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Sample records for 600k wls fibers

  1. Radiation damage in WLS fibers

    SciTech Connect

    David, M.; Gomes, A.; Maio, A.; Santos, J.; Varanda, M.

    1998-11-09

    Several types of WLS fibers, candidates to be used in the TILECAL/ATLAS detector, were irradiated in a {sup 60}Co {gamma} source. Bicron, Kuraray and Pol.Hi.Tech fibers were exposed to a total dose of {approx}150 Krad. The degradation of light output was measured just after irradiation and followed during several days. The results are presented.

  2. Radiation damage in WLS fibers

    NASA Astrophysics Data System (ADS)

    David, M.; Gomes, A.; Maio, A.; Santos, J.; Varanda, M.

    1998-11-01

    Several types of WLS fibers, candidates to be used in the TILECAL/ATLAS detector, were irradiated in a 60Co γ source. Bicron, Kuraray and Pol.Hi.Tech fibers were exposed to a total dose of ˜150 Krad. The degradation of light output was measured just after irradiation and followed during several days. The results are presented.

  3. Light collection from scintillation counters using WLS fibers and bars

    SciTech Connect

    Evdokimov, V.

    1998-01-01

    Several methods of collecting light on scintillation counters using WLS fibers and WLS bars were studied. Nearly 20 prototype counters with different designs and with sizes ranging from 14{times}11{times}1.3cm{sup 3} to 105{times}60{times}1.3cm{sup 3} have been tested using cosmic muons and radioactive source. The efficiency of light collection on number of photoelectrons, uniformity of response, and time resolution have been measured. Test results for two new designs of light collection from scintillator based on WLS fibers around perimeter of scintillator plate and WLS fibers placed in machined on scintillator plate deep grooves are presented. Two out of the studied designs have been chosen as the basic options for the D0 muon system upgrade: light collection using two WLS bars for the forward muon scintillation counters and light collection using WLS fibers in deep grooves on scintillator for central area muon counters.

  4. Dose rate effects in WLS fibers

    NASA Astrophysics Data System (ADS)

    Maio, A.; David, M.; Gomes, A.

    1997-03-01

    The radiation hardness of different types of WLS fibers produced by BICRON, KURARAY and POL.HI.TECH has been systematically studied. Low dose rate irradiations (from 0.55 krad/h up to 4 krad/h and total dose of about 140 krad) were performed with a 60Co γ source. The results are compared with high dose rate irradiations (1.5 Mrad/h and total dose of 1 Mrad) in a mixed field of 20% of neutrons and 80% of γ's in a nuclear reactor. The degradation of the optical properties of fibers with different composition, namely different Ultraviolet absorber (UVA) concentration and different type of cladding are studied. Dose rate effects are investigated as well as the effect of irradiation with different type of particles. The UVA can help on the radiation hardness, but no permanent dose rate effects, or special effects due to the neutron component of the irradiation field were observed.

  5. Radiation hardness of 3HF-tile/O2-WLS-fiber calorimeter

    SciTech Connect

    Han, S.W.; Hu, L.D.; Liu, N.Z.

    1993-11-01

    The radiation hardness of a 3HF-tile/O2-WLS-fiber calorimeter with two different tile/fiber patterns has been studied. Two calorimeter modules were irradiated up to 10 Mrad with the BEPC 1.3 GeV electron beam. The radiation damage of these modules is compared with our previous measurements from SCSN81-tile/BCF91A-WLS-fiber modules. The longitudinal damage profiles are fitted as a function of depth.

  6. Final results from the SDC dopant search for new green wavelength shifting (WLS) fibers: Volume 1

    SciTech Connect

    Pla-Dalmau, A.; Foster, G.W.; Zhang, G.

    1993-12-01

    A scintillating tile/fiber design had been selected for the SDC calorimeter. It consisted of scintillator plates embedded with a wavelength shifting (WLS) fiber which was spliced to a clear fiber. Based on the results from previous radiation damage studies on different scintillating materials, SCSN38 had been chosen for the scintillating tile and BCF91 or Y7 for the WLS fiber. SCSN38 is a blue-emitting scintillator and both WLS fibers use K-27, a green-emitting compound, as dopant. K-27 has a decay time of approximately 12 ns which is long in comparison to that of most blue-emitting materials. Of all the factors that affect the speed of the scintillator tile/fiber calorimeter, the lifetime of the green-emitting dopant is the dominant component. To increase the speed of the calorimeter, it would be desirable that the green WLS fibers utilized had lifetimes between 3 and 5 ns. However, currently available green WLS fibers exhibit decay times between 7 and 12 ns. Development of new green-emitting WLS fibers with short decay times must be investigated. The goal of this project was to search for commercially available fluorescent compounds with {lambda}{sub abs} = 400--450 nm, {lambda}{sub em} = 450--550 nm, {tau} = 3--7 ns, and quantum efficiency of minimum 0.7 (current K-27 baseline). Large Stokes shift and low self-absorption were not important requirements since the optical pathlength for the shifted light was small. Characterization of the spectroscopic properties of these compounds after styrene polymerization is important since this is an essential part of the manufacturing of WLS fibers. This summary presents the transmittance and fluorescence data for each dopant tested. However, many fluorescence measurements using different excitation wavelengths and orientations were recorded. Volume 1 presents a plot for each dopant combining transmittance and the most representative fluorescence measurement.

  7. Detection of the Light Produced in Scintillating Tiles by Means of a Wls Fiber and AN Avalanche Photodiode Working in the Geiger Mode

    NASA Astrophysics Data System (ADS)

    Akindinov, A.; Mal'Kevich, D.; Martemiyanov, A.; Smirnitsky, A.; Voloshin, K.; Grigoriev, E.; Golovin, V.; Bondarenko, G.

    2004-07-01

    Plates of an organic scintillator BC408, 50 × 50 × 5 mm3, with a wavelength-shifting (WLS) fiber Kuraray Y11, embedded in circular grooves inside the plastic, were used in combination with 1 mm2 avalanche photodiodes working in the Geiger mode (APDg or MRS-APD). Beam tests with minimum ionizing particles (MIP), performed at the ITEP synchrotron, have shown high detection efficiencies (about 13 photo-electrons).

  8. The use of WLS fibers in a hadronic calorimeter for the HyperCP experiment

    SciTech Connect

    Durandet, C.; Dukes, E.C.; Holmstrom, T.; Huang, M.; Nelson, K.S.; Rajaram, D.; Saleh, N.; Tzamouranis, Y.; Crisler, M.

    1998-11-01

    Preliminary results are presented on the operational aspects of an iron-scintillator sampling hadronic calorimeter used in the HyperCP experiment at Fermilab during the 1996-1997 fixed target run. The calorimeter used wavelength shifter fibers for light collection from scintillator sheets. Details of how the 2 m{times}2 mm fibers were polished, sputtered, and used for the readout are discussed. The average reflectivity of the sputtered fibers was 0.85{plus_minus}0.05, and the average attenuation lengths were 3.48{plus_minus}0.34 m. The calorimeter was designed to trigger on the proton (anti-proton) from {Lambda}({bar {Lambda}}) decays, suppressing triggers from secondary interactions and background muons. {copyright} {ital 1998 American Institute of Physics.}

  9. Digital signal processing for a thermal neutron detector using ZnS(Ag):6LiF scintillating layers read out with WLS fibers and SiPMs

    NASA Astrophysics Data System (ADS)

    Mosset, J.-B.; Stoykov, A.; Greuter, U.; Hildebrandt, M.; Schlumpf, N.

    2016-07-01

    We present a digital signal processing system based on a photon counting approach which we developed for a thermal neutron detector consisting of ZnS(Ag):6LiF scintillating layers read out with WLS fibers and SiPMs. Three digital filters have been evaluated: a moving sum, a moving sum after differentiation and a digital CR-RC4 filter. The performances of the detector with these filters are presented. A full analog signal processing using a CR-RC4 filter has been emulated digitally. The detector performance obtained with this analog approach is compared with the one obtained with the best performing digital approach.

  10. WISCONSIN LONGITUDINAL STUDY (WLS)

    EPA Science Inventory

    The Wisconsin Longitudinal Study (WLS) is a long-term study of a random sample of 10,317 men and women who graduated from Wisconsin high schools in 1957. The WLS provides an opportunity to study of the life course, intergenerational transfers and relationships, family functioning...

  11. Detection of thermal neutrons using ZnS(Ag):6LiF neutron scintillator read out with WLS fibers and SiPMs

    NASA Astrophysics Data System (ADS)

    Hildebrandt, M.; Stoykov, A.; Mosset, J.-B.; Greuter, U.; Schlumpf, N.

    2016-07-01

    In this paper we present the development of a one-dimensional multi-channel thermal neutron detection system for the application in neutron scattering instrumentation, e.g. strain-scanning diffractometers. The detection system is based on ZnS(Ag):6LiF neutron scintillator with embedded WLS fibers which are read out with a SiPM. A dedicated signal processing system allows us to suppress the SiPM dark counts and to extract the signals from the neutron absorption events. For a single-channel detection unit which represents the elementary building block of this detection system we achieved a neutron detection efficiency of ~65% at 1.2 Å, a background count rate <10-3 Hz and a gamma-sensitivity <10-6 (measured with a 60Co source), while the dead time is ~20 μs and the multi-count ratio is < 1 %. This performance was achieved even for SiPM dark count rates of up to ~2 MHz.

  12. Development of a 600 kJ HTS SMES

    NASA Astrophysics Data System (ADS)

    Seong, K. C.; Kim, H. J.; Kim, S. H.; Sim, K. D.; Sohn, M. H.; Lee, E. Y.; Park, S. J.; Hahn, S. Y.; Park, M. W.

    2008-09-01

    This paper describes an overview of development on a 600 kJ high-temperature superconducting magnetic energy storage (HTS SMES). Our final goal will be the commercialization of MJ class HTS SMES system for the increase of power quality within 5 years. Hence, for this purpose, we have developed the research and development in 3 years. The purpose of this research is to develop a pilot system, which can protect the sensitivity loads from a momentary power interruption or a voltage sag.

  13. Fast scintillation counters with WLS bars

    SciTech Connect

    Bezzubov, V.; Denisov, S.; Dyshkant, A.; Evdokimov, V.; Galyaev, A.; Goncharov, P.; Gurzhiev, S.; Kostritsky, A.; Kozelov, A.; Stoianova, D.; Denisov, D.; Diehl, H.T.; Ito, A.S.; Johns, K.

    1998-11-01

    The Do/ collaboration is building 4608 scintillation counters to upgrade forward muon system for the next Fermilab Collider run. Each counter consists of 12.7 mm thick scintillator plate with two WLS bars along two sides for the light collection. With average 10{sup 2} photoelectrons from {ital mip} particle the counters provide time resolution below 1ns and have good energy resolution. Results of Bicron 404A scintillator and Kumarin 30 WLS aging under irradiation up to 3Mrad are presented. With specially designed magnetic shielding counters can operate in magnetic filed up to 500G. {copyright} {ital 1998 American Institute of Physics.}

  14. Development of 600 kV triple resonance pulse transformer.

    PubMed

    Li, Mingjia; Zhang, Faqiang; Liang, Chuan; Xu, Zhou

    2015-06-01

    In this paper, a triple-resonance pulse transformer based on an air-core transformer is introduced. The voltage across the high-voltage winding of the air-core transformer is significantly less than the output voltage; instead, the full output voltage appears across the tuning inductor. The maximum ratio of peak load voltage to peak transformer voltage is 2.77 in theory. By analyzing pulse transformer's lossless circuit, the analytical expression for the output voltage and the characteristic equation of the triple-resonance circuit are presented. Design method for the triple-resonance pulse transformer (iterated simulation method) is presented, and a triple-resonance pulse transformer is developed based on the existing air-core transformer. The experimental results indicate that the maximum ratio of peak voltage across the load to peak voltage across the high-voltage winding of the air-core transformer is approximately 2.0 and the peak output voltage of the triple-resonance pulse transformer is approximately 600 kV. PMID:26133858

  15. Cohort Profile: Wisconsin longitudinal study (WLS)

    PubMed Central

    Herd, Pamela; Carr, Deborah; Roan, Carol

    2014-01-01

    The Wisconsin Longitudinal Study (WLS) is a longitudinal study of men and women who graduated from Wisconsin high schools in 1957 and one of their randomly selected siblings. Wisconsin is located in the upper midwest of the United States and had a population of approximately 14 000 000 in 1957, making it the 14th most populous state at that time. Data spanning almost 60 years allow researchers to link family background, adolescent characteristics, educational experiences, employment experiences, income, wealth, family formation and social and religious engagement to midlife and late-life physical health, mental health, psychological well-being, cognition, end of life planning and mortality. The WLS is one of the few longitudinal data sets that include an administrative measure of cognition from childhood. Further, recently collected saliva samples allow researchers to explore the inter-relationships among genes, behaviours and environment, including genetic determinants of behaviours (e.g. educational attainment); the interactions between genes and environment; and how these interactions predict behaviours. Most panel members were born in 1939, and the sample is broadly representative of White, non-Hispanic American men and women who have completed at least a high school education. Siblings cover several adjoining cohorts: they were born primarily between 1930 and 1948. At each interview, about two-thirds of the sample lived in Wisconsin, and about one-third lived elsewhere in the United States or abroad. The data, along with documentation, are publicly accessible and can be accessed at http://www.ssc.wisc.edu/wlsresearch/. Requests for protected data or assistance should be sent to wls@ssc.wisc.edu. PMID:24585852

  16. 75 FR 18871 - Agency Information Collection Activities: Form N-600K, Revision of a Currently Approved...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-04-13

    ... From the Federal Register Online via the Government Publishing Office DEPARTMENT OF HOMELAND SECURITY U.S. Citizenship and Immigration Services Agency Information Collection Activities: Form N-600K, Revision of a Currently Approved Information Collection; Comment Request ACTION: 60-Day Notice of Information Collection under Review: Form N-...

  17. Comparative study of WLS fibres for the ATLAS Tile Calorimeter

    NASA Astrophysics Data System (ADS)

    Gomes, A.; David, M.; Henriques, A.; Maio, A.

    1998-02-01

    The Wave Length Shifting (WLS) fibres are one of the most important components of the ATLAS barrel hadronic tile calorimeter (Tilecal). The fibres collect the hght produced in the injection molded scintillating tiles and transport it to the photomultipliers. Parameters like attenuation length and light yield are important, as well as flexibility and radiation hardness. Comparative results of WLS fibres produced by Bicron, Kuraray and Pol.Hi.Tech are presented. The performance of the fibres BCF91A from Bicron and S048 from Pol.Hi.Tech was significatively improved, but the most performant are still the double clad Y11 fibres from Kuraray.

  18. Comparative study of WLS fibres for the ATLAS tile calorimeter

    NASA Astrophysics Data System (ADS)

    Gomes, A.; David, M.; Henriques, A.; Maio, A.

    1997-02-01

    The Wave Length Shifting (WLS) fibres are one of the most important components of the ATLAS barrel hadronic tile calorimeter (Tilecal). The fibres collect the light produced in the injection molded scintillating tiles and transport it to the photomultipliers. Parameters like attenuation length and light yield are important, as well as flexibility and radiation hardness. Comparative results of WLS fibres produced by Bicron, Kuraray and Pol.Hi.Tech are presented. The performance of the fibres BCF91A from Bicron and S048 from Pol.Hi.Tech was significatively improved, but the most performant are still the double clad Y11 fibres from Kuraray.

  19. 600 kV modulator design for the SLAC Next Linear Collider Test Accelerator

    SciTech Connect

    Harris, K.; de Lamare, J.; Nesterov, V.; Cassel, R.

    1992-07-01

    Preliminary design for the SLAC Next Linear Collider Test Accelerator (NLCTA) requires a pulse power source to produce a 600 kV, 600 A, 1.4 {mu}s, 0.1% flat top pulse with rise and fall times of approximately 100 ns to power an X-Band klystron with a microperveance of 1.25 at {approx} 100 MW peak RF power. The design goals for the modulator, including those previously listed, are peak modulator pulse power of 340 MW operating at 120 Hz. A three-stage darlington pulse-forming network, which produces a >100 kV, 1.4 {mu}s pulse, is coupled to the klystron load through a 6:1 pulse transformer. Careful consideration of the transformer leakage inductance, klystron capacitance, system layout, and component choice is necessary to produce the very fast rise and fall times at 600 kV operating continuously at 120 Hz.

  20. The Workplace Literacy System Project (WLS). Final Performance Report.

    ERIC Educational Resources Information Center

    Poulton, Bruce R.

    The Workplace Literacy System Project (WLS) prepared interactive CD-ROM discs containing about 50 hours of instruction and drill in basic skills presented within the context of the textile/apparel manufacturing industry. The project was conducted at a Sara Lee knit products plant in North Carolina. During the project, literacy task analyses were…

  1. Analysis of eddy current losses during discharging period in a 600 kJ SMES

    NASA Astrophysics Data System (ADS)

    Park, M. J.; Kwak, S. Y.; Lee, S. Y.; Kim, W. S.; Lee, J. K.; Park, C.; Choi, K.; Bae, J. H.; Kim, S. H.; Sim, K. D.; Seong, K. C.; Jung, H. K.; Hahn, S.

    2008-09-01

    The operation of the SMES system can be divided into three modes such as charging, operating and discharging. During the charging and the discharging modes, a magnetic field variation due to the current increase and decrease generate eddy current losses in the SMES system. The eddy current loss in discharging mode is the major factor to be considered because the operating time in the mode is fixed, whereas the charging mode has the arbitrary operating time which is not fixed. In this paper, we present the analysis results of the eddy current losses which are generated in the 600 kJ class HTS SMES system during the discharging mode.

  2. Measurement and control of single spins in diamond above 600 K

    NASA Astrophysics Data System (ADS)

    Toyli, David M.

    2013-03-01

    The nitrogen vacancy (NV) center in diamond stands out among spin qubit systems in large part because its spin can be controlled under ambient conditions whereas most other solid state qubits operate only at cryogenic temperatures. However, despite the intense interest in the NV center's room temperature properties for nanoscale sensing and quantum information applications, the ultimate thermal limits to its measurement and control have been largely unknown. We demonstrate that the NV center's spin can be optically addressed and coherently controlled at temperatures exceeding 600 K and show that its addressability is eventually limited by thermal quenching of the optical spin readout. These measurements, in combination with computational studies, provide important information about the electronic states that facilitate the optical spin measurement and, moreover, suggest that the coherence of the NV center's spin states could be utilized for thermometry. We infer that single spins in diamond offer temperature sensitivities better than 100 mK/√{ Hz} up to 600 K using conventional sensing techniques and show that advanced measurement schemes provide a pathway to reach 10 mK/√{ Hz} sensitivities. Together with diamond's ideal thermal and mechanical properties, these results suggest that NV center thermometers could be applied in cellular thermometry and scanning thermal microscopy. This work was funded by AFOSR, ARO, and DARPA.

  3. Noise radiation characteristics of the Westinghouse WWG-0600 (600kW) wind turbine generator

    NASA Technical Reports Server (NTRS)

    Shepherd, Kevin P.; Hubbard, Harvey H.

    1989-01-01

    Acoustic data are presented from five different WWG-0600 machines for the wind speed range 6.7 to 13.4 m/s, for a power output range of 51 to 600 kW and for upwind, downwind and crosswind locations. Both broadband and narrowband data are presented and are compared with calculations and with similar data from other machines. Predicted broadband spectra are in good agreement with measurements at high power and underestimate them at low power. Discrete frequency rotational noise components are present in all measurements and are believed due to terrain induced wind gradients. Predictions are in general agreement with measurements upwind and downwind but underestimate them in the crosswind direction.

  4. The 600K T9 dwarfs: analysis of the spectral energy distributions

    SciTech Connect

    Saumon, Didier; Leggett, Sandy K; Burningham, Ben; Cushing, Michael C; Marley, Mark S; Pinfield, David J; Smart, Richard L; Warren, Stephen J

    2008-01-01

    We present 8--15 {mu}m spectra of ULAS J003402.77-005206.7, and extremely late-type T dwarf. We fit synthetic spectra to the near- through mid-infrared energy distribution of this dwarf, as well as to the near-infrared spectra of two similar dwarfs, ULAS J133553.45+113005.2 and CFBDS J005910.82-011401.3. The fit to ULAS J133553.45+113005.2 is constrained using mid-infrared photometry. We derive effective temperatures of 550--600 K for all three of these T9 dwarfs; ULAS J003402.77-005206.7 appears to be the least massive (5--30 M{sub Jup}), and CFBDS J005910.82-011401.3 the most massive (30--50 M{sub Jup}).

  5. Design and test results of a 600-kW tetrode amplifier for the Superconducting Super Collider

    SciTech Connect

    Rees, D.E.; Brittain, D.L. ); Grippe, J.M.; Marrufo, O. )

    1993-01-01

    This paper describes the design and testing of a pulsed 600-kW tetrode amplifier that will be used to drive a radiofrequency quadrupole (RFQ) for the Superconducting Super Collider (SSC). Three stages of amplification provide a nominal gain of 77 dB and peak output power of 600 kW. The amplifier is operated at a pulse width of 100 [mu]s and a repetition frequency of 10 Hz. This paper presents the rf design and calculated operating conditions for the amplifier. Details of the electrical design are presented, along with test results.

  6. Design and test results of a 600-kW tetrode amplifier for the Superconducting Super Collider

    SciTech Connect

    Rees, D.E.; Brittain, D.L.; Grippe, J.M.; Marrufo, O.

    1993-05-01

    This paper describes the design and testing of a pulsed 600-kW tetrode amplifier that will be used to drive a radiofrequency quadrupole (RFQ) for the Superconducting Super Collider (SSC). Three stages of amplification provide a nominal gain of 77 dB and peak output power of 600 kW. The amplifier is operated at a pulse width of 100 {mu}s and a repetition frequency of 10 Hz. This paper presents the rf design and calculated operating conditions for the amplifier. Details of the electrical design are presented, along with test results.

  7. A 600-kV double-pulser for the PHERMEX electron gun

    SciTech Connect

    Carlson, R.L.; Kang, M.; Melton, J.G.; Seitz, G.J.; Trujillo, L.T.

    1997-09-01

    The PHERMEX (Pulsed High Energy Radiographic Machine Emitting X-rays) Radiographic Facility is a 50-MHz, 3-Cavity, RF-Linac driven by a pulsed, thermionic electron-gun Injector. The PHERMEX is used to take flash radiographs using x-rays at a single time in an explosively driven event. To investigate the time evolution of these events requires two things: (1) a multiple-pulser to drive the electron-gun Injector and (2) a large-format, gamma-ray, camera system to record a scintillator at the different times. The authors report the recent success of developing a reliable double-pulser that consists of two Marx generators that independently charge two PFLs that are switched out at about 1.4 MV. The PFLs are connected in series by large diaphragm switches that are independently laser triggered by two quadrupled-YAG lasers. Recent tests of the system into a dummy load, produced two high quality 600 kV pulses separated by 1.0 {micro}s. Each pulse has a FWHM of 90 ns, a 50 ns flat-top {+-} 3%, and a risetime of 25 ns and a falltime of 35 ns. The interpulse time is variable up to about 275 {micro}s; the first switch is kept closed by a keep alive inductor. The system has produced a 50 shot sequence of two pulses with a 1-sigma jitter < 1 ns. The system has been modeled using TOSCA-3D, FLUX-2D, and a transmission line model run with the circuits code Micro-CAP.

  8. Convergence analysis of WLS based solution of Navier Stokes equation

    NASA Astrophysics Data System (ADS)

    Kosec, G.

    2016-06-01

    A numerical solution of a Navier-Stokes problem based on the Weighted Least Squares (WLS) approximation of velocity and pressure fields is presented in this paper. The approximation function is constructed over the local support, i.e., a sub cluster of computational nodes. Besides local approximation of the fields also the pressure-velocity algorithm is constructed locally. The presented solution procedure is demonstrated on two classical fluid-flow benchmark tests, i.e., lid-driven cavity and backward-facing step problem. The method is validated through comparison against already published data on regular nodal distributions and convergence analyses. In addition the method is also tested on irregular nodal distributions. Results are presented in terms of cross-section velocity profiles and convergence plots.

  9. Comparison of calculated and experimental thermal attachment rate constants for SF6 in the temperature range 200-600 K

    NASA Technical Reports Server (NTRS)

    Orient, O. J.; Chutjian, A.

