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Sample records for soluble phosphate glass

  1. Properties and solubility of chrome in iron alumina phosphate glasses containing high level nuclear waste

    International Nuclear Information System (INIS)

    Huang, W.; Day, D.E.; Ray, C.S.; Kim, C.W.; Reis, S.T.D.

    2004-01-01

    Chemical durability, glass formation tendency, and other properties of iron alumina phosphate glasses containing 70 wt% of a simulated high level nuclear waste (HLW), doped with different amounts of Cr 2 O 3 , have been investigated. All of the iron alumina phosphate glasses had an outstanding chemical durability as measured by their small dissolution rate (1 . 10 -9 g/(cm 2 . min)) in deionized water at 90 C for 128 d, their low normalized mass release as determined by the product consistency test (PCT) and a barely measurable corrosion rate of 2 . d) after 7 d at 200 C by the vapor hydration test (VHT). The solubility limit for Cr 2 O 3 in the iron phosphate melts was estimated at 4.1 wt%, but all of the as-annealed melts contained a few percent of crystalline Cr 2 O 3 that had no apparent effect on the chemical durability. The chemical durability was unchanged after deliberate crystallization, 48 h at 650 C. These iron phosphate waste forms, with a waste loading of at least 70 wt%, can be readily melted in commercial refractory crucibles at 1250 C for 2 to 4 h, are resistant to crystallization, meet all current US Department of Energy requirements for chemical durability, and have a solubility limit for Cr 2 O 3 which is at least three times larger than that for borosilicate glasses. (orig.)

  2. Structure-solubility relationships in fluoride-containing phosphate based bioactive glasses

    Science.gov (United States)

    Shaharyar, Yaqoot

    The dissolution of fluoride-containing bioactive glasses critically affects their biomedical applications. Most commercial fluoride-releasing bioactive glasses have been designed in the soda-lime-silica system. However, their relatively slow chemical dissolution and the adverse effect of fluoride on their bioactivity are stimulating the study of novel biodegradable materials with higher bioactivity, such as biodegradable phosphate-based bioactive glasses, which can be a viable alternative for applications where a fast release of active ions is sought. In order to design new biomaterials with controlled degradability and high bioactivity, it is essential to understand the connection between chemical composition, molecular structure, and solubility in physiological fluids.Accordingly, in this work we have combined the strengths of various experimental techniques with Molecular Dynamics (MD) simulations, to elucidate the impact of fluoride ions on the structure and chemical dissolution of bioactive phosphate glasses in the system: 10Na2O - (45-x) CaO - 45P2O5 - xCaF2, where x varies between 0 -- 10 mol.%. NMR and MD data reveal that the medium-range atomic-scale structure of thse glasses is dominated by Q2 phosphate units followed by Q1 units, and the MD simulations further show that fluoride tends to associate with network modifier cations to form alkali/alkaline-earth rich ionic aggregates. On a macroscopic scale, we find that incorporating fluoride in phosphate glasses does not affect the rate of apatite formation on the glass surface in simulated body fluid (SBF). However, fluoride has a marked favorable impact on the glass dissolution in deionized water. Similarly, fluoride incorporation in the glasses results in significant weight gain due to adsorption of water (in the form of OH ions). These macroscopic trends are discussed on the basis of the F effect on the atomistic structure of the glasses, such as the F-induced phosphate network re-polymerization, in a

  3. 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

  4. 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.

  5. Investigation of lead-iron-phosphate glass for SRP waste

    International Nuclear Information System (INIS)

    Jantzen, C.M.

    1986-10-01

    The search for a host solid for the immobilization of nuclear waste has focused on various vitreous waste forms. Recently, lead-iron-phosphate (LIP) glasses have been proposed for solidification of all types of HLLW. Investigation of this glass for vitrification of SRP waste demonstrated that the phosphate glass is incompatible with the current borosilicate glass technology. The durability of LIP glasses in deionized water was comparable to current borosilicate waste glass formulations, and the LIP glass has a low melt temperature. However, many of the defense waste constituents have low solubility in the phosphate melt, producing an inhomogeneous product. Also, the LIP melt is highly corrosive which prevents the use of current melter materials, in particular Inconel 690, and thus requires more exotic materials of construction such as platinum

  6. In vitro solubility and bioactivity of Sr and Mg co-doped calcium phosphate glass-ceramics derived from different heat-treatment temperatures

    International Nuclear Information System (INIS)

    Cai Shu; Li Jianxin; Xu Guohua; Li, Xudong; Ye Xiaojian; Jiang Wei

    2011-01-01

    Highlights: ► Porous glass ceramics were prepared by controlled heat treatment process. ► A fast release of Mg ions has a great influence on the Ca/P ratio of the deposits. ► The chemical stability of the deposited apatite directly affects cell behavior. ► The glass ceramics heat-treated at 760 °C and 780 °C show less glass. ► The degradation rates are both compatible with cell growth and differentiation. - Abstract: CaO–P 2 O 5 –Na 2 O–SrO–MgO glass–ceramic system was prepared by controlled heat treatment process. Solubility and bioactivity of glass-ceramics were measured and evaluated in simulated body fluid (SBF) and cell culture medium respectively. The dissolution behavior of these glass-ceramics strongly depends on the amount and microstructure of the crystals precipitated by sintering treatment. Concerning the bioactivity, the onset of the apatite formation on the glass–ceramic system was directly dependent on the amount of bioactive glass amount which can be controlled using different temperatures of heat treatment. After immersing glass–ceramic in SBF, Mg ion as one of system composition can be released from residual glass and provides a high impact on the Ca/P ratio and chemical stability of the deposited apatite layer that directly affects cell attachment and proliferation in in vitro cell culture system. The glass ceramics heat-treated at 760 °C and 780 °C show less glass amount, and their degradation rates are both compatible with cell growth and differentiation.

  7. 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 ...

  8. 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

  9. 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)

  10. 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.

  11. Investigation of alumino-phosphate glasses for iodine conditioning

    International Nuclear Information System (INIS)

    Lemesle, T.

    2013-01-01

    Iodine 129 is a long-lived intermediate level radioactive waste, which is currently managed by isotopic dilution. In view of an alternative management by geological disposal, we aimed at developing phosphate glasses of the AgI-Ag 2 O-P 2 O 5 -Al 2 O 3 system, elaborated at low temperature and without iodine volatilization. Alumina is expected to induce crosslinking of the phosphate network and thus to improve the thermal and chemical properties. To define a glass composition that meets the specifications, we varied the level of iodine, the Ag 2 O/P 2 O 5 ratio and alumina content. For 1 g.cm -3 of iodine, SEM-EDS observations indicate that alumina solubility is limited to 0.5% mol., independently of Ag 2 O/P 2 O 5 ratio. The structural study by 31 P, 27 Al and 109 Ag MAS NMR, shows that aluminum adopts an octahedral coordination that effectively contributes to the crosslinking of the glassy network and iodine is incorporated without clustering. 31 P- 27 Al NMR correlations confirmed the presence of an alumino-phosphate network, and 31 P- 31 P correlations indicate that iodine does not change the connectivity of the glass network. The glass composition 28,8AgI-44,2Ag 2 O-26,5P 2 O 5 -0,5Al 2 O 3 presents the best compromise between the level of incorporation of iodine and the chemical durability, has a glass transition temperature of 123 C and an initial alteration rate in pure water at 50 C of 6 g.m -2 .d -1 . The long-term behavior of this glass is controlled by a post-alteration structure based on pyrophosphate, which holds nearly 80% of the initial iodine. (author) [fr

  12. Monte Carlo Simulations of Phosphate Polyhedron Connectivity in Glasses

    Energy Technology Data Exchange (ETDEWEB)

    ALAM,TODD M.

    1999-12-21

    Monte Carlo simulations of phosphate tetrahedron connectivity distributions in alkali and alkaline earth phosphate glasses are reported. By utilizing a discrete bond model, the distribution of next-nearest neighbor connectivities between phosphate polyhedron for random, alternating and clustering bonding scenarios was evaluated as a function of the relative bond energy difference. The simulated distributions are compared to experimentally observed connectivities reported for solid-state two-dimensional exchange and double-quantum NMR experiments of phosphate glasses. These Monte Carlo simulations demonstrate that the polyhedron connectivity is best described by a random distribution in lithium phosphate and calcium phosphate glasses.

  13. Ultraviolet optical absorptions of semiconducting copper phosphate glasses

    Science.gov (United States)

    Bae, Byeong-Soo; Weinberg, Michael C.

    1993-01-01

    Results are presented of a quantitative investigation of the change in UV optical absorption in semiconducting copper phosphate glasses with batch compositions of 40, 50, and 55 percent CuO, as a function of the Cu(2+)/Cu(total) ratio in the glasses for each glass composition. It was found that optical energy gap, E(opt), of copper phosphate glass is a function of both glass composition and Cu(2+)/Cu(total) ratio in the glass. E(opt) increases as the CuO content for fixed Cu(2+)/Cu(total) ratio and the Cu(2+)/Cu(total) ratio for fixed glass composition are reduced.

  14. Solubility of actinides and surrogates in nuclear glasses

    International Nuclear Information System (INIS)

    Lopez, Ch.

    2003-01-01

    The nuclear wastes are currently incorporated in borosilicate glass matrices. The resulting glass must be perfectly homogeneous. The work discussed here is a study of actinide (thorium and plutonium) solubility in borosilicate glass, undertaken to assess the extent of actinide solubility in the glass and to understand the mechanisms controlling actinide solubilization. Glass specimens containing; actinide surrogates were used to prepare and optimize the fabrication of radioactive glass samples. These preliminary studies revealed that actinide Surrogates solubility in the glass was enhanced by controlling the processing temperature, the dissolution kinetic of the surrogate precursors, the glass composition and the oxidizing versus reducing conditions. The actinide solubility was investigated in the borosilicate glass. The evolution of thorium solubility in borosilicate glass was determined for temperatures ranging from 1200 deg C to 1400 deg C.Borosilicate glass specimens containing plutonium were fabricated. The experimental result showed that the plutonium solubility limit ranged from 1 to 2.5 wt% PuO 2 at 1200 deg C. A structural approach based on the determination of the local structure around actinides and their surrogates by EXAFS spectroscopy was used to determine their structural role in the glass and the nature of their bonding with the vitreous network. This approach revealed a correlation between the length of these bonds and the solubility of the actinides and their surrogates. (author)

  15. Radiochemical investigations on the solubility of molybdatophosphate in phosphate determination

    International Nuclear Information System (INIS)

    Noack, S.

    1975-01-01

    The solubility of various molybdatophosphates was determined under the conditions of a gravimetric phosphate determination by radiochemical means by labelling PO 4 3- with P-32. Starting with various conditions for phosphate determination via the molybdatophosphate of quinoline, 8-hydroxyquinoline, dimorpholino ethane, N,N,N',N'-tetrakis-β-hydroxypropyl ethylene diamine and N,N,N',N'-tetrakis-β-hydroxybutyl ethylene diamine, a general working rule was developed to determine the solubility. Taking the example of quinoline molybdatophosphates, a series of influencing factors - work, concentration and measuring parameters - were investigated in order to be able to limit the reliability region of the gravimetric phosphate determination. Depending on the conditions, the measured solubilities were between 10 -10 and 10 -6 Mol/l, the corresponding degrees of precipitation between 99.0 and 99.9999%. Apparent solubility products were calculated for the different molybdatophosphates using computer programmes especially developed for this purpose. (orig./RB) [de

  16. A comparative property investigation of lithium phosphate glass

    Indian Academy of Sciences (India)

    The present study addresses the application of microwave (MW) energy for melting lithium phosphate glass. Acomparative analysis of the properties is presented with glasses melted in conventional resistance heating adopting standardmethods of characterization. The density of the glass was found less in MW heating.

  17. Micro-Raman spectroscopy studies of the phase separation mechanisms of transition-metal phosphate glasses

    International Nuclear Information System (INIS)

    Mazali, Italo Odone; Alves, Oswaldo Luiz; Gimenez, Iara de Fatima

    2009-01-01

    Glass-ceramics are prepared by controlled separation of crystal phases in glasses, leading to uniform and dense grain structures. On the other hand, chemical leaching of soluble crystal phases yields porous glass-ceramics with important applications. Here, glass/ceramic interfaces of niobo-, vanado- and titano-phosphate glasses were studied by micro-Raman spectroscopy, whose spatial resolution revealed the multiphase structures. Phase-separation mechanisms were also determined by this technique, revealing that interface composition remained unchanged as the crystallization front advanced for niobo- and vanadophosphate glasses (interface-controlled crystallization). For titanophosphate glasses, phase composition changed continuously with time up to the equilibrium composition, indicating a spinodal-type phase separation. (author)

  18. The electrical properties of semiconducting vanadium phosphate glasses

    International Nuclear Information System (INIS)

    Moridi, G.R.; Hogarth, C.A.; Hekmat Shooar, N.H.

    1984-01-01

    Vanadium phosphate glasses are a group of oxide glasses which show the semiconducting behaviour. In contrast to the conventional glasses, the conduction mechanism in these glasses is electronic, rather than being ionic. Since 1954, when the first paper appeared on the semiconducting properties of these glasses, much work has been carried out on transition-metal-oxide glasses in general, and vanadium phosphate glasses in particular. The mechanism of conduction is basicaly due to the transport of electrons between the transition-metal ions in different valency states. In the present paper, we have reviewed the previous works on the electrical characteristics of P 2 O 5 -V 2 O 5 glasses and also discussed the current theoretical ideas relevant for the interpretation of the experimental data

  19. Iron phosphate glasses: Bulk properties and atomic scale structure

    Energy Technology Data Exchange (ETDEWEB)

    Joseph, Kitheri; Stennett, Martin C.; Hyatt, Neil C.; Asuvathraman, R.; Dube, Charu L.; Gandy, Amy S.; Govindan Kutty, K. V.; Jolley, Kenny; Vasudeva Rao, P. R.; Smith, Roger

    2017-10-01

    Bulk properties such as glass transition temperature, density and thermal expansion of iron phosphate glass compositions, with replacement of Cs by Ba, are investigated as a surrogate for the transmutation of 137Cs to 137Ba, relevant to the immobilisation of Cs in glass. These studies are required to establish the appropriate incorporation rate of 137Cs in iron phosphate glass. Density and glass transition temperature increases with the addition of BaO indicating the shrinkage and reticulation of the iron phosphate glass network. The average thermal expansion coefficient reduces from 19.8 × 10-6 K-1 to 13.4 × 10-6 K-1, when 25 wt. % of Cs2O was replaced by 25 wt. % of BaO in caesium loaded iron phosphate glass. In addition to the above bulk properties, the role of Ba as a network modifier in the structure of iron phosphate glass is examined using various spectroscopic techniques. The FeII content and average coordination number of iron in the glass network was estimated using Mössbauer spectroscopy. The FeII content in the un-doped iron phosphate glass and barium doped iron phosphate glasses was 20, 21 and 22 ± 1% respectively and the average Fe coordination varied from 5.3 ± 0.2 to 5.7 ± 0.2 with increasing Ba content. The atomic scale structure was further probed by Fe K-edge X-ray absorption spectroscopy. The average coordination number provided by extended X-ray absorption fine structure spectroscopy and X-ray absorption near edge structure was in good agreement with that given by the Mössbauer data.

  20. Characterization of iron phosphate glasses prepared by microwave heating

    International Nuclear Information System (INIS)

    Almeida, Fabio Jesus Moreira de

    2006-01-01

    Phosphate glasses have been investigated since the fifties, because they are relatively easy to prepare, have low melting temperatures (1000 deg C - 1200 deg C and low glass transition. However, these glasses were very sensitive to humidity, showing a very low chemical durability. Iron phosphate glasses have been prepared by melting inorganic precursors in conventional electric furnaces and induction furnaces. By adding iron, phosphate glasses became chemical resistant and were thought to be used as nuclear waste forms or mechanical resistance fibers. The use of microwaves has been investigated because it makes possible a fast and homogeneous heating of the materials. Microwave promotes the self-heating of the material by the interaction of the external electromagnetic field with the molecules and ions of the material. Niobium phosphate glasses was also produced already through the heating of precursors in microwave ovens. Other glasses containing iron in theirs structure was produced by conventional furnaces and they had your structures analyzed. But even so, it was not still published synthesis of iron phosphate glasses starting from the melting of precursors materials in microwave ovens. In the present work mixtures of (NH 4 ) 2 HPO 4 and Fe 3 O 4 or (NH 4 ) 2 HPO 4 and Fe 2 O 3 were exposed to microwave energy with electromagnetic waves of 2,45 GHz. It was proposed that the absorption of this radiation for the material causes the heating from room temperature to melting temperature. The obtained iron phosphate glasses was analyzed by X-ray diffraction, Moessbauer spectroscopy, and Differential Thermal Analysis. Iron phosphate glasses were also produced in electrical furnaces for comparison. (author)

  1. Characterization of iron phosphate glasses prepared by microwave heating

    International Nuclear Information System (INIS)

    Almeida, Fabio Jesus Moreira de

    2006-01-01

    Phosphate glasses have been investigated since the fifties, because they are relatively easy to prepare, have low melting temperatures (1000 deg C - 1200 deg C), and low glass transition. However, these glasses were very sensitive to humidity, showing a very low chemical durability. Iron phosphate glasses have been prepared by melting inorganic precursors in conventional electric furnaces and induction furnaces. By adding iron, phosphate glasses became chemical resistant and were thought to be used as nuclear waste forms or mechanical resistance fibers. The use of microwaves has been investigated because it makes possible a fast and homogeneous heating of the materials. Microwave promotes the self-heating of the material by the interaction of the external electromagnetic field with the molecules and ions of the material. Niobium phosphate glasses was also produced already through the heating of precursors in microwave ovens. Other glasses containing iron in theirs structure was produced by conventional furnaces and they had your structures analyzed. But even so, it was not still published synthesis of iron phosphate glasses starting from the melting of precursors materials in microwave ovens. In the present work mixtures of (NH 4 ) 2 HPO 4 and Fe 3 O 4 or (NH 4 ) 2 HPO 4 and Fe 2 O 3 were exposed to microwave energy with electromagnetic waves of 2,45 GHz. It was proposed that the absorption of this radiation for the material causes the heating from room temperature to melting temperature. The obtained iron phosphate glasses was analyzed by X-ray diffraction, Moessbauer spectroscopy, and Differential Thermal Analysis. Iron phosphate glasses were also produced in electrical furnaces for comparison. (author)

  2. Magnesium-phosphate-glass cements with ceramic-type properties

    Science.gov (United States)

    Sugama, T.; Kukacka, L.E.

    1982-09-23

    Rapid setting magnesium phosphate (Mg glass) cementitious materials consisting of magnesium phosphate cement paste, polyborax and water-saturated aggregate, exhibits rapid setting and high early strength characteristics. The magnesium glass cement is prepared from a cation-leachable powder and a bivalent metallic ion-accepting liquid such as an aqueous solution of diammonium phosphate and ammonium polyphosphate. The cation-leachable powder includes a mixture of two different magnesium oxide powders processed and sized differently which when mixed with the bivalent metallic ion-accepting liquid provides the magnesium glass cement consisting primarily of magnesium ortho phosphate tetrahydrate, with magnesium hydroxide and magnesium ammonium phosphate hexahydrate also present. The polyborax serves as a set-retarder. The resulting magnesium mono- and polyphosphate cements are particularly suitable for use as a cementing matrix in rapid repair systems for deteriorated concrete structures as well as construction materials and surface coatings for fireproof structures.

  3. Magnesium phosphate glass cements with ceramic-type properties

    Science.gov (United States)

    Sugama, Toshifumi; Kukacka, Lawrence E.

    1984-03-13

    Rapid setting magnesium phosphate (Mg glass) cementitious materials consisting of magnesium phosphate cement paste, polyborax and water-saturated aggregate exhibiting rapid setting and high early strength characteristics. The magnesium glass cement is prepared from a cation-leachable powder and a bivalent metallic ion-accepting liquid such as an aqueous solution of diammonium phosphate and ammonium polyphosphate. The cation-leachable powder includes a mixture of two different magnesium oxide powders processed and sized differently which when mixed with the bivalent metallic ion-accepting liquid provides the magnesium glass cement consisting primarily of magnesium ortho phosphate tetrahydrate, with magnesium hydroxide and magnesium ammonium phosphate hexahydrate also present. The polyborax serves as a set-retarder. The resulting magnesium mono- and polyphosphate cements are particularly suitable for use as a cementing matrix in rapid repair systems for deteriorated concrete structures as well as construction materials and surface coatings for fireproof structures.

  4. Femtosecond laser writing of waveguides in zinc phosphate glasses [Invited

    NARCIS (Netherlands)

    Fletcher, L.B.; Witcher, J.J.; Troy, N.; Reis, S.T.; Brow, R.K.; Martinez Vazquez, R.; Osellame, R.; Krol, D.M.

    2011-01-01

    We have studied the relationship between the initial glass composition and the structural changes associated with laser-induced refractive index modification in a series of Er-Yb doped and undoped zinc phosphate glasses. White light microscopy and waveguide experiments are used together with Raman

  5. Characterization of Fe 3 + -doped silver phosphate glasses

    Indian Academy of Sciences (India)

    The relationship among the composition, structure and selected properties for five series of silver phosphate glasses containing 0, 5, 10, 15 and 20wt% Fe 2 O 3 has been investigated. The synthesized glasses have been characterized using different experimental techniques. X-ray diffraction studies revealed that the ...

  6. 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)

  7. Structure and properties of calcium iron phosphate glasses

    Energy Technology Data Exchange (ETDEWEB)

    Qian, Bin [School of Science, Southwest University of Science and Technology, Mianyang 621010 (China); Liang, Xiaofeng, E-mail: xfliangswust@gmail.com [Analytical and Testing Center, Southwest University of Science and Technology, Mianyang 621010 (China); School of Materials Science and Engineering, Southwest University of Science and Technology, Mianyang 621010 (China); Wang, Cuiling; Yang, Shiyuan [School of Materials Science and Engineering, Southwest University of Science and Technology, Mianyang 621010 (China)

    2013-11-15

    The structural properties of xCaO–(100 − x) (0.4Fe{sub 2}O{sub 3}–0.6P{sub 2}O{sub 5}) (x = 0, 10, 20, 30, 40, 50 mol%) glasses have been investigated by XRD, DTA, IR and Raman spectroscopy. XRD analysis has confirmed that the majority of samples are X-ray amorphous, and EDS analysis indicates that the glass matrix can accommodate ≈30 mol% CaO. IR and Raman spectra show that the glass structure consists predominantly of pyrophosphate (Q{sup 1}) units. IR spectra indicate that the phosphate network is depolymerized with the addition of CaO content. The density and glass transition temperature (T{sub g}) increase with increasing CaO content for the glasses. This behavior indicates that the addition of CaO improves the strength of the cross-links between the phosphate chains of the glass.

  8. 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)

  9. Modelling aqueous corrosion of nuclear waste phosphate glass

    Energy Technology Data Exchange (ETDEWEB)

    Poluektov, Pavel P.; Schmidt, Olga V.; Kascheev, Vladimir A. [Bochvar All-Russian Scientific Research Institute for Inorganic Materials (VNIINM), Moscow (Russian Federation); Ojovan, Michael I., E-mail: m.ojovan@sheffield.ac.uk [Immobilisation Science Laboratory, Department of Materials Science and Engineering, University of Sheffield, Mappin Street, Sheffield, S1 3JD (United Kingdom)

    2017-02-15

    A model is presented on nuclear sodium alumina phosphate (NAP) glass aqueous corrosion accounting for dissolution of radioactive glass and formation of corrosion products surface layer on the glass contacting ground water of a disposal environment. Modelling is used to process available experimental data demonstrating the generic inhibiting role of corrosion products on the NAP glass surface. - Highlights: • The radionuclides yield is determined by the transport from the glass through the surface corrosion layer. • Formation of the surface layer is due to the dissolution of the glass network and the formation of insoluble compounds. • The model proposed accounts for glass dissolution, formation of corrosion layer, specie diffusion and chemical reactions. • Analytical solutions are found for corrosion layer growth rate and glass components component leaching rates.

  10. Highly Doped Phosphate Glass Fibers for Compact Lasers and Amplifiers: A Review

    Directory of Open Access Journals (Sweden)

    Nadia Giovanna Boetti

    2017-12-01

    Full Text Available In recent years, the exploitation of compact laser sources and amplifiers in fiber form has found extensive applications in industrial and scientific fields. The fiber format offers compactness, high beam quality through single-mode regime and excellent heat dissipation, thus leading to high laser reliability and long-term stability. The realization of devices based on this technology requires an active medium with high optical gain over a short length to increase efficiency while mitigating nonlinear optical effects. Multicomponent phosphate glasses meet these requirements thanks to the high solubility of rare-earth ions in their glass matrix, alongside with high emission cross-sections, chemical stability and high optical damage threshold. In this paper, we review recent advances in the field thanks to the combination of highly-doped phosphate glasses and innovative fiber drawing techniques. We also present the main performance achievements and outlook both in continuous wave (CW and pulsed mode regimes.

  11. Solubility effects in waste-glass/demineralized-water systems

    International Nuclear Information System (INIS)

    Fullam, H.T.

    1981-06-01

    Aqueous systems involving demineralized water and four glass compositions (including standins for actinides and fission products) at temperatures of up to 150 0 C were studied. Two methods were used to measure the solubility of glass components in demineralized water. One method involved approaching equilibrium from subsaturation, while the second method involved approaching equilibrium from supersaturation. The aqueous solutions were analyzed by induction-coupled plasma spectrometry (ICP). Uranium was determined using a Scintrex U-A3 uranium analyzer and zinc and cesium were determined by atomic absorption. The system that results when a waste glass is contacted with demineralized water is a complex one. The two methods used to determine the solubility limits gave very different results, with the supersaturation method yielding much higher solution concentrations than the subsaturation method for most of the elements present in the waste glasses. The results show that it is impossible to assign solubility limits to the various glass components without thoroughly describing the glass-water systems. This includes not only defining the glass type and solution temperature, but also the glass surface area-to-water volume ratio (S/V) of the system and the complete thermal history of the system. 21 figures, 22 tables

  12. Structure and Degradation Behaviour of Calcium Phosphate Glasses

    International Nuclear Information System (INIS)

    Silva, A M B; Correia, R N; Fernandes, M H V; Oliveira, J M M

    2011-01-01

    Some studies have shown a relationship between glass structure and in vitro mineralization, generally associated with the rate of glass degradation, nature of released ions and subsequent Ca-P precipitation on glass surfaces when immersed in a Simulated Body Fluid (SBF). The knowledge of the ionic species distribution in glasses and of the involved bond strengths can be used to assess the in vitro behaviour of a glass. The role of ions such as silicon or titanium is of major importance for the development of new compositions and also for the control of glass degradation behaviour. A comparative study with two calcium phosphate glasses series was performed: Both glasses series - one with Si and another with Ti - include P 2 O 5 and alkaline earth ions in their compositions. Surface reactivity of glasses from the SiO 2 -containing system have been studied in SBF showing the precipitation of a Ca-P surface layer that increases with increasing MgO/CaO ratio. In glasses from the TiO 2 -containing series it is shown that the increase of TiO 2 contributes for the stabilization of the glass network thus allowing the control of their degradation rate when immersed in SBF. The relationship between structural features of these calcium-phosphate glasses and their degradation behaviour in SBF is discussed in terms of the structural role of Si and Ti ions. It is concluded that glasses with less interconnected species favour the Ca-P surface precipitation. The understanding of this relationship in synthetic physiological fluids is expected to allow the tailoring of glass degradation rates in complex biological systems.

  13. PLUTONIUM SOLUBILITY IN HIGH-LEVEL WASTE ALKALI BOROSILICATE GLASS

    Energy Technology Data Exchange (ETDEWEB)

    Marra, J.; Crawford, C.; Fox, K.; Bibler, N.

    2011-01-04

    The solubility of plutonium in a Sludge Batch 6 (SB6) reference glass and the effect of incorporation of Pu in the glass on specific glass properties were evaluated. A Pu loading of 1 wt % in glass was studied. Prior to actual plutonium glass testing, surrogate testing (using Hf as a surrogate for Pu) was conducted to evaluate the homogeneity of significant quantities of Hf (Pu) in the glass, determine the most appropriate methods to evaluate homogeneity for Pu glass testing, and to evaluate the impact of Hf loading in the glass on select glass properties. Surrogate testing was conducted using Hf to represent between 0 and 1 wt % Pu in glass on an equivalent molar basis. A Pu loading of 1 wt % in glass translated to {approx}18 kg Pu per Defense Waste Processing Facility (DWPF) canister, or about 10X the current allowed limit per the Waste Acceptance Product Specifications (2500 g/m{sup 3} of glass or about 1700 g/canister) and about 30X the current allowable concentration based on the fissile material concentration limit referenced in the Yucca Mountain Project License Application (897 g/m{sup 3}3 of glass or about 600 g Pu/canister). Based on historical process throughput data, this level was considered to represent a reasonable upper bound for Pu loading based on the ability to provide Pu containing feed to the DWPF. The task elements included evaluating the distribution of Pu in the glass (e.g. homogeneity), evaluating crystallization within the glass, evaluating select glass properties (with surrogates), and evaluating durability using the Product Consistency Test -- Method A (PCT-A). The behavior of Pu in the melter was evaluated using paper studies and corresponding analyses of DWPF melter pour samples.The results of the testing indicated that at 1 wt % Pu in the glass, the Pu was homogeneously distributed and did not result in any formation of plutonium-containing crystalline phases as long as the glass was prepared under 'well-mixed' conditions

  14. Plutonium Solubility In High-Level Waste Alkali Borosilicate Glass

    International Nuclear Information System (INIS)

    Marra, J.; Crawford, C.; Fox, K.; Bibler, N.

    2011-01-01

    The solubility of plutonium in a Sludge Batch 6 (SB6) reference glass and the effect of incorporation of Pu in the glass on specific glass properties were evaluated. A Pu loading of 1 wt % in glass was studied. Prior to actual plutonium glass testing, surrogate testing (using Hf as a surrogate for Pu) was conducted to evaluate the homogeneity of significant quantities of Hf (Pu) in the glass, determine the most appropriate methods to evaluate homogeneity for Pu glass testing, and to evaluate the impact of Hf loading in the glass on select glass properties. Surrogate testing was conducted using Hf to represent between 0 and 1 wt % Pu in glass on an equivalent molar basis. A Pu loading of 1 wt % in glass translated to ∼18 kg Pu per Defense Waste Processing Facility (DWPF) canister, or about 10X the current allowed limit per the Waste Acceptance Product Specifications (2500 g/m 3 of glass or about 1700 g/canister) and about 30X the current allowable concentration based on the fissile material concentration limit referenced in the Yucca Mountain Project License Application (897 g/m 3 3 of glass or about 600 g Pu/canister). Based on historical process throughput data, this level was considered to represent a reasonable upper bound for Pu loading based on the ability to provide Pu containing feed to the DWPF. The task elements included evaluating the distribution of Pu in the glass (e.g. homogeneity), evaluating crystallization within the glass, evaluating select glass properties (with surrogates), and evaluating durability using the Product Consistency Test -- Method A (PCT-A). The behavior of Pu in the melter was evaluated using paper studies and corresponding analyses of DWPF melter pour samples.The results of the testing indicated that at 1 wt % Pu in the glass, the Pu was homogeneously distributed and did not result in any formation of plutonium-containing crystalline phases as long as the glass was prepared under 'well-mixed' conditions. The incorporation of 1 wt

  15. Immobilization of Uranium Silicide in Sintered Iron-Phosphate Glass

    International Nuclear Information System (INIS)

    Mateos, Patricia; Russo, Diego; Rodriguez, Diego; Heredia, A; Sanfilippo, M.; Sterba, Mario

    2003-01-01

    This work is a continuation of a previous one performed in vitrification of uranium silicide in borosilicate and iron-silicate glasses, by sintering.We present the results obtained with an iron-phosphate glass developed at our laboratory and we compare this results with those obtained with the above mentioned glasses. The main objective was to develop a method as simple as possible, so as to get a monolithic glass block with the appropriate properties to be disposed in a deep geological repository.The thermal transformation of the uranium silicide was characterized by DTA/TG analysis and X-ray diffraction.We determined the evolution of the crystalline phases and the change in weight.Calcined uranium silicide was mixed with natural U 3 O 8 , the amount of U 3 O 8 was calculated to simulate an isotopic dilution of 4%.This material was mixed with powdered iron-phosphate glass (in wt.%: 64,9 P 2 O 5 ; 22,7 Fe 2 O 3 ; 8,1 Al 2 O 3 ; 4,3 Na 2 O) in different proportions (in wt%): 7%, 10% y 15%.The powders were pressed and sintered at temperatures between 585 y 670 °C. Samples of the sintered pellet were prepared for the lixiviation tests (MCC-1P: monolithic samples; deionised water; 90° C; 7, 14 and 28 days).The samples showed a quite good durability (0,6 g.m -2 .day -1 ), similar to borosilicate glasses.The microstructure of the glass samples showed that the uranium particles are much better integrated to the glass matrix in the iron-phosphate glasses than in the borosilicate or iron-silicate glasses.We can conclude that the sintered product obtained could be a good alternative for the immobilization of nuclear wastes with high content of uranium, as the ones arising from the conditioning of research reactors spent fuels

  16. Water-Soluble Vitamin E-Tocopheryl Phosphate.

    Science.gov (United States)

    Zingg, Jean-Marc

    The hydrophobicity of vitamin E poses transport and metabolic challenges to regulate its bioavailability and to prevent its accumulation in lipid-rich tissues such as adipose tissue, brain, and liver. Water-soluble precursors of vitamin E (α-tocopherol, αT), such as its esters with acetate (αTA), succinate (αTS), or phosphate (αTP), have increased solubility in water and stability against reaction with free radicals, but they are rapidly converted during their uptake into the lipid-soluble vitamin E. Therefore, the bioavailability of these precursors as intact molecules is low; nevertheless, at least for αTS and αTP, the recent research has revealed unique regulatory effects on signal transduction and gene expression and the modulation of cellular events ranging from proliferation, survival/apoptosis, lipid uptake and metabolism, phagocytosis, long term potentiation, cell migration, telomere maintenance, and angiogenesis. Moreover, water-soluble derivatives of vitamin E including some based on αTP are increasingly used as components of nanocarriers for enhanced and targeted delivery of drugs and other molecules (vitamins, including αT and αTP itself, vitamin D3, carnosine, caffeine, docosahexaenoic acid (DHA), insulin) and cofactors such as coenzyme Q10. In this review, the chemical characteristics, transport, metabolic pathways, and molecular mechanisms of action of αTP in cells and tissues are summarized and put into perspective with its possible role in the prevention of a number of diseases. © 2018 Elsevier Inc. All rights reserved.

  17. Spectroscopic properties of highly Nd-doped lead phosphate glass

    Energy Technology Data Exchange (ETDEWEB)

    Novais, A.L.F. [Instituto de Física, Universidade Federal de Alagoas, Grupo de Fotônica e Fluidos Complexos, 57072-970 Maceió, AL (Brazil); Dantas, N.O. [Laboratório de Novos Materiais Isolantes e Semicondutores (LNMIS), Instituto de Física, Universidade Federal de Uberlândia, 38400-902 Uberlândia, MG (Brazil); Guedes, I. [Departamento de Física, Universidade Federal do Ceará, Campus do PICI, Caixa Postal 6030, 60455-760 Fortaleza, CE (Brazil); Vermelho, M.V.D., E-mail: vermelho@fis.ufal.br [Instituto de Física, Universidade Federal de Alagoas, Grupo de Fotônica e Fluidos Complexos, 57072-970 Maceió, AL (Brazil)

    2015-11-05

    The spectroscopic characteristics of highly Nd{sup 3+}-doped lead phosphate glasses (xNd:Pb{sub 3}(PO{sub 4}){sub 2}) have been investigated. The X-ray spectra show that the matrices are glassy up to 25 wt% of Nd{sup 3+} doping. From the Judd–Ofelt analysis we observe that while the Ω{sub (2)} parameter remains constant indicating that the 4f{sup N} and 4f{sup N−1}5 d{sup 1} configurations are not affected by the Nd{sup 3+} doping, the behavior of both Ω{sub (4)} and Ω{sub (6)} changes for 15 wt% of Nd{sup 3+} doping. The reduction of the Ω{sub (6)} parameter is related to the increase of the covalence bonding between the ligands and the Nd{sup 3+} ions. At this particular concentration, the radiative lifetime has a four-fold enhancement. Such behaviors are likely to be related to a modification in the glass structure for high Nd{sup 3+} concentrations. - Graphical abstract: Highly doped lead-phosphate glass matrix, with nominal concentration of up to 25 wt%, maintain the spectroscopic properties without deterioration. The analysis concerning the point of view of Nd{sup 3+} ions showed that high concentrations only affects the rare earth electronic charge density distribution. - Highlights: • Spectroscopic characterization of Nd{sub 2}O{sub 3} highly doped lead phosphate glasses. • Phosphate glass doped with Nd{sup 3+} for applications in photonic devices. • Judd–Ofelt analysis in phosphate glasses doped with Neodymium.

  18. Recent advances in phosphate laser glasses for high power applications

    International Nuclear Information System (INIS)

    Campbell, J.H.

    1996-01-01

    Recent advances in Nd-doped phosphate laser glasses for high-peak-power and high-average-power applications are reviewed. Compositional studies have progressed to the point that glasses can be tailored to have specific properties for specific applications. Non-radiative relaxation effects can be accurately modeled and empirical expressions have been developed to evaluate both intrinsic (structural) and extrinsic (contamination induced) relaxation effects. Losses due to surface scattering and bulk glass absorption have been carefully measured and can be accurately predicted. Improvements in processing have lead to high damage threshold (e.g. Pt inclusion free) and high thermal shock resistant glasses with improved edge claddings. High optical quality pieces up to 79 x 45 x 4cm 3 have been made and methods for continuous melting laser glass are under development

  19. Evaluation of phosphatic fertilizers of different solubility for common bean using isotopic methods

    International Nuclear Information System (INIS)

    Garcia Altunaga, Aurelio; Hernandez Barrueta, German; Nuviola Montoya, Antonio; Mendez Perez, Nancy; Herrero Echevarria, Grisel; Drevon, Jean Jacques

    2005-01-01

    Glass house experiments were carried out in the Experimental Station La Renee located in Habana province in the year 2003. The objective of this study was to evaluate the effectiveness of phosphorus (P) sources varying in solubility for common bean (Phaseolus vulgaris L.) nutrition using the isotopic dilution method with 32 P , growing under two soils: Acrisol and Rhodic Ferralsol. The P sources, evaluated in both soils were phosphate rock (PR) Trinidad de Guedes and PR partially solubilized at 50% with H 2 SO 4 , namely FPA 50, whereas single super phosphate (SS) and triple super phosphate (TSP) were used in the Acrisol and Rhodic Ferralsol Soils, respectively. The common bean genotypes were BAT 477, DOR 364, DOR 390 and Censa, and BAT 58, BAT 477, DOR 364 and CC-25-9(N) in the Acrisol and Rhodic Felrrasol soils, respectively. Dry matter production, P extraction, and the fraction and quantity of P in plants obtained from different P sources were evaluated, and P use efficiency of each P fertilizer were calculated. Single and tripe super phosphate and FPA 50 were effective P fertilizers in both soils whereas RF was not. (author) [es

  20. Structure and properties of gadolinium loaded calcium phosphate glasses

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Cuiling [Analytical and Testing Center, Southwest University of Science and Technology, Mianyang 621010 (China); State Key Laboratory Cultivation Base for Nonmetal Composites and Functional Materials, Southwest University of Science and Technology, Mianyang 621010 (China); Liang, Xiaofeng, E-mail: XFLiang@swust.edu.cn [Analytical and Testing Center, Southwest University of Science and Technology, Mianyang 621010 (China); State Key Laboratory Cultivation Base for Nonmetal Composites and Functional Materials, Southwest University of Science and Technology, Mianyang 621010 (China); Li, Haijian; Yu, Huijun; Li, Zhen [Analytical and Testing Center, Southwest University of Science and Technology, Mianyang 621010 (China); State Key Laboratory Cultivation Base for Nonmetal Composites and Functional Materials, Southwest University of Science and Technology, Mianyang 621010 (China); Yang, Shiyuan [State Key Laboratory Cultivation Base for Nonmetal Composites and Functional Materials, Southwest University of Science and Technology, Mianyang 621010 (China)

    2014-10-15

    The glass samples with composition xGd{sub 2}O{sub 3}–(50 − x)CaO–50P{sub 2}O{sub 5} (0 ⩽ x ⩽ 9 mol%) were prepared by the conventional melt quench method. The structure and properties of gadolinium loaded in calcium phosphate glasses were investigated using XRD, SEM, DTA, IR and Raman spectroscopy. The XRD and SEM analysis for the samples show that the majority of samples are amorphous, and crystallization occurs when the content of Gd{sub 2}O{sub 3} containing is up to 6 mol%. Two main crystalline phases, Ca{sub 2}P{sub 2}O{sub 7} and Gd{sub 3}(P{sub 2}O{sub 7}){sub 3}, are embedded in an amorphous matrix. IR and Raman data indicate that glass structure consists of predominantly metaphosphate (Q{sup 2}) units and the depolymerization of phosphate network with the addition of Gd{sub 2}O{sub 3}. Both the chemical durability and the glass transition temperature (T{sub g}) are improved with the increase of Gd{sub 2}O{sub 3}, which suggests that the Gd acts a role of strengthening the cross-links between the phosphate chains of the glass.

  1. Structure and properties of gadolinium loaded calcium phosphate glasses

    International Nuclear Information System (INIS)

    Wang, Cuiling; Liang, Xiaofeng; Li, Haijian; Yu, Huijun; Li, Zhen; Yang, Shiyuan

    2014-01-01

    The glass samples with composition xGd 2 O 3 –(50 − x)CaO–50P 2 O 5 (0 ⩽ x ⩽ 9 mol%) were prepared by the conventional melt quench method. The structure and properties of gadolinium loaded in calcium phosphate glasses were investigated using XRD, SEM, DTA, IR and Raman spectroscopy. The XRD and SEM analysis for the samples show that the majority of samples are amorphous, and crystallization occurs when the content of Gd 2 O 3 containing is up to 6 mol%. Two main crystalline phases, Ca 2 P 2 O 7 and Gd 3 (P 2 O 7 ) 3 , are embedded in an amorphous matrix. IR and Raman data indicate that glass structure consists of predominantly metaphosphate (Q 2 ) units and the depolymerization of phosphate network with the addition of Gd 2 O 3 . Both the chemical durability and the glass transition temperature (T g ) are improved with the increase of Gd 2 O 3 , which suggests that the Gd acts a role of strengthening the cross-links between the phosphate chains of the glass

  2. Iron Phosphate Glasses: An Alternative for Vitrifying Certain Nuclear Wastes

    International Nuclear Information System (INIS)

    Day, Delbert E.; Ray, Chandra S.; Cheol-Woon Kim

    2004-01-01

    Vitrification of nuclear waste in a glass is currently the preferred process for waste disposal. DOE currently approves only borosilicate (BS) type glasses for such purposes. However, many nuclear wastes, presently awaiting disposal, have complex and diverse chemical compositions, and often contain components that are poorly soluble or chemically incompatible in BS glasses. Such problematic wastes can be pre-processed and/or diluted to compensate for their incompatibility with a BS glass matrix, but both of these solutions increases the wasteform volume and the overall cost for vitrification. Direct vitrification using alternative glasses that utilize the major components already present in the waste is preferable, since it avoids pre-treating or diluting the waste, and, thus, minimizes the wasteform volume and overall cost

  3. Iron Phosphate Glasses: An Alternative for Vitrifying Certain Nuclear Wastes

    Energy Technology Data Exchange (ETDEWEB)

    Delbert E. Day; Chandra S. Ray; Cheol-Woon Kim

    2004-12-28

    Vitrification of nuclear waste in a glass is currently the preferred process for waste disposal. DOE currently approves only borosilicate (BS) type glasses for such purposes. However, many nuclear wastes, presently awaiting disposal, have complex and diverse chemical compositions, and often contain components that are poorly soluble or chemically incompatible in BS glasses. Such problematic wastes can be pre-processed and/or diluted to compensate for their incompatibility with a BS glass matrix, but both of these solutions increases the wasteform volume and the overall cost for vitrification. Direct vitrification using alternative glasses that utilize the major components already present in the waste is preferable, since it avoids pre-treating or diluting the waste, and, thus, minimizes the wasteform volume and overall cost.

  4. Structural and thermochemical properties of sodium magnesium phosphate glasses

    Energy Technology Data Exchange (ETDEWEB)

    Oueslati Omrani, Refka [Université de Tunis El Manar, Faculté des Sciences de Tunis, Chemistry Department, LR01SE10 Applied Thermodynamics Laboratory, 2092 Tunis (Tunisia); Kaoutar, Abdeltif; El Jazouli, Abdelaziz [LCMS, URAC 17, Faculté des Sciences Ben M’Sik, UH2MC, Casablanca (Morocco); Krimi, Saida [LPCMI, Faculté des Sciences Aïn Chok, UH2C, Casablanca (Morocco); Khattech, Ismail, E-mail: ismail.khattech@fst.rnu.tn [Université de Tunis El Manar, Faculté des Sciences de Tunis, Chemistry Department, LR01SE10 Applied Thermodynamics Laboratory, 2092 Tunis (Tunisia); Jemal, Mohamed [Université de Tunis El Manar, Faculté des Sciences de Tunis, Chemistry Department, LR01SE10 Applied Thermodynamics Laboratory, 2092 Tunis (Tunisia); Videau, Jean-Jacques [ICMCB, Institut de Chimie de la matière condensée, Université de Bordeaux 1 (France); Couzi, Michel [Institut des Sciences Moléculaires, CNRS-Université de Bordeaux 1 (France)

    2015-05-25

    Highlights: • Phosphate glasses were prepared by met quenching technique. • Structural study is investigated using FTIR, Raman and {sup 31}PNMR spectroscopy. • A 4.5% weight of H{sub 3}PO{sub 4} solution has use for glass dissolution. • Dissolution is endothermic for lower MgO content and becomes exothermic when x rises. - Abstract: Ternary phosphate based glasses with the general formula (50−x/2)Na{sub 2}O–xMgO–(50−x/2)P{sub 2}O{sub 5} (0 ⩽ x ⩽ 42.8 mol%), where the O/P ratio was varied from 3 to 3.75, have been prepared using a conventional melt quenching technique. Samples were investigated by means of density measurements, Fourier-transformed infrared (FTIR), Raman and {sup 31}P solid state magic angle spinning nuclear magnetic resonance (MAS-NMR) spectroscopies, differential scanning calorimetry (DSC), inductively coupled plasma atomic emission spectroscopy (ICP/AES) analysis and calorimetric dissolution. The depolymerization of metaphosphate chains are described by the decrease of Q{sup 2} tetrahedral sites allowing the formation of pyrophosphate groups (Q{sup 1}) revealed by spectroscopic investigations. As a result, the increase of density and glass transition temperature when x rises. Calorimetric study shows that the dissolution phenomenon is endothermic for a lower MgO content and becomes exothermic when magnesium oxide is gradually incorporated, suggesting the disruption of phosphate chains with increasing O/P ratio.

  5. Spectroscopic identification of rare earth elements in phosphate glass

    Science.gov (United States)

    Devangad, Praveen; Tamboli, Maktum; Muhammed Shameem, K. M.; Nayak, Rajesh; Patil, Ajeetkumar; Unnikrishnan, V. K.; Santhosh, C.; Kumar, G. A.

    2018-01-01

    In this work, rare earth-doped phosphate glasses were synthesized and characterized using three different spectroscopic techniques. The absorption spectra of the prepared praseodymium (Pr) and samarium (Sm) doped glasses, recorded by a UV-VIS-NIR spectrophotometer, show the characteristic absorption bands of these elements. To confirm this inference, laser-induced fluorescence spectra of Pr and Sm were obtained at a laser excitation of 442 nm. Their emission bands are reported here. The elemental analysis of these samples was carried out using a laser-induced breakdown spectroscopy (LIBS) system. Characteristic emission lines of Pr and Sm have been identified and reported by the recorded LIBS spectra of glass samples. Results prove that using these three complimentary spectroscopic techniques (absorption, fluorescence and LIBS), we can meaningfully characterize rare earth-doped glass samples.

  6. Hafnium in peralkaline and peraluminous boro-aluminosilicate glass, and glass subcomponents: a solubility study

    International Nuclear Information System (INIS)

    Davis, Linda L.; Darab, John G.; Qian, Maoxu; Zhao, Donggao; Palenik, Christopher S.; Li, Hong; Strachan, Denis M.; Li, Liyu

    2003-01-01

    A relationship between the solubility of hafnia (HfO2) and the host glass composition was explored by determining the solubility limits of HfO2 in peralkaline and peraluminous borosilicate glasses in the system SiO2-Al2O3-B2O3-Na2O, and in glasses in the system SiO2-Na2O-Al2O3 in air at 1450 C. The only Hf-bearing phase to crystallize in the peralkaline borosilicate melts is hafnia, while in the boron-free melts sodium-hafnium silicates crystallize. All peraluminous borosilicate melts crystallize hafnia, but the slightly peraluminous glasses also have sector-zoned hafnia crystals that contain Al and Si. The more peraluminous borosilicate glasses also crystallize a B-containing mullite. The general morphology of the hafnia crystals changes as peralkalinity (Na2O/(Na2O+Al2O3)) decreases, as expected in melts with increasing viscosity. In all of the glasses with Na2O > Al2O3, the solubility of hafnia is linearly and positively correlated with Na2O/(Na2O + Al2O3) or Na2O - Al2O3 (excess sodium), despite the presence of 5 to 16 mol% B2O3. The solubility of hafnia is higher in the sodium-aluminum borosilicate glasses than in the sodium-aluminosilicate glasses, suggesting that the boron is enhancing the effect that excess sodium has on the incorporation of Hf into the glass structure. The results of this solubility study are compared to other studies of high-valence cation solubility in B-free silicate melts. From this, for peralkaline B-bearing glasses, it is shown that, although the solubility limits are higher, the solution behavior of hafnia is the same as in B-free silicate melts previously studied. By comparison, also, it is shown that in peraluminous melts, there must be a different solution mechanism for hafnia: different than for peralkaline sodium-aluminum borosilicate glasses and different than for B-free silicate melts studied by others

  7. Preparation and characterization of phosphate glasses containing titanium and vanadium

    Energy Technology Data Exchange (ETDEWEB)

    Kaoua, S. [Laboratoire de Chimie du Solide, Faculte des Sciences Ain Chock, Casablanca (Morocco); Krimi, S. [Laboratoire de Chimie du Solide, Faculte des Sciences Ain Chock, Casablanca (Morocco)]. E-mail: krimisaida@yahoo.fr; El Jazouli, A. [Laboratoire de Chimie des Materiaux Solides, Faculte des Sciences Ben M' Sik, Casablanca (Morocco); Hlil, E.K. [Laboratoire de Cristallographie du CNRS, Grenoble (France)]. E-mail: hlil@grenoble.cnrs.fr; Waal, D. de [Department of Chemistry, University of Pretoria, 0002 Pretoria (South Africa)

    2007-02-21

    Na{sub 5-x}Ti{sub 1-x}V {sub x}(PO{sub 4}){sub 3} (0 {<=} x {<=} 1) phosphates glasses have been obtained in air by direct fusion of Na{sub 2}CO{sub 3}, TiO{sub 2}, V{sub 2}O{sub 5} and (NH{sub 4}){sub 2}HPO{sub 4}. Vitreous Na{sub 5}Ti(PO{sub 4}){sub 3} is colourless while the glasses containing vanadium are green, due to the reduction of V{sup 5+} to V{sup 4+}. Glass transition and crystallization temperatures (T {sub g}, T {sub c}) decrease when the amount of vanadium increases. EPR, Raman and UV-vis spectra have been investigated. The results are consistent with the presence of V{sup 4+} ions in distorted octahedra with very strong V-O bond.

  8. Iron phosphate glass: a promising matrix for the immobilization of Cs and Mo

    International Nuclear Information System (INIS)

    Hemadevi, V.; Joseph, Kitheri

    2015-01-01

    Presently, borosilicate glass (BSG) is the acceptable vitrification matrix for the immobilization of high level waste. The solubility of Mo in BSG is limited in the presence of Cs. As per the literature, solubility of Mo in BSG is about 2.5 wt. % in the presence of Cs. Hence it is difficult to immobilize nuclear waste rich in Cs and Mo in borosilicate glass. It is observed that the composition of Cs and Mo expressed as oxides are 10.4 and 14.7 wt. % respectively in simulated fast reactor waste. Iron phosphate glass containing 20 wt. % simulated fast reactor waste (referred as IP20FRW) was synthesized and characterized. IP20FRW contains ~ 3 wt. % of molybdenum oxide along with 2 wt. % cesium oxide. IPG is a suitable matrix for the immobilization of Cs and Mo separately. Hence it is essential to understand the glass characteristics of IPG containing both Cs and Mo. This paper explores systematic loading of both Cs and Mo such that the final composition corresponds to 10.5 wt. % Cs 2 O-15 wt. % MoO 3 -31.9 wt. % Fe 2 O 3 -42.6 wt. % P 2 O 5 . In addition to synthesis, the present study also includes understanding the change in glass characteristics of IPG containing both Cs and Mo. The possibility of higher percent loading of both Cs and Mo in IPG demonstrates the better glass forming characteristics of IPG. The synthesis and characterization of Cs-Mo loaded glasses will be discussed in this paper. (author)

  9. 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.

  10. Lead iron phosphate glass as a containment medium for disposal of high-level nuclear waste

    International Nuclear Information System (INIS)

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

    1989-01-01

    This patent describes 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 0 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. The lead-iron phosphate waste glasses can be prepared with minimal modification of the technology developed for processing borosilicate glass nuclear wasteforms

  11. Immobilization of {sup 99}Tc (Re) using Iron-Phosphate Glasses

    Energy Technology Data Exchange (ETDEWEB)

    Heo, Jong; Xu, Kai; Um, Woo Yong; Hrma, Pavel [Pohang Univ. of Science and Technology, Pohang (Korea, Republic of)

    2012-05-15

    Technetium-99 ({sup 99}Tc) is a fission product artificially generated during the irradiation of {sup 235}U for commercial power production or {sup 239}Pu for nuclear weapons. Under oxidizing conditions, the dominant species of Tc, the pertechnetate anion (TcO{sub 4} {sup -}), is highly soluble in ground water and thus easily transports through the geologic systems. In addition, because of its high fission yield ({approx}6 %) and long half-life (2.1x10{sup 5} yr), immobilization of {sup 99}Tc has been investigated for decades. Several waste forms such as metallic alloys, sintered titanate ceramics and chemically bonded phosphate ceramics have been proposed to encapsulate {sup 99}Tc. They have not yet been realized in the industrial-scale, mostly either due to the high volatilization of {sup 99}Tc during high temperature process (>1300 .deg. C), or the low {sup 99}Tc loading. Iron-phosphate (FeP) glasses have been developed as alternative waste forms because of their chemical durability equivalent to borosilicate glasses. Additionally, vitrification of radioactive waste by FeP glasses can be done at a relatively low temperature ({approx}1000 .deg. C) and the low-temperature process can reduce the volatilization of {sup 99}Tc significantly. Thus, this work reports the immobilization of {sup 99}Tc by FeP glasses using rhenium (Re) as a surrogate. We also examine the chemical durability of Re-containing FeP glasses using product consistency test (PCT). Experimental results reveal that FeP glass can become a promising candidate for immobilizing {sup 99}Tc

  12. Comprehensive thermal and structural characterization of antimony-phosphate glass

    Science.gov (United States)

    Moustafa, S. Y.; Sahar, M. R.; Ghoshal, S. K.

    For the first time, we prepare new ternary glass systems of composition (95-x)Sb2O3-xP2O5-5MgO, where x = 45, 40, 35 mol%; (85-x)Sb2O3-xP2O5-15MgO, where x = 55, 35, 25 mol%; (75-x)Sb2O3-xP2O5-25MgO, where x = 45, 35, 25 mol%; and 60Sb2O3-(40-x)P2O5-xMgO, where x = 10, 20 mol% via melt-quenching method. Synthesized glasses are characterized using XRD, FESEM, EDX, and TG/DTA measurements. The influence of varying modifier concentrations on their thermal properties is evaluated. The XRD patterns confirmed the amorphous nature of samples. SEM images demonstrated interesting phase formation with ribbons-like texture. Five crystalline phases are evidenced in the ternary diagram which are antimony phosphate and antimony orthophosphate as major phases as well as magnesium phosphate, magnesium cyclo-tetraphosphate and cervantite as minor phases. EDX spectra detected the right elemental traces. Detailed thermal analysis of these glasses revealed their high-molecular polymer character for Sb2O3 content greater than 50 mol%. Three different glass transition temperatures are achieved around 276, 380-381 and 422-470 °C depending on the composition. Furthermore, the solidus and liquidus temperature are found to decrease with increasing Sb2O3 and increases for MgO contents till 15 mol% and then decrease, where the lowest recorded solidus temperature is 426 °C. This observation may open up new research avenues for antimony based ternary glasses and an exploitation of the derived results for optoelectronics applications, photonic devices and non-linear optical devices.

  13. Ytterbium-Phosphate Glass for Microstructured Fiber Laser

    Directory of Open Access Journals (Sweden)

    Ryszard Stępień

    2014-06-01

    Full Text Available In the paper, we report on the development of a synthesis and melting method of phosphate glasses designed for active microstructured fiber manufacturing. Non-doped glass synthesized in a P2O5-Al2O3-BaO-ZnO-MgO-Na2O oxide system served as the matrix material; meanwhile, the glass was doped with 6 mol% (18 wt% of Yb2O3, as fiber core. The glasses were well-fitted in relation to optical (refractive index and thermal proprieties (thermal expansion coefficient, rheology. The fiber with the Yb3+-doped core, with a wide internal photonic microstructure for a laser pump, as well as with a high relative hole size in the photonic outer air-cladding, was produced. The laser built on the basis of this fiber enabled achieving 8.07 W of output power with 20.5% slope efficiency against the launched pump power, in single-mode operation M2 = 1.59, from a 53 cm-long cavity.

  14. Synthesis and characterization of niobium and iron phosphate glasses for U3O8 immobilization

    International Nuclear Information System (INIS)

    Ghussn, Luciana

    2005-01-01

    Niobium and iron phosphate glasses were produced by melting inorganic compound mixtures in electric furnaces and microwave ovens. The chemical durability was compared among niobium phosphate glasses produced by both processes, and equivalent results were obtained. Leaching tests were also performed to compare the chemical durability among monolithic glass blocks and sintered glasses. The glass transition, crystallization and melting temperatures as well the Hruby parameter (K H ) and the activation energy for crystallization were determined from differential thermal analysis of niobium phosphate glasses produced in electric furnaces. Niobium phosphate glasses are thermally more stable (K H =0.82 +- 0.04) than iron phosphate glasses (K H = 0.42 +- 0.03). Sintered glasses were produced from particles with different particle size distributions and sintering temperatures in the range of 720 - 800 deg C for niobium phosphate and 530 - 680 deg C for iron phosphate glasses. The sintering process was suitable because a glass with composition 37P 2 O 5 -23K 2 O-40Nb 2 O 5 showing leaching rate of 10 -6 g.cm -2 .d -1 , 99 % of the monolithic density and none crystalline phases was obtained. This glass only crystallizes itself after re heating at temperatures above 800 deg C , showing two crystalline phases identified as KNb 3 O 8 e K 3 NbP 2 O 9 . The activation energies for crystallization are 496 +- 7 kJ/mol and 513 +- 14 kJ/mol. Niobium phosphate sintered glasses are better densified than sintered iron phosphate glasses. The leaching rate of sintered glasses that show open porosity is higher than monolithic glass blocks. This effect is related to an increase of the surface area associated to open porous and, a correction of the value of the surface area used to calculate the leaching rate is required. A model was proposed based on the surface area of spherical porous to take in account that effect. Even after correcting the surface area, the leaching rates of sintered

  15. Alkaline resistant phosphate glasses and method of preparation and use thereof

    Science.gov (United States)

    Brow, Richard K.; Reis, Signo T.; Velez, Mariano; Day, Delbert E.

    2010-01-26

    A substantially alkaline resistant calcium-iron-phosphate (CFP) glass and methods of making and using thereof. In one application, the CFP glass is drawn into a fiber and dispersed in cement to produce glass fiber reinforced concrete (GFRC) articles having the high compressive strength of concrete with the high impact, flexural and tensile strength associated with glass fibers.

  16. In vitro bioactivity of soda lime borate glasses with substituted SrO in sodium phosphate solution

    Directory of Open Access Journals (Sweden)

    Mohamed A. Marzouk

    2014-09-01

    Full Text Available Borate glasses with the basic composition 0.6B2O3·0.2Na2O·0.2CaO and SrO progressively substituting CaO were prepared and characterized for their bone-bonding ability. The obtained glasses were thermally treated and converted to their glass-ceramic derivatives. In this study, FTIR spectral analyses were done for the prepared glasses and glass-ceramics before and after immersion in a sodium phosphate solution for extended times. The appearance of two IR bands within the spectral range 550–680 cm-1 after immersion confirms the formation of hydroxyapatite. X-ray diffraction studies and scanning electron microscope analysis supported the obtained infrared spectroscopy results. The solubility test (measurements of the weight loss in aqueous sodium phosphate solution was conducted for measuring the dissolution of both glassy and crystalline derivatives to find out the role of SrO. The corrosion behaviour of the glasses and glass-ceramics indicate the increase of weight loss with the increase of SrO content. Different suggested proposals were introduced to explain this abnormal behaviour.

  17. Phosphate-based glasses: Prediction of acoustical properties

    Science.gov (United States)

    El-Moneim, Amin Abd

    2016-04-01

    In this work, a comprehensive study has been carried out to predict the composition dependence of bulk modulus and ultrasonic attenuation coefficient in the phosphate-based glass systems PbO-P2O5, Li2O-TeO2-B2O3-P2O5, TiO2-Na2O-CaO-P2O5 and Cr2O3-doped Na2O-ZnO-P2O5 at room temperature. The prediction is based on (i) Makishima-Mackenzie theory, which correlates the bulk modulus with packing density and dissociation energy per unit volume, and (ii) Our recently presented semi-empirical formulas, which correlate the ultrasonic attenuation coefficient with the oxygen density, mean atomic ring size, first-order stretching force constant and experimental bulk modulus. Results revealed that our recently presented semi-empirical formulas can be applied successfully to predict changes of ultrasonic attenuation coefficient in binary PbO-P2O5 glasses at 10 MHz frequency and in quaternary Li2O-TeO2-B2O3-P2O5, TiO2-Na2O-CaO-P2O5 and Cr2O3-Na2O-ZnO-P2O5 glasses at 5 MHz frequency. Also, Makishima-Mackenzie theory appears to be valid for the studied glasses if the effect of the basic structural units that present in the glass network is taken into account.

  18. The antimicrobial activity of as-prepared silver-loaded phosphate glasses and zirconium phosphate

    International Nuclear Information System (INIS)

    Jing, Wang; Jiang, Ji Zhi; Yang, Yang; Yan, Zhao Chun; Yan, Wang Xiao; He, Shui Zhong

    2016-01-01

    The antimicrobial activities of silver-loaded zirconium phosphate (JDG) and silver-loaded phosphate glasses (ZZB) against Escherichia coli were studied. Although the silver content in JDG was higher than that in ZZB, ZZB suspensions showed better antimicrobial property than JDG suspensions, especially at low concentrations. The antimicrobial activity was analyzed using minimum inhibitory concentrations, bacterial inhibition ring tests, and detection of silver ions in the suspensions. Furthermore, the amounts of silver ions in suspensions with/without bacterial cells were analyzed. Results revealed that only a portion of released silver ions could be adsorbed by E. coli cells, which are critical to cell death. The damaged microstructures of E. coli cells observed by transmission electron microscopy may further prove that the adsorbed silver ions play an important role in the antimicrobial process.

  19. Structure of cesium loaded iron phosphate glasses: An infrared and Raman spectroscopy study

    International Nuclear Information System (INIS)

    Joseph, Kitheri; Premila, M.; Amarendra, G.; Govindan Kutty, K.V.; Sundar, C.S.; Vasudeva Rao, P.R.

    2012-01-01

    The structure of cesium loaded iron phosphate glasses (IPG) was investigated using infrared and Raman spectroscopy. The spectra of the cesium doped samples revealed a structural modification of the parent glass owing to the incorporation of cesium. The structural changes could be correlated with the variation observed in the glass transition temperature of these glasses. Increased Cs-mediated cationic cross linking appears to be the reason for the initial rise in glass transition temperature up to 21 mol% Cs 2 O in IPG; while, breakdown of the phosphate network with increasing cesium content, brings down the glass transition temperature.

  20. 3 and 4 oxidation state element solubilities in borosilicate glasses. Implement to actinides in nuclear glasses

    International Nuclear Information System (INIS)

    Cachia, J.N.

    2005-12-01

    In order to ensure optimal radionuclides containment, the knowledge of the actinide loading limits in nuclear waste glasses and also the comprehension of the solubilization mechanisms of these elements are essential. A first part of this manuscript deals with the study of the differences in solubility of the tri and tetravalent elements (actinides and surrogates) particularly in function of the melting temperature. The results obtained indicate that trivalent elements (La, Gd, Nd, Am, Cm) exhibit a higher solubility than tetravalent elements (Hf, Th, Pu). Consequently, it was planned to reduce plutonium at the oxidation state (III), the later being essentially tetravalent in borosilicate glasses. An innovating reduction process of multi-valent elements (cerium, plutonium) using silicon nitride has been developed in a second part of this work. Reduced plutonium-bearing glasses synthesized by Si 3 N 4 addition made it possible to double the plutonium solubility from 2 to 4 wt% at 1200 deg C. A structural approach to investigate the differences between tri and tetravalent elements was finally undertaken. These investigations were carried out by X-rays Absorption Spectroscopy (EXAFS) and NMR. Trivalent rare earth and actinide elements seem to behave as network modifiers while tetravalent elements rather present true intermediaries' behaviour. (author)

  1. Role of lead as modifier on the properties of lead iron phosphate nuclear waste glasses

    International Nuclear Information System (INIS)

    Hazra, G.; Mitra, P.; Das, T.

    2011-01-01

    Lead-iron phosphate glasses are a promising new waste form for the safe immobilization of both high level defence and high level commercial radioactive waste for long term disposal. Lead iron phosphate glasses have several advantages such as lower aqueous corrosion rate, lower processing temperature etc. (author)

  2. Effect of Phosphate, Fluoride, and Nitrate on Gibbsite Dissolution Rate and Solubility

    International Nuclear Information System (INIS)

    Herting, Daniel L.

    2014-01-01

    Laboratory tests have been completed with simulated tank waste samples to investigate the effects of phosphate, fluoride, and nitrate on the dissolution rate and equilibrium solubility of gibbsite in sodium hydroxide solution at 22 and 40 deg C. Results are compared to relevant literature data and to computer model predictions. The presence of sodium nitrate (3 M) caused a reduction in the rate of gibbsite dissolution in NaOH, but a modest increase in the equilibrium solubility of aluminum. The increase in solubility was not as large, though, as the increase predicted by the computer model. The presence of phosphate, either as sodium phosphate or sodium fluoride phosphate, had a negligible effect on the rate of gibbsite dissolution, but caused a slight increase in aluminum solubility. The magnitude of the increased solubility, relative to the increase caused by sodium nitrate, suggests that the increase is due to ionic strength (or water activity) effects, rather than being associated with the specific ion involved. The computer model predicted that phosphate would cause a slight decrease in aluminum solubility, suggesting some Al-PO4 interaction. No evidence was found of such an interaction

  3. Radiation Shielding Properties Comparison of Pb-Based Silicate, Borate, and Phosphate Glass Matrices

    Directory of Open Access Journals (Sweden)

    Suwimon Ruengsri

    2014-01-01

    Full Text Available Theoretical calculations of mass attenuation coefficients, partial interactions, atomic cross-section, and effective atomic numbers of PbO-based silicate, borate, and phosphate glass systems have been investigated at 662 keV. PbO-based silicate glass has been found with the highest total mass attenuation coefficient and then phosphate and borate glasses, respectively. Compton scattering has been the dominate interaction contributed to the different total attenuation coefficients in each of the glass matrices. The silicate and phosphate glass systems are more appropriate choices as lead-based radiation shielding glass than the borate glass system. Moreover, comparison of results has shown that the glasses possess better shielding properties than standard shielding concretes, suggesting a smaller size requirement in addition to transparency in the visible region.

  4. Structural features of silver-doped phosphate glasses in zone of femtosecond laser-induced modification

    Science.gov (United States)

    Vasileva, A. A.; Nazarov, I. A.; Olshin, P. K.; Povolotskiy, A. V.; Sokolov, I. A.; Manshina, A. A.

    2015-10-01

    Femtosecond (fs) laser writing of two-dimensional microstructures (waveguides) is demonstrated in bulk phosphate glasses doped with silver ions. Silver-content phosphate and silver-content niobium-phosphate glasses with high concentration of silver oxide 55 mol% were used as samples for fs laser writing. The chemical network structure of the synthesized samples is analyzed through Raman spectroscopy and was found to be strongly sensitive to Nb incorporation. It was found that the direct laser writing process enables not only reorganization of glass network, but also formation of color centers and silver nanoparticles that are revealed in appearance of luminescence signal and plasmon absorption. The process of NPs' formation is more efficient for Nb-phosphate glass, while color centers are preferably formed in phosphate glass.

  5. Properties and structure of high erbium doped phosphate glass for short optical fibers amplifiers

    International Nuclear Information System (INIS)

    Seneschal, Karine; Smektala, Frederic; Bureau, Bruno; Floch, Marie Le; Jiang Shibin; Luo, Tao; Lucas, Jacques; Peyghambarian, Nasser

    2005-01-01

    New phosphate glasses have been developed in order to incorporate high rare-earth ions concentrations. These glasses present a great chemical stability and a high optical quality. The phosphate glass network is open, very flexible, with a linkage of the tetrahedrons very disordered and contains a larger number of non-bridging oxygens (66%). The great stability and resistance against crystallization associated with the possibility to incorporate high doping concentration of rare-earth ions in these phosphate glasses make them very good candidates for the realization of ultra short single mode amplifiers with a high gain at 1.55 μm

  6. Lead iron phosphate glass as a containment medium for disposal of high-level nuclear waste

    Science.gov (United States)

    Boatner, Lynn A.; Sales, Brian C.

    1989-01-01

    Lead-iron phosphate glasses containing a high level of Fe.sub.2 O.sub.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.degree. 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.sup.2 to 10.sup.3 times lower than the corrosion rate of a comparable borosilicate nuclear waste glass. The presence of Fe.sub.2 O.sub.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.degree. C., since they exhibit very low melt viscosities in the 800.degree. to 1050.degree. C. temperature range. These waste-loaded glasses do not readily devitrify at temperatures as high as 550.degree. C. and are not adversely affected by large doses of gamma radiation in H.sub.2 O at 135.degree. C. The lead-iron phosphate waste glasses can be prepared with minimal modification of the technology developed for processing borosilicate glass nuclear wasteforms.

  7. Structural and electrical properties of iron molybdenum phosphate glasses

    International Nuclear Information System (INIS)

    De Oliveira, R.S.; Quixada-Ceara, Univ. Estadual do Ceara; De Paiva, J.A.C.; De Araujo, M.A.B.; Sombra, A. S.B.

    1998-01-01

    iron molybdenum phosphate glasses (xMoO 3 ·(0.6 - x)P 2 O 5 ·0.4Li 2 O) : yFe 2 O 2 with 0≤x≤ 0.6 and y = 0.03 (mol%) prepared in ambient atmosphere using the melt quenching technique were studied by using DC electrical conductivity, 57 Fe Moessbauer and infrared spectroscopies. The Dc conductivity depends on the MoO 3 concentration x. It was observed that, with increasing x, the ratio Fe 2+ /(Fe 3+ + Fe 2+ ) and the Dc conductivity increase. Infrared spectroscopy and X-ray powder diffraction indicate that a Li 2 MoO 4 crystalline phase is present for high MoO 3 content samples (x = 0.5, 0.6)

  8. Radiation Shielding Properties Comparison of Pb-Based Silicate, Borate, and Phosphate Glass Matrices

    OpenAIRE

    Ruengsri, Suwimon

    2014-01-01

    Theoretical calculations of mass attenuation coefficients, partial interactions, atomic cross-section, and effective atomic numbers of PbO-based silicate, borate, and phosphate glass systems have been investigated at 662 keV. PbO-based silicate glass has been found with the highest total mass attenuation coefficient and then phosphate and borate glasses, respectively. Compton scattering has been the dominate interaction contributed to the different total attenuation coefficients in each of th...

