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Sample records for eu-doped b2o3-zno-pbo glass

  1. Sintering process of Eu doped luminescent glass prepared from porous glass

    International Nuclear Information System (INIS)

    Akai, T; Murakami, M; Yamashita, M; Okajima, T; Umesaki, N

    2011-01-01

    Eu doped high silica glass prepared by sintering porous glass exhibits blue luminescence with high quantum efficiency. In this work, we studied effects of sintering temperature on valance state of europium ion. To investigate a change of valance state of Eu, X-ray absorption near edge structure (XANES) spectroscopy measurements were carried out. Intensity of blue emission at around 430nm drastically increases when the sintering temperature is above 1000 deg. C. From XANES spectra, it is found that almost all the Eu exist as Eu 3+ in a samples sintered below 900 deg. C, while more than 70% of Eu exist as Eu 2+ in the sample sintered at 1050 deg. C and 1100 deg. C. The drastic change of oxidation state of europium ion between 900 and 1050 deg. C is discussed in relation to the structural change probed by infrared (IR) spectroscopy.

  2. Composition dependence of the optical and structural properties of Eu-doped oxyfluoride glasses

    International Nuclear Information System (INIS)

    Zhu, Chaofeng; Wu, Dongqun; Zhang, Yanfei; Zhang, Meimei; Yue, Yuanzheng

    2015-01-01

    Highlights: • Eu doped oxyfluoride glasses for LED applications are studied. • Conversion of Eu 3+ to Eu 2+ is realized in the glasses prepared in air atmosphere. • CaF 2 crystals formed during melt cooling enhance the conversion of Eu 3+ to Eu 2+ . • Content of CaF 2 crystals can be controlled by adjusting base glass compositions. - Abstract: Europium doped oxyfluoride glasses were prepared by the melt quenching method for the light emitting diodes applications. The optical and structural properties of these glasses were studied by means of photoluminescence spectra, Commission Internationale de L’Eclairage chromaticity coordinates, X-ray diffraction, and Fourier transform infrared spectra. We find that the spontaneous reduction of Eu 3+ to Eu 2+ is realized by Eu 3+ ions occupying the sites of Ca 2+ in the glasses prepared in air atmosphere. The Eu 3+ to Eu 2+ conversion efficiency, optical performances and structure of the glasses strongly depend on the base glass compositions. For certain base glass compositions, CaF 2 crystals can form during the melt cooling process, and thereby enhance the conversion from Eu 3+ to Eu 2+ . The formation of CaF 2 crystals can be suppressed by adding CaO, Al 2 O 3 and B 2 O 3 , but enhanced by adding Na 2 O and K 2 O in glass compositions. Finally, we propose a mechanism to explain how the glass structure affects the reduction of Eu ions as well as optical properties of the glasses

  3. Dy:Eu doped CaBAl glasses for white light applications

    Science.gov (United States)

    Lodi, T. A.; Sandrini, M.; Medina, A. N.; Barboza, M. J.; Pedrochi, F.; Steimacher, A.

    2018-02-01

    The combination of Eu3+ and Dy3+ in co-doped glassy materials provides interesting applicability for white light emission devices. In this work, Dy:Eu doped Calcium Boroaluminate (CaBAl) glasses were prepared by conventional melting quenching, with 3 wt% of Dy2O3 and Eu2O3 content varying from 0 to 3 wt%, and results of absorption spectra, photoluminescence and photoluminescence lifetime are discussed in terms of Eu2O3 content. The photoluminescence of the samples was studied under excitation of 365 and 405 nm light source. The 365 nm excitation shows favor to the Dy3+ ion emission. The results of photoluminescence lifetime at 575 nm (Dy3+) shows a decrease due to Eu2O3 addition, which suggests an energy transfer from Dy3+ (donor) to the Eu3+ (acceptor). On the other hand, under excitation of 405 nm, the photoluminescence lifetime at 575 nm (Dy3+) shows no significant changes due to Eu2O3 amount, which indicates that the energy transfer from Dy3+ to Eu3+ (under λexc = 405 nm) is negligible. However, the results of photoluminescence under 405 nm excitation present a white yellowish emission in the CIE diagram, which shifts to red with Eu2O3 addition. The combination of a Blue LED (BL) emission with the emission of the samples was also studied in the CIE diagram, in order to improve light emission and to obtain ideal White Light (WL). The results show that by modifying the emission intensity of BL, it is possible to achieve a route for smart lighting, close to the circadian light cycle.

  4. Optical and spectroscopic properties of Eu-doped tellurite glasses and glass ceramics

    International Nuclear Information System (INIS)

    Stambouli, W.; Elhouichet, H.; Gelloz, B.; Férid, M.

    2013-01-01

    Tellurite glasses doped with trivalent europium were prepared by the conventional melt quenching technique, in the chemical composition of (85−x) TeO 2 +5La 2 O 3 +10TiO 2 +xEu 2 O 3 by varying the concentration of the rare-earth ion in the order 0.5, 1 and 1.5 mol%. Using Judd–Ofelt analysis, we calculated intensity parameters (Ω 2 and Ω 4 ), spontaneous emission probabilities, the radiative lifetime, luminescence branching factors, the quantum yield of luminescence, and the stimulated emission cross-sections for 5 D 0 → 7 F 2 transition. The change in optical properties with the variation of Eu 3+ ion concentration have been discussed and compared with other glasses. The luminescence intensity ratio, quantum efficiency and emission cross-section values support that the TeEu1.5 tellurite glass is a suitable candidate for red laser source applications. Optical properties for Eu 3+ doped tellurite glass, heated for different temperature, were investigated. Crystalline phases for α-TeO 2 , γ-TeO 2 and TiTe 3 O 8 system were determined by the XRD method. The effect of heat treatment on luminescence properties in the tellurite glass was discussed. By using Eu 3+ as a probe, the local structure of rare-earth ion in tellurite glass, vitro-ceramic and ceramic glass has been investigated. The evaluated J–O intensity parameters have been used to calculate different radiative and laser characteristic parameters of the 5 D 0 excited level. The large magnitudes of stimulated emission cross-section (σ e ), branching ratio (β) and Gain bandwidth (σ e ×Δλ eff ) obtained for 5 D 0 → 7 F 2 (613 nm) transition for ceramic glass indicate that the present glass ceramic is promising host material for Eu 3+ doped fiber amplifiers. The measured lifetime of 5 D 0 excited state increases with increase of the heat treatment which further indicate that some Eu 3+ ions were successfully embedded in the crystal phase and prove the low phonon energy environment of Eu 3+ ions

  5. Composition dependence of the optical and structural properties of Eu-doped oxyfluoride glasses

    DEFF Research Database (Denmark)

    Zhu, C.F.; Wu, D.Q.; Zhang, Y.F.

    2015-01-01

    Europium doped oxyfluoride glasses were prepared by the melt quenching method for the light emitting diodes applications. The optical and structural properties of these glasses were studied by means of photoluminescence spectra, Commission Internationale de L'Eclairage chromaticity coordinates, X...... compositions. Finally, we propose a mechanism to explain how the glass structure affects the reduction of Eu ions as well as optical properties of the glasses.......Europium doped oxyfluoride glasses were prepared by the melt quenching method for the light emitting diodes applications. The optical and structural properties of these glasses were studied by means of photoluminescence spectra, Commission Internationale de L'Eclairage chromaticity coordinates, X...... on the base glass compositions. For certain base glass compositions, CaF2 crystals can form during the melt cooling process, and thereby enhance the conversion from Eu3+ to Eu2+. The formation of CaF2 crystals can be suppressed by adding CaO, Al2O3 and B2O3, but enhanced by adding Na2O and K2O in glass...

  6. Eu-doped ZnO-HfO2 hybrid nanocrystal-embedded low-loss glass-ceramic waveguides

    Science.gov (United States)

    Ghosh, Subhabrata; N, Shivakiran Bhaktha B.

    2016-03-01

    We report on the sol-gel fabrication, using a dip-coating technique, of low-loss Eu-doped 70SiO2 -(30-x) HfO2-xZnO (x = 2, 5, 7 and 10 mol%) ternary glass-ceramic planar waveguides. Transmission electron microscopy and grazing incident x-ray diffraction experiments confirm the controlled growth of hybrid nanocrystals with an average size of 3 nm-25 nm, composed of ZnO encapsulated by a thin layer of nanocrystalline HfO2, with an increase of ZnO concentration from x = 2 mol% to 10 mol% in the SiO2-HfO2 composite matrix. The effect of crystallization on the local environment of Eu ions, doped in the ZnO-HfO2 hybrid nanocrystal-embedded glass-ceramic matrix, is studied using photoluminescence spectra, wherein an intense mixed-valence state (divalent as well as trivalent) emission of Eu ions is observed. The existence of Eu2+ and Eu3+ in the SiO2-HfO2-ZnO ternary matrix is confirmed by x-ray photoelectron spectroscopy. Importantly, the Eu{}2+,3+-doped ternary waveguides exhibit low propagation losses (0.3 ± 0.2 dB cm-1 at 632.8 nm) and optical transparency in the visible region of the electromagnetic spectrum, which makes ZnO-HfO2 nanocrystal-embedded SiO2-HfO2-ZnO waveguides a viable candidate for the development of on-chip, active, integrated optical devices.

  7. Femtosecond laser-induced reduction in Eu-doped sodium borate glasses

    Energy Technology Data Exchange (ETDEWEB)

    Lim, Ki-Soo [Department of Physics and Basic Science Research Institute, Chungbuk National University, Cheongju 361-763 (Korea, Republic of)]. E-mail: kslim@chungbuk.ac.kr; Lee, Sunkyun [Department of Physics and Basic Science Research Institute, Chungbuk National University, Cheongju 361-763 (Korea, Republic of); Trinh, Minh-Tuan [Department of Physics and Basic Science Research Institute, Chungbuk National University, Cheongju 361-763 (Korea, Republic of); Kim, Suk-Ho [Department of Physics and Basic Science Research Institute, Chungbuk National University, Cheongju 361-763 (Korea, Republic of); Lee, Myeongkyu [Departent of Materials Science and Engineering, Yonsei University, 134 Shinchon-dong, Seoul 120-749 (Korea, Republic of); Hamilton, Douglas S. [Department of Physics, University of Connecticut, Storrs, CT 06269 (United States); Gibson, George N. [Department of Physics, University of Connecticut, Storrs, CT 06269 (United States)

    2007-01-15

    In this work, we report permanent reduction of Eu{sup 3+} to Eu{sup 2+} in sodium borate glasses by irradiation of near-infrared femtosecond laser. Glass composition of sodium borate was 85B{sub 2}O{sub 3}-15Na{sub 2}O. The glasses were doped with 0.05, 0.1, and 0.5 mol% Eu{sub 2}O{sub 3}. Absorption and fluorescence dynamics were studied to investigate valence state change of europium ions and the energy transfer between Eu{sup 2+} and Eu{sup 3+} ions. As the femtosecond laser intensity or exposure time increases, the emission band at 400 nm becomes stronger. However, the photoreduction efficiency decreases as the dopant concentration increases. We discuss the photoreduction mechanism under multiphoton absorption.

  8. On the induction of homogeneous bulk crystallization in Eu-doped calcium aluminosilicate glass by applying simultaneous high pressure and temperature

    Energy Technology Data Exchange (ETDEWEB)

    Muniz, R. F., E-mail: robsonfmuniz@yahoo.com.br [Institut Lumière Matière, UMR 5306 CNRS-Université Lyon 1, Université de Lyon, 69622 Villeurbanne (France); Departamento de Física, Universidade Estadual de Maringá, 87020900, Maringá, PR (Brazil); Ligny, D. de [Department of Materials Science, Glass and Ceramics, University of Erlangen Nürnberg, Martensstr. 5, 91058 Erlangen (Germany); Le Floch, S.; Martinet, C.; Guyot, Y. [Institut Lumière Matière, UMR 5306 CNRS-Université Lyon 1, Université de Lyon, 69622 Villeurbanne (France); Rohling, J. H.; Medina, A. N.; Sandrini, M.; Baesso, M. L. [Departamento de Física, Universidade Estadual de Maringá, 87020900, Maringá, PR (Brazil); Andrade, L. H. C.; Lima, S. M. [Grupo de Espectroscopia Óptica e Fototérmica, Universidade Estadual de Mato Grosso do Sul, C.P. 351, Dourados, MS (Brazil)

    2016-06-28

    From initial calcium aluminosilicate glass, transparent glass-ceramics have been successfully synthesized under simultaneous high pressure and temperature (SHPT). Possible homogeneous volumetric crystallization of this glassy system, which was not achieved previously by means of conventional heat treatment, has been put in evidence with a SHPT procedure. Structural, mechanical, and optical properties of glass and glass-ceramic obtained were investigated. Raman spectroscopy and X-ray diffraction allowed to identify two main crystalline phases: merwinite [Ca{sub 3}Mg(SiO{sub 4}){sub 2}] and diopside [CaMgSi{sub 2}O{sub 6}]. A Raman scanning profile showed that the formation of merwinite is quite homogeneous over the bulk sample. However, the sample surface also contains significant diopside crystals. Instrumented Berkovich nanoindentation was applied to determine the effect of SHPT on hardness from glass to glass-ceramic. For Eu-doped samples, the broadband emission due to 4f{sup 6}5d{sup 1} → 4f{sup 7} transition of Eu{sup 2+} was studied in both host systems. Additionally, the {sup 5}D{sub 0} → {sup 7}F{sub J} transition of Eu{sup 3+} was used as an environment probe in the pristine glass and the glass-ceramic.

  9. Structural and Optical Properties of Eu Doped ZnO Nanorods prepared by Pulsed Laser Deposition

    KAUST Repository

    Alarawi, Abeer

    2014-01-01

    Nano structured wide band gap semiconductors have attracted attention of many researchers due to their potential electronic and optoelectronic applications. In this thesis, we report successful synthesis of well aligned Eu doped ZnO nano

  10. First-principles study on electronic structures and magnetic properties of Eu-doped phosphorene

    Science.gov (United States)

    Luan, Zhaohui; Zhao, Lei; Chang, Hao; Sun, Dan; Tan, Changlong; Huang, Yuewu

    2017-11-01

    The structural, electronic and magnetic properties of Eu-doped phosphorene with different doping concentrations were investigated by first-principles calculations for the first time. The calculations show that Eu-doped phosphorene systems are stable and have the large magnetic moments of more than 6 μB by 2.7, 6.25 and 12.5 at.% doping concentrations. The major contribution to the magnetic moment stems from the 4f states of Eu-doped atom. Meanwhile, Eu-doped atom introduces the impurity bands which can be changed by different doping concentrations. In order to determine the magnetic interaction, the different configurations for two Eu atoms doping in 3 × 3 × 1 phosphorene supercell were studied, which reveals that all of the configurations tend to form ferromagnetic. These results can provide references for inducing large magnetism of two-dimensional phosphorene, which are valuable for their applications in spintronic devices and novel semiconductor materials.

  11. 380 keV proton irradiation effects on photoluminescence of Eu-doped GaN

    International Nuclear Information System (INIS)

    Okada, Hiroshi; Nakanishi, Yasuo; Wakahara, Akihiro; Yoshida, Akira; Ohshima, Takeshi

    2008-01-01

    The effect of 380 keV proton irradiation on the photoluminescence (PL) properties has been investigated for undoped and Eu-doped GaN. As the proton irradiation exceeds 1x10 13 cm -2 , a drastic decrease of PL intensity of the near band-edge emission of undoped GaN was observed. On the other hand, for Eu-doped GaN, the PL emission corresponding to the 5 D 0 → 7 F 2 transition in Eu 3+ kept the initial PL intensity after the proton irradiation up to 1x10 14 cm -2 . Present results, together with our previous report on electron irradiation results, suggest that Eu-doped GaN is a strong candidate for light emitting devices in high irradiation environment

  12. Red luminescence from hydrothermally synthesized Eu-doped ZnO ...

    Indian Academy of Sciences (India)

    Administrator

    turally characterized by X-ray diffraction, transmission electron microscopy ... II–VI compound semiconductor with large exciton binding .... ions occupy a site with inversion symmetry and 617 nm ... TEM image of Eu-doped ZnO nanoparticles with (a) 1⋅2 at. .... Jacquier B, Lebrasseur E, Guy S, Belarouci A and Menchini F.

  13. Photoluminescent properties of spider silk coated with Eu-doped nanoceria

    Energy Technology Data Exchange (ETDEWEB)

    Dmitrović, Svetlana, E-mail: svetlana8@vin.bg.ac.rs [University of Belgrade, Vinča Institute of Nuclear Sciences (Serbia); Nikolić, Marko G.; Jelenković, Branislav [University of Belgrade, Institute of Physics (Serbia); Prekajski, Marija [University of Belgrade, Vinča Institute of Nuclear Sciences (Serbia); Rabasović, Mihailo [University of Belgrade, Institute of Physics (Serbia); Zarubica, Aleksandra [University of Niš, Department of Chemistry, Faculty of Science and Mathematics (Serbia); Branković, Goran [University of Belgrade, Institute for Multidisciplinary Research, Department of Material Science (Serbia); Matović, Branko [University of Belgrade, Vinča Institute of Nuclear Sciences (Serbia)

    2017-02-15

    Spider dragline silk was coated with pure as well as Eu-doped ceria nanopowders at the room temperature. The treatment was done by immersion of the spider silk mesh into aqueous solutions of cerium nitrate (Ce(NO{sub 3}){sub 3}) and ammonium hydroxide (NH{sub 4}OH). Depending on the relationship between Ce{sup 3+} ion and ammonium hydroxide concentration, coated fibers exhibited a different thickness. Obtained materials were studied by means of FESEM. It was found that ceria nanoparticles of average size of 3 nm were coated along spider thread. X-ray diffraction (XRD) and selected-area electron diffraction (SAED) confirmed crystal nature of nanoparticle coating of spider silk. By using Williamson-Hall plots, crystallite size and strain were estimated. EDS measurement confirmed the presence of Eu in spider-Eu-doped ceria composite, and according to FTIR analysis, the interaction between CeO2 and spider silk was proposed. The morphology of obtained composite was observed by TEM. The photoluminescence emission spectra of spider silk coated with Eu-doped ceria were measured with two different excitations of 385 and 466 nm. The two-photon excited auto-fluorescence of spider silk coated with Eu-doped ceria was detected using a nonlinear laser scanning microscope. Obtained composite has a potential as a fluorescent labeling material in diverse applications.

  14. Photoluminescent properties of spider silk coated with Eu-doped nanoceria

    International Nuclear Information System (INIS)

    Dmitrović, Svetlana; Nikolić, Marko G.; Jelenković, Branislav; Prekajski, Marija; Rabasović, Mihailo; Zarubica, Aleksandra; Branković, Goran; Matović, Branko

    2017-01-01

    Spider dragline silk was coated with pure as well as Eu-doped ceria nanopowders at the room temperature. The treatment was done by immersion of the spider silk mesh into aqueous solutions of cerium nitrate (Ce(NO_3)_3) and ammonium hydroxide (NH_4OH). Depending on the relationship between Ce"3"+ ion and ammonium hydroxide concentration, coated fibers exhibited a different thickness. Obtained materials were studied by means of FESEM. It was found that ceria nanoparticles of average size of 3 nm were coated along spider thread. X-ray diffraction (XRD) and selected-area electron diffraction (SAED) confirmed crystal nature of nanoparticle coating of spider silk. By using Williamson-Hall plots, crystallite size and strain were estimated. EDS measurement confirmed the presence of Eu in spider-Eu-doped ceria composite, and according to FTIR analysis, the interaction between CeO2 and spider silk was proposed. The morphology of obtained composite was observed by TEM. The photoluminescence emission spectra of spider silk coated with Eu-doped ceria were measured with two different excitations of 385 and 466 nm. The two-photon excited auto-fluorescence of spider silk coated with Eu-doped ceria was detected using a nonlinear laser scanning microscope. Obtained composite has a potential as a fluorescent labeling material in diverse applications.

  15. Enhanced luminescence in Eu-doped ZnO nanocrystalline films

    Energy Technology Data Exchange (ETDEWEB)

    Suzuki, Keigo, E-mail: ksuzuki@murata.com; Murayama, Koji; Tanaka, Nobuhiko [Murata Manufacturing Co., Ltd., 10-1, Higashikotari 1-chome, Nagaokakyo, Kyoto 617-8555 (Japan)

    2015-07-20

    We found an enhancement of Eu{sup 3+} emissions in Eu-doped ZnO nanocrystalline films fabricated by microemulsion method. The Eu{sup 3+} emission intensities were increased by reducing annealing temperatures from 633 K to 533 K. One possible explanation for this phenomenon is that the size reduction enhances the energy transfer from ZnO nanoparticles to Eu{sup 3+} ions. Also, the shift of the charge-transfer band into the low-energy side of the absorption edge is found to be crucial, which seems to expedite the energy transfer from O atoms to Eu{sup 3+} ions. These findings will be useful for the material design of Eu-doped ZnO phosphors.

  16. Nitrate-assisted photocatalytic efficiency of defective Eu-doped Pr(OH)3 nanostructures.

    Science.gov (United States)

    Aškrabić, S; Araújo, V D; Passacantando, M; Bernardi, M I B; Tomić, N; Dojčinović, B; Manojlović, D; Čalija, B; Miletić, M; Dohčević-Mitrović, Z D

    2017-12-06

    Pr(OH) 3 one-dimensional nanostructures are a less studied member of lanthanide hydroxide nanostructures, which recently demonstrated an excellent adsorption capacity for organic pollutant removal from wastewater. In this study, Pr 1-x Eu x (OH) 3 (x = 0, 0.01, 0.03, and 0.05) defective nanostructures were synthesized by a facile and scalable microwave-assisted hydrothermal method using KOH as an alkaline metal precursor. The phase and surface composition, morphology, vibrational, electronic and optical properties of the as-prepared samples were characterized by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), inductively coupled plasma optical emission spectrometry (ICP-OES), transmission electron microscopy (TEM), field emission scanning electron microscopy (FE-SEM), Raman, infrared (IR), photoluminescence (PL), and diffuse reflectance spectroscopy (DRS). It was deduced that the incorporation of Eu 3+ ions promoted the formation of oxygen vacancies in the already defective Pr(OH) 3 , subsequently changing the Pr(OH) 3 nanorod morphology. The presence of KNO 3 phase was registered in the Eu-doped samples. The oxygen-deficient Eu-doped Pr(OH) 3 nanostructures displayed an improved photocatalytic activity in the removal of reactive orange (RO16) dye under UV-vis light irradiation. An enhanced photocatalytic activity of the Eu-doped Pr(OH) 3 nanostructures was caused by the synergetic effect of oxygen vacancies and Eu 3+ (NO 3 - ) ions present on the Pr(OH) 3 surface, the charge separation efficiency and the formation of the reactive radicals. In addition, the 3% Eu-doped sample exhibited very good adsorptive properties due to different morphology and higher electrostatic attraction with the anionic dye. Pr 1-x Eu x (OH) 3 nanostructures with the possibility of tuning their adsorption/photocatalytic properties present a great potential for wastewater treatment.

  17. Dosimeter properties of Ce and Eu doped LiCaAlF6

    International Nuclear Information System (INIS)

    Yanagida, Takayuki; Fujimoto, Yutaka; Watanabe, Kenichi; Fukuda, Kentaro

    2014-01-01

    Optical, scintillation properties, optical stimulated luminescence, and thermally stimulated luminescence of Ce 1, 3, and 5% doped and Eu 1, 1.5, and 2% doped LiCaAlF 6 crystals fabricated by Tokuyama Corp. were investigated. In transmittance, absorption was proportional to dopant concentrations and typical optical quantum yield of Ce and Eu-doped LiCaAlF 6 were 40 and 100%, respectively. Scintillation wavelength and decay time profiles were investigated under X-ray irradiation. Ce 3+ and Eu 2+ 5d-4f luminescence appeared around 300 nm and 370 nm with typical decay time of 40 ns and 1.5 μs, respectively. Optically stimulated luminescence of Ce-doped ones appeared under 405 nm stimulation with detectable intensity while those of Eu doped ones were quite weak. Thermally stimulated luminescence of Ce- and Eu-doped LiCaAlF 6 were enough strong and they exhibited good response function from 1 to 1000 mGy exposure. - Highlights: • Optical, scintillation, OSL, and TSL properties of Ce or Eu differently doped LiCaAlF6 were studied. • PL quantum yield of Ce and Eu doped LiCaAlF6 showed 40% and 100%, respectively. • OSL was observed in Ce-doped LiCaAlF6. • TSL was observed in both material systems and exhibited a good dose response from 1 to 1000 mGy

  18. Structural and Optical Properties of Eu Doped ZnO Nanorods prepared by Pulsed Laser Deposition

    KAUST Repository

    Alarawi, Abeer

    2014-06-23

    Nano structured wide band gap semiconductors have attracted attention of many researchers due to their potential electronic and optoelectronic applications. In this thesis, we report successful synthesis of well aligned Eu doped ZnO nano-rods prepared, for the first time to our knowledge, by pulsed laser deposition (PLD) without any catalyst. X-ray diffraction (XRD) patterns shows that these Eu doped ZnO nanorods are grown along the c-axis of ZnO wurtzite structure. We have studied the effect of the PLD growth conditions on forming vertically aligned Eu doped ZnO nanorods. The structural properties of the material are investigated using a -scanning electron microscope (SEM). The PLD parameters must be carefully controlled in order to obtain c-axis oriented ZnO nanorods on sapphire substrates, without the use of any catalyst. The experiments conducted in order to identify the optimal growth conditions confirmed that, by adjusting the target-substrate distance, substrate temperature, laser energy and deposition duration, the nanorod size could be successfully controlled. Most importantly, the results indicated that the photoluminescence (PL) properties reflect the quality of the ZnO nanorods. These parameters can change the material’s structure from one-dimensional to two-dimensional however the laser energy and frequency affect the size and the height of the nanorods; the xygen pressure changes the density of the nanorods.

  19. UV and electron radiation-induced luminescence of Cu- and Eu-doped lithium tetraborates

    Energy Technology Data Exchange (ETDEWEB)

    Ignatovych, M.; Holovey, V.; Watterich, A.; Vidoczy, T.; Baranyai, P.; Kelemen, A.; Ogenko, V.; Chuiko, O

    2003-06-01

    Cu- and Eu-doped Li{sub 2}B{sub 4}O{sub 7} has been characterized using steady-state and time-resolved photoluminescence, radioluminescence and optical absorption techniques. The effect of dopant content (7.0x10{sup -4}-5.0x10{sup -2} wt% for Cu and 1.6x10{sup -3}-8.0x10{sup -3} wt% for Eu) and of host modification (single crystal, polycrystalline and glassy) has been investigated.

  20. Magnetic properties of Eu doped BiGdO{sub 3}

    Energy Technology Data Exchange (ETDEWEB)

    Nithya, R., E-mail: nithya@igcar.gov.in; Yadagiri, K. [Materials Science Group, Indira Gandhi Centre for Atomic Research, Kalpakkam, 603 102, TN (India); Shukla, Neeraj [UGC-DAE-CSR Kalpakkam Node, Kokilamedu-603 104, TN (India)

    2016-05-23

    Bulk Bismuth Gadolinium Oxide, BiGdO{sub 3} and Eu doped BiGdO{sub 3} compounds were synthesized by the conventional solid state reaction in air. Phase formation of these compounds was tracked using powder X-ray characterization technique since single phase formation was found to be sensitive to thermal treatment parameters such as cooling and heating rates. Analysis of X-ray diffraction patterns revealed cubic structure with Pm-3m symmetry. An antiferromagnetic transition around 3.8 K was observed in the pristine compound whereas doped samples showed paramagnetic nature in the whole measured temperature range.

  1. Fabrication of Eu doped CdO [Al/Eu-nCdO/p-Si/Al] photodiodes by perfume atomizer based spray technique for opto-electronic applications

    Science.gov (United States)

    Ravikumar, M.; Ganesh, V.; Shkir, Mohd; Chandramohan, R.; Arun Kumar, K. Deva; Valanarasu, S.; Kathalingam, A.; AlFaify, S.

    2018-05-01

    In this study, thin films of cadmium oxide (CdO) with different concentrations (0, 1, 3, and 5 wt%) of Eu doping were deposited onto Si and glass substrates by a novel and facile spray technique using simple perfume atomizer for the first time. Prepared films were characterized for structural, morphological, optical properties and the photo diode studies, using X-ray diffraction, scanning electron microscope, UV-Vis spectrophotometer, Isbnd V characteristics, and fundamental parameters are reported. All the prepared Eu:CdO films exhibit cubic structure. The preferential orientation is along (200) plane. Scanning electron microscopy study indicates the growth of smooth and pin-hole free films with clusters of homogeneous grains. The values of band gap energy are found to be varying from 2.42 to 2.33 eV for various Eu doping concentration from 0 to 5 wt%. EDAX studies revealed the presence of Eu, Cd and O elements without any other impurities. FTIR spectra showed a peak at 575 cm-1 confirming the stretching mode of Cdsbnd O. The resistivity (ρ), high carrier concentration (n) and carrier mobility (μ) for 3 wt% CdO thin film are found to be 0.452 × 10-3(Ω.cm), 17.82 × 1020 cm-3 and 7.757 cm2/V, respectively. Current-voltage measurements on the fabricated nanostructured Al/Eu-nCdO/p-Si/Al heterojunction device showed a non-linear electric characteristics indicating diode like behaviour.

  2. Optical properties, luminescence quenching mechanism and radiation hardness of Eu-doped GaN red powder phosphor

    International Nuclear Information System (INIS)

    Jadwisienczak, W.; Wisniewski, K.; Spencer, M.; Thomas, T.; Ingram, D.

    2010-01-01

    We report on the luminescence quenching mechanism of Eu-doped GaN powder phosphor produced with a low-cost, high yield rapid-ammonothermal method. We have studied as-synthesized and acid rinsed Eu-doped GaN powders with the Eu concentration of ∼0.5 at.%. The Eu-doped GaN photoluminescence (PL) was investigated with 325 nm excitation wavelength at hydrostatic pressures up to 7.7 GPa in temperature range between 12 K and 300 K. The room temperature integrated Eu 3+ ion PL intensity from acid rinsed material is a few times stronger than from the as-synthesized material. The temperature dependent PL studies revealed that the thermal quenching of the dominant Eu 3+ ion transition ( 5 D 0 → 7 F 2 ) at 622 nm is stronger in the chemically modified phosphor indicating more efficient coupling between the Eu 3+ ion and passivated GaN powder grains. Furthermore, it was found that thermal quenching of Eu 3+ ion emission intensity can be completely suppressed in studied materials by applied pressure. This is due to stronger localization of bound exciton on Eu 3+ ion trap induced by hydrostatic pressure. Furthermore, the effect of 2 MeV oxygen irradiation on the PL properties has been investigated for highly efficient Eu-doped GaN phosphor embedded in KBr-GaN:Eu 3+ composite. Fairly good radiation damage resistance was obtained for 1.7 x 10 12 to 5 x 10 13 cm -2 oxygen fluence. Preliminary data indicate that Eu-doped GaN powder phosphor can be considered for devices in a radiation environment.

  3. Room temperature ferromagnetism in Eu-doped ZnO nanoparticulate powders prepared by combustion reaction method

    International Nuclear Information System (INIS)

    Franco, A.; Pessoni, H.V.S.; Soares, M.P.

    2014-01-01

    Nanoparticulate powders of Eu-doped ZnO with 1.0, 1.5, 2.0 and 3.0 at% Eu were synthesized by combustion reaction method using zinc nitrate, europium nitrate and urea as fuel without subsequent heat treatments. X-ray diffraction patterns (XRD) of all samples showed broad peaks consistent with the ZnO wurtzite structure. The absence of extra reflections in the diffraction patterns ensures the phase purity, except for x=0.03 that exhibits small reflection corresponding to Eu 2 O 3 phase. The average crystallite size determined from the most prominent (1 0 1) peak of the diffraction using Scherrer's equation was in good agreement with those determined by transmission electron microscopy (TEM); being ∼26 nm. The magnetic properties measurements were performed using a vibrating sample magnetometer (VSM) in magnetic fields up to 2.0 kOe at room temperature. The hysteresis loops, typical of magnetic behaviors, indicating that the presence of an ordered magnetic structure can exist in the Eu-doped ZnO wurtzite structure at room temperature. The room temperature ferromagnetism behavior increases with the Eu 3+ doping concentration. All samples exhibited the same Curie temperature (T C ) around ∼726 K, except for x=0.01; T C ∼643 K. High resolution transmission electron microscopy (HRTEM) images revealed defects/strain in the lattice and grain boundaries of Eu-doped ZnO nanoparticulate powders. The origin of room temperature ferromagnetism in Eu-doped ZnO nanoparticulate powders was discussed in terms of these defects, which increase with the Eu 3+ doping concentration. - Highlights: • Room-temperature ferromagnetism. • Structural and magnetic properties of nanoparticulate powders of Zn 1−x Eu x O. • Combustion reaction method

  4. First-principles studies of Ce and Eu doped inorganic scintillator gamma ray detectors

    Science.gov (United States)

    Canning, Andrew; Chaudhry, Anurag; Boutchko, Rostyslav; Derenzo, Stephen

    2011-03-01

    We have performed DFT based band structure calculations for new Ce and Eu doped wide band gap inorganic materials to determine their potential as candidates for gamma ray scintillator detectors. These calculations are based on determining the 4f ground state level of the Ce and Eu relative to the valence band of the host as well as the position of the Ce and Eu 5d excited state relative to the conduction band of the host. Host hole and electron traps as well as STEs (self trapped excitons) can also limit the transfer of energy from the host to the Ce or Eu site and therefore limit the light output. We also present calculations for host hole traps and STEs to compare the energies to the Ce and Eu excited states. The work was supported by the U.S. Department of Homeland Security and carried out at the Lawrence Berkeley National Laboratory under U.S. Department of Energy Contract No. DE-AC02- 05CH11231.

  5. Radioluminescence of red-emitting Eu-doped phosphors for fiberoptic dosimetry

    Energy Technology Data Exchange (ETDEWEB)

    Molina, P.; Santiago, M.; Marcazzo, J.; Caselli, E. [Universidad Nacional del Centro de la Provincia de Buenos Aires, Instituto de Fisica Arroyo Seco, Pinto 399, 7000 Tandil (Argentina); Spano, F. [Autoridad Regulatoria Nuclear, Av. del Libertador 8250, 1429 Buenos Aires (Argentina); Henniger, J. [Institut fur Kern-und Teilchenphysik, Zellescher Weg 19, 01069 Dresden (Germany); Cravero, W., E-mail: pmolina@exa.unicen.edu.ar [Universidad Nacional del Sur, Departamento de Fisica, Av. Colon 80, 8000FTN Bahia Blanca, Buenos Aires (Argentina)

    2011-10-15

    The fiberoptic dosimetry technique (FOD) has become an attractive method for in-vivo real-time dosimetry in radiotherapy. It is based on the use of a tiny piece of scintillator coupled to the end of an optical fiber, which collects the light emitted by the scintillator during irradiation (radioluminescence). Carbon-doped aluminum oxide (Al{sub 2}O{sub 3}:C) is one of the most radioluminescence materials for FOD due to its high efficiency but it presents the drawback of emitting in the spectral region, where spurious luminescence is also important. Spurious luminescence from optical fiber, termed stem effect, is the main problem afflicting FOD. Several techniques have been applied to remove the stem effect. Optical filtering, which consists in using long-pass filters, is the simplest one. This technique is useful when red-emitting scintillators are employed. In this work, the feasibility of using red-emitting Eu-doped phosphors as FOD scintillators has been investigated. (Author)

  6. Cyan-white-red luminescence from europium doped Al2O3-La2O3-SiO2 glasses.

    Science.gov (United States)

    Yang, Hucheng; Lakshminarayana, G; Zhou, Shifeng; Teng, Yu; Qiu, Jianrong

    2008-04-28

    Aluminum-lanthanum-silicate glasses with different Eu doping concentration have been synthesized by conventional melt-quenching method at 1680 degrees C in reductive atmosphere. Under 395nm excitation, samples with low Eu doping concentration show mainly the cyan broad emission at 460nm due to 4f(6)5d(1)-4f(7) transition of Eu(2+); and the samples with higher Eu doping concentration show mainly some narrow emissions with maximum at 616nm due to (5)D(0)-(7)F(j) (J=0, 1, 2, 3, 4) transitions of Eu(3+). Cyan-white-red tunable luminescence under 395nm excitation has been obtained by changing the Eu doping concentration.

  7. Photovoltaic Performance Characterization of Textured Silicon Solar Cells Using Luminescent Down-Shifting Eu-Doped Phosphor Particles of Various Dimensions.

    Science.gov (United States)

    Ho, Wen-Jeng; Deng, Yu-Jie; Liu, Jheng-Jie; Feng, Sheng-Kai; Lin, Jian-Cheng

    2017-01-01

    This paper reports on efforts to enhance the photovoltaic performance of textured silicon solar cells through the application of a layer of Eu-doped silicate phosphor with particles of various dimensions using the spin-on film technique. We examined the surface profile and dimensions of the Eu-doped phosphors in the silicate layer using optical microscopy with J-image software. Optical reflectance, photoluminescence, and external quantum efficiency were used to characterize the luminescent downshifting (LDS) and light scattering of the Eu-doped silicate phosphor layer. Current density-voltage curves under AM 1.5G simulation were used to confirm the contribution of LDS and light scattering produced by phosphor particles of various dimensions. Experiment results reveal that smaller phosphor particles have a more pronounced effect on LDS and a slight shading of incident light. The application of small Eu-doped phosphor particles increased the conversion efficiency by 9.2% (from 12.56% to 13.86%), far exceeding the 5.6% improvement (from 12.54% to 13.32%) achieved by applying a 250 nm layer of SiO₂ and the 4.5% improvement (from 12.37% to 12.98%) observed in cells with large Eu-doped phosphor particles.

  8. Correlation between electronic structure and energy band in Eu-doped CuInTe2 semiconductor compound with chalcopyrite structure

    Institute of Scientific and Technical Information of China (English)

    Tai Wang; Yong-Quan Guo; Shuai Li

    2017-01-01

    The Eu-doped Cu(In,Eu)Te2 semiconductors with chalcopyrite structures are promising materials for their applications in the absorption layer for thin-film solar cells due to their wider band-gaps and better optical properties than those of CulnTe2.In this paper,the Eu-doped CulnTe2 (Culn1-xEuxTe2,x =0,0.1,0.2,0.3) are studied systemically based on the empirical electron theory (EET).The studies cover crystal structures,bonding regularities,cohesive energies,energy levels,and valence electron structures.The theoretical values fit the experimental results very well.The physical mechanism of a broadened band-gap induced by Eu doping into CuInTe2 is the transitions between different hybridization energy levels induced by electron hopping between s and d orbitals and the transformations from the lattice electrons to valence electrons for Cu and In ions.The research results reveal that the photovoltaic effect induces the increase of lattice electrons of In and causes the electric resistivity to decrease.The Eu doping into CuInTe2 mainly influences the transition between different hybridization energy levels for Cu atoms,which shows that the 3d electron numbers of Cu atoms change before and after Eu doping.In single phase CuIn1-xEuxTe2,the number of valence electrons changes regularly with increasing Eu content,and the calculated band gap Eg also increases,which implies that the optical properties of Eu-doped CuIn1-xEuxTe2 are improved.

  9. The Effect of Eu Doping on Microstructure, Morphology and Methanal-Sensing Performance of Highly Ordered SnO2 Nanorods Array

    Directory of Open Access Journals (Sweden)

    Yanping Zhao

    2017-11-01

    Full Text Available Layered Eu-doped SnO2 ordered nanoarrays constructed by nanorods with 10 nm diameters and several hundred nanometers length were synthesized by a substrate-free hydrothermal route using alcohol and water mixed solvent of sodium stannate and sodium hydroxide at 200 °C. The Eu dopant acted as a crystal growth inhibitor to prevent the SnO2 nanorods growth up, resulting in tenuous SnO2 nanorods ordered arrays. The X-ray diffraction (XRD revealed the tetragonal rutile-type structure with a systematic average size reduction and unit cell volume tumescence, while enhancing the residual strain as the Eu-doped content increases. The surface defects that were caused by the incorporation of Eu ions within the surface oxide matrix were observed by high-resolution transmission electron microscope (HRTEM. The results of the response properties of sensors based on the different levels of Eu-doped SnO2 layered nanoarrays demonstrated that the 0.5 at % Eu-doped SnO2 layered nanorods arrays exhibited an excellent sensing response to methanal at 278 °C. The reasons of the enhanced sensing performance were discussed from the complicated defect surface structure, the large specific surface area, and the excellent catalytic properties of Eu dopant.

  10. Structural, morphological and magnetic properties of Eu-doped CoFe2O4 nano-ferrites

    Directory of Open Access Journals (Sweden)

    Aiman Zubair

    Full Text Available Europium (Eu doped spinel cobalt ferrites having composition CoEuxFe2−xO4 where x = 0.00, 0.03, 0.06, 0.09, 0.12 were fabricated by co-precipitation route. In order to observe the phase development of the ferrite samples, thermo-gravimetric analysis was carried out. The synthesized samples were subjected to X-ray diffraction analysis for structural investigation. All the samples were found to constitute face centered cubic (FCC spinel structure belonging to Fd3m space group. Scanning electron microscopy revealed the formation of nanocrystalline grains with spherical shape. Energy dispersive X-ray spectra confirmed the presence of Co, Eu, Fe and O elements with no existence of any impurity. The magnetic hysteresis curves measured at room temperature exhibited ferrimagnetic behavior with maximum saturation magnetization (Ms of 65 emu/g and coercivity (Hc of 966 Oe. The origin of ferrimagnetism in Eu doped cobalt ferrites was discussed in detail with reverence to the allocation of Co2+ and Fe3+ ions within the spinel lattice. The overall coercivity was increased (944–966 Oe and magnetization was decreased (65–46 emu/g with the substitution of Eu3+. The enhancement of former is ascribed to the transition from multi domain to single domain state and reduction in lateral is attributed to the incorporation of nonmagnetic Eu ions for Fe, resulting in weak superexchange interactions. Keywords: Europium doped cobalt ferrites, Co-precipitation, X-ray diffraction, Scanning electron microscopy, Magnetic properties

  11. Moving the Plasmon of LaB₆ from IR to Near-IR via Eu-Doping.

    Science.gov (United States)

    Mattox, Tracy M; Coffman, D Keith; Roh, Inwhan; Sims, Christopher; Urban, Jeffrey J

    2018-02-01

    Lanthanum hexaboride (LaB₆) has become a material of intense interest in recent years due to its low work function, thermal stability and intriguing optical properties. LaB₆ is also a semiconductor plasmonic material with the ability to support strong plasmon modes. Some of these modes uniquely stretch into the infrared, allowing the material to absorb around 1000 nm, which is of great interest to the window industry. It is well known that the plasmon of LaB₆ can be tuned by controlling particle size and shape. In this work, we explore the options available to further tune the optical properties by describing how metal vacancies and Eu doping concentrations are additional knobs for tuning the absorbance from the near-IR to far-IR in La 1-x Eu x B₆ (x = 0, 0.2, 0.5, 0.8, and 1.0). We also report that there is a direct correlation between Eu concentration and metal vacancies within the Eu 1-x La x B₆.

  12. Moving the Plasmon of LaB6 from IR to Near-IR via Eu-Doping

    Directory of Open Access Journals (Sweden)

    Tracy M. Mattox

    2018-02-01

    Full Text Available Lanthanum hexaboride (LaB6 has become a material of intense interest in recent years due to its low work function, thermal stability and intriguing optical properties. LaB6 is also a semiconductor plasmonic material with the ability to support strong plasmon modes. Some of these modes uniquely stretch into the infrared, allowing the material to absorb around 1000 nm, which is of great interest to the window industry. It is well known that the plasmon of LaB6 can be tuned by controlling particle size and shape. In this work, we explore the options available to further tune the optical properties by describing how metal vacancies and Eu doping concentrations are additional knobs for tuning the absorbance from the near-IR to far-IR in La1−xEuxB6 (x = 0, 0.2, 0.5, 0.8, and 1.0. We also report that there is a direct correlation between Eu concentration and metal vacancies within the Eu1−xLaxB6.

  13. Crystal growth and scintillation properties of Ce and Eu doped LiSrAlF{sub 6}

    Energy Technology Data Exchange (ETDEWEB)

    Yamaji, Akihiro, E-mail: yamaji-a@imr.tohoku.ac.jp [Institute of Materials Research, Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai 980-8577 (Japan); Yanagida, Takayuki [New Industry Creation Hatchery Center (NICHe), Tohoku University, 6-6-10 Aoba, Aramaki, Aoba-ku, Sendai 980-8579 (Japan); Kawaguchi, Noriaki [Tokuyama Corporation, Shibuya 3-chome, Shibuya, Tokyo 150-8383 (Japan); Fujimoto, Yutaka; Yokota, Yuui [Institute of Materials Research, Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai 980-8577 (Japan); Watanabe, Kenichi; Yamazaki, Atsushi [Department of Material, Physics and Energy Engineering, Nagoya University, Furo-cho, Chikusa-ku, Nagoya, 464-8603 (Japan); Yoshikawa, Akira [Institute of Materials Research, Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai 980-8577 (Japan); New Industry Creation Hatchery Center (NICHe), Tohoku University, 6-6-10 Aoba, Aramaki, Aoba-ku, Sendai 980-8579 (Japan); Pejchal, Jan [Institute of Physics AS CR, Cukrovarnicka 10, 16200 Prague 6 (Czech Republic)

    2011-12-11

    Ce and Eu doped LiSrAlF{sub 6} (LiSAF) single crystals for the neutron detection with different dopant concentrations were grown by the micro-pulling-down method ({mu}-PD). In Ce:LiSAF, intense emission peaks due to Ce{sup 3+} 5d-4f transitions were observed at approximately 315 and 335 nm in photo- and {alpha}-ray induced radio-luminescence spectra. In case of Eu:LiSAFs, an intense emission peak at 375 nm due to Eu{sup 2+} 5d-4f transition was observed in the radio-luminescence spectra. The pulse height spectra and decay time profiles were measured under {sup 252}Cf neutron irradiation to examine the neutron response. The Ce 3% and Eu 2% doped LiSAF showed the highest light yield of 2860 ph/n with 19 ns main decay time component and 24,000 ph/n with 1610 ns.

  14. Glasses

    DEFF Research Database (Denmark)

    Dyre, Jeppe

    2004-01-01

    The temperature dependence of the viscosity of most glassforming liquids is known to depart significantly from the classical Arrhenius behaviour of simple fluids. The discovery of an unexpected correlation between the extent of this departure and the Poisson ratio of the resulting glass could lead...... to new understanding of glass ageing and viscous liquid dynamics....

  15. Luminescence properties of pure and Eu-doped SrI{sub 2} crystals purified by a “Liquinert” process and grown by vertical Bridgman method

    Energy Technology Data Exchange (ETDEWEB)

    Kawai, Taketoshi, E-mail: buri@p.s.osakafu-u.ac.jp [Osaka Prefecture University, Gakuen-cho 1-1, Naka-ku, Sakai, Osaka 599-8531 (Japan); Sakuragi, Shiro; Hashimoto, Satoshi [Union Materials Inc. 1640 Oshido, Tone-machi, Ibaraki 300-1602 (Japan)

    2016-08-15

    We have prepared high quality crystals of pure SrI{sub 2} and Eu-doped SrI{sub 2} by our original “Liquinert” process and investigated their luminescence properties. Under the excitation with the 193 nm light of an ArF excimer laser, which corresponds to the wavelength above the bandgap of SrI{sub 2} bulk crystals, the pure and Eu doped SrI{sub 2} crystals exhibit no luminescence band related to defects or impurities around 560 nm. This fact indicates that the crystals prepared by the “Liquinert” process contain lower defects and/or impurities. When the Eu-doped SrI{sub 2} crystals are excited with the 325 nm light of a He–Cd laser, only the luminescence band due to the 5d→4f transition in the Eu{sup 2+} ions is observed around 425 nm. The 425 nm band observed at a forward configuration exhibits the shift to the longer wavelength side and the decrease of the luminescence intensity with increasing Eu concentration. The Eu concentration dependences of the peak wavelength and luminescence intensity are simulated on the basis of a simple self-absorption model. - Highlights: • Our original “Liquinert” process allows us to prepare high quality crystals of SrI{sub 2}. • No luminescence band related with impurities and/or defects is observed. • The 425 nm luminescence bands due to Eu{sup 2+} ions are affected by a self-absorption. • A simple self-absorption model reproduces the changes of the 425 nm bands.

  16. Photo- and radio-excited luminescence properties of Eu-doped La2O3–Al2O3 based eutectics

    International Nuclear Information System (INIS)

    Fujimoto, Yutaka; Kamada, Kei; Yanagida, Takayuki; Wakahara, Shingo; Suzuki, Shotaro; Kurosawa, Shunsuke; Yoshikawa, Akira

    2013-01-01

    Eutectic crystal of 0.5% Eu-doped 30LaAlO 3 –70Al 2 O 3 (vol %) was prepared by micro-pulling down (μ-PD) technique under nitrogen atmosphere. Being excited at a wavelength of 320 nm, the crystal exhibited intense emission band with a maximum at 450 nm which is corresponding to 4f 6 5d-4f 7 ( 8 S 7/2 ) transitions of Eu 2+ . The decay time and fluorescence quantum efficiency (QE) were determined to be about 475 ns and 60%, respectively. When alpha-ray excited the crystal, both Eu 2+ 4f 6 5d-4f 7 ( 8 S 7/2 ) and Eu 3+ 4f 6 -4f 6 ( 5 D 0 - 7 F 1,2 ) emission peaks were observed at 435 nm and 600 nm. By the pulse height spectra, the relative scintillation light yield of the crystal was about 4% compared with that of BGO commercial scintillator. -- Highlights: •0.5% Eu-doped 30LaAlO 3 –70Al 2 O 3 eutectic crystal was grown by μ-PD technique. •The crystal showed intense Eu 2+ 5d-4f emission at 450 nm under excited at 320 nm. •The fluorescence quantum efficiency was calculated to be about 60%. •The scintillation light yield was about 4% compared with that of BGO scintillator

  17. Structural, electric and dielectric properties of Eu-doped SrBi2Nb2O9 ceramics obtained by co-precipitation route

    Directory of Open Access Journals (Sweden)

    Mohamed Afqir

    2018-03-01

    Full Text Available This paper presents a study of the structure and dielectric properties of Eu-doped SrBi2Nb2O9 ceramics prepared by co-precipitation route and sintered at 850 °C. The materials were examined using XRD and FTIR methods. XRD data indicated the formation of well crystallized structure of the pure and doped SrBi2Nb2O9, without the presence of undesirable phases. FTIR spectra do not bring a significant shift in the band positions. Moreover, the AC conductivity, dielectric constant and dielectric loss of the ceramics were determined through the frequency range [50 kHz–1 MHz]. In particular, the dielectric constant (ε′ and dielectric losses (tan δ of the SrBi2Nb2O9 and SrBi1.6Eu0.4Nb2O9 ceramics were measured as a function of temperature at various frequencies.

  18. Optically active centers in Eu implanted, Eu in situ doped GaN, and Eu doped GaN quantum dots

    International Nuclear Information System (INIS)

    Bodiou, L.; Braud, A.; Doualan, J.-L.; Moncorge, R.; Park, J. H.; Munasinghe, C.; Steckl, A. J.; Lorenz, K.; Alves, E.; Daudin, B.

    2009-01-01

    A comparison is presented between Eu implanted and Eu in situ doped GaN thin films showing that two predominant Eu sites are optically active around 620 nm in both types of samples with below and above bandgap excitation. One of these sites, identified as a Ga substitutional site, is common to both types of Eu doped GaN samples despite the difference in the GaN film growth method and in the doping technique. High-resolution photoluminescence (PL) spectra under resonant excitation reveal that in all samples these two host-sensitized sites are in small amount compared to the majority of Eu ions which occupy isolated Ga substitutional sites and thus cannot be excited through the GaN host. The relative concentrations of the two predominant host-sensitized Eu sites are strongly affected by the annealing temperature for Eu implanted samples and by the group III element time opening in the molecular beam epitaxy growth. Red luminescence decay characteristics for the two Eu sites reveal different excitation paths. PL dynamics under above bandgap excitation indicate that Eu ions occupying a Ga substitutional site are either excited directly into the 5 D 0 level or into higher excited levels such as 5 D 1 , while Eu ions sitting in the other site are only directly excited into the 5 D 0 level. These differences are discussed in terms of the spectral overlap between the emission band of a nearby bound exciton and the absorption bands of Eu ions. The study of Eu doped GaN quantum dots reveals the existence of only one type of Eu site under above bandgap excitation, with Eu PL dynamics features similar to Eu ions in Ga substitutional sites

  19. High-Throughput Synthesis and Characterization of Eu Doped Ba xSr2- xSiO4 Thin Film Phosphors.

    Science.gov (United States)

    Frost, Sara; Guérin, Samuel; Hayden, Brian E; Soulié, Jean-Philippe; Vian, Chris

    2018-06-20

    High-throughput techniques have been employed for the synthesis and characterization of thin film phosphors of Eu-doped Ba x Sr 2- x SiO 4 . Direct synthesis from evaporation of the constituent elements under a flux of atomic oxygen on a sapphire substrate at 850 °C was used to directly produce thin film libraries (415 nm thickness) of the crystalline orthosilicate phase with the desired compositional variation (0.24 > x > 1.86). The orthosilicate phase could be synthesized as a pure, or predominantly pure, phase. Annealing the as synthesized library in a reducing atmosphere resulted in the reduction of the Eu while retaining the orthosilicate phase, and resulted in a materials thin film library where fluorescence excited by blue light (450 nm) was observable by the naked eye. Parallel screening of the fluorescence from the combinatorial libraries of Eu doped Ba x Sr 2- x SiO 4 has been implemented by imaging the fluorescent radiation over the library using a monochrome digital camera using a series of color filters. Informatics tools have been developed to allow the 1931 CIE color coordinates and the relative quantum efficiencies of the materials library to be rapidly assessed and mapped against composition, crystal structure and phase purity. The range of compositions gave values of CIE x between 0.17 and 0.52 and CIE y between 0.48 and 0.69 with relative efficiencies in the range 2.0 × 10 -4 -7.6 × 10 -4 . Good agreement was obtained between the thin film phosphors and the fluorescence characteristics of a number of corresponding bulk phosphor powders. The thermal quenching of fluorescence in the thin film libraries was also measured in the temperature range 25-130 °C: The phase purity of the thin film was found to significantly influence both the relative quantum efficiency and the thermal quenching of the fluorescence.

  20. Barium halide nanocrystals in fluorozirconate based glass ceramics for scintillation application

    International Nuclear Information System (INIS)

    Selling, J.

    2007-01-01

    Europium (Eu)-activated barium halide nanocrystals in fluorozirconate based glass ceramics represent a promising class of Xray scintillators. The scintillation in these glass ceramics is mainly caused by the emission of divalent Eu incorporated in hexagonal BaCl 2 nanocrystals which are formed in the glass matrix upon appropriate annealing. Experiments with cerium (Ce)-activated fluorozironate glass ceramics showed that Ce is an interesting alternative. In order to get a better understanding of the scintillation mechanism in Eu- or Ce-activated barium halide nanocrystals, an investigation of the processes in the corresponding bulk material is essential. The objective of this thesis is the investigation of undoped, Eu-, and Ce-doped barium halides by X-ray excited luminescence (XL), pulse height, and scintillation decay spectra. That will help to figure out which of these crystals has the most promising scintillation properties and would be the best nanoparticles for the glass ceramics. Furthermore, alternative dopants like samarium (Sm) and manganese (Mn) were also investigated. Besides the above-mentioned optical investigation electron paramagnetic resonance (EPR) and Moessbauer measurements were carried out in order to complete the picture of Eu-doped barium halides. The EPR data of Eu-doped BaI 2 is anticipated to yield more information about the crystal field and crystal structure that will help to understand the charge carrier process during the scintillation process. The main focus of the Moessbauer investigations was set on the Eu-doped fluorochlorozirconate glass ceramics. The results of this investigation should help to improve the glass ceramics. The Eu 2+ /Eu 3+ ratio in the glass ceramics should be determined and optimize favor of the Eu 2+ . We also want to distinguish between Eu 2+ in the glass matrix and Eu 2+ in the nanocrystals. For a better understanding of Moessbauer spectroscopy on Eu also measurements on Eu in a CaF 2 host lattice were carried

  1. Optical, Structural and Paramagnetic Properties of Eu-Doped Ternary Sulfides ALnS2 (A = Na, K, Rb; Ln = La, Gd, Lu, Y

    Directory of Open Access Journals (Sweden)

    Vítězslav Jarý

    2015-10-01

    Full Text Available Eu-doped ternary sulfides of general formula ALnS2 (A = Na, K, Rb; Ln = La, Gd, Lu, Y are presented as a novel interesting material family which may find usage as X-ray phosphors or solid state white light emitting diode (LED lighting. Samples were synthesized in the form of transparent crystalline hexagonal platelets by chemical reaction under the flow of hydrogen sulfide. Their physical properties were investigated by means of X-ray diffraction, time-resolved photoluminescence spectroscopy, electron paramagnetic resonance, and X-ray excited fluorescence. Corresponding characteristics, including absorption, radioluminescence, photoluminescence excitation and emission spectra, and decay kinetics curves, were measured and evaluated in a broad temperature range (8–800 K. Calculations including quantum local crystal field potential and spin-Hamiltonian for a paramagnetic particle in D3d local symmetry and phenomenological model dealing with excited state dynamics were performed to explain the experimentally observed features. Based on the results, an energy diagram of lanthanide energy levels in KLuS2 is proposed. Color model xy-coordinates are used to compare effects of dopants on the resulting spectrum. The application potential of the mentioned compounds in the field of white LED solid state lighting or X-ray phosphors is thoroughly discussed.

  2. Photoemission properties of Eu-doped Zr1- x Ce x O2 (x = 0-0.2) nanoparticles prepared by hydrothermal method

    Science.gov (United States)

    Ozawa, Masakuni; Matsumoto, Masashi; Hattori, Masatomo

    2018-01-01

    Photoluminescent Eu-doped ZrO2 and Zr1- x Ce x O2 (x = 0-0.2) nanoparticles were prepared by a hydrothermal method. X-ray diffraction and Raman spectra indicated the formation of tetragonal crystals of ZrO2 and its solid solutions with a grain size of less than 10 nm diameter after heat treatment at 400 °C. The photoemission spectra of Zr1- x Ce x O2:Eu3+ nanocrystalline samples showed the typical emission of Eu3+ ions assigned to 5D0 → 7F1 (590 nm) and 5D0 → 7F2 (610 nm) transitions and additional emissions of 5D0 → 7F J with higher J of 3-5. Increasing the CeO2 concentration reduced the emission intensity, and the emission peak shift was affected by a local lattice distortion, i.e., CeO2 concentration. The present study provided fundamental knowledge that is expected to enable the fabrication of ZrO2-based nanocrystal phosphor materials and a measure for controlling the emission peak shift and intensity in oxide fluorite-based phosphor.