    1986-01-01

    Electron-attachment cross sections are calcualted for the process e(-) + SF6 yields SF6(-) in the energy range 1-200 meV. An electron scattering approximation is used in which diatomiclike potential energy curves near the equilibrium SF6 ground state are constructed from recent spectroscopic data. Excellent agreement is found over the entire energy range with experimental attachment cross sections at a temperature of 300 K for s-wave (l = 0) scattering. The same calculation, with appropriate adjustment of the thermal populations, is used to calculate attachment rate constants in the range 50-600 K for both s- and p-wave scattering.

  10. Rheology of ɛ-iron up to 19 GPa and 600 K in the D-DIA

    NASA Astrophysics Data System (ADS)

    Nishiyama, Norimasa; Wang, Yanbin; Rivers, Mark L.; Sutton, Steve R.; Cookson, David

    2007-12-01

    Stress-strain curves, i.e., relations between the differential stress and macroscopic sample strain, of polycrystalline ɛ-iron have been obtained at pressures of 17(±1) GPa, three different temperatures (600, 400, and 300 K), and various strain rates between 3.8 × 10-6 and 2.3 × 10-5 s-1 using the deformation-DIA coupled with monochromatic X-rays. Five independent stress-strain curves were obtained on axial shortening and the sample exhibited ductile behavior in all. Above 4% axial strain, sample stresses reach saturation and the sample exhibited steady-state deformation. Stress exponents at temperatures of 400 and 600 K were determined to be ˜31 and ˜7, respectively. These results indicate that ɛ-iron deforms in plasticity regime below 400 K and that the dominant deformation mechanism at 600 K may be low temperature power-law creep. The overall deformation behavior for ɛ-iron is consistent with that of zinc, suggesting that the deformation mechanism map of ɛ-iron resembles those of other hexagonal metals.

  11. Rheology of $\\varepsilon$-iron up to 19 GPa and 600 K in the D-DIA

    NASA Astrophysics Data System (ADS)

    Nishiyama, Norimasa; Wang, Yanbin; Rivers, Mark L.; Sutton, Steve R.; Cookson, David

    2007-12-01

    Stress-strain curves, i.e., relations between the differential stress and macroscopic sample strain, of polycrystalline $\\varepsilon$-iron have been obtained at pressures of 17(+/-1) GPa, three different temperatures (600, 400, and 300 K), and various strain rates between 3.8 × 10-6 and 2.3 × 10-5 s-1 using the deformation-DIA coupled with monochromatic X-rays. Five independent stress-strain curves were obtained on axial shortening and the sample exhibited ductile behavior in all. Above 4% axial strain, sample stresses reach saturation and the sample exhibited steady-state deformation. Stress exponents at temperatures of 400 and 600 K were determined to be ~31 and ~7, respectively. These results indicate that $\\varepsilon$-iron deforms in plasticity regime below 400 K and that the dominant deformation mechanism at 600 K may be low temperature power-law creep. The overall deformation behavior for $\\varepsilon$-iron is consistent with that of zinc, suggesting that the deformation mechanism map of $\\varepsilon$-iron resembles those of other hexagonal metals.

  12. Iterative methods for the WLS state estimation on RISC, vector, and parallel computers

    SciTech Connect

    Nieplocha, J.; Carroll, C.C.

    1993-10-01

    We investigate the suitability and effectiveness of iterative methods for solving the weighted-least-square (WLS) state estimation problem on RISC, vector, and parallel processors. Several of the most popular iterative methods are tested and evaluated. The best performing preconditioned conjugate gradient (PCG) is very well suited for vector and parallel processing as is demonstrated for the WLS state estimation of the IEEE standard test systems. A new sparse matrix format for the gain matrix improves vector performance of the PCG algorithm and makes it competitive to the direct solver. Internal parallelism in RISC processors, used in current multiprocessor systems, can be taken advantage of in an implementation of this algorithm.

  13. Rheology of hcp-iron up to 19 GPa and 600 K in the D-DIA

    NASA Astrophysics Data System (ADS)

    Nishiyama, N.; Wang, Y.; Rivers, M. L.; Sutton, S. R.; Cookson, D.

    2007-12-01

    Stress-strain curves, i.e., relations between the differential stress and macroscopic sample strain, of polycrystalline hcp-iron have been obtained at pressures up to 19 GPa, three different temperatures (600, 400, and 300 K), and various strain rates using the deformation-DIA coupled with monochromatic X-rays. The experiment was carried out at the GSECARS bending magnet beamline 13-BM-D at the Advanced Photon Source (Argonne, IL, USA). We used two sintered diamond anvils on the down-stream side in the DDIA, to serve as windows for diffracted X-rays. The starting material was a bcc-iron rod (0.5 mm in diameter and 0.6 mm in length). The generated temperature was inferred from the input power using a power-temperature relation which had been determined in a separate run. The cell assembly was pressurized isotropically up to a load of 50 tons. At this load, the sample was still bcc-phase and the generated pressure was about 15 GPa. At this fixed load, the sample was heated up to 700 K, and the phase transition from bcc to hcp was observed. After the synthesis of hcp-phase, five independent stress-strain curves were obtained on axial shortening and the sample exhibited ductile behavior in all. Above 4 percent axial strain, sample stresses reach saturation and the sample exhibited steady-state deformation. Stress exponents at temperatures of 400 and 600 K were determined to be 31 and 7, respectively. These results indicate that hcp-iron deforms in plasticity regime below 400 K and that the dominant deformation mechanism at 600 K may be low temperature power-law creep. The overall deformation behavior for hcp-iron is consistent with that of zinc, suggesting that the deformation mechanism map of hcp-iron resembles those of other hexagonal metals.

  14. Tests of Scintillator+WLS Strips for Muon System at Future Colliders

    SciTech Connect

    Denisov, Dmitri; Evdokimov, Valery; Lukić, Strahinja

    2015-10-11

    Prototype scintilator+WLS strips with SiPM readout for muon system at future colliders were tested for light yield, time resolution and position resolution. Depending on the configuration, light yield of up to 36 photoelectrons per muon per SiPM has been achieved, as well as time resolution of 0.5 ns and position resolution of ~ 7 cm.

  15. Simultaneous measurement of all thermoelectric properties of bulk materials in the temperature range 300-600 K.

    PubMed

    Kolb, H; Dasgupta, T; Zabrocki, K; Mueller, E; de Boor, J

    2015-07-01

    Thermoelectric materials can directly convert heat into electrical energy. The characterization of different materials is an important part in thermoelectric materials research to improve their properties. Usually, different methods and setups are combined for the temperature dependent determination of all thermoelectric key quantities - Seebeck coefficient, electrical conductivity, and thermal conductivity. Here, we present a measurement system for the simultaneous determination of all of these quantities plus the direct determination of the figure of merit by means of the Harman method (zT)H in a temperature range from room temperature up to 600 K. A simultaneous measurement saves time and reduces the measurement error, and the change of all material properties can be monitored even for unstable materials. Thermal conductivity measurements are inherently affected by undesired thermal losses, in particular, through radiation at higher temperatures. We show a simple experimental approach to measure radiation losses and correct for those. Comparative measurements on traditional systems show good agreement for all measured quantities. PMID:26233393

  16. Bayesian WLS/GLS regression for regional skewness analysis for regions with large crest stage gage networks

    USGS Publications Warehouse

    Veilleux, Andrea G.; Stedinger, Jery R.; Eash, David A.

    2012-01-01

    This paper summarizes methodological advances in regional log-space skewness analyses that support flood-frequency analysis with the log Pearson Type III (LP3) distribution. A Bayesian Weighted Least Squares/Generalized Least Squares (B-WLS/B-GLS) methodology that relates observed skewness coefficient estimators to basin characteristics in conjunction with diagnostic statistics represents an extension of the previously developed B-GLS methodology. B-WLS/B-GLS has been shown to be effective in two California studies. B-WLS/B-GLS uses B-WLS to generate stable estimators of model parameters and B-GLS to estimate the precision of those B-WLS regression parameters, as well as the precision of the model. The study described here employs this methodology to develop a regional skewness model for the State of Iowa. To provide cost effective peak-flow data for smaller drainage basins in Iowa, the U.S. Geological Survey operates a large network of crest stage gages (CSGs) that only record flow values above an identified recording threshold (thus producing a censored data record). CSGs are different from continuous-record gages, which record almost all flow values and have been used in previous B-GLS and B-WLS/B-GLS regional skewness studies. The complexity of analyzing a large CSG network is addressed by using the B-WLS/B-GLS framework along with the Expected Moments Algorithm (EMA). Because EMA allows for the censoring of low outliers, as well as the use of estimated interval discharges for missing, censored, and historic data, it complicates the calculations of effective record length (and effective concurrent record length) used to describe the precision of sample estimators because the peak discharges are no longer solely represented by single values. Thus new record length calculations were developed. The regional skewness analysis for the State of Iowa illustrates the value of the new B-WLS/BGLS methodology with these new extensions.

  17. Fiber

    MedlinePlus

    ... it can help with weight control. Fiber aids digestion and helps prevent constipation . It is sometimes used ... fiber attracts water and turns to gel during digestion. This slows digestion. Soluble fiber is found in ...

  18. Field Testing of LIDAR-Assisted Feedforward Control Algorithms for Improved Speed Control and Fatigue Load Reduction on a 600-kW Wind Turbine: Preprint

    SciTech Connect

    Kumar, Avishek A.; Bossanyi, Ervin A.; Scholbrock, Andrew K.; Fleming, Paul; Boquet, Mathieu; Krishnamurthy, Raghu

    2015-12-14

    A severe challenge in controlling wind turbines is ensuring controller performance in the presence of a stochastic and unknown wind field, relying on the response of the turbine to generate control actions. Recent technologies such as LIDAR, allow sensing of the wind field before it reaches the rotor. In this work a field-testing campaign to test LIDAR Assisted Control (LAC) has been undertaken on a 600-kW turbine using a fixed, five-beam LIDAR system. The campaign compared the performance of a baseline controller to four LACs with progressively lower levels of feedback using 35 hours of collected data.

  19. WLS-ENO: Weighted-least-squares based essentially non-oscillatory schemes for finite volume methods on unstructured meshes

    NASA Astrophysics Data System (ADS)

    Liu, Hongxu; Jiao, Xiangmin

    2016-06-01

    ENO (Essentially Non-Oscillatory) and WENO (Weighted Essentially Non-Oscillatory) schemes are widely used high-order schemes for solving partial differential equations (PDEs), especially hyperbolic conservation laws with piecewise smooth solutions. For structured meshes, these techniques can achieve high order accuracy for smooth functions while being non-oscillatory near discontinuities. For unstructured meshes, which are needed for complex geometries, similar schemes are required but they are much more challenging. We propose a new family of non-oscillatory schemes, called WLS-ENO, in the context of solving hyperbolic conservation laws using finite-volume methods over unstructured meshes. WLS-ENO is derived based on Taylor series expansion and solved using a weighted least squares formulation. Unlike other non-oscillatory schemes, the WLS-ENO does not require constructing sub-stencils, and hence it provides a more flexible framework and is less sensitive to mesh quality. We present rigorous analysis of the accuracy and stability of WLS-ENO, and present numerical results in 1-D, 2-D, and 3-D for a number of benchmark problems, and also report some comparisons against WENO.

  20. Raman scattering of 2H-MoS2 at simultaneous high temperature and high pressure (up to 600 K and 18.5 GPa)

    NASA Astrophysics Data System (ADS)

    Jiang, JianJun; Li, HePing; Dai, LiDong; Hu, HaiYing; Zhao, ChaoShuai

    2016-03-01

    The Raman spectroscopy of natural molybdenite powder was investigated at simultaneous conditions of high temperature and high pressure in a heatable diamond anvil cell (DAC), to obtain the temperature and pressure dependence of the main Raman vibrational modes (E1g, E2 g 1 ,A1g, and 2LA(M)). Over our experimental temperature and pressure range (300-600 K and 1 atm-18.5 GPa), the Raman modes follow a systematic blue shift with increasing pressure, and red shift with increasing temperature. The results were calculated by three-variable linear fitting. The mutual correlation index of temperature and pressure indicates that the pressure may reduce the temperature dependence of Raman modes. New Raman bands due to structural changes emerged at about 3-4 GPa lower than seen in previous studies; this may be caused by differences in the pressure hydrostaticity and shear stress in the sample cell that promote the interlayer sliding.

  1. Flow curves of hcp-iron up to 19 GPa and 600 K using a combination of synchrotron radiation and the DDIA

    NASA Astrophysics Data System (ADS)

    Nishiyama, N.; Wang, Y.; Rivers, M. L.; Sutton, S. R.; Cookson, D.

    2006-12-01

    We performed in-situ X-ray diffraction and radiography experiments of hcp-iron up to 19 GPa and 600 K. Deformation experiments were performed at the GSECARS 13-BM-D beamline (APS) using a DDIA with a monochromatic X-ray diffraction and a radiographic imaging system. We used four tungsten carbide and two sintered diamond anvils with truncated edge length of 2 mm. Pressure medium was a mixture of boron and epoxy and a cylindrical graphite furnace was used. The starting material was a fragment of pure bcc-iron wire and two deformation pistons made of alumina were situated above and below the sample. First, the cell assembly was compressed uniformly at room temperature up to about 14 GPa. Then the sample was heated to about 700 K to convert bcc to hcp-iron. After the transformation, several deformation cycles were carried out, yielding five independent stress-strain curves with sample shortening at pressures up to 19 GPa and three different temperatures (600, 400, and 300 K). In all the curves, differential stresses reached saturation at about 3 percent strain, suggesting that deformation reached steady state. The differential stresses at steady state flow were 1.8-2.5 GPa, decreasing with increasing temperature and decreasing strain rate. Using isothermal mechanical data, we determined stress exponents (n) at 600 and 400 K, yielding 7 and 31, respectively. The mechanical data of hcp-iron are consistent with the deformation mechanism map of zinc (Ashby and Frost, 1981), which suggests that, at about 18 GPa, hcp-iron deforms in the Peierls plasticity (low-temperature plasticity) regime at 400 K whereas it deforms in the low-temperature power-law creep regime at 600 K. Thus, deformation mechanisms map of hcp-iron may be similar to those of other hexagonal metals, such as zinc.

  2. Fiber

    MedlinePlus

    ... broccoli, spinach, and artichokes legumes (split peas, soy, lentils, etc.) almonds Look for the fiber content of ... salsa, taco sauce, and cheese for dinner. Add lentils or whole-grain barley to your favorite soups. ...

  3. Fiber

    MedlinePlus

    ... short period of time can cause intestinal gas ( flatulence ), bloating , and abdominal cramps . This problem often goes ... 213. National Research Council. Dietary Reference Intakes for Energy, Carbohydrate, Fiber, Fat, Fatty Acids, Cholesterol, Protein, and ...

  4. A Scintillator tile-fiber preshower detector for the CDF Central Calorimeter

    SciTech Connect

    S. Lami

    2004-08-12

    The front face of the CDF central calorimeter is being equipped with a new Preshower detector, based on scintillator tiles read out by WLS fibers. A light yield of about 40 pe/MIP at the tile exit was obtained, exceeding the design requirements.

  5. Genome-wide detection of CNVs in Chinese indigenous sheep with different types of tails using ovine high-density 600K SNP arrays.

    PubMed

    Zhu, Caiye; Fan, Hongying; Yuan, Zehu; Hu, Shijin; Ma, Xiaomeng; Xuan, Junli; Wang, Hongwei; Zhang, Li; Wei, Caihong; Zhang, Qin; Zhao, Fuping; Du, Lixin

    2016-01-01

    Chinese indigenous sheep can be classified into three types based on tail morphology: fat-tailed, fat-rumped, and thin-tailed sheep, of which the typical breeds are large-tailed Han sheep, Altay sheep, and Tibetan sheep, respectively. To unravel the genetic mechanisms underlying the phenotypic differences among Chinese indigenous sheep with tails of three different types, we used ovine high-density 600K SNP arrays to detect genome-wide copy number variation (CNV). In large-tailed Han sheep, Altay sheep, and Tibetan sheep, 371, 301, and 66 CNV regions (CNVRs) with lengths of 71.35 Mb, 51.65 Mb, and 10.56 Mb, respectively, were identified on autosomal chromosomes. Ten CNVRs were randomly chosen for confirmation, of which eight were successfully validated. The detected CNVRs harboured 3130 genes, including genes associated with fat deposition, such as PPARA, RXRA, KLF11, ADD1, FASN, PPP1CA, PDGFA, and PEX6. Moreover, multilevel bioinformatics analyses of the detected candidate genes were significantly enriched for involvement in fat deposition, GTPase regulator, and peptide receptor activities. This is the first high-resolution sheep CNV map for Chinese indigenous sheep breeds with three types of tails. Our results provide valuable information that will support investigations of genomic structural variation underlying traits of interest in sheep. PMID:27282145

  6. Use of a 600-kHz Acoustic Doppler Current Profiler to measure estuarine bottom type, relative abundance of submerged aquatic vegetation, and eelgrass canopy height

    NASA Astrophysics Data System (ADS)

    Warren, Joseph D.; Peterson, Bradley J.

    2007-03-01

    The acoustic backscatter intensity signal from a high-frequency (600 kHz) Acoustic Doppler Current Profiler (ADCP) was used to categorize four different types of bottom habitat (sand, mud, sparse and dense vegetation) in a shallow-water estuary (Shinnecock Bay, NY, USA). A diver survey of the bay measured sediment and bottom vegetation characteristics at 85 sites within the bay. These data were used to groundtruth the acoustic data. Acoustic data were collected at four sites with known bottom types and used to develop an algorithm that could categorize the bottom type. The slope of the echo intensity profile close to the bottom was used to determine the bottom type and the relative numerical density (sparse or dense) of Submerged Aquatic Vegetation (SAV). In areas where eelgrass ( Zostera marina) was the dominant SAV species, the intensity profile data were analyzed to measure the height of the vegetation canopy. An acoustic survey which categorized the bottom type of the bay was conducted from a small vessel. The percentage of sampled sites categorized as each bottom habitat type from the acoustic survey was similar to those obtained by the diver survey. These methods may provide a means to rapidly survey estuarine habitats and measure spatial and temporal variations in SAV populations, as well as changes in the height of the eelgrass canopy.

  7. Genome-wide detection of CNVs in Chinese indigenous sheep with different types of tails using ovine high-density 600K SNP arrays

    PubMed Central

    Zhu, Caiye; Fan, Hongying; Yuan, Zehu; Hu, Shijin; Ma, Xiaomeng; Xuan, Junli; Wang, Hongwei; Zhang, Li; Wei, Caihong; Zhang, Qin; Zhao, Fuping; Du, Lixin

    2016-01-01

    Chinese indigenous sheep can be classified into three types based on tail morphology: fat-tailed, fat-rumped, and thin-tailed sheep, of which the typical breeds are large-tailed Han sheep, Altay sheep, and Tibetan sheep, respectively. To unravel the genetic mechanisms underlying the phenotypic differences among Chinese indigenous sheep with tails of three different types, we used ovine high-density 600K SNP arrays to detect genome-wide copy number variation (CNV). In large-tailed Han sheep, Altay sheep, and Tibetan sheep, 371, 301, and 66 CNV regions (CNVRs) with lengths of 71.35 Mb, 51.65 Mb, and 10.56 Mb, respectively, were identified on autosomal chromosomes. Ten CNVRs were randomly chosen for confirmation, of which eight were successfully validated. The detected CNVRs harboured 3130 genes, including genes associated with fat deposition, such as PPARA, RXRA, KLF11, ADD1, FASN, PPP1CA, PDGFA, and PEX6. Moreover, multilevel bioinformatics analyses of the detected candidate genes were significantly enriched for involvement in fat deposition, GTPase regulator, and peptide receptor activities. This is the first high-resolution sheep CNV map for Chinese indigenous sheep breeds with three types of tails. Our results provide valuable information that will support investigations of genomic structural variation underlying traits of interest in sheep. PMID:27282145

  8. Ageing studies of wavelength shifter fibers for the TILECAL/ATLAS experiment

    NASA Astrophysics Data System (ADS)

    Silva, J.; Maio, A.; Pina, J.; Santos, J.; Saraiva, J. G.

    2007-09-01

    Natural and accelerated ageing studies for the different components of the TILECAL calorimeter, of the ATLAS experiment, play a central role in forecasting the evolution of the detector's performance throughout its operating life. It is possible that the operation of ATLAS will be extended by 5 years in an upgraded LHC scenario. Such prospect makes these studies even more important, in order to assess the contribution of the natural ageing in relation to the other processes inducing performance loss in the optical components. Among other activities in this LHC/CERN collaboration, the Lisbon calorimetry group is involved in studying the impact of radiation damage and natural ageing in optical characteristics of the TILECAL wavelength shifter (WLS) optical fibers and scintillators, and to reevaluate the light budget of the tile/fiber system. The light yield and the attenuation length of the WLS and scintillating optical fibers are measured using an X- Y table. Results are presented for several sets of WLS optical fibers (Kuraray Y11(200)MSJ) whose characteristics have been monitored since 1999. Most of those 338 fibers are from the mass production for the TILECAL detector: 208 non-aluminized 200 cm fibers, from several production batches, and 128 batch #6 aluminized fibers, with lengths ranging from 114 to 207 cm.

  9. Study of tile/fiber systems manufactured from Kharkov injection molded and Kuraray SCSN-81 scintillators

    NASA Astrophysics Data System (ADS)

    Nemashkalo, A.; Popov, V.; Rubashkin, A.; Sorokin, P.; Zatserklianiy, A.; Borisenko, A.; Senchishin, V.; Skrebtsov, O.; Bolotov, V.

    1998-12-01

    We present the measurements of light output, light yield uniformity, and recovery after radiation damage of the tile/fiber systems made from the Kharkov injection molded and Kuraray SCSN-81 scintillators. The tiles were trapezoidal in shape, 131×90×122 mm3, with a Kuraray Y11 multiclad WLS read-out. The results are compared with those obtained using the tile/fiber systems manufactured from the Kuraray SCSN-81 scintillator and tested under the same conditions.

  10. Histologic and Phenotypic Factors and MC1R Status Associated with BRAF(V600E), BRAF(V600K), and NRAS Mutations in a Community-Based Sample of 414 Cutaneous Melanomas.

    PubMed

    Hacker, Elke; Olsen, Catherine M; Kvaskoff, Marina; Pandeya, Nirmala; Yeo, Abrey; Green, Adèle C; Williamson, Richard M; Triscott, Joe; Wood, Dominic; Mortimore, Rohan; Hayward, Nicholas K; Whiteman, David C

    2016-04-01

    Cutaneous melanomas arise through causal pathways involving interplay between exposure to UV radiation and host factors, resulting in characteristic patterns of driver mutations in BRAF, NRAS, and other genes. To gain clearer insights into the factors contributing to somatic mutation genotypes in melanoma, we collected clinical and epidemiologic data, performed skin examinations, and collected saliva and tumor samples from a community-based series of 414 patients aged 18 to 79, newly diagnosed with cutaneous melanoma. We assessed constitutional DNA for nine common polymorphisms in melanocortin-1 receptor gene (MC1R). Tumor DNA was assessed for somatic mutations in 25 different genes. We observed mutually exclusive mutations in BRAF(V600E) (26%), BRAF(V600K) (8%), BRAF(other) (5%), and NRAS (9%). Compared to patients with BRAF wild-type melanomas, those with BRAF(V600E) mutants were significantly younger, had more nevi but fewer actinic keratoses, were more likely to report a family history of melanoma, and had tumors that were more likely to harbor neval remnants. BRAF(V600K) mutations were also associated with high nevus counts. Both BRAF(V600K) and NRAS mutants were associated with older age but not with high sun exposure. We also found no association between MC1R status and any somatic mutations in this community sample of cutaneous melanomas, contrary to earlier reports. PMID:26807515

  11. Comment on "Measurements of the temperature dependent diffusion coefficient of nanoparticles in the range of 295-600 K at atmospheric pressure" by V. Y. Rudyak, S. N. Dubtsov, and A. M. Baklanov

    SciTech Connect

    Lewis, E.R.

    2010-03-01

    In a recent paper in this journal, Rudyak, Dubtsov, and Baklanov (2009) presented results of measurements of the penetration of nanoparticles with diameters from 3.5 to 84 nm at temperatures from {approx}300 to 600 K through a set of wire screens, from which they inferred diffusion coefficients. They argued that the formulation typically used for C, the Cunningham correction that accounts for non-continuum effects on the diffusion of nanoparticles, is not valid for temperatures greater than {approx}300 K, and they proposed a modification of this formulation which depends on both temperature and particle size. It is shown here that this modification produces unphysical results in that it yields negative values of the momentum accommodation coefficient. A likely reason for their results is that they used a polydisperse size distribution, for which the main contribution to the measured penetration would be from particles at sizes far from those attributed to them.