  9. High temperature oxidation and crystallization behavior of phosphate glass compositions

    International Nuclear Information System (INIS)

    Russo, Diego; Rodriguez, Diego; Grumbaum, N.; Gonzalez Oliver, Carlos

    2003-01-01

    We analyzed the thermal transformation of three iron phosphate glasses having the following nominal compositions: M4 [70% P 2 O 5 , 30% Fe 2 O 3 ], M5 [85% M4, 15% UO 2 ] y M7 [69.7% P 2 O 5 , 28.6% Fe 2 O 3 , 1,7% Al 2 O 3 ]. Thermogravimetric analysis, DTA (differential thermal analysis) and SAXS (Small Angle X-ray Scattering) were performed.It was observed that it is easily possible to produce glasses in these systems having very low crystallinity.We could determine the final stable crystalline phases [Fe 4 (P 2 O 7 ) 3 , Fe(PO 3 ) 3 and Fe 3 (P 2 O 7 ) 2 ].The presence of uranium ions affects not only the redox effects but also the crystallization of the system.SAXS data obtained during the heating in vacuum up to ∼600degC, gave some variation of scattering intensities vs. scattering vector suggesting the development of an extra phase or some kind inhomogeneities that seems to disappear on heating

  10. Evaluation of lead-iron-phosphate glass as a high-level waste form

    International Nuclear Information System (INIS)

    Chick, L.A.; Bunnell, L.R.; Strachan, D.M.; Kissinger, H.E.; Hodges, F.N.

    1986-01-01

    The lead-iron-phosphate nuclear waste glass developed at Oak Ridge National Laboratory (ORNL) was evaluated for its potential as an improvement over the current reference waste form, borosilicate glass. Vitreous lead-iron-phosphate glass appears to have substantially better chemical durability than borosilicate glass. However, severe crystallization leading to deteriorated chemical durability would result if this glass were poured into large canisters as is presently done with borosilicate glass. Cesium leach rates from this crystallized material are orders of magnitude greater than those from borosilicate glass. Therefore, in order to realize the performance advantages of the lead-iron-phosphate material in a nuclear waste form, it would be necessary to process it so that it is rapidly cooled, thus retaining its vitreous structure. 22 refs., 4 figs., 4 tabs

  11. A new paramagnetic center of copper ion γ-irradiated phosphate glasses

    International Nuclear Information System (INIS)

    Bogomolova, L.D.; Fedorov, A.G.; Jachkin, V.A.; Lazukin, V.N.; Pavlushkina, T.K.

    1981-01-01

    In the present paper are shown the results of EPR and optical absorption investigations of copper ions in γ-irradiated sodium-phosphate glasses and in MO-P 2 O 5 glasses (M = MG,Ca, Sr, Zn, Ba) containing copper and comparisons are made with the data for sodium-silicate glasses. (orig./HOF)

  12. Enhanced Luminescent Properties in Tm3+/Dy3+ Co-doped Transparent Phosphate Glass Ceramic

    OpenAIRE

    Yao L. Q.; Chen G. H.; Zhong H. J.; Cui S. C.; Li F.; Gan J.Y.

    2016-01-01

    Novel Tm3+/Dy3+ co-doped phosphate glass and glass ceramic samples for white light emitting diodes were prepared by melt quenching method. Under 353 nm excitation, the colors of the luminescence of the glass and glass ceramic samples are white. The CIE chromaticity coordinates (0.338, 0.328) of the emission from the glass ceramic is close to the standard white-light illumination (0.333, 0.333). Compared to the glass, the fluorescence intensity in the glass ceramic is greatly enhanced.

  13. Molecular Dynamics Simulation of the Structure and Properties of Lithium Phosphate Glasses

    Energy Technology Data Exchange (ETDEWEB)

    Liang, J-J; Cygan, R.T.; Alam, T.M.

    1999-07-09

    A new forcefield model was developed for the computer simulation of phosphate materials that have many important applications in the electronics and biomedical industries. The model provides a fundamental basis for the evaluation of phosphate glass structure and thermodynamics. Molecular dynamics simulations of a series of lithium phosphate glass compositions were performed using the forcefield model. A high concentration of three-membered rings (P{sub 3}O{sub 3}) occurs in the glass of intermediate composition (0.2 Li{sub 2}O {center_dot} 0.8P{sub 2}O{sub 5}) that corresponds to the minimum in the glass transition temperature curve for the compositional series. Molecular orbital calculations of various phosphate ring clusters indicate an increasing stabilization of the phosphate ring structure going from two- to four-membered rings.

  14. Effects of Nanodiamond Abrasive Friability in Experimental MR Fluids with Phosphate Laser Glass LHG-8 and Other Optical Glasses

    Energy Technology Data Exchange (ETDEWEB)

    DeGroote, J.E.; Marino, A.E.; Wilson, J.P.; Spencer, K.E.; Jacobs, S.D.

    2005-09-22

    Research is currently being conducted to better understand the role that nanodiamond abrasives play in the removal process of Magnetorheological Finishing (MRF). The following presents removal rate data for a set of six optical glasses that were spotted (not polished out) with four different MR fluids, as well as texturing/smoothing data for phosphate laser glass LHG-8.

  15. Studeis on the immobilization of water soluble phosphatic fertilizer in some soils with 32P

    International Nuclear Information System (INIS)

    Zhang Yumei; Li Rensheng; Xu Xinyu

    1985-01-01

    Using superphosphate lablled with 32 P, we studied immobilization of water-soluble phosphatic fertilizer on 12 typies of soil. The experimental result showed that major factors to govern immobilization of water-soluble phosphatic fertilizer are: quickly availible Fe that showed positive correlation with the immobilization when it was 4.64-65.72 ppm; and pH that showed negative correlation with the immobilization when it was between 5.35 and 8.88. CaCO 3 and organic matter showed a great effect on the immobilization though there wasn't obvious correlation among them

  16. Evaluation of ammonium nitrate phosphate (Suphala) having different water soluble phosphorus levels on black soils

    International Nuclear Information System (INIS)

    Deo Dutt; Mutatkar, V.K.; Chapke, V.G.

    1974-01-01

    Efficiency of the laboratory prepared 32 P tagged ammonium nitrate phosphate (Suphala) varying in water soluble P was studied both on calcareous and non-calcareous soils of Maharashtra for bajra and wheat crops under greenhouse conditions. The results revealed a significant increase in dry matter production and uptake of total and fertilizer P with Suphala containing 30-32% water-soluble phosphorus. (author)

  17. Laser properties of an improved average-power Nd-doped phosphate glass

    International Nuclear Information System (INIS)

    Payne, S.A.; Marshall, C.D.; Bayramian, A.J.

    1995-01-01

    The Nd-doped phosphate laser glass described herein can withstand 2.3 times greater thermal loading without fracture, compared to APG-1 (commercially-available average-power glass from Schott Glass Technologies). The enhanced thermal loading capability is established on the basis of the intrinsic thermomechanical properties (expansion, conduction, fracture toughness, and Young's modulus), and by direct thermally-induced fracture experiments using Ar-ion laser heating of the samples. This Nd-doped phosphate glass (referred to as APG-t) is found to be characterized by a 29% lower gain cross section and a 25% longer low-concentration emission lifetime

  18. Chemical analysis of simulated high level waste glasses to support stage III sulfate solubility modeling

    Energy Technology Data Exchange (ETDEWEB)

    Fox, K. M. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL)

    2016-03-17

    The U.S. Department of Energy (DOE), Office of Environmental Management (EM) is sponsoring an international, collaborative project to develop a fundamental model for sulfate solubility in nuclear waste glass. The solubility of sulfate has a significant impact on the achievable waste loading for nuclear waste forms within the DOE complex. These wastes can contain relatively high concentrations of sulfate, which has low solubility in borosilicate glass. This is a significant issue for low-activity waste (LAW) glass and is projected to have a major impact on the Hanford Tank Waste Treatment and Immobilization Plant (WTP). Sulfate solubility has also been a limiting factor for recent high level waste (HLW) sludge processed at the Savannah River Site (SRS) Defense Waste Processing Facility (DWPF). The low solubility of sulfate in glass, along with melter and off-gas corrosion constraints, dictate that the waste be blended with lower sulfate concentration waste sources or washed to remove sulfate prior to vitrification. The development of enhanced borosilicate glass compositions with improved sulfate solubility will allow for higher waste loadings and accelerate mission completion.The objective of the current scope being pursued by SHU is to mature the sulfate solubility model to the point where it can be used to guide glass composition development for DWPF and WTP, allowing for enhanced waste loadings and waste throughput at these facilities. A series of targeted glass compositions was selected to resolve data gaps in the model and is identified as Stage III. SHU fabricated these glasses and sent samples to SRNL for chemical composition analysis. SHU will use the resulting data to enhance the sulfate solubility model and resolve any deficiencies. In this report, SRNL provides chemical analyses for the Stage III, simulated HLW glasses fabricated by SHU in support of the sulfate solubility model development.

  19. Simulation of alpha decay of actinides in iron phosphate glasses by ion irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Dube, Charu L., E-mail: dubecharu@gmail.com; Stennett, Martin C.; Gandy, Amy S.; Hyatt, Neil C.

    2016-03-15

    Highlights: • Alpha decay of actinides in iron phosphate glasses is simulated by employing ion irradiation technique. • FTIR and Raman spectroscopic measurements confirm modification of glass network. • The depolymerisation of glass network after irradiation is attributed to synergetic effect of nuclear and electronic losses. - Abstract: A surrogate approach of ion beam irradiation is employed to simulate alpha decay of actinides in iron phosphate nuclear waste glasses. Bismuth and helium ions of different energies have been selected for simulating glass matrix modification owing to radiolysis and ballistic damage due to recoil atoms. Structural modification and change in coordination number of network former were probed by employing Reflectance Fourier-Transform Infrared (FT-IR), and Raman spectroscopies as a consequence of ion irradiation. Depolymerisation is observed in glass sample irradiated at intermediate energy of 2 MeV. Helium blisters of micron size are seen in glass sample irradiated at low helium ion energy of 30 keV.

  20. Study of structural, electrical, and dielectric properties of phosphate-borate glasses and glass-ceramics

    Energy Technology Data Exchange (ETDEWEB)

    Melo, B. M. G.; Graça, M. P. F., E-mail: mpfg@ua.pt; Prezas, P. R.; Valente, M. A. [Physics Department (I3N), Aveiro University, Campus Universitário de Santiago, Aveiro (Portugal); Almeida, A. F.; Freire, F. N. A. [Mechanics Engineering Department, Ceará Federal University, Fortaleza (Brazil); Bih, L. [Equipe Physico-Chimie la Matière Condensée, Faculté des Sciences de Meknès, Meknès (Morocco)

    2016-08-07

    In this work, phosphate-borate based glasses with molar composition 20.7P{sub 2}O{sub 5}–17.2Nb{sub 2}O{sub 5}–13.8WO{sub 3}–34.5A{sub 2}O–13.8B{sub 2}O{sub 3}, where A = Li, Na, and K, were prepared by the melt quenching technique. The as-prepared glasses were heat-treated in air at 800 °C for 4 h, which led to the formation of glass-ceramics. These high chemical and thermal stability glasses are good candidates for several applications such as fast ionic conductors, semiconductors, photonic materials, electrolytes, hermetic seals, rare-earth ion host solid lasers, and biomedical materials. The present work endorses the analysis of the electrical conductivity of the as-grown samples, and also the electrical, dielectric, and structural changes established by the heat-treatment process. The structure of the samples was analyzed using X-Ray powder Diffraction (XRD), Raman spectroscopy, and density measurements. Both XRD and Raman analysis confirmed crystals formation through the heat-treatment process. The electrical ac and dc conductivities, σ{sub ac} and σ{sub dc}, respectively, and impedance spectroscopy measurements as function of the temperature, varying from 200 to 380 K, were investigated for the as-grown and heat-treated samples. The impedance spectroscopy was measured in the frequency range of 100 Hz–1 MHz.

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

    Science.gov (United States)

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

    2014-04-01

    This paper investigates the effect of fiber drawing on the thermal and structural properties as well as on the glass reactivity of a phosphate glass in tris(hydroxymethyl)aminomethane-buffered (TRIS) solution and simulated body fluid (SBF). The changes induced in the thermal properties suggest that the fiber drawing process leads to a weakening and probable re-orientation of the POP bonds. Whereas the fiber drawing did not significantly impact the release of P and Ca, an increase in the release of Na into the solution was noticed. This was probably due to small structural reorientations occurring during the fiber drawing process and to a slight diffusion of Na to the fiber surface. Both the powders from the bulk and the glass fibers formed a Ca-P surface layer when immersed in SBF and TRIS. The layer thickness was higher in the calcium and phosphate supersaturated SBF than in TRIS. This paper for the first time presents the in vitro reactivity and optical response of a phosphate-based bioactive glass (PBG) fiber when immersed in SBF. The light intensity remained constant for the first 48h after which a decrease with three distinct slopes was observed: the first decrease between 48 and 200h of immersion could be correlated to the formation of the Ca-P layer at the fiber surface. After this a faster decrease in light transmission was observed from 200 to ~425h in SBF. SEM analysis suggested that after 200h, the surface of the fiber was fully covered by a thin Ca-P layer which is likely to scatter light. For immersion times longer than ~425h, the thickness of the Ca-P layer increased and thus acted as a barrier to the dissolution process limiting further reduction in light transmission. The tracking of light transmission through the PBG fiber allowed monitoring of the fiber dissolution in vitro. These results are essential in developing new bioactive fiber sensors that can be used to monitor bioresponse in situ. Copyright © 2014 Elsevier B.V. All rights reserved.

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

    Energy Technology Data Exchange (ETDEWEB)

    Mariano Velez

    2008-03-31

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

  3. 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

  4. Structure and spectroscopy of rare earth – Doped lead phosphate glasses

    International Nuclear Information System (INIS)

    Pisarski, Wojciech A.; Żur, Lidia; Goryczka, Tomasz; Sołtys, Marta; Pisarska, Joanna

    2014-01-01

    Highlights: • Lead phosphate glasses doped with rare earth ions were prepared. • The local structure was examined using X-ray diffraction and spectroscopic methods. • Different structural phosphate groups are present in lead phosphate glasses. • The electron–phonon coupling strength and phonon energy of the glass host was determined. • Several observed emission bands are due to 4f–4f electronic transitions of rare earth ions. -- Abstract: Lead–gallium phosphate glasses doped with rare the earth ions (Eu 3+ , Dy 3+ , Tb 3+ , Er 3+ ) were synthesized. The structure of obtained glasses was examined by means of use: X-ray diffraction (XRD), nuclear magnetic resonance ( 207 Pb and 31 P NMR), fourier transform infrared (FT-IR) and Raman spectroscopy. In contrast to fully amorphous Ln-doped samples (Ln = Eu, Dy, Tb), in Er-doped sample the GaPO 4 crystalline phase was identified. It was found from the NMR, FT-IR and Raman spectroscopic techniques that, different structural phosphate groups were present in lead phosphate glasses. Based on absorption measurements, the UV–VIS cut-off wavelength for lead phosphate glass was determined and its value is close to 305 nm. Excitation and emission spectra of rare earths were also detected. From excitation spectra of Eu 3+ the electron–phonon coupling strength and phonon energy of the glass host were determined. Due to 4f 6 –4f 6 (Eu 3+ ), 4f 8 –4f 8 (Tb 3+ ), 4f 9 –4f 9 (Dy 3+ ) and 4f 11 –4f 11 (Er 3+ ) electronic transitions of trivalent rare earth ions several luminescence bands were stated

  5. Glass formation and structure of calcium antimony phosphate glasses and those doped with tellurium oxide

    Science.gov (United States)

    Li, Jun; Zhang, Yin; Nian, Shangjiu; Wu, Zhenning; Cao, Weijing; Zhou, Nianying; Wang, Danian

    2017-03-01

    An approximate glass-forming region in the P2O5-Sb2O3-CaO ternary system was determined. The properties and structure of two compositional series of (A) (75- x)P2O5- xSb2O3-25CaO ( x = 20, 25, 30, 35 mol%) and (B) 45P2O5-30Sb2O3-(25- x)CaO- xTeO2 ( x = 5, 10, 15, 20 mol%) were studied systematically. Thermal properties were investigated by means of differential scanning calorimetry (DSC). The densities of all samples were measured by Archimedes' method using distilled water as the immersion liquid. The water durability of the glasses was described by their dissolution rate (DR) in the distilled water at 90 °C for some time periods. Density, thermal stability and water durability were improved with the addition of Sb2O3 and TeO2. Structural studies were carried out by X-ray diffraction (XRD), infrared spectroscopy and Raman spectroscopy. The phosphate chain depolymerization occurred with the increase of Sb2O3 and the Q2 structural units transformed to the Q1 and Q0 structural units with the addition of TeO2.

  6. Spectral-luminescence properties of trivalent titanium in aluminum-sodium phosphate glass

    International Nuclear Information System (INIS)

    Sukhanov, S.B.; Batyaev, I.M.

    1992-01-01

    Since development of the first crystal laser, Al 2 O 3 crystals remain the most widely used in quantum electronics. In the present work, the aluminum-sodium phosphate glass, Al 2 O 3 -Na 2 O 3 -P 2 O 5 , was studied with different proportions of components. A luminescence medium is obtained based on phosphate glass doped by Ti 3+ ions with intense emission in the 700-900-nm spectral range. This glass is a promising lasing medium for tunable solid-state lasers. 12 refs., 2 figs

  7. Bulk solubility and speciation of plutonium(VI) in phosphate-containing solutions

    International Nuclear Information System (INIS)

    Weger, H.T.; Okajima, S.; Cunnane, J.C.; Reed, D.T.

    1992-01-01

    The solubility and speciation of Pu(VI) with phosphate as a function of pH was investigated to determine the ability of phosphate to act as an actinide getter. The general properties were first investigated and are reported here with the goal of performing more quantitative experiments in the future. Solubility was approached from oversaturation at initial pH = 4, 10 and 13.4. Absorption spectra were recorded, the solution filtered and the filtrate counted. Absorption spectra were obtained at varying phosphate concentrations and at pH of 2.7 to 11.9. The effect of complexation on the 833 mn Pu(VI) band was characterized. Evidence for three phosphate complexes was obtained for pH -5 to 10 -6 M Pu(VI) was measured in the filtrate at pH ≤ 10 that were passed through a 50 mn filter. Pu(VI) complexes with phosphate over hydroxide at pH ≤ 11.6, but at pH ≥ 11.9, only hydrolyzed Pu(VI) was detected. At pH = 12, the concentration of Pu(VI) was as high as 10 -4 M

  8. Lead-iron phosphate glass: a stable storage medium for high-level nuclear waste

    International Nuclear Information System (INIS)

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

    1984-01-01

    Results are presented which show that lead-iron phosphate glasses are a promising new waste form for the safe immobilization of both high-level defense and high-level commercial radioactive waste. Relative to the borosilicate nuclear waste glasses that are currently the ''reference'' waste form for the long-term disposal of nuclear waste, lead-iron phosphate glasses have several distinct advantages: (1) an aqueous corrosion rate that is about 1000 times lower, (2) a processing temperature that is 100 0 to 250 0 C lower and, (3) a much lower melt viscosity in the temperature range from 800 0 to 1000 0 C. Most significantly, the lead-iron phosphate waste form can be processed using a technology similar to that developed for borosilicate nuclear waste glasses

  9. Novel resorbable glass-ceramic scaffolds for hard tissue engineering: from the parent phosphate glass to its bone-like macroporous derivatives.

    Science.gov (United States)

    Bretcanu, Oana; Baino, Francesco; Verné, Enrica; Vitale-Brovarone, Chiara

    2014-05-01

    One of the major challenges of hard tissue engineering research focuses on the development of scaffolds that can match the mechanical properties of the host bone and resorb at the same rate as the bone is repaired. The aim of this work was the synthesis and characterization of a resorbable phosphate glass, as well as its application for the fabrication of three dimensional (3-D) scaffolds for bone regeneration. The glass microstructure and behaviour upon heating were analysed by X-ray diffraction, differential scanning calorimetry and hot stage microscopy. The glass solubility was investigated according to relevant ISO standards using distilled water, simulated body fluid (SBF) and Tris-HCl as testing media. The glass underwent progressive dissolution over time in all three media but the formation of a hydroxyapatite-like layer was also observed on the samples soaked in SBF and Tris-HCl, which demonstrated the bioactivity of the material. The glass powder was used to fabricate 3-D macroporous bone-like glass-ceramic scaffolds by adopting polyethylene particles as pore formers: during thermal treatment, the polymer additive was removed and the sintering of glass particles was allowed. The obtained scaffolds exhibited high porosity (87 vol.%) and compressive strength around 1.5 MPa. After soaking for 4 months in SBF, the scaffolds mass loss was 76 wt.% and the pH of the solution did not exceed the 7.55 value, thereby remaining in a physiological range. The produced scaffolds, being resorbable, bioactive, architecturally similar to trabecular bone and exhibiting interesting mechanical properties, can be proposed as promising candidates for bone repair applications.

  10. Ultrasonic and Thermal Properties of Borate and Phosphate Glasses Containing Bismuth and Lead

    International Nuclear Information System (INIS)

    Aziz, Sidek Hj. Abd.; Ahmad, Hamezan; Wahab, Zaidan A.; Sulaiman, Zainal Abidin; Talib, Zainal Abidin; Shaari, A. Halim; Senin, H. B.

    2007-01-01

    Systematic series of (B2O3,P2O5)-Bi2O3-PbO glasses have been successfully prepared by using the rapid quenching technique in which each oxide content changes for every series on the basis of its weight percentage. Their amorphous natures were confirmed earlier by the x-ray diffraction technique. The experimental results show that the density of both glasses, determined by using the Archimedes principle, increases with the glass modifier content. This is due to the replacement of Bi2O3 and PbO in the borate and phosphate glassy networks. The molar volume for borate glass increases with the addition of bismuth and lead oxides, but a reverse trend occurs for the phosphate glass. The longitudinal and shear ultrasound velocities, determined by the MBS 8000 system, of both lead bismuth borate and phosphate glasses show a decreasing trend as more PbO and Bi2O3 are added to the glass system. The increase in PbO/Bi2O3 content was probably related to the progressive increase in the concentration of non-bridging oxygen (NBOs). Thermal studies of the glass, using the Labsys DTA-Setaram machine, show that the value of the glass transition temperature (Tg) is closely related to the chemical bond in the system. In lead bismuth borate glasses, the addition of more Pb2+ and Bi3+ results in a more dominant ionic bond character in the system and hence decreases Tg of the sample. However, in lead bismuth phosphate glasses, the addition of Pb2+ and Bi3+ not only failed to weaken the covalent character in P-O-P bonds, but strengthened it further, leading to an increment in the values of Tg

  11. Solubilities of some hydrous REE phosphates with implications for diagenesis and sea water concentrations

    International Nuclear Information System (INIS)

    Jonasson, R.G.; Bancroft, G.M.; Nesbitt, H.W.

    1985-01-01

    Solubility product determinations suggest that the hydrous phosphates of the rare earths, REPO 4 .xH 2 O, are important in controlling the sea water REE concentrations. Two of these solids, rhabdophane, (P6 2 22) and 'hydrous xenotime', (I4 1 /amd), have been synthesized at 100 C via the acid hydrolysis of the respective REE pyrophosphate. The solubility products at infinite dilution were determined to be pK 0 = 24.5, (La at 25 C); 26.0, (Pr at 100 C); 25.7, (Nd at 100 C); and 25.5, (Er at 100 C). On the basis of calculations involving the reaction of Re 3+ with apatite to form the hydrous phosphate, the lanthanum concentration in sea water is predicted to be about 140 pmol/L. Laboratory experiments support the hypothesis that apatite is a substrate for reactions with dissolved REE. (author)

  12. Studies on the synthesis and characterization of cesium-containing iron phosphate glasses

    Science.gov (United States)

    Joseph, Kitheri; Govindan Kutty, K. V.; Chandramohan, P.; Vasudeva Rao, P. R.

    2009-02-01

    Isotopes of cesium and strontium can be utilized as radiation source for various industrial and medical applications after their separation from high level nuclear waste. However, these elements need to be immobilized in a suitable matrix. In the present work, a systematic approach has been made to immobilize inactive cesium into iron phosphate glass. Up to 36 mol% of Cs 2O has been loaded successfully without crystallization. The glass transition temperature of the cesium loaded glass was found to increase initially and then decrease as a function of Cs 2O content. Mössbauer studies show that the concentration of Fe 3+ ions in the cesium loaded glasses is >95%. Volatilization experiments at 1263 K show that the weight loss is >0.5% for a period of 4 h. The 36 mol% of Cs 2O loaded iron phosphate glass with high Fe 3+ content described in this paper is reported for the first time.

  13. Ferric oxide quantum dots in stable phosphate glass system and their magneto-optical study

    Energy Technology Data Exchange (ETDEWEB)

    Garaje, Sunil N.; Apte, Sanjay K. [Nanocomposite Group, Centre for Materials for Electronics Technology (C-MET), Department of Electronics and Information Technology (DeitY), Government of India, Panchawati, Off Pashan Road, Pune 411008 (India); Kumar, Ganpathy [Department of Electrical and Computer Engineering, Tennessee Technological University, 1 William L. Jones Drive, Cookeville, TN 38505 (United States); Panmand, Rajendra P.; Naik, Sonali D. [Nanocomposite Group, Centre for Materials for Electronics Technology (C-MET), Department of Electronics and Information Technology (DeitY), Government of India, Panchawati, Off Pashan Road, Pune 411008 (India); Mahajan, Satish M., E-mail: smahajan@tntech.edu [Department of Electrical and Computer Engineering, Tennessee Technological University, 1 William L. Jones Drive, Cookeville, TN 38505 (United States); Chand, Ramesh [Ministry of Communications and Information Technology, Department of Electronics and Information Technology (DeitY), Electronics Niketan, 6, CGO Complex, New Delhi 110003 (India); Kale, Bharat B., E-mail: bbkale@cmet.gov.in [Nanocomposite Group, Centre for Materials for Electronics Technology (C-MET), Department of Electronics and Information Technology (DeitY), Government of India, Panchawati, Off Pashan Road, Pune 411008 (India)

    2013-02-15

    Graphical abstract: We report synthesis of ferric oxide embedded low melting phosphate glass nanocomposite and also the effect of ferric oxide nanoparticles (NCs) content on the optical and magneto-optical properties of the glasses. Faraday rotation of the glass nanocomposites was measured and showed variation in Verdet constant with concentration of ferric oxide. Interestingly, the host glass itself showed fairly good Verdet constant (11.5°/T cm) and there is a threefold enhancement in the Verdet constant of ferric oxide quantum dot-glass nanocomposite. Highlights: ► We synthesize ferric oxide embedded low melting stable phosphate glass nanocomposite. ► Glasses doped with 0.25 and 2% ferric oxide show particle size in the range of 4–12 nm. ► The host phosphate glass itself shows fairly good Verdet constant (11.5°/T cm). ► Glasses doped with 0.25% ferric oxide show high Verdet constant (30.525°/T cm). ► The as synthesis glasses may have potential application in magneto optical devices. -- Abstract: Herein, we report the synthesis of ferric oxide embedded low melting phosphate glass nanocomposite and also the effect of ferric oxide nanoparticles content on the optical and magneto-optical properties of the glasses. The optical study clearly showed red shift in optical cut off with increasing ferric oxide concentration. The band gap of the host glass was observed to be 3.48 eV and it shifted to 3.14 eV after doping with ferric oxide. The glasses doped with 0.25 and 2% ferric oxide showed particle size of 4–6 nm and 8–12 nm, respectively. Faraday rotation of the glass nanocomposites was measured and showed variation in the Verdet constant as per increasing concentration of ferric oxide. Interestingly, the host glass itself showed fairly good Verdet constant (11.5°/T cm) and threefold enhancement was observed in the Verdet constant of ferric oxide quantum dot-glass nanocomposite.

  14. A model for phosphate glass topology considering the modifying ion sub-network

    DEFF Research Database (Denmark)

    Hermansen, Christian; Mauro, J.C.; Yue, Yuanzheng

    2014-01-01

    In the present paper we establish a temperature dependent constraint model of alkali phosphate glasses considering the structural and topological role of the modifying ion sub-network constituted by alkali ions and their non-bonding oxygen coordination spheres. The model is consistent with availa......In the present paper we establish a temperature dependent constraint model of alkali phosphate glasses considering the structural and topological role of the modifying ion sub-network constituted by alkali ions and their non-bonding oxygen coordination spheres. The model is consistent...... with available structural data by NMR and molecular dynamics simulation and dynamic data such glass transition temperature (Tg) and liquid fragility (m). Alkali phosphate glasses are exemplary systems for developing constraint model since the modifying cation network plays an important role besides the primary...... phosphate network. The proposed topological model predicts the changing trend of the Tg and m with increasing alkali oxide content for alkali phosphate glasses, including an anomalous minimum at around 20 mol% alkali oxide content. We find that the minimum in Tg and m is caused by increased connectivity...

  15. AN ALTERNATIVE HOST MATRIX BASED ON IRON PHOSPHATE GLASSES FOR THE VITRIFICATION OF SPECIALIZED WASTE FORMS

    International Nuclear Information System (INIS)

    Day, Delbert D.

    2000-01-01

    As mentioned above, the overall goal of this research project was to collect the scientific information essential to develop iron phosphate glass based nuclear wasteforms. The specific objectives of the project were: (1) Investigate the structure of binary iron phosphate glasses and it's dependence on the composition and melting atmosphere: Understand atomic arrangements and nature of the bonding. Establish structure-property relationships. Determine the compositions and melting conditions which optimize the critical properties of the base glass. (2) Understand the structure of iron phosphate wasteforms and it's dependence on the composition and melting atmosphere: Investigate how the waste elements are bonded and coordinated within the glass structure. Establish structure-property relationships for the waste glasses. Determine the compositions and melting atmosphere for which the critical properties of the waste forms would be optimum. (3) Determine the role(s) played by the valence states of iron ions and it's dependence on the composition and melting atmosphere: Understand the different roles of iron(II) and iron(III) ions in determining the critical properties of the base glass and the waste forms. Investigate how the iron valence and its significance depend on the composition and melting atmosphere. (4) Investigate glass forming and crystallization processes of the iron phosphate glasses and their waste forms: Understand the dependence of the glass forming and crystallization characteristics on overall glass composition and valence states of iron ions. Identify the products of devitrification and investigate the critical properties of these crystalline compounds which may adversely affect the chemical and physical properties of the waste forms

  16. Evaluation of lead-iron-phosphate glass as a high-level waste form

    International Nuclear Information System (INIS)

    Chick, L.A.; Bunnell, L.R.; Strachan, D.M.; Kissinger, H.E.; Hodges, F.N.

    1986-01-01

    The lead-iron-phosphate (Pb-Fe-P) nuclear waste glass developed at Oak Ridge National Laboratory (ORNL) was evaluated for its potential as an improvement over the current reference waste form, borosilicate (B-Si) glass. Vitreous Pb-Fe-P glass appears to have substantially better chemical durability than B-Si glass. However, severe crystallization leading to deteriorated chemical durability would result if this glass were poured into large canisters, as is presently done with B-Si glass. Cesium leach rates from this crystallized material are orders of magnitude greater than those from B-Si glass. Therefore, to realize the performance advantages of the Pb-Fe-P material in a nuclear waste form, it would be necessary to process it so that it is cooled rapidly, thus retaining its vitreous structure

  17. Effect of composition and temperature on the second harmonic generation in silver phosphate glasses

    Science.gov (United States)

    Konidakis, I.; Psilodimitrakopoulos, S.; Kosma, K.; Lemonis, A.; Stratakis, E.

    2018-01-01

    We herein employ nonlinear laser imaging microscopy to explicitly study the dynamics of second harmonic generation (SHG) in silver iodide phosphate glasses. While glasses of this family have gained extensive scientific attention over the years due to their superior conducting properties, considerably less attention has been paid to their unique nonlinear optical characteristics. In the present study, firstly, it is demonstrated that SHG signal intensity is enhanced upon increasing silver content due to the random formation of silver microstructures within the glass network. Secondly, the SHG temperature dynamics were explored near the glass transition temperature (Tg) regime, where significant glass relaxation phenomena occur. It is found that heating towards the Tg improves the SHG efficiency, whereas above Tg, the capacity of glasses to generate second harmonic radiation is drastically suppressed. The novel findings of this work are considered important in terms of the potential employment of these glasses for the realization of advanced photonic applications like optical-switches and wavelength conversion devices.

  18. Phosphate-solubility and phosphatase activity in Gangetic alluvial soil as influenced by organophosphate insecticide residues.

    Science.gov (United States)

    Majumder, Shyam Prasad; Das, Amal Chandra

    2016-04-01

    An experiment was conducted under laboratory conditions to investigate the effect of four organophosphate insecticides, viz. monocrotophos, profenophos, quinalphos and triazophos at their field application rates (0.75, 1.0, 0.5 and 0.6 kg a.i.ha(-1), respectively), on the growth and activities of phosphate solubilizing microorganisms in relation to availability of insoluble phosphates in the Gangetic alluvial soil of West Bengal, India. The proliferation of phosphate solubilizing microorganisms was highly induced with profenophos (38.3%), while monocrotophos exerted maximum stimulation (20.8%) towards the solubility of insoluble phosphates in soil. The phosphatase activities of the soil (both acid phosphatase and alkaline phosphatase) were significantly increased due to the incorporation of the insecticides in general, and the augmentation was more pronounced with quinalphos (43.1%) followed by profenophos (27.6%) for acid phosphatase, and with monocrotophos (25.2%) followed by profenophos (16.1%) for alkaline phosphatase activity in soil. The total phosphorus was highly retained by triazophos (19.9%) followed by monocrotophos (16.5%), while incorporation of triazophos and quinalphos manifested greater availability of water soluble phosphorus in soil. Copyright © 2015 Elsevier Inc. All rights reserved.

  19. Structural features of silver-doped phosphate glasses in zone of femtosecond laser-induced modification

    Energy Technology Data Exchange (ETDEWEB)

    Vasileva, A.A., E-mail: anvsilv@gmail.com [Saint-Petersburg State University, Institute of Chemistry, Saint-Petersburg (Russian Federation); Nazarov, I.A. [Saint-Petersburg State University, Department of Physics, Saint-Petersburg (Russian Federation); Olshin, P.K.; Povolotskiy, A.V. [Saint-Petersburg State University, Institute of Chemistry, Saint-Petersburg (Russian Federation); Sokolov, I.A. [St.Petersburg State Polytechnical University, St.Petersburg (Russian Federation); LTD “AtomTjazhMash”, St.Petersburg (Russian Federation); Manshina, A.A. [Saint-Petersburg State University, Institute of Chemistry, Saint-Petersburg (Russian Federation)

    2015-10-15

    Femtosecond (fs) laser writing of two-dimensional microstructures (waveguides) is demonstrated in bulk phosphate glasses doped with silver ions. Silver-content phosphate and silver-content niobium–phosphate glasses with high concentration of silver oxide 55 mol% were used as samples for fs laser writing. The chemical network structure of the synthesized samples is analyzed through Raman spectroscopy and was found to be strongly sensitive to Nb incorporation. It was found that the direct laser writing process enables not only reorganization of glass network, but also formation of color centers and silver nanoparticles that are revealed in appearance of luminescence signal and plasmon absorption. The process of NPs' formation is more efficient for Nb-phosphate glass, while color centers are preferably formed in phosphate glass. - Graphical abstract: Formation of silver NPs on the surface of 0.5Ag{sub 2}O–0.4P{sub 2}O{sub 5}–0,1Nb{sub 2}O{sub 5} glass induced by CW laser irradiation. - Highlights: • The structure of 0.5Ag{sub 2}O–0.1Nb{sub 2}O{sub 5}–0.4P{sub 2}O{sub 5} and 0.55Ag{sub 2}O–0.45P{sub 2}O{sub 5} glasses was investigated by Raman spectroscopy. • Fs laser writing induces formation of silver NPs in investigated glasses. • Surface plasmon resonance in the absorption spectra confirms the formation of NP. • The possibility of CW laser induced formation of silver NPs on the surface of sample with niobium is shown.

  20. Structural features of silver-doped phosphate glasses in zone of femtosecond laser-induced modification

    International Nuclear Information System (INIS)

    Vasileva, A.A.; Nazarov, I.A.; Olshin, P.K.; Povolotskiy, A.V.; Sokolov, I.A.; Manshina, A.A.

    2015-01-01

    Femtosecond (fs) laser writing of two-dimensional microstructures (waveguides) is demonstrated in bulk phosphate glasses doped with silver ions. Silver-content phosphate and silver-content niobium–phosphate glasses with high concentration of silver oxide 55 mol% were used as samples for fs laser writing. The chemical network structure of the synthesized samples is analyzed through Raman spectroscopy and was found to be strongly sensitive to Nb incorporation. It was found that the direct laser writing process enables not only reorganization of glass network, but also formation of color centers and silver nanoparticles that are revealed in appearance of luminescence signal and plasmon absorption. The process of NPs' formation is more efficient for Nb-phosphate glass, while color centers are preferably formed in phosphate glass. - Graphical abstract: Formation of silver NPs on the surface of 0.5Ag 2 O–0.4P 2 O 5 –0,1Nb 2 O 5 glass induced by CW laser irradiation. - Highlights: • The structure of 0.5Ag 2 O–0.1Nb 2 O 5 –0.4P 2 O 5 and 0.55Ag 2 O–0.45P 2 O 5 glasses was investigated by Raman spectroscopy. • Fs laser writing induces formation of silver NPs in investigated glasses. • Surface plasmon resonance in the absorption spectra confirms the formation of NP. • The possibility of CW laser induced formation of silver NPs on the surface of sample with niobium is shown

  1. A comparative property investigation of lithium phosphate glass ...

    Indian Academy of Sciences (India)

    2017-08-16

    Aug 16, 2017 ... However, MW processing of bulk glass is a relatively recent development and a ... candidates for nuclear waste immobilization [19]. Low refrac- ... one of the basic prototype glasses in solid-state electrolyte, because of its high ...

  2. Copper(II) oxide solubility behavior in aqueous sodium phosphate solutions at elevated temperatures

    International Nuclear Information System (INIS)

    Ziemniak, S.E.; Jones, M.E.; Combs, K.E.S.

    1990-02-01

    A platinum-lined, flowing autoclave facility is used to investigate the solubility behavior of copper(II) oxide (CuO) in aqueous sodium phosphate solutions at temperatures between 292 and 535 K. Copper solubilities are observed to increase continuously with temperature and phosphate concentration. The measured solubility is examined via a Cu(II) ion hydrolysis/complexing model and thermodynamic functions for the hydrolysis/complexing reactions are obtained from a least- squares analysis of the data. Altogether, thermochemical properties are established for five anionic complexes: Cu(OH) 3 - , Cu(OH) 4 = , Cu(OH) 2 (HPO 4 ) = , Cu(OH) 3 (H 2 PO 4 ) = , and Cu(OH) 2 (PO 4 ) ≡ . Precise thermochemical parameters are also derived for the Cu(OH) + hydroxocomplex based on CuO solubility behavior previously observed in pure water (*) at elevated temperatures. The relative ease of Cu(II) ion hydrolysis is such that Cu(OH) 3 - species become the preferred hydroxocomplex for pH ≥ 9.4. 20 refs., 8 figs., 6 tabs

  3. Phosphate content influence on structural, spectroscopic, and lasing properties of Er,Yb-doped potassium-lanthanum phosphate glasses

    Czech Academy of Sciences Publication Activity Database

    Šulc, J.; Švejkar, R.; Jelínková, H.; Nejezchleb, K.; Nitsch, Karel; Cihlář, Antonín; Král, Robert; Ledinský, Martin; Fejfar, Antonín; Rodová, Miroslava; Zemenová, Petra; Nikl, Martin

    2016-01-01

    Roč. 55, č. 4 (2016), 1-10, č. článku 047102. ISSN 0091-3286 R&D Projects: GA ČR GAP204/12/0805 Institutional support: RVO:68378271 Keywords : erbium laser s * infrared laser s * laser materials modification * phosphate glass * diode -pumped eye-safe solid state laser Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 1.082, year: 2016

  4. Third-order nonlinearity of Er3+-doped lead phosphate glass

    Energy Technology Data Exchange (ETDEWEB)

    Santos, C. C. [Universidade Federal do Ceara, Ceara, Brazil; Guedes Da Silva, Ilde [ORNL; Siqueira, J. P. [Instituto de Física de São Carlos, Universidade de São Paulo, Brazil; Misoguti, L. [Instituto de Física de São Carlos, Universidade de São Paulo, Brazil; Zilio, S. C. [Instituto de Física de São Carlos, Universidade de São Paulo, Brazil; Boatner, Lynn A [ORNL

    2010-01-01

    The third-order optical susceptibility and dispersion of the linear refractive index of Er3+-doped lead phosphate glass were measured in the wavelength range between 400 and 1940 nm by using the spectrally resolved femtosecond Maker fringes technique. The nonlinear refractive index obtained from the third-order susceptibility was found to be five times higher than that of silica, indicating that Er3+-doped lead phosphate glass is a potential candidate to be used as the base component for the fabrication of photonic devices. For comparison purposes, the Z-scan technique was also employed to obtain the values of the nonlinear refractive index of E-doped lead phosphate glass at several wavelengths, and the values obtained using the two techniques agree to within 15%.

  5. Analysis of viscoelastic flow in tin phosphate glass

    International Nuclear Information System (INIS)

    Cha, Jaemin; Asida, Yuto; Takebe, Hiromichi

    2011-01-01

    The change of the viscoelastic flow near the imprinting temperature was analyzed by a penetration method with a commercial TMA and the result was compared with thermally-imprinted SnO-P 2 O 5 (SP) and SnO-B 2 O 3 -P 2 O 5 (SBP) glass samples by an imprint apparatus. The viscosity of SP glass increases monotonically with increasing SnO content and the specific movement is shown in viscoelastic flow under the optimized thermal imprinting temperature for SP glasses.

  6. Effect of the melting conditions on the properties of radiation color centers in lanthanum phosphate glasses

    Energy Technology Data Exchange (ETDEWEB)

    Karapetyan, G.O.; Rusan, V.V.; Yashchurzhinskaya, O.A.

    1986-01-01

    The authors investigate the spatial effects of ionizing radiation on the radiation processes in phosphate glasses to make a comparative estimate of the radiation yield from the radiation color centers (RCC) of different types. A study is made of their behavior under thermal decoloration. The results of a comparison of the integrated intensities of the ESR signal from trapping centers are given. The ESR spectrum of the glasses are presented--one differs slightly from the others. On the basis of the result of processing the ESR and optical spectra of gamma-irradiated lanthanum phosphate glasses synthesized under various conditions, the radiation yield of the RCC and the behavior of the intensity of their absorption under thermodecoloration are significantly affected by the conditions of synthesis of the glass.

  7. Biological performance of titania containing phosphate-based glasses for bone tissue engineering applications

    International Nuclear Information System (INIS)

    Abou Neel, Ensanya Ali; Chrzanowski, Wojciech; Knowles, Jonathan Campbell

    2014-01-01

    The interplay between glass chemistry, structure, degradation kinetics, and biological activity provides flexibility for the development of scaffolds with highly specific cellular response. The aim of this study was therefore to investigate the role of titania inclusion into the phosphate-based glass on its ability to stimulate osteoblast-like human osteosarcoma (HOS) cells to adhere, proliferate and differentiate. In depth morphological and biochemical characterisation was performed on HOS cells cultured on the surface of glass discs. Cell proliferation was also studied in the presence of the glass extract. Cell differentiation, through osteoblast phenotype genes, alkaline phosphatase (ALP) activity and osteocalcin production, was carried out using normal or osteogenic media. Both Thermanox® and titania free glass were used as controls. The data demonstrated that titania inclusion provides desired cytocompatible surface that supported initial cell attachment, sustained viability, and increased cell proliferation similar or significantly higher than Thermanox®. The modified glasses regulated osteoblastic cell differentiation as detected by osteoblast phenotype gene transcription and upregulated ALP and osteocalcin expression. Using osteogenic media had no significant effect on ALP activity and osteocalcin expression. Therefore, titania modified phosphate glasses may have future use as bone tissue engineering scaffolds. - Highlights: • This study investigated the role of titania on the biological response of phosphate glasses. • Incorporation of titania improved HOS cell attachment, viability and proliferation. • Titania modified glasses regulated osteoblastic cell differentiation. • Using osteogenic media had no significant effect on cell differentiation. • Titania modified glasses may have future use as bone tissue engineering scaffolds

  8. Mechanisms of postradiation transformations in alkaline-phosphate glasses activated by copper

    International Nuclear Information System (INIS)

    Vil'chinskaya, N.N.; Dmitryuk, A.V.; Ignat'ev, E.G.; Karapetyan, G.O.; Petrovskij, G.T.

    1984-01-01

    Lithium aluminophosphate glasses activated by copper served as the object under investigation. Copper content varied from 0 up to 0.13 mass.%. It is shown that pole redistribution among PO 4 2- and Cu(2) centers takes place in alkaline -phosphate glasses activated by Cu(1). This process prevails for copper content of above 0.1%. Therefore the possibility appears to evaluate the quantum yield of colour center formation

  9. Mechanisms of postradiation transformations in alkaline-phosphate glasses activated by copper

    Energy Technology Data Exchange (ETDEWEB)

    Vil' chinskaya, N.N.; Dmitryuk, A.V.; Ignat' ev, E.G.; Karapetyan, G.O.; Petrovskij, G.T. (Gosudarstvennyj Opticheskij Inst., Leningrad (USSR))

    1984-01-01

    Lithium aluminophosphate glasses activated by copper served as the object under investigation. Copper content varied from 0 up to 0.13 mass.%. It is shown that pole redistribution among PO/sub 4//sup 2 -/ and Cu(2) centers takes place in alkaline -phosphate glasses activated by Cu(1). This process prevails for copper content of above 0.1%. Therefore the possibility appears to evaluate the quantum yield of colour center formation.

  10. 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...

  11. Lead-iron phosphate glass as a containment medium for the disposal of high-level nuclear wastes

    Science.gov (United States)

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

    1984-04-11

    Disclosed are lead-iron phosphate glasses containing a high level of Fe/sub 2/O/sub 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

  12. Role of VAM on growth and phosphorus nutrition of maize with low soluble phosphate fertilization

    Directory of Open Access Journals (Sweden)

    Amitava Rakshit

    2010-01-01

    Full Text Available The effect of vesicular arbuscular mycorrhizal (VAM infection on growth and P nutrition in Maize (Zea mays, cv.DDH hybrid were assessed in Oxisol pot experiment. Maize was grown inoculated with spores of VAM fungi Glomus mosseae or non-inoculated. Low soluble ferrous phosphate (FePO4.4H2O was added to the mycorrhized and non-micrrohized maized. The dry weight of mycorrhized plants with added phosphate (P were higher than in mycorrhized plants without added P or non-mycorrhized plants with added P. The amount of P in the soil samples from pots with mycorrhizal plants fertilized with P was evidently smaller than those in samples also fertilized non-mycorrhizal plants. The percentage of P was higher in tissues of fertilized mycorrhial plants than in those mycorrihzed plants without or nonmycorrhized plants with added low-soluble P. These results indicated that plants in VAM symbiosis mobilize P better from low-soluble P than non-mycorrhized plants.

  13. Role of VAM on growth and phosphorus nutrition of maize with low soluble phosphate fertilization

    Directory of Open Access Journals (Sweden)

    Rakshit Amitava

    2010-03-01

    Full Text Available The effect of vesicular arbuscular mycorrhizal (VAM infection on growth and P nutrition in Maize (Zea mays, cv.DDH hybrid were assessed in Oxisol pot experiment. Maize was grown inoculated with spores of VAM fungi Glomus mosseae or non-inoculated. Low soluble ferrous phosphate (FePO4.4H2O was added to the mycorrhized and non-micrrohized maized. The dry weight of mycorrhized plants with added phosphate (P were higher than in mycorrhized plants without added P or non-mycorrhized plants with added P. The amount of P in the soil samples from pots with mycorrhizal plants fertilized with P was evidently smaller than those in samples also fertilized non-mycorrhizal plants. The percentage of P was higher in tissues of fertilized mycorrhial plants than in those mycorrihzed plants without or nonmycorrhized plants with added low-soluble P. These results indicated that plants in VAM symbiosis mobilize P better from low-soluble P than non-mycorrhized plants.

  14. Study of multicomponent fluoro-phosphate based glasses: Ho3+ as a luminescence center

    International Nuclear Information System (INIS)

    Babu, S.; Seshadri, M.; Balakrishna, A.; Reddy Prasad, V.; Ratnakaram, Y.C.

    2015-01-01

    The multicomponent 49.5P 2 O 5 –10AlF 3 –10BaF 2 –10SrF 2 –10PbO–10M (M=Li 2 O, Na 2 O, K 2 O, ZnO and Bi 2 O 3 ) glasses doped with 0.5 mol% holmium were prepared by melt quenching technique. Their thermal behavior was examined from differential scanning calorimetry (DSC). It is found that bismuth fluoro-phosphate glass matrix has good thermal stability. Their structures were characterized by the X-ray diffraction with SEM analysis, fourier transform infrared (FTIR), Raman spectroscopy and magic angle spinning (MAS) nuclear magnetic resonance (NMR) techniques. It was found that the phosphate network of these glasses was composed mainly of Q 2 and Q 3 phosphate tetrahedral units. The Judd–Ofelt parameters (J–O) (Ω 2 , Ω 4 and Ω 6 ) were evaluated from the intensities of the energy levels through optical absorption spectra. The most intense transitions are observed in the visible region of the spectrum. It is observed that the transition 5 I 8 → 5 G 6 is the hypersensitive transition for Ho 3+ ion. With these J–O parameters, various radiative properties like the probabilities of radiative transitions, radiative lifetimes and branching ratios have been calculated for different fluoro-phosphate glasses. The luminescence kinetics from excited holmium levels have been studied upon selective excitation through photoluminescence measurements. Holmium produces two visible laser emissions i.e. one is green ( 5 F 4 ( 5 S 2 )→ 5 I 8 ) and another one is red ( 5 F 5 → 5 I 8 ). The lifetimes of these levels have been experimentally determined through decay profile studies. The above results suggest that the prepared bismuth fluoro-phosphate glass system could be a suitable candidate for using it as a green laser source ( 5 F 4 ( 5 S 2 )→ 5 I 8 ) in the visible region of the spectrum. - Highlights: • Holmium doped different fluoro-phosphate glasses were prepared and characterized. • Structural, thermal and spectroscopic properties have been studied

  15. Infrared and Raman investigation of rare-earth phosphate glasses for potential use as radioactive waste forms

    International Nuclear Information System (INIS)

    Morgan, S.H.

    1989-01-01

    This project was designed to investigate the properties of the rare-earth phosphate glass systems CeO 2 -P 2 O 5 and Pr 2 O 3 -P 2 O 5 for potential use as radioactive waste glasses. The glass-forming region and optimum processing parameters of these glass systems were investigated. The structure of the host glasses and glassed loaded with simulated waste elements was investigated using Raman and infrared spectroscopy. Because of the radical differences in the spectra of the molybdenum-loaded glasses, the structure of the MoO 3 -P 2 O 5 glass system was also investigated. 29 refs., 8 figs., 2 tabs

  16. Effect of reducing conditions of synthesis on the character of the crystallization of phosphate glasses

    Energy Technology Data Exchange (ETDEWEB)

    Alekseeva, I.P.; Karapetyan, G.O.; Milyukov, E.M.; Rusan, V.V.

    1986-03-01

    The authors investigate the effect of synthesis conditions on the properties of phosphate glasses with a high concentration of rare-earth elements (REE) which are promising materials for quantum electronics. Particular attention was paid to the character of the crystallization of the glasses. A model glass of the composition La/sub 2/O/sub 3/ X 3P/sub 2/O/sub 5/ was studied which is transparent in the visible and near-IR regions of the spectrum and produced commercially.

  17. Demonstration of sulfur solubility determinations in high waste loading, low-activity waste glasses

    Energy Technology Data Exchange (ETDEWEB)

    Fox, K. M. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL)

    2016-04-25

    A method recommended by Pacific Northwest National Laboratory (PNNL) for sulfate solubility determinations in simulated low-activity waste glasses was demonstrated using three compositions from a recent Hanford high waste loading glass study. Sodium and sulfate concentrations in the glasses increased after each re-melting step. Visual observations of the glasses during the re-melting process reflected the changes in composition. The measured compositions showed that the glasses met the targeted values. The amount of SO3 retained in the glasses after washing was relatively high, ranging from 1.6 to 2.6 weight percent (wt %). Measured SnO2 concentrations were notably low in all of the study glasses. The composition of the wash solutions should be measured in future work to determine whether SnO2 is present with the excess sulfate washed from the glass. Increases in batch size and the amount of sodium sulfate added did not have a measureable impact on the amount of sulfate retained in the glass, although this was tested for only a single glass composition. A batch size of 250 g and a sodium sulfate addition targeting 7 wt %, as recommended by PNNL, will be used in future experiments.

  18. Copper solubility in DWPF, Batch 1 waste glass: Update report

    International Nuclear Information System (INIS)

    Schumacker, R.F.

    1992-01-01

    The ''Late Washing'' Step in the processing of precipitate will require the use of additional copper formate in the Precipitate Reactor to catalyze the hydrolysis reaction. The increased copper concentration in the melter feed increases the potential for metal precipitation during the vitrification of the melter feed. This report describes recent results with a conservative glass selected from the DWPF acceptable region in the Batch 1 Variability Study

  19. A Solid-State NMR Experiment: Analysis of Local Structural Environments in Phosphate Glasses

    Science.gov (United States)

    Anderson, Stanley E.; Saiki, David; Eckert, Hellmut; Meise-Gresch, Karin

    2004-01-01

    An experiment that can be used to directly study the local chemical environments of phosphorus in solid amorphous materials is demonstrated. The experiment aims at familiarizing the students of chemistry with the principles of solid-state NMR, by having them synthesize a simple phosphate glass, and making them observe the (super 31)P NMR spectrum,…

  20. Optical bistability in Er-Yb codoped phosphate glass microspheres at room temperature

    NARCIS (Netherlands)

    Warda, Jonathan M.; O'Shea, Danny G.; Shortt, Brian J.; Chormaic, Sile Nic

    2007-01-01

    We experimentally demonstrate optical bistability in Er(3+)-Yb(3+) phosphate glass microspheres at 295 K. Bistability is associated with both Er(3+) fluorescence and lasing behavior, and chromatic switching. The chromatic switching results from an intrinsic mechanism exploiting the thermal coupling

  1. Modeling of excimer laser radiation induced defect generation in fluoride phosphate glasses

    International Nuclear Information System (INIS)

    Natura, U.; Ehrt, D.

    2001-01-01

    Fluoride phosphate (FP) glasses with low phosphate content are high-transparent in the deep ultraviolet (UV) range and attractive candidates for UV-optics. Their optical properties are complementary to fluoride crystals. The anomalous partial dispersion makes them desirable for optical lens designs to reduce the secondary spectrum. Their UV transmission is limited by trace impurities introduced by raw materials and decreases when exposed to UV-radiation (lamps, lasers). The experiments of the paper published previously in this journal were used in order to separate radiation induced absorption bands in the fluoride phosphate glass FP10. In this paper the generation mechanism of the phosphorus-oxygen related hole center POHC 2 is investigated in detail in glasses of various compositions (various phosphate and impurity contents) in order to predict the transmission loss in case of long-time irradiation. Experiments were carried out using ArF- and KrF-excimer lasers (ns-pulses). POHC 2 generation strongly depends on the phosphate content and on the content of Pb 2+ . A model was developed on these terms. Rate equations are formulated, incorporating the influence of the Pb 2+ -content on the defect generation, a two-step creation term including an energy transfer process and a one-photon bleaching term. This results in a set of coupled nonlinear differential equations. Absorption coefficients and lifetimes of the excited states were calculated as well. Experimental results compared well with the numerical analysis of the theoretical rate equations

  2. The effects of uranium oxide high-level waste on the structure of iron phosphate glasses

    International Nuclear Information System (INIS)

    Badyal, Y.

    1998-01-01

    Because of their unusually good chemical durability, iron phosphate glasses are a natural candidate for a nuclear waste disposal glass. We have studied the effects of UO 2 high-level waste on the structure of iron phosphate glasses with both neutron and high-energy x-ray diffraction using the GLAD instrument of the Intense Pulsed Neutron Source and the 1-BM bending magnet beamline of the Advanced Photon Source, respectively. The results of neutron scattering, which is mostly sensitive to correlations involving light atoms i.e. O-O, Fe-O and P-O, suggest the main structural features of the base glass are largely unaffected by the addition of UO 2 . The nearest-neighbor P-O, Fe-O and O-O peaks remain at the same position in real space and their intensities scale approximately with concentration. These findings are consistent with the earlier results of Raman scattering and EXAFS on the Fe-K edge wherein both cases the spectra remain similar to the base glass. High-energy x-ray scattering which is sensitive to correlations involving the heavier atoms and thus complements the neutron measurements, is also consistent with uranium occupying interstitial sites in the relatively undisturbed base glass structure. However, important questions remain as to the precise local structure and oxidation state of uranium in these glasses

  3. The effects of uranium on the structure of iron phosphate glasses

    International Nuclear Information System (INIS)

    Badyal, Y.; Karabulut, M.; Marasinghe, K.; Saboungi, M.L.; Haeffner, D.; Shastri, S.; Day, D.E.; Ray, C.S.

    1999-01-01

    Because of their high chemical durability and waste loading capacity, iron phosphate glasses are a natural candidate for a nuclear waste disposal medium. The authors have studied the effects of uranium on the structure of iron phosphate glasses with both neutron and high-energy x-ray diffraction. The results of neutron scattering, which is mostly sensitive to pair correlations involving light atoms, i.e., O-O, Fe-O and P-O, indicate the main structural features of the base glass are largely unaffected by the addition of UO 2 . The nearest-neighbor P-O, Fe-O and O-O peaks remain at the same position in real space and their intensities scale approximately with concentration. These findings are consistent with earlier results using Raman scattering and EXAFS on the Fe-K edge, where in both cases the spectra remain similar to the base glass. The results of high-energy x-ray scattering, which is sensitive to correlations involving the heavier atoms and thus complements the neutron measurements, are also consistent with the overall picture of uranium occupying interstitial sites in the relatively undisturbed base glass structure. Combining the neutron and x-ray data for a 10 mol% UO 2 glass suggests the intriguing possibility of a U 6+ uranyl ion configuration although further work is needed to establish the precise local structure and valence state of uranium in these glasses

  4. Sulfur Solubility Testing and Characterization of LAW Phase 1 Matrix Glasses

    Energy Technology Data Exchange (ETDEWEB)

    Fox, K. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL)

    2017-02-24

    In this report, the Savannah River National Laboratory (SRNL) provides chemical analysis results for a series of simulated low-activity waste (LAW) glass compositions. These data will be used in the development of improved sulfur solubility models for LAW glass. A procedure developed at Pacific Northwest National Laboratory (PNNL) for producing sulfur saturated melts (SSMs) was carried out at both SRNL and PNNL to fabricate the glasses characterized in this report. This method includes triplicate melting steps with excess sodium sulfate, followed by grinding and washing to remove unincorporated sulfur salts. The wash solutions were also analyzed as part of this study.

  5. Sulfur Solubility Testing and Characterization of Hanford LAW Phase 2, Inner Layer Matrix Glasses

    Energy Technology Data Exchange (ETDEWEB)

    Fox, K. M. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); Edwards, T. B. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); Caldwell, M. E. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); Riley, W. T. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL)

    2017-11-27

    In this report, the Savannah River National Laboratory (SRNL) provides chemical analyses and Product Consistency Test (PCT) results for a series of simulated low activity waste (LAW) glass compositions. A procedure developed at the Pacific Northwest National Laboratory (PNNL) for producing sulfur saturated melts (SSMs) was carried out at both SRNL and PNNL to fabricate the glasses characterized in this report. This method includes triplicate melting steps with excess sodium sulfate, followed by grinding and washing to remove unincorporated sulfur salts. The wash solutions were also analyzed as part of this study. These data will be used in the development of improved sulfur solubility models for LAW glass.

  6. Spectroscopic studies of copper doped alkaline earth lead zinc phosphate glasses

    Energy Technology Data Exchange (ETDEWEB)

    Sastry, S. Sreehari, E-mail: sreeharisastry@yahoo.com [Department of Physics, Acharya Nagarjuna University, Nagarjunanagar 522510 (India); Rao, B. Rupa Venkateswara [Department of Physics, Acharya Nagarjuna University, Nagarjunanagar 522510 (India); Department of Physics, V.R. Siddhartha Engineering College, Vijayawada 52007 (India)

    2014-02-01

    In this paper spectroscopic investigation of Cu{sup 2+} doped alkaline earth lead zinc phosphate glasses was done through the spectroscopic techniques like X-ray diffraction, Ultra Violet (UV) absorption Spectroscopy, Electron Paramagnetic Resonance (EPR – X band), Fourier Transform Infra Red (FTIR) and Raman Spectroscopy. Alkaline earth lead zinc phosphate glasses containing 0.1% copper oxide (CuO) were prepared by the melt quenching technique. Spectroscopic studies indicated that there is a greater possibility for the copper ions to exist in Cu{sup 2+} state in these glasses. The optical absorption spectra indicated that the absorption peak of Cu{sup 2+} is a function of composition. The maxima absorption peak was reported at 862 nm for strontium lead zinc phosphate glass. Bonding parameters were calculated for the optical and EPR data. All these spectral results indicated clearly that there are certain structural changes in the present glass system with different alkaline earth contents. The IR and Raman spectra noticed the breaking of the P–O–P bonds and creating more number of new P–O–Cu bonds.

  7. Spectroscopic studies of copper doped alkaline earth lead zinc phosphate glasses

    International Nuclear Information System (INIS)

    Sastry, S. Sreehari; Rao, B. Rupa Venkateswara

    2014-01-01

    In this paper spectroscopic investigation of Cu 2+ doped alkaline earth lead zinc phosphate glasses was done through the spectroscopic techniques like X-ray diffraction, Ultra Violet (UV) absorption Spectroscopy, Electron Paramagnetic Resonance (EPR – X band), Fourier Transform Infra Red (FTIR) and Raman Spectroscopy. Alkaline earth lead zinc phosphate glasses containing 0.1% copper oxide (CuO) were prepared by the melt quenching technique. Spectroscopic studies indicated that there is a greater possibility for the copper ions to exist in Cu 2+ state in these glasses. The optical absorption spectra indicated that the absorption peak of Cu 2+ is a function of composition. The maxima absorption peak was reported at 862 nm for strontium lead zinc phosphate glass. Bonding parameters were calculated for the optical and EPR data. All these spectral results indicated clearly that there are certain structural changes in the present glass system with different alkaline earth contents. The IR and Raman spectra noticed the breaking of the P–O–P bonds and creating more number of new P–O–Cu bonds

  8. Rhenium solubility in borosilicate nuclear waste glass: implications for the processing and immobilization of technetium-99.

    Science.gov (United States)

    McCloy, John S; Riley, Brian J; Goel, Ashutosh; Liezers, Martin; Schweiger, Michael J; Rodriguez, Carmen P; Hrma, Pavel; Kim, Dong-Sang; Lukens, Wayne W; Kruger, Albert A

    2012-11-20

    The immobilization of technetium-99 ((99)Tc) in a suitable host matrix has proven to be a challenging task for researchers in the nuclear waste community around the world. In this context, the present work reports on the solubility and retention of rhenium, a nonradioactive surrogate for (99)Tc, in a sodium borosilicate glass. Glasses containing target Re concentrations from 0 to 10,000 ppm [by mass, added as KReO(4) (Re(7+))] were synthesized in vacuum-sealed quartz ampules to minimize the loss of Re from volatilization during melting at 1000 °C. The rhenium was found as Re(7+) in all of the glasses as observed by X-ray absorption near-edge structure. The solubility of Re in borosilicate glasses was determined to be ~3000 ppm (by mass) using inductively coupled plasma optical emission spectroscopy. At higher rhenium concentrations, additional rhenium was retained in the glasses as crystalline inclusions of alkali perrhenates detected with X-ray diffraction. Since (99)Tc concentrations in a glass waste form are predicted to be wastes, assuming Tc as Tc(7+) and similarities between Re(7+) and Tc(7+) behavior in this glass system.

  9. Novel selenium containing boro-phosphate glasses: Preparation and structural study

    International Nuclear Information System (INIS)

    Ciceo-Lucacel, R.; Radu, T.; Ponta, O.; Simon, V.

    2014-01-01

    We synthesized a new boro-phosphate glass system with different %mol SeO 2 content by conventional melt quenching technique. All samples were obtained in a glassy state with the vitreous structure confirmed by X-ray diffraction analysis. Scanning electron microscopy (SEM) revealed some non-homogeneous domains on the glasses surface, and their tendency to link each other once the selenium oxide content increases. Energy-dispersive X-ray analysis (EDAX) indicated similar elemental composition in different regions of each sample. X-ray photoelectron spectroscopy (XPS) was used to determine the nature of chemical bonding and the elemental composition at the sample surfaces, and Fourier transform infrared (FT-IR) spectroscopy was used to determine the structural groups in the obtained glass structure. Based on FT-IR results, the glass structure at short range order consists mainly of small phosphate units such as pyrophosphate (i.e. P 2 O 7 4− dimmers or terminating groups at the end of phosphate chains) and some metaphosphate (i.e. PO 3 − middle groups in the phosphate chains) units. The boron atoms are mainly placed in three-coordinated sites in BØ 3 or BØ 2 O − units. A small contribution of BØ 4 − units was also detected from the FT-IR spectra of glasses. For SeO 2 content higher than 5 mol%, the modifier role of selenium ions is strongly reflected on the local structure dominated in this case by pyrophosphate units. - Highlights: • New P 2 O 5 -CaO-B 2 O 3 -SeO 2 glasses synthesized by conventional melt quenching method. • Evidences for the Se ions modifier role in the local structure by FT-IR and XPS. • Significant advances in understanding the structural properties of the new system

  10. Mechanical behaviour of degradable phosphate glass fibres and composites-a review.

    Science.gov (United States)

    Colquhoun, R; Tanner, K E

    2015-12-23

    Biodegradable materials are potentially an advantageous alternative to the traditional metallic fracture fixation devices used in the reconstruction of bone tissue defects. This is due to the occurrence of stress shielding in the surrounding bone tissue that arises from the absence of mechanical stimulus to the regenerating bone due to the mismatch between the elastic modulus of bone and the metal implant. However although degradable polymers may alleviate such issues, these inert materials possess insufficient mechanical properties to be considered as a suitable alternative to current metallic devices at sites of sufficient mechanical loading. Phosphate based glasses are an advantageous group of materials for tissue regenerative applications due to their ability to completely degrade in vivo at highly controllable rates based on the specific glass composition. Furthermore the release of the glass's constituent ions can evoke a therapeutic stimulus in vivo (i.e. osteoinduction) whilst also generating a bioactive response. The processing of these materials into fibres subsequently allows them to act as reinforcing agents in degradable polymers to simultaneously increase its mechanical properties and enhance its in vivo response. However despite the various review articles relating to the compositional influences of different phosphate glass systems, there has been limited work summarising the mechanical properties of different phosphate based glass fibres and their subsequent incorporation as a reinforcing agent in degradable composite materials. As a result, this review article examines the compositional influences behind the development of different phosphate based glass fibre compositions intended as composite reinforcing agents along with an analysis of different potential composite configurations. This includes variations in the fibre content, matrix material and fibre architecture as well as other novel composites designs.

  11. Studies on solubility, glass-adsorption, extraction and evaporation of DDT using 36Cl-DDT

    International Nuclear Information System (INIS)

    Duursma, E.K.; Vas, D.; Marchand, M.

    1974-01-01

    A series of experiments are reported to investigate the behaviour of DDT in seawater using 36 Cl-DDT to determine DDT solubility in seawater, its adsorption to walls of glass vessels, the reproductibility of DDT extraction from seawater by organic solvents and its volatility when brought to dryness from solution

  12. Subcritical crack growth in a phosphate laser glass

    Energy Technology Data Exchange (ETDEWEB)

    Crichton, S.N.; Tomozawa, M.; Hayden, J.S.; Suratwala, T.I.; Campbell, J.H.

    1999-11-01

    The rate of subcritical crack growth in a metaphosphate Nd-doped laser glass was measured using the double-cleavage-drilled compression (DCDC) method. The crack velocity is reported as a function of stress intensity at temperatures ranging from 296 to 573 K and in nitrogen with water vapor pressures ranging from 40 Pa (0.3 mmHg) to 4.7 x 10{sup 4} Pa (355 mmHg). The measured crack velocities follow region I, II, and III behavior similar to that reported for silicate glasses. A chemical and mass-transport-limited reaction rate model explains the behavior of the data except at high temperatures and high water vapor pressures where crack tip blunting is observed. Blunting is characterized to reinitiate slow crack growth at higher stresses. A dynamic crack tip blunting mechanism is proposed to explain the deviation from the reaction rate model.

  13. Structure and transport investigations on lithium-iron-phosphate glasses

    International Nuclear Information System (INIS)

    Banday, Azeem; Sharma, Monika; Murugavel, Sevi

    2016-01-01

    Cathode materials for Lithium Ion Batteries (LIB’s) are being constantly studied and reviewed especially in the past few decades. LiFePO_4 (LFP) is one of the most potential candidates in the pedigree of cathode materials and has been under extensive study ever since. In this work, we report the synthesis of amorphous analogs of crystallite LFP by conventional melt quenching method. Thermal study by using differential scanning calorimetry (DSC) was used to determine the glass transition T_g and crystallization T_c temperatures on the obtained glass sample Fourier transform infrared (FTIR) absorption spectroscopy is being used to investigate the structural properties of the glass sample. The intrinsic electrical conductivity measurements were done using broad-band impedance spectroscopy with wide different temperature ranges. The conduction mechanism is described by non-adiabatic small polaron hopping between nearest neighbors. Based on the obtained results, we suggest that the glassy LFP is more suitable cathode material as compared to its crystalline counterpart.

  14. Optical and structural characterization of rare earth doped niobium phosphate glasses

    International Nuclear Information System (INIS)

    Sene, F.F.; Martinelli, J.R.; Gomes, L.

    2004-01-01

    Phosphate glasses containing up to 45mol% of niobium were obtained. X-ray diffraction, infrared, Raman, and optical absorption spectroscopy were used to analyze those materials. The refractive index varies from 1.70 to 1.85 as the amount of Nb increases. Niobium phosphate glasses with optical transparence in the (400-2500nm) range were produced. The cut off varied from 342nm to 378nm as a function of the Nb concentration. The cut off is due to the charge transfer O 2 ->Nb 5+ . Glasses containing 10mol% of Nb 2 O 5 are the most promising materials to be used as rare-earth ions hosts because they are chemically resistant, and show optical transparency in the spectral range of visible to infrared. Doping the glasses with 1-5mol% of Er, Ho, Pr, and Yb ions does not change the glass structure, as measured by X-ray diffraction, infrared, and Raman spectroscopy. The fluorescence lifetimes were determined for Nd, Yb, and Er, and the absorption cross-section were determined for all ions. The energy transfer in co-doped Yb-Er system was measured, and the lifetime of excited states and the luminescence efficiency were determined to be 91% for the Er 4 I 11/2 level, in the Yb-Er co-doped glasses

  15. Comparative investigation on the spectroscopic properties of Pr3+-doped boro-phosphate, boro-germo-silicate and tellurite glasses

    Science.gov (United States)

    Zhang, Liaolin; Dong, Guoping; Peng, Mingying; Qiu, Jianrong

    We report on the spectroscopic properties of Pr3+-doped boro-phosphate, boro-germo-silicate and tellurite glasses. The stimulated absorption and emission cross sections were estimated. Only one emission at 596 nm and 605 nm is observed in Pr3+-doped boro-phosphate and boro-germo-silicate glasses, respectively, while three emissions at 605 nm, 612 nm and 645 nm are observed in Pr3+-doped tellurite glass when excited at 467 nm. The fluorescence lifetime at 600 nm in Pr3+-doped boro-phosphate, boro-germo-silicate and tellurite glasses is 137 μs, 73 μs and 51 μs, respectively. The emissions from Pr3+-doped boro-phosphate, boro-germo-silicate and tellurite glasses show different decay behaviors and can be well explained by multiphonon relaxation theory.

  16. A Review of Iron Phosphate Glasses and Recommendations for Vitrifying Hanford Waste

    Energy Technology Data Exchange (ETDEWEB)

    Delbert E. Ray; Chandra S. Ray

    2013-11-01

    This report contains a comprehensive review of the research conducted, world-wide, on iron phosphate glass over the past ~30 years. Special attention is devoted to those iron phosphate glass compositions which have been formulated for the purpose of vitrifying numerous types of nuclear waste, with special emphasis on the wastes stored in the underground tanks at Hanford WA. Data for the structural, chemical, and physical properties of iron phosphate waste forms are reviewed for the purpose of understanding their (a) outstanding chemical durability which meets all current DOE requirements, (b) high waste loadings which can exceed 40 wt% (up to 75 wt%) for several Hanford wastes, (c) low melting temperatures, can be as low as 900°C for certain wastes, and (d) high tolerance for “problem” waste components such as sulfates, halides, and heavy metals (chromium, actinides, noble metals, etc.). Several recommendations are given for actions that are necessary to smoothly integrate iron phosphate glass technology into the present waste treatment plans and vitrification facilities at Hanford.

  17. Fe++/Fe+++ concentration relationship and mechanical properties of phosphate glasses useful for wastes immobilization

    International Nuclear Information System (INIS)

    Garcia, D.A.; Prado, Miguel O.

