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Sample records for accessory glass fiber

  1. Fracture resistance of weakened teeth restored using accessory glass fiber posts.

    PubMed

    da Rosa, Ricardo Abreu; Barreto, Mirela Sangoi; da Rosa, Tiago Abreu; Reis, Katia Rodrigues; Kaizer, Osvaldo Bazzan

    2013-01-01

    This study used differential root weakening to evaluate the fracture resistance of bovine teeth restored using glass fiber posts (with or without accessory glass fiber posts). Fifty bovine mandibular incisors were sectioned 14 mm from the apex, fixed in acrylic resin blocks, and divided into 5 groups: healthy roots with a glass fiber post (Group 1), partially weakened teeth with a glass fiber post (Group 2), partially weakened teeth with a glass fiber post and 2 accessory glass fiber posts (Group 3), extensively weakened teeth with a glass fiber post (Group 4), and extensively weakened teeth with a glass fiber post and 5 accessory glass fiber posts (Group 5). Posts were luted with resin cement, cores were prepared using composite resin, and metallic crowns were cemented. The specimens were stored in distilled water at 37°C for more than 72 hours until the fracture resistance test. Specimens were loaded at 135 degrees relative to the long axis of the tooth at a crosshead speed of 0.5 mm/minute in a universal testing machine. All groups predominantly exhibited favorable failure patterns and there were no statistically significant differences between groups (two-way ANOVA, α = 0.05). PMID:23454321

  2. Fracture resistance of structurally compromised premolar roots restored with single and accessory glass or quartz fiber posts

    PubMed Central

    Sharafeddin, Farahnaz; Alavi, Ali Asghar; Zare, Samira

    2014-01-01

    Background: Glass and quartz fiber posts are used in restoration of structurally compromised roots. Accessory fiber posts are recently introduced to enhance the fiber post adaptation. This study evaluated the effectiveness of glass versus quartz accessory fiber posts. Materials and Methods: In this experimental study, 40 mandibular premolar roots with similar dimension (radius of 3.5 ± 0.2 mm and length of 13 ± 0.5 mm) were selected and their root canals were flared until 1.5 mm of dentin wall remained. They were randomly assigned to four groups (n = 10) and restored as follows: Exacto glass fiber post (EX), Exacto glass fiber post + 2 Reforpin accessories (EXR), D. T. Light quartz fiber post (DT), and D. T. Light quartz fiber post + 2 Fibercone accessories (DTF). All posts were cemented with Duo-Link resin cement and the cores were built with the particulate filler composite. Following 1-week water storage, specimens were subjected to fracture loads in a universal testing machine. The maximum loads and failure modes were recorded and analyzed with the two-way analysis of variance (ANOVA) and Fisher's exact tests (α = 0.05). Results: The mean fracture resistance values (N) were 402.8 (EX), 378.4 (EXR), 400.1 (DT), and 348.5 (DTF). Two-way ANOVA test showed neither reinforcing method (P = 0.094), nor post composition (P = 0.462) had statistically significant differences on fracture resistance of the structurally compromised premolar teeth. Fisher's exact test also demonstrated no statistically significant difference regarding two variables (P = 0.695). Core fracture was the most common failure mode (62.5%). Conclusion: Glass and quartz fiber posts with or without accessories restored the weakened premolar roots equally. PMID:24932200

  3. 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.

  4. 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.

  5. 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.

  6. 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.

  7. Commercial and Experimental Glass Fibers

    NASA Astrophysics Data System (ADS)

    Wallenberger, Frederick T.

    Continuous glass fibers can be formed from melts with a wide range of compositions and viscosities. This chapter reviews pure silica fibers which are formed from highly viscous melts, silicate glass fibers with 50-70% SiO2 which are formed from moderately viscous melts, aluminate glass fibers with 50-80% Al2O3, as well as yttria-alumina-garnet (YAG) glass fibers which are formed from inviscid (literally non-viscous) melts. Commercial glass fibers are made for a variety of applications from pure silica rods and from silicate melts containing 50-70% SiO2 and 10-25% Al2O3. Boron-free, essentially boron-free, and borosilicate E-glass are general-purpose fibers. ERC-glass offers high corrosion resistance, HS-glass offers high-strength composites, D-glass offers a low dielectric constant, and A-glass offers the possibility of using waste container glass for less demanding applications.

  8. Apollo applications of beta fiber glass

    NASA Technical Reports Server (NTRS)

    Naimer, J.

    1971-01-01

    The physical characteristics of Beta fiber glass are discussed. The application of Beta fiber glass for fireproofing the interior of spacecraft compartments is described. Tests to determine the flammability of Beta fiber glass are presented. The application of Beta fiber glass for commercial purposes is examined.

  9. Safely splicing glass optical fibers

    NASA Technical Reports Server (NTRS)

    Korbelak, K.

    1980-01-01

    Field-repair technique fuses glass fibers in flammable environment. Apparatus consists of v-groove vacuum chucks on manipulators, high-voltage dc power supply and tungsten electrodes, microscope to observe joint alignment and fusion, means of test transmission through joint. Apparatus is enclosed in gas tight bos filled with inert gas during fusion. About 2 feet of fiber end are necessary for splicing.

  10. Fiber glass pulling. [in space

    NASA Technical Reports Server (NTRS)

    Workman, Gary L.

    1987-01-01

    Experiments were conducted to determine the viability of performing containerless glass fiber pulling in space. The optical transmission properties and glass-forming capabilities of the heavy metal fluorides are reviewed and the acoustic characteristics required for a molten glass levitation system are examined. The design limitations of, and necessary modifications to the acoustic levitation furnace used in the experiments are discussed in detail. Acoustic levitator force measurements were performed and a thermal map of the furnace was generated from thermocouple data. It was determined that the thermal capability of the furnace was inadequate to melt a glass sample in the center. The substitution of a 10 KW carbon monoxide laser for the original furnace heating elements resulted in improved melt heating.

  11. Containerless Manufacture of Glass Optical Fibers

    NASA Technical Reports Server (NTRS)

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

    1985-01-01

    Contamination and crystallization reduced in proposed process. Solid optical fiber drawn from an acoustically levitated lump of molten glass. New material added in solid form, melted and then moved into main body of molten glass. Single axis acoustic levitation furnances levitate glass melts at temperature up to about 700 degrees C. Processing in unit limited to low-melting temperature glasses.

  12. High-Strength Glass Fibers and Markets

    NASA Astrophysics Data System (ADS)

    Hausrath, Robert L.; Longobardo, Anthony V.

    High-strength glass fibers play a crucial role in composite applications requiring combinations of strength, modulus, and high-temperature stability. Compositions in the high-strength glass group include S-glass and R-glass, which are used for applications requiring physical properties that cannot be satisfied by conventional E-glass. Additional compositions are also available for specialized applications requiring extreme performance in any one area. The main competition for high-strength glasses in the marketplace comes from carbon and polymer fibers. Ultimately, the product of choice is based on a compromise between cost and performance and will vary depending on the application.

  13. Quantitative risk assessment of durable glass fibers.

    PubMed

    Fayerweather, William E; Eastes, Walter; Cereghini, Francesco; Hadley, John G

    2002-06-01

    This article presents a quantitative risk assessment for the theoretical lifetime cancer risk from the manufacture and use of relatively durable synthetic glass fibers. More specifically, we estimate levels of exposure to respirable fibers or fiberlike structures of E-glass and C-glass that, assuming a working lifetime exposure, pose a theoretical lifetime cancer risk of not more than 1 per 100,000. For comparability with other risk assessments we define these levels as nonsignificant exposures. Nonsignificant exposure levels are estimated from (a) the Institute of Occupational Medicine (IOM) chronic rat inhalation bioassay of durable E-glass microfibers, and (b) the Research Consulting Company (RCC) chronic inhalation bioassay of durable refractory ceramic fibers (RCF). Best estimates of nonsignificant E-glass exposure exceed 0.05-0.13 fibers (or shards) per cubic centimeter (cm3) when calculated from the multistage nonthreshold model. Best estimates of nonsignificant C-glass exposure exceed 0.27-0.6 fibers/cm3. Estimates of nonsignificant exposure increase markedly for E- and C-glass when non-linear models are applied and rapidly exceed 1 fiber/cm3. Controlling durable fiber exposures to an 8-h time-weighted average of 0.05 fibers/cm3 will assure that the additional theoretical lifetime risk from working lifetime exposures to these durable fibers or shards is kept below the 1 per 100,000 level. Measured airborne exposures to respirable, durable glass fibers (or shards) in glass fiber manufacturing and fabrication operations were compared with the nonsignificant exposure estimates described. Sampling results for B-sized respirable E-glass fibers at facilities that manufacture or fabricate small-diameter continuous-filament products, from those that manufacture respirable E-glass shards from PERG (process to efficiently recycle glass), from milled fiber operations, and from respirable C-glass shards from Flakeglass operations indicate very low median exposures of 0

  14. Fiber glass reinforced structural materials for aerospace application

    NASA Technical Reports Server (NTRS)

    Bartlett, D. H.

    1968-01-01

    Evaluation of fiber glass reinforced plastic materials concludes that fiber glass construction is lighter than aluminum alloy construction. Low thermal conductivity and strength makes the fiber glass material useful in cryogenic tank supports.

  15. High modulus high temperature glass fibers

    NASA Technical Reports Server (NTRS)

    Bacon, J. F.

    1973-01-01

    The search for a new high-modulus, high-temperature glass fiber involved the preparation of 500 glass compositions lying in 12 glass fields. These systems consisted primarily of low atomic number oxides and rare-earth oxides. Direct optical measurements of the kinetics of crystallization of the cordierite-rare earth system, for example, showed that the addition of rare-earth oxides decreased the rate of formation of cordierite crystals. Glass samples prepared from these systems proved that the rare-earth oxides made large specific contributions to the Young's modulus of the glasses. The best glasses have moduli greater than 21 million psi, the best glass fibers have moduli greater than 18 million psi, and the best glass fiber-epoxy resin composites have tensile strengths of 298,000 psi, compressive strengths of at least 220,000 psi, flexural strengths of 290,000 psi, and short-beam shear strengths of almost 17,000 psi.

  16. Dimensionally Stable Graphite-Fiber/Glass Composites

    NASA Technical Reports Server (NTRS)

    Harris, Robert; Bergen, George J.; Studer, Philip A.

    1992-01-01

    Method of making composites of glass matrices reinforced by graphite fibers provides for control of proportions, orientations, and distributions of fibers in matrices and for fused bonds between fibers and matrices. Enables fabrication of composites of high specific strength and dimensional stability. Method particularly suitable for making low-thermal-expansion platforms for optical instruments.

  17. Glass matrix composites. I - Graphite fiber reinforced glass

    NASA Technical Reports Server (NTRS)

    Prewo, K. M.; Bacon, J. F.

    1978-01-01

    An experimental program is described in which graphite fibers of Hercules HMS and HTS, Thornel 300, and Celanese DG-12 were used to reinforce, both uniaxially and biaxially, borosilicate pyrex glass. Composite flexural strength distribution, strength as a function of test temperature, fracture toughness and oxidative stability were determined and shown to be primarily a function of fiber type and the quality of fiber-matrix bond formed during composite fabrication. It is demonstrated that the graphite fiber reinforced glass system offers unique possibilities as a high performance structural material.

  18. Inert strength of pristine silica glass fibers

    SciTech Connect

    Smith, W.L.; Michalske, T.A.

    1993-11-01

    Silica glass fibers have been produced and tested under ultra high vacuum (UHV) conditions to investigate the inert strength of pristine fibers in absence of reactive agents. Analysis of the coefficient of variation in diameter ({upsilon}{sub d}) vs the coefficient of variation of breaking strength ({upsilon}{sub {sigma}}) does not adequately explain the variation of breaking stress. Distribution of fiber tensile strength data suggests that the inert strength of such fibers is not single valued and that the intrinsic strength is controlled by defects in the glass. Furthermore, comparison of room temperature UHV data with LN{sub 2} data indicates that these intrinsic strengths are not temperature dependent.

  19. Design of Energy-Friendly Glass Fibers

    NASA Astrophysics Data System (ADS)

    Wallenberger, Frederick T.

    Incumbent fiberglass compositions rely on decades of commercial experience. From a compositional point of view, many of these melts require more energy than needed in their production, or emit toxic effluents into the environment. This chapter reviews the design of energy- and/or environmentally friendly E-glass, HT-glass, ECR-glass, A-glass, and C-glass compositions, which have lower viscosities or fiber-forming temperatures and therefore require less energy in a commercial furnace than the respective incumbent compositions and/or do not contain ingredients which are of environmental concern.

  20. Blowable glass fiber thermal insulation product

    SciTech Connect

    Spittle, K.S.

    1984-10-09

    A process and apparatus for manufacturing a blowable glass fiber insulation product is disclosed. The product resulting from the process and apparatus is also disclosed. This process includes the steps of cutting unbonded glass fiber matting and lengths of twisted glass fiber yarn raw material into predetermined relatively large size pieces. The pieces are mixed together and the mixture is fluffed to decrease its density. The mixture is then hammermilled into relatively smaller size pieces suitable for use as blowable insulation. In accordance with the apparatus according to this invention, a cutter cuts glass fiber matting and lengths of twisted glass fiber yarn into relatively large size pieces which are mixed and then fluffed and further cut in a fluffer. A hammermill is used for reducing the mixture into relatively smaller size pieces suitable for use as blowable insulation. The blowable insulation product comprises loose, irregularly formed and separate clumps of glass fiber material approximately one inch (215 cm.) in diameter and having a density of 1 lb./cu./ft. (16 kg./cu./m.) and has a thermal resistance value of 3.3 per inch (2.5 cm.) of thickness.

  1. New glass developments for fiber optics

    NASA Astrophysics Data System (ADS)

    Higby, Paige L.; Holst, Karen; Tabor, Kevin; James, William; Chase, Elizabeth; Pucilowski, Sally; Gober-Mangan, Elizabeth; Klimek, Ronald; Karetta, Frank; Schreder, Bianca

    2014-02-01

    Fiber optic components for lighting and imaging applications have been in use for decades. Recent requirements such as a need for RoHS compliance, attractive market pricing, or particular optical properties, such as numerical aperture (NA) or transmission, have required SCHOTT to develop and implement new glasses for these applications. From Puravis™ lead-free fibers for lighting applications, to new glasses for digital X-ray imaging and sensor applications, the challenges for SCHOTT scientists are considerable. Pertinent properties of these glasses and methods of determination for suitability will be discussed.

  2. Multicomponent glass fiber optic integrated structures

    NASA Astrophysics Data System (ADS)

    Pysz, Dariusz; Kujawa, Ireneusz; Szarniak, Przemyslaw; Franczyk, Marcin; Stepien, Ryszard; Buczynski, Ryszard

    2005-09-01

    A range of integrated fiber optic structures - lightguides, image guides, multicapillary arrays, microstructured (photonic) fibers - manufactured in the Institute of Electronic Materials Technology (ITME) is described. All these structures are made of multicomponent glasses (a part of them melted in ITME). They can be manufactured in similar multistep process that involves drawing glass or lightguide rods and tubes preparing glass performs, stacking a bundle with rods and (or) tubes, drawing multifiber or multicapillary performs. Structure formation, technological process, characterization and applications of different integrated structures are presented.

  3. Scintillating glass fiber-optic neutron sensors

    NASA Astrophysics Data System (ADS)

    Abel, K. H.; Arthur, R. J.; Bliss, M.

    1994-04-01

    Pacific Northwest Laboratory (PNL) has fabricated cerium-activated lithium silicate scintillating fibers via a hot-downdraw process. These fibers, which, as produced, typically have a transmission length (e(sup -1) length) of greater than 2 meters, are found to undergo aging when subjected to room air. The aging, which is complete in a few weeks, reduces the transmission length to the order of 0.5 meter. Because of the high alkali content of the glass (on the order of 20-30 mole percent lithia), we have attributed this aging to aqueous corrosion at the polymer cladding/glass interface. Changes in transmission with chemical treatment of the surface support the corrosion model. Fiber transmission performance has been preserved by modifying the hot-downdraw to a double crucible to produce glass-on-glass waveguides.

  4. In vitro evaluation of glass fiber post

    PubMed Central

    Sharma, Navneet; Singh, Harpal

    2012-01-01

    Statement of problem: Techniques and recommendations for the restoration of endodontically treated teeth have changed from the use of custom cast metal post and core system to glass fiber-reinforced (GFRC) post and composite core system. Has this latest prefabricated glass fiber reinforced post and composite core system increased the fracture resistance of teeth and reduced the incidence of unrestorable root fractures. Purpose: The purpose of this study was to evaluate the incidence of root fracture and mode of failure of endodontically treated teeth restored with two different post and core systems. Material and Methods: Forty maxillary central incisors were randomly divided into two groups. (n=20). All teeth received endodontic treatment. First group was restored with custom cast post and core system. Second group was restored with glass fiber post and composite core system. In Both the groups posts were cemented with adhesive resin cement. Compressive load was applied at an angle of 130 to the long axis of teeth at a cross head speed of 1 mm/min until fracture occurred. Data were analyzed with student “t” test P<.001. Results: The mean value for fracture resistance was (331.4025) N in Group -I Custom cast Ni-Cr post and core and (237.0625) N in Group -II Glass fiber reinforced post and composite core system. Students “t” test shows the significant difference in fracture resistance of two groups. Conclusion: This study showed that the incidence of root fracture was significantly higher in custom cast Ni-Cr post and core system than glass fiber post and composite core system. A more favourable mode of failure was observed in teeth restored with Group II glass fiber post system. Key words:Post-and-core technique, glass fiber post, cast post and-core system, fracture resistance, endodontically treated teeth. PMID:24558556

  5. Scintillating-glass-fiber neutron sensors

    NASA Astrophysics Data System (ADS)

    Abel, K. H.; Arthur, R. J.; Bliss, M.; Brite, D. W.; Brodzinski, R. L.; Craig, R. A.; Geelhood, B. D.; Goldman, D. S.; Griffin, J. W.; Perkins, R. W.; Reeder, P. L.; Richey, W. R.; Stahl, K. A.; Sunberg, D. S.; Warner, R. A.; Wogman, N. A.; Weber, M. J.

    1994-12-01

    Cerium-doped lithium-silicate glass fibers have been developed at Pacific Northwest Laboratory (PNL) for use as thermal neutron detectors. By using highly-enriched 6Li, these fibers efficiently capture thermal neutrons and produce scintillation light that can be detected at the ends of the fibers. Advantages of scintillating fibers over 3He or BF 3 proportional tubes include flexibility in geometric configuration, ruggedness in high-vibration environments, and less detector weight for the same neutron sensitivity. This paper describes the performance of these scintillating fibers with regard to count rates, pulse height spectra, absolute efficiencies, and neutron/gamma discrimination. Fibers with light transmission lengths ( {1}/{e}) of greater than 2 m have been produced at PNL. Neutron sensors in fiber form allow development of a variety of neutron detectors packaged in previously unavailable configurations. Brief descriptions of some of the devices already produced are included to illustrate these possibilities.

  6. Single mode glass fiber welding

    NASA Technical Reports Server (NTRS)

    Nelson, M. D.; Fearnehough, H. T.; Goldstein, R.; Goss, W. C.

    1979-01-01

    The electric-arc welding of commercially available single-mode optical fiber has been demonstrated. A mean transmission of 92% and a maximum transmission of 98% are reported for welds of fiber waveguide of 4.5 microns core diameter.

  7. Single-mode fluorotellurite glass fiber

    NASA Astrophysics Data System (ADS)

    Zhan, Huan; Huang, Zhihua; Wen, Jing; Jiang, Lei; Wang, Jianjun; Jing, Feng; Lin, Aoxiang

    2016-03-01

    By multi-stage rod-in-tube fiber drawing process, a single-mode fluorotellurite glass fiber was fabricated and reported for the first time. Benefiting from chemical-physical dehydration process to remove water and OH- groups, the propagation loss was decreased to 1.9 dB/m at 1550 nm and the infrared window is extended from 2.8 μm to 4.2 μm, i.e. a new kind of mid-infrared glass fiber. The fiber is with a small core of 3.52 μm in diameter to meet single-mode condition, and the effective nonlinear parameter γ was estimated to be 236.7 W-1 km-1 at 1550 nm by using continuous-wave self-phase modulation method.

  8. Single-mode fluorotellurite glass fiber

    NASA Astrophysics Data System (ADS)

    Zhan, Huan; Huang, Zhihua; Wen, Jing; Jiang, Lei; Wang, Jianjun; Jing, Feng; Lin, Aoxiang

    2016-03-01

    By multi-stage rod-in-tube fiber drawing process, a single-mode fluorotellurite glass fiber was fabricated and reported for the first time. Benefiting from chemical-physical dehydration process to remove water and OH- groups, the propagation loss was decreased to 1.9 dB/m at 1550 nm and the infrared window is extended from 2.8 μm to 4.2 μm, i.e. a new kind of mid-infrared glass fiber. The fiber is with a small core of 3.52 μm in diameter to meet single-mode condition, and the effective nonlinear parameter γ was estimated to be 236.7 W-1 km-1 at 1550 nm by using continuous-wave self-phase modulation method. © 2015 Elsevier B.V.

  9. Development of new radiopaque glass fiber posts.

    PubMed

    Furtos, Gabriel; Baldea, Bogdan; Silaghi-Dumitrescu, Laura

    2016-02-01

    The aim of this study was to analyze the radiopacity and filler content of three experimental glass fiber posts (EGFP) in comparison with other glass/carbon fibers and metal posts from the dental market. Three EGFP were obtained by pultrusion of glass fibers in a polymer matrix based on 2,2-bis[4-(2-hydroxy-3-methacryloyloxypropoxy)-phenyl]propane (bis-GMA) and triethyleneglycol dimethacrylate (TEGDMA) monomers. Using intraoral sensor disks 27 posts, as well as mesiodistal sections of human molar and aluminum step wedges were radiographed for evaluation of radiopacity. The percentage compositions of fillers by weight and volume were investigated by combustion analysis. Two EGFP showed radiopacity higher than enamel. The commercial endodontic posts showed radiopacity as follows: higher than enamel, between enamel and dentin, and lower than dentin. The results showed statistically significant differences (p b 0.05)when evaluatedwith one-way ANOVA statistical analysis. According to combustion analyses, the filler content of the tested posts ranges between 58.84wt.% and 86.02wt.%. The filler content of the tested EGFP ranged between 68.91 wt.% and 79.04 wt.%. EGFP could be an alternative to commercial glass fiber posts. Futureglass fiber posts are recommended to present higher radiopacity than dentin and perhaps ideally similar to or higher than that of enamel, for improved clinical detection. The posts with a lower radiopacity than dentin should be considered insufficiently radiopaque. The radiopacity of some glass fiber posts is not greatly influenced by the amount of filler. PMID:26652441

  10. Fluoride glass fibers: applications and prospects

    NASA Astrophysics Data System (ADS)

    Poulain, Marcel

    1998-09-01

    Fluoride glass fibers have been intensively developed for the last 20 years. A major effort was devoted to the fabrication of low loss fibers for repeaterless long haul telecommunications. This step which ended in the late eighties provided the basic technology for the manufacturing of multimode and single mode fibers with minimum losses below 10 dB/km. Such fibers area now used for various passive applications requiring the handling of IR signal. In this respect, fluoride fibers are complementary to silica fibers when wavelength exceeds 2 micrometers . Some practical set ups are operating for IR imaging, remote spectroscopy and thermometry. Special fibers such as polarization maintaining fibers have been developed for interferometric astronomy, which could also apply to sensors. UV transmission has still to be developed. Laser power delivery is another field of application for these fibers. YAG:Er laser at 2.9 micrometers attracts a growing interest for medical applications, ophthalmology and dentistry, while prospects for CO laser are positive. Active fibers are based on rare earth doped single mode fibers. They lead to the definition of numerous new laser lines and emphasized the potential of up conversion for the generation of visible light using IR pumping laser diodes. High power output has been achieved in the blue and the red light, which open prospects for compact and all solid state fiber lasers for a wide range of applications, from displays to medical uses. Optical amplification makes another field of R and D centered on telecommunication needs. Pr3+ doped fluoride fibers have been used for the 1.3 micrometers band, and Er based fluoride fiber amplifiers exhibit wider and flatter gain than those made from silica. Optical amplification may be implemented at other wavelengths for more general purposes.

  11. Natural Fiber or Glass Reinforced Polypropylene Composites?

    NASA Astrophysics Data System (ADS)

    Lorenzi, W.; Di Landro, L.; Casiraghi, A.; Pagano, M. R.

    2008-08-01

    Problems related to the recycle of conventional composite materials are becoming always more relevant for many industrial fields. Natural fiber composites (NFC) have recently gained much attention due to their low cost, environmental gains (eco-compatibility), easy disposal, reduction in volatile organic emissions, and their potential to compete with glass fiber composites (GFC). Interest in natural fibers is not only based over ecological aspects. NFC have good mechanical performances in relation to their low specific weight and low price. A characterization of mechanical properties, dynamic behavior, and moisture absorption is presented.

  12. NATURAL FIBER OR GLASS REINFORCED POLYPROPYLENE COMPOSITES?

    SciTech Connect

    Lorenzi, W.; Di Landro, L.; Casiraghi, A.; Pagano, M. R.

    2008-08-28

    Problems related to the recycle of conventional composite materials are becoming always more relevant for many industrial fields. Natural fiber composites (NFC) have recently gained much attention due to their low cost, environmental gains (eco-compatibility), easy disposal, reduction in volatile organic emissions, and their potential to compete with glass fiber composites (GFC). Interest in natural fibers is not only based over ecological aspects. NFC have good mechanical performances in relation to their low specific weight and low price. A characterization of mechanical properties, dynamic behavior, and moisture absorption is presented.

  13. Airborne Laboratory Apparatus Draws Glass Fibers

    NASA Technical Reports Server (NTRS)

    Tucker, Dennis S.; Smith, Guy A.

    1993-01-01

    Glass-fiber-drawing apparatus designed for studies of effect of gravitation on drawing process. Clear plastic housing surrounds fiber-drawing equipment and some of associated electronic instrumentation. External rack holds video monitor, personal computer, keyboard, videotape recorder, and power switch panel. Mounted in research aircraft, apparatus makes continuous video recordings of formation of fiber at effective gravitational accelerations ranging from 0.001 to 2 times normal Earth gravitational acceleration as aircraft dives, then pulls out of dives. Also records pertinent process data on video image.

  14. Nonwoven glass fiber mat reinforces polyurethane adhesive

    NASA Technical Reports Server (NTRS)

    Roseland, L. M.

    1967-01-01

    Nonwoven glass fiber mat reinforces the adhesive properties of a polyurethane adhesive that fastens hardware to exterior surfaces of aluminum tanks. The mat is embedded in the uncured adhesive. It ensures good control of the bond line and increases the peel strength.

  15. Making Glass-Fiber-Reinforced Coolant Tubes

    NASA Technical Reports Server (NTRS)

    Curtin, F.

    1985-01-01

    New use found for heat-shrinkable sleeves. Smooth, noncontaminating channels for transporting cooling water in Space Shuttle Extravehicularmobility unit made of fiberglass tubing with aid of heat-shrinkable sleeves. Previously, glass fibers from inner walls of tubes contaminate water.

  16. Glass-clad semiconductor core optical fibers

    NASA Astrophysics Data System (ADS)

    Morris, Stephanie Lynn

    Glass-clad optical fibers comprising a crystalline semiconductor core have garnered considerable recent attention for their potential utility as novel waveguides for applications in nonlinear optics, sensing, power delivery, and biomedicine. As research into these fibers has progressed, it has become evident that excessive losses are limiting performance and so greater understanding of the underlying materials science, coupled with advances in fiber processing, is needed. More specifically, the semiconductor core fibers possess three performance-limiting characteristics that need to be addressed: (a) thermal expansion mismatches between crystalline core and glass cladding that lead to cracks, (b) the precipitation of oxide species in the core upon fiber cooling, which results from partial dissolution of the cladding glass by the core melt, and (c) polycrystallinity; all of which lead to scattering and increased transmission losses. This dissertation systematically studies each of these effects and develops both a fundamental scientific understanding of and practical engineering methods for reducing their impact. With respect to the thermal expansion mismatch and, in part, the dissolution of oxides, for the first time to our knowledge, oxide and non-oxide glass compositions are developed for a series of semiconductor cores based on two main design criteria: (1) matching the thermal expansion coefficient between semiconductor core and glass cladding to minimize cracking and (2) matching the viscosity-temperature dependences, such that the cladding glass draws into fiber at a temperature slightly above the melting point of the semiconductor in order to minimize dissolution and improve the fiber draw process. The x[Na 2O:Al2O3] + (100 - 2x)SiO2 glass compositional family was selected due to the ability to tailor the glass properties to match the aforementioned targets through slight variations in composition and adjusting the ratios of bridging and non-bridging oxygen

  17. Heavy metal fluoride glass fibers and their applications

    NASA Astrophysics Data System (ADS)

    Saad, Mohammed

    2011-12-01

    The availability of high quality optical fibers with transmission window, larger than that of silica fiber, extends the use of optical fibers and open new application fields. There is increasing demand of optical fiber with transmission over 2 microns, where silica is opaque, for applications as diverse as sensing, fiber lasers and amplifiers, defense (IRCM), spectroscopy... No materials can fulfill all applications needs. Engineers have to make some compromise when choosing the right materials for the right application. Heavy metal fluoride glass is one of these materials. The glass, under bulk form, has a wide transmission window from 0.3 up to 8 microns, without any absorption peaks. Heavy metal fluoride glass fibers are drawn using the preform technique, the same technique used for silica fiber. This technique has proven to allow good control of fiber dimensions and geometry. Fluoride glass fibers with different exotics shapes have already been obtained, such as D-shaped, square, of centered fiber, multi cladding fibers and microstructured fibers.... As far as active fibers are concerned, heavy metal fluoride glasses have low phonon energy and can contain high concentration of active ions, rare-earth elements. Therefore, new laser lines have been already demonstrated using fluoride glass fibers. Fiber lasers with output power exceeding 10 w have been obtained by different groups. This paper will present the latest development of fluoride glass fiber technology, including fibers optical and mechanical properties, fiber lasers and power handling.

  18. Photonic crystal fibers based on chalcogenide glasses

    NASA Astrophysics Data System (ADS)

    Adam, J. L.; Troles, J.; Brilland, L.; Coulombier, Q.; Chartier, T.

    2010-10-01

    Chalcogenide glasses are known for their large transparency in the mid-infrared and their high refractive index (>2). They present also a high non-linear coefficient (n2), 100 to 1000 times larger than for silica, depending on the composition. An original way to obtain single-mode fibers is to design microstructured optical fibers (MOFs). These fibers present unique optical properties thanks to the high degree of freedom in the design of their geometrical structure. A classical method to realize MOFs is the stack-and-draw technique. However, with chalcogenide glasses, that technique induces optical losses at the interfaces in the stack of capillaries. In consequence, we have developed a new casting method to fabricate the chalcogenide preform. This method permits to obtain optical losses around 1 dB/m at 1.55 μm and 0.3 dB/m in the mid-IR region. Various chalcogenide microstructured fibers working in the IR range were prepared in order to take advantage of the non-linear properties of these glasses and of the original MOF properties. For example, fibers with small effective mode area (Aeff < 10 μm2) have been realized to exacerbate the non-linear optical properties. Such fibers will find applications for signal regeneration in telecom, and for the generation of supercontinuum sources. On the contrary, for military applications in the 3-5 and 8-12 μm windows, large effective mode area and single mode fibers have been designed to permit the propagation of high-power gaussian laser beams.

  19. Glass fiber manufacturing and fiber safety: the producer's perspective.

    PubMed Central

    Bender, J R; Hadley, J G

    1994-01-01

    Historically, the potential health effects of airborne fibers have been associated with the dose, dimension, and durability. Increasing focus is being placed on the latter category. Concern about airborne fiber safety could be reduced by manufacturing fibers that are not respirable; however, due to performance and manufacturing constraints on glasswool insulations, this is not possible today. These products are an important part of today's economy and as a major manufacturer, Owens-Corning is committed to producing and marketing materials that are both safe and effective in their intended use. To this end, manufacturing technology seeks to produce materials that generate low concentrations of airborne fibers, thus minimizing exposure and irritation. The range of fiber diameters is controlled to assure effective product performance and, as far as possible, to minimize respirability. Glass compositions are designed to allow effective fiber forming and ultimate product function. Fiber dissolution is primarily a function of composition; this too, can be controlled within certain constraints. Coupled with these broad parameters is an extensive product stewardship program to assure the safety of these materials. This article will discuss the factors that influence glasswool insulation production, use, and safety. PMID:7882953

  20. FIBER LENGTH DISTRIBUTION MEASUREMENT FOR LONG GLASS AND CARBON FIBER REINFORCED INJECTION MOLDED THERMOPLASTICS

    SciTech Connect

    Kunc, Vlastimil; Frame, Barbara J; Nguyen, Ba N.; TuckerIII, Charles L.; Velez-Garcia, Gregorio

    2007-01-01

    Procedures for fiber length distribution (FLD) measurement of long fiber reinforced injection molded thermoplastics were refined for glass and carbon fibers. Techniques for sample selection, fiber separation, digitization and length measurement for both fiber types are described in detail. Quantitative FLD results are provided for glass and carbon reinforced polypropylene samples molded with a nominal original fiber length of 12.7 mm (1/2 in.) using equipment optimized for molding short fiber reinforced thermoplastics.

  1. Modelling of the glass fiber length and the glass fiber length distribution in the compounding of short glass fiber-reinforced thermoplastics

    NASA Astrophysics Data System (ADS)

    Kloke, P.; Herken, T.; Schöppner, V.; Rudloff, J.; Kretschmer, K.; Heidemeyer, P.; Bastian, M.; Walther, Dridger, A.

    2014-05-01

    The use of short glass fiber-reinforced thermoplastics for the production of highly stressed parts in the plastics processing industry has experienced an enormous boom in the last few years. The reasons for this are primarily the improvements to the stiffness and strength properties brought about by fiber reinforcement. These positive characteristics of glass fiber-reinforced polymers are governed predominantly by the mean glass fiber length and the glass fiber length distribution. It is not enough to describe the properties of a plastics component solely as a function of the mean glass fiber length [1]. For this reason, a mathematical-physical model has been developed for describing the glass fiber length distribution in compounding. With this model, it is possible on the one hand to optimize processes for the production of short glass fiber-reinforced thermoplastics, and, on the other, to obtain information on the final distribution, on the basis of which much more detailed statements can be made about the subsequent properties of the molded part. Based on experimental tests, it was shown that this model is able to accurately describe the change in glass fiber length distribution in compounding.

  2. Glass fiber addition strengthens low-density ablative compositions

    NASA Technical Reports Server (NTRS)

    Chandler, H. H.

    1974-01-01

    Approximately 15% of E-glass fibers was added to compositions under test and greatly improved char stability. Use of these fibers also reduced thermal strains which, in turn, minimized char shrinkage and associated cracks, subsurface voids, and disbonds. Increased strength allows honeycomb core reinforcement to be replaced by equivalent amount of glass fibers.

  3. Interactions between the glass fiber coating and oxidized carbon nanotubes

    NASA Astrophysics Data System (ADS)

    Ku-Herrera, J. J.; Avilés, F.; Nistal, A.; Cauich-Rodríguez, J. V.; Rubio, F.; Rubio, J.; Bartolo-Pérez, P.

    2015-03-01

    Chemically oxidized multiwall carbon nanotubes (MWCNTs) were deposited onto commercial E-glass fibers using a dipping procedure assisted by ultrasonic dispersion. In order to investigate the role of the fiber coating (known as "sizing"), MWCNTs were deposited on the surface of as-received E-glass fibers preserving the proprietary coating as well as onto glass fibers which had the coating deliberately removed. Scanning electron microscopy and Raman spectroscopy were used to assess the distribution of MWCNTs onto the fibers. A rather homogeneous coverage with high density of MWCNTs onto the glass fibers is achieved when the fiber coating is maintained. Fourier transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS) and nuclear magnetic resonance (NMR) analyses of the chemical composition of the glass fiber coating suggest that such coating is a complex mixture with multiple oxygen-containing functional groups such as hydroxyl, carbonyl and epoxy. FTIR and XPS of MWCNTs over the glass fibers and of a mixture of MWCNTs and fiber coating provided evidence that the hydroxyl and carboxyl groups of the oxidized MWCNTs react with the oxygen-containing functional groups of the glass fiber coating, forming hydrogen bonding and through epoxy ring opening. Hydrogen bonding and ester formation between the functional groups of the MWCNTs and the silane contained in the coating are also possible.

  4. Fire Survivability Of Glass Optical Fibers

    NASA Astrophysics Data System (ADS)

    Hefty, Robert W.

    1990-01-01

    Samples of a 140/100-micron single-fiber optical cable* were tested in a flame environment to determine 1) the effectiveness of Nextel 312** ceramic-fiber sleeving for providing thermal protection to the cable and 2) the effects upon light-signal transmission. The optical cables were tested with and without the protective sleeve (or jacket) in a standard 6-inch diameter propane burner i'2 at flame temperatures ranging from approximately 450° to 860°C (842° to 1580°F). The flame tests were conducted with and without external vibration being applied. During a 30-minute test run of a jacketed cable at a nominal flame temperature of 500°C (932°F) without external vibration applied, the optical intensity (-15 dbm) of the signal passing through the fiber was essentially unchanged, and the signal was uninterrupted. In addition, the shape of the 1-megahertz square-wave output signal was unchanged, as observed on an oscillope. The same test specimen was re-tested for another 30-minute period without vibration at a higher nominal temperature of 735°C (1355°F). During this second run, the output signal was again received continuously without decrease in optical intensity or distortion of the square-wave shape. However, the signal was finally lost due to mechanical failure of the single optical fiber when the specimen holder was removed from the burner after the second run. When the ceramic sleeving was cut open along its length, inspection showed that all of the plastic materials used in the cable construction had completely burned and decomposed. Except for a small amount of white ash, only broken pieces of the glass fiber were found inside the ceramic sleeve. It became evident that the glass fiber alone had survived throughout two 30-minute flame-test runs and was able to pass the signal without interruption or loss of intensity. The results of other test runs are discussed, in which optical cable samples were tested with and without protective sleeving, and with

  5. Crack initiation in borosilicate glass-SiC fiber composites

    SciTech Connect

    Dutton, R.E.; Pagano, N.J.; Kim, R.Y.

    1996-04-01

    The initiation of matrix microcracking was investigated in unidirectional glass matrix composites having controlled fiber spacing. Observations were taken from composites consisting of regular arrays of TiB{sub 2}-coated SIGMA 1240 and carbon-coated SCS-6 monofilament SiC fibers in a series of borosilicate glasses. The thermal expansion mismatch between the fibers and glass matrix was varied such that the resulting radial stresses after processing ranged from tensile to compressive. The glass strongly bonds to the TiB{sub 2}-coated SIGMA 1240 fiber but weakly bonds to the carbon coating of the SCS-6 fiber, allowing the investigation of the effects of bonding at the fiber/matrix interface. The observed crack initiation stresses of the various composites are compared to predictions based on a previously developed semiempirical model and used to study the influence of the volume fraction of fibers, residual stress state and interface strength.

  6. Ultraflat supercontinuum generation in soft-glass photonic crystal fibers

    NASA Astrophysics Data System (ADS)

    Miret, J. J.; Silvestre, E.; Andrés, P.

    2009-05-01

    We recognize some photonic-crystal-fiber structures, made up of soft glass, that generate ultrawide (over an octave), very smooth and highly coherent supercontinuum spectrum when illuminated with femtosecond pulsed light around 1.55 μm. The design of soft-glass microstructured fiber geometry with nearly ultraflattened, positive and low dispersion is crucial to accomplish the above goals.

  7. Interface reaction of optical glass fiber sintered with low-temperature sealing glass

    NASA Astrophysics Data System (ADS)

    Xu, Bo; Liu, Guoying; Zu, Chengkui; Gao, Xiping; Han, Bin; Zhu, Baojing; Yin, Xianyin

    2014-12-01

    Low-temperature sealing glass (320-380°C) can be applied to the hermetic package of optical fiber devices, without the need of metallization. This paper introduced a PbO-ZnO-B2O3-F system low-temperature glass composite which has an softening point as low as 246°C and expansion coefficient of 8.0 ppm/°C. The glass composite was sealed with quartz glass fibers at 360-390°C, then the effect of sintering temperature and holding time on the surface reaction were well investigated. Although the mismatch of expansion coefficient exists within glass fiber, negative expansion filler and parent glass, they combined well with each other after a short time heating. The F- in glass network helped to lower the sealing temperature, wet the oxide surface and promote the combination of parent glass and fibers. The sealing temperature and holding time affect the interface layer and the shape of the fiber. The optimum packaging process should be sealing composite glass and fibers beneath 380°C with shortened holding time as possible. Using glazed glass composite preforms, sealing fiber in a ferrule to achieve compressed package will be helpful to realize hermetic package for optical fiber devices.

  8. Phosphate-based glass fiber vs. bulk glass: Change in fiber optical response to probe in vitro glass reactivity.

    PubMed

    Massera, J; Ahmed, I; Petit, L; Aallos, V; Hupa, L

    2014-04-01

    This paper investigates the effect of fiber drawing on the thermal and structural properties as well as on the glass reactivity of a phosphate glass in tris(hydroxymethyl)aminomethane-buffered (TRIS) solution and simulated body fluid (SBF). The changes induced in the thermal properties suggest that the fiber drawing process leads to a weakening and probable re-orientation of the POP bonds. Whereas the fiber drawing did not significantly impact the release of P and Ca, an increase in the release of Na into the solution was noticed. This was probably due to small structural reorientations occurring during the fiber drawing process and to a slight diffusion of Na to the fiber surface. Both the powders from the bulk and the glass fibers formed a Ca-P surface layer when immersed in SBF and TRIS. The layer thickness was higher in the calcium and phosphate supersaturated SBF than in TRIS. This paper for the first time presents the in vitro reactivity and optical response of a phosphate-based bioactive glass (PBG) fiber when immersed in SBF. The light intensity remained constant for the first 48h after which a decrease with three distinct slopes was observed: the first decrease between 48 and 200h of immersion could be correlated to the formation of the Ca-P layer at the fiber surface. After this a faster decrease in light transmission was observed from 200 to ~425h in SBF. SEM analysis suggested that after 200h, the surface of the fiber was fully covered by a thin Ca-P layer which is likely to scatter light. For immersion times longer than ~425h, the thickness of the Ca-P layer increased and thus acted as a barrier to the dissolution process limiting further reduction in light transmission. The tracking of light transmission through the PBG fiber allowed monitoring of the fiber dissolution in vitro. These results are essential in developing new bioactive fiber sensors that can be used to monitor bioresponse in situ. PMID:24582246

  9. Anomalous rheological behavior of long glass fiber reinforced polypropylene

    NASA Astrophysics Data System (ADS)

    Kim, Dong Hak; Lee, Young Sil; Son, Younggon

    2012-12-01

    Dynamic rheological properties of PP-based long glass fiber-reinforced thermoplastics (LFT) were investigated. Weight fractions of the glass fibers investigated in the present study ranged from 0.15 to 0.5, which are higher than those of previous studies. We observed very abnormal rheological behavior. Complex viscosity (η*) of the LFT increased with the glass fiber content up to 40 wt. %. However, the η* with a weight fraction of 0.5 is observed to be lower than that of LFT with a weight fraction of 0.4 in spite of higher glass fiber content. From various experiments, we found that this abnormal behavior is analogous to the rheological behavior of a lyotropic liquid crystalline polymer solution and concluded that the abnormal rheological behavior for the LFT is attributed to the formation of a liquid crystal- like structure at high concentrations of long glass fibers.

  10. Preparation of chalcogenide glass fiber using an improved extrusion method

    NASA Astrophysics Data System (ADS)

    Jiang, Chen; Wang, Xunsi; Zhu, Minming; Xu, Huijuan; Nie, Qiuhua; Dai, Shixun; Tao, Guangming; Shen, Xiang; Cheng, Ci; Zhu, Qingde; Liao, Fangxing; Zhang, Peiquan; Zhang, Peiqing; Liu, Zijun; Zhang, Xianghua

    2016-05-01

    We developed the extrusion method to prepare arsenic-free chalcogenide glass fibers with glass cladding. By using the double nested extrusion molds and the corresponding isolated stacked extrusion method, the utilization rate of glass materials was greatly improved compared with the conventional extrusion method. Fiber preforms with optimal stability of core/cladding ratio throughout the 160 mm length were prepared using the developed extrusion method. Typical fiber structure defects between the core/cladding interface, such as bubbles, cracks, and core diameter variation, were effectively eliminated. Ge-Sb-Se/S chalcogenide glasses were used to form a core/cladding pair and fibers with core/cladding structure were prepared by thermally drawing the extruded preforms. The transmission loss, fiber bending loss, and other optical characters of the fibers were also investigated.

  11. Apparatus For Making Glass Fibers Without The Aid Of Gravity

    NASA Technical Reports Server (NTRS)

    Tucker, Dennis; Smith, Guy A.; Workman, Gary

    1995-01-01

    Report describes apparatus for making optical fibers in microgravity. Includes sting that makes initial contact with softened glass to start drawing fiber. Absence of gravity helps to suppress nucleation of crystallites, which increase scattering of light and thus reduce transmission of light along fiber.

  12. Fiber reinforced glasses and glass-ceramics for high performance applications

    NASA Technical Reports Server (NTRS)

    Prewo, K. M.; Brennan, J. J.; Layden, G. K.

    1986-01-01

    The development of fiber reinforced glass and glass-ceramic matrix composites is described. The general concepts involved in composite fabrication and resultant composite properties are given for a broad range of fiber and matrix combinations. It is shown that composite materials can be tailored to achieve high levels of toughness, strength, and elastic stiffness, as well as wear resistance and dimensional stability.

  13. Fracture behavior of glass fiber reinforced polymer composite

    SciTech Connect

    Avci, A.; Arikan, H.; Akdemir, A

    2004-03-01

    Chopped strand glass fiber reinforced particle-filled polymer composite beams with varying notch-to-depth ratios and different volume fractions of glass fibers were investigated in Mode I fracture using three-point bending tests. Effects of polyester resin content and glass fiber content on fracture behavior was also studied. Polyester resin contents were used 13.00%%, 14.75%, 16.50%, 18.00% and 19.50%, and glass fiber contents were 1% and 1.5% of the total weight of the polymer composite system. Flexural strength of the polymer composite increases with increase in polyester and fiber content. The critical stress intensity factor was determined by using several methods such as initial notch depth method, compliance method and J-integral method. The values of K{sub IC} obtained from these methods were compared.

  14. Neutron-sensing scintillating glass optical fiber detectors

    SciTech Connect

    Bliss, M.; Reeder, P.L.; Craig, R.A.

    1994-07-01

    Pacific Northwest Laboratory (PNL) has developed and tested the highest-transmission neutron-sensing glass fibers reported in the open literature to date. By developing glass compositions specifically for fiber drawing and by using superior oxidationstate controls and rapid quenching, PNL produces, fiber with useful lengths in excess of 200 cm. These long fibers can be used in detectors. Test results on the fibers used as a form-fitting detector around a small storage container containing neutron and gamma ray sources are reported. Excellent neutron-gamma ray discrimination has been achieved. These neutron-sensing glass optical fibers provide for new methods for monitoring the inventory of, preventing the diversion of, and detecting the unauthorized transport of sensitive nuclear materials. As such, it represents a significant potential element in countering the threat of nuclear terrorism.

  15. Graphite fiber reinforced glass matrix composites for aerospace applications

    NASA Technical Reports Server (NTRS)

    Prewo, K. M.; Bacon, J. F.; Dicus, D. L.

    1979-01-01

    The graphite fiber reinforced glass matrix composite system is described. Although this composite is not yet a mature material, it possesses low density, attractive mechanical properties at elevated temperatures, and good environmental stability. Properties are reported for a borosilicate glass matrix unidirectionally reinforced with 60 volume percent HMS graphite fiber. The flexural strength and fatigue characteristics at room and elevated temperature, resistance to thermal cycling and continuous high temperature oxidation, and thermal expansion characteristics of the composite are reported. The properties of this new composite are compared to those of advanced resin and metal matrix composites showing that graphite fiber reinforced glass matrix composites are attractive for aerospace applications.

  16. Production of Bulk and Fiber Glass in Space

    NASA Technical Reports Server (NTRS)

    Tucker, Dennis S.; Whitaker, Ann F. (Technical Monitor)

    2001-01-01

    The production of bulk glass and fiber glass in space and on the moon and Mars should lead to superior products. Specifically glass plates for windows and optical elements could be produced with theoretical strengths by production in vacuum. Water vapor is known to decrease glass strength by up to two orders of magnitude from theoretical. A low gravity glass plate apparatus prototype has been designed and built which uses centrifugal force to shape the glass and solar energy to melt the glass. Glass fiber could be produced on the moon or Mars from in-situ materials using standard technologies. This material could then be used as reinforcement in composite materials in construction of bases. Also, it has been shown that processing in reduced gravity suppresses crystallization in certain heavy metal fluoride glasses. It is proposed to reprocess optical fiber preforms on the space station and then pull these into optical fiber. It is estimated that the attenuation coefficient should be reduced by two orders of magnitude.

  17. Graphite-Fiber-Reinforced Glass-Matrix Composite

    NASA Technical Reports Server (NTRS)

    Prewo, K. M.; Dicus, D. L.

    1982-01-01

    G/GI structural composite material made of graphite fibers embedded in borosilicate glass exhibit excellent strength, fracture toughness, and dimensional stability at elevated temperatures. It is made by passing graphite-fiber yarn through slurry containing suspension of fine glass particles in carrier liquid and winding on drum to produce prepegged uniaxial tape. After drying, tapes are cut into appropriate lengths and laid up in graphite die in desired stacking scheme. Stack is consolidated by hot pressing in furnace.

  18. Ceramic fiber reinforced glass-ceramic matrix composite

    NASA Technical Reports Server (NTRS)

    Bansal, Narottam P. (Inventor)

    1993-01-01

    A slurry of BSAS glass powders is cast into tapes which are cut to predetermined sizes. Mats of continuous chemical vapor deposition (CVD)-SiC fibers are alternately stacked with these matrix tapes. This tape-mat stack is warm-pressed to produce a 'green' composite which is heated to burn out organic constituents. The remaining interim material is then hot-pressed to form a BSAS glass-ceramic fiber-reinforced composite.

  19. Laser-power delivery using chalcogenide glass fibers

    NASA Astrophysics Data System (ADS)

    Hilton, Albert R., Sr.; Hilton, A. R., Jr.; McCord, James; Loretz, Thomas J.

    1997-04-01

    During the last 15 years, numerous programs have been carried out in the U.S., UK, France, Japan, Israel and Russia aimed at providing a flexible chalcogenide glass fiber suited for delivery of power from a carbon dioxide laser emitting at 10.6 micrometer. The success of these programs has been modest at best with output power limited to 10 watts or less. The purpose of this paper is to examine chalcogenide glasses used for fiber from a thermal lensing standpoint.

  20. Processing Glass Fiber from Moon/Mars Resources

    NASA Technical Reports Server (NTRS)

    Tucker, Dennis S.; Ethridge, Edwin C.

    1998-01-01

    Processing of Lunar/Mars raw materials into usable structural and thermal components for use on a Lunar/Mars base will be essential for human habitation. One such component will be glass fiber which can be used in a number of applications. Glass fiber has been produced from two lunar soil simulants. These two materials simulate lunar mare and lunar highlands soil compositions. Short fibers containing recrystallized areas were produced from the as-received simulants. Doping the highland simulant with 8 weight percent boria yielded a material which could be spun continuously. The effects of lunar gravity on glass fiber formation were studied utilizing NASA's KC 135 aircraft. Gravity was found to play a role in crystallization and final fiber diameter.

  1. Deformation, Stress Relaxation, and Crystallization of Lithium Silicate Glass Fibers Below the Glass Transition Temperature

    NASA Technical Reports Server (NTRS)

    Ray, Chandra S.; Brow, Richard K.; Kim, Cheol W.; Reis, Signo T.

    2004-01-01

    The deformation and crystallization of Li(sub 2)O (center dot) 2SiO2 and Li(sub 2)O (center dot) 1.6SiO2 glass fibers subjected to a bending stress were measured as a function of time over the temperature range -50 to -150 C below the glass transition temperature (Tg). The glass fibers can be permanently deformed at temperatures about 100 C below T (sub)g, and they crystallize significantly at temperatures close to, but below T,, about 150 C lower than the onset temperature for crystallization for these glasses in the no-stress condition. The crystallization was found to occur only on the surface of the glass fibers with no detectable difference in the extent of crystallization in tensile and compressive stress regions. The relaxation mechanism for fiber deformation can be best described by a stretched exponential (Kohlrausch-Williams-Watt (KWW) approximation), rather than a single exponential model.The activation energy for stress relaxation, Es, for the glass fibers ranges between 175 and 195 kJ/mol, which is considerably smaller than the activation energy for viscous flow, E, (about 400 kJ/mol) near T, for these glasses at normal, stress-free condition. It is suspected that a viscosity relaxation mechanism could be responsible for permanent deformation and crystallization of the glass fibers below T,

  2. Lithium Loaded Glass Fiber Neutron Detector Tests

    SciTech Connect

    Ely, James H.; Erikson, Luke E.; Kouzes, Richard T.; Lintereur, Azaree T.; Stromswold, David C.

    2009-11-12

    Radiation portal monitors used for interdiction of illicit materials at borders include highly sensitive neutron detection systems. The main reason for having neutron detection capability is to detect fission neutrons from plutonium. The currently deployed radiation portal monitors (RPMs) from Ludlum and Science Applications International Corporation (SAIC) use neutron detectors based upon 3He-filled gas proportional counters, which are the most common large neutron detector. There is a declining supply of 3He in the world and, thus, methods to reduce the use of this gas in RPMs with minimal changes to the current system designs and sensitivity to cargo-borne neutrons are being investigated. Four technologies have been identified as being currently commercially available, potential alternative neutron detectors to replace the use of 3He in RPMs. Reported here are the results of tests of the lithium-loaded glass fibers option. This testing measured the neutron detection efficiency and gamma ray rejection capabilities of a small system manufactured by Nucsafe (Oak Ridge, TN).

  3. Hi Nicalon{trademark} SiC fiber reinforced glass and glass-ceramic matrix composites

    SciTech Connect

    Tredway, W.K.

    1996-12-31

    A multi-year research program was conducted by a team consisting of Nippon Carbon Corporation, United Technologies Research Center (UTRC), the University of Tokyo, and the University of Delaware to study and analyze basic mechanisms of failure in SiC fiber reinforced glass matrix composites. This paper presents the results of one portion of this investigation performed by UTRC that studied the mechanical performance and in-situ carbon interfacial layer formation characteristics of glass and glass-ceramic matrix composites reinforced with Hi Nicalon{trademark} SiC fiber. The fiber was produced by Nippon Carbon Corp. and was supplied to UTRC for their use on the program.

  4. Monitoring Fiber Stress During Curing of Single Fiber Glass- and Graphite-Epoxy Composites

    NASA Technical Reports Server (NTRS)

    Madhukar, Madhu S.; Kosuri, Ranga P.; Bowles, Kenneth J.

    1994-01-01

    The difference in thermal expansion characteristics of epoxy matrices and graphite fibers can produce significant residual stresses in the fibers during curing of composite materials. Tests on single fiber glass-epoxy and graphite-epoxy composite specimens were conducted in which the glass and graphite fibers were preloaded in tension, and the epoxy matrix was cast around the fibers. The fiber tension was monitored while the matrix was placed around the fiber and subjected to the temperature-time curing cycle. Two mechanisms responsible for producing stress in embedded fibers were identified as matrix thermal expansion and contraction and matrix cure shrinkage. A simple analysis based on the change in fiber tension during the curing cycle was conducted to estimate the produced stresses. Experimental results on single fiber glass- and graphite-epoxy composites show that the fiber was subjected to significant tensile stresses when the temperature was raised from the first to the second dwell period. When initial fiber pretension is about 60 percent of the fiber failure load, these curing-induced stresses can cause tensile fracture of the embedded fiber.

  5. Fretting maps of glass fiber-reinforced composites

    SciTech Connect

    Turki, C.; Salvia, M.; Vincent, L.

    1993-12-31

    Industrial development of new materials are often limited due to an insufficient knowledge in their functional properties. The paper deals with fretting behavior of glass fiber reinforced epoxy/metal contacts. Fretting is a plague for all industries, especially in the case of quasi-static loadings. Furthermore friction testing under small displacements appeared well fitted to understand the effect of fiber orientations and to relate results to microstructure (fiber, matrix and interface).

  6. Hole drilling on glass optical fibers by a femtosecond laser

    NASA Astrophysics Data System (ADS)

    Hamasaki, Masayuki; Gouya, Kenji; Watanabe, Kazuhiro

    2012-01-01

    A novel optical fiber sensor has been developed for gaseous material detection by means of a femto-second laser which has ultrashort pulse and ultrahigh peak power. This sensor has attractive sensor potion consisted of drilling holes array which is machined on the glass optical fiber. Additionally, the sensor potion is coated with thin gold film. This work expects that an interaction could be induced between transmitted light through fiber core and a bottom of the drilled holes which reaches the fiber core. The interaction could induce near-field optical phenomenon excited by transmitted light through the fiber core. This scheme could make it possible to detect gaseous-material phase substances around the optical fiber. In this study, we found that localized surface plasmon (LSP) was excited by the transmitted light through the fiber core. This paper shows experiment to obtain optimum irradiation conditions and investigation for sensor principle for the development of a novel fiber sensor.

  7. Effect of diameter of glass fibers on flexural properties of fiber-reinforced composites.

    PubMed

    Obukuro, Motofumi; Takahashi, Yutaka; Shimizu, Hiroshi

    2008-07-01

    This study investigated the effect of the diameter of glass fibers on the flexural properties of fiber-reinforced composites. Bar-shaped test specimens of highly filled fiber-reinforced composites (FRCs) and FRC of 30 vol% fiber content were made from a light-cured dimethacrylate monomer liquid (mixture of urethane dimethacrylate and triethylene glycol dimethacrylate) with silanized E-glass fibers (7, 10, 13, 16, 20, 25, 30, and 45 microm in diameter). Flexural strength and elastic modulus were measured. The flexural strength of the highly filled FRCs increased with increasing fiber diameter. In particular, the strengths of highly filled FRCs with 20-, 25-, 30-, and 45-microm-diameter fibers was significantly higher than the others (p<0.05). The flexural strength of FRC of 30 vol% fiber content increased with increasing fiber diameter, except for the FRC with 45-microm-diameter fibers; FRCs with 20-, 25-, and 30-microm-diameter fibers were significantly stronger than the others (p<0.05). Therefore, it was revealed that the diameter of glass fibers significantly affected the flexural properties of fiber-reinforced composites. PMID:18833767

  8. Microwave evaluation of anisotropy in glass and reflection properties of glass fibers under static load

    SciTech Connect

    Frank, M.; Handjojo, L.; Qaddoumi, N.; Bois, K.; Zoughi, R.

    1999-12-02

    Detection and evaluation of glass properties, such as the degree of anisotropy, is an important issue in glass making industry. In addition, a nondestructive means by which glass tensile strength may be correlated to some measurable parameter is also desirable. Microwave nondestructive material characterization techniques have shown great potential for evaluating glass properties. In this study these techniques have been utilized at S- and X-band to determine the potential of evaluating anisotropy and obtain some useful correlation to tensile strength in glass fibers.

  9. Fabrication and characterization of calcium aluminate glass fibers

    NASA Astrophysics Data System (ADS)

    Foy, Paul R.

    Calcium aluminate glasses (CAG) offer excellent chemical durability, high strength, broad spectral transparency, and a refractory nature. This makes them ideal candidates for fiber optic power delivery and sensor systems in the infrared spectrum. CAG also have the potential to form ultra-low loss optical materials. The fabrication of glass optical fibers from CAG was investigated in this study. High quality bulk glasses were obtained from the best industrial sources available. These glasses included silica and baria doped CAG compositions. A preform fabrication method was developed to obtain drawing samples. An optical fiber draw furnace was specially modified to achieve fiber drawing. A novel drawing method was also developed. Solid and hollow CAG waveguides, and CAG core/silica clad waveguides were obtained from drawing preforms. This represents the first successful fiber drawing of this glass system. Teflon coating for optical cladding and strength protection was also investigated. Infrared Spectroscopy was used to assess the attenuation in the drawn fibers. 7 dB/m at 2.7 mum with the baria doped CAG solid waveguide was recorded. This represents the lowest loss documented for fibers fabricated from CAG. Laser power propagation through solid and hollow waveguides was investigated. 24 Watts of CO2 laser power was delivered into a hollow baria doped CAG waveguide. 10.13 J/mm2 of 2.94 mum Erbium YAG laser power was delivered through solid baria doped CAG waveguide. Fiber strength testing was performed on the CAG fibers through four point bend testing. The best strength obtained was 1290 MPa for baria doped CAG. Glass stability was assessed using Differential Thermal Analysis. Fiber surface crystallization products were characterized using Energy Dispersive Analysis, Scanning Electron Microscopy, a specially modified Hot Stage X-Ray, and Guinier Camera X-Ray Analysis. The surface crystallization analysis revealed the formation of Ca3Al2O6 in the silica doped CAG

  10. Laser transmission welding of long glass fiber reinforced thermoplastics

    NASA Astrophysics Data System (ADS)

    van der Straeten, Kira; Engelmann, Christoph; Olowinsky, Alexander; Gillner, Arnold

    2015-03-01

    Joining fiber reinforced polymers is an important topic for lightweight construction. Since classical laser transmission welding techniques for polymers have been studied and established in industry for many years joint-strengths within the range of the base material can be achieved. Until now these processes are only used for unfilled and short glass fiber-reinforced thermoplastics using laser absorbing and laser transparent matrices. This knowledge is now transferred to joining long glass fiber reinforced PA6 with high fiber contents without any adhesive additives. As the polymer matrix and glass fibers increase the scattering of the laser beam inside the material, their optical properties, changing with material thickness and fiber content, influence the welding process and require high power lasers. In this article the influence of these material properties (fiber content, material thickness) and the welding parameters like joining speed, laser power and clamping pressure are researched and discussed in detail. The process is also investigated regarding its limitations. Additionally the gap bridging ability of the process is shown in relation to material properties and joining speed.

  11. Hybrid polymer photonic crystal fiber with integrated chalcogenide glass nanofilms.

    PubMed

    Markos, Christos; Kubat, Irnis; Bang, Ole

    2014-01-01

    The combination of chalcogenide glasses with polymer photonic crystal fibers (PCFs) is a difficult and challenging task due to their different thermo-mechanical material properties. Here we report the first experimental realization of a hybrid polymer-chalcogenide PCF with integrated As2S3 glass nanofilms at the inner surface of the air-channels of a poly-methyl-methacrylate (PMMA) PCF. The integrated high refractive index glass films introduce distinct antiresonant transmission bands in the 480-900 nm wavelength region. We demonstrate that the ultra-high Kerr nonlinearity of the chalcogenide glass makes the polymer PCF nonlinear and provides a possibility to shift the transmission band edges as much as 17 nm by changing the intensity. The proposed fabrication technique constitutes a new highway towards all-fiber nonlinear tunable devices based on polymer PCFs, which at the moment is not possible with any other fabrication method. PMID:25317501

  12. Scintillating glass fiber neutron sensors: 1, Production and optical characterization

    SciTech Connect

    Abel, K.H.; Arthur, R.J.; Bliss, M.

    1993-10-01

    The production and optical characterization of cerium-doped lithium silicate scintillating fibers used as thermal neutron detectors are discussed. The bulk glass continuing enriched {sup 6}Li is produced starting from high-purity commercial materials which are further purified at Pacific Northwest Laboratory (PNL). The fibers are drawn at PNL in a hot down-draw process. The fibers are coated with a silicone polymer that serves as both an optical cladding and a physical buffer coat. Optical characterization has included measurements of light output as a function of glass composition, optical attenuation lengths, and fluorescence lifetimes. Fibers have been prepared in our laboratory with as-drawn attenuation lengths (l/e distance) in excess of 2 meters over sub-meter distances.

  13. Quality assurance of glass fiber reinforced piping systems

    SciTech Connect

    Ende, C.A.M. van den; Bruijn, J.C.M. de

    1997-12-01

    Resin based glass fiber reinforced plastic piping systems have been in use for over 30 years in a variety of industrial purposes, e.g. cooling and potable water, crude oil, gas, etc. Glass fiber reinforced piping systems have considerable advantages over alternative materials for piping systems. This is mainly due to their high corrosion resistance. The use of GRP pipes is limited due to the lack of quality assurance. As with other piping systems the joint is the weakest point. The paper describes the effort made towards a better quality control and understanding of the failure through determination of acceptance criteria and development of nondestructive testing methods for adhesively bounded joints.

  14. Self-Frequency-Doubling Glass-Fiber Laser

    NASA Technical Reports Server (NTRS)

    Selker, Mark D.; Dallas, Joseph L.

    1993-01-01

    Specially prepared germanium and phosphorous-doped glass optical fiber doped with neodymium shown to act as self-frequency-doubling laser. Self-frequency-doubling fiber laser with further refinements, eliminates need for expensive, easily damaged, nonlinear crystals currently used. Enables one to avoid loss and damage mechanisms associated with interfaces of nonlinear crystals as well as to eliminate angle/temperature phase-matching tuning.

  15. Adhesion between thermoplastic polymer particles and carbon and glass fibers

    SciTech Connect

    Colton, J.S.

    1996-12-31

    High performance composites consist of polymer matrices reinforced with continuous fibers. Polymer powders can be coated and fused onto the fibers by various techniques to produce these composites. One such technique consists of spreading the fibers with an air banding jet, and then running the fibers through a fluidized bed of the powder. The fluidizing air is typically charged, imparting a charge to the powder particles. The fibers are grounded which leads to an attraction between the particles and the fibers. The particle-coated fibers then go through a tunnel oven, sintering the particles onto the fibers, leaving a flexible {open_quotes}tow-preg{close_quotes} which can then be processed into a preform for manufacture into a final part. To develop an initial understanding of the powder coating process, the adhesion of uncharged particles and fibers was studied. Contact mechanics predicts that the adhesion force between uncharged particles depends on the mutual (or equivalent) radius of curvature between the contacting objects, as well as their surface energies. For the materials of interest, the Derjaguin approximation is appropriate and is applied. PEEK (poly ether ether ketone) and PET (poly ethylene terephthalate) particles, cryogenically ground to nominal diameters of 10 to 100 {mu}m were brought into contact with themselves, with E-glass fibers (nominal diameter of 20 {mu}m), carbon fibers (nominal diameter of 8 {mu}m), and glass microscope slides using an AFM. Adhesion forces were measured and compared to predictions using Derjaguin`s approximation. SEM micrographs were used to determine the scale of the radii of curvature of contacting sites.

  16. Containerless high purity pulling process and apparatus for glass fiber

    NASA Technical Reports Server (NTRS)

    Naumann, R. J.; Ethridge, E. C. (Inventor)

    1986-01-01

    Apparatus and method for pulling optical glass fibers in a containerless environment is disclosed which includes a single axis acoustical levitation furnace in which a specimen is levitated and melted. A reflector unit is carried in the interior of the furnace and includes a reflector disposed centrally about the acoustical axis of the levitator. The reflector unit includes a circular shroud of insulation and a copper sleeve inserted in the unit which is hollow at for receiving a cooling medium. A fiber pulling bore is formed centrally in the reflector unit surrounded by cooling jacket to enhance solidification and formation of a fiber. A starting fiber strand is introduced into the melt and pulled outwardly through bore whereby the specimen fiber is started and formed as pulled therethrough. In order to replenish the melt and thus enable a continous process, a movable secondary reflector is provided which captures a supplemental specimen pellet and by movement of the reflector transfers it to the melt.

  17. Liquid crystals detect voids in fiber glass laminates

    NASA Technical Reports Server (NTRS)

    Hollar, W. T.

    1967-01-01

    Liquid crystal solution nondestructively detects voids or poor bond lines in fiber glass laminates. A thin coating of the solution is applied by spray or brush to the test article surface, and when heated indicates the exact location of defects by differences in color.

  18. Production of continuous glass fiber using lunar simulant

    NASA Technical Reports Server (NTRS)

    Tucker, Dennis S.; Ethridge, Edwin C.; Curreri, Peter A.

    1991-01-01

    The processing parameters and mechanical properties of glass fibers pulled from simulated lunar basalt are tested. The simulant was prepared using a plasma technique. The composition is representative of a low titanium mare basalt (Apollo sample 10084). Lunar gravity experiments are to be performed utilizing parabolic aircraft free-fall maneuvers which yield 30 seconds of 1/6-g per maneuver.

  19. Design Guide for glass fiber reinforced metal pressure vessel

    NASA Technical Reports Server (NTRS)

    Landes, R. E.

    1973-01-01

    Design Guide has been prepared for pressure vessel engineers concerned with specific glass fiber reinforced metal tank design or general tank tradeoff study. Design philosophy, general equations, and curves are provided for safelife design of tanks operating under anticipated space shuttle service conditions.

  20. Polyimide fiber-glass composite resists high temperatures

    NASA Technical Reports Server (NTRS)

    Gilwee, W. J.; Rosser, R. W.; Parker, J. A.

    1973-01-01

    Composites synthesized from bismaleimide have superior strength and oxidation resistance at elevated temperatures when compared with similar composites prepared with epoxy or silicon polymers of similar cost. Polyimide synthesis technique and processing method yield essentially void-free fiber-glass reinforced composites.

  1. INFLUENCE OF DIFFERENT ADHESIVE SYSTEMS ON THE PULL-OUT BOND STRENGTH OF GLASS FIBER POSTS

    PubMed Central

    da Silva, Luciana Mendonça; de Andrade, Andréa Mello; Machuca, Melissa Fernanda Garcia; da Silva, Paulo Maurício Batista; da Silva, Ricardo Virgolino C.; Veronezi, Maria Cecília

    2008-01-01

    This in vitro study evaluated the tensile bond strength of glass fiber posts (Reforpost – Angelus-Brazil) cemented to root dentin with a resin cement (RelyX ARC – 3M/ESPE) associated with two different adhesive systems (Adper Single Bond - 3M/ESPE and Adper Scotchbond Multi Purpose (MP) Plus – 3M/ESPE), using the pull-out test. Twenty single-rooted human teeth with standardized root canals were randomly assigned to 2 groups (n=10): G1- etching with 37% phosphoric acid gel (3M/ESPE) + Adper Single Bond + #1 post (Reforpost – Angelus) + four #1 accessory posts (Reforpin – Angelus) + resin cement; G2- etching with 37% phosphoric acid gel + Adper Scotchbond MP Plus + #1 post + four #1 accessory posts + resin cement. The specimens were stored in distilled water at 37°C for 7 days and submitted to the pull-out test in a universal testing machine (EMIC) at a crosshead speed of 0.5 mm/min. The mean values of bond strength (kgf) and standard deviation were: G1- 29.163 ± 7.123; G2- 37.752 ±13.054. Statistical analysis (Student's t-test; α=0.05 showed no statistically significant difference (p<0.05) between the groups. Adhesive bonding failures between resin cement and root canal dentin surface were observed in both groups, with non-polymerized resin cement in the apical portion of the post space when Single Bond was used (G1). The type of adhesive system employed on the fiber post cementation did not influence the pull-out bond strength. PMID:19089224

  2. Durability of waste glass flax fiber reinforced mortar

    SciTech Connect

    Aly, M.; Hashmi, M. S. J.; Olabi, A. G.; Messeiry, M.