  12. Monte Carlo code G3sim for simulation of plastic scintillator detectors with wavelength shifter fiber readout

    SciTech Connect

    Mohanty, P. K.; Dugad, S. R.; Gupta, S. K.

    2012-04-15

    A detailed description of a compact Monte Carlo simulation code ''G3sim'' for studying the performance of a plastic scintillator detector with wavelength shifter (WLS) fiber readout is presented. G3sim was developed for optimizing the design of new scintillator detectors used in the GRAPES-3 extensive air shower experiment. Propagation of the blue photons produced by the passage of relativistic charged particles in the scintillator is treated by incorporating the absorption, total internal, and diffuse reflections. Capture of blue photons by the WLS fibers and subsequent re-emission of longer wavelength green photons is appropriately treated. The trapping and propagation of green photons inside the WLS fiber is treated using the laws of optics for meridional and skew rays. Propagation time of each photon is taken into account for the generation of the electrical signal at the photomultiplier. A comparison of the results from G3sim with the performance of a prototype scintillator detector showed an excellent agreement between the simulated and measured properties. The simulation results can be parametrized in terms of exponential functions providing a deeper insight into the functioning of these versatile detectors. G3sim can be used to aid the design and optimize the performance of scintillator detectors prior to actual fabrication that may result in a considerable saving of time, labor, and money spent.

  13. Monte Carlo code G3sim for simulation of plastic scintillator detectors with wavelength shifter fiber readout.

    PubMed

    Mohanty, P K; Dugad, S R; Gupta, S K

    2012-04-01

    A detailed description of a compact Monte Carlo simulation code "G3sim" for studying the performance of a plastic scintillator detector with wavelength shifter (WLS) fiber readout is presented. G3sim was developed for optimizing the design of new scintillator detectors used in the GRAPES-3 extensive air shower experiment. Propagation of the blue photons produced by the passage of relativistic charged particles in the scintillator is treated by incorporating the absorption, total internal, and diffuse reflections. Capture of blue photons by the WLS fibers and subsequent re-emission of longer wavelength green photons is appropriately treated. The trapping and propagation of green photons inside the WLS fiber is treated using the laws of optics for meridional and skew rays. Propagation time of each photon is taken into account for the generation of the electrical signal at the photomultiplier. A comparison of the results from G3sim with the performance of a prototype scintillator detector showed an excellent agreement between the simulated and measured properties. The simulation results can be parametrized in terms of exponential functions providing a deeper insight into the functioning of these versatile detectors. G3sim can be used to aid the design and optimize the performance of scintillator detectors prior to actual fabrication that may result in a considerable saving of time, labor, and money spent. PMID:22559526

  14. Monte Carlo code G3sim for simulation of plastic scintillator detectors with wavelength shifter fiber readout

    NASA Astrophysics Data System (ADS)

    Mohanty, P. K.; Dugad, S. R.; Gupta, S. K.

    2012-04-01

    A detailed description of a compact Monte Carlo simulation code "G3sim" for studying the performance of a plastic scintillator detector with wavelength shifter (WLS) fiber readout is presented. G3sim was developed for optimizing the design of new scintillator detectors used in the GRAPES-3 extensive air shower experiment. Propagation of the blue photons produced by the passage of relativistic charged particles in the scintillator is treated by incorporating the absorption, total internal, and diffuse reflections. Capture of blue photons by the WLS fibers and subsequent re-emission of longer wavelength green photons is appropriately treated. The trapping and propagation of green photons inside the WLS fiber is treated using the laws of optics for meridional and skew rays. Propagation time of each photon is taken into account for the generation of the electrical signal at the photomultiplier. A comparison of the results from G3sim with the performance of a prototype scintillator detector showed an excellent agreement between the simulated and measured properties. The simulation results can be parametrized in terms of exponential functions providing a deeper insight into the functioning of these versatile detectors. G3sim can be used to aid the design and optimize the performance of scintillator detectors prior to actual fabrication that may result in a considerable saving of time, labor, and money spent.

  15. Atmospheric Boundary Layer and Clouds wind speed profile measurements with the new compact long range wind Lidar WindCube(TM) WLS70

    NASA Astrophysics Data System (ADS)

    Boquet, M.; Cariou, J. P.; Sauvage, L.; Lolli, S.; Parmentier, R.; Loaec, S.

    2009-04-01

    To fully understand atmospheric dynamics, climate studies, energy transfer, and weather prediction the wind field is one of the most important atmospheric state variables. Small scales variability and low atmospheric layers are not described with sufficient resolution up to now. To answer these needs, the WLS70 long-range wind Lidar is a new generation of wind Lidars developed by LEOSPHERE, derived from the commercial WindCube™ Lidar widely used by the wind power industry and well-known for its great accuracy and data availability. The WLS70 retrieves the horizontal and vertical wind speed profiles as well as the wind direction at various heights simultaneously inside the boundary layer and cloud layers. The amplitude and spectral content of the backscattering signal are also available. From raw data, the embedded signal processing software performs the computation of the aerosol Doppler shift and backscattering coefficient. Higher values of normalized relative backscattering (NRB) are proportional to higher aerosol concentration. At 1540 nm, molecular scattering being negligible, it is then possible to directly retrieve the Boundary Layer height evolution observing the height at which the WindCube NRB drops drastically. In this work are presented the results of the measurements obtained during the LUAMI campaign that took place in Lindenberg, at the DWD (Deutscher WetterDienst) meteorological observatory, from November 2008 to January 2009. The WLS70 Lidar instrument was placed close together with an EZ Lidar™ ALS450, a rugged and compact eye safe aerosol Lidar that provides a real time measurement of backscattering and extinction coefficients, aerosol optical depth (AOD), automatic detection of the planetary boundary layer (PBL) height and clouds base and top from 100m up to more than 20km. First results put in evidence wind shear and veer phenomena as well as strong convective effects during the raise of the mixing layer or before rain periods. Wind speed

  16. Utilization of wavelength-shifting fibers coupled to ZnS(Ag) and plastic scintillator for simultaneous detection of alpha/beta particles

    NASA Astrophysics Data System (ADS)

    Ifergan, Y.; Dadon, S.; Israelashvili, I.; Osovizky, A.; Gonen, E.; Yehuda-Zada, Y.; Smadja, D.; Knafo, Y.; Ginzburg, D.; Kadmon, Y.; Cohen, Y.; Mazor, T.

    2015-06-01

    Low level radioactive surface contamination measurements require lightweight, large area and high efficiency detector. In most existing scintillation detectors there is a tradeoff between effective area and scintillation light collection. By using wavelength shifting (WLS) fibers the scintillation light may be collected efficiently also in a large area detector. In this study, WLS fibers were coupled to a beta sensitive plastic scintillator layer and to a alpha sensitive silver-activated zinc sulfide ZnS(Ag) layer for detecting both alpha and beta particles. The WLS fibers collect the scintillation light from the whole detector and transfer it to a single PMT. This first prototype unique configuration enables monitoring radioactive contaminated surfaces by both sides of the detector and provides high gamma rejection. In this paper, the detector structure, as well as the detector's measured linear response, will be described. The measured detection efficiency of 238Pu alpha particles (5.5 MeV) is ~63%. The measured detection efficiency for beta particles is ~89% for 90Sr-90Y (average energy of 195.8 keV, 934.8 keV), ~50% for 36Cl (average energy of 251.3 keV), and 35% for 137Cs (average energy of 156.8 keV).

  17. Beam test results for a tungsten-cerium fluoride sampling calorimeter with wavelength-shifting fiber readout

    NASA Astrophysics Data System (ADS)

    Becker, R.; Candelise, V.; Cavallari, F.; Dafinei, I.; Della Ricca, G.; Diemoz, M.; del Re, D.; D'Imperio, G.; Dissertori, G.; Donegà, M.; Dröge, M.; Gelli, S.; Haller, C.; Jorda Lope, C.; Lustermann, W.; Martelli, A.; Meridiani, P.; Micheli, F.; Nessi-Tedaldi, F.; Nuccetelli, M.; Organtini, G.; Quittnat, M.; Pandolfi, F.; Paramatti, R.; Pastrone, N.; Pellegrino, F.; Peruzzi, M.; Rahatlou, S.; Rovelli, C.; Santanastasio, F.; Schönenberger, M.; Soffi, L.; Tabarelli de Fatis, T.; Vazzoler, F.

    2015-07-01

    A sampling calorimeter using cerium fluoride scintillating crystals as active material, interleaved with heavy absorber plates, and read out by wavelength-shifting (WLS) fibers is being studied as a calorimeter option for detectors at the upgraded High-Luminosity LHC (HL-LHC) collider at CERN. A prototype has been exposed to electron beams of different energies at the INFN Frascati (Italy) Beam Test Facility. This paper presents results from the studies performed on the prototype, such as signal amplitudes, light yield and energy resolution.

  18. A scintillating tile/fiber system for the CDF plug upgrade EM calorimeter

    NASA Astrophysics Data System (ADS)

    Aota, S.; Asakawa, T.; Hara, K.; Hayashi, E.; Kim, S.; Kondo, K.; Kuwabara, T.; Miyashita, S.; Nakada, H.; Nakano, I.; Seiya, Y.; Takikawa, K.; Toyoda, H.; Uchida, T.; Yasuoka, K.; Mishina, M.; Iwai, J.; Albrow, M.; Freeman, J.; Limon, P. J.

    1995-01-01

    The plug calorimeter of the Collider Detector at Fermilab (CDF) [1] will be upgraded, replacing the existing gas calorimeter by a scintillating tile/fiber calorimeter. We have completed R&D for the CDF plug upgrade EM calorimeter. We describe the results of the R&D leading to the final design of the tile/fiber system for the calorimeter. Kuraray SCSN38, Kuraray Y11 and PET film (E65) were chosen as materials for scintillating tiles, wavelength shifting (WLS) fibers and a surface reflector on tiles, respectively, in view of obtaining large light yield and uniform response from a tile/fiber system. We decided fiber groove path in a tile, groove cross-sectional shape and groove depth for each tile to get uniform response from a tile/fiber. For the tile/fiber system of the final design, the average light yield was larger than 3.0 photoelectrons per minimum ionizing particle (MIP), the response uniformity in a tile was less than 2.5% and a total cross talk from a tile to the adjacent tiles was less than 2.0%. These results satisfied our requirements.

  19. Dietary Fiber

    MedlinePlus

    Fiber is a substance in plants. Dietary fiber is the kind you eat. It's a type of carbohydrate. You may also see it listed on a food label as soluble fiber or insoluble fiber. Both types have important health benefits. Good sources of dietary fiber include Whole grains Nuts ...

  20. Fiber biology

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Cotton fiber cells arising from seed epidermis is the most important agricultural textile commodity in the world. To produce fully mature fibers, approximately two months of fiber developmental process are required. The timing of four distinctive fiber development stages consisting of initiation, ...

  1. Dietary Fiber

    MedlinePlus

    Fiber is a substance in plants. Dietary fiber is the kind you eat. It's a type of carbohydrate. You may also see it listed on a food label as soluble ... types have important health benefits. Good sources of dietary fiber include Whole grains Nuts and seeds Fruit and ...

  2. Fiber sensing with photorefractive fiber

    NASA Astrophysics Data System (ADS)

    Yu, Francis T. S.; Guo, Ruyan; Wang, Bo; Liu, Yuexin

    2002-11-01

    Optical fibers have been widely used for transmitting temporal signal. However, the transmission of spatial signal has not been fully exploited. Although multimode fiber has a large space-bandwidth product, transmitting spatial signals by using a fiber is rather difficult. When a laser beam is lached into a multimode fiber, the exit light field produces a complicated speckle pattern caused by the modal phasing of the fiber. It is difficult to recover the transmitted informati from the speckle field. However, the fiber speckle field can be used to fiber sensing with a hologrpahic method. In other words, if a hologram is made with the speckle fiber field, the information of the fiber status can be recovered. Thus by reading the hologram by the same speckle field, the reference beam can be reconstructed, which represents the detection of the speckle field. In other words, instead of exploiting the temporal content, the spatial content from a multimode fiber can be exploited for sensing. Our analyses and experimentations have shown that the fiber specklegram sensor (FSS) is highly senstiive to perturbation, and it is less vulnerable to the environment factors. Applications of the FSS to temperature, transversal displacement, and dynamic sensing are also included.

  3. Two Fiber Optical Fiber Thermometry

    NASA Technical Reports Server (NTRS)

    Jones, Mathew R.; Farmer, Jeffery T.; Breeding, Shawn P.

    2000-01-01

    An optical fiber thermometer consists of an optical fiber whose sensing tip is given a metallic coating. The sensing tip of the fiber is essentially an isothermal cavity, so the emission from this cavity will be approximately equal to the emission from a blackbody. Temperature readings are obtained by measuring the spectral radiative heat flux at the end of the fiber at two wavelengths. The ratio of these measurements and Planck's Law are used to infer the temperature at the sensing tip. Optical fiber thermometers have high accuracy, excellent long-term stability and are immune to electromagnetic interference. In addition, they can be operated for extended periods without requiring re-calibration. For these reasons. it is desirable to use optical fiber thermometers in environments such as the International Space Station. However, it has recently been shown that temperature readings are corrupted by emission from the fiber when extended portions of the probe are exposed to elevated temperatures. This paper will describe several ways in which the reading from a second fiber can be used to correct the corrupted temperature measurements. The accuracy and sensitivity to measurement uncertainty will be presented for each method.

  4. Optical Fibers

    NASA Astrophysics Data System (ADS)

    Ghatak, Ajoy; Thyagarajan, K.

    With the development of extremely low-loss optical fibers and their application to communication systems, a revolution has taken fiber glass place during the last 40 years. In 2001, using glass fibers as the transmission medium and lightwaves as carrier wave waves, information was transmitted at a rate more than 1 Tbit/s (which is roughly equivalent to transmission of about 15 million simultaneous telephone conversations) through one hair thin optical fiber. Experimental demonstration of transmission at the rate of 14 Tbit/s over a 160 km long single fiber was demonstrated in 2006, which is equivalent to sending 140 digital high definition movies in 1 s. Very recently record transmission of more than 100 Tbit/s over 165 km single mode fiber has been reported. These can be considered as extremely important technological achievements. In this chapter we will discuss the propagation characteristics of optical fibers with special applications to optical communication systems and also present some of the noncommunication applications such as sensing.

  5. Fireblocking Fibers

    NASA Technical Reports Server (NTRS)

    1986-01-01

    PBI was originally developed for space suits. In 1980, the need for an alternative to asbestos and stricter government anti-pollution standards led to commercialization of the fire blocking fiber. PBI is used for auto racing driver suits and aircraft seat covers. The fiber does not burn in air, is durable and easily maintained. It has been specified by a number of airliners and is manufactured by Hoechst-Celanese Corporation.

  6. Stable high-spectral-flatness mid-infrared supercontinuum generation in Tm-doped fiber amplifier

    NASA Astrophysics Data System (ADS)

    Xue, Guanghui; Zhang, Bin; Yang, Weiqiang; Yin, Ke; Hou, Jing

    2015-08-01

    We demonstrate a stable high-spectral-flatness mid-infrared (mid-IR) supercontinuum (SC) generation in a thulium-doped fiber amplifier (TDFA) with an average output power of 2.32 W in a spectral band of ∼(1875-2700 nm). A 1550 nm distributed feedback (DFB) pulsed laser diode (LD) with repetition rate of 600 kHz and pulse width of 900 ps was used as the seed source. The measured long term stability of SC output power is less than 1.1% rms (root mean square) at the average output power of 2.32 W. The measured slope efficiency from the 793 nm pump power of the TDFA to the total SC output power is ∼14%. The output SC has a 6 dB spectral flatness in the wavelength ranging from 1955 to 2505 nm (550 nm span) at the average output power of 2.32 W.

  7. Photovoltaic fibers

    NASA Astrophysics Data System (ADS)

    Gaudiana, Russell; Eckert, Robert; Cardone, John; Ryan, James; Montello, Alan

    2006-08-01

    It was realized early in the history of Konarka that the ability to produce fibers that generate power from solar energy could be applied to a wide variety of applications where fabrics are utilized currently. These applications include personal items such as jackets, shirts and hats, to architectural uses such as awnings, tents, large covers for cars, trucks and even doomed stadiums, to indoor furnishings such as window blinds, shades and drapes. They may also be used as small fabric patches or fiber bundles for powering or recharging batteries in small sensors. Power generating fabrics for clothing is of particular interest to the military where they would be used in uniforms and body armor where portable power is vital to field operations. In strong sunlight these power generating fabrics could be used as a primary source of energy, or they can be used in either direct sunlight or low light conditions to recharge batteries. Early in 2002, Konarka performed a series of proof-of-concept experiments to demonstrate the feasibility of building a photovoltaic cell using dye-sensitized titania and electrolyte on a metal wire core. The approach taken was based on the sequential coating processes used in making fiber optics, namely, a fiber core, e.g., a metal wire serving as the primary electrode, is passed through a series of vertically aligned coating cups. Each of the cups contains a coating fluid that has a specific function in the photocell. A second wire, used as the counter electrode, is brought into the process prior to entering the final coating cup. The latter contains a photopolymerizable, transparent cladding which hardens when passed through a UV chamber. Upon exiting the UV chamber, the finished PV fiber is spooled. Two hundred of foot lengths of PV fiber have been made using this process. When the fiber is exposed to visible radiation, it generates electrical power. The best efficiency exhibited by these fibers is 6% with an average value in the 4

  8. Fiber crops

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Much research continues to develop renewable, recyclable, sustainable, and bio-based products from agricultural feed stocks such as cotton and flax fiber. Primary requirements are sustainable production, low cost, and consistent and known quality. To better understand these products, research contin...

  9. Fiber distributed feedback laser

    NASA Technical Reports Server (NTRS)

    Elachi, C.; Evans, G. A.; Yeh, C. (Inventor)

    1976-01-01

    Utilizing round optical fibers as communication channels in optical communication networks presents the problem of obtaining a high efficiency coupling between the optical fiber and the laser. A laser is made an integral part of the optical fiber channel by either diffusing active material into the optical fiber or surrounding the optical fiber with the active material. Oscillation within the active medium to produce lasing action is established by grating the optical fiber so that distributed feedback occurs.

  10. Strong fibers

    SciTech Connect

    Li, Che-Yu.

    1991-03-01

    This program was directed to a new and generic approach to the development of new materials with novel and interesting properties, and to the precision fabrication of these materials in one and two-dimensional forms. Advanced deposition processes and microfabrication technology were used to produce fibers and grids of metals, semiconductors, ceramics, and mixtures of controlled composition and structure, and with new and interesting mechanical and physical properties. Deposition processes included electron beam evaporation, co-deposition of mixtures by dual electron beam evaporation, thermal evaporation, sputtering of a single element or compound, sputtering of a single element in a gaseous atmosphere to produce compounds, plasma enhanced chemical vapor deposition (PECVD), low pressure chemical vapor deposition (LPCVD), and selective tungsten chemical vapor deposition (W-CVD). The approach was to use the deposition processes in coordination with patterns generated by optical lithography to produce fibers with transverse dimensions in the micron range, and lengths from less than a millimeter to several centimeters. The approach is also applicable to the production of two-dimensional grids and particulates of controlled sizes and geometries.

  11. Carbon-fiber technology

    NASA Technical Reports Server (NTRS)

    Hansen, C. F.; Parker, J. A.

    1980-01-01

    The state of the art of PAN based carbon fiber manufacture and the science of fiber behavior is surveyed. A review is given of the stabilization by oxidation and the subsequent carbonization of fibers, of the apparent structure of fibers deduced from scanning electron microscopy, from X-ray scattering, and from similarities with soft carbons, and of the known relations between fiber properties and heat treatment temperature. A simplified model is invoked to explain the electrical properties of fibers and recent quantum chemical calculations on atomic clusters are used to elucidate some aspects of fiber conductivity. Some effects of intercalation and oxidative modification of finished fibers are summarized.

  12. Flax Fiber - Interfacial Bonding

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Measured flax fiber physical and chemical properties potentially impact bonding and thus stress transfer between the matrix and fiber within composites. These first attempts at correlating flax fiber quality and biofiber composites contain the initial steps towards identifying key flax fiber charac...

  13. High-fiber foods

    MedlinePlus

    Dietary fiber - self-care ... Dietary fiber adds bulk to your diet. Because it makes you feel full faster, it can help you ... Grains are another important source of dietary fiber. Eat more: ... Whole-grain breads Brown rice Popcorn High-fiber cereals, such ...

  14. Fiber optic temperature sensor

    NASA Technical Reports Server (NTRS)

    Sawatari, Takeo (Inventor); Gaubis, Philip A. (Inventor)

    2000-01-01

    A fiber optic temperature sensor uses a light source which transmits light through an optical fiber to a sensor head at the opposite end of the optical fiber from the light source. The sensor head has a housing coupled to the end of the optical fiber. A metallic reflective surface is coupled to the housing adjacent the end of the optical fiber to form a gap having a predetermined length between the reflective surface and the optical fiber. A detection system is also coupled to the optical fiber which determines the temperature at the sensor head from an interference pattern of light which is reflected from the reflective surface.

  15. Fiber optic temperature sensor

    NASA Technical Reports Server (NTRS)

    Sawatari, Takeo (Inventor); Gaubis, Philip A. (Inventor); Mattes, Brenton L. (Inventor); Charnetski, Clark J. (Inventor)

    1999-01-01

    A fiber optic temperature sensor uses a light source which transmits light through an optical fiber to a sensor head at the opposite end of the optical fiber from the light source. The sensor head has a housing coupled to the end of the optical fiber. A metallic reflective surface is coupled to the housing adjacent the end of the optical fiber to form a gap having a predetermined length between the reflective surface and the optical fiber. A detection system is also coupled to the optical fiber which determines the temperature at the sensor head from an interference pattern of light which is reflected from the reflective surface.

  16. Fiber optic connector

    DOEpatents

    Rajic, S.; Muhs, J.D.

    1996-10-22

    A fiber optic connector and method for connecting composite materials within which optical fibers are imbedded are disclosed. The fiber optic connector includes a capillary tube for receiving optical fibers at opposing ends. The method involves inserting a first optical fiber into the capillary tube and imbedding the unit in the end of a softened composite material. The capillary tube is injected with a coupling medium which subsequently solidifies. The composite material is machined to a desired configuration. An external optical fiber is then inserted into the capillary tube after fluidizing the coupling medium, whereby the optical fibers are coupled. 3 figs.

  17. Fiber optic connector

    DOEpatents

    Rajic, Slobodan; Muhs, Jeffrey D.

    1996-01-01

    A fiber optic connector and method for connecting composite materials within which optical fibers are imbedded. The fiber optic connector includes a capillary tube for receiving optical fibers at opposing ends. The method involves inserting a first optical fiber into the capillary tube and imbedding the unit in the end of a softened composite material. The capillary tube is injected with a coupling medium which subsequently solidifies. The composite material is machined to a desired configuration. An external optical fiber is then inserted into the capillary tube after fluidizing the coupling medium, whereby the optical fibers are coupled.

  18. Coatings for graphite fibers

    NASA Technical Reports Server (NTRS)

    Galasso, F. S.; Scola, D. A.; Veltri, R. D.

    1980-01-01

    Graphite fibers released from composites during burning or an explosion caused shorting of electrical and electronic equipment. Silicon carbide, silica, silicon nitride and boron nitride were coated on graphite fibers to increase their electrical resistances. Resistances as high as three orders of magnitude higher than uncoated fiber were attained without any significant degradation of the substrate fiber. An organo-silicone approach to produce coated fibers with high electrical resistance was also used. Celion 6000 graphite fibers were coated with an organo-silicone compound, followed by hydrolysis and pyrolysis of the coating to a silica-like material. The shear and flexural strengths of composites made from high electrically resistant fibers were considerably lower than the shear and flexural strengths of composites made from the lower electrically resistant fibers. The lower shear strengths of the composites indicated that the coatings on these fibers were weaker than the coating on the fibers which were pyrolyzed at higher temperature.

  19. Alumina fiber strength improvement

    NASA Technical Reports Server (NTRS)

    Pepper, R. T.; Nelson, D. C.

    1982-01-01

    The effective fiber strength of alumina fibers in an aluminum composite was increased to 173,000 psi. A high temperature heat treatment, combined with a glassy carbon surface coating, was used to prevent degradation and improve fiber tensile strength. Attempts to achieve chemical strengthening of the alumina fiber by chromium oxide and boron oxide coatings proved unsuccessful. A major problem encountered on the program was the low and inconsistent strength of the Dupont Fiber FP used for the investigation.