    2007-01-01

    Under different melting conditions, glasses with different Fe(II)/Fe(III) concentration relationship were prepared within each type of glass 43Fe 2 O 3 -57P 2 O 5 and 33,33Fe 2 O 3 - 66,67P 2 O 5 . Using Moessbauer spectroscopy Fe(II)/Fe(III) concentration values were determined. Vickers and Knoop indentations were used for determining their hardness, toughness, Young modulus and brittleness. The same measurements were carried on some silicate and aluminosilicate glasses. Also Weibull statistics was done to determine the characteristics (Weibull modulus and and fracture probability) of glass fracture. We found that silicate glasses (SG) are harder than phosphate glasses (PG). Toughness values for PG, are in the same range than for SG, although for the same density exhibit larger values or smaller brittleness than silicate glasses. For one of the glasses it was found that the mechanical load P 0 needed for a fracture probability of 63% increases with the Fe(II) content. (author)

  18. Evaluation of lead-iron-phosphate glass as a high-level waste form

    International Nuclear Information System (INIS)

    Chick, L.A.; Bunnell, L.R.; Strachan, D.M.; Kissinger, H.E.; Hodges, F.N.

    1986-09-01

    The lead-iron-phosphate (Pb-Fe-P) glass developed at Oak Ridge National Laboratory was evaluated for its potential as an improvement over the current reference nuclear waste form, borosilicate (B-Si) glass. The evaluation was conducted as part of the Second Generation HLW Technology Subtask of the Nuclear Waste Treatment Program at Pacific Northwest Laboratory. The purpose of this work was to investigate possible alternatives to B-Si glass as second-generation waste forms. While vitreous Pb-Fe-P glass appears to have substantially better chemical durability than B-Si glass, severe crystallization or devitrification leading to deteriorated chemical durability would result if this glass were poured into large canisters as is the procedure with B-Si glass. Cesium leach rates from this crystallized material are orders of magnitude greater than those from B-Si glass. Therefore, to realize the potential performance advantages of the Pb-Fe-P material in a nuclear waste form, the processing method would have to cool the material rapidly to retain its vitreous structure

  19. The influence of SrO and CaO in silicate and phosphate bioactive glasses on human gingival fibroblasts.

    Science.gov (United States)

    Massera, J; Kokkari, A; Närhi, T; Hupa, L

    2015-06-01

    In this paper, we investigate the effect of substituting SrO for CaO in silicate and phosphate bioactive glasses on the human gingival fibroblast activity. In both materials the presence of SrO led to the formation of a CaP layer with partial Sr substitution for Ca. The layer at the surface of the silicate glass consisted of HAP whereas at the phosphate glasses it was close to the DCPD composition. In silicate glasses, SrO gave a faster initial dissolution and a thinner reaction layer probably allowing for a continuous ion release into the solution. In phosphate glasses, SrO decreased the dissolution process and gave a more strongly bonded reaction layer. Overall, the SrO-containing silicate glass led to a slight enhancement in the activity of the gingival fibroblasts cells when compared to the SrO-free reference glass, S53P4. The cell activity decreased up to 3 days of culturing for all phosphate glasses containing SrO. Whereas culturing together with the SrO-free phosphate glass led to complete cell death at 7 days. The glasses containing SrO showed rapid cell proliferation and growth between 7 and 14 days, reaching similar activity than glass S53P4. The addition of SrO in both silicate and phosphate glasses was assumed beneficial for proliferation and growth of human gingival fibroblasts due to Sr incorporation in the reaction layer at the glass surface and released in the cell culture medium.

  20. Phosphorus availability from phosphate rock and sewage sludge as influenced by the addition of water soluble phosphate fertilizer

    International Nuclear Information System (INIS)

    Zapata, F.; Zaharah, A.R.

    2002-01-01

    Phosphorus (P) inputs are required for sustainable agricultural production in most acid soils of the tropics and subtropics. Phosphate rocks (PR) and organic materials have been suggested as alternative P sources in these soils. Quantitative information on the P availability from sewage sludge (SL) is scanty. Methods to improve the effectiveness of PR such as partial acidulation and compaction with water-soluble P sources have been recommended. The objective of this greenhouse study was to evaluate the relative agronomic effectiveness (RAE) of Florida PR and sewage sludges (irradiated and non-irradiated) applied alone and in mixture with a water-soluble source (triple superphosphate, TSP) at two rates (50 and 150 mg P kg -1 soil). The 32 P isotope dilution technique was utilised to determine the proportion of P in the plant taken up from the P fertilizer treatments. Wheat was grown on an acid loamy sand Dystric Eutrocrepts and harvested 6 weeks after planting. Results on total P uptake and the RAE of the P fertilizer sources tested indicated that the addition of 50 mg P kg -1 soil as TSP was adequate in supplying P to the 6-week-old wheat plants as compared to PR and sewage sludge. Intermediate values were obtained for the mixtures. Similar responses were observed for the high P rate. For a given P rate, phosphorus uptake from PR and SL in presence of TSP was higher than P uptake from these sources alone, indicating an enhancement effect of TSP on the effectiveness of these non-readily available sources. With respect to P uptake from PR applied alone, the relative increases in P uptake from PR due to TSP influence were 52 and 67% for the low and high P rates, respectively. The relative increases in P uptake from SL due to TSP when compared to P uptake from SL alone were 102 and 59% for the low and high P rates of application. Application of a water-soluble P fertilizer together with a non-readily available P source shows an enhancement on the P uptake from the non

  1. Phosphorus availability from phosphate rock and sewage sludge as influenced by the addition of water soluble phosphate fertilizer

    Energy Technology Data Exchange (ETDEWEB)

    Zapata, F. [Soil and Water Management and Crop Nutrition Section, International Atomic Energy Agency, Vienna (Austria)]. E-mail: F.Zapata@iaea.org; Zaharah, A.R. [Department of Land Management, Universiti Putra Malaysia, Serdang, Selangor (Malaysia)

    2002-05-15

    Phosphorus (P) inputs are required for sustainable agricultural production in most acid soils of the tropics and subtropics. Phosphate rocks (PR) and organic materials have been suggested as alternative P sources in these soils. Quantitative information on the P availability from sewage sludge (SL) is scanty. Methods to improve the effectiveness of PR such as partial acidulation and compaction with water-soluble P sources have been recommended. The objective of this greenhouse study was to evaluate the relative agronomic effectiveness (RAE) of Florida PR and sewage sludges (irradiated and non-irradiated) applied alone and in mixture with a water-soluble source (triple superphosphate, TSP) at two rates (50 and 150 mg P kg{sup -1} soil). The {sup 32}P isotope dilution technique was utilised to determine the proportion of P in the plant taken up from the P fertilizer treatments. Wheat was grown on an acid loamy sand Dystric Eutrocrepts and harvested 6 weeks after planting. Results on total P uptake and the RAE of the P fertilizer sources tested indicated that the addition of 50 mg P kg{sup -1} soil as TSP was adequate in supplying P to the 6-week-old wheat plants as compared to PR and sewage sludge. Intermediate values were obtained for the mixtures. Similar responses were observed for the high P rate. For a given P rate, phosphorus uptake from PR and SL in presence of TSP was higher than P uptake from these sources alone, indicating an enhancement effect of TSP on the effectiveness of these non-readily available sources. With respect to P uptake from PR applied alone, the relative increases in P uptake from PR due to TSP influence were 52 and 67% for the low and high P rates, respectively. The relative increases in P uptake from SL due to TSP when compared to P uptake from SL alone were 102 and 59% for the low and high P rates of application. Application of a water-soluble P fertilizer together with a non-readily available P source shows an enhancement on the P

  2. Investigations of the luminescence of phosphate glasses with respect to their application as solid dosemeters

    International Nuclear Information System (INIS)

    Regulla, D.F.

    1977-03-01

    A comprehensive presentation of the luminescent properties of phosphate glass is worked out. The extensive investigations show an essential enlargement of the knowledge on the luminescence of phosphate glass existing hitherto. These results form the basis for a detailed discussion of the luminescence mechanism. By applying additional results of measurements concerning optical and paramagnetic absorption, enabling the access to the atomic effect, propositions were developed for models of absorption, excitation and luminous centers relevant for dosimetry for which Ag ++ was found to be the constituent determining the centers. The interpretation of the luminescence phenomena within the frame of these models leads to considerable corrections on the existing concepts. At the same time the comparability of Ag-doped phosphate glasses and alkali halogenides is shown with respect to their luminescence behaviour, and with it an argument for the existence of crystal-like short-order regions in the amorphous glass is provided. This result serves as a basis for a discussion of the centers in the band model. Further investigations dealt with the quantities of influence for the practical application of the dosemeter. By interpretation of these results explanations are given for the effect of irradiation and evaluation temperatures, of LET, the dose, and UV light on the measuring signal. The phenomenon of 'pre-dose', for which especially surface effects have been detected as cause, is discussed under the aspect of a boundary layer theory. (orig./HP) [de

  3. Praseodymium ion doped phosphate glasses for integrated broadband ion-exchanged waveguide amplifier

    Energy Technology Data Exchange (ETDEWEB)

    Shen, L.F. [School of Textile and Material Engineering, Dalian Polytechnic University, Dalian 116034 (China); Department of Electronic Engineering, City University of Hong Kong, Kowloon, Hong Kong (China); Chen, B.J. [Department of Electronic Engineering, City University of Hong Kong, Kowloon, Hong Kong (China); Lin, H., E-mail: lhai8686@yahoo.com [School of Textile and Material Engineering, Dalian Polytechnic University, Dalian 116034 (China); Department of Electronic Engineering, City University of Hong Kong, Kowloon, Hong Kong (China); Pun, E.Y.B. [Department of Electronic Engineering, City University of Hong Kong, Kowloon, Hong Kong (China)

    2015-02-15

    Highlights: • Effective near-infrared emission (1380-1525 nm) is observed in Pr{sup 3+}-doped phosphate glasses. • Effective bandwidth of {sup 1}D{sub 2} → {sup 1}G{sub 4} transition emission is obtained to be 124 nm. • Channel waveguides have been fabricated by K{sup +}-Na{sup +} ion-exchange method. • Pr{sup 3+}-doped phosphate glasses are promising in developing integrated broadband waveguide amplifier. - Abstract: Effective near-infrared emission covering the fifth optical telecommunication window (1380-1525 nm) has been observed in Pr{sup 3+}-doped phosphate (NMAP) glasses. Judd-Ofelt parameters Ω{sub 2} (6.38 × 10{sup −20} cm{sup 2}), Ω{sub 4} (20.30 × 10{sup −20} cm{sup 2}) and Ω{sub 6} (0.40 × 10{sup −20} cm{sup 2}) indicate a high inversion asymmetrical and strong covalent environment in the optical glasses. The effective bandwidth (Δλ{sub eff}) of the corresponding {sup 1}D{sub 2} → {sup 1}G{sub 4} transition emission is obtained to be 124 nm, and the maximum stimulated emission cross-section (σ{sub em-max}) at 1468 nm is derived to be 1.14 × 10{sup −20} cm{sup 2}. Channel waveguide was fabricated successfully by K{sup +}-Na{sup +} ion-exchange method with mode field diameter of 8.8 μm in the horizontal direction and 6.7 μm in the vertical direction. Broad effective bandwidth, large emission cross-section and perfect thermal ion-exchangeability indicate that Pr{sup 3+}-doped NMAP phosphate glasses are promising in developing integrated broadband waveguide amplifier, especially operating at E- and S-bands which belong to the fifth optical telecommunication window.

  4. Novel selenium containing boro-phosphate glasses: preparation and structural study.

    Science.gov (United States)

    Ciceo-Lucacel, R; Radu, T; Ponta, O; Simon, V

    2014-06-01

    We synthesized a new boro-phosphate glass system with different %mol SeO2 content by conventional melt quenching technique. All samples were obtained in a glassy state with the vitreous structure confirmed by X-ray diffraction analysis. Scanning electron microscopy (SEM) revealed some non-homogeneous domains on the glasses surface, and their tendency to link each other once the selenium oxide content increases. Energy-dispersive X-ray analysis (EDAX) indicated similar elemental composition in different regions of each sample. X-ray photoelectron spectroscopy (XPS) was used to determine the nature of chemical bonding and the elemental composition at the sample surfaces, and Fourier transform infrared (FT-IR) spectroscopy was used to determine the structural groups in the obtained glass structure. Based on FT-IR results, the glass structure at short range order consists mainly of small phosphate units such as pyrophosphate (i.e. P2O7(4-) dimmers or terminating groups at the end of phosphate chains) and some metaphosphate (i.e. PO3(-) middle groups in the phosphate chains) units. The boron atoms are mainly placed in three-coordinated sites in BØ3 or BØ2O(-) units. A small contribution of BØ4(-) units was also detected from the FT-IR spectra of glasses. For SeO2 content higher than 5mol%, the modifier role of selenium ions is strongly reflected on the local structure dominated in this case by pyrophosphate units. Copyright © 2014 Elsevier B.V. All rights reserved.

  5. Color tunability of Sm{sup 3+} doped antimony–phosphate glass phosphors showing broadband fluorescence

    Energy Technology Data Exchange (ETDEWEB)

    Xiao, P. [School of Textile and Material Engineering, Dalian Polytechnic University, Dalian 116034 (China); Zhang, J.J., E-mail: zhangjj@dlpu.edu.cn [School of Textile and Material Engineering, Dalian Polytechnic University, Dalian 116034 (China); Shen, L.F. [Department of Electronic Engineering and State Key Laboratory of Millimeter Waves, City University of Hong Kong, Tat Chee Avenue, Kowloon, Hong Kong (China); Wang, Z.Q. [School of Textile and Material Engineering, Dalian Polytechnic University, Dalian 116034 (China); Pun, E.Y.B. [Department of Electronic Engineering and State Key Laboratory of Millimeter Waves, City University of Hong Kong, Tat Chee Avenue, Kowloon, Hong Kong (China); Lin, H., E-mail: lhai8686@yahoo.com [School of Textile and Material Engineering, Dalian Polytechnic University, Dalian 116034 (China); Department of Electronic Engineering and State Key Laboratory of Millimeter Waves, City University of Hong Kong, Tat Chee Avenue, Kowloon, Hong Kong (China)

    2016-10-15

    Sm{sup 3+} doped multicomponent antimony phosphate (MSP) luminescent glasses were prepared and tunable white fluorescence has been investigated. Broad visible emission depending on excitation wavelength is validated to be dominated by discrepant Sb{sup 3+} emitting centers. Group of narrow emissions from Sm{sup 3+} is beneficial to adding yellow and red components in Sm{sup 3+} doped MSP glasses, which is strengthened by effective energy transfer from Sb{sup 3+} to Sm{sup 3+}. Excitation wavelength selection and Sm{sup 3+} concentration adjustment are two feasible routes to optimize luminescence color in Sm{sup 3+} doped MSP glasses and the color tunability of fluorescence indicates that amorphous Sm{sup 3+} doped MSP glass phosphors possess potential for ideal white light devices.

  6. Compositional Dependence of Solubility/Retention of Molybdenum Oxides in Aluminoborosilicate-Based Model Nuclear Waste Glasses.

    Science.gov (United States)

    Brehault, Antoine; Patil, Deepak; Kamat, Hrishikesh; Youngman, Randall E; Thirion, Lynn M; Mauro, John C; Corkhill, Claire L; McCloy, John S; Goel, Ashutosh

    2018-02-08

    Molybdenum oxides are an integral component of the high-level waste streams being generated from the nuclear reactors in several countries. Although borosilicate glass has been chosen as the baseline waste form by most of the countries to immobilize these waste streams, molybdate oxyanions (MoO 4 2- ) exhibit very low solubility (∼1 mol %) in these glass matrices. In the past three to four decades, several studies describing the compositional and structural dependence of molybdate anions in borosilicate and aluminoborosilicate glasses have been reported in the literature, providing a basis for our understanding of fundamental science that governs the solubility and retention of these species in the nuclear waste glasses. However, there are still several open questions that need to be answered to gain an in-depth understanding of the mechanisms that control the solubility and retention of these oxyanions in glassy waste forms. This article is focused on finding answers to two such questions: (1) What are the solubility and retention limits of MoO 3 in aluminoborosilicate glasses as a function of chemical composition? (2) Why is there a considerable increase in the solubility of MoO 3 with incorporation of rare-earth oxides (for example, Nd 2 O 3 ) in aluminoborosilicate glasses? Accordingly, three different series of aluminoborosilicate glasses (compositional complexity being added in a tiered approach) with varying MoO 3 concentrations have been synthesized and characterized for their ability to accommodate molybdate ions in their structure (solubility) and as a glass-ceramic (retention). The contradictory viewpoints (between different research groups) pertaining to the impact of rare-earth cations on the structure of aluminoborosilicate glasses are discussed, and their implications on the solubility of MoO 3 in these glasses are evaluated. A novel hypothesis explaining the mechanism governing the solubility of MoO 3 in rare-earth containing aluminoborosilicate

  7. Sol-Gel Synthesis of Phosphate-Based Glasses for Hydrophilic Enamel Applications

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Dae-Sung; Ryu, Bong-ki [Pusan National University, Busan (Korea, Republic of)

    2017-04-15

    In this study, quaternary phosphate-based sol-gel derived glasses were synthesized from a P{sub 2}O{sub 5}-CaO-Na{sub 2}O-TiO{sub 2} system with a high TiO{sub 2} content of up to 50 mol%. The sol-gel method was chosen because incorporating a high percentage of titanium into a phosphate network via traditional melt-quench methods is non-trivial. The structure and thermal properties of the obtained stabilized sol-gel glasses were characterized using X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy, and differential scanning calorimetry (DSC). The XRD results confirmed the amorphous nature of all of the stabilized sol–gel derived glasses. The FTIR results revealed that added TiO{sub 2} enters the network as (TiO{sub 6}), which likely acts as a modifier oxide. Consequently, the number of terminal oxygen atoms increases, leading to an increase in the number of P-OH bonds. In addition, DSC results confirmed a decrease in glass transition and crystallization temperatures with increasing TiO{sub 2} content. This is the first report of a sol-gel synthesis strategy combined with enameling to prepare glass at low processing temperatures and the first use of such a system for both hydrophilic and chemical resistance purposes.

  8. Sol-Gel Synthesis of Phosphate-Based Glasses for Hydrophilic Enamel Applications

    International Nuclear Information System (INIS)

    Kim, Dae-Sung; Ryu, Bong-ki

    2017-01-01

    In this study, quaternary phosphate-based sol-gel derived glasses were synthesized from a P 2 O 5 -CaO-Na 2 O-TiO 2 system with a high TiO 2 content of up to 50 mol%. The sol-gel method was chosen because incorporating a high percentage of titanium into a phosphate network via traditional melt-quench methods is non-trivial. The structure and thermal properties of the obtained stabilized sol-gel glasses were characterized using X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy, and differential scanning calorimetry (DSC). The XRD results confirmed the amorphous nature of all of the stabilized sol–gel derived glasses. The FTIR results revealed that added TiO 2 enters the network as (TiO 6 ), which likely acts as a modifier oxide. Consequently, the number of terminal oxygen atoms increases, leading to an increase in the number of P-OH bonds. In addition, DSC results confirmed a decrease in glass transition and crystallization temperatures with increasing TiO 2 content. This is the first report of a sol-gel synthesis strategy combined with enameling to prepare glass at low processing temperatures and the first use of such a system for both hydrophilic and chemical resistance purposes.

  9. Immobilisation of radio cesium loaded ammonium molybdo phosphate in glass matrices

    International Nuclear Information System (INIS)

    Yalmali, Vrunda S.; Singh, I.J.; Sathi Sasidharan, N.; Deshingkar, D.S.

    2004-11-01

    Long half life and easy availability from high level wastes make 137 Cesium most economical radiation source. High level liquid waste processing for 137 Cesium removal has become easier due to development of Cesium specific granulated ammonium molybdophosphate (AMP) composite. In such applications, resulting spent composite AMP itself represents high active solid waste and immobilization of these materials in cement may not be acceptable. Studies on immobilization of 137 Cs loaded AMP were taken up in order to achieve twin goals of increasing safety and minimizing processing costs of the final matrix. Studies indicated that phosphate modified sodium borosilicate SPNM glasses prepared under usual oxidizing conditions are not suitable for immobilization of 137 Cs loaded on AMP .Phosphate glasses containing Na 2 O, P 2 O 5 , B 2 O 3 , Fe 2 O 3 , Al 2 O 3 and SiO 2 as major constituents are capable of incorporating 6 to 8 % AMP. The Normalized Leach rates of these glasses for sodium, cesium, boron and silica are 10 -4 to 10 -6 gm/cm 2 /day which are comparable to or better than those reported for NBS glasses incorporating HLW. Homogeneity of the final matrix was confirmed by x-ray diffraction analysis. Further studies on characterization of these glasses would establish their acceptability. (author)

  10. The structure of phosphate glass biomaterials from neutron diffraction and 31P nuclear magnetic resonance data

    International Nuclear Information System (INIS)

    Pickup, D M; Ahmed, I; Guerry, P; Knowles, J C; Smith, M E; Newport, R J

    2007-01-01

    Neutron diffraction and 31 P nuclear magnetic resonance spectroscopy were used to probe the structure of phosphate glass biomaterials of general composition (CaO) 0.5-x (Na 2 O) x (P 2 O 5 ) 0.5 (x = 0, 0.1 and 0.5). The results suggest that all three glasses have structures based on chains of Q 2 phosphate groups. Clear structural differences are observed between the glasses containing Na 2 O and CaO. The P-O bonds to bridging and non-bridging oxygens are less well resolved in the neutron data from the samples containing CaO, suggesting a change in the nature of the bonding as the field strength of the cation increases Na + → Ca 2+ . In the (CaO) 0.5 (P 2 O 5 ) 0.5 glass most of the Ca 2+ ions are present in isolated CaO x polyhedra whereas in the (Na 2 O) 0.5 (P 2 O 5 ) 0.5 glass the NaO x polyhedra share edges leading to a Na-Na correlation. The results of the structural study are related to the properties of the (CaO) 0.4 (Na 2 O) 0.1 (P 2 O 5 ) 0.5 biomaterial

  11. Concentration dependent spectroscopic properties of Dy3+ ions doped boro-phosphate glasses

    Science.gov (United States)

    Mariyappan, M.; Marimuthu, K.

    2016-05-01

    Dy3+ ions doped boro-phosphate glasses have been synthesized by melt quenching method and characterized through FTIR, absorption and luminescence spectral measurements. The presence of various stretching and bending vibrations of different borate and phosphate groups were identified from the FTIR spectra. In order to examine the electronic band structure of the studied glasses, Optical energy gap (Eopt) and Urbach energy (ΔE) values were estimated from the absorption spectra. The Judd-Ofelt (JO) intensity parameters were calculated to examine the symmetry of the ligand environment around the Dy3+ ions site. The emission spectra exhibit two intense emission bands at around 482 nm (blue) and 574 nm (yellow) corresponding to the 4F9/2→6H15/2 and 4F9/2→6H13/2 transitions respectively. The emission spectra were characterized through Commission International d'Eclairage (CIE) 1931 chromaticity diagram to explore its suitability for WLED applications.

  12. Lithium-Ion Mobility in Quaternary Boro-Germano-Phosphate Glasses.

    Science.gov (United States)

    Moguš-Milanković, Andrea; Sklepić, Kristina; Mošner, Petr; Koudelka, Ladislav; Kalenda, Petr

    2016-04-28

    Effect of the structural changes, electrical conductivity, and dielectric properties on the addition of a third glass-former, GeO2, to the borophosphate glasses, 40Li2O-10B2O3-(50 - x)P2O5-xGeO2, x = 0-25 mol %, has been studied. Introduction of GeO2 causes the structural modifications in the glass network, which results in a continuous increase in electrical conductivity. Glasses with low GeO2 content, up to 10 mol %, show a rapid increase in dc conductivity as a result of the interlinkage of slightly depolymerized phosphate chains and negatively charged [GeO4](-) units, which enhances the migration of Li(+) ions. The Li(+) ions compensate these delocalized charges connecting both phosphate and germanium units, which results in reduction of both bond effectiveness and binding energy of Li(+) ions and therefore enables their hop to the next charge-compensating site. For higher GeO2 content, the dc conductivity increases slightly, tending to approach a maximum in Li(+) ion mobility caused by the incorporation of GeO2 units into phosphate network combined with conversion of GeO4 to GeO6 units. The strong cross-linkage of germanium and phosphate units creates heteroatomic P-O-Ge bonds responsible for more effectively trapped Li(+) ions. A close correspondence between dielectric and conductivity parameters at high frequencies indicates that the increase in conductivity indeed is controlled by the modification of structure as a function of GeO2 addition.

  13. Salt Solubility Products of Diprenorphine Hydrochloride, Codeine and Lidocaine Hydrochlorides and Phosphates – Novel Method of Data Analysis Not Dependent on Explicit Solubility Equations

    Directory of Open Access Journals (Sweden)

    Gergely Völgyi

    2013-12-01

    Full Text Available A novel general approach was described to address many of the challenges of salt solubility determination of drug substances, with data processing and refinement of equilibrium constants encoded in the computer program pDISOL-XTM. The new approach was illustrated by the determinations of the solubility products of diprenorphine hydrochloride, codeine hydrochloride and phosphate, lidocaine hydrochloride and phosphate at 25 oC, using a recently-optimized saturation shake-flask protocol.  The effects of different buffers (Britton-Robinson universal and Sörensen phosphate were compared. Lidocaine precipitates were characterized by X-ray powder diffraction (XRPD and polarization light microscopy. The ionic strength in the studied systems ranged from 0.25 to 4.3 M. Codeine (and possibly diprenorphine chloride were less soluble than the phosphates for pH > 2. The reverse trend was evident with lidocaine.  Diprenorphine saturated solutions showed departure from the predictions of the Henderson-Hasselbalch equation in alkaline (pH > 9 solutions, consistent with the formation of a mixed-charge anionic dimer.

  14. Investigation of structural transformations in surface layer of phosphate glasses incorporating radiactive wastes

    International Nuclear Information System (INIS)

    Aloj, A.S.; Kolycheva, T.I.; Trofimenko, A.V.; Shashukov, E.A.

    1985-01-01

    The objective of the paper was to clarify possibilities of detection of structural transformations initial stages on the surface of phosphate glasses using the method of infrared reflection spectroscopy. Phase composition of crystalline compounds formed in surface glass layer is determined by the method of X-ray diffraction. All experiments were performed using sodium alumophosphate glass comprising the model mixture of fission product of the following compostion (mass%): Na 2 O-22.0, Al 2 O 3 -14.0, P 2 O 5 -50.0, Fe 2 O 3 -3.5, Cs 2 O-3.5, SrO-3.0, Ln 2 O 3 -4.0, where Ln 2 O 3 is a mixture of cerium, lanthanum and europium oxides. Sample preparation were carried out by molten glass deposition on platinum forms 15mm in diameter and 4mm thick. Glasses were treated within the 600-400deg.C temperature range. Fixing of processes accompanied by structural transformations was accomplished the method of rapid cooling. It has been shown that phase transformations, taking place in investigated phosphate glasses under the action of heat, result in deterioration of chemical properties. Analysis of IR spectra has revealed that emergence of structural transformations in surface layer of investigated glasses results in variation of a ratio of 1060 and 1140cm - 1 reflection band intensities. Experimental dependences of the time of beginning of variation of 1060 and 1140cm - 1 bands relative intensity on temperature are presented. Insemilogarithmic coordinates this dependence has a straight line form within the 600-400 deg C temperature range and is desc ribed by the following formular: lg r=-7.41+5.70x10 3 x1/T, where r is the time of process beginning, h. Extrapolation of established to the region of low temperature is shown. Competence of such extrapolation may be confirmed in the course of further experiments

  15. Development of novel strontium containing bioactive glass based calcium phosphate cement.

    Science.gov (United States)

    D'Onofrio, A; Kent, N W; Shahdad, S A; Hill, R G

    2016-06-01

    The aim of this study was to investigate the effect on properties of increasing strontium substitution for calcium in bioactive glasses used as precursors for novel calcium phosphate cements. Glasses were produced by progressively substituting strontium for calcium. Cements were prepared by mixing the glass powder with Ca(H2PO4)2 powder with a 2.5% solution of Na2HPO4. Setting times and compressive strength were measured after 1h, 1 day, 7 days and 28 days immersion in Tris buffer solution. X-ray diffraction (XRD), Fourier transform infrared spectroscopy and radiopacity were measured and crystal morphology was assessed using scanning electron microscopy. A correlation between the phases formed, morphology of the crystallites, setting time and compressive strength were analyzed. Setting time increased proportionally with strontium substitution in the glass up to 25%, whereas for higher substitutions it decreased. Compressive strength showed a maximum value of 12.5MPa and was strongly influenced by the interlocking of the crystals and their morphology. XRD showed that the presence of strontium influenced the crystal phases formed. Octacalcium phosphate (Ca8H2(PO4)6·5H2O, OCP) was the main phase present after 1h and 1 day whereas after 28 days OCP was completely transformed to strontium-containing hydroxyapatite (SrxCa(10-x)(PO4)6(OH)2, SrHA). Radiopacity increased proportionally to strontium substitution in the glass. A novel method to develop a bone substitute forming in vitro SrHA as a final product by using a bioactive glass as a precursor was shown. These novel injectable bioactive glass cements are promising materials for dental and orthopedic applications. Further in vivo characterizations are being conducted. Copyright © 2016 Academy of Dental Materials. Published by Elsevier Ltd. All rights reserved.

  16. Nanoscale mechanochemical wear of phosphate laser glass against a CeO{sub 2} particle in humid air

    Energy Technology Data Exchange (ETDEWEB)

    Yu, Jiaxin, E-mail: yujiaxin@swust.edu.cn [Key Laboratory of Testing Technology for Manufacturing Process, Ministry of Education, Southwest University of Science and Technology, Mianyang 621010 (China); He, Hongtu; Zhang, Yafeng [Key Laboratory of Testing Technology for Manufacturing Process, Ministry of Education, Southwest University of Science and Technology, Mianyang 621010 (China); Hu, Hailong [Analysis and Testing Center, Southwest University of Science and Technology, Mianyang 621010 (China)

    2017-01-15

    Highlights: • Friction components of phosphate glass/CeO{sub 2} pair in humid air were quantified to understand the friction mechanism. • Severe nanoscale wear was directly observed by AFM topography on both phosphate glass and CeO{sub 2} particle in humid air. • The wearless behaviors of phosphate glass in vacuum were confirmed by the AFM phase image. • Capillary water bridge induced corrosion plays an important role in the mechanochemical wear of phosphate glass in air. - Abstract: Using an atomic force microscope, the friction and wear of phosphate laser glass against a CeO{sub 2} particle were quantitatively studied both in humid air and in vacuum, to reveal the water molecules induced mechanochemical wear mechanism of phosphate laser glass. The friction coefficient of the glass/CeO{sub 2} pair in air was found to be 5–7 times higher than that in vacuum due to the formation of a capillary water bridge at the friction interface, with a contribution of the capillary-related friction to the total friction coefficient as high as 65–79%. The capillary water bridge further induced a serious material removal of glass and CeO{sub 2} particle surfaces, while supplying both a local liquid water environment to corrode the glass surface and a high shearing force to assist the stretching of the Ce−O−P bond, accelerating the reaction between water and the glass/CeO{sub 2} pair. In vacuum, however, no discernable wear phenomena were observed, but the phase images captured by AFM tapping mode suggested the occurrence of potential strain hardening in the friction area of the glass surface.

  17. Protein-adsorption and Ca-phosphate formation on chitosan-bioactive glass composite coatings

    Science.gov (United States)

    Wagener, V.; Boccaccini, A. R.; Virtanen, S.

    2017-09-01

    In the last years, chitosan-bioactive glass (BG) composites have been developed and investigated as bioactive coatings for orthopedic applications. The increase of bioactivity occurs due to the stimulation of calcium-phosphate/hydroxyapatite formation on the surface while the coating is degrading. In the present work, protein adsorption and its influence on calcium-phosphate precipitation was studied for the first time on such composite coatings. The experiments involved coating of 316L stainless steel substrates with chitosan (Ch) and chitosan-bioactive glass (Ch-BG) and immersion of the coated samples in two different bovine serum albumin (BSA) containing solutions, namely DI H2O (with pH adjusted to about 7.2 with diluted NaOH) and simulated body fluid (SBF). In order to investigate the influence of protein adsorption on calcium-phosphate precipitation, samples were also immersed in DI H2O and in SBF without BSA. Samples were analyzed by scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS) and time-of-flight secondary ion mass spectrometry (ToF-SIMS). Surface analysis revealed that adsorption of BSA takes place on all studied samples and that protein adsorption is influenced by the presence of Ca2+ and PO43- ions. Bioactivity in the form of hydroxyapatite pre-stage formation is significantly increased on Ch-BG composite coating as compared with bare stainless steel surface. However, calcium-phosphate precipitation in SBF is reduced by the presence of BSA.

  18. Water-Soluble Cellulose Derivatives Are Sustainable Additives for Biomimetic Calcium Phosphate Mineralization

    Directory of Open Access Journals (Sweden)

    Andreas Taubert

    2016-10-01

    Full Text Available The effect of cellulose-based polyelectrolytes on biomimetic calcium phosphate mineralization is described. Three cellulose derivatives, a polyanion, a polycation, and a polyzwitterion were used as additives. Scanning electron microscopy, X-ray diffraction, IR and Raman spectroscopy show that, depending on the composition of the starting solution, hydroxyapatite or brushite precipitates form. Infrared and Raman spectroscopy also show that significant amounts of nitrate ions are incorporated in the precipitates. Energy dispersive X-ray spectroscopy shows that the Ca/P ratio varies throughout the samples and resembles that of other bioinspired calcium phosphate hybrid materials. Elemental analysis shows that the carbon (i.e., polymer contents reach 10% in some samples, clearly illustrating the formation of a true hybrid material. Overall, the data indicate that a higher polymer concentration in the reaction mixture favors the formation of polymer-enriched materials, while lower polymer concentrations or high precursor concentrations favor the formation of products that are closely related to the control samples precipitated in the absence of polymer. The results thus highlight the potential of (water-soluble cellulose derivatives for the synthesis and design of bioinspired and bio-based hybrid materials.

  19. Eu{sup 3+} emission in phosphate glasses with high UV transparency

    Energy Technology Data Exchange (ETDEWEB)

    Silva, G.H. [Laboratório de Espectroscopia de Materiais (LEM), Departamento de Física, Universidade Federal de Juiz de Fora, CEP 36036-900 Juiz de Fora, MG (Brazil); Anjos, V., E-mail: virgilio@fisica.ufjf.br [Laboratório de Espectroscopia de Materiais (LEM), Departamento de Física, Universidade Federal de Juiz de Fora, CEP 36036-900 Juiz de Fora, MG (Brazil); Bell, M.J.V. [Laboratório de Espectroscopia de Materiais (LEM), Departamento de Física, Universidade Federal de Juiz de Fora, CEP 36036-900 Juiz de Fora, MG (Brazil); Carmo, A.P. [Instituto Federal Fluminense-Campus Cabo Frio, CP 112015, CEP 28909-971 Cabo Frio, RJ (Brazil); Pinheiro, A.S.; Dantas, N.O. [Laboratório de Novos Materiais Isolantes e Semicondutores (LNMIS), Instituto de Física, Universidade Federal de Uberlândia, CP 593, CEP 38400-902 Uberlândia, MG (Brazil)

    2014-10-15

    We report a study of the phosphate glass PZABP (P{sub 2}O{sub 5}–ZnO–Al{sub 2}O{sub 3}–BaO–PbO) doped with europium (Eu{sup 3+}) in different concentrations. Absorption, photoluminescence and time resolved photoluminescence were used to investigate the influence of increasing Eu{sup 3+} concentrations. The present glass exhibits Eu{sup 3+} absorption bands in the ultraviolet region (about 300 nm) due to the high transparency of the system compared to other phosphate glasses. In this way, it was possible to obtain the Judd–Ofelt parameters from the emission and absorption spectra. Moreover, a strong red emission attributed to the transition {sup 5}D{sub 0}→{sup 7}F{sub 2} of Eu{sup 3+} (611 nm) was observed. It was found that the radiative lifetime and the quantum efficiency of the Eu{sup 3+} level, {sup 5}D{sub 0}, do not suffer a significant change as the concentration of Eu{sup 3+} ions increases. - Highlights: • UV transparent glass matrix is used for Eu{sup 3+} doping. • Judd–Ofelt parameters from the emission and absorption spectra were obtained. • Red emission attributed to the transition {sup 5}D{sub 0}→{sup 7}F{sub 2} of Eu{sup 3+} (611 nm) was observed.

  20. Atmospheric Processing of Volcanic Glass: Effects on Iron Solubility and Redox Speciation.

    Science.gov (United States)

    Maters, Elena C; Delmelle, Pierre; Bonneville, Steeve

    2016-05-17

    Volcanic ash from explosive eruptions can provide iron (Fe) to oceanic regions where this micronutrient limits primary production. Controls on the soluble Fe fraction in ash remain poorly understood but Fe solubility is likely influenced during atmospheric transport by condensation-evaporation cycles which induce large pH fluctuations. Using glass powder as surrogate for ash, we experimentally simulate its atmospheric processing via cycles of pH 2 and 5 exposure. Glass fractional Fe solubility (maximum 0.4%) is governed by the pH 2 exposure duration rather than by the pH fluctuations, however; pH 5 exposure induces precipitation of Fe-bearing nanoparticles which (re)dissolve at pH 2. Glass leaching/dissolution release Fe(II) and Fe(III) which are differentially affected by changes in pH; the average dissolved Fe(II)/Fetot ratio is ∼0.09 at pH 2 versus ∼0.18 at pH 5. Iron release at pH 2 from glass with a relatively high bulk Fe(II)/Fetot ratio (0.5), limited aqueous Fe(II) oxidation at pH 5, and possibly glass-mediated aqueous Fe(III) reduction may render atmospherically processed ash a significant source of Fe(II) for phytoplankton. By providing new insight into the form(s) of Fe associated with ash as wet aerosol versus cloud droplet, we improve knowledge of atmospheric controls on volcanogenic Fe delivery to the ocean.

  1. Development of phosphate glass microspheres containing holmium for selective internal radiotherapy

    International Nuclear Information System (INIS)

    Barros Filho, Eraldo Cordeiro

    2016-01-01

    The selective internal radiotherapy is an alternative for some kinds of cancer as the hepatocellular carcinoma (HCC) or primary liver cancer treatment. In this treatment, glass or polymer microspheres containing radionuclides inside their structure are introduced in the liver through hepatic artery and trapped at the arterioles that feed the tumor. In this work, the development of phosphate glasses containing holmium for production of microspheres and their application in Brazil are proposed. The developed glasses presented suitable chemical durability, density of 2,7(3) g/cm 3 , high thermal stability and the impurities contained therein do not preclude the treatment. The microspheres were produced by the flame method and the gravitational fall method, and were characterized by means of several techniques to evaluate shape, average particle size, activity and biocompatibility suitable for selective internal radiotherapy. Based in the main results, the submission to in vivo tests is proposed. (author)

  2. Influence of silver nanoparticles on the spectroscopic properties of Sm3+ doped boro-phosphate glasses

    Science.gov (United States)

    Suthanthirakumar, P.; Marimuthu, K.

    2016-05-01

    The Sm3+ doped novel boro-phosphate glasses containing silver nanoparticles (NPs) (SmBPxA) have been prepared following the melt quenching technique and their structural and spectroscopic behavior were studied through HR-TEM, optical absorption and photoluminescence spectral measurements. The TEM analysis validates the existence of Ag NPs with an average diameter of ~8 nm. The Surface plasmon resonance (SPR) band of silver NPs was found at around 600 nm from the absorption spectrum of the Sm3+ ions free glass sample. The optical band gap energy (Eopt) corresponding to the direct and indirect allowed transitions and the Urbach energy (ΔE) values were determined from the absorption spectral measurements. The luminescence intensity is found to get enhance when the Ag NPs were embedded along with the Sm3+ ions in the prepared glasses due to the local electric field effect around the rare earth (RE) ion site produced by the SPR of Ag NPs.

  3. Fluorescence properties of Yb3+-Er3+ co-doped phosphate glasses containing silver nanoparticles

    Science.gov (United States)

    Martínez Gámez, Ma A.; Vallejo H, Miguel A.; Kiryanov, A. V.; Licea-Jiménez, L.; Lucio M, J. L.; Pérez-García, S. A.

    2018-04-01

    Er3+-Yb3+ co-doped phosphate glasses containing silver nitrate (SN), were fabricated. Transmission electron microscopy (TEM) and x-ray photoelectron spectroscopy (XPS) analyses were used to evidence the nucleation and presence of silver nanoparticles (SNP). The basic parameters of the glasses were inspected by means of absorption and fluorescence spectra, and fluorescence lifetimes under excitation at 916 nm (in-band of Yb3+), and at 406 nm (in-band of surface plasmon resonance given by the presence of SNP). The spectra as well as estimates for the basic parameters defining the lasing/amplifying potential of the glasses were studied as a function of SN concentration. The experimental results indicate that by increasing the SN content an enhancement of Er3+/Yb3+ fluorescence takes place.

  4. Calcium phosphate glass-ceramics for bioactive coating on a β-titanium alloy

    International Nuclear Information System (INIS)

    Kasuga, T.; Nogami, M.; Niinomi, M.

    2003-01-01

    The formation of a porous coating is the decisive feature for the bio-compatibility of silica-free calcium phosphate glass ceramics on alloy surfaces like the β-Ti structured Ti-29Nb-13Ta-4.6Zr used in this work. The ceramic composition is highly important: 50CaO-40P 2 O 5 -7Na 2 O-3TiO 2 glass powder produces a pore-free coating unable to bind hydroxyapatite, whereas 60CaO-30P 2 O 5 -7Na 2 O-3TiO 2 glass incorporates pores from which a crystalline hydroxyapatite phase can grow over the surface from simulated body fluid (see Figure). (Abstract Copyright [2003], Wiley Periodicals, Inc.)

  5. Calcium phosphate glass-ceramics for bioactive coating on a {beta}-titanium alloy

    Energy Technology Data Exchange (ETDEWEB)

    Kasuga, T.; Nogami, M. [Graduate School of Engineering, Nagoya Institute of Technology, Gokiso-cho, Showa-ku, Nagoya 466-8555 (Japan); Niinomi, M. [Department of Production Systems Engineering, Toyohashi University of Technology, Tenpaku-cho, Toyohashi 441-8580 (Japan)

    2003-07-01

    The formation of a porous coating is the decisive feature for the bio-compatibility of silica-free calcium phosphate glass ceramics on alloy surfaces like the {beta}-Ti structured Ti-29Nb-13Ta-4.6Zr used in this work. The ceramic composition is highly important: 50CaO-40P{sub 2}O{sub 5}-7Na{sub 2}O-3TiO{sub 2} glass powder produces a pore-free coating unable to bind hydroxyapatite, whereas 60CaO-30P{sub 2}O{sub 5}-7Na{sub 2}O-3TiO{sub 2} glass incorporates pores from which a crystalline hydroxyapatite phase can grow over the surface from simulated body fluid (see Figure). (Abstract Copyright [2003], Wiley Periodicals, Inc.)

  6. Effect of phosphate-based glass fibre surface properties on thermally produced poly(lactic acid) matrix composites.

    Science.gov (United States)

    Mohammadi, Maziar Shah; Ahmed, Ifty; Muja, Naser; Rudd, Christopher D; Bureau, Martin N; Nazhat, Showan N

    2011-12-01

    Incorporation of soluble bioactive glass fibres into biodegradable polymers is an interesting approach for bone repair and regeneration. However, the glass composition and its surface properties significantly affect the nature of the fibre-matrix interface and composite properties. Herein, the effect of Si and Fe on the surface properties of calcium containing phosphate based glasses (PGs) in the system (50P(2)O(5)-40CaO-(10-x)SiO(2)-xFe(2)O(3), where x = 0, 5 and 10 mol.%) were investigated. Contact angle measurements revealed a higher surface energy, and surface polarity as well as increased hydrophilicity for Si doped PG which may account for the presence of surface hydroxyl groups. Two PG formulations, 50P(2)O(5)-40CaO-10Fe(2)O(3) (Fe10) and 50P(2)O(5)-40CaO-5Fe(2)O(3)-5SiO(2) (Fe5Si5), were melt drawn into fibres and randomly incorporated into poly(lactic acid) (PLA) produced by melt processing. The ageing in deionised water (DW), mechanical property changes in phosphate buffered saline (PBS) and cytocompatibility properties of these composites were investigated. In contrast to Fe10 and as a consequence of the higher surface energy and polarity of Fe5Si5, its incorporation into PLA led to increased inorganic/organic interaction indicated by a reduction in the carbonyl group of the matrix. PLA chain scission was confirmed by a greater reduction in its molecular weight in PLA-Fe5Si5 composites. In DW, the dissolution rate of PLA-Fe5Si5 was significantly higher than that of PLA-Fe10. Dissolution of the glass fibres resulted in the formation of channels within the matrix. Initial flexural strength was significantly increased through PGF incorporation. After PBS ageing, the reduction in mechanical properties was greater for PLA-Fe5Si5 compared to PLA-Fe10. MC3T3-E1 preosteoblasts seeded onto PG discs, PLA and PLA-PGF composites were evaluated for up to 7 days indicating that the materials were generally cytocompatible. In addition, cell alignment along the PGF

  7. Concentration effect on the spectroscopic behavior of Tb3+ ions in zinc phosphate glasses

    International Nuclear Information System (INIS)

    Kesavulu, C.R.; Almeida Silva, Anielle Christine; Dousti, M.R.; Dantas, Noelio Oliveira; Camargo, A.S.S. de; Catunda, Tomaz

    2015-01-01

    Zinc phosphate glasses (PZABPTb) in the compositional system: P 2 O 5 –ZnO–Al 2 O 3 –BaO–PbO doped with variable Tb 3+ concentrations (1–5 wt% Tb 2 O 3 ) were prepared and characterized through absorption, excitation, emission and intensity decay rate measurements. The Judd–Ofelt model has been adopted to evaluate the radiative properties of the 5 D 4 → 7 F 6–3 emission transitions. The effect of Tb 3+ ion concentration on the emissions from the 5 D 3,4 excited levels is discussed in detail. Analysis of the intensity decay curves corresponding to blue and green emissions from levels 5 D 3 and 5 D 4 , respectively, allowed determination of effective lifetimes, which confirmed the Tb 3+ ion concentration quenching of the blue emission in these glasses. The decay curves for the 5 D 3 level are found to be non-exponential in nature for all the studied concentrations due to ion–ion energy transfer through cross-relaxation. In an attempt to identify the origin of the energy transfer mechanism, the decay curves were well fitted to the Inokuti–Hirayama model for S=6, which indicates that the energy transfer process is of dipole–dipole type. The optical band gap energy (E opt ) has been evaluated taking into account the ultraviolet edge of absorption spectra. - Highlights: • Tb 3+ -doped zinc phosphate glasses have been prepared by melt quenching technique. • Spectroscopic parameters were evaluated using the Judd–Ofelt theory. • Effects of Tb 3+ concentration on luminescence of the glasses were studied. • Strong intense laser transition for Tb 3+ ion in PZABPTb glasses is 5 D 4 → 7 F 5 (0.54 μm). • PZABPTb glasses could be used in the development of green color display devices and solid state visible lasers

  8. Structural and spectroscopic characteristics of Eu3+-doped tungsten phosphate glasses

    Science.gov (United States)

    Dousti, M. Reza; Poirier, Gael Yves; de Camargo, Andrea Simone Stucchi

    2015-07-01

    Tungsten based phosphate glasses are interesting non-crystalline materials, commonly known for photochromic and electrochromic effects, but also promising hosts for luminescent trivalent rare earth ions. Despite very few reports in the literature, association of the host´s functionalities with the efficient emissions of the dopant ions in the visible and near-infrared spectra could lead to novel applications. This work reports the preparation and characterization of glasses with the new composition 4(Sb2O3)96-x(50WO3 50NaPO3)xEu2O3 where x = 0, 0.1, 0.25, 0.5 and 1.0 mol%, obtained by the melt quenching technique. The glasses present large density (∼4.6 g cm-3), high glass transition temperature (∼480 °C) and high thermal stability against crystallization. Upon excitation at 464 nm, the characteristic emissions of Eu3+ ions in the red spectral region are observed with high intensity. The Judd-Ofelt intensity parameters Ω2 = 6.86 × 10-20, Ω4 = 3.22 × 10-20 and Ω6 = 8.2 × 10-20 cm2 were calculated from the emission spectra and found to be higher than those reported for other phosphate glass compositions. An average excited state lifetime value of 1.2 ms, was determined by fitting the luminescence decay curves with single exponential functions and it is comparable or higher than those of other oxide glasses.

  9. Novel selenium containing boro-phosphate glasses: Preparation and structural study

    Energy Technology Data Exchange (ETDEWEB)

    Ciceo-Lucacel, R.; Radu, T., E-mail: teodora.radu@phys.ubbcluj.ro; Ponta, O.; Simon, V.

    2014-06-01

    We synthesized a new boro-phosphate glass system with different %mol SeO{sub 2} content by conventional melt quenching technique. All samples were obtained in a glassy state with the vitreous structure confirmed by X-ray diffraction analysis. Scanning electron microscopy (SEM) revealed some non-homogeneous domains on the glasses surface, and their tendency to link each other once the selenium oxide content increases. Energy-dispersive X-ray analysis (EDAX) indicated similar elemental composition in different regions of each sample. X-ray photoelectron spectroscopy (XPS) was used to determine the nature of chemical bonding and the elemental composition at the sample surfaces, and Fourier transform infrared (FT-IR) spectroscopy was used to determine the structural groups in the obtained glass structure. Based on FT-IR results, the glass structure at short range order consists mainly of small phosphate units such as pyrophosphate (i.e. P{sub 2}O{sub 7}{sup 4−} dimmers or terminating groups at the end of phosphate chains) and some metaphosphate (i.e. PO{sub 3}{sup −} middle groups in the phosphate chains) units. The boron atoms are mainly placed in three-coordinated sites in BØ{sub 3} or BØ{sub 2}O{sup −} units. A small contribution of BØ{sub 4}{sup −} units was also detected from the FT-IR spectra of glasses. For SeO{sub 2} content higher than 5 mol%, the modifier role of selenium ions is strongly reflected on the local structure dominated in this case by pyrophosphate units. - Highlights: • New P{sub 2}O{sub 5}-CaO-B{sub 2}O{sub 3}-SeO{sub 2} glasses synthesized by conventional melt quenching method. • Evidences for the Se ions modifier role in the local structure by FT-IR and XPS. • Significant advances in understanding the structural properties of the new system.

  10. Mechanical, degradation and cytocompatibility properties of magnesium coated phosphate glass fibre reinforced polycaprolactone composites.

    Science.gov (United States)

    Liu, Xiaoling; Hasan, Muhammad S; Grant, David M; Harper, Lee T; Parsons, Andrew J; Palmer, Graham; Rudd, Chris D; Ahmed, Ifty

    2014-11-01

    Retention of mechanical properties of phosphate glass fibre reinforced degradable polyesters such as polycaprolactone and polylactic acid in aqueous media has been shown to be strongly influenced by the integrity of the fibre/polymer interface. A previous study utilising 'single fibre' fragmentation tests found that coating with magnesium improved the fibre and matrix interfacial shear strength. Therefore, the aim of this study was to investigate the effects of a magnesium coating on the manufacture and characterisation of a random chopped fibre reinforced polycaprolactone composite. Short chopped strand non-woven phosphate glass fibre mats were sputter coated with degradable magnesium to manufacture phosphate glass fibre/polycaprolactone composites. The degradation behaviour (water uptake, mass loss and pH change of the media) of these polycaprolactone composites as well as of pure polycaprolactone was investigated in phosphate buffered saline. The Mg coated fibre reinforced composites revealed less water uptake and mass loss during degradation compared to the non-coated composites. The cations released were also explored and a lower ion release profile for all three cations investigated (namely Na(+), Mg(2+) and Ca(2+)) was seen for the Mg coated composite samples. An increase of 17% in tensile strength and 47% in tensile modulus was obtained for the Mg coated composite samples. Both flexural and tensile properties were investigated and a higher retention of mechanical properties was obtained for the Mg coated fibre reinforced composite samples up to 10 days immersion in PBS. Cytocompatibility study showed both composite samples (coated and non-coated) had good cytocompatibility with human osteosarcoma cell line. © The Author(s) 2014 Reprints and permissions: sagepub.co.uk/journalsPermissions.nav.

  11. Spectroscopic and radiative properties study of Nd3+ doped cadmium-phosphate glasses

    International Nuclear Information System (INIS)

    Mahmoud, K.H.

    2010-01-01

    A spectroscopic investigation is performed on Nd 3+ doped cadmium-phosphate glasses. The Judd-Ofelt analysis is applied to the glass system in order to evaluate their potential as both glass laser and amplifier materials. The phenomenological Judd-Ofelt parameters Ω (2) , Ω (4) , and Ω (6) are determined, their values are 4.80x10 -20 , 6.18x10 -20 , and 7.14x10 -20 cm -2 , respectively. The quality factor for glass system is 0.86. Predicted radiative decay rates and branching ratios of transitions from Nd 3+4 F 3/2 state to the 4 I J manifolds are determined and analyzed. The calculated lifetime of the 4 F 3/2 metastable state of Nd 3+ is 31 μs. The results showed that 4 F 3/2 to 4 I 11/2 transition, with fluorescence at 1056 nm, has the most potential for laser application. Photoluminescence up-conversion under excitation at 488 nm laser light exhibits three emission bands of Nd 3+ ions at 541 (green), 601 (orange), and 677 nm (red). These emission bands are assigned to 4 G 7/2 → 4 I 9/2 , 4 G 7/2 → 4 I 11/2 , and 4 G 7/2 → 4 I 13/2 transitions, respectively. Analysis of luminescence spectra enhances the use of glass system in optical displays, lasers, and optical memory devices.

  12. Mobilization and utilization of sparingly soluble phosphates by VA mycorrhizal fungus external hyphae I-32P indirectly labelling

    International Nuclear Information System (INIS)

    Yao Qing; Zhao Zijuan; Feng Gu; Li Xiaolin; Chen Baodong

    2000-01-01

    Red clover were grown in three-compartment boxes, and were inoculated with VA mycorrhizal fungus, Glomus mosseae. External hyphae were separated from root system by 30 μm pore size membrane. Phosphorus fertilizer indirectly labelled with 32 P and five kind of phosphates were applied in the hyphae compartment, and the ability of external hyphae to mobilize the sparingly soluble phosphates were evaluated. the results showed that external hyphae mobilized and up took Ca 2 -P, Ca 8 -P, Al-P, Fe.P, but not Ca 10 -P. The phosphorus uptake by clover from phosphates and the contribution of phosphates to clover phosphorus nutrition were ranked as Ca 2 -P > Ca 8 -P, Al-P > Fe-P

  13. VARIABILITY STUDY TO DETERMINE THE SOLUBILITY OF IMPURITIES IN PLUTONIUM-BEARING, LANTHANIDE BOROSILICATE GLASS

    Energy Technology Data Exchange (ETDEWEB)

    Fox, K; Elizabeth Hoffman, E; Charles Crawford, C; Tommy Edwards, T; David Best, D; James Marra, J

    2007-09-26

    This study focuses on the development of a compositional envelope that describes the retention of various impurities in lanthanide borosilicate (LaBS) glass for vitrification and immobilization of excess, defense-related plutonium. A limited amount of impurity data for the various plutonium sources is available and projections were made through analysis of the available information. These projections were used to define types and concentrations of impurities in the LaBS glass compositions to be fabricated and tested. Sixty surrogate glass compositions were developed through a statistically designed approach to cover the anticipated ranges of concentrations for several impurity species expected in the plutonium feeds. An additional four glass compositions containing actual plutonium oxide were selected based on their targeted concentrations of metals and anions. The glasses were fabricated and characterized in the laboratory and shielded cells facility to determine the degree of retention of the impurity components, the impact of the impurities on the durability of each glass, and the degree of crystallization that occurred, both upon quenching and slow cooling. Overall, the LaBS glass system appears to be very tolerant of most of the impurity types and concentrations projected in the plutonium waste stream. For the surrogate glasses, the measured CuO, Ga{sub 2}O{sub 3}, Na{sub 2}O, NiO, and Ta{sub 2}O{sub 5} concentrations fell very close to their target values across the ranges of concentrations targeted in this study for each of these components. The measured CaO and PbO concentrations were consistently higher than the targeted values. The measured Cr{sub 2}O{sub 3} and Fe{sub 2}O{sub 3} concentrations were very close to the targets except for the one highest targeted value for each of these components. A solubility limit may have been approached in this glass system for K{sub 2}O and MgO. The measured Cl{sup -}, F{sup -}, SeO{sub 2} and SO{sub 4}{sup 2

  14. Structure and Dynamics on Superionic Conducting Phosphate Glasses By Neutron Scattering

    International Nuclear Information System (INIS)

    Kartini, E.; Kennedy, S.J.; Itoh, K.; Arai, M.; Mezei, F.; Nakamura, M.

    2005-01-01

    Full text: A series of Neutron Diffraction and Inelastic scattering experiments have been performed on superionic conducting phosphate glasses, MX-MPO 3 (M=Ag; X=I,S) and AgI-Ag 2 S-AgPO 3 . These materials are used for solid state battery, due to high conductivity up to 10 -2 S.cm -1 at ambient temperature. The conductivity of the insulator glass AgPO 3 ∼ 10 -7 S.cm -1 . Interestingly, the structure factor S(Q) exhibits a prepeak at very low Q∼0.7 Aangstroem -1 related to the IRO ∼ 10-12 Aangstroem and the Radial Distribution Function gives an extra peak ∼ 2.8 Aangstroem -1 that corresponds to Ag-I correlation. The dynamic structure factor S(Q,ω), shows a Boson peak at low energy ∼ 2.5 meV that increases with composition and temperature. These behaviors seem to be universal for the AgI doped glasses, but the origin remains not well understood. Increasing mobility of the Ag ions, due to expansion of the phosphate network plays a dominant role on raising the ionic conductivity, prepeak and Boson peak. (authors)

  15. Quantum and dielectric confinements of sub-10 nm gold in dichroic phosphate glass nanocomposites

    International Nuclear Information System (INIS)

    Singh, Shiv Prakash; Nath, Mithun; Karmakar, Basudeb

    2014-01-01

    Blue shifts of the surface plasmon resonance band of sub-10 nm gold in dichroic phosphate glass nanocomposites are observed with increase in both size of gold nanoparticles and refractive index of the medium, which are contrary to the common trends. These phenomena have been enlightened with the electrodynamics theories (Mie and Drude models) and happened due to quantum and dielectric confinements. Nanocomposites have been synthesized by in-situ thermochemical reduction technique in reducing phosphate glass matrices. The plasmon bands are characterized by the UV–vis spectrophotometer, and shape and size of the nanogold by the transmission electron microscopy. All the nanocomposites are dichroic in nature. - Highlights: • We fabricated Au 0 embedded nanocomposites in P 2 O 5 –SnO–ZnO glass matrix. • Au 0 synthesized by a single step in-situ thermochemical reduction technique. • We have reported the blue shifts of the SPR band of sub-10 nm Au 0 NPs. • The optical property has been explained on the basis of electrodynamics theories

  16. Synthesis of 32P labelled phosphate sources with different solubility and their efficient s as fertilizers

    International Nuclear Information System (INIS)

    De Luca, Edgar Fernando; Boaretto, Antonio Enedi; Muraoka, Takashi

    1999-01-01

    The study was carried out at the Centro de Energia Nuclear na Agricultura, Universidade de Sao Paulo (CENA/USP), Brazil. With the objective to determine, by the isotopic tracer, the P recovery by rice (Oriza sativa) plants and eucalypt (Eucalyptus grandis) seedlings from the P sources with different solubilities, an experiment was carried out in greenhouse, using Quartzpsamment soil samples, which is very poor in P content. Monocalcium, bicalcium, and tricalcium phosphate, Ca(H2 32 PO4).H2O, CaH 32 PO4.2H2O and Ca3(32 PO4)2, respectively were obtained in laboratory. Their solubilities and the X-ray difratometry and differential thermal analysis comproved that the laboratory procedures were adequate for obtaining the desired compounds. These products were applied in the soil as fertilizers. Plants were harvested 60 days after growth period, digested and analysed for total P and 32 P counting through Cerenkov effect. The P recovery from the sources varied from 14.1% [Ca(H2 32 PO4).H2O] to 17.0% [CaH 32 PO4.2H2O] for eucalypt, and from 15.0% [Ca3(32 PO4)2] to 22.2% [CaH 32 PO4.2H2O] for rice. The rice plants showed better ability to absorb P from the laboratory prepared sources, but the eucalypt presented higher P nutritional efficiency index. The difference method, used for determining the P recovery, underestimated the eucalypt and rice plant ability to absorb this nutrient compared to the isotopic method

  17. Phosphate glass fibre scaffolds: Tailoring of the properties and enhancement of the bioactivity through mesoporous glass particles.

    Science.gov (United States)

    Novajra, G; Boetti, N G; Lousteau, J; Fiorilli, S; Milanese, D; Vitale-Brovarone, C

    2016-10-01

    Novel bone glass fibre scaffolds were developed by thermally bonding phosphate glass fibres belonging to the P2O5-CaO-Na2O-SiO2-MgO-K2O-TiO2 system (TiPS2.5 glass). Scaffolds with fibres of 85 or 110μm diameter were fabricated, showing compressive strength in the range of 2-3.5MPa, comparable to that of the trabecular bone. The effect of different thermal treatments and fibre diameters and length on the final scaffold structure was investigated by means of micro-CT analysis. The change of the sintering time from 30 to 60min led to a decrease in the scaffold overall porosity from 58 to 21vol.% for the 85μm fibre scaffold and from 50 to 40vol.% when increasing the sintering temperature from 490 to 500°C for the 110μm fibre scaffold. The 85μm fibres resulted in an increase of the scaffold overall porosity, increased pore size and lower trabecular thickness; the use of different fibre diameters allowed the fabrication of a scaffold showing a porosity gradient. In order to impart bioactive properties to the scaffold, for the first time in the literature the introduction in these fibre scaffolds of a bioactive phase, a melt-derived bioactive glass (CEL2) powder or spray-dried mesoporous bioactive glass particles (SD-MBG) was investigated. The scaffold bioactivity was assessed through soaking in simulated body fluid. CEL2/glass fibre scaffold did not show promising results due to particle detachment from the fibres during soaking in simulated body fluid. Instead the use of mesoporous bioactive powders showed to be an effective way to impart bioactivity to the scaffold and could be further exploited in the future through the ability of mesoporous particles to act as systems for the controlled release of drugs. Copyright © 2016 Elsevier B.V. All rights reserved.

  18. Incorporation of casein phosphopeptide-amorphous calcium phosphate into a glass-ionomer cement.

    Science.gov (United States)

    Mazzaoui, S A; Burrow, M F; Tyas, M J; Dashper, S G; Eakins, D; Reynolds, E C

    2003-11-01

    Casein phosphopeptide-amorphous calcium phosphate (CPP-ACP) nanocomplexes have been shown to prevent demineralization and promote remineralization of enamel subsurface lesions in animal and in situ caries models. The aim of this study was to determine the effect of incorporating CPP-ACP into a self-cured glass-ionomer cement (GIC). Incorporation of 1.56% w/w CPP-ACP into the GIC significantly increased microtensile bond strength (33%) and compressive strength (23%) and significantly enhanced the release of calcium, phosphate, and fluoride ions at neutral and acidic pH. MALDI mass spectrometry also showed casein phosphopeptides from the CPP-ACP nanocomplexes to be released. The release of CPP-ACP and fluoride from the CPP-ACP-containing GIC was associated with enhanced protection of the adjacent dentin during acid challenge in vitro.

  19. A statistically designed matrix to evaluate solubility, impurity tolerance, and thermal stability of plutonium-bearing glasses

    International Nuclear Information System (INIS)

    Peeler, D.K.; Meaker, T.F.; Edwards, T.B.; McIntyre, D.S.

    1997-01-01

    In support of the Department of Energy's (DOE) Office of Fissile Material Disposition (OFDM) Program, Westinghouse Savannah River Company (WSRC) is evaluating a unique lanthanide borosilicate glass to immobilize excess plutonium and other heavy metals. The lanthanide borosilicate (LaBS) glass system met all FY96 programmatic planning objectives. Those objectives were focused on (1) demonstrating 10 wt% Pu solubility, and (2) meeting preliminary product performance criteria. Although 10 wt% Pu solubility was demonstrated with product performance exceeding high level waste glasses based on PCT results, the LaBS system was not optimized

  20. Stressed waveguides with tubular depressed-cladding inscribed in phosphate glasses by femtosecond hollow laser beams.

    Science.gov (United States)

    Long, Xuewen; Bai, Jing; Zhao, Wei; Stoian, Razvan; Hui, Rongqing; Cheng, Guanghua

    2012-08-01

    We report on the single-step fabrication of stressed optical waveguides with tubular depressed-refractive-index cladding in phosphate glasses by the use of focused femtosecond hollow laser beams. Tubelike low index regions appear under direct exposure due to material rarefaction following expansion. Strained compacted zones emerged in domains neighboring the tubular track of lower refractive index, and waveguiding occurs mainly within the tube core fabricated by the engineered femtosecond laser beam. The refractive index profile of the optical waveguide was reconstructed from the measured transmitted near-field intensity.

  1. Micropatterning of nanocomposite polymer scaffolds using sacrificial phosphate glass fibers for tendon tissue engineering applications.

    Science.gov (United States)

    Alshomer, Feras; Chaves, Camilo; Serra, Tiziano; Ahmed, Ifty; Kalaskar, Deepak M

    2017-04-01

    This study presents a simple and reproducible method of micropatterning the novel nanocomposite polymer (POSS-PCU) using a sacrificial phosphate glass fiber template for tendon tissue engineering applications. The diameters of the patterned scaffolds produced were dependent on the diameter of the glass fibers (15 μm) used. Scaffolds were tested for their physical properties and reproducibility using various microscopy techniques. For the first time, we show that POSS-PCU supports growth of human tenocytes cells. Furthermore, we show that cellular alignment, their biological function and expression of various tendon related proteins such as scleraxis, collagen I and III, tenascin-C are significantly elevated on the micropatterned polymer surfaces compared to flat samples. This study demonstrated a simple, reproducible method of micropatterning POSS-PCU nanocomposite polymer for novel tendon repair applications, which when provided with physical cues could help mimic the microenvironment of tenocytes cells. Copyright © 2017 Elsevier Inc. All rights reserved.

  2. Higher Fe{sup 2+}/total Fe ratio in iron doped phosphate glass melted by microwave heating

    Energy Technology Data Exchange (ETDEWEB)

    Mandal, Ashis K., E-mail: ashis@cgcri.res.in [CSIR-Central Glass and Ceramic Research Institute, 196 Raja S.C. Mullick Road, Kolkata 700032 (India); Sinha, Prasanta K. [CSIR-Central Glass and Ceramic Research Institute, 196 Raja S.C. Mullick Road, Kolkata 700032 (India); Das, Dipankar [UGC-DAE Consortium for Scientific Research, Kolkata 700098 (India); Guha, Chandan [Department of Chemical Engineering, Jadavpur University, Kolkata 700032 (India); Sen, Ranjan [CSIR-Central Glass and Ceramic Research Institute, 196 Raja S.C. Mullick Road, Kolkata 700032 (India)

    2015-03-15

    Highlights: • Iron doped phosphate glasses prepared using microwave heating and conventional heating under air and reducing atmosphere. • Presence of iron predominantly in the ferrous oxidation state in all the glasses. • Significant concentrations of iron in the ferrous oxidation state on both octahedral and tetrahedral sites in all the glasses. • Ratio of Fe{sup 2+} with total iron is found higher in microwave prepared glasses in comparison to conventional prepared glasses. - Abstract: Iron doped phosphate glasses containing P{sub 2}O{sub 5}–MgO–ZnO–B{sub 2}O{sub 3}–Al{sub 2}O{sub 3} were melted using conventional resistance heating and microwave heating in air and under reducing atmosphere. All the glasses were characterised by UV–Vis–NIR spectroscopy, Mössbauer spectroscopy, thermogravimetric analysis and wet colorimetry analysis. Mössbauer spectroscopy revealed presence of iron predominantly in the ferrous oxidation state on two different sites in all the glasses. The intensity of the ferrous absorption peaks in UV–Vis–NIR spectrum was found to be more in glasses prepared using microwave radiation compared to the glasses prepared in a resistance heating furnace. Thermogravimetric analysis showed increasing weight gain on heating under oxygen atmosphere for glass corroborating higher ratio of FeO/(FeO + Fe{sub 2}O{sub 3}) in glass melted by direct microwave heating. Wet chemical analysis also substantiated the finding of higher ratio Fe{sup +2}/ΣFe in microwave melted glasses. It was found that iron redox ratio was highest in the glasses prepared in a microwave furnace under reducing atmosphere.

  3. Concentration effect on the spectroscopic behavior of Tb{sup 3+} ions in zinc phosphate glasses

    Energy Technology Data Exchange (ETDEWEB)

    Kesavulu, C.R., E-mail: crkesavulu2005@gmail.com [Instituto de Fisica de São Carlos, Universidade de São Paulo, Avenida Trabalhador Sãocarlense 400, São Carlos, SP (Brazil); Almeida Silva, Anielle Christine [Laboratorio de Novos Materials Isolantes e Semicondutores (LNMIS), Instituto de Física, Universidade Federal de Uberândia, MG (Brazil); Dousti, M.R. [Instituto de Fisica de São Carlos, Universidade de São Paulo, Avenida Trabalhador Sãocarlense 400, São Carlos, SP (Brazil); Dantas, Noelio Oliveira [Laboratorio de Novos Materials Isolantes e Semicondutores (LNMIS), Instituto de Física, Universidade Federal de Uberândia, MG (Brazil); Camargo, A.S.S. de; Catunda, Tomaz [Instituto de Fisica de São Carlos, Universidade de São Paulo, Avenida Trabalhador Sãocarlense 400, São Carlos, SP (Brazil)

    2015-09-15

    Zinc phosphate glasses (PZABPTb) in the compositional system: P{sub 2}O{sub 5}–ZnO–Al{sub 2}O{sub 3}–BaO–PbO doped with variable Tb{sup 3+} concentrations (1–5 wt% Tb{sub 2}O{sub 3}) were prepared and characterized through absorption, excitation, emission and intensity decay rate measurements. The Judd–Ofelt model has been adopted to evaluate the radiative properties of the {sup 5}D{sub 4}→{sup 7}F{sub 6–3} emission transitions. The effect of Tb{sup 3+} ion concentration on the emissions from the {sup 5}D{sub 3,4} excited levels is discussed in detail. Analysis of the intensity decay curves corresponding to blue and green emissions from levels {sup 5}D{sub 3} and {sup 5}D{sub 4}, respectively, allowed determination of effective lifetimes, which confirmed the Tb{sup 3+} ion concentration quenching of the blue emission in these glasses. The decay curves for the {sup 5}D{sub 3} level are found to be non-exponential in nature for all the studied concentrations due to ion–ion energy transfer through cross-relaxation. In an attempt to identify the origin of the energy transfer mechanism, the decay curves were well fitted to the Inokuti–Hirayama model for S=6, which indicates that the energy transfer process is of dipole–dipole type. The optical band gap energy (E{sub opt}) has been evaluated taking into account the ultraviolet edge of absorption spectra. - Highlights: • Tb{sup 3+}-doped zinc phosphate glasses have been prepared by melt quenching technique. • Spectroscopic parameters were evaluated using the Judd–Ofelt theory. • Effects of Tb{sup 3+} concentration on luminescence of the glasses were studied. • Strong intense laser transition for Tb{sup 3+} ion in PZABPTb glasses is {sup 5}D{sub 4}→{sup 7}F{sub 5} (0.54 μm). • PZABPTb glasses could be used in the development of green color display devices and solid state visible lasers.