    2011-01-17

    The main concern for natural fibre reinforced mortar composites is the durability of the fibres in the alkaline environment of cement. The composites may undergo a reduction in strength as a result of weakening of the fibres by a combination of alkali attack and fibre mineralisation. In order to enhance the durability of natural fiber reinforced cement composites several approaches have been studied including fiber impregnation, sealing of the matrix pore system and reduction of matrix alkalinity through the use of pozzolanic materials. In this study waste glass powder was used as a pozzolanic additive to improve the durability performance of flax fiber reinforced mortar (FFRM). The durability of the FFRM was studied by determining the effects of ageing in water and exposure to wetting and drying cycles; on the microstructures and flexural behaviour of the composites. The mortar tests demonstrated that the waste glass powder has significant effect on improving the durability of FFRM.

  3. Durability of Waste Glass Flax Fiber Reinforced Mortar

    NASA Astrophysics Data System (ADS)

    Aly, M.; Hashmi, M. S. J.; Olabi, A. G.; Messeiry, M.

    2011-01-01

    The main concern for natural fibre reinforced mortar composites is the durability of the fibres in the alkaline environment of cement. The composites may undergo a reduction in strength as a result of weakening of the fibres by a combination of alkali attack and fibre mineralisation. In order to enhance the durability of natural fiber reinforced cement composites several approaches have been studied including fiber impregnation, sealing of the matrix pore system and reduction of matrix alkalinity through the use of pozzolanic materials. In this study waste glass powder was used as a pozzolanic additive to improve the durability performance of flax fiber reinforced mortar (FFRM). The durability of the FFRM was studied by determining the effects of ageing in water and exposure to wetting and drying cycles; on the microstructures and flexural behaviour of the composites. The mortar tests demonstrated that the waste glass powder has significant effect on improving the durability of FFRM.

  4. Characterization and reactivity of sodium aluminoborosilicate glass fiber surfaces

    NASA Astrophysics Data System (ADS)

    Ortiz Rivera, Lymaris; Bakaev, Victor A.; Banerjee, Joy; Mueller, Karl T.; Pantano, Carlo G.

    2016-05-01

    Multicomponent complex oxides, such as sodium aluminoborosilicate glass fibers, are important materials used for thermal insulation in buildings and homes. Although the surface properties of single oxides, such as silica, have been extensively studied, less is known about the distribution of reactive sites at the surface of multicomponent oxides. Here, we investigated the reactivity of sodium aluminoborosilicate glass fiber surfaces for better understanding of their interface chemistry and bonding with acrylic polymers. Acetic acid (with and without a 13C enrichment) was used as a probe representative of the carboxylic functional groups in many acrylic polymers and adhesives. Inverse gas chromatography coupled to a mass spectrometer (IGC-MS), and solid state nuclear magnetic resonance (NMR), were used to characterize the fiber surface reactions and surface chemical structure. In this way, we discovered that both sodium ions in the glass surface, as well as sodium carbonate salts that formed on the surface due to the intrinsic reactivity of this glass in humid air, are primary sites of interaction with the carboxylic acid. Surface analysis by X-ray photoelectron spectroscopy (XPS) confirmed the presence of sodium carbonates on these surfaces. Computer simulations of the interactions between the reactive sites on the glass fiber surface with acetic acid were performed to evaluate energetically favorable reactions. The adsorption reactions with sodium in the glass structure provide adhesive bonding sites, whereas the reaction with the sodium carbonate consumes the acid to form sodium-carboxylate, H2O and CO2 without any contribution to chemical bonding at the interface.

  5. Fabrication and characterization of chalcogenide glass for hollow Bragg fibers

    SciTech Connect

    Bowden, Bradley F.; Harrington, James A.

    2009-06-01

    Low- and high-refractive-index chalcogenide glasses are studied for their potential use in the fabrication of one-dimensional hollow Bragg fibers. The low-index glasses are based on the GeSe-glass systems with indices varying from 2.0 to 2.5, while the high-index glasses are formed from the AgAsSe glasses with indices ranging from 2.8 to 3.8. High-purity elemental starting materials are distilled and the surface oxides removed prior to mixing in a rocking furnace. The refractive indices of the AgAsSe glasses, measured using a CO2 laser reflectometer, were near 3.10 for the compositions most compatible with the low-index Ge20Se80 glass (n=2.46). Spectral measurements show impurity absorption bands between 12 and 16 {mu}m. The loss at 10.6 {mu}m for the Ag25As40Se35 glass measured using CO2 laser calorimetry was 1.16x10{sup -3} cm{sup -1}.

  6. Infrared glass fiber cables for CO laser medical applications

    NASA Astrophysics Data System (ADS)

    Arai, Tsunenori; Mizuno, Kyoichi; Sensaki, Koji; Kikuchi, Makoto; Watanabe, Tamishige; Utsumi, Atsushi; Takeuchi, Kiyoshi; Akai, Yoshiro

    1993-05-01

    We developed the medical fiber cables which were designed for CO laser therapy, i.e., angioplasty and endoscopic therapy. As-S chalcogenide glass fibers were used for CO laser delivery. A 230 micrometers core-diameter fiber was used for the angioplasty laser cable. The outer diameter of this cable was 600 micrometers . The total length and insertion length of the angioplasty laser cable were 2.5 m and 1.0 m, respectively. Typically, 2.0 W of fiber output was used in the animal experiment in vivo for the ablation of the model plaque which consisted of human atheromatous aorta wall. The transmission of the angioplasty laser cable was approximately 35%, because the reflection loss occurred at both ends of the fiber and window. Meanwhile, the core diameter of the energy delivery fiber for the endoscopic therapy was 450 micrometers . The outer diameter of this cable was 1.7 mm. Approximately 4.5 W of fiber output was used for clinical treatment of pneumothorax through a pneumoscope. Both types of the cables had the ultra-thin thermocouples for temperature monitoring at the tip of the cables. This temperature monitoring was extremely useful to prevent the thermal destruction of the fiber tip. Moreover, the As-S glass fibers were completely sealed by the CaF2 windows and outer tubes. Therefore, these cables were considered to have sufficient safety properties for medical applications. These laser cables were successfully used for the in vivo animal experiments and/or actual clinical therapies.

  7. Remote Fiber Laser Cutting System for Dismantling Glass Melter - 13071

    SciTech Connect

    Mitsui, Takashi; Miura, Noriaki; Oowaki, Katsura; Kawaguchi, Isao; Miura, Yasuhiko; Ino, Tooru

    2013-07-01

    Since 2008, the equipment for dismantling the used glass melter has been developed in High-level Liquid Waste (HLW) Vitrification Facility in the Japanese Rokkasho Reprocessing Plant (RRP). Due to the high radioactivity of the glass melter, the equipment requires a fully-remote operation in the vitrification cell. The remote fiber laser cutting system was adopted as one of the major pieces of equipment. An output power of fiber laser is typically higher than other types of laser and so can provide high-cutting performance. The fiber laser can cut thick stainless steel and Inconel, which are parts of the glass melter such as casings, electrodes and nozzles. As a result, it can make the whole of the dismantling work efficiently done for a shorter period. Various conditions of the cutting test have been evaluated in the process of developing the remote fiber cutting system. In addition, the expected remote operations of the power manipulator with the laser torch have been fully verified and optimized using 3D simulations. (authors)

  8. Response of perifused alveolar macrophages to glass fibers: effect of exposure duration and fiber length

    SciTech Connect

    Forget, G.; Lacroix, M.J.; Brown, R.C.; Evans, P.H.; Sirois, P.

    1986-01-01

    The effect of glass fibers on rat alveolar macrophages was studied with a new perifusion technique which allows the sequential determination of cell-derived inflammatory mediators as well as estimation of cell viability and aggregation at the end of the incubation period. Results showed that glass fibers induced dose-dependent release of prostaglandins and B-glucuronidase from macrophages and the aggregation and death of these cells. These deleterious effects were clearly related to the length of the fibers, with the longer fibers (greater than or equal to4-5 ..mu..m) being more active than the shorter ones (<3 ..mu..m). Furthermore, a short exposure of 1 hr followed by an 18-hr perifusion induced the same inflammatory and toxic effects on the macrophages as did leaving the fibers undisturbed for the complete 18-hr perifusion. Measurement of prostaglandins was performed by radioimmunoassay. It is concluded that glass fibers produce effects in cultures of rat alveolar macrophages qualitatively similar to those of asbestos, and that fiber length appears to be a critical determinant of toxicity.

  9. Silver metaphosphate glass wires inside silica fibers--a new approach for hybrid optical fibers.

    PubMed

    Jain, Chhavi; Rodrigues, Bruno P; Wieduwilt, Torsten; Kobelke, Jens; Wondraczek, Lothar; Schmidt, Markus A

    2016-02-22

    Phosphate glasses represent promising candidates for next-generation photonic devices due to their unique characteristics, such as vastly tunable optical properties, and high rare earth solubility. Here we show that silver metaphosphate wires with bulk optical properties and diameters as small as 2 µm can be integrated into silica fibers using pressure-assisted melt filling. By analyzing two types of hybrid metaphosphate-silica fibers, we show that the filled metaphosphate glass has only negligible higher attenuation and a refractive index that is identical to the bulk material. The presented results pave the way towards new fiber-type optical devices relying on metaphosphate glasses, which are promising materials for applications in nonlinear optics, sensing and spectral filtering. PMID:26906989

  10. Product stewardship and science: safe manufacture and use of fiber glass.

    PubMed

    Hesterberg, Thomas W; Anderson, Robert; Bernstein, David M; Bunn, William B; Chase, Gerald A; Jankousky, Angela Libby; Marsh, Gary M; McClellan, Roger O

    2012-03-01

    This paper describes a proactive product stewardship program for glass fibers. That effort included epidemiological studies of workers, establishment of stringent workplace exposure limits, liaison with customers on safe use of products and, most importantly, a research program to evaluate the safety of existing glass fiber products and guide development of new even safer products. Chronic inhalation exposure bioassays were conducted with rodents and hamsters. Amosite and crocidolite asbestos produced respiratory tract cancers as did exposure to "biopersistent" synthetic vitreous fibers. "less biopersistent" glass fibers did not cause respiratory tract cancers. Corollary studies demonstrated the role of slow fiber dissolution rates and biopersistence in cancer induction. These results guided development of safer glass fiber products and have been used in Europe to regulate fibers and by IARC and NTP in classifying fibers. IARC concluded special purpose fibers and refractory ceramic fibers are "possibly carcinogenic to humans" and insulation glass wool, continuous glass filament, rock wool and slag wool are "not classifiable as to their carcinogenicity to human." The NTP's 12th report on carcinogens lists "Certain Glass Wool Fibers (Inhalable)" as "reasonably anticipated to be a human carcinogen." "Certain" in the descriptor refers to "biopersistent" glass fibers and excludes "less biopersistent" glass fibers. PMID:22266014

  11. Biological glass fibers: Correlation between optical and structural properties

    PubMed Central

    Aizenberg, Joanna; Sundar, Vikram C.; Yablon, Andrew D.; Weaver, James C.; Chen, Gang

    2004-01-01

    Biological systems have, through the course of time, evolved unique solutions for complex optical problems. These solutions are often achieved through a sophisticated control of fine structural features. Here we present a detailed study of the optical properties of basalia spicules from the glass sponge Euplectella aspergillum and reconcile them with structural characteristics. We show these biosilica fibers to have a distinctive layered design with specific compositional variations in the glass/organic composite and a corresponding nonuniform refractive index profile with a high-index core and a low-index cladding. The spicules can function as single-mode, few-mode, or multimode fibers, with spines serving as illumination points along the spicule shaft. The presence of a lens-like structure at the end of the fiber increases its light-collecting efficiency. Although free-space coupling experiments emphasize the similarity of these spicules to commercial optical fibers, the absence of any birefringence, the presence of technologically inaccessible dopants in the fibers, and their improved mechanical properties highlight the advantages of the low-temperature synthesis used by biology to construct these remarkable structures. PMID:14993612

  12. Electrical Insulation Characteristics of Glass Fiber Reinforced Resins

    SciTech Connect

    Tuncer, Enis; Sauers, Isidor; James, David Randy; Ellis, Alvin R

    2009-01-01

    Non-metallic structural materials that act as an electrical insulation are needed for cryogenic power applications. One of the extensively utilized materials is glass fiber reinforced resins (GFRR) and may also be known as GFRP and FRP. They are created from glass fiber cloth that are impregnated with an epoxy resin under pressure and heat. Although the materials based on GFRR have been employed extensively, reports about their dielectric properties at cryogenic temperatures and larger thicknesses are generally lacking in the literature. Therefore to guide electrical apparatus designers for cryogenic applications, GFRR samples with different thicknesses are tested in a liquid nitrogen bath. Scaling relation between the dielectric breakdown strength and the GFFR thickness is established. Their loss tangents are also reported at various frequencies.

  13. Dynamic tensile strength of glass fiber reinforced pultruded composites

    SciTech Connect

    Dutta, P.K.; Kumar, M.M.; Hui, D.

    1994-12-31

    This paper discusses the stress-strain behavior, fracture strength, influence of low temperature, and energy absorption in the diametral tensile splitting fracturing of a Glass Fiber Reinforced Polymer Composite. Experiments were conducted at low-temperature in a thermal chamber installed on a servo-hydraulic universal testing machine. The tensile strength was determined by diametral compression of disc samples at 24, {minus}5 and {minus}40 C.

  14. Diffusion between glass and metals for optical fiber preform extrusion

    NASA Astrophysics Data System (ADS)

    Yeo, Felicia Yan Xin; Zhang, Zhifeng; Kumar Chakkathara Janardhanan Nair, Dileep; Zhang, Yilei

    2015-07-01

    When silica is extruded, diffusion of metal atoms into silica results contamination to the silica being heated, and thus is a serious concern for the glass extrusion process, such as extrusion of glass fiber preform. This paper examines diffusion between fused silica and two high strength metals, the stainless steel SS410 and the superalloy Inconel 718, at 1000 °C and under the normal atmosphere condition by SEM and Electron Dispersion Spectrum. It is found that diffusion occurs between silica and SS410, and at the same time, SS410 is severely oxidized during diffusion experiment. On the contrary, the diffusion between Inconel 718 and silica is unnoticeable, suggesting excellent high temperature performance of Inconel 718 for glass extrusion.

  15. Mode coupling in glass optical fibers and liquid-core optical fibers by three methods

    NASA Astrophysics Data System (ADS)

    Djordjevich, Alexandar; Savović, Svetislav

    2015-12-01

    We test Slemon and Wells's function and recently reported Hurand et al.'s (Appl. Opt., 50, 492-499, 2011) function for calculation of coupling characteristics in step-index optical fibers against experimental measurements and against calculations by a related method that is based on the power flow equation. Compared are the coupling length Lc (which is the fiber length where the equilibrium mode distribution is achieved) and length zs (where steady-state distribution is achieved) in three step index glass optical fibers as well as a liquid core optical fiber. The two functions, while simpler to apply being just algebraic formulas, are less accurate over a wide range of numerical apertures. It is also shown that fibers with same coupling coefficient can have much different coupling characteristics.

  16. Scintillating glass fiber neutron sensors: 3, Photon economy in scintillating fibers

    SciTech Connect

    Abel, K.H.; Arthur, R.J.; Bliss, M.

    1993-10-01

    In an optical detector such as those constructed from scintillating glass fibers, the photons represent information. This study of the flow of information in a system of devices using PNL glass fibers was undertaken in order to resolve the conflict between expected and observed peak heights. This work concentrates on the number of photons produced and the fraction of photons trapped. It is found that the number of photons produced in bulk samples of the standard glass is about one-third that expected, based on published values; there is evidence that, in fiberized glass, this may be as small as one-fifth the expected value. Additionally, the fraction of trapped photons is found to be about three-fourths that expected because the glass has a smaller refractive index and the cladding a larger refractive index than published values in the spectral region of importance. These factors, taken together, are sufficient to resolve the conflict between the expected and observed peak heights. This analysis provides guidance for those who would use published materials properties to fabricate detectors in a new geometry where the materials properties may have been changed by the fabrication process.

  17. Array fiber welding on micro optical glass substrates for chip-to-fiber coupling

    NASA Astrophysics Data System (ADS)

    Schröder, Henning; Neitz, Marcel; Brusberg, Lars; Queiser, Marco; Arndt-Staufenbiel, Norbert; Lang, K.-D.

    2014-03-01

    High bandwidth parallel optical transceivers are highly demanded for optical interconnects in data centers and in high performance computing. Such transceivers are composed of VCSEL- and photodiode components which have to be fiber coupled, and the appropriate driving and amplifying circuitry. For high density fiber optical connectors lens arrays for improved coupling efficiency have to be used. We propose an advantageous adhesive free method to interconnect optical fibers with such kind of lens arrays. Common approaches using adhesive bonding have high challenges in terms of yield, reliability and optical performance. We introduce our novel fiber welding approach for joining directly fused silica fibers on borosilicate glass substrates with integrated micro optics, e.g. lenses and lens arrays. It is a thermal process with a precise heat input by CO2-laser processing, which is combinable with sequential passive or active alignment of each single fiber to the substrate causing flexibility and highest coupling efficiencies. Since the fiber is accessed only from one side, a two dimensional high-density fiber array can be realized. The manufacturing time of such an interconnection is very short. Due to the adhesive free interface high power transmission is enabled and the occurrence of polymer caused misalignment and degradation are prevented. The paper presents current results in thin glass-based opto-electronic packaging. In particular our laboratory setup for array fiber welding and experimental results of such connections will be discussed and compared to UV-adhesive joining. Also further investigation, for example optical characterization and reliability tests are included. Finally a machine concept, which is under development, will be discussed.

  18. Durability-Based Design Criteria for a Chopped-Glass-Fiber Automotive Structural Composite

    SciTech Connect

    Battiste, R.L.; Corum, J.M.; Ren, W.; Ruggles, M.B.

    1999-11-01

    This report provides recommended durability-based design criteria for a chopped-glass-fiber reinforced polymeric composite for automotive structural applications. The criteria closely follow the framework of an earlier criteria document for a continuous-strand-mat (CSM) glass-fiber reference composite. Together these design criteria demonstrate a framework that can be adapted for future random-glass-fiber composites for automotive structural applications.

  19. Optimization of the contents of hollow glass microsphere and sodium hexametaphosphate for glass fiber vacuum insulation panel

    NASA Astrophysics Data System (ADS)

    Li, C. D.; Chen, Z. F.; Zhou, J. M.

    2016-07-01

    In this paper, various additive amounts of hollow glass microspheres (HGMs) and sodium hexametaphosphate (SHMP) powders were blended with flame attenuated glass wool (FAGW) to form hybrid core materials (HCMs) through the wet method. Among them, the SHMP was dissolved in the glass fiber suspension and coated on the surface of glass fibers while the HGMs were insoluble in the glass fiber suspension and filled in the fiber-fiber pores. The average pore diameter of the FAGW/HGM HCMs was 8-11 μm which was near the same as that of flame attenuated glass fiber mats (FAGMs, i.e., 10.5 µm). The tensile strength of the SHMP coated FAGMs was enhanced from 160 N/m to 370 N/m when SHMP content increased from 0 wt.% to 0.2 wt.%. By contrast, the tensile strength of the FAGW/HGM HCMs decreased from 160 N/m to 40 N/m when HGM content increased from 0 wt.% to 50 wt.%. Both the FAGW/HGM HCMs and SHMP coated FAGMs were vacuumed completely to form vacuum insulation panels (VIPs). The results showed that both the addition of SHMP and HGM led a slight increase in the thermal conductivity of the corresponding VIPs. To obtain a high-quality VIP, the optimal SHMP content and HGM content in glass fiber suspension was 0.12-0.2 wt.% and 0 wt.%.

  20. Synthesis of nanocrystals in KNb(Ge,Si)O{sub 5} glasses and chemical etching of nanocrystallized glass fibers

    SciTech Connect

    Enomoto, Itaru; Benino, Yasuhiko; Fujiwara, Takumi; Komatsu, Takayuki . E-mail: komatsu@chem.nagaokaut.ac.jp

    2006-06-15

    The nanocrystallization behavior of 25K{sub 2}O-25Nb{sub 2}O{sub 5}-(50-x)GeO{sub 2}-xSiO{sub 2} glasses with x=0,25,and50 (i.e., KNb(Ge,Si)O{sub 5} glasses) and the chemical etching behavior of transparent nanocrystallized glass fibers have been examined. All glasses show nanocrystallization, and the degree of transparency of the glasses studied depends on the heat treatment temperature. Transparent nanocrystallized glasses can be obtained if the glasses are heat treated at the first crystallization peak temperature. Transparent nanocrystallized glass fibers with a diameter of about 100{mu}m in 25K{sub 2}O-25Nb{sub 2}O{sub 5}-50GeO{sub 2} are fabricated, and fibers with sharpened tips (e.g., the taper length is about 450{mu}m and the tip angle is about 12{sup o}) are obtained using a meniscus chemical etching method, in which etching solutions of 10wt%-HF/hexane and 10M-NaOH/hexane are used. Although the tip (aperture size) has not a nanoscaled size, the present study suggests that KNb(Ge,Si)O{sub 5} nanocrystallized glass fibers have a potential for new near-field optical fiber probes with high refractive indices of around n=1.8 and high dielectric constants of around {epsilon}=58 (1kHz, room temperature)

  1. Development of Cu-E-Glass Fiber Composites by Powder Metallurgy Route

    NASA Astrophysics Data System (ADS)

    Bhuyan, Pallabi; Singh, Harspreet; Kumar, Lailesh; Sharma, Nidhi; Panda, Deepankar; Verma, Deepanshu; NasmulAlam, Syed

    2016-02-01

    Cu-E glass fiber composites were developed with different vol. % of E-glass fiber (10, 20, 30 and 40 vol. %) by powder metallurgy route. Both as-received Cu and nanostructured Cu developed by milling as-received Cu powder for 20 h were used to develop various Cu-E-glass fiber composites. The effect of using as-received Cu powder and nanostructured Cu powder on the properties of the various Cu-E-glass fiber composites was analysed. The samples were sintered at 900oC for 1 h in inert atmosphere. The results show good bonding between the matrix and the reinforcement and there is homogeneous distribution of the reinforcement in the matrix.. The hardness of the Cu-E-glass fiber composites was found to increase from 0.8GPa to 2.7GPa with increase in vol. % of the glass fiber in case of unmilled and from 1.2GPa to 2.9GPa for the milled Cu-E-glass fiber composites. The as-milled Cu-E- glass fiber composites shows better densification and sinterability compared to the unmilled CuE-glass fiber composites

  2. Glass fiber reinforced concrete for terrestrial photovoltaic arrays

    NASA Technical Reports Server (NTRS)

    Maxwell, H.

    1979-01-01

    The use of glass-fiber-reinforced concrete (GRC) as a low-cost structural substrate for terrestrial solar cell arrays is discussed. The properties and fabrication of glass-reinforced concrete structures are considered, and a preliminary design for a laminated solar cell assembly built on a GRC substrate is presented. A total cost for such a photovoltaic module, composed of a Korad acrylic plastic film front cover, an aluminum foil back cover, an ethylene/vinyl acetate pottant/adhesive and a cotton fabric electrical isolator in addition to the GRC substrate, of $9.42/sq m is projected, which is less than the $11.00/sq m cost goal set by the Department of Energy. Preliminary evaluations are concluded to have shown the design capabilities and cost effectiveness of GRC; however, its potential for automated mass production has yet to be evaluated.

  3. Characterization of Glass Fiber Separator Material for Lithium Batteries

    NASA Technical Reports Server (NTRS)

    Subbarao, S.; Frank, H.

    1984-01-01

    Characterization studies were carried out on a glass fiber paper that is currently employed as a separator material for some LiSOCl2 primary cells. The material is of the non-woven type made from microfilaments of E-type glass and contains an ethyl acrylate binder. Results from extraction studies and tensile testing revealed that the binder content and tensile strength of the paper were significantly less than values specified by the manufacturer. Scanning electron micrographs revealed the presence of clusters of impurities many of which were high in iron content. Results of emission spectroscopy revealed high overall levels of iron and leaching, followed by atomic absorption measurements, revealed that essentially all of this iron is soluble in SOCl2.

  4. Study of glass preforms for glass fiber optics applications (study of space processing of ceramic materials). [light transmission

    NASA Technical Reports Server (NTRS)

    Wang, F. F. Y.

    1974-01-01

    The feasibility, and technical and economic desirability was studied of space processing of glass preforms for optical fiber transmission applications. The results indicate that space processing can produce glass preforms of equal quality at lower cost than earth bound production, and can produce diameter modulation in the glass preform which promotes mode coupling and lowers the dispersion. The glass composition can be modified through the evaporative and diffusion processes, and graded refractive index profiles can be produced. A brief summary of the state of the art in optical fiber transmission is included.

  5. Low thermal flux glass-fiber tubing for cryogenic service.

    NASA Technical Reports Server (NTRS)

    Hall, C. A.; Pharo, T. J., Jr.; Phillips, J. M.

    1972-01-01

    Study of thin metallic liners which provide leak-free service in cryogenic propulsion plumbing systems and are overwrapped with a glass-fiber composite that provides strength and protection from handling damage. The composite tube is lightweight, strong, and has a very low thermal flux. The resultant reduced boiloff of stored cryogenic propellants yields a substantial weight savings for long-term missions (seven days or greater). Twelve styles of tubing ranging from 1/2 to 5 in. in diameter were fabricated and tested with excellent results for most of the concepts at operating temperatures from +70 to -423 F and operating pressures up to 3000 psi.

  6. Faraday rotation influence factors in tellurite-based glass and fibers

    NASA Astrophysics Data System (ADS)

    Chen, Qiuling; Wang, Hui; Wang, Qingwei; Chen, Qiuping

    2015-09-01

    The Faraday rotation influence factors in tellurite-based glass and fibers were studied by experiments and simulations. TeO2-ZnO-Na2O-BaO glass family was fabricated and characterized in terms of the thermal and magneto-optical properties. Two core-cladding pairs for two fibers were selected from fabricated glasses. The Verdet constants of the glasses and fibers were measured at different wavelengths using a homemade optical bench, and the Verdet constant of fiber was close to that of the bulk glass. The influence from external factors (wavelength, laser power and magnetic field) and internal factors (thermal expansion coefficient difference, refractive index and Verdet constant of core and cladding) on Faraday rotation in fibers was investigated and discussed, and the purpose of this study is to improve the Faraday rotation in tellurite fibers for MO device applications both from internal material property match and external parameter configuration in measurement.

  7. From selenium- to tellurium-based glass optical fibers for infrared spectroscopies.

    PubMed

    Cui, Shuo; Chahal, Radwan; Boussard-Plédel, Catherine; Nazabal, Virginie; Doualan, Jean-Louis; Troles, Johann; Lucas, Jacques; Bureau, Bruno

    2013-01-01

    Chalcogenide glasses are based on sulfur, selenium and tellurium elements, and have been studied for several decades regarding different applications. Among them, selenide glasses exhibit excellent infrared transmission in the 1 to 15 µm region. Due to their good thermo-mechanical properties, these glasses could be easily shaped into optical devices such as lenses and optical fibers. During the past decade of research, selenide glass fibers have been proved to be suitable for infrared sensing in an original spectroscopic method named Fiber Evanescent Wave Spectroscopy (FEWS). FEWS has provided very nice and promising results, for example for medical diagnosis. Then, some sophisticated fibers, also based on selenide glasses, were developed: rare-earth doped fibers and microstructured fibers. In parallel, the study of telluride glasses, which can have transmission up to 28 µm due to its atom heaviness, has been intensified thanks to the DARWIN mission led by the European Space Agency (ESA). The development of telluride glass fiber enables a successful observation of CO₂ absorption band located around 15 µm. In this paper we review recent results obtained in the Glass and Ceramics Laboratory at Rennes on the development of selenide to telluride glass optical fibers, and their use for spectroscopy from the mid to the far infrared ranges. PMID:23666005

  8. Nucleation and Crystallization as Induced by Bending Stress in Lithium Silicate Glass Fibers

    NASA Technical Reports Server (NTRS)

    Reis, Signo T.; Kim, Cheol W.; Brow, Richard K.; Ray, Chandra S.

    2003-01-01

    Glass Fibers of Li2O.2SiO2 (LS2) and Li2O.1.6SiO2 (LS1.6) compositions were heated near, but below, the glass transition temperature for different times while subjected to a constant bending stress of about 1.2 GPa. The nucleation density and the crystallization tendency estimated by differential thermal analysis (DTA) of a glass sample in the vicinity of the maximum of the bending stress increased relative to that of stress-free glass fibers. LS2 glass fibers were found more resistant to nucleation and crystallization than the Ls1.6 glass fibers. These results are discussed in regards to shear thinning effects on glass stability.

  9. A Comparative Study of Natural Fiber and Glass Fiber Fabrics Properties with Metal or Oxide Coatings

    NASA Astrophysics Data System (ADS)

    Lusis, Andrej; Pentjuss, Evalds; Bajars, Gunars; Sidorovicha, Uljana; Strazds, Guntis

    2015-03-01

    Rapidly growing global demand for technical textiles industries is stimulated to develop new materials based on hybrid materials (yarns, fabrics) made from natural and glass fibres. The influence of moisture on the electrical properties of metal and metal oxide coated bast (flax, hemp) fibre and glass fibre fabrics are studied by electrical impedance spectroscopy and thermogravimetry. The bast fibre and glass fiber fabrics are characterized with electrical sheet resistance. The method for description of electrical sheet resistance of the metal and metal oxide coated technical textile is discussed. The method can be used by designers to estimate the influence of moisture on technical data of new metal coated hybrid technical textile materials and products.

  10. Ceramic fiber-reinforced monoclinic celsian phase glass-ceramic matrix composite material

    NASA Technical Reports Server (NTRS)

    Bansal, Narottam P. (Inventor); Dicarlo, James A. (Inventor)

    1994-01-01

    A hyridopolysilazane-derived ceramic fiber reinforced monoclinic celsian phase barium aluminum silicate glass-ceramic matrix composite material is prepared by ball-milling an aqueous slurry of BAS glass powder and fine monoclinic celsian seeds. The fibers improve the mechanical strength and fracture toughness and with the matrix provide superior dielectric properties.

  11. Single frequency fiber laser at 2.05 μm based on Ho-doped germanate glass fiber

    NASA Astrophysics Data System (ADS)

    Wu, Jianfeng; Yao, Zhidong; Zong, Jie; Chavez-Pirson, Arturo; Peyghambarian, Nasser; Yu, Jirong

    2009-02-01

    A single frequency fiber laser operating near 2 micron with over 50 mW output power has been demonstrated by using a short piece of newly developed single mode holmium-doped germanate glass fiber. Laser from 2004 nm to 2083 nm was demonstrated from a short Ho-doped fiber laser cavity. A heavily thulium-doped germanate fiber was used as an in-band pump source for the holmium-doped fiber laser. The single frequency fiber laser can be thermally tuned.

  12. Static and Dynamic Behavior of High Modulus Hybrid Boron/Glass/Aluminum Fiber Metal Laminates

    NASA Astrophysics Data System (ADS)

    Yeh, Po-Ching

    2011-12-01

    This dissertation presents the investigation of a newly developed hybrid fiber metal laminates (FMLs) which contains commingled boron fibers, glass fibers, and 2024-T3 aluminum sheets. Two types of hybrid boron/glass/aluminum FMLs are developed. The first, type I hybrid FMLs, contained a layer of boron fiber prepreg in between two layers of S2-glass fiber prepreg, sandwiched by two aluminum alloy 2024-T3 sheets. The second, type II hybrid FMLs, contained three layer of commingled hybrid boron/glass fiber prepreg layers, sandwiched by two aluminum alloy 2024-T3 sheets. The mechanical behavior and deformation characteristics including blunt notch strength, bearing strength and fatigue behavior of these two types of hybrid boron/glass/aluminum FMLs were investigated. Compared to traditional S2-glass fiber reinforced aluminum laminates (GLARE), the newly developed hybrid boron/glass/aluminum fiber metal laminates possess high modulus, high yielding stress, and good blunt notch properties. From the bearing test result, the hybrid boron/glass/aluminum fiber metal laminates showed outstanding bearing strength. The high fiber volume fraction of boron fibers in type II laminates lead to a higher bearing strength compared to both type I laminates and traditional GLARE. Both types of hybrid FMLs have improved fatigue crack initiation lives and excellent fatigue crack propagation resistance compared to traditional GLARE. The incorporation of the boron fibers improved the Young's modulus of the composite layer in FMLs, which in turn, improved the fatigue crack initiation life and crack propagation rates of the aluminum sheets. Moreover, a finite element model was established to predict and verify the properties of hybrid boron/glass/aluminum FMLs. The simulated results showed good agreement with the experimental results.

  13. Energy absorption at high strain rate of glass fiber reinforced mortars

    NASA Astrophysics Data System (ADS)

    Fenu, Luigi; Forni, Daniele; Cadoni, Ezio

    2015-09-01

    In this paper, the dynamic behaviour of cement mortars reinforced with glass fibers was studied. The influence of the addition of glass fibers on energy absorption and tensile strength at high strain-rate was investigated. Static tests in compression, in tension and in bending were first performed. Dynamic tests by means of a Modified Hopkinson Bar were then carried out in order to investigate how glass fibers affected energy absorption and tensile strength at high strain-rate of the fiber reinforced mortar. The Dynamic Increase Factor (DIF) was finally evaluated.

  14. Graphite fiber reinforced thermoplastic glass matrix composites for use at 1000 F

    NASA Technical Reports Server (NTRS)

    Prewo, K. M.; Minford, E. J.

    1985-01-01

    The fabrication and properties of the graphite fiber reinforced glass matrix composite system are described. By reinforcing borosilicate glass with graphite fibers it has been possible to develop a composite whose properties can be compared favorably with resin matrix counterparts. Both high elastic modulus and strength can be obtained and maintained to temperatures of approximately 600 C. In addition, composite dimensional stability is superior to resin or metal matrix systems due to the low thermal expansion behavior of the glass matrix.

  15. In vitro cytotoxicity of Manville Code 100 glass fibers: Effect of fiber length on human alveolar macrophages

    PubMed Central

    Zeidler-Erdely, Patti C; Calhoun, William J; Ameredes, Bill T; Clark, Melissa P; Deye, Gregory J; Baron, Paul; Jones, William; Blake, Terri; Castranova, Vincent

    2006-01-01

    Background Synthetic vitreous fibers (SVFs) are inorganic noncrystalline materials widely used in residential and industrial settings for insulation, filtration, and reinforcement purposes. SVFs conventionally include three major categories: fibrous glass, rock/slag/stone (mineral) wool, and ceramic fibers. Previous in vitro studies from our laboratory demonstrated length-dependent cytotoxic effects of glass fibers on rat alveolar macrophages which were possibly associated with incomplete phagocytosis of fibers ≥ 17 μm in length. The purpose of this study was to examine the influence of fiber length on primary human alveolar macrophages, which are larger in diameter than rat macrophages, using length-classified Manville Code 100 glass fibers (8, 10, 16, and 20 μm). It was hypothesized that complete engulfment of fibers by human alveolar macrophages could decrease fiber cytotoxicity; i.e. shorter fibers that can be completely engulfed might not be as cytotoxic as longer fibers. Human alveolar macrophages, obtained by segmental bronchoalveolar lavage of healthy, non-smoking volunteers, were treated with three different concentrations (determined by fiber number) of the sized fibers in vitro. Cytotoxicity was assessed by monitoring cytosolic lactate dehydrogenase release and loss of function as indicated by a decrease in zymosan-stimulated chemiluminescence. Results Microscopic analysis indicated that human alveolar macrophages completely engulfed glass fibers of the 20 μm length. All fiber length fractions tested exhibited equal cytotoxicity on a per fiber basis, i.e. increasing lactate dehydrogenase and decreasing chemiluminescence in the same concentration-dependent fashion. Conclusion The data suggest that due to the larger diameter of human alveolar macrophages, compared to rat alveolar macrophages, complete phagocytosis of longer fibers can occur with the human cells. Neither incomplete phagocytosis nor length-dependent toxicity was observed in fiber

  16. Fabrication of an IR hollow-core Bragg fiber based on chalcogenide glass extrusion

    NASA Astrophysics Data System (ADS)

    Zhu, Minming; Wang, Xunsi; Pan, Zhanghao; Cheng, Ci; Zhu, Qingde; Jiang, Chen; Nie, Qiuhua; Zhang, Peiqing; Wu, Yuehao; Dai, Shixun; Xu, Tiefeng; Tao, Guangming; Zhang, Xianghua

    2015-05-01

    The theoretical analysis and experimental preparation of a hollow-core Bragg fiber based on chalcogenide glasses are demonstrated. The fiber has potential applications in bio-sensing and IR energy transmission. Two chalcogenide glasses with, respectively, high and low refractive indexes are investigated in detail for the fabrication of hollow-core Bragg fibers. The most appropriate structure is selected; this structure is composed of four concentric rings and a center air hole . Its band gap for the Bragg fiber is analyzed by the plane wave method. The chalcogenide glasses Ge15Sb20S58.5I13 and Ge15Sb10Se75 are chosen to extrude the robust multi-material glass preform with a specialized punch and glass container. The glass preform is simultaneously protected with a polyetherimide polymer. The hollow-core Bragg fibers are finally obtained after glass preform extrusion, fiber preform fabrication, and fiber drawing. Results showed that the fiber has a transparency window from 2.5 to 14 μm, including a low-loss transmission window from 10.5 to 12 μm. The location of this low-loss transmission window matches the predicted photonic band gap in the simulation.

  17. Kenaf-glass fiber reinforced unsaturated polyester hybrid composites: Tensile properties

    NASA Astrophysics Data System (ADS)

    Zhafer, S. F.; Rozyanty, A. R.; Shahnaz, S. B. S.; Musa, L.; Zuliahani, A.

    2016-07-01

    The use of natural fibers in composite is rising in recent years due their lightweight, non-abrasive, combustible, non-toxic, low cost and biodegradable properties. However, in comparison with synthetic fibers, the mechanical properties of natural fibers are lower. Therefore, the inclusion of synthetic fibers could improve the mechanical performance of natural fiber based composites. In this study, kenaf bast fiber and glass fiber at different weight percentage loading were used as reinforcement to produce hybrid composites. Unsaturated polyester (UP) resin was used as matrix and hand lay-up process was performed to apply the UP resin on the hybrid kenaf bast/glass fiber composite. Effect of different fiber loading on tensile strength, tensile modulus and elongation at break of the hybrid composite was studied. It has been found that the highest value of tensile strength and modulus was achieved at 10 wt.% kenaf/10 wt.% glass fiber loading. It was concluded that addition of glass fiber has improved the tensile properties of kenaf bast fiber based UP composites.

  18. Glass Fiber Reinforced Metal Pressure Vessel Design Guide

    NASA Technical Reports Server (NTRS)

    Landes, R. E.

    1972-01-01

    The Engineering Guide presents curves and general equations for safelife design of lightweight glass fiber reinforced (GFR) metal pressure vessels operating under anticipated Space Shuttle service conditions. The high composite vessel weight efficiency is shown to be relatively insensitive to shape, providing increased flexibility to designers establishing spacecraft configurations. Spheres, oblate speroids, and cylinders constructed of GFR Inconel X-750, 2219-T62 aluminum, and cryoformed 301 stainless steel are covered; design parameters and performance efficiencies for each configuration are compared at ambient and cryogenic temperature for an operating pressure range of 690 to 2760 N/sq cm (1000 to 4000 psi). Design variables are presented as a function of metal shell operating to sizing (proof) stress ratios for use with fracture mechanics data generated under a separate task of this program.

  19. Commercial Production of Heavy Metal Fluoride Glass Fiber in Space

    NASA Technical Reports Server (NTRS)

    Tucker, Dennis S.; Workman, Gary L.; Smith, Guy A.

    1998-01-01

    International Space Station Alpha (ISSA) will provide a platform not only for materials research but also a possible means to produce products in space which cannot be easily produced on the ground. Some products may even be superior to those now produced in unit gravity due to the lack of gravity induced convection effects. Our research with ZrF4-BaF2-LaF3-AlF3-NaF (ZBLAN glass) has shown that gravity does indeed play a major role in the crystallization behavior of this material. At the present time ZBLAN is being produced on earth in fiber optic form for use in surgical lasers and fiber optic lasers among other applications. High attenuation coefficients, however, have kept this material from being used in other applications such as long haul data transmission links. The high attenuation coefficients are due to impurities which can be removed through improved processing techniques and crystals which can only be removed or prevented from forming by processing in a reduced gravity environment.

  20. Silicone polymer waveguide bridge for Si to glass optical fibers

    NASA Astrophysics Data System (ADS)

    Kruse, Kevin L.; Riegel, Nicholas J.; Middlebrook, Christopher T.

    2015-03-01

    Multimode step index polymer waveguides achieve high-speed, (<10 Gb/s) low bit-error-rates for onboard and embedded circuit applications. Using several multimode waveguides in parallel enables overall capacity to reach beyond 100 Gb/s, but the intrinsic bandwidth limitations due to intermodal dispersion limit the data transmission rates within multimode waveguides. Single mode waveguides, where intermodal dispersion is not present, have the potential to further improve data transmission rates. Single mode waveguide size is significantly less than their multimode counterparts allowing for greater density of channels leading to higher bandwidth capacity per layer. Challenges in implementation of embedded single mode waveguides within printed circuit boards involves mass production fabrication techniques to create precision dimensional waveguides, precision alignment tolerances necessary to launch a mode, and effective coupling between adjoining waveguides and devices. An emerging need in which single mode waveguides can be utilized is providing low loss fan out techniques and coupling between on-chip transceiver devices containing Si waveguide structures to traditional single mode optical fiber. A polymer waveguide bridge for Si to glass optical fibers can be implemented using silicone polymers at 1310 nm. Fabricated and measured prototype devices with modeling and simulation analysis are reported for a 12 member 1-D tapered PWG. Recommendations and designs are generated with performance factors such as numerical aperture and alignment tolerances.

  1. The characterization of carbon nanotube infused glass fibers by single filament fragmentation test methods

    NASA Astrophysics Data System (ADS)

    Roach, Andrew Michael

    Single filament fragmentation tests were completed for individual glass fibers with varying surface treatments and carbon nanostructure infusions. Fiber fragmentation was analyzed by embedding a single filament into a standard tensile interface, which provided shear stress transfer between a conventional epoxy resin system and the constituent filament. Established single filament fragmentation techniques were used to characterize fiber and interface properties. A novel method of comparing fibers is introduced by correlating bundle tow test results to fiber fragmentation critical length data to qualitatively relate fiber performance. Photoelastic birefringent stress fringes were processed at select fiber fragmentation locations to further characterize the fiber-resin, or fiber-carbon nanostructure-resin, interface. Overall, the performance matrix qualitative comparison method, coupled with stress fringe analysis, proved to be an effective means of qualitatively evaluating fiber and processing parameters, and efficiently identifies the most fruitful path forward for optimized fiber development.

  2. Impact strength of a modified continuous glass fiber--poly(methyl methacrylate).

    PubMed

    Vallittu, P K; Narva, K

    1997-01-01

    The effect of fiber reinforcement of autopolymerizing poly(methyl methacrylate) was investigated. The impact strength of continuous E-glass fiber-poly(methyl methacrylate) composite was determined. Rectangular test specimens (n = 10 per group) were modified by incorporating an additional fiber reinforcement of untreated E-glass fibers, silanized E-glass fibers, or aramid fibers in the test specimens. Controls were either unreinforced or reinforced from the middle of the test specimen only. The impact strength of the specimens was measured by using a charpy-type pendulum impact tester after the specimens had been stored in water at 37 degrees C for 4 weeks. After the impact strength test, the length of the delamination of poly(methyl methacrylate) from the fibers was measured and plotted to the impact strength of the test specimens by using a linear regression model. The impact strength of unreinforced autopolymerizing poly(methyl methacrylate) was 7.8 kl/m2, while incorporation of glass fiber reinforcement with a fiber concentration of 12.4 wt% increased the impact strength to 74.7 kl/m2 (P = .000). The additional fiber reinforcement of the test specimen did not affect the impact strength (P = .363). Delamination negatively correlated with the impact strength of the test specimens (r = -.72, P = .000). The results of this study suggest that glass fiber reinforcement enhanced the impact strength of autopolymerizing poly(methyl methacrylate), while the use of additional fiber reinforcement made of aramid or glass fibers in the test specimens did not have an effect on the impact strength. PMID:9206454

  3. Highly tunable interfacial adhesion of glass fiber by hybrid multilayers of graphene oxide and aramid nanofiber.

    PubMed

    Park, Byeongho; Lee, Wonoh; Lee, Eunhee; Min, Sa Hoon; Kim, Byeong-Su

    2015-02-11

    The performance of fiber-reinforced composites is governed not only by the nature of each individual component comprising the composite but also by the interfacial properties between the fiber and the matrix. We present a novel layer-by-layer (LbL) assembly for the surface modification of a glass fiber to enhance the interfacial properties between the glass fiber and the epoxy matrix. Solution-processable graphene oxide (GO) and an aramid nanofiber (ANF) were employed as active components for the LbL assembly onto the glass fiber, owing to their abundant functional groups and mechanical properties. We found that the interfacial properties of the glass fibers uniformly coated with GO and ANF multilayers, such as surface free energy and interfacial shear strength, were improved by 23.6% and 39.2%, respectively, compared with those of the bare glass fiber. In addition, the interfacial adhesion interactions between the glass fiber and the epoxy matrix were highly tunable simply by changing the composition and the architecture of layers, taking advantage of the versatility of the LbL assembly. PMID:25599567

  4. The effect of placement of glass fibers and aramid fibers on the fracture resistance of provisional restorative materials.

    PubMed

    Saygili, Gülbin; Sahmali, Sevil M; Demirel, Figen

    2003-01-01

    The fracture resistance of provisional restorations is an important concern for the restorative dentist. The fracture resistance of a material is directly related to its transverse strength. Six specimens of similar dimensions were prepared from three resins (PMMA, PEMA and BIS acryl-composite). The resins were reinforced with glass and aramid fibers. The samples were tested immediately after the material set, following seven days of wet storage using three-point compression loading. The results were analyzed with an analysis of variance (ANOVA). Fracture resistance of the specimens was statistically different (p < 0.001) among the materials. Specimens reinforced with glass fibers showed higher transverse strength (149.82 MPa). The fiber reinforcement of resin materials increased the strength values (20-50%). Within the limitations of this study, the transverse strengths of PMMA, PEMA and BIS acryl-resin composites were improved after reinforcement with glass and aramid fibers. PMID:12540123

  5. Flexural Strength of Glass and Polyethylene Fiber Combined with Three Different Composites

    PubMed Central

    Sharafeddin, F; Alavi, AA; Talei, Z

    2013-01-01

    Statement of Problem: The flexure of the fiber- reinforced composites (FRC) which can be generally used instead of fixed metal- framework prostheses have been more advocated due to the enormous demands for the conservative and esthetic restoration. The flexure of the fiber should be well-fitted to its covering composite. No study has been reported the comparison of the combination of glass and polyethylene fiber with particulate filled composite and fiber reinforced composite yet. Purpose: This study compared the flexural strength of two types of fibers combined with three types of composites. Materials and Method: Sixty-six specimens were prepared in a split mold (25×2×2 mm). The specimens were divided into six groups according to the type of resin and the fiber (N = 11): group 1: Z250 composite + Polyethylene fiber; group 2: Build It composite + Polyethylene fiber; group 3: Nulite F composite+ Polyethylene fiber; group 4: glass fiber + Z250 composite; group 5: glass fiber + Build-It composite and group 6: glass fiber + Nulite F. The mean flexural strengths (MPa) values were determined in a 3-point bending test at a crosshead speed of 1 mm/min by a universal testing machine (Zwick/Roell Z020, Germany). The results were statistically analyzed, using one and two- way ANOVA and LSD post-hoc tests (p< 0.05). Results: The highest flexural strength was registered for glass fiber in combination with Z250 composite (500 MPa) and the lowest for polyethylene fiber in combination with Build-It composite (188 MPa). One-way ANOVA test revealed that there was no statistically significant difference between polyethylene fiber combinations (p= 0.62) but there was a significant difference between glass fiber combinations (p= 0.0001). Two-way ANOVA revealed that the fiber type had a significant effect on flexural strength (p= 0.0001). Conclusion: The choice of fiber and composite type was shown to have a significant positive influence on the flexural properties of the

  6. Glass fiber processing for the Moon/Mars program: Center director's discretionary fund final report

    NASA Technical Reports Server (NTRS)

    Tucker, D. S.; Ethridge, E.; Curreri, P.

    1992-01-01

    Glass fiber has been produced from two lunar soil simulants. These two materials simulate lunar mare soil and lunar highland soil compositions, respectively. Short fibers containing recrystallized areas were produced from the as-received simulants. Doping the highland simulant with 8 weight percent B2-O3 yielded a material which could be spun continuously. The effects of lunar gravity on glass fiber formation were studied utilizing NASA's KC-135 aircraft. Gravity was found to play a major role in final fiber diameter.

  7. Extrinsic fiber-optic Fabry-Perot interferometer sensor for refractive index measurement of optical glass

    SciTech Connect

    Chen Jihuan; Zhao Jiarong; Huang Xuguang; Huang Zhenjian

    2010-10-10

    A simple fiber-optic sensor based on Fabry-Perot interference for refractive index measurement of optical glass is investigated both theoretically and experimentally. A broadband light source is coupled into an extrinsic fiber Fabry-Perot cavity formed by the surfaces of a sensing fiber end and the measured sample. The interference signals from the cavity are reflected back into the same fiber. The refractive index of the sample can be obtained by measuring the contrast of the interference fringes. The experimental data meet with the theoretical values very well. The proposed technique is a new method for glass refractive index measurement with a simple, solid, and compact structure.

  8. Luminescent glass fiber sensors for ultraviolet radiation detection by the spectral conversion

    NASA Astrophysics Data System (ADS)

    Agafonova, Darina S.; Kolobkova, Elena V.; Ignatiev, Alexander I.; Nikonorov, Nikolay V.; Shakhverdov, Teimur A.; Shirshnev, Pavel S.; Sidorov, Alexander I.; Vasiliev, Vladimir N.

    2015-11-01

    It is shown that glass fibers doped with luminescent molecular clusters of silver, cadmium and lead chalcogenides, or copper (I) can be used for the efficient radiation conversion of ultraviolet (UV) radiation to the visible spectral region. The advantages of radiation trapping in fibers by the luminescent centers and of spectral conversion are discussed. The excitation and luminescence spectra of luminescent fibers are presented. Analysis of application areas of the luminescent glasses and fibers is performed. The construction of the sensitive element for sensor models for electrical spark and UV radiation detection is described. The characteristics of the models of sensors for electrical spark and UV radiation detection are presented.

  9. Impact tensile properties and strength development mechanism of glass for reinforcement fiber

    NASA Astrophysics Data System (ADS)

    Kim, T.; Oshima, K.; Kawada, H.

    2013-07-01

    In this study, impact tensile properties of E-glass were investigated by fiber bundle testing under a high strain rate. The impact tests were performed employing two types of experiments. One is the tension-type split Hopkinson pressure bar system, and the other is the universal high-speed tensile-testing machine. As the results, it was found that not only the tensile strength but also the fracture strain of E-glass fiber improved with the strain rate. The absorbed strain energy of this material significantly increased. It was also found that the degree of the strain rate dependency of E-glass fibers on the tensile strength was varied according to fiber diameter. As for the strain rate dependency of the glass fiber under tensile loading condition, change of the small crack-propagation behaviour was considered to clarify the development of the fiber strength. The tensile fiber strength was estimated by employing the numerical simulation based on the slow crack-growth model (SCG). Through the parametric study against the coefficient of the crack propagation rate, the numerical estimation value was obtained for the various testing conditions. It was concluded that the slow crack-growth behaviour in the glass fiber was an essential for the increase in the strength of this material.

  10. Dispersion engineering in nonlinear soft glass photonic crystal fibers infiltrated with liquids.

    PubMed

    Pniewski, Jacek; Stefaniuk, Tomasz; Van, Hieu Le; Long, Van Cao; Van, Lanh Chu; Kasztelanic, Rafał; Stępniewski, Grzegorz; Ramaniuk, Aleksandr; Trippenbach, Marek; Buczyński, Ryszard

    2016-07-01

    We present a numerical study of the dispersion characteristic modification of nonlinear photonic crystal fibers infiltrated with liquids. A photonic crystal fiber based on the soft glass PBG-08, infiltrated with 17 different organic solvents, is proposed. The glass has a light transmission window in the visible-mid-IR range of 0.4-5 μm and has a higher refractive index than fused silica, which provides high contrast between the fiber structure and the liquids. A fiber with air holes is designed and then developed in the stack-and-draw process. Analyzing SEM images of the real fiber, we calculate numerically the refractive index, effective mode area, and dispersion of the fundamental mode for the case when the air holes are filled with liquids. The influence of the liquids on the fiber properties is discussed. Numerical simulations of supercontinuum generation for the fiber with air holes only and infiltrated with toluene are presented. PMID:27409187

  11. Ultrasonic assisted consolidation of commingled thermoplastic/glass fibers rovings

    NASA Astrophysics Data System (ADS)

    Lionetto, Francesca; Dell'Anna, Riccardo; Montagna, Francesco; Maffezzoli, Alfonso

    2015-04-01

    Thermoplastic matrix composites are finding new applications in different industrial area thanks to their intrinsic advantages related to environmental compatibility and processability. The approach presented in this work consists in the development of a technology for the simultaneous deposition and consolidation of commingled thermoplastic rovings through to the application of high energy ultrasound. An experimental equipment, integrating both fiber impregnation and ply consolidation in a single process, has been designed and tested. It is made of an ultrasonic welder, whose titanium sonotrode is integrated on a filament winding machine. During winding, the commingled roving is at the same time in contact with the mandrel and the horn. The intermolecular friction generated by ultrasound is able to melt the thermoplastic matrix and impregnate the reinforcement fibers. The heat transfer phenomena occurring during the in situ consolidation were simulated solving by finite element (FE) analysis an energy balance accounting for the heat generated by ultrasonic waves and the melting characteristics of the matrix. To this aim, a calorimetric characterization of the thermoplastic matrix has been carried out to obtain the input parameters for the model. The FE analysis has enabled to predict the temperature distribution in the composite during heating and cooling The simulation results have been validated by the measurement of the temperature evolution during ultrasonic consolidation. The reliability of the developed consolidation equipment was proved by producing hoop wound cylinder prototypes using commingled continuous E-glass rovings and Polypropylene (PP) filaments. The consolidated composite cylinders are characterized by high mechanical properties, with values comparable with the theoretical ones predicted by the micromechanical analysis.

  12. Fiber glass prevents cracking of polyurethane foam insulation on cryogenic vessels

    NASA Technical Reports Server (NTRS)

    Forge, D. A.

    1968-01-01

    Fiber glass material, placed between polyurethane foam insulation and the outer surfaces of cryogenic vessels, retains its resilience at cryogenic temperatures and provides an expansion layer between the metal surfaces and the polyurethane foam, preventing cracking of the latter.

  13. Isothermal and hygrothermal agings of hybrid glass fiber/carbon fiber composite

    NASA Astrophysics Data System (ADS)

    Barjasteh, Ehsan

    New applications of fiber-reinforced polymer composites (FRPCs) are arising in non-traditional sectors of industry, such as civil infrastructure, automotive, and power distribution. For example, composites are being used in place of steel to support high-voltage overhead conductors. In this application, conductive strands of aluminum are wrapped around a solid composite rod comprised of unidirectional carbon and glass fibers in an epoxy matrix, which is commercially called ACCC conductor. Composite-core conductors such as these are expected to eventually replace conventional steel-reinforced conductors because of the reduced sag at high temperatures, lower weight, higher ampacity, and reduced line losses. Despite the considerable advantages in mechanical performance, long-term durability of composite conductors is a major concern, as overhead conductors are expected to retain properties (with minimal maintenance) over a service life that spans multiple decades. These concerns stem from the uncertain effects of long-term environmental exposure, which includes temperature, moisture, radiation, and aggressive chemicals, all of which can be exacerbated by cyclic loads. In general, the mechanical and physical properties of polymer composites are adversely affected by such environmental factors. Consequently, the ability to forecast changes in material properties as a function of environmental exposure, particularly bulk mechanical properties, which are affected by the integrity of fiber-matrix interfaces, is required to design for extended service lives. Polymer composites are susceptible to oxidative degradation at high temperatures approaching but not quite reaching the glass transition temperature ( Tg). Although the fibers are stable at such temperatures, the matrix and especially the fiber-matrix interface can undergo degradation that affects the physical and mechanical properties of the structure over time. Therefore, as a first step, the thermal aging of an

  14. Single-frequency fiber oscillator with watt-level output power using photonic crystal phosphate glass fiber.

    PubMed

    Schülzgen, A; Li, L; Temyanko, V L; Suzuki, S; Moloney, J V; Peyghambarian, N

    2006-08-01

    Utilizing phosphate glass fiber with photonic crystal cladding and highly doped, large area core a cladding-pumped, single-frequency fiber oscillator is demonstrated. The fiber oscillator contains only 3.8 cm of active fiber in a linear cavity and operates in the 1.5 micron region. Spectrally broad, multimode pump light from semiconductor laser diodes is converted into a single-mode, single-frequency light beam with an efficiency of about 12% and the oscillator output power reached 2.3 W. PMID:19529079

  15. Separator for starved electrolyte lead/acid battery. [perlite and glass fiber mixture

    SciTech Connect

    Bilawsky, P.D.; Cain, C.W.; Gross, S.E.; Scheffel, N.B.

    1980-11-11

    Compositions and papers made therefrom useful as separator materials in starved electrolyte lead/acid batteries are described. The compositions comprise a mixture of 30% to 80% by weight of perlite and 20% to 70% by weight of glass fibers. The glass fibers have diameters in the range of from 0.3 to 1.0 micrometers while the perlite has particle sizes in the range of from about 3 to about 100 micrometers.

  16. Feasibility research report of villa constructed of glass fiber reinforced concrete

    NASA Astrophysics Data System (ADS)

    Li, Shengli; Lu, Yu; Wang, Dongwei

    2011-04-01

    With the development of economy and improvement degree of modernization, the villa project design program tend to focus on the green, high-tech, humanities, and more emphasis on the integrity of space, noble and elegant feeling. Therefore, based on the study of literatures, this paper discussed the present situation and issue and features of Glass Fiber Reinforced Concrete and the feature of assembly house, and confirmed that the villa of assemble house is feasible by built of Glass Fiber Reinforced Concrete.

  17. Three-Year Follow Up of Customized Glass Fiber Esthetic Posts

    PubMed Central

    da Costa, Rogério Goulart; de Morais, Eduardo Christiano Caregnatto; Leão, Moira Pedroso; Bindo, Márcio José Fraxino; Campos, Edson Alves; Correr, Gisele Maria

    2011-01-01

    Customized glass fiber posts that is well adjusted into the root canal and have mechanical properties similar to those of dentin may be a suitable treatment for severely compromised endodontically treated teeth. This article reports a 3-year follow up of severely damaged endodontically treated teeth restored with unidirectional fiber glass customized post and core system instead of a conventional fiber post. The fabrication of this glass fiber customized post is a simple technique, providing an increased volume of fibers into the root canal, and an adequate polymerization of the post-core system. Over a three-year period, the treatments demonstrated good clinical and radiographic characteristics, with no fracture or loss of the post and/or crown. This technique can be considered effective, less invasive, and suitable for restore endodontically treated teeth. PMID:21228960

  18. Method of producing a ceramic fiber-reinforced glass-ceramic matrix composite

    NASA Technical Reports Server (NTRS)

    Bansal, Narottam P. (Inventor)

    1994-01-01

    A fiber-reinforced composite composed of a BaO-Al2O3-2SiO2 (BAS) glass ceramic matrix is reinforced with CVD silicon carbide continuous fibers. A slurry of BAS glass powders is prepared and celsian seeds are added during ball melting. The slurry is cast into tapes which are cut to the proper size. Continuous CVD-SiC fibers are formed into mats of the desired size. The matrix tapes and the fiber mats are alternately stacked in the proper orientation. This tape-mat stack is warm pressed to produce a 'green' composite. The 'green' composite is then heated to an elevated temperature to burn out organic constituents. The remaining interim material is then hot pressed to form a silicon carbide fiber-reinforced celsian (BAS) glass-ceramic matrix composite which may be machined to size.

  19. The effect of exposed glass fibers and particles of bioactive glass on the surface wettability of composite implants.

    PubMed

    Abdulmajeed, Aous A; Lassila, Lippo V; Vallittu, Pekka K; Närhi, Timo O

    2011-01-01

    Measurement of the wettability of a material is a predictive index of cytocompatibility. This study was designed to evaluate the effect of exposed E-glass fibers and bioactive glass (BAG) particles on the surface wettability behavior of composite implants. Two different groups were investigated: (a) fiber reinforced composites (FRCs) with different fiber orientations and (b) polymer composites with different wt. % of BAG particles. Photopolymerized and heat postpolymerized composite substrates were made for both groups. The surface wettability, topography, and roughness were analyzed. Equilibrium contact angles were measured using the sessile drop method. Three liquids were used as a probe for surface free energy (SFE) calculations. SFE values were calculated from contact angles obtained on smooth surfaces. The surface with transverse distribution of fibers showed higher (P < 0.001) polar (γ(P)) and total SFE (γ(TOT)) components (16.9 and 51.04 mJ/m(2), resp.) than the surface with in-plane distribution of fibers (13.77 and 48.27 mJ/m(2), resp.). The increase in BAG particle wt. % increased the polar (γ(P)) value, while the dispersive (γ(D)) value decreased. Postpolymerization by heat treatment improved the SFE components on all the surfaces investigated (P < 0.001). Composites containing E-glass fibers and BAG particles are hydrophilic materials that show good wettability characteristics. PMID:22253628

  20. Electroless silver plating on tetraethoxy silane-bridged fiber glass

    NASA Astrophysics Data System (ADS)

    Lien, Wan-Fu; Huang, Po-Chen; Tseng, Shi-Chang; Cheng, Chia-Hsiang; Lai, Shih-Ming; Liaw, Wen-Chang

    2012-01-01

    Tetraethoxy silane was used to functionalize the surface of fiber glass (FG) for adsorption with the electroless plated silver shell. The performance of electroless silver plated FG with tetraethoxy silane modification was compared to that of unmodified FG in terms of mechanical and electrical properties. The silane bridge provided more stability for binding with different concentrations of electroless plating silver ions. The characterization was investigated by using field emission scanning electron microscope (FESEM), X-ray diffraction patterns (XRD), energy-dispersion X-ray (EDX), metal microscope (MM) and electric resistance. The Ag coating on TEOS modified FG was more durable than that of unmodified FG in the ball milling test, as confirmed by the data of electric resistance and residue weight. The optimized conditions for producing the Ag coating FG were also investigated. The Ag-Si-FG-3-c product in this study has the lowest electrical resistance of 1.56 × 103 Ω/cm2 and good mechanical stability as exhibited in ball milling tests.

  1. High-Strength / High Alkaline Resistant Fe-Phosphate Glass Fibers as Concrete Reinforcement

    SciTech Connect

    Mariano Velez

    2008-03-31

    Calcium-iron-phosphate glasses were developed whose chemical durabilities in alkaline solutions (pH 13) were comparable or superior to those of commercial alkaline-resistant (AR) silica-based glasses. However, the tensile strength of Ca-Fe-phosphate fibers, after being exposed to alkaline environments, including wet Portland cement pastes, is lower than that of current AR silicate fibers. Another series of Ca-Fe-phosphate glasses were developed with excellent chemical durability in strong acidic solutions (H2SO4, HF), indicating potential applications where silica-based fibers degrade very quickly, including E-glass. The new Ca-Fe-phosphate glasses can be melted and processed 300 to 500°C lower than silica-based glasses. This offers the possibility of manufacturing glass fibers with lower energy costs by 40-60% and the potential to reduce manufacturing waste and lower gas emissions. It was found that Ca-Fe-phosphate melts can be continuously pulled into fibers depending on the slope of the viscosity-temperature curve and with viscosity ~100 poise, using multi-hole Pt/Rh bushings.

  2. The recycling of comminuted glass-fiber-reinforced resin from electronic waste.

    PubMed

    Duan, Huabo; Jia, Weifeng; Li, Jinhui

    2010-05-01

    The reuse of comminuted glass-fiber-reinforced resin with various granularities gathered from printed circuit manufacturing residues was investigated. As fillers, these residues were converted into polymeric composite board by an extrusion and injection process using polypropylene as a bonding agent. The mechanical properties of the reproduced composite board were examined by considering the effects of mass fraction and glass-fiber distribution. Interfacial-layer micrograph analysis of the composite material fracture surface was used to study the fiber reinforcement mechanism. Results showed that using comminuted glass-fiber-reinforced resin as a filler material greatly enhanced the performance properties of the composite board. Although the length and diameter of filler varied, these variations had no appreciable effect on the mechanical properties of the processed board. Maximum values of 48.30 MPa for flexural strength, 31.34 MPa for tensile strength, and 31.34 J/m for impact strength were achieved from a composite board containing mass fractions of 30, 10, and 20% glass-fiber-reinforced resin waste, respectively. It was found that the maximum amount of recyclate that could be added to a composite board was 30% of weight. Beyond these percentages, the materials blend became unmanageable and the mixture less amenable to impregnation with fiber. Presented studies indicated that comminuted glass-fiber-reinforced resin waste-filled polypropylene composites are promising candidates for structural applications where high stiffness and fracture resistance are required. PMID:20480852

  3. The microstructure of erbium-ytterbium co-doped oxyfluoride glass-ceramic optical fibers

    NASA Astrophysics Data System (ADS)

    Augustyn, Elżbieta; Żelechower, Michał; Stróż, Danuta; Chrapoński, Jacek

    2012-04-01

    Oxyfluoride transparent glass-ceramics combine some features of glasses (easier shaping or lower than single crystals cost of fabrication) and some advantages of rare-earth doped single crystals (narrow absorption/emission lines and longer lifetimes of luminescent levels). Since the material seems to be promising candidate for efficient fiber amplifiers, the manufacturing as well as structural and optical examination of the oxyfluoride glass-ceramic fibers doped with rare-earth ions seems to be a serious challenge. In the first stage oxyfluoride glasses of the following compositions 48SiO2-11Al2O3-7Na2CO3-10CaO-10PbO-11PbF2-3ErF3 and 48SiO2-11Al2O3-7Na2CO3-10CaO-10PbO-10PbF2-3YbF3-1ErF3 (in molar%) were fabricated from high purity commercial chemicals (Sigma-Aldrich). The fabricated glass preforms were drawn into glass fibers using the mini-tower. Finally, the transparent Er3+ doped and Er3+/Yb3+ co-doped oxyfluoride glass-ceramic fibers were obtained by controlled heat treatment of glass fibers. The preceding differential thermal analysis (DTA) studies allowed estimating both the fiber drawing temperature and the controlled crystallization temperature of glass fibers. X-ray diffraction examination (XRD) at each stage of the glass-ceramic fibers fabrication confirmed the undesirable crystallization of preforms and glass fibers has been avoided. The fibers shown their mixed amorphous-crystalline microstructure with nano-crystals of size even below 10 nm distributed in the glassy host. The crystal structure of the grown nano-crystals has been determined by XRD and confirmed by electron diffraction (SAED). Results obtained by both techniques seem to be compatible: Er3FO10Si3 (monoclinic; ICSD 92512), Pb5Al3F19 (triclinic; ICSD 91325) and Er4F2O11Si3 (triclinic; ICSD 51510) against to initially expected PbF2 crystals.

  4. Preparation and investigation of Ge-S-I glasses for infrared fiber optics

    NASA Astrophysics Data System (ADS)

    Velmuzhov, A. P.; Sukhanov, M. V.; Plekhovich, A. D.; Snopatin, G. E.; Churbanov, M. F.; Iskhakova, L. D.; Ermakov, R. P.; Kotereva, T. V.; Shiryaev, V. S.

    2016-02-01

    Glass samples of [GeSx]90I10 (x = 1.5, 1.7, 2.0, 2.3, 2.45, 2.6) compositions were prepared, and some their thermal, optical properties as well as tendency to crystallization were investigated. The compositional dependences of glass transition temperature, volume fraction of crystallized phase and activation energy of glass formation (Eg) have nonmonotonic character with a maximum for [GeS2.0]90I10 glass. Glasses of 85.8GeS2-14.2GeI4 and [GeS1.5]90I10 compositions are identified as promising for preparation of optical fiber. For the first time, Ge-S-I glass fibers were produced. Minimum optical losses in 85.8GeS2-14.2GeI4 glass fiber were 2.7 dB/m at a wavelength of 5.1 μm, and that in [GeS1.5]90I10 glass fiber were 14.5 dB/m at 5.5 μm.

  5. In vivo and in vitro studies of borate based glass micro-fibers for dermal repairing.

    PubMed

    Zhou, Jie; Wang, Hui; Zhao, Shichang; Zhou, Nai; Li, Le; Huang, Wenhai; Wang, Deping; Zhang, Changqing

    2016-03-01

    Full-thickness skin defects represent urgent clinical problem nowadays. Wound dressing materials are hotly needed to induce dermal reconstruction or to treat serious skin defects. In this study, the borate bioactive glass (BG) micro-fibers were fabricated and compared with the traditional material 45S5 Bioglass(®) (SiG) micro-fibers. The morphology, biodegradation and bioactivity of BG and SiG micro-fibers were investigated in vitro. The wound size reduction and angiogenic effects of BG and SiG micro-fibers were evaluated by the rat full-thickness skin defect model and Microfil technique in vivo. Results indicated that the BG micro-fibers showed thinner fiber diameter (1 μm) and better bioactivity than the SiG micro-fibers did. The ionic extracts of BG and SiG micro-fibers were not toxic to human umbilical vein endothelial cells (HUVECs). In vivo, the BG micro-fiber wound dressings obviously enhanced the formation of blood vessel, and resulted in a much faster wound size reduction than the SiG micro-fibers, or than the control groups, after 9 days application. The good skin defect reconstruction ability of BG micro-fibers contributed to the B element in the composition, which results in the better bioactivity and angiogenesis. As shown above, the novel bioactive borate glass micro-fibers are expected to provide a promising therapeutic alternative for dermal reconstruction or skin defect repair. PMID:26706550

  6. Effect of winding layer and speed on kenaf/glass fiber hybrid reinforced acrylonitrile butadiene styrene (ABS) composites

    NASA Astrophysics Data System (ADS)

    Khoni, Norizzahthul Ainaa Abdul; Sharifah Shahnaz S., B.; Ghazali, Che Mohd Ruzaidi

    2016-07-01

    The usage of natural fiber is becoming significant in composite industries due to their good performance. Single and continuous natural fibers have relatively high mechanical properties; especially their young modulus can be as high as glass fibers. Filament winding is a method to produce technically aligned composites which have high fibers content. The properties of filament winding can be tailored to meet the end product requirements. This research studied the compression properties of kenaf/glass fibers hybrid reinforced composites. Kenaf/glass fibers hybrid composite samples were fabricated by filament winding technique and their properties were compared with the properties of neat kenaf fiber and glass fibers composites. The kenaf/glass fiber hybrid composites exhibited higher strength compared to the neat glass fibers composites. Composites of helical pattern, which produced at low winding speed showed better compression resistance than hoop pattern winding, which produced at high winding speed. As predicted, kenaf composite showed highest water absorption; followed by kenaf/glass fiber hybrid composites while neat glass fiber has lowest water absorption capability.