  20. Fiber optic monitoring device

    DOEpatents

    Samborsky, James K.

    1993-01-01

    A device for the purpose of monitoring light transmissions in optical fibers comprises a fiber optic tap that optically diverts a fraction of a transmitted optical signal without disrupting the integrity of the signal. The diverted signal is carried, preferably by the fiber optic tap, to a lens or lens system that disperses the light over a solid angle that facilitates viewing. The dispersed light indicates whether or not the monitored optical fiber or system of optical fibers is currently transmitting optical information.

  1. Specialty optical fibers: revisited

    NASA Astrophysics Data System (ADS)

    Romaniuk, Ryszard S.

    2011-10-01

    The paper contains description of chosen aspects of analysis and design of tailored optical fibers. By specialty optical fibers we understand here the fibers which have complex construction and which serve for the functional processing of optical signal rather than long distance transmission. Thus, they are called also instrumentation optical fibers. The following issues are considered: transmission properties, transformation of optical signal, fiber characteristics, fiber susceptibility to external reactions. The technology of tailored optical fibers offers a wider choice of the design tools for the fiber itself, and then various devices made from these fiber, than classical technology of communication optical fibers. The consequence is different fiber properties, nonstandard dimensions and different metrological problems. The price to be paid for wider design possibilities are bigger optical losses of these fibers and weaker mechanical properties, and worse chemical stability. These fibers find their applications outside the field of telecommunications. The applications of instrumentation optical fibers combine other techniques apart from the photonics ones like: electronic, chemical and mechatronic.

  2. Ceramic fiber reinforced filter

    DOEpatents

    Stinton, David P.; McLaughlin, Jerry C.; Lowden, Richard A.

    1991-01-01

    A filter for removing particulate matter from high temperature flowing fluids, and in particular gases, that is reinforced with ceramic fibers. The filter has a ceramic base fiber material in the form of a fabric, felt, paper of the like, with the refractory fibers thereof coated with a thin layer of a protective and bonding refractory applied by chemical vapor deposition techniques. This coating causes each fiber to be physically joined to adjoining fibers so as to prevent movement of the fibers during use and to increase the strength and toughness of the composite filter. Further, the coating can be selected to minimize any reactions between the constituents of the fluids and the fibers. A description is given of the formation of a composite filter using a felt preform of commercial silicon carbide fibers together with the coating of these fibers with pure silicon carbide. Filter efficiency approaching 100% has been demonstrated with these filters. The fiber base material is alternately made from aluminosilicate fibers, zirconia fibers and alumina fibers. Coating with Al.sub.2 O.sub.3 is also described. Advanced configurations for the composite filter are suggested.

  3. In vivo near-realtime volumetric optical-resolution photoacoustic microscopy using a high-repetition-rate nanosecond fiber-laser

    NASA Astrophysics Data System (ADS)

    Shi, Wei; Hajireza, Parsin; Shao, Peng; Forbrich, Alexander; Zemp, Roger J.

    2011-08-01

    Optical-resolution photoacoustic microscopy (OR-PAM) is capable of achieving optical-absorption-contrast images with micron-scale spatial resolution. Previous OR-PAM systems have been frame-rate limited by mechanical scanning speeds and laser pulse repetition rate (PRR). We demonstrate OR-PAM imaging using a diode-pumped nanosecond-pulsed Ytterbium-doped 532-nm fiber laser with PRR up to 600 kHz. Combined with fast-scanning mirrors, our proposed system provides C-scan and 3D images with acquisition frame rate of 4 frames per second (fps) or higher, two orders of magnitude faster than previously published systems. High-contrast images of capillary-scale microvasculature in a live Swiss Webster mouse ear with ~6-μm optical lateral spatial resolution are demonstrated.

  4. Fiber optics in adverse environments

    SciTech Connect

    Lyous, P.B.

    1982-01-01

    Radiation effects in optical fibers are considered, taking into account recent progress in the investigation of radiation resistant optical fibers, radiation damage in optical fibers, radiation-induced transient absorption in optical fibers, X-ray-induced transient attenuation at low temperatures in polymer clad silica (PCS) fibers, optical fiber composition and radiation hardness, the response of irradiated optical waveguides at low temperatures, and the effect of ionizing radiation on fiber-optic waveguides. Other topics explored are related to environmental effects on components of fiber optic systems, and radiation detection systems using optical fibers. Fiber optic systems in adverse environments are also discussed, giving attention to the survivability of Army fiber optics systems, space application of fiber optics systems, fiber optic wavelength multiplexing for civil aviation applications, a new fiber optic data bus topology, fiber optics for aircraft engine/inlet control, and application of fiber optics in high voltage substations.

  5. Fiber Optics Technology.

    ERIC Educational Resources Information Center

    Burns, William E.

    1986-01-01

    Discusses various applications of fiber optics technology: information systems, industrial robots, medicine, television, transportation, and training. Types of jobs that will be available with fiber optics training (such as electricians and telephone cable installers and splicers) are examined. (CT)

  6. Fiber optic chemical sensors

    NASA Astrophysics Data System (ADS)

    Jung, Chuck C.; McCrae, David A.; Saaski, Elric W.

    1998-09-01

    This paper provides a broad overview of the field of fiber optic chemical sensors. Several different types of fiber optic sensors and probes are described, and references are cited for each category discussed.

  7. Fiber Optics Instrumentation Development

    NASA Technical Reports Server (NTRS)

    Chan, Patrick Hon Man; Parker, Allen R., Jr.; Richards, W. Lance

    2010-01-01

    This is a general presentation of fiber optics instrumentation development work being conducted at NASA Dryden for the past 10 years and recent achievements in the field of fiber optics strain sensors.

  8. Omnidirectional fiber optic tiltmeter

    DOEpatents

    Benjamin, B.C.; Miller, H.M.

    1983-06-30

    A tiltmeter is provided which is useful in detecting very small movements such as earth tides. The device comprises a single optical fiber, and an associated weight affixed thereto, suspended from a support to form a pendulum. A light source, e.g., a light emitting diode, mounted on the support transmits light through the optical fiber to a group of further optical fibers located adjacent to but spaced from the free end of the single optical fiber so that displacement of the single optical fiber with respect to the group will result in a change in the amount of light received by the individual optical fibers of the group. Photodetectors individually connectd to the fibers produce corresponding electrical outputs which are differentially compared and processed to produce a resultant continuous analog output representative of the amount and direction of displacement of the single optical fiber.

  9. Soluble vs. insoluble fiber

    MedlinePlus

    ... diseases. Soluble fiber attracts water and turns to gel during digestion. This slows digestion. Soluble fiber is found in oat bran, barley, nuts, seeds, beans, lentils, peas, and some fruits and vegetables. It is also found in psyllium, ...

  10. Soluble vs. insoluble fiber

    MedlinePlus

    ... soluble and insoluble. Both are important for health, digestion, and preventing diseases. Soluble fiber attracts water and turns to gel during digestion. This slows digestion. Soluble fiber is found in ...

  11. Fiber pulling apparatus modification

    NASA Technical Reports Server (NTRS)

    Smith, Guy A.; Workman, Gary L.

    1992-01-01

    A reduced gravity fiber pulling apparatus (FPA) was constructed in order to study the effects of gravity on glass fiber formation. The apparatus was specifically designed and built for use on NASA's KC-135 aircraft. Four flights have been completed to date during which E-glass fiber was successfully produced in simulated zero, high, and lunar gravity environments. In addition simulated lunar soil samples were tested for their fiber producing properties using the FPA.

  12. Helical Fiber Amplifier

    DOEpatents

    Koplow, Jeffrey P.; Kliner, Dahy; Goldberg, Lew

    2002-12-17

    A multi-mode gain fiber is provided which affords substantial improvements in the maximum pulse energy, peak power handling capabilities, average output power, and/or pumping efficiency of fiber amplifier and laser sources while maintaining good beam quality (comparable to that of a conventional single-mode fiber source). These benefits are realized by coiling the multimode gain fiber to induce significant bend loss for all but the lowest-order mode(s).

  13. Fiber optic coupled optical sensor

    DOEpatents

    Fleming, Kevin J.

    2001-01-01

    A displacement sensor includes a first optical fiber for radiating light to a target, and a second optical fiber for receiving light from the target. The end of the first fiber is adjacent and not axially aligned with the second fiber end. A lens focuses light from the first fiber onto the target and light from the target onto the second fiber.

  14. The Fiber Optic Connection.

    ERIC Educational Resources Information Center

    Reese, Susan

    2003-01-01

    Describes the fiber optics programs at the Career and Technical Center in Berlin, Pennsylvania and the Charles S. Monroe Technology Center in Loudoun County, Virginia. Discusses the involvement of the Fiber Optic Association with education, research and development, manufacturing, sales, distribution, installation, and maintenance of fiber optic…

  15. Advanced Engineering Fibers.

    ERIC Educational Resources Information Center

    Edie, Dan D.; Dunham, Michael G.

    1987-01-01

    Describes Clemson University's Advanced Engineered Fibers Laboratory, which was established to provide national leadership and expertise in developing the processing equipment and advance fibers necessary for the chemical, fiber, and textile industries to enter the composite materials market. Discusses some of the laboratory's activities in…

  16. Oxynitride glass fibers

    NASA Technical Reports Server (NTRS)

    Patel, Parimal J.; Messier, Donald R.; Rich, R. E.

    1991-01-01

    Research at the Army Materials Technology Laboratory (AMTL) and elsewhere has shown that many glass properties including elastic modulus, hardness, and corrosion resistance are improved markedly by the substitution of nitrogen for oxygen in the glass structure. Oxynitride glasses, therefore, offer exciting opportunities for making high modulus, high strength fibers. Processes for making oxynitride glasses and fibers of glass compositions similar to commercial oxide glasses, but with considerable enhanced properties, are discussed. We have made glasses with elastic moduli as high as 140 GPa and fibers with moduli of 120 GPa and tensile strengths up to 2900 MPa. AMTL holds a U.S. patent on oxynitride glass fibers, and this presentation discusses a unique process for drawing small diameter oxynitride glass fibers at high drawing rates. Fibers are drawn through a nozzle from molten glass in a molybdenum crucible at 1550 C. The crucible is situated in a furnace chamber in flowing nitrogen, and the fiber is wound in air outside of the chamber, making the process straightforward and commercially feasible. Strengths were considerably improved by improving glass quality to minimize internal defects. Though the fiber strengths were comparable with oxide fibers, work is currently in progress to further improve the elastic modulus and strength of fibers. The high elastic modulus of oxynitride glasses indicate their potential for making fibers with tensile strengths surpassing any oxide glass fibers, and we hope to realize that potential in the near future.

  17. Linearly polarized fiber amplifier

    DOEpatents

    Kliner, Dahv A.; Koplow, Jeffery P.

    2004-11-30

    Optically pumped rare-earth-doped polarizing fibers exhibit significantly higher gain for one linear polarization state than for the orthogonal state. Such a fiber can be used to construct a single-polarization fiber laser, amplifier, or amplified-spontaneous-emission (ASE) source without the need for additional optical components to obtain stable, linearly polarized operation.

  18. Mineral Fiber Toxicology

    EPA Science Inventory

    The chemical and physical properties of different forms of mineral fibers impact biopersistence and pathology in the lung. Fiber chemistry, length, aspect ratio, surface area and dose are critical factors determining mineral fiber-associated health effects including cancer and as...

  19. Multimaterial Acoustic Fibers

    NASA Astrophysics Data System (ADS)

    Chocat, Noemie

    The emergence of multimaterial fibers that combine a multiplicity of solid materials with disparate electrical, optical, and mechanical properties into a single fiber presents new opportunities for extending fiber applications well beyond optical transmission. Fiber reflectors, thermal detectors, photodetectors, chemical sensors, surface-emitting fiber lasers, fiber diodes, and other functional fiber devices have been demonstrated with this approach. Yet, throughout this development and indeed the development of fibers in general, a key premise has remained unchanged : that fibers are essentially static devices incapable of controllably changing their properties at high frequencies. Unique opportunities would arise if a rapid, electrically-driven mechanism for changing fiber properties existed. A wide spectrum of hitherto passive fiber devices could at once become active with applications spanning electronics, mechanics, acoustics, and optics, with the benefits of large surface-area, structural robustness, and mechanical flexibility. This thesis addresses the challenges and opportunities associated with the realization of electromechanical transduction in fibers through the integration of internal piezoelectric and electrostrictive domains. The fundamental challenges related to the fabrication of piezoelectric devices in fiber form are analyzed from a materials perspective, and candidate materials and geometries are selected that are compatible with the thermal drawing process. The first realization of a thermally drawn piezoelectric fiber device is reported and its piezoelectric response is established over a wide range of frequencies. The acoustic properties of piezoelectric fiber devices are characterized and related to their mechanical and geometric properties. Collective effects in multi-fiber constructs are discussed and demonstrated by the realization of a linear phased array of piezoelectric fibers capable of acoustic beam steering. High strain actuation

  20. Hybrid matrix fiber composites

    DOEpatents

    Deteresa, Steven J.; Lyon, Richard E.; Groves, Scott E.

    2003-07-15

    Hybrid matrix fiber composites having enhanced compressive performance as well as enhanced stiffness, toughness and durability suitable for compression-critical applications. The methods for producing the fiber composites using matrix hybridization. The hybrid matrix fiber composites include two chemically or physically bonded matrix materials, whereas the first matrix materials are used to impregnate multi-filament fibers formed into ribbons and the second matrix material is placed around and between the fiber ribbons that are impregnated with the first matrix material and both matrix materials are cured and solidified.

  1. Fiber optic monitoring device

    DOEpatents

    Samborsky, J.K.

    1993-10-05

    A device for the purpose of monitoring light transmissions in optical fibers comprises a fiber optic tap that optically diverts a fraction of a transmitted optical signal without disrupting the integrity of the signal. The diverted signal is carried, preferably by the fiber optic tap, to a lens or lens system that disperses the light over a solid angle that facilitates viewing. The dispersed light indicates whether or not the monitored optical fiber or system of optical fibers is currently transmitting optical information. 4 figures.

  2. Fiber optic sensors

    NASA Technical Reports Server (NTRS)

    Hesse, J.; Sohler, W.

    1984-01-01

    A survey of the developments in the field of fiber optics sensor technology is presented along with a discussion of the advantages of optical measuring instruments as compared with electronic sensors. The two primary types of fiber optics sensors, specifically those with multiwave fibers and those with monowave fibers, are described. Examples of each major sensor type are presented and discussed. Multiwave detectors include external and internal fiber optics sensors. Among the monowave detectors are Mach-Zender interferometers, Michelson interferometers, Sagnac interferometers (optical gyroscopes), waveguide resonators, and polarimeter sensors. Integrated optical sensors and their application in spectroscopy are briefly discussed.

  3. Fiber coating method

    DOEpatents

    Corman, Gregory Scot

    2001-01-01

    A coating is applied to reinforcing fibers arranged into a tow by coaxially aligning the tow with an adjacent separation layer and winding or wrapping the tow and separation layer onto a support structure in an interleaved manner so that the separation layer separates a wrap of the tow from an adjacent wrap of the tow. A coating can then be uniformly applied to the reinforcing fibers without defects caused by fiber tow to fiber tow contact. The separation layer can be a carbon fiber veil.

  4. Fiber coating method

    DOEpatents

    Corman, Gregory Scot

    2003-04-15

    A coating is applied to reinforcing fibers arranged into a tow by coaxially aligning the tow with an adjacent separation layer and winding or wrapping the tow and separation layer onto a support structure in an interleaved manner so that the separation layer separates a wrap of the tow from an adjacent wrap of the tow. A coating can then be uniformly applied to the reinforcing fibers without defects caused by fiber tow to fiber tow contact. The separation layer can be a carbon fiber veil.

  5. Fiber optic laser rod

    DOEpatents

    Erickson, G.F.

    1988-04-13

    A laser rod is formed from a plurality of optical fibers, each forming an individual laser. Synchronization of the individual fiber lasers is obtained by evanescent wave coupling between adjacent optical fiber cores. The fiber cores are dye-doped and spaced at a distance appropriate for evanescent wave coupling at the wavelength of the selected dye. An interstitial material having an index of refraction lower than that of the fiber core provides the optical isolation for effective lasing action while maintaining the cores at the appropriate coupling distance. 2 figs.

  6. Fiber optic monitoring device

    SciTech Connect

    Samborsky, J.K.

    1992-12-31

    This invention is comprised of a device for the purpose of monitoring light transmissions in optical fibers comprises a fiber optic tap that optically diverts a fraction of a transmitted optical signal without disrupting the integrity of the signal. The diverted signal is carried, preferably by the fiber optic tap, to a lens or lens system that disperses the light over a solid angle that facilitates viewing. The dispersed light indicates whether or not the monitored optical fiber or system of optical fibers is currently transmitting optical information.

  7. Kinetics of fiber solidification

    PubMed Central

    Mercader, C.; Lucas, A.; Derré, A.; Zakri, C.; Moisan, S.; Maugey, M.; Poulin, P.

    2010-01-01

    Many synthetic or natural fibers are produced via the transformation of a liquid solution into a solid filament, which allows the wet processing of high molecular weight polymers, proteins, or inorganic particles. Synthetic wet-spun fibers are used in our everyday life from clothing to composite reinforcement applications. Spun fibers are also common in nature. Silk solidification results from the coagulation of protein solutions. The chemical phenomena involved in the formation of all these classes of fibers can be quite different but they all share the same fundamental transformation from a liquid to a solid state. The solidification process is critical because it governs the production rate and the strength that fibers can sustain to be drawn and wound. An approach is proposed in this work to investigate the kinetics of fiber solidification. This approach consists in circulating solidifying fibers in the extensional flow of a surrounding liquid. Such as polymers in extensional flows, the fibers break if resultant drag forces exceed the fiber tensile strength. The solidification kinetics of nanotube composite fibers serves as a validation example of this approach. The method could be extended to other systems and advance thereby the science and technology of fiber and textile materials. It is also a way to directly visualize the scission of chain-like systems in extensional flows. PMID:20937910

  8. Kinetics of fiber solidification.

    PubMed

    Mercader, C; Lucas, A; Derré, A; Zakri, C; Moisan, S; Maugey, M; Poulin, P

    2010-10-26

    Many synthetic or natural fibers are produced via the transformation of a liquid solution into a solid filament, which allows the wet processing of high molecular weight polymers, proteins, or inorganic particles. Synthetic wet-spun fibers are used in our everyday life from clothing to composite reinforcement applications. Spun fibers are also common in nature. Silk solidification results from the coagulation of protein solutions. The chemical phenomena involved in the formation of all these classes of fibers can be quite different but they all share the same fundamental transformation from a liquid to a solid state. The solidification process is critical because it governs the production rate and the strength that fibers can sustain to be drawn and wound. An approach is proposed in this work to investigate the kinetics of fiber solidification. This approach consists in circulating solidifying fibers in the extensional flow of a surrounding liquid. Such as polymers in extensional flows, the fibers break if resultant drag forces exceed the fiber tensile strength. The solidification kinetics of nanotube composite fibers serves as a validation example of this approach. The method could be extended to other systems and advance thereby the science and technology of fiber and textile materials. It is also a way to directly visualize the scission of chain-like systems in extensional flows. PMID:20937910

  9. Fiber optic vibration sensor

    DOEpatents

    Dooley, J.B.; Muhs, J.D.; Tobin, K.W.

    1995-01-10

    A fiber optic vibration sensor utilizes two single mode optical fibers supported by a housing with one optical fiber fixedly secured to the housing and providing a reference signal and the other optical fiber having a free span length subject to vibrational displacement thereof with respect to the housing and the first optical fiber for providing a signal indicative of a measurement of any perturbation of the sensor. Damping or tailoring of the sensor to be responsive to selected levels of perturbation is provided by altering the diameter of optical fibers or by immersing at least a portion of the free span length of the vibration sensing optical fiber into a liquid of a selected viscosity. 2 figures.

  10. Fiber optic vibration sensor

    DOEpatents

    Dooley, Joseph B.; Muhs, Jeffrey D.; Tobin, Kenneth W.

    1995-01-01

    A fiber optic vibration sensor utilizes two single mode optical fibers supported by a housing with one optical fiber fixedly secured to the housing and providing a reference signal and the other optical fiber having a free span length subject to vibrational displacement thereof with respect to the housing and the first optical fiber for providing a signal indicative of a measurement of any perturbation of the sensor. Damping or tailoring of the sensor to be responsive to selected levels of perturbation is provided by altering the diameter of optical fibers or by immersing at least a portion of the free span length of the vibration sensing optical fiber into a liquid of a selected viscosity.

  11. Fiber Accelerating Structures

    SciTech Connect

    Hammond, Andrew P.; /Reed Coll. /SLAC

    2010-08-25

    One of the options for future particle accelerators are photonic band gap (PBG) fiber accelerators. PBG fibers are specially designed optical fibers that use lasers to excite an electric field that is used to accelerate electrons. To improve PBG accelerators, the basic parameters of the fiber were tested to maximize defect size and acceleration. Using the program CUDOS, several accelerating modes were found that maximized these parameters for several wavelengths. The design of multiple defects, similar to having closely bound fibers, was studied to find possible coupling or the change of modes. The amount of coupling was found to be dependent on distance separated. For certain distances accelerating coupled modes were found and examined. In addition, several non-periodic fiber structures were examined using CUDOS. The non-periodic fibers produced several interesting results and promised more modes given time to study them in more detail.

  12. Fiber draw synthesis

    PubMed Central

    Orf, Nicholas D.; Shapira, Ofer; Sorin, Fabien; Danto, Sylvain; Baldo, Marc A.; Joannopoulos, John D.; Fink, Yoel

    2011-01-01

    The synthesis of a high-melting temperature semiconductor in a low-temperature fiber drawing process is demonstrated, substantially expanding the set of materials that can be incorporated into fibers. Reagents in the solid state are arranged in proximate domains within a fiber preform. The preform is fluidized at elevated temperatures and drawn into fiber, reducing the lateral dimensions and bringing the domains into intimate contact to enable chemical reaction. A polymer preform containing a thin layer of selenium contacted by tin–zinc wires is drawn to yield electrically contacted crystalline ZnSe domains of sub-100-nm scales. The in situ synthesized compound semiconductor becomes the basis for an electronic heterostructure diode of arbitrary length in the fiber. The ability to synthesize materials within fibers while precisely controlling their geometry and electrical connectivity at submicron scales presents new opportunities for increasing the complexity and functionality of fiber structures.

  13. Indium fluoride glass fibers

    NASA Astrophysics Data System (ADS)

    Saad, Mohammed

    2012-03-01

    Fluoride glasses are the only material that transmit light from ultraviolet to mid-infrared and can be drawn into industrial optical fibers. The mechanical and optical properties of new indium fluoride glass fibers have been investigated. Multimode fiber 190 microns, has very high mechanical strength greater than 100 kpsi and optical loss as low as 45 dB/km between 2 and 4 microns. Unlike chalcogenide glass fibers, indium fluoride fiber has a wide transmission window from 0.3 to 5.5 microns without any absorption peak. Indium fluoride glass fibers are the technology of choice for all application requiring transmission up to 5 micron such as infrared contour measure (IRCM) and chemical sensing. Furthermore, Indium fluoride glasses have low phonon energy and can be heavily doped and co-doped whit rare-earth elements. Therefore they are very promising candidates for infrared fiber lasers.

  14. Tapered fiber amplifier

    NASA Astrophysics Data System (ADS)

    Russell, Stephen D.; Stamnitz, Timothy C.

    1990-07-01

    A tapered optical fiber amplifier is designed to provide for long-distance, un-repeatered fiber optic communications. Two single-mode fiber portions are tapered to efficiently intensify and couple an information signal from a laser diode and a pump signal at a shorter wavelength into a fused, tapered single-mode fiber optic coupler. The concentrated information signal and concentrated pump signal are combined via the coupler which is coupled to a several-kilometer length of a relatively small core diametered single-mode fiber to create nonlinear optical effect (stimulated Raman scattering) (SRS). The SRS causes Raman shift of the pump light into the small core diametered single-mode fiber length, thereby generating SRS to result in a signal amplification and an efficient extraction of the amplified signal via the tapered output fiber portion or pigtail.

  15. Fiber optic moisture sensor

    DOEpatents

    Kirkham, R.R.