  4. The Changes of P-fractions and Solubility of Phosphate Rock in Ultisol Treated by Organic Matter and Phosphate Rock

    Directory of Open Access Journals (Sweden)

    Heru Bagus Pulunggono

    2012-09-01

    Full Text Available Phosphorus (P is one of the essential elements for plant, however, its availability is mostly very low in acid soils. It is well documented that application of phosphate rock and organic matter are able to change the level of availability of P-form in acid soils. The objective of the research were to evaluate the changes of P-fractions ( resin-P, NaHCO3-Pi, and NaHCO3-Po and phosphate rock dissolution which were induced by application of organic matter (Imperata cylindrica, Pueraria javanica, dan Colopogonium mucunoides and phosphate rock in Utisol Lampung. The experiment was designed in a completely randomized design with three factors and three replications. The first factor was the types of organic matter (I. cylindrica, P. javanica, and C. mucunoides, the second factor was the rate of organic matter (0, 2.5, and 5%, and the third factor was the rate of phosphate rock (0, 40, and 80 mg P kg-1. The results showed that in the rate of 0 and 1% organic matter, the type of organic matter did not affect P-fraction of NaHCO3-Pi, but in the rate of 2.5 and 5%, NaHCO3-Pi due to application of P. javanica, and C. mucunoides higher than due to application of I. cylindrica. However, the increasing rate of organic matter increased NaHCO3-Pi. Then, P-fraction of Resin-Pi was affected by the type of organic matter, the rate of organic matter, and the rate of phosphate rock, respectively. P-fraction of resin-Pi due to application of P. javanica, and C. mucunoides was higher than due to application of I. cylindrica, but the effect of P. javanica, and C. mucunoides was not different. Increasing the rate of organic matter and phosphate rock increased P-fraction of resin-Pi and NaHCO3-Pi, but P-fraction of NaHCO3-Po was not affected by all treatments. Meanwhile, dissolution of phosphate rock was affected by the kind of organic matter and soil reaction. In the rate of 5% organic matter, dissolution of phosphate rock by application of I. cylindrica (70% was higher

  5. Heat accumulation regime of femtosecond laser writing in fused silica and Nd:phosphate glass

    Energy Technology Data Exchange (ETDEWEB)

    Bukharin, M.A. [Moscow Institute of Physics and Technology, Moscow Region (Russian Federation); Optosystems Ltd., Troitsk, Moscow (Russian Federation); Khudyakov, D.V. [Optosystems Ltd., Troitsk, Moscow (Russian Federation); Physics Instrumentation Center of the General Physics Institute, Troitsk, Moscow (Russian Federation); Vartapetov, S.K. [Physics Instrumentation Center of the General Physics Institute, Troitsk, Moscow (Russian Federation)

    2015-04-01

    We investigated refractive index induced by direct femtosecond laser writing inside fused silica and Nd:phosphate glass in heat accumulation regime. Spatial profile and magnitude of induced refractive index were investigated at various pulse repetition rates and translation velocities. It was shown that the magnitude of induced refractive index significantly rises with decreasing in time interval between successive laser pulses below the time for thermal diffusion. Going from nonthermal regime to heat accumulation regime, we achieved induced refractive index growth from 4 x 10{sup -3} up to 6.5 x 10{sup -3} in fused silica and from -6 x 10{sup -3} to -9 x 10{sup -3} in Nd:phosphate glass. Aspect ratio of treated area decreased from 2.1 down to less than 1.5 without correcting optical elements. It was shown that in heat accumulation regime, the treated area was surrounded by region of alternatively changed refractive index with significant magnitude up to -2 x 10{sup -3}. Wide regions of decreased refractive index enable fabrication of depressed cladding waveguides. We demonstrated low-loss (0.3 dB/cm) tubular waveguide inside fused silica. For orthogonal polarizations of guiding light, we achieved a small difference between losses as 0.1 dB/cm using highly symmetric written tracks forming the cladding. The desired structure was simulated with the beam propagation method, and the results were in good agreement with experiment data. (orig.)

  6. Concentration dependent spectroscopic properties of Dy{sup 3+} ions doped boro-phosphate glasses

    Energy Technology Data Exchange (ETDEWEB)

    Mariyappan, M.; Marimuthu, K., E-mail: mari-ram2000@yahoo.com [Department of Physics, Gandhigram Rural Institute - Deemed University, Gandhigram – 624 302 (India)

    2016-05-23

    Dy{sup 3+} ions doped boro-phosphate glasses have been synthesized by melt quenching method and characterized through FTIR, absorption and luminescence spectral measurements. The presence of various stretching and bending vibrations of different borate and phosphate groups were identified from the FTIR spectra. In order to examine the electronic band structure of the studied glasses, Optical energy gap (E{sub opt}) and Urbach energy (ΔE) values were estimated from the absorption spectra. The Judd-Ofelt (JO) intensity parameters were calculated to examine the symmetry of the ligand environment around the Dy{sup 3+} ions site. The emission spectra exhibit two intense emission bands at around 482 nm (blue) and 574 nm (yellow) corresponding to the {sup 4}F{sub 9/2}→{sup 6}H{sub 15/2} and {sup 4}F{sub 9/2}→{sup 6}H{sub 13/2} transitions respectively. The emission spectra were characterized through Commission International d’Eclairage (CIE) 1931 chromaticity diagram to explore its suitability for WLED applications.

  7. Magnesium Coated Bioresorbable Phosphate Glass Fibres: Investigation of the Interface between Fibre and Polyester Matrices

    Directory of Open Access Journals (Sweden)

    Xiaoling Liu

    2013-01-01

    Full Text Available Bioresorbable phosphate glass fibre reinforced polyester composites have been investigated as replacement for some traditional metallic orthopaedic implants, such as bone fracture fixation plates. However, composites tested revealed loss of the interfacial integrity after immersion within aqueous media which resulted in rapid loss of mechanical properties. Physical modification of fibres to change fibre surface morphology has been shown to be an effective method to improve fibre and matrix adhesion in composites. In this study, biodegradable magnesium which would gradually degrade to Mg2+ in the human body was deposited via magnetron sputtering onto bioresorbable phosphate glass fibres to obtain roughened fibre surfaces. Fibre surface morphology after coating was observed using scanning electron microscope (SEM. The roughness profile and crystalline texture of the coatings were determined via atomic force microscope (AFM and X-ray diffraction (XRD analysis, respectively. The roughness of the coatings was seen to increase from 40±1 nm to 80±1 nm. The mechanical properties (tensile strength and modulus of fibre with coatings decreased with increased magnesium coating thickness.

  8. Influence of phosphate glass recrystallization on the stability of a waste matrix to leaching

    Science.gov (United States)

    Yudintsev, S. V.; Pervukhina, A. M.; Mokhov, A. V.; Malkovsky, V. I.; Stefanovsky, S. V.

    2017-04-01

    In Russia, highly radioactive liquid wastes from recycling of spent fuel of nuclear reactors are solidified into Na-Al-P glass for underground storage. The properties of the matrix including the radionuclide fixation will change with time due to crystallization. This is supported by the results of study of the interaction between glassy matrices, products of their crystallization, and water. The concentration of Cs in a solution at the contact of a recrystallized sample increased by three orders of magnitude in comparison with an experiment with glass. This difference is nearly one order of magnitude for Sr, Ce, and Nd (simulators of actinides) and U due to their incorporation into phases with low solubility in water. Based on data on the compositional change of solutions after passing through filters of various diameters, it is concluded that Cs occurs in the dissolved state in runs with a glass and recrystallized matrix. At the same time, Sr, lanthanides, and U occur in the dissolved state and in the composition of colloids in runs with glass, and mostly in colloid particles after contact with the recrystallized sample. These results should be regarded for substantiation of safety for geological waste storage.

  9. Solubility of actinides and surrogates in nuclear glasses; Solubilite des actinides et de leurs simulants dans les verres nucleaires. Limites d'incorporation et comprehension des mecanismes

    Energy Technology Data Exchange (ETDEWEB)

    Lopez, Ch

    2003-07-01

    The nuclear wastes are currently incorporated in borosilicate glass matrices. The resulting glass must be perfectly homogeneous. The work discussed here is a study of actinide (thorium and plutonium) solubility in borosilicate glass, undertaken to assess the extent of actinide solubility in the glass and to understand the mechanisms controlling actinide solubilization. Glass specimens containing; actinide surrogates were used to prepare and optimize the fabrication of radioactive glass samples. These preliminary studies revealed that actinide Surrogates solubility in the glass was enhanced by controlling the processing temperature, the dissolution kinetic of the surrogate precursors, the glass composition and the oxidizing versus reducing conditions. The actinide solubility was investigated in the borosilicate glass. The evolution of thorium solubility in borosilicate glass was determined for temperatures ranging from 1200 deg C to 1400 deg C.Borosilicate glass specimens containing plutonium were fabricated. The experimental result showed that the plutonium solubility limit ranged from 1 to 2.5 wt% PuO{sub 2} at 1200 deg C. A structural approach based on the determination of the local structure around actinides and their surrogates by EXAFS spectroscopy was used to determine their structural role in the glass and the nature of their bonding with the vitreous network. This approach revealed a correlation between the length of these bonds and the solubility of the actinides and their surrogates. (author)

  10. Structural and luminescence studies on Dy{sup 3+} doped lead boro–telluro-phosphate glasses

    Energy Technology Data Exchange (ETDEWEB)

    Selvi, S. [Department of Physics, Gandhigram Rural University, Gandhigram 624302 (India); Venkataiah, G. [Department of Physics, Sri Venkateswara University, Tirupati 517502 (India); Arunkumar, S.; Muralidharan, G. [Department of Physics, Gandhigram Rural University, Gandhigram 624302 (India); Marimuthu, K., E-mail: mari_ram2000@yahoo.com [Department of Physics, Gandhigram Rural University, Gandhigram 624302 (India)

    2014-12-01

    This paper reports results obtained on the structural and luminescence properties of Dy{sup 3+}doped lead boro−telluro-phosphate glasses prepared following the melt quenching technique. FTIR spectra exhibit the presence of B−O vibrations, P−O−P symmetric vibrations and Te−O stretching modes of TeO{sub 3} and TeO{sub 6} units. The metal–ligand bond was identified through UV−vis−NIR absorption spectra and to determine the band tailing parameter, direct and indirect band gap energy of the prepared glasses. The Judd−Ofelt (JO) intensity parameters (Ω{sub 2}, Ω{sub 4} and Ω{sub 6}), experimental and theoretical oscillator strengths were also determined and reported. Luminescence measurements were made to determine the transition probability (A), stimulated emission cross-section (σ{sub P}{sup E}) and branching ratio (β{sub R}) for the transitions that include {sup 4}F{sub 9/2}→{sup 6}H{sub 11/2}, {sup 6}H{sub 13/2} and {sup 6}H{sub 15/2} bands. The effect of Dy{sup 3+} ion concentration on the intensity ratio of yellow to blue emission bands has also been studied and reported. The lifetime corresponding to the {sup 4}F{sub 9/2} level of the title glasses has been found to decrease with the increase in Dy{sup 3+} ion concentration. The chromaticity coordinates (x,y) have been estimated from the luminescence spectra and the suitability of title glasses for white light applications has been analyzed using CIE chromaticity diagram. The variation of optical properties with the concentration of dysprosium oxide content in the glasses have been studied and reported.

  11. Structural and luminescence studies on Dy3+ doped lead boro-telluro-phosphate glasses

    Science.gov (United States)

    Selvi, S.; Venkataiah, G.; Arunkumar, S.; Muralidharan, G.; Marimuthu, K.

    2014-12-01

    This paper reports results obtained on the structural and luminescence properties of Dy3+doped lead boro-telluro-phosphate glasses prepared following the melt quenching technique. FTIR spectra exhibit the presence of B-O vibrations, P-O-P symmetric vibrations and Te-O stretching modes of TeO3 and TeO6 units. The metal-ligand bond was identified through UV-vis-NIR absorption spectra and to determine the band tailing parameter, direct and indirect band gap energy of the prepared glasses. The Judd-Ofelt (JO) intensity parameters (Ω2, Ω4 and Ω6), experimental and theoretical oscillator strengths were also determined and reported. Luminescence measurements were made to determine the transition probability (A), stimulated emission cross-section (σPE) and branching ratio (βR) for the transitions that include 4F9/2→6H11/2, 6H13/2 and 6H15/2 bands. The effect of Dy3+ ion concentration on the intensity ratio of yellow to blue emission bands has also been studied and reported. The lifetime corresponding to the 4F9/2 level of the title glasses has been found to decrease with the increase in Dy3+ ion concentration. The chromaticity coordinates (x,y) have been estimated from the luminescence spectra and the suitability of title glasses for white light applications has been analyzed using CIE chromaticity diagram. The variation of optical properties with the concentration of dysprosium oxide content in the glasses have been studied and reported.

  12. Red light generation through the lead boro-telluro-phosphate glasses activated by Eu3+ ions

    Science.gov (United States)

    Selvi, S.; Marimuthu, K.; Suriya Murthy, N.; Muralidharan, G.

    2016-09-01

    Lead boro-telluro-phosphate glasses containing 0.05 to 2.0 wt% of Eu3+ ions were prepared through melt quenching technique. Structural characteristics of title glasses were identified through XRD, FTIR and Raman studies. The optical properties of the prepared glasses were studied using UV-Vis-NIR absorption and photoluminescence spectra. From the resultant spectra, we have obtained the bonding parameters (δ), nephelauxetic ratio (β), direct and indirect band gaps and Urbach energy (ΔE) values. A deep red luminescence due to 5D0 → 7F2 transition of Eu3+ ions could be observed for the title glasses. The local site symmetry around the Eu3+ ions and the degree of Eu3+-O2- covalence were assessed from the luminescence intensity ratio of 5D0 → 7F2/5D0 → 7F1 transitions. Judd-Ofelt intensity parameters, calculated from the luminescence spectra, were used to estimate the radiative parameters like transition probability (A), branching ratio (βexp, βcal) and stimulated emission cross-section (σPE) concerning the 5D0 → 7FJ (J = 0, 1, 2, 3 and 4) transitions. The important laser parameters, gain bandwidth and optical gain are also estimated. The decay curves associated with the transition from 5D0 state was found to be single-exponential at all Eu3+ ion concentrations. CIE colour coordinates and colour purity of the prepared glasses were estimated from the CIE chromaticity diagram.

  13. Role of metal ion solubility in leaching of nuclear waste glasses

    International Nuclear Information System (INIS)

    Grambow, B.

    1982-04-01

    From the results of a variety of experiments it can be concluded that reaction of the matrix is the fundamental process that occurs in the leaching of PNL 76-68 glass. This reaction has two aspects. Without solubility restrictions, congruent leaching behavior occurs at all pH values and leachant compositions. When this reaction raises solution concentrations of certain elements to the level at which new solid phases form, these phases will regulate the solution concentration. These solid phases are dominant constituents of the leached layer. For the leaching of PNL 76-68 glass, the solubilities of these reaction products regulate the solution concentration as if the solution is in equilibrium with pure Fe(OH) 3 (amorphous), Zn(OH) 2 (amorphous), Nd(OH) 3 , SrCO 3 or CaCO 3 . The experimental conditions, in particular the pH value, that govern the formation of solid reaction products and control of the solution concentrations can be identified

  14. Biosolubilization of poorly soluble rock phosphates by Aspergillus tubingensis and Aspergillus niger

    Energy Technology Data Exchange (ETDEWEB)

    Reddy, M.S.; Kumar, S.; Babita, K. [Thapar Institute of Engineering and Technology, Patiala (India). School of Biotechnology; Reddy, M.S. [Auburn University, AL (United States). Department of Entomology and Plant Pathology

    2002-09-01

    Three isolates of Aspergillus tubingensis and two isolates of Aspergillus niger isolated from rhizospheric soils were tested on solubilization of different rock phosphates. All the isolates of Aspergillus were capable of solubilizing all the natural rock phosphates. A. tubingensis (AT1) showed maximum percent solubilization in all the rock phosphates tested in this study when compared to other isolates. This isolate also showed highest phosphorus (P) solubilization when grown in the presence of 2% of rock phosphate. A. tubingensis (AT1) seems to be more efficient in solubilization of rock phosphates compared to other isolates reported elsewhere. This is the first report of rock phosphate solubilization by A. tubingensis and might provide an efficient large scale biosolubilization of rock phosphates intended for P fertilizer. (author)

  15. Spectroscopic properties of Ho{sup 3+}-doped K-Sr-Al phosphate glasses

    Energy Technology Data Exchange (ETDEWEB)

    Linganna, K.; Rathaiah, M.; Venkatramu, V. [Yogi Vemana University, Department of Physics, Kadapa (India); Jayasankar, C.K. [Sri Venkateswara University, Department of Physics, Tirupati (India)

    2014-05-15

    Trivalent holmium-doped K-Sr-Al phosphate glasses (P{sub 2}O{sub 5}-K{sub 2}O-SrO-Al{sub 2}O{sub 3}-Ho{sub 2}O{sub 3}) were prepared, and their spectroscopic properties have been evaluated using absorption, emission, and excitation measurements. The Judd-Ofelt theory has been used to derive spectral intensities of various absorption bands from measured absorption spectrum of 1.0 mol% Ho{sub 2}O{sub 3}-doped K-Sr-Al phosphate glass. The Judd-Ofelt intensity parameters (Ω{sub λ}, x 10{sup -20} cm{sup 2}) have been determined of the order of Ω{sub 2} = 11.39, Ω{sub 4} = 3.59, and Ω{sub 6} = 2.92, which in turn used to derive radiative properties such as radiative transition probability, radiative lifetime, branching ratios, etc. for excited states of Ho{sup 3+} ions. The radiative lifetimes for the {sup 5}F{sub 4}, {sup 5}S{sub 2}, and {sup 5}F{sub 5} levels of Ho{sup 3+} ions are found to be 169, 296, and 317 μs, respectively. The stimulated emission cross-section for 2.05-μm emission was calculated by the McCumber theory and found to be 9.3 x 10{sup -21} cm{sup 2}. The wavelength-dependent gain coefficient with population inversion rate has been evaluated. The results obtained in the titled glasses are discussed systematically and compared with other Ho{sup 3+}-doped systems to assess the possibility for visible and infrared device applications. (orig.)

  16. Influence of silver and copper doping on luminescent properties of zinc-phosphate glasses after x-ray irradiation

    Science.gov (United States)

    Murashov, Alexander A.; Sidorov, Alexander I.; Shakhverdov, Teimur A.; Stolyarchuk, Maxim V.

    2017-11-01

    It is shown, experimentally, that in silver- and copper-containing zinc-phosphate glasses, metal molecular clusters are formed during the glass synthesis. X-ray irradiation of these glasses led to the considerable increase of its luminescence in visible spectral range. This effect is caused by the transformation of the charged metal molecular clusters into the neutral state. Luminescence and excitation spectra of the glass, doped with silver and copper simultaneously, change significantly in comparison with the spectra of glasses doped with one metal. The reason for this can be the formation of hybrid AgnCum molecular clusters. The computer simulation of the structure and optical properties of such clusters by the time-dependent density functional theory method is presented. It is shown that the optimal luminescent material for photonics application, in comparison with other studied materials, is glass, containing hybrid molecular clusters.

  17. Kinetics of copper nanoparticle precipitation in phosphate glass: an isothermal plasmonic approach.

    Science.gov (United States)

    Sendova, Mariana; Jiménez, José A; Smith, Robert; Rudawski, Nicholas

    2015-01-14

    The kinetics of copper nanoparticle (NP) precipitation in melt-quenched barium-phosphate glass has been studied by in situ isothermal optical micro-spectroscopy. A spectroscopically based approximation technique is proposed to obtain information about the activation energies of nucleation and growth in a narrow temperature range (530-570 °C). Pre-plasmonic and plasmonic NP precipitation stages are identified separated in time. The process as a whole is discussed employing classical nucleation/growth theory and the Kolmogorov-Johnson-Mehl-Avrami phase change model. Activation energies of 3.9(7) eV and 2.6(5) eV have been estimated for the pre-plasmonic and plasmonic spectroscopically assessed stages, respectively. High resolution transmission electron microscopy, differential scanning calorimetry, and Raman spectroscopy were used as complementary techniques for studying the nanoparticulate phase and glass host structure. An empirical linear dependence of the diffusion activation energy on the glass transition temperature with broad applicability is suggested.

  18. Investigations on optical properties of Sm3+ ion doped boro-phosphate glasses

    Science.gov (United States)

    Vijayakumar, R.; Suthanthirakumar, P.; Karthikeyan, P.; Marimuthu, K.

    2015-06-01

    The Sm3+ doped Boro-phosphate glasses with the chemical composition 60H3BO3+20Li2CO3+10ZnO+(10-x) H6NO4P+xSm2O3 (where x= 0.1, 0.5, 1 and 2 in wt%) have been prepared by melt quenching technique. The prepared glasses were characterized through optical absorption and luminescence spectral measurements. The band gap energies corresponding to the direct and indirect allowed transitions and the Urbach's energy values were estimated from the absorption spectra. Judd-Ofelt intensity parameters have been derived to predict the radiative properties of the various emission transitions. In order to identify the emission color of the prepared glasses, the emission intensities were analyzed using CIE 1931 color chromaticity diagram. The energy transfer process takes place between Sm3+-Sm3+ ions through cross-relaxation mechanism have also been investigated and the results were discussed and reported.

  19. Investigations on optical properties of Sm{sup 3+} ion doped boro-phosphate glasses

    Energy Technology Data Exchange (ETDEWEB)

    Vijayakumar, R.; Suthanthirakumar, P.; Karthikeyan, P.; Marimuthu, K., E-mail: mari-ram2000@yahoo.com [Department of Physics, Gandhigram Rural Institute – Deemed University, Gandhigram – 624302 (India)

    2015-06-24

    The Sm{sup 3+} doped Boro-phosphate glasses with the chemical composition 60H{sub 3}BO{sub 3}+20Li{sub 2}CO{sub 3}+10ZnO+(10−x) H{sub 6}NO{sub 4}P+xSm{sub 2}O{sub 3} (where x= 0.1, 0.5, 1 and 2 in wt%) have been prepared by melt quenching technique. The prepared glasses were characterized through optical absorption and luminescence spectral measurements. The band gap energies corresponding to the direct and indirect allowed transitions and the Urbach’s energy values were estimated from the absorption spectra. Judd-Ofelt intensity parameters have been derived to predict the radiative properties of the various emission transitions. In order to identify the emission color of the prepared glasses, the emission intensities were analyzed using CIE 1931 color chromaticity diagram. The energy transfer process takes place between Sm{sup 3+}−Sm{sup 3+} ions through cross-relaxation mechanism have also been investigated and the results were discussed and reported.

  20. Development and evaluation of holmium doped phosphate glass microspheres for selective internal radiotherapy

    International Nuclear Information System (INIS)

    Barros Filho, Eraldo C.; Martinelli, Jose Roberto; Squair, Peterson L; Osso Junior, Joao A.; Sene, Frank Ferrer

    2013-01-01

    Selective Internal Radiotherapy is used to treat hepatocellular carcinoma. In this treatment 90 Y -doped aluminosilicate glass microspheres are introduced in the hepatic artery and they migrate to the liver near to the tumor where they are trapped in the arterioles. The radiation β- emitted by the decay of 90 Y annihilates the cancer cells. A macroaggregate of albumin containing technetium is previously used to monitor the lung shunt and to prevent the spreading of 90 Y during the treatment. In the present work, 165 Ho- doped phosphate glass microspheres were developed aiming that application. 165 Ho has high cross section for neutron capture (64 bars) and 166 Ho decays emitting β- radiation with appropriate energy for killing cancer cells, and gamma rays with low energy which can be used to obtain images of the microspheres location and to check possible occurrence of lung shunt. Holmium also is highly paramagnetic and can be used to obtain images whereby NMR. The glass matrix consists of (P 2 O 5 ) tetrahedrons and can be produced by a relatively lower melting temperature of chemical compounds. The 31 P decays by emitting β- radiation and contributes to the absorbed dose, helping to annihilate the cancer cells. The microspheres were produced by using two methods: the flame and the gravitation falling methods to obtain microspheres with appropriate properties. (author)

  1. Quantum efficiency and excited-state relaxation dynamics in neodymium-doped phosphate laser glasses

    International Nuclear Information System (INIS)

    Caird, J.A.; Ramponi, A.J.; Staver, P.R.

    1991-01-01

    Radiometrically calibrated spectroscopic techniques employing an integrating-sphere detection system have been used to determine the fluorescence quantum efficiencies for two commercially available Nd 3+ -doped phosphate laser glasses, LG-750 and LG-760. Quantum efficiencies and fluorescence lifetimes were measured for samples with various neodymium concentrations. It is shown that the effects of concentration quenching are accurately described when both resonant nonradiative excitation hopping (the Burshtein model) and annihilation by cross relaxation are accounted for by Foerster--Dexter dipole--dipole energy-transfer theory. The Foerster--Dexter critical range for nonradiative excitation hopping was found to be R DD =11 A, while the critical range for cross relaxation was close to R DA =4 A in these glasses. The quantum efficiency at low Nd 3+ concentrations was (92±5)%, implying a nonradiative relaxation rate of 210±150 s -1 for isolated ions. Improved values for the radiative lifetimes and the stimulated emission cross sections for these glasses were also deduced from the measurements

  2. Gamma rays shielding and sensing application of some rare earth doped lead-alumino-phosphate glasses

    Science.gov (United States)

    Kaur, Preet; Singh, Devinder; Singh, Tejbir

    2018-03-01

    Seven rare earth (Sm3+, Eu3+ and Nd3+) doped lead alumino phosphate glasses were prepared. The protective and sensing measures from gamma rays were analysed in terms of parameters viz. density (ρ), refractive index, energy band gap (Eg), mean free path (mfp), effective atomic number (Zeff) and buildup factors (energy absorption EABF as well as exposure buildup factor EBF). The energy dependent parameters (mfp, Zeff, EABF and EBF) were investigated in the energy region from 15 keV to 15 MeV. EABF and EBF values were observed to be maximum in the intermediate energy region. Besides, the EABF and EBF values for the prepared samples are shown to have strong dependence on chemical composition of the glass at lower energy, whereas, it is almost independent of chemical composition in higher energy region. The prepared glass samples are found to have potential applications in radiation shielding as well as radiation sensing, which further find numerous applications in the field of medicine and industry.

  3. Application of Cu{sub 2}O-doped phosphate glasses for bandpass filter

    Energy Technology Data Exchange (ETDEWEB)

    Elhaes, H. [Physics Department, Faculty of Women for Arts, Science and Education, Ain Shams University, 11757 Cairo (Egypt); Attallah, M., E-mail: m_atallah94@yahoo.com [Basic Science Department, Higher Technological Institute, 10th of Ramadan City (Egypt); Elbashar, Y.; El-Okr, M. [Physics Department, Faculty of Science, Al Azhar University, Cairo (Egypt); Ibrahim, M. [Spectroscopy Department, National Research Centre, 12311 Dokki, Cairo (Egypt)

    2014-09-15

    Phosphate glasses doped with copper ions having general composition 42P{sub 2}O{sub 5}–39ZnO–(18−x) Na{sub 2}O–1CaO–xCu{sub 2}O [x=2, 4, 6, 8, 10 mol%] were prepared using a conventional melt-quench technique. Physical and chemical properties of the glasses were investigated using X-ray diffraction technique and UV–visible optical absorption. The density was measured by Archimedes' method, and molar volume (V{sub M}) was calculated. It is found that density and molar volume show opposite trend by increasing Cu{sub 2}O content. Absorbance and transmittance at the normal incidence are measured by a spectrophotometer in the spectral range of 190–1100 nm. Analyses of the obtained results were considered in the frame of current theories. Absorption data were used for absorption coefficient, the optical band gap (E{sub opt}), the cutoff in UV and IR bands to the bandpass filter, which confirmed the optical properties of this type of filter. E{sub opt} values for different glass samples are found to decrease with increasing Cu{sub 2}O content.

  4. Silver aggregates and twofold-coordinated tin centers in phosphate glass: A photoluminescence study

    International Nuclear Information System (INIS)

    Jimenez, J.A.; Lysenko, S.; Liu, H.; Fachini, E.; Resto, O.; Cabrera, C.R.

    2009-01-01

    The optical properties of silver species in various oxidation and aggregation states and of tin centers in melt-quenched phosphate glasses have been assessed by optical absorption and photoluminescence (PL) spectroscopy. Glasses containing silver and tin, or either dopant, were studied. Emission and excitation spectra along with time-resolved and temperature-dependent PL measurements were employed in elucidating the different emitting centers observed and investigating on their interactions. In regard to silver, the data suggests the presence of luminescent single Ag + ions, Ag + -Ag + and Ag + -Ag 0 pairs, and nonluminescent Ag nanoparticles (NPs), where Ag + -Ag 0 →Ag + -Ag + energy transfer is indicated. Tin optical centers appear as twofold-coordinated Sn centers displaying PL around 400 nm ascribed to triplet-to-singlet electronic transitions. The optically active silver centers were observed in glasses where 8 mol% of both Ag 2 O and SnO, and 4 mol% of Ag 2 O were added. Heat treatment (HT) of the glass with the high concentration of silver and tin leads to chemical reduction of ionic silver species resulting in a large volume fraction of silver NPs and the vanishing of silver PL features. Further characterization of such heat-treated glass by transmission electron microscopy and X-ray photoelectron spectroscopy appears consistent with silver being present mainly in nonoxidized form after HT. On the other hand, HT of the glass containing only silver results in the quenching of Ag + -Ag 0 pairs emission that is ascribed to nonradiative energy transfer to Ag NPs due to the positioning of the pairs near the surface of NPs during HT. In this context, an important finding is that a faster relaxation was observed for this nanocomposite in relation to a heat-treated glass containing both silver and tin (no silver pairs) as revealed by degenerate four-wave mixing spectroscopy. Such result is attributed to Ag NP→Ag + -Ag 0 plasmon resonance energy transfer. The

  5. Solubility and dissolution kinetics study of uranium phosphates and vanadates: implications for the front end of the electronuclear cycle

    International Nuclear Information System (INIS)

    Cretaz, F.

    2013-01-01

    In the current context of restart of the nuclear energy, the needs in uranium are expected to increase significantly. Moreover, in a perspective of sustainable development, the exploitation, the treatment and the purification of uranium ores need to be optimized. It is thus necessary to determine reliable thermodynamic data (and especially solubility constants) for the systems of interest, especially uranium(VI) phosphates and vanadates. In this aim, a multi parametric study of the dissolution of meta-torbernite Cu 0.8 (H 3 O) 0.2 (UO 2 ) 2 (PO 4 ) 2.8 H 2 O, meta-autunite Ca(UO 2 ) 2 (PO 4 ) 2.6 H 2 O, meta-ankoleite K 2 (UO 2 ) 2 (PO 4 ) 2.6 H 2 O and carnotite K 2 (UO 2 ) 2 (VO 4 ) 2.3 H 2 O was undertaken. First, analogues of these four minerals were synthesized, based only on dry chemistry process for carnotite or on wet chemistry methods for the phosphate phases. They were then extensively characterized (in terms of structure, microstructure and chemical composition). It particularly highlighted the similar structures of such compounds. The anionic groups (PO 4 3- or V 2 O 8 6- ) and uranyl form parallel layers between which counter cations (Cu 2+ , Ca 2+ or K + ) and water molecules are inserted. However, the counter cations present in the interlayer space of the three phosphate phases present different lability. The synthetic phases were also compared to their natural analogues, except for meta-ankoleite, which allowed us to point out significant differences in the composition (presence of impurities in natural samples) and the morphology (grain size). The dissolution of these phases was then studied from a kinetic and thermodynamic point of view, through leaching tests in static and dynamic conditions, in various acid media (sulfuric, nitric and hydrochloric) and at different temperatures. In these conditions, the dissolution of meta-autunite was found to be un-congruent due to the precipitation of uranyl phosphate then avoiding the determination of

  6. Investigating the effect of silver coating on the solubility, antibacterial properties, and cytocompatibility of glass microspheres.

    Science.gov (United States)

    Haas, L M; Smith, C M; Placek, L M; Hall, M M; Gong, Y; Mellott, N P; Wren, Anthony W

    2015-10-01

    Silver (Ag) coatings have been incorporated into many medical materials due to its ability to eradicate harmful microbes. In this study, glass microspheres (SiO2-Na2O-CaO-Al2O3) were synthesized and employed as substrates to investigate the effect Ag coating has on glass solubility and the subsequent biological effects. Initially, glasses were amorphous with a glass transition point (T(g)) of 605℃ and microspheres were spherical with a mean particle diameter of 120 µm (±27). The Ag coating was determined to be crystalline in nature and its presence was confirmed using scanning electron microscopy and X-ray photoelectron spectroscopy. Ion release determined that Ag-coated (Ag-S) microspheres increased the Na(+) release rate but slightly reduced the Ca(2+) and Si(4+) release compared to an uncoated control (UC-S). Additionally, the Ag-S reduced the pH to just above neutral (7.3-8.5) compared to the UC-S (7.7-9.1). Antibacterial testing determined significant reductions in planktonic Escherichia coli (p = 0.000), Staphylococcus epidermidis (p = 0.000) and Staphylococcus aureus (p = 0.000) growth as a function of the presence of Ag and with respect to maturation (1, 7, and 30 days). Testing for toxicity levels using L929 Fibroblasts determined higher cell viability for the Ag-S at lower concentrations (5 µg/ml); in addition, no significant reduction in cell viability was observed with higher concentrations (15, 30 µg/ml). © The Author(s) 2015.

  7. Effect of nanosecond UV laser irradiation on luminescence and absorption in silver- and copper-containing phosphate glasses

    Science.gov (United States)

    Murashov, A. A.; Sidorov, A. I.; Stoliarchuk, M. V.

    2018-03-01

    Experimental evidence is presented that nanosecond UV laser irradiation of silver- and copper-containing barium phosphate glasses leads to luminescence quenching in the visible range. Subsequent heat treatment induces an absorption in the range 350–500 nm. These effects are due to the ionisation and fragmentation of subnanometre molecular clusters by laser radiation and subsequent (heat treatment-induced) formation of nanoparticles possessing plasmon resonance. Our numerical modelling results demonstrate the feasibility of producing stable AgnCum hybrid molecular clusters in glass. Local modification of the optical properties of glass by laser light can be used for optical information recording.

  8. Study of the surface crystallization and resistance to dissolution of niobium phosphate glasses for nuclear waste immobilization

    International Nuclear Information System (INIS)

    Vieira, Heveline

    2008-01-01

    The surface crystallization and the dissolution rate of three phosphate glass compositions containing different amounts of niobium oxide were studied. The glasses were named Nb30, Nb37, and Nb44 according to the nominal content of niobium oxide in the glass composition. The three compositions were evaluated keeping the P 2 O 5 /K 2 O ratio constant and varying the amount of Nb 2 O 5 . These glasses were produced by melting appropriate chemical compounds at 1500 deg C for 0.5 hour. The crystalline phases which were nucleated on the glass surface after heat treatment were determined by X-ray diffraction. The crystalline structures depend on the amount of niobium oxide in the glass composition. The crystal morphologies were observed by using an optical microscope, and their characteristics are specific for each kind of crystalline phase. The crystal growth rate and the surface nuclei density were determined for each glass composition, and they depend on each crystalline phase nucleated on the surface. From the differential thermal analysis curves it was determined that the Nb44 glass containing 46.5 mol por cent of niobium oxide is the most thermally stable against crystallization when compared to the Nb30 and Nb37 glasses. According to the activation energies determined for crystal growth on the surface of each glass type, the Nb44 glass can also be considered the most resistant one against crystallization. The dissolution rate for the Nb44 glass after 14 days immersed in an aqueous solution with pH equals to 7 at 90 deg C is the lowest (9.0 x 10 -7 g. cm -2 . day -1 ) when compared to the other two glass compositions. The dissolution rates in acidic and neutral solutions of all studied glasses meet the international standards for materials which can be used in the immobilization of nuclear wastes. (author)

  9. Er3+ phosphate glass optical waveguide amplifiers at 1.5 μm on silicon

    Science.gov (United States)

    Yan, Yingchao; Faber, Anne J.; de Waal, Henk

    1996-01-01

    RF-sputtering techniques were employed to produce Er-doped phosphate glass films on thermally oxidized silicon wafers. Film compositions were characterized by X-ray photoelectron spectroscopy. As-deposited films showed very low Er luminescence lifetimes. By postannealing of deposited films in pure oxygen, Er photoluminescence emission lifetime of the 4I13/2 - 4I15/2 transition could be increased from 1 - 2 ms to 8 - 9 ms. The long Er lifetime of the deposited films is very promising for achieving an optical gain. A dependence of measured lifetimes on pump power was observed which are related to a up-conversion quenching process. After postannealing, the sputtered waveguides showed relatively low attenuation loss at the potential pumping and signaling wavelengths. The loss spectrum from 700 nm to 1600 nm was measured by two-prism coupling. The films were easy to be patterned by lithography and ridge channel waveguides were developed by argon plasma etching.

  10. Single-step fabrication of stressed waveguides with tubular depressed-cladding in phosphate glasses using ultrafast vortex laser beams

    Directory of Open Access Journals (Sweden)

    Cheng Guanghua

    2013-11-01

    Full Text Available We report on the fabrication of the stressed optical waveguide with tubular depressed-refractive-index cladding in phosphate glasses by use of femtosecond vortex beam. Strained regions were emerged in domains surrounding the tubular track. Waveguiding occurs mainly within the tube induced by femtosecond laser.

  11. Sulphate solubility and sulphate diffusion in oxide glasses: implications for the containment of sulphate-bearing nuclear wastes

    International Nuclear Information System (INIS)

    Lenoir, M.

    2009-09-01

    The thesis deals with sulphate solubility and sulphate diffusion in oxide glasses, in order to control sulphate incorporation and sulphate volatilization in nuclear waste glasses. It was conducted on simplified compositions, in the SiO 2 -B 2 O 3 -R 2 O (R = Li, Na, K, Cs), SiO 2 -B 2 O 3 -BaO and V 2 O 5 -B 2 O 3 -BaO systems. These compositions allowed us to study the influence of the nature of network-modifying ions (Li + , Na + , K + , Cs + or Ba 2+ ) and also of former elements (Si, B, V), on structure and properties of glasses. Sulphate volatility is studied in sodium borosilicate melts using an innovative technique of sulphate quantitation with Raman spectroscopy. This technique is useful to obtain kinetic curves of sulphate volatilization. The establishment of a model to fit these curves leads to the determination of diffusion coefficients of sulphate. These diffusion coefficients can thus be compared to diffusion coefficients of other species, determined by other techniques and presented in the literature. They are also linked to diffusion coefficients in relation with the viscosity of the melts. Concerning sulphate solubility in glasses, it depends on glass composition and on the nature of sulphate incorporated. Sulphate incorporation in alkali borosilicate glasses leads to the formation of a sulphate layer floating on top of the melt. Sulphate incorporation in barium borosilicate and boro-vanadate glasses leads to the crystallization of sulphate species inside the vitreous matrix. Moreover, sulphate solubility is higher in these glasses than in alkali borosilicates. Finally, exchanges between cations present in glasses and cations present in the sulphate phase are also studied. (author)

  12. Investigating the use of coupling agents to improve the interfacial properties between a resorbable phosphate glass and polylactic acid matrix.

    Science.gov (United States)

    Hasan, Muhammad Sami; Ahmed, Ifty; Parsons, Andrew J; Rudd, Chris D; Walker, Gavin S; Scotchford, Colin A

    2013-09-01

    Eight different chemicals were investigated as potential candidate coupling agents for phosphate glass fibre reinforced polylactic acid composites. Evidence of reaction of the coupling agents with phosphate glass and their effect on surface wettability and glass degradation were studied along with their principle role of improving the interface between glass reinforcement and polymer matrix. It was found that, with an optimal amount of coupling agent on the surface of the glass/polymer, interfacial shear strength improved by a factor of 5. Evidence of covalent bonding between agent and glass was found for three of the coupling agents investigated, namely: 3-aminopropyltriethoxysilane; etidronic acid and hexamethylene diisocyanate. These three coupling agents also improved the interfacial shear strength and increased the hydrophobicity of the glass surface. It is expected that this would provide an improvement in the macroscopic properties of full-scale composites fabricated from the same materials which may also help to retain these properties for the desired length of time by retarding the breakdown of the fibre/matrix interface within these composites.

  13. Thermal properties and surface reactivity in simulated body fluid of new strontium ion-containing phosphate glasses.

    Science.gov (United States)

    Massera, J; Petit, L; Cardinal, T; Videau, J J; Hupa, M; Hupa, L

    2013-06-01

    In this paper, we investigate the effect of SrO substitution for CaO in 50P₂O₅-10Na₂-(40-x)CaO-xSrO glass system (x from 0 to 40) on the thermal and structural properties and also on the glass reactivity in simulated body fluid (SBF) in order to find new glass candidates for biomedical glass fibers. The addition of SrO at the expense of CaO seems to restrain the leaching of phosphate ions in the solution limiting the reduction of the solution pH. We observed the formation of an apatite layer at the surface of the glasses when in contact with SBF. SrO and MgO were found in the apatite layer of the strontium ion-containing glasses, the concentration of which increases with an increase of SrO content. We think that it is the presence of MgO and SrO in the layer which limits the leaching of phosphate in the solution and thus the glass dissolution in SBF.

  14. Characterization of aqueous interactions of copper-doped phosphate-based glasses by vapour sorption.

    Science.gov (United States)

    Stähli, Christoph; Shah Mohammadi, Maziar; Waters, Kristian E; Nazhat, Showan N

    2014-07-01

    Owing to their adjustable dissolution properties, phosphate-based glasses (PGs) are promising materials for the controlled release of bioinorganics, such as copper ions. This study describes a vapour sorption method that allowed for the investigation of the kinetics and mechanisms of aqueous interactions of PGs of the formulation 50P2O5-30CaO-(20-x)Na2O-xCuO (x=0, 1, 5 and 10mol.%). Initial characterization was performed using (31)P magic angle spinning nuclear magnetic resonance and attenuated total reflectance-Fourier transform infrared spectroscopy. Increasing CuO content resulted in chemical shifts of the predominant Q(2) NMR peak and of the (POP)as and (PO(-)) Fourier transform infrared absorptions, owing to the higher strength of the POCu bond compared to PONa. Vapour sorption and desorption were gravimetrically measured in PG powders exposed to variable relative humidity (RH). Sorption was negligible below 70% RH and increased exponentially with RH from 70 to 90%, where it exhibited a negative correlation with CuO content. Vapour sorption in 0% and 1% CuO glasses resulted in phosphate chain hydration and hydrolysis, as evidenced by protonated Q(0)(1H) and Q(1)(1H) species. Dissolution rates in deionized water showed a linear correlation (R(2)>0.99) with vapour sorption. Furthermore, cation release rates could be predicted based on dissolution rates and PG composition. The release of orthophosphate and short polyphosphate species corroborates the action of hydrolysis and was correlated with pH changes. In conclusion, the agreement between vapour sorption and routine characterization techniques in water demonstrates the potential of this method for the study of PG aqueous reactions. Copyright © 2014 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

  15. Development of large scale production of Nd-doped phosphate glasses for megajoule-scale laser systems

    International Nuclear Information System (INIS)

    Ficini, G.; Campbell, J.H.

    1996-01-01

    Nd-doped phosphate glasses are the preferred gain medium for high-peak-power lasers used for Inertial Confinement Fusion research because they have excellent energy storage and extraction characteristics. In addition, these glasses can be manufactured defect-free in large sizes and at relatively low cost. To meet the requirements of the future mega-joule size lasers, advanced laser glass manufacturing methods are being developed that would enable laser glass to be continuously produced at the rate of several thousand large (790 x 440 x 44 mm 3 ) plates of glass per year. This represents more than a 10 to 100-fold improvement in the scale of the present manufacturing technology

  16. Titanium phosphate glass microcarriers induce enhanced osteogenic cell proliferation and human mesenchymal stem cell protein expression

    Directory of Open Access Journals (Sweden)

    Nilay J Lakhkar

    2015-11-01

    Full Text Available In this study, we have developed 50- to 100-µm-sized titanium phosphate glass microcarriers (denoted as Ti5 that show enhanced proliferation of human mesenchymal stem cells and MG63 osteosarcoma cells, as well as enhanced human mesenchymal stem cell expression of bone differentiation markers, in comparison with commercially available glass microspheres at all time points. We also demonstrate that these microcarriers provide superior human mesenchymal stem cell proliferation with conventional Dulbecco’s Modified Eagle medium than with a specially developed commercial stem cell medium. The microcarrier proliferative capacity is revealed by a 24-fold increase in MG63 cell numbers in spinner flask bioreactor studies performed over a 7-day period, versus only a 6-fold increase in control microspheres under the same conditions; the corresponding values of Ti5 and control microspheres under static culture are 8-fold and 7-fold, respectively. The capability of guided osteogenic differentiation is confirmed by ELISAs for bone morphogenetic protein-2 and osteopontin, which reveal significantly greater expression of these markers, especially osteopontin, by human mesenchymal stem cells on the Ti5 microspheres than on the control. Scanning electron microscopy and confocal laser scanning microscopy images reveal favorable MG63 and human mesenchymal stem cell adhesion on the Ti5 microsphere surfaces. Thus, the results demonstrate the suitability of the developed microspheres for use as microcarriers in bone tissue engineering applications.

  17. In Situ Wire Drawing of Phosphate Glass in Polymer Matrices for Material Extrusion 3D Printing

    Directory of Open Access Journals (Sweden)

    J. Gilberto Siqueiros

    2017-01-01

    Full Text Available A strategy to increase the amount of materials available for additive manufacturing platforms such as material extrusion 3D printing (ME3DP is the creation of printable thermoplastic composites. Potential limiters to the incorporation of filler materials into a thermoplastic resin include agglomeration of the filler materials, which can compromise the mechanical properties of the material system and a static morphology of the filler material. A potential solution to these issues is the use of filler materials with low glass transition temperatures allowing for a change in morphology during the extrusion process. Here, we successfully demonstrate the drawing of phosphate glass particles into a wire-like morphology within two polymeric systems: (1 a rubberized acrylonitrile butadiene styrene (ABS blend and (2 polylactic acid (PLA. After applying a normalization process to account for the effect of air gap within the 3D printed test specimens, an enhancement in the mechanical properties was demonstrated where an increase in strength was as high as 21% over baseline specimens. Scanning electron microanalysis was used to characterize the fracture surface and wire drawing efficacy. Factors affecting the ability to achieve wire drawing such as polymer viscosity and print temperature are also highlighted.

  18. Photoluminescence properties of Er{sup 3+}-doped alkaline earth titanium phosphate glasses

    Energy Technology Data Exchange (ETDEWEB)

    Murthy, D.V.R.; Babu, A. Mohan [Department of Physics, Sri Venkateswara University, Tirupati 517 502 (India); Jamalaiah, B.C. [Department of Physics, Sree Vidyanikethan Engineering College, Tirupati, 517 102 (India); Moorthy, L. Rama, E-mail: lrmphysics@yahoo.co.i [Department of Physics, Sri Venkateswara University, Tirupati 517 502 (India); Jayasimhadri, M.; Jang, Kiwan; Lee, Ho Sueb [Department of Physics, Changwon National University, Changwon 641-773 (Korea, Republic of); Yi, Soung Soo [Department of Photonics, Silla University, Pusan 617-736 (Korea, Republic of); Jeong, Jung Hyun [Department of Physics, Pukyong National University, Pusan 608-737 (Korea, Republic of)

    2010-02-18

    Er{sup 3+}-doped alkaline earth titanium phosphate (RTP) glasses with molar composition of 24 (NaPO{sub 3}){sub 6} + 30 KH{sub 2}PO{sub 4} + 25 TiO{sub 2} + 20 RCl{sub 2} + 1 Er{sub 2}O{sub 3} were prepared by melt quenching technique. Judd-Ofelt intensity parameters ({Omega}{sub 2,4,6}) were determined from the experimental oscillator strengths (f{sub exp}) of absorption bands. From these parameters spontaneous emission probabilities (A{sub R}), luminescence branching ratios ({beta}{sub R}) and radiative lifetimes ({tau}{sub R}) have been calculated. Visible and near infrared photoluminescence spectra has been recorded by exciting the samples at 380 and 970 nm respectively. An intense broad emission band at 1.53 {mu}m was observed corresponding to {sup 4}I{sub 13/2} {yields} {sup 4}I{sub 15/2} transition. McCumber theory has been applied to determine the emission cross-sections ({sigma}{sub e}) of the {sup 4}I{sub 13/2} {yields} {sup 4}I{sub 15/2} transition using the absorption cross-sections ({sigma}{sub a}). The lifetimes of {sup 4}S{sub 3/2} level were measured for the glasses by exciting the samples at 540 nm wavelength and the quantum efficiencies were also determined.

  19. Structural characterizations and optical properties of new Li–Sr–Nb-phosphate glasses

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Yi-Mu [Department of Electronic Engineering, National United University, Miao-Li 36003, Taiwan, ROC (China); Hsu, S.M. [Department of Biomedical Imaging and Radiological Sciences, National Yang-Ming University, Taipei 11221, Taiwan, ROC (China); Yung, S.W., E-mail: hwyang@nuu.edu.tw [Department of Material Science and Engineering, National United University, Miao-Li 36003, Taiwan, ROC (China); Zhang, T. [Institute for Materials Research, Fuzhou University, Fujian (China); Huang, Y.S.; Wu, J.J. [Department of Material Science and Engineering, National United University, Miao-Li 36003, Taiwan, ROC (China); Hsu, C.H. [Department of Electrical Engineering, National United University, Miao-Li 36003, Taiwan, ROC (China); Chin, T.S. [Department of Materials Science and Engineering, Feng Chia University, Taichung, Taiwan, ROC (China)

    2014-04-01

    A new Li{sub 2}O–SrO–Nb{sub 2}O{sub 5}–P{sub 2}O{sub 5} glass system was prepared by a high-temperature alumina crucible, and structural characterization and optical properties were investigated. Proper content of Li{sub 2}O and Nb{sub 2}O{sub 5} was employed to replace partial SrO and P{sub 2}O{sub 5} to improve the optical properties. It was observed that the enhancement of the refractive index from 1.75 to 1.85 is mainly due to the Nb{sub 2}O{sub 5} content. An addition of Li{sub 2}O significantly increases the optical transmittance; optical transparency can be enhanced from 60% to higher than 85% in the UV–visible region with addition of 20–40 mol% Li{sub 2}O species. However, optical transmittance is monotonically decreased from about 90% to 80% under 10–30 mol% Nb{sub 2}O{sub 5} addition. The 40P{sub 2}O{sub 5}–20Nb{sub 2}O{sub 5}–20SrO–20Li{sub 2}O glasses demonstrate the optimum refractive index (n > 1.75) and high optical transparency (>80%) in the UV–visible region. Furthermore, the effect of Nb{sub 2}O{sub 5} on the structural transition was focused on the (60 − y)P{sub 2}O{sub 5}–yNb{sub 2}O{sub 5}–20SrO–20Li{sub 2}O vitreous system since the transition of FTIR spectra reveals that the Nb{sub 2}O{sub 5} has more pronounced effect than Li{sub 2}O in the glass network due to the higher covalent extent and electronegativity. Addition of Nb{sub 2}O{sub 5} generates Nb–O bonds by dissociating P–O chains and results in the decrease in the intensity of the (PO{sub 2}), (POP), and (PO{sub 3}) absorption bands. The O1s-XPS analysis shows that Nb{sub 2}O{sub 5} addition dissociates symmetric bridging oxygens in P–O–P bonding and forms asymmetric bridging oxygens in P–O–Nb and non-bridging Nb–O{sup -} bonds, in which octahedral [NbO{sub 6}] unit is eventually substituted by [NbO{sub 4}] tetrahedral unit in the Li–Sr–Nb phosphate glasses. - Highlights: • The prepared glasses demonstrate great optical properties

  20. POTENTIAL EFFECTS OF PHOSPHATE PRODUCTS ON LEAD SOLUBILITY IN PLUMBING SYSTEMS

    Science.gov (United States)

    Lead concentrations in drinking water can be minimized by adjusting the pH and alkalinity. Such lead solubility controls, however, may be offset by other water treatment measures that inadvertently increase lead solubility, e.g., the adding of polyphosphate-containing products. ...

  1. Synthesis, characterization and bioactivity of a calcium-phosphate glass-ceramics obtained by the sol-gel processing method

    Energy Technology Data Exchange (ETDEWEB)

    Jmal, Nouha, E-mail: jmalnouha@gmail.com; Bouaziz, Jamel

    2017-02-01

    In this work, a calcium-phosphate glass-ceramics was successfully obtained by heat treatment of a mixture of 26.52 in wt.% of fluorapatite (Fap) and 73.48 in wt.% of 77S (77 SiO{sub 2}−14 CaO−9 P{sub 2}O{sub 5} in wt.%) gel. The calcium phosphate-glass-ceramics was prepared by sol-gel process with tetraethyl orthosilicate (TEOS), triethyl phosphate (TEP), calcium nitrate and fluorapatite. The synthesized powders were characterized by some commonly used tools such as X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), {sup 31}P magic angle spinning nuclear magnetic resonance (MAS-NMR), scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), and thin-film X-ray diffraction (TF-XRD). The obtained results seemed to confirm the nucleation and growth of hydroxyapatite (Hap) nano-phase in the glass. Moreover, an in-vitro evaluation of the glass-ceramic was performed. In addition, to assess its bioactive capacity, it was soaked in simulated body fluid (SBF) at different time intervals. The SEM, EDS and TF-XRD analyses showed the deposition of hydroxyapatite on the surface of the specimens after three days of immersion in SBF solution. The mechanical properties of the obtained material such as rupture strength, Vickers hardness and elastic modulus were measured. In addition, the friction coefficient of calcium phosphate-glass-ceramics was tested. The values of the composite of rupture strength (24 MPa), Vickers hardness (214 Hv), Young's modulus (52.3 GPa), shear modulus (19 GPa) and friction coefficient (0.327) were obtained. This glass-ceramics can have useful applications in dental prostheses. Indeed, this material may have promising applications for implants because of its content of fluorine, the effective protector against dental caries. - Highlights: • A novel three phases Fap-Hap-glass-ceramics is prepared by sol–gel route. • Results showed a nucleation and growth of hydroxyapatite nano-phase in the glass.

  2. Synthesis, characterization and bioactivity of a calcium-phosphate glass-ceramics obtained by the sol-gel processing method

    International Nuclear Information System (INIS)

    Jmal, Nouha; Bouaziz, Jamel

    2017-01-01

    In this work, a calcium-phosphate glass-ceramics was successfully obtained by heat treatment of a mixture of 26.52 in wt.% of fluorapatite (Fap) and 73.48 in wt.% of 77S (77 SiO 2 −14 CaO−9 P 2 O 5 in wt.%) gel. The calcium phosphate-glass-ceramics was prepared by sol-gel process with tetraethyl orthosilicate (TEOS), triethyl phosphate (TEP), calcium nitrate and fluorapatite. The synthesized powders were characterized by some commonly used tools such as X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), 31 P magic angle spinning nuclear magnetic resonance (MAS-NMR), scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), and thin-film X-ray diffraction (TF-XRD). The obtained results seemed to confirm the nucleation and growth of hydroxyapatite (Hap) nano-phase in the glass. Moreover, an in-vitro evaluation of the glass-ceramic was performed. In addition, to assess its bioactive capacity, it was soaked in simulated body fluid (SBF) at different time intervals. The SEM, EDS and TF-XRD analyses showed the deposition of hydroxyapatite on the surface of the specimens after three days of immersion in SBF solution. The mechanical properties of the obtained material such as rupture strength, Vickers hardness and elastic modulus were measured. In addition, the friction coefficient of calcium phosphate-glass-ceramics was tested. The values of the composite of rupture strength (24 MPa), Vickers hardness (214 Hv), Young's modulus (52.3 GPa), shear modulus (19 GPa) and friction coefficient (0.327) were obtained. This glass-ceramics can have useful applications in dental prostheses. Indeed, this material may have promising applications for implants because of its content of fluorine, the effective protector against dental caries. - Highlights: • A novel three phases Fap-Hap-glass-ceramics is prepared by sol–gel route. • Results showed a nucleation and growth of hydroxyapatite nano-phase in the glass. • Fap-Hap-glass

  3. Development of continuous glass melting for production of Nd-doped phosphate glasses for the NIF and LMJ laser system

    International Nuclear Information System (INIS)

    Campbell, J. H.; Ficini-Dorn, G.; Hawley-Fedder, R.; McLean, M. J.; Suratwala, T.; Trombert, J. H.

    1998-01-01

    The NIF and LMJ laser systems require about 3380 and 4752 Nd-doped laser glass slabs, respectively. Continuous laser glass melting and forming will be used for the first time to manufacture these slabs. Two vendors have been chosen to produce the glass: Hoya Corporation and Schott Glass Technologies. The laser glass melting systems that each of these two vendors have designed, built and tested are arguably the most advanced in the world. Production of the laser glass will begin on a pilot scale in the fall of 1999

  4. Comparative investigation on the spectroscopic properties of Pr³⁺-doped boro-phosphate, boro-germo-silicate and tellurite glasses.

    Science.gov (United States)

    Zhang, Liaolin; Dong, Guoping; Peng, Mingying; Qiu, Jianrong

    2012-07-01

    We report on the spectroscopic properties of Pr(3+)-doped boro-phosphate, boro-germo-silicate and tellurite glasses. The stimulated absorption and emission cross sections were estimated. Only one emission at 596 nm and 605 nm is observed in Pr(3+)-doped boro-phosphate and boro-germo-silicate glasses, respectively, while three emissions at 605 nm, 612 nm and 645 nm are observed in Pr(3+)-doped tellurite glass when excited at 467 nm. The fluorescence lifetime at 600 nm in Pr(3+)-doped boro-phosphate, boro-germo-silicate and tellurite glasses is 137 μs, 73 μs and 51 μs, respectively. The emissions from Pr(3+)-doped boro-phosphate, boro-germo-silicate and tellurite glasses show different decay behaviors and can be well explained by multiphonon relaxation theory. Copyright © 2012 Elsevier B.V. All rights reserved.

  5. Phosphate fertilizers with varying water-solubility applied to Amazonian soils: II. Soil P extraction methods

    International Nuclear Information System (INIS)

    Muraoka, T.; Brasil, E.C.; Scivittaro, W.B.

    2002-01-01

    A pot experiment was carried out under greenhouse conditions at the Centro de Energia Nuclear na Agricultura, Piracicaba (SP, Brazil), to evaluate the phosphorus availability of different phosphate sources in five Amazonian soils. The soils utilized were: medium texture Yellow Latosol, clayey Yellow Latosol, very clayey Yellow Latosol, clayey Red-Yellow Podzolic and very clayey Red-Yellow Podzolic. Four phosphate sources were applied: triple superphosphate, ordinary Yoorin thermophosphate, coarse Yoorin termo-phosphate and North Carolina phosphate rock at P rates of 0, 40, 80 and 120 mg kg -1 soil. The dry matter yield and the amount of P taken up by cowpea and rice were correlated with the extractable P by anionic exchangeable resin, Mehlich-1, Mehlich-3 and Bray-I. The results showed that the extractable P by Mehlich-1 was higher in the soils amended with North Carolina rock phosphate. Irrespective of the phosphorus sources used, the Mehlich-3 extractant showed close correlation with plant response. The Mehlich-3 and Bray-I extractants were more sensitive to soil variations. The Mehlich-3 extractant was more suitable in predicting the P availability to plants in the different soils and phosphorus sources studied. (author)

  6. Short- and long-term effects of sparingly soluble phosphates on crop ...

    African Journals Online (AJOL)

    availability and cultivated to various food and economic crops. The rock phosphates (particularly SRP) were more efficient than SSP in soil A but had less than 50% relative agronomic efficiency (RAE) in soil B, especially when tomato was the test crop.

  7. Electronic polarizability, optical basicity and interaction parameter for Nd2O3 doped lithium-zinc-phosphate glasses

    Science.gov (United States)

    Algradee, M. A.; Sultan, M.; Samir, O. M.; Alwany, A. Elwhab B.

    2017-08-01

    The Nd3+-doped lithium-zinc-phosphate glasses were prepared by means of conventional melt quenching method. X-ray diffraction results confirmed the glassy nature of the studied glasses. The physical parameters such as the density, molar volume, ion concentration, polaron radius, inter-ionic distance, field strength and oxygen packing density were calculated using different formulae. The transmittance and reflectance spectra of glasses were recorded in the wavelength range 190-1200 nm. The values of optical band gap and Urbach energy were determined based on Mott-Davis model. The refractive indices for the studied glasses were evaluated from optical band gap values using different methods. The average electronic polarizability of the oxide ions, optical basicity and an interaction parameter were investigated from the calculated values of the refractive index and the optical band gap for the studied glasses. The variations in the different physical and optical properties of glasses with Nd2O3 content were discussed in terms of different parameters such as non-bridging oxygen and different concentrations of Nd cation in glass system.

  8. Characterization of iron phosphate glasses prepared by microwave heating; Obtencao de vidros fosfatos contendo ferro por meio do aquecimento em fornos de microondas

    Energy Technology Data Exchange (ETDEWEB)

    Almeida, Fabio Jesus Moreira de

    2006-07-01

    Phosphate glasses have been investigated since the fifties, because they are relatively easy to prepare, have low melting temperatures (1000 deg C - 1200 deg C), and low glass transition. However, these glasses were very sensitive to humidity, showing a very low chemical durability. Iron phosphate glasses have been prepared by melting inorganic precursors in conventional electric furnaces and induction furnaces. By adding iron, phosphate glasses became chemical resistant and were thought to be used as nuclear waste forms or mechanical resistance fibers. The use of microwaves has been investigated because it makes possible a fast and homogeneous heating of the materials. Microwave promotes the self-heating of the material by the interaction of the external electromagnetic field with the molecules and ions of the material. Niobium phosphate glasses was also produced already through the heating of precursors in microwave ovens. Other glasses containing iron in theirs structure was produced by conventional furnaces and they had your structures analyzed. But even so, it was not still published synthesis of iron phosphate glasses starting from the melting of precursors materials in microwave ovens. In the present work mixtures of (NH{sub 4}){sub 2}HPO{sub 4} and Fe{sub 3}O{sub 4} or (NH{sub 4}){sub 2}HPO{sub 4} and Fe{sub 2}O{sub 3} were exposed to microwave energy with electromagnetic waves of 2,45 GHz. It was proposed that the absorption of this radiation for the material causes the heating from room temperature to melting temperature. The obtained iron phosphate glasses was analyzed by X-ray diffraction, Moessbauer spectroscopy, and Differential Thermal Analysis. Iron phosphate glasses were also produced in electrical furnaces for comparison. (author)

  9. Effects of CuO co-doping on γ-ray irradiation resistance of active ions doped phosphate glasses

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Zhihuan [Key Laboratory for Ultrafine Materials of Ministry of Education, School of Materials Science and Engineering, East China University of Science and Technology, Shanghai 200237 (China); ENEA-UTTMAT, Via Anguillarese 301, 00123 Rome (Italy); Baccaro, Stefania; Cemmi, Alessia [ENEA-UTTMAT, Via Anguillarese 301, 00123 Rome (Italy); Shen, Wei [Key Laboratory for Ultrafine Materials of Ministry of Education, School of Materials Science and Engineering, East China University of Science and Technology, Shanghai 200237 (China); Chen, Guorong, E-mail: grchen@ecust.edu.cn [Key Laboratory for Ultrafine Materials of Ministry of Education, School of Materials Science and Engineering, East China University of Science and Technology, Shanghai 200237 (China)

    2013-09-15

    The effect of copper ion doping on the γ-ray irradiation resistance of Mn{sup 2+} and Pr{sup 3+} doped phosphate glasses has been studied. UV–visible transmission spectra and photoluminescence spectra have been measured before and after γ-irradiation to characterize the radiation-induced defects. The electron paramagnetic resonance spectra of the irradiated samples with, and without Cu ions have been compared to show the ability of Cu ions to suppress the generation of radiation-induced color centers. The differential transmission spectra and the radiation-induced absorption coefficients have also been calculated for discussion of the observed phenomena. The much improved γ-irradiation resistance of Mn{sup 2+} and Pr{sup 3+} doped phosphate glasses has been demonstrated through CuO co-doping.

  10. Chemically durable iron phosphate glasses for vitrifying sodium bearing waste (SBW) using conventional and cold crucible induction melting (CCIM) techniques

    Energy Technology Data Exchange (ETDEWEB)

    Kim, C.W. E-mail: cheol@umr.edu; Ray, C.S.; Zhu, D.; Day, D.E.; Gombert, D.; Aloy, A.; Mogus-Milankovic, A.; Karabulut, M

    2003-11-01

    A simulated sodium bearing waste (SBW) was successfully vitrified in iron phosphate glasses (IPG) at a maximum waste loading of 40 wt% using conventional and cold crucible induction melting (CCIM) techniques. No sulfate segregation or crystalline phases were detectable in the IPG when examined by SEM and XRD. The IPG wasteforms containing 40 wt% SBW satisfy current DOE requirements for aqueous chemical durability as evaluated from their bulk dissolution rate (D{sub R}), product consistency test, and vapor hydration test. The fluid IPG wasteforms can be melted at a relatively low temperature (1000 deg. C) and for short times (<6 h). These properties combined with a significantly higher waste loading, and the feasibility of CCIM melting offer considerable savings in time, energy, and cost for vitrifying the SBW stored at the Idaho National Engineering and Environmental Laboratory in iron phosphate glasses.

  11. Fluorescent nuclear track images of Ag-activated phosphate glass irradiated with photons and heavy charged particles

    Energy Technology Data Exchange (ETDEWEB)

    Kurobori, Toshio, E-mail: kurobori@staff.kanazawa-u.ac.jp [Graduate School of Natural Science and Technology, Kanazawa University, Kakuma, Kanazawa 920-1192 (Japan); Yanagida, Yuka [Oarai Research Center, Chiyoda Technol Corporation, Oarai-machi, Ibaraki 311-1313 (Japan); Kodaira, Satoshi [National Institute of Radiological Sciences, 4-9-1 Anagawa, Inage-ku, Chiba 263-8555 (Japan); Shirao, Taichi [Nikon Instech Co., Ltd., Tanakanishi, Sakyo-ku, Kyoto 606-8221 (Japan)

    2017-05-21

    In this paper we report about the demonstration of the nuclear track imaging capabilities of Ag-activated phosphate glass. A 375 nm laser and confocal laser scanning microscopy (CLSM) were respectively used for track excitation and detection. Specifically, the blue and orange radiophotoluminescent (RPL) tracks and dose distributions observed after irradiation with soft X-rays, gamma rays and heavy charged particles (HCPs) are examined. In addition, the origins of the reductions in RPL efficiency for high-dose X-ray irradiation and for irradiation with HCPs with high linear energy transfer (LET) values are investigated via a CLSM and a conventional fluorescent reader and discussed. - Highlights: • 3D track images are demonstrated using a confocal laser microscopy. • Fluorescent track detectors are based on RPL Ag-doped phosphate glass. • The dose distributions are examined for X-ray, gamma ray and HCP irradiations. • The origins of the reduction in RPL efficiency are investigated and discussed.

  12. Fluorescent nuclear track images of Ag-activated phosphate glass irradiated with photons and heavy charged particles

    International Nuclear Information System (INIS)

    Kurobori, Toshio; Yanagida, Yuka; Kodaira, Satoshi; Shirao, Taichi

    2017-01-01

    In this paper we report about the demonstration of the nuclear track imaging capabilities of Ag-activated phosphate glass. A 375 nm laser and confocal laser scanning microscopy (CLSM) were respectively used for track excitation and detection. Specifically, the blue and orange radiophotoluminescent (RPL) tracks and dose distributions observed after irradiation with soft X-rays, gamma rays and heavy charged particles (HCPs) are examined. In addition, the origins of the reductions in RPL efficiency for high-dose X-ray irradiation and for irradiation with HCPs with high linear energy transfer (LET) values are investigated via a CLSM and a conventional fluorescent reader and discussed. - Highlights: • 3D track images are demonstrated using a confocal laser microscopy. • Fluorescent track detectors are based on RPL Ag-doped phosphate glass. • The dose distributions are examined for X-ray, gamma ray and HCP irradiations. • The origins of the reduction in RPL efficiency are investigated and discussed.

  13. Bioresorbable screws reinforced with phosphate glass fibre: manufacturing and mechanical property characterisation.

    Science.gov (United States)

    Felfel, R M; Ahmed, I; Parsons, A J; Rudd, C D

    2013-01-01

    Use of bioresorbable screws could eliminate disadvantages associated with metals such as removal operations, corrosion, MRI interference and stress shielding. Mechanical properties of bioresorbable polymers alone are insufficient for load bearing applications application as screws. Thus, reinforcement is necessary to try and match or surpass the mechanical properties of cortical bone. Phosphate based glass fibres were used to reinforce polylactic acid (PLA) in order to produce unidirectionally aligned (UD) and unidirectionally plus randomly distributed (UD/RM) composite screws (P40 UD and P40 UD/RM). The maximum flexural and push-out properties for the composite screws (P40 UD and P40 UD/RM) increased by almost 100% in comparison with the PLA screws. While the pull-out strength and stiffness of the headless composite screws were ∼80% (strength) and ∼130% (stiffness) higher than for PLA, those with heads exhibited properties lower than those for PLA alone as a result of failure at the heads. An increase in the maximum shear load and stiffness for the composite screws (∼30% and ∼40%) in comparison to the PLA screws was also seen. Maximum torque for the PLA screws was ∼1000 mN m, while that for the composite screws were slightly lower. The SEM micrographs for P40 UD and P40 UD/RM screws revealed small gaps around the fibres, which were suggested to be due to buckling of the UD fibres during the manufacturing process. Copyright © 2012 Elsevier Ltd. All rights reserved.

  14. Effect of radiative trapping on measurement of the spectroscopic properties of Yb sup 3 sup + :phosphate glasses

    CERN Document Server

    Dai Shi Xun; Wen Lei; Hu Li Li; Jiang Zhong Hon

    2003-01-01

    The effect of radiative trapping on measurement of the spectroscopic properties of Yb sup 3 sup + -doped phosphate glasses was investigated as a function of Yb sup 3 sup + concentration at different thicknesses. It was found that radiative trapping exists generally in Yb sup 3 sup + :phosphate glasses, even at low concentration. As a result, the measured lifetime of Yb sup 3 sup + in phosphate glasses is usually larger than the calculated one. The maximum discrepancies between them at high concentration are found to be <42%. The calculated lifetime should be used as a reference in determining the true value of the measured lifetime because of it being lengthened largely by radiative trapping. On the other hand, the shape of fluorescence spectrum exhibits remarkable changes due to the radiative trapping. What is more, the intensity increase of DELTA lambda sub e sub f sub f at high concentration is greater than that of low doping. The DELTA lambda sub e sub f sub f increases 36% from 53 to 72 nm with thickn...

  15. Nonlinear optical characterization of phosphate glasses based on ZnO using the Z-scan technique

    International Nuclear Information System (INIS)

    Mojdehi Masoumeh Shokati; Yunus Wan Mahmood Mat; Talib Zainal Abidin; Tamchek, N.; Fhan Khor Shing

    2013-01-01

    The nonlinear optical properties of a phosphate vitreous system [(ZnO) x − (MgO) 30−x − (P 2 O 5 ) 70 ], where x = 8, 10, 15, 18, and 20 mol% synthesized through the melt-quenching technique have been investigated by using the Z-scan technique. In the experiment, a continuous-wave laser with a wavelength of 405 nm was utilized to determine the sign and value of the nonlinear refractive (NLR) index and the absorption coefficient with closed and opened apertures of the Z-scan setup. The NLR index was found to increase with the ZnO concentration in the glass samples by an order of 10 −10 cm 2 ·W −1 . The real and imaginary parts of the third-order nonlinear susceptibility were calculated by referring to the NLR index (n 2 ) and absorption coefficient (β) of the samples. The value of the third-order nonlinear susceptibility was presented by nonlinear refractive or absorptive behavior of phosphate glasses for proper utilization in nonlinear optical devices. Based on the measurement, the positive sign of the NLR index shows a self-focusing phenomenon. The figures of merit for each sample were calculated to judge the potential of phosphate glasses for application in optical switching

  16. Physical and optical properties of calcium sulfate ultra-phosphate glass-doped Er2O3

    Science.gov (United States)

    Aliyu, Aliyu Mohammed; Hussin, R.; Deraman, Karim; Ahmad, N. E.; Danmadami, Amina M.; Yamusa, Y. A.

    2018-03-01

    The influence of erbium on physical and optical properties of calcium sulfate ultra-phosphate glass was investigated using conventional melt quench process. Selected samples of composition 20CaSO4 (80 - x) P2O5- xEr2O3 with 0.1 ≤x ≤ 0.9 mol.% were prepared and assessed. X-ray diffraction (XRD) techniques were used to confirm the amorphous nature of the said samples. The structural units of phosphate-based glass were assessed from Raman spectra as ultra-(Q3), meta-(Q2), pyro-(Q1) and orthophosphate (Q0) units. Depolymerization process of the glasses was testified for higher calcium oxide content and UV-visible for optical measurement. Thermal analysis have been investigated by means of thermogravimetric analysis. The results show the decomposition of materials in the temperature range of 25∘C-1000∘C. Er3+ absorption spectra were measured in the range of 400-1800nm. PL measurement was carried out in order to obtain the excitation and emission spectra of the samples. The emission spectra excited at 779nm comprises of 518nm, 550nm and 649nm of transition 4F9/2, 4S3/2 and 2H11/2 excited states to 4I15/2 ground state. In physical properties, the density calculated using Archimedes method is inversely proportional to molar volume with increase in Er3+ ions. Optical bandgap (Eg) were determined using Tauc’s plots for direct transitions where Eg (direct) decreases with increase in erbium content. The refractive index increases with decreasing molar volume; this may have a tendency for larger optical bandgap. The result obtained from the glass matrix indicates that erbium oxide-doped calcium sulfate ultra-phosphate may give important information for wider development of functional glasses.

  17. Role of SrO on the bioactivity behavior of some ternary borate glasses and their glass ceramic derivatives

    Science.gov (United States)

    Abdelghany, A. M.; Ouis, M. A.; Azooz, M. A.; ElBatal, H. A.; El-Bassyouni, G. T.

    2016-01-01

    Borate glasses containing SrO substituting both CaO and NaO were prepared and characterized for their bioactivity or bone bonding ability. Glass ceramic derivatives were prepared by thermal heat treatment process. FTIR, XRD and SEM measurements for the prepared glass and glass-ceramics before and after immersion in sodium phosphate solution for one and two weeks were carried out. The appearance of two IR peaks within the range 550-680 cm-1 after immersion in phosphate solution indicates the formation of hydroxyapatite or equivalent Sr phosphate layer. X-ray diffraction data agree with the FTIR spectral analysis. The solubility test was carried out for both glasses and glass ceramics derivatives in the same phosphate solution. The introduction of SrO increases the solubility for both glasses and glass ceramics and this is assumed to be due to the formation of Sr phosphate which is more soluble than calcium phosphate (hydroxyapatite). SEM images reveal varying changes in the surfaces of glass ceramics after immersion according to the SrO content.