  3. Controllable synthesis of Ln3+ (Ln = Tb, Eu) doped zinc phosphate nano-/micro-structured materials: phase, morphology and luminescence properties

    Science.gov (United States)

    Yue, Dan; Lu, Wei; Li, Chunyang; Zhang, Xinlei; Liu, Chunxia; Wang, Zhenling

    2014-01-01

    Ln3+ (Ln = Tb, Eu) doped zinc phosphate tetrahydrate (ZPT:Ln3+) and ammonium zinc phosphate (AZP:Ln3+) nano-/micro-structured materials were synthesized in aqueous solution without the addition of any structure-directing agent. The phase structures, morphologies and luminescence properties of the as-synthesized samples were investigated by X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDX), transmission electron microscopy (TEM), photoluminescence (PL) spectroscopy and lifetime. These investigations indicate that different phosphate sources MnH(3-n)PO4 (M = NH4+ or Na+, n = 1, 2, 3) can lead to the altering of morphology from nanosheet to microflower, but have no significant effect on the phase structure of the samples. The microlump, nanosheet, and microflower (constructed by the primary microlumps or nanosheets) of orthorhombic ZPT:Ln3+ could be selectively prepared by adjusting the pH value from 3.5 to 7.0. A mixture of orthorhombic ZPT:Ln3+ and monoclinic AZP:Ln3+ with a microflower morphology was obtained when the pH value was adjusted to 8.0. Monoclinic AZP:Ln3+ microplate, microcube and nanoparticle morphologies were obtained at pH values of 8.5, 9.0 and 11.0 respectively. The phase transformation and growth mechanism of the diverse morphologies were proposed, and ZPT:Ln3+ (Ln3+ = Eu or Tb) samples exhibit red or green emission under the excitation of UV light.Ln3+ (Ln = Tb, Eu) doped zinc phosphate tetrahydrate (ZPT:Ln3+) and ammonium zinc phosphate (AZP:Ln3+) nano-/micro-structured materials were synthesized in aqueous solution without the addition of any structure-directing agent. The phase structures, morphologies and luminescence properties of the as-synthesized samples were investigated by X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDX), transmission electron microscopy (TEM), photoluminescence (PL) spectroscopy and lifetime. These

  4. Low-temperature synthesis, phonon and luminescence properties of Eu doped Y{sub 3}Al{sub 5}O{sub 12} (YAG) nanopowders

    Energy Technology Data Exchange (ETDEWEB)

    Mączka, M., E-mail: m.maczka@int.pan.wroc.pl [Institute of Low Temperature and Structure Research, Polish Academy of Sciences, P.O. Box 1410, 50-950 Wrocław 2 (Poland); Bednarkiewicz, A. [Institute of Low Temperature and Structure Research, Polish Academy of Sciences, P.O. Box 1410, 50-950 Wrocław 2 (Poland); Mendoza-Mendoza, E.; Fuentes, A.F. [Cinvestav Unidad Saltillo, Apartado Postal 663, 25000 Saltillo, Coahuila (Mexico); Kępiński, L. [Institute of Low Temperature and Structure Research, Polish Academy of Sciences, P.O. Box 1410, 50-950 Wrocław 2 (Poland)

    2014-02-14

    This contribution presents two simple and cost-effective routes for the low-temperature and large-scale production of pure and Eu-doped Y{sub 3}Al{sub 5}O{sub 12} (yttrium aluminum garnet YAG) nanopowders. The proposed methodologies combine a mechanically assisted metathesis reaction or coprecipitation from solution followed by crystallization of the obtained precursors from molten sodium nitrate/nitrite. Both procedures allow obtaining pure and/or doped YAG nanopowders at remarkably low temperatures, i.e. already at 350 °C although firing at 500 °C is needed in order to get single phase and fully crystalline materials. As-obtained samples were characterized by XRD, TEM, Raman, IR and luminescence methods. These methods showed that the mean crystallite size is near 23–31 and 51 nm, when crystallization is performed from the amorphous precursor obtained by a mechanically assisted metathesis reaction and coprecipitation, respectively. Raman and IR spectra indicated better crystallinity of the powders prepared at 500 °C. The emission study showed that the intensity ratio between hypersensitive {sup 5}D{sub 0} → {sup 7}F{sub 2} and magnetic-dipole {sup 5}D{sub 0} → {sup 7}F{sub 1} transitions of Eu{sup 3+} is significantly larger than expected for well-crystallized YAG. Origin of this behavior is discussed. - Highlights: • Nanoparticles of Y{sub 3}Al{sub 5}O{sub 12} (YAG) and YAG:Eu{sup 3+} have been prepared at remarkable 350 °C. • Metathesis/molten salts and coprecipitation/molten salts methods were used. • Metathesis/molten salts method is suitable for preparation of rare-earth doped YAG. • Emission properties of YAG:Eu{sup 3+} are significantly different from bulk YAG.

  5. Barium halide nanocrystals in fluorozirconate based glass ceramics for scintillation application

    Energy Technology Data Exchange (ETDEWEB)

    Selling, J.

    2007-07-01

    Europium (Eu)-activated barium halide nanocrystals in fluorozirconate based glass ceramics represent a promising class of Xray scintillators. The scintillation in these glass ceramics is mainly caused by the emission of divalent Eu incorporated in hexagonal BaCl{sub 2} nanocrystals which are formed in the glass matrix upon appropriate annealing. Experiments with cerium (Ce)-activated fluorozironate glass ceramics showed that Ce is an interesting alternative. In order to get a better understanding of the scintillation mechanism in Eu- or Ce-activated barium halide nanocrystals, an investigation of the processes in the corresponding bulk material is essential. The objective of this thesis is the investigation of undoped, Eu-, and Ce-doped barium halides by X-ray excited luminescence (XL), pulse height, and scintillation decay spectra. That will help to figure out which of these crystals has the most promising scintillation properties and would be the best nanoparticles for the glass ceramics. Furthermore, alternative dopants like samarium (Sm) and manganese (Mn) were also investigated. Besides the above-mentioned optical investigation electron paramagnetic resonance (EPR) and Moessbauer measurements were carried out in order to complete the picture of Eu-doped barium halides. The EPR data of Eu-doped BaI{sub 2} is anticipated to yield more information about the crystal field and crystal structure that will help to understand the charge carrier process during the scintillation process. The main focus of the Moessbauer investigations was set on the Eu-doped fluorochlorozirconate glass ceramics. The results of this investigation should help to improve the glass ceramics. The Eu{sup 2+}/Eu{sup 3+} ratio in the glass ceramics should be determined and optimize favor of the Eu{sup 2+}. We also want to distinguish between Eu{sup 2+} in the glass matrix and Eu{sup 2+} in the nanocrystals. For a better understanding of Moessbauer spectroscopy on Eu also measurements on Eu in a

  6. Color-converted remote phosphor prototype of a multiwavelength excitable borosilicate glass for white light-emitting diodes

    International Nuclear Information System (INIS)

    Tian Hua; Qiu Kun; Song Jun; Wang Da-Jian; Liu Ji-Wen

    2012-01-01

    We report a unique red light-emitting Eu-doped borosilicate glass to convert color for warm white light-emitting diodes. This glass can be excited from 394 nm-peaked near ultraviolet light, 466 nm-peaked blue light, to 534 nm-peaked green light to emit the desired red light with an excellent transmission in the wavelength range of 400–700 nm which makes this glass suitable for color conversion without a great cost of luminous power loss. In particular, when assembling this glass for commercial white light-emitting diodes, the tested results show that the color rendering index is improved to 84 with a loss of luminous power by 12 percent at average, making this variety of glass promising for inorganic “remote-phosphor” color conversion

  7. Direct transparent electrode patterning on layered GaN substrate by screen printing of indium tin oxide nanoparticle ink for Eu-doped GaN red light-emitting diode

    International Nuclear Information System (INIS)

    Kashiwagi, Y.; Yamamoto, M.; Saitoh, M.; Takahashi, M.; Ohno, T.; Nakamoto, M.; Koizumi, A.; Fujiwara, Y.; Takemura, Y.; Murahashi, K.; Ohtsuka, K.; Furuta, S.

    2014-01-01

    Transparent electrodes were formed on Eu-doped GaN-based red-light-emitting diode (GaN:Eu LED) substrates by the screen printing of indium tin oxide nanoparticle (ITO np) inks as a wet process. The ITO nps with a mean diameter of 25 nm were synthesized by the controlled thermolysis of a mixture of indium complexes and tin complexes. After the direct screen printing of ITO np inks on GaN:Eu LED substrates and sintering at 850 °C for 10 min under atmospheric conditions, the resistivity of the ITO film was 5.2 mΩ cm. The fabricated LED up to 3 mm square surface emitted red light when the on-voltage was exceeded

  8. Direct transparent electrode patterning on layered GaN substrate by screen printing of indium tin oxide nanoparticle ink for Eu-doped GaN red light-emitting diode

    Science.gov (United States)

    Kashiwagi, Y.; Koizumi, A.; Takemura, Y.; Furuta, S.; Yamamoto, M.; Saitoh, M.; Takahashi, M.; Ohno, T.; Fujiwara, Y.; Murahashi, K.; Ohtsuka, K.; Nakamoto, M.

    2014-12-01

    Transparent electrodes were formed on Eu-doped GaN-based red-light-emitting diode (GaN:Eu LED) substrates by the screen printing of indium tin oxide nanoparticle (ITO np) inks as a wet process. The ITO nps with a mean diameter of 25 nm were synthesized by the controlled thermolysis of a mixture of indium complexes and tin complexes. After the direct screen printing of ITO np inks on GaN:Eu LED substrates and sintering at 850 °C for 10 min under atmospheric conditions, the resistivity of the ITO film was 5.2 mΩ cm. The fabricated LED up to 3 mm square surface emitted red light when the on-voltage was exceeded.

  9. Direct transparent electrode patterning on layered GaN substrate by screen printing of indium tin oxide nanoparticle ink for Eu-doped GaN red light-emitting diode

    Energy Technology Data Exchange (ETDEWEB)

    Kashiwagi, Y., E-mail: kasiwagi@omtri.or.jp; Yamamoto, M.; Saitoh, M.; Takahashi, M.; Ohno, T.; Nakamoto, M. [Osaka Municipal Technical Research Institute, 1-6-50 Morinomiya, Joto-ku, Osaka 536-8553 (Japan); Koizumi, A.; Fujiwara, Y. [Division of Materials and Manufacturing Science, Graduate School of Engineering, Osaka University, 2-1 Yamadaoka, Suita, Osaka 565-0871 (Japan); Takemura, Y.; Murahashi, K.; Ohtsuka, K. [Okuno Chemical Industries Co., Ltd., 2-1-25 Hanaten-nishi, Joto-ku, Osaka 536-0011 (Japan); Furuta, S. [Tomoe Works Co., Ltd., 7-13 Tsurumachi, Amagasaki 660-0092 (Japan)

    2014-12-01

    Transparent electrodes were formed on Eu-doped GaN-based red-light-emitting diode (GaN:Eu LED) substrates by the screen printing of indium tin oxide nanoparticle (ITO np) inks as a wet process. The ITO nps with a mean diameter of 25 nm were synthesized by the controlled thermolysis of a mixture of indium complexes and tin complexes. After the direct screen printing of ITO np inks on GaN:Eu LED substrates and sintering at 850 °C for 10 min under atmospheric conditions, the resistivity of the ITO film was 5.2 mΩ cm. The fabricated LED up to 3 mm square surface emitted red light when the on-voltage was exceeded.

  10. Microstructures and luminescent properties of Ce-doped transparent mica glass-ceramics

    International Nuclear Information System (INIS)

    Taruta, Seiichi; Iwasaki, Yoshitomo; Nishikiori, Hiromasa; Yamakami, Tomohiko; Yamaguchi, Tomohiro; Kitajima, Kunio; Okada, Kiyoshi

    2012-01-01

    Highlights: ► Ce-doped transparent glass-ceramics and their parent glasses. ► TEM and STEM images for the microstructures. ► Each mica crystal did not contain Ce uniformly. ► Emission due to Ce 3+ ions in the glass phase and/or Ce 3+ ions in the mica crystals. - Abstract: Transparent mica glass-ceramics were prepared by heating parent glasses that had been doped with 0.5–15 mol% CeO 2 . During the melting and heat treatment, Ce 4+ ions in the specimens were reduced to Ce 3+ ions, and one or both of these ion species were then replaced with Li + ions in the interlayers of the separated mica crystals. However, scanning transmission electron microscope (STEM) and Z-contrast imaging revealed that the mica crystals did not contain the same amount of Ce. On excitation at 254 nm, the parent glasses and glass-ceramics emitted blue light, which originated from the 5d to 4f transition of the Ce 3+ ions. The emission of the glass-ceramic containing a smaller amount of Ce was attributed to the Ce 3+ ions in both the glass phase and the mica crystals, whereas that of the glass-ceramics containing a larger amount of Ce was caused mainly by Ce 3+ ions in the mica crystals. The dependence of the emission band of the parent glasses on the amount of Ce was a unique feature of the Ce-doped transparent mica glass-ceramics and was not observed in previous studies of Eu-doped parent glasses and mica glass-ceramics.

  11. Structure, luminescence and thermal quenching properties of Eu doped Sr{sub 2−x}Ba{sub x}Si{sub 5}N{sub 8} red phosphors

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Y.H.; Chen, L.; Zhou, X.F.; Liu, R.H., E-mail: griremlrh@126.com; Zhuang, W.D.

    2017-02-15

    Eu{sup 2+} doped Sr{sub 2-x}Ba{sub x}Si{sub 5}N{sub 8} phosphors were synthesized at 1610 ℃ for 4 h via the solid-state reaction method. The XRD results confirm that the complete solid solutions are formed. With the increase of x, the emission spectra show an obvious blue-shift from 610 nm to 585 nm under the excitation of 460 nm. The color tone can be tuned from yellow to red. The corresponding mechanism for the blue-shift of peak-wavelength is studied in detail. The results of decomposed Gaussian spectra and fluorescence lifetime show that the local coordination structure surrounding activator ions changes with increasing x value. It is found that the probability of Eu occupying Sr1 and Sr2 site is dependent on Ba/Sr ratio. The variation of thermal quenching properties and the corresponding mechanism is discussed in detail. The results indicate that Eu{sup 2+} doped Sr{sub 2-x}Ba{sub x}Si{sub 5}N{sub 8} is a promising orange red-emitting phosphor for near UV or blue light-pumped white light-emitting-diodes (wLEDs). - Graphical abstract: Eu{sup 2+} doped Sr{sub 2-x}Ba{sub x}Si{sub 5}N{sub 8} solid solutions were prepared by the solid-state reaction method. The structure, luminescence and thermal quenching properties with varying Ba/Sr ratio were investigated in detail. - Highlights: • The stucture and luminescence properties of Eu doped Sr{sub 2-x}Ba{sub x}Si{sub 5}N{sub 8} phosphors were investigated. • The samples with the intermediate compositions(x=1.0,1.5) show better stability than the end members of both Sr{sub 2}Si{sub 5}N{sub 8}:Eu{sup 2+} and Ba{sub 2}Si{sub 5}N{sub 8}:Eu{sup 2+}. • The possible mechanism for the improvement of thermal quenching properties was proposed.

  12. Spectroscopic Studies of the Behavior of Eu3+ on the Luminescence of Cadmium Tellurite Glasses

    Directory of Open Access Journals (Sweden)

    I. V. García-Amaya

    2015-01-01

    Full Text Available The effect of europium doping on the photoluminescence of ZnO-CdO-TeO2 glasses is analyzed. TeO2-based glasses are of high interest as hosts for laser glasses. The Eu-doped oxide glasses were prepared by the conventional melt-quenching method. Five different concentrations of europium nitrate hexahydrate that varied from 0.3 to 1.5 mol% were used. SEM observations revealed the formation of zinc aluminate spinel and disperse droplets of liquid-liquid phase separation in the glasses. X-Ray diffraction reveals the amorphous structure of the fabricated glasses. FT-IR and Raman spectra show the presence of TeO4 and TeO3+1/TeO3 units that conform with the glass matrix. Raman spectra evidenced a band located at 1556 cm−1 that can be related to interstitial molecular oxygen in the glass matrix. Photoluminescence of the glasses showed light emission due to the following europiumtransitions from its D52, D51, and D50 levels to its F7J manifolds: D52→F70 (468 nm, D52→F72 (490 nm, D52→F73 (511 nm, D51→F71 (536 nm, D51→F72 (554 nm, D50→F70 (579.5 nm, D50→F71 (592 nm, D50→F72 (613 nm, D50→F73 (652 nm, and D50→F74 (490 nm. The estimated decay time, τ, was 0.4 ms for all the glasses.

  13. Optical Characterization of Nano- and Microcrystals of EuPO₄ Created by One-Step Synthesis of Antimony-Germanate-Silicate Glass Modified by P₂O₅.

    Science.gov (United States)

    Zmojda, Jacek; Kochanowicz, Marcin; Miluski, Piotr; Baranowska, Agata; Pisarski, Wojciech A; Pisarska, Joanna; Jadach, Renata; Sitarz, Maciej; Dorosz, Dominik

    2017-09-09

    Technology of active glass-ceramics (GC) is an important part of luminescent materials engineering. The classic method to obtain GC is based on annealing of parent glass in proper temperature and different time periods. Generally, only the bulk materials are investigated as a starting host for further applications. However, the effect of an additional heat-treatment process on emission and structural properties during GC processing is omitted. Here, we focus on the possibility of obtaining transparent glass-ceramic doped with europium ions directly with a melt-quenching method. The influence of phosphate concentration (up to 10 mol %) on the inversion symmetry of local environment of Eu 3+ ions in antimony-germanate-silicate (SGS) glass has been investigated. The Stark splitting of luminescence spectra and the local asymmetry ratio estimated by relation of (⁵D₀→⁷F₂)/(⁵D₀→⁷F₁) transitions in fabricated glass confirms higher local symmetry around Eu 3+ ions. Based on XRD and SEM/EDX measurements, the EuPO₄ nano- and microcrystals with monoclinic geometry were determined. Therefore, in our experiment, we confirmed possibility of one-step approach to fabricate crystalline structures (glass-ceramic) in Eu-doped SGS glass without additional annealing process.

  14. Effect of structural evolution of ZnO/HfO2 nanocrystals on Eu2+/Eu3+ emission in glass-ceramic waveguides for photonic applications.

    Science.gov (United States)

    Ghosh, Subhabrata; Bhaktha B N, Shivakiran

    2018-06-01

    Eu-doped 70SiO 2 -23HfO 2 -7ZnO (mol%) glass-ceramic waveguides have been fabricated by sol-gel method as a function of heat-treatment temperatures for on-chip blue-light emitting source applications. Structural evolution of spherical ZnO and spherical as well as rod-like HfO 2 nanocrystalline structures have been observed with heat-treatments at different temperatures. Initially, in the as-prepared samples at 900 ◦ C, both, Eu 2+ as well as Eu 3+ ions are found to be present in the ternary matrix. With controlled heat-treatments of up to 1000 ◦ C for 2 h, local environment of Eu-ions become more crystalline in nature and the reduction of Eu 3+ to Eu 2+ takes place in such ZnO/HfO 2 crystalline environments. In these ternary glass-ceramic waveguides, heat-treated at higher temperatures, the blue-light emission characteristic, which is the signature of 4f 6 5d [Formula: see text] 4f 7 energy level transition of Eu 2+ ions is found to be greatly enhanced. The as-prepared glass-ceramic waveguides exhibit a propagation loss of 0.4 ± 0.2 dB cm -1 at 632.8 nm. Though the propagation losses increase with the growth of nanocrystals, the added functionalities achieved in the optimally heat-treated Eu-doped 70SiO 2 -23HfO 2 -7ZnO (mol%) waveguides, make them a viable functional optical material for the fabrication of on-chip blue-light emitting sources for integrated optic applications.

  15. Effect of structural evolution of ZnO/HfO2 nanocrystals on Eu2+/Eu3+ emission in glass-ceramic waveguides for photonic applications

    Science.gov (United States)

    Ghosh, Subhabrata; N, Shivakiran Bhaktha B.

    2018-06-01

    Eu-doped 70SiO2–23HfO2–7ZnO (mol%) glass-ceramic waveguides have been fabricated by sol-gel method as a function of heat-treatment temperatures for on-chip blue-light emitting source applications. Structural evolution of spherical ZnO and spherical as well as rod-like HfO2 nanocrystalline structures have been observed with heat-treatments at different temperatures. Initially, in the as-prepared samples at 900 ◦C, both, Eu2+ as well as Eu3+ ions are found to be present in the ternary matrix. With controlled heat-treatments of up to 1000 ◦C for 2 h, local environment of Eu-ions become more crystalline in nature and the reduction of Eu3+ to Eu2+ takes place in such ZnO/HfO2 crystalline environments. In these ternary glass-ceramic waveguides, heat-treated at higher temperatures, the blue-light emission characteristic, which is the signature of 4f 65d \\to 4f 7 energy level transition of Eu2+ ions is found to be greatly enhanced. The as-prepared glass-ceramic waveguides exhibit a propagation loss of 0.4 ± 0.2 dB cm‑1 at 632.8 nm. Though the propagation losses increase with the growth of nanocrystals, the added functionalities achieved in the optimally heat-treated Eu-doped 70SiO2–23HfO2–7ZnO (mol%) waveguides, make them a viable functional optical material for the fabrication of on-chip blue-light emitting sources for integrated optic applications.

  16. Glass sealing

    Energy Technology Data Exchange (ETDEWEB)

    Brow, R.K.; Kovacic, L.; Chambers, R.S. [Sandia National Labs., Albuquerque, NM (United States)

    1996-04-01

    Hernetic glass sealing technologies developed for weapons component applications can be utilized for the design and manufacture of fuel cells. Design and processing of of a seal are optimized through an integrated approach based on glass composition research, finite element analysis, and sealing process definition. Glass sealing procedures are selected to accommodate the limits imposed by glass composition and predicted calculations.

  17. Electrochromic Glasses.

    Science.gov (United States)

    1980-07-31

    this glass and that dipole-dipole correlations contribute to the "ferroelectric-like" character of this amorphous system. The TeO2 -W03 glasses can only...shows the dielectric constant and Fig. I(b) glass from pure TeO2 ot pure WO. In addition, glass the tan 8 of the WO glass as a function of temperature... glasses containing WO, in various glass forming nitworks of LifO-B1O0, Na:O-BzO,, and TeO2 were prepared from reagent grade oxides at 800 C - 9SO C in

  18. Preparation method and thermal properties of samarium and europium-doped alumino-phosphate glasses

    Energy Technology Data Exchange (ETDEWEB)

    Sava, B.A., E-mail: savabogdanalexandru@yahoo.com [National Institute of Research and Development for Optoelectronics, Department for Optospintronics, 409 Atomistilor Street, P.O. Box MG – 5, RO-77125 Magurele (Romania); Elisa, M., E-mail: astatin18@yahoo.com [National Institute of Research and Development for Optoelectronics, Department for Optospintronics, 409 Atomistilor Street, P.O. Box MG – 5, RO-77125 Magurele (Romania); Boroica, L., E-mail: boroica_lucica@yahoo.com [National Institute for Lasers, Plasma and Radiation Physics, 77125 Magurele (Romania); Monteiro, R.C.C., E-mail: rcm@fct.unl.pt [Center of Materials Research/Institute for Nanostructures, Nanomodelling and Nanofabrication, (CENIMAT/I3N), Department of Materials Sciences, Faculty of Sciences and Technology, Universidade Nova de Lisboa, 2829-516 Caparica (Portugal)

    2013-12-01

    Highlights: • Improved preparation method of rare-earth-doped phosphate glasses was done. • Working and annealing temperatures were lower than for undoped phosphate glass. • Doped glass viscosity is also lower and has quasi-linear variation with temperature. • Exothermic peak appears at about 555 °C and 685 °C, due to devitrification in glass. -- Abstract: The present work investigates alumino-phosphate glasses from Li{sub 2}O–BaO–Al{sub 2}O{sub 3}–La{sub 2}O{sub 3}–P{sub 2}O{sub 5} system containing Sm{sup 3+} and Eu{sup 3+} ions, prepared by two different ways: a wet raw materials mixing route followed by evaporation and melt-quenching, and by remelting of shards. The linear thermal expansion coefficient measured by dilatometry is identical for both rare-earth-doped phosphate glasses. Comparatively to undoped phosphate glass the linear thermal expansion coefficient increases with 2 × 10{sup −7} K{sup −1} when dopants are added. The characteristic temperatures very slowly decrease but can be considered constant with atomic weight, atomic number and f electrons number of the doping ions in the case of T{sub g} (vitreous transition temperature) and T{sub sr} (high annealing temperature) but slowly increase in the case of T{sub ir} (low annealing temperature–strain point) and very slowly increase, being practically constant in the case of T{sub D} (dilatometric softening temperature). Comparatively to undoped phosphate glass the characteristic temperatures of Sm and Eu-doped glasses present lower values. The higher values of electrical conductance for both doped glasses, comparatively to usual soda-lime-silicate glass, indicate a slightly reduced stability against water. The viscosity measurements, showed a quasi-linear variation with temperature the mean square deviation (R{sup 2}) being ranged between 0.872% and 0.996%. The viscosity of doped glasses comparatively to the undoped one is lower at the same temperature. Thermogravimetric

  19. Glass consistency and glass performance

    International Nuclear Information System (INIS)

    Plodinec, M.J.; Ramsey, W.G.

    1994-01-01

    Glass produced by the Defense Waste Processing Facility (DWPF) will have to consistently be more durable than a benchmark glass (evaluated using a short-term leach test), with high confidence. The DWPF has developed a Glass Product Control Program to comply with this specification. However, it is not clear what relevance product consistency has on long-term glass performance. In this report, the authors show that DWPF glass, produced in compliance with this specification, can be expected to effectively limit the release of soluble radionuclides to natural environments. However, the release of insoluble radionuclides to the environment will be limited by their solubility, and not glass durability

  20. Colloidal glasses

    Indian Academy of Sciences (India)

    First page Back Continue Last page Overview Graphics. Colloidal glasses. Glassy state is attained when system fails to reach equilibrium due to crowding of constituent particles. In molecular glasses, glassy state is reached by rapidly lowering the temperature. In colloidal glasses, glassy state is reached by increasing the ...

  1. Energy transfer induced Eu{sup 3+} photoluminescence enhancement in tellurite glass

    Energy Technology Data Exchange (ETDEWEB)

    Stambouli, W. [Laboratoire des Materiaux Mineraux et leurs Applications, Centre National de Recherches en Sciences des Materiaux, B.P. 95, Hammam-Lif 2050 (Tunisia); Elhouichet, H., E-mail: habib.elhouichet@fst.rnu.tn [Laboratoire des Materiaux Mineraux et leurs Applications, Centre National de Recherches en Sciences des Materiaux, B.P. 95, Hammam-Lif 2050 (Tunisia); Departement de Physique, Faculte des Sciences de Tunis, Universite de Tunis-ElManar ElManar 2092, Tunis (Tunisia); Gelloz, B. [Graduate School of Engineering, Tokyo University of Agriculture and Technology, 2-24-16 Nakacho, Koganei, 184-8588 Tokyo (Japan); Ferid, M. [Laboratoire des Materiaux Mineraux et leurs Applications, Centre National de Recherches en Sciences des Materiaux, B.P. 95, Hammam-Lif 2050 (Tunisia); Koshida, N. [Graduate School of Engineering, Tokyo University of Agriculture and Technology, 2-24-16 Nakacho, Koganei, 184-8588 Tokyo (Japan)

    2012-01-15

    In this work, structural, thermal and optical properties of Eu{sup 3+} doped TeO{sub 2}-La{sub 2}O{sub 3}-TiO{sub 2} glass were investigated. The differential scanning calorimetry (DSC) measurements reveal an important stability factor {Delta}T=143.52 K, which indicates the good thermal and mechanical stabilities of tellurite glass. From the absorption spectrum, the optical band gap was found to be direct with E{sub g}=3.23 eV. The temperature dependences of photoluminescence (PL) properties of Eu-doped and Eu-Tb codoped tellurite glass are investigated. As the temperature increases from 7 to 300 K, both the PL intensity and the PL lifetime relative to the {sup 5}D{sub 2}{yields}{sup 7}F{sub 0} are nearly constant below 230 K and then an enhancement takes place. This anomalous feature is attributed to the thermally activated carrier transfer process from charged intrinsic defects states to Eu{sup 3+} energy levels. By co-doping tellurite glasses with Eu and Tb, a strong Eu{sup 3+} PL enhancement is shown due to excitation transfer from Tb{sup 3+} and intrinsic defects to Eu ions. - Highlights: > TeO{sub 2}-La{sub 2}O{sub 3}-TiO{sub 2} glass doped Eu{sup 3+} with good thermal stability elaborated. > PL evolution of Eu{sup 3+} with temperature shows a non-conventional behavior. > Thermally activated carrier transfer from intrinsic defects states to Eu{sup 3+} shown. > Strong Eu{sup 3+} PL enhancement is shown in Eu-Tb codoped glass.

  2. Silicate glasses

    International Nuclear Information System (INIS)

    Lutze, W.

    1988-01-01

    Vitrification of liquid high-level radioactive wastes has received the greatest attention, world-wide, compared to any other HLW solidification process. The waste form is a borosilicate-based glass. The production of phosphate-based glass has been abandoned in the western world. Only in the Soviet Union are phosphate-based glasses still being developed. Vitrification techniques, equipment and processes and their remote operation have been developed and studied for almost thirty years and have reached a high degree of technical maturity. Industrial demonstration of the vitrification process has been in progress since 1978. This chapter is a survey of world-wide research and development efforts in nuclear waste glasses and its production technology. The principal glasses considered are silicate glasses which contain boron, i.e., borosilicate glasses

  3. Emission tunability and local environment in europium-doped OH{sup −}-free calcium aluminosilicate glasses for artificial lighting applications

    Energy Technology Data Exchange (ETDEWEB)

    Farias, Aline M.; Sandrini, Marcelo; Viana, José Renato M.; Baesso, Mauro L.; Bento, Antônio C.; Rohling, Jurandir H. [Departamento de Física, Universidade Estadual de Maringá, Av Colombo, 5790, 87020-900, Maringá, PR (Brazil); Guyot, Yannick [Laboratoire de Physico–Chimie des Matériaux Luminescents, Université de Lyon, Université Claude Bernard Lyon 1, Villeurbanne, UMR 5620 CNRS 69622 (France); De Ligny, Dominique [Department of Materials Science and Engineering, University of Erlangen Nürnberg, Martens str. 5, 91058, Erlangen (Germany); Nunes, Luiz Antônio O. [Instituto de Física de São Carlos, Universidade de São Paulo, Av. Trabalhador São-Carlense400, 13566-590, São Carlos, SP (Brazil); Gandra, Flávio G. [Instituto de Física Gleb Wataghin, Universidade Estadual de Campinas, 13083-859, Campinas, SP (Brazil); Sampaio, Juraci A. [Lab Ciências Físicas, Universidade Estadual Norte Fluminense, 28013-602, Campos Dos Goytacazes, RJ (Brazil); Lima, Sandro M.; Andrade, Luis Humberto C. [Grupo de Espectroscopia Óptica e Fototérmica, Universidade Estadual de Mato Grosso do Sul-UEMS, Dourados, MS, C. P. 351, CEP 79804-970 (Brazil); and others

    2015-04-15

    The relationship between emission tunability and the local environment of europium ions in OH{sup −}-free calcium aluminosilicate glasses was investigated, focusing on the development of devices for artificial lighting. Significant conversion of Eu{sup 3+} to Eu{sup 2+} was obtained by means of melting the glasses under a vacuum atmosphere and controlling the silica content, resulting in broad, intense, and tunable luminescence ranging from blue to red. Electron spin resonance and X-ray absorption near edge structure measurements enabled correlation of the luminescence behavior of the material with the Eu{sup 2+}/Eu{sup 3+} concentration ratio and changes in the surrounding ions' crystal field. The coordinates of the CIE 1931 chromaticity diagram were calculated from the spectra, and the contour maps showed that the light emitted from Eu{sup 2+} presented broad bands and enhanced color tuning, ranging from reddish-orange to blue. The results showed that these Eu doped glasses can be used for tunable white lighting by combining matrix composition and the adjustment of the pumping wavelength. - Highlights: • Eu{sup 2+}-doped OH{sup −} free calcium aluminosilicate glass as a new source for white lighting. • Correlation between emission tunability and local environment of europium ions. • Significant reduction of Eu{sup 3+} to Eu{sup 2+} by melting the glasses under vacuum atmosphere. • Broad, intense and tunable luminescence ranging from blue to red.

  4. Recycle Glass in Foam Glass Production

    DEFF Research Database (Denmark)

    Petersen, Rasmus Rosenlund; König, Jakob; Yue, Yuanzheng

    The foam glass industry turn recycle glass into heat insulating building materials. The foaming process is relative insensitive to impurities in the recycle glass. It is therefore considered to play an important role in future glass recycling. We show and discuss trends of use of recycled glasses...... in foam glass industry and the supply sources and capacity of recycle glass....

  5. Cosmos & Glass

    DEFF Research Database (Denmark)

    Beim, Anne

    1996-01-01

    The article unfolds the architectural visions of glass by Bruno Taut. It refers to inspirations by Paul Sheerbart and litterature and the Crystal Chain, also it analyses the tectonic univers that can be found in the glass pavillion for the Werkbund exposition in Cologne....

  6. Glass Glimpsed

    DEFF Research Database (Denmark)

    Lock, Charles

    2015-01-01

    Glass in poetry as it reflects the viewer and as its power of reflection are both reduced and enhanced by technology.......Glass in poetry as it reflects the viewer and as its power of reflection are both reduced and enhanced by technology....

  7. Spin glasses

    CERN Document Server

    Bovier, Anton

    2007-01-01

    Spin glass theory is going through a stunning period of progress while finding exciting new applications in areas beyond theoretical physics, in particular in combinatorics and computer science. This collection of state-of-the-art review papers written by leading experts in the field covers the topic from a wide variety of angles. The topics covered are mean field spin glasses, including a pedagogical account of Talagrand's proof of the Parisi solution, short range spin glasses, emphasizing the open problem of the relevance of the mean-field theory for lattice models, and the dynamics of spin glasses, in particular the problem of ageing in mean field models. The book will serve as a concise introduction to the state of the art of spin glass theory, usefull to both graduate students and young researchers, as well as to anyone curious to know what is going on in this exciting area of mathematical physics.

  8. GLASS BOX

    National Research Council Canada - National Science Library

    Curtis, Laura

    2008-01-01

    The goals of this effort were to develop Glass Box capabilities to allow for the capturing of analyst activities and the associated data resources, track and log the results of automated processing...

  9. Glass compositions

    Energy Technology Data Exchange (ETDEWEB)

    France, P W

    1985-05-30

    A fluoride glass for use in the production of optical fibres has an enhanced D/H ratio, preferably such that OD:OH is at least 9:1. In the example, such a glass is prepared by treating with D/sub 2/O a melt comprising 51.53 mole per cent ZrF/sub 4/, 20.47 mole per cent BaF/sub 2/, 5.27 mole per cent LaF/sub 3/, 3.24 mole per cent AlF/sub 3/, and 19.49 mole per cent LiF.

  10. Glass: Rotary Electric Glass Furnace

    Energy Technology Data Exchange (ETDEWEB)

    Recca, L.

    1999-01-29

    Compared to conventional gas-fired furnaces, the new rotary electric furnace will increase energy efficiency while significantly reducing air emissions, product turnaround time, and labor costs. As this informative new fact sheet explains, the thousand different types of glass optical blanks produced for the photonics industry are used for lasers, telescopes, cameras, lights, and many other products.

  11. Nitrate glass

    International Nuclear Information System (INIS)

    Kirilenko, I.A.; Vinogradov, E.E.

    1977-01-01

    Experimental evidence on behaviour of nitrate glasses is reviewed in terms of relationships between the presence of water in vitrescent nitrate systems and the properties of the systems. The glasses considered belong to systems of Mg(NO 3 ) 2 - Nd(NO 3 ) 3 ; Hg(NO 3 ) 2 -Nd(NO 3 ) 3 ; NaNO 3 -Mg(NO 3 ) 2 -Nd(NO 3 ) 3 ; M-Zn(NO 3 ) 3 , where M is a mixture of 20% mass NaNO 3 and 80% mass Mg(NO 3 ) 2 , and Zn is a rare earth ion. Nitrate glass is shown to be a product of dehydration. Vitrification may be regarded as a resusl of formation of molecular complexes in the chain due to hydrogen bonds of two types, i.e. water-water, or water-nicrate group. Chain formation, along with low melting points of the nitrates, hinder crystallization of nitrate melts. Provided there is enough water, this results in vitrification

  12. Photoluminescence studies on Eu doped TiO2 nanoparticles

    International Nuclear Information System (INIS)

    Ningthoujam, R.S.; Sudarsan, V.; Vatsa, R.K.; Kadam, R.M.; Jagannath; Gupta, A.

    2009-01-01

    Eu 3+ doped TiO 2 nanoparticles were prepared by urea hydrolysis in ethylene glycol medium at low temperature of 150 deg. C. X-ray diffraction study showed that anatase phase of tetragonal structure was formed below 500 deg. C; and above this temperature, additional peaks due to rutile phase were also observed. From luminescence study, it was found that as prepared nanoparticles showed the enhanced luminescence intensity due to energy transfer from host to europium ions. However, photoluminescence from these nanoparticles was found to disappear when the samples were heated above 900 deg. C. We established the origin of the reduction in the luminescence intensity from Eu 3+ when doped in TiO 2 and heated at 900 deg. C. Based on detailed studies at different heat-treatment temperatures using techniques such as X-ray diffraction, X-ray photoelectron spectroscopy, electron paramagnetic resonance, Raman spectroscopy, and Moessbauer spectroscopy, it has been established that formation of Eu 2 Ti 2 O 7 phase, wherein Eu 3+ ions occupy high symmetric environment (D 3d ) and also reduced distance between Eu 3+ and Eu 3+ ions is responsible for the decrease/loss in the luminescence intensity.

  13. Characterization and luminescence studies of Eu doped Barite nanophosphor

    Energy Technology Data Exchange (ETDEWEB)

    Bahl, Shaila, E-mail: shaila.bahl@gmail.com [Medical Physics Unit, IRCH, AIIMS, New Delhi 110029 (India); Lochab, S.P. [Inter-University Accelerator Center, Aruna Asaf Ali Marg, New Delhi 110067 (India); Pandey, Anant [Department of Physics, Sri Venkateswara College, University of Delhi, New Delhi 110021 (India); Kumar, Vipin [Department of Physics and Astrophysics, University of Delhi, New Delhi 110007 (India); Aleynikov, V.E.; Molokanov, A.G. [Joint Institute for Nuclear Research, Dubna 141980 (Russian Federation); Kumar, Pratik [Medical Physics Unit, IRCH, AIIMS, New Delhi 110029 (India)

    2014-05-01

    Barite (BaSO{sub 4}) nanophosphors were successfully prepared by the co-precipitation method. The structural analysis of the sample was carried out by analytical techniques such as X-ray diffraction (XRD), Transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FTIR) and Raman spectroscopy. XRD study reveals that the particles exhibit orthorhombic structure and are approximately 50 nm in size, while TEM study further confirms the particle size in the range 48–52 nm and depicts oval shape of the particles. The FTIR spectrum displays the bands centered at 1197 to1077 cm{sup −1} and the shoulder at 982 cm{sup −1} corresponding to the symmetrical vibration of SO{sub 4}{sup 2−} ion. Moreover, S–O bending and stretching are the Raman signature of barite, which were proven by the Raman spectra, unveiling the various vibrational modes of the compound. Samples were irradiated by gamma rays and proton beams and their Thermoluminescent (TL) glow curves were plotted and studied. On applying two different types of irradiations in addition to large energy difference, the sample showed almost a similar TL glow curve structure, which is the remarkable feature of this phosphor. Analysis of the glow curve was also carried out by the glow curve deconvolution method. Photoluminescence (PL) study shows broad excitation spectra with the main peak at around 250 nm whereas the emission band excited by the wavelength 250 nm was observed at 374 nm which corresponds to the 4f{sup 6}5d→4f{sup 7} ({sup 8}S{sub 7/2}) transitions of Eu{sup 2+} ions. The sample was also examined for its PL response to different exposures of gamma irradiations where it showed an increase in the PL intensity up to a dose of 800 Gy for both excitation and emission spectra. The present sample shows good crystal quality along with high TL and PL sensitivity. Hence our results suggest possible potential applications of nanocrystalline BaSO{sub 4}:Eu phosphor in dosimetric study of gamma and proton beams. - Highlights: • Dosimetric study of Barite nanophosphor doped with Europium for gamma and proton is investigated. • Sample shows a similar glow curve structure for both the irradiations, being different in energy as well as type (electromagnetic versus particulate). • The phosphor shows good TL linearity over a wide range for both the beams. • The detector can be used as a good dosimeter for measuring doses for gamma rays and proton beams. • Increased Photoluminescence intensity on irradiation can be exploited in area of scintillating devices.

  14. Luminescence performance of Eu -doped lead-free zinc phosphate ...

    Indian Academy of Sciences (India)

    luminescence properties in combination with its non-toxicity and non-hygroscopic nature ..... two colours will appear to the human eye as one colour and. Figure 10. ... [4] Mariappam C R, Govindaraj G, Rathan S V and Vijaya. Prakash G 2005 ...

  15. CRYSTALLIZATION IN MULTICOMPONENT GLASSES

    Energy Technology Data Exchange (ETDEWEB)

    KRUGER AA; HRMA PR

    2009-10-08

    In glass processing situations involving glass crystallization, various crystalline forms nucleate, grow, and dissolve, typically in a nonuniform temperature field of molten glass subjected to convection. Nuclear waste glasses are remarkable examples of multicomponent vitrified mixtures involving partial crystallization. In the glass melter, crystals form and dissolve during batch-to-glass conversion, melter processing, and product cooling. Crystals often agglomerate and sink, and they may settle at the melter bottom. Within the body of cooling glass, multiple phases crystallize in a non-uniform time-dependent temperature field. Self-organizing periodic distribution (the Liesegnang effect) is common. Various crystallization phenomena that occur in glass making are reviewed.

  16. Crystallization In Multicomponent Glasses

    International Nuclear Information System (INIS)

    Kruger, A.A.; Hrma, P.R.

    2009-01-01

    In glass processing situations involving glass crystallization, various crystalline forms nucleate, grow, and dissolve, typically in a nonuniform temperature field of molten glass subjected to convection. Nuclear waste glasses are remarkable examples of multicomponent vitrified mixtures involving partial crystallization. In the glass melter, crystals form and dissolve during batch-to-glass conversion, melter processing, and product cooling. Crystals often agglomerate and sink, and they may settle at the melter bottom. Within the body of cooling glass, multiple phases crystallize in a non-uniform time-dependent temperature field. Self-organizing periodic distribution (the Liesegnang effect) is common. Various crystallization phenomena that occur in glass making are reviewed.

  17. Recycling of Glass

    DEFF Research Database (Denmark)

    Christensen, Thomas Højlund; Damgaard, Anders

    2011-01-01

    Glass is used for many purposes, but in the waste system glass is predominantly found in terms of beverage and food containers with a relatively short lifetime before ending up in the waste. Furthermore there is a large amount of flat glass used in building materials which also ends up in the waste...... system; this glass though has a long lifetime before ending up in the waste. Altogether these product types add up to 82% of the production of the European glass industry (IPCC, 2001). Recycling of glass in terms of cleaning and refilling of bottles as well as the use of broken glass in the production...... of new glass containers is well established in the glass industry. This chapter describes briefly howglass is produced and howwaste glass is recycled in the industry. Quality requirements and use of recycled products are discussed, as are the resource and environmental issues of glass recycling....

  18. Spin glasses

    International Nuclear Information System (INIS)

    Mookerjee, Abhijit

    1976-01-01

    ''Spin glasses'', are entire class of magnetic alloys of moderate dilution, in which the magnetic atoms are far enough apart to be unlike the pure metal, but close enough so that the indirect exchange energy between them (mediated by the s-d interaction between local moments and conduction electrons) dominates all other energies. Characteristic critical phenomena displayed such as freezing of spin orientation at 'Tsub(c)' and spreading of magnetic ordering, are pointed out. Anomalous behaviour, associated with these critical phenomena, as reflected in : (i) Moessbauer spectroscopy giving hyperfine splitting at Tsub(c), (ii) maxima in susceptibility and remanent magnetism, (iii) thermopower maxima and change in slope, (iv) Characteristic cusp in susceptibility and its removal by very small magnetic fields, and (v) conductivity-resistivity measurements, are discussed. Theoretical developments aimed at explaining these phenomena, in particular, the ideas from percolation and localisation theories, and the approach based on the gellations of polymers, are discussed. Finally, a new approach based on renormalisation group in disordered systems is also briefly mentioned. (K.B.)

  19. lead glass brick

    CERN Multimedia

    When you look through the glass at a picture behind, the picture appears raised up because light is slowed down in the dense glass. It is this density (4.06 gcm-3) that makes lead glass attractive to physicists. The refractive index of the glass is 1.708 at 400nm (violet light), meaning that light travels in the glass at about 58% its normal speed. At CERN, the OPAL detector uses some 12000 blocks of glass like this to measure particle energies.

  20. Glass and nuclear wastes

    International Nuclear Information System (INIS)

    Sombret, C.

    1982-10-01

    Glass shows interesting technical and economical properties for long term storage of solidified radioactive wastes by vitrification or embedding. Glass composition, vitrification processes, stability under irradiation, thermal stability and aqueous corrosion are studied [fr

  1. Microstructuring of glasses

    CERN Document Server

    Hülsenberg, Dagmar; Bismarck, Alexander

    2008-01-01

    As microstructured glass becomes increasingly important for microsystems technology, the main application fields include micro-fluidic systems, micro-analysis systems, sensors, micro-actuators and implants. And, because glass has quite distinct properties from silicon, PMMA and metals, applications exist where only glass devices meet the requirements. The main advantages of glass derive from its amorphous nature, the precondition for its - theoretically - direction-independent geometric structurability. Microstructuring of Glasses deals with the amorphous state, various glass compositions and their properties, the interactions between glasses and the electromagnetic waves used to modify it. Also treated in detail are methods for influencing the geometrical microstructure of glasses by mechanical, chemical, thermal, optical, and electrical treatment, and the methods and equipment required to produce actual microdevices.

  2. Measurement of optical glasses

    International Nuclear Information System (INIS)

    Nicolau-Rebigan, S.

    1978-11-01

    The possibilities of measurement of the optical glasses parameters needed in building optical devices especially in lasers devices are presented. In the first chapter the general features of the main optical glasses as well as the modalities of obtaining them are given. Chapter two defines the optical glass parameters, and the third chapter describes the measuring methods of the optical glass parameters. Finally, the conclusions which point out the utilization of this paper are presented. (author)

  3. Mechanically reinforced glass beams

    DEFF Research Database (Denmark)

    Nielsen, Jens Henrik; Olesen, John Forbes

    2007-01-01

    laminated float glass beam is constructed and tested in four-point bending. The beam consist of 4 layers of glass laminated together with a slack steel band glued onto the bottom face of the beam. The glass parts of the tested beams are \\SI{1700}{mm} long and \\SI{100}{mm} high, and the total width of one...

  4. Fluoride glass fiber optics

    CERN Document Server

    Aggarwal, Ishwar D

    1991-01-01

    Fluoride Glass Fiber Optics reviews the fundamental aspects of fluoride glasses. This book is divided into nine chapters. Chapter 1 discusses the wide range of fluoride glasses with an emphasis on fluorozirconate-based compositions. The structure of simple fluoride systems, such as BaF2 binary glass is elaborated in Chapter 2. The third chapter covers the intrinsic transparency of fluoride glasses from the UV to the IR, with particular emphasis on the multiphonon edge and electronic edge. The next three chapters are devoted to ultra-low loss optical fibers, reviewing methods for purifying and

  5. Multiple Glass Ceilings

    OpenAIRE

    Russo, Giovanni; Hassink, Wolter

    2011-01-01

    Both vertical (between job levels) and horizontal (within job levels) mobility can be sources of wage growth. We find that the glass ceiling operates at both margins. The unexplained part of the wage gap grows across job levels (glass ceiling at the vertical margin) and across the deciles of the intra-job-level wage distribution (glass ceiling at the horizontal margin). This implies that women face many glass ceilings, one for each job level above the second, and that the glass ceiling is a p...

  6. Homogeneity of Inorganic Glasses

    DEFF Research Database (Denmark)

    Jensen, Martin; Zhang, L.; Keding, Ralf

    2011-01-01

    Homogeneity of glasses is a key factor determining their physical and chemical properties and overall quality. However, quantification of the homogeneity of a variety of glasses is still a challenge for glass scientists and technologists. Here, we show a simple approach by which the homogeneity...... of different glass products can be quantified and ranked. This approach is based on determination of both the optical intensity and dimension of the striations in glasses. These two characteristic values areobtained using the image processing method established recently. The logarithmic ratio between...

  7. Leaching of glass

    International Nuclear Information System (INIS)

    Hench, L.L.

    1977-01-01

    Understanding surface compositional profiles of glasses over a range of 0-2000 A with a variety of analytical instruments shows that five general types of glass surfaces exist. The surface character of a glass article depends upon bulk composition and environmental history during which surface dealkalization, film formation, and network dissolution can occur. Environmental-surface interactions generally result in complex compositional profiles of all the constituents in a glass. Durable glasses almost always develop a stable surface film which has a higher concentration of network formers than the bulk composition. Compositional effects that are used to improve glass durability usually improve the stability of the surface films. Durability tests or service conditions that lead to film destruction are especially severe for the most silicate glasses. 43 references

  8. Fractography of glass

    CERN Document Server

    Tressler, Richard

    1994-01-01

    As the first major reference on glass fractography, contributors to this volume offer a comprehensive account of the fracture of glass as well as various fracture surface topography Contributors discuss optical fibers, glass containers, and flatglass fractography In addition, papers explore fracture origins; the growth of the original flaws of defects; and macroscopic fracture patterns from which fracture patterns evolve This volume is complete with photographs and schematics

  9. Diamond turning of glass

    Energy Technology Data Exchange (ETDEWEB)

    Blackley, W.S.; Scattergood, R.O.

    1988-12-01

    A new research initiative will be undertaken to investigate the critical cutting depth concepts for single point diamond turning of brittle, amorphous materials. Inorganic glasses and a brittle, thermoset polymer (organic glass) are the principal candidate materials. Interrupted cutting tests similar to those done in earlier research are Ge and Si crystals will be made to obtain critical depth values as a function of machining parameters. The results will provide systematic data with which to assess machining performance on glasses and amorphous materials

  10. Glass to contain wastes

    International Nuclear Information System (INIS)

    Moncouyoux, M.; Jacquet-Francillon, M.

    1994-01-01

    Here are the tables and figures presented during the conference on the glass to confine high level radioactive wastes: definition, fabrication, storage and disposal. The composition of glasses are detailed, their properties and the vitrification proceeding. The behaviour of these glasses in front of water, irradiation and heat are shown. The characteristics of parcels are given according to the radiation protection rule, ALARA principle, the concept of multi-barriers and the geological stability

  11. Glass microspheres for brachytherapy

    International Nuclear Information System (INIS)

    Prado, Miguel O.; Prastalo, Simon; Blaumann, Herman; Longhino, Juan M.; Repetto Llamazares, A.H.V.

    2007-01-01

    We developed the capacity to produce glass microspheres containing in their structure one or more radioactive isotopes useful for brachytherapy. We studied the various facts related with their production: (Rare earth) alumino silicate glass making, glass characterization, microspheres production, nuclear activation through (n,γ) nuclear reactions, mechanical characterization before and after irradiation. Corrosion tests in simulated human plasma and mechanical properties characterization were done before and after irradiation. (author) [es

  12. Silicate glasses. Chapter 1

    International Nuclear Information System (INIS)

    Lutze, W.

    1988-01-01

    This chapter is a survey of world-wide research and development efforts in nuclear waste glasses and its production technology. The principal glasses considered are silicate glasses which contain boron, i.e. borosilicate glass. A historical overview of waste form development programs in nine countries is followed by a summary of the design criteria for borosilicate glass compositions glass compositions. In the sections on glass properties the waste form is characterized in terms of potential alterations under the influence of heat, thermal gradients, radiation, aqueous solutions and combinations thereof. The topics are phase transformations, mechanical properties, radiation effects and chemical durability. The results from studies of volcanic glasses, as natural analogues for borosilicate nuclear waste glasses in order to verify predictions obtained from short-term tests in the laboratory, have been compiled in a special section on natural analogues. A special section on advanced vitrification techniques summarizes the various actual and potential processing schemes and describes the facilities. The literature has been considered until 1985. (author). 430 refs.; 68 figs.; 29 tabs

  13. Glass and vitrification

    International Nuclear Information System (INIS)

    Barton, J.L.; Vacher, R.; Moncouyoux, J.P.; Vernaz, E.

    1997-01-01

    Most glasses used as materials are oxides glasses that are produced by a quick quench of a liquid. Glasses are characterized by the absence of periodicity in the atomic arrangements, they do not have symmetries and do not present order over a long distance. This series of 4 short articles present: 1) the properties of glass and its industrial story, 2) the glass structure, 3) a forty years long story of glass as dies used to confine wastes and 4) the methodology used to study the behaviour of glass over very long periods of time. This methodology is based on 5 steps: 1) define and specify the material to study (the prediction of long term alteration of a material is nonsense unless you know well its initial properties), 2) identify all the alteration processes that are likely to happen, determine their kinetics and the influence of environmental parameters, 3) develop mathematical models in order to simulate long-term behaviour of glasses, 4) determine the release rates of the radionuclides confined in the glass, and 5) validate data and models, it is not possible to expect a complete validation of a model that will be extrapolated over tens of thousands of years, nevertheless some ways of validation can lead to a satisfactory level of confidence taking into account reasonable uncertainties. (A.C.)

  14. Characterization of glass and glass ceramic nuclear waste forms

    International Nuclear Information System (INIS)

    Lutze, W.; Borchardt, J.; De, A.K.

    1979-01-01

    Characteristics of solidified nuclear waste forms, glass and glass ceramic compositions and the properties (composition, thermal stability, crystallization, phase behavior, chemical stability, mechanical stability, and radiation effects) of glasses and glass ceramics are discussed. The preparation of glass ceramics may be an optional step for proposed vitrification plants if tailored glasses are used. Glass ceramics exhibit some improved properties with respect to glasses. The overall leach resistance is similar to that of glasses. An increased leach resistance may become effective for single radionuclides being hosted in highly insoluble crystal phases mainly when higher melting temperatures are applicable in order to get more leach resistant residual glass phases. The development of glass ceramic is going on. The technological feasibility is still to be demonstrated. The potential gain of stability when using glass ceramics qualifies the material as an alternative nuclear waste form

  15. Relaxations in spin glasses: Similarities and differences from ordinary glasses

    International Nuclear Information System (INIS)

    Ngai, K.L.; Rajagopal, A.K.; Huang, C.Y.

    1984-01-01

    Relaxation phenomena have become a major concern in the physics of spin glasses. There are certain resemblances of these relaxation properties to those of ordinary glasses. In this work, we compare the relaxation properties of spin glasses near the freezing temperature with those of glasses near the glass transition temperature. There are similarities between the two types of glasses. Moreover, the relaxation properties of many glasses and spin glasses are in conformity with two coupled ''universality'' relations predicted by a recent model of relaxations in condensed matter

  16. Evaluation of Structural Cellular Glass

    Science.gov (United States)

    Adams, M. A.; Zwissler, J. G.

    1984-01-01

    Preliminary design information presented. First report discusses state of structural-cellular-glass programs as of June 1979. Second report gives further details of program to develop improved cellular glasses and to characterize properties of glasses and commercially available materials.

  17. Electric glass capturing markets

    Energy Technology Data Exchange (ETDEWEB)

    Wikman, K.; Wikstroem, T.

    1996-11-01

    Electric glass has found its place on the construction market. In public buildings, electrically heatable windows are becoming the leading option for large glass walls. Studies on detached houses, both new and renovated, show that floor heating combined with electrically heatable windowpanes is the best choice with respect to resident`s comfort. (orig.)

  18. Radioresistance of inorganic glasses

    International Nuclear Information System (INIS)

    Vorob'ev, A.A.; Zavadovskaya, E.K.; Fedorov, B.V.; Starodubtsev, V.A.

    1977-01-01

    Regularities are considered in the variation of properties of glass due to irradiations. On the basis of previous theoretical statements and experimental investigations, it is inferred that the irradiation resistance of glasses of the same type, synthesis conditions, content of impurities and amount of imperfections, is a function of the ''element-oxygen'' bond energy. The irradiation resistance depends on the number and the nature of glass structure imperfections. The averaged level of bonding forces is indicative of the glass formation temperature; the imperfections in glasses are formed in structure elements whose amount predominates as compared to the others. Electric charges which accumulate on the crack surface tend to increase its size, thus lessening even further the electric strength of the dielectric. The greater the irradiation time, the greater the number of irradiation imperfections causing a drop in the electric strength of glass. When choosing a glass for service in a radiation field, it is necessary to select those of a highest temperature of glass formation and with a least amount of imperfections

  19. Nucleation in ZBLAN glasses

    NARCIS (Netherlands)

    de Leede, G.L.A.; Waal, de H.

    1989-01-01

    Nucleation rates were detd. in a ZrF4-BaF2-NaF-LaF3-AlF3 glass (ZBLAN) using an optical method. The results were compared with a similar glass having a slightly different compn. The difference in the nucleation rate is explained by classical nucleation theory using calcd. free-energy differences

  20. Mechanical relaxation in glasses

    International Nuclear Information System (INIS)

    Hiki, Y.