  7. Modifying glass fiber surface with grafting acrylamide by UV-grafting copolymerization for preparation of glass fiber reinforced PVDF composite membrane.

    PubMed

    Luo, Nan; Zhong, Hui; Yang, Min; Yuan, Xing; Fan, Yaobo

    2016-01-01

    Experimental design and response surface methodology (RSM) were used to optimize the modification of conditions for glass surface grafting with acrylamide (AM) monomer for preparation of a glass fiber reinforced poly(vinylidene fluoride) (PVDF) composite membrane (GFRP-CM). The factors considered for experimental design were the UV (ultraviolet)-irradiation time, the concentrations of the initiator and solvent, and the kinds and concentrations of the silane coupling agent. The optimum operating conditions determined were UV-irradiation time of 25 min, an initiator concentration of 0-0.25 wt.%, solvent of N-Dimethylacetamide (DMAC), and silane coupling agent KH570 with a concentration of 7 wt.%. The obtained optimal parameters were located in the valid region and the experimental confirmation tests conducted showed good accordance between predicted and experimental values. Under these optimal conditions, the water absorption of the grafted modified glass fiber was improved from 13.6% to 23%; the tensile strength was enhanced and the peeling strength of the glass fiber reinforced PVDF composite membrane was improved by 23.7% and 32.6% with an AM concentration at 1 wt.% and 2 wt.%. The surface composition and microstructure of AM grafted glass fiber were studied via several techniques including Field Emission Scanning Electron Microscopy (FESEM), Fourier transform infrared spectroscopy-attenuated total reflectance (FTIR-ATR) and energy dispersive X-ray spectroscopy (EDX). The analysis of the EDX and FTIR-ATR results confirmed that the AM was grafted to the glass fiber successfully by detecting and proving the existence of nitrogen atoms in the GFRP-CM. PMID:26899659

  8. Bismuth-doped-glass optical fibers--a new active medium for lasers and amplifiers.

    PubMed

    Dvoyrin, V V; Mashinsky, V M; Bulatov, L I; Bufetov, I A; Shubin, A V; Melkumov, M A; Kustov, E F; Dianov, E M; Umnikov, A A; Khopin, V F; Yashkov, M V; Guryanov, A N

    2006-10-15

    Optical fibers with bismuth-doped silicate and germanate glass cores were fabricated by the modified chemical vapor deposition technique (solution and vapor-phase Bi incorporation). The fibers revealed an efficient luminescence with a maximum in the 1050-1200 nm spectral range, FWHM up to 200 nm, and a lifetime of the order of 1 ms. PMID:17001368

  9. Progress in heavy metal fluoride glasses for infrared fibers

    NASA Astrophysics Data System (ADS)

    Drexhage, M. G.; El-Bayoumi, O. H.; Moynihan, C. T.

    1982-12-01

    The optical and physical characteristics of heavy metal fluoride glasses are reviewed with reference to recent laboratory experiments. In particular, attention is given to comparative optical studies of fluorozirconate and fluorohafnate glasses, refractive index and material dispersion of fluoride glasses, and preliminary results of optical studies of heavy metal fluoride glasses not containing ZrF4 or HfF4. The latter sometimes exhibit extended transparency in the mid-IR relative to that observed in fluorozirconate and fluorohafnate glasses. The effect of the AlF4 content on the optical properties of BaF2/ThF4 glasses is discussed.

  10. Analysis of biological and chemical compounds by remote spectroscopy using IR TeX glass fibers

    NASA Astrophysics Data System (ADS)

    Le Foulgoc, Karine; Le Neindre, Lydia; Guimond, Yann; Ma, Hong Li; Zhang, Xhang H.; Lucas, Jacques

    1995-09-01

    The TeX glasses are attracting much attention as materials for low loss mid-IR optical fibers and are consequently good candidates for thermal imaging, laser power delivery, and more recently remote sensing. The TeX glass fiber, transmitting in a wide optical window, has a minimum attenuation in the 9-10 micrometers region. Fibers with an attenuation of less than 0.5 dB/m have been repeatly obtained. These fibers are coated with a UV curable or thermal plastic, in order to improve their mechanical properites. The IR remote spectroscopy using TeX fibers is one of the most promising applications. This technology allows to perform in situ, real-time, and on-line analysis of chemical and biological compounds. The study of industrial processes such as fermentations has been performed by this method, based on the use of these IR TeX fibers.

  11. Influence of drawing conditions on the properties of bismuth borate glass fibers

    NASA Astrophysics Data System (ADS)

    Walker, Juergen

    In this study the influence of forming conditions, namely draw temperature and draw speed, on thermal properties of glass fibers of the composition 0.25 Bi2O3--0.75 B2O 3 were examined using mainly DSC measurements and confocal micro---Raman spectroscopy. Glass fibers were drawn at temperatures of 525, 550 and 575°C and draw speeds ranging from 1 to 10 m/sec. DSC measurements were performed to measure glass transition, heat capacity, fictive temperature, and pre--T g exotherm, both in strength and the onset. Concurrently micro---Raman measurements were used to identify the structural borate groups present in the fibers and their change with forming conditions. Several trends could be observed. As draw speed increases the glass transition decreases, indicating a more disordered structure. Pre--Tg exotherms show a local maximum at draw speeds of 4 m/s. Raman spectroscopy indicates the presence of [BiO6] octahedra that are becoming more distorted as the draw speed increases. The local maximum in both the pre--Tg exotherm and the corresponding Raman peak show that there is an optimal distortion. Pre--T g exotherm onset temperatures show a linear decrease with draw speeds. All this supports the conclusion that there is no major structural rearrangement. Heat capacity shows no overall trends of behavior dependant on forming conditions. These glass fibers also show a decrease in glass transition height during reheating that indicates a decreasing amount of glass. This can either be due to crystallization or phase separation. Finally the aspect ratio of the glass fibers seems to have a direct influence on heat capacity. As the aspect ratio increases the heat capacity of the glass fibers increases suddenly by a factor of two. The exact mechanism for this effect is unclear at this point.

  12. Effect of temperature and fiber coating on the strength of E-glass fibers and the E-glass/epoxy interface for single-fiber fragmentation samples immersed in water

    SciTech Connect

    Schultheisz, C.R.; Schutte, C.L.; McDonough, W.G.; Macturk, K.S.; McAuliffe, M.; Kondagunta, S.; Huntson, D.L.

    1996-12-31

    The effect of absorbed moisture on the strengths of fibers and the fiber/matrix interface for an epoxy reinforced with continuous fibers of E-glass is under investigation. Single-fiber fragmentation tests of glass/epoxy model composites have shown degradation of the strengths of both the fiber and the interface after immersion in water. The fragmentation specimens were tested as-fabricated and after immersion in distilled water at 25 and 75 C for more than 4000 h. Two coatings were applied to the fibers, one epoxy-compatible and the other vinylester-compatible, in an effort to include the initial interfacial shear strength as a variable. Analyses of the fragmentation test results adapting the approach of Wagner and coworkers were used to determine moisture-induced changes in the fiber strength, making it possible to also evaluate changes in the interfacial strength.

  13. Radiation hardening of strengthened optical fibers and development of new fluoride glasses

    NASA Astrophysics Data System (ADS)

    Mohr, R. K.; Simmons, J. H.; Moynihan, C. T.; Barkatt, A.; Hojaji, H.; Williams, C.; Boulos, M. S.; Gbogi, E. O.; Chung, K. H.

    1982-04-01

    Two independent studies were conducted under this contract: (1) Radiation hardening of compressively strengthened optical fibers; (2) Development of new fluoride glasses. In the first study two preform fabrication processes based on phase separable, leachable alkali borosilicate glasses were evaluated for producing radiation hardened fibers. The first process, known as partial leaching, was found to yield low numerical aperture fibers with moderately high attenuation. Ultra-clean glass melting facilities and extensive composition studies would be required to correct these faults. This was beyond the resources of the contract. The second process, known as molecular stuffing, was used to produce alkali-modified high silica glasses doped with cerium oxide as a radiation hardening agent. Radiation damage kinetic tests were run on these glasses by irradiating the samples with 4-40 ns pulses of 15 MeV electrons and observing the absorption spectra for the time range 0.0000001 sec to 0.1 sec following the electron pulses. The results of these tests show that cerium is not effective, within the time range studies, in suppressing the radiation induced absorption for the high silica glasses tested. In the second study, under this contract, glasses in the HfF4-BaF2-LaF3 family were studied. The effects on glass forming of additions including PbF2, CsF, GdF3 and AlF3 glass was studied.

  14. Process for Converting Waste Glass Fiber into Value Added Products, Final Report

    SciTech Connect

    Hemmings, Raymond T.

    2005-12-31

    Nature of the Event: Technology demonstration. The project successfully met all of its technical objectives. Albacem has signed an exclusive licensing agreement with Vitro Minerals Inc., a specialty minerals company, to commercialize the Albacem technology (website: www.vitrominerals.com). Location: The basic research for the project was conducted in Peoria, Illinois, and Atlanta, Georgia, with third-party laboratory verification carried out in Ontario, Canada. Pilot-scale trials (multi-ton) were conducted at a facility in South Carolina. Full-scale manufacturing facilities have been designed and are scheduled for construction by Vitro Minerals during 2006 at a location in the Georgia, North Carolina, and South Carolina tri-state area. The Technology: This technology consists of a process to eliminate solid wastes generated at glass fiber manufacturing facilities by converting them to value-added materials (VCAS Pozzolans) suitable for use in cement and concrete applications. This technology will help divert up to 250,000 tpy of discarded glass fiber manufacturing wastes into beneficial use applications in the concrete construction industry. This technology can also be used for processing glass fiber waste materials reclaimed from monofills at manufacturing facilities. The addition of take-back materials and reclamation from landfills can help supply over 500,000 tpy of glass fiber waste for processing into value added products. In the Albacem process, waste glass fiber is ground to a fine powder that effectively functions as a reactive pozzolanic admixture for use in portland ce¬ment-based building materials and products, such as concrete, mortars, terrazzo, tile, and grouts. Because the waste fiber from the glass manufacturing industry is vitreous, clean, and low in iron and alkalis, the resulting pozzolan is white in color and highly consistent in chemical composition. This white pozzolan, termed VCAS Pozzolan (for Vitreous Calcium-Alumino-Silicate). is

  15. Laser Pattern Profile Emitted through Optical Glass Fiber Bundle with Load

    NASA Astrophysics Data System (ADS)

    Yamauchi, Toshihiko

    2004-09-01

    The output pattern of a He-Ne laser that passes through an optical glass fiber bundle depends on the weight of load put on the fiber. The increment of the pattern radius exponentially increases with the load. It is considered that the bending of the fiber causes this increment. The estimated delay time also exponentially increases with the weight of the load, and the estimated delay time by the load and the bending is on the order of picosecond.

  16. Diamagnetic tellurite glass and fiber based magneto-optical current transducer.

    PubMed

    Chen, Qiuling; Ma, Qiuhua; Wang, Hui; Chen, Qiuping

    2015-10-10

    Diamagnetic TeO2-ZnO-Na2O glasses and fibers were fabricated and characterized for magneto-optical current-sensor applications. Two prototypes based on the obtained glass and fibers were constructed. An analysis of the distribution of the magnetic field flux inside the conductor was performed. Hardware and developed software were constructed for the acquisition of weak output signals induced by a low current. The good sensitivities of the fiber magneto-optical current transducer and the bulk magneto-optical current transducer are due to the high Verdet constant and homemade signal-acquisition hardware. PMID:26479801

  17. PNNL/Euratom glass fiber optic, spent fuel neutron profile measurement system

    SciTech Connect

    SM Bowyer; JE Smart

    2000-03-03

    The glass fiber optic spent fuel neutron profile measurement system is designed to measure the neutron profile of a Castor with high reproducibility and to distinguish spent fuel Castor contents from vitrified waste Castor contents. The basic principle of the detector is that the glass fibers detect thermal neutrons. The glass is loaded with lithium enriched in Li-6, which has a high thermal neutron cross-section. A neutron is captured by the Li-6 and a He-4 and H-3 are created. Because the glass also contains Cerium in a 3{sup +} ionization state, the excitation caused by the movement of the He-4 and H-3 results in the emission of light from the cerium atoms. This light then travels to the ends of the fiber where it is detected by photon sensitive devices (e.g., photo-multiplier tubes).

  18. Silicate all-solid photonic crystal fibers with a glass high index contrast

    NASA Astrophysics Data System (ADS)

    Buczynski, Ryszard; Pysz, Dariusz; Kujawa, Ireneusz; Fita, Piotr; Pawlowska, Monika; Nowosielski, J.; Radzewicz, Czeslaw; Stepien, Ryszard

    2007-05-01

    An all-solid photonic crystal fiber can be developed using two thermally matched glasses with one glass forming the background, and the other the lattice of inclusions. Optical properties of all-solid holey fibers (SOHO) are sensitive to the photonic cladding configuration, much the same as PCFs with air holes, and strongly depend on dispersion properties of the materials used. When a high index contrast between the glasses is assured photonic crystal fiber can effectively guide light with photonic band gap mechanism. This can be easily achieved when multicomponent soft glass is used for fiber fabrication. We report on new developments of F2/NC-21 silicate all-glass PCFs. F2 is a commercially available glass (Schott Inc.) with a high concentration of lead-oxide (PbO=45.5%) and the refractive index n D=1.619. It can be used both as the background material and as a material for micro-rods (inclusions). A borosilicate glass (B IIO 3=26.0%) NC-21 glass has been synthesized in-house at IEMT. NC21 has the index n D=1.533 and was used as the material for micro-rods (inclusions) or as a background glass in the structures. The two selected glasses have a high index contrast equal to 0,084 at 1,55μm wavelength. In this report we present new results on optimization of the filling factor d/Λ and reduction of the lattice pitch Λ necessary to obtain efficient guidance at 1.55 μm. The numerical analysis of SOHO F2/NC21 fibers has been carried out using a full-vector mode solver based on the plane-wave expansion method. In our paper we report on photonic crystal fibers with two guiding mechanisms: an effective index with a high index core (low index inclusions made of NC21 glass and F2 used as a background glass) and a photonic band gap with a low index core (high index inclusions made of F2 glass and NC21 used as a background glass).

  19. Energy Saving Method of Manufacturing Ceramic Products from Fiber Glass Waste

    SciTech Connect

    Michael J. Haun

    2005-07-15

    The U.S. fiber glass industry disposes of more than 260,000 tons of industrial fiber glass waste in landfills annually. New technology is needed to reprocess this industrial waste into useful products. A low-cost energy-saving method of manufacturing ceramic tile from fiber glass waste was developed. The technology is based on sintering fiber glass waste at 700-900 degrees C to produce products which traditionally require firing temperatures of >1200 degrees C, or glass-melting temperatures >1500 degrees C. The process also eliminates other energy intensive processing steps, including mining and transportation of raw materials, spray-drying to produce granulated powder, drying pressed tile, and glazing. The technology completely transforms fiber glass waste into a dense ceramic product, so that all future environmental problems in the handling and disposal of the fibers is eliminated. The processing steps were developed and optimized to produce glossy and matte surface finishes for wall and floor tile applications. High-quality prototype tile samples were processed for demonstration and tile standards testing. A Market Assessment confirmed the market potential for tile products produced by the technology. Manufacturing equipment trials were successfully conducted for each step of the process. An industrial demonstration plant was designed, including equipment and operating cost analysis. A fiber glass manufacturer was selected as an industrial partner to commercialize the technology. A technology development and licensing agreement was completed with the industrial partner. Haun labs will continue working to transfer the technology and assist the industrial partner with commercialization beyond the DOE project.

  20. Pulmonary deposition and clearance of glass fiber in rat lungs after long-term inhalation.

    PubMed Central

    Tanaka, I; Oyabu, T; Ishimatsu, S; Hori, H; Higashi, T; Yamato, H

    1994-01-01

    In this study Wistar male rats were exposed to glass fiber obtained by the disintegration of a binderless glass fiber filter, for 6 hr/day, 5 days/week for 12 months. The mass median aerodynamic diameter (MMAD) of the fiber, determined with an Andersen sampler, was 2.6 microns. The count median diameter and length of the fibers measured by scanning electron microscopy (SEM) were 0.51 and 5.5 microns, respectively. The daily average exposure fiber concentration was 2.2 +/- 0.6 mg/m3. Some rats were sacrificed 24 hr after removal from the exposure chamber following the 12 months' exposure. Others were sacrificed 12 months after the end of exposure. The wet organ weights were recorded at the time of death and the silicon content of the lungs was determined by absorption spectrophotometry. After 12 months' exposure, the amount of glass fiber retained in the rat lungs was 1.49 mg, and after 12 months' clearance it was 0.61 mg. The biological half-life in a single exponential model was to be 8.7 months, much longer than the predicted value of 1.5 months obtained in a previous experiment in which rats were exposed for 4 weeks to the same glass fiber. PMID:7882935

  1. Influence of the interface and fiber spacing on the fracture behavior of glass matrix composites

    SciTech Connect

    Matikas, T.E.; Karpur, P.; Kim, R.; Dutton, R.

    1995-09-01

    In this work, a nondestructive methodology is provided to determine the presence of microcracking in unidirectional SiC fiber reinforced brittle (borosilicate glass) matrix composites and to detect internal cracks in the composites that did not reach the surface of the specimen. The methodology is based on a combination of several ultrasonic techniques including shear back reflectivity (SBR), back-reflected surface wave imaging and acoustic microscopy. The composites used in this study were made with controlled fiber spacing consisting of regular arrays of either TiB{sub 2} coated SIGMA 1240 or carbon coated SCS-6 monofilament fibers in a series of borosilicate glasses. The combinations of different constituents provided composite samples with various fiber matrix interface properties. The composites were subjected to axial loading, and the stress in the composite when matrix cracking first occurs was determined and compared with theoretical values provided by a semi-empirical model which can assume either a completely bonded (i.e. perfect) or completely unbonded (i.e. pure slip) fiber-matrix interface. Results from the tensile data for different glass matrix composite systems were also compared with data of interface elastic property evaluation using ultrasonic SBR technique, allowing investigation f the influence of the fiber-matrix interface elastic property, the volume fraction of the fibers, and the state of radial residual stresses at the interface on the fracture behavior of glass matrix composites.

  2. Flexural Strength Comparison of Silorane- and Methacrylate-Based Composites with Pre-impregnated Glass Fiber

    PubMed Central

    Doozandeh, Maryam; Alavi, Ali Asghar; Karimizadeh, Zahra

    2016-01-01

    Statement of the Problem Sufficient adhesion between silorane/methacrylate-based composites and methacrylate impregnated glass fiber increases the benefits of fibers and enhances the mechanical and clinical performance of both composites. Purpose The aim of this study was to evaluate the compatibility of silorane and methacrylate-based composites with pre-impregnated glass fiber by using flexural strength (FS) test. Materials and Method A total of 60 bar specimens were prepared in a split mold (25×2×2 mm) in 6 groups (n=10). In groups 1 and 4 (control), silorane-based (Filtek P90) and nanohybrid (Filtek Z350) composites were placed into the mold and photopolymerized with a high-intensity curing unit. In groups 2 and 5, pre-impregnated glass fiber was first placed into the mold and after two minutes of curing, the mold was filled with respective composites. Prior to filling the mold in groups 3 and 6, an intermediate adhesive layer was applied to the glass fiber. The specimens were stored in distilled water for 24 hours and then their flexural strength was measured by 3 point bending test, using universal testing machine at the crosshead speed of 1 mm/min. Two-way ANOVA and post-hoc test were used for analyzing the data (p< 0.05). Results A significant difference was observed between the groups (p< 0.05). The highest FS was registered for combination of Z350 composite, impregnated glass fiber, and application of intermediate adhesive layer .The lowest FS was obtained in Filtek P90 alone. Cohesive failure in composite was the predominant failure in all groups, except group 5 in which adhesive failure between the composite and fiber was exclusively observed. Conclusion Significant improvement in FS was achieved for both composites with glass fiber. Additional application of intermediate adhesive layer before composite build up seems to increase FS. Nanohybrid composite showed higher FS than silorane-based composite. PMID:27284555

  3. Hierarchical composite structures prepared by electrophoretic deposition of carbon nanotubes onto glass fibers.

    PubMed

    An, Qi; Rider, Andrew N; Thostenson, Erik T

    2013-03-01

    Carbon nanotube/glass fiber hierarchical composite structures have been produced using an electrophoretic deposition (EPD) approach for integrating the carbon nanotubes (CNTs) into unidirectional E-glass fabric, followed by infusion of an epoxy polymer matrix. The resulting composites show a hierarchical structure, where the structural glass fibers, which have diameters in micrometer range, are coated with CNTs having diameters around 10-20 nm. The stable aqueous dispersions of CNTs were produced using a novel ozonolysis and ultrasonication technique that results in dispersion and functionalization in a single step. Ozone-oxidized CNTs were then chemically reacted with a polyethyleneimine (PEI) dendrimer to enable cathodic EPD and promote adhesion between the CNTs and the glass-fiber substrate. Deposition onto the fabric was accomplished by placing the fabric in front of the cathode and applying a direct current (DC) field. Microscopic characterization shows the integration of CNTs throughout the thickness of the glass fabric, where individual fibers are coated with CNTs and a thin film of CNTs also forms on the fabric surfaces. Within the composite, networks of CNTs span between adjacent fibers, and the resulting composites exhibit good electrical conductivity and considerable increases in the interlaminar shear strength, relative to fiber composites without integrated CNTs. Mechanical, chemical and morphological characterization of the coated fiber surfaces reveal interface/interphase modification resulting from the coating is responsible for the improved mechanical and electrical properties. The CNT-coated glass-fiber laminates also exhibited clear changes in electrical resistance as a function of applied shear strain and enables self-sensing of the transition between elastic and plastic load regions. PMID:23379418

  4. Environmental effects on the hybrid glass fiber/carbon fiber composites

    NASA Astrophysics Data System (ADS)

    Tsai, Yun-I.

    2009-12-01

    Fiber reinforced polymer composites (FRPCs) have been widely used to replace conventional metals due to the high specific strength, fatigue resistance, and light weight. In the power distribution industry, an advanced composites rod has been developed to replace conventional steel cable as the load-bearing core of overhead conductors. Such conductors, called aluminum conductor composite core (ACCC) significantly increases the transmitting efficiency of existing power grid system without extensive rebuilding expenses, while meeting future demand for electricity. In general, the service life of such overhead conductors is required to be at least 30 years. Therefore, the long-term endurance of the composite core in various environments must be well-understood. Accelerated aging by hygrothermal exposure was conducted to determine the effect of moisture on the glass fiber (GF)/carbon fiber (CF) hybrid composites. The influence of water immersion and humid air exposure on mechanical properties is investigated. Results indicated that immersion in water is the most severe environment for such hybrid GF/CF composites, and results in greater saturation and degradation of properties. When immersed directly in water, the hybrid GF/CF composites exhibit a moisture uptake behavior that is more complex than composite materials reinforced with only one type of fiber. The unusual diffusion behavior is attributed to a higher packing density of fibers at the annular GF/CF interface, which acts as a temporary moisture barrier. Moisture uptake leads to the mechanical and thermal degradation of such hybrid GF/CF composites. Findings presented here indicate that the degradation is a function of exposure temperature, time, and moisture uptake level. Results also indicate that such hybrid GF/CF composites recover short beam shear (SBS) strength and glass transition temperature (Tg) values comparable to pre-aged samples after removal of the absorbed moisture. In the hygrothermal environment

  5. Aging characteristics of short glass fiber reinforced ZA-27 alloy composite materials

    NASA Astrophysics Data System (ADS)

    Sharma, S. C.; Girish, B. M.; Satish, B. M.; Kamath, R.

    1998-12-01

    Aging characteristics of short glass fiber reinforced ZA-27 alloy composite materials have been evaluated in the present study. The liquid metallurgy technique was used to fabricate the composites, in which preheated short glass fibers were introduced into the ZA-27 alloy melt above its liquidus temperature. The aging temperature employed was 125 °C for 6, 12,18, and 24 h. The aged alloy (no fibers) reached the peak hardness after 18 h, while the composites (regardless of filler content) reached the same hardness in 12 h. It is hypothesized that the aging treatment of a composite improves the strength of the interface between the short fibers and the matrix. This is confirmed by the tensile fractograph analysis, which indicates that at a given aging temperature, the composites aged for 18 h exhibit short fibers that remain attached to the metal matrix, while those aged for 6 h undergo debonding.

  6. Single-mode hollow-core photonic crystal fiber made from soft glass.

    PubMed

    Jiang, X; Euser, T G; Abdolvand, A; Babic, F; Tani, F; Joly, N Y; Travers, J C; Russell, P St J

    2011-08-01

    We demonstrate the first soft-glass hollow core photonic crystal fiber. The fiber is made from a high-index lead-silicate glass (Schott SF6, refractive index 1.82 at 500 nm). Fabricated by the stack-and-draw technique, the fiber incorporates a 7-cell hollow core embedded in a highly uniform 6-layer cladding structure that resembles a kagomé-like lattice. Effective single mode guidance of light is observed from 750 to 1050 nm in a large mode area (core diameter ~30 µm) with a low loss of 0.74 dB/m. The underlying guidance mechanism of the fiber is investigated using finite element modeling. The fiber is promising for applications requiring single mode guidance in a large mode area, such as particle guidance, fluid and gas filled devices. PMID:21934907

  7. Tapered TeX glass optical fibers for remote IR spectroscopic analysis

    NASA Astrophysics Data System (ADS)

    Le Foulgoc, Karine; Le Neindre, Lydia; Zhang, Xhang H.; Lucas, Jacques

    1996-12-01

    Infrared TeX fibers operating in a wide wavelength region have various potential uses in the short distance area such as laser power delivery, remote temperature monitoring and chemical analysis. TeX glass fibers with a minimum attenuation of 0.5 dB/m in the 7 - 10 micrometer range have been obtained. A plastic coating protects these fibers from external environment and improves their mechanical properties. Remote spectroscopy using mono-index fiber is one of the most promising applications. This new technology allows the identification and in situ analysis of many substances such as oils and fertilizers, which have their fingerprint in the 2 - 13 micrometer domain. The detection efficiency using evanescent wave absorption has been studied as a function of the fiber's diameter. It is found that the sensitivity increases very rapidly when the fibers' diameter decreases. The possibility of detecting very low concentrations has been tested by using TeX tapered fibers.

  8. Fabrication of porous ceramic via recycling of glass with paper fiber as sacrificial fugitive

    NASA Astrophysics Data System (ADS)

    Badarulzaman, N. A.; Hamidon, A.; Nor, M. A. A. M.

    2015-05-01

    Recycled glass powder was added with ball clay and feldspar using ratio 90:5:5. The blend were mixed into different amount of paper fiber and cast into porous ceramic. Samples prepared with different compositions (2, 4, 6, 8, and 10 wt % of paper fiber) were heat treated at constant temperature (750 °C) for an hour. Samples with high percentage of paper fiber gave the largest pore size in the ceramic body, meanwhile lower percentage of paper fiber produced ceramic body with smaller pore size.

  9. Preparation, mechanical, and in vitro properties of glass fiber-reinforced polycarbonate composites for orthodontic application.

    PubMed

    Tanimoto, Yasuhiro; Inami, Toshihiro; Yamaguchi, Masaru; Nishiyama, Norihiro; Kasai, Kazutaka

    2015-05-01

    Generally, orthodontic treatment uses metallic wires made from stainless steel, cobalt-chromium-nickel alloy, β-titanium alloy, and nickel-titanium (Ni-Ti) alloy. However, these wires are not esthetically pleasing and may induce allergic or toxic reactions. To correct these issues, in the present study we developed glass-fiber-reinforced plastic (GFRP) orthodontic wires made from polycarbonate and E-glass fiber by using pultrusion. After fabricating these GFRP round wires with a diameter of 0.45 mm (0.018 inch), we examined their mechanical and in vitro properties. To investigate how the glass-fiber diameter affected their physical properties, we prepared GFRP wires of varying diameters (7 and 13 µm). Both the GFRP with 13-µm fibers (GFRP-13) and GFRP with 7 µm fibers (GFRP-7) were more transparent than the metallic orthodontic wires. Flexural strengths of GFRP-13 and GFRP-7 were 690.3 ± 99.2 and 938.1 ± 95.0 MPa, respectively; flexural moduli of GFRP-13 and GFRP-7 were 25.4 ± 4.9 and 34.7 ± 7.7 GPa, respectively. These flexural properties of the GFRP wires were nearly equivalent to those of available Ni-Ti wires. GFRP-7 had better flexural properties than GFRP-13, indicating that the flexural properties of GFRP increase with decreasing fiber diameter. Using thermocycling, we found no significant change in the flexural properties of the GFRPs after 600 or 1,200 cycles. Using a cytotoxicity detection kit, we found that the glass fiber and polycarbonate components comprising the GFRP were not cytotoxic within the limitations of this study. We expect this metal-free GFRP wire composed of polycarbonate and glass fiber to be useful as an esthetically pleasing alternative to current metallic orthodontic wire. PMID:25052046

  10. Ply Thickness Fiber Glass on Windmill Drive Salt Water Pump

    NASA Astrophysics Data System (ADS)

    Sifa, Agus; Badruzzaman; Suwandi, Dedi

    2016-04-01

    Factors management of salt-making processes need to be considered selection of the location and the season is very important to support the efforts of salting. Windmills owned by the farmers are still using wood materials are made each year it is not effectively done and the shape of windmills made not in accordance with the requirements without considering the wind speed and the pumping speed control influenced by the weight and size of windmill, it affects the productivity of salt. to optimize the function of windmills on pumping salt water by change the material blade on the wheel by using a material composite, composite or fiberglass are used for blades on windmills made of a material a mixture of Epoxy-Resin and Matrix E-Glass. The mechanical characteristics of the power of his blade one of determining the materials used and the thickness of the blade, which needed a strong and lightweight. The calculation result thick fiberglass with a composition of 60% fiber and 40% epoxy, at a wind speedof area salt fields 9 m/s, the drag force that occurs at 11,56 kg, then the calculation result by 0,19 mm thick with a layer of 10, the total thickness of 1,9 mm, with a density of 1760 kg/m3, mechanical character of elongated elastic modulus of 46200 MPa, modulus of transverse elasticity of 10309,6 MPa, shear modulus of 3719 MPa and Poisson ratio of 0,31, then the calculation using the finite element ABAQUS obtained critical point at the confluence of the blade to the value of Von Mises tension was happening 1,158e9 MPa maximum and minimum 2,123e5 MPa, for a maximum value of displacement occurred condition at the tip of the blade. The performance test results windmills at a wind speed of 5,5 m/s wind power shows that occur 402,42 watts and power turbines produced 44,21 watt, and TSR 0,095 and the value Cp of 0,1, test results windmill in salt fields in the beginning rotation windmill lighter, able to move above wind speed of 5.5 m/s.

  11. Strongly Nonlinear Optical Glass Fibers from Noncentrosymmetric Phase-Change Chalcogenide Materials

    SciTech Connect

    Chung, In; Jang, Joon I.; Malliakas, Christos D.; Ketterson, John B.; Kanatzidis, Mercouri G.

    2010-08-27

    We report that the one-dimensional polar selenophosphate compounds APSe{sub 6} (A = K, Rb), which show crystal-glass phase-change behavior, exhibit strong second harmonic generation (SHG) response in both crystal and glassy forms. The crystalline materials are type-I phase-matchable with SHG coefficients {chi}{sup (2)} of 151.3 and 149.4 pm V{sup -1} for K{sup +} and Rb{sup +} salts, respectively, which is the highest among phase-matchable nonlinear optical (NLO) materials with band gaps over 1.0 eV. The glass of APSe{sub 6} exhibits comparable SHG intensities to the top infrared NLO material AgGaSe{sub 2} without any poling treatments. APSe{sub 6} exhibit excellent mid-IR transparency. We demonstrate that starting from noncentrosymmetric phase-change materials such as APSe{sub 6} (A = K, Rb), we can obtain optical glass fibers with strong, intrinsic, and temporally stable second-order nonlinear optical (NLO) response. The as-prepared glass fibers exhibit SHG and difference frequency generation (DFG) responses over a wide range of wavelengths. Raman spectroscopy and pair distribution function (PDF) analyses provide further understanding of the local structure in amorphous state of KPSe{sub 6} bulk glass and glass fiber. We propose that this approach can be widely applied to prepare permanent NLO glass from materials that undergo a phase-change process.

  12. Fiber-matrix integrity, micromorphology and flexural strength of glass fiber posts: Evaluation of the impact of rotary instruments.

    PubMed

    Pereira, Gabriel Kalil Rocha; Lançanova, Mateus; Wandscher, Vinicius Felipe; Kaizer, Osvaldo Bazzan; Limberger, Inácio; Özcan, Mutlu; Valandro, Luiz Felipe

    2015-08-01

    Several rotary instruments have been daily employed on clinic to promote cut aiming to adjust the length of fiber posts to the radicular conduct, but there is no information on the literature about the effects of the different rotary instruments and its impact on the micromorphology of surface and mechanical properties of the glass fiber post. This study aimed the impact of rotary instruments upon fiber-matrix integrity, micromorphology and flexural-strength of glass-fiber posts (GFP). GFP (N=110) were divided into 5 groups: Ctrl: as-received posts, DBc: coarse diamond-bur, DBff: extra-fine diamond-bur, CB: carbide-bur, DD: diamond-disc. Cutting procedures were performed under abundant irrigation. Posts exposed to rotary instruments were then subjected to 2-point inclined loading test (compression 45°) (n=10/group) and 3-point flexural-strength test (n=10/group). Fiber-matrix integrity and micromorphology at the cut surface were analyzed using a SEM (n=2/group). Cutting procedures did not significantly affect the 2-point (51.7±4.3-56.7±5.1 MPa) (p=0.0233) and 3-point flexural-strength (671.5±35.3-709.1±33.1 MPa) (p=0.0968) of the posts (One-way ANOVA and Tukey׳s test). Fiber detachment was observed only at the end point of the cut at the margins of the post. Cut surfaces of the CB group were smoother than those of the other groups. After 3-point flexural strength test, fiber-matrix separation was evident at the tensile side of the post. Rotary instruments tested with simultaneous water-cooling did not affect the resistance of the tested fiber posts but caused disintegration of the fibers from the matrix at the end of the cut, located at the margins. PMID:25955561

  13. Facile synthesis 3D flexible core-shell graphene/glass fiber via chemical vapor deposition

    NASA Astrophysics Data System (ADS)

    Yang, Cheng; Xu, Yuanyuan; Zhang, Chao; Sun, Zhencui; Chen, Chuansong; Li, Xiuhua; Jiang, Shouzhen; Man, Baoyuan

    2014-08-01

    Direct deposition of graphene layers on the flexible glass fiber surface to form the three-dimensional (3D) core-shell structures is offered using a two-heating reactor chemical vapor deposition system. The two-heating reactor is utilized to offer sufficient, well-proportioned floating C atoms and provide a facile way for low-temperature deposition. Graphene layers, which are controlled by changing the growth time, can be grown on the surface of wire-type glass fiber with the diameter from 30 nm to 120 um. The core-shell graphene/glass fiber deposition mechanism is proposed, suggesting that the 3D graphene films can be deposited on any proper wire-type substrates. These results open a facile way for direct and high-efficiency deposition of the transfer-free graphene layers on the low-temperature dielectric wire-type substrates.

  14. On the study of crack-initiation fracture toughness of fiber glass asphalt shingles

    SciTech Connect

    Shiao, M.L.

    1999-07-01

    The fracture behavior of fiber glass asphalt shingles was examined by measuring their J-integral fracture toughness at crack initiation. The corresponding fracture mechanisms were also studied by in situ fracture observation and by scanning electron microscopy. The applicability of using J-integral fracture toughness to characterize asphalt shingles was discussed and its relationships to other mechanical properties was established. The results indicated that the fracture toughness at crack initiation can be accurately measured for fiber glass shingles and the values may be used to characterize their cracking resistance. Fracture toughness measured from various shingle samples was found to correlate to the shingle's tensile toughness and to its tear strength. Preliminary results on fracture mechanisms suggested that failure in the asphalt coatings by micro-cavitation may be the controlling event leading to crack advance. The importance of the glass fiber mat on a shingle's resistance to fracture was also discussed.

  15. Mid-infrared surface plasmon polariton chemical sensing on fiber-coupled ITO coated glass

    NASA Astrophysics Data System (ADS)

    Martínez, Javier; Ródenas, Airán; Aguiló, Magdalena; Fernandez, Toney; Solis, Javier; Díaz, Francesc

    2016-06-01

    A novel fiber-coupled ITO coated glass slide sensor for performing surface plasmon polariton chemical monitoring in the 3.5 um mid-IR range is reported. Efficient mid-IR fiber coupling is achieved with 3D laser written waveguides, and the coupling of glass waveguide modes to ITO SPPs is driven by the varying phase matching conditions of different aqueous analytes across the anomalous dispersion range determined by their molecular fingerprints. By means of using both a mid-IR fiber supercontinuum source and a diode laser the excitation of SPPs is demonstrated. The efficient optical monitoring of mid-IR SPPs in smart glass could have a broad range of applications in biological and chemical sensing.

  16. Analysis of the mechanical and thermal properties of jute and glass fiber as reinforcement epoxy hybrid composites.

    PubMed

    Braga, R A; Magalhaes, P A A

    2015-11-01

    This work describes the study to investigate and compare the mechanical and thermal properties of raw jute and glass fiber reinforced epoxy hybrid composites. To improve the mechanical properties, jute fiber was hybridized with glass fiber. Epoxy resin, jute and glass fibers were laminated in three weight ratios (69/31/0, 68/25/7 and 64/18/19) respectively to form composites. The tensile, flexural, impact, density, thermal and water absorption tests were carried out using hybrid composite samples. This study shows that the addition of jute fiber and glass fiber in epoxy, increases the density, the impact energy, the tensile strength and the flexural strength, but decreases the loss mass in function of temperature and the water absorption. Morphological analysis was carried out to observe fracture behavior and fiber pull-out of the samples using scanning electron microscope. PMID:26249589

  17. Push-out bond strength of fiber posts to root dentin using glass ionomer and resin modified glass ionomer cements

    PubMed Central

    PEREIRA, Jefferson Ricardo; da ROSA, Ricardo Abreu; SÓ, Marcus Vinícius Reis; AFONSO, Daniele; KUGA, Milton Carlos; HONÓRIO, Heitor Marques; do VALLE, Accácio Lins; VIDOTTI, Hugo Alberto

    2014-01-01

    Objective The purpose of this study was to assess the push-out bond strength of glass fiber posts to root dentin after cementation with glass ionomer (GICs) and resin-modified glass ionomer cements (RMGICs). Material and Methods Fifty human maxillary canines were transversally sectioned at 15 mm from the apex. Canals were prepared with a step back technique until the application of a #55 K-file and filled. Post spaces were prepared and specimens were divided into five groups according to the cement used for post cementation: Luting & Lining Cement; Fuji II LC Improved; RelyX Luting; Ketac Cem; and Ionoseal. After cementation of the glass fiber posts, all roots were stored at 100% humidity until testing. For push-out test, 1-mm thick slices were produced. The push-out test was performed in a universal testing machine at a crosshead speed of 0.5 mm/minute and the values (MPa) were analyzed by Kolmogorov-Smirnov and Levene's tests and by two-way ANOVA and Tukey's post hoc test at a significance level of 5%. Results Fiber posts cemented using Luting & Lining Cement, Fuji II LC Improved, and Ketac Cem presented the highest bond strength to root dentin, followed by RelyX Luting. Ionoseal presented the lowest bond strength values (P>0.05). The post level did not influence the bond strength of fiber posts to root dentin (P=0.148). The major cause of failure was cohesive at the cement for all GICs and RMGICs. Conclusions Except for Ionoseal, all cements provided satisfactory bond strength values. PMID:25004052

  18. Two-color mid-infrared thermometer with a hollow glass optical fiber

    SciTech Connect

    Small, W. IV; Celliers, P.M.; Da Silva, L.B.; Matthews, D.L.; Soltz, B.A.

    1998-10-01

    We have developed a low-temperature optical-fiber-based two-color infrared thermometer. A single 700-{mu}m-bore hollow glass optical fiber collects and transmits radiation that is then modulated and split into two paths by a reflective optical chopper. Two different thermoelectrically cooled mid-infrared HgCdZnTe photoconductors monitor the chopped signals that are recovered with lock-in amplification. With the two previously obtained blackbody calibration equations, a computer algorithm calculates the true temperature and emissivity of a target in real time, taking into account reflection of the ambient radiation field from the target surface. The small numerical aperture of the hollow glass fiber and the fast response of the detectors, together with the two-color principle, permit high spatial and temporal resolution while allowing the user to dynamically alter the fiber-to-target distance. {copyright} 1998 Optical Society of America

  19. Assessment of Japanese technology in advanced glass and ceramic fibers. Final report

    SciTech Connect

    Messier, D.R.

    1992-06-01

    Summarized herein are the findings from a two month trip to Japan from mid-September to mid-November 1991 to evaluate Japanese technology in oxynitride glasses and fibers and in carbide and nitride fibers and whiskers. The information discussed was obtained through visits to universities, companies, Government institutes, and through attendance at three conferences. It was learned that the development of a process for the production of oxynitride glass fibers is still being actively pursued and that, while high temperature instability problems are well-recognized, the production of carbide or nitride fibers with good high temperature stability is still several years away. Also discussed are new developments in several research areas including ceramic matrix composites, sol-gel technology, ceramic powder preparation, and high strength ceramics.

  20. Silver iodide phosphate glass microsphere resonator integrated on an optical fiber taper.

    PubMed

    Milenko, Karolina; Konidakis, Ioannis; Pissadakis, Stavros

    2016-05-15

    In this Letter, we demonstrate the fabrication and characterization of a robust and functional whispering gallery mode (WGM) resonating system based on a silver iodide phosphate glass microsphere melted on an optical fiber taper. The fabrication process is presented, together with spectral characterization of the device. The effect of the thermal annealing of the soft glass resonator on the whispering gallery modes' excitation and Q-factor is shown and discussed. PMID:27176958

  1. Structural considerations in design of lightweight glass-fiber composite pressure vessels

    NASA Technical Reports Server (NTRS)

    Faddoul, J. R.

    1973-01-01

    The development of structurally efficient, metal-lined, glass-fiber composite pressure vessels. Both the current state-of-the-art and current problems are discussed along with fracture mechanics considerations for the metal liner. The design concepts used for metal-lined, glass-fiber, composite pressure vessels are described and the structural characteristics of the composite designs are compared with each other and with homogeneous metal pressure vessels. Specific design techniques and available design data are identified. Results of a current program to evaluate flaw growth and fracture characteristics of the metal liners are reviewed and the impact of these results on composite pressure vessel designs is discussed.

  2. Method of producing a silicon carbide fiber reinforced strontium aluminosilicate glass-ceramic matrix composite

    NASA Technical Reports Server (NTRS)

    Bansal, Narottam P. (Inventor)

    1995-01-01

    A SrO-Al2O3-2SrO2 (SAS) glass ceramic matrix is reinforced with CVD SiC continuous fibers. This material is prepared by casting a slurry of SAS glass powder into tapes. Mats of continuous CVD-SiC fibers are alternately stacked with the matrix tapes. This tape-mat stack is warm-pressed to produce a 'green' composite. Organic constituents are burned out of the 'green' composite, and the remaining interim material is hot pressed.

  3. Silicon carbide fiber reinforced strontium aluminosilicate glass-ceramic matrix composite

    NASA Technical Reports Server (NTRS)

    Bansal, Narottam (Inventor)

    1992-01-01

    A SrO-Al2O3 - 2SrO2 (SAS) glass ceramic matrix is reinforced with CVD SiC continuous fibers. This material is prepared by casting a slurry of SAS glass powder into tapes. Mats of continuous CVD-SiC fibers are alternately stacked with the matrix tapes. This tape-mat stack is warm-pressed to produce a 'green' composite. Organic constituents are burned out of the 'green' composite, and the remaining interim material is hot pressed.

  4. Structural considerations in design of lightweight glass-fiber composite pressure vessels

    NASA Technical Reports Server (NTRS)

    Faddoul, J. R.

    1973-01-01

    The design concepts used for metal-lined glass-fiber composite pressure vessels are described, comparing the structural characteristics of the composite designs with each other and with homogeneous metal pressure vessels. Specific design techniques and available design data are identified. The discussion centers around two distinctly different design concepts, which provide the basis for defining metal lined composite vessels as either (1) thin-metal lined, or (2) glass fiber reinforced (GFR). Both concepts are described and associated development problems are identified and discussed. Relevant fabrication and testing experience from a series of NASA-Lewis Research Center development efforts is presented.

  5. Chalcogenide glass fibers: Optical window tailoring and suitability for bio-chemical sensing

    NASA Astrophysics Data System (ADS)

    Lucas, Pierre; Coleman, Garrett J.; Jiang, Shibin; Luo, Tao; Yang, Zhiyong

    2015-09-01

    Glassy materials based on chalcogen elements are becoming increasingly prominent in the development of advanced infrared sensors. In particular, infrared fibers constitute a desirable sensing platform due to their high sensitivity and versatile remote collection capabilities for in-situ detection. Tailoring the transparency window of an optical material to the vibrational signature of a target molecule is important for the design of infrared sensor, and particularly for fiber evanescent wave spectroscopy. Here we review the basic principles and recent developments in the fabrication of chalcogenide glass infrared fibers for application as bio-chemical sensors. We emphasize the challenges in designing materials that combine good rheological properties with chemical stability and sufficiently wide optical windows for bio-chemical sensing. The limitation in optical transparency due to higher order overtones of the amorphous network vibrations is established for this family of glasses. It is shown that glasses with wide optical window suffer from higher order overtone absorptions. Compositional engineering with heavy elements such as iodine is shown to widen the optical window but at the cost of lower chemical stability. The optical attenuations of various families of chalcogenide glass fibers are presented and weighed for their applications as chemical sensors. It is then shown that long-wave infrared fibers can be designed to optimize the collection of selective signal from bio-molecules such as cells and tissues. Issues of toxicity and mechanical resistance in the context of bio-sensing are also discussed.

  6. Remote infrared chemical sensing using highly durable AlF(3)-based glass fibers.

    PubMed

    Iqbal, T; Shahriari, M R; Ulbrich, R; Sigel, G H

    1991-10-15

    Unclad, low-loss AlF(3)-based glass fibers with enhanced chemical durability have been successfully used for the first time to our knowledge as intrinsic evanescent infrared sensors for monitoring liquid chemicals. Different liquids with absorption bands between 1 and 4.5 microm, such as alcohol, acetonitrile, and mixtures of alcohol/acetonitrile and water/acetonitrile, have been tested. These fibers have also been used successfully as distributed sensors for simultaneous monitoring of different chemical species. PMID:19777048

  7. Halo-tellurite glass fiber with low OH content for 2-5µm mid-infrared nonlinear applications.

    PubMed

    Feng, Xian; Shi, Jindan; Segura, Martha; White, Nicolas M; Kannan, Pradeesh; Loh, Wei H; Calvez, Laurent; Zhang, Xianghua; Brilland, Laurent

    2013-08-12

    We report the fabrication of new dehydrated halo-tellurite glass fibers with low OH content (1ppm in weight) and low OH-induced attenuation of 10dB/m in 3-4 µm region. It shows halo-tellurite glass fibers a promising candidate for nonlinear applications in 2-5µm region. PMID:23938808

  8. Breaking the glass ceiling: hollow OmniGuide fibers

    NASA Astrophysics Data System (ADS)

    Johnson, Steven G.; Ibanescu, Mihai; Skorobogatiy, Maksim A.; Weisberg, Ori; Engeness, Torkel D.; Soljacic, Marin; Jacobs, Steven A.; Joannopoulos, John D.; Fink, Yoel

    2002-04-01

    We argue that OmniGuide fibers, which guide light within a hollow core by concentric multilayer films having the property of omnidirectional reflection, have the potential to lift several physical limitations of silica fibers. We show how the strong confinement in OmniGuide fibers greatly suppresses the properties of the cladding materials: even if highly lossy and nonlinear materials are employed, both the intrinsic losses and nonlinearities of silica fibers can be surpassed by orders of magnitude. This feat, impossible to duplicate in an index-guided fiber with existing materials, would open up new regimes for long-distance propagation and dense wavelength-division multiplexing (DWDM). The OmniGuide-fiber modes bear a strong analogy to those of hollow metallic waveguides; from this analogy, we are able to derive several general scaling laws with core radius. Moreover, there is strong loss discrimination between guided modes, depending upon their degree of confinement in the hollow core: this allows large, ostensibly multi-mode cores to be used, with the lowest-loss TE01 mode propagating in an effectively single-mode fashion. Finally, because this TE01 mode is a cylindrically symmetrical ('azimuthally' polarized) singlet state, it is immune to polarization-mode dispersion (PMD), unlike the doubly-degenerate linearly-polarized modes in silica fibers that are vulnerable to birefringence.

  9. Water Absorption and Thickness Swelling Behavior of Polypropylene Reinforced with Hybrid Recycled Newspaper and Glass Fiber

    NASA Astrophysics Data System (ADS)

    Shakeri, Alireza; Ghasemian, Ali

    2010-04-01

    This study aims to investigate the moisture absorption of recycled newspaper fiber and recycled newspaper-glass fiber hybrid reinforced polypropylene composites to study their suitability in outdoor applications. In this work composite materials were made from E-glass fiber (G), recycled newspaper (NP) and polypropylene (PP), by using internal mixing and hot-pressing molding. Long-term water absorption (WA) and thickness swelling (TS) kinetics of the composites was investigated with water immersion. It was found that the WA and TS increase with NP content in composite and water immersion time before an equilibrium condition was reached. Composites made from the NP show comparable results as those made of the hybrid fiber. The results suggest that the water absorption and thickness swelling composite decrease with increasing glass fiber contents in hybrid fiber composite. It is interesting to find that the WA and TS can be reduced significantly with incorporation of a coupling agent (maleated polypropylene) in the composite formulation. Further studies were conducted to model the water diffusion and thickness swelling of the composites. Diffusion coefficients and swelling rate parameters in the models were obtained by fitting the model predictions with the experimental data.

  10. Numerical study on mixing performance of glass fiber dispersion in a twin-screw extruder with backward-mixing elements

    NASA Astrophysics Data System (ADS)

    Hirata, Kunihiro; Ishida, Hiroshi; Hiragori, Motohiro; Nakayama, Yasuya; Kajiwara, Toshihisa

    2015-05-01

    In the kneading of glass-fiber-reinforced plastics by twin-screw extrusion, the use of a backward-mixing screw (BMS) element for melt mixing has been found to be effective in dispersing glass-fiber bundles. In this study, we use the computational fluid dynamics (CFD) to study the mechanism of dispersion by a BMS element for glass fiber bundles. The result of CFD for a BMS and a forward kneading disk (FKD) reveals that the melt mixing by a BMS is highly effective to act the required stress on overall resin. In addition, there is a good correlation between the incidence of undispersed glass-fiber bundles measured experimentally and the minimum value of distribution of the time-integrated stress calculated numerically. On the basis of the above results, we propose a method to predict the operating conditions in which the incident probability of undispersed glass-fiber bundles and thermal degradation are controlled.

  11. High-efficiency ytterbium-free erbium-doped all-glass double cladding silicate glass fiber for resonantly-pumped fiber lasers.

    PubMed

    Qiang, Zexuan; Geng, Jihong; Luo, Tao; Zhang, Jun; Jiang, Shibin

    2014-02-01

    A highly efficient ytterbium-free erbium-doped silicate glass fiber has been developed for high-power fiber laser applications at an eye-safe wavelength near 1.55 μm. Our preliminary experiments show that high laser efficiency can be obtained from a relatively short length of the gain fiber when resonantly pumped at 1535 nm in both core- and cladding-pumping configurations. With a core-pumping configuration as high as 75%, optical-to-optical efficiency and 4 W output power were obtained at 1560 nm from a 1 m long gain fiber. When using a cladding-pumping configuration, approximately 13 W output power with 67.7% slope efficiency was demonstrated from a piece of 2 m long fiber. The lengths of silicate-based gain fiber are much shorter than their silica-based counterparts used in other experiments, which is significantly important for high-power narrow-band and/or pulsed laser applications. PMID:24514181

  12. The deposition of boron nitride and carbon films on silica glass fibers

    SciTech Connect

    Smith, W.L.; Michalske, T.A.; Rye, R.R.

    1993-11-01

    A chemical vapor deposition technique is used to produce amorphous boron nitride and carbon thin films on high strength silica glass fibers. In this method, the fiber is drawn under ultra high vacuum conditions and low pressure process gases, in the presence of a hot tungsten filament, are used to grow films at low substrate temperatures. Films deposited with this technique do not degrade the intrinsic pristine strength of the silica fibers under dry conditions and, when stressed in chemically aggressive environments, act as effective barrier coatings.

  13. Non-contact vibration sensor using bifurcated bundle glass fiber for real-time monitoring

    NASA Astrophysics Data System (ADS)

    Putha, K.; Dinakar, D.; Shankar, M. Sai; Srimannarayana, K.; Vengal Rao, P.; Sengupta, D.; Reddy, P. Saidi

    2011-12-01

    A fiber optic vibration sensor is demonstrated using bifurcated bundle fiber based on the principle of extrinsic displacement sensor. An IR source is used along with glass fibers to avoid the effect of stray light in sensing. The encapsulation of the sensor enables easy alignment, flexible handling and usage in harsh environments. The sensor is capable of measuring the frequencies up to 650Hz with vibration amplitude resolution of 10μm, enough to monitor the vibrations generated in heavy machines. The sensor is tested in the field to monitor the health condition of the diesel engine.

  14. Chronic inhalation study of fiber glass and amosite asbestos in hamsters: twelve-month preliminary results.

    PubMed Central

    Hesterberg, T W; Axten, C; McConnell, E E; Oberdörster, G; Everitt, J; Miiller, W C; Chevalier, J; Chase, G R; Thevenaz, P

    1997-01-01

    The effects of chronic inhalation of glass fibers and amosite asbestos are currently under study in hamsters. The study includes 18 months of inhalation exposure followed by lifetime recovery. Syrian golden hamsters are exposed, nose only, for 6 hr/day, 5 day/week to size-selected test fibers: MMVF10a (Schuller 901 insulation glass); MMVF33 (Schuller 475 durable glass); amosite asbestos (three doses); or to filtered air (controls). Here we report interim results on airborne fiber characterization, lung fiber burden, and pathology (preliminary) through 12 months. Aerosolized test fibers averaged 15 to 20 microns in length and 0.5 to 1 micron in diameter. Target aerosol concentrations of World Health Organization (WHO) fibers (longer than 5 microns) were 250 fibers/cc for MMVF10a and MMVF33, and 25, 125, or 250 fibers/cc for amosite. WHO fiber lung burdens showed time-dependent and (for amosite) dose-dependent increases. After a 12-month exposure, lung burdens of fibers longer than 20 microns were greatest with amosite high and mid doses, similar for low-dose amosite and MMVF33, and smaller for MMVF10a. Biological responses of animals exposed for 12 months to MMVF10a were limited to nonspecific pulmonary inflammation. However, exposures to MMVF33 and each of three doses of amosite were associated with lung fibrosis and possible mesotheliomas (1 with MMVF33 and 2, 3, and 1 with amosite low, mid, and high doses, respectively). Pulmonary and pleural changes associated with amosite were qualitatively and quantitatively more severe than those associated with MMVF33. As of the 12-month time point, this study demonstrates that two different fiber glass compositions with similar fiber dimensions but different durabilities can have distinctly different effects on the hamster lung and pleura after inhalation exposure. (Preliminary tumor data through 18 months of exposure and 6 weeks of postexposure recovery became available as this manuscript went to press: No tumors were

  15. Effect of fabric structure and polymer matrix on flexural strength, interlaminar shear stress, and energy dissipation of glass fiber-reinforced polymer composites

    Technology Transfer Automated Retrieval System (TEKTRAN)

    We report the effect of glass fiber structure and the epoxy polymer system on the flexural strength, interlaminar shear stress (ILSS), and energy absorption properties of glass fiber-reinforced polymer (GFRP) composites. Four different GFRP composites were fabricated from two glass fiber textiles of...

  16. Mechanical Properties of PP/Jute and Glass Fibers Composites: The Statistical Investigation

    NASA Astrophysics Data System (ADS)

    Esfandiari, Amirhossein

    A systematic and statistical approach to evaluate and predict the properties of random discontinuous natural fiber reinforced composites was studied. Different composites based on polypropylene and reinforced with natural fibers (flax and glass) have been made and their mechanical properties are measured together with the distribution of the fiber size and the fiber diameter. The values obtained were related to the theoretical predictions, using a combination of the Griffith theory for the effective properties of the natural fibers and the Halpin-Tsai equation for the elastic modulus of the composites. The relationships between experimental results and theoretical predictions are statistically analyzed using a probability density function estimation approach based on neural networks. The results show a more accurate expected value with respect to the traditional statistical function estimation approach.

  17. Development of potassium ion conducting hollow glass fibers. [potassium sulfur battery

    NASA Technical Reports Server (NTRS)

    Tsang, F. Y.

    1974-01-01

    Potassium ion conducting glasses, chemically resistant to potassium, potassium sulfide and sulfur, were made and their possible utility as the membrane material for a potassium/sulfur battery was evaluated. At least one satisfactory candidate was found. It possesses an electrical resistance which makes it usable as a membrane in the form of a fine hollow fiber. It's chemical and electrochemical resistances are excellent. The other aspects of the possible potassium sulfur battery utilizing such fine hollow fibers, including the header (or tube sheet) and a cathode current collector were studied. Several cathode materials were found to be satisfactory. None of the tube sheet materials studied possessed all the desired properties. Multi-fiber cells had very limited life-time due to physical failure of fibers at the fiber/tube sheet junctions.

  18. Synchronous Cultures of Bacillus subtilis Obtained by Filtration with Glass Fiber Filters

    PubMed Central

    Sargent, Michael G.

    1973-01-01

    A simple method of potentially wide applicability for obtaining synchronous cultures of Bacillus subtilis based on size selection is described. Using glass fiber filters, a population (about 1 to 2% of the parent population) can be obtained substantially enriched for small cells which grow synchronously. A method for rapidly concentrating dilute suspensions of cells is described. PMID:4200855

  19. Influence of laser radiation on induced absorption spectra of pure quartz glass optical fibers

    NASA Astrophysics Data System (ADS)

    Dianov, Y. M.; Karpechev, V. N.; Korniyenko, L. S.; Rybaltovskiy, A. O.; Chernov, P. V.

    1986-01-01

    The influence of laser radiation on radiation color centers and their associated induced absorption in the spectra of irradiated glass optical fibers is investigated. The glass fiber specimens employed had 40 to 50 micron diameter cores made of day pure quartz glass. The optical fibers were 6 to 20 meters long, produced by chemical precipitation from the gaseous phase and clad with reflecting borosilicate glass. Spectral measurements of the induced absorption in the ultraviolet region were made using an FEU-71 photodetector and a sounding radiation source. The stimulated laser emission power in the cross section of the optical fiber was measured by a photodiode; the absorption spectra were recorded by the fragment method. Eight different types of color centers were isolated whose bands cover practically the entire observed absorption spectra. The connection found between color centers and a 340 nm absorption band, and color center with absorption in the infrared band, indicate that absorption in the ultraviolet band can have a significant influence on the amount of induced absorption in the infrared band.

  20. Effects of particle size and velocity on burial depth of airborne particles in glass fiber filters

    SciTech Connect

    Higby, D.P.

    1984-11-01

    Air sampling for particulate radioactive material involves collecting airborne particles on a filter and then determining the amount of radioactivity collected per unit volume of air drawn through the filter. The amount of radioactivity collected is frequently determined by directly measuring the radiation emitted from the particles collected on the filter. Counting losses caused by the particle becoming buried in the filter matrix may cause concentrations of airborne particulate radioactive materials to be underestimated by as much as 50%. Furthermore, the dose calculation for inhaled radionuclides will also be affected. The present study was designed to evaluate the extent to which particle size and sampling velocity influence burial depth in glass-fiber filters. Aerosols of high-fired /sup 239/PuO/sub 2/ were collected at various sampling velocities on glass-fiber filters. The fraction of alpha counts lost due to burial was determined as the ratio of activity detected by direct alpha count to the quantity determined by photon spectrometry. The results show that burial of airborne particles collected on glass-fiber filters appears to be a weak function of sampling velocity and particle size. Counting losses ranged from 0 to 25%. A correction that assumes losses of 10 to 15% would ensure that the concentration of airborne alpha-emitting radionuclides would not be underestimated when glass-fiber filters are used. 32 references, 21 figures, 11 tables.

  1. MUTAGENICITY OF TEFLON-COATED GLASS FIBER FILTERS: A POTENTIAL PROBLEM AND SOLUTIONS

    EPA Science Inventory

    Teflon-coated glass fiber filters, used in studies of airborne particulate matter, were tested for mutagenic activity using the Salmonella/mammalian-microsome (Ames) assay. For each sample, eight blank filters were simultaneously extracted with dichloromethane (DCM), and the extr...

  2. Effects of boron and glass hybrid epoxy-composites on graphite-fiber release in an aircraft fire

    NASA Technical Reports Server (NTRS)

    Tompkins, S. S.; Brewer, W. D.

    1979-01-01

    Recent studies have shown that the benefits gained by using graphite-epoxy composite structures may not be realized without some risk. The graphite fibers are very good electrical conductors and fibers released into the environment during a fire create a possible hazard to electrical equipment. Several graphite-epoxy hybrids were exposed to a fire and simulated explosion and their graphite fiber retention characteristics were examined. Several low melting-temperature glasses which wet and clump graphite-fibers and a glass/graphite fabric which reduced impact damage were identified as promising hybridizing components to minimize graphite fiber release.

  3. Glass Solder Approach for Robust, Low-Loss, Fiber-to-Waveguide Coupling

    NASA Technical Reports Server (NTRS)

    McNeil, Shirley; Battle, Philip; Hawthorne, Todd; Lower, John; Wiley, Robert; Clark, Brett

    2012-01-01

    The key advantages of this approach include the fact that the index of interface glass (such as Pb glass n = 1.66) greatly reduces Fresnel losses at the fiber-to-waveguide interface, resulting in lower optical losses. A contiguous structure cannot be misaligned and readily lends itself for use on aircraft or space operation. The epoxy-free, fiber-to-waveguide interface provides an optically pure, sealed interface for low-loss, highpower coupling. Proof of concept of this approach has included successful attachment of the low-melting-temperature glass to the x-y plane of the crystal, successful attachment of the low-meltingtemperature glass to the end face of a standard SMF (single-mode fiber), and successful attachment of a wetted lowmelting- temperature glass SMF to the end face of a KTP crystal. There are many photonic components on the market whose performance and robustness could benefit from this coupling approach once fully developed. It can be used in a variety of fibercoupled waveguide-based components, such as frequency conversion modules, and amplitude and phase modulators. A robust, epoxy-free, contiguous optical interface lends itself to components that require low-loss, high-optical-power handling capability, and good performance in adverse environments such as flight or space operation.

  4. Optical fibers from sol-gel-derived germania-silica glasses

    NASA Astrophysics Data System (ADS)

    Kirkbir, Fikret; Chaudhuri, S. R.

    1992-12-01

    Step index multimode optical fibers were successfully drawn from germania doped silica rods prepared by sol-gel process. The fiber, drawn using rod-in-tube technique, had a 100 micron core with a pure silica cladding of 140 micron. The numerical aperture of the fiber was 0.21. Initial experimental results indicate an attenuation of 20 dB/km at 850 nm wavelength. Precursors used for sol preparation were tetraethyl orthosilicate, Si(OC2H5)4 and tetraethyl orthogermanate, Ge(OC2H5)4. Clear wet gels were routinely produced without any problem of premature precipitation of germanium dioxide even at high dopant concentration levels. The gels were dried by supercritical drying technique. Dry gels were consolidated to clear glass samples routinely at a temperature of 1300 degree(s)C. Fiber was drawn from these rods at a temperature of 1800 degree(s)C. The sintering parameters, i.e., type of gas flow at different steps of the sintering operation, duration of such steps and temperature were optimized to eliminate reboil of the glass above 1800 degree(s)C, resulting in bubble-free glass fibers.

  5. Properties of glass/carbon fiber reinforced epoxy hybrid polymer composites

    NASA Astrophysics Data System (ADS)

    Patel, R. H.; Sevkani, V. R.; Patel, B. R.; Patel, V. B.

    2016-05-01

    Composite Materials are well known for their tailor-made properties. For the fabrication of composites different types of reinforcements are used for different applications. Sometimes for a particular application, one type of reinforcement may not fulfill the requirements. Therefore, more than one type of reinforcements may be used. Thus, the idea of hybrid composites arises. Hybrid composites are made by joining two or more different reinforcements with suitable matrix system. It helps to improve the properties of composite materials. In the present work glass/carbon fiber reinforcement have been used with a matrix triglycidyl ether of tris(m-hydroxy phenyl) phosphate epoxy resin using amine curing agent. Different physical and mechanical properties of the glass, carbon and glass/carbon fiber reinforced polymeric systems have been found out.

  6. Positive paste with lead-coated glass fibers

    NASA Technical Reports Server (NTRS)

    Rippel, Wally E. (Inventor); Edwards, Dean B. (Inventor)

    1989-01-01

    A reliable positive plate for deep cycle lead-acid batteries is provided by dispersing about 2 percent by volume of fine, short, lead-coated reinforcement fibers such as fiberglass in the positive active paste before being applied to the grid of a battery plate and cured. The fibers improve the structural integrity of the plate and also provide electrical paths in a discharged plate. This results in greater utilization of the lead dioxide active material by preventing charged portions of the plate from becoming electrically isolated.

  7. Investigation of carbonized layer on surface of NaAlSi glass fibers

    NASA Astrophysics Data System (ADS)

    Pentjuss, E.; Lusis, A.; Bajars, G.; Gabrusenoks, J.

    2013-12-01

    There are presented and discussed experimental results about carbonate shell on the sodium rich alumosilicate (NaAlSi) glass fibers and carbonization in wet air atmosphere and water uptake kinetic of such fiber fabrics. The analyzes of water uptake kinetic by regression technique, leaching and heating of carbonized glass fabrics helped to separate stages of fast and slow processes between fiber and carbonate shell and air atmosphere. The shell contains mixture of trona and hydrated sodium carbonate. Heating converts both substances to sodium carbonate. The weight uptake after heating encounters two fast exponential processes associated with water absorption on the surface of carbonated shell and its diffusion into volume. The slow process associates with CO2 and H2O absorption from air, hydration and sodium carbonate conversion to trona.

  8. Separation of Water from Ultralow Sulfur Diesel Using Novel Polymer Nanofiber-Coated Glass Fiber Media.

    PubMed

    Rajgarhia, Stuti S; Jana, Sadhan C; Chase, George G

    2016-08-24

    Polymer nanofibers with interpenetrating network (IPN) morphology are used in this work for the development of composite, hydrophobic filter media in conjunction with glass fibers for removal of water droplets from ultralow sulfur diesel (ULSD). The nanofibers are produced from hydrophobic polyvinyl acetate (PVAc) and hydrophilic polyvinylpyrrolidone (PVP) by spinning the polymer solutions using gas jet fiber (GJF) method. The nanofibers coat the individual glass fibers due to polar-polar interactions during the spinning process and render the filter media highly hydrophobic with a water contact angle approaching 150°. The efficiency of the resultant filter media is evaluated in terms of separation of water droplets of average size 20 μm from the suspensions in ULSD. PMID:27486993

  9. Broadband and high-brightness light source: glass-clad Ti:sapphire crystal fiber.

    PubMed

    Wang, Shih-Chang; Yang, Teng-I; Jheng, Dong-Yo; Hsu, Chun-Yang; Yang, Tzu-Te; Ho, Tuan-Shu; Huang, Sheng-Lung

    2015-12-01

    High-brightness near-infrared broadband amplified spontaneous emission (ASE) was generated by glass-clad Ti:sapphire crystal fibers, which were developed using the co-drawing laser-heated pedestal growth method. As much as 29.2 mW of ASE power was generated using 520 nm laser diodes as the excitation source on an a-cut, 18 μm core-diameter Ti:sapphire crystal fiber (CF). The 3 dB bandwidth was 163.8 nm, and the radiance was 53.94  W·mm(-2) sr(-1). The propagation loss of the glass-clad sapphire CF measured using the cutback method was 0.017  cm(-1) at 780 nm. For single-mode applications, more than 100 μW of power was coupled into a SM600 single-mode fiber. PMID:26625059

  10. Processing and damage recovery of intrinsic self-healing glass fiber reinforced composites

    NASA Astrophysics Data System (ADS)

    Sordo, Federica; Michaud, Véronique

    2016-08-01

    Glass fiber reinforced composites with a self-healing, supramolecular hybrid network matrix were produced using a modified vacuum assisted resin infusion moulding process adapted to high temperature processing. The quality and fiber volume fraction (50%) of the obtained materials were assessed through microscopy and matrix burn-off methods. The thermo-mechanical properties were quantified by means of dynamic mechanical analysis, revealing very high damping properties compared to traditional epoxy-based glass fiber reinforced composites. Self-healing properties were assessed by three-point bending tests. A high recovery of the flexural properties, around 72% for the elastic modulus and 65% of the maximum flexural stress, was achieved after a resting period of 24 h at room temperature. Recovery after low velocity impact events was also visually observed. Applications for this intrinsic and autonomic self-healing highly reinforced composite material point towards semi-structural applications where high damping and/or integrity recovery after impact are required.

  11. Low-temperature evaporative glass scoring using a single-mode ytterbium fiber laser

    NASA Astrophysics Data System (ADS)

    Tu, J. F.; Riley, P. E. B.

