. These characteristics suggest the so-WS2 monolayer to be a promising candidate for the next-generation electronic and spintronics devices.

  8. Air-mode photonic crystal ring resonator on silicon-on-insulator.

    PubMed

    Gao, Ge; Zhang, Yong; Zhang, He; Wang, Yi; Huang, Qingzhong; Xia, Jinsong

    2016-01-01

    In this report, we propose and demonstrate an air-mode photonic crystal ring resonator (PhCRR) on silicon-on-insulator platform. Air mode is utilized to confine the optical field into photonic crystal (PhC) air holes, which is confirmed by the three-dimensional finite-difference time-domain simulation. PhCRR structure is employed to enhance the light-matter interaction through combining the whispering-gallery mode resonance of ring resonator with the slow-light effect in PhC waveguide. In the simulated and measured transmission spectra of air-mode PhCRR, nonuniform free spectral ranges are observed near the Brillouin zone edge of PhC, indicating the presence of the slow-light effect. A maximum group index of 27.3 and a highest quality factor of 14600 are experimentally obtained near the band edge. Benefiting from the strong optical confinement in the PhC holes and enhanced light-matter interaction in the resonator, the demonstrated air-mode PhCRR is expected to have potential applications in refractive index sensing, on-chip light emitting and nonlinear optics by integration with functional materials. PMID:26818430

  9. Air-mode photonic crystal ring resonator on silicon-on-insulator

    NASA Astrophysics Data System (ADS)

    Gao, Ge; Zhang, Yong; Zhang, He; Wang, Yi; Huang, Qingzhong; Xia, Jinsong

    2016-01-01

    In this report, we propose and demonstrate an air-mode photonic crystal ring resonator (PhCRR) on silicon-on-insulator platform. Air mode is utilized to confine the optical field into photonic crystal (PhC) air holes, which is confirmed by the three-dimensional finite-difference time-domain simulation. PhCRR structure is employed to enhance the light-matter interaction through combining the whispering-gallery mode resonance of ring resonator with the slow-light effect in PhC waveguide. In the simulated and measured transmission spectra of air-mode PhCRR, nonuniform free spectral ranges are observed near the Brillouin zone edge of PhC, indicating the presence of the slow-light effect. A maximum group index of 27.3 and a highest quality factor of 14600 are experimentally obtained near the band edge. Benefiting from the strong optical confinement in the PhC holes and enhanced light-matter interaction in the resonator, the demonstrated air-mode PhCRR is expected to have potential applications in refractive index sensing, on-chip light emitting and nonlinear optics by integration with functional materials.

  10. Air-mode photonic crystal ring resonator on silicon-on-insulator.

    PubMed

    Gao, Ge; Zhang, Yong; Zhang, He; Wang, Yi; Huang, Qingzhong; Xia, Jinsong

    2016-01-28

    In this report, we propose and demonstrate an air-mode photonic crystal ring resonator (PhCRR) on silicon-on-insulator platform. Air mode is utilized to confine the optical field into photonic crystal (PhC) air holes, which is confirmed by the three-dimensional finite-difference time-domain simulation. PhCRR structure is employed to enhance the light-matter interaction through combining the whispering-gallery mode resonance of ring resonator with the slow-light effect in PhC waveguide. In the simulated and measured transmission spectra of air-mode PhCRR, nonuniform free spectral ranges are observed near the Brillouin zone edge of PhC, indicating the presence of the slow-light effect. A maximum group index of 27.3 and a highest quality factor of 14600 are experimentally obtained near the band edge. Benefiting from the strong optical confinement in the PhC holes and enhanced light-matter interaction in the resonator, the demonstrated air-mode PhCRR is expected to have potential applications in refractive index sensing, on-chip light emitting and nonlinear optics by integration with functional materials.

  11. Air-mode photonic crystal ring resonator on silicon-on-insulator

    PubMed Central

    Gao, Ge; Zhang, Yong; Zhang, He; Wang, Yi; Huang, Qingzhong; Xia, Jinsong

    2016-01-01

    In this report, we propose and demonstrate an air-mode photonic crystal ring resonator (PhCRR) on silicon-on-insulator platform. Air mode is utilized to confine the optical field into photonic crystal (PhC) air holes, which is confirmed by the three-dimensional finite-difference time-domain simulation. PhCRR structure is employed to enhance the light-matter interaction through combining the whispering-gallery mode resonance of ring resonator with the slow-light effect in PhC waveguide. In the simulated and measured transmission spectra of air-mode PhCRR, nonuniform free spectral ranges are observed near the Brillouin zone edge of PhC, indicating the presence of the slow-light effect. A maximum group index of 27.3 and a highest quality factor of 14600 are experimentally obtained near the band edge. Benefiting from the strong optical confinement in the PhC holes and enhanced light-matter interaction in the resonator, the demonstrated air-mode PhCRR is expected to have potential applications in refractive index sensing, on-chip light emitting and nonlinear optics by integration with functional materials. PMID:26818430

  12. Insulation.

    ERIC Educational Resources Information Center

    Rhea, Dennis

    This instructional unit is one of 10 developed by students on various energy-related areas that deals specifically with insulation. Its objective is for the student to be able to determine insulation needs of new or existing structures, select type to use, use installation techniques, calculate costs, and apply safety factors. Some topics covered…

  13. Vertical optical ring resonators fully integrated with nanophotonic waveguides on silicon-on-insulator substrates.

    PubMed

    Madani, Abbas; Kleinert, Moritz; Stolarek, David; Zimmermann, Lars; Ma, Libo; Schmidt, Oliver G

    2015-08-15

    We demonstrate full integration of vertical optical ring resonators with silicon nanophotonic waveguides on silicon-on-insulator substrates to accomplish a significant step toward 3D photonic integration. The on-chip integration is realized by rolling up 2D differentially strained TiO(2) nanomembranes into 3D microtube cavities on a nanophotonic microchip. The integration configuration allows for out-of-plane optical coupling between the in-plane nanowaveguides and the vertical microtube cavities as a compact and mechanically stable optical unit, which could enable refined vertical light transfer in 3D stacks of multiple photonic layers. In this vertical transmission scheme, resonant filtering of optical signals at telecommunication wavelengths is demonstrated based on subwavelength thick-walled microcavities. Moreover, an array of microtube cavities is prepared, and each microtube cavity is integrated with multiple waveguides, which opens up interesting perspectives toward parallel and multi-routing through a single-cavity device as well as high-throughput optofluidic sensing schemes.

  14. Floquet-Weyl and Floquet-topological-insulator phases in a stacked two-dimensional ring-network lattice

    NASA Astrophysics Data System (ADS)

    Ochiai, Tetsuyuki

    2016-10-01

    We show the presence of Floquet-Weyl and Floquet-topological-insulator phases in a stacked two-dimensional ring-network lattice. The Weyl points in the three-dimensional Brillouin zone and Fermi-arc surface states are clearly demonstrated in the quasienergy spectrum of the system in the Floquet-Weyl phase. In addition, chiral surface states coexist in this phase. The Floquet-topological-insulator phase is characterized by the winding number of two in the reflection matrices of the semi-infinite system and resulting two gapless surface states in the quasienergy gap of the bulk. The phase diagram of the system is derived in the two-parameter space of hopping S-matrices among the rings. We also discuss a possible optical realization of the system together with the introduction of synthetic gauge fields.

  15. Floquet-Weyl and Floquet-topological-insulator phases in a stacked two-dimensional ring-network lattice.

    PubMed

    Ochiai, Tetsuyuki

    2016-10-26

    We show the presence of Floquet-Weyl and Floquet-topological-insulator phases in a stacked two-dimensional ring-network lattice. The Weyl points in the three-dimensional Brillouin zone and Fermi-arc surface states are clearly demonstrated in the quasienergy spectrum of the system in the Floquet-Weyl phase. In addition, chiral surface states coexist in this phase. The Floquet-topological-insulator phase is characterized by the winding number of two in the reflection matrices of the semi-infinite system and resulting two gapless surface states in the quasienergy gap of the bulk. The phase diagram of the system is derived in the two-parameter space of hopping S-matrices among the rings. We also discuss a possible optical realization of the system together with the introduction of synthetic gauge fields. PMID:27589340

  16. Beyond the constant-mass Dirac physics: Solitons, charge fractionization, and the emergence of topological insulators in graphene rings

    NASA Astrophysics Data System (ADS)

    Yannouleas, Constantine; Romanovsky, Igor; Landman, Uzi

    2014-01-01

    The doubly connected polygonal geometry of planar graphene rings is found to bring forth topological configurations for accessing nontrivial relativistic quantum field (RQF) theory models that carry beyond the constant-mass Dirac-fermion theory. These include the generation of sign-alternating masses, solitonic excitations, and charge fractionization. The work integrates a RQF Lagrangian formulation with numerical tight-binding Aharonov-Bohm electronic spectra and the generalized position-dependent-mass Dirac equation. In contrast to armchair graphene rings (aGRGs) with pure metallic arms, certain classes of aGRGs with semiconducting arms, as well as with mixed metallic-semiconducting ones, are shown to exhibit properties of one-dimensional nontrivial topological insulators. This further reveals an alternative direction for realizing a graphene-based nontrivial topological insulator through the manipulation of the honeycomb lattice geometry, without a spin-orbit contribution.

  17. Experimental demonstration of coupled-resonator-induced-transparency in silicon-on-insulator based ring-bus-ring geometry.

    PubMed

    Darmawan, S; Tobing, L Y M; Zhang, D H

    2011-08-29

    We experimentally demonstrate coupled-resonator-induced-transparency (CRIT) phenomenon in ring-bus-ring (RBR) geometry synergistically integrated with Mach-Zehnder interferometer (MZI). The RBR consists of two detuned resonators indirectly coupled through a center bus waveguide. The transparency is obtained by increasing the light intercavity interaction through tailoring the RBR phase response while ensuring balanced MZI operation. In this work, a CRIT resonance with a quality factor of ~18,000 is demonstrated with cavity size detuning of ~0.035% and power coupling of ~60%, which are in good agreement with the theory.

  18. Narrow line-width single-longitudinal-mode fiber laser using silicon-on-insulator based micro-ring-resonator

    NASA Astrophysics Data System (ADS)

    Liu, Yang; Hsu, Yung; Hsu, Chin-Wei; Yang, Ling-Gang; Chow, Chi-Wai; Yeh, Chien-Hung; Lai, Yin-Chieh; Tsang, Hon-Ki

    2016-02-01

    In this work, we propose and demonstrate a stable single-longitudinal-mode (SLM) fiber laser with narrow line-width by using an integrated silicon-on-insulator micro-ring resonator (SOI MRR) and two subsidiary fiber rings for the first time, to the best of our knowledge. The laser is tunable over the wavelength range from 1546 to 1570 nm, with only step tuning of 2 nm steps. A maximum 49 dB side mode suppression ratio (SMSR) can be achieved. The compact SOI MRR provides a large free-spectral-range (FSR), while the subsidiary rings provide Vernier effect producing a single lasing mode. The FSR of the SOI MRR can be very large and controllable (since it is easy to fabricate small SOI MRR when compared with making small fiber-rings) using the complementary-metal-oxide-semiconductor (CMOS) compactable SOI fabrication processes. In our proposed laser, the measured single sideband (SSB) spectrum shows that the densely spaced longitudinal modes can be significantly suppressed to achieve SLM. The laser linewidth is only 3.5 kHz measured by using the self-heterodyne method. 30 min stability evaluation in terms of lasing wavelength and optical power is performed; showing the optical wavelength and power are both very stable, with fluctuations of only 0.02 nm and 0.8 dB, respectively.

  19. Experimental demonstration of ultracompact air hole photonic crystal ring resonator fabricated on silicon-on-insulator wafer.

    PubMed

    Ren, Xiaoyuan; Feng, Lishuang; Lin, Zhili; Feng, Junbo

    2013-05-01

    A photonic crystal ring resonator (PCRR) of air hole arrays is fabricated on a silicon-on-insulator wafer by using electron-beam lithography and inductively coupled plasma etching. The designed PCRR is modeled and its performance is simulated by the two-dimensional finite difference time domain method. The simulation results show that the PCRR has two resonant wavelengths, 1598 and 1606 nm, and their corresponding quality factors are 3994 and 4015, respectively. A sample of the PCRR structure is fabricated and tested by the established experimental setup. Compared with the simulation results, the experimental resonant wavelengths drift to some extent and the quality factors are reduced by about one order of magnitude. The fabrication error and irregularity are the main reasons for the above results, which can be further reduced by improving the process technology. In addition, one more resonant wavelength emerged for the PCRR sample, which can be attributed to the change of the coupling strength. PMID:23632503

  20. High voltage variable diameter insulator

    DOEpatents

    Vanacek, D.L.; Pike, C.D.

    1982-07-13

    A high voltage feedthrough assembly having a tubular insulator extending between the ground plane ring and the high voltage ring. The insulator is made of Pyrex and decreases in diameter from the ground plane ring to the high voltage ring, producing equipotential lines almost perpendicular to the wall of the insulator to optimize the voltage-holding capability of the feedthrough assembly.

  1. Speed tracking and synchronization of multiple motors using ring coupling control and adaptive sliding mode control.

    PubMed

    Li, Le-Bao; Sun, Ling-Ling; Zhang, Sheng-Zhou; Yang, Qing-Quan

    2015-09-01

    A new control approach for speed tracking and synchronization of multiple motors is developed, by incorporating an adaptive sliding mode control (ASMC) technique into a ring coupling synchronization control structure. This control approach can stabilize speed tracking of each motor and synchronize its motion with other motors' motion so that speed tracking errors and synchronization errors converge to zero. Moreover, an adaptive law is exploited to estimate the unknown bound of uncertainty, which is obtained in the sense of Lyapunov stability theorem to minimize the control effort and attenuate chattering. Performance comparisons with parallel control, relative coupling control and conventional PI control are investigated on a four-motor synchronization control system. Extensive simulation results show the effectiveness of the proposed control scheme.

  2. High voltage variable diameter insulator

    DOEpatents

    Vanecek, David L.; Pike, Chester D.

    1984-01-01

    A high voltage feedthrough assembly (10) having a tubular insulator (15) extending between the ground plane ring (16) and the high voltage ring (30). The insulator (15) is made of Pyrex and decreases in diameter from the ground plane ring (16) to the high voltage ring (30), producing equipotential lines almost perpendicular to the wall (27) of the insulator (15) to optimize the voltage-holding capability of the feedthrough assembly (10).

  3. Orbital disc insulator for SF.sub.6 gas-insulated bus

    DOEpatents

    Bacvarov, Dosio C.; Gomarac, Nicholas G.

    1977-01-01

    An insulator for supporting a high voltage conductor within a gas-filled grounded housing consists of radially spaced insulation rings fitted to the exterior of the bus and the interior of the grounded housing respectively, and the spaced rings are connected by trefoil type rings which are integrally formed with the spaced insulation rings.

  4. The c-ring stoichiometry of ATP synthase is adapted to cell physiological requirements of alkaliphilic Bacillus pseudofirmus OF4.

    PubMed

    Preiss, Laura; Klyszejko, Adriana L; Hicks, David B; Liu, Jun; Fackelmayer, Oliver J; Yildiz, Özkan; Krulwich, Terry A; Meier, Thomas

    2013-05-01

    The c-rings of ATP synthases consist of individual c-subunits, all of which harbor a conserved motif of repetitive glycine residues (GxGxGxG) important for tight transmembrane α-helix packing. The c-ring stoichiometry determines the number of ions transferred during enzyme operation and has a direct impact on the ion-to-ATP ratio, a cornerstone parameter of cell bioenergetics. In the extreme alkaliphile Bacillus pseudofirmus OF4, the glycine motif is replaced by AxAxAxA. We performed a structural study on two mutants with alanine-to-glycine changes using atomic force microscopy and X-ray crystallography, and found that mutants form smaller c12 rings compared with the WT c13. The molar growth yields of B. pseudofirmus OF4 cells on malate further revealed that the c12 mutants have a considerably reduced capacity to grow on limiting malate at high pH. Our results demonstrate that the mutant ATP synthases with either c12 or c13 can support ATP synthesis, and also underscore the critical importance of an alanine motif with c13 ring stoichiometry for optimal growth at pH >10. The data indicate a direct connection between the precisely adapted ATP synthase c-ring stoichiometry and its ion-to-ATP ratio on cell physiology, and also demonstrate the bioenergetic challenges and evolutionary adaptation strategies of extremophiles.

  5. GaInAsP/silicon-on-insulator hybrid laser with ring-resonator-type reflector fabricated by N2 plasma-activated bonding

    NASA Astrophysics Data System (ADS)

    Hayashi, Yusuke; Suzuki, Junichi; Inoue, Satoshi; Tanvir Hasan, Shovon Muhammad; Kuno, Yuki; Itoh, Kazuto; Amemiya, Tomohiro; Nishiyama, Nobuhiko; Arai, Shigehisa

    2016-08-01

    III-V/Si hybrid integration with direct bonding is an attractive method of realizing an electrophotonic convergence router with a small size and a low power consumption. Plasma-activated bonding (PAB) is an effective approach for reducing thermal stress during the bonding process because PAB achieves a high bonding strength with low-temperature annealing. This time, the fabrication of a GaInAsP/silicon-on-insulator (SOI) hybrid laser with Si ring-resonator-type reflectors was demonstrated by N2 PAB. By measuring the lasing spectra, we confirmed the reflective characteristics resulting from the cascaded Si ring resonators. We also investigated kink characteristics, which occur around the threshold current, of the current-light output (I-L) characteristics, and successfully approximated the kink characteristics by considering saturable absorption occurring at the III-V/Si taper tip. The taper structure was investigated in terms of a passive device as well as an active device, and a structure for eliminating saturable absorption was proposed.

  6. GaInAsP/silicon-on-insulator hybrid laser with ring-resonator-type reflector fabricated by N2 plasma-activated bonding

    NASA Astrophysics Data System (ADS)

    Hayashi, Yusuke; Suzuki, Junichi; Inoue, Satoshi; Tanvir Hasan, Shovon Muhammad; Kuno, Yuki; Itoh, Kazuto; Amemiya, Tomohiro; Nishiyama, Nobuhiko; Arai, Shigehisa

    2016-08-01

    III–V/Si hybrid integration with direct bonding is an attractive method of realizing an electrophotonic convergence router with a small size and a low power consumption. Plasma-activated bonding (PAB) is an effective approach for reducing thermal stress during the bonding process because PAB achieves a high bonding strength with low-temperature annealing. This time, the fabrication of a GaInAsP/silicon-on-insulator (SOI) hybrid laser with Si ring-resonator-type reflectors was demonstrated by N2 PAB. By measuring the lasing spectra, we confirmed the reflective characteristics resulting from the cascaded Si ring resonators. We also investigated kink characteristics, which occur around the threshold current, of the current–light output (I–L) characteristics, and successfully approximated the kink characteristics by considering saturable absorption occurring at the III–V/Si taper tip. The taper structure was investigated in terms of a passive device as well as an active device, and a structure for eliminating saturable absorption was proposed.

  7. Adaptive center determination for effective suppression of ring artifacts in tomography images

    SciTech Connect

    Jha, D. Sørensen, H. O. Dobberschütz, S.; Stipp, S. L. S.; Feidenhans'l, R.

    2014-10-06

    Ring artifacts on tomogram slices hinder image interpretation. They are caused by minor variation in the response from individual elements in a two dimensional (2D) X-ray detector. Polar space decreases the suppression complexity by transforming the rings on the tomogram slice to linear stripes. However, it requires that the center of rings lie at the origin of polar transformation. If this is not the case, all methods employing polar space become ineffective. We developed a method based on Gaussian localization of the ring center in Hough parameter space to assign the origin for the polar transformation. Thus, obtained linear stripes can be effectively suppressed by already existing methods. This effectively suppresses ring artifacts in the data from a variety of experimental setups, sample types and also handles tomograms that are previously cropped. This approach functions automatically, avoids the need for assumptions and preserves fine details, all critical for synchrotron based nanometer resolution tomography.

  8. A mutation in NLA, which encodes a RING-type ubiquitin ligase, disrupts the adaptability of Arabidopsis to nitrogen limitation.

    PubMed

    Peng, Mingsheng; Hannam, Carol; Gu, Honglan; Bi, Yong-Mei; Rothstein, Steven J

    2007-04-01

    Abundant nitrogen is required for the optimal growth and development of plants, while numerous biotic and abiotic factors that consume soil nitrogen frequently create a nitrogen limitation growth condition. To cope with this, plants have evolved a suite of adaptive responses to nitrogen limitation. However, the molecular mechanism governing the adaptability of plants to nitrogen limitation is totally unknown because no reported mutant defines this trait. Here we isolated an Arabidopsis mutant, nla (nitrogen limitation adaptation), and identified the NLA gene as an essential component in this molecular mechanism. Supplied with insufficient inorganic nitrogen (nitrate or ammonium), the nla mutant failed to develop the essential adaptive responses to nitrogen limitation, but senesced much earlier and more rapidly than did the wild type. Under other stress conditions including low phosphorus nutrient, drought and high temperature, the nla mutant did not show this early senescence phenotype, but closely resembled the wild type in growth and development. Map-based cloning of NLA revealed that this gene encodes a RING-type ubiquitin ligase, and nla is a deletion mutation which does not code for the RING domain in the NLA protein. The NLA protein is localized to the nuclear speckles, where this protein interacts with the Arabidopsis ubiquitin conjugase 8 (AtUBC8). In the nla mutant, the deletion of the RING domain from NLA altered its subcellular localization, disrupted the interaction between NLA and AtUBC8 and caused the early senescence phenotype induced by low inorganic nitrogen. All the results indicate that NLA is a positive regulator for the development of the adaptability of Arabidopsis to nitrogen limitation. PMID:17355433

  9. Proposal of Prediction Methods for Compression Set of EP-Rubber O-Rings for Gas Insulated Switchgear

    NASA Astrophysics Data System (ADS)

    Matsuda, Akihiro; Inamine, Morikatsu; Teramoto, Tokuo; Mizutani, Yoshinobu; Goshima, Hisashi; Shinkai, Hiroyuki

    In this paper, a numerical analysis of thermo-mechanical viscoelastic material was investigated to predict the compression set of EP-rubber O-rings for substation facilities. Relaxation times for viscous characteristics of this model were calculated by the Arrhenius equation and temperature of rubber. Furthermore, biaxial loading tests by loading test machine and the stress-relaxation tests in the thermal chamber were conducted to evaluate the mechanical and thermal characteristics and effect of temperature on the stress relaxation to confirm the applicability of the simulation code. From the simulated results, the developed code shows enough accuracy to predict the stress reduction of natural rubber parts under the long-term compression.

  10. The genetic basis of color-related local adaptation in a ring-like colonization around the Mediterranean.

    PubMed

    Burri, Reto; Antoniazza, Sylvain; Gaigher, Arnaud; Ducrest, Anne-Lyse; Simon, Céline; Fumagalli, Luca; Goudet, Jérôme; Roulin, Alexandre

    2016-01-01

    Uncovering the genetic basis of phenotypic variation and the population history under which it established is key to understand the trajectories along which local adaptation evolves. Here, we investigated the genetic basis and evolutionary history of a clinal plumage color polymorphism in European barn owls (Tyto alba). Our results suggest that barn owls colonized the Western Palearctic in a ring-like manner around the Mediterranean and meet in secondary contact in Greece. Rufous coloration appears to be linked to a recently evolved nonsynonymous-derived variant of the melanocortin 1 receptor (MC1R) gene, which according to quantitative genetic analyses evolved under local adaptation during or following the colonization of Central Europe. Admixture patterns and linkage disequilibrium between the neutral genetic background and color found exclusively within the secondary contact zone suggest limited introgression at secondary contact. These results from a system reminiscent of ring species provide a striking example of how local adaptation can evolve from derived genetic variation. PMID:26773815

  11. Active noise control using noise source having adaptive resonant frequency tuning through variable ring loading

    NASA Technical Reports Server (NTRS)

    Pla, Frederic G. (Inventor); Rajiyah, Harindra (Inventor); Renshaw, Anthony A. (Inventor); Hedeen, Robert A. (Inventor)

    1995-01-01

    A noise source for an aircraft engine active noise cancellation system in which the resonant frequency of noise radiating structure is tuned to permit noise cancellation over a wide range of frequencies. The resonant frequency of the noise radiating structure is tuned by a plurality of drivers arranged to contact the noise radiating structure. Excitation of the drivers causes expansion or contraction of the drivers, thereby varying the edge loading applied to the noise radiating structure. The drivers are actuated by a controller which receives input of a feedback signal proportional to displacement of the noise radiating element and a signal corresponding to the blade passage frequency of the engine's fan. In response, the controller determines a control signal which is sent to the drivers, causing them to expand or contract. The noise radiating structure may be either the outer shroud of the engine or a ring mounted flush with an inner wall of the shroud or disposed in the interior of the shroud.

  12. Ring the bell for Matins: circadian adaptation to split sleep by cloistered monks and nuns.

    PubMed

    Arnulf, Isabelle; Brion, Agnès; Pottier, Michel; Golmard, Jean-Louis

    2011-12-01

    Cloistered monks and nuns adhere to a 10-century-old strict schedule with a common zeitgeber of a night split by a 2- to 3-h-long Office (Matins). The authors evaluated how the circadian core body temperature rhythm and sleep adapt in cloistered monks and nuns in two monasteries. Five monks and five nuns following the split-sleep night schedule for 5 to 46 yrs without interruption and 10 controls underwent interviews, sleep scales, and physical examination and produced a week-long sleep diary and actigraphy, plus 48-h recordings of core body temperature. The circadian rhythm of temperature was described by partial Fourier time-series analysis (with 12- and 24-h harmonics). The temperature peak and trough values and clock times did not differ between groups. However, the temperature rhythm was biphasic in monks and nuns, with an early decrease at 19:39 ± 4:30 h (median ± 95% interval), plateau or rise of temperature at 22:35 ± 00:23 h (while asleep) lasting 296 ± 39 min, followed by a second decrease after the Matins Office, and a classical morning rise. Although they required alarm clocks to wake-up for Matins at midnight, the body temperature rise anticipated the nocturnal awakening by 85 ± 15 min. Compared to the controls, the monks and nuns had an earlier sleep onset (20:05 ± 00:59 h vs. 00:00 ± 00:54 h, median ± 95% confidence interval, p= .0001) and offset (06:27 ± 0:22 h, vs. 07:37 ± 0:33 h, p= .0001), as well as a shorter sleep time (6.5 ± 0.6 vs. 7.6 ± 0.7 h, p= .05). They reported difficulties with sleep latency, sleep duration, and daytime function, and more frequent hypnagogic hallucinations. In contrast to their daytime silence, they experienced conversations (and occasionally prayers) in dreams. The biphasic temperature profile in monks and nuns suggests the human clock adapts to and even anticipates nocturnal awakenings. It resembles the biphasic sleep and rhythm of healthy volunteers transferred to a short (10-h) photoperiod and provides

  13. Actin Rings of Power.

    PubMed

    Schwayer, Cornelia; Sikora, Mateusz; Slováková, Jana; Kardos, Roland; Heisenberg, Carl-Philipp

    2016-06-20

    Circular or ring-like actin structures play important roles in various developmental and physiological processes. Commonly, these rings are composed of actin filaments and myosin motors (actomyosin) that, upon activation, trigger ring constriction. Actomyosin ring constriction, in turn, has been implicated in key cellular processes ranging from cytokinesis to wound closure. Non-constricting actin ring-like structures also form at cell-cell contacts, where they exert a stabilizing function. Here, we review recent studies on the formation and function of actin ring-like structures in various morphogenetic processes, shedding light on how those different rings have been adapted to fulfill their specific roles. PMID:27326928

  14. Application of composite insulators to transmission lines

    SciTech Connect

    Cherney, E.A.; Brown, R.L.; Karady, G.; Nicholls, J.L.; Orbeck, T.; Pargamin, L.

    1983-05-01

    The paper provides guidelines for the application of composite insulators to transmission lines. These guidelines are based on utility field experiences, results of research laboratory tests and manufacturers' recommendations. Discussed are interchangeability with porcelain and glass insulators, application in contaminated environments, material ageing, insulator icing, the use of grease, resistance to vandalism, temperature extremes, and the need for grading rings. Clarification is provided on the mechanical rating of composite insulators because there is not yet general agreement by various industry groups.

  15. Insulator for laser housing

    DOEpatents

    Duncan, D.B.

    1992-12-29

    The present invention provides a heat-resistant electrical insulator adapted for joining laser housing portions, which insulator comprises: an annulus; a channel in the annulus traversing the circumference and length of the housing; at least two ports, each communicating with the channel and an outer surface of the housing; and an attachment for securely attaching each end of the annulus to a laser housing member. 3 figs.

  16. Insulator for laser housing

    DOEpatents

    Duncan, David B.

    1992-01-01

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

  17. A highly-sensitive NaCl concentration sensor based on a compact silicon-on-insulator micro-ring resonator

    NASA Astrophysics Data System (ADS)

    Zhou, Jie; Wang, Wanjun; Wang, Yiqun; Feng, Junbo; Guo, Jin

    2015-10-01

    Silicon photonics circuit has been widely investigated in recent years, due to its advantage in the small footprint, high density integration and compatible with CMOS pilot line. In this paper, a compact, highly-sensitivity NaCl concentration sensor is experimentally demonstrated, based on the micro-ring resonators. The sensor circuit is composed of grating couplers, bus waveguide and micro-ring resonators. The width of optical waveguides is 450nm, with a thickness of 220nm. The chip was fabricated in imec through the ePIXfab multi-project wafer service supported by our group, which is compatible with the CMOS process line. The chip shows high sensitivity, as high as of more than 80nm/RIU, which corresponding to a detection limit of 1.6e-4 by using optical spectrum analyzer.

  18. Exploring the size adaptability of the B ring binding zone of the colchicine site of tubulin with para-nitrogen substituted isocombretastatins.

    PubMed

    Jiménez, Carmen; Ellahioui, Younes; Álvarez, Raquel; Aramburu, Laura; Riesco, Alejandra; González, Myriam; Vicente, Alba; Dahdouh, Abdelaziz; Ibn Mansour, Ahmed; Jiménez, Carlos; Martín, Diego; Sarmiento, Rogelio G; Medarde, Manuel; Caballero, Esther; Peláez, Rafael

    2015-07-15

    We have synthesized and assayed dimethylaminophenyl, pyrrolidin-1-ylphenyl and carbazole containing phenstatins and isocombretastatins as analogues of the highly potent indoleisocombretastatins with extended or reduced ring sizes. This is an attempt to explore beyond the structural constraints of the X-ray crystal structures the zone of the colchicine site where the tropolone ring of colchicine binds to tubulin (zone 1). The isocombretastatins display up to 30 fold increased water solubility when compared with combretastatin A-4, potent inhibition of tubulin polymerization, and nanomolar cytotoxicities against several human cancer cell lines irrespective of the size of the B ring. On the other hand, substitutions ortho to the nitrogen cause an important reduction in potency. We have also shown that representative compounds inhibit autophagy. These results show that zone 1 can adapt to systems of different size as far as they stay in a common plane, but does not tolerate substituents protruding above or below it. These results can help in the understanding of the binding modes of structures with similar systems and in the design of new colchicine site ligands.

  19. Highly adaptive RF excitation scheme based on conformal resonant CRLH metamaterial ring antennas for 7-Tesla traveling-wave magnetic resonance imaging.

    PubMed

    Erni, Daniel; Liebig, Thorsten; Rennings, Andreas; Koster, Norbert H L; Fröhlich, Jürg

    2011-01-01

    We propose an adaptive RF antenna system for the excitation (and manipulation) of the fundamental circular waveguide mode (TE(11)) in the context of high-field (7T) traveling-wave magnetic resonance imaging (MRI). The system consists of composite right-/left-handed (CRLH) meta-material ring antennas that fully conforms to the inner surface of the MRI bore. The specific use of CRLH metamaterials is motivated by its inherent dispersion engineering capabilities, which is needed when designing resonant ring structures for virtually any predefined diameter operating at the given Larmor frequency (i.e. 298 MHz). Each functional group of the RF antenna system consists of a pair of subsequently spaced and correspondingly fed CRLH ring antennas, allowing for the unidirectional excitation of propagating, circularly polarized B(1) mode fields. The same functional group is also capable to simultaneously mold an incoming, counter-propagating mode. Given these functionalities we are proposing now a compound scheme (i.e. periodically arranged multiple antenna pairs)--termed as "MetaBore"--that is apt to provide a tailored RF power distribution as well as full wave reflection compensation virtually at any desired location along the bore.

  20. 110 GHz hybrid mode-locked fiber laser with enhanced extinction ratio based on nonlinear silicon-on-insulator micro-ring-resonator (SOI MRR)

    NASA Astrophysics Data System (ADS)

    Liu, Yang; Hsu, Yung; Chow, Chi-Wai; Yang, Ling-Gang; Yeh, Chien-Hung; Lai, Yin-Chieh; Tsang, Hon-Ki

    2016-03-01

    We propose and experimentally demonstrate a new 110 GHz high-repetition-rate hybrid mode-locked fiber laser using a silicon-on-insulator microring-resonator (SOI MRR) acting as the optical nonlinear element and optical comb filter simultaneously. By incorporating a phase modulator (PM) that is electrically driven at a fraction of the harmonic frequency, an enhanced extinction ratio (ER) of the optical pulses can be produced. The ER of the optical pulse train increases from 3 dB to 10 dB. As the PM is only electrically driven by the signal at a fraction of the harmonic frequency, in this case 22 GHz (110 GHz/5 GHz), a low bandwidth PM and driving circuit can be used. The mode-locked pulse width and the 3 dB spectral bandwidth of the proposed mode-locked fiber laser are measured, showing that the optical pulses are nearly transform limited. Moreover, stability evaluation for an hour is performed, showing that the proposed laser can achieve stable mode-locking without the need for optical feedback or any other stabilization mechanism.

  1. The Polar Insulation Investigation

    ERIC Educational Resources Information Center

    Urban-Rich, Juanita

    2006-01-01

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

  2. Note: O-ring stack system for electron gun alignment.

    PubMed

    Park, In-Yong; Cho, Boklae; Han, Cheolsu; Shin, Seungmin; Lee, Dongjun; Ahn, Sang Jung

    2015-01-01

    We present a reliable method for aligning an electron gun which consists of an electron source and lenses by controlling a stack of rubber O-rings in a vacuum condition. The beam direction angle is precisely tilted along two axes by adjusting the height difference of a stack of O-rings. In addition, the source position is shifted in each of three orthogonal directions. We show that the tilting angle and linear shift along the x and y axes as obtained from ten stacked O-rings are ±2.55° and ±2 mm, respectively. This study can easily be adapted to charged particle gun alignment and adjustments of the flange position in a vacuum, ensuring that its results can be useful with regard to electrical insulation between flanges with slight modifications. PMID:25638137

  3. Note: O-ring stack system for electron gun alignment

    NASA Astrophysics Data System (ADS)

    Park, In-Yong; Cho, Boklae; Han, Cheolsu; Shin, Seungmin; Lee, Dongjun; Ahn, Sang Jung

    2015-01-01

    We present a reliable method for aligning an electron gun which consists of an electron source and lenses by controlling a stack of rubber O-rings in a vacuum condition. The beam direction angle is precisely tilted along two axes by adjusting the height difference of a stack of O-rings. In addition, the source position is shifted in each of three orthogonal directions. We show that the tilting angle and linear shift along the x and y axes as obtained from ten stacked O-rings are ±2.55° and ±2 mm, respectively. This study can easily be adapted to charged particle gun alignment and adjustments of the flange position in a vacuum, ensuring that its results can be useful with regard to electrical insulation between flanges with slight modifications.

  4. Note: O-ring stack system for electron gun alignment

    SciTech Connect

    Park, In-Yong; Cho, Boklae; Han, Cheolsu; Shin, Seungmin; Lee, Dongjun; Ahn, Sang Jung

    2015-01-15

    We present a reliable method for aligning an electron gun which consists of an electron source and lenses by controlling a stack of rubber O-rings in a vacuum condition. The beam direction angle is precisely tilted along two axes by adjusting the height difference of a stack of O-rings. In addition, the source position is shifted in each of three orthogonal directions. We show that the tilting angle and linear shift along the x and y axes as obtained from ten stacked O-rings are ±2.55° and ±2 mm, respectively. This study can easily be adapted to charged particle gun alignment and adjustments of the flange position in a vacuum, ensuring that its results can be useful with regard to electrical insulation between flanges with slight modifications.

  5. Cellulose Insulation

    NASA Technical Reports Server (NTRS)

    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.

  6. Development of a triclosan scaffold which allows for adaptations on both the A- and B-ring for transport peptides

    PubMed Central

    Muench, Stephen P.; Stec, Jozef; Zhou, Ying; Afanador, Gustavo A.; McPhillie, Martin J.; Hickman, Mark; Lee, Patty J.; Leed, Susan E.; Auschwitz, Jennifer M.; Prigge, Sean T.; Rice, David W.; McLeod, Rima

    2013-01-01

    The enoyl acyl-carrier protein reductase (ENR) enzyme is harboured within the apicoplast of apicomplexan parasites providing a significant challenge for drug delivery, which may be overcome through the addition of transductive peptides, which facilitates crossing the apicoplast membranes. The binding site of triclosan, a potent ENR inhibitor, is occluded from the solvent making the attachment of these linkers challenging. Herein, we have produced 3 new triclosan analogues with bulky A- and B-ring motifs, which protrude into the solvent allowing for the future attachment of molecular transporters for delivery. PMID:23664871

  7. Detail of insulator array at first line structure showing historic ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    Detail of insulator array at first line structure showing historic porcelain suspension insulators in strings of eight, porcelain jumper support insulators in strings of six, arch rings and ball weights - Morony Hydroelectric Facility, Morony-to-Rainbow 100 kV Transmission Line, West bank of the Missouri River, Great Falls, Cascade County, MT

  8. Electrical hand tools and techniques: A compilation. [utilization of space technology for tools and adapters

    NASA Technical Reports Server (NTRS)

    1974-01-01

    Space technology utilization for developing tools, adapters, and fixtures and procedures for assembling, installing, and servicing electrical components and equipment are discussed. Some of the items considered are: (1) pivotal screwdriver, (2) termination locator tool for shielded cables, (3) solder application tools, (4) insulation and shield removing tool, and (5) torque wrench adapter for cable connector engaging ring. Diagrams of the various tools and devices are provided.

  9. Performance Enhancement of Space-Time Adaptive Processing for GPS and Microstrip Antenna Design Using Ferrite Rings

    NASA Astrophysics Data System (ADS)

    Rivera-Albino, Alix

    Global Positioning System (GPS) is a navigation system widely used in civilian and military application, but its accuracy is highly impacted with consequential fading, and possible loss of communication due to multipath propagation and high power interferences. This dissertation proposes alternatives to improve the performance of the GPS receivers to obtain a system that can be reliable in critical situations. The basic performance of the GPS receiver consists of receiving the signal with an antenna array, delaying the signal at each antenna element, weighting the delayed replicas, and finally, combining the weighted replicas to estimate the desired signal. Based on these, three modifications are proposed to improve the performance of the system. The first proposed modification is the use of the Least Mean Squares (LMS) algorithm with two variations to decrease the convergence time of the classic LMS while achieving good system stability. The results obtained by the proposed LMS demonstrate that the algorithm can achieve the same stability as the classic LMS using a small step size, and its convergence rate is better than the classic LMS using a large step size. The second proposed modification is to replace the uniform distribution of the time delays (or taps) by an exponential distribution that decreases the bit-error rate (BER) of the system without impacting the computational efficiency of the uniform taps. The results show that, for a BER of 0.001, the system can operate with a 1 to 2 dB lower signal-to-noise ratio (SNR) when an exponential distribution is used rather than a uniform distribution. Finally, the third modification is implemented in the design of the antenna array. In this case, the gain of each microstrip element is enhanced by embedding ferrite rings in the substrate, creating a hybrid substrate. The ferrite rings generates constructive interference between the incident and reflected fields; consequently, the gain of a single microstrip element

  10. Automotive Insulation

    NASA Technical Reports Server (NTRS)

    1997-01-01

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

  11. Thermal Insulation

    NASA Technical Reports Server (NTRS)

    1984-01-01

    Commercially known as Solimide, Temptronics, Inc.'s thermal insulation has application in such vehicles as aircraft, spacecraft and surface transportation systems (i.e. rapid transit cars, trains, buses, and ships) as acoustical treatment for door, wall, and ceiling panels, as a means of reducing vibrations, and as thermal insulation (also useful in industrial equipment). Product originated from research conducted by Johnson Space Center on advanced flame-resistant materials for minimizing fire hazard in the Shuttle and other flight vehicles.

  12. Adapt

    NASA Astrophysics Data System (ADS)

    Bargatze, L. F.

    2015-12-01

    Active Data Archive Product Tracking (ADAPT) is a collection of software routines that permits one to generate XML metadata files to describe and register data products in support of the NASA Heliophysics Virtual Observatory VxO effort. ADAPT is also a philosophy. The ADAPT concept is to use any and all available metadata associated with scientific data to produce XML metadata descriptions in a consistent, uniform, and organized fashion to provide blanket access to the full complement of data stored on a targeted data server. In this poster, we present an application of ADAPT to describe all of the data products that are stored by using the Common Data File (CDF) format served out by the CDAWEB and SPDF data servers hosted at the NASA Goddard Space Flight Center. These data servers are the primary repositories for NASA Heliophysics data. For this purpose, the ADAPT routines have been used to generate data resource descriptions by using an XML schema named Space Physics Archive, Search, and Extract (SPASE). SPASE is the designated standard for documenting Heliophysics data products, as adopted by the Heliophysics Data and Model Consortium. The set of SPASE XML resource descriptions produced by ADAPT includes high-level descriptions of numerical data products, display data products, or catalogs and also includes low-level "Granule" descriptions. A SPASE Granule is effectively a universal access metadata resource; a Granule associates an individual data file (e.g. a CDF file) with a "parent" high-level data resource description, assigns a resource identifier to the file, and lists the corresponding assess URL(s). The CDAWEB and SPDF file systems were queried to provide the input required by the ADAPT software to create an initial set of SPASE metadata resource descriptions. Then, the CDAWEB and SPDF data repositories were queried subsequently on a nightly basis and the CDF file lists were checked for any changes such as the occurrence of new, modified, or deleted

  13. Design and Simulation of an Anode Stalk Support Insulator

    SciTech Connect

    Wang, L; Houck, T; Westenskow, G

    2005-05-16

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

  14. Planetary rings

    SciTech Connect

    Greenberg, R.; Brahic, A.

    1984-01-01

    Among the topics discussed are the development history of planetary ring research, the view of planetary rings in astronomy and cosmology over the period 1600-1900, the characteristics of the ring systems of Saturn and Uranus, the ethereal rings of Jupiter and Saturn, dust-magnetosphere interactions, the effects of radiation forces on dust particles, the collisional interactions and physical nature of ring particles, transport effects due to particle erosion mechanisms, and collision-induced transport processes in planetary rings. Also discussed are planetary ring waves, ring particle dynamics in resonances, the dynamics of narrow rings, the origin and evolution of planetary rings, the solar nebula and planetary disk, future studies of the planetary rings by space probes, ground-based observatories and earth-orbiting satellites, and unsolved problems in planetary ring dynamics.

  15. A decrease in heat insulation of the black-clawed brush-furred rat (Lophuromys melanonyx, Petter) during adaptation to high altitudes.

    PubMed

    Ivlev, Y F; Lavrenchenko, L A

    2016-01-01

    The results of the body-surface infrared thermography of rodents of the genus Lophuromys suggest that heat insulation of the black-clawed brush-furred rat L. melanonyx, a large specialized species of the AfroAlpine zone, is worse than that of the related smaller species, the golden-footed (L. chrysopus) and shorttailed (L. brevicaudus) brush-furred rats, that inhabit tropical forest and Erica shrub, respectively. A decrease in heat insulation of the alpine species may facilitate the use of solar radiation for supporting heat balance of these diurnal animals.

  16. Radiation Insulation

    NASA Technical Reports Server (NTRS)

    1995-01-01

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

  17. Insulation Material

    NASA Technical Reports Server (NTRS)

    1984-01-01

    Manufactured by Hitco Materials Division of Armco, Inc. a ceramic fiber insulation material known as Refrasil has been used extensively as a heat-absorbing ablative reinforcement for such space systems as rocket motor nozzles, combustion chambers, and re-entry shields. Refrasil fibers are highly porous and do not melt or vaporize until fibers exceed 3,100 degrees Fahrenheit. Due to these and other properties, Refrasil has found utility in a number of industrial high temperature applications where glass, asbestos and other materials fail. Hitco used this insulation to assist Richardson Co., Inc. in the manufacturing of hard rubber and plastic molded battery cases.

  18. Microsphere insulation systems

    NASA Technical Reports Server (NTRS)

    Allen, Mark S. (Inventor); Willen, Gary S. (Inventor); Mohling, Robert A. (Inventor)

    2005-01-01

    A new insulation system is provided that contains microspheres. This insulation system can be used to provide insulated panels and clamshells, and to insulate annular spaces around objects used to transfer, store, or transport cryogens and other temperature-sensitive materials. This insulation system provides better performance with reduced maintenance than current insulation systems.