  18. Role of SrO on the bioactivity behavior of some ternary borate glasses and their glass ceramic derivatives.

    Science.gov (United States)

    Abdelghany, A M; Ouis, M A; Azooz, M A; ElBatal, H A; El-Bassyouni, G T

    2016-01-05

    Borate glasses containing SrO substituting both CaO and NaO were prepared and characterized for their bioactivity or bone bonding ability. Glass ceramic derivatives were prepared by thermal heat treatment process. FTIR, XRD and SEM measurements for the prepared glass and glass-ceramics before and after immersion in sodium phosphate solution for one and two weeks were carried out. The appearance of two IR peaks within the range 550-680cm(-1) after immersion in phosphate solution indicates the formation of hydroxyapatite or equivalent Sr phosphate layer. X-ray diffraction data agree with the FTIR spectral analysis. The solubility test was carried out for both glasses and glass ceramics derivatives in the same phosphate solution. The introduction of SrO increases the solubility for both glasses and glass ceramics and this is assumed to be due to the formation of Sr phosphate which is more soluble than calcium phosphate (hydroxyapatite). SEM images reveal varying changes in the surfaces of glass ceramics after immersion according to the SrO content. Copyright © 2015 Elsevier B.V. All rights reserved.

  19. Structural and luminescence properties of Sm3+ -doped bismuth phosphate glass for orange-red photonic applications.

    Science.gov (United States)

    Damodaraiah, S; Reddy Prasad, V; Ratnakaram, Y C

    2018-05-01

    In the present study, the effect of bismuth oxide (Bi 2 O 3 ) content on the structural and optical properties of 0.5Sm 3+ -doped phosphate glass and the effect of concentration on structural and optical properties of Sm 3+ -doped bismuth phosphate (BiP) glass were studied. Structural characterization was accomplished using X-ray diffraction (XRD), scanning electron microscopy (SEM) with energy dispersive spectroscopy (EDS), Fourier transform infrared (FTIR) spectroscopy and 31 P nuclear magnetic resonance (NMR) spectroscopy. Optical properties were studied using absorption, photoluminescence and decay measurements. Using optical absorption spectra, Judd-Ofelt parameters were derived to determine the local structure and bonding in the vicinity of Sm 3+ ions. The emission spectra of Sm 3+ -doped BiP glass showed two intense emission bands, 4 G 5/2 → 6 H 7/2 (orange) and 4 G 5/2 → 6 H 9/2 (red) for which the stimulated emission cross-sections (σ e ) and branching ratios (β) were found to be higher. The quantum efficiencies were also calculated from decay measurements recorded for the 4 G 5/2 level of Sm 3+ ions. The suitable combination of Bi 2 O 3 (10 mol%) and Sm 3+ (0.5 mol%) ions in these glasses acted as an efficient lasing material and might be suitable for the development of visible orange-red photonic materials. Copyright © 2018 John Wiley & Sons, Ltd.

  20. Mg- and/or Sr-doped tricalcium phosphate/bioactive glass composites: Synthesis, microstructure and biological responsiveness

    Energy Technology Data Exchange (ETDEWEB)

    Bellucci, Devis, E-mail: devis.bellucci@unimore.it [Department of Engineering “E. Ferrari”, University of Modena and Reggio Emilia, Via Vignolese 905, 41125 Modena (Italy); Sola, Antonella [Department of Engineering “E. Ferrari”, University of Modena and Reggio Emilia, Via Vignolese 905, 41125 Modena (Italy); Cacciotti, Ilaria [University of Rome " Niccolò Cusano" , UdR INSTM, Via Don Carlo Gnocchi 3, 00166, Rome (Italy); Bartoli, Cristina; Gazzarri, Matteo [Department of Chemistry and Industrial Chemistry, University of Pisa, UdR INSTM — Pisa, Via Risorgimento 35, 56127 Pisa (Italy); Bianco, Alessandra [Department of Enterprise Engineering, INSTM RU “Rome-Tor Vergata”, Via del Politecnico 1, 00133 Roma (Italy); Chiellini, Federica [Department of Chemistry and Industrial Chemistry, University of Pisa, UdR INSTM — Pisa, Via Risorgimento 35, 56127 Pisa (Italy); Cannillo, Valeria [Department of Engineering “E. Ferrari”, University of Modena and Reggio Emilia, Via Vignolese 905, 41125 Modena (Italy)

    2014-09-01

    Presently, there is an increasing interest towards the composites of calcium phosphates, especially β-tricalcium phosphate (TCP), and bioactive glasses. In the present contribution, the recently developed BG{sub C}a/Mix glass has been used because its low tendency to crystallize allows to sinter the composites at relatively low temperature (i.e. 850 °C), thus minimizing the glass devitrification and the interaction with TCP. A further improvement is the introduction of lab-produced TCP powders doped with specific ions instead of non-doped commercial powders, since the biological properties of materials for bone replacement can be modulated by doping them with certain metallic ions, such as Mg and Sr. Therefore, novel binary composites have been produced by sintering the BG{sub C}a/Mix glass with the addition of pure, Mg-substituted, Sr-substituted or Mg/Sr bisubstituted TCP powders. After an accurate characterization of the starting TCP powders and of the obtained samples, the composites have been used as three-dimensional supports for the culture of mouse calvaria-derived pre-osteoblastic cells. The samples supported cell adhesion and proliferation and induced promising mechanisms of differentiation towards an osteoblastic phenotype. In particular, the Mg/Sr bi-doped samples seemed to better promote the differentiation process thus suggesting a combined stimulatory effect of Mg{sup 2+} and Sr{sup 2+} ions.

  1. Mg- and/or Sr-doped tricalcium phosphate/bioactive glass composites: Synthesis, microstructure and biological responsiveness

    International Nuclear Information System (INIS)

    Bellucci, Devis; Sola, Antonella; Niccolò Cusano, UdR INSTM, Via Don Carlo Gnocchi 3, 00166, Rome (Italy))" data-affiliation=" (University of Rome Niccolò Cusano, UdR INSTM, Via Don Carlo Gnocchi 3, 00166, Rome (Italy))" >Cacciotti, Ilaria; Bartoli, Cristina; Gazzarri, Matteo; Bianco, Alessandra; Chiellini, Federica; Cannillo, Valeria

    2014-01-01

    Presently, there is an increasing interest towards the composites of calcium phosphates, especially β-tricalcium phosphate (TCP), and bioactive glasses. In the present contribution, the recently developed BG C a/Mix glass has been used because its low tendency to crystallize allows to sinter the composites at relatively low temperature (i.e. 850 °C), thus minimizing the glass devitrification and the interaction with TCP. A further improvement is the introduction of lab-produced TCP powders doped with specific ions instead of non-doped commercial powders, since the biological properties of materials for bone replacement can be modulated by doping them with certain metallic ions, such as Mg and Sr. Therefore, novel binary composites have been produced by sintering the BG C a/Mix glass with the addition of pure, Mg-substituted, Sr-substituted or Mg/Sr bisubstituted TCP powders. After an accurate characterization of the starting TCP powders and of the obtained samples, the composites have been used as three-dimensional supports for the culture of mouse calvaria-derived pre-osteoblastic cells. The samples supported cell adhesion and proliferation and induced promising mechanisms of differentiation towards an osteoblastic phenotype. In particular, the Mg/Sr bi-doped samples seemed to better promote the differentiation process thus suggesting a combined stimulatory effect of Mg 2+ and Sr 2+ ions

  2. Physiological and morphological adaptations of herbaceous perennial legumes allow differential access to sources of varyingly soluble phosphate.

    Science.gov (United States)

    Pang, Jiayin; Yang, Jiyun; Lambers, Hans; Tibbett, Mark; Siddique, Kadambot H M; Ryan, Megan H

    2015-08-01

    The aim of this study was to investigate the capacity of three perennial legume species to access sources of varyingly soluble phosphorus (P) and their associated morphological and physiological adaptations. Two Australian native legumes with pasture potential (Cullen australasicum and Kennedia prostrata) and Medicago sativa cv. SARDI 10 were grown in sand under two P levels (6 and 40 µg P g(-1) ) supplied as Ca(H2 PO4 )2 ·H2 O (Ca-P, highly soluble, used in many fertilizers) or as one of three sparingly soluble forms: Ca10 (OH)2 (PO4 )6 (apatite-P, found in relatively young soils; major constituent of rock phosphate), C6 H6 O24 P6 Na12 (inositol-P, the most common form of organic P in soil) and FePO4 (Fe-P, a poorly-available inorganic source of P). All species grew well with soluble P. When 6 µg P g(-1) was supplied as sparingly soluble P, plant dry weight (DW) and P uptake were very low for C. australasicum and M. sativa (0.1-0.4 g DW) with the exception of M. sativa supplied with apatite-P (1.5 g). In contrast, K. prostrata grew well with inositol-P (1.0 g) and Fe-P (0.7 g), and even better with apatite-P (1.7 g), similar to that with Ca-P (1.9 g). Phosphorus uptake at 6 µg P g(-1) was highly correlated with total root length, total rhizosphere carboxylate content and total rhizosphere acid phosphatase (EC 3.1.3.2) activity. These findings provide strong indications that there are opportunities to utilize local Australian legumes in low P pasture systems to access sparingly soluble soil P and increase perennial legume productivity, diversity and sustainability. © 2014 Scandinavian Plant Physiology Society.

  3. Iron Phosphate Glass for Vitrifying Hanford AZ102 LAW in Joule Heated and Cold Crucible Induction Melters - 12240

    Energy Technology Data Exchange (ETDEWEB)

    Day, Delbert E.; Brow, Richard K.; Ray, Chandra S.; Reis, Signo T. [Missouri University of Science and Technology, 1870 Miner Circle, Rolla, MO 65409 (United States); Kim, Cheol-Woon [MO-SCI Corporation, 4040 HyPoint North, Rolla, MO 65401 (United States); Vienna, John D.; Sevigny, Gary [Pacific North West National Laboratory, Battelle Blvd., Richland, WA 99352 (United States); Peeler, David; Johnson, Fabienne C.; Hansen, Eric K. [Savannah River National Laboratory, Savannah River Site, 999-W, Aiken, SC 29803 (United States); Soelberg, Nick [Idaho National Laboratory, 2525 Fremont Avenue, Idaho Falls, ID 83415 (United States); Pegg, Ian L.; Gan, Hao [Catholic University of America, 620 Michigan Avenue, N.E., Washington, DC 20064 (United States)

    2012-07-01

    An iron phosphate composition for vitrifying a high sulfate (∼17 wt%) and high alkali (∼80 wt%) Hanford low activity waste (LAW), known as AZ-102 LAW, has been developed for processing in a Joule Heated Melter (JHM) or a Cold Crucible Induction Melter (CCIM). This composition produced a glass waste form, designated as MS26AZ102F-2, with a waste loading of 26 wt% of the AZ-102 which corresponded to a total alkali and sulfate (represented as SO{sub 3}) content of 21 and 4.4 wt%, respectively. A slurry (7 M Na{sup +}) of MS26AZ102F-2 simulant was melted continuously at temperatures between 1030 and 1090 deg. C for 10 days in a small JHM at PNNL and for 70 hours in a CCIM at INL. The as-cast glasses produced in both melters and in trial laboratory experiments along with their canister centerline cooled (CCC) counterparts met the requirements for the Product Consistency Test (PCT) and the Vapor Hydration Test (VHT) responses in the Hanford Tank Waste Treatment and Immobilization Plant (WTP) Contract. These glass waste forms retained up to 77 % of the SO{sub 3} (3.3 wt%), 100% of the Cesium, and 33 to 44% of the rhenium (used as a surrogate for Tc) all of which either exceeded or were comparable to the retention limit for these species in borosilicate glass nuclear waste form. Analyses of commercial K-3 refractory lining and the Inconel 693 metal electrodes used in JHM indicated only minimum corrosion of these components by the iron phosphate glass. This is the first time that an iron phosphate composition was melted continuously in a slurry fed JHM and in the US, thereby, demonstrating that iron phosphate glasses can be used as alternative hosts for vitrifying nuclear waste. The following conclusions are drawn from the results of the present work. (1) An iron phosphate composition, designated as MS26AZ102F-2, containing 26 wt% of the simulated high sulfate (17 wt%), high alkali (80 wt%) Hanford AZ-102 LAW meets all the criteria for processing in a JHM and CCIM. This

  4. Three-dimensional endothelial cell morphogenesis under controlled ion release from copper-doped phosphate glass.

    Science.gov (United States)

    Stähli, Christoph; James-Bhasin, Mark; Nazhat, Showan N

    2015-02-28

    Copper ions represent a promising angiogenic agent but are associated with cytotoxicity at elevated concentrations. Phosphate-based glasses (PGs) exhibit adjustable dissolution properties and allow for controlled ion release. This study examined the formation of capillary-like networks by SVEC4-10 endothelial cells (ECs) seeded in a three-dimensional (3D) type I collagen hydrogel matrix mixed with PG particles of the formulation 50P2O5-30CaO-(20-x)Na2O-xCuO (x=0 and 10 mol%). Copper and total phosphorus release decreased over time and was more sustained in the case of 10% CuO PG. Moreover, increasing the concentration of 10% CuO PG in collagen substantially delayed dissolution along with preferential release of copper. A 3D morphometric characterization method based on confocal laser scanning microscopy image stacks was developed in order to quantify EC network length, connectivity and branching. Network length was initially reduced in a concentration-dependent fashion by 10% CuO PG and, to a lesser extent, by 0% CuO PG, but reached values identical to the non-PG control by day 5 in culture. This reduction was attributed to a PG-mediated decrease in cell metabolic activity while cell proliferation as well as network connectivity and branching were independent of PG content. Gene expression of matrix metalloproteinases (MMP)-1 and -2 was up-regulated by PGs, indicating that MMPs did not play a critical role in network growth. The relationship between ion release and EC morphogenesis in 3D provided in this study is expected to contribute to an ultimately successful pro-angiogenic application of CuO-doped PGs. Copyright © 2015 Elsevier B.V. All rights reserved.

  5. Ac-conductivity and dielectric response of new zinc-phosphate glass/metal composites

    Energy Technology Data Exchange (ETDEWEB)

    Maaroufi, A., E-mail: maaroufi@fsr.ac.ma [University of Mohammed V, Laboratory of Composite Materials, Polymers and Environment, Department of Chemistry, Faculty of Sciences, P.B. 1014, Rabat-Agdal (Morocco); Oabi, O. [University of Mohammed V, Laboratory of Composite Materials, Polymers and Environment, Department of Chemistry, Faculty of Sciences, P.B. 1014, Rabat-Agdal (Morocco); Lucas, B. [XLIM UMR 7252 – Université de Limoges/CNRS, 123 avenue Albert Thomas, 87060 Limoges Cedex (France)

    2016-07-01

    The ac-conductivity and dielectric response of new composites based on zinc-phosphate glass with composition 45 mol%ZnO–55 mol%P{sub 2}O{sub 5}, filled with metallic powder of nickel (ZP/Ni) were investigated by impedance spectroscopy in the frequency range from 100 Hz to 1 MHz at room temperature. A high percolating jump of seven times has been observed in the conductivity behavior from low volume fraction of filler to the higher fractions, indicating an insulator – semiconductor phase transition. The measured conductivity at higher filler volume fraction is about 10{sup −1} S/cm and is frequency independent, while, the obtained conductivity for low filler volume fraction is around 10{sup −8} S/cm and is frequency dependent. Moreover, the elaborated composites are characterized by high dielectric constants in the range of 10{sup 5} for conductive composites at low frequencies (100 Hz). In addition, the distribution of the relaxation processes was also evaluated. The Debye, Cole-Cole, Davidson–Cole and Havriliak–Negami models in electric modulus formalism were used to model the observed relaxation phenomena in ZP/Ni composites. The observed relaxation phenomena are fairly simulated by Davidson–Cole model, and an account of the interpretation of results is given. - Highlights: • Composites of ZnO-P{sub 2}O{sub 5}/metal were investigated by impedance spectroscopy. • Original ac-conductivity behavior was discovered in ZnO-P{sub 2}O{sub 5}/metal composites. • High dielectric constant is measured in ZnO-P{sub 2}O{sub 5}/metal composites. • Dielectric constant as filler function is well interpreted with percolation theory. • Observed relaxation processes are well described using electric modulus formalism.

  6. Towards modular bone tissue engineering using Ti-Co-doped phosphate glass microspheres: cytocompatibility and dynamic culture studies.

    Science.gov (United States)

    Peticone, Carlotta; De Silva Thompson, David; Owens, Gareth J; Kim, Hae-Won; Micheletti, Martina; Knowles, Jonathan C; Wall, Ivan

    2017-09-01

    The production of large quantities of functional vascularized bone tissue ex vivo still represent an unmet clinical challenge. Microcarriers offer a potential solution to scalable manufacture of bone tissue due to their high surface area-to-volume ratio and the capacity to be assembled using a modular approach. Microcarriers made of phosphate bioactive glass doped with titanium dioxide have been previously shown to enhance proliferation of osteoblast progenitors and maturation towards functional osteoblasts. Furthemore, doping with cobalt appears to mimic hypoxic conditions that have a key role in promoting angiogenesis. This characteristic could be exploited to meet the clinical requirement of producing vascularized units of bone tissue. In the current study, the human osteosarcoma cell line MG-63 was cultured on phosphate glass microspheres doped with 5% mol titanium dioxide and different concentrations of cobalt oxide (0%, 2% and 5% mol), under static and dynamic conditions (150 and 300 rpm on an orbital shaker). Cell proliferation and the formation of aggregates of cells and microspheres were observed over a period of two weeks in all glass compositions, thus confirming the biocompatibility of the substrate and the suitability of this system for the formation of compact micro-units of tissue. At the concentrations tested, cobalt was not found to be cytotoxic and did not alter cell metabolism. On the other hand, the dynamic environment played a key role, with moderate agitation having a positive effect on cell proliferation while higher agitation resulting in impaired cell growth. Finally, in static culture assays, the capacity of cobalt doping to induce vascular endothelial growth factor (VEGF) upregulation by osteoblastic cells was observed, but was not found to increase linearly with cobalt oxide content. In conclusion, Ti-Co phosphate glasses were found to support osteoblastic cell growth and aggregate formation that is a necessary precursor to tissue

  7. Pectin/anhydrous dibasic calcium phosphate matrix tablets for in vitro controlled release of water-soluble drug.

    Science.gov (United States)

    Mamani, Pseidy Luz; Ruiz-Caro, Roberto; Veiga, María Dolores

    2015-10-15

    Different pectin/anhydrous dibasic calcium phosphate (ADCP) matrix tablets have been developed in order to obtain controlled release of a water-soluble drug (theophylline). Swelling, buoyancy and dissolution studies have been carried out in different aqueous media (demineralized water, progressive pH medium, simulated gastric fluid, simulated intestinal fluid and simulated colonic fluid), to characterize the matrix tablets. When the pectin/ADCP ratio was ≥0.26 (P1, P2, P3 and P4 tablets) a continuous swelling and low theophylline dissolution rate from the matrices were observed. So, pectin gel forming feature predominated over the ADCP properties, yielding pH-independent drug release behavior from these matrices. On the contrary, pectin/ADCP ratios ≤0.11 (P5 and P6 tablets) allowed to achieve drug dissolution pH dependent. Consequently, the suitable selection of the pectin/ADCP ratio will allow to tailor matrix tablets for controlled release of water-soluble drugs in a specific manner in the gastrointestinal tract. Copyright © 2015 Elsevier B.V. All rights reserved.

  8. A decreased soluble Klotho level with normal eGFR, FGF23, serum phosphate, and FEP in an ADPKD patient with enlarged kidneys due to multiple cysts.

    Science.gov (United States)

    Kanai, Takahiro; Shiizaki, Kazuhiro; Betsui, Hiroyuki; Aoyagi, Jun; Yamagata, Takanori

    2018-05-16

    Autosomal dominant polycystic kidney disease (ADPKD) is the most common hereditary renal disorder. ADPKD is characterized clinically by the presence of multiple bilateral renal cysts that lead to chronic renal failure. The cysts evolve from renal tubular epithelial cells that express the Klotho gene. Notably, Klotho acts as a co-receptor for fibroblast growth factor 23 (FGF23); in this context, it induces phosphaturia and maintains serum phosphate at a normal level. Many reports have shown that decreases in the soluble Klotho level and increases in the FGF23 level are associated with glomerular filtration rate (GFR) decline, but a recent study observed these changes in patient with normal eGFR. It remains unclear whether the decrease in the Klotho level precedes the increase in FGF23. Here, we present an ADPKD patient with enlarged kidneys due to multiple cysts who had a decreased soluble Klotho level but a normal eGFR and a normal FGF23 level. The patient's serum phosphate level was normal, as was the fractional excretion of phosphate (FEP). This appears to be the first reported case to show a decreased soluble Klotho level plus normal eGFR, FGF23, and FEP. These results suggest that Klotho decreases before FGF23 increases and further suggest that Klotho is not required to maintain normal serum phosphate levels in ADPKD if the FEP and serum phosphate levels are normal.

  9. Solubility and transport measurements as tools for the speciation of f-elements at tracer-scale amounts; application to Eu and Th in phosphate media

    International Nuclear Information System (INIS)

    Fourest, B.; David, F.; Lagarde, G.; Lindecker, C.; Du, J.F. Le; Tarapcik, P.; Trskova, R.

    1998-01-01

    The speciation of f-elements can be examined by methods which are based either on the distribution of the radionuclide of interest between two phases (solubility measurements) or on its moving in solution (capillary diffusion and migration). Predictive curves giving the variation of the mobility and the concentration of Europium as a function of pH and/or phosphate concentration can be proposed from selected literature data. Capillary electrophoresis experiments show that the mobility decrease due to hydrolysis occurs at a pH value lower than expected. The peak intensity is correspondingly smaller, but this observation cannot be simply related to a change in the charge of the migrating species because of sorption and precipitation phenomena on the capillary walls. Diffusion coefficient measurements by the 'open end capillary' method confirm the formation of larger and/or less charged species starting at a similar pH value. In the presence of phosphate anions, both transport methods should indicate the presence in solution of species having a larger size than expected, which could be polynuclear. Solubility measurements give more information but require the synthesis of a well-defined labelled phosphate compound. The total concentration of f-elements detected in the solutions equilibrated with such compounds allow to deduce, by varying only one parameter in the solution (pH or phosphate concentration), the form and the charge of the different species prevailing in the solution. The solubility method appears particularly interesting in the case of concentrated phosphate media

  10. Photosensitivity of the Er/Yb-Codoped Schott IOG1 Phosphate Glass Using 248 nm, Femtosecond, and Picosecond Laser Radiation

    International Nuclear Information System (INIS)

    Pissadakis, S.; Michelakaki, I.

    2009-01-01

    The effect of 248 nm laser radiation, with pulse duration of 5 picoseconds, 500 femtosecond, and 120 femtosecond, on the optical properties and the Knoop hardness of a commercial Er/Yb-codoped phosphate glass is presented here. Refractive index changes of the order of few parts of 10-4 are correlated with optical absorption centers induced in the glass volume, using Kramers-Kroning relationship. Accordingly, substantially lower refractive index changes are measured in volume Bragg gratings inscribed in the glass, indicating that, in addition to the optical density changes, volume dilation changes of negative sign may also be associated with the 248 nm ultrafast irradiation. The Knoop hardness experimental results reveal that the glass matrix undergoes an observable initial hardening and then a reversing softening and volume dilation process for modest accumulated energy doses, where the Knoop hardness follows a nonmonotonic trend. Comparative results on the Knoop hardness trend are also presented for the case of 193 nm excimer laser radiation. The above findings denote that the positive or negative evolution of refractive index changes induced by the 248 0nm ultrafast radiation in the glass is dominated by the counteraction of the color center formation and the volume modification effects.

  11. An alternative host matrix based on iron phosphate glasses for the vitrification of specialized nuclear waste forms. Annual progress report, September 15, 1996 - September 14, 1997

    International Nuclear Information System (INIS)

    Day, D.E.; Marasinghe, K.; Ray, C.S.

    1997-01-01

    'Objectives of this project are to: (1) investigate the glass composition and processing conditions that yield optimum properties for iron phosphate glasses for vitrifying radioactive waste, (2) determine the atomic structure of iron phosphate glasses and the structure-property relationships, (3) determine how the physical and structural properties of iron phosphate glasses are affected by the addition of simulated high level nuclear waste components, and (4) investigate the process and products of devitrification of iron phosphate waste forms. The glass forming ability of about 125 iron phosphate melts has been investigated in different oxidizing to reducing atmospheres using various iron oxide raw materials such as Fe 2 O 3 , FeO, Fe 3 O 4 , and FeC 2 O 4 2H 2 O. The chemical durability, redox equilibria between Fe(II) and Fe(III), crystallization behavior and structural features for these glasses and their crystalline forms have been investigated using a variety of techniques including Mossbauer spectroscopy, X-ray absorption spectroscopy (XAS), X-ray photoelectron spectroscopy (XPS), Extended x-ray absorption fine structure (EXAFS) and X-ray absorption near edge structure (XANES) analysis, differential thermal and thermogravimetric analysis (DTA/TGA), and X-ray and neutron diffraction.'

  12. The local structure and magnetic interactions between Fe3+ and V4+ ions in lithium–phosphate glasses

    International Nuclear Information System (INIS)

    Andronache, Constantin I.

    2012-01-01

    Electron Paramagnetic Resonance (EPR) provides a useful tool not only as a probe of local structure and short range order in glasses, but also of magnetic interactions in the glasses containing suitable magnetic ions. We have analyzed the spectra of xFe 2 O 3 ·(100 − x)[P 2 O 5 ·Li 2 O] and x(Fe 2 O 3 ·V 2 O 5 )·(100 − x)[P 2 O 5 ·Li 2 O] glass systems, with 0 2 O 5 ·Li 2 O] stands for 50Li 2 O·50P 2 O 5 glass composition. For samples x > 50 mol % a study indicates the presence of crystalline α Fe 2 O 3 in the glasses. Observed spectra have resonance lines centered at g ∼ 4.3 and g ∼ 2.0 typical for Fe 3+ and V 4+ ions present in the oxide glasses. For low contend of transition metal (TM) oxides (Fe 2 O 3 or V 2 O 5 ·Fe 2 O 3 ) the spectra present a hyperfine structure typical for isolated V 4+ ions. With the increasing of TM content, the EPR absorption signal showing hyperfine structure superposed by a broad line without hyperfine structure characteristic for clustered ions. At high TM content, the vanadium hyperfine structure disappears and only the broad line can be observed in the spectra. -- Highlights: ► Lithium phosphate glass with Fe and V ions were investigated by means of EPR. ► The composition dependence of line intensity were investigated. ► The spin Hamiltonian parameters for VO 2+ were evaluated.

  13. Structural and physico-chemical analysis of calcium/strontium substituted, near-invert phosphate based glasses for biomedical applications.

    Science.gov (United States)

    Patel, U; Moss, R M; Hossain, K M Z; Kennedy, A R; Barney, E R; Ahmed, I; Hannon, A C

    2017-09-15

    Neutron diffraction, 23 Na and 31 P NMR, and FTIR spectroscopy have been used to investigate the structural effects of substituting CaO with SrO in a 40P 2 O 5 ·(16-x)CaO·20Na 2 O·24MgO·xSrO glass, where x is 0, 4, 8, 12 and 16mol%. The 31 P solid-state NMR results showed similar amounts of Q 1 and Q 2 units for all of the multicomponent glasses investigated, showing that the substitution of Sr for Ca has no effect on the phosphate network. The M-O coordinations (M=Mg, Ca, Sr, Na) were determined for binary alkali and alkaline earth metaphosphates using neutron diffraction and broad asymmetric distributions of bond length were observed, with coordination numbers that were smaller and bond lengths that were shorter than in corresponding crystals. The Mg-O coordination number was determined most reliably as 5.0(2). The neutron diffraction results for the multicomponent glasses are consistent with a structural model in which the coordination of Ca, Sr and Na is the same as in the binary metaphosphate glass, whereas there is a definite shift of Mg-O bonds to longer distance. There is also a small but consistent increase in the Mg-O coordination number and the width of the distribution of Mg-O bond lengths, as Sr substitutes for Ca. Functional properties, including glass transition temperatures, thermal processing windows, dissolution rates and ion release profiles were also investigated. Dissolution studies showed a decrease in dissolution rate with initial addition of 4mol% SrO, but further addition of SrO showed little change. The ion release profiles followed a similar trend to the observed dissolution rates. The limited changes in structure and dissolution rates observed for substitution of Ca with Sr in these fixed 40mol% P 2 O 5 glasses were attributed to their similarities in terms of ionic size and charge. Phosphate based glasses are extremely well suited for the delivery of therapeutic ions in biomedical applications, and in particular strontium plays an

  14. Eigenstates and radiative transition probabilities for Tm3+(4f12) in phosphate and tellurite glasses

    International Nuclear Information System (INIS)

    Spector, N.; Reisfeld, R.; Boehm, L.

    1977-01-01

    Electronic wavefunctions of Tm 3+ in intermediate coupling were obtained and used to calculate the Usup((lambda)) matrix elements between all possible states of the 4f 12 configuration. The Judd-Ofelt intensity parameters Ωsub(lambda) obtained for Tm 3+ in phosphate and tellurite glasses were used in conjunction with the Usup((lambda))'s to calculate the forced electric dipole line strengths. The total electric and magnetic radiative transition probabilities are calculated. The entire theoretical spectrum involving the ground and excited levels (from 129 nm to 16447 nm) is given. (Auth.)

  15. UV-assisted selective chemical etching of relief gratings in Er/Yb-codoped IOG1 phosphate glass

    Energy Technology Data Exchange (ETDEWEB)

    Pappas, C; Pissadakis, S [Foundation for Research and Technology-Hellas, Institute of Electronic Structure and Laser, Vasilika Vouton, PO Box 1527, Heraklion 71 110, GREECE (Greece)

    2007-04-15

    The patterning of sub-micron periodicity Bragg reflectors in Er/Yb-codoped IOG1, phosphate glass is demonstrated. A high yield patterning technique is presented, wherein high volume damage is induced into the glass matrix by exposure to intense UV radiation, and subsequently a chemical development in a strong acid selectively etches the exposed areas. The grating reflectors were fabricated by employing an elliptical Talbot interferometer and the output of a 213nm, 150ps frequency quintupled Nd:YAG laser. The grating depth of the etched relief pattern in time was measured at fixed time intervals and the dependence is presented in upon the etching time and exposure conditions. The gratings fabricated are examined by atomic and scanning electron microscopy for revealing the topology of the relief structure. Gratings with period of the order of 500nm were fabricated, having a maximum depth of 60nm.

  16. Effects of titanium nanoparticles on self-cleaning and structural features of zinc-magnesium-phosphate glass

    International Nuclear Information System (INIS)

    Ismail, S.F.; Sahar, M.R.; Ghoshal, S.K.

    2016-01-01

    Graphical abstract: Water contact angle for sample S2, S3, S4 and S5. The water contact angle increased with increased the titanium NPs content (mol%). - Highlights: • ZnO–MgO–P_2O_5 embedded TiO_2 NPs prepared by conventional melt-quenching method. • The amorphous nature is confirmed by X-ray diffraction spectroscopy. • The structural characteristics of glasses is investigated using FTIR and Raman. • Wettability of the glasses surface by water contact angle. - Abstract: The loss of glass transparency on surface pollutants contamination unless inhibited not only causes vision obscurity but also responsible for major aesthetic damages of cultural heritage. It is due to the sticking of fine dirt particles on wetting layers, a complex process with several possible ramifications still to be clarified. We report the influence of titanium dioxide or titania (TiO_2) nanoparticles (NPs) on the structural and self-cleaning properties of zinc–magnesium–phosphate glasses. Following melt-quenching method glass samples of optimized composition (42 − x)P_2O_5–8MgO–50ZnO–xTiO_2 with x = 0, 1, 2, 3 and 4 mol% are prepared. XRD patterns verified their amorphous nature and TEM images revealed the nucleation of TiO_2 NPs of average diameter ≈4.05 ± 0.01 nm. Fourier transform infrared (FTIR) spectra displayed four absorption band centred at 1618–3438 cm"−"1, 902– 931 cm"−"1, 757–762 cm"−"1 and 531–560 cm"−"1. Raman spectra exhibited four peaks each accompanied by a blue-shift. Water contact angle is found to increase with the increase of titanium NPs concentration into the amorphous matrix. This knowledge can be used to set up strategies and selective treatments to preventing glass transparency loss via the modification of self-cleaning attributes.

  17. Structural and luminescence studies of Ho{sup 3+}-doped zinc-aluminium-sodium-phosphate (ZANP) glasses

    Energy Technology Data Exchange (ETDEWEB)

    Brahmachary, K.; Rajesh, D.; Ratnakaram, Y. C., E-mail: ratnakaramsvu@gmail.com [Department of Physics, Sri Venkateswara University, Tirupati-517502 (India)

    2015-06-24

    Trivalent holmium doped zinc-aluminium-sodium-phosphate (ZANP) glasses were prepared by conventional melt-quenching technique and characterized for their structural and luminescence properties. The amorphous nature, elemental analysis and thermal stability of the glasses were studied by using X-ray diffraction, energy dispersive spectrum and differential scanning calorimetry analysis, respectively. The absorption and fluorescence spectra have been recorded at room temperature. Based on the absorption spectra, the Judd-Ofelt parameters and radiative parameters such as spontaneous transition probabilities (A{sub R}), branching ratios (β{sub R}), radiative lifetimes (τ{sub R}) were calculated and discussed. From the emission spectra emission peak positions (λ{sub P}), effective bandwidths (Δλ{sub eff}) and stimulated emission cross-sections (σ{sub P}) were calculated for the observed emission transitions,{sup 5}S{sub 2} ({sup 5}F{sub 4}→{sup 5}I{sub 8}) and {sup 5}F{sub 5}→{sup 5}I{sub 8} in all the glass samples. The stimulated emission cross-section is higher for ZANPHo10 glass matrix and so it may be useful for laser excitation.

  18. Effect of laser irradiation on the structure and valence states of copper in Cu-phosphate glass by XPS studies

    International Nuclear Information System (INIS)

    Khattak, G.D.; Mekki, A.; Gondal, M.A.

    2010-01-01

    The effect of laser irradiation using three different wavelengths (IR, visible and UV) generated from Nd:YAG laser on the local glass structure as well as on the valence state of the copper ions in copper phosphate glass containing CuO with the nominal composition 0.30(CuO)-(0.70)(P 2 O 5 ), has been investigated by X-ray photoelectron spectroscopy (XPS). The presence of asymmetry and satellite peaks in the Cu 2p spectrum for the unirradiated sample is an indication of the presence of two different valence states, Cu 2+ and Cu + . Hence, the Cu 2p 3/2 spectrum was fitted to two Gaussian-Lorentzian peaks and the corresponding ratio, Cu 2+ /Cu total , determined from these relative areas clearly shows that copper ions exist predominately (>86%) in the Cu 2+ state for the unirradiated glass sample under investigation. For the irradiated samples the symmetry and the absence of satellite peaks in the Cu 2p spectra indicate the existence of the copper ions mostly in Cu + state. The O 1s spectra show slight asymmetry for the irradiated as well as unirradiated glass samples which result from two contributions, one from the presence of oxygen atoms in the P-O-P environment (bridging oxygen BO) and the other from oxygen in an P-O-Cu and P=O environment (non-bridging oxygen NBO). The ratio of NBO to total oxygen was found to increase with laser power.

  19. Raman and optical absorption spectroscopic investigation of Yb-Er codoped phosphate glasses containing SiO2

    Institute of Scientific and Technical Information of China (English)

    Youkuo Chen; Lei Wen; Lili Hu; Wei Chen; Y. Guyot; G. Boulon

    2009-01-01

    Yb-Er codoped Na2O-Al2O3-P2Os-xSiO2 glasses containing 0 鈥? 20 mol% SiO2 were prepared successfully. The addition of SiO2 to the phosphate glass not only lengthens the bond between P5+ and non-bridging oxygen but also reduces the number of P=O bond. In contrast with silicate glass in which there is only four-fold coordinated Si4+, most probably there coexist [SiO4] tetrahedron and [SiO6] octahedron in our glasses. Within the range of 0 鈥? 20 mol% SiO2 addition, the stimulated emission cross-section of Er3+ ion only decreases no more than 10%. The Judd-Ofelt intensity parameters of Er3+, 惟.2 does not change greatly, but 惟74 and 惟6 decrease obviously with increasing SiO2 addition, because the bond between Er + and O2- is more strongly covalently bonded.

  20. Radiative properties and luminescence spectra of Sm{sup 3+} ion in zinc–aluminum–sodium-phosphate (ZANP) glasses

    Energy Technology Data Exchange (ETDEWEB)

    Brahmachary, K.; Rajesh, D.; Ratnakaram, Y.C., E-mail: ratnakaramsvu@gmail.com

    2015-05-15

    The fluorescence properties of different concentrations of Sm{sup 3+} doped zinc–aluminum–sodium-phosphate (ZANP) glasses were studied by the XRD, SEM, FTIR, TG–DTA, optical absorption, photoluminescence and decay cure analysis. X-ray diffraction profiles and SEM images confirmed the amorphous nature of the glass samples. Structural information of these glass matrices was provided by FTIR spectrum. Judd–Ofelt (J–O) theory was applied to the experimental oscillator strengths to evaluate three phenomenological J–O intensity parameters, Ω{sub λ} (λ=2, 4 and 6). Using J–O intensity parameters and emission spectra, various radiative parameters such as radiative transition probabilities (A{sub R}), radiative lifetimes (τ{sub R}), calculated and measured branching ratios (β{sub R} and β{sub m}), effective bandwidths (Δλ{sub eff}) and stimulated emission cross-sections (σ{sub P}) were calculated for observed emission transitions. The intensity of emission transitions with the variation of Sm{sup 3+} ion concentration was studied. The nature of decay curves of {sup 4}G{sub 5/2} level for different Sm{sup 3+} ion concentrations in ZANP glass was analyzed and obtained measured lifetimes (τ{sub exp}). Quantum efficiency of {sup 4}G{sub 5/2} level was calculated based on experimental and measured radiative lifetimes (τ{sub exp} and τ{sub R}). - Highlights: • The amorphous nature of glasses was confirmed due to lack of sharp peaks in the XRD profiles. • Higher covalency and rigidity were obtained in ZANPSm05 and ZANPSm15 glass matrices respectively. • The symmetric nature present in ZANP glass matrix is confirmed from MD transition, {sup 4}G{sub 5/2}→{sup 6}H{sub 7/2} of Sm{sup 3+} ion. • The decrease of intensity of emission transitions beyond 0.5 mol% is attributed to dipole–dipole interactions. • Among all the glass matrices studied, all the spectroscopic parameters are higher in ZANPSm05 glass matrix.

  1. Laser Machining and In Vitro Assessment of Wollastonite-Tricalcium Phosphate Eutectic Glasses and Glass-Ceramics

    Directory of Open Access Journals (Sweden)

    Daniel Sola

    2018-01-01

    Full Text Available Bioactivity and ingrowth of ceramic implants is commonly enhanced by a suitable interconnected porous network. In this work, the laser machining of CaSiO3‒Ca3(PO42 biocompatible eutectic glass-ceramics and glasses was studied. For this purpose, 300 µm diameter craters were machined by using pulsed laser radiation at 532 nm with a pulsewidth in the nanosecond range. Machined samples were soaked in simulated body fluid for 2 months to assess the formation of a hydroxyapatite layer on the surface of the laser machined areas. The samples were manufactured by the laser floating zone technique using a CO2 laser. Morphology, composition and microstructure of the machined samples were described by Field Emission Scanning Electron Microscopy, Energy Dispersive X-ray Spectroscopy and micro-Raman Spectroscopy.

  2. Thermal, structural and magnetic properties of some zinc phosphate glasses doped with manganese ions

    International Nuclear Information System (INIS)

    Pascuta, Petru; Bosca, Maria; Borodi, Gheorghe; Culea, Eugen

    2011-01-01

    Research highlights: → MnO) x .(P 2 O 5 ) 40 .(ZnO) 60-x glasses (0 ≤ x ≤ 20 mol%) were prepared by the melt-quenching technique. → The DTA data indicate a good thermal stability of the studied glasses. → EPR spectra shows isolated Mn 2+ ions in octahedral symmetric sites or to associated ones when the Mn 2+ ions are involved in dipole-dipole and/or superexchange interactions. → The magnetic susceptibility data revealed superexchange magnetic interactions involving manganese ions, antiferromagnetically coupled for the sample containing 20 mol% MnO. - Abstract: (MnO) x .(P 2 O 5 ) 40 .(ZnO) 60-x glasses containing different concentrations of MnO ranging from 0 to 20 mol% were prepared by the melt-quenching technique. The samples had a fixed P 2 O 5 content of 40 mol% and the MnO:ZnO ratio was varied. The thermal, structural and magnetic properties of these glasses were investigated by means of differential thermal analysis (DTA), electron paramagnetic resonance (EPR) and magnetic susceptibility measurements. Compositional dependence of the glass transition (T g ), crystallization (T p ) and melting temperatures were determined by DTA investigations. From the dependence of the T g on the heating rate (a), the activation energy of the glass transition (E g ) was calculated. The fragility index (F) for the studied glasses was determined to see whether these materials are obtained from kinetically strong-glass-forming (KS) or kinetically fragile-glass forming (KF) liquids. The EPR spectra of the studied glasses revealed absorptions centered at g ∼ 2.0, 3.3 and 4.3. The compositional variations of the intensity and line width of these absorption lines was interpreted in terms of the variation in the concentration of the Mn 2+ and Mn 3+ ions in the glass and the interaction between the manganese ions. EPR and magnetic susceptibility data reveal that both Mn 2+ and Mn 3+ ions are present in the studied glasses, their relative concentration being dependent on

  3. A New Biocompatible and Antibacterial Phosphate Free Glass-Ceramic for Medical Applications

    Science.gov (United States)

    Cabal, Belén; Alou, Luís; Cafini, Fabio; Couceiro, Ramiro; Sevillano, David; Esteban-Tejeda, Leticia; Guitián, Francisco; Torrecillas, Ramón; Moya, José S.

    2014-01-01

    In the attempt to find valid alternatives to classic antibiotics and in view of current limitations in the efficacy of antimicrobial-coated or loaded biomaterials, this work is focused on the development of a new glass-ceramic with antibacterial performance together with safe biocompatibility. This bactericidal glass-ceramic composed of combeite and nepheline crystals in a residual glassy matrix has been obtained using an antimicrobial soda-lime glass as a precursor. Its inhibitory effects on bacterial growth and biofilm formation were proved against five biofilm-producing reference strains. The biocompatibility tests by using mesenchymal stem cells derived from human bone indicate an excellent biocompatibility. PMID:24961911

  4. A New Biocompatible and Antibacterial Phosphate Free Glass-Ceramic for Medical Applications

    Science.gov (United States)

    Cabal, Belén; Alou, Luís; Cafini, Fabio; Couceiro, Ramiro; Sevillano, David; Esteban-Tejeda, Leticia; Guitián, Francisco; Torrecillas, Ramón; Moya, José S.

    2014-06-01

    In the attempt to find valid alternatives to classic antibiotics and in view of current limitations in the efficacy of antimicrobial-coated or loaded biomaterials, this work is focused on the development of a new glass-ceramic with antibacterial performance together with safe biocompatibility. This bactericidal glass-ceramic composed of combeite and nepheline crystals in a residual glassy matrix has been obtained using an antimicrobial soda-lime glass as a precursor. Its inhibitory effects on bacterial growth and biofilm formation were proved against five biofilm-producing reference strains. The biocompatibility tests by using mesenchymal stem cells derived from human bone indicate an excellent biocompatibility.

  5. Comparison of lead removal behaviors and generation of water-soluble sodium compounds in molten lead glass under a reductive atmosphere

    Science.gov (United States)

    Okada, Takashi; Nishimura, Fumihiro; Xu, Zhanglian; Yonezawa, Susumu

    2018-06-01

    We propose a method of reduction-melting at 1000 °C, using a sodium-based flux, to recover lead from cathode-ray tube funnel glass. To recover the added sodium from the treated glass, we combined a reduction-melting process with a subsequent annealing step at 700 °C, generating water-soluble sodium compounds in the molten glass. Using this combined process, this study compares lead removal behavior and the generation of water-soluble sodium compounds (sodium silicates and carbonates) in order to gain fundamental information to enhance the recovery of both lead and sodium. We find that lead removal increases with increasing melting time, whereas the generation efficiency of water-soluble sodium increases and decreases periodically. In particular, near 90% lead removal, the generation of water-soluble sodium compounds decreased sharply, increasing again with the prolongation of melting time. This is due to the different crystallization and phase separation efficiencies of water-soluble sodium in molten glass, whose structure continuously changes with lead removal. Previous studies used a melting time of 60 min in the processes. However, in this study, we observe that a melting time of 180 min enhances the water-soluble sodium generation efficiency.

  6. Fabrication of planar optical waveguides by 6.0 MeV silicon ion implantation in Nd-doped phosphate glasses

    Science.gov (United States)

    Shen, Xiao-Liang; Dai, Han-Qing; Zhang, Liao-Lin; Wang, Yue; Zhu, Qi-Feng; Guo, Hai-Tao; Li, Wei-Nan; Liu, Chun-Xiao

    2018-04-01

    We report the fabrication of a planar optical waveguide by silicon ion implantation into Nd-doped phosphate glass at an energy of 6.0 MeV and a dose of 5.0 × 1014 ions/cm2. The change in the surface morphology of the glass after the implantation can be clearly observed by scanning electron microscopy. The measurement of the dark mode spectrum of the waveguide is conducted using a prism coupler at 632.8 nm. The refractive index distribution of the waveguide is reconstructed by the reflectivity calculation method. The near-field optical intensity profile of the waveguide is measured using an end-face coupling system. The waveguide with good optical properties on the glass matrix may be valuable for the application of the Nd-doped phosphate glass in integrated optical devices.

  7. Efficiency of ammonium nitrate phosphates of varying water-soluble phosphorus content for rice and succeeding maize crop on contrasting soil types

    International Nuclear Information System (INIS)

    Bhujbal, B.M.; Mistry, K.B.; Chapke, V.G.; Mutatkar, V.K.

    1977-01-01

    Efficiency of ammonium nitrate phosphates (ANP) containing 30 and 50 percent of water-soluble phosphorus (W.S.P.) vis-a-vis that of entirely water-soluble monoammonium orthophosphate (MAP) for rice and succeeding maize crop on phosphate responsive laterite, red sandy loam (Chalka) and calcareous black soils was examined in greenhouse experiments. Data on dry matter yield, uptake of phosphorus, utilization of applied fertilizer, 'Effective Rate of Application' and 'Relative Efficiency percent' at flowering stage of rice indicated no significant differences between ammonium nitrate phosphate (30 percent and 50 percent water-soluble ohosphorus) and monoammonium orthophosphate (MAP) on laterits and natural red sandy loam soils. MAP was significantly superior to the two ANP fertilizers on calcareous black soil; no significant differences were observed between ANP (30 percent W.S.P.) and ANP (50 percent W.S.P.) on this soil. The succeeding maize crop grown up to flowering in the same pots indicated that the residual value of ANP (30 percent W.S.P.) was equal or superior to that of MAP on the laterits as well as calcareous black soil. No significant differences were detected between the residual values of the two water-solubility grades of ANP. Incubation under submerged conditions for periods upto 60 days showed that 0.5 M NaHCO 3 (pH 8.5) extractable phosphorus (plant-available phosphate) in the ANP (30 percent W.S.P.) treatment was, in general, equal to those in the MAP treatments in the laterite and red sandy loam but was significantly lower in the calcareous black soil. No marked differences were observed between the effects of the two ANP fertilizers. (author)

  8. Efficiency of ammonium nitrate phosphates of varying water-soluble phosphorus content for rice and succeeding maize crop on contrasting soil types. [/sup 32/P-labelled fertilizers

    Energy Technology Data Exchange (ETDEWEB)

    Bhujbal, B M; Mistry, K B [Bhabha Atomic Research Centre, Bombay (India). Biology and Agriculture Div.; Chapke, V G; Mutatkar, V K [Fertilizer Corp. of India Ltd., Bombay

    1977-09-01

    Efficiency of ammonium nitrate phosphates (ANP) containing 30 and 50 percent of water-soluble phosphorus (W.S.P.) vis-a-vis that of entirely water-soluble monoammonium orthophosphate (MAP) for rice and succeeding maize crop on phosphate responsive laterite, red sandy loam (Chalka) and calcareous black soils was examined in greenhouse experiments. Data on dry matter yield, uptake of phosphorus, utilization of applied fertilizer, 'Effective Rate of Application' and 'Relative Efficiency percent' at flowering stage of rice indicated no significant differences between ammonium nitrate phosphate (30 percent and 50 percent water-soluble ohosphorus) and monoammonium orthophosphate (MAP) on laterits and natural red sandy loam soils. MAP was significantly superior to the two ANP fertilizers on calcareous black soil; no significant differences were observed between ANP (30 percent W.S.P.) and ANP (50 percent W.S.P.) on this soil. The succeeding maize crop grown up to flowering in the same pots indicated that the residual value of ANP (30 percent W.S.P.) was equal or superior to that of MAP on the laterits as well as calcareous black soil. No significant differences were detected between the residual values of the two water-solubility grades of ANP. Incubation under submerged conditions for periods upto 60 days showed that 0.5 M NaHCO/sub 3/ (pH 8.5) extractable phosphorus (plant-available phosphate) in the ANP (30 percent W.S.P.) treatment was, in general, equal to those in the MAP treatments in the laterite and red sandy loam but was significantly lower in the calcareous black soil. No marked differences were observed between the effects of the two ANP fertilizers.

  9. Research and development of improving the pumping efficiency of phosphate laser glass: Final report

    International Nuclear Information System (INIS)

    Izumitani, T.

    1985-01-01

    It is well known that Pt inclusion in laser glass remarkably lowers the damage threshold by laser beam. Present commercial laser glasses are produced so as to minimize the Pt inclusion. However, the damage due to small Pt inclusion, which has never seriously caused the laser damage in a lower fluence level, is getting to be a problem as the output fluence of laser increases. In NOVA system, most of laser glasses were damaged at fluence of 3 to 4 J/cm 2 . Since NOVA has been planned to operate at 10 J/cm 2 , this damage threshold is absolutely unacceptable and it should be increased. In this report we will show the basic conception to make a Pt inclusion free glass and its experimental results

  10. Sodium aluminum-iron phosphate glass-ceramics for immobilization of lanthanide oxide wastes from pyrochemical reprocessing of spent nuclear fuel

    Science.gov (United States)

    Stefanovsky, S. V.; Stefanovsky, O. I.; Kadyko, M. I.; Nikonov, B. S.

    2018-03-01

    Sodium aluminum (iron) phosphate glass ceramics containing of up to 20 wt.% rare earth (RE) oxides simulating pyroprocessing waste were produced by melting at 1250 °C followed by either quenching or slow cooling to room temperature. The iron-free glass-ceramics were composed of major glass and minor phosphotridymite and monazite. The iron-bearing glass-ceramics were composed of major glass and minor monazite and Na-Al-Fe orthophosphate at low waste loadings (5-10 wt.%) and major orthophosphate and minor monazite as well as interstitial glass at high waste loadings (15-20 wt.%). Slowly cooled samples contained higher amount of crystalline phases than quenched ones. Monazite is major phase for REs. Leach rates from the materials of major elements (Na, Al, Fe, P) are 10-5-10-7 g cm-2 d-1, RE elements - lower than 10-5 g cm-2 d-1.

  11. Luminescence studies on Dy3+ and Dy3+:Eu3+ co-doped boro-phosphate glasses for WLED applications

    Science.gov (United States)

    Vijayakumar, M.; Uma, V.; Arunkumar, S.; Marimuthu, K.

    2015-06-01

    Dy3+ and Dy3+:Eu3+ co-doped boro-phosphate glasses have been prepared and optically characterized using absorption, luminescence and decay measurements. The Nephelauxetic ratios (β), Bonding parameters (δ) and Judd-Ofelt (JO) intensity parameters Ωλ (λ = 2, 4 and 6) were calculated to study the nature of the environment around the RE3+ ions in the prepared glasses. The yellow to blue (Y/B) intensity ratio and the chromaticity color coordinates were calculated from the luminescence measurements. The lifetimes of the 4F9/2 excited level were measured using decay curves and is found to decrease in the Dy3+:Eu3+ co-doped glass due to the occurrence of resonant energy transfer between Dy3+-Eu3+ ions and the non-exponential decay rates have been fitted with Inokuti-Hirayama (IH) model. The decay curves are well fitted for S= 6 suggesting that the interaction between active ions for the energy transfer is of dipole-dipole nature.

  12. Influence of silver nanoparticles on the spectroscopic properties of Sm{sup 3+} doped boro-phosphate glasses

    Energy Technology Data Exchange (ETDEWEB)

    Suthanthirakumar, P.; Marimuthu, K., E-mail: emari-ram2000@yahoo.com [Department of Physics, Gandhigram Rural University, Gandhigram - 624 302 (India)

    2016-05-23

    The Sm{sup 3+} doped novel boro-phosphate glasses containing silver nanoparticles (NPs) (SmBPxA) have been prepared following the melt quenching technique and their structural and spectroscopic behavior were studied through HR-TEM, optical absorption and photoluminescence spectral measurements. The TEM analysis validates the existence of Ag NPs with an average diameter of ~8 nm. The Surface plasmon resonance (SPR) band of silver NPs was found at around 600 nm from the absorption spectrum of the Sm{sup 3+} ions free glass sample. The optical band gap energy (E{sub opt}) corresponding to the direct and indirect allowed transitions and the Urbach energy (ΔE) values were determined from the absorption spectral measurements. The luminescence intensity is found to get enhance when the Ag NPs were embedded along with the Sm{sup 3+} ions in the prepared glasses due to the local electric field effect around the rare earth (RE) ion site produced by the SPR of Ag NPs.

  13. Phosphate-induced metal stabilization: Use of apatite and bone char for the removal of soluble radionuclides in authentic and simulated DOE groundwater

    International Nuclear Information System (INIS)

    Bostick, W.D.; Jarabek, R.J.; Conca, J.L.

    1999-01-01

    The apatite group of minerals is a family of calcium phosphate phases. Apatite is the principal component of bone tissue, and it also occurs naturally as mineral deposits in the geosphere. Bone char is calcined (coked) animal bone, containing activated carbon as well as calcium phosphate mineral phases. Apatite IItrademark is a more reactive form of apatite, supplied by UFA Ventures, Inc., at a cost of approximately 1/4 that of commercial bone char. Apatite is shown to be effective for the removal of select heavy metal impurities in groundwater. Previous investigations have demonstrated that apatite is an effective medium for the stabilization of soluble lead, cadmium, and zinc from mine waste leachate by the formation of highly insoluble precipitate phases. The performance of bone char and apatite II are compared with other candidate sorption media (including granular activated carbon and anion exchange resin) for the removal of soluble uranyl ion in synthetic DOE Site groundwater supplemented with varying levels of interfering nitrate ion. Apatite II has a greater affinity for U(VI), especially in the presence of nitrate ion, as evidenced by a larger value for the conditional distribution coefficient (Kd) in batch test experiments. Contact of uranyl nitrate solution with apatite II is shown to produce highly insoluble mineral phases of the autunite group (calcium uranyl phosphate hydrates). Apatite II is also demonstrated to be moderately effective for the removal of soluble radioactive isotopes of strontium, but not cesium, when these ions are supplemented into authentic DOE Site groundwater

  14. Applicability of iron phosphate glass medium for loading NaCl originated from seawater used for cooling the stricken power reactors

    International Nuclear Information System (INIS)

    Amamoto, Ippei; Kobayashi, Hidekazu; Yokozawa, Takuma; Yamashita, Teruo; Nagai, Takayuki; Kitamura, Naoto; Takebe, Hiromichi; Mitamura, Naoki; Tsuzuki, Tatsuya

    2013-01-01

    As the part of investigation for immobilization of the sludge as one of the radioactive wastes arising from the treatment of contaminated water at Fukushima Dai-ichi nuclear power plant, applicability of vitrification method has been evaluated as a candidate technique. The aim of this study is to evaluate the influence of NaCl as one of the main constituents of sludge, on glass formation and glass properties. Two kinds of iron phosphate glass (IPG) media in the xFe 2 O 3 -(100-x)P 2 O 5 , with x=30 and 35 (mol%) were chosen and the glass formation, structure and properties including density, coefficient of thermal expansion, glass transition temperature, onset crystallization temperature and chemical durability of NaCl-loaded IPG were studied. The results are summarized as follows. Sodium chloride, NaCl could be loaded into IPG medium as Na 2 O and Cl contents and their loading ratio could be up to 19 and 15 mol%, respectively. Majority of Cl content of raw material NaCl was thought to be volatilized during glass melting. Loading NaCl into IPG induces to de-polymerize glass network of phosphate chains, leads to decrease both glass transition and onset crystallization temperatures, and to increase coefficient of thermal expansion. NaCl-loaded IPG indicated good chemical durability in case of using 35Fe 2 O 3 - 65P 2 O 5 medium. (authors)

  15. Microstructure and spectroscopic investigations of calcium zinc bismuth phosphate glass ceramics doped with manganese ions

    Science.gov (United States)

    Suneel Kumar, A.; Sambasiva Rao, M. V.; Chinna Ram, G.; Krishna Rao, D.

    2018-01-01

    Multi-component 10CaF2-20ZnO-(15 - x)Bi2O3-55P2O5:xMnO (0 ≤ x ≤ 2.5) glass ceramics were synthesised by melt quenching technique and heat treatment. The prepared glass ceramics were characterised by XRD, DTA, EDS and SEM. Spectroscopic studies such as optical absorption, EPR, FTIR and Raman were also carried out on these glass ceramics. The XRD and SEM studies have indicated that ceramic samples contain well defined and randomly distributed grains of different crystalline phases. The observed increase of enthalpy from DTA patterns up to 1 mol% of MnO indicates that the crystallisation starts initially from the surface of the material then gradually it is extended to the volume of the material and this influence is meagre at higher concentrations of MnO. The absorption spectra of manganese doped glass ceramics have exhibited two types of conventional bands; one due to Mn2+ ions and other due to Mn3+ ions. The EPR spectra of MnO doped glass ceramics showed a resonance signal around g2 = 2.023 with a six line hyperfine structure and another signal at about g1 = 4.314. The relative intensity and half-width of these two signals are observed to increase with the increase in the concentration of manganese ions up to 1 mol% beyond this concentration it is found to decrease. Such observation indicates the conversion of part of Mn2+ ions into Mn3+ ions in the glass ceramic matrix. The observed increase in the intensity of symmetrical structural units at the expense of asymmetrical structural units from the FTIR and Raman spectra at higher concentration of MnO indicating that Mn2+ ions occupy the network forming positions in the glass ceramic structure.

  16. Long-term conversion of 45S5 bioactive glass-ceramic microspheres in aqueous phosphate solution.

    Science.gov (United States)

    Fu, Hailuo; Rahaman, Mohamed N; Day, Delbert E; Huang, Wenhai

    2012-05-01

    The conversion of 45S5 glass and glass-ceramics to a hydroxyapatite (HA)-like material in vitro has been studied extensively, but only for short reaction times (typically glass-ceramic microspheres (designated 45S5c) in an aqueous phosphate solution. Microspheres of 45S5c (75-150 μm) were immersed for 10 years at room temperature (~25 °C) in K(2)HPO(4) solution with a concentration of 0.01 M or 1.0 M, and with a starting pH of 7.0 or 9.5. The reacted 45S5c microspheres and solutions were analyzed using structural and analytical techniques. Only 25-45 vol% of the 45S5c microspheres were converted to an HA-like material after the 10 year reaction. In solutions with a starting pH of 9.5, an increase in the K(2)HPO(4) concentration from 0.01 to 1.0 M resulted in a doubling of the volume of the microspheres converted to an HA-like material but had little effect on the composition of the HA-like product. In comparison, reaction of the 45S5c microspheres in the solution with a starting pH of 7.0 resulted in an HA-like product in the 0.01 M K(2)HPO(4) solution but a calcium pyrophosphate product, Ca(10)K(4)(P(2)O(7))(6).9H(2)O, in the 1.0 M solution. The consequences of these results for the long-term use of 45S5 glass-ceramics in biomedical applications are discussed.

  17. Molybdenum modified phosphate glasses studied by 31P MAS NMR and Raman spectroscopy.

    Science.gov (United States)

    Szumera, Magdalena

    2015-02-25

    Glasses have been synthesized in the system P2O5-SiO2-K2O-MgO-CaO modified by addition of MoO3. Glasses were prepared by conventional fusion method from 40 g batches. The influence of Mo-cations on the analysed glass structure was investigated by means of Raman and (31)P MAS-NMR techniques. It has been found that molybdate units can form Mo[MoO4/MoO6]-O-P and/or Mo[MoO4/MoO6]-O-Si bonds with non-bridging oxygens atoms of Q2 methaphosphate units, resulting in the transformation of chain methaphosphate structure into pyrophosphate and finally into orthophosphate structure. It has been also found that increasing amount of MoO3 in the structure of investigated glasses causes their gradual depolymerization and molybdenum ions in the analysed glass matrix act as modifying cations. Copyright © 2014 Elsevier B.V. All rights reserved.

  18. Effects of titanium nanoparticles on self-cleaning and structural features of zinc-magnesium-phosphate glass

    Energy Technology Data Exchange (ETDEWEB)

    Ismail, S.F.; Sahar, M.R., E-mail: mrahim057@gmail.com; Ghoshal, S.K.

    2016-02-15

    Graphical abstract: Water contact angle for sample S2, S3, S4 and S5. The water contact angle increased with increased the titanium NPs content (mol%). - Highlights: • ZnO–MgO–P{sub 2}O{sub 5} embedded TiO{sub 2} NPs prepared by conventional melt-quenching method. • The amorphous nature is confirmed by X-ray diffraction spectroscopy. • The structural characteristics of glasses is investigated using FTIR and Raman. • Wettability of the glasses surface by water contact angle. - Abstract: The loss of glass transparency on surface pollutants contamination unless inhibited not only causes vision obscurity but also responsible for major aesthetic damages of cultural heritage. It is due to the sticking of fine dirt particles on wetting layers, a complex process with several possible ramifications still to be clarified. We report the influence of titanium dioxide or titania (TiO{sub 2}) nanoparticles (NPs) on the structural and self-cleaning properties of zinc–magnesium–phosphate glasses. Following melt-quenching method glass samples of optimized composition (42 − x)P{sub 2}O{sub 5}–8MgO–50ZnO–xTiO{sub 2} with x = 0, 1, 2, 3 and 4 mol% are prepared. XRD patterns verified their amorphous nature and TEM images revealed the nucleation of TiO{sub 2} NPs of average diameter ≈4.05 ± 0.01 nm. Fourier transform infrared (FTIR) spectra displayed four absorption band centred at 1618–3438 cm{sup −1}, 902– 931 cm{sup −1}, 757–762 cm{sup −1} and 531–560 cm{sup −1}. Raman spectra exhibited four peaks each accompanied by a blue-shift. Water contact angle is found to increase with the increase of titanium NPs concentration into the amorphous matrix. This knowledge can be used to set up strategies and selective treatments to preventing glass transparency loss via the modification of self-cleaning attributes.

  19. Development, characterisation and biocompatibility testing of a cobalt-containing titanium phosphate-based glass for engineering of vascularized hard tissues

    Energy Technology Data Exchange (ETDEWEB)

    Lee, In-Ho [Department of Nanobiomedical Science and WCU Research Center of Nanobiomedical Science, Dankook University, Chungnam 330-714 (Korea, Republic of); Yu, Hye-sun [Department of Nanobiomedical Science and WCU Research Center of Nanobiomedical Science, Dankook University, Chungnam 330-714 (Korea, Republic of); Department of Biochemical Engineering, University College London, Torrington Place, London, WC1E 7JE (United Kingdom); Lakhkar, Nilay J. [Division of Biomaterials and Tissue Engineering, Eastman Dental Institute, University College London, 256 Gray' s Inn Road, London WC1X 8LD (United Kingdom); Kim, Hae-Won [Department of Nanobiomedical Science and WCU Research Center of Nanobiomedical Science, Dankook University, Chungnam 330-714 (Korea, Republic of); Institute of Tissue Regeneration Engineering (ITREN), Dankook University, Cheonan 330-714 (Korea, Republic of); Department of Biomaterials Science, College of Dentistry, Dankook University, Cheonan 330-714 (Korea, Republic of); Gong, Myoung-Seon [Department of Nanobiomedical Science and WCU Research Center of Nanobiomedical Science, Dankook University, Chungnam 330-714 (Korea, Republic of); Institute of Tissue Regeneration Engineering (ITREN), Dankook University, Cheonan 330-714 (Korea, Republic of); Knowles, Jonathan C. [Department of Nanobiomedical Science and WCU Research Center of Nanobiomedical Science, Dankook University, Chungnam 330-714 (Korea, Republic of); Division of Biomaterials and Tissue Engineering, Eastman Dental Institute, University College London, 256 Gray' s Inn Road, London WC1X 8LD (United Kingdom); Wall, Ivan B., E-mail: i.wall@ucl.ac.uk [Department of Nanobiomedical Science and WCU Research Center of Nanobiomedical Science, Dankook University, Chungnam 330-714 (Korea, Republic of); Department of Biochemical Engineering, University College London, Torrington Place, London, WC1E 7JE (United Kingdom)

    2013-05-01

    There is a continuing need to develop scaffold materials that can promote vascularisation throughout the tissue engineered construct. This study investigated the effect of cobalt oxide (CoO) doped into titanium phosphate glasses on material properties, biocompatibility and vascular endothelial growth factor (VEGF) secretion by osteoblastic MG63 cells. Glasses composed of (P{sub 2}O{sub 5}){sub 45}(Na{sub 2}O){sub 20}(TiO{sub 2}){sub 05}(CaO){sub 30−x}(CoO){sub x}(x = 0, 5, 10, and 15 mol%) were fabricated and the effect of Co on physicochemical properties including density, glass transition temperature (T{sub g}), degradation rate, ion release, and pH changes was assessed. The results showed that incorporation of CoO into the glass system produced an increase in density with little change in T{sub g}. It was then confirmed that the pH did not change significantly when CoO was incorporated in the glass, and stayed constant at around 6.5–7.0 throughout the dissolution study period of 336 h. Ion release results followed a specific pattern with increasing amounts of CoO. In general, although incorporation of CoO into a titanium phosphate glass increased its density, other bulk and surface properties of the glass did not show any significant changes. Cell culture studies performed using MG63 cells over a 7-day period indicated that the glasses provide a stable surface for cell attachment and are biocompatible. Furthermore, VEGF secretion was significantly enhanced on all glasses compared with standard tissue culture plastic and Co doping enhanced this effect further. In conclusion, the developed Co-doped glasses are stable and biocompatible and thus offer enhanced potential for engineering vascularized tissue. - Highlights: ► Phosphate-based glasses can be successfully doped with cobalt oxide. ► The resulting glass is highly stable with low degradation rate. ► Co-doped glasses are biocompatible but do not favour cell proliferation. ► Osteoblastic MG63 cells

  20. Optical spectroscopy, 1.06μm emission properties of Nd3+-doped phosphate based glasses.

    Science.gov (United States)

    Sk Nayab, Rasool; T, Sasikala; A, Mohan Babu; L, Rama Moorthy; C K, Jayasankar

    2017-06-05

    Neodymium doped phosphate based glasses with composition of (P 2 O 5 +K 2 O+Al 2 O 3 +CaF 2 ) were prepared. The samples were analysed through differential thermal analysis (DTA), Fourier transform infrared (FTIR), absorption, emission and decay measurements. Judd-Ofelt parameters (Ω λ ) have been determined from the spectral intensities of absorption bands in order to calculate the radiative parameters like radiative transition probabilities (A R ), radiative lifetime (τ R ) and branching ratios (β R ) for the 4 F 3/2 → 4 I 11/2 laser transition of Nd 3+ ion. The effective emission bandwidths (Δλ eff ), experimental branching ratios (β exp ) and stimulated emission cross-sections (σ e ) have been determined from the emission spectrum. The decay curves of the 4 F 3/2 level exhibited almost single exponential nature for all the Nd 3+ ion concentrations. Copyright © 2017 Elsevier B.V. All rights reserved.

  1. A novel disk-type X-ray area imaging detector using radiophotoluminescence in silver-activated phosphate glass

    International Nuclear Information System (INIS)

    Kurobori, Toshio; Nakamura, Shoichi

    2012-01-01

    We report a novel two- and three-dimensional (2-D, 3-D) imaging detector based on the radiophotoluminescence (RPL) phenomenon in silver-activated phosphate glass (PG:Ag) and evaluate its dosimetric characteristics. A compact disk-type PG:Ag detector with a diameter of 80 mm was rotated at a rate of 400 rpm to read out the accumulated dose information and then remove the images for reuse. After X-ray exposure, three RPL dosimeter processes, i.e., preheating, reading, and erasing, were carried out with only a UV laser at 375 nm by adjusting the stepwise output levels. The 3-D images and dose distributions were rapidly reconstructed with a high spatial resolution of 1 μm and a sensitivity of 1 mGy.

  2. SEALING ABILITY OF MINERAL TRIOXIDE AGGREGATE, CALCIUM PHOSPHATE CEMENT, AND GLASS IONOMER CEMENT IN THE REPAIR OF FURCATION PERFORATIONS

    Directory of Open Access Journals (Sweden)

    Prabath Singh

    2013-01-01

    Full Text Available Objectives: The purpose of this study was to evaluate the in vitro sealing ability of three repair materials. Mineral trioxide aggregate (MTA; Group A, calcium phosphate cement (CPC; Group B, and light cured glass ionomer cement (GIC; Group C when used to repair the perforation created in the pulpal floor of fifty extracted human permanent molars. Materials and methods: Preparation of access openings and furcation perforations were done, and the teeth divided into five experimental groups (A, B, C including two controls (D, E with ten samples in each group randomly. Following the repair procedure, the pulp chambers and access openings were filled with composite resin and immersed in 2% methylene blue solution for 48 hours. The teeth were sectioned longitudinally and the linear dye penetration measured under a stereo­microscope. Results: The comparison of the linear length of micro-leakage (mm among the experimental groups revealed no significant difference (p = 0.332. On calculating the percentage of depth of leakage to the total length of the perforation, it was observed that the mean leakage was 35.5% in Group A, 53.6% in Group B and the highest, 87.5% in Group C. The mean of leakage percentage was statistically significant by Kruskal-Wallis test (p = 0.003. The results indicated that the dye penetration used as furcation perforation repair material was least with mineral trioxide aggregate. Comparing the depth of penetration of dye, 50% of the Group A samples showed less than 25% of depth penetration. While 40% of Group B cases had more than 50% dye penetration. In our study, all Group C teeth had ≥ 50% dye penetration. Conclusions: The present study indicated that GIC had the greatest dye penetration followed by CPC and MTA. Mineral trioxide aggregate and calcium phosphate cement had comparatively better sealing ability than glass ionomer cement.

  3. Peculiarities of the diffusion of silver and sodium ions in phosphate glasses with a high content of sodium oxide

    International Nuclear Information System (INIS)

    Syutkin, V.M.; Tolkatchev, V.A.

    1996-01-01

    The phosphate glasses with a high content of alkali metal ions are good ionic conductors. Despite active studies, the mechanism of ion diffusion is not so far clear. The present work discusses the characteristics of ion diffusion in phosphate glasses with a high content of sodium oxide. An effective method to study ion transport is the investigation of relaxation processes the kinetics of which depends on ion diffusion. We use the data for two types of relaxation processes the kinetics of which is determined by ion diffusion. This is the conductivity relaxation due to sodium (host) ions and the decay of radiation-induced centers controlled by silver (guest) ion diffusion. Both of the processes being actually the first-order processes display a nonexponential kinetic behavior. The relaxation law can be interpreted either as the inherently nonexponential function or as the weighted sum of exponential decay functions with a distribution of relaxation times. It has been demonstrated that on the molecular level the relaxation function should be interpreted in the frame of the scheme of parallel first-order processes. This fact allows one to formulate a number of features of ion diffusion: (i) the mean square displacement of ions does not exceed several angstrom when transport becomes non-dispersive; (ii) the diffusion coefficient of ions is the function of coordinates. In this case, a characteristic distance at which D(r) noticeably varies is no less than a hundred of angstrom; (iii) the instantaneous concentration of mobile ions is well below the overall concentration ions

  4. Mechanical properties and ion release from bioactive restorative composites containing glass fillers and calcium phosphate nano-structured particles.