    1984-08-03

    A method and apparatus for sensing moisture changes by utilizing optical fiber technology. One embodiment uses a reflective target at the end of an optical fiber. The reflectance of the target varies with its moisture content and can be detected by a remote unit at the opposite end of the fiber. A second embodiment utilizes changes in light loss along the fiber length. This can be attributed to changes in reflectance of cladding material as a function of its moisture content. It can also be affected by holes or inserts interposed in the cladding material and/or fiber. Changing light levels can also be coupled from one fiber to another in an assembly of fibers as a function of varying moisture content in their overlapping lengths of cladding material.

  16. Coatings for Graphite Fibers

    NASA Technical Reports Server (NTRS)

    Galasso, F. S.; Scola, D. A.; Veltri, R. D.

    1980-01-01

    Several approaches for applying high resistance coatings continuously to graphite yarn were investigated. Two of the most promising approaches involved (1) chemically vapor depositing (CVD) SiC coatings on the surface of the fiber followed by oxidation, and (2) drawing the graphite yarn through an organo-silicone solution followed by heat treatments. In both methods, coated fibers were obtained which exhibited increased electrical resistances over untreated fibers and which were not degraded. This work was conducted in a previous program. In this program, the continuous CVD SiC coating process used on HTS fiber was extended to the coating of HMS, Celion 6000, Celion 12000 and T-300 graphite fiber. Electrical resistances three order of magnitude greater than the uncoated fiber were measured with no significant degradation of the fiber strength. Graphite fibers coated with CVD Si3N4 and BN had resistances greater than 10(exp 6) ohm/cm. Lower pyrolysis temperatures were used in preparing the silica-like coatings also resulting in resistances as high as three orders of magnitude higher than the uncoated fiber. The epoxy matrix composites prepared using these coated fibers had low shear strengths indicating that the coatings were weak.

  17. Fiber optic temperature sensor

    NASA Technical Reports Server (NTRS)

    Morey, W. W.; Glenn, W. H.; Snitzer, E.

    1983-01-01

    A temperature sensor has been developed that utilizes the temperature dependent absorption of a rare earth doped optical fiber. The temperature measurement is localized at a remote position by splicing a short section of the rare earth fiber into a loop of commercial data communication fiber that sends and returns an optical probe signal to the temperature sensitive section of fiber. The optical probe signal is generated from two different wavelength filtered LED sources. A four port fiber optic coupler combines the two separate wavelength signals into the fiber sensing loop. Time multiplexing is used so that each signal wavelength is present at a different time. A reference signal level measurement is also made from the LED sources and a ratio taken with the sensor signal to produce a transmission measurement of the fiber loop. The transmission is affected differently at each wavelength by the rare earth temperature sensitive fiber. The temperature is determined from a ratio of the two transmission measurements. This method eliminates any ambiguity with respect to changes in signal level in the fiber loop such as mating and unmating optical connectors. The temperature range of the sensor is limited to about 800 C by the temperature limit fo the feed fibers.

  18. Fiber optic micro accelerometer

    DOEpatents

    Swierkowski, Steve P.

    2005-07-26

    An accelerometer includes a wafer, a proof mass integrated into the wafer, at least one spring member connected to the proof mass, and an optical fiber. A Fabry-Perot cavity is formed by a partially reflective surface on the proof mass and a partially reflective surface on the end of the optical fiber. The two partially reflective surfaces are used to detect movement of the proof mass through the optical fiber, using an optical detection system.

  19. Fiber composite flywheel rim

    DOEpatents

    Davis, D.E.; Ingham, K.T.

    1987-04-28

    A flywheel comprising a hub having at least one radially projecting disc, an annular rim secured to said disc and providing a surface circumferential to said hub, a first plurality of resin-impregnated fibers wound about said rim congruent to said surface, and a shell enclosing said first plurality of fibers and formed by a second plurality of resin-impregnated fibers wound about said rim tangentially to said surface. 2 figs.

  20. Fiber composite flywheel rim

    DOEpatents

    Davis, Donald E.; Ingham, Kenneth T.

    1987-01-01

    A flywheel 2 comprising a hub 4 having at least one radially projecting disc 6, an annular rim 14 secured to said disc and providing a surface circumferential to said hub, a first plurality of resin-impregnated fibers 22 wound about said rim congruent to said surface, and a shell 26 enclosing said first plurality of fibers and formed by a second plurality of resin-impregnated fibers wound about said rim tangentially to said surface.

  1. Continuous Fiber Ceramic Composites

    SciTech Connect

    2002-09-01

    Fiber-reinforced ceramic composites demonstrate the high-temperature stability of ceramics--with an increased fracture toughness resulting from the fiber reinforcement of the composite. The material optimization performed under the continuous fiber ceramic composites (CFCC) included a series of systematic optimizations. The overall goals were to define the processing window, to increase the robustinous of the process, to increase process yield while reducing costs, and to define the complexity of parts that could be fabricated.

  2. Fiber optic choline biosensor

    NASA Astrophysics Data System (ADS)

    Wang, Hong; Cao, Xiaojian; Jia, Ke; Chai, Xueting; Lu, Hua; Lu, Zuhong

    2001-10-01

    A fiber optic fluorescence biosensor for choline is introduced in this paper. Choline is an important neurotransmitter in mammals. Due to the growing needs for on-site clinical monitoring of the choline, much effect has been devoted to develop choline biosensors. Fiber-optic fluorescence biosensors have many advantages, including miniaturization, flexibility, and lack of electrical contact and interference. The choline fiber-optic biosensor we designed implemented a bifurcated fiber to perform fluorescence measurements. The light of the blue LED is coupled into one end of the fiber as excitation and the emission spectrum from sensing film is monitored by fiber-spectrometer (S2000, Ocean Optics) through the other end of the fiber. The sensing end of the fiber is coated with Nafion film dispersed with choline oxidase and oxygen sensitive luminescent Ru(II) complex (Tris(2,2'-bipyridyl)dichlororuthenium(II), hexahydrate). Choline oxidase catalyzes the oxidation of choline to betaine and hydrogen peroxide while consuming oxygen. The fluorescence intensity of oxygen- sensitive Ru(II) are related to the choline concentration. The response of the fiber-optic sensor in choline solution is represented and discussed. The result indicates a low-cost, high-performance, portable choline biosensor.

  3. ZBLAN, Silica Fiber Comparison

    NASA Technical Reports Server (NTRS)

    1998-01-01

    This graph depicts the increased signal quality possible with optical fibers made from ZBLAN, a family of heavy-metal fluoride glasses (fluorine combined zirconium, barium, lanthanum, aluminum, and sodium) as compared to silica fibers. NASA is conducting research on pulling ZBLAN fibers in the low-g environment of space to prevent crystallization that limits ZBLAN's usefulness in optical fiber-based communications. In the graph, a line closer to the black theoretical maximum line is better. Photo credit: NASA/Marshall Space Flight Center

  4. Splicing Efficiently Couples Optical Fibers

    NASA Technical Reports Server (NTRS)

    Lutes, G. F.

    1985-01-01

    Method of splicing single-mode optical fibers results in very low transmission losses through joined fiber ends. Coupling losses between joined optical-fiber ends only 0.1 dB. Method needs no special operator training.

  5. Hermetically coated specialty optical fibers

    NASA Astrophysics Data System (ADS)

    Semjonov, Sergey L.; Bogatyrev, Vladimir A.; Malinin, Alexei A.

    2010-10-01

    Manufacturing processes for different types of hermetically coated fibers are described. Optical and mechanical properties of metal and carbon coated fibers are compared. Prospects of application of both types of hermetically coated fibers in special applications are discussed.

  6. Ultrafine PBI fibers and yarns

    NASA Technical Reports Server (NTRS)

    Leal, J. R.; Tan, M.

    1979-01-01

    Gentle precisely controlled process is used to draw polybenzimidazole (PBI) fibers to denier as low as 0.17 per fiber. Yarns of lightweight fibers could be useful in applications where lightweight textiles must withstand high temperatures, corrosion, or radiation.

  7. Soluble and insoluble fiber (image)

    MedlinePlus

    Dietary fiber is the part of food that is not affected by the digestive process in the body. ... of the stool. There are two types of dietary fiber, soluble and insoluble. Soluble fiber retains water and ...

  8. 76 FR 58029 - Agency Information Collection Activities: Form N-600K, Extension of a Currently Approved...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-09-19

    ... collection was previously published in the Federal Register on June 29, 2011, at 76 FR 38197, allowing for a... under Section 322. The Department of Homeland Security, U.S. Citizenship and Immigration Services (USCIS.../Collection: Application for Citizenship and Issuance of Certificate under Section 322. ] (3) Agency...

  9. 76 FR 38197 - Agency Information Collection Activities; Form N-600K, Revision of a Currently Approved...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-06-29

    ... under section 322. OMB Control No. 1615-0087. The Department of Homeland Security, U.S. Citizenship and...) Title of the Form/Collection: Application for Citizenship and Issuance of Certificate under Section 322... citizenship under section 322 of the Immigration and Nationality Act. (5) An estimate of the total number...

  10. ROLE OF FIBER MODIFICATION IN NATURAL FIBER COMPOSITE PROCESSING

    SciTech Connect

    Fifield, Leonard S.; Denslow, Kayte M.; Gutowska, Anna; Simmons, Kevin L.; Holbery, Jim

    2005-11-03

    The prediction and characterization of the adhesion between fiber, surface treatment, and polymer is critical to the success of large-scale natural fiber based polymer composites in automotive semi-structural application. The two primary factors limiting the use of natural fiber in polymer composites are fiber moisture uptake and fiber degradation during high-temperature processing. In this study, we have developed several fiber surface modification techniques and analyzed the fiber-polymer adhesion of modified fibers to more clearly understand the critical parameters controlling moisture uptake, swelling, and fiber degradation due to interfacial structure. We will present a overview of surface modification techniques we have applied to date for hemp fiber sources, and illustrate a path to characterize surface modification effects on natural fiber adhesion in thermoplastic composites.

  11. FLAX FIBER IN TEXTILES

    Technology Transfer Automated Retrieval System (TEKTRAN)

    REFINED, SHORT STAPLE FLAX FIBER CAN BE BLENDED WITH COTTON AND SPUN ON DRY SYSTEMS THAT ARE PREVALENT IN THE U.S. RESEARCH IS REQUIRED TO OPTIMIZE THE FIBER PROPERTIES AND THE PROCESSING SYSTEMS TO MORE EFFICIENTLY BLEND FLAX WITH COTTON. INCLUSION OF FLAX WITH COTTON PROVIDES YARN AND FABRIC PROPE...

  12. MEGARA fiber bundles

    NASA Astrophysics Data System (ADS)

    Pérez-Calpena, A.; García-Vargas, María. Luisa; Arrillaga, X.; Gil de Paz, A.; Sánchez-Blanco, E.; Martínez-Delgado, I.; Carrera, M. A.; Gallego, J.; Carrasco, E.; Sánchez-Moreno, F. M.; Iglesias-Páramo, J.

    2014-07-01

    MEGARA (Multi Espectrógrafo en GTC de Alta Resolución para Astronomía) is the future optical Integral-Field Unit (IFU) and Multi-Object Spectrograph (MOS) for the 10.4-m Gran Telescopio CANARIAS (GTC). MEGARA has three different fiber bundles, the Large Central Bundle covering 12.5 arcsec x 11.3 arcsec on sky, the Small Compact Bundle, of 8.5 arcsec x 6.7 arcsec, and a Fiber MOS positioner system that is able to place up to 100 mini-bundles with 7 fibers each in MOS configuration within a 3.5 arcmin x 3.5 arcmin FOV. The MEGARA focal plane subsystems are located at one of the GTC Folded Cassegrain focal stations. A field lens provides a telecentric focal plane, where the fibers are located. Micro-lenses arrays couple the telescope beam to the collimator focal ratio at the entrance of the fibers. Finally, the fibers, organized in bundles conducted the light from the focal plane to the pseudo-slit plates at the entrance of the MEGARA spectrograph, which shall be located at one of the Nasmyth platforms. This article also summarizes the prototypes already done and describes the set-up that shall be used to integrate fibers and micro-lens and characterize the fiber bundles.

  13. Fiber Sensor Technology Today

    NASA Astrophysics Data System (ADS)

    Hotate, Kazuo

    2006-08-01

    Fiber sensor technologies are overviewed. Since the early 1970s, this field has been developed, on the basis of the same devices and photonic principles as fiber communication technologies. Besides simple configurations, in which the fiber acts only as a data transmission line, sophisticated configurations have also been developed, in which the fiber is used as a device to realize unique sensing mechanisms. The fiber optic gyroscope (FOG) is a good example, and has been developed as an absolute rotation sensor used, for example, for navigation and/or attitude control applications. Compared with traditional spinning-mass gyroscopes, the FOG has advantages, such as a short warming-up time, a light weight, and easy handling. A Japanese satellite, which was launched in August 2005 with a mission to observe the aurora, is controlled with a FOG. The FOG has also been used in consumer applications, such as the camera stabilizer, radio-controlled (RC) helicopter navigation, and the control of humanoid robots. Recently, distributed and multiplexed sensing schemes, in particular, have been studied and developed, in which a long fiber acts like a “nerve” for feeling the strain and/or the temperature distribution along the fiber. Performances of artificial nerve systems have markedly improved within the last couple of years, in spatial resolution and measurement speed. By embedding the “fiber-optic nerve system” in aircraft wings, bridges and tall buildings, these materials and structures can sense damage to prevent disasters.

  14. Super capacitor with fibers

    SciTech Connect

    Farmer, Joseph Collin; Kaschmitter, James

    2015-02-17

    An electrical cell apparatus includes a first current collector made of a multiplicity of fibers, a second current collector spaced from the first current collector; and a separator disposed between the first current collector and the second current collector. The fibers are contained in a foam.

  15. Low dielectric polyimide fibers

    NASA Technical Reports Server (NTRS)

    Dorogy, William E., Jr. (Inventor); St.clair, Anne K. (Inventor)

    1994-01-01

    A high temperature resistant polyimide fiber that has a dielectric constant of less than 3 is presented. The fiber was prepared by first reacting 2,2-bis (4-(4aminophenoxy)phenyl) hexafluoropropane with 2,2-bis (3,4-dicarboxyphenyl) hexafluoropropane dianhydride in an aprotic solvent to form a polyamic acid resin solution. The polyamic acid resin solution is then extruded into a coagulation medium to form polyamic acid fibers. The fibers are thermally cured to their polyimide form. Alternatively, 2,2-bis(4-(4-aminophenoxy)phenyl) hexafluoropropane is reacted with 2,2-bis(3,4-dicarboxyphenyl) hexafluoropropane dianhydride to form a polyamic acid, and the polyamic acid is chemically converted to its polyimide form. The polyimide is then dissolved in a solvent to form a polyimide resin solution, and the polyimide resin is extruded into a coagulation medium to form a polyimide wet gel filament. In order to obtain polyimide fibers of increased tensile properties, the polyimide wet gel filaments are stretched at elevated temperatures. The tensile properties of the fibers were measured and found to be in the range of standard textile fibers. Polyimide fibers obtained by either method will have a dielectric constant similar to that of the corresponding polymer, viz., less than 3 at 10 GHz.

  16. Diamond fiber field emitters

    DOEpatents

    Blanchet-Fincher, Graciela B.; Coates, Don M.; Devlin, David J.; Eaton, David F.; Silzars, Aris K.; Valone, Steven M.

    1996-01-01

    A field emission electron emitter comprising an electrode formed of at least one diamond, diamond-like carbon or glassy carbon composite fiber, said composite fiber having a non-diamond core and a diamond, diamond-like carbon or glassy carbon coating on said non-diamond core, and electronic devices employing such a field emission electron emitter.

  17. Infrared optical fibers

    NASA Astrophysics Data System (ADS)

    Drexhage, Martin G.; Moynihan, Cornelius T.

    1988-11-01

    The development of IR optical fibers for medical, laser, industrial, and telecommunications applications is discussed. IR studies of single and polycrystalline materials, chalcogenide glasses, and heavy-metal fluoride glasses are reviewed. It is suggested that heavy-metal fluoride glasses are the best prospects for obtaining optical losses lower than those in high-quality silica fibers.

  18. Multimode optical fiber

    DOEpatents

    Bigot-Astruc, Marianne; Molin, Denis; Sillard, Pierre

    2014-11-04

    A depressed graded-index multimode optical fiber includes a central core, an inner depressed cladding, a depressed trench, an outer depressed cladding, and an outer cladding. The central core has an alpha-index profile. The depressed claddings limit the impact of leaky modes on optical-fiber performance characteristics (e.g., bandwidth, core size, and/or numerical aperture).

  19. Ion-exchange hollow fibers

    NASA Technical Reports Server (NTRS)

    Rembaum, A.; Yen, S. P. S.; Klein, E. (Inventor)

    1976-01-01

    An ion-exchange hollow fiber is prepared by introducing into the wall of the fiber polymerizable liquid monomers, and polymerizing the monomers therein to form solid, insoluble, crosslinked, ion-exchange resin particles which embed in the wall of the fiber. Excess particles blocking the central passage or bore of the fiber are removed by forcing liquid through the fiber. The fibers have high ion-exchange capacity, a practical wall permeability and good mechanical strength even with very thin wall dimensions. Experimental investigation of bundles of ion-exchange hollow fibers attached to a header assembly have shown the fiber to be very efficient in removing counterions from solution.

  20. Ion-exchange hollow fibers

    NASA Technical Reports Server (NTRS)

    Rembaum, Alan (Inventor); Yen, Shiao-Ping S. (Inventor); Klein, Elias (Inventor)

    1980-01-01

    An ion-exchange hollow fiber is prepared by introducing into the wall of the fiber polymerizable liquid monomers, and polymerizing the monomers therein to form solid, insoluble, cross-linked, ion-exchange resin particles which embed in the wall of the fiber. Excess particles blocking the central passage or bore of the fiber are removed by forcing liquid through the fiber. The fibers have high ion-exchange capacity, a practical wall permeability and good mechanical strength even with very thin wall dimensions. Experimental investigation of bundles of ion-exchange hollow fibers attached to a header assembly have shown the fiber to be very efficient in removing counterions from solution.

  1. Ion-exchange hollow fibers

    NASA Technical Reports Server (NTRS)

    Rembaum, Alan (Inventor); Yen, Shiao-Ping S. (Inventor); Klein, Elias (Inventor)

    1977-01-01

    An ion-exchange hollow fiber is prepared by introducing into the wall of the fiber polymerizable liquid monomers, and polymerizing the monomers therein to form solid, insoluble, cross-linked, ion-exchange resin particles which embed in the wall of the fiber. Excess particles blocking the central passage or bore of the fiber are removed by forcing liquid through the fiber. The fibers have high ion-exchange capacity, a practical wall permeability and good mechanical strength even with very thin wall dimensions. Experimental investigation of bundles of ion-exchange hollow fibers attached to a header assembly have shown the fiber to be very efficient in removing counterions from solution.

  2. Fiber optic attenuator

    NASA Technical Reports Server (NTRS)

    Buzzetti, Mike F. (Inventor)

    1994-01-01

    A fiber optic attenuator of the invention is a mandrel structure through which a bundle of optical fibers is wrapped around in a complete circle. The mandrel structure includes a flexible cylindrical sheath through which the bundle passes. A set screw on the mandrel structure impacts one side of the sheath against two posts on the opposite side of the sheath. By rotating the screw, the sheath is deformed to extend partially between the two posts, bending the fiber optic bundle to a small radius controlled by rotating the set screw. Bending the fiber optic bundle to a small radius causes light in each optical fiber to be lost in the cladding, the amount depending upon the radius about which the bundle is bent.

  3. Python fiber optic seal

    SciTech Connect

    Ystesund, K.; Bartberger, J.; Brusseau, C.; Fleming, P.; Insch, K.; Tolk, K.

    1993-08-01

    Sandia National Laboratories has developed a high security fiber optic seal that incorporates tamper resistance features that are not available in commercial fiber optic seals. The Python Seal is a passive fiber optic loop seal designed to give indication of unauthorized entry. The seal includes a fingerprint feature that provides seal identity information in addition to the unique fiber optic pattern created when the seal is installed. The fiber optic cable used for the seal loop is produced with tamper resistant features that increase the difficulty of attacking that component of a seal. A Seal Reader has been developed that will record the seal signature and the fingerprint feature of the seal. A Correlator software program then compares seal images to establish a match or mismatch. SNL is also developing a Polaroid reader to permit hard copies of the seal patterns to be obtained directly from the seal.

  4. Fluorescent fiber diagnostics

    DOEpatents

    Toeppen, John S.

    1994-10-04

    A fluorescent fiber (13) having a doped core (16) is pumped (11) by light (18) of a relatively short wavelength to produce fluorescence at a longer wavelength that is detected by detector (24). The level of fluorescence is monitored (26) and evaluated to provide information as to the excitation of the fiber (13) or the environment thereof. In particular, the level of intensity of the detected fluorescence may be used to measure the intensity of a light beam (18) passing axially through an optical fiber system (12) (FIG. 1 ), or the intensity of a light beam (46) passing radially through a fluorescent fiber (13) (FIG. 2 ), or the level of a fluid (32) in a tank (31) (FIG. 3 ), or a scintillation event (37) in a fluorescent fiber (13) pumped to produce amplification of the scintillation event (FIG. 4 ).

  5. Fluorescent fiber diagnostics

    DOEpatents

    Toeppen, John S.

    1994-01-01

    A fluorescent fiber (13) having a doped core (16) is pumped (11) by light (18) of a relatively short wavelength to produce fluorescence at a longer wavelength that is detected by detector (24). The level of fluorescence is monitored (26) and evaluated to provide information as to the excitation of the fiber (13) or the environment thereof. In particular, the level of intensity of the detected fluorescence may be used to measure the intensity of a light beam (18) passing axially through an optical fiber system (12) (FIG. 1 ), or the intensity of a light beam (46) passing radially through a fluorescent fiber (13) (FIG. 2 ), or the level of a fluid (32) in a tank (31) (FIG. 3 ), or a scintillation event (37) in a fluorescent fiber (13) pumped to produce amplification of the scintillation event (FIG. 4 ).

  6. Fiber optic hydrophone

    DOEpatents

    Kuzmenko, Paul J.; Davis, Donald T.

    1994-01-01

    A miniature fiber optic hydrophone based on the principles of a Fabry-Perot interferometer. The hydrophone, in one embodiment, includes a body having a shaped flexible bladder at one end which defines a volume containing air or suitable gas, and including a membrane disposed adjacent a vent. An optic fiber extends into the body with one end terminating in spaced relation to the membrane. Acoustic waves in the water that impinge on the bladder cause the pressure of the volume therein to vary causing the membrane to deflect and modulate the reflectivity of the Fabry-Perot cavity formed by the membrane surface and the cleaved end of the optical fiber disposed adjacent to the membrane. When the light is transmitted down the optical fiber, the reflected signal is amplitude modulated by the incident acoustic wave. Another embodiment utilizes a fluid filled volume within which the fiber optic extends.

  7. Fiber optic hydrophone

    DOEpatents

    Kuzmenko, P.J.; Davis, D.T.

    1994-05-10

    A miniature fiber optic hydrophone based on the principles of a Fabry-Perot interferometer is disclosed. The hydrophone, in one embodiment, includes a body having a shaped flexible bladder at one end which defines a volume containing air or suitable gas, and including a membrane disposed adjacent a vent. An optical fiber extends into the body with one end terminating in spaced relation to the membrane. Acoustic waves in the water that impinge on the bladder cause the pressure of the volume therein to vary causing the membrane to deflect and modulate the reflectivity of the Fabry-Perot cavity formed by the membrane surface and the cleaved end of the optical fiber disposed adjacent to the membrane. When the light is transmitted down the optical fiber, the reflected signal is amplitude modulated by the incident acoustic wave. Another embodiment utilizes a fluid filled volume within which the fiber optic extends. 2 figures.

  8. Method for the preparation of carbon fiber from polyolefin fiber precursor, and carbon fibers made thereby

    SciTech Connect

    Naskar, Amit Kumar; Hunt, Marcus Andrew; Saito, Tomonori

    2015-08-04

    Methods for the preparation of carbon fiber from polyolefin fiber precursor, wherein the polyolefin fiber precursor is partially sulfonated and then carbonized to produce carbon fiber. Methods for producing hollow carbon fibers, wherein the hollow core is circular- or complex-shaped, are also described. Methods for producing carbon fibers possessing a circular- or complex-shaped outer surface, which may be solid or hollow, are also described.