  19. The liquid metal slip ring experiment for the communications technology satellite

    NASA Technical Reports Server (NTRS)

    Lovell, R. R.

    1972-01-01

    The experiment is designed to demonstrate liquid metal slip ring (LMSR) performance in a space environment. An evaluation was made of the features of the LMSR where improvement in performance over conventional slip rings was expected. The primary measurements to be made in the experiment will allow a determination of the slip ring electrical resistance, between ring insulation and ring cleanliness.

  20. Saturn's Rings

    NASA Astrophysics Data System (ADS)

    Cuzzi, J. N.

    2014-12-01

    The rings are changing before our eyes; structure varies on all timescales and unexpected things have been discovered. Many questions have been answered, but some answers remain elusive (see Cuzzi et al 2010 for a review). Here we highlight the major ring science progress over the mission to date, and describe new observations planned for Cassini's final three years. Ring Composition and particle sizes: The rings are nearly all water ice with no other ices - so why are they reddish? The C Ring and Cassini Division are "dirtier" than the more massive B and A Rings, as shown by near-IR and, recently, microwave observations. Particle sizes, from stellar and radio occultations, vary from place to place. Ring structure, micro and macro: numerous spiral density waves and ubiquitous "self-gravity wakes" reveal processes which fostered planet formation in the solar system and elsewhere. However, big puzzles remain regarding the main ring divisions, the C Ring plateau structures, and the B Ring irregular structure. Moonlets, inside and out, seen and unseen: Two gaps contain sizeable moonlets, but more gaps seem to contain none; even smaller embedded "propeller" objects wander, systematically or randomly, through the A ring. Rubble pile ringmoons just outside the rings may escaped from the rings, and the recently discovered "Peggy" may be trying this as we watch. Impact bombardment of the rings: Comet fragments set the rings to rippling on century-timescales, and boulders crash through hourly; meanwhile, the constant hail of infalling Kuiper belt material has a lower mass flux than previously thought. Origin and Age of the Rings: The ring mass and bombardment play key roles. The ring mass is well known everywhere but in the B Ring (where most of it is). New models suggest how tidal breakup of evolving moons may have formed massive ancient rings, of which the current ring is just a shadow. During its last three years, the Cassini tour profile will allow entirely new

  1. Planetary rings

    NASA Technical Reports Server (NTRS)

    Cook, A. F.

    1980-01-01

    Observations of the Rings of Saturn from the Pioneer spacecraft, discovery of the Ring of Jupiter, ground based polarimetry of the Rings of Saturn and some theoretical studies may be combined to markedly advance our understanding of the Rings of Jupiter, Saturn and Uranus. In particular, narrow rings can be self-gravitatingly stable inside Roche's limit and outside another closer limit. They can be created from a satellite which evolves across its Roche limit either by inward tidal drift or by growth of the planet by accretion. These considerations suggest that Neptune may well be surrounded by one or more narrow rings like those of Uranus.

  2. Helmet latching and attaching ring

    NASA Technical Reports Server (NTRS)

    Chase, E. W.; Viikinsalo, S. J. (Inventor)

    1970-01-01

    A neck ring releasably secured to a pressurized garment carries an open-ended ring normally in the engagement position fitted into an annular groove and adapted to fit into a complementary annular groove formed in a helmet. Camming means formed on the inner surface at the end of the helmet engages the open-ended ring to retract the same and allow for one motion donning even when the garment is pressurized. A projection on the end of the split ring is engageable to physically retract the split ring.

  3. Neptune's rings

    NASA Technical Reports Server (NTRS)

    1999-01-01

    This 591-second exposure of the rings of Neptune were taken with the clear filter by the Voyager 2 wide-angle camera. The two main rings are clearly visible and appear complete over the region imaged. Also visible in this image is the inner faint ring and the faint band which extends smoothly from the ring roughly halfway between the two bright rings. Both of these newly discovered rings are broad and much fainter than the two narrow rings. The bright glare is due to over-exposure of the crescent on Neptune. Numerous bright stars are evident in the background. Both bright rings have material throughout their entire orbit, and are therefore continuous. The Voyager Mission is conducted by JPL for NASA's Office of Space Science and Applications.

  4. Vascular ring

    MedlinePlus

    ... with aberrant subclavian and left ligamentum ateriosus; Congenital heart defect - vascular ring; Birth defect heart - vascular ring ... accounts for less than 1% of all congenital heart problems. The condition occurs as often in males ...

  5. Ground Movement in SSRL Ring

    SciTech Connect

    Sunikumar, Nikita; /UCLA /SLAC

    2011-08-25

    Users of the Stanford Synchrotron Radiation Lightsource (SSRL) are being affected by diurnal motion of the synchrotron's storage ring, which undergoes structural changes due to outdoor temperature fluctuations. In order to minimize the effects of diurnal temperature fluctuations, especially on the vertical motion of the ring floor, scientists at SSRL tried three approaches: painting the storage ring white, covering the asphalt in the middle of the ring with highly reflective Mylar and installing Mylar on a portion of the ring roof and walls. Vertical motion in the storage ring is measured by a Hydrostatic Leveling System (HLS), which calculates the relative height of water in a pipe that extends around the ring. The 24-hr amplitude of the floor motion was determined using spectral analysis of HLS data, and the ratio of this amplitude before and after each experiment was used to quantitatively determine the efficacy of each approach. The results of this analysis showed that the Mylar did not have any significant effect on floor motion, although the whitewash project did yield a reduction in overall HLS variation of 15 percent. However, further analysis showed that the reduction can largely be attributed to a few local changes rather than an overall reduction in floor motion around the ring. Future work will consist of identifying and selectively insulating these local regions in order to find the driving force behind diurnal floor motion in the storage ring.

  6. SEALED INSULATOR BUSHING

    DOEpatents

    Carmichael, H.

    1952-11-11

    The manufacture of electrode insulators that are mechanically strong, shock-proof, vacuum tight, and are capable of withstanding gas pressures of many atmospheres under intense neutron bombardment, such as may be needed in an ionization chamber, is described. The ansulator comprises a bolt within a quartz tube, surrounded by a bushing held in place by two quartz rings, and tightened to a pressure of 1,000 pounds per square inch by a nut and washer. Quartz is the superior material to meet these conditions, however, to withstand this pressure the quartz must be fire polished, lapped to form smooth and parallel surfaces, and again fire polished to form an extremely smooth and fracture resistant mating surface.

  7. Tank Insulation

    NASA Technical Reports Server (NTRS)

    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.

  8. Insulators for high voltages

    SciTech Connect

    Looms, J.S.T.

    1987-01-01

    This book describes electrical insulators for high voltage applications. Topics considered include the insulating materials, the manufacture of wet process porcelain, the manufacture of tempered glass, the glass-fibre core, the polymeric housing, the common problem - terminating an insulator, mechanical constraints, the physics of pollution flashover, the physics of contamination, testing of insulators, conclusions from testing, remedies for flashover, insulators for special cases, interference and noise, and the insulator of the future.

  9. Adaptation of the pseudo-metal-oxide-semiconductor field effect transistor technique to ultrathin silicon-on-insulator wafers characterization: Improved set-up, measurement procedure, parameter extraction, and modeling

    NASA Astrophysics Data System (ADS)

    Van Den Daele, W.; Malaquin, C.; Baumel, N.; Kononchuk, O.; Cristoloveanu, S.

    2013-10-01

    This paper revisits and adapts of the pseudo-MOSFET (Ψ-MOSFET) characterization technique for advanced fully depleted silicon on insulator (FDSOI) wafers. We review the current challenges for standard Ψ-MOSFET set-up on ultra-thin body (12 nm) over ultra-thin buried oxide (25 nm BOX) and propose a novel set-up enabling the technique on FDSOI structures. This novel configuration embeds 4 probes with large tip radius (100-200 μm) and low pressure to avoid oxide damage. Compared with previous 4-point probe measurements, we introduce a simplified and faster methodology together with an adapted Y-function. The models for parameters extraction are revisited and calibrated through systematic measurements of SOI wafers with variable film thickness. We propose an in-depth analysis of the FDSOI structure through comparison of experimental data, TCAD (Technology Computed Aided Design) simulations, and analytical modeling. TCAD simulations are used to unify previously reported thickness-dependent analytical models by analyzing the BOX/substrate potential and the electrical field in ultrathin films. Our updated analytical models are used to explain the results and to extract correct electrical parameters such as low-field electron and hole mobility, subthreshold slope, and film/BOX interface traps density.

  10. Planetary Rings

    NASA Technical Reports Server (NTRS)

    Cuzzi, Jeffrey N.

    1994-01-01

    Just over two decades ago, Jim Pollack made a critical contribution to our understanding of planetary ring particle properties, and resolved a major apparent paradox between radar reflection and radio emission observations. At the time, particle properties were about all there were to study about planetary rings, and the fundamental questions were, why is Saturn the only planet with rings, how big are the particles, and what are they made of? Since then, we have received an avalanche of observations of planetary ring systems, both from spacecraft and from Earth. Meanwhile, we have seen steady progress in our understanding of the myriad ways in which gravity, fluid and statistical mechanics, and electromagnetism can combine to shape the distribution of the submicron-to-several-meter size particles which comprise ring systems into the complex webs of structure that we now know them to display. Insights gained from studies of these giant dynamical analogs have carried over into improved understanding of the formation of the planets themselves from particle disks, a subject very close to Jim's heart. The now-complete reconnaissance of the gas giant planets by spacecraft has revealed that ring systems are invariably found in association with families of regular satellites, and there is ark emerging perspective that they are not only physically but causally linked. There is also mounting evidence that many features or aspects of all planetary ring systems, if not the ring systems themselves, are considerably younger than the solar system

  11. Ball-joint grounding ring

    NASA Technical Reports Server (NTRS)

    Aperlo, P. J. A.; Buck, P. A.; Weldon, V. A.

    1981-01-01

    In ball and socket joint where electrical insulator such as polytetrafluoroethylene is used as line to minimize friction, good electrical contact across joint may be needed for lightning protection or to prevent static-charge build-up. Electrical contact is maintained by ring of spring-loaded fingers mounted in socket. It may be useful in industry for cranes, trailers, and other applications requiring ball and socket joint.

  12. Multiple density layered insulator

    DOEpatents

    Alger, Terry W.

    1994-01-01

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

  13. Multiple density layered insulator

    DOEpatents

    Alger, T.W.

    1994-09-06

    A multiple density layered insulator for use with a laser is disclosed which provides at least two different insulation materials for a laser discharge tube, where the two insulation materials have different thermoconductivities. The multiple layer insulation materials provide for improved thermoconductivity capability for improved laser operation. 4 figs.

  14. Calcium silicate insulation structure

    DOEpatents

    Kollie, Thomas G.; Lauf, Robert J.

    1995-01-01

    An insulative structure including a powder-filled evacuated casing utilizes a quantity of finely divided synthetic calcium silicate having a relatively high surface area. The resultant structure-provides superior thermal insulating characteristics over a broad temperature range and is particularly well-suited as a panel for a refrigerator or freezer or the insulative barrier for a cooler or a insulated bottle.

  15. Fragile Mott insulators.

    PubMed

    Yao, Hong; Kivelson, Steven A

    2010-10-15

    We prove that there exists a class of crystalline insulators, which we call "fragile Mott insulators," which are not adiabatically connected to any sort of band insulator provided time-reversal and certain point-group symmetries are respected, but which are otherwise unspectacular in that they exhibit no topological order nor any form of fractionalized quasiparticles. Different fragile Mott insulators are characterized by different nontrivial one-dimensional representations of the crystal point group. We illustrate this new type of insulators with two examples: the d Mott insulator discovered in the checkerboard Hubbard model at half-filling and the Affleck-Kennedy-Lieb-Tasaki insulator on the square lattice.

  16. Jupiter's ring

    NASA Technical Reports Server (NTRS)

    1979-01-01

    First evidence of a ring around the planet Jupiter is seen in this photograph taken by Voyager 1 on March 4, 1979. The multiple exposure of the extremely thin faint ring appears as a broad light band crossing the center of the picture. The edge of the ring is 1,212,000 km from the spacecraft and 57,000 km from the visible cloud deck of Jupiter. The background stars look like broken hair pins because of spacecraft motion during the 11 minute 12 second exposure. The wavy motion of the star trails is due to the ultra-slow natural oscillation of the spacecraft (with a period of 78 seconds). The black dots are geometric calibration points in the camera. The ring thickness is estimated to be 30 km or less. The photograph was part of a sequence planned to search for such rings in Jupiter's equatorial plane. The ring has been invisible from Earth because of its thinness and its transparency when viewed at any angle except straight on. JPL manages and controls the Voyager Project for NASA's Office of Space Science.

  17. Home Insulation

    NASA Technical Reports Server (NTRS)

    1994-01-01

    Under the Guaranteed Watt Savers (GWS) system, plans for a new home are computer analyzed for anticipated heat loss and gain. Specifications are specifically designed for each structure and a Smart- House Radiant Barrier is installed. Designed to reflect away 95% of the Sun's radiant energy, the radiant barrier is an adaptation of an aluminum shield used on Apollo spacecraft. On completion of a home, technicians using a machine, check for air tightness, by creating a vacuum in the house and computer calculations that measure the amount of air exchanged. A guarantee that only the specified number kilowatt hours will be used is then provided.

  18. Topological crystalline insulators.

    PubMed

    Fu, Liang

    2011-03-11

    The recent discovery of topological insulators has revived interest in the band topology of insulators. In this Letter, we extend the topological classification of band structures to include certain crystal point group symmetry. We find a class of three-dimensional "topological crystalline insulators" which have metallic surface states with quadratic band degeneracy on high symmetry crystal surfaces. These topological crystalline insulators are the counterpart of topological insulators in materials without spin-orbit coupling. Their band structures are characterized by new topological invariants. We hope this work will enlarge the family of topological phases in band insulators and stimulate the search for them in real materials.

  19. Hybrid particle traps and conditioning procedure for gas insulated transmission lines

    DOEpatents

    Dale, Steinar J.; Cookson, Alan H.

    1982-01-01

    A gas insulated transmission line includes an outer sheath, an inner condor within the outer sheath, insulating supports supporting the inner conductor within the outer sheath, and an insulating gas electrically insulating the inner conductor from the outer sheath. An apertured particle trapping ring is disposed within the outer sheath, and the trapping ring has a pair of dielectric members secured at each longitudinal end thereof, with the dielectric members extending outwardly from the trapping ring along an arc. A support sheet having an adhesive coating thereon is secured to the trapping ring and disposed on the outer sheath within the low field region formed between the trapping ring and the outer sheath. A conditioning method used to condition the transmission line prior to activation in service comprises applying an AC voltage to the inner conductor in a plurality of voltage-time steps, with the voltage-time steps increasing in voltage magnitude while decreasing in time duration.

  20. Silica reusable surface insulation

    NASA Technical Reports Server (NTRS)

    Goldstein, H. E.; Smith, M.; Leiser, D. B. (Inventor)

    1976-01-01

    A reusable silica surface insulation material is provided by bonding amorphous silica fibers with colloidal silica at an elevated temperature. The surface insulation is ordinarily manufactured in the form of blocks (i.e., tiles).

  1. Ghostly Ring

    NASA Technical Reports Server (NTRS)

    2008-01-01

    [figure removed for brevity, see original site] Click on image for poster version

    This image shows a ghostly ring extending seven light-years across around the corpse of a massive star. The collapsed star, called a magnetar, is located at the exact center of this image. NASA's Spitzer Space Telescope imaged the mysterious ring around magnetar SGR 1900+14 in infrared light. The magnetar itself is not visible in this image, as it has not been detected at infrared wavelengths (it has been seen in X-ray light).

    Magnetars are formed when a massive giant star ends its life in a supernova explosion, leaving behind a super dense neutron star with an incredibly strong magnetic field. The ring seen by Spitzer could not have formed during the original explosion, as any material as close to the star as the ring would have been disrupted by the supernova shock wave. Scientists suspect that the ring my actually be the edges of a bubble that was hollowed out by an explosive burst from the magnetar in 1998. The very bright region near the center of the image is a cluster of young stars, which may be illuminating the inner edge of the bubble, making it look like a ring in projection.

    This composite image was taken using all three of Spitzer's science instruments. The blue color represents 8-micron infrared light taken by the infrared array camera, green is 16-micron light from the infrared spectograph, and red is 24-micron radiation from the multiband imaging photometer.

  2. Cubic topological Kondo insulators.

    PubMed

    Alexandrov, Victor; Dzero, Maxim; Coleman, Piers

    2013-11-27

    Current theories of Kondo insulators employ the interaction of conduction electrons with localized Kramers doublets originating from a tetragonal crystalline environment, yet all Kondo insulators are cubic. Here we develop a theory of cubic topological Kondo insulators involving the interaction of Γ(8) spin quartets with a conduction sea. The spin quartets greatly increase the potential for strong topological insulators, entirely eliminating the weak topological phases from the diagram. We show that the relevant topological behavior in cubic Kondo insulators can only reside at the lower symmetry X or M points in the Brillouin zone, leading to three Dirac cones with heavy quasiparticles.

  3. Insulated solar storage tanks

    SciTech Connect

    Eldighidy, S.M. )

    1991-01-01

    This paper presents the theoretical and experimental investigation of an insulated parallelepiped, outdoor solar, water-filled storage tank of size 1 m {times} 0.5 m {times} 0.3 m, that is made from galvanized iron. The absorption coefficient of the insulating material has been determined. The effects of plastic covers and insulation thickness on the water temperature and the energy gained or lost by water are investigated. Moreover, the effects of insulation thickness on the temperature profiles of the insulating material are discussed. The results show that the absorption coefficient decreases as the insulation thickness increases. Also, it is found that the glass wool insulation of 2.5 cm thickness has the best results compared with the other thicknesses (5 cm, 7.5 cm, and 10 cm) as far as the water temperature and the energy gained by water are concerned.

  4. Cryogenic Insulation Systems

    NASA Technical Reports Server (NTRS)

    Augustynowicz, S. D.; Fesmire, J. E.; Wikstrom, J. P.

    1999-01-01

    The results of a comparative study of cryogenic insulation systems performed are presented. The key aspects of thermal insulation relative to cryogenic system design, testing, manufacturing, and maintenance are discussed. An overview of insulation development from an energy conservation perspective is given. Conventional insulation materials for cryogenic applications provide three levels of thermal conductivity. Actual thermal performance of standard multilayer insulation (MLI) is several times less than laboratory performance and often 10 times worse than ideal performance. The cost-effectiveness of the insulation system depends on thermal performance; flexibility and durability; ease of use in handling, installation, and maintenance; and overall cost including operations, maintenance, and life cycle. Results of comprehensive testing of both conventional and novel materials such as aerogel composites using cryostat boil-off methods are given. The development of efficient, robust cryogenic insulation systems that operate at a soft vacuum level is the primary focus of this paper.

  5. Design validation of the PBFA-Z vacuum insulator stack

    SciTech Connect

    Shoup, R.W.; Long, F.; Martin, T.H.

    1997-07-01

    Sandia has developed PBFA-Z, a 20-MA driver for z-pinch experiments by replacing the water lines, insulator stack. and MITLs on PBFA II with hardware of a new design. The PBFA-Z accelerator was designed to deliver 20 MA to a 15-mg z-pinch load in 100 ns. The accelerator was modeled using circuit codes to determine the time-dependent voltage and current waveforms at the input and output of the water lines, the insulator stack, and the MITLs. The design of the vacuum insulator stack was dictated by the drive voltage, the electric field stress and grading requirements, the water line and MITL interface requirements, and the machine operations and maintenance requirements. The insulator stack consists of four separate modules, each of a different design because of different voltage drive and hardware interface requirements. The shape of the components in each module, i.e., grading rings, insulator rings, flux excluders, anode and cathode conductors, and the design of the water line and MITL interfaces, were optimized by using the electrostatic analysis codes, ELECTRO and JASON. The time-dependent performance of the insulator stacks was evaluated using IVORY, a 2-D PIC code. This paper will describe the insulator stack design, present the results of the ELECTRO and IVORY analyses, and show the results of the stack measurements.

  6. Tribology at high temperature for uncooled heat insulated engine

    SciTech Connect

    Shimauchi, t.; Murakami, T.; Nakagaski, T.; Tsuya, Y.; Umeda, K.

    1984-01-01

    Preliminary study of a heat insulated diesel engine demanded more than 350/sup 0/C operating temperature of the cylinder liner temperature at top ring reversal. In order to define the tribological problems of the engine, a single cylinder endurance run was conducted and friction loss of the six-cylinder heat insulated engine under operating condition was measured. A major tribological problem of piston ring and liner interface was found to be choosing proper wear resisting coatings for their surfaces as the hydrodynamic film protection at top ring reversal reduced significantly. Considering possible applications to the piston ring and cylinder liner sliding faces, several ceramic coating materials were evaluated for their load carrying capacities and wear-resisting properties by laboratory wear test. The results showed that the sliding performances of the coating materials changed considerably depending on the combination of materials and lubricants.

  7. Adaptation of continuous-flow cavity ring-down spectroscopy for batch analysis of δ13C of CO2 and comparison with isotope ratio mass spectrometry.

    PubMed

    Berryman, E M; Marshall, J D; Rahn, T; Cook, S P; Litvak, M

    2011-08-30

    Measurements of δ(13)C in CO(2) have traditionally relied on samples stored in sealed vessels and subsequently analyzed using magnetic sector isotope ratio mass spectrometry (IRMS), an accurate but expensive and high-maintenance analytical method. Recent developments in optical spectroscopy have yielded instruments that can measure δ(13)CO(2) in continuous streams of air with precision and accuracy approaching those of IRMS, but at a fraction of the cost. However, continuous sampling is unsuited for certain applications, creating a need for conversion of these instruments for batch operation. Here, we present a flask (syringe) adaptor that allows the collection and storage of small aliquots (20-30 mL air) for injection into the cavity ring-down spectroscopy (CRDS) instrument. We demonstrate that the adaptor's precision is similar to that of traditional IRMS (standard deviation of 0.3‰ for 385 ppm CO(2) standard gas). In addition, the concentration precision (±0.3% of sample concentration) was higher for CRDS than for IRMS (±7% of sample concentration). Using the adaptor in conjunction with CRDS, we sampled soil chambers and found that soil-respired δ(13)C varied between two different locations in a piñon-juniper woodland. In a second experiment, we found no significant discrimination between the respiration of a small beetle (~5 mm) and its diet. Our work shows that the CRDS system is flexible enough to be used for the analysis of batch samples as well as for continuous sampling. This flexibility broadens the range of applications for which CRDS has the potential to replace magnetic sector IRMS.

  8. Multilayer Insulation Material Guidelines

    NASA Technical Reports Server (NTRS)

    Finckenor, M. M.; Dooling, D.

    1999-01-01

    Multilayer Insulation Material Guidelines provides data on multilayer insulation materials used by previous spacecraft such as Spacelab and the Long-Duration Exposure Facility and outlines other concerns. The data presented in the document are presented for information only. They can be used as guidelines for multilayer insulation design for future spacecraft provided the thermal requirements of each new design and the environmental effects on these materials are taken into account.

  9. Ringing wormholes

    SciTech Connect

    Konoplya, R.A.; Molina, C.

    2005-06-15

    We investigate the response of traversable wormholes to external perturbations through finding their characteristic frequencies and time-domain profiles. The considered solution describes traversable wormholes between the branes in the two brane Randall-Sundrum model and was previously found within Einstein gravity with a conformally coupled scalar field. The evolution of perturbations of a wormhole is similar to that of a black hole and represents damped oscillations (ringing) at intermediately late times, which are suppressed by power-law tails (proportional to t{sup -2} for monopole perturbations) at asymptotically late times.

  10. Topological crystalline insulator nanostructures.

    PubMed

    Shen, Jie; Cha, Judy J

    2014-11-01

    Topological crystalline insulators are topological insulators whose surface states are protected by the crystalline symmetry, instead of the time reversal symmetry. Similar to the first generation of three-dimensional topological insulators such as Bi₂Se₃ and Bi₂Te₃, topological crystalline insulators also possess surface states with exotic electronic properties such as spin-momentum locking and Dirac dispersion. Experimentally verified topological crystalline insulators to date are SnTe, Pb₁-xSnxSe, and Pb₁-xSnxTe. Because topological protection comes from the crystal symmetry, magnetic impurities or in-plane magnetic fields are not expected to open a gap in the surface states in topological crystalline insulators. Additionally, because they have a cubic structure instead of a layered structure, branched structures or strong coupling with other materials for large proximity effects are possible, which are difficult with layered Bi₂Se₃ and Bi₂Te₃. Thus, additional fundamental phenomena inaccessible in three-dimensional topological insulators can be pursued. In this review, topological crystalline insulator SnTe nanostructures will be discussed. For comparison, experimental results based on SnTe thin films will be covered. Surface state properties of topological crystalline insulators will be discussed briefly.

  11. Composite Flexible Blanket Insulation

    NASA Technical Reports Server (NTRS)

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

    1991-01-01

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

  12. Insulated waterproof drainage material

    SciTech Connect

    Tarko, P.L.

    1988-03-15

    An insulative waterproof drainage material is described comprising: a sheet of rigid material having hills and valleys therein to define a core having opposed surfaces; permeable fabric material attached to one of the opposed surfaces; and a layer of thermally insulative material on the other of the opposed surfaces. The insulative material has first surface covering the hills and valleys and a second surface oppositely disposed from the first surface defining an outer surface. The outer surface is spaced a preselected distance D from the hills of the core. The pre-selected distance D define an insulative material thickness corresponding to a pre-selected thermal value.

  13. Alternator insulation evaluation tests

    NASA Technical Reports Server (NTRS)

    Penn, W. B.; Schaefer, R. F.; Balke, R. L.

    1972-01-01

    Tests were conducted to predict the remaining electrical insulation life of a 60 KW homopolar inductor alternator following completion of NASA turbo-alternator endurance tests for SNAP-8 space electrical power systems application. The insulation quality was established for two alternators following completion of these tests. A step-temperature aging test procedure was developed for insulation life prediction and applied to one of the two alternators. Armature winding insulation life of over 80,000 hours for an average winding temperature of 248 degrees C was predicted using the developed procedure.

  14. Loose-fill insulations

    SciTech Connect

    1995-05-01

    Whether you are increasing the insulation levels in your current home or selecting insulation for a new home, choosing the right insulation material can be challenging. Fibrous loose-fill insulations such as cellulose, fiberglass, and rock wool are options you may wish to consider. This publication will introduce you to these materials--what they are, how they are applied, how they compare with each other, and other considerations regarding their use--so that you can decide whether loose fills are right for your home.

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

    DOEpatents

    Cookson, Alan H.; Pederson, Bjorn O.

    1984-01-01

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

  16. Growth Rings.

    ERIC Educational Resources Information Center

    Garmston, Robert J.

    1999-01-01

    In adaptive schools, working groups grow, develop, and learn from experience, becoming more effective as they go. Three premises about group development include the following: each group is unique, some groups mature, and attrition need not block development. Four guidelines for successful group meetings include decide who decides, define the…

  17. Calculating IP Tuning Knobs for the PEP II High Energy Ring using Singular Value Decomposition, Response Matrices and an Adapted Moore Penrose Method

    SciTech Connect

    Wittmer, W.; /SLAC

    2007-11-07

    The PEP II lattices are unique in their detector solenoid field compensation scheme by utilizing a set of skew quadrupoles in the IR region and the adjacent arcs left and right of the IP. Additionally, the design orbit through this region is nonzero. This combined with the strong local coupling wave makes it very difficult to calculate IP tuning knobs which are orthogonal and closed. The usual approach results either in non-closure, not being orthogonal or the change in magnet strength being too big. To find a solution, the set of tuning quads had to be extended which resulted having more degrees of freedom than constraints. To find the optimal set of quadrupoles which creates a linear, orthogonal and closed knob and simultaneously minimizing the changes in magnet strength, the method using Singular Value Decomposition, Response Matrices and an Adapted Moore Penrose method had to be extended. The results of these simulations are discussed below and the results of first implementation in the machine are shown.

  18. Thermal insulation blanket material

    NASA Technical Reports Server (NTRS)

    Pusch, R. H.

    1982-01-01

    A study was conducted to provide a tailorable advanced blanket insulation based on a woven design having an integrally woven core structure. A highly pure quartz yarn was selected for weaving and the cells formed were filled with a microquartz felt insulation.

  19. Insulation Fact Sheet.

    ERIC Educational Resources Information Center

    Conservation and Renewable Energy Inquiry and Referral Service (DOE), Silver Spring, MD.

    Heating and cooling account for 50-70% of the energy consumed in the average American home. Heating water accounts for another 20%. A poorly insulated home loses much of this energy, causing drafty rooms and high energy bills. This fact sheet discusses how to determine if your home needs more insulation, the additional thermal resistance (called…

  20. Breakdown of organic insulators

    NASA Technical Reports Server (NTRS)

    Cuddihy, E. F.

    1983-01-01

    Solar cells and their associated electrical interconnects and leads were encapsulated in transparent elastomeric materials. Their purpose in a photovoltaic module, one of the most important for these elastomeric encapsulation materials, is to function as electrical insulation. This includes internal insulation between adjacent solar cells, between other encapsulated electrical parts, and between the total internal electrical circuitry and external metal frames, grounded areas, and module surfaces. Catastrophic electrical breakdown of the encapsulant insulation materials or electrical current through these materials or module edges to external locations can lead to module failure and can create hazards to humans. Electrical insulation stability, advanced elastomeric encapsulation materials are developed which are intended to be intrinsically free of in-situ ionic impurities, have ultralow water absorption, be weather-stable (UV, oxygen), and have high mechanical flexibility. Efforts to develop a method of assessing the life potential of organic insulation materials in photovoltaic modules are described.

  1. Topological Kondo Insulators

    NASA Astrophysics Data System (ADS)

    Dzero, Maxim; Xia, Jing; Galitski, Victor; Coleman, Piers

    2016-03-01

    This article reviews recent theoretical and experimental work on a new class of topological material -- topological Kondo insulators, which develop through the interplay of strong correlations and spin-orbit interactions. The history of Kondo insulators is reviewed along with the theoretical models used to describe these heavy fermion compounds. The Fu-Kane method of topological classification of insulators is used to show that hybridization between the conduction electrons and localized f electrons in these systems gives rise to interaction-induced topological insulating behavior. Finally, some recent experimental results are discussed, which appear to confirm the theoretical prediction of the topological insulating behavior in samarium hexaboride, where the long-standing puzzle of the residual low-temperature conductivity has been shown to originate from robust surface states.

  2. PBFA-2 vacuum insulator stack failure mechanisms

    NASA Astrophysics Data System (ADS)

    Sweeney, M. A.

    The BPFA-II accelerator includes a large-radius, vertical-axis vacuum insulator stack. The possible failure of the acrylic rings in the stack from electron- or gamma-induced charge buildup is being evaluated. The induced static charges could remain for many hours, and either type of irradiation might cause dendrites to form. Aluminum grading rings sandwiched between the acrylic affect charge accumulation; the acrylic would preferentially break down to these grading rings. The charge buildup and the bremsstrahlung dose could depend critically upon the directionality and position of the electron loss. The effects of electron loss that occurs in the vicinity of the ion diode, where the electrons have energies of about 30 MeV are considered. Monte Carlo electron-photon transport calculations indicate that the bremsstrahlung dose expected in an acrylic ring once diode experiments begin in 1986 could be as much as 5 krads per shot, with roughly half of the photon energy above 5 MeV. Moreover, the calculation indicate that the charge deposition in an individual acrylic ring might exceed 2x10 to the 11 electrons/sq cm.

  3. Cooper Pair Insulators

    NASA Astrophysics Data System (ADS)

    Valles, James

    One of the recent advances in the field of the Superconductor to Insulator Transition (SIT) has been the discovery and characterization of the Cooper Pair Insulator phase. This bosonic insulator, which consists of localized Cooper pairs, exhibits activated transport and a giant magneto-resistance peak. These features differ markedly from the weakly localized transport that emerges as pairs break at a ``fermionic'' SIT. I will describe how our experiments on films nano-patterned with a nearly triangular array of holes have enabled us to 1) distinguish bosonic insulators from fermionic insulators, 2) show that Cooper pairs, rather than quasi-particles dominate the transport in the Cooper Pair insulator phase, 3) demonstrate that very weak, sub nano-meter thickness inhomogeneities control whether a bosonic or fermionic insulator forms at an SIT and 4) reveal that Cooper pairs disintegrate rather than becoming more tightly bound deep in the localized phase. We have also developed a method, using a magnetic field, to tune flux disorder reversibly in these films. I will present our latest results on the influence of magnetic flux disorder and random gauge fields on phenomena near bosonic SITs. This work was performed in collaboration with M. D. Stewart, Jr., Hung Q. Nguyen, Shawna M. Hollen, Jimmy Joy, Xue Zhang, Gustavo Fernandez, Jeffrey Shainline and Jimmy Xu. It was supported by NSF Grants DMR 1307290 and DMR-0907357.

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

    SciTech Connect

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

    1993-08-01

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

  5. Cryogenic insulation development

    NASA Technical Reports Server (NTRS)

    Leonhard, K. E.

    1972-01-01

    Multilayer insulations for long term cryogenic storage are described. The development effort resulted in an insulation concept using lightweight radiation shields, separated by low conductive Dacron fiber tufts. The insulation is usually referred to as Superfloc. The fiber tufts are arranged in a triangular pattern and stand about .040 in. above the radiation shield base. Thermal and structural evaluation of Superfloc indicated that this material is a strong candidate for the development of high performance thermal protection systems because of its high strength, purge gas evacuation capability during boost, its density control and easy application to a tank.

  6. Internal insulation system development

    NASA Technical Reports Server (NTRS)

    Gille, J. P.

    1973-01-01

    The development of an internal insulation system for cryogenic liquids is described. The insulation system is based on a gas layer concept in which capillary or surface tension effects are used to maintain a stable gas layer within a cellular core structure between the tank wall and the contained cryogen. In this work, a 1.8 meter diameter tank was insulated and tested with liquid hydrogen. Ability to withstand cycling of the aluminum tank wall to 450 K was a design and test condition.

  7. Insulation fact sheet

    SciTech Connect

    1997-08-01

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

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

    DOEpatents

    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.

  9. Asymmetric dipolar ring

    DOEpatents

    Prosandeev, Sergey A.; Ponomareva, Inna V.; Kornev, Igor A.; Bellaiche, Laurent M.

    2010-11-16

    A device having a dipolar ring surrounding an interior region that is disposed asymmetrically on the ring. The dipolar ring generates a toroidal moment switchable between at least two stable states by a homogeneous field applied to the dipolar ring in the plane of the ring. The ring may be made of ferroelectric or magnetic material. In the former case, the homogeneous field is an electric field and in the latter case, the homogeneous field is a magnetic field.

  10. Measurement of insulation layers using DTS system

    NASA Astrophysics Data System (ADS)

    Hruby, David; Kajnar, Tomas; Koudelka, Petr; Latal, Jan; Hurta, Jan; Kepak, Stanislav; Jaros, Jakub; Vasinek, Vladimir

    2015-01-01

    Fiber optic distributed temperature sensing systems (DTS) are based on the principle of reflectometer and allow us to measure the temperature along the optical fiber. Optical fiber in these systems is used as a temperature sensor which can measure up to thousands of points simultaneously. DTS sensors use nonlinear phenomenon known as Raman scattering for temperature measurement. The advantages of this system include immunity to electromagnetic radiation, low cost of optical fiber, the possibility of measurement to a distance of 10 km and safe use in flammable or corrosive environments. The small size of optical fiber allows using in applications where the dimensions of the other sensors were problematic. A typical example of the DTS application is the fire detection in tunnels and buildings at risk, detection of water leaks on dikes and dams or monitoring of temperature in mine shafts. This article deals with the measurement of temperature transmission over various insulation layers using the DTS system. One of the problems of temperature transmission is that most of the sensors cannot measure the entire temperature profile but only allows a point measurement. This problem is solved by DTS systems with optical fibers. Optical fiber, due to its small size, can be applied among various insulation layers that were formed by rock wool. Three sensory layers formed by rings of multimode optical tightbuffered fiber with 50/125 micron core/cladding dimension were applied. The layers were linked together allowing a direct comparison of measured temperature. Rows of rings were placed on the margins and one was in the middle. Individual rings were linked together into the horizontal lines. Thus we were able to cover the whole surface of the insulation layers. Measurement was carried out in a closed air-conditioned room for 37 hours. Graphs with the progress of temperature at time and place were compiled from the measured data.

  11. Cooper Pairs in Insulators?!

    SciTech Connect

    James Valles

    2008-07-23

    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. 

  12. Cooper Pairs in Insulators?!

    ScienceCinema

    James Valles

    2016-07-12

    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. 

  13. Composite flexible blanket insulation

    NASA Technical Reports Server (NTRS)

    Kourtides, Demetrius A. (Inventor); Lowe, David M. (Inventor)

    1994-01-01

    An improved composite flexible blanket insulation is presented comprising top silicon carbide having an interlock design, wherein the reflective shield is composed of single or double aluminized polyimide and wherein the polyimide film has a honeycomb pattern.

  14. Repairing ceramic insulating tiles

    NASA Technical Reports Server (NTRS)

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

    1980-01-01

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

  15. Improved Sprayable Insulation

    NASA Technical Reports Server (NTRS)

    Hill, W. F.; Sharpe, M. H.; Lester, C. N.; Echols, Sherman; Simpson, W. G.; Lambert, J. D.; Norton, W. F.; Mclemore, J. P.; Patel, A. K.; Patel, S. V.; Shockney, C. H.; Adams, G. R.; Kelly, M. R.; White, W. T.

    1992-01-01

    MSA-2 and MSA-2A, two similar improved versions of Marshall sprayable ablator, insulating material developed at Marshall Space Flight Center to replace both sheets of cork and MSA-1. Suitable for use on large vehicles and structures exposed to fire or other sources of heat by design or accident. Ablative insulation turns into strong char when exposed to high temperature; highly desireable property in original spacecraft application and possibly in some terrestrial applications.

  16. Photonic Floquet topological insulators.

    PubMed

    Rechtsman, Mikael C; Zeuner, Julia M; Plotnik, Yonatan; Lumer, Yaakov; Podolsky, Daniel; Dreisow, Felix; Nolte, Stefan; Segev, Mordechai; Szameit, Alexander

    2013-04-11

    Topological insulators are a new phase of matter, with the striking property that conduction of electrons occurs only on their surfaces. In two dimensions, electrons on the surface of a topological insulator are not scattered despite defects and disorder, providing robustness akin to that of superconductors. Topological insulators are predicted to have wide-ranging applications in fault-tolerant quantum computing and spintronics. Substantial effort has been directed towards realizing topological insulators for electromagnetic waves. One-dimensional systems with topological edge states have been demonstrated, but these states are zero-dimensional and therefore exhibit no transport properties. Topological protection of microwaves has been observed using a mechanism similar to the quantum Hall effect, by placing a gyromagnetic photonic crystal in an external magnetic field. But because magnetic effects are very weak at optical frequencies, realizing photonic topological insulators with scatter-free edge states requires a fundamentally different mechanism-one that is free of magnetic fields. A number of proposals for photonic topological transport have been put forward recently. One suggested temporal modulation of a photonic crystal, thus breaking time-reversal symmetry and inducing one-way edge states. This is in the spirit of the proposed Floquet topological insulators, in which temporal variations in solid-state systems induce topological edge states. Here we propose and experimentally demonstrate a photonic topological insulator free of external fields and with scatter-free edge transport-a photonic lattice exhibiting topologically protected transport of visible light on the lattice edges. Our system is composed of an array of evanescently coupled helical waveguides arranged in a graphene-like honeycomb lattice. Paraxial diffraction of light is described by a Schrödinger equation where the propagation coordinate (z) acts as 'time'. Thus the helicity of the

  17. Vacuum foil insulation system

    DOEpatents

    Hanson, John P.; Sabolcik, Rudolph E.; Svedberg, Robert C.

    1976-11-16

    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.

  18. Photonic Floquet topological insulators.

    PubMed

    Rechtsman, Mikael C; Zeuner, Julia M; Plotnik, Yonatan; Lumer, Yaakov; Podolsky, Daniel; Dreisow, Felix; Nolte, Stefan; Segev, Mordechai; Szameit, Alexander

    2013-04-11

    Topological insulators are a new phase of matter, with the striking property that conduction of electrons occurs only on their surfaces. In two dimensions, electrons on the surface of a topological insulator are not scattered despite defects and disorder, providing robustness akin to that of superconductors. Topological insulators are predicted to have wide-ranging applications in fault-tolerant quantum computing and spintronics. Substantial effort has been directed towards realizing topological insulators for electromagnetic waves. One-dimensional systems with topological edge states have been demonstrated, but these states are zero-dimensional and therefore exhibit no transport properties. Topological protection of microwaves has been observed using a mechanism similar to the quantum Hall effect, by placing a gyromagnetic photonic crystal in an external magnetic field. But because magnetic effects are very weak at optical frequencies, realizing photonic topological insulators with scatter-free edge states requires a fundamentally different mechanism-one that is free of magnetic fields. A number of proposals for photonic topological transport have been put forward recently. One suggested temporal modulation of a photonic crystal, thus breaking time-reversal symmetry and inducing one-way edge states. This is in the spirit of the proposed Floquet topological insulators, in which temporal variations in solid-state systems induce topological edge states. Here we propose and experimentally demonstrate a photonic topological insulator free of external fields and with scatter-free edge transport-a photonic lattice exhibiting topologically protected transport of visible light on the lattice edges. Our system is composed of an array of evanescently coupled helical waveguides arranged in a graphene-like honeycomb lattice. Paraxial diffraction of light is described by a Schrödinger equation where the propagation coordinate (z) acts as 'time'. Thus the helicity of the

  19. Wrapped Multilayer Insulation

    NASA Technical Reports Server (NTRS)

    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.

  20. Wrapped Multilayer Insulation

    NASA Technical Reports Server (NTRS)

    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/sq m, or 27 percent of the heat leak of conventional MLI (26.7 W/sq m). 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.

  1. Perioperative thermal insulation.

    PubMed

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

    2007-01-01

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

  2. Ring Image Analyzer

    NASA Technical Reports Server (NTRS)

    Strekalov, Dmitry V.

    2012-01-01

    Ring Image Analyzer software analyzes images to recognize elliptical patterns. It determines the ellipse parameters (axes ratio, centroid coordinate, tilt angle). The program attempts to recognize elliptical fringes (e.g., Newton Rings) on a photograph and determine their centroid position, the short-to-long-axis ratio, and the angle of rotation of the long axis relative to the horizontal direction on the photograph. These capabilities are important in interferometric imaging and control of surfaces. In particular, this program has been developed and applied for determining the rim shape of precision-machined optical whispering gallery mode resonators. The program relies on a unique image recognition algorithm aimed at recognizing elliptical shapes, but can be easily adapted to other geometric shapes. It is robust against non-elliptical details of the image and against noise. Interferometric analysis of precision-machined surfaces remains an important technological instrument in hardware development and quality analysis. This software automates and increases the accuracy of this technique. The software has been developed for the needs of an R&TD-funded project and has become an important asset for the future research proposal to NASA as well as other agencies.

  3. Which Ringed Planet...!?

    NASA Astrophysics Data System (ADS)

    2002-12-01

    and the disk of Uranus therefore appears unsually dark. At the same time, the icy material in the rings reflects the sunlight and appears comparatively bright. Uranus is unique among the planets of the solar system in having a tilted rotation axis that is close to the main solar system plane in which most planets move (the "Ecliptic"). At the time of the Voyager-2 encounter (1986), the southern pole was oriented toward the Earth. Now, sixteen years later (corresponding to about one-fifth of Uranus' 84-year period of revolution), we observe the Uranian ring system at an angle that is comparable to the one under which we see Saturn when its ring system is most "open". The moons ESO PR Photo 31b/02 ESO PR Photo 31b/02 [Preview - JPEG: 400 x 526 pix - 76k] [Full-Res - JPEG: 1460 x 1919 pix - 1.1M] Caption : PR Photo 31b/02 provides identifications of the Uranian moons present in PR Photo 31a/02 . The unidentified, round object to the left is a background star. The image scale in indicated by the bar. Seven of the moons of Uranus have been identified in PR Photo 31b/02 [1]. Of these, Titania and Oberon are the brightest (visual magnitude about 14). They were first seen in 1787 by the discoverer of Uranus, William Herschel (1738-1822), working at Bath in England. Ariel and Umbriel were found in 1851 by William Lassell (1799-1880) at Liverpool in the same country. Miranda was discovered in 1948 by Gerard Kuiper (1905-1973) at the 5-m Palomar telescope in California (USA). The much smaller and fainter Puck and Portia (visual magnitude about 21 and barely visible in the photo) were first found in 1985-86 by Stephen P. Synnott of the Jet Propulsion Laboratory (USA), during a study of Voyager-2 photos obtained soon before this NASA spacecraft flew by Uranus in January 1986. Other VLT images If you now want to see a fine VLT photo of Saturn, please look at PR Photo 04a/02 , obtained in late 2001. It was made with the NAOS-CONICA (NACO) Adaptive Optics facility and is therefore

  4. Stirling engine piston ring

    DOEpatents

    Howarth, Roy B.