    2004-01-01

    The basic properties of glasses and the characteristics of mechanical relaxation in glasses were briefly reviewed, and then our studies concerned were presented. Experimental methods adopted were viscosity, internal friction, ultrasonic attenuation, and Brillouin scattering measurements. The specimens used were several kinds of inorganic, organic, and metallic glasses. The measurements were mainly carried out from the room temperature up to the glass transition temperature, and the relaxation time was determined as a function of temperature. The 'double relaxation' composed of two Arrhenius-type relaxations was observed in many materials. In both relaxations, the 'compensation effect' showing a correlation of the pre-exponential factor and the activation energy was observed. These results were explained by considering the 'complex relaxation' due to cooperative motions of atoms or group of atoms. Values of activation energy near the glass transition determined by the various experimental methods were compared with each other

  1. Polymorphism in glasses

    International Nuclear Information System (INIS)

    Landa, L.M.; Nikolaeva, I.N.

    1979-01-01

    To defect phase interfaces and spasmodic properties change, the inhomogeneity and the second radiation effects in quartz glass, metamict phase and intermediate states have been investigated. When irradiating with fast neutrons the transformation of quartz glass - metamict phase occurs completely. The transformation is completed at 2x10 20 part./cm 2 dose. Thermal treatment not only increases the number of inhomogeneities but also results in increasing quartz glass density. Annealing transforms the metamict phase into common quartz glass at 1400 K. The fact, that thermal treatment results in the complete transformation of metamict phase into quartz glass, and the inverse transformation occurs only partially, is quite regular, as the metamict phase has a lesser entropy and is a more ordered state. It is shown that different amorphous phases of a chemical composition have different structures and properties, that there are interfaces between them, and the transformation from one state to another in microvolumes is realized spasmodically and requires expenditure of energy

  2. Glass leaching performance

    International Nuclear Information System (INIS)

    Chick, L.A.; Turcotte, R.P.

    1983-05-01

    Current understanding of the leaching performance of high-level nuclear waste (HLW) glass is summarized. The empirical model of waste glass leaching behavior developed shows that at high water flow rates the glass leach rate is kinetically limited to a maximum value. At intermediate water flow rates, leaching is limited by the solution concentration of silica and decreases with decreasing water flow rates. Release of soluble elements is controlled by silica dissolution because silica forms the binding network of the glass. At low water flow rates, mass loss rates reach values controlled by formation rates of alteration minerals, or by diffusion of dissolution products through essentially stagnant water. The parameters reviewed with respect to their quantifiable influence on leaching behavior include temperature, pH, leachant composition, glass composition, thermal history, and radiation. Of these, temperature is most important since the rate of mass loss approximately doubles with each 10 0 C increase in dilute solutions. The pH has small effects within the 4 to 10 range. The chemical composition of the leachant is most important with regard to its influence on alteration product formation. Glass composition exhibits the largest effects at high flow rates where improved glasses leach from ten to thirty times slower than glass 76 to 68. The effects of the thermal history (devitrification) of the glass are not likely to be significant. Radiation effects are important primarily in that radiolysis can potentially drive pH values to less than 4. Radiation damage to the glass causes insignificant changes in leaching performance

  3. Thermal Conductivity of Foam Glass

    DEFF Research Database (Denmark)

    Petersen, Rasmus Rosenlund; König, Jakob; Yue, Yuanzheng

    Due to the increased focus on energy savings and waste recycling foam glass materials have gained increased attention. The production process of foam glass is a potential low-cost recycle option for challenging waste, e.g. CRT glass and industrial waste (fly ash and slags). Foam glass is used...... as thermal insulating material in building and chemical industry. The large volume of gas (porosity 90 – 95%) is the main reason of the low thermal conductivity of the foam glass. If gases with lower thermal conductivity compared to air are entrapped in the glass melt, the derived foam glass will contain...... only closed pores and its overall thermal conductivity will be much lower than that of the foam glass with open pores. In this work we have prepared foam glass using different types of recycled glasses and different kinds of foaming agents. This enabled the formation of foam glasses having gas cells...

  4. Effect of different glasses in glass bonded zeolite

    International Nuclear Information System (INIS)

    Lewis, M.A.; Ackerman, J.P.; Verma, S.

    1995-01-01

    A mineral waste form has been developed for chloride waste salt generated during the pyrochemical treatment of spent nuclear fuel. The waste form consists of salt-occluded zeolite powders bound within a glass matrix. The zeolite contains the salt and immobilizes the fission products. The zeolite powders are hot pressed to form a mechanically stable, durable glass bonded zeolite. Further development of glass bonded zeolite as a waste form requires an understanding of the interaction between the glass and the zeolite. Properties of the glass that enhance binding and durability of the glass bonded zeolite need to be identified. Three types of glass, boroaluminosilicate, soda-lime silicate, and high silica glasses, have a range of properties and are now being investigated. Each glass was hot pressed by itself and with an equal amount of zeolite. MCC-1 leach tests were run on both. Soda-lime silicate and high silica glasses did not give a durable glass bonded zeolite. Boroaluminosilicate glasses rich in alkaline earths did bind the zeolite and gave a durable glass bonded zeolite. Scanning electron micrographs suggest that the boroaluminosilicate glasses wetted the zeolite powders better than the other glasses. Development of the glass bonded zeolite as a waste form for chloride waste salt is continuing

  5. Oxynitride glasses: a review

    Energy Technology Data Exchange (ETDEWEB)

    Garcia, A.R.; Clausell, C.; Barba, A.

    2016-07-01

    Oxynitride glasses are special types of silicates or silicoaluminates which have been the object of many studies over the last forty years. They can be prepared by means of various complex methods, leading to variable levels of nitrogen incorporation, though in all cases giving limited transparency in the visible range. More recently, a new family of oxynitride glasses incorporating fluorine has been investigated. This paper outlines the effect of composition, in particular nitrogen and fluorine content, on properties such as glass transition temperature, hardness, Young's modulus, compactness and molar volume. (Author)

  6. Orbital glass in HTSC

    International Nuclear Information System (INIS)

    Kusmartsev, F.V.

    1992-10-01

    The physical reasons why the orbital glass may exist in granular high-temperature superconductors and the existing experimental data appeared recently are discussed. The orbital glass is characterized by the coexistence of the orbital paramagnetic state with the superconducting state and occurs at small magnetic fields H c0 c1 . The transition in orbital glass arises at the critical field H c0 which is inversely proportional to the surface cross-area S of an average grain. In connection with theoretical predictions the possible experiments are proposed. (author). 10 refs

  7. Bioactive glasses and glass-ceramics

    Directory of Open Access Journals (Sweden)

    de Aza, P. N.

    2007-04-01

    Full Text Available Since the late 1960´s, a great interest in the use of bioceramic materials for biomedical applications has been developed. In a previous paper, the authors reviewed crystalline bioceramic materials “sensus stricto”, it is to say, those ceramic materials, constituted for non-metallic inorganic compounds, crystallines and consolidates by thermal treatment of powders at high temperature. In the present review, the authors deal with those called bioactive glasses and glassceramics. Although all of them are also obtained by thermal treatment at high temperature, the first are amorphous and the second are obtained by devitrification of a glass, although the vitreous phase normally prevails on the crystalline phases. After an introduction to the concept of bioactive materials, a short historical review of the bioactive glasses development is made. Its preparation, reactivity in physiological media, mechanism of bonding to living tissues and mechanical strength of the bone-implant interface is also reported. Next, the concept of glass-ceramic and the way of its preparation are exposed. The composition, physicochemical properties and biological behaviour of the principal types of bioactive glasses and glass-ceramic materials: Bioglass®, Ceravital®, Cerabone®, Ilmaplant® and Bioverit® are also reviewed. Finally, a short review on the bioactive-glass coatings and bioactive-composites and most common uses of bioactive-glasses and glass-ceramics are carried out too.

    Desde finales de los años sesenta, se ha despertado un gran interés por el uso de los materiales biocerámicos para aplicaciones biomédicas. En un trabajo previo, los autores hicieron una revisión de los denominados materiales biocerámicos cristalinos en sentido estricto, es decir, de aquellos materiales, constituidos por compuestos inorgánicos no metálicos, cristalinos y consolidados mediante tratamientos térmicos a altas temperaturas. En el presente trabajo, los autores

  8. Fun with Singing Wine Glasses

    Science.gov (United States)

    Boone, Christine; Galloway, Melodie; Ruiz, Michael J.

    2018-01-01

    A fun activity is presented using singing wine glasses for introductory physics students. Students tune a white wine glass and a red wine glass to as many semitones as possible by filling the glasses with the appropriate amounts of water. A smart phone app is used to measure the frequencies of equal-temperament tones. Then plots of frequency…

  9. Waste glass weathering

    International Nuclear Information System (INIS)

    Bates, J.K.; Buck, E.C.

    1994-01-01

    The weathering of glass is reviewed by examining processes that affect the reaction of commercial, historical, natural, and nuclear waste glass under conditions of contact with humid air and slowly dripping water, which may lead to immersion in nearly static solution. Radionuclide release data from weathered glass under conditions that may exist in an unsaturated environment are presented and compared to release under standard leaching conditions. While the comparison between the release under weathering and leaching conditions is not exact, due to variability of reaction in humid air, evidence is presented of radionuclide release under a variety of conditions. These results suggest that both the amount and form of radionuclide release can be affected by the weathering of glass

  10. Super ionic conductive glass

    Science.gov (United States)

    Susman, S.; Volin, K.J.

    Described is an ionically conducting glass for use as a solid electrolyte in a power or secondary cell containing an alkali metal-containing anode and a cathode separated by an alkali metal ion conducting glass having an ionic transference number of unity and the general formula: A/sub 1 + x/D/sub 2-x/3/Si/sub x/P/sub 3 - x/O/sub 12 - 2x/3/, wherein A is a network modifier for the glass and is an alkali metal of the anode, D is an intermediate for the glass and is selected from the class consisting of Zr, Ti, Ge, Al, Sb, Be, and Zn and X is in the range of from 2.25 to 3.0. Of the alkali metals, Na and Li are preferred and of the intermediate, Zr, Ti and Ge are preferred.

  11. Phosphate glasses, containing nitrogen

    International Nuclear Information System (INIS)

    Lisitsyna, E.A.; Khalilev, V.D.; Koryavin, A.A.; Goncharova, L.N.

    1987-01-01

    Possibilities of nitrogen-containing glass synthesis by the introduction into the charge of ammonium salts, as well as aluminium nitride, are studied. Zinc alumoyttrium phosphate glass (mol. %) Zn(PO 3 ) 2 - 4O, Al(PO 3 ) 3 - 3O, Y(PO 3 ) 3 -3O is suggested as a matrix. It is shown that the effect of amide and imide groups on the properties of the glass is less noticeable than the effect of nitride groups. Direct introduction of nitride constituent was realized using AlN, but aluminium introduction was taken into account so that the oxide was subtracted. The attempt to introduce more than 2.5 mass % of nitrogen into initial matrix by aluminium nitride has failed due to repeated restoration of glass with amorphous phosphorus isolation

  12. Baseline LAW Glass Formulation Testing

    International Nuclear Information System (INIS)

    Kruger, Albert A.; Mooers, Cavin; Bazemore, Gina; Pegg, Ian L.; Hight, Kenneth; Lai, Shan Tao; Buechele, Andrew; Rielley, Elizabeth; Gan, Hao; Muller, Isabelle S.; Cecil, Richard

    2013-01-01

    The major objective of the baseline glass formulation work was to develop and select glass formulations that are compliant with contractual and processing requirements for each of the LAW waste streams. Other objectives of the work included preparation and characterization of glasses with respect to the properties of interest, optimization of sulfate loading in the glasses, evaluation of ability to achieve waste loading limits, testing to demonstrate compatibility of glass melts with melter materials of construction, development of glass formulations to support ILAW qualification activities, and identification of glass formulation issues with respect to contract specifications and processing requirements

  13. Wastes based glasses and glass-ceramics

    Directory of Open Access Journals (Sweden)

    Barbieri, L.

    2001-12-01

    Full Text Available Actually, the inertization, recovery and valorisation of the wastes coming from municipal and industrial processes are the most important goals from the environmental and economical point of view. An alternative technology capable to overcome the problem of the dishomogeneity of the raw material chemical composition is the vitrification process that is able to increase the homogeneity and the constancy of the chemical composition of the system and to modulate the properties in order to address the reutilization of the waste. Moreover, the glasses obtained subjected to different controlled thermal treatments, can be transformed in semy-cristalline material (named glass-ceramics with improved properties with respect to the parent amorphous materials. In this review the tailoring, preparation and characterization of glasses and glass-ceramics obtained starting from municipal incinerator grate ash, coal and steel fly ashes and glass cullet are described.

    Realmente la inertización, recuperación y valorización de residuos que proceden de los procesos de incineración de residuos municipales y de residuos industriales son metas importantes desde el punto de vista ambiental y económico. Una tecnología alternativa capaz de superar el problema de la heterogeneidad de la composición química de los materiales de partida es el proceso de la vitrificación que es capaz de aumentar la homogeneidad y la constancia de la composición química del sistema y modular las propiedades a fin de la reutilización del residuo. En este artículo se presentan los resultados de vitrificación en que los vidrios fueron sometidos a tratamientos térmicos controlados diferentes, de manera que se transforman en materiales semicristalinos (también denominados vitrocerámicos con mejores propiedades respecto a los materiales amorfos originales. En esta revisión se muestra el diseño, preparación y caracterización de vidrios y vitrocerámicos partiendo de

  14. DWPF GLASS BEADS AND GLASS FRIT TRANSPORT DEMONSTRATION

    Energy Technology Data Exchange (ETDEWEB)

    Adamson, D; Bradley Pickenheim, B

    2008-11-24

    DWPF is considering replacing irregularly shaped glass frit with spherical glass beads in the Slurry Mix Evaporator (SME) process to decrease the yield stress of the melter feed (a non-Newtonian Bingham Plastic). Pilot-scale testing was conducted on spherical glass beads and glass frit to determine how well the glass beads would transfer when compared to the glass frit. Process Engineering Development designed and constructed the test apparatus to aid in the understanding and impacts that spherical glass beads may have on the existing DWPF Frit Transfer System. Testing was conducted to determine if the lines would plug with the glass beads and the glass frit slurry and what is required to unplug the lines. The flow loop consisted of vertical and horizontal runs of clear PVC piping, similar in geometry to the existing system. Two different batches of glass slurry were tested: a batch of 50 wt% spherical glass beads and a batch of 50 wt% glass frit in process water. No chemicals such as formic acid was used in slurry, only water and glass formers. The glass beads used for this testing were commercially available borosilicate glass of mesh size -100+200. The glass frit was Frit 418 obtained from DWPF and is nominally -45+200 mesh. The spherical glass beads did not have a negative impact on the frit transfer system. The transferring of the spherical glass beads was much easier than the glass frit. It was difficult to create a plug with glass bead slurry in the pilot transfer system. When a small plug occurred from setting overnight with the spherical glass beads, the plug was easy to displace using only the pump. In the case of creating a man made plug in a vertical line, by filling the line with spherical glass beads and allowing the slurry to settle for days, the plug was easy to remove by using flush water. The glass frit proved to be much more difficult to transfer when compared to the spherical glass beads. The glass frit impacted the transfer system to the point

  15. Optimized Synthesis of Foam Glass from Recycled CRT Panel Glass

    DEFF Research Database (Denmark)

    Petersen, Rasmus Rosenlund; König, Jakob; Yue, Yuanzheng

    Most of the panel glass from cathode ray tubes (CRTs) is landfilled today. Instead of landfilling, the panel glass can be turned into new environment-friendly foam glass. Low density foam glass is an effective heat insulating material and can be produced just by using recycle glass and foaming...... additives. In this work we recycle the CRT panel glass to synthesize the foam glass as a crucial component of building and insulating materials. The synthesis conditions such as foaming temperature, duration, glass particle size, type and concentrations of foaming agents, and so on are optimized...... by performing systematic experiments. In particular, the concentration of foaming agents is an important parameter that influences the size of bubbles and the distribution of bubbles throughout the sample. The foam glasses are characterised regarding density and open/closed porosity. Differential scanning...

  16. DWPF GLASS BEADS AND GLASS FRIT TRANSPORT DEMONSTRATION

    International Nuclear Information System (INIS)

    Adamson, D.; Pickenheim, Bradley

    2008-01-01

    DWPF is considering replacing irregularly shaped glass frit with spherical glass beads in the Slurry Mix Evaporator (SME) process to decrease the yield stress of the melter feed (a non-Newtonian Bingham Plastic). Pilot-scale testing was conducted on spherical glass beads and glass frit to determine how well the glass beads would transfer when compared to the glass frit. Process Engineering Development designed and constructed the test apparatus to aid in the understanding and impacts that spherical glass beads may have on the existing DWPF Frit Transfer System. Testing was conducted to determine if the lines would plug with the glass beads and the glass frit slurry and what is required to unplug the lines. The flow loop consisted of vertical and horizontal runs of clear PVC piping, similar in geometry to the existing system. Two different batches of glass slurry were tested: a batch of 50 wt% spherical glass beads and a batch of 50 wt% glass frit in process water. No chemicals such as formic acid was used in slurry, only water and glass formers. The glass beads used for this testing were commercially available borosilicate glass of mesh size -100+200. The glass frit was Frit 418 obtained from DWPF and is nominally -45+200 mesh. The spherical glass beads did not have a negative impact on the frit transfer system. The transferring of the spherical glass beads was much easier than the glass frit. It was difficult to create a plug with glass bead slurry in the pilot transfer system. When a small plug occurred from setting overnight with the spherical glass beads, the plug was easy to displace using only the pump. In the case of creating a man made plug in a vertical line, by filling the line with spherical glass beads and allowing the slurry to settle for days, the plug was easy to remove by using flush water. The glass frit proved to be much more difficult to transfer when compared to the spherical glass beads. The glass frit impacted the transfer system to the point

  17. Nuclear waste glass corrosion mechanisms

    International Nuclear Information System (INIS)

    Jantzen, C.M.

    1987-04-01

    Dissolution of nuclear waste glass occurs by corrosion mechanisms similar to those of other solids, e.g., metallurgical and mineralogic systems. Metallurgical phenomena such as active corrosion, passivation and immunity have been observed to be a function of the glass composition and the solution pH. Hydration thermodynamics was used to quantify the role of glass composition and its effect on the solution pH during dissolution. A wide compositional range of natural, lunar, medieval, and nuclear waste glasses, as well as some glass-ceramics were investigated. The factors observed to affect dissolution in deionized water are pertinent to the dissolution of glass in natural environments such as the groundwaters anticipated to interact with nuclear waste glass in a geologic repository. The effects of imposed pH and oxidation potential (Eh) conditions existing in natural environments on glass dissolution is described in the context of Pourbaix diagrams, pH potential diagrams, for glass

  18. Electrical properties of phosphate glasses

    International Nuclear Information System (INIS)

    Mogus-Milankovic, A; Santic, A; Reis, S T; Day, D E

    2009-01-01

    Investigation of the electrical properties of phosphate glasses where transition metal oxide such as iron oxide is the network former and network modifier is presented. Phosphate glasses containing iron are electronically conducting glasses where the polaronic conduction is due to the electron hopping from low to high iron valence state. The identification of structural defects caused by ion/polaron migration, the analysis of dipolar states and electrical conductivity in iron phosphate glasses containing various alkali and mixed alkali ions was performed on the basis of the impedance spectroscopy (IS). The changes in electrical conductivity from as-quenched phosphate glass to fully crystallized glass (glass-ceramics) by IS are analyzed. A change in the characteristic features of IS follows the changes in glass and crystallized glass network. Using IS, the contribution of glass matrix, crystallized grains and grain boundary to the total electrical conductivity for iron phosphate glasses was analyzed. It was shown that decrease in conductivity is caused by discontinuities in the conduction pathways as a result of the disruption of crystalline network where two or more crystalline phases are formed. Also, phosphate-based glasses offer a unique range of biomaterials, as they form direct chemical bonding with hard/soft tissue. The surface charges of bioactive glasses are recognized to be the most important factors in determining biological responses. The improved bioactivity of the bioactive glasses as a result of the effects of the surface charges generated by electrical polarization is discussed.

  19. Theory of glass

    International Nuclear Information System (INIS)

    Rivier, N.

    1985-01-01

    The physical properties of glass are direct consequences of its non-crystalline structure. The structure is described from a topological point of view, since topology is the only geometry surviving non-crystallinity, i.e. absence of metric and trivial space group. This fact has two main consequences: the overall homogeneity of glass is a gauge symmetry, and the only extended, structurally stable constituents are odd lines (or 2π-disclinations in the elastic continuum limit). A gauge theory of glass, based on odd lines as sources of frozen-in strain, can explain those properties of glasses which are both specific to, and universal in amorphous solids: low-temperature excitations, and relaxation at high temperatures. The methods of statistical mechanics can be applied to give a minimal description of amorphous structures in statistical equilibrium. Criteria for statistical equilibrium of the structure and detailed balance are given, together with structural equations of state, which turn out to be well-known empirically among botanists and metallurgists. This review is based on lectures given in 1984 in Niteroi. It contains five parts: I - Structure, from a topological viewpoint; II - gauge invariance; III - Tunneling modes; IV - Supercooled liquid and the glass transitions; V - Statistical crystallography. (Author) [pt

  20. Sol-Gel Glasses

    Science.gov (United States)

    Mukherjee, S. P.

    1985-01-01

    Multicomponent homogeneous, ultrapure noncrystalline gels/gel derived glasses are promising batch materials for the containerless glass melting experiments in microgravity. Hence, ultrapure, homogeneous gel precursors could be used to: (1) investigate the effect of the container induced nucleation on the glass forming ability of marginally glass forming compositions; and (2) investigate the influence of gravity on the phase separation and coarsening behavior of gel derived glasses in the liquid-liquid immiscibility zone of the nonsilicate systems having a high density phase. The structure and crystallization behavior of gels in the SiO2-GeO2 as a function of gel chemistry and thermal treatment were investigated. As are the chemical principles involved in the distribution of a second network former in silica gel matrix being investigated. The procedures for synthesizing noncrystalline gels/gel-monoliths in the SiO2-GeO2, GeO2-PbO systems were developed. Preliminary investigations on the levitation and thermal treatment of germania silicate gel-monoliths in the Pressure Facility Acoustic Levitator were done.

  1. Ion exchange for glass strengthening

    International Nuclear Information System (INIS)

    Gy, Rene

    2008-01-01

    This paper presents a short overview of silicate glass strengthening by exchange of alkali ions in a molten salt, below the glass transition temperature (chemical tempering). The physics of alkali inter-diffusion is briefly explained and the main parameters of the process, which control the glass reinforcement, are reviewed. Methods for characterizing the obtained residual stress state and the strengthening are described, along with the simplified modelling of the stress build-up. The fragmentation of chemically tempered glass is discussed. The concept of engineered stress profile glass is presented, and finally, the effect of glass and salt compositions is overviewed

  2. Perspectives on spin glasses

    CERN Document Server

    Contucci, Pierluigi

    2013-01-01

    Presenting and developing the theory of spin glasses as a prototype for complex systems, this book is a rigorous and up-to-date introduction to their properties. The book combines a mathematical description with a physical insight of spin glass models. Topics covered include the physical origins of those models and their treatment with replica theory; mathematical properties like correlation inequalities and their use in the thermodynamic limit theory; main exact solutions of the mean field models and their probabilistic structures; and the theory of the structural properties of the spin glass phase such as stochastic stability and the overlap identities. Finally, a detailed account is given of the recent numerical simulation results and properties, including overlap equivalence, ultrametricity and decay of correlations. The book is ideal for mathematical physicists and probabilists working in disordered systems.

  3. Waste glass melting stages

    International Nuclear Information System (INIS)

    Anderson, L.D.; Dennis, T.; Elliott, M.L.; Hrma, P.

    1994-01-01

    Three simulated nuclear waste glass feeds, consisting of dried waste and glass frit, were heat treated for 1 hour in a gradient furnace at temperatures ranging from approximately 600 degrees C to 1000 degrees C. Simulated melter feeds from the Hanford Waste Vitrification Plant (HWVP), the Defense Waste Processing Facility (DWPF), and Kernforschungszentru Karlsruhe (KfK) in Germany were used. The samples were thin sectioned and examined by optical microscopy to investigate the stages of the conversion from feed to glass. Various phenomena were seen, such as frit softening, bubble formation, foaming, bubble motion and removal, convective mixing, and homogenization. The behavior of different feeds was similar, although the degree of gas generation and melt homogenization varied. 2 refs., 8 tabs

  4. Waste glass melting stages

    International Nuclear Information System (INIS)

    Anderson, L.D.; Dennis, T.; Elliott, M.L.; Hrma, P.

    1993-04-01

    Three different simulated nuclear waste glass feeds, consisting of dried waste and glass frit, were heat treated for 1 hour in a gradient furnace at temperatures ranging from approximately 600 degrees C--1000 degrees C. Simulated melter feeds from the Hanford Waste Vitrification Plant (HWVP), the Defense Waste Processing Facility (DWPF), and Kernforschungszentrum Karlsruhe (KfK) in Germany were used. The samples were thin-sectioned and examined by optical microscopy to investigate the stages of the conversion from feed to glass. Various phenomena were seen, such as frit softening, bubble formation, foaming, bubble motion and removal, convective mixing, and homogenization. Behavior of different feeds was similar, although the degree of gas generation and melt homogenization varied

  5. Using physical properties of molten glass to estimate glass composition

    International Nuclear Information System (INIS)

    Choi, Kwan Sik; Yang, Kyoung Hwa; Park, Jong Kil

    1997-01-01

    A vitrification process is under development in KEPRI for the treatment of low-and medium-level radioactive waste. Although the project is for developing and building Vitrification Pilot Plant in Korea, one of KEPRI's concerns is the quality control of the vitrified glass. This paper discusses a methodology for the estimation of glass composition by on-line measurement of molten glass properties, which could be applied to the plant for real-time quality control of the glass product. By remotely measuring viscosity and density of the molten glass, the glass characteristics such as composition can be estimated and eventually controlled. For this purpose, using the database of glass composition vs. physical properties in isothermal three-component system of SiO 2 -Na 2 O-B 2 O 3 , a software TERNARY has been developed which determines the glass composition by using two known physical properties (e.g. density and viscosity)

  6. Superductile bulk metallic glass

    International Nuclear Information System (INIS)

    Yao, K.F.; Ruan, F.; Yang, Y.Q.; Chen, N.

    2006-01-01

    Usually, monolithic bulk metallic glasses undergo inhomogeneous plastic deformation and exhibit poor ductility (<2%) at room temperature. We report a newly developed Pd-Si binary bulk metallic glass, which exhibits a uniform plastic deformation and a large plastic engineering strain of 82% and a plastic true strain of 170%, together with initial strain hardening, slight strain softening and final strain hardening characteristics. The uniform shear deformation and the ultrahigh plasticity are mainly attributed to strain hardening, which results from the nanoscale inhomogeneity due to liquid phase separation. The formed nanoscale inhomogeneity will hinder, deflect, and bifurcate the propagation of shear bands

  7. Aging in a Structural Glass

    OpenAIRE

    Kob, Walter; Barrat, Jean-Louis

    1998-01-01

    We discuss the relaxation dynamics of a simple structural glass which has been quenched below its glass transition temperature. We demonstrate that time correlation functions show strong aging effects and investigate in what way the fluctuation dissipation theorem is violated.

  8. Foam Glass for Construction Materials

    DEFF Research Database (Denmark)

    Petersen, Rasmus Rosenlund

    2016-01-01

    Foaming is commonly achieved by adding foaming agents such as metal oxides or metal carbonates to glass powder. At elevated temperature, the glass melt becomes viscous and the foaming agents decompose or react to form gas, causing a foamy glass melt. Subsequent cooling to room temperature, result...... in a solid foam glass. The foam glass industry employs a range of different melt precursors and foaming agents. Recycle glass is key melt precursors. Many parameters influence the foaming process and optimising the foaming conditions is very time consuming. The most challenging and attractive goal is to make...... low density foam glass for thermal insulation applications. In this thesis, it is argued that the use of metal carbonates as foaming agents is not suitable for low density foam glass. A reaction mechanism is proposed to justify this result. Furthermore, an in situ method is developed to optimise...

  9. Glass ceilings of professionalisation.

    Science.gov (United States)

    Stott, Dawn L

    2016-04-01

    The term glass ceiling is a political term often used to describe an unbreakable barrier that isnot visible with the human eye, but it keeps minorities from rising up i.e. it is a barrier to minoritygroups, in the past (and sometimes still) for women, that stops them from achieving theirtrue potential.

  10. What Glass Ceiling?

    Science.gov (United States)

    Lynch, Michael; Post, Katherine

    1996-01-01

    A recent study drawing on data from the Census Bureau and the Bureau of Labor Statistics suggests that the wage gap between men and women has virtually disappeared, and that the so-called "glass ceiling" results more from age and qualifications than from explicit discrimination. (SLD)

  11. Metallic glasses: structural models

    International Nuclear Information System (INIS)

    Nassif, E.

    1984-01-01

    The aim of this work is to give a summary of the attempts made up to the present in order to discribe by structural models the atomic arrangement in metallic glasses, showing also why the structure factors and atomic distribution functions cannot be always experimentally determined with a reasonable accuracy. (M.W.O.) [pt

  12. Microchips on glass

    NARCIS (Netherlands)

    Nanver, L.; De Vreede, L.; Keulemans, M.

    2007-01-01

    Microchips on glass. What about a mobile phone that uses a single microchip to receive all the available frequency bands, plus extras such as television, gps, and Internet access? Or, in due time, see-though implants that will monitor your state of health, and equipment that will let you see through

  13. Glass as matter

    DEFF Research Database (Denmark)

    Beim, Anne

    2000-01-01

    Refraiming the Moderns - Substitute Windows and Glass. In general terms, the seminar has contributed to the growing interest in the problems concerning the restoration of Modern Movement architecture. More particularly, it has of course drawn our attention to modern windows, which are increasingly...

  14. Glass ... current issues

    International Nuclear Information System (INIS)

    Wright, A.F.; Dupuy, J.

    1985-01-01

    The objectives of the School were twofold. Firstly to inform participants of actual and developing technological applications of glassy materials in which fundamental science makes a strong contribution, and secondly to bring together scientists from the widely different backgrounds of glass science and technology to promote mutual understanding and collaboration. (orig.)

  15. Stained Glass and Flu

    Centers for Disease Control (CDC) Podcasts

    2017-02-01

    Dr. Robert Webster, an Emeritus member of the Department of Infectious Diseases at St. Jude Children's Research Hospital, discusses his cover art story on stained glass and influenza.  Created: 2/1/2017 by National Center for Emerging and Zoonotic Infectious Diseases (NCEZID).   Date Released: 2/1/2017.

  16. Glasses and nuclear waste vitrification

    International Nuclear Information System (INIS)

    Ojovan, Michael I.

    2012-01-01

    Glass is an amorphous solid material which behaves like an isotropic crystal. Atomic structure of glass lacks long-range order but possesses short and most probably medium range order. Compared to crystalline materials of the same composition glasses are metastable materials however crystallisation processes are kinetically impeded within times which typically exceed the age of universe. The physical and chemical durability of glasses combined with their high tolerance to compositional changes makes glasses irreplaceable when hazardous waste needs immobilisation for safe long-term storage, transportation and consequent disposal. Immobilisation of radioactive waste in glassy materials using vitrification has been used successfully for several decades. Nuclear waste vitrification is attractive because of its flexibility, the large number of elements which can be incorporated in the glass, its high corrosion durability and the reduced volume of the resulting wasteform. Vitrification involves melting of waste materials with glass-forming additives so that the final vitreous product incorporates the waste contaminants in its macro- and micro-structure. Hazardous waste constituents are immobilised either by direct incorporation into the glass structure or by encapsulation when the final glassy material can be in form of a glass composite material. Both borosilicate and phosphate glasses are currently used to immobilise nuclear wastes. In addition to relatively homogeneous glasses novel glass composite materials are used to immobilise problematic waste streams. (author)

  17. Apollo 12 ropy glasses revisited

    Science.gov (United States)

    Wentworth, S. J.; Mckay, D. S.; Lindstrom, D. J.; Basu, A.; Martinez, R. R.; Bogard, D. D.; Garrison, D. H.

    1994-01-01

    We analyzed ropy glasses from Apollo 12 soils 12032 and 12033 by a variety of techniques including SEM/EDX, electron microprobe analysis, INAA, and Ar-39-Ar-40 age dating. The ropy glasses have potassium rare earth elements phosphorous (KREEP)-like compositions different from those of local Apollo 12 mare soils; it is likely that the ropy glasses are of exotic origin. Mixing calculations indicate that the ropy glasses formed from a liquid enriched in KREEP and that the ropy glass liquid also contained a significant amount of mare material. The presence of solar Ar and a trace of regolith-derived glass within the ropy glasses are evidence that the ropy glasses contain a small regolith component. Anorthosite and crystalline breccia (KREEP) clasts occur in some ropy glasses. We also found within these glasses clasts of felsite (fine-grained granitic fragments) very similar in texture and composition to the larger Apollo 12 felsites, which have a Ar-39-Ar-40 degassing age of 800 +/- 15 Ma. Measurements of 39-Ar-40-Ar in 12032 ropy glass indicate that it was degassed at the same time as the large felsite although the ropy glass was not completely degassed. The ropy glasses and felsites, therefore, probably came from the same source. Most early investigators suggested that the Apollo 12 ropy glasses were part of the ejecta deposited at the Apollo 12 site from the Copernicus impact. Our new data reinforce this model. If these ropy glasses are from Copernicus, they provide new clues to the nature of the target material at the Copernicus site, a part of the Moon that has not been sampled directly.

  18. Glass bead cultivation of fungi

    DEFF Research Database (Denmark)

    Droce, Aida; Sørensen, Jens Laurids; Giese, H.

    2013-01-01

    Production of bioactive compounds and enzymes from filamentous fungi is highly dependent on cultivation conditions. Here we present an easy way to cultivate filamentous fungi on glass beads that allow complete control of nutrient supply. Secondary metabolite production in Fusarium graminearum...... and Fusarium solani cultivated on agar plates, in shaking liquid culture or on glass beads was compared. Agar plate culture and glass bead cultivation yielded comparable results while liquid culture had lower production of secondary metabolites. RNA extraction from glass beads and liquid cultures was easier...... to specific nutrient factors. •Fungal growth on glass beads eases and improves fungal RNA extraction....

  19. Sodium diffusion in boroaluminosilicate glasses

    DEFF Research Database (Denmark)

    Smedskjaer, Morten M.; Zheng, Qiuju; Mauro, John C.

    2011-01-01

    of isothermal sodium diffusion in BAS glasses by ion exchange, inward diffusion, and tracer diffusion experiments. By varying the [SiO2]/[Al2O3] ratio of the glasses, different structural regimes of sodium behavior are accessed. We show that the mobility of the sodium ions decreases with increasing [SiO2]/[Al2O......Understanding the fundamentals of alkali diffusion in boroaluminosilicate (BAS) glasses is of critical importance for advanced glass applications, e.g., the production of chemically strengthened glass covers for personal electronic devices. Here, we investigate the composition dependence...

  20. Low thermal expansion glass ceramics

    CERN Document Server

    1995-01-01

    This book is one of a series reporting on international research and development activities conducted by the Schott group of companies With the series, Schott aims to provide an overview of its activities for scientists, engineers, and managers from all branches of industry worldwide where glasses and glass ceramics are of interest Each volume begins with a chapter providing a general idea of the current problems, results, and trends relating to the subjects treated This volume describes the fundamental principles, the manufacturing process, and applications of low thermal expansion glass ceramics The composition, structure, and stability of polycrystalline materials having a low thermal expansion are described, and it is shown how low thermal expansion glass ceramics can be manufactured from appropriately chosen glass compositions Examples illustrate the formation of this type of glass ceramic by utilizing normal production processes together with controlled crystallization Thus glass ceramics with thermal c...

  1. Fun with singing wine glasses

    Science.gov (United States)

    Boone, Christine; Galloway, Melodie; Ruiz, Michael J.

    2018-05-01

    A fun activity is presented using singing wine glasses for introductory physics students. Students tune a white wine glass and a red wine glass to as many semitones as possible by filling the glasses with the appropriate amounts of water. A smart phone app is used to measure the frequencies of equal-temperament tones. Then plots of frequency against water volume percent are made using a spreadsheet. Students can also play combinations of pitches with several glasses. A video (Ruiz 2018 Video: Singing glasses http://mjtruiz.com/ped/wineglasses/) is provided which includes an excerpt of a beautiful piece written for singing glasses and choir: Stars by Latvian composer Ēriks Ešenvalds.

  2. Bulk metallic glass matrix composites

    International Nuclear Information System (INIS)

    Choi-Yim, H.; Johnson, W.L.

    1997-01-01

    Composites with a bulk metallic glass matrix were synthesized and characterized. This was made possible by the recent development of bulk metallic glasses that exhibit high resistance to crystallization in the undercooled liquid state. In this letter, experimental methods for processing metallic glass composites are introduced. Three different bulk metallic glass forming alloys were used as the matrix materials. Both ceramics and metals were introduced as reinforcement into the metallic glass. The metallic glass matrix remained amorphous after adding up to a 30 vol% fraction of particles or short wires. X-ray diffraction patterns of the composites show only peaks from the second phase particles superimposed on the broad diffuse maxima from the amorphous phase. Optical micrographs reveal uniformly distributed particles in the matrix. The glass transition of the amorphous matrix and the crystallization behavior of the composites were studied by calorimetric methods. copyright 1997 American Institute of Physics

  3. The borosilicate glass for 'PAMELA'

    International Nuclear Information System (INIS)

    Schiewer, E.

    1986-01-01

    The low enriched waste concentrate (LEWC) stored at Mol, Belgium, will be solidified in the vitrification plant 'PAMELA'. An alkali-borosilicate glass was developed by the Hahn-Meitner-Institut, Berlin, which dissolves (11 +- 3)wt% waste oxides while providing sufficient flexibility for changes in the process parameters. The development of the glass labelled SM513LW11 is described. Important properties of the glass melt (viscosity, resistivity, formation of yellow phase) and of the glass (corrosion in aqueous solutions, crystallization) are reported. The corrosion data of this glass are similar to those of other HLW-glasses. Less than five wt% of crystalline material are produced upon cooling of large glass blocks. Crystallization does not affect the chemical durability. (Auth.)

  4. Production of glass or glass-ceramic to metal seals with the application of pressure

    Science.gov (United States)

    Kelly, Michael D.; Kramer, Daniel P.

    1987-11-10

    In a process for preparing a glass or glass-ceramic to metal seal comprising contacting the glass with the metal and heat-treating the glass and metal under conditions whereby the glass to metal seal is effected and, optionally, the glass is converted to a glass-ceramic, an improvement comprises carrying out the heat-treating step using hot isostatic pressing.

  5. Glasses for Mali

    CERN Multimedia

    PH Department

    2008-01-01

    We are collecting old pairs of glasses to take out to Mali, where they can be re-used by people there. The price for a pair of glasses can often exceed 3 months salary, so they are prohibitively expensive for many people. If you have any old spectacles you can donate, please put them in the special box in the ATLAS secretariat, Bldg.40-4-D01 before the Christmas closure on 19 December so we can take them with us when we leave for Africa at the end of the month. (more details in ATLAS e-news edition of 29 September 2008: http://atlas-service-enews.web.cern.ch/atlas-service-enews/news/news_mali.php) many thanks! Katharine Leney co-driver of the ATLAS car on the Charity Run to Mali

  6. Glass manufacturing through induction

    International Nuclear Information System (INIS)

    Boen, R.; Paya, B.; Roscini, M.; Fautrelle, Y.; Tuaz, F.; Delage, D.

    1991-01-01

    Oxides and glasses are electrical and thermal insulators, but show the characteristic of being weakly conductors of electricity when they are melt. It is then possible to heat them through HF induction. This interesting property allows the development of a melting process in cold crucible induction furnace. The process is being studied and developed by a consortium made up of CFEI, CEA Marcoule, ELECTRICITE DE FRANCE and MADYLAM laboratory. The studies include 2 parts: a) One experimental part to develop the technology and research for satisfying configurations, through a small size platform (10 to 30 kg/h). The long run continuous pouring melting tests made on different kinds of glass allow to go-on with industrial range units. b) One theoretical part to understand the magneto-thermo-hydraulic phenomenon hardly in relation with the heavy dependence of the physical characteristics (electrical and heat conductivities, viscosity) according to temperature. 6 refs., 4 figs [fr

  7. Glass matrix armor

    International Nuclear Information System (INIS)

    Calkins, N.C.

    1991-01-01

    This patent describes an armor system which utilizes glass. A plurality of constraint cells are mounted on a surface of a substrate, which is metal armor plate or a similar tough material, such that the cells almost completely cover the surface of the substrate. Each constraint cell has a projectile receiving wall parallel to the substrate surface and has sides which are perpendicular to and surround the perimeter of the receiving wall. The cells are mounted such that, in one embodiment, the substrate surface serves as a sixth side or closure for each cell. Each cell has inside of it a plate, termed the front plate, which is parallel to and in contact with substantially all of the insides surface of the receiving wall. The balance of each cell is completely filled with a projectile-abrading material consisting of glass and a ceramic material and, in certain embodiments, a polymeric material

  8. Breaking the glass ceiling.

    Science.gov (United States)

    Lazarus, A

    1997-03-01

    The glass ceiling is a form of organizational bias and discrimination that prevents qualified professionals from achieving positions of top governance and leadership. This article examines glass ceiling barriers that keep physicians from the upper reaches of management. While these factors apply mainly to women and minority physicians in academia, and are attributable to sexual harassment and discrimination, physicians as a class are frequently denied executive management positions. Such denial results from inadequate preparation for a career in health care administration. Important issues in the professional development of physician executives include mentoring, training and education, administrative experience, and cultural and personality factors. All of those must be considered when making the transition from medicine to management.

  9. HLW immobilization in glass

    International Nuclear Information System (INIS)

    Leroy, P.; Jacquet-Francillon, N.; Runge, S.

    1992-01-01

    The immobilization of High Level Waste in glass in France is a long history which started as early as in the 1950's. More than 30 years of Research and Development have been invested in that field. Two industrial facilities are operating (AVM and R7) and a third one (T7), under cold testing, is planned to start active operation in the mid-92. While vitrification has been demonstrated to be an industrially mastered process, the question of the quality of the final waste product, i.e. the HLW glass, must be addressed. The scope of the present paper is to focus on the latter point from both standpoints of the R and D and of the industrial reality

  10. Nuclear traces in glass

    International Nuclear Information System (INIS)

    Segovia A, M. de N.

    1978-01-01

    The charged particles produce, in dielectric materials, physical and chemical effects which make evident the damaged zone along the trajectory of the particle. This damaged zone is known as the latent trace. The latent traces can be enlarged by an etching of the detector material. This treatment attacks preferently the zones of the material where the charged particles have penetrated, producing concavities which can be observed through a low magnification optical microscope. These concavities are known as developed traces. In this work we describe the glass characteristics as a detector of the fission fragments traces. In the first chapter we present a summary of the existing basic theories to explain the formation of traces in solids. In the second chapter we describe the etching method used for the traces development. In the following chapters we determine some chatacteristics of the traces formed on the glass, such as: the development optimum time; the diameter variation of the traces and their density according to the temperature variation of the detector; the glass response to a radiation more penetrating than that of the fission fragments; the distribution of the developed traces and the existing relation between this ditribution and the fission fragments of 252 Cf energies. The method which has been used is simple and cheap and can be utilized in laboratories whose resources are limited. The commercial glass which has been employed allows the registration of the fission fragments and subsequently the realization of experiments which involve the counting of the traces as well as the identification of particles. (author)

  11. Amorphous gauge glass theory

    International Nuclear Information System (INIS)

    Nielsen, H.B.; Bennett, D.L.

    1987-08-01

    Assuming that a lattice gauge theory describes a fundamental attribute of Nature, it should be pointed out that such a theory in the form of a gauge glass is a weaker assumption than a regular lattice model in as much as it is not constrained by the imposition of translational invariance; translational invariance is, however, recovered approximately in the long wavelength or continuum limit. (orig./WL)

  12. Polyamorphism in metalic glass.

    Energy Technology Data Exchange (ETDEWEB)

    Sheng, H. W.; Liu, H. Z.; Cheng, Y. Q.; Wen, J.; Lee, P.L.; Luo, W.K.; Shastri, S.D.; Ma, E.; X-Ray Science Division; Johns Hopkins Univ.; Chinese Academy of Sciences

    2007-03-01

    A metal, or an alloy, can often exist in more than one crystal structure. The face-centered-cubic and body-centered-cubic forms of iron (or steel) are a familiar example of such polymorphism. When metallic materials are made in the amorphous form, is a parallel 'polyamorphism' possible? So far, polyamorphic phase transitions in the glassy state have been observed only in glasses involving directional and open (such as tetrahedral) coordination environments. Here, we report an in situ X-ray diffraction observation of a pressure-induced transition between two distinct amorphous polymorphs in a Ce{sub 55}Al{sub 45} metallic glass. The large density difference observed between the two polyamorphs is attributed to their different electronic and atomic structures, in particular the bond shortening revealed by ab initio modeling of the effects of f-electron delocalization. This discovery offers a new perspective of the amorphous state of metals, and has implications for understanding the structure, evolution and properties of metallic glasses and related liquids. Our work also opens a new avenue towards technologically useful amorphous alloys that are compositionally identical but with different thermodynamic, functional and rheological properties due to different bonding and structural characteristics.

  13. Diffusion in glass

    Energy Technology Data Exchange (ETDEWEB)

    Mubarak, A S

    1991-12-31

    Rutherford backscattering spectromertry technique (RBS) was used to characterize and investigate the depth distribution profiles of Ca-impurities of Ca-doped soda-time glass. The purposely added Ca-impurities were introduced inti the glass matrix by a normal ion exchange diffusion process. The measurements and analysis were performed using 2 MeV {sup 2}He{sup +} ions supplied from the University of Jordan Van de Graff acceierator (JOVAG). The normalized concetration versus depth profile distributions for the Ca-imourities were determined, both theoretically and experimentally. The theoretical treatment was carried out by setting up and soiving the diffusion equation under the conditions of the experiment. The resulting profiles are characterized by a compiementary error function. the theoretical treeatment was extended to include the various methods of enhancing the diffusion process, e.g. using an electric field. The diffusion coefficient, assumed constant, of the Ca-impurities exchanged in the soda-lime glass was determined to be 1.23 x 10{sup 13} cm{sup 2}/s. A comparison between theoretically and experimentally determined profiles is made and commented at, where several conclusions are drawn and suggestions for future work are mentioned. (author). 38 refs., 21 figs., 10 Tabs.

  14. Radiation shielding glass

    International Nuclear Information System (INIS)

    Kido, Kazuhiro; Ueda, Hajime.

    1997-01-01

    It was found that a glass composition comprising, as essential ingredients, SiO 2 , PbO, Gd 2 O 3 and alkali metal oxides can provide a shielding performance against electromagnetic waves, charged particles and neutrons. The present invention provides radiation shielding glass containing at least from 16 to 46wt% of SiO 2 , from 47 to 75wt% of PbO, from 1 to 10wt% of Gd 2 O 3 , from 0 to 3wt% of Li 2 O, from 0 to 7wt% of Na 2 O, from 0 to 7wt% of K 2 O provided that Li 2 O + Na 2 O + K 2 O is from 1 to 10wt%, B 2 O 3 is from 0 to 10wt%, CeO 2 is from 0 to 3wt%, As 2 O 3 is from 0 to 1wt% and Sb 2 O 3 is from 0 to 1wt%. Since the glass can shield electromagnetic waves, charged particles and neutrons simultaneously, radiation shielding windows can be designed and manufactured at a reduced thickness and by less constitutional numbers in a circumstance where they are present altogether. (T.M.)

  15. Helium behaviour in nuclear glasses

    International Nuclear Information System (INIS)

    Fares, T.

    2011-01-01

    The present thesis focuses on the study of helium behavior in R7T7 nuclear waste glass. Helium is generated by the minor actinides alpha decays incorporated in the glass matrix. Therefore, four types of materials were used in this work. These are non radioactive R7T7 glasses saturated with helium under pressure, glasses implanted with 3 He + ions, glasses doped with curium and glasses irradiated in nuclear reactor. The study of helium solubility in saturated R7T7 glass has shown that helium atoms are inserted in the glass free volume. The results yielded a solubility of about 10 16 at. cm -3 atm. -1 . The incorporation limit of helium in this type of glass has been determined; its value amounted to about 2*10 21 at. cm -3 , corresponding to 2.5 at.%. Diffusion studies have shown that the helium migration is controlled by the single population dissolved in the glass free volume. An ideal diffusion model was used to simulate the helium release data which allowed to determine diffusion coefficients obeying to the following Arrhenius law: D = D 0 exp(-E a /kBT), where D 0 = 2.2*10 -2 and 5.4*10 -3 cm 2 s -1 and E a = 0.61 eV for the helium saturated and the curium doped glass respectively. These results reflect a thermally activated diffusion mechanism which seems to be not influenced by the glass radiation damage and helium concentrations studied in the present work (up to 8*10 19 at. g -1 , corresponding to 0.1 at.%). Characterizations of the macroscopic, structural and microstructural properties of glasses irradiated in nuclear reactor did not reveal any impact associated with the presence of helium at high concentrations. The observed modifications i.e. a swelling of 0.7 %, a decrease in hardness by 38 %, an increase between 8 and 34 % of the fracture toughness and a stabilization of the glass structure under irradiation, were attributed to the glass nuclear damage induced by the irradiation in reactor. Characterizations by SEM and TEM of R7T7 glasses implanted

  16. Laboratory testing of LITCO glasses

    International Nuclear Information System (INIS)

    Ellison, A.; Wolf, S.; Buck, E.; Luo, J.S.; Dietz, N.; Bates, J.K.; Ebert, W.L.

    1995-01-01

    The purpose of this program is to measure, the intermediate and long-term durability of glasses developed by Lockheed Idaho Technology Co. (LITCO) for the immobilization of calcined radioactive wastes. The objective is to use accelerated corrosion tests as an aid in developing durable waste form compositions. This is a report of tests performed on two LITCO glass compositions, Formula 127 and Formula 532. The main avenue for release of radionuclides into the environment in a geologic repository is the reaction of a waste glass with ground water, which alters the glass and releases its components into solution. These stages in glass corrosion are analyzed by using accelerated laboratory tests in which the ratio of sample surface area to solution volume, SA/V, is varied. At low SA/V, the solution concentrations of glass corrosion products remain low and the reaction approaches the forward rate. At higher SA/V the solution approaches saturation levels for glass corrosion products. At very high SA/V the solution is rapidly saturated in glass corrosion products and secondary crystalline phases precipitate. Tests at very high SA/V provide information about the composition of the solution at saturation or, when no solution is recovered, the identities and the order of appearance of secondary crystalline phases. Tests were applied to Formula 127 and Formula 532 glasses to provide information about the interim and long-term stages in glass corrosion

  17. Glass containing radioactive nuclear waste

    International Nuclear Information System (INIS)

    Boatner, L.A.; Sales, B.C.

    1985-01-01

    Lead-iron phosphate glasses containing a high level of Fe 2 O 3 for use as a storage medium for high-level-radioactive nuclear waste. By combining lead-iron phosphate glass with various types of simulated high-level nuclear waste, a highly corrosion resistant, homogeneous, easily processed glass can be formed. For corroding solutions at 90 C, with solution pH values in the range between 5 and 9, the corrosion rate of the lead-iron phosphate nuclear waste glass is at least 10 2 to 10 3 times lower than the corrosion rate of a comparable borosilicate nuclear waste glass. The presence of Fe 2 O 3 in forming the lead-iron phosphate glass is critical. Lead-iron phosphate nuclear waste glass can be prepared at temperatures as low as 800 C, since they exhibit very low melt viscosities in the 800 to 1050 C temperature range. These waste-loaded glasses do not readily devitrify at temperatures as high as 550 C and are not adversely affected by large doses of gamma radiation in H 2 O at 135 C. The lead-iron phosphate waste glasses can be prepared with minimal modification of the technology developed for processing borosilicate glass nuclear waste forms. (author)

  18. Transferability of glass lens molding

    Science.gov (United States)

    Katsuki, Masahide

    2006-02-01

    Sphere lenses have been used for long time. But it is well known that sphere lenses theoretically have spherical aberration, coma and so on. And, aspheric lenses attract attention recently. Plastic lenses are molded easily with injection machines, and are relatively low cost. They are suitable for mass production. On the other hand, glass lenses have several excellent features such as high refractive index, heat resistance and so on. Many aspheric glass lenses came to be used for the latest digital camera and mobile phone camera module. It is very difficult to produce aspheric glass lenses by conventional process of curve generating and polishing. For the solution of this problem, Glass Molding Machine was developed and is spreading through the market. High precision mold is necessary to mold glass lenses with Glass Molding Machine. The mold core is ground or turned by high precision NC aspheric generator. To obtain higher transferability of the mold core, the function of the molding machine and the conditions of molding are very important. But because of high molding temperature, there are factors of thermal expansion and contraction of the mold and glass material. And it is hard to avoid the factors. In this session, I introduce following items. [1] Technology of glass molding and the machine is introduced. [2] The transferability of glass molding is analyzed with some data of glass lenses molded. [3] Compensation of molding shape error is discussed with examples.

  19. Analytical Plan for Roman Glasses

    Energy Technology Data Exchange (ETDEWEB)

    Strachan, Denis M.; Buck, Edgar C.; Mueller, Karl T.; Schwantes, Jon M.; Olszta, Matthew J.; Thevuthasan, Suntharampillai; Heeren, Ronald M.

    2011-01-01

    Roman glasses that have been in the sea or underground for about 1800 years can serve as the independent “experiment” that is needed for validation of codes and models that are used in performance assessment. Two sets of Roman-era glasses have been obtained for this purpose. One set comes from the sunken vessel the Iulia Felix; the second from recently excavated glasses from a Roman villa in Aquileia, Italy. The specimens contain glass artifacts and attached sediment or soil. In the case of the Iulia Felix glasses quite a lot of analytical work has been completed at the University of Padova, but from an archaeological perspective. The glasses from Aquileia have not been so carefully analyzed, but they are similar to other Roman glasses. Both glass and sediment or soil need to be analyzed and are the subject of this analytical plan. The glasses need to be analyzed with the goal of validating the model used to describe glass dissolution. The sediment and soil need to be analyzed to determine the profile of elements released from the glass. This latter need represents a significant analytical challenge because of the trace quantities that need to be analyzed. Both pieces of information will yield important information useful in the validation of the glass dissolution model and the chemical transport code(s) used to determine the migration of elements once released from the glass. In this plan, we outline the analytical techniques that should be useful in obtaining the needed information and suggest a useful starting point for this analytical effort.

  20. Bioactive glass in tissue engineering

    Science.gov (United States)

    Rahaman, Mohamed N.; Day, Delbert E.; Bal, B. Sonny; Fu, Qiang; Jung, Steven B.; Bonewald, Lynda F.; Tomsia, Antoni P.

    2011-01-01

    This review focuses on recent advances in the development and use of bioactive glass for tissue engineering applications. Despite its inherent brittleness, bioactive glass has several appealing characteristics as a scaffold material for bone tissue engineering. New bioactive glasses based on borate and borosilicate compositions have shown the ability to enhance new bone formation when compared to silicate bioactive glass. Borate-based bioactive glasses also have controllable degradation rates, so the degradation of the bioactive glass implant can be more closely matched to the rate of new bone formation. Bioactive glasses can be doped with trace quantities of elements such as Cu, Zn and Sr, which are known to be beneficial for healthy bone growth. In addition to the new bioactive glasses, recent advances in biomaterials processing have resulted in the creation of scaffold architectures with a range of mechanical properties suitable for the substitution of loaded as well as non-loaded bone. While bioactive glass has been extensively investigated for bone repair, there has been relatively little research on the application of bioactive glass to the repair of soft tissues. However, recent work has shown the ability of bioactive glass to promote angiogenesis, which is critical to numerous applications in tissue regeneration, such as neovascularization for bone regeneration and the healing of soft tissue wounds. Bioactive glass has also been shown to enhance neocartilage formation during in vitro culture of chondrocyte-seeded hydrogels, and to serve as a subchondral substrate for tissue-engineered osteochondral constructs. Methods used to manipulate the structure and performance of bioactive glass in these tissue engineering applications are analyzed. PMID:21421084

  1. NEW ERBIUM DOPED ANTIMONY GLASSES FOR LASER AND GLASS AMPLIFICATION

    Directory of Open Access Journals (Sweden)

    B. Tioua

    2015-07-01

    Full Text Available Because of the special spectroscopic properties of the rare earth ions, rare earth doped glasses are widely used in bulk and fiber lasers or amplifiers. The modelling of lasers and searching for new laser transitions require a precise knowledge of the spectroscopic properties of rare earth ions in different host glasses. In this poster will offer new doped erbium glasses synthesized in silicate crucibles were obtained in the combination Sb2O3-WO3-Na2O. Several properties are measured and correlated with glass compositions. The absorption spectral studies have been performed for erbium doped glasses. The intensities of various absorption bands of the doped glasses are measured and the Judd-Ofelt parameters have been computed. From the theory of Judd-Ofelt, various radiative properties, such as transition probability, branching ratio and radiative life time for various emission levels of these doped glasses have been determined and reported. These results confirm the ability of antimony glasses for glass amplification.

  2. Mechanical failure and glass transition in metallic glasses

    International Nuclear Information System (INIS)

    Egami, T.

    2011-01-01

    Research highlights: → We review the recent results of molecular dynamics simulations on metallic glasses. → They show the equivalence of mechanical failure and glass transition. → We discuss the microscopic mechanism behind this equivalence. → We show that the density of defects in metallic glasses is as high as a quarter. → Our concepts about the defect state in glasses need to be changed. - Abstract: The current majority view on the phenomenon of mechanical failure in metallic glasses appears to be that it is caused by the activity of some structural defects, such as free-volumes or shear transformation zones, and the concentration of such defects is small, only of the order of 1%. However, the recent results compel us to revise this view. Through molecular dynamics simulation it has been shown that mechanical failure is the stress-induced glass transition. According to our theory the concentration of the liquid-like sites (defects) is well over 20% at the glass transition. We suggest that the defect concentration in metallic glasses is actually very high, and percolation of such defects causes atomic avalanche and mechanical failure. In this article we discuss the glass transition, mechanical failure and viscosity from such a point of view.

  3. Influence of Glass Property Restrictions on Hanford HLW Glass Volume

    International Nuclear Information System (INIS)

    Kim, Dong-Sang; Vienna, John D.