  9. Fiber Pulling Apparatus

    NASA Technical Reports Server (NTRS)

    Workman, Gary L.; Smith, Guy A.; OBrien, Sue; Adcock, Leonard

    1998-01-01

    The fiber optics industry has grown into a multi-billion marketplace that will continue to grow into the 21st century. Optical fiber communications is currently dominated by silica glass technology. Successful efforts to improve upon the low loss transmission characteristics of silica fibers have propelled the technology into the forefront of the communications industry. However, reaching the theoretical transmission capability of silica fiber through improved processing has still left a few application areas in which other fiber systems can provide an influential role due to specific characteristics of high theoretical transmission in the 2 - 3 micron wavelength region. One of the other major materials used for optical fibers is the systems based upon Heavy Metal Fluoride Glass (HMFG). Commercial interest is driven primarily by the potential for low loss repeaterless infrared fibers. An example of the major communications marketplace which would benefit from the long distance repeaterless capability of infrared fibers is the submarine cables which link the continents. When considering commercial interests, optical fiber systems provide a healthy industrial position which continues to expand. Major investments in the systems used for optical fiber communications have continued to increase each year and are predicted to continue well into the next century. Estimates of 8.5% compounded annually are predicted through 1999 for the North American market and 1 1 % worldwide. The growth for the optical fiber cable itself is expected to continue between 44 and 50 per cent of the optical fiber communications budget through 1999. The total budget in 1999 world-wide is expected to be in the neighborhood of $9 billion. Another survey predicts that long haul telecommunications represents 15% of a world-wide fiber optics market in 1998. The actual amount allotted to cable was not specified. However, another market research had predicted that the cable costs alone represents more

  10. Fiber optic hydrogen sensor

    DOEpatents

    Buchanan, B.R.; Prather, W.S.

    1991-01-01

    Apparatus and method for detecting a chemical substance by exposing an optic fiber having a core and a cladding to the chemical substance so that the chemical substance can be adsorbed onto the surface of the cladding. The optic fiber is coiled inside a container having a pair of valves for controlling the entrance and exit of the substance. Light from a light source is received by one end of the optic fiber, preferably external to the container, and carried by the core of the fiber. Adsorbed substance changes the transmissivity of the fiber as measured by a spectrophotometer at the other end, also preferably external to the container. Hydrogen is detected by the absorption of infrared light carried by an optic fiber with a silica cladding. Since the adsorption is reversible, a sensor according to the present invention can be used repeatedly. Multiple positions in a process system can be monitored using a single container that can be connected to each location to be monitored so that a sample can be obtained for measurement, or, alternatively, containers can be placed near each position and the optic fibers carrying the partially-absorbed light can be multiplexed for rapid sequential reading, by a single spectrophotometer.

  11. Fiber optic hydrogen sensor

    DOEpatents

    Buchanan, B.R.; Prather, W.S.

    1992-10-06

    An apparatus and method are described for detecting a chemical substance by exposing an optic fiber having a core and a cladding to the chemical substance so that the chemical substance can be adsorbed onto the surface of the cladding. The optic fiber is coiled inside a container having a pair of valves for controlling the entrance and exit of the substance. Light from a light source is received by one end of the optic fiber, preferably external to the container, and carried by the core of the fiber. Adsorbed substance changes the transmissivity of the fiber as measured by a spectrophotometer at the other end, also preferably external to the container. Hydrogen is detected by the absorption of infrared light carried by an optic fiber with a silica cladding. Since the adsorption is reversible, a sensor according to the present invention can be used repeatedly. Multiple positions in a process system can be monitored using a single container that can be connected to each location to be monitored so that a sample can be obtained for measurement, or, alternatively, containers can be placed near each position and the optic fibers carrying the partially-absorbed light can be multiplexed for rapid sequential reading by a single spectrophotometer. 4 figs.

  12. Fiber optic hydrogen sensor

    DOEpatents

    Buchanan, Bruce R.; Prather, William S.

    1992-01-01

    An apparatus and method for detecting a chemical substance by exposing an optic fiber having a core and a cladding to the chemical substance so that the chemical substance can be adsorbed onto the surface of the cladding. The optic fiber is coiled inside a container having a pair of valves for controlling the entrance and exit of the substance. Light from a light source is received by one end of the optic fiber, preferably external to the container, and carried by the core of the fiber. Adsorbed substance changes the transmissivity of the fiber as measured by a spectrophotometer at the other end, also preferably external to the container. Hydrogen is detected by the absorption of infrared light carried by an optic fiber with a silica cladding. Since the adsorption is reversible, a sensor according to the present invention can be used repeatedly. Multiple positions in a process system can be monitored using a single container that can be connected to each location to be monitored so that a sample can be obtained for measurement, or, alternatively, containers can be placed near each position and the optic fibers carrying the partially-absorbed light can be multiplexed for rapid sequential reading by a single spectrophotometer.

  13. Fiber enhanced Raman spectroscopy

    NASA Astrophysics Data System (ADS)

    Frosch, T.; Yan, D.; Hanf, S.; Popp, J.

    2014-05-01

    Fiber enhanced Raman sensing is presented for versatile and extremely sensitive analysis of pharmaceutical drugs and biogenic gases. Elaborated micro-structured optical fibers guide the light with very low losses within their hollow core and provide at the same time a miniaturized sample container for the analytes. Thus, fiber enhanced Raman spectroscopy (FERS) allows for chemically selective detection of minimal sample amounts with high sensitivity. Two examples are presented in this contribution: (i) the detection of picomolar concentrations of pharmaceutical drugs; and (ii) the analysis of biogenic gases within a complex mixture of gases with analytical sensitivities in the ppm range.

  14. Nanotube composite carbon fibers

    NASA Astrophysics Data System (ADS)

    Andrews, R.; Jacques, D.; Rao, A. M.; Rantell, T.; Derbyshire, F.; Chen, Y.; Chen, J.; Haddon, R. C.

    1999-08-01

    Single walled carbon nanotubes (SWNTs) were dispersed in isotropic petroleum pitch matrices to form nanotube composite carbon fibers with enhanced mechanical and electrical properties. We find that the tensile strength, modulus, and electrical conductivity of a pitch composite fiber with 5 wt % loading of purified SWNTs are enhanced by ˜90%, ˜150%, and 340% respectively, as compared to the corresponding values in unmodified isotropic pitch fibers. These results serve to highlight the potential that exits for developing a spectrum of material properties through the selection of the matrix, nanotube dispersion, alignment, and interfacial bonding.

  15. Fiber optic communication links

    SciTech Connect

    Meyer, R. H.

    1980-01-01

    Fiber optics is a new, emerging technology which offers relief from many of the problems which limited past communications links. Its inherent noise immunity and high bandwidth open the door for new designs with greater capabilities. Being a new technology, certain problems can be encountered in specifying and installing a fiber optic link. A general fiber optic system is discussed with emphasis on the advantages and disadvantages. It is not intended to be technical in nature, but a general discussion. Finally, a general purpose prototype Sandia communications link is presented.

  16. QUARTZ FIBER ELECTROSCOPES

    DOEpatents

    Henderson, R.P.

    1957-09-17

    An instrument carried unobtrusively about the person such as in a finger ring to indicate when that person has been exposed to an unusual radiation hazard is described. A metallized quartz fiber is electrically charged to indicate a full scale reading on an etched glass background. The quartz fiber and the scale may be viewed through a magnifying lens for ease of reading. Incident radiation will ionize gaseous particles in the sealed structure thereby allowing the charge to leak off the quartz fiber with its resulting movement across the scale proportionally indicating the radiation exposure.

  17. Muscle Fiber Types and Training.

    ERIC Educational Resources Information Center

    Karp, Jason R.

    2001-01-01

    The specific types of fibers that make up individual muscles greatly influence how people will adapt to their training programs. This paper explains the complexities of skeletal muscles, focusing on types of muscle fibers (slow-twitch and fast-twitch), recruitment of muscle fibers to perform a motor task, and determining fiber type. Implications…

  18. Fiber-Reinforced Composite Foam

    Technology Transfer Automated Retrieval System (TEKTRAN)

    A two-phase method for making fiber-reinforced compositions was developed to achieve uniform fiber dispersion in a composite matrix. The first phase involved mixing together water, fibers, and a portion of a fiber dispersant to form a viscous composition. The high viscosity imparted by the dispersa...

  19. Carbon Fiber Risk Analysis. [conference

    NASA Technical Reports Server (NTRS)

    1979-01-01

    The scope and status of the effort to assess the risks associated with the accidental release of carbon/graphite fibers from civil aircraft is presented. Vulnerability of electrical and electronic equipment to carbon fibers, dispersal of carbon fibers, effectiveness of filtering systems, impact of fiber induced failures, and risk methodology are among the topics covered.

  20. Fiber optics: A research paper

    NASA Technical Reports Server (NTRS)

    Drone, Melinda M.

    1987-01-01

    Some basic aspects concerning fiber optics are examined. Some history leading up to the development of optical fibers which are now used in the transmission of data in many areas of the world is discussed. Basic theory of the operation of fiber optics is discussed along with methods for improving performance of the optical fiber through much research and design. Splices and connectors are compared and short haul and long haul fiber optic networks are discussed. Fiber optics plays many roles in the commercial world. The use of fiber optics for communication applications is emphasized.

  1. Fiber bundle phase conjugate mirror

    SciTech Connect

    Ward, Benjamin G.

    2012-05-01

    An improved method and apparatus for passively conjugating the phases of a distorted wavefronts resulting from optical phase mismatch between elements of a fiber laser array are disclosed. A method for passively conjugating a distorted wavefront comprises the steps of: multiplexing a plurality of probe fibers and a bundle pump fiber in a fiber bundle array; passing the multiplexed output from the fiber bundle array through a collimating lens and into one portion of a non-linear medium; passing the output from a pump collection fiber through a focusing lens and into another portion of the non-linear medium so that the output from the pump collection fiber mixes with the multiplexed output from the fiber bundle; adjusting one or more degrees of freedom of one or more of the fiber bundle array, the collimating lens, the focusing lens, the non-linear medium, or the pump collection fiber to produce a standing wave in the non-linear medium.

  2. Fiber Optics: No Illusion.

    ERIC Educational Resources Information Center

    American School and University, 1983

    1983-01-01

    A campus computer center at Hofstra University (New York) that holds 70 terminals for student use was first a gymnasium, then a language laboratory. Strands of fiber optics are used for the necessary wiring. (MLF)

  3. Hollow-Fiber Clinostat

    NASA Technical Reports Server (NTRS)

    Rhodes, Percy H.; Miller, Teresa Y.; Snyder, Robert S.

    1990-01-01

    Hollow-fiber clinostat, is bioreactor used to study growth and other behavior of cells in simulated microgravity. Cells under study contained in porous hollow fiber immersed in culture medium inside vessel. Bores in hollow fiber allow exchange of gases, nutrients, and metabolic waste products between living cells and external culture media. Hollow fiber lies on axis of vessel, rotated by motor equipped with torque and speed controls. Desired temperature maintained by operating clinostat in standard tissue-culture incubator. Axis of rotation made horizontal or vertical. Designed for use with conventional methods of sterilization and sanitation to prevent contamination of specimen. Also designed for asepsis in assembly, injection of specimen, and exchange of medium.

  4. Fiber and Your Child

    MedlinePlus

    ... pears green peas legumes (dried beans, split peas, lentils, etc.) artichokes almonds A high-fiber food has ... salsa, taco sauce, and cheese for dinner. Add lentils or whole-grain barley to soups. Create mini- ...

  5. Fiber-Scanned Microdisplays

    NASA Technical Reports Server (NTRS)

    Crossman-Bosworth, Janet; Seibel, Eric

    2010-01-01

    Helmet- and head-mounted display systems, denoted fiber-scanned microdisplays, have been proposed to provide information in an "augmented reality" format (meaning that the information would be optically overlaid on the user's field of view).

  6. Cerenkov fiber sampling calorimeters

    SciTech Connect

    Arrington, K.; Kefford, D.; Kennedy, J.; Pisani, R.; Sanzeni, C.; Segall, K.; Wall, D.; Winn, D.R. ); Carey, R.; Dye, S.; Miller, J.; Sulak, L.; Worstell, W. ); Efremenko, Y.; Kamyshkov, Y.; Savin, A.; Shmakov, K.; Tarkovsky, E. )

    1994-08-01

    Clear optical fibers were used as a Cerenkov sampling media in Pb (electromagnetic) and Cu (hadron) absorbers in spaghetti calorimeters, for high rate and high radiation dose experiments, such as the forward region of high energy colliders. The fiber axes were aligned close to the direction of the incident particles (1[degree]--7[degree]). The 7 [lambda] deep hadron tower contained 2.8% by volume 1.5 mm diameter core clear plastic fibers. The 27 radiation length deep electromagnetic towers had packing fractions of 6.8% and 7.2% of 1 mm diameter core quartz fibers as the active Cerenkov sampling medium. The energy resolution on electrons and pions, energy response, pulse shapes and angular studies are presented.

  7. High-fiber foods

    MedlinePlus

    ... potatoes with skin Broccoli, artichokes, squashes, and string beans Vegetable smoothies You can also get more fiber by eating: Legumes, such as lentils, black beans, split peas, kidney beans, lima beans, and chickpeas ...

  8. Fiber optic data transmission

    NASA Technical Reports Server (NTRS)

    Shreve, Steven T.

    1987-01-01

    The Ohio University Avionics Engineering Center is currently developing a fiber optic data bus transmission and reception system that could eventually replace copper cable connections in airplanes. The original form of the system will transmit information from an encoder to a transponder via a fiber optic cable. An altimeter and an altitude display are connected to a fiber optic transmitter by copper cable. The transmitter converts the altimetry data from nine bit parallel to serial form and send these data through a fiber optic cable to a receiver. The receiver converts the data using a cable similar to that used between the altimeter and display. The transmitting and receiving ends also include a display readout. After completion and ground testing of the data bus, the system will be tested in an airborne environment.

  9. Ways to Boost Fiber

    MedlinePlus

    ... and Reproduction Top Articles dad holding baby at apple orchard - Kidney Disease: High- and Moderate-Potassium Foods ... lower its fiber content. For example, one medium apple with the peel contains 4.4 grams of ...

  10. Carbon Fibers and Composites

    NASA Technical Reports Server (NTRS)

    Pride, R. A.

    1979-01-01

    The basic nature of composite materials is considered. Carbon fiber composites and their area of current and planned application in civil aircraft are discussed, specifically within the framework of the various aspects of risk analysis.

  11. Fiber optic gas sensor

    NASA Technical Reports Server (NTRS)

    Chen, Peng (Inventor); Buric, Michael P. (Inventor); Swinehart, Philip R. (Inventor); Maklad, Mokhtar S. (Inventor)

    2010-01-01

    A gas sensor includes an in-fiber resonant wavelength device provided in a fiber core at a first location. The fiber propagates a sensing light and a power light. A layer of a material is attached to the fiber at the first location. The material is able to absorb the gas at a temperature dependent gas absorption rate. The power light is used to heat the material and increases the gas absorption rate, thereby increasing sensor performance, especially at low temperatures. Further, a method is described of flash heating the gas sensor to absorb more of the gas, allowing the sensor to cool, thereby locking in the gas content of the sensor material, and taking the difference between the starting and ending resonant wavelengths as an indication of the concentration of the gas in the ambient atmosphere.

  12. ZBLAN Fiber Comparison

    NASA Technical Reports Server (NTRS)

    1998-01-01

    Sections of ZBLAN fibers pulled in a conventional 1-g process (left) and in experiments aboard NASA's KC-135 low-gravity aircraft. The rough surface of the 1-g fiber indicates surface defects that would scatter an optical signal and greatly degrade its quality. ZBLAN is part of the family of heavy-metal fluoride glasses (fluorine combined zirconium, barium, lanthanum, aluminum, and sodium). NASA is conducting research on pulling ZBLAN fibers in the low-g environment of space to prevent crystallization that limits ZBLAN's usefulness in optical fiber-based communications. ZBLAN is a heavy-metal fluoride glass that shows exceptional promise for high-throughput communications with infrared lasers. Photo credit: NASA/Marshall Space Flight Center

  13. Simulating Optical Fibers.

    ERIC Educational Resources Information Center

    Edgar, Dale

    1988-01-01

    Described is a demonstration of Snell's law using a laser beam and an optical fiber. Provided are the set-up method of the demonstration apparatus and some practical suggestions including "index matching" technique using vaseline. (YP)

  14. Fiber alignment apparatus and method

    DOEpatents

    Kravitz, Stanley H.; Warren, Mial Evans; Snipes, Jr., Morris Burton; Armendariz, Marcelino Guadalupe; Word, V., James Cole

    1997-01-01

    A fiber alignment apparatus includes a micro-machined nickel spring that captures and locks arrays of single mode fibers into position. The design consists of a movable nickel leaf shaped spring and a fixed pocket where fibers are held. The fiber is slid between the spring and a fixed block, which tensions the spring. When the fiber reaches the pocket, it automatically falls into the pocket and is held by the pressure of the leaf spring.

  15. Fiber alignment apparatus and method

    DOEpatents

    Kravitz, S.H.; Warren, M.E.; Snipes, M.B. Jr.; Armendariz, M.G.; Word, J.C. V

    1997-08-19

    A fiber alignment apparatus includes a micro-machined nickel spring that captures and locks arrays of single mode fibers into position. The design consists of a movable nickel leaf shaped spring and a fixed pocket where fibers are held. The fiber is slid between the spring and a fixed block, which tensions the spring. When the fiber reaches the pocket, it automatically falls into the pocket and is held by the pressure of the leaf spring. 8 figs.

  16. Fiber implantation for pattern baldness.

    PubMed

    Hanke, C W; Bergfeld, W F

    1979-01-12

    Examination of 20 patients who had fiber implantation for the treatment of pattern baldness showed that nearly all the fibers had fallen out by ten weeks. Complications observed were facial swelling, infection, foreign-body granulomas, scarring, and permanent hair loss. Scanning electron microscopy identified the fibers as modacrylic fibers. The complications, high monetary cost, and ultimate futility of fiber implantation make it an unacceptable procedure. PMID:364078

  17. [Carbohydrates and fiber].

    PubMed

    Lajolo, F M; de Menezes, E W; Filisetti-Cozzi, T M

    1988-09-01

    Dietary carbohydrates comprise two fractions that may be classified as digestible, and which are useful as energy sources (simple and complex carbohydrates) and fiber, which is presumed to be of no use to the human body. There are insufficient epidemiologic data on the metabolic effects of simple carbohydrates and it is not advisable to make quantitative recommendations of intake. It is questionable to recommend in developing countries that a fixed proportion of dietary energy be derived from simple sugars, due to the high prevalence of deficient energy intake, cultural habits, and regional differences in food intake and physical activity. In relation to recommendations of complex carbohydrates, it should be considered that their absorption is influenced by many factors inherent to the individual and to the foods. Fiber is defined as a series of different substances derived from tissue structures, cellular residues and undigested chemical substances that may be partially utilized after intestinal bacteria have acted on them. There is not a clear definition of the chemical composition of fiber, but it consists mainly of polysaccharides (such as cellulose, hemicellulose and pectins), lignin and end products of the interactions of various food components. The effects of fiber, such as control of food intake, regulation of gastrointestinal transit, post-prandial blood concentrations of cholesterol, glucose and insulin, flatulence and alterations in nutrient bioavailability are due to various physical properties inherent to its chemical components. Impairment of nutrient absorption may be harmful, mainly among populations whose food intake is lower than their energy needs, and with a high fiber content. This may be particularly important in pregnant women, growing children and the elderly, and should be considered when making nutrient recommendations. A precise knowledge of fiber is also important to calculate the real energy value of foods, mainly for two reasons: 1

  18. Fiber optic detector

    SciTech Connect

    Partin, J.K.; Ward, T.E.; Grey, A.E.

    1990-12-31

    This invention is comprised of a portable fiber optic detector that senses the presence of specific target chemicals by exchanging the target chemical for a fluorescently-tagged antigen that is bound to an antibody which is in turn attached to an optical fiber. Replacing the fluorescently-tagged antigen reduces the fluorescence so that a photon sensing detector records the reduced light level and activates an appropriate alarm or indicator.

  19. Fiber optic detector

    NASA Astrophysics Data System (ADS)

    Partin, Judy K.; Ward, Thomas E.; Grey, Alan E.

    1990-04-01

    This invention is comprised of a portable fiber optic detector that senses the presence of specific target chemicals by exchanging the target chemical for a fluorescently-tagged antigen that is bound to an antibody which is in turn attached to an optical fiber. Replacing the fluorescently-tagged antigen reduces the fluorescence so that a photon sensing detector records the reduced light level and activates an appropriate alarm or indicator.

  20. Infrared fiber optic materials

    NASA Technical Reports Server (NTRS)

    Feigelson, Robert S.

    1987-01-01

    The development of IR fiber optics for use in astronomical and other space applications is summarized. Candidate materials were sought for use in the 1 to 200 micron and the 200 to 1000 micron wavelength range. Synthesis and optical characterization were carried out on several of these materials in bulk form. And the fabrication of a few materials in single crystal fiber optic form were studied.

  1. Production of mullite fibers

    NASA Technical Reports Server (NTRS)

    Tucker, Dennis S. (Inventor); Sparks, J. Scott (Inventor)

    1991-01-01

    Disclosed here is a process for making mullite fibers wherein a hydrolizable silicon compound and an aluminum compound in the form of a difunctional aluminum chelate are hydrolized to form sols using water and an alcohol with a catalytic amount of hydrochloric acid. The sols are mixed in a molar ratio of aluminum to silicon of 3 to 1 and, under polycondensation conditions, a fibrous gel is formed. From this gel the mullite fibers can be produced.

  2. Fiber optics welder

    DOEpatents

    Higgins, R.W.; Robichaud, R.E.

    A system is described for welding fiber optic waveguides together. The ends of the two fibers to be joined together are accurately, collinearly aligned in a vertical orientation and subjected to a controlled, diffuse arc to effect welding and thermal conditioning. A front-surfaced mirror mounted at a 45/sup 0/ angle to the optical axis of a stereomicroscope mounted for viewing the junction of the ends provides two orthogonal views of the interface during the alignment operation.

  3. Squeezing in Optical Fibers

    NASA Astrophysics Data System (ADS)

    Boivin, Luc

    The generation of squeezed radiation in single -mode optical fibers is discussed. A self-consistent theory for the quantum propagation of pulses in dispersive and Raman active fibers is developed. A numerical implementation of the corresponding linearized noise theory is presented. This code was used to design a new fiber squeezer operating at 830nm. A closed-form solution to the nonlinear, stochastic and integro-differential equation for the quantum envelope is found at zero dispersion. We use this solution to study the resonance-fluorescence spectrum of a fiber excited by a monochromatic laser field. We also evaluate the mean field and the squeezing level for fiber lengths where the linearized approximation is no longer valid. The predictions of this continuous-time theory are compared with those of the discretized-time model. We show that quantum revivals predicted by the latter are spurious. We show that the linearized approximation in the soliton regime is valid for nonlinear phase shifts up to n_0^ {1/4}. The noise of the four soliton operators is shown to be minimized in a Poisson-Gaussian soliton state. We propose a new method for generating squeezed vacuum using a low birefringence fiber. This method relies on cross-phase modulation between modes with orthogonal polarizations, and does not require a interferometric geometry. We predict the nonlinear depolarization of an intense linearly polarized pulse coupled into a low birefringence fiber due to its interaction with quantum noise. Finally, progress in the construction of a fiber squeezer driven by a high repetition rate modelocked Ti:Sapphire laser is reported. (Copies available exclusively from MIT Libraries, Rm. 14-0551, Cambridge, MA 02139-4307. Ph. 617-253-5668; Fax 617-253-1690.).