    1983-01-01

    A piston ring design for a Stirling engine wherein the contact pressure between the piston and the cylinder is maintained at a uniform level, independent of engine conditions through a balancing of the pressure exerted upon the ring's surface and thereby allowing the contact pressure on the ring to be predetermined through the use of a preloaded expander ring.

  5. The rings of Saturn

    NASA Technical Reports Server (NTRS)

    Pollack, J. B.

    1978-01-01

    Consideration is given to the development of theories concerning the rings of Saturn. Particular attention is given to ring structure, noting its thinness, the separations between rings, and observed variations in brightness. Data gathered via infrared, radio and radar techniques are described in terms of ring particle composition and size. Hypotheses about ring origin and evolution are outlined, including the tidal disruption model, calculations of Saturn's gravitational contraction history, grazing, and meteoroid bombardment. Prospects for future observations of Saturn's rings are reviewed, such as the variation in their radar reflectivity as a function of the tilt of the ring plane.

  6. New Dust Belts of Uranus: One Ring, Two Ring, Red Ring, Blue Ring

    SciTech Connect

    de Pater, I; Hammel, H B; Gibbard, S G; Showalter, M R

    2006-02-02

    We compare near-infrared observations of the recently discovered outer rings of Uranus with HST results. We find that the inner ring, R/2003 U 2, is red, whereas the outer ring, R/2003 U 1, is very blue. Blue is an unusual color for rings; Saturn's enigmatic E ring is the only other known example. By analogy to the E ring, R/2003 U 1 is probably produced via impacts into the embedded moon Mab, which apparently orbits at a location where non-gravitational perturbations favor the survival and spreading of sub-micron sized dust. R/2003 U 2 more closely resembles Saturn's G ring.

  7. Tube Dynamics Works for Randomly Entangled Rings.

    PubMed

    Qin, Jian; Milner, Scott T

    2016-02-12

    The tube model is the cornerstone of molecular theory for polymer rheology. We test its microscopic assumptions by simulating topologically equilibrated ring polymers, whose dynamics is free from end segment relaxation. We show that a closed-form expression derived from the tube model adapted to ring polymers quantitatively predicts the segmental mean squared displacements over the entire range of time scales from local motion to complete equilibration, with a time-independent local friction factor.

  8. Thermal insulated glazing unit

    DOEpatents

    Selkowitz, Stephen E.; Arasteh, Dariush K.; Hartmann, John L.

    1991-01-01

    An improved insulated glazing unit is provided which can attain about R5 to about R10 thermal performance at the center of the glass while having dimensions about the same as those of a conventional double glazed insulated glazing unit. An outer glazing and inner glazing are sealed to a spacer to form a gas impermeable space. One or more rigid, non-structural glazings are attached to the inside of the spacer to divide the space between the inner and outer glazings to provide insulating gaps between glazings of from about 0.20 inches to about 0.40 inches. One or more glazing surfaces facing each thermal gap are coated with a low emissivity coating. Finally, the thermal gaps are filled with a low conductance gas such as krypton gas.

  9. Thermal insulated glazing unit

    DOEpatents

    Selkowitz, S.E.; Arasteh, D.K.; Hartmann, J.L.

    1988-04-05

    An improved insulated glazing unit is provided which can attain about R5 to about R10 thermal performance at the center of the glass while having dimensions about the same as those of a conventional double glazed insulated glazing unit. An outer glazing and inner glazing are sealed to a spacer to form a gas impermeable space. One or more rigid, non-structural glazings are attached to the inside of the spacer to divide the space between the inner and outer glazings to provide insulating gaps between glazings of from about 0.20 inches to about 0.40 inches. One or more glazing surfaces facing each thermal gap are coated with a low emissivity coating. Finally, the thermal gaps are filled with a low conductance gas such as krypton gas. 2 figs.

  10. Reusable Surface Insulation

    NASA Technical Reports Server (NTRS)

    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.

  11. Insulation bonding test system

    NASA Technical Reports Server (NTRS)

    Beggs, J. M.; Johnston, G. D.; Coleman, A. D.; Portwood, J. N.; Saunders, J. M.; Redmon, J. W.; Porter, A. C. (Inventor)

    1984-01-01

    A method and a system for testing the bonding of foam insulation attached to metal is described. The system involves the use of an impacter which has a calibrated load cell mounted on a plunger and a hammer head mounted on the end of the plunger. When the impacter strikes the insulation at a point to be tested, the load cell measures the force of the impact and the precise time interval during which the hammer head is in contact with the insulation. This information is transmitted as an electrical signal to a load cell amplifier where the signal is conditioned and then transmitted to a fast Fourier transform (FFT) analyzer. The FFT analyzer produces energy spectral density curves which are displayed on a video screen. The termination frequency of the energy spectral density curve may be compared with a predetermined empirical scale to determine whether a igh quality bond, good bond, or debond is present at the point of impact.

  12. Perioperative thermal insulation.

    PubMed

    Sessler, D I; McGuire, J; Sessler, A M

    1991-05-01

    To determine the efficacy of passive insulators advocated for prevention of cutaneous heat loss, we determined heat loss in unanesthetized volunteers covered by one of the following: a cloth "split sheet" surgical drape; a Convertors disposable-paper split sheet; a Thermadrape disposable laparotomy sheet; an unheated Bair Hugger patient-warming blanket; 1.5-mil-thick plastic hamper bags; and a prewarmed, cotton hospital blanket. Cutaneous heat loss was measured using 10 area-weighted thermal flux transducers while volunteers were exposed to a 20.6 degrees C environment for 1 h. Heat loss decreased significantly from 100 +/- 3 W during the control periods to 69 +/- 6 W (average of all covers) after 1 h of treatment. Heat losses from volunteers insulated by the Thermadrape (61 +/- 6 W) and Bair Hugger covers (64 +/- 5 W) were significantly less than losses from those insulated by plastic bags (77 +/- 11 W). The paper drape (67 +/- 7 W) provided slightly, but not significantly, better insulation than the cloth drape (70 +/- 4 W). Coverage by prewarmed cotton blankets initially resulted in the least heat loss (58 +/- 8 W), but after 40 min, resulted in heat loss significantly greater than that for the Thermadrape (71 +/- 7 W). Regional heat loss was roughly proportional to surface area, and the distribution of regional heat loss remained similar with all covers. These data suggest that cost and convenience should be major factors when choosing among passive perioperative insulating covers. It is likely that the amount of skin surface covered is more important than the choice of skin region covered or the choice of insulating material. PMID:2021204

  13. Measuring Building Insulation

    NASA Astrophysics Data System (ADS)

    Parks, Beth

    2013-03-01

    Currently, the only way for homeowners to learn about the effectiveness of their home insulation is to hire an energy auditor. This difficulty deters homeowners from taking action to improve energy efficiency. In principle, measuring the temperature difference between a wall surface and the interior of a home is sufficient to determine the wall insulation, but in practice, temperature cycles from the heating system make a single measurement unreliable. I will describe a simple and inexpensive thermocouple-based device to measure this temperature difference and report results obtained by monitoring this temperature difference over multiple heating cycles in a range of buildings. Patent application 12/555371

  14. Thermal insulation protection means

    NASA Technical Reports Server (NTRS)

    Dotts, R. L.; Smith, J. A.; Strouhal, G. (Inventor)

    1979-01-01

    A system for providing thermal insulation for portions of a spacecraft which do not exceed 900 F during ascent or reentry relative to the earth's atmosphere is described. The thermal insulation is formed of relatively large flexible sheets of needled Nomex felt having a flexible waterproof coating. The thickness of the felt is sized to protect against projected temperatures and is attached to the structure by a resin adhesive. Vent holes in the sheets allow ventilation while maintaining waterproofing. The system is heat treated to provide thermal stability.

  15. Optimizing Thomson's jumping ring

    NASA Astrophysics Data System (ADS)

    Tjossem, Paul J. H.; Brost, Elizabeth C.

    2011-04-01

    The height to which rings will jump in a Thomson jumping ring apparatus is the central question posed by this popular lecture demonstration. We develop a simple time-averaged inductive-phase-lag model for the dependence of the jump height on the ring material, its mass, and temperature and apply it to measurements of the jump height for a set of rings made by slicing copper and aluminum alloy pipe into varying lengths. The data confirm a peak jump height that grows, narrows, and shifts to smaller optimal mass when the rings are cooled to 77 K. The model explains the ratio of the cooled/warm jump heights for a given ring, the reduction in optimal mass as the ring is cooled, and the shape of the mass resonance. The ring that jumps the highest is found to have a characteristic resistance equal to the inductive reactance of the set of rings.

  16. Self-Healing Wire Insulation

    NASA Technical Reports Server (NTRS)

    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.

  17. Improved insulation material

    NASA Technical Reports Server (NTRS)

    1976-01-01

    Multilayer material consisting of embossed, silver-coated Mylar, nylon net, and silk net is useful for thermal-protection systems and cryogenic containers. Embossing serves two purposes: helps separate radiation barriers and controls radiant energy diffusion. Insulation requires no maintenance after installation.

  18. Alaska Pipeline Insulation

    NASA Technical Reports Server (NTRS)

    1979-01-01

    Crude oil moving through the 800-mile Trans-Alaska Pipeline must be kept at a relatively high temperature, about 180 degrees Fahrenheit, to maintain the fluidity of the oil. In Arctic weather, that demands highly effective insulation. General Electric Co.'s Space Division, Valley Forge, Pennsylvania, provided it with a spinoff product called Therm-O-Trol. Shown being installed on the pipeline, Therm-O-Trol is a metal-bonded polyurethane foam especially formulated for Arctic insulation. A second GE spinoff product, Therm-O-Case, solved a related problem involved in bringing hot crude oil from 2,000-foot-deep wells to the surface without transferring oil heat to the surrounding permafrost soil; heat transfer could melt the frozen terrain and cause dislocations that might destroy expensive well casings. Therm-O-Case is a double-walled oil well casing with multi-layered insulation which provides an effective barrier to heat transfer. Therm-O-Trol and Therm-O-Case are members of a family of insulating products which stemmed from technology developed by GE Space Division in heat transferlthermal control work on Gemini, Apollo and other NASA programs.

  19. Photonic topological insulators.

    PubMed

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

    2013-03-01

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

  20. Insulated ECG electrodes

    NASA Technical Reports Server (NTRS)

    Portnoy, W. M.; David, R. M.

    1973-01-01

    Insulated, capacitively coupled electrode does not require electrolyte paste for attachment. Other features of electrode include wide range of nontoxic material that may be employed for dielectric because of sputtering technique used. Also, electrode size is reduced because there is no need for external compensating networks with FET operational amplifier.

  1. Preassembly Of Insulating Tiles

    NASA Technical Reports Server (NTRS)

    Izu, Y. D.; Yoshioka, E. N.; Rosario, T.

    1988-01-01

    Concept for preassembling high-temperature insulating tiles speeds and simplifies installation and repair and reduces damage from handling. Preassembly concept facilitates placement of tiles on gently contoured surfaces as well as on flat ones. Tiles bonded to nylon mesh with room-temperature-vulcanizing silicon rubber. Spacing between tiles is 0.03 in. Applications include boilers, kilns, and furnaces.

  2. Erosion of polyurethane insulation.

    NASA Technical Reports Server (NTRS)

    Kraus, S.

    1973-01-01

    Detailed description of the test program in which erosion of the spray foam insulation used in the S-II stage of the Saturn-V Apollo launch vehicle was investigated. The behavior of the spray foam was investigated at the elevated temperature and static pressure appropriate to the S-II stage environment, but in the absence of the aerodynamic shear stress.

  3. THERMAL INSULATION SYSTEMS

    NASA Technical Reports Server (NTRS)

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

    2005-01-01

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

  4. Lightweight Electrical Insulation

    NASA Technical Reports Server (NTRS)

    Schroeder, J. E.

    1985-01-01

    Hollow plastic spheres expanded and fused together. Hollow, gasfilled plastic spheres piled in mold. Heating in vacuum softens and expands spheres, forcing them together into nearly regular hexagonal close packing. Foam used as lightweight, electrically insulating material in place of solid ceramic, glass, or polymer. Padding to protect against mechanical shocks another application for such dense, regular foam.

  5. Composite rod insulators for ac power lines; Electrical performance of various designs at a coastal testing station

    SciTech Connect

    Houlgate, R.G.; Swift, D.A. )

    1990-10-01

    The electrical performance of thirty-six composite insulators - of four commercial types for each AC system level of 34.5 kV, 230 kV and 500 kV - has been determined at the CEGB insulator testing station, Brighton, England. The weathershed materials were epoxy-resin, ethylene propylene rubber and silicone rubber; half of the 230 kV insulators had no stress rings. Surface leakage current was recorded for surge levels of 25 mA, 150 mA and 500 mA; a special technique was developed to obtain the flashover statistics of the 500 kV insulators, thereby enabling performance of the composite insulator to be quantified relative to that of a string of cap and pin porcelain insulators of anti-fog design, the deterioration of the insulators was observed by making regular visual inspections. The practical consequences of the findings and the causes of the degradation are discussed.

  6. Peg supported thermal insulation panel

    DOEpatents

    Nowobilski, Jeffert J.; Owens, William J.

    1985-01-01

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

  7. Peg supported thermal insulation panel

    DOEpatents

    Nowobilski, J.J.; Owens, W.J.

    1985-04-30

    A thermal insulation panel which is lightweight, load bearing, accommodates thermal stress, and has excellent high temperature insulation capability comprises high performance insulation between thin metal walls supported by high density, high strength glass pegs made in compliance with specified conditions of time, temperature and pressure. 2 figs.

  8. Multilayer High-Gradient Insulators

    SciTech Connect

    Harris, J R

    2006-08-16

    Multilayer High-Gradient Insulators are vacuum insulating structures composed of thin, alternating layers of dielectric and metal. They are currently being developed for application to high-current accelerators and related pulsed power systems. This paper describes some of the High-Gradient Insulator research currently being conducted at Lawrence Livermore National Laboratory.

  9. Transcription Independent Insulation at TFIIIC-Dependent Insulators

    PubMed Central

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

    2009-01-01

    Chromatin insulators separate active from repressed chromatin domains. In yeast the RNA pol III transcription machinery bound to tRNA genes function with histone acetylases and chromatin remodelers to restrict the spread of heterochromatin. Our results collectively demonstrate that binding of TFIIIC is necessary for insulation but binding of TFIIIB along with TFIIIC likely improves the probability of complex formation at an insulator. Insulation by this transcription factor occurs in the absence of RNA polymerase III or polymerase II but requires specific histone acetylases and chromatin remodelers. This analysis identifies a minimal set of factors required for insulation. PMID:19596900

  10. Insulative laser shell coupler

    DOEpatents

    Arnold, Phillip A.; Anderson, Andrew T.; Alger, Terry W.

    1994-01-01

    A segmented coaxial laser shell assembly having at least two water jacket sections, two pairs of interconnection half rings, a dialectric break ring, and a pair of threaded ring sections. Each water jacket section with an inner tubular section that defines an inner laser cavity with water paths adjacent to at least a portion of the exterior of the inner tubular section, and mating faces at the end of the water jacket section through which the inner laser cavity opens and which defines at least one water port therethrough in communication with the water jackets. The water paths also define in their external surface a circumferential notch set back from and in close proximity to the mating face. The dielectric break ring has selected thickness and is placed between, and in coaxial alignment with, the mating faces of two of the adjacent water jacket sections. The break ring also defines an inner laser cavity of the same size and shape as the inner laser cavity of the water jacket sections and at least one water passage through the break ring to communicate with at least one water port through the mating faces of the water jacket sections.

  11. Insulative laser shell coupler

    DOEpatents

    Arnold, P.A.; Anderson, A.T.; Alger, T.W.

    1994-09-20

    A segmented coaxial laser shell assembly having at least two water jacket sections, two pairs of interconnection half rings, a dielectric break ring, and a pair of threaded ring sections is disclosed. Each water jacket section with an inner tubular section that defines an inner laser cavity with water paths adjacent to at least a portion of the exterior of the inner tubular section, and mating faces at the end of the water jacket section through which the inner laser cavity opens and which defines at least one water port therethrough in communication with the water jackets. The water paths also define in their external surface a circumferential notch set back from and in close proximity to the mating face. The dielectric break ring has selected thickness and is placed between, and in coaxial alignment with, the mating faces of two of the adjacent water jacket sections. The break ring also defines an inner laser cavity of the same size and shape as the inner laser cavity of the water jacket sections and at least one water passage through the break ring to communicate with at least one water port through the mating faces of the water jacket sections. 4 figs.

  12. Integrated Multilayer Insulation

    NASA Technical Reports Server (NTRS)

    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. Vascular ring (image)

    MedlinePlus

    Vascular ring is a term used to describe a number of abnormal formations of the aorta, the large artery ... the pulmonary artery. The abnormal vessel(s) forms a ring, which encircles and may press down on the ...

  14. New dust belts of Uranus: one ring, two ring, red ring, blue ring.

    PubMed

    de Pater, Imke; Hammel, Heidi B; Gibbard, Seran G; Showalter, Mark R

    2006-04-01

    We compared near-infrared observations of the recently discovered outer rings of Uranus with Hubble Space Telescope results. We find that the inner ring, R/2003 U 2, is red, whereas the outer ring, R/2003 U 1, is very blue. Blue is an unusual color for rings; Saturn's enigmatic E ring is the only other known example. By analogy to the E ring, R/2003 U 1 is probably produced by impacts into the embedded moon Mab, which apparently orbits at a location where nongravitational perturbations favor the survival and spreading of submicron-sized dust. R/2003 U 2 more closely resembles Saturn's G ring, which is red, a typical color for dusty rings. PMID:16601188

  15. New dust belts of Uranus: one ring, two ring, red ring, blue ring.

    PubMed

    de Pater, Imke; Hammel, Heidi B; Gibbard, Seran G; Showalter, Mark R

    2006-04-01

    We compared near-infrared observations of the recently discovered outer rings of Uranus with Hubble Space Telescope results. We find that the inner ring, R/2003 U 2, is red, whereas the outer ring, R/2003 U 1, is very blue. Blue is an unusual color for rings; Saturn's enigmatic E ring is the only other known example. By analogy to the E ring, R/2003 U 1 is probably produced by impacts into the embedded moon Mab, which apparently orbits at a location where nongravitational perturbations favor the survival and spreading of submicron-sized dust. R/2003 U 2 more closely resembles Saturn's G ring, which is red, a typical color for dusty rings.

  16. Fiber Ring Optical Gyroscope (FROG)

    NASA Technical Reports Server (NTRS)

    1979-01-01

    The design, construction, and testing of a one meter diameter fiber ring optical gyro, using 1.57 kilometers of single mode fiber, are described. The various noise components: electronic, thermal, mechanical, and optical, were evaluated. Both dc and ac methods were used. An attempt was made to measure the Earth rotation rate; however, the results were questionable because of the optical and electronic noise present. It was concluded that fiber ring optical gyroscopes using all discrete components have many serious problems that can only be overcome by discarding the discrete approach and adapting an all integrated optic technique that has the laser source, modulator, detector, beamsplitters, and bias element on a single chip.

  17. Saturn's F-Ring

    NASA Technical Reports Server (NTRS)

    2000-01-01

    This narrow-angle camera image of Saturn's F Ring was taken through the Clear filter while at a distance of 6.9 million km from Saturn on 8 November 1980. The brightness variations of this tightly-constrained ring shown here indicate that the ring is less uniform in makeup than the larger rings. JPL managed the Voyager Project for NASA's Office of Space Science

  18. Multilayer High-Gradient Insulators

    SciTech Connect

    Harris, J R; Anaya, R M; Blackfield, D; Chen, Y -; Falabella, S; Hawkins, S; Holmes, C; Paul, A C; Sampayan, S; Sanders, D M; Watson, J A; Caporaso, G J; Krogh, M

    2006-11-15

    High voltage systems operated in vacuum require insulating materials to maintain spacing between conductors held at different potentials, and may be used to maintain a nonconductive vacuum boundary. Traditional vacuum insulators generally consist of a single material, but insulating structures composed of alternating layers of dielectric and metal can also be built. These ''High-Gradient Insulators'' have been experimentally shown to withstand higher voltage gradients than comparable conventional insulators. As a result, they have application to a wide range of high-voltage vacuum systems where compact size is important. This paper describes ongoing research on these structures, as well as the current theoretical understanding driving this work.

  19. The Jumping Ring Experiment

    ERIC Educational Resources Information Center

    Baylie, M.; Ford, P. J.; Mathlin, G. P.; Palmer, C.

    2009-01-01

    The jumping ring experiment has become central to liquid nitrogen shows given as part of the outreach and open day activities carried out within the University of Bath. The basic principles of the experiment are described as well as the effect of changing the geometry of the rings and their metallurgical state. In general, aluminium rings are…

  20. Rings Around Uranus

    ERIC Educational Resources Information Center

    Maran, Stephen P.

    1977-01-01

    Events leading up to the discovery of the rings of Uranus are described. The methods used and the logic behind the methods are explained. Data collected to prove the existence of the rings are outlined and theories concerning the presence of planetary rings are presented. (AJ)

  1. 'Insulator bodies' are aggregates of proteins but not of insulators.

    PubMed

    Golovnin, Anton; Melnikova, Larisa; Volkov, Ilya; Kostuchenko, Margarita; Galkin, Alexander V; Georgiev, Pavel

    2008-05-01

    Chromatin insulators are thought to restrict the action of enhancers and silencers. The best-known insulators in Drosophila require proteins such as Suppressor of Hairy wing (Su(Hw)) and Modifier of mdg4 (Mod(mdg4)) to be functional. The insulator-related proteins apparently colocalize as nuclear speckles in immunostained cells. It has been asserted that these speckles are 'insulator bodies' of many Su(Hw)-insulator DNA sites held together by associated proteins, including Mod(mdg4). As we show here using flies, larvae and S2 cells, a mutant Mod(mdg4) protein devoid of the Q-rich domain supports the function of Su(Hw)-dependent insulators and efficiently binds to correct insulator sites on the chromosome, but does not form or enter the Su(Hw)-marked nuclear speckles; conversely, the latter accumulate another (C-truncated) Mod(mdg4) mutant that cannot interact with Su(Hw) or with the genuine insulators. Hence, it is not the functional genomic insulators but rather aggregated proteins that make the so-called 'insulator bodies'.

  2. Compact vacuum insulation embodiments

    DOEpatents

    Benson, David K.; Potter, Thomas F.

    1992-01-01

    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.

  3. Compact vacuum insulation

    DOEpatents

    Benson, David K.; Potter, Thomas F.

    1993-01-01

    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.

  4. Insulated pipe clamp design

    SciTech Connect

    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. Installing fiber insulation

    NASA Technical Reports Server (NTRS)

    Wang, D. S.; Warren, A. D. (Inventor)

    1980-01-01

    A method for installing fragile, high temperature insulation batting in an elongated cavity or in a resilient wire sleeve to form a resilient seal. The batting is preformed to rough dimensions and wrapped in a plastic film, the film being of a material which is fugitive at a high temperature. The film is heat sealed and trimmed to form a snugly fit skin which overlaps at least at one end to permit attachment of a pull cord. The film absorbs the tensile force of pulling the film enclosed batting through the cavity or wire mesh sleeve and is subsequently driven off by high temperature baking, leaving only the insulation in the cavity or wire mesh sleeve.

  6. Compact vacuum insulation embodiments

    DOEpatents

    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.

  7. Compact vacuum insulation

    DOEpatents

    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.

  8. Saturn's largest ring.

    PubMed

    Verbiscer, Anne J; Skrutskie, Michael F; Hamilton, Douglas P

    2009-10-22

    Most planetary rings in the Solar System lie within a few radii of their host body, because at these distances gravitational accelerations inhibit satellite formation. The best known exceptions are Jupiter's gossamer rings and Saturn's E ring, broad sheets of dust that extend outward until they fade from view at five to ten planetary radii. Source satellites continuously supply the dust, which is subsequently lost in collisions or by radial transport. Here we report that Saturn has an enormous ring associated with its outer moon Phoebe, extending from at least 128R(S) to 207R(S) (Saturn's radius R(S) is 60,330 km). The ring's vertical thickness of 40R(S) matches the range of vertical motion of Phoebe along its orbit. Dynamical considerations argue that these ring particles span the Saturnian system from the main rings to the edges of interplanetary space. The ring's normal optical depth of approximately 2 x 10(-8) is comparable to that of Jupiter's faintest gossamer ring, although its particle number density is several hundred times smaller. Repeated impacts on Phoebe, from both interplanetary and circumplanetary particle populations, probably keep the ring populated with material. Ring particles smaller than centimetres in size slowly migrate inward and many of them ultimately strike the dark leading face of Iapetus.

  9. Pourable Foam Insulation

    NASA Technical Reports Server (NTRS)

    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.

  10. Repairing Foam Insulation

    NASA Technical Reports Server (NTRS)

    Corbin, J.; Buras, D.

    1986-01-01

    Large holes in polyurethane foam insulation repaired reliably by simple method. Little skill needed to apply method, used for overhead repairs as well as for those in other orientations. Plug positioned in hole to be filled and held in place with mounting fixture. Fresh liquid foam injected through plug to bond it in place. As foam cures and expands, it displaces plug outward. Protrusion later removed.

  11. Gas filled panel insulation

    DOEpatents

    Griffith, Brent T.; Arasteh, Dariush K.; Selkowitz, Stephen E.

    1993-01-01

    A structural or flexible highly insulative panel which may be translucent, is formed from multi-layer polymeric material in the form of an envelope surrounding a baffle. The baffle is designed so as to minimize heat transfer across the panel, by using material which forms substantially closed spaces to suppress convection of the low conductivity gas fill. At least a portion of the baffle carries a low emissivity surface for suppression of infrared radiation.

  12. Gas filled panel insulation

    DOEpatents

    Griffith, B.T.; Arasteh, D.K.; Selkowitz, S.E.

    1993-12-14

    A structural or flexible highly insulative panel which may be translucent, is formed from multi-layer polymeric material in the form of an envelope surrounding a baffle. The baffle is designed so as to minimize heat transfer across the panel, by using material which forms substantially closed spaces to suppress convection of the low conductivity gas fill. At least a portion of the baffle carries a low emissivity surface for suppression of infrared radiation. 18 figures.

  13. Glass fiber insulation

    SciTech Connect

    Griffith, E.J.; Ngo, T.M.

    1993-06-29

    A composition for a glass fiber insulation is described comprising a loose mat of glass fibers having at least a portion of the surface coated with a water insoluble, non-hygroscopic, amorphous aluminum phosphate polymer having a molar ratio of Al[sub 2]O[sub 3] to P[sub 2]O[sub 5] of less than 1 and providing a substantial thermal resistance.

  14. Thermal insulated building slab

    SciTech Connect

    Hacker, J. H.

    1985-06-25

    A thermally insulated building foundation structure comprising a monolithic poured concrete foundation extending about the perimeter of a building site and having a plurality of elongate straight sides with flat, vertical outside surfaces with lower portions below the surface of the ground and upper portions above the surface of the ground and having flat, horizontal top surfaces, a thermal insulating girdle about the perimeter of the upper portion of the foundation comprised of a plurality of elongate straight horizontal channel sections in end to end relationship and having vertical outside walls defining the outside surface of said upper portion of the foundation, horizontal top walls defining the outer portion of said top surface of the foundation, horizontal bottom walls and upper and lower flanges on inner edges of the top and bottom walls and cores of thermal insulating material filling the channel sections; and a plurality of anchor units spaced about the girdle and having inner deadman portions set in the concrete and outer portions in secure engagement with the flanges of the channel sections.

  15. Thermal Insulation Test Apparatuses

    NASA Technical Reports Server (NTRS)

    Berman, Brion

    2005-01-01

    The National Aeronautics and Space Administration (NASA) seeks to license its Thermal Insulation Test Apparatuses. Designed by the Cryogenics Test Laboratory at the John F. Kennedy Space Center (KSC) in Florida, these patented technologies (U.S. Patent Numbers: Cryostat 1 - 6,742,926, Cryostat 2 - 6,487,866, and Cryostat 4 - 6,824,306) allow manufacturers to fabricate and test cryogenic insulation at their production and/or laboratory facilities. These new inventions allow for the thermal performance characterization of cylindrical and flat specimens (e.g., bulk-fill, flat-panel, multilayer, or continuously rolled) over the full range of pressures, from high vacuum to no vacuum, and over the full range of temperatures from 77K to 300K. In today's world, efficient, low-maintenance, low-temperature refrigeration is taking a more significant role, from the food industry, transportation, energy, and medical applications to the Space Shuttle. Most countries (including the United States) have laws requiring commercially available insulation materials to be tested and rated by an accepted methodology. The new Cryostat methods go beyond the formal capabilities of the ASTM methods to provide testing for real systems, including full-temperature differences plus full-range vacuum conditions.

  16. Weyl Mott Insulator.

    PubMed

    Morimoto, Takahiro; Nagaosa, Naoto

    2016-01-01

    Relativistic Weyl fermion (WF) often appears in the band structure of three dimensional magnetic materials and acts as a source or sink of the Berry curvature, i.e., the (anti-)monopole. It has been believed that the WFs are stable due to their topological indices except when two Weyl fermions of opposite chiralities annihilate pairwise. Here, we theoretically show for a model including the electron-electron interaction that the Mott gap opens for each WF without violating the topological stability, leading to a topological Mott insulator dubbed Weyl Mott insulator (WMI). This WMI is characterized by several novel features such as (i) energy gaps in the angle-resolved photo-emission spectroscopy (ARPES) and the optical conductivity, (ii) the nonvanishing Hall conductance, and (iii) the Fermi arc on the surface with the penetration depth diverging as approaching to the momentum at which the Weyl point is projected. Experimental detection of the WMI by distinguishing from conventional Mott insulators is discussed with possible relevance to pyrochlore iridates. PMID:26822023

  17. Weyl Mott Insulator

    PubMed Central

    Morimoto, Takahiro; Nagaosa, Naoto

    2016-01-01

    Relativistic Weyl fermion (WF) often appears in the band structure of three dimensional magnetic materials and acts as a source or sink of the Berry curvature, i.e., the (anti-)monopole. It has been believed that the WFs are stable due to their topological indices except when two Weyl fermions of opposite chiralities annihilate pairwise. Here, we theoretically show for a model including the electron-electron interaction that the Mott gap opens for each WF without violating the topological stability, leading to a topological Mott insulator dubbed Weyl Mott insulator (WMI). This WMI is characterized by several novel features such as (i) energy gaps in the angle-resolved photo-emission spectroscopy (ARPES) and the optical conductivity, (ii) the nonvanishing Hall conductance, and (iii) the Fermi arc on the surface with the penetration depth diverging as approaching to the momentum at which the Weyl point is projected. Experimental detection of the WMI by distinguishing from conventional Mott insulators is discussed with possible relevance to pyrochlore iridates. PMID:26822023

  18. Improved DC Gun Insulator

    SciTech Connect

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

    2009-05-01

    Many user facilities such as synchrotron light sources and free electron lasers require accelerating structures that support electric fields of 10-100 MV/m, especially at the start of the accelerator chain where ceramic insulators are used for very high gradient DC guns. These insulators are difficult to manufacture, require long commissioning times, and have poor reliability, in part because energetic electrons bury themselves in the ceramic, creating a buildup of charge and causing eventual puncture. A novel ceramic manufacturing process is proposed. It will incorporate bulk resistivity in the region where it is needed to bleed off accumulated charge caused by highly energetic electrons. This process will be optimized to provide an appropriate gradient in bulk resistivity from the vacuum side to the air side of the HV standoff ceramic cylinder. A computer model will be used to determine the optimum cylinder dimensions and required resistivity gradient for an example RF gun application. A ceramic material example with resistivity gradient appropriate for use as a DC gun insulator will be fabricated by glazing using doping compounds and tested.

  19. Ultraflexible and ultrathin polymeric gate insulator for 2 V organic transistor circuits

    NASA Astrophysics Data System (ADS)

    Kondo, Masaya; Uemura, Takafumi; Matsumoto, Takafumi; Araki, Teppei; Yoshimoto, Shusuke; Sekitani, Tsuyoshi

    2016-06-01

    We have developed a high-yield process for fabricating organic transistors with ultraflexible and ultrathin polymeric (parylene) insulators. In a top-contact bottom-gate configuration, an oxygen plasma treatment for a Au gate surface before parylene deposition significantly improved the yield of transistors, enabling the parylene thickness to be reduced to 18 nm. Taking full advantage of the ultraflexible and ultrathin insulator, we have demonstrated 2 V ring oscillator circuits, where the yield was 97% for 360 transistors inside the area of 7 × 7 cm2. The highly reliable ultrathin insulator is useful for large-area circuits with low-voltage organic transistors.

  20. Insulator - Insulator Contact Charging as a Function of Pressure

    NASA Technical Reports Server (NTRS)

    Hogue, Michael D.; Mucciolo, E. R.; Calle, C. I.

    2006-01-01

    Metal - metal and metal - insulator contact or triboelectric charging are well known phenomena with good theoretical understanding of the charge exchange mechanism. However, insulator - insulator charging is not as well understood. Theoretical and experimental research has been performed that shows that the surface charge on an insulator after triboelectric charging with another insulator is rapidly dissipated with lowered atmospheric pressure. This pressure discharge is consistent with surface ions being evaporated off the surface once their vapor pressure is attained. A two-phase equilibrium model based on an ideal gas of singly charged ions in equilibrium with a submonolayer adsorbed film was developed to describe the pressure dependence of the surface charge on an insulator. The resulting charge density equation is an electrostatic version of the Langmuir isotherm.

  1. Of Rings and Volcanoes

    NASA Astrophysics Data System (ADS)

    2002-01-01

    Office National d'Etudes et de Recherches Aérospatiales (ONERA) , Laboratoire d'Astrophysique de Grenoble (LAOG) and the DESPA and DASGAL laboratories of the Observatoire de Paris in France, in collaboration with ESO. The CONICA infra-red camera was built, under an ESO contract, by the Max-Planck-Institut für Astronomie (MPIA) (Heidelberg) and the Max-Planck Institut für Extraterrestrische Physik (MPE) (Garching) in Germany, in collaboration with ESO. Saturn - Lord of the rings ESO PR Photo 04a/02 ESO PR Photo 04a/02 [Preview - JPEG: 460 x 400 pix - 54k] [Normal - JPEG: 1034 x 800 pix - 200k] Caption : PR Photo 04a/02 shows the giant planet Saturn, as observed with the VLT NAOS-CONICA Adaptive Optics instrument on December 8, 2001; the distance was 1209 million km. It is a composite of exposures in two near-infrared wavebands (H and K) and displays well the intricate, banded structure of the planetary atmosphere and the rings. Note also the dark spot at the south pole at the bottom of the image. One of the moons, Tethys, is visible as a small point of light below the planet. It was used to guide the telescope and to perform the adaptive optics "refocussing" for this observation. More details in the text. Technical information about this photo is available below. This NAOS/CONICA image of Saturn ( PR Photo 04a/02 ), the second-largest planet in the solar system, was obtained at a time when Saturn was close to summer solstice in the southern hemisphere. At this moment, the tilt of the rings was about as large as it can be, allowing the best possible view of the planet's South Pole. That area was on Saturn's night side in 1982 and could therefore not be photographed during the Voyager encounter. The dark spot close to the South Pole is a remarkable structure that measures approximately 300 km across. It was only recently observed in visible light from the ground with a telescope at the Pic du Midi Observatory in the Pyrenees (France) - this is the first infrared image to

  2. Topological insulators and superconductors

    NASA Astrophysics Data System (ADS)

    Teo, Jeffrey C. Y.

    We study theoretical properties of robust low energy electronic excitations associated with topological insulators and superconductors. The bulk materials are described by non-interacting single particle band Hamiltonians with a finite excitation gap. Their topological phases are classifed according to symmetries and dimensions, characterized by discrete bulk invariants, and correspond to topologically protected gapless excitations bounded to boundaries, interfaces or other kinds of defects. In particular, we study the metallic surface states of the three dimensional topological insulator Bi1-- xSbx, critical edge transport behavior of quantum spin Hall insulators (QSHI) using point contact geometry, Majorana bound states in three dimensions and their resemblance to Ising statistics, and various gapless modes accompanying topological defects in insulators and superconductors. We illustrate the topological phase of Bi1-- xSbx by calculating its surface energy spectrum numerically from a previously proposed tight binding model. An odd number of surface Dirac cones occupy the surface Brillouin zone and exhibit the strong topological nature of the material. We investigate the critical conductance behavior of a point contact in QSHI using a spinful Luttinger liquid description along the edges. For weak interactions, a novel intermediate fixed point controls the pinch-off transition, and the universal crossover scaling function of conductance is extracted from the solvable limits for the Luttinger parameter g = 1 -- epsilon, g = 1/2 + epsilon, and g = 1/ 3 . Majorana fermions are studied as zero energy quasiparticle excitations associated with pointlike topological defects in 3D superconductors. The low energy modes are described phenomenologically in a Dirac-type Bogoliubov de Gennes (BdG) framework, and the Majorana bound states are shown to exhibit Ising non-Abelian statistics despite living in (3 + 1) dimensions. In particular, novel braidless operations are shown to

  3. Möbius molecules and fragile Mott insulators

    NASA Astrophysics Data System (ADS)

    Muechler, Lukas; Maciejko, Joseph; Neupert, Titus; Car, Roberto

    2014-12-01

    Motivated by the concept of Möbius aromatics in organic chemistry, we extend the recently introduced concept of fragile Mott insulators (FMI) to ring-shaped molecules with repulsive Hubbard interactions threaded by a half-quantum of magnetic flux (h c /2 e ) . In this context, an FMI is the insulating ground state of a finite-size molecule that cannot be adiabatically connected to a single Slater determinant, i.e., to a band insulator, provided that time-reversal and lattice translation symmetries are preserved. Based on exact numerical diagonalization for finite Hubbard interaction strength U and existing Bethe-ansatz studies of the one-dimensional Hubbard model in the large-U limit, we establish a duality between Hubbard molecules with 4 n and 4 n +2 sites, with n integer. A molecule with 4 n sites is an FMI in the absence of flux but becomes a band insulator in the presence of a half-quantum of flux, while a molecule with 4 n +2 sites is a band insulator in the absence of flux but becomes an FMI in the presence of a half-quantum of flux. Including next-nearest-neighbor hoppings gives rise to new FMI states that belong to multidimensional irreducible representations of the molecular point group, giving rise to a rich phase diagram.

  4. Möbius molecules and fragile Mott insulators

    NASA Astrophysics Data System (ADS)

    Muechler, Lukas; Maciejko, Joseph; Neupert, Titus; Car, Roberto

    2015-03-01

    Motivated by the concept of Möbius aromatics in organic chemistry, we extend the recently introduced concept of fragile Mott insulators (FMI) to ring-shaped molecules with repulsive Hubbard interactions threaded by a half-quantum of magnetic flux (hc / 2 e). In this context, a FMI is the insulating ground state of a finite-size molecule that cannot be adiabatically connected to a single Slater determinant, i.e., to a band insulator, provided that time-reversal and lattice translation symmetries are preserved. Based on exact numerical diagonalization for finite Hubbard interaction strength U and existing Bethe-ansatz studies of the one-dimensional Hubbard model in the large- U limit, we establish a duality between Hubbard molecules with 4 n and 4 n + 2 sites, with n integer. A molecule with 4 n sites is an FMI in the absence of flux but becomes a band insulator in the presence of a half-quantum of flux, while a molecule with 4 n + 2 sites is a band insulator in the absence of flux but becomes an FMI in the presence of a half-quantum of flux. Including next-nearest-neighbor-hoppings gives rise to new FMI states that belong to multidimensional irreducible representations of the molecular point group, giving rise to a rich phase diagram. Reference: arXiv:1409.6732

  5. Dust and Planetary Rings

    NASA Astrophysics Data System (ADS)

    Siddiqui, Muddassir

    ABSTRACT Space is not empty it has comic radiations (CMBR), dust etc. Cosmic dust is that type of dust which is composed of particles in space which vary from few molecules to 0.1micro metres in size. This type of dust is made up of heavier atoms born in the heart of stars and supernova. Mainly it contains dust grains and when these dust grains starts compacting then it turns to dense clouds, planetary ring dust and circumstellar dust. Dust grains are mainly silicate particles. Dust plays a major role in our solar system, for example in zodiacal light, Saturn's B ring spokes, planetary rings at Jovian planets and comets. Observations and measurements of cosmic dust in different regions of universe provide an important insight into the Universe's recycling processes. Astronomers consider dust in its most recycled state. Cosmic dust have radiative properties by which they can be detected. Cosmic dusts are classified as intergalactic dusts, interstellar dusts and planetary rings. A planetary ring is a ring of cosmic dust and other small particles orbiting around a planet in flat disc shape. All of the Jovian planets in our solar system have rings. But the most notable one is the Saturn's ring which is the brightest one. In March 2008 a report suggested that the Saturn's moon Rhea may have its own tenuous ring system. The ring swirling around Saturn consists of chunks of ice and dust. Most rings were thought to be unstable and to dissipate over course of tens or hundreds of millions of years but it now appears that Saturn's rings might be older than that. The dust particles in the ring collide with each other and are subjected to forces other than gravity of its own planet. Such collisions and extra forces tend to spread out the rings. Pluto is not known to have any ring system but some Astronomers believe that New Horizons probe might find a ring system when it visits in 2015.It is also predicted that Phobos, a moon of Mars will break up and form into a planetary ring

  6. Manifold Insulation for Solar Collectors

    NASA Technical Reports Server (NTRS)

    1982-01-01

    Results of computer analysis of effects of various manifold insulation detailed in 23-page report show that if fluid is distributed to and gathered from array of solar collectors by external rather than internal manifold, effectiveness of manifold insulation has major influence on efficiency. Report describes required input data and presents equations that govern computer model. Provides graphs comparing collector efficiencies for representative manifold sizes and insulations.

  7. Solid rocket motor internal insulation

    NASA Technical Reports Server (NTRS)

    Twichell, S. E. (Editor); Keller, R. B., Jr.

    1976-01-01

    Internal insulation in a solid rocket motor is defined as a layer of heat barrier material placed between the internal surface of the case propellant. The primary purpose is to prevent the case from reaching temperatures that endanger its structural integrity. Secondary functions of the insulation are listed and guidelines for avoiding critical problems in the development of internal insulation for rocket motors are presented.

  8. Magnetic insulation for plasma propulsion

    NASA Technical Reports Server (NTRS)

    Gonzalez, Dora E.

    1990-01-01

    The design parameters of effective magnetic insulation for plasma engines are discussed. An experimental model used to demonstrate the process of plasma acceleration and magnetic insulation is considered which consists of a copper strap that is wound around a glass tube and connected to a capacitor. In order to adequately model the magnetic insulation mechanisms, a computer algorithm is developed. Plasma engines, with their efficient utilization of the propellant mass, are expected to provide the next-generation advanced propulsion systems.

  9. Insulating Cryogenic Pipes With Frost

    NASA Technical Reports Server (NTRS)

    Stephenson, J. G.; Bova, J. A.

    1985-01-01

    Crystallized water vapor fills voids in pipe insulation. Small, carefully controlled amount of water vapor introduced into dry nitrogen gas before it enters aft fuselage. Vapor freezes on pipes, filling cracks in insulation. Ice prevents gaseous nitrogen from condensing on pipes and dripping on structure, in addition to helping to insulate all parts. Industrial applications include large refrigeration plants or facilities that use cryogenic liquids.

  10. On multiple Einstein rings

    NASA Astrophysics Data System (ADS)

    Werner, M. C.; An, J.; Evans, N. W.

    2008-12-01

    A number of recent surveys for gravitational lenses have found examples of double Einstein rings. Here, we analytically investigate the occurrence of multiple Einstein rings. We prove, under very general assumptions, that at the most one Einstein ring can arise from a mass distribution in a single plane lensing a single background source. Two or more Einstein rings can therefore only occur in multiplane lensing. Surprisingly, we show that it is possible for a single source to produce more than one Einstein ring. If two point masses, or two isothermal spheres, in different planes are aligned with observer and source on the optical axis, we show that there are up to three Einstein rings. We also discuss the image morphologies for these two models if axisymmetry is broken, and give the first instances of magnification invariants in the case of two-lens planes.

  11. DEGRADATION OF MAGNET EPOXY AT NSLS X-RAY RING.

    SciTech Connect

    HU,J.P.; ZHONG,Z.; HAAS,E.; HULBERT,S.; HUBBARD,R.

    2004-05-24

    Epoxy resin degradation was analyzed for NSLS X-ring magnets after two decades of 2.58-2.8 GeV continuous electron-beam operation, based on results obtained from thermoluminescent dosimeters irradiated along the NSLS ring and epoxy samples irradiated at the beamline target location. A Monte Carlo-based particle transport code, MCNP, was utilized to verify the dose from synchrotron radiation distributed along the axial- and transverse-direction in a ring model, which simulates the geometry of a ring quadrupole magnet and its central vacuum chamber downstream of the bending-magnet photon ports. The actual life expectancy of thoroughly vacuum baked-and-cured epoxy resin was estimated from radiation tests on similar polymeric materials using a radiation source developed for electrical insulation and mechanical structure studies.