    2013-06-01

    Glass cutting is increasingly important in industry to cut glass into various sizes for high definition televisions, cell phones, laptops, and tablet computers. A conventional mechanical cutter is usually used to score the glass before a bending force is applied to separate the glass along the scoring mark. This paper presents a laser glass scoring technique aimed at replacing the mechanical cutter to reduce cracks. This scoring technique, denoted as the Low-temperature Evaporative Glass Scoring process (LEGS), is different because laser energy is not directly absorbed by the glass. To achieve the proposed laser scoring, a laser beam is focused through the glass onto a metal substrate. The metal substrate absorbs the laser energy to generate a metal vapor to etch the glass, forming a scoring mark. The feasibility of this glass scoring technique is demonstrated using a continuous-wave fiber laser, at a low power of 60 W, and a 7075-T6 Aluminum alloy plate as the metal substrate. When the laser beam scans across the substrate, the laser energy creates a quasi-static aluminum molten pool, covered by an aluminum vapor at a temperature about 3000 K. At an optimal setting of 51 μm gap distance, 60 W laser power, and 6 mm/s scoring speed, a uniform scoring mark of 37 μm width and 120 μm depth was successfully generated on a piece of soda-lime glass without visible micro-cracks. The paper also discussed the uncertainties and their remedies involved in the LEGS process. To facilitate the process design, a model for predicting the aluminum vapor temperature was developed. This model accounted for the laser focus, reflection, absorption and transmission, laser energy distribution, and the aluminum melting and vaporization processes. Finally, this model was validated by comparing the actual melt depth of the aluminum substrate with the one predicted by the model.

  12. Thermo-tunable hybrid photonic crystal fiber based on solution-processed chalcogenide glass nanolayers

    PubMed Central

    Markos, Christos

    2016-01-01

    The possibility to combine silica photonic crystal fiber (PCF) as low-loss platform with advanced functional materials, offers an enormous range of choices for the development of fiber-based tunable devices. Here, we report a tunable hybrid silica PCF with integrated As2S3 glass nanolayers inside the air-capillaries of the fiber based on a solution-processed glass approach. The deposited high-index layers revealed antiresonant transmission windows from ~500 nm up to ~1300 nm. We experimentally demonstrate for the first time the possibility to thermally-tune the revealed antiresonances by taking advantage the high thermo-optic coefficient of the solution-processed nanolayers. Two different hybrid fiber structures, with core diameter 10 and 5 μm, were developed and characterized using a supercontinuum source. The maximum sensitivity was measured to be as high as 3.6 nm/°C at 1300 nm. The proposed fiber device could potentially constitute an efficient route towards realization of monolithic tunable fiber filters or sensing elements. PMID:27538726

  13. Magnesium coated phosphate glass fibers for unidirectional reinforcement of polycaprolactone composites.

    PubMed

    Liu, Xiaoling; Grant, David M; Palmer, Graham; Parsons, Andrew J; Rudd, Chris D; Ahmed, Ifty

    2015-10-01

    Bioresorbable composites have shown much potential for bone repair applications, as they have the ability to degrade completely over time and their degradation and mechanical properties can be tailored to suit the end application. In this study, phosphate glass fiber (from the system 45% P2 O5-16% CaO-24% MgO-11% Na2 O-4% Fe2 O3 (given in mol%)) were used to reinforce polycaprolactone (PCL) with approximately 20% fiber volume fraction. The glass fiber surfaces were coated with magnesium (Mg) through magnetron sputtering to improve the fiber-matrix interfacial properties. The Mg coating provided a rough fiber surface (roughness (Ra) of about 44nm). Both noncoated and Mg-coated fiber-reinforced composites were assessed. The water uptake and mass loss properties for the composites were assessed in phosphate-buffered saline (PBS) at 37°C for up to 28 days, and ion release profiles were also investigated in both water and PBS media. Inhibition of media influx was observed for the Mg-coated composites. The composite mechanical properties were characterized on the basis of both tensile and flexural tests and their retention in PBS media at 37°C was also investigated. A higher retention of the mechanical properties was observed for the Mg-coated composites over the 28 days degradation period. PMID:25404499

  14. Optical and spectroscopic characterization of Er3+-Yb3+co-doped tellurite glasses and fibers

    NASA Astrophysics Data System (ADS)

    Narro-García, R.; Desirena, H.; Chillcce, E. F.; Barbosa, L. C.; Rodriguez, E.; De la Rosa, E.

    2014-04-01

    Optical and spectroscopic properties of Er3+-Yb3+ co-doped TeO2-WO3-Nb2O5-Na2O-Al2O3 glasses and fibers were investigated. Emission spectra and fluorescence lifetimes of 4I13/2 level of Er3+ion as a function of rare earth concentration and fiber length were measured in glasses. Results show that the self-absorption effect broadens the spectral bandwidth of 4I13/2→4I15/2 transition and lengthens the lifetime significantly from 3.5 to 4.6 ms. Fibers were fabricated by the rod-in-tube technique using a Heathway drawing tower. The emission power of these Er3+-Yb3+ co-doped Step Index Tellurite Fibers (SITFs; lengths varying from 2 to 60 cm) were generated by a 980 nm diode laser pump and then the emission power spectra were acquired with an OSA. The maximum emission power spectra, within the 1530-1560 nm region, were observed for fiber lengths ranging from 3 to 6 cm. The highest bandwidth obtained was 108 nm for 8 cm fiber length around 1.53 µm.

  15. Thermo-tunable hybrid photonic crystal fiber based on solution-processed chalcogenide glass nanolayers.

    PubMed

    Markos, Christos

    2016-01-01

    The possibility to combine silica photonic crystal fiber (PCF) as low-loss platform with advanced functional materials, offers an enormous range of choices for the development of fiber-based tunable devices. Here, we report a tunable hybrid silica PCF with integrated As2S3 glass nanolayers inside the air-capillaries of the fiber based on a solution-processed glass approach. The deposited high-index layers revealed antiresonant transmission windows from ~500 nm up to ~1300 nm. We experimentally demonstrate for the first time the possibility to thermally-tune the revealed antiresonances by taking advantage the high thermo-optic coefficient of the solution-processed nanolayers. Two different hybrid fiber structures, with core diameter 10 and 5 μm, were developed and characterized using a supercontinuum source. The maximum sensitivity was measured to be as high as 3.6 nm/°C at 1300 nm. The proposed fiber device could potentially constitute an efficient route towards realization of monolithic tunable fiber filters or sensing elements. PMID:27538726

  16. Experimental research on the penetration of tungsten-fiber/metallic-glass matrix composite material bullet into steel target

    NASA Astrophysics Data System (ADS)

    Chen, X. W.; Chen, G.

    2012-08-01

    In the present paper, the penetration experiments of tungsten-fiber/metallic-glass matrix composite material bullets into 45# steel targets are conducted by employing H25 artillery. In which, an experimental technique of sub-caliber penetration is constructed. The quasi static and dynamic behaviours of tungsten-fiber/metallic-glass matrix composite material are also experimental investigated. The self-sharpening phenomenon of composite material is observed. Integrated with metallographic analysis, the failure modes of tungsten-fiber/metallic-glass matrix composite material are identified systemically and compared with the quasi-static and dynamic material tests. It includes four failure modes, i.e., shear fracture of tungsten fiber, brittle fracture of tungsten fiber and shear fracture of metallic glass matrix as well as melting of tungsten fiber and metallic glass matrix. Comparatively, three failure mechanisms of tungsten fiber in the bullet nose are also identified, i.e., shear fracture, splitting fracture and bending or/and buckling. Finally, the mechanism of self-sharpening behaviour of tungsten-fiber/metallic-glass matrix composite material is discussed.

  17. Spectroscopy of Yb:Tm doped tellurite glasses for efficient infrared fiber laser

    NASA Astrophysics Data System (ADS)

    Gebavi, H.; Taher, M.; Lousteau, J.; Milanese, D.; Taccheo, S.; Schulzgen, A.; Ferraris, M.; Peyghambarian, N.

    2010-02-01

    We performed extensive spectroscopy of tellurite glasses doped with high concentration of Tm ions for laser emission at around 2 micron wavelength. The aim of the work is to develop a glass suitable for single-frequency fiber laser. In fact such a kind of laser require the use of short cavity length and therefore high gain per unit length medium. Tellurite glasses allows high-doping concentration and are therefore an excellent candidate. In these paper we review our recent results. In particular we address the optical and thermo-mechanical properties of several tellurite glasses (75mol%Te02.20mol%ZnO. 5mol%Na2O) with Tm3+ doping up to 111,564 ppm.

  18. Simulated and Experimental Damping Properties of a SMA/Fiber Glass Laminated Composite

    NASA Astrophysics Data System (ADS)

    Arnaboldi, S.; Bassani, P.; Biffi, C. A.; Tuissi, A.; Carnevale, M.; Lecis, N.; Loconte, A.; Previtali, B.

    2011-07-01

    In this article, an advanced laminated composite is developed, combining the high damping properties of shape memory alloy (SMA) with mechanical properties and light weight of a glass-fiber reinforced polymer. The composite is formed by stacking a glass-fiber reinforced epoxy core between two thin patterned strips of SMA alloy, and two further layers of fiber-glass reinforced epoxy. The bars of the laminated composite were assembled and cured in autoclave. The patterning was designed to enhance the interface adhesion between matrix and SMA inserts and optimally exploit the damping capacity of the SMA thin ribbons. The patterned ribbons of the SMA alloy were cut by means of a pulsed fiber laser source. Damping properties at different amplitudes on full scale samples were investigated at room temperature with a universal testing machine through dynamic tension tests, while temperature dependence was investigated by dynamic mechanical analyses (DMA) on smaller samples. Experimental results were used in conjunction with FEM analysis to optimize the geometry of the inserts. Experimental decay tests on the laminated composite have been carried out to identify the adimensional damping value related to their first flexural mode.

  19. Laser processing of glass fiber reinforced thermoplastics with different wavelengths and pulse durations

    NASA Astrophysics Data System (ADS)

    Schilling, N.; Krupop, B.; Klotzbach, U.

    2015-03-01

    In this paper, laser processing of fiber reinforced thermoplastics is investigated with different laser sources. Aim of the study is to determine the process windows in which selective ablation of polymer matrix and homogenous ablation of matrix and fiber occurs. To reach this, laser sources with different wavelengths (10600 nm, 1064 nm and 532 nm) and pulse durations in μs, ns and ps regime are compared on their ablation behavior of natural and black colored glass fiber reinforced polypropylene. Best results were achieved with ns lasers with IR wavelength at black colored material. At this parameter combination a wide process window can be shown where no damage of the reinforcing fibers happens.

  20. Low loss coupling and splicing of standard single mode fibers with all-solid soft-glass microstructured fibers for supercontinuum generation

    NASA Astrophysics Data System (ADS)

    Murawski, M.; Stepniewski, G.; Tenderenda, T.; Napierała, M.; Hołdyński, Z.; Szostkiewicz, L.; Slowikowski, M.; Szymanski, M.; Ostrowski, L.; Jaroszewicz, L. R.; Buczyński, R.; Nasiłowski, T.

    2014-03-01

    In this work we would like to present the results of low loss coupling of a novel soft glass fiber for super continuum generation with standard single mode fiber by a filament splicing method. For our experiment we used an all solid soft glass microstructured fiber (MSF) made from a composition of F2 lead-silicate glass and NC21 borosilicate glass. The structure and material properties of the fiber were optimized to achieve all normal dispersion (ND) flattened around 1560 nm, which offers two general advantages for supercontinuum generation. The ND supercontinuum avoids soliton dynamics, hence it is less sensitive to pump laser shot noise and has larger degree of coherence than supercontinuum in the anomalous dispersion range. Furthermore flattening around 1560 nm indicates optimal supercontinuum pump wavelength, which is readily available from erbium doped femtosecond fiber lasers. Using Vytran splicing station (GPX3400) we were able to achieve repeatable splice loss between a standard fused-silica single mode fiber (SMF28) and the low-melting-temperature soft glass MSF as low as 2.12 dB @1310 nm and 1.94 dB @ 1550 nm. The developed very low loss splicing technology together with the above mentioned all solid soft glass MSF advantages give very promising perspectives for commercial applications.

  1. Er/Yb co-doped oxy-fluoride glass-ceramics core/polymer cladding optical fibers

    NASA Astrophysics Data System (ADS)

    Czerska, E.; Świderska, M.

    2014-11-01

    Erbium/ytterbium co-doped glasses can be applied as NIR laser sources (1.55 μm) or optical amplifiers in this range. About hundred meters of Er/Yb co-doped oxy-fluoride glass-ceramics fibers have been drawn from a glass preform followed by controlled annealing. Processing temperatures (drawing and annealing) were selected upon thermal analysis results (DTA/DSC plots). Glass-ceramic structure was confirmed by the XRD measurements. Obtained fibers show good optical properties. As a cladding material polymer material (acrylic resin) is considered due to its low deposition temperature and suitable value of refractive index.

  2. Ferrule and use thereof for cooling a melt spun hollow glass fiber as it emerges from a spinnerette

    DOEpatents

    Brown, William E.

    1977-01-01

    An improvement in the process of melt spinning thin walled, hollow fibers from relatively low melting glasses results if cooling of the emerging fiber is accomplished by use of a thin layer of gas to transfer heat from the fiber to a ferrule which fits closely to the spinnerette face and the individual fiber. The ferrule incorporates or is in contact with a heat sink and is slotted or segmented so that it may be brought into position around the moving fiber. Thinner walled, more uniform fibers may be spun when this method of cooling is employed.

  3. In vitro study of improved wound-healing effect of bioactive borate-based glass nano-/micro-fibers.

    PubMed

    Yang, Qingbo; Chen, Sisi; Shi, Honglan; Xiao, Hai; Ma, Yinfa

    2015-10-01

    Because of the promising wound-healing capability, bioactive glasses have been considered as one of the next generation hard- and soft-tissue regeneration materials. The lack of understanding of the substantial mechanisms, however, indicates the need for further study on cell-glass interactions to better interpret the rehabilitation capability. In the present work, three bioactive glass nano-/micro-fibers, silicate-based 45S5, borate-based 13-93B3 and 1605 (additionally doped with copper oxide and zinc oxide), were firstly compared for their in vitro soaking/conversion rate. The results of elemental monitoring and electron microscopic characterization demonstrated that quicker ion releasing and glass conversion occurred in borate-based fibers than that of silicate-based one. This result was also reflected by the formation speed of hydroxyapatite (HA). This process was further correlated with original boron content and surrounding rheological condition. We showed that an optimal fiber pre-soaking time (or an ideal dynamic flow rate) should exist to stimulate the best cell proliferation and migration ability. Moreover, 13-93B3 and 1605 fibers showed different glass conversion and biocompatibility properties as well, indicating that trace amount variation in composition can also influence fiber's bioactivity. In sum, our in vitro rheological module closely simulated in vivo niche environment and proved a potentially improved wound-healing effect by borate-based glass fibers, and the results shall cast light on future improvement in bioactive glass fabrication. PMID:26117744

  4. CO2-laser-assisted processing of glass fiber-reinforced thermoplastic composites

    NASA Astrophysics Data System (ADS)

    Brecher, Christian; Emonts, Michael; Schares, Richard Ludwig; Stimpfl, Joffrey

    2013-02-01

    To fully exploit the potential of fiber-reinforced thermoplastic composites (FRTC) and to achieve a broad industrial application, automated manufacturing systems are crucial. Investigations at Fraunhofer IPT have proven that the use of laser system technology in processing FRTC allows to achieve high throughput, quality, flexibility, reproducibility and out-of-autoclave processing simultaneously. As 90% of the FRP in Europe1 are glass fiber-reinforced a high impact can be achieved by introducing laser-assisted processing with all its benefits to glass fiber-reinforced thermoplastics (GFRTC). Fraunhofer IPT has developed the diode laser-assisted tape placement (laying and winding) to process carbon fiber-reinforced thermoplastic composites (CFRTC) for years. However, this technology cannot be transferred unchanged to process milky transparent GFRTC prepregs (preimpregnated fibers). Due to the short wavelength (approx. 980 nm) and therefore high transmission less than 20% of the diode laser energy is absorbed as heat into non-colored GFRTC prepregs. Hence, the use of a different wave length, e.g. CO2-laser (10.6 μm) with more than 90% laser absorption, is required to allow the full potential of laser-assisted processing of GFRTC. Also the absorption of CO2-laser radiation at the surface compared to volume absorption of diode laser radiation is beneficial for the interlaminar joining of GFRTC. Fraunhofer IPT is currently developing and investigating the CO2-laser-assisted tape placement including new system, beam guiding, process and monitoring technology to enable a resource and energy efficient mass production of GFRP composites, e.g. pipes, tanks, masts. The successful processing of non-colored glass fiber-reinforced Polypropylene (PP) and Polyphenylene Sulfide (PPS) has already been proven.

  5. Effect of the glass transition of coating adhesive on temperature performance of fiber optic gyroscope and its optimization

    NASA Astrophysics Data System (ADS)

    Wang, Yueze; Wang, Tieshui; Ma, Lin; Yu, Hao; Liu, Bohan

    2015-10-01

    The fiber optic gyroscope (FOG)based on Sagnac effect has became to one of the most important sensors in developing due to light in quality, high accuracy, compact in dimension and long life and has played a very important role in both military and civil use. It is the most difficult problem that the FOG has an obvious bias drift caused by temperature change and temperature grade, so its application is limited to a great extent. Fiber coil is one of the most critical components in FOG. Here, the characteristic of temperature error of the fiber optical coil was analyzed. At first, by studying the glass transition of coating adhesive in the fiber coil, the element model of the fiber coil with the glass transition of coating adhesive in FOG was built. Then the discrete mathematics model of SHUPE error with the glass transition of coating adhesive in FOG was built. Finally, based on the temperature models mentioned above, the effects caused by the glass transition of coating adhesive on temperature performance of fiber optic gyroscope were analyzed. Theoretical analysis and experimental results show that effect caused by the glass transition of coating adhesive had seriously affected the temperature performance of FOG. By optimizing the glass transition temperature of coating adhesive, the SHUPE error of fiber coils can be reduced. At the same time, the amplitude uniformity of the SHUPE error can be improved greatly to reduce the difficulty in temperature compensation.

  6. Tailoring Interfacial Properties by Controlling Carbon Nanotube Coating Thickness on Glass Fibers Using Electrophoretic Deposition.

    PubMed

    Tamrakar, Sandeep; An, Qi; Thostenson, Erik T; Rider, Andrew N; Haque, Bazle Z Gama; Gillespie, John W

    2016-01-20

    The electrophoretic deposition (EPD) method was used to deposit polyethylenimine (PEI) functionalized multiwall carbon nanotube (CNT) films onto the surface of individual S-2 glass fibers. By varying the processing parameters of EPD following Hamaker's equation, the thickness of the CNT film was controlled over a wide range from 200 nm to 2 μm. The films exhibited low electrical resistance, providing evidence of coating uniformity and consolidation. The effect of the CNT coating on fiber matrix interfacial properties was investigated through microdroplet experiments. Changes in interfacial properties due to application of CNT coatings onto the fiber surface with and without a CNT-modified matrix were studied. A glass fiber with a 2 μm thick CNT coating and the unmodified epoxy matrix showed the highest increase (58%) in interfacial shear strength (IFSS) compared to the baseline. The increase in the IFSS was proportional to CNT film thickness. Failure analysis of the microdroplet specimens indicated higher IFSS was related to fracture morphologies with higher levels of surface roughness. EPD enables the thickness of the CNT coating to be adjusted, facilitating control of fiber/matrix interfacial resistivity. The electrical sensitivity provides the opportunity to fabricate a new class of sizing with tailored interfacial properties and the ability to detect damage initiation. PMID:26699906

  7. Mechanisms of optical losses in Bi:SiO2 glass fibers.

    PubMed

    Zlenko, Alexander S; Mashinsky, Valery M; Iskhakova, Ludmila D; Semjonov, Sergey L; Koltashev, Vasiliy V; Karatun, Nikita M; Dianov, Evgeny M

    2012-10-01

    The mechanisms of optical losses in bismuth-doped silica glass (Bi:SiO(2)) and fibers were studied. It was found that in the fibers of this composition the up-conversion processes occur even at bismuth concentrations lower than 0.02 at.%. Bi:SiO(2) core holey fiber drawn under oxidizing conditions was investigated. The absorption spectrum of this fiber has no bands of the bismuth infrared active center. Annealing of this fiber under reducing conditions leads to the formation of the IR absorption bands of the bismuth active center (BAC) and to the simultaneous growth of background losses. Under the realized annealing conditions (argon atmosphere, T(max) = 1100°C, duration 30 min) the BAC concentration reaches its maximum and begins to decrease in the process of excessive Bi reduction, while the background losses only increase. It was shown that the cause of these background losses is the absorption of light by nanoparticles of metallic bismuth formed in bismuth-doped glasses as a result of reduction of a part of the bismuth ions to Bi(0) and their following aggregation. The growth of background losses occurs owing to the increase of the concentration and the size of the metallic bismuth nanoparticles. PMID:23188284

  8. Application of a Fiber Optic Distributed Strain Sensor System to Woven E-Glass Composite

    NASA Technical Reports Server (NTRS)

    Anastasi, Robert F.; Lopatin, Craig

    2001-01-01

    A distributed strain sensing system utilizing a series of identically written Bragg gratings along an optical fiber is examined for potential application to Composite Armored Vehicle health monitoring. A vacuum assisted resin transfer molding process was used to fabricate a woven fabric E-glass/composite panel with an embedded fiber optic strain sensor. Test samples machined from the panel were mechanically tested in 4-point bending. Experimental results are presented that show the mechanical strain from foil strain gages comparing well to optical strain from the embedded sensors. Also, it was found that the distributed strain along the sample length was consistent with the loading configuration.

  9. Internal structure of sponge glass fiber revealed by ptychographic nanotomography.

    PubMed

    Birkbak, Mie E; Guizar-Sicairos, Manuel; Holler, Mirko; Birkedal, Henrik

    2016-04-01

    Sponge glass spicules have solicited great interest due to their mechanical and optical properties. Herein we use ptychographic nanotomography to obtain detailed insights into the internal structure of an anchor spicule from the Venus flower basket. The obtained dataset has 90nm resolution in 3D and provides quantitative determination of the electron density. The data reveal significant variations in electron density across the spicule. The central organic filament is found to be slightly but significantly displaced from the spicule central axis. Analysis of the electron density affords an estimate of a protein volume fraction in the organic filament of about 70%. In the highly mineralized part of the spicule, the electron density is seen to display circular symmetry and be neigh independent of position along the spicule long axis. Variations in the electron density beyond those included in current models of spicule mechanics are observed. PMID:26853498

  10. Fabrication of optical fiber of zinc tin borophosphate glass with zero photoelastic constant

    NASA Astrophysics Data System (ADS)

    Saitoh, Akira; Oba, Yuya; Takebe, Hiromichi

    2015-10-01

    An optical fiber made of zinc tin boro-phosphate glass having a zero photoelastic constant, good water durability, and excluding hazardous elements was drawn from a prepared preform for use in a fiber-type current sensor device. The proposed cladding compositions enable single-mode propagation for a wavelength of 1550 nm, which is estimated from the difference in the refractive index between the core and cladding compositions. The drawing conditions should be controlled since the multiple-component glass is very sensitive to changes in viscosity and crystal precipitation during the heat-treated stretching of the preform. The temperature dependence of viscosity in the core and cladding reveals the feasibility of drawing.

  11. Mechanical behavior of a glass-fiber reinforced composite to steel joint for ships

    NASA Astrophysics Data System (ADS)

    Li, Xiaowen; Li, Ping; Lin, Zhuang; Yang, Dongmei

    2015-03-01

    The use of a glass-fiber reinforced composite in marine structures is becoming more common, particularly due to the potential weight savings. The mechanical response of the joint between a glass-fiber reinforced polymer (GRP) superstructure and a steel hull formed is examined and subsequently modified to improve performance through a combined program of modeling and testing. A finite-element model is developed to predict the response of the joint. The model takes into account the contact at the interface between different materials, progressive damage, large deformation theory, and a non-linear stress-strain relationship. To predict the progressive failure, the analysis combines Hashin failure criteria and maximum stress failure criteria. The results show stress response has a great influence on the strength and bearing of the joint. The Balsawood-steel interface is proved to be critical to the mechanical behavior of the joint. Good agreement between experimental results and numerical predictions is observed.

  12. A simplified numerical simulation method of bending properties for glass fiber cloth reinforced denture base resin.

    PubMed

    Tanimoto, Yasuhiro; Nishiwaki, Tsuyoshi; Nishiyama, Norihiro; Nemoto, Kimiya; Maekawa, Zen-ichiro

    2002-06-01

    The purpose of this study was to propose a new numerical modeling of the glass fiber cloth reinforced denture base resin (GFRP). The proposed model is constructed with an isotropic shell, beam and orthotropic shell elements representing the outmost resin, interlaminar resin and glass fiber cloth, respectively. The proposed model was applied to the failure progress analysis under three-point bending conditions, the validity of the numerical model was checked through comparisons with experimental results. The failure progress behaviors involving the local failures, such as interlaminar delamination and resin failure, could be simulated using the numerical model for analyzing the failure progress of GFRP. It is concluded that the model was effective for the failure progress analysis of GFRP. PMID:12238780

  13. Optical fiber sensors using hollow glass spheres and CCD spectrometer interrogator

    NASA Astrophysics Data System (ADS)

    Dakin, John P.; Ecke, Wolfgang; Schroeder, Kerstin; Reuter, Martin

    2009-10-01

    Hollow glass micro-spheres, firstly used to make fiber optic sensors for high hydrostatic pressure, have been interrogated using a high-resolution CCD-based spectrometer, to give far better precision than conventional spectrometric read out. It is found that these simple, low-cost micro-sensors have excellent sensitivity to both static and dynamic pressure, and have the advantage of being hermetically sealed. Many other application areas are foreseen for these low-cost sensors.

  14. Nanoarchitectures based on layered titanosilicates supported on glass fibers: application to hydrogen storage.

    PubMed

    Pérez-Carvajal, Javier; Aranda, Pilar; Berenguer-Murcia, Angel; Cazorla-Amorós, Diego; Coronas, Joaquín; Ruiz-Hitzky, Eduardo

    2013-06-18

    This work reports on the synthesis of nanosheets of layered titanosilicate JDF-L1 supported on commercial E-type glass fibers with the aim of developing novel nanoarchitectures useful as robust and easy to handle hydrogen adsorbents. The preparation of those materials is carried out by hydrothermal reaction from the corresponding gel precursor in the presence of the glass support. Because of the basic character of the synthesis media, silica from the silicate-based glass fibers can be involved in the reaction, cementing its associated titanosilicate and giving rise to strong linkages on the support with the result of very stable heterostructures. The nanoarchitectures built up by this approach promote the growth and disposition of the titanosilicate nanosheets as a house-of-cards radially distributed around the fiber axis. Such an open arrangement represents suitable geometry for potential uses in adsorption and catalytic applications where the active surface has to be available. The content of the titanosilicate crystalline phase in the system represents about 12 wt %, and this percentage of the adsorbent fraction can achieve, at 298 K and 20 MPa, 0.14 wt % hydrogen adsorption with respect to the total mass of the system. Following postsynthesis treatments, small amounts of Pd (<0.1 wt %) have been incorporated into the resulting nanoarchitectures in order to improve their hydrogen adsorption capacity. In this way, Pd-layered titanosilicate supported on glass fibers has been tested as a hydrogen adsorbent at diverse pressures and temperatures, giving rise to values around 0.46 wt % at 298 K and 20 MPa. A mechanism of hydrogen spillover involving the titanosilicate framework and the Pd nanoparticules has been proposed to explain the high increase in the hydrogen uptake capacity after the incorporation of Pd into the nanoarchitecture. PMID:23270562

  15. Deposition Of Thin-Film Sensors On Glass-Fiber/Epoxy Models

    NASA Technical Reports Server (NTRS)

    Tran, Sang Q.

    1995-01-01

    Direct-deposition process devised for fabrication of thin-film sensors on three-dimensional, curved surfaces of models made of stainless steel covered with glass-fiber/epoxy-matrix composite material. Models used under cryogenic conditions, and sensors used to detect on-line transitions between laminar and turbulent flows in wind tunnel environments. Sensors fabricated by process used at temperatures from minus 300 degrees F to 175 degrees F.

  16. Effect of moisture on hammer-milled glass-fiber-reinforced polyurethane

    SciTech Connect

    Mateen, A.; Siddiqi, S.A.

    1996-10-01

    The effect of moisture on the dynamic properties of hammer-milled glass-fiber-reinforced polyurethane was investigated. Similar investigations were also made on an unfilled polyurethane matrix for comparison. Moisture was found to increase the shear modulus at lower temperature due to the formation of ice. At higher temperatures, however, shear modulus decreased due to the plasticizing effect of water. Moisture also modified the damping properties of the material.

  17. Fabrication of glass photonic crystal fibers with a die-cast process

    NASA Astrophysics Data System (ADS)

    Guiyao, Zhou; Zhiyun, Hou; Shuguang, Li; Lantian, Hou

    2006-06-01

    We demonstrate a novel method for the fabrication of glass photonic crystal fibers (PCFs) with a die-cast process. SF6 glass is used as the material for PCFs, and the die is made of heat-resisting alloy steel, whose inner structure matches the PCF's structure. The die is put vertically in the vessel with SF6 glass, and the vacuum hose is attached to the top of the die. The die and glass are put in the furnace to heat at 870 K. The die is slowly filled with the softening glass under vacuum conduction until it is full. It is kept in the furnace to anneal at a rate of 20 K/h to remove the thermal stress that could lead to cracks. The outer tube of the die is taken apart when its temperature is close to room temperature, and the fused glass bundle is etched in an acidic solution to remove the heat-resisting alloy steel rods. Thus, the etched bundle is ready to use as a PCF preform. The PCF is observed in the generation of a supercontinuum, with the flat plateau in the spectrum of the output emission stretching from 400 to 1400 nm by experimental measurement. The transmission loss is 0.2-0.3 dB/m at wavelengths of 420-900 nm.

  18. Skin problems among fiber-glass reinforced plastics factory workers in Japan.

    PubMed

    Minamoto, Keiko; Nagano, Megumi; Inaoka, Tsukasa; Kitano, Takao; Ushijima, Kayo; Fukuda, Yoshiharu; Futatsuka, Makoto

    2002-01-01

    Two surveys, one in winter the other in summer time, examined the skin problems of the entire manual workers (N=148) from 11 small-to-medium sized fiber-glass reinforced plastics (FRP) factories located in Kyushu, Japan. The workers were exposed to unsaturated polyester resin, including styrene and auxiliary agents such as cobalt naphthenate, hardeners such as methyl ethyl ketone peroxides, glass fiber and dust including shortened glass fiber and plastic particles. Eighty-seven workers (58.8%) reported having skin problems (mainly itching or dermatitis) since they started to work in FRP manufacturing and 25 workers had consulted a physician because of their skin problems; one worker was forced to take sick leave because of his severe dermatitis. History of allergic diseases and shorter occupational period (duration of employment) in a FRP factory were associated with greater probability of having a history of work-related skin symptoms. Workers in factories where dust-generating and lamination sites were located in different buildings were significantly less likely to have a history of skin problems than those in factories where the two sites were located in the same building. Of the 67 workers examined in both seasons closed to double the prevalence of dermatitis was found in summer (23.3%) than winter (13.4%). PMID:11926514

  19. Development of New Generation of Thermally-Enhanced Fiber Glass Insulation

    SciTech Connect

    Kosny, Jan; Yarbrough, David W; Childs, Phillip W; Miller, William A; Atchley, Jerald Allen; Shrestha, Som S

    2010-03-01

    This report presents experimental and numerical results from thermal performance studies. The purpose of this Cooperative Research and Development Agreement (CRADA) between UT-Battelle, LLC and John s Manville was to design a basic concept of a new generation of thermally-enhanced fiber glass insulation. Different types of Phase Change Materials (PCMs) have been tested as dynamic components in buildings during the last 4 decades. Most historical studies have found that PCMs enhance building energy performance. Some PCM-enhanced building materials, like PCM-gypsum boards or PCM-impregnated concretes have already found their limited applications in different countries. Today, continued improvements in building envelope technologies suggest that throughout Southern and Central U.S. climates, residences may soon be routinely constructed with PCM in order to maximize insulation effectiveness and maintain low heating and cooling loads. The proposed thermally-enhanced fiber glass insulation will maximize this integration by utilizing a highly-efficient building envelope with high-R thermal insulation, active thermal mass and superior air-tightness. Improved thermal resistance will come from modifications in infrared internal characteristics of the fiber glass insulation. Thermal mass effect can be provided by proprietary thermally-active microencapsulated phase change material (PCM). Work carried out at the Oak Ridge National Laboratory (ORNL) on the CRADA is described in this report.

  20. Mid-infrared surface plasmon polariton chemical sensing on fiber-coupled ITO coated glass.

    PubMed

    Martínez, Javier; Ródenas, Airán; Aguiló, Magdalena; Fernandez, Toney; Solis, Javier; Díaz, Francesc

    2016-06-01

    A novel fiber-coupled indium tin oxide (ITO) coated glass slide sensor for performing surface plasmon polariton chemical monitoring in the ∼3.5  μm mid-infrared (IR) range is reported. Efficient mid-IR fiber coupling is achieved with 3D laser written waveguides, and the coupling of glass waveguide modes to ITO surface plasmon polaritons (SPPs) is driven by the varying phase matching conditions of different aqueous analytes across the anomalous dispersion range determined by their molecular fingerprints. By means of using both a mid-IR fiber supercontinuum source and a diode laser, the excitation of SPPs is demonstrated. The sensor sensitivity is tested by discriminating CH from OH features of ethanol in water solutions, demonstrating an instrumental ethanol limit of detection of 0.02% in a wide concentration range of at least 0%-50%. The efficient optical monitoring of mid-IR SPPs in smart glass could have a broad range of applications in biological and chemical sensing. PMID:27244397

  1. Laser-diode pumped glass-clad Ti:sapphire crystal fiber laser.

    PubMed

    Wang, Shih-Chang; Hsu, Chun-Yang; Yang, Tzu-Te; Jheng, Dong-Yo; Yang, Teng-I; Ho, Tuan-Shu; Huang, Sheng-Lung

    2016-07-15

    Efficient glass-clad crystal fiber (CF) lasers were demonstrated using a Ti:sapphire crystalline core as the gain medium. With a core diameter of 18 μm, the laser diode (LD) pump source can be effectively coupled and guided throughout the crystal fiber for a low threshold and high slope efficiency laser operation. The advantage of high heat dissipation efficiency of the fiber structure can be derived from the low core temperature rising measurement (i.e., 17 K/W) with passive cooling. At an output transmittance of 23%, the lowest absorbed threshold of 118.2 mW and highest slope efficiency of 29.6% were achieved, with linear laser polarization. PMID:27420499

  2. Experimental Investigation of Low-Velocity Repeated Impacts on Glass Fiber Metal Composites

    NASA Astrophysics Data System (ADS)

    Rajkumar, G. R.; Krishna, M.; Narasimha Murthy, H. N.; Sharma, S. C.; Vishnu Mahesh, K. R.

    2012-07-01

    The aim of this study was to experimentally investigate the effect of repeated low-velocity impacts on tensile strength of fiber metal laminates (FMLs) using instrumented drop weight impact tester. FMLs were fabricated layer by layer intercalating three layers of aluminum 6061 and two layers of glass fiber-reinforced epoxy. The FMLs were subjected to repeated low-velocity impacts (<10 m/s) at the same location on the FML. The degradation of mechanical property due to impact(s) was studied using Zwick UTM at distances of 0, 20, 40, and 60 mm from the impact point. Results indicate that ultimate tensile strength, failure strain, and ductility of all specimens initially decrease, and then remain constant with increase in number of impacts. A closer examination of impacted FML by scanning electron microscope indicates that thinning and shear fracture in aluminum layers, as well as delamination, and fiber failure in composites plies were present.

  3. Highly Tm(3+) doped germanate glass and its single mode fiber for 2.0 μm laser.

    PubMed

    Wen, Xin; Tang, Guowu; Yang, Qi; Chen, Xiaodong; Qian, Qi; Zhang, Qinyuan; Yang, Zhongmin

    2016-01-01

    Highly Tm(3+) doped optical fibers are urgently desirable for 2.0 μm compact single-frequency fiber laser and high-repetition-rate mode-locked fiber laser. Here, we systematically investigated the optical parameters, energy transfer processes and thermal properties of Tm(3+) doped barium gallo-germanate (BGG) glasses. Highly Tm(3+) doped BGG glass single mode (SM) fibers were fabricated by the rod-in-tube technique. The Tm(3+) doping concentration reaches 7.6 × 10(20) ions/cm(3), being the reported highest level in Tm(3+) doped BGG SM fibers. Using ultra short (1.6 cm) as-drawn highly Tm(3+) doped BGG SM fiber, a single-frequency fiber laser at 1.95 μm has been demonstrated with a maximum output power of 35 mW when in-band pumped by a home-made 1568 nm fiber laser. Additionally, a multilongitudinal-mode fiber laser at 1.95 μm has also been achieved in a 10 cm long as-drawn active fiber, yielding a maximum laser output power of 165 mW and a slope efficiency of 17%. The results confirm that the as-drawn highly Tm(3+) doped BGG SM fibers are promising in applications that require high gain and high power from a short piece of active optical fiber. PMID:26828920

  4. Highly Tm3+ doped germanate glass and its single mode fiber for 2.0 μm laser

    PubMed Central

    Wen, Xin; Tang, Guowu; Yang, Qi; Chen, Xiaodong; Qian, Qi; Zhang, Qinyuan; Yang, Zhongmin

    2016-01-01

    Highly Tm3+ doped optical fibers are urgently desirable for 2.0 μm compact single-frequency fiber laser and high-repetition-rate mode-locked fiber laser. Here, we systematically investigated the optical parameters, energy transfer processes and thermal properties of Tm3+ doped barium gallo-germanate (BGG) glasses. Highly Tm3+ doped BGG glass single mode (SM) fibers were fabricated by the rod-in-tube technique. The Tm3+ doping concentration reaches 7.6 × 1020 ions/cm3, being the reported highest level in Tm3+ doped BGG SM fibers. Using ultra short (1.6 cm) as-drawn highly Tm3+ doped BGG SM fiber, a single-frequency fiber laser at 1.95 μm has been demonstrated with a maximum output power of 35 mW when in-band pumped by a home-made 1568 nm fiber laser. Additionally, a multilongitudinal-mode fiber laser at 1.95 μm has also been achieved in a 10 cm long as-drawn active fiber, yielding a maximum laser output power of 165 mW and a slope efficiency of 17%. The results confirm that the as-drawn highly Tm3+ doped BGG SM fibers are promising in applications that require high gain and high power from a short piece of active optical fiber. PMID:26828920

  5. Highly Tm3+ doped germanate glass and its single mode fiber for 2.0 μm laser

    NASA Astrophysics Data System (ADS)

    Wen, Xin; Tang, Guowu; Yang, Qi; Chen, Xiaodong; Qian, Qi; Zhang, Qinyuan; Yang, Zhongmin

    2016-02-01

    Highly Tm3+ doped optical fibers are urgently desirable for 2.0 μm compact single-frequency fiber laser and high-repetition-rate mode-locked fiber laser. Here, we systematically investigated the optical parameters, energy transfer processes and thermal properties of Tm3+ doped barium gallo-germanate (BGG) glasses. Highly Tm3+ doped BGG glass single mode (SM) fibers were fabricated by the rod-in-tube technique. The Tm3+ doping concentration reaches 7.6 × 1020 ions/cm3, being the reported highest level in Tm3+ doped BGG SM fibers. Using ultra short (1.6 cm) as-drawn highly Tm3+ doped BGG SM fiber, a single-frequency fiber laser at 1.95 μm has been demonstrated with a maximum output power of 35 mW when in-band pumped by a home-made 1568 nm fiber laser. Additionally, a multilongitudinal-mode fiber laser at 1.95 μm has also been achieved in a 10 cm long as-drawn active fiber, yielding a maximum laser output power of 165 mW and a slope efficiency of 17%. The results confirm that the as-drawn highly Tm3+ doped BGG SM fibers are promising in applications that require high gain and high power from a short piece of active optical fiber.

  6. Nanostructuring an erbium local environment inside sol-gel silica glasses: toward efficient erbium optical fiber lasers

    NASA Astrophysics Data System (ADS)

    Savelii, Inna; El Hamzaoui, Hicham; Bigot, Laurent; Bouwmans, Géraud; Fsaifes, Ihsan; Capoen, Bruno; Bouazaoui, Mohamed

    2016-02-01

    To extend the use of erbium- (Er-)/aluminum- (Al-) codoped optical fibers in hostile environments, the reduction of the Al amount has been identified as a serious way to harden them against harsh radiation. In this work, sol-gel monolithic Er3+-doped and Er3+/Al3+-codoped silica glasses were prepared from nanoporous silica xerogels soaked in a solution containing an Er salt together or not with an Al salt. After sintering, these glasses were used as the core material of microstructured optical fibers made by the stack-and-draw method. The influence of Al incorporation on the optical properties of Er3+-doped silica glasses and fibers is investigated. This approach enabled the preparation of silica glasses containing dispersed Er3+ ions with low Al content. The obtained fibers have been tested in an all-fibered cavity laser architecture. The Er3+/Al3+-codoped fiber laser presents a maximum efficiency of 27% at 1530 nm. We show that without Al doping, the laser exhibits lower performances that depend on Er content inside the doped fiber core. The effect of Er pair-induced quenching also has been investigated through nonsaturable absorption experiments, which clearly indicate that the fraction of Er ion pairs is significantly reduced in the Al-codoped fiber.

  7. The effects of embedded piezoelectric fiber composite sensors on the structural integrity of glass-fiber-epoxy composite laminate

    NASA Astrophysics Data System (ADS)

    Konka, Hari P.; Wahab, M. A.; Lian, K.

    2012-01-01

    Piezoelectric fiber composite sensors (PFCSs) made from micro-sized lead zirconate titanate (PZT) fibers have many advantages over the traditional bulk PZT sensors for embedded sensor applications. PFCSs as embedded sensors will be an ideal choice to continuously monitor the stress/strain levels and health conditions of composite structures. PFCSs are highly flexible, easily embeddable, have high compatibility with composite structures, and also provides manufacturing flexibility. This research is focused on examining the effects of embedding PFCS sensors (macro-fiber composite (MFC) and piezoelectric fiber composite (PFC)) on the structural integrity of glass-fiber-epoxy composite laminates. The strengths of composite materials with embedded PFCSs and conventional PZT sensors were compared, and the advantages of PFCS sensors over PZTs were demonstrated. Initially a numerical simulation study is performed to understand the local stress/strain field near the embedded sensor region inside a composite specimen. High stress concentration regions were observed near the embedded sensor corner edge. Using PFCS leads to a reduction of 56% in longitudinal stress concentration and 38% in transverse stress concentration, when compared to using the conventional PZTs as embedded sensors. In-plane tensile, in-plane tension-tension fatigue, and short beam strength tests are performed to evaluate the strengths/behavior of the composite specimens containing embedded PFCS. From the tensile test it is observed that embedding PFCS and PZT sensors in the composite structures leads to a reduction in ultimate strength by 3 and 6% respectively. From the fatigue test results it is concluded that both embedded PFCS and PZT sensors do not have a significant effect on the fatigue behavior of the composite specimens. From the short beam strength test it is found that embedding PFCS and PZT sensors leads to a reduction in shear strength by 7 and 15% respectively. Overall the pure PZT sensors

  8. Fracture Resistance of Endodontically-treated Maxillary Premolars Restored with Composite Resin along with Glass Fiber Insertion in Different Positions

    PubMed Central

    Jafari Navimipour, Elmira; Ebrahimi Chaharom, Mohammad Esmaeel; Alizadeh Oskoee, Parnian; Mohammadi, Narmin; Bahari, Mahmoud; Firouzmandi, Maryam

    2012-01-01

    Background and aims The aim was to evaluate the effect of three methods of fiber insertion on fracture resistance of root-filled maxillary premolars in vitro. Materials and methods Sixty extracted human maxillary premolars received endodontic treatment followed by preparation of mesioocclusodistal (MOD) cavities, with gingival cavosurface margin 1.5 mm coronal to the cementoenamel junction (CEJ). Subsequently, the samples were randomly divided into four groups: no-fiber group; occlusal fiber group (fiber was placed in the occlusal third); circumferential fiber group (fiber was placed circumferentially in the cervical third); and dual-fiber group (occlusal and circumferential fibers). Subsequent to restoring with composite resin and thermocycling, a compressive force was applied until fracture. Data was analyzed using one-way ANOVA and Tukey test at significance levels of P < 0.05 and P < 0.02, respectively. Results Fiber placement significantly increased fracture resistance. Fracture resistance in the dual-fiber group was significantly higher than that in the circumferential fiber group (P < 0.007); however, there were no significant differences between the dual-fiber and occlusal fiber groups (P = 0.706). The highest favorable fracture rate was observed in the circumferential fiber group (60%). Conclusion Composite resin restoration along with glass fiber in the occlusal and gingival thirds can be an acceptable treatment option for restoring root-filled upper premolars. PMID:23277858

  9. Yb3+-doped large core silica fiber for fiber laser prepared by glass phase-separation technology.

    PubMed

    Chu, Yingbo; Ma, Yunxiu; Yang, Yu; Liao, Lei; Wang, Yibo; Hu, Xiongwei; Peng, Jinggang; Li, Haiqing; Dai, Nengli; Li, Jinyan; Yang, Luyun

    2016-03-15

    We report on the preparation and optical characteristics of an Yb3+-doped large core silica fiber with the active core prepared from nanoporous silica rod by the glass phase-separation technology. The measurements show that the fiber has an Yb3+ concentration of 9811 ppm by weight, a low background attenuation of 0.02 dB/m, and absorption from Yb3+ about 5.5 dB/m at 976 nm. The laser performance presents a high slope efficiency of 72.8% for laser emission at 1071 nm and a low laser threshold of 3 W within only 2.3 m fiber length. It is suggested that the glass phase-separation technology shows great potential for realizing active fibers with larger core and complex fiber designs. PMID:26977675

  10. Spectroscopic properties of Nd, Er codoped glasses for solar pumped fiber lasers

    NASA Astrophysics Data System (ADS)

    Mizuno, Shintaro; Ito, Hiroshi; Hasegawa, Kazuo; Kawai, Hiroyuki; Nasu, Hiroyuki; Hughes, Mark A.; Suzuki, Takenobu; Ohishi, Yasutake

    2011-03-01

    The absorption and fluorescence characteristics of Er doped and Nd, Er codoped fluoride glasses were investigated under illumination of the simulated sunlight, laser or a monochromatic light filtered from a Xe lamp. Er was used as a sensitizing agent enhancing the energy conversion and the emission efficiency of Nd ions in fluoride glass intended for the sunlight excitation. Er doped fluoride glasses showed four emission peaks under simulated sunlight illumination at the wavelengths of 550, 848, 980, and 1530 nm attributed to the electronic transitions of Er3+ ions. The quantum efficiency of the emission from all of the bands had a peak at x = 0.5 mol. % Er and with the maximum of 73 %. The intensity of each emission band showed different ratios for various ErF3 contents. It is expected that concentration quenching of 4S3/2 state is easy to occur with high concentration of ErF3 compared to the other states. The energy transfer from Er to Nd was studied using a monochromatic light illumination which is absorbed by Er3+ ions only. Strong contribution of Er absorption to the 1.05 μm emission of Nd, Er co-doped fluoride glass was observed. Er was confirmed as a suitable sensitizer for the enhanced energy conversion and emission efficiency of Nd ions in ZBLAN glasses which are proposed for highly efficient solar pumped fiber lasers.

  11. Color stability of laboratory glass-fiber-reinforced plastics for esthetic orthodontic wires

    PubMed Central

    Inami, Toshihiro; Minami, Naomi; Yamaguchi, Masaru; Kasai, Kazutaka

    2015-01-01

    Objective In our previous study, glass-fiber-reinforced plastics (GFRPs) made from polycarbonate and glass fibers were prepared for esthetic orthodontic wires using pultrusion. These laboratory GFRP wires are more transparent than the commercially available nickel-titanium wire; however, an investigation of the color stability of GFRP during orthodontic treatment is needed. Accordingly, in the present study, the color stability of GFRP was assessed using colorimetry. Methods Preparation of GFRP esthetic round wires (diameter: 0.45 mm [0.018 inch]) using pultrusion was described previously. Here, to investigate how the diameter of fiber reinforcement affects color stability, GFRPs were prepared by incorporating either 13-µm (GFRP-13) or 7-µm glass (GFRP-7) fibers. The color changes of GFRPs after 24 h, and following 1, 2, and 4 weeks of coffee immersion at 37℃, were measured by colorimetry. We evaluated the color stability of GFRPs by two evaluating units: the color difference (ΔE*) and National Bureau of Standards (NBS). Results After immersion, both GFRPs showed almost no visible color change. According to the colorimetry measurements, the ΔE* values of GFRP-13 and GFRP-7 were 0.73-1.16, and 0.62-1.10, respectively. In accordance with NBS units, both GFRPs showed "slight" color changes. As a result, there were no significant differences in the ΔE* values or NBS units for GFRP-13 or GFRP-7. Moreover, for both GFRPs, no significant differences were observed in any of the immersion periods. Conclusions Our findings suggest that the GFRPs will maintain high color stability during orthodontic treatment, and are an attractive prospect as esthetic orthodontic wires. PMID:26023541

  12. Robust multimaterial tellurium-based chalcogenide glass fibers for mid-wave and long-wave infrared transmission.

    PubMed

    Tao, Guangming; Shabahang, Soroush; Ren, He; Khalilzadeh-Rezaie, Farnood; Peale, Robert E; Yang, Zhiyong; Wang, Xunsi; Abouraddy, Ayman F

    2014-07-01

    We describe an approach for producing robust multimaterial chalcogenide glass fibers for mid-wave and long-wave mid-infrared transmission. By combining the traditional rod-in-tube process with multimaterial coextrusion, we prepare a hybrid glass-polymer preform that is drawn continuously into a robust step-index fiber with a built-in, thermally compatible polymer jacket. Using tellurium-based chalcogenides, the fibers have a transparency window covering the 3-12 μm spectral range, making them particularly attractive for delivering quantum cascade laser light and in space applications. PMID:24978794

  13. Supercontinuum generation enhancement in all-solid all-normal dispersion soft glass photonic crystal fiber pumped at 1550 nm

    NASA Astrophysics Data System (ADS)

    Siwicki, Bartłomiej; Klimczak, Mariusz; Stępień, Ryszard; Buczyński, Ryszard

    2015-10-01

    We study supercontinuum generation enhancement in an all-normal dispersion, all-glass photonic crystal fiber made of lead-silicate glasses. Dispersion characteristics were optimized through adjustment of regular hexagonal lattice of photonic crystal fiber in case of three different, thermally matched pairs of glasses. Supercontinuum generation was simulated with split-step Fourier method using the model that takes into account frequency-dependent effective mode area and losses, Raman response of the medium and temporal shape of the input pulse. An octave-spanning coherent supercontinuum has been obtained for all-glass fiber with lattice constant Λ = 1.73 μm and filling factor d/Λ = 0.8, made of silicate SF6/F2, spanning 850-2200 nm wavelengths in 10 dB dynamic range and pumped with pulses with energy as low as 3 nJ at 1550 nm.

  14. High modulus rare earth and beryllium containing silicate glass compositions. [for glass reinforcing fibers

    NASA Technical Reports Server (NTRS)

    Bacon, J. F. (Inventor)

    1976-01-01

    Glass compositions having a Young's modulus of at least 16 million psi and a specific modulus of at least 110 million inches consisting essentially of approximately, by weight, 20 to 43% SiO2, 8 to 21% Al2O3, 4 to 10% BeO, 27 to 58% of at least one oxide selected from a first group consisting of Y2O3, La2O3, Nd2O3, Ce2O3, Ce2O3, and the mixed rare earth oxides, and 3 to 12% of at least one oxide selected from a second group consisting of MgO, ZrO2, ZnO and CaO are described. The molar ratio of BeO to the total content of the first group oxides is from 1.0 to 3.0.

  15. Improvement of fatigue life and prevention of internal crack initiation of chopped carbon fiber reinforced plastics modified with micro glass fibers

    NASA Astrophysics Data System (ADS)

    Fujitani, Ryohei; Okubo, Kazuya; Fujii, Toru

    2016-04-01

    The purpose of this study is to improve fatigue properties of chopped carbon fiber reinforced plastics fabricated by SMC (Sheet Molding Compound) method and to clarify the mechanism for improvement. To enhance the properties, micro glass fibers with 500nm in diameter were added directly into vinyl ester resin with 0.3wt% contents. The chopped carbon fiber reinforced plastics were fabricated and cured at room temperature for 1hour under 1MPa and then at 60degree-C for 3hours. After curing, the fabricated plate was cut into the dimension of specimen. Tensile and bending strength and fatigue life of chopped carbon fiber reinforced plastics were investigated by tensile and three point bending test and cyclic tension-tension test, respectively. The behavior of strain concentration around the tips of carbon fiber were discussed with model specimen on the observations with DIC (Digital Image Correlation) method and polarizing microscope under tensile loading, in which one chopped carbon fiber was embedded into the matrix. In conclusion, when toughened vinyl ester resin modified with micro glass fibers was used as matrix, tensile and bending strength and fatigue life of chopped carbon fiber reinforced plastics were increased 56.6%, 49.8% and 14 to 23 times compared with those of unmodified specimens. It should be explained that static and dynamic properties of chopped carbon fiber reinforced plastics were improved by that crack initiation and propagation were prevented according to the prevention of the locally increasing of strain around the tip of carbon fiber, when vinyl ester resin modified with micro glass fibers was used as matrix.

  16. Stress generated by customized glass fiber posts and other types by photoelastic analysis.

    PubMed

    Bosso, Kátia; Gonini Júnior, Alcides; Guiraldo, Ricardo Danil; Berger, Sandrine Bittencourt; Lopes, Murilo Baena

    2015-01-01

    Endodontic posts are necessary to provide adequate retention and support when no sufficient remaining structure is available to retain the core. There are different materials and techniques to construct post-and-core, but there is no consensus about which one promotes better stress distribution on the remaining tooth structure. This study aimed to quantify and evaluate the distribution of stress in the root produced by customized glass fiber posts compared to different endodontic posts. Twenty-five simulated roots from photoelastic resin were made and divided into 5 groups: CPC, cast post-and-core; SP, screw post; CF, carbon fiber post; GF, glass fiber post; and CGF, customized glass fiber post. After cementing CPC and SP posts with zinc phosphate cement, and CF, GF and CGF posts with resin cement, resin cores were made for groups 2-5. Specimens were evaluated with vertical or 45° oblique loading. To analyze the fringes, the root was divided into 6 parts: palatal cervical, palatal middle, palatal apical, vestibular cervical, vestibular middle, and vestibular apical. The formed fringes were photographed and quantified. Data were recorded and subjected to two-way ANOVA and Tukey's test (5%). SP (1.95±0.60) showed higher stress (p<0.05) compared to the others (CPC-0.52±0.74; CF-0.50±0.75, GF-0.23±0.48 and CGF-0.45±0.83). All posts showed high stress in apical third (CPC-1.40±0.65; SP-2.30±0.44, CF-1.80±0.45, GF-1.20±0.45, CGF-1.70±1.03) Low stress was found in cervical third (CPC-0.20±0.45; CF-0.00±0.00, GF-0.00±0.00, CGF-0.00±0.00), except by SP (1.90±0.65), which showed statistical difference (p<0.05). Customized post showed high stress concentration at the root and conventional glass fiber posts showed more favorable biomechanical behavior. PMID:26200144

  17. Analysis of temperature distribution during tension test of glass fiber reinforced plastic by fiber orientation variation.

    PubMed

    Kim, Jin-Woo; Kim, Hyoung-Seok; Lee, Dong-Gi

    2014-10-01

    In this paper, analysis of temperature distribution by fiber orientation variation under tension test was proposed through IR thermography camera. Lock-in method, which is one of technique in IR thermography camera to measure minute change in temperature, was utilized to monitor temperature distribution and change during crack propagation. Method to analyze of temperature distribution by fiber orientation variation under tension test of GFRP via IR thermography camera was suggested. At the maximum stress point, temperature was significantly increased. As shown previously, specimen with shorter fracture time showed abrupt increment of temperature at the maximum stress point. Specimen with longer fracture time displayed increment of temperature after the maximum stress point. PMID:25942822

  18. A portable microcolumn based on silver nanoparticle functionalized glass fibers and its SERS application.

    PubMed

    Gu, Hai-Xin; Li, Da-Wei; Xue, Lin; Zhang, Yong-Feng; Long, Yi-Tao

    2015-12-01

    We presented a facile method for the preparation of a portable detection column integrated with silver nanoparticle (Ag NP) functionalized glass fibers for surface-enhanced Raman scattering (SERS). Ag NPs were immobilized onto the surface of fibers through a two-step self-assembly process, and the cycling of the assembly process was repeated to optimize the SERS activity. The optimized fibers coated with homogeneous and dense Ag NPs were combined with a glass column, displaying good reproducibility. This combination could construct more "hot spots" and the spatial intra-channel structure for high mass transfer, and provide more sufficient interactions between the probing laser and metallic nanoparticles. The capability of the prepared column to have high sensitivity to dyes was demonstrated by the measurements of rhodamine 6G, alizarin red and methyl orange, with low concentrations of 28 pM, 64 pM and 0.36 nM, respectively. The SERS-active column fabricated by a facile, low-cost and high-yield approach is expected to be an effective and practical means for on-site application when rapid separation and detection of analytes in the liquid sample is needed. PMID:26488907

  19. Flexural Properties of E Glass and TR50S Carbon Fiber Reinforced Epoxy Hybrid Composites

    NASA Astrophysics Data System (ADS)

    Dong, Chensong; Sudarisman; Davies, Ian J.

    2013-01-01

    A study on the flexural properties of E glass and TR50S carbon fiber reinforced hybrid composites is presented in this paper. Specimens were made by the hand lay-up process in an intra-ply configuration with varying degrees of glass fibers added to the surface of a carbon laminate. These specimens were then tested in the three-point bend configuration in accordance with ASTM D790-07 at three span-to-depth ratios: 16, 32, and 64. The failure modes were examined under an optical microscope. The flexural behavior was also simulated by finite element analysis, and the flexural modulus, flexural strength, and strain to failure were calculated. It is shown that although span-to-depth ratio shows an influence on the stress-strain relationship, it has no effect on the failure mode. The majority of specimens failed by either in-plane or out-of-plane local buckling followed by kinking and splitting at the compressive GFRP side and matrix cracking combined with fiber breakage at the CFRP tensile face. It is shown that positive hybrid effects exist for the flexural strengths of most of the hybrid configurations. The hybrid effect is noted to be more obvious when the hybrid ratio is small, which may be attributed to the relative position of the GFRP layer(s) with respect to the neutral plane. In contrast to this, flexural modulus seems to obey the rule of mixtures equation.

  20. Damage and failure mechanisms of continuous glass fiber reinforced polyphenylene sulfide

    NASA Technical Reports Server (NTRS)

    Chen, F.; Hiltner, A.; Baer, E.

    1992-01-01

    The damage that accompanies flexural deformation of a unidirectional glass fiber composite of polyphenylene sulfide was examined by AE and SEM. These complementary techniques were used to identify damage mechanisms at the microscale and correlate them with the macroscopic stress state in four-point bending. The flexural stress-strain curve was nominally linear to about 1.0 percent strain, but the onset of damage detectable by AE occurred at 0.3 percent strain. Two peaks in the AE amplitude distribution were observed at 35 dB and 60 dB. Low-amplitude events were detected along the entire length of the specimen, and correlation with direct observations of damage made by deforming the composite on the SEM stage suggested that these events arose from matrix cracking and fiber debonding concentrated at flaws on the composite. High amplitude events occurred primarily in the region of highest flexural stress between the inner loading points. They were attributed to fracture of glass fibers on the tension side and surface damage on the compressive side.

  1. Irreversible deformation processes in PVC and its short glass fiber reinforced composites

    SciTech Connect

    Yuan, J.Y.

    1985-01-01

    The tensile mechanical behavior of PVC and its short glass fiber reinforced composites under superimposed hydrostatic pressure was studied up to 3 x 10/sup 8/ Pa. For rigid PVC, the brittle-to-ductile transition was observed at a pressure between 1 x 10/sup 7/ Pa and 2 x 10/sup 7/ Pa. This pressure-induced brittle-to-ductile transition was controlled by the competitive microdeformation processes of crazing and shear banding. Deformation in the post-yield region occurred by neck formation and subsequent drawing to produce chain orientation. A strong environmental stress-cracking effect was observed when PVC samples were exposed to the pressure-transmitting fluid, silicone oil. Three types of pressure dependent deformation processes was observed for the short glass fiber reinforced composites of PVC. Type I behavior shows debonding at the interface between fiber and matrix followed by brittle fracture of the matrix. Type II behavior, which was observed for the first time, exhibits a sharp stress drop due to debonding at the interface followed by matrix shear yielding. In Type III behavior, only upper shear yielding of matrix was observed. The transitional behavior from Type I and Type II was controlled by the pressure induced brittle to ductile transition of the matrix, while the Type II-III transition was strongly affected by debonding at the interface.

  2. Composite laminate veneers with a continuous inorganic phase comprising microporous sintered glass fiber networks.

    PubMed

    Ehrnford, L

    1983-10-01

    Veneers were made from sheets consisting of a three-dimensional network of sintered ultrafine glass fibers. The sheets were molded by a vacuum-pressure technique and then impregnated with a liquid resin. Impregnation was performed with a method that enabled the depth of penetration to be monitored. The resin was cured with UV radiation under N2 protection. By the use of TiO2-containing resins the veneer achieved an enamel-like appearance. An in vitro toothbrush dentifrice abrasion test showed a high wear resistance and persisting surface luster. Scanning electron and light microscopy showed fairly smooth and flat light-reflecting glass structures in the surface. PMID:6362318

  3. 1 mJ single-rod fiber Er:glass laser for rangefinding

    NASA Astrophysics Data System (ADS)

    Mak, Andrey A.; Polyakov, Vadim M.; Vitkin, Vladimir V.; Kharitonov, Artem A.; Buchenkov, Vyacheslav A.; Rodionov, Andrey Y.; Alekseeva, Irina P.; Dymshits, Olga S.; Zhilin, Alexander A.

    2015-02-01

    We demonstrate a compact Er:glass single-rod fiber laser for rangefinding with 1 mJ energy Q-switched at 1.54μm. Double-pass pumping with 16 W power and 5 ms pulse duration was used. Active medium was enveloped with diffuse reflector. Thus efficient output power operation achieved. Free-running mode output pulse energy was 12 mJ with a slope efficiency of 16%. Transparent glass-ceramics containing Co2+:MgAl2O4 nanocrystals were selected as the optimal passive gate to ensure Q-switching in a temperature range and transverse mode selection. The Q-switch mode had steady operation at 1 Hz repetition rate with thermal effects playing no visible role.

  4. Tm3+ doped Ga-As-S chalcogenide glasses and fibers

    NASA Astrophysics Data System (ADS)

    Galstyan, A.; Messaddeq, S. H.; Fortin, V.; Skripachev, I.; Vallée, R.; Galstian, T.; Messaddeq, Y.

    2015-09-01

    Tm3+ doped Ga-As-S chalcogenide glass samples were produced using As2S3 pure glass as starting materials. Their photoluminescence properties were characterized and strong emission bands were observed at 1.2 μm (1H5 → 3H6), 1.4 μm (3H4 → 3F4) and 1.8 μm (3F4 → 3H6) under excitation wavelengths of 698 nm and 800 nm. The thulium and gallium concentrations were optimized to achieve the highest photoluminescence efficiency. From the optimal composition, a Tm3+ doped Ga-As-S fiber was drawn and its optical properties were studied.

  5. Abrasive Wear Performance of Aluminium Modified Epoxy-Glass Fiber Composites

    NASA Astrophysics Data System (ADS)

    Kamble, Vikram G.; Mishra, Punyapriya; Al Dabbas, Hassan A.; Panda, H. S.; Fernandez, Johnathan Bruce

    2015-07-01

    For a long time, Aluminum filled epoxies molds have been used in rapid tooling process. These molds are very economical when applied in manufacturing of low volume of plastic parts. To improve the thermal conductivity of the material, the metallic filler material is added to it and the glass fiber improves the wear resistance of the material. These two important parameters establish the life of composites. The present work reports on abrasive wear behavior of Aluminum modified epoxy and glass fiber composite with 5 wt.% and 10 wt.% of aluminum particles. Through pin on disc wear testing machine, we studied the wear behaviors of composites, and all these samples were fabricated by using hand layup process. Epoxy resin was used as matrix material which was reinforced with Glass fiber and Aluminum as filler. The composite with 5 wt.% and 10 wt.% of Al was cast with dimensions 100 × 100 × 6 mm. The specimens were machined to a size of 6 × 6 × 4 mm for abrasive testing. Abrasive tests were carried out for different grit paper sizes, i.e., 150, 320, 600 at different sliding distance, i.e., 20, 40, 60 m at different loads of 5, 10 and 15 N and at constant speed. The weight loss due to wear was calculated along with coefficient of friction. Hardness was found using Rockwell hardness machine. The SEM morphology of the worn out surface wear was analyzed to understand the wear mechanism. Results showed that the addition of Aluminum particles was beneficial for low abrasive conditions.

  6. Glass fibers and vapor phase components of cigarette smoke as cofactors in experimental respiratory tract carcinogenesis

    SciTech Connect

    Feron, V.J.; Kuper, C.F.; Spit, B.J.; Reuzel, P.G.; Woutersen, R.A.

    1985-01-01

    Syrian golden hamsters were given intratracheal instillations of glass fibers with or without BP suspended in saline, once a fortnight for 52 weeks; the experiment was terminated at week 85. No tumors of the respiratory tract were observed in hamsters treated with glass fibers alone. There was no indication that glass fibers enhanced the development of respiratory tract tumors induced by BP. In another study Syrian golden hamsters were exposed to fresh air or to a mixture of 4 major vapor phase components of cigarette smoke, viz. isoprene (800----700 ppm), methyl chloride (1000----900 ppm), methyl nitrite (200----190 ppm) and acetaldehyde (1400----1200 ppm) for a period of at most 23 months. Some of the animals were also given repeated intratracheal instillations of BP or norharman in saline. Laryngeal tumors were found in 7/31 male and 6/32 female hamsters exposed only to the vapor mixture, whereas no laryngeal tumors occurred in controls. The tumor response of the larynx most probably has to be ascribed entirely to the action of acetaldehyde. Simultaneous treatment with norharman or BP did not affect the tumor response of the larynx. Acetaldehyde may occur in the vapor phase of cigarette smoke at levels up to 2000 ppm. Chronic inhalation exposure of rats to acetaldehyde at levels of 0 (controls), 750, 1500 or 3000----1000 ppm resulted in a high incidence of nasal carcinomas, both squamous cell carcinomas of the respiratory epithelium and adenocarcinomas of the olfactory epithelium. It was discussed that acetaldehyde may significantly contribute to the induction of bronchogenic cancer by cigarette smoke in man.

  7. Microstructure and mechanical behavior of metallic glass fiber-reinforced Al alloy matrix composites

    PubMed Central

    Wang, Z.; Georgarakis, K.; Nakayama, K. S.; Li, Y.; Tsarkov, A. A.; Xie, G.; Dudina, D.; Louzguine-Luzgin, D. V.; Yavari, A. R.

    2016-01-01

    Metallic glass-reinforced metal matrix composites are an emerging class of composite materials. The metallic nature and the high mechanical strength of the reinforcing phase offers unique possibilities for improving the engineering performance of composites. Understanding the structure at the amorphous/crystalline interfaces and the deformation behavior of these composites is of vital importance for their further development and potential application. In the present work, Zr-based metallic glass fibers have been introduced in Al7075 alloy (Al-Zn-Mg-Cu) matrices using spark plasma sintering (SPS) producing composites with low porosity. The addition of metallic glass reinforcements in the Al-based matrix significantly improves the mechanical behavior of the composites in compression. High-resolution TEM observations at the interface reveal the formation of a thin interdiffusion layer able to provide good bonding between the reinforcing phase and the Al-based matrix. The deformation behavior of the composites was studied, indicating that local plastic deformation occurred in the matrix near the glassy reinforcements followed by the initiation and propagation of cracks mainly through the matrix. The reinforcing phase is seen to inhibit the plastic deformation and retard the crack propagation. The findings offer new insights into the mechanical behavior of metal matrix composites reinforced with metallic glasses. PMID:27067824

  8. Microstructure and mechanical behavior of metallic glass fiber-reinforced Al alloy matrix composites.

    PubMed

    Wang, Z; Georgarakis, K; Nakayama, K S; Li, Y; Tsarkov, A A; Xie, G; Dudina, D; Louzguine-Luzgin, D V; Yavari, A R

    2016-01-01

    Metallic glass-reinforced metal matrix composites are an emerging class of composite materials. The metallic nature and the high mechanical strength of the reinforcing phase offers unique possibilities for improving the engineering performance of composites. Understanding the structure at the amorphous/crystalline interfaces and the deformation behavior of these composites is of vital importance for their further development and potential application. In the present work, Zr-based metallic glass fibers have been introduced in Al7075 alloy (Al-Zn-Mg-Cu) matrices using spark plasma sintering (SPS) producing composites with low porosity. The addition of metallic glass reinforcements in the Al-based matrix significantly improves the mechanical behavior of the composites in compression. High-resolution TEM observations at the interface reveal the formation of a thin interdiffusion layer able to provide good bonding between the reinforcing phase and the Al-based matrix. The deformation behavior of the composites was studied, indicating that local plastic deformation occurred in the matrix near the glassy reinforcements followed by the initiation and propagation of cracks mainly through the matrix. The reinforcing phase is seen to inhibit the plastic deformation and retard the crack propagation. The findings offer new insights into the mechanical behavior of metal matrix composites reinforced with metallic glasses. PMID:27067824

  9. Microstructure and mechanical behavior of metallic glass fiber-reinforced Al alloy matrix composites

    NASA Astrophysics Data System (ADS)

    Wang, Z.; Georgarakis, K.; Nakayama, K. S.; Li, Y.; Tsarkov, A. A.; Xie, G.; Dudina, D.; Louzguine-Luzgin, D. V.; Yavari, A. R.

    2016-04-01

    Metallic glass-reinforced metal matrix composites are an emerging class of composite materials. The metallic nature and the high mechanical strength of the reinforcing phase offers unique possibilities for improving the engineering performance of composites. Understanding the structure at the amorphous/crystalline interfaces and the deformation behavior of these composites is of vital importance for their further development and potential application. In the present work, Zr-based metallic glass fibers have been introduced in Al7075 alloy (Al-Zn-Mg-Cu) matrices using spark plasma sintering (SPS) producing composites with low porosity. The addition of metallic glass reinforcements in the Al-based matrix significantly improves the mechanical behavior of the composites in compression. High-resolution TEM observations at the interface reveal the formation of a thin interdiffusion layer able to provide good bonding between the reinforcing phase and the Al-based matrix. The deformation behavior of the composites was studied, indicating that local plastic deformation occurred in the matrix near the glassy reinforcements followed by the initiation and propagation of cracks mainly through the matrix. The reinforcing phase is seen to inhibit the plastic deformation and retard the crack propagation. The findings offer new insights into the mechanical behavior of metal matrix composites reinforced with metallic glasses.

