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Sample records for cation selective glass

  1. Cation coordination in oxychloride glasses

    Science.gov (United States)

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

    2003-02-01

    Glasses containing mixtures of cations and anions of nominal compositions [Sb2O3]x - [ZnCl2]1-x where x = 0.25, 0.50, 0.75, and 1.00, have been studied by means of neutron diffraction and Raman and Mössbauer spectroscopy. There is preferential bonding within the system with the absence of Sb-Cl bonds. Antimony is found to be threefold coordinated to oxygen, and zinc fourfold coordinated. The main contributing species are of the form [Sb(OSb)2(OZn)] and [Zn(ClZn)2(OSb)2].

  2. Cation coordination in oxychloride glasses

    International Nuclear Information System (INIS)

    Glasses containing mixtures of cations and anions of nominal compositions [Sb2O3]x - [ZnCl2]1-x where x = 0.25, 0.50, 0.75, and 1.00, have been studied by means of neutron diffraction and Raman and Moessbauer spectroscopy. There is preferential bonding within the system with the absence of Sb-Cl bonds. Antimony is found to be threefold coordinated to oxygen, and zinc fourfold coordinated. The main contributing species are of the form [Sb(OSb)2(OZn)] and [Zn(ClZn)2(OSb)2

  3. Cation coordination in oxychloride glasses

    Energy Technology Data Exchange (ETDEWEB)

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

    2003-02-19

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

  4. Mixed cation effect in sodium aluminosilicate glasses

    DEFF Research Database (Denmark)

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

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

  5. Inward Cationic Diffusion and Percolation Transition in Glass-Ceramics

    DEFF Research Database (Denmark)

    Smedsklaer, Morten Mattrup; Yue, Yuanzheng; Mørup, Steen

    2010-01-01

    We show the quantitative correlation between the degree of crystallization and the cationic diffusion extent in iron-containing diopside glass–ceramics at the glass transition temperature. We find a critical degree of crystallization, above which the diffusion extent sharply drops with the degree...... disconnected glass phase....

  6. Chemical bonding and structural ordering of cations in silicate glasses

    International Nuclear Information System (INIS)

    The specific surrounding of cations in multicomponent silicate glasses is briefly presented. Information about interatomic distances and site geometry may be gained by using spectroscopic methods among which x-ray absorption spectroscopy may be used for the largest number of glass components. Scattering of x-rays and neutrons may also be used to determine the importance of medium range order around specific cations. All the existing data show that cations occur in sites with a well-defined geometry, which are in most cases connected to the silicate polymeric network. Medium range order has been detected around cations such as Ti, Ca and Ni, indicating that these elements have an heterogeneous distribution within the glassy matrix. (authors)

  7. Structural Role of Alkali Cations in Calcium Aluminosilicate Glasses as Examined Using Oxygen-17 Solid-State Nuclear Magnetic Resonance Spectroscopy

    Science.gov (United States)

    Sukenaga, Sohei; Kanehashi, Koji; Shibata, Hiroyuki; Saito, Noritaka; Nakashima, Kunihiko

    2016-08-01

    The structural roles of alkali and calcium cations are important for understanding the physical and chemical properties of aluminosilicate melts and glasses. Recently, oxygen-17 nuclear magnetic resonance (17O NMR) studies of calcium-sodium aluminosilicate glasses showed that these structural roles are not randomly given, but rather each cation has its own preferential role. However, the relationship between cation type and role preference in calcium aluminosilicate glass is not completely understood. In the present study, the structural roles of lithium, sodium, and potassium cations in selected calcium aluminosilicate glasses are investigated using 17O solid-state NMR experiments. Data from these experiments clearly show that potassium cations have a notably stronger tendency to act as charge compensators within the network structure, compared to sodium and lithium cations. The result of 17O NMR experiment also showed that sodium and lithium cations in part act as network modifier alongside with calcium cations.

  8. Structural Role of Alkali Cations in Calcium Aluminosilicate Glasses as Examined Using Oxygen-17 Solid-State Nuclear Magnetic Resonance Spectroscopy

    Science.gov (United States)

    Sukenaga, Sohei; Kanehashi, Koji; Shibata, Hiroyuki; Saito, Noritaka; Nakashima, Kunihiko

    2016-05-01

    The structural roles of alkali and calcium cations are important for understanding the physical and chemical properties of aluminosilicate melts and glasses. Recently, oxygen-17 nuclear magnetic resonance (17O NMR) studies of calcium-sodium aluminosilicate glasses showed that these structural roles are not randomly given, but rather each cation has its own preferential role. However, the relationship between cation type and role preference in calcium aluminosilicate glass is not completely understood. In the present study, the structural roles of lithium, sodium, and potassium cations in selected calcium aluminosilicate glasses are investigated using 17O solid-state NMR experiments. Data from these experiments clearly show that potassium cations have a notably stronger tendency to act as charge compensators within the network structure, compared to sodium and lithium cations. The result of 17O NMR experiment also showed that sodium and lithium cations in part act as network modifier alongside with calcium cations.

  9. NMR investigation of cation distribution in HLW wasteform glass

    International Nuclear Information System (INIS)

    Magic-angle-spinning NMR has been used to establish the structural roles of various cations added to the borosilicate glass which is used for the vitrification of high-level nuclear waste (HLW). Representative surrogate oxides with nominal valencies of +1, +2 and +3 have been studied which span the range of oxides from modifier to intermediate and conditional glass former. NMR has been carried out on those nuclei which are accessible and the species observed have been correlated with the physical and chemical behaviour. The controlling factor is the manner in which the alkali cations partition between the various network groups, changing the distribution of silicon Qn species and the boron N4 ratio. Identifiable super-structural units are also present in these glasses. The aqueous corrosion rate increases with Q3 content, as does the weight loss due to evaporation from the melt. The activation energy for DC conduction scales with N4. Values of N4 obtained for these glasses deviate significantly from those predicted by the currently accepted model (Dell and Bray) and are strongly affected by the modifier or intermediate nature of the surrogate oxide and also by its effect on the distribution of non bridging oxygens between the silicate and borate polyhedra. (authors)

  10. Glass-water interaction: Effect of high-valence cations on glass structure and chemical durability

    Science.gov (United States)

    Hopf, J.; Kerisit, S. N.; Angeli, F.; Charpentier, T.; Icenhower, J. P.; McGrail, B. P.; Windisch, C. F.; Burton, S. D.; Pierce, E. M.

    2016-05-01

    Borosilicate glass is a durable solid, but it dissolves when in contact with aqueous fluids. The dissolution mechanism, which involves a variety of sequential reactions that occur at the solid-fluid interface, has important implications for the corrosion resistance of industrial and nuclear waste glasses. In this study, spectroscopic measurements, dissolution experiments, and Monte Carlo simulations were performed to investigate the effect of high-valence cations (HVC) on the mechanisms of glass dissolution under dilute and near-saturated conditions. Raman and NMR spectroscopy were used to determine the structural changes that occur in glass, specifically network formers (e.g., Al, Si, and B), with the addition of the HVC element hafnium in the Na2O-Al2O3-B2O3-HfO2-SiO2 system (e.g., Na/[Al + B] = 1.0 and HfO2/SiO2 from 0.0 to 0.42). Spectroscopic measurements revealed that increasing hafnium content decreases N4 (tetrahedral boron/total boron) and increases the amount of Si-O-Hf moieties in the glass. Results from flow-through experiments conducted under dilute and near-saturated conditions show a decrease of approximately 100× or more in the dissolution rate over the series from 0 to 20 mol% HfO2. Comparing the average steady-state rates obtained under dilute conditions to the rates obtained for near-saturated conditions reveals a divergence in the magnitude between the average steady state rates measured in these different conditions. The reason for this divergence was investigated more thoroughly using Monte Carlo simulations. Simulations indicate that the divergence in glass dissolution behavior under dilute and near-saturated conditions result from the stronger binding of Si sites that deposit on the surface from the influent when Hf is present in the glass. As a result, the residence time at the glass surface of these newly-formed Si sites is longer in the presence of Hf, which increases the density of anchor sites from which altered layers with higher Si

  11. Adsorption of Cationic Peptides to Solid Surfaces of Glass and Plastic

    DEFF Research Database (Denmark)

    Kristensen, Kasper; Henriksen, Jonas Rosager; Andresen, Thomas Lars

    2015-01-01

    peptides adsorb to solid surfaces of glass and plastic. Specifically, we use analytical HPLC to systematically quantify the adsorption of the three cationic membraneactive peptides mastoparan X, melittin, and magainin 2 to the walls of commonly used glass and plastic sample containers. Our results show...

  12. Dynamics of mobile ions in single- and mixed-cation glasses

    International Nuclear Information System (INIS)

    To study the ion dynamics of several inorganic glasses, including single- and mixed-cation glasses, we have determined conductivity spectra over wide ranges in frequency. In the case of the single-cation glasses, these spectra extend from a few hertz up to the terahertz regime. The spectra show a transition from their dc values to a dispersive regime where the conductivity increases continuously with frequency, tending towards a linear frequency dependence at sufficiently low temperatures. At high frequencies the dynamic conductivity is governed by vibrational contributions, whereas ionic hopping sequences determine the low-frequency part of the spectra. In an intermediate-frequency regime, both hopping and vibrational contributions contribute to the dynamic conductivity. The shape of the high-frequency conductivity spectra is discussed for various glasses. The low-frequency spectra are discussed in the framework of the concept of mismatch and relaxation. For the mixed-cation glasses where spectra have been taken by impedance spectroscopy, we report on a new kind of mixed-alkali effect. In contrast to conductivity spectra of single-cation glasses which follow the time-temperature superposition principle, featuring a temperature-invariant shape, the shapes of the conductivity spectra of the mixed-alkali glasses studied here are found to change with temperature. To explain this effect, we suggest differently activated mobilities of the two different ionic species

  13. Infrared spectroscopy of mass-selected metal carbonyl cations

    Science.gov (United States)

    Ricks, A. M.; Reed, Z. E.; Duncan, M. A.

    2011-04-01

    Metal carbonyl cations of the form M(CO)n+ are produced in a molecular beam by laser vaporization in a pulsed nozzle source. These ions, and their corresponding rare gas atom "tagged" analogs, M(CO)n(RG)m+, are studied with mass-selected infrared photodissociation spectroscopy in the carbonyl stretching region and with density functional theory computations. The number of infrared-active bands, their frequency positions, and their relative intensities provide distinctive patterns allowing determination of the geometries and electronic structures of these complexes. Cobalt penta carbonyl and manganese hexacarbonyl cations are compared to isoelectronic iron pentacarbonyl and chromium hexacarbonyl neutrals. Gold and copper provide examples of "non-classical" carbonyls. Seven-coordinate carbonyls are explored for the vanadium group metal cations (V +, Nb + and Ta +), while uranium cations provide an example of an eight-coordinate carbonyl.

  14. Glass transition temperature of a cationic polymethacrylate dependent on the plasticizer content - Simulation vs. experiment

    Science.gov (United States)

    Wagner, Karl G.; Maus, Martin; Kornherr, Andreas; Zifferer, Gerhard

    2005-04-01

    Atomistic molecular dynamics simulations ( NPT ensemble) are performed to compute the specific volume as a function of temperature of cationic polymethacrylate (Eudragit ® RS) with varying plasticizer (triethylcitrate) content ranging from pure polymer to a plasticizer weight proportion of 7.70%. The simulated glass transition temperature of these polymer-plasticizer blends is determined as the temperature marking the kink in the slope of specific volume vs. temperature plots. A linear dependence of the glass transition temperature on the plasticizer content is found. The computational findings are supported by differential scanning calorimetry experiments showing the same trend thus validating the applied computational method.

  15. Impact of cationic diffusion on properties of iron-bearing glass fibres

    DEFF Research Database (Denmark)

    Smedskjaer, Morten M.; Yue, Yuanzheng; Deubener, Joachim; Mørup, Steen

    2010-01-01

    A silica-rich surface layer of Fe3+-containing aluminosilicate glass fibres is created by means of an inward diffusion process of divalent network modifying cations. The latter is caused by the reduction of Fe3+ to Fe2+ when the fibres undergo a heat treatment at temperatures around the glass...... transition temperature (Tg) in a reducing H2/N2 atmosphere. The thickness of the surface layer can be adjusted by varying the temperature or the duration of the heat treatment. The reduction process has a significant impact on the glass transition and crystallization behaviour, high temperature stability...... (HTS), and chemical durability of the fibres. The reduction deteriorates the HTS of the fibres in argon due to the decrease of Tg and increase of the crystallization temperatures. However, the crystallization behaviour and HTS in air are not affected by the reduction. This is because a re-oxidation of...

  16. Mechanism of selective ion flotation. 1. Selective flotation of transition metal cations

    International Nuclear Information System (INIS)

    An experimental investigation is presented of the batch ion flotation of the transition metal cations Cr3+, Fe3+, Mn2+, Co2+, Zn2+, Ag+, Cd2+, and In3+ from acidic aqueous solutions with sodium dodecylsulfonate and sodium dodecylbenzenesulfonate as anionic surfactants. The selectivity sequences Mn2+ 2+ 2+ 3+ 3+ and Ag+ 2+ 3+ are established, both from data for single and multi-ion metal cations solutions, where sublate was not formed in the bulk solution. Good agreement between the selectivity sequences and the values of ionic potential of metal cations was found. An experimental investigation was also performed on the solubility of sublates. The sublates solubility values are discussed in terms of ionic potentials of metal cations as well as of the surfactant size

  17. Adsorption of cationic peptides to solid surfaces of glass and plastic.

    Directory of Open Access Journals (Sweden)

    Kasper Kristensen

    Full Text Available Cationic membrane-active peptides have been studied for years in the hope of developing them into novel types of therapeutics. In this article, we investigate an effect that might have significant experimental implications for investigators who wish to study these peptides, namely, that the peptides adsorb to solid surfaces of glass and plastic. Specifically, we use analytical HPLC to systematically quantify the adsorption of the three cationic membrane-active peptides mastoparan X, melittin, and magainin 2 to the walls of commonly used glass and plastic sample containers. Our results show that, at typical experimental peptide concentrations, 90% or more of the peptides might be lost from solution due to rapid adsorption to the walls of the sample containers. Thus, our results emphasize that investigators should always keep these adsorption effects in mind when designing and interpreting experiments on cationic membrane-active peptides. We conclude the article by discussing different strategies for reducing the experimental impact of these adsorption effects.

  18. Processing metallic glasses by selective laser melting

    Directory of Open Access Journals (Sweden)

    Simon Pauly

    2013-01-01

    Full Text Available Metallic glasses and their descendants, the so-called bulk metallic glasses (BMGs, can be regarded as frozen liquids with a high resistance to crystallization. The lack of a conventional structure turns them into a material exhibiting near-theoretical strength, low Young's modulus and large elasticity. These unique mechanical properties can be only obtained when the metallic melts are rapidly cooled to bypass the nucleation and growth of crystals. Most of the commonly known and used processing routes, such as casting, melt spinning or gas atomization, have intrinsic limitations regarding the complexity and dimensions of the geometries. Here, it is shown that selective laser melting (SLM, which is usually used to process conventional metallic alloys and polymers, can be applied to implement complex geometries and components from an Fe-base metallic glass. This approach is in principle viable for a large variety of metallic alloys and paves the way for the novel synthesis of materials and the development of parts with advanced functional and structural properties without limitations in size and intricacy.

  19. Effect of electrolytes on wettability of glass surface using anionic and cationic surfactant solutions.

    Science.gov (United States)

    Chaudhuri, Rajib Ghosh; Paria, Santanu

    2014-01-01

    Wetting behavior of a flat glass surface using pure nonionic, anionic, and cationic surfactants solutions has been studied by the dynamic contact angle (Wilhelmy plate) measurement technique. The advancing contact angle increases with the increasing concentration of surfactant and the value is maximum in the presence of cationic surfactant CTAB. The effect of different electrolytes in the presence of ionic surfactants was also studied to see the wetting behavior in the presence of electrolytes. The presence of electrolytes on ionic surfactant solutions significantly enhance the contact angle at very low concentration, which in turn lead to reduction in ionic surfactant requirement by more than 90% to achieve a particular contact angle. The effectiveness of electrolyte highly depends on the valance of counter ion. The reduction of ionic surfactant requirement is mostly useful for different applications such as flotation, and colloidal stability to reduce the production cost as well as environmental pollution. PMID:24183426

  20. Modulation of mechanosensitive calcium-selective cation channels by temperature

    Science.gov (United States)

    Ding, J. P.; Pickard, B. G.

    1993-01-01

    Gating of associations of mechanosensitive Ca(2+)-selective cation co-channels in the plasmalemma of onion epidermis has a strong and unusual temperature dependence. Tension-dependent activity rises steeply as temperature is lowered from 25 degrees C to about 6 degrees C, but drops to a low level at about 5 degrees C. Under the conditions tested (with Mg2+ and K+ at the cytosolic face of outside-out membrane patches), promotion results both from more bursting at all observed linkage levels and from longer duration of bursts of co-channels linked as quadruplets and quintuplets. Co-channel conductance decreases linearly, but only modestly, with declining temperature. It is proposed that these and related mechanosensitive channels may participate in a variety of responses to temperature, including thermonasty, thermotropism, hydrotropism, and both cold damage and cold acclimation.

  1. Modifier cation effects on 29Si nuclear shielding anisotropies in silicate glasses

    Science.gov (United States)

    Baltisberger, Jay H.; Florian, Pierre; Keeler, Eric G.; Phyo, Pyae A.; Sanders, Kevin J.; Grandinetti, Philip J.

    2016-07-01

    We have examined variations in the 29Si nuclear shielding tensor parameters of SiO4 tetrahedra in a series of seven alkali and alkaline earth silicate glass compositions, Cs2O · 4.81 SiO2, Rb2O · 3.96 SiO2, Rb2O · 2.25 SiO2, K2O · 4.48 SiO2, Na2O · 4.74 SiO2, BaO · 2.64 SiO2, and SrO · 2.36 SiO2, using natural abundance 29Si two-dimensional magic-angle flipping (MAF) experiments. Our analyses of these 2D spectra reveal a linear dependence of the 29Si nuclear shielding anisotropy of Q(3) sites on the Si-non-bridging oxygen bond length, which in turn depends on the cation potential and coordination of modifier cations to the non-bridging oxygen. We also demonstrate how a combination of Cu2+ as a paramagnetic dopant combined with echo train acquisition can reduce the total experiment time of 29Si 2D NMR measurements by two orders of magnitude, enabling higher throughput 2D NMR studies of glass structure.

  2. Modifier cation effects on (29)Si nuclear shielding anisotropies in silicate glasses.

    Science.gov (United States)

    Baltisberger, Jay H; Florian, Pierre; Keeler, Eric G; Phyo, Pyae A; Sanders, Kevin J; Grandinetti, Philip J

    2016-07-01

    We have examined variations in the (29)Si nuclear shielding tensor parameters of SiO4 tetrahedra in a series of seven alkali and alkaline earth silicate glass compositions, Cs2O·4.81 SiO2, Rb2O·3.96 SiO2, Rb2O·2.25 SiO2, K2O·4.48 SiO2, Na2O·4.74 SiO2, BaO·2.64 SiO2, and SrO·2.36 SiO2, using natural abundance (29)Si two-dimensional magic-angle flipping (MAF) experiments. Our analyses of these 2D spectra reveal a linear dependence of the (29)Si nuclear shielding anisotropy of Q((3)) sites on the Si-non-bridging oxygen bond length, which in turn depends on the cation potential and coordination of modifier cations to the non-bridging oxygen. We also demonstrate how a combination of Cu(2+) as a paramagnetic dopant combined with echo train acquisition can reduce the total experiment time of (29)Si 2D NMR measurements by two orders of magnitude, enabling higher throughput 2D NMR studies of glass structure. PMID:27187210

  3. Glass–water interaction: Effect of high-valence cations on glass structure and chemical durability

    Energy Technology Data Exchange (ETDEWEB)

    Hopf, J.; Kerisit, Sebastien N.; Angeli, F.; Charpentier, Thibault M.; Icenhower, Jonathan P.; McGrail, Bernard P.; Windisch, Charles F.; Burton, Sarah D.; Pierce, Eric M.

    2016-05-15

    Borosilicate glass is a durable solid, but it dissolves when in contact with aqueous fluids. The dissolution mechanism, which involves a variety of sequential reactions that occur at the solid-fluid interface, has important implications for the corrosion resistance of industrial and nuclear waste glasses. In this study, spectroscopic measurements, dissolution experiments, and Monte Carlo simulations were performed to investigate the effect of high–valence cations (HVC) on the mechanisms of glass dissolution under dilute and near-saturated conditions. Raman and NMR spectroscopy were used to determine the structural changes that occur in glass, specifically network formers (e.g., Al, Si, and B), with the addition of the HVC element hafnium in the Na2O–Al2O3–B2O3–HfO2–SiO2 system (e.g., Na/[Al+B] = 1.0 and HfO2/SiO2 from 0.0 to 0.42). Spectroscopic measurements revealed that increasing hafnium content decreases N4 (tetrahedral boron/total boron) and increases the amount of Si—O—Hf moieties in the glass. Results from flow–through experiments conducted under dilute and near–saturated conditions show a decrease of approximately 100× or more in the dissolution rate over the series from 0 to 20 mol% HfO2. Comparing the average steady-state rates obtained under dilute conditions to the rates obtained for near-saturated conditions reveals a divergence in the magnitude between the average steady state rates measured in these different conditions. The reason for this divergence was investigated more thoroughly using Monte Carlo simulations. Simulations indicate that the divergence in glass dissolution behavior under dilute and near-saturated conditions result from the stronger binding of Si sites that deposit on the surface from the influent when Hf is present in the glass. As a result, the residence time at the glass surface of these newly-formed Si sites is longer in the presence of Hf, which increases the density of anchor sites from which altered layers

  4. Modification of magnetic anisotropy in metallic glasses using high-energy ion beam irradiation

    Indian Academy of Sciences (India)

    K V Amrute; U R Mhatre; S K Sinha; D C Kothari; R Nagarajan; D Kanjilal

    2002-05-01

    Heavy ion irradiation in the electronic stopping power region induces macroscopic dimensional change in metallic glasses and introduces magnetic anisotropy in some magnetic materials. The present work is on the irradiation study of ferromagnetic metallic glasses, where both dimensional change and modification of magnetic anisotropy are expected. Magnetic anisotropy was measured using Mössbauer spectroscopy of virgin and irradiated Fe40Ni40B20 and Fe40Ni38Mo4B18 metallic glass ribbons. 90 MeV 127I beam was used for the irradiations. Irradiation doses were 5 × 1013 and 7.5 × 1013 ions/cm2. The relative intensity ratios 23 of the second and third lines of the Mössbauer spectra were measured to determine the magnetic anisotropy. The virgin samples of both the materials display in-plane magnetic anisotropy, i.e., the spins are oriented parallel to the ribbon plane. Irradiation is found to cause reduction in magnetic anisotropy. Near-complete randomization of magnetic moments is observed at high irradiation doses. Correlation is found between the residual stresses introduced by ion irradiation and the change in magnetic anisotropy.

  5. Quasielastic neutron scattering studies on glass-forming ionic liquids with imidazolium cations

    Science.gov (United States)

    Kofu, Maiko; Tyagi, Madhusudan; Inamura, Yasuhiro; Miyazaki, Kyoko; Yamamuro, Osamu

    2015-12-01

    Relaxation processes for imidazolium-based ionic liquids (ILs) were investigated by means of an incoherent quasielastic neutron scattering technique. In order to clarify the cation and anion effects on the relaxation processes, ten samples were measured. For all of the samples, we found three relaxations at around 1 ps, 10 ps, and 100 ps-10 ns, each corresponding to the alkyl reorientation, the relaxation related to the imidazolium ring, and the ionic diffusion. The activation energy (Ea) for the alkyl relaxation is insensitive to both anion and alkyl chain lengths. On the other hand, for the imidazolium relaxation and the ionic diffusion processes, Ea increases as the anion size decreases but is almost independent of the alkyl chain length. This indicates that the ionic diffusion and imidazolium relaxation are governed by the Coulombic interaction between the core parts of the cations (imidazolium ring) and the anions. This is consistent with the fact that the imidazolium-based ILs have nanometer scale structures consisting of ionic and neutral (alkyl chain) domains. It is also found that there is a clear correlation between the ionic diffusion and viscosity, indicating that the ionic diffusion is mainly associated with the glass transition which is one of the characteristics of imidazolium-based ILs.

  6. Quasielastic neutron scattering studies on glass-forming ionic liquids with imidazolium cations

    International Nuclear Information System (INIS)

    Relaxation processes for imidazolium-based ionic liquids (ILs) were investigated by means of an incoherent quasielastic neutron scattering technique. In order to clarify the cation and anion effects on the relaxation processes, ten samples were measured. For all of the samples, we found three relaxations at around 1 ps, 10 ps, and 100 ps-10 ns, each corresponding to the alkyl reorientation, the relaxation related to the imidazolium ring, and the ionic diffusion. The activation energy (Ea) for the alkyl relaxation is insensitive to both anion and alkyl chain lengths. On the other hand, for the imidazolium relaxation and the ionic diffusion processes, Ea increases as the anion size decreases but is almost independent of the alkyl chain length. This indicates that the ionic diffusion and imidazolium relaxation are governed by the Coulombic interaction between the core parts of the cations (imidazolium ring) and the anions. This is consistent with the fact that the imidazolium-based ILs have nanometer scale structures consisting of ionic and neutral (alkyl chain) domains. It is also found that there is a clear correlation between the ionic diffusion and viscosity, indicating that the ionic diffusion is mainly associated with the glass transition which is one of the characteristics of imidazolium-based ILs

  7. Mechanosensory calcium-selective cation channels in epidermal cells

    Science.gov (United States)

    Ding, J. P.; Pickard, B. G.

    1993-01-01

    This paper explores the properties and likely functions of an epidermal Ca(2+)-selective cation channel complex activated by tension. As many as eight or nine linked or linkable equivalent conductance units or co-channels can open together. Open time for co-channel quadruplets and quintuplets tends to be relatively long with millimolar Mg2+ (but not millimolar Ca2+) at the cytosolic face of excised plasma membrane. Sensitivity to tension is regulated by transmembrane voltage and temperature. Under some circumstances channel activity is sychronized in rhythmic pulses. Certain lanthanides and a cytoskeleton-disturbing herbicide that inhibit gravitropic reception act on the channel system at low concentrations. Specifically, ethyl-N-phenylcarbamate promotes tension-dependent activity at micromolar levels. With moderate suction, Gd3+ provided at about 0.5 micromole at the extracellular face of the membrane promotes for several seconds but may then become inhibitory. Provision at 1-2 micromoles promotes and subsequently inhibits more vigorously (often abruptly and totally), and at high levels inhibits immediately. La3+, a poor gravitropic inhibitor, acts similarly but much more gradually and only at much higher concentrations. These properties, particularly these susceptibilities to modulation, indicate that in vivo the mechanosensitive channel must be mechanosensory and mechanoregulatory. It could serve to transduce the shear forces generated in the integrated wall-membrane-cytoskeleton system during turgor changes and cell expansion as well as transducing the stresses induced by gravity, touch and flexure. In so far as such transduction is modulated by voltage and temperature, the channels would also be sensors for these modalities as long as the wall-membrane-cytoskeleton system experiences mechanical stress.

  8. Molecular dynamics study of the influence of mobile cations on the reconstruction of an irradiated silicate glass

    International Nuclear Information System (INIS)

    The effect of ballistic collisions in a simplified nuclear glass was investigated by molecular dynamics. Systematic results were obtained in the 0-16 keV energy range. Following a damage peak, reconstruction of the glass structure was observed in terms of the overall degree of polymerization. The reconstruction was facilitated by the presence of mobile cations. The dynamics of restoration of the SiO4 tetrahedrons during displacement cascades and during the formation of a structure from a random configuration can be fitted to curves corresponding to the same analytic formula. This similarity allowed us to examine the influence of mobile cations (alkalis or alkaline earths) on the formation of SiO4 entities in smaller systems formed from random configurations. The formation rate of SiO4 tetrahedrons accelerates with the Na2O or CaO percentage to reach a maximum rate above about 10 mol% Na2O or CaO. This threshold corresponds to the disappearance in the glass structure of zones comprising a central bridging oxygen surrounded by two first-neighbor bridging oxygen rings. No mixed alkali effect was observed in systems containing both Na and Cs because the formation of SiO4 does not require long-range diffusion of mobile cations

  9. Maitotoxin activates cation channels distinct from the receptor-activated non-selective cation channels of HL-60 cells

    OpenAIRE

    Musgrave, I. F.; Seifert, Roland; Schultz, Günter

    1994-01-01

    We investigated whether maitotoxin activates non-selective cation channels, as was recently proposed [Soergel, Yasumoto, Daly and Gusovsky (1992) Mol. Pharmacol. 41, 487-493]. Stimulation of dibutyryl cyclic AMP-differentiated HL-60 cells with the chemotactic peptide N-formyl-L-methionyl-L-leucyl-L-phenylalanine (fMLP; 0.1 microM), the Ca(2+)-ATPase inhibitor thapsigargin (0.1 microM) or maitotoxin (25 ng/ml) resulted in an increase in cytoplasmic free calcium concentration ([Ca2+]i). Unlike ...

  10. Inward Cationic Diffusion and Formation of Silica-Rich Surface Nanolayer of Glass

    DEFF Research Database (Denmark)

    Smedskjær, Morten Mattrup; Deubener, Joachim; Yue, Yuanzheng

    2009-01-01

    surface to the interior of the glass. The inward diffusion is induced by the reduction of V5+ to V4+ ions, when the glass is heat-treated in H2/N2 (1/99 v/v) at the glass transition temperature (Tg) for certain durations (ta). During the reduction of vanadium by H2, structurally bonded hydroxyl groups...

  11. Electromagnetic Properties of Substituted Ba - Ferrites by Selected Cations

    Directory of Open Access Journals (Sweden)

    Anna Gruskova

    2004-01-01

    Full Text Available The powdered samples of barium hexaferrite BaFe12-2x(Me1Me2 with x varying from 0.0 to 0.6 were prepared by citrate precursor method. The cation preference of mainly four-valence Me1=(Zr, Ti, Sn ions and two-valence Me2=(Co, Ni, Zn ions and their combinations in substituted Ba ferrites were investigated by the thermomagnetic analysis, Mossbauer spectroscopy and measurement of the magnetic properties. Mossbaur studies reveal that Zr4+, Sn4+ and less Co2+, Zn2+ ions have a strong preference to occupy 2b position, this position has the greatest contribution to the magnetocrystalline anisotropy. The La3+, Ti4+, Ni2+ ions preferently enter 4f2 sites and Zn2+, Co2+ ions also prefer to occupy 4f1 tetrahedral sites. The specific saturation magnetic polarisation Js-m and remanence Js-r increased with small x due to th substitution of non-magnetic and less magnetic ions in 4f1 and 4f2 sites. The coercivity Hc was casily controllable by the sustituions level x.

  12. Selective separation of actinyl(V,VI) cations from aqueous solutions by Chelex-100

    Energy Technology Data Exchange (ETDEWEB)

    Kiliari, T.; Pashalidis, I. [Cyprus Univ., Nicosia (Cyprus). Chemistry Dept.

    2012-07-01

    Experimental studies on the selectivity of Chelex-100 resin for the separation of actinide cations at different oxidation states (III, IV, V and VI) from aqueous solution have shown that Chelex-100 presents increased selectivity for actinyl cations at near neutral pH (pH {proportional_to} 4.5). The effect of salinity on the chemical recovery indicates that the increased selectivity could be attributed to the formation of complexes with specific interactions and the pH area, in which the formation of the respective complexes is favored, indicates the occurrence of guest-host interactions. The specific interaction of Chelex-100 with actinyl cations could be of particular interest not only for the separation and preconcentration of uranium from natural waters prior its analysis but also for the recovery of uranium from seawater on a large scale. (orig.)

  13. Ion-Selective Detection with Glass Nanopipette for Living Cells

    Science.gov (United States)

    Takami, T.; Son, J. W.; Kang, E. J.; Deng, X. L.; Kawai, T.; Lee, S.-W.; Park, B. H.

    2013-05-01

    We developed a method to probe local ion concentration with glass nanopipette in which poly(vinyl chloride) membrane containing ionophore for separate ion detection is prepared. Here we demonstrate how ion-selective detections are available for living cells such as HeLa cell, rat vascular myocyte, and neuron cell.

  14. Electronic spectra of isolated cations in supersonic jets by mass-selected ion-dip spectroscopy. Cations of benzene, p-difluorobenzene, and 1,3,5-trifluorobenzene

    Science.gov (United States)

    Tsuchiya, Yuko; Fujii, Masaaki; Ito, Mitsuo

    1989-06-01

    The electronic transitions of the cations of benzene, p-difluorobenzene (p-DFB), and 1,3,5-trifluorobenzene (1,3,5-TFB) have been measured by mass-selected ion-dip spectroscopy which utilizes the dissociation of a parent cation in an excited state. This spectroscopy was successfully applied to the vibrational level selected cation in the ground electronic state which was prepared by 1+1 REMPI (resonant enhanced multiphoton ionization) of the neutral molecule in a supersonic jet. For all the cations, the spectra due to the transition from the ground state to the excited π,π state were observed. Ion-dip spectra having sharp vibrational structures were found for p-DFB and 1,3,5-TFB cations, while a broad spectrum was observed for a benzene cation. It was also found that the vibrational structure of the ion-dip spectrum of the 1,3,5-TFB cation is quite different from that of the fluorescence excitation spectrum. The assignments of the ion-dip spectra and dissociation mechanisms of the excited cations will be discussed.

  15. Selective Cation Recognition by p-Tetranitrocalix[4]arene

    Directory of Open Access Journals (Sweden)

    M. I. Bhanger

    2012-12-01

    Full Text Available The present study explores the copper selective complexation character of 5,11,17,23-tetranitro-25,26,27,28-tetrahydroxycalix[4]arene (p-TNC4 among a series of different alkali, alkaline earth and transition metal ions, i.e. Li+, Na+, K+,Cs+ Mg2+, Ba2+, Hg2+, Cd2+, Pb2+, Co2+ Ni2+ and Zn2+ using absorption spectroscopic technique. p-TNC4 shows pronounced discriminative specificity towards Cu2+ even the interference study of other co-existing ions also proved this selectivity. Furthermore, the solvatochromic effect, effect of acid (acetic acid, alkali (piperidine on spectra, response time measurement and the stability of p-TNC4-Cu2+ complex in MeCN has also been investigated. The stoichiometric analysis (i.e. Jobs plot reveals that p-TNC4 forms 1:1 host-guest complex with Cu2+.

  16. Selective adsorption of cationic dyes by UiO-66-NH2

    International Nuclear Information System (INIS)

    Graphical abstract: - Highlights: • Two Zr(IV)-based MOFs can remove cationic dyes more effectively than anionic dyes. • UiO-66 has higher selectivity for cationic dyes after modification with NH2. • The mechanism for adsorption selectivity is rationally proposed. - Abstract: Herein, two zirconium(IV)-based MOFs UiO-66 and UiO-66-NH2 had been successfully prepared by a facile solvothermal method and were characterized by X-ray diffraction (XRD), field emission transmission electron microscopy (FETEM), N2 adsorption–desorption (BET), X-ray photoelectron spectroscopy (XPS), and zeta potential. They exhibit small size, large surface area, and can remove cationic dyes from aqueous solution more effectively than anionic dyes. This adsorption selectivity is due to the favorable electrostatic interactions between the adsorbents and cationic dyes. Furthermore, owing to the individual micropore structure of UiO-66-NH2 and its more negative zeta potential resulted from the charge balance for the protonation of –NH2, UiO-66-NH2 displays much higher adsorption capacity for cationic dyes and lower adsorption capacity for anionic dyes than UiO-66

  17. Selective adsorption of cationic dyes by UiO-66-NH{sub 2}

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Qi; He, Qinqin; Lv, Mengmeng; Xu, Yanli; Yang, Hanbiao; Liu, Xueting, E-mail: wmlxt@163.com; Wei, Fengyu, E-mail: weifyliuj@163.com

    2015-02-01

    Graphical abstract: - Highlights: • Two Zr(IV)-based MOFs can remove cationic dyes more effectively than anionic dyes. • UiO-66 has higher selectivity for cationic dyes after modification with NH{sub 2}. • The mechanism for adsorption selectivity is rationally proposed. - Abstract: Herein, two zirconium(IV)-based MOFs UiO-66 and UiO-66-NH{sub 2} had been successfully prepared by a facile solvothermal method and were characterized by X-ray diffraction (XRD), field emission transmission electron microscopy (FETEM), N{sub 2} adsorption–desorption (BET), X-ray photoelectron spectroscopy (XPS), and zeta potential. They exhibit small size, large surface area, and can remove cationic dyes from aqueous solution more effectively than anionic dyes. This adsorption selectivity is due to the favorable electrostatic interactions between the adsorbents and cationic dyes. Furthermore, owing to the individual micropore structure of UiO-66-NH{sub 2} and its more negative zeta potential resulted from the charge balance for the protonation of –NH{sub 2}, UiO-66-NH{sub 2} displays much higher adsorption capacity for cationic dyes and lower adsorption capacity for anionic dyes than UiO-66.

  18. Gamma Ray Attenuation Coefficient And Durability Of Some Iron-Sodium-Phosphate Glasses Doped With Ba2+ Cations

    International Nuclear Information System (INIS)

    Glasses with the nominal composition (65-x) mol% P2O5 + 15 mol% Fe2O3 + 20 mol% Na2O + x mol% BaO (where 0 ≤ x ≤ 25) have been prepared by the conventional melt quenching technique. The amorphous nature of the obtained samples was confirmed by using XRD analysis, and the structural groups composing the network were investigated by FTIR spectroscopy. It was found that phosphorus and most iron cations participate as glass network formers (GNF) while sodium and barium participate as glass network modifiers (GNM) occupying the interstitial vacancies in the glass network. As BaO was gradually increased, the density and gamma ray mass attenuation coefficient of the studied samples were found to increased while the dissolution rate and the half value layer showed gradual decrease. It is recommended that the samples containing high BaO concentrations can be used as shield from harmful rays as well as for encapsulating radioactive wastes before underground disposal, especially the sample that contains 25 mol % BaO.

  19. Experimental Investigation on Selective Laser Melting of Glass

    Science.gov (United States)

    Fateri, Miranda; Gebhardt, Andreas; Thuemmler, Stefan; Thurn, Laura

    Although laser-based Additive Manufacturing (AM) processes have been investigated extensively for use with different materials, fabrication of 3D glass objects using Selective Laser Melting (SLM) technology is not well developed even though it has many applications. As such an experimental investigation on the process parameters of glass powder using SLM process was conducted and the results are summarized in this paper. Multiple 3D objects were fabricated and analyzed. Lastly Scanning Electron Microcopy (SEM) of the manufactured objects as well as effect of process parameters on dimensional accuracy, surface quality, and the density of the fabricated parts are presented in this paper.

  20. Synthetic crystalline calcium silicate hydrate (I): cation exchange and caesium selectivity

    International Nuclear Information System (INIS)

    Solid crystalline calcium silicate hydrate (I) synthesized from equimolar amounts of Ca and Si under hydrothermal conditions at 120 oC shows cation exchange properties towards divalent metal cations such as Ni, Cu, Cd, or Hg. It also exhibits caesium selectivity in the presence of Na+. The exchange capacity and selectivity of the solid can be increased by 10 and 28 %, respectively, upon substitution of 0.01 mol of the Ca2+ in its structure by Na+. The ability of metal cation uptake by the solid was found to obey the order Ni2+ > Hg2+ > Cu2+ > Cd2+. The different affinities of calcium silicate hydrate (I) towards these ions can be used for their separation from solutions and also in nuclear waste treatment. The mechanism of the exchange reaction is discussed. (author)

  1. Spectrally selective coatings of gold nanorods on architectural glass

    International Nuclear Information System (INIS)

    Infrared-blocking coatings on window glass can be produced by dispersing gold nanorods into a polymer coating. The spectral selectivity of the coating is controlled by the shape and aspect ratio of the nanoparticles, which are in turn determined by the conditions applied during their synthesis. Coatings of nanorods in polyvinyl alcohol were deposited onto glass and characterized in both laboratory and sun-lit conditions. Selective attenuation of the near-infrared was demonstrated with the test panels transmitting approximately one-third of the incident solar radiation and absorbing nearly two-thirds. The high absorptive cross sections of the gold nanorods suggest that they can be applied in efficacious coatings at relatively low volume fractions.

  2. The Effect of Head-Group on Selective Counterion Binding to Cationic Surfactants

    Science.gov (United States)

    Kellaway; Warr

    1997-09-15

    Selectivity coefficients for the competitive adsorption of chloride, bromide, and iodide at the air/solution interface have been measured by a high accuracy ion flotation technique using the surfactant cations dodecylammonium, dodecylmethylammonium, dodecyldimethylammonium, and dodecyltrimethylammonium. Selective binding was found to depend on the nature of the head group, with selectivity increasing from primary to quaternary ammonium ions. Results are consistent with counterion binding arising from contact adsorption by mutual dehydration of head groups and counterions. Copyright 1997 Academic Press. Copyright 1997Academic Press PMID:9344533

  3. Tuning the ion selectivity of tetrameric cation channels by changing the number of ion binding sites

    Energy Technology Data Exchange (ETDEWEB)

    Derebe, Mehabaw G.; Sauer, David B.; Zeng, Weizhong; Alam, Amer; Shi, Ning; Jiang, Youxing (UTSMC); (ETH Zurich)

    2015-11-30

    Selective ion conduction across ion channel pores is central to cellular physiology. To understand the underlying principles of ion selectivity in tetrameric cation channels, we engineered a set of cation channel pores based on the nonselective NaK channel and determined their structures to high resolution. These structures showcase an ensemble of selectivity filters with a various number of contiguous ion binding sites ranging from 2 to 4, with each individual site maintaining a geometry and ligand environment virtually identical to that of equivalent sites in K{sup +} channel selectivity filters. Combined with single channel electrophysiology, we show that only the channel with four ion binding sites is K{sup +} selective, whereas those with two or three are nonselective and permeate Na{sup +} and K{sup +} equally well. These observations strongly suggest that the number of contiguous ion binding sites in a single file is the key determinant of the channel's selectivity properties and the presence of four sites in K{sup +} channels is essential for highly selective and efficient permeation of K{sup +} ions.

  4. Revisiting benzene cluster cations for the chemical ionization of dimethyl sulfide and select volatile organic compounds

    Science.gov (United States)

    Kim, Michelle J.; Zoerb, Matthew C.; Campbell, Nicole R.; Zimmermann, Kathryn J.; Blomquist, Byron W.; Huebert, Barry J.; Bertram, Timothy H.

    2016-04-01

    Benzene cluster cations were revisited as a sensitive and selective reagent ion for the chemical ionization of dimethyl sulfide (DMS) and a select group of volatile organic compounds (VOCs). Laboratory characterization was performed using both a new set of compounds (i.e., DMS, β-caryophyllene) as well as previously studied VOCs (i.e., isoprene, α-pinene). Using a field deployable chemical-ionization time-of-flight mass spectrometer (CI-ToFMS), benzene cluster cations demonstrated high sensitivity (> 1 ncps ppt-1) to DMS, isoprene, and α-pinene standards. Parallel measurements conducted using a chemical-ionization quadrupole mass spectrometer, with a much weaker electric field, demonstrated that ion-molecule reactions likely proceed through a combination of ligand-switching and direct charge transfer mechanisms. Laboratory tests suggest that benzene cluster cations may be suitable for the selective ionization of sesquiterpenes, where minimal fragmentation (validated against an atmospheric pressure ionization mass spectrometer, where measurements from the two instruments were highly correlated (R2 > 0.95, 10 s averages) over a wide range of sampling conditions.