  12. Radioactive gold ring dermatitis

    SciTech Connect

    Miller, R.A.; Aldrich, J.E. )

    1990-08-01

    A superficial squamous cell carcinoma developed in a woman who wore a radioactive gold ring for more than 30 years. Only part of the ring was radioactive. Radiation dose measurements indicated that the dose to basal skin layer was 2.4 Gy (240 rad) per week. If it is assumed that the woman continually wore her wedding ring for 37 years since purchase, she would have received a maximum dose of approximately 4600 Gy.

  13. Temperatures of Saturn's rings.

    NASA Technical Reports Server (NTRS)

    Murphy, R. E.

    1973-01-01

    The 20-micron brightness temperatures of the rings were determined using the 224-cm telescope of the Mauna Kea Observatory, and the standard University of Hawaii radiometer with a 17- to 25-micron filter. The observations were made on the nights of Aug. 20 and 21, and Sept. 26 and 27, 1972. The brightness temperatures of the A, B, and C rings are, respectively, 89 plus or minus 3 K, 94 plus or minus 2 K, and 89 plus or minus 4 K. A possible explanation of the relatively high temperature of the C ring is that Saturn has radiation belts and the inner ring is heated by particle bombardment.

  14. Insulator Protein Helps Organize the Gaps in the Axon's Insulation.

    PubMed

    Robinson, Richard

    2015-01-01

    The protein P0 has long been known to play a crucial role in holding together the myelin sheath that insulates peripheral nerves. A new study reveals that P0 is also important for organizing the nodes of Ranvier that occupy the gaps in the insulation. Read the Research Article.

  15. Insulating materials and insulation: a bibliography, No. A 535

    SciTech Connect

    Vance, M.

    1981-01-01

    A bibliography is presented covering the subjects of: (1) insulation materials (52 references); and (2) insulation (325 references). Journal articles, books, magazines, and reports are cited. Alphabetical listings are given of a title index, subject index, and author index. In the case of book references, prices are given. (MJJ)

  16. Ring Around a Galaxy

    NASA Technical Reports Server (NTRS)

    1999-01-01

    Space Telescope Science Institute astronomers are giving the public chances to decide where to aim NASA's Hubble Space Telescope. Guided by 8,000 Internet voters, Hubble has already been used to take a close-up, multi-color picture of the most popular object from a list of candidates, the extraordinary 'polar-ring' galaxy NGC 4650A. Located about 130 million light-years away, NGC 4650A is one of only 100 known polar-ring galaxies. Their unusual disk-ring structure is not yet understood fully. One possibility is that polar rings are the remnants of colossal collisions between two galaxies sometime in the distant past, probably at least 1 billion years ago. What is left of one galaxy has become the rotating inner disk of old red stars in the center. Meanwhile, another smaller galaxy which ventured too close was probably severely damaged or destroyed. The bright bluish clumps, which are especially prominent in the outer parts of the ring, are regions containing luminous young stars, examples of stellar rebirth from the remnants of an ancient galactic disaster. The polar ring appears to be highly distorted. No regular spiral pattern stands out in the main part of the ring, and the presence of young stars below the main ring on one side and above on the other shows that the ring is warped and does not lie in one plane. Determining the typical ages of the stars in the polar ring is an initial goal of our Polar Ring Science Team that can provide a clue to the evolution of this unusual galaxy. The HST exposures were acquired by the Hubble Heritage Team, consisting of Keith Noll, Howard Bond, Carol Christian, Jayanne English, Lisa Frattare, Forrest Hamilton, Anne Kinney and Zolt Levay, and guest collaborators Jay Gallagher (University of Wisconsin-Madison), Lynn Matthews (National Radio Astronomy Observatory-Charlottesville), and Linda Sparke (University of Wisconsin-Madison).

  17. Model Fractional Chern Insulators.

    PubMed

    Behrmann, Jörg; Liu, Zhao; Bergholtz, Emil J

    2016-05-27

    We devise local lattice models whose ground states are model fractional Chern insulators-Abelian and non-Abelian topologically ordered states characterized by exact ground state degeneracies at any finite size and infinite entanglement gaps. Most saliently, we construct exact parent Hamiltonians for two distinct families of bosonic lattice generalizations of the Z_{k} parafermion quantum Hall states: (i) color-entangled fractional Chern insulators at band filling fractions ν=k/(C+1) and (ii) nematic states at ν=k/2, where C is the Chern number of the lowest band. In spite of a fluctuating Berry curvature, our construction is partially frustration free: the ground states reside entirely within the lowest band and exactly minimize a local (k+1) body repulsion term by term. In addition to providing the first known models hosting intriguing states such as higher Chern number generalizations of the Fibonacci anyon quantum Hall states, the remarkable stability and finite-size properties make our models particularly well suited for the study of novel phenomena involving, e.g., twist defects and proximity induced superconductivity, as well as being a guide for designing experiments.

  18. Compact vacuum insulation

    DOEpatents

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

    1992-10-27

    Improved compact insulation panel is provided which is comprised of two adjacent metal sheets spaced close together with a plurality of spherical, or other discretely shaped, glass or ceramic beads optimally positioned between the sheets to provide support and maintain the spacing between the metal sheets when the gases there between are evacuated to form a vacuum. These spherical glass beads provide the maximum support while minimizing thermal conductance. In its preferred embodiment; these two metal sheets are textured with ribs or concave protrusions in conjunction with the glass beads to maximize the structural integrity of the panels while increasing the spacing between beads, thereby reducing the number of beads and the number of thermal conduction paths. Glass or porcelain-enameled liners in combination with the glass spacers and metal sidewalls effectively decrease thermal conductivity, and various laminates, including wood, porcelain-enameled metal, and others effectively increase the strength and insulation capabilities of the panels. Also, a metal web is provided to hold the spacers in place, and strategic grooves are shown to accommodate expansion and contraction or shaping of the panels. 35 figs.

  19. Compact vacuum insulation

    DOEpatents

    Benson, David K.; Potter, Thomas F.

    1992-01-01

    Improved compact insulation panel is provided which is comprised of two adjacent metal sheets spaced close together with a plurality of spherical, or other discretely shaped, glass or ceramic beads optimally positioned between the sheets to provide support and maintain the spacing between the metal sheets when the gases therebetween are evacuated to form a vacuum. These spherical glass beads provide the maximum support while minimizing thermal conductance. In its preferred embodiment; these two metal sheets are textured with ribs or concave protrusions in conjunction with the glass beads to maximize the structural integrity of the panels while increasing the spacing between beads, thereby reducing the number of beads and the number of thermal conduction paths. Glass or porcelain-enameled liners in combination with the glass spacers and metal sidewalls effectively decrease thermal conductivity, and variious laminates, including wood, porcelain-enameled metal, and others effectively increase the strength and insulation capabilities of the panels. Also, a metal web is provided to hold the spacers in place, and strategic grooves are shown to accommodate expansion and contraction or shaping of the panels.

  20. Model Fractional Chern Insulators.

    PubMed

    Behrmann, Jörg; Liu, Zhao; Bergholtz, Emil J

    2016-05-27

    We devise local lattice models whose ground states are model fractional Chern insulators-Abelian and non-Abelian topologically ordered states characterized by exact ground state degeneracies at any finite size and infinite entanglement gaps. Most saliently, we construct exact parent Hamiltonians for two distinct families of bosonic lattice generalizations of the Z_{k} parafermion quantum Hall states: (i) color-entangled fractional Chern insulators at band filling fractions ν=k/(C+1) and (ii) nematic states at ν=k/2, where C is the Chern number of the lowest band. In spite of a fluctuating Berry curvature, our construction is partially frustration free: the ground states reside entirely within the lowest band and exactly minimize a local (k+1) body repulsion term by term. In addition to providing the first known models hosting intriguing states such as higher Chern number generalizations of the Fibonacci anyon quantum Hall states, the remarkable stability and finite-size properties make our models particularly well suited for the study of novel phenomena involving, e.g., twist defects and proximity induced superconductivity, as well as being a guide for designing experiments. PMID:27284668

  1. Wall Insulation; BTS Technology Fact Sheet

    SciTech Connect

    Southface Energy Institute; Tromly, K.

    2000-11-07

    Properly sealed, moisture-protected, and insulated walls help increase comfort, reduce noise, and save on energy costs. This fact sheet addresses these topics plus advanced framing techniques, insulation types, wall sheathings, and steps for effective wall construction and insulation.

  2. Electrical wire insulation and electromagnetic coil

    DOEpatents

    Bich, George J.; Gupta, Tapan K.

    1984-01-01

    An electromagnetic coil for high temperature and high radiation application in which glass is used to insulate the electrical wire. A process for applying the insulation to the wire is disclosed which results in improved insulation properties.

  3. Smoke Ring Physics

    ERIC Educational Resources Information Center

    Huggins, Elisha

    2011-01-01

    The behavior of smoke rings, tornados, and quantized vortex rings in superfluid helium has many features in common. These features can be described by the same mathematics we use when introducing Ampere's law in an introductory physics course. We discuss these common features. (Contains 7 figures.)

  4. Lower esophageal ring (Schatzki)

    MedlinePlus

    ... narrowed area to stretch the ring. Sometimes, a balloon is placed in the area and inflated, to help widen the ring. Outlook (Prognosis) Swallowing problems may return. You may need repeat treatment. When to Contact a Medical Professional Call your health care provider if you ...

  5. EBT ring physics

    SciTech Connect

    Uckan, N.A.

    1980-04-01

    This workshop attempted to evaluate the status of the current experimental and theoretical understanding of hot electron ring properties. The dominant physical processes that influence ring formation, scaling, and their optimal behavior are also studied. Separate abstracts were prepared for each of the 27 included papers. (MOW)

  6. Contactless Magnetic Slip Ring

    NASA Technical Reports Server (NTRS)

    Kumagai, Hiroyuki (Inventor); Deardon, Joe D. (Inventor)

    1997-01-01

    A contactless magnetic slip ring is disclosed having a primary coil and a secondary coil. The primary and secondary coils are preferably magnetically coupled together, in a highly reliable efficient manner, by a magnetic layered core. One of the secondary and primary coils is rotatable and the contactless magnetic slip ring provides a substantially constant output.

  7. Smoke Ring Physics

    NASA Astrophysics Data System (ADS)

    Huggins, Elisha

    2011-11-01

    The behavior of smoke rings, tornados, and quantized vortex rings in superfluid helium has many features in common. These features can be described by the same mathematics we use when introducing Ampère's law in an introductory physics course. We discuss these common features.

  8. Plastic Materials for Insulating Applications.

    ERIC Educational Resources Information Center

    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. No insulating effect of obesity.

    PubMed

    Fischer, Alexander W; Csikasz, Robert I; von Essen, Gabriella; Cannon, Barbara; Nedergaard, Jan

    2016-07-01

    The development of obesity may be aggravated if obesity itself insulates against heat loss and thus diminishes the amount of food burnt for body temperature control. This would be particularly important under normal laboratory conditions where mice experience a chronic cold stress (at ≈20°C). We used Scholander plots (energy expenditure plotted against ambient temperature) to examine the insulation (thermal conductance) of mice, defined as the inverse of the slope of the Scholander curve at subthermoneutral temperatures. We verified the method by demonstrating that shaved mice possessed only half the insulation of nonshaved mice. We examined a series of obesity models [mice fed high-fat diets and kept at different temperatures, classical diet-induced obese mice, ob/ob mice, and obesity-prone (C57BL/6) vs. obesity-resistant (129S) mice]. We found that neither acclimation temperature nor any kind or degree of obesity affected the thermal insulation of the mice when analyzed at the whole mouse level or as energy expenditure per lean weight. Calculation per body weight erroneously implied increased insulation in obese mice. We conclude that, in contrast to what would be expected, obesity of any kind does not increase thermal insulation in mice, and therefore, it does not in itself aggravate the development of obesity. It may be discussed as to what degree of effect excess adipose tissue has on insulation in humans and especially whether significant metabolic effects are associated with insulation in humans. PMID:27189935

  10. Washing Off Polyurethane Foam Insulation

    NASA Technical Reports Server (NTRS)

    Burley, Richard K.; Fogel, Irving

    1990-01-01

    Jet of hot water removes material quickly and safely. Simple, environmentally sound technique found to remove polyurethane foam insulation from metal parts. Developed for (but not limited to) use during rebuilding of fuel system of Space Shuttle main engine, during which insulation must be removed for penetrant inspection of metal parts.

  11. Tailorable Advanced Blanket Insulation (TABI)

    NASA Technical Reports Server (NTRS)

    Sawko, Paul M.; Goldstein, Howard E.

    1987-01-01

    Single layer and multilayer insulating blankets for high-temperature service fabricated without sewing. TABI woven fabric made of aluminoborosilicate. Triangular-cross-section flutes of core filled with silica batting. Flexible blanket formed into curved shapes, providing high-temperature and high-heat-flux insulation.

  12. No insulating effect of obesity.

    PubMed

    Fischer, Alexander W; Csikasz, Robert I; von Essen, Gabriella; Cannon, Barbara; Nedergaard, Jan

    2016-07-01

    The development of obesity may be aggravated if obesity itself insulates against heat loss and thus diminishes the amount of food burnt for body temperature control. This would be particularly important under normal laboratory conditions where mice experience a chronic cold stress (at ≈20°C). We used Scholander plots (energy expenditure plotted against ambient temperature) to examine the insulation (thermal conductance) of mice, defined as the inverse of the slope of the Scholander curve at subthermoneutral temperatures. We verified the method by demonstrating that shaved mice possessed only half the insulation of nonshaved mice. We examined a series of obesity models [mice fed high-fat diets and kept at different temperatures, classical diet-induced obese mice, ob/ob mice, and obesity-prone (C57BL/6) vs. obesity-resistant (129S) mice]. We found that neither acclimation temperature nor any kind or degree of obesity affected the thermal insulation of the mice when analyzed at the whole mouse level or as energy expenditure per lean weight. Calculation per body weight erroneously implied increased insulation in obese mice. We conclude that, in contrast to what would be expected, obesity of any kind does not increase thermal insulation in mice, and therefore, it does not in itself aggravate the development of obesity. It may be discussed as to what degree of effect excess adipose tissue has on insulation in humans and especially whether significant metabolic effects are associated with insulation in humans.

  13. Jupiter's Gossamer Rings Explained.

    NASA Astrophysics Data System (ADS)

    Hamilton, D. P.

    2003-05-01

    Over the past several years, Galileo measurements and groundbased imaging have drastically improved our knowledge of Jupiter's faint ring system. We now recognize that the ring consists of four components: a main ring 7000km wide, whose inner edge blossoms into a vertically-extended halo, and a pair of more tenuous Gossamer rings, one associated with each of the small moons Thebe and Amalthea. When viewed edge on, the Gossamer rings appear as diaphanous disks whose thicknesses agree with the vertical excursions of the inclined satellites from the equatorial plane. In addition, the brightness of each Gossamer ring drops off sharply outside the satellite orbits. These correlations allowed Burns etal (1999, Science, 284, 1146) to argue convincingly that the satellites act as sources of the dusty ring material. In addition, since most material is seen inside the orbits of the source satellites, an inwardly-acting dissipative force such as Poynting-Robertson drag is implicated. The most serious problem with this simple and elegant picture is that it is unable to explain the existence of a faint swath of material that extends half a jovian radius outward from Thebe. A key constraint is that this material has the same thickness as the rest of the Thebe ring. In this work, we identify the mechanism responsible for the outward extension: it is a shadow resonance, first investigated by Horanyi and Burns (1991, JGR, 96, 19283). When a dust grain enters Jupiter's shadow, photoelectric processes shut down and the grain's electric charge becomes more negative. The electromagnetic forces associated with the varying charge cause periodic oscillations in the orbital eccentricity and semimajor axis as the orbital pericenter precesses. This results in a ring which spreads both inward and outward of its source satellite while preserving its vertical thickness - just as is observed for the Thebe ring. Predictions of the model are: i) gaps of micron-sized material interior to Thebe and

  14. Jupiter's Rings: Sharpest View

    NASA Technical Reports Server (NTRS)

    2007-01-01

    The New Horizons spacecraft took the best images of Jupiter's charcoal-black rings as it approached and then looked back at Jupiter. The top image was taken on approach, showing three well-defined lanes of gravel- to boulder-sized material composing the bulk of the rings, as well as lesser amounts of material between the rings. New Horizons snapped the lower image after it had passed Jupiter on February 28, 2007, and looked back in a direction toward the sun. The image is sharply focused, though it appears fuzzy due to the cloud of dust-sized particles enveloping the rings. The dust is brightly illuminated in the same way the dust on a dirty windshield lights up when you drive toward a 'low' sun. The narrow rings are confined in their orbits by small 'shepherding' moons.

  15. Wedding ring shaped excitation coil

    DOEpatents

    MacLennan, Donald A.; Tsai, Peter

    2001-01-01

    A high frequency inductively coupled electrodeless lamp includes an excitation coil with an effective electrical length which is less than one half wavelength of a driving frequency applied thereto, preferably much less. The driving frequency may be greater than 100 MHz and is preferably as high as 915 MHz. Preferably, the excitation coil is configured as a non-helical, semi-cylindrical conductive surface having less than one turn, in the general shape of a wedding ring. At high frequencies, the current in the coil forms two loops which are spaced apart and parallel to each other. Configured appropriately, the coil approximates a Helmholtz configuration. The lamp preferably utilizes an bulb encased in a reflective ceramic cup with a pre-formed aperture defined therethrough. The ceramic cup may include structural features to aid in alignment and/or a flanged face to aid in thermal management. The lamp head is preferably an integrated lamp head comprising a metal matrix composite surrounding an insulating ceramic with the excitation integrally formed on the ceramic. A novel solid-state oscillator preferably provides RF power to the lamp. The oscillator is a single active element device capable of providing over 70 watts of power at over 70% efficiency.

  16. Anode insulator for electrolytic cell

    SciTech Connect

    Robinson, D.J.

    1986-10-28

    An improved anode insulator is described for use in an electrowinning cell, including spaced anodes each supported by an anode header bar, each having the improved anode insulators disposed thereon for preventing contact with spaced cathodes that are respectively disposed between adjacent anodes, each improved anode insulator comprising: (a) first and second elongated insulating means disposed along intermediate portions of opposite faces of one of the anodes for preventing any contact between the faces of that anode and adjacent cathodes; (b) upper connecting means disposed around the top and side portions of the anode header bar supporting that anode and conforming to the shape of the header bar; and (c) lower connecting means for joining the lower end portions of the first and second elongated insulating means.

  17. Impacting device for testing insulation

    NASA Technical Reports Server (NTRS)

    Redmon, J. W. (Inventor)

    1984-01-01

    An electro-mechanical impacting device for testing the bonding of foam insulation to metal is descirbed. The device lightly impacts foam insulation attached to metal to determine whether the insulation is properly bonded to the metal and to determine the quality of the bond. A force measuring device, preferably a load cell mounted on the impacting device, measures the force of the impact and the duration of the time the hammer head is actually in contact with the insulation. The impactor is designed in the form of a handgun having a driving spring which can propel a plunger forward to cause a hammer head to impact the insulation. The device utilizes a trigger mechanism which provides precise adjustements, allowing fireproof operation.

  18. Topological Insulators from Electronic Superstructures

    NASA Astrophysics Data System (ADS)

    Sugita, Yusuke; Motome, Yukitoshi

    2016-07-01

    The possibility of realizing topological insulators by the spontaneous formation of electronic superstructures is theoretically investigated in a minimal two-orbital model including both the spin-orbit coupling and electron correlations on a triangular lattice. Using the mean-field approximation, we show that the model exhibits several different types of charge-ordered insulators, where the charge disproportionation forms a honeycomb or kagome superstructure. We find that the charge-ordered insulators in the presence of strong spin-orbit coupling can be topological insulators showing quantized spin Hall conductivity. Their band gap is dependent on electron correlations as well as the spin-orbit coupling, and even vanishes while showing the massless Dirac dispersion at the transition to a trivial charge-ordered insulator. Our results suggest a new route to realize and control topological states of quantum matter by the interplay between the spin-orbit coupling and electron correlations.

  19. Hybrid Multifoil Aerogel Thermal Insulation

    NASA Technical Reports Server (NTRS)

    Sakamoto, Jeffrey; Paik, Jong-Ah; Jones, Steven; Nesmith, Bill

    2008-01-01

    This innovation blends the merits of multifoil insulation (MFI) with aerogel-based insulation to develop a highly versatile, ultra-low thermally conductive material called hybrid multifoil aerogel thermal insulation (HyMATI). The density of the opacified aerogel is 240 mg/cm3 and has thermal conductivity in the 20 mW/mK range in high vacuum and 25 mW/mK in 1 atmosphere of gas (such as argon) up to 800 C. It is stable up to 1,000 C. This is equal to commercially available high-temperature thermal insulation. The thermal conductivity of the aerogel is 36 percent lower compared to several commercially available insulations when tested in 1 atmosphere of argon gas up to 800 C.

  20. STEEL TRUSS TENSION RING SUPPORTING DOME ROOF. TENSION RING COVERED ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    STEEL TRUSS TENSION RING SUPPORTING DOME ROOF. TENSION RING COVERED BY ARCHITECTURAL FINISH. TENSION RING ROLLER SUPPORT AT COLUMN OBSCURED BY COLUMN COVERINGS. - Houston Astrodome, 8400 Kirby Drive, Houston, Harris County, TX

  1. Technology Solutions Case Study: Insulating Concrete Forms

    SciTech Connect

    none,

    2012-10-01

    This Pacific Northwest National Laboratory project investigated insulating concrete forms—rigid foam, hollow walls that are filled with concrete for highly insulated, hurricane-resistant construction.

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

    SciTech Connect

    Shoup, R.W. |; Long, F.; Martin, T.H.

    1996-06-01

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

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

    NASA Astrophysics Data System (ADS)

    Khamzakhan, G.; Chaikovsky, S. A.

    2014-11-01

    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.

  4. Of Rings and Volcanoes

    NASA Astrophysics Data System (ADS)

    2002-01-01

    Office National d'Etudes et de Recherches Aérospatiales (ONERA) , Laboratoire d'Astrophysique de Grenoble (LAOG) and the DESPA and DASGAL laboratories of the Observatoire de Paris in France, in collaboration with ESO. The CONICA infra-red camera was built, under an ESO contract, by the Max-Planck-Institut für Astronomie (MPIA) (Heidelberg) and the Max-Planck Institut für Extraterrestrische Physik (MPE) (Garching) in Germany, in collaboration with ESO. Saturn - Lord of the rings ESO PR Photo 04a/02 ESO PR Photo 04a/02 [Preview - JPEG: 460 x 400 pix - 54k] [Normal - JPEG: 1034 x 800 pix - 200k] Caption : PR Photo 04a/02 shows the giant planet Saturn, as observed with the VLT NAOS-CONICA Adaptive Optics instrument on December 8, 2001; the distance was 1209 million km. It is a composite of exposures in two near-infrared wavebands (H and K) and displays well the intricate, banded structure of the planetary atmosphere and the rings. Note also the dark spot at the south pole at the bottom of the image. One of the moons, Tethys, is visible as a small point of light below the planet. It was used to guide the telescope and to perform the adaptive optics "refocussing" for this observation. More details in the text. Technical information about this photo is available below. This NAOS/CONICA image of Saturn ( PR Photo 04a/02 ), the second-largest planet in the solar system, was obtained at a time when Saturn was close to summer solstice in the southern hemisphere. At this moment, the tilt of the rings was about as large as it can be, allowing the best possible view of the planet's South Pole. That area was on Saturn's night side in 1982 and could therefore not be photographed during the Voyager encounter. The dark spot close to the South Pole is a remarkable structure that measures approximately 300 km across. It was only recently observed in visible light from the ground with a telescope at the Pic du Midi Observatory in the Pyrenees (France) - this is the first infrared image to

  5. The Enceladus Ring

    NASA Technical Reports Server (NTRS)

    2006-01-01

    [figure removed for brevity, see original site] The Enceladus Ring (labeled)

    This excellent view of the faint E ring -- a ring feature now known to be created by Enceladus -- also shows two of Saturn's small moons that orbit within the ring, among a field of stars in the background.

    The E ring extends from three to eight Saturn radii -- about 180,000 kilometers (118,000 miles) to 482,000 kilometers (300,000 miles). Its full extent is not visible in this view.

    Calypso (22 kilometers, or 14 miles across) and Helene (32 kilometers, or 20 miles across) orbit within the E ring's expanse. Helene skirts the outer parts of the E ring, but here it is projected in front of a region deeper within the ring.

    Calypso and Helene are trojan satellites, or moons that orbit 60 degrees in front or behind a larger moon. Calypso is a Tethys trojan and Helene is a trojan of Dione.

    An interesting feature of note in this image is the double-banded appearance of the E-ring, which is created because the ring is somewhat fainter in the ringplane than it is 500-1,000 kilometers (300-600 miles) above and below the ringplane. This appearance implies that the particles in this part of the ring have nonzero inclinations (a similar affect is seen in Jupiter's gossamer ring). An object with a nonzero inclination does not orbit exactly at Saturn's ringplane. Instead, its orbit takes it above and below the ringplane. Scientists are not entirely sure why the particles should have such inclinations, but they are fairly certain that the reason involves Enceladus.

    One possible explanation is that all the E ring particles come from the plume of icy material that is shooting due south out of the moon's pole. This means all of the particles are created with a certain velocity out of the ringplane, and then they orbit above and below that plane.

    Another possible explanation is that Enceladus produces particles with a range of speeds, but the moon gravitationally

  6. Metallization of electronic insulators

    DOEpatents

    Gottesfeld, Shimshon; Uribe, Francisco A.

    1994-01-01

    An electroplated element is formed to include an insulating substrate, a conducting polymer polymerized in situ on the substrate, and a metal layer deposited on the conducting polymer. In one application a circuit board is formed by polymerizing pyrrole on an epoxy-fiberglass substrate in a single step process and then electrodepositing a metal over the resulting polypyrrole polymer. No chemical deposition of the metal is required prior to electroplating and the resulting layer of substrate-polymer-metal has excellent adhesion characteristics. The metal deposition is surprisingly smooth and uniform over the relatively high resistance film of polypyrrole. A continuous manufacturing process is obtained by filtering the solution between successive substrates to remove polymer formed in the solution, by maintaining the solution oxidizing potential within selected limits, and by adding a strong oxidant, such as KMnO.sub.4 at periodic intervals to maintain a low sheet resistivity in the resulting conducting polymer film.

  7. Quantum Mechanics in Insulators

    SciTech Connect

    Aeppli, G.

    2009-08-20

    Atomic physics is undergoing a large revival because of the possibility of trapping and cooling ions and atoms both for individual quantum control as well as collective quantum states, such as Bose-Einstein condensates. The present lectures start from the 'atomic' physics of isolated atoms in semiconductors and insulators and proceed to coupling them together to yield magnets undergoing quantum phase transitions as well as displaying novel quantum states with no classical analogs. The lectures are based on: G.-Y. Xu et al., Science 317, 1049-1052 (2007); G. Aeppli, P. Warburton, C. Renner, BT Technology Journal, 24, 163-169 (2006); H. M. Ronnow et al., Science 308, 392-395 (2005) and N. Q. Vinh et al., PNAS 105, 10649-10653 (2008).

  8. Lightweight Ceramic Insulation

    NASA Technical Reports Server (NTRS)

    Wheeler, W. H.; Creedon, J. F.

    1986-01-01

    Fiber burnout process yields low densities. Low density attained by process of sacrificial burnout. Graphite or carbon fibers mixed into slurry of silica, alumina, and boron-compound fibers in amounts ranging from 25 to 75 percent of total fiber content by weight. Mixture formed into blocks and dried. Blocks placed in kiln and heated to 1,600 degrees F(870 degrees C) for several hours. Graphite or carbon fibers slowly oxidize away, leaving voids and reducing block density. Finally, blocks heated to 2,350 degrees F (1,290 degrees C) for 90 minutes to bond remaining ceramic fibers together. Developed for use on Space Shuttle and other spacecraft, rigid insulation machined to requisite shape and bonded in place.

  9. Boron nitride insulating material

    DOEpatents

    Morgan, Jr., Chester S.; Cavin, O. Burl; McCulloch, Reginald W.; Clark, David L.

    1978-01-01

    High temperature BN-insulated heaters for use as fuel pin simulators in reactor thermal hydraulic test facility studies comprise a cylindrical housing and a concentric heating element disposed within the housing and spaced apart from the housing to define an annular region therebetween. The annular region contains BN for providing electrical resistance and thermal conductivity between the housing and the heating element. The fabrication method of this invention comprises the steps of cold pressing BN powder at a pressure of 20 to 80,000 psig and a dwell time of at least 0.1-3 seconds to provide hollow cylindrical preforms of suitable dimensions for insertion into the annular region, the BN powder having a tap density of about 0.6-1.1 g/cm.sup.3 and an orientation ratio of at least about 100/3.5. The preforms are inserted into the annular region and crushed in place.

  10. Multiple layer insulation cover

    DOEpatents

    Farrell, James J.; Donohoe, Anthony J.

    1981-11-03

    A multiple layer insulation cover for preventing heat loss in, for example, a greenhouse, is disclosed. The cover is comprised of spaced layers of thin foil covered fabric separated from each other by air spaces. The spacing is accomplished by the inflation of spaced air bladders which are integrally formed in the cover and to which the layers of the cover are secured. The bladders are inflated after the cover has been deployed in its intended use to separate the layers of the foil material. The sizes of the material layers are selected to compensate for sagging across the width of the cover so that the desired spacing is uniformly maintained when the cover has been deployed. The bladders are deflated as the cover is stored thereby expediting the storage process and reducing the amount of storage space required.

  11. Keck Observations of Dusty Rings in our Solar System

    NASA Astrophysics Data System (ADS)

    de Pater, Imke

    2007-08-01

    All four giant planets are surrounded by ring systems, which typically consist of a combination of large and small bodies, as well as fine dust. With the 10-m W.M. Keck telescope on Mauna Kea (Hawaii) we have focused on observing the dusty rings of these planets. In this review I will summarize our data sets. I will focus on our most recent results with regard to Jupiter and Uranus, both observed during ring plane crossings. Jupiter's ring system was observed in December 2002 and January 2003 at 2.2 micron, where we used both the facility near-infrared camera NIRC with a pixel size of 0.151" (˜500 km at Jupiter), and the adaptive optics camera NIRC2, with a pixelsize of 0.04" and 0.01". The images were "onion-peeled" to provide radial scans of the rings. We will compare results of the main ring with Galileo data, and comment on similarities and differences with respect to the location of parent material in the ring. The radial structure of the gossamer rings is very different than expected based upon the Burns et al (1999) formation scenarios. The rings are not sheets of material, but narrow rings located just interior to the orbits of Amalthea and Thebe. The Amalthea ring shows a structure analagous to the main ring. Its inner boundary is near the location of synchronous orbit. Radial variations in the Thebe ring suggest "sculpting" by Lorentz resonances. We will present images of Uranus "hot of the press"; we are scheduled to observe in July and August when the rings are edge-on.

  12. Insulated face brick

    SciTech Connect

    Cromrich, J.; Cromrich, L.B.

    1990-10-16

    This patent describes a method for forming insulated brick intended solely for use in building walls and having superior insulation qualities and lighter weight consonant with the load bearing capabilities of building bricks and the appearance of facing brick. It comprises dry mixing two parts of vermiculite and one part of brick clay, thereby forming a dry mixture having a vermiculite to clay ratio of approximately two-to-one by volume; adding water to the dry mixture and mixing, so that a substantially dry admixture having expanded vermiculite and brick clay is formed; forming a facing layer solely from brick clay; molding and compressing the substantially dry admixture, so as to form a generally rectangular main body layer having parallel top and bottom faces, a pair of parallel side faces and a pair of parallel end faces, respectively, the top and bottom faces being substantially larger in area than the respective side faces, and the side faces being substantially larger in area than the respective end faces, the body layer further having at least one bore formed therein, the bore running from the top face to the bottom face perpendicularly thereto and substantially parallel to the side surfaces thereof, the bore being substantially centrally disposed and wherein the facing layer is disposed on one of the side surfaces of the body portion; curing the molded admixture having the facing layer disposed thereon; whereby a cured brick is formed; and firing the cured brick and the facing layer disposed thereon, whereby an integral brick is formed having top and bottom faces of the brick which are entirely devoid of facing layers, wherein the brick has the desired load bearing capability substantially between its top and bottom faces, whereby the outer facing layer only provides the desired appearance and weather resistance, and further whereby the weight of the brick is substantially reduced.

  13. Earth: A Ringed Planet?

    NASA Astrophysics Data System (ADS)

    Hancock, L. O.; Povenmire, H.

    2010-12-01

    Among the most beautiful findings of the Space Age have been the discoveries of planetary rings. Not only Saturn but also Jupiter, Uranus and Neptune have rings; Saturn’s ring system has structures newly discovered; even Saturn's moon Rhea itself has a ring. All these are apparently supplied by material from the planetary moons (Rhea's ring by Rhea itself). The question naturally arises, why should the Earth not have a ring, and on the other hand, if it does, why has it not been observed? No rings have yet been observed in the inner solar system, but after all, rings in the inner solar system might simply tend to be fainter and more transient than those of the outer solar system: the inner solar system is more affected by the solar wind, and the Sun’s perturbing gravitational influence is greater. J.A. O’Keefe first suggested (1980) that Earth might have a ring system of its own. An Earth ring could account for some climate events. O’Keefe remarked that formation or thickening of a ring system in Earth’s equatorial plane could drive glaciation by deepening the chill of the winter hemisphere. (It is very well established that volcanic dust is an effective agent for the extinction of sunlight; this factor can be overwhelmingly apparent in eclipse observations.) O’Keefe died in 2000 and the speculation was not pursued, but the idea of an Earth ring has a prima facie reasonableness that calls for its renewed consideration. The program of this note is to hypothesize that, as O’Keefe proposed: (a) an Earth ring system exists; (b) it affects Earth's weather and climate; (c) the tektite strewn fields comprise filaments of the ring fallen to Earth's surface on various occasions of disturbance by comets or asteroids. On this basis, and drawing on the world's weather records, together with the Twentieth Century Reanalysis by NCEP/CIRES covering the period 1870-2010 and the geology of the tektite strewn fields, we herein propose the hypothesized Earth ring

  14. Hot piston ring tests

    NASA Astrophysics Data System (ADS)

    Allen, David J.; Tomazic, William A.

    1987-12-01

    As part of the DOE/NASA Automotive Stirling Engine Project, tests were made at NASA Lewis Research Center to determine whether appendix gap losses could be reduced and Stirling engine performance increased by installing an additional piston ring near the top of each piston dome. An MTI-designed upgraded Mod I Automotive Stirling Engine was used. Unlike the conventional rings at the bottom of the piston, these hot rings operated in a high temperature environment (700 C). They were made of a high temperature alloy (Stellite 6B) and a high temperature solid lubricant coating (NASA Lewis-developed PS-200) was applied to the cylinder walls. Engine tests were run at 5, 10, and 15 MPa operating pressure over a range of operating speeds. Tests were run both with hot rings and without to provide a baseline for comparison. Minimum data to assess the potential of both the hot rings and high temperature low friction coating was obtained. Results indicated a slight increase in power and efficiency, an increase over and above the friction loss introduced by the hot rings. Seal leakage measurements showed a significant reduction. Wear on both rings and coating was low.

  15. Dynamics of narrow rings

    NASA Technical Reports Server (NTRS)

    Dermott, S. F.

    1984-01-01

    The ring models described here were developed to account for the dynamical problems posed by the narrow rings of Uranus. Some of these rings are now known to be eccentric, inclined, nonuniform in width, optically thick, and narrow, with very sharp edges. The eccentric rings have common pericenters and large, positive eccentricity gradients. The theory of shepherding satellites successfully accounts for most of these features and can also account for some features of the narrow Saturnian rings, in particular, waves, kinks, and periodic variations in brightness. Outstanding problems include the putative relation between eccentricity and inclination displayed by eight of the nine Uranian rings, and the magnitudes of the tidal torques acting on the shepherding satellites. The horseshoe-orbit model, although viable, probably has more application to the narrow rings from which the Saturnian coorbital satellites formed. The angular momentum flow rate due to particle collisions is a minimum at the Lagrangian equilibrium points L(4) and L(5), and one can expect accretion to be rapid at these points.

  16. Hot piston ring tests

    NASA Technical Reports Server (NTRS)

    Allen, David J.; Tomazic, William A.

    1987-01-01

    As part of the DOE/NASA Automotive Stirling Engine Project, tests were made at NASA Lewis Research Center to determine whether appendix gap losses could be reduced and Stirling engine performance increased by installing an additional piston ring near the top of each piston dome. An MTI-designed upgraded Mod I Automotive Stirling Engine was used. Unlike the conventional rings at the bottom of the piston, these hot rings operated in a high temperature environment (700 C). They were made of a high temperature alloy (Stellite 6B) and a high temperature solid lubricant coating (NASA Lewis-developed PS-200) was applied to the cylinder walls. Engine tests were run at 5, 10, and 15 MPa operating pressure over a range of operating speeds. Tests were run both with hot rings and without to provide a baseline for comparison. Minimum data to assess the potential of both the hot rings and high temperature low friction coating was obtained. Results indicated a slight increase in power and efficiency, an increase over and above the friction loss introduced by the hot rings. Seal leakage measurements showed a significant reduction. Wear on both rings and coating was low.

  17. Seasonal acclimatization determined by non-invasive measurements of coat insulation.

    PubMed

    Langman, Vaughan A; Langman, Sarah L; Ellifrit, Nancy

    2015-01-01

    Seasonal acclimatization in terrestrial mammals in the Northern Hemisphere involves changes in coat insulation. It is more economical to provide increased insulation than increased heat production for protection against the cold. This study was done to test a technique for the non-invasive measurement of mammal coat insulation and to measure coat insulation over several seasons on captive exotics. The working hypothesis was that species that have no coat or have a coat that does not change seasonally do not acclimatize seasonally. Three surface temperature readings were measured from the torso area. The insulation was calculated using measured metabolic rates and body temperature when possible. The African elephants, giraffe and okapi did not acclimatize with average maximum insulation values of 0.256°Cm(2)  W(-1) . The Amur tigers and mountain goats acclimatized to seasonal ambient conditions by increasing the insulation values of the hair coats in the cold with an average maximum insulation values of 0.811°Cm(2)  W(-1) . The cold adapted species are more than three times more insulated in the cold than the equatorial species. The husbandry implications of exotics that have no ability to acclimatize to Northern Hemisphere seasonal ambient changes are profound. Giraffe, African elephants, and okapi when exposed to cold conditions with ambient air temperatures below 21°C will use body energy reserves to maintain a heat balance and will require housing that provides ambient conditions of 21°C.

  18. Seasonal acclimatization determined by non-invasive measurements of coat insulation.

    PubMed

    Langman, Vaughan A; Langman, Sarah L; Ellifrit, Nancy

    2015-01-01

    Seasonal acclimatization in terrestrial mammals in the Northern Hemisphere involves changes in coat insulation. It is more economical to provide increased insulation than increased heat production for protection against the cold. This study was done to test a technique for the non-invasive measurement of mammal coat insulation and to measure coat insulation over several seasons on captive exotics. The working hypothesis was that species that have no coat or have a coat that does not change seasonally do not acclimatize seasonally. Three surface temperature readings were measured from the torso area. The insulation was calculated using measured metabolic rates and body temperature when possible. The African elephants, giraffe and okapi did not acclimatize with average maximum insulation values of 0.256°Cm(2)  W(-1) . The Amur tigers and mountain goats acclimatized to seasonal ambient conditions by increasing the insulation values of the hair coats in the cold with an average maximum insulation values of 0.811°Cm(2)  W(-1) . The cold adapted species are more than three times more insulated in the cold than the equatorial species. The husbandry implications of exotics that have no ability to acclimatize to Northern Hemisphere seasonal ambient changes are profound. Giraffe, African elephants, and okapi when exposed to cold conditions with ambient air temperatures below 21°C will use body energy reserves to maintain a heat balance and will require housing that provides ambient conditions of 21°C. PMID:26087320

  19. Dynamics of the Uranian Rings

    NASA Technical Reports Server (NTRS)

    Dermott, S. F.

    1984-01-01

    Some of the problems of the shepherding satellite model of Goldreich ant tremaine are discussed. The following topics are studied: (1) optical depths of the all the observed narrow rings; (2) satellite and ring separation timescales; (3) ring edge sharpness; (4) shock formation in narrow rings; (5) the existence of small satellites near the Uranian rings; and (6) the apse and node alignments of the eccentric and inclined rings.

  20. Theodolite Ring Lights

    NASA Technical Reports Server (NTRS)

    Clark, David

    2006-01-01

    Theodolite ring lights have been invented to ease a difficulty encountered in the well-established optical-metrology practice of using highly reflective spherical tooling balls as position references. A theodolite ring light produces a more easily visible reflection and eliminates the need for an autocollimating device. A theodolite ring light is a very bright light source that is well centered on the optical axis of the instrument. It can be fabricated, easily and inexpensively, for use on a theodolite or telescope of any diameter.

  1. Alternative parallel ring protocols

    NASA Technical Reports Server (NTRS)

    Mukkamala, R.; Foudriat, E. C.; Maly, Kurt J.; Kale, V.

    1990-01-01

    Communication protocols are know to influence the utilization and performance of communication network. The effect of two token ring protocols on a gigabit network with multiple ring structure is investigated. In the first protocol, a mode sends at most one message on receiving a token. In the second protocol, a mode sends all the waiting messages when a token is received. The behavior of these protocols is shown to be highly dependent on the number of rings as well as the load in the network.

  2. Lightweight, Thermally Insulating Structural Panels

    NASA Technical Reports Server (NTRS)

    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.

  3. Storage Ring EDM Experiments

    NASA Astrophysics Data System (ADS)

    Semertzidis, Yannis K.

    2016-04-01

    Dedicated storage ring electric dipole moment (EDM) methods show great promise advancing the sensitivity level by a couple orders of magnitude over currently planned hadronic EDM experiments. We describe the present status and recent updates of the field.

  4. Highlights in planetary rings

    NASA Astrophysics Data System (ADS)

    Porco, Carolyn C.

    1995-07-01

    There is a rich phenomenology within the planetary rings surrounding the giant planets, most of it discovered by the Voyagers during their historic tours of t he outer solar system in the 1980s. In the last decade, there have been two detailed IUGG reviews of planetary rings. Cuzzi [1983] covered the time period from 1979-1983 which included the Pioneer 11 encounter with Saturn (1979), the Voyager 1 and 2 encounters with Jupiter (1979) and with Saturn (1980 and 1981). Nicholson and Dones [1991] reviewed the developments in the field between 1984 and 1991, a period of time which included the Voyager 2 Uranus (1986) and Neptune (1989) encounters. (References t o additional reviews of planetary rings and related fields can be found in Nicholson and Dones [1991].) Rather than being comprehensive in nature, this review will concentrate on only those areas of ring research in which particularly promising developments have occurred in the last half decade.

  5. Heating Saturn's Clumpy Rings

    NASA Astrophysics Data System (ADS)

    Turner, Neal J.; Morishima, Ryuji; Spilker, Linda J.

    2015-11-01

    We model Cassini CIRS data using a Monte Carlo radiative transfer -- thermal balance technique first developed for protostellar disks, with the goals of:1. Exploring whether the A- and B-ring temperatures' variation with viewing angle is consistent with the wake structures suggested by the observed azimuthal asymmetry in optical depth, by analytic arguments, and by numerical N-body modeling.2. Better constraining the shape, size, spacing and optical depths of substructure in the A-ring, using the unexpectedly high temperatures observed at equinox. If the wake features have high enough contrast, Saturn-shine may penetrate the gaps between the wakes and heat thering particles both top and bottom.3. Determining how much of the heating of the A- and B-rings' unlit sides is due to radiative transport and how much is due to particle motions, especially vertical motions. This will help in constraining the rings' surface densities and masses.

  6. Saturn's dynamic D ring

    USGS Publications Warehouse

    Hedman, M.M.; Burns, J.A.; Showalter, M.R.; Porco, C.C.; Nicholson, P.D.; Bosh, A.S.; Tiscareno, M.S.; Brown, R.H.; Buratti, B.J.; Baines, K.H.; Clark, R.

    2007-01-01

    The Cassini spacecraft has provided the first clear images of the D ring since the Voyager missions. These observations show that the structure of the D ring has undergone significant changes over the last 25 years. The brightest of the three ringlets seen in the Voyager images (named D72), has transformed from a narrow, <40-km wide ringlet to a much broader and more diffuse 250-km wide feature. In addition, its center of light has shifted inwards by over 200 km relative to other features in the D ring. Cassini also finds that the locations of other narrow features in the D ring and the structure of the diffuse material in the D ring differ from those measured by Voyager. Furthermore, Cassini has detected additional ringlets and structures in the D ring that were not observed by Voyager. These include a sheet of material just interior to the inner edge of the C ring that is only observable at phase angles below about 60??. New photometric and spectroscopic data from the ISS (Imaging Science Subsystem) and VIMS (Visual and Infrared Mapping Spectrometer) instruments onboard Cassini show the D ring contains a variety of different particle populations with typical particle sizes ranging from 1 to 100 microns. High-resolution images reveal fine-scale structures in the D ring that appear to be variable in time and/or longitude. Particularly interesting is a remarkably regular, periodic structure with a wavelength of ??? 30 ?? km extending between orbital radii of 73,200 and 74,000 km. A similar structure was previously observed in 1995 during the occultation of the star GSC5249-01240, at which time it had a wavelength of ??? 60 ?? km. We interpret this structure as a periodic vertical corrugation in the D ring produced by differential nodal regression of an initially inclined ring. We speculate that this structure may have formed in response to an impact with a comet or meteoroid in early 1984. ?? 2006 Elsevier Inc. All rights reserved.