    2001-01-01

    A systematic evaluation of Hanford High-Level Waste (HLW) loading in alkali-alumino-borosilicate glasses was performed. The waste feed compositions used were obtained from current tank waste composition estimates, Hanford's baseline retrieval sequence, and pretreatment processes. The waste feeds were sorted into groups of like composition by cluster analysis. Glass composition optimization was performed on each cluster to meet property and composition constraints while maximizing waste loading. Glass properties were estimated using property models developed for Hanford HLW glasses. The impacts of many constraints on the volume of HLW glass to be produced at Hanford were evaluated. The liquidus temperature, melting temperature, chromium concentration, formation of multiple phases on cooling, and product consistency test response requirements for the glass were varied one- or many-at-a-time and the resultant glass volume was calculated. This study shows clearly that the allowance of crystalline phases in the glass melter can significantly decrease the volume of HLW glass to be produced at Hanford.

  4. Analysis of glass fibre sizing

    DEFF Research Database (Denmark)

    Petersen, Helga Nørgaard; Kusano, Yukihiro; Brøndsted, Povl

    2014-01-01

    Glass fibre reinforced polymer composites are widely used for industrial and engineering applications which include construction, aerospace, automotive and wind energy industry. During the manufacturing glass fibres, they are surface-treated with an aqueous solution. This process and the treated...... surfaces are called sizing. The sizing influences the properties of the interface between fibres and a matrix, and subsequently affects mechanical properties of composites. In this work the sizing of commercially available glass fibres was analysed so as to study the composition and chemical structures....... Soxhlet extraction was used to extract components of the sizing from the glass fibres. The glass fibres, their extracts and coated glass plates were analysed by Thermo-Gravimetric Analysis combined with a mass spectrometer (TGA-MS), and Attenuated Total Reflectance Fourier Transform Infrared (ATR...

  5. Low Thermal Expansion Glass Ceramics

    CERN Document Server

    Bach, Hans

    2005-01-01

    This book appears in the authoritative series reporting the international research and development activities conducted by the Schott group of companies. This series provides an overview of Schott's activities for scientists, engineers, and managers from all branches of industry worldwide in which glasses and glass ceramics are of interest. Each volume begins with a chapter providing a general idea of the current problems, results, and trends relating to the subjects treated. This new extended edition describes the fundamental principles, the manufacturing process, and applications of low thermal expansion glass ceramics. The composition, structure, and stability of polycrystalline materials having a low thermal expansion are described, and it is shown how low thermal expansion glass ceramics can be manufactured from appropriately chosen glass compositions. Examples illustrate the formation of this type of glass ceramic by utilizing normal production processes together with controlled crystallization. Thus g...

  6. Complexity of Curved Glass Structures

    Science.gov (United States)

    Kosić, T.; Svetel, I.; Cekić, Z.

    2017-11-01

    Despite the increasing number of research on the architectural structures of curvilinear forms and technological and practical improvement of the glass production observed over recent years, there is still a lack of comprehensive codes and standards, recommendations and experience data linked to real-life curved glass structures applications regarding design, manufacture, use, performance and economy. However, more and more complex buildings and structures with the large areas of glass envelope geometrically complex shape are built every year. The aim of the presented research is to collect data on the existing design philosophy on curved glass structure cases. The investigation includes a survey about how architects and engineers deal with different design aspects of curved glass structures with a special focus on the design and construction process, glass types and structural and fixing systems. The current paper gives a brief overview of the survey findings.

  7. Electronic structure of metallic glasses

    International Nuclear Information System (INIS)

    Oelhafen, P.; Lapka, R.; Gubler, U.; Krieg, J.; DasGupta, A.; Guentherodt, H.J.; Mizoguchi, T.; Hague, C.; Kuebler, J.; Nagel, S.R.

    1981-01-01

    This paper is organized in six sections and deals with (1) the glassy transition metal alloys, their d-band structure, the d-band shifts on alloying and their relation to the alloy heat of formation (ΔH) and the glass forming ability, (2) the glass to crystal phase transition viewed by valence band spectroscopy, (3) band structure calculations, (4) metallic glasses prepared by laser glazing, (5) glassy normal metal alloys, and (6) glassy hydrides

  8. PLZT capacitor on glass substrate

    Science.gov (United States)

    Fairchild, M. Ray; Taylor, Ralph S.; Berlin, Carl W.; Wong, Celine W. K.; Ma, Beihai; Balachandran, Uthamalingam

    2016-01-05

    A lead-lanthanum-zirconium-titanate (PLZT) capacitor on a substrate formed of glass. The first metallization layer is deposited on a top side of the substrate to form a first electrode. The dielectric layer of PLZT is deposited over the first metallization layer. The second metallization layer deposited over the dielectric layer to form a second electrode. The glass substrate is advantageous as glass is compatible with an annealing process used to form the capacitor.

  9. Glass corrosion in natural environments

    Science.gov (United States)

    Thorpe, Arthur N.; Barkatt, Aaron

    1992-01-01

    Experiments carried out during the progress period are summarized. Experiments carried out involving glass samples exposed to solutions of Tris have shown the appearance of 'spikes' upon monitoring glass dissolution as a function of time. The periodic 'spikes' observed in Tris-based media were interpreted in terms of cracking due to excessive stress in the surface region of the glass. Studies of the interactions of silicate glasses with metal ions in buffered media were extended to systems containing Al. Caps buffer was used to establish the pH. The procedures used are described and the results are given. Preliminary studies were initiated as to the feasibility of adding a slowly dissolving solid compound of the additive to the glass-water system to maintain a supply of dissolved additive. It appears that several magnesium compounds have a suitable combination of solubility and affinity towards silicate glass surfaces to have a pronounced retarding effect on the extraction of uranium from the glass. These preliminary findings raise the possibility that introducing a magnesium source into geologic repositories for nuclear waste glass in the form of a sparingly soluble Mg-based backfill material may cause a substantial reduction in the extent of long-term glass corrosion. The studies described also provide mechanistic understanding of the roles of various metal solutes in the leachant. Such understanding forms the basis for developing long-term predictions of nuclear waste glass durability under repository conditions. From what is known about natural highly reduced glasses such as tektites, it is clear that iron is dissolved as ferrous iron with little or no ferric iron. The reducing conditions were high enough to cause metallic iron to exsolve out of the glass in the form of submicroscopic spherules. As the nuclear waste glass is much less reduced, a study was initiated on other natural glasses in addition to the nuclear waste glass. Extensive measurements were

  10. Crystallization of copper metaphosphate glass

    Science.gov (United States)

    Bae, Byeong-Soo; Weinberg, Michael C.

    1993-01-01

    The effect of the valence state of copper in copper metaphosphate glass on the crystallization behavior and glass transition temperature has been investigated. The crystallization of copper metaphosphate is initiated from the surface and its main crystalline phase is copper metaphosphate (Cu(PO)3),independent of the (Cu sup 2+)/(Cu(total)). However, the crystal morphology, the relative crystallization rates, and their temperature dependences are affected by the (Cu sup 2+)/(Cu (total)) ratio in the glass. On the other hand, the totally oxidized glass crystallizes from all over the surface. The relative crystallization rate of the reduced glass to the totally oxidized glass is large at low temperature, but small at high temperature. The glass transition temperature of the glass increases as the (Cu sup 2+)/(Cu(total)) ratio is raised. It is also found that the atmosphere used during heat treatment does not influence the crystallization of the reduced glass, except for the formation of a very thin CuO surface layer when heated in air.

  11. Fabrication of Radiation Shielding Glass

    International Nuclear Information System (INIS)

    Tavichai, Nattaya; Pormsean, Suriyont; Dararutana, Pisutti; Sirikulrat, Narin

    2003-06-01

    In this work, lead glass doped with 50%, 55%,60%, 65%, and 70% w/w Pb 3 O 4 . After that, glass mixtures were melt at 1,250οC with 4 hours soaking time. Molten glass was shaped by mould casting technique then annealed at 700οC and cooled down to room temperature. It was found that the glass with 60%w/w Pb 3 O 4 show maximum absorption coefficient of about 0.383 cm -1 with I-131 at energy 364 keV. The observed refractive indices of the samples range between 1.5908 to 1.5922

  12. Compositional threshold for Nuclear Waste Glass Durability

    International Nuclear Information System (INIS)

    Kruger, Albert A.; Farooqi, Rahmatullah; Hrma, Pavel R.

    2013-01-01

    Within the composition space of glasses, a distinct threshold appears to exist that separates 'good' glasses, i.e., those which are sufficiently durable, from 'bad' glasses of a low durability. The objective of our research is to clarify the origin of this threshold by exploring the relationship between glass composition, glass structure and chemical durability around the threshold region

  13. Restorative Glass : Reversible, discreet restoration using structural glass components

    NARCIS (Netherlands)

    Oikonomopoulou, F.; Bristogianni, T.; Barou, L.; van Hees, R.P.J.; Nijsse, R.; Veer, F.A.; Henk, Schellen; van Schijndel, Jos

    2016-01-01

    The application of structural glass as the principal material in restoration and conservation practices is a distinguishable, yet discreet approach. The transparency of glass allows the simultaneous perception of the monument at both its original and present condition, preserving its historical and

  14. New Erbium Doped Antimony Glasses for Laser and Glass ...

    African Journals Online (AJOL)

    Because of the special spectroscopic properties of the rare earth ions, rare earth doped glasses are widely used in bulk and fiber lasers or amplifiers. The modelling of lasers and searching for new laser transitions require a precise knowledge of the spectroscopic properties of rare earth ions in different host glasses.

  15. The glass sphinx: a massive stacked glass structure

    NARCIS (Netherlands)

    Bos, F.P.; Heijden, van der T.; Schreurs, P.; Bos, F.; Louter, C.; Nijsse, R.; Veer, F.

    The refurbishment of the Meuse river boulevard in Venlo instigated Scheuten Glass to donate a giant-sized, 6 metre high version of the stacked glass statue the Sphinx, which had originally been made as a 80 cm sculpture to commemorate the city's 650th anniversary back in 1993. Many hurdles had to be

  16. Structural Glass Beams with Embedded Glass Fibre Reinforcement

    NARCIS (Netherlands)

    Louter, P.C.; Leung, Calvin; Kolstein, M.H.; Vambersky, J.N.J.A.; Bos, Freek; Louter, Pieter Christiaan; Veer, Fred

    2010-01-01

    This paper investigates the possibilities of pultruded glass fibre rods as embedded reinforcement in SentryGlas (SG) laminated glass beams. To do so, a series of pullout tests, to investigate the bond strength of the rods to the laminate, and a series of beam tests, to investigate the post-breakage

  17. Glass ceramic fibres

    International Nuclear Information System (INIS)

    Blaschek, O.; Paulitsch, P.

    1983-01-01

    As the correlation between mineralogical phase and chemical composition influences the type of application at different high temperatures, we studied the mineralogical phases of nine crystal glass fibres of the temperature ranges 1 150 degrees Celsius (Type 1), 1 400 degrees Celsius (Type 2) and 1 500 degrees Celsius (Type 3) at various high temperatures. The methods used in the study were microscopy, X-ray diffraction, transmission electron microscopy and differential thermal analysis. The investigations showed that mullite forms in glassy fibres of the system Al 2 O 3 . SiO 2 from 850 degrees Celsius to 990 degrees Celsius as 2/1 mullite; 3/2 mullite appeared above 990 degrees Celsius besides the crystallization of cristobalite. Fibres with 95 per cent Al 2 O 3 include the phases delta-Al 2 O 3 and alpha- Al 2 O 3 and mullite. Delta- Al 2 O 3 is stable up to 1 100 degrees Celsius. Alpha-Al 2 O 3 and mullite are only stable phases at 1 400 degrees Celsius. These different crystal phases influence the quality of the technical fibre according to the stability field of glass and crystals. This study has determined that it is possible to identify different fibres from different productions by their mineralogical compositions and to relate them to the high temperature application

  18. Spheroidization of glass powders for glass ionomer cements.

    Science.gov (United States)

    Gu, Y W; Yap, A U J; Cheang, P; Kumar, R

    2004-08-01

    Commercial angular glass powders were spheroidized using both the flame spraying and inductively coupled radio frequency plasma spraying techniques. Spherical powders with different particle size distributions were obtained after spheroidization. The effects of spherical glass powders on the mechanical properties of glass ionomer cements (GICs) were investigated. Results showed that the particle size distribution of the glass powders had a significant influence on the mechanical properties of GICs. Powders with a bimodal particle size distribution ensured a high packing density of glass ionomer cements, giving relatively high mechanical properties of GICs. GICs prepared by flame-spheroidized powders showed low strength values due to the loss of fine particles during flame spraying, leading to a low packing density and few metal ions reacting with polyacrylic acid to form cross-linking. GICs prepared by the nano-sized powders showed low strength because of the low bulk density of the nano-sized powders and hence low powder/liquid ratio of GICs.

  19. Characterization and Morphological Properties of Glass Fiber ...

    African Journals Online (AJOL)

    PROF HORSFALL

    used as the matrix for the glass fibre-epoxy resin formation. E- Glass fibre ... reinforcement of composites, coatings of materials, and other ..... composite for the manufacture of glass-ceramic materials ... reinforced epoxy composites with carbon.

  20. Optical properties of alkaline earth borate glasses

    African Journals Online (AJOL)

    user

    The alkaline earth borate glasses containing heavy metal oxides show good solubility of rare-earth ions. Glasses containing PbO exhibit low glass transition temperature (Tg) and high ..... These oxygen ions carry a partial negative charge and.

  1. Optical properties of alkaline earth borate glasses

    African Journals Online (AJOL)

    user

    ... devices; radiation shields, surgical lasers and their glass ceramic counter ... Alkaline earth oxides improve glass forming capability while heavy metal ... reports on optical properties of MO-B2O3 glasses containing alkaline earth oxides.

  2. Properties of gallium lanthanum sulphide glass

    OpenAIRE

    Bastock, P.; Craig, C.; Khan, K.; Weatherby, E.; Yao, J.; Hewak, D.W.

    2015-01-01

    A series of gallium lanthanum sulphide (GLS) glasses has been studied in order to ascertain properties across the entire glass forming region. This is the first comprehensive study of GLS glass over a wide compositional range.

  3. Who will buy smart glasses?

    DEFF Research Database (Denmark)

    Rauschnabel, Philipp; Brem, Alexander; Ivens, Bjørn S.

    2015-01-01

    Recent market studies reveal that augmented reality (AR) devices, such as smart glasses, will substantially influence the media landscape. Yet, little is known about the intended adoption of smart glasses, particularly: Who are the early adopters of such wearables? We contribute to the growing bo...

  4. Superconductive analogue of spin glasses

    International Nuclear Information System (INIS)

    Feigel'man, M.; Ioffe, L.; Vinokur, V.; Larkin, A.

    1987-07-01

    The properties of granular superconductors in magnetic fields, namely the existence of a new superconductive state analogue of the low-temperature superconductive state in spin glasses are discussed in the frame of the infinite-range model and the finite-range models. Experiments for elucidation of spin-glass superconductive state in real systems are suggested. 30 refs

  5. Zirconium based bulk metallic glasses

    International Nuclear Information System (INIS)

    Dey, G.K.; Neogy, S.; Savalia, R.T.; Tewari, R.; Srivastava, D.; Banerjee, S.

    2006-01-01

    Metallic glasses have come into prominence in recent times because their nanocrystalline atomic arrangement imparts many useful and unusual properties to these metallic solids. In this study, bulk glasses have been obtained in Zr based multicomponent alloy by induction melting these alloys in silica crucibles and casting these in form of rods 3 and 6 mm in diameter in a copper mould

  6. International Congress on Glass XII

    Energy Technology Data Exchange (ETDEWEB)

    Doremus, R H; LaCourse, W C; Mackenzie, J D; Varner, J R; Wolf, W W [eds.

    1980-01-01

    A total of 158 papers are included under nine headings: structure and glass formation; optical properties; electrical and magnetic properties; mechanical properties and relaxation; mass transport; chemical durability and surfaces; nucleation; crystallization; and glass ceramics; processing; and automatic controls. Separate abstracts were prepared for eight papers; four of the remaining papers had been processed previously for the data base. (DLC)

  7. OPAL Various Lead Glass Blocks

    CERN Multimedia

    These lead glass blocks were part of a CERN detector called OPAL (one of the four experiments at the LEP particle detector). OPAL uses some 12 000 blocks of glass like this to measure particle energies in the electromagnetic calorimeter. This detector measured the energy deposited when electrons and photons were slowed down and stopped.

  8. Lead-iron phosophate glass

    International Nuclear Information System (INIS)

    Sales, B.C.; Boatner, L.A.

    1988-01-01

    The lead-iron phosphate nuclear waste glasses (LIPNWG) are the subject of the present chapter. They were discovered in 1984 while the authors were attempting to find a sintering aid for certain types of crystalline monazite ceramic high-level nuclear waste forms. In the present chapter, the term waste glass is synonymous with nuclear waste glass (NWG), and the acronym LIP is often used for lead-iron phosphate. Lead-iron phosphate glasses, like many of the previously studied phosphate glasses, are corrosion resistant in aqueous solutions at temperatures below 100 degrees C, and they can be melted and poured at temperatures that are relatively low in comparison with the processing temperatures required for current silicate glass compositions. Unlike the phosphate glasses investigated previously, however, LIPNWGs do not suffer from alteration due to devitrification during realistic and readily, achievable cooling periods. Additionally, lead-iron phosphate glass melts are not nearly as corrosive as the sodium phosphate melts investigated during the 1960s; and, therefore, they can be melted and processed using crucibles made from a variety of materials

  9. Plutonium dioxide dissolution in glass

    Energy Technology Data Exchange (ETDEWEB)

    Vienna, J.D.; Alexander, D.L.; Li, Hong [and others

    1996-09-01

    In the aftermath of the Cold War, the U.S. Department of Energy`s (DOE) Office of Fissile Materials Disposition (OFMD) is charged with providing technical support for evaluation of disposition options for excess fissile materials manufactured for the nation`s defense. One option being considered for the disposition of excess plutonium (Pu) is immobilization by vitrification. The vitrification option entails immobilizing Pu in a host glass and waste package that are criticality-safe (immune to nuclear criticality), proliferation-resistant, and environmentally acceptable for long-term storage or disposal. To prove the technical and economic feasibility of candidate vitrification options it is necessary to demonstrate that PuO{sub 2} feedstock can be dissolved in glass in sufficient quantity. The OFMD immobilization program has set a Pu solubility goal of 10 wt% in glass. The life cycle cost of the vitrification options are strongly influenced by the rate at which PUO{sub 2} dissolves in glass. The total number of process lines needed for vitrification of 50 t of Pu in 10 years is directly dependent upon the time required for Pu dissolution in glass. The objective of this joint Pacific Northwest National Laboratory (PNNL) - Savannah River Technology Center (SRTC) study was to demonstrate a high Pu solubility in glass and to identify on a rough scale the time required for Pu dissolution in the glass. This study was conducted using a lanthanide borosilicate (LaBS) glass composition designed at the SRTC for the vitrification of actinides.

  10. Radiation effects in silicate glasses

    International Nuclear Information System (INIS)

    Bibler, N.E.; Howitt, D.G.

    1988-01-01

    The study of radiation effects in complex silicate glasses has received renewed attention because of their use in special applications such as high level nuclear waste immobilization and fiber optics. Radiation changes the properties of these glasses by altering their electronic and atomic configurations. These alterations or defects may cause dilatations or microscopic phase changes along with absorption centers that limit the optical application of the glasses. Atomic displacements induced in the already disordered structure of the glasses may affect their use where heavy irradiating particles such as alpha particles, alpha recoils, fission fragments, or accelerated ions are present. Large changes (up to 1%) in density may result. In some cases the radiation damage may be severe enough to affect the durability of the glass in aqueous solutions. In the paper, the authors review the literature concerning radiation effects on density, durability, stored energy, microstructure and optical properties of silicate glasses. Both simple glasses and complex glasses used for immobilization of nuclear waste are considered

  11. Plutonium dioxide dissolution in glass

    International Nuclear Information System (INIS)

    Vienna, J.D.; Alexander, D.L.; Li, Hong

    1996-09-01

    In the aftermath of the Cold War, the U.S. Department of Energy's (DOE) Office of Fissile Materials Disposition (OFMD) is charged with providing technical support for evaluation of disposition options for excess fissile materials manufactured for the nation's defense. One option being considered for the disposition of excess plutonium (Pu) is immobilization by vitrification. The vitrification option entails immobilizing Pu in a host glass and waste package that are criticality-safe (immune to nuclear criticality), proliferation-resistant, and environmentally acceptable for long-term storage or disposal. To prove the technical and economic feasibility of candidate vitrification options it is necessary to demonstrate that PuO 2 feedstock can be dissolved in glass in sufficient quantity. The OFMD immobilization program has set a Pu solubility goal of 10 wt% in glass. The life cycle cost of the vitrification options are strongly influenced by the rate at which PUO 2 dissolves in glass. The total number of process lines needed for vitrification of 50 t of Pu in 10 years is directly dependent upon the time required for Pu dissolution in glass. The objective of this joint Pacific Northwest National Laboratory (PNNL) - Savannah River Technology Center (SRTC) study was to demonstrate a high Pu solubility in glass and to identify on a rough scale the time required for Pu dissolution in the glass. This study was conducted using a lanthanide borosilicate (LaBS) glass composition designed at the SRTC for the vitrification of actinides

  12. Phonon scattering in metallic glasses

    International Nuclear Information System (INIS)

    Black, J.L.

    1979-01-01

    The purpose of this article is to review some recent theoretical and experimental developments in the study of metallic glasses at temperatures near or below 1K. In this temperature regime, it appears that practically all glasses, whether metallic or insulating, behave in a similar fashion. The fact that such similarities occur, despite substantial structural differences between metallic and insulating glasses, constitutes a major theoretical challenge. This challenge, however, is not directly addressed in what follows. Instead, the evidence for universal behavior and the theory which is necessary to understand this evidence are emphasized. It turns out that most of this evidence involves a comparison of phonon scattering in metallic glasses with its counterpart in insulating glasses

  13. Glass Ceramic Formulation Data Package

    International Nuclear Information System (INIS)

    Crum, Jarrod V.; Rodriguez, Carmen P.; McCloy, John S.; Vienna, John D.; Chung, Chul-Woo

    2012-01-01

    A glass ceramic waste form is being developed for treatment of secondary waste streams generated by aqueous reprocessing of commercial used nuclear fuel (Crum et al. 2012b). The waste stream contains a mixture of transition metals, alkali, alkaline earths, and lanthanides, several of which exceed the solubility limits of a single phase borosilicate glass (Crum et al. 2009; Caurant et al. 2007). A multi-phase glass ceramic waste form allows incorporation of insoluble components of the waste by designed crystallization into durable heat tolerant phases. The glass ceramic formulation and processing targets the formation of the following three stable crystalline phases: (1) powellite (XMoO4) where X can be (Ca, Sr, Ba, and/or Ln), (2) oxyapatite Yx,Z(10-x)Si6O26 where Y is alkaline earth, Z is Ln, and (3) lanthanide borosilicate (Ln5BSi2O13). These three phases incorporate the waste components that are above the solubility limit of a single-phase borosilicate glass. The glass ceramic is designed to be a single phase melt, just like a borosilicate glass, and then crystallize upon slow cooling to form the targeted phases. The slow cooling schedule is based on the centerline cooling profile of a 2 foot diameter canister such as the Hanford High-Level Waste canister. Up to this point, crucible testing has been used for glass ceramic development, with cold crucible induction melter (CCIM) targeted as the ultimate processing technology for the waste form. Idaho National Laboratory (INL) will conduct a scaled CCIM test in FY2012 with a glass ceramic to demonstrate the processing behavior. This Data Package documents the laboratory studies of the glass ceramic composition to support the CCIM test. Pacific Northwest National Laboratory (PNNL) measured melt viscosity, electrical conductivity, and crystallization behavior upon cooling to identify a processing window (temperature range) for melter operation and cooling profiles necessary to crystallize the targeted phases in the

  14. Database and Interim Glass Property Models for Hanford HLW Glasses

    International Nuclear Information System (INIS)

    Hrma, Pavel R; Piepel, Gregory F; Vienna, John D; Cooley, Scott K; Kim, Dong-Sang; Russell, Renee L

    2001-01-01

    The purpose of this report is to provide a methodology for an increase in the efficiency and a decrease in the cost of vitrifying high-level waste (HLW) by optimizing HLW glass formulation. This methodology consists in collecting and generating a database of glass properties that determine HLW glass processability and acceptability and relating these properties to glass composition. The report explains how the property-composition models are developed, fitted to data, used for glass formulation optimization, and continuously updated in response to changes in HLW composition estimates and changes in glass processing technology. Further, the report reviews the glass property-composition literature data and presents their preliminary critical evaluation and screening. Finally the report provides interim property-composition models for melt viscosity, for liquidus temperature (with spinel and zircon primary crystalline phases), and for the product consistency test normalized releases of B, Na, and Li. Models were fitted to a subset of the screened database deemed most relevant for the current HLW composition region

  15. Glass science tutorial: Lecture No. 7, Waste glass technology for Hanford

    International Nuclear Information System (INIS)

    Kruger, A.A.

    1995-07-01

    This paper presents the details of the waste glass tutorial session that was held to promote knowledge of waste glass technology and how this can be used at the Hanford Reservation. Topics discussed include: glass properties; statistical approach to glass development; processing properties of nuclear waste glass; glass composition and the effects of composition on durability; model comparisons of free energy of hydration; LLW glass structure; glass crystallization; amorphous phase separation; corrosion of refractories and electrodes in waste glass melters; and glass formulation for maximum waste loading

  16. Joints in Tempered Glass Using Glass Dowel Discs

    DEFF Research Database (Denmark)

    Nielsen, Jens Henrik; Poulsen, Peter Noe

    One of the major reasons for using glass in structures is its transparency; however, traditional mechanical joints such as friction joints and steel dowel pinned connections are compromising the transparency. The present paper describes a novel joint which is practically maintaining the complete...... transparency of the glass. This is achieved by using a dowel disc made entirely of tempered glass. The concept of the joint is proved by pilot tests and numerical models. From the work it is seen that the load-carrying capacity of such a connection is similar to what is found for traditionally in-plane loaded...

  17. Glass packages in interim storage

    International Nuclear Information System (INIS)

    Jacquet-Francillon, N.

    1994-10-01

    This report summarize the current state of knowledge concerning the behavior of type C waste packages consisting of vitrified high-level solutions produced by reprocessing spent fuel. The composition and the physical and chemical properties of the feed solutions are reviewed, and the vitrification process is described. Sodium alumino-borosilicate glass compositions are generally employed - the glass used at la Hague for LWR fuel solutions, for example, contains 45 % SiO 2 . The major physical, chemical, mechanical and thermal properties of the glass are reviewed. In order to allow their thermal power to diminish, the 3630 glass packages produced (as of January 1993) in the vitrification facilities at Marcoule and La Hague are placed in interim storage for several decades. The actual interim storage period has not been defined, as it is closely related to the concept and organization selected for the final destination of the packages: a geological repository. The glass behavior under irradiation is described. Considerable basic and applied research has been conducted to assess the aqueous leaching behavior of nuclear containment glass. The effects of various repository parameters (temperature, flow rate, nature of the environmental materials) have been investigated. The experimental findings have been used to specify a model describing the kinetics of aqueous corrosion of the glass. More generally all the ''source term'' models developed in France by the CEA or by ANDRA are summarized. (author). 152 refs., 33 figs

  18. Glass ceramic seals to inconel

    Science.gov (United States)

    McCollister, Howard L.; Reed, Scott T.

    1983-11-08

    A glass ceramic composition prepared by subjecting a glass composition comprising, by weight, 65-80% SiO.sub.2, 8-16%, Li.sub.2 O, 2-8% , Al.sub.2 O.sub.3, 1-8% K.sub.2 O, 1-5% P.sub.2 O.sub.5 and 1.5-7% B.sub.2 O.sub.3, to the following processing steps of heating the glass composition to a temperature sufficient to crystallize lithium metasilicate therein, holding the glass composition at a temperature and for a time period sufficient to dissolve the lithium metasilicate therein thereby creating cristobalite nucleii, cooling the glass composition and maintaining the composition at a temperature and for a time period sufficient to recrystallize lithium metasilicate therein, and thermally treating the glass composition at a temperature and for a time period sufficient to cause growth of cristobalite and further crystallization of lithium metasilicate producing a glass ceramic composition having a specific thermal expansion coefficient and products containing said composition.

  19. Photoluminescence properties of the Eu-doped alpha-Al2O3 microspheres

    International Nuclear Information System (INIS)

    Liu, Dianguang; Zhu, Zhenfeng

    2014-01-01

    Highlights: • Al 2 O 3 :Eu 3+ phosphors were prepared via a microwave solvothermal route. • The particles were hierarchically nanostructured microspheres packaged by nanosheets. • The powders presented excellent orange–red emission when excited at 393 nm. • Critical concentration and distance of Eu 3+ in Al 2 O 3 is 0.007, 18 Å, respectively. -- Abstract: Al 2 O 3 :Eu 3+ samples were synthesized via microwave solvothermal method and thermal decomposition of Eu 3+ doped precursors. The sample characterizations were carried out by means of X-ray diffraction (XRD), scanning electron microscope (SEM) and photoluminescence (PL) spectra. XRD results indicated that Eu 3+ doped samples were most of α-Al 2 O 3 phase after being calcined at 1473 K. SEM results showed that the obtained α-Al 2 O 3 based powders via microwave solvothermal method were microspheres with an average diameter about 1.6 μm. PL spectra showed that upon excitation at 393 nm, the orange–red emission bands at the wavelength longer than 560 nm were from 5 D 0 → 7 F J (J = 1, 2) transitions. The asymmetry ratio of ( 5 D 0 → 7 F 2 )/( 5 D 0 → 7 F 1 ) intensity is about 1 and this value suggests that Eu 3+ ions occupy the same ratio of symmetry and asymmetry sites. It is shown that the 0.7 mol% of doping concentration of Eu 3+ ions in α-Al 2 O 3 :Eu 3+ is optimum. According to Dexter’s theory, the critical distance between Eu 3+ ions for energy transfer was determined to be 18 Å

  20. Synthesis and photoluminescence properties of self-assembled Eu-doped ZnO hollow microspheres

    Energy Technology Data Exchange (ETDEWEB)

    Xu, Jin [Department of Materials Science and Engineering, College of Materials, Xiamen University, Siming South Road 422, 361005 Xiamen (China); Key Laboratory for Fire Retardant Materials of Fujian Province, Xiamen University, Siming South Road 422, 361005 Xiamen (China); Wang, Nating; Wang, Weiqiang [Department of Materials Science and Engineering, College of Materials, Xiamen University, Siming South Road 422, 361005 Xiamen (China)

    2011-12-15

    ZnO hollow microspheres with a shell wall consisting of crystalline ZnO nanosheets were synthesized by using Zn{sub 5}(CO{sub 3}){sub 2}(OH){sub 6} microspheres as spherical templates. Zn{sub 5}(CO{sub 3}){sub 2}(OH){sub 6} microspheres were first fabricated by a solvothermal procedure in an ethylene glycol (EG)-water solution. ZnO microspheres with a hexagonal structure were identified by means of X-ray diffraction (XRD) and selected-area electron diffraction (SAED). On the basis of the results, a possible self-assembly growth mechanism was proposed. It reveals that the EG played an important role in determining the hollow morphologies of Zn{sub 5}(CO{sub 3}){sub 2}(OH){sub 6} structures. In addition, photoluminescence (PL) investigation of ZnO:Eu{sup 3+} suggested that a direct energy transfer occurred, which was ascribed to the energy transfer from ZnO host to Eu{sup 3+} ions. (Copyright copyright 2011 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  1. Ce and Eu-doped LiSrAlF6 scintillators for neutron detectors

    International Nuclear Information System (INIS)

    Yanagida, Takayuki; Kawaguchi, Noriaki; Fujimoto, Yutaka; Yokota, Yuui; Yamazaki, Atsushi; Watanabe, Kenichi; Kamada, Kei; Yoshikawa, Akira; Chani, Valery

    2011-01-01

    Ce 1%, Eu 1%, and Eu 2%-doped LiSrAlF 6 (LiSAF) single crystals were grown by the micro-pulling-down method for thermal neutron applications. The crystals were transparent, 2.0 mm in diameter and 20–40 mm in length. Neither visible inclusions nor cracks were observed. Their transmittance spectra were measured. The strong absorption lines were observed at 200, 240, and 300 nm for Ce:LiSAF due to Ce 3+ 4f–5d transition. In Eu:LiSAF, 200 (4f–5d) and 300 (4f–4f) nm absorption lines were detected. The samples demonstrated strong emission peaks at 300 nm (Ce:LiSAF) and 370 nm (Eu:LiSAFs) when they were irradiated with 241 Am α-rays simulating the α-particles from the 6 Li(n, α) reaction. Thermal neutron responses were examined under 252 Cf irradiation. The absolute light yield of Ce, Eu 1%, and Eu 2% crystals were 3400, 18000, and 30000 ph/n, respectively. Main components of the scintillation decay time of Ce, Eu 1%, and Eu 2%-doped LiSAFs were 63, 1293, and 1205 ns.

  2. A method for making a glass supported system, such glass supported system, and the use of a glass support therefor

    NARCIS (Netherlands)

    Unnikrishnan, S.; Jansen, Henricus V.; Berenschot, Johan W.; Fazal, I.; Louwerse, M.C.; Mogulkoc, B.; Sanders, Remco G.P.; de Boer, Meint J.; Elwenspoek, Michael Curt

    2008-01-01

    The invention relates to a method for making a glass supported micro or nano system, comprising the steps of: i) providing a glass support; ii) mounting at least one system on at least one glass support; and iii) bonding the system to the glass support, such that the system is circumferentially

  3. Glass enamel and glass-ceramic coatings for chemical apparatus

    International Nuclear Information System (INIS)

    Es'kov, A.S.; Oleinik, M.I.; Shabrova, E.A.

    1984-01-01

    Among the known anticorrosion coatings used in chemical engineering, glass enamel base coatings are distinguished by such advantages as a high degree of continuity and chemical resistance. The paper describes basic principles for the creation of acid and alkali resistant glass enamel and ceramic coatings for chemical apparatus. As the result of investgations, glass enamel coatings with increased electrical conductivity and also experimental production compositions of chemical, temperature and radiation resistant coatings for protection of chemical equipment of 12Kh18N10T stainless steel have been developed. The coatings have successfully passed testing under service conditions. A new type of coating is short-term glass enamel, which may be recommended for use in chemical machinery manufacturing and other branches of industry in oxidation-free heating and forming of stainless steels

  4. Restorative glass: reversible, discreet restoration using structural glass components

    Directory of Open Access Journals (Sweden)

    Faidra Oikonomopoulou

    2017-12-01

    Full Text Available The application of structural glass as the principal material in restoration and conservation practices is a distinguishable, yet discreet approach. The transparency of glass allows the simultaneous perception of the monument at both its original and present condition, preserving its historical and aesthetical integrity. Concurrently, the material’s unique mechanical properties enable the structural consolidation of the monument. As a proof of concept, the restoration of Lichtenberg Castle is proposed. Solid cast glass units are suggested to complete the missing parts, in respect to the existing construction technique and aesthetics of the original masonry. Aiming for a reversible system, the glass units are interlocking, ensuring the overall stability without necessitating permanent, adhesive connections. This results in an elegant and reversible intervention.

  5. GLASS COMPOSITION-TCLP RESPONSE MODEL FOR WASTE GLASSES

    International Nuclear Information System (INIS)

    Kim, Dong-Sang; Vienna, John D.

    2004-01-01

    A first-order property model for normalized Toxicity Characteristic Leaching Procedure (TCLP) release as a function of glass composition was developed using data collected from various studies. The normalized boron release is used to estimate the release of toxic elements based on the observation that the boron release represents the conservative release for those constituents of interest. The current TCLP model has two targeted application areas: (1) delisting of waste-glass product as radioactive (not mixed) waste and (2) designating the glass wastes generated from waste-glass research activities as hazardous or non-hazardous. This paper describes the data collection and model development for TCLP releases and discusses the issues related to the application of the model

  6. The ions displacement through glasses

    International Nuclear Information System (INIS)

    Sevegnani, F.X.

    1980-01-01

    A method to introduce sodium, potassium, lithium, calcium, iron and other ions in vacuum or gas light bulb by mean of a strong stationay electric field. The experiments showed that the mass deposited inside the bulbs obey Faraday's law of electrolysis, although the process of mass transfer is not that of a conventional electrolysis. A method which allows to show that hydrogen ions do not penetrate the glass structure is also described. Using radioactive tracers, it is shown that heavy ions, such PO 4 --- do not penetrate the glass structure. The vitreous state and the glass properties were studied for interpreting experimental results. (Author) [pt

  7. Recent developments in laser glasses

    International Nuclear Information System (INIS)

    Weber, M.J.

    1983-01-01

    The past decade has witnessed a proliferation of new glass-forming compositions including oxides, halides, oxyhalides, and chalcogenides. Many of these glasses are applicable to lasers and have greatly expanded the range of optical properties and spectroscopic parameters available to the laser designer. Our knowledge and understanding of many properties of interest for laser action - transparency, linear and nonlinear refractive indices, and damage threshold of the host glass and the absorption spectrum, radiative and nonradiative transition probabilities, fluorescence wavelength, stimulated emission cross section, and spectroscopic inhomogeneities of the lasing ion Nd 3 + - are reviewed

  8. Shattered glass seeking the densest matter: the color glass condensate

    CERN Multimedia

    Appell, D

    2004-01-01

    "Physicists investigating heavy-particle collisions believe they are on the track of a universal form of matter, one common to very high energy particles ranging from protons to heavy nuclei such as uranium. Some think that this matter, called a color glass condensate, may explain new nuclear properties and the process of particle formation during collisions. Experimentalists have recently reported intriguing data that suggest a color glass condensate has actually formed in past work" (1 page)

  9. Properties Of Soda/Yttria/Silica Glasses

    Science.gov (United States)

    Angel, Paul W.; Hann, Raiford E.

    1994-01-01

    Experimental study of glass-formation compositional region of soda/ yttria/silicate system and of selected physical properties of glasses within compositional region part of continuing effort to identify glasses with high coefficients of thermal expansion and high softening temperatures, for use as coatings on superalloys and as glass-to-metal seals.

  10. Structural principles in network glasses

    International Nuclear Information System (INIS)

    Boolchand, P.

    1986-01-01

    Substantial progress in decoding the structure of network glasses has taken place in the past few years. Crucial insights into the molecular structure of glasses have emerged by application of Raman bond and Moessbauer site spectroscopy. In this context, the complimentary role of each spectroscopy as a check on the interpretation of the other, is perhaps one of the more significant developments in the field. New advances in the theory of the subject have also taken place. It is thus appropriate to inquire what general principles if any, have emerged on the structure of real glasses. The author reviews some of the principal ideas on the structure of inorganic network glasses with the aid of specific examples. (Auth.)

  11. Neutron diffraction studies of glasses

    International Nuclear Information System (INIS)

    Wright, A.C.

    1987-01-01

    A survey is given of the application of neutron diffraction to structural studies of oxide and halide glasses. As with crystalline materials, neutron and X-ray diffraction are the major structural probes for glasses and other amorphous solids, particularly in respect of intermediate range order. The glasses discussed mostly have structures which are dominated by a network in which the bonding is predominantly covalent. The examples discussed demonstrate the power of the neutron diffraction technique in the investigation of the structures of inorganic glasses. The best modern diffraction experiments are capable of providing accurate data with high real space resolution, which if used correctly, are an extremely fine filter for the various structural models proposed in the literature. 42 refs

  12. High Tech Art: Chameleon Glass

    Science.gov (United States)

    1993-01-01

    Dichroic Glass is a technology wherein extremely thin films of metal are vacuum deposited on a glass surface. The coated glass shields spacecraft instruments from cosmic radiation and protects human vision from unfiltered sunlight in space. Because the coating process allows some wavelengths of light and color to reflect and others to pass through, a chameleon effect is produced. Murray Schwartz, a former aerospace engineer, has based his business KROMA on this NASA optical technology. He produces dichroic stained glass windows, mobiles and jewelry. The technique involves deposition of super thin layers of metal oxides applied one layer at a time in a specific order and thickness for the desired effect. His product line is unique and has been very successful.

  13. Inorganic glass ceramic slip rings

    Science.gov (United States)

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

    1972-01-01

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

  14. Glass-Graphite Composite Materials

    International Nuclear Information System (INIS)

    Mayzan, M.Z.H.; Lloyd, J.W.; Heath, P.G.; Stennett, M.C.; Hyatt, N.C.; Hand, R.J.

    2016-01-01

    A summary is presented of investigations into the potential of producing glass-composite materials for the immobilisation of graphite or other carbonaceous materials arising from nuclear power generation. The methods are primarily based on the production of base glasses which are subsequently sintered with powdered graphite or simulant TRISO particles. Consideration is also given to the direct preparation of glass-graphite composite materials using microwave technology. Production of dense composite wasteforms with TRISO particles was more successful than with powdered graphite, as wasteforms containing larger amounts of graphite were resistant to densification and the glasses tried did not penetrate the pores under the pressureless conditions used. Based on the results obtained it is concluded that the production of dense glassgraphite composite wasteforms will require the application of pressure. (author)

  15. Turning nuclear waste into glass

    Energy Technology Data Exchange (ETDEWEB)

    Pegg, Ian L.

    2015-02-15

    Vitrification has emerged as the treatment option of choice for the most dangerous radioactive waste. But dealing with the nuclear waste legacy of the Cold War will require state-of-the-art facilities and advanced glass formulations.

  16. Glass microspheres for medical applications

    Science.gov (United States)

    Conzone, Samuel David

    Radioactive dysprosium lithium borate glass microspheres have been developed as biodegradable radiation delivery vehicles for the radiation synovectomy treatment of rheumatoid arthritis. Once injected into a diseased joint, the microspheres deliver a potent dose of radiation to the diseased tissue, while a non-uniform chemical reaction converts the glass into an amorphous, porous, hydrated dysprosium phosphate reaction product. The non-radioactive, lithium-borate component is dissolved from the glass (up to 94% weight loss), while the radioactive 165Dy reacts with phosphate anions in the body fluids, and becomes "chemically" trapped in a solid, dysprosium phosphate reaction product that has the same size as the un-reacted glass microsphere. Ethylene diamine tetraacetate (EDTA) chelation therapy can be used to dissolve the dysprosium phosphate reaction product after the radiation delivery has subsided. The dysprosium phosphate reaction product, which formed in vivo in the joint of a Sprague-Dawley rat, was dissolved by EDTA chelation therapy in 100 Gy) of localized beta radiation to a treatment site within the body, followed by complete biodegradability. The non-uniform reaction process is a desirable characteristic for a biodegradable radiation delivery vehicle, but it is also a novel material synthesis technique that can convert a glass to a highly porous materials with widely varying chemical composition by simple, low-temperature, glass/solution reaction. The reaction product formed by nonuniform reaction occupies the same volume as the un-reacted glass, and after drying for 1 h at 300°C, has a specific surface area of ≈200 m2/g, a pore size of ≈30 nm, and a nominal crushing strength of ≈10 MPa. Finally, rhenium glass microspheres, composed of micron-sized, metallic rhenium particles dispersed within a magnesium alumino borate glass matrix were produced by sintering ReO2 powder and glass frit at 1050°C. A 50 mg injection of radioactive rhenium glass

  17. Cesium glass irradiation sources

    International Nuclear Information System (INIS)

    Plodinec, M.J.

    1982-01-01

    The precipitation process for the decontamination of soluble SRP wastes produces a material whose radioactivity is dominated by 137 Cs. Potentially, this material could be vitrified to produce irradiation sources similar to the Hanford CsCl sources. In this report, process steps necessary for the production of cesium glass irradiation sources (CGS), and the nature of the sources produced, are examined. Three options are considered in detail: direct vitrification of precipitation process waste; direct vitrification of this waste after organic destruction; and vitrification of cesium separated from the precipitation process waste. Direct vitrification is compatible with DWPF equipment, but process rates may be limited by high levels of combustible materials in the off-gas. Organic destruction would allow more rapid processing. In both cases, the source produced has a dose rate of 2 x 10 4 rads/hr at the surface. Cesium separation produces a source with a dose rate of 4 x 10 5 at the surface, which is nearer that of the Hanford sources (2 x 10 6 rads/hr). Additional processing steps would be required, as well as R and D to demonstrate that DWPF equipment is compatible with this intensely radioactive material

  18. Sustainable Innovation of Glass Design and Craft

    DEFF Research Database (Denmark)

    Sparre-Petersen, Maria

    2014-01-01

    , reduction of production and transportation of new glass is desirable (Environmental Protection Agency, 2012), and can be realized by recycling glass, that has already been manufactured, used and collected for recycling, but has ended up in landfills due to the market mechanisms that allow manufacturing...... and deposition of glass is reduced Today glass production predominantly consists of window glass, glass wool for insulation and containers such as bottles and jelly jars. Glass craft and design hold only a fraction of the market. Still there is reason to believe that generation and implementation of new...

  19. Contrasting the magnetic response between magnetic-glass and reentrant spin-glass

    OpenAIRE

    Roy, S. B.; Chattopadhyay, M. K.

    2008-01-01

    Magnetic-glass is a recently identified phenomenon in various classes of magnetic systems undergoing a first order magnetic phase transition. We shall highlight here a few experimentally determined characteristics of magnetic-glass and the relevant set of experiments, which will enable to distinguish a magnetic-glass unequivocally from the well known phenomena of spin-glass and reentrant spin-glass.

  20. Glass science tutorial: Lecture number-sign 2, Operating electric glass melters. James N. Edmonson, Lecturer

    International Nuclear Information System (INIS)

    Kruger, A.A.

    1994-10-01

    This report contains basic information on electric furnaces used for glass melting and on the properties of glass useful for the stabilization of radioactive wastes. Furnace nomenclature, furnace types, typical silicate glass composition and properties, thermal conductivity information, kinetics of the melting process, glass furnace refractory materials composition and thermal conductivity, and equations required for the operation of glass melters are included

  1. Investigations on vanadium doped glasses

    International Nuclear Information System (INIS)

    Madhusudana Rao, P.

    2013-01-01

    The glass samples studied in the present work have been prepared by melt quenching technique. They were prepared by mixing and grinding together by appropriate amounts of Li 2 O - Na 2 O - B 2 O 3 doped with V 2 O 5 in an agate motor before transferring into crucible. The mixtures were heated in an electric furnace at 1225K for 20 mm. The melt was then quenched to room temperature by pouring it on plane brass plate and pressing it with another brass plate. White and yellow coloured glasses have been obtained with good optical quality and high transparency. Finally the vitreous sample were annealed for 3 hrs at 423K to relieve residual internal stress and slowly cooled to room temperature. The polished glasses have been used for XRD, FTIR analysis and for DSC report. The DSC thermo grams for all the glasses were recorded on in the temperature range 50-550℃ with a heating rate of 10℃/min. Electron spin resonance and optical absorption of 20Li 2 O - 10 Na 2 O - (70-X)B 2 O 3 doped with XV 2 O 5 glass system are studied. ESR spectra of V 4+ ions doped in the glass exhibit peak at g =1.98. Spin Hamiltonian parameters are calculated. It was found that these parameters are dependent upon alkali ion concentration in the glass and the VO +2 ion in an octahedral coordination with a tetragonal compression. The physical parameters of all glasses were also evaluated with respect to the composition

  2. Perspective: Highly stable vapor-deposited glasses

    Science.gov (United States)

    Ediger, M. D.

    2017-12-01

    This article describes recent progress in understanding highly stable glasses prepared by physical vapor deposition and provides perspective on further research directions for the field. For a given molecule, vapor-deposited glasses can have higher density and lower enthalpy than any glass that can be prepared by the more traditional route of cooling a liquid, and such glasses also exhibit greatly enhanced kinetic stability. Because vapor-deposited glasses can approach the bottom of the amorphous part of the potential energy landscape, they provide insights into the properties expected for the "ideal glass." Connections between vapor-deposited glasses, liquid-cooled glasses, and deeply supercooled liquids are explored. The generality of stable glass formation for organic molecules is discussed along with the prospects for stable glasses of other types of materials.

  3. Production of lightweight foam glass (invited talk)

    DEFF Research Database (Denmark)

    Petersen, Rasmus Rosenlund; König, Jakob; Yue, Yuanzheng

    The foam glass production allows low cost recycling of postconsumer glass and industrial waste materials as foaming agent or as melt resource. Foam glass is commonly produced by utilising milled glass mixed with a foaming agent. The powder mixture is heat-treated to around 10^3.7 – 10^6 Pa s, which...... result in viscous sintering and subsequent foaming of the glass melt. The porous glass melt is cooled down to room temperature to freeze-in the foam structure. The resulting foam glass is applied in constructions as a light weight material to reduce load bearing capacity and as heat insulating material...... in buildings and industry. We foam panel glass from old televisions with different foaming agents. We discuss the foaming ability and the foaming mechanism of different foaming systems. We compare several studies to define a viscous window for preparing low density foam glass. However, preparing foam glass...

  4. BNFL Report Glass Formers Characterization

    Energy Technology Data Exchange (ETDEWEB)

    Schumacher, R.F.

    2000-07-27

    The objective of this task was to obtain powder property data on candidate glass former materials, sufficient to guide conceptual design and estimate the cost of glass former handling facilities as requested under Part B1 of BNFL Technical and Development Support. Twenty-nine glass forming materials were selected and obtained from vendors for the characterization of their physical properties, durability in caustic solution, and powder flow characteristics. A glass former was selected based on the characterization for each of the ten oxide classes required for Envelope A, B, and C mixtures. Three blends (A, B, and C) were prepared based on formulations provided by Vitreous State Laboratory and evaluated with the same methods employed for the glass formers. The properties obtained are presented in a series of attached Tables. It was determined that five of the ten glass formers, (kyanite, iron oxide, titania, zircon, and zinc oxide) have the potential to cause some level of solids f low problems. The problems might include arching or ratholing in the silo/hopper. In addition, all of the blends may require consideration for their handling.

  5. BNFL Report Glass Formers Characterization

    Energy Technology Data Exchange (ETDEWEB)

    Schumacher, R.F.

    2000-07-27

    The objective of this task was to obtain powder property data on candidate glass former materials, sufficient to guide conceptual design and estimate the cost of glass former handling facilities as requested under Part B1 of BNFL Technical and Development Support. Twenty-nine glass forming materials were selected and obtained from vendors for the characterization of their physical properties, durability in caustic solution, and powder flow characteristics. A glass former was selected based on the characterization for each of the ten oxide classes required for Envelope A, B, and C mixtures. Three blends (A, B, and C) were prepared based on formulations provided by Vitreous State Laboratory and evaluated with the same methods employed for the glass formers. The properties obtained are presented in a series of attached Tables. It was determined that five of the ten glass formers, (kyanite, iron oxide, titania, zircon, and zinc oxide) have the potential to cause some level of solids f low problems. In addition, all of the blends may require consideration for their handling. A number of engineering considerations and recommendations were prepared based on the experimental findings, experience, and other process considerations. Recommendations for future testing are included. In conjunction with future work, it is recommended that a professional consultant be engaged to guide and assist with testing and design input.

  6. BNFL Report Glass Formers Characterization

    International Nuclear Information System (INIS)

    Schumacher, R.F.

    2000-01-01

    The objective of this task was to obtain powder property data on candidate glass former materials, sufficient to guide conceptual design and estimate the cost of glass former handling facilities as requested under Part B1 of BNFL Technical and Development Support. Twenty-nine glass forming materials were selected and obtained from vendors for the characterization of their physical properties, durability in caustic solution, and powder flow characteristics. A glass former was selected based on the characterization for each of the ten oxide classes required for Envelope A, B, and C mixtures. Three blends (A, B, and C) were prepared based on formulations provided by Vitreous State Laboratory and evaluated with the same methods employed for the glass formers. The properties obtained are presented in a series of attached Tables. It was determined that five of the ten glass formers, (kyanite, iron oxide, titania, zircon, and zinc oxide) have the potential to cause some level of solids f low problems. In addition, all of the blends may require consideration for their handling. A number of engineering considerations and recommendations were prepared based on the experimental findings, experience, and other process considerations. Recommendations for future testing are included. In conjunction with future work, it is recommended that a professional consultant be engaged to guide and assist with testing and design input

  7. Bioactive glasses: Frontiers and challenges

    Directory of Open Access Journals (Sweden)

    Larry L. Hench

    2015-11-01

    Full Text Available Bioactive glasses were discovered in 1969 and provided for the first time an alternative to nearly inert implant materials. Bioglass formed a rapid, strong and stable bond with host tissues. This article examines the frontiers of research crossed to achieve clinical use of bioactive glasses and glass-ceramics. In the 1980’s it was discovered that bioactive glasses could be used in particulate form to stimulate osteogenesis, which thereby led to the concept of regeneration of tissues. Later, it was discovered that the dissolution ions from the glasses behaved like growth factors, providing signals to the cells. This article summarizes the frontiers of knowledge crossed during four eras of development of bioactive glasses that have led from concept of bioactivity to widespread clinical and commercial use, with emphasis on the first composition, 45S5 Bioglass®. The four eras are: a discovery; b clinical application; c tissue regeneration; and d innovation. Questions still to be answered for the fourth era are included to stimulate innovation in the field and exploration of new frontiers that can be the basis for a general theory of bioactive stimulation of regeneration of tissues and application to numerous clinical needs.

  8. BNFL Report Glass Formers Characterization

    International Nuclear Information System (INIS)

    Schumacher, R.F.

    2000-01-01

    The objective of this task was to obtain powder property data on candidate glass former materials, sufficient to guide conceptual design and estimate the cost of glass former handling facilities as requested under Part B1 of BNFL Technical and Development Support. Twenty-nine glass forming materials were selected and obtained from vendors for the characterization of their physical properties, durability in caustic solution, and powder flow characteristics. A glass former was selected based on the characterization for each of the ten oxide classes required for Envelope A, B, and C mixtures. Three blends (A, B, and C) were prepared based on formulations provided by Vitreous State Laboratory and evaluated with the same methods employed for the glass formers. The properties obtained are presented in a series of attached Tables. It was determined that five of the ten glass formers, (kyanite, iron oxide, titania, zircon, and zinc oxide) have the potential to cause some level of solids f low problems. The problems might include arching or ratholing in the silo/hopper. In addition, all of the blends may require consideration for their handling

  9. Crystallization of Yttrium and Samarium Aluminosilicate Glasses

    OpenAIRE

    Lago, Diana Carolina; Prado, Miguel Oscar

    2016-01-01

    Aluminosilicate glasses containing samarium and yttrium (SmAS and YAS glasses) exhibit high glass transition temperatures, corrosion resistance, and glass stability on heating which make them useful for technological applications. Yttrium aluminosilicate glass microspheres are currently being used for internal selective radiotherapy of liver cancer. During the preparation process, crystallization needs to be totally or partially avoided depending on the final application. Thus knowing the cry...

  10. Glass Membrane For Controlled Diffusion Of Gases

    Science.gov (United States)

    Shelby, James E.; Kenyon, Brian E.

    2001-05-15

    A glass structure for controlled permeability of gases includes a glass vessel. The glass vessel has walls and a hollow center for receiving a gas. The glass vessel contains a metal oxide dopant formed with at least one metal selected from the group consisting of transition metals and rare earth metals for controlling diffusion of the gas through the walls of the glass vessel. The vessel releases the gas through its walls upon exposure to a radiation source.

  11. High-Level Waste Glass Formulation Model Sensitivity Study 2009 Glass Formulation Model Versus 1996 Glass Formulation Model

    International Nuclear Information System (INIS)

    Belsher, J.D.; Meinert, F.L.

    2009-01-01

    This document presents the differences between two HLW glass formulation models (GFM): The 1996 GFM and 2009 GFM. A glass formulation model is a collection of glass property correlations and associated limits, as well as model validity and solubility constraints; it uses the pretreated HLW feed composition to predict the amount and composition of glass forming additives necessary to produce acceptable HLW glass. The 2009 GFM presented in this report was constructed as a nonlinear optimization calculation based on updated glass property data and solubility limits described in PNNL-18501 (2009). Key mission drivers such as the total mass of HLW glass and waste oxide loading are compared between the two glass formulation models. In addition, a sensitivity study was performed within the 2009 GFM to determine the effect of relaxing various constraints on the predicted mass of the HLW glass.

  12. Natural analogues of nuclear waste glass corrosion

    International Nuclear Information System (INIS)

    Abrajano, T.A. Jr.; Ebert, W.L.; Luo, J.S.

    1999-01-01

    This report reviews and summarizes studies performed to characterize the products and processes involved in the corrosion of natural glasses. Studies are also reviewed and evaluated on how well the corrosion of natural glasses in natural environments serves as an analogue for the corrosion of high-level radioactive waste glasses in an engineered geologic disposal system. A wide range of natural and experimental corrosion studies has been performed on three major groups of natural glasses: tektite, obsidian, and basalt. Studies of the corrosion of natural glass attempt to characterize both the nature of alteration products and the reaction kinetics. Information available on natural glass was then compared to corresponding information on the corrosion of nuclear waste glasses, specifically to resolve two key questions: (1) whether one or more natural glasses behave similarly to nuclear waste glasses in laboratory tests, and (2) how these similarities can be used to support projections of the long-term corrosion of nuclear waste glasses. The corrosion behavior of basaltic glasses was most similar to that of nuclear waste glasses, but the corrosion of tektite and obsidian glasses involves certain processes that also occur during the corrosion of nuclear waste glasses. The reactions and processes that control basalt glass dissolution are similar to those that are important in nuclear waste glass dissolution. The key reaction of the overall corrosion mechanism is network hydrolysis, which eventually breaks down the glass network structure that remains after the initial ion-exchange and diffusion processes. This review also highlights some unresolved issues related to the application of an analogue approach to predicting long-term behavior of nuclear waste glass corrosion, such as discrepancies between experimental and field-based estimates of kinetic parameters for basaltic glasses

  13. Natural analogues of nuclear waste glass corrosion.

    Energy Technology Data Exchange (ETDEWEB)

    Abrajano, T.A. Jr.; Ebert, W.L.; Luo, J.S.

    1999-01-06

    This report reviews and summarizes studies performed to characterize the products and processes involved in the corrosion of natural glasses. Studies are also reviewed and evaluated on how well the corrosion of natural glasses in natural environments serves as an analogue for the corrosion of high-level radioactive waste glasses in an engineered geologic disposal system. A wide range of natural and experimental corrosion studies has been performed on three major groups of natural glasses: tektite, obsidian, and basalt. Studies of the corrosion of natural glass attempt to characterize both the nature of alteration products and the reaction kinetics. Information available on natural glass was then compared to corresponding information on the corrosion of nuclear waste glasses, specifically to resolve two key questions: (1) whether one or more natural glasses behave similarly to nuclear waste glasses in laboratory tests, and (2) how these similarities can be used to support projections of the long-term corrosion of nuclear waste glasses. The corrosion behavior of basaltic glasses was most similar to that of nuclear waste glasses, but the corrosion of tektite and obsidian glasses involves certain processes that also occur during the corrosion of nuclear waste glasses. The reactions and processes that control basalt glass dissolution are similar to those that are important in nuclear waste glass dissolution. The key reaction of the overall corrosion mechanism is network hydrolysis, which eventually breaks down the glass network structure that remains after the initial ion-exchange and diffusion processes. This review also highlights some unresolved issues related to the application of an analogue approach to predicting long-term behavior of nuclear waste glass corrosion, such as discrepancies between experimental and field-based estimates of kinetic parameters for basaltic glasses.