  5. A cationic surfactant assisted selective etching strategy to hollow mesoporous silica spheres.

    Science.gov (United States)

    Fang, Xiaoliang; Chen, Cheng; Liu, Zhaohui; Liu, Pengxin; Zheng, Nanfeng

    2011-04-01

    Hollow mesoporous silica spheres have recently attracted increasing attention. However, effective synthesis of uniform hollow mesoporous spheres with controllable well-defined pore structures for fundamental research and practical applications has remained a significant challenge. In this work, a straightforward and effective "cationic surfactant assisted selective etching" synthetic strategy was developed for the preparation of high-quality hollow mesoporous silica spheres with either wormhole-like or oriented mesoporous shell. The as-prepared hollow mesoporous silica spheres have large surface area, high pore volume, and controllable structure parameters. Our experiments demonstrated that cationic surfactant plays critical roles in forming the hollow mesoporous structure. A formation mechanism involving the etching of solid SiO(2) accelerated by cationic surfactant followed by the redeposition of dissolved silica species directed by cationic surfactant is proposed. Furthermore, the strategy can be extended as a general strategy to transform silica-coated composite materials into yolk-shell structures with either wormhole-like or oriented mesoporous shell. PMID:21305093

  6. Glass nanopore-based ion-selective electrodes.

    Science.gov (United States)

    Shim, Jun Ho; Kim, Juneho; Cha, Geun Sig; Nam, Hakhyun; White, Ryan J; White, Henry S; Brown, Richard B

    2007-05-15

    Glass nanopore-based all-solid-state ion-selective electrodes (ISEs) have been developed to probe the distribution of ionic species at micro- or submicrometer-length scales, e.g., mapping of ion flux through micrometer-sized pores. The all-solid-state ISE was fabricated by sealing a conically etched platinum wire (d = 25-microm; radius of etched tip scanning electrochemical microscope experiments to map the ion flux through a micropore. The same ISE was also used as the base transducer of the neutral carrier-doped solvent polymeric membrane. The optimized polymer membranes used for the glass nanopore-based all-solid-state ISE require a higher ratio of plasticizer/polymer (9/1) compared to those for conventional ISE (2/1). An ISE based on deposition of an IrO2 layer at the base of a glass nanopore electrode exhibited a highly sensitive response (79.7 +/- 2.3 mV/pH) to variations in pH and could be used for approximately 3 weeks. PMID:17411008

  7. Selective separation of sodium ions from a mixture with phenylalanine by Donnan dialysis with a profiled sulfogroup cation exchange membrane

    Science.gov (United States)

    Vasil'eva, V. I.; Goleva, E. A.

    2013-11-01

    The possibility of separating ions of metal from a mixture with ampholyte (an amino acid) by Donnan dialysis with an MK-40 sulfogroup cation exchange membrane is demonstrated. Conditions ensuring the selectivity and intensity of the mass transfer of sodium ions from a mixture with bipolar phenylalanine ions into a diffusate containing hydrochloric acid through a cation exchange membrane are found.

  8. Preparation of titanium peroxide and its selective adsorption property on cationic dyes

    International Nuclear Information System (INIS)

    Titanium peroxide powder was prepared with the reaction of titanium sulfate and H2O2 and showed good selective adsorption property on cationic dyes. The obtained material was characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FT-IR), X-ray photoelectron spectroscopy (XPS) and thermogravimetric and differential scanning calorimetry (TG-DSC). The selective adsorption property was confirmed and evaluated by adsorption experiments of methyl orange (MO), phenol and three kinds of cationic dyes including methylene blue (MB), malachite green (MG) and neutral red (NR). The adsorption was very fast and adsorption equilibrium was reached in a very short time for all three cationic dyes. The adsorption kinetics of MB, MG and NR were studied then. It was found that the adsorption data fitted perfectly with the pseudo-second-order kinetics and the saturated adsorption capacities for MB, MG and NR were 224.37, 251.38 and 327.61 mg/g at 25 °C, respectively. The characterization and adsorption results indicated the controlling mechanism of adsorption processes could be electrostatic adsorption.

  9. Selecting Glass Window with Film for Buildings in a Hot Climate

    OpenAIRE

    Nopparat Khamporn; Somsak Chaiyapinunt

    2009-01-01

    This article is about the developing parameters and relationships for selecting a proper glass window applied with film as building envelopes for buildings located in a hot climate based on its thermal performances. Thermal comfort of the occupants sitting near the glass window is the thermal performance that needed to be considered besides the heat transmission in selecting a proper type of glass to use as a glass window for the building. The predicted percentage of dissatisfied (PPD) is cho...

  10. Diphtheria toxin-induced channels in Vero cells selective for monovalent cations

    Energy Technology Data Exchange (ETDEWEB)

    Sandvig, K.; Olsnes, S.

    1988-09-05

    Ion fluxes associated with translocation of diphtheria toxin across the surface membrane of Vero cells were studied. When cells with surface-bound toxin were exposed to low pH to induce toxin entry, the cells became permeable to Na+, K+, H+, choline+, and glucosamine+. There was no increased permeability to Cl-, SO4(-2), glucose, or sucrose, whereas the uptake of /sup 45/Ca2+ was slightly increased. The influx of Ca2+, which appears to be different from that of monovalent cations, was reduced by several inhibitors of anion transport and by verapamil, Mn2+, Co2+, and Ca2+, but not by Mg2+. The toxin-induced fluxes of N+, K+, and protons were inhibited by Cd2+. Cd2+ also protected the cells against intoxication by diphtheria toxin, suggesting that the open cation-selective channel is required for toxin translocation. The involvement of the toxin receptor is discussed.

  11. Selective laser densification of lithium aluminosilicate glass ceramic tapes

    International Nuclear Information System (INIS)

    Highlights: ► Selective laser densification of glass-ceramic tapes has been investigated. ► A possible application to the layerwise-slurry deposition process was evaluated. ► The effect of a few percent organic in the slurry was also studied. ► A range of parameters was identified to densify layers without macroscopic defects. - Abstract: Tapes, cast by blade deposition of a lithium aluminosilicate glass slurry, were sintered using a YAG-fiber laser, with the aim of finding suitable parameters for an additive manufacturing process based on layer-wise slurry deposition and selective laser densification. The influence of the laser parameters (output power and scan velocity) on the sintering was evaluated, by scanning electron microscopy and by X-ray diffraction, on the basis of the quality of the processed layer. Well densified samples could be obtained only in a small window of values for the output power and the scan velocity. The measurement of the width of a set of single scanned lines allowed also to estimate the minimum resolution of the system along the layer plane.

  12. Reverse aggregates as adaptive self-assembled systems for selective liquid-liquid cation extraction

    International Nuclear Information System (INIS)

    Separation of metals in the cationic form is the basis of hydrometallurgy. Ion-specific separation is achieved via selective transfer between liquid phases that have been emulsified in order to be in 'close' contact. We show here how the organization of water-in-oil (w/o) 'reverse' aggregates in the solvent phase controls the free energy of transfer of cations in the form of neutral salts between phases. Indeed, all known efficient ion separation mechanisms rely on complex fluids in the Winsor II regime, i.e. when a concentrated mixed salt solution is in equilibrium with a solvent phase containing self-assembled aggregates. Here, we point out that, in the general case of water-poor complex fluids containing extractant molecules, long-range interactions linked to w/o interface curvature participate in the selectivity of any multivalent ion extraction process. The free energy related to ion transfer between phases, i.e. the extraction free energy, is different from the complexation free energy. This difference is the key to the selectivity of the separation process. We give here general expressions linking complexation free energy and transfer free energy as derived from known adsorption isotherms, taking into account interfacial curvature, considered as a generalized scalar related to the packing near the interface. (authors)

  13. 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.

  14. Infrared Photodissociation Spectra of Mass-Selected Homoleptic Dinuclear Palladium Carbonyl Cluster Cations in the Gas Phase

    Institute of Scientific and Technical Information of China (English)

    崔洁铭; 邢小鹏; 池超贤; 王冠军; 刘智攀; 周鸣飞

    2012-01-01

    Infrared spectra of mass-selected homoleptic dinuclear palladium carbonyl cluster cations Pd2(CO)n (n=5 8) are measured via infrared photodissociation spectroscopy in the carbonyl stretching frequency region. The structures are established by comparison of the experimental spectra with simulated spectra derived from density functional calculations. The Pd2(CO)+ cation is characterized to have two weakly semibridging CO groups with C2 symmetry. The Pd2(CO)6+ and Pd2(CO)7+ cations are determined to involve one weakly semibridging CO group. The Pd2(CO)8+ cation is a CO coordination saturated cluster, which is determined to have a D2d structure with all of the carbonyl groups terminally bonded. Bonding analysis indicates that these cluster cations each has a Pd--Pd half bond. The Pd--Pd distance increases with the number of CO ligands.

  15. STRESS RELAXATION CHARACTERISTICS OF SELECTED COMMERCIALLY PRODUCED GLASSES

    Directory of Open Access Journals (Sweden)

    Chocholoušek J.

    2013-06-01

    Full Text Available This paper describes a quantitative method of stress relaxation measurement in prismatic glass samples during two different time-temperature regimes using the Sénarmont compensator. Four types of glass (Barium crystal glass, Eutal, Simax, and Container glass were subjected to observation in an assembled measuring device. Results will be used for parameterization of the Tool-Narayanaswamy-Mazurin model and consequently implemented in a finite element method code.

  16. Calcium sensitive non-selective cation current promotes seizure-like discharges and spreading depression in a model neuron

    NARCIS (Netherlands)

    G.G. Somjen; H. Kager; W.J. Wadman

    2009-01-01

    As described by others, an extracellular calcium-sensitive non-selective cation channel ([Ca(2+)](o)-sensitive NSCC) of central neurons opens when extracellular calcium level decreases. An other non-selective current is activated by rising intracellular calcium ([Ca(2+)]( i )). The [Ca(2+)](o)-sensi

  17. Cation-selective transporters are critical to the AMPK-mediated antiproliferative effects of metformin in human breast cancer cells.

    Science.gov (United States)

    Cai, Hao; Zhang, Yunhui; Han, Tianxiang Kevin; Everett, Ruth S; Thakker, Dhiren R

    2016-05-01

    The antidiabetic drug metformin exerts antineoplastic effects against breast cancer and other cancers. One mechanism by which metformin is believed to exert its anticancer effect involves activation of its intracellular target, adenosine monophosphate-activated protein kinase (AMPK), which is also implicated in the antidiabetic effect of metformin. It is proposed that in cancer cells, AMPK activation leads to inhibition of the mammalian target of rapamycin (mTOR) and the downstream pS6K that regulates cell proliferation. Due to its hydrophilic and cationic nature, metformin requires cation-selective transporters to enter cells and activate AMPK. This study demonstrates that expression levels of cation-selective transporters correlate with the antiproliferative and antitumor efficacy of metformin in breast cancer. Metformin uptake and antiproliferative activity were compared between a cation-selective transporter-deficient human breast cancer cell line, BT-20, and a BT-20 cell line that was engineered to overexpress organic cation transporter 3 (OCT3), a representative of cation-selective transporters and a predominant transporter in human breast tumors. Metformin uptake was minimal in BT-20 cells, but increased by >13-fold in OCT3-BT20 cells, and its antiproliferative potency was >4-fold in OCT3-BT20 versus BT-20 cells. This increase in antiproliferative activity was associated with greater AMPK phosphorylation and decreased pS6K phosphorylation in OCT3-BT20 cells. In vitro data were corroborated by in vivo observations of significantly greater antitumor efficacy of metformin in xenograft mice bearing OCT3-overexpressing tumors versus low transporter-expressing wildtype tumors. Collectively, these findings establish a clear relationship between cation-selective transporter expression, the AMPK-mTOR-pS6K signaling cascade, and the antiproliferative activity of metformin in breast cancer. PMID:26669511

  18. Aluminium and hydrogen ions inhibit a mechanosensory calcium-selective cation channel

    Science.gov (United States)

    Ding, J. P.; Pickard, B. G.

    1993-01-01

    The tension-dependent activity of mechanosensory calcium-selective cation channels in excised plasmalemmal patches from onion bulb scale epidermis is modulated by pH in the physiologically meaningful range between 4.5 and 7.2. It is rapidly lowered by lowering pH and rapidly raised by raising pH. Channel activity is effectively inhibited by low levels of aluminium ions and activity can be partially restored by washing for a few minutes. We suggest that under normal conditions the sensitivity of the mechanosensory channels to pH of the wall free space plays important roles in regulation of plant activities such as growth. We further suggest that, when levels of acid and aluminium ions in the soil solution are high, they might inhibit similar sensory channels in cells of the root tip, thus contributing critically to the acid soil syndrome.

  19. Latent image generation by soft landing of size-selected silver cluster cations

    International Nuclear Information System (INIS)

    We investigate the role of silver clusters in the photographic latent image generation. Silver cluster cations were produced in a sputtering arrangement, mass selected by a quadrupole mass filter and deposited with a well controlled kinetic energy onto photographic silver bromide crystals. The fraction of developed crystals after exposure of the samples to photographic developer was measured as a function of the size of the deposited clusters, the cluster coverage, the kinetic energy of the clusters, and the redox-potential of the developer. Development was observed after deposition of Ag4+ or larger aggregates, and, to a much lower extend, after deposition of the trimer. Silver monomers and dimers showed no photographic effect. Our data confirm that silver clusters above a critical size, which depends on the redox-potential of the developer, form the latent image in photography. (author)

  20. Analyses of tobacco alkaloids by cation-selective exhaustive injection sweeping microemulsion electrokinetic chromatography.

    Science.gov (United States)

    Huang, Hsi-Ya; Hsieh, Shih-Huan

    2007-09-14

    In this study, an on-line concentration method which coupled cation-selective exhaustive injection (CSEI) sweeping technology with microemulsion electrokinetic chromatography (MEEKC) was used to detect and analyze several tobacco alkaloids (nornicotine, anabasine, anatabine, nicotine, myosmine and cotinine) that are commonly found in various tobacco products. First, the effects of microemulsion compositions (oil, cosurfactant and solution pH) were examined in order to optimize the alkaloid separations in conventional MEEKC. The pH value and the injection length of basic plug were found to be the predominant influences on the alkaloid stacking. This optimal CSEI sweeping MEEKC method provided approximately 180- to 540-fold increase in detection sensitivity in terms of peak height without any loss in separation efficiency when compared to normal MEEKC separation. Furthermore, this proposed CSEI sweeping MEEKC method was applied successfully for the detection of the minor alkaloids nornicotine, anabasine and anatabine in tobacco products. PMID:17644105

  1. On the Possibility of Selective Laser Melting of Quartz Glass

    Science.gov (United States)

    Khmyrov, R. S.; Grigoriev, S. N.; Okunkova, A. A.; Gusarov, A. V.

    Quartz glass is considered as model ceramic material for selective laser melting (SLM). Single beads of fused powder bonded with a continuous substrate of the same material are obtained. Neither the beads nor the substrates near them are cracked. Low closed porosity in the beads and detachment of the bead borders from the substrate are observed. The quality of the obtained beads is estimated to be sufficient for fabrication of three-dimensional parts by SLM. Comparison with calculations of heat transfer and evaporation reveals that the mass and the energy losses by evaporation are considerable and that the substrate surface should be locally heated up to 1600 K for strong bonding with the bead. Decreasing the thickness of the deposited powder layer is proposed to improve the adhesion between the bead and the substrate with the minimum loss in the productivity of the process. Finer powder is expected to decrease the residual closed porosity in the bead and to make the pores finer too.

  2. Qualitative and quantitative analysis of cations and anions using ion selective detectors in capillary electrophoresis

    International Nuclear Information System (INIS)

    The present work reports on the application of ion-selective microelectrodes as potentiometric detectors for the qualitative and quantitative analysis of cations and anions separated by capillary electrophoresis. Due to the high internal resistance of microelectrodes, their potentials are strongly affected by external electrical fields. Therefore, the influence of the electrophoretic field on the electrode response had to be kept at a minimum. With the electrode tip inserted in the capillary aperture (on-column detection), heavy drifts and noise of the signals were observed, mainly because the electrophoretic potential is superimposed on the Nernstian electrode response. As the potential inside the capillary is site-dependent, already minor movements and vibrations not perceptible under the light microscopy cause unacceptable disturbances of the electrode signal. One possibility to solve the problem consists in post- or off-column detection, i.e., with the detector located outside the influence of the electrophoretic field. If quantitative analyses with maximum resolution are to be achieved, only on-column detection is suitable because outside the capillary, the separation efficiency drops drastically. By etching the detector-side capillary end to a conical aperture, the field strength in the last 10 μm fell approximately 1/25 as compared with that in a cylindrical one. Thus, potential drifts and noise were reduced correspondingly so that on-column detection can also be used for potentiometric detection. To obtain quantitative results, the signals of the ion-selective detector were first delogarithmized and then integrated over time. Thus, it was possible to quantify cations and anions with a coefficient of variations ≤5%. (author) figs., tabs., 179 refs

  3. Selecting Glass Window with Film for Buildings in a Hot Climate

    Directory of Open Access Journals (Sweden)

    Nopparat Khamporn

    2009-02-01

    Full Text Available This article is about the developing parameters and relationships for selecting a proper glass window applied with film as building envelopes for buildings located in a hot climate based on its thermal performances. Thermal comfort of the occupants sitting near the glass window is the thermal performance that needed to be considered besides the heat transmission in selecting a proper type of glass to use as a glass window for the building. The predicted percentage of dissatisfied (PPD is chosen as a thermal comfort index. 45 types of film and 1280 glass windows with film are investigated in this study. It can be shown that the thermal comfort index is dependent on the optical properties (total transmittance and total absorptance and the overall heat transfer coefficient of glass windows with film. Glass window with film which has high transmittance shall have more discomfort due to solar radiation effect. Glass window with film which has high absorptance shall have more discomfort due to surface temperature effect. The discomfort from the surface temperature effect for double pane glass window with film is also dependent on the glass thickness other than the absorptance and the change in overall heat transfer coefficient. Expressions for predicting the performance of the glass windows with film in terms of thermal comfort are developed.

  4. Selectivity of externally facing ion-binding sites in the Na/K pump to alkali metals and organic cations.

    Science.gov (United States)

    Ratheal, Ian M; Virgin, Gail K; Yu, Haibo; Roux, Benoît; Gatto, Craig; Artigas, Pablo

    2010-10-26

    The Na/K pump is a P-type ATPase that exchanges three intracellular Na(+) ions for two extracellular K(+) ions through the plasmalemma of nearly all animal cells. The mechanisms involved in cation selection by the pump's ion-binding sites (site I and site II bind either Na(+) or K(+); site III binds only Na(+)) are poorly understood. We studied cation selectivity by outward-facing sites (high K(+) affinity) of Na/K pumps expressed in Xenopus oocytes, under voltage clamp. Guanidinium(+), methylguanidinium(+), and aminoguanidinium(+) produced two phenomena possibly reflecting actions at site III: (i) voltage-dependent inhibition (VDI) of outwardly directed pump current at saturating K(+), and (ii) induction of pump-mediated, guanidinium-derivative-carried inward current at negative potentials without Na(+) and K(+). In contrast, formamidinium(+) and acetamidinium(+) induced K(+)-like outward currents. Measurement of ouabain-sensitive ATPase activity and radiolabeled cation uptake confirmed that these cations are external K(+) congeners. Molecular dynamics simulations indicate that bound organic cations induce minor distortion of the binding sites. Among tested metals, only Li(+) induced Na(+)-like VDI, whereas all metals tested except Na(+) induced K(+)-like outward currents. Pump-mediated K(+)-like organic cation transport challenges the concept of rigid structural models in which ion specificity at site I and site II arises from a precise and unique arrangement of coordinating ligands. Furthermore, actions by guanidinium(+) derivatives suggest that Na(+) binds to site III in a hydrated form and that the inward current observed without external Na(+) and K(+) represents cation transport when normal occlusion at sites I and II is impaired. These results provide insights on external ion selectivity at the three binding sites. PMID:20937860

  5. Glass and Glass-Ceramic Materials from Simulated Composition of Lunar and Martian Soils: Selected Properties and Potential Applications

    Science.gov (United States)

    Ray, C. S.; Sen, S.; Reis, S. T.; Kim, C. W.

    2005-01-01

    In-situ resource processing and utilization on planetary bodies is an important and integral part of NASA's space exploration program. Within this scope and context, our general effort is primarily aimed at developing glass and glass-ceramic type materials using lunar and martian soils, and exploring various applications of these materials for planetary surface operations. Our preliminary work to date have demonstrated that glasses can be successfully prepared from melts of the simulated composition of both lunar and martian soils, and the melts have a viscosity-temperature window appropriate for drawing continuous glass fibers. The glasses are shown to have the potential for immobilizing certain types of nuclear wastes without deteriorating their chemical durability and thermal stability. This has a direct impact on successfully and economically disposing nuclear waste generated from a nuclear power plant on a planetary surface. In addition, these materials display characteristics that can be manipulated using appropriate processing protocols to develop glassy or glass-ceramic magnets. Also discussed in this presentation are other potential applications along with a few selected thermal, chemical, and structural properties as evaluated up to this time for these materials.

  6. Photocontrolled selective isolation of uranyl cation from aqueous solution onto a photo-responsive Langmuir-Blodgett film

    International Nuclear Information System (INIS)

    We applied a photo-responsive Langmuir-Blodgett (LB) film to selective isolation of uranyl cation from aqueous solutions. Uranyl cation was isolated onto a quartz plate covered with 5-octadecyloxy-2-(2-pyridylazo)phenol (PARC18) LB film which possesses the potential to form a complex with transition metal cations. The isolation process could be switched on by photoillumination. On the other hand, lanthanides (La, Ce, Nd, Gd, Er and Yb) were hardly isolated onto this film. Therefore, it was suggested that uranyl can selectively be collected from mixed solutions containing uranyl and lanthanides and that this process can be controlled by photoillumination. Detection limit of uranyl concentration in this system was also determined to be about 1.5 ppb. (author)

  7. Analyses of sulfonamide antibiotics by a successive anion- and cation-selective injection coupled to microemulsion electrokinetic chromatography.

    Science.gov (United States)

    Lin, Yun-Ta; Liu, Yu-Wei; Cheng, Yi-Jie; Huang, Hsi-Ya

    2010-07-01

    In this study, an MEEKC was used to detect and analyze nine sulfonamide antibiotics. Owing to an insufficient sensitivity of on-column UV detection, a field-amplified sample injection, successive anion- and cation-selective injection, was used for the on-line concentration of the nine antibiotics. In the successive anion- and cation-selective injection mode, a leading water plug was introduced prior to anion injection, and then an acidic plug followed by a terminal water plug had to be used before subsequent cation injection. The results indicated some sulfonamides (sulfamonomethoxine, sulfamethazine, sulfamerazine and sulfadiazine) were determined as split signals in pairs, and this was likely due to the use of a longer acid plug (360 s) which caused the sulfonamide anions and cations to be stacked in two distinct zones of the leading water and acid plugs. Meanwhile, all the sulfonamides that were introduced either by anion or cation injection were stacked within the leading water plug when a shorter acid plug (210 s) was used. As a result, the nine sulfonamides were determined as single and symmetrical peaks with low LODs (0.9-4.2 microg/L). Furthermore, the MEEKC method was successfully applied for the detection of trace sulfonamide residues in several food and water samples. PMID:20593402

  8. GLASS SELECTION STRATEGY: DEVELOPMENT OF US AND KRI TEST MATRICIES

    International Nuclear Information System (INIS)

    High-level radioactive wastes are stored as liquids in underground storage tanks at the Department of Energy's (DOE) Savannah River Site (SRS) and Hanford Reservation. These wastes are to be prepared for permanent disposition in a geologic repository by vitrification with glass forming additives (e.g., frit), creating a waste form with long-term durability. Wastes at SRS are being vitrified in the Defense Waste Processing Facility (DWPF). Vitrification of the wastes stored at Hanford is planned for the Waste Treatment and Immobilization Plant (WTP) when completed. Some of the wastes at SRS, and particularly those at Hanford, contain high concentrations of aluminum, chromium and sulfate. These elements make it more difficult to produce a waste glass with a high waste loading (WL) without crystallization occurring in the glass (either within the melter or upon cooling of the glass), potentially exceeding the solubility limit of critical components, having negative impacts on durability, and/or resulting in the formation of a sulfate salt layer on the molten glass surface. Although the overall scope of the task is focused on all three critical, chemical components, the current work will primarily address the potential for crystallization (e.g., nepheline and/or spinel) in high level waste (HLW) glasses. Recent work at the Savannah River National Laboratory (SRNL) and by other groups has shown that nepheline (NaAlSiO4), which is likely to crystallize in high-alumina glasses, has a detrimental effect on the durability of the glass. The objective of this task is to develop glass formulations for specific SRS and Hanford waste streams to avoid nepheline formation while meeting waste loading and waste throughput expectations, as well as satisfying critical process and product performance related constraints. Secondary objectives of this task are to assess the sulfate solubility limit for the DWPF composition and spinel settling for the WTP composition. SRNL has partnered

  9. Mechanism study of femtosecond laser induced selective metallization (FLISM) on glass surfaces

    Science.gov (United States)

    Xu, Jian; Liao, Yang; Zeng, Huidan; Cheng, Ya; Xu, Zhizhan; Sugioka, Koji; Midorikawa, Katsumi

    2008-07-01

    We investigate the mechanism of selective metallization on glass surfaces with the assistance of femtosecond laser irradiation followed by electroless plating. Irradiation of femtosecond laser makes it possible to selectively deposit copper microstructures in the irradiated area on glass surfaces coated with silver nitrate films. The energy-dispersive X-ray (EDX) analyses reveal that silver atoms are produced on the surface of grooves formed by laser ablation, which serve as catalysis seeds for subsequent electroless copper plating.

  10. Energy Saving Glass Lamination via Selective Radio Frequency Heating

    Energy Technology Data Exchange (ETDEWEB)

    Allan, Shawn M; Baranova, Inessa; Poley, Joseph; Reis, Henrique

    2012-02-27

    This project focused on advancing radio-frequency (RF) lamination technology closer to commercial implementation, in order to reduce the energy intensity of glass lamination by up to 90%. Lamination comprises a wide range of products including autoglass, architectural safety and innovative design glass, transparent armor (e.g. bullet proof glass), smart glass, mirrors, and encapsulation of photovoltaics. Lamination is also the fastest growing segment of glass manufacturing, with photovoltaics, architectural needs, and an anticipated transition to laminated side windows in vehicles. The state-of-the-art for glass lamination is to use autoclaves, which apply heat and uniform gas pressure to bond the laminates over the course of 1 to 18 hours. Laminates consist of layers of glass or other materials bonded with vinyl or urethane interlayers. In autoclaving, significant heat energy is lost heating the chamber, pressurized air, glass racks, and the glass. In RF lamination, the heat is generated directly in the vinyl interlayer, causing it to heat and melt quickly, in just 1 to 10 minutes, without significantly heating the glass or the equipment. The main purpose of this project was to provide evidence that low energy, rapid RF lamination quality met the same standards as conventionally autoclaved windows. The development of concepts for laminating curved glass with RF lamination was a major goal. Other primary goals included developing a stronger understanding of the lamination product markets described above, and to refine the potential benefits of commercial implementation. The scope of the project was to complete implementation concept studies in preparation for continuation into advanced development, pilot studies, and commercial implementation. The project consisted of 6 main tasks. The first dealt with lamination with poly-vinyl butyral (PVB) interlayers, which prior work had shown difficulties in achieving good quality laminates, working with Pilkington North

  11. Energy Saving Glass Lamination via Selective Radio Frequency Heating

    Energy Technology Data Exchange (ETDEWEB)

    Allan, Shawn M.

    2012-02-27

    This project focused on advancing radio-frequency (RF) lamination technology closer to commercial implementation, in order to reduce the energy intensity of glass lamination by up to 90%. Lamination comprises a wide range of products including autoglass, architectural safety and innovative design glass, transparent armor (e.g. bullet proof glass), smart glass, mirrors, and encapsulation of photovoltaics. Lamination is also the fastest growing segment of glass manufacturing, with photovoltaics, architectural needs, and an anticipated transition to laminated side windows in vehicles. The state-of-the-art for glass lamination is to use autoclaves, which apply heat and uniform gas pressure to bond the laminates over the course of 1 to 18 hours. Laminates consist of layers of glass or other materials bonded with vinyl or urethane interlayers. In autoclaving, significant heat energy is lost heating the chamber, pressurized air, glass racks, and the glass. In RF lamination, the heat is generated directly in the vinyl interlayer, causing it to heat and melt quickly, in just 1 to 10 minutes, without significantly heating the glass or the equipment. The main purpose of this project was to provide evidence that low energy, rapid RF lamination quality met the same standards as conventionally autoclaved windows. The development of concepts for laminating curved glass with RF lamination was a major goal. Other primary goals included developing a stronger understanding of the lamination product markets described above, and to refine the potential benefits of commercial implementation. The scope of the project was to complete implementation concept studies in preparation for continuation into advanced development, pilot studies, and commercial implementation. The project consisted of 6 main tasks. The first dealt with lamination with poly-vinyl butyral (PVB) interlayers, which prior work had shown difficulties in achieving good quality laminates, working with Pilkington North

  12. Infrared photodissociation spectroscopy of mass-selected silver and gold nitrosyl cation complexes.

    Science.gov (United States)

    Li, Yuzhen; Wang, Lichen; Qu, Hui; Wang, Guanjun; Zhou, Mingfei

    2015-04-16

    The [M(NO)n](+) cation complexes (M = Au and Ag) are studied for exploring the coordination and bonding between nitric oxide and noble metal cations. These species are produced in a laser vaporization supersonic ion source and probed by infrared photodissociation spectroscopy in the NO stretching frequency region using a collinear tandem time-of-flight mass spectrometer. The geometric and electronic structures of these complexes are determined by comparison of the distinctive experimental spectra with simulated spectra derived from density functional theory calculations. All of these noble metal nitrosyl cation complexes are characterized to have bent NO ligands serving as one-electron donors. The spectrum of [Au(NO)2Ar](+) is consistent with 2-fold coordination with a near linear N-Au-N arrangement for this ion. The [Au(NO)n](+) (n = 3-4) cations are determined to be a mixture of 2-fold coordinated form and 3- or 4-fold coordinated form. In contrast, the spectra of [Ag(NO)n](+) (n = 3-6) provide evidence for the completion of the first coordination shell at n = 5. The high [Au(NO)n](+) and [Ag(NO)n](+) (n ≥ 3 for Au, n ≥ 4 for Ag) complexes each involve one or more (NO)2 dimer ligands, as observed in the copper nitrosyl cation complexes, indicating that ligand-ligand coupling plays an important role in the structure and bonding of noble metal nitrosyl cation complexes. PMID:25811327

  13. Co Oxidation Properties Of Selective Dissoluted Metallic Glass Composites

    OpenAIRE

    Kim S.-Y.; Lee M.-H.; Kim T.-S.; Kim B.-S.

    2015-01-01

    Porous metallic materials have been widely used in many fields including aerospace, atomic energy, electro chemistry and environmental protection. Their unique structures make them very useful as lightweight structural materials, fluid filters, porous electrodes and catalyst supports. In this study, we fabricated Ni-based porous metallic glasses having uniformly dispersed micro meter pores by the sequential processes of ball-milling and chemical dissolution method. We investigated the applica...

  14. Glasses

    DEFF Research Database (Denmark)

    Dyre, Jeppe

    2004-01-01

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

  15. Synthesis of calix(aza)crown and its oligomeric analogue for the extraction of selected metal cations and dichromate anions

    Energy Technology Data Exchange (ETDEWEB)

    Akkus, Guelderen Uysal [Department of Chemistry, Afyon Kocatepe University, Afyonkarahisar (Turkey); Memon, Shahabuddin [National Center of Excellence in Analytical Chemistry, University of Sindh, Jamshoro (Pakistan); Sezgin, Mehmet; Yilmaz, Mustafa [Department of Chemistry, Selcuk University, Konya (Turkey)

    2009-02-15

    The present study reports the synthesis of a novel ionophore, calix[4]azacrown (5) bearing two amino groups at the lower rim along with its oligomeric analogue (6). The liquid-liquid extraction properties of these compounds towards selected metal cations and dichromate anions have been evaluated. It is observed that (5) and (6) are good extractants for the selected metal cations. However, in the case of dichromate anion, only species (5) shows remarkable extraction properties at low pH, whereas species (6) shows poor extraction behavior. The results have importance especially in wastewater treatment to obtain environmentally safe industrial effluent and they should also assist supramolecular chemists in designing and synthesizing more sophisticated host molecules for the removal of toxic pollutants. (Abstract Copyright [2009], Wiley Periodicals, Inc.)

  16. Solvent-Free Selective Oxidation of Toluene with O2 Catalyzed by Metal Cation Modified LDHs and Mixed Oxides

    Directory of Open Access Journals (Sweden)

    Xiaoli Wang

    2016-01-01

    Full Text Available A series of metal cation modified layered-double hydroxides (LDHs and mixed oxides were prepared and used to be the selective oxidation of toluene with O2. The results revealed that the modified LDHs exhibited much higher catalytic performance than their parent LDH and the modified mixed oxides. Moreover, the metal cations were also found to play important roles in the catalytic performance and stabilities of modified catalysts. Under the optimal reaction conditions, the highest toluene conversion reached 8.7% with 97.5% of the selectivity to benzyldehyde; moreover, the catalytic performance remained after nine catalytic runs. In addition, the reaction probably involved a free-radical mechanism.

  17. A highly calcium-selective cation current activated by intracellular calcium release in MDCK cells.

    Science.gov (United States)

    Delles, C; Haller, T; Dietl, P

    1995-08-01

    methods, stimulates La(3+)-inhibitable Ca2+ entry in MDCK cells. Ca2+ entry is at least, in part, mediated by a cation current, which is highly, but not exclusively, selective for Ca2+ over Na+ and insensitive to SK&F 96365. PMID:7473219

  18. Structure and properties of selected Fe-based metallic glasses

    Directory of Open Access Journals (Sweden)

    R. Nowosielski

    2009-12-01

    Full Text Available Purpose: The paper presents a structure characterization, thermal and soft magnetic properties of Fe-based bulk amorphous materials in as-cast state and after crystallization process.Design/methodology/approach: The studies were performed on Fe72B20Si4Nb4 metallic glass in form of ribbons and rods. The amorphous structure of tested samples was examined by X-ray diffraction (XRD, transmission electron microscopy (TEM and scanning electron microscopy (SEM methods. The thermal properties of the glassy samples were measured using differential thermal analysis (DTA and differential scanning calorimetry (DSC. The soft magnetic properties examination of tested material contained magnetic permeability and magnetic after-effects measurements.Findings: The X-ray diffraction and transmission electron microscopy investigations revealed that the studied as-cast materials were amorphous. Broad diffraction halo could be seen for all tested samples, indicating the formation of a glassy phase with the diameters up to 2 mm. The fracture surface of rod samples appears to consist of two different zones, which probably inform about different amorphous structures of studied glassy materials. A two stage crystallization process was observed for studied alloy. The first stage of crystallization corresponding to the partial crystallization of α-Fe phase was followed by the formation of iron borides. It has shown that appropriate increasing of annealing temperature, significantly improved soft magnetic properties of examined alloy.Practical implications: The studied Fe-based metallic glass has good glass-forming ability and thermal stability for casting in form of ribbons and rods. The soft magnetic properties of studied alloy could be improved by applying the appropriate conditions of heat treatment (crystallization process.Originality/value: The applied investigation methods are suitable to determine the changes of structure in function of sample thickness and the

  19. Incorporating polyoxometalates into a porous MOF greatly improves its selective adsorption of cationic dyes.

    Science.gov (United States)

    Yan, Ai-Xue; Yao, Shuang; Li, Yang-Guang; Zhang, Zhi-Ming; Lu, Ying; Chen, Wei-Lin; Wang, En-Bo

    2014-06-01

    Various polyoxometalates (POMs) were successfully immobilized to the mesoporous coordination polymer MIL-101 resulting in a series of POM-MOF composite materials POM@MIL-101 (POM = K4PW11VO40, H3PW12O40, K4SiW12O40). These materials were synthesized by a simple one-pot reaction of Keggin POMs, tetramethylammonium hydroxide (TMAH), terephthalic acid (H2bdc), and Cr(3+) ions. XRD, FTIR, thermogravimetric analyses (TG), inductively coupled plasma (ICP) spectrometry, and energy-dispersive X-ray spectroscopy (EDX) collectively confirmed the successful combination of POMs and the porous framework. Further, these composites POM@MIL-101 with different loading of POMs were achieved by variation of the POM dosage. Notably, the uptake capacity of MIL-101 towards organic pollutants in aqueous solution was significantly improved by immobilization of hydrophilic POMs into cages of MIL-101. An uptake capacity of 371 mg g(-1), comparable to that of the graphene oxide sponges, and much higher than that of the commercial activated carbon, was achieved at room temperature in 5 min when dipping 20 mg PW11V@MIL-101 in the methylene blue (MB) solution (100 mL of 100 mg L(-1) MB solution). Further study revealed that the POM@MIL-101 composite materials not only exhibited a fast adsorption rate towards dye molecules, but also possessed of selective adsorption ability of the cationic dyes in wastewater. For example, the adsorption efficiency of PW11V@MIL-101 (10 mg) towards MB (100 mL of 10 mg L(-1)) could reach 98 % in the initial 5 min, and it could capture MB dye molecules from the binary mixture of the MB and MO with similar size. Also, the POM@MIL-101 materials could be readily recycled and reused, and no POM leached in the dye adsorption process. PMID:24737342

  20. Synthesis and cationic selectivity studies of novel calix[4]arene derivatives containing heteroatom at the lower rim

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    A series of calixarene derivatives 2-5 containing heteroatom at the lower rim have been synthesized. 1H NMR studies and crystallographic structures demonstrated that the calix[4]arene derivatives adopted cone conformations. Their cationic binding abilities and selectivities towards heavy and transition metal ions have been evaluated by solvent extraction of aqueous metal picrates. The obtained results indicated that the introduction of nitrogen, sulfur, and/or phosphor atoms to the calix[4]arene framework could effectively enhance their binding ability and selectivity for heavy and transition metal ions, such as Pb2+ or Ag+.

  1. Co Oxidation Properties Of Selective Dissoluted Metallic Glass Composites

    Directory of Open Access Journals (Sweden)

    Kim S.-Y.

    2015-06-01

    Full Text Available Porous metallic materials have been widely used in many fields including aerospace, atomic energy, electro chemistry and environmental protection. Their unique structures make them very useful as lightweight structural materials, fluid filters, porous electrodes and catalyst supports. In this study, we fabricated Ni-based porous metallic glasses having uniformly dispersed micro meter pores by the sequential processes of ball-milling and chemical dissolution method. We investigated the application of our porous metal supported for Pt catalyst. The oxidation test was performed in an atmosphere of 1% CO and 3% O2. Microstructure observation was performed by using a scanning electron microscope. Oxidation properties and BET (Brunauer, Emmett, and Teller were analyzed to understand porous structure developments. The results indicated that CO Oxidation reaction was dependent on the specific surface area.

  2. Enhanced fluorescence of selected cationic dyes adsorbed on reduced-charge montmorillonite

    Czech Academy of Sciences Publication Activity Database

    Pustková, P.; Klika, Z.; Preclíková, J.; Matys Grygar, Tomáš

    2011-01-01

    Roč. 46, č. 1 (2011), s. 93-103. ISSN 0009-8558 Institutional research plan: CEZ:AV0Z40320502 Keywords : cationic dye * crystal violet * Nile blue * rhodamine B * reduced-charge montmorillonite * visible spectrophotometry * fluorescence Subject RIV: DD - Geochemistry Impact factor: 1.053, year: 2011

  3. Characterization of selective binding of alkali cations with carboxylate by x-ray absorption spectroscopy of liquid microjets

    Energy Technology Data Exchange (ETDEWEB)

    Saykally, Richard J; Uejio, Janel S.; Schwartz, Craig P.; Duffin, Andrew M.; Drisdell, Walter S.; Cohen, Ronald C.; Saykally, Richard J.

    2008-01-08

    We describe an approach for characterizing selective binding between oppositely charged ionic functional groups under biologically relevant conditions. Relative shifts in K-shell x-ray absorption spectra of aqueous cations and carboxylate anions indicate the corresponding binding strengths via perturbations of carbonyl antibonding orbitals. XAS spectra measured for aqueous formate and acetate solutions containing lithium, sodium, and potassium cations reveal monotonically stronger binding of the lighter metals, supporting recent results from simulations and other experiments. The carbon K-edge spectra of the acetate carbonyl feature centered near 290 eV clearly indicate a preferential interaction of sodium versus potassium, which was less apparent with formate. These results are in accord with the Law of Matching Water Affinities, relating relative hydration strengths of ions to their respective tendencies to form contact ion pairs. Density functional theory calculations of K-shell spectra support the experimental findings.

  4. Space-selective growth of frequency-conversion crystals in glasses with ultrashort infrared laser pulses.

    Science.gov (United States)

    Miura, K; Qiu, J; Mitsuyu, T; Hirao, K

    2000-03-15

    We report on space-selective growth of a second-harmonic-generation beta-BaB(2)O(4) (BBO) crystal inside a BaO-Al(2)O(3)-B(2)O(3) glass sample at the focal point of an 800-nm femtosecond laser beam. A spherical heated region was formed during the focused laser irradiation through observation with an optical microscope. We moved the heated region by changing the position of the focal point of the laser beam relative to the glass sample. We grew BBO crystal continuously in the glass sample by adjusting the moving speed of the heated zone. Our results demonstrate that functional crystals can be formed three dimensionally in glasses by use of a nonresonant ultrashort pulsed laser. PMID:18059895

  5. Titanium (III) cation selective electrode based on synthesized tris(2pyridyl) methylamine ionophore and its application in water samples

    Science.gov (United States)

    Rezayi, Majid; Karazhian, Reza; Abdollahi, Yadollah; Narimani, Leila; Sany, Seyedeh Belin Tavakoly; Ahmadzadeh, Saeid; Alias, Yatimah

    2014-04-01

    The introduction of low detection limit ion selective electrodes (ISEs) may well pave the way for the determination of trace targets of cationic compounds. This research focuses on the detection of titanium (III) cation using a new PVC-membrane sensor based on synthesized tris(2pyridyl) methylamine (tpm) ionophore. The application and validation of the proposed sensor was done using potentiometric titration, inductively coupled plasma atomic emission spectrometry (ICP-AES), and atomic absorption spectrometry (AAS). The membrane sensor exhibited a Nernstian response to the titanium (III) cation over a concentration range of 1.0 × 10-6-1.0 × 10-2 M and pH range from 1-2.5. The Nernstian slope, the lower of detection (LOD), and the response time (t95%) of the proposed sensor were 29.17 +/- 0.24 mV/dec, 7.9 × 10-7 M, and 20 s, respectively. The direct determination of 4-39 μg/ml of titanium (III) standard solution showed an average recovery of 94.60 and a mean relative standard deviation of 1.8 at 100.0 μg/ml. Finally, the utilization of the electrodes as end-point indicators for potentiometric titration with EDTA solutions for titanium (III) sensor was successfully carried out.

  6. Site-selection spectroscopy of Eu/sup 3+/ ions in glass hosts

    International Nuclear Information System (INIS)

    Time resolved site-selection spectroscopy techniques using a pulsed tunable dye-laser were used to characterize the optical properties of Eu/sup 3+/ ions at 4.2K in different types of glasses. The results demonstrate the existence of two or three major non-equivalent types of crystal field sites with the presence of energy transfer

  7. Indirect selective laser sintering of apatite-wollostonite glass-ceramic.

    Science.gov (United States)

    Xiao, K; Dalgarno, K W; Wood, D J; Goodridge, R D; Ohtsuki, C

    2008-10-01

    This paper develops an indirect selective laser sintering (SLS) processing route for apatite-wollastonite (A-W) glass-ceramic, and shows that the processing route, which can create porous three-dimensional products suitable for bone implants or scaffolds, does not affect the excellent mechanical and biological properties of the glass-ceramic. 'Green parts' with fine integrity and well-defined shape have been produced from glass particles of single-size range or mixed-size ranges with acrylic binder in various ratios by weight. A subsequent heat treatment process has been developed to optimize the crystallization process, and an infiltration process has been explored to enhance mechanical strength. Three-point bending test results show flexural strengths of up to 102 MPa, dependent on porosity, and simulated body fluid (SBF) tests show that the laser sintered porous A-W has comparable biological properties to that of conventionally produced A-W. PMID:19024158

  8. Ionic Liquid Synergistic Cation-Exchange System for the Selective Extraction of Lanthanum(III) Using 2-Thenoyltrifluoroacetone and 18-Crown-6

    OpenAIRE

    Hirayama, Naoki; Okamura, Hiroyuki; Kidani, Keiji; Imura, Hisanori

    2008-01-01

    A novel synergistic extraction system was investigated for the possible selective separation of light lanthanoids using an ionic liquid, 1-butyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide, as an extraction solvent and 2-thenoyltrifluoroacetone and 18-crown-6 as extractants. Trivalent lanthanum was efficiently extracted as a cationic ternary complex by the cation-exchange process, whereas europium and lutetium showed relatively low extractability without forming respective ternary ...