  7. Ultrasonic Newton's rings

    SciTech Connect

    Hsu, D.K. ); Dayal, V. )

    1992-03-09

    Interference fringes due to bondline thickness variation were observed in ultrasonic scans of the reflected echo amplitude from the bondline of adhesively joined aluminum skins. To demonstrate that full-field interference patterns are observable in point-by-point ultrasonic scans, an optical setup for Newton's rings was scanned ultrasonically in a water immersion tank. The ultrasonic scan showed distinct Newton's rings whose radii were in excellent agreement with the prediction.

  8. Nardo Ring, Italy

    NASA Technical Reports Server (NTRS)

    2008-01-01

    The Nardo Ring is a striking visual feature from space, and astronauts have photographed it several times. The Ring is a race car test track; it is 12.5 kilometers long and steeply banked to reduce the amount of active steering needed by drivers. The Nardo Ring lies in a remote area on the heel of Italy's 'boot,' 50 kilometers east of the naval port of Taranto. The Ring encompasses a number of active (green) and fallow (brown to dark brown) agricultural fields. In this zone of intensive agriculture, farmers gain access to their fields through the Ring via a series of underpasses. Winding features within the southern section of the Ring appear to be smaller, unused race tracks.

    The image covers an area of 18.8 x 16.4 km, was acquired on August 17. 2007, and is located at 49.3 degrees north latitude, 17.8 degrees east longitude.

    The U.S. science team is located at NASA's Jet Propulsion Laboratory, Pasadena, Calif. The Terra mission is part of NASA's Science Mission Directorate.

  9. 46 CFR 153.240 - Insulation.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 46 Shipping 5 2013-10-01 2013-10-01 false Insulation. 153.240 Section 153.240 Shipping COAST GUARD....240 Insulation. Cargo containment system insulation made necessary by the requirements of this part....05-20(b) is unnecessary if the insulation is: (a) Protected from the weather, and attached to...

  10. 49 CFR 179.200-4 - Insulation.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 49 Transportation 3 2014-10-01 2014-10-01 false Insulation. 179.200-4 Section 179.200-4...-Pressure Tank Car Tanks (Classes DOT-111AW and 115AW) § 179.200-4 Insulation. (a) If insulation is applied... insulation must be covered with a metal jacket of a thickness not less than 11 gauge (0.1196 inch)...

  11. 49 CFR 179.100-4 - Insulation.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 49 Transportation 3 2014-10-01 2014-10-01 false Insulation. 179.100-4 Section 179.100-4... Tank Car Tanks (Classes DOT-105, 109, 112, 114 and 120) § 179.100-4 Insulation. (a) If insulation is... insulation must be covered with a metal jacket of a thickness not less than 11 gauge (0.1196 inch)...

  12. 46 CFR 153.240 - Insulation.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 46 Shipping 5 2011-10-01 2011-10-01 false Insulation. 153.240 Section 153.240 Shipping COAST GUARD....240 Insulation. Cargo containment system insulation made necessary by the requirements of this part....05-20(b) is unnecessary if the insulation is: (a) Protected from the weather, and attached to...

  13. 49 CFR 179.200-4 - Insulation.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 49 Transportation 3 2012-10-01 2012-10-01 false Insulation. 179.200-4 Section 179.200-4...-Pressure Tank Car Tanks (Classes DOT-111AW and 115AW) § 179.200-4 Insulation. (a) If insulation is applied... insulation must be covered with a metal jacket of a thickness not less than 11 gauge (0.1196 inch)...

  14. 49 CFR 179.100-4 - Insulation.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 49 Transportation 3 2012-10-01 2012-10-01 false Insulation. 179.100-4 Section 179.100-4... Tank Car Tanks (Classes DOT-105, 109, 112, 114 and 120) § 179.100-4 Insulation. (a) If insulation is... insulation must be covered with a metal jacket of a thickness not less than 11 gauge (0.1196 inch)...

  15. 46 CFR 153.240 - Insulation.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 46 Shipping 5 2014-10-01 2014-10-01 false Insulation. 153.240 Section 153.240 Shipping COAST GUARD....240 Insulation. Cargo containment system insulation made necessary by the requirements of this part....05-20(b) is unnecessary if the insulation is: (a) Protected from the weather, and attached to...

  16. 49 CFR 179.200-4 - Insulation.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 49 Transportation 3 2013-10-01 2013-10-01 false Insulation. 179.200-4 Section 179.200-4...-Pressure Tank Car Tanks (Classes DOT-111AW and 115AW) § 179.200-4 Insulation. (a) If insulation is applied... insulation must be covered with a metal jacket of a thickness not less than 11 gauge (0.1196 inch)...

  17. 49 CFR 179.100-4 - Insulation.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 49 Transportation 3 2013-10-01 2013-10-01 false Insulation. 179.100-4 Section 179.100-4... Tank Car Tanks (Classes DOT-105, 109, 112, 114 and 120) § 179.100-4 Insulation. (a) If insulation is... insulation must be covered with a metal jacket of a thickness not less than 11 gauge (0.1196 inch)...

  18. 16 CFR 460.18 - Insulation ads.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 16 Commercial Practices 1 2010-01-01 2010-01-01 false Insulation ads. 460.18 Section 460.18 Commercial Practices FEDERAL TRADE COMMISSION TRADE REGULATION RULES LABELING AND ADVERTISING OF HOME INSULATION § 460.18 Insulation ads. (a) If your ad gives an R-value, you must give the type of insulation...

  19. 16 CFR 460.18 - Insulation ads.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 16 Commercial Practices 1 2012-01-01 2012-01-01 false Insulation ads. 460.18 Section 460.18 Commercial Practices FEDERAL TRADE COMMISSION TRADE REGULATION RULES LABELING AND ADVERTISING OF HOME INSULATION § 460.18 Insulation ads. (a) If your ad gives an R-value, you must give the type of insulation...

  20. 16 CFR 460.18 - Insulation ads.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 16 Commercial Practices 1 2013-01-01 2013-01-01 false Insulation ads. 460.18 Section 460.18 Commercial Practices FEDERAL TRADE COMMISSION TRADE REGULATION RULES LABELING AND ADVERTISING OF HOME INSULATION § 460.18 Insulation ads. (a) If your ad gives an R-value, you must give the type of insulation...

  1. 16 CFR 460.18 - Insulation ads.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 16 Commercial Practices 1 2014-01-01 2014-01-01 false Insulation ads. 460.18 Section 460.18 Commercial Practices FEDERAL TRADE COMMISSION TRADE REGULATION RULES LABELING AND ADVERTISING OF HOME INSULATION § 460.18 Insulation ads. (a) If your ad gives an R-value, you must give the type of insulation...

  2. 16 CFR 460.18 - Insulation ads.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 16 Commercial Practices 1 2011-01-01 2011-01-01 false Insulation ads. 460.18 Section 460.18 Commercial Practices FEDERAL TRADE COMMISSION TRADE REGULATION RULES LABELING AND ADVERTISING OF HOME INSULATION § 460.18 Insulation ads. (a) If your ad gives an R-value, you must give the type of insulation...

  3. 49 CFR 179.100-4 - Insulation.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 49 Transportation 2 2010-10-01 2010-10-01 false Insulation. 179.100-4 Section 179.100-4... Specifications for Pressure Tank Car Tanks (Classes DOT-105, 109, 112, 114 and 120) § 179.100-4 Insulation. (a) If insulation is applied, the tank shell and manway nozzle must be insulated with an...

  4. 49 CFR 179.200-4 - Insulation.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 49 Transportation 2 2010-10-01 2010-10-01 false Insulation. 179.200-4 Section 179.200-4... Specifications for Non-Pressure Tank Car Tanks (Classes DOT-111AW and 115AW) § 179.200-4 Insulation. (a) If insulation is applied, the tank shell and expansion dome when used must be insulated with an...

  5. 49 CFR 179.100-4 - Insulation.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 49 Transportation 3 2011-10-01 2011-10-01 false Insulation. 179.100-4 Section 179.100-4... Tank Car Tanks (Classes DOT-105, 109, 112, 114 and 120) § 179.100-4 Insulation. (a) If insulation is... insulation must be covered with a metal jacket of a thickness not less than 11 gauge (0.1196 inch)...

  6. 49 CFR 179.200-4 - Insulation.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 49 Transportation 3 2011-10-01 2011-10-01 false Insulation. 179.200-4 Section 179.200-4...-Pressure Tank Car Tanks (Classes DOT-111AW and 115AW) § 179.200-4 Insulation. (a) If insulation is applied... insulation must be covered with a metal jacket of a thickness not less than 11 gauge (0.1196 inch)...

  7. Cohesin regulates MHC class II genes through interactions with MHC class II insulators.

    PubMed

    Majumder, Parimal; Boss, Jeremy M

    2011-10-15

    Cohesin is a multiprotein, ringed complex that is most well-known for its role in stabilizing the association of sister chromatids between S phase and M. More recently, cohesin was found to be associated with transcriptional insulators, elements that are associated with the organization of chromatin into regulatory domains. The human MHC class II (MHC-II) locus contains 10 intergenic elements, termed MHC-II insulators, which bind the transcriptional insulator protein CCCTC-binding factor. MHC-II insulators interact with each other, forming a base architecture of discrete loops and potential regulatory domains. When MHC-II genes are expressed, their proximal promoter regulatory regions reorganize to the foci established by the interacting MHC-II insulators. MHC-II insulators also bind cohesin, but the functional role of cohesin in regulating this system is not known. In this article, we show that the binding of cohesin to MHC-II insulators occurred irrespective of MHC-II expression but was required for optimal expression of the HLA-DR and HLA-DQ genes. In a DNA-dependent manner, cohesin subunits interacted with CCCTC-binding factor and the MHC-II-specific transcription factors regulatory factor X and CIITA. Intriguingly, cohesin subunits were important for DNA looping interactions between the HLA-DRA promoter region and a 5' MHC-II insulator but were not required for interactions between the MHC-II insulators themselves. This latter observation introduces cohesin as a regulator of MHC-II expression by initiating or stabilizing MHC-II promoter regulatory element interactions with the MHC-II insulator elements, events that are required for maximal MHC-II transcription.

  8. The alternatives for insulation testing.

    PubMed

    Backes, John

    2010-04-01

    Electrical safety testing of medical equipment is essential to ensure that the apparatus is safe for operators and patients alike. Rigel Medical's John Backes looks at the latest tests used to assess the integrity of insulation in electrical appliances.

  9. Measure Guideline: Basement Insulation Basics

    SciTech Connect

    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.

  10. Light-weight ceramic insulation

    NASA Technical Reports Server (NTRS)

    Hsu, Ming-Ta S. (Inventor); Chen, Timothy S. (Inventor)

    2002-01-01

    Ultra-high temperature, light-weight, ceramic insulation such as ceramic tile is obtained by pyrolyzing a siloxane gel derived from the reaction of at least one organo dialkoxy silane and at least one tetralkoxy silane in an acid or base liquid medium. The reaction mixture of the tetra- and dialkoxy silanes may contain also an effective amount of a mono- or trialkoxy silane to obtain the siloxane gel. The siloxane gel is dried at ambient pressures to form a siloxane ceramic precursor without significant shrinkage. The siloxane ceramic precursor is subsequently pyrolyzed, in an inert atmosphere, to form the black ceramic insulation comprising atoms of silicon, carbon and oxygen. The ceramic insulation, can be characterized as a porous, uniform ceramic tile resistant to oxidation at temperatures ranging as high as 1700.degree. C. and is particularly useful as lightweight tiles for spacecraft and other high-temperature insulation applications.

  11. Metal-Insulator-Semiconductor Photodetectors

    PubMed Central

    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. PMID:22163382

  12. Field insulation materials and problems

    NASA Astrophysics Data System (ADS)

    Vogt, G. H.

    1981-12-01

    In a turbine generator the rotating field requires insulation materials and design considerations much different from the high voltage insulation used for armature windings. The principal properties to be looked for are mechanical strength, resistance to abrasion and resistance to thermal degradation. Electrical strength is also important because field windings are required to withstand a high potential test of ten times rated voltage. Some of the materials used over the years ranged from various kinds of fibers and flake mica composites, to asbestos, fiberglass epoxy or polyester laminates, Nomex and combinations of fiberglass, Nomex and insulating films. New materials have been applied to satisfy demands for better properties as generators grew in size and output, and it is the new materials that have made it possible to obtain more power from smaller machines. Field insulation materials and problems are discussed further.

  13. Heat insulation structure for rooftops of buildings

    SciTech Connect

    Ueno, K.; suizu, Y.

    1985-10-15

    A heat insulation structure for rooftops, coated with a waterproof layer, including: a plurality of heat insulation panels; a plurality of protective panels; and devices, supported on the waterproof layer, for supporting the insulation panels so that an air gap is formed between the waterproof layer and the insulation panels to form an air layer and for supporting the protective panels so that the protective panels are positioned above the insulation panels, the insulation panels being arranged in a side by side relation to thereby form an insulation layer, and the protective panels being arranged in a side by side relation to thereby form a protective layer.

  14. Propellers in Saturn's rings

    NASA Astrophysics Data System (ADS)

    Sremcevic, M.; Stewart, G. R.; Albers, N.; Esposito, L. W.

    2014-04-01

    Theoretical studies and simulations have demonstrated the effects caused by objects embedded in planetary rings [5, 8]. Even if the objects are too small to be directly observed, each creates a much larger gravitational imprint on the surrounding ring material. These strongly depend on the mass of the object and range from "S" like propeller-shaped structures for about 100m-sized icy bodies to the opening of circumferential gaps as in the case of the embedded moons Pan and Daphnis and their corresponding Encke and Keeler Gaps. Since the beginning of the Cassini mission many of these smaller objects (~ 100m in size) have been identified in Saturn's A ring through their propeller signature in the images [10, 7, 9, 11]. Furthermore, recent Cassini observations indicate the possible existence of objects embedded even in Saturn's B and C ring [6, 2]. In this paper we present our new results about by now classical A ring propellers and more enigmatic B ring population. Due to the presence of self-gravity wakes the analysis of propeller brightness in ISS images always bears some ambiguity [7, 9] and consequently the exact morphology of propellers is not a settled issue. In 2008 we obtained a fortunate Cassini Ultraviolet Imaging Spectrograph (UVIS) occultation of the largest A ring propeller Bleriot. Utilizing Cassini ISS images we obtain Bleriot orbit and demonstrate that UVIS Persei Rev42 occultation did cut across Bleriot about 100km downstream from the center. The occultation itself shows a prominent partial gap and higher density outer flanking wakes, while their orientation is consistent with a downstream cut. While in the UVIS occultation the partial gap is more prominent than the flanking wakes, the features mostly seen in Bleriot images are actually flanking wakes. One of the most interesting aspects of the A ring propellers are their wanderings, or longitudinal deviations from a pure circular orbit [11]. We numerically investigated the possibility of simple moon

  15. Design and implementation of a fiber optic link for a token ring local area network

    NASA Astrophysics Data System (ADS)

    Doran, Thomas J.

    1992-09-01

    This thesis describes the design and implementation of a fiber optic link for a token ring local area network (LAN). It features the use of fiber optic channels as the transmission medium between a computer system and a wiring concentrator to convert a physical ring design into a starwired configuration. The LAN was controlled by the TMS380 LAN Adapter chipset, which provided all diagnostic and network management features to include the 4 Mb/s electrical signal for operation. Since this adapter was developed for systems using twisted wire pair adapter cables, design modifications required that the fiber link be able to simulate impedance and current characteristics of copper wire link. This allows the use of adapter diagnostic checks for ring continuity and proper ring operation. Design evaluations using test signals and adapter signals from within the computer-concentrator link showed mixed results. All transmission objectives were met but the circuit loaded down the LAN adapter causing hardware error messages.

  16. Molecular dewetting on insulators.

    PubMed

    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.

  17. High Voltage Insulation Technology

    NASA Astrophysics Data System (ADS)

    Scherb, V.; Rogalla, K.; Gollor, M.

    2008-09-01

    In preparation of new Electronic Power Conditioners (EPC's) for Travelling Wave Tub Amplifiers (TWTA's) on telecom satellites a study for the development of new high voltage insulation technology is performed. The initiative is mandatory to allow compact designs and to enable higher operating voltages. In a first task a market analysis was performed, comparing different materials with respect to their properties and processes. A hierarchy of selection criteria was established and finally five material candidates (4 Epoxy resins and 1 Polyurethane resin) were selected to be further investigated in the test program. Samples for the test program were designed to represent core elements of an EPC, the high voltage transformer and Printed Circuit Boards of the high voltage section. All five materials were assessed in the practical work flow of the potting process and electrical, mechanical, thermal and lifetime testing was performed. Although the lifetime tests results were overlayed by a larges scatter, finally two candidates have been identified for use in a subsequent qualification program. This activity forms part of element 5 of the ESA ARTES Programme.

  18. Model Fractional Chern Insulators

    NASA Astrophysics Data System (ADS)

    Behrmann, Jörg; Liu, Zhao; Bergholtz, Emil J.

    2016-05-01

    We devise local lattice models whose ground states are model fractional Chern insulators—Abelian and non-Abelian topologically ordered states characterized by exact ground state degeneracies at any finite size and infinite entanglement gaps. Most saliently, we construct exact parent Hamiltonians for two distinct families of bosonic lattice generalizations of the Zk parafermion quantum Hall states: (i) color-entangled fractional Chern insulators at band filling fractions ν =k /(C +1 ) and (ii) nematic states at ν =k /2 , where C is the Chern number of the lowest band. In spite of a fluctuating Berry curvature, our construction is partially frustration free: the ground states reside entirely within the lowest band and exactly minimize a local (k +1 ) body repulsion term by term. In addition to providing the first known models hosting intriguing states such as higher Chern number generalizations of the Fibonacci anyon quantum Hall states, the remarkable stability and finite-size properties make our models particularly well suited for the study of novel phenomena involving, e.g., twist defects and proximity induced superconductivity, as well as being a guide for designing experiments.

  19. Advanced silicon on insulator technology

    NASA Technical Reports Server (NTRS)

    Godbey, D.; Hughes, H.; Kub, F.

    1991-01-01

    Undoped, thin-layer silicon-on-insulator was fabricated using wafer bonding and selective etching techniques employing a molecular beam epitaxy (MBE) grown Si0.7Ge0.3 layer as an etch stop. Defect free, undoped 200-350 nm silicon layers over silicon dioxide are routinely fabricated using this procedure. A new selective silicon-germanium etch was developed that significantly improves the ease of fabrication of the bond and etch back silicon insulator (BESOI) material.

  20. Variable pressure thermal insulating jacket

    DOEpatents

    Nelson, P.A.; Malecha, R.F.; Chilenskas, A.A.

    1994-09-20

    A device for controlled insulation of a thermal device is disclosed. The device includes a thermal jacket with a closed volume able to be evacuated to form an insulating jacket around the thermal source. A getter material is in communication with the closed volume of the thermal jacket. The getter material can absorb and desorb a control gas to control gas pressure in the volume of the thermal jacket to control thermal conductivity in the thermal jacket. 10 figs.

  1. Variable pressure thermal insulating jacket

    DOEpatents

    Nelson, Paul A.; Malecha, Richard F.; Chilenskas, Albert A.

    1994-01-01

    A device for controlled insulation of a thermal device. The device includes a thermal jacket with a closed volume able to be evacuated to form an insulating jacket around the thermal source. A getter material is in communcation with the closed volume of the thermal jacket. The getter material can absorb and desorb a control gas to control gas pressure in the volume of the thermal jacket to control thermal conductivity in the thermal jacket.

  2. Fully synthetic taped insulation cables

    DOEpatents

    Forsyth, Eric B.; Muller, Albert C.

    1984-01-01

    A high voltage oil-impregnated electrical cable with fully polymer taped insulation operable to 765 kV. Biaxially oriented, specially processed, polyethylene, polybutene or polypropylene tape with an embossed pattern is wound in multiple layers over a conductive core with a permeable screen around the insulation. Conventional oil which closely matches the dielectric constant of the tape is used, and the cable can be impregnated after field installation because of its excellent impregnation characteristics.

  3. Lung function in insulation workers.

    PubMed Central

    Clausen, J; Netterstrøm, B; Wolff, C

    1993-01-01

    To evaluate the effects of working with modern insulation materials (rock and glass wool), the members of the Copenhagen Union of Insulation Workers were invited to participate in a study based on a health examination that included lung function tests. Three hundred and forty men (74%) agreed to participate, and 166 bus drivers served as the control group. Age distribution, height, and smoking habits were similar in the two groups. Forced vital capacity (FVC) and forced expiratory volume in one second (FEV1) were used as tests for lung function. There were no differences in FVC between the study and control groups, but the insulation workers had significantly lower values of FEV1 (mean 2.51) compared with the controls (mean 3.4 1), independent of smoking habits. Six years before the present study, 114 of the insulation workers participated in a similar study, and eight years after the initial study, the lung function of 59 of the bus drivers was tested. The decline in FVC in insulation workers who smoked was significantly higher (7.7 cl/year) than in bus drivers who smoked (3.1 cl/year); the decline in FEV1 was significantly higher in insulation workers independent of smoking habits (17.0 cl/year v 2.9 cl/year). Self assessed former exposure to asbestos was not associated with lung function in insulation workers. The study concludes that working with modern insulation materials is associated with increased risk of developing obstructive lung disease. PMID:8457492

  4. Cryogenic foam insulation: Abstracted publications

    NASA Technical Reports Server (NTRS)

    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.

  5. Advances in cryogenic foam insulations.

    NASA Technical Reports Server (NTRS)

    Lemons, C. R.; Salmassy, O. K.; Watts, C. R.

    1971-01-01

    Description of a discretely oriented thread-reinforced polyurethane foam thermal insulation system for liquid hydrogen fuel tanks. The 3-D foam and glass liner composite is designed to be adhesively bonded to the inside surface of the tank wall and to be in direct contact with liquid hydrogen. All elements of this insulation composite are capable of sustaining the loads and environmental conditions imposed by testing under simulated Space Shuttle vehicle requirements at temperatures between -423 and +350 F.

  6. Method and means of directing an ion beam onto an insulating surface for ion implantation or sputtering

    DOEpatents

    Gruen, Dieter M.; Krauss, Alan R.; Siskind, Barry

    1981-01-01

    A beam of ions is directed under control onto an insulating surface by supplying simultaneously a stream of electrons directed at the same surface in a quantity sufficient to neutralize the overall electric charge of the ion beam and result in a net zero current flow to the insulating surface. The ion beam is adapted particularly both to the implantation of ions in a uniform areal disposition over the insulating surface and to the sputtering of atoms or molecules of the insulator onto a substrate.

  7. Electrical control of spin in topological insulators

    NASA Astrophysics Data System (ADS)

    Chang, Kai

    2012-02-01

    by changing the gate voltage. It provides us a new way to control surface magnetism electrically. The gap opened by doped magnetic ions can lead to a short-range Bloembergen-Rowland interaction. The competition among the Heisenberg, Ising, and DM terms leads to rich spin configurations and an anomalous Hall effect on different lattices [4]. There are many proposals for quantum computation scheme are based on the spin in semiconductor quantum dots. Topological insulator quantum dots display a very different behavior with that of conventional semiconductor quantum dots [5]. In sharp contrast to conventional semiconductor quantum dots, the quantum states in the gap of the HgTe QD are fully spin-polarized and show ring-like density distributions near the boundary of the QD and optically dark. The persistent charge currents and magnetic moments, i.e., the Aharonov-Bohm effect, can be observed in such a QD structure. This feature offers us a practical way to detect these exotic ring-like edge states by using the SQUID technique. [0pt]Refs: [1] W. Yang, Kai Chang, and S. C. Zhang, Phys. Rev. Lett. 100, 056602 (2008); J. Li and Kai Chang, Appl. Phys. Lett. 95, 222110 (2009). [2] L. B. Zhang, Kai Chang, X. C. Xie, H. Buhmann and L. W. Molenkamp, New J. Phys. 12, 083058 (2010). [3] L. B. Zhang, F. Cheng, F. Zhai and Kai Chang, Phys. Rev. B 83 081402(R) (2011); Z. H. Wu, F. Zhai, F. M. Peeters, H. Q. Xu and Kai Chang, Phys, Rev. Lett. 106, 176802 (2011). [4] J. J. Zhu, D. X. Yao, S. C. Zhang, and Kai Chang, Phys. Rev. Lett. 106, 097201 (2011). [5] Kai Chang, and Wen-Kai Lou, Phys. Rev. Lett. 106, 206802 (2011).

  8. Advances in Microsphere Insulation Systems

    NASA Astrophysics Data System (ADS)

    Allen, M. S.; Baumgartner, R. G.; Fesmire, J. E.; Augustynowicz, S. D.

    2004-06-01

    Microsphere insulation, typically consisting of hollow glass bubbles, combines in a single material the desirable properties that other insulations only have individually. The material has high crush strength, low density, is noncombustible, and performs well in soft vacuum. Microspheres provide robust, low-maintenance insulation systems for cryogenic transfer lines and dewars. They also do not suffer from compaction problems typical of perlite that result in the necessity to reinsulate dewars because of degraded thermal performance and potential damage to its support system. Since microspheres are load bearing, autonomous insulation panels enveloped with lightweight vacuum-barrier materials can be created. Comprehensive testing performed at the Cryogenics Test Laboratory located at the NASA Kennedy Space Center demonstrated competitive thermal performance with other bulk materials. Test conditions were representative of actual-use conditions and included cold vacuum pressure ranging from high vacuum to no vacuum and compression loads from 0 to 20 psi. While microspheres have been recognized as a legitimate insulation material for decades, actual implementation has not been pursued. Innovative microsphere insulation system configurations and applications are evaluated.

  9. Retaining-Ring Installation Tool

    NASA Technical Reports Server (NTRS)

    Christian, S.

    1983-01-01

    New tool eliminates damage to ring through improper tool use. Tool installs spiral-wound retaining rings quickly, reliably, and safely. Tool inserts rings in splined or irregularly shaped bores, bores at bottom of deep ring and slides it along bore until it nests in groove. Pistons are moved by variety of linkages.

  10. Multi-stage FE simulation of hot ring rolling

    NASA Astrophysics Data System (ADS)

    Wang, C.; Geijselaers, H. J. M.; van den Boogaard, A. H.

    2013-05-01

    As a unique and important member of the metal forming family, ring rolling provides a cost effective process route to manufacture seamless rings. Applications of ring rolling cover a wide range of products in aerospace, automotive and civil engineering industries [1]. Above the recrystallization temperature of the material, hot ring rolling begins with the upsetting of the billet cut from raw stock. Next a punch pierces the hot upset billet to form a hole through the billet. This billet, referred to as preform, is then rolled by the ring rolling mill. For an accurate simulation of hot ring rolling, it is crucial to include the deformations, stresses and strains from the upsetting and piercing process as initial conditions for the rolling stage. In this work, multi-stage FE simulations of hot ring rolling process were performed by mapping the local deformation state of the workpiece from one step to the next one. The simulations of upsetting and piercing stages were carried out by 2D axisymmetric models using adaptive remeshing and element erosion. The workpiece for the ring rolling stage was subsequently obtained after performing a 2D to 3D mapping. The commercial FE package LS-DYNA was used for the study and user defined subroutines were implemented to complete the control algorithm. The simulation results were analyzed and also compared with those from the single-stage FE model of hot ring rolling.

  11. Thermodynamic black di-rings

    SciTech Connect

    Iguchi, Hideo; Mishima, Takashi

    2010-10-15

    Previously the five dimensional S{sup 1}-rotating black rings have been superposed in a concentric way by some solitonic methods, and regular systems of two S{sup 1}-rotating black rings were constructed by the authors and then Evslin and Krishnan (we called these solutions 'black di-rings'). In this place we show some characteristics of the solutions of five dimensional black di-rings, especially in thermodynamic equilibrium. After the summary of the di-ring expressions and their physical quantities, first we comment on the equivalence of the two different solution sets of the black di-rings. Then the existence of thermodynamic black di-rings is shown, in which both isothermality and isorotation between the inner black ring and the outer black ring are realized. We also give detailed analysis of peculiar properties of the thermodynamic black di-ring including discussion about a certain kind of thermodynamic stability (instability) of the system.

  12. Propellers in Saturn's rings

    NASA Astrophysics Data System (ADS)

    Sremcevic, M.; Stewart, G. R.; Albers, N.; Esposito, L. W.

    2013-12-01

    Theoretical studies and simulations have demonstrated the effects caused by objects embedded in planetary rings. Even if the objects are too small to be directly observed, each creates a much larger gravitational imprint on the surrounding ring material. These strongly depend on the mass of the object and range from "S" like propeller-shaped structures for about 100m-sized icy bodies to the opening of circumferential gaps as in the case of the embedded moons Pan and Daphnis and their corresponding Encke and Keeler Gaps. Since the beginning of the Cassini mission many of these smaller objects (~<500m in size) have been indirectly identified in Saturn's A ring through their propeller signature in the images. Furthermore, recent Cassini observations indicate the possible existence of objects embedded even in Saturn's B and C ring. In this paper we present evidence for the existence of propellers in Saturn's B ring by combining data from Cassini Ultraviolet Imaging Spectrograph (UVIS) and Imaging Science Subsystem (ISS) experiments. We show evidence that B ring seems to harbor two distinct populations of propellers: "big" propellers covering tens of degrees in azimuth situated in the densest part of B ring, and "small" propellers in less dense inner B ring that are similar in size and shape to known A ring propellers. The population of "big" propellers is exemplified with a single object which is observed for 5 years of Cassini data. The object is seen as a very elongated bright stripe (40 degrees wide) in unlit Cassini images, and dark stripe in lit geometries. In total we report observing the feature in images at 18 different epochs between 2005 and 2010. In UVIS occultations we observe this feature as an optical depth depletion in 14 out of 93 occultation cuts at corrotating longitudes compatible with imaging data. Combining the available Cassini data we infer that the object is a partial gap located at r=112,921km embedded in the high optical depth region of the B

  13. Mapping Ring Particle Cooling across Saturn's Rings with Cassini CIRS

    NASA Astrophysics Data System (ADS)

    Brooks, Shawn M.; Spilker, L. J.; Edgington, S. G.; Pilorz, S. H.; Deau, E.

    2010-10-01

    Previous studies have shown that the rings' thermal inertia, a measure of their response to changes in the thermal environment, varies from ring to ring. Thermal inertia can provide insight into the physical structure of Saturn's ring particles and their regoliths. Low thermal inertia and quick temperature responses are suggestive of ring particles that have more porous or fluffy regoliths or that are riddled with cracks. Solid, coherent particles can be expected to have higher thermal inertias (Ferrari et al. 2005). Cassini's Composite Infrared Spectrometer has recorded millions of spectra of Saturn's rings since its arrival at Saturn in 2004 (personal communication, M. Segura). CIRS records far infrared radiation between 10 and 600 cm-1 (16.7 and 1000 µm) at focal plane 1 (FP1), which has a field of view of 3.9 mrad. Thermal emission from Saturn's rings peaks in this wavelength range. FP1 spectra can be used to infer ring temperatures. By tracking how ring temperatures vary, we can determine the thermal inertia of the rings. In this work we focus on CIRS observations of the shadowed portion of Saturn's rings. The thermal budget of the rings is dominated by the solar radiation absorbed by its constituent particles. When ring particles enter Saturn's shadow this source of energy is abruptly cut off. As a result, ring particles cool as they traverse Saturn's shadow. From these shadow observations we can create cooling curves at specific locations across the rings. We will show that the rings' cooling curves and thus their thermal inertia vary not only from ring to ring, but by location within the individual rings. This research was carried out at the Jet Propulsion Laboratory, California Institute of Technology, under contract with NASA. Copyright 2010 California Institute of Technology. Government sponsorship acknowledged.

  14. Calculating Ring Pucker Free Energy Surfaces From Reaction Coordinate Forces

    SciTech Connect

    Barnett, Christopher B.; Naidoo, Kevin J.

    2009-03-09

    We implemented the free energy from adaptive reaction coordinate forces (FEARCF) method and applied it to the conformational investigation of carbohydrate ring puckering. The method allows for significantly enhanced sampling of reaction coordinate space. The free energies associated with the ring pucker motion of {beta}-D-ribose (a furanose) and {beta}-D-glucose (a pyranose) were calculated. These can be used to interpret catalytic mechanisms of glycosylases.

  15. Saturn's Other Ring Current

    NASA Astrophysics Data System (ADS)

    Crary, F. J.

    2014-04-01

    Saturn's main rings orbit the planet within an atmosphere and ionosphere of water, oxygen and hydrogen, produced by meteoritic impacts on and ultraviolet photodesorbtion of the ring particles [Johnson et al., 2006; Luhmann et al., 2006; Tseng et al., 2010]. The neutral atmosphere itself has only been tentatively detected through ultraviolet fluorescents of OH [Hall et al., 1996] while the ionosphere was observed in situ by the Cassini spacecraft shortly after orbital insertion [Coates et al.,2005; Tokar et al. 2005, Waite et al. 2005]. Although the plasma flow velocity of this ionosphere is not well-constrained, but the close association with the rings suggests that its speed would be couppled to the keplarian velocity of the rings themselves. As a result, the motion of the plasma through Saturn's magnetic field would produce an induced voltage, oriented away from the planet outside synchronous orbit and towards the planet inside synchronous orbit. Such a potential could result in currents flowing across the ring plane and closeing along magnetic field lines and through Saturn's ionosphere at latitudes between 36o and 48o. Cassini observations of whistler-mode plasma wave emissions [Xin et al.,2006] centered on synchronous orbit (1.76 Rs, mapping to 41o latitude) have been interpreted as a product of field-aligned electron beams associated with such a current. This presentation will investigate the magnitude of these currents and the resulting Joule heating of the ionosphere. An important constraint is that no auroral ultraviolet emissions have been observed at the relevant latitudes. In contrast, Joule heating could affect infrared emissions from H3+. Variations in H3+ emission associated with Saturn's rings have been reported by O'Donoghue et al., 2013, and interpreted as a result of ring "rain", i.e. precipitating water group species from the rings which alter ionosphereic chemistry and H3+ densities. As noted by O'Donoghue et al., this interpretation may be

  16. Piston Ring Pressure Distribution

    NASA Technical Reports Server (NTRS)

    Kuhn, M.

    1943-01-01

    The discovery and introduction of the internal combustion engine has resulted in a very rapid development in machines utilizing the action of a piston. Design has been limited by the internal components of the engine, which has been subjected to ever increasing thermal and mechanical stresses, Of these internal engine components, the piston and piston rings are of particular importance and the momentary position of engine development is not seldom dependent upon the development of both of the components, The piston ring is a well-known component and has been used in its present shape in the steam engine of the last century, Corresponding to its importance, the piston ring has been a rich field for creative activity and it is noteworthy that in spite of this the ring has maintained its shape through the many years. From the many and complicated designs which have been suggested as a packing between piston and cylinder wall hardly one suggestion has remained which does not resemble the original design of cast iron rectangular ring.

  17. Stacked Corrugated Horn Rings

    NASA Technical Reports Server (NTRS)

    Sosnowski, John B.

    2010-01-01

    This Brief describes a method of machining and assembly when the depth of corrugations far exceeds the width and conventional machining is not practical. The horn is divided into easily machined, individual rings with shoulders to control the depth. In this specific instance, each of the corrugations is identical in profile, and only differs in diameter and outer profile. The horn is segmented into rings that are cut with an interference fit (zero clearance with all machining errors biased toward contact). The interference faces can be cut with a reverse taper to increase the holding strength of the joint. The taper is a compromise between the interference fit and the clearance of the two faces during assembly. Each internal ring is dipped in liquid nitrogen, then nested in the previous, larger ring. The ring is rotated in the nest until the temperature of the two parts equalizes and the pieces lock together. The resulting assay is stable, strong, and has an internal finish that cannot be achieved through other methods.

  18. Two F Ring Views

    NASA Technical Reports Server (NTRS)

    2005-01-01

    These views, taken two hours apart, demonstrate the dramatic variability in the structure of Saturn's intriguing F ring.

    In the image at the left, ringlets in the F ring and Encke Gap display distinctive kinks, and there is a bright patch of material on the F ring's inner edge. Saturn's moon Janus (181 kilometers, or 113 miles across) is shown here, partly illuminated by reflected light from the planet.

    At the right, Prometheus (102 kilometers, or 63 miles across) orbits ahead of the radial striations in the F ring, called 'drapes' by scientists. The drapes appear to be caused by successive passes of Prometheus as it reaches the greatest distance (apoapse) in its orbit of Saturn. Also in this image, the outermost ringlet visible in the Encke Gap displays distinctive bright patches.

    These views were obtained from about three degrees below the ring plane.

    The images were taken in visible light with the Cassini spacecraft narrow-angle camera on June 29, 2005, when Cassini was about 1.5 million kilometers (900,000 miles) from Saturn. The image scale is about 9 kilometers (6 miles) per pixel.

  19. Pressure Dependence of Insulator-Insulator Contact Charging

    NASA Technical Reports Server (NTRS)

    Hogue, Michael D.

    2005-01-01

    The mechanism of insulator-insulator triboelectric (contact) charging is being studied by the Electrostatics and Surface Physics Laboratory at KSC. The hypothesis that surface ion exchange is the primary mechanism is being tested experimentally. A two-phase model based on a small partial pressure of singly charged ions in an ambient ideal gas in equilibrium with a submonolayer adsorbed film will provide predictions about charging as a function Of ion mass, pressure, temperature, and surface adsorption energy. Interactions between ions will be considered in terms of coulombic and screened potential energies. This work is yielding better understanding of the triboelectrification of insulators, which is an important problem in. space exploration technology. The work is also relevant to important industrial processes such as xerography and the application of paints and coatings. Determining a better understanding of the fundamental mechanism of insulator-insulator triboelectrification will hopefully lead to better means of eliminating or at least mitigating its hazards and enhancing its useful applications.

  20. Rings in the solar system

    SciTech Connect

    Pollack, J.B.; Cuzzi, J.N.

    1981-11-01

    Saturn, Jupiter, and Uranus have rings with different structure and composition. The rings consist of tiny masses in independent orbits. Photographs and data obtained by the Voyager project have aided in the understanding of Saturn's rings. Spokes have been found in B ring and boards, knots, and twist in F ring. Particles on the order of a micrometer in size are believed to occur in F, B, and A rings. The dominant component is water ice. The rings of Uranus are narrow and separated by broad empty regions. The technique used to study them has been stellar occulation. Nothing is known of particle size. The dominant component is believed to be silicates rich in compounds that absorb sunlight. Jupiter's rings consist of 3 main parts: a bright ring, a diffuse disk, and a halo. Use of Pioneer 10 data and other techniques have indicated particle sizes on the order of several micrometers and some at least a centimeter in diameter. The architecture of the ring system results from the interplay of a number of forces. These include gravitational forces due to moons outside the rings and moonlets embedded in them, electromagnetic forces due to the planet's rotating magnetic field, and even the gentle forces exerted by the dilute gaseous medium in which the rings rotate. Each of these forces is discussed. Several alternative explanations of how the rings arose are considered. The primary difference in these hypotheses is the account of the relationship between the ring particles of today and the primordial ring material. (SC)

  1. Physics of planetary rings

    NASA Astrophysics Data System (ADS)

    Gorkavyi, N.

    2007-08-01

    It is difficult to enumerate all the surprises presented by the planetary rings. The Saturnian rings are stratified into thousands of ringlets and the Uranian rings are compressed into narrow streams, which for some reason or other differ from circular orbits like the wheel of an old bicycle. The edge of the rings is jagged and the rings themselves are pegged down under the gravitational pressure of the satellites, bending like a ship's wake. There are spiral waves, elliptical rings, strange interlacing of narrow ringlets, and to cap it all one has observed in the Neptunian ring system three dense, bright arcs - like bunches of sausages on a transparent string. For celestial mechanics this is a spectacle as unnatural as a bear's tooth in the necklace of the English queen. In the dynamics of planetary rings the physics of collective interaction was supplemented by taking collisions between particles into account. One was led to study a kinetic equation with a rather complex collision integral - because the collisions are inelastic - which later on made it possible, both by using the Chapman-Enskog method and by using the solution of the kinetic equation for a plasma in a magnetic field, to reduce it to a closed set of (hydrodynamical) moment equations [1]. The hydrodynamical instabilities lead to the growth of short-wavelength waves and large-scale structures of the Saturnian rings [1]. We have shown that the formation of the existing dense Uranian rings is connected with the capture of positively drifting ring particles in inner Lindblad resonances which arrest this drift [1]. After the formation of dense rings at the positions of satellite resonances the collective interaction between resonant particles is amplified and the rings can leave the resonance and drift away from the planet and the parent resonance. We can expect in the C ring an appreciable positive ballistic particle drift caused by the erosion of the B ring by micrometeorites. It is therefore natural

  2. A photonic crystal ring resonator formed by SOI nano-rods.

    PubMed

    Chiu, Wei-Yu; Huang, Tai-Wei; Wu, Yen-Hsiang; Chan, Yi-Jen; Hou, Chia-Hunag; Chien, Huang Ta; Chen, Chii-Chang

    2007-11-12

    The design, fabrication and measurement of a silicon-on-insulator (SOI) two-dimensional photonic crystal ring resonator are demonstrated in this study. The structure of the photonic crystal is comprised of silicon nano-rods arranged in a hexagonal lattice on an SOI wafer. The photonic crystal ring resonator allows for the simultaneous separation of light at wavelengths of 1.31 and 1.55mum. The device is fabricated by e-beam lithography. The measurement results confirm that a 1.31mum/1.55mum wavelength ring resonator filter with a nano-rod photonic crystal structure can be realized. PMID:19550835

  3. Double Ring Craters

    NASA Technical Reports Server (NTRS)

    1974-01-01

    A faint double ring crater is seen at upper right in this picture of Mercury (FDS 166601) taken one hour and 40 minutes before Mariner 10's second rendezvous with the planet September 21. Located 35 degrees S. Lat. The outer ring is 170 kilometers (10 miles) across. Double ring craters are common features on Mercury. This particular feature and the bright rayed crater to its left were seen from a different viewing angle in pictures taken by Mariner 10 during its first Mercury flyby last March 29.

    The Mariner 10 mission, managed by the Jet Propulsion Laboratory for NASA's Office of Space Science, explored Venus in February 1974 on the way to three encounters with Mercury-in March and September 1974 and in March 1975. The spacecraft took more than 7,000 photos of Mercury, Venus, the Earth and the Moon.

    Image Credit: NASA/JPL/Northwestern University

  4. Deployable Fresnel Rings

    NASA Technical Reports Server (NTRS)

    Kennedy, Timothy F.; Fink, Patrick W.; Chu, Andrew W.; Lin, Gregory Y.

    2014-01-01

    Deployable Fresnel rings (DFRs) significantly enhance the realizable gain of an antenna. This innovation is intended to be used in combination with another antenna element, as the DFR itself acts as a focusing or microwave lens element for a primary antenna. This method is completely passive, and is also completely wireless in that it requires neither a cable, nor a connector from the antenna port of the primary antenna to the DFR. The technology improves upon the previous NASA technology called a Tri-Sector Deployable Array Antenna in at least three critical aspects. In contrast to the previous technology, this innovation requires no connector, cable, or other physical interface to the primary communication radio or sensor device. The achievable improvement in terms of antenna gain is significantly higher than has been achieved with the previous technology. Also, where previous embodiments of the Tri-Sector antenna have been constructed with combinations of conventional (e.g., printed circuit board) and conductive fabric materials, this innovation is realized using only conductive and non-conductive fabric (i.e., "e-textile") materials, with the possible exception of a spring-like deployment ring. Conceptually, a DFR operates by canceling the out-of-phase radiation at a plane by insertion of a conducting ring or rings of a specific size and distance from the source antenna, defined by Fresnel zones. Design of DFRs follow similar procedures to those outlined for conventional Fresnel zone rings. Gain enhancement using a single ring is verified experimentally and through computational simulation. The experimental test setup involves a microstrip patch antenna that is directly behind a single-ring DFR and is radiating towards a second microstrip patch antenna. The first patch antenna and DFR are shown. At 2.42 GHz, the DFR improves the transmit antenna gain by 8.6 dB, as shown in Figure 2, relative to the wireless link without the DFR. A figure illustrates the

  5. Oligomeric ferrocene rings

    NASA Astrophysics Data System (ADS)

    Inkpen, Michael S.; Scheerer, Stefan; Linseis, Michael; White, Andrew J. P.; Winter, Rainer F.; Albrecht, Tim; Long, Nicholas J.