  10. Effect of gamma radiation on the mechanical properties of natural silk fiber and synthetic E-glass fiber reinforced polypropylene composites: A comparative study

    NASA Astrophysics Data System (ADS)

    Shubhra, Quazi T. H.; Alam, A. K. M. M.

    2011-11-01

    Silk is a strong natural proteinous fiber and E-glass is a very strong synthetic fiber. Compression molding method was used to fabricate B. mori silk fiber reinforced polypropylene (PP) matrix composites. The tensile strength (TS), tensile modulus (TM), bending strength (BS), bending modulus (BM) and impact strength (IS) of prepared composites were 55.1 MPa, 780 MPa, 56.3 MPa, 3450 MPa and 17 kJ/m 2, respectively. Synthetic E-glass fiber reinforced PP based composites were fabricated in the same way and TS, TM, BS, BM, IS of E-glass fiber reinforced polypropylene composites were found to be 128.7 MPa, 4350 MPa, 141.6 MPa, 6300 MPa and 19 kJ/m 2, respectively. Gamma radiation is high energy ionizing radiation and was applied to increase the mechanical properties of the composites. Application of gamma ray increases the mechanical properties of silk/PP composites to a greater extent than that of E-glass/PP composites.

  11. Tailoring the interface in S-glass fiber polycarbonate composites for dental applications

    NASA Astrophysics Data System (ADS)

    Ranade, Shrirang Vijay

    1997-08-01

    Continuous S-Glass fiber reinforced polycarbonate composites have been evaluated clinically for orthodontic applications. It was found that the stability of the fiber/matrix interfaces in the oral environment was essential for satisfactory performance. To achieve maximum hydrolytic stability, polycarbonate oligomers were chemically grafted onto the glass fiber surface through use of a silicon tetrachloride intermediary. The interfacial shear strength, fracture toughness and hydrolytic stability of the resulting interphase was measured and compared to those of two commercial sizings and ozone cleaned surfaces. Evaluation was accomplished by measuring the stress transmission across the interface, tau, using an embedded single fiber fragmentation test and by using computer simulations and a finite element analysis to calculate the strain energy release rate, G, of the observed fiber-matrix debonding at the interface accompanying the first fiber fracture. The oligomer-grafted interphase exhibited improved stress transmissibility and toughness, particularly after 24 hours in boiling water. The tenacity of the tightly bound oligomers was confirmed via DRIFT, TGA and GC/MS experiments on Soxhlet extracted fibers. High resolution solid state sp{13}C and sp{29}Si CP/MAS NMR has been used to investigate the grafting mechanism, morphology and interfacial mobility of polycarbonate oligomer and bisphenol A grafted onto silica surfaces. The NMR spectra demonstrate differences between the neat and grafted PC oligomer that suggest strong bonding. A model compound, bisphenol A, was used to resolve signal overlaps due to repeat units and to verify the formation of primary bonding at the silica surface by the existence of a downfield shift of the Csb4 resonance peak and other changes in the spectrum. Proton spin-lattice relaxation times in the rotating frame offer secondary evidence of the formation of Si-O-C bonds on the silica surface. The proton spin-lattice relaxations of the

  12. An Hybrid Glass/hemp Fibers Solution Frp Pipes: Technical and Economic Advantages of Hand Lay up VS Light Rtm

    NASA Astrophysics Data System (ADS)

    Cicala, G.; Cristaldi, G.; Recca, G.; Ziegmann, G.; ElSabbagh, A.; Dickert, M.

    2008-08-01

    The aim of the present research was to investigate the replacement of glass fibers with hemp fibers for applications in the piping industry. The choice of hemp fibers was mainly related to the needs, expressed by some companies operating in this sector, for cost reduction without adversely reducing the performances of the pipes. Two processing techniques, namely hand lay up and light RTM, were evaluated. The pipe selected for the study was a curved fitting (90°) flanged at both ends. The fitting must withstand an internal pressure of 10 bar and the presence of acid aqueous solutions. The original lay-up used to build the pipe is a sequence of C-glass, glass mats and glass fabric. Commercial epoxy vinyl ester resin was used as thermoset matrix. Hemp fibers mats were selected as potential substitute of glass fibers mats because of their low cost and ready availability from different commercial sources. The data obtained from the mechanical characterization were used to define a favorable design of the pipe using hemp mats as internal layer. The proposed design for the fittings allowed for a cost reduction of about 24% and a weight saving of about 23% without any drawback in terms of the final performances. The light RTM techniques was developed on purpose for the manufacturing of the curved pipe. The comparison between hand lay up and light RTM evidenced a substantial cost reduction when light RTM was used.

  13. AN HYBRID GLASS/HEMP FIBERS SOLUTION FRP PIPES: TECHNICAL AND ECONOMIC ADVANTAGES OF HAND LAY UP VS LIGHT RTM

    SciTech Connect

    Cicala, G.; Cristaldi, G.; Recca, G.; Ziegmann, G.; ElSabbagh, A.; Dickert, M.

    2008-08-28

    The aim of the present research was to investigate the replacement of glass fibers with hemp fibers for applications in the piping industry. The choice of hemp fibers was mainly related to the needs, expressed by some companies operating in this sector, for cost reduction without adversely reducing the performances of the pipes. Two processing techniques, namely hand lay up and light RTM, were evaluated. The pipe selected for the study was a curved fitting (90 deg.) flanged at both ends. The fitting must withstand an internal pressure of 10 bar and the presence of acid aqueous solutions. The original lay-up used to build the pipe is a sequence of C-glass, glass mats and glass fabric. Commercial epoxy vinyl ester resin was used as thermoset matrix.Hemp fibers mats were selected as potential substitute of glass fibers mats because of their low cost and ready availability from different commercial sources. The data obtained from the mechanical characterization were used to define a favorable design of the pipe using hemp mats as internal layer. The proposed design for the fittings allowed for a cost reduction of about 24% and a weight saving of about 23% without any drawback in terms of the final performances.The light RTM techniques was developed on purpose for the manufacturing of the curved pipe. The comparison between hand lay up and light RTM evidenced a substantial cost reduction when light RTM was used.

  14. Resorbable composites with bioresorbable glass fibers for load-bearing applications. In vitro degradation and degradation mechanism.

    PubMed

    Lehtonen, Timo J; Tuominen, Jukka U; Hiekkanen, Elina

    2013-01-01

    An in vitro degradation study of three bioresorbable glass fiber-reinforced poly(l-lactide-co-dl-lactide) (PLDLA) composites was carried out in simulated body fluid (SBF), to simulate body conditions, and deionized water, to evaluate the nature of the degradation products. The changes in mechanical and chemical properties were systematically characterized over 52 weeks dissolution time to determine the degradation mechanism and investigate strength retention by the bioresorbable glass fiber-reinforced PLDLA composite. The degradation mechanism was found to be a combination of surface and bulk erosion and does not follow the typical core-accelerated degradation mechanism of poly(α-hydroxyacids). Strength retention by bioresorbable glass fiber-reinforced PLDLA composites can be tailored by changing the oxide composition of the glass fibers, but the structure-property relationship of the glass fibers has to be understood and controlled so that the phenomenon of ion leaching can be utilized to control the degradation rate. Therefore, these high performance composites are likely to open up several new possibilities for utilizing resorbable materials in clinical applications which could not be realized in the past. PMID:22963847

  15. Scintillating glass fiber neutron sensors: 2, Light transmission in scintillating fibers

    SciTech Connect

    Abel, K.H.; Arthur, R.J.; Bliss, M.

    1993-10-01

    The capture and transmission of light from an event through a scintillating fiber is somewhat different than in conventional optical waveguide applications. A theoretical all-ray model that depends on surface and bulk loss factors is developed for this transmission. The capture fraction can be significantly greater than that predicted on the basis of meridional rays alone and the gross loss is nonexponential for short distances (less than or of the order of one 1/e distance). The latter phenomenon occurs because high-angle and skew rays are more rapidly attenuated than meridional rays.

  16. Failure monitoring of E-glass/vinylester composites using fiber grating acoustic sensor

    NASA Astrophysics Data System (ADS)

    Azmi, A. I.; Raju; Peng, G. D.

    2013-06-01

    This paper reports an application of an optical fiber sensor in a continuous and in situ failure testing of an E-glass/vinylester top hat stiffener (THS). The sensor head was constructed from a compact phase-shifted fiber Bragg grating (PS-FBG). The narrow transmission channel of the PS-FBG is highly sensitive to small perturbation, hence suitable to be used in acoustic emission (AE) assessment technique. The progressive failure of THS was tested under transverse loading to experimentally simulate the actual loading in practice. Our experimental tests have demonstrated, in good agreement with the commercial piezoelectric sensors, that the important failures information of the THS was successfully recorded by the simple intensity-type PS-FBG sensor.

  17. 30  W fluoride glass all-fiber laser at 2.94  μm.

    PubMed

    Fortin, Vincent; Bernier, Martin; Bah, Souleymane T; Vallée, Réal

    2015-06-15

    We report the demonstration of a 2938 nm erbium-doped fluoride glass fiber laser delivering a record output power of 30.5 W in continuous wave operation. The passively cooled all-fiber laser cavity based on intracore fiber Bragg gratings has an overall laser efficiency of 16% as a function of the launched pump power at 980 nm and a single-mode output beam quality of M2<1.2. This power scaling demonstration of a fiber laser operating near the vibrational resonance of water is likely to have a significant impact on several biomedical applications. PMID:26076286

  18. Esthetic and biologic mode of reattaching incisor fracture fragment utilizing glass fiber post.

    PubMed

    Manju, M; Shanthraj, Srinivas L; Savitha, K C; Sethi, Ntasha

    2015-01-01

    Trauma to the anterior teeth affects the esthetic and psychological well-being of the patient. Advancement in the adhesive dentistry has facilitated the restoration of the coronal tooth fractures by minimally invasive procedures when the original tooth fragment is available. Reattachment of fractured fragment offers immediate treatment with improved preponderant aesthetics and restoration of function. Here, we describe a case of complicated fracture of the maxillary left immature permanent central incisor, which was treated endodontically followed by esthetic reattachment of the fractured fragment using the glass fiber post. Functional demands and esthetic considerations of the patient were fully met with this biologic mode of fragment reattachment. PMID:26283849

  19. Esthetic and biologic mode of reattaching incisor fracture fragment utilizing glass fiber post

    PubMed Central

    Manju, M.; Shanthraj, Srinivas L.; Savitha, K. C.; Sethi, Ntasha

    2015-01-01

    Trauma to the anterior teeth affects the esthetic and psychological well-being of the patient. Advancement in the adhesive dentistry has facilitated the restoration of the coronal tooth fractures by minimally invasive procedures when the original tooth fragment is available. Reattachment of fractured fragment offers immediate treatment with improved preponderant aesthetics and restoration of function. Here, we describe a case of complicated fracture of the maxillary left immature permanent central incisor, which was treated endodontically followed by esthetic reattachment of the fractured fragment using the glass fiber post. Functional demands and esthetic considerations of the patient were fully met with this biologic mode of fragment reattachment. PMID:26283849

  20. Yb-doped silica glass and photonic crystal fiber based on laser sintering technology

    NASA Astrophysics Data System (ADS)

    Zhang, Wei; Wu, Jiale; Zhou, Guiyao; Xia, Changming; Liu, Jiantao; Tian, Hongchun; Liang, Wanting; Hou, Zhiyun

    2016-03-01

    We demonstrate the fabricating method for Yb3+-doped silica glass and double-cladding large mode area photonic crystal fiber (LMA PCF) based on laser sintering technology combined with a liquid phase doping method. The doped material prepared shows the amorphous property and the hydroxyl content is approximately 40 ppm. The attenuation of the fabricated LMA PCF is 14.2 dB m-1 at 976 nm, and the lowest value is 0.25 dB m-1 at 1200 nm. The laser slope efficiency is up to 70.2%.

  1. Recommended Minimum Test Requirements and Test Methods for Assessing Durability of Random-Glass-Fiber Composites

    SciTech Connect

    Battiste, R.L.; Corum, J.M.; Ren, W.; Ruggles, M.B.

    1999-06-01

    This report provides recommended minimum test requirements are suggested test methods for establishing the durability properties and characteristics of candidate random-glass-fiber polymeric composites for automotive structural applications. The recommendations and suggestions are based on experience and results developed at Oak Ridge National Laboratory (ORNL) under a US Department of Energy Advanced Automotive Materials project entitled ''Durability of Lightweight Composite Structures,'' which is closely coordinated with the Automotive Composites Consortium. The report is intended as an aid to suppliers offering new structural composites for automotive applications and to testing organizations that are called on to characterize the composites.

  2. Evaluation of fiber-based tools for glass polishing using experimental and computational approaches.

    PubMed

    Shahinian, Hossein; Cherukuri, Harish; Mullany, Brigid

    2016-06-01

    Polymeric pad or pitch-based tools combined with loose abrasive slurries are typically used in the polishing of optical materials. In this paper, the potential of fiber-based tools to both remove material and provide high quality surface finishes on BK7 glass is explored. The potential advantage of fiber-based tools over traditional tools is their inherent compliance, which could accommodate varying workpiece surface curvatures as found in aspheres and freeforms. To evaluate the new tools, both experimental and finite element (FE) modeling approaches were taken. A FE model consisting of a single fiber engaged with the workpiece surface was used to estimate the shape and magnitude of the pressure distribution exerted by the fiber on the workpiece surface. Two different tool configurations, yielding two different Fes, predicted pressure distributions, were used to polish BK7 samples, and the material removal profiles were interferometrically measured. The resulting profiles and the predicted pressure distributions share the same v-shape. While differences in scale exist between the experimental and FE-predicted profiles, the tool generating higher material removal had the greater predicted pressure distribution, thus demonstrating the ability of the FE model to provide insights into tool design. Additional testing was conducted to determine if the tool's removal rate can be predicted by Preston's equation. Initial results indicate the equation is valid within the range of parameters tested. The surface roughness of BK7 samples processed by this tool was measured and some deterioration on the Sq value was noted; the surface roughness increased from 1.89 to 3.66 nm Sq. Over several hours of continuous use, the load applied by the fibers decays in a repeatable manner, and little wear was observed on the fibers after 5.33 h of polishing. PMID:27411180

  3. On-Line Sensor Systems for Monitoring the Cure of Coatings on Glass Optical Fibers and Assemblies

    SciTech Connect

    J.F. McClelland; R.W. Jones

    2003-10-01

    Glass fiber technology, which enables light transmission and communication over great distances, was developed in the U.S. and has evolved into a major industry in this country. Continuous innovation is required to maintain the leadership position that the U.S. enjoys in glass optical fiber technology. This project addressed a key quality assurance aspect of glass optical fiber and cable assembly production-namely, assuring full cure of the polymer coating that protects the fiber from physical damage and moisture degradation. Properly cured coatings are imperative for the cable-assembly industry because they provide protection from the environment and assure both mechanical strength and long-term performance of the cable assembly, The industry loses approximately 5% of its production due to under-cured fiber. This loss amounts to roughly $70,000,000 per year. The standard procedure in the industry is to spot check cables after production because no on-line method has been available to continuously monitor cure during either the glass-fiber drawing process, which operates at high speeds of roughly 1 kilometer per minute, or the cable-assembly process. Many kilometers of out-of-specification material can therefore be produced before tests catch the flaw. This project strove to eliminate this delay.

  4. Investigation of Fiber Waviness in a Thick Glass Composite Beam Using THz NDE

    NASA Technical Reports Server (NTRS)

    Anastasi, Robert F.

    2008-01-01

    Fiber waviness in laminated composite material is introduced during manufacture because of uneven curing, resin shrinkage, or ply buckling caused by bending the composite lay-up into its final shape prior to curing. The resulting waviness has a detrimental effect on mechanical properties, therefore this condition is important to detect and characterize. Ultrasonic characterization methods are difficult to interpret because elastic wave propagation is highly dependent on ply orientation and material stresses. By comparison, the pulsed terahertz response of the composite is shown to provide clear indications of the fiber waviness. Pulsed Terahertz NDE is an electromagnetic inspection method that operates in the frequency range between 300 GHz and 3 THz. Its propagation is influenced by refractive index variations and interfaces. This work applies pulsed Terahertz NDE to the inspection of a thick composite beam with fiber waviness. The sample is a laminated glass composite material approximately 15mm thick with a 90-degree bend. Terahertz response from the planar section, away from the bend, is indicative of a homogeneous material with no major reflections from internal plies, while the multiple reflections at the bend area correspond to the fiber waviness. Results of these measurements are presented for the planar and bend areas.

  5. Phagosomal pH and glass fiber dissolution in cultured nasal epithelial cells and alveolar macrophages: a preliminary study.

    PubMed Central

    Johnson, N F

    1994-01-01

    The dissolution rate of glass fibers has been shown to be pH sensitive using in vitro lung fluid simulant models. The current study investigated whether there is a difference in phagosomal pH (ppH) between rat alveolar macrophages (AM) and rat nasal epithelial cells (RNEC) and whether such a difference would influence the dissolution of glass fibers. The ppH was measured in cultured AM and RNEC using flow cytometric, fluorescence-emission rationing techniques with fluorescein-labeled, amorphous silica particles. Glass fiber dissolution was determined in AM and RNEC cultured for 3 weeks with fast dissolving glass fibers (GF-A) or slow dissolving ones (GF-B). The mean diameters of GF-A were 2.7 microns and of GF-B, 2.6 microns, the average length of both fibers was approximately 22 to 25 microns. Dissolution was monitored by measuring the length and diameter of intracellular fibers and estimating the volume, assuming a cylindrical morphology. The ppH of AM was 5.2 to 5.8, and the ppH of RNEC was 7.0 to 7.5. The GF-A dissolved more slowly in RNEC than in AM, and no dissolution was evident in either cell type with GF-B. The volume loss with GF-A after a 3-week culture with AM was 66% compared to 45% for cultured RNEC. These results are different from those obtained using in vitro lung fluid-simulant models where dissolution is faster at higher pH. This difference suggests that dissolution rates of glass fibers in AM should not be applied to the dissolution of fibers in epithelial cells. Images Figure 1. a Figure 1. b Figure 2. a Figure 2. b Figure 3. a Figure 3. b PMID:7882965

  6. Enhanced upconversion emission in crystallization-controllable glass-ceramic fiber containing Yb(3+)-Er(3+) codoped CaF2 nanocrystals.

    PubMed

    Peng, Wencai; Fang, Zaijin; Ma, Zhijun; Qiu, Jianrong

    2016-10-01

    Functional nanocrystal-containing materials have been a hot topic in recent years. However, few researches have focused on functional nanocrystals contained in optical glass fibers. In this research, transparent CaF2 glass-ceramic was prepared by a melt-quenching method. Greatly enhanced upconversion luminescence was observed after heat treatment. By applying a novel method called melt-in-tube, precursor fiber free of crystals was fabricated at the drawing temperature where the clad was softened while the core was melted. Glass-ceramic fiber with fiber core containing Yb(3+)-Er(3+) codoped CaF2 nanocrystals was obtained after heat treatment at a relatively low temperature. Electron probe micro-analyzer measurement shows no obvious element diffusion between the core and clad. Greatly enhanced upconversion emission was detected in the glass-ceramic fiber excited by a 980 nm laser, suggesting the developed glass-ceramic fiber is a promising material for upconversion laser. PMID:27576586

  7. The kinetics of crystallization of molten binary and ternary oxide systems and their application to the origination of high modulus glass fibers

    NASA Technical Reports Server (NTRS)

    Bacon, J. F.

    1971-01-01

    Emphasis on the consideration of glass formation on a kinetic process made it possible to think of glass compositions different from those normally employed in the manufacture of glass fibers. Approximately 450 new glass compositions were prepared and three dozen of these compositions have values for Young's modulus measured on bulk specimens greater than nineteen million pounds per square inch. Of the new glasses about a hundred could be drawn into fibers by mechanical methods at high speeds. The fiber which has a Young's modulus measured on the fiber of 18.6 million pounds per square inch and has been prepared in quantity as a monofilament (to date more than 150 million lineal feet of 0.2 to 0.4 mil fiber have been produced). This fiber has also been successfully incorporated both in epoxy and polyimide matrices. The epoxy resin composite has shown a modulus forty percent better than that achievable using the most common grade of competitive glass fiber, and twenty percent better than that obtainable with the best available grade of competitive glass fiber. Other glass fibers of even higher modulus have been developed.

  8. Thermal performance of glass fiber reinforced intumescent fire retardant coating for structural applications

    NASA Astrophysics Data System (ADS)

    Ahmad, Faiz; Ullah, Sami; Aziz, Hammad; Omar, Nor Sharifah

    2015-07-01

    The results of influence of glass fiber addition into the basic intumescent coating formulation towards the enhancement of its thermal insulation properties are presented. The intumescent coatings were formulated from expandable graphite, ammonium polyphosphate, melamine, boric acid, bisphenol A epoxy resin BE-188, polyamide amine H-2310 hardener and fiberglass (FG) of length 3.0 mm. Eight intumescent formulations were developed and the samples were tested for their fire performance by burning them at 450°C, 650°C and 850°C in the furnace for two hours. The effects of each fire test at different temperatures; low and high temperature were evaluated. Scanning Electron Microscope, X-Ray Diffraction technique and Thermo Gravimetric Analysis were conducted on the samples to study the morphology, the chemical components of char and the residual weight of the coatings. The formulation, FG08 containing 7.0 wt% glass fiber provided better results with enhanced thermal insulation properties of the coatings.

  9. Comparison of Two Techniques for Evaluation of Coronal Leakage Along of a Glass Fiber Post

    PubMed Central

    Sadighpour, L.; Rezaei, S.; Geramipanah, F.; Mohammadi, M.; Choubchian, S.

    2010-01-01

    Objective: Contradictory results have been reported over microleakage studies of restorative materials and methods. Despite the number of publications on leakage there are few evidences comparing the different microleakage evaluation methods. The purpose of the present study was to compare the clearing technique and longitudinal sectioning in the evaluation of dye penetration along a glass fiber post. Materials and Methods: Fifteen single-rooted human teeth were endontically prepared and obturated with gutta percha points and a resin based sealer (AH26). A glass fiber post (Glassix) was cemented into each post space with a dual polymerizing resin cement (Varilink II) and the composite core (Tetric Ceram) was fabricated. Specimens were immersed in Indian ink solution for 72 hours after completion of 1500 cycles of thermal cycling. Then demineralized, cleared and evaluated for the deepest length of dye penetration using a stereomicroscope. Specimens were then cut longitudinally and the length of penetration was measured again by the same instrument. The mean difference of the penetrated length was analyzed by two methods using the paired t test and an analysis of correlation (α = 0.05). Results: No significant difference was found in the mean microleakage measured by the two methods (P= 0.07). Significant correlation was found between them (P=0.0001, r= 0.9) Conclusion: The clearing technique and longitudinal sectioning showed the same results in microleakage of Glassix post and composite core within the limitation of the present study. PMID:21998786

  10. Thermal performance of glass fiber reinforced intumescent fire retardant coating for structural applications

    SciTech Connect

    Ahmad, Faiz Ullah, Sami; Aziz, Hammad Omar, Nor Sharifah

    2015-07-22

    The results of influence of glass fiber addition into the basic intumescent coating formulation towards the enhancement of its thermal insulation properties are presented. The intumescent coatings were formulated from expandable graphite, ammonium polyphosphate, melamine, boric acid, bisphenol A epoxy resin BE-188, polyamide amine H-2310 hardener and fiberglass (FG) of length 3.0 mm. Eight intumescent formulations were developed and the samples were tested for their fire performance by burning them at 450°C, 650°C and 850°C in the furnace for two hours. The effects of each fire test at different temperatures; low and high temperature were evaluated. Scanning Electron Microscope, X-Ray Diffraction technique and Thermo Gravimetric Analysis were conducted on the samples to study the morphology, the chemical components of char and the residual weight of the coatings. The formulation, FG08 containing 7.0 wt% glass fiber provided better results with enhanced thermal insulation properties of the coatings.

  11. Polypropylene/glass fiber hierarchical composites incorporating inorganic fullerene-like nanoparticles for advanced technological applications.

    PubMed

    Díez-Pascual, Ana M; Naffakh, Mohammed

    2013-10-01

    Novel isotactic polypropylene (iPP)/glass fiber (GF) laminates reinforced with inorganic fullerene-like tungsten disulfide (IF-WS2) nanoparticles as environmentally friendly fillers have been successfully fabricated by simple melt-blending and fiber impregnation in a hot-press without the addition of any compatibilizer. The influence of IF-WS2 concentration on the morphology, viscosity. and thermal and mechanical behavior of the hierarchical composites has been investigated. Results revealed an unprecedented 62 °C increase in the degradation temperature of iPP/GF upon addition of only 4.0 wt % IF-WS2. The coexistence of both micro- and nanoscale fillers resulted in synergistic effects on enhancing the stiffness, strength, crystallinity, thermal stability, glass transition (Tg) and heat distortion temperature (HDT) of the matrix. The approach used in this work is an efficient, versatile, scalable and economic strategy to improve the mechanical and thermal behavior of GF-reinforced thermoplastics with a view to extend their use in advanced technological applications. This new type of composite materials shows great potential to improve the efficiency and sustainability of many forms of transport. PMID:24015820

  12. Bioactive glass surface for fiber reinforced composite implants via surface etching by Excimer laser.

    PubMed

    Kulkova, Julia; Moritz, Niko; Huhtinen, Hannu; Mattila, Riina; Donati, Ivan; Marsich, Eleonora; Paoletti, Sergio; Vallittu, Pekka K

    2016-07-01

    Biostable fiber-reinforced composites (FRC) prepared from bisphenol-A-glycidyldimethacrylate (BisGMA)-based thermosets reinforced with E-glass fibers are promising alternatives to metallic implants due to the excellent fatigue resistance and the mechanical properties matching those of bone. Bioactive glass (BG) granules can be incorporated within the polymer matrix to improve the osteointegration of the FRC implants. However, the creation of a viable surface layer using BG granules is technically challenging. In this study, we investigated the potential of Excimer laser ablation to achieve the selective removal of the matrix to expose the surface of BG granules. A UV-vis spectroscopic study was carried out to investigate the differences in the penetration of light in the thermoset matrix and BG. Thereafter, optimal Excimer laser ablation parameters were established. The formation of a calcium phosphate (CaP) layer on the surface of the laser-ablated specimens was verified in simulated body fluid (SBF). In addition, the proliferation of MG63 cells on the surfaces of the laser-ablated specimens was investigated. For the laser-ablated specimens, the pattern of proliferation of MG63 cells was comparable to that in the positive control group (Ti6Al4V). We concluded that Excimer laser ablation has potential for the creation of a bioactive surface on FRC-implants. PMID:27134152

  13. An update on glass fiber dental restorative composites: a systematic review.

    PubMed

    Khan, Abdul Samad; Azam, Maria Tahir; Khan, Maria; Mian, Salman Aziz; Ur Rehman, Ihtesham

    2015-02-01

    Dentistry is a much developed field in the last few decades. New techniques have changed the conventional treatment methods as applications of new dental materials give better outcomes. The current century has suddenly forced on dentistry, a new paradigm regarding expected standards for state-of-the-art patient care. Within the field of restorative dentistry, the incredible advances in dental materials research have led to the current availability of esthetic adhesive restorations. The chemistry and structure of the resins and the nature of the glass fiber reinforced systems in dental composites are reviewed in relation to their influence and properties including mechanical, physical, thermal, biocompatibility, technique sensitivity, mode and rate of failure of restorations on clinical application. It is clear that a deeper understanding of the structure of the polymeric matrix and resin-based dental composite is required. As a result of ongoing research in the area of glass fiber reinforced composites and with the development and advancement of these composites, the future prospects of resin-based composite are encouraging. PMID:25492169

  14. Experimental investigation on the mechanical properties of glass fiber reinforced nylon

    NASA Astrophysics Data System (ADS)

    Nuruzzaman, D. M.; Iqbal, A. K. M. Asif; Oumer, A. N.; Ismail, N. M.; Basri, S.

    2016-02-01

    In this study, the influence of different weight percentages of glass fiber (GF) reinforcement on the mechanical properties of nylon (PA6) composite is investigated. Test specimens of pure nylon, 95% nylon + 5% GF, 90% nylon + 10% GF, 85% nylon + 15% GF and 80% nylon + 20% GF are prepared using an injection molding machine. In the experiments, tensile tests and impact tests are carried out. The obtained results reveal that mechanical properties of the nylon composites are significantly influenced by the weight percentage of glass fiber. From the tensile test results, it is observed that pure nylon has the lowest elastic modulus and yield strength whereas 80% nylon + 20% GF composite shows the highest elastic modulus and yield strength. Moreover, pure nylon shows the lowest tensile strength while 80% nylon + 20% GF shows significantly improved tensile strength. Results show that elongation at break is remarkably high for pure nylon whereas it is very low for 80% nylon + 20% GF. Izod impact test results reveal that, 85% nylon + 15% GF composite has the highest impact strength or toughness whereas 95% nylon + 5% GF composite shows the lowest impact strength. Furthermore, 80% nylon + 20% GF composite shows somewhat less impact strength or toughness than 85% nylon + 15% GF composite.

  15. Two-color mid-infrared thermometer using a hollow glass optical fiber

    SciTech Connect

    Small, W., IV.; Celliers, P.M.; Da Silva, L.D.; Matthews, D.L.

    1997-06-30

    A non-invasive two-color infrared thermometer has been developed for low-temperature biomedical applications. Mid-infrared radiation from the target is collected via a single 700 {mu}m-bore hollow glass optical fiber, simultaneously split into two paths and modulated by a gold-coated reflective optical chopper, and focused onto two thermoelectrically-cooled HgCdZnTe photoconductors (bandpasses of 2- 6 {mu}m and 2-12 {mu}m, respectively) by gold-coated spherical mirrors. The small numerical aperture of the hollow glass fiber provides high spatial resolution (is less than 1 mm), and the hollow bore eliminates reflective losses. The modulated detector signals are recovered using lock-in amplification, permitting measurement of small low-temperature signal buried in the background. A computer algorithm calculates the true temperature and emissivity of the target in real time based on a previous blackbody (emissivity equal to 1) calibration, taking into account reflection of the ambient radiation field from the target surface.

  16. Infrared imaging spectrometry by the use of bundled chalcogenide glass fibers and a PtSi CCD camera

    NASA Astrophysics Data System (ADS)

    Saito, Mitsunori; Kikuchi, Katsuhiro; Tanaka, Chinari; Sone, Hiroshi; Morimoto, Shozo; Yamashita, Toshiharu T.; Nishii, Junji

    1999-10-01

    A coherent fiber bundle for infrared image transmission was prepared by arranging 8400 chalcogenide (AsS) glass fibers. The fiber bundle, 1 m in length, is transmissive in the infrared spectral region of 1 - 6 micrometer. A remote spectroscopic imaging system was constructed with the fiber bundle and an infrared PtSi CCD camera. The system was used for the real-time observation (frame time: 1/60 s) of gas distribution. Infrared light from a SiC heater was delivered to a gas cell through a chalcogenide fiber, and transmitted light was observed through the fiber bundle. A band-pass filter was used for the selection of gas species. A He-Ne laser of 3.4 micrometer wavelength was also used for the observation of hydrocarbon gases. Gases bursting from a nozzle were observed successfully by a remote imaging system.

  17. Athermal distributed Brillouin sensors utilizing all-glass optical fibers fabricated from rare earth garnets: LuAG

    NASA Astrophysics Data System (ADS)

    Dragic, P. D.; Pamato, M. G.; Iordache, V.; Bass, J. D.; Kucera, C. J.; Jones, M.; Hawkins, T. W.; Ballato, J.

    2016-01-01

    An all-glass optical fiber derived from single-crystal LuAG is investigated for its potential use in athermal Brillouin distributed strain sensors. Such sensor systems are comprised of fiber whose Brillouin frequency shift is independent of temperature, but not independent of strain. Bulk Brillouin spectroscopy measurements on the precursor LuAG crystal are performed to gain insight into the crystal-to-glass transition. Results suggest that both the mass density and acoustic velocity are reduced relative to the crystal phase, in common with the other rare earth aluminosilicates. Advantages of the LuAG derived fiber over other rare earth garnet-derived fibers for the sensing application are a stronger strain response and larger Brilloun gain with narrower Brillouin spectral width.

  18. Case Report: Analytical Electron Microscopy of Lung Granulomas Associated with Exposure to Coating Materials Carried by Glass Wool Fibers

    PubMed Central

    Ferreira, Angela S.; Moreira, Valéria B.; Castro, Marcos César S.; Soares, Porfírio J.; Algranti, Eduardo; Andrade, Leonardo R.

    2010-01-01

    Context Man-made vitreous fibers (MMVFs) are noncrystalline inorganic fibrous material used for thermal and acoustical insulation (e.g., rock wool, glass wool, glass microfibers, and refractory ceramic fibers). Neither epidemiologic studies of human exposure nor animal studies have shown a noticeable hazardous effect of glass wools on health. However, MMVFs have been anecdotally associated with granulomatous lung disease in several case reports. Case presentation Here, we describe the case of a patient with multiple bilateral nodular opacities who was exposed to glass wool fibers and coating materials for 7 years. Bronchoalveolar lavage fluid revealed an increased total cell count (predominantly macrophages) with numerous cytoplasmic particles. Lung biopsy showed peribronchiolar infiltration of lymphoid cells and many foreign-body–type granulomas. Alveolar macrophages had numerous round and elongated platelike particles inside the cytoplasm. X-ray microanalysis of these particles detected mainly oxygen/aluminum/silicon and oxygen/magnesium/silicon, compatible with kaolinite and talc, respectively. No elemental evidence for glass fibers was found in lung biopsy. Discussion The contribution of analytical electron microscopy applied in the lung biopsy was imperative to confirm the diagnosis of pneumoconiosis associated with a complex occupational exposure that included both MMVFs and coating materials. Relevance to clinical or professional practice This case study points out the possible participation of other components (coating materials), beyond MMVFs, in the etiology of pneumoconiosis. PMID:20123612

  19. Interfacial studies of refractory glass-ceramic matrix/advanced SiC fiber-reinforced composites. Annual report, 1 Feb 91-1 Feb 92

    SciTech Connect

    Brennan, J.J.

    1992-04-30

    The main objective of this program is to characterize the chemistry and structure of new advanced small diameter silicon based fibers and how these factors influence the nature of the fiber/matrix interface in refractory glass-ceramic matrix composites. It is the nature of this interface that then determines to a great degree the composite thermal, environmental, and mechanical properties. The fibers under investigation during the second year of this program included the new experimental polymer derived crystalline SiC fibers from Dow Corning Corp., the Si-N-C-O 'Black' fibers from Textron Specialty Materials, as well as the new low oxygen radiation cured Nicalon SiC type fibers from Nippon Carbon Co. Since the availability of all of these fibers was extremely limited, emphasis was placed on the mechanical, chemical, and microstructural characterization of the fibers through tensile testing, SEM of fiber fracture characteristics, scanning Auger depth profiling of fiber surfaces, and TEM of fiber thin sections, as well as their fracture behavior, bonding characteristics, and interfacial compatibility with various glass-ceramic matrix materials. Results of these analyses are discussed. Crystalline SiC fibers, Textron 'Black' fibers, low oxygen Nicalon fibers, SiC fiber/glass-ceramic matrix interfaces, TEM fiber analyses.

  20. Bioactive Glass Fiber Reinforced Starch-Polycaprolactone Composite for Bone Applications

    SciTech Connect

    Jukola, H.; Nikkola, L.; Tukiainen, M.; Kellomaeki, M.; Ashammakhi, N.; Gomes, M. E.; Reis, R. L.; Chiellini, F.; Chiellini, E.

    2008-02-15

    For bone regeneration and repair, combinations of different materials are often needed. Biodegradable polymers are often combined with osteoconductive materials, such as bioactive glass (BaG), which can also improve the mechanical properties of the composite. The aim of this study was to develop and characterize BaG fiber-reinforced starch-poly-{epsilon}-caprolactone (SPCL) composite. Sheets of SPCL (30/70 wt%) were produced using single-screw extrusion. They were then cut and compression molded in layers with BaG fibers to form composite structures of different combinations. Thermal, mechanical, and degradation properties of the composites were studied. The actual amount of BaG in the composites was determined using combustion tests. A strong endothermic peak indicating melting at about 56 deg. C was observed by differential scanning calorimetry (DSC) analysis. Thermal gravimetry analysis (TGA) showed that thermal decomposition of SPCL started at 325 deg. C with the decomposition of starch and continued at 400 deg. C with the degradation of polycaprolactone (PCL). Initial mechanical properties of the reinforced composites were at least 50% better than the properties of the non-reinforced composites. However, the mechanical properties of the composites after two weeks of hydrolysis were comparable to those of the non-reinforced samples. During the six weeks' hydrolysis the mass of the composites had decreased only by about 5%. The amount of glass in the composites remained the same for the six-week period of hydrolysis. In conclusion, it is possible to enhance the initial mechanical properties of SPCL by reinforcing it with BaG fibers. However, the mechanical properties of the composites are only sufficient for use as filler material and they need to be further improved to allow long-lasting bone applications.

  1. Bioactive Glass Fiber Reinforced Starch-Polycaprolactone Composite for Bone Applications

    NASA Astrophysics Data System (ADS)

    Jukola, H.; Nikkola, L.; Gomes, M. E.; Chiellini, F.; Tukiainen, M.; Kellomäki, M.; Chiellini, E.; Reis, R. L.; Ashammakhi, N.

    2008-02-01

    For bone regeneration and repair, combinations of different materials are often needed. Biodegradable polymers are often combined with osteoconductive materials, such as bioactive glass (BaG), which can also improve the mechanical properties of the composite. The aim of this study was to develop and characterize BaG fiber-reinforced starch-poly-ɛ-caprolactone (SPCL) composite. Sheets of SPCL (30/70 wt%) were produced using single-screw extrusion. They were then cut and compression molded in layers with BaG fibers to form composite structures of different combinations. Thermal, mechanical, and degradation properties of the composites were studied. The actual amount of BaG in the composites was determined using combustion tests. A strong endothermic peak indicating melting at about 56 °C was observed by differential scanning calorimetry (DSC) analysis. Thermal gravimetry analysis (TGA) showed that thermal decomposition of SPCL started at 325 °C with the decomposition of starch and continued at 400 °C with the degradation of polycaprolactone (PCL). Initial mechanical properties of the reinforced composites were at least 50% better than the properties of the non-reinforced composites. However, the mechanical properties of the composites after two weeks of hydrolysis were comparable to those of the non-reinforced samples. During the six weeks' hydrolysis the mass of the composites had decreased only by about 5%. The amount of glass in the composites remained the same for the six-week period of hydrolysis. In conclusion, it is possible to enhance the initial mechanical properties of SPCL by reinforcing it with BaG fibers. However, the mechanical properties of the composites are only sufficient for use as filler material and they need to be further improved to allow long-lasting bone applications.

  2. Reinforcement of Dental Methacrylate with Glass Fiber after Heated Silane Application

    PubMed Central

    Fonseca, Rodrigo Borges; de Paula, Marcella Silva; Favarão, Isabella Negro; Kasuya, Amanda Vessoni Barbosa; de Almeida, Letícia Nunes; Mendes, Gustavo Adolfo Martins; Carlo, Hugo Lemes

    2014-01-01

    This study evaluated the influence of silane heat treatment and glass fiber fabrication type, industrially treated (I) or pure (P), on flexural and compressive strength of methacrylate resin bars (BISGMA/TEGDMA, 50/50%). Six groups (n = 10) were created: I-sil: I/silanated; P-sil: P-silanated; I-sil/heat: I/silanated heated to 100°; P-sil/heat: P/silanated heated to 100°; (I: I/not silanated; and P: P/not silanated. Specimens were prepared for flexural strength (10 × 2 × 1 mm) and for compressive strength 9.5 × 5.5 × 3 mm) and tested at 0.5 mm/min. Statistical analysis demonstrated the following for flexural strength (P < 0.05): I-sil: 155.89 ± 45.27BC; P-sil: 155.89 ± 45.27BC; I-sil/heat: 130.20 ± 22.11C; P-sil/heat: 169.86 ± 50.29AB; I: 131.87 ± 15.86C. For compressive strength, the following are demonstrated: I-sil: 1367.25 ± 188.77ab; P-sil: 867.61 ± 102.76d; I-sil/heat: 1162.98 ± 222.07c; P-sil/heat: 1499.35 ± 339.06a; and I: 1245.78 ± 211.16bc. Due to the impossibility of incorporating the stipulated amount of fiber, P group was excluded. Glass fiber treatment with heated silane enhanced flexural and compressive strength of a reinforced dental methacrylate. PMID:24967361

  3. [Failure conditions of glass filament yarns: a contribution to the valuation of carcinogenic potentials of fiber fragments].

    PubMed

    Oser, M; Ramseyer, C; Mayer, J; Wintermantel, E

    1998-09-01

    Failure of glass filament yarns results in the formation of many fragments. Through inhalation, these particles can intrude into the human body. If the fragments are sufficiently bioresistant and have a fiber dust geometry, according to the MAK-values (6), i.e. if they are longer than 5 microns and thinner than 3 microns and show an aspect ratio greater than 3, they have a carcinogenic potential. Since the glass filaments show a diameter greater than 3 microns, no fiber dust particles will be formed if transversal fiber failure occurs without crack-branching. In the present study the geometric distribution of fragments after failure of glass filament yarns under combined stress was investigated in order to estimate the carcinogenic potential of the fragments. The knot tension test was shown to be a suitable method for this investigation. A defined fraction of the total amount of fragments were analysed with scanning electron microscopy (SEM) by measuring their length and diameter. To investigate whether the analysed particles are fragments of the glass filament yarns, chemical analysis was performed with energy dispersive X-ray analysis (EDX). Morphologically, two different fragment types were observed: a) Fragments with their entire filament cross-section which were formed by transversal fiber fraction. b) Smaller fragments which were formed through crack-branching. These smaller fragments were observed to adhere on the bigger fragments due to high surface forces. During each knot tension test, 5-60 fragments per filament were formed. However, the fraction of fiber dust particles was very low and showed a maximum of 1.5%. Only in one of the four tested yarn types (high temperature yarn HT 75) the formation of fiber dust particles was observed. The other yarns showed fragments with dimensions close to fiber dust geometry. Therefore, it cannot be excluded that some fragments with fiber dust geometry may have been formed during mechanical testing. Fragment

  4. Cytotoxicity, oxidative stress and genotoxicity induced by glass fibers on human alveolar epithelial cell line A549.

    PubMed

    Rapisarda, Venerando; Loreto, Carla; Ledda, Caterina; Musumeci, Giuseppe; Bracci, Massimo; Santarelli, Lory; Renis, Marcella; Ferrante, Margherita; Cardile, Venera

    2015-04-01

    Man-made vitreous fibers have been widely used as insulation material as asbestos substitutes; however their morphology and composition raises concerns. In 1988 the International Agency for Research on Cancer classified fiberglass, rock wool, slag wool, and ceramic fibers as Group 2B, i.e. possibly carcinogenic to humans. In 2002 it reassigned fiberglass, rock and slag wool, and continuous glass filaments to Group 3, not classifiable as carcinogenic to humans. The aim of this study was to verify the cytotoxic and genotoxic effects and oxidative stress production induced by in vitro exposure of human alveolar epithelial cells A549 to glass fibers with a predominant diameter <3 μm (97%) and length >5 μm (93%). A549 cells were incubated with 5, 50, or 100 μg/ml (2.1, 21, and 42 μg/cm(2), respectively) of glass fibers for 72 h. Cytotoxicity and DNA damage were tested by the MTT and the Comet assay, respectively. Oxidative stress was determined by measuring inducible nitric oxide synthase (iNOS) expression by Western blotting, production of nitric oxide (NO) with Griess reagent, and concentration of reactive oxygen species by fluorescent quantitative analysis with 2',7'-dichlorofluorescein-diacetate (DCFH-DA). The results showed that glass fiber exposure significantly reduced cell viability and increased DNA damage and oxidative stress production in a concentration-dependent manner, demonstrating that glass fibers exert cytotoxic and genotoxic effects related to increased oxidative stress on the human alveolar cell line A549. PMID:25620604

  5. Comment on the reported fiber attenuations in the visible regime in 'Fabrication of glass photonic crystal fibers with a die-cast process'

    SciTech Connect

    Feng Xian; Loh, Wei H.; Richardson, David J

    2008-10-01

    We comment on the recent paper by Zhou et al. [Appl. Opt.45, 4433 (2006)APOPAI0003-693510.1364/AO.45.004433], in which transmission losses of 0.2-0.3 dB/m were claimed across the wavelength range 420-900 nm in a high-index (nd=1.80518 at 587.6 nm) SF6 glass-based photonic crystal fiber fabricated by novel die-cast technique. If confirmed, these losses are at least 1 order of magnitude lower than previous reported losses of SF6 photonic crystal fibers from other fabrication approaches. Here we present a statistic survey on the relationship between the refractive index and the bulk material attenuation, based on a large number of commercial Schott optical glasses with the nd ranging between 1.40 and 2.05. It shows that the loss of a high-index (nd=1.80) glass optical fiber should be at the levels of 10-50 dB/m at 420 nm and 1-10 dB/m at 500 nm, respectively. Moreover, the material attenuation of such a high-index glass fiber should intrinsically show a large decay, from 10-50 dB/m at 420 nm to the level of 1 dB/m at 700 nm, which arises from the tail on the UV absorption edge of the high-index glass extending to the visible region. Therefore, we conclude that: (1) the low loss of 0.2-0.3 dB/m reported in the cited paper is abnormally one or two magnitudes lower than the material attenuation that a high-index (nd=1.80) glass optical fiber should have in the range between 420 and 500 nm and that (2) the flat loss curve between 420 and 700 nm in the cited paper deviates greatly from the intrinsic behavior of a high-index (nd=1.80) glass fiber.

  6. Effect of Glass Fiber Incorporation on Flexural Properties of Experimental Composites

    PubMed Central

    Fonseca, Rodrigo Borges; Marques, Aline Silva; Bernades, Karina de Oliveira; Carlo, Hugo Lemes; Naves, Lucas Zago

    2014-01-01

    This study evaluated the effect of fiber addiction in flexural properties of 30 wt% silica filled BisGMA resin (FR) or unfilled Bis-GMA (UR). Ten groups were created (N = 10) varying the resin (FR or UR) and quantity of glass fibers (wt%: 0, 10, 15, 20, and 30). Samples (10 × 2 × 1 mm) were submitted to flexural strength test following SEM examination. Data were analyzed by two-way ANOVA, Tukey, and Student t-test (α = 0.05). Results for flexural strength (MPa) were FR-groups: 0% (442.7 ± 140.6)C, 10% (772.8 ± 446.3)ABC, 15% (854.7 ± 297.3)AB, 20% (863.4 ± 418.0)A, 30% (459.5 ± 140.5)BC; UR-groups: 0% (187.7 ± 120.3)B, 10% (795.4 ± 688.1)B, 15% (1999.9 ± 1258.6)A, 20% (1911.5 ± 596.8)A, and 30% (2090.6 ± 656.7)A, and for flexural modulus (GPa) FR-groups: 0% (2065.63 ± 882.15)B, 10% (4479.06 ± 3019.82)AB, 15% (5694.89 ± 2790.3)A, 20% (6042.11 ± 3392.13)A, and 30% (2495.67 ± 1345.86)B; UR-groups: 0% (1090.08 ± 708.81)C, 10% (7032.13 ± 7864.53)BC, 15% (19331.57 ± 16759.12)AB, 20% (15726.03 ± 8035.09)AB, and 30% (29364.37 ± 13928.96)A. Fiber addiction in BisGMA resin increases flexural properties, and the interaction between resin and fibers seems better in the absence of inorganic fillers increasing flexural properties. PMID:25136595

  7. A 2 μm continuous wave and passively Q-switched fiber laser in thulium-doped germanate glass fibers

    NASA Astrophysics Data System (ADS)

    Fan, Xiaokang; Kuan, Peiwen; Li, Kefeng; Zhang, Lei; Li, Wentao; Hu, Lili

    2014-08-01

    In this study, we designed and fabricated a Tm3+-doped germanate glass fiber by using a rod-in-tube technique. The fiber has a core diameter of ~13.5 μm with a cladding of 125 μm. The Tm3+ doping concentration reached ~13 500 ppm, and the propagation loss of the fiber was less than 0.03 dB cm - 1 at 1310 nm. Pumping with a 1590 nm fiber laser constructed in-house, a 44.7 mW continuous-wave fiber laser at 1940 nm was achieved in a 22 cm-long germanate fiber, with a slope efficiency of 26%. The passively Q-switched pulse output was first demonstrated by using a carbon nanotube saturable absorber in the germanate fiber. The germanate fiber laser generates approximately 1.5 μs pulses with a maximum pulse energy of 110 nJ, and the repetition rate varies from 15 to 84 kHz, depending on pump power.

  8. Low loss, wide transparency, robust tellurite glass fibers for mid-IR (2 - 5 μm) applications

    NASA Astrophysics Data System (ADS)

    Rhonehouse, Dan L.; Zong, Jie; Nguyen, Dan; Thapa, Rajesh; Wiersma, Kort; Smith, Chris; Chavez-Pirson, Arturo

    2013-10-01

    Mid Infrared (MIR) fiber optics has gained a great deal of interest over the past several decades. Applications range from passive transport to fiber lasers and nonlinear applications. These fibers have found use in a wide array of fields such as sensing, military countermeasures, scientific instrumentation, medical instrumentation, and in research laboratories. As with all fiber development there is a continual urge to seek better performance characteristics including transparency over a wide wavelength range, corrosion resistance, high power handling and low loss. We report on development of tellurite glass fibers displaying exceptionally high performance for various applications including wide band, low loss passive transport for mid IR, high efficiency, wide wavelength range and high power supercontinuum generation from visible to MIR wavelengths >4.5um, and active doping in fibers for use in laser cooling. High performance in each of these areas of interest has been brought about by development of a stable glass formulation and advanced processing techniques to remove impurities ions, entrapped hydroxyl, and scatter centers which allow fibers to be made with exceptionally low losses ~0.2dB/m.

  9. Chemical Vapor Deposited SiC (SCS-0) Fiber-Reinforced Strontium Aluminosilicate Glass-Ceramic Composites

    NASA Technical Reports Server (NTRS)

    Bansal, Narottam P.

    1997-01-01

    Unidirectional SrO Al2O3 2SiO2 glass-ceramic matrix composites reinforced with uncoated Chemical Vapor Deposited (CVD) SiC (SCS-0) fibers have been fabricated by hot-pressing under appropriate conditions using the glass-ceramic approach. Almost fully dense composites having a fiber volume fraction of 0.24 have been obtained. Monoclinic celsian, SrAl2Si2O8, was the only crystalline phase observed in the matrix by x-ray diffraction. No chemical reaction was observed between the fiber and the matrix after high temperature processing. In three-point flexure, the composite exhibited a first matrix cracking stress of approx. 231 +/- 20 MPa and an ultimate strength of 265 +/- 17 MPa. Examination of fracture surfaces revealed limited short length fiber pull-out. From fiber push-out, the fiber/matrix interfacial debonding and frictional strengths were evaluated to be approx. 17.5 +/- 2.7 MPa and 11.3 +/- 1.6 MPa, respectively. Some fibers were strongly bonded to the matrix and could not be pushed out. The micromechanical models were not useful in predicting values of the first matrix cracking stress as well as the ultimate strength of the composites.

  10. Experiments on fiber-break progression and local load transfer in a model graphite/glass/epoxy microcomposite

    SciTech Connect

    Gulino, R.

    1988-01-01

    A review of the experimental literature on the probabilistic/micromechanical theory of failure of continuous unidirectional composites indicates that crack propagation in the transverse and longitudinal direction depends primarily on the load transfer between the fiber and matrix, and on the strength of the fibers. Currently, neither the matrix constitutive behavior nor the fiber strength at small gauge lengths, {approx} 0.5 mm, are known with sufficient detail to evaluate micromechanical models. This investigation focused on the independent and concurrent determination of the graphite/epoxy load transfer and the graphite fiber strength distribution. The method consisted of the fabrication and observed tensile loading of a three-fiber, microcomposite tape containing a closely spaced planar array of a glass/graphite/glass fiber in an epoxy matrix. The load transfer was modeled using shear lag assumptions, where the epoxy shear behavior was best described by an elastic, plastic, and debond zone. The Weibull parameters for the strength of filaments within a sample were estimated by an approximate model for the number of breaks as a function of strain. The model assumed the flaws were distributed according to a Poisson process such that the resulting distribution for the strength of a single fiber had Weibull form.

  11. The effect of pressure changes during simulated diving on the pull out strength of glass fiber posts

    PubMed Central

    Gulve, Meenal Nitin; Gulve, Nitin Dilip

    2013-01-01

    Background: Scuba diving is one of the fastest growing sports in the world. The objective of this study was to evaluate the effect of pressure variations to which divers are exposed on the pull out strength of glass fiber post luted with different cements. Materials and Methods: In this in vitro study, 120 extracted, single-rooted lower premolars were endodontically treated. They were randomly divided into six groups and restored using the glass fiber post (Ivoclar Vivadent AG) and the following luting agents: Zinc phosphate, conventional glass ionomer, resin reinforced glass ionomer, resin cement with etch-and-rinse adhesive, resin cement with self-etching adhesive, and self-adhesive resin cement. Each group was randomly divided into two equal subgroups, one as a control, and the other to be used experimentally. After 7 days of storage, experimental groups were pressure cycled. The force required to dislodge each post was recorded in Newton (N) on Universal testing machine (Star Testing System) at a crosshead speed of 1 mm/min. Data were statistically analyzed using the ANOVA and Student's t-test (P < 0.001). Results: The pull out strength of posts cemented with zinc phosphate and conventional glass ionomer in pressure cycle group was significantly less than their control group. Although, no significant difference was found between pressure cycle and control group using resin reinforced glass ionomer cement and resin cements. Conclusion: Dentist should consider using resin reinforced glass ionomer or resin cement, for the cementation of glass fiber post, for the patients such as divers, who are likely to be exposed to pressure cycling. PMID:24379861

  12. Micromechanics of ambient temperature cyclic fatigue loading in a composite of CAS glass ceramic reinforced with Nicalon fibers

    SciTech Connect

    Rousseau, C.Q.; Davidson, D.L.; Campbell, J.B. )

    1994-04-01

    The behavior of a Nicalon fiber reinforced glass ceramic composite cyclicly loaded has been evaluated at ambient temperature using high-resolution micromechanical test methods. On this basis, the events leading to fracture have been found to be similar to those accompanying fracture in unidirectional tension tests. Matrix strains were determined locally at the point of matrix fracture. Crack opening displacements (CODs) were measured as a function of loading cycles, and fiber strains were determined, in some cases. It is concluded that debonding of fibers begins at the point of matrix cracking and rapidly increases. Most of the cyclic lifetime of the material is spent with fibers debonded over large distances (fractions of a millimeter); these fibers are pulled out of the matrix on each loading cycle. Final debond length, as determined by fractography, is a function of the number of cycles to fracture, and of the applied stress level. 23 refs.

  13. Reactive molten core fabrication of glass-clad Se(0.8)Te(0.2) semiconductor core optical fibers.

    PubMed

    Tang, Guowu; Qian, Qi; Wen, Xin; Chen, Xiaodong; Liu, Wangwang; Sun, Min; Yang, Zhongmin

    2015-09-01

    Phosphate glass-clad optical fibers comprising amorphous Se(0.8)Te(0.2) semiconductor core were fabricated by a reactive molten core approach. The Se(0.8)Te(0.2) crystals were precipitated in core region by a postdrawing annealing process, which were confirmed by X-ray diffraction, micro-Raman spectra, electron probe X-ray micro-analyzer, and transmission electron microscope measurement results. A two-cm-long crystalline Se(0.8)Te(0.2) semiconductor core optical fiber, electrically contacted to external circuitry through the fiber end facets, exhibits a two-orders-of-magnitude change in conductivity between dark and illuminated states. The great discrepancy in light and dark conductivity suggests that such crystalline Se(0.8)Te(0.2) semiconductor core optical fibers have promising applications in optical switch and photoconductivity of optical fiber array. PMID:26368460

  14. Light-weight sandwich panel honeycomb core with hybrid carbon-glass fiber composite skin for electric vehicle application

    NASA Astrophysics Data System (ADS)

    Cahyono, Sukmaji Indro; Widodo, Angit; Anwar, Miftahul; Diharjo, Kuncoro; Triyono, Teguh; Hapid, A.; Kaleg, S.

    2016-03-01

    The carbon fiber reinforced plastic (CFRP) composite is relative high cost material in current manufacturing process of electric vehicle body structure. Sandwich panels consisting polypropylene (PP) honeycomb core with hybrid carbon-glass fiber composite skin were investigated. The aim of present paper was evaluate the flexural properties and bending rigidity of various volume fraction carbon-glass fiber composite skins with the honeycomb core. The flexural properties and cost of panels were compared to the reported values of solid hybrid Carbon/Glass FRP used for the frame body structure of electric vehicle. The finite element model of represented sandwich panel was established to characterize the flexural properties of material using homogenization technique. Finally, simplified model was employed to crashworthiness analysis for engine hood of the body electric vehicle structure. The good cost-electiveness of honeycomb core with hybrid carbon-glass fiber skin has the potential to be used as a light-weight alternative material in body electric vehicle fabricated.

  15. Strength of anisotropic wood and synthetic materials. [plywood, laminated wood plastics, glass fiber reinforced plastics, polymeric film, and natural wood

    NASA Technical Reports Server (NTRS)

    Ashkenazi, Y. K.

    1981-01-01

    The possibility of using general formulas for determining the strength of different anisotropic materials is considered, and theoretical formulas are applied and confirmed by results of tests on various nonmetallic materials. Data are cited on the strength of wood, plywood, laminated wood plastics, fiber glass-reinforced plastics and directed polymer films.

  16. Novel Application of Glass Fibers Recovered From Waste Printed Circuit Boards as Sound and Thermal Insulation Material

    NASA Astrophysics Data System (ADS)

    Sun, Zhixing; Shen, Zhigang; Ma, Shulin; Zhang, Xiaojing

    2013-10-01

    The aim of this study is to investigate the feasibility of using glass fibers, a recycled material from waste printed circuit boards (WPCB), as sound absorption and thermal insulation material. Glass fibers were obtained through a fluidized-bed recycling process. Acoustic properties of the recovered glass fibers (RGF) were measured and compared with some commercial sound absorbing materials, such as expanded perlite (EP), expanded vermiculite (EV), and commercial glass fiber. Results show that RGF have good sound absorption ability over the whole tested frequency range (100-6400 Hz). The average sound absorption coefficient of RGF is 0.86, which is prior to those of EP (0.81) and EV (0.73). Noise reduction coefficient analysis indicates that the absorption ability of RGF can meet the requirement of II rating for sound absorbing material according to national standard. The thermal insulation results show that RGF has a fair low thermal conductivity (0.046 W/m K), which is comparable to those of some insulation materials (i.e., EV, EP, and rock wool). Besides, an empirical dependence of thermal conductivity on material temperature was determined for RGF. All the results showed that the reuse of RGF for sound and thermal insulation material provided a promising way for recycling WPCB and obtaining high beneficial products.

  17. NEUTRON ACTIVATION ANALYSIS FOR SIMULTANEOUS DETERMINATION OF TRACE ELEMENTS IN AMBIENT AIR COLLECTED ON GLASS-FIBER FILTERS

    EPA Science Inventory

    Arsenic with 25 other elements are simultaneously determined in ambient air samples collected on glass-fiber filter composites at 250 United States sites. The instrumental neutron activation analysis (NAA) technique combined with the power of a dedicated mini-computer resulted in...

  18. Accessory lateral discoid meniscus.

    PubMed

    Saygi, Baransel; Yildirim, Yakup; Senturk, Salih; Sezgin Ramadan, Saime; Gundes, Hakan

    2006-12-01

    The lateral meniscus tends to have more developmental variation than the medial counterpart. This is a report of an accessory discoid layer of lateral meniscus. All arthroscopic, magnetic resonance imaging and histopathological views are presented. PMID:16710729

  19. Retention of mechanical properties and cytocompatibility of a phosphate-based glass fiber/polylactic acid composite.

    PubMed

    Ahmed, I; Cronin, P S; Abou Neel, E A; Parsons, A J; Knowles, J C; Rudd, C D

    2009-04-01

    Polymers prepared from polylactic acid (PLA) have found a multitude of uses as medical devices. The main advantage of having a material that degrades is so that an implant would not necessitate a second surgical event for removal. In addition, the biodegradation may offer other advantages. In this study, fibers produced from a quaternary phosphate-based glass (PBG) in the system 50P(2)O(5)-40CaO-5Na(2)O-5Fe(2)O(3) (nontreated and heat-treated) were used to reinforce the biodegradable polymer, PLA. Fiber properties were investigated, along with the mechanical and degradation properties and cytocompatibility of the composites produced. Retention of mechanical properties overtime was also evaluated. The mean fiber strength for the phosphate glass fibers was 456 MPa with a modulus value of 51.5 GPa. Weibull analysis revealed a shape and scale parameter value of 3.37 and 508, respectively. The flexural strength of the composites matched that for cortical bone; however, the modulus values were lower than those required for cortical bone. After 6 weeks of degradation in deionized water, 50% of the strength values obtained was maintained. The composite degradation properties revealed a 14% mass loss for the nontreated and a 10% mass loss for the heat-treated fiber composites. It was also seen that by heat-treating the fibers, chemical and physical degradation occurred much slower. The pH profiles also revealed that nontreated fibers degraded quicker, thus correlating well with the degradation profiles. The in vitro cell culture experiments revealed both PLA (alone) and the heat-treated fiber composites maintained higher cell viability as compared to the nontreated fiber composites. This was attributed to the slower degradation release profiles of the heat-treated composites as compared to the nontreated fiber composites. SEM analyses revealed a porous structure after degradation, and it is clear that there are possibilities here to tailor the distribution of porosity

  20. Modeling the flexural fatigue behavior of glass-fiber-reinforced thermoplastic matrices

    NASA Astrophysics Data System (ADS)

    D'Amore, Alberto; Grassia, Luigi; Verde, Pasquale

    2013-02-01

    A two-parameter model explicitly accounting for the cyclic as well as the mean stress was proposed and tested on the basis of static and fatigue data obtained in four-point bending on a random continuous glass-fiber-reinforced polypropylene. The model is based on residual strength degradation and captures the effect of stress ratio (i.e. the ratio between the minimal and the maximal stress). The experimental data were in excellent agreement with the theoretical predictions, indicating that a fatigue characterization can be achieved with a minimum of experimental tests. Further, the reasonable agreement between the static strength data and the theoretical predictions highlighted the potential and reliability of the model in view of its statistical implementation

  1. PNNL/Euratom glass fiber-optic, spent-fuel profile measurement system

    SciTech Connect

    Bowyer, S.M.; Smart, J.E.; Hansen, R.R.

    1999-07-01

    Discussions between Euratom and Pacific Northwest National Laboratory (PNNL) revealed a need for a neutron detection system that could measure the neutron profile down the entire length of a CASTOR in one measurement. The CASTORS (dry storage casks for spent fuel and vitrified wastes) are {approximately}6 m high and 2 x 2 m square in cross section. Neutron profiles of the CASTORS are desirable for both content identification and verification. Profile measurements have traditionally been done with {sup 3}He-based detectors {approximately}1 m high that scan the length of a CASTOR as they are lifted by a crane. Geometric reproducibility errors plague this type of measurement; hence, the ability to simultaneously measure the neutron profile over the entire length of the CASTOR became highly desirable. Use of the PNNL-developed neutron-sensitive glass fibers in the construction of a 6-m-high detector was proposed, and design and construction of the detector began.

  2. Flexural strengthening of Reinforced Concrete (RC) Beams Retrofitted with Corrugated Glass Fiber Reinforced Polymer (GFRP) Laminates

    NASA Astrophysics Data System (ADS)

    Aravind, N.; Samanta, Amiya K.; Roy, Dilip Kr. Singha; Thanikal, Joseph V.

    2015-01-01

    Strengthening the structural members of old buildings using advanced materials is a contemporary research in the field of repairs and rehabilitation. Many researchers used plain Glass Fiber Reinforced Polymer (GFRP) sheets for strengthening Reinforced Concrete (RC) beams. In this research work, rectangular corrugated GFRP laminates were used for strengthening RC beams to achieve higher flexural strength and load carrying capacity. Type and dimensions of corrugated profile were selected based on preliminary study using ANSYS software. A total of twenty one beams were tested to study the load carrying capacity of control specimens and beams strengthened with plain sheets and corrugated laminates using epoxy resin. This paper presents the experimental and theoretical study on flexural strengthening of Reinforced Concrete (RC) beams using corrugated GFRP laminates and the results are compared. Mathematical models were developed based on the experimental data and then the models were validated.

  3. Non-destructive evaluation of delamination growth in glass fiber composites using optical coherence tomography

    NASA Astrophysics Data System (ADS)

    Liu, Ping; Groves, Roger M.; Benedictus, Rinze

    2014-03-01

    Based on low coherence interferometry, a robust optical coherence tomography (OCT) system has been built. The system was used to monitor the growth of a delamination between the middle layers of a glass fiber composite under a static loading. Firstly specimens of the material used for the spar webs in wind turbines were prepared with an interlaminar crack from free edges. Then they were statically loaded by a customized tensile test stage to extend the delamination length and simultaneously scanned by the OCT system. To process the acquired data, an optimized signal processing algorithm was developed. The cross-sectional images clearly show the microstructure and the crack within the specimen. The 3D crack profiles show the application of OCT to determine the evolution of the crack structure inside the composite material during the propagation of the delamination, for the first time to the best of our knowledge.

  4. Application of glass-fiber reinforced plastic (GRP) mud-mats for Daria-A platform

    SciTech Connect

    Bertorelli, D.; Spessa, A.

    1994-12-31

    A review of the experience gained with glass-fiber reinforced plastic (GRP) mud-mat materials used for the Garibaldi-C jacket, in the Adriatic sea, has shown that this solution can result in substantial cost savings. Therefore, Agip has investigated a further use of GRP mud-mats for the Daria-A platform as a means of reducing the lifting weight of the jacket and, moreover, to negate the requirement for additional buoyancy tanks during the free flotation and upending phases. Two possible solutions, the ``pultrusion`` and the ``lamination`` techniques, have been investigated to fabricate sandwich panels for the mud-mats. In this paper these two technologies are discussed with respect to their application to the construction and they are compared on a performance and cost basis.

  5. Supersonic Panel Flutter Test Results for Flat Fiber-Glass Sandwich Panels with Foamed Cores

    NASA Technical Reports Server (NTRS)

    Tuovila, W. J.; Presnell, John G., Jr.

    1961-01-01

    Flutter tests have been made on flat panels having a 1/4 inch-thick plastic-foam core covered with thin fiber-glass laminates. The testing was done in the Langley Unitary Plan wind tunnel at Mach numbers from 1.76 t o 2.87. The flutter boundary for these panels was found to be near the flutter boundary of thin metal panels when compared on the basis of an equivalent panel stiffness. The results also demonstrated that the depth of the cavity behind the panel has a pronounced influence on flutter. Changing the cavity depth from 1 1/2 inches to 1/2 inch reduced the dynamic pressure at start of flutter by 40 percent. No flutter was obtained when the spacers on the back of the panel were against the bottom of the cavity.

  6. Two-color infrared thermometer for low-temperature measurement using a hollow glass optical fiber

    SciTech Connect

    Small, W.

    1997-02-28

    In the thermometer, radiation from a target is collected via a single 700 {mu}m-bore hollow glass optical fiber coated with a metallic/dielectric layer on the inner surface, simultaneously split into two paths and modulated by a Au-coated reflective chopper, and focused onto two thermoelectrically cooled mid-infrared HgCdZnTe photoconductors by 128.8 mm-radius Au-coated spherical mirrors. The photoconductors have spectral bandpasses of 2-6 {mu}m and 2.12 {mu}m, respectively. The modulated detector signals are recovered using lock- in amplification. The two signals are calibrated using a blackbody (emissivity=1) of known temperature, and exponential fits are applied to the two resulting voltage vs temperature curves. Using the two calibration equations, a computer algorithm calculates the temperature and emissivity of a target in real time, taking into account reflection of the background radiation field from the target surface.

  7. Mechanical properties of as-cast and heat-treated ZA-27 alloy/short glass fiber composites

    SciTech Connect

    Sharma, S.C.; Girish, B.M.; Satish, B.M.; Kamath, R.

    1998-02-01

    This paper reports on the mechanical properties of as-cast and heat-treated ZA-27 alloy composites reinforced with glass fibers from 1 to 5 wt%. The composites were fabricated using the Compocasting method, in which short glass fibers were introduced into the vortex created in the molten alloy through an impeller rotated at 500 rpm. The molten mass was thoroughly stirred and poured into permanent molds and squeezed under pressure. The specimens were heat treated at 320 C for 1, 2, 3, and 4 h. The tests on the as-cast composites revealed that as the glass content in the composites was increased, the ultimate tensile strength (UTS), compressive strength, and hardness of the composite increased, while the ductility and impact strength were decreased. Heat treatment was found to improve significantly the ductility, compressive strength, and impact strength, while the hardness and UTS were reduced. This paper discusses the behavior of these composites.

  8. The development of a potassium-sulfide glass fiber cell and studies on impurities in alkali metal-sulfur cells

    NASA Technical Reports Server (NTRS)

    Tsang, F. Y.

    1977-01-01

    Potassium sulfur rechargeable cells, having as the electrolyte the thin walls of hollow glass fibers made from permeable glass, were developed. The cells had short lives, probably due to the construction materials and impurities in the potassium. The effect of the impurities in the analogous NA-S system was studied. Calcium, potassium, and NaOH/oxide impurities caused increased resistance or corrosion of the glass fibers. For long lived cell operation, the Na must contain less than 1 ppm Ca and less than a few ppm of hydroxide/oxide. Up to 150 ppm K can be tolerated. After purification of the Na anolyte, cell lifetimes in excess of 1000 deep charge-discharge cycles or over 8 months on continuous cycling at 10-30 percent depth of discharge were obtained.