  9. Selective adsorption of cationic dyes from aqueous solution by polyoxometalate-based metal-organic framework composite

    Science.gov (United States)

    Liu, Xiaoxia; Gong, Wenpeng; Luo, Jing; Zou, Chentao; Yang, Yun; Yang, Shuijin

    2016-01-01

    A novel environmental friendly adsorbent H6P2W18O62/MOF-5 was synthesized by a simple one-step reaction under solvothermal conditions and characterized by XRD, FTIR, thermogravimetric analyses (TGA) and N2 adsorption-desorption isotherms. The removal rate of H6P2W18O62/MOF-5 was quite greater (85%) than that of MOF-5 (almost zero), showing that the adsorption performance of porous MOF-5 can be improved through the modification of H6P2W18O62. Further study revealed that H6P2W18O62/MOF-5 exhibited a fast adsorption rate and selective adsorption ability towards the cationic dyes in aqueous solution. The removal rate was up to 97% for cationic dyes methylene blue (MB) and 68% for rhodamine B(Rhb) within 10 min. However, anionicdye methyl orange(MO) can only reach to 10%. The influences including initial concentration, contact time, initial solution pH and temperature of MB adsorption onto H6P2W18O62/MOF-5 were investigated in detail. The kinetic study indicated that the adsorption of MB onto H6P2W18O62/MOF-5 followed the pseudo second-order model well. The isotherm obtained from experimental data fitted the Langmuir model, yielding maximum adsorption capacity of 51.81 mg/g. The thermodynamic parameters analysis illustrated that the MB adsorption onto H6P2W18O62 immobilized MOF-5 was spontaneous and endothermic process. Besides, these results implied that designing a novel material polyoxometalate-based metal-organic frameworks is great potential for removing cationic organic pollutants and even extended to improve other specific application.

  10. Selective removal of toxic anionic dyes using a novel nanocomposite derived from cationically modified guar gum and silica nanoparticles.

    Science.gov (United States)

    Patra, Abhay Shankar; Ghorai, Soumitra; Ghosh, Shankhamala; Mandal, Barun; Pal, Sagar

    2016-01-15

    A novel nanocomposite derived from cationically modified guar gum and in-situ incorporated SiO2 NP (cat-GG/SiO2) has been developed. The cat-GG has been synthesised by grafting poly(2-(diethylamino)ethyl methacrylate) on GG backbone. Various analyses endorse the suitability of cat-GG as well-organized template for the development of homogeneous SiO2 NPs. Dye adsorption studies predict that cat-GG/SiO2 efficiently and selectively adsorb anionic dyes (reactive blue-RB and Congo red-CR) from mixture of dye solutions. This is because of high surface area, multifunctional chelating H-bonding interactions and electrostatic interactions of cationic adsorbent with anionic dyes. Dyes adsorbed on the composite surface are desorbed reversibly using pH 10 stripping solution. Besides, cat-GG/SiO2 has been recycled efficiently with no prominent loss of dye uptake capacity, even after 4 adsorption-desorption cycles. PMID:26348145

  11. Maitotoxin-induced cell death cascade in bovine aortic endothelial cells: divalent cation specificity and selectivity.

    Science.gov (United States)

    Wisnoskey, Brian J; Estacion, Mark; Schilling, William P

    2004-08-01

    The maitotoxin (MTX)-induced cell death cascade in bovine aortic endothelial cells (BAECs), a model for Ca(2+) overload-induced toxicity, reflects three sequential changes in plasmalemmal permeability. MTX initially activates Ca(2+)-permeable, nonselective cation channels (CaNSC) and causes a massive increase in cytosolic free Ca(2+) concentration ([Ca(2+)](i)). This is followed by the opening of large endogenous cytolytic/oncotic pores (COP) that allow molecules ionomycin and were significantly delayed in BAPTA-loaded cells. Experiments at the single-cell level revealed that Ba(2+) not only delayed the time to cell lysis but also caused desynchronization of the lytic phase. Last, membrane blebs, which were numerous and spherical in Ca(2+)-containing solutions, were poorly defined and greatly reduced in number in the presence of Ba(2+). Taken together, these results suggest that intracellular high-affinity Ca(2+)-binding proteins are involved in the MTX-induced changes in plasmalemmal permeability that are responsible for cell demise. PMID:15044153

  12. Influences of Hard Donor on Cation Selectivities Closing to Soft Selenium Donor in Tweezer-like Calix[4]arene Receptors

    Institute of Scientific and Technical Information of China (English)

    LIU,Chang-Ying(刘长鹰); ZHANG,Zheng-Zhi(张正之); QIN,Da-Bin(秦大斌); LENG,Xue-Bing(冷雪冰); CHEN,Lang-Xing(陈朗星); ZENG,Xian-Shun(曾宪顺); XU,Feng-Bo(徐凤波); LI,Qing-Shan(李庆山); HE,Xi-Wen(何锡文); ZHANG,Wen-Qin(张文勤)

    2004-01-01

    Three novel 25,27-dihydroxy-26,28-bis(3-benzylselenopropoxy)-5,11,17,23-tetra-tert-butylcalix[4]-arene (2),25,27-dihydroxy-26,28-bis[3-(2-hydroxyethylseleno)propoxy]-5,11,17,23-tetra-tert-butyl-calix[4]arene (3) and 25,27-dihydroxy-26,28-bis(3-propylselenopropoxy)-5,11,17,23-tetra-tert-butyl-calix[4]arene (4) were synthesized for the comparison of their ion-selectivity in ion-selective electrodes (ISE). X-ray structure of the CH/π complex of 4·CH2Cl2 was elucidated. ISEs based on 2-4 as neutral ionophores were prepared, and their selectivity coefficients for Ag+ (log Kpot Ag,M) were investigated against some main group metal ions and transition metal ones using the fixed interference method (FIM). These ISEs showed excellent Ag+ selectivity over most of the interfering cations examined. It is evident that the stronger Hg2+ interference may not be produced while hard donors (hydroxy) are close to the soft selenium donors.

  13. A pass too far: dissociation of internal energy selected paracyclophane cations, theory and experiment.

    Science.gov (United States)

    Hemberger, Patrick; Bodi, Andras; Schon, Christof; Steinbauer, Michael; Fischer, Kathrin H; Kaiser, Conrad; Fischer, Ingo

    2012-09-14

    The vacuum ultraviolet (VUV) photoionization and dissociative photoionization of three hydroxy-substituted [2.2]paracyclophane derivatives were studied yielding adiabatic ionization energies and dissociative photoionization energies (appearance energies). The simplest dissociation pathway is the breaking of both CH(2)-CH(2) bridge units and fragmenting the molecular ion in half to yield xylylene neutral and cationic fragments. The experimental data show that this process is outcompeted by a faster, higher energy channel, possibly yielding cyclooctatetraene derivatives. The role of the reaction coordinate, the effect of large amplitude motions on the density of states function at low and high energies and the temperature dependent 'population gap' in the internal energy distribution in large molecules are discussed in the context of applying statistical models to the dissociation. Computational approaches to the binding energy of paracyclophanes are marred with pitfalls. Noncovalent interactions play a major role in keeping paracyclophanes bound by some 200 kJ mol(-1) with respect to the two xylylene motifs, and the covalent CH(2)-CH(2) bonds are mostly counteracted by the geometric strain. The stabilizing effects are twofold: first, paracyclophanes are aromatic compounds, whereas xylylenes are not. Thus, the aromaticity of the molecule is induced by dimerization. Second, dispersive π-π interactions also stabilize the molecule. We evaluated 23 different computational chemistry approaches, and found that very few of the favorably scaling ones give an adequate description of this system. Among the DFT functionals tested, only PBE-D3 and perhaps M06-2X yielded consistently accurate results, comparable with MP3 and CCSD, or the G4 and CBS-QB3 composite methods. MP2 results in general suffer from significant overbonding. PMID:22847148

  14. Coverage Dependent Charge Reduction of Cationic Gold Clusters on Surfaces Prepared Using Soft Landing of Mass-selected Ions

    Energy Technology Data Exchange (ETDEWEB)

    Johnson, Grant E.; Priest, Thomas A.; Laskin, Julia

    2012-11-29

    The ionic charge state of monodisperse cationic gold clusters on surfaces may be controlled by selecting the coverage of mass-selected ions soft landed onto a substrate. Polydisperse diphosphine-capped gold clusters were synthesized in solution by reduction of chloro(triphenylphosphine)gold(I) with borane tert-butylamine in the presence of 1,3-bis(diphenylphosphino)propane. The polydisperse gold clusters were introduced into the gas phase by electrospray ionization and mass selection was employed to select a multiply charged cationic cluster species (Au11L53+, m/z = 1409, L = 1,3-bis(diphenylphosphino)propane) which was delivered to the surfaces of four different self-assembled monolayers on gold (SAMs) at coverages of 1011 and 1012 clusters/mm2. Employing the spatial profiling capabilities of in-situ time-of-flight secondary ion mass spectrometry (TOF-SIMS) it is shown that, in addition to the chemical functionality of the monolayer (as demonstrated previously: ACS Nano, 2012, 6, 573) the coverage of cationic gold clusters on the surface may be used to control the distribution of ionic charge states of the soft-landed multiply charged clusters. In the case of a 1H,1H,2H,2H-perfluorodecanethiol SAM (FSAM) almost complete retention of charge by the deposited Au11L53+ clusters was observed at a lower coverage of 1011 clusters/mm2. In contrast, at a higher coverage of 1012 clusters/mm2, pronounced reduction of charge to Au11L52+ and Au11L5+ was observed on the FSAM. When soft landed onto 16- and 11-mercaptohexadecanoic acid surfaces on gold (16,11-COOH-SAMs), the mass-selected Au11L53+ clusters exhibited partial reduction of charge to Au11L52+ at lower coverage and additional reduction of charge to both Au11L52+ and Au11L5+ at higher coverage. The reduction of charge was found to be more pronounced on the surface of the shorter (thinner) C11 than the longer (thicker) C16-COOH-SAM. On the surface of the 1-dodecanethiol (HSAM) monolayer, the most abundant charge state

  15. Spectrally-selective all-inorganic scattering luminophores for solar energy-harvesting clear glass windows.

    Science.gov (United States)

    Alghamedi, Ramzy; Vasiliev, Mikhail; Nur-E-Alam, Mohammad; Alameh, Kamal

    2014-01-01

    All-inorganic visibly-transparent energy-harvesting clear laminated glass windows are the most practical solution to boosting building-integrated photovoltaics (BIPV) energy outputs significantly while reducing cooling- and heating-related energy consumption in buildings. By incorporating luminophore materials into lamination interlayers and using spectrally-selective thin-film coatings in conjunction with CuInSe2 solar cells, most of the visible solar radiation can be transmitted through the glass window with minimum attenuation while ultraviolet (UV) radiation is down-converted and routed together with a significant part of infrared radiation to the edges for collection by solar cells. Experimental results demonstrate a 10 cm × 10 cm vertically-placed energy-harvesting clear glass panel of transparency exceeding 60%, invisible solar energy attenuation greater than 90% and electrical power output near 30 Wp/m(2) mainly generated by infrared (IR) and UV radiations. These results open the way for the realization of large-area visibly-transparent energy-harvesting clear glass windows for BIPV systems. PMID:25321890

  16. Modeling of cesium sorption on biotite using cation exchange selectivity coefficients

    Energy Technology Data Exchange (ETDEWEB)

    Kylloenen, Jarkko; Hakanen, Martti; Harjula, Risto; Lehto, Jukka [Helsinki Univ. (Finland). Lab. of Radiochemistry; Lindberg, Antero [Geological Survey of Finland, Espoo (Finland); Vehkamaeki, Marko [Helsinki Univ. (Finland). Lab. of Inorganic Chemistry

    2014-07-01

    For the modeling of cesium sorption on biotite, samples of natural biotite separated from gneissic rocks were converted into monoionic potassium, sodium, and calcium forms, and sorption isotherms for Cs/K, Cs/Na and Cs/Ca exchange were determined at pH 6 and 8 in 10{sup -4}-10{sup -8} M Cs solutions. Selectivity coefficients for Cs/K, Cs/Na, and Cs/Ca ion exchange reactions were calculated from the isotherm data, using the Gaines-Thomas convention. At Cs loadings below 1% of the total ion exchange capacity, the overall selectivity coefficient for Cs/Ca exchange was approximately five and seven orders of magnitude higher than those for Cs/Na and Cs/K exchange, respectively. Based on the selectivity coefficients, the ion exchange isotherms were modeled with the U.S. Geological Survey PhreeqC program, assuming three different types of ion exchange site: sites on the basal planes on biotite crystal surfaces with 95% site abundance, probable interlayer sites on crystal edges [frayed edge sites (FESs)] (0.02%) and third-type sites (5%), the physical background of which is unclear. Of these three types, the FES sites were superior in Cs selectivity, while the planar sites exhibited the lowest selectivity, and the third-type sites had selectivity between these two. The functionality of the model was successfully verified by modeling the Cs sorption isotherms on crushed mica gneiss rock in saline groundwater. Determination of the exchangeable ions K, Na, Ca, and Cs on the basal plane and edge surfaces by scanning electron microscopy-energy-dispersive x-ray spectroscopy (SEM-EDX) supports the results of modeling: edge sites highly prefer Cs ions and also Ca and Na ions but not K ions.

  17. Accuracy of a selection criterion for glass forming ability in the Ni–Nb–Zr system

    International Nuclear Information System (INIS)

    Highlights: • We applied a selection in the Ni–Nb–Zr system to find alloys with high GFA. • We used the thermal parameter γm to evaluate the GFA of alloys. • The correlation between the γm parameter and Rc in the studied system is poor. • The effect of oxygen impurity reduced dramatically the GFA of alloys. • Unknown intermetallic compounds reduced the accuracy of the criterion. - Abstract: Several theories have been developed and applied in metallic systems in order to find the best stoichiometries with high glass forming ability; however there is no universal theory to predict the glass forming ability in metallic systems. Recently a selection criterion was applied in the Zr–Ni–Cu system and it was found some correlation between experimental and theoretical data. This criterion correlates critical cooling rate for glass formation with topological instability of stable crystalline structures; average work function difference and average electron density difference among the constituent elements of the alloy. In the present work, this criterion was applied in the Ni–Nb–Zr system. It was investigated the influence of factors not considered in the calculation and on the accuracy of the criterion, such as unknown intermetallic compounds and oxygen contamination. Bulk amorphous specimens were produced by injection casting. The amorphous nature was analyzed by X-ray diffraction and differential scanning calorimetry; oxygen contamination was quantified by the inert gas fusion method

  18. Selective separation of beta-lactoglobulin from sweet whey using CGAs generated from the cationic surfactant CTAB.

    Science.gov (United States)

    Fuda, Elisabeth; Bhatia, Divesh; Pyle, D L; Jauregi, Paula

    2005-06-01

    The selective separation of whey proteins was studied using colloidal gas aphrons generated from the cationic surfactant cetyl trimethyl ammonium bromide (CTAB). From the titration curves obtained by zeta potential measurements of individual whey proteins, it was expected to selectively adsorb the major whey proteins, i.e., bovine serum albumin, alpha-lactalbumin, and beta-lactoglobulin to the aphrons and elute the remaining proteins (lactoferrin and lactoperoxidase) in the liquid phase. A number of process parameters including pH, ionic strength, and mass ratio of surfactant to protein (M(CTAB)/M(TP)) were varied in order to evaluate their effect on protein separation. Under optimum conditions (2 mmol/l CTAB, M(CTAB)/M(TP) = 0.26-0.35, pH 8, and ionic strength = 0.018 mol/l), 80-90% beta-lactoglobulin was removed from the liquid phase as a precipitate, while about 75% lactoferrin and lactoperoxidase, 80% bovine serum albumin, 95% immunoglobulin, and 65% alpha-lactalbumin were recovered in the liquid fraction. Mechanistic studies using zeta potential measurements and fluorescence spectroscopy proved that electrostatic interactions modulate only partially the selectivity of protein separation, as proteins with similar surface charges do not separate to the same extent between the two phases. The selectivity of recovery of beta-lactoglobulin probably occurs in two steps: the first being the selective interaction of the protein with opposite-charged surfactant molecules by means of electrostatic interactions, which leads to denaturation of the protein and subsequent formation and precipitation of the CTAB-beta-lactoglobulin complex. This is followed by the separation of CTAB-beta-lactoglobulin aggregates from the bulk liquid by flotation in the aphron phase. In this way, CGAs act as carriers which facilitate the removal of protein precipitate. PMID:15816026

  19. Spatio-selective surface modification of glass assisted by laser-induced deposition of gold nanoparticles

    International Nuclear Information System (INIS)

    Using pulsed laser irradiation (532 nm), dodecanethiol-capped gold nanoparticles (DT-Au) were deposited on the laser-irradiated region of a hydrophobic glass substrate modified with dimethyloctadecylchlorosilane (DMOS). After removal of deposited DT-Au, the laser-deposited region on the substrate was hydrophilic, as verified by static water contact angles. X-ray photoelectron spectroscopy suggested that the naked glass surface was not exposed at the hydrophilic region. Immersion of the substrate into gold nanorod (NR) solution selectively immobilized NRs on the hydrophilic surface via electrostatic interactions, indicating that the hydrophilic region was an anionic surface. From these results, it is expected that some immobilized DMOS groups on the laser-irradiated region of the substrate were oxidized during DT-Au deposition and fragmentation of the deposited DT-Au

  20. 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.

  1. Understanding selectivity of hard and soft metal cations within biological systems using the subvalence concept. I. Application to blood coagulation: direct cation-protein electronic effects vs. indirect interactions through water networks

    Science.gov (United States)

    de Courcy, B.; Pedersen, L. G.; Parisel, O.; Gresh, N.; Silvi, B.; Pilmé, J.; Piquemal, J.-P.

    2010-01-01

    Following a previous study by de Courcy et al. ((2009) Interdiscip. Sci. Comput. Life Sci. 1, 55-60), we demonstrate in this contribution, using quantum chemistry, that metal cations exhibit a specific topological signature in the electron localization of their density interacting with ligands according to its “soft” or “hard” character. Introducing the concept of metal cation subvalence, we show that a metal cation can split its outer-shell density (the so-called subvalent domains or basins) according to it capability to form a partly covalent bond involving charge transfer. Such behaviour is investigated by means of several quantum chemical interpretative methods encompasing the topological analysis of the Electron Localization Function (ELF) and Bader's Quantum Theory of Atoms in Molecules (QTAIM) and two energy decomposition analyses (EDA), namely the Restricted Variational Space (RVS) and Constrained Space Orbital Variations (CSOV) approaches. Further rationalization is performed by computing ELF and QTAIM local properties such as electrostatic distributed moments and local chemical descriptors such as condensed Fukui Functions and dual descriptors. These reactivity indexes are computed within the ELF topological analysis in addition to QTAIM offering access to non atomic reactivity local index, for example on lone pairs. We apply this “subvalence” concept to study the cation selectivity in enzymes involved in blood coagulation (GLA domains of three coagulation factors). We show that the calcium ions are clearly able to form partially covalent charge transfer networks between the subdomain of the metal ion and the carboxylate oxygen lone pairs whereas magnesium does not have such ability. Our analysis also explains the different role of two groups (high affinity and low affinity cation binding sites) present in GLA domains. If the presence of Ca(II) is mandatory in the central “high affinity” region to conserve a proper folding and a charge

  2. Cation Selectivity by the CorA Mg2+ Channel Requires a Fully Hydrated Cation†

    OpenAIRE

    Moomaw, Andrea S.; Maguire, Michael E.

    2010-01-01

    The CorA Mg2+ channel is the primary uptake system in about half of all bacteria and archaea. However, the basis for its Mg2+ selectivity is unknown. Previous data suggested that CorA binds a fully hydrated Mg2+ ion, unlike other ion channels. The crystal structure of Thermotoga maritima CorA shows a homopentamer with two transmembrane segments per monomer connected by a short periplasmic loop. This highly conserved loop, 281EFMPELKWS289 in Salmonella enterica serovar Typhimurium CorA, is the...

  3. Flow Chronopotentiometry with Ion-Selective Membranes for Cation, Anion, and Polyion Detection.

    Science.gov (United States)

    Ghahraman Afshar, Majid; Crespo, Gastón A; Bakker, Eric

    2016-04-01

    We report here on the development of a chronopotentiometric readout for ion-selective electrodes that allows one to record transition times in continuous flow conditions without the necessity to stop the flow. A sample plug of 150 μL is injected into the carrier solution (0.5 mM NaCl) and subsequently transported to the detection cell (∼20 μL) at moderate flow rates (∼0.5 mL min(-1)), where a short current pulse (5s) is applied between the ionophore-based working electrode and a biocompatible and nonpolarizable Donnan exclusion anion-exchanger membrane reference/counter electrode. Flow conditions bear an influence on the thickness of the aqueous diffusion layer and result in a shift of the chronopotentiometric transition time with respect to stopped flow. Two models based on rotating disk electrodes and flow chronopotentiometry at metal-based electrodes were used to corroborate the data. The method was successfully applied to the determination of calcium, chloride, alkalinity, acidity, and protamine with a range of ion-selective membranes. Because of the limiting exposure time of ca. 20 s of the membranes with the sample, this approach is demonstrated to be useful for the detection of protamine in the therapeutic range of undiluted human blood. PMID:26932542

  4. Selective Interaction of a Cationic Polyfluorene with Model Lipid Membranes: Anionic versus Zwitterionic Lipids

    Directory of Open Access Journals (Sweden)

    Zehra Kahveci

    2014-03-01

    Full Text Available This paper explores the interaction mechanism between the conjugated polyelectrolyte {[9,9-bis(6'-N,N,N-trimethylammoniumhexyl]fluorene-phenylene}bromide (HTMA-PFP and model lipid membranes. The study was carried out using different biophysical techniques, mainly fluorescence spectroscopy and microscopy. Results show that despite the preferential interaction of HTMA-PFP with anionic lipids, HTMA-PFP shows affinity for zwitterionic lipids; although the interaction mechanism is different as well as HTMA-PFP’s final membrane location. Whilst the polyelectrolyte is embedded within the lipid bilayer in the anionic membrane, it remains close to the surface, forming aggregates that are sensitive to the physical state of the lipid bilayer in the zwitterionic system. The different interaction mechanism is reflected in the polyelectrolyte fluorescence spectrum, since the maximum shifts to longer wavelengths in the zwitterionic system. The intrinsic fluorescence of HTMA-PFP was used to visualize the interaction between polymer and vesicles via fluorescence microscopy, thanks to its high quantum yield and photostability. This technique allows the selectivity of the polyelectrolyte and higher affinity for anionic membranes to be observed. The results confirmed the appropriateness of using HTMA-PFP as a membrane fluorescent marker and suggest that, given its different behaviour towards anionic and zwitterionic membranes, HTMA-PFP could be used for selective recognition and imaging of bacteria over mammalian cells.

  5. Nano-baskets of Calix[4]-1,3-crown in Emulsion Membranes for Selective Extraction of Alkali Metal Cations

    Institute of Scientific and Technical Information of China (English)

    Bahram Mokhtari; Kobra Pourabdollah

    2013-01-01

    Nano-assisted inclusion separation of alkali metals from basic solutions was reported by inclu-sion-facilitated emulsion liquid membrane process. The novelty of this study is application of nano-baskets of calixcrown in the selective and efficient separation of alkali metals as both the carrier and the surfactant. For this aim, four derivatives of diacid calix[4]-1,3-crowns-4,5 were synthesized, and their inclusion-extraction parameters were optimized including the calixcrown scaffold (4.4%, by mass) as the carrier/demulsifier, the commercial kero-sene as diluent in membrane, sulphonic acid (0.2 mol·L-1) and ammonium carbonate (0.4 mol·L-1) as the strip and the feed phases, the phase and the treat ratios of 0.8 and 0.3, mixing speed (300 r·min-1), and initial solute concen-tration (100 mg·L-1). The selectivity of membrane over more than ten interfering cations was examined and the re-sults reveled that under the optimized operating condition, the degree of inclusion-extraction of alkali metals was as high as 98%-99%.

  6. Enhancing biocompatibility of some cation selective electrodes using heparin modified bacterial cellulose.

    Science.gov (United States)

    Badr, Ibrahim H A; Abdel-Sattar, R; Keshk, Sherif M A S

    2015-12-10

    Bacterial cellulose (BC) and heparin-modified bacterial cellulose (HBC) were utilized to enhance the biocompatibility of highly thrombogenic PVC-based potassium and calcium membrane electrodes. Three types of membrane electrodes were prepared: (1) conventional PVC electrode (control), (2) PVC-based electrode sandwiched with bacterial cellulose membrane (BC-PVC), and (3) PVC-based electrode sandwiched with heparin-modified bacterial cellulose membrane (HBC-PVC). The potentiometric response characteristics of the modified potassium and calcium membrane electrodes (BC-PVC and HBC-PVC) were compared with those of the control PVC-based potassium and calcium selective electrode, respectively. Response characteristics of the modified membrane electrodes were comparable to the control PVC membrane electrode. The platelet adhesion investigations indicated that (BC) and (HBC) layers are less thrombogenic compared to PVC. Therefore, use of BC or HBC would enable the enhancement of the biocompatibility of PVC-based membrane electrodes for potassium and calcium while practically maintaining the overall electrochemical performance of the PVC sensing film. PMID:26428173

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

    International Nuclear Information System (INIS)

    Selective Internal Radiotherapy is used to treat hepatocellular carcinoma. In this treatment 90Y -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 90Y annihilates the cancer cells. A macroaggregate of albumin containing technetium is previously used to monitor the lung shunt and to prevent the spreading of 90Y during the treatment. In the present work, 165Ho- doped phosphate glass microspheres were developed aiming that application. 165Ho has high cross section for neutron capture (64 bars) and 166Ho 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 (P2O5) tetrahedrons and can be produced by a relatively lower melting temperature of chemical compounds. The 31P 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)

  8. Biophysical studies of the interaction of squalamine and other cationic amphiphilic molecules with bacterial and eukaryotic membranes: importance of the distribution coefficient in membrane selectivity.

    Science.gov (United States)

    Di Pasquale, Eric; Salmi-Smail, Chanaz; Brunel, Jean-Michel; Sanchez, Patrick; Fantini, Jacques; Maresca, Marc

    2010-02-01

    The interaction of squalamine (SQ) with eukaryotic and prokaryotic membranes was studied and compared with the interaction of two other cationic amphipathic antimicrobials (CAAs), i.e. the antibiotic polymyxin B (PMB) and the detergent hexadecyltrimethylammonium bromide (CTAB). Whole cell experiments showed that the three CAA have in common the ability to interact with lipopolysaccharide-containing membranes through a divalent cation sensitive process. Differences were found regarding their kinetics of membrane permeabilisation and their selectivity for bacteria, with a preferential permeabilisation of bacteria by PMB>SQ and no selectivity for CTAB. Experiments with lipid monolayers and bilayers showed that this selectivity did not correlate with a preferential interaction of the CAAs with lipids but rather relies on differences in their ability to penetrate lipid bilayers and to cause electrically active lesions. Incidentally, our results also suggest that the distribution coefficient of CAAs could be used to predict their selectivity for bacteria. PMID:19883637

  9. Actinide cation-cation complexes

    International Nuclear Information System (INIS)

    The +5 oxidation state of U, Np, Pu, and Am is a linear dioxo cation (AnO2+) with a formal charge of +1. These cations form complexes with a variety of other cations, including actinide cations. Other oxidation states of actinides do not form these cation-cation complexes with any cation other than AnO2+; therefore, cation-cation complexes indicate something unique about AnO2+ cations compared to actinide cations in general. The first cation-cation complex, NpO2+·UO22+, was reported by Sullivan, Hindman, and Zielen in 1961. Of the four actinides that form AnO2+ species, the cation-cation complexes of NpO2+ have been studied most extensively while the other actinides have not. The only PuO2+ cation-cation complexes that have been studied are with Fe3+ and Cr3+ and neither one has had its equilibrium constant measured. Actinides have small molar absorptivities and cation-cation complexes have small equilibrium constants; therefore, to overcome these obstacles a sensitive technique is required. Spectroscopic techniques are used most often to study cation-cation complexes. Laser-Induced Photacoustic Spectroscopy equilibrium constants for the complexes NpO2+·UO22+, NpO2+·Th4+, PuO2+·UO22+, and PuO2+·Th4+ at an ionic strength of 6 M using LIPAS are 2.4 ± 0.2, 1.8 ± 0.9, 2.2 ± 1.5, and ∼0.8 M-1

  10. Ionic liquid synergistic cation-exchange system for the selective extraction of lanthanum(III) using 2-thenoyltrifluoroacetone and 18-crown-6.

    Science.gov (United States)

    Hirayama, Naoki; Okamura, Hiroyuki; Kidani, Keiji; Imura, Hisanori

    2008-06-01

    A novel synergistic extraction system was investigated for the possible selective separation of light lanthanoids using an ionic liquid, 1-butyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide, as an extraction solvent and 2-thenoyltrifluoroacetone and 18-crown-6 as extractants. Trivalent lanthanum was efficiently extracted as a cationic ternary complex by the cation-exchange process, whereas europium and lutetium showed relatively low extractability without forming respective ternary complexes. This result is thought to originate in a size-fitting effect of 18-crown-6 to lanthanum and the unique nature of the ionic liquid as a chelate extraction solvent. PMID:18544855

  11. Location and valence state of strontium cations on the framework of a carbon dioxide selective porous silicoaluminophosphate

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Li; Rivera-Ramos, Milton E.; Hernández-Maldonado, Arturo J. (Puerto Rico)

    2014-05-28

    A Sr{sup 2+}-SAPO-34 material that displays superior CO2 adsorption selectivity and capacity was characterized via XPS and UV-vis spectroscopy to elucidate the valence state of strontium cations and framework silicon environment. Most importantly, the location of the strontium has been estimated from a Rietveld refinement analysis of synchrotron diffraction data. The XPS analysis indicated that the apparent valence state of the strontium is less than 2, an indication of its interaction with the large anionic framework. Furthermore, UV-vis tests pointed to changes in the silicon environment, plausibly related to this valence state or framework faulting. For the refinement, the analysis found that strontium occupied two unique sites: a site Sr1 slightly displaced from six-membered rings and a site Sr2 positioned at the top or bottom of the eight-membered rings. The latter position favors the interaction of the alkaline earth metal with CO{sub 2}, probably resulting in an enhanced electric field-quadrupole moment interaction.

  12. Study of the spheroidization process of glass particles for selective internal radiotherapy

    International Nuclear Information System (INIS)

    The selective internal radiotherapy is an alternative method to treat hepatocellular carcinoma. Glass microspheres containing radionuclides are introduced in the liver through the hepatic artery, and they are housed preferentially in the region where the cancer cells are located. The microspheres are trapped in the arterioles which feed the tumors, and the β- particles annihilate the cancer cells. When these particles simultaneously emit γ rays, they can also be used to provide images of the tumor. The glass particles must be spherical to avoid unnecessary bleeding, and the particle size must be restricted to a range which is appropriated to trap them and avoid the migration to other parts of the body. Furthermore, they must have a good chemical durability and be nontoxic. The particle size distribution of microspheres is not easily predicted based on the original irregular particles since the variation of the aspect ratio and the presence of agglomerates can influence the final result. In the present work, the spheroidization process to obtain microspheres for radiotherapy treatment was studied. The glass microspheres were characterized by X-rays diffraction, Energy Dispersive X-rays Fluorescence Spectroscopy, Differential Scanning Calorimetry, Specific Superficial Area and cytotoxicity test. The dissolution rate in distilled water at 90 degree C (DR∼10-8g.cm-2.min-1), density (2.79g.cm-3), viscosity, and size particle distribution were determined. The surface morphological aspect was evaluated by Scanning Electron Microscopy before and after the chemical durability tests in SBF and after the neutron irradiation. It is proposed that the produced material should be sieved to select the most suitable microspheres

  13. Analysis of crystallization process of selected Fe-based bulk metallic glasses

    Directory of Open Access Journals (Sweden)

    P. Sakiewicz

    2012-12-01

    Full Text Available Purpose: The paper mainly aims to present the influence of annealing temperature on structural changes and magnetic properties of selected Fe-based bulk metallic glasses with chemical composition of Fe43Co14Ni14B20Si5Nb4 (at.%.Design/methodology/approach: The investigated samples were cast in form of the rods with diameter of 1.5 mm by the pressure die casting method. The structure changes in function of annealing temperature were examined by X-ray diffraction (XRD and transmission electron microscopy (TEM methods. The crystallization behaviour of the studied alloy was also examined by differential scanning calorimetry (DSC. Magnetic measurements of annealed samples included the initial magnetic permeability and the magnetic permeability relaxation measurements.Findings: The annealing process at temperature range from 373 to 773 K caused a structural relaxation of tested material, which caused the atomic rearrangements and changes of physical properties in relation to as-cast state. The annealing at higher temperatures (823-923 K obviously caused a formation of α-Fe and iron borides crystalline phases. The increasing of annealing temperature significantly improved soft magnetic properties of examined alloy by increase the initial magnetic permeability and decrease the magnetic permeability relaxation.Practical implications: The investigation of the crystallization process of Fe-based metallic glasses is important for understanding the mechanisms of forming controlled microstructures of these materials with specific physical properties.Originality/value: A proper understanding of crystallization process of Fe-based bulk metallic glasses is still novel scientific problem.

  14. Cesium cation templated selective synthesis of a "cone-shaped" sugar macrotricyclic cryptand: A dual anion-cation molecular recognition of potassium tartrate.

    Science.gov (United States)

    Porwanski, S; Moretti, F; Dumarcay-Charbonnier, F; Marsura, A

    2016-05-01

    Cesium templated Staudinger-aza-Wittig tandem reaction (S.A.W.) has been used in the synthesis of a bis-diazacrown-bis-cellobiosyl-tetra-ureido cryptand. A novel macrotricyclic compound having a "cone-shaped" configuration was selectively obtained. Additionally, first results on potential recognition properties of the cryptand are also given. PMID:26826794

  15. Femtosecond laser structuring of silver-containing glass: Silver redistribution, selective etching, and surface topology engineering

    International Nuclear Information System (INIS)

    Femtosecond direct laser writing in silver-containing phosphate glasses allows for the three-dimensional (3D) implementation of complex photonic structures. Sample translation along or perpendicular to the direction of the beam propagation has been performed, which led to the permanent formation of fluorescent structures, either corresponding to a tubular shape or to two parallel planes at the vicinity of the interaction voxel, respectively. These optical features are related to significant modifications of the local material chemistry. Indeed, silver depletion areas with a diameter below 200 nm were evidenced at the center of the photo-produced structures while photo-produced luminescence properties are attributed to the formation of silver clusters around the multiphoton interaction voxel. The laser-triggered oxidation-reduction processes and the associated photo-induced silver redistribution are proposed to be at the origin of the observed original 3D luminescent structures. Thanks to such material structuring, surface engineering has been also demonstrated. Selective surface chemical etching of the glass has been obtained subsequently to laser writing at the location of the photo-produced structures, revealing features with nanometric depth profiles and radial dimensions strongly related to the spatial distributions of the silver clusters

  16. Femtosecond laser structuring of silver-containing glass: Silver redistribution, selective etching, and surface topology engineering

    Energy Technology Data Exchange (ETDEWEB)

    Desmoulin, Jean-Charles; Petit, Yannick; Cardinal, Thierry, E-mail: thierry.cardinal@icmcb.cnrs.fr [CNRS, ICMCB, UPR 9048, F-33600 Pessac, France and Univ. Bordeaux, ICMCB, UPR 9048, F-33600 Pessac (France); Canioni, Lionel [Université Bordeaux, Centre Lasers Intenses et Applications–UMR 5107 CNRS, 351 cours de la Libération, 33405 Talence Cedex (France); Dussauze, Marc [Université de Bordeaux, Institut des Sciences Moléculaires, CNRS UMR 5255, 351 cours de la Libération, 33405 Talence Cedex (France); Lahaye, Michel [Université de Bordeaux, Placamat, avenue Docteur Albert Schweitzer, 33608 Pessac Cedex (France); Gonzalez, Hernando Magallanes; Brasselet, Etienne [Université Bordeaux, Laboratoire Ondes et Matière d' Aquitaine–UMR 5798, CNRS, 351 cours de la Libération, 33405 Talence Cedex (France)

    2015-12-07

    Femtosecond direct laser writing in silver-containing phosphate glasses allows for the three-dimensional (3D) implementation of complex photonic structures. Sample translation along or perpendicular to the direction of the beam propagation has been performed, which led to the permanent formation of fluorescent structures, either corresponding to a tubular shape or to two parallel planes at the vicinity of the interaction voxel, respectively. These optical features are related to significant modifications of the local material chemistry. Indeed, silver depletion areas with a diameter below 200 nm were evidenced at the center of the photo-produced structures while photo-produced luminescence properties are attributed to the formation of silver clusters around the multiphoton interaction voxel. The laser-triggered oxidation-reduction processes and the associated photo-induced silver redistribution are proposed to be at the origin of the observed original 3D luminescent structures. Thanks to such material structuring, surface engineering has been also demonstrated. Selective surface chemical etching of the glass has been obtained subsequently to laser writing at the location of the photo-produced structures, revealing features with nanometric depth profiles and radial dimensions strongly related to the spatial distributions of the silver clusters.

  17. Fabrication of microchannels by space-selective control of phase separation in glass.

    Science.gov (United States)

    Yu, Yongze; Chen, Yeqin; Chen, Jiejie; Lv, Shichao; Feng, Xu; Qi, Yuzhong; Qiu, Jianrong; Zhou, Shifeng

    2016-07-15

    Microchannels have important scientific applications in many fields, because they enable precise control, manipulation, and analysis of fluid on a micrometer scale. Herein, we demonstrate an effective strategy for fabrication of microchannels, based on the space-selective phase separation in glass induced by a femtosecond laser. The proposed method shows its abilities in fabrication of three-dimensional microchannels with ∼5  mm length scale and a uniform cross section. Moreover, we also achieve the modulation of the morphology on the inner surface of microchannels by using objective lenses with various numerical-apertures. The physical mechanism of the phase separation and microstructure evolution is discussed. Our method provides new opportunities to fabricate microchannels with complex structures and multifunctional integration. PMID:27420538

  18. Thermal and magnetic properties of selected Fe-based metallic glasses

    Directory of Open Access Journals (Sweden)

    R. Nowosielski

    2008-03-01

    Full Text Available Purpose: The work presents a thermal stability characterization and soft magnetic properties analysis of selected Fe-based metallic glasses.Design/methodology/approach: The studies were performed on ribbons prepared by the planar flow casting technique, which is a method of continuous casting of the liquid alloy on a surface of turning copper based wheel. The methods of X-ray diffraction were used for the qualitative phase analysis. The thermal properties associated with crystallization temperature of the glassy alloys were measured using the differential thermal analysis. The magnetic properties were determined by the Maxwell-Wien bridge, fluxometer and VSM methods.Findings: The studied Fe72B20Si4B4 and Fe36Co36B19Si5Nb4 metallic glasses in as-cast state were fully amorphous. The Curie temperature (Tc for Fe72B20Si4B4 alloy has a value of 582 K and Fe36Co36B19Si5Nb4 has higher Tc, which has a value of 605 K. The obtained magnetic properties allow to classify the studied amorphous alloys in as-cast state as soft magnetic materials. The coercive field of tested alloys has a value about 8 A/m. The maximum magnetic permeability of Fe72B20Si4B4 alloy (!max = 21500 is much higher than Fe36Co36B19Si5Nb4 metallic glasses (!max = 3200. Similarly, saturation magnetization of Fe72B20Si4B4 alloy (Bs = 1.04 T is higher than Fe36Co36B19Si5Nb4 (Bs = 0.99 T amorphous alloy.Practical implications: The studied glassy alloys are suitable materials for many electrical application in different elements of magnetic circuits and for manufacturing of sensors and precise current transformers.Originality/value: The obtained results confirm the utility of applied investigation methods in the thermal and magnetic properties analysis of examined amorphous alloys.

  19. Application of ABTS radical cation for selective on-line detection of radical scavengers in HPLC eluates

    NARCIS (Netherlands)

    Koleva, [No Value; Niederlander, HAG; van Beek, TA

    2001-01-01

    The radical cation 2,2 ' -azinobis-(3 -ethylbenzothiazoline-6-sulfonate), (ABTS(.+)) was utilized in an on-line HPLC method for the detection of radical scavengers in complex matrixes. The HPLC-separated analytes react postcolumn with the preformed ABTS(.+), and the induced bleaching is detected as

  20. Yttrium-90 Selective Internal Radiation Therapy with Glass Microspheres for Hepatocellular Carcinoma: Current and Updated Literature Review

    Science.gov (United States)

    Alanis, Lourdes; Cho, Sung-Ki; Saab, Sammy

    2016-01-01

    Hepatocellular carcinoma is the most common primary liver cancer and it represents the majority of cancer-related deaths in the world. More than 70% of patients present at an advanced stage, beyond potentially curative options. Ytrrium-90 selective internal radiation therapy (Y90-SIRT) with glass microspheres is rapidly gaining acceptance as a potential therapy for intermediate and advanced stage primary hepatocellular carcinoma and liver metastases. The technique involves delivery of Y90 infused glass microspheres via the hepatic arterial blood flow to the appropriate tumor. The liver tumor receives a highly concentrated radiation dose while sparing the healthy liver parenchyma due to its preferential blood supply from portal venous blood. There are two commercially available devices: TheraSphere® and SIR-Spheres®. Although, Y90-SIRT with glass microspheres improves median survival in patients with intermediate and advanced hepatocellular carcinoma and has the potential to downstage hepatocellular carcinoma so that the selected candidates meet the transplantable criteria, it has not gained widespread acceptance due to the lack of large randomized controlled trials. Currently, there are various clinical trials investigating the use of Y90-SIRT with glass microspheres for treatment of hepatocellular carcinoma and the outcomes of these trials may result in the incorporation of Y90-SIRT with glass microspheres into the treatment guidelines as a standard therapy option for patients with intermediate and advanced stage hepatocellular carcinoma. PMID:27390539

  1. Discovery of a linear relationship between the glass transition temperature of oxide glasses and the quadrupole splitting of the Fe3+ substituted for the individual network-forming cations (NWF)

    International Nuclear Information System (INIS)

    57Fe-Moessbauer and DTA study of several oxide glasses has revealed that there exists a linear relationship between Tg (glass transition temperature) and Δ (quadrupole splitting) of Fe3+, which is substituted for individual NWF (network former), e.g., V5+, Ti4+, Te4+, Al3+, Ga3+ and B(III). The linear relationship named 'Tg-Δ rule' is expressed by Tg=aΔ+b, which indicates that Tg of oxide glasses is closely correlated to the asymmetry or local distortion of NWF-oxygen polyhedra. The 'Tg-Δ rule' also holds for the γ-ray irradiated tellurite glasses and for the glass-ceramics of calcium aluminate. (orig.)