    2016-09-01

    Cyclic oligomers comprising strongly interacting redox-active monomer units represent an unknown, yet highly desirable class of nanoscale materials. Here we describe the synthesis and properties of the first family of molecules belonging to this compound category—differently sized rings comprising only 1,1‧-disubstituted ferrocene units (cyclo[n], n = 5-7, 9). Due to the close proximity and connectivity of centres (covalent Cp-Cp linkages; Cp = cyclopentadienyl) solution voltammograms exhibit well-resolved, separated 1e- waves. Theoretical interrogations into correlations based on ring size and charge state are facilitated using values of the equilibrium potentials of these transitions, as well as their relative spacing. As the interaction free energies between the redox centres scale linearly with overall ring charge and in conjunction with fast intramolecular electron transfer (˜107 s-1), these molecules can be considered as uniformly charged nanorings (diameter ˜1-2 nm).

  6. Oligomeric ferrocene rings

    NASA Astrophysics Data System (ADS)

    Inkpen, Michael S.; Scheerer, Stefan; Linseis, Michael; White, Andrew J. P.; Winter, Rainer F.; Albrecht, Tim; Long, Nicholas J.

    2016-09-01

    Cyclic oligomers comprising strongly interacting redox-active monomer units represent an unknown, yet highly desirable class of nanoscale materials. Here we describe the synthesis and properties of the first family of molecules belonging to this compound category—differently sized rings comprising only 1,1‧-disubstituted ferrocene units (cyclo[n], n = 5–7, 9). Due to the close proximity and connectivity of centres (covalent Cp–Cp linkages; Cp = cyclopentadienyl) solution voltammograms exhibit well-resolved, separated 1e– waves. Theoretical interrogations into correlations based on ring size and charge state are facilitated using values of the equilibrium potentials of these transitions, as well as their relative spacing. As the interaction free energies between the redox centres scale linearly with overall ring charge and in conjunction with fast intramolecular electron transfer (∼107 s‑1), these molecules can be considered as uniformly charged nanorings (diameter ∼1–2 nm).

  7. Child sex rings.

    PubMed

    Wild, N J; Wynne, J M

    1986-07-19

    Details of 11 child sex rings identified in one working class community were obtained by interviewing investigating police officers and examining health and social services records. The rings contained 14 adult male perpetrators and 175 children aged 6-15 years. Most perpetrators used child ringleaders to recruit victims; others became a "family friend" or obtained a position of authority over children. Secrecy was encouraged and bribery, threats, and peer pressure used to induce participation in sexual activities. Offences reported included fondling, masturbation, pornography, and oral, vaginal, and anal intercourse. Eleven perpetrators were successfully prosecuted; all but one received a sentence of three years or less. Behavioural problems were common among those children who had participated for a long time. Child sex rings are difficult to detect and may be common. Many children are seriously abused as a consequence of them. PMID:3730803

  8. Rings dominate western Gulf

    NASA Astrophysics Data System (ADS)

    Vidal L., Francisco V.; Vidal L., Victor M. V.; Molero, José María Pérez

    Surface and deep circulation of the central and western Gulf of Mexico is controlled by interactions of rings of water pinched from the gulf's Loop Current. The discovery was made by Mexican oceanographers who are preparing a full-color, 8-volume oceanographic atlas of the gulf.Anticyclonic warm-core rings pinch off the Loop Current at a rate of about one to two per year, the scientists of the Grupo de Estudios Oceanográficos of the Instituto de Investigaciones Eléctricas (GEO-IIE) found. The rings migrate west until they collide with the continental shelf break of the western gulf, almost always between 22° and 23°N latitude. On their westward travel they transfer angular momentum and vorticity to the surrounding water, generating cyclonic circulations and vortex pairs that completely dominate the entire surface and deep circulation of the central and western gulf.

  9. Sliding-Ring Catenanes.

    PubMed

    Fernando, Isurika R; Frasconi, Marco; Wu, Yilei; Liu, Wei-Guang; Wasielewski, Michael R; Goddard, William A; Stoddart, J Fraser

    2016-08-17

    Template-directed protocols provide a routine approach to the synthesis of mechanically interlocked molecules (MIMs), in which the mechanical bonds are stabilized by a wide variety of weak interactions. In this Article, we describe a strategy for the preparation of neutral [2]catenanes with sliding interlocked electron-rich rings, starting from two degenerate donor-acceptor [2]catenanes, consisting of a tetracationic cyclobis(paraquat-p-phenylene) cyclophane (CBPQT(4+)) and crown ethers containing either (i) hydroquinone (HQ) or (ii) 1,5-dioxynaphthalene (DNP) recognition units and carrying out four-electron reductions of the cyclophane components to their neutral forms. The donor-acceptor interactions between the CBPQT(4+) ring and both HQ and DNP units present in the crown ethers that stabilize the [2]catenanes are weakened upon reduction of the cyclophane components to their radical cationic states and are all but absent in their fully reduced states. Characterization in solution performed by UV-vis, EPR, and NMR spectroscopic probes reveals that changes in the redox properties of the [2]catenanes result in a substantial decrease of the energy barriers for the circumrotation and pirouetting motions of the interlocked rings, which glide freely through one another in the neutral states. The solid-state structures of the fully reduced catenanes reveal profound changes in the relative dispositions of the interlocked rings, with the glycol chains of the crown ethers residing in the cavities of the neutral CBPQT(0) rings. Quantum mechanical investigations of the energy levels associated with the four different oxidation states of the catenanes support this interpretation. Catenanes and rotaxanes with sliding rings are expected to display unique properties. PMID:27398609

  10. Flashover tests of artificially iced insulators

    SciTech Connect

    Charneski, M.D.; Gaibrois, G.L.; Whitney, B.F.

    1982-08-01

    Test apparatus and procedures were developed to test energized, non-contaminated, 120 kV system insulators under simulated freezing rain conditions. The flashover performances were compared between non-ceramic composite transmission line insulators and standard porcelain 5 3/4 x 10 inch suspension insulators. Standard and long leak Multicone porcelain insulators were also compared in the icing tests to standard porcelain station post insulators. Icing tests at several voltage stresses provided the full flashover range of the insulators from the minimum or zero flashovers in ten trials up to the maximum or 10 flashovers in 10 trials. Using the desired insulator voltage stress flashover curve for specific insulator types and the voltage stress applied to the insulator, the comparative probability of flashover due to ice storms on the system can be evaluated for 120 kV, 230 kV and 345 kV systems.

  11. Ring laser gyroscope anode

    SciTech Connect

    Ljung, B.H.

    1981-03-17

    An anode for a ring laser gyroscope which provides improved current stability in the glow discharge path is disclosed. The anode of this invention permits operation at lower currents thereby allowing a reduction of heat dissipation in the ring laser gyroscope. The anode of one embodiment of this invention is characterized by a thumbtack appearance with a spherical end where the normal sharp end of the thumbtack would be located. The stem of the anode extends from the outside of the gyroscope structure to the interior of the structure such that the spherical end is substantially adjacent to the laser beam.

  12. The covariant chiral ring

    NASA Astrophysics Data System (ADS)

    Bourget, Antoine; Troost, Jan

    2016-03-01

    We construct a covariant generating function for the spectrum of chiral primaries of symmetric orbifold conformal field theories with N = (4 , 4) supersymmetry in two dimensions. For seed target spaces K3 and T 4, the generating functions capture the SO(21) and SO(5) representation theoretic content of the chiral ring respectively. Via string dualities, we relate the transformation properties of the chiral ring under these isometries of the moduli space to the Lorentz covariance of perturbative string partition functions in flat space.

  13. GUARD RING SEMICONDUCTOR JUNCTION

    DOEpatents

    Goulding, F.S.; Hansen, W.L.

    1963-12-01

    A semiconductor diode having a very low noise characteristic when used under reverse bias is described. Surface leakage currents, which in conventional diodes greatly contribute to noise, are prevented from mixing with the desired signal currents. A p-n junction is formed with a thin layer of heavily doped semiconductor material disposed on a lightly doped, physically thick base material. An annular groove cuts through the thin layer and into the base for a short distance, dividing the thin layer into a peripheral guard ring that encircles the central region. Noise signal currents are shunted through the guard ring, leaving the central region free from such currents. (AEC)

  14. Unidirectional ring lasers

    DOEpatents

    Hohimer, John P.; Craft, David C.

    1994-01-01

    Unidirectional ring lasers formed by integrating nonreciprocal optical elements into the resonant ring cavity. These optical elements either attenuate light traveling in a nonpreferred direction or amplify light traveling in a preferred direction. In one preferred embodiment the resonant cavity takes the form of a circle with an S-shaped crossover waveguide connected to two points on the interior of the cavity such that light traveling in a nonpreferred direction is diverted from the cavity into the crossover waveguide and reinjected out of the other end of the crossover waveguide into the cavity as light traveling in the preferred direction.

  15. Unidirectional ring lasers

    DOEpatents

    Hohimer, J.P.; Craft, D.C.

    1994-09-20

    Unidirectional ring lasers formed by integrating nonreciprocal optical elements into the resonant ring cavity is disclosed. These optical elements either attenuate light traveling in a nonpreferred direction or amplify light traveling in a preferred direction. In one preferred embodiment the resonant cavity takes the form of a circle with an S-shaped crossover waveguide connected to two points on the interior of the cavity such that light traveling in a nonpreferred direction is diverted from the cavity into the crossover waveguide and reinjected out of the other end of the crossover waveguide into the cavity as light traveling in the preferred direction. 21 figs.

  16. Saturn's Rings, the Yarkovsky Effects, and the Ring of Fire

    NASA Technical Reports Server (NTRS)

    Rubincam, David Parry

    2004-01-01

    The dimensions of Saturn's A and B rings may be determined by the seasonal Yarkovsky effect and the Yarkovsky-Schach effect; the two effects confine the rings between approximately 1.68 and approximately 2.23 Saturn radii, in reasonable agreement with the observed values of 1.525 and 2.267. The C ring may be sparsely populated because its particles are transients on their way to Saturn; the infall may create a luminous Ring of Fire around Saturn's equator. The ring system may be young: in the past heat flow from Saturn's interior much above its present value would not permit rings to exist.

  17. Enhanced rectifying response from metal-insulator-insulator-metal junctions

    NASA Astrophysics Data System (ADS)

    Maraghechi, P.; Foroughi-Abari, A.; Cadien, K.; Elezzabi, A. Y.

    2011-12-01

    We present on a metal-insulator-insulator-metal quantum electronic tunneling devices suitable for high speed rectifiers. Through the introduction of double oxide layer between similar metallic electrodes, a cascaded potential barrier is formed which alters the electron tunneling mechanism at forward versus the reverse bias. The cascaded potential barrier engineering manifests itself in both a highly nonlinear and asymmetric I-V junction characteristic. It is envisioned that high speed rectifiers and mixers having extraordinary nonlinearity can be realized through the incorporation of the cascaded potential barrier architecture and dissimilar metallic electrodes.

  18. Proximity effects in a topological-insulator/Mott-insulator heterostructure

    NASA Astrophysics Data System (ADS)

    Ueda, Suguru; Kawakami, Norio; Sigrist, Manfred

    2013-04-01

    We investigate proximity effects in a correlated heterostructure of a two-dimensional Mott insulator (MI) and a topological insulator (TI) by employing inhomogeneous dynamical mean-field theory. We show that the edge state of the TI induces strongly renormalized midgap states inside the MI region, which still have a remnant of the helical energy spectrum. The penetration of low-energy electrons, which is controlled by the interface tunneling V, largely enhances the electron mass inside the MI and also splits a single Dirac cone at edge sites into the spatially separated two Dirac cones in the strong V region.

  19. Prediscovery evidence of planetary rings

    NASA Technical Reports Server (NTRS)

    Mclaughlin, W. I.

    1980-01-01

    The discoveries of the Uranian and Jovian ring systems were surprising events to most of the scientific community. However, as far back as 1787 reports of observations of rings about a planet other than Saturn were made; Herschel, the discoverer of Uranus, thought he had detected rings about that planet on several occasions. Although Herschel's observations were almost certainly due to defects in the optical system of his telescope, several valid observations and predictions have been made in the last two hundred years. This paper focuses on such prediscovery evidence for the Uranian and Jovian rings and for the newly designated F ring of Saturn. Some new work of the author on the structure of the Saturnian rings is included which is relevant to the F ring. The prospects for rings about Neptune and Pluto and a ring close to the Sun are also reviewed. The relevance of the prediscovery evidence to aspects of scientific methodology is discussed.

  20. Flushing Ring for EDM

    NASA Technical Reports Server (NTRS)

    Earwood, L.

    1985-01-01

    Removing debris more quickly lowers cutting time. Operation, cutting oil and pressurized air supplied to ring placed around workpiece. Air forces oil through small holes and agitates oil as it flows over workpiece. High flow rate and agitation dislodge and remove debris. Electrical discharge removes material from workpiece faster.

  1. Ring of Stellar Death

    NASA Technical Reports Server (NTRS)

    2004-01-01

    This false-color image from NASA's Spitzer Space Telescope shows a dying star (center) surrounded by a cloud of glowing gas and dust. Thanks to Spitzer's dust-piercing infrared eyes, the new image also highlights a never-before-seen feature -- a giant ring of material (red) slightly offset from the cloud's core. This clumpy ring consists of material that was expelled from the aging star.

    The star and its cloud halo constitute a 'planetary nebula' called NGC 246. When a star like our own Sun begins to run out of fuel, its core shrinks and heats up, boiling off the star's outer layers. Leftover material shoots outward, expanding in shells around the star. This ejected material is then bombarded with ultraviolet light from the central star's fiery surface, producing huge, glowing clouds -- planetary nebulas -- that look like giant jellyfish in space.

    In this image, the expelled gases appear green, and the ring of expelled material appears red. Astronomers believe the ring is likely made of hydrogen molecules that were ejected from the star in the form of atoms, then cooled to make hydrogen pairs. The new data will help explain how planetary nebulas take shape, and how they nourish future generations of stars.

    This image composite was taken on Dec. 6, 2003, by Spitzer's infrared array camera, and is composed of images obtained at four wavelengths: 3.6 microns (blue), 4.5 microns (green), 5.8 microns (orange) and 8 microns (red).

  2. Reading, Writing, and Rings!

    ERIC Educational Resources Information Center

    Aschbacher, Pamela; Li, Erika; Hammon, Art

    2008-01-01

    "Reading, Writing, and Rings!" was created by a team of elementary teachers, literacy experts, and scientists in order to integrate science and literacy. These free units bring students inside NASA's Cassini-Huygens mission to Saturn. The authors--a science teacher and education outreach specialist and two evaluators of educational programs--have…

  3. Ring laser scatterometer

    SciTech Connect

    Ackermann, Mark; Diels, Jean-Claude

    2005-06-28

    A scatterometer utilizes the dead zone resulting from lockup caused by scatter from a sample located in the optical path of a ring laser at a location where counter-rotating pulses cross. The frequency of one pulse relative to the other is varied across the lockup dead zone.

  4. Making Molecular Borromean Rings

    ERIC Educational Resources Information Center

    Pentecost, Cari D.; Tangchaivang, Nichol; Cantrill, Stuart J.; Chichak, Kelly S.; Peters, Andrea J.; Stoddart, Fraser J.

    2007-01-01

    A procedure that requires seven 4-hour blocks of time to allow undergraduate students to prepare the molecular Borromean rings (BRs) on a gram-scale in 90% yield is described. The experiment would serve as a nice capstone project to culminate any comprehensive organic laboratory course and expose students to fundamental concepts, symmetry point…

  5. Floquet topological insulators for sound.

    PubMed

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

    2016-06-17

    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.

  6. Thermal shock resistance ceramic insulator

    DOEpatents

    Morgan, Chester S.; Johnson, William R.

    1980-01-01

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

  7. Process for making ceramic insulation

    SciTech Connect

    Akash, Akash; Balakrishnan, G. Nair

    2009-12-08

    A method is provided for producing insulation materials and insulation for high temperature applications using novel castable and powder-based ceramics. The ceramic components produced using the proposed process offers (i) a fine porosity (from nano-to micro scale); (ii) a superior strength-to-weight ratio; and (iii) flexibility in designing multilayered features offering multifunctionality which will increase the service lifetime of insulation and refractory components used in the solid oxide fuel cell, direct carbon fuel cell, furnace, metal melting, glass, chemical, paper/pulp, automobile, industrial heating, coal, and power generation industries. Further, the ceramic components made using this method may have net-shape and/or net-size advantages with minimum post machining requirements.

  8. Floquet topological insulators for sound

    PubMed Central

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

    2016-01-01

    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. PMID:27312175

  9. Floquet topological insulators for sound.

    PubMed

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

    2016-01-01

    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. PMID:27312175

  10. Floquet topological insulators for sound

    NASA Astrophysics Data System (ADS)

    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.

  11. Neptune may have polar rings

    NASA Astrophysics Data System (ADS)

    Dobrovolskis, A. R.; Steiman-Cameron, T. Y.; Borderies, N. J.

    1989-08-01

    Perturbations from Neptune's highly inclined satellite Triton can maintain rings passing nearly over Neptune's poles. These hypothetical polar rings are nearly perpendicular to Triton's orbit as well, and lie within several degrees of the plane of Voyager II's trajectory through the Neptunian system. Polar rings can coexist with equatorial rings at different radii. A randomly oriented torus of debris around Neptune has a probability of several percent to settle into a polar ring. Voyager II stands a significant chance of encountering a polar ring.

  12. Narrow rings - Observations and theory

    NASA Astrophysics Data System (ADS)

    Porco, C. C.

    Voyager 1 and 2 observations have revealed that within the rings of Saturn lies a set of narrow, eccentric rings resembling those of Uranus. Voyager 2 observations have proven crucial in refining the Uranian ring orbit models to a remarkable level of precision. All these rings share some common structural and kinematical characteristics, such as spatially variable radial widths and uniform precession; however, interesting differences exist which provoke attention and may be related to the differing dynamical environments in which these rings dwell. The current state of the knowledge of the shape, behavior, and confinement of narrow rings is discussed.

  13. Ring Bubbles of Dolphins

    NASA Technical Reports Server (NTRS)

    Shariff, Karim; Marten, Ken; Psarakos, Suchi; White, Don J.; Merriam, Marshal (Technical Monitor)

    1996-01-01

    The article discusses how dolphins create and play with three types of air-filled vortices. The underlying physics is discussed. Photographs and sketches illustrating the dolphin's actions and physics are presented. The dolphins engage in this behavior on their own initiative without food reward. These behaviors are done repeatedly and with singleminded effort. The first type is the ejection of bubbles which, after some practice on the part of the dolphin, turn into toroidal vortex ring bubbles by the mechanism of baroclinic torque. These bubbles grow in radius and become thinner as they rise vertically to the surface. One dolphin would blow two in succession and guide them to fuse into one. Physicists call this a vortex reconnection. In the second type, the dolphins first create an invisible vortex ring in the water by swimming on their side and waving their tail fin (also called flukes) vigorously. This vortex ring travels horizontally in the water. The dolphin then turns around, finds the vortex and injects a stream of air into it from its blowhole. The air "fills-out" the core of the vortex ring. Often, the dolphin would knock-off a smaller ring bubble from the larger ring (this also involves vortex reconnection) and steer the smaller ring around the tank. One other dolphin employed a few other techniques for planting air into the fluke vortex. One technique included standing vertically in the water with tail-up, head-down and tail piercing the free surface. As the fluke is waved to create the vortex ring, air is entrained from above the surface. Another technique was gulping air in the mouth, diving down, releasing air bubbles from the mouth and curling them into a ring when they rose to the level of the fluke. In the third type, demonstrated by only one dolphin, the longitudinal vortex created by the dorsal fin on the back is used to produce 10-15 foot long helical bubbles. In one technique she swims in a curved path. This creates a dorsal fin vortex since

  14. Rings from Close Encounters

    NASA Astrophysics Data System (ADS)

    Kohler, Susanna

    2016-09-01

    Weve recently discovered narrow sets of rings around two minor planets orbiting in our solar system. How did these rings form? A new study shows that they could be a result of close encounters between the minor planets and giants like Jupiter or Neptune.Unexpected Ring SystemsPositions of the centaurs in our solar system (green). Giant planets (red), Jupiter trojans (grey), scattered disk objects (tan) and Kuiper belt objects (blue) are also shown. [WilyD]Centaurs are minor planets in our solar system that orbit between Jupiter and Neptune. These bodies of which there are roughly 44,000 with diameters larger than 1 km have dynamically unstable orbits that cross paths with those of one or more giant planets.Recent occultation observations of two centaurs, 10199 Chariklo and 2060 Chiron, revealed that these bodies both host narrow ring systems. Besides our four giant planets, Chariklo and Chiron are the only other bodies in the solar system known to have rings. But how did these rings form?Scientists have proposed several models, implicating collisions, disruption of a primordial satellite, or dusty outgassing. But a team of scientists led by Ryuki Hyodo (Paris Institute of Earth Physics, Kobe University) has recently proposed an alternative scenario: what if the rings were formed from partial disruption of the centaur itself, after it crossed just a little too close to a giant planet?Tidal Forces from a GiantHyodo and collaborators first used past studies of centaur orbits to estimate that roughly 10% of centaurs experience close encounters (passing within a distance of ~2x the planetary radius) with a giant planet during their million-year lifetime. The team then performed a series of simulations of close encounters between a giant planet and a differentiated centaur a body in which the rocky material has sunk to form a dense silicate core, surrounded by an icy mantle.Some snapshots of simulation outcomes (click for a closer look!) for different initial states of

  15. A band-pass plasmonic filter with dual-square ring resonator

    NASA Astrophysics Data System (ADS)

    Duan, Gaoyan; Lang, Peilin; Wang, Lulu; Yu, Li; Xiao, Jinghua

    2014-09-01

    In this paper, we show the simulation of a plasmonic band-pass filter which consists of two surface plasmon polaritons (SPPs) waveguides and a resonator in metal-insulator-metal (MIM) structure. The resonator is formed by two square rings and a patch between them. The patch is a tiny rectangle cavity in order to transfer the SPPs from one ring to the other. The finite element method (FEM) method is employed in simulation. The results show that the dual-ring resonator performs better than a single ring does. The 3 dB bandwidth near the peak wavelength λ = 1054 nm is merely 31.7 nm. The resonant wavelength can be shifted by changing the side length of the square ring. This narrow band-pass filter is easy to fabricate and has potential applications in future integrated optical circuits.

  16. Demonstration of Microsphere Insulation in Cryogenic Vessels

    NASA Astrophysics Data System (ADS)

    Baumgartner, R. G.; Myers, E. A.; Fesmire, J. E.; Morris, D. L.; Sokalski, E. R.

    2006-04-01

    While microspheres have been recognized as a legitimate insulation material for decades, actual use in full-scale cryogenic storage tanks has not been demonstrated until now. The performance and life-cycle-cost advantages previously predicted have now been proven. Most bulk cryogenic storage tanks are insulated with either multilayer insulation (MLI) or perlite. Microsphere insulation, consisting of hollow glass bubbles, combines in a single material the desirable properties that other insulations only have individually. The material has high crush strength, low density, is noncombustible, and performs well in soft vacuum. These properties were proven during recent field testing of two 22,700-L (6,000-gallon) liquid nitrogen tanks, one insulated with microsphere insulation and the other with perlite. Normal evaporation rates (NER) for both tanks were monitored with precision test equipment and insulation levels within the tanks were observed through view ports as an indication of insulation compaction. Specific industrial applications were evaluated based on the test results and beneficial properties of microsphere insulation. Over-the-road trailers previously insulated with perlite will benefit not only from the reduced heat leak, but also the reduced mass of microsphere insulation. Economic assessments for microsphere-insulated cryogenic vessels including life-cycle cost are also presented.

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

    PubMed

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

    2012-09-24

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

  18. Aerogels Insulate Against Extreme Temperatures

    NASA Technical Reports Server (NTRS)

    2010-01-01

    In 1992, NASA started to pursue the development of aerogel for cryogenic insulation. Kennedy Space Center awarded Small Business Innovation Research (SBIR) contracts to Aspen Systems Inc., of Marlborough, Massachusetts, that resulted in a new manufacturing process and a new flexible, durable, easy-to-use form of aerogel. Aspen Systems formed Aspen Aerogels Inc., in Northborough, Massachusetts, to market the product, and by 2009, the company had become the leading provider of aerogel in the United States, producing nearly 20 million square feet per year. With an array of commercial applications, the NASA-derived aerogel has most recently been applied to protect and insulate people s hands and feet.

  19. On Charged Insulated Metallic Clusters

    NASA Astrophysics Data System (ADS)

    Dietrich, K.; Garny, M.; Pomorski, K.

    We determine the wavefunctions and eigen-values of electrons bound to a positively charged mesoscopic metallic cluster covered by an insulating surface layer. The radius of the metal core and the thickness of the insulating surface layer are of the order of a couple of Ångström. We study in particular the electromagnetic decay of externally located electrons into unoccupied internally located states which exhibits a resonance behaviour. This resonance structure has the consequence that the lifetime of the "mesoscopic atoms" may vary by up to 6 orders of magnitude depending on the values of the parameters (from sec to years).

  20. High temperature insulation barrier composite

    NASA Technical Reports Server (NTRS)

    Onstott, Joseph W. (Inventor)

    1989-01-01

    A composite material suitable for providing insulation for the nozzle structure of the Space Shuttle and other similar surfaces is disclosed. The composite layer is comprised of an outer skin layer of nickel chromium and an interleaved inner region comprising a top layer of nickel chromium foil which acts as a primary convective shield. There are at least two layers of alumina batting adjacent to the layers of silicon carbide fabric. An additional layer of nickel chromium foil is used as a secondary convective shield. The composite is particularly advantageous for use as nozzle insulation because of its ability to withstand high reentry temperatures, its flexibility, oxidation resistance, low conductivity, and light weight.

  1. Saturn ring temperature changes before and after ring equinox

    NASA Astrophysics Data System (ADS)

    Spilker, Linda; Flandes, Alberto; Morishima, Ryuji; Leyrat, Cedric; Altobelli, Nicolas; Ferrari, Cecile; Brooks, Shawn; Pilorz, Stu

    2010-05-01

    The Cassini Composite infrared spectrometer (CIRS) retrieved the temperatures of Saturn's main rings at solar elevations ranging from 24 degrees to zero degrees at equinox (August 2009) as the sun traversed from the south to north side of the rings. Over this broad range of solar elevation the CIRS data show that the ring temperatures vary as much as 29K- 38K for the A ring, 22K-34K for the B ring and 18K-23K for the C ring. Interestingly the unlit sides of the rings show a similar decrease in temperature with the decreasing solar elevation. As equinox approached, the main rings cooled to their lowest temperatures measured to date. At equinox the solar input is very small and the primary heat sources for the rings are Saturn thermal and visible energy. Temperatures are almost identical for similar geometries on the north and south sides of the rings. The ring temperatures at equinox were: C ring, 55-75 K; B ring, 45-60 K; Cassini Division, 45 - 58 K; and A ring, 43 - 52 K. After Saturn equinox the solar elevation angle began to increase again and the temperatures on both the lit (north) and unlit (south) sides of the rings have begun to increase as well. Ring thermal models developed by Flandes and Morishima are able to reproduce most of the equinox temperatures observed by CIRS. Results before and after equinox will be presented. This research was carried out at the Jet Propulsion Laboratory, California Institute of Technology, under contract with NASA and at CEA Saclay supported by the "Programme National de Planetologie". Copyright 2010 California Institute of Technology. Government sponsorship acknowledged.

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

    NASA Astrophysics Data System (ADS)

    Xu, Suyang

    2013-03-01

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

  3. Vacuum Packaging of MEMS With Multiple Internal Seal Rings

    NASA Technical Reports Server (NTRS)

    Hayworth, Ken; Yee, Karl; Shcheglov, Kirill; Bae, Youngsam; Wiberg, Dean; Peay, Chris; Challoner, Anthony

    2008-01-01

    A proposed method of design and fabrication of vacuum-packaged microelectromechanical systems (MEMS) and of individual microelectromechanical devices involves the use of multiple internal seal rings (MISRs) in conjunction with vias (through holes plated with metal for electrical contacts). The proposed method is compatible with mass production in a wafer-level fabrication process, in which the dozens of MEMS or individual microelectromechanical devices on a typical wafer are simultaneously vacuum packaged by bonding a capping wafer before the devices are singulated (cut apart by use of a dicing saw). In addition to being compatible with mass production, the proposed method would eliminate the need for some complex and expensive production steps and would yield more reliable vacuum seals. Conventionally, each MEMS or individual microelectromechanical device is fabricated as one of many identical units on a device wafer. Vacuum packaging is accomplished by bonding the device wafer to a capping wafer with metal seal rings (one ring surrounding each unit) that have been formed on the capping wafer. The electrical leads of each unit are laid out on what would otherwise be a flat surface of the device wafer, against which the seal ring is to be pressed for sealing. The resulting pattern of metal lines and their insulating oxide coverings presents a very rough and uneven surface, upon which it is difficult to pattern the sealing metal. Consequently, the seal is prone to leakage unless additional costly and complex planarization steps are performed before patterning the seal ring and bonding the wafers.

  4. EDITORIAL: Progress in topological insulators Progress in topological insulators

    NASA Astrophysics Data System (ADS)

    Morpurgo, Alberto; Trauzettel, Björn

    2012-12-01

    One of the most remarkable discoveries of the last few years in condensed matter physics is that the established distinction of crystalline solids in metals and insulators—which relies on the material band-structure—is incomplete. During the last several decades, the band structure of an uncountable variety of compounds of increasing complexity have been computed, and yet it has been overlooked that in the presence of sufficiently strong spin-orbit interaction, a new class of materials can be realized, that intrinsically behaves as insulators in their bulk and as metals at their surface. The discovery of this new class of materials was made only recently by Kane and Mele, during their theoretical studies of graphene in the presence of a sufficiently strong intrinsic spin-orbit interaction. Although the strength of the spin-orbit interaction in graphene is not sufficient to make the topological insulating state visible experimentally under currently reachable conditions, the validity and the originality of the concept were fully appreciated. Predictions for the occurrence of a two-dimensional topological insulating state in HgTe/CdTe heterostructures were made by Bernevig, Hughes and Zhang, and were followed by the experimental verification at Würzburg, in the Molenkamp group. Within a couple of years, this work brought the concept of topological insulator from an abstract theoretical discovery to an experimental reality, which stimulated further work. The concept of topological insulators was extended to the case of three-dimensional systems, for which an ideal experimental probe is angle-resolved photo-emission spectroscopy. Using this technique, specific theoretical predictions that had been made regarding the topological insulating character of different materials (e.g., for Bi-based compounds such as BiSb, Bi2Se3 or Bi2Te3), were verified experimentally through the direct observation of the Dirac surface fermions. This research was sufficient to put on

  5. Insulation board and process of making

    DOEpatents

    Nowobilski, Jeffert J.; Owens, William J.

    1985-01-01

    Insulation board capable of bearing a load without significant loss of insulating capacity due to compression, produced by a method wherein the board is made in compliance with specified conditions of time, temperature and pressure.

  6. New insulation constructions for aerospace wiring applications

    NASA Technical Reports Server (NTRS)

    Slenski, George

    1994-01-01

    Outlined in this presentation is the background to insulation constructions for aerospace wiring applications, the Air Force wiring policy, the purpose and contract requirements of new insulation constructions, the test plan, and the test results.

  7. Refractory thermal insulation for smooth metal surfaces

    NASA Technical Reports Server (NTRS)

    1964-01-01

    To protect rocket metal surfaces from engine exhaust heat, a refractory thermal insulation mixture, which adheres to smooth metals, has been developed. Insulation protection over a wide temperature range can be controlled by thickness of the applied mixture.

  8. Fiber Reinforced Composites for Insulation and Structures

    NASA Technical Reports Server (NTRS)

    Broughton, Roy M., Jr.

    2005-01-01

    The work involves two areas: Composites, optimum fiber placement with initial construction of a pressure vessel, and the general subject of insulation, a continual concern in harsh thermal environments. Insulation

  9. Evaluation of two designs for cryogenic insulation

    NASA Technical Reports Server (NTRS)

    Getty, R. C.

    1970-01-01

    Shingle-type, crinkled, aluminized polyethylene ester is thermally and structurally tested for cryogenic insulation. Insulation systems require thermal efficiency with minimum weight, and the ability to withstand vibration, acceleration, and rapid pressure drops.

  10. Inorganic glass ceramic slip rings

    NASA Technical Reports Server (NTRS)

    Glossbrenner, E. W.; Cole, S. R.

    1972-01-01

    Prototypes of slip rings have been fabricated from ceramic glass, a material which is highly resistant to deterioration due to high temperature. Slip ring assemblies were not structurally damaged by mechanical tests and performed statisfactorily for 200 hours.

  11. Topological insulators on a Mobius strip

    NASA Astrophysics Data System (ADS)

    Huang, Lang-Tao; Lee, Dung-Hai

    2011-11-01

    We study the two-dimensional Chern insulator and spin Hall insulator on a nonorientable Riemann surface, the Mobius strip, where the usual band-structure topological invariant is not defined. We show that while the flow pattern of edge currents can detect the twist of the Mobius strip in the case of Chern insulator, it can not do so for the spin Hall insulator.

  12. Topological insulators on a Mobius Strip

    NASA Astrophysics Data System (ADS)

    Huang, Lang-Tao; Lee, Dung-Hai

    2012-02-01

    We study the two dimensional Chern insulator and spin Hall insulator on a non-orientable Riemann surface, the Mobius strip, where the usual bandstructure topological invariant is not defined. We show that while the flow pattern of edge currents can detect the twist of the Mobius strip in the case of Chern insulator, it can not do so in spin Hall insulator [1]. [4pt] [1] Lang-Tao Huang and Dung-Hai Lee, Phys. Rev. B 84, 193106 (2011)

  13. Silicon-on-insulator sensors using integrated resonance-enhanced defect-mediated photodetectors.

    PubMed

    Fard, Sahba Talebi; Murray, Kyle; Caverley, Michael; Donzella, Valentina; Flueckiger, Jonas; Grist, Samantha M; Huante-Ceron, Edgar; Schmidt, Shon A; Kwok, Ezra; Jaeger, Nicolas A F; Knights, Andrew P; Chrostowski, Lukas

    2014-11-17

    A resonance-enhanced, defect-mediated, ring resonator photodetector has been implemented as a single unit biosensor on a silicon-on-insulator platform, providing a cost effective means of integrating ring resonator sensors with photodetectors for lab-on-chip applications. This method overcomes the challenge of integrating hybrid photodetectors on the chip. The demonstrated responsivity of the photodetector-sensor was 90 mA/W. Devices were characterized using refractive index modified solutions and showed sensitivities of 30 nm/RIU.

  14. Vacuum-insulated catalytic converter

    DOEpatents

    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.

  15. Nonceramic insulators for transmission lines

    SciTech Connect

    Schneider, H.M. . High Voltage Transmission Research Center); Hall, J.F. ); Karady, G. ); Rendowden, J. )

    1989-10-01

    Progress in development of nonceramic transmission lines insulator technology is reviewed. The results of a survey to utilities in the United States are presented to indicate the range of applications, distribution by voltage class, appraisal of performance, and failure modes. Concerns expressed by utility representatives at a recent workshop are described and future research and standardization needs are presented.

  16. Thermal Insulation from Hardwood Residues

    NASA Astrophysics Data System (ADS)

    Sable, I.; Grinfelds, U.; Vikele, L.; Rozenberga, L.; Zeps, M.; Luguza, S.

    2015-11-01

    Adequate heat is one of the prerequisites for human wellbeing; therefore, building insulation is required in places where the outside temperature is not suitable for living. The climate change, with its rising temperatures and longer dry periods, promotes enlargement of the regions with conditions more convenient for hardwood species than for softwood species. Birch (Betula pendula) is the most common hardwood species in Latvia. The aim of this work was to obtain birch fibres from wood residues of plywood production and to form low-density thermal insulation boards. Board formation and production was done in the presence of water; natural binder, fire retardant and fungicide were added in different concentrations. Board properties such as density, transportability or resistance to particulate loss, thermal conductivity and reaction to fire were investigated. This study included thermal insulation boards with the density of 102-120 kg/m3; a strong correlation between density and the binder amount was found. Transportability also improved with the addition of a binder, and 0.1-0.5% of the binder was the most appropriate amount for this purpose. The measured thermal conductivity was in the range of 0.040-0.043 W/(m·K). Fire resistance increased with adding the fire retardant. We concluded that birch fibres are applicable for thermal insulation board production, and it is possible to diversify board properties, changing the amount of different additives.

  17. Topological Insulators from Group Cohomology

    NASA Astrophysics Data System (ADS)

    Alexandradinata, A.; Wang, Zhijun; Bernevig, B. Andrei

    2016-04-01

    We classify insulators by generalized symmetries that combine space-time transformations with quasimomentum translations. Our group-cohomological classification generalizes the nonsymmorphic space groups, which extend point groups by real-space translations; i.e., nonsymmorphic symmetries unavoidably translate the spatial origin by a fraction of the lattice period. Here, we further extend nonsymmorphic groups by reciprocal translations, thus placing real and quasimomentum space on equal footing. We propose that group cohomology provides a symmetry-based classification of quasimomentum manifolds, which in turn determines the band topology. In this sense, cohomology underlies band topology. Our claim is exemplified by the first theory of time-reversal-invariant insulators with nonsymmorphic spatial symmetries. These insulators may be described as "piecewise topological," in the sense that subtopologies describe the different high-symmetry submanifolds of the Brillouin zone, and the various subtopologies must be pieced together to form a globally consistent topology. The subtopologies that we discover include a glide-symmetric analog of the quantum spin Hall effect, an hourglass-flow topology (exemplified by our recently proposed KHgSb material class), and quantized non-Abelian polarizations. Our cohomological classification results in an atypical bulk-boundary correspondence for our topological insulators.

  18. Effects Of Radiation On Insulators

    NASA Technical Reports Server (NTRS)

    Bouquet, Frank L.

    1988-01-01

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

  19. Advanced solid propellant motor insulation

    NASA Technical Reports Server (NTRS)

    Smith, P. L.; Russ, R. F.

    1972-01-01

    An advanced lightweight insulation system suitable for use in long duration, low pressure planetary orbiter-type motor applications was developed. Experiments included the screening of various filler and binder materials with optimization studies combining the best of each. Small scale test motor data were used to judge the degree of success.

  20. Thermal Response Of Composite Insulation

    NASA Technical Reports Server (NTRS)

    Stewart, David A.; Leiser, Daniel B.; Smith, Marnell; Kolodziej, Paul

    1988-01-01

    Engineering model gives useful predictions. Pair of reports presents theoretical and experimental analyses of thermal responses of multiple-component, lightweight, porous, ceramic insulators. Particular materials examined destined for use in Space Shuttle thermal protection system, test methods and heat-transfer theory useful to chemical, metallurgical, and ceramic engineers needing to calculate transient thermal responses of refractory composites.

  1. O-Ring-Testing Fixture

    NASA Technical Reports Server (NTRS)

    Turner, James E.; Mccluney, D. Scott

    1990-01-01

    Fixture used to evalute properties of O-rings of various materials. Hydraulic actuator positions plug in housing, creating controlled, variable gap in O-ring glands formed by grooves in plug and by inner wall of housing. Creates controlled axial and radial gaps between sealing surfaces around ring so effectiveness of material in maintaining seal determined under dynamic conditions.

  2. RINGED ACCRETION DISKS: EQUILIBRIUM CONFIGURATIONS

    SciTech Connect

    Pugliese, D.; Stuchlík, Z. E-mail: zdenek.stuchlik@physics.cz

    2015-12-15

    We investigate a model of a ringed accretion disk, made up by several rings rotating around a supermassive Kerr black hole attractor. Each toroid of the ringed disk is governed by the general relativity hydrodynamic Boyer condition of equilibrium configurations of rotating perfect fluids. Properties of the tori can then be determined by an appropriately defined effective potential reflecting the background Kerr geometry and the centrifugal effects. The ringed disks could be created in various regimes during the evolution of matter configurations around supermassive black holes. Therefore, both corotating and counterrotating rings have to be considered as being a constituent of the ringed disk. We provide constraints on the model parameters for the existence and stability of various ringed configurations and discuss occurrence of accretion onto the Kerr black hole and possible launching of jets from the ringed disk. We demonstrate that various ringed disks can be characterized by a maximum number of rings. We present also a perturbation analysis based on evolution of the oscillating components of the ringed disk. The dynamics of the unstable phases of the ringed disk evolution seems to be promising in relation to high-energy phenomena demonstrated in active galactic nuclei.

  3. DC-Powered Jumping Ring

    ERIC Educational Resources Information Center

    Jeffery, Rondo N.; Farhang, Amiri

    2016-01-01

    The classroom jumping ring demonstration is nearly always performed using alternating current (AC), in which the ring jumps or flies off the extended iron core when the switch is closed. The ring jumps higher when cooled with liquid nitrogen (LN2). We have performed experiments using DC to power the solenoid and find similarities and significant…

  4. Vortex Rings in Superfluid Helium

    NASA Astrophysics Data System (ADS)

    Alamri, Sultan Z.; Barenghi, Carlo F.

    2008-11-01

    We present results of numerical simulations of large-scale vortex rings in superfluid helium. These large-scale vortex rings consists of many discrete (quantized) vortex filaments which interact with each other moving according to the Biot-Savart law. Lifetime, structural stability and speed of large-scale vortex rings will be discussed and compared to experimental results.

  5. Uranus: the rings are black.

    PubMed

    Sinton, W M

    1977-11-01

    An upper limit of 0.05 is established for the geometric albedo of the newly discovered rings of Uranus. In view of this very low albedo, the particles of the rings cannot be ice-covered as are those of rings A and B of Saturn.

  6. 49 CFR 179.220-4 - Insulation.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 49 Transportation 3 2013-10-01 2013-10-01 false Insulation. 179.220-4 Section 179.220-4...-Pressure Tank Car Tanks (Classes DOT-111AW and 115AW) § 179.220-4 Insulation. The annular space between the inner container and the outer shell must contain an approved insulation material....

  7. 49 CFR 179.201-11 - Insulation.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 49 Transportation 3 2014-10-01 2014-10-01 false Insulation. 179.201-11 Section 179.201-11 Transportation Other Regulations Relating to Transportation (Continued) PIPELINE AND HAZARDOUS MATERIALS SAFETY...-Pressure Tank Car Tanks (Classes DOT-111AW and 115AW) § 179.201-11 Insulation. (a) Insulation shall be...

  8. 49 CFR 179.220-4 - Insulation.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 49 Transportation 3 2012-10-01 2012-10-01 false Insulation. 179.220-4 Section 179.220-4...-Pressure Tank Car Tanks (Classes DOT-111AW and 115AW) § 179.220-4 Insulation. The annular space between the inner container and the outer shell must contain an approved insulation material....

  9. 49 CFR 179.220-4 - Insulation.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 49 Transportation 3 2011-10-01 2011-10-01 false Insulation. 179.220-4 Section 179.220-4...-Pressure Tank Car Tanks (Classes DOT-111AW and 115AW) § 179.220-4 Insulation. The annular space between the inner container and the outer shell must contain an approved insulation material....

  10. 49 CFR 179.201-11 - Insulation.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 49 Transportation 3 2013-10-01 2013-10-01 false Insulation. 179.201-11 Section 179.201-11 Transportation Other Regulations Relating to Transportation (Continued) PIPELINE AND HAZARDOUS MATERIALS SAFETY...-Pressure Tank Car Tanks (Classes DOT-111AW and 115AW) § 179.201-11 Insulation. (a) Insulation shall be...

  11. 49 CFR 179.220-4 - Insulation.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 49 Transportation 2 2010-10-01 2010-10-01 false Insulation. 179.220-4 Section 179.220-4... Specifications for Non-Pressure Tank Car Tanks (Classes DOT-111AW and 115AW) § 179.220-4 Insulation. The annular space between the inner container and the outer shell must contain an approved insulation material....

  12. 49 CFR 179.220-4 - Insulation.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 49 Transportation 3 2014-10-01 2014-10-01 false Insulation. 179.220-4 Section 179.220-4...-Pressure Tank Car Tanks (Classes DOT-111AW and 115AW) § 179.220-4 Insulation. The annular space between the inner container and the outer shell must contain an approved insulation material....

  13. 49 CFR 179.201-11 - Insulation.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 49 Transportation 3 2012-10-01 2012-10-01 false Insulation. 179.201-11 Section 179.201-11 Transportation Other Regulations Relating to Transportation (Continued) PIPELINE AND HAZARDOUS MATERIALS SAFETY...-Pressure Tank Car Tanks (Classes DOT-111AW and 115AW) § 179.201-11 Insulation. (a) Insulation shall be...

  14. 49 CFR 179.201-11 - Insulation.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... Specifications for Non-Pressure Tank Car Tanks (Classes DOT-111AW and 115AW) § 179.201-11 Insulation. (a) Insulation shall be of sufficient thickness so that the thermal conductance at 60 °F. is not more than 0.075... 49 Transportation 2 2010-10-01 2010-10-01 false Insulation. 179.201-11 Section...