  14. Chiral-glass transition and replica symmetry breaking of a three-dimensional Heisenberg spin glass

    OpenAIRE

    Hukushima, K.; Kawamura, H.

    2000-01-01

    Extensive equilibrium Monte Carlo simulations are performed for a three-dimensional Heisenberg spin glass with the nearest-neighbor Gaussian coupling to investigate its spin-glass and chiral-glass orderings. The occurrence of a finite-temperature chiral-glass transition without the conventional spin-glass order is established. Critical exponents characterizing the transition are different from those of the standard Ising spin glass. The calculated overlap distribution suggests the appearance ...

  15. Aqueous corrosion of silicate glasses. Analogy between volcanic glasses and the French nuclear waste glass R7T7

    International Nuclear Information System (INIS)

    Goldschmidt, F.

    1991-01-01

    The behaviour of borosilicate glasses upon aqueous corrosion is controlled for long periods of time (>10,000 years) by processes which are not directly accessible by means of laboratory experiments. The analogical approach consists here to compare leaching performances between the french nuclear waste glass R7T7 and natural volcanic glasses, basaltic and rhyolitic ones. The three glasses were leached in the same conditions; open system, 90 deg C, initial pH of 9.7. Basaltic and R7T7 glasses having the same kinetic of dissolution, the basaltic glass was chosen as the best analogue. (author). refs., figs., tabs

  16. Relative leach behavior of waste glasses and naturally occurring glasses

    International Nuclear Information System (INIS)

    Adams, P.B.

    1979-01-01

    Simulated nuclear waste glasses of the sodium-borosilicate type with a low waste loading and of the zinc-borosilicate type with a high waste loading have been compared with obsidians. The resuls indicate that the waste glasses would corrode in normal natural environments at a rate of about 0.1 μm per year at 30 0 C and about 5 μm per year at 90 0 C, compared with obsidians which seem to corrode at, or less than, about 0.01 μm per year at 30 0 C and less than 1 μm per year at 90 0 C. Activation energies for reactions of the two waste glasses with pure water are about 20 kcal/g-mol. 3 figures, 7 tables

  17. Database for waste glass composition and properties

    International Nuclear Information System (INIS)

    Peters, R.D.; Chapman, C.C.; Mendel, J.E.; Williams, C.G.

    1993-09-01

    A database of waste glass composition and properties, called PNL Waste Glass Database, has been developed. The source of data is published literature and files from projects funded by the US Department of Energy. The glass data have been organized into categories and corresponding data files have been prepared. These categories are glass chemical composition, thermal properties, leaching data, waste composition, glass radionuclide composition and crystallinity data. The data files are compatible with commercial database software. Glass compositions are linked to properties across the various files using a unique glass code. Programs have been written in database software language to permit searches and retrievals of data. The database provides easy access to the vast quantities of glass compositions and properties that have been studied. It will be a tool for researchers and others investigating vitrification and glass waste forms

  18. Volumetric change of simulated radioactive waste glass irradiated by electron accelerator. [Silica glass

    Energy Technology Data Exchange (ETDEWEB)

    Sato, Seichi; Furuya, Hirotaka; Inagaki, Yaohiro; Kozaka, Tetsuo; Sugisaki, Masayasu

    1987-11-01

    Density changes of simulated radioactive waste glasses, silica glass and Pyrex glass irradiated by an electron accelerator were measured by a ''sink-float'' technique. The density changes of the waste and silica glasses were less than 0.05 %, irradiated at 2.0 MeV up to the fluence of 1.7 x 10/sup 17/ ecm/sup 2/, while were remarkably smaller than that of Pyrex glass of 0.18 % shrinkage. Precision of the measurements in the density changes of the waste glass was lower than that of Pyrex glass possibly because of the inhomogeneity of the waste glass

  19. Ultrasonic relaxations in borate glasses

    International Nuclear Information System (INIS)

    D'Angelo, G.; Tripodo, G.; Carini, G.; Cosio, E.; Bartolotta, A.; Di Marco, G.

    2004-01-01

    The attenuation and velocity of ultrasonic waves of frequencies in the range from 10 to 70 MHz have been measured in M 2 O-B 2 O 3 borate glasses (M: Li or Ag) as a function of temperature between 15 and 350 K. The velocity of sound waves decreases with increasing temperature in all the glasses, the decrease as the temperature is increased is larger in glasses containing silver than in those with lithium. A broad relaxation peak characterises the attenuation behaviour of the lithium and silver borate glasses at temperatures below 100 K and is paralleled by a corresponding dispersive behaviour of the sound velocity. Above 100 K, the ultrasonic velocity shows a nearly linear behaviour regulated by the vibrational anharmonicity, which decreases with increasing content of modifier oxide and is smaller in lithium than in silver borates. These results suggest that the relaxation of structural defects and the anharmonicity of borate glasses are strongly affected by two parameters: the number of bridging bonds per network forming ion and the polarising power of network modifier ions which occupy sites in the existing interstices

  20. Yield point of metallic glass

    International Nuclear Information System (INIS)

    Shimizu, Futoshi; Ogata, Shigenobu; Li, Ju

    2006-01-01

    Shear bands form in most bulk metallic glasses (BMGs) within a narrow range of uniaxial strain ε y ≅ 2%. We propose this critical condition corresponds to embryonic shear band (ESB) propagation, not its nucleation. To propagate an ESB, the far-field shear stress τ ∞ ∼ Eε y /2 must exceed the quasi-steady-state glue traction τ glue of shear-alienated glass until the glass transition temperature is approached internally due to frictional heating, at which point ESB matures as a runaway shear crack. The incubation length scale l inc necessary for this maturation is estimated to be ∼10 2 nm for Zr-based BMGs, below which sample size-scale shear localization does not happen. In shear-alienated glass, the last resistance against localized shearing comes from extremely fast downhill dissipative dynamics of timescale comparable to atomic vibrations, allowing molecular dynamics (MD) simulations to capture this recovery process which governs τ glue . We model four metallic glasses: a binary Lennard-Jones system, two binary embedded atom potential systems and a quinternary embedded atom system. Despite vast differences in the structure and interatomic interactions, the four MD calculations give ε y predictions of 2.4%, 2.1%, 2.6% and 2.9%, respectively

  1. HLW Glass Studies: Development of Crystal-Tolerant HLW Glasses

    Energy Technology Data Exchange (ETDEWEB)

    Matyas, Josef; Huckleberry, Adam R.; Rodriguez, Carmen P.; Lang, Jesse B.; Owen, Antionette T.; Kruger, Albert A.

    2012-04-02

    In our study, a series of lab-scale crucible tests were performed on designed glasses of different compositions to further investigate and simulate the effect of Cr, Ni, Fe, Al, Li, and RuO2 on the accumulation rate of spinel crystals in the glass discharge riser of the HLW melter. The experimental data were used to expand the compositional region covered by an empirical model developed previously (Matyáš et al. 2010b), improving its predictive performance. We also investigated the mechanism for agglomeration of particles and impact of agglomerates on accumulation rate. In addition, the TL was measured as a function of temperature and composition.

  2. Exoelectron emission from magnesium borate glass ceramics

    International Nuclear Information System (INIS)

    Kawamoto, Takamichi; Yanagisawa, Hideo; Nakamichi, Hiroshi; Kikuchi, Riichi; Kawanishi, Masaharu.

    1986-01-01

    Thermally stimulated exoelectron emission (TSEE) of a magnesium borate glass ceramics was investigated for its application to dosemetric use. It has been found that the TSEE glow patterns of the magnesium borate glass ceramics as well as a Li 2 B 4 O 7 glass ceramics depend on the kind of the radiation used and that the heat resistance of the magnesium borate glass ceramics is higher than that of the Li 2 B 4 O 7 glass ceramics. Therefore, the TSEE glow patterns of the magnesium borate glass ceramics indicate a possibility to be used as the dose measurement for each kind of radiation in the mixed radiation field. (author)

  3. Studies of glasses by positron annihilation

    International Nuclear Information System (INIS)

    Brauer, G.; Boden, G.

    1981-04-01

    Investigations of silica glasses, pyrocerams and metallic glasses by positron annihilation (lifetime, Doppler broadening) are presented. The measurements on silica glasses showed, that silica glass fused from naturally occuring quartz exhibits a higher order than that one produced from SiCl 4 . Furthermore it was found that the order of silica glasses increases after heat treatment above 900 0 C. Thus the X-amorphous state of silica glasses could be characterized by positron annihilation what is impossible at present by diffraction methods. (author)

  4. Oxycarbonitride glass formation by melt solidification

    Energy Technology Data Exchange (ETDEWEB)

    Imon, M M; Risbud, S H

    1986-04-01

    Experimental results are presented from the synthesis and characterization of multianion oxycarbonitride glasses composed of MgSiAlON glass powders with SiC additions of 5, 10, or 15 wt pct. Nitrogen additions to the oxide MgO-Al2O3-SiO2 glasses increased devitrification resistance, but carbon additions to MgSiAlON glasses promote crystal nucleation. These properties are relevant to the oxycarbonitride glasses use in refractory glass-ceramic and ceramic-ceramic composite systems with good elevated temperature performance. 9 references.

  5. Heterogeneities in nuclear waste glass

    International Nuclear Information System (INIS)

    Ladirat, Ch.

    1997-01-01

    The industrial vitrification of high level radioactive wastes is a 2 stage process. During the first stage, the concentrated solution is heated in a spinning resistance oven at the temperature of 400 Celsius degrees till evaporation and calcination. The second stage begins when the dry residue falls into a melting pot that is maintained at a temperature of 1100-1150 Celsius degrees. Glass fretting is added and the glass is elaborated through the fusion of the different elements present in the melting pot. Heterogeneities in the glass may be associated to: - the presence in the solution to vitrify of insoluble elements from the dissolution of the fuel (RuO 2 , Rh, Pd), - the presence of minuscule metal scraps (Zr) that have been produced during the cutting of the fuel element, - the failures to conform to the technical specifications of the vitrification process, for instance, temperatures or flow rates when introducing the different elements in the melting pot. (A.C.)

  6. Gauge theory of glass transition

    International Nuclear Information System (INIS)

    Vasin, Mikhail

    2011-01-01

    A new analytical approach for the description of the glass transition in a frustrated system is suggested. The theory is based on the non-equilibrium dynamics technique, and takes into account the interaction of the local order field with the massive gauge field, which describes frustration-induced plastic deformation. The glass transition is regarded as a phase transition interrupted because of the premature critical slowing-down of one of the degrees of freedom caused by the frustrations. It is shown that freezing of the system appears when the correlation length and relaxation time of the gauge field diverge. The Vogel–Fulcher–Tammann relation for the transition kinetics and the critical exponent for the nonlinear susceptibility, 2.5∼ t correlation function dependence on time, and explains the boson peak appearance on this curve. In addition, the function of the glass transition temperature value with cooling rate is derived; this dependence fully conforms with known experimental data

  7. Glasses obtained from industrial wastes

    International Nuclear Information System (INIS)

    Bortoluzzi, D.; Oliveira Fillho, J.; Uggioni, E.; Bernardin, A.M.

    2009-01-01

    This paper deals with the study of the vitrification mechanism as an inertization method for industrial wastes contaminated with heavy metals. Ashes from coal (thermoelectric), wastes from mining (fluorite and feldspar) and plating residue were used to compose vitreous systems planed by mixture design. The chemical composition of the wastes was determined by XRF and the formulations were melted at 1450 deg C for 2h using 10%wt of CaCO 3 (fluxing agent). The glasses were poured into a mold and annealed (600 deg C). The characteristic temperatures were determined by thermal analysis (DTA, air, 20 deg C/min) and the mechanical behavior by Vickers microhardness. As a result, the melting temperature is strongly dependent on silica content of each glass, and the fluorite residue, being composed mainly by silica, strongly affects Tm. The microhardness of all glasses is mainly affected by the plating residue due to the high iron and zinc content of this waste. (author)

  8. X-ray luminescent glasses

    International Nuclear Information System (INIS)

    Takahashi, T.; Yamada, O.

    1981-01-01

    X-ray luminescent glasses comprising a divalent cation such as an alkaline earth metal or other divalent cations such as pb, cd, or zn, and certain rare earth metaphosphates are suitable as vitreous, x-ray phosphors or x-ray luminescent glass fibers in an x-ray intensifying screen. The glasses have the composition n(Mo X p2o5)((1-y)tb2o3 X yce2o3 X 3p2o5) wherein N is greater than zero but less than or equal to 16, M is an alkaline earth metal or other divalent cation such as pb, cd, or zn, and Y is greater than or equal to zero but less than one

  9. Phase transitions and glass transition in a hyperquenched silica–alumina glass

    DEFF Research Database (Denmark)

    Zhang, Y.F.; Zhao, D.H.; Yue, Yuanzheng

    2017-01-01

    We investigate phase transitions, glass transition, and dynamic behavior in the hyperquenched 69SiO2–31Al2O3 (mol%) glass (SA glass). Upon reheating, the SA glass exhibits a series of thermal responses. Subsequent to the sub-Tg enthalpy release, the glass undergoes a large jump in isobaric heat...... capacity (ΔCp) during glass transition, implying the fragile nature of the SA glass. The mullite starts to form before the end of glass transition, indicating that the SA glass is extremely unstable against crystallization. After the mullite formation, the remaining glass phase exhibits an increased Tg...... and a suppressed ΔCp. The formation of cristobalite at 1553 K indicates the dominance of silica in the remaining glass matrix. The cristobalite gradually re-melts as the isothermal heat-treatment temperature is raised from 1823 to 1853 K, which is well below the melting point of cristobalite, while the amount...

  10. Glass Foreign Body Hand Radiograph

    Directory of Open Access Journals (Sweden)

    Hamid Ehsani-Nia, DO

    2018-04-01

    Full Text Available History of present illness: A 27-year-old female sustained an injury to her left hand after she tripped and fell on a vase. She presented to the emergency department (ED complaining of pain over the laceration. Upon examination, patient presented with multiple small abrasions of the medial aspect of the left 5thdigit that are minimally tender. Additionally, she has one 0.5cm linear laceration of the medial aspect of the 5thmetacarpal with severe tenderness in the area and palpable underlying foreign body. Significant findings: Left hand plain radiography demonstrated a subcutaneous foreign body medial to the 5thmetacarpal that is radiopaque, trapezoidal in shape, and measures approximately 11mm x 3mm. Discussion: Laceration repairs are amongst the most common procedures in the emergency department; however, consideration for foreign body is often underdiagnosed. Imaging is performed in only about 11% of all traumatic wounds in the ED.1 Of those injuries relating to the hand that are subsequently imaged, about 15% are found to have a foreign body.2,3 Additionally, it is estimated that foreign bodies are present in 7% to 8.7% of all wounds caused by glass objects.4,5 Glass is among the most common foreign bodies in lacerations, and fortunately they are radiopaque and relatively well visualized radiographically. It has been demonstrated that 2mm glass foreign bodies have a 99% detection rate with radiography, and 1mm glass foreign bodies an 83% detection rate.6 Patient perception of foreign body has a positive predictive value of 31%, making it a poor source in influencing clinical decision-making to obtain wound radiographs.3 Clinicians should have a high suspicion for foreign body in lacerations, particularly those caused by glass, and utilize close physical examination and imaging for evaluation. Topics: Radiography, glass, foreign body, trauma

  11. Fission tracks diameters in glasses

    International Nuclear Information System (INIS)

    Garzon Ruiperez, L.; Veiguela, J.

    1974-01-01

    Standard glass microscope slides have been irradiated with fission fragments from the uranium. The etching track conditions have been the same for the series, having changed the etching time only for each specimen. For each glass, a minimum of 250 measurements of the tracks diameters have been made, the distributions of which are the bimodal type. Diameters-etching dependence with time is roughly lineal. Energy determinations have been made with the help of the diameters-energy relations. The calculated values agree very well with the know ones. (author) [es

  12. Plate shell structures of glass

    DEFF Research Database (Denmark)

    Bagger, Anne

    to their curved shape. A plate shell structure maintains a high stiffness-to-weight ratio, while facilitating the use of plane structural elements. The study focuses on using laminated glass panes for the load bearing facets. Various methods of generating a plate shell geometry are suggested. Together with Ghent......, such as facet size, imperfections, and connection characteristics. The critical load is compared to that of a similar, but smoothly curved, shell structure. Based on the investigations throughout the study, a set of guidelines for the structural design of plate shells of glass is proposed....

  13. Characteristics of radiophotoluminescent glass dosimeters

    Energy Technology Data Exchange (ETDEWEB)

    Ito, Masashi; Shiraishi, Akemi; Murakami, Hiroyuki [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment

    2001-07-01

    In Japan Atomic Energy Research Institute, a film badge is recently replaced by a new type radiophotoluminescent (RPL) glass dosimeter for external personal monitoring. Some fundamental characteristics of this dosimeter, such as dose dependence linearity, energy dependence, angular dependence, dose evaluation accuracy at mixed irradiation conditions, fading, etc., were examined at the Facility of Radiation Standard (FRS), JAERI. The results have proved that the RPL glass dosimeter has sufficient characteristics for practical use as a personal dosimeter for all of the items examined. (author)

  14. START - glass model of PWR

    International Nuclear Information System (INIS)

    Marn, J.; Ramsak, M.

    1998-01-01

    Recognizing the importance of nuclear engineering in the area of process engineering the University of Maribor, Faculty of Mechanical Engineering has invested in procuring and erecting glass model of pressurized water reactor. This paper deals with description of the model, its capabilities, and plans for its use within nuclear engineering community of Slovenia. The model, made primarily of glass, serves three purposes: educational, professional development and research. As an example, medium break loss of coolant accident is presented in the paper. Temperatures within primary and secondary side, and pressure on primary side of reactor coolant system are followed. The characteristic points are emphasized, and commented.(author)

  15. Glass Ceiling : Women in management

    OpenAIRE

    Rantala, Virve

    2010-01-01

    This study has examined the phenomenon called Glass Ceiling. It has approached the phenomenon in two different views. One is career development and another one is women in management. Main purpose for this study was to inspect women working life and career opportunities. Why women’s career developments end in a certain level? What is glass ceiling and how to break it? Paper also investigates reasons behind the effect. Prejudices and biases are the worst enemies for women’s career. How to chan...

  16. Recycling of post-consumer glass: energy savings, CO2 emission reduction, effects on glass quality and glass melting

    NARCIS (Netherlands)

    Beerkens, R.G.C.; Kers, G.; Santen, E. van

    2011-01-01

    This presentation shows the advantages of re-melting post-consumer glass, but also the potential risks of using contaminated cullet in the raw material batch of glass furnaces (e.g. container glass furnaces). As an example of potential advantages: increasing the cullet % in the batch of an efficient

  17. Glass Transition, Crystallization of Glass-Forming Melts, and Entropy

    Directory of Open Access Journals (Sweden)

    Jürn W. P. Schmelzer

    2018-02-01

    Full Text Available A critical analysis of possible (including some newly proposed definitions of the vitreous state and the glass transition is performed and an overview of kinetic criteria of vitrification is presented. On the basis of these results, recent controversial discussions on the possible values of the residual entropy of glasses are reviewed. Our conclusion is that the treatment of vitrification as a process of continuously breaking ergodicity with entropy loss and a residual entropy tending to zero in the limit of zero absolute temperature is in disagreement with the absolute majority of experimental and theoretical investigations of this process and the nature of the vitreous state. This conclusion is illustrated by model computations. In addition to the main conclusion derived from these computations, they are employed as a test for several suggestions concerning the behavior of thermodynamic coefficients in the glass transition range. Further, a brief review is given on possible ways of resolving the Kauzmann paradox and its implications with respect to the validity of the third law of thermodynamics. It is shown that neither in its primary formulations nor in its consequences does the Kauzmann paradox result in contradictions with any basic laws of nature. Such contradictions are excluded by either crystallization (not associated with a pseudospinodal as suggested by Kauzmann or a conventional (and not an ideal glass transition. Some further so far widely unexplored directions of research on the interplay between crystallization and glass transition are anticipated, in which entropy may play—beyond the topics widely discussed and reviewed here—a major role.

  18. Flight Deck I-Glasses, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — Flight Deck i-Glasses is a color, stereoscopic 3-D display mounted on consumer style eye glass frames that will enhance operator performance and multi-modal...

  19. Light scattering in glass-ceramics

    International Nuclear Information System (INIS)

    Hendy, S.C.

    2002-01-01

    Full text: Glass-ceramic materials with microstructures comprised of dispersed nanocrystallites in a residual glass matrix show promise for many new technological applications. In particular, transparent glass-ceramics offer low thermal expansion and stability, in addition to the prospect of novel non-linear optical properties that can arise from the nanocrystallites. Good transparency requires low optical scattering and low atomic absorption. Light scattering in the glass-ceramic arises primarily from the glass-crystallite interface. The attenuation due to scattering (turbidity) will depend upon the difference in refractive index of the two phases and the size and distribution of nanocrystallites in the glass. Here we consider models of glass-ceramic structure formation and look at scattering in these model structures to increase our understanding of the transparency of glass-ceramics

  20. Foaming Glass Using High Pressure Sintering

    DEFF Research Database (Denmark)

    Østergaard, Martin Bonderup; Petersen, Rasmus Rosenlund; König, Jakob

    Foam glass is a high added value product which contributes to waste recycling and energy efficiency through heat insulation. The foaming can be initiated by a chemical or physical process. Chemical foaming with aid of a foaming agent is the dominant industrial process. Physical foaming has two...... to expand. After heat-treatment foam glass can be obtained with porosities of 80–90 %. In this study we conduct physical foaming of cathode ray tube (CRT) panel glass by sintering under high pressure (5-25 MPa) using helium, nitrogen, or argon at 640 °C (~108 Pa s). Reheating a sample in a heating...... variations. One way is by saturation of glass melts with gas. The other involves sintering of powdered glass under a high gas pressure resulting in glass pellets with high pressure bubbles entrapped. Reheating the glass pellets above the glass transition temperature under ambient pressure allows the bubbles...

  1. Packaging glass with hierarchically nanostructured surface

    KAUST Repository

    He, Jr-Hau

    2017-08-03

    An optical device includes an active region and packaging glass located on top of the active region. A top surface of the packaging glass includes hierarchical nanostructures comprised of honeycombed nanowalls (HNWs) and nanorod (NR) structures extending from the HNWs.

  2. Large Area Sputter Coating on Glass

    Science.gov (United States)

    Katayama, Yoshihito

    Large glass has been used for commercial buildings, housings and vehicles for many years. Glass size for flat displays is getting larger and larger. The glass for the 8th generation is more than 5 m2 in area. Demand of the large glass is increasing not only in these markets but also in a solar cell market growing drastically. Therefore, large area coating is demanded to plus something else on glass more than ever. Sputtering and pyrolysis are the major coating methods on large glass today. Sputtering process is particularly popular because it can deposit a wide variety of materials in good coating uniformity on the glass. This paper describes typical industrial sputtering system and recent progress in sputtering technology. It also shows typical coated glass products in architectural, automotive and display fields and comments on their functions, film stacks and so on.

  3. Packaging glass with hierarchically nanostructured surface

    KAUST Repository

    He, Jr-Hau; Fu, Hui-Chun

    2017-01-01

    An optical device includes an active region and packaging glass located on top of the active region. A top surface of the packaging glass includes hierarchical nanostructures comprised of honeycombed nanowalls (HNWs) and nanorod (NR) structures

  4. Manganese activated phosphate glass for dosimetry

    International Nuclear Information System (INIS)

    Regulla, D.

    1975-01-01

    A measuring element comprises a metaphosphate glass doped with manganese as an activator. The manganese activated metaphosphate glass can detect and determine radiation doses in the range between milliroentgens and more than 10 megaroentgens. (auth)

  5. Some recent developments in spin glasses

    Indian Academy of Sciences (India)

    I give some experimental and theoretical background to spin glasses, and then discuss the ... Results of Monte Carlo simulations of the Heisenberg spin glass model in three dimensions are presented. ..... with equal probability. This has a ...

  6. Heating-induced glass-glass and glass-liquid transformations in computer simulations of water

    Science.gov (United States)

    Chiu, Janet; Starr, Francis W.; Giovambattista, Nicolas

    2014-03-01

    Water exists in at least two families of glassy states, broadly categorized as the low-density (LDA) and high-density amorphous ice (HDA). Remarkably, LDA and HDA can be reversibly interconverted via appropriate thermodynamic paths, such as isothermal compression and isobaric heating, exhibiting first-order-like phase transitions. We perform out-of-equilibrium molecular dynamics simulations of glassy water using the ST2 model to study the evolution of LDA and HDA upon isobaric heating. Depending on pressure, glass-to-glass, glass-to-crystal, glass-to-vapor, as well as glass-to-liquid transformations are found. Specifically, heating LDA results in the following transformations, with increasing heating pressures: (i) LDA-to-vapor (sublimation), (ii) LDA-to-liquid (glass transition), (iii) LDA-to-HDA-to-liquid, (iv) LDA-to-HDA-to-liquid-to-crystal, and (v) LDA-to-HDA-to-crystal. Similarly, heating HDA results in the following transformations, with decreasing heating pressures: (a) HDA-to-crystal, (b) HDA-to-liquid-to-crystal, (c) HDA-to-liquid (glass transition), (d) HDA-to-LDA-to-liquid, and (e) HDA-to-LDA-to-vapor. A more complex sequence may be possible using lower heating rates. For each of these transformations, we determine the corresponding transformation temperature as function of pressure, and provide a P-T "phase diagram" for glassy water based on isobaric heating. Our results for isobaric heating dovetail with the LDA-HDA transformations reported for ST2 glassy water based on isothermal compression/decompression processes [Chiu et al., J. Chem. Phys. 139, 184504 (2013)]. The resulting phase diagram is consistent with the liquid-liquid phase transition hypothesis. At the same time, the glass phase diagram is sensitive to sample preparation, such as heating or compression rates. Interestingly, at least for the rates explored, our results suggest that the LDA-to-liquid (HDA-to-liquid) and LDA-to-HDA (HDA-to-LDA) transformation lines on heating are related

  7. Heating-induced glass-glass and glass-liquid transformations in computer simulations of water

    International Nuclear Information System (INIS)

    Chiu, Janet; Giovambattista, Nicolas; Starr, Francis W.

    2014-01-01

    Water exists in at least two families of glassy states, broadly categorized as the low-density (LDA) and high-density amorphous ice (HDA). Remarkably, LDA and HDA can be reversibly interconverted via appropriate thermodynamic paths, such as isothermal compression and isobaric heating, exhibiting first-order-like phase transitions. We perform out-of-equilibrium molecular dynamics simulations of glassy water using the ST2 model to study the evolution of LDA and HDA upon isobaric heating. Depending on pressure, glass-to-glass, glass-to-crystal, glass-to-vapor, as well as glass-to-liquid transformations are found. Specifically, heating LDA results in the following transformations, with increasing heating pressures: (i) LDA-to-vapor (sublimation), (ii) LDA-to-liquid (glass transition), (iii) LDA-to-HDA-to-liquid, (iv) LDA-to-HDA-to-liquid-to-crystal, and (v) LDA-to-HDA-to-crystal. Similarly, heating HDA results in the following transformations, with decreasing heating pressures: (a) HDA-to-crystal, (b) HDA-to-liquid-to-crystal, (c) HDA-to-liquid (glass transition), (d) HDA-to-LDA-to-liquid, and (e) HDA-to-LDA-to-vapor. A more complex sequence may be possible using lower heating rates. For each of these transformations, we determine the corresponding transformation temperature as function of pressure, and provide a P-T “phase diagram” for glassy water based on isobaric heating. Our results for isobaric heating dovetail with the LDA-HDA transformations reported for ST2 glassy water based on isothermal compression/decompression processes [Chiu et al., J. Chem. Phys. 139, 184504 (2013)]. The resulting phase diagram is consistent with the liquid-liquid phase transition hypothesis. At the same time, the glass phase diagram is sensitive to sample preparation, such as heating or compression rates. Interestingly, at least for the rates explored, our results suggest that the LDA-to-liquid (HDA-to-liquid) and LDA-to-HDA (HDA-to-LDA) transformation lines on heating are related

  8. Heating-induced glass-glass and glass-liquid transformations in computer simulations of water

    Energy Technology Data Exchange (ETDEWEB)

    Chiu, Janet; Giovambattista, Nicolas [Department of Physics, Brooklyn College of the City University of New York, Brooklyn, New York 11210 (United States); Starr, Francis W. [Department of Physics, Wesleyan University, Middletown, Connecticut 06459 (United States)

    2014-03-21

    Water exists in at least two families of glassy states, broadly categorized as the low-density (LDA) and high-density amorphous ice (HDA). Remarkably, LDA and HDA can be reversibly interconverted via appropriate thermodynamic paths, such as isothermal compression and isobaric heating, exhibiting first-order-like phase transitions. We perform out-of-equilibrium molecular dynamics simulations of glassy water using the ST2 model to study the evolution of LDA and HDA upon isobaric heating. Depending on pressure, glass-to-glass, glass-to-crystal, glass-to-vapor, as well as glass-to-liquid transformations are found. Specifically, heating LDA results in the following transformations, with increasing heating pressures: (i) LDA-to-vapor (sublimation), (ii) LDA-to-liquid (glass transition), (iii) LDA-to-HDA-to-liquid, (iv) LDA-to-HDA-to-liquid-to-crystal, and (v) LDA-to-HDA-to-crystal. Similarly, heating HDA results in the following transformations, with decreasing heating pressures: (a) HDA-to-crystal, (b) HDA-to-liquid-to-crystal, (c) HDA-to-liquid (glass transition), (d) HDA-to-LDA-to-liquid, and (e) HDA-to-LDA-to-vapor. A more complex sequence may be possible using lower heating rates. For each of these transformations, we determine the corresponding transformation temperature as function of pressure, and provide a P-T “phase diagram” for glassy water based on isobaric heating. Our results for isobaric heating dovetail with the LDA-HDA transformations reported for ST2 glassy water based on isothermal compression/decompression processes [Chiu et al., J. Chem. Phys. 139, 184504 (2013)]. The resulting phase diagram is consistent with the liquid-liquid phase transition hypothesis. At the same time, the glass phase diagram is sensitive to sample preparation, such as heating or compression rates. Interestingly, at least for the rates explored, our results suggest that the LDA-to-liquid (HDA-to-liquid) and LDA-to-HDA (HDA-to-LDA) transformation lines on heating are related

  9. Structural relaxation in annealed hyperquenched basaltic glasses

    DEFF Research Database (Denmark)

    Guo, Xiaoju; Mauro, John C.; Potuzak, M.

    2012-01-01

    The enthalpy relaxation behavior of hyperquenched (HQ) and annealed hyperquenched (AHQ) basaltic glass is investigated through calorimetric measurements. The results reveal a common onset temperature of the glass transition for all the HQ and AHQ glasses under study, indicating that the primary...... relaxation is activated at the same temperature regardless of the initial departure from equilibrium. The analysis of secondary relaxation at different annealing temperatures provides insights into the enthalpy recovery of HQ glasses....

  10. Granular packing as model glass formers

    International Nuclear Information System (INIS)

    Wang Yujie

    2017-01-01

    Static granular packings are model hard-sphere glass formers. The nature of glass transition has remained a hotly debated issue. We review recent experimental progresses in using granular materials to study glass transitions. We focus on the growth of glass order with five-fold symmetry in granular packings and relate the findings to both geometric frustration and random first-order phase transition theories. (paper)

  11. Volcanic glasses, their origins and alteration processes

    Science.gov (United States)

    Friedman, I.; Long, W.

    1984-01-01

    Natural glass can be formed by volcanic processes, lightning (fulgarites) burning coal, and by meteorite impact. By far the most common process is volcanic - basically the glass is rapidly chilled molten rock. All natural glasses are thermodynamically unstable and tend to alter chemically or to crystallize. The rate of these processes is determined by the chemical composition of the magma. The hot and fluid basaltic melts have a structure that allows for rapid crystal growth, and seldom forms glass selvages greater than a few centimeters thick, even when the melt is rapidly cooled by extrusion in the deep sea. In contrast the cooler and very viscous rhyolitic magmas can yield bodies of glass that are tens of meters thick. These highly polymerized magmas have a high silica content - often 71-77% SiO2. Their high viscosity inhibits diffusive crystal growth. Basalt glass in sea water forms an alteration zone called palagonite whose thickness increases linearly with time. The rate of diffusion of water into rhyolitic glass, which follows the relationship - thickness = k (time) 1 2, has been determined as a function of the glass composition and temperature. Increased SiO2 increases the rate, whereas increased CaO, MgO and H2O decrease the rate. The activation energy of water diffusion varies from about 19 to 22 kcal/mol. for the glasses studied. The diffusion of alkali out of rhyolite glass occurs simultaneously with water diffusion into the glass. The rate of devitrification of rhyolitic glass is a function of the glass viscosity, which in turn is a function of water content and temperature. Although all of the aforementioned processes tend to destroy natural glasses, the slow rates of these processes, particularly for rhyolitic glass, has allowed samples of glass to persist for 60 million years. ?? 1984.

  12. Embedded adhesive connection for laminated glass plates

    DEFF Research Database (Denmark)

    Hansen, Jens Zangenberg; Poulsen, S.H.; Bagger, A.

    2012-01-01

    The structural behavior of a new connection design, the embedded adhesive connection, used for laminated glass plates is investigated. The connection consists of an aluminum plate encapsulated in-between two adjacent triple layered laminated glass plates. Fastening between glass and aluminum...... usage in a design situation. The embedded connection shows promising potential as a future fastening system for load-carrying laminated glass plates....

  13. Effect of small glass composition changes on flue gas emissions of glass furnaces

    NARCIS (Netherlands)

    Limpt, J.A.C. van; Beerkens, R.G.C.; Kersbergen, M.J. van

    2008-01-01

    Relatively small changes in glass composition might have drastic consequences on the evaporation rates of volatile glass components in glass melting furnaces. Transpiration evaporation tests have been applied to measure the impact of minor glass composition changes on the evaporation rates of

  14. Percolation and spin glass transition

    International Nuclear Information System (INIS)

    Sadiq, A.; Tahir-Kheli, R.A.; Wortis, M.; Bhatti, N.A.

    1980-10-01

    The behaviour of clusters of curved and normal plaquette particles in a bond random, +-J, Ising model is studied in finite square and triangular lattices. Computer results for the concentration of antiferromagnetic bonds when percolating clusters first appears are found to be close to those reported for the occurrence and disappearance of spin glass phases in these systems. (author)

  15. Moessbauerspectroscopy on Gold Ruby Glass

    International Nuclear Information System (INIS)

    Haslbeck, S.

    2005-01-01

    In this thesis, the chemical states of gold and the physical mechanisms of the growing process of the particles under the influence of additional ingredients like tin, lead, antimony and selenium before, during and after the colouring process are investigated by using the Moessbauer spectroscopy on 197 Au, 119 Sn and 121 Sb, optical spectroscopy and X-ray-diffraction. Gold in an unnealed, colourless state of the glasses consists of monovalent forming linear bonds to two neighbouring oxygen atoms. The Lamb-Moessbauer factor of these gold oxide bondings is observed as 0.095 at 4.2 K. The gold in it's oxide state transforms to gold particles with a diameter of 3 nm to 60 nm. The size of the gold particles is quite definable within the optical spectra and certain sizes are also discernable within the Moessbauer spectra. One component of the Moessbauer spectra is assigned to the surface layer of the gold particles. By comparing this surface component with the amount of the bulk metallic core, one can calculate the size of the gold particles. In the Moessbauer spectra of the colourless glass one also can find parts of bulk metallic gold. Investigations with X-ray diffraction show that these are gold particles with a diameter of 100 nm to 300 nm and therefore have no additional colouring effect within the visible spectrum. The Moessbauer spectra on gold of the remelt glasses are similar to those which have been measured on the initial colourless glasses

  16. Physical ageing of silicate glasses

    Energy Technology Data Exchange (ETDEWEB)

    Nemilov, S.V. [S. I. Vavilov State Optical Inst., St. Petersburg (Russian Federation)

    2003-02-01

    The presented review has been devoted to the problem of volume-determined properties relaxation of silicate glasses at room temperature. It is shown that the experimental data are described by the simple Debye exponential law or by a superposition of two exponents. Their parameters are calculated and systematized. A molecular-kinetic model is proposed for these ageing processes. It proceeds from the possibility of volume relaxation due to the cooperative β-relaxation mechanism with no change in the system's topology. The characteristic ageing times can be calculated according to equations obtained based on the viscosity data in the glass transition range. The precision of the calculations is about {+-} 15% at the time variations from a few weeks up to about 15 years. The system of calculated parameters is proposed which characterizes the completeness of ageing and its rate at any glass age. Optical and thermometric glasses have been ranked by their tendency to ageing. The scheme of future investigations predetermined by practice is defined. (orig.)

  17. Spin glasses and neural networks

    International Nuclear Information System (INIS)

    Parga, N.; Universidad Nacional de Cuyo, San Carlos de Bariloche

    1989-01-01

    The mean-field theory of spin glass models has been used as a prototype of systems with frustration and disorder. One of the most interesting related systems are models of associative memories. In these lectures we review the main concepts developed to solve the Sherrington-Kirkpatrick model and its application to neural networks. (orig.)

  18. Durable Glass For Thousands Of Years

    International Nuclear Information System (INIS)

    Jantzen, C.

    2009-01-01

    The durability of natural glasses on geological time scales and ancient glasses for thousands of years is well documented. The necessity to predict the durability of high level nuclear waste (HLW) glasses on extended time scales has led to various thermodynamic and kinetic approaches. Advances in the measurement of medium range order (MRO) in glasses has led to the understanding that the molecular structure of a glass, and thus the glass composition, controls the glass durability by establishing the distribution of ion exchange sites, hydrolysis sites, and the access of water to those sites. During the early stages of glass dissolution, a 'gel' layer resembling a membrane forms through which ions exchange between the glass and the leachant. The hydrated gel layer exhibits acid/base properties which are manifested as the pH dependence of the thickness and nature of the gel layer. The gel layer ages into clay or zeolite minerals by Ostwald ripening. Zeolite mineral assemblages (higher pH and Al 3+ rich glasses) may cause the dissolution rate to increase which is undesirable for long-term performance of glass in the environment. Thermodynamic and structural approaches to the prediction of glass durability are compared versus Ostwald ripening.

  19. Mechanical Properties of Stable Glasses Using Nanoindentation

    Science.gov (United States)

    Wolf, Sarah; Liu, Tianyi; Jiang, Yijie; Ablajan, Keyume; Zhang, Yue; Walsh, Patrick; Turner, Kevin; Fakhraai, Zahra

    Glasses with enhanced stability over ordinary, liquid quenched glasses have been formed via the process of Physical Vapor Deposition (PVD) by using a sufficiently slow deposition rate and a substrate temperature slightly below the glass transition temperature. These stable glasses have been shown to exhibit higher density, lower enthalpy, and better kinetic stability over ordinary glass, and are typically optically birefringent, due to packing and orientational anisotropy. Given these exceptional properties, it is of interest to further investigate how the properties of stable glasses compare to those of ordinary glass. In particular, the mechanical properties of stable glasses remain relatively under-investigated. While the speed of sound and elastic moduli have been shown to increase with increased stability, little is known about their hardness and fracture toughness compared to ordinary glasses. In this study, glasses of 9-(3,5-di(naphthalen-1-yl)phenyl)anthracene were deposited at varying temperatures relative to their glass transition temperature, and their mechanical properties measured by nanoindentation. Hardness and elastic modulus of the glasses were compared across substrate temperatures. After indentation, the topography of these films were studied using Atomic Force Microscopy (AFM) in order to further compare the relationship between thermodynamic and kinetic stability and mechanical failure. Z.F. and P.W. acknowledge funding from NSF(DMREF-1628407).

  20. Characterization of Fe -doped silver phosphate glasses

    Indian Academy of Sciences (India)

    ... to their several spe- cial properties such as large thermal expansion coefficients, ... increase the conductivity of these glasses is to increase the modifier or dopant ... phosphate glasses were measured by the a.c. impedance spectroscopic .... and Fe2O3-doped Ag2O–P2O5 glasses were determined from. DSC curves and ...

  1. Some recent developments in spin glasses

    Indian Academy of Sciences (India)

    I give some experimental and theoretical background to spin glasses, and then discuss the nature of the phase transition in spin glasses with vector spins. Results of Monte Carlo simulations of the Heisenberg spin glass model in three dimensions are presented. A finite-size scaling analysis of the correlation length of the ...

  2. Nickel-iron spherules from aouelloul glass

    Science.gov (United States)

    Chao, E.C.T.; Dwornik, E.J.; Merrill, C.W.

    1966-01-01

    Nickel-iron spherules, ranging from less than 0.2 to 50 microns in diameter and containing 1.7 to 9.0 percent Ni by weight, occur in glass associated with the Aouelloul crater. They occur in discrete bands of siliceous glass enriched in dissolved iron. Their discovery is significant tangible evidence that both crater and glass originated from terrestrial impact.

  3. Jagged Edges of the Glass Ceiling

    Science.gov (United States)

    Robinson, Victoria L.

    2004-01-01

    Although many aspiring young women might believe the glass ceiling was shattered a decade ago, they still need to understand how that glass ceiling impacted an older generation of women in educational leadership. They also must be aware that some segments of the glass ceiling might still exist. This article provides a historical overview of the…

  4. Review of glass ceramic waste forms

    International Nuclear Information System (INIS)

    Rusin, J.M.

    1981-01-01

    Glass ceramics are being considered for the immobilization of nuclear wastes to obtain a waste form with improved properties relative to glasses. Improved impact resistance, decreased thermal expansion, and increased leach resistance are possible. In addition to improved properties, the spontaneous devitrification exhibited in some waste-containing glasses can be avoided by the controlled crystallization after melting in the glass-ceramic process. The majority of the glass-ceramic development for nuclear wastes has been conducted at the Hahn-Meitner Institute (HMI) in Germany. Two of their products, a celsian-based (BaAl 3 Si 2 O 8 ) and a fresnoite-based (Ba 2 TiSi 2 O 8 ) glass ceramic, have been studied at Pacific Northwest Laboratory (PNL). A basalt-based glass ceramic primarily containing diopsidic augite (CaMgSi 2 O 6 ) has been developed at PNL. This glass ceramic is of interest since it would be in near equilibrium with a basalt repository. Studies at the Power Reactor and Nuclear Fuel Development Corporation (PNC) in Japan have favored a glass-ceramic product based upon diopside (CaMgSi 2 O 6 ). Compositions, processing conditions, and product characterization of typical commercial and nuclear waste glass ceramics are discussed. In general, glass-ceramic waste forms can offer improved strength and decreased thermal expansion. Due to typcially large residual glass phases of up to 50%, there may be little improvement in leach resistance

  5. Aging in chalcohalide glasses: Origin and consequences

    DEFF Research Database (Denmark)

    Jensen, Martin; Smedskjær, Morten Mattrup; Wang, W.

    2012-01-01

    the elemental concentration depth profiles in the surface layer of the glasses by using secondary neutral mass spectroscopy. The results show that anionic diffusion processes occur in the glasses during aging. The aging process leads to a decrease in microhardness of the studied glasses, which is attributed...

  6. DURABLE GLASS FOR THOUSANDS OF YEARS

    Energy Technology Data Exchange (ETDEWEB)

    Jantzen, C.

    2009-12-04

    The durability of natural glasses on geological time scales and ancient glasses for thousands of years is well documented. The necessity to predict the durability of high level nuclear waste (HLW) glasses on extended time scales has led to various thermodynamic and kinetic approaches. Advances in the measurement of medium range order (MRO) in glasses has led to the understanding that the molecular structure of a glass, and thus the glass composition, controls the glass durability by establishing the distribution of ion exchange sites, hydrolysis sites, and the access of water to those sites. During the early stages of glass dissolution, a 'gel' layer resembling a membrane forms through which ions exchange between the glass and the leachant. The hydrated gel layer exhibits acid/base properties which are manifested as the pH dependence of the thickness and nature of the gel layer. The gel layer ages into clay or zeolite minerals by Ostwald ripening. Zeolite mineral assemblages (higher pH and Al{sup 3+} rich glasses) may cause the dissolution rate to increase which is undesirable for long-term performance of glass in the environment. Thermodynamic and structural approaches to the prediction of glass durability are compared versus Ostwald ripening.

  7. Grinding Glass Disks On A Belt Sander

    Science.gov (United States)

    Lyons, James J., III

    1995-01-01

    Small machine attached to table-top belt sander makes possible to use belt sander to grind glass disk quickly to specified diameter within tolerance of about plus or minus 0.002 in. Intended to be used in place of production-shop glass grinder. Held on driveshaft by vacuum, glass disk rotated while periphery ground by continuous sanding belt.

  8. Effects of composition on waste glass properties

    International Nuclear Information System (INIS)

    Mellinger, G.B.; Chick, L.A.

    1979-01-01

    The electrical conductivity, viscosity, chemical durability, devitrification, and crystallinity of a defense waste glass were measured. Each oxide component in the glass was varied to determine its effect on these properties. A generic study is being developed which will determine the effects of 26 oxides on the above and additional properties of a wide field of possible waste glasses. 5 figures, 2 tables

  9. Spin-glass transition in disordered terbium

    International Nuclear Information System (INIS)

    Hauser, J.J.

    1985-01-01

    While crystalline Tb is a helix antiferromagnet with a Neel temperature of 229 K which becomes ferromagnetic at 222 K, disordered Tb exhibits a spin-glass transition. The spin-glass freezing temperature ranges from 183 to 53 K, the lowest temperatures corresponding to the greatest degree of atomic disorder. These experiments constitute the first evidence for an elemental spin-glass. (author)

  10. Superconducting state parameters of ternary metallic glasses

    Indian Academy of Sciences (India)

    Administrator

    to binary metallic glasses. They are of interest since third element can modify the physical properties of binary metallic glasses and can also be used as a probe to study the host. ..... conducting nature in the present case. When we. Figure 6. Variation of transition temperature (TC) with valance (Z) of ternary metallic glasses.

  11. The corrosion behavior of DWPF glasses

    International Nuclear Information System (INIS)

    Ebert, W.L.; Bates, J.K.

    1995-01-01

    The authors analyzed the corroded surfaces of reference glasses developed for the Defense Waste Processing Facility (DWPF) to characterize their corrosion behavior. The corrosion mechanism of nuclear waste glasses must be known in order to provide source terms describing radionuclide release for performance assessment calculations. Different DWPF reference glasses were corroded under conditions that highlighted various aspects of the corrosion process and led to different extents of corrosion. The glasses corroded by similar mechanisms, and a phenomenological description of their corrosion behavior is presented here. The initial leaching of soluble glass components results in the formation of an amorphous gel layer on the glass surface. The gel layer is a transient phase that transforms into a layer of clay crystallites, which equilibrates with the solution as corrosion continues. The clay layer does not act as a barrier to either water penetration or glass dissolution, which continues beneath it, and may eventually separate from the glass. Solubility limits for glass components may be established by the eventual precipitation of secondary phases; thus, corrosion of the glass becomes controlled by the chemical equilibrium between the solution and the assemblage of secondary phases. In effect, the solution is an intermediate phase through which the glass transforms to an energetically more favorable assemblage of phases. Implications regarding the prediction of long-term glass corrosion behavior are discussed

  12. Friction behavior of glass and metals in contact with glass in various environments

    Science.gov (United States)

    Buckley, D. H.

    1973-01-01

    Sliding friction experiments have been conducted for heat-resistant glass and metals in contact with glass. These experiments were conducted in various environments including vacuum, moist air, dry air, octane, and stearic acid in hexadecane. Glass exhibited a higher friction force in moist air than it did in vacuum when in sliding contact with itself. The metals, aluminum, iron, and gold, all exhibited the same friction coefficient when sliding on glass in vacuum as glass sliding on glass. Gold-to-glass contacts were extremely sensitive to the environment despite the relative chemical inertness of gold.

  13. Spherical 2+p spin-glass model: An exactly solvable model for glass to spin-glass transition

    International Nuclear Information System (INIS)

    Crisanti, A.; Leuzzi, L.

    2004-01-01

    We present the full phase diagram of the spherical 2+p spin-glass model with p≥4. The main outcome is the presence of a phase with both properties of full replica symmetry breaking phases of discrete models, e.g., the Sherrington-Kirkpatrick model, and those of one replica symmetry breaking. This phase has a finite complexity which leads to different dynamic and static properties. The phase diagram is rich enough to allow the study of different kinds of glass to spin glass and spin glass to spin glass phase transitions

  14. Analysis of early medieval glass beads - Glass in the transition period

    Energy Technology Data Exchange (ETDEWEB)

    Smit, Ziga, E-mail: ziga.smit@ijs.si [Faculty of Mathematics and Physics, University of Ljubljana, Jadranska 19, SI-1000 Ljubljana (Slovenia); Jozef Stefan Institute, Jamova 39, P.O.B. 3000, SI-1001 Ljubljana (Slovenia); Knific, Timotej [National Museum of Slovenia, Presernova 20, SI-1000 Ljubljana (Slovenia); Jezersek, David [Jozef Stefan Institute, Jamova 39, P.O.B. 3000, SI-1001 Ljubljana (Slovenia); Istenic, Janka [National Museum of Slovenia, Presernova 20, SI-1000 Ljubljana (Slovenia)

    2012-05-01

    Glass beads from graves excavated in Slovenia and dated archaeologically to the 7th-10th century AD were analysed by the combined PIXE-PIGE method. The results indicate two groups of glass; natron glass made in the Roman tradition and glass made with alkalis from the ash of halophytic plants, which gradually replaced natron glass after c. 800 AD. The alkalis used in the second group of glass seem to be in close relation to a variant of the Venetian white glass that appeared several centuries later. The origin of this glass may be traced to glass production in Mesopotamia and around the Aral Sea. All the mosaic beads with eye decoration, as well as most of the drawn-segmented and drawn-cut beads analysed, are of plant-ash glass, which confirms their supposed oriental origin.

  15. A simple method for tuning the glass transition process in inorganic phosphate glasses

    OpenAIRE

    Fulchiron, Ren?; Belyamani, Imane; Otaigbe, Joshua U.; Bounor-Legar?, V?ronique

    2015-01-01

    The physical modification of glass transition temperature (Tg ) and properties of materials via blending is a common practice in industry and academia and has a large economic advantage. In this context, simple production of hitherto unattainable new inorganic glass blends from already existing glass compositions via blending raises much hope with the potential to provide new glasses with new and improved properties, that cannot be achieved with classical glass synthesis, for a plethora of ap...

  16. Effect of Gamma Irradiation on Some Properties of Bismuth Silicate Glasses and Their Glass Derivatives

    International Nuclear Information System (INIS)

    Abo Hussein, E.M.K.

    2014-01-01

    Glasses containing bismuth oxide have attracted considerable attention, although it is non-conventional glass forming oxide, but it has wide applications. In this work, it is aimed to prove that bismuth silicate glass can act as a good shielding material for γ- rays. For this purpose glass containing 20% bismuth oxide and 80% SiO_2 was prepared using melting-annealing technique. Also effects of adding some alkali heavy metal oxides to this glass such as PbO, BaO or SrO were also studied. The formed glasses were also heat treated at 450 degree C for 4 hours to give the corresponding heat treated glasses. Electron Paramagnetic Resonance (EPR) measurements show that the prepared glasses and heat treated glasses have very good stability when exposed to γ- irradiation, which encourage the assumption of using these glasses as gamma ray shielding materials. Many properties have been investigated, such as density to understand the structural properties, also mechanical properties were verified by measuring microhardness, while the chemical resistance was identified by testing their durability in both acidic and basic solutions. The EPR results were supported by measuring electrical conductivity of the glass and heat treated glass samples at different temperatures ranging from 298 to 553 K, which proved that these glasses have very low conductivity even at high temperature. The formed phases of heat treated glass or glass ceramic samples were demonstrated by means of X-ray diffraction (XRD). Also studying the structure of glasses and heat treated glasses before and after irradiation was investigated by the Infrared transmitting spectra. Calculations of optical band gap energies were demonstrated for some selected glasses and heat treated glasses from the data of UV optical absorption spectra to support the probability of using these bismuth silicate glasses for gamma radiation shielding processing.

  17. Glass Durability Modeling, Activated Complex Theory (ACT)

    International Nuclear Information System (INIS)

    CAROL, JANTZEN

    2005-01-01

    The most important requirement for high-level waste glass acceptance for disposal in a geological repository is the chemical durability, expressed as a glass dissolution rate. During the early stages of glass dissolution in near static conditions that represent a repository disposal environment, a gel layer resembling a membrane forms on the glass surface through which ions exchange between the glass and the leachant. The hydrated gel layer exhibits acid/base properties which are manifested as the pH dependence of the thickness and nature of the gel layer. The gel layer has been found to age into either clay mineral assemblages or zeolite mineral assemblages. The formation of one phase preferentially over the other has been experimentally related to changes in the pH of the leachant and related to the relative amounts of Al +3 and Fe +3 in a glass. The formation of clay mineral assemblages on the leached glass surface layers ,lower pH and Fe +3 rich glasses, causes the dissolution rate to slow to a long-term steady state rate. The formation of zeolite mineral assemblages ,higher pH and Al +3 rich glasses, on leached glass surface layers causes the dissolution rate to increase and return to the initial high forward rate. The return to the forward dissolution rate is undesirable for long-term performance of glass in a disposal environment. An investigation into the role of glass stoichiometry, in terms of the quasi-crystalline mineral species in a glass, has shown that the chemistry and structure in the parent glass appear to control the activated surface complexes that form in the leached layers, and these mineral complexes ,some Fe +3 rich and some Al +3 rich, play a role in whether or not clays or zeolites are the dominant species formed on the leached glass surface. The chemistry and structure, in terms of Q distributions of the parent glass, are well represented by the atomic ratios of the glass forming components. Thus, glass dissolution modeling using simple

  18. Strong-Superstrong Transition in Glass Transition of Metallic Glass

    International Nuclear Information System (INIS)

    Dan, Wang; Hong-Yan, Peng; Xiao-Yu, Xu; Bao-Ling, Chen; Chun-Lei, Wu; Min-Hua, Sun

    2010-01-01

    Dynamic fragility of bulk metallic glass (BMG) of Zr 64 Cu 16 Ni 10 Al 10 alloy is studied by three-point beam bending methods. The fragility parameter mfor Zr 64 Cu 16 Ni 10 Al 10 BMG is calculated to be 24.5 at high temperature, which means that the liquid is a 'strong' liquid, while to be 13.4 at low temperature which means that the liquid is a 'super-strong' liquid. The dynamical behavior of Zr 64 Cu 16 Ni 10 Al 10 BMG in the supercooled region undergoes a strong to super-strong transition. To our knowledge, it is the first time that a strong-to-superstrong transition is found in the metallic glass. Using small angle x-ray scattering experiments, we find that this transition is assumed to be related to a phase separation process in supercooled liquid. (condensed matter: structure, mechanical and thermal properties)

  19. Inelastic neutron scattering from glass formers

    International Nuclear Information System (INIS)

    Buchenau, U.

    1997-01-01

    Neutron spectra below and above the glass transition temperature show a pronounced difference between strong and fragile glass formers in Angell's fragility scheme. The strong anharmonic increase of the inelastic scattering with increasing temperature in fragile substances is absent in the strongest glass former SiO 2 . That difference is reflected in the temperature dependence of Brillouin sound velocities above the glass transition. Coherent inelastic neutron scattering data indicate a mixture of sound waves and local modes at the low frequency boson peak. A relation between the fragility and the temperature dependence of the transverse hypersound velocity at the glass temperature is derived. (author)

  20. A new glass option for parenteral packaging.

    Science.gov (United States)

    Schaut, Robert A; Peanasky, John S; DeMartino, Steven E; Schiefelbein, Susan L

    2014-01-01

    Glass is the ideal material for parenteral packaging because of its chemical durability, hermeticity, strength, cleanliness, and transparency. Alkali borosilicate glasses have been used successfully for a long time, but they do have some issues relating to breakage, delamination, and variation in hydrolytic performance. In this paper, alkali aluminosilicate glasses are introduced as a possible alternative to alkali borosilicate glasses. An example alkali aluminosilicate glass is shown to meet the compendial requirements, and to have similar thermal, optical, and mechanical attributes as the current alkali borosilicate glasses. In addition, the alkali aluminosilicate performed as well or better than the current alkali borosilicates in extractables tests and stability studies, which suggests that it would be suitable for use with the studied liquid product formulation. The physical, mechanical, and optical properties of glass make it an ideal material for packaging injectable drugs and biologics. Alkali borosilicate glasses have been used successfully for a long time for these applications, but there are some issues. In this paper, alkali aluminosilicate glasses are introduced as a possible alternative to alkali borosilicate glasses. An example alkali aluminosilicate glass is shown to meet the requirements for packaging injectable drugs and biologics, and to be suitable for use with a particular liquid drug. © PDA, Inc. 2014.

  1. Identifying glass compositions in fly ash

    Directory of Open Access Journals (Sweden)

    Katherine eAughenbaugh

    2016-01-01

    Full Text Available In this study, four Class F fly ashes were studied with a scanning electron microscope; the glassy phases were identified and their compositions quantified using point compositional analysis with k-means clustering and multispectral image analysis. The results showed that while the bulk oxide contents of the fly ashes were different, the four fly ashes had somewhat similar glassy phase compositions. Aluminosilicate glasses (AS, calcium aluminosilicate glasses (CAS, a mixed glass, and, in one case, a high iron glass were identified in the fly ashes. Quartz and iron crystalline phases were identified in each fly ash as well. The compositions of the three main glasses identified, AS, CAS, and mixed glass, were relatively similar in each ash. The amounts of each glass were varied by fly ash, with the highest calcium fly ash containing the most of calcium-containing glass. Some of the glasses were identified as intermixed in individual particles, particularly the calcium-containing glasses. Finally, the smallest particles in the fly ashes, with the most surface area available to react in alkaline solution, such as when mixed with portland cement or in alkali-activated fly ash, were not different in composition than the large particles, with each of the glasses represented. The method used in the study may be applied to a fly ash of interest for use as a cementing material in order to understand its potential for reactivity.