  9. Investigation of micro laser drilling on thin glass fibers by femtosecond laser

    NASA Astrophysics Data System (ADS)

    Suzuki, Teruhiko; Tokita, Daisaku; Watanabe, Kazuhiro

    2010-09-01

    High-precision processing and microfabrication has been realized with the use of a femtosecond laser which with an ultrahigh-peak power and an ultrashort pulse. Such processing of glass materials has never been accomplished through conventional methods, and has been realized only through nonlinear optical phenomena using femtosecond lasers. Moreover, photonic devices such as optical waveguides, photonic crystals and 3D-memory devices have been developed. In our laboratory, precise holes with high aspect ratios are created in micro-scale glass materials for the purpose of developing novel optical devices. This research is conducted by using a fundamental wave (800 nm) and a second harmonic generation (SHG: 400 nm) of a Ti-Sapphire laser with various irradiation conditions at each wavelength in order to find the optimal processing parameters. In addition, optical silica fibers have been used target objects. First, a calibration experiment was carried out by fixing the repetition frequency and the number of pulses and changing the irradiation fluence. Next, another calibration experiment was carried out by fixing the irradiation frequency and the number of pulses and changing the repetition frequency. Last, an experiment on changing the number of pulses was conducted by using the fundamental wave. In this paper, the results of these experiments and the processing parameters required for the development of novel optical devices are described.

  10. Ultra-bandwidth polarization splitter based on soft glass dual-core photonic crystal fiber

    NASA Astrophysics Data System (ADS)

    Fan, Zhenkai; Li, Shu-Guang; Li, Jianshe; Wei, Zhiyi; Tian, Wenlong

    2015-08-01

    A novel ultra-bandwidth polarization splitter based on soft glass dual-core photonic crystal fiber (DC-PCF) is designed in this paper, which is analyzed through the finite element method (FEM). The coupling characteristics of the designed DC-PCF can be enhanced by a high refractive index As2S3 core. Numerical results show the ultra-bandwidths of the x- and y-polarization modes can reach to 86 nm and 60 nm as the extinction ratios better than -20 dB and -30 dB at the vicinity of the wavelength of 1.31 μm. The length of the designed soft glass DC-PCF is 52.29 mm and the extinction ratios of the x- and y-polarization modes are -85.57 dB and -56.81 dB at the wavelength of 1.31 μm, respectively. In addition, the designed splitter has a tolerance of ±10 nm in its all structure parameters, which make the design not sensitive to the perturbation during the fabrication process.

  11. Continuous carbon and glass fiber reinforced polypropylene: Optimization of the compression molding process

    SciTech Connect

    Denault, J.; Guillemenet, J.

    1996-12-31

    The objective of this work was to optimize the processing conditions of polypropylene/carbon, PP/C, and polypropylene/glass, PP/G, composites. Investigation of the effects of molding parameters such as molding temperature and residence time and cooling rate on the tensile performance of PP/C and PP/G was undertaken. It is well known that the mechanical performance of composite based on thermoplastic matrix such as polypropylene is closely related to crystalline morphology which is dependent on the thermal history. Since the compression molding process involves kinetic behavior of systems undergoing phase transformations under non-isothermal conditions, the crystallization behavior of PP matrix in the presence of carbon and glass fibers was investigated under non-isothermal conditions. The effects of processing temperature, residence time and cooling rate on the crystallization temperature, degree of crystallinity, crystallization rate and kinetics of crystallization were analyzed. The tensile behavior of the {+-}45{degrees} laminate of PP/C and PP/G and their interfacial properties were evaluated as a function of molding parameters. The variation in the tensile strength of the {+-}45{degrees} laminates as a function of molding temperature was found to show three distinct regions: the tensile strength first increases with molding temperature, attains a plateau region, and finally decreases at high molding temperature. DSC analysis done in order to simulate phase transformation under non-isothermal conditions also revealed similar behavior suggesting a close relationship between mechanical performance and matrix properties.

  12. Fiber optic monitoring of carbamate pesticides using porous glass with covalently bound chlorophenol red.

    PubMed

    Xavier, M P; Vallejo, B; Marazuela, M D; Moreno-Bondi, M C; Baldini, F; Falai, A

    2000-02-01

    An optical fiber biosensor for the determination of the pesticides propoxur (Baygon) and carbaryl, two of the most commonly used carbamate insecticides in vegetable crops, is described. A pH indicator, chlorophenol red, is used as optical transducer of the inhibition of the enzyme acetylcholinesterase by the analytes. The biorecognition element is covalently immobilized onto controlled pore glass beads (CPG) and packed in a thermostatized bioreactor connected to a flow-through cell that contains CPG-immobilized chlorophenol red placed at the common end of a bifurcated fiber optic bundle. In the presence of a constant acetylcholine concentration, the colour of the pH sensitive layer changes and the measured reflectance signal can be related to the carbamate concentration in the sample solution. The performance of the biosensor has been optimized using a flow injection system. The linear dynamic range for the determination of carbaryl and propoxur spans from 0.8 to 3.0 mg l(-1) and from 0.03 to 0.50 mg l(-1), respectively. The detection limit (3 s) of the biosensor for propoxur (0.4 ng) is lower than that measured for carbaryl (25 ng). Reproducibility, stability and interference studies of the optical device are reported. The biosensor has been applied to the determination of propoxur in spiked vegetables (onion and lettuce) using ultrasound extraction, achieving recovery values between 93 and 95% for onion samples at the different concentration levels assayed. PMID:10722147

  13. Micromechanical modeling of short glass-fiber reinforced thermoplastics-Isotropic damage of pseudograins

    SciTech Connect

    Kammoun, S.; Brassart, L.; Doghri, I.; Delannay, L.; Robert, G.

    2011-05-04

    A micromechanical damage modeling approach is presented to predict the overall elasto-plastic behavior and damage evolution in short fiber reinforced composite materials. The practical use of the approach is for injection molded thermoplastic parts reinforced with short glass fibers. The modeling is proceeded as follows. The representative volume element is decomposed into a set of pseudograins, the damage of which affects progressively the overall stiffness and strength up to total failure. Each pseudograin is a two-phase composite with aligned inclusions having same aspect ratio. A two-step mean-field homogenization procedure is adopted. In the first step, the pseudograins are homogenized individually according to the Mori-Tanaka scheme. The second step consists in a self-consistent homogenization of homogenized pseudograins. An isotropic damage model is applied at the pseudograin level. The model is implemented as a UMAT in the finite element code ABAQUS. Model is shown to reproduce the strength and the anisotropy (Lankford coefficient) during uniaxial tensile tests on samples cut under different directions relative to the injection flow direction.

  14. Irradiation conditions for fiber laser bonding of HAp-glass ceramics with bovine cortical bone.

    PubMed

    Tadano, Shigeru; Yamada, Satoshi; Kanaoka, Masaru

    2014-01-01

    Orthopedic implants are widely used to repair bones and to replace articulating joint surfaces. It is important to develop an instantaneous technique for the direct bonding of bone and implant materials. The aim of this study was to develop a technique for the laser bonding of bone with an implant material like ceramics. Ceramic specimens (10 mm diameter and 1 mm thickness) were sintered with hydroxyapatite and MgO-Al2O3-SiO2 glass powders mixed in 40:60 wt% proportions. A small hole was bored at the center of a ceramic specimen. The ceramic specimen was positioned onto a bovine bone specimen and a 5 mm diameter area of the ceramic specimen was irradiated using a fiber laser beam (1070-1080 nm wavelength). As a result, the bone and the ceramic specimens bonded strongly under the irradiation conditions of a 400 W laser power and a 1.0 s exposure time. The maximum shear strength was 5.3 ± 2.3 N. A bonding substance that penetrated deeply into the bone specimen was generated around the hole in the ceramic specimen. On using the fiber laser, the ceramic specimen instantaneously bonded to the bone specimen. Further, the irradiation conditions required for the bonding were investigated. PMID:24840194

  15. Effect of temperature on the dynamic characteristics of the glass-carbon fiber hybrid composites

    NASA Astrophysics Data System (ADS)

    Hidayat, Yon Afif; Susilo, Didik Djoko; Raharjo, Wijang W.

    2016-03-01

    This study aimed to investigate the effect of temperature on the dynamic characteristics of hybrid composites. Hybrid composites consisting of unsaturated polyester resin and glass fiber reinforced with carbon fiber. The volume fraction used in this study was 0.4. The hybrid composite was made using hand lay-up technique. The dynamic characteristics were obtained through vibration testing. The testing was conducted according to ASTM E756. The variables studied were composite without heating, heating at 100 °C, 200 °C and 280 °C. The experiments were done in three mounting configurations, i.e. upright, downward and horizontal configurations. The natural frequency and damping ratio was determined using half-power bandwidth method. The results showed that heating of composite structure affects the natural frequency and damping ratio of the hybrid composite. Heating until 100 °C will increase the natural frequency of the hybrid composite and decrease the damping ratio, but heating at the temperature above 100 °C will decrease the natural frequency and will damage the hybrid composite structure. The composite mounting configurations do not give significant effect to natural frequency and damping ratio of the hybrid composites.

  16. Chemical and physical degradation of glass fiber reinforced cross-linked polyester immersed in hot water

    SciTech Connect

    Hamada, H.; Maekawa, Z.I.; Ikuta, N.; Kiyosumi, K.; Tanimoto, T.; Morii, T.

    1994-12-31

    This study deals with chemical and physical degradation behavior of randomly oriented E-glass fiber continuous strand mat reinforced cross-linked polyester immersed in hot water at 80 and 95 C. The specimens were immersed in hot water for 3, 10, 30, 100, 300, 1000, 3000 and 4000h. Weight change measurement, three-point bending and infrared measurement were performed for the specimens after the immersion. Changes of the weight gain indicated the Fickian diffusion at early immersion time, and after that, it indicated the non-Fickian diffusion with a gradual progress of debonding between fiber and matrix. This degradation of the interface caused a remarkable increase of the weight loss, which was never observed in neat resin. The bending modulus decreased with increase of the weight gain at early immersion time, however, it kept constant at longer immersion time both at 80 C and at 95 C. The constant modulus level at 80C was higher than that at 95 C. At longer immersion time at 80 C, the modulus decreased again to the same level at 95C. The results of infrared measurement suggested the difference of degradation mechanism between early immersion time and longer immersion time. At early immersion time, the resin changed physically by swelling and extraction of polymer with water penetration. Such differences of degradation affected the reduction of modulus. Moreover, the effect of the debonding at the interface on the modulus was discussed by the finite element analysis by introducing the damage mechanics.

  17. Multichannel transition emissions of Dy{sup 3+} in fiber-adaptive germanium tellurite glasses

    SciTech Connect

    Li, Y. H.; Chen, B. J.; Lin, H.; Pun, E. Y. B.

    2013-03-28

    Multichannel transition visible and near-infrared (NIR) fluorescences have been captured in Dy{sup 3+}-doped fiber-adaptive Na{sub 2}O-ZnO-PbO-GeO{sub 2}-TeO{sub 2} glasses. The maximum stimulated emission cross-sections {sigma}{sub em-max} were derived to be 0.33 Multiplication-Sign 10{sup -21}, 3.66 Multiplication-Sign 10{sup -21}, and 0.67 Multiplication-Sign 10{sup -21} cm{sup 2} for conventional visible emissions assigned to {sup 4}F{sub 9/2}{yields}{sup 6}H{sub J} (J = 15/2, 13/2, and 11/2) transitions, respectively. Infrequent multi-peak NIR emissions were recorded in the spectral range of 900-1500 nm, among which the values of {sigma}{sub em-max} were solved to be 1.05 Multiplication-Sign 10{sup -22} and 1.56 Multiplication-Sign 10{sup -22} cm{sup 2} for {approx}1.02 and {approx}1.18 {mu}m emission bands. Internal quantum efficiency for the {sup 4}F{sub 9/2} level and external quantum yield for visible emissions of Dy{sup 3+} were determined to be 88.44% and 12.38%, severally. Effective multichannel radiative emissions reveal a potential in developing fiber-lighting sources, tunable lasers, and NIR optical amplifiers.

  18. Thermal expansion coefficients of a 30% glass fiber filled PEEK pyrotechnic charge holder

    SciTech Connect

    Donnelly, M.W.; Walters, R.R.; Miller, G.D.

    1985-01-01

    Pyrotechnic actuators use hollow cylindrical ceramic or plastic charge holders to electrically isolate the pyrotechnic charge from the actuator case. In a newly developed actuator, 30% glass fiber filled polyetheretherketone (PEEK) was selected as the charge holder material both for its strength and its forming properties. Because the actuators are exposed to significant temperature variations during storage and flight, a determination of the coefficient of thermal expansion, ..cap alpha.., of the charge holders was required to assure success in this, the first electroexplosive device application of PEEK. Of special interest in this project were the questions of whether ..cap alpha.. depends on the direction (with respect to flow in the mold) or on injection pressure. From the test results, the conclusions are: (1) ..cap alpha.. does depend on direction. Its value in the thickness direction is approximately twice that in either the height or circumferential direction. This is probably because the wall thickness, 0.015'', is less than the average fiber length, 0.100'', and the PEEK is, therefore, not acting as a composite in the t direction. (2) Varying the injection pressure over the range of this study has no detectable effect on ..cap alpha... This charge holder is molded into an Inconel actuator case with ..cap alpha.. = 11.4 ..mu..m/m.C. This relatively close match of ..cap alpha..'s between adjacent materials has resulted in no dimensional problems during manufacturing and environmental testing. 1 fig., 1 tab.

  19. Effects of Fiber Content on Mechanical Properties of CVD SiC Fiber-Reinforced Strontium Aluminosilicate Glass-Ceramic Composites

    NASA Technical Reports Server (NTRS)

    Bansal, Narottam P.

    1996-01-01

    Unidirectional CVD SiC(f)(SCS-6) fiber-reinforced strontium aluminosilicate (SAS) glass-ceramic matrix composites containing various volume fractions, approximately 16 to 40 volume %, of fibers were fabricated by hot pressing at 1400 C for 2 h under 27.6 MPa. Monoclinic celsian, SrAl2Si2O8, was the only crystalline phase formed, with complete absence of the undesired hexacelsian phase, in the matrix. Room temperature mechanical properties were measured in 3-point flexure. The matrix microcracking stress and the ultimate strength increased with increase in fiber volume fraction, reached maximum values for V(sub f) approximately equal to 0.35, and degraded at higher fiber loadings. This degradation in mechanical properties is related to the change in failure mode, from tensile at lower V(sub f) to interlaminar shear at higher fiber contents. The extent of fiber loading did not have noticeable effect on either fiber-matrix debonding stress, or frictional sliding stress at the interface. The applicability of micromechanical models in predicting the mechanical properties of the composites was also examined. The currently available theoretical models do not appear to be useful in predicting the values of the first matrix cracking stress, and the ultimate strength of the SCS-6/SAS composites.

  20. Characterization of porous glass fiber-reinforced composite (FRC) implant structures: porosity and mechanical properties.

    PubMed

    Ylä-Soininmäki, Anne; Moritz, Niko; Lassila, Lippo V J; Peltola, Matti; Aro, Hannu T; Vallittu, Pekka K

    2013-12-01

    The aim of this study was to characterize the microstructure and mechanical properties of porous fiber-reinforced composites (FRC). Implants made of the FRC structures are intended for cranial applications. The FRC specimens were prepared by impregnating E-glass fiber sheet with non-resorbable bifunctional bis-phenyl glycidyl dimethacrylate and triethylene glycol dimethacrylate resin matrix. Four groups of porous FRC specimens were prepared with a different amount of resin matrix. Control group contained specimens of fibers, which were bound together with sizing only. Microstructure of the specimens was analyzed using a micro computed tomography (micro-CT) based method. Mechanical properties of the specimens were measured with a tensile test. The amount of resin matrix in the specimens had an effect on the microstructure. Total porosity was 59.5 % (median) in the group with the lowest resin content and 11.2 % (median) in the group with the highest resin content. In control group, total porosity was 94.2 % (median). Correlations with resin content were obtained for all micro-CT based parameters except TbPf. The tensile strength of the composites was 21.3 MPa (median) in the group with the highest resin content and 43.4 MPa (median) in the group with the highest resin content. The tensile strength in control group was 18.9 MPa (median). There were strong correlations between the tensile strength of the specimens and most of the micro-CT based parameters. This experiment suggests that porous FRC structures may have the potential for use in implants for cranial bone reconstructions, provided further relevant in vitro and in vivo tests are performed. PMID:23929214

  1. The influence of fiber/matrix interface on the mechanical behavior of Nicalon SiC fiber reinforced glass-ceramic composites

    SciTech Connect

    Liu, Y.M.; Mitchell, T.E.; Wadley, H.N.G.

    1996-11-01

    Mechanical properties of unidirectional Nicalon SiC fiber reinforced Ca aluminosilicate (CAS/SiC) and Mg aluminosilicate (MAS/SiC) glass-ceramic composites were investigated by tensile testing and nondestructive laser-ultrasound technique. The Ba-stuffed MAS was either undoped or doped with 5% borosilicate glass. Degradation of elastic stiffness constant C{sub 11} in transverse direction due to interface damage was monitored in situ by measuring the laser- generated ultrasound wave velocity. The three composite materials show different characteristics of macroscopic deformation behavior, which is correlated strongly to interface degradation. A stronger reduction trend of the elastic constant C{sub 11} is associated with a larger degree of inelastic deformation. The fracture surfaces also reveal the close relation between fiber pullout length and interfacial characteristics. Interfaces of these composites were studied by TEM; their influence on inhibiting and deflecting matrix cracks is discussed.

  2. 3D FEA of cemented glass fiber and cast posts with various dental cements in a maxillary central incisor.

    PubMed

    Madfa, Ahmed A; Al-Hamzi, Mohsen A; Al-Sanabani, Fadhel A; Al-Qudaimi, Nasr H; Yue, Xiao-Guang

    2015-01-01

    This study aimed to analyse and compare the stability of two dental posts cemented with four different luting agents by examining their shear stress transfer through the FEM. Eight three-dimensional finite element models of a maxillary central incisor restored with glass fiber and Ni-Cr alloy cast dental posts. Each dental post was luted with zinc phosphate, Panavia resin, super bond C&B resin and glass ionomer materials. Finite element models were constructed and oblique loading of 100 N was applied. The distribution of shear stress was investigated at posts and cement/dentine interfaces using ABAQUS/CAE software. The peak shear stress for glass fiber post models minimized approximately three to four times of those for Ni-Cr alloy cast post models. There was negligible difference in peak of shear stress when various cements were compared, irrespective of post materials. The shear stress had same trend for all cement materials. This study found that the glass fiber dental post reduced the shear stress concentration at interfacial of post and cement/dentine compared to Ni-Cr alloy cast dental post. PMID:26543733

  3. Epoxy/Glass Fiber Laminated Composites Integrated with Amino Functionalized ZrO2 for Advanced Structural Applications.

    PubMed

    Halder, Sudipta; Ahemad, Soyeb; Das, Subhankar; Wang, Jialai

    2016-01-27

    This work demonstrates the successful silanization of ZrO2 nanoparticles (ZN) and their incorporation in glass fiber/epoxy composites. Microscopic investigation under transmission electron microscope elucidates antiaggregation and size enhancement of silanized ZrO2 nanoparticles (SZNs). FTIR spectroscopy has been used to demonstrate the chemical nature of the SZNs prepared. EDX results reveal the presence of Si onto SZNs. Incorporation of SZNs shows a strong influence on tensile and flexural properties of hybrid multiscale glass fiber composite (SZGFRP) compared to that of the neat epoxy glass fiber composite (GFRP). A significant variation of tensile strength, stiffness, and toughness of ∼27%, 62%, and 110% is observed with respect to GFRP. Strength and modulus under bending are also enhanced to ∼22% and ∼38%, respectively. Failure mechanisms obtained from macroscopic and microscopic investigation demonstrate reduced interfacial delamination for SZGFRP. Additionally, increased roughness of the fiber surface in SZGFRP laminates produces better interfacial bonding arising from SZN incorporation in laminates. This symptomatic behavior exposes the espousal of organically modified ZrO2 to enhance the interfacial bonding for their use in next generation hybrid laminates. PMID:26714570

  4. Measurement of thermal conductivity of PbTe nanocrystal coated glass fibers by the 3ω method.

    PubMed

    Finefrock, Scott W; Wang, Yan; Ferguson, John B; Ward, James V; Fang, Haiyu; Pfluger, Jonathan E; Dudis, Douglas S; Ruan, Xiulin; Wu, Yue

    2013-11-13

    Fiber-based thermoelectric materials can conform to curved surfaces to form energy harvesting devices for waste heat recovery. Here we investigate the thermal conductivity in the axial direction of glass fibers coated with lead telluride (PbTe) nanocrystals using the self-heated 3ω method particularly at low frequency. While prior 3ω measurements on wire-like structures have only been demonstrated for high thermal conductivity materials, the present work demonstrates the suitability of the 3ω method for PbTe nanocrystal coated glass fibers where the low thermal conductivity and high aspect ratio result in a significant thermal radiation effect. We simulate the experiment using a finite-difference method that corrects the thermal radiation effect and extract the thermal conductivity of glass fibers coated by PbTe nanocrystals. The simulation method for radiation correction is shown to be generally much more accurate than analytical methods. We explore the effect of nanocrystal volume fraction on thermal conductivity and obtain results in the range of 0.50-0.93 W/mK near room temperature. PMID:24147725

  5. Toward a mid-infrared femtosecond laser system with suspended-core tungstate-tellurite glass fibers.

    PubMed

    Anashkina, E A; Andrianov, A V; Dorofeev, V V; Kim, A V

    2016-06-10

    A simple design of a fiber laser system for generating high-quality pulses with a duration of order 100 fs with ultrabroad wavelength tunability in the 2-5 μm range is discussed. This design incorporates conventional fs near-IR lasers and specially developed tungstate-tellurite fibers with two zero-dispersion wavelengths (ZDW) and relies on nonlinear wavelength conversion via either soliton self-frequency shift (SSFS) or red-shifted dispersive wave (DW) generation. The fiber parameters needed for such optical conversion have been scanned numerically and showed a possibility of SSFS beyond 4 μm and of DW generation beyond 5 μm. We have also studied and prepared tungstate-tellurite glasses and preforms that are highly stable against crystallization, exhibit extremely low level of hydroxyl groups absorption, and from which the suspended-core two-ZDW fibers can be manufactured. PMID:27409007

  6. Glass fiber dissolution in simulated lung fluid and measures needed to improve consistency and correspondence to in vivo dissolution.

    PubMed Central

    Mattson, S M

    1994-01-01

    The dissolution of a range of glass fibers including commercial glass and mineral wools has been studied using a modification of Gamble's solution in a flow system at pH 7.4 and 37 degrees C. Dissolution has been followed by weight loss, effluent analysis, and morphology change of fibers and bulk glass. Flow per glass surface area can strongly affect both dissolution rate and morphology due to the effect of the dissolution process on the fluid. Effluent pH is shown to be a guide for choice of optimum flow/area conditions. These conditions provide measurable concentrations of dissolved glass in the effluent while maintaining their concentrations below the point at which they significantly affect the dissolution process. SiO2 and Al2O3 vary widely in the extent to which they are involved in the leaching process, which removes alkalis, alkaline earths, and B2O3. This makes analysis of a single component in the effluent unsuitable as a means of comparing the dissolution rates of a wide range of compositions. PMID:7882963

  7. Accessory oral cavity

    PubMed Central

    Gnaneswaran, Manica Ramamoorthy; Varadarajan, Usha; Srinivasan, Ramesh; Kamatchi, Sangeetha

    2012-01-01

    This is a rare case report of a patient around 11 years with the complaint of extra mouth who reported to the hospital for removal of that extra mouth. On examination there was accessory oral cavity with small upper and lower lips, seven teeth and saliva was drooling out. Under general anesthesia crevicular incision from 32 to 43 was put and labial gingiva with alveolar mucosa was reflected completely and bone exposed to lower border of mandible. There were seven teeth resembling lower permanent anterior teeth in the accessory mouth, which was excised with the accessory lips. 41 extracted and osteotomy carried out extending the incision from the extracted site and osteotomy carried out. Dermoid cyst both below and above the mylohyoid muscle and rudimentary tongue found and excised and the specimen sent for histopathological examination. The wound was closed and uneventful healing noted to the satisfaction of the patient. This is a rare and interesting case which has been documented. PMID:23833508

  8. Effect of Zn addition on non-resonant third-order optical nonlinearity of the Cu-doped germano-silicate optical glass fiber.

    PubMed

    Ju, Seongmin; Watekar, Pramod R; Jeong, Seongmook; Kim, Youngwoong; Han, Won-Taek

    2012-01-01

    Cu/Zn-codoped germano-silicate optical glass fiber was manufactured by using the modified chemical vapor deposition (MCVD) process and solution doping process. To investigate the reduction effect of Zn addition on Cu metal formation in the core of the Cu/Zn-codoped germano-silicate optical glass fiber, the optical absorption property and the non-resonant third-order optical nonlinearity were measured. Absorption peaks at 435 nm and 469 nm in the Cu/Zn-codoped germano-silicate optical glass fiber were contributed to Cu metal particles and ZnO semiconductor particles, respectively. The effective non-resonant optical nonlinearity, gamma, of the Cu/Zn-codoped germano-silicate optical glass fiber was measured to be 1.5097 W(-1) x km(-1) by using the continuous-wave self-phase modulation method. The gamma of the Cu/Zn-codoped germano-silicate optical glass fiber was about four times larger than that of the reference germano-silicate optical glass fiber without any dopants. The increase of the effective non-resonant optical nonlinearity, gamma, of the Cu/Zn-codoped germano-silicate optical glass fiber, can be attributed to the enhanced nonlinear polarization due to incorporated ZnO semiconductor particles and Cu metal ions in the glass network. The Cu/Zn-codoped germano-silicate optical glass fiber showed high nonlinearity and low transmission loss at the optical communication wavelength, which makes it suitable for high-speed-high-capacity optical communication systems. PMID:22524031

  9. Clinical evaluation of carbon fiber reinforced carbon endodontic post, glass fiber reinforced post with cast post and core: A one year comparative clinical study

    PubMed Central

    Preethi, GA; Kala, M

    2008-01-01

    Aim: Restoring endodontically treated teeth is one of the major treatments provided by the dental practitioner. Selection and proper use of restorative materials continues to be a source of frustration for many clinicians. There is controversy surrounding the most suitable choice of restorative material and the placement method that will result in the highest probability of successful treatment. This clinical study compares two different varieties of fiber posts and one cast post and core in terms of mobility of crown margin under finger pressure, recurrent caries detected at the crown margin, fracture of the restoration, fracture of the root and periapical and periodontal pathology requiring crown removal over the period of 12months as evaluated by clinical and radiographical examination. Materials and Methods: 30 root canal treated, single rooted maxillary anterior teeth of 25 patients in the age range of 18–60 years where a post retained crown was indicated were selected for the study between January 2007 and August 2007; and prepared in a standard clinical manner. It was divided into 3 groups of 10 teeth in each group. After post space preparation, the Carbon fiber and Glass fiber reinforced posts were cemented with Scotch bond multipurpose plus bonding agent and RelyX adhesive resin cement in the first and second groups respectively. The Cast post and cores were cemented with Zinc Phosphate cement in the third group. Following post- cementation, the preparation was further refined and a rubber base impression was taken for metal-ceramic crowns which was cemented with Zinc Phosphate cement. A baseline periapical radiograph was taken once each crown was cemented. All patients were evaluated after one week (baseline), 3 months, 6 months and one year for following characteristics mobility of crown margin under finger pressure, recurrent caries detected at the crown margin, fracture of the restoration, fracture of the root and periapical and periodontal pathology

  10. Strain measurement in a concrete beam by use of the Brillouin-scattering-based distributed fiber sensor with single-mode fibers embedded in glass fiber reinforced polymer rods and bonded to steel reinforcing bars.

    PubMed

    Zeng, Xiaodong; Bao, Xiaoyi; Chhoa, Chia Yee; Bremner, Theodore W; Brown, Anthony W; DeMerchant, Michael D; Ferrier, Graham; Kalamkarov, Alexander L; Georgiades, Anastasis V

    2002-08-20

    The strain measurement of a 1.65-m reinforced concrete beam by use of a distributed fiber strain sensor with a 50-cm spatial resolution and 5-cm readout resolution is reported. The strain-measurement accuracy is +/-15 microepsilon (microm/m) according to the system calibration in the laboratory environment with non-uniform-distributed strain and +/-5 microepsilon with uniform strain distribution. The strain distribution has been measured for one-point and two-point loading patterns for optical fibers embedded in pultruded glass fiber reinforced polymer (GFRP) rods and those bonded to steel reinforcing bars. In the one-point loading case, the strain deviations are +/-7 and +/-15 microepsilon for fibers embedded in the GFRP rods and fibers bonded to steel reinforcing bars, respectively, whereas the strain deviation is +/-20 microepsilon for the two-point loading case. PMID:12206221

  11. The effect of glass and polyethylene fiber reinforcement on flexural strength of provisional restorative resins: an in vitro study.

    PubMed

    Natarajan, Parthasarathy; Thulasingam, C

    2013-12-01

    The aim is to evaluate and compare the flexural strength of different provisional restorative materials reinforced with glass and polyethylene fibers. A total of 90 samples were prepared and divided into three groups based on the type of fiber reinforcement, unidirectional S-glass (Splint-It) and ultra-molecular weight polyethylene (Ribbond). Unreinforced samples served as control group. Again each group was subdivided into three subgroups based on type of provisional restorative resins, heats cure polymethyl methacrylate, self-cure poly methyl methacrylate and self-cure bis-acryl composite. Samples were loaded in a universal testing machine until fracture occurs. The mean flexural strengths (MPa) were subjected to the one-way ANOVA, followed by the Tukey-HSD test at a significance level of 0.001. The result shows all the fiber reinforced samples possessed greater strength than the control samples. In control samples, the heat cure poly methyl methacrylate resin (72.74 ± 2.28 MPa) had the greatest flexural strength, followed by self-cure bis-acryl composite (67.05 ± 2.35 MPa) and self-cure poly methyl methacrylate resin (52.88 ± 1.90 MPa). In both heat and self-cure poly methyl methacrylate resin, the polyethylene fiber reinforcement (96.00 ± 2.63 MPa, 86.17 ± 1.92 MPa) provides the greatest strength than glass fiber reinforcement (92.68 ± 1.58 MPa, 76.40 ± 2.11 MPa). In self-cure bis-acryl composite, the glass fiber (105.95 ± 3.07 MPa) shows better reinforcement than polyethylene fiber (99.41 ± 1.74 MPa).The fibers reinforcement increases the flexural strength of provisional restorative resins. PMID:24431771

  12. Large-mode-area single-mode-output Neodymium-doped silicate glass all-solid photonic crystal fiber

    PubMed Central

    Li, Wentao; Chen, Danping; Qinling, Zhou; Hu, Lili

    2015-01-01

    We have demonstrated a 45 μm core diameter Neodymium-doped all-solid silicate glass photonic crystal fiber laser with a single mode laser output. The structure parameters and modes information of the fiber are both demonstrated by theoretical calculations using Finite Difference Time Domain (FDTD) method and experimental measurements. Maximum 0.8 W output power limited by launched pump power has been generated in 1064 nm with laser beam quality factor M2 1.18. PMID:26205850

  13. Thermal stress modification in regenerated fiber Bragg grating via manipulation of glass transition temperature based on CO₂-laser annealing.

    PubMed

    Lai, Man-Hong; Lim, Kok-Sing; Gunawardena, Dinusha S; Yang, Hang-Zhou; Chong, Wu-Yi; Ahmad, Harith

    2015-03-01

    In this work, we have demonstrated thermal stress relaxation in regenerated fiber Bragg gratings (RFBGs) by using direct CO₂-laser annealing technique. After the isothermal annealing and slow cooling process, the Bragg wavelength of the RFBG has been red-shifted. This modification is reversible by re-annealing and rapid cooling. It is repeatable with different cooling process in the subsequent annealing treatments. This phenomenon can be attributed to the thermal stress modification in the fiber core by means of manipulation of glass transition temperature with different cooling rates. This finding in this investigation is important for accurate temperature measurement of RFBG in dynamic environment. PMID:25723423

  14. Role of mast cells in wound healing process after glass - fiber composite implant in rats

    PubMed Central

    Rodella, L F; Rezzani, Rita; Buffoli, Barbara; Bonomini, Francesca; Tengattini, Sandra; Laffranchi, Laura; Paganelli, C; Sapelli, P L; Bianchi, Rossella

    2006-01-01

    Glass-fiber composites are frequently used in dentistry. In order to evaluate their biocompatibility we tested, in an experimental model “in vivo”, their tissue response pointing our attention on presence of mast cells (MCs) and fibrotic process. Sprague Dawley rats were used for the experimental design. The fibers were introduced in a subcutaneous pocket along the middle dorsal line between the two scapulas for 7, 14 or 21 days. At the end of the treatments the skins were excised and then processed for Toluidine Blue, to determine the presence of MCs, and Picrosirius Red staining, to evaluate the presence of fibrotic tissue. Our preliminary results showed and increase of both MC number and deposition of collagen type I, which characterized the fibrotic tissue. So, subsequent aims of our study were to evaluate the role played by MCs in tissue fibrosis and to give a possible explanation regarding the mechanisms that were responsible of biological response observed, through the analyses of some proteins, such as metalloproteinase-2 (MMP-2), its inhibitor (TIMP-2) and transforming growth factor-β (TGF-β). Our data confirmed the involvement of TGF-β, released by MCs, in the disruption of the equilibrium between MMP-2 and TIMP-2 that were implicated in the enhancement of fibrosis. In summary, this study demonstrate that this type of materials induced an inflammatory response at the site of implant and help to clarify what type of mechanism and which proteins are involved in this biological response. Nevertheless, more extensive investigations are in progress to better evaluate the inflammatory process. PMID:17125597

  15. Flexible nanocrystal-coated glass fibers for high-performance thermoelectric energy harvesting.

    PubMed

    Liang, Daxin; Yang, Haoran; Finefrock, Scott W; Wu, Yue

    2012-04-11

    Recent efforts on the development of nanostructured thermoelectric materials from nanowires (Boukai, A. I.; et al. Nature 2008, 451, (7175), 168-171; Hochbaum, A. I.; et al. Nature 2008, 451, (7175), 163-167) and nanocrystals (Kim, W.; et al. Phys. Rev. Lett. 2006, 96, (4), 045901; Poudel, B.; et al. Science 2008, 320, (5876), 634-638; Scheele, M.; et al. Adv. Funct. Mater. 2009, 19, (21), 3476-3483; Wang, R. Y.; et al. Nano Lett. 2008, 8, (8), 2283-2288) show the comparable or superior performance to the bulk crystals possessing the same chemical compositions because of the dramatically reduced thermal conductivity due to phonon scattering at nanoscale surface and interface. Up to date, the majority of the thermoelectric devices made from these inorganic nanostructures are fabricated into rigid configuration. The explorations of truly flexible composite-based flexible thermoelectric devices (See, K. C.; et al. Nano Lett. 2010, 10, (11), 4664-4667) have thus far achieved much less progress, which in principle could significantly benefit the conversion of waste heat into electricity or the solid-state cooling by applying the devices to any kind of objects with any kind of shapes. Here we report an example using a scalable solution-phase deposition method to coat thermoelectric nanocrystals onto the surface of flexible glass fibers. Our investigation of the thermoelectric properties yields high performance comparable to the state of the art from the bulk crystals and proof-of-concept demonstration also suggests the potential of wrapping the thermoelectric fibers on the industrial pipes to improve the energy efficiency. PMID:22409308

  16. Adsorption separation of terpene lactones from Ginkgo biloba L. extract using glass fiber membranes modified with octadecyltrichlorosilane.

    PubMed

    Su, I-Fang; Chen, Li-Jen; Suen, Shing-Yi

    2005-07-01

    In this study porous glass fiber membranes were modified by reaction with octadecyl-trichlorosilane to form C18 hydrophobic membranes. The contact angle and the CH2 vibration bands at 2855 and 2920 cm(-1) found by FTIR measurements verified the successful immobilization of C18 groups on the glass fiber membranes. The resulting C18 hydrophobic membranes were used to adsorb terpene lactones from crude Ginkgo biloba L. extracts. In batch adsorption processes, the modified C18 membranes exhibited a better adsorption performance than commercial C18 solid phase extraction adsorbents. Different desorption solvents were tested and ethyl acetate was found to preferentially desorb terpene lactones from the modified C18 membranes. In flow adsorption experiments at 1 mL/min, terpene lactone contents higher than 6 wt% (the standardized content) could be achieved in the elution step using ethyl acetate. PMID:16116999

  17. Effect of part thickness, glass fiber and crystallinity on light scattering during laser transmission welding of thermoplastics

    NASA Astrophysics Data System (ADS)

    Xu, Xin Feng; Parkinson, Alexander; Bates, Philip J.; Zak, Gene

    2015-12-01

    It is important to understand how laser energy scatters within the transparent component in order to predict and optimize the laser transmission welding process. This paper examines the influence of part thickness, glass fiber and crystallinity levels on the distribution of laser light after transmission through amorphous polycarbonate (PC) and semi-crystalline polymers such as polyamide 6 (PA6), polypropylene (PP), and polyethylene (PE). An experimental technique based on laser-scanned lines of progressively increasing power was used to assess the transmitted energy distribution. This distribution was characterized using a two-parameter model that captures scattered and un-scattered components of the laser beam. The results clearly show how the scattering is increased by increasing the numbers of interactions between laser light and phase boundaries either by increasing the particle concentration (i.e., glass fiber level and crystallinity) or increasing part thickness.

  18. An optical amplifier having 5 cm long silica-clad erbium doped phosphate glass fiber fabricated by "core-suction" technique

    NASA Astrophysics Data System (ADS)

    Goel, Nitin K.; Pickrell, Gary; Stolen, Roger

    2014-08-01

    We have fabricated an erbium-doped phosphate glass fiber with a silica cladding and used 5 cm length of it to form an optical amplifier. A bulk erbium phosphate glass called MM2 was used as a core glass in a silica cladding tube to prepare a preform using "core-suction" technique. This MM2 glass preform was drawn to a fiber and the resultant fiber was of good optical quality, free from air bubbles and major defects. The fiber was mechanically strong enough to allow for ease of handling and could be spliced to conventional silica fiber using commercial fusion splicer. This fiber was then used to setup an EDFA. Our work demonstrates the potential to form silica clad optical fibers with phosphate cores doped with very high levels of rare-earth ions. It is demonstrated that the core suction technique can be used to make a high-gain erbium phosphate fiber amplifier that is compatible with conventional silica fibers.

  19. Time-Dependent Deformation Modelling for a Chopped-Glass Fiber Composite for Automotive Durability Design Criteria

    SciTech Connect

    Ren, W

    2001-08-24

    Time-dependent deformation behavior of a polymeric composite with chopped-glass-fiber reinforcement was investigated for automotive applications, The material under stress was exposed to representative automobile service environments. Results show that environment has substantial effects on time-dependent deformation behavior of the material. The data were analyzed and experimentally-based models developed for the time-dependent deformation behavior as a basis for automotive structural durability design criteria.

  20. Investigation on Stress-Rupture Behavior of a Chopped-Glass-Fiber Composite for Automotive Durability Design Criteria

    SciTech Connect

    Ren, W

    2001-08-24

    Practical and inexpensive testing methods were developed to investigate stress-rupture properties of a polymeric composite with chopped glass fiber reinforcement for automotive applications. The material was tested in representative automotive environments to generate experimental data. The results indicate that environments have substantial effects on the stress-rupture behavior. The data were analyzed and developed into stress-rupture design criteria to address one of the durability aspects of the material for automotive structural applications.

  1. Coupled thermal/structural analyses of laser powered glass sealing methods for fiber optic and flat panel display applications

    SciTech Connect

    Chambers, R.S.; Gianoulakis, S.E.

    1996-12-31

    Glasses are used extensively by the electronics industry for packaging and in components. Because glasses have such low fracture toughness, glass components must maintain low tensile stresses to avoid cracking and ensure product stability. Modeling is a key tool for developing designs with low tensile stresses. Thermoelastic analyses are ideal for modeling slow, oven controlled processes where the temperature varies uniformly. Many processing environments, however, involve rapid heating and cooling cycles that produce nonhomogeneous temperature fields causing the volume and stresses in the glass to relax at different rates. This structural relaxation is an important nonlinear material behavior that gives rise to a point-to-point variability in effective properties of the material. To accurately model such stresses, a thermal analysis must be coupled to a structural analysis that employs a viscoelastic model of glass. Laser sealing of glasses is an example of a process where thermal history is an important factor in determining the residual stress state. Recent needs to consider laser sealing methods for fiber optic connectors and flat panel displays have spurred the development of coupled, three-dimensional thermal and structural finite element codes. Analyses of the temperatures and stresses generated in a flat panel display during a laser sealing operation are presented, an the idiosyncrasies and importance of modeling coupled thermal/structural phenomena are discussed.

  2. A new US manufacturing capability of glass preforms for fiber optics in defense programs. Final project report

    SciTech Connect

    Nath, D.K.

    1992-06-01

    The present project is a part of the program to develop ``A New US Manufacturing Capability of Fiber Optics in Defense Programs.`` The scope of the program extends beyond the limit of defense needs, impacting profoundly on important national issues such as, health industry vis-a-vis medical and insurance infrastructure as well as a great segment of commercial-industrial complex. At present, the glass preform -- critical raw material to produce the optical fiber, is 100% imported from Germany and Japan. Objectively, to create a domestic source, a cooperative project participated by Los Alamos and Polymicro began in the summer of 1991 to develop the cladding part of the glass preform. The goal was achieved by developing 0{center_dot}2NA preform, that was fabricated by Modified Chemical Vapor Deposition (MCVD) of born and fluorine doped silica glass as cladding layer on a silica substrate tube and collapsing the tube on a solid silica rod as the core. The preform was finally drawn into 200 micron core optical fiber and delivered to Los Alamos National Laboratory.

  3. Cheap glass fiber mats as a matrix of gel polymer electrolytes for lithium ion batteries

    NASA Astrophysics Data System (ADS)

    Zhu, Yusong; Wang, Faxing; Liu, Lili; Xiao, Shiyin; Yang, Yaqiong; Wu, Yuping

    2013-11-01

    Lithium ion batteries (LIBs) are going to play more important roles in electric vehicles and smart grids. The safety of the current LIBs of large capacity has been remaining a challenge due to the existence of large amounts of organic liquid electrolytes. Gel polymer electrolytes (GPEs) have been tried to replace the organic electrolyte to improve their safety. However, the application of GPEs is handicapped by their poor mechanical strength and high cost. Here, we report an economic gel-type composite membrane with high safety and good mechanical strength based on glass fiber mats, which are separator for lead-acid batteries. The gelled membrane exhibits high ionic conductivity (1.13 mS cm-1), high Li+ ion transference number (0.56) and wide electrochemical window. Its electrochemical performance is evaluated by LiFePO4 cathode with good cycling. The results show this gel-type composite membrane has great attraction to the large-capacity LIBs requiring high safety with low cost.

  4. Behavior of Fiber Glass Bolts, Rock Bolts and Cable Bolts in Shear

    NASA Astrophysics Data System (ADS)

    Li, Xuwei; Aziz, Naj; Mirzaghorbanali, Ali; Nemcik, Jan

    2016-07-01

    This paper experimentally compares the shear behavior of fiber glass (FG) bolt, rock bolt (steel rebar bolt) and cable bolt for the bolt contribution to bolted concrete surface shear strength, and bolt failure mode. Two double shear apparatuses of different size were used for the study. The tensile strength, the shear strength and the deformation modulus of bolt control the shear behavior of a sheared bolted joint. Since the strength and deformation modulus of FG bolt, rock bolt and cable bolt obtained from uniaxial tensile tests are different, their shear behavior in reinforcing joints is accordingly different. Test results showed that the shear stiffness of FG bolted joints decreased gradually from the beginning to end, while the shear stiffness of joints reinforced by rock bolt and cable bolt decreased bi-linearly, which is clearly consistent with their tensile deformation modulus. The bolted joint shear stiffness was highly influenced by bolt pretension in the high stiffness stage for both rock bolt and cable bolt, but not in the low stiffness stage. The rock bolt contribution to joint shear strength standardised by the bolt tensile strength was the largest, followed by cable bolts, then FG bolts. Both the rock bolts and cable bolts tended to fail in tension, while FG bolts in shear due to their low shear strength and constant deformation modulus.

  5. Ten year environmental test of glass fiber/epoxy pressure vessels

    NASA Technical Reports Server (NTRS)

    Faddoul, J. R.

    1985-01-01

    By the beginning of the 1970's composite pressure vessels had received a significant amount of development effort, and applications were beginning to be investigated. One of the first applications grew out of NASA Johnson Space Center efforts to develop a superior emergency breathing system for firemen. While the new breathing system provided improved wearer comfort and an improved mask and regulator, the primary feature was low weight which was achieved by using a glass fiber reinforced aluminum pressure vessel. Part of the development effort was to evaluate the long term performance of the pressure vessel and as a consequence, some 30 bottles for a test program were procured. These bottles were then provided to NASA Lewis Research Center where they were maintained in an outdoor environment in a pressurized condition for a period of up to 10 yr. During this period, bottles were periodically subjected to cyclic and burst testing. There was no protective coating applied to the fiberglass/epoxy composite, and significant loss in strength did occur as a result of the environment. Similar bottles stored indoors showed little, if any, degradation. This report contains a description of the pressure vessels, a discussion of the test program, data for each bottle, and appropriate plots, comparisons, and conclusions.

  6. Evaluation of Different Post Lengths’ Effect on Fracture Resistance of a Glass Fiber Post System

    PubMed Central

    Adanir, Necdet; Belli, Sema

    2008-01-01

    Objectives The purpose of this in vitro study was to evaluate the influence of different post lengths upon root fracture resistance. Methods 78 maxillary central teeth with similar dimensions were mounted in acrylic blocks with artificial silicone periodontal ligaments. Combinations of post lengths of 6 mm (shorter than 1/1 clinical crown length), 9 mm (1/1 clinical crown length), and 12 mm (longer than 1/1 clinical crown length) made up 6 different groups consisting of 13 teeth each. The glass fiber posts (Snowpost) were cemented with Super-Bond C&B and Panavia F luting cement. Composite-resin cores were made with Clearfil PhotoCore. The specimens were tested in a universal test machine. The testing machine applied controlled loads to the core, 2 mm from its incisal edge, on the palatal side at an angle 135 degrees to the long axis of the root. The testing machine was set at a crosshead speed of 5mm per minute. All samples were loaded until failure. Results There was no statistically significant difference between cements (P>.05). Posts shorter than clinical crown length, demonstrated root fracture under significantly lower loading forces (P<.05). Conclusion Usage of posts shorter than clinical crowns should be avoided to eliminate clinical failure. PMID:19212505

  7. Cheap glass fiber mats as a matrix of gel polymer electrolytes for lithium ion batteries

    PubMed Central

    Zhu, Yusong; Wang, Faxing; Liu, Lili; Xiao, Shiyin; Yang, Yaqiong; Wu, Yuping

    2013-01-01

    Lithium ion batteries (LIBs) are going to play more important roles in electric vehicles and smart grids. The safety of the current LIBs of large capacity has been remaining a challenge due to the existence of large amounts of organic liquid electrolytes. Gel polymer electrolytes (GPEs) have been tried to replace the organic electrolyte to improve their safety. However, the application of GPEs is handicapped by their poor mechanical strength and high cost. Here, we report an economic gel-type composite membrane with high safety and good mechanical strength based on glass fiber mats, which are separator for lead-acid batteries. The gelled membrane exhibits high ionic conductivity (1.13 mS cm−1), high Li+ ion transference number (0.56) and wide electrochemical window. Its electrochemical performance is evaluated by LiFePO4 cathode with good cycling. The results show this gel-type composite membrane has great attraction to the large-capacity LIBs requiring high safety with low cost. PMID:24216756

  8. Effects of Internal Bleaching on the Adhesion of Glass-Fiber Posts

    PubMed Central

    de Oliveira Moreira, Paulo E.; Pamplona, Lucianne S.; Nascimento, Gláucia C. R.; Esteves, Renata A.; Pessoa, Oscar F.; Silva, Cecy M.

    2015-01-01

    Objective: We evaluated the effects of internal bleaching on the adhesion of glass-fiber posts (GFPs) luted with different resin cements. Methods: Forty extracted human single-root teeth were endodontically treated and divided into four groups (n=10): G1- conventional resin cement (CRC); G2- self-adhesive resin cement (SARC); G3- bleaching + CRC; and G4- bleaching + SARC. Specimens were sectioned transversally into three slices to perform the push-out test at the coronal, middle and apical regions of the root canals. Data were analyzed using analysis of variance and Tukey's test (p<0.05). Results: The push-out bond strength of GFPs luted with SARC after bleaching (G4) was significantly lower than that of the other groups (p<0.001). We found no statistically significant differences in push-out bond strength among the other groups. Significance: Internal bleaching reduced the adhesion of GFPs luted with SARC. The adhesion of GFPs luted with CRC was not decreased after bleaching. PMID:26962369

  9. Cheap glass fiber mats as a matrix of gel polymer electrolytes for lithium ion batteries.

    PubMed

    Zhu, Yusong; Wang, Faxing; Liu, Lili; Xiao, Shiyin; Yang, Yaqiong; Wu, Yuping

    2013-01-01

    Lithium ion batteries (LIBs) are going to play more important roles in electric vehicles and smart grids. The safety of the current LIBs of large capacity has been remaining a challenge due to the existence of large amounts of organic liquid electrolytes. Gel polymer electrolytes (GPEs) have been tried to replace the organic electrolyte to improve their safety. However, the application of GPEs is handicapped by their poor mechanical strength and high cost. Here, we report an economic gel-type composite membrane with high safety and good mechanical strength based on glass fiber mats, which are separator for lead-acid batteries. The gelled membrane exhibits high ionic conductivity (1.13 mS cm(-1)), high Li(+) ion transference number (0.56) and wide electrochemical window. Its electrochemical performance is evaluated by LiFePO4 cathode with good cycling. The results show this gel-type composite membrane has great attraction to the large-capacity LIBs requiring high safety with low cost. PMID:24216756

  10. Research on the mechanical properties of a glass fiber reinforced polymer-steel combined truss structure.

    PubMed

    Liu, Pengfei; Zhao, Qilin; Li, Fei; Liu, Jinchun; Chen, Haosen

    2014-01-01

    An assembled plane truss structure used for vehicle loading is designed and manufactured. In the truss, the glass fiber reinforced polymer (GFRP) tube and the steel joint are connected by a new technology featuring a pretightened tooth connection. The detailed description for the rod and node design is introduced in this paper, and a typical truss panel is fabricated. Under natural conditions, the short-term load test and long-term mechanical performance test for one year are performed to analyze its performance and conduct a comparative analysis for a reasonable FEM model. The study shows that the design and fabrication for the node of an assembled truss panel are convenient, safe, and reliable; because of the creep control design of the rods, not only does the short-term structural stiffness meet the design requirement but also the long-term creep deformation tends towards stability. In addition, no significant change is found in the elastic modules, so this structure can be applied in actual engineering. Although the safety factor for the strength of the composite rods is very large, it has a lightweight advantage over the steel truss for the low density of GFRP. In the FEM model, simplifying the node as a hinge connection relatively conforms to the actual status. PMID:25247203

  11. Tribological and Mechanical Behaviors of Polyamide 6/Glass Fiber Composite Filled with Various Solid Lubricants

    PubMed Central

    Li, Duxin; Xie, Ying; Li, Wenjuan; You, Yilan; Deng, Xin

    2013-01-01

    The effects of polytetrafluoroethylene (PTFE), graphite, ultrahigh molecular weight polyethylene (UHMWPE), and their compounds on mechanical and tribological properties of glass-fiber-reinforced polyamide 6 (PA6/GF) were studied. The polymeric materials were blended using twin-screw extruder and subsequently injection molded for test samples. Mechanical properties were investigated in terms of hardness, tensile strength, and impact strength. Friction and wear experiments were run under ambient conditions at a rotating speed of 200 rpm and load of 100 N. The morphologies of the worn surfaces were also observed with scanning electron microscope. The results showed that graphite could increase the tensile strength of PA6/GF-15 composite, but the material became soft. Graphite/UHMWPE complex solid lubricants were effective in increasing the already high impact strength of PA6/GF-15 composite. 5% PTFE gave the maximum reduction in the coefficient of friction. However, PTFE/UHMWPE complex solid lubricants were the best choice for improving both friction and wear behaviors due to the lower friction coefficient and mass wear rate. Moreover, the worn surface of PA6 composites revealed that adhesive wear, abrasive wear, and fatigue wear occurred in this study. PMID:23766687

  12. Research on the Mechanical Properties of a Glass Fiber Reinforced Polymer-Steel Combined Truss Structure

    PubMed Central

    Liu, Pengfei; Zhao, Qilin; Li, Fei; Liu, Jinchun; Chen, Haosen

    2014-01-01

    An assembled plane truss structure used for vehicle loading is designed and manufactured. In the truss, the glass fiber reinforced polymer (GFRP) tube and the steel joint are connected by a new technology featuring a pretightened tooth connection. The detailed description for the rod and node design is introduced in this paper, and a typical truss panel is fabricated. Under natural conditions, the short-term load test and long-term mechanical performance test for one year are performed to analyze its performance and conduct a comparative analysis for a reasonable FEM model. The study shows that the design and fabrication for the node of an assembled truss panel are convenient, safe, and reliable; because of the creep control design of the rods, not only does the short-term structural stiffness meet the design requirement but also the long-term creep deformation tends towards stability. In addition, no significant change is found in the elastic modules, so this structure can be applied in actual engineering. Although the safety factor for the strength of the composite rods is very large, it has a lightweight advantage over the steel truss for the low density of GFRP. In the FEM model, simplifying the node as a hinge connection relatively conforms to the actual status. PMID:25247203

  13. Preparation and radar absorptive properties of BaFe12O19 -coated glass fiber

    NASA Astrophysics Data System (ADS)

    Jia, F.; Xu, M.; Bao, H. Q.; Cui, K.; Zhang, F.

    2016-07-01

    Traditional passive jamming materials such as chaff and foil showed some limitations in use because they can only reflect the electromagnetic wave. Therefore, to develop a kind of absorptive passive jamming material to make up for deficiencies of traditional passive jamming materials and improve the jamming efficiency is of great significance. In this paper, the BaFe12O19-coated glass fiber, used as a kind of radar absorptive chaff, was prepared by sol-gel dip-coating method. The effects of heat treatment temperature, heat treatment time and coating times on film quality, tensile strength and attenuation efficiency of the samples were discussed. The study shows that an increase of the heat treatment temperature and an extension of the heat treatment time is conducive to the growth of barium ferrite grain, while they would introduce the loss of chaff strength at the same time. In addition, multi-coating process can improve the film quality and attenuation efficiency of the sample. Data show that the 10 times coated samples have a best reflectivity of (15GHz, -6.65dB) and the bandwidth of reflectivity lower than -5dB is11.8 GHz. According to the test results, the prepared material has certain attenuation efficiency in the range of 2GHz-18GHz, having a high practical value.

  14. Prediction of cutting forces in machining of unidirectional glass fiber reinforced plastics composite

    NASA Astrophysics Data System (ADS)

    Gill, Surinder Kumar; Gupta, Meenu; Satsangi, P. S.

    2013-06-01

    Machining of plastic materials has become increasingly important in any engineering industry subsequently the prediction of cutting forces. Forces quality has greater influence on components, which are coming in contact with each other. So it becomes necessary to measure and study machined forces and its behavior. In this research work, experimental investigations are conducted to determine the effects of cutting conditions and tool geometry on the cutting forces in the turning of the unidirectional glass fiber reinforced plastics (UD-GFRP) composites. In this experimental study, carbide tool (K10) having different tool nose radius and tool rake angle is used. Experiments are conducted based on the established Taguchi's technique L18 orthogonal array on a lathe machine. It is found that the depth of cut is the cutting parameter, which has greater influence on cutting forces. The effect of the tool nose radius and tool rake angles on the cutting forces are also considerably significant. Based on statistical analysis, multiple regression model for cutting forces is derived with satisfactory coefficient ( R 2). This model proved to be highly preferment for predicting cutting forces.

  15. Preparation and characterization of glass fibers - polymers (epoxy) bars (GFRP) reinforced concrete for structural applications

    NASA Astrophysics Data System (ADS)

    Alkjk, Saeed; Jabra, Rafee; Alkhater, Salem

    2016-06-01

    The paper presents some of the results from a large experimental program undertaken at the Department of Civil Engineering of Damascus University. The project aims to study the ability to reinforce and strengthen the concrete by bars from Epoxy polymer reinforced with glass fibers (GFRP) and compared with reinforce concrete by steel bars in terms of mechanical properties. Five diameters of GFRP bars, and steel bars (4mm, 6mm, 8mm, 10mm, 12mm) tested on tensile strength tests. The test shown that GFRP bars need tensile strength more than steel bars. The concrete beams measuring (15cm wide × 15cm deep × and 70cm long) reinforced by GFRP with 0.5 vol.% ratio, then the concrete beams reinforced by steel with 0.89 vol.% ratio. The concrete beams tested on deflection test. The test shown that beams which reinforced by GFRP has higher deflection resistance, than beams which reinforced by steel. Which give more advantage to reinforced concrete by GFRP.

  16. Natural Weathering and Sea Water Effects on the Durability of Glass Fiber Reinforced Vinylester: Fractographic Analysis

    NASA Astrophysics Data System (ADS)

    Merah, Nesar; Nizamuddin, Seyed; Khan, Zafarullah; Al-Sulaiman, Faleh; Mehdi, Moeid

    2010-10-01

    This paper presents a study of the effects of harsh outdoor weather and warm sea water on the tensile behavior of Glass-Fiber Reinforced Vinylester (GFRV) pipe materials destined for sea water handling and transportation. The effect of Dhahran’s outdoor weather for exposure periods ranging from 3 to 36 months revealed an improvement in tensile strength when compared with the as received GFRV sample. A significant increasing trend of tensile strength from 3 to 12 months was noted. This is attributed mainly to the post curing effects resulting in higher cross linking density. After 12 months of exposure the tensile strength showed a decreasing trend, but remaining still higher than the average tensile strength of as received (baseline) GFRV sample. Similar results of enhanced tensile strength were noted after immersion of GFRV pipes in warm Gulf sea water for 12 months. Fractographic analysis was performed on the tensile tested GFRV samples using optical microscope followed by scanning electron microscope (SEM). The characterization of the controlling failure mechanisms involved from fracture initiation to fracture propagation through the gage section of the specimen were predicted and were justified by correlating the optical and SEM pictures.

  17. Glass fiber reinforced plastics within the fringe and flexure tracker of LINC-NIRVANA

    NASA Astrophysics Data System (ADS)

    Smajic, Semir; Eckart, A.; Horrobin, M.; Lindhorst, B.; Pott, J.-U.; Rauch, C.; Rost, S.; Straubmeier, C.; Tremou, E.; Wank, I.; Zuther, J.

    2012-07-01

    The Fringe and Flexure Tracking System (FFTS) is meant to monitor and correct atmospheric piston varia­ tion and instrumental vibrations and flexure during near-infrared interferometric image acquisition of LING­ NIRVANA. In close work with the adaptive optics system the FFTS enables homothetic imaging for the Large Binocular Telescope. One of the main problems we had to face is the connection between the cryogenic upper part of the instrument, e.g. detector head, and the lower ambient temperature part. In this ambient temperature part the moving stages are situated that move the detector head in the given field of view (FOV). We show how we solved this problem using the versatile material glass fiber reinforced plastics (GFRP's) and report in what way this material can be worked. We discuss in detail the exquisite characteristics of this material which we use to combine the cryogenic and ambient environments to a fully working system. The main characteristics that we focus on are the low temperature conduction and the tensile strength of the GFRP's. The low temperature conduction is needed to allow for a low heat-exchange between the cryogenic and ambient part whereas the tensile strength is needed to support heavy structures like the baffle motor and to allow for a minimum of flexure for the detector head. Additionally, we discuss the way we attached the GFRP to the remaining parts of the FFTS using a two component encapsulant.

  18. Tribological and mechanical behaviors of polyamide 6/glass fiber composite filled with various solid lubricants.

    PubMed

    Li, Duxin; Xie, Ying; Li, Wenjuan; You, Yilan; Deng, Xin

    2013-01-01

    The effects of polytetrafluoroethylene (PTFE), graphite, ultrahigh molecular weight polyethylene (UHMWPE), and their compounds on mechanical and tribological properties of glass-fiber-reinforced polyamide 6 (PA6/GF) were studied. The polymeric materials were blended using twin-screw extruder and subsequently injection molded for test samples. Mechanical properties were investigated in terms of hardness, tensile strength, and impact strength. Friction and wear experiments were run under ambient conditions at a rotating speed of 200 rpm and load of 100 N. The morphologies of the worn surfaces were also observed with scanning electron microscope. The results showed that graphite could increase the tensile strength of PA6/GF-15 composite, but the material became soft. Graphite/UHMWPE complex solid lubricants were effective in increasing the already high impact strength of PA6/GF-15 composite. 5% PTFE gave the maximum reduction in the coefficient of friction. However, PTFE/UHMWPE complex solid lubricants were the best choice for improving both friction and wear behaviors due to the lower friction coefficient and mass wear rate. Moreover, the worn surface of PA6 composites revealed that adhesive wear, abrasive wear, and fatigue wear occurred in this study. PMID:23766687

  19. Damage localization in a glass fiber reinforced composite plate via the surface interpolation method

    NASA Astrophysics Data System (ADS)

    Limongelli, M. P.; Carvelli, V.

    2015-07-01

    This work deals with the application to composite plates of the surface interpolation method (SIM) for damage localization. The procedure, which is a generalization to the two-dimensional case of the previously published Interpolation Damage Detection Method (IDDM), locates reductions of stiffness in two-dimensional structures such as plates. The method is based on the damage sensitive of a spline function accuracy in fitting the operational displacement shapes, relies on the so-called Gibbs’ phenomenon for splines. This phenomenon occurs when a spline function interpolates discontinuous functions and consists in sharp oscillations and overshoots (values higher than those of the function to be interpolated) near a discontinuous point. The operational deformed shapes are recovered from frequency response functions (FRF's) measured at different locations of the structure during vibrations. The accuracy of the spline interpolation is measured by an error function defined as the difference between the measured and interpolated operational deformed shapes. At a certain location an increase (statistically meaningful) of the interpolation error, with respect to a reference configuration, points out a localized variation of the operational shapes thus revealing the existence of damage. The accuracy of the surface interpolation method is experimentally assessed by impact hammer tests on glass fiber/vinylester composite plates progressively damaged and using finite element numerical modelling.

  20. Preparation and characterization of fibrous chitosan-glued phosphate glass fiber scaffolds for bone regeneration.

    PubMed

    Zheng, Kai; Wu, Zhaoying; Wei, Jie; Rűssel, Christian; Liang, Wen; Boccaccini, Aldo R

    2015-08-01

    Phosphate glass fibers (PGF) have emerged as promising building blocks for constructing bone scaffolds. In this study, fibrous scaffolds (PGFS) were fabricated using a facile binding method at room temperature. PGFS exhibited an extracellular matrix-like morphology and were composed of PGF as matrix and chitosan as the natural binding glue. They showed an interconnected porous structure with a porosity of ~87% and pore size of 100-500 µm. PGFS exhibited the typical compressive stress-strain behaviour of highly porous, low-density, open-cell scaffolds. Their yield stress and modulus were ~0.38 and ~2.84 MPa, respectively, with the strength being higher than the lower bound of the compressive strength of cancellous bone. PGFS were degradable and the weight loss was about 25% after immersion in stimulated body fluid (SBF) for 28 days. In addition, the yield stress and the modulus decreased with increasing immersion time in SBF. Apatite formation could be detected on the surface of PGFS within 7 days of immersion in SBF. MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) assay indicated that PGFS were non-cytotoxic against bone marrow stromal cells (bMSCs) after culture for up to 72 h. These results suggest that PGFS could be promising scaffolds for bone regeneration applications. PMID:26271217

  1. Influence of Copper Layer Content in the Elastic and Damping Behavior of Glass-Fiber/Epoxy-Resin Composites

    NASA Astrophysics Data System (ADS)

    Carneiro, V. H.; Capela, P.; Teixeira, J. C.; Teixeira, S.; Cerqueira, F.; Macedo, F.; Ribas, L.; Soares, D.

    2016-06-01

    The impact in the elastic behavior and internal friction, caused by the introduction of Copper layers in Glass-Fiber/Epoxy Resin composites and temperature effects, were studied and evaluated recurring to Dynamic Mechanical Analysis. It is shown that the introduction of Copper layers increases the storage modulus of the composites and delays their glass transition temperature, however, it allows a faster transformation. Additionally, it is concluded that the introduction of Copper layers elevates the internal friction during the glass transition phase by the inversion of the deformation mechanism due to thermal expansion and increase in the Poisson's ratio of the epoxy resin to a value near 0.5 where its deformation is approximately isochoric. This increase in damping capacity is relevant in application with cyclic fatigue and mechanical vibration.

  2. Efficient and long-lived Zeeman-sublevel atomic population storage in an erbium-doped glass fiber

    NASA Astrophysics Data System (ADS)

    Saglamyurek, Erhan; Lutz, Thomas; Veissier, Lucile; Hedges, Morgan P.; Thiel, Charles W.; Cone, Rufus L.; Tittel, Wolfgang

    2015-12-01

    Long-lived population storage in optically pumped levels of rare-earth ions doped into solids, referred to as persistent spectral hole burning, is of significant fundamental and technological interest. However, the demonstration of deep and persistent holes in rare-earth ion doped amorphous hosts, e.g., glasses, has remained an open challenge for many decades—a fact that motivates our work towards a better understanding of the interaction between impurities and vibrational modes in glasses. Here we report the observation and detailed characterization of such holes in an erbium-doped silica glass fiber cooled to below 1 K. We demonstrate population storage in electronic Zeeman sublevels of the erbium ground state with lifetimes up to 30 seconds and 80% spin polarization. In addition to its fundamental aspect, our investigation reveals a potential technological application of rare-earth ion doped amorphous materials, including at telecommunication wavelength.

  3. Fatigue surviving, fracture resistance, shear stress and finite element analysis of glass fiber posts with different diameters.

    PubMed

    Wandscher, Vinícius Felipe; Bergoli, César Dalmolin; de Oliveira, Ariele Freitas; Kaizer, Osvaldo Bazzan; Souto Borges, Alexandre Luiz; Limberguer, Inácio da Fontoura; Valandro, Luiz Felipe

    2015-03-01

    This study evaluated the shear stress presented in glass fiber posts with parallel fiber (0°) and different coronal diameters under fatigue, fracture resistance and FEA. 160 glass-fiber posts (N=160) with eight different coronal diameters were used (DT=double tapered, number of the post=coronal diameter and W=Wider - fiber post with coronal diameter wider than the conventional): DT1.4; DT1.8W; DT1.6; DT2W; DT1.8; DT2.2W; DT2; DT2.2. Eighty posts were submitted to mechanical cycling (3×10(6) cycles; inclination: 45°; load: 50N; frequency: 4Hz; temperature: 37°C) to assess the surviving under intermittent loading and other eighty posts were submitted to fracture resistance testing (resistance [N] and shear-stress [MPa] values were obtained). The eight posts types were 3D modeled (Rhinoceros 4.0) and the shear-stress (MPa) evaluated using FEA (Ansys 13.0). One-way ANOVA showed statistically differences to fracture resistance (DT2.2W and DT2.2 showed higher values) and shear stress values (DT1.4 showed lower values). Only the DT1.4 fiber posts failed after mechanical cycling. FEA showed similar values of shear stress between the groups and these values were similar to those obtained by shear stress testing. The failure analysis showed that 95% of specimens failed by shear. Posts with parallel fiber (0°) may suffer fractures when an oblique shear load is applied on the structure; except the thinner group, greater coronal diameters promoted the same shear stresses. PMID:25553557

  4. Electrical recordings from the accessory olfactory bulb in VNO-AOB ex vivo preparations.

    PubMed

    Meeks, Julian P; Holy, Timothy E

    2013-01-01

    Electrical recordings from individual accessory olfactory bulb neurons allow exploration of the functional properties of this important pheromonal processing circuit. Several approaches to performing such recordings have been used. Here, we describe ex vivo methods that we have found useful for recording from accessory olfactory bulb neurons using simple extracellular glass electrodes. PMID:24014366

  5. The influence of glass fibers on elongational viscosity studied by means of optical coherence tomography and X-ray computed tomography

    SciTech Connect

    Aigner, M. Köpplmayr, T. E-mail: Christian.lang@jku.at; Lang, C. E-mail: Christian.lang@jku.at; Burzic, I. E-mail: juergen.miethlinger@jku.at; Miethlinger, J. E-mail: juergen.miethlinger@jku.at; Salaberger, D.; Buchsbaum, A. Leitner, M.; Heise, B.; Schausberger, S. E. Stifter, D.

    2014-05-15

    We report on the flow characteristics of glass-fiber-reinforced polymers in elongational rheometry. Unlike polymers with geometrically isotropic fillers, glass-fiber-reinforced polymers exhibit flow behavior and rheology that depend heavily on the orientation, the length distribution and the content of the fibers. One of the primary objectives of this study was to determine the effect of fiber orientation, concentration and distribution on the entrance pressure drop by means of optical coherence tomography (OCT), full-field optical coherence microscopy (FF-OCM), and X-ray computed tomography (X-CT). Both pressure drop and melt flow were analyzed using a special elongation die (Thermo Scientific X-Die [3]) for inline measurements. Samples with a variety of fiber volume fractions, fiber lengths and processing temperatures were measured.

  6. Influence of screw holes and gamma sterilization on properties of phosphate glass fiber-reinforced composite bone plates.