  15. Satellite Rings Movie

    NASA Technical Reports Server (NTRS)

    2000-01-01

    This brief movie clip (of which the release image is a still frame), taken by NASA's Cassini spacecraft as it approached Jupiter, shows the motions, over a 16 hour-period, of two satellites embedded in Jupiter's ring. The moon Adrastea is the fainter of the two, and Metis the brighter. Images such as these will be used to refine the orbits of the two bodies.

    The movie was made from images taken during a 40-hour sequence of the Jovian ring on December 11, 2000.

    Cassini is a cooperative mission of NASA, the European Space Agency and the Italian Space Agency. JPL, a division of the California Institute of Technology in Pasadena, manages Cassini for NASA's Office of Space Science, Washington, D.C.

  16. The method for detecting diffusion ring diameter in Hemagglutinin measuring

    NASA Astrophysics Data System (ADS)

    Jing, Wenbo; Liu, Xue; Duan, Jin; Wang, Xiao-man

    2014-11-01

    The diffuser ring diameter measurement is the most critical in hemagglutinin Measuring. The traditional methods, such as a vernier caliper or high-definition scanned images are subjective and low for the measurement data reliability. Propose high-resolution diffusion ring image for drop-resolution processing, adaptive Canny operator and local detection method to extract complete and clear diffusion ring boundaries, and finally make use of polynomial interpolation algorithm to make diffusion ring outer boundary pixel coordinates achieve sub-pixel accuracy and the least-squares fitting circle algorithm to calculate the precise center of the circle and the diameter of the diffuser ring. Experimental results show that the method detection time is only 63.61ms, which is a faster speed; diffuser ring diameter estimation error can achieve 0.55 pixel, high stability in experimental data. This method is adapted to the various types of influenza vaccine hemagglutinin content measurements, and has important value in the influenza vaccine quality detection.

  17. Polyimide Foams Offer Superior Insulation

    NASA Technical Reports Server (NTRS)

    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.

  18. Oligomeric ferrocene rings.

    PubMed

    Inkpen, Michael S; Scheerer, Stefan; Linseis, Michael; White, Andrew J P; Winter, Rainer F; Albrecht, Tim; Long, Nicholas J

    2016-09-01

    Cyclic oligomers comprising strongly interacting redox-active monomer units represent an unknown, yet highly desirable class of nanoscale materials. Here we describe the synthesis and properties of the first family of molecules belonging to this compound category-differently sized rings comprising only 1,1'-disubstituted ferrocene units (cyclo[n], n = 5-7, 9). Due to the close proximity and connectivity of centres (covalent Cp-Cp linkages; Cp = cyclopentadienyl) solution voltammograms exhibit well-resolved, separated 1e(-) waves. Theoretical interrogations into correlations based on ring size and charge state are facilitated using values of the equilibrium potentials of these transitions, as well as their relative spacing. As the interaction free energies between the redox centres scale linearly with overall ring charge and in conjunction with fast intramolecular electron transfer (∼10(7) s(-1)), these molecules can be considered as uniformly charged nanorings (diameter ∼1-2 nm). PMID:27554408

  19. 30 CFR 75.516-1 - Installed insulators.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 30 Mineral Resources 1 2013-07-01 2013-07-01 false Installed insulators. 75.516-1 Section 75.516-1 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR COAL MINE SAFETY AND HEALTH... insulators. Well-insulated insulators is interpreted to mean well-installed insulators. Insulated J-hooks...

  20. 30 CFR 75.516-1 - Installed insulators.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 30 Mineral Resources 1 2014-07-01 2014-07-01 false Installed insulators. 75.516-1 Section 75.516-1 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR COAL MINE SAFETY AND HEALTH... insulators. Well-insulated insulators is interpreted to mean well-installed insulators. Insulated J-hooks...

  1. 30 CFR 75.516-1 - Installed insulators.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 30 Mineral Resources 1 2012-07-01 2012-07-01 false Installed insulators. 75.516-1 Section 75.516-1 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR COAL MINE SAFETY AND HEALTH... insulators. Well-insulated insulators is interpreted to mean well-installed insulators. Insulated J-hooks...

  2. 30 CFR 75.516-1 - Installed insulators.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 30 Mineral Resources 1 2011-07-01 2011-07-01 false Installed insulators. 75.516-1 Section 75.516-1 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR COAL MINE SAFETY AND HEALTH... insulators. Well-insulated insulators is interpreted to mean well-installed insulators. Insulated J-hooks...

  3. 30 CFR 75.516-1 - Installed insulators.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Installed insulators. 75.516-1 Section 75.516-1 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR COAL MINE SAFETY AND HEALTH... insulators. Well-insulated insulators is interpreted to mean well-installed insulators. Insulated J-hooks...

  4. Reflective insulating blinds for windows and the like

    DOEpatents

    Barnes, Paul R.; Shapira, Hanna B.

    1981-01-01

    Energy-conserving window blinds are provided. The blinds are fabricated from coupled and adjustable slats, each slat having an insulation layer and a reflective surface to face outwardly when the blinds are closed. A range of desired light and air transmission may be selected with the reflective surfaces of the slats adapted to direct sunlight upward toward the ceiling when the blinds are open. When the blinds are closed, the insulation of the slats reduces the heat loss or gain produced by the windows. If desired, the reflective surfaces of the slats may be concave. The edges of the slats are designed to seal against adjacent slats when the blinds are closed to ensure minimum air flow between slats.

  5. Reflective insulating blinds for windows and the like

    DOEpatents

    Barnes, P.R.; Shapira, H.B.

    1979-12-07

    Energy-conserving window blinds are provided. The blinds are fabricated from coupled and adjustable slats, each slat having an insulation layer and a reflective surface to face outwardly when the blinds are closed. A range of desired light and air transmission may be selected with the reflective surfaces of the slats adapted to direct sunlight upward toward the ceiling when the blinds are open. When the blinds are closed, the insulation of the slats reduces the heat loss or gain produced by the windows. If desired, the reflective surfaces of the slats may be concave. The edges of the slats are designed to seal against adjacent slats when the blinds are closed to ensure minimum air flow between slats.

  6. Uranus rings and two moons

    NASA Technical Reports Server (NTRS)

    1986-01-01

    Voyager 2 has discovered two 'shepherd' satellites associated with the rings of Uranus. The two moons -- designated 1986U7 and 1986U8 -- are seen here on either side of the bright epsilon ring; all nine of the known Uranian rings are visible. The image was taken Jan. 21, 1986, at a distance of 4.1 million kilometers (2.5 million miles) and resolution of about 36 km (22 mi). The image was processed to enhance narrow features. The epsilon ring appears surrounded by a dark halo as a result of this processing; occasional blips seen on the ring are also artifacts. Lying inward from the epsilon ring are the delta, gamma and eta rings; then the beta and alpha rings; and finally the barely visible 4, 5 and 6 rings. The rings have been studied since their discovery in 1977, through observations of how they diminish the light of stars they pass in front of. This image is the first direct observation of all nine rings in reflected sunlight. They range in width from about 100 km (60 mi) at the widest part of the epsilon ring to only a few kilometers for most of the others. The discovery of the two ring moons 1986U7 and 1986U8 is a major advance in our understanding of the structure of the Uranian rings and is in good agreement with theoretical predictions of how these narrow rings are kept from spreading out. Based on likely surface brightness properties, the moons are of roughly 2O- and 3O-km diameter, respectively. The Voyager project is managed for NASA by the Jet Propulsion Laboratory.

  7. Thermal Testing and Analysis of an Efficient High-Temperature Multi-Screen Internal Insulation

    NASA Technical Reports Server (NTRS)

    Weiland, Stefan; Handrick, Karin; Daryabeigi, Kamran

    2007-01-01

    Conventional multi-layer insulations exhibit excellent insulation performance but they are limited to the temperature range to which their components reflective foils and spacer materials are compatible. For high temperature applications, the internal multi-screen insulation IMI has been developed that utilizes unique ceramic material technology to produce reflective screens with high temperature stability. For analytical insulation sizing a parametric material model is developed that includes the main contributors for heat flow which are radiation and conduction. The adaptation of model-parameters based on effective steady-state thermal conductivity measurements performed at NASA Langley Research Center (LaRC) allows for extrapolation to arbitrary stack configurations and temperature ranges beyond the ones that were covered in the conductivity measurements. Experimental validation of the parametric material model was performed during the thermal qualification test of the X-38 Chin-panel, where test results and predictions showed a good agreement.

  8. Ideals of generalized matrix rings

    SciTech Connect

    Budanov, Aleksandr V

    2011-01-31

    Let R and S be rings, and {sub R}M{sub S} and {sub S}N{sub R} bimodules. In the paper, in terms of isomorphisms of lattices, relationships between the lattices of one-sided and two-sided ideals of the generalized matrix ring and the corresponding lattices of ideals of the rings R and S are described. Necessary and sufficient conditions for a pair of ideals I, J of rings R and S, respectively, to be the main diagonal of some ideal of the ring K are also obtained. Bibliography: 8 titles.

  9. O-Ring-Testing Fixture

    NASA Technical Reports Server (NTRS)

    Turner, James E.; Mccluney, D. Scott

    1991-01-01

    Fixture tests O-rings for sealing ability under dynamic conditions after extended periods of compression. Hydraulic cylinder moves plug in housing. Taper of 15 degrees on plug and cavity of housing ensures that gap created between O-ring under test and wall of cavity. Secondary O-rings above and below test ring maintain pressure applied to test ring. Evaluates effects of variety of parameters, including temperature, pressure, rate of pressurization, rate and magnitude of radial gap movement, and pretest compression time.

  10. New instability of Saturn's ring

    SciTech Connect

    Goertz, C.K.; Morfill, G.

    1988-05-01

    Perturbations in the Saturn ring's mass density are noted to be prone to instabilities through the sporadic elevation of submicron-size dust particles above the rings, which furnishes an effective angular momentum exchange between the rings and Saturn. The dust thus elevated from the ring settles back onto it at a different radial distance. The range of wavelength instability is determinable in light of the dust charge, the average radial displacement of the dust, and the fluctuation of these quantities. It is suggested that at least some of the B-ring's ringlets may arise from the instability.

  11. High-quality-factor photonic crystal ring resonator.

    PubMed

    Zhang, Yong; Zeng, Cheng; Li, Danping; Gao, Ge; Huang, Zengzhi; Yu, Jinzhong; Xia, Jinsong

    2014-03-01

    A design for enhancing the quality (Q) factor of a photonic crystal ring resonator (PCRR) is introduced. The highest Q factor based on simulations is 121,000. The analysis of momentum space distributions of the electric field profile for PCRR resonance shows that a high Q factor of a PCRR is attributed to the reduction of tangential k-vector component inside the leaky region. A high Q factor of 75,200 is experimentally demonstrated for a modified PCRR on a silicon-on-insulator wafer. The high-Q-factor PCRR demonstrated here will be beneficial for channel drop filters, lasers, sensors, and other applications. PMID:24690727

  12. Cut bullwork in hv-insulator installation

    SciTech Connect

    Not Available

    1980-01-01

    With an insulation and strength capability as good as or better than porcelain-at one-tenth the weight-insulators made of an assembly of copolymer weathersheds on an epoxy-fiberglass center rod are proving to be an effective option in high-voltage line construction. Experience has shown that the high-strength-to-weight, factory-assembled insulators can cut line-construction costs. These Hi-Lite insulators, are also helping to meet many line design and upgrading requirements that might be difficult or prohibitively expensive using traditional insulation systems.

  13. Converting normal insulators into topological insulators via tuning orbital levels

    NASA Astrophysics Data System (ADS)

    Shi, Wu-Jun; Liu, Junwei; Xu, Yong; Xiong, Shi-Jie; Wu, Jian; Duan, Wenhui

    2015-11-01

    Tuning the spin-orbit coupling strength via foreign element doping and modifying bonding strength via strain engineering are the major routes to convert normal insulators to topological insulators. We here propose an alternative strategy to realize topological phase transition by tuning the orbital level. Following this strategy, our first-principles calculations demonstrate that a topological phase transition in the cubic perovskite-type compounds CsGeBr3 and CsSnBr3 could be facilitated by carbon substitutional doping. Such a unique topological phase transition predominantly results from the lower orbital energy of the carbon dopant, which can pull down the conduction bands and even induce band inversion. Beyond conventional approaches, our finding of tuning the orbital level may greatly expand the range of topologically nontrivial materials.

  14. A season in Saturn's rings: Cycling, recycling and ring history

    NASA Astrophysics Data System (ADS)

    Esposito, L. W.; Meinke, B. K.; Albers, N.; Sremcevic, M.

    2012-04-01

    Cassini experiments have watched Saturn's ring system evolve before our eyes. Images and occultations show changes and transient events. The rings are a dynamic and complex geophysical system, incompletely modeled as a single-phase fluid. Key Cassini observations: High resolution images show straw, propellers, embedded moonlets, and F ring objects. Multiple UVIS, RSS and VIMS occutlations indicate multimodal ringlet and edge structure, including free and forced modes along with stochastic perturbations that are most likely caused by nearby mass concentrations. Vertical excursions are evident at ring edges and in other perturbed regions. The rings are occasionally hit by meteorites that leave a signature that may last centuries; meteoritic dust pollutes the rings. Temperature, reflectance and transmission spectra are influenced by the dynamical state of the ring particles. Saturn's Equinox 2009: Oblique lighting exposed vertical structure and embedded objects. The rings were the coldest ever. Images inspired new occultation and spectral analysis that show abundant structure in the perturbed regions. The rings are more variable and complex than we had expected prior to this seasonal viewing geometry. Sub-kilometer structure in power spectral analysis: Wavelet analysis shows features in the strongest density waves and at the shepherded outer edge of the B ring. Edges are variable as shown by multiple occultations and occultations of double stars. F ring kittens: 25 features seen in the first 102 occultations show a weak correlation with Prometheus location. We interpret these features as temporary aggregations. Simulation results indicate that accretion must be enhanced to match the kittens' size distribution. Images show that Prometheus triggers the formation of transient objects. Propellers and ghosts: Occulations and images provide evidence for small moonlets in the A, B and C rings. These indicate accretion occurs inside the classical Roche limit. Implications

  15. A ceramic radial insulation structure for a relativistic electron beam vacuum diode.

    PubMed

    Xun, Tao; Yang, Hanwu; Zhang, Jiande; Liu, Zhenxiang; Wang, Yong; Zhao, Yansong

    2008-06-01

    For one kind of a high current diode composed of a small disk-type alumina ceramic insulator water/vacuum interface, the insulation structure was designed and experimentally investigated. According to the theories of vacuum flashover and the rules for radial insulators, a "cone-column" anode outline and the cathode shielding rings were adopted. The electrostatic field along the insulator surface was obtained by finite element analysis simulating. By adjusting the outline of the anode and reshaping the shielding rings, the electric fields were well distributed and the field around the cathode triple junction was effectively controlled. Area weighted statistical method was applied to estimate the surface breakdown field. In addition, the operating process of an accelerator based on a spiral pulse forming line (PFL) was simulated through the PSPICE software to get the waveform of charging and diode voltage. The high voltage test was carried out on a water dielectric spiral PFL accelerator with long pulse duration, and results show that the diode can work stably in 420 kV, 200 ns conditions. The experimental results agree with the theoretical and simulated results.

  16. Music, Myth, and Education: The Case of "The Lord of the Rings" Film Trilogy

    ERIC Educational Resources Information Center

    Jorgensen, Estelle R.

    2010-01-01

    In probing the interrelationship of myth, meaning, and education, the author offers a case in point, notably, Peter Jackson's film adaptations and Howard Shore's musical scores for J. R. R. Tolkien's "The Lord of the Rings trilogy"--"The Fellowship of the Ring," "The Two Towers," and "The Return of the King." Intersecting literature, film, and…

  17. Chromatin insulators: lessons from the fly.

    PubMed

    Gurudatta, B V; Corces, Victor G

    2009-07-01

    Chromatin insulators are DNA-protein complexes with broad functions in nuclear biology. Drosophila has at least five different types of insulators; recent results suggest that these different insulators share some components that may allow them to function through common mechanisms. Data from genome-wide localization studies of insulator proteins indicate a possible functional specialization, with different insulators playing distinct roles in nuclear biology. Cells have developed mechanisms to control insulator activity by recruiting specialized proteins or by covalent modification of core components. Current results suggest that insulators set up cell-specific blueprints of nuclear organization that may contribute to the establishment of different patterns of gene expression during cell differentiation and development.

  18. Organic topological insulators in organometallic lattices.

    PubMed

    Wang, Z F; Liu, Zheng; Liu, Feng

    2013-01-01

    Topological insulators are a recently discovered class of materials having insulating bulk electronic states but conducting boundary states distinguished by nontrivial topology. So far, several generations of topological insulators have been theoretically predicted and experimentally confirmed, all based on inorganic materials. Here, based on first-principles calculations, we predict a family of two-dimensional organic topological insulators made of organometallic lattices. Designed by assembling molecular building blocks of triphenyl-metal compounds with strong spin-orbit coupling into a hexagonal lattice, this new classes of organic topological insulators are shown to exhibit nontrivial topological edge states that are robust against significant lattice strain. We envision that organic topological insulators will greatly broaden the scientific and technological impact of topological insulators.

  19. Approximating metal-insulator transitions

    NASA Astrophysics Data System (ADS)

    Danieli, Carlo; Rayanov, Kristian; Pavlov, Boris; Martin, Gaven; Flach, Sergej

    2015-12-01

    We consider quantum wave propagation in one-dimensional quasiperiodic lattices. We propose an iterative construction of quasiperiodic potentials from sequences of potentials with increasing spatial period. At each finite iteration step, the eigenstates reflect the properties of the limiting quasiperiodic potential properties up to a controlled maximum system size. We then observe approximate Metal-Insulator Transitions (MIT) at the finite iteration steps. We also report evidence on mobility edges, which are at variance to the celebrated Aubry-André model. The dynamics near the MIT shows a critical slowing down of the ballistic group velocity in the metallic phase, similar to the divergence of the localization length in the insulating phase.

  20. High temperature structural insulating material

    DOEpatents

    Chen, W.Y.

    1984-07-27

    A high temperature structural insulating material useful as a liner for cylinders of high temperature engines through the favorable combination of high service temperature (above about 800/sup 0/C), low thermal conductivity (below about 0.2 W/m/sup 0/C), and high compressive strength (above about 250 psi). The insulating material is produced by selecting hollow ceramic beads with a softening temperature above about 800/sup 0/C, a diameter within the range of 20-200 ..mu..m, and a wall thickness in the range of about 2 to 4 ..mu..m; compacting the beads and a compatible silicate binder composition under pressure and sintering conditions to provide the desired structural form with the structure having a closed-cell, compact array of bonded beads.

  1. High temperature structural insulating material

    DOEpatents

    Chen, Wayne Y.

    1987-01-01

    A high temperature structural insulating material useful as a liner for cylinders of high temperature engines through the favorable combination of high service temperature (above about 800.degree. C.), low thermal conductivity (below about 0.2 W/m.degree. C.), and high compressive strength (above about 250 psi). The insulating material is produced by selecting hollow ceramic beads with a softening temperature above about 800.degree. C., a diameter within the range of 20-200 .mu.m, and a wall thickness in the range of about 2-4 .mu.m; compacting the beads and a compatible silicate binder composition under pressure and sintering conditions to provide the desired structural form with the structure having a closed-cell, compact array of bonded beads.

  2. High temperature structural insulating material

    DOEpatents

    Chen, Wayne Y.

    1987-01-06

    A high temperature structural insulating material useful as a liner for cylinders of high temperature engines through the favorable combination of high service temperature (above about 800.degree. C.), low thermal conductivity (below about 0.2 W/m.degree. C.), and high compressive strength (above about 250 psi). The insulating material is produced by selecting hollow ceramic beads with a softening temperature above about 800.degree. C., a diameter within the range of 20-200 .mu.m, and a wall thickness in the range of about 2-4 .mu.m; compacting the beads and a compatible silicate binder composition under pressure and sintering conditions to provide the desired structural form with the structure having a closed-cell, compact array of bonded beads.

  3. Insulation assembly for electric machine

    DOEpatents

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

    2013-10-15

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

  4. Insulation for a Thermionic Microbattery

    SciTech Connect

    James P. Blanchard

    2004-09-19

    Microelectronmechanical Systems (MEMS) have not gained wide use because they lack the on-device power required by many important applications. To supply this need power, on can consider power from fossil fuels, but nuclear sources provide an intriguing option in terms of power density and lifetime. In order to make use of alpha particles, one is forced to use thermal approaches because diodes are damaged by the high energy of the alpha particles, one is forced to use thermal approaches because diodes are damaged by the high energy of the alphas. One difficulty, though, is that the surface to volume ration increases as we move to smaller scales and heat losses thus become significant at MEMS scales. Hence, efficient microscale insulation is needed to permit high overall efficiencies. This research explores concepts for one variety of microscale insulation created using MEMS fabrication techniques.

  5. SUPPORTING AND HEAT INSULATING MEANS

    DOEpatents

    Birmingham, B.W.; Brown, H.; Scott, R.B.; Vander-arend, P.C.

    1959-01-27

    A method is described for simultaneously supporting inner and outer members spaced from each other and heat insulating them from each other comprising an inner and outer member together defining an annular cavity. Each member carries a shoulder projecting towards the other member. A stack of annular metal plates in the cavity is held between the shoulder of the outer member and the shoulder of the inner member. The edges of the metal plate forming the stack are exposed to the cavity and to evacuation conditions which may exist within thc cavity. The stack of metal plates acts to both support one of the members with respect to the other and as a heat insulator.

  6. Magnetically insulated transmission line oscillator

    DOEpatents

    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.

  7. Magnetically insulated transmission line oscillator

    DOEpatents

    Bacon, Larry D.; Ballard, William P.; Clark, M. Collins; Marder, Barry M.

    1988-01-01

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

  8. Continuous ring furnaces

    SciTech Connect

    De Stefani, G.; Genevois, J.L.; Paolo, P.

    1981-01-06

    A smoke conducting apparatus for use particularly with continuous ring furnaces (e.g., Hoffman furnaces) wherein each furnace chamber is connected to the smoke channel, the latter being a metal pipe inclined slightly from horizontal and provided with one or more traps along the length of its bottom surface, each trap containing a removable receptacle, and heating means being disposed along the bottom of the channel to fluidize tarry deposits of combustion products so that such deposits will flow by gravity into the removable receptacle.

  9. Lightweight ceramic insulation and method

    NASA Technical Reports Server (NTRS)

    Green, David J. (Inventor)

    1990-01-01

    A process is disclosed for manufacturing a low density ceramic powder which can be formed to make a lightweight material for insulation or other construction. The ceramic product made from the process has a final density of less than 25 to about 1 percent of the theoretical weight of the ceramic powder. The ceramic product is lightweight and can be made to withstand high temperatures greater than 1400 C.

  10. Materials for foam type insulation

    NASA Technical Reports Server (NTRS)

    Hill, W. E.

    1971-01-01

    An internal foam fabrication is one of the concepts being considered for cryogenic insulation on the hydrogen tanks of the shuttle vehicle. The three-dimensional polyurethane used on the S-4 B tanks failed to meet the higher temperature requirements of the shuttle vehicle, however, and other foams under consideration include polyisocyanurates, polyphenylene oxides, polyimides, and polybenzimidazoles. Improved adhesive systems for attaching the foams to the interior tank wall are under study.

  11. Flexible pile thermal barrier insulator

    NASA Technical Reports Server (NTRS)

    Anderson, G. E.; Fell, D. M.; Tesinsky, J. S. (Inventor)

    1978-01-01

    A flexible pile thermal barrier insulator included a plurality of upstanding pile yarns. A generally planar backing section supported the upstanding pile yarns. The backing section included a plurality of filler yarns forming a mesh in a first direction. A plurality of warp yarns were looped around said filler yarns and pile yarns in the backing section and formed a mesh in a second direction. A binder prevented separation of the yarns in the backing section.

  12. Saturn ring temperature variations with approaching ring equinox

    NASA Astrophysics Data System (ADS)

    Spilker, L.; Leyrat, C.; Flandes, A.; Altobelli, N.; Pilorz, S.; Ferrari, C.; Edgington, S.

    2009-04-01

    Cassini's Composite Infrared Spectrometer (CIRS) has acquired a wide-ranging set of thermal measurements of Saturn's main rings (A, B, C and Cassini Division) at solar elevations ranging from less than one degree to 24 degrees. At Saturn equinox in August the solar elevation angle will reach zero as the sun traverses from the south to north side of the rings. For the data acquired to date, temperatures were retrieved for the lit and unlit rings over a variety of ring geometries that include solar elevation, as well as spacecraft elevation, phase angle and local hour angle. To first order, the largest temperature changes on the lit face of the rings are driven by variations in phase angle while differences in temperature with changing spacecraft elevation and local time are a secondary effect. Decreasing ring temperature with decreasing solar elevation are observed for both the lit and unlit faces of the rings after phase angle and local time effects are taken into account. As the solar elevation continues to decrease, the ring temperatures are decreasing in a non-linear fashion. The difference in temperature between the lit and unlit sides of the rings is decreasing also with decreasing solar elevation. Using ring thermal models developed by Leyrat we extrapolate to the expected minimum ring temperatures at equinox for our planned CIRS ring observations. This research was carried out at the Jet Propulsion Laboratory, California Institute of Technology, under contract with NASA and at CEA Saclay supported by the "Programme National de Planetologie". Copyright 2009 California Institute of Technology. Government sponsorship acknowledged.

  13. Improved Aerogel Vacuum Thermal Insulation

    NASA Technical Reports Server (NTRS)

    Ruemmele, Warren P.; Bue, Grant C.

    2009-01-01

    An improved design concept for aerogel vacuum thermal-insulation panels calls for multiple layers of aerogel sandwiched between layers of aluminized Mylar (or equivalent) poly(ethylene terephthalate), as depicted in the figure. This concept is applicable to both the rigid (brick) form and the flexible (blanket) form of aerogel vacuum thermal-insulation panels. Heretofore, the fabrication of a typical aerogel vacuum insulating panel has involved encapsulation of a single layer of aerogel in poly(ethylene terephthalate) and pumping of gases out of the aerogel-filled volume. A multilayer panel according to the improved design concept is fabricated in basically the same way: Multiple alternating layers of aerogel and aluminized poly(ethylene terephthalate) are assembled, then encapsulated in an outer layer of poly(ethylene terephthalate), and then the volume containing the multilayer structure is evacuated as in the single-layer case. The multilayer concept makes it possible to reduce effective thermal conductivity of a panel below that of a comparable single-layer panel, without adding weight or incurring other performance penalties. Implementation of the multilayer concept is simple and relatively inexpensive, involving only a few additional fabrication steps to assemble the multiple layers prior to evacuation. For a panel of the blanket type, the multilayer concept, affords the additional advantage of reduced stiffness.

  14. Weak antilocalisation in topological insulators

    NASA Astrophysics Data System (ADS)

    Bi, Xintao; Hankiewicz, Ewelina; Culcer, Dimitrie

    2014-03-01

    Topological insulators (TI) have changed our understanding of insulating behaviour. They are insulators in the bulk but conducting along their surfaces due to spin-orbit interaction. Much of the recent research focuses on overcoming the transport bottleneck, the fact that surface state transport is overwhelmed by bulk transport stemming from unintentional doping. The key to overcoming this bottleneck is identifying unambiguous signatures of surface state transport. This talk will discuss one such signature, which is manifest in the coherent backscattering of electrons. Due to strong spin-orbit coupling in TI one expects to observe weak antilocalisation rather than weak localisation, meaning that coherent backscattering increases the electrical conductivity. The features of this effect, however, are rather subtle, because in TI the impurities have strong spin-orbit coupling as well. I will show that spin-orbit coupled impurities introduce an additional time scale, which is expected to be shorter than the dephasing time, and the resulting conductivity has a logarithmic dependence on the carrier density, a behaviour hitherto unknown in 2D electron systems. The result we predict is observable experimentally and would provide a smoking gun test of surface transport.

  15. Topological Insulators at Room Temperature

    SciTech Connect

    Zhang, Haijun; Liu, Chao-Xing; Qi, Xiao-Liang; Dai, Xi; Fang, Zhong; Zhang, Shou-Cheng; /Stanford U., Phys. Dept.

    2010-03-25

    Topological insulators are new states of quantum matter with surface states protected by the time-reversal symmetry. In this work, we perform first-principle electronic structure calculations for Sb{sub 2}Te{sub 3}, Sb{sub 2}Se{sub 3}, Bi{sub 2}Te{sub 3} and Bi{sub 2}Se{sub 3} crystals. Our calculations predict that Sb{sub 2}Te{sub 3}, Bi{sub 2}T e{sub 3} and Bi{sub 2}Se{sub 3} are topological insulators, while Sb{sub 2}Se{sub 3} is not. In particular, Bi{sub 2}Se{sub 3} has a topologically non-trivial energy gap of 0.3eV , suitable for room temperature applications. We present a simple and unified continuum model which captures the salient topological features of this class of materials. These topological insulators have robust surface states consisting of a single Dirac cone at the {Lambda} point.

  16. Keck observations of the 2002 2003 jovian ring plane crossing

    NASA Astrophysics Data System (ADS)

    de Pater, Imke; Showalter, Mark R.; Macintosh, Bruce

    2008-05-01

    We present new observations of Jupiter's ring system at a wavelength of 2.2 μm obtained with the 10-m W.M. Keck telescopes on three nights during a ring plane crossing: UT 19 December 2002, and 22 and 26 January 2003. We used conventional imaging, plus adaptive optics on the last night. Here we present detailed radial profiles of the main ring, halo and gossamer rings, and interpret the data together with information extracted from radio observations of Jupiter's synchrotron radiation. The main ring is confined to a 800-km-wide annulus between 128,200 and 129,000 km, with a ˜5000 km extension on the inside. The normal optical depth is 8×10, 15% of which is provided by bodies with radii a≳5 cm. These bodies are as red as Metis. Half the optical depth, τ≈4×10, is attributed to micron-sized dust, and the remaining τ≈3×10 to grains tens to hundreds of μm in size. The inward extension consists of micron-sized ( a≲10 μm) dust, which probably migrates inward under Poynting-Robertson drag. The inner limit of this extension falls near the 3:2 Lorentz resonance (at orbital radius r=122,400 km), and coincides with the outer limit of the halo. The gossamer rings appear to be radially confined, rather than broad sheets of material. The Amalthea ring is triangularly shaped, with a steep outer dropoff over ˜5000 km, extending a few 1000 km beyond the orbit of Amalthea, and a more gradual inner dropoff over 15,000-20,000 km. The inner edge is near the location of the synchronous orbit. The optical depth in the Amalthea ring is ˜5×10, up to 20% of which is comprised of macroscopic material. The optical depth in the Thebe ring is a factor of 3 smaller.

  17. Intraocular Radio-Opaque Ring.

    PubMed

    Shieh, Christine; Folz, Emily; Fekrat, Sharon

    2015-01-01

    A radiologist noted a radio-opaque object in the eye of a woman undergoing X-ray examination to determine the safety of magnetic resonance imaging (MRI). Water's X-ray shows the titanium locking c-ring of a type 1 Boston keratoprosthesis. This ring was added in 2004 to prevent intraocular disassembly of the device. The nonmagnetic ring does not prevent MRI imaging. The titanium locking c-ring and the titanium or polymethyl methacrylate back plate of the Boston keratoprosthesis are safe for MRI imaging. PMID:26271082

  18. Saturn's Rings Edge-on

    NASA Technical Reports Server (NTRS)

    1995-01-01

    In one of nature's most dramatic examples of 'now-you see-them, now-you-don't', NASA's Hubble Space Telescope captured Saturn on May 22, 1995 as the planet's magnificent ring system turned edge-on. This ring-plane crossing occurs approximately every 15 years when the Earth passes through Saturn's ring plane.

    For comparison, the top picture was taken by Hubble on December 1, 1994 and shows the rings in a more familiar configuration for Earth observers.

    The bottom picture was taken shortly before the ring plane crossing. The rings do not disappear completely because the edge of the rings reflects sunlight. The dark band across the middle of Saturn is the shadow of the rings cast on the planet (the Sun is almost 3 degrees above the ring plane.) The bright stripe directly above the ring shadow is caused by sunlight reflected off the rings onto Saturn's atmosphere. Two of Saturn's icy moons are visible as tiny starlike objects in or near the ring plane. They are, from left to right, Tethys (slightly above the ring plane) and Dione.

    This observation will be used to determine the time of ring-plane crossing and the thickness of the main rings and to search for as yet undiscovered satellites. Knowledge of the exact time of ring-plane crossing will lead to an improved determination of the rate at which Saturn 'wobbles' about its axis (polar precession).

    Both pictures were taken with Hubble's Wide Field Planetary Camera 2. The top image was taken in visible light. Saturn's disk appears different in the bottom image because a narrowband filter (which only lets through light that is not absorbed by methane gas in Saturn's atmosphere) was used to reduce the bright glare of the planet. Though Saturn is approximately 900 million miles away, Hubble can see details as small as 450 miles across.

    The Wide Field/Planetary Camera 2 was developed by the Jet Propulsion Laboratory and managed by the Goddard Spaced Flight Center for NASA's Office of Space Science

  19. Split ring containment attachment device

    DOEpatents

    Sammel, Alfred G.

    1996-01-01

    A containment attachment device 10 for operatively connecting a glovebag 200 to plastic sheeting 100 covering hazardous material. The device 10 includes an inner split ring member 20 connected on one end 22 to a middle ring member 30 wherein the free end 21 of the split ring member 20 is inserted through a slit 101 in the plastic sheeting 100 to captively engage a generally circular portion of the plastic sheeting 100. A collar potion 41 having an outer ring portion 42 is provided with fastening means 51 for securing the device 10 together wherein the glovebag 200 is operatively connected to the collar portion 41.

  20. Statistical ring current of Saturn

    NASA Astrophysics Data System (ADS)

    Carbary, J. F.; Achilleos, N.; Arridge, C. S.

    2012-06-01

    The statistical ring current of Saturn has been determined from the curl of the median magnetic field derived from over 5 years of observations of the Cassini magnetometer. The main issue addressed here is the calculation of the statistical ring current of Saturn by directly computing, for the first time, the symmetrical part of the ring current J from the Maxwell equation ∇ × B = μ0J from assembling the perturbation magnetic field B from 2004 through 2010. This study validates previous studies, based on fewer data and not using ∇ × B, and shows that the ring current flows eastward (in the +ϕ or corotation direction) and extends from ˜3 RS to at least ˜20 RS (1 RS = 60,268 km), which is the vicinity of the dayside magnetopause; that the ring current has a peak strength of ˜75 pA/m2 at ˜9.5 RS; and that the ring current has a half-width of ˜1.5 RS. Two outcomes of this study are that the ring current bends northward, as suggested by the “bowl” model of Saturn's plasma sheet, and that the total ring current is 9.2 ± 1.0 MA. In the context of future endeavors, the statistical ring current presented here can be used for calculations of the magnetic field of Saturn for particle drifts, field line mapping, and J × B force.

  1. Formation of lunar basin rings

    USGS Publications Warehouse

    Hodges, C.A.; Wilhelms, D.E.

    1978-01-01

    The origin of the multiple concentric rings that characterize lunar impact basins, and the probable depth and diameter of the transient crater have been widely debated. As an alternative to prevailing "megaterrace" hypotheses, we propose that the outer scarps or mountain rings that delineate the topographic rims of basins-the Cordilleran at Orientale, the Apennine at Imbrium, and the Altai at Nectaris-define the transient cavities, enlarged relatively little by slumping, and thus are analogous to the rim crests of craters like Copernicus; inner rings are uplifted rims of craters nested within the transient cavity. The magnitude of slumping that occurs on all scarps is insufficient to produce major inner rings from the outer. These conclusions are based largely on the observed gradational sequence in lunar central uplifts:. from simple peaks through somewhat annular clusters of peaks, peak and ring combinations and double ring basins, culminating in multiring structures that may also include peaks. In contrast, belts of slump terraces are not gradational with inner rings. Terrestrial analogs suggest two possible mechanisms for producing rings. In some cases, peaks may expand into rings as material is ejected from their cores, as apparently occurred at Gosses Bluff, Australia. A second process, differential excavation of lithologically diverse layers, has produced nested experimental craters and is, we suspect, instrumental in the formation of terrestrial ringed impact craters. Peak expansion could produce double-ring structures in homogeneous materials, but differential excavation is probably required to produce multiring and peak-in-ring configurations in large lunar impact structures. Our interpretation of the representative lunar multiring basin Orientale is consistent with formation of three rings in three layers detected seismically in part of the Moon-the Cordillera (basin-bounding) ring in the upper crust, the composite Montes Rook ring in the underlying

  2. Silicon-on-insulator integrated optic transceivers

    NASA Astrophysics Data System (ADS)

    Morris, Robin J.

    1997-04-01

    Silicon-on-insulator offers the chance to produce integrated optical `circuits' with properties which are appropriate even for demanding applications. Developments in SOI waveguide technology have been combined with the well- developed micro-engineering properties of silicon for use in fields such as telecommunication and sensors. An integrated optical transceiver is selected as an example with which to describe the features of the technology. The design will be used to illustrate the benefits brought by the use of SOI waveguide elements. These functional `building blocks' include alignment features, integrated mode-matching waveguide tapers, tap-off couplers and low back-reflection interfaces. Further possible integrated elements are described, including WDMs, as relevant to optical transceiver technology. The economic and technical drivers and difficulties surrounding the convergence of electrical, CMOS-like and optical SOI technologies are also considered. There is a spreading acceptance that low-cost motherboard technology is needed, to realize volume production of optical transceivers. A range of materials solutions have been reported. The relative merits of SOI technology are discussed. Motherboard techniques provide a platform for precise optical alignment between components. The SOI approach can deliver self-aligned waveguide and hybridization features--such as fiber attach or laser diode connections--and includes the ability to adapt to laser diode and optical fiber near-field characteristics.

  3. Transport studies of mesoscopic and magnetic topological insulators

    NASA Astrophysics Data System (ADS)

    Kandala, Abhinav

    Topological Insulators (TI) are a novel class of materials that are ideally insulating in the bulk, but have gapless, metallic states at the surface. These surface states have very exciting properties such as suppressed backscattering and spin-momentum locking, which are of great interest for research efforts towards dissipation-less electronics and spintronics. The popular thermo-electrics from the Bi chalcogenide family -- Bi2Se3 and Bi 2Te3 -- have been experimentally demonstrated to be promising candidate TI materials, and form the chosen material system for this dissertation research. The first part of this dissertation research focuses on low temperature magneto-transport measurements of mesoscopic topological insulator devices (Chapter 3). The top-down patterning of epitaxial thin films of Bi2Se 3 and Bi2Te3 (that are plagued with bulk conduction) is motivated, in part, by an effort to enhance the surface-to-volume ratio in mesoscopic channels. At cryogenic temperatures, transport measurements of these devices reveal periodic conductance fluctuations in straight channel devices, despite the lack of any explicit patterning of the TI film into a ring or a loop. A careful analysis of the surface morphology and comparison with the transport data then demonstrate that scattering off the edges of triangular plateaus at the surface leads to the creation of Aharonov-Bohm electronic orbits responsible for the periodicity. Another major focus of this dissertation work is on combining topological insulators with magnetism. This has been shown to open a gap in the surface states leading to possibilities of magnetic "gating" and the realization of dissipation-less transport at zero-field, amongst several other exotic quantum phenomena. In this dissertation, I present two different schemes for probing these effects in electrical transport devices -- interfacing with insulating ferromagnets (Chapter 4) and bulk magnetic doping (Chapter 5). In Chapter 4, I shall present the

  4. Insulation Progress since the Mid-1950s

    NASA Astrophysics Data System (ADS)

    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.

  5. ASRM case insulation design and development

    NASA Technical Reports Server (NTRS)

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

    1992-01-01

    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.

  6. High pressure electrical insulated feed thru connector

    DOEpatents

    Oeschger, Joseph E.; Berkeland, James E.

    1979-11-13

    A feed-thru type hermetic electrical connector including at least one connector pin feeding through an insulator block within the metallic body of the connector shell. A compression stop arrangement coaxially disposed about the insulator body is brazed to the shell, and the shoulder on the insulator block bears against this top in a compression mode, the high pressure or internal connector being at the opposite end of the shell. Seals between the pin and an internal bore at the high pressure end of the insulator block and between the insulator block and the metallic shell at the high pressure end are hermetically brazed in place, the first of these also functioning to transfer the axial compressive load without permitting appreciable shear action between the pin and insulator block.

  7. Hydrogen storage in insulated pressure vessels

    SciTech Connect

    Aceves, S.M.; Garcia-Villazana, O.

    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.

  8. Foam insulated transfer line test report

    SciTech Connect

    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.

  9. Unconventional Fermi surface in an insulating state

    SciTech Connect

    Harrison, Neil; Tan, B. S.; Hsu, Y. -T.; Zeng, B.; Hatnean, M. Ciomaga; Zhu, Z.; Hartstein, M.; Kiourlappou, M.; Srivastava, A.; Johannes, M. D.; Murphy, T. P.; Park, J. -H.; Balicas, L.; Lonzarich, G. G.; Balakrishnan, G.; Sebastian, Suchitra E.

    2015-07-17

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

  10. Origin of outer rings in lunar multi-ringed basins - Evidence from morphology and ring spacing

    NASA Technical Reports Server (NTRS)

    Head, J. W.

    1977-01-01

    The reported investigation has the objective to examine both the morphology and morphometry of several of the freshest lunar basins including Orientale, Imbrium, Nectaris, Crisium, and Humorum, and to compare the characteristics of their three most prominent rings to features in smaller craters. On the basis of comparisons it is concluded that the outer basin ring forms within the region where significant structural uplift of the basin rim is to be expected. Therefore the formation of the outer ring scarp may be closely associated with structural uplift of the inner portion of the crater rim flank. According to a model suggested for the origin of the outer two rings, the cratering event formed two inner rings, a central peak ring, and an uplifted crater rim crest, with deposition of ejecta during the process.

  11. Orbital Magnetization of Quantum Spin Hall Insulator Nanoparticles.

    PubMed

    Potasz, P; Fernández-Rossier, J

    2015-09-01

    Both spin and orbital degrees of freedom contribute to the magnetic moment of isolated atoms. However, when inserted in crystals, atomic orbital moments are quenched because of the lack of rotational symmetry that protects them when isolated. Thus, the dominant contribution to the magnetization of magnetic materials comes from electronic spin. Here we show that nanoislands of quantum spin Hall insulators can host robust orbital edge magnetism whenever their highest occupied Kramers doublet is singly occupied, upgrading the spin edge current into a charge current. The resulting orbital magnetization scales linearly with size, outweighing the spin contribution for islands of a few nm in size. This linear scaling is specific of the Dirac edge states and very different from Schrodinger electrons in quantum rings. By modeling Bi(111) flakes, whose edge states have been recently observed, we show that orbital magnetization is robust with respect to disorder, thermal agitation, shape of the island, and crystallographic direction of the edges, reflecting its topological protection.

  12. Coulomb impurity scattering in topological insulator thin films

    SciTech Connect

    Yin, Gen; Wickramaratne, Darshana; Lake, Roger K.; Zhao, Yuanyuan

    2014-07-21

    Inter-surface coupling in thin-film topological insulators can reduce the surface state mobility by an order of magnitude in low-temperature transport measurements. The reduction is caused by a reduction in the group velocity and an increased s{sub z} component of the surface-state spin which weakens the selection rule against large-angle scattering. An intersurface potential splits the degenerate bands into a Rashba-like bandstructure. This reduces the intersurface coupling, it largely restores the selection rule against large angle scattering, and the ring-shaped valence band further reduces backscattering by requiring, on average, larger momentum transfer for backscattering events. The effects of temperature, Fermi level, and intersurface potential on the Coulomb impurity scattering limited mobility are analyzed and discussed.

  13. Black ring deconstruction

    SciTech Connect

    Gimon, Eric; Gimon, Eric G.; Levi, Thomas S.

    2007-06-22

    We present a sample microstate for a black ring in four and five dimensional language. The microstate consists of a black string microstate with an additional D6-brane. We show that with an appropriate choice of parameters the piece involving the black string microstate falls down a long AdS throat, whose M-theory lift is AdS_3 x S2. We wrap a spinning dipole M2-brane on the S2 in the probe approximation. In IIA, this corresponds to a dielectric D2-brane carrying only D0-charge. We conjecture this is the firstapproximation to a cloud of D0-branes blowing up due to their non-abelian degrees of freedom and the Myers effect.