  2. Cation-Exchange Equilibria with Fused Salts

    International Nuclear Information System (INIS)

    Solute distributions of alkali metal, alkaline- earth, transition metal, and actinide ions have been studied in fused salt-cation exchanger systems. The fused salts employed were alkali halides and nitrates. The cation exchangers used were natural zeolites, synthetic zeolites, high-porosity glasses, and molten oxide mixtures. The molten exchangers were composed of Na2O and B2O3 in various proportions. The relative quantities not only determined the exchanger capacity and electrolyte penetration but also produced distribution coefficients for a given solute which varied over several orders of magnitude. Moreover, they produced marked reversals in the selectivity series. Additional studies on the anion distributions, miscibility diagrams, vapour pressures and diffusion rates in these systems have elucidated the mechanisms involved and the relation of selectivity to solute properties, system thermodynamics, exchanger structure and available functional groups. In the region of high Na2O composition, the distribution coefficients for mono-, di- and trivalent cations in NaCl have not only the same order of selectivity found in Dowex 50-HCl systems but also similar values for the distribution coefficients. The results are summarized qualitatively and compared to behaviour in aqueous systems (Table VII). (author)

  3. A cell shrinkage-induced non-selective cation conductance with a novel pharmacology in Ehrlich-Lettre-ascites tumour cells

    DEFF Research Database (Denmark)

    Lawonn, Peter; Hoffmann, Else K; Hougaard, Charlotte;

    2003-01-01

    In whole-cell recordings on Ehrlich-Lettre-ascites tumour (ELA) cells, the shrinkage-induced activation of a cation conductance with a selectivity ratio P(Na):P(Li):P(K):P(choline):P(NMDG) of 1.00:0.97:0.88:0.03:0.01 was observed. In order of potency, this conductance was blocked by Gd(3+)=benzamil......>amiloride>ethyl-isopropyl-amiloride (EIPA). In patch-clamp studies using the cell-attached configuration, a 14 pS channel became detectable that was reversibly activated upon hypertonic cell shrinkage. It is concluded that ELA cells express a shrinkage-induced cation channel that may reflect a molecular link between amiloride...

  4. Synthesis of a Tweezer-like Bis(phenylthiapropoxy)calix[4]arene as a Cation/π Enhanced Sensor for Ion-Selective Electrodes

    Institute of Scientific and Technical Information of China (English)

    SUN,Hao(孙浩); ZHANG,Zheng-Zhi(张正之); ZENG,Xian-Shun(曾宪顺); LU,Jian-Quan(吕监泉); LENG,Xue-Bing(冷雪冰); CHEN Qi-Fa(陈企发); XU,Feng-Bo(徐风波); LI,Qing-Shan(李庆山); HE,Xi-Wen(何锡文); ZHANG,Wen-Qin(张文勤)

    2002-01-01

    Two novel 25,27-dihydroxy-26,28-bis(3-phenylthiapropoxy)-calix[4]arene (3) and 25,27-dihydroxy-26,28-bis(3-phenylthiapropoxy)-5,11, 17, 23-tetra-tert-butylcalix[4] arene (4) were synthesized for the evaluation of their ion-selectivity in ion-selective electrodes (ISEs). ISEs based on 3 and 4 as neutral ionophores were prepared, and their selectivity coefficients for Ag+ (lg Kpot Ag,M) were investigated against other alkali metal,alkaline-earth metal, aluninum, thallium(Ⅰ), lead and some transition metal ions using the separate solution method (SSM). These ISEs showed excellent Ag + selectivity over most of the interfering cations examined, except for Hg2 + and Fe2 + having relative smaller interference (lgKpot Ag,M≤ -2.1).

  5. NEPHELINE FORMATION POTENTIAL IN SLUDGE BATCH 4 AND ITS IMPACT ON DURABILITY: SELECTING GLASSES FOR A PHASE 3 STUDY

    Energy Technology Data Exchange (ETDEWEB)

    Fox, K

    2006-01-27

    Savannah River National Laboratory's frit development effort for SB4 is being driven by the most current CBU option for this sludge, referred to as Case 15C Blend 1. Candidate frits have been identified for this option via a paper study approach developed by Peeler and Edwards with the intent of down-selecting to a set of key frits whose operating windows (i.e., WL intervals that meet PCCS MAR criteria) are robust to and/or selectively optimal for this sludge option. The primary frits that appear attractive on paper (i.e., down-selected via the paper study) are now being incorporated into this experimental study. The potential for the formation of a nepheline primary crystalline phase is an important factor in frit development for SB4, due to the high Al{sub 2}O{sub 3} content of this sludge. Based upon earlier work by Li et al., glasses that do not satisfy the constraint: (SiO{sub 2}/SiO{sub 2} + Na{sub 2}O + Al{sub 2}O{sub 3}) > 0.62 where the oxides are expressed as mass fractions in the glass, will precipitate nepheline as their primary crystalline phase, hindering the durability of the glass. Based on the most recent compositional projection from the CBU for SB4 (Case 15C Blend 1), 16 glasses have been selected to complement the earlier work by continuing the investigation into the ability of the above constraint to predict the occurrence of a nepheline primary crystalline phase for SB4 glasses and into the impact of such phases on the durability of the SB4 glasses. Glasses were selected to cover WLs which tightly bound the nepheline discriminator value of 0.62, with the intent of refining this value to a level of confidence where it can be incorporated into offline administrative controls and/or the PCCS to support SME acceptability decisions. In addition, glass specimens at WLs of 35 and 40% will be prepared and analyzed to contribute needed data to the ComPro{trademark} database in anticipation of a variability study for SB4. The glasses in Table 4

  6. Selective deposition of conductive copper films on glass surfaces using femtosecond laser surface modification and electroless plating

    Science.gov (United States)

    Xu, Jian; Liao, Yang; Zeng, Huidan; Zhou, Zenghui; Sun, Haiyi; Song, Juan; Wang, Xinshun; Cheng, Ya; Xu, Zhizhan; Sugioka, Koji; Midorikawa, Katsumi

    2008-03-01

    In this paper, selective deposition of conductive copper films on glass surfaces is demonstrated with the assistance of femtosecond laser surface modification followed by electroless plating. Irradiation of femtosecond laser makes it possible to selectively deposit copper films in the irradiated area on glass surfaces coated with silver nitrate films. The influence of the laser direct writing parameters and the electroless plating process on the formation of copper films is discussed. Meanwhile, the electric properties of copper films are investigated, which confirms that copper films are conductive. A tentative mechanism of the selective deposition process is also proposed. In addition, the potential application of this technique for integrating electrical and thermal functions into microdevices is discussed.

  7. The non-selective voltage-activated cation channel in the human red blood cell membrane: reconciliation between two conflicting reports and further characterisation

    DEFF Research Database (Denmark)

    Kaestner, Lars; Christophersen, Palle; Bernhardt, Ingolf; Bennekou, P.

    Erythrocyte; Patch-clamp; Non-specific; cation channel; Voltage dependence; Acetylcholin receptor......Erythrocyte; Patch-clamp; Non-specific; cation channel; Voltage dependence; Acetylcholin receptor...

  8. Enhanced Cationic Charge is a Key Factor in Promoting Staphylocidal Activity of α-Melanocyte Stimulating Hormone via Selective Lipid Affinity.

    Science.gov (United States)

    Singh, Jyotsna; Joshi, Seema; Mumtaz, Sana; Maurya, Nancy; Ghosh, Ilora; Khanna, Shivangi; Natarajan, Vivek T; Mukhopadhyay, Kasturi

    2016-01-01

    The steady rise in antimicrobial resistance poses a severe threat to global public health by hindering treatment of an escalating spectrum of infections. We have previously established the potent activity of α-MSH, a 13 residue antimicrobial peptide, against the opportunistic pathogen Staphylococcus aureus. Here, we sought to determine whether an increase in cationic charge in α-MSH could contribute towards improving its staphylocidal potential by increasing its interaction with anionic bacterial membranes. For this we designed novel α-MSH analogues by replacing polar uncharged residues with lysine and alanine. Similar to α-MSH, the designed peptides preserved turn/random coil conformation in artificial bacterial mimic 1,2-dimyristoyl-sn-glycero-3-phosphocholine:1,2-dimyristoyl-sn-glycero-3-phospho-rac-(1-glycerol) (7:3, w/w) vesicles and showed preferential insertion in the hydrophobic core of anionic membranes. Increased cationic charge resulted in considerable augmentation of antibacterial potency against MSSA and MRSA. With ~18-fold better binding than α-MSH to bacterial mimic vesicles, the most charged peptide KKK-MSH showed enhanced membrane permeabilization and depolarization activity against intact S. aureus. Scanning electron microscopy confirmed a membrane disruptive mode of action for KKK-MSH. Overall, increasing the cationic charge improved the staphylocidal activity of α-MSH without compromising its cell selectivity. The present study would help in designing more effective α-MSH-based peptides to combat clinically relevant staphylococcal infections. PMID:27526963

  9. Fabrication of 13-93 bioactive glass scaffolds for bone tissue engineering using indirect selective laser sintering

    Energy Technology Data Exchange (ETDEWEB)

    Kolan, Krishna C R; Leu, Ming C [Department of Mechanical and Aerospace Engineering, Missouri University of Science and Technology, Rolla, MO (United States); Hilmas, Gregory E [Department of Materials Science and Engineering, Missouri University of Science and Technology, Rolla, MO (United States); Brown, Roger F [Department of Biological Sciences, Missouri University of Science and Technology, Rolla, MO (United States); Velez, Mariano, E-mail: kkd7b@mail.mst.edu, E-mail: mleu@mst.edu [Mo-Sci Corporation, Rolla, MO (United States)

    2011-06-15

    Bioactive glasses are promising materials for bone scaffolds due to their ability to assist in tissue regeneration. When implanted in vivo, bioactive glasses can convert into hydroxyapatite, the main mineral constituent of human bone, and form a strong bond with the surrounding tissues, thus providing an advantage over polymer scaffold materials. Bone scaffold fabrication using additive manufacturing techniques can provide control over pore interconnectivity during fabrication of the scaffold, which helps in mimicking human trabecular bone. 13-93 glass, a third-generation bioactive material designed to accelerate the body's natural ability to heal itself, was used in the research described herein to fabricate bone scaffolds using the selective laser sintering (SLS) process. 13-93 glass mixed with stearic acid (as the polymer binder) by ball milling was used as the powder feedstock for the SLS machine. The fabricated green scaffolds underwent binder burnout to remove the stearic acid binder and were then sintered at temperatures between 675 deg. C and 695 deg. C. The sintered scaffolds had pore sizes ranging from 300 to 800 {mu}m with 50% apparent porosity and an average compressive strength of 20.4 MPa, which is excellent for non-load bearing applications and among the highest reported for an interconnected porous scaffold fabricated with bioactive glasses using the SLS process. The MTT labeling experiment and measurements of MTT formazan formation are evidence that the rough surface of SLS scaffolds provides a cell-friendly surface capable of supporting robust cell growth.

  10. Fabrication of 13-93 bioactive glass scaffolds for bone tissue engineering using indirect selective laser sintering

    International Nuclear Information System (INIS)

    Bioactive glasses are promising materials for bone scaffolds due to their ability to assist in tissue regeneration. When implanted in vivo, bioactive glasses can convert into hydroxyapatite, the main mineral constituent of human bone, and form a strong bond with the surrounding tissues, thus providing an advantage over polymer scaffold materials. Bone scaffold fabrication using additive manufacturing techniques can provide control over pore interconnectivity during fabrication of the scaffold, which helps in mimicking human trabecular bone. 13-93 glass, a third-generation bioactive material designed to accelerate the body's natural ability to heal itself, was used in the research described herein to fabricate bone scaffolds using the selective laser sintering (SLS) process. 13-93 glass mixed with stearic acid (as the polymer binder) by ball milling was used as the powder feedstock for the SLS machine. The fabricated green scaffolds underwent binder burnout to remove the stearic acid binder and were then sintered at temperatures between 675 deg. C and 695 deg. C. The sintered scaffolds had pore sizes ranging from 300 to 800 μm with 50% apparent porosity and an average compressive strength of 20.4 MPa, which is excellent for non-load bearing applications and among the highest reported for an interconnected porous scaffold fabricated with bioactive glasses using the SLS process. The MTT labeling experiment and measurements of MTT formazan formation are evidence that the rough surface of SLS scaffolds provides a cell-friendly surface capable of supporting robust cell growth.

  11. Liquidus temperature and chemical durability of selected glasses to immobilize rare earth oxides waste

    Energy Technology Data Exchange (ETDEWEB)

    Mohd Fadzil, Syazwani Binti; Hrma, Pavel R.; Schweiger, Michael J.; Riley, Brian J.

    2015-06-30

    Pyroprocessing is a reprocessing method for managing and reusing used nuclear fuel (UNF) by dissolving it in an electrorefiner with a molten alkali or alkaline earth chloride salt mixture while avoiding wet reprocessing. Pyroprocessing UNF with a LiCl-KCl eutectic salt releases the fission products from the fuel and generates a variety of metallic and salt-based species, including rare earth (RE) chlorides. If the RE-chlorides are converted to oxides, borosilicate glass is a prime candidate for their immobilization because of its durability and ability to dissolve almost any RE waste component into the matrix at high loadings. Crystallization that occurs in waste glasses as the waste loading increases may complicate glass processing and affect the product quality. This work compares three types of borosilicate glasses in terms of liquidus temperature (TL): the International Simple Glass designed by the International Working Group, sodium borosilicate glass developed by Korea Hydro and Nuclear Power, and the lanthanide aluminoborosilicate (LABS) glass established in the United States. The LABS glass allows the highest waste loadings (over 50 mass% RE2O3) while possessing an acceptable chemical durability.

  12. Ordered and disordered models of local structure around Ag cations in silver borate glasses based on x-ray absorptio n near-edge structure spectroscopy

    Czech Academy of Sciences Publication Activity Database

    Šipr, Ondřej; Dalba, G.; Rocca, F.

    2004-01-01

    Roč. 69, - (2004), 134201/1-134201/16. ISSN 0163-1829 R&D Projects: GA ČR GA202/02/0841 Institutional research plan: CEZ:AV0Z1010914 Keywords : disordered systems * structural analysis * XANES * silver * borate glasses Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 3.075, year: 2004

  13. Synthesis and characterization of a novel hybrid nano composite cation exchanger poly-o-toluidine Sn(IV) tungstate: Its analytical applications as ion-selective electrode

    Science.gov (United States)

    Khan, Asif Ali; Shaheen, Shakeeba

    2013-02-01

    A novel organic-inorganic nano composite cation exchanger poly-o-toluidine Sn(IV) tungstate has been synthesized by incorporation of a polymer material into inorganic precipitate. The material is a class of hybrid ion-exchanger with good ion-exchange properties, reproducibility, stability and good selectivity for heavy metals. The physico-chemical properties of this nano composite material were characterized by using XRD, TGA, FTIR, SEM and TEM. The ion-exchange capacity, pH titrations, elution behavior and chemical stability were also carried out to study ion-exchange properties of the material. Distribution studies for various metal ions revealed that the nano composite is highly selective for Cd(II). An ion-selective membrane electrode was fabricated using this material for the determination of Cd(II) ions in solutions. The analytical utility of this electrode was established by employing it as an indicator electrode in electrometric titrations.

  14. Glass fabrication and analysis literature review and method selection for WTP waste feed qualification

    International Nuclear Information System (INIS)

    The waste feed qualification program is being developed to protect the Hanford Tank Waste Treatment and Immobilization Plant (WTP) safety basis, technical basis, and design by assuring waste acceptance requirements are met for each staged waste feed Campaign prior to transfer from the Hanford Tank Farm to the WTP. The three components of waste feed qualification include: Demonstrate compliance with the waste acceptance criteria; Determine waste processability; and, Demonstrate unit operations at laboratory scale. This literature review addresses the final step of unit operations testing of radioactive Tank Farm samples – the glass fabrication unit operation. Based on Savannah River National Laboratory’s review, the following apparatus are needed by the waste feed qualification laboratory: A high speed, low shear remotable mixer such as the LabRAM or similar to mix the feed and ensure homogenous and representative samples can be obtained to support compositional and rheology measurements; A remotable Haake M5/RV30 rotoviscometer or similar to perform rheological measurements of the melter feed streams; A resistance heated remotable laboratory furnace such as a CM Bottom loaded, elevator furnace (Model 1708 BL) or similar to fabricate the glass coupons; and, Platinum or platinum-alloy crucibles (100 or 250 mL with reinforced rims) to fabricate the glass coupons. The following measurements are recommended: Compositional analysis of waste sample to identify types and quantities of glass former materials; Hydrogen generation rate of waste sample before or after addition of glass former materials; Rheology of waste sample prior to addition of glass former materials; Rheology of waste sample after addition of glass former materials; Compositional analysis of waste sample after addition of glass former materials; and, Visual observation of glass coupon. It should be noted that use of cooling curves to evaluate nepheline formation (or any other forms of crystallization

  15. Selective Deposition of SiO2 on Ion Conductive Area of Soda-lime Glass Surface

    Science.gov (United States)

    Sakai, Daisuke; Harada, Kenji; Hara, Yuichiro; Ikeda, Hiroshi; Funatsu, Shiro; Uraji, Keiichiro; Suzuki, Toshio; Yamamoto, Yuichi; Yamamoto, Kiyoshi; Ikutame, Naoki; Kawaguchi, Keiga; Kaiju, Hideo; Nishii, Junji

    2016-06-01

    Selective deposition of SiO2 nanoparticles was demonstrated on a soda-lime glass surface with a periodic sodium deficient pattern formed using the electrical nanoimprint. Positively charged SiO2 particles generated using corona discharge in a cyclic siloxane vapor, were selectively deposited depending on the sodium pattern. For such phenomena to occur, the sodium ion migration to the cathode side was indispensable to the electrical charge compensation on the glass surface. Therefore, the deposition proceeded preferentially outside the alkali-deficient area. Periodic SiO2 structures with 424 nm and 180 nm heights were obtained using one-dimensional (6 μm period) and two-dimensional (500 nm period) imprinted patterns.

  16. Quasicrystal formation, phase selection and crystallization kinetics in Zr-Cu-Ni-Al based metallic glasses

    International Nuclear Information System (INIS)

    Quaternary Zr-Cu-Ni-Al is one of the best glass forming alloys known. In a narrow concentration range icosahedral quasicrystals are formed upon annealing; in Zr69.5Cu12Ni11Al7.5 the metastable primitive icosahedral phase is probably oxygen stabilized. At slightly higher oxygen contents (about 1 at.%) the formation of a metastable fcc ''big-cube'' phase (NiTi2-type) is competing with very high nucleation rates. The aim of this paper is to investigate in detail the formation of quasicrystals as well as microstructures consisting of the ''big-cube'' phase in order to design in particular nanocrystalline structures by controlled crystallization. Nucleation rates were measured by means of crystallization statistics. By modeling the obtained nucleation rates in the framework of diffusion controlled classical nucleation interfacial energies as well as melting temperatures for the metastable phases could be derived. Atomic mobility was estimated from growth data. Using these data TTT-diagrams can be drawn and microstructures (for example nanocrystalline) predicted. The phase selection during the formation of the metastable structures was observed to depend strongly not only on the exchange of the Zr by Hf or Ti, but also on the late transition elements chosen, hydrogen or oxygen contamination as well as on alloying with small amounts of other elements for example Si, Sn, Y or Mo. Regarding the influence of the late transition metals there is some evidence that the quasicrystals are a hybrid of two structural elements, i.e. the tetragonal Zr2Ni(Al2Cu) and the tetragonal Zr2Cu (MoSi2) structure. The mentioned alloying elements as well as oxygen and hydrogen are assumed to influence the arrangement of the structural elements towards one or the other structure. (orig.)

  17. Wavelength-selective bleaching of the optical spectra of trapped electrons in organic glasses. II

    International Nuclear Information System (INIS)

    Further resolution of the inhomogeneous optical spectra of trapped electrons (e-/sub t/) in organic glasses has been obtained from wavelength selective bleaching and thermal decay studies on 3-methylpentane-d14(3MP-d14) and 2-methyltetrahydrofuran (MTHF) following γ irradiation in the temperature region of 20 K, and limits on the degree of resolution achievable have been indicated. Exposure of 3MP-d14 to light of wavelengths >2100 nm (from a tunable laser) reduces the optical densities at the bleaching wavelength and longer to zero, while ''peeling off'' a portion of the O.D. at all shorter wavelengths but leaving the remainder of the spectrum unaffected. The fraction of the integrated optical spectrum, ∫OD d (eV), removed by bleaching at each wavelength tested, and also by thermal decay, is equivalent to the fraction of the total e-/sub t/ spins removed and measured by ESR. 1064 nm light bleaches the spectrum nearly uniformly, confirming that the spectra of all of the e-/sub t/ have blue tails with similar ease of bleaching. Heretofore unobserved low temperature thermal decay of e-/sub t/ occurs at 20 and 40 K (20% of the spin concentration in 30 min, 35% in 3h). The rate of decay of the optical spectrum decreases with decreasing wavelength of observation (2.5, 2.2, 1.8, and 1.5 μ), but at each wavelength is the same at 40 K as at 20 K, consistent

  18. Antimony(v) cations for the selective catalytic transformation of aldehydes into symmetric ethers, α,β-unsaturated aldehydes, and 1,3,5-trioxanes.

    Science.gov (United States)

    Arias Ugarte, Renzo; Devarajan, Deepa; Mushinski, Ryan M; Hudnall, Todd W

    2016-07-01

    1-Diphenylphosphinonaphthyl-8-triphenylstibonium triflate ([][OTf]) was prepared in excellent yield by treating 1-lithio-8-diphenylphosphinonaphthalene with dibromotriphenylstiborane followed by halide abstraction with AgOTf. This antimony(v) cation was found to be stable toward oxygen and water, and exhibited exceptional Lewis acidity. The Lewis acidity of [][OTf] was exploited in the catalytic reductive coupling of a variety of aldehydes into symmetric ethers of type in good to excellent yields under mild conditions using Et3SiH as the reductant. Additionally, [][OTf] was found to selectively catalyze the Aldol condensation reaction to afford α-β unsaturated aldehydes () when aldehydes with 2 α-hydrogen atoms were used. Finally, [][OTf] catalyzed the cyclotrimerization of aliphatic and aromatic aldehydes to afford the industrially-useful 1,3,5 trioxanes () in good yields, and with great selectivity. This phosphine-stibonium motif represents one of the first catalytic systems of its kind that is able to catalyze these reactions with aldehydes in a controlled, efficient manner. The mechanism of these processes has been explored both experimentally and theoretically. In all cases the Lewis acidic nature of the antimony(v) cation was found to promote these reactions. PMID:27326797

  19. Nitrogen-doping effect on glass formation and primary phase selection in Cu-Zr-Al alloys

    International Nuclear Information System (INIS)

    Research highlights: → Optimal nitrogen doping enhances the glass-forming ability of Cu49Zr44Al7 alloy. → Trace N controls the type of primary precipitate phase during solidification. → The study provides new candidates for the alloying of BMGs in improving GFA. → The study provides effective way in designing BMG composites with selective phase. - Abstract: Effects of nitrogen doping on the glass formation and primary precipitate phase in a ternary Cu-Zr-Al alloy were investigated. An optimized doping level of nitrogen (∼1000 appm) can improve the glass-forming ability of Cu49Zr44Al7 alloy. The type of primary phases from ZrCu (B2) to an unknown Zr- and Al-rich crystalline phase with chemical atomic composition of around Cu38Zr49Al13 in the bulk glassy matrix is controllable by the micro-adjustment of N concentration, which can be utilized as an effective way to design BMG-based composites with selective second phase particles.

  20. Cation-Selective and Anion-Controlled Fluorogenic Behaviors of a Benzothiazole-Attached Macrocycle That Correlate with Structural Coordination Modes.

    Science.gov (United States)

    Ju, Huiyeong; Chang, Duk Jin; Kim, Seulgi; Ryu, Hyunsoo; Lee, Eunji; Park, In-Hyeok; Jung, Jong Hwa; Ikeda, Mari; Habata, Yoichi; Lee, Shim Sung

    2016-08-01

    We report how the metal cation and its counteranions cooperate in the complexation-based macrocyclic chemosensor to monitor the target metal ion via the specific coordination modes. The benzothiazolyl group bearing NO2S2-macrocycle L was synthesized, and its mercury(II) selectivity (for perchlorate salt) as a dual-probe channel (UV-vis and fluorescence) chemosensor exhibiting the largest blue shift and the fluorescence turn-off was observed. In the mercury(II) sensing with different anions, except ClO4(-) and NO3(-), no responses for mercury(II) were observed with other anions such as Cl(-), Br(-), I(-), SCN(-), OAc(-), and SO4(2-). A crystallographic approach for the mononuclear mercury(II) perchlorate complex [Hg(L)(ClO4)2]·0.67CH2Cl2 (1) and polymeric mercury(II) iodide complex [Hg(L)I2]n (2) revealed that the observed anion-controlled mercury(II) sensing in the fluorescence mainly stems from the endo- and exocoordination modes, depending on the anion coordinating ability, which induces either the Hg-Ntert bond formation or not. The detailed complexation process with mercury(II) perchlorate associated with the cation sensing was also monitored with the titration methods by UV-vis, fluorescence spectroscopy, and cold-spray ionization mass spectrometry. PMID:27391394

  1. Reversible, Selective Trapping of Perchlorate from Water in Record Capacity by a Cationic Metal-Organic Framework.

    Science.gov (United States)

    Colinas, Ian R; Silva, Rachel C; Oliver, Scott R J

    2016-02-16

    We report the capture of ppm-level aqueous perchlorate in record capacity and kinetics via the complete anion exchange of a cationic metal-organic framework. Ambient conditions were used for both the synthesis of silver 4,4'-bipyridine nitrate (SBN) and the exchange, forming silver 4,4'-bipyridine perchlorate (SBP). The exchange was complete within 90 min, and the capacity was 354 mg/g, representing 99% removal. These values are greater than current anion exchangers such as the resins Amberlite IRA-400 (249 mg/g), Purolite A530E (104 mg/g), and layered double hydroxides (28 mg/g). Moreover, unlike resins and layered double hydroxides, SBN is fully reusable and displays 96% regeneration to SBN in nitrate solution, with new crystal formation allowing the indefinite cycling for perchlorate. We show seven cycles as proof of concept. Perchlorate contamination of water represents a serious health threat because it is a thyroid endocrine disruptor. This noncomplexing anionic pollutant is significantly mobile and environmentally persistent. Removal of other anionic pollutants from water such as chromate, pertechnetate, or arsenate may be possible by this methodology. PMID:26765213

  2. Fine- and hyperfine-structure effects in molecular photoionization: II. Resonance-enhanced multiphoton ionization and hyperfine-selective generation of molecular cations

    CERN Document Server

    Germann, Matthias

    2016-01-01

    Resonance-enhanced multiphoton ionization (REMPI) is a widely used technique for studying molecular photoionization and producing molecular cations for spectroscopy and dynamics studies. Here, we present a model for describing hyperfine-structure effects in the REMPI process and for predicting hyperfine populations in molecular ions produced by this method. This model is a generalization of our model for fine- and hyperfine- structure effects in one-photon ionization of molecules presented in the preceding companion article. This generalization is achieved by covering two main aspects: (1) treatment of the neutral bound-bound transition including hyperfine structure that makes up the first step of the REMPI process and (2) modification of our ionization model to account for anisotropic populations resulting from this first excitation step. Our findings may be used for analyzing results from experiments with molecular ions produced by REMPI and may serve as a theoretical background for hyperfine-selective ioni...

  3. Periodic nanostructuring of Er/Yb-codoped IOG1 phosphate glass by using ultraviolet laser-assisted selective chemical etching

    International Nuclear Information System (INIS)

    The patterning of submicron period (≅500 nm) Bragg reflectors in the Er/Yb-codoped IOG1 Schott, 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 ultraviolet 213 nm, 150 ps Nd:YAG laser radiation and, subsequently, a chemical development in potassium hydroxide (KOH)/ethylenediamine tetra-acetic acid (EDTA) aqueous solution selectively etches the exposed areas. The electronic changes induced by the 213 nm ultraviolet irradiation are examined by employing spectrophotometric measurements, while an estimation of the refractive index changes recorded is provided by applying Kramers-Kronig transformation to the absorption change data. In addition, real time diffraction efficiency measurements were obtained during the formation of the volume damage grating. After the exposure, the growth of the relief grating pattern in time was measured at fixed time intervals and the dependence of the grating depth on the etching time and exposure conditions is presented. The gratings fabricated are examined by atomic and scanning electron microscopies to reveal the relief topology of the structures. Gratings with average depth of 120 nm and excellent surface quality were fabricated by exposing the IOG1 phosphate glass to 36 000 pulses of 208 mJ/cm2 energy density, followed by developing in the KOH/EDTA agent for 6 min

  4. 阳离子对硅酸盐玻璃激光拉曼光谱影响的研究%Influence of Cations on the Laser Raman Spectra of Silicate Glasses

    Institute of Scientific and Technical Information of China (English)

    熊义; 赵虹霞; 干福熹

    2012-01-01

    Na2O(K2O)-CaO(MgO)-SiO2, Na2O(K2O)-A12O3-SiO2, Na2O(K2O)-B2Q3-SiOz, Na2O(K2O)-PbO-SiO2 and PbO-BaO-SiO2 glass systems were investigated using laser Raman spectroscopic technique. The modification of short-range structure of glass caused by network modifier cations will influence Raman signature. Alkali and alkali-earth ions can weaken the bridging oxygen bond, thus lower the frequency of Si-Ob-Si anti-symmetric stretching vibration. When coordinated by oxygen ions, B3+ can form [BO4] tetrahedron and enter the silicon-oxygen network, but this effect had little impact on the frequency of Raman peaks located in the high-frequency region. Al3+ can also be coordinated by oxygen ions to form [A1O4 ] tetrahedron. [ AlO4 ] will increase the disorder degree of network while entering network. Ba2+ can increase the density of electron cloud along the Si-Onb bond when it bonds with non-bridging oxygen, which will lead to a higher peak intensity of O-Si-O stretching vibration. The Raman peaks of alkli- and alkali-earth silicate glasses are mainly distributed in the region of 400~1 200 cm-1, while in the spectrum of Na2O(K2O)-PbO-SiO2 glass system a 131 cm-1 peak existed. The authors assigned it to the Pb-O symmetric stretching vibration. Some of the samples were produced in the laboratory according to the average compositions of ancient glasses, so this research is very significant to discriminating ancient silicate glasses of different systems by Laser Raman spectroscopic technique.%运用拉曼光谱技术研究了Na2O (K2O) CaO( MgO)-SiO2,Na2O (K2O)- Al2-O3-SiO2,Na2O(K2O)-B2O3-SiO2,Na2O(K2O)-PbO-SiO2和PbO-BaO-SiO2五个系统的玻璃.结果表明,阳离子对玻璃近程结构的改造会引起拉曼特征的变化.部分样品是根据古玻璃平均成分在实验室烧制的,这项研究对于运用激光拉曼光谱区分不同系统的古代硅酸盐玻璃有重要意义.

  5. Preparation and characterization of electrically conducting polypyrrole Sn(IV phosphate cation-exchanger and its application as Mn(II ion selective membrane electrode

    Directory of Open Access Journals (Sweden)

    A.A. Khan

    2011-10-01

    Full Text Available Polypyrrole Sn(IV phosphate, an organic–inorganic composite cation-exchanger was synthesized via sol-gel mixing of an organic polymer, polypyrrole, into the matrices of the inorganic precipitate of Sn(IV phosphate. The physico-chemical properties of the material were determined using Atomic Absorption Spectrometry (AAS, CHN elemental analysis (inductively coupled plasma mass spectrometry, ICP-MS, UV–VIS spectrophotometry, FTIR (Fourier Transform Infra-Red, SEM (Scanning Electron Microscopy, TGA–DTA (Thermogravimetric Analysis–Differential Thermal Analysis, and XRD (X-ray diffraction. Ion-exchange behavior was observed to characterize the material. On the basis of distribution studies, the material was found to be highly selective for toxic heavy metal ion Mn2+. Due to its selective nature, the material was used as an electroactive component for the construction of an ion-selective membrane electrode. The proposed electrode shows fairly good discrimination of mercury ion over several other inorganic ions. The analytical utility of this electrode was established by employing it as an indicator electrode in electrometric titrations for Mn(II in water.

  6. The Significance of Glass Transition Temperature in Processing of Selected Fried Food Products: A Review

    OpenAIRE

    Abbas, K A; Ola Lasekan; Sahar K. Khalil

    2010-01-01

    This paper emphasized the significance of the glass transition temperature (Tg) by highliting its applications in drying (hot air and freeze drying) for various food systems such as skim milk powders, rice kernels, starch and sugar products and some freeze-dried products such as strawberries and surimi. The study revealed that the major components of the specified foods (which consist of mixture of ingredients), for example lactose in skim milk powder and sucrose in sugar mixtures, will influ...

  7. Selective patterning and scribing of Ti thin film on glass substrate by 532 nm picosecond laser

    Energy Technology Data Exchange (ETDEWEB)

    Yung, K.C.; Cai, Zhixiang; Choy, H.S. [Hong Kong Polytechnic University, Department of Industrial and Systems Engineering, Kowloon, Hong Kong (China)

    2012-05-15

    In this paper, the feasibility of Ti film coated on glass substrate scribed via a 532 nm picosecond laser is investigated. Laser irradiations from the film side and from the transparent substrate side are performed for comparison. Optical microscopy, SEM, surface stylus and contact resistance measurement reveal that the Ti film can be completely removed with no damage to the glass substrate, using optimized process parameters. The complete removal threshold for the film for front-side scribing is found at 120 mJ/cm{sup 2}, while the minimum laser fluence for complete scribing is 70 mJ/cm{sup 2} in the case of back-side scribing. The lines scribed from the front side exhibit obvious thermal effects such as heat affected zones, burr and micro cracks. Back-side scribing exhibits non-thermal behavior, which also can increase the process speed for the scribing of a Ti film on glass to 1000 mm/s. This makes the back-side laser scribing of Ti film a promising technique. (orig.)

  8. Devitrification kinetics and phase selection mechanisms in Cu-Zr metallic glasses

    Energy Technology Data Exchange (ETDEWEB)

    Kalay, Ilkay [Iowa State Univ., Ames, IA (United States)

    2010-01-01

    Metallic glasses have been a promising class of materials since their discovery in the 1960s. Indeed, remarkable chemical, mechanical and physical properties have attracted considerable attention, and several excellent reviews are available. Moreover, the special group of glass forming alloys known as the bulk metallic glasses (BMG) become amorphous solids even at relatively low cooling rates, allowing them to be cast in large cross sections, opening the scope of potential applications to include bulk forms and net shape structural applications. Recent studies have been reported for new bulk metallic glasses produced with lower cooling rates, from 0.1 to several hundred K/s. Some of the application products of BMGs include sporting goods, high performance springs and medical devices. Several rapid solidification techniques, including melt-spinning, atomization and surface melting have been developed to produce amorphous alloys. The aim of all these methods is to solidify the liquid phase rapidly enough to suppress the nucleation and growth of crystalline phases. Furthermore, the production of amorphous/crystalline composite (ACC) materials by partial crystallization of amorphous precursor has recently given rise to materials that provide better mechanical and magnetic properties than the monolithic amorphous or crystalline alloys. In addition, these advances illustrate the broad untapped potential of using the glassy state as an intermediate stage in the processing of new materials and nanostructures. These advances underlie the necessity of investigations on prediction and control of phase stability and microstructural dynamics during both solidification and devitrification processes. This research presented in this dissertation is mainly focused on Cu-Zr and Cu-Zr-Al alloy systems. The Cu-Zr binary system has high glass forming ability in a wide compositional range (35-70 at.% Cu). Thereby, Cu-Zr based alloys have attracted much attention according to fundamental

  9. Modification of the glass surface induced by redox reactions and internal diffusion processes

    DEFF Research Database (Denmark)

    Smedskjær, Morten Mattrup; Deubener, Joachim; Yue, Yuanzheng

    In this paper we report a novel way to modify the glass surface in favor of some physical performances. The main step is to perform iso-thermal treatments on the selected silicate glasses containing transition metal at temperatures near the glass transition temperature for various durations under...... different gases. As a result, we have observed a striking phenomenon, i.e., the outward diffusion of divalent cations occurs not only under an oxidizing atmosphere of heat-treatment, but also under nitrogen, even under reducing atmospheres like H2/N2 (10/90). The extent of the cationic diffusion depends on...... temperature and duration of heat-treatments. The mechanism of the diffusion depends on the type of the gases used for the heat-treatments. In this paper we propose several possible models describing mechanisms of the cationic diffusion, and hence, of the formation of the nano-layer. We also report the effect...

  10. The Selective Separation of Anions and Cations in Nuclear Waste Using Commercially Available Molecular Recognition Technology (MRT) Products

    Energy Technology Data Exchange (ETDEWEB)

    Izatt, S. R.; Bruening, R. L.; Krakowiak, K. E.; Izatt, R. M.

    2003-02-25

    This paper describes the use of some of IBC's SuperLig{reg_sign}, MacroLig{reg_sign}, and AnaLig{reg_sign} molecular recognition technology products to effectively and selectively separate and recover cesium, technetium, strontium, and radium from radioactive waste solutions. Distinct advantages are given over conventional separation techniques. Separations are described and results given for the target ions over chemically similar ions often present at much higher concentrations. The separations are performed in solutions of either high or low pH and usually containing high concentrations of salts. Other separations involving components of radioactive and mixed waste are noted.

  11. Complexation of trivalent cationic lanthanides by N.O donor ligands: physico-chemical studies of the association and selectivity in solution

    International Nuclear Information System (INIS)

    The aim of this work is to study the complexation of f-elements in solution by ligands incorporating N-heterocyclic donors. These ligands display interesting properties for the selective separation of An(III)/Ln(III) have been studied to obtain a better understanding of the coordination properties with f-elements and to develop more selective extractants. The hepta-dentate ligand tpaam shows an affinity for Ln(III) similar to the tetradentate ligand tpa in water even when the three additional amide groups are bonded to the metal. Even though the complexation with tpa is exothermic, that with tpaam is endothermic with a more positive entropy. The dehydration of the cation disfavours the formation of Ln(III) complexes with ligands containing weak donors. The analysis of the solution paramagnetic relaxation times of the tpaam complexes is in agreement with data in the solid-state. There is little difference between the formation constants of the Ln3+ complexes with different ligands (tpaam, tpzen, tpa and tpza) as determined by UV-vis spectrophotometry in anhydrous acetonitrile. The limitations encountered during this study are intrinsic to the ligands studied. The preliminary study of two tetrapodal ligands containing acid and pyridine groups (Lpy)or pyrazine (Lpz) show the formation of 1:1 complexes in water. Analysis of the formation constants of the corresponding Gd(III) complexes shows that replacement of a pyridine group by pyrazine result in a loss of stability of 1.6 logarithmic units. (author)

  12. Synthesis and characterisation of nitrogen poly-heterocyclic molecules using as selective complexing agents of metallic cations

    International Nuclear Information System (INIS)

    Separation of actinides (III) from lanthanides (III) is a crucial problem in the reprocessing of used nuclear fuels. Experimental results shown that soft donor extractants such as nitrogen polydentate heterocycles containing a NCCNCCN coordination site are potentials ligands for selective extraction of actinides (III). In those cases, two types of liquid-liquid extractions are employed: synergistic combination with lipophilic acid extractants and direct extraction. On the basis of the Hard and Soft Acids and Bases theory and basicity evaluation, new extractants were defined. We have first studied the synthesis of potential 1,3,5-triazine ligands designed for extraction in synergy with α-bromodecanoic acid. Secondly, we have examined the synthesis of bis-triazinyl-pyridine ligands for direct extraction studies. Extraction tests were carried out and perspectives of synthesis were deducted from those extraction results. (author)

  13. Theoretical study of the coordination behavior of formate and formamidoximate with dioxovanadium(V) cation: implications for selectivity towards uranyl.

    Science.gov (United States)

    Mehio, Nada; Johnson, J Casey; Dai, Sheng; Bryantsev, Vyacheslav S

    2015-12-21

    Poly(acrylamidoxime)-based fibers bearing random mixtures of carboxylate and amidoxime groups are the most widely utilized materials for extracting uranium from seawater. However, the competition between uranyl (UO2(2+)) and vanadium ions poses a significant challenge to the industrial mining of uranium from seawater using the current generation of adsorbents. To design more selective adsorbents, a detailed understanding of how major competing ions interact with carboxylate and amidoxime ligands is required. In this work, we employ density functional theory (DFT) and wave-function methods to investigate potential binding motifs of the dioxovanadium ion, VO2(+), with water, formate, and formamidoximate ligands. Employing higher level of theory calculations (CCSD(T)) resolve the existing controversy between the experimental results and previous DFT calculations for the structure of the hydrated VO2(+) ion. Consistent with the EXAFS data, CCSD(T) calculations predict higher stability of the distorted octahedral geometry of VO2(+)(H2O)4 compared to the five-coordinate complex with a single water molecule in the second hydration shell, while all seven tested DFT methods yield the reverse stability of the two conformations. Analysis of the relative stabilities of formate-VO2(+) complexes indicates that both monodentate and bidentate forms may coexist in thermodynamic equilibrium in solution. Investigations of VO2(+) coordination with the formamidoximate anion has revealed the existence of seven possible binding motifs, four of which are within ∼4.0 kcal mol(-1) of each other. Calculations establish that the most stable binding motif entails the coordination of oxime oxygen and amide nitrogen atoms via a tautomeric rearrangement of amidoxime to imino hydroxylamine. The difference in the most stable VO2(+) and UO2(2+) binding conformation has important implications for the design of more selective UO2(2+) ligands. PMID:26559445

  14. Mixed hemimicelles solid-phase extraction based on sodium dodecyl sulfate-coated nano-magnets for selective adsorption and enrichment of illegal cationic dyes in food matrices prior to high-performance liquid chromatography-diode array detection detection.

    Science.gov (United States)

    Qi, Ping; Liang, Zhi-an; Wang, Yu; Xiao, Jian; Liu, Jia; Zhou, Qing-qiong; Zheng, Chun-hao; Luo, Li-Ni; Lin, Zi-hao; Zhu, Fang; Zhang, Xue-wu

    2016-03-11

    In this study, mixed hemimicelles solid-phase extraction (MHSPE) based on sodium dodecyl sulfate (SDS) coated nano-magnets Fe3O4 was investigated as a novel method for the extraction and separation of four banned cationic dyes, Auramine O, Rhodamine B, Basic orange 21 and Basic orange 22, in condiments prior to HPLC detection. The main factors affecting the extraction of analysts, such as pH, surfactant and adsorbent concentrations and zeta potential were studied and optimized. Under optimized conditions, the proposed method was successful applied for the analysis of banned cationic dyes in food samples such as chili sauce, soybean paste and tomato sauce. Validation data showed the good recoveries in the range of 70.1-104.5%, with relative standard deviations less than 15%. The method limits of determination/quantification were in the range of 0.2-0.9 and 0.7-3μgkg(-1), respectively. The selective adsorption and enrichment of cationic dyes were achieved by the synergistic effects of hydrophobic interactions and electrostatic attraction between mixed hemimicelles and the cationic dyes, which also resulted in the removal of natural pigments interferences from sample extracts. When applied to real samples, RB was detected in several positive samples (chili powders) within the range from 0.042 to 0.177mgkg(-1). These results indicate that magnetic MHSPE is an efficient and selective sample preparation technique for the extraction of banned cationic dyes in a complex matrix. PMID:26877180

  15. Applying reactive models to column experiments to assess the hydrogeochemistry of seawater intrusion: Optimising ACUAINTRUSION and selecting cation exchange coefficients with PHREEQC

    Science.gov (United States)

    Boluda-Botella, N.; Valdes-Abellan, J.; Pedraza, R.