    Science.gov (United States)

    Chiari, Marina D S; Rodrigues, Marcela C; Xavier, Tathy A; de Souza, Eugen M N; Arana-Chavez, Victor E; Braga, Roberto R

    2015-06-01

    To evaluate the effect of the replacement of barium glass by dicalcium phosphate dihydrate (DCPD) particles on the mechanical properties and degree of conversion (DC) of composites. Additionally, calcium and hydrogen phosphate (HPO4(2-)) release were followed for 28 days. Nine composites containing equal parts (in mols) of BisGMA and TEGDMA and 40, 50 or 60 vol% of total filler were manipulated. Filler phase was constituted by silanated barium glass and 0%, 10% or 20% of DCPD particles. DC was determined by near-FTIR. Biaxial flexural strength (BFS) and modulus (E) were tested using the "piston on three balls" method, while fracture toughness (KIc) used the "single edge notched beam" method. Specimens were tested after 24h and 28 days in water. Ion release was determined using inductively coupled plasma optical emission spectrometry (ICP-OES). Data were analyzed by ANOVA/Tukey (DC and ion release) or Kruskal-Wallis/Mann-Whitney (mechanical properties; alpha: 5%). DC was not affected by DCPD. The presence of DCPD reduced BFS for both storage times, while differences in E became evident after 28 days. After 24h, KIc increased with the addition of DCPD; after 28 days, however, KIc decreased only for DCPD-containing composites. Calcium release was similar for both DCPD contents and remained fairly constant during the 28-day period. Overall, HPO4(2-) release was higher at 7 days and did not decrease after 14 days. The composite with the highest filler level and 10% DCPD represented the best compromise between mechanical properties after aging in water and ion release. Copyright © 2015 Academy of Dental Materials. Published by Elsevier Ltd. All rights reserved.

  5. Effect of gamma irradiation on optical properties of Ce 3+ - doped phosphate and silicate scintillating glasses

    Czech Academy of Sciences Publication Activity Database

    Baccaro, S.; Cecilia, A.; Chen, B.; Mareš, Jiří A.; Mihóková, Eva; Nikl, Martin; Polato, P.; Zanella, G.; Zannoni, R.

    2002-01-01

    Roč. 63, - (2002), s. 231-234 ISSN 0969-806X R&D Projects: GA MŠk ME 519 Institutional research plan: CEZ:AV0Z1010914 Keywords : glass scintillator * radiation hardness * colour centres Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 0.738, year: 2002

  6. EUROPIUM ION INFLUENCE ON THE FORMATION OF Ag-NANOPARTICLES IN FLUORINE PHOSPHATE GLASSES

    Directory of Open Access Journals (Sweden)

    R. O. Pysh'ev

    2015-05-01

    Full Text Available The paper deals with research of formation characteristics of silver nanoparticles in fluorophosphate glasses 0.25 Na2O - 0.5 P2O5 - 0.10 Ga2O3 - 0.075 AlF3 - 0.025 NaF - 0.05 ZnF2 doped with EuF3 (0.8 and 4 wt.% and without them. The synthesis was carried out in closed glassy carbon crucibles in argon atmosphere. Nanoparticles were formed after a low temperature process of Ag+ → Na+ ion-exchange (320 °C and subsequent heat treatment. It was shown that in the initial glasses doped with EuF3, rare earth ions exist in two valence forms (Eu2+ and Eu3+ in dynamic equilibrium and the concentration of Eu2+ increases proportionally to the total concentration of fluoride. It was shown that sizes of molecular clusters or metal nanoparticles depend on the concentration of europium fluoride and duration of ion exchange. The metallic Ag-nanoparticles sizes were defined for different times of heat treatment and ion exchange. The possibility of the stimulating growth of nanoparticles through the introduction of additional EuF3 in the glass was proved. The possibility of obtaining nanoparticles without the heat treatment in glasses with a high concentration of EuF3 was shown. Chemical mechanism for the formation of Ag-nanoparticles during the ion exchange was suggested.

  7. On the optical band gap in certain ternary phosphate and TeO2 based glasses

    Czech Academy of Sciences Publication Activity Database

    Tichá, H.; Tichý, Ladislav

    2011-01-01

    Roč. 5, č. 12 (2011), s. 1277-1281 ISSN 1842-6573 Institutional research plan: CEZ:AV0Z40500505 Keywords : optical band gap * heavy metal oxide glasses Subject RIV: CA - Inorganic Chemistry Impact factor: 0.304, year: 2011 http://oam-rc.inoe.ro/index.php?option=magazine&op=view&idu=1737&catid=69

  8. Electrospinning of calcium phosphate-poly(D,L-lactic acid nanofibers for sustained release of water-soluble drug and fast mineralization

    Directory of Open Access Journals (Sweden)

    Fu QW

    2016-10-01

    Full Text Available Qi-Wei Fu,1,* Yun-Peng Zi,1,* Wei Xu,1 Rong Zhou,1 Zhu-Yun Cai,1 Wei-Jie Zheng,1 Feng Chen,2 Qi-Rong Qian1 1Department of Orthopedics, Changzheng Hospital, Second Military Medical University, 2State Key Laboratory of High Performance Ceramics and Superfine Microstructure, Shanghai Institute of Ceramics, Chinese Academy of Sciences, Shanghai, People’s Republic of China *These authors contributed equally to this work Abstract: Calcium phosphate-based biomaterials have been well studied in biomedical fields due to their outstanding chemical and biological properties which are similar to the inorganic constituents in bone tissue. In this study, amorphous calcium phosphate (ACP nanoparticles were prepared by a precipitation method, and used for preparation of ACP-poly(D,L-lactic acid (ACP-PLA nanofibers and water-soluble drug-containing ACP-PLA nanofibers by electrospinning. Promoting the encapsulation efficiency of water-soluble drugs in electrospun hydrophobic polymer nanofibers is a common problem due to the incompatibility between the water-soluble drug molecules and hydrophobic polymers solution. Herein, we used a native biomolecule of lecithin as a biocompatible surfactant to overcome this problem, and successfully prepared water-soluble drug-containing ACP-PLA nanofibers. The lecithin and ACP nanoparticles played important roles in stabilizing water-soluble drug in the electrospinning composite solution. The electrospun drug-containing ACP-PLA nanofibers exhibited fast mineralization in simulated body fluid. The ACP nanoparticles played the key role of seeds in the process of mineralization. Furthermore, the drug-containing ACP-PLA nanofibers exhibited sustained drug release which simultaneously occurred with the in situ mineralization in simulated body fluid. The osteoblast-like (MG63 cells with spreading filopodia were well observed on the as-prepared nanofibrous mats after culturing for 24 hours, indicating a high cytocompatibility. Due

  9. Solubility of crystalline organic compounds in high and low molecular weight amorphous matrices above and below the glass transition by zero enthalpy extrapolation.

    Science.gov (United States)

    Amharar, Youness; Curtin, Vincent; Gallagher, Kieran H; Healy, Anne Marie

    2014-09-10

    Pharmaceutical applications which require knowledge of the solubility of a crystalline compound in an amorphous matrix are abundant in the literature. Several methods that allow the determination of such data have been reported, but so far have only been applicable to amorphous polymers above the glass transition of the resulting composites. The current work presents, for the first time, a reliable method for the determination of the solubility of crystalline pharmaceutical compounds in high and low molecular weight amorphous matrices at the glass transition and at room temperature (i.e. below the glass transition temperature), respectively. The solubilities of mannitol and indomethacin in polyvinyl pyrrolidone (PVP) K15 and PVP K25, respectively were measured at different temperatures. Mixtures of undissolved crystalline solute and saturated amorphous phase were obtained by annealing at a given temperature. The solubility at this temperature was then obtained by measuring the melting enthalpy of the crystalline phase, plotting it as a function of composition and extrapolating to zero enthalpy. This new method yielded results in accordance with the predictions reported in the literature. The method was also adapted for the measurement of the solubility of crystalline low molecular weight excipients in amorphous active pharmaceutical ingredients (APIs). The solubility of mannitol, glutaric acid and adipic acid in both indomethacin and sulfadimidine was experimentally determined and successfully compared with the difference between their respective calculated Hildebrand solubility parameters. As expected from the calculations, the dicarboxylic acids exhibited a high solubility in both amorphous indomethacin and sulfadimidine, whereas mannitol was almost insoluble in the same amorphous phases at room temperature. This work constitutes the first report of the methodology for determining an experimentally measured solubility for a low molecular weight crystalline solute

  10. Structure and properties of barium tin boro-phosphate glass systems with very low photoelastic constant

    Science.gov (United States)

    Itadani, M.; Tricot, G.; Doumert, B.; Takebe, H.; Saitoh, A.

    2017-08-01

    Glasses in the BaO-SnO-P2O5-B2O3 system were prepared and evaluated in order to formulate preform glasses suitable for the fabrication of fiber cores with a very low photoelastic constant. A first glass system (I: xBaO-(60-x)SnO-40P2O5) was designed with a constant P2O5 content and various BaO contents (0-40 mol. %). Introduction of 3 mol. % of B2O3 to enhance the glass stability leads to the second glass system (II: x'BaO-(57-x')SnO-40P2O5-3B2O3) with 33-38 mol. % BaO. The structure of both systems was investigated by 1D/2D magic-angle spinning nuclear magnetic resonance, Raman, and Fourier transform infrared spectroscopic techniques. 31P NMR showed the presence of Q2 and Q1 units in the first system and correlation 11B/31P NMR indicated that boron enters into the network as B(OP)4 structural units. The photoelastic constant was determined and the stability of the best formulations as well as their refractive index dispersion was established. The drawing temperature and isothermal heating time (without crystal precipitation) parameters were also accurately measured by using experimental time-temperature-transition. Considering that the refractive indices of the core and the cladding materials must match, detailed core and cladding compositions for a fiber enabling single-mode waveguide transmission were proposed.

  11. Characterization of radiative properties of Nd{sub 2}O{sub 3} doped phosphate and silicate glasses for solid state laser

    Energy Technology Data Exchange (ETDEWEB)

    Nandi, P., E-mail: pnandi@barc.gov.in; Shukla, R., E-mail: pnandi@barc.gov.in; Goswami, M., E-mail: pnandi@barc.gov.in [Glass and Advanced Materials Division, Bhabha Atomic Research Centre, Mumbai-400085 (India); Sudarsan, V. [Chemistry Division, Bhabha Atomic Research Centre, Trombay, Mumbai-400085 (India)

    2014-04-24

    Nd{sub 2}O{sub 3} doped calcium aluminium phosphate and calcium aluminium silicate glasses prepared to compare their absorption and emission properties. Radiative lifetime of the excited state {sup 4}F{sub 3/2} derived by Judd-Ofelt theory applied to the absorption spectra. Using the photoluminescence spectrometer the steady state emission and relaxation time from excited energy level recorded under green light excitation. Phosphate glass has higher emission cross-section, higher radiative lifetime but less quantum efficiency due to non-radiative quenching through hydroxyl ions compared to silicate glass for Nd{sup 3+}:{sup 4}F{sub 3/2}→{sup 4}I{sub 9/2} emission.

  12. Erbium-doped phosphate glass waveguide on silicon with 4.1 dB/cm gain at 1.535 µm

    Science.gov (United States)

    Yan, Y. C.; Faber, A. J.; de Waal, H.; Kik, P. G.; Polman, A.

    1997-11-01

    Erbium-doped multicomponent phosphate glass waveguides were deposited by rf sputtering techniques. The Er concentration was 5.3×1020cm-3. By pumping the waveguide at 980 nm with a power of ˜21 mW, a net optical gain of 4.1 dB at 1.535 μm was achieved. This high gain per unit length at low pump power could be achieved because the Er-Er cooperative upconversion interactions in this heavily Er-doped phosphate glass are very weak [the upconversion coefficient is (2.0±0.5)×10-18 cm3/s], presumably due to the homogeneous distribution of Er in the glass and due to the high optical mode confinement in the waveguide which leads to high pump power density at low pump power.

  13. Quantum efficiency of Yb{sup 3+}–ZnTe co-doped phosphate glass system

    Energy Technology Data Exchange (ETDEWEB)

    Falci, R.F.; Freitas, A.M.; Silva, G.H. [Laboratório de Espectroscopia de Materiais, Departamento de Física, ICE, Universidade Federal de Juiz de Fora, 36036-330, Juiz de Fora, MG (Brazil); Pinheiro, A.S. [Centro Federal de EducaçãoTecnológica Celso Suckow da Fonseca (CEFET/RJ) - Campus Petrópolis, CEP 25620-003, Petrópolis - RJ (Brazil); Dantas, N.O. [Laboratório de Novos Materiais Isolantes e Semicondutores (LNMIS), Instituto de Física da Universidade Federal de Uberlândia, CP 593, CEP 38400-902, Uberlândia, MG (Brazil); Anjos, V., E-mail: virgilio@fisica.ufjf.br [Laboratório de Espectroscopia de Materiais, Departamento de Física, ICE, Universidade Federal de Juiz de Fora, 36036-330, Juiz de Fora, MG (Brazil); Bell, M.J.V. [Laboratório de Espectroscopia de Materiais, Departamento de Física, ICE, Universidade Federal de Juiz de Fora, 36036-330, Juiz de Fora, MG (Brazil)

    2016-08-15

    The present paper deals with optical properties of a highly transparent phosphate glass co-doped with Yb{sup 3+} and ZnTe nanocrystals. The presence of ZnTe nanocrystals is due to a sequential melting–nucleation procedure evidenced by optical absorption and Atomic Force Microscopy. From the perspective of compositional variation of the dopants, photoluminescence and lifetime measurements were performed. As a result, it was demonstrated that the ZnTe nanocrystals increase the Yb{sup 3+} emission by a factor up to five, when the pumping wavelength is resonant with the ZnTe absorption. It was also verified that the ZnTe nanocrystals inhibit the self-trapping of the rare earth luminescence. As a consequence, the quantum efficiency of the {sup 5}F{sub 7/2}→{sup 5}F{sub 5/2} transitions of the Yb{sup 3+} is considerably increased. Finally, we have found that the glass thermal diffusivity is not sensitive to temperature variations comprising the interval from room temperature to cryogenic temperatures. This can be an important property when considering this material to future applications in high-power photonic devices.

  14. Effect of nanocrystallization on the electrical conduction of silver lithium phosphate glasses containing iron and vanadium

    Energy Technology Data Exchange (ETDEWEB)

    Hassaan, M. Y., E-mail: myhassaan@yahoo.com [Al-Azhar University, Physics Department, Faculty of Science (Egypt); El-Desoky, M. M. [Suez Canal University, Physics Department, Faculty of Science (Egypt); Masuda, H.; Kubuki, S. [Tokyo Metropolitan University, Department of Chemistry, Graduate School of Science and Engineering (Japan); Nishida, T. [Kinki University, Department of Biological and Environmental Chemistry, Faculty of Humanity-Oriented Science and Engineering (Japan)

    2012-03-15

    xLi{sub 2}O{center_dot}(20-x)Ag{sub 2}O{center_dot}20Fe{sub 2}O{sub 3}{center_dot}60P{sub 2}O{sub 5} glasses (x = 0, 5, 10, 15 and 20 mol%) and 5Ag{sub 2}O{center_dot}15Li{sub 2}O{center_dot}5V{sub 2}O{sub 5}{center_dot}15Fe{sub 2}O{sub 3}{center_dot}60P{sub 2}O{sub 5} glass were prepared by melt-quenching of the reagent mixture at 1000 Degree-Sign C. Glass transition temperature (T{sub g}) and crystallization temperature (T{sub c}) of these samples were determined by differential thermal analysis (DTA). It proved that T{sub g} increased with Li{sub 2}O content. XRD of as-quenched glasses confirmed their amorphous nature. XRD of samples heat treated for one hour at temperature near their T{sub c}, indicated nanocrystals precipitated in the glassy matrix with an average particle size of 35 nm. Moessbauer results revealed that the relative fraction of Fe{sup 2 + } was decreased with an increasing Li{sub 2}O content. The isomer shift values of Fe{sup 3 + } lie in a range of 0.38-0.45 mm s{sup - 1}, while those for Fe{sup 2 + } were 1.10-1.31 mm s{sup - 1}. Heat-treated sample of 5Ag{sub 2}O{center_dot}15Li{sub 2}O{center_dot}5V{sub 2}O{sub 5}{center_dot}15Fe{sub 2}O{sub 3}{center_dot}60P{sub 2}O{sub 5} glass exhibit an enhancement of the electrical conductivity by three orders of magnitude due to the 3d-electron (polaron) hopping from V{sup 4 + } to V{sup 5 + } in the 'vanadate glass' units.

  15. Synthesis and characterization of cerium containing iron phosphate based glass-ceramics

    Science.gov (United States)

    Deng, Yi; Liao, Qilong; Wang, Fu; Zhu, Hanzhen

    2018-02-01

    The structure and properties of xCeO2-(100-x)(40Fe2O3-60P2O5), where x = 0, 2, 4, 6 and 8 mol%, glass-ceramics prepared by melting and slow cooling method have been investigated by using X-ray diffraction (XRD), scanning electron microscope (SEM), Fourier transform infrared spectroscopy (FTIR), differential thermal analysis (DTA) and the Product Consistency Test (PCT). The results show that the 40Fe2O3-60P2O5 sample is homogeneously amorphous and the sample containing 2 mol% CeO2 has a small amount of FePO4 phase embedded. For the sample containing up to 4 mol% CeO2, monazite CePO4 and a small amount of FePO4 appear. Spectra analysis show that the structure networks of the glass-ceramics mainly consist of orthophosphate, along with pyrophosphate and a small amount of metaphosphate units. Moreover, the leaching rates of Fe and Ce are about 3.5 × 10-5 g m-2 d-1 and 5.0 × 10-5 g m-2 d-1 respectively after immersion in deionized water at 90 °C for 56 days, indicating their good chemical durability. The conclusions imply that the prepared method may be a promising process to immobilize nuclear waste into glass-ceramic matrix.

  16. Influence of samarium ions (Sm3+) on the optical properties of lithium zinc phosphate glasses

    Science.gov (United States)

    Shwetha, M.; Eraiah, B.

    2018-05-01

    New glass samples with composition xSm2O3-(15-x) Li2O-45ZnO-40P2O5, where x= 0, 0.1, 0.3 and 0.5 mol % are prepared by conventional melt-quenching method. X-ray Diffraction measurements were performed to confirm their amorphous nature. Densities of these glasses were measured by Archimedes method. Optical properties were studied using optical absorption spectra which was recorded at room temperature in the UV-Vis region. Electronic transitions specific to the rare earth ion were observed from the UV-Visible spectroscopy. Optical direct band gap and indirect band gap energies were measured and their values were found to be between 4.23-4.74 eV and 3.02-3.67 eV, respectively. Refractive index has been measured with respect to different concentrations of Sm2O3. Polaron radius, inter-nuclear distance, field strength, dielectric constant and polarizability of oxide ions have been calculated. Fluorescence spectroscopy measurements have been performed by excitation in the UV-Visible range, which resulted in the significant fluorescence peaks. The luminescence color of the glass system has been characterized using Commission International de l'Eclairage de France 1931 chromaticity diagram.

  17. Controlled copper ion release from phosphate-based glasses improves human umbilical vein endothelial cell survival in a reduced nutrient environment.

    Science.gov (United States)

    Stähli, Christoph; Muja, Naser; Nazhat, Showan N

    2013-02-01

    The success of tissue engineering is dependent on rapid scaffold vascularization after engraftment. Copper ions are well known to be angiogenic but exhibit cytotoxicity at elevated doses. The high sensitivity to copper concentration underlines the need of a controlled release mechanism. This study investigated the effect of copper ions released from phosphate-based glasses (PGs) on human umbilical vein endothelial cells (HUVECs) under standard growth conditions (SGC), as well as in a reduced nutrient environment (RNE) with decreased bovine serum and growth factor concentrations to approximate conditions in the core of large volume scaffolds where nutrient diffusion is limited. Initially, HUVECs were exposed to a range of CuCl(2) concentrations in order to identify an optimal response in terms of their metabolism, viability, and apoptotic activity. Under SGC, HUVEC metabolic activity and viability were reduced in a dose-dependent manner in the presence of 0.44-12 ppm Cu(2+). In contrast, HUVEC death induced by the RNE was delayed by an optimal dose of 4 ppm Cu(2+), which was associated with a down-regulation of apoptosis as evidenced by caspase-3/7 activity. Copper ion release from soluble PGs of the formulation 50P(2)O(5)-30CaO-(20-x)Na(2)O-xCuO [mol%] (x=0, 1, 5 and 10) demonstrated a controllable increase with CuO content. The presence of 4 ppm copper ions released from the 10% CuO PG composition reproduced the delay in HUVEC death in the RNE, suggesting the potential of these materials to extend survival of transplanted endothelial cells in large volume scaffolds.

  18. RHENIUM SOLUBILITY IN BOROSILICATE NUCLEAR WASTE GLASS IMPLICATIONS FOR THE PROCESSING AND IMMOBILIZATION OF TECHNETIUM-99 (AND SUPPORTING INFORMATION WITH GRAPHICAL ABSTRACT)

    Energy Technology Data Exchange (ETDEWEB)

    AA KRUGER; A GOEL; CP RODRIGUEZ; JS MCCLOY; MJ SCHWEIGER; WW LUKENS; JR, BJ RILEY; D KIM; M LIEZERS; P HRMA

    2012-08-13

    The immobilization of 99Tc in a suitable host matrix has proved a challenging task for researchers in the nuclear waste community around the world. At the Hanford site in Washington State in the U.S., the total amount of 99Tc in low-activity waste (LAW) is {approx} 1,300 kg and the current strategy is to immobilize the 99Tc in borosilicate glass with vitrification. In this context, the present article reports on the solubility and retention of rhenium, a nonradioactive surrogate for 99Tc, in a LAW sodium borosilicate glass. Due to the radioactive nature of technetium, rhenium was chosen as a simulant because of previously established similarities in ionic radii and other chemical aspects. The glasses containing target Re concentrations varying from 0 to10,000 ppm by mass were synthesized in vacuum-sealed quartz ampoules to minimize the loss of Re by volatilization during melting at 1000 DC. The rhenium was found to be present predominantly as Re7 + in all the glasses as observed by X-ray absorption near-edge structure (XANES). The solubility of Re in borosilicate glasses was determined to be {approx}3,000 ppm (by mass) using inductively coupled plasma-optical emission spectroscopy (ICP-OES). At higher rhenium concentrations, some additional material was retained in the glasses in the form of alkali perrhenate crystalline inclusions detected by X-ray diffraction (XRD) and laser ablation-ICP mass spectrometry (LA-ICP-MS). Assuming justifiably substantial similarities between Re7 + and Tc 7+ behavior in this glass system, these results implied that the processing and immobilization of 99Tc from radioactive wastes should not be limited by the solubility of 99Tc in borosilicate LAW glasses.

  19. The structure of phosphate and borosilicate glasses and their structural evolution at high temperatures as studied with solid state NMR spectroscopy: Phase separation, crystallisation and dynamic species exchange

    International Nuclear Information System (INIS)

    Wegner, S.; Van Wullen, L.; Tricot, G.; Tricot, G.

    2010-01-01

    In this contribution we present an in-depth study of the network structure of different phosphate based and borosilicate glasses and its evolution at high temperatures. Employing a range of advanced solid state NMR methodologies, complemented by the results of XPS, the structural motifs on short and intermediate length scales are identified. For the phosphate based glasses, at temperatures above the glass transition temperature Tg, structural relaxation processes and the devitrification of the glasses were monitored in situ employing MAS NMR spectroscopy and X-ray diffraction. Dynamic species exchange involving rapid P-O-P and P-O-Al bond breaking and reforming was observed employing in situ 27 Al and 31 P MAS NMR spectroscopy and could be linked to viscous flow. For the borosilicate glasses, an atomic scale investigation of the phase separation processes was possible in a combined effort of ex situ NMR studies on glass samples with different thermal histories and in situ NMR studies using high temperature MAS NMR spectroscopy including 11 B MAS, 29 Si MAS and in situ 29 Si{ 11 B} REAPDOR NMR spectroscopy. (authors)

  20. Effect of the addition of Na2O on the thermal properties and chemical durability of glasses of iron and uranium phosphates

    International Nuclear Information System (INIS)

    Arboleda Zuluaga, P.A; Rodriguez, D.S; Gonzalez Oliver, C; Rincon Lopez, J.M; Soldera, F

    2012-01-01

    A series of glass compositions including (54,6-73,5P 2 O 5 .14-22Fe 2 O 3.x Na 2 O.2,8-4,25 UO 2 ) %mol. x=0-28,4 were studied in function of sodium oxide content for the thermal properties and chemical durability. By means differential dilatometer measurements was possible establish the variation of Tg, and α Tsoft and analysis of the kinetics of sintering by means of High Temperature Microscopy (MAT) and dilatometric data of pressed pellets. The presence of modifier oxides in the structure of iron phosphate glasses causes slightly onset sintering anticipation in almost 25 o C The chemical durability was estimated performing the named Product Consistency Test (PCT-B) focused on determining the resistance of glasses for nuclear wastes. These glasses exhibit good chemical durability but it is significant impaired by the addition of x≥6wt%Na 2 O. It is aimed to achieve more stable compositions and get glass matrixes able to contain more uranium oxides allowing evaluating the potential application of these iron phosphate glasses for special, industrial and nuclear waste immobilization

  1. Study on the water durability of zinc boro-phosphate glasses doped with MgO, Fe2O3, and TiO2

    Science.gov (United States)

    Hwang, Moon Kyung; Ryu, Bong Ki

    2016-07-01

    The water durability of zinc boro-phosphate (PZB) glasses with the composition 60P2O5-20ZnO-20B2O3- xMeO ( x = 0, 2, 4, 6 and MeO = MgO, Fe2O3, or TiO2) (mol%) was measured, and PZB glass was studied in terms of its thermal properties, density, and FTIR characteristics. The surface conditions and corrosion byproducts were analyzed using scanning electron microscopy. When MgO, Fe2O3, and TiO2 were doped into the PZB glass, Q2 was decreased and Q1 was increased in the phosphate structure, while the number of BO4 structures increased with increasing MeO content. The density of the PZB glass was increased by the addition of Fe2O3 and TiO2, while the glass transition temperature ( T g ) and dilatometric softening temperature ( T d ) were increased when additional MgO, Fe2O3, and TiO2 were added. From the weight loss analysis (95 ◦ C, 96 h), TiO2 doped glass showed the lowest weight loss (1.70 × 10 -3 g/cm2) while MgO doped glass showed the highest value (2.44 × 10 -3 g/cm2), compared with PZB glass (3.07 × 10 -3 g/cm2). These results were discussed in terms of the Me n+ ions in the glass structure, and their different coordination numbers and bonding strengths.

  2. Absorption Spectroscopy Analysis of Calcium-Phosphate Glasses Highly Doped with Monovalent Copper.

    Science.gov (United States)

    Jiménez, José A

    2016-06-03

    CaO-P2 O5 glasses with high concentrations of monovalent copper ions were prepared by a simple melt-quench method through CuO and SnO co-doping. Spectroscopic characterization was carried out by optical absorption with the aim of analyzing the effects of Cu(+) ions on the optical band-gap energies, which were estimated on the basis of indirect-allowed transitions. The copper(I) content is estimated in the CuO/SnO-containing glasses after the assessment of the concentration dependence of Cu(2+) absorption in the visible region for CuO singly doped glasses. An exponential dependence of the change in optical band gaps (relative to the host) with Cu(+) concentration is inferred up to about 10 mol %. However, the entire range is divided into two distinct linear regions that are characterized by different rates of change with respect to concentration: 1) below 5 mol %, where the linear dependence presents a relatively high magnitude of the slope; and 2) from 5-10 mol %, where a lower magnitude of the slope is manifested. With increasing concentration, the mean Cu(+) -Cu(+) interionic distance decreases, thereby decreasing the sensitivity of monovalent copper for light absorption. The decrease in optical band-gap energies is ultimately shown to follow a linear dependence with the interionic distance, suggesting the potential of the approach to gauge the concentration of monovalent copper straightforwardly in amorphous hosts. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  3. Optical and electrical characterizations of multifunctional silver phosphate glass and polymer-based optical fibers.

    Science.gov (United States)

    Rioux, Maxime; Ledemi, Yannick; Morency, Steeve; de Lima Filho, Elton Soares; Messaddeq, Younès

    2017-03-03

    In recent years, the fabrication of multifunctional fibers has expanded for multiple applications that require the transmission of both light and electricity. Fibers featuring these two properties are usually composed either of a single material that supports the different characteristics or of a combination of different materials. In this work, we fabricated (i) novel single-core step-index optical fibers made of electrically conductive AgI-AgPO 3 -WO 3 glass and (ii) novel multimaterial fibers with different designs made of AgI-AgPO 3 -WO 3 glass and optically transparent polycarbonate and poly (methyl methacrylate) polymers. The multifunctional fibers produced show light transmission over a wide range of wavelengths from 500 to 1000 nm for the single-core fibers and from 400 to 1000 nm for the multimaterial fibers. Furthermore, these fibers showed excellent electrical conductivity with values ranging between 10 -3 and 10 -1  S·cm -1 at room temperature within the range of AC frequencies from 1 Hz to 1 MHz. Multimodal taper-tipped fibre microprobes were then fabricated and were characterized. This advanced design could provide promising tools for in vivo electrophysiological experiments that require light delivery through an optical core in addition to neuronal activity recording.

  4. Competitive immobilization of Pb in an aqueous ternary-metals system by soluble phosphates with varying pH.

    Science.gov (United States)

    Zhang, Zhuo; Ren, Jie; Wang, Mei; Song, Xinlai; Zhang, Chao; Chen, Jiayu; Li, Fasheng; Guo, Guanlin

    2016-09-01

    Chemical immobilization by phosphates has been widely and successfully applied to treat Pb in wastewater and contaminated soils. Pb in wastewaters and soils, however, always coexists with other heavy metals and their competitive reactions with phosphates have not been quantitatively and systematically studied. In this approach, immobilization of Pb, Zn, and Cd by mono-, di-, and tripotassium phosphate (KH2PO4, K2HPO4, and K3PO4) was observed in the single- and ternary-metals solutions. The immobilization rates of the three metals were determined by the residual concentration. The mineral composition and structure of the precipitates were characterized by powder X-ray diffraction (XRD) analysis and scanning electron microscopy (SEM). The results indicated that competitive reaction occurred in Pb-Zn-Cd ternary system, with immobilization rates decrease of system. The reaction of Pb with three phosphates exhibited intense competitiveness and the phosphates had a stronger affinity for Pb when Cl(-) was added. Pb-phosphate minerals formed by KH2PO4 with the better crystalline characteristics and largest size were very stable with a low dissolution rate (system. Copyright © 2016 Elsevier Ltd. All rights reserved.

  5. Studies in the preparation of /sup 32/P labelled compounds from high grade rock phosphate with high fluorine content. [Water soluble P/sub 2/O/sub 5/, acidulation, curing

    Energy Technology Data Exchange (ETDEWEB)

    Murthy, T S; Cherian, S; Shivarudrappa, V; Subramanian, T K; Achari, P S [Bhabha Atomic Research Centre, Bombay (India). Primary Isotopes Section

    1981-01-01

    The labelled phosphate to be used for crop evaluation studies should have characteristics exactly similar to the industrial product employed in agriculture. For the preparation of /sup 32/P labelled compound from rock phosphate with high fluorine content, a number of parameters have been studied like particle size of the rock, temperature and amount of acid required, the curing time, etc. Because of the high reaction temperature, the curing time is reduced to experimental limits compared to the commercial product. This paper describes a method for the preparation of such a labelled phosphate and this yields a product with about 95% of the phosphate in the water soluble form.

  6. In-situ polymerisation of fully bioresorbable polycaprolactone/phosphate glass fibre composites: In vitro degradation and mechanical properties.

    Science.gov (United States)

    Chen, Menghao; Parsons, Andrew J; Felfel, Reda M; Rudd, Christopher D; Irvine, Derek J; Ahmed, Ifty

    2016-06-01

    Fully bioresorbable composites have been investigated in order to replace metal implant plates used for hard tissue repair. Retention of the composite mechanical properties within a physiological environment has been shown to be significantly affected due to loss of the integrity of the fibre/matrix interface. This study investigated phosphate based glass fibre (PGF) reinforced polycaprolactone (PCL) composites with 20%, 35% and 50% fibre volume fractions (Vf) manufactured via an in-situ polymerisation (ISP) process and a conventional laminate stacking (LS) followed by compression moulding. Reinforcing efficiency between the LS and ISP manufacturing process was compared, and the ISP composites revealed significant improvements in mechanical properties when compared to LS composites. The degradation profiles and mechanical properties were monitored in phosphate buffered saline (PBS) at 37°C for 28 days. ISP composites revealed significantly less media uptake and mass loss (pproperties of ISP composites were substantially higher (p<0.0001) than those of the LS composites, which showed that the ISP manufacturing process provided a significantly enhanced reinforcement effect than the LS process. During the degradation study, statistically higher flexural property retention profiles were also seen for the ISP composites compared to LS composites. SEM micrographs of fracture surfaces for the LS composites revealed dry fibre bundles and poor fibre dispersion with polymer rich zones, which indicated poor interfacial bonding, distribution and adhesion. In contrast, evenly distributed fibres without dry fibre bundles or polymer rich zones, were clearly observed for the ISP composite samples, which showed that a superior fibre/matrix interface was achieved with highly improved adhesion. Copyright © 2015 Elsevier Ltd. All rights reserved.

  7. Plutonium solubilities

    International Nuclear Information System (INIS)

    Puigdomnech, I.; Bruno, J.

    1991-02-01

    Thermochemical data has been selected for plutonium oxide, hydroxide, carbonate and phosphate equilibria. Equilibrium constants have been evaluated in the temperature range 0 to 300 degrees C at a pressure of 1 bar to T≤100 degrees C and at the steam saturated pressure at higher temperatures. Measured solubilities of plutonium that are reported in the literature for laboratory experiments have been collected. Solubility data on oxides, hydroxides, carbonates and phosphates have been selected. No solubility data were found at temperatures higher than 60 degrees C. The literature solubility data have been compared with plutonium solubilities calculated with the EQ3/6 geochemical modelling programs, using the selected thermodynamic data for plutonium. (authors)

  8. The dosimetric properties of phosphate glass systems prepared by different chemical nanomaterials.

    Science.gov (United States)

    Abdelhalim, Mohamed Anwar K; Al-Shamrani, Bandar Mora

    2016-12-01

    The synthesis and characterization of glass systems were carried out using prepared nanocrystals injected into a glass matrix as a thermoluminescence (TL) activator using the melt-quenching method. Sample 1 was prepared as [40P 2 O 5 50BaO:2.5MgO, 2.5Na 2 O, 5TiO 2 ], sample 2 as [37.5P 2 O 5 37.5CaO:25TiO 2 ] and sample 3 as [50P 2 O 5 -50Li 2 O]. Formation of the synthesized compound was confirmed by studying the X-ray diffraction (XRD) patterns and scanning electron microscopy (SEM) images. An annealing procedure was carried out for 1 h at 400 °C. The glow curve position and shape shifted dramatically and linearly to the higher temperature values on increasing the heating rate. A heating rate of 30 °C/s was the most suitable for obtaining a high TL response. Samples 2 and 3 have the highest TL response, which approached the effective atomic number (Z eff ) of natural bone. The observed TL sensitivity of the prepared samples 2 and 3 is less than that of commercially available 'TLD-200 chips' and LiF:Mg,Ti (TLD-100) phosphor. Sample [37.5P 2 O 5 37.5CaO:25TiO 2 ] would be useful in personal and environmental dosimetry for measuring high doses of gamma radiation. Sample [50P 2 O 5 -50Li 2 O] is a good dosimeter, although it requires the addition of an appropriate transitional metal (activator) to overcome the problem of high fading. Copyright © 2016 John Wiley & Sons, Ltd. Copyright © 2016 John Wiley & Sons, Ltd.

  9. Thermal analyzes of phosphate glasses doped with Yb{sup 3+} and ZnTe nanocrystals

    Energy Technology Data Exchange (ETDEWEB)

    Freitas, A.M.; Bell, M.J.V. [Laboratório de Espectroscopia de Materiais, Departamento de Física, ICE, Universidade Federal de Juiz de Fora, 36036-330 Juiz de Fora, MG (Brazil); Anjos, V., E-mail: virgilio@fisica.ufjf.br [Laboratório de Espectroscopia de Materiais, Departamento de Física, ICE, Universidade Federal de Juiz de Fora, 36036-330 Juiz de Fora, MG (Brazil); Pinheiro, A.S.; Dantas, N.O. [Laboratório de Novos Materiais Isolantes e Semicondutores (LNMIS), Instituto de Física da Universidade Federal de Uberlândia, CP 593, CEP 38400-902 Uberlândia, MG (Brazil)

    2016-01-15

    This work studies the thermal properties of a glass matrix called PZABP doped with ZnTe and co-doped with Yb{sup 3+} with nominal composition 60P{sub 2}O{sub 5}, 15ZnO, 5Al{sub 2}O{sub 3}, 10BaO, and 10 PbO (mol%). The presence of ZnTe results in the formation of nanocrystals which are evidenced by optical absorption, X-Ray Diffraction (XRD) and Raman scattering. Thermal lens and Volumetric Heat Capacity techniques were used to investigate thermal diffusivity (D), thermal conductivity (K) and optical path variation with temperature (ds/dT). The outcomes indicate high values for the thermal diffusivity and a relatively small thermal conductivity, i.e., around 2.6×10{sup −3} cm{sup 2}/s and 3.4×10{sup −3} W cm{sup −1} K{sup −1}, respectively. On the other hand, a low ds/dT value, 1.0×10{sup −6} K{sup −1}, was obtained as required for an active laser medium. Moreover, it has been observed that the matrix allows high concentration of dopants without compromising its thermal properties. As a result, PZABP glasses may be pointed out as a promising material to applications in high power photonics devices. - Highlights: • UV transparentglass matrix (PZABP) is used for Yb{sup 3+}doping. • Bulk like and quantum dots like crystals of ZnTe were grown. • Thermal properties point out PZABP as a material to high power photonics devices.

  10. Optical properties of highly Er{sup 3+}-doped sodium-aluminium-phosphate glasses for broadband 1.5 {mu}m emission

    Energy Technology Data Exchange (ETDEWEB)

    Reddy, A. Amarnath [Nanophotonics Laboratory, Department of Physics, Indian Institute of Technology Delhi, Hauz Khas, New Delhi 110016 (India); Babu, S. Surendra [Laser Instrumentation Design Centre, Instrument Research and Development Establishment, Dehradun 248008 (India); Pradeesh, K. [Nanophotonics Laboratory, Department of Physics, Indian Institute of Technology Delhi, Hauz Khas, New Delhi 110016 (India); Otton, C.J. [Valencia Nanophotonics Technology Center, Universidad Politecnica de Valencia, 46022 Valencia (Spain); Vijaya Prakash, G., E-mail: prakash@physics.iitd.ac.in [Nanophotonics Laboratory, Department of Physics, Indian Institute of Technology Delhi, Hauz Khas, New Delhi 110016 (India)

    2011-03-03

    Research highlights: > Highly Er{sup 3+} doped phosphate glasses for the 1.54 {mu}m laser emission were explored. > Emission from these doped glasses shows larger lifetimes and quantum efficiencies. > Optical amplifier parameters are greater than other reported phosphate glasses. > The durability and obtained results are most favourable for short-length amplifiers. - Abstract: Erbium-doped Na{sub 3}Al{sub 2}P{sub 3}O{sub 12} (NAP) glasses with compositions 92NAP-(8-x)Al{sub 2}O{sub 3}-(x)Er{sub 2}O{sub 3} (where x = 2-8) were prepared and characterized for absorption, visible and NIR emission and decay time properties. Judd-Ofelt analysis has been carried out to predict radiative properties of luminescent levels of Er{sup 3+} ions. Comparatively larger photoluminescence lifetimes (7.86 ms) and larger quantum efficiencies (74%) for the laser transition, {sup 4}I{sub 13/2} {yields} {sup 4}I{sub 15/2} (at 1.54 {mu}m) are observed. The moisture insensitivity, large Er{sup 3+} ion doping capability and relatively high-gain and broad emission at 1.5 {mu}m are the most notable features of these glasses to realize efficient short-length optical amplifiers.

  11. X-ray absorption spectroscopy and high-energy XRD study of the local environment of copper in antibacterial copper-releasing degradable phosphate glasses

    OpenAIRE

    Pickup, David M.; Ahmed, Ifty; Fitzgerald, Victoria; Moss, Rob M.; Wetherall, Karen; Knowles, Jonathan C.; Smith, Mark E.; Newport, Robert J.

    2006-01-01

    Phosphate-based glasses of the general formula Na2O-CaO-P2O5 are degradable in an aqueous environment, and therefore can act as antibacterial materials through the inclusion of ions such as copper. In this study, CuO and Cu2O were added to Na2O-CaO-P2O5 glasses (1-20 mol% Cu) and X-ray absorption spectroscopy (XAS) and high-energy X-ray diffraction (HEXRD) used to probe the local environment of the copper ions. Copper K-edge X-ray absorption near-edge structure (XANES) spectra confirm the oxi...

  12. Phosphate fertilizers with varying water-solubilities applied to Amazonian soils: I. agronomic efficiency of P sources

    International Nuclear Information System (INIS)

    Brasil, E.C.; Muraoka, T.; Boaretto, A.E.; Scivittaro, W.B.

    2002-01-01

    The relative agronomic efficiency of four phosphate sources (triple superphosphate, ordinary Yoorin thermophosphate, coarse Yoorin thermophosphate and North Carolina phosphate rock) were evaluated, in a pot experiment carried out under greenhouse conditions, using five soils (medium texture Yellow Latosol, clayey Yellow Latosol, very clayey Yellow Latosol, clayey Red-Yellow Podzolic and very clayey Red-Yellow Podzolic) from Para State, Brazil. The soils received three rates of phosphorus (40, 80 and 120 mg P/kg of soil) plus the control (0P) treatment. A randomized block design with three replicates was used. Two consecutive crops (cowpea and rice) were used as test plants. The results showed that the best dry matter yield and P uptake for cowpea were obtained in soils fertilized with triple superphosphate. The agronomic efficiency index of ordinary Yoorin was superior to the coarse Yoorin and North Carolina phosphate rock for the cowpea grown as first crop. The indices were similar for all phosphate sources for the subsequent rice crop. The best residual effect was obtained with North Carolina phosphate rock and coarse Yoorin. The larger particle size of coarse thermophosphate resulted in a decreased P efficiency. (author)

  13. Electronic polarizability, optical basicity and interaction parameter for Nd{sub 2}O{sub 3} doped lithium-zinc-phosphate glasses

    Energy Technology Data Exchange (ETDEWEB)

    Algradee, M.A.; Sultan, M.; Samir, O.M.; Alwany, A.E.B. [Ibb University, Department of Physics, Faculty of Science, Ibb (Yemen)

    2017-08-15

    The Nd{sup 3+}-doped lithium-zinc-phosphate glasses were prepared by means of conventional melt quenching method. X-ray diffraction results confirmed the glassy nature of the studied glasses. The physical parameters such as the density, molar volume, ion concentration, polaron radius, inter-ionic distance, field strength and oxygen packing density were calculated using different formulae. The transmittance and reflectance spectra of glasses were recorded in the wavelength range 190-1200 nm. The values of optical band gap and Urbach energy were determined based on Mott-Davis model. The refractive indices for the studied glasses were evaluated from optical band gap values using different methods. The average electronic polarizability of the oxide ions, optical basicity and an interaction parameter were investigated from the calculated values of the refractive index and the optical band gap for the studied glasses. The variations in the different physical and optical properties of glasses with Nd{sub 2}O{sub 3} content were discussed in terms of different parameters such as non-bridging oxygen and different concentrations of Nd cation in glass system. (orig.)

  14. Cytocompatibility and Mechanical Properties of Short Phosphate Glass Fibre Reinforced Polylactic Acid (PLA Composites: Effect of Coupling Agent Mediated Interface

    Directory of Open Access Journals (Sweden)

    Gavin Walker

    2012-10-01

    Full Text Available In this study three chemical agents Amino-propyl-triethoxy-silane (APS, sorbitol ended PLA oligomer (SPLA and Hexamethylene diisocyanate (HDI were identified to be used as coupling agents to react with the phosphate glass fibre (PGF reinforcement and the polylactic acid (PLA polymer matrix of the composite. Composites were prepared with short chopped strand fibres (l = 20 mm, ϕ = 20 µm in a random arrangement within PLA matrix. Improved, initial composite flexural strength (~20 MPa was observed for APS treated fibres, which was suggested to be due to enhanced bonding between the fibres and polymer matrix. Both APS and HDI treated fibres were suggested to be covalently linked with the PLA matrix. The hydrophobicity induced by these coupling agents (HDI, APS helped to resist hydrolysis of the interface and thus retained their mechanical properties for an extended period of time as compared to non-treated control. Approximately 70% of initial strength and 65% of initial modulus was retained by HDI treated fibre composites in contrast to the control, where only ~50% of strength and modulus was retained after 28 days of immersion in PBS at 37 °C. All coupling agent treated and control composites demonstrated good cytocompatibility which was comparable to the tissue culture polystyrene (TCP control, supporting the use of these materials as coupling agent’s within medical implant devices.

  15. Theoretical Studies of the Spin Hamiltonian Parameters and Local Distortions for Cu2+ in Alkaline Earth Lead Zinc Phosphate Glasses

    Science.gov (United States)

    Wang, Bo-Kun; Wu, Shao-Yi; Yuan, Zi-Yi; Liu, Zi-Xuan; Jiang, Shi-Xin; Liu, Zheng; Yao, Zi-Jian; Teng, Bao-Hua; Wu, Ming-He

    2016-08-01

    The spin Hamiltonian parameters and local structures are theoretically studied for Cu2+-doped alkaline earth lead zinc phosphate (RPPZ, R=Mg, Ca, Sr, and Ba) glasses based on the high-order perturbation calculations for a tetragonally elongated octahedral 3d9 cluster. The relative elongation ratios are found to be ρ≈3.2%, 4.4%, 4.6%, and 3.3% for R=Mg, Ca, Sr, and Ba, respectively, because of the Jahn-Teller effect. The whole decreasing crystal-field strength Dq and orbital reduction factor k from Mg to Sr are ascribed to the weakening electrostatic coulombic interactions and the increasing probability of productivity of nonbridge oxygen (and hence increasing Cu2+-O2- electron cloud admixtures) under PbO addition, respectively, with increasing alkali earth ionic radius. The anomalies (the largest Dq and the next highest k among the systems) for R=Ba are attributed to the cross linkage of this large cation in the network. The overall increasing order (Mg≤Bacontaining copper dopants.

  16. Structural and luminescence behavior of Sm{sup 3+} ions doped lead boro-telluro-phosphate glasses

    Energy Technology Data Exchange (ETDEWEB)

    Selvi, S.; Marimuthu, K.; Muralidharan, G., E-mail: muraligru@gmail.com

    2015-03-15

    The Sm{sup 3+} ions doped lead boro-telluro-phosphate glasses with the chemical composition 30H{sub 3}O{sub 3}+(20–x)PbO+15TeO{sub 2}+10P{sub 2}O{sub 5}+10ZnO+15BaCO{sub 3}+xSm{sub 2}O{sub 3} (x=0.05, 0.1, 0.25, 0.5, 1.0 and 2.0 in wt%) have been prepared by a melt quenching technique and their structural and optical behavior were studied and reported. The physical properties like, refractive index, density and dielectric constant etc., have been estimated. FTIR and Raman spectral studies have been made to explore the presence of functional groups and various structural units in the prepared glasses. The formation of bridging and non-bridging oxygens of BO{sub 4}, BO{sub 3}, TeO{sub 3}, TeO{sub 6} and PbO{sub 4} structural units have been investigated. From the absorption spectra, the direct (n=1/2), indirect (n=2) band gap, band tailing parameter (B) and Urbach energy (ΔE) values were estimated. The ionic nature of the metal–ligand bond in the title glasses has been discussed. The Judd–Ofelt intensity parameters (Ω{sub λ,}λ=2, 4, and 6), oscillator strength of ƒ−ƒ electric dipole transitions and transition probability (A) have been evaluated. The predicted radiative lifetime (τ{sub rad}) and branching ratio (β{sub R}) values of the {sup 4}G{sub 5/2} excited level of the Sm{sup 3+} ions to the lower energy levels were determined and compared with the experimentally measured values. From the recorded fluorescence spectra, the strong transitions of Sm{sup 3+} ions {sup 4}G{sub 5/2}→{sup 6}H{sub 5/2} (565 nm), {sup 4}G{sub 5/2}→{sup 6}H{sub 7/2} (602 nm), {sup 4}G{sub 5/2}→{sup 6}H{sub 9/2} (648 nm) and a weak transition, {sup 4}G{sub 5/2}→{sup 6}H{sub 11/2} (709 nm) have been observed. The significant laser parameters like, gain bandwidth (σ{sub p}{sup E}×λ{sub eff}), optical gain (σ{sub p}{sup E}×τ{sub rad}) and stimulated emission cross-section (σ{sub p}{sup E}) values were estimated for the {sup 4}G{sub 5/2}→{sup 6}H{sub J} (J=5

  17. A comparative study of retentive strengths of zinc phosphate, polycarboxylate and glass ionomer cements with stainless steel crowns - an in vitro study.

    Science.gov (United States)

    Raghunath Reddy, M H; Subba Reddy, V V; Basappa, N

    2010-01-01

    An in vitro study was conducted to compare the retentive strengths of zinc phosphate, polycarboxylate and glass ionomer cements using Instron universal testing machine. Thirty preformed and pretrimmed stainless steel crowns were used for cementation on 30 extracted human primary molars which were divided into three groups of 10 teeth in each group. Then the teeth were stored in artificial saliva and incubated at 37°C for 24 h. A load was applied on to the crown and was gradually increased till the crown showed dislodgement, and then the readings were recorded using Instron recorder and analyzed for statistical significance. The surface area of crown was measured by graphical method. The retentive strength was expressed in terms of kg/cm 2 , which was calculated by the equation load divided by area. Retentive strengths of zinc phosphate (ranged from a minimum of 16.93 to amaximum of 28.13 kg/cm 2 with mean of 21.28 kg/cm 2 ) and glass ionomer cement (minimum of 13.69 - 28.15 kg/cm 2 with mean of 20.69 kg/cm 2 ) were greater than that of polycarboxylate cement (minimum of 13.26 - 22.69 kg/cm 2 with mean of 16.79 kg/cm 2 ). Negligible difference (0.59 kg/cm 2 ) of retentive strength was observed between zinc phosphate (21.28 kg/cm 2 ) and glass ionomer cements (20.69 kg/cm 2 ). Glass ionomer cements can be recommended for cementation of stainless steel crowns because of its advantages and the retentive strength was almost similar to that of zinc phosphate cement.

  18. A comparative study of retentive strengths of zinc phosphate, polycarboxylate and glass ionomer cements with stainless steel crowns - An in vitro study

    Directory of Open Access Journals (Sweden)

    Raghunath Reddy M

    2010-01-01

    Full Text Available An in vitro study was conducted to compare the retentive strengths of zinc phosphate, polycarboxylate and glass ionomer cements using Instron universal testing machine. Thirty preformed and pretrimmed stainless steel crowns were used for cementation on 30 extracted human primary molars which were divided into three groups of 10 teeth in each group. Then the teeth were stored in artificial saliva and incubated at 37°C for 24 h. A load was applied on to the crown and was gradually increased till the crown showed dislodgement, and then the readings were recorded using Instron recorder and analyzed for statistical significance. The surface area of crown was measured by graphical method. The retentive strength was expressed in terms of kg/cm 2 , which was calculated by the equation load divided by area. Retentive strengths of zinc phosphate (ranged from a minimum of 16.93 to amaximum of 28.13 kg/cm 2 with mean of 21.28 kg/cm 2 and glass ionomer cement (minimum of 13.69 - 28.15 kg/cm 2 with mean of 20.69 kg/cm 2 were greater than that of polycarboxylate cement (minimum of 13.26 - 22.69 kg/cm 2 with mean of 16.79 kg/cm 2 . Negligible difference (0.59 kg/cm 2 of retentive strength was observed between zinc phosphate (21.28 kg/cm 2 and glass ionomer cements (20.69 kg/cm 2 . Glass ionomer cements can be recommended for cementation of stainless steel crowns because of its advantages and the retentive strength was almost similar to that of zinc phosphate cement.

  19. Optical properties and energy transfer behavior from Tb{sup 3+} to Mn{sup 2+} ions in co-doped zinc strontium phosphate glasses

    Energy Technology Data Exchange (ETDEWEB)

    Liang Xiaoluan [Key Laboratory for Ultrafine Materials of Ministry of Education, School of Materials Science and Engineering, East China University of Science and Technology, Shanghai 200237 (China); Xing Zhongwen [Department of Materials Science and Engineering, Nanjing University, Nanjing 210093 (China); Liu Yinyao; Xu Weina; Yang Yunxia [Key Laboratory for Ultrafine Materials of Ministry of Education, School of Materials Science and Engineering, East China University of Science and Technology, Shanghai 200237 (China); Chen Guorong, E-mail: grchen@ecust.edu.cn [Key Laboratory for Ultrafine Materials of Ministry of Education, School of Materials Science and Engineering, East China University of Science and Technology, Shanghai 200237 (China)

    2011-10-17

    Highlights: {yields} We choose Tb{sup 3+} as the sensitizer to enhance the emission of Mn{sup 2+} ions in ZSP glasses. {yields} We make a serious of characterization on the optical properties of the glasses. {yields} Tb{sup 3+} can transfer its energy to the neighbor Mn{sup 2+} during excitation process. {yields} The energy transfer mechanism is dipolar-quadrupole interaction in phosphate glasses. {yields} Meanwhile, this process is taken by two modes: cross-relaxation and resonant transfer. - Abstract: In this paper, we report optical properties and energy transfer behavior between Tb and Mn in zinc strontium phosphate glasses. Electron Paramagnetic Resonance spectra indicate a stronger hyperfine interaction of Mn{sup 2+}-Mn{sup 2+} pairs with higher MnO concentrations. The co-existence of Tb{sup 3+} and Mn{sup 2+} ions in glasses is clearly evident in the transmittance spectra. Emission spectra show an obvious energy transfer from Tb{sup 3+} to Mn{sup 2+} ions in glasses. Based on Dexter's energy transfer formula and Reisfeld's approximation, the energy transfer mechanism was postulated to proceed via a dipolar-quadrupole interaction. The energy transfer carries out with resonant and cross-relaxation transfer modes with the understanding of Tb{sup 3+} and Mn{sup 2+} energy level diagrams. The decreasing in mean-duration time ({tau}{sub mean}) of Tb{sup 3+} ions obtained from the decay curves make a further evidence of energy transfer from Tb{sup 3+} to Mn{sup 2+} ions in glasses.

  20. 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....

  1. A comparative study of retentive strengths of zinc phosphate, polycarboxylate and glass ionomer cements with stainless steel crowns--an in vitro study.

    Science.gov (United States)

    Reddy, R; Basappa, N; Reddy, V V

    1998-03-01

    This study was conducted on 30 extracted human primary molars to assess the retentive strengths of zinc phosphate, polycarboxylate and glass ionomer cements. The teeth were embedded in resin blocks and were randomly divided into 3 groups of 10 each. The occlusal surfaces of all teeth were reduced uniformly by 1.0 to 1.5 mm. All mesial, distal undercuts were removed and sharp angles rounded. This was followed by cementing pretrimmed and precontoured stainless steel crowns on each tooth with hand pressure and storing in artificial saliva at 37 degrees C for 24 hours. Retentive strength was tested using Instron Universal Testing Machine. The load was applied starting from a zero reading and gradually increased until the cemented stainless steel crowns showed signs of movement and then the readings were recorded. It was found that retentive strengths of zinc phosphate and glass ionomer cements were statistically better (P cement. Negligible difference (0. 59 kg/cm2) was however observed between zinc phosphate and glass ionomer cements.

  2. Inclusion of piroxicam in mesoporous phosphate glass-ceramic and evaluation of the physiochemical characteristics.

    Science.gov (United States)

    Javadzadeh, Yousef; Bairami Atashgah, Rahimeh; Barzegar-Jalali, Mohammad; Soleimani, Farshad; Mohammadi, Ghobad; Sabzevari, Araz; Adibkia, Khosro

    2014-04-01

    The mesoporous glass-ceramic (GC) was employed as a carrier to investigate its capability for pharmaceutical applications. Piroxicam (PX) as a model drug was loaded in the GC by using of solvent evaporation technique. The physicochemical properties and morphology of the powders were evaluated employing X-ray powder diffractometry (XRPD), differential scanning calorimetry (DSC), Fourier-transform infrared spectroscopy (FT-IR), and scanning electron microscopy (SEM). The drug adsorption isotherms were assessed as well. Drug release profiles were examined by fitting the data to the 10 common kinetic models. The specific surface area, Vm (the volume of the N2 adsorbed on the 1g of the GC when the monolayer is complete) and the average pore diameter of the GC powder before and after loading process were measured by the Brunauer-Emmett-Teller (BET) and Barrett-Joyner-Halenda (BJH) analysis benefiting N2 adsorption/desorption isotherms. The ideal loading of PX in the GC was 41.8%. The average pore diameter for the GC was determined to be about 10nm. The Freundlich model was found to be the best adsorption isotherm. Decrease of the GC specific surface area and Vm values were observed after loading process. Drug release data were best fitted to the Weibull model with the shape factor of 0.4-0.7 signifying the Fickian diffusion of PX from the GC. Accordingly, the GC could be considered as a suitable adsorbent to develop an oral drug delivery system. Copyright © 2014 Elsevier B.V. All rights reserved.

  3. Surface degradation of glass ceramics after exposure to acidulated phosphate fluoride

    Science.gov (United States)

    CCAHUANA, Vanessa Zulema S.; ÖZCAN, Mutlu; MESQUITA, Alfredo Mikail Melo; NISHIOKA, Renato Sussumo; KIMPARA, Estevão Tomomitsu; BOTTINO, Marco Antonio

    2010-01-01

    Objective This study evaluated the surface degradation effect of acidulated phosphate fluoride (APF) gel exposure on the glassy matrix ceramics as a function of time. Material and methods Disc-shaped ceramic specimens (N = 120, 10/per ceramic material) were prepared in stainless steel molds (inner diameter: 5 mm, height: 2 mm) using 6 dental ceramics: 3 indicated for ceramic-fused-to-metal (Vita Omega 900, Carmen and Vita Titankeramik), 2 for all-ceramic (Vitadur Alpha and Finesse® Low Fusing) and 1 for both types of restorations (IPS d.SIGN). The specimens were wet ground finished, ultrasonically cleaned and auto-glazed. All specimens were subjected to calculation of percentage of mass loss, surface roughness analysis and topographical description by scanning electron microscopy (SEM) before (0 min) and after exposure to 1.23 % APF gel for 4 min and 60 min representing short- and long-term etching effect, respectively. The data were analyzed using two-way ANOVA with repeated measures and Tukey`s test (α=0.05). Results Significant effect of the type of the ceramics (p=0.0000, p=0.0031) and exposure time (p=0.0000) was observed in both surface roughness and percentage of mass loss values, respectively. The interaction factor between both parameters was also significant for both parameters (p=0.0904, p=0.0258). Both 4 min (0.44±0.1 - 0.81±0.2 µm) and 60 min (0.66±0.1 - 1.04±0.3 µm) APF gel exposure created significantly more surface roughness for all groups when compared to the control groups (0.33±0.2 - 0.68±0.2 µm) (p0.05) but at 60 min exposure, IPS d.SIGN showed the highest percentage of mass loss (0.1151±0.11). The mean surface roughness for Vita Titankeramik (0.84±0.2 µm) and Finesse® Low Fusing (0.74.±0.2 µm) was significantly higher than those of the other ceramics (0.59±0.1 µm - 0.49±0.1 µm) and Vita Titankeramik (pcorrosive attack on all of ceramics at varying degrees. Conclusions The ceramics indicated for either metal-ceramic or all

  4. Spatially selective Au nanoparticle growth in laser-quality glass controlled by UV-induced phosphate-chain cross-linkage

    International Nuclear Information System (INIS)

    Sigaev, Vladimir N; Savinkov, Vitaly I; Lotarev, Sergey V; Shakhgildyan, Georgiy Yu; Paleari, Alberto; Lorenzi, Roberto

    2013-01-01

    Herein we describe how UV excitation of localized electronic states in phosphate glasses can activate structural rearrangements that influence the kinetics of Au nanoparticle (NP) thermal growth in Au-doped glass. The results suggest a novel strategy to address the problem of controlling nano-assembly processes of metal NP patterns in fully inorganic and chemically stable hard materials, such as laser-quality glasses. We show that the mechanism is promoted by opening and subsequent cross-linkage of phosphate chains under UV excitation of non-bridging groups in the amorphous network of the glass, with a consequent modification of Au diffusion and metal NP growth. Importantly, the micro-Raman mapping of the UV-induced modifications demonstrates that the process is restricted within the beam waist region of the focused UV laser beam. This fact is consistent with the need for more than one excitation event, close in time and in space, in order to promote structural cross-linkage and Au diffusion confinement. The stability of the photo-induced modifications makes it possible to design new metal patterning approaches for the fabrication of three-dimensional metal structures in laser-quality materials for high-power nonlinear applications. (paper)

  5. Multi-layer porous fiber-reinforced composites for implants: in vitro calcium phosphate formation in the presence of bioactive glass.

    Science.gov (United States)

    Nganga, Sara; Zhang, Di; Moritz, Niko; Vallittu, Pekka K; Hupa, Leena

    2012-11-01

    Glass-fiber-reinforced composites (FRCs), based on bifunctional methacrylate resin, have recently shown their potential for use as durable cranioplasty, orthopedic and oral implants. In this study we suggest a multi-component sandwich implant structure with (i) outer layers out of porous FRC, which interface the cortical bone, and (ii) inner layers encompassing bioactive glass granules, which interface with the cancellous bone. The capability of Bioglass(®) 45S5 granules (100-250μm) to induce calcium phosphate formation on the surface of the FRC was explored by immersing the porous FRC-Bioglass laminates in simulated body fluid (SBF) for up to 28d. In both static (agitated) and dynamic conditions, bioactive glass granules induced precipitation of calcium phosphate at the laminate surfaces as confirmed by scanning electron microscopy. The proposed dynamic flow system is useful for the in vitro simulation of bone-like apatite formation on various new porous implant designs containing bioactive glass and implant material degradation. Copyright © 2012 Academy of Dental Materials. Published by Elsevier Ltd. All rights reserved.

  6. Spatially selective Au nanoparticle growth in laser-quality glass controlled by UV-induced phosphate-chain cross-linkage.

    Science.gov (United States)

    Sigaev, Vladimir N; Savinkov, Vitaly I; Lotarev, Sergey V; Shakhgildyan, Georgiy Yu; Lorenzi, Roberto; Paleari, Alberto

    2013-06-07

    Herein we describe how UV excitation of localized electronic states in phosphate glasses can activate structural rearrangements that influence the kinetics of Au nanoparticle (NP) thermal growth in Au-doped glass. The results suggest a novel strategy to address the problem of controlling nano-assembly processes of metal NP patterns in fully inorganic and chemically stable hard materials, such as laser-quality glasses. We show that the mechanism is promoted by opening and subsequent cross-linkage of phosphate chains under UV excitation of non-bridging groups in the amorphous network of the glass, with a consequent modification of Au diffusion and metal NP growth. Importantly, the micro-Raman mapping of the UV-induced modifications demonstrates that the process is restricted within the beam waist region of the focused UV laser beam. This fact is consistent with the need for more than one excitation event, close in time and in space, in order to promote structural cross-linkage and Au diffusion confinement. The stability of the photo-induced modifications makes it possible to design new metal patterning approaches for the fabrication of three-dimensional metal structures in laser-quality materials for high-power nonlinear applications.

  7. Mineralization of soluble P fertilizers and insoluble rock phosphate in response to phosphate-solubilizing bacteria and poultry manure and their effect on the growth and P utilization efficiency of chilli (Capsicum annuum L.)

    Science.gov (United States)

    Abbasi, M. K.; Musa, N.; Manzoor, M.

    2015-08-01

    The ability of soil microorganisms and organic manure to convert insoluble phosphorus (P) to an accessible form offers a biological rescue system for improving P utilization efficiency in soil-plant systems. Our objective was to examine the P mineralization potential of two soluble P fertilizers (SPF), i.e., single superphosphate (SSP) and diammonium phosphate (DAP), and of insoluble rock phosphate (RP) with and without phosphate-solubilizing bacteria (PSB) and poultry manure (PM) and their subsequent effect on the growth, yield and P utilization efficiency (PUE) of chilli (Capsicum annuum L.). An incubation study was carried out on a loam (slightly alkaline) soil with 12 treatments: T0 - control; T1 - RP; T2 - SSP; T3 - DAP; T4 - PM; T5 - 1/2 RP+1/2 SSP; T6 - 1/2 RP+1/2 DAP; T7 - 1/2 RP+1/2 PM; T8 - RP+PSB; T9 - 1/2 RP+1/2 SSP+PSB; T10 - 1/2 RP+1/2 DAP+PSB; and T11 - 1/2 RP+1/2 PM+PSB. Phosphorus mineralization was measured by analyzing extractable P from the amended soil incubated under controlled conditions at 25 °C for periods of 0, 5, 15, 25, 35 and 60 days. A complementary greenhouse experiment was conducted in pots with chilli (Capsicum annuum L.) as a test crop. Growth, yield, P uptake and PUE of the chilli was determined during the study. Results indicated that P mineralization in soil amended with RP was 6.0-11.5 mg kg-1, while both soluble P fertilizers resulted in 68-73 mg P kg-1 at day 0, which decreased by 79-82 % at the end of incubation. The integrated use of PSB and PM with RP in T11 stimulated P mineralization by releasing a maximum of 25 mg P kg-1 that was maintained at high levels without any loss. Use of PSB decreased soil pH. In the greenhouse experiment, RP alone or RP+PSB did not have a significant impact on plant growth. However, the combined use of RP, PM and PSB in T11 resulted in similar growth, yield and P uptake of chilli as DAP. The PUE of applied P varied from 4 to 29 % and was higher in the treatments that included PSB. We conclude

  8. The effect of ZrO2 and TiO 2 on solubility and strength of apatite-mullite glass-ceramics for dental applications.

    Science.gov (United States)

    Fathi, Hawa M; Miller, Cheryl; Stokes, Christopher; Johnson, Anthony

    2014-03-01

    The effect of ZrO2 and TiO2 on the chemical and mechanical properties of apatite-mullite glass-ceramics was investigated after sample preparation according to the ISO (2768:2008) recommendations for dental ceramics. All materials were characterized using differential thermal analysis, X-ray diffraction, scanning electron microscopy and energy dispersive spectroscopy. X-ray fluorescence spectroscopy was used to determine the concentrations of elements present in all materials produced. The chemical solubility test and the biaxial flexural strength (BFS) test were then carried out on all the samples. The best solubility value of 242 ± 61 μg/cm(2) was obtained when HG1T was heat-treated for 1 h at the glass transition temperature plus 20 °C (Tg + 20 °C) followed by 5 h at 1200 °C. The highest BFS value of 174 ± 38 MPa was achieved when HG1Z and HG1Z+T were heat-treated for 1 h at the Tg + 20 °C followed by 7 h at 1200 °C. The present study has demonstrated that the addition of TiO2 to the reference composition showed promise in both the glass and heat-treated samples. However, ZrO2 is an effective agent for developing the solubility or the mechanical properties of an apatite-mullite glass-ceramic separately but does not improve the solubility and the BFS simultaneously.

  9. Development of phosphate glass microspheres containing holmium for selective internal radiotherapy; Desenvolvimento de microesferas de vidro fosfato contendo holmio para uso em radioterapia interna seletiva

    Energy Technology Data Exchange (ETDEWEB)

    Barros Filho, Eraldo Cordeiro

    2016-11-01

    The selective internal radiotherapy is an alternative for some kinds of cancer as the hepatocellular carcinoma (HCC) or primary liver cancer treatment. In this treatment, glass or polymer microspheres containing radionuclides inside their structure are introduced in the liver through hepatic artery and trapped at the arterioles that feed the tumor. In this work, the development of phosphate glasses containing holmium for production of microspheres and their application in Brazil are proposed. The developed glasses presented suitable chemical durability, density of 2,7(3) g/cm{sup 3}, high thermal stability and the impurities contained therein do not preclude the treatment. The microspheres were produced by the flame method and the gravitational fall method, and were characterized by means of several techniques to evaluate shape, average particle size, activity and biocompatibility suitable for selective internal radiotherapy. Based in the main results, the submission to in vivo tests is proposed. (author)

  10. 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

  11. Investigating the solubility and cytocompatibility of CaO-Na2 O-SiO2 /TiO2 bioactive glasses.

    Science.gov (United States)

    Wren, Anthony W; Coughlan, Aisling; Smith, Courtney M; Hudson, Sarah P; Laffir, Fathima R; Towler, Mark R

    2015-02-01

    This study aims to investigate the solubility of a series of titanium (TiO2 )-containing bioactive glasses and their subsequent effect on cell viability. Five glasses were synthesized in the composition range SiO2 -Na2 O-CaO with 5 mol % of increments TiO2 substituted for SiO2 . Glass solubility was investigated with respect to (1) exposed surface area, (2) particle size, (3) incubation time, and (4) compositional effects. Ion release profiles showed that sodium (Na(+) ) presented high release rates after 1 day and were unchanged between 7 and 14 days. Calcium (Ca(2+) ) release presented a significant change at each time period and was also composition dependent, where a reduction in Ca(2+) release is observed with an increase in TiO2 concentration. Silica (Si(4+) ) release did not present any clear trends while no titanium (Ti(4+) ) was released. Cell numbers were found to increase up to 44%, compared to the growing control population, with a reduction in particle size and with the inclusion of TiO2 in the glass composition. © 2014 Wiley Periodicals, Inc.

  12. Cytocompatibility, mechanical and dissolution properties of high strength boron and iron oxide phosphate glass fibre reinforced bioresorbable composites.

    Science.gov (United States)

    Sharmin, Nusrat; Hasan, Muhammad S; Parsons, Andrew J; Rudd, Chris D; Ahmed, Ifty

    2016-06-01

    In this study, Polylactic acid (PLA)/phosphate glass fibres (PGF) composites were prepared by compression moulding. Fibres produced from phosphate based glasses P2O5-CaO-MgO-Na2O (P45B0), P2O5-CaO-MgO-Na2O-B2O3 (P45B5), P2O5-CaO-MgO-Na2O-Fe2O3 (P45Fe3) and P2O5-CaO-MgO-Na2O-B2O3-Fe2O3 (P45B5Fe3) were used to reinforce the bioresorbable polymer PLA. Fibre mechanical properties and degradation rate were investigated, along with the mechanical properties, degradation and cytocompatibility of the composites. Retention of the mechanical properties of the composites was evaluated during degradation in PBS at 37°C for four weeks. The fibre volume fraction in the composite varied from 19 to 23%. The flexural strength values (ranging from 131 to 184MPa) and modulus values (ranging from 9.95 to 12.29GPa) obtained for the composites matched those of cortical bone. The highest flexural strength (184MPa) and modulus (12.29GPa) were observed for the P45B5Fe3 composite. After 28 days of immersion in PBS at 37°C, ~35% of the strength profile was maintained for P45B0 and P45B5 composites, while for P45Fe3 and P45B5Fe3 composites ~40% of the initial strength was maintained. However, the overall wet mass change of P45Fe3 and P45B5Fe3 remained significantly lower than that of the P45B0 and P45B5 composites. The pH profile also revealed that the P45B0 and P45B5 composites degraded quicker, correlating well with the degradation profile. From SEM analysis, it could be seen that after 28 days of degradation, the fibres in the fractured surface of P45B5Fe3 composites remain fairly intact as compared to the other formulations. The in vitro cell culture studies using MG63 cell lines revealed both P45Fe3 and P45B5Fe3 composites maintained and showed higher cell viability as compared to the P45B0 and P45B5 composites. This was attributed to the slower degradation rate of the fibres in P45Fe3 and P45B5Fe3 composites as compared with the fibres in P45B0 and P45B5 composites. Copyright © 2015

  13. Influence of screw holes and gamma sterilization on properties of phosphate glass fiber-reinforced composite bone plates.

    Science.gov (United States)

    Han, Na; Ahmed, Ifty; Parsons, Andrew J; Harper, Lee; Scotchford, Colin A; Scammell, Brigitte E; Rudd, Chris D

    2013-05-01

    Polymers prepared from polylactic acid (PLA) have found a multitude of uses as medical devices. For a material that degrades, the main advantage is that an implant would not necessitate a second surgical event for removal. In this study, fibers produced from a quaternary phosphate-based glass (PBG) in the system 50P2O5-40CaO-5Na2O-5Fe2O3 were used to reinforce PLA polymer. The purpose of this study was to assess the effect of screw holes in a range of PBG-reinforced PLA composites with varying fiber layup and volume fraction. The flexural properties obtained showed that the strength and modulus values increased with increasing fiber volume fraction; from 96 MPa to 320 MPa for strength and between 4 GPa and 24 GPa for modulus. Furthermore, utilizing a larger number of thinner unidirectional (UD) fiber prepreg layers provided a significant increase in mechanical properties, which was attributed to enhanced wet out and thus better fiber dispersion during production. The effect of gamma sterilization via flexural tests showed no statistically significant difference between the sterilized and nonsterilized samples, with the exception of the modulus values for samples with screw holes. Degradation profiles revealed that samples with screw holes degraded faster than those without screw holes due to an increased surface area for the plates with screw holes in PBS up to 30 days. Scanning electron microscope (SEM) analysis revealed fiber pullout before and after degradation. Compared with various fiber impregnation samples, with 25% volume fraction, 8 thinner unidirectional prepreg stacked samples had the shortest fiber pull-out lengths in comparison to the other samples investigated.

  14. Casein Phosphopeptide-Amorphous Calcium Phosphate Reduces Streptococcus mutans Biofilm Development on Glass Ionomer Cement and Disrupts Established Biofilms.