    PubMed

    Han, Na; Ahmed, Ifty; Parsons, Andrew J; Harper, Lee; Scotchford, Colin A; Scammell, Brigitte E; Rudd, Chris D

    2013-05-01

    Polymers prepared from polylactic acid (PLA) have found a multitude of uses as medical devices. For a material that degrades, the main advantage is that an implant would not necessitate a second surgical event for removal. In this study, fibers produced from a quaternary phosphate-based glass (PBG) in the system 50P2O5-40CaO-5Na2O-5Fe2O3 were used to reinforce PLA polymer. The purpose of this study was to assess the effect of screw holes in a range of PBG-reinforced PLA composites with varying fiber layup and volume fraction. The flexural properties obtained showed that the strength and modulus values increased with increasing fiber volume fraction; from 96 MPa to 320 MPa for strength and between 4 GPa and 24 GPa for modulus. Furthermore, utilizing a larger number of thinner unidirectional (UD) fiber prepreg layers provided a significant increase in mechanical properties, which was attributed to enhanced wet out and thus better fiber dispersion during production. The effect of gamma sterilization via flexural tests showed no statistically significant difference between the sterilized and nonsterilized samples, with the exception of the modulus values for samples with screw holes. Degradation profiles revealed that samples with screw holes degraded faster than those without screw holes due to an increased surface area for the plates with screw holes in PBS up to 30 days. Scanning electron microscope (SEM) analysis revealed fiber pullout before and after degradation. Compared with various fiber impregnation samples, with 25% volume fraction, 8 thinner unidirectional prepreg stacked samples had the shortest fiber pull-out lengths in comparison to the other samples investigated. PMID:22207606

  7. Er3+ doped germanate-tellurite glass for mid-infrared 2.7 μm fiber laser material

    NASA Astrophysics Data System (ADS)

    Lu, Yu; Cai, Muzhi; Cao, Ruijie; Qian, Shan; Xu, Shiqing; Zhang, Junjie

    2016-03-01

    2.7 μm fluorescence has been achieved in the different concentration Er3+ doped germanate-tellurite glasses. The germanate-tellurite glass shows a good thermal stability and Fourier transform infrared spectra indicates that the mid-infrared transmission spectra performance is good. Based on the measured absorption spectra, the Judd-Ofelt parameters were calculated and discussed. Moreover, the emission spectra of Er3+ doped glasses show that the emission intensity at ~2.7 μm reaches a maximal value and no obvious concentration quenching phenomenon happens even if the ErF3-doping concentration is 1.5 mol%. In addition, the 2.7 μm radiative transition probability and emission cross section is 35.57 s-1 and 13.87×10-21 cm2 corresponding to the Er3+:4I11/2→4I13/2 transition and superior gain performance was also obtained from the prepared glass. Meanwhile, energy transfer mechanism has been investigated in detail. Hence, the spectroscopic characteristics as well as the good thermal property indicate that this kind of glass is an attractive host for developing mid-infrared fiber laser.

  8. Influence of instrumentation techniques and irrigating solutions on bond strength of glass fiber posts to root dentin.

    PubMed

    Marques, Eduardo Fernandes; Bueno, Carlos Eduardo da Silveira; Veloso, Heloisa Helena Pinho; Almeida, Gustavo; Pinheiro, Sergio Luiz

    2014-01-01

    This study sought to evaluate how instrumentation techniques and irrigating solutions affected the bond strength of glass fiber posts. For this study, 80 human maxillary central incisors were selected. Endodontic access was obtained, root canal length was measured, and the coronal third was prepared using Gates-Glidden drills. The specimens were embedded in acrylic resin and randomly assigned to 8 groups (n = 10): manual instrumentation only (Group 1), rotary instrumentation only (Group 2), irrigation with 2.5% sodium hypochlorite (NaOCl) (Group 3), irrigation with 2% chlorhexidine (CHX) (Group 4), manual instrumentation and irrigation with 2.5% NaOCl (Group 5), manual instrumentation and irrigation with 2% CHX (Group 6), rotary instrumentation and irrigation with 2.5% NaOCl (Group 7), and rotary instrumentation and irrigation with 2% CHX (Group 8). Specimens in Groups 5-8 also received a 1 minute final rinse with ethylenediaminetetraacetic acid. Canals were filled and the specimens stored for 30 days in distilled water. The restoration material was removed down to the apical 4 mm of the root canal. The glass fiber posts were luted with resin cement and stored for 24 hours at 37°C. Specimens were subjected to a tensile strength test at a constant speed of 1.0 mm/minute and a load of 2,000 kgf. The results were analyzed by analysis of variance and Tukey's test. Irrigation with 2.5% NaOCl reduced the bond strength of fiber posts significantly (P < 0.01), while CHX showed no effect (P > 0.05). It was concluded that irrigation with 2.5% NaOCl has a negative effect on micromechanical retention of glass fiber posts, whether manual or rotary instrumentation is used. PMID:24598496

  9. A Comparative Evaluation of Effect of Different Chemical Solvents on the Shear Bond Strength of Glass Fiber reinforced Post to Core Material

    PubMed Central

    Samadi, Firoza; Jaiswal, JN; Saha, Sonali

    2014-01-01

    ABSTRACT% Aim: To compare the effect of different chemical solvents on glass fiber reinforced posts and to study the effect of these solvents on the shear bond strength of glass fiber reinforced post to core material. Materials and methods: This study was conducted to evaluate the effect of three chemical solvents, i.e. silane coupling agent, 6% H2O2 and 37% phosphoric acid on the shear bond strength of glass fiber post to a composite resin restorative material. The changes in post surface characteristics after different treatments were also observed, using scanning electron microscopy (SEM) and shear bond strength was analyzed using universal testing machine (UTM). Results: Surface treatment with hydrogen peroxide had greatest impact on the post surface followed by 37% phosphoric acid and silane. On evaluation of the shear bond strength, 6% H2O2 exhibited the maximum shear bond strength followed in descending order by 37% phosphoric acid and silane respectively. Conclusion: The surface treatment of glass fiber post enhances the adhesion between the post and composite resin which is used as core material. Failure of a fiber post and composite resin core often occurs at the junction between the two materials. This failure process requires better characterization. How to cite this article: Sharma A, Samadi F, Jaiswal JN, Saha S. A Comparative Evaluation of Effect of Different Chemical Solvents on the Shear Bond Strength of Glass Fiber Reinforced Post to Core Material. Int J Clin Pediatr Dent 2014;7(3):192-196. PMID:25709300

  10. Intense visible upconversion and energy transfer in Ho3+/Yb3+ codoped tellurite glasses for potential fiber laser

    NASA Astrophysics Data System (ADS)

    Peng, Shengxi; Wu, Libo; Wang, Bo; Yang, Fengjing; Qi, Yawei; Zhou, Yaxun

    2015-03-01

    New Ho3+/Yb3+ codoped tellurite glasses (TeO2-Bi2O3-ZnO-Na2O) prepared by melt-quenching technique were investigated to realize visible-band upconversion emissions applied for compact fiber lasers. The absorption spectra, upconversion emission spectra, differential scanning calorimetry (DSC) curves, X-ray diffraction (XRD) and Raman spectra were measured to characterize the spectroscopic properties of Ho3+, thermal stability and structural nature of glass hosts. Under the excitation of 980 nm laser diode (LD), the intense green (∼543 nm) and red (∼657 nm) upconversion emissions corresponding to 5F4(5S2) → 5I8 and 5F5 → 5I8 transitions of Ho3+ respectively are simultaneously observed. The power dependence study of upconversion intensities on excited pump power revealed that the Ho3+ population at 5F4(5S2) and 5F5 levels was originated from two-photon absorption process based on the energy transfer from Yb3+ to Ho3+. The energy transfer mechanism from Yb3+ to Ho3+ was investigated and relevant micro-parameters (energy transfer coefficient and critical radius) and phonon contribution ratio were presented. With the increase of Yb3+ doped concentration, both the green and red upconversion intensities enhanced greatly, meanwhile the thermal stability of glass hosts, characterized by the three characteristic temperatures, also got a slight improvement. Furthermore, the glass structure was briefly analyzed with the calculated Judd-Ofelt intensity parameters, the measured Raman spectra and XRD curves. The present results indicate that the new synthesized Ho3+/Yb3+ codoped tellurite glass with intense green and red upconversion emissions is a promising medium applied for the visible-band fiber lasers.

  11. Enhanced osteoprogenitor elongated collagen fiber matrix formation by bioactive glass ionic silicon dependent on Sp7 (osterix) transcription.

    PubMed

    Varanasi, Venu G; Odatsu, Tetsurou; Bishop, Timothy; Chang, Joyce; Owyoung, Jeremy; Loomer, Peter M

    2016-10-01

    Bioactive glasses release ions, those enhance osteoblast collagen matrix synthesis and osteogenic marker expression during bone healing. Collagen matrix density and osteogenic marker expression depend on osteogenic transcription factors, (e.g., Osterix (OSX)). We hypothesize that enhanced expression and formation of collagen by Si(4+) depends on enhanced expression of OSX transcription. Experimental bioactive glass (6P53-b) and commercial Bioglass(TM) (45S5) were dissolved in basal medium to make glass conditioned medium (GCM). ICP-MS analysis was used to measure bioactive glass ion release rates. MC3T3-E1 cells were cultured for 20 days, and gene expression and extracellular matrix collagen formation was analyzed. In a separate study, siRNA was used to determine the effect of OSX knockdown on impacting the effect of Si(4+) on osteogenic markers and matrix collagen formation. Each bioactive glass exhibited similar ion release rates for all ions, except Mg(2+) released by 6P53-b. Gene expression results showed that GCM markedly enhanced many osteogenic markers, and 45S5 GCM showed higher levels of expression and collagen matrix fiber bundle density than 6P53-b GCM. Upon knockdown of OSX transcription, collagen type 5, alkaline phosphatase, and matrix density were not enhanced as compared to wild type cells. This study illustrates that the enhancement of elongated collagen fiber matrix formation by Si(±) depends on OSX transcription. © 2016 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 104A: 2604-2615, 2016. PMID:27279631

  12. Acid Etching and Surface Coating of Glass-Fiber Posts: Bond Strength and Interface Analysis.

    PubMed

    Cecchin, Doglas; Farina, Ana Paula; Vitti, Rafael Pino; Moraes, Rafael Ratto; Bacchi, Ataís; Spazzin, Aloísio Oro

    2016-01-01

    The aim of this study was to evaluate the bond strength of a composite resin to glass-fiber post (GFP) treated or not with phosphoric acid, silane coupling agent, and unfilled resin. GFPs were etched or not with 37% phosphoric acid and different surface coating applied: silane coupling agent, unfilled resin, or both. Composite resin blocks were built around a 4-mm height on the GFP. Unfilled resin (20 s) and composite resin (40 s) were light activated by a light-emitting diode unit. The specimens were stored in distilled water at 37 °C for 24 h. Microtensile bond test was performed using a mechanical testing machine until failure (n=10). The data were analyzed using two-way ANOVA followed by Student-Newman-Keuls' test (p<0.05). Failure modes were classified as adhesive, mixed, or cohesive failures. Additional specimens (n=3) were made to analyze the bonded interfaces by scanning electron microscopy. The statistical analysis showed the factor 'surface coating' was significant (p<0.05), whereas the factor 'HP etching' (p=0.131) and interaction between the factors (p=0.171) were not significant. The highest bond strength was found for the silane and unfilled resin group (p<0.05). A predominance of adhesive and cohesive failures was found. Differences regarding the homogeneity and thickness of the unfilled resin layer formed by different GFP surface treatments were observed. The application of silane and unfilled resin can improve the bond strength between GFP and resin composite. PMID:27058389

  13. Bond variability of glass-fiber-reinforcing-plastic reinforcement in concrete

    SciTech Connect

    Hanus, J.P.

    1998-12-01

    This report summarizes an experimental program that investigated the bond variability of glass-fiber-reinforced-polymer (GFRP) reinforcement in concrete. The variables in the study were manufacturer (Marshall Industries Composites, Incorporated M1 and Corrosion Proof Products/Hughes Brothers M2), bar size (Number 5 and 6), cover (2 and 3 bar diameters), and embedment length (10 through 47 inch). Tensile tests were also performed on the GFRP rebar for comparison to bond tests that exhibited bar failure. Eighty-four inverted half-beam bond specimens were tested while monitoring load, loaded-end slip, free-end slip, cracking, and acoustic emissions on the embedded bar and concrete. Three to six replicate tests were conducted for each set of variables. The results of each test within a series were examined to investigate the relative variability with respect to the failure types. The M1 rebar was observed to rely primarily on mechanical interlock to develop bond strength. This conclusion was based on investigations of the rebar surface condition, bar deformation geometry, slip curves, AE results, crack patterns and forensic investigations. Additionally, the ultimate loads for the bond tests with the Ml rebar were affected by changes in embedment lengths but did not vary for tests with 2 and 3d(b) cover. Overall, the M1 rebar had coefficients of variation (COV) of 14.3 and 8.9% for bond tests that exhibited bar failure and tensile test bar failures, respectively. The bond tests that failed in concrete splitting had COVs from 5.2 to 5.9%.

  14. Atomically smooth hybrid crystalline-core glass-clad fibers for low-loss broadband wave guiding.

    PubMed

    Lai, Chien-Chih; Lo, Chia-Yao; Nguyen, Duc Huy; Huang, Jian-Zhi; Tsai, Wan-Shao; Ma, Yuan-Ron

    2016-09-01

    We demonstrate direct evidence for the first realization of atomically smooth sapphire crystalline fiber cores with a surface variation of only ~1.9 Å. The hybrid glass-clad crystalline cores were grown by a laser-based fiber drawing technique. Because of the improvement in crystal fiber quality, we were able, for the first time, to comprehensively and quantitatively elucidate the correlation between fiber nanostructure and optical loss. We also experimentally demonstrated that high-temperature treatment has a significant impact on defect relaxation and promotes excellent crystallinity, and hence enables low-loss optical wave guiding. The experimentally measured propagation losses in the order of 0.01-0.1 dB/cm are the lowest ever reported among conventional Ti:sapphire channel waveguides and ultrafast-laser-inscribed waveguides, and agree well with the theory. Through experiments and numerical calculation, we have demonstrated that low threshold and high efficiency of Ti:sapphire crystal fiber lasers are possible with the atomic-level roughness, low-loss propagation, and high crystallinity of the Ti:sapphire crystalline core. PMID:27607618

  15. Luffa-sponge-like glass-TiO2 composite fibers as efficient photocatalysts for environmental remediation.

    PubMed

    Ma, Zhijun; Chen, Weibo; Hu, Zhongliang; Pan, Xuanzhao; Peng, Mingying; Dong, Guoping; Zhou, Shifeng; Zhang, Qinyuan; Yang, Zhongmin; Qiu, Jianrong

    2013-08-14

    Structural design of photocatalysts is of great technological importance for practical applications. A rational design of architecture can not only promote the synthetic performance of photocatalysts but also bring convenience in their application procedure. Nanofibers have been established as one of the most ideal architectures of photocatalysts. However, simultaneous optimization of the photocatalytic efficiency, mechanical strength, and thermal/chemical tolerance of nanofibrous photocatalysts remains a big challenge. Here, we demonstrate a novel design of TiO2-SiO2 composite fiber as an efficient photocatalyst with excellent synthetic performance. Core-shell mesoporous SiO2 fiber with high flexibility was employed as the backbone for supporting ultrasmall TiO2 nanowhiskers of the anatase phase, constructing core@double-shell fiber with luffa-sponge-like appearance. Benefitting from their continuously long fibrous morphology, highly porous structure, and completely inorganic nature, the TiO2-SiO2 composite fibers simultaneously possess high photocatalytic reactivity, good flexibility, and excellent thermal and chemical stability. This novel architecture of TiO2-SiO2 glass composite fiber may find extensive use in the environment remediation applications. PMID:23862682

  16. Ge-Sb-Se glass fiber-optics for in-vivo mid-infrared optical biopsy

    NASA Astrophysics Data System (ADS)

    Parnell, H.; Butterworth, J. H.; Sakr, H.; Tang, Z.; Furniss, D.; Benson, T. M.; Scotchford, C.; Seddon, A. B.

    2016-03-01

    In the UK, it is now recognised that 1 in 2 people born after 1960 will develop some form of cancer during their lifetime. Diagnosing patients whilst in the early stages drastically improves their chances of survival but up until now the gold standard for cancer detection is via a lengthy excision biopsy procedure, which relies on the skill of a histopathologist. Evidently, the need for a faster solution is paramount. The mid-infrared (MIR) spectral region covers the wavelengths 3-25 μm and characteristic vibrational spectra unique to each molecular type. Subtle changes in the specific spectral response within this region are indicative of changes within the cells relative to normal cells, signifying the presence or absence of a disease. Our goal is to carry out disease diagnosis in vivo. Reaching these wavelengths has previously presented difficulties as conventional MIR blackbody light sources are weak and optical fibers for transmitting MIR light to/from tissue in vivo can be limited by strong material absorption such as silica glass >2.4 μm and tellurite, and heavy metal fluoride, >4.75 μm. However, chalcogenide glasses have been shown to transmit MIR light out to 25 μm. This paper reports on a glass composition in the Ge-Sb-Se system and its suitability as an optical fiber for the transmission of MIR to and from tissue samples, enabling in vivo mapping for an immediate diagnostic response- a technique termed `optical biopsy'.

  17. In vitro performance of 13-93 bioactive glass fiber and trabecular scaffolds with MLO-A5 osteogenic cells.

    PubMed

    Modglin, Vernon C; Brown, Roger F; Fu, Qiang; Rahaman, Mohamed N; Jung, Steven B; Day, Delbert E

    2012-10-01

    This in vitro study was performed to evaluate the ability of two types of porous bioactive glass scaffolds to support the growth and differentiation of an established osteogenic cell line. The two scaffold types tested included 13-93 glass fiber and trabecular-like scaffolds seeded with murine MLO-A5 cells and cultured for intervals of 2 to 12 days. Culture in MTT-containing medium showed metabolically active cells both on the surface and within the interior of the scaffolds. Scanning electron microscopy revealed well-attached cells on both types of scaffolds with a continual increase in cell density over a 6-day period. Protein measurements also showed a linear increase in cell density during the incubation. Activity of alkaline phosphatase, a key indicator of osteoblast differentiation, increased about 10-fold during the 6-day incubation with both scaffold types. The addition of mineralization media to MLO-A5 seeded scaffolds triggered extensive formation of alizarin red-positive mineralized extracellular material, additional evidence of cell differentiation and completion of the final step of bone formation on the constructs. Collectively, the results indicate that the 13-93 glass fiber and trabecular scaffolds promote the attachment, growth, and differentiation of MLO-A5 osteogenic cells and could potentially be used for bone tissue engineering applications. PMID:22528984

  18. Tensile behavior and cyclic creep of continuous fiber-reinforced glass matrix composites at room and elevated temperatures

    NASA Astrophysics Data System (ADS)

    Boccaccini, A. R.; West, G.; Janczak, J.; Lewis, M. H.; Kern, H.

    1997-06-01

    In this study we investigated the stress-strain behavior at room and elevated temperatures and the tensile creep and cyclic creep response of a unidirectional SiC fiber-reinforced aluminosilicate glass matrix composite. The interfacial condition of the as-received material was measured by a push-out indentation technique. The stress-strain behavior was that expected for this kind of composite, i.e. “pseudoductile” behavior with extensive fiber “pull-out” at room temperature and brittle failure at intermediate temperatures (750 °C) due to oxidation embrittlement. The stiffness of the composite at 750°C was analyzed for different loading rates, highlighing the influence of the loading rate on apparent composite stiffness, due to matrix softening. The creep studies were conducted at temperatures above and below the softening temperature of the glass (T g, 745 °C) in air. The cyclic creep experiments showed the existence of extensive viscous strain recovery during the unloading period. The creep strain recovery was quantified using strain recovery ratios. These ratios showed a slight dependence on the temperatures investigated (700 and 750 °C). The crept composites retained their “graceful” fracture behavior only partially after testing, indicating that oxidation of the fiber/matrix interface due to oxygen diffusion through the matrix occurred in the peripheral area of the samples.

  19. Fracture resistance of tooth restored with four glass fiber post systems of varying surface geometries-An in vitro study

    PubMed Central

    Solomon-Sathish, Emmanuel; Venkatalakshmi-Aparna, Potluri; Balagopal, Sunderasan

    2016-01-01

    Background The purpose of this study was to relate the fracture resistance of endodontically treated teeth in relation to post geometry. Material and Methods Forty single rooted mandibular premolars were instrumented by step - back technique and obturated by lateral condensation. Forty teeth were randomly divided into four groups: Reforpost glass fiber X-ray®, RelyX®, Exacto conical® and Parapost Fiber Lux®. The post spaces were prepared using respective drills and luted. The core build up was done and metal crowns were luted. Fracture resistance was determined in universal testing machine. The statistical analysis was done using one way ANOVA and post hoc Tukey Kramer test. Results The teeth restored with Reforpost showed highest fracture resistance followed by Parapost and Exacto conical. The teeth restored with RelyX showed least fracture resistance. The teeth restored with Parapost had less unfavourable fracture followed by exacto conical. Conclusions Parallel design had less number of catastrophic failure and had better fracture resistance. Key words:Fracture resistance, glass fiber post, post geometry, stress. PMID:26855705

  20. Microscopic study of surface degradation of glass fiber-reinforced polymer rods embedded in concrete castings subjected to environmental conditioning

    SciTech Connect

    Bank, L.C.; Puterman, M.

    1997-12-31

    The surface degradation of glass fiber-reinforced polymer (GFRP) pultruded rods when embedded in concrete castings and subjected to environmental conditioning is discussed in this paper. Investigation of the degradation of the GFRP rods were performed using optical microscopy and scanning electron microscopy (SEM). Unidirectionally reinforced pultruded rods (6.3- and 12.7-mm diameters) containing E-glass fibers in polyester and vinylester matrices were conditioned at standard laboratory conditions (21 C, 65% relative humidity) or submerged in aqueous solutions (tap water) at 80 C for durations of 14 and 84 days. Observations of the surfaces and cross-sections of the rods by optical microscopy and SEM revealed a variety of degradation phenomena. Embedded hygrothermally conditioned rods were found to have developed surface blisters of different sizes and depths. SEM studies of the surface revealed degradation of the polymer matrix material and exposure and degradation of the fibers close to the surface of the rods. The rods with the vinylester resin matrix showed less extensive degradation than those with the polyester resin matrix; however, the degradation characteristics of the two types of rods appear to be similar.

  1. Bone plate composed of a ternary nano-hydroxyapatite/polyamide 66/glass fiber composite: biomechanical properties and biocompatibility.

    PubMed

    Qiao, Bo; Li, Jidong; Zhu, Qingmao; Guo, Shuquan; Qi, Xiaotong; Li, Weichao; Wu, Jun; Liu, Yang; Jiang, Dianming

    2014-01-01

    An ideal bone plate for internal fixation of bone fractures should have good biomechanical properties and biocompatibility. In this study, we prepared a new nondegradable bone plate composed of a ternary nano-hydroxyapatite/polyamide 66/glass fiber (n-HA/PA66/GF) composite. A breakage area on the n-HA/PA66/GF plate surface was characterized by scanning electron microscopy. Its mechanical properties were investigated using bone-plate constructs and biocompatibility was evaluated in vitro using bone marrow-derived mesenchymal stem cells. The results confirmed that adhesion between the n-HA/PA66 matrix and the glass fibers was strong, with only a few fibers pulled out at the site of breakage. Fractures fixed by the n-HA/PA66/GF plate showed lower stiffness and had satisfactory strength compared with rigid fixation using a titanium plate. Moreover, the results with regard to mesenchymal stem cell morphology, MTT assay, Alizarin Red S staining, enzyme-linked immunosorbent assay, and reverse transcription polymerase chain reaction for alkaline phosphatase and osteocalcin showed that the n-HA/PA66/GF composite was suitable for attachment and proliferation of mesenchymal stem cells, and did not have a negative influence on matrix mineralization or osteogenic differentiation of mesenchymal stem cells. These observations indicate that the n-HA/PA66/GF plate has good biomechanical properties and biocompatibility, and may be considered a new option for internal fixation in orthopedic surgery. PMID:24669191

  2. Effect of Reinforcement Using Stainless Steel Mesh, Glass Fibers, and Polyethylene on the Impact Strength of Heat Cure Denture Base Resin - An In Vitro Study

    PubMed Central

    Murthy, H B Mallikarjuna; Shaik, Sharaz; Sachdeva, Harleen; Khare, Sumit; Haralur, Satheesh B; Roopa, K T

    2015-01-01

    Background: The impact strength of denture base resin is of great concern and many approaches have been made to strengthen acrylic resin dentures. The objective of this study was to compare the impact strength of the denture base resin with and without reinforcement and to evaluate the impact strength of denture base resin when reinforced with stainless steel mesh, glass fiber, and polyethylene fibers in the woven form. Materials and Methods: The specimens (maxillary denture bases) were fabricated using a standard polyvinylsiloxane mold with conventional heat cured polymethyl methacrylate resin. The specimens were divided into four groups (n = 10). Group I specimens or control group were not reinforced. Group II specimens were reinforced with stainless steel mesh and Group III and Group IV specimens were reinforced with three percent by weight of glass fibers and polyethylene fibers in weave form respectively. All the specimens were immersed in water for 1-week before testing. The impact strength was measured with falling weight impact testing machine. One-way analysis of variance and Tukey’s post-hoc test were used for statistical analysis. Results: Highest impact strength values were exhibited by the specimens reinforced with polyethylene fibers followed by glass fibers, stainless steel mesh, and control group. Conclusions: Reinforcement of maxillary complete dentures showed a significant increase in impact strength when compared to unreinforced dentures. Polyethylene fibers exhibit better impact strength followed by glass fibers and stainless steel mesh. By using pre-impregnated glass and polyethylene fibers in woven form (prepregs) the impact strength of the denture bases can be increased effectively. PMID:26124604

  3. Comparison of selected optical properties of oxyfluoride glass fibers doped with Er3+ and co-doped with Er3+ Yb3+

    NASA Astrophysics Data System (ADS)

    Augustyn, E.; Stremplewski, P.; Rozanski, M.; Koepke, C.; Dominiak-Dzik, G.; Kępińska, M.; Żelechower, M.

    2011-12-01

    The method of manufacturing and spectroscopic evaluation of the Er3+ ions doped and Er3+-Yb3+co-doped SiO2-Al2O3-Na2CO3-CaO-PbO-PbF2 oxyfluoride glass fibers is presented in the paper. Both optically active elements erbium and ytterbium were introduced into the batch in the form of fluorides. The X-ray diffraction (XRD) technique was applied at each stage of fibers manufacturing in order to control an amorphous structure of the preforms and fibers. Optical studies of glass preforms and fibers (reflection/transmission, absorption, emission, and excited state absorption (ESA)) were directed to examine their suitability as fiber amplifiers at 1.55 μm band.

  4. Femtosecond laser processing of evanescence field coupled waveguides in single mode glass fibers for optical 3D shape sensing and navigation

    NASA Astrophysics Data System (ADS)

    Waltermann, Christian; Baumann, Anna Lena; Bethmann, Konrad; Doering, Alexander; Koch, Jan; Angelmahr, Martin; Schade, Wolfgang

    2015-05-01

    Fiber Bragg grating based optical shape sensing is a new and promising approach to gather position and path information in environments where classical imaging systems fail. Especially a real-time in-vivo navigation of medical catheter or endoscope without any further requirements (such as the continuous exposure to x-rays) could provide a huge advantage in countless areas in medicine. Multicore fibers or bundles of glass fibers have been suggested for realizing such shape sensors, but to date all suffer from severe disadvantages. We present the realization of a third approach. With femtosecond laser pulses local waveguides are inscribed into the cladding of a standard single mode glass fiber. The evanescence field of the main fiber core couples to two S-shaped waveguides, which carry the light to high reflective fiber Bragg gratings located approx. 30 μm away from the centered fiber core in an orthogonal configuration. Part of the reflected light is coupled back to the fiber core and can be read out by a fiber Bragg grating interrogator. A typical spectrum is presented as well as the sensor signal for bending in all directions and with different radii. The entire sensor plane has an elongation of less than 4 mm and therefore enables even complicated and localized navigation applications such as medical catheters. Finally a complete 3D shape sensor in a single mode fiber is presented together with an exemplary application for motion capturing.

  5. Glass-fiber-based neutron detectors for high- and low-flux environments

    NASA Astrophysics Data System (ADS)

    Bliss, Mary; Brodzinski, Ronald L.; Craig, Richard A.; Geelhood, Bruce D.; Knopf, Michael A.; Miley, Harry S.; Perkins, Richard W.; Reeder, Paul L.; Sunberg, Debra S.; Warner, Ray A.; Wogman, Ned A.

    1995-09-01

    Pacific Northwest Laboratory (PNL) has fabricated cerium-activated lithium silicate scintillating fibers via a hot-downdraw process. These fibers typically have a operational transmission length (e(superscript -1) length) of greater than 2 meters. This permits the fabrication of devices which were not possible to consider. Scintillating fibers permit conformable devices, large-area devices, and extremely small devices; in addition, as the thermal-neutron sensitive elements in a fast neutron detection system, scintillating fibers can be dispersed within moderator, improving neutron economy, over that possible with commercially available (superscript 3)He or BF(subscript 3) proportional counters. These fibers can be used for national-security applications, in medical applications, in the nuclear-power industry, and for personnel protection at experimental facilities. Data are presented for devices based on single fibers and devices made up of ribbons containing many fibers under high-and low-flux conditions.

  6. Homogeneity of bismuth-distribution in bismuth-doped alkali germanate laser glasses towards superbroad fiber amplifiers.

    PubMed

    Zhao, Yanqi; Wondraczek, Lothar; Mermet, Alain; Peng, Mingying; Zhang, Qinyuan; Qiu, Jianrong

    2015-05-01

    Compared to rare-earth doped glasses, bismuth-doped glasses hold promise for super-broadband near-infrared (NIR) photoemission and potential applications in optical amplification. However, optically active bismuth centers are extremely sensitive to the properties of the surrounding matrix, and also to processing conditions. This is strongly complicating the exploitation of this class of materials, because functional devices require a very delicate adjustment of the redox state of the bismuth species, and its distribution throughout the bulk of the material. It also largely limits some of the conventional processing routes for glass fiber, which start from gas phase deposition and may require very high processing temperature. Here, we investigate the influence of melting time and alkali addition on bismuth-related NIR photoluminescence from melt-derived germanate glasses. We show that the effect of melting time on bismuth-related absorption and NIR photoemission is primarily through bismuth volatilization. Adding alkali oxides as fluxing agents, the melt viscosity can be lowered to reduce either the glass melting temperature, or the melting time, or both. At the same time, however, alkali addition also leads to increasing mean-field basicity, what may reduce the intensity of bismuth-related NIR emission. Preferentially using Li2O over Na2O or K2O presents the best trade-off between those above factors, because its local effect may be adverse to the generally assumed trend of the negative influence of more basic matrix composition. This observation provides an important guideline for the design of melt-derived Bi-doped glasses with efficient NIR photoemission and high optical homogeneity. PMID:25969328

  7. Influence of antimicrobial solutions in the decontamination and adhesion of glass-fiber posts to root canals

    PubMed Central

    HARAGUSHIKU, Gisele Aihara; BACK, Eduardo Donato Eing Engelke; TOMAZINHO, Paulo Henrique; BARATTO, Flares; FURUSE, Adilson Yoshio

    2015-01-01

    Objective This study evaluated the effect of root canal disinfectants on the elimination of bacteria from the root canals, as well as their effect on glass-fiber posts bond strength. Material and Methods Fifty-three endodontically treated root canals had post spaces of 11 mm in length prepared and contaminated with E. faecalis. For CFU/ml analysis, eight teeth were contaminated for 1 h or 30 days (n=4). Teeth were decontaminated with 5% NaOCl, 2% CHX, or distilled water. As control, no decontamination was conducted. After decontamination, sterile paper points were used to collect samples, and CFU/ml were counted. For push-out, three groups were evaluated (n=15): irrigation with 2.5% NaOCl, 2% CHX, or sterile distilled water. A bonding agent was applied to root canal dentin, and a glass-fiber post was cemented with a dual-cured cement. After 24 h, 1-mm-thick slices of the middle portion of root canals were obtained and submitted to the push-out evaluation. Three specimens of each group were evaluated in scanning electron microscopy (SEM). Data were analyzed with one-way ANOVA and Dunnett’s T3 test (α=0.05). Results The number of CFU/ml increased from 1 h to 30 days of contamination in control and sterile distilled water groups. Decontamination with NaOCl was effective only when teeth were contaminated for 1 h. CHX was effective at both contamination times. NaOCl did not influence the bond strength (p>0.05). Higher values were observed with CHX (p<0.05). SEM showed formation of resin tags in all groups. Conclusion CHX showed better results for the irrigation of contaminated root canals both in reducing the bacterial contamination and in improving the glass-fiber post bonding. PMID:26398518

  8. Fracture Strength of Endodontically Treated Teeth Restored with Casting Post and Core and Glass-Fiber with Composite Core

    PubMed Central

    Saatian, Sedigheh

    2006-01-01

    INTRODUCTION: Prefabricated metal and ceramic posts can be used with different kinds of core materials as an alternative to the conventional casting post and cores. It is unclear how these post and core systems can withstand different kind of forces in the mouth. The purpose of this study was to compare the fracture strength of endodontically treated, crowned maxillary incisors restored with casting post and cores and glass- fiber post with composite core and to evaluate their mode of fractures. MATERIALS AND METHODS: Thirty caries free, human maxillary central incisors with incisoapical length of 23 ± 1 mm were divided into two groups. After root canal treatment procedures and decronation of teeth 2mm above cementoenamel junction, Grope 1 was restored with glass- fiber posts and composite cores and group 2 received casting post and cores. Teeth were prepared with a circumferential shoulder including a 1-2 mm ferrule and 0.5 mm bevel; all posts were cemented with an adhesive resin and teeth were restored with complete coverage crowns. Loads were applied at an angle of 135 degrees using a universal testing machine. Compression force was applied until the specimens fractured. RESULTS: The median fracture strengths of groups 1 and 2 were 459 and 686 respectively (p<0.5). In group I, all fractures occurred in incisal third of roots. In groups II, 40% of fractures were in apical third and middle of roots. CONCLUSION: Within the limitation of this study, the results suggested that glass fiber with composite cores can be used as an alternative to cast posts and cores in anterior teeth when creating 2mm ferrule effect was possible in normal occlusion. Clinical trial is required to verify these in vitro results. PMID:24470803

  9. A glass-coated tungsten microelectrode enclosing optical fibers for optogenetic exploration in primate deep brain structures.

    PubMed

    Tamura, Keita; Ohashi, Yohei; Tsubota, Tadashi; Takeuchi, Daigo; Hirabayashi, Toshiyuki; Yaguchi, Masae; Matsuyama, Makoto; Sekine, Takeru; Miyashita, Yasushi

    2012-10-15

    The optogenetic approach to primate brain circuitry has unparalleled potential for uncovering genetically and temporally resolved neuronal mechanisms of higher brain functions. In order to optogenetically investigate the large and complex primate brain, an optical-/electrical probe, or "optrode", must be inserted deeply, which requires the optrode to be not only long and stiff, but also sharp and smooth to reduce possible tissue damage. This study presents a tungsten microelectrode-based optrode that encloses optical fibers within its insulation glass. Optical fibers and a tungsten wire were tightly bound to each other and integrally coated with a smooth, thin layer of glass. This design satisfied the structural requirements for use in deep brain structures. The performance of the optrode was then examined in the thalamus of the rat and macaque monkeys which were injected with lentiviral vectors carrying the channelrhodopsin-2-enhanced yellow fluorescent protein (ChR2-EYFP) transgene. With fluorescence measurements via the optical fiber, ChR2-EYFP expression was detected clearly in vivo, which was confirmed by histological analysis in the rat. With photostimulation and extracellular recording, photo-responsive single-unit activities were isolated in the monkeys. The depth distribution of these units and the peak of the EYFP fluorescence profile overlapped consistently with each other. Thus, by developing a new probe, optogenetic methodology was successfully applied to a primate subcortical structure. This smooth glass-coated optrode is a promising tool for chronic in vivo experiments with various research targets including deep brain structures in behaving monkeys. PMID:22971353

  10. Accessory apartment conversion programs.

    PubMed

    Retsinas, J; Retsinas, N P

    1991-01-01

    In recent years, state housing finance agencies have joined with state units on aging to develop programs to help the frail, elderly homeowner. Under an accessory apartment conversion program, a low-income homeowner will borrow money at a reduced interest rate to underwrite conversion of excess space into a rental apartment. The tenant will provide additional income as well as, ideally, certain kinds of personal assistance and a friendly presence. To date, few elderly clients have used this option. The initial rationale for the program is explained as are plausible reasons for the fact that it has not met expectations. PMID:10186784

  11. Incorporation of Deoxyribonucleic Acid Precursors by T4 Deoxyribonucleic Acid-Protein Complexes Retained on Glass Fiber Filters

    PubMed Central

    Miller, Robert C.; Kozinski, Andrzej W.

    1970-01-01

    Bacteriophage T4 deoxyribonucleic acid (DNA)-protein complexes were retained preferentially on glass fiber filters. DNA polymerase activity in the complex was detected through the incorporation of 3H-labeled DNA precursors. The primer-product DNA hybridized with both phage and Escherichia coli DNA. Density labeling experiments showed that about 30% of incorporated 3H-deoxyadenosine triphosphate was found in DNA which hybridized with phage DNA; this DNA was found to be covalently attached to the primer DNA. PMID:5497903

  12. Sodium sulfate corrosion of silicon carbide fiber-reinforced calcium aluminosilicate glass-ceramic matrix composites. Master's thesis

    SciTech Connect

    Newton, P.J.

    1994-03-01

    Hot corrosion effects of Sodium Sulfate (NaSO4) coated Calcium Aluminosilicate (CAS)/Silicon Carbide (SiC) reinforced glass-ceramic matrix composite were investigated using Scanning Electron Microscopy (SEM), Energy Dispersive X-ray Analysis (EDX) and X-ray Diffraction (XRD). The samples provided by the Naval Air Warfare Center (NAWC) were unidirectional SiC/CAS as follows: (1) as received, (2) uncoated in air, (3) Na2SO4, coated in air and (4) Na2SO4 coated in argon. A heat treatment was conducted at 900 deg C for 100 hours. Experimental observations indicated that the Na2S04 coating in an oxidising environment had severely corroded the silicon fiber resulting in a silica rich, Nepheline, Wollastonite, Rankinite, Albite and glassy phases. In the argon atmosphere fiber degradation was present although less severe than in the oxygen environment. Similar phases of silica rich, Nepheline, Albite, Rankinite, Mullite, Pseudo-Wollastonite and a glassy region were present. Minimal fiber and matrix degradation was observed in the uncoated sample beat treated in air. Calcium aluminosilicate, SiC Fiber reinforced composites.

  13. Improvement of the mode II interface fracture toughness of glass fiber reinforced plastics/aluminum laminates through vapor grown carbon fiber interleaves

    NASA Astrophysics Data System (ADS)

    Ning, Huiming; Li, Yuan; Hu, Ning; Cao, Yanping; Yan, Cheng; Azuma, Takesi; Peng, Xianghe; Wu, Liangke; Li, Jinhua; Li, Leilei

    2014-06-01

    The effects of acid treatment, vapor grown carbon fiber (VGCF) interlayer and the angle, i.e., 0° and 90°, between the rolling stripes of an aluminum (Al) plate and the fiber direction of glass fiber reinforced plastics (GFRP) on the mode II interlaminar mechanical properties of GFRP/Al laminates were investigated. The experimental results of an end notched flexure test demonstrate that the acid treatment and the proper addition of VGCF can effectively improve the critical load and mode II fracture toughness of GFRP/Al laminates. The specimens with acid treatment and 10 g m-2 VGCF addition possess the highest mode II fracture toughness, i.e., 269% and 385% increases in the 0° and 90° specimens, respectively compared to those corresponding pristine ones. Due to the induced anisotropy by the rolling stripes on the aluminum plate, the 90° specimens possess 15.3%-73.6% higher mode II fracture toughness compared to the 0° specimens. The improvement mechanisms were explored by the observation of crack propagation path and fracture surface with optical, laser scanning and scanning electron microscopies. Moreover, finite element analyses were carried out based on the cohesive zone model to verify the experimental fracture toughness and to predict the interface shear strength between the aluminum plates and GFRP laminates.

  14. Health monitoring of precast bridge deck panels reinforced with glass fiber reinforced polymer bars

    NASA Astrophysics Data System (ADS)

    Ries, James Mcdaniel

    The Beaver Creek Bridge on US highway 6 is the pilot project for Glass Fiber Reinforced Polymer (GFRP) bridge decks and posttensioned bridge decks in the state of Utah. The bridge was built in 2009, using accelerated bridge construction practices, including the use of precast prestressed girders, as well as precast decking. The westbound bridge decking was composed of 12 precast panels each measuring 41'-5" long, 6'-10" wide, and 9¼" thick, and weighing approximately 33 kips. At the time, these panels were the longest GFRP panels in the United States. The Utah Department of Transportation has decided to evaluate GFRP reinforcing bars as an alternative to steel rebar in this bridge deck. The hope is to increase the lifespan of bridge decks to match the service life of the entire bridge. Due to the nature of the GFRP bars, the panels were lifted at four points using straps instead of imbedded anchors. During the four-point lifting, the panels exhibited small deflections and strains; furthermore, no cracks larger than hairline cracks were found in the panels after lifting. The Beaver Creek Bridge deck is the first precast deck in the state of Utah to be posttensioned in the direction of traffic. Posttensioning bridge decks is expected to become the norm in the state of Utah. The posttensioning resulted in increased continuity between panels. In order to quantify the expected performance of the bridge during its service life, a truck load test was performed. The truck load test was comprised of a static and dynamic test. During the truck load test, the bridge experienced deflections in the panels which were 93% below design values. Girder deflections were also small. The use of GFRP bars has the potential to extend the life of bridge decks exposed to deicing salts from 45 years to 100 years, while only requiring an increased capital cost in the bridge of 8%. Furthermore, the use of GFRP bars in conjunction with accelerated building practices has the potential to

  15. Joining of polypropylene/polypropylene and glass fiber reinforced polypropylene composites

    NASA Astrophysics Data System (ADS)

    Zhang, Jianguang

    Joining behavior of polypropylene (PP) to PP and long glass fiber reinforced polypropylene (LFT) to LFT were investigated. Adhesive bonding was used to join PP/PP. Both adhesive bonding and ultrasonic welding were used to join LFT/LFT. Single-lap shear testing and low velocity impact (LVI) testing were used to evaluate the performance of bonded structures. The two-part acrylic adhesive DP8005 was determined to be the best among the three adhesive candidates, which was attributed to its low surface energy. The impact resistance of LFT/LFT joints, normalized with respect to thickness, was higher than that of PP/PP joints because of higher stiffness of LFT/LFT joints. The stress states in the adhesive layer of adhesively bonded structures were analyzed using ANSYS and LS-DYNA to simulate the single-lap shear testing and LVI testing, respectively. The shear and peel stresses peaked at the edges of the adhesive layer. Compared to LFT/LFT joints, higher peel stress occurred in the adhesive layer in the PP/PP joints in tension. Impact response of adhesively bonded structures as evaluated by LS-DYNA showed good agreement with the experimental results. The effect of weld time and weld pressure on the shear strength of ultrasonically welded LFT/LFT was evaluated. With higher weld pressure, less time was required to obtain a complete weld. At longer weld times, lower weld pressure was required. From the 15 weld conditions studied, a weld map was obtained that provides conditions to achieve a complete weld. Nanoindentation was used to evaluate the effect of ultrasonic weld on the modulus and hardness of the PP matrix. Modulus and hardness of the PP matrix were slightly decreased by ultrasonic welding possibly due to the decrease in the molecular weight. The temperature profile in LFT/LFT in the transverse direction during ultrasonic welding was analyzed by two ANSYS-based thermal models: (a) one in which heat generated by interfacial friction was treated as a heat flux and (b

  16. Retrofit of hollow concrete masonry infilled steel frames using glass fiber reinforced plastic laminates

    NASA Astrophysics Data System (ADS)

    Hakam, Zeyad Hamed-Ramzy

    2000-11-01

    This study focuses on the retrofit of hollow concrete masonry infilled steel frames subjected to in-plane lateral loads using glass fiber reinforced plastic (GFRP) laminates that are epoxy-bonded to the exterior faces of the infill walls. An extensive experimental investigation using one-third scale modeling was conducted and consisted of two phases. In the first phase, 64 assemblages, half of which were retrofitted, were tested under various combined in-plane loading conditions similar to those which different regions of a typical infill wall are subjected to. In the second phase, one bare and four masonry-infilled steel frames representative of a typical single-story, single-bay panel were tested under diagonal loading to study the overall behavior and the infill-frame interaction. The relative infill-to-frame stiffness was varied as a test parameter by using two different steel frame sections. The laminates altered the failure modes of the masonry assemblages and reduced the variability and anisotropic nature of the masonry. For the prisms which failed due to shear and/or mortar joint slip, significant strength increases were observed. For those exhibiting compression failure modes, a marginal increase in strength resulted. Retrofitting the infilled frames resulted in an average increase in initial stiffness of two-fold compared to the unretrofitted infilled frames, and seemed independent of the relative infill-to-frame stiffness. However, the increase in the load-carrying capacity of the retrofitted frames compared to the unretrofitted counterparts was higher for those with the larger relative infill-to-frame stiffness parameter. Unlike the unretrofitted infill walls, the retrofitted panels demonstrated almost identical failure modes that were characterized as "strictly comer crushing" in the vicinity of the loaded comers whereas no signs of distress were evident throughout the remainder of the infill. The laminates also maintained the structural integrity of

  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. Single-ring hollow core optical fibers made by glass billet extrusion for Raman sensing.

    PubMed

    Tsiminis, G; Rowland, K J; Schartner, E P; Spooner, N A; Monro, T M; Ebendorff-Heidepriem, H

    2016-03-21

    We report the fabrication of the first extruded hollow core optical fiber with a single ring of cladding holes, and its use in a chemical sensing application. These single suspended ring structures show antiresonance reflection optical waveguiding (ARROW) features in the visible part of the spectrum. The impact of preform pressurization on the geometry of these fibers is determined by the size of the different hole types in the preform. The fibers are used to perform Raman sensing of methanol, demonstrating their potential for future fiber sensing applications. PMID:27136787

  19. Tensile properties and translaminar fracture toughness of glass fiber reinforced unsaturated polyester resin composites aged in distilled and salt water

    NASA Astrophysics Data System (ADS)

    Sugiman, Gozali, M. Hulaifi; Setyawan, Paryanto Dwi

    2016-03-01

    Glass fiber reinforced polymer has been widely used in chemical industry and transportation due to lightweight and cost effective manufacturing. However due to the ability to absorb water from the environment, the durability issue is of interest for up to days. This paper investigated the water uptake and the effect of absorbed water on the tensile properties and the translaminar fracture toughness of glass fiber reinforced unsaturated polyester composites (GFRP) aged in distilled and salt water up to 30 days at a temperature of 50°C. It has been shown that GFRP absorbed more water in distilled water than in salt water. In distilled water, the tensile strength of GFRP tends to decrease steeply at 7 days and then slightly recovered for further immersion time. In salt water, the tensile strength tends to decrease continually up to 30 days immersion. The translaminar fracture toughness of GFRP aged in both distilled and salt-water shows the similar behavior. The translaminar fracture toughness increases after 7 days immersion and then tends to decrease beyond that immersion time. In the existence of ionics content in salt water, it causes more detrimental effect on the mechanical properties of fiberglass/unsaturated polyester composites compared to that of distilled water.

  20. Er(3)/Yb(3)-codoped phosphate glass for short-length high-gain fiber lasers and amplifiers.

    PubMed

    Wang, Fengxiao; Song, Feng; An, Shuangxin; Wan, Wenshun; Guo, Hao; Liu, Shujing; Tian, Jianguo

    2015-02-10

    Er(3)/Yb(3)-codoped phosphate glass with compositions of (78.2-x)P(2)O(5)-14Al(2)O(3)-5Li(2)O-1K(2)O-1.8Yb(2)O(3)-xEr(2)O(3)(x=0.2,0.4,0.6) in mol. % were investigated. Judd-Ofelt (JO) intensity parameters have been calculated to predict radiative properties based on absorption spectra. The stimulated emission cross section (σ(e)) calculated according to McCumber theory was 1.50×10(-20)  cm(2), almost twice larger than values reported before. The effective line width (Δ(eff)), full width at half-maximum (FWHM) and the quality parameters for designing optical amplifier devices were listed in the table compared with other types of phosphate glass matrices. A theoretical model of a Er(3)/Yb(3)-codoped system based on rate and power propagation equations was put forward to investigate the potential advantages of the materials applied for short-length, high-gain fiber amplifiers. A simulated gain of 32.2 and 2.6  dB/cm per unit length was achieved in 12.5-cm-long fiber. PMID:25968040

  1. Particle size, size distribution and morphological evaluation of glass fiber reinforced plastic (GRP) industrial by-product.

    PubMed

    Mazzoli, Alida; Moriconi, Giacomo

    2014-12-01

    The waste management of glass fiber reinforced polymer (GRP) materials, in particular those made with thermosetting resins, is a critical issue for the composites industry because these materials cannot be reprocessed. Therefore, most thermosetting GRP waste is presently sent to landfill, in spite of the significant environmental impact caused by their disposal in this way. The limited GRP waste recycling worldwide is mostly due to its intrinsic thermosetting properties, lack of characterization data and unavailability of viable recycling and recovery routes. One of the possibility for re-using GRP industrial by-product is in form of powder as a partial aggregate replacement or filler addition in cement based composites for applications in sustainable construction materials and technologies. However, the feasibility of this kind of reutilization strongly depends on the morphology and particle size distribution of a powder made up of polymer granules and glass fibers. In the present study, the use of image analysis method, based on scanning electron microscopy (SEM) and ImageJ processing program, is proposed in order to evaluate the morphology of the particles and measure the particle size and size distribution of fine GRP waste powder. The obtained results show a great potential of such a method in order to be considered as a standardized method of measurement and analysis in order to characterize the grain size and size distribution of GRP particles before exploiting any compatibility issue for its recycling management. PMID:25195092

  2. Recovery of phosphonate surface contaminants from glass using a simple vacuum extractor with a solid-phase microextraction fiber

    SciTech Connect

    Gary S. Groenewold; Jill R. Scott; Cathy Rae

    2011-07-01

    Recovery of chemical contaminants from fixed surfaces for analysis can be challenging particularly if it is not possible to acquire a solid sample. A simple device is described that collects semivolatile organic compounds from fixed surfaces by creating an enclosed volume over the surface, then generating a modest vacuum. A solid-phase microextraction fiber is then inserted into the evacuated volume where it functions to sorb volatilized organic contaminants. The device is based on a syringe modified with a seal that is used to create the vacuum, with a perforable plunger through which the SPME fiber is inserted. The vacuum speeds partitioning of the semivolatile compounds into the gas phase, and reduces the boundary layer around the SPME fiber, which enables a fraction of the volatilized organics to partition into the SPME fiber. After sample collection the SPME fiber is analyzed using conventional gas chromatography/mass spectrometry. The methodology has been used to collect organophosphorus compounds from glass surfaces, to provide a simple test for the functionality of the devices. Thirty minute sampling times (deltaTvac) resulted in fractional recovery efficiencies ranged from 10(-3) to > 10(-1), and in absolute terms collection of low nanograms was demonstrated. Fractional recovery values were correlated to the vapor pressure of the compounds being sampled. Fractional recovery increased with increasing deltaTvac, and displayed a roughly logarithmic profile indicating that an operational equilibrium is being approached. Fractional recovery decreased with increasing time between exposure and sampling, however recordable quantities of the phosphonates could be collected three weeks after exposure.

  3. Thermal energy harvesting for large-scale applications using MWCNT-grafted glass fibers and polycarbonate-MWCNT nanocomposites

    NASA Astrophysics Data System (ADS)

    Tzounis, L.; Liebscher, M.; Mäder, E.; Pötschke, P.; Stamm, M.; Logothetidis, S.

    2015-02-01

    The thermoelectric properties of multi-wall carbon nanotube (MWCNT) -grafted glass fiber yarns (GF-CNT) and their epoxy model composites, as well as of polymer nanocomposites consisting of a polycarbonate (PC) matrix filled with differently functionalized MWCNTs have been examined. The GF-CNT hierarchical multi-scale structures were prepared by dip coating glass fiber yarns in a solution of carbonyl chloride modified MWCNTs; MWCNT-COCl (at a concentration of 0.5 mg/ml) under Ar atmosphere. The resulting GF-CNT exhibited high electrical conductivity (σ= 2.1×103 S/m) due to the dense MWCNT deposited networks. The fiber surface morphology was investigated by scanning electron microscopy (SEM). The GF-CNT showed Seebeck coefficient (S); S = 16.8 μV/K, and power factor (P.F); P.F = 0.59 μW/mK-2. The high electrical conductivity of the GF-CNT is a key parameter for an optimum thermoelectric performance, since it can facilitate the flow of the thermally induced charge carriers upon being exposed to a temperature gradient. Polycarbonate/MWCNT nanocomposites were prepared by small-scale melt-mixing process using a microcompounder. Unfunctionalized, carboxyl (-COOH) and hydroxyl (-OH) modified MWCNTs were incorporated in PC at a constant amount of 2.5 wt.%, concentration above the electrical percolation threshold. The amount of MWCNTs was kept low to understand the fundamental aspects of their physical properties and their correlation to the composite morphology, as revealed by transmission electron microscopy (TEM). It was found that different functional groups can affect the thermoelectric performance and the conductivity of the nanocomposites. Namely, the highest Seebeck coefficient (S) was found for the composite containing carboxyl functionalized MWCNTs (11.3 μV/K), due to the highest oxygen content of MWCNTs proven by X-Ray Photoelectron spectroscopy (XPS). It is believed that MWCNT-grafted glass fibers as reinforcements in composite structural materials and PC

  4. Thermal energy harvesting for large-scale applications using MWCNT-grafted glass fibers and polycarbonate-MWCNT nanocomposites

    SciTech Connect

    Tzounis, L.; Liebscher, M.; Stamm, M.; Mäder, E.; Pötschke, P.; Logothetidis, S.

    2015-02-17

    The thermoelectric properties of multi-wall carbon nanotube (MWCNT) -grafted glass fiber yarns (GF-CNT) and their epoxy model composites, as well as of polymer nanocomposites consisting of a polycarbonate (PC) matrix filled with differently functionalized MWCNTs have been examined. The GF-CNT hierarchical multi-scale structures were prepared by dip coating glass fiber yarns in a solution of carbonyl chloride modified MWCNTs; MWCNT-COCl (at a concentration of 0.5 mg/ml) under Ar atmosphere. The resulting GF-CNT exhibited high electrical conductivity (σ = 2.1×10{sup 3} S/m) due to the dense MWCNT deposited networks. The fiber surface morphology was investigated by scanning electron microscopy (SEM). The GF-CNT showed Seebeck coefficient (S); S = 16.8 μV/K, and power factor (P.F); P.F = 0.59 μW/mK−2. The high electrical conductivity of the GF-CNT is a key parameter for an optimum thermoelectric performance, since it can facilitate the flow of the thermally induced charge carriers upon being exposed to a temperature gradient. Polycarbonate/MWCNT nanocomposites were prepared by small-scale melt-mixing process using a microcompounder. Unfunctionalized, carboxyl (-COOH) and hydroxyl (-OH) modified MWCNTs were incorporated in PC at a constant amount of 2.5 wt.%, concentration above the electrical percolation threshold. The amount of MWCNTs was kept low to understand the fundamental aspects of their physical properties and their correlation to the composite morphology, as revealed by transmission electron microscopy (TEM). It was found that different functional groups can affect the thermoelectric performance and the conductivity of the nanocomposites. Namely, the highest Seebeck coefficient (S) was found for the composite containing carboxyl functionalized MWCNTs (11.3 μV/K), due to the highest oxygen content of MWCNTs proven by X-Ray Photoelectron spectroscopy (XPS). It is believed that MWCNT-grafted glass fibers as reinforcements in composite structural

  5. An In Vitro Comparative Evaluation of Fracture Resistance of Custom Made, Metal, Glass Fiber Reinforced and Carbon Reinforced Posts in Endodontically Treated Teeth

    PubMed Central

    Sonkesriya, Subhash; Olekar, Santosh T; Saravanan, V; Somasunderam, P; Chauhan, Rashmi Singh; Chaurasia, Vishwajit Rampratap

    2015-01-01

    Background: Posts are used to enhance crown buildup in pulpless teeth with destructed crown portion. Different types of post are used in endodontically treated teeth. The aim of the present in vitro study was to evaluate fracture resistance of custom made, metal, glass fiber reinforced and carbon reinforced posts in endodontically treated teeth. Materials and Methods: An in vitro study was carried out on extracted 40 human maxillary central incisor teeth, which was divided into four groups with 10 samples in each group with custom made, metal post, glass fiber reinforced, and carbon reinforced posts. The samples were decoronated at cemento-enamel junction and endodontically treated. Post space was prepared and selected posts were cemented. The composite cores were prepared at the height of 5 mm and samples mounted on acrylic blocks. Later fracture resistance to the compressive force of samples was measured using Universal Testing Machine. Results: The maximum resistance to the compressive force was observed in carbon reinforced and glass fiber reinforced posts compared others which is statistically significant (P > 0.001) and least was seen in custom fabricated post. Conclusion: It is concluded that carbon reinforced fiber post and glass fiber posts showed good fracture resistance compared to custom made and metal posts. PMID:26028904

  6. The use of an experimental room for monitoring of airborne concentrations of microorganisms, glass fibers, and total particles

    SciTech Connect

    Buttner, M.P.; Stetzenbach, L.D.

    1996-12-31

    An experimental room was used as a microcosm for studies of airborne particles and microorganisms in indoor environments. The interior of the room measures 4 by 4 by 2.2 m high and has a hardwood floor and the walls and ceiling are sheetrocked and coated with interior latex paint. Exterior walls are 11.4-cm thick plywood panels consisting of two outer sections of plywood insulated with fiber glass batts. The ceiling is of similar construction with 17.1-cm thick panels. Attached to the room entrance is an anteroom equipped with a HEPA-filtered air shower to reduce mixing of air resulting from entering and exiting during experiments. The room is equipped with a computer-controlled heating, ventilation, and cooling system. Temperature, relative humidity, air flow, and room pressure can be continuously monitored by probes located in the room and air handling system components. Several research projects have been conducted using this room including monitoring the potential for airborne glass fibers released from rigid fibrous ductboard, comparisons of commercially available samplers for monitoring of airborne fungal spores, and a study on the efficacy of vacuum bags to minimize dispersal of particles, including fungal spores from fungal-contaminated carpet. During studies designed to monitor airborne fiberglass, air samples were taken in the room serviced by new rigid fibrous glass ductwork, and the results were compared to those obtained in the room with bare metal ductwork installed. Monitoring of airborne fungal spores using the Andersen six-stage sampler, the high flow Spiral Biotech sampler, the Biotest RCS Plus sampler, and the Burkard spore trap sampler was performed following the release of Penicillium spores into the room through the supply register. Dispersal of carpet-associated particles and fungal spores was measured after vacuuming using conventional cellulose vacuum bags in comparison to recently developed bags.

  7. The photosensitivity of ytterbium-doped optical fibers with aluminophosphosilicate glass cores

    NASA Astrophysics Data System (ADS)

    Rybaltovsky, A. A.; Butov, O. V.; Savel'ev, E. A.; Chamorovskii, Yu. K.

    2016-05-01

    The phenomenon of photoinduced refractive index change in active optical fibers with Al2O3/P2O5/Yb2O3/SiO2 core composition has been observed under the action of UV laser radiation with 193-nm wavelength. It is established that hydrogen treatment of active fibers plays a key role in ensuring a radical (about two orders of magnitude) increase in their photosensitivity. It is shown that intrafiber Bragg gratings with reflection coefficients above 99% can be formed, which are promising mirror reflectors for fiber laser cavities.

  8. Notch-sensitive fracture behavior of a silicon carbide fiber-reinforced glass-ceramic at elevated temperatures

    SciTech Connect

    Kahraman, R.; Sunar, M.

    1998-02-01

    The effect on high-temperature embrittlement of introducing a through-thickness notch in a multidirectional silicon carbide fiber-reinforced calcium-aluminosilicate glass-ceramic composite was investigated through tensile testing, microdebonding, and light and scanning electron microscopy techniques. The fracture mechanism of the composite changed from notch insensitive at room temperature to notch sensitive at elevated temperatures due to increased fiber-matrix bond strength caused by oxidation effects at interfaces exposed to the oxidative environment. Stress concentration and bending effects at the notch tip resulted in growth of the notch through fibers in a planar fashion covering the entire fracture surface. This was contrary to the case of an unnotched composite, for which two distinct fracture surface regions were observed as planar embrittlement zones at the periphery and fibrous at the center. Cracks in the notched composite were more closed relative to those in the unnotched one, except at the notch tip. Concentration of the stress at the notch tip increased the high-temperature embrittlement effect on the composite.

  9. Immediate and delayed photoactivation of self-adhesive resin cements and retention of glass-fiber posts.

    PubMed

    Faria-e-Silva, André Luis; Peixoto, Aline Carvalho; Borges, Marcela Gonçalves; Menezes, Murilo de Sousa; Moraes, Rafael Ratto de

    2014-01-01

    The aim of this study was to evaluate the effect of immediate and delayed photoactivation of self-adhesive resin cements (SARCs) on the retention of glass-fiber posts luted into root canals. Bovine incisors were endodontically treated, and post holes of 9 mm in depth were prepared. Fiber posts were luted using one of two SARCs, BisCem (Bisco Inc., Schaumburg, USA) or RelyX Unicem clicker (3M ESPE, Saint Paul, USA), or a regular (etch-and-rinse) resin cement (AllCem; FGM, Joinvile, Brazil). Photoactivation was performed immediately, or at 5 or 10 min after cementation. Root/post specimens were transversely sectioned 7 days after luting into 1-mm-thick slices, which were submitted to push-out testing in a mechanical testing machine. Bond strength data were analyzed by two-way ANOVA and Student-Newman-Keuls' method (α = 0.05). Immediate photoactivation resulted in the highest bond strength for Unicem. BisCem demonstrated higher bond strength values when photoactivated after a 10-min delay. Immediate photoactivation yielded the lowest bond strengths for AllCem, although no differences in bond strength were observed between photoactivation delayed by 5 and 10 min. In conclusion, the moment of resin cement photoactivation may affect the intraradicular retention of fiber posts, depending upon the resin cement used for luting. PMID:25006624

  10. Intermediate-temperature environmental effects on boron nitride-coated silicon carbide-fiber-reinforced glass-ceramic composites

    SciTech Connect

    Sun, E.Y.; Lin, H.T.; Brennan, J.J.

    1997-03-01

    The environmental effects on the mechanical properties of fiber-reinforced composites at intermediate temperatures were investigated by conducting flexural static-fatigue experiments in air at 600 and 950 C. The material that was studied was a silicon carbide/boron nitride (SiC/BN) dual-coated Nicalon-fiber-reinforced barium magnesium aluminosilicate glass-ceramic. Comparable time-dependent failure responses were found at 600 and 950 C when the maximum tensile stress applied in the bend bar was >60% of the room-temperature ultimate flexural strength of as-received materials. At both temperatures, the materials survived 500 h fatigue tests at lower stress levels. Among the samples that survived the 500 h fatigue tests, a 20% degradation in the room temperature flexural strength was measured in samples that were fatigued at 600 C. The growth rate of the Si-C-O fiber oxidation product at 600 C was not sufficient to seal the stress-induced cracks, so that the interior of the material was oxidized and resulted in a strength degradation and less fibrous fracture. In contrast, the interior of the material remained intact at 950 C because of crack sealing by rapid silicate formation, and strength/toughness of the composite was maintained. Also, at 600 C, BN oxidized via volatilization, because no borosilicate was formed.

  11. High-Q Hybrid Plasmon-Photon Modes in a Bottle Resonator Realized with a Silver-Coated Glass Fiber with a Varying Diameter

    NASA Astrophysics Data System (ADS)

    Rottler, Andreas; Harland, Malte; Bröll, Markus; Klingbeil, Matthias; Ehlermann, Jens; Mendach, Stefan

    2013-12-01

    We experimentally demonstrate that hybrid plasmon-photon modes exist in a silver-coated glass bottle resonator. The bottle resonator is realized in a glass fiber with a smoothly varying diameter, which is subsequently coated with a rhodamine 800-dye doped acryl-glass layer and a 30 nm thick silver layer. We show by means of photoluminescence experiments supported by electromagnetic simulations that the rhodamine 800 photoluminescence excites hybrid plasmon-photon modes in such a bottle resonator, which provide a plasmon-type field enhancement at the outer silver surface and exhibit quality factors as high as 1000.

  12. High-Q hybrid plasmon-photon modes in a bottle resonator realized with a silver-coated glass fiber with a varying diameter.

    PubMed

    Rottler, Andreas; Harland, Malte; Bröll, Markus; Klingbeil, Matthias; Ehlermann, Jens; Mendach, Stefan

    2013-12-20

    We experimentally demonstrate that hybrid plasmon-photon modes exist in a silver-coated glass bottle resonator. The bottle resonator is realized in a glass fiber with a smoothly varying diameter, which is subsequently coated with a rhodamine 800-dye doped acryl-glass layer and a 30 nm thick silver layer. We show by means of photoluminescence experiments supported by electromagnetic simulations that the rhodamine 800 photoluminescence excites hybrid plasmon-photon modes in such a bottle resonator, which provide a plasmon-type field enhancement at the outer silver surface and exhibit quality factors as high as 1000. PMID:24483745

  13. Ultra-broadband modulation instability gain characteristics in As2S3 and As2Se3 chalcogenide glass photonic crystal fiber

    NASA Astrophysics Data System (ADS)

    He-Lin, Wang; Bin, Wu; Xiao-Long, Wang

    2016-06-01

    Based on the designed As2Se3 and As2S3 chalcogenide glass photonic crystal fiber (PCF) and the scalar nonlinear Schrödinger equation, the effects of pump power and wavelength on modulation instability (MI) gain are comprehensively studied in the abnormal dispersion regime of chalcogenide glass PCF. Owing to high Raman effect and high nonlinearity, ultra-broadband MI gain is obtained in chalcogenide glass PCF. By choosing the appropriate pump parameter, the MI gain bandwidth reaches 2738 nm for the As2Se3 glass PCF in the abnormal-dispersion region, while it is 1961 nm for the As2S3 glass PCF. Project supported by the National Natural Science Fundation of China (Grant No. 11404286), the Natural Science Fundation of Zhejiang Province, China (Grant No. LY15F050010), and the Scientific Research Foundation of Zhejiang University of Technology, China (Grant No. 1401109012408).

  14. Prototype high detective quantum efficiency imaging panel based on a fiber-optic scintillation glass array (FOSGA) for megavoltage imaging

    NASA Astrophysics Data System (ADS)

    Samant, Sanjiv; Baciak, Jim; Gopal, Arun

    2011-09-01

    Megavoltage imaging has applications in nondestructive imaging for homeland security, radiotherapy, and industrial manufacturing. Current commercial systems are limited by low image quality as measured by detective quantum efficiency (DQE). These systems yield measured DQE=0.01-0.02, limiting efficacy for detection based on automated signal processing. Past efforts to improve DQE have included novel scintillators and manufacturing of large crystal structures. An alternative novel design for a 2D x-ray imager, based on a modification of existing amorphous silicon (a:Si) or flat-panel imagers, is presented. The panel utilizes a fiber-optic scintillation glass array (FOSGA) consisting of scintillation fibers bundled within a pixilated thick sintered tungsten housing. The tungsten housing is constructed using a lithographic manufacturing technique for high fabrication accuracy. The Tb-doped fibers emit light in the 555-565nm range (matched to the sensitive region of current a:Si photodiodes), with a decay time of 2ms (100-to-40%). Monte Carlo simulations, linear cascaded systems analyses, and film studies have been carried out to validate and optimize image quality for radiation beams in the 1-6MV range. An 8cmx8cm prototype array was fabricated using Tb-doped fibers (9mm length, 0.9mm diameter) loaded into a tungsten matrix (1.1mm pixel pitch, 0.1mm septa), yielding measured DQE=0.05 (vs theoretical DQE=0.07) for 6MV imaging , an order of magnitude improvement in image quality over current commercial imagers. Design parameters of a large field-of-view FOSGA imager for cargo container security imaging are presented: 5cm thick FOSGA array, 0.4-1mm pixel pitch, 50-70% fill factor, DQE>0.2 for 1-6MV range.

  15. Material Characterization of Glass, Carbon, and Hybrid-Fiber SCRIMP Panels

    SciTech Connect

    KURAISHI, AKIRA; TSAI, STEPHEN W.; WANG, JULIE

    2002-12-01

    The purpose of this study was to generate the material database for carbon and glass composite panels created by the SCRIMP process. The materials tested were glass/polyester composites, two types of carbon/polyester composites, and carbon and glass hybrid composites. The differences between the two types of carbon/polyester, which we call Type 1 and Type 2, are the ply thickness (.037 inch/ply and .048 inch/ply) and slightly different treatment of polyester resin. The tests that were performed for this study are four-point-bending tests, tension tests, panel warping tests, and beam bend-twist coupling tests. The material properties of interest were basic longitudinal and transverse stiffness and strength, residual stress due to curing, and the effect of bend-twist coupling. The bend-twist coupling is a feature that can be added to the composite laminate or structure, such that when it is bent, it will also twist.

  16. Spectroscopic determination of the in-situ composition of epoxy matrices in glass fiber reinforced composites

    NASA Technical Reports Server (NTRS)

    Antoon, M. K.; Zehner, B. E.; Koenig, J. L.

    1980-01-01

    Computerized infrared analysis is applied to the characterization of a glass-reinforced crosslinked polyester. The method of factor analysis determines the number of independent components which constitute the polymeric matrix. Subsequently, the spectra of those components are fitted by a least-squares criterion to spectra of the multicomponent matrix, or, if the glass spectrum is included as an additional component, to the spectra of composites. The least-squares coefficients yield the matrix composition in terms of the initial reactant composition and the extent of crosslinking.

  17. An Undergraduate Laboratory Experiment that Utilizes a Glass Fiber Filter Assay to Determine the Steroid Specificity and Equilibrium Binding Properties of Glucocorticoid Receptors.

    ERIC Educational Resources Information Center

    John, Nancy J.; Firestone, Gary L.

    1987-01-01

    Describes two complementary laboratory exercises that use the glass fiber assay to assess receptor specificity and hormone binding affinity in rat liver cytoplasmic extracts. Details the methods, materials and protocol of the experiments. Discusses the basic concepts illustrated and the feasibility of using the experiments at the undergraduate…

  18. Dynamic mechanical analysis and high strain-rate energy absorption characteristics of vertically aligned carbon nanotube reinforced woven fiber-glass composites

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The dynamic mechanical behavior and energy absorption characteristics of nano-enhanced functionally graded composites, consisting of 3 layers of vertically aligned carbon nanotube (VACNT) forests grown on woven fiber-glass (FG) layer and embedded within 10 layers of woven FG, with polyester (PE) and...

  19. Fiber orientation structures and mechanical properties of injection molded short glass fiber-reinforced nylon ribbed plates

    SciTech Connect

    Wire, S.L.; Hine, P.J.; Duckett, R.A.; O`Gara, J.G.

    1996-12-31

    The work presented in this paper, sponsored by General Motors, describes a study of injection moulded ribbed plates of short glass fibre-reinforced Nylon. Ribs have been placed both parallel and perpendicular to the injection direction in an attempt to simulate the likely geometry of an actual automotive part. The complex orientation structures developed within these ribbed samples during injection moulding have been determined within both the parallel and perpendicular ribs, and for the regions between these structures using an automated image analysis system developed in-house by our colleagues at the University of Leeds Instrumentation Group. This system allows the rapid measurement of accurate fibre orientation data over large sample areas (mm {times} mm) enabling thousands of fibre images to be sampled. Mechanical properties both between and underneath the rib structures have been measured using the ultrasonic immersion technique, and these have been compared with theoretical predictions, determined using the measured fibre orientation averages and simple composite models developed within this laboratory. In general the agreement between theory and experiment is excellent.