  4. Emergence of fiber supercapacitors.

    PubMed

    Yu, Dingshan; Qian, Qihui; Wei, Li; Jiang, Wenchao; Goh, Kunli; Wei, Jun; Zhang, Jie; Chen, Yuan

    2015-02-01

    Supercapacitors (SCs) are energy storage devices which have high power density and long cycle life. Conventional SCs have two-dimensional planar structures. As a new family of SCs, fiber SCs utilize one-dimensional cylindrically shaped fibers as electrodes. They have attracted significant interest since 2011 and have shown great application potential either as micro-scale devices to complement or even replace micro-batteries in miniaturized electronics and microelectromechanical systems or as macro-scale devices for wearable electronics or smart textiles. This tutorial review provides an essential introduction to this new field. We first introduce the basics of performance evaluation for fiber SCs as a foundation to understand different research approaches and the diverse performance metrics reported in the literature. Next, we summarize the current state-of-the-art progress in structure design and electrode fabrication of fiber SCs. This is followed by a discussion on the integration of multiple fiber SCs and the combination with other energy harvesting or storage devices. Last, we present our perspectives on the future development of fiber SCs and highlight key technical challenges with the hope of stimulating further research progress. PMID:25420877

  5. Chiral fiber optical isolator

    NASA Astrophysics Data System (ADS)

    Kopp, Victor I.; Zhang, Guoyin; Zhang, Sheng; Genack, Azriel Z.; Neugroschl, Dan

    2009-02-01

    We propose an in-fiber chiral optical isolator based on chiral fiber polarizer technology and calculate its performance by incorporating the magnetic field into the scattering matrix. The design will be implemented in a special preform, which is passed through a miniature heat zone as it is drawn and twisted. The birefringence of the fiber is controlled by adjusted the diameter of a dual-core optical fiber. By adjusting the twist, the fiber can convert linear to circular polarization and reject one component of circular polarization. In the novel central portion of the isolator, the fiber diameter is large. The effective birefringence of the circular central core with high Verdet constant embedded in an outer core of slightly smaller index of refraction is small. The central potion is a non-reciprocal polarization converter which passes forward traveling left circularly polarized (LCP) light as LCP, while converting backward propagating LCP to right circularly polarized (RCP) light. Both polarizations of light traveling backwards are scattered out of the isolator. Since it is an all-glass structure, we anticipate that the isolator will be able to handle several watts of power and will be environmentally robust.

  6. Carbon fiber modification

    NASA Technical Reports Server (NTRS)

    Thompson, T. E.

    1979-01-01

    The effect of several chemical treatments on the electrical and mechanical properties of carbon fibers was investigated with an optimum goal of increasing the electrical resistivity by a factor of 1000 without appreciably changing the mechanical properties. It was possible to effect resistivity increases from 10 to 50 percent without adversely affecting the tensile strength or Young's modulus for T-300 and C-6000 PAN fibers by treatments with either AlCl3 or nitric acid mixtures. Larger increases in the resistivity were produced with pitch fibers treated with nitric acid mixtures. This treatment also produced a partial decomposition of the pitch fiber and deterioration of the mechanical properties. The rationale behind the approch was to immobilize the conductivity producing pi electrons in the microscopic aromatic structure of the carbon fibers without destroying the strength producing sigma bonds. The investigations indicate that certain chemical treatments can produce such results, but the total reduction in the electrical conductivity which was achieved was not large enough to impact on problems which might arise from the high conductivities of the fibers.

  7. Fiber optics for controls

    NASA Technical Reports Server (NTRS)

    Seng, Gary T.

    1987-01-01

    The challenge of those involved in control-system hardware development is to accommodate an ever-increasing complexity in aircraft control, while limiting the size and weight of the components and improving system reliability. A technology that displays promise towards this end is the area of fiber optics for controls. The primary advantages of employing optical fibers, passive optical sensors, and optically controlled actuators are weight and volume reduction, immunity from electromagnetic effects, superior bandwidth capabilities, and freedom from short circuits and sparking contacts. Since 1975, NASA Lewis has performed in-house, contract, and grant research in fiber optic sensors, high-temperature electro-optic switches, and fly-by-light control-system architecture. Passive optical sensor development is an essential yet challenging area of work and has therefore received much attention during this period. A major effort to develop fly-by-light control-system technology, known as the Fiber-Optic Control System Integration (FOCSI) program, was initiated in 1985 as a cooperative effort between NASA and DOD. Phase 1 of FOCSI, completed in 1986, was aimed at the design of a fiber-optic integrated propulsion/flight control system. Phase 2, yet to be initiated, will provide subcomponent and system development, and a system engine test. In addition to a summary of the benefits of fiber optics, the FOCSI program, sensor advances, and future directions in the NASA Lewis program will be discussed.

  8. Advances in infrared fibers

    NASA Astrophysics Data System (ADS)

    Tao, Guangming; Abouraddy, Ayman F.

    2015-05-01

    Infrared (IR) fibers that transmit radiation at wavelengths from ~ 2 μm up to ~ 25 μm, a spectrum that extends across both the mid-IR (MIR) and far-IR (FIR), has gained extensive attention concomitant with the recent availability of MIR semiconductors sources and detectors. Chalcogenide glasses (ChGs) are a leading candidate for IR fibers by virtue of their wide optical transmission windows and high nonlinearity in the IR region. After extensive studies since the 1960s, the development and applications of ChG IR fibers are primarily hindered by their unfavorable mechanical properties. Here, we summarize our recent advances in low-cost, robust multimaterial ChG IR fibers with broad transmission windows and low optical losses, based on our multimaterial fiber preforms produced by several fabrication methodologies. Hundreds of meters of fibers are thermally drawn in an ambient atmosphere with desired step-index structure from a macroscopic multimaterial preform that contains few grams of ChG. These simple and efficient processes overcome many of the traditional obstacles, and therefore enable rapid production in an industrial setting.

  9. Electrospun Amplified Fiber Optics

    PubMed Central

    2015-01-01

    All-optical signal processing is the focus of much research aiming to obtain effective alternatives to existing data transmission platforms. Amplification of light in fiber optics, such as in Erbium-doped fiber amplifiers, is especially important for efficient signal transmission. However, the complex fabrication methods involving high-temperature processes performed in a highly pure environment slow the fabrication process and make amplified components expensive with respect to an ideal, high-throughput, room temperature production. Here, we report on near-infrared polymer fiber amplifiers working over a band of ∼20 nm. The fibers are cheap, spun with a process entirely carried out at room temperature, and shown to have amplified spontaneous emission with good gain coefficients and low levels of optical losses (a few cm–1). The amplification process is favored by high fiber quality and low self-absorption. The found performance metrics appear to be suitable for short-distance operations, and the large variety of commercially available doping dyes might allow for effective multiwavelength operations by electrospun amplified fiber optics. PMID:25710188

  10. Study on basalt fiber parameters affecting fiber-reinforced mortar

    NASA Astrophysics Data System (ADS)

    Orlov, A. A.; Chernykh, T. N.; Sashina, A. V.; Bogusevich, D. V.

    2015-01-01

    This article considers the effect of different dosages and diameters of basalt fibers on tensile strength increase during bending of fiberboard-reinforced mortar samples. The optimal dosages of fiber, providing maximum strength in bending are revealed. The durability of basalt fiber in an environment of cement, by means of microscopic analysis of samples of fibers and fiberboard-reinforced mortar long-term tests is examined. The article also compares the behavior of basalt fiber in the cement stone environment to a glass one and reveals that the basalt fiber is not subject to destruction.

  11. The optimal fiber volume fraction and fiber-matrix property compatibility in fiber reinforced composites

    NASA Technical Reports Server (NTRS)

    Pan, Ning

    1992-01-01

    Although the question of minimum or critical fiber volume fraction beyond which a composite can then be strengthened due to addition of fibers has been dealt with by several investigators for both continuous and short fiber composites, a study of maximum or optimal fiber volume fraction at which the composite reaches its highest strength has not been reported yet. The present analysis has investigated this issue for short fiber case based on the well-known shear lag (the elastic stress transfer) theory as the first step. Using the relationships obtained, the minimum spacing between fibers is determined upon which the maximum fiber volume fraction can be calculated, depending on the fiber packing forms within the composites. The effects on the value of this maximum fiber volume fraction due to such factors as fiber and matrix properties, fiber aspect ratio and fiber packing forms are discussed. Furthermore, combined with the previous analysis on the minimum fiber volume fraction, this maximum fiber volume fraction can be used to examine the property compatibility of fiber and matrix in forming a composite. This is deemed to be useful for composite design. Finally some examples are provided to illustrate the results.

  12. Optical fiber stripper positioning apparatus

    DOEpatents

    Fyfe, Richard W.; Sanchez, Jr., Amadeo

    1990-01-01

    An optical fiber positioning apparatus for an optical fiber stripping device is disclosed which is capable of providing precise axial alignment between an optical fiber to be stripped of its outer jacket and the cutting blades of a stripping device. The apparatus includes a first bore having a width approximately equal to the diameter of an unstripped optical fiber and a counter bore axially aligned with the first bore and dimensioned to precisely receive a portion of the stripping device in axial alignment with notched cutting blades within the stripping device to thereby axially align the notched cutting blades of the stripping device with the axis of the optical fiber to permit the notched cutting blades to sever the jacket on the optical fiber without damaging the cladding on the optical fiber. In a preferred embodiment, the apparatus further includes a fiber stop which permits determination of the length of jacket to be removed from the optical fiber.

  13. Self Similar Optical Fiber

    NASA Astrophysics Data System (ADS)

    Lai, Zheng-Xuan

    This research proposes Self Similar optical fiber (SSF) as a new type of optical fiber. It has a special core that consists of self similar structure. Such a structure is obtained by following the formula for generating iterated function systems (IFS) in Fractal Theory. The resulted SSF can be viewed as a true fractal object in optical fibers. In addition, the method of fabricating SSF makes it possible to generate desired structures exponentially in numbers, whereas it also allows lower scale units in the structure to be reduced in size exponentially. The invention of SSF is expected to greatly ease the production of optical fiber when a large number of small hollow structures are needed in the core of the optical fiber. This dissertation will analyze the core structure of SSF based on fractal theory. Possible properties from the structural characteristics and the corresponding applications are explained. Four SSF samples were obtained through actual fabrication in a laboratory environment. Different from traditional conductive heating fabrication system, I used an in-house designed furnace that incorporated a radiation heating method, and was equipped with automated temperature control system. The obtained samples were examined through spectrum tests. Results from the tests showed that SSF does have the optical property of delivering light in a certain wavelength range. However, SSF as a new type of optical fiber requires a systematic research to find out the theory that explains its structure and the associated optical properties. The fabrication and quality of SSF also needs to be improved for product deployment. As a start of this extensive research, this dissertation work opens the door to a very promising new area in optical fiber research.

  14. Natural Fiber Composites: A Review

    SciTech Connect

    Westman, Matthew P.; Fifield, Leonard S.; Simmons, Kevin L.; Laddha, Sachin; Kafentzis, Tyler A.

    2010-03-07

    The need for renewable fiber reinforced composites has never been as prevalent as it currently is. Natural fibers offer both cost savings and a reduction in density when compared to glass fibers. Though the strength of natural fibers is not as great as glass, the specific properties are comparable. Currently natural fiber composites have two issues that need to be addressed: resin compatibility and water absorption. The following preliminary research has investigated the use of Kenaf, Hibiscus cannabinus, as a possible glass replacement in fiber reinforced composites.

  15. ZBLAN Fiber Phase B Study

    NASA Technical Reports Server (NTRS)

    Workman, Gary L.; Smith, Guy A.

    1997-01-01

    A Phase B feasibility study will be performed for the study of the effects of microgravity on the preform processing and fiber pulling of ZBLAN optical glass. Continuing from the positive results achieved in the fiber annealing experiments in 20 second intervals at 0.001 g on the KC-135 and the 5 minute experiments on the SPAR rocket, experiments will continue to work towards design of a fiber sting to initiate fiber pulling operations in space. Anticipated results include less homogeneous nucleation than ground-based annealed fibers. Infrared Fiber Systems and Galileo are the participating industrial investigators.

  16. Enhanced radiation resistant fiber optics

    DOEpatents

    Lyons, P.B.; Looney, L.D.

    1993-11-30

    A process for producing an optical fiber having enhanced radiation resistance is provided, the process including maintaining an optical fiber within a hydrogen-containing atmosphere for sufficient time to yield a hydrogen-permeated optical fiber having an elevated internal hydrogen concentration, and irradiating the hydrogen-permeated optical fiber at a time while the optical fiber has an elevated internal hydrogen concentration with a source of ionizing radiation. The radiation source is typically a cobalt-60 source and the fiber is pre-irradiated with a dose level up to about 1000 kilorads of radiation. 4 figures.

  17. Enhanced radiation resistant fiber optics

    DOEpatents

    Lyons, Peter B.; Looney, Larry D.

    1993-01-01

    A process for producing an optical fiber having enhanced radiation resitance is provided, the process including maintaining an optical fiber within a hydrogen-containing atmosphere for sufficient time to yield a hydrogen-permeated optical fiber having an elevated internal hydrogen concentration, and irradiating the hydrogen-permeated optical fiber at a time while the optical fiber has an elevated internal hydrogen concentration with a source of ionizing radiation. The radiation source is typically a cobalt-60 source and the fiber is pre-irradiated with a dose level up to about 1000 kilorads of radiation.

  18. Integrated Optofluidic Multimaterial Fibers

    NASA Astrophysics Data System (ADS)

    Stolyarov, Alexander Mark

    The creation of integrated microphotonic devices requires a challenging assembly of optically and electrically disparate materials into complex geometries with nanometer-scale precision. These challenges are typically addressed by mature wafer-based fabrication methods, which while versatile, are limited to low-aspect-ratio structures and by the inherent complexity of sequential processing steps. Multimaterial preform-to-fiber drawing methods on the other hand present unique opportunities for realizing optical and optoelectronic devices of extended length. Importantly, these methods allow for monolithic integration of all the constituent device components into complex architectures. My research has focused on addressing the challenges and opportunities associated with microfluidic multimaterial fiber structures and devices. Specifically: (1) A photonic bandgap (PBG) fiber is demonstrated for single mode transmission at 1.55 microm with 4 dB/m losses. This fiber transmits laser pulses with peak powers of 13.5 MW. (Chapter 2) (2) A microfluidic fiber laser, characterized by purely radia l emission is demonstrated. The laser cavity is formed by an axially invariant, 17-period annular PBG structure with a unit cell thickness of 160nm. This laser is distinct from traditional lasers with cylindrically symmetric emission, which rely almost exclusively on whispering gallery modes, characterized by tangential wavevectors. (Chapter 4) (3) An array of independently-controlled liquid-crystal microchannels flanked by viscous conductors is integrated in the fiber cladding and encircles the PBG laser cavity in (2). The interplay between the radially-emitting laser and these liquid-crystal modulators enables controlled directional emission around a full azimuthal angular range. (Chapter 4) (4) The electric potential profile along the length of the electrodes in (3) is characterized and found to depend on frequency. This frequency dependence presents a new means to tune the

  19. Image fiber skew characteristics

    NASA Astrophysics Data System (ADS)

    Nakamura, Moriya; Otsubo, Toshimichi; Kitayama, Ken-ichi

    2000-04-01

    Skew of an image fiber, which has more than ten thousands of cores in a common cladding, was measured by a novel measurement method for the first time. This method can measure the time-of-flight difference between individual cores over the whole area of an image circle. The measurement results reveals that a test 100-m-long image fiber has skew of 5 ps/m, and the time-of-flight distributes randomly in the whole area of the image circle due to nonuniformity of the core dimension. It is also experimentally shown that the skew of an image fiber increases by bending. The theoretical analysis reveals that the bending-induced skew depends neither on the radius of curvature nor the shape of the curve but it depends only on the number of turns it is wound. The numerical calculation of skew by using typical parameters of image fibers shows that the winding have to be restricted to less than 12.5 turns to achieve a transmission speed of over 1 Gbps/ch. Lastly we propose twisted image fiber and a 8-shaped bobbin to suppress the skew due to bending.

  20. Continuous fiber thermoplastic prepreg

    NASA Technical Reports Server (NTRS)

    Wilson, Maywood L. (Inventor); Johnson, Gary S. (Inventor)

    1993-01-01

    A pultrusion machine employing a corrugated impregnator vessel to immerse multiple, continuous strand, fiber tow in an impregnating material, and an adjustable metered exit orifice for the impregnator vessel to control the quantity of impregnating material retained by the impregnated fibers, is provided. An adjustable height insert retains transverse rod elements within each depression of the corrugated vessel to maintain the individual fiber tows spread and in contact with the vessel bottom. A series of elongated heating dies, transversely disposed on the pultrusion machine and having flat heating surfaces with radiused edges, ensure adequate temperature exposed dwell time and exert adequate pressure on the impregnated fiber tows, to provide the desired thickness and fiber/resin ratio in the prepreg formed. The prepreg passing through the pulling mechanism is wound on a suitable take-up spool for subsequent use. A formula is derived for determining the cross sectional area opening of the metering device. A modification in the heating die system employs a heated nip roller in lieu of one of the pressure applying flat dies.

  1. Congenital fiber type disproportion.

    PubMed

    Kissiedu, Juliana; Prayson, Richard A

    2016-04-01

    Type I muscle fiber atrophy in childhood can be encountered in a variety of neuromuscular disorders. Congenital fiber type disproportion (CFTD) is one such condition which presents as a nonprogressive muscle weakness. The diagnosis is often made after excluding other differential diagnostic considerations. We present a 2-year-9-month-old full term boy who presented at 2 months with an inability to turn his head to the right. Over the next couple of years, he showed signs of muscle weakness, broad based gait and a positive Gower's sign. He had normal levels of creatine kinase and normal electromyography. A biopsy of the vastus lateralis showed a marked variation in muscle fiber type. The adenosine triphosphate (ATP)-ase stains highlighted a marked type I muscle atrophy with rare scattered atrophic type II muscle fibers. No abnormalities were observed on the nicotinamide adenine dinucleotide (NADH), succinate dehydrogenase (SDH) or cytochrome oxidase stained sections. Ragged red fibers were not present on the trichrome stain. Abnormalities of glycogen or lipid deposition were not observed on the periodic acid-Schiff or Oil-Red-O stains. Immunostaining for muscular dystrophy associated proteins showed normal staining. Ultrastructural examination showed a normal arrangement of myofilaments, and a normal number and morphology for mitochondria. A diagnosis of CFTD was made after excluding other causes of type I atrophy including congenital myopathy. The lack of specific clinical and genetic disorder associated with CFTD suggests that it is a spectrum of a disease process and represents a diagnosis of exclusion. PMID:26526626

  2. Directionally solidified mullite fibers

    SciTech Connect

    Sayir, A.; Farmer, S.C.

    1995-10-01

    Directionally solidified fibers with nominal mullite compositions of 3Al{sub 2}O{sub 3} {center_dot} 2SiO{sub 2} were grown by the laser heated float zone (LHFZ) method at NASA Lewis. High resolution digital images from an optical microscope evidence the formation of a liquid-liquid miscibility gap during crystal growth. Experimental evidence shows that the formation of mullite in aluminosilicate melts is in fact preceded by liquid immiscibility. The average fiber tensile strength is 1.15 GPa at room temperature. The mullite fibers retained 80% of their room temperature tensile strength at 1,450 C. SEM analysis revealed that the fibers were strongly faceted and that the facets act as critical flaws. Examined in TEM, these mullite single crystals are free of dislocations, low angle boundaries and voids. Single crystal mullite showed a high degree of oxygen vacancy ordering. Regardless of the starting composition, the degree of order observed in polycrystalline fibers was lower than that observed in the mullite single crystals.

  3. Tapered fiber bundle couplers for high-power fiber amplifiers

    NASA Astrophysics Data System (ADS)

    Sliwinska, Dorota; Kaczmarek, Pawel; Abramski, Krzysztof M.

    2014-12-01

    In this work, we would like to demonstrate our results on performing (6+1)x1 tapered fiber bundle combiners using a trielectrode fiber splicing system. In our combiners we have used 9/80 μm (core/clad) diameter fibers as single-mode signal input ports. Using this fiber, instead of a conventional 9/125 μm single-mode fiber allowed us to reduce the taper ratio and therefore significantly increase the signal transmission. We have also performed power combiner which is based on the LMA fibers: input signal fiber 20/125μm and passive double clad fiber 25/300 μm at the output.

  4. Fiber optic calorimetry

    SciTech Connect

    Rudy, C.; Bayliss, S.; Bracken, D.; Bush, J.; Davis, P.

    1998-01-01

    A twin-bridge calorimeter using optical fiber as the sensor element was constructed and tested. This system demonstrates the principle and capability of using fiber for heat-flow measurements of special nuclear material. This calorimeter uses piezoelectric-generated phase-carrier modulation with subsequent electronic signal processing to allow phase shifts as small as 1 microradian ({mu}rad) to be measured. The sensing element consists of 21-m lengths of single-mode optical fiber wrapped around sample and reference chambers. The sensitivity of the calorimeter was determined to be 74 radians (rad) of phase shift per milliwatt of thermal power. One milliwatt of thermal power is equivalent to 400 mg of plutonium (6% {sup 240}Pu). The system noise base was about 0.2 rad, equivalent to about 1 mg of plutonium.

  5. Fiber Optic Calorimetry

    SciTech Connect

    Rudy, C.; Bayliss, S.; Bracken, D.; Bush, J.; Davis, P.

    1997-12-12

    A twin-bridge calorimeter using optical fiber as the sensor element was constructed and tested. This system demonstrates the principle and capability of using optical fibers for heat-flow measurements of special nuclear material. This calorimeter uses piezoelectric-generated phase-carrier modulation with subsequent electronic signal processes to allow phase shifts as small as 1 microradian ({micro}rad) to be measured. The sensing element consists of 21-m lengths of single-mode optical fiber wrapped around sample and reference chambers. The sensitivity of the calorimeter was determined to be 74 radians (rad) of phase shift per milliwatt of thermal power. One milliwatt of thermal power is equivalent to 400 mg of plutonium (6% {sup 240}Pu). The system noise base was about 0.2 rad, equivalent to about 1 mg of plutonium.

  6. Carbon Fiber Composites

    NASA Technical Reports Server (NTRS)

    1997-01-01

    HyComp(R), Inc. development a line of high temperature carbon fiber composite products to solve wear problems in the harsh environment of steel and aluminum mills. WearComp(R), self-lubricating composite wear liners and bushings, combines carbon graphite fibers with a polyimide binder. The binder, in conjunction with the fibers, provides the slippery surface, one that demands no lubrication, yet wears at a very slow rate. WearComp(R) typically lasts six to ten times longer than aluminum bronze. Unlike bronze, WearComp polishes the same surface and imparts a self-lube film for years of service. It is designed for continuous operation at temperatures of 550 degrees Fahrenheit and can operate under high compressive loads.

  7. Fiber optic hydrogen sensor

    NASA Astrophysics Data System (ADS)

    Jung, Chuck C.; Saaski, Elric W.; McCrae, David A.

    1998-09-01

    This paper describes a novel fiber optic-based hydrogen sensor. The sensor consists of a thin-film etalon, constructed on the distal end of a fiber optic. The exterior mirror of the etalon is palladium or a palladium-alloy, which undergoes an optical change upon exposure to hydrogen. Data is presented on fiber optic sensors constructed with palladium and several alloys of palladium. The linearity of the optical response of these sensors to hydrogen is examined. Etalons made with pure palladium are found to be desirable for sensing low concentrations of hydrogen, or for one-time exposure to high concentrations of hydrogen. Etalons made from palladium alloys are found to be more desirable in applications were repeated cycling in high concentrations of hydrogen occurs.

  8. Fiber coating with suspensions

    NASA Astrophysics Data System (ADS)

    Abkarian, Manouk; Nunes, Janine K.; Stone, Howard A.

    2003-11-01

    The basic features of fiber coating with Newtonian fluids are well characterized at low capillary numbers by the Landau-Levich-Derjaguin analysis. Several extensions have been reported including studies of the influence of polymers, surfactants, and emulsions. Here we present an experimental study of fiber coating with suspensions of micron-sized particles where we perform direct visualization of the coating process using fluorescent particles. The addition of particles to the coating liquid produce several novel effects including (a) accumulation of particles in the neighborhood of the meniscus, which changes the dynamics of the coating process, and (b) crystallization can occur on the fiber, in some cases in the form of a continuous film that is at most a few particles thick, and which depends on capillary number. These results using continuous withdrawal will be contrasted with those reported in the literature for colloidal cystallization produced by evaporative processes.

  9. Optical fiber laser

    SciTech Connect

    Snitzer, E.

    1988-10-25

    This patent describes an optical fiber laser comprising: a gain cavity including a single mode optical fiber of given length and index of refraction and a cladding surrounding the core and having an index of refraction lower than that of the core. The core comprising a host material having incorporated therein a predetermined concentration of just erbium oxide having a fluorescence spectrum with a peak emission line at 1.54 micrometers; filter means optically coupled to each end of the fiber gain cavity for providing feedback in the cavity at the peak emission line of the erbium oxide and for permitting energy to be introduced into the cavity at the absorption band of the erbium oxide in the region of 1.45 to 1.53 micrometers; and a laser diode optically coupled to one end of the core for pumping energy into the end of the gain cavity so that the gain cavity oscillates at just the peak emission line.

  10. Optical fiber switch

    DOEpatents

    Early, James W.; Lester, Charles S.