    2014-03-01

    Three sets of laboratory column experimental results concerning the hydrogeochemistry of seawater intrusion have been modelled using two codes: ACUAINTRUSION (Chemical Engineering Department, University of Alicante) and PHREEQC (U.S.G.S.). These reactive models utilise the hydrodynamic parameters determined using the ACUAINTRUSION TRANSPORT software and fit the chloride breakthrough curves perfectly. The ACUAINTRUSION code was improved, and the instabilities were studied relative to the discretisation. The relative square errors were obtained using different combinations of the spatial and temporal steps: the global error for the total experimental data and the partial error for each element. Good simulations for the three experiments were obtained using the ACUAINTRUSION software with slight variations in the selectivity coefficients for both sediments determined in batch experiments with fresh water. The cation exchange parameters included in ACUAINTRUSION are those reported by the Gapon convention with modified exponents for the Ca/Mg exchange. PHREEQC simulations performed using the Gains-Thomas convention were unsatisfactory, with the exchange coefficients from the database of PHREEQC (or range), but those determined with fresh water - natural sediment allowed only an approximation to be obtained. For the treated sediment, the adjusted exchange coefficients were determined to improve the simulation and are vastly different from those from the database of PHREEQC or batch experiment values; however, these values fall in an order similar to the others determined under dynamic conditions. Different cation concentrations were simulated using two different software packages; this disparity could be attributed to the defined selectivity coefficients that affect the gypsum equilibrium. Consequently, different calculated sulphate concentrations are obtained using each type of software; a smaller mismatch was predicted using ACUAINTRUSION. In general, the presented

  16. Effect of the nature of alkali and alkaline-earth oxides on the structure and crystallization of an alumino-borosilicate glass developed to immobilize highly concentrated nuclear waste solutions

    International Nuclear Information System (INIS)

    A complex rare-earth rich alumino-borosilicate glass has been proved to be a good candidate for the immobilization of new high level radioactive wastes. A simplified seven-oxides composition of this glass was selected for this study. In this system, sodium and calcium cations were supposed in other works to simulate respectively all the other alkali (R+ = Li+, Rb+, Cs+) and alkaline-earth (R2+ = Sr2+, Ba2+) cations present in the complex glass composition. Moreover, neodymium or lanthanum are used here to simulate all the rare-earths and actinides occurring in waste solutions. In order to study the impact of the nature of R+ and R2+ cations on both glass structure and melt crystallization tendency during cooling, two glass series were prepared by replacing either Na+ or Ca2+ cations in the simplified glass by respectively (Li+, K+, Rb+, Cs+) or (Mg2+, Sr2+, Ba2+) cations. From these substitutions, it was established that alkali ions are preferentially involved in the charge compensation of (AlO4)- entities in the glass network comparatively to alkaline-earth ions. The glass compositions containing calcium give way to the crystallization of an apatite silicate phase bearing calcium and rare-earth ions. The melt crystallization tendency during cooling strongly varies with the nature of the alkaline-earth. (authors)

  17. Cation-selective extraction column study for the conception of nuclear medical radionuclide generators; Untersuchung kationenselektiver Extraktionssaeulen zur Konzeption nuklearmedizinischer Radionuklidgeneratoren

    Energy Technology Data Exchange (ETDEWEB)

    Streng, Roman

    2012-07-09

    The topic of the present work is the conception of a Yttrium-90 radionuclide generator for nuclear medicine applications. Due to its physical properties Yttrium-90 is considered as one of the most useful nuclides for radiotherapeutic cancer treatment. The parent nuclide Strontium-90 is gained during reprocessing of fission products. Thus, the sustained availability of large quantities of Yttrium-90 is limited to a number of research facilities. A radionuclide generator provides an independent Yttrium-90 source and enhances the capacities for radiopharmaceutical research and biomedical applications. The present work focussed on the identification of appropriate column materials for the separation of Strontium and Yttrium. The results for two materials are reported: AnaLig {sup registered} Sr-01 and crystalline antimonic acid. Based on the mode of operation of the Technetium-99m generator the aim was to enable the construction of a compact, enclosed apparatus. The projected device comprises a reservoir for the eluant, the ion-exchange column, pipings and radiation shielding. Elution of Yttrium-90 could then be easily performed by connecting evacuated vials to the outlet tube. The prospected concept involves physical and chemical confinements that exclude most of the known processes for Strontium-Yttrium separation. For example no ligands, no oxidizing reactants (e.g. nitric acid) and no organic solvents are to be used, but small volumes of isotonic or buffer solutions and dilute acids respectively. AnaLig {sup registered} Sr-01 is a commercially available resin used in extraction chromatography. Its high selectivity for Strontium cations results from the strictly defined cavity of the imbedded cryptand. Determination of weight distribution coefficients, elution studies and pre-generator experiments were carried out. Quantitative separation of Yttrium from Strontium and Zirconium is possible using small volumes of 0,05 M hydrochloric acid as eluant. Furthermore, high

  18. Fixation by ion exchange of toxic materials in a glass matrix

    International Nuclear Information System (INIS)

    A process for disposing of toxic materials such as radioactive waste comprises reacting a porous silicate glass or silica gel, having interconnected pores and alkali metal cations. Group 1b metal cations and/or ammonium cation bonded to silicon through divalent oxygen linkages on the internal surfaces of said pores, with a toxic material containing toxic cations as well as non-cationic portions. The toxic cations are capable of displacing the alkali metal cations, Group 1b metal cations and/or ammonium cations to provide a distribution of internal silicon-bonded toxic cation oxide groups within the pores of the glass or silica gel. (author)

  19. A production attempt of selected metallic glasses with Fe and Ni matrix

    Directory of Open Access Journals (Sweden)

    W. Pilarczyk

    2010-01-01

    Full Text Available Design/methodology/approach: The studies were carried out on bulk metallic materials as rods. The rods of the Fe57.6Co7.2Ni7.2B19.2Si4.8Nb4 and Ni64.8Co7.2B19.2Si4.8Nb4 alloys were obtained by the pressure die casting. In order to investigate the structure scanning electron microscopy were used. Phase composition of obtained rods was determined by means of diffractometer. The thermal properties of the studied alloys were examined by differential thermal analysis and differential scanning calorimetry.Findings: The x-ray analysis, microscopic observation and thermal examination revealed that the studied as-cast bulk metallic materials were of amorphous, crystalline and mixed structure. Broad diffraction halo can be seen for rods with diameter of ø=1.5 and 2mm of Fe57.6Co7.2Ni7.2B19.2Si4.8Nb4 alloy. The replacement of Fe by Ni created crystalline structure.Practical implications: Fe- and Ni-based bulk metallic glass systems have been developed because they offer great potential for commercial application. Fe-based ferromagnetic bulk glassy alloys exhibit great magnetic properties. It is very important for their magnetic applications. That alloys can be used as soft electro-magnetic cores for choke coil or noise filter. Ni-based bulk metallic glasses exhibit excellent mechanical properties and corrosion resistance.Originality/value: The formation and studies of the casted Fe- and Ni-based bulk materials and investigation of the effectiveness of the replacement of Fe by Ni.

  20. Changes in cationic selectivity of the nicotinic channel at the rat ganglionic synapse: a role for chloride ions?

    Directory of Open Access Journals (Sweden)

    Oscar Sacchi

    Full Text Available The permeability of the nicotinic channel (nAChR at the ganglionic synapse has been examined, in the intact rat superior cervical ganglion in vitro, by fitting the Goldman current equation to the synaptic current (EPSC I-V relationship. Subsynaptic nAChRs, activated by neurally-released acetylcholine (ACh, were thus analyzed in an intact environment as natively expressed by the mature sympathetic neuron. Postsynaptic neuron hyperpolarization (from -40 to -90 mV resulted in a change of the synaptic potassium/sodium permeability ratio (P(K/P(Na from 1.40 to 0.92, corresponding to a reversible shift of the apparent acetylcholine equilibrium potential, E(ACh, by about +10 mV. The effect was accompanied by a decrease of the peak synaptic conductance (g(syn and of the EPSC decay time constant. Reduction of [Cl(-](o to 18 mM resulted in a change of P(K/P(Na from 1.57 (control to 2.26, associated with a reversible shift of E(ACh by about -10 mV. Application of 200 nM αBgTx evoked P(K/P(Na and g(syn modifications similar to those observed in reduced [Cl(-](o. The two treatments were overlapping and complementary, as if the same site/mechanism were involved. The difference current before and after chloride reduction or toxin application exhibited a strongly positive equilibrium potential, which could not be explained by the block of a calcium component of the EPSC. Observations under current-clamp conditions suggest that the driving force modification of the EPSC due to P(K/P(Na changes represent an additional powerful integrative mechanism of neuron behavior. A possible role for chloride ions is suggested: the nAChR selectivity was actually reduced by increased chloride gradient (membrane hyperpolarization, while it was increased, moving towards a channel preferentially permeable for potassium, when the chloride gradient was reduced.

  1. Determination of Nicotine in Tobacco by Chemometric Optimization and Cation-Selective Exhaustive Injection in Combination with Sweeping-Micellar Electrokinetic Chromatography

    Directory of Open Access Journals (Sweden)

    Yi-Hui Lin

    2015-01-01

    Full Text Available Nicotine is a potent chemical that excites the central nervous system and refreshes people. It is also physically addictive and causes dependence. To reduce the harm of tobacco products for smokers, a law was introduced that requires tobacco product containers to be marked with the amount of nicotine as well as tar. In this paper, an online stacking capillary electrophoresis (CE method with cation-selective exhaustive injection sweeping-micellar electrokinetic chromatography (CSEI-sweeping-MEKC is proposed for the optimized analysis of nicotine in tobacco. A higher conductivity buffer (160 mM phosphate buffer (pH 3 zone was injected into the capillary, allowing for the analytes to be electrokinetically injected at a voltage of 15 kV for 15 min. Using 50 mM sodium dodecyl sulfate and 25% methanol in the sweeping buffer, nicotine was detected with high sensitivity. Thus, optimized conditions adapted from a chemometric approach provided a 6000-fold increase in the nicotine detection sensitivity using the CSEI-sweeping-MEKC method in comparison to normal CZE. The limits of detection were 0.5 nM for nicotine. The stacking method in combination with direct injection which matrix components would not interfere with assay performance was successfully applied to the detection of nicotine in tobacco samples.

  2. Selective sorption of lead, cadmium and zinc ions by a polymeric cation exchanger containing nano-Zr(HPO3S)2.

    Science.gov (United States)

    Zhang, Qingrui; Pan, Bingcai; Pan, Bingjun; Zhang, Weiming; Jia, Kun; Zhang, Quanxing

    2008-06-01

    A novel polymeric hybrid sorbent, namely ZrPS-001, was fabricated for enhanced sorption of heavy metal ions by impregnating Zr(HPO3S)2 (i.e., ZrPS) nanoparticles within a porous polymeric cation exchanger D-001. The immobilized negatively charged groups bound to the polymeric matrix D-001 would result in preconcentration and permeation enhancement of target metal ions prior to sequestration, and ZrPS nanoparticles are expected to sequester heavy metals selectively through an ion-exchange process. Highly effective sequestration of lead, cadmium, and zinc ions from aqueous solution can be achieved by ZrPS-001 even in the presence of competing calcium ion at concentration several orders of magnitude greater than the target species. The exhausted ZrPS-001 beads are amenable to regeneration with 6 M HCI solution for repeated use without any significant capacity loss. Fixed-bed column treatment of simulated waters containing heavy metals at high or trace levels was also performed. The content of heavy metals in treated effluent approached or met the WHO drinking water standard. PMID:18589978

  3. Cation-selective exhaustive injection and sweeping micellar electrokinetic chromatography for the analysis of methadone and its metabolites in serum of heroin addicts.

    Science.gov (United States)

    Wang, Chun-Chi; Chen, Cheng-Chung; Wang, Shang-Jang; Wu, Shou-Mei

    2011-09-23

    Methadone (MET) metabolism has been largely demonstrated with a high inter-individual variability and, therefore, quantification of MET is very important for therapeutic drug monitoring. A cation-selective exhaustive injection and sweeping MEKC (CSEI-Sweeping) was first developed to analyze MET and its two metabolites, 2-ethylidene-1,5-dimethyl-3,3-diphenylpyrrolidine (EDDP) and 2-ethyl-5-methyl-3,3-diphenyl-1-pyrroline (EMDP), in human serum. After pretreatment, the samples were electrokinetically injected into capillary (10 kV, 500s) and swept by the separation phosphate buffer (100 mM, pH 4.0) containing 20% tetrahydrofuran and 100 mM SDS at -15 kV. The LODs were 200 pg/mL for MET and EMDP, and 400 pg/mL for EDDP. Ten volunteers were administered MET (5.0-120.0 mg/day) orally for 84 days and serum samples were taken after the daily dose of MET (days 1, 2, 7, 14, 28, 56 and 84) individually. This method was used for monitoring MET and its metabolites in heroin addicts and for pharmacokinetic investigations. PMID:21862022

  4. Evaluation of the combination of micellar electrokinetic capillary chromatography with sweeping and cation selective exhaustive injection for the determination of 5-nitroimidazoles in egg samples.

    Science.gov (United States)

    Airado-Rodríguez, Diego; Hernández-Mesa, Maykel; García-Campaña, Ana M; Cruces-Blanco, Carmen

    2016-12-15

    A methodology is presented for the sensitive determination of nitromidazole residues in egg by means of micellar electrokinetic capillary chromatography in combination with cation selective exhaustive injection and ultraviolet detection. Six compounds have been considered and the separation has been achieved in less than 12min in a 61.5-cm effective length capillary with 50-μm internal diameter. Phosphate buffer 44mM pH 2.5, containing 8% tetrahydrofurane and 123mM sodium dodecyl sulfate was employed as running buffer. Solid phase extraction has been employed for sample clean-up. The methodology has been successfully validated in hen eggs, obtaining method detection limits in the range of 2.1-5.0ng/g. Precision was studied in terms of repeatability and intermediate precision, with relative standard deviations lower than 18.0%. Recoveries were calculated in quail eggs and a commercial pasteurized egg white product, reaching over 70% for most of the considered 5-nitroimidazoles. PMID:27451174

  5. Investigations of glass structure using fluorescence line narrowing and moleuclar dynamics simulations

    International Nuclear Information System (INIS)

    The local structure at individual ion sites in simple and multicomponent glasses is simulated using methods of molecular dynamics. Computer simulations of fluoroberyllate glasses predict a range of ion separations and coordination numbers that increases with increasing complexity of the glass composition. This occurs at both glass forming and glass modifying cation sites. Laser-induced fluorescence line-narrowing techniques provide a unique probe of the local environments of selected subsets of ions and are used to measure site to site variations in the electronic energy levels and transition probabilities of rare earth ions. These and additional results from EXAFS, neutron and x-ray diffraction, and NMR experiments are compared with simulated glass structures

  6. Bio-active glass air-abrasion has the potential to remove resin composite restorative material selectively

    International Nuclear Information System (INIS)

    The aims of this study were to assess: (a) the chemistry, morphology and bioactivity of bio-active glass (BAG) air-abrasive powder, (b) the effect of three air-abrasion operating parameters: air pressure, powder flow rate (PFR) and the abrasive powder itself, on the selective removal of resin composite and (c) the required “time taken”. BAG abrasive particles were characterised using scanning electron microscopy-energy dispersive X-ray spectrometry (SEM-EDX) and Fourier-transform infrared spectroscopy (FTIR). Standardised resin composite restorations created within an enamel analogue block (Macor™) in vitro, were removed using air-abrasion undersimulated clinical conditions. 90 standardised cavities were scanned before and after resin composite removal using laser profilometry and the volume of the resulting 3D images calculated. Multilevel linear model was used to identify the significant factors affecting Macor™ removal. BAG powder removed resin composite more selectively than conventional air-abrasion alumina powder using the same operating parameters (p < 0.001) and the effect of altering the unit's operating parameters was significant (p < 0.001). In conclusion, BAG powder is more efficient than alumina in the selective removal of resin composite particularly under specific operating parameters, and therefore may be recommended clinically as a method of preserving sound enamel structure when repairing and removing defective resin composite restorations.

  7. Bio-active glass air-abrasion has the potential to remove resin composite restorative material selectively

    Science.gov (United States)

    Milly, Hussam; Andiappan, Manoharan; Thompson, Ian; Banerjee, Avijit

    2014-06-01

    The aims of this study were to assess: (a) the chemistry, morphology and bioactivity of bio-active glass (BAG) air-abrasive powder, (b) the effect of three air-abrasion operating parameters: air pressure, powder flow rate (PFR) and the abrasive powder itself, on the selective removal of resin composite and (c) the required “time taken”. BAG abrasive particles were characterised using scanning electron microscopy-energy dispersive X-ray spectrometry (SEM-EDX) and Fourier-transform infrared spectroscopy (FTIR). Standardised resin composite restorations created within an enamel analogue block (Macor™) in vitro, were removed using air-abrasion undersimulated clinical conditions. 90 standardised cavities were scanned before and after resin composite removal using laser profilometry and the volume of the resulting 3D images calculated. Multilevel linear model was used to identify the significant factors affecting Macor™ removal. BAG powder removed resin composite more selectively than conventional air-abrasion alumina powder using the same operating parameters (p < 0.001) and the effect of altering the unit's operating parameters was significant (p < 0.001). In conclusion, BAG powder is more efficient than alumina in the selective removal of resin composite particularly under specific operating parameters, and therefore may be recommended clinically as a method of preserving sound enamel structure when repairing and removing defective resin composite restorations.

  8. Bio-active glass air-abrasion has the potential to remove resin composite restorative material selectively

    Energy Technology Data Exchange (ETDEWEB)

    Milly, Hussam [Biomaterials, Biomimetics and Biophotonics Research Group, Kings College London Dental Institute at Guy' s Hospital, King' s Health Partners, London (United Kingdom); Andiappan, Manoharan [Unit of Dental Public Health, Kings College London Dental Institute at Guy' s Hospital, King' s Health Partners, London (United Kingdom); Thompson, Ian [Biomaterials, Biomimetics and Biophotonics Research Group, Kings College London Dental Institute at Guy' s Hospital, King' s Health Partners, London (United Kingdom); Banerjee, Avijit, E-mail: avijit.banerjee@kcl.ac.uk [Biomaterials, Biomimetics and Biophotonics Research Group, Kings College London Dental Institute at Guy' s Hospital, King' s Health Partners, London (United Kingdom); Unit of Conservative Dentistry, King' s College London Dental Institute at Guy' s Hospital, King' s Health Partners, London (United Kingdom)

    2014-06-01

    The aims of this study were to assess: (a) the chemistry, morphology and bioactivity of bio-active glass (BAG) air-abrasive powder, (b) the effect of three air-abrasion operating parameters: air pressure, powder flow rate (PFR) and the abrasive powder itself, on the selective removal of resin composite and (c) the required “time taken”. BAG abrasive particles were characterised using scanning electron microscopy-energy dispersive X-ray spectrometry (SEM-EDX) and Fourier-transform infrared spectroscopy (FTIR). Standardised resin composite restorations created within an enamel analogue block (Macor™) in vitro, were removed using air-abrasion undersimulated clinical conditions. 90 standardised cavities were scanned before and after resin composite removal using laser profilometry and the volume of the resulting 3D images calculated. Multilevel linear model was used to identify the significant factors affecting Macor™ removal. BAG powder removed resin composite more selectively than conventional air-abrasion alumina powder using the same operating parameters (p < 0.001) and the effect of altering the unit's operating parameters was significant (p < 0.001). In conclusion, BAG powder is more efficient than alumina in the selective removal of resin composite particularly under specific operating parameters, and therefore may be recommended clinically as a method of preserving sound enamel structure when repairing and removing defective resin composite restorations.

  9. Vibronic spectra of Gd3+ in metaphosphate glasses: Comparison with Raman and infrared spectra

    International Nuclear Information System (INIS)

    Vibronic sidebands associated with the 6P/sub 7/2/→8S/sub 7/2/ transition of Gd3+-doped metaphosphate glasses are observed using line-narrowed fluorescence techniques. Glasses having metal cations of different mass and charge (La,Al,Mg,Ba) are examined. Vibronic spectra, which probe vibrations about the rare-earth element site, are compared with polarized Raman scattering data and the infrared dielectric constant obtained from near-normal reflectance measurements. Results indicate that in metaphosphate glasses vibronic selection rules are similar to HV (vertical height) Raman selection rules. The wavelengths and relative intensities of peaks in the high-frequency portion of the vibronic spectra change with respect to corresponding peaks in the Raman spectra when the mass and/or charge of Gd3+ differs significantly from that of the metal cation

  10. Site-selective spectroscopy in Sm3+-doped sol-gel-derived nano-glass-ceramics containing SnO2 quantum dots

    International Nuclear Information System (INIS)

    Nano-glass-ceramics of composition 95SiO2-5SnO2 doped with 0.4 Sm3+ (mol%) were synthesized by the thermal treatment of precursor sol-gel glasses. Structural and luminescence measurements were carried out. The precipitated SnO2 nanocrystals in the glass matrix constitute a wide bandgap quantum-dot system with size comparable to the bulk exciton Bohr radius. A site-selective excitation, by energy transfer from the semiconductor host, reveals that a fraction of the Sm3+ ions are incorporated in the SnO2 nanocrystals, whereas the rest remains in the silica glassy phase. An evolution in the Sm3+ emission spectra has been observed when the SnO2 nanocrystals are excited with different UV wavelengths, which has been ascribed to selective excitation of nanocrystal sets with predetermined size

  11. Site-selective spectroscopy in Sm{sup 3+}-doped sol-gel-derived nano-glass-ceramics containing SnO{sub 2} quantum dots

    Energy Technology Data Exchange (ETDEWEB)

    Yanes, A C; Castillo, J del [Departamento de Fisica Basica, Universidad de La Laguna, E-38206 La Laguna, Tenerife (Spain); Velazquez, J J; Mendez-Ramos, J; RodrIguez, V D [Departamento de Fisica Fund. y Experimental, Universidade La Laguna, E-38206 La Laguna, Tenerife (Spain)], E-mail: ayanesh@ull.es, E-mail: vrguez@ull.es

    2008-07-23

    Nano-glass-ceramics of composition 95SiO{sub 2}-5SnO{sub 2} doped with 0.4 Sm{sup 3+} (mol%) were synthesized by the thermal treatment of precursor sol-gel glasses. Structural and luminescence measurements were carried out. The precipitated SnO{sub 2} nanocrystals in the glass matrix constitute a wide bandgap quantum-dot system with size comparable to the bulk exciton Bohr radius. A site-selective excitation, by energy transfer from the semiconductor host, reveals that a fraction of the Sm{sup 3+} ions are incorporated in the SnO{sub 2} nanocrystals, whereas the rest remains in the silica glassy phase. An evolution in the Sm{sup 3+} emission spectra has been observed when the SnO{sub 2} nanocrystals are excited with different UV wavelengths, which has been ascribed to selective excitation of nanocrystal sets with predetermined size.

  12. 1H and 23Na MAS NMR spectroscopy of cationic species in CO2 selective alkaline earth metal porous silicoaluminophosphates prepared via liquid and solid state ion exchange

    Science.gov (United States)

    Arévalo-Hidalgo, Ana G.; Dugar, Sneha; Fu, Riqiang; Hernández-Maldonado, Arturo J.

    2012-07-01

    The location of extraframework cations in Sr2+ and Ba2+ ion-exchanged SAPO-34 was estimated by means of 1H and 23Na MAS NMR spectroscopy and spectral deconvolution. Incorporation of the alkaline earth metal cations onto the SAPO framework was achieved via liquid state ion exchange, coupled partial detemplation/solid-state ion exchange, and combination of both techniques. MAS NMR revealed that the level of ion exchange was limited by the presence of protons and sodium cations near hexagonal prisms (site SI), which are relatively difficult to exchange with the alkaline earth metal due to steric and charge repulsion criteria. In addition, the presence of ammonium cations in the supercages facilitated the exchange of otherwise tenacious hydrogen as corroborated by unit cell compositional data as well as enhanced CO2 adsorption at low partial pressures. The extraframework ammonium species were produced from partial detemplation of the structure-directing agent employed for the SAPO-34 synthesis, tetraethylammonium.

  13. 1H and 23Na MAS NMR spectroscopy of cationic species in CO2 selective alkaline earth metal porous silicoaluminophosphates prepared via liquid and solid state ion exchange

    International Nuclear Information System (INIS)

    The location of extraframework cations in Sr2+ and Ba2+ ion-exchanged SAPO-34 was estimated by means of 1H and 23Na MAS NMR spectroscopy and spectral deconvolution. Incorporation of the alkaline earth metal cations onto the SAPO framework was achieved via liquid state ion exchange, coupled partial detemplation/solid-state ion exchange, and combination of both techniques. MAS NMR revealed that the level of ion exchange was limited by the presence of protons and sodium cations near hexagonal prisms (site SI), which are relatively difficult to exchange with the alkaline earth metal due to steric and charge repulsion criteria. In addition, the presence of ammonium cations in the supercages facilitated the exchange of otherwise tenacious hydrogen as corroborated by unit cell compositional data as well as enhanced CO2 adsorption at low partial pressures. The extraframework ammonium species were produced from partial detemplation of the structure-directing agent employed for the SAPO-34 synthesis, tetraethylammonium. - Graphical abstract: MAS NMR was used to elucidate the position the cationic species in alkaline earth metal exchanged silicoaluminophosphates. These species played a significant role during the ion exchange process and, therefore, the materials ultimate CO2 adsorption performance. Highlights: ► Location of extraframework Sr2+ or Ba2+ cations was estimated by means of 1H and 23Na MAS NMR. ► Level of Sr2+ or Ba2+ ion exchange was limited by the presence of protons and sodium cations. ► Presence of ammonium cations in the supercages facilitated the exchange. ► Sr2+ and Ba2+ ion exchanged SAPOs are outstanding CO2 adsorbents.

  14. 64Cu-Labeled 2-(Diphenylphosphoryl)ethyldiphenylphosphonium Cations as Highly Selective Tumor Imaging Agents: Effects of Linkers and Chelates on Radiotracer Biodistribution Characteristics

    OpenAIRE

    Yang, Chang-Tong; Kim, Young-Seung; Wang, Jianjun; WANG, LIJUN; Shi, Jiyun; Li, Zi-bo; Chen, Xiaoyuan; Fan, Ming; Li, Jian-Jian; Liu, Shuang

    2008-01-01

    Radiolabeled organic cations, such as triphenylphosphonium (TPP), represents a new class of radiotracers for imaging cancers and the transport function of multidrug resistance P-glycoproteins (particularly MDR1 Pgp) by single photon emission computed tomography (SPECT) or positron emission tomography (PET). This report presents the synthesis and biological evaluation of 64Cu-labeled 2-(diphenylphosphoryl)ethyldiphenylphosphonium (TPEP) cations as novel PET radiotracers for tumor imaging. Biod...

  15. Dowex anion exchanger-loaded-baker's yeast as bi-functionalized biosorbents for selective extraction of anionic and cationic mercury(II) species

    International Nuclear Information System (INIS)

    Dowex anion exchanger-immobilized-baker's yeast [Dae-yeast] were synthesized and potentially applied as environmental friendly biosorbents to evaluate the up-take process of anionic and cationic mercury(II) species as well as other metal ions. Optimization of mass ratio of Dowex anion exchanger versus yeast (1:1-1:10) in presence of various interacting buffer solutions (pH 4.0-9.0) was performed and evaluated. Surface modification of [Dae-yeast] was characterized by scanning electron microscopy (SEM) and infrared spectroscopy. The maximum metal biosorption capacity values of [Dae-yeast] towards mercury(II) were found in the range of 0.800-0.960, 0.840-0.950 and 0.730-0.900 mmol g-1 in presence of buffer solutions pH 2.0, 4.0 and 7.0, respectively. Three possible and different mechanisms are proposed to account for the biosorption of mercury and mercuric species under these three buffering conditions based on ion exchange, ion pair and chelation interaction processes. Factors affecting biosorption of mercury from aqueous medium including the pH effect of aqueous solutions (1.0-7.0), shaking time (1-30 min) and interfering ions were searched. The potential applications of modified biosorbents for selective biosorption and extraction of mercury from different real matrices including dental filling waste materials, industrial waste water samples and mercury lamp waste materials were also explored. The results denote to excellent percentage extraction values, from nitric acid as the dissolution solvent with a pH 2.0, as determined in the range of 90.77-97.91 ± 3.00-5.00%, 90.00-93.40 ± 4.00-5.00% and 92.31-100.00 ± 3.00-4.00% for the three tested samples, respectively.

  16. Influence of material selection and fabrication process repeatability on mechanical properties of glass-polymer matrix composite structures

    Science.gov (United States)

    Edwards, Charles

    This study has aimed to evaluate property uniformity from data obtained utilizing one design of a single layup composite plaque, three sources of glass fibers and a single, industry accepted resin to produce a repeatable fabrication process. This thesis has investigated the following: (1) Whether the type of glass (E-Glass, S-Glass, and R-Glass) influences the property values of individually tested samples compared between glass types. (2) Whether the type of glass influences the property uniformity throughout the set of tested samples. (3) Whether the composite plaque design and resulting performance, as defined by ASTM Standards or industry accepted parameters, is adequate for use in the defined military application or wind specific application. The resulting data showed trends that established the relationship between the mechanical properties of the materials used in constructing the composites and the properties of fabricated composite test plaques. The S-glass resulted in the highest ultimate fracture strength and modulus, yet had the highest properties per cost value. The E-glass demonstrated the worst mechanical properties of the three grades, however had the highest value comparing properties to cost. All of the composites were fabricated at <2% void content and considered a quality test sample.

  17. Liquid-solid extraction of cationic metals by cationic amphiphiles

    International Nuclear Information System (INIS)

    In the field of selective separation for recycling of spent nuclear fuel, liquid-liquid extraction processes are widely used (PUREX, DIAMEX..) in industrial scale. In order to guarantee a sustainable nuclear energy for the forthcoming generations, alternative reprocessing techniques are under development. One of them bases on the studies from Heckmann et al in the 80's and consists in selectively precipitating actinides from aqueous waste solutions by cationic surfactants (liquid-solid extraction). This technique has some interesting advantages over liquid-liquid extraction techniques, because several steps are omitted like stripping or solvent washing. Moreover, the amount of waste is decreased considerably, since no contaminated organic solvent is produced. In this thesis, we have carried out a physico-chemical study to understand the specific interactions between the metallic cations with the cationic surfactant. First, we have analysed the specific effect of the different counter-ions (Cl-, NO3-, C2O42-) and then the effect of alkaline cations on the structural properties of the surfactant aggregation in varying thermodynamical conditions. Finally, different multivalent cations (Cu2+, Zn2+, UO22+, Fe3+, Nd3+, Eu3+, Th4+) were considered; we have concluded that depending on the anionic complex of these metals formed in acidic media, we can observe either an adsorption at the micellar interface or not. This adsorption has a large influence of the surfactant aggregation properties and determines the limits of the application in term of ionic strength, temperature and surfactant concentration. (author)

  18. A Ferrocene-Quinoxaline Derivative as a Highly Selective Probe for Colorimetric and Redox Sensing of Toxic Mercury(II Cations

    Directory of Open Access Journals (Sweden)

    Antonio Caballero

    2010-12-01

    Full Text Available A new chemosensor molecule 3 based on a ferrocene-quinoxaline dyad recognizes mercury (II cations in acetonitrile solution. Upon recognition, an anodic shift of the ferrocene/ferrocenium oxidation peaks and a progressive red-shift (Δλ = 140 nm of the low-energy band, are observed in its absorption spectrum. This change in the absorption spectrum is accompanied by a colour change from orange to deep green, which can be used for a “naked-eye” detection of this metal cation.

  19. Spatially selected synthesis of LaF3 and Er3+-doped CaF2 crystals in oxyfluoride glasses by laser-induced crystallization

    International Nuclear Information System (INIS)

    Oxyfluoride glasses with a small amount of NiO are prepared using a conventional melt quenching technique, and the spatially selected crystallization of LaF3 and CaF2 crystals is induced on the glass surface by irradiations of continuous wave lasers with a wavelength of λ=1064 or 1080 nm. Dots and lines including LaF3 crystals are patterned by heat-assisted (300 deg. C) laser irradiations (λ=1064 nm) with a power of P=1 W and an irradiation time of 10 s for dots and a scanning speed of S=5 μm/s for lines. Lines consisting of CaF2 crystals are also patterned in an ErF3-doped oxyfluoride glass by laser irradiations (λ=1080 nm) with a power of P=1.7 W and a scanning speed of S=2 μm/s, and the incorporation of Er3+ ions into CaF2 crystals is confirmed from micro-photoluminescence spectrum measurements. It is proposed that the lines patterned by laser irradiations in this study are consisted of the composite of LaF3 or CaF2 nanocrystals and SiO2-based oxide glassy phase. It is demonstrated that a combination of Ni2+-dopings and laser irradiations is effective in spatially selected local crystallizations of fluorides in oxyfluoride glasses. - Graphical abstract: This figure shows the polarization optical and confocal scanning laser micrographs for lines obtained by laser irradiations with a laser power of P=1.7 W and a scanning speed of S=2 μm/s in an oxyfluoride glass. It is proposed that the line consists of the composite of CaF2 nanocrystals and oxide glassy phase. This is the first demonstration on the patterning of fluoride crystals in glass by laser irradiations

  20. Ruminal and Abomasal Starch Hydrolysate Infusions Selectively Decrease the Expression of Cationic Amino Acid Transporter mRNA by Small Intestinal Epithelia of Forage-fed Beef Steers

    Science.gov (United States)

    Although cationic amino acids (CAA) are consid-ered essential to maximize optimal growth of cattle, transporters responsible for CAA absorption by bovine small intestinal epithelia have not been described. This study was conducted to test 2 hypotheses: 1) the duo¬denal, jejunal, and ileal epithelia ...

  1. Lap shear strength of selected adhesives (epoxy, varnish, B-stage glass cloth) in liquid nitrogen and at room temperature

    International Nuclear Information System (INIS)

    The adhesives included several epoxy resins, a varnish, and a B-stage glass cloth (a partially cured resin in a fiberglass cloth matrix). Several parameters critical to bond strength were varied: adhesive and adherend differences, surface preparation, coupling agents, glass cloth, epoxy thickness, fillers, and bonding pressure and temperature. The highest lap shear strengths were obtained with the B-shear glass cloth at both liquid nitrogen and room temperatures with values of approximately 20 MPa (3000 psi) and approximately 25.5 MPa (3700 psi) respectively

  2. Effect of major cation water composition on the ion exchange of Np(V) on montmorillonite: NpO2+–Na+–K+–Ca2+–Mg2+ selectivity coefficients

    International Nuclear Information System (INIS)

    Highlights: • Determined Np(V)-montmorillonite ion exchange constant, applicable in a wide range of conditions. • Developed a model for Np(V) ion exchange which can be readily applied in thermodynamic databases. • Identified solution conditions at which Np(V) ion exchange will play a significant role. - Abstract: Np(V) sorption was examined in pH 4.5 colloidal suspensions of nominally homoionic montmorillonite (Na-, K-, Ca- and Mg-montmorillonite). Ionic exchange on permanent charge sites was studied as a function of ionic strength (0.1, 0.01 and 0.001 M) and background electrolyte (NaCl, KCl, CaCl2 and MgCl2). An ion exchange model was developed using the FIT4FD program, which considered all experimental data simultaneously: Np sorption data, major cation composition of the electrolyte and associated uncertainties. The model was developed to be consistent with the ion exchange selectivity coefficients between the major cations reported in the literature and led to the following recommended selectivity coefficients for Np(V) ion exchange according to the Vanselow convention: log(NpO2+Na+KV)=-0.20,log(NpO2+K+KV)=-0.46,log(NpO2+Ca2+KV)=-0.57,log (NpO2+Mg2+KV)=-0.57. Both the experimental data and the estimated selectivity coefficients in this study are consistent with the limited Np(V) ion exchange and sorption data reported in the literature. The results indicate that, as expected, low ionic strengths favor Np(V) sorption when ion exchange is the main sorption mechanism (i.e. acidic to neutral pHs) and that the divalent cations Ca2+ and Mg2+ may be important in limiting Np(V) ionic exchange on montmorillonite

  3. Selective formation of GaN-based nanorod heterostructures on soda-lime glass substrates by a local heating method

    International Nuclear Information System (INIS)

    We report on the fabrication of high-quality GaN on soda-lime glass substrates, heretofore precluded by both the intolerance of soda-lime glass to the high temperatures required for III-nitride growth and the lack of an epitaxial relationship with amorphous glass. The difficulties were circumvented by heteroepitaxial coating of GaN on ZnO nanorods via a local microheating method. Metal-organic chemical vapor deposition of ZnO nanorods and GaN layers using the microheater arrays produced high-quality GaN/ZnO coaxial nanorod heterostructures at only the desired regions on the soda-lime glass substrates. High-resolution transmission electron microscopy examination of the coaxial nanorod heterostructures indicated the formation of an abrupt, semicoherent interface. Photoluminescence and cathodoluminescence spectroscopy was also applied to confirm the high optical quality of the coaxial nanorod heterostructures. Mg-doped GaN/ZnO coaxial nanorod heterostructure arrays, whose GaN shell layers were grown with various different magnesocene flow rates, were further investigated by using photoluminescence spectroscopy for the p-type doping characteristics. The suggested method for fabrication of III-nitrides on glass substrates signifies potentials for low-cost and large-size optoelectronic device applications.

  4. Baseline LAW Glass Formulation Testing

    Energy Technology Data Exchange (ETDEWEB)

    Kruger, Albert A. [USDOE Office of River Protection, Richland, WA (United States); Mooers, Cavin [The Catholic University of America, Washington, DC (United States). Vitreous State Lab.; Bazemore, Gina [The Catholic University of America, Washington, DC (United States). Vitreous State Lab; Pegg, Ian L. [The Catholic University of America, Washington, DC (United States). Vitreous State Lab; Hight, Kenneth [The Catholic University of America, Washington, DC (United States). Vitreous State Lab; Lai, Shan Tao [The Catholic University of America, Washington, DC (United States). Vitreous State Lab; Buechele, Andrew [The Catholic University of America, Washington, DC (United States). Vitreous State Lab; Rielley, Elizabeth [The Catholic University of America, Washington, DC (United States). Vitreous State Lab; Gan, Hao [The Catholic University of America, Washington, DC (United States). Vitreous State Lab; Muller, Isabelle S. [The Catholic University of America, Washington, DC (United States). Vitreous State Lab; Cecil, Richard [The Catholic University of America, Washington, DC (United States). Vitreous State Lab

    2013-06-13

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

  5. On the selective deposition of tin and tin oxide on various glasses using a high power diode laser

    OpenAIRE

    Lawrence, Jonathan; Lubrani, Peter; Li, Lin

    2001-01-01

    The deposition of SnO2 using a 120 W high power diode laser (HPDL) on both fused silica and soda-lime-silica glass has been successfully demonstrated. Deposition on both glass substrates was carried out with laser power densities of 650-1600 W cm-2 and at rates of 420-1550 mm min-1. The thickness of the deposited layers was typically around 250 m. The maximum theoretical coverage rate that it may be possible to achieve using the HPDL was calculated as being 3.72 m2 h-1. Owing to the wettabil...

  6. Synthesis and studies of selective chemosensor for naked-eye detection of anions and cations based on a new Schiff-base derivative.

    Science.gov (United States)

    Orojloo, Masoumeh; Amani, Saeid

    2016-10-01

    A new chromogenic receptor, 4-((2,4-dichlorophenyl)diazenyl)-2-(3-hydroxypropylimino) methyl)phenol, has been designed and synthesized for quantitative and low-cost detection of various biological anions and cations. The dye was characterized by elemental analyses, infrared, UV-visible spectroscopy, and NMR spectroscopy. Upon the addition of F(-) and H2PO4(-) to the solution of chemosensor in DMSO, the dramatic naked eye detectable color changes were observed from yellow to red and orange with a limit of detection (LOD) of 1.66×10(-6)mol. L(-1) and 1.24×10(-6)mol. L(-1) at room temperature, respectively. The chemosensor showed visual changes towards cations, such as Al(3+), Cu(2+), Fe(3+), and Cr(3+), in DMSO/water (9:1). The detection limit of receptor L for the analysis of Al(3+) ion was calculated to be 3.02×10(-6)mol. L(-1). The anion recognition property of the receptor via proton transfer was monitored by UV-visible titration and (1)HNMR spectroscopy. The binding constant (Ka) and stoichiometry of the host-guest complexes formed were determined by the Benesi-Hildebrand (B-H) plot and Job's method, respectively. PMID:27474311

  7. Synthesis and characterisation of nitrogen poly-heterocyclic molecules using as selective complexing agents of metallic cations; Synthese et caracterisation de molecules polyheterocycliques azotees utilisables en tant que complexants selectifs de cations metalliques

    Energy Technology Data Exchange (ETDEWEB)

    Alphonse, F.A

    2003-12-15

    Separation of actinides (III) from lanthanides (III) is a crucial problem in the reprocessing of used nuclear fuels. Experimental results shown that soft donor extractants such as nitrogen polydentate heterocycles containing a NCCNCCN coordination site are potentials ligands for selective extraction of actinides (III). In those cases, two types of liquid-liquid extractions are employed: synergistic combination with lipophilic acid extractants and direct extraction. On the basis of the Hard and Soft Acids and Bases theory and basicity evaluation, new extractants were defined. We have first studied the synthesis of potential 1,3,5-triazine ligands designed for extraction in synergy with {alpha}-bromodecanoic acid. Secondly, we have examined the synthesis of bis-triazinyl-pyridine ligands for direct extraction studies. Extraction tests were carried out and perspectives of synthesis were deducted from those extraction results. (author)

  8. Liquid-solid extraction of metallic cations by cationic amphiphiles

    International Nuclear Information System (INIS)

    In the field of selective metal ion separation, liquid-liquid extraction is usually conducted through an emulsion mixing of hydrophobic complexants dispersed in an organic phase and acidic water containing the ionic species. Recently, it has been shown that amphiphilic complexants could influence strongly extraction efficiency by enhancing the interfacial interaction between the metal ion in the aqueous and the complexant in the organic phase. Moreover, these amphiphiles can also substitute the organic phase if an appropriate aliphatic chain is chosen. The dispersion of such amphiphilic complexants in an aqueous solution of salt mixtures is not only attractive for studying specific interactions but also to better the understanding of complex formation in aqueous solution of multivalent metal ions, such as lanthanides and actinides. This understanding is of potential interest for a broad range of industries including purification of rare earth metals and pollute treatment e.g. of fission byproducts. This principle can also be applied to liquid-solid extraction, where the final state of the separation is a solid phase containing the selectively extracted ions. Indeed, a novel solid-liquid extraction method exploits the selective precipitation of metal ions from an aqueous salt mixture using a cationic surfactant, below its Krafft point (temperature below which the long aliphatic chains of surfactant crystallize). This technique has been proven to be highly efficient for the separation of actinides and heavy metal using long chain ammonium or pyridinium amphiphiles. The most important point in this process is the recognition of cationic metal ions by cationic surfactants. By computing the free energy of the polar head group per micelle as a function of the different counter-anions, we have demonstrated for the first time that different interactions exist between the micellar surface and the ions. These interactions depend on the nature of the cation but also on

  9. Radionuclide Incorporation in Secondary Crystalline Minerals Resulting from Chemical Weathering of Selected Waste Glasses: Progress Report: Task kd.5b

    Energy Technology Data Exchange (ETDEWEB)

    Mattigod, Shas V.; Serne, R. Jeffrey; Legore, Virginia L.; Parker, Kent E.; Orr, Robert D.; McCready, David E.; Young, James S.

    2003-09-29

    Experiments were conducted by Pacific Northwest National Laboratory to evaluate potential incorporation of radionuclides in secondary mineral phases that form from weathering vitrified nuclear waste glasses. These experiments were conducted as part of the Immobilized Low-Activity Waste-Performance Assessment (ILAW-PA) to generate data on radionuclide mobilization and transport in a near-field environment of disposed vitrified wastes. The results of these experiments demonstrated that radionuclide sequestration can be significantly enhanced by promoting the formation of cage structured minerals such as sodalite from weathering glasses. These results have important implications regarding radionuclide sequestration/mobilization aspects that are not currently accounted for in the ILAW PA. Additional studies are required to confirm the results and to develop an improved understanding of the mechanisms of sequestration of radionuclides into the secondary and tertiary weathering products of the ILAW glass to help refine how contaminants are released from the near-field disposal region out into the accessible environment. Of particular interest is to determine whether the contaminants remain sequestered in the glass weathering products for hundreds to thousands of years. If the sequestration can be shown to continue for long periods, another immobilization process can be added to the PA analysis and predicted risks should be lower than past predictions.