  2. Bioactive Glasses in Dentistry: A Review

    Directory of Open Access Journals (Sweden)

    Abbasi Z

    2015-03-01

    Full Text Available Bioactive glasses are silicate-based and can form a strong chemical bond with the tissues. These biomaterials are highly biocompatible and can form a hydroxyapatite layer when implanted in the body or soaked in the simulated body fluid. Due to several disadvantages, conventional glass processing method including melting of glass components, is replaced by sol-gel method with a large number of benefits such as low processing temperature, higher purity and homogeneity and therefore better control of bioactivity. Bioactive glasses have a wide range of applications, particularly in dentistry. These glasses can be used as particulates or monolithic shapes and porous or dense constructs in different applications such as remineralization or hypersensitivity treatment. Some properties of bioactive glasses such as antibacterial properties can be promoted by adding different elements into the glass. Bioactive glasses can also be used to modify different biocompatible materials that need to be bioactive. This study reviews the significant developments of bioactive glasses in clinical application, especially dentistry. Furthermore, we will discuss the field of bioactive glasses from beginning to the current developments, which includes processing methods, applications, and properties of these glasses.

  3. Evaluation of Behaviours of Laminated Glass

    Science.gov (United States)

    Sable, L.; Japins, G.; Kalnins, K.

    2015-11-01

    Visual appearance of building facades and other load bearing structures, which now are part of modern architecture, is the reason why it is important to investigate in more detail the reliability of laminated glass for civil structures. Laminated glass in particular has become one of the trendy materials, for example Apple© stores have both load carrying capacity and transparent appearance. Glass has high mechanical strength and relatively medium density, however, the risk of sudden brittle failure like concrete or other ceramics determine relatively high conservatism in design practice of glass structures. This should be changed as consumer requirements evolve calling for a safe and reliable design methodology and corresponding building standards. A design methodology for glass and glass laminates should be urgently developed and included as a chapter in Eurocode. This paper presents initial experimental investigation of behaviour of simple glass sheets and laminated glass samples in 4-point bending test. The aim of the current research is to investigate laminated glass characteristic values and to verify the obtained experimental results with finite element method for glass and EVA material in line with future European Structural Design of Glass Components code.

  4. Control of radioactive waste-glass melters

    International Nuclear Information System (INIS)

    Bickford, D.F.; Smith, P.K.; Hrma, P.; Bowan, B.W.

    1987-01-01

    Radioactive waste-glass melters require physical control limits and redox control of glass to assure continuous operation, and maximize production rates. Typical waste-glass melter operating conditions, and waste-glass chemical reaction paths are discussed. Glass composition, batching and melter temperature control are used to avoid the information of phases which are disruptive to melting or reduce melter life. The necessity and probable limitations of control for electric melters with complex waste feed compositions are discussed. Preliminary control limits, their bases, and alternative control methods are described for use in the Defense Waste Processing Facility (DWPF) at the US Department of Energy's Savannah River Plant (SRP), and at the West Valley Demonstration Project (WVDP). Slurries of simulated high level radioactive waste and ground glass frit or glass formers have been isothermally reacted and analyzed to identify the sequence of the major chemical reactions in waste vitrification, and their effect on waste-glass production rates. Relatively high melting rates of waste batches containing mixtures of reducing agents (formic acid, sucrose) and nitrates are attributable to exothermic reactions which occur at critical stages in the vitrification process. The effect of foaming on waste glass production rates is analyzed, and limits defined for existing waste-glass melters, based upon measurable thermophysical properties. Through balancing the high nitrate wastes of the WVDP with reducing agents, the high glass melting rates and sustained melting without foaming required for successful WVDP operations have been demonstrated. 65 refs., 4 figs., 15 tabs

  5. Durability of Silicate Glasses: An Historical Approach

    International Nuclear Information System (INIS)

    Farges, Francois; Etcheverry, Marie-Pierre; Haddi, Amine; Trocellier, Patrick; Curti, Enzo; Brown, Gordon E. Jr.

    2007-01-01

    We present a short review of current theories of glass weathering, including glass dissolution, and hydrolysis of nuclear waste glasses, and leaching of historical glasses from an XAFS perspective. The results of various laboratory leaching experiments at different timescales (30 days to 12 years) are compared with results for historical glasses that were weathered by atmospheric gases and soil waters over 500 to 3000 years. Good agreement is found between laboratory experiments and slowly leached historical glasses, with a strong enrichment of metals at the water/gel interface. Depending on the nature of the transition elements originally dissolved in the melt, increasing elemental distributions are expected to increase with time for a given glass durability context

  6. Durability of Silicate Glasses: An Historical Approach

    Energy Technology Data Exchange (ETDEWEB)

    Farges, Francois; /Museum Natl. Hist. Natur. /Stanford U., Geo. Environ. Sci.; Etcheverry, Marie-Pierre; /Marne la Vallee U.; Haddi, Amine; /Marne la Valle U.; Trocellier,; /Saclay; Curti, Enzo; /PSI, Villigen; Brown, Gordon E., Jr.; /SLAC, SSRL

    2007-01-02

    We present a short review of current theories of glass weathering, including glass dissolution, and hydrolysis of nuclear waste glasses, and leaching of historical glasses from an XAFS perspective. The results of various laboratory leaching experiments at different timescales (30 days to 12 years) are compared with results for historical glasses that were weathered by atmospheric gases and soil waters over 500 to 3000 years. Good agreement is found between laboratory experiments and slowly leached historical glasses, with a strong enrichment of metals at the water/gel interface. Depending on the nature of the transition elements originally dissolved in the melt, increasing elemental distributions are expected to increase with time for a given glass durability context.

  7. Characterization of Savannah River Plant waste glass

    International Nuclear Information System (INIS)

    Plodinec, M.J.

    1985-01-01

    The objective of the glass characterization programs at the Savannah River Laboratory (SRL) is to ensure that glass containing Savannah River Plant high-level waste can be permanently stored in a federal repository, in an environmentally acceptable manner. To accomplish this objective, SRL is carrying out several experimental programs, including: fundamental studies of the reactions between waste glass and water, particularly repository groundwater; experiments in which candidate repository environments are simulated as accurately as possible; burial tests of simulated waste glass in candidate repository geologies; large-scale tests of glass durability; and determination of the effects of process conditions on glass quality. In this paper, the strategy and current status of each of these programs is discussed. The results indicate that waste packages containing SRP waste glass will satisfy emerging regulatory criteria

  8. Phase separation in an ionomer glass

    DEFF Research Database (Denmark)

    Pedersen, Malene Thostrup; Tian, K.V.; Dobó-Nagy, C.

    2015-01-01

    The G338 ionomer glass is a fluoro-alumino-silicate system, which is used as the powder component of glass ionomer cements (GICs) in dental applications. However, despite progress in understanding the nature of this glass, chemical identity of its separated amorphous phases has not yet been...... amorphous phases in G388 are Ca/Na-Al-Si-O, Ca-Al-F and Ca-P-O-F phases, respectively. However, the exact chemical compositions of the three phases still require further exploration. The results of this work are important for understanding the impact of phase separation within ionomer glasses on the setting...... conclusively determined. In this work, we identify these phases by performing differential scanning calorimetry (DSC) and X-ray diffraction (XRD) analyses on both the as-received glass and heat-treated samples. We detected three glass transitions in the as-received G338 glass during DSC upscaning, implying...

  9. Glasses, ceramics, and composites from lunar materials

    Science.gov (United States)

    Beall, George H.

    1992-01-01

    A variety of useful silicate materials can be synthesized from lunar rocks and soils. The simplest to manufacture are glasses and glass-ceramics. Glass fibers can be drawn from a variety of basaltic glasses. Glass articles formed from titania-rich basalts are capable of fine-grained internal crystallization, with resulting strength and abrasion resistance allowing their wide application in construction. Specialty glass-ceramics and fiber-reinforced composites would rely on chemical separation of magnesium silicates and aluminosilicates as well as oxides titania and alumina. Polycrystalline enstatite with induced lamellar twinning has high fracture toughness, while cordierite glass-ceramics combine excellent thermal shock resistance with high flexural strengths. If sapphire or rutile whiskers can be made, composites of even better mechanical properties are envisioned.

  10. Controlling Mackey-Glass chaos

    Science.gov (United States)

    Kiss, Gábor; Röst, Gergely

    2017-11-01

    The Mackey-Glass equation is the representative example of delay induced chaotic behavior. Here, we propose various control mechanisms so that otherwise erratic solutions are forced to converge to the positive equilibrium or to a periodic orbit oscillating around that equilibrium. We take advantage of some recent results of the delay differential literature, when a sufficiently large domain of the phase space has been shown to be attractive and invariant, where the system is governed by monotone delayed feedback and chaos is not possible due to some Poincaré-Bendixson type results. We systematically investigate what control mechanisms are suitable to drive the system into such a situation and prove that constant perturbation, proportional feedback control, Pyragas control, and state dependent delay control can all be efficient to control Mackey-Glass chaos with properly chosen control parameters.

  11. Controlling Mackey-Glass chaos.

    Science.gov (United States)

    Kiss, Gábor; Röst, Gergely

    2017-11-01

    The Mackey-Glass equation is the representative example of delay induced chaotic behavior. Here, we propose various control mechanisms so that otherwise erratic solutions are forced to converge to the positive equilibrium or to a periodic orbit oscillating around that equilibrium. We take advantage of some recent results of the delay differential literature, when a sufficiently large domain of the phase space has been shown to be attractive and invariant, where the system is governed by monotone delayed feedback and chaos is not possible due to some Poincaré-Bendixson type results. We systematically investigate what control mechanisms are suitable to drive the system into such a situation and prove that constant perturbation, proportional feedback control, Pyragas control, and state dependent delay control can all be efficient to control Mackey-Glass chaos with properly chosen control parameters.

  12. Formulation of heat absorbing glasses

    Directory of Open Access Journals (Sweden)

    Álvarez-Casariego, Pedro

    1996-06-01

    Full Text Available In the thermal exchanges between buildings and environment, glazing is an element of major importance, for it largely influences the so-called Solar Heat Gain and Thermal Losses. These parameters can be modified by applying different type of coatings onto glass surface or by adding colorant compounds during glass melting. The latter is a cheaper way to control the Solar Heat Gain. The knowledge of the laws governing the interaction between colorant compounds and solar radiation, allows us to define glass formulations achieving specific aesthetic requirements and solar energy absorption. In this paper two examples of application of the modelling of glass colorants spectral absorptance are presented. First is addressed to obtaining a glass with high luminous transmittance and low solar energy transmittance, and the other one to obtaining a glass with neutral colour appearance and minimized solar energy transmittance. Calculation formulas are defined together with photometric properties so-obtained. These type of glasses are particularly suitable to be used as building and automotive glazing, for they retain the mechanical characteristics and possibilities of transformation of standard glass.

    En los intercambios de energía entre un edificio y el medio exterior, el vidrio es el elemento de mayor importancia, por su influencia en la Ganancia de Calor Solar y en las Pérdidas Térmicas. Estos parámetros pueden ser modificados mediante el depósito de capas sobre el vidrio o mediante la adición de compuestos absorbentes de la radiación solar. Esta última vía es la más económica para controlar la Ganancia de Calor Solar. El conocimiento de las leyes que gobiernan la interacción de los diversos colorantes con la radiación solar, permite definir formulaciones de vidrios con características especificas de tipo estético y de absorción energética. En este trabajo se presentan dos ejemplos de aplicación de esta modelización de las

  13. Development of a glass GEM

    International Nuclear Information System (INIS)

    Takahashi, Hiroyuki; Mitsuya, Yuki; Fujiwara, Takeshi; Fushie, Takashi

    2013-01-01

    Gas electron multipliers (GEMs) apply the concept of gas amplification inside many tiny holes, realizing robust and high-gain proportional counters. However, the polyimide substrate of GEMs prevents them from being used in sealed detector applications. We have fabricated and tested glass GEMs (G-GEMs) with substrates made of photosensitive glass material from the Hoya Corporation. We fabricated G-GEMs with several different hole diameters and thicknesses and successfully operated test G-GEMs with a 100×100 mm 2 effective area. The uniformity of our G-GEMs was good, and the energy resolution for 5.9 keV X-rays was 18.8% under uniform irradiation of the entire effective area. A gas gain by the G-GEMs of up to 6700 was confirmed with a gas mixture of Ar (70%)+CH 4 (30%). X-ray imaging using the charge division readout method was demonstrated

  14. Lid heater for glass melter

    International Nuclear Information System (INIS)

    Phillips, T.D.

    1993-01-01

    A glass melter having a lid electrode for heating the glass melt radiantly. The electrode comprises a series of INCONEL 690 tubes running above the melt across the melter interior and through the melter walls and having nickel cores inside the tubes beginning where the tubes leave the melter interior and nickel connectors to connect the tubes electrically in series. An applied voltage causes the tubes to generate heat of electrical resistance for melting frit injected onto the melt. The cores limit heat generated as the current passes through the walls of the melter. Nickel bus connection to the electrical power supply minimizes heat transfer away from the melter that would occur if standard copper or water-cooled copper connections were used between the supply and the INCONEL 690 heating tubes. 3 figures

  15. A damage-tolerant glass.

    Science.gov (United States)

    Demetriou, Marios D; Launey, Maximilien E; Garrett, Glenn; Schramm, Joseph P; Hofmann, Douglas C; Johnson, William L; Ritchie, Robert O

    2011-02-01

    Owing to a lack of microstructure, glassy materials are inherently strong but brittle, and often demonstrate extreme sensitivity to flaws. Accordingly, their macroscopic failure is often not initiated by plastic yielding, and almost always terminated by brittle fracture. Unlike conventional brittle glasses, metallic glasses are generally capable of limited plastic yielding by shear-band sliding in the presence of a flaw, and thus exhibit toughness-strength relationships that lie between those of brittle ceramics and marginally tough metals. Here, a bulk glassy palladium alloy is introduced, demonstrating an unusual capacity for shielding an opening crack accommodated by an extensive shear-band sliding process, which promotes a fracture toughness comparable to those of the toughest materials known. This result demonstrates that the combination of toughness and strength (that is, damage tolerance) accessible to amorphous materials extends beyond the benchmark ranges established by the toughest and strongest materials known, thereby pushing the envelope of damage tolerance accessible to a structural metal.

  16. Glass ionomer cement: literature review

    OpenAIRE

    Sérgio Spezzia

    2017-01-01

    Introduction: In the dental area preventive actions occur in an attempt to avoid the installation of caries, a disease that has an increased prevalence in the population and which is a Public Health problem. Some resources are used for such, such as: performing early diagnosis and the option for conservative treatments of minimal intervention. The glass ionomer cement (CIV), coming from its beneficial characteristics that meet current trends, is closely related to the precepts of Preventive a...

  17. Basic Research on Oxynitride Glasses.

    Science.gov (United States)

    1982-07-01

    AG0 (1900 K) = -136.321 kcal (3) Si() + 1/202 (g) + SiO(g) AG (1900 K) = -60.237 kcal The reactions can be combined to yield the overall reaction (4...glass were continu- ously exposed to 95"C distilled water for 350 h in a Soxhlet apparatus. The sample weight losses after that time were 0.111Z

  18. Metallizing of machinable glass ceramic

    International Nuclear Information System (INIS)

    Seigal, P.K.

    1976-02-01

    A satisfactory technique has been developed for metallizing Corning (Code 9658) machinable glass ceramic for brazing. Analyses of several bonding materials suitable for metallizing were made using microprobe analysis, optical metallography, and tensile strength tests. The effect of different cleaning techniques on the microstructure and the effect of various firing temperatures on the bonding interface were also investigated. A nickel paste, used for thick-film application, has been applied to obtain braze joints with strength in excess of 2000 psi

  19. Chemical durability of silicoborate glasses

    International Nuclear Information System (INIS)

    Nieto, M.I.; Rodriguez, M.A.; Rubio, J.; Fernandez, A.; Oteo, J.L.

    1987-01-01

    A general view of the durability in silicoborate glasses is presented with more emphasis on the etching factors (chemical composition, lattice structure, pH...) the techniques used for this study and the experimental results. Likewise, the research presently developed in this area at the Instituto de Ceramica y Vidrio, CSIC, is related to the applications. Future research in this field is also mentioned. (author) 15 figs

  20. Taylor impact of glass rods

    International Nuclear Information System (INIS)

    Willmott, G.R.; Radford, D.D.

    2005-01-01

    The deformation and fracture behavior of soda-lime and borosilicate glass rods was examined during classic and symmetric Taylor impact experiments for impact pressures to 4 and 10 GPa, respectively. High-speed photography and piezoresistive gauges were used to measure the failure front velocities in both glasses, and for impact pressures below ∼2 GPa the failure front velocity increases rapidly with increasing pressure. As the pressure was increased above ∼3 GPa, the failure front velocities asymptotically approached maximum values between the longitudinal and shear wave velocities of each material; at ∼4 GPa, the average failure front velocities were 4.7±0.5 and 4.6±0.5 mm μs -1 for the soda-lime and borosilicate specimens, respectively. The observed mechanism of failure in these experiments involved continuous pressure-dependent nucleation and growth of microcracks behind the incident wave. As the impact pressure was increased, there was a decrease in the time to failure. The density of cracks within the failed region was material dependent, with the more open-structured borosilicate glass showing a larger fracture density

  1. Numerical study of the glass-glass transition in short-ranged attractive colloids

    International Nuclear Information System (INIS)

    Zaccarelli, Emanuela; Sciortino, Francesco; Tartaglia, Piero

    2004-01-01

    We report extensive numerical simulations in the glass region for a simple model of short-ranged attractive colloids, the square well model. We investigate the behaviour of the density autocorrelation function and of the static structure factor in the region of temperatures and packing fractions where a glass-glass transition is expected according to theoretical predictions. We strengthen our observations by studying both waiting time and history dependence of the numerical results. We provide evidence supporting the possibility that activated bond-breaking processes destabilize the attractive glass, preventing the full observation of a sharp glass-glass kinetic transition

  2. Spectroscopic study of biologically active glasses

    Science.gov (United States)

    Szumera, M.; Wacławska, I.; Mozgawa, W.; Sitarz, M.

    2005-06-01

    It is known that the chemical activity phenomenon is characteristic for some inorganic glasses and they are able to participate in biological processes of living organisms (plants, animals and human bodies). An example here is the selective removal of silicate-phosphate glass components under the influence of biological solutions, which has been applied in designing glasses acting as ecological fertilizers of controlled release rate of the nutrients for plants. The structure of model silicate-phosphate glasses containing the different amounts of the glass network formers, i.e. Ca 2+ and Mg 2+, as a binding components were studied. These elements besides other are indispensable of the normal growth of plants. In order to establish the function and position occupied by the particular components in the glass structure, the glasses were examined by FTIR spectroscopy (with spectra decomposition) and XRD methods. It has been found that the increasing amount of MgO in the structure of silicate-phosphate glasses causes the formation of domains the structure of which changes systematically from a structure of the cristobalite type to a structure corresponding to forsterite type. Whilst the increasing content of CaO in the structure of silicate-phosphate glasses causes the formation of domains the structure of which changes from a structure typical for cristobalite through one similar to the structure of calcium orthophosphate, to a structure corresponding to calcium silicates. The changing character of domains structure is the reason of different chemical activity of glasses.

  3. Edge-Strengthening of Structural Glass with Protective Coatings

    OpenAIRE

    Lindqvist Maria; Louter Christian; Lebet Jean-Paul

    2012-01-01

    In modern buildings, glass is increasingly used as a load-carrying material in structural components, such as glass beams. For glass beams especially the edge strength of glass is important. However, the strength of glass is not a material constant but depends on various parameters, which makes glass, amongst other things, a challenging building material. One of the parameters influencing glass strength is the combination of humidity and stress, which may cause stress corrosion. The aim of th...

  4. A review of glass-ionomers: From conventional glass-ionomer to bioactive glass-ionomer

    Directory of Open Access Journals (Sweden)

    Maryam Khoroushi

    2013-01-01

    Full Text Available Materials used in the body, especially the materials used in various oral cavity regions should be stable and passive without any interactions with the body tissues or fluids. Dental amalgam, composite resins and dental cements are the materials of choice with such properties. The first attempts to produce active materials, which could interact with the human body tissues and fluids were prompted by the concept that fluoride-releasing materials exert useful effects in the body. The concept of using the "smart" materials in dentistry has attracted a lot of attention in recent years. Conventional glass-ionomer (GI cements have a large number of applications in dentistry. They are biocompatible with the dental pulp to some extent. GI is predominantly used as cements in dentistry; however, they have some disadvantages, the most important of which is lack of adequate strength and toughness. In an attempt to improve the mechanical properties of the conventional GI, resin-modified glass-ionomers have been marketed, with hydrophilic monomers, such as hydroxyethyl methacrylated (HEMA. Some recent studies have evaluated GI with bioactive glass in its structure to validate the claims that such a combination will improve tooth bioactivity, regeneration capacity and restoration. There is ever-increasing interest in the application of bioactive materials in the dental field in an attempt to remineralize affected dentin. The aim of this review article is to evaluate these materials and their characteristics and applications.

  5. Borosilicate glass for gamma irradiation fields

    Science.gov (United States)

    Baydogan, N.; Tugrul, A. B.

    2012-11-01

    Four different types of silicate glass specimens were irradiated with gamma radiation using a Co-60 radioisotope. Glass specimens, with four different chemical compositions, were exposed to neutron and mixed neutron/gamma doses in the central thimble and tangential beam tube of the nuclear research reactor. Optical variations were determined in accordance with standardisation concept. Changes in the direct solar absorbance (αe) of borosilicate glass were examined using the increase in gamma absorbed dose, and results were compared with the changes in the direct solar absorbance of the three different type silicate glass specimens. Solar absorption decreased due to decrease of penetration with absorbed dose. αe of borosilicate increased considerably when compared with other glass types. Changes in optical density were evaluated as an approach to create dose estimation. Mixed/thermal neutron irradiation on glass caused to increse αe.

  6. In situ study of glasses decomposition layer

    International Nuclear Information System (INIS)

    Zarembowitch-Deruelle, O.

    1997-01-01

    The aim of this work is to understand the involved mechanisms during the decomposition of glasses by water and the consequences on the morphology of the decomposition layer, in particular in the case of a nuclear glass: the R 7 T 7 . The chemical composition of this glass being very complicated, it is difficult to know the influence of the different elements on the decomposition kinetics and on the resulting morphology because several atoms have a same behaviour. Glasses with simplified composition (only 5 elements) have then been synthesized. The morphological and structural characteristics of these glasses have been given. They have then been decomposed by water. The leaching curves do not reflect the decomposition kinetics but the solubility of the different elements at every moment. The three steps of the leaching are: 1) de-alkalinization 2) lattice rearrangement 3) heavy elements solubilization. Two decomposition layer types have also been revealed according to the glass heavy elements rate. (O.M.)

  7. A curious relationship between Potts glass models

    Science.gov (United States)

    Yamaguchi, Chiaki

    2015-08-01

    A Potts glass model proposed by Nishimori and Stephen [H. Nishimori, M.J. Stephen, Phys. Rev. B 27, 5644 (1983)] is analyzed by means of the replica mean field theory. This model is a discrete model, has a gauge symmetry, and is called the Potts gauge glass model. By comparing the present results with the results of the conventional Potts glass model, we find the coincidences and differences between the models. We find a coincidence that the property for the Potts glass phase in this model is coincident with that in the conventional model at the mean field level. We find a difference that, unlike in the case of the conventional p-state Potts glass model, this system for large p does not become ferromagnetic at low temperature under a concentration of ferromagnetic interaction. The present results support the act of numerically investigating the present model for study of the Potts glass phase in finite dimensions.

  8. Mixed mobile ion effect in fluorozincate glasses

    International Nuclear Information System (INIS)

    Ghosh, S; Ghosh, A

    2005-01-01

    The mixed mobile ion effect has been investigated for the first time in zinc fluoride glasses where in addition to alkali cations fluorine anions also participate in the diffusion process, unlike mixed alkali oxide glasses. The minimum in the conductivity, conductivity relaxation frequency, crossover frequency and decoupling index indicates the existence of the mixed mobile ion effect in these fluoride glasses. It has been observed that the non-exponential parameter and the frequency exponent are independent of temperature. It has been established that alkali ions and fluorine anions exhibit lower dimensionality of the conduction pathways in mixed alkali zinc fluoride glasses than that in the single alkali lithium based zinc fluoride glasses while they are migrating. From the scaling of the conductivity spectra, it has been established that the relaxation dynamics in mixed alkali zinc fluoride glasses is independent of temperature and composition

  9. An Economic Theory of Glass Ceiling

    OpenAIRE

    Paul A. Grout; In-Uck Park; Silvia Sonderegger

    2009-01-01

    In the 'glass ceiling' debate there appear to be two strongly held and opposing interpretations of the evidence, one suggesting it is really the result of gender differences and the other that there is discrimination by gender. This paper provides an economic theory of the glass ceiling and one of the main insights of our analysis is that in some real sense these two interpretations are not in conflict with each other. The glass ceiling emerges as an equilibrium phenomenon when firms compete ...

  10. Cooling Rates of Lunar Volcanic Glass Beads

    Science.gov (United States)

    Hui, Hejiu; Hess, Kai-Uwe; Zhang, Youxue; Peslier, Anne; Lange, Rebecca; Dingwell, Donald; Neal, Clive

    2016-01-01

    It is widely accepted that the Apollo 15 green and Apollo 17 orange glass beads are of volcanic origin. The diffusion profiles of volatiles in these glass beads are believed to be due to degassing during eruption (Saal et al., 2008). The degree of degassing depends on the initial temperature and cooling rate. Therefore, the estimations of volatiles in parental magmas of lunar pyroclastic deposits depend on melt cooling rates. Furthermore, lunar glass beads may have cooled in volcanic environments on the moon. Therefore, the cooling rates may be used to assess the atmospheric condition in an early moon, when volcanic activities were common. The cooling rates of glasses can be inferred from direct heat capacity measurements on the glasses themselves (Wilding et al., 1995, 1996a,b). This method does not require knowledge of glass cooling environments and has been applied to calculate the cooling rates of natural silicate glasses formed in different terrestrial environments. We have carried out heat capacity measurements on hand-picked lunar glass beads using a Netzsch DSC 404C Pegasus differential scanning calorimeter at University of Munich. Our preliminary results suggest that the cooling rate of Apollo 17 orange glass beads may be 12 K/min, based on the correlation between temperature of the heat capacity curve peak in the glass transition range and glass cooling rate. The results imply that the parental magmas of lunar pyroclastic deposits may have contained more water initially than the early estimations (Saal et al., 2008), which used higher cooling rates, 60-180 K/min in the modeling. Furthermore, lunar volcanic glass beads could have been cooled in a hot gaseous medium released from volcanic eruptions, not during free flight. Therefore, our results may shed light on atmospheric condition in an early moon.

  11. Immobilization of radioactive waste in glass matrices

    International Nuclear Information System (INIS)

    Wicks, G.G.

    1978-01-01

    A promising process for long-term management of high-level radioactive waste is to immobilize the waste in a borosilicate glass matrix. Among the most important criteria characterizing the integrity of the large-scale glass-waste forms are that they possess good chemical stability (including low leachability), thermal stability, mechanical integrity, and high radiation stability. Fulfillment of these criteria ensures the maximum margin of safety of glass-waste products, following solidification, handling, transportation, and long-term storage

  12. Glass Transition Temperature- and Specific Volume- Composition Models for Tellurite Glasses

    Energy Technology Data Exchange (ETDEWEB)

    Riley, Brian J. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Vienna, John D. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States)

    2017-09-01

    This report provides models for predicting composition-properties for tellurite glasses, namely specific gravity and glass transition temperature. Included are the partial specific coefficients for each model, the component validity ranges, and model fit parameters.

  13. Predicting the glass transition temperature of bioactive glasses from their molecular chemical composition.

    Science.gov (United States)

    Hill, Robert G; Brauer, Delia S

    2011-10-01

    A recently published paper (M.D. O'Donnell, Acta Biomaterialia 7 (2011) 2264-2269) suggests that it is possible to correlate the glass transition temperature (T(g)) of bioactive glasses with their molar composition, based on iterative least-squares fitting of published T(g) data. However, we show that the glass structure is an important parameter in determining T(g). Phase separation, local structural effects and components (intermediate oxides) which can switch their structural role in the glass network need to be taken into consideration, as they are likely to influence the glass transition temperature of bioactive glasses. Although the model suggested by O'Donnell works reasonably well for glasses within the composition range presented, it is oversimplified and fails for glasses outside certain compositional boundaries. Copyright © 2011 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

  14. Glass Property Data and Models for Estimating High-Level Waste Glass Volume

    Energy Technology Data Exchange (ETDEWEB)

    Vienna, John D.; Fluegel, Alexander; Kim, Dong-Sang; Hrma, Pavel R.

    2009-10-05

    This report describes recent efforts to develop glass property models that can be used to help estimate the volume of high-level waste (HLW) glass that will result from vitrification of Hanford tank waste. The compositions of acceptable and processable HLW glasses need to be optimized to minimize the waste-form volume and, hence, to save cost. A database of properties and associated compositions for simulated waste glasses was collected for developing property-composition models. This database, although not comprehensive, represents a large fraction of data on waste-glass compositions and properties that were available at the time of this report. Glass property-composition models were fit to subsets of the database for several key glass properties. These models apply to a significantly broader composition space than those previously publised. These models should be considered for interim use in calculating properties of Hanford waste glasses.

  15. High insulation foam glass material from waste cathode ray tube panel glass

    DEFF Research Database (Denmark)

    König, Jakob; Petersen, Rasmus Rosenlund; Yue, Yuanzheng

    . In general CRT consists of two types of glasses: barium/strontium containing glass (panel glass) and lead containing glass (funnel and panel glass). In this work we present the possibility to produce high performance insulation material from the recycled lead-free glass. We studied the influence of foaming...... between 750 and 850°C. We investigated the influence of milling time, particle size, foaming and oxidizing agent concentrations, temperature and time on the foaming process, foam density, foam porosity and homogeneity. Only moderate foaming was observed in carbon containing samples, while the addition...... of the oxidizing agent greatly improved the foaming quality. The results showed that the amount of oxygen available from the glass is not sufficient to combust all of the added carbon, therefore, additional oxygen was supplied via manganese reduction. In general, a minimum in the foam glass density was observed...

  16. Can painted glass felt or glass fibre cloth be used as vapour barrier?

    DEFF Research Database (Denmark)

    El-Khattam, Amira; Andersen, Mie Them; Hansen, Kurt Kielsgaard

    2014-01-01

    In most Nordic homes the interior surfaces of walls and ceilings have some kind of surface treatment for aesthetical reasons. The treatments can for example be glass felt or glass fibre cloth which are painted afterwards. To evaluate the hygrothermal performance of walls and ceilings...... treatments. The surface treatments were glass felt or glass fibre cloth with different types of paints or just paint. The paint types were acrylic paint and silicate paint. The results show that the paint type has high influence on the water vapour resistance while the underlay i.e. glass felt or glass fibre...... acrylic paint on glass felt or glass fibre cloth cannot be used instead of a vapour barrier....

  17. Iron phosphate glass containing simulated fast reactor waste: Characterization and comparison with pristine iron phosphate glass

    International Nuclear Information System (INIS)

    Joseph, Kitheri; Asuvathraman, R.; Venkata Krishnan, R.; Ravindran, T.R.; Govindaraj, R.; Govindan Kutty, K.V.; Vasudeva Rao, P.R.

    2014-01-01

    Detailed characterization was carried out on an iron phosphate glass waste form containing 20 wt.% of a simulated nuclear waste. High temperature viscosity measurement was carried out by the rotating spindle method. The Fe 3+ /Fe ratio and structure of this waste loaded iron phosphate glass was investigated using Mössbauer and Raman spectroscopy respectively. Specific heat measurement was carried out in the temperature range of 300–700 K using differential scanning calorimeter. Isoconversional kinetic analysis was employed to understand the crystallization behavior of the waste loaded iron phosphate glass. The glass forming ability and glass stability of the waste loaded glass were also evaluated. All the measured properties of the waste loaded glass were compared with the characteristics of pristine iron phosphate glass

  18. Glass Property Data and Models for Estimating High-Level Waste Glass Volume

    International Nuclear Information System (INIS)

    Vienna, John D.; Fluegel, Alexander; Kim, Dong-Sang; Hrma, Pavel R.

    2009-01-01

    This report describes recent efforts to develop glass property models that can be used to help estimate the volume of high-level waste (HLW) glass that will result from vitrification of Hanford tank waste. The compositions of acceptable and processable HLW glasses need to be optimized to minimize the waste-form volume and, hence, to save cost. A database of properties and associated compositions for simulated waste glasses was collected for developing property-composition models. This database, although not comprehensive, represents a large fraction of data on waste-glass compositions and properties that were available at the time of this report. Glass property-composition models were fit to subsets of the database for several key glass properties. These models apply to a significantly broader composition space than those previously publised. These models should be considered for interim use in calculating properties of Hanford waste glasses.

  19. The influence of glass composition on crystalline phase stability in glass-ceramic wasteforms

    International Nuclear Information System (INIS)

    Maddrell, Ewan; Thornber, Stephanie; Hyatt, Neil C.

    2015-01-01

    Highlights: • Crystalline phase formation shown to depend on glass matrix composition. • Zirconolite forms as the sole crystalline phase only for most aluminous glasses. • Thermodynamics indicate that low silica activity glasses stabilise zirconolite. - Abstract: Zirconolite glass-ceramic wasteforms were prepared using a suite of Na 2 O–Al 2 O 3 –B 2 O 3 –SiO 2 glass matrices with variable Al:B ratios. Zirconolite was the dominant crystalline phase only for the most alumina rich glass compositions. As the Al:B ratio decreased zirconolite was replaced by sphene, zircon and rutile. Thermodynamic data were used to calculate a silica activity in the glass melt below which zirconolite is the favoured crystalline phase. The concept of the crystalline reference state of glass melts is then utilised to provide a physical basis for why silica activity varies with the Al:B ratio

  20. Float glass innovation in the flat glass industry

    CERN Document Server

    Uusitalo, Olavi

    2014-01-01

    A thorough industry analysis is of utmost importance for a study on the impact of technological changes on industry structure. This book evaluates the consequences of a vaguely chosen level of an industry analysis. Too broad a definition of the industry may disaggregate sub-industries, processing industries and international aspects. This is illustrated by revisiting an industry study upon which the dominant design model was based. Readers will see and understand the consequences of too broadly defined industries together with quantitative research approach can have. The book argues that the nature of the industry should define the level of the analysis. This is done by revisiting the flat glass industry study, on which Anderson and Tushman’s (1990) dominant design model is partly based. In their study Anderson and Tushman defined the flat glass industry based on four-digit SIC codes. It is argued that this definition was too broad and it disaggregated important sub-industries, processing industries and int...

  1. Dipolar ferromagnets and glasses (invited)

    International Nuclear Information System (INIS)

    Rosenbaum, T.F.; Wu, W.; Ellman, B.; Yang, J.; Aeppli, G.; Reich, D.H.

    1991-01-01

    What is the ground state and what are the dynamics of 10 23 randomly distributed Ising spins? We have attempted to answer these questions through magnetic susceptibility, calorimetric, and neutron scattering studies of the randomly diluted dipolar-coupled Ising magnet LiHo x Y 1-x F 4 . The material is ferromagnetic for dipole concentrations at least as low as x=0.46, with a Curie temperature obeying mean-field scaling relative to that of pure LiHoF 4 . In the dilute spin limit, an x=0.045 crystal shows very unusual glassy properties characterized by decreasing barriers to relaxation as T→0. Its properties are consistent with a single low degeneracy ground state with a large gap for excitations. A slightly more concentrated x=0.167 sample, however, supports a complex ground state with no appreciable gap, in accordance with prevailing theories of spin glasses. The underlying causes of such disparate behavior are discussed in terms of random clusters as probed by neutron studies of the x=0.167 sample. In addition to tracing the evolution of the glassy and ferromagnetic states with dipole concentration, we investigate the effects of a transverse magnetic field on the Ising spin glass, LiHo 0.167 Y 0.833 F 4 . The transverse field mixes the eigenfunctions of the ground-state Ising doublet with the otherwise inaccessible excited-state levels. We observe a rapid decrease in the characteristic relaxation times, large changes in the spectral form of the relaxation, and a depression of the spin-glass transition temperature with the addition of quantum fluctuations

  2. Radiation damages on superionic conducting glasses

    International Nuclear Information System (INIS)

    Awano, T.; Handa, K.; Matsuyama, T.

    2000-01-01

    We measured ESR spectra of color centers on AgI-AgPO 3 , AgI-Ag 2 O-B 2 O 3 , AgI-Ag 2 MoO 4 , AgI-Ag 2 WO 4 , (CH 3 ) 4 NI-(C 2 H 5 ) 4 NI-AgI (TMAI-TEAI-AgI) and its derivatives of superionic conducting glasses. In organic-inorganic mixed glasses, organic ion radicals were observed. They were not affected by ionic conductivity. On the contrary, Ag 2+ , Ag 0 and aggregated Ag 0 were observed in inorganic glasses. These color centers in inorganic glasses were affected by ionic conductivity. (author)

  3. SON68 glass alteration enhanced by magnetite

    Energy Technology Data Exchange (ETDEWEB)

    Godon, Nicole; Gin, Stephane; Rebiscoul, Diane; Frugier, Pierre [CEA, DEN-Marcoule, F30207, Bagnols-sur-Ceze (France)

    2013-07-01

    This paper reports experimental and modeling results of SON68 glass / magnetite interactions while in contact with synthetic groundwater from a clay environment. It is shown that magnetite enhances glass alteration, first by the sorption of Si released from the glass onto magnetite surfaces, then by a second process that could be the precipitation of an iron silicate mineral or the transformation of magnetite into a more reactive phase like hematite or goethite. This study globally suggests a detrimental effect of magnetite on the long-term durability of nuclear glass in geological disposal conditions. (authors)

  4. Energy conservation in the EC glass industry

    Energy Technology Data Exchange (ETDEWEB)

    Waal, H. de [TNO Institute of Applied Physics, Delft (Netherlands)

    1994-12-31

    The data presented in this survey are based mainly on a recent study, performed by the Energy Technology Support Unit ETSU. Harwell Laboratory, United Kingdom, in the context of the EC-Thermie programme. Also, use has been made of a paper `Glass Manufacture, energy and CO{sub 2}-emissions`, presented by G.J. Copley of the British Glass Manufacturers Confederation, Sheffield, United Kingdom, presented at the Thermie Seminar in Wiesbaden, 1992. A third source of information has been the data collected by the CPIV, the European Glass Manufacturers Federation on the present and future economic situation of the EC Glass Industry. (orig.)

  5. Compliant Glass Seals for SOFC Stacks

    Energy Technology Data Exchange (ETDEWEB)

    Chou, Yeong -Shyung [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Choi, Jung-Pyung [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Xu, Wei [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Stephens, Elizabeth V. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Koeppel, Brian J. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Stevenson, Jeffry W. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Lara-Curzio, Edgar [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)

    2014-04-30

    This report summarizes results from experimental and modeling studies performed by participants in the Solid-State Energy Conversion Alliance (SECA) Core Technology Program, which indicate that compliant glass-based seals offer a number of potential advantages over conventional seals based on de-vitrifying glasses, including reduced stresses during stack operation and thermal cycling, and the ability to heal micro-damage induced during thermal cycling. The properties and composition of glasses developed and/or investigated in these studies are reported, along with results from long-term (up to 5,800h) evaluations of seals based on a compliant glass containing ceramic particles or ceramic fibers.

  6. Hardness of basaltic glass-ceramics

    DEFF Research Database (Denmark)

    Jensen, Martin; Smedskjær, Morten Mattrup; Estrup, Maja

    2009-01-01

    The dependence of the hardness of basaltic glass-ceramics on their degree of crystallisation has been explored by means of differential scanning calorimetry, optical microscopy, x-ray diffraction, and Vickers indentation. Different degrees of crystallisation in the basaltic glasses were achieved...... by varying the temperature of heat treatment. The predominant crystalline phase in the glass was identified as augite. It was found that the hardness of the glass phase decreased slightly with an increase in the degree of crystallisation, while that of the augite phase drastically decreased....

  7. Transverse Ising spin-glass model

    International Nuclear Information System (INIS)

    Santos, Raimundo R. dos; Santos, R.M.Z. dos.

    1984-01-01

    The zero temperature behavior of the Transverse Ising spin-glass (+-J 0 ) model is discussed. The d-dimensional quantum model is shown to be equivalent to a classical (d + 1)- dimensional Ising spin-glass with correlated disorder. An exact Renormalization Group treatment of the one-dimensional quantum model indicates the existence of a spin-glass phase. The Migdal-Kadanoff approximation is used to obtain the phase diagram of the quantum spin-glass in two-dimensions. (Author) [pt

  8. Systems approach to nuclear waste glass development

    International Nuclear Information System (INIS)

    Jantzen, C.M.

    1986-01-01

    Development of a host solid for the immobilization of nuclear waste has focused on various vitreous wasteforms. The systems approach requires that parameters affecting product performance and processing be considered simultaneously. Application of the systems approach indicates that borosilicate glasses are, overall, the most suitable glasses for the immobilization of nuclear waste. Phosphate glasses are highly durable; but the glass melts are highly corrosive and the glasses have poor thermal stability and low solubility for many waste components. High-silica glasses have good chemical durability, thermal stability, and mechanical stability, but the associated high melting temperatures increase volatilization of hazardous species in the waste. Borosilicate glasses are chemically durable and are stable both thermally and mechanically. The borosilicate melts are generally less corrosive than commercial glasses, and the melt temperature miimizes excessive volatility of hazardous species. Optimization of borosilicate waste glass formulations has led to their acceptance as the reference nuclear wasteform in the United States, United Kingdom, Belgium, Germany, France, Sweden, Switzerland, and Japan

  9. Mechanical properties of nuclear waste glasses

    International Nuclear Information System (INIS)

    Connelly, A.J.; Hand, R.J.; Bingham, P.A.; Hyatt, N.C.

    2011-01-01

    The mechanical properties of nuclear waste glasses are important as they will determine the degree of cracking that may occur either on cooling or following a handling accident. Recent interest in the vitrification of intermediate level radioactive waste (ILW) as well as high level radioactive waste (HLW) has led to the development of new waste glass compositions that have not previously been characterised. Therefore the mechanical properties, including Young's modulus, Poisson's ratio, hardness, indentation fracture toughness and brittleness of a series of glasses designed to safely incorporate wet ILW have been investigated. The results are presented and compared with the equivalent properties of an inactive simulant of the current UK HLW glass and other nuclear waste glasses from the literature. The higher density glasses tend to have slightly lower hardness and indentation fracture toughness values and slightly higher brittleness values, however, it is shown that the variations in mechanical properties between these different glasses are limited, are well within the range of published values for nuclear waste glasses, and that the surveyed data for all radioactive waste glasses fall within relatively narrow range.

  10. Radiopaque strontium fluoroapatite glass-ceramics

    Directory of Open Access Journals (Sweden)

    Wolfram eHöland

    2015-10-01

    Full Text Available The controlled precipitation of strontium fluoroapatite crystals, was studied in four base glass compositions derived from the SiO2 – Al2O3 – Y2O3 – SrO – Na2O – K2O/Rb2O/Cs2O – P2O5 – F system. The crystal phase formation of these glasses and the main properties of the glass-ceramics, such as thermal and optical properties and radiopacity were compared with a fifth, a reference glass-ceramic. The reference glass-ceramic was characterized as Ca-fluoroapatite glass-ceramic. The four strontium fluoroapatite glass-ceramics showed the following crystal phases: a Sr5(PO43F – leucite, KAlSi2O6 , b Sr5(PO43F – leucite, KAlSi2O6, and nano-sized NaSrPO4 c Sr5(PO43F – pollucite, CsAlSiO4 , and nano-sized NaSrPO4, d Sr5(PO43F – Rb-leucite, RbAlSi2O6, and nano-sized NaSrPO4.The proof of crystal phase formation was possible by X-ray diffraction (XRD. The microstructures, which were studied using scanning electron microscopy (SEM demonstrated a uniform distribution of the crystals in the glass matrix. The Sr-fluoroapatites were precipitated based on an internal crystallization process, and the crystals demonstrated a needlelike morphology. The study of the crystal growth of needlelike Sr-fluoroapatites gave a clear evidence of an Ostwald ripening mechanism.The formation of leucite, pollucite and Rb-leucite was based on a surface crystallization mechanism. Therefore, a twofold crystallization mechanism was successfully applied to develop these types of glass-ceramics. The main focus of this study was the controlled development of glass-ceramics exhibiting high radiopacity in comparison to the reference glass-ceramic. This goal could be achieved with all four glass-ceramics with the preferred development of the Sr-fluoroapatite – pollucite-type glass-ceramic. In addition to this main development, it was possible to control the thermal properties. Especially the Rb-leucite containing glass-ceramic showed the highest coefficient of thermal

  11. Raman band intensities of tellurite glasses.

    Science.gov (United States)

    Plotnichenko, V G; Sokolov, V O; Koltashev, V V; Dianov, E M; Grishin, I A; Churbanov, M F

    2005-05-15

    Raman spectra of TeO2-based glasses doped with WO3, ZnO, GeO2, TiO2, MoO3, and Sb2O3 are measured. The intensity of bands in the Raman spectra of MoO3-TeO2 and MoO3-WO3-TeO2 glasses is shown to be 80-95 times higher than that for silica glass. It is shown that these glasses can be considered as one of the most promising materials for Raman fiber amplifiers.

  12. Characterization of Low Density Glass Filled Epoxies

    National Research Council Canada - National Science Library

    Quesenberry, Matthew

    2003-01-01

    This report discusses the experimental determination and modeling of several thermophysical and mechanical properties of glass filled epoxy composite systems for potential use as electronic potting compounds...

  13. Degradation of glass in the soil

    Energy Technology Data Exchange (ETDEWEB)

    Romich, H.; Gerlach, S.; Mottner, P. [Fraunhofer-Institut fur Silicatforschung (ISC), Wertheim-Bronnbach (Germany)

    2004-07-01

    Full text of publication follows: Glass has been produced and used in Europe for over 2000 years. Glass objects from the Roman period onwards have been excavated during the last centuries. In general, Roman glass is chemically quite stable, and often the only sign of chemical alteration is an iridescent surface, caused by the leaching of cations, which leads to the formation of a hydrated silica-rich layer. Medieval potash glasses are much less durable, and their surfaces are often found deeply leached, sometimes to a point that no unaltered glass remains. These surfaces may be coherent, though fragile, or they are laminar, with no cohesion between the layers at all. In this study an analytical examination of a series of fragments of archaeological glass retrieved from different sites near Cologne and Stuttgart (Germany) has been carried out. Samples of corroded glasses were analysed by optical microscopy and SEM/EDX (surface and cross sections) in order to obtain information about the chemical composition of the bulk glass and the weathered layers. Since the environmental parameters have constantly varied for archaeological objects, mechanistic studies have to rely on laboratory experiments under controlled conditions. For an extensive exposure programme standardised soil or natural garden earth was used, for which the pH was modified. Several corrosion sensitive potash-lime silicate glasses have been designed to study the effect of glass composition. A model glass consisting of SiO{sub 2} (54.2), CaO (28.8) and K{sub 2}O (17.0 weight-%) mostly lead to the formation of a crust on the leached layer, with a total thickness of 100 micrometer (for soil with pH 7 to 8, 12 months exposure). Model glasses also containing Al, Mg and P have built up preferably laminated structures (total thickness up to 200 micrometer). This presentation will give an overview about the variety of degradation phenomena observed on originals and compare the results with controlled laboratory

  14. DEFENSE HIGH LEVEL WASTE GLASS DEGRADATION

    International Nuclear Information System (INIS)

    Ebert, W.

    2001-01-01

    The purpose of this Analysis/Model Report (AMR) is to document the analyses that were done to develop models for radionuclide release from high-level waste (HLW) glass dissolution that can be integrated into performance assessment (PA) calculations conducted to support site recommendation and license application for the Yucca Mountain site. This report was developed in accordance with the ''Technical Work Plan for Waste Form Degradation Process Model Report for SR'' (CRWMS M andO 2000a). It specifically addresses the item, ''Defense High Level Waste Glass Degradation'', of the product technical work plan. The AP-3.15Q Attachment 1 screening criteria determines the importance for its intended use of the HLW glass model derived herein to be in the category ''Other Factors for the Postclosure Safety Case-Waste Form Performance'', and thus indicates that this factor does not contribute significantly to the postclosure safety strategy. Because the release of radionuclides from the glass will depend on the prior dissolution of the glass, the dissolution rate of the glass imposes an upper bound on the radionuclide release rate. The approach taken to provide a bound for the radionuclide release is to develop models that can be used to calculate the dissolution rate of waste glass when contacted by water in the disposal site. The release rate of a particular radionuclide can then be calculated by multiplying the glass dissolution rate by the mass fraction of that radionuclide in the glass and by the surface area of glass contacted by water. The scope includes consideration of the three modes by which water may contact waste glass in the disposal system: contact by humid air, dripping water, and immersion. The models for glass dissolution under these contact modes are all based on the rate expression for aqueous dissolution of borosilicate glasses. The mechanism and rate expression for aqueous dissolution are adequately understood; the analyses in this AMR were conducted to

  15. Magnetic Glass Ceramics by Sintering of Borosilicate Glass and Inorganic Waste

    OpenAIRE

    Ponsot, In?s M. M. M.; Pontikes, Yiannis; Baldi, Giovanni; Chinnam, Rama K.; Detsch, Rainer; Boccaccini, Aldo R.; Bernardo, Enrico

    2014-01-01

    Ceramics and glass ceramics based on industrial waste have been widely recognized as competitive products for building applications; however, there is a great potential for such materials with novel functionalities. In this paper, we discuss the development of magnetic sintered glass ceramics based on two iron-rich slags, coming from non-ferrous metallurgy and recycled borosilicate glass. The substantial viscous flow of the glass led to dense products for rapid treatments at relatively low te...

  16. Influence of the glass particle size on the foaming process and physical characteristics of foam glasses

    DEFF Research Database (Denmark)

    König, Jakob; Petersen, Rasmus Rosenlund; Yue, Yuanzheng

    2016-01-01

    We have prepared low-density foam glasses from cathode-ray-tube panel glass using carbon and MnO2 as the foaming agents. The effect of the glass particle size on the foaming process, the apparent density and the pore morphology is revealed. The results show that the foaming is mainly caused...... by the reduction of manganese. Foam glasses with a density of

  17. Proceedings of the national conference on functional glasses/glass-ceramics and ceramics: souvenir

    International Nuclear Information System (INIS)

    2015-01-01

    This conference deals with issues relevant to functional glasses and glass ceramics which are technologically important materials for lasers, radioactive waste immobilization, radiation shielding, bio-glasses etc. It covers wide range of subjects and their applications right from managing the side effects of nuclear wastes and shielding the radiation, to sol-gel based bio-glass and its composites. Papers relevant to INIS are indexed separately

  18. Integrated Glass Coating Manufacturing Line

    Energy Technology Data Exchange (ETDEWEB)

    Brophy, Brenor [Enki Technology Inc., San Jose, CA (United States)

    2015-09-30

    This project aims to enable US module manufacturers to coat glass with Enki’s state of the art tunable functionalized AR coatings at the lowest possible cost and highest possible performance by encapsulating Enki’s coating process in an integrated tool that facilitates effective process improvement through metrology and data analysis for greater quality and performance while reducing footprint, operating and capital costs. The Phase 1 objective was a fully designed manufacturing line, including fully specified equipment ready for issue of purchase requisitions; a detailed economic justification based on market prices at the end of Phase 1 and projected manufacturing costs and a detailed deployment plan for the equipment.

  19. Do atmospheric aerosols form glasses?

    Directory of Open Access Journals (Sweden)

    D. A. Pedernera

    2008-09-01

    Full Text Available A new process is presented by which water soluble organics might influence ice nucleation, ice growth, chemical reactions and water uptake of aerosols in the upper troposphere: the formation of glassy aerosol particles. Glasses are disordered amorphous (non-crystalline solids that form when a liquid is cooled without crystallization until the viscosity increases exponentially and molecular diffusion practically ceases. The glass transition temperatures, Tg, homogeneous ice nucleation temperatures, Thom, and ice melting temperatures, Tm, of various aqueous inorganic, organic and multi-component solutions are investigated with a differential scanning calorimeter. The investigated solutes are: various polyols, glucose, raffinose, levoglucosan, an aromatic compound, sulfuric acid, ammonium bisulfate and mixtures of dicarboxylic acids (M5, of dicarboxylic acids and ammonium sulfate (M5AS, of two polyols, of glucose and ammonium nitrate, and of raffinose and M5AS. The results indicate that aqueous solutions of the investigated inorganic solutes show Tg values that are too low to be of atmospheric importance. In contrast, aqueous organic and multi-component solutions readily form glasses at low but atmospherically relevant temperatures (≤230 K. To apply the laboratory data to the atmospheric situation, the measured phase transition temperatures were transformed from a concentration to a water activity scale by extrapolating water activities determined between 252 K and 313 K to lower temperatures. The obtained state diagrams reveal that the higher the molar mass of the aqueous organic or multi-component solutes, the higher Tg of their respective solutions at a given water activity. To a lesser extent, Tg also depends on the hydrophilicity of the organic solutes. Therefore, aerosol particles containing larger (≳150 g mol−1 and

  20. Damages by radiation in glasses

    International Nuclear Information System (INIS)

    Olguin, F.; Gutierrez, C.; Cisniega, G.; Flores, J.H.; Golzarri, J.I.; Espinoza, G.

    1997-01-01

    As a part of the works carried out to characterize the electrons beam from the Pelletron accelerator of the Mexican Nuclear Center aluminium-silicate glass samples were irradiated. The purpose of these irradiations is to cause alterations in the amorphous microstructure of the material by means of the creation of color centers. The population density of these defects, consequence to the irradiation, is function of the exposure time which varied from 1 to 30 minutes, with an electronic beam energy of 400 keV, doing the irradiations at free atmosphere. the obtained spectra are correlated by damage which the radiation produced. (Author)

  1. Cation coordination in oxychloride glasses

    Energy Technology Data Exchange (ETDEWEB)

    Johnson, J A [Energy Technology Division, Argonne National Laboratory, Argonne, IL (United States); Holland, D [Physics Department, Warwick University, Coventry (United Kingdom); Bland, J [Physics Department, University of Liverpool, PO Box 147, Liverpool (United Kingdom); Johnson, C E [Physics Department, Northern Illinois University, DeKalb, IL (United States); Thomas, M F [Physics Department, University of Liverpool, PO Box 147, Liverpool (United Kingdom)

    2003-02-19

    Glasses containing mixtures of cations and anions of nominal compositions [Sb{sub 2}O{sub 3}]{sub x} - [ZnCl{sub 2}]{sub 1-x} where x = 0.25, 0.50, 0.75, and 1.00, have been studied by means of neutron diffraction and Raman and Moessbauer spectroscopy. There is preferential bonding within the system with the absence of Sb-Cl bonds. Antimony is found to be threefold coordinated to oxygen, and zinc fourfold coordinated. The main contributing species are of the form [Sb(OSb){sub 2}(OZn)] and [Zn(ClZn){sub 2}(OSb){sub 2}].

  2. Cation coordination in oxychloride glasses

    International Nuclear Information System (INIS)

    Johnson, J A; Holland, D; Bland, J; Johnson, C E; Thomas, M F

    2003-01-01

    Glasses containing mixtures of cations and anions of nominal compositions [Sb 2 O 3 ] x - [ZnCl 2 ] 1-x where x = 0.25, 0.50, 0.75, and 1.00, have been studied by means of neutron diffraction and Raman and Moessbauer spectroscopy. There is preferential bonding within the system with the absence of Sb-Cl bonds. Antimony is found to be threefold coordinated to oxygen, and zinc fourfold coordinated. The main contributing species are of the form [Sb(OSb) 2 (OZn)] and [Zn(ClZn) 2 (OSb) 2

  3. Storage and disposal of radioactive waste as glass in canisters

    International Nuclear Information System (INIS)

    Mendel, J.E.

    1978-12-01

    A review of the use of waste glass for the immobilization of high-level radioactive waste glass is presented. Typical properties of the canisters used to contain the glass, and the waste glass, are described. Those properties are used to project the stability of canisterized waste glass through interim storage, transportation, and geologic disposal

  4. Synthesis for Lunar Simulants: Glass, Agglutinate, Plagioclase, Breccia

    Science.gov (United States)

    Weinstein, Michael; Wilson, Stephen A.; Rickman, Douglas L.; Stoeser, Douglas

    2012-01-01

    The video describes a process for making glass for lunar regolith simulants that was developed from a patented glass-producing technology. Glass composition can be matched to simulant design and specification. Production of glass, pseudo agglutinates, plagioclase, and breccias is demonstrated. The system is capable of producing hundreds of kilograms of high quality glass and simulants per day.

  5. glasses

    Indian Academy of Sciences (India)

    thermogravimetric-differential thermal analysis and impedance spectroscopy. .... KT ). (2). Figure 4. Cole–cole plot of 60V2O5–5P2O5–33B2O3–2CeO2. ... According to this model, as .... Figure 13 represents the Nyquist plot for the composition.

  6. A Novel, Demountable Structural Glass System Out of Dry-Assembly, Interlocking Cast Glass Components

    NARCIS (Netherlands)

    Oikonomopoulou, F.; Bristogianni, T.; Barou, L.; Jacobs, Erwin; Frigo, G.; Veer, F.A.; Nijsse, R.; Louter, Christian; Bos, Freek; Belis, Jan; Veer, Fred; Nijsse, Rob

    Cast glass components are a promising solution for engineering pure glass structures of high transparency and load-carrying capacity due to their large cross-sectional area and monolithic nature. Currently, the few realized structures employing cast glass components rely either on a steel

  7. Comparison of a model vapor deposited glass films to equilibrium glass films

    Science.gov (United States)

    Flenner, Elijah; Berthier, Ludovic; Charbonneau, Patrick; Zamponi, Francesco

    Vapor deposition of particles onto a substrate held at around 85% of the glass transition temperature can create glasses with increased density, enthalpy, kinetic stability, and mechanical stability compared to an ordinary glass created by cooling. It is estimated that an ordinary glass would need to age thousands of years to reach the kinetic stability of a vapor deposited glass, and a natural question is how close to the equilibrium is the vapor deposited glass. To understand the process, algorithms akin to vapor deposition are used to create simulated glasses that have a higher kinetic stability than their annealed counterpart, although these glasses may not be well equilibrated either. Here we use novel models optimized for a swap Monte Carlo algorithm in order to create equilibrium glass films and compare their properties with those of glasses obtained from vapor deposition algorithms. This approach allows us to directly assess the non-equilibrium nature of vapor-deposited ultrastable glasses. Simons Collaboration on Cracking the Glass Problem and NSF Grant No. DMR 1608086.