    2002-01-01

    Optical fiber switches operated by electrical activation of at least one laser light modulator through which laser light is directed into at least one polarizer are used for the sequential transport of laser light from a single laser into a plurality of optical fibers. In one embodiment of the invention, laser light from a single excitation laser is sequentially transported to a plurality of optical fibers which in turn transport the laser light to separate individual remotely located laser fuel ignitors. The invention can be operated electro-optically with no need for any mechanical or moving parts, or, alternatively, can be operated electro-mechanically. The invention can be used to switch either pulsed or continuous wave laser light.

  11. Probabilistic Fiber Composite Micromechanics

    NASA Technical Reports Server (NTRS)

    Stock, Thomas A.

    1996-01-01

    Probabilistic composite micromechanics methods are developed that simulate expected uncertainties in unidirectional fiber composite properties. These methods are in the form of computational procedures using Monte Carlo simulation. The variables in which uncertainties are accounted for include constituent and void volume ratios, constituent elastic properties and strengths, and fiber misalignment. A graphite/epoxy unidirectional composite (ply) is studied to demonstrate fiber composite material property variations induced by random changes expected at the material micro level. Regression results are presented to show the relative correlation between predictor and response variables in the study. These computational procedures make possible a formal description of anticipated random processes at the intra-ply level, and the related effects of these on composite properties.

  12. Carbon Fibers Conductivity Studies

    NASA Technical Reports Server (NTRS)

    Yang, C. Y.; Butkus, A. M.

    1980-01-01

    In an attempt to understand the process of electrical conduction in polyacrylonitrile (PAN)-based carbon fibers, calculations were carried out on cluster models of the fiber consisting of carbon, nitrogen, and hydrogen atoms using the modified intermediate neglect of differential overlap (MINDO) molecular orbital (MO) method. The models were developed based on the assumption that PAN carbon fibers obtained with heat treatment temperatures (HTT) below 1000 C retain nitrogen in a graphite-like lattice. For clusters modeling an edge nitrogen site, analysis of the occupied MO's indicated an electron distribution similar to that of graphite. A similar analysis for the somewhat less stable interior nitrogen site revealed a partially localized II electron distribution around the nitrogen atom. The differences in bonding trends and structural stability between edge and interior nitrogen clusters led to a two-step process proposed for nitrogen evolution with increasing HTT.

  13. Containerless glass fiber processing

    NASA Technical Reports Server (NTRS)

    Ethridge, E. C.; Naumann, R. J.

    1986-01-01

    An acoustic levitation furnace system is described that was developed for testing the feasibility of containerless fiber pulling experiments. It is possible to levitate very dense materials such as platinum at room temperature. Levitation at elevated temperatures is much more difficult. Samples of dense heavy metal fluoride glass were levitated at 300 C. It is therefore possible that containerless fiber pulling experiments could be performed. Fiber pulling from the melt at 650 C is not possible at unit gravity but could be possible at reduced gravities. The Acoustic Levitation Furnace is described, including engineering parameters and processing information. It is illustrated that a shaped reflector greatly increases the levitation force aiding the levitation of more dense materials.

  14. Pyrolysis Pathways of Sulfonated Polyethylene, an Alternative Carbon Fiber Precursor

    SciTech Connect

    Younker, Jarod M; Saito, Tomonori; Hunt, Marcus A; Beste, Ariana; Naskar, Amit K

    2013-01-01

    Sulfonated polyethylene is an emerging precursor for the production of carbon fibers. Pyrolysis of sulfonated polyethylene was characterized by thermogravimetric analysis (TGA). n-heptane-4-sulfonic acid (H4S) was selected as a model compound for the study of sulfonated polyethylene. Density functional theory and conventional transition state theory were used to determine the rate constants of pyrolysis for H4S from 300-1000 K. Multiple reaction channels from two different mechanisms were explored: 1) internal five-centered elimination (Ei 5) and 2) radical chain reaction. The pyrolysis of H4S was simulated with kinetic Monte Carlo (kMC) to obtain TGA plots that compared favorably to experiment. We observed that at tem- peratures < 550 K, the radical mechanism was dominant and yielded the trans-alkene, whereas cis-alkene was formed at higher temperatures from the internal elimination. The maximum rates of % mass loss became independent of initial OH radical concentration at 440-480 K. Experimentally, the maximum % mass loss occurred from 440-460 K (heating rate dependent). Activation energies derived from the kMC-simulated TGAs of H4S (26-29 kcal/mol) agreed with experiment for sulfonated polyethylene ( 31 kcal/mol). The simulations revealed that in this region, decomposition of radical HOSO2 became competitive to H abstraction by HOSO2, making OH the carrying radical for the reaction chain. The maximum rate of % mass loss for internal elimination was observed at temperatures > 600 K. Low-scale carbonization utilizes temperatures < 620 K; thus, internal elimination will not be competitive. Ei5 elimination has been studied for sulfoxides and sulfones, but this represents the first study of internal elimination in sulfonic acids. Nonlinear Arrhenius plots were found for all bimolecular reactions. The most significant nonlinear behavior was observed for reactions where the barrier was small. For reactions with low activation barriers, nonlinearity was traced to

  15. The crucial fiber components and gain fiber for high power ytterbium-doped fiber laser

    NASA Astrophysics Data System (ADS)

    Liao, Lei; Liu, Peng; Xing, Ying-Bin; Wang, Yi-Bo; Dai, Neng-Li; Li, Jin-Yan; He, Bing; Zhou, Jun

    2015-08-01

    We have demonstrated a kW continuous-wave ytterbium-doped all-fiber laser oscillator with 7×1 fused fiber bundle combiner, fiber Bragg grating (FBG) and double-clad gain fiber fabricated by corresponding technologies. The results of experiment that the oscillator had operated at 1079.48nm with 80.94% slope efficiency without the influence of temperature and non-linear effects indicate that fiber components and gain fiber were suitable to high power environment. No evidence of the signal power roll-over showed that this oscillator possess the capacity to highest output with available pump power.

  16. Automated fiber pigtailing machine

    DOEpatents

    Strand, O.T.; Lowry, M.E.

    1999-01-05

    The Automated Fiber Pigtailing Machine (AFPM) aligns and attaches optical fibers to optoelectronic (OE) devices such as laser diodes, photodiodes, and waveguide devices without operator intervention. The so-called pigtailing process is completed with sub-micron accuracies in less than 3 minutes. The AFPM operates unattended for one hour, is modular in design and is compatible with a mass production manufacturing environment. This machine can be used to build components which are used in military aircraft navigation systems, computer systems, communications systems and in the construction of diagnostics and experimental systems. 26 figs.

  17. Fiber optic interferometric accelerometers

    SciTech Connect

    Vohra, S.T.; Danver, B.; Tveten, A.; Dandridge, A.

    1996-04-01

    Recent progress on the development of flexural disk based fiber optic acceleration sensors is reported. Appropriate geometric considerations have resulted in fiber optic accelerometers with many desirable features including (i) high sensitivity ({approx_gt}20 dB rerad/g), (ii) flat frequency response (200 Hz to {approx_gt}10 kHz), and (iii) low pressure ({lt}{minus}180 dB rerad/{mu}Pa) and transverse sensitivity ({lt}{minus}30 dB). Alternate transducer designs are discussed and preliminary results reported. Various optical multiplexing schemes for accelerometer arrays are discussed. {copyright} {ital 1996 American Institute of Physics.}

  18. Silicon fiber optic sensors

    DOEpatents

    Pocha, Michael D.; Swierkowski, Steve P.; Wood, Billy E.

    2007-10-02

    A Fabry-Perot cavity is formed by a partially or wholly reflective surface on the free end of an integrated elongate channel or an integrated bounding wall of a chip of a wafer and a partially reflective surface on the end of the optical fiber. Such a constructed device can be utilized to detect one or more physical parameters, such as, for example, strain, through the optical fiber using an optical detection system to provide measuring accuracies of less than aboutb0.1%.

  19. Fiber bundle endocytoscopy

    PubMed Central

    Hughes, Michael; Chang, Tou Pin; Yang, Guang-Zhong

    2013-01-01

    Endocytoscopy is an optical biopsy technique which uses a miniaturized camera to capture white light microscopy images through an endoscope. We have developed an alternative design that instead relays images to an external camera via a coherent fiber bundle. In this paper we characterize the device and demonstrate microscopy of porcine tissue ex vivo. One advantage of our approach is the ease with which other bundle-compatible imaging modalities can be deployed simultaneously. We show this by acquiring quasi-simultaneous endocytoscopy and fluorescence confocal endomicroscopy images through a single fiber bundle. This opens up possibilities for multi-modal endomicroscopy, combining white light and fluorescence imaging. PMID:24409380

  20. Ceramic oxide fibers

    SciTech Connect

    Sowman, H.G.; Johnson, D.D.

    1985-10-01

    Polycrystalline ceramic fibers now available from commercial sources include those of Al/sub 2/O/sub 3/, Al/sub 2/O/sub 3/-SiO/sub 2/O/sub 3/, Al/sub 2/O/sub 3/-B/sub 2/O/sub 3/-SiO/sub 2/, and ZrO/sub 2/-SiO/sub 2/. Continuous filaments in roving, yarn, chopped, bulk, fabric or mat forms can be supplied. Properties and uses of these fibers are discussed. 18 references.

  1. QUARTZ FIBER ELECTROSCOPES

    DOEpatents

    Henderson, R.P.

    1956-04-17

    This patent pertains to quartz fiber electroscopes of small size for use by personnel to monitor nuclear radiation. The invention resides tn a novel way of charging the electroscope whereby the charging of the electroscope whereby the charging of the electroscope is carried out without obtaining contact with the fiber system or its support and the electroscope can therefore be constructed without a protective cap to prevent wrongful discharge. The electroscope is charged by placing a voltage between an electrode located in close proximity to the element to be charged and the electroscope me metallic case. ABSTRACTS

  2. Automated fiber pigtailing machine

    DOEpatents

    Strand, Oliver T.; Lowry, Mark E.

    1999-01-01

    The Automated Fiber Pigtailing Machine (AFPM) aligns and attaches optical fibers to optoelectonic (OE) devices such as laser diodes, photodiodes, and waveguide devices without operator intervention. The so-called pigtailing process is completed with sub-micron accuracies in less than 3 minutes. The AFPM operates unattended for one hour, is modular in design and is compatible with a mass production manufacturing environment. This machine can be used to build components which are used in military aircraft navigation systems, computer systems, communications systems and in the construction of diagnostics and experimental systems.

  3. Fiber-Optic Sensing Technology

    SciTech Connect

    Milnes, M.; Baylor, L.C.; Bave, S.

    1996-10-24

    This article offers a basic review of fiber-optic sensing technology, or more specifically, fiber-optic sensing technology as applied to the qualitative or quantitative identification of a chemical sample, and how it works,

  4. A fiber optic damage monitor

    NASA Astrophysics Data System (ADS)

    Jen, C. K.; Cielo, P.; Farnell, G. W.; Parker, M.

    A simplified fiber-optic damage monitoring system for on-line assessments of the condition of composite structural materials in F/A-18 fighters is described. Optical fibers are implanted into the composite mesh in a configuration with horizontal and vertical orientations. When light is pumped into the fibers, and failure of transmittance in either the x- or y-coordinates indicates the location of a defect at that coordinate, as revealed by the fiber damage. Attaching photodiodes to the optic fibers and connecting the entire system to a video camera and computer permits on-line monitoring of the mesh-holding panels. Sample results are provided from a system with multimode step index fibers, a VAX 11/780 computer and a video camera with a 488 x 380 cell photodiode array. Image subtraction is an effective means for fast determination of the identities of broken fibers by comparisons of images of arrays of original and damaged fibers.

  5. Boron nitride converted carbon fiber

    DOEpatents

    Rousseas, Michael; Mickelson, William; Zettl, Alexander K.

    2016-04-05

    This disclosure provides systems, methods, and apparatus related to boron nitride converted carbon fiber. In one aspect, a method may include the operations of providing boron oxide and carbon fiber, heating the boron oxide to melt the boron oxide and heating the carbon fiber, mixing a nitrogen-containing gas with boron oxide vapor from molten boron oxide, and converting at least a portion of the carbon fiber to boron nitride.

  6. Fiber Optics and Library Technology.

    ERIC Educational Resources Information Center

    Koenig, Michael

    1984-01-01

    This article examines fiber optic technology, explains some of the key terminology, and speculates about the way fiber optics will change our world. Applications of fiber optics to library systems in three major areas--linkage of a number of mainframe computers, local area networks, and main trunk communications--are highlighted. (EJS)

  7. Carbon fiber counting. [aircraft structures

    NASA Technical Reports Server (NTRS)

    Pride, R. A.

    1980-01-01

    A method was developed for characterizing the number and lengths of carbon fibers accidentally released by the burning of composite portions of civil aircraft structure in a jet fuel fire after an accident. Representative samplings of carbon fibers collected on transparent sticky film were counted from photographic enlargements with a computer aided technique which also provided fiber lengths.

  8. Direct spinning of fiber supercapacitor.

    PubMed

    Xu, Tong; Ding, Xiaoteng; Liang, Yuan; Zhao, Yang; Chen, Nan; Qu, Liangti

    2016-06-16

    A direct wet spinning approach is demonstrated for facile and continuous fabrication of a whole fiber supercapacitor using a microfluidic spinneret. The resulting fiber supercapacitor shows good electrochemical properties and possesses high flexibility and mechanical stability. This strategy paves the way for large-scale continuous production of fiber supercapacitors for weavable electronics. PMID:27251420

  9. Large core fiber optic cleaver

    DOEpatents

    Halpin, John M.

    1996-01-01

    The present invention relates to a device and method for cleaving optical fibers which yields cleaved optical fiber ends possessing high damage threshold surfaces. The device can be used to cleave optical fibers with core diameters greater than 400 .mu.m.

  10. COTTON FIBER CHEMISTRY AND TECHNOLOGY

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Annual cotton production exceeds 25 million metric tons and accounts for more than 40 percent of the textile fiber consumed worldwide. A key textile fiber for over 5000 years, this complex carbohydrate is also one of the leading crops to benefit from genetic engineering. Cotton Fiber Chemistry and...

  11. Fabrication of Optical Fiber Devices

    NASA Astrophysics Data System (ADS)

    Andres, Miguel V.

    In this paper we present the main research activities of the Laboratorio de Fibras Opticas del Instituto de Ciencia de los Materiales de la Universidad de Valencia. We show some of the main results obtained for devices based on tapered fibers, fiber Bragg gratings, acousto-optic effects and photonic crystal fibers.

  12. Shedding Light on Fiber Optics.

    ERIC Educational Resources Information Center

    Bunch, Robert M.

    1994-01-01

    Explains the principles of fiber optics as a medium for light-wave communication. Current uses of fiber systems on college campuses include voice, video, and local area network applications. A group of seven school districts in Minnesota are linked via fiber-optic cables. Other uses are discussed. (MLF)

  13. Aerogel-clad optical fiber

    DOEpatents

    Sprehn, Gregory A.; Hrubesh, Lawrence W.; Poco, John F.; Sandler, Pamela H.

    1997-01-01

    An optical fiber is surrounded by an aerogel cladding. For a low density aerogel, the index of refraction of the aerogel is close to that of air, which provides a high numerical aperture to the optical fiber. Due to the high numerical aperture, the aerogel clad optical fiber has improved light collection efficiency.

  14. Aerogel-clad optical fiber

    DOEpatents

    Sprehn, G.A.; Hrubesh, L.W.; Poco, J.F.; Sandler, P.H.

    1997-11-04

    An optical fiber is surrounded by an aerogel cladding. For a low density aerogel, the index of refraction of the aerogel is close to that of air, which provides a high numerical aperture to the optical fiber. Due to the high numerical aperture, the aerogel clad optical fiber has improved light collection efficiency. 4 figs.

  15. Fiber microelectrodes for electrophysiological recordings.

    PubMed

    Reitboeck, H J

    1983-07-01

    Methods for the fabrication of tungsten-glass and platinum-rhodium-quartz fiber microelectrodes and of fiber pipettes are described and the electrical and mechanical properties of fiber electrodes are discussed. These properties (minimal tissue damage, good single unit isolation and temporal stability) make them particularly suited for multielectrode recordings from the central nervous system. PMID:6312201

  16. Buying Fiber-Optic Networks.

    ERIC Educational Resources Information Center

    Fickes, Michael

    2003-01-01

    Describes consortia formed by college and university administrators to buy, manage, and maintain their own fiber-optic networks with the goals of cutting costs of leasing fiber-optic cable and planning for the future. Growth capacity is the real advantage of owning fiber-optic systems. (SLD)

  17. SINGLE FIBER TESTING VIA FAVIMAT

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Cotton fiber is usually tested in bulk form utilizing a mass or beard of fibers to be presented to a test instrument for measurement. There are many reasons for this, not the least of which is that handling single cotton fibers is tedious and time consuming. Cotton breeders are being pushed to mak...

  18. Pulsed Single Frequency Fiber Lasers

    NASA Astrophysics Data System (ADS)

    Jiang, Shibin

    2016-06-01

    Pulsed single frequency fiber lasers with mJ level near 1 micron, 1.55 micron and 2 micron wavelengths were demonstrated by using our proprietary highly doped fibers. These fiber lasers exhibit excellent long term stable operation with M2<1.2.

  19. Infrared Fiber Optic Sensors

    NASA Technical Reports Server (NTRS)

    1997-01-01

    Successive years of Small Business Innovation Research (SBIR) contracts from Langley Research Center to Sensiv Inc., a joint venture between Foster-Miller Inc. and Isorad, Ltd., assisted in the creation of remote fiber optic sensing systems. NASA's SBIR interest in infrared, fiber optic sensor technology was geared to monitoring the curing cycles of advanced composite materials. These funds helped in the fabrication of an infrared, fiber optic sensor to track the molecular vibrational characteristics of a composite part while it is being cured. Foster-Miller ingenuity allowed infrared transmitting optical fibers to combine with Fourier Transform Infrared spectroscopy to enable remote sensing. Sensiv probes operate in the mid-infrared range of the spectrum, although modifications to the instrument also permits its use in the near-infrared region. The Sensiv needle-probe is built to be placed in a liquid or powder and analyze the chemicals in the mixture. Other applications of the probe system include food processing control; combustion control in furnaces; and maintenance problem solving.

  20. Fiber-reinforced glass

    SciTech Connect

    Beier, W.; Markman, S.

    1997-12-01

    Fiber-reinforced glass composites are glass or glass ceramic matrices reinforced with long fibers of carbon or silicon carbide. These composites are lighter than steel but just as strong as many steel grades, and can resist higher temperatures. They also have outstanding resistance to impact, thermal shock, and wear, and can be formulated to control thermal and electrical conductivity. With proper tooling, operations such as drilling, grinding, and turning can be completed in half the time required for non-reinforced glass. Currently, fiber-reinforced glass components are primarily used for handling hot glass or molten aluminum during manufacturing operations. But FRG is also under test as an engineering material in a variety of markets, including the aerospace, automotive, and semiconductor industries. Toward this end, research is being carried out to increase the size of components that can be delivered on a production basis, to develop economical methods of achieving complex near-net shapes, and to reduce the cycle time for production of specific shapes. This article focuses on the properties and applications of fiber-reinforced glass composites.

  1. Carbon fiber study

    NASA Technical Reports Server (NTRS)

    1977-01-01

    A coordinated Federal Government action plan for dealing with the potential problems arising from the increasing use of graphite fiber reinforced composite materials in both military and civilian applications is presented. The required dissemination of declassified information and an outline of government actions to minimize the social and economic consequences of proliferated composite materials applications were included.

  2. Refractory ceramic fibers

    Integrated Risk Information System (IRIS)

    Refractory ceramic fibers ; CASRN Not found Human health assessment information on a chemical substance is included in the IRIS database only after a comprehensive review of toxicity data , as outlined in the IRIS assessment development process . Sections I ( Health Hazard Assessments for Noncarcino

  3. Fiber optic accelerometer

    NASA Technical Reports Server (NTRS)

    August, Rudolf R. (Inventor); Strahan, Virgil H. (Inventor); James, Kenneth A. (Inventor); Nichols, Donald K. (Inventor)

    1980-01-01

    An inexpensive, light weight fiber optic accelerometer to convert input mechanical motion (e.g. acceleration) into digitized optical output signals. The output of the accelerometer may be connected directly to data processing apparatus without the necessity of space consuming analog to digital interface means.

  4. Fiber optic accelerometer

    NASA Technical Reports Server (NTRS)

    Strahan, Virgil H. (Inventor); James, Kenneth A. (Inventor); Quick, William H. (Inventor)

    1983-01-01

    An inexpensive, light weight fiber optic accelerometer to convert input mechanical motion (e.g. acceleration) into digitized optical output signals. The output of the accelerometer may be connected directly to data processing apparatus without the necessity of space consuming analog to digital interface means.

  5. MICROCRYSTALLINE KERATIN FIBER

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Biopolymers compose the morphological structures generated in all living organisms. The macroscopic physical properties of biopolymers like keratin are due to molecular level structure and micorcrystallinity, the self-consistent packing arrays of molecular order within a defined space. Fiber proce...

  6. Whole Grains and Fiber

    MedlinePlus

    ... fiber. Some examples of refined grains are wheat flour, enriched bread and white rice. Most refined grains are enriched , which means that ... grains. Some examples of enriched grains are wheat flour, enriched bread and white rice. Eating whole grains provides important health benefits: Many ...

  7. Optical Fiber Spectroscopy

    NASA Technical Reports Server (NTRS)

    Buoncristiani, A. M.

    1999-01-01

    This is the final report of work done on NASA Grant NAG-1-443. The work covers the period from July 1, 1992 to December 1, 1998. During this period several distinct but related research studies and work tasks were undertaken. These different subjects are enumerated below with a description of the work done on each of them. The focus of the research was the development of optical fibers for use as distributed temperature and stress sensors. The initial concept was to utilize the utilize the temperature and stress dependence of emission from rare earth and transition metal ions substitutionally doped into crystalline or glass fibers. During the course of investigating this it became clear that fiber Bragg gratings provided a alternative for making the desired measurements and there was a shift of research focus on to include the photo-refractive properties of germano-silicate glasses used for most gratings and to the possibility of developing fiber laser sources for an integrated optical sensor in the research effort. During the course of this work several students from Christopher Newport University and other universities participated in this effort. Their names are listed below. Their participation was an important part of their education.

  8. Bluebonnet Fiber Collages

    ERIC Educational Resources Information Center

    Sterling, Joan

    2009-01-01

    This article presents a lesson that uses stitching and applique techniques to create a fiber collage in which every child is successful with high-quality work. This lesson was inspired by Tomie dePaola's "The Legend of the Bluebonnet." The back cover had a lovely illustration of the bluebonnet flower the author thought would translate easily to a…

  9. Optical Fiber Protection

    NASA Technical Reports Server (NTRS)

    1999-01-01

    F&S Inc. developed and commercialized fiber optic and microelectromechanical systems- (MEMS) based instrumentation for harsh environments encountered in the aerospace industry. The NASA SBIR programs have provided F&S the funds and the technology to develop ruggedized coatings and coating techniques that are applied during the optical fiber draw process. The F&S optical fiber fabrication facility and developed coating methods enable F&S to manufacture specialty optical fiber with custom designed refractive index profiles and protective or active coatings. F&S has demonstrated sputtered coatings using metals and ceramics and combinations of each, and has also developed techniques to apply thin coatings of specialized polyimides formulated at NASA Langley Research Center. With these capabilities, F&S has produced cost-effective, reliable instrumentation and sensors capable of withstanding temperatures up to 800? C and continues building commercial sales with corporate partners and private funding. More recently, F&S has adapted the same sensing platforms to provide the rapid detection and identification of chemical and biological agents

  10. Manufactured Textile Fibers

    NASA Astrophysics Data System (ADS)

    Gupta, Bhupender S.

    The first conversion of naturally occurring fibers into threads strong enough to be looped into snares, knit to form nets, or woven into fabrics is lost in prehistory. Unlike stone weapons, such threads, cords, and fabrics—being organic in nature—have in most part disappeared, although in some dry caves traces remain. There is ample evidence to indicate that spindles used to assist in the twisting of fibers together had been developed long before the dawn of recorded history. In that spinning process, fibers such as wool were drawn out of a loose mass, perhaps held in a distaff, and made parallel by human fingers. (A maidservant so spins in Giotto's The Annunciation to Anne, ca. A.D. 1306, Arena Chapel, Padua, Italy.1) A rod (spindle), hooked to the lengthening thread, was rotated so that the fibers while so held were twisted together to form additional thread. The finished length then was wound by hand around the spindle, which, in becoming the core on which the finished product was accumulated, served the dual role of twisting and storing, and, in so doing, established a principle still in use today.