  10. Radionuclide Incorporation in Secondary Crystalline Minerals Resulting from Chemical Weathering of Selected Waste Glasses: Progress Report: Task kd.5b

    International Nuclear Information System (INIS)

    Experiments were conducted by Pacific Northwest National Laboratory to evaluate potential incorporation of radionuclides in secondary mineral phases that form from weathering vitrified nuclear waste glasses. These experiments were conducted as part of the Immobilized Low-Activity Waste-Performance Assessment (ILAW-PA) to generate data on radionuclide mobilization and transport in a near-field environment of disposed vitrified wastes. The results of these experiments demonstrated that radionuclide sequestration can be significantly enhanced by promoting the formation of cage structured minerals such as sodalite from weathering glasses. These results have important implications regarding radionuclide sequestration/mobilization aspects that are not currently accounted for in the ILAW PA. Additional studies are required to confirm the results and to develop an improved understanding of the mechanisms of sequestration of radionuclides into the secondary and tertiary weathering products o f the ILAW glass to help refine how contaminants are released from the near-field disposal region out into the accessible environment. Of particular interest is to determine whether the contaminants remain sequestered in the glass weathering products for hundreds to thousands of years. If the sequestration can be shown to continue for long periods, another immobilization process can be added to the PA analysis and predicted risks should be lower than past predictions

  11. Development of a ceramic membrane from a lithian spinel, Li1+xMyMn2-yO4 (M=trivalent or tetravalent cations) for a Li ion-selective electrode

    Science.gov (United States)

    Yoon, H.; Venugopal, N.; Rim, T.; Yang, B.; Chung, K.; Ko, T.

    2010-12-01

    Recently a few lithium containing ceramics are reported as promising cathodes for application in lithium batteries. Among them, a spinel-type lithium manganate (LM) exhibits an exceptionally high ion selectivity at room temperature. Thus, LM could have a great potential as an ion selective membrane material for screening interfering ions from lithium ion for the determination of lithium ion in salt solution. In this study, we developed an ion-selective electrode based on LM as a membrane material and investigated its lithium ion selectivity by varying the content of M in composition. A sol-gel process was successfully applied for preparing LM films without resorting to calcination at a high temperature. The LM thin film-type membranes exhibit a high selectivity for Li ion over other cations, a wide operation detection range of 10-5 ~ 10-2 M, and a fast response time less than 60 s. Furthermore, our result demonstrates a linear potentiometric response over a wide range of lithium concentration, which is compared to that of a lithium ion-selective electrode based on an ionophore. Acknowledgements: This research was supported by a grant from the Development of Technology for Extraction of Resources Dissolved in Sea Water Program funded by Ministry of Land Transport and Maritime Affairs in Korean Government (2010).

  12. Cobalt bis(dicarbollide) ions with covalently bonded CMPO groups as selective extraction agents for lanthanide and actinide cations from highly acidic nuclear waste solutions

    International Nuclear Information System (INIS)

    A new series of boron substituted cobalt bis(dicarbollide)(1-) ion (1) derivatives of the general formula [(8-CMPO-(CH2-CH2O)2-1,2-C2B9H10)(1',2'-C2B9H11)-3,3'-Co]- (CMPO = Ph2P(O)-CH2C(O)NR, R = C4H9 (3b), -C12H25 (4b), -CH2-C6H5 (5b)) was prepared by ring cleavage of the 8-dioxane-cobalt bis(dicarbollide) (2) bi-polar compound by the respective primary amines and by subsequent reaction of the resulting amino derivatives (3a-5a) with the nitrophenyl ester of diphenyl-phosphoryl-acetic acid. The compounds were synthesized with the aim to develop a new class of more efficient extraction agents for liquid/liquid extraction of polyvalent cations, i.e. lanthanides and actinides, from high-level activity nuclear waste. All compounds were characterized by a combination of 11B NMR, 1H high field NMR, Mass Spectrometry with Electro-spray and MALDI TOF ionisation, HPLC and other techniques. The molecular structure of the supramolecular Ln3+ complex of the anion 5b was determined by single crystal X-ray diffraction analysis. Crystallographic results proved that the Ln(m) atom is bonded to three functionalized cobalt bis(dicarbollide) anions in a charge compensated complex. The cation is tightly coordinated by six oxygen atoms of the CMPO terminal groups (two of each ligand) and by three water molecules completing the metal coordination number to 9. Atoms occupying the primary coordination sphere form a tri-capped trigonal prismatic arrangement. Very high liquid-liquid extraction efficiency of all anionic species was observed. Moreover, less polar toluene can be applied as an auxiliary solvent replacing the less environmentally friendly nitro- and chlorinated solvents used in the current dicarbollide liquid-liquid extraction process. The extraction coefficients are sufficiently high for possible technological applications. (authors)

  13. Novel phosphate glasses for bone regeneration applications

    OpenAIRE

    Burling, Luke Donald

    2006-01-01

    Phosphate glass with additions of sodium, magnesium and/or calcium were investigated for their potential to be used as the reinforcing phase in a completely degradable long fibre composite. Glasses were prepared from phosphate salts as opposed to oxides and melted under air in platinum/gold crucibles. The effect of cation addition on the material properties and biocompatibility was investigated. Glasses were characterised using a number of complimentary techniques, including: XRD, XPS, DSC...

  14. A combined experimental and quantum mechanical investigation on some selected metal complexes of L-serine with first row transition metal cations

    Science.gov (United States)

    Mandal, Shilpi; Das, Gunajyoti; Askari, Hassan

    2015-02-01

    In the current study a joint solvent-free synthetic and computational approach has been adopted to explore the coordination properties of L-serine with the doubly charged cations of nickel, copper and zinc. The reaction products were characterized by elemental analyses, molar conductance, EDAX-SEM, TEM, TG/DTA, infrared, electronic absorption and fluorescence spectroscopy. Quantum chemical calculations, carried out in gas and aqueous phase using the BHandHLYP and MP2 methods in conjunction with 6-311++G(d,p) basis set, provide valuable insights concerning the interaction enthalpies and free energies; vibrational and absorption spectra along with various other molecular and electronic properties of the metal complexes. This study reveals that L-serine binds to the metal ions in a bi-dentate manner through its amino and carboxylate groups exhibiting highest binding affinity towards Cu(II) among the three metal ions considered here. As compared to the MP2 method, the spin-delocalized situations of the open-shell Cu(II) complex of L-serine have been better described at the BHandHLYP level. The physical origin of the molecular interactions of L-serine with the metal ions has also been examined by performing energy decomposition analysis (EDA). Effects of the aqueous environment are evident on the structure and stability of the metal complexes. The vibrational spectroscopic data furnished at MP2/6-311++G(d,p) level, which provide a good account of the structural changes inflicted in the molecular geometry of L-serine as a result of metal coordination, are in better agreement with our experimental observations as compared to those produced at the BHandHLYP/6-311++G(d,p) level.

  15. Boosted selective internal radiation therapy with 90Y-loaded glass microspheres (B-SIRT) for hepatocellular carcinoma patients: a new personalized promising concept

    International Nuclear Information System (INIS)

    To evaluate the impact of dosimetry based on MAA SPECT/CT for the prediction of response, toxicity and survival, and for treatment planning in patients with hepatocellular carcinoma (HCC) treated with 90Y-loaded glass microspheres (TheraSphere registered). TheraSphere registered was administered to 71 patients with inoperable HCC. MAA SPECT/CT quantitative analysis was used for the calculation of the tumour dose (TD), healthy injected liver dose (HILD), and total injected liver dose. Response was evaluated at 3 months using EASL criteria. Time to progression (TTP) and overall survival (OS) were evaluated using the Kaplan-Meier method. Factors potentially associated with liver toxicity were combined to construct a liver toxicity score (LTS). The response rate was 78.8 %. Median TD were 342 Gy for responding lesions and 191 Gy for nonresponding lesions (p 205 Gy (p = 0.0015 and not significant). Among patients with portal vein thrombosis (PVT) (n = 33), the median TTP and OS were 4.5 months (2-7 months) and 5 months (2-8 months), respectively, in patients with TD 205 Gy (p = 0.039 and 0.005). The median OS was 24.5 months (18-28.5 months) in PVT patients with TD >205 Gy and good PVT targeting on MAA SPECT/CT. The LTS was able to detect severe liver toxicity (n = 6) with a sensitivity of 83 % and overall accuracy of 97 %. Dosimetry based on MAA SPECT/CT was able to accurately predict response and survival in patients treated with glass microspheres. This method can be used to adapt the injected activity without increasing liver toxicity, thus defining a new concept of boosted selective internal radiation therapy (B-SIRT). This new concept and LTS enable fully personalized treatment planning with glass microspheres to be achieved. (orig.)

  16. Nickel-assisted growth and selective doping of spinel-like gallium oxide nanocrystals in germano-silicate glasses for infrared broadband light emission

    International Nuclear Information System (INIS)

    The target of taking advantage of the near-infrared light-emission properties of nickel ions in crystals for the design of novel broadband optical amplifiers requires the identification of suitable nanostructured glasses able to embed Ni-doped nanocrystals and to preserve the workability of a glass. Here we show that Ni doping of Li2O–Na2O–Ga2O3–GeO2–SiO2 glass (with composition 7.5:2.5:20:35:35 and melting temperature 1480 °C, sensibly lower than in Ge-free silicates) enables the selective embedding of nickel ions in thermally grown nanocrystals of spinel-like gallium oxide. The analysis of transmission electron microscopy and x-ray diffraction data as a function of Ni-content (from 0.01 to 1 mol%) indicates that Ni ions promote the nanophase crystallization without affecting nanoparticle size (∼6 nm) and concentration (∼4 × 1018 cm−3). Importantly, as shown by optical absorption spectra, all nickel ions enter into the nanophase, with a number of ions per nanocrystal that depends on the nanocrystal concentration and ranges from 1 to 102. Photoluminescence data indicate that fast non-radiative decay processes become relevant only at mean ion–ion distances shorter than 1.4 nm, which enables the incorporation of a few Ni ions per nanoparticle without too large a worsening of the light-emission efficiency. Indeed, at 0.1 mol% nickel, the room temperature quantum yield is 9%, with an effective bandwidth of 320 nm.

  17. Cation-cation interaction in neptunyl(V) compounds

    International Nuclear Information System (INIS)

    The original manuscript was prepared by Professor N.N. Krot of Institute of Physical Chemistry, Russian Academy of Sciences, in 1997. Saeki tried to translate that into Japanese and to add some new data since 1997. The contents include the whole picture of cation-cation interactions mainly in 5-valence neptunium compounds. Firstly, characteristic structures of neptunium are summarized of the cation-cation bonding in compounds. Secondly, it is mentioned how the cation-cation bonding affects physical and chemical properties of the compounds. Then, characterization-methods for the cation-cation bonding in the compounds are discussed. Finally, the cation-cation interactions in compounds of other actinide-ions are shortly reviewed. (author)

  18. Single-pass continuous-flow leach test of PNL 76-68 glass: some selected Bead Leach I results

    International Nuclear Information System (INIS)

    A single-pass continuous-flow leach test of PNL 76-68 glass beads (7 mm dia) was concluded after 420 days of uninterrupted operation. Variables included in the experimental matrix were flow-rate, leachant composition, and temperature. Analysis was conducted on all leachate samples for 237Np and 239Pu as well as a number of nonradioactive elements. Results indicated that flow-rate and leachant systematically affected the leach rate, but only slightly. Temperature effects were significant. Plutonium leach rate was lower at higher temperature suggesting that Pu sorption onto the beads was enhanced at the higher temperature. The range of leach rates for all analyzed elements (except Pu), at both temperatures, at all three flow rates, and with all three leachant compositions varied over only three orders of magnitude. The range of variables used in this experiment covered those expected in many proposed repository environments. The preliminary interpretation of the results aPPh3 also reacted with Mn2(CO)10 and Cp2Mo2(CO)6 to give a variety of products at room temperature. A radical mechanism was suggested

  19. Bespoke cationic nano-objects via RAFT aqueous dispersion polymerisation

    OpenAIRE

    Williams, M.; Penfold, NJW; Lovett, JR; Warren, NJ; Douglas, CWI; Doroshenko, N; Verstraete, P; Smets, J; Armes, SP

    2016-01-01

    A range of cationic diblock copolymer nanoparticles are synthesised via polymerisation-induced self-assembly (PISA) using a RAFT aqueous dispersion polymerisation formulation. The cationic character of these nanoparticles can be systematically varied by utilising a binary mixture of two macro-CTAs, namely non-ionic poly(glycerol monomethacrylate) (PGMA) and cationic poly[2-(methacryloyloxy)ethyl]trimethylammonium chloride (PQDMA), with poly(2-hydroxypropyl methacrylate) (PHPMA) being selected...

  20. Baeyer-Villiger oxidation of cyclic ketones with hydrogen peroxide catalyzed by cationic complexes of platinum(II): Selectivity properties and mechanistic studies

    Energy Technology Data Exchange (ETDEWEB)

    Del Todesco Frisone, M.; Pinna, F.; Strukul, G. (Univ. of Venice (Italy))

    1993-01-01

    The catalytic oxidation of simple cyclic ketones with hydrogen peroxide to give the corresponding lactones is reported. The reaction is catalyzed by complexes of Pt(II) of the type [(P-P)Pt(CF[sub 3])(solv)][sup +] (P-P = diphosphine) that may be deactivated by the hydroxy acids formed by hydrolysis of the lactones. The selectivity of the catalyst is studied in the oxidation of substrates like camphor, 2-cyclohexene-1-one, menthone, carvone, and indanones. Cyclobutanone is used to determine the mechanism of the reaction from initial rates studies. The reaction scheme proposed, which accounts for the observed effects of the various reactants, involves the coordination of the ketone on the vacant coordination site of the complex followed by nucleophilic attack of free hydrogen peroxide on the carbonyl carbon. The involvement of a quasi-peroxymetallacyclic intermediate is suggested which rearranges to give the lactone and the starting complex. A comparison with the mechanistic behavior of organic peroxy acids is given. 24 refs., 10 figs., 3 tabs.

  1. Cation locations and dislocations in zeolites

    Science.gov (United States)

    Smith, Luis James

    The focus of this dissertation is the extra-framework cation sites in a particular structural family of zeolites, chabazite. Cation sites play a particularly important role in the application of these sieves for ion exchange, gas separation, catalysis, and, when the cation is a proton, acid catalysis. Structural characterization is commonly performed through the use of powder diffraction and Rietveld analysis of powder diffraction data. Use of high-resolution nuclear magnetic resonance, in the study of the local order of the various constituent nuclei of zeolites, complements well the long-range order information produced by diffraction. Recent developments in solid state NMR techniques allow for increased study of disorder in zeolites particularly when such phenomena test the detection limits of diffraction. These two powerful characterization techniques, powder diffraction and NMR, offer many insights into the complex interaction of cations with the zeolite framework. The acids site locations in SSZ-13, a high silica chabazite, and SAPO-34, a silicoaluminophosphate with the chabazite structure, were determined. The structure of SAPO-34 upon selective hydration was also determined. The insensitivity of X-rays to hydrogen was avoided through deuteration of the acid zeolites and neutron powder diffraction methods. Protons at inequivalent positions were found to have different acid strengths in both SSZ-13 and SAPO-34. Other light elements are incorporated into zeolites in the form of extra-framework cations, among these are lithium, sodium, and calcium. Not amenable by X-ray powder diffraction methods, the positions of such light cations in fully ion-exchanged versions of synthetic chabazite were determined through neutron powder diffraction methods. The study of more complex binary cation systems were conducted. Powder diffraction and solid state NMR methods (MAS, MQMAS) were used to examine cation site preferences and dislocations in these mixed-akali chabazites

  2. Boosted selective internal radiation therapy with {sup 90}Y-loaded glass microspheres (B-SIRT) for hepatocellular carcinoma patients: a new personalized promising concept

    Energy Technology Data Exchange (ETDEWEB)

    Garin, E.; Lenoir, L. [Comprehensive Cancer Center, Institute Eugene Marquis, Department of Nuclear Medicine, CS 44229, Rennes (France); University of Rennes 1, Rennes (France); INSERM, U-991, Liver Metabolisms and Cancer, Rennes (France); Edeline, J. [University of Rennes 1, Rennes (France); Comprehensive Cancer Center, Institute Eugene Marquis, Department of Medical Oncology, CS 44229, Rennes (France); Laffont, S. [Comprehensive Cancer Center, Institute Eugene Marquis, Department of Nuclear Medicine, CS 44229, Rennes (France); Mesbah, H.; Poree, P. [Comprehensive Cancer Center, Institute Eugene Marquis, Department of Medical Informatics, CS 44229, Rennes (France); Sulpice, L. [INSERM, U-991, Liver Metabolisms and Cancer, Rennes (France); Centre Hospitalier Universitaire Pontchaillou, Department of Digestive Surgery, Rennes (France); Boudjema, K. [University of Rennes 1, Rennes (France); INSERM, U-991, Liver Metabolisms and Cancer, Rennes (France); Centre Hospitalier Universitaire Pontchaillou, Department of Digestive Surgery, Rennes (France); Mesbah, M. [University of Pierre et Marie Curie, Paris (France); Guillygomarc' h, A. [Centre Hospitalier Universitaire Pontchaillou, Department of Hepatology, Rennes (France); Quehen, E. [Centre Hospitalier Universitaire Pontchaillou, Department of Radiology, Rennes (France); Pracht, M. [Comprehensive Cancer Center, Institute Eugene Marquis, Department of Medical Oncology, CS 44229, Rennes (France); Raoul, J.L. [Comprehensive Cancer Center, Institute Paoli Calmette, Department of Medical Oncology, Marseille (France); Clement, B. [INSERM, U-991, Liver Metabolisms and Cancer, Rennes (France); Rolland, Y. [Comprehensive Cancer Center, Institute Eugene Marquis, Department of Medical Imaging, CS 44229, Rennes (France); Boucher, E. [INSERM, U-991, Liver Metabolisms and Cancer, Rennes (France); Comprehensive Cancer Center, Institute Eugene Marquis, Department of Medical Oncology, CS 44229, Rennes (France)

    2013-07-15

    able to accurately predict response and survival in patients treated with glass microspheres. This method can be used to adapt the injected activity without increasing liver toxicity, thus defining a new concept of boosted selective internal radiation therapy (B-SIRT). This new concept and LTS enable fully personalized treatment planning with glass microspheres to be achieved. (orig.)

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

    International Nuclear Information System (INIS)

    ratios is shown to represent the structural effects of the glass on the dissolution and the formation of activated complexes in the glass leached layer. This provides two different methods by which a linear glass durability model can be formulated. One based on the quasi- crystalline mineral species in a glass and one based on cation ratios in the glass: both are related to the activated complexes on the surface by the law of mass action. The former would allow a new Thermodynamic Hydration Energy Model to be developed based on the hydration of the quasi-crystalline mineral species if all the pertinent thermodynamic data were available. Since the pertinent thermodynamic data is not available, the quasi-crystalline mineral species and the activated complexes can be related to cation ratios in the glass by the law of mass action. The cation ratio model can, thus, be used by waste form producers to formulate durable glasses based on fundamental structural and activated complex theories. Moreover, glass durability model based on atomic ratios simplifies HLW glass process control in that the measured ratios of only a few waste components and glass formers can be used to predict complex HLW glass performance with a high degree of accuracy, e.g. an R2 approximately 0.97

  4. An extended topological model for binary phosphate glasses

    DEFF Research Database (Denmark)

    Hermansen, Christian; Rodrigues, B.P.; Wondraczek, L.;

    2014-01-01

    , but for larger ions a significant fraction is broken. By accounting for the fraction of intact modifying ion related constraints, qγ, the Tg(x) of alkali phosphate glasses is predicted. By examining alkali, alkaline earth and rare earth metaphosphate glasses we find that the effective number of intact...... constraints per modifying cation is linearly related to the charge-to-distance ratio of the modifying cation to oxygen....

  5. Surface modification of glass beads with glutaraldehyde: Characterization and their adsorption property for metal ions

    International Nuclear Information System (INIS)

    In this study, a new material that adsorbs the metal ions was prepared by modification of the glass beads surfaces with glutaraldehyde. First, the glass beads were etched with 4 M NaOH solution. Then, they were reacted with 3-aminopropyl-triethoxysilane (APTES). Finally, silanized glass beads were treated with 25% of glutaraldehyde solution. The characterization studies by using Fourier Transform Infrared Spectroscopy (FT-IR), Thermal Gravimetric Analysis (TGA), elemental analysis and Scanning Electron Microscopy (SEM) indicated that modification of the glass bead surfaces was successfully performed. The adsorption studies exhibited that the modified glass beads could be efficiently used for the removal of the metal cations and anion (chromate ion) from aqueous solutions via chelation and ion-exchange mechanisms. For both Pb(II) and Cr(VI), selected as model ions, the adsorption equilibrium was achieved in 60 min and adsorption of both ions followed the second-order kinetic model. It was found that the sorption data was better represented by the Freundlich isotherm in comparison to the Langmuir and Redlich-Peterson isotherm models. The maximum adsorption capacities for Pb(II) and Cr(VI) were 9.947 and 11.571 mg/g, respectively. The regeneration studies also showed that modified glass beads could be re-used for the adsorption of Pb(II) and Cr(VI) from aqueous solutions over three cycles.

  6. Mixed mobile ion effect in fluorozincate glasses

    International Nuclear Information System (INIS)

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

  7. Decontamination glass

    International Nuclear Information System (INIS)

    Glass for the decontamination of the furnace for vitrification of radioactive wastes contains 50 to 60 wt.% of waste glass, 15 to 30 wt.% of calcium oxide, 1 to 6 wt.% sodium oxide, 1 to 5 wt.% phosphorus pentoxide and 5 to 20 wt.% boron oxide. The melting furnace is flushed with the glass such that it melts in the furnace for at least 60 mins and is then poured out of the furnace. After the furnace has cooled down the settled glass spontaneously cracks and peels off the walls leaving a clean surface. The glass may be used not only for decontamination of the furnace but also for decontamination of melting crucibles and other devices contaminated with radioactive glass. (J.B.)

  8. Recycle Glass in Foam Glass Production

    OpenAIRE

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

    2014-01-01

    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.

  9. 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....

  10. Low cation coordination in oxide melts

    Energy Technology Data Exchange (ETDEWEB)

    Skinner, Lawrie [State University of New York, Stony Brook; Benmore, Chris J [Argonne National Laboratory (ANL); Du, Jincheng [University of North Texas; Weber, Richard [Argonne National Laboratory (ANL); Neuefeind, Joerg C [ORNL; Tumber, Sonia [Materials Development, Inc., Evanston, IL; Parise, John B [Stony Brook University (SUNY)

    2014-01-01

    The complete set of Faber-Ziman partial pair distribution functions for a rare earth oxide liquid were measured for the first time by combining aerodynamic levitation, neutron diffraction, high energy x-ray diffraction and isomorphic substitution using Y2 O3 and Ho2 O3 melts. The average Y- O coordination is measured to be 5.5(2), which is significantly less than the octahedral coordination of crystalline Y2 O3 (or Ho2 O3 ). Investigation of high temperature La2 O3 , ZrO2 , SiO2 , and Al2 O3 melts by x-ray diffraction and molecular dynamics simulations also show lower-than-crystal cation- oxygen coordination. These measurements suggest a general trend towards lower M-O coordination compared to their crystalline counterparts. It is found that this coordination number drop is larger for lower field strength, larger radius cations and is negligible for high field strength (network forming) cations. These findings have broad implications for predicting the local structure and related physical properties of metal-oxide melts and oxide glasses.

  11. Selective laser melting of an Al86Ni6Y4.5Co2La1.5 metallic glass: Processing, microstructure evolution and mechanical properties

    International Nuclear Information System (INIS)

    In this study, single line scans at different laser powers were carried out using selective laser meting (SLM) equipment on a pre-fabricated porous Al86Ni6Y4.5Co2La1.5 metallic glass (MG) preform. The densification, microstructural evolution, phase transformation and mechanical properties of the scan tracks were systematically investigated. It was found that the morphology of the scan track was influenced by the energy distribution of the laser beam and the heat transfer competition between convection and conduction in the melt pool. Due to the Gaussian distribution of laser energy and heat transfer process, different regions of the scan track experienced different thermal histories, resulting in a gradient microstructure and mechanical properties. Higher laser powers caused higher thermal stresses, which led to the formation of cracks; while low power reduced the strength of the laser track, also inducing cracking. The thermal fluctuation at high laser power produced an inhomogeneous chemical distribution which gave rise to severe crystallization of the MG, despite the high cooling rate. The crystallization occurred both within the heat affected zone (HAZ) and at the edge of melt pool. However, by choosing an appropriate laser power crack-free scan tracks could be produced with no crystallization. This work provides the necessary fundamental understanding that will lead to the fabrication of large-size, crack-free MG with high density, controllable microstructure and mechanical properties using SLM

  12. A glass durability model based on understanding glass chemistry and structural configurations of the glass constituents

    International Nuclear Information System (INIS)

    An improved structural bond strength (SBS) model has been developed to quantify the correlation between glass compositions and their chemical durabilities. The SBS model assumes that the strengths of the bonds between cations and oxygens and the structural roles of the individual elements in the glass are the predominant factors controlling the composition dependence of the chemical durability of glasses. The structural roles of oxides in glass are classified as network formers, network breakers, and intermediates. The structural roles of the oxides depend on glass composition and the redox state of oxides. Al2O3, ZrO2, Fe2O3, and B2O are assigned as network formers only when there are sufficient alkalis to bind with these oxides CaO can also improve durability by sharing non-bridging oxygen with alkalis, relieving SiO2 from alkalis. The binding order to alkalis is Al2O3 > ZrO2 > Fe2O3 > B2O3 > CaO > SiO2. The percolation phenomenon in glass is also taken into account. The concentration of network formers as to reach a critical value for a glass to become durable; durable glasses are sufficient in network formers and have a complete network structure; poor durability glasses are deficient in network formers and the network is incomplete and discontinuous. The SBS model is capable of correlating the 7-day product consistency test durability of 42 low-level waste glasses with their composition with an R2 of 0.87, which is better than 0.81 obtained with an eight-coefficient empirical first-order mixture model on the same data

  13. {sup 1}H and {sup 23}Na MAS NMR spectroscopy of cationic species in CO{sub 2} selective alkaline earth metal porous silicoaluminophosphates prepared via liquid and solid state ion exchange

    Energy Technology Data Exchange (ETDEWEB)

    Arevalo-Hidalgo, Ana G. [Department of Chemical Engineering, University of Puerto Rico-Mayagueez Campus, Mayagueez, PR 00681-9000 (Puerto Rico); Dugar, Sneha; Fu, Riqiang [National High Magnetic Field Laboratory, Florida State University, Tallahassee, FL 32310 (United States); Hernandez-Maldonado, Arturo J., E-mail: arturoj.hernandez@upr.edu [Department of Chemical Engineering, University of Puerto Rico-Mayagueez Campus, Mayagueez, PR 00681-9000 (Puerto Rico)

    2012-07-15

    The location of extraframework cations in Sr{sup 2+} and Ba{sup 2+} ion-exchanged SAPO-34 was estimated by means of {sup 1}H and {sup 23}Na MAS NMR spectroscopy and spectral deconvolution. Incorporation of the alkaline earth metal cations onto the SAPO framework was achieved via liquid state ion exchange, coupled partial detemplation/solid-state ion exchange, and combination of both techniques. MAS NMR revealed that the level of ion exchange was limited by the presence of protons and sodium cations near hexagonal prisms (site SI), which are relatively difficult to exchange with the alkaline earth metal due to steric and charge repulsion criteria. In addition, the presence of ammonium cations in the supercages facilitated the exchange of otherwise tenacious hydrogen as corroborated by unit cell compositional data as well as enhanced CO{sub 2} adsorption at low partial pressures. The extraframework ammonium species were produced from partial detemplation of the structure-directing agent employed for the SAPO-34 synthesis, tetraethylammonium. - Graphical abstract: MAS NMR was used to elucidate the position the cationic species in alkaline earth metal exchanged silicoaluminophosphates. These species played a significant role during the ion exchange process and, therefore, the materials ultimate CO{sub 2} adsorption performance. Highlights: Black-Right-Pointing-Pointer Location of extraframework Sr{sup 2+} or Ba{sup 2+} cations was estimated by means of {sup 1}H and {sup 23}Na MAS NMR. Black-Right-Pointing-Pointer Level of Sr{sup 2+} or Ba{sup 2+} ion exchange was limited by the presence of protons and sodium cations. Black-Right-Pointing-Pointer Presence of ammonium cations in the supercages facilitated the exchange. Black-Right-Pointing-Pointer Sr{sup 2+} and Ba{sup 2+} ion exchanged SAPOs are outstanding CO{sub 2} adsorbents.

  14. Site selection using laser-induced fluorescence spectroscopy of the Eu3+ probe ions in oxide glass hosts: a review and some new results

    International Nuclear Information System (INIS)

    The laser-induced fluorescence line narrowing method, using the optical properties of Eu3+-doped oxide glasses, has been used to investigate the local structure and structural inhomogeneities of glasses. Recent contributions are reviewed which indicate the present state of knowledge and new results obtained for these materials, which show a discrete site distribution instead of the usual site continuum, are reported. (Auth.)

  15. 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....

  16. 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....

  17. 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.

  18. Cationic Antimicrobial Peptide Cytotoxicity

    OpenAIRE

    Laverty, Garry; Gilmore, Brendan

    2014-01-01

    Fluorescence microscopy serves as a valuable tool for assessing the structural integrity and viability of eukaryotic cells. Through the use of calcein AM and the DNA stain 4,6-diamidino-2 phenylindole (DAPI), cell viability and membrane integrity can be qualified. Our group has previously shown the ultra-short cationic antimicrobial peptide H-OOWW-NH2; the amphibian derived 27-mer peptide Maximin-4and the ultra-short lipopeptide C12-OOWW-NH2 to be effective against a range of bacterial biofil...

  19. Photonic glasses

    CERN Document Server

    Gan, Fuxi

    2006-01-01

    This book introduces the fundamental mechanism of photonic glasses - the linear and nonlinear optical effects in glass under intense light irradiation: phot-induced absorption, refraction, polarization, frequency, coherence and monochromaticity changes. Emphasis is placed on new developments in the structure, spectroscopy and physics of new glassy materials for photonics applications, such as optical communication, optical data storage, new lasers and new photonic components and devices. The book presents the research results of the authors in new glasses for photonics over the last decade. Sa

  20. Joule-heated glass-furnace system for the incineration of low-level radioactive wastes

    International Nuclear Information System (INIS)

    For the past 1-1/2 years, Mound has been preparing and evaluating a commercially available joule-heated glass furnace unit, coupled with a wet scrubbing system. The purpose of the glass furnace evaluation is to advance and document incinerator technology for such combustibles as solids, resins, and sludges, and to develop a stable waste form for subsequent disposal. Four (4) waste nonradioactive types were selected to determine the combustion efficiency of the furnace unit: (1) dry solid waste composed of paper, plastics, rubber, and cloth, (2) ion exchange resin of both the anionic and cationic type, (3) filter sludge composed of diatomaceous earth, organic cellulosic filter aid, and powdered ion exchange resin, and (4) cartridge filters having glass and plastic filter surfaces and nonmetallic cores. When completed, the combustion efficiency experiments for the proposed nonradioactive waste-types revealed the ability of the furnace to easily incinerate waste at feedrates of up to 150 lb/hr. During the course of the experiments, combustibles in the offgas remained consistently low, suggesting excellent combustion efficiency. Furthermore, ash produced by the combustion process was effectively incorporated into the melt by convective currents in the glass. Future work on the glass furnace incinerator will include spiking the waste to determine radioisotope behavior in the furnace

  1. Effect of water glass modification with nanoparticles of zinc oxide on selected physical and chemical properties of binder and mechanical properties of sand mixture

    Directory of Open Access Journals (Sweden)

    A. Kmita

    2012-12-01

    Full Text Available In this paper, an attempt was made to use the ZnO nanoparticles as a modifier of foundry binder - water glass. The modifier was a colloidal suspension of the ZnO zinc oxide nanoparticles in propanol. A thermal method to obtain metal oxide nanoparticles was adopted. The modifier was product of the thermal decomposition of the basic zinc carbonate ([ZnCO3]2•[Zn(OH2]3, and was introduced into the water glass in an amount of 1 and 3 wt%. To determine the interfacial reactions taking place in a quartz - modified water glass system, the binder wettability of the quartz grains was measured. The effect of water glass modification on the mechanical properties of moulding sands was verified by testing the tensile strength Rm u of moulding sands with the modified binders. Water glass modification with the colloidal solution of ZnO nanoparticles in propanol confirmed the effect of modifier on the water glass wettability of sand grains and on the mechanical properties of the sand mixtures with this additive.

  2. Cation exchange applications of synthetic tobermorite for the immobilization and solidification of cesium and strontium in cement matrix

    Indian Academy of Sciences (India)

    O P Shrivastava; Rashmi Shrivastava

    2000-12-01

    Immobilization and solidification of hazardous cations like Cs137 and Sr90 are required while handling the radioactive waste of nuclear power plants. Efforts are on to find a fail proof method of safe disposal of nuclear wastes. In this context, various materials like borosilicate glass, zeolites, cements and synthetic rocks have been tried by several workers. This communication deals with the synthesis, characterization, cesium uptake capacity and leaching behaviour of synthetic alumina-substituted calcium silicate hydroxy hydrate, which are close to that obtained for the natural mineral, 11 Å tobermorite. The synthetic mineral show cation selectivity for Cs+ in presence of 500–1000 times concentrated solutions of Na+ , K+ , Mg2+, Ca2+ , Ba2+ and Sr2+. Although the ordinary portland cement (OPC) which is often used in waste management operations alone holds negligible amounts of Cs+ and Sr2+, the addition of alumina-substituted tobermorite to OPC enhances the retention power of cement matrix by drastically lowering the leach rate of cations.

  3. Fixation by ion exchange of toxic materials in a glass matrix

    International Nuclear Information System (INIS)

    A process is reported for reacting a porous silicate or borosilicate glass or silica gel with alkali metal cations, Group lb cations and/or ammonium cations bonded to the silicon through divalent oxygen linkages on the internal surfaces of the pores. Ion exchange of the cations with toxic or radioactive cations was possible resulting in a distribution of internal silicon-bonded toxic cation oxide groups within the pores of the glass or silica gel. The ion exchange reaction may be done successfully with acidic, neutral or alkaline pH solutions. The aim of the immobilization is for permanent storage of hazardous materials such as Hg2+, Hg+, Cd2+, Tl+, Pb2+ and radioactive cations

  4. Booted selective internal radiation therapy (B-SIRT) using 90Y-loaded glass microspheres induces prolonged overall survival for PVT patients

    International Nuclear Information System (INIS)

    Full text of publication follows. Goal: evaluation of the response rate and survival of hepatocellular carcinoma PVT patients treated with Therasphere using the boost concept. Material and methods: Therasphere was administered in 40 PVT hepatocellular carcinoma patients (main = 11, lobar = 23, segmental = 6). MAA SPECT/CT quantitative analysis was used for the calculation of the tumour dose (TD), the healthy injected liver dose (HLD) and the injected liver dose (LD). Response was evaluated at 3 months using EASL criterion. OS was evaluated using Kaplan and Meyer tests. Results: Mean 90Y-loaded microspheres injected activity was 3.1 ± 1.5 GBq. Mean LD was 143 ± 49 Gy. Median TD was 316 Gy for responding lesions versus 133 Gy for non responding lesion (p<0.0001). With a threshold TD of 205 Gy, MAA-SPECT/CT was predictive of response with a sensibility of 100%, and an overall accuracy of 90% (0FN, 4FP). Knowing the TD and the HLD, 40% of the patients received an intensification of the treatment (increase of the injected activity with the goal to achieve a TD> 205 Gy with a LD > 150 Gy and a HLD<120 Gy) with a good response rate (81%) and without increased liver grade III toxicity (6.2% as against 12.5% in the non boosted patients, ns). 6 patients were put aside, 5 received a lobar hepatectomy. Median OS was 18.2 months [12-27]. It was 4 m [12-27] for patients with a TD < 205 Gy versus 21.5 m [12-28.5] for patients with a TD > 205 Gy. OS was 12 m [3-∞] for patients with main PVT versus 21.5 m [12-28.7] for patients segmental or lobar PVT (ns). Finally Os was 23.2 m for patients with a TD > 205 Gy and a good PVT targeting (n = 34). Conclusion: boosted selective internal radiation therapy using 90Y-loaded glass microspheres induces prolonged overall survival for PVT patients without increasing liver toxicity. (authors)

  5. Ion exchange behaviour of polymeric zirconium cations

    International Nuclear Information System (INIS)

    Polymeric zirconium cations formed in weakly acid solutions (pH2) are taken up strongly into macroporous cation exchange resins, while uptake into normal cation exchange resins (pore diameter about 1 nm) is low. Macroporous cation exchange resins loaded with polymeric Zr cations are shown to function as ligand exchange sorbents. (Authors)

  6. Differential modulation by cations of sigma and phencyclidine binding sites in rat brain

    International Nuclear Information System (INIS)

    The present investigation attempted to differentiate haloperidol-sensitive sigma sites (sigma H) from phencyclidine (PCP) binding sites in rat brain membranes. We studied the effects of several cations at physiologically relevant concentrations on the binding of radioligands selective for sigma H sites ([3H]haloperidol, [3H](+)3-PPP**), and [3H](+)SKF10,047, or for PCP sites ([3H]PCP and [3H]TCP). The PCP sites displayed a markedly greater sensitivity to cations than sigma H sites. This property was reflected by a greater extent of inhibition of the binding of PCP-selective relative to sigma H-selective ligands at a given cation concentration, as well as by lower IC50's and by steeper slopes of the cation dose-response curves. Divalent cations were approximately 100 times more potent than monovalent cations. All cations were inhibitory, except Sr2+ and Ba2+ which, at micromolar concentrations, enhanced PCP binding but not sigma H binding. Thus, PCP-selective sites appeared to be distinct from sigma H sites with regards to several aspects of cation modulation. This is consistent with the view that PCP and sigma H sites are distinct molecular entities. Further, the marked cation sensitivity of the PCP site is consistent with the current hypothesis according to which the PCP site is linked to the N-methyl-D-aspartate (NMDA) receptor-cation channel complex

  7. Characterisation of ion transport in sulfonate based ionomer systems containing lithium and quaternary ammonium cations

    International Nuclear Information System (INIS)

    Two sulfonated ionomers based on poly(triethylmethyl ammonium 2-acrylamido-2-methyl-1-propane sulfonic acid) (PAMPS) and containing mixtures of Li+ and quaternary ammonium cations are characterised. The first system contains Li+ and the methyltriethyl ammonium cation (N1222) in a 1:9 molar ratio, and the 7Li NMR line widths showed that the Li+ ions are mobile in this system below the glass transition temperature (105 °C) and are therefore decoupled from the polymer segmental motion. The conductivity in this system was measured as 10−5 S cm−1 at 130 °C. A second PAMPS system containing Li+ and the dimethylbutylmethoxyethyl ammonium cation (N114(2O1)) in a 2:8 molar ratio showed much lower conductivities despite a significantly lower Tg (60 °C), possibly due to associations between the Li+ and the ether group on the ammonium cation, or between the latter cations and the sulfonate groups

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

    International Nuclear Information System (INIS)

    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% Cs2O in IPG; while, breakdown of the phosphate network with increasing cesium content, brings down the glass transition temperature.

  9. Comparison of selected optical properties of oxyfluoride glass fibers doped with Er3+ and co-doped with Er3+ Yb3+

    Science.gov (United States)

    Augustyn, E.; Stremplewski, P.; Rozanski, M.; Koepke, C.; Dominiak-Dzik, G.; Kępińska, M.; Żelechower, M.

    2011-12-01

    The method of manufacturing and spectroscopic evaluation of the Er3+ ions doped and Er3+-Yb3+co-doped SiO2-Al2O3-Na2CO3-CaO-PbO-PbF2 oxyfluoride glass fibers is presented in the paper. Both optically active elements erbium and ytterbium were introduced into the batch in the form of fluorides. The X-ray diffraction (XRD) technique was applied at each stage of fibers manufacturing in order to control an amorphous structure of the preforms and fibers. Optical studies of glass preforms and fibers (reflection/transmission, absorption, emission, and excited state absorption (ESA)) were directed to examine their suitability as fiber amplifiers at 1.55 μm band.

  10. Wear of MgO-CaO-SiO2-P2O5-F-Based Glass Ceramics Compared to Selected Dental Ceramics

    Directory of Open Access Journals (Sweden)

    Abdullah Ozturk

    2007-12-01

    Full Text Available Wear of a glass-ceramic produced through controlled crystallization of a glass in the MgO-CaO-SiO2-P2O5-F system has been evaluated and compared to various commercial dental ceramics including IPS Empress 2, Cergo Pressable Ceramic, Cerco Ceram, and Super porcelain EX-3. Wear tests were performed in accord with the ASTM G99 for wear testing with a pin-on-disk apparatus. The friction coefficient and specific wear rate of the materials investigated were determined at a load of 10 N and at ambient laboratory conditions. Microhardness of the materials was also measured to elucidate the appropriateness of these materials for dental applications.

  11. HEAT CAPACITY AND MEDIUM RANGE ORDER IN OXIDE GLASSES

    OpenAIRE

    Soga, N.

    1982-01-01

    The three-band theory using three characteristic temperatures θE, θ1 and θ3 has been applied to analyze the existing and new data of low temperature heat capacity of various silicates, borates and germanates in both glassy and crystalline states. The values of θE for various modifying cations in glasses were similar to those in crystals. The change in coordination state or short range order of network forming cations was observable in θ1. The values of θ3 for some glasses were considerably sm...

  12. Sintered glass

    International Nuclear Information System (INIS)

    The authors present an overview of various attempts to sinter high-level matrix. This paper focuses on the development of the porous glass matrix process (PGM process) for the fixation of HLW in a high-silica glass matrix by sintering. In the PGM process a borosilicate-type base glass is phase-separated by heat treatment. The low-silica phase is leached in HC1 and washed out. The remaining fine powder is soaked with HLW, dried under vacuum by gradual heating up to 1123 K, ground or ball-milled and finally sintered at 1473 K to a dense solid, consisting of a matrix of 96% SiO2 and 4% B2O3 in which the waste elements are trapped. The main advantage of the process is the high chemical durability of the final product. The rather complicated process technology, also leading to the generation of secondary waste (e.g. washing solution), is considered a disadvantage

  13. Glass packages in interim storage

    International Nuclear Information System (INIS)

    This report summarize the current state of knowledge concerning the behavior of type C waste packages consisting of vitrified high-level solutions produced by reprocessing spent fuel. The composition and the physical and chemical properties of the feed solutions are reviewed, and the vitrification process is described. Sodium alumino-borosilicate glass compositions are generally employed - the glass used at la Hague for LWR fuel solutions, for example, contains 45 % SiO2. The major physical, chemical, mechanical and thermal properties of the glass are reviewed. In order to allow their thermal power to diminish, the 3630 glass packages produced (as of January 1993) in the vitrification facilities at Marcoule and La Hague are placed in interim storage for several decades. The actual interim storage period has not been defined, as it is closely related to the concept and organization selected for the final destination of the packages: a geological repository. The glass behavior under irradiation is described. Considerable basic and applied research has been conducted to assess the aqueous leaching behavior of nuclear containment glass. The effects of various repository parameters (temperature, flow rate, nature of the environmental materials) have been investigated. The experimental findings have been used to specify a model describing the kinetics of aqueous corrosion of the glass. More generally all the ''source term'' models developed in France by the CEA or by ANDRA are summarized. (author). 152 refs., 33 figs

  14. Selective dissolution of halide perovskites as a step towards recycling solar cells

    Science.gov (United States)

    Kim, Byeong Jo; Kim, Dong Hoe; Kwon, Seung Lee; Park, So Yeon; Li, Zhen; Zhu, Kai; Jung, Hyun Suk

    2016-05-01

    Most research on perovskite solar cells has focused on improving power-conversion efficiency and stability. However, if one could refurbish perovskite solar cells, their stability might not be a critical issue. From the perspective of cost effectiveness, if failed, perovskite solar cells could be collected and recycled; reuse of their gold electrodes and transparent conducting glasses could reduce the price per watt of perovskite photovoltaic modules. Herein, we present a simple and effective method for removing the perovskite layer and reusing the mesoporous TiO2-coated transparent conducting glass substrate via selective dissolution. We find that the perovskite layer can be easily decomposed in polar aprotic solvents because of the reaction between polar aprotic solvents and Pb2+ cations. After 10 cycles of recycling, a mesoporous TiO2-coated transparent conducting glass substrate-based perovskite solar cell still shows a constant power-conversion efficiency, thereby demonstrating the possibility of recycling perovskite solar cells.