  14. Protection against telomeric position effects by the chicken cHS4 beta-globin insulator.

    PubMed

    Rincón-Arano, Héctor; Furlan-Magaril, Mayra; Recillas-Targa, Félix

    2007-08-28

    Epigenetic silencing of genes relocated near telomeres, termed telomeric position effect, has been extensively studied in yeast and more recently in vertebrates. However, protection of a transgene against telomeric position effects by chromatin insulators has not yet been addressed. In this work we investigated the capacity of the chicken beta-globin insulator cHS4 to shield a transgene against silencing by telomeric heterochromatin. Using telomeric repeats, we targeted transgene integration into telomeres of the chicken cell line HD3. When the chicken cHS4 insulator is incorporated to the transgene, we observe a sustained gene expression of single-copy integrants that can be maintained for >100 days of continuous culture. However, uninsulated single-copy clones showed an accelerated gene expression extinction profile. Unexpectedly, telomeric silencing was not reversed with trichostatin A or nicotidamine. In contrast, significant reactivation was obtained with 5-aza-2'-deoxycytidine, consistent with the subtelomeric DNA methylation status. Strikingly, insulated transgenes integrated into telomeric regions were enriched in histone methylation, such as H3K4me2 and H3K79me2, but not in histone acetylation. Furthermore, the cHS4 insulator counteracts telomeric position effects in an upstream stimulatory factor-independent manner. Our results suggest that this insulator has the capacity to adapt to different chromatin propagation signals in distinct insertional epigenome environments.

  15. Gas insulated substation equipment for industrial applications

    SciTech Connect

    Kenedy, J.J.

    1984-11-01

    Until recently the only available method for construction of high voltage systems was to use exposed air insulated equipment supported on porcelain columns. The past decade has witnessed the introduction and wide acceptance of compressed gas insulated equipment as a viable alternative to the conventional substation system. The characteristics of gas insulated substations (GIS) and their application for industrial use at service voltages at 69 kV and above are discussed.

  16. DC CHARACTERIZATION OF HIGH GRADIENT MULTILAYER INSULATORS

    SciTech Connect

    Watson, J A; Caporaso, G J; Sampayan, S E; Sanders, D M; Krogh, M L

    2005-05-26

    We have developed a novel insulator concept that involves the use of alternating layers of conductors and insulators with periods less than 1 mm. We have demonstrated that these structures perform 2 to 5 times better than conventional insulators in long pulse, short pulse, and alternating polarity applications. We present new testing results showing exceptional behavior at DC, with gradients in excess of 110kV/cm in vacuum.

  17. Instrumented Sheath Insulator Experiment (IFAC-SI)

    NASA Astrophysics Data System (ADS)

    Lee, Celia; Miskolczy, Gabor; Lieb, David P.; Witt, Tony

    The Instrumented Fast-Reactor Accelerated Component-Sheath Insulator test (IFAC-SI) is a key experiment of the Thermionic Fuel Element Verification Program designed to allow continuous monitoring of sheath insulator specimens with an applied voltage during the in-reactor test. This paper describes the IFAC-SI experiment test setting, including shear insulator samples, heat pipes, fins, and enclosing container, and discusses the thermal models and their effects on the experimental design.

  18. 49 CFR 179.201-11 - Insulation.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 49 Transportation 3 2011-10-01 2011-10-01 false Insulation. 179.201-11 Section 179.201-11...-Pressure Tank Car Tanks (Classes DOT-111AW and 115AW) § 179.201-11 Insulation. (a) Insulation shall be of sufficient thickness so that the thermal conductance at 60 °F. is not more than 0.075 Btu per hour,...

  19. Floating insulated conductors for heating subsurface formations

    DOEpatents

    Burns, David; Goodwin, Charles R.

    2014-07-29

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

  20. Aerogels Insulate Missions and Consumer Products

    NASA Technical Reports Server (NTRS)

    2008-01-01

    Aspen Aerogels, of Northborough, Massachusetts, worked with NASA through an SBIR contract with Kennedy Space Center to develop a robust, flexible form of aerogel for cryogenic insulation for space shuttle launch applications. The company has since used the same manufacturing process developed under the SBIR award to expand its product offerings into the more commercial realms, making the naturally fragile aerogel available for the first time as a standard insulation that can be handled and installed just like standard insulation.

  1. Adaptive Management

    EPA Science Inventory

    Adaptive management is an approach to natural resource management that emphasizes learning through management where knowledge is incomplete, and when, despite inherent uncertainty, managers and policymakers must act. Unlike a traditional trial and error approach, adaptive managem...

  2. The Saturn Ring Observer: In situ studies of planetary rings

    NASA Astrophysics Data System (ADS)

    Nicholson, P. D.; Tiscareno, M. S.; Spilker, L. J.

    2010-12-01

    As part of the Planetary Science Decadal Survey recently undertaken by the NRC's Space Studies Board for the National Academy of Sciences, studies were commissioned for a number of potential missions to outer planet targets. One of these studies examined the technological feasibility of a mission to carry out in situ studies of Saturn's rings, from a spacecraft placed in a circular orbit above the ring plane: the Saturn Ring Observer. The technical findings and background are discussed in a companion poster by T. R. Spilker et al. Here we outline the science goals of such a mission. Most of the fundamental interactions in planetary rings occur on spatial scales that are unresolved by flyby or orbiter spacecraft. Typical particle sizes in the rings of Saturn are in the 1 cm - 10 m range, and average interparticle spacings are a few meters. Indirect evidence indicates that the vertical thickness of the rings is as little as 5 - 10 m, which implies a velocity dispersion of only a few mm/sec. Theories of ring structure and evolution depend on the unknown characteristics of interparticle collisions and on the size distribution of the ring particles. The SRO could provide direct measurements of both the coefficient of restitution -- by monitoring individual collisions -- and the particles’ velocity dispersion. High-resolution observations of individual ring particles should also permit estimates of their spin states. Numerical simulations of Saturn’s rings incorporating both collisions and self-gravity predict that the ring particles are not uniformly distributed, but are instead clustered into elongated structures referred to as “self-gravity wakes”, which are continually created and destroyed on an orbital timescale. Theory indicates that the average separation between wakes in the A ring is of order 30-100 m. Direct imaging of self-gravity wakes, including their formation and subsequent dissolution, would provide critical validation of these models. Other

  3. Magnetic fields in ring galaxies

    NASA Astrophysics Data System (ADS)

    Moss, D.; Mikhailov, E.; Silchenko, O.; Sokoloff, D.; Horellou, C.; Beck, R.

    2016-07-01

    Context. Many galaxies contain magnetic fields supported by galactic dynamo action. The investigation of these magnetic fields can be helpful for understanding galactic evolution; however, nothing definitive is known about magnetic fields in ring galaxies. Aims: Here we investigate large-scale magnetic fields in a previously unexplored context, namely ring galaxies, and concentrate our efforts on the structures that appear most promising for galactic dynamo action, i.e. outer star-forming rings in visually unbarred galaxies. Methods: We use tested methods for modelling α-Ω galactic dynamos, taking into account the available observational information concerning ionized interstellar matter in ring galaxies. Results: Our main result is that dynamo drivers in ring galaxies are strong enough to excite large-scale magnetic fields in the ring galaxies studied. The variety of dynamo driven magnetic configurations in ring galaxies obtained in our modelling is much richer than that found in classical spiral galaxies. In particular, various long-lived transients are possible. An especially interesting case is that of NGC 4513, where the ring counter-rotates with respect to the disc. Strong shear in the region between the disc and the ring is associated with unusually strong dynamo drivers in such counter-rotators. The effect of the strong drivers is found to be unexpectedly moderate. With counter-rotation in the disc, a generic model shows that a steady mixed parity magnetic configuration that is unknown for classical spiral galaxies, may be excited, although we do not specifically model NGC 4513. Conclusions: We deduce that ring galaxies constitute a morphological class of galaxies in which identification of large-scale magnetic fields from observations of polarized radio emission, as well as dynamo modelling, may be possible. Such studies have the potential to throw additional light on the physical nature of rings, their lifetimes, and evolution.

  4. Sclerotic Rings in Mosasaurs (Squamata: Mosasauridae): Structures and Taxonomic Diversity

    PubMed Central

    Yamashita, Momo; Konishi, Takuya; Sato, Tamaki

    2015-01-01

    Mosasaurs (Squamata: Mosasauridae) were a highly diverse, globally distributed group of aquatic lizards in the Late Cretaceous (98–66 million years ago) that exhibited a high degree of adaptation to life in water. To date, despite their rich fossil record, the anatomy of complete mosasaur sclerotic rings, embedded in the sclera of the eyeball, has not been thoroughly investigated. We here describe and compare sclerotic rings of four mosasaur genera, Tylosaurus, Platecarpus, Clidastes, and Mosasaurus, for the first time. Two specimens of Tylosaurus and Platecarpus share an exact scleral ossicle arrangement, excepting the missing portion in the specimen of Platecarpus. Furthermore, the exact arrangement and the total count of 14 ossicles per ring are shared between Tylosaurus and numerous living terrestrial lizard taxa, pertaining to both Iguania and Scleroglossa. In contrast, two species of Mosasaurus share the identical count of 12 ossicles and the arrangement with each other, while no living lizard taxa share exactly the same arrangement. Such a mosaic distribution of these traits both among squamates globally and among obligatorily aquatic mosasaurs specifically suggests that neither the ossicle count nor their arrangement played major roles in the aquatic adaptation in mosasaur eyes. All the mosasaur sclerotic rings examined consistently exhibit aperture eccentricity and the scleral ossicles with gently convex outer side. Hitherto unknown to any squamate taxa, one specimen of Platecarpus unexpectedly shows a raised, concentric band of roughened surface on the inner surface of the sclerotic ring. It is possible that one or both of these latter features may have related to adaptation towards aquatic vision in mosasaurs, but further quantitative study of extant reptilian clades containing both terrestrial and aquatic taxa is critical and necessary in order to understand possible adaptive significances of such osteological features. PMID:25692667

  5. Thermal Insulation Strips Conserve Energy

    NASA Technical Reports Server (NTRS)

    2009-01-01

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

  6. Electrostatic Separation Of Layers In Thermal Insulation

    NASA Technical Reports Server (NTRS)

    Bhandari, Pradeep

    1995-01-01

    Layers in multilayer insulation charged to keep them separated by electrostatic repulsion, eliminating need for spacer nets. Removal of spacer nets reduces conduction of heat between layers. Insulation in question type used to slow leakage of heat into Dewar flasks containing liquid helium. Proposal originally applied to insulation in cryogenic cooling subsystems of infrared-detector systems in outer space, also appears applicable to small panels of insulation for terrestrial cryogenic equipment, provided layers contained in evacuated spaces and weight of each layer small fraction of electrostatic force upon it.

  7. Systems and Methods for Providing Insulation

    NASA Technical Reports Server (NTRS)

    Golden, Johnny L. (Inventor)

    2015-01-01

    Systems and methods provide a multi-layer insulation (MLI) that includes a plurality of sealed metalized volumes in a stacked arrangement, wherein the plurality of sealed metalized volumes encapsulate a gas therein, with the gas having one of a thermal insulating property, an acoustic insulating property, or a combination insulating property thereof. The MLI also includes at least one spacer between adjacent sealed metalized volumes of the plurality of sealed metalized volumes and a protective cover surrounding the plurality of sealed metalized volumes.

  8. Inspecting Pipe Radiographically Through Asbestos Insulation

    NASA Technical Reports Server (NTRS)

    Gianettino, David P.

    1994-01-01

    Welds between sections of insulated steampipe located and inspected radiographically. Unless need to repair defective weld, one avoids cost, time, and hazard of removing asbestos insulation. Enables inspectors to locate and evaluate nondestructively any weld in pipe system, without shutting down steam. Hidden weld joints first located by use of low-power fluoroscope, moved along pipe while technician observes fluoroscopic image. Low-energy x rays from fluoroscope penetrate insulation but not pipe. Weld bead appears in silhouette on fluoroscope screen. Technician then accurately marks weld sites on insulation for later inspection.

  9. Insulating coatings (excluding electrical insulation). (Latest citations from World Surface Coatings Abstracts database). Published Search

    SciTech Connect

    Not Available

    1993-08-01

    The bibliography contains citations concerning compositions and methods of applying coatings that provide insulation. Thermal and acoustic insulation are stressed. Electrically insulating coatings are covered in another bibliography. Paint, films, asbestos, fiber, and plastic coatings are examined. Citations of selected patents are included. Insulation coatings designed for cement, pipes, walls, roofs, building interiors and exteriors, and vehicles are described. (Contains a minimum of 195 citations and includes a subject term index and title list.)

  10. The KACST Heavy-Ion Electrostatic Storage Ring

    SciTech Connect

    Almuqhim, A. A.; Alshammari, S. M.; El Ghazaly, M. O. A.; Papash, A. I.; Welsch, C. P.

    2011-10-27

    A novel Electrostatic Storage Ring (ESR) for beams at energies up to 30keV/q is now being constructed at the National Centre for Mathematics and Physics (NCMP), King Abdul-Aziz City for Science and Technology (KACST). The ring is designed to be the core of a highly flexible experimental platform that will combine a large package of complementary beam techniques for atomic and molecular physics and related fields. The lattice design had to cover the different experimental techniques that the ring will be equipped with, such as e.g. Electron-Ion, Laser-Ion, Ion-Ion or Ion-Neutral beams, in both crossed and merged-beam configurations. The development of such an ESR is realized in a staged approach, in which a simple and early-run adaptation of the ring is built first, and then this basic version is upgraded to a higher symmetry of the ultimate version of the ring. Here, we report a general overview of this technical development with a focus on the layout of the first built stage of the ring.

  11. Fully synthetic taped insulation cables

    DOEpatents

    Forsyth, E.B.; Muller, A.C.

    1983-07-15

    The present invention is a cable which, although constructed from inexpensive polyolefin tapes and using typical impregnating oils, furnishes high voltage capability up to 765 kV, and has such excellent dielectric characteristics and heat transfer properties that it is capable of operation at capacities equal to or higher than presently available cables at a given voltage. This is accomplished by using polyethylene, polybutene or polypropylene insulating tape which has been specially processed to attain properties which are not generally found in these materials, but are required for their use in impregnated electrical cables. Chief among these properties is compatibility with impregnating oil.

  12. Processing of insulators and semiconductors

    SciTech Connect

    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.

  13. Insulating panels with rice husk

    SciTech Connect

    Salas, J.; Veras, J.

    1986-01-01

    This study includes the quantitative results of tests caried out on 7.5 x 15.0 cm cylindrical test pieces and fullsized panels with a cement and rice husk, produced by using means belonging to the so-called ''appropriate technologies''. These results are summarized and analyzed with a view to providing a possible alternative for substituting other insulating materials, which are generally imported, in developing countries. The technical results presented point towards a promising future for the task undertaken, within the context of a research project on ''materials, technologies and prototypes for very low-cost housing'' which, in a - multinational capacity, is being developed at the Instituto E. Torroja.

  14. Reversible Seeding in Storage Rings

    SciTech Connect

    Ratner, Daniel; Chao, Alex; /SLAC

    2011-12-14

    We propose to generate steady-state microbunching in a storage ring with a reversible seeding scheme. High gain harmonic generation (HGHG) and echo-enabled harmonic generation (EEHG) are two promising methods for microbunching linac electron beams. Because both schemes increase the energy spread of the seeded beam, they cannot drive a coherent radiator turn-by-turn in a storage ring. However, reversing the seeding process following the radiator minimizes the impact on the electron beam and may allow coherent radiation at or near the storage ring repetition rate. In this paper we describe the general idea and outline a proof-of-principle experiment. Electron storage rings can drive high average power light sources, and free-electron lasers (FELs) are now producing coherent light sources of unprecedented peak brightness While there is active research towards high repetition rate FELs (for example, using energy recovery linacs), at present there are still no convenient accelerator-based sources of high repetition rate, coherent radiation. As an alternative avenue, we recently proposed to establish steady-state microbunching (SSMB) in a storage ring. By maintaining steady-state coherent microbunching at one point in the storage ring, the beam generates coherent radiation at or close to the repetition rate of the storage ring. In this paper, we propose a method of generating a microbunched beam in a storage ring by using reversible versions of linac seeding schemes.

  15. Biomechanics of Corneal Ring Implants

    PubMed Central

    2015-01-01

    Purpose: To evaluate the biomechanics of corneal ring implants by providing a related mathematical theory and biomechanical model for the treatment of myopia and keratoconus. Methods: The spherical dome model considers the inhomogeneity of the tunica of the eye, dimensions of the cornea, lamellar structure of the corneal stroma, and asphericity of the cornea. It is used in this study for calculating a strengthening factor sf for the characterization of different ring-shaped corneal implant designs. The strengthening factor is a measure of the amount of strengthening of the cornea induced by the implant. Results: For ring segments and incomplete rings, sf = 1.0, which indicates that these implants are not able to strengthen the cornea. The intracorneal continuous complete ring (MyoRing) has a strengthening factor of up to sf = 3.2. The MyoRing is, therefore, able to strengthen the cornea significantly. Conclusions: The result of the presented biomechanical analysis of different ring-shaped corneal implant designs can explain the different postoperative clinical results of different implant types in myopia and keratoconus. PMID:26312619

  16. Running Rings Around the Web.

    ERIC Educational Resources Information Center

    McDermott, Irene E.

    1999-01-01

    Describes the development and current status of WebRing, a service that links related Web sites into a central hub. Discusses it as a viable alternative to other search engines and examines issues of free speech, use by the business sector, and implications for WebRing after its purchase by Yahoo! (LRW)

  17. How Jupiter's Ring Was Discovered.

    ERIC Educational Resources Information Center

    Elliot, James; Kerr, Richard

    1985-01-01

    "Rings" (by astronomer James Elliot and science writer Richard Kerr) is a nontechnical book about the discovery and exploration of ring systems from the time of Galileo to the era of the Voyager spacecraft. One of this book's chapters is presented. (JN)

  18. Fibre ring cavity semiconductor laser

    SciTech Connect

    Duraev, V P; Medvedev, S V

    2013-10-31

    This paper presents a study of semiconductor lasers having a polarisation maintaining fibre ring cavity. We examine the operating principle and report main characteristics of a semiconductor ring laser, in particular in single- and multiple-frequency regimes, and discuss its application areas. (lasers)

  19. The rare-RI ring

    NASA Astrophysics Data System (ADS)

    Ozawa, A.; Uesaka, T.; Wakasugi, M.; Rare-RI Ring Collaboration

    2012-12-01

    We describe the rare-RI (radioactive isotope) ring at the RI Beam Factory (RIBF). The main purpose of the rare-RI ring is to measure the mass of very neutron-rich nuclei, the production rates of which are very small (hence ‘rare RI’) and the lifetimes of which are predicted to be very short. In the rare-RI ring, there are two innovative pieces of apparatus: individual injection, which can realize the injection of 200 A MeV rare RIs one by one, and a cyclotron-like storage ring, which allows high isochronous magnetic fields with large angular and momentum acceptances. With these devices, we will achieve a 10-6 mass resolution, and will be able to access rare RIs, the production rate of which is down to 1 event/day/pnA. Construction of the rare-RI ring started in fiscal year 2012.

  20. 21 CFR 880.6200 - Ring cutter.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Ring cutter. 880.6200 Section 880.6200 Food and....6200 Ring cutter. (a) Identification. A ring cutter is a device intended for medical purposes that is used to cut a ring on a patient's finger so that the ring can be removed. The device incorporates...

  1. 21 CFR 880.6200 - Ring cutter.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Ring cutter. 880.6200 Section 880.6200 Food and....6200 Ring cutter. (a) Identification. A ring cutter is a device intended for medical purposes that is used to cut a ring on a patient's finger so that the ring can be removed. The device incorporates...

  2. 21 CFR 880.6200 - Ring cutter.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Ring cutter. 880.6200 Section 880.6200 Food and....6200 Ring cutter. (a) Identification. A ring cutter is a device intended for medical purposes that is used to cut a ring on a patient's finger so that the ring can be removed. The device incorporates...

  3. 21 CFR 880.6200 - Ring cutter.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Ring cutter. 880.6200 Section 880.6200 Food and....6200 Ring cutter. (a) Identification. A ring cutter is a device intended for medical purposes that is used to cut a ring on a patient's finger so that the ring can be removed. The device incorporates...

  4. 21 CFR 880.6200 - Ring cutter.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Ring cutter. 880.6200 Section 880.6200 Food and....6200 Ring cutter. (a) Identification. A ring cutter is a device intended for medical purposes that is used to cut a ring on a patient's finger so that the ring can be removed. The device incorporates...

  5. RADIATION MONITOR CONTAINING TWO CONCENTRIC IONIZATION CHAMBERS AND MEANS FOR INSULATING THE SEPARATE CHAMBERS

    DOEpatents

    Braestrup, C.B.; Mooney, R.T.

    1964-01-21

    This invention relates to a portable radiation monitor containing two concentric ionization chambers which permit the use of standard charging and reading devices. It is particularly adapted as a personnel x-ray dosimeter and to this end comprises a small thin walled, cylindrical conductor forming an inner energy dependent chamber, a small thin walled, cylindrical conductor forming an outer energy independent chamber, and polymeric insulation means which insulates said chambers from each other and holds the chambers together with exposed connections in a simple, trouble-free, and compact assembly substantially without variation in directional response. (AEC)

  6. Utilizing a silicon-photonic micro-ring-resonator and multi-ring scheme for wavelength-switchable erbium fiber laser in single-longitudinal-mode

    NASA Astrophysics Data System (ADS)

    Yeh, Chien-Hung; Hsu, Yung; Chow, Chi-Wai

    2016-06-01

    In this paper, a stable and wavelength-switchable silicon-photonic erbium-doped fiber (EDF) triple-ring laser is proposed and demonstrated. In the experiment, the integration of a silicon-on-insulator (SOI)-based grating coupler and silicon-micro-ring-resonator (SMRR) are coupled and connected to the proposed EDF triple-ring laser for generating wavelength. Here, the output wavelength can be adjusted in a wavelength range of 1529.8 –1561.8 nm with a 2.0 nm tuning step according to the free spectrum range (FSR) of the SMRR. Moreover, the stability performance of the output power and wavelength are also discussed and analyzed.

  7. Fireplace adapters

    SciTech Connect

    Hunt, R.L.

    1983-12-27

    An adapter is disclosed for use with a fireplace. The stove pipe of a stove standing in a room to be heated may be connected to the flue of the chimney so that products of combustion from the stove may be safely exhausted through the flue and outwardly of the chimney. The adapter may be easily installed within the fireplace by removing the damper plate and fitting the adapter to the damper frame. Each of a pair of bolts has a portion which hooks over a portion of the damper frame and a threaded end depending from the hook portion and extending through a hole in the adapter. Nuts are threaded on the bolts and are adapted to force the adapter into a tight fit with the adapter frame.

  8. Interfacing Topological Insulators with Ferromagnetism

    NASA Astrophysics Data System (ADS)

    Richardella, Anthony

    In topological insulators, the surface states arise from strong spin-orbit coupling while the degeneracy of the Dirac point is protected by time reversal symmetry. Introducing magnetism in proximity to the surface states breaks this symmetry, destroying the non-trivial Berry phase at the Dirac point and leads to a hedgehog spin texture near the newly opened magnetic gap. This symmetry broken phase leads to a host of unusual physics, such as the quantum anomalous Hall (QAH) effect. In this talk, we discuss the growth by molecular beam epitaxy and characterization of such magnetically interfaced and magnetically doped topological insulators. Such materials often suffer from structural defects and interfacial layers, as well as from degradation during device fabrication. In particular, it is shown that Cr doped (Bi1-x,Sbx)2Te3 can exhibit perfect Hall quantization at low temperatures despite these defects. However, the magnetic ordering of this material was found to be quite unusual, displaying a super-paramagnetic like character, perhaps reflecting this disorder. Such observations highlight the surprising behavior of such broken symmetry phases in topological materials. This work was performed in collaboration with A. Kandala, M. Liu, W. Wang, N.P. Ong, C.-X. Liu, and N. Samarth, in addition to the authors of the references cited. This work was supported by funding from ARO/MURI, DARPA and ONR.

  9. Sialons as high temperature insulators

    NASA Technical Reports Server (NTRS)

    Phillips, W. M.; Kuo, Y. S.

    1978-01-01

    Sialons were evaluated for application as high temperature electrical insulators in contact with molybdenum and tungsten components in hard vacuum applications. Both D.C. and variable frequency A.C. resistivity data indicate the sialons to have electrical resistivity similar to common oxide in the 1000 C or higher range. Metallographic evaluations indicate good bonding of the type 15R ALN polytype to molybdenum and tungsten. The beta prime or modified silicon nitride phase was unacceptable in terms of vacuum stability. Additives effect on electrical resistivity. Similar resistivity decreases were produced by additions of molybdenum or tungsten to form cermets. The use of hot pressing at 1800 C with ALN, Al2 O3 and Si3N4 starting powders produced a better product than did a combination of SiO2 and AIN staring powders. It was indicated that sialons will be suitable insulators in the 1600K range in contact with molybdenum or tungsten if they are produced as a pure ceramic and subsequently bonded to the metal components at temperatures in the 1600K range.

  10. Sheath insulator test thermal analysis

    NASA Astrophysics Data System (ADS)

    Lee, Celia C. M.

    Thermal models were developed for Instrumented Fast Reactor Component Sheath Insulator (IFAC-SI) test to aid in the design and fabrication of the experiment which is part of the Thermionic Fuel Element Verification Program. The actual experiment with two heat pipes in one test capsule is described by Miskolczy and Lee (1990). Two-dimensional finite element models were used in conjunction with other explicit programs to determine the necessary fin design and argon filling conditions of the vapor controlled heat pipes used to maintain desired operating temperatures. Four two-dimensional finite element models were developed: an axisymmetric capsule model; a radial sheath insulator model; a radial fin model, and an axial fin model. All finite element models were verified by comparing results between models and explicit one-dimensional heat-flow calculations. This thermal analysis package of 2D FEMs and explicit programs predicts the best geometry and placement of fins to compensate for uncertainties from internal gamma heating, emissivity of niobium, and outer sodium temperature.

  11. Sheath insulator test thermal analysis

    NASA Astrophysics Data System (ADS)

    Lee, Celia C. M.

    1991-01-01

    Thermal models were developed for Instrumented Fast Reactor Component Sheath Insulator (IFAC-SI) test to aid in the design and fabrication of the experiment which is part of the Thermionic Fuel Element (TFE) Verification Program. The actual experiment with two heat pipes in one test capsule is described by Miskolczy and Lee (1990). Two-dimensional finite element models were used in conjunction with other explicit programs to determine the necessary fin design and argon filling conditions of the vapor controlled heat pipes used to maintain desired operating temperatures. Four two-dimensional finite element models were developed: an axisymmetric capsule model; a radial sheath insulator model; a radial fin model, and an axial fin model. All finite element models were verified by comparing results between models and explicity one-dimensional heat-flow calculations. Additional programs were written to calculate the thermal expansion of the capsule components and argon volumes for operating temperatures. This thermal analysis package of two-dimensional finite element models and explicit programs predicts the best geometry and placement of fins to compensate for uncertainties from internal gamma heating, emissivity of niobium, and outer sodium temperature.

  12. Charge and spin topological insulators

    SciTech Connect

    Kopaev, Yu. V. Gorbatsevich, A. A.; Belyavskii, V. I.

    2011-09-15

    The topologically nontrivial states of matter-charge and spin topological insulators, which exhibit, respectively, properties of the integer quantum Hall effect and the quantum spin Hall effect-are discussed. The topological characteristics (invariant with respect to weak adiabatic changes in the Hamiltonian parameters) which lead to such states are considered. The model of a 2D hexagonal lattice having symmetries broken with respect to time reversal and spatial inversion which was proposed by Haldane and marked the beginning of unprecedented activity in the study of topologically nontrivial states is discussed. This model relates the microscopic nature of the symmetry breaking with respect to the time reversal to the occurrence of spontaneous orbital currents which circulate within a unit cell. Such currents become zero upon summation over the unit cell, but they may form spreading current states at the surface which are similar to the edge current states under the quantum Hall effect. The first model of spontaneous currents (exciton insulator model) is considered, and the possibility of implementing new topologically nontrivial states in this model is discussed.

  13. Low-cost exterior insulation process and structure

    DOEpatents

    Vohra, A.

    1999-03-02

    A low-cost exterior insulation process of stacking bags of insulating material against a wall and covering them with wire mesh and stucco provides a durable structure with good insulating value. 2 figs.

  14. 79 FR 60188 - Nonmetallic Thermal Insulation for Austenitic Stainless Steel

    Federal Register 2010, 2011, 2012, 2013, 2014

    2014-10-06

    ... COMMISSION Nonmetallic Thermal Insulation for Austenitic Stainless Steel AGENCY: Nuclear Regulatory... of the NRC considers acceptable when selecting and using nonmetallic thermal insulation in the..., ``Nonmetallic Thermal Insulation for Austenitic Stainless Steel,'' is temporarily identified by its task...

  15. Ring Buffered Network Bus

    NASA Technical Reports Server (NTRS)

    1997-01-01

    This report describes the research effort to demonstrate the integration of a data sharing technology, Ring Buffered Network Bus, in development by Dryden Flight Research Center, with an engine simulation application, the Java Gas Turbine Simulator, in development at the University of Toledo under a grant from the Glenn Research Center. The objective of this task was to examine the application of the RBNB technologies as a key component in the data sharing, health monitoring and system wide modeling elements of the NASA Aviation Safety Program (AVSP) [Golding, 1997]. System-wide monitoring and modeling of aircraft and air safety systems will require access to all data sources which are relative factors when monitoring or modeling the national airspace such as radar, weather, aircraft performance, engine performance, schedule and planning, airport configuration, flight operations, etc. The data sharing portion of the overall AVSP program is responsible for providing the hardware and software architecture to access and distribute data, including real-time flight operations data, among all of the AVSP elements. The integration of an engine code capable of numerically "flying" through recorded flight paths and weather data using a software tool that allows for distributed access of data to this engine code demonstrates initial steps toward building a system capable of monitoring and modeling the National Airspace.

  16. Triple-glazed insulating unit with improved edge insulation

    DOEpatents

    Goodwin, George B.; Buchanan, Michael J.

    2016-06-07

    An insulating unit includes a first spacer frame between first and second sheets, e.g. glass sheets, and a second spacer frame between the second sheet and a third sheet. A first surface of the first spacer frame is adhered to inner surface of the first sheet, and an opposite second surface of the first spacer frame is adhered to a first surface of the second sheet, by a moisture impervious adhesive layer. A first outer surface of the second spacer frame is adhered to a second surface of the second sheet, and an opposite second outer surface of the second spacer frame is adhered to an inner surface of the third sheet, by the adhesive layer. The first spacer frame and the second spacer frame have an offset of greater than zero.

  17. Improved insulator layer for MIS devices

    NASA Technical Reports Server (NTRS)

    Miller, W. E.

    1980-01-01

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

  18. Insulator (Heat and Frost). Occupational Analyses Series.

    ERIC Educational Resources Information Center

    McRory, Aline; Ally, Mohamed

    This analysis covers tasks performed by an insulator, an occupational title some provinces and territories of Canada have also identified as heat and frost insulator. A guide to analysis discusses development, structure, and validation method; scope of the occupation; trends; and safety. To facilitate understanding the nature of the occupation,…

  19. 49 CFR 179.300-4 - Insulation.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 49 Transportation 3 2013-10-01 2013-10-01 false Insulation. 179.300-4 Section 179.300-4 Transportation Other Regulations Relating to Transportation (Continued) PIPELINE AND HAZARDOUS MATERIALS SAFETY...-Unit Tank Car Tanks (Classes DOT-106A and 110AW) § 179.300-4 Insulation. (a) Tanks shall not...

  20. 49 CFR 179.300-4 - Insulation.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 49 Transportation 2 2010-10-01 2010-10-01 false Insulation. 179.300-4 Section 179.300-4 Transportation Other Regulations Relating to Transportation PIPELINE AND HAZARDOUS MATERIALS SAFETY... Specifications for Multi-Unit Tank Car Tanks (Classes DOT-106A and 110AW) § 179.300-4 Insulation. (a) Tanks...

  1. 49 CFR 179.300-4 - Insulation.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 49 Transportation 3 2014-10-01 2014-10-01 false Insulation. 179.300-4 Section 179.300-4 Transportation Other Regulations Relating to Transportation (Continued) PIPELINE AND HAZARDOUS MATERIALS SAFETY...-Unit Tank Car Tanks (Classes DOT-106A and 110AW) § 179.300-4 Insulation. (a) Tanks shall not...

  2. 49 CFR 179.300-4 - Insulation.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 49 Transportation 3 2012-10-01 2012-10-01 false Insulation. 179.300-4 Section 179.300-4 Transportation Other Regulations Relating to Transportation (Continued) PIPELINE AND HAZARDOUS MATERIALS SAFETY...-Unit Tank Car Tanks (Classes DOT-106A and 110AW) § 179.300-4 Insulation. (a) Tanks shall not...

  3. 49 CFR 179.300-4 - Insulation.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 49 Transportation 3 2011-10-01 2011-10-01 false Insulation. 179.300-4 Section 179.300-4 Transportation Other Regulations Relating to Transportation (Continued) PIPELINE AND HAZARDOUS MATERIALS SAFETY...-Unit Tank Car Tanks (Classes DOT-106A and 110AW) § 179.300-4 Insulation. (a) Tanks shall not...

  4. Topological insulators: A romance with many dimensions

    NASA Astrophysics Data System (ADS)

    Manoharan, Hari C.

    2010-07-01

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

  5. Classification of Topological Insulators and Superconductors

    NASA Astrophysics Data System (ADS)

    Schnyder, Andreas P.; Ryu, Shinsei; Furusaki, Akira; Ludwig, Andreas W. W.

    2009-05-01

    An exhaustive classification scheme of topological insulators and superconductors is presented. The key property of topological insulators (superconductors) is the appearance of gapless degrees of freedom at the interface/boundary between a topologically trivial and a topologically non-trivial state. Our approach consists in reducing the problem of classifying topological insulators (superconductors) in d spatial dimensions to the problem of Anderson localization at a (d-1) dimensional boundary of the system. We find that in each spatial dimension there are precisely five distinct classes of topological insulators (superconductors). The different topological sectors within a given topological insulator (superconductor) can be labeled by an integer winding number or a Z2 quantity. One of the five topological insulators is the "quantum spin Hall" (or: Z2 topological) insulator in d = 2, and its generalization in d = 3 dimensions. For each dimension d, the five topological insulators correspond to a certain subset of five of the ten generic symmetry classes of Hamiltonians introduced more than a decade ago by Altland and Zirnbauer in the context of disordered systems (which generalizes the three well known "Wigner and Dyson" symmetry classes).

  6. Advanced Space Suit Insulation Feasibility Study

    NASA Technical Reports Server (NTRS)

    Trevino, Luis A.; Orndoff, Evelyne S.

    2000-01-01

    For planetary applications, the space suit insulation has unique requirements because it must perform in a dynamic mode to protect humans in the harsh dust, pressure and temperature environments. Since the presence of a gaseous planetary atmosphere adds significant thermal conductance to the suit insulation, the current multi-layer flexible insulation designed for vacuum applications is not suitable in reduced pressure planetary environments such as that of Mars. Therefore a feasibility study has been conducted at NASA to identify the most promising insulation concepts that can be developed to provide an acceptable suit insulation. Insulation concepts surveyed include foams, microspheres, microfibers, and vacuum jackets. The feasibility study includes a literature survey of potential concepts, an evaluation of test results for initial insulation concepts, and a development philosophy to be pursued as a result of the initial testing and conceptual surveys. The recommended focus is on microfibers due to the versatility of fiber structure configurations, the wide choice of fiber materials available, the maturity of the fiber processing industry, and past experience with fibers in insulation applications

  7. Cotton-Fiber-Filled Rubber Insulation

    NASA Technical Reports Server (NTRS)

    Anderson, Floyd A.

    1987-01-01

    Carbonization of fibers at high temperatures improves strength and erosion resistance. Cotton linters tested as replacement for asbestos filler currently used in rubber insulation in solid rocket motors. Cotton-filled rubber insulation has industrial uses; in some kinds of chemical- or metal-processing equipment, hoses, and protective clothing.

  8. Reflecting layers reduce weight of insulation

    NASA Technical Reports Server (NTRS)

    Cole, J. D.; Schlessinger, E. D.; Rockoff, H. J.

    1981-01-01

    Metalized films placed between layers of fibrous material maintain equivalent thermal conductivity while cutting blanket density in half. Tests indicate that insulation with 1 lb/cu ft density with goldized films has thermal conductivity equal to 2 lb/cu ft of conventional insulation. Concept reduces weight in commercial aircraft and increases cargo space.

  9. Uniform insulation applied-B ion diode

    DOEpatents

    Seidel, David B.; Slutz, Stephen A.

    1988-01-01

    An applied-B field extraction ion diode has uniform insulation over an anode surface for increased efficiency. When the uniform insulation is accomplished with anode coils, and a charge-exchange foil is properly placed, the ions may be focused at a point on the z axis.

  10. Insulation board and process of making

    DOEpatents

    Nowobilski, J.J.; Owens, W.J.

    1985-08-27

    Insulation board is described which is capable of bearing a load without significant loss of insulating capacity due to compression, produced by a method wherein the board is made in compliance with specified conditions of time, temperature and pressure. 2 figs.

  11. Wrapped multilayer insulation for cryogenic piping

    NASA Astrophysics Data System (ADS)

    Dye, Scott; Kopelove, Alan; Mills, Gary L.

    2012-06-01

    Many cryogenic systems require thermal insulation on piping and tubing containing cryogenic fluids. The lowest heat leak is typically achieved with conventional multilayer insulation (MLI) wrapped around the tubing and contained in a vacuum. However, because of inherent insulation compression and its effect on conventional netting spacer MLI, MLI performance on piping and tubing is four to ten times worse than MLI on a cryogenic tank or flat surface. Wrapped Multilayer Insulation (WMLI) is a high performance multilayer insulation designed for cryogenic piping that uses an innovative discrete spacer technology to control layer spacing/density and reduce heat leak. This paper reports on the initial development of WMLI and its demonstration as a feasible technology. The WMLI design was estimated in thermal models to provide four times better thermal insulation than conventional MLI on cryogenic piping. A WMLI prototype was built and had a measured heat leak 37% of the heat leak of conventional MLI insulating tubing. Test results for WMLI are presented, and plans for continued development of this insulation are discussed.

  12. Ion Rings for Magnetic Fusion

    SciTech Connect

    Greenly, John, B.

    2005-07-31

    This Final Technical Report presents the results of the program, Ion Rings for Magnetic Fusion, which was carried out under Department of Energy funding during the period August, 1993 to January, 2005. The central objective of the program was to study the properties of field-reversed configurations formed by ion rings. In order to reach this objective, our experimental program, called the Field-reversed Ion Ring Experiment, FIREX, undertook to develop an efficient, economical technology for the production of field-reversed ion rings. A field-reversed configuration (FRC) in which the azimuthal (field-reversing) current is carried by ions with gyro-radius comparable to the magnetic separatrix radius is called a field-reversed ion ring. A background plasma is required for charge neutralization of the ring, and this plasma will be confined within the ring's closed magnetic flux. Ion rings have long been of interest as the basis of compact magnetic fusion reactors, as the basis for a high-power accelerator for an inertial fusion driver, and for other applications of high power ion beams or plasmas of high energy density. Specifically, the FIREX program was intended to address the longstanding question of the contribution of large-orbit ions to the observed stability of experimental FRCs to the MHD tilt mode. Typical experimental FRCs with s {approx} 2-4, where s is the ratio of separatrix radius to ion gyro-radius, have been stable to tilting, but desired values for a fusion reactor, s > 20, should be unstable. The FIREX ring would consist of a plasma with large s for the background ions, but with s {approx} 1 for the ring ions. By varying the proportions of these two populations, the minimum proportion of large-orbit ions necessary for stability could be determined. The incorporation of large-orbit ions, perhaps by neutral-beam injection, into an FRC has been advanced for the purpose of stabilizing, heating, controlling angular momentum, and aiding the formation of a

  13. Particle properties and processes in Uranus' rings

    NASA Technical Reports Server (NTRS)

    Esposito, L. W.; Brahic, A.; Burns, J. A.; Marouf, Essam A.

    1991-01-01

    The particle properties and processes in the Uranian rings are analyzed from Voyager observations and ground-based data. Occultation observations of the epsilon ring are interpreted to yield an effective size of the ring particles that exceeds 70 cm, a surface mass density that exceeds 80 g/sq cm, and a ring vertical thickness greater than tens of meters for solid ice particles. The particles forming the classic rings are dark and gray, with albedo of 0.014 +/-0.004. It is argued that the small amount of dust that exists in the classical rings and between the rings in bands is created by erosion of ring particles and unseen satellites resulting from collisions and micrometeoroid bombardment. As proposed for regions of the other known ring systems, new ring material can be continually created by the destruction of small moons near the rings, which may explain the youthful appearance of the Uranian rings.

  14. Entrainment in interacting vortex rings

    NASA Astrophysics Data System (ADS)

    Shami, Rammah; Ganapathisubramani, Bharathram

    2014-11-01

    The efficiency of entrainment in single vortex rings has been examined by various studies in the literature. These studies have shown that this efficiency is greatly increased for smaller stroke-time to nozzle-diameter ratios, L/D. However, no clear consensus exists regarding the effect on the entrainment process for the sectioned delivery of the vortex forming impulse. In the present work the entrainment mechanism associated with the interaction between two co-axially separated vortex rings is explored. Planar, time-resolved particle image velocimetry (PIV) measurements are taken of a interacting vortex flow field. Lagrangian coherent structures (LCS) extracted from the finite-time Lyapunov exponent (FTLE) fields are employed to determine the vortex boundaries of the interacting rings and is then used to measure entrainment. Preliminary results indicate that whilst the most efficient entrainment of ambient fluid by the ring pairs occurs at larger separations, the rate and overall mass transport increase can be controlled by altering the spatial/temporal separation between successive rings and is higher at smaller ring spacing. Variation in mass transport behaviour for different ring strengths (L/D) and Reynolds numbers will also be discussed.

  15. SIMULATION STUDY AND INITIAL TEST OF THESNS RING RF SYSTEM

    SciTech Connect

    Zhang, Yan; Ma, Hengjie; Holmes, Jeffrey A; Champion, Mark; Chu, Paul; Cousineau, Sarah M; Hardek, Thomas W; Plum, Michael A; Danilov, Viatcheslav; Piller, Chip

    2008-01-01

    The rfsimulator code was developed for the study of the Spallation Neutron Source (SNS) dual-harmonic ring RF control. It uses time-domain solvers to compute beam-cavity interactions and FFT methods to simulate the time responses of the linear RF system. The important elements of the system considered in the model include beam loading, dynamic cavity detuning, circuit bandwidth, loop delay, proportional-integral controller for feedback and adaptive feed forward, stochastic noise, width-in-turn loop parameter change, beam current fluctuation, and bunch leakage. As the beam power increases, beam loss in the ring goes up and thus precise control of the bunching RF phase and amplitude is required to limit beam loss. The code will help in the development of a functional RF control and in achieving the goal of minimizing beam loss in the accumulator ring.

  16. Modeling piston-ring dynamics, blowby, and ring-twist effects

    SciTech Connect

    Tian, T.; Noordzij, L.B.; Wong, V.W.; Heywood, J.B.

    1996-12-31

    A ring-dynamics and gas-flow model has been developed to study ring/groove contact, blowby, and the influence of ring static twist, keystone ring/groove configurations, and other piston and ring parameters. The model is developed for a ring pack with three rings. The dynamics of the top two rings and the gas pressures in the regions above the oil control ring are simulated. Distributions of oil film thickness and surface roughness on the groove and ring surfaces are assumed in the model to calculate the forces generated by the ring/groove contact. Ring static and dynamic twists are considered as well as different keystone ring/groove configurations. Ring dynamics and gas flows are coupled in the formulation and an implicit scheme is implemented, enabling the model to resolve detailed events such as ring flutter. Studies on a spark ignition engine found that static twist or, more generally speaking, the relative angle between rings and their grooves, has great influence on ring/groove contact characteristics, ring stability, and blowby. Ring flutter is found to occur for the second ring with a negative static twist under normal operating conditions and for the top ring with a negative static twist under high-speed/low-load operating conditions. Studies on a diesel engine show that different keystone ring/groove configurations result in different twist behaviors of the ring that may affect the wear pattern of the keystone ring running surfaces.

  17. Electrically Tunable Magnetism in Magnetic Topological Insulators.

    PubMed

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

    2015-07-17

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

  18. ITER CENTRAL SOLENOID COIL INSULATION QUALIFICATION

    SciTech Connect

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

    2009-06-11

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

  19. Insulator Surface Flashover Due to UV Illumination

    SciTech Connect

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

    2009-07-27

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

  20. Comments on collision mechanics in ring systems. [planetary rings

    NASA Technical Reports Server (NTRS)

    Hartmann, W. K.

    1982-01-01

    Collisions within planetary ring systems, especially Saturn's, are discussed. The particles may have coherent icy cores and less coherent granular or frosty surface layers, consistent with thermal eclipse observations. Collisions do not cause catastrophic fragmentation of the particles, although minor surface erosion and reaccretion is possible. Evolution by collisional fragmentation is thus not as important as in the asteroid belt. Models suggest that the fractional number of projectile masses dislodged when solid (or solid-core) projectiles strike solid ice or granular surface layers does not exceed the order of 10 to the minus 7th to minus 9th power. Even at this rate, the half life of ring particles would be less than the age of the solar system in crowded ring regions unless there was very efficient reaccretion. A plausible ring particle model involves solid ice cores with granular surface layers that exchange material by slow erosion and efficient reaccretion; the granular layers protect the cores from rapid erosion.