  8. Reinforced glass beams composed of annealed, heat-strengthened and fully tempered glass

    NARCIS (Netherlands)

    Louter, P.C.; Belis, J.L.I.F.; Bos, F.P.; Veer, F.A.

    Annealed, heat-strengthened and fully tempered SG-laminated reinforced glass beam specimens were subjected to four-point bending tests to investigate the effects of glass type on their structural response. During the test the beams showed linear elastic response until initial glass failure, followed

  9. X-ray tomography of feed-to-glass transition of simulated borosilicate waste glasses

    Czech Academy of Sciences Publication Activity Database

    Harris, W.H.; Guillen, D.P.; Kloužek, Jaroslav; Pokorný, P.; Yano, T.; Lee, S.; Schweiger, M. J.; Hrma, P.

    2017-01-01

    Roč. 100, č. 9 (2017), s. 3883-3894 ISSN 0002-7820 Institutional support: RVO:67985891 Keywords : borosilicate glass * computed tomography * glass melting * morphology * nuclear waste * X-ray Subject RIV: JH - Ceramics, Fire-Resistant Materials and Glass OBOR OECD: Ceramics Impact factor: 2.841, year: 2016

  10. Analysis of elementary process steps in industrial glass melting tanks: some ideas on innovations in industrial glass melting

    NARCIS (Netherlands)

    Beerkens, R.G.C.

    2008-01-01

    Conventional industrial glass furnaces show broad glass melt residence time distributions in the melting tanks and average residence times may be up to more than two days for high quality glass products, such as float glass or TV glass, despite the minimum residence times of 8-10 hours (or even less

  11. ION EXCHANGE IN GLASS-CERAMICS

    Directory of Open Access Journals (Sweden)

    George Halsey Beall

    2016-08-01

    Full Text Available In the past few years ion-exchange in glasses has found a renewed interest with a lot of new development and research in industrial and academic labs and the commercialization of materials with outstanding mechanical properties. These glasses are now widely used in many electronic devices including hand-held displays and tablets. The exchange is generally conducted in a bath of molten salt below the transition temperature of the glass. The exchange at the surface of an alkali ion by a bigger one brings compressive stress at the surface. The mechanical properties are dependent on the stress level at the surface and the depth of penetration of the bigger ion. As compared to glasses, glass-ceramics have the interest to display a wide range of aspects (transparent to opaque and different mechanical properties (especially higher modulus and toughness. There has been little research on ion-exchange in glass-ceramics. In these materials the mechanisms are much more complex than in glasses because of their polyphasic nature: ion-exchange generally takes place mostly in one phase (crystalline phase or residual glass. The mechanism can be similar to what is observed in glasses with the replacement of an ion by another in the structure. But in some cases this ion-exchange leads to microstructural modifications (for example amorphisation or phase change.This article reviews these ion-exchange mechanisms using several transparent and opaque alumino-silicate glass-ceramics as examples. The effect of the ion exchange in the various glass-ceramics will be described, with particular emphasis on flexural strength.

  12. Development of new radiopaque glass fiber posts

    International Nuclear Information System (INIS)

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

    2016-01-01

    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 < 0.05) when evaluated with one-way ANOVA statistical analysis. According to combustion analyses, the filler content of the tested posts ranges between 58.84 wt.% and 86.02 wt.%. 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. Future glass 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. - Highlights: • AR glass fibers for dental applications • AR glass fibers have a great potential for obtaining radiopaque glass fiber posts. • Experimental AR glass fiber posts could be an alternative to commercial glass fiber posts for clinical application.

  13. Development of new radiopaque glass fiber posts

    Energy Technology Data Exchange (ETDEWEB)

    Furtos, Gabriel, E-mail: gfurtos@yahoo.co.uk [Raluca Ripan Institute of Research in Chemistry, Babes-Bolyai University, Cluj-Napoca (Romania); Baldea, Bogdan [Dep. of Prosthodontics, Faculty of Dental Medicine, Timisoara (Romania); Silaghi-Dumitrescu, Laura [Raluca Ripan Institute of Research in Chemistry, Babes-Bolyai University, Cluj-Napoca (Romania)

    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 < 0.05) when evaluated with one-way ANOVA statistical analysis. According to combustion analyses, the filler content of the tested posts ranges between 58.84 wt.% and 86.02 wt.%. 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. Future glass 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. - Highlights: • AR glass fibers for dental applications • AR glass fibers have a great potential for obtaining radiopaque glass fiber posts. • Experimental AR glass fiber posts could be an alternative to commercial glass fiber posts for clinical application.

  14. Wet water glass production plant

    Directory of Open Access Journals (Sweden)

    Stanković Mirjana S.

    2003-01-01

    Full Text Available The IGPC Engineering Department designed basic projects for a wet hydrate dissolution plant, using technology developed in the IGPC laboratories. Several projects were completed: technological, machine, electrical, automation. On the basis of these projects, a production plant of a capacity of 75,000 t/y was manufactured, at "Zeolite Mira", Mira (VE, Italy, in 1997. and 1998, increasing detergent zeolite production, from 50,000 to 100,000 t/y. Several goals were realized by designing a wet hydrate dissolution plant. The main goal was increasing the detergent zeolite production. The technological cycle of NaOH was closed, and no effluents emitted, and there is no pollution (except for the filter cake. The wet water glass production process is fully automatized, and the product has uniform quality. The production process can be controlled manually, which is necessary during start - up, and repairs. By installing additional process equipment (centrifugal pumps and heat exchangers technological bottlenecks were overcome, and by adjusting the operation of autoclaves, and water glass filters and also by optimizing the capacities of process equipment.

  15. Algebraic topology of spin glasses

    International Nuclear Information System (INIS)

    Koma, Tohru

    2011-01-01

    We study the topology of frustration in d-dimensional Ising spin glasses with d ≥ 2 with nearest-neighbor interactions. We prove the following. For any given spin configuration, the domain walls on the unfrustration network are all transverse to a frustrated loop on the unfrustration network, where a domain wall is defined to be a connected element of the collection of all the (d - 1)-cells which are dual to the bonds having an unfavorable energy, and the unfrustration network is the collection of all the unfrustrated plaquettes. These domain walls are topologically nontrivial because they are all related to the global frustration of a loop on the unfrustration network. Taking account of the thermal stability for the domain walls, we can explain the numerical results that three- or higher-dimensional systems exhibit a spin glass phase, whereas two-dimensional ones do not. Namely, in two dimensions, the thermal fluctuations of the topologically nontrivial domain walls destroy the order of the frozen spins on the unfrustration network, whereas they do not in three or higher dimensions. This may be interpreted as a global topological effect of the frustrations.

  16. Glass ionomer cement: literature review

    Directory of Open Access Journals (Sweden)

    Sérgio Spezzia

    2017-12-01

    Full Text Available Introduction: In the dental area preventive actions occur in an attempt to avoid the installation of caries, a disease that has an increased prevalence in the population and which is a Public Health problem. Some resources are used for such, such as: performing early diagnosis and the option for conservative treatments of minimal intervention. The glass ionomer cement (CIV, coming from its beneficial characteristics that meet current trends, is closely related to the precepts of Preventive and Minimally Invasive Dentistry and the new preservative techniques recommended. Objective: The objective of the present article was to carry out a literature review study, to determine the characteristics of CIV that has a prominent role in the Minimally Invasive Dentistry profile. Results: The dentist surgeon must be aware of the classification, according to its composition and physical-chemical nature: conventional ionomers; ionomers reinforced by metals; high viscosity and various types of resin modified glass ionomers to correctly choose the CIV that will be used in their clinical interventions, which should occur based on the properties of the material and its clinical indication. Conclusion: It was concluded that the implementation of preventive techniques with CIV in public health care, tend to minimize curative treatments, concurrently valuing the low complexity dental procedures performed in Primary Care, avoiding referrals for treatment of cases of greater complexity at the level Secondary and tertiary care, saving resources.

  17. Comment on 'Spherical 2+p spin-glass model: An analytically solvable model with a glass-to-glass transition'

    International Nuclear Information System (INIS)

    Krakoviack, V.

    2007-01-01

    Guided by old results on simple mode-coupling models displaying glass-glass transitions, we demonstrate, through a crude analysis of the solution with one step of replica symmetry breaking (1RSB) derived by Crisanti and Leuzzi for the spherical s+p mean-field spin glass [Phys. Rev. B 73, 014412 (2006)], that the phase behavior of these systems is not yet fully understood when s and p are well separated. First, there seems to be a possibility of glass-glass transition scenarios in these systems. Second, we find clear indications that the 1RSB solution cannot be correct in the full glassy phase. Therefore, while the proposed analysis is clearly naive and probably inexact, it definitely calls for a reassessment of the physics of these systems, with the promise of potentially interesting developments in the theory of disordered and complex systems

  18. Binary eutectic clusters and glass formation in ideal glass-forming liquids

    International Nuclear Information System (INIS)

    Lu, Z. P.; Shen, J.; Xing, D. W.; Sun, J. F.; Liu, C. T.

    2006-01-01

    In this letter, a physical concept of binary eutectic clusters in 'ideal' glass-forming liquids is proposed based on the characteristics of most well-known bulk metallic glasses (BMGs). The authors approach also includes the treatment of binary eutectic clusters as basic units, which leads to the development of a simple but reliable method for designing BMGs more efficiently and effectively in these unique glass-forming liquids. As an example, bulk glass formers with superior glass-forming ability in the Zr-Ni-Cu-Al and Zr-Fe-Cu-Al systems were identified with the use of the strategy

  19. Fiber glass reinforced structural materials for aerospace application

    Science.gov (United States)

    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.

  20. Hydrothermal metallurgy for recycling of slag and glass

    International Nuclear Information System (INIS)

    Tanaka, Toshihiro; Yoshikawa, Takeshi; Hirai, Nobumitsu; Katsuyama, Shigeru

    2009-01-01

    The authors have applied hydrothermal reactions to develop recycling processing of slag or glass. As an example, under hydrothermal conditions such as 200 300 deg. C and 30 40MPa with H 2 O, powders made of glass can be sintered to become solidified glass materials containing about 10mass% H 2 O. When the glass containing H 2 O is heated again under normal pressure, the glass expands releasing H 2 O to make porous microstructure. H 2 O starts to emit just above the glass transition temperature. Therefore, when we have a glass with low glass transition temperature, we can make low temperature foaming glass. The SiO 2 -Na 2 O-B 2 O 3 glass is a candidate to be such a foaming glass. In this paper, we describe our recent trial on the fabrication of the low temperature foaming glass by using hydrothermal reaction.

  1. Nano-Micro Materials Enabled Thermoelectricity From Window Glasses

    KAUST Repository

    Inayat, Salman Bin

    2012-01-01

    of individual glass strips to form the thickness depth of the glass on subsequent curing of the strips, and c) embedding nano-manufactured thermoelectric pillars, have been implemented for innovative integration of thermoelectric materials into window glasses

  2. Bulk metallic glasses: A new class of engineering materials

    Indian Academy of Sciences (India)

    M. Senthilkumar (Newgen Imaging) 1461 1996 Oct 15 13:05:22

    been discovered. Glass-forming ability depends on various factors like enthalpy ... The determination of a glass transition temperature in ... Rao (1980) has postulated that an alloy with the smallest possible molar volume is most prone to glass ...

  3. Crystallization study of Te–Bi–Se glasses

    Indian Academy of Sciences (India)

    Unknown

    Thermal stability; chalcogenide glasses; glass forming ability; glass transition temperature. 1. Introduction ... as well as their wide technological applications including threshold and ... are other important aspects such as ON-state current,.

  4. Setting of the Optimal Parameters of Melted Glass

    Czech Academy of Sciences Publication Activity Database

    Luptáková, Natália; Matejíčka, L.; Krečmer, N.

    2015-01-01

    Roč. 10, č. 1 (2015), s. 73-79 ISSN 1802-2308 Institutional support: RVO:68081723 Keywords : Striae * Glass * Glass melting * Regression * Optimal parameters Subject RIV: JH - Ceramics, Fire-Resistant Materials and Glass

  5. Nanoporous Glasses for Nuclear Waste Containment

    Directory of Open Access Journals (Sweden)

    Thierry Woignier

    2016-01-01

    Full Text Available Research is in progress to incorporate nuclear waste in new matrices with high structural stability, resistance to thermal shock, and high chemical durability. Interactions with water are important for materials used as a containment matrix for the radio nuclides. It is indispensable to improve their chemical durability to limit the possible release of radioactive chemical species, if the glass structure is attacked by corrosion. By associating high structural stability and high chemical durability, silica glass optimizes the properties of a suitable host matrix. According to an easy sintering stage, nanoporous glasses such as xerogels, aerogels, and composite gels are alternative ways to synthesize silica glass at relatively low temperatures (≈1,000–1,200°C. Nuclear wastes exist as aqueous salt solutions and we propose using the open pore structure of the nanoporous glass to enable migration of the solution throughout the solid volume. The loaded material is then sintered, thereby trapping the radioactive chemical species. The structure of the sintered materials (glass ceramics is that of nanocomposites: actinide phases (~100 nm embedded in a vitreous silica matrix. Our results showed a large improvement in the chemical durability of glass ceramic over conventional nuclear glass.

  6. Natural analogue study of volcanic glass

    International Nuclear Information System (INIS)

    Arai, T.; Yusa, Y.; Sasaki, N.; Tsunoda, N.; Takano, H.

    1989-02-01

    A considerable range in alteration rates of basaltic glasses in various environments has been reported in previous studies. However, these studies paid only cursory attention to the environmental conditions under which the glass had been altered. In this study, the alteration of basaltic glasses was investigated and the environmental conditions and the alteration rate were discussed. Two sample ages were represented: 280 years and 2800 years. Basaltic glasses and their alteration layers were analyzed by electron probe microanalyzer (EMPA) and the thickness of the alteration layers were measured by scanning electron microscope (SEM). The ground water collected near the sampling point of Zunazawa Scoria (2800 years) and the pore water of both samples were analyzed. The alteration temperature and flow rate of water are estimated to be about 13degC and 0.2 l/cm 2 /y respectively on the basis of meteorological data. The alteration layers of young aged basaltic glasses in freshwater conditions are similar to those of leached borosilicate glasses. The alteration rates of these basaltic glasses are estimated to be several μm/1000y. The elemental concentrations in the ground water can be roughly explained as the result of leaching of the glasses. (author)

  7. A Method to Produce Foam Glasses

    DEFF Research Database (Denmark)

    2016-01-01

    The present invention relates to a production process of foam glass from a mixture of glass cullet or slag or fly ash with a foaming agent and an oxidizing agent and heating to below 1100 C under low oxygen atmosphere. The invention relates more particularly to a process wherein pure carbon or a ...

  8. Characterising refractive index dispersion in chalcogenide glasses

    DEFF Research Database (Denmark)

    Fang, Y.; Sojka, L.; Jayasuriya, D.

    2016-01-01

    Much effort has been devoted to the study of glasses that contain the chalcogen elements (sulfur, selenium and tellurium) for photonics' applications out to MIR wavelengths. In this paper we describe some techniques for determining the refractive index dispersion characteristics of these glasses...

  9. Measurement of sound propagation in glass wool

    DEFF Research Database (Denmark)

    Tarnow, Viggo

    1995-01-01

    A new acoustic method for directly measuring the flow resistance, and the compressibility of fibrous materials such as glass wool, is given. Measured results for monochromatic sound in glass wool are presented and compared with theoretically calculated results. The agreement between experimental...

  10. Controlling break-the-glass through alignment

    NARCIS (Netherlands)

    Adriansyah, A.; Dongen, van B.F.; Zannone, N.

    2013-01-01

    Modern IT systems have to deal with unpredictable situations and exceptions more and more often. In contrast, security mechanisms are usually very rigid. Functionality like break-the-glass is thus employed to allow users to bypass security mechanisms in case of emergencies. However, break-the-glass

  11. The Glass Ceiling Initiative. A Report.

    Science.gov (United States)

    Department of Labor, Washington, DC.

    While minorities and women have made considerable gains in entering the workforce in the last few decades, there remains a dearth of minorities and women at management levels. This phenomenon has come to be known as the "glass ceiling." The Department of Labor defines the glass ceiling as those artificial barriers based on attitudinal or…

  12. Mixed cation effect in sodium aluminosilicate glasses

    DEFF Research Database (Denmark)

    Kjeldsen, Jonas; Smedskjær, Morten Mattrup; Mauro, John C.

    , network structure, and the resistances associated with the deformation processes in mixed cation glasses by partially substituting magnesium for calcium and calcium for lithium in sodium aluminosilicate glasses. We use Raman and 27Al NMR spectroscopies to obtain insights into the structural...

  13. Forming Glasses from Se and Te

    Directory of Open Access Journals (Sweden)

    Pierre Lucas

    2009-10-01

    Full Text Available Despite being close neighbors on the Periodic Table, selenium and tellurium present a totally different abilities to form glasses. Se is a very good glass former, and gives rise to numerous glass compositions which are popular for their transparency in the infrared range and their stability against crystallization. These glasses can be shaped into sophisticated optical devices such as optical fibers, planar guides or lenses. Nevertheless, their transparencies are limited at about 12 μm (depending on the thickness of the optical systems due to the relatively small mass of the Se element. On the other hand, tellurium is heavier and its use in substitution for Se permits to shift the IR cutoff beyond 20 μm. However, the semimetallic nature of Te limits its glass formation ability and this glass family is known to be unstable and consequently has found application as phase change material in the Digital Versatile Disk (DVD technology. In this paper, after a review of selenide glasses and their applications, it will be shown how, in a recent past, it has been possible to stabilize tellurium glasses by introducing new elements like Ga or I in their compositions.

  14. NMR studies of the structure of glasses

    International Nuclear Information System (INIS)

    Bray, P.J.; Gravina, S.J.; Stallworth, P.E.; Szu, S.P.; Jianhui Zhong

    1988-01-01

    Earlier continuous wave (CW) NMR studies of chemical bonding and structure in glasses are summarized. Examples are given of this use of the quadrupolar interaction and chemical shift to obtain structural information. New NMR data and analyses are presented for alkali borate and gallate glasses. Extensions to other elements (e.g. molybdenum, lanthanum) are suggested. 44 refs. (author)

  15. CLAY SOIL STABILISATION USING POWDERED GLASS

    Directory of Open Access Journals (Sweden)

    J. OLUFOWOBI

    2014-10-01

    Full Text Available This paper assesses the stabilizing effect of powdered glass on clay soil. Broken waste glass was collected and ground into powder form suitable for addition to the clay soil in varying proportions namely 1%, 2%, 5%, 10% and 15% along with 15% cement (base by weight of the soil sample throughout. Consequently, the moisture content, specific gravity, particle size distribution and Atterberg limits tests were carried out to classify the soil using the ASSHTO classification system. Based on the results, the soil sample obtained corresponded to Group A-6 soils identified as ‘fair to poor’ soil type in terms of use as drainage and subgrade material. This justified stabilisation of the soil. Thereafter, compaction, California bearing ratio (CBR and direct shear tests were carried out on the soil with and without the addition of the powdered glass. The results showed improvement in the maximum dry density values on addition of the powdered glass and with corresponding gradual increase up to 5% glass powder content after which it started to decrease at 10% and 15% powdered glass content. The highest CBR values of 14.90% and 112.91% were obtained at 5% glass powder content and 5mm penetration for both the unsoaked and soaked treated samples respectively. The maximum cohesion and angle of internal friction values of 17.0 and 15.0 respectively were obtained at 10% glass powder content.

  16. Aqueous solutions/nuclear glasses interactions

    International Nuclear Information System (INIS)

    Delage, F.; Advocat, T.; Vernaz, E.; Crovisier, J.L.

    1991-01-01

    Interactions results of the borosilicate glass used in radioactive wastes confinement and aqueous solutions at various temperature and PH show that for the glass components: - the release rate evolution follows an Arrhenius law, - in acid PH, there is a selective dissolution, - in basic PH, there is a stoechiometric dissolution [fr

  17. Plastic Deformation of Pressured Metallic Glass

    Directory of Open Access Journals (Sweden)

    Yun Cheng

    2017-11-01

    Full Text Available Although pressured metallic glass (MG has been reported in the literature; there are few studies focusing on pressure effects on the structure; dynamics and its plastic deformation. In this paper; we report on and characterize; via molecular dynamics simulation, the structure and dynamics heterogeneity of pressured MGs, and explore a causal link between local structures and plastic deformation mechanism of pressured glass. The results exhibit that the dynamical heterogeneity of metallic liquid is more pronounced at high pressure, while the MGs were less fragile after the release of external pressure, reflected by the non-Gaussian parameter (NGP. High pressure glass shows better plastic deformation; and the local strain zone distributed more uniformly than of in normal glass. Further research indicates that although the number of icosahedrons in pressured glass was much larger than that in normal glass, while the interpenetrating connections of icosahedra (ICOI exhibited spatial correlations were rather poor; In addition, the number of ‘fast’ atoms indexed by the atoms’ moving distance is larger than that in normal glass; leading to the sharp decreasing in number of icosahedrons during deformation. An uniform distribution of ‘fast’ atoms also contributed to better plastic deformation ability in the pressured glass. These findings may suggest a link between the deformation and destruction of icosahedra with short-range order.

  18. Oxygen diffusion in glasses and ceramic materials

    International Nuclear Information System (INIS)

    Kolitsch, A.; Richter, E.; Wolf, M.

    1978-10-01

    A survey is given on the published works to study oxygen diffusion in glasses and ceramic materials in the last years. In the first part methods are described for the measurement of oxygen diffusion coefficients and in the second part the published reports on oxygen diffusion in glasses, ceramic and other oxides are discussed. The most important results are summarized in different tables. (author)

  19. The Glass Ceiling: Progress and Persistent Challenges

    Science.gov (United States)

    McLlwain, Wendy M.

    2012-01-01

    It has been written that since 2001, there has not been any significant progress and the glass ceiling is still intact. Women are still underrepresented in top positions (Anonymous, 2004). If this is true, the glass ceiling presents a major barrier between women and their desire to advance into executive or senior management positions. In addition…

  20. Antibacterial properties of laser spinning glass nanofibers.

    Science.gov (United States)

    Echezarreta-López, M M; De Miguel, T; Quintero, F; Pou, J; Landin, M

    2014-12-30

    A laser-spinning technique has been used to produce amorphous, dense and flexible glass nanofibers of two different compositions with potential utility as reinforcement materials in composites, fillers in bone defects or scaffolds (3D structures) for tissue engineering. Morphological and microstructural analyses have been carried out using SEM-EDX, ATR-FTIR and TEM. Bioactivity studies allow the nanofibers with high proportion in SiO2 (S18/12) to be classified as a bioinert glass and the nanofibers with high proportion of calcium (ICIE16) as a bioactive glass. The cell viability tests (MTT) show high biocompatibility of the laser spinning glass nanofibers. Results from the antibacterial activity study carried out using dynamic conditions revealed that the bioactive glass nanofibers show a dose-dependent bactericidal effect on Sthaphylococcus aureus (S. aureus) while the bioinert glass nanofibers show a bacteriostatic effect also dose-dependent. The antibacterial activity has been related to the release of alkaline ions, the increase of pH of the medium and also the formation of needle-like aggregates of calcium phosphate at the surface of the bioactive glass nanofibers which act as a physical mechanism against bacteria. The antibacterial properties give an additional value to the laser-spinning glass nanofibers for different biomedical applications, such as treating or preventing surgery-associated infections. Copyright © 2014 Elsevier B.V. All rights reserved.

  1. Photoelastic response of permanently densified oxide glasses

    Science.gov (United States)

    Bechgaard, Tobias K.; Mauro, John C.; Thirion, Lynn M.; Rzoska, Sylwester J.; Bockowski, Michal; Smedskjaer, Morten M.

    2017-05-01

    The stress-induced birefringence (photoelastic response) in oxide glasses has important consequences for several applications, including glass for flat panel displays, chemically strengthened cover glass, and advanced optical glasses. While the effect of composition on the photoelastic response is relatively well documented, the effect of pressure has not been systematically studied. In this work, we evaluate the effect of hot isostatic compression on the photoelastic response of ten oxide glasses within two commonly used industrial glass families: aluminosilicates and boroaluminosilicates. Hot isostatic compression generally results in decreasing modifier-oxygen bond lengths and increasing network-former coordination numbers. These structural changes should lead to an increase in the stress optic coefficient (C) according to the model of Zwanziger et al., which can successfully predict the composition and structure dependence of C. However, in compressed glasses, we observe the opposite trend, viz., a decrease in the stress optic coefficient as a result of pressurization. We discuss this result based on measured changes in refractive index and elastic moduli within the context of atomic and lattice effects, building on the pioneering work of Mueller. We propose that the pressure-induced decrease in C is a result of changes in the shear modulus due to underlying topological changes in the glass network.

  2. The glass ceiling in nursing management.

    Science.gov (United States)

    Crawford, D I

    1993-01-01

    Women managers in business and health care have experienced discrimination related to advancement in management. Nurse executives must understand the strategies to overcome the barriers, the "glass ceiling," as well as implications for future practice. Women executives need an organized blueprint and the tools to dismantle the glass ceiling and overcome the political and discriminatory barriers to success.

  3. Surface layer effects on waste glass corrosion

    International Nuclear Information System (INIS)

    Feng, X.

    1993-01-01

    Water contact subjects waste glass to chemical attack that results in the formation of surface alteration layers. Two principal hypotheses have been advanced concerning the effect of surface alteration layers on continued glass corrosion: (1) they act as a mass transport barrier and (2) they influence the chemical affinity of the glass reaction. In general, transport barrier effects have been found to be less important than affinity effects in the corrosion of most high-level nuclear waste glasses. However, they can be important under some circumstances, for example, in a very alkaline solution, in leachants containing Mg ions, or under conditions where the matrix dissolution rate is very low. The latter suggests that physical barrier effect may affect the long-term glass dissolution rate. Surface layers influence glass reaction affinity through the effects of the altered glass and secondary phases on the solution chemistry. The reaction affinity may be controlled by various precipitates and crystalline phases, amorphous silica phases, gel layer, or all the components of the glass. The surface alteration layers influence radionuclide release mainly through colloid formation, crystalline phase incorporation, and gel layer retention. This paper reviews current understanding and uncertainties

  4. Affinity functions for modeling glass dissolution rates

    Energy Technology Data Exchange (ETDEWEB)

    Bourcier, W.L. [Lawrence Livermore National Lab., CA (United States)

    1997-07-01

    Glass dissolution rates decrease dramatically as glass approach ''saturation'' with respect to the leachate solution. Most repository sites are chosen where water fluxes are minimal, and therefore the waste glass is most likely to dissolve under conditions close to ''saturation''. The key term in the rate expression used to predict glass dissolution rates close to ''saturation'' is the affinity term, which accounts for saturation effects on dissolution rates. Interpretations of recent experimental data on the dissolution behaviour of silicate glasses and silicate minerals indicate the following: 1) simple affinity control does not explain the observed dissolution rate for silicate minerals or glasses; 2) dissolution rates can be significantly modified by dissolved cations even under conditions far from saturation where the affinity term is near unity; 3) the effects of dissolved species such as Al and Si on the dissolution rate vary with pH, temperature, and saturation state; and 4) as temperature is increased, the effect of both pH and temperature on glass and mineral dissolution rates decrease, which strongly suggests a switch in rate control from surface reaction-based to diffusion control. Borosilicate glass dissolution models need to be upgraded to account for these recent experimental observations. (A.C.)

  5. Rheological properties of potassium barium borate glasses

    NARCIS (Netherlands)

    Szwejda, K.A.; Vogel, D.L.; Stevels, J.M.

    1973-01-01

    Several series of potassium barium borate glasses have been investigated as to their rheological properties. It has been found, that all these glasses show deviations from ‘Newtonian’ behaviour below temperatures corresponding to viscosities of 1010 poises. The activation energies of viscous flow

  6. Glass binder development for a glass-bonded sodalite ceramic waste form

    International Nuclear Information System (INIS)

    Riley, Brian J.; Vienna, John D.; Frank, Steven M.; Kroll, Jared O.; Peterson, Jacob A.

    2017-01-01

    This paper discusses work to develop Na_2O-B_2O_3-SiO_2 glass binders for immobilizing LiCl-KCl eutectic salt waste in a glass-bonded sodalite waste form following electrochemical reprocessing of used metallic nuclear fuel. In this paper, five new glasses with ~20 mass% Na_2O were designed to generate waste forms with high sodalite. The glasses were then used to produce ceramic waste forms with a surrogate salt waste. The waste forms made using these new glasses were formulated to generate more sodalite than those made with previous baseline glasses for this type of waste. The coefficients of thermal expansion for the glass phase in the glass-bonded sodalite waste forms made with the new binder glasses were closer to the sodalite phase in the critical temperature region near and below the glass transition temperature than previous binder glasses used. Finally, these improvements should result in lower probability of cracking in the full-scale monolithic ceramic waste form, leading to better long-term chemical durability.

  7. Crack tip fracture toughness of base glasses for dental restoration glass-ceramics using crack opening displacements.

    Science.gov (United States)

    Deubener, J; Höland, M; Höland, W; Janakiraman, N; Rheinberger, V M

    2011-10-01

    The critical stress intensity factor, also known as the crack tip toughness K(tip), was determined for three base glasses, which are used in the manufacture of glass-ceramics. The glasses included the base glass for a lithium disilicate glass-ceramic, the base glass for a fluoroapatite glass-ceramic and the base glass for a leucite glass-ceramic. These glass-ceramic are extensively used in the form of biomaterials in restorative dental medicine. The crack tip toughness was established by using crack opening displacement profiles under experimental conditions. The crack was produced by Vickers indentation. The crack tip toughness parameters determined for the three glass-ceramics differed quite significantly. The crack tip parameters of the lithium disilicate base glass and the leucite base glass were higher than that of the fluoroapatite base glass. This last material showed glass-in-glass phase separation. The discussion of the results clearly shows that the droplet glass phase is softer than the glass matrix. Therefore, the authors conclude that a direct relationship exists between the chemical nature of the glasses and the crack tip parameter. Copyright © 2011 Elsevier Ltd. All rights reserved.

  8. Fusibility of medical glass in hospital waste incineration: Effect of glass components

    International Nuclear Information System (INIS)

    Jiang, X.G.; An, C.G.; Li, C.Y.; Fei, Z.W.; Jin, Y.Q.; Yan, J.H.

    2009-01-01

    Medical glass, which is the principal incombustible component in hospital wastes, has a bad influence on combustion. In a rotary kiln incinerator, medical glass melts and turns into slag, possibly adhering to the inner wall. Prediction of the melting characteristics of medical glass hence is important for preventing slagging. The effect of various glass components on fusibility has been investigated experimentally; that of Na 2 O is the most marked. The softening temperature and flow temperature decrease 19.8 o C and 34.0 o C, respectively, with a rise of Na 2 O content in the Basic Content (standard composition of medical glass) of 1%. Correlations between fusion temperatures and glass components have been investigated; predictive functions of four characteristic melting temperatures have been obtained by simplifying the multi-variant series and were verified by testing glass samples. Relative errors of fusion temperatures (computed vs. measured) are mostly less than 5%.

  9. Magnetic Glass Ceramics by Sintering of Borosilicate Glass and Inorganic Waste

    Directory of Open Access Journals (Sweden)

    Inès M. M. M. Ponsot

    2014-07-01

    Full Text Available Ceramics and glass ceramics based on industrial waste have been widely recognized as competitive products for building applications; however, there is a great potential for such materials with novel functionalities. In this paper, we discuss the development of magnetic sintered glass ceramics based on two iron-rich slags, coming from non-ferrous metallurgy and recycled borosilicate glass. The substantial viscous flow of the glass led to dense products for rapid treatments at relatively low temperatures (900–1000 °C, whereas glass/slag interactions resulted in the formation of magnetite crystals, providing ferrimagnetism. Such behavior could be exploited for applying the obtained glass ceramics as induction heating plates, according to preliminary tests (showing the rapid heating of selected samples, even above 200 °C. The chemical durability and safety of the obtained glass ceramics were assessed by both leaching tests and cytotoxicity tests.

  10. Bone bonding ability of some borate bio-glasses and their corresponding glass-ceramic derivatives

    Directory of Open Access Journals (Sweden)

    Fatma H. Margha

    2012-12-01

    Full Text Available Ternary borate glasses from the system Na2O·CaO·B2O3 together with soda-lime-borate samples containing 5 wt.% of MgO, Al2O3, SiO2 or P2O5 were prepared. The obtained glasses were converted to their glass-ceramic derivatives by controlled heat treatment. X-ray diffraction was employed to investigate the separated crystalline phases in glass-ceramics after heat treatment of the glassy samples. The glasses and corresponding glass-ceramics after immersion in water or diluted phosphate solution for extended times were characterized by the grain method (adopted by several authors and recommended by ASTM and Fourier-transform infrared spectra to justify the formation of hydroxyapatite as an indication of the bone bonding ability. The influence of glass composition on bioactivity potential was discussed too.

  11. Diffusion processes in nuclear waste glasses

    International Nuclear Information System (INIS)

    Serruys, Y.; Limoge, Y.; Brebec, G.

    1992-01-01

    Problems concerning the containment of nuclear wastes are presented. Different materials which have been considered for this purpose are briefly reviewed and we see why glass is one of the favorite candidates. It is focussed on what is known about diffusion in 'simple enough' glasses. After a recall concerning the structure and possible defects, the main results on diffusion in 'simple' glasses are given and it is shown what these results involve for the mechanisms of diffusion. The diffusion models are presented which can account for transport in random media: percolation and random walk models. Specific phenomena for the nuclear waste glasses are considered: the effect of irradiation on diffusion and leaching (i.e. corrosion by water). Finally diffusion data in nuclear waste glasses are presented. (author). 199 refs., 6 figs., 1 tab

  12. Decontamination processes for waste glass canisters

    International Nuclear Information System (INIS)

    Rankin, W.N.

    1981-06-01

    The process which will be used to decontaminate waste glass canisters at the Savannah River Plant consists of: decontamination (slurry blasting); rinse (high-pressure water); and spot decontamination (high-pressure water plus slurry). No additional waste will be produced by this process because glass frit used in decontamination will be mixed with the radioactive waste and fed into the glass melter. Decontamination of waste glass canisters with chemical and abrasive blasting techniques was investigated. The ability of a chemical technique with HNO 3 -HF and H 2 C 2 O 4 to remove baked-on contamination was demonstrated. A correlation between oxide removal and decontamination was observed. Oxide removal and, thus, decontamination by abrasive blasting techniques with glass frit as the abrasive was proposed and demonstrated

  13. Densification of silica glass at ambient pressure

    International Nuclear Information System (INIS)

    Zheng Lianqing; An Qi; Fu Rongshan; Ni Sidao; Luo, S.-N.

    2006-01-01

    We show that densification of silica glass at ambient pressure as observed in irradiation experiments can be attributed to defect generation and subsequent structure relaxation. In our molecular dynamics simulations, defects are created by randomly removing atoms, by displacing atoms from their nominal positions in an otherwise intact glass, and by assigning certain atom excess kinetic energy (simulated ion implantation). The former forms vacancies; displacing atoms and ion implantation produce both vacancies and 'interstitials'. Appreciable densification is induced by these defects after equilibration of the defective glasses. The structural and vibrational properties of the densified glasses are characterized, displaying resembling features regardless of the means of densification. These results indicate that relaxation of high free-energy defects into metastable amorphous structures enriched in atomic coordination serves as a common mechanism for densification of silica glass at ambient pressure

  14. Radiation-induced centers in inorganic glasses

    International Nuclear Information System (INIS)

    Brekhovskikh, S.M.; Tyul'nin, V.A.

    1988-01-01

    The nature, structure and formation mechanisms of radiation-induced colour centers, EPR, luminescence, generated ionizing radiation in nonorganic oxide glasses are considered. Experimental material covering both fundamental aspects of radiation physics and glass chemistry, and aspects intimately connected with the creation of new materials with the given radiation-spectral characteristics, with possibilities to prepare radiation-stable and radiation-sensitive glasses is systematized and generalized. Considerable attention is paid to the detection of radiation-induced center binding with composition, glass structures redox conditions for their synthesis. Some new possibilities of practical application of glasses with radiation-induced centers, in particular, to record optical information are reflected in the paper

  15. Measurements of natural radioactivity in historical glasses

    International Nuclear Information System (INIS)

    Kierzek, J.; Kunicki-Goldfinger, J.J.; Kasprzak, A.J.

    2000-01-01

    Natural radioactive components of historical glasses and two methods of the respective measurement of the radioactivity are discussed. The evaluation of radioactivity of glass objects using a Geiger-Mueller counter and high-resolution gamma ray spectrometry is presented. A survey of the Warsaw National Museum glass collection with a Geiger-Mueller counter allowed distinguishing the vessels made of potassium and sodium glass by their level of natural radioactivity. Gamma spectrometry, on the other hand, enables estimating a specific radionuclide content. Special attention is given to uranium glasses. One 19th century Bohemian vessel, coloured with a uranium compound, was carefully examined using gamma spectrometry. K 2 O and U content were estimated to be 16.2 and 0.33%, respectively. (orig.)

  16. Bioactive glass coatings for orthopedic metallic implants

    Energy Technology Data Exchange (ETDEWEB)

    Lopez-Esteban, Sonia; Saiz, Eduardo; Fujino, Sigheru; Oku, Takeo; Suganuma, Katsuaki; Tomsia, Antoni P.

    2003-06-30

    The objective of this work is to develop bioactive glass coatings for metallic orthopedic implants. A new family of glasses in the SiO2-Na2O-K2O-CaO-MgO-P2O5 system has been synthesized and characterized. The glass properties (thermal expansion, softening and transformation temperatures, density and hardness) are in line with the predictions of established empirical models. The optimized firing conditions to fabricate coatings on Ti-based and Co-Cr alloys have been determined and related to the glass properties and the interfacial reactions. Excellent adhesion to alloys has been achieved through the formation of 100-200 nm thick interfacial layers (Ti5Si3 on Ti-based alloys and CrOx on Co-Cr). Finally, glass coatings, approximately 100 mu m thick, have been fabricated onto commercial Ti alloy-based dental implants.

  17. Radionuclides containment in nuclear glasses. An overview

    Energy Technology Data Exchange (ETDEWEB)

    Gin, Stephane; Jollivet, Patrick; Tribet, Magaly; Peuget, Sylvain; Schuller, Sophie [CEA Marcoule, Bagnols-sur-Ceze (France). DE2D SEVT

    2017-07-01

    Radioactive waste vitrification has been carried out industrially in several countries for nearly 40 years. Research into the formulation and long term behavior of high and intermediate level waste glasses, mainly borosilicate compositions, is still continuing in order to (i) safely condition new types of wastes and (ii) design and demonstrate the safety of the disposal of these long-lived waste forms in a deep geological repository. This article presents a summary of current knowledge on the formulation, irradiation resistance and the chemical durability of these conditioning materials, with a special focus on the fate of radionuclides during glass processing and aging. It is shown that, apart from the situation for certain elements with very low incorporation rate in glass matrices, vitrification in borosilicate glass can enable waste loadings of up to ∝20 wt% while maintaining the glass homogeneity for geological time scales and guaranteeing a high stability level in spite of irradiation and water contact.

  18. The chemical durability of alkali aluminosilicate glasses

    International Nuclear Information System (INIS)

    Tait, J.C.; Mandolesi, D.L.

    1983-09-01

    The aqueous durabilities of a series of glasses based on the sodium aluminosilicate system (Na 2 O-Al 2 O 3 -SiO 2 ) have been studied. The effects of molecular substitution of K 2 O or CaO for Na 2 O, and B 2 O 3 for Al 2 O 3 have been investigated. The temperature dependence of leaching in the Na 2 O-B 2 O 3 -Al 2 O 3 -SiO 2 system was studied with glasses containing 2 wt percent simulated UO 2 fuel recycle waste. The results confirm that aluminosilicate glasses are more durable than their borosilicate counterparts. The leaching results are explained in terms of glass structure and bonding, and a general leaching mechanism for aluminosilicate glasses is presented

  19. Corrosion of simulated nuclear waste glass

    International Nuclear Information System (INIS)

    Music, S.; Ristic, M.; Gotic, M.; Foric, J.

    1988-01-01

    In this study the preparation and characterization of borosilicate glasses of different chemical composition were investigated. Borosilicate glasses were doped with simulated nuclear waste oxides. The chemical corrosion in water of these glasses was followed by measuring the leach rates as a function of time. It was found that a simulated nuclear waste glass with the chemical composition (weight %), 15.61% Na 2 O, 10.39% B 2 O 3 , 45.31% SiO 2 , 13.42% ZnO, 6.61% TiO 2 and 8.66% waste oxides, is characterized by low melting temperature and with good corrosion resistance in water. Influence of passive layers on the leaching behaviour of nuclear waste glasses is discussed. (author) 20 refs.; 7 figs.; 4 tabs

  20. Predicting Shear Transformation Events in Metallic Glasses

    Science.gov (United States)

    Xu, Bin; Falk, Michael L.; Li, J. F.; Kong, L. T.

    2018-03-01

    Shear transformation is the elementary process for plastic deformation of metallic glasses, the prediction of the occurrence of the shear transformation events is therefore of vital importance to understand the mechanical behavior of metallic glasses. In this Letter, from the view of the potential energy landscape, we find that the protocol-dependent behavior of shear transformation is governed by the stress gradient along its minimum energy path and we propose a framework as well as an atomistic approach to predict the triggering strains, locations, and structural transformations of the shear transformation events under different shear protocols in metallic glasses. Verification with a model Cu64 Zr36 metallic glass reveals that the prediction agrees well with athermal quasistatic shear simulations. The proposed framework is believed to provide an important tool for developing a quantitative understanding of the deformation processes that control mechanical behavior of metallic glasses.

  1. 57Fe Moessbauer effect in borosilicate glasses

    International Nuclear Information System (INIS)

    Music, S.

    1989-01-01

    The present study was carried out to elucidate the valence state of iron and its co-ordination in borosilicate glasses, which are being investigated as possible solidification matrices for the immobilization of a simulated nuclear waste. 57 Fe Mossbauer spectroscopy was used as the experimental technique. The chemical compositions of glass samples and the experimental conditions for the preparation of these samples are given. Iron in the form of haematite (α-Fe 2 O 3 ) was used as doping material. Details of the experimental procedure have previously been described. Isomer shifts are calculated relative to α-iron. The results indicate a strong dependence of the valency of the iron and its coordination on the chemical composition of the glass and the Fe 2 O 3 content. The method of preparing the glasses also influences the state of the iron in oxide glasses. (Author)

  2. Experimental design of a waste glass study

    International Nuclear Information System (INIS)

    Piepel, G.F.; Redgate, P.E.; Hrma, P.

    1995-04-01

    A Composition Variation Study (CVS) is being performed to support a future high-level waste glass plant at Hanford. A total of 147 glasses, covering a broad region of compositions melting at approximately 1150 degrees C, were tested in five statistically designed experimental phases. This paper focuses on the goals, strategies, and techniques used in designing the five phases. The overall strategy was to investigate glass compositions on the boundary and interior of an experimental region defined by single- component, multiple-component, and property constraints. Statistical optimal experimental design techniques were used to cover various subregions of the experimental region in each phase. Empirical mixture models for glass properties (as functions of glass composition) from previous phases wee used in designing subsequent CVS phases

  3. Decontamination processes for waste glass canisters

    International Nuclear Information System (INIS)

    Rankin, W.N.

    1981-01-01

    The process which will be used to decontaminate waste glass canisters at the Savannah River Plant consists of: decontamination (slurry blasting); rinse (high-pressure water); and spot decontamination (high-pressure water plus slurry). No additional waste will be produced by this process because glass frit used in decontamination will be mixed with the radioactive waste and fed into the glass melter. Decontamination of waste glass canisters with chemical and abrasive blasting techniques was investigated. The ability of a chemical technique with HNO 3 -HF and H 2 C 2 O 4 to remove baked-on contamination was demonstrated. A correlation between oxide removal and decontamination was observed. Oxide removal and, thus, decontamination by abrasive blasting techniques with glass frit as the abrasive was proposed and demonstrated

  4. Preface JFDE Special Issue Glass

    Directory of Open Access Journals (Sweden)

    Ulrich Knaack

    2015-05-01

    Full Text Available Facade Design and Engineering is a multidisciplinary field that touches many other scientific disciplines. Glass is one of the key materials for building envelopes, and a strong scientific community has developed over the last decade. Designers love glass for its transparency. It is strong but brittle and very demanding in terms of engineering. We continuously see new innovative developments in terms of its climatic performance, structural possibilities, construction design and new applications. Reason enough to dedicate this special issue to the topic. The issue would not have been possible without the contribution of our special editors Jan Belis and Christian Louter, who contributed through their outstanding editorial work and network. Most of the papers in this issue were carefully selected from of a number of invited submissions and conference papers of the COST Action TU0905 Mid-Term Conference, April 17+18 2013, Porec, (CRC Press/Balkema, Leiden and subsequently subjected to the regular blind review process of the journal. Glass as a building material demonstrates the nature of the architectural discipline, where science and building practice are closely linked. Buildings are the live testing bed for scientific research and, at the same time, building practice formulates new research questions. We found that many articles sent to us deal with this relation. Therefore we decided to introduce the new category ’Applied Practice’ for certain journal paper contributions, which from now on can be found at the end of each issue. Although they do not need to be purely scientific, ’Applied Practice’ papers will always discuss new developments, will have a clear structure and are subjected to the strict JFDE review process. Façade Design and Engineering is a peer reviewed, open access journal, funded by The Netherlands Organisation for Scientific Research NWO (www.nwo.nl. We see ’open access’ as the future publishing model. But it

  5. Late Byzantine mineral soda high alumina glasses from Asia Minor: a new primary glass production group.

    Directory of Open Access Journals (Sweden)

    Nadine Schibille

    Full Text Available The chemical characterisation of archaeological glass allows the discrimination between different glass groups and the identification of raw materials and technological traditions of their production. Several lines of evidence point towards the large-scale production of first millennium CE glass in a limited number of glass making factories from a mixture of Egyptian mineral soda and a locally available silica source. Fundamental changes in the manufacturing processes occurred from the eight/ninth century CE onwards, when Egyptian mineral soda was gradually replaced by soda-rich plant ash in Egypt as well as the Islamic Middle East. In order to elucidate the supply and consumption of glass during this transitional period, 31 glass samples from the assemblage found at Pergamon (Turkey that date to the fourth to fourteenth centuries CE were analysed by electron microprobe analysis (EPMA and by laser ablation-inductively coupled plasma-mass spectrometry (LA-ICP-MS. The statistical evaluation of the data revealed that the Byzantine glasses from Pergamon represent at least three different glass production technologies, one of which had not previously been recognised in the glass making traditions of the Mediterranean. While the chemical characteristics of the late antique and early medieval fragments confirm the current model of glass production and distribution at the time, the elemental make-up of the majority of the eighth- to fourteenth-century glasses from Pergamon indicate the existence of a late Byzantine glass type that is characterised by high alumina levels. Judging from the trace element patterns and elevated boron and lithium concentrations, these glasses were produced with a mineral soda different to the Egyptian natron from the Wadi Natrun, suggesting a possible regional Byzantine primary glass production in Asia Minor.

  6. Constructing nature behind the glass

    Directory of Open Access Journals (Sweden)

    Samuel J.M.M. Alberti

    2008-07-01

    Full Text Available By way of introducing this special issue of Museum and Society, ‘Constructing nature behind glass’, this paper first surveys the literature devoted to analyses of natural history objects and collections. Such work is to be found in interesting places – not only in museum studies, history of science, and professional museum literature, but also in visual studies, anthropology and cultural geography. After exploiting this writing for different perspectives on the cultural and practical construction of museum nature, this paper moves on to consider one popular topic, taxidermy. The ambiguous nature of taxidermic mounts, or ‘remnant models’, leads to a discussion of the relative status of specimen and artefact. I identify four configurations of their relationship: museum nature as opposed to material culture; museum nature as material culture; museum nature and material culture sharing parallel processes; and finally, museum nature and material culture entangled. All offer perspectives on the construction of nature and culture behind glass.

  7. Cell approach to glass transition

    International Nuclear Information System (INIS)

    Aste, Tomaso; Coniglio, Antonio

    2003-01-01

    We present a novel theoretical approach to understanding the complex dynamics of glass-forming liquids, granular packings and amorphous solids. This theory, which is an elaboration of the free volume and inherent structure approaches, allows one to retrieve the thermodynamical properties of these systems from studies of geometrical and topological properties of local, static configurations alone. When applied to hard-sphere systems, the present theory reproduces with a good quantitative agreement the equation of state for the crystalline and the disordered glassy phases. Moreover, we find that, as the density approaches a critical value close to the random close-packing density, the configurational entropy approaches zero and the large relaxation time diverges according to the Vogel-Fulcher behaviour, following also the Adam-Gibbs relation

  8. Solid oxide fuel cell having a glass composite seal

    Science.gov (United States)

    De Rose, Anthony J.; Mukerjee, Subhasish; Haltiner, Jr., Karl Jacob

    2013-04-16

    A solid oxide fuel cell stack having a plurality of cassettes and a glass composite seal disposed between the sealing surfaces of adjacent cassettes, thereby joining the cassettes and providing a hermetic seal therebetween. The glass composite seal includes an alkaline earth aluminosilicate (AEAS) glass disposed about a viscous glass such that the AEAS glass retains the viscous glass in a predetermined position between the first and second sealing surfaces. The AEAS glass provides geometric stability to the glass composite seal to maintain the proper distance between the adjacent cassettes while the viscous glass provides for a compliant and self-healing seal. The glass composite seal may include fibers, powders, and/or beads of zirconium oxide, aluminum oxide, yttria-stabilized zirconia (YSZ), or mixtures thereof, to enhance the desirable properties of the glass composite seal.

  9. Crystallization in high-level waste glass: A review of glass theory and noteworthy literature

    Energy Technology Data Exchange (ETDEWEB)

    Christian, J. H. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL)

    2015-08-18

    There is a fundamental need to continue research aimed at understanding nepheline and spinel crystal formation in high-level waste (HLW) glass. Specifically, the formation of nepheline solids (K/NaAlSiO4) during slow cooling of HLW glass can reduce the chemical durability of the glass, which can cause a decrease in the overall durability of the glass waste form. The accumulation of spinel solids ((Fe, Ni, Mn, Zn)(Fe, Cr)2O4), while not detrimental to glass durability, can cause an array of processing problems inside HLW glass melters. In this review, the fundamental differences between glass and solid-crystals are explained using kinetic, thermodynamic, and viscosity arguments, and several highlights of glass-crystallization research, as it pertains to high-level waste vitrification, are described. In terms of mitigating spinel in the melter and both spinel and nepheline formation in the canister, the complexity of HLW glass and the intricate interplay between thermal, chemical, and kinetic factors further complicates this understanding. However, new experiments seeking to elucidate the contributing factors of crystal nucleation and growth in waste glass, and the compilation of data from older experiments, may go a long way towards helping to achieve higher waste loadings while developing more efficient processing strategies. Higher waste loadings and more efficient processing strategies will reduce the overall HLW Hanford Tank Waste Treatment and Immobilization Plant (WTP) vitrification facilities mission life.

  10. Crystallization in high-level waste glass: A review of glass theory and noteworthy literature

    Energy Technology Data Exchange (ETDEWEB)

    Christian, J. H. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL)

    2015-08-01

    There is a fundamental need to continue research aimed at understanding nepheline and spinel crystal formation in high-level waste (HLW) glass. Specifically, the formation of nepheline solids (K/NaAlSiO₄) during slow cooling of HLW glass can reduce the chemical durability of the glass, which can cause a decrease in the overall durability of the glass waste form. The accumulation of spinel solids ((Fe, Ni, Mn, Zn)(Fe,Cr)₂O₄), while not detrimental to glass durability, can cause an array of processing problems inside of HLW glass melters. In this review, the fundamental differences between glass and solid-crystals are explained using kinetic, thermodynamic, and viscosity arguments, and several highlights of glass-crystallization research, as it pertains to high-level waste vitrification, are described. In terms of mitigating spinel in the melter and both spinel and nepheline formation in the canister, the complexity of HLW glass and the intricate interplay between thermal, chemical, and kinetic factors further complicates this understanding. However, new experiments seeking to elucidate the contributing factors of crystal nucleation and growth in waste glass, and the compilation of data from older experiments, may go a long way towards helping to achieve higher waste loadings while developing more efficient processing strategies.

  11. Studies on Bi-Sr-Ca-Cu-O glasses and superconducting glass ceramics

    International Nuclear Information System (INIS)

    Singh, R.; Zacharias, E.

    1991-01-01

    Bi-Sr-Ca-Cu-O glasses and glass ceramics of various compositions were synthesised. The glass transition temperature varies from 396 to 422degC depending on the glass composition. The bulk glass ceramics of 4334, 4336, 2223 and 4246 compositions show superconductivity when the corresponding glass samples were heat-treated in air at 820degC for 3, 9, 12 and 24 h respectively. X-ray diffraction studies show that the superconducting phase present in all these compositions is Bi 2 Sr 2 Ca 1 Cu 2 O x . The 4334 glass ceramic is almost a single-phase material with a preferred orientation such that the c axis is normal to the sample surface. The 2223 glass ceramic has a higher T c (onset) than the other three compositions indicating the presence of high T c phase (110 K) also. ESR studies on the glass samples indicate the existence of Cu 2+ . The effect of heat treatment on ESR shows that the intensity of resonance decreases with increase in heat-treatment duration. This effect is more pronounced for the 4334 and 2223 compositions. The advantages of synthesizing superconducting materials by glass route are discussed in view of practical applications. (author). 9 refs., 6 figs

  12. Studies on the Potential of Waste Soda Lime Silica Glass in Glass Ionomer Cement Production

    Directory of Open Access Journals (Sweden)

    V. W. Francis Thoo

    2013-01-01

    Full Text Available Glass ionomer cements (GIC are produced through acid base reaction between calcium-fluoroaluminosilicate glass powder and polyacrylic acid (PAA. Soda lime silica glasses (SLS, mainly composed of silica (SiO2, have been utilized in this study as the source of SiO2 for synthesis of Ca-fluoroaluminosilicate glass. Therefore, the main objective of this study was to investigate the potential of SLS waste glass in producing GIC. Two glasses, GWX 1 (analytical grade SiO2 and GWX 2 (replacing SiO2 with waste SLS, were synthesized and then characterized using X-ray diffraction (XRD and energy dispersive X-ray (EDX. Synthesized glasses were then used to produce GIC, in which the properties were characterized using Fourier transform infrared spectroscopy (FT-IR and compressive test (from 1 to 28 days. XRD results showed that amorphous glass was produced by using SLS waste glass (GWX 2, which is similar to glass produced using analytical grade SiO2 (GWX 1. Results from FT-IR showed that the setting reaction of GWX 2 cements is slower compared to cement GWX 1. Compressive strengths for GWX 1 cements reached up to 76 MPa at 28 days, whereas GWX 2 cements showed a slightly higher value, which is 80 MPa.

  13. A simple method for tuning the glass transition process in inorganic phosphate glasses

    Science.gov (United States)

    Fulchiron, René; Belyamani, Imane; Otaigbe, Joshua U.; Bounor-Legaré, Véronique

    2015-02-01

    The physical modification of glass transition temperature (Tg) and properties of materials via blending is a common practice in industry and academia and has a large economic advantage. In this context, simple production of hitherto unattainable new inorganic glass blends from already existing glass compositions via blending raises much hope with the potential to provide new glasses with new and improved properties, that cannot be achieved with classical glass synthesis, for a plethora of applications such as computers screens, glass-to-metal seals, and storage materials for nuclear wastes. Here, we demonstrate that blends of the specific glass compositions studied are miscible in all proportions, an unreported phenomenon in hard condensed matter like glass. Interestingly, excellent agreement was found between the obtained data and calculated Tgs from theoretical equations (Supplementary information) for predicting the composition dependence of Tg for miscible blends with weak but significant specific interactions between the blend components. That this blending method is at present not applied to inorganic glasses reflects the fact that water and chemically resistant phosphate glasses with relatively low Tgs have become available only recently.

  14. Critical review of glass performance modeling

    International Nuclear Information System (INIS)

    Bourcier, W.L.

    1994-07-01

    Borosilicate glass is to be used for permanent disposal of high-level nuclear waste in a geologic repository. Mechanistic chemical models are used to predict the rate at which radionuclides will be released from the glass under repository conditions. The most successful and useful of these models link reaction path geochemical modeling programs with a glass dissolution rate law that is consistent with transition state theory. These models have been used to simulate several types of short-term laboratory tests of glass dissolution and to predict the long-term performance of the glass in a repository. Although mechanistically based, the current models are limited by a lack of unambiguous experimental support for some of their assumptions. The most severe problem of this type is the lack of an existing validated mechanism that controls long-term glass dissolution rates. Current models can be improved by performing carefully designed experiments and using the experimental results to validate the rate-controlling mechanisms implicit in the models. These models should be supported with long-term experiments to be used for model validation. The mechanistic basis of the models should be explored by using modern molecular simulations such as molecular orbital and molecular dynamics to investigate both the glass structure and its dissolution process

  15. Immobilization of Chloroperoxidase on Aminopropyl-Glass

    Science.gov (United States)

    Kadima, Tenshuk A.; Pickard, Michael A.

    1990-01-01

    Chloroperoxidase (CPO) purified from Caldariomyces fumago CMI 89362 was covalently bound to aminopropyl-glass by using a modification of an established method. Acid-washed glass was derivatized by using aminopropyltriethoxysilane, and the enzyme was ionically bound at low ionic strength. Further treatment with glutaraldehyde covalently linked the enzyme to the glass beads in an active form. No elution of bound activity from glass beads could be detected with a variety of washings. The loading of enzyme protein to the glass beads was highest, 100 mg of CPO per g of glass, at high reaction ratios of CPO to glass, but the specific activity of the immobilized enzyme was highest, 36% of theoretical, at low enzyme-to-carrier ratios. No differences in the properties of the soluble and immobilized enzymes could be detected by a number of criteria: their pH-activity and pH-stability profiles were similar, as were their thermal stabilities. After five uses, the immobilized enzyme retained full activity between pH 6.0 and 6.7. PMID:16348352

  16. Crystal growth in zinc borosilicate glasses

    Science.gov (United States)

    Kullberg, Ana T. G.; Lopes, Andreia A. S.; Veiga, João P. B.; Monteiro, Regina C. C.