  15. Selective Dissolution of Halide Perovskites as a Step Towards Recycling Solar Cells

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Byeong Jo; Kim, Dong Hoe; Kwon, Seung Lee; Park, So Yeon; Li, Zhen; Zhu, Kai; Jung, Hyun Suk

    2016-05-23

    Most research on perovskite solar cells has focused on improving power-conversion efficiency and stability. However, if one could refurbish perovskite solar cells, their stability might not be a critical issue. From the perspective of cost effectiveness, if failed, perovskite solar cells could be collected and recycled; reuse of their gold electrodes and transparent conducting glasses could reduce the price per watt of perovskite photovoltaic modules. Herein, we present a simple and effective method for removing the perovskite layer and reusing the mesoporous TiO2-coated transparent conducting glass substrate via selective dissolution. We find that the perovskite layer can be easily decomposed in polar aprotic solvents because of the reaction between polar aprotic solvents and Pb2+ cations. After 10 cycles of recycling, a mesoporous TiO2-coated transparent conducting glass substrate-based perovskite solar cell still shows a constant power-conversion efficiency, thereby demonstrating the possibility of recycling perovskite solar cells.

  16. Selective dissolution of halide perovskites as a step towards recycling solar cells.

    Science.gov (United States)

    Kim, Byeong Jo; Kim, Dong Hoe; Kwon, Seung Lee; Park, So Yeon; Li, Zhen; Zhu, Kai; Jung, Hyun Suk

    2016-01-01

    Most research on perovskite solar cells has focused on improving power-conversion efficiency and stability. However, if one could refurbish perovskite solar cells, their stability might not be a critical issue. From the perspective of cost effectiveness, if failed, perovskite solar cells could be collected and recycled; reuse of their gold electrodes and transparent conducting glasses could reduce the price per watt of perovskite photovoltaic modules. Herein, we present a simple and effective method for removing the perovskite layer and reusing the mesoporous TiO2-coated transparent conducting glass substrate via selective dissolution. We find that the perovskite layer can be easily decomposed in polar aprotic solvents because of the reaction between polar aprotic solvents and Pb(2+) cations. After 10 cycles of recycling, a mesoporous TiO2-coated transparent conducting glass substrate-based perovskite solar cell still shows a constant power-conversion efficiency, thereby demonstrating the possibility of recycling perovskite solar cells. PMID:27211006

  17. Selective dissolution of halide perovskites as a step towards recycling solar cells

    Science.gov (United States)

    Kim, Byeong Jo; Kim, Dong Hoe; Kwon, Seung Lee; Park, So Yeon; Li, Zhen; Zhu, Kai; Jung, Hyun Suk

    2016-01-01

    Most research on perovskite solar cells has focused on improving power-conversion efficiency and stability. However, if one could refurbish perovskite solar cells, their stability might not be a critical issue. From the perspective of cost effectiveness, if failed, perovskite solar cells could be collected and recycled; reuse of their gold electrodes and transparent conducting glasses could reduce the price per watt of perovskite photovoltaic modules. Herein, we present a simple and effective method for removing the perovskite layer and reusing the mesoporous TiO2-coated transparent conducting glass substrate via selective dissolution. We find that the perovskite layer can be easily decomposed in polar aprotic solvents because of the reaction between polar aprotic solvents and Pb2+ cations. After 10 cycles of recycling, a mesoporous TiO2-coated transparent conducting glass substrate-based perovskite solar cell still shows a constant power-conversion efficiency, thereby demonstrating the possibility of recycling perovskite solar cells. PMID:27211006

  18. BNFL Report Glass Formers Characterization

    International Nuclear Information System (INIS)

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

  19. BNFL Report Glass Formers Characterization

    Energy Technology Data Exchange (ETDEWEB)

    Schumacher, R.F.

    2000-07-27

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

  20. BNFL Report Glass Formers Characterization

    Energy Technology Data Exchange (ETDEWEB)

    Schumacher, R.F.

    2000-07-27

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

  1. BNFL Report Glass Formers Characterization

    International Nuclear Information System (INIS)

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

  2. Electrochemistry of cations in diopsidic melt - Determining diffusion rates and redox potentials from voltammetric curves

    Science.gov (United States)

    Colson, Russell O.; Haskin, Larry A.; Crane, Daniel

    1990-01-01

    Results are presented on determinations of reduction potentials and their temperature dependence of selected ions in diopsidic melt, by using linear sweep voltammetry. Diffusion coefficients were measured for cations of Eu, Mn, Cr, and In. Enthalpies and entropies of reduction were determined for the cations V(V), Cr(3+), Mn(2+), Mn(3+), Fe(2+), Cu(2+), Mo(VI), Sn(IV), and Eu(3+). Reduction potentials were used to study the structural state of cations in the melt.

  3. The interaction of gold and silver nanoparticles with a range of anionic and cationic dyes

    OpenAIRE

    Kitching, H; Kenyon, A. J.; Parkin, I. P.

    2014-01-01

    We describe the synthesis of charge-stabilised gold and silver nanoparticles by a modified Turkevich method and their interaction with a selection of cationic and anionic dyes. It was found that gold nanoparticles interact strongly with cationic dyes and in some cases enhanced absorption was observed by UV-visible spectroscopy. It is also shown that addition of cationic dyes to gold nanoparticles triggers aggregation of the nanoparticles into large, micrometre-scale clusters. Simultaneous fra...

  4. Influence of optical stimulation and irradiation on glass surface

    Science.gov (United States)

    Szarska, St.

    1994-10-01

    Gradient indices are enjoying great interest these days. The glass rods with a continuous variation of refractive index are currently used for lens systems for compact copiers, compact audio/video disc, and are expected to be applied in the near future to the more complicated systems such as cameras, binoculars, microscopes an so on. The biggest change of the glass surface can be obtained exposing the glass for the ion exchange process. When a glass slab is put into contact with a molten salt, cations of the molten salt can exchange with ions existing at the glass surface, and then the exchanged ions will migrate into the glass with in turn may change in the structure, or new ions may be different in size in polarizability and induce strains in the glass in turn may change the index. The refractive index profile depends upon the composition of the initial glass as well as the condition of ion exchange technological process. In this work 8 types silicate glass has been investigated by optical stimulation exoemission electrons. This method is sensitive for the way of preparation of the samples. Basing on this performing investigations of the physical properties of the glass before the ion exchange we propose the recommendations concerning correlation of the composition of the initial glass and optimal technological conditions of the gradient lenses production.

  5. Removal of OH Absorption Bands Due to Pyrohydrolysis Reactions in Fluoride-Containing Borosilicate Glasses

    Science.gov (United States)

    Kobayashi, Keiji

    1997-05-01

    The purpose of this study is to decrease and to remove OH ions and H2O in borosilicate glasses. Fluoride-containing borosilicate glasses followed by dry-air-bubbling showed the significant decrease of OH absorption bands around 3500 cm-1. The decrease of OH absorption bands was elucidated by the use of pyrohydrolysis reactions in these glasses where fluoride ions react with OH ions or H2O during melting. The rates of the decrease of OH absorption bands substantially depend on high valence cations of fluorides. Particularly, the decrease rates of OH absorption coefficients were in the order of ZrF4-containing glass>AlF3-containing glass>ZnF2-containing glass. ZrF4-containing glass treated by dry-air-bubbling showed a good capability to remove OH absorption band. Fluoride-containing glasses showed the low flow point in comparison with fluoride-free glasses.

  6. Cationic speciation in nonaqueous media

    International Nuclear Information System (INIS)

    Electronic spectra of solutions of d transition elements in the superacids HF, H2SO4, HSO3F, and CF3SO3H and in chloroaluminate melts indicate that in acidic monaqueous media the elements are present as solvated cations, whereas in basic media the speciation is anionic, the same situation as in aqueous solutions. Further, in very highly acidic media, cations in very low oxidation states are stable (e.g., Ti2+), but these disproportionate on addition of base to the system. In this paper spectra, where available, of U, Np, and Pu in oxidation states III and IV in aqueous media, in protonic superacids, and in chloroaluminates are presented to postulate cationic speciation of these early actinides in highly acidic media

  7. A hybrid semiconductor-glass waveguide laser

    NARCIS (Netherlands)

    Fan, Y.; Oldenbeuving, R.M.; Klein, E.J.; Lee, C.J.; Song, H.; Khan, M.R.H.; Offerhaus, H.L.; Slot, van der P.J.M.; Boller, K-J.; Mackenzie, J.I.; Jelinkova, H.; Taira, T.; Ahmed, M.A.

    2014-01-01

    abstract .We report on a novel type of laser in which a semiconductor optical amplifier (SOA) receives frequency-selective feedback from a glass-waveguide circuit. The laser we present here is based on InP for operation in the 1.55 μm wavelength range. The Si3N4/SiO2 glass waveguide circuit compris

  8. A hybrid semiconductor-glass waveguide laser

    NARCIS (Netherlands)

    Fan, Y.; Oldenbeuving, R.M.; Klein, E.J.; Lee, C.J.; Song, H.; Khan, M.R.H.; Offerhaus, H.L.; Van der Slot, P.J.M.; Boller, K.J.

    2014-01-01

    We report on a novel type of laser in which a semiconductor optical amplifier (SOA) receives frequency-selective feedback from a glass-waveguide circuit. The laser we present here is based on InP for operation in the 1.55 µm wavelength range. The Si3N4/SiO2 glass waveguide circuit comprises two sequ

  9. Selection of new glass-forming compositions in Al-La system using a combination of topological instability and thermodynamic criteria

    International Nuclear Information System (INIS)

    A combination of an extension of the topological instability 'λ criterion' and a thermodynamic criterion were applied to the Al-La system, indicating the best range of compositions for glass formation. Alloy compositions in this range were prepared by melt-spinning and casting in an arc-melting furnace with a wedge-section copper mold. The GFA of these samples was evaluated by X-ray diffraction, differential scanning calorimetry and scanning electron microscopy. The results indicated that the γ* parameter of compositions with high GFA is higher, corresponding to a range in which the λ parameter is greater than 0.1, which are compositions far from Al solid solution. A new alloy was identified with the best GFA reported so far for this system, showing a maximum thickness of 286 μm in a wedge-section copper mold.

  10. Stimulation of cation transport in mitochondria by gramicidin and truncated derivatives

    International Nuclear Information System (INIS)

    Gramicidin and the truncated derivatives desformylgramicidin (desfor) and des(formylvalyl)gramicidin (desval) stimulate monovalent cation transport in rat liver mitochondria. Cation fluxes were compared indirectly from the effect of cations on the membrane potential at steady state (state 4) or from the associated stimulation of electron transport. Rb+ transport was measured directly from the uptake of 86Rb. The truncated gramicidins show enhanced selectivity for K+ and Rb+ when compared to gramicidin. Moreover, the pattern of selectivity within the alkali cation series is altered. The cation fluxes through the truncated derivatives are more strongly dependent on the cation concentration. The presence of high concentrations of permeating cation enhances the transport of other cations through the truncated derivative channels, suggesting that cations are required for stabilizing the channel structure. In high concentrations of KCl, desfor and desval are nearly as effective as gramicidin in collapsing the mitochondrial membrane potential, and consequently, in the uncoupling of oxidative phosphorylation and enhancement of ATP hydrolysis. Preliminary experiments with liposomes show that 86Rb exchange is stimulated by desfor and desval almost to the same extend at gramicidin. These results strongly suggest that the truncated gramicidins form a novel conducting channel which differs from the gramicidin head-to-head, single-stranded β6.3-helical dimer (channel) in its conductance characteristic and its structure. On the basis of the secondary structure of the truncated derivatives, the authors suggest that the antiparallel double-stranded helix dimer (pore) is a likely alternative structure for this novel channel

  11. Research progress in cation-π interactions

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    Cation-π interaction is a potent intermolecular interaction between a cation and an aromatic system,which has been viewed as a new kind of binding force,as being compared with the classical interactions(e.g. hydrogen bonding,electrostatic and hydrophobic interactions). Cation-π interactions have been observed in a wide range of biological contexts. In this paper,we present an overview of the typical cation-π interactions in biological systems,the experimental and theoretical investigations on cation-π interactions,as well as the research results on cation-π interactions in our group.

  12. Fixation by ION exchange of toxic materials in a glass matrix

    International Nuclear Information System (INIS)

    This invention relates to the immobilization of toxic, e.g., radioactive, materials in a silicate glass or silica gel matrix for extremely long periods of time. Toxic materials, such as radioactive wastes containing radioactive cations, which may be in the form of liquids, or solids dissolved or dispersed in liquids or gases, are incorporated into a glass or silica gel matrix, having alkali metal, Group Ib metal and/or ammonium cations bonded to silicon atoms of said glass or silica gel through divalent oxygen linkages, by a process which involves the ion exchange of said toxic or radioactive cations with said alkali metal, Group Ib metal and/or ammonium cations to bind said toxic or radioactive cations to silicon atoms of said glass or silica gel through said silicon-bonded divalent oxygen linkages. Thereafter, the resulting glass or silica gel now characterized by toxic or radioactive cations bonded to silicon atoms through divalent oxygen linkages can be stored, or packaged in suitable containers, or disposed of as by burial, and/or sintered to collapse the pores thereof

  13. 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.

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

    Directory of Open Access Journals (Sweden)

    Inès M. M. M. Ponsot

    2014-07-01

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

  15. Plastic Membrane Sensor from a Disposed Combined Glass Electrode

    Science.gov (United States)

    Marafie, Hayat M.; Shoukry, Adel F.; Alshatti, Laila A.

    2007-01-01

    The construction of combined plastic membrane electrode for hydralazinium cation from a disposed glass electrode is described. A variety of electrodes could be prepared by students using other types of polymers, plasticizers, or exchangers which could also help to study effects of pH and temperature, or environmental investigations.

  16. Effects of solar radiation on glass

    Science.gov (United States)

    Tucker, Dennis S.; Kinser, Donald L.

    1991-01-01

    The effects of solar radiation of selected glasses are reported. Optical property degradation is studied using UV-Vis spectrophotometry. Strength changes are measured using a concentric ring bend test. Direct fracture toughness measurements using an indentation test are planned.

  17. Cutting glass by laser

    Science.gov (United States)

    Kang, Hyoung-Shik; Hong, Soon-Kug; Oh, Seok-Chang; Choi, Jong-Yoon; Song, Min-Gyu

    2002-02-01

    In FPD (Flat Panel Display) devices, the diamond wheel has been used to scribe glass by means of mechanical contact which needs grinding and cleaning processes to remove particles, glass chips, surface cracks and sharp edges. In recent years, laser glass technology that is different from the conventional method of cutting glass by melting, has been researched and utilizes cutting glass by thermal shock. Laser glass cutting by thermal shock can produce cracks in glass by surface cooling after laser heating on glass by means of stress slope on glass surface. When this technology is applied in FPD manufacturing devices, it has several advantages compared to conventional methods as follows: a) non-contact glass cutting: almost no glass chip occurs. b) according to circumstances, grinding and cleaning can be omitted. c) system maintenance can be simplified.

  18. Apollo 16 Mafic Glass: Geochemistry, Provenance, and Implications

    Science.gov (United States)

    Zeigler, R. A.; Korotev, R. L.; Jolliff, B. L.; Haskin, L. A.; Floss, C.

    2004-01-01

    Although the Apollo 16 mission landed in the feldspathic lunar highlands, mass-balance models suggest that there is a 5-6% mare component in the mature soils collected at the site. Only one mare basalt greater than 1 cm was found and two surveys of 2-4 mm particles found that less than 1% of this size fraction is mare basalt. Similar surveys of the less than 1 mm size fraction of A16 soils found very little lithic mare basalt, but several percent of basaltic green, yellow, and orange glass. The green glass beads were identified as VLT picritic glass and the orange/yellow glass shards were a mix of high and low Ti mare-like glass, high-Al basaltic glass, and KREEPy glasses. Most previous studies of glasses in the A16 regolith were surveys that identified a high proportion of feldspathic glass because most of the glass is produced by local impacts. Because the number of mafic glasses found was low, few compositional groupings were identified. As part of our ongoing study of the mafic components of the Apollo 16 site, we specifically targeted mafic glasses from Apollo 16, selecting against the more feldspathic glasses. In this way we were able to identify over 300 mafic glasses (greater than 10 wt % FeO). We present here the major- and trace-element chemistry of the main glass groups and discuss the likely provenance of each group.

  19. Cationic Antimicrobial Polymers and Their Assemblies

    Directory of Open Access Journals (Sweden)

    Ana Maria Carmona-Ribeiro

    2013-05-01

    Full Text Available Cationic compounds are promising candidates for development of antimicrobial agents. Positive charges attached to surfaces, particles, polymers, peptides or bilayers have been used as antimicrobial agents by themselves or in sophisticated formulations. The main positively charged moieties in these natural or synthetic structures are quaternary ammonium groups, resulting in quaternary ammonium compounds (QACs. The advantage of amphiphilic cationic polymers when compared to small amphiphilic molecules is their enhanced microbicidal activity. Besides, many of these polymeric structures also show low toxicity to human cells; a major requirement for biomedical applications. Determination of the specific elements in polymers, which affect their antimicrobial activity, has been previously difficult due to broad molecular weight distributions and random sequences characteristic of radical polymerization. With the advances in polymerization control, selection of well defined polymers and structures are allowing greater insight into their structure-antimicrobial activity relationship. On the other hand, antimicrobial polymers grafted or self-assembled to inert or non inert vehicles can yield hybrid antimicrobial nanostructures or films, which can act as antimicrobials by themselves or deliver bioactive molecules for a variety of applications, such as wound dressing, photodynamic antimicrobial therapy, food packing and preservation and antifouling applications.

  20. Photodissociation of Cerium Oxide Nanocluster Cations.

    Science.gov (United States)

    Akin, S T; Ard, S G; Dye, B E; Schaefer, H F; Duncan, M A

    2016-04-21

    Cerium oxide cluster cations, CexOy(+), are produced via laser vaporization in a pulsed nozzle source and detected with time-of-flight mass spectrometry. The mass spectrum displays a strongly preferred oxide stoichiometry for each cluster with a specific number of metal atoms x, with x ≤ y. Specifically, the most prominent clusters correspond to the formula CeO(CeO2)n(+). The cluster cations are mass selected and photodissociated with a Nd:YAG laser at either 532 or 355 nm. The prominent clusters dissociate to produce smaller species also having a similar CeO(CeO2)n(+) formula, always with apparent leaving groups of (CeO2). The production of CeO(CeO2)n(+) from the dissociation of many cluster sizes establishes the relative stability of these clusters. Furthermore, the consistent loss of neutral CeO2 shows that the smallest neutral clusters adopt the same oxidation state (IV) as the most common form of bulk cerium oxide. Clusters with higher oxygen content than the CeO(CeO2)n(+) masses are present with much lower abundance. These species dissociate by the loss of O2, leaving surviving clusters with the CeO(CeO2)n(+) formula. Density functional theory calculations on these clusters suggest structures composed of stable CeO(CeO2)n(+) cores with excess oxygen bound to the surface as a superoxide unit (O2(-)). PMID:27035210

  1. On the chemical variability of Middelburg glass beads and rods

    International Nuclear Information System (INIS)

    Forty-three glass samples from a late 16th-early 17th century, glass beadmaking house in Middelburg, the Netherlands, were selected for maximum colouring variability, including plain and multi-coloured varieties. The glass chemistries were quite diverse, within each colour grouping. For each single colour of glass, anticipated colouring elements (copper for turquoise blue, cobalt for dark blue, manganese for rose, and tin for white) were used, with the exception of two beads that were opacified wih antimony rather than with tin. Multi-coloured glass glasses (chevron beads) produced chemistries that match the mixing of the different coloured glasses. In some cases, low relative amounts of some inter-mixed glasses were not detectable against the composition of the major glass component. (author). 16 refs., 3 tabs

  2. Thermoset composite recycling: Properties of recovered glass fiber

    OpenAIRE

    Beauson, Justine; Fraisse, Anthony; Toncelli, C.; Bech, Jakob Ilsted; Brøndsted, Povl

    2015-01-01

    Recycling of glass fiber thermoset polymer composite is a challenging topic and a process able to recover the glass fibers original properties in a limited cost is still under investigation. This paper focuses on the recycling technique separating the glass fiber from the matrix material. Four different recycling processes, mechanical, burn off, pyrolysis and glycolysis are selected are compared based on the properties of the glass fiber recovered. The intention is to use the same characteriz...

  3. Active glass for photonic devices photoinduced structures and their application

    CERN Document Server

    Mitsuyu, Tsuneo; Si, Jinhai; Qiu, Jianrong

    2001-01-01

    This book focuses on selected topics which are new and of fundamental importance in the application of active glasses in photonic devices Most of the chapters deal with glasses under the action of higher electromagnetic fields, such as those produced by femtosecond lasers They cover the creation and analysis of induced structures in glasses and some functional devices using active glasses This book is designed for both graduate students and researchers in the field

  4. Polyelectrolyte Condensation Induced by Linear Cations

    OpenAIRE

    Guáqueta, Camilo; Luijten, Erik

    2007-01-01

    We examine the role of the condensing agent in the formation of polyelectrolyte bundles, via grand-canonical Monte Carlo simulations. Following recent experiments we use linear, rigid divalent cations of various lengths to induce condensation. Our results clarify and explain the experimental results for short cations. For longer cations we observe novel condensation behavior owing to alignment of the cations. We also study the role of the polyelectrolyte surface charge density, and find a non...

  5. Infrared spectra of glass of the RO-Nd(PO3)3-SiP2O7

    International Nuclear Information System (INIS)

    The RO-Nd(PO3)3-SiP2O7 (R=Mg, Ca, Zn, Sr, Cd, Ba) system glasses were investigated by the method of infrared spectroscopy. On the basis of the obtained data the suggestion has been made concerning the influence of R2+ cations on the polymerization process of the title system glasses. The dependence of the polymerization process on the concentration and the possible changes of coordination numbers of cations has been established

  6. Drug loading to lipid-based cationic nanoparticles

    International Nuclear Information System (INIS)

    Lipid-based cationic nanoparticles are a new promising option for tumor therapy, because they display enhanced binding and uptake at the neo-angiogenic endothelial cells, which a tumor needs for its nutrition and growth. By loading suitable cytotoxic compounds to the cationic carrier, the tumor endothelial and consequently also the tumor itself can be destroyed. For the development of such novel anti-tumor agents, the control of drug loading and drug release from the carrier matrix is essential. We have studied the incorporation of the hydrophobic anti-cancer agent Paclitaxel (PXL) into a variety of lipid matrices by X-Ray reflectivity measurements. Liposome suspensions from cationic and zwitterionic lipids, comprising different molar fractions of Paclitaxel, were deposited on planar glass substrates. After drying at controlled humidity, well ordered, oriented multilayer stacks were obtained, as proven by the presence of bilayer Bragg peaks to several orders in the reflectivity curves. The presence of the drug induced a decrease of the lipid bilayer spacing, and with an excess of drug, also Bragg peaks of drug crystals could be observed. From the results, insight into the solubility of Paclitaxel in the model membranes was obtained and a structural model of the organization of the drug in the membrane was derived. Results from subsequent pressure/area-isotherm and grazing incidence diffraction (GID) measurements performed with drug/lipid Langmuir monolayers were in accordance with these conjectures

  7. SODIUM ENVIRONMENTS IN GLASS

    OpenAIRE

    Greaves, G.

    1981-01-01

    Sodium environments have been measured directly in several oxide glasses using EXAFS at the sodium K edge. The existence of local structure around sodium in glass contradicts the conventional Zachariasen model. Analysis of the EXAFS indicates there are significant differences relating to the glass modifier : glass former chemistry - the details of which demonstrate similarities with crystalline silicates and borates.

  8. Cationic electrodepositable coating composition comprising lignin

    Science.gov (United States)

    Fenn, David; Bowman, Mark P; Zawacky, Steven R; Van Buskirk, Ellor J; Kamarchik, Peter

    2013-07-30

    A cationic electrodepositable coating composition is disclosed. The present invention in directed to a cationic electrodepositable coating composition comprising a lignin-containing cationic salt resin, that comprises (A) the reaction product of: lignin, an amine, and a carbonyl compound; (B) the reaction product of lignin, epichlorohydrin, and an amine; or (C) combinations thereof.

  9. Organometallic cation-exchanged phyllosilicates

    OpenAIRE

    Fleming, Shay

    1991-01-01

    Organotin (IV) complexes formed between 0 01 M dimethyltin dichloride solutions prepared at pH 2 6 and 4 0, and trimethyltin chloride prepared at pH 3 4, with Na- 119 montmori 1lonite clay have been characterised using Sn Mflssbauer spectroscopy, X-ray diffraction, thermogravimetric analysis and water sorption isotherms Following cation exchange, Mttssbauer spectroscopy identified two tin species in the dimethyltin (IV)-exchanged clay prepared at pH 2 6 A cis specie...

  10. Calorimetric study of cationic photopolymerization

    International Nuclear Information System (INIS)

    The photopolymerization of penta-erythritol tetra-glycidyl ether (initiator Degacure KI-85) was studied by a du Pont 910 type DSC. From our experimental results the following conclusions can be drawn: (1) During the cationic polymerization reaction the lifetime of the initiating centers are long compared to the lifetime of free radicals in case of radical polymerization. (2) The rate of deactivation of the initiating centers increases with increasing temperature. (author)

  11. Inverted glass harp

    Science.gov (United States)

    Quinn, Daniel B.; Rosenberg, Brian J.

    2015-08-01

    We present an analytical treatment of the acoustics of liquid-filled wine glasses, or "glass harps." The solution is generalized such that under certain assumptions it reduces to previous glass harp models, but also leads to a proposed musical instrument, the "inverted glass harp," in which an empty glass is submerged in a liquid-filled basin. The versatility of the solution demonstrates that all glass harps are governed by a family of solutions to Laplace's equation around a vibrating disk. Tonal analyses of recordings for a sample glass are offered as confirmation of the scaling predictions.

  12. Recycling glass packaging

    OpenAIRE

    Monica Delia DOMNICA; Leila BARDAªUC

    2015-01-01

    From the specialized literature it follows that glass packaging is not as used as other packages, but in some industries are highly needed. Following, two features of glass packaging will become important until 2017: the shape of the glass packaging and glass recycling prospects in Romania. The recycling of glass is referred to the fact that it saves energy, but also to be in compliance with the provisions indicating the allowable limit values for the quantities of lead and cadmium.

  13. Selective extraction of calcium on tri-n-butyl phosphate plasticized selective extraction of calcium on tri-n-butyl phosphate plasticized polyurethane foam for its spectrophotometric determination in glass and ceramics.

    Science.gov (United States)

    Mondal, Jayanta K; Kundu, Dipali

    2005-12-01

    The present paper describes the application of a solid phase extraction system in order to separate traces of calcium from glass and ceramics for its spectrophotometric determination. The method is based on the extraction of calcium from sodium hydroxide solution by tri-n-butyl phosphate (TBP) loaded polyurethane foam (PUF), followed by its elution in hydrochloric acid. The spectrophotometric measurement of the absorbance of calcium complex with calconcarboxylic acid (2-hydroxy-1-(2-hydroxy-4-sulfo-1-naphthylazo)-3-naphthoic acid) takes place at pH 12. The following parameters were studied: effects of sodium hydroxide concentration and temperature on the extraction of calcium, time of equilibration for quantitative calcium extraction, effect of TBP concentration, effect of hydrochloric acid concentration for quantitative elution of calcium from PUF, effect of pH and concentration of calconcarboxylic acid for quantitative formation of the complex with calcium, effect of acetone on the stability of calcium-calconcarboxylic acid complex and influence of diverse ions on calcium sorption by TBP-loaded PUF. The results show that calcium traces can be separated onto TBP-loaded PUF from 0.25 mol L(-1) NaOH at 30 +/- 5 degrees C within 30 min. PUF was loaded with TBP in CCl4 (40% v/v). Elution of calcium was done in 1.0 mol l(-1) HCl. The calcium formed a complex with calconcarboxylic acid at pH 12 and absorbance was measured at 560 nm in acetone-water medium. Molar absorptivity was found to be 1.082 x 10(4) l mol(-1) cm(-1). The method obeys Beer's law from 0.10 to 5.0 microg ml(-1) Ca. The validity of the method was established by its successful application in NIST standard reference materials. The method proposed was applied to determine calcium in glass and ceramic materials. The results of the proposed method are comparable with the results of ICP-AES analysis and they are found to be in good agreement. PMID:16379392

  14. Investigation into two-component phosphate glasses by X-ray electron spectroscopy

    International Nuclear Information System (INIS)

    Using the method of X-ray electron spectroscopy double glass-like and certain crystal phosphates containing mono and bivalent cations are investigated. The identity of spectra of frame levels and valents band of glass-like and crystal analogues points to the preservation of the near order in glasses. Using the method, bridge and non-bridge oxygen atoms (P-O-R and P=O) can be discriminated in glass-like and crystal phosphates containing mono- and bivalent cations, but it is quite impossible to distinguish the bonds P-O-R and P=O. The chemical shift 01 s in bicomponent phosphate glasses increases with an increase in the modifier content. In the case of alkali-earth ions the chemical shift 01s is determined by the sequene Be→Mg→Ca→Sr→Ba. The chemical shift P2p increases with an increase in the number of non-bridge oxygen atoms

  15. Structural classification of phosphate glasses

    International Nuclear Information System (INIS)

    A structural classification of phosphate glasses is proposed. Following types of phosphate glasses are distinguished: discontinuous polymeric structure glasses (phosphate and mixed chains and rings containing glasses), continuous spatial network structure glasses (ultraphosphate and mixed network glasses) and non-polymeric structure glasses (oxide-halide and halide glasses, stuffed with ortho- and pyrophosphate-like groups). Type of the structure determines in a considerable degree the relation between glass composition and properties. (author). 25 refs

  16. Behavior of dialysis for the rare earth elements in cationic membranes

    International Nuclear Information System (INIS)

    In this work it is presented a dialysis process as an alternative method for the fractionation of rare earth elements. The used cell was set up with a transparent Pyrex glass cylinder with the membrane set in one extreme and using another glass chamber to collect the dialyzed solute. Cationic Membrane: NafionR 324 manufactured by Dupont and IonacR MC-3470XL from Sybron Chemicals were used. A series of exploratory experiments allowed concluding that there was some different behavior as function of the nature of the rare earth solutions, i.e, whether the solutions contained nitrate, sulfate or chloride. (author)

  17. Cationic cellulose nanofibers from waste pulp residues and their nitrate, fluoride, sulphate and phosphate adsorption properties.

    Science.gov (United States)

    Sehaqui, Houssine; Mautner, Andreas; Perez de Larraya, Uxua; Pfenninger, Numa; Tingaut, Philippe; Zimmermann, Tanja

    2016-01-01

    Cationic cellulose nanofibers (CNF) having 3 different contents of positively charged quaternary ammonium groups have been prepared from waste pulp residues according to a water-based modification method involving first the etherification of the pulp with glycidyltrimethylammonium chloride followed by mechanical disintegration. The cationic nanofibers obtained were observed by scanning electron microscopy and the extent of the reaction was evaluated by conductometric titration, ζ-potential measurements, and thermogravimetric analyses. The cationic CNF had a maximum cationic charge content of 1.2mmolg(-1) and positive ζ-potential at various pH values. Sorption of negatively charged contaminants (fluoride, nitrate, phosphate and sulphate ions) and their selectivity onto cationic CNF have been evaluated. Maximum sorption of ∼0.6mmolg(-1) of these ions by CNF was achieved and selectivity adsorption studies showed that cationic CNF are more selective toward multivalent ions (PO4(3-) and SO4(2-)) than monovalent ions (F(-) and NO3(-)). In addition, we demonstrated that cationic CNF can be manufactured into permeable membranes capable of dynamic nitrate adsorption by utilizing a simple paper-making process. PMID:26453885

  18. Carbon-Based Solid-State Calcium Ion-Selective Microelectrode and Scanning Electrochemical Microscopy: A Quantitative Study of pH-Dependent Release of Calcium Ions from Bioactive Glass.

    Science.gov (United States)

    Ummadi, Jyothir Ganesh; Downs, Corey J; Joshi, Vrushali S; Ferracane, Jack L; Koley, Dipankar

    2016-03-15

    Solid-state ion-selective electrodes are used as scanning electrochemical microscope (SECM) probes because of their inherent fast response time and ease of miniaturization. In this study, we report the development of a solid-state, low-poly(vinyl chloride), carbon-based calcium ion-selective microelectrode (Ca(2+)-ISME), 25 μm in diameter, capable of performing an amperometric approach curve and serving as a potentiometric sensor. The Ca(2+)-ISME has a broad linear response range of 5 μM to 200 mM with a near Nernstian slope of 28 mV/log[a(Ca(2+))]. The calculated detection limit for Ca(2+)-ISME is 1 μM. The selectivity coefficients of this Ca(2+)-ISME are log K(Ca(2+),A) = -5.88, -5.54, and -6.31 for Mg(2+), Na(+), and K(+), respectively. We used this new type of Ca(2+)-ISME as an SECM probe to quantitatively map the chemical microenvironment produced by a model substrate, bioactive glass (BAG). In acidic conditions (pH 4.5), BAG was found to increase the calcium ion concentration from 0.7 mM ([Ca(2+)] in artificial saliva) to 1.4 mM at 20 μm above the surface. In addition, a solid-state dual SECM pH probe was used to correlate the release of calcium ions with the change in local pH. Three-dimensional pH and calcium ion distribution mapping were also obtained by using these solid-state probes. The quantitative mapping of pH and Ca(2+) above the BAG elucidates the effectiveness of BAG in neutralizing and releasing calcium ions in acidic conditions. PMID:26861499

  19. lead glass brick

    CERN Multimedia

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

  20. An extended topological model for binary phosphate glasses

    International Nuclear Information System (INIS)

    We present a topological model for binary phosphate glasses that builds on the previously introduced concepts of the modifying ion sub-network and the strength of modifier constraints. The validity of the model is confirmed by the correct prediction of Tg(x) for covalent polyphosphoric acids where the model reduces to classical constraint counting. The constraints on the modifying cations are linear constraints to first neighbor non-bridging oxygens, and all angular constraints are broken as expected for ionic bonding. For small modifying cations, such as Li+, the linear constraints are almost fully intact, but for larger ions, a significant fraction is broken. By accounting for the fraction of intact modifying ion related constraints, qγ, the Tg(x) of alkali phosphate glasses is predicted. By examining alkali, alkaline earth, and rare earth metaphosphate glasses, we find that the effective number of intact constraints per modifying cation is linearly related to the charge-to-distance ratio of the modifying cation to oxygen

  1. Use of laser induced photoacoustic spectroscopy (LIPAS) to determine equilibrium constants of cation-cation complexes

    International Nuclear Information System (INIS)

    Laser Induced PhotoAcoustic Spectroscopy (LIPAS) is a relatively new, photothermal technique to examine solutions. Studies in the past have shown it to be more sensitive than conventional absorption spectroscopy, while, yielding the same information thus allowing lower concentrations to be used. This study is using LIPAS to examine solutions to determine the equilibrium constants of cation-cation complexes. It has been found that actinyl(V) cations form cation-cation complexes with a variety of cations, including actinyl(VI) cations. The radioactive nature of the actinide elements requires special handling techniques and also require limits be placed on the amount of material that can be used. The sensitivity of some oxidation states of the actinides to oxygen also presents a problem. Preliminary results will be presented for actinyl(V)-actinyl(VI) cation-cation complexes that were studied using a remote LIPAS system incorporating fiber optics for transmission of laser signals

  2. 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

  3. The Free Tricoordinated Silyl Cation Problem

    Directory of Open Access Journals (Sweden)

    Čičak, H.

    2010-03-01

    Full Text Available As the importance and abundance of silicon in our environment is large, it has been thought that silicon might take the place of carbon in forming a host of similar compounds and silicon-based life. However, until today there is no experimental evidence for such a hypothesis and carbon is still unique among the elements in the vast number and variety of compounds it can form. Also, the corresponding derivatives of the two elements show considerable differences in their chemical properties.The essential debate concerning organosilicon chemistry relates to the existence of the free planar tricoordinated silyl cations in condensed phase (R3Si+, in analogy to carbocations (R3C+ which have been known and characterized as free species. Although silyl cations are thermodynamically more stable than their carbon analogs, they are very reactive due to their high inherent electrophilicity and the ability of hypervalent coordination. On the other hand, stabilization by inductive and hyperconjugative effects and larger steric effects of carbocations make them less sensitive to solvation or other environmental effects than silyl cations. Hence, observation of free silyl cations in the condensed phase proved extremely difficult and the actual problem is the question of the degree of the (remaining silyl cation character.The first free silyl cation, trimesitylsilyl cation, and in analogy with it tridurylsilyl cation, were synthesized by Lambert et al. Free silyl cations based on analogy to aromatic ions (homocyclopropenylium and tropylium have also been prepared. However, in these silyl cations the cationic character is reduced by internal π -conjugation. Čičak et al. prepared some silyl-cationic intermediates (Me3Si--CH≡CR+in solid state. With the help of quantum-mechanical calculations it was concluded that these adducts have much more silyl cation than carbocation character.

  4. Oxynitride glass fibers

    Science.gov (United States)

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

    1991-01-01

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

  5. Fluorescence properties of Eu3+ ions doped borate and fluoroborate glasses containing lithium, zinc and lead.

    Science.gov (United States)

    Venkatramu, V; Babu, P; Jayasankar, C K

    2006-02-01

    The influence of glass composition on the fluorescence properties of Eu3+ ions doped borate and fluoroborate glasses modified with Li+, Zn2+ and Pb2+ cations have been investigated. The magnitude of splittings of 7F1 levels are analyzed using crystal-field (CF) analysis. The relative intensities of 5D0 --> 7F2 to 5D0 --> 7F1 transitions, crystal-field strength parameters and decay times of the 5D0 level have been determined and are found to be lower for Pb based glasses than those of Zn/Li based glasses. The lifetimes of 5D0 level are found to increase when borate glasses are modified with pure fluorides than with oxides and oxyfluorides. The fluorescence decay of 5D0 level fits perfect single exponential in the Eu3+:glass systems studied which indicates the absence of energy transfer between Eu3+ ions in these glasses. PMID:15979397

  6. Microstructuring of glasses

    CERN Document Server

    Hülsenberg, Dagmar; Bismarck, Alexander

    2008-01-01

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

  7. Modifier constraints in alkali ultraphosphate glasses

    DEFF Research Database (Denmark)

    Rodrigues, B.P.; Mauro, J.C.; Yue, Yuanzheng;

    2014-01-01

    In applying the recently introduced concept of cationic constraint strength [J. Chem. Phys. 140, 214501 (2014)] to bond constraint theory (BCT) of binary phosphate glasses in the ultraphosphate region of xR2O-(1-x)P2O5 (with x ≤ 0.5 and R = {Li, Na, Cs}), we demonstrate that a fundamental...... limitation of BCT can be overcome. The modifiers are considered to exist in either “isolated” or “crosslinking” sites, in line with the so-called modifier sub-network [J. Chem. Phys. 140, 154501 (2014)] and each site is associated with a certain number of constraints. We estimate the compositional dependence...

  8. Reduction-induced inward diffusion and crystal growth on the surfaces of iron-bearing silicate glasses

    DEFF Research Database (Denmark)

    Liu, S.J.; Tao, H.Z.; Zhang, Y.F.; Yue, Yuanzheng

    2015-01-01

    We investigate the sodium inward diffusion (i.e., sodium diffusion from surface toward interior) in iron containing alkaline earth silicate glasses under reducing conditions around Tg and the induced surface crystallization. The surface crystallization is caused by formation of a silicate-gel layer...... first and then the growth of silica crystals on the glass surface. The type of alkaline earth cations has a strong impact on both the glass transition and the surface crystallization. In the Mg-containing glass, a quartz layer forms on the glass surface. This could be attributed to the fact that Mg2...

  9. Chalcogenide glass microsphere laser

    OpenAIRE

    Elliott, Gregor R.; Murugan, G.Senthil; Wilkinson, James S.; Zervas, Michalis N.; Hewak, Daniel W.

    2010-01-01

    Laser action has been demonstrated in chalcogenide glass microsphere. A sub millimeter neodymium-doped gallium lanthanum sulphide glass sphere was pumped at 808 nm with a laser diode and single and multimode laser action demonstrated at wavelengths between 1075 and 1086 nm. The gallium lanthanum sulphide family of glass offer higher thermal stability compared to other chalcogenide glasses, and this, along with an optimized Q-factor for the microcavity allowed laser action to be achieved. When...

  10. Anti-inflammatory activity of cationic lipids

    OpenAIRE

    Filion, Mario C; Phillips, Nigel C

    1997-01-01

    The effect of liposome phospholipid composition has been assumed to be relatively unimportant because of the presumed inert nature of phospholipids.We have previously shown that cationic liposome formulations used for gene therapy inhibit, through their cationic component, the synthesis by activated macrophages of the pro-inflammatory mediators nitric oxide (NO) and tumour necrosis factor-α (TNF-α).In this study, we have evaluated the ability of different cationic lipids to reduce footpad inf...

  11. Chemical Surface, Thermal and Electrical Characterization of Nafion Membranes Doped with IL-Cations

    Directory of Open Access Journals (Sweden)

    María del Valle Martínez de Yuso

    2014-04-01

    Full Text Available Surface and bulk changes in a Nafion membrane as a result of IL-cation doping (1-butyl-3-methylimidazolium tetrafluoroborate or BMIM+BF4 and phenyltrimethylammonium chloride or TMPA+Cl− were studied by X-ray photoelectron spectroscopy (XPS, contact angle, differential scanning calorimetry (DSC and impedance spectroscopy (IS measurements performed with dry samples after 24 h in contact with the IL-cations BMIM+ and TMPA+. IL-cations were selected due to their similar molecular weight and molar volume but different shape, which could facilitate/obstruct the cation incorporation in the Nafion membrane structure by proton/cation exchange mechanism. The surface coverage of the Nafion membrane by the IL-cations was confirmed by XPS analysis and contact angle, while the results obtained by the other two techniques (DSC and IS seem to indicate differences in thermal and electrical behaviour depending on the doping-cation, being less resistive the Nafion/BMIM+ membrane. For that reason, determination of the ion transport number was obtained for this membrane by measuring the membrane or concentration potential with the samples in contact with HCl solutions at different concentrations. The comparison of these results with those obtained for the original Nafion membrane provides information on the effect of IL-cation BMIM+ on the transport of H+ across wet Nafion/BMIM+ doped membranes.

  12. Effect of glass composition on waste form durability: A critical review

    Energy Technology Data Exchange (ETDEWEB)

    Ellison, A.J.G.; Mazer, J.J.; Ebert, W.L. [Argonne National Lab., IL (United States). Chemical Technology Div.