    Science.gov (United States)

    Dashper, Stuart G; Catmull, Deanne V; Liu, Sze-Wei; Myroforidis, Helen; Zalizniak, Ilya; Palamara, Joseph E A; Huq, N Laila; Reynolds, Eric C

    2016-01-01

    Glass ionomer cements (GIC) are dental restorative materials that are suitable for modification to help prevent dental plaque (biofilm) formation. The aim of this study was to determine the effects of incorporating casein phosphopeptide-amorphous calcium phosphate (CPP-ACP) into a GIC on the colonisation and establishment of Streptococcus mutans biofilms and the effects of aqueous CPP-ACP on established S mutans biofilms. S. mutans biofilms were either established in flow cells before a single ten min exposure to 1% w/v CPP-ACP treatment or cultured in static wells or flow cells with either GIC or GIC containing 3% w/w CPP-ACP as the substratum. The biofilms were then visualised using confocal laser scanning microscopy after BacLight LIVE/DEAD staining. A significant decrease in biovolume and average thickness of S. mutans biofilms was observed in both static and flow cell assays when 3% CPP-ACP was incorporated into the GIC substratum. A single ten min treatment with aqueous 1% CPP-ACP resulted in a 58% decrease in biofilm biomass and thickness of established S. mutans biofilms grown in a flow cell. The treatment also significantly altered the structure of these biofilms compared with controls. The incorporation of 3% CPP-ACP into GIC significantly reduced S. mutans biofilm development indicating another potential anticariogenic mechanism of this material. Additionally aqueous CPP-ACP disrupted established S. mutans biofilms. The use of CPP-ACP containing GIC combined with regular CPP-ACP treatment may lower S. mutans challenge.

  15. Casein Phosphopeptide-Amorphous Calcium Phosphate Reduces Streptococcus mutans Biofilm Development on Glass Ionomer Cement and Disrupts Established Biofilms.

    Directory of Open Access Journals (Sweden)

    Stuart G Dashper

    Full Text Available Glass ionomer cements (GIC are dental restorative materials that are suitable for modification to help prevent dental plaque (biofilm formation. The aim of this study was to determine the effects of incorporating casein phosphopeptide-amorphous calcium phosphate (CPP-ACP into a GIC on the colonisation and establishment of Streptococcus mutans biofilms and the effects of aqueous CPP-ACP on established S mutans biofilms. S. mutans biofilms were either established in flow cells before a single ten min exposure to 1% w/v CPP-ACP treatment or cultured in static wells or flow cells with either GIC or GIC containing 3% w/w CPP-ACP as the substratum. The biofilms were then visualised using confocal laser scanning microscopy after BacLight LIVE/DEAD staining. A significant decrease in biovolume and average thickness of S. mutans biofilms was observed in both static and flow cell assays when 3% CPP-ACP was incorporated into the GIC substratum. A single ten min treatment with aqueous 1% CPP-ACP resulted in a 58% decrease in biofilm biomass and thickness of established S. mutans biofilms grown in a flow cell. The treatment also significantly altered the structure of these biofilms compared with controls. The incorporation of 3% CPP-ACP into GIC significantly reduced S. mutans biofilm development indicating another potential anticariogenic mechanism of this material. Additionally aqueous CPP-ACP disrupted established S. mutans biofilms. The use of CPP-ACP containing GIC combined with regular CPP-ACP treatment may lower S. mutans challenge.

  16. 3 and 4 oxidation state element solubilities in borosilicate glasses. Implement to actinides in nuclear glasses; Solubilite des elements aux degres d'oxydation (3) et (4) dans les verres de borosilicate. Application aux actinides dans les verres nucleaires

    Energy Technology Data Exchange (ETDEWEB)

    Cachia, J.N

    2005-12-15

    In order to ensure optimal radionuclides containment, the knowledge of the actinide loading limits in nuclear waste glasses and also the comprehension of the solubilization mechanisms of these elements are essential. A first part of this manuscript deals with the study of the differences in solubility of the tri and tetravalent elements (actinides and surrogates) particularly in function of the melting temperature. The results obtained indicate that trivalent elements (La, Gd, Nd, Am, Cm) exhibit a higher solubility than tetravalent elements (Hf, Th, Pu). Consequently, it was planned to reduce plutonium at the oxidation state (III), the later being essentially tetravalent in borosilicate glasses. An innovating reduction process of multi-valent elements (cerium, plutonium) using silicon nitride has been developed in a second part of this work. Reduced plutonium-bearing glasses synthesized by Si{sub 3}N{sub 4} addition made it possible to double the plutonium solubility from 2 to 4 wt% at 1200 deg C. A structural approach to investigate the differences between tri and tetravalent elements was finally undertaken. These investigations were carried out by X-rays Absorption Spectroscopy (EXAFS) and NMR. Trivalent rare earth and actinide elements seem to behave as network modifiers while tetravalent elements rather present true intermediaries' behaviour. (author)

  17. Lithium-aluminum-zinc phosphate glasses activated with Tb3+ and Tb3+/Eu3+ for green laser medium, reddish-orange and white phosphor applications

    Science.gov (United States)

    Francisco-Rodriguez, H. I.; Lira, A.; Soriano-Romero, O.; Meza-Rocha, A. N.; Bordignon, S.; Speghini, A.; Lozada-Morales, R.; Caldiño, U.

    2018-05-01

    A spectroscopic analysis of Tb3+ and Tb3+/Eu3+ doped lithium-aluminum-zinc phosphate glasses is performed through their absorbance and photoluminescence spectra, and decay time profiles. Laser parameter values (stimulated emission cross section, effective bandwidth, gain bandwidth and optical gain) were obtained for the terbium 5D4 → 7F5 green emission from the Tb3+ singly-doped glass (LAZT) excited at 350 nm to judge the suitability of the glass phosphor for fiber lasers. A quantum yield of (47.68 ± 0.49)% was measured for the 5D4 level luminescence. Upon 350 nm excitation the LAZT glass phosphor emits green light with a color purity of 65.6% and chromaticity coordinates (0.285, 0.585) very close to those (0.29, 0.60) of European Broadcasting Union illuminant green. The Tb3+/Eu3+codoped glass emission color can be tuned from reddish-orange of 1865 K upon 318 nm excitation to warm white of 3599 K and neutral white of 4049 K upon 359 and 340 nm excitations, respectively. Upon Tb3+ excitation at 340 nm Eu3+ is sensitized by Tb3+ through a non-radiative energy transfer with an efficiency of 0.23-0.26. An electric dipole-dipole interaction might be the dominant mechanism in the Tb3+ to Eu3+ energy transfer taking place into Tb3+ - Eu3+ clusters.

  18. Impact effects of gamma irradiation on the optical and FT infrared absorption spectra of some Nd3+-doped soda lime phosphate glasses

    Science.gov (United States)

    Marzouk, M. A.; Elkashef, I. M.; Elbatal, H. A.

    2018-04-01

    The main aim of the present work is to study by two collective optical and FTIR spectral measurements some prepared Nd2O3-doped soda lime phosphate glasses before and after gamma irradiation with dose (9 Mrad). The spectral data reveal two strong UV absorption peaks which are correlated with unavoidable trace iron impurities beside extended additional characteristic bands due to Nd3+ ions. Gamma irradiation on the undoped glass produces slight decrease of the intensity of the UV absorption and the generation of an induced visible band and these effects are controlled with two photochemical reduction of some Fe3+ ions to Fe2+ ions together with the formation of nonbridging oxygen hole center (NBOHC) or phosphorous oxygen hole center (POHC). The impact effect of gamma irradiation on the spectra of Nd2O3-doped glasses is limited due to suggested shielding behavior of neodymium ions. FT-infrared spectra show vibrational modes due to main Q2-Q3 phosphate groups and the response of gamma irradiation of the IR spectra is low and the limited variations are related to suggested changes in some bond angles and bond lengths which cause the observed decrease to the intensities of some IR bands.

  19. Efficiency of ammonium nitrate phosphates of varying water-soluble phosphorous content for wheat and succeeding maize crop on different soil types

    International Nuclear Information System (INIS)

    Chapke, V.G.; Bhujbal, B.M.; Mistry, K.B.

    1988-01-01

    Efficiency of 32 P labelled ammonium nitrate phosphate (ANP) containding 30, 50 and 90 per cent of water-soluble phosphorus (WSP) vis-a-vis that of entirely water soluble monoammonium orthophosphate (MAP) for wheat and succeeding maize crop on deep black (vertisol), calcareous black (vertisol), alluvial-Tarai (mollisol) and grey brown alluvial (aridisol) soils was examined in greenhouse experiments. Data on wheat indicated that ANP (50 per cent WSP) was, in general, equally efficient to MAP and ANP (90 per cent WSP) in terms of drymatter yield and total uptake of phosphorus in all soils examined, however, the per cent utilization of applied fertilizer was significantly higher for MAP and ANP (90 per cent WSP) than those for ANP (50 per cent WSP) in all soils. In general, ANP (30 per cent WSP) was significantly inferior to MAP and ANP (90 per cent WSP) in all soils. Data on the succeeding maize crop grown to flowering indicated that residual value of ANP (30 per cent WSP) was equal to that of MAP and ANP (90 per cent WSP) in terms of drymatter yield and phosphorus uptake by the four soils examined. Complementary incubation studies conducted upto 60 days on the above four soils at field capacity moisture status indicated highest 0.5 M NaHCO 3 (pH 8.5) extractable phosphorus levels in MAP treatments followed by ANP (50 per cent WSP) and least in ANP (30 per cent WSP) treatments. (author). 4 tables, 4 figures, 19 refs

  20. Phosphorus release capacity of soluble P fertilizers and insoluble rock phosphate in response to phosphate solubilizing bacteria and poultry manure and their effect on plant growth promotion and P utilization efficiency of chilli (Capsicum annuum L.)

    Science.gov (United States)

    Abbasi, M. K.; Musa, N.; Manzoor, M.

    2015-01-01

    The ability of soil microorganisms and organic manures to convert insoluble phosphorus (P) to an accessible form offers a biological rescue system for improving P solubilization and utilization in soil-plant systems. Our objective was to examine the P supplying capacity of soluble P fertilizers (SPF) i.e. single super phosphate (SSP) and di-ammonium phosphate (DAP) and insoluble rock phosphate (RP) after adding phosphate solubilizing bacteria (PSB) and poultry manure (PM) and their subsequent effect on the growth, yield and P-utilization efficiency (PUE) of chill (Capsicum annuum L.). An incubation study was carried-out on a sandy loam neutral soil with twelve treatments including T0: control; T1: RP; T2: SSP; T3: DAP; T4: PM; T5: 1/2 RP + 1/2 SSP; T6: 1/2 RP + 1/2 DAP; T7: 1/2 RP + 1/2 PM; T8: RP + PSB; T9: 1/2 RP + 1/2 SSP + PSB; T10: 1/2 RP + 1/2 DAP + PSB; T11: 1/2 RP + 1/2 PM + PSB. Phosphorus release capacity of added amendments was measured by analyzing extractable P from the amended soil incubated under controlled condition at 25 °C for 0, 5, 15, 25, 35, 60 days period. To complement the incubation study, a greenhouse experiment was conducted in pots with chilli (Capsicum annuum L.) used as a test crop. Growth, yield, P-uptake and PUE of the chilli was determined during the study. Results indicated that P release capacity of soil amended with RP varied between 6.0 and 11.5 mg kg-1 while the soluble P fertilizers i.e. SSP and DAP displayed a maximum of 73 and 68 mg P kg-1 at the start of the experiment (day 0). However, the P released tendency from SSP and DAP declined during incubation and at the end 82 and 79% of P initially present had been lost from the mineral pool. Integrated use of PSB and PM with RP in 1/2 RP + 1/2 PM + PSB treatment stimulated P mineralization by releasing a maximum of 25 mg P kg-1 that was maintained at high levels without any loss. Application of PSB tended to decrease pH showing an acidifying effect on soil. In the greenhouse

  1. Regulation of Soluble Phosphate on the Ability of Phytate Mineralization and β-Propeller Phytase Gene Expression of Pseudomonas fluorescens JZ-DZ1, a Phytate-Mineralizing Rhizobacterium.

    Science.gov (United States)

    Shen, Lan; Wu, Xiao-Qin; Zeng, Qing-Wei; Liu, Hong-Bin

    2016-12-01

    Phytate-mineralizing rhizobacteria (PMR) play an important role in providing phosphorus for the sustainable plant growth. It is important to investigate the ability of PMR to produce phytase under different phosphate levels for its application. The effects of different concentrations of soluble phosphate on the ability of phytate mineralization of Pseudomonas fluorescens JZ-DZ1, a phytate-mineralizing rhizobacterium, were investigated in both solid and liquid media. The results on solid media showed that halo zone width gradually reduced with concentrations of soluble phosphate increasing from 0.05 to 20 mM, indicating the reduction of the ability of phytate mineralization. The results were consistent with the quantitative detection of phytase activity from the overall trend. An 1866-bp β-propeller phytase (BPP) gene (phyPf) was cloned from the strain, and the deduced amino acid sequence of phyPf shared 98 % of identity with a known BPP from Pseudomonas sp. BS10-3 (AJF36073.1). The results of relative real-time quantitative PCR assay showed that the expression of phyPf was induced by a low concentration (0.1 mM) of soluble phosphate, suggesting that BPP secretion was regulated by gene phyPf. The BPP-harboring bacterium P. fluorescens JZ-DZ1 with low phosphate-inducible ability of phytate mineralization could be potentially applied to promote phosphorus uptake for plants in the future.

  2. Near-UV sensitized 1.06 μm emission of Nd{sup 3+} ions via monovalent copper in phosphate glass

    Energy Technology Data Exchange (ETDEWEB)

    Jiménez, José A., E-mail: jose.jimenez@unf.edu [Department of Chemistry, University of North Florida, Jacksonville, FL 32224 (United States); Sendova, Mariana [Optical Spectroscopy & Nano-Materials Lab, New College of Florida, Sarasota, FL 34243 (United States)

    2015-07-15

    Monovalent copper ions effectively incorporated in Nd-containing phosphate glass by a single-step melt-quench method have been established as near-ultraviolet (UV) sensitizers of Nd{sup 3+} ions, resulting in a remarkable {sup 4}F{sub 3/2} → {sup 4}I{sub 11/2} emission at 1.06 μm. The spectroscopic data indicates an efficient energy conversion process. The Cu{sup +} ions first absorb photons broadly around 360 nm, and subsequently transfer the energy from the Stokes-shifted emitting states to resonant Nd{sup 3+} energy levels in the visible. Ultimately, the Nd{sup 3+} electronic excited states decay and the upper lasing state {sup 4}F{sub 3/2} is populated, leading to the enhanced emission at 1.06 μm. The characteristic features of the Cu{sup +} visible emission spectra and the reduced lifetime of the corresponding Cu{sup +} donor states indicate an efficient non-radiative transfer. The Cu{sup +}/Nd{sup 3+} co-doped phosphate glass appears suitable as solid-state laser material with enhanced pump range in the near-UV part of the spectrum and for solar spectral conversion in photovoltaic cells. - Graphical abstract: Display Omitted - Highlights: • Monovalent copper ions effectively stabilized in Nd{sup 3+}-containing phosphate glass. • Enhanced Nd{sup 3+} near-infrared emission observed upon the Cu{sup +} ions incorporation. • Cu{sup +} → Nd{sup 3+} non-radiative energy transfer efficiencies and likely energy transfer pathways evaluated. • Potential for solid-state lasers and solar spectral conversion suggested.

  3. Effect of thermal lens on beam quality and mode matching in LD pumped Er-Yb-codoped phosphate glass microchip laser

    Energy Technology Data Exchange (ETDEWEB)

    Liu Shujing; Song Feng; Cai Hong; Li Teng; Tian Bin; Wu Zhaohui; Tian Jianguo [Photonics Center, Nankai University, Tianjin 300071 (China); Key Laboratory of Advanced Technique and Fabrication for Weak-Light Nonlinear Photonics Materials (Ministry of Education), Nankai University, Tianjin 300457 (China)

    2008-02-07

    The theoretical values of the thermal focal length and laser beam waist are derived from the theoretical model and transformation theory, respectively. The values of thermal focal length, laser beam waist and the far field divergence angle were experimentally measured in a laser diode (LD) pumped erbium-ytterbium(Er-Yb)-codoped phosphate microchip glass laser. As an extension of thermal effect studies, we investigate the role of thermal lens on beam quality and the mode matching between the pump and the laser, which affects laser efficiency in TEM{sub 00} operation. The study shows that the experimental data are in good agreement with the theoretical predictions.

  4. Effect of alkaline earth modifier on the optical and structural properties of Cu2+ doped phosphate glasses as a bandpass filter

    Science.gov (United States)

    Farouk, M.; Samir, A.; El Okr, M.

    2018-02-01

    Glasses of composition [16RO-3Al2O3sbnd 6CuOsbnd 20Na2Osbnd 55P2O5], where R is the alkaline earth (R = Mg, Ca, Sr and Ba mol. %), were prepared by conventional melt quenching technique. The glass samples were characterized by X-ray diffraction, infrared spectroscopy, and spectrophotometer. XRD patterns show no sharp peaks indicating the non-crystalline nature of the prepared glasses. The density and molar volume of the glass systems were determined in order to study their structures. These results revealed that addition of alkaline earth elements leads to the formation of non-bridging oxygens (NBOs) and expands (opens up) the structure. The infrared spectra were analyzed to quantify the present phosphate groups. The optical absorption spectra of Cu2+ ions show the characteristic broadband single of Cu2+ ions in octahedral symmetry. The band gap was estimated following two methodologies. The first method considers the band edge of the transmission, while the second approach relays on the estimated values of the optical constants. A decent agreement for the band gap values using the two methods was obtained.

  5. 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

  6. Assessment of soil phosphorus tests for situations in Australia where reactive phosphate rock and water-soluble fertilizers are used

    International Nuclear Information System (INIS)

    McLaughlin, M.J.

    2002-01-01

    A selection of commonly used soil P tests, which included anion and cation exchange resin membranes, were compared in a glasshouse experiment using subterranean clover, and evaluated in the field at 19 sites from the National Reactive Phosphate Rock Project in 1993 and at 6 sites in 1995. The ability of the soil P tests to predict plant response was used to evaluate the tests. In the glasshouse experiment, the resin test was less effective than the Bray and Colwell tests in its ability to assess the level of plant available P from the different fertilizer treatments. Seventy one percent of the variation in total P content of the subterranean clover tops was explained by resin extractable P values, whereas the Colwell procedure accounted for 81% and the Bray 1 procedure accounted for 78%. Water and CaCl 2 extracts were poor predictors of P content. In the field experiments, all tests evaluated performed poorly in describing the relationship between soil test P and the level of P applied and relative yield and soil test P over a wide range of soil types and environments. The best performing test was the Bray 1 test, though the relationship was poor. (author)

  7. Preparation and studies on surface modifications of calcium-silico-phosphate ferrimagnetic glass-ceramics in simulated body fluid

    International Nuclear Information System (INIS)

    Sharma, K.; Dixit, A.; Singh, Sher; Jagannath,; Bhattacharya, S.; Prajapat, C.L.; Sharma, P.K.; Yusuf, S.M.; Tyagi, A.K.; Kothiyal, G.P.

    2009-01-01

    The structure and magnetic behaviour of 34SiO 2 -(45 - x) CaO-16P 2 O 5 -4.5 MgO-0.5 CaF 2 - x Fe 2 O 3 (where x = 5, 10, 15, 20 wt.%) glasses have been investigated. Ferrimagnetic glass-ceramics are prepared by melt quench followed by controlled crystallization. The surface modification and dissolution behaviour of these glass-ceramics in simulated body fluid (SBF) have also been studied. Phase formation and magnetic behaviour have been studied using XRD and SQUID magnetometer. The room temperature Moessbauer study has been done to monitor the local environment around Fe cations and valence state of Fe ions. X-ray photoelectron spectroscopy (XPS) was used to study the surface modification in glass-ceramics when immersed in simulated body fluid. Formation of bioactive layer in SBF has been ascertained using X-ray photoelectron spectroscopy (XPS) and scanning electron microscopy (SEM). The SBF solutions were analyzed using an absorption spectrophotometer. The magnetic measurements indicated that all these glasses possess paramagnetic character and the [Fe 2+ /Fe 3+ ] ions ratio depends on the composition of glass and varied with Fe 2 O 3 concentration in glass matrix. In glass-ceramics saturation magnetization increases with increase in amount of Fe 2 O 3 . The nanostructure of hematite and magnetite is formed in the glass-ceramics with 15 and 20 wt.% Fe 2 O 3 , which is responsible for the magnetic property of these glass-ceramics. Introduction of Fe 2 O 3 induces several modifications at the glass-ceramics surface when immersed in SBF solution and thereby affecting the surface dissolution and the formation of the bioactive layer.

  8. Raman and FTIR spectra of CeO{sub 2} and Gd{sub 2}O{sub 3} in iron phosphate glasses

    Energy Technology Data Exchange (ETDEWEB)

    Lai, Yuanming, E-mail: laiyuanming@ipm.com.cn [State Key Laboratory of Advanced Technologies for Comprehensive Utilization of Platinum Metals, Kunming Institute of Precious Metals, Kunming 650106 (China); State Key Laboratory Cultivation Base for Nonmetal Composite and Functional Materials, Southwest University of Science and Technology, Mianyang 621010 (China); Liang, Xiaofeng; Yang, Shiyuan [State Key Laboratory Cultivation Base for Nonmetal Composite and Functional Materials, Southwest University of Science and Technology, Mianyang 621010 (China); Liu, Pei; Zeng, Yiming; Hu, Changyi [State Key Laboratory of Advanced Technologies for Comprehensive Utilization of Platinum Metals, Kunming Institute of Precious Metals, Kunming 650106 (China)

    2014-12-25

    Highlights: • The structure of the studied samples has been investigated by Raman and FTIR spectroscopy. • The structure for the all samples has similar features. • The structure consists of predominantly Q{sup 1} with a fraction of Q{sup 0} and Q{sup 2} units. • The Ce and Gd enters in the structure of studied glasses as a network modifier. - Abstract: In the present work, multicomponent oxide samples of composition x(CeO{sub 2} + Gd{sub 2}O{sub 3})–(40 − x)Fe{sub 2}O{sub 3}–60P{sub 2}O{sub 5} (0 ⩽ x ⩽ 8 mol%) were produced by conventional melting method. The samples were investigated to examine the effect of the CeO{sub 2} and Gd{sub 2}O{sub 3} composition on the structure of the iron phosphate glasses system. The X-ray diffraction analysis (XRD) and scanning electron microscopy (SEM) for the x ⩽ 6 mol% samples show all the samples formed homogeneous glass, but for the x = 8 mol% samples show the presence of randomly distributed crystalline phase embedded in an amorphous matrix. The x(CeO{sub 2} + Gd{sub 2}O{sub 3})–(40 − x)Fe{sub 2}O{sub 3}–60P{sub 2}O{sub 5} glass containing 8 mol% CeO{sub 2} and Gd{sub 2}O{sub 3} partially crystallized during annealing and Ce/Gd-rich were identified by EDS in the crystalline phase. The structure of the studied samples has been investigated using Raman and Fourier transform infrared spectroscopy (FTIR). The Raman and FTIR spectra for the samples have analogous spectral features. The Raman and FTIR spectra suggest that the structure is mainly constituted by the pyrophosphate glass based structure, with a part proportion of metaphosphate and orthophosphate structure. Raman and FTIR spectra allowed us to identify the structural units which appear in the structural network of these phosphate glasses and also the network modifier role of cerium and gadolinium ions.

  9. Ridge optical waveguide in an Er3+/Yb3+ co-doped phosphate glass produced by He+ ion implantation combined with Ar+ ion beam etching

    International Nuclear Information System (INIS)

    Tan Yang; Chen Feng; Hu Lili; Xing Pengfei; Chen Yanxue; Wang Xuelin; Wang Keming

    2007-01-01

    This paper reports on the fabrication and characterization of a ridge optical waveguide in an Er 3+ /Yb 3+ co-doped phosphate glass. The He + ion implantation (at energy of 2.8 MeV) is first applied onto the sample to produce a planar waveguide substrate, and then Ar + ion beam etching (at energy of 500 eV) is carried out to construct rib stripes on the sample surface that has been deposited by a specially designed photoresist mask. According to a reconstructed refractive index profile of the waveguide cross section, the modal distribution of the waveguide is simulated by applying a computer code based on the beam propagation method, which shows reasonable agreement with the experimentally observed waveguide mode by using the end-face coupling method. Simulation of the incident He ions at 2.8 MeV penetrating into the Er 3+ /Yb 3+ co-doped phosphate glass substrate is also performed to provide helpful information on waveguide formation

  10. Polycarboxylic acids as network modifiers for water durability improvement of inorganic-organic hybrid tin-silico-phosphate low-melting glasses

    International Nuclear Information System (INIS)

    Menaa, Bouzid; Mizuno, Megumi; Takahashi, Masahide; Tokuda, Yomei; Yoko, Toshinobu

    2006-01-01

    We investigated the water durability of the inorganic-organic hybrid tin-silico-phosphate glasses Me 2 SiO-SnO-P 2 O 5 (Me designs the organic methyl group) doped with organic acids (salicylic acid (SA), tartaric acid (TA), citric acid (Canada) and butane tetracarboxylic acid (BTCA)) containing one or more of carboxylic groups per molecule. The structure, thermal properties and durability of the final glasses obtained via a non-aqueous acid-base reaction were discussed owing to the nature and the concentration of the acid added. 29 Si magic angle spinning (MAS) NMR and 31 P MAS NMR spectra, respectively, showed clearly a modification of the network in the host glass matrix of the Me 2 SiO-SnO-P 2 O 5 system. The polycondensation enhancement to form -P-O-Si-O-P- linkages (PSP) and the increase of the Q 2 unit (two bridging oxygens per phosphorus atom) over the Q 3 unit (three bridging oxygens per phosphorus atom) as a function of the acid in the order SA 2 SiO-SnO-P 2 O 5 matrix. In addition, this structural change is accompanied by a decrease of the coefficient of thermal expansion and an increase of the water durability of the glasses with the acids containing a large number of carboxylic groups per molecule. The presence of carboxylic groups of the acid acting as network modifier may retard the movement of water molecules through the glasses due to the steric hindrance strengthening the PSP connections in a chain-like structure

  11. Phosphate acquisition efficiency and phosphate starvation tolerance ...

    Indian Academy of Sciences (India)

    3Department of Genetics and Plant Breeding, College of Agriculture, Lembucherra, Tripura 799 ... vated in soil like red and lateritic or acid, with low soluble phosphate content. ..... activation of genes involved in the adaptation of Arabidopsis to.

  12. Orange and reddish-orange light emitting phosphors: Sm{sup 3+} and Sm{sup 3+}/Eu{sup 3+} doped zinc phosphate glasses

    Energy Technology Data Exchange (ETDEWEB)

    Meza-Rocha, A.N., E-mail: ameza@fis.cinvestav.mx [Departamento de Física, Universidad Autónoma Metropolitana-Iztapalapa, P.O. Box 55-534, 09340 México D.F., México (Mexico); Speghini, A. [Dipartimento di Biotecnologie, Universita di Verona and INSTM, UdR Verona, Strada Le Grazie 15, I-37314 Verona (Italy); IFAC CNR, Nello Carrara Institute of Applied Physics, MDF Lab, I-50019 Sesto Fiorentino, FI (Italy); Bettinelli, M. [Dipartimento di Biotecnologie, Universita di Verona and INSTM, UdR Verona, Strada Le Grazie 15, I-37314 Verona (Italy); Caldiño, U. [Departamento de Física, Universidad Autónoma Metropolitana-Iztapalapa, P.O. Box 55-534, 09340 México D.F., México (Mexico)

    2015-11-15

    A spectroscopy study of Sm{sup 3+} and Sm{sup 3+}/Eu{sup 3+} doped zinc phosphate glasses is performed through photoluminescence spectra and decay time profile measurements. Under Sm{sup 3+} excitation at 344 nm, the Sm{sup 3+} singly doped glass shows an orange global emission with x=0.579 and y=0.414 CIE1931 chromaticity coordinates, whereas the Sm{sup 3+}/Eu{sup 3+} co-doped sample exhibits orange overall emissions (x=0.581 and y=0.398, and x=0.595 and y=0.387) and reddish-orange overall emission (x=0.634 and y=0.355) upon excitations at 344, 360 and 393 nm, respectively. Such luminescence from the co-doped sample is originated by the simultaneous emission of Sm{sup 3+} and Eu{sup 3+}. Under Sm{sup 3+} excitation at 344 and 360 nm, the Eu{sup 3+} emission is sensitized and enhanced by Sm{sup 3+} through a non-radiative energy transfer process. The non-radiative nature was inferred from the shortening of the Sm{sup 3+} lifetime observed in the Sm{sup 3+}/Eu{sup 3+} co-doped sample. An analysis of the Sm{sup 3+} emission decay time profiles using the Inokuti–Hirayama model suggests that an electric quadrupole–quadrupole interaction into Sm–Eu clusters might dominate the energy transfer process, with an efficiency of 0.17. - Highlights: • Zinc phosphate glasses are optically activated with Sm{sup 3+}/Eu{sup 3+} (ZPOSmEu). • Non-radiative energy transfer Sm{sup 3+}→Eu{sup 3+} takes place in ZPOSmEu. • ZPOSmEu overall emission can be modulated with the excitation wavelength. • ZPOSmEu might be useful as orange/reddish-orange phosphor for UV-white LEDs.

  13. Na/Ca Intermixing around Silicate and Phosphate Groups in Bioactive Phosphosilicate Glasses Revealed by Heteronuclear Solid-State NMR and Molecular Dynamics Simulations.

    Science.gov (United States)

    Mathew, Renny; Stevensson, Baltzar; Edén, Mattias

    2015-04-30

    We characterize the intermixing of network-modifying Na(+)/Ca(2+) ions around the silicate (QSi(n)) and phosphate (QP(n)) tetrahedra in a series of 16 Na2O–CaO–SiO2–P2O5 glasses, whose P content and silicate network connectivity were varied independently. The set includes both bioactive and bioinactive compositions and also encompasses two soda-lime-silicate members devoid of P, as well as two CaO–SiO2 glasses and one Na2O–SiO2–P2O5 glass. The various Si/P↔Na/Ca contacts were probed by molecular dynamics (MD) simulations together with heteronuclear magic-angle-spinning (MAS) nuclear magnetic resonance (NMR) experimentation utilizing (23)Na{(31)P} and (23)Na{(29)Si} REDOR, as well as (31)P{ (23)Na} and (29)Si{(23)Na} REAPDOR. We introduce an approach for quantifying the extent of Na(+)/Ca(2+) ordering around a given QP(n) or QSi(n) group, encoded by the preference factor 0⩽ PM ⩽ 1 conveying the relative weights of a random cation intermixing (PM = 0) and complete preference/ordering (PM = 1) for one of the species M, which represents either Na(+) or Ca(2+). The MD-derived preference factors reveal phosphate and silicate species surrounded by Na(+)/Ca(2+) ions intermixed nearly randomly (PM ≲ 0.15), except for the QSi(4) and QSi(1) groups, which manifest more significant cation ordering with preference for Na+ and Ca2+, respectively. The overall weak preferences are essentially independent of the Si and P contents of the glass, whereas PM primarily correlates with the total amount of network modifiers: as the latter is increased, the Na/Ca distribution around the {QP(0), QSi(1), QSi(2)} groups with preference for Ca2(+ )tend to randomize (i.e., PCa decreases), while the PNa-values grow slightly for the {QP(1), QSi(3), QSi(4)} species already preferring coordination of Na. The set of experimental preference factors {PCa} for the orthophosphate (QP(0)) groups extracted from (31)P{(23)Na} REAPDOR NMR-derived M2(P–Na) dipolar second moments agrees

  14. The effect of electron irradiation on the structure and iron speciation in sodium aluminum (iron) phosphate glasses

    Energy Technology Data Exchange (ETDEWEB)

    Stefanovsky, S.V., E-mail: serge.stefanovsky@yandex.ru [Frumkin Institute of Physical Chemistry and Electrochemistry RAS (Russian Federation); Presniakov, I.A.; Sobolev, A.V.; Glazkova, I.S. [Lomonosov Moscow State University, Department of Chemistry (Russian Federation); Kadyko, M.I.; Stefanovsky, O.I. [Frumkin Institute of Physical Chemistry and Electrochemistry RAS (Russian Federation)

    2016-08-01

    The effect of 8 MeV electron irradiation on the structure of glasses in the series 40 Na{sub 2}O, (20-x) Al{sub 2}O{sub 3}, x Fe{sub 2}O{sub 3}, 40 P{sub 2}O{sub 5} (mol.%) and on the iron speciation in these samples was studied by FTIR and Mössbauer spectroscopic techniques. Irradiation up to a dose of 1.0 MGy has no appreciable effects on the character of the bonds within anionic motif of the glass network. Electron irradiation increases the fraction of aluminum in octahedral coordination. Iron in both unirradiated and irradiated glasses is present mainly as Fe(III) (60–75% of the total amount) in the glasses and partly as Fe(II) and the ratio of two forms remains constant up to a dose of 1.0 MGy.

  15. Characterization and spectroscopic studies of multi-component calcium zinc bismuth phosphate glass ceramics doped with iron ions

    Science.gov (United States)

    Kumar, A. Suneel; Narendrudu, T.; Suresh, S.; Ram, G. Chinna; Rao, M. V. Sambasiva; Tirupataiah, Ch.; Rao, D. Krishna

    2018-04-01

    Glass ceramics with the composition 10CaF2-20ZnO-(15-x)Bi2O3-55P2O5:x Fe2O3(0≤x≤2.5) were synthesized by melt-quenching technique and heat treatment. These glass ceramics were characterized by XRD and SEM. Spectroscopic studies such as optical absorption, EPR were also carried out on these glass ceramics. From the absorption spectra the observed bands around 438 and 660nm are the octahedral transitions of Fe3+ (d5) ions and another band at about 536 nm is the tetrahedral transition of Fe3+ (d5) ions. The absorption spectrum also consist of a band around 991 nm and is attributed to the octahedral transition of Fe2+ ions. The EPR spectra of the prepared glass ceramics have exhibited two resonance signals one at g1=4.32 and another signal at g2=2.008. The observed decrease in band gap energy up to 2 mol% Fe2O3 doped glass ceramics is an evidence for the change of environment around iron ions and ligands from more covalent to less covalent (ionic) and induces higher concentration of NBOs which causes the depolymerization of the glass ceramic network.

  16. Optical absorption, {sup 31}P NMR, and photoluminescence spectroscopy study of copper and tin co-doped barium–phosphate glasses

    Energy Technology Data Exchange (ETDEWEB)

    Jiménez, J.A., E-mail: jose.jimenez@unf.edu; Zhao, C.

    2014-10-15

    The optical and structural properties of 50P{sub 2}O{sub 5}:50BaO glasses prepared by melting have been investigated for additive concentrations of 10 and 1 mol% of CuO and SnO dopants. Absorption and photoluminescence spectroscopies were employed in the optical characterization, whereas structural properties were assessed by {sup 31}P nuclear magnetic resonance (NMR) spectroscopy. Residual Cu{sup 2+} was detectable by absorption spectroscopy for the highest concentration of CuO and SnO. More prominently, the optical data suggests contributions from both twofold-coordinated Sn centers and Cu{sup +} ions to light absorption and emission in the glasses. The luminescence depends strongly on excitation wavelength for the highest concentration of dopants where a blue–white emission is observed under short-wavelength excitation (e.g., 260 nm) largely due to tin, while an orange luminescence is exhibited for longer excitation wavelengths (e.g., 360 nm) essentially due to Cu{sup +} ions. On the other hand, dissimilar luminescent properties were observed in connection to Cu{sup +} ions for the lowest concentration studied, as the copper ions were preferentially excited in a narrower range at shorter wavelengths near tin centers absorption. The structural analyses revealed the glass matrix to be composed essentially of Q{sup 2} (two bridging oxygens) and Q{sup 1} (one bridging oxygen) phosphate tetrahedra. A slight increase in the Q{sup 1}/Q{sup 2} ratio reflected upon SnO doping alone suggests a major incorporation of tin into the glass network via P–O–Sn bonds, compatible with the 2-coordinated state attributed to the luminescent Sn centers. However, a significant increase in the Q{sup 1}/Q{sup 2} ratio was indicated with the incorporation of copper at the highest concentration, consistent with a key role of the metal ions as network modifiers. Thus, the change in Cu{sup +} optical properties concurs with different distributions of local environments around the

  17. Doping of low-T{sub g} phosphate glass with Al{sub 2}O{sub 3}, B{sub 2}O{sub 3} and SiO{sub 2}: Part I- effect on glass property and stability

    Energy Technology Data Exchange (ETDEWEB)

    Rajbhandari, P., E-mail: p.rajbhandari@sheffield.ac.uk [UCCS UMR-CNRS 8181, Universite de Lille1, Villeneuve d' Ascq (France); Montagne, L. [UCCS UMR-CNRS 8181, Universite de Lille1, Villeneuve d' Ascq (France); Tricot, G. [UCCS UMR-CNRS 8181, Universite de Lille1, Villeneuve d' Ascq (France); LASIR UMR-CNRS 8516, Universite de Lille1, Villeneuve d' Ascq (France)

    2016-11-01

    A zinc alkali pyrophosphate system 46.6ZnO-20Na{sub 2}O-33.5P{sub 2}O{sub 5} presenting low-T{sub g} (339 °C) and good thermal stability has been doped with (1–4) mol% of Al{sub 2}O{sub 3}, B{sub 2}O{sub 3} and SiO{sub 2} to improve the stability of the glass with a minimal increase in glass transition temperature (T{sub g}). XRD and 1D {sup 31}P solid state NMR were used to monitor the isothermal crystallization process occurring at 130 °C above T{sub g}. If the Al{sub 2}O{sub 3} and B{sub 2}O{sub 3} doping significantly improved thermal stability, this property was marginally affected by SiO{sub 2} doping. Viscosity measurements were performed to observe the crystallization effects induced by the doping. It is noteworthy that the T{sub g} values of all the doped compositions with improved stability presented in this work are below 400 °C. Raman spectroscopy, 1D {sup 31}P, {sup 27}Al, {sup 11}B and {sup 29}Si solid state NMR were carried out to determine the structural modifications and coordination states of the doping elements all along the composition line. - Highlights: • Low-Tg phosphate glasses doped with Al{sub 2}O{sub 3}, B{sub 2}O{sub 3} and SiO{sub 2} have been formulated. • Thermal stability of the glass has been improved significantly. • The structural modification induced by doping elements has been studied by employing solid state NMR technique.

  18. Study of the surface crystallization and resistance to dissolution of niobium phosphate glasses for nuclear waste immobilization; Estudo da cristalizacao superficial e da resistencia a dissolucao de vidros niobofosfatos visando a imobilizacao de rejeitos radioativos

    Energy Technology Data Exchange (ETDEWEB)

    Vieira, Heveline

    2008-07-01

    The surface crystallization and the dissolution rate of three phosphate glass compositions containing different amounts of niobium oxide were studied. The glasses were named Nb30, Nb37, and Nb44 according to the nominal content of niobium oxide in the glass composition. The three compositions were evaluated keeping the P{sub 2}O{sub 5}/K{sub 2}O ratio constant and varying the amount of Nb{sub 2}O{sub 5}. These glasses were produced by melting appropriate chemical compounds at 1500 deg C for 0.5 hour. The crystalline phases which were nucleated on the glass surface after heat treatment were determined by X-ray diffraction. The crystalline structures depend on the amount of niobium oxide in the glass composition. The crystal morphologies were observed by using an optical microscope, and their characteristics are specific for each kind of crystalline phase. The crystal growth rate and the surface nuclei density were determined for each glass composition, and they depend on each crystalline phase nucleated on the surface. From the differential thermal analysis curves it was determined that the Nb44 glass containing 46.5 mol por cent of niobium oxide is the most thermally stable against crystallization when compared to the Nb30 and Nb37 glasses. According to the activation energies determined for crystal growth on the surface of each glass type, the Nb44 glass can also be considered the most resistant one against crystallization. The dissolution rate for the Nb44 glass after 14 days immersed in an aqueous solution with pH equals to 7 at 90 deg C is the lowest (9.0 x 10{sup -7} g. cm{sup -2} . day{sup -1}) when compared to the other two glass compositions. The dissolution rates in acidic and neutral solutions of all studied glasses meet the international standards for materials which can be used in the immobilization of nuclear wastes. (author)

  19. Retentive [correction of Preventive] efficacy of glass ionomer, zinc phosphate and zinc polycarboxylate luting cements in preformed stainless steel crowns: a comparative clinical study.

    Science.gov (United States)

    Khinda, V I S; Grewal, N

    2002-06-01

    This study was undertaken to assess the efficacy of three luting cements, namely, glass ionomer, zinc phosphate and zinc polycarboxylate in retainng the preformed stainless steel crowns in-vivo. Twenty subjects, with an indication for restoration of three primary molars with stainless steel crowns, were selected. Sixty teeth were taken up for the study, and twenty crowns were cemented with each of the three luting cements. After an eight month follow up the crowns were assessed for their presence/ absence or "rocking". Statistical analysis was done using Chi-square test. The results have shown no significant difference in retentivity of stainless steel crowns with the use of either of the three luting agents.

  20. Nanoshaving and Nanografting of Water Soluble Polymers on Glass and Silicon Dioxide Surfaces with Applications to DNA Localization

    Science.gov (United States)

    Davis, Brian; Conley, Hiram; Ochoa, Rosie; Hurd, Katie; Linford, Matthew R.; Davis, Robert C.

    2008-10-01

    Chemical surface patterning at the nanoscale is a critical component of chemically directed assembly of nanoscale devices or sensitive biological molecules onto surfaces. Here we present a scanning probe lithography technique that allows for patterning of aqueous polymers on glass or silicon dioxide surfaces. The surfaces were functionalized by covalently bonding a silane monolayer with a known surface charge to either a glass slide or a silicon wafer. A polymer layer less then 2 nm in thickness was electrostatically bound to the silane layer, passivating the functionalized surface. An Atomic Force Microscope (AFM) probe was used to remove a portion of the polymer layer, exposing the functional silane layer underneath. Employing this method we made chemically active submicron regions. These regions were backfilled with a fluorescent polymer and Lambda-DNA. Chemical differentiation was verified through tapping mode AFM and optical fluorescent microscopy. Lines with a pitch as small as 20nm were observed with AFM height and phase mode data.

  1. Sulphate solubility and sulphate diffusion in oxide glasses: implications for the containment of sulphate-bearing nuclear wastes; Solubilite et cinetiques de diffusion des sulfates dans differents verres d'oxydes: application au conditionnement des dechets nucleaires sulfates

    Energy Technology Data Exchange (ETDEWEB)

    Lenoir, M.

    2009-09-15

    The thesis deals with sulphate solubility and sulphate diffusion in oxide glasses, in order to control sulphate incorporation and sulphate volatilization in nuclear waste glasses. It was conducted on simplified compositions, in the SiO{sub 2}-B{sub 2}O{sub 3}-R{sub 2}O (R = Li, Na, K, Cs), SiO{sub 2}-B{sub 2}O{sub 3}-BaO and V{sub 2}O{sub 5}-B{sub 2}O{sub 3}-BaO systems. These compositions allowed us to study the influence of the nature of network-modifying ions (Li{sup +}, Na{sup +}, K{sup +}, Cs{sup +} or Ba{sup 2+}) and also of former elements (Si, B, V), on structure and properties of glasses. Sulphate volatility is studied in sodium borosilicate melts using an innovative technique of sulphate quantitation with Raman spectroscopy. This technique is useful to obtain kinetic curves of sulphate volatilization. The establishment of a model to fit these curves leads to the determination of diffusion coefficients of sulphate. These diffusion coefficients can thus be compared to diffusion coefficients of other species, determined by other techniques and presented in the literature. They are also linked to diffusion coefficients in relation with the viscosity of the melts. Concerning sulphate solubility in glasses, it depends on glass composition and on the nature of sulphate incorporated. Sulphate incorporation in alkali borosilicate glasses leads to the formation of a sulphate layer floating on top of the melt. Sulphate incorporation in barium borosilicate and boro-vanadate glasses leads to the crystallization of sulphate species inside the vitreous matrix. Moreover, sulphate solubility is higher in these glasses than in alkali borosilicates. Finally, exchanges between cations present in glasses and cations present in the sulphate phase are also studied. (author)

  2. In Vitro Comparison of Zinc Phosphate and Glass Ionomers Ability to Inhibit Decalcification under and Adjacent to Orthodontic Bands.

    Science.gov (United States)

    1985-08-01

    confer the ability to leach fluoride ions into the surrounding tooth enamel . Kidd 3 7 using an artifical caries tec- hnique with a diffusion controlled...5 - Enamel Changes Scoring System- 1. NONE: No color change evident 2. MILD: Slight change in enamel color 3.MODERATE: Definate whitening of enamel ...to adhere to stainless steel and to tooth enamel with a chemical bond 51 . Zinc phosphate, on the other hand, does not chemically adhere to enamel or

  3. Enhanced 1.53 μm emission of Er{sup 3+} ions in phosphate glass via energy transfer from Cu{sup +} ions

    Energy Technology Data Exchange (ETDEWEB)

    Jiménez, José A., E-mail: jose.jimenez@unf.edu [Department of Chemistry, University of North Florida, Jacksonville, Florida 32224 (United States); Sendova, Mariana [Optical Spectroscopy and Nano-Materials Lab, New College of Florida, Sarasota, Florida 34243 (United States)

    2014-07-21

    Optimizing the efficiency of Er{sup 3+} emission in the near-infrared telecommunication window in glass matrices is currently a subject of great interest in photonics research. In this work, Cu{sup +} ions are shown to be successfully stabilized at a high concentration in Er-containing phosphate glass by a single-step melt-quench method, and demonstrated to transfer energy to Er{sup 3+} thereby enhancing the near-infrared emission about 15 times. The spectroscopic data indicate an energy conversion process where Cu{sup +} ions first absorb photons broadly around 360 nm and subsequently transfer energy from the Stokes-shifted emitting states to resonant Er{sup 3+} absorption transitions in the visible. Consequently, the Er{sup 3+} electronic excited states decay and the {sup 4}I{sub 3/2} metastable state is populated, leading to the enhanced emission at 1.53 μm. Monovalent copper ions are thus recognized as sensitizers of Er{sup 3+} ions, suggesting the potential of Cu{sup +} co-doping for applications in the telecommunications, solar cells, and solid-state lasing realizable under broad band near-ultraviolet optical pumping.

  4. Theoretical studies of the spin Hamiltonian parameters and local distortions for Cu{sup 2+} in alkaline earth lead zinc phosphate glasses

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Bo-Kun; Yuan, Zi-Yi; Liu, Zi-Xuan; Jiang, Shi-Xin; Liu, Zheng; Yao, Zi-Jian [University of Electronic Science and Technology of China, Chengdu (China). School of Yingcai Honors; Wu, Shao-Yi; Teng, Bao-Hua; Wu, Ming-He [University of Electronic Science and Technology of China, Chengdu (China). Dept. of Applied Physics

    2016-11-01

    The spin Hamiltonian parameters and local structures are theoretically studied for Cu{sup 2+}-doped alkaline earth lead zinc phosphate (RPPZ, R=Mg, Ca, Sr, and Ba) glasses based on the high-order perturbation calculations for a tetragonally elongated octahedral 3d{sup 9} cluster. The relative elongation ratios are found to be ρ ∼ 3.2%, 4.4%, 4.6%, and 3.3% for R=Mg, Ca, Sr, and Ba, respectively, because of the Jahn-Teller effect. The whole decreasing crystal-field strength Dq and orbital reduction factor k from Mg to Sr are ascribed to the weakening electrostatic coulombic interactions and the increasing probability of productivity of nonbridge oxygen (and hence increasing Cu{sup 2+}-O{sup 2-} electron cloud admixtures) under PbO addition, respectively, with increasing alkali earth ionic radius. The anomalies (the largest Dq and the next highest k among the systems) for R=Ba are attributed to the cross linkage of this large cation in the network. The overall increasing order (Mg≤Baglasses containing copper dopants.

  5. 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

  6. Investigating the influence of Na+ and Sr2+ on the structure and solubility of SiO2-TiO2-CaO-Na2O/SrO bioactive glass.

    Science.gov (United States)

    Li, Y; Placek, L M; Coughlan, A; Laffir, F R; Pradhan, D; Mellott, N P; Wren, A W

    2015-02-01

    This study was conducted to determine the influence that network modifiers, sodium (Na+) and strontium (Sr2+), have on the solubility of a SiO2-TiO2-CaO-Na2O/SrO bioactive glass. Glass characterization determined each composition had a similar structure, i.e. bridging to non-bridging oxygen ratio determined by X-ray photoelectron spectroscopy. Magic angle spinning nuclear magnetic resonance (MAS-NMR) confirmed structural similarities as each glass presented spectral shifts between -84 and -85 ppm. Differential thermal analysis and hardness testing revealed higher glass transition temperatures (Tg 591-760 °C) and hardness values (2.4-6.1 GPa) for the Sr2+ containing glasses. Additionally the Sr2+ (~250 mg/L) containing glasses displayed much lower ion release rates than the Na+ (~1,200 mg/L) containing glass analogues. With the reduction in ion release there was an associated reduction in solution pH. Cytotoxicity and cell adhesion studies were conducted using MC3T3 Osteoblasts. Each glass did not significantly reduce cell numbers and osteoblasts were found to adhere to each glass surface.

  7. New greenish-yellow and yellowish-green emitting glass phosphors: Tb{sup 3+}/Eu{sup 3+} and Ce{sup 3+}/Tb{sup 3+}/Eu{sup 3+} in zinc phosphate glasses

    Energy Technology Data Exchange (ETDEWEB)

    Caldino, U., E-mail: cald@xanum.uam.mx [Departamento de Fisica, Universidad Autonoma Metropolitana-Iztapalapa, P.O. Box 55-534, 09340 Mexico D.F. (Mexico); Alvarez, E. [Departamento de Fisica, Universidad de Sonora (UNISON), Boulevard Luis Encinas y Rosales s/n, Hermosillo, Sonora 83000, Mexico (Mexico); Speghini, A. [Dipartimento di Biotecnologie, Universita di Verona, and INSTM, UdR Verona, Strada Le Grazie 15, I-37314 Verona (Italy); IFAC CNR, Nello Carrara Institute of Applied Physics, MDF Lab, I-50019 Sesto Fiorentino, FI (Italy); Bettinelli, M. [Dipartimento di Biotecnologie, Universita di Verona, and INSTM, UdR Verona, Strada Le Grazie 15, I-37314 Verona (Italy)

    2013-03-15

    A spectroscopic investigation of zinc phosphate glasses activated with Eu{sup 3+}, Tb{sup 3+}/Eu{sup 3+} and Ce{sup 3+}/Tb{sup 3+}/Eu{sup 3+} ions is performed through photoluminescence spectra and decay time measurements. Greenish-yellow light emission, with x=0.42 and y=0.50 CIE1931 chromaticity coordinates, is obtained in the 5.0% Tb(PO{sub 3}){sub 3}-2.0% Eu(PO{sub 3}){sub 3} codoped zinc phosphate glass upon Tb{sup 3+} excitation at 340 nm. Such greenish-yellow luminescence is generated mainly by the {sup 5}D{sub 4}{yields}{sup 7}F{sub 6,5} and {sup 5}D{sub 0}{yields}{sup 7}F{sub 1,2} emissions of Tb{sup 3+} and Eu{sup 3+}, respectively, europium being sensitized by terbium through a non-radiative energy transfer. By codoping with 0.1 Ce(PO{sub 3}){sub 3} in addition to Tb{sup 3+}/Eu{sup 3+} yellowish-green light emission with CIE1931 chromaticity coordinates, x=0.33 and y=0.48, is achieved through non-radiative energy transfer from Ce{sup 3+} to Tb{sup 3+} and from Ce{sup 3+} via Tb{sup 3+} to Eu{sup 3+} upon 280 nm excitation (peak emission wavelength of AlGaN-based LEDs). - Highlights: Black-Right-Pointing-Pointer Zn(PO{sub 3}){sub 2} glasses are optically activated with Tb{sup 3+}/Eu{sup 3+} (ZPO5Tb2Eu) and Ce{sup 3+}/Eu{sup 3+}/Tb{sup 3+} (ZPOCe5Tb2Eu). Black-Right-Pointing-Pointer Non-radiative energy transfer Tb{sup 3+}{yields}Eu{sup 3+} takes place in ZPO5Tb2Eu. Black-Right-Pointing-Pointer Greenish-yellow light is generated by ZPO5Tb2Eu pumped with 340 nm-UV light. Black-Right-Pointing-Pointer Non-radiative energy transfer Ce{sup 3+}{yields}Tb{sup 3+} and Ce{sup 3+}{yields}Eu{sup 3+} via Tb{sup 3+} takes place in ZPOCe5Tb2Eu. Black-Right-Pointing-Pointer Yellowish-green light is generated by ZPOCe5Tb2Eu pumped with 280 nm-UV light (AlGaN-LEDs).

  8. Soluble DPP-4 up-regulates toll-like receptors and augments inflammatory reactions, which are ameliorated by vildagliptin or mannose-6-phosphate.

    Science.gov (United States)

    Lee, Dong-Sung; Lee, Eun-Sol; Alam, Md Morshedul; Jang, Jun-Hyeog; Lee, Ho-Sub; Oh, Hyuncheol; Kim, Youn-Chul; Manzoor, Zahid; Koh, Young-Sang; Kang, Dae-Gil; Lee, Dae Ho

    2016-02-01

    Studies have shown that dipeptidyl peptidase-4 (DPP-4) inhibitors have anti-inflammatory effects. Soluble DPP-4 (sDPP-4) has been considered as an adipokine of which actions need to be further characterized. We investigated the pro-inflammatory actions of sDPP-4 and the anti-inflammatory effects of DPP-4 inhibition, using vildagliptin, as an enzymatic inhibitor, and mannose-6-phosphate (M6P) as a competitive binding inhibitor. In lipopolysaccharide (LPS)-stimulated RAW264.7 cells, vildagliptin suppressed the increased expression of inducible nitric oxide synthase (iNOS) and phosphorylated JNK (pJNK), activation of the NF-κB pathway, and the resultant NO and proinflammatory cytokine production. Although sDPP-4 alone did not affect the protein level of iNOS or pJNK or the production of NO in RAW264.7 cells, it did amplify iNOS expression, NO responses, and proinflammatory cytokine production in LPS-stimulated RAW264 cells. As a probable mechanism, we found that sDPP-4 caused dose-dependent increases in the expression levels of toll-like receptor 4 (TLR4) and TLR2 in RAW264.7 cells, and that these alterations were inhibited by vildagliptin, M6P, or bisindolylmaleimide II, a protein kinase C inhibitor. Either vildagliptin or M6P suppressed iNOS expression and NO and cytokine production in LPS+DPP-4-co-stimulated macrophages, while combined treatment of the co-stimulated cells with both agents had increased anti-inflammatory effects compared with either treatment alone. Intravenous injection of sDPP-4 to C57BL/6J mice increased the expression of both TLRs in kidney and white adipose tissues. Our findings suggest that sDPP-4 enhances inflammatory actions via TLR pathway, while DPP-4 inhibition with either an enzymatic or binding inhibitor has anti-inflammatory effects. Copyright © 2015 Elsevier Inc. All rights reserved.

  9. Kinetic study of Tb/sup 3 +/(/sup 5/D/sub 3/) luminescence in phosphate glasses

    Energy Technology Data Exchange (ETDEWEB)

    Anisimov, V.A.; Dmitryuk, A.V.; Karapetyan, G.O.

    1986-01-01

    This paper presents precise determinations of the kinetics of terbium luminescence over a broad dynamic range, in order to refine the mechanism of concentration quenching of the Tb/sup 3 +/(/sup 5/D/sub 3/) luminescence in glasses. After establishing the mechanism of Tb/sup 3 +/(/sup 5/D/sub 3/) luminescence quenching by the iteration method, the authors determine the value of the parameter for an arbitrary concentration of the activator. Results of this study show that the mechanism of concentration quenching of luminescence is static dipole-dipole interaction of terbium ions.

  10. Thermo-optical properties of Nd{sup 3+} doped phosphate glass determined by thermal lens and lifetime measurements

    Energy Technology Data Exchange (ETDEWEB)

    Martins, V.M. [Instituto de Física, Universidade Federal de Uberlândia, CEP38408-902 Uberlandia, Minas Gerais (Brazil); CIMAP – Centre de recherche sur les Ions, les Matériaux et la Photonique UMR 6252 CEA-CNRS-ENSICAEN-Université de Caen, 14050 Caen Cedex 4 (France); Messias, D.N., E-mail: dnmessias@infis.ufu.br [Instituto de Física, Universidade Federal de Uberlândia, CEP38408-902 Uberlandia, Minas Gerais (Brazil); Doualan, J.L.; Braud, A.; Camy, P. [CIMAP – Centre de recherche sur les Ions, les Matériaux et la Photonique UMR 6252 CEA-CNRS-ENSICAEN-Université de Caen, 14050 Caen Cedex 4 (France); Dantas, N.O. [Instituto de Física, Universidade Federal de Uberlândia, CEP38408-902 Uberlandia, Minas Gerais (Brazil); CIMAP – Centre de recherche sur les Ions, les Matériaux et la Photonique UMR 6252 CEA-CNRS-ENSICAEN-Université de Caen, 14050 Caen Cedex 4 (France); Instituto de Física de São Carlos, Universidade de São Paulo, USP, CEP 13560-970 São Carlos, SP (Brazil); Catunda, T. [Instituto de Física de São Carlos, Universidade de São Paulo, USP, CEP 13560-970 São Carlos, SP (Brazil); Pilla, V.; Andrade, A.A. [Instituto de Física, Universidade Federal de Uberlândia, CEP38408-902 Uberlandia, Minas Gerais (Brazil); and others

    2015-06-15

    In this paper the Normalized Lifetime Thermal Lens technique was applied to a set of Nd-doped phosphate samples in order to obtain its thermal and optical properties. Moreover, radiative emission properties were obtained by the Judd–Ofelt theory. The luminescence quantum efficiency obtained by both methods agreed very well, indicating that this thermal lens approach can be used in more complex systems where no radiative property is available. - Highlights: • Normalized Lifetime Thermal Lens was used to investigate Nd-doped samples. • Experimental setup and data analysis are simpler than in conventional techniques. • Luminescence quantum yield agrees with that obtained through standard techniques. • This approach, to obtain the quantum yield, can be extended to more complex systems.

  11. Ce+3-and Tb+3-luminescence in glasses. Ce+3-activated bulk silica and silica thin films. An α-particle detector based on a Ce+3-activated silica thin film. A Ce+3-Tb+3-energy transfer in a high melting point phosphate glass

    International Nuclear Information System (INIS)

    Heindl, R.; Loriers, J.; Sella, J.C.; Robert, A.

    1984-07-01

    While many Ce +3 -activated glasses of different type emit strongly under UV (253,7 nm) and β-ray excitation, only the commercial silicate glass NE 905 shows an useful emission when exposed to α-particles. Only phosphate glasses have give the green Tb +3 -emission, when doped by it, under UV and α and β radiation. Sputtered films of Ce +3 -activated silica have appropriate luminescence properties, adherence to the substrate and a perfect chemical resistance to hot nitric acid. An α-particle detector has been built which has permitted the quantitative detection of plutonium in the presence of other radiative ions

  12. Effect of pH values on surface modification and solubility of phosphate bioglass-ceramics in the CaO-P 2O 5-Na 2O-SrO-ZnO system

    Science.gov (United States)

    Li, Xudong; Cai, Shu; Zhang, Wenjuang; Xu, Guohua; Zhou, Wei

    2009-08-01

    The bioactive glass-ceramics in the CaO-P 2O 5-Na 2O-SrO-ZnO system were synthesized by the sol-gel technique, and then chemically treated at different pH values to study the solubility and surface modification. Samples sintered at 650 °C for 4 h consisted of the crystalline phase β-Ca 2P 2O 7 and the glass matrix. After soaking in the solution at pH 1.0, the residual glass matrix on the surface appeared entirely dissolved and no new phase could be detected. Whereas at pH 3.0, web-like layer exhibiting peaks corresponding to CaP 2O 6 was formed and covered the entire surface of the sample. When conducted at pH 10.0, only part of the glass matrix was dissolved and a new phase Ca 4P 6O 19 was precipitated, forming the petaline layer. The chemical treatment can easily change the surface morphologies and phase composition of this bioactive glass-ceramics. The higher level of surface roughness resulting from the new-formed layer would improve the interface bonding and benefit for cell adhesion.

  13. Development Of Glass Matrices For HLW Radioactive Wastes

    International Nuclear Information System (INIS)

    Jantzen, C.

    2010-01-01

    Vitrification is currently the most widely used technology for the treatment of high level radioactive wastes (HLW) throughout the world. Most of the nations that have generated HLW are immobilizing in either borosilicate glass or phosphate glass. One of the primary reasons that glass has become the most widely used immobilization media is the relative simplicity of the vitrification process, e.g. melt waste plus glass forming frit additives and cast. A second reason that glass has become widely used for HLW is that the short range order (SRO) and medium range order (MRO) found in glass atomistically bonds the radionuclides and governs the melt properties such as viscosity, resistivity, sulphate solubility. The molecular structure of glass controls contaminant/radionuclide release by establishing the distribution of ion exchange sites, hydrolysis sites, and the access of water to those sites. The molecular structure is flexible and hence accounts for the flexibility of glass formulations to waste variability. Nuclear waste glasses melt between 1050-1150 C which minimizes the volatility of radioactive components such as Tc 99 , Cs 137 , and I 129 . Nuclear waste glasses have good long term stability including irradiation resistance. Process control models based on the molecular structure of glass have been mechanistically derived and have been demonstrated to be accurate enough to control the world's largest HLW Joule heated ceramic melter in the US since 1996 at 95% confidence.

  14. DEVELOPMENT OF GLASS MATRICES FOR HLW RADIOACTIVE WASTES

    Energy Technology Data Exchange (ETDEWEB)

    Jantzen, C.

    2010-03-18

    Vitrification is currently the most widely used technology for the treatment of high level radioactive wastes (HLW) throughout the world. Most of the nations that have generated HLW are immobilizing in either borosilicate glass or phosphate glass. One of the primary reasons that glass has become the most widely used immobilization media is the relative simplicity of the vitrification process, e.g. melt waste plus glass forming frit additives and cast. A second reason that glass has become widely used for HLW is that the short range order (SRO) and medium range order (MRO) found in glass atomistically bonds the radionuclides and governs the melt properties such as viscosity, resistivity, sulphate solubility. The molecular structure of glass controls contaminant/radionuclide release by establishing the distribution of ion exchange sites, hydrolysis sites, and the access of water to those sites. The molecular structure is flexible and hence accounts for the flexibility of glass formulations to waste variability. Nuclear waste glasses melt between 1050-1150 C which minimizes the volatility of radioactive components such as Tc{sup 99}, Cs{sup 137}, and I{sup 129}. Nuclear waste glasses have good long term stability including irradiation resistance. Process control models based on the molecular structure of glass have been mechanistically derived and have been demonstrated to be accurate enough to control the world's largest HLW Joule heated ceramic melter in the US since 1996 at 95% confidence.

  15. Effects of the addition of casein phosphopeptide-amorphous calcium phosphate (CPP-ACP) on mechanical properties of luting and lining glass ionomer cement

    Science.gov (United States)

    Heravi, Farzin; Bagheri, Hossein; Rangrazi, Abdolrasoul; Mojtaba Zebarjad, Seyed

    2016-07-01

    Recently, the addition of casein phosphopeptide-amorphous calcium phosphate (CPP-ACP) into glass ionomer cements (GICs) has attracted interest due to its remineralization of teeth and its antibacterial effects. However, it should be investigated to ensure that the incorporation of CPP-ACP does not have significant adverse effects on its mechanical properties. The purpose of this study was to evaluate the effects of the addition of CPP-ACP on the mechanical properties of luting and lining GIC. The first step was to synthesize the CPP-ACP. Then the CPP-ACP at concentrations of 1%, 1.56% and 2% of CPP-ACP was added into a luting and lining GIC. GIC without CPP-ACP was used as a control group. The results revealed that the incorporation of CPP-ACP up to 1.56%(w/w) increased the flexural strength (29%), diametral tensile strength (36%) and microhardness (18%), followed by a reduction in these mechanical properties at 2%(w/w) CPP-ACP. The wear rate was significantly decreased (23%) in 1.56%(w/w) concentration of CPP-ACP and it was increased in 2%(w/w). Accordingly, the addition of 1.56%(w/w) CPP-ACP into luting and lining GIC had no adverse effect on the mechanical properties of luting and lining GIC and could be used in clinical practice.

  16. Use of glass-ceramic materials for the fixation of radioactive wastes

    International Nuclear Information System (INIS)

    Minaev, A.A.; Oziraner, S.N.; Prokhorova, N.P.

    1979-01-01

    This paper is concerned with the study of the crystallization of phosphate and silicate glasses. It was shown that temperature and time of storage influence considerably the crystallization of glasses and that crystallization very often increases their rates of leaching to a great extent. However, there are glasses in which crystallization does not result in leaching rate increase. It seems reasonable to use these materials for the fixation of radioactive wastes. The main reasons for the increase in the leaching rate during crystallization are the formation of porosity and soluble crystal phases

  17. Phosphate solubilization and multiple plant growth promoting ...

    African Journals Online (AJOL)

    Phosphate solubilizing efficiencies of the strains were analyzed using different insoluble phosphorus sources and the results show that most isolates released a substantial amount of soluble phosphate from tricalcium phosphate, rock phosphate and bone meal. Screening for multiple plant growth promoting attributes ...

  18. Assessment of in situ immobilization of Lead (Pb) and Arsenic (As) in contaminated soils with phosphate and iron: solubility and bioaccessibility

    NARCIS (Netherlands)

    Cui, Y.S.; Du, X.; Weng, L.P.; Riemsdijk, van W.H.

    2010-01-01

    The effect of in situ immobilization of lead (Pb) and arsenic (As) in soil with respectively phosphate and iron is well recognized. However, studies on combined Pb and As-contaminated soil are fewer, and assessment of the effectiveness of the immobilization on mobility and bioaccessibility is also

  19. Effect of boron oxide addition on fibre drawing, mechanical properties and dissolution behaviour of phosphate-based glass fibres with fixed 40, 45 and 50 mol% P2O5.

    Science.gov (United States)

    Sharmin, Nusrat; Parsons, Andrew J; Rudd, Chris D; Ahmed, Ifty

    2014-11-01

    Previous studies investigating manufacture of phosphate-based glass fibres from glasses fixed with P2O5 content less than 50 mol% showed that continuous manufacture without breakage was very difficult. In this study, nine phosphate-based glass formulations from the system P2O5-CaO-Na2O-MgO-B2O3 were prepared with P2O5 contents fixed at 40, 45 and 50 mol%, where Na2O was replaced by 5 and 10 mol% B2O3 and MgO and CaO were fixed to 24 and 16 mol%, respectively. The effect of B2O3 addition on the fibre drawing, fibre mechanical properties and dissolution behaviour was investigated. It was found that addition of 5 and 10 mol% B2O3 enabled successful drawing of continuous fibres from glasses with phosphate (P2O5) contents fixed at 40, 45 and 50 mol%. The mechanical properties of the fibres were found to significantly increase with increasing B2O3 content. The highest tensile strength (1200 ± 130 MPa) was recorded for 45P2O5-16CaO-5Na2O-24MgO-10B2O3 glass fibres. The fibres were annealed, and a comparison of the mechanical properties and mode of degradation of annealed and non-annealed fibres were investigated. A decrease in tensile strength and an increase in tensile modulus were observed for the annealed fibres. An assessment of the change in mechanical properties of both the annealed and non-annealed fibres was performed in phosphate-buffered saline (PBS) at 37℃ for 28 and 60 days, respectively. Initial loss of mechanical properties due to annealing was found to be recovered with degradation. The B2O3-containing glass fibres were found to degrade at a much slower rate as compared to the non-B2O3-containing fibres. Both annealed and non-annealed fibres exhibited a peeling effect of the fibre's outer layer during degradation. © The Author(s) 2014 Reprints and permissions: sagepub.co.uk/journalsPermissions.nav.

  20. Down-shifting by energy transfer in Tb{sup 3+}/Dy{sup 3+} co-doped zinc phosphate glasses

    Energy Technology Data Exchange (ETDEWEB)

    Caldiño, U., E-mail: cald@xanum.uam.mx [Departamento de Física, Universidad Autónoma Metropolitana-Iztapalapa, P.O. Box 55-534, México, D.F. 09340 (Mexico); Muñoz H, G.; Camarillo, I. [Departamento de Física, Universidad Autónoma Metropolitana-Iztapalapa, P.O. Box 55-534, México, D.F. 09340 (Mexico); Speghini, A. [Dipartimento di Biotecnologie, Università di Verona, and INSTM, UdR Verona, Strada Le Grazie 15, I-37314 Verona (Italy); IFAC CNR, Nello Carrara Institute of Applied Physics, MDF Lab, I-50019 Sesto Fiorentino, FI (Italy); Bettinelli, M. [Dipartimento di Biotecnologie, Università di Verona, and INSTM, UdR Verona, Strada Le Grazie 15, I-37314 Verona (Italy)

    2015-05-15

    An optical spectroscopy investigation of zinc phosphate glasses activated with Tb{sup 3+}/Dy{sup 3+} ions is carried out through photoluminescence spectra and decay time measurements. The emission color can be adjusted from yellow–green light, with CIE1931 chromaticity coordinates (0.36,0.44), toward the white light region (0.35,0.39) by decreasing the Tb{sup 3+} content from 1.0 to 0.1 mol% of Tb(PO{sub 3}){sub 3} upon Dy{sup 3+} excitation at 423 nm. Such visible region luminescence is generated by {sup 5}D{sub 4}→{sup 7}F{sub 5} and {sup 5}D{sub 4}→{sup 7}F{sub 3} emissions of Tb{sup 3+} in addition to {sup 4}I{sub 15/2}→{sup 6}H{sub 15/2}, {sup 4}F{sub 9/2}→{sup 6}H{sub 15/2}, {sup 4}F{sub 9/2}→{sup 6}H{sub 13/2} and {sup 4}F{sub 9/2}→{sup 6}H{sub 11/2} emissions of Dy{sup 3+}, so that Tb{sup 3+} emission is sensitized by Dy{sup 3+} through a non-radiative resonant energy transfer. A dominant {sup 5}D{sub 4}→{sup 7}F{sub 5} green emission is observed in detriment of the {sup 5}D{sub 3}→{sup 7}F{sub J} blue emissions upon 282 nm excitation, as well as an extended excitation range (280–500 nm), due to multiple Dy{sup 3+} and Tb{sup 3+} transitions, which might contribute to enhance the spectral response of solar photovoltaic cells by down-shifting of the incident solar spectrum. - Highlights: • Zn(PO{sub 3}){sub 2} glasses are optically activated with Tb{sup 3+}/Dy{sup 3+} (ZPTbDy). • Non-radiative resonant energy transfer takes place between Tb{sup 3+} and Dy{sup 3+}. • Luminescence can be adjusted from yellow–green light toward the white light region. • ZPTbDy phosphor exhibits spectroscopic properties for photovoltaic applications.

  1. Effects of silver adsorbed on fumed silica, silver phosphate glass, bentonite organomodified with silver and titanium dioxide in aquatic indicator organisms.

    Science.gov (United States)

    Tomacheski, Daiane; Pittol, Michele; Simões, Douglas Naue; Ribeiro, Vanda Ferreira; Santana, Ruth Marlene Campomanes

    2017-06-01

    In order to reduce the level of transmission of diseases caused by bacteria and fungi, the development of antimicrobial additives for use in personal care, hygiene products, clothing and others has increased. Many of these additives are based on metals such as silver and titanium. The disposal of these products in the environment has raised concerns pertaining to their potential harmfulness for beneficial organisms. The objective of this study was to evaluate the influence of the shape, surface chemistry, size and carrier of three additives containing silver and one with titanium dioxide (TiO 2 ) on microcrustacean survival. Daphnia magna was used as a bioindicator for acute exposure test in suspensions from 0.0001 to 10,000ppm. Ceriodaphnia dubia was used for chronic test in TiO 2 suspensions from 0.001 to 100ppm. D. magna populations presented high susceptibility to all silver based additives, with 100% mortality after 24hr of exposure. A different result was found in the acute experiments containing TiO 2 suspensions, with mortality rates only after 48hr of incubation. Even on acute and chronic tests, TiO 2 did not reach a linear concentration-response versus mortality, with 1ppm being more toxic than 10,000ppm on acute test and 0.001 more toxic than 0.01ppm on chronic assay. Silver based material toxicity was attributed to silver itself, and had no relation to either form (nano or ion) or carrier (silica, phosphate glass or bentonite). TiO 2 demonstrated to have a low acute toxicity against D. magna. Copyright © 2016. Published by Elsevier B.V.