    2017-01-01

    Glass samples with a molar composition (64+x)ZnO-(16-x)B2O3-20SiO2, where x=0 or 1, were successfully synthesized using a melt-quenching technique. Based on differential thermal analysis data, the produced glass samples were submitted to controlled heat-treatments at selected temperatures (610, 615 and 620 °C) during various times ranging from 8 to 30 h. The crystallization of willemite (Zn2SiO4) within the glass matrix was confirmed by means of X-ray diffraction (XRD) and scanning electron microscopy (SEM). Under specific heat-treatment conditions, transparent nanocomposite glass-ceramics were obtained, as confirmed by UV-vis spectroscopy. The influence of temperature, holding time and glass composition on crystal growth was investigated. The mean crystallite size was determined by image analysis on SEM micrographs. The results indicated an increase on the crystallite size and density with time and temperature. The change of crystallite size with time for the heat-treatments at 615 and 620 °C depended on the glass composition. Under fixed heat-treatment conditions, the crystallite density was comparatively higher for the glass composition with higher ZnO content.

  17. Viscosity properties of sodium borophosphate glasses

    International Nuclear Information System (INIS)

    Gaylord, S.; Tincher, B.; Petit, L.; Richardson, K.

    2009-01-01

    The viscosity behavior of (1 - x)NaPO 3 -xNa 2 B 4 O 7 glasses (x = 0.05-0.20) have been measured as a function of temperature using beam-bending and parallel-plate viscometry. The viscosity was found to shift to higher temperatures with increasing sodium borate content. The kinetic fragility parameter, m, estimated from the viscosity curve, decreases from 52 to 33 when x increases from 0.05 to 0.20 indicating that the glass network transforms from fragile to strong with the addition of Na 2 B 4 O 7 . The decrease in fragility with increasing x is due to the progressive depolymerization of the phosphate network by the preferred four-coordinated boron atoms present in the low alkali borate glasses. As confirmed by Raman spectroscopy increasing alkali borate leads to enhanced B-O-P linkages realized with the accompanying transition from solely four-coordinated boron (in BO 4 units) to mixed BO 4 /BO 3 structures. The glass viscosity characteristics of the investigated glasses were compared to those of P-SF67 and N-FK5 commercial glasses from SCHOTT. We showed that the dependence of the viscosity of P-SF67 was similar to the investigated glasses due to similar phosphate network organization confirmed by Raman spectroscopy, whereas N-FK5 exhibited a very different viscosity curve and fragility parameter due to its highly coordinated silicate network

  18. Nuclear waste immobilization in iron phosphate glasses

    International Nuclear Information System (INIS)

    Garcia, D.A.; Rodriguez, Diego A.; Menghini, Jorge E.; Bevilacqua, Arturo

    2007-01-01

    Iron-phosphate glasses have become important in the nuclear waste immobilization area because they have some advantages over silicate-based glasses, such as a lower processing temperature and a higher nuclear waste load without losing chemical and mechanical properties. Structure and chemical properties of iron-phosphate glasses are determined in terms of the main components, in this case, phosphate oxide along with the other oxides that are added to improve some of the characteristics of the glasses. For example, Iron oxide improves chemical durability, lead oxide lowers fusion temperature and sodium oxide reduces viscosity at high temperature. In this work a study based on the composition-property relations was made. We used different techniques to characterize a series of iron-lead-phosphate glasses with uranium and aluminium oxide as simulated nuclear waste. We used the Arquimedes method to determine the bulk density, differential temperature analysis (DTA) to determine both glass transition temperature and crystallization temperature, dilatometric analysis to calculate the linear thermal expansion coefficient, chemical durability (MCC-1 test) and X-ray diffraction (XRD). We also applied some theoretic models to calculate activation energies associated with the glass transition temperature and crystallization processes. (author)

  19. Bonding silicon nitride using glass-ceramic

    International Nuclear Information System (INIS)

    Dobedoe, R.S.

    1995-01-01

    Silicon nitride has been successfully bonded to itself using magnesium-aluminosilicate glass and glass-ceramic. For some samples, bonding was achieved using a diffusion bonder, but in other instances, following an initial degassing hold, higher temperatures were used in a nitrogen atmosphere with no applied load. For diffusion bonding, a small applied pressure at a temperature below which crystallisation occurs resulted in intimate contact. At slightly higher temperatures, the extent of the reaction at the interface and the microstructure of the glass-ceramic joint was highly sensitive to the bonding temperature. Bonding in a nitrogen atmosphere resulted in a solution-reprecipitation reaction. A thin layer of glass produced a ''dry'', glass-free joint, whilst a thicker layer resulted in a continuous glassy join across the interface. The chromium silicide impurities within the silicon nitride react with the nucleating agent in the glass ceramic, which may lead to difficulty in producing a fine glass-ceramic microstructure. Slightly lower temperatures in nitrogen resulted in a polycrystalline join but the interfacial contact was poor. It is hoped that one of the bonds produced may be developed to eventually form part of a graded joint between silicon nitride and a high temperature nickel alloy. (orig.)

  20. Glass ceramic-to-metal seals

    Science.gov (United States)

    Not Available

    1982-04-19

    A glass ceramic composition prepared by subjecting a glass composition comprising, by weight, 65 to 80% SiO/sub 2/, 8 to 16% Li/sub 2/O, 2 to 8% Al/sub 2/O/sub 3/, 1 to 8% K/sub 2/O, 1 to 5% P/sub 2/O/sub 5/ and 1.5 to 7% B/sub 2/O/sub 3/, to the following processing steps of heating the glass composition to a temperature sufficient to crystallize lithium metasilicate therein, holding the glass composition at a temperature and for a time period sufficient to dissolve the lithium metasilicate therein thereby creating cristobalite nucleii, cooling the glass composition and maintaining the composition at a temperature and for a time period sufficient to recrystallize lithium metasilicate therein, and thermally treating the glass composition at a temperature and for a time period sufficient to caus growth of cristobalite and further crystallization of lithium metasilicate producing a glass ceramic composition having a specific thermal expansion coefficient and products containing said composition.

  1. Temperature effects on waste glass performance

    International Nuclear Information System (INIS)

    Mazer, J.J.

    1991-02-01

    The temperature dependence of glass durability, particularly that of nuclear waste glasses, is assessed by reviewing past studies. The reaction mechanism for glass dissolution in water is complex and involves multiple simultaneous reaction proceeded, including molecular water diffusion, ion exchange, surface reaction, and precipitation. These processes can change in relative importance or dominance with time or changes in temperature. The temperature dependence of each reaction process has been shown to follow an Arrhenius relationship in studies where the reaction process has been isolated, but the overall temperature dependence for nuclear waste glass reaction mechanisms is less well understood, Nuclear waste glass studies have often neglected to identify and characterize the reaction mechanism because of difficulties in performing microanalyses; thus, it is unclear if such results can be extrapolated to other temperatures or reaction times. Recent developments in analytical capabilities suggest that investigations of nuclear waste glass reactions with water can lead to better understandings of their reaction mechanisms and their temperature dependences. Until a better understanding of glass reaction mechanisms is available, caution should be exercised in using temperature as an accelerating parameter. 76 refs., 1 tab

  2. Aging of a Binary Colloidal Glass

    Science.gov (United States)

    Lynch, Jennifer M.; Cianci, Gianguido C.; Weeks, Eric R.

    2008-03-01

    After having undergone a glass transition, a glass is in a non-equilibrium state, and its properties depend on the time elapsed since vitrification. We study this phenomenon, known as aging. In particular, we study a colloidal suspension consisting of micron-sized particles in a liquid --- a good model system for studying the glass transition. In this system, the glass transition is approached by increasing the particle concentration, instead of decreasing the temperature. We observe samples composed of particles of two sizes (d1= 1.0μm and d2= 2.0μm) using fast laser scanning confocal microscopy, which yields real-time, three-dimensional movies deep inside the colloidal glass. We then analyze the trajectories of several thousand particles as the glassy suspension ages. Specifically, we look at how the size, motion and structural organization of the particles relate to the overall aging of the glass. We find that areas richer in small particles are more mobile and therefore contribute more to the structural changes found in aging glasses.

  3. Surface chemistry and durability of borosilicate glass

    International Nuclear Information System (INIS)

    Carroll, S.A.; Bourcier, W.L.; Phillips, B.L.

    1994-01-01

    Important glass-water interactions are poorly understood for borosilicate glass radioactive waste forms. Preliminary results show that glass durability is dependent on reactions occurring at the glass-solution interface. CSG glass (18.2 wt. % Na 2 O, 5.97 wt. % CaO, 11.68 wt. % Al 2 O 3 , 8.43 wt. % B 2 O 3 , and 55.73 wt. % SiO 2 ) dissolution and net surface H + and OH - adsorption are minimal at near neutral pH. In the acid and alkaline pH regions, CSG glass dissolution rates are proportional to [H + ] adsorbed 2 and [OH - ] adsorbed 0.8 , respectively. In contrast, silica gel dissolution and net H + and OH - adsorption are minimal and independent of pH in acid to neutral solutions. In the alkaline pH region, silica gel dissolution is proportional to [OH - ] adsorbed 0.9 adsorbed . Although Na adsorption is significant for CSG glass and silica gel in the alkaline pH regions, it is not clear if it enhances dissolution, or is an artifact of depolymerization of the framework bonds

  4. Method of manufacturing borosilicate glass solidification products

    International Nuclear Information System (INIS)

    Tanaka, Tsuneya.

    1986-01-01

    Purpose: To obtain glass solidification products efficiently in a dry process from medium and high level radioactive liquid wastes discharged from PWR type reactors. Method: Boric acid-containing radioactive liquid wastes generated from primary coolants of PWR type reactors are evaporated to condensate as the pre-treatment. The concentrated liquid wastes are supplied to a drum type rotary kiln. While on the other hand, usual glass frits are introduced into the kiln. The liquid wastes are dried in the rotary kiln, as well as B 2 O 3 and the glass frits in the liquid wastes are combined into glass particles. In this case, since the kiln is rotated, no glass particles are deposited on the wall of the kiln. Then, the glass particles are introduced for melting into a high frequency melting furnace made of metal. The melting temperature is set to 1100 - 1150 deg C. The molten borosilicate glass is recovered from the bottom of the melting furance, contained in a canister and cooled for several hours, and then a cover is welded to the canister. (Ikeda, J.)

  5. Diffusion and ionic conduction in oxide glasses

    International Nuclear Information System (INIS)

    Mehrer, H; Imre, A W; Tanguep-Nijokep, E

    2008-01-01

    The ion transport properties of soda-lime silicate and alkali borate glasses have been studied with complimentary tracer diffusion and impedance spectroscopy techniques in order to investigate the ion dynamics and mixed-alkali effect (MAE). In soda-lime silicate glasses the tracer diffusivity of 22 Na alkali ions is more than six orders of magnitude faster than the diffusivity of earth alkali 45 Ca ions. This observation is attributed to a stronger binding of bivalent earth alkali ions to the glass network as compared to that of alkali ions. The conductivity of the investigated standard soda-lime silicate glasses is mostly due to the high mobility of sodium ions and a temperature independent Haven ratio of about 0.45 is obtained. For single alkali sodium-borate glasses, the Haven ratio is also temperature independent, however, it is decreases with decreasing temperature for rubidium-borate glass. The MAE was investigated for Na-Rb borate glasses and it was observed that the tracer diffusivities of 22 Na and 86 Rb ions cross, when plotted as function of the relative alkali content. This crossover occurs near the Na/(Na+Rb) ratio of the conductivity minimum due to MAE. The authors suggest that this crossover and the trend of diffusion coefficients is the key to an understanding of the MAE

  6. Viscosity properties of tellurite-based glasses

    International Nuclear Information System (INIS)

    Tincher, B.; Massera, J.; Petit, L.; Richardson, K.

    2010-01-01

    The viscosity behavior of glasses with the composition (90-x)TeO 2 -10Bi 2 O 3 -xZnO with x = 15, 17.5, and 20 (TBZ glasses) and 80TeO 2 -(20-y)Na 2 O-yZnO system with y = 0, 5, and 10 (TNZ glasses) have been measured as a function of temperature using a beam-bending (BBV) and a parallel-plate (PPV) viscometer. The structure of the glass' network has been characterized using Raman spectroscopy and has been related to the viscosity temperature behavior and the fragility parameter (m) of the glasses. As the concentration of ZnO in the TBZ system (x) increases, the fragility parameter of the glass increases, whereas it decreases with an increase of the ZnO concentration (y) in the TNZ system. In both glasses, these variations in m have been related to the partial depolymerization of the tellurite network associated with the level of modifier content. The depolymerization of the tellurite network is believed to be the result of a reduction in the number of [TeO 4 ] units and the formation of [TeO 3 ] and [TeO 3+1 ] units that occurs with a change in TeO 2 content in the TBZ system and modifier content in the TNZ system.

  7. Toward a consistent model for glass dissolution

    International Nuclear Information System (INIS)

    Strachan, D.M.; McGrail, B.P.; Bourcier, W.L.

    1994-01-01

    Understanding the process of glass dissolution in aqueous media has advanced significantly over the last 10 years through the efforts of many scientists around the world. Mathematical models describing the glass dissolution process have also advanced from simple empirical functions to structured models based on fundamental principles of physics, chemistry, and thermodynamics. Although borosilicate glass has been selected as the waste form for disposal of high-level wastes in at least 5 countries, there is no international consensus on the fundamental methodology for modeling glass dissolution that could be used in assessing the long term performance of waste glasses in a geologic repository setting. Each repository program is developing their own model and supporting experimental data. In this paper, we critically evaluate a selected set of these structured models and show that a consistent methodology for modeling glass dissolution processes is available. We also propose a strategy for a future coordinated effort to obtain the model input parameters that are needed for long-term performance assessments of glass in a geologic repository. (author) 4 figs., tabs., 75 refs

  8. Dynamics and thermodynamics of polymer glasses.

    Science.gov (United States)

    Cangialosi, D

    2014-04-16

    The fate of matter when decreasing the temperature at constant pressure is that of passing from gas to liquid and, subsequently, from liquid to crystal. However, a class of materials can exist in an amorphous phase below the melting temperature. On cooling such materials, a glass is formed; that is, a material with the rigidity of a solid but exhibiting no long-range order. The study of the thermodynamics and dynamics of glass-forming systems is the subject of continuous research. Within the wide variety of glass formers, an important sub-class is represented by glass forming polymers. The presence of chain connectivity and, in some cases, conformational disorder are unfavourable factors from the point of view of crystallization. Furthermore, many of them, such as amorphous thermoplastics, thermosets and rubbers, are widely employed in many applications. In this review, the peculiarities of the thermodynamics and dynamics of glass-forming polymers are discussed, with particular emphasis on those topics currently the subject of debate. In particular, the following aspects will be reviewed in the present work: (i) the connection between the pronounced slowing down of glassy dynamics on cooling towards the glass transition temperature (Tg) and the thermodynamics; and, (ii) the fate of the dynamics and thermodynamics below Tg. Both aspects are reviewed in light of the possible presence of a singularity at a finite temperature with diverging relaxation time and zero configurational entropy. In this context, the specificity of glass-forming polymers is emphasized.

  9. Critical review of glass performance modeling

    Energy Technology Data Exchange (ETDEWEB)

    Bourcier, W.L. [Lawrence Livermore National Lab., CA (United States)

    1994-07-01

    Borosilicate glass is to be used for permanent disposal of high-level nuclear waste in a geologic repository. Mechanistic chemical models are used to predict the rate at which radionuclides will be released from the glass under repository conditions. The most successful and useful of these models link reaction path geochemical modeling programs with a glass dissolution rate law that is consistent with transition state theory. These models have been used to simulate several types of short-term laboratory tests of glass dissolution and to predict the long-term performance of the glass in a repository. Although mechanistically based, the current models are limited by a lack of unambiguous experimental support for some of their assumptions. The most severe problem of this type is the lack of an existing validated mechanism that controls long-term glass dissolution rates. Current models can be improved by performing carefully designed experiments and using the experimental results to validate the rate-controlling mechanisms implicit in the models. These models should be supported with long-term experiments to be used for model validation. The mechanistic basis of the models should be explored by using modern molecular simulations such as molecular orbital and molecular dynamics to investigate both the glass structure and its dissolution process.

  10. Utilization of recycled glass derived from cathode ray tube glass as fine aggregate in cement mortar

    International Nuclear Information System (INIS)

    Ling, Tung-Chai; Poon, Chi-Sun

    2011-01-01

    Graphical abstract: Display Omitted Highlights: → A recycling/treatment process to remove lead on funnel glass surface is described. → Utilizing recycled funnel glass in mortar can reduce hazardous CRT glass wastes. → Effects of CRT glass content on the properties of cement mortar are studied. → Fly ash can effectively mitigate ASR expansion of mortar even at 100% glass content. → Alkaline medium in cement matrix successfully prevented the leaching of lead. - Abstract: Rapid advances in the electronic industry led to an excessive amount of early disposal of older electronic devices such as computer monitors and old televisions (TV) before the end of their useful life. The management of cathode ray tubes (CRT), which have been a key component in computer monitors and TV sets, has become a major environmental problem worldwide. Therefore, there is a pressing need to develop sustainable alternative methods to manage hazardous CRT glass waste. This study assesses the feasibility of utilizing CRT glass as a substitute for natural aggregates in cement mortar. The CRT glass investigated was an acid-washed funnel glass of dismantled CRT from computer monitors and old TV sets. The mechanical properties of mortar mixes containing 0%, 25%, 50%, 75% and 100% of CRT glass were investigated. The potential of the alkali-silica reaction (ASR) and leachability of lead were also evaluated. The results confirmed that the properties of the mortar mixes prepared with CRT glass was similar to that of the control mortar using sand as fine aggregate, and displayed innocuous behaviour in the ASR expansion test. Incorporating CRT glass in cement mortar successfully prevented the leaching of lead. We conclude that it is feasible to utilize CRT glass in cement mortar production.

  11. Chemistry and kinetics of waste glass corrosion

    International Nuclear Information System (INIS)

    Bates, J.K.

    1996-01-01

    Under repository disposal conditions, the reaction of glass with water comprises the source term for release of radionuclides to the near-field environment. An understanding of glass reaction and the manner by which radionuclides are released is needed to design the waste package and to evaluate the total performance of the repository. The ASTM Standard C-1174-91 provides a general methodology for obtaining information related to the behavior of glass. This paper reviews the application of this standard to glass reaction. In the first step in the ASTM approach, the researcher identifies the materials and the conditions under which the long-term behavior is to be determined. Glass compositions have undergone a genesis over the past 15 years in response to concerns about feed streams, processing, and durability. A range of borosilicate compositions has been identified, but as new applications for vitrification occur, for example, immobilization of weapons plutonium and residue from plutonium processing, different compositions must be evaluated. The repository environment depends on the spatial emplacement of waste containers (glass and spent fuel), and both open-quotes hotclose quotes and open-quotes coldclose quotes scenarios have been proposed for the Yucca Mountain site. Regardless of the exact configuration, the near-field hydrology is expected to be unsaturated: that is, the waste packages are contacted initially by water vapor, and ultimately by small amounts of dripping or standing water. The behavior of glass can be studied as a function of composition within the constraints the environmental conditions place on the physical parameters that affect glass reaction (temperature, radiation field, groundwater composition, etc.). In the second step, the researcher reviews the literature and proposes a reaction pathway by which glass reacts in an unsaturated environment

  12. Microporous glasses for pro-ecological applications

    International Nuclear Information System (INIS)

    Procyk, B.; Stoch, L.; Kubacki, M.; Rewilak, M.; Soltysiak, J.

    1994-01-01

    Microporous glasses are obtained by appropriate thermal and chemical treatment. On account of their sorptive properties microporous glasses represent an excellent material for storing high-energy radioactive waste products in nuclear power engineering and for binding toxins in natural environment. Microporous glasses may be used as membranes non-organic, as gel filling in chromatography. They may find application in biochemistry, chemical, metallurgical, electrochemical and other industries. The above applications depend on the internal arrangement, size and shape of pores. (author). 4 refs, 4 figs, 1 tab

  13. Bioactive glasses materials, properties and applications

    CERN Document Server

    Ylänen, Heimo

    2011-01-01

    Due to their biocompatibility and bioactivity, bioactive glasses are used as highly effective implant materials throughout the human body to replace or repair damaged tissue. As a result, they have been in continuous use since shortly after their invention in the late 1960s and are the subject of extensive research worldwide.Bioactive glasses provides readers with a detailed review of the current status of this unique material, its properties, technologies and applications. Chapters in part one deal with the materials and mechanical properties of bioactive glass, examining topics such

  14. Ultrahigh stability of atomically thin metallic glasses

    Energy Technology Data Exchange (ETDEWEB)

    Cao, C. R.; Huang, K. Q.; Zhao, N. J.; Sun, Y. T.; Bai, H. Y.; Gu, L., E-mail: l.gu@iphy.ac.cn, E-mail: dzheng@iphy.ac.cn, E-mail: whw@iphy.ac.cn; Zheng, D. N., E-mail: l.gu@iphy.ac.cn, E-mail: dzheng@iphy.ac.cn, E-mail: whw@iphy.ac.cn; Wang, W. H., E-mail: l.gu@iphy.ac.cn, E-mail: dzheng@iphy.ac.cn, E-mail: whw@iphy.ac.cn [Institute of Physics, Chinese Academy of Sciences, Beijing 100190 (China)

    2014-07-07

    We report the fabrication and study of thermal stability of atomically thin ZrCu-based metallic glass films. The ultrathin films exhibit striking dynamic properties, ultrahigh thermal stability, and unique crystallization behavior with discrete crystalline nanoparticles sizes. The mechanisms for the remarkable high stability and crystallization behaviors are attributed to the dewetting process of the ultrathin film. We demonstrated a promising avenue for understanding some fundamental issues such as glassy structure, crystallization, deformation, and glass formation through atomic resolution imaging of the two dimensional like metallic glasses.

  15. Sustainable Innovation of Glass Design and Craft

    DEFF Research Database (Denmark)

    Sparre-Petersen, Maria

    2014-01-01

    but an ongoing process of re-directing the way we design our world and thereby our future. This approach along with further research into sustainable development within the field of design and combined with material specific methodologies may reveal new possibilities for sustainable as well as aesthetic...... windows to beads. Glass is a natural material and can be found in nature in the form of i.e. obsidian and fulgurites. Glass in itself does not impact the environment negatively, but mining and transportation of raw materials and production of new glass products contributes to CO2 emission. Therefore...

  16. Preliminary characterization of glass fiber sizing

    DEFF Research Database (Denmark)

    Petersen, Helga Nørgaard; Kusano, Yukihiro; Brøndsted, Povl

    2013-01-01

    Glass fiber surfaces are treated with sizing during manufacturing. Sizing consists of several components, including a film former and a silane coupling agent that is important for adhesion between glass fibers and a matrix. Although the sizing highly affects the composite interface and thus...... the strength of the composites, little is known about the structure and chemistry of the sizing. A part of sizing was extracted by soxhlet extraction. The fibers were subsequently burned and some fibers were merely burned for analysis of glass fiber and sizing. The results showed that the analyzed fibers had...

  17. Excitation Chains at the Glass Transition

    International Nuclear Information System (INIS)

    Langer, J. S.

    2006-01-01

    The excitation-chain theory of the glass transition, proposed in an earlier publication, predicts diverging, super-Arrhenius relaxation times and, via a similarly diverging length scale, suggests a way of understanding the relations between dynamic and thermodynamic properties of glass-forming liquids. I argue here that critically large excitation chains play a role roughly analogous to that played by critical clusters in the droplet model of vapor condensation. Unlike a first-order condensation point in a vapor, the glass transition is not a conventional phase transformation, and may not be a thermodynamic transition at all

  18. Irradiation test of borosilicate glass burnable poison

    International Nuclear Information System (INIS)

    Feng Mingquan; Liao Zumin; Yang Mingjin; Lu Changlong; Huang Deyang; Zeng Wangchun; Zhao Xihou

    1991-08-01

    The irradiation test and post-irradiation examinations for borosilicate glass burnable poison are introduced. Examinations include visual examination, measurement of dimensions and density, and determination of He gas releasing and 10 B burnup. The corrosion and phenomenon of irradiation densification are also discussed. Two type glass samples have been irradiated with different levels of neutron flux. It proved that the GG-17 borosilicate glass can be used as burnable poison to replace the 10 B stainless steel in the Qinshan Nuclear Power Plant, and it is safe, economical and reasonable

  19. Thulium-based bulk metallic glass

    International Nuclear Information System (INIS)

    Yu, H. B.; Yu, P.; Wang, W. H.; Bai, H. Y.

    2008-01-01

    We report the formation and properties of a thulium-based bulk metallic glass (BMG). Compared with other known rare-earth (RE) based BMGs, Tm-based BMGs show features of excellent glass formation ability, considerable higher elastic modulus, smaller Poisson's ratio, high mechanical strength, and intrinsic brittleness. The reasons for the different properties between the Tm-based and other RE-based BMGs are discussed. It is expected that the Tm-based glasses with the unique properties are appropriate candidates for studying some important issues in BMGs

  20. Structure peculiarities of mixed alkali silicate glasses

    International Nuclear Information System (INIS)

    Bershtein, V.A.; Gorbachev, V.V.; Egorov, V.

    1980-01-01

    The thermal porperties and structure of alkali and mixed alkali (Li, Na, K) silicate glasses by means of differential scanning calorimetry (DSC), the positron annihilation method, X-ray fluorescence and infrared (300-30 cm -1 ) spectroscopy were studied. Introduction of different alkali cations in glass results in nonadditive change in their electron structure (bond covalence degree growth) and the thermal behaviour. The different manifestations of mixed alkali effect can be explained by the lessening of long distance Coulomb interactions and strengthening the short-range forces in the mixed alkali glasses. (orig.)

  1. Radiation shielding application of lead glass

    International Nuclear Information System (INIS)

    Nathuram, R.

    2017-01-01

    Nuclear medicine and radiotherapy centers equipped with high intensity X-ray or teletherapy sources use lead glasses as viewing windows to protect personal from radiation exposure. Lead is the main component of glass which is responsible for shielding against photons. It is therefore essential to check the shielding efficiency before they are put in use. This can be done by studying photon transmission through the lead glasses. The study of photon transmission in shielding materials has been an important subject in medical physics and is potential useful in the development of radiation shielding materials

  2. Immobilization of Uranium Silicides in Sintered Glass

    International Nuclear Information System (INIS)

    Mateos, P.; Russo, D.O.; Heredia, A.D.; Sanfilippo, M.

    2003-01-01

    High activity nuclear spent fuels vitrification by fusion is a well known technology which has industrial scale in France, England, Japan, EEUU. Borosilicates glasses are used in this process.Sintered glasses are an alternative to the immobilization task in which there is also a wide experience around the world.The available technics are: cold pressing and sintering , hot-pressing and hot isostatic pressing.This work compares Borosilicates and Iron silicates sintered glasses behaviour when different ammounts of nuclear simulated waste is added

  3. Copper oxide content dependence of crystallization behavior, glass forming ability, glass stability and fragility of lithium borate glasses

    International Nuclear Information System (INIS)

    Soliman, A.A.; Kashif, I.

    2010-01-01

    Differential thermal analysis (DTA) and X-ray diffraction (XRD) have been employed to investigate the copper oxide content dependence of the glass transition temperatures data, activation energy for the glass transition E t , glass stability GS, fragility index Fi, the glass-forming ability (GFA) and crystallization behavior of {(100-x) mol% Li 2 B 4 O 7 -x mol% CuO} glass samples, where x=0-40 mol% CuO. From the dependence of the glass transition temperature T g on the heating rate β, the fragility, F i , and the activation energy, E t , have been calculated. It is seen that F i and E t are attained their minimum values at 0 x -T g , SCL region and the GS. The GFA has been investigated on the basis of Hruby parameter K H , which is a strong indicator of GFA, and the relaxation time. Results of GFA are in good agreement with the fragility index, F i , calculations indicating that {90Li 2 B 4 O 7 .10CuO} is the best glass former. The stronger glass forming ability has decreasing the fragility index. XRD result indicates that no fully amorphous samples but a mixture of crystalline and amorphous phases are formed in the samples containing x>25 mol% CuO and below it composed of glassy phase. Increasing the CuO content above 25 mol% helps the crystallization process, and thus promotes a distinct SCL region. XRD suggests the presence of micro-crystallites of remaining residual amorphous matrix by increasing the CuO content.

  4. Glass heat capacity and its abrupt change in glass transition region

    DEFF Research Database (Denmark)

    Yue, Yuanzheng; Smedskjær, Morten Mattrup; Mauro, John C.

    cover a large range of glass formers from metallic to non-metallic glasses. To conduct this study we convert the units of all the Cp data from J/mol K and J/g K to J/g-atom K. This study will provide insight into the correlations among chemical bonding, microstructure structure, liquid fragility, glass......Glass transition (GT) has been a fascinating, but challenging subject in the condensed matter science over decades. Despite progress in understanding GT, many crucial problems still need to be clarified. One of the problems deals with the microscopic origin of abrupt change of heat capacity (Cp......) around glass transition. Here we study this problem through two approaches. First, we analyze the Cp change with temperature on homologous series of glass formers (i.e., with regular compositional substitution). Second, we do the same on non-homologous systems (e.g. without regular compositional...

  5. Facing slag glass and slag glass ceramic produced from thermal power plant ash

    Energy Technology Data Exchange (ETDEWEB)

    Buruchenko, A.E.; Kolesnikov, A.A.; Lukoyanov, A.G.

    1990-10-01

    Evaluates properties of fly ash and slags from the Krasnoyarsk coal-fired power plants and their utilization for glass and ceramic glass production. Composition of a mixture of fly ash and slag was: silica 40-55%, aluminium oxides 10-40%, ferric trioxide 6-14%, calcium oxides 20-35%, magnesium oxides 3-6%, potassium oxides 0.3-1.5%, sodium oxides 0.2-05%, sulfur trioxide 0.9-5.0%. The analyzed fly ash and slags from the Krasnoyarsk plant were an economic waste material for glass production. Properties of sand, clay and other materials used in glass production and properties of glass and ceramic glass produced on the basis of fly ash and slags are analyzed. Economic aspects of fly ash and slag utilization are also evaluated. 3 refs.

  6. Bioactive Glass and Glass-Ceramic Scaffolds for Bone Tissue Engineering

    Directory of Open Access Journals (Sweden)

    Aldo R. Boccaccini

    2010-07-01

    Full Text Available Traditionally, bioactive glasses have been used to fill and restore bone defects. More recently, this category of biomaterials has become an emerging research field for bone tissue engineering applications. Here, we review and discuss current knowledge on porous bone tissue engineering scaffolds on the basis of melt-derived bioactive silicate glass compositions and relevant composite structures. Starting with an excerpt on the history of bioactive glasses, as well as on fundamental requirements for bone tissue engineering scaffolds, a detailed overview on recent developments of bioactive glass and glass-ceramic scaffolds will be given, including a summary of common fabrication methods and a discussion on the microstructural-mechanical properties of scaffolds in relation to human bone (structure-property and structure-function relationship. In addition, ion release effects of bioactive glasses concerning osteogenic and angiogenic responses are addressed. Finally, areas of future research are highlighted in this review.

  7. Are the dynamics of silicate glasses and glass-forming liquids embedded in their elastic properties?

    DEFF Research Database (Denmark)

    Smedskjær, Morten Mattrup; Mauro, John C.

    According to the elastic theory of the glass transition, the dynamics of glasses and glass-forming liquids are controlled by the evolution of shear modulus. In particular, the elastic shoving model expresses dynamics in terms of an activation energy required to shove aside the surrounding atoms......, which is determined by the shear modulus. First, we here present an in situ high-temperature Brillouin spectroscopy test of the shoving model near the glass transition of eight aluminosilicate glass-forming systems. We find that the measured viscosity data agree qualitatively with the measured...... temperature dependence of shear moduli, as predicted by the shoving model. However, the model systematically underpredicts the values of fragility. Second, we also present a thorough test of the shoving model for predicting the low temperature dynamics of an aluminosilicate glass system. This is done...

  8. Influence of foaming agents on solid thermal conductivity of foam glasses prepared from CRT panel glass

    DEFF Research Database (Denmark)

    Østergaard, Martin Bonderup; Petersen, Rasmus Rosenlund; König, Jakob

    2017-01-01

    The understanding of the thermal transport mechanism of foam glass is still lacking. The contribution of solid- and gas conduction to the total thermal conductivity remains to be reported. In many foam glasses, the solid phase consist of a mix of an amorphous and a crystalline part where foaming...... containing glass and crystalline foaming agents and amorphous samples where the foaming agents are completely dissolved in the glass structure, respectively. Results show that the samples prepared by sintering have a higher thermal conductivity than the samples prepared by melt-quenching. The thermal...... conductivities of the sintered and the melt-quenched samples represent an upper and lower limit of the solid phase thermal conductivity of foam glasses prepared with these foaming agents. The content of foaming agents dissolved in the glass structure has a major impact on the solid thermal conductivity of foam...

  9. [Quantitative determination of glass content in monazite glass-ceramics by IR technique].

    Science.gov (United States)

    He, Yong; Zhang, Bao-min

    2003-04-01

    Monazite glass-ceramics consist of both monazite and metaphoshate glass phases. The absorption bands of both phases do not overlap each other, and the absorption intensities of bands 1,275 and 616 cm-1 vary with the glass contents. The correlation coefficient between logarithmic absorbance ratio of the two bands and glass contents was r = 0.9975 and its regression equation was y = 48.356 + 25.93x. The absorbance ratio of bands 952 and 616 cm-1 also varied with different ratios of Ce2O3/La2O3 in synthetic monazites, with r = 0.9917 and a regression equation y = 0.2211 exp (0.0221x). High correlation coefficients show that the IR technique could find new application in the quantitative analysis of glass content in phosphate glass-ceramics.

  10. Relationship between thermal expansion coefficient and glass transition temperature in metallic glasses

    International Nuclear Information System (INIS)

    Kato, H.; Chen, H.-S.; Inoue, A.

    2008-01-01

    The thermal expansion coefficients of 13 metallic glasses were measured using a thermo-mechanical analyser. A unique correlation was found between the linear thermal expansion coefficient and the glass transition temperature-their product is nearly constant ∼8.24 x 10 -3 . If one assumes the Debye expression for thermal activation, the total linear thermal expansion up to glass transition temperature (T g ) is reduced to 6 x 10 -3 , nearly 25% of that at the fusion of pure metals

  11. Physical Property Investigation of Contemporary Glass lonomer and Resin Modified Glass lonomer Restorative Materials

    Science.gov (United States)

    2016-05-24

    selected physical properties of nine contemporary and recently-marketed glass-ionomer cement (GIC) and four resin-modified glass-ionomer cement {RMGIC...stainless steel molds. Testing was completed on a universal testing machine unt il failure. Knoop Hardness was obtained using fai led fracture toughness...address caries, function, biocompatibility, and minimal environmental impact. 2·3 Glass-ionomer cements were invented and developed by Wilson and Kent

  12. Effect of Ba in the glass characteristics of cesium loaded iron phosphate glasses

    International Nuclear Information System (INIS)

    Joseph, Kitheri; Asuvathraman, R.; Vasudeva Rao, P.R.

    2015-01-01

    Radioactive 137 Cs extracted from high level nuclear waste, when immobilized in a suitable matrix can be used as a γsource in medical industry. Iron phosphate glass (IPG) is one of a suitable matrix for the immobilization of 137 Cs prior to the immobilization of 137 Cs in IPG, it is essential to optimize the immobilization conditions using natural (inactive) cesium. Glass characteristics of inactive Cs loaded iron phosphate glasses were already explored in our earlier studies. However, the change in glass characteristics of 137 Cs loaded iron phosphate glass to 137 Ba loaded iron phosphate glass need to be studied before the immobilization of 137 Cs in iron phosphate glass as 137 Cs transforms to 137 Ba due to nuclear transmutation ( 137 Cs(β,γ) 137 Ba). This paper reports the studies on such a behaviour by incorporating inactive Ba in cesium loaded iron phosphate glasses. Cs and Ba loaded iron phosphate glasses were prepared by melt quench technique in air using appropriate amounts of Fe 2 O 3 , NH 4 H 2 PO 4 , Ba(OH) 2.8 H 2 O and Cs 2 CO 3 . The chemicals were added such that the glass formed possesses the batch composition of (a) 21.4 wt. % Fe 2 O 3 -45 wt. % Cs 2 O-5 wt % BaO-P 2 O 5 (henceforth referred as IP50Cs45Ba5); (b) 21.4 wt. % Fe 2 O 3 -25 wt. % Cs 2 O-25 wt % BaO-P 2 O5 (henceforth referred as IP50Cs25Ba25). The thermal expansion measurements were also carried out using a home-built quartz push-rod dilatometer. The data related to change in thermal expansion behaviour, glass forming ability, glass stability and structural changes in phosphate network due to the partial replacement of Cs with Ba will also be discussed. (author)

  13. Improving the engineering strength of heat strengthened glass

    NARCIS (Netherlands)

    Veer, F.A.; Rodichev, YM

    2016-01-01

    Although glass is increasingly used as a structural material, glass is not produced to strength standards, like steel and concrete. Of the three types of glass: annealed, heat strengthened and fully tempered, only heat strengthened glass has the properties to function as a safe structural material.

  14. Element analysis on Japanese ancient glass by PIXE method

    International Nuclear Information System (INIS)

    Koizumi, Y.; Kobayashi, K.

    2001-01-01

    The authors analyzed ancient glasses using PIXE (particle induced X-ray emission) method associated with the accelerator used for the trace analysis of environments and organisms. They examined whether the material properties of the glasses made by ancient technology have correlation with those of each era or each region both in and out of Japan. The alkali lime glasses excavated from Japanese ancient ruins are classified as soda lime glasses and potash lime glasses, and intermediate glasses containing both are also detected. As for the glasses between the late Yayoi period and the early Tumulus period in eastern Japan, glass beads were mostly classified as potash lime glasses. In the mid and late Tumulus periods, soda lime glasses and the glasses with an intermediate composition increased in addition to potash lime glasses. In the analysis of the glass beads excavated from the ruins of the late Yayoi period to the early Tumult period in Tsushima, potash lime glasses and soda lime glasses coexisted in the same period. Most of the coloring components of deep-blue system mostly found in eastern Japan were manganese and iron, and the coloring components such as blue, green, sky blue, etc. were copper. Yellow was the color expressed with lead or lead - iron. The coloring materials were common regardless of the classification of glasses based on main components. (A.O.)

  15. Study of rigidity of semiconducting vanadate glasses and its ...

    Indian Academy of Sciences (India)

    These parameters along with the coordination number of the glasses affect the glass transition temperature. The correlation between the elastic moduli and thermal properties of these samples showed that 0.25MoO3–0.25PbO–0.5V2O5 glass is the most rigid and has an applicable glass transition temperature for coating.

  16. Fracture Resistance, Surface Defects and Structural Strength of Glass

    NARCIS (Netherlands)

    Rodichev, Y.M.; Veer, F.A.

    2010-01-01

    This paper poses the theory that the fracture resistance of basic float glass is dependent on it physicochemical properties and the surface defects fonned under the float glass production, glass processing and handling at the service conditions compose the aggregate basis for structural glass

  17. On-line redox sensors in industrial glass melting tanks

    NARCIS (Netherlands)

    Laimböck, P.R.; Beerkens, R.G.C.; Schaaf, van der J.; Kieffer, J.

    2002-01-01

    The oxidation state or partial oxygen pressure (pO2) of the glass melt influences many glass melt and glass product properties such as fining and foaming behavior, radiant heat transfer, forming characteristics via (a color-dependent) cooling rate, and the glass color of the final product. For these

  18. Control of high-level radioactive waste-glass melters

    International Nuclear Information System (INIS)

    Bickford, D.F.; Coleman, C.J.

    1990-01-01

    The Defense Waste Processing Facility (DWPF) will immobilize Savannah River Site High Level Waste as a durable borosilicate glass for permanent disposal in a repository. The DWPF will be controlled based on glass composition. The following discussion is a preliminary analysis of the capability of the laboratory methods that can be used to control the glass composition, and the relationships between glass durability and glass properties important to glass melting. The glass durability and processing properties will be controlled by controlling the chemical composition of the glass. The glass composition will be controlled by control of the melter feed transferred from the Slurry Mix Evaporator (SME) to the Melter Feed Tank (MFT). During cold runs, tests will be conducted to demonstrate the chemical equivalence of glass sampled from the pour stream and glass removed from cooled canisters. In similar tests, the compositions of glass produced from slurries sampled from the SME and MFT will be compared to final product glass to determine the statistical relationships between melter feed and glass product. The total error is the combination of those associated with homogeneity in the SME or MFT, sampling, preparation of samples for analysis, instrument calibration, analysis, and the composition/property model. This study investigated the sensitivity of estimation of property data to the combination of variations from sampling through analysis. In this or a similar manner, the need for routine glass product sampling will be minimized, and glass product characteristics will be assured before the melter feed is committed to the melter

  19. Chemical durability of glasses containing radioactive fission product waste

    International Nuclear Information System (INIS)

    Mendel, J.E.; Ross, W.A.

    1974-04-01

    Measurements made to determine the chemical durability of glasses for disposal of radioactive waste are discussed. The term glass covers materials varying from true glass with only minute quantities of crystallites, such as insoluble RuO 2 , to quasi glass-ceramics which are mostly crystalline. Chemical durability requirements and Soxhlet extractor leach tests are discussed

  20. Radiophotoluminescence from silver-doped phosphate glass

    International Nuclear Information System (INIS)

    Miyamoto, Y.; Takei, Y.; Nanto, H.; Kurobori, T.; Konnai, A.; Yanagida, T.; Yoshikawa, A.; Shimotsuma, Y.; Sakakura, M.

    2011-01-01

    Glass dosimeter utilizing radiophotoluminescence (RPL) is one of accumulation type solid state dosimeters, which is based on luminescence phenomenon of silver (Ag + ions)-doped phosphate glass exposed to ionizing radiation. In this study, to clarify the emission mechanism of yellow and blue RPL peaks, optical properties of Ag + -doped glass, such as optical absorption spectrum, RPL excitation spectrum before and after X-ray irradiation as well as the lifetime of both RPL peaks are measured. From the results, we discuss the emission mechanism of yellow (peaked at 2.21 eV) and blue (peaked at 2.70 eV) RPL using a proposed energy band diagram for RPL emission and excitation in Ag + -doped phosphate glass. It is found that the radiative lifetime of blue RPL is three orders of magnitude faster than that of yellow RPL.

  1. Stress-corrosion mechanisms in silicate glasses

    International Nuclear Information System (INIS)

    Ciccotti, Matteo

    2009-01-01

    The present review is intended to revisit the advances and debates in the comprehension of the mechanisms of subcritical crack propagation in silicate glasses almost a century after its initial developments. Glass has inspired the initial insights of Griffith into the origin of brittleness and the ensuing development of modern fracture mechanics. Yet, through the decades the real nature of the fundamental mechanisms of crack propagation in glass has escaped a clear comprehension which could gather general agreement on subtle problems such as the role of plasticity, the role of the glass composition, the environmental condition at the crack tip and its relation to the complex mechanisms of corrosion and leaching. The different processes are analysed here with a special focus on their relevant space and time scales in order to question their domain of action and their contribution in both the kinetic laws and the energetic aspects.

  2. Water sensitivity and microporosity in organosilica glasses

    NARCIS (Netherlands)

    Dral, Albertine Petra

    2017-01-01

    In this dissertation the water sensitivityand microporosity of organosilica glasses are studied. The research focuses onfundamental material understanding, but stands in close relation with theindustrial application of organically bridged silicas as molecular sievingmembranes. Chapter1 presents a

  3. Effects of solar radiation on glass

    Science.gov (United States)

    Tucker, Dennis S.; Kinser, Donald L.

    1991-01-01

    The effects of solar radiation of selected glasses are reported. Optical property degradation is studied using UV-Vis spectrophotometry. Strength changes are measured using a concentric ring bend test. Direct fracture toughness measurements using an indentation test are planned.

  4. Development trends of radiophotoluminescent glass dosemeter

    International Nuclear Information System (INIS)

    Ikegami, T.

    2004-01-01

    RPL glass dosemeter has been recently recognized to have a good performance as accumulation dosemeter and has been routinely used for personal dosimetry and environmental radiation monitoring. Furthermore, its applicable field is being extending to medical radiation measurement. The history of RPL glass dosemeter is very long. It was born in USA in 1950s and after that it was improved in Japan. And it was used as personal dosemeter in 1970s. But, in those days, RPL glass dosemeter was not suitable to low dose measurement due to some handling problems. So, its use had been reduced gradually. The author has broken through any past problems, by mainly realizing the pulsed UV excitation method. In this paper, the development history, principle and features, and the development good results of the pulsed UV excitation method are summarized, including the introduction of recent RPL glass dosimetry products. (author)

  5. Radiopaque Strontium Fluoroapatite Glass-Ceramics

    Science.gov (United States)

    Höland, Wolfram; Schweiger, Marcel; Dittmer, Marc; Ritzberger, Christian

    2015-01-01

    The controlled precipitation of strontium fluoroapatite crystals was studied in four base glass compositions derived from the SiO2–Al2O3–Y2O3–SrO–Na2O–K2O/Rb2O/Cs2O–P2O5–F system. The crystal phase formation of these glasses and the main properties of the glass-ceramics, such as thermal and optical properties and radiopacity were compared with a fifth, a reference glass-ceramic. The reference glass-ceramic was characterized as Ca-fluoroapatite glass-ceramic. The four strontium fluoroapatite glass-ceramics showed the following crystal phases: (a) Sr5(PO4)3F – leucite, KAlSi2O6, (b) Sr5(PO4)3F – leucite, KAlSi2O6, and nano-sized NaSrPO4, (c) Sr5(PO4)3F – pollucite, CsAlSi2O6, and nano-sized NaSrPO4, and (d) Sr5(PO4)3F – Rb-leucite, RbAlSi2O6, and nano-sized NaSrPO4. The proof of crystal phase formation was possible by X-ray diffraction. The microstructures, which were studied using scanning electron microscopy, demonstrated a uniform distribution of the crystals in the glass matrix. The Sr-fluoroapatites were precipitated based on an internal crystallization process, and the crystals demonstrated a needle-like morphology. The study of the crystal growth of needle-like Sr-fluoroapatites gave a clear evidence of an Ostwald ripening mechanism. The formation of leucite, pollucite, and Rb-leucite was based on a surface crystallization mechanism. Therefore, a twofold crystallization mechanism was successfully applied to develop these types of glass-ceramics. The main focus of this study was the controlled development of glass-ceramics exhibiting high radiopacity in comparison to the reference glass-ceramic. This goal could be achieved with all four glass-ceramics with the preferred development of the Sr-fluoroapatite – pollucite-type glass-ceramic. In addition to this main development, it was possible to control the thermal properties. Especially the Rb-leucite containing glass-ceramic showed the highest coefficient of thermal

  6. Preparation of fullerene/glass composites

    Science.gov (United States)

    Mattes, Benjamin R.; McBranch, Duncan W.; Robinson, Jeanne M.; Koskelo, Aaron C.; Love, Steven P.

    1995-01-01

    Synthesis of fullerene/glass composites. A direct method for preparing solid solutions of C.sub.60 in silicon dioxide (SiO.sub.2) glass matrices by means of sol-gel chemistry is described. In order to produce highly concentrated fullerene-sol-gel-composites it is necessary to increase the solubility of these "guests" in a delivery solvent which is compatible with the starter sol (receiving solvent). Sonication results in aggregate disruption by treatment with high frequency sound waves, thereby accelerating the rate of hydrolysis of the alkoxide precursor, and the solution process for the C.sub.60. Depending upon the preparative procedure, C.sub.60 dispersed within the glass matrix as microcrystalline domains, or dispersed as true molecular solutions of C.sub.60 in a solid glass matrix, is generated by the present method.

  7. The Thermal Collector With Varied Glass Covers

    International Nuclear Information System (INIS)

    Luminosu, I.; Pop, N.

    2010-01-01

    The thermal collector with varied glass covers represents an innovation realized in order to build a collector able to reach the desired temperature by collecting the solar radiation from the smallest surface, with the highest efficiency. In the case of the thermal collector with variable cover glasses, the number of the glass plates covering the absorber increases together with the length of the circulation pipe for the working fluid. The thermal collector with varied glass covers compared to the conventional collector better meet user requirements because: for the same temperature increase, has the collecting area smaller; for the same collection area, realizes the highest temperature increase and has the highest efficiency. This works is addressed to researchers in the solar energy and to engineers responsible with air-conditioning systems design or industrial and agricultural products drying.

  8. Women's Career Development at the Glass Ceiling.

    Science.gov (United States)

    Inman, Pamela L.

    1998-01-01

    For women, success in shattering the glass ceiling lies not in adapting to a male workplace culture but in using career strategies such as self-knowledge, multiple mentors, integration of body and soul, and fluid, customized careers. (SK)

  9. Diversity, culture and the glass ceiling.

    Science.gov (United States)

    Wilson, Eleanor

    2014-01-01

    A reference to the term, the glass ceiling, has come to embody more than gender equality among women and men. Today the term embraces the quest of all minorities and their journey towards equality in the workplace. The purpose of this article is to bring attention to the subject of diversity, culture, and the glass ceiling. The article will discuss the history of the glass ceiling and how its broadened meaning is relevant in today's workplace. It will also provide statistics showing how diversity and culture are lacking among the top echelon of today's executives, the barriers faced by minorities as they journey towards executive leadership, and how to overcome these barriers to truly shatter the glass ceiling.

  10. SOI silicon on glass for optical MEMS

    DEFF Research Database (Denmark)

    Larsen, Kristian Pontoppidan; Ravnkilde, Jan Tue; Hansen, Ole

    2003-01-01

    and a final sealing at the interconnects can be performed using a suitable polymer. Packaged MEMS on glass are advantageous within Optical MEMS and for sensitive capacitive devices. We report on experiences with bonding SOI to Pyrex. Uniform DRIE shallow and deep etching was achieved by a combination......A newly developed fabrication method for fabrication of single crystalline Si (SCS) components on glass, utilizing Deep Reactive Ion Etching (DRIE) of a Silicon On Insulator (SOI) wafer is presented. The devices are packaged at wafer level in a glass-silicon-glass (GSG) stack by anodic bonding...... of an optimized device layout and an optimized process recipe. The behavior of the buried oxide membrane when used as an etch stop for the through-hole etch is described. No harmful buckling or fracture of the membrane is observed for an oxide thickness below 1 μm, but larger and more fragile released structures...

  11. Ceramics and glasses for radioactive waste storage

    International Nuclear Information System (INIS)

    Baudin, G.

    1984-06-01

    Borosilicate glasses are mainly choosen for the confinement of fission products; industrial plants are either in operation (AVM) or in construction. Studies of ceramics as a matrix haven't received real application [fr

  12. Studies on boro cadmium tellurite glasses

    Science.gov (United States)

    Gayathri Pavani, P.; Suresh, S.; Chandra Mouli, V.

    2011-11-01

    To investigate the modification effect of the modifier CdO on boro tellurite glass, a series of glasses with compositions (50 - x) CdO- xTeO 2-50B 2O 3 have been prepared by conventional melt quenching technique. Optical absorption, IR and Raman structural studies are carried out on the glass system. The optical absorption studies revealed that the cutoff wave length and refractive index increase while optical band gap ( Eopt) and Urbach energy decreases with increase of CdO content. The IR and Raman studies revealed that structure of glass network consists of [TeO 3]/[TeO 3+1], [TeO 4], [BO 3], [BO 4] and [Cd-Te] linkages .The compositional dependence of different physical parameters such as density, molar volume, oxygen packing density, optical basicity, have been analyzed and discussed.

  13. Celsian Glass-Ceramic Matrix Composites

    Science.gov (United States)

    Bansal, Narottam P.; Dicarlo, James A.

    1996-01-01

    Glass-ceramic matrix reinforced fiber composite materials developed for use in low dielectric applications, such as radomes. Materials strong and tough, exhibit low dielectric properties, and endure high temperatures.

  14. Radiopaque Strontium Fluoroapatite Glass-Ceramics.

    Science.gov (United States)

    Höland, Wolfram; Schweiger, Marcel; Dittmer, Marc; Ritzberger, Christian

    2015-01-01

    The controlled precipitation of strontium fluoroapatite crystals was studied in four base glass compositions derived from the SiO2-Al2O3-Y2O3-SrO-Na2O-K2O/Rb2O/Cs2O-P2O5-F system. The crystal phase formation of these glasses and the main properties of the glass-ceramics, such as thermal and optical properties and radiopacity were compared with a fifth, a reference glass-ceramic. The reference glass-ceramic was characterized as Ca-fluoroapatite glass-ceramic. The four strontium fluoroapatite glass-ceramics showed the following crystal phases: (a) Sr5(PO4)3F - leucite, KAlSi2O6, (b) Sr5(PO4)3F - leucite, KAlSi2O6, and nano-sized NaSrPO4, (c) Sr5(PO4)3F - pollucite, CsAlSi2O6, and nano-sized NaSrPO4, and (d) Sr5(PO4)3F - Rb-leucite, RbAlSi2O6, and nano-sized NaSrPO4. The proof of crystal phase formation was possible by X-ray diffraction. The microstructures, which were studied using scanning electron microscopy, demonstrated a uniform distribution of the crystals in the glass matrix. The Sr-fluoroapatites were precipitated based on an internal crystallization process, and the crystals demonstrated a needle-like morphology. The study of the crystal growth of needle-like Sr-fluoroapatites gave a clear evidence of an Ostwald ripening mechanism. The formation of leucite, pollucite, and Rb-leucite was based on a surface crystallization mechanism. Therefore, a twofold crystallization mechanism was successfully applied to develop these types of glass-ceramics. The main focus of this study was the controlled development of glass-ceramics exhibiting high radiopacity in comparison to the reference glass-ceramic. This goal could be achieved with all four glass-ceramics with the preferred development of the Sr-fluoroapatite - pollucite-type glass-ceramic. In addition to this main development, it was possible to control the thermal properties. Especially the Rb-leucite containing glass-ceramic showed the highest coefficient of thermal expansion (CTE). These

  15. Towards Luminescence Dating Of Mosaic Glass

    Science.gov (United States)

    Galli, A.; Martini, M.; Sibila, E.; Villa, I.

    The possibility of dating archaeological glass by means of luminescent techniques has been investigated in recent years, despite the difficulties of this application, mainly linked to the amorphous structure of the material. We focused in particular on mosaic glass, after the encouraging results obtained on byzantine and medieval samples. Further studies were devoted to the comprehension of the luminescent mechanisms in silica glasses, and to the investigation of the relationships between luminescence, colouring or opacifier ions and crystalline phase of the vitreous matrix. The results of a study on the dosimetric characteristics of thermoluminescence (TL) and Optically Stimulated Luminescence (OSL) of a few medieval blue-green mosaic glasses from the San Lorenzo church (Milan) are presented, and the experimental protocols established to identify their suitability for dating are discussed.

  16. Vibrational anomalies and marginal stability of glasses

    KAUST Repository

    Marruzzo, Alessia; Kö hler, Stephan; Fratalocchi, Andrea; Ruocco, Giancarlo; Schirmacher, Walter

    2013-01-01

    The experimentally measured vibrational spectrum of glasses strongly deviates from that expected in Debye's elasticity theory: The density of states deviates from Debye's ω2 law ("boson peak"), the sound velocity shows a negative dispersion

  17. Improvement of database on glass dissolution

    International Nuclear Information System (INIS)

    Hayashi, Maki; Sasamoto, Hiroshi; Yoshikawa, Hideki

    2008-03-01

    In geological disposal system, high-level radioactive waste (HLW) glass is expected to retain radionuclide for the long term as the first barrier to prevent radionuclide release. The advancement of its performance assessment technology leads to the reliability improvement of the safety assessment of entire geological disposal system. For this purpose, phenomenological studies for improvement of scientific understanding of dissolution/alteration mechanisms, and development of robust dissolution/alteration model based on the study outcomes are indispensable. The database on glass dissolution has been developed for supporting these studies. This report describes improvement of the prototype glass database. Also, this report gives an example of the application of the database for reliability assessment of glass dissolution model. (author)

  18. Nonlinear Properties of Soft Glass Waveguides

    DEFF Research Database (Denmark)

    Steffensen, Henrik

    -infrared applications and the THz applications. In the mid-infrared, it is investigated whether soft glasses are a suitable candidate for supercontinuum generation (SCG). A few commercially available fluoride fibers are tested for their zero dispersion wavelength (ZDW), a key property when determining the possibility......This thesis builds around the investigation into using soft glass materials for midinfrared and THz applications. Soft glasses is a term that cov ers a wide range of chemical compositions where many are yet to be fully investigated. The work in this thesis is separated in two parts, the mid...... of SCG in a fiber. A group of soft glasses, namely the chalcogenides, are known to display two photon absorption (TPA) which could potentially limit the SCG when this is initiated within the frequency range where this nonlinear process occur. An analytic model is presented to estimate the soliton self...

  19. Measuring Mechanical Properties Of Optical Glasses

    Science.gov (United States)

    Tucker, Dennis S.; Nichols, Ronald L.

    1989-01-01

    Report discusses mechanical tests measuring parameters of strength and fracture mechanics of optical glasses. To obtain required tables of mechanical properties of each glass of interest, both initial-strength and delayed-fracture techniques used. Modulus of rupture measured by well-known four-point bending method. Initial bending strength measured by lesser-known double-ring method, in which disk of glass supported on one face near edge by larger ring and pressed on its other face by smaller concentric ring. Method maximizes stress near center, making it more likely specimen fractures there, and thereby suppresses edge effects. Data from tests used to predict reliabilities and lifetimes of glass optical components of several proposed spaceborne instruments.

  20. Origin of Inhomogeneity in Glass Melts

    DEFF Research Database (Denmark)

    Jensen, Martin; Keding, Ralf; Yue, Yuanzheng

    The homogeneity of a glass plays a crucial role in many applications as the inhomogeneities can provide local changes in mechanical properties, optical properties, and thermal expansion coefficient. Homogeneity is not a single property of the glass, instead, it consists of several factors...... such as bubbles, striae, trace element concentration, undissolved species, and crystallised species. As it is not possible to address all the factors in a single study, this work focuses on one of the major factors: chemical striae. Up to now, the quantification of chemical striae in glasses, particularly......, in less transparent glasses, has been a challenge due to the lack of an applicable method. In this study, we have established a simple and accurate method for quantifying the extent of the striae, which is based on the scanning and picture processing through the Fourier transformation. By performing...