  20. Enhanced sensitivity of Raman spectroscopy for tritium gas analysis using a metal-lined hollow glass fiber

    SciTech Connect

    Rupp, S.; Schloesser, M.; Bornschein, B.; James, T.M.; Telle, H.H.

    2015-03-15

    The precise compositional analysis of tritium-containing gases is of high interest for tritium accountancy in future fusion power plants. Raman spectroscopy provides a fast and contact-free gas analysis procedure with high precision, thus being an advantageous tool for the named purpose. In this paper, it is shown that the sensitivity achieved with conventional Raman systems (in 90 degrees or forward/backward configurations) can be enhanced by at least one order of magnitude by using a metal-lined hollow glass fiber as the Raman cell. This leads to the ability of detecting low partial pressures of tritium within short measurement intervals (< 0.5 mbar in < 0.5 s) opening the way for real-time applications.

  1. Short all Tm-doped germanate glass fiber MOPA single-frequency laser at 1.95 μm.

    PubMed

    Yang, Changsheng; Chen, Dan; Xu, Shanhui; Deng, Huaqiu; Lin, Wei; Zhao, Qilai; Zhang, Yuanfei; Zhou, Kaijun; Feng, Zhouming; Qian, Qi; Yang, Zhongmin

    2016-05-16

    Based on heavily Tm-doped germanate glass fibers (TGFs), a short all-TGF MOPA laser system with uniform core parameters in each stage was demonstrated. An 11.7 W stable single-frequency laser at 1.95 μm with an optical-to-optical conversion efficiency of 20.4% is obtained from a homemade 31-cm-long double-cladding single-mode TGF. The estimated stimulated Brillouin scattering (SBS) threshold of 980 W and the measured relative intensity noise of < -130 dB/Hz for frequencies above 2 MHz are achieved in this MOPA system. Furthermore, the prospect for further power-scaling of such short MOPA laser is considered. PMID:27409917

  2. The effect of electron beam irradiation on properties of virgin and glass fiber-reinforced polyamide 6

    NASA Astrophysics Data System (ADS)

    Porubská, Mária; Janigová, Ivica; Jomová, Klaudia; Chodák, Ivan

    2014-09-01

    Crosslinking of virgin polyamide 6 (PA-6) and PA-6 filled with 30 wt% glass fibers (GF) was investigated. The crosslinking was initiated by electron irradiation applying dose ranging from 50 to 500 kGy. The gel point was determined to be 200 kGy for both materials. The results obtained indicate that the GF presence may retard gel formation in the PA-matrix. The irradiation of unfilled PA-6 resulted in an increase in tensile strength at break and Young's moduli (a minimum 50% gel content is needed), tensile properties at yield were not affected by crosslinking. Thermal resistance, as measured by the heat deflection temperature and Vicat softening temperature, was affected only marginally. Considering these effects, electron beam irradiation is found to be more beneficial for the virgin PA than for the corresponding PA/GF composite.

  3. Application of fiber grating-based acoustic sensor in progressive failure testing of e-glass/vinylester curve composites

    NASA Astrophysics Data System (ADS)

    Azmi, Asrul Izam; Raju, Raju; Peng, Gang-Ding

    2012-02-01

    This paper reports an application of phase shifted fiber Bragg grating (PS-FBG) intensity-type acoustic sensor in a continuous and in-situ failure testing of an E-glass/vinylester top hat stiffener (THS). The narrow transmission channel of the PS-FBG is highly sensitive to small perturbation, hence suitable to be used in an effective acoustic emission (AE) assessment technique. The progressive failure of THS was tested under transverse loading to experimentally simulate the actual loading in practice. Our experimental tests have demonstrated, in good agreement with the commercial piezoelectric sensors, that the important failures information of the THS was successfully recorded by the simple intensity-type PS-FBG sensor.

  4. Study of a membrane bioreactor with glass fiber flat grille modules and the modules' optimization based on the local critical flux theory.

    PubMed

    Yuan, Dongdong; Fan, Yaobo; Yu, Yan; Xu, Guoliang; Yang, Wenjing; Wu, Guangxia

    2010-02-01

    A novel flat grille membrane module using inorganic glass fibers as filter media is proposed for use in a membrane bioreactor for wastewater treatment. A model which integrates the concepts of back transport velocity, spatial local critical flux and temporal variation of the local flux has been developed. The membrane module was optimized based on experimental results and calculations using the model. The optimized parameters include the volume ratio of membrane solution for the surface modification of glass fibers, the fiber inner diameter and fiber length. The optimal values were 1:2 and 5mm respectively but the length had little effect on the performance of the module. The critical time was then calculated with the model and an equation developed. The result was in very good agreement with the observed one. Finally, the performance of the glass fiber MBR was monitored. The effluent quality and stability of the system were comparable to that of conventional MBRs. This MBR will be a promising technique for wastewater treatment given its low cost, high strength and good effluent quality. PMID:19913276

  5. Generation of broadband mid-infrared supercontinuum radiation in cascaded soft-glass fibers

    NASA Astrophysics Data System (ADS)

    Kneis, C.; Robin, T.; Cadier, B.; Brilland, Laurent; Caillaud, Celine; Troles, Johann; Manek-Hönninger, I.; Eichhorn, M.; Kieleck, C.

    2016-03-01

    The generation of mid-infrared (mid-IR) radiation, ranging from 2 - 5 μm, is getting much attention in recent years thanks to many applications it can be used for, e.g. in free space optical communication, range finding, counter measures and remote chemical sensing systems. It also plays an increasing role in medicine, for instance in optical tissue ablation or optical coherence tomography, owing to the high water absorption in that wavelength range. In this research study, a ZrF4-BaF2-LaF3-AlF3-NaF (ZBLAN) fluoride fiber is pumped by a Q-switched mode-locked (QML) thulium (Tm3+)- doped double-clad silica fiber laser, emitting at around 2 μm, to generate mid-IR supercontinuum (SC). Further spectral broadening of this SC radiation is achieved by coupling it into a chalcogenide arsenide-selenide (AsSe) photonic crystal fiber (PCF). An output power of 24 W at 2 μm has been achieved in QML operation for the Tm3+-doped fiber laser. The SC output power from the ZBLAN fiber has been 7.8 W with a spectrum extending to approximately 4.1 μm. For further wavelength broadening experiments, a long-wave-pass filter with a 3 dB edge around 3.6 μm has been implemented between the ZBLAN and the AsSe fiber to cut out the residual pump light at 2 μm and the radiation between 2 μm and 3.5 μm. The pump power was approximately 120 mW with a spectrum from 3.5 μm to 3.9 μm. First proof of principal experiments has been performed with 20 mW of averaged output power and a spectrum extending to 4.9 μm. The coupling efficiency of the SC radiation from the ZBLAN fiber into the AsSe fiber has been around 30%.

  6. Mechanisms of hot corrosion of a silicon carbide fiber-reinforced glass-ceramic

    SciTech Connect

    Kumar, A.; Fox, A.G.; Wang, Shaio-Wen

    1996-12-31

    Hot corrosion of a SiC (Nicalon) fiber-reinforced calcium aluminosilicate (CAS) has been investigated by x-ray diffraction and scanning electron microscopy. Samples of SiC/CAS and monolithic CAS were hot corroded by liquid sodium sulfate at 900{degrees}C for 50 hours in both air and argon. Corrosion damage in monolithic CAS was less severe as compared with the composite in both air and argon. The mechanisms of corrosion are discussed in terms of the kinetics of the dissociation of the sodium sulfate and its reaction with both the oxidized silicon carbide fibers and the CAS matrix.

  7. Epitaxy and fiber texture of Pb films on mica and glass.

    NASA Technical Reports Server (NTRS)

    Wyatt, P. W.; Yelon, A.

    1972-01-01

    We report the production of (111) epitaxial Pb films on mica and (111) textured Pb films on mica and glass. Film structure is studied by reflection electron diffraction and by etching and optical microscopy. Thin (about 1000 A) epitaxial films are found to be doubly positioned. Reorientation during growth of thicker films leads to single positioning in areas several tenths of a millimeter across.

  8. Dispersion engineering in soft glass photonic crystal fibers infiltrated with liquids

    NASA Astrophysics Data System (ADS)

    Stefaniuk, Tomasz; Le Van, Hieu; Pniewski, Jacek; Cao Long, Van; Ramaniuk, Aleksandr; Grajewski, Karol; Chu Van, Lanh; Karpierz, Mirosław; Trippenbach, Marek; Buczynski, Ryszard

    2015-12-01

    We present a numerical study of the dispersion characteristic modification in a nonlinear photonic crystal fibre (PCF) infiltrated with organic solvents. The PCF is made of PBG08 glass and was developed in the stack-and-draw process. The PBG08 glass has a high refractive index (n < 2.0), high nonlinear refractive index (n2 = 4.3×10-19 m2/W) and good rheological properties that allow for thermal processing of the glass without crystallization. In the numerical study 18 different solvents were used. The dispersion, mode area, and losses characteristics were calculated. The zero dispersion wavelength (ZDW) of the fibre can be shifted towards longer wavelengths by approx. 150 nm by using Nitrobenzene as infiltrating liquid and by a smaller value using other liquids. At the same time the mode area of the fundamental mode increases by approx. 5 to 15% depending on the wavelength considered. The confinement losses increase significantly for six analysed liquids by a few orders of magnitude up to 102 dB/m. Our approach allows to combine high nonlinearities of the soft glass with the possibility to tune zero dispersion wavelength to the desired value.

  9. Feasibility of silver doped TiO2/glass fiber photocatalyst under visible irradiation as an indoor air germicide.

    PubMed

    Pham, Thanh-Dong; Lee, Byeong-Kyu

    2014-03-01

    This study investigated the feasibility of using Ag-TiO2 photocatalyst supported on glass fiber (Ag-TiO2/GF) prepared by a sol-gel method as an indoor air germicide. An experimental model was designed to investigate the bacterial disinfection efficiency of Staphylococcus (Staph), the most popular bacterium in hospitals in Korea, by the Ag-TiO2/GF photocatalyst. The silver content in Ag/TiO2 was altered from 1 to 10% to investigate the optimal ratio of Ag doped on TiO2/glass fiber (TiO2/GF) for photocatalytic disinfection of Staph. This study confirmed that Ag in Ag-TiO2/GF could work as an electron sink or donor to increase photocatalytic activity and promote the charge separation of electron-hole pairs generated from TiO2 after photon absorption. Ag also acts as an intermediate agent for the transfer of photo-generated electrons from the valence band of TiO2 to an acceptor (O2 gas) to promote photo-oxidation processes. The photocatalytic disinfection activity of Ag-TiO2/GF under visible light increased with the increase in silver content up to 7.5% and then slightly decreased with further increasing silver content. The highest disinfection efficiency and disinfection capacity of Staph using 7.5% Ag-TiO2/GF were 75.23% and 20 (CFU∙s-1∙cm-2) respectively. The medium level of humidity of 60% ± 5% showed better photocatalytic disinfection than the lower (40% ± 5%) or higher (80% ± 5%) levels. PMID:24658408

  10. Effects of Heat Flux, Oxygen Concentration and Glass Fiber Volume Fraction on Pyrolysate Mass Flux from Composite Solids

    NASA Technical Reports Server (NTRS)

    Rich, D. B.; Lautenberger, C. W.; Yuan, Z.; Fernandez-Pello, A. C.

    2004-01-01

    Experimental work on the effects of heat flux, oxygen concentration and glass fiber volume fraction on pyrolysate mass flux from samples of polypropylene/glass fiber composite (PP/G) is underway. The research is conducted as part of a larger project to develop a test methodology for flammability of materials, particularly composites, in the microgravity and variable oxygen concentration environment of spacecraft and space structures. Samples of PP/G sized at 30 x 30 x 10 mm are flush mounted in a flow tunnel, which provides a flow of oxidizer over the surface of the samples at a fixed value of 1 m/s and oxygen concentrations varying between 18 and 30%. Each sample is exposed to a constant external radiant heat flux at a given value, which varies between tests from 10 to 24 kW/sq m. Continuous sample mass loss and surface temperature measurements are recorded for each test. Some tests are conducted with an igniter and some are not. In the former case, the research goal is to quantify the critical mass flux at ignition for the various environmental and material conditions described above. The later case generates a wider range of mass flux rates than those seen prior to ignition, providing an opportunity to examine the protective effects of blowing on oxidative pyrolysis and heating of the surface. Graphs of surface temperature and sample mass loss vs. time for samples of 30% PPG at oxygen concentrations of 18 and 21% are presented in the figures below. These figures give a clear indication of the lower pyrolysis rate and extended time to ignition that accompany a lower oxygen concentration. Analysis of the mass flux rate at the time of ignition gives good repeatability but requires further work to provide a clear indication of mass flux trends accompanying changes in environmental and material properties.

  11. Effects of Heat Flux, Oxygen Concentration and Glass Fiber Volume Fraction on Pyrolysate Mass Flux from Composite Solids

    NASA Technical Reports Server (NTRS)

    Rich, D. B.; Lautenberger, C. W.; Yuan, Z.; Fernandez-Pello, A. C.

    2004-01-01

    Experimental work on the effects of heat flux, oxygen concentration and glass fiber volume fraction on pyrolysate mass flux from samples of polypropylene/glass fiber composite (PP/G) is underway. The research is conducted as part of a larger project to develop a test methodology for flammability of materials, particularly composites, in the microgravity and variable oxygen concentration environment of spacecraft and space structures. Samples of PP/G sized at 30x30x10 mm are flush mounted in a flow tunnel, which provides a flow of oxidizer over the surface of the samples at a fixed value of 1 m/s and oxygen concentrations varying between 18 and 30%. Each sample is exposed to a constant external radiant heat flux at a given value, which varies between tests from 10 to 24 kW/m2. Continuous sample mass loss and surface temperature measurements are recorded for each test. Some tests are conducted with an igniter and some are not. In the former case, the research goal is to quantify the critical mass flux at ignition for the various environmental and material conditions described above. The later case generates a wider range of mass flux rates than those seen prior to ignition, providing an opportunity to examine the protective effects of blowing on oxidative pyrolysis and heating of the surface. Graphs of surface temperature and sample mass loss vs. time for samples of 30% PPG at oxygen concentrations of 18 and 21% are presented in the figures below. These figures give a clear indication of the lower pyrolysis rate and extended time to ignition that accompany a lower oxygen concentration. Analysis of the mass flux rate at the time of ignition gives good repeatability but requires further work to provide a clear indication of mass flux trends accompanying changes in environmental and material properties.

  12. Feasibility of Silver Doped TiO2/Glass Fiber Photocatalyst under Visible Irradiation as an Indoor Air Germicide

    PubMed Central

    Pham, Thanh-Dong; Lee, Byeong-Kyu

    2014-01-01

    This study investigated the feasibility of using Ag-TiO2 photocatalyst supported on glass fiber (Ag-TiO2/GF) prepared by a sol-gel method as an indoor air germicide. An experimental model was designed to investigate the bacterial disinfection efficiency of Staphylococcus (Staph), the most popular bacterium in hospitals in Korea, by the Ag-TiO2/GF photocatalyst. The silver content in Ag/TiO2 was altered from 1 to 10% to investigate the optimal ratio of Ag doped on TiO2/glass fiber (TiO2/GF) for photocatalytic disinfection of Staph. This study confirmed that Ag in Ag-TiO2/GF could work as an electron sink or donor to increase photocatalytic activity and promote the charge separation of electron-hole pairs generated from TiO2 after photon absorption. Ag also acts as an intermediate agent for the transfer of photo-generated electrons from the valence band of TiO2 to an acceptor (O2 gas) to promote photo-oxidation processes. The photocatalytic disinfection activity of Ag-TiO2/GF under visible light increased with the increase in silver content up to 7.5% and then slightly decreased with further increasing silver content. The highest disinfection efficiency and disinfection capacity of Staph using 7.5% Ag-TiO2/GF were 75.23% and 20 (CFU∙s−1∙cm−2) respectively. The medium level of humidity of 60% ± 5% showed better photocatalytic disinfection than the lower (40% ± 5%) or higher (80% ± 5%) levels. PMID:24658408

  13. [Influence of retainer design on fixation strength of resin-bonded glass fiber reinforced composite fixed cantilever dentures].

    PubMed

    Petrikas, O A; Voroshilin, Iu G; Petrikas, I V

    2013-01-01

    Fiber-reinforced composite (FRC) fixed partial dentures (FPD) have become an accepted part of the restorative dentist's armamentarium. The aim of this study was to evaluate in vitro the influence of retainer design on the strength of two-unit cantilever resin-bonded glass FRC-FPDs. Four retainer designs were tested: a dual wing, a dual wing + horizontal groove, a dual wing + occlusal rest and a step-box. Of each design on 7 human mandibular molars, FRC-FPDs of a premolar size were produced. The FRC framework was made of resin Revolution (Kerr) impregnated glass fibers (GlasSpan, GlasSpan) and veneered with hybrid resin composite (Charisma, Kulzer). Revolution (Kerr) was used as resin luting cement. FRC-FPDs were loaded to failure in a universal testing machine. T (Student's)-test was used to evaluate the data. The four designs were analyzed with finite element analysis (FEA) to reveal the stress distribution within the tooth/restoration complex. Significantly lower fracture strengths were observed with inlay-retained FPDs (step-box: 172±11 N) compared to wing-retained FPDs (p<0.05) (a dual wing + horizontal groove 222±9 N). The highest fracture strengths were observed with dual wing + occlusal rest FPDs: 250±10 N compared to inlay-retained FPDs (p<0.001) and wing-retained FPDs (p<0.001). FEA showed more favorable stress distributions within the tooth/restoration complex for dual wing retainers+ occlusal rest FPDs. There was stress concentration around connectors and retainers near connectors. A dual-wing retainer with occlusal rest is the optimal design for replacement of a single premolar by means of a two-unit cantilever FRC-FPDs. PMID:23715455

  14. The effect of joint surface contours and glass fiber reinforcement on the transverse strength of repaired acrylic resin: An in vitro study

    PubMed Central

    Anasane, Nayana; Ahirrao, Yogesh; Chitnis, Deepa; Meshram, Suresh

    2013-01-01

    Background: Denture fracture is an unresolved problem in complete denture prosthodontics. However, the repaired denture often experiences a refracture at the repaired site due to poor transverse strength. Hence, this study was conducted to evaluate the effect of joint surface contours and glass fiber reinforcement on the transverse strength of repaired acrylic resins. Materials and Methods: A total of 135 specimens of heat polymerized polymethyl methacrylate resin of dimensions 64 × 10 × 2.5 mm were fabricated. Fifteen intact specimens served as the control and 120 test specimens were divided into four groups (30 specimens each), depending upon the joint surface contour (butt, bevel, rabbet and round), with two subgroups based on type of the repair. Half of the specimens were repaired with plain repair resin and the other half with glass fibers reinforced repair resin. Transverse strength of the specimens was determined using three-point bending test. The results were analyzed using one-way ANOVA and Tukey post-hoc test (α= 0.05). Results: Transverse strength values for all repaired groups were significantly lower than those for the control group (P < 0.001) (88.77 MPa), with exception of round surface design repaired with glass fiber reinforced repair resin (89.92 MPa) which was significantly superior to the other joint surface contours (P < 0.001). Glass fiber reinforced resin significantly improved the repaired denture base resins as compared to the plain repair resin (P < 0.001). Conclusion: Specimens repaired with glass fiber reinforced resin and round surface design exhibited highest transverse strength; hence, it can be advocated for repair of denture base resins. PMID:23946739

  15. Survival of Composite Resin Restorations of severely Decayed Primary Anterior Teeth retained by Glass Fiber Posts or Reversed-orientated Metal Posts

    PubMed Central

    Ranjkesh, Bahram; Lovschall, Henrik; Erfanparast, Leila; Jafarabadi, Mohammad A; Oskouei, Sina Ghertasi; Isidor, Flemming

    2016-01-01

    ABSTRACT Aim: The aim of this study was to compare the survival of composite resin restorations retained by glass fiber posts or reversed-orientated (upside-down) metal posts in severely decayed primary anterior teeth after 6, 12, and 18 months. Materials and methods: A total of forty-four 3- to 5-year-old children with bilateral severely decayed primary maxillary canines were included. Patients were treated under general anesthesia. After pulpectomy, an intracanal post was seated in the primary maxillary canine on each side: either a glass fiber post or a metallic post in reversed orientation and teeth restored with light-cured composite. Survival rate of each technique was evaluated at predetermined follow-ups and data were analyzed with McNemar’s test (α = 0.05). Results: The difference in survival of restorations retained by two types of posts was not statistically significant in clinical and radiographical evaluations after 6, 12, and 18 months. The survival rate of reversed-orientated metal and glass fiber posts after 18 months was 81.1 and 67.6% respectively (p = 0.14). Conclusion: Reversed-orientated metal post did not show lower clinical survival compared with glass fiber posts in 18-month follow-up. Hence, reversed-orientated metal post can be considered as a potential method to obtain retention for composite restorations in severely decayed primary anterior teeth. How to cite this article: Vafaei A, Ranjkesh B, L0vschall H, Erfanparast L, Jafarabadi MA, Oskouei SG, Isidor F. Survival of Composite Resin Restorations of severely Decayed Primary Anterior Teeth retained by Glass Fiber Posts or Reversed-orientated Metal Posts. Int J Clin Pediatr Dent 2016;9(2):109-113. PMID:27365929

  16. Fabrication and characterization of multimaterial chalcogenide glass fiber tapers with high numerical apertures.

    PubMed

    Sun, Ya'nan; Dai, Shixun; Zhang, Peiqing; Wang, Xunsi; Xu, Yinsheng; Liu, Zijun; Chen, Feifei; Wu, Yuehao; Zhang, Yuji; Wang, Rongping; Tao, Guangming

    2015-09-01

    This paper reports on the fabrication and characterization of multimaterial chalcogenide fiber tapers that have high numerical apertures (NAs). We first fabricated multimaterial As(2)Se(3)-As(2)S(3) chalcogenide fiber preforms via a modified one-step coextrusion process. The preforms were drawn into multi- and single-mode fibers with high NAs (≈1.45), whose core/cladding diameters were 103/207 and 11/246 μm, respectively. The outer diameter of the fiber was tapered from a few hundred microns to approximately two microns through a self-developed automatic tapering process. Simulation results showed that the zero-dispersion wavelengths (ZDWs) of the tapers were shorter than 2 μm, indicating that the tapers can be conveniently pumped by commercial short wavelength infrared lasers. We also experimentally demonstrated the supercontinuum generation (SCG) in a 15-cm-long multimaterial As(2)Se(3)-As(2)S(3) chalcogenide taper with 1.9 μm core diameter and the ZDW was shifted to 3.3 μm. When pumping the taper with 100 fs short pulses at 3.4 µm, a 20 dB spectral of the generated supercontinuum spans from 1.5 μm to longer than 4.8 μm. PMID:26368447

  17. Improved patterning of ITO coated with gold masking layer on glass substrate using nanosecond fiber laser and etching

    NASA Astrophysics Data System (ADS)

    Tan, Nguyen Ngoc; Hung, Duong Thanh; Anh, Vo Tran; BongChul, Kang; HyunChul, Kim

    2015-05-01

    In this paper, an indium-tin oxide (ITO) thin-film patterning method for higher pattern quality and productivity compared to the short-pulsed laser direct writing method is presented. We sputtered a thin ITO layer on a glass substrate, and then, plated a thin gold layer onto the ITO layer. The combined structure of the three layers (glass-ITO-gold) was patterned using laser-induced plasma generated by an ytterbium pulsed fiber laser (λ = 1064 nm). The results showed that the process parameters of 50 mm/s in scanning speed, 14 ns pulse duration, and a repetition rate of 7.5 kHz represented optimum conditions for the fabrication of ITO channels. Under these conditions, a channel 23.4 μm wide and 20 nm deep was obtained. However, built-up spikes (∼15 nm in height) resulted in a decrease in channel quality, and consequently, short circuit occurred at some patterned positions. These built-up spikes were completely removed by dipping the ITO layer into an etchant (18 wt.% HCl). A gold masking layer on the ITO surface was found to increase the channel surface quality without any decrease in ITO thickness. Moreover, the effects of repetition rate, scanning speed, and etching characteristics on surface quality were investigated.

  18. Effect of irrigating solutions used for postspace treatment on the push-out bond strength of glass fiber posts

    PubMed Central

    Vangala, Amulya; Hegde, Vivek; Sathe, Sucheta; Dixit, Manisha; Jain, Paresh

    2016-01-01

    Aim: To evaluate the effect of different irrigating solutions on postspace treatments on the push-out bond strength of glass fiber posts. Materials and Methods: Thirty mandibular premolar roots were decoronated and endodontically treated. Postspaces were prepared and roots were divided into three groups: In group 1: 2.5% sodium hypochlorite irrigation (control), group 2: 17% ethylenediaminetetraacetic acid (EDTA) with hand activation, group 3: 17% EDTA irrigation with photon-induced photoacoustic streaming (PIPS) has been done to the postspaces. Scanning electron microscope (SEM) analysis has been made for two samples of each group. Fiber posts were then luted with resin cement. Each root was prepared for push-out test. Data have been statistically analyzed. Results: SEM results showed clean postwalls with both group 2 and group 3, whereas group 1 showed adhesion of resin cement to intraradicular dentine. When all groups were compared, the bond strength values are higher with group 2 followed by group 3. Conclusion: Within the limitations of the study, clean postwalls and the highest bond strength values were obtained from 17% EDTA with hand activation and 17% EDTA with PIPS. PMID:26957800

  19. Chromium doped nano-phase separated yttria-alumina-silica glass based optical fiber preform: fabrication and characterization

    NASA Astrophysics Data System (ADS)

    Dutta, Debjit; Dhar, Anirban; Das, Shyamal; Bysakh, Sandip; Kir'yanov, Alexandar; Paul, Mukul Chandra

    2015-06-01

    Transition metal (TM) doping in silica core optical fiber is one of the research area which has been studied for long time and Chromium (Cr) doping specially attracts a lot of research interest due to their broad emission band covering U, C and L band with many potential application such as saturable absorber or broadband amplifier etc. This paper present fabrication of Cr doped nano-phase separated silica fiber within yttria-alumina-silica core glass through conventional Modified Chemical Vapor Deposition (MCVD) process coupled with solution doping technique along with different material and optical characterization. For the first time scanning electron microscope (SEM) / energy dispersive X-ray (EDX) analysis of porous soot sample and final preform has been utilized to investigate incorporation mechanism of Crions with special emphasis on Cr-species evaporation at different stages of fabrication. We also report that optimized annealing condition of our fabricated preform exhibited enhanced fluorescence emission and a broad band within 550- 800 nm wavelength region under pumping at 532 nm wavelength due to nano-phase restructuration.

  20. Interface enhancement of glass fiber reinforced vinyl ester composites with flame-synthesized carbon nanotubes and its enhancing mechanism.

    PubMed

    Liao, Lingmin; Wang, Xiao; Fang, Pengfei; Liew, Kim Meow; Pan, Chunxu

    2011-02-01

    Interface enhancement with carbon nanotubes (CNTs) provides a promising approach for improving shock strength and toughness of glass fiber reinforced plastic (GFRP) composites. The effects of incorporating flame-synthesized CNTs (F-CNTs) into GFRP were studied, including on hand lay-up preparation, microstructural characterization, mechanical properties, fracture morphologies, and theoretical calculation. The experimental results showed that: (1) the impact strength of the GFRP modified by F-CNTs increased by more than 15% over that of the GFRP modified by CNTs from chemical vapor deposition; and (2) with the F-CNT enhancement, no interfacial debonding was observed at the interface between the fiber and resin matrix on the GFRP fracture surface, which indicated strong adhesive strength between them. The theoretical calculation revealed that the intrinsic characteristics of the F-CNTs, including lower crystallinity with a large number of defects and chemical functional groups on the surface, promoted their surface activity and dispersibility at the interface, which improved the interfacial bond strength of GFRP. PMID:21291279

  1. Sodium sulfate corrosion of silicon carbide fiber-reinforced lithium aluminosilicate glass-ceramic matrix composites. Master's thesis

    SciTech Connect

    Maldia, L.C.

    1993-12-01

    Sodium sulfate hot corrosion of a SiC fiber-reinforced lithium aluminosilicate (LAS) glass-ceramic matrix composite was studied using Scanning Electron Microscope (SEM) and X-ray Diffraction (XRD). Changes in the microstructural chemical composition of the specimens were investigated. The samples provided by Naval Air Warfare Center (NAWC), Warminster, PA were grouped as follows: (1) as-received, (2) Na2SO4 salt-coated and heat-treated in oxygen, (3) noncoated and heat-treated in oxygen, (4) Na2SO4. Salt-coated and heat-treated in argon, and (5) noncoated and heat-treated in argon. Heat treatment was performed by NAWC for 100 hours at 900 deg C. Experimental data obtained indicated that the presence of Na2SO4 in an oxidative environment resulted in rapid corrosion of the matrix and SiC fibers and in the latter rings of SiO2 replaced what had previously been SiC. There was very limited degradation of the fibers and matrix exposed at the surface in the noncoated sample heat-treated in oxygen and in the salt-coated sample heat-treated in argon. A significant reduction in the amount of mullite in the matrices of all heat-treated samples was observed. Mullite dissolved into either the glassy phase or into the Beta-spodumene matrix. Lastly, the presence of distinct magnesium silicate crystalline phases in the salt-coated and heat-treated in oxygen sample implies that the MgO at the surface reacted with the SiO2 in the matrix.

  2. Evaluation of the Load-bearing Capacity of Fractured Incisal Edge of Maxillary Permanent Central Incisors restored with a Glass Fiber-reinforced Nanocomposite: An in vitro Study

    PubMed Central

    Srilatha, KT; Nandlal, B; Dhull, Kanika Singh

    2015-01-01

    ABSTRACT Objectives: The aim of this study was to evaluate and compare the load-bearing capacity of fractured incisal edge of maxillary permanent central incisors restored with a nanocomposite and a glass fiber-reinforced nanocomposite. Materials and methods: Thirty-six extracted sound maxillary central incisors randomly divided in three groups were used for the present study. Group I (control) contained untreated teeth. Samples in experimental groups II and III were prepared by cutting the incisal (one-third) part of the crown horizontally and subjected to enamel preparations and restored with a nanocomposite and a glass fiber-reinforced nanocomposite respectively. All restored teeth were stored in distilled water at room temperature for 24 hours. Fracture resistance was evaluated as peak load at failure (Newton) for samples tested in a cantilever-bending test using Hounsfield universal testing machine. Failure modes were microscopically examined. Results: Highest mean peak failure load (Newton) among experimental groups was observed in glass fiber-reinforced nano composite group (863.50 ± 76.12 N) followed by nanocomposite group (633.67 ± 40.14 N). One-way analysis of variance (ANOVA) revealed that the restoration technique significantly affected the load-bearing capacity (p < 0.001). Scheffe’s post-hoc comparison test (subset for α = 0.05) revealed that there was significant difference in the mean peak failure load values of nanocomposite and glass fiber-reinforced nanocomposite groups when considered together (p < 0.001). Experimental groups showed similar types of failure modes with majority occurring ascohesive and mixed type. Fifty-eight percent of the teeth in glass fiber-reinforced nanocomposite group fractured below the cementoenamel junction. Conclusion: By using fiber-reinforced composite substructure under conventional composites in the repair of fractured incisors, the load-bearing capacity of the restored incisal edge could be substantially

  3. A study of reaction mechanisms in plasmas related to glass-fiber production

    NASA Astrophysics Data System (ADS)

    Saes, Ludovicus Henricus

    Use of the fertilizer industry waste product SiF4 for the manufacturing of optical fibers for telecommunication is discussed. The SiF4 can be obtained from H2SiF6, a by-product of the manufacturing process. A relatively simple distillation procedure can be used to remove impurities such as HF and the (salts of the) transition metals. After purification, SiF4 might be a proper raw material for production of solar grade silicon (photovoltaic cells) or pure quartz (optical fibers). However, application of SiF4 in a flame burner of chemical vapor deposition process is not feasible on thermodynamic grounds. In plasma processes, a sooty deposit is formed, and efficiency is a factor of 20 less compared with SiCl4. The reaction mechanisms in SiF4-O2 and SiCl4-O2 discharges were studied to explain this difference.

  4. Single gain peak from modulation instability in As2Se3 chalcogenide glass photonic crystal fiber

    NASA Astrophysics Data System (ADS)

    Wang, Helin; Yang, Aijun

    2016-09-01

    With the As2Se3 photonic crystal fiber (PCF), the effect of pump power and wavelength on modulation instability (MI) gain is studied in detail. Due to high Raman scattering effect and high nonlinearity of As2Se3 PCF, ultra-broadband MI gain is obtained when appropriate pump power and wavelength is chosen, and the optimal MI gain bandwidth reaches 2812 nm. More importantly, competing between Raman scattering and four-wave mixing results in a single gain peak observed in the anti-Stokes region of As2Se3 PCF when pump power is higher than about 3000 W, while there is no gain spectrum in the fiber Stokes region. The phenomenon is found for the first time, and the obtained single gain peak mainly results from Raman scattering effect.

  5. Investigation of upconversion luminescence in Yb3+/Tm3+/Ho3+ triply doped antimony-germanate glass and double-clad optical fiber

    NASA Astrophysics Data System (ADS)

    Zmojda, Jacek; Kochanowicz, Marcin; Miluski, Piotr; Righini, Giancarlo C.; Ferrari, Maurizio; Dorosz, Dominik

    2016-08-01

    The optical properties of novel antimony-germanate glass and optical fiber co-doped with Yb3+/Tm3+/Ho3+ ions were presented. White light luminescence in glass was observed as a result of energy transfer with upconversion between donor (Yb3+) and acceptors (Tm3+, Ho3+) ions under 976 nm excitation. The double-clad optical fiber with off-set core co-doped with Yb2O3/Tm2O3/Ho2O3 system was fabricated using a modified rod-in-tube technique. In glass co-doped with 0.5 mol%Yb2O3/0.1 mol%Tm2O3/0.2 mol%Ho2O3 the spectral distribution of three luminescence bands (478, 545 and 660 nm) corresponds to x = 0.35 and y = 0.32 CIE coordinates. In comparison to glass the optical fiber emission are located in the green region (CIE, x = 0.37, y = 0.49).

  6. Bonding Effectiveness of Two Adhesive Luting Cements to Glass Fiber Posts: Pull-Out Evaluation of Three Different Post Surface Conditioning Methods

    PubMed Central

    Calabrese, Marco

    2014-01-01

    The purpose of this study was to evaluate the bond strength at the post/resin-cement interface with 3 different surface treatments of glass fiber posts and with 2 different luting resin cements. Sixty glass fiber posts (RelyX Fiber Post) were randomly divided into 3 groups (n = 20) and were luted with a dual-polymerizing self-adhesive universal resin cement (RelyX Unicem) and with a dual-polymerizing resin cement (RelyX ARC). This was carried out in association with a dual-polymerizing adhesive (Scotchbond Multi-Purpose Plus) in simulated plexiglass root canals after receiving three different pretreatment procedures. A pull-out test was performed on each sample to measure bond strengths. Data were analyzed with two-way ANOVA. Two samples from each group were processed for SEM observations in order to investigate the morphologic aspect of the post/cement interface. Both resin cements demonstrated significant different bond strength values (P < 0.0001). The surface treatment result was also statistically significant (P = 0.0465). SEM examination showed a modification of the post surface after pretreatment with methyl methacrylate. The dual-polymerizing self-adhesive universal resin cement achieved higher MPa bond strength values. The use of methyl methacrylate as a surface treatment of glass fiber posts provided a significant increase in bond strengths between the posts and both luting materials. PMID:24987418

  7. Automobile accessories: Assessment and improvement

    SciTech Connect

    Jackson, M.

    1995-11-01

    With mandates and regulatory policies to meet both the California Air Resources Board (CARB) and the Partnership for a New Generation of Vehicles (PNGV), designing vehicles of the future will become a difficult task. As we look into the use of electric and hybrid vehicles, reduction of the required power demand by influential automobile components is necessary in order to obtain performance and range goals. Among those automobile components are accessories. Accessories have a profound impact on the range and mileage of future vehicles with limited amounts of energy or without power generating capabilities such as conventional vehicles. Careful assessment of major power consuming accessories helps us focus on those that need improvement and contributes to attainment of mileage and range goals for electric and hybrid vehicles.

  8. Experimental Study of the Flexural and Compression Performance of an Innovative Pultruded Glass-Fiber-Reinforced Polymer-Wood Composite Profile

    PubMed Central

    Qi, Yujun; Xiong, Wei; Liu, Weiqing; Fang, Hai; Lu, Weidong

    2015-01-01

    The plate of a pultruded fiber-reinforced polymer or fiber-reinforced plastic (FRP) profile produced via a pultrusion process is likely to undergo local buckling and cracking along the fiber direction under an external load. In this study, we constructed a pultruded glass-fiber-reinforced polymer-light wood composite (PGWC) profile to explore its mechanical performance. A rectangular cross-sectional PGWC profile was fabricated with a paulownia wood core, alkali-free glass fiber filaments, and unsaturated phthalate resin. Three-point bending and short column axial compression tests were conducted. Then, the stress calculation for the PGWC profile in the bending and axial compression tests was performed using the Timoshenko beam theory and the composite component analysis method to derive the flexural and axial compression rigidity of the profile during the elastic stress stage. The flexural capacity for this type of PGWC profile is 3.3-fold the sum of the flexural capacities of the wood core and the glass-fiber-reinforced polymer (GFRP) shell. The equivalent flexural rigidity is 1.5-fold the summed flexural rigidity of the wood core and GFRP shell. The maximum axial compressive bearing capacity for this type of PGWC profile can reach 1.79-fold the sum of those of the wood core and GFRP shell, and its elastic flexural rigidity is 1.2-fold the sum of their rigidities. These results indicate that in PGWC profiles, GFRP and wood materials have a positive combined effect. This study produced a pultruded composite material product with excellent mechanical performance for application in structures that require a large bearing capacity. PMID:26485431

  9. Experimental Study of the Flexural and Compression Performance of an Innovative Pultruded Glass-Fiber-Reinforced Polymer-Wood Composite Profile.

    PubMed

    Qi, Yujun; Xiong, Wei; Liu, Weiqing; Fang, Hai; Lu, Weidong

    2015-01-01

    The plate of a pultruded fiber-reinforced polymer or fiber-reinforced plastic (FRP) profile produced via a pultrusion process is likely to undergo local buckling and cracking along the fiber direction under an external load. In this study, we constructed a pultruded glass-fiber-reinforced polymer-light wood composite (PGWC) profile to explore its mechanical performance. A rectangular cross-sectional PGWC profile was fabricated with a paulownia wood core, alkali-free glass fiber filaments, and unsaturated phthalate resin. Three-point bending and short column axial compression tests were conducted. Then, the stress calculation for the PGWC profile in the bending and axial compression tests was performed using the Timoshenko beam theory and the composite component analysis method to derive the flexural and axial compression rigidity of the profile during the elastic stress stage. The flexural capacity for this type of PGWC profile is 3.3-fold the sum of the flexural capacities of the wood core and the glass-fiber-reinforced polymer (GFRP) shell. The equivalent flexural rigidity is 1.5-fold the summed flexural rigidity of the wood core and GFRP shell. The maximum axial compressive bearing capacity for this type of PGWC profile can reach 1.79-fold the sum of those of the wood core and GFRP shell, and its elastic flexural rigidity is 1.2-fold the sum of their rigidities. These results indicate that in PGWC profiles, GFRP and wood materials have a positive combined effect. This study produced a pultruded composite material product with excellent mechanical performance for application in structures that require a large bearing capacity. PMID:26485431

  10. The Effect of Temperature and Nanoclay on the Low Velocity and Ballistic Behavior of Woven Glass-Fiber Reinforced Composites

    NASA Astrophysics Data System (ADS)

    Patrin, Lauren

    The objective of this research was to study the effect of nanoclay and temperature on the behavior of woven glass-fabric reinforced epoxy composite under low velocity and ballistic impacts. The materials used in manufacturing the composite were S2 (6181) glass-fibers, epoxy resin (EPON 828), hardener (Epikure 3230), nanoclay and Heloxy 61 modifier. The nanoclay addition was 0%, 1%, 3% and 5% by weight, with respect to the resin. All specimens were manufactured at the City College facilities using vacuum infusion. Tensile tests were conducted to characterize the material and obtain the Young's modulus, ultimate stress, failure strain, Poisson's ratio, shear modulus and shear strength and their variation with nanoclay percentage and temperature. The tests were conducted at room temperature (21°C/70°F), -54°C (-65°F), -20°C (-4°F), 49°C (120°F) and 71°C (160°F). Next composite specimens with 0%, 1%, 3% and 5% nanoclay by weight, with respect to the resin, were subjected to low velocity impact at the previously specified temperatures to determine dynamic force, displacement and energy correlations. The extent of damage was studied using the ultrasound technique. Then ballistic tests were conducted on the nanoclay infused specimens at room temperature to obtain the ballistic limit (V50) and the damage behavior of the composite. The dynamic finite element analysis (FEA) software LS-DYNA was used to model and simulate the results of low velocity impact tests. Good agreement was obtained between experimental and numerical (FEA) results. Analytical analyses were undertaken to compare the results from the tensile experiments. The finite element analysis (FEA) allowed for further analytical comparison of the results. The FEA platform used was LS-DYNA due to its proficient dynamic and damage capabilities in composite materials. The FEA was used to model and simulate the low velocity impacts and compare the results to experiments.

  11. Fire tests on insulation for aluminum tank cars: an evaluation of glass-fiber, ceramic-fiber, and mineral-fiber materials in torch-fire and pool-fire environments. Final report

    SciTech Connect

    Larson, W.G.

    1987-08-01

    Tests were conducted at the Transportation Test Center to determine the vulnerability to fire of aluminum tank cars designed to transport hazardous materials under pressure when the aluminum was protected by three types of insulation. Glass, mineral, and ceramic fiber blankets, each covering a speciment of aluminum plate commonly used in tank car construction, were subjected to standard torch-fire and pool-fire tests while instrumentation recorded the rise in temperature of the aluminum plate. The data derived from the tests will be used by the FRA to build the information base required for an examination of the vulnerability of aluminum tank cars to both mechanical and thermal accidents. The report presents details of the 20 tests performed by the Research and Test Department of the Association of American Railroads. It compares the thermal-protective qualities of the three individual types of insulation covering the aluminum and includes a comparative test series on bare aluminum plate.

  12. Effect of embedded printed circuit board (PCB) sensors on the mechanical behavior of glass fiber-reinforced polymer (GFRP) structures

    NASA Astrophysics Data System (ADS)

    Javdanitehran, M.; Hoffmann, R.; Groh, J.; Vossiek, M.; Ziegmann, G.

    2016-06-01

    The embedding of dielectric chipless sensors for cure monitoring into fiber-reinforced thermosets allows for monitoring and controlling the curing process and consequently higher quality in production. The embedded sensors remain after the processing in the structure. This affects the integrity of the composite structure locally. In order to investigate these effects on the mechanical behavior of the glass fiber-reinforced polymer (GFRP), sensors made on special low loss substrates are integrated into laminates with different lay-ups and thicknesses using vacuum assisted resin transfer molding (VARTM) method. In a parametric study the size of the sensor is varied to observe its influence on the strength and the stiffness of the laminates according to its lay-up and thickness. The size and orientation of the resin rich areas near sensors as well as the distortion in load bearing area as the consequences of the introduction of the sensors are investigated in conjunction with the strength of the structure. An empirical model is proposed by the authors which involves the previously mentioned factors and is used as a rapid tool for the prediction of the changes in bending and tensile strength of simple structures with embedded sensors. The methodology for model’s calibration as well as the validation of the model against the experimental data of different laminates with distinct lay-ups and thicknesses are presented in this work. Mechanical tests under tensile and bending loading indicate that the reduction of the structure’s strength due to sensor integration can be attributed to the size and the orientation of rich resin zones and depends over and above on the size of distorted load bearing area. Depending on the sensor’s elastic modulus the stiffness of the structure may vary through the introduction of a sensor.

  13. Modeling the Fatigue Behavior of Glass Fiber Reinforced Thermoplastic and Thermosetting Matrices

    NASA Astrophysics Data System (ADS)

    D'Amore, Alberto; Grassia, Luigi; Verde, Pasquale

    2012-07-01

    The flexural fatigue behavior of continuous and short glass reinforced composites was investigated under four-point bending loading. The effect of mean stress and stress amplitude was identified. It was found that the fatigue life decreased rapidly with the decreasing stress ratio (i.e. the ratio between the minimum and the maximum stress). Further, the specimen lifetime for any loading mode increased with : (a) decreasing load range and decreasing stress ratio and (b) decreasing mean load and increasing stress ratio. From the above observations a brand new two-parameter model based on strength degradation was developed accounting for both the mean load and the load range, in order to express analytically the strength variation during fatigue cycle evolution.

  14. Glass fiber laser at 1. 36. mu. m from SiO sub 2 :Nd

    SciTech Connect

    Hakimi, F.; Po, H.; Tumminelli, R.; McCollum, B.C.; Zenteno, L.; Cho, N.M.; Snitzer, E. )

    1989-10-01

    By adding 14 mol % P{sub 2}O{sub 5} to the core of a SiO{sub 2}:Nd fiber, laser emission was obtained at 1.36 {mu}m. From the fluorescent spectra and laser thresholds for the {sup 4}{ital F}{sub 3/2} to {sup 4}{ital I}{sub 11/2} and {sup 4}{ital F}{sub 3/2} to {sup 4}{ital I}{sub 3/2} transitions, the net gain at 1.36 {mu}m is 0.024 dB/mW, and the ratio of excited-state absorption (the {sup 4}{ital F}{sub 3/2} to {sup 4}{ital G}{sub 1/2} transition) to stimulated emission is estimated to be 0.78.

  15. Effects of Porosity on Ultrasonic Characteristic Parameters and Mechanical Properties of Glass Fiber Reinforced Composites

    NASA Astrophysics Data System (ADS)

    Ma, Wen; Liu, Fushun

    Voids are inevitable in the fabrication of fiber reinforced composites and have a detrimental impact on mechanical properties of composites. Different void contents were acquired by applying different vacuum bag pressures. Ultrasonic inspection and ablation density method were adopted to measure the ultrasonic characteristic parameters and average porosity, the characterization of voids' distribution, shape and size were carried out through metallographic analysis. Effects of void content on the tensile, flexural and interlaminar shear properties and the ultrasonic characteristic parameters were discussed. The results showed that, as vacuum bag pressure went from -50kPa to -98kPa, the voids content decreased from 4.36 to 0.34, the ultrasonic attenuation coefficient decreased, but the mechanical strengths all increased.

  16. 21 CFR 878.4950 - Manual operating table and accessories and manual operating chair and accessories.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Manual operating table and accessories and manual... Surgical Devices § 878.4950 Manual operating table and accessories and manual operating chair and accessories. (a) Identification. A manual operating table and accessories and a manual operating chair...

  17. The Use of Glass-fibers Ribbon and Composite for Prosthetic Restoration of Missing Primary Teeth-Laboratory and Clinical Research

    PubMed Central

    Zilberman, Uri; Lasilla, Lippo

    2014-01-01

    Very few modalities can be used for restoring missing primary anterior teeth, although the impact of missing anterior teeth during early childhood can be harmful. In the permanent dentition the use of glass-fibers ribbon and composite materials are frequently used for restoring missing teeth with no or minimal preparation. The purpose of this study was to examine the possibility to use the glass-fibers ribbon (ever-Stick from GC Corporation, Japan) together with esthetic composite materials (G-aenial A1 from GC Corporation, Japan) for restoring anterior primary teeth and to determine the best methodology and bonding system to be used. The effect of etching time was analyzed using 20-80 sec on primary buccal enamel with SEM and the results showed that at least 60 second is necessary in order to remove the prismless layer and to affect the prismatic layer similar (as observed by SEM) to the 20 sec etching time on permanent enamel. Three bonding systems (SE Bond by Kurary, Japan, Scotchbond Universal by 3M/ESPE, Germany and G-aenial bond by GC Company, Japan) were compared for bonding the glass-fibers ribbon to the primary enamel and microtensile strength analyses were performed. Mean tensile strength ranged from 10.9 to 13 MPa with no statistically significant differences between all three systems. Based on the laboratory results it can be concluded that the glass-fibers ribbon together with the composite material can be used clinically to restore missing primary teeth for esthetic and functional reasons. Two clinical cases are presented that show favorable results. PMID:25553140

  18. Teaching Techniques for Accessory Percussion

    ERIC Educational Resources Information Center

    Micallef, Ken

    2007-01-01

    Everyone is familiar with the main percussion instruments of the contemporary orchestra: bass drum, snare drum, suspended cymbal, vibraphone, and timpani. But as source material broadens, so do the demands placed on the percussion section. Accessory, or auxiliary percussion, can make the difference between a typical rendition of a well-known piece…

  19. Effects of heat treating silane and different etching techniques on glass fiber post push-out bond strength.

    PubMed

    Samimi, P; Mortazavi, V; Salamat, F

    2014-01-01

    The aims of this study were to compare two pretreatment methods of a fiber post and to evaluate the effect of heat treatment to applied silane on the push-out bond strength for different levels of root. In this in vitro study, 40 glass fiber posts were divided into five groups (n=8) according to the kind of surface treatment applied. They were then inserted into extracted and endodontically treated human canines using a self-etch resin cement (Panavia F2.0, Kuraray, Japan). Group HF+S = hydrofluoric acid (HF) etching and silane (S) application; group HF+S+WP = HF etching and heat-treated silane application and warmed posts (WP); group H2O2+S = hydrogen peroxide etching and silane application; group H2O2+S+WP = hydrogen peroxide and heat-treated-silane application and warmed post; and group C, the control group, received no pretreatment. After completion of thermal cycling (1000 cycles, 5-55°C), all specimens were cut horizontally to obtain three sections. Each section was subjected to a push-out test, and the test results were analyzed using two-way analysis of variance, post-hoc Tukey honestly significant difference test, and a paired sample t-test (α=0.05). It was found that bond strength was not statistically influenced by the kind of etching material used (p=0.224), but was significantly affected by heat treatment of applied silane (p<0.001). The interaction between these two factors was not statistically significant (p=0.142). Group HF+S+WP showed the highest bond strength (12.56±1.73 MPa) (p<0.05). Scanning electron microscopy revealed the effect of the different treatments on the surface characteristics of posts. In the four pretreated groups, the bond strength decreased significantly from the coronal to the apical root canal sections (p≤0.05). The results of this study show that the use of heat-treated silane significantly enhances the push-out bond strength of the fiber posts to root. HF acid etching with heat-treated silane application led to the

  20. 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. ...

  1. 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 ...

  2. 14 CFR 25.1167 - Accessory gearboxes.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 14 Aeronautics and Space 1 2013-01-01 2013-01-01 false Accessory gearboxes. 25.1167 Section 25... Accessory gearboxes. For airplanes equipped with an accessory gearbox that is not certificated as part of an engine— (a) The engine with gearbox and connecting transmissions and shafts attached must be subjected...

  3. 14 CFR 25.1167 - Accessory gearboxes.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 14 Aeronautics and Space 1 2014-01-01 2014-01-01 false Accessory gearboxes. 25.1167 Section 25... Accessory gearboxes. For airplanes equipped with an accessory gearbox that is not certificated as part of an engine— (a) The engine with gearbox and connecting transmissions and shafts attached must be subjected...

  4. 14 CFR 25.1167 - Accessory gearboxes.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 14 Aeronautics and Space 1 2011-01-01 2011-01-01 false Accessory gearboxes. 25.1167 Section 25... Accessory gearboxes. For airplanes equipped with an accessory gearbox that is not certificated as part of an engine— (a) The engine with gearbox and connecting transmissions and shafts attached must be subjected...

  5. 14 CFR 25.1167 - Accessory gearboxes.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 14 Aeronautics and Space 1 2012-01-01 2012-01-01 false Accessory gearboxes. 25.1167 Section 25... Accessory gearboxes. For airplanes equipped with an accessory gearbox that is not certificated as part of an engine— (a) The engine with gearbox and connecting transmissions and shafts attached must be subjected...

  6. 14 CFR 25.1167 - Accessory gearboxes.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Accessory gearboxes. 25.1167 Section 25... Accessory gearboxes. For airplanes equipped with an accessory gearbox that is not certificated as part of an engine— (a) The engine with gearbox and connecting transmissions and shafts attached must be subjected...

  7. Comparative evaluation of fracture resistance of glass fiber reinforced, carbon, and quartz post in endodontically treated teeth: An in-vitro study

    PubMed Central

    Sharma, Shweta; Attokaran, George; Singh, Kunwar S.; Jerry, Jeethu J.; Ahmed, Naima; Mitra, Nirban

    2016-01-01

    Aim and Objectives: Use of posts improves the physical properties of endodontically-treated teeth. Different post types are developed such as metal, custom-made, carbon, and quartz. The present study was conducted to evaluate the fracture resistance of glass fiber-reinforced, carbon, and quartz post in endodontically-treated teeth. Materials and Methods: Forty extracted human maxillary incisor teeth were decoronated and endodontically treated and equally divided into 4 groups; control, glass fiber-reinforced, carbon, and quartz posts. No post was used in the control group. Post space was prepared and cemented with different posts and subjected to universal testing machine to check fracture resistance. The data were statistically analyzed using t-test and analysis of variance to compare the mean difference between groups (SPSS version 20, IBM). Results: Quartz type of endodontic post showed good fracture resistance compared to carbon and resin-reinforced post. Least resistance was observed in the control group without post. Conclusion: Quartz, carbon, and glass fiber-reinforced posts show good resistance to fracture, and hence can be used in endodontically-treated teeth to enhance their strength. PMID:27583227

  8. Tuning the mechanical properties of glass fiber-reinforced bismaleimide-triazine resin composites by constructing a flexible bridge at the interface

    NASA Astrophysics Data System (ADS)

    Zeng, Xiaoliang; Yu, Shuhui; Lai, Maobai; Sun, Rong; Wong, Ching-Ping

    2013-12-01

    We demonstrate a new method that can simultaneously improve the strength and toughness of the glass fiber-reinforced bismaleimide-triazine (BT) resin composites by using polyethylene glycol (PEG) to construct a flexible bridge at the interface. The mechanical properties, including the elongation, ultimate tensile stress, Young's modulus, toughness and dynamical mechanical properties were studied as a function of the length of PEG molecular chain. It was found that the PEG molecule acts as a bridge to link BT resin and glass fiber through covalent and non-covalent bondings, respectively, resulting in improved interfacial bonding. The incorporation of PEG produces an increase in elongation, ultimate tensile stress and toughness. The Young's modulus and Tg were slightly reduced when the length of the PEG molecular chain was high. The elongation of the PEG-modified glass fiber-reinforced composites containing 5 wt% PEG-8000 increased by 67.1%, the ultimate tensile stress by 17.9% and the toughness by 78.2% compared to the unmodified one. This approach provides an efficient way to develop substrate material with improved strength and toughness for integrated circuit packaging applications.

  9. Analysis of upconversion luminescence in germanate glass and optical fiber codoped with Yb3+/Tb3+.

    PubMed

    Kochanowicz, M; Zmojda, J; Miluski, P; Sitarz, M; Pisarska, J; Pisarski, W A; Dorosz, D

    2016-03-20

    In this paper, upconversion (UC) luminescence processes in a GeO2-Ga2O3-BaO glass system codoped with 0.7Yb2O3/(0.07-0.7)Tb2O3 (mol.%) and double-clad optical fiber codoped with 0.7Yb2O3/0.7Tb2O3 (mol.%) were investigated. The highest emission intensity (energy transfer efficiency equals 12.92%) was obtained for 0.7Yb2O3/0.7Tb2O3 codoped glass. Comparative analysis showed significant differences in the shape of luminescence of fabricated germanate glass and optical fiber. Due to dominant transition from D45 sublevel the main green UC peak (Tb3+:  D45→F57) of fabricated double-clad optical fiber is shifted by 4 nm toward longer wavelengths. PMID:27140575

  10. Effect of fabrication processes on mechanical properties of glass fiber reinforced polymer composites for 49 meter (160 foot) recreational yachts

    NASA Astrophysics Data System (ADS)

    Kim, Dave (dea-wook); Hennigan, Daniel John; Beavers, Kevin Daniel

    2010-03-01

    Polymer composite materialsoffer high strength and stiffness to weight ratio, corrosion resistance, and total life cost reductions that appeal to the marine industry. The advantages of composite construction have led to their incorporation in U.S. yacht hull structures over 46 meters (150 feet) in length. In order to construct even larger hull structures, higher quality composites with a lower cost production techniques need to be developed. In this study, the effect of composite hull fabrication processes on mechanical properties of glass fiber reinforced plastic(GFRP) composites is presented. Fabrication techniques used in this study are hand lay-up (HL), vacuum infusion (VI), and hybrid (HL+VI) processes. Mechanical property testing includes: tensile, compressive, and ignition loss sample analysis. Results demonstrate that the vacuum pressure implemented during composite fabrication has an effect on mechanical properties. The VI processed GFRP yields improved mechanical properties in tension/compression strengths and tensile modulus. The hybrid GFRP composites, however, failed in a sequential manor, due to dissimilar failure modes in the HL and VI processed sides. Fractography analysis was conducted to validate the mechanical property testing results

  11. Irradiation Effect of 14 MeV Neutron on Interlaminar Shear Strength of Glass Fiber Reinforced Plastics

    SciTech Connect

    Nishimura, A.; Hishinuma, Y.; Seo, K.; Tanaka, T.; Muroga, T.; Nishijima, S.; Katagiri, K.; Takeuchi, T.; Shindo, Y.; Ochiai, K.; Nishitani, T.; Okuno, K.

    2006-03-31

    Design activity of International Thermonuclear Experimental Reactor clarifies intense neutron streaming from ports for neutral beam injectors. Energy spectrum of the streaming is very wide and 14 MeV neutron and gamma ray are the typical radiations. Large amount of glass fiber reinforced plastics will be used in a superconducting magnet system as an electric insulation material and a support structure, for such organic material is easy to manufacture, and light and cheap. In this report, effects of 14 MeV neutron and gamma ray irradiation on interlaminar shear strength and fracture mode are investigated using G-10CR small specimen of which configuration was proposed as a standard for evaluation of the interlaminar shear strength. A short beam test under three point bending was conducted at room temperature and 77 K. Neutron fluence of 3.91 x 1019 n/m2 was irradiated and the specimens did not show clear degradation of the strength. On the other hand, gamma ray irradiation of 1 MGy made the specimen weaker and 10 MGy caused delamination. Most of the specimens showed both of interlaminar cracking and bending fracture, but some specimens were fractured with irregular shear occurred on the planes connecting loading point and supporting points.

  12. Plasma vitrification and re-use of non-combustible fiber reinforced plastic, gill net and waste glass.

    PubMed

    Chu, J P; Chen, Y T; Mahalingam, T; Tzeng, C C; Cheng, T W

    2006-12-01

    Fiber reinforced plastic (FRP) composite material has widespread use in general tank, special chemical tank and body of yacht, etc. The purpose of this study is directed towards the volume reduction of non-combustible FRP by thermal plasma and recycling of vitrified slag with specific procedures. In this study, we have employed three main wastes such as, FRP, gill net and waste glass. The thermal molten process was applied to treat vitrified slag at high temperatures whereas in the post-heat treatment vitrified slags were mixed with specific additive and ground into powder form and then heat treated at high temperatures. With a two-stage heat treatment, the treated sample was generated into four crystalline phases, cristobalite, albite, anorthite and wollastonite. Fine and relatively high dense structures with desirable properties were obtained for samples treated by the two-stage heating treatment. Good physical and mechanical properties were achieved after heat treatment, and this study reveals that our results could be comparable with the commercial products. PMID:16839685

  13. Damage micromechanisms and notch sensitivity of glass-fiber non-woven felts: An experimental and numerical study

    NASA Astrophysics Data System (ADS)

    Ridruejo, Alvaro; González, Carlos; LLorca, Javier

    2010-10-01

    The deformation and damage micromechanisms of a glass-fiber non-woven felt were analyzed with a combination of experiments and simulations. Tensile tests were carried out on unnotched and notched rectangular panels to ascertain the physical phenomena which control the development of damage. It was found that fracture began by interbundle bond fracture followed by frictional sliding between bundles, leading to the localization of damage in a wide band. The mechanical behavior of the non-woven felt until final fracture was modeled by the finite element simulation of a 2D random network in which the geometric characteristics of the network and the constituent properties were obtained from experiments on the actual non-woven felt. The simulation results were in very good agreement with the experiments in terms of the macroscopic response and of the microscopic mechanisms. They contributed to explain different features of the experimental data, including the effect of specimen dimensions on the strength and the notch-insensitive behavior of the material.

  14. Evaluating quality of adhesive joints in glass-fiber plastic piping by using active thermal NDT

    NASA Astrophysics Data System (ADS)

    Grosso, M.; Marinho, C. A.; Nesteruk, D. A.; Rebello, J. M.; Soares, S. D.; Vavilov, V. P.

    2013-05-01

    GRP-type composites (Glass-fibre Reinforced Plastics) have been continuously employed in the oil industry in recent years, often on platforms, especially in pipes for water or oil under moderate temperatures. In this case, the pipes are usually connected through adhesive joints and, consequently, the detection of defects in these joints, as areas without adhesive or adhesive failure (disbonding), gains great importance. One-sided inspection on the joint surface (front side) is a challenging task because the material thickness easily exceeds 10 mm that is far beyond the limits of the capacity of thermography applied to GRP inspection, as confirmed by the experience. Detection limits have been evaluated both theoretically and experimentally as a function of outer wall thickness and defect lateral size. The 3D modeling was accomplished by using the ThermoCalc-6L software. The experimental unit consisted of a FLIR SC640 and NEC TH- 9100 IR imagers and some home-made heaters with the power from 1,5 to 30 kW. The results obtained by applying pulsed heating have demonstrated that the inspection efficiency is strongly dependent on the outer wall thickness with a value of about 8 mm being a detection limit.

  15. Mechanical resistance evaluation of a novel anatomical short glass fiber reinforced post in artificial endodontically treated premolar under rotational/lateral fracture fatigue testing.

    PubMed

    Wang, Hsuan-Wen; Chang, Yen-Hsiang; Lin, Chun-Li

    2016-01-01

    This study develops a novel anatomical short glass fiber reinforced (anatomical SGFR) post and evaluates the mechanical performance in artificial endodontically treated premolars. An anatomical SGFR fiber post with an oval shape and slot/notch designs was manufactured using an injection-molding machine. The three-point bending test and crown/core restorations using the anatomical SGFR and commercial cylindrical fiber posts under fatigue test were executed to understand the mechanical resistances. The results showed that static and dynamic rotational resistance were found significantly higher in the anatomical SGFR fiber post than in the commercial post. The endurance limitations at 1.2×10(6) cycles were 66.81 and 64.77 N for the anatomical SGFR and commercial fiber posts, respectively. The anatomical SGFR fiber post presented acceptable value of flexural strength and modulus, better fit adaption in the root canal resist torque more efficiency but was not a key issue in the lateral fracture resistance in an endodontically treated premolar. PMID:27041013

  16. Mechanical properties of resin glass fiber-reinforced abutment in comparison to titanium abutment

    PubMed Central

    Andreasi Bassi, Mirko; Bedini, Rossella; Pecci, Raffella; Ioppolo, Pietro; Lauritano, Dorina; Carinci, Francesco

    2015-01-01

    Purpose: So far, definitive implant abutments have been performed with high elastic modulus materials, which prevented any type of shock absorption of the chewing loads and as a consequence, the protection of the bone-fixture interface. This is particularly the case when the esthetic restorative material chosen is ceramic rather than composite resin. The adoption of an anisotropic abutment, characterized by an elastic deformability, could allow decreasing the impulse of chewing forces transmitted to the crestal bone. Materials and Methods: According to research protocol, the mechanical resistance to cyclical load was evaluated in a tooth-colored fiber-reinforced abutment (TCFRA) prototype and compared to that of a titanium abutment (TA), thus eight TCFRAs and eight TAs were adhesively cemented on as many titanium implants. The swinging that the two types of abutments showed during the application of sinusoidal load was also analyzed. Results: In the TA group, both fracture and deformation occurred in 12.5% of samples while debonding 62.5%. In the TCFRA group, only debonding was present in 37.5% of samples. In comparison to the TAs, the TCFRAs exhibited a greater swinging during the application of sinusoidal load. In the TA group, the extrusion prevailed, whereas in the TCFRA group, the intrusion was more frequent. Conclusion: The greater elasticity of TCFRA to the flexural load allows absorbing part of the transversal load applied on the fixture during the chewing function, thus reducing the stress on the bone-implant interface. PMID:26229266

  17. Fracture mechanics applied to the analysis of the degradation of anti-corrosion glass/resin pipes as a function of the fiber/matrix interface quality

    SciTech Connect

    Krawczak, P.; Pabiot, J.

    1995-10-01

    The aim of this paper is to propose a characterization method of the damage of glass/epoxy pipes, based on mode 1 fracture mechanics, making it possible to separate the cracks initiation and cracks propagation mechanisms that exist in practice. In a first part, it is shown that this technique is highly sensitive (in factors 4 to 5) to the fiber/matrix interface quality, the latter being either modified by the use of different sizings or degraded by hydrothermal aging. In a second part, the application of this method to pipes under pressure shows that mode I fracture mechanics tests performed on unidirectionally fiber reinforced flat test pieces monoaxially loaded allow the explanation of the short term as well as long term behavior and damage of complex composite structures under biaxial loading, and this on the basis of the participation of the fiber/matrix interface to the observed phenomena.

  18. Constitutive modelling of creep in a long fiber random glass mat thermoplastic composite

    NASA Astrophysics Data System (ADS)

    Dasappa, Prasad

    The primary objective of this proposed research is to characterize and model the creep behaviour of Glass Mat Thermoplastic (GMT) composites under thermo-mechanical loads. In addition, tensile testing has been performed to study the variability in mechanical properties. The thermo-physical properties of the polypropylene matrix including crystallinity level, transitions and the variation of the stiffness with temperature have also been determined. In this work, the creep of a long fibre GMT composite has been investigated for a relatively wide range of stresses from 5 to 80 MPa and temperatures from 25 to 90°C. The higher limit for stress is approximately 90% of the nominal tensile strength of the material. A Design of Experiments (ANOVA) statistical method was applied to determine the effects of stress and temperature in the random mat material which is known for wild experimental scatter. Two sets of creep tests were conducted. First, preliminary short-term creep tests consisting of 30 minutes creep followed by recovery were carried out over a wide range of stresses and temperatures. These tests were carried out to determine the linear viscoelastic region of the material. From these tests, the material was found to be linear viscoelastic up-to 20 MPa at room temperature and considerable non-linearities were observed with both stress and temperature. Using Time-Temperature superposition (TTS) a long term master curve for creep compliance for up-to 185 years at room temperature has been obtained. Further, viscoplastic strains were developed in these tests indicating the need for a non-linear viscoelastic viscoplastic constitutive model. The second set of creep tests was performed to develop a general non-linear viscoelastic viscoplastic constitutive model. Long term creep-recovery tests consisting of 1 day creep followed by recovery has been conducted over the stress range between 20 and 70 MPa at four temperatures: 25°C, 40°C, 60°C and 80°C. Findley's model

  19. Effect of weight fraction of carbon black and number of plies of E-glass fiber to reflection loss of E-glass/ripoxy composite for radar absorbing structure (RAS)

    NASA Astrophysics Data System (ADS)

    Widyastuti, Ramadhan, Rizal; Ardhyananta, Hosta; Zainuri, Mochamad

    2013-09-01

    Nowadays, studies on investigating radar absorbing structure (RAS) using fiber reinforced polymeric (FRP) composite materials are becoming popular research field because the electromagnetic properties of FRP composites can be tailored effectively by just adding some electromagnetic powders, such as carbon black, ferrite, carbonyl iron, and etc., to the matrix of composites. The RAS works not only as a load bearing structure to hold the antenna system, but also has the important function of absorbing the in-band electromagnetic wave coming from the electromagnetic energy of tracking systems. In this study, E-glass fiber reinforced ripoxy resin composite was fabricated by blending the conductive carbon black (Ketjenblack EC300J) with the binder matrix of the composite material and maximizing the coefficient of absorption more than 90% (more than -10 dB) within the X-band frequency (8 - 12 GHz). It was measured by electrical conductivity (LCR meter) and vector network analyzer (VNA). Finally, the composite RAS with 0.02 weight fraction of carbon black and 4 plies of E-glass fiber showed thickness of 2.1 mm, electrical conductivity of 8.33 × 10-6 S/m, and maximum reflection loss of -27.123 dB, which can absorb more than 90% of incident EM wave throughout the entire X-band frequency range, has been developed.

  20. Factors affecting on bond strength of glass fiber post cemented with different resin cements to root canal

    NASA Astrophysics Data System (ADS)

    Clavijo, V. R. G.; Bandéca, M. C.; Calixto, L. R.; Nadalin, M. R.; Saade, E. G.; Oliveira-Junior, O. B.; Andrade, M. F.

    2009-09-01

    Luting materials provides the retention of endodontic post. However, the failures of endodontic posts predominantly occurred are the losses of retention. Thus, the alternating use to remove the smear layer, open the dentine tubules, and/or etch the inter-tubular dentine can be provided by EDTA. This study was performed to evaluate effect of EDTA on bond strength of glass fiber post cemented with different resin cements to root canal. Fifty bovine incisors were selected and the crowns were removed to obtain a remaining 14-mm-height root. The roots were randomly distributed into five groups: GI: RelyX™ ARC/LED; GII: RelyX™ U100/LED; GIII EDTA/RelyX™ U100/LED; GIV: Multilink™; and GV: EDTA/Multlink™. After endodontic treatment, the post space was prepared with the drills designated for the quartz-coated-carbon-fiber post Aestheti-Post®. Before application of resin cements, root canals were irrigated with 17% EDTA (GIII and GV) during 1 min, rinsed with distilled water and dried using paper points. The light-cured materials were light-activated with UltraLume LED 5 (Ultradent, South Jordan, Utah) with power density of 1315 mW/cm2. Specimens were perpendicularly sectioned into approximately 1 mm thick sections and the stubs were performed on Universal Testing Machine. The analysis of variance (ANOVA) and Tukey’s post-hoc tests showed significant statistical different between RelyX™ ARC (GI) and RelyX™ U100 independent of the pre-treatment (GII to GIII) ( P < 0.05). The Multlink™ showed between RelyX™ ARC and RelyX™ U100 (GI to GIII; GII to GV) ( P < 0.05). The ANOVA showed significant statistical similar ( P > 0.05) to all resin cements between the Cervical to Apical regions (GI to GV). The use of 17% EDTA showed no difference significant between the resin cements evaluated (GII to GIII; GIV to GV). Within the limitations of the current study, it can be concluded that the use of EDTA did not provide efficiency on bond strength. The RelyX™ ARC