  2. Aluminum elution and precipitation in glass vials: effect of pH and buffer species.

    Science.gov (United States)

    Ogawa, Toru; Miyajima, Makoto; Wakiyama, Naoki; Terada, Katsuhide

    2015-02-01

    Inorganic extractables from glass vials may cause particle formation in the drug solution. In this study, the ability of eluting Al ion from borosilicate glass vials, and tendencies of precipitation containing Al were investigated using various pHs of phosphate, citrate, acetate and histidine buffer. Through heating, all of the buffers showed that Si and Al were eluted from glass vials in ratios almost the same as the composition of borosilicate glass, and the amounts of Al and Si from various buffer solutions at pH 7 were in the following order: citrate > phosphate > acetate > histidine. In addition, during storage after heating, the Al concentration at certain pHs of phosphate and acetate buffer solution decreased, suggesting the formation of particles containing Al. In citrate buffer, Al did not decrease in spite of the high elution amount. Considering that the solubility profile of aluminum oxide and the Al eluting profile of borosilicate glass were different, it is speculated that Al ion may be forced to leach into the buffer solution according to Si elution on the surface of glass vials. When Al ions were added to the buffer solutions, phosphate, acetate and histidine buffer showed a decrease of Al concentration during storage at a neutral range of pHs, indicating the formation of particles containing Al. In conclusion, it is suggested that phosphate buffer solution has higher possibility of forming particles containing Al than other buffer solutions.

  3. Nonlinear acoustic properties of the ternary (La sub 2 O sub 3) sub x (Sm sub 2 O sub 3) sub y (P sub 2 O sub 5) sub (1-x-y) phosphate glasses

    International Nuclear Information System (INIS)

    Senin, H.B.; Sidek, H.A.A.; Saunders, G.A.

    1994-01-01

    From measurements of changes in transit time of 10 MHz of ultrasonic wave as a function of temperature and hydrostatic pressure, the linear and non-linear acoustic properties of the ternary (La sub 2 O sub 3) sub x (Sm sub 2 O sub 3) sub y (P sub 2 O sub 5) sub (1-x-y) glasses with compositions near to that corresponding to the metaphosphate have been determined. For each glass the second order elastic stiffness tensor components C sub ijs (SOEC) continue to increase down to 10K in a manner consistent with phonons interactions with two level systems. Measurements of the effects of hydrostatic pressure on the ultrasonic wave velocities have been used to determine the hydrostatic pressure derivatives (dC sub ij/dP) sub T,P=0 of the SOEC and (dB0 sup s)/dP) sub T,P=0 of the bulk modulus B0 sup s at room temperature (293K). For the ternary (La sub 2 O sub 3) sub x (Sm sub 2 O sub 3) sub y (P sub 2 O sub 5) sub (1-x-y) glasses, (dC sub 11/dP), (dC sub 44/dP), and (dBo/dP), are small but positives; these glasses stiffen under pressure. The elastic behaviour of these ternary glasses lies intermediate between those of (Sm sub 2 O sub 3)(P sub 2 O sub 5) sub (1-x) and (La sub 2 O sub 3) sub y (P sub 2 O sub 5) sub (1-x-y) glasses. Replacement of the Sm sup 3+ by La sup 3+ in the ternary phosphate glasses negates the acoustic mode softening. Possible sources of the different effects of La sub 3+ and Sm sub 3+ modifiers on the nonlinear acoustic properties of metaphosphate glasses are discussed

  4. The effects of crystallization and residual glass on the chemical durability of iron phosphate waste forms containing 40 wt% of a high MoO3 Collins-CLT waste

    Science.gov (United States)

    Hsu, Jen-Hsien; Bai, Jincheng; Kim, Cheol-Woon; Brow, Richard K.; Szabo, Joe; Zervos, Adam

    2018-03-01

    The effects of cooling rate on the chemical durability of iron phosphate waste forms containing up to 40 wt% of a high MoO3 Collins-CLT waste simulant were determined at 90 °C using the product consistency test (PCT). The waste form, designated 40wt%-5, meets appropriate Department of Energy (DOE) standards when rapidly quenched from the melt (as-cast) and after slow cooling following the CCC (canister centerline cooling)-protocol, although the quenched glass is more durable. The analysis of samples from the vapor hydration test (VHT) and the aqueous corrosion test (differential recession test) reveals that rare earth orthophosphate (monazite) and Zr-pyrophosphate crystals that form on cooling are more durable than the residual glass in the 40wt%-5 waste form. The residual glass in the CCC-treated samples has a greater average phosphate chain length and a lower Fe/P ratio, and those contribute to its faster corrosion kinetics.

  5. 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.

  6. 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)

  7. Hydrogen permeation resistant phosphate coatings

    International Nuclear Information System (INIS)

    McGuire, J.C.

    1979-01-01

    A method for reducing hydrogen diffusion through metal wherein the metal is coated with a phosphate-radical-containing, phosphate-glass-forming material on at least one surface thereof. The coating is then heated to at least 350 0 C to form a phosphate glass. This method is especially applicable to nuclear reactors to minimize tritium diffusion. The coating is preferably formed with a solution of phosphoric acid which may also contain compounds such as MnSO 4 , SiO 2 and Na 2 Cr 2 0 7 . (author)

  8. Hydrogen permeation resistant phosphate coatings

    International Nuclear Information System (INIS)

    McGuire, J.C.

    1979-01-01

    A method for reducing hydrogen diffusion through metal is described. The metal is coated with a phosphate-radical-containing, phosphate-glass-forming material on at least one surface. The coating is then heated to at least 350 0 C to form a phosphate glass. This method is especially applicable to nuclear reactors to minimize tritium diffusion. The coating is preferably formed with a solution of phosphoric acid which may also contain compounds such as MnSO 4 , SiO 2 and Na 2 Cr 2 O 7 . (author)

  9. INTERACTION OF SILVER MOLECULAR CLUSTERS, INTRODUCED BY LOW-TEMPERATURE ION EXCHANGE METHOD, WITH NANOPARTICLES OF CdS IN FLUORINE PHOSPHATE GLASSES

    Directory of Open Access Journals (Sweden)

    N. D. Grazhdanov

    2015-09-01

    Full Text Available Glasses with metallic and semi-conductive nano-particles appear to be perspective non-linear and luminescent materials of photonics. It was shown in theory that composite optical materials containing semi-conductive CdS-core with Ag shell (or vice versa are optimal for enhancement of non-linear Kerr effect. Interaction of such an ensemble of particles leads to the forming of Ag island structures on the CdS particle, and formation of acanthite Ag2S on the two phases border (CdS-Ag is minimal. In glasses synthesis of CdS quantum dots occurred due to thermal treatment close to glass transition temperature; introduction of silver was realized by low-temperature ion exchange (LIE. The main object of this work is investigation of Ag+ -LIE effect on the growth of CdS nano-particles. Two glasses were explored in this work: without CdS (glass 1 and with CdS (glass 2, processed by LIE at the temperature of 320°С for 10, 20 and 30 minutes and subsequent heat treatment at temperatures of 410°С and 420°С. In case of glass 1, intensive luminescence appears as a result of LIE, and subsequent heat treatment results in surface resonance at λ=410 nm. In case of glass 2, absorbance spectra change appears that is specific for formation of acanthite and weak luminescence shifting to long-wavelength region (from 550 to 700 nm as a result of applying LIE and heat treatment. It indicates the growth of CdS quantum dots. Experiment has shown that quantum efficiency increases to 70% for glass 2 containing CdS quantum dots without LIE, while glass that contains silver shows steep decrease of quantum efficiency to 0%. That decrease is caused by formation of acanthite Ag2S on the surface of CdS quantum dot.

  10. Occurrence and functioning of phosphate solubilizing ...

    African Journals Online (AJOL)

    Occurrence and functioning of phosphate solubilizing microorganisms from oil palm tree ( Elaeis guineensis ) rhizosphere in Cameroon. ... While the use of soluble mineral phosphate fertilizers is the obvious best means to combat phosphate ... in order to improve agricultural production, using low inputs technology. Isolates ...

  11. 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

  12. Molecular glasses for nuclear waste encapsulation

    International Nuclear Information System (INIS)

    Ropp, R.C.

    1982-01-01

    The use of a molecular glass based upon a polymerized phosphate of aluminum (PAP), indium or gallium overcomes all of the prior objections to use of glass as a high-level nuclear waste (HLW) encapsulation agent. This HLW glass product could not be made to devitrify, dissolved all of the oxides found in calcine, including the difficultly soluble ones, did not form microcrystallites in the melt or subsequent glass-casting, and possessed a hydrolytic etching rate to boiling water even lower than that of HLW-ZBS glass. A precursor compound, M(H 2 PO 4 ) 3 , is prepared, where M is a trivalent metal selected from the group consisting of aluminum, indium and gallium. The impurity level is carefully controlled so as not to exceed 300 ppm total. The precursor crystals may be washed to remove excess phosphoric acid as desired. HLW is added to the crystals and the mixture is then heated at a controlled heating rate to induce solid state polymerization and to form a melt at 1350 degrees C in which the HLW oxides dissolve rapidly

  13. Effectiveness of phosphate fertilizers of diffrent water solubilities in relation to soil phophorus adsorption Adsorção de fósforo pelo solo e eficiência de fertilizantes fosfatados com diferente solubilidade em água

    Directory of Open Access Journals (Sweden)

    Luís Ignácio Prochnow

    2006-08-01

    Full Text Available Phosphate fertilizers should match soil attributes to enhance agronomic effectiveness and recovery by plants. The purpose of this study was to test the agronomic effectiveness of P sources varying in water solubility on two soils differing widely in P adsorption capacity (PAC. Soils selected for the study were Oxisols with very low available P and presenting low and high PAC (Ox-LPAC and Ox-HPAC, respectively. Both were limed to pH 5.4 in a greenhouse study conducted utilizing corn as the test crop. Treatments consisted of the two soils interacting with five P sources (monocalcium phosphate - MCP, low-grade single superphosphate - LG-SSP, multimagnesium phosphate - MMP, Arad phosphate rock - PR and a P impurity in triple superphosphate - H14, and four rates of P (12.5, 25.0, 50.0 and 100.0 mg kg-1. A control with no P was added for each soil. The treatments were arranged as blocks with three replicates. Plants were harvested 45 d after germination. Dry-matter yield and P uptake were measured and the relative agronomic effectiveness (RAE compared with MCP as the standard. When applied in low rates of P (12.5 and 25.0 mg kg-1 the RAE of the alternative sources was higher in the soil with high PAC (45, 66, 39 and 65% in the Ox-HPAC for the LG-SSP, MMP, PR and H14, respectively, as opposed to 24, 40, 14 and 47% in the Ox-LPAC. Results suggest that sources of P with low water solubility can be agronomically more effective in soils with high PAC.Fertilizantes fosfatados devem ser aplicados tendo em vista os atributos do solo. Este estudo foi conduzido para testar fontes de P, distintas quanto à solubilidade, na eficiência agronômica em solos com diferença marcante na capacidade de adsorção de P (CAP. Foram selecionados dois Latossolos com teor muito baixo de P e apresentando baixa e elevada CAP (Lat-BCAP e Lat-ECAP, respectivamente. Ambos foram corrigidos para pH 5,4 e utilizados em experimento em casa-de-vegetação com milho. Os tratamentos

  14. Disposition of actinides released from high-level waste glass

    International Nuclear Information System (INIS)

    Ebert, W.L.; Bates, J.K.; Buck, E.C.; Gong, M.; Wolf, S.F.

    1994-01-01

    The disposition of actinide elements released from high-level waste glasses into a tuff groundwater in laboratory tests at 90 degrees C at various glass surface area/leachant volume ratios (S/V) between dissolved, suspended, and sorbed fractions has been measured. While the maximum release of actinides is controlled by the corrosion rate of the glass matrix, their solubility and sorption behavior affects the amounts present in potentially mobile phases. Actinide solubilities are affected by the solution pH and the presence of complexants released from the glass, such as sulfate, phosphate, and chloride, radiolytic products, such as nitrate and nitrite, and carbonate. Sorption onto inorganic colloids formed during lass corrosion may increase the amounts of actinides in solution, although subsequent sedimentation of these colloids under static conditions leads to a significant reduction in the amount of actinides in solution. The solution chemistry and observed actinide behavior depend on the S/V of the test. Tests at high S/V lead to higher pH values, greater complexant concentrations, and generate colloids more quickly than tests at low S/V. The S/V also affects the rate of glass corrosion

  15. Matrix tablets: the effect of hydroxypropyl methylcellulose/anhydrous dibasic calcium phosphate ratio on the release rate of a water-soluble drug through the gastrointestinal tract I. In vitro tests.

    Science.gov (United States)

    Mamani, Pseidy L; Ruiz-Caro, Roberto; Veiga, María D

    2012-12-01

    Different hydroxypropyl methylcellulose (HPMC)/anhydrous dibasic calcium phosphate (ADCP) matrix tablets have been developed aiming to evaluate the influence of both components ratio in the control release of a water-soluble drug (theophylline). In order to characterise the matrix tablets, swelling, buoyancy and dissolution studies have been carried out in different aqueous media (demineralised water, progressive pH medium, simulated gastric fluid, simulated intestinal fluid and simulated colonic fluid). The HPMC/ADCP ratio has turned out to be the determinant in the matrix behaviour: the HPMC characteristic swelling behaviour was modulated, in some cases, by the ADCP characteristic acidic dissolution. When the HPMC/ADCP ratio was ≥0.69, buoyancy, continuous swelling and low theophylline dissolution rate from the matrices (H1, H2 and H3) were observed in all dissolution media. Consequently, these formulations could be adequate as gastro-retentive drug delivery systems. Additionally, HPMC/ADCP ratio ≤0.11 (H5 and H6) induces a pH-dependent drug release which could be applied to design control drug release enteric formulations (with a suitable enteric coating). Finally, a HPMC/ADCP ratio between 0.11 and 0.69 (H4) yield a gastrointestinal controlled drug release, due to its time-dependent buoyancy (7 h) and a total drug delivery in 17 h in simulated colonic fluid.

  16. Effect of B{sub 2}O{sub 3}/P{sub 2}O{sub 5} substitution on the properties and structure of tin boro-phosphate glasses

    Energy Technology Data Exchange (ETDEWEB)

    Saitoh, Akira, E-mail: asaito@ehime-u.ac.jp [Graduate School of Science and Engineering, Ehime University, Matsuyama, 3 Bunkyo-cho (Japan); Tricot, Grégory [LASIR UMR-CNRS 8516, Université de Lille 1, Villeneuve d' Ascq 59655 (France); UCCS UMR-CNRS 8181, Université de Lille 1, Villeneuve d' Ascq 59655 (France); Rajbhandari, Prashant [UCCS UMR-CNRS 8181, Université de Lille 1, Villeneuve d' Ascq 59655 (France); Anan, Shoji; Takebe, Hiromichi [Graduate School of Science and Engineering, Ehime University, Matsuyama, 3 Bunkyo-cho (Japan)

    2015-01-15

    Effect of B{sub 2}O{sub 3}/P{sub 2}O{sub 5} substitution on the properties and structure of the ternary 67SnO–(33–x)P{sub 2}O{sub 5}–xB{sub 2}O{sub 3} composition line (from x = 0–33 mol%) are examined in this contribution. We show that density and glass transition temperature increase while molar volume and thermal expansion coefficient decrease with increasing B{sub 2}O{sub 3} concentration. Density and thermal properties experience an original three-domain evolution with rapid (region I: 0 ≤ x < 5), substantial (II: 5 < x ≤ 15), and moderate (III: 15 < x ≤ 33) increase. In order to explain this unconventional behaviour, the glass structure has been investigated using high magnetic field 1 dimensional {sup 31}P and {sup 11}B MAS–NMR, micro-Raman and infrared spectroscopies. {sup 11}B MAS–NMR experiments allow to (i) monitor the 3- and 4-fold coordinated borate species proportion and (ii) highlight the presence of unreported 4-fold coordinated species in the region (III). Finally, it is shown that substitution of P{sub 2}O{sub 5} by B{sub 2}O{sub 3} induces an alteration of the dimeric phosphate network and formation of mixed anion structure that consists of Q{sup 0} phosphate units, 3- and 4-fold coordinated borate units and their combinations. - Highlights: • We examined B{sub 2}O{sub 3}/P{sub 2}O{sub 5} substitution effect on the ternary SnO–P{sub 2}O{sub 5}–B{sub 2}O{sub 3} glasses. • We show a three-domains evolution for density and thermal properties. • The structure was investigated by {sup 31}P and {sup 11}B NMR, Raman and IR spectroscopies. • 3 and 4-folded borate species and unreported 4-folded species are revealed. • Mixed anion structure consists of Q{sup 0} phosphate unit and 3- and 4-folded borate units.

  17. Analyses of uranium in some phosphate commercial products

    International Nuclear Information System (INIS)

    Kamel, N.H.M.; Sohsah, M.; Mohammad, H.M.; Sadek, M.

    2005-01-01

    The raw materials used in manufacturing of phosphate fertilizer products were derived from rocks. Rocks contain a remarkable of natural radioactivity. Uranium and phosphorous were originally initiated at the same time of the initiated rocks. The purpose of this research is to investigate solubility of uranium phosphate species at the phosphate fertilizer samples, samples including; raw phosphate material, single super phosphates (SSP) granules and powdered, triple super phosphates (TSP) and phosphogypsum samples were obtained from Abu-Zabal factory in Egypt. Solubility of uranium phosphate species was estimated. It was found that, less than half of the uranium phosphate species are soluble in water. The soluble uranium may be enter into the food chains by plant. Therefore, restriction should be done in order to limit contamination of land and the public

  18. Role of Al coordination in barium phosphate glasses on the emission features of Ho{sup 3+} ion in the visible and IR spectral ranges

    Energy Technology Data Exchange (ETDEWEB)

    Satyanarayana, T.; Kalpana, T.; Ravi Kumar, V. [Department of Physics, Acharya Nagarjuna University-Nuzvid Campus, Nuzvid-521 201, A.P. (India); Veeraiah, N., E-mail: nvr8@rediffmail.co [Department of Physics, Acharya Nagarjuna University-Nuzvid Campus, Nuzvid-521 201, A.P. (India)

    2010-03-15

    The glasses of the composition (39-x)BaO-xAl{sub 2}O{sub 3}-60P{sub 2}O{sub 5}:1.0Ho{sub 2}O{sub 3} (in mol%) with x value ranging from 1.0 to 4.0 have been synthesized. The IR spectral studies of these glasses have indicated that there is a gradual transformation of Al{sup 3+} ions from tetrahedral to octahedral with increase in the concentration of Al{sub 2}O{sub 3} up to 3.0 mol%. Optical absorption and fluorescence spectra (in the visible and NIR regions) of these glasses have been recorded at room temperature. The Judd-Ofelt theory could successfully be applied to characterize the absorption and luminescence spectra of Ho{sup 3+} ions in these glasses. From the luminescence spectra, various radiative properties like transition probability A, branching ratio beta{sub r}, the radiative lifetime tau{sub r} and emission cross-section sigma{sup E} for various emission levels of these glasses have been evaluated. The radiative lifetime of the {sup 5}S{sub 2}->{sup 5}I{sub 8} (green emission) transition has also been measured. The variations observed in these parameters have been discussed in the light of varying co-ordinations (tetrahedral and octahedral positions) of Al{sup 3+} ions in the glass network. The influence of hydroxyl groups on the luminescence efficiency of the transition {sup 5}S{sub 2}->{sup 5}I{sub 8} has also been discussed. Finally the optimum concentration of Al{sub 2}O{sub 3} for getting maximum luminescence output has also been identified and reported.

  19. Uranium solubility and solubility controls in selected Needle's Eye groundwaters

    International Nuclear Information System (INIS)

    Falck, W.E.; Hooker, P.J.

    1991-01-01

    The solubility control of uranium in selected groundwater samples from the cliff and sediments at the Needle's Eye natural analogue site is investigated using the speciation code PHREEQE and the CHEMVAL thermodynamic database (release 3). Alkali-earth bearing uranyl carbonate secondary minerals are likely to exert influence on the solubility . Other candidates are UO 2 and arsenates, depending on the prevailing redox conditions. In the absence of literature data, solubility products for important arsenates have been estimated from analogy with other arsenates and phosphates. Phosphates themselves are unlikely to exert control owing to their comparatively high solubilities. The influence of seawater flooding into the sediments is also discussed. The importance of uranyl arsenates in the retardation of uranium in shallow sediments has been demonstrated in theory, but there are some significant gaps in the thermodynamic databases used. (author)

  20. X-ray absorption spectroscopy on phosphoric-salt pellets. Determination of the geometric and electronic structure of metal-oxide doped sodium-phosphate glasses

    International Nuclear Information System (INIS)

    Brendebach, B.

    2004-02-01

    Sodium metaphosphate glasses doped with transition metal oxides show characteristic colors. X-ray absorption spectroscopy (XAS) investigations provide information whether the coloration stems from different electronic transitions or changes in the geometrical structure of the glasses. Even though the violet color of MnO y -doped glasses is considered as an evidence for Mn 3+ -ions, Mn K-XAS reveals that the majority of the manganese ions are in the oxidation state +II and have a mixed coordination of four and six oxygen atoms, respectively. The oxygen coordination around the nickel ions in NiO-doped glasses with different metall oxide concentrations is always six. The change of color from citreous to auburn with increasing nickel oxide content is attributed to a systematic change in the bonding characteristic from mainly ionic-like to a small but significant contribution of covalent-like bonding. Analysis of higher coordination shells provides no indication of the formation of metal oxide clusters. (orig.)

  1. The red-shift of ultraviolet spectra and the relation to optical basicity of Ce-doped alkali rare-earth phosphate glasses

    Czech Academy of Sciences Publication Activity Database

    Chen, G.; Baccaro, S.; Nikl, Martin; Cecilia, A.; Du, Y. Y.; Mihóková, Eva

    2004-01-01

    Roč. 87, č. 7 (2004), s. 1378-1380 ISSN 0002-7820 R&D Projects: GA MŠk ME 621 Institutional research plan: CEZ:AV0Z1010914 Keywords : scintillation glass * Ce 3+ * luminescence * absorption Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 1.710, year: 2004

  2. Development Of High Waste-Loading HLW Glasses For High Bismuth Phosphate Wastes, VSL-12R2550-1, Rev 0

    International Nuclear Information System (INIS)

    Kruger, A. A.; Pegg, Ian L.; Gan, Hao; Kot, Wing K.

    2012-01-01

    This report presents results from tests with new glass formulations that have been developed for several high Bi-P HLW compositions that are expected to be processed at the WTP that have not been tested previously. WTP HLW feed compositions were reviewed to select waste batches that are high in Bi-P and that are reasonably distinct from the Bi-limited waste that has been tested previously. Three such high Bi-P HLW compositions were selected for this work. The focus of the present work was to determine whether the same type of issues as seen in previous work with high-Bi HLW will be seen in HLW with different concentrations of Bi, P and Cr and also whether similar glass formulation development approaches would be successful in mitigating these issues. New glass compositions were developed for each of the three representative Bi-P HLW wastes and characterized with respect to key processing and product quality properties and, in particular, those relating to crystallization and foaming tendency

  3. Development Of High Waste-Loading HLW Glasses For High Bismuth Phosphate Wastes, VSL-12R2550-1, Rev 0

    Energy Technology Data Exchange (ETDEWEB)

    Kruger, A. A. [Department of Energy, Office of River Protection, Richland, Washington (United States); Pegg, Ian L. [The Catholic University of America, Washington, DC (United States); Gan, Hao [The Catholic University of America, Washington, DC (United States); Kot, Wing K. [The Catholic University of America, Washington, DC (United States)

    2012-12-13

    This report presents results from tests with new glass formulations that have been developed for several high Bi-P HLW compositions that are expected to be processed at the WTP that have not been tested previously. WTP HLW feed compositions were reviewed to select waste batches that are high in Bi-P and that are reasonably distinct from the Bi-limited waste that has been tested previously. Three such high Bi-P HLW compositions were selected for this work. The focus of the present work was to determine whether the same type of issues as seen in previous work with high-Bi HLW will be seen in HLW with different concentrations of Bi, P and Cr and also whether similar glass formulation development approaches would be successful in mitigating these issues. New glass compositions were developed for each of the three representative Bi-P HLW wastes and characterized with respect to key processing and product quality properties and, in particular, those relating to crystallization and foaming tendency.

  4. Solubility limit of Mn{sup 2+} ions in Zn{sub 1−x}Mn{sub x}Te nanocrystals grown within an ultraviolet-transparent glass template

    Energy Technology Data Exchange (ETDEWEB)

    Silva, Alessandra dos Santos, E-mail: alemestrado@gmail.com [Universidade Federal de Uberlândia, Laboratório de Novos Materiais Isolantes e Semicondutores (LNMIS), Instituto de Física (Brazil); Silva, Sebastião William da; Morais, Paulo Cesar de [Universidade de Brasília, Núcleo de Física Aplicada, Instituto de Física (Brazil); Dantas, Noelio Oliveira [Universidade Federal de Uberlândia, Laboratório de Novos Materiais Isolantes e Semicondutores (LNMIS), Instituto de Física (Brazil)

    2016-05-15

    This paper reports on the synthesis of Zn{sub 1−x}Mn{sub x}Te nanocrystals (NCs) (with 0 ≤ x ≤ 0.800) within a PZABP glass system (P{sub 2}O{sub 5}–ZnO–Al{sub 2}O{sub 3}–BaO–PbO) using the fusion method. The as-grown samples were investigated by optical absorption measurements, atomic force microscopy, X-ray diffraction, and Raman spectroscopy. The mean radius of the as-produced NCs (around R ≈ 2.2 nm) was well below the exciton Bohr radius of the bulk ZnTe (5.2 nm). All the characterization techniques employed in this report confirmed the successful inclusion of Mn{sup 2+} ions in the ZnTe-based NCs (Zn{sub 1−x}Mn{sub x}Te NCs) up to the nominal solubility limit of x = 0.100. Above this solubility limit (around x = 0.100), one can observe the formation of MnO and α-MnO{sub 2} NCs, since the nucleation rate for the formation of these NCs is greater than that of Zn{sub 1−x}Mn{sub x}Te NCs, at high x concentrations.Graphical abstract.

  5. Energy transfer processes in Yb{sup 3+}-Tm{sup 3+} co-doped sodium alumino-phosphate glasses with improved 1.8 {mu}m emission

    Energy Technology Data Exchange (ETDEWEB)

    Camargo, Andrea S S de; Terra, Idelma A A; Nunes, Luiz Antonio de O; Li, M Siu [Instituto de Fisica de Sao Carlos, Universidade de Sao Paulo, 13560-970, Sao Carlos-SP (Brazil)], E-mail: andreasc@ifsc.usp.br

    2008-06-25

    Sodium alumino-phosphate glasses co-doped with Yb{sup 3+} and Tm{sup 3+} ions have been prepared with notably low OH{sup -} content, and characterized from the viewpoint of their spectroscopic properties. In these glasses, Yb{sup 3+} acts as an efficient sensitizer of excitation energy at 0.98 {mu}m-which can be provided by high power and low cost diode lasers, and subsequently undergoes non-resonant energy transfer to Tm{sup 3+} ions ({sup 2}F{sub 5/2}, {sup 3}H{sub 6} {yields} {sup 2}F{sub 7/2}, {sup 3}H{sub 5}). Through this process, the emitting level {sup 3}F{sub 4} is rapidly populated, generating improved emission at 1.8 {mu}m ({sup 3}F{sub 4} {yields} {sup 3}H{sub 6}). In order to guarantee the efficiency of such favorable energy transfer, energy losses via multiphonon decay, Yb-Yb radiative trapping, and non-radiative transfer to OH{sup -} groups were evaluated, and minimized when possible. The dipole-dipole energy transfer microscopic parameters corresponding to Yb{sup 3+} {yields} Tm{sup 3+}, Yb{sup 3+} {yields} Yb{sup 3+} and Tm{sup 3+} {yields} Tm{sup 3+} transfers, calculated by the Foerster-Dexter model, are C{sub Yb-Tm} = 2.9 x 10{sup -40} cm{sup 6} s{sup -1}, C{sub Yb-Yb} = 42 x 10{sup -40} cm{sup 6} s{sup -1} and C{sub Tm-Tm} = 43 x 10{sup -40} cm{sup 6} s{sup -1}, respectively.

  6. Lithium-free silver-activated alkali-alkaline earth-aluminium phosphate glass for radiophotoluminescence dosimetry with decreased pre-dose and increased chemical resistance. Lithiumfreies, silberaktiviertes Alkali-Erdalkali-Aluminium-Phosphatglas fuer die Radiophotolumineszenzdosimetrie mit verringertem Vordosiswert und erhoehter chemischer Resistenz

    Energy Technology Data Exchange (ETDEWEB)

    Jahn, W.; Schumann, W.

    1980-07-24

    The silver activated phosphate glass (metaphosphate glass) is free of lithium and exhibits an improved chemical resistance, a constant sensitivity, as well as a predose value of only about 265 mRad. It was made by melting 23.9 wt.% NaPO, 24.4 wt.% Mg(PO), 48.2 wt.% Al (PO) and 3.5 wt.% AgPO at a temperature of 1250 C in a ceramic crucible, cleared of bubbles at 1450 C and then cooled slowly.

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

    Science.gov (United States)

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

    2016-02-22

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

  8. Physico-chemical characterization of Ogun and Sokoto phosphate ...

    African Journals Online (AJOL)

    Gypsum, calcite and lime were associated with both rock phosphates indicating their liming potential in the soil. ORP was more soluble in water, probably because it ... fertilizers and direct application in crop production. Keywords: Phosphorus, apatite, crop production, fertilizer, Ogun rock phosphate, Sokoto rock phosphate ...

  9. Solubility of Meloxicam in Mixed Solvent Systems | Babu | Ethiopian ...

    African Journals Online (AJOL)

    The solubility of meloxicam is higher in phosphate buffer (pH 7.4) compared to water, probably due to ionization of the drug. The solubility of meloxicam is marginally enhanced in surfactant systems (Tween 80 and Brij 35) at concentrations higher than cmc, proving the micellar solubilization. Meloxicam solubility studies in ...

  10. 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.

  11. Phosphate Salts

    Science.gov (United States)

    ... body. They are involved in cell structure, energy transport and storage, vitamin function, and numerous other processes ... Phosphate-containing foods and beverages include cola, wine, beer, whole grain cereals, nuts, dairy products and some ...

  12. Compositional effects on the formation of a calcium phosphate layer and the response of osteoblast-like cells on polymer-bioactive glass composites.

    Science.gov (United States)

    Lu, Helen H; Tang, Amy; Oh, Seong Cheol; Spalazzi, Jeffrey P; Dionisio, Kathie

    2005-11-01

    Biodegradable polymer-ceramic composites are attractive systems for bone tissue engineering applications. These composites have the combined advantages of the component phases, as well as the inherent ease in optimization where desired material properties can be tailored in a well-controlled manner. This study focuses on the optimization of a polylactide-co-glycolide (PLAGA) and 45S5 bioactive glass (BG) composite for bone tissue engineering. The first objective is to examine the effects of composition or overall BG content on the formation of a Ca-P layer on the PLAGA-BG composite. It is expected that with increasing BG content (0%, 10%, 25%, 50% by weight), the required incubation time in a simulated body fluid (SBF) for the composite to form a detectable surface Ca-P layer will decrease. Both the kinetics and the chemistry will be determined using SEM+EDAX, FTIR, and mu-CT methods. Solution phosphorous and calcium concentrations will also be measured. The second objective of the study is to determine the effects of BG content on the maturation of osteoblast-like cells on the PLAGA-BG composite. It is hypothesized that mineralization will increase with increasing BG content, and the composite will support the proliferation and differentiation of osteoblasts. Specifically, cell proliferation, alkaline phosphatase activity and mineralization will be monitored as a function of BG content (0%, 10%, 50% by weight) and culturing time. It was found that the kinetics of Ca-P layer formation and the resulting Ca-P chemistry were dependent on BG content. The response of human osteoblast-like cells to the PLAGA-BG composite was also a function of BG content. The 10% and 25% BG composite supported greater osteoblast growth and differentiation compared to the 50% BG group. The results of this study suggest that there is a threshold BG content which is optimal for osteoblast growth, and the interactions between PLAGA and BG may modulate the kinetics of Ca-P formation and the

  13. Translocation of metal phosphate via the phosphate inorganic transport system of Escherichia coli

    NARCIS (Netherlands)

    van Veen, H.W; Abee, T.; Kortstee, G.J J; Konings, W.N; Zehnder, A.J B

    1994-01-01

    P-i transport via the phosphate inorganic transport system (Pit) of Escherichia coil was studied in natural and artificial membranes. P-i uptake via Pit is dependent on the presence of divalent cations, like Mg2+, Ca2+, Co2+, or Mn2+, which form a soluble, neutral metal phosphate (MeHPO(4)) complex.

  14. Proton Environments in Biomimetic Calcium Phosphates Formed from Mesoporous Bioactive CaO-SiO2-P2O5 Glasses in Vitro: Insights from Solid-State NMR.

    Science.gov (United States)

    Mathew, Renny; Turdean-Ionescu, Claudia; Yu, Yang; Stevensson, Baltzar; Izquierdo-Barba, Isabel; García, Ana; Arcos, Daniel; Vallet-Regí, María; Edén, Mattias

    2017-06-22

    When exposed to body fluids, mesoporous bioactive glasses (MBGs) of the CaO-SiO 2 -P 2 O 5 system develop a bone-bonding surface layer that initially consists of amorphous calcium phosphate (ACP), which transforms into hydroxy-carbonate apatite (HCA) with a very similar composition as bone/dentin mineral. Information from various 1 H-based solid-state nuclear magnetic resonance (NMR) experiments was combined to elucidate the evolution of the proton speciations both at the MBG surface and within each ACP/HCA constituent of the biomimetic phosphate layer formed when each of three MBGs with distinct Ca, Si, and P contents was immersed in a simulated body fluid (SBF) for variable periods between 15 min and 30 days. Directly excited magic-angle-spinning (MAS) 1 H NMR spectra mainly reflect the MBG component, whose surface is rich in water and silanol (SiOH) moieties. Double-quantum-single-quantum correlation 1 H NMR experimentation at fast MAS revealed their interatomic proximities. The comparatively minor H species of each ACP and HCA component were probed selectively by heteronuclear 1 H- 31 P NMR experimentation. The initially prevailing ACP phase comprises H 2 O and "nonapatitic" HPO 4 2- /PO 4 3- groups, whereas for prolonged MBG soaking over days, a well-progressed ACP → HCA transformation was evidenced by a dominating O 1 H resonance from HCA. We show that 1 H-detected 1 H → 31 P cross-polarization NMR is markedly more sensitive than utilizing powder X-ray diffraction or 31 P NMR for detecting the onset of HCA formation, notably so for P-bearing (M)BGs. In relation to the long-standing controversy as to whether bone mineral comprises ACP and/or forms via an ACP precursor, we discuss a recently accepted structural core-shell picture of both synthetic and biological HCA, highlighting the close relationship between the disordered surface layer and ACP.

  15. Removal of phosphate from solution by adsorption and precipitation of calcium phosphate onto monohydrocalcite.

    Science.gov (United States)

    Yagi, Shintaro; Fukushi, Keisuke

    2012-10-15

    The sorption behavior and mechanism of phosphate on monohydrocalcite (CaCO(3)·H(2)O: MHC) were examined using batch sorption experiments as a function of phosphate concentrations, ionic strengths, temperatures, and reaction times. The mode of PO(4) sorption is divisible into three processes depending on the phosphate loading. At low phosphate concentrations, phosphate is removed by coprecipitation of phosphate during the transformation of MHC to calcite. The sorption mode at the low-to-moderate phosphate concentrations is most likely an adsorption process because the sorption isotherm at the conditions can be fitted reasonably with the Langmuir equation. The rapid sorption kinetics at the conditions is also consistent with the adsorption reaction. The adsorption of phosphate on MHC depends strongly on ionic strength, but slightly on temperature. The maximum adsorption capacities of MHC obtained from the regression of the experimental data to the Langmuir equation are higher than those reported for stable calcium carbonate (calcite or aragonite) in any conditions. At high phosphate concentrations, the amount of sorption deviates from the Langmuir isotherm, which can fit the low-to-moderate phosphate concentrations. Speciation-saturation analyses of the reacted solutions at the conditions indicated that the solution compositions which deviate from the Langmuir equation are supersaturated with respect to a certain calcium phosphate. The obtained calcium phosphate is most likely amorphous calcium phosphate (Ca(3)(PO(4))(2)·xH(2)O). The formation of the calcium phosphate depends strongly on ionic strength, temperature, and reaction times. The solubility of MHC is higher than calcite and aragonite because of its metastability. Therefore, the higher solubility of MHC facilitates the formation of the calcium phosphates more than with calcite and aragonite. Copyright © 2012 Elsevier Inc. All rights reserved.

  16. 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.

  17. Role of VAM on growth and phosphorus nutrition of maize with low soluble phosphate fertilization Efecto de la infestación con micorrizas vesiculo arbusculares (VAM en plantas de Zea mays fertilizadas con dosis bajas de fósforo

    Directory of Open Access Journals (Sweden)

    Amitava Rakshit

    2010-01-01

    Full Text Available The effect of vesicular arbuscular mycorrhizal (VAM infection on growth and P nutrition in Maize (Zea mays, cv.DDH hybrid were assessed in Oxisol pot experiment. Maize was grown inoculated with spores of VAM fungi Glomus mosseae or non-inoculated. Low soluble ferrous phosphate (FePO4.4H2O was added to the mycorrhized and non-micrrohized maized. The dry weight of mycorrhized plants with added phosphate (P were higher than in mycorrhized plants without added P or non-mycorrhized plants with added P. The amount of P in the soil samples from pots with mycorrhizal plants fertilized with P was evidently smaller than those in samples also fertilized non-mycorrhizal plants. The percentage of P was higher in tissues of fertilized mycorrhial plants than in those mycorrihzed plants without or nonmycorrhized plants with added low-soluble P. These results indicated that plants in VAM symbiosis mobilize P better from low-soluble P than non-mycorrhized plants.En condiciones de casa de malla se evaluó el efecto de la infestación con micorrizas vesículo arbusculares (VAM en la asimilación de P por plantas de maíz (Zea mays, cv.DDH hybrid cultivadas en un Oxisol. Como micorriza se utilizó el hongo Glomus mosseae. En ambos tratamientos (con micorriza y sin ella se aplicó fosfato ferroso (FePO4.4H2O. La producción de MS de maíz fue mayor cuando se aplicaron el hongo + la fuente de P. La cantidad de P en el suelo con este tratamiento fue menor que en el suelo fertilizado pero sin aplicación del hongo. En las hojas de las plantas las mayores concentraciones de P se observaron igualmente en el tratamiento micorriza + aplicación de fertilizante.

  18. 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)

  19. Phosphate application to firing range soils for Pb immobilization: The unclear role of phosphate

    International Nuclear Information System (INIS)

    Chrysochoou, Maria; Dermatas, Dimitris; Grubb, Dennis G.

    2007-01-01

    Phosphate treatment has emerged as a widely accepted approach to immobilize Pb in contaminated soils and waste media, relying on the formation of the highly insoluble mineral pyromorphite as solubility-controlling phase for Pb. As such, phosphate treatment has been proposed as a Best Management Practice (BMP) for firing ranges where Pb occurs in its metallic forms and several other phases (carbonates, oxides). While pyromorphite thermodynamically has the potential to control Pb solubility at low levels, its formation is kinetically controlled by pH, the solubility of the phosphate source, and the solubility of Pb species. Treatability studies have shown that excess quantities of soluble and acidic phosphate sources, such as phosphoric acid, are necessary for successful in situ treatment. Even under these conditions, Extended X-ray Absorption Fine Structure (EXAFS), the only reliable method to identify and quantify Pb speciation, showed that Pb conversion to pyromorphite in in situ treated soils was less than 45% after 32 months. Furthermore, the use of lime (CaO) to restore soil pH in acidified soil treatments inhibited further conversion. Additionally, phosphate treatment is known to reduce bioavailability through pyromorphite formation in the intestinal tract, and the phytoaccumulation of Pb; both desirable effects for Pb-impacted areas. Given the costs of phosphate treatment, the use of biogenic phosphate sources, such as bone meal, may be a more environmentally sustainable approach toward this end. In the many studies focusing on phosphate treatment, the attendant P leaching and eutrophication have been largely overlooked, along with other issues such as the enhanced leaching of oxyanionic contaminants, such as Se, As and W. The success and sustainability of applying phosphate as a BMP in firing range soils therefore remain questionable

  20. Phase boundary effects in metal matrix embedded glasses

    International Nuclear Information System (INIS)

    Schiewer, E.

    1979-01-01

    An investigation was performed to study reactions at the phase boundaries of glass-lead composites at temperatures up to the softening point of the glass. Some metal was oxidized at the boundary and penetrated into the glass. Solid-state diffusion was rate controlling. In the case of a phosphate glass, fission products were depleted in the boundary area. Molybdenum migrated into the lead, and cesium migrated into the glass core. 2 figures, 3 tables

  1. 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

  2. Preparation and properties of β-tricalcium phosphate porous bioceramic

    Institute of Scientific and Technical Information of China (English)

    张士华; 熊党生; 崔崇

    2004-01-01

    Porous β-tricalcium phosphate bioceramic (PTCP) has important roles in surgical implants because of good biocompatibility. But the low compressive strength of the ceramic limits its application. The preparation of PTCP was improved with the adjustment of the constituents and the sintering-process. A new type of PTCP material with high compressive strength was made. The compositions, microstructure and properties of PTCP were analyzed by TG-DSC, XRD, TEM, SEM and so on. The result indicates that stearic acid burns sufficiently and gives out carbon dioxide and water vapor when slowly heated between 200 ℃ and 400 ℃ so that the porous structure like coral in β-TCP bioceramic is formed. Through crystallization at 470 ℃ and 570 ℃, more CaO-P2O5 glass-cement is converted into crystallite-glass, which is beneficial for improving the compressive strength of β-TCP bioceramic.PTCP can form a support action in bone imperfect section with good solubility.

  3. 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

  4. physico-chemical characterization of ogun and sokoto phosphate ...

    African Journals Online (AJOL)

    indicating their liming potential in the soil. ORP was more soluble in ... industry as a source of uranium and rare earth metals, ... limestones; and primary phosphatic shales, limestones ..... may help to reduce P leaching and run off losses after.

  5. A 25-year laboratory experiment on French SON68 nuclear glass leached in a granitic environment - First investigations

    Energy Technology Data Exchange (ETDEWEB)

    Guittonneau, C. [CEA Marcoule DTCD/SECM/LCLT, BP 17171, 30207 Bagnols-sur-Ceze Cedex (France); Gin, S., E-mail: stephane.gin@cea.f [CEA Marcoule DTCD/SECM/LCLT, BP 17171, 30207 Bagnols-sur-Ceze Cedex (France); Godon, N.; Mestre, J.P. [CEA Marcoule DTCD/SECM/LCLT, BP 17171, 30207 Bagnols-sur-Ceze Cedex (France); Dugne, O.; Allegri, P. [CEA Marcoule DTEC/SGCS/LMAC, BP 17171, 30207 Bagnols-sur-Ceze Cedex (France)

    2011-01-01

    We have investigated a 25.75-year old leaching experiment to improve our understanding of the mechanisms controlling glass dissolution in geological disposal conditions. A SON68 glass block was leached in slowly renewed synthetic groundwater (at 90 {sup o}C, 100 bar) in contact with some pieces of granite and Ni-Cr-Mo alloy as environmental storage materials. One hundred and sixty-three samplings were carried out over the entire duration of the experiment and were used to calculate the mean thickness of the altered glass (28 ({+-}9) {mu}m) and the glass dissolution rate. After few months, the rate remained very constant at 6 x 10{sup -3} g m{sup -2} d{sup -1} which is about 20 times higher than the residual rate measured in a batch reactor at the same temperature. At the end of the experiment, mainly SEM analyses were performed on the entire glass block. Surprisingly, the glass alteration layer has neither a homogeneous thickness, nor a homogeneous morphology. The location of the sampling valve (at half height of the glass block) seems to divide the glass block into two parts. In the upper half (above the sampling valve), the general morphology of the alteration layer consists in a relatively simple and uniform gel and some secondary phases which are rare-earth phosphates. The mean measured thickness of this alteration layer is 6.7 ({+-}0.3) {mu}m. However, in the lower half of the glass block, the gel is globally larger and frequently contains rounded shapes which are rare-earth phosphates. This section is edged by secondary phases bearing Mg, Na, Zn and Ni. The mean measured thickness is 81.3 ({+-}1.1) {mu}m in the lower half. In this experiment, the flow rate which leads to the hydrodynamic transport of the soluble species must be a key factor for the local glass alteration process. We have also shown that this unexpected behavior is likely due to heterogeneities of the chemistry of the solution. This conclusion is supported by the behavior of Mg. This element

  6. Characterisation and Properties of Lithium Disilicate Glass Ceramics in the SiO2-Li2O-K2O-Al2O3 System for Dental Applications

    Directory of Open Access Journals (Sweden)

    Naruporn Monmaturapoj

    2013-01-01

    Full Text Available This work proposes four different glass formulas derived from the SiO2-Li2O-K2O-Al2O3 system to investigate the effect of glass composition on their crystal formations and properties. Glass LD1 was SiO2-Li2O-K2O-Al2O3 system with the addition of P2O5 and CaF2 as nucleating agents. In Glass LD2, a slight amount of MgO was mixed in order to increase the viscosity of the melting glass. Finally, the important factor of Si : Li ratio was increased in Glasses LD3 and LD4 with compositions otherwise the same as LD1 and LD2. The results found that P2O5 and CaF2 served as a nucleating site for lithium phosphate and fluorapatite to encourage heterogenous nucleation and produce a fine-grained interlocking microstructure of lithium disilicate glass ceramics. MgO content in this system seemed to increase the viscosity of the melting glass and thermal expansion coefficient including the chemical solubility. Increasing the Si : Li ratio in glass compositions resulted in the change of the microstructure of Li2Si2O5 crystals.

  7. 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.

  8. Preparation and Characterization of Porous Calcium Phosphate Bioceramics

    Institute of Scientific and Technical Information of China (English)

    Honglian Dai; Xinyu Wang; Yinchao Han; Xin Jiang; Shipu Li

    2011-01-01

    β-tricalcium phosphate (β-TCP) powder and Na2O-CaO-MgO-P2O5 glass binder were synthesized and mixed, and then the biodegradable porous calcium phosphate ceramics were successfully prepared by foaming and sintering at 850℃. The as-prepared ceramics possess a high porosity with partial three-dimension interconnected macro- and micro-pores. As in vitro experiment testified, the calcium phosphate ceramics (CPCs) has good degradability.

  9. 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

  10. 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.

  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. 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

  13. Near net-shape fabrication of hydroxyapatite glass composites

    NARCIS (Netherlands)

    Zhu, Q.; With, de G.; Dortmans, L.; Feenstra, F.

    2004-01-01

    Near net-shape fabrication of hydroxyapatite (HA) glass composites has been attempted by infiltrating a glass into porous HA performs. Main efforts were put to develop glasses that are chemically compatible with HA at elevated temperatures. After extensive investigations in the phosphate and

  14. Optical properties of Eu3+ & Tb3+ ions doped alkali oxide (Li2O/ Na2O/ K2O) modified boro phosphate glasses for red, green lasers and display device applications

    Science.gov (United States)

    Moulika, G.; Sailaja, S.; Reddy, B. Naveen Kumar; Reddy, V. Sahadeva; Dhoble, S. J.; Reddy, B. Sudhakar

    2018-04-01

    In this article we report on alkali oxide modified borophosphate glasses doped with Eu3+and Tb3+ ions, with the chemical composition of 69.5 B2O3+10P2O5 + 10CaF2 + 5 Li2O+ 5ZnO+ R+ 0.5 Eu2O3 [where R = 5 (LiO2/Na2O/K2O)] have been prepared by conventional melt quenching technique, and the spectroscopic properties of the prepared glasses have been studied by XRD, Optical absorption, excitation and emission spectral analysis. XRD spectrum of the glasses have shown the amorphous nature of the glasses. The red emission corresponding to 5D0 → 7F2 (613 nm) transition was observed under the excitation of 394 nm wavelength, corresponding to Eu3+ ions, for all the prepared glasses. For Eu3+ ion doped glasses, emission bands were observed, such as; 5D1→ 7F1 (538 nm), 5D0→ 7F0 (580 nm), 5D0→ 7F1 (592 nm), 5D0→ 7F2 (613 nm), 5D0→ 7F3 (613 nm) and 5D0→ 7F4 (702 nm) are identified. In the case of Tb3+ ion doped glasses, four emission lines were observed, such as 5D4→ (7F6, 7F5, 7F4), which are located at 489 nm, 545 nm and 585 nm, respectively, after the samples were excited with 376 nm ultraviolet source. The green emission corresponding to 5D4 → 7F5 (543 nm) transition was observed under excitation wavelength 376 nm of the Tb3+ ions for all the prepared glasses. For all these emission bands, the decay curves were recorded to evaluate the emission life times. The mechanism underlying the observed emission from the glasses was explained in terms of energy levels.

  15. 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

  16. Survey of glass plutonium contents and poison selection

    Energy Technology Data Exchange (ETDEWEB)

    Plodinec, M.J.; Ramsey, W.G. [Westinghouse Savannah River Company, Aiken, SC (United States); Ellison, A.J.G.; Shaw, H. [Lawrence Livermore National Laboratory, CA (United States)

    1996-05-01

    If plutonium and other actinides are to be immobilized in glass, then achieving high concentrations in the glass is desirable. This will lead to reduced costs and more rapid immobilization. However, glasses with high actinide concentrations also bring with them undersirable characteristics, especially a greater concern about nuclear criticality, particularly in a geologic repository. The key to achieving a high concentration of actinide elements in a glass is to formulate the glass so that the solubility of actinides is high. At the same time, the glass must be formulated so that the glass also contains neutron poisons, which will prevent criticality during processing and in a geologic repository. In this paper, the solubility of actinides, particularly plutonium, in three types of glasses are discussed. Plutonium solubilities are in the 2-4 wt% range for borosilicate high-level waste (HLW) glasses of the type which will be produced in the US. This type of glass is generally melted at relatively low temperatures, ca. 1150{degrees}C. For this melting temperature, the glass can be reformulated to achieve plutonium solubilities of at least 7 wt%. This low melting temperature is desirable if one must retain volatile cesium-137 in the glass. If one is not concerned about cesium volatility, then glasses can be formulated which can contain much larger amounts of plutonium and other actinides. Plutonium concentrations of at least 15 wt% have been achieved. Thus, there is confidence that high ({ge}5 wt%) concentrations of actinides can be achieved under a variety of conditions.

  17. Partitioning and structural role of Mn and Fe ions in ionic sulfophosphate glasses

    Energy Technology Data Exchange (ETDEWEB)

    Möncke, Doris; Wondraczek, Lothar, E-mail: lothar.wondraczek@uni-jena.de [Otto-Schott-Institute of Materials Research, Friedrich-Schiller-University Jena, Fraunhoferstr. 6, 07743 Jena (Germany); Sirotkin, Sergey [Institut des Sciences Moléculaires - CNRS UMR 5255, Université de Bordeaux, 33405 Talence (France); Stavrou, Elissaios; Kamitsos, Efstratios I. [Theoretical and Physical Chemistry Institute, National Hellenic Research Foundation, 48 Vassileos Constaniou Ave., 116 35 Athens (Greece)

    2014-12-14

    Ionic sulfophosphate liquids of the type ZnO-Na{sub 2}O-Na{sub 2}SO{sub 4}-P{sub 2}O{sub 5} exhibit surprising glass forming ability, even at slow or moderate cooling rate. As a concept, they also provide high solubility of transition metal ions which could act as cross-linking sites between the sulfate and phosphate entities. It is therefore investigated how the replacement of ZnO by MnO and/or FeO affects the glass structure and the glass properties. Increasing manganese levels are found to result in a monotonic increase of the transition temperature T{sub g} and most of the mechanical properties. This trend is attributed to the change of metal-ion coordination from four-fold around Zn{sup 2+} to six-fold around Mn{sup 2+} ions. The higher coordination facilitates cross-linking of the ionic structural entities and subsequently increases T{sub g}. Raman and infrared spectroscopy show that the structure of these glasses involves only SO{sub 4}{sup 2−} and PO{sub 4}{sup 3−} monomers as well as P{sub 2}O{sub 7}{sup 4-} dimers. Replacement of ZnO by MnO is found to favour PO{sub 4}{sup 3−} over P{sub 2}O{sub 7}{sup 4-} species, a trend which is enhanced by co-doping with FeO. Both transition metal ions show, like Zn{sup 2+}, a preference to selectively coordinate to phosphate anionic species, as opposed to sodium ions which coordinate mainly to sulfate anions. EPR spectroscopy finally shows that divalent Mn{sup 2+} ions are present primarily in MnO{sub 6}-clusters, which, in the studied sulfophosphate glasses, convert upon increasing MnO content from corner-sharing to edge-sharing entities.

  18. Partitioning and structural role of Mn and Fe ions in ionic sulfophosphate glasses

    International Nuclear Information System (INIS)

    Möncke, Doris; Wondraczek, Lothar; Sirotkin, Sergey; Stavrou, Elissaios; Kamitsos, Efstratios I.

    2014-01-01

    Ionic sulfophosphate liquids of the type ZnO-Na 2 O-Na 2 SO 4 -P 2 O 5 exhibit surprising glass forming ability, even at slow or moderate cooling rate. As a concept, they also provide high solubility of transition metal ions which could act as cross-linking sites between the sulfate and phosphate entities. It is therefore investigated how the replacement of ZnO by MnO and/or FeO affects the glass structure and the glass properties. Increasing manganese levels are found to result in a monotonic increase of the transition temperature T g and most of the mechanical properties. This trend is attributed to the change of metal-ion coordination from four-fold around Zn 2+ to six-fold around Mn 2+ ions. The higher coordination facilitates cross-linking of the ionic structural entities and subsequently increases T g . Raman and infrared spectroscopy show that the structure of these glasses involves only SO 4 2− and PO 4 3− monomers as well as P 2 O 7 4- dimers. Replacement of ZnO by MnO is found to favour PO 4 3− over P 2 O 7 4- species, a trend which is enhanced by co-doping with FeO. Both transition metal ions show, like Zn 2+ , a preference to selectively coordinate to phosphate anionic species, as opposed to sodium ions which coordinate mainly to sulfate anions. EPR spectroscopy finally shows that divalent Mn 2+ ions are present primarily in MnO 6 -clusters, which, in the studied sulfophosphate glasses, convert upon increasing MnO content from corner-sharing to edge-sharing entities

  19. 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

  20. 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

  1. Investigation of possible delocalization of long-lived radionuclides from phosphate materials used for radioactive waste fixation into water of granite formations

    International Nuclear Information System (INIS)

    Krylova, N.V.; Salamatina, R.N.; Shavruk, V.V.; Yuzvikova, M.A.

    1990-01-01

    Study results of chemical stability of phosphate glass materials containing high-level waste imitators by their contact with imitators of strata waters of gratine formations within the interval 20-150 deg C, are presented. It is shown that above 100 deg C strontium, cesium and sodium discharge from vitrified high-level wastes is complicated because of deposition of difficulty soluble compounds of contact waters and leaching (solution) products of glass matrix on the surface of vitrified wastes. Layer thickness and element discharge into the water are determined by qualitative and quantative composition of the strata water, temperature interaction of materials with water and chemical stability of materials at the given temperature

  2. 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 ...

  3. Proton glass behaviour in a solid solution of gamma-irradiated deuterated betaine phosphate sub 0 sub . sub 1 sub 5 betaine phosphite sub 0 sub . sub 8 sub 5

    CERN Document Server

    Banys, J; Klimm, C; Voelkel, G; Kloepperpieper, A

    1997-01-01

    Measurements of the dielectric permittivity are reported for a deuterated solid solution of gamma-irradiated antiferroelectric (betainephosphate) sub 0 sub . sub 1 sub 5 ferroelectric (betainephosphite) sub 0 sub . sub 8 sub 5 at frequencies 20 H sub Z glass state. The activation energy was found to be E sub b = 311.6 K (0.027 eV). The Kutnjak model showed a non-typical glass behaviour with an estimated glass temperature of 55.4 K. (author). Letter-to-the-editor

  4. TUCS/phosphate mineralization of actinides

    Energy Technology Data Exchange (ETDEWEB)

    Nash, K.L. [Argonne National Lab., IL (United States)

    1997-10-01

    This program has as its objective the development of a new technology that combines cation exchange and mineralization to reduce the concentration of heavy metals (in particular actinides) in groundwaters. The treatment regimen must be compatible with the groundwater and soil, potentially using groundwater/soil components to aid in the immobilization process. The delivery system (probably a water-soluble chelating agent) should first concentrate the radionuclides then release the precipitating anion, which forms thermodynamically stable mineral phases, either with the target metal ions alone or in combination with matrix cations. This approach should generate thermodynamically stable mineral phases resistant to weathering. The chelating agent should decompose spontaneously with time, release the mineralizing agent, and leave a residue that does not interfere with mineral formation. For the actinides, the ideal compound probably will release phosphate, as actinide phosphate mineral phases are among the least soluble species for these metals. The most promising means of delivering the precipitant would be to use a water-soluble, hydrolytically unstable complexant that functions in the initial stages as a cation exchanger to concentrate the metal ions. As it decomposes, the chelating agent releases phosphate to foster formation of crystalline mineral phases. Because it involves only the application of inexpensive reagents, the method of phosphate mineralization promises to be an economical alternative for in situ immobilization of radionuclides (actinides in particular). The method relies on the inherent (thermodynamic) stability of actinide mineral phases.

  5. Corrosion resistance and in-vitro bioactivity of BaO containing Na2O-CaO-P2O5 phosphate glass-ceramic coating prepared on 316 L, duplex stainless steel 2205 and Ti6Al4V

    Science.gov (United States)

    Edathazhe, Akhila B.; Shashikala, H. D.

    2018-03-01

    The phosphate glass with composition 11Na2O-15BaO-29CaO-45P2O5 was coated on biomedical implant materials such as stainless steel 316 L, duplex stainless steel (DSS) 2205 and Ti6Al4V alloy by thermal enamelling method. The structural properties and composition of glass coated substrates were studied by x-ray diffraction (XRD), Scanning electron microscopy (SEM) and Energy dispersive x-ray spectroscopy (EDS) analysis. The coatings were partially crystalline in nature with porous structure and pore size varied from micro to nanometer range. The polarization curve was obtained for uncoated and coated substrates from electrochemical corrosion test which was conducted at 37 °C in Hank’s balanced salt solution (HBSS). The corrosion resistance of 316 L substrate increased after coating, whereas it decreased in case of DSS 2205 and Ti6Al4V. The XRD and SEM/EDS studies indicated the bioactive hydroxyapatite (HAp) layer formation on all the coated surfaces after electrochemical corrosion test, which improved the corrosion resistance. The observed electrochemical corrosion behavior can be explained based on protective HAp layer formation, composition and diffusion of ions on glass coated surfaces. The in-vitro bioactivity test was carried out at 37 °C in HBS solution for 14 days under static conditions for uncoated and coated substrates. pH and ion release rate measurements from the coated samples were conducted to substantiate the electrochemical corrosion test. The lower ion release rates of Na+ and Ca2+ from coated 316 L supported its higher electrochemical corrosion resistance among coated samples. Among the uncoated substrates, DSS showed higher electrochemical corrosion resistance. Amorphous calcium-phosphate (ACP) layer formation on all the coated substrates after in-vitro bioactivity test was confirmed by XRD, SEM/EDS and ion release measurements. The present work is a comparative study of corrosion resistance and bioactivity of glass coated and uncoated

  6. Effect of alumina on the dissolution rate of glasses

    International Nuclear Information System (INIS)

    Palavit, G.; Montagne, L.

    1997-01-01

    Small alumina addition to silicate glasses improves their chemical durability, but a large amount of alumina can also be beneficial to obtain a high dissolution rate. This paper describes the effect of Al 3+ on the early stage of glass alteration, in relation with its coordination in the glass and also with the reactions involved (hydrolysis and ionic exchange). We describe briefly nuclear magnetic resonance tools available to characterize the aluminum environments in the glasses. The rote of alumina on the dissolution rate of phosphate glasses is also discussed in order to show that the effect of Al 3+ is dependant upon the nature of the glass matrix. (author)

  7. X-ray absorption spectroscopy on phosphoric-salt pellets. Determination of the geometric and electronic structure of metal-oxide doped sodium-phosphate glasses; Roentgenabsorptionsspektroskopie an Phosphorsalzperlen. Bestimmung der geometrischen und elektronischen Struktur von metalloxid-dotierten Natriumphosphatglaesern

    Energy Technology Data Exchange (ETDEWEB)

    Brendebach, B.

    2004-02-01

    Sodium metaphosphate glasses doped with transition metal oxides show characteristic colors. X-ray absorption spectroscopy (XAS) investigations provide information whether the coloration stems from different electronic transitions or changes in the geometrical structure of the glasses. Even though the violet color of MnO{sub y}-doped glasses is considered as an evidence for Mn{sup 3+}-ions, Mn K-XAS reveals that the majority of the manganese ions are in the oxidation state +II and have a mixed coordination of four and six oxygen atoms, respectively. The oxygen coordination around the nickel ions in NiO-doped glasses with different metall oxide concentrations is always six. The change of color from citreous to auburn with increasing nickel oxide content is attributed to a systematic change in the bonding characteristic from mainly ionic-like to a small but significant contribution of covalent-like bonding. Analysis of higher coordination shells provides no indication of the formation of metal oxide clusters. (orig.)

  8. Field evaluation of water or citrate soluble phosphorus in modified phosphate rocks for soybean Avaliação agronômica do fósforo solúvel em água ou citrato de fosfatos de rocha acidulados para a soja

    Directory of Open Access Journals (Sweden)

    Luís Ignácio Prochnow

    2001-03-01

    Full Text Available Ten P fertilizers were collected (commercial fertilizers or synthesized (experimental sources in order to obtain single superphosphates varying in water and citrate solubility. A standard source of P was also produced by crystallization of the water-soluble fraction of a triple superphosphate. Eleven P sources were band applied to a medium textured Xanthic Hapludox, in Bahia, Brazil (low content of resin-extractable P at a rate of 80 kg ha-1 of NAC + H2O (neutral ammonium citrate plus water soluble P2O5, with soybean as the crop which was grown to maturity. A check plot (control was included in the study. Three of the P sources [single superphosphate produced from Araxa phosphate rock (PR, low-grade single superphosphate produced from Lagamar PR and the standard source of P] were also applied at rates to provide 40 and 120 kg ha-1 of NAC + H2O soluble P2O5. Yield of soybean was evaluated by analysis of variance with mean comparison performed utilizing LSD lines, considering the P sources applied at a rate of 80 kg ha-1 of P2O5 + control. Regression procedures were used to study the relation between yield of soybean and rates of P2O5. The fertilizers tested performed equally well as a source of P for soybean. The level of water-soluble P did not influence fertilizer performance.Dez fontes de P foram coletadas em unidades revendedoras de fertilizantes comerciais ou produzidas em laboratório de tal forma a obter superfosfatos simples com variabilidade em água e citrato neutro de amônio + água (CNA + H2O. Utilizou-se como fonte padrão de fósforo a fração solubilizada, filtrada e cristalizada de um superfosfato triplo. As onze fontes de P foram aplicadas nas linhas de semeadura de soja de um Xanthic Hapludox textura média, localizado no Município de Barreiras, Bahia (baixo teor de fósforo resina na dose de 80 kg ha-1 de P2O5 solúvel em CNA + H2O. Três das fontes (superfosfatos simples produzido a partir da rocha fosfática de Araxá e

  9. The chemistry of copper chalcogenides in waste glasses

    International Nuclear Information System (INIS)

    Schreiber, H.D.; Lambert, H.W.

    1994-01-01

    The solubilities of copper chalcogenides (CuS, CuSe, CuTe) were measured in a glass melt which is representative of those proposed for nuclear waste immobilization and circuit board vitrification. CuTe is more soluble than CuS and CuSe in the glass melt under relatively oxidizing conditions. However, the solubilities of all the copper chalcogenides in the glass melt are virtually identical at reducing conditions, probably a result of the redox-controlled solubility of copper metal in all cases. The redox chemistry of a glass melt coexisting with an immiscible copper chalcogenide depends primarily on the prevailing oxygen fugacity, not on the identity of the chalcogenide. The target concentration of less than 0.3 to 0.5 wt% copper in the waste glass should eliminate the precipitation of copper chalcogenides during processing

  10. 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....

  11. Spent fuel from nuclear research reactors immobilized in sintered glass

    International Nuclear Information System (INIS)

    Mateos, P.; Russo, D.O.; Rodriguez, D.; Heredia, A.; Sanfilippo, M.; Sterba, M.

    2002-01-01

    Different kinds of glasses, borosilicates, Iron borosilicates and Iron phosphates, were tested in order to determine its capability to immobilize calcined uranium silicide in a sintering process. Iron phosphate glass developed in our laboratory showed the best results in SEM analysis. Also its gravimetric leaching rate is less than 0.45 g.m -2 .day -1 for 7 and 10% loading which is lower than any previously studied for us. (author)

  12. Phosphate removal from digested sludge supernatant using modified fly ash.

    Science.gov (United States)

    Xu, Ke; Deng, Tong; Liu, Juntan; Peng, Weigong

    2012-05-01

    The removal of phosphate in digested sludge supernatant by modified coal fly ash was investigated in this study. Modification of the fly ash by the addition of sulfuric acid could significantly enhance its immobilization ability. The experimental results also showed that adsorption of phosphate by the modified fly ash was rapid with the removal percentage of phosphate reaching an equilibrium of 98.62% in less than 5 minutes. The optimum pH for phosphate removal was 9 and the removal percentage increased with increasing adsorbent dosage. The effect of temperature on phosphate removal efficiency was not significant from 20 to 40 degrees C. X-ray diffraction and scanning electron microscope analyses showed that phosphate formed an amorphous precipitate with water-soluble calcium, aluminum, and iron ions in the modified fly ash.

  13. 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.

  14. DEPENDENCY OF SULFATE SOLUBILITY ON MELT COMPOSITION AND MELT POLYMERIZATION

    International Nuclear Information System (INIS)

    JANTZEN, CAROL M.

    2004-01-01

    Sulfate and sulfate salts are not very soluble in borosilicate waste glass. When sulfate is present in excess it can form water soluble secondary phases and/or a molten salt layer (gall) on the melt pool surface which is purported to cause steam explosions in slurry fed melters. Therefore, sulfate can impact glass durability while formation of a molten salt layer on the melt pool can impact processing. Sulfate solubility has been shown to be compositionally dependent in various studies, (e.g. , B2O3, Li2O, CaO, MgO, Na2O, and Fe2O3 were shown to increase sulfate solubility while Al2O3 and SiO2 decreased sulfate solubility). This compositional dependency is shown to be related to the calculated melt viscosity at various temperatures and hence the melt polymerization

  15. Solubility of sparingly soluble drug derivatives of anthranilic acid.

    Science.gov (United States)

    Domańska, Urszula; Pobudkowska, Aneta; Pelczarska, Aleksandra

    2011-03-24

    This work is a continuation of our systematic study of the solubility of pharmaceuticals (Pharms). All substances here are derivatives of anthranilic acid, and have an anti-inflammatory direction of action (niflumic acid, flufenamic acid, and diclofenac sodium). The basic thermal properties of pure Pharms, i.e., melting and glass-transition temperatures as well as the enthalpy of melting, have been measured with the differential scanning microcalorimetry technique (DSC). Molar volumes have been calculated with the Barton group contribution method. The equilibrium mole fraction solubilities of three pharmaceuticals were measured in a range of temperatures from 285 to 355 K in three important solvents for Pharm investigations: water, ethanol, and 1-octanol using a dynamic method and spectroscopic UV-vis method. The experimental solubility data have been correlated by means of the commonly known G(E) equation: the NRTL, with the assumption that the systems studied here have revealed simple eutectic mixtures. pK(a) precise measurement values have been investigated with the Bates-Schwarzenbach spectrophotometric method. © 2011 American Chemical Society

  16. Uranium from phosphate ores

    International Nuclear Information System (INIS)

    Hurst, F.J.

    1983-01-01

    The following topics are described briefly: the way phosphate fertilizers are made; how uranium is recovered in the phosphate industry; and how to detect covert uranium recovery operations in a phsophate plant

  17. 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....

  18. 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....

  19. 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.

  20. Gas solubilities widespread applications

    CERN Document Server

    Gerrard, William

    1980-01-01

    Gas Solubilities: Widespread Applications discusses several topics concerning the various applications of gas solubilities. The first chapter of the book reviews Henr's law, while the second chapter covers the effect of temperature on gas solubility. The third chapter discusses the various gases used by Horiuti, and the following chapters evaluate the data on sulfur dioxide, chlorine data, and solubility data for hydrogen sulfide. Chapter 7 concerns itself with solubility of radon, thoron, and actinon. Chapter 8 tackles the solubilities of diborane and the gaseous hydrides of groups IV, V, and

  1. 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.)

  2. Standard characterization of phosphate rock samples from the FAO/IAEA phosphate project

    International Nuclear Information System (INIS)

    Binh, Truong; Zapata, F.

    2002-01-01

    Phosphate rocks (PR) are phosphate-bearing minerals that vary widely in their inherent characteristics and consequently their agronomic potential. In the framework of a FAO/IAEA networked research project, the evaluation of the agronomic effectiveness of natural and modified PR products under a variety of soil climate and crop management conditions was carried out. The characterization of phosphate rocks is the first and essential step in evaluating their suitability for direct application. If several PR sources are utilized, standardized methods should be used for comparison purposes to determine their agronomic potential. This paper describes the standard characterization of phosphate rock products utilized in the project, in particular the mineralogical and crystallographic analyses, physical analyses, chemical composition and solubility in conventional reagents. A total of 28 phosphate rock samples from 15 countries were collected and analyzed in specialized laboratories. The data on mineralogy, chemical composition and solubility in conventional reagents are closely interrelated. An arbitrary classification of the reactivity of the PR samples was made based on the solubility indices in conventional reagents. On another hand, the results of the crystallographic parameters, calculated indices of absolute solubility, specific surface and porosity reflect the variability of the physical state and the sample pre-conditioning treatment of the analyzed products. A proper characterization of phosphate rock samples should provide the maximum of basic information that can be obtained in a cost-effective manner in normal chemical laboratories. Based on the results of this characterization, the following determinations are recommended: a description of the sample, major elemental (total P, Ca, Mg) composition, solubility in conventional reagents (neutral ammonium citrate, citric and formic acid) and particle size analysis. The classification of PR samples for direct

  3. Long term effects of bioactive glass particulates on dental pulp stem cells in vitro

    Directory of Open Access Journals (Sweden)

    Gholami Sanaz

    2017-12-01

    Full Text Available Bioactive glasses (BG are known for their ability to induce bone formation by the action of their dissolution products. Glasses can deliver active ions at a sustained rate, determined by their composition and surface area. Nanoporous sol-gel derived BGs can biodegrade rapidly, which can lead to a detrimental burst release of ions and a pHrise. The addition of phosphate into the glass can buffer the pH during dissolution. Here, dissolution of BG with composition 60 mol% SiO2, 28 mol% CaO and 12 mol% P2O5 at 600 μg/ml were investigated. Initially, the dissolution and apatite formation of the BG particulates were examined in simulated body fluid using FTIR and XRD. BG particulates were indirectly exposed to dental pulp stem cells, and the effect of 14 days continuous ion release on human dental pulp stem cells (hDPSC viability and differentiation was evaluated. Alamar blue assay showed that cell proliferation was not inhibited by the continuous release of Ca, P and soluble silica. In fact, hDPSC in the presence of BG particulate displayed a higher density of mineralized nodules than untreated cells, as assessed by Alizarin red. The results will have a great contribution to the in vivo application of this particular BG.

  4. Uranium and thorium phosphate based matrices; syntheses, characterizations and lixiviation

    International Nuclear Information System (INIS)

    Dacheux, N.

    1995-03-01

    In the framework of the search for a ceramic material usable in the radioactive waste storage, uranium and thorium phosphates have been investigated. Their experimental synthesis conditions have been entirely reviewed, they lead to the preparation of four new compounds: U(UO 2 )(PO 4 ) 2 , U 2 O(PO 4 ) 2 , UC1PO 4 ,H 2 O, and Th 4 (PO 4 ) 4 , U 2 O 3 P 2 O 7 and Th 3 (PO 4 ) 4 . Characterization by several techniques (X-rays and neutron powder diffractions, UV-Visible and Infra-red spectroscopies, XPS,...) were performed. The ab initio structure determination of U(UO 2 )(PO 4 ) 2 has been achieved by X-rays and refined by neutron diffractions. Through its physico-chemical analysis, we found that this compound was a new mixed valence uranium phosphate in which U 4+ and UO 2 2+ ions are ordered in pairs along parallel chains according to a new type of arrangement. Reaction mechanism, starting from UC1PO 4 , 4H 2 O and based on redox processes of uranium in solid state was set up. From two main matrices U(UO 2 )(PO 4 ) 2 and Th 4 (PO 4 ) 4 P 2 O 7 , solid solutions were studied. They consist of replacement of U(IV) by Th(IV) and reversely. The leaching tests on pure, loaded and doped matrices were performed in terms of storage time, pH of solutions, and determined by the use of solids labelled with 230 U or by the measurement of uranyl concentration by Laser-Induced Time-Resolved Spectrofluorometry. Average concentration of uranium in the liquid phase is around 10 -4 M to 10 -6 M. Taking into account the very low solubilities of the studied phosphate ceramics, we estimated their chemical performances promising as an answer to the important nuclear waste problem, if we compare them to the glasses used at the present time. (author). 47 figs., 23 tabs., 6 appendixes