    1994-11-01

    This report reviews literature concerning the relationship between the composition and durability of silicate glasses, particularly glasses proposed for immobilization of radioactive waste. Standard procedures used to perform durability tests are reviewed. It is shown that tests in which a low-surface area sample is brought into contact with a very large volume of solution provide the most accurate measure of the intrinsic durability of a glass composition, whereas high-surface area/low-solution volume tests are a better measure of the response of a glass to changes in solution chemistry induced by a buildup of glass corrosion products. The structural chemistry of silicate and borosilicate glasses is reviewed to identify those components with the strongest cation-anion bonds. A number of examples are discussed in which two or more cations engage in mutual bonding interactions that result in minima or maxima in the rheologic and thermodynamic properties of the glasses at or near particular optimal compositions. It is shown that in simple glass-forming systems such interactions generally enhance the durability of glasses. Moreover, it is shown that experimental results obtained for simple systems can be used to account for durability rankings of much more complex waste glass compositions. Models that purport to predict the rate of corrosion of glasses in short-term durability tests are evaluated using a database of short-term durability test results for a large set of glass compositions. The predictions of these models correlate with the measured durabilities of the glasses when considered in large groupings, but no model evaluated in this review provides accurate estimates of durability for individual glass compositions. Use of these models in long-term durability models is discussed. 230 refs.

  13. Effect of glass composition on waste form durability: A critical review

    International Nuclear Information System (INIS)

    This report reviews literature concerning the relationship between the composition and durability of silicate glasses, particularly glasses proposed for immobilization of radioactive waste. Standard procedures used to perform durability tests are reviewed. It is shown that tests in which a low-surface area sample is brought into contact with a very large volume of solution provide the most accurate measure of the intrinsic durability of a glass composition, whereas high-surface area/low-solution volume tests are a better measure of the response of a glass to changes in solution chemistry induced by a buildup of glass corrosion products. The structural chemistry of silicate and borosilicate glasses is reviewed to identify those components with the strongest cation-anion bonds. A number of examples are discussed in which two or more cations engage in mutual bonding interactions that result in minima or maxima in the rheologic and thermodynamic properties of the glasses at or near particular optimal compositions. It is shown that in simple glass-forming systems such interactions generally enhance the durability of glasses. Moreover, it is shown that experimental results obtained for simple systems can be used to account for durability rankings of much more complex waste glass compositions. Models that purport to predict the rate of corrosion of glasses in short-term durability tests are evaluated using a database of short-term durability test results for a large set of glass compositions. The predictions of these models correlate with the measured durabilities of the glasses when considered in large groupings, but no model evaluated in this review provides accurate estimates of durability for individual glass compositions. Use of these models in long-term durability models is discussed. 230 refs

  14. The role of a low-energy–density re-scan in fabricating crack-free Al85Ni5Y6Co2Fe2 bulk metallic glass composites via selective laser melting

    International Nuclear Information System (INIS)

    Highlights: • We proposed a re-scan strategy to prevent crack propagation in SLM. • The re-scan should be carried out at a low laser energy density. • The underlying mechanism is through reduction and relief of residual stresses. • Lowered temperature gradient and superplasticity account for reduction of stress. • For the first time, a crack-free BMGCs gear with a large size was produced. - Abstract: In this paper, we have investigated the use of a re-scanning strategy to prevent propagation of macro-cracks during the selective laser melting of an Al85Ni5Y6Co2Fe2 bulk metallic glass composites (BMGCs). These cracks form as a result of the high residual stress caused by the rapid heating and cooling of the material by the laser beam. Unlike crystalline materials, the BMGCs possess a supercooled liquid region in which the residual stress can be relieved by plastic flow. We show that by using a high power initial scan (designed to melt the material) followed by a lower power re-scan (for stress relief) cracking can be prevented. Using this approach, crack-free Al85Ni5Y6Co2Fe2 BMGCs components have been fabricated, including a gear with a diameter ∼25 mm and height ∼10 mm

  15. Selective laser melting of an Al{sub 86}Ni{sub 6}Y{sub 4.5}Co{sub 2}La{sub 1.5} metallic glass: Processing, microstructure evolution and mechanical properties

    Energy Technology Data Exchange (ETDEWEB)

    Li, X.P., E-mail: xiaopeng.li@uwa.edu.au [The University of Western Australia, School of Mechanical and Chemical Engineering, Perth, WA 6009 (Australia); Kang, C.W.; Huang, H. [The University of Queensland, School of Mechanical and Mining Engineering, Brisbane, Qld. 4072 (Australia); Zhang, L.C. [Edith Cowan University, School of Mechanical Engineering, Perth, WA 6027 (Australia); Sercombe, T.B. [The University of Western Australia, School of Mechanical and Chemical Engineering, Perth, WA 6009 (Australia)

    2014-06-01

    In this study, single line scans at different laser powers were carried out using selective laser meting (SLM) equipment on a pre-fabricated porous Al{sub 86}Ni{sub 6}Y{sub 4.5}Co{sub 2}La{sub 1.5} metallic glass (MG) preform. The densification, microstructural evolution, phase transformation and mechanical properties of the scan tracks were systematically investigated. It was found that the morphology of the scan track was influenced by the energy distribution of the laser beam and the heat transfer competition between convection and conduction in the melt pool. Due to the Gaussian distribution of laser energy and heat transfer process, different regions of the scan track experienced different thermal histories, resulting in a gradient microstructure and mechanical properties. Higher laser powers caused higher thermal stresses, which led to the formation of cracks; while low power reduced the strength of the laser track, also inducing cracking. The thermal fluctuation at high laser power produced an inhomogeneous chemical distribution which gave rise to severe crystallization of the MG, despite the high cooling rate. The crystallization occurred both within the heat affected zone (HAZ) and at the edge of melt pool. However, by choosing an appropriate laser power crack-free scan tracks could be produced with no crystallization. This work provides the necessary fundamental understanding that will lead to the fabrication of large-size, crack-free MG with high density, controllable microstructure and mechanical properties using SLM.

  16. Homogeneity of Inorganic Glasses

    DEFF Research Database (Denmark)

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

    2011-01-01

    Homogeneity of glasses is a key factor determining their physical and chemical properties and overall quality. However, quantification of the homogeneity of a variety of glasses is still a challenge for glass scientists and technologists. Here, we show a simple approach by which the homogeneity o...

  17. Recycling of Glass

    DEFF Research Database (Denmark)

    Christensen, Thomas Højlund; Damgaard, Anders

    2011-01-01

    Glass is used for many purposes, but in the waste system glass is predominantly found in terms of beverage and food containers with a relatively short lifetime before ending up in the waste. Furthermore there is a large amount of flat glass used in building materials which also ends up in the waste...

  18. Anti-inflammatory activity of cationic lipids.

    Science.gov (United States)

    Filion, M C; Phillips, N C

    1997-10-01

    1. The effect of liposome phospholipid composition has been assumed to be relatively unimportant because of the presumed inert nature of phospholipids. 2. We have previously shown that cationic liposome formulations used for gene therapy inhibit, through their cationic component, the synthesis by activated macrophages of the pro-inflammatory mediators nitric oxide (NO) and tumour necrosis factor-alpha (TNF-alpha). 3. In this study, we have evaluated the ability of different cationic lipids to reduce footpad inflammation induced by carrageenan and by sheep red blood cell challenge. 4. Parenteral (i.p. or s.c) or local injection of the positively charged lipids dimethyldioctadecylammomium bromide (DDAB), dioleyoltrimethylammonium propane (DOTAP), dimyristoyltrimethylammonium propane (DMTAP) or dimethylaminoethanecarbamoyl cholesterol (DC-Chol) significantly reduced the inflammation observed in both models in a dose-dependent manner (maximum inhibition: 70-95%). 5. Cationic lipids associated with dioleyol- or dipalmitoyl-phosphatidylethanolamine retained their anti-inflammatory activity while cationic lipids associated with dipalmitoylphosphatidylcholine (DPPC) or dimyristoylphosphatidylglycerol (DMPG) showed no anti-inflammatory activity, indicating that the release of cationic lipids into the macrophage cytoplasm is a necessary step for anti-inflammatory activity. The anti-inflammatory activity of cationic lipids was abrogated by the addition of dipalmitoylphosphatidylethanolamine-poly(ethylene)glycol-2000 (DPPE-PEG2000) which blocks the interaction of cationic lipids with macrophages. 6. Because of the significant role of protein kinase C (PKC) in the inflammatory process we have determined whether the cationic lipids used in this study inhibit PKC activity. The cationic lipids significantly inhibited the activity of PKC but not the activity of a non-related protein kinase, PKA. The synthesis of interleukin-6 (IL-6), which is not dependent on PKC activity for its

  19. Predicting liquid immiscibility in multicomponent nuclear waste glasses

    International Nuclear Information System (INIS)

    Taylor's model for predicting amorphous phase separation in complex, multicomponent systems has been applied to high-level (simulated) radioactive waste glasses at the US Department of Energy's Hanford site. Taylor's model is primarily based on additions of modifying cations to a Na2O-B2O3-SiO2 (NBS) submixture of the multicomponent glass. The position of the submixture relative to the miscibility dome defines the development probability of amorphous phase separation. Although prediction of amorphous phase separation in Hanford glasses (via experimental SEM/TEM analysis) is the primary thrust of this work; reported durability data is also provides limited insight into the composition/durability relationship. Using a modified model similar to Taylor's, the results indicate that immiscibility may be predicted for multicomponent waste glasses by the addition of Li2O to the ''alkali'' corner of the NBS submixture

  20. Afrikaans Syllabification Patterns

    Directory of Open Access Journals (Sweden)

    Tilla Fick

    2010-01-01

    Full Text Available In contrast to English, automatic hyphenation by computer of Afrikaans words is a problem that still needs to be addressed, since errors are still often encountered in printed text. An initial step in this task is the ability to automatically syllabify words. Since new words are created continuously by joining words, it is necessary to develop an “intelligent” technique for syllabification. As a first phase of the research, we consider only the orthographic information of words, and disregard both syntactic and morphological information. This approach allows us to use machine-learning techniques such as artificial neural networks and decision trees that are known for their pattern recognition abilities. Both these techniques are trained with isolated patterns consisting of input patterns and corresponding outputs (or targets that indicate whether the input pattern should be split at a certain position, or not. In the process of compiling a list of syllabified words from which to generate training data for the  syllabification problem, irregular patterns were identified. The same letter patterns are split differently in different words and complete words that are spelled identically are split differently due to meaning. We also identified irregularities in and between  the different dictionaries that we used. We examined the influence range of letters that are involved in irregularities. For example, for their in agter-ente and vaste-rente we have to consider three letters to the left of r to be certain where the hyphen should be inserted. The influence range of the k in verstek-waarde and kleinste-kwadrate is four to the left and three to the right. In an analysis of letter patterns in Afrikaans words we found that the letter e has the highest frequency overall (16,2% of all letters in the word list. The frequency of words starting with s is the highest, while the frequency of words ending with e is the highest. It is important to

  1. Method for in situ determination cation exchange capacities of subsurface formations

    International Nuclear Information System (INIS)

    A method is disclosed for the in situ examination of each subsurface formation penetrated by a borehole to ascertain the cation exchange capacity of such formations within a geological region. Natural γ ray logging is used to develop signals functionally related to the total γ radiation and to the potassium-40, uranium and thorium energy-band radiations. A first borehole is traversed by a potential γ ray spectrometer to provide selected measurements of natural γ radiation. Core samples are taken from the logged formation and laboratory tests performed to determine the cation exchange capacity thereof. The cation exchange capacities thus are developed then correlated with selected parameters provided by the γ ray spectrometer to establish functional relationships. Cation exchange capacities of formations in subsequent boreholes within the region are then determined in situ by use of the natural γ ray spectrometer and these established relationships. (author)

  2. Potential Modulated Intercalation of Alkali Cations into Metal Hexacyanoferrate Coated Electrodes

    International Nuclear Information System (INIS)

    Nickel hexacyanoferrate is a polynuclear inorganic ion intercalation material that loads (intercalates) and elutes (deintercalates) alkali cations from its structure when electrochemically reduced and oxidized, respectively. Nickel hexacyanoferrrate (NiHCF) is known to preferentially intercalate cesium over all other alkali cations, thus providing a basis for a separation scheme that can tackle DOE's radiocesium contamination problem. This program studied fundamental issues in alkalization intercalation and deintercalation in nickel hexacyanoferrate compounds, with the goal of (1) quantifying the ion exchange selectivity properties from cation mixtures, (2) enhancing ion exchange capacities, and (3) and understanding the electrochemically-switched ion exchange process (ESIX)

  3. Fluoride glass fiber optics

    CERN Document Server

    Aggarwal, Ishwar D

    1991-01-01

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

  4. Multiple Glass Ceilings

    OpenAIRE

    Russo, Giovanni; Hassink, Wolter

    2011-01-01

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

  5. Cryohydrocytosis: increased activity of cation carriers in red cells from a patient with a band 3 mutation

    DEFF Research Database (Denmark)

    Bogdanova, Anna; Goede, Jeroen S; Weiss, Erwin;

    2009-01-01

    blockers of anion and cation channels was assessed. RESULTS: In the cold, the cryohydrocytosis patient's erythrocytes swelled in KCl-containing, but not in NaCl-containing or KNO(3)-containing media indicating that volume changes were mediated by an anion-coupled cation transporter. In NaCl......-selective cation channel. The present study was performed to characterize so far unexplored ion transport pathways that may render erythrocytes of a single cryohydrocytosis patient cation-leaky. DESIGN AND METHODS: Cold-induced changes in cell volume were monitored using ektacytometry and density gradient...

  6. Altervalent cation-doped MCM-41 supported palladium catalysts and their catalytic properties

    OpenAIRE

    HAIHUI JIANG; LIGANG GAI; YAN TIAN

    2011-01-01

    Metal cation-doped MCM-41 (M-MCM-41, M = Al, Ce, Co, V or Zr) supported Pd catalysts (Pd/M-MCM-41) were prepared by a solution-based reduction method. The catalysts were characterized by X-ray diffraction (XRD) analysis, infrared spectroscopy (IR), scanning electron microscopy (SEM) and transmission electron microscopy (TEM), and further evaluated by selective hydrogenation of para-chloronitrobenzene (p-CNB) in anhydrous ethanol. The metal cation-containing Pd catalysts can efficiently enhanc...

  7. Adsorption equilibrium of fructose, glucose and sucrose for cationic resins in the sodium and potassium form

    OpenAIRE

    Nobre, Clarisse; Santos, M. J.; Dominguez, Ana; Torres, Duarte; Peres, António M.; Rocha, Isabel; Ferreira, Eugénio C.; Rodrigues, Lígia R.; Teixeira, José A.

    2009-01-01

    Separation of glucose from mixtures of fructose and sucrose in molasses is a major challenge in industrial sugar chromatographic separations. The efficiency of a chromatographic process is largely dependent on the adsorbent used. Sulfonated poly(styrene-co-divinylbenzene) (PS-DVB) ion exchange resins are the most frequently used for sugars separation, generally in a cationic form. The cation will complex with the hydroxyl group of the sugar leading to a selective adsorption accord...

  8. Final Report. Baseline LAW Glass Formulation Testing, VSL-03R3460-1, Rev. 0

    Energy Technology Data Exchange (ETDEWEB)

    Muller, Isabelle S. [The Catholic University of America, Washington, DC (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); Buechele, Andrew [The Catholic University of America, Washington, DC (United States); Rielley, Elizabeth [The Catholic University of America, Washington, DC (United States); Bazemore, Gina [The Catholic University of America, Washington, DC (United States); Cecil, Richard [The Catholic University of America, Washington, DC (United States); Hight, Kenneth [The Catholic University of America, Washington, DC (United States); Mooers, Cavin [The Catholic University of America, Washington, DC (United States); Lai, Shan-Tao T. [The Catholic University of America, Washington, DC (United States); Kruger, Albert A. [The Catholic University of America, Washington, DC (United States)

    2015-06-18

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

  9. Influence of processing conditions on the glass-crystal transition into borosilicate glasses

    International Nuclear Information System (INIS)

    The precipitation of a crystalline phase in glass is observed when one element exceeds its loading limit (i.e.: solubility limit). In this work we have studied the solubility of different actinides and surrogates (lanthanides and hafnium) in borosilicate glass used for the immobilization of the high-level nuclear waste (HLW glasses). The results obtained show an increase of the solubility limits of these elements with the processing temperature and the redox potential of the melt. The elements at the oxidation state (III) exhibit a higher solubility than the element at oxidation state (IV). In this framework, cerium is an interesting element because its oxidation state tunes from (IV) to (III) as a function of the processing conditions. It is shown that the solubility of cerium can be multiplied by a factor of 20 at 1100 C. degrees. In order to have a better understanding of the mechanisms that underline the evolution of the solubility, XAFS and NMR investigation has been undertaken. Trivalent elements present the characteristics of network-modified cations while tetravalent elements look like network-former cations

  10. Tripodal Receptors for Cation and Anion Sensors

    Directory of Open Access Journals (Sweden)

    David N. Reinhoudt

    2006-08-01

    Full Text Available This review discusses different types of artificial tripodal receptors for the selectiverecognition and sensing of cations and anions. Examples on the relationship between structure andselectivity towards cations and anions are described. Furthermore, their applications as potentiometricion sensing are emphasised, along with their potential applications in optical sensors or optodes.

  11. Advancements in Anion Exchange Membrane Cations

    Energy Technology Data Exchange (ETDEWEB)

    Sturgeon, Matthew R. [National Renewable Energy Lab. (NREL), Golden, CO (United States); Long, Hai [National Renewable Energy Lab. (NREL), Golden, CO (United States); Park, Andrew M. [National Renewable Energy Lab. (NREL), Golden, CO (United States); Pivovar, Bryan S. [National Renewable Energy Lab. (NREL), Golden, CO (United States)

    2015-10-15

    Anion-exchange membrane fuel cells (AME-FCs) are of increasingly popular interest as they enable the use of non-Pt fuel cell catalysts, the primary cost limitation of proton exchange membrane fuel cells. Benzyltrimethyl ammonium (BTMA) is the standard cation that has historically been utilized as the hydroxide conductor in AEMs. Herein we approach AEMs from two directions. First and foremost we study the stability of several different cations in a hydroxide solution at elevated temperatures. We specifically targeted BTMA and methoxy and nitro substituted BTMA. We've also studied the effects of adding an akyl spacer units between the ammonium cation and the phenyl group. In the second approach we use computational studies to predict stable ammonium cations, which are then synthesized and tested for stability. Our unique method to study cation stability in caustic conditions at elevated temperatures utilizes Teflon Parr reactors suitable for use under various temperatures and cation concentrations. NMR analysis was used to determine remaining cation concentrations at specific time points with GCMS analysis verifying product distribution. We then compare the experimental results with calculated modeling stabilities. Our studies show that the electron donating methoxy groups slightly increase stability (compared to that of BTMA), while the electron withdrawing nitro groups greatly decrease stability in base. These results give insight into possible linking strategies to be employed when tethering a BTMA like ammonium cation to a polymeric backbone; thus synthesizing an anion exchange membrane.

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

    International Nuclear Information System (INIS)

    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

  13. Structure of heavy cation molecules: from experiment to simulation

    Energy Technology Data Exchange (ETDEWEB)

    Den Auwer, C.; Fillaux, C.; Guilbaud, P.; Guillaumont, D.; Moisy, P. [CEA Marcoule DEN/DRCP/SCPS, 30207 Bagnols sur Ceze (France); Conradson, S.D. [Los Alamos National Laboratory, Los Alamos, NM 87545 (United States); Di Giandomenico, V.; Le Naour, C.; Simoni, E. [IPN Orsay, 91405 Orsay (France); Hennig, C. [Forschungszentrum Rossendorf, ROBL at ESRF, 38043 Grenoble (France)

    2008-07-01

    For industrial, environmental and public health purposes, actinide chemistry has been the subject of considerable efforts since the 50's. Aqueous redox chemistry, ionic selective recognition, uptake by specific biomolecules or compartments of the geosphere are some of the major fields of investigation. The physical-chemical properties of the actinide elements strongly depend on the 5f/6d electronic configuration. X-ray photons are an ideal spectroscopic tool for structure and bonding in actinide molecules. At high photon energies, actinide Extended X-ray Absorption Fine Structure (EXAFS) is a structural probe of the cation coordination sphere. Furthermore, coupling EXAFS with molecular dynamics or quantum chemical calculations leads to a better description of the 'cation in its close environment', like polyhedron, disorder, solvent effects etc.. (authors)

  14. Characterisation of heavy cations from dysprosium to plutonium

    International Nuclear Information System (INIS)

    For industrial, environmental and public health purposes, actinide chemistry has been the subject of considerable efforts since the 50's. Aqueous redox chemistry, ionic selective recognition, uptake by specific biomolecules or compartments of the geosphere are some of the major fields of investigation. The physical-chemical properties of the actinide and lanthanide elements strongly depend on the frontier orbital electronic configuration. This paper is divided in two parts. In the first one, coupling XAS with molecular dynamics allows to take into account solvent and disorder effects while fitting the EXAFS data of aqueous uranyl and dysprosium cations. In the second one EXAFS structural parameters of oxo-cations from protactinium to plutonium are compared to quantum chemical calculations. (authors)

  15. Parametric effects on glass reaction in the unsaturated test method

    International Nuclear Information System (INIS)

    The Unsaturated Test Method has been applied to study glass reaction under conditions that may be present at the potential Yucca Mountain site, currently under evaluation for storage of reprocessed high-level nuclear waste. The results from five separate sets of parametric experiments are presented wherein test parameters ranging from water contact volume to sensitization of metal in contact with the glass were examined. The most significant effect was observed when the volume of water, as controlled by the water inject volume and interval period, was such to allow exfoliation of reacted glass to occur. The extent of reaction was also influenced to a lesser extent by the degree of sensitization of the 304L stainless steel. For each experiment, the release of cations from the glass and alteration of the glass were examined. The major alteration product is a smectite clay that forms both from precipitation from solution and from in-situ alteration of the glass itself. It is this clay that undergoes exfoliation as water drips from the glass. A comparison is made between the results of the parametric experiments with those of static leach tests. In the static tests the rates of release become progressively reduced through 39 weeks while, in contrast, they remain relatively constant in the parametric experiments for at least 300 weeks. This differing behavior may be attributable to the dripping water environment where fresh water is periodically added and where evaporation can occur

  16. Parametric effects on glass reaction in the unsaturated test method

    Energy Technology Data Exchange (ETDEWEB)

    Woodland, A.B.; Bates, J.K.; Gerding, T.J.

    1991-12-01

    The Unsaturated Test Method has been applied to study glass reaction under conditions that may be present at the potential Yucca Mountain site, currently under evaluation for storage of reprocessed high-level nuclear waste. The results from five separate sets of parametric experiments are presented wherein test parameters ranging from water contact volume to sensitization of metal in contact with the glass were examined. The most significant effect was observed when the volume of water, as controlled by the water inject volume and interval period, was such to allow exfoliation of reacted glass to occur. The extent of reaction was also influenced to a lesser extent by the degree of sensitization of the 304L stainless steel. For each experiment, the release of cations from the glass and alteration of the glass were examined. The major alteration product is a smectite clay that forms both from precipitation from solution and from in-situ alteration of the glass itself. It is this clay that undergoes exfoliation as water drips from the glass. A comparison is made between the results of the parametric experiments with those of static leach tests. In the static tests the rates of release become progressively reduced through 39 weeks while, in contrast, they remain relatively constant in the parametric experiments for at least 300 weeks. This differing behavior may be attributable to the dripping water environment where fresh water is periodically added and where evaporation can occur.

  17. Formulation and Characterization of Waste Glasses with Varying Processing Temperature

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Dong-Sang; Schweiger, M. J.; Rodriguez, Carmen P.; Lepry, William C.; Lang, Jesse B.; Crum, Jarrod V.; Vienna, John D.; Johnson, Fabienne; Marra, James C.; Peeler, David K.

    2011-10-17

    This report documents the preliminary results of glass formulation and characterization accomplished within the finished scope of the EM-31 technology development tasks for WP-4 and WP-5, including WP-4.1.2: Glass Formulation for Next Generation Melter, WP-5.1.2.3: Systematic Glass Studies, and WP-5.1.2.4: Glass Formulation for Specific Wastes. This report also presents the suggested studies for eventual restart of these tasks. The initial glass formulation efforts for the cold crucible induction melter (CCIM), operating at {approx}1200 C, with selected HLW (AZ-101) and LAW (AN-105) successfully developed glasses with significant increase of waste loading compared to that is likely to be achieved based on expected reference WTP formulations. Three glasses formulated for AZ-101HLW and one glass for AN-105 LAW were selected for the initial CCIM demonstration melter tests. Melter tests were not performed within the finished scope of the WP-4.1.2 task. Glass formulations for CCIM were expanded to cover additional HLWs that have high potential to successfully demonstrate the unique advantages of the CCIM technologies based on projected composition of Hanford wastes. However, only the preliminary scoping tests were completed with selected wastes within the finished scope. Advanced glass formulations for the reference WTP melter, operating at {approx}1200 C, were initiated with selected specific wastes to determine the estimated maximum waste loading. The incomplete results from these initial formulation efforts are summarized. For systematic glass studies, a test matrix of 32 high-aluminum glasses was completed based on a new method developed in this study.

  18. The effects of composition on glass dissolution rates: The application of four models to a data base

    International Nuclear Information System (INIS)

    Four models have been applied to a data base to relate glass dissolution in distilled water to composition. The data base is used to compare the precisions obtained from the models in fitting actual data. The usefulness of the data base in formulating a model is also demonstrated. Two related models in which the composite or pH-adjusted free energy of hydration of the glass is the correlating parameter are compared with experimental data. In a structural model, the nonbridging oxygen content of the glasses is used to correlate glass dissolution rate to composition. In a model formulated for this report, the cation valence and the oxygen content of the glass are compared with observed dissolution rates. The models were applied to the 28-day normalized silica release at 900C for over 285 glass compositions with surface area to volume ratios of 10 m-1 (Materials Characterization Center MCC-1 glass durability test using distilled water). These glasses included the nonradioactive analogs of WV205 and SRL-165, as well as SRL-131, PNL 76-68, and a European glass, UK209. Predicted glass dissolution rates show similar fits to the data for all four models. The predictions of the models were also plotted for two subsets of the glasses: waste glasses and Savannah River Laboratory glasses. The model predictions fit the data for these groups much better than they fit the data for the entire set of glasses. 14 refs., 12 figs., 7 tabs

  19. Glass corrosion and irradiation damage performance

    International Nuclear Information System (INIS)

    Several options are under consideration for the disposition of surplus Pu resulting from weapons dismantling and site remediation. One option is immobilization of the Pu and scrap metal in class. followed by repository disposal. However, the final composition of class has not been selected, and the information regarding the long-term behavior of high Pu-loaded glasses under potential unsaturated repository conditions is limited. Additionally, several issues exist that are relevant to the feasibility of using glass as a waste form. In this paper, we discuss (1) the general behavior of Pu-loaded glasses when corroded by water; (2) the distribution of Pu, 235U, together with neutron absorbers during corrosion; (3) the effect of irradiation damage on glass corrosion behavior; and (4) the role of class modeling, in the calculation of long-term performance

  20. Cationic Bolaamphiphiles for Gene Delivery

    Science.gov (United States)

    Tan, Amelia Li Min; Lim, Alisa Xue Ling; Zhu, Yiting; Yang, Yi Yan; Khan, Majad

    2014-05-01

    Advances in medical research have shed light on the genetic cause of many human diseases. Gene therapy is a promising approach which can be used to deliver therapeutic genes to treat genetic diseases at its most fundamental level. In general, nonviral vectors are preferred due to reduced risk of immune response, but they are also commonly associated with low transfection efficiency and high cytotoxicity. In contrast to viral vectors, nonviral vectors do not have a natural mechanism to overcome extra- and intracellular barriers when delivering the therapeutic gene into cell. Hence, its design has been increasingly complex to meet challenges faced in targeting of, penetration of and expression in a specific host cell in achieving more satisfactory transfection efficiency. Flexibility in design of the vector is desirable, to enable a careful and controlled manipulation of its properties and functions. This can be met by the use of bolaamphiphile, a special class of lipid. Unlike conventional lipids, bolaamphiphiles can form asymmetric complexes with the therapeutic gene. The advantage of having an asymmetric complex lies in the different purposes served by the interior and exterior of the complex. More effective gene encapsulation within the interior of the complex can be achieved without triggering greater aggregation of serum proteins with the exterior, potentially overcoming one of the great hurdles faced by conventional single-head cationic lipids. In this review, we will look into the physiochemical considerations as well as the biological aspects of a bolaamphiphile-based gene delivery system.

  1. Viscosity and thermal expansion of rare earth containing soda-lime-silicate glass

    International Nuclear Information System (INIS)

    Viscosity, coefficient of thermal expansion, glass transition temperature and dilatometric softening temperature of soda-lime-silicate glass doped with rare earth oxides (La2O3, CeO2, Nd2O3) were investigated by the rotating crucible viscometer and dilatometry, the melting temperature and activation energy for viscous flow of the studied melt were derived on the basis of Arrhenius equation, in order to reveal the effects of rare earth elements on the behavior of soda-lime-silicate glass. The results show that introduction of rare earth oxides increases the coefficient of thermal expansion, decreases viscosity of soda-lime-silicate glass, and Nd2O3 is an exception in viscosity. The glass transition temperature, dilatometric softening temperature, melting temperature and activation energy for viscous flow of soda-lime-silicate glass doped with rare earth oxides increase with increasing cationic field strength of corresponding rare earth ions.

  2. New approach to produce special purpose visual aid glasses : a custom designed 5-axis mill

    OpenAIRE

    Fjelde, Bjørn; Stamsø, Alexander

    2011-01-01

    The thesis problem formulation is given by the company ProVista. ProVistas area of expertise is mainly the rehabilitation of visually impaired. This includes research, training of opticians and sale of supporting materials such as glasses with magni cation. The thesis problem is a part of the research to give their customers a better product with much shorter delivery time. Today the customers normally have to wait several weeks to get their visual aid glasses. The reason for this...

  3. Brine chemistry effects on the durability of a simulated nuclear waste glass

    International Nuclear Information System (INIS)

    The effects of various solution chemistry parameters on the alteration and leaching characteristics of a copper borosilicate simulated waste glass have been determined under hydrothermal conditions. Results are presented which demonstrate that leachant salinity, volume/glass surface area ratio, pH, cation content, and dissolved SiO2 concentration effects are important. A brief explanation of these results is given which is based on ion exchange and solution saturation equilibria

  4. Fixation by anion exchange of toxic materials in a glass matrix

    International Nuclear Information System (INIS)

    This invention relates to the immobilization of toxic, e.g., radioactive materials, internally in a silicate glass or silica gel matrix for extremely long periods of time. Toxic materials, such as radioactive wastes containing radioactive anions, and in some cases cations, which may be in the form of liquids, or solids dissolved or dispersed in liquids or gases, are internally incorporated into a glass matrix, having hydrous organofunctionalsiloxy groups, E.G., hydrous aminoalkylsiloxy or carboxyorganosiloxy, bonded to silicon atoms of said glass and/or hydrous polyvalent metals bonded to silicon atoms of said glass through divalent oxygen linkages or otherwise immobilized therein, by a process which involves the ion exchange of said toxic, radioactive anions with hydroxyl groups attached to said organofunctionalsiloxy groups or with hydroxyl groups attached to the hydrous polyvalent metal. Thereafter, the resulting glass now characterized by a distribution of internally bonded or immobilized, toxic, radioactive anions can be packaged in suitable containers, and disposed of as by burial, and/or they can be sintered to collapse the pores thereof prior to disposal or for producing useful radiation sources. The porous glass or a porous silica gel having said silicon-bonded organofunctionalsiloxy groups and/or said hydrous polyvalent metal oxy groups, the pores of said glass or silica gel remaining open and uncollapsed, can be used advantageously as a backfill for an underground radioactive waste burial site and as overpack in the waste disposal container. Also included is a novel method for bonding the polyvalent metal to the porous silica glass or gel by substituting the protons of the silicon-bonded hydroxyl groups thereof with an alkali metal or ammonium cation followed by displacement of said cation with the non-radioactive polyvalent metal cation

  5. Thermodynamics of Glass Melting

    Science.gov (United States)

    Conradt, Reinhard

    First, a model based on linear algebra is described by which the thermodynamic properties of industrial multi-component glasses and glass melts can be accurately predicted from their chemical composition. The model is applied to calculate the heat content of glass melts at high temperatures, the standard heat of formation of glasses from the elements, and the vapor pressures of individual oxides above the melt. An E-fiber glass composition is depicted as an example. Second, the role of individual raw materials in the melting process of E-glass is addressed, with a special focus on the decomposition kinetics and energetic situation of alkaline earth carriers. Finally, the heat of the batch-to-melt conversion is calculated. A simplified reaction path model comprising heat turnover, content of residual solid matter, and an approach to batch viscosity is outlined.

  6. A novel Ag+ cation sensor based on polyamidoamine dendrimer modified with 1,8-naphthalimide derivatives

    Science.gov (United States)

    Dodangeh, Mohammad; Gharanjig, Kamaladin; Arami, Mokhtar

    2016-02-01

    In this study, 4-amino-1,8-naphthalimide-conjugated polyamidoamine dendrimer was synthesized and characterized and its potentiality as a cation sensor was investigated. 4-Amino-1,8-naphthalic anhydride reacted with polyamidoamine dendrimer and the product was characterized using FTIR, 1H NMR, 13C NMR and melting point analysis method. The synthesized compound was applied to detect various cations in water media and N,N-dimethylformamide (DMF) via monitoring the quenching of the fluorescence intensity. Furthermore, various metal cations including Cu2 +, Ni2 +, Zn2 +, Pb2 +,Ca2 +, Ba2 +, Cd2 +, Hg2 +, Fe2 +, Fe3 + and Ag+ were tested. The complexes formed between the synthesized compound and metal cations in solution and their effects on Photoinduced Electron Transfer (PET) process were investigated regarding the potential application of the newly-synthesized dendrimer as a colorimetric and fluorescent sensor for such cations. The results clearly confirmed that the 1,8-naphthalimide groups surrounding the central dendrimer core showed strong green fluorescence emission at 553 nm. This effect considerably decreased with the introduction of all cations, except Ag+ where the fluorescence quenching effect was remarkable and more dominant. Therefore, it can be concluded that the synthesized dye has the potentiality of being a highly sensitive and selective fluorescence sensor for Ag+ cation.

  7. Modified cationic membranes for water purification, and their selective permeability

    Science.gov (United States)

    Mavrin, G. V.; Fasullin, D. D.; Melkolvan, R. G.

    2014-12-01

    Wastewater containing heavy metal ions pose a significant toxicological risk to aquatic ecosystems and humans. The common problem of modern engineering technology is the development of environmentally friendly systems with a closed-circuit and a minimum waste. The ion exchange membrane can significantly reduce the cost of wastewater treatment and provide a high degree of purification.

  8. Bioactivity of Sodium Free Fluoride Containing Glasses and Glass-Ceramics

    Directory of Open Access Journals (Sweden)

    Xiaojing Chen

    2014-07-01

    Full Text Available The bioactivity of a series of fluoride-containing sodium-free calcium and strontium phosphosilicate glasses has been tested in vitro. Glasses with high fluoride content were partially crystallised to apatite and other fluoride-containing phases. The bioactivity study was carried out in Tris and SBF buffers, and apatite formation was monitored by XRD, FTIR and solid state NMR. Ion release in solutions has been measured using ICP-OES and fluoride-ion selective electrode. The results show that glasses with low amounts of fluoride that were initially amorphous degraded rapidly in Tris buffer and formed apatite as early as 3 h after immersion. The apatite was identified as fluorapatite by 19F MAS-NMR after 6 h of immersion. Glass degradation and apatite formation was significantly slower in SBF solution compared to Tris. On immersion of the partially crystallised glasses, the fraction of apatite increased at 3 h compared to the amount of apatite prior to the treatment. Thus, partial crystallisation of the glasses has not affected bioactivity significantly. Fast dissolution of the amorphous phase was also indicated. There was no difference in kinetics between Tris and SBF studies when the glass was partially crystallised to apatite before immersion. Two different mechanisms of apatite formation for amorphous or partially crystallised glasses are discussed.

  9. Glass microspheres for brachytherapy

    International Nuclear Information System (INIS)

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

  10. Fractography of glass

    CERN Document Server

    Tressler, Richard

    1994-01-01

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

  11. Diamond turning of glass

    Energy Technology Data Exchange (ETDEWEB)

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

    1988-12-01

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

  12. Structure and aqueous reactivity of silicate glasses high-resolution nuclear magnetic resonance contribution

    International Nuclear Information System (INIS)

    This research aims at getting a better understanding of the relations which may exist between the chemical composition of the oxide silicate glasses, the structure and the aqueous reactivity. We study the cations present in most glasses, more particularly the radioactive waste glasses, and those which are more liable to bring information both about structure and reactivity. Among the experimental methods used, the nuclear magnetic resonance of multi-quantum magic-angle spinning (NMR MQ-MAS) has been carried out for the structural characterization of the pristine and altered glasses. In the first part, we discuss the possibility of deducting a type of information from a quantitative approach of the 23Na, 27Al and 17O NMR MQ-MAS. In the second part, we apply this method to glasses containing between two and six oxides. The vitreous compositions studied permit to focus our attention on the influence of sodium, aluminum and calcium on their local structural environment. We point out an evolution of the distributions of bond distances and angles in relation to the glass chemical composition. We show the strong potentiality of the 17O used to probe the pristine and altered glasses. The influence of the different cations studied on the rate of glass dissolution is debated from the alterations made on short periods. On the basis of all these data, we discuss the importance of the structural effect which may influence the kinetic phenomena of alteration. (author)

  13. Glass and vitrification

    International Nuclear Information System (INIS)

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

  14. Study of nuclear glasses alteration gel and synthesis of some model gels

    International Nuclear Information System (INIS)

    This work deals with the general problem of alteration of the reference nuclear glass R7T7. Attention is paid particularly to the altered layer formed at the glass surface during alteration process. In opposition to previous works, related essentially to glass dissolution kinetics based on chemical analyses of lixiviated elements, this thesis deals with alteration problems through structural studies of the reference glass and derived gel. This approach allows the determination of mechanisms for the gel formation and a better understanding of the behaviour of glasses towards lixiviation. Both approaches appeared complementary. Based on several spectroscopic techniques, this work showed the particular role of cations such as calcium, zirconium and iron. Studies of silica-based synthetic gels showed the synergic effect of formers cation and of one highly coordinated cation. The variation of the wavenumber related to Si-O-Si asymmetric stretching vibration can be correlated to O/Si ratio for ternary systems Si/Na/Zr. On the contrary, the Si losses of the materials depend on the number of non-bridging oxygen atoms. In the perspective of long-term behaviour, the alteration gel presents better characteristics than initial glass. It is therefore a highly stable material in static conditions. In the same way, synthetic gels are materials with very low solubilities (much lower than the alteration gel) and could be used as confining matrices. (authors). refs., 71 figs., 37 tabs

  15. Cationic ruthenium alkylidene catalysts bearing phosphine ligands

    OpenAIRE

    Endo, Koji; Grubbs, Robert H.

    2016-01-01

    The discovery of highly active catalysts and the success of ionic liquid immobilized systems have accelerated attention to a new class of cationic metathesis catalysts. We herein report the facile syntheses of cationic ruthenium catalysts bear-ing bulky phosphine ligands. Simple ligand exchange using silver(I) salts of non-coordinating or weakly coordinating anions pro-vided either PPh3 or chelating Ph2P(CH2)nPPh2 (n = 2 or 3) ligated cationic catalysts. The structures of these newly reported...

  16. Cation substitution in two coccolithophore species

    OpenAIRE

    Melteig, Hanna Elina

    2016-01-01

    Few things would be better than getting rid of CO2 while producing useful materials. Coccolithophores use CO2 in their photorespiration, in addition to using CO2 to produce coccoliths – small platelets made of calcite. Ca is a central cation in this process, and the goal of this project is to investigate to what extent other divalent cations can partially substitute for Ca and become part of the growing coccolith. The long term goal is to enable algae to harvest cations and produce mate...

  17. Bioactivity of Sodium Free Fluoride Containing Glasses and Glass-Ceramics

    OpenAIRE

    Xiaojing Chen; Xiaohui Chen; Brauer, Delia S.; Rory M. Wilson; Hill, Robert G.; Natalia Karpukhina

    2014-01-01

    The bioactivity of a series of fluoride-containing sodium-free calcium and strontium phosphosilicate glasses has been tested in vitro. Glasses with high fluoride content were partially crystallised to apatite and other fluoride-containing phases. The bioactivity study was carried out in Tris and SBF buffers, and apatite formation was monitored by XRD, FTIR and solid state NMR. Ion release in solutions has been measured using ICP-OES and fluoride-ion selective electrode. The results show that...

  18. The glass block site radionuclide migration study

    International Nuclear Information System (INIS)

    In 1960 25 nepheline syenite glass blocks containing 14 TBq of mixed fission products in 50 kg of glass were placed below the water table in a shallow sand aquifer at Chalk River Laboratories. Experimental studies undertaken at the site since 1960 have included detailed mapping of the plume of 90Sr in 1963, 1966 and 1971. Mathematical modeling studies have employed the radiostrontium plume data in determining the split between ion exchange and chemisorption of 90Sr, and in obtaining reaction rate data for chemisorption. The distribution of 137Cs on downgradient soils was mapped in 1963 and 1979. An extended plume of low-level 137Cs contamination observed in the 1979 study prompted an investigation of the role of particulate materials in radionuclide transport. IN 1983, large volume groundwater sampling and separation of cationic, anionic, and neutral dissolved species, as well as particulates, detected anionic and cationic dissolved europium isotopes (154 and 155), and again encountered particulate 137Cs. A variety of investigations of cesium and strontium sorption have provided a data base on sediment mineralogy, particle surface features, and information on sorption sites and processes. The year 1990 saw the inauguration of a three-year program to update investigations of radionuclide release, transport, and sorption at the glass block site. The first stage of the program has been a detailed definition and simulation of the hydrogeologic setting. Plume mapping and aqueous speciation studies are in progress. This paper summarizes past investigations, reviews the status of the current program, and discusses components of future studies, including investigations of sediment sorption mechanisms. (Author) (17 refs., 8 figs.)

  19. SLUDGE BATCH 7B GLASS VARIABILITY STUDY

    Energy Technology Data Exchange (ETDEWEB)

    Johnson, F.; Edwards, T.

    2011-10-25

    The Defense Waste Processing Facility (DWPF) is preparing to initiate processing Sludge Batch 7b (SB7b). In support of the upcoming processing, the Savannah River National Laboratory (SRNL) provided a recommendation to utilize Frits 418 with a 6% Na{sub 2}O addition (26 wt% Na{sub 2}O in sludge) and 702 with a 4% Na{sub 2}O addition (24 wt% Na{sub 2}O in sludge) to process SB7b. This recommendation was based on assessments of the compositional projections for SB7b available at the time from the Savannah River Remediation (SRR). To support qualification of SB7b, SRNL executed a variability study to assess the applicability of the current durability models for SB7b. The durability models were assessed over the expected composition range of SB7b, including potential caustic additions, combined with Frits 702 and 418 over a 32-40% waste loading (WL) range. Thirty four glasses were selected based on Frits 418 and 702 coupled with the sludge projections with an additional 4-6% Na{sub 2}O to reflect the potential caustic addition. Six of these glasses, based on average nominal sludge compositions including the appropriate caustic addition, were developed for both Frit 418 and Frit 702 at 32, 36 and 40% WL to provide coverage in the center of the anticipated SB7b glass region. All glasses were fabricated and characterized using chemical composition analysis, X-ray diffraction (XRD) and the Product Consistency Test (PCT). To comply with the DWPF Glass Product Control Program, a total of thirty four glasses were fabricated to assess the applicability of the current DWPF PCCS durability models. Based on the measured PCT response, all of the glasses were acceptable with respect to the Environmental Assessment (EA) benchmark glass regardless of thermal history. The NL[B] values of the SB7b variability study glasses were less than 1.99 g/L as compared to 16.695 g/L for EA. A small number of the D-optimally selected 'outer layer' extreme vertices (EV) glasses were not

  20. Structural and crystallisation study of a rare earth alumino borosilicate glass designed for nuclear waste confinement

    International Nuclear Information System (INIS)

    This work is devoted to the study of a rare earth alumino borosilicate glass, which molar composition is 61,81 SiO2 - 3,05 Al2O3 - 8,94 B2O3 - 14,41 Na2O - 6,33 CaO - 1,90 ZrO2 - 3,56 Nd2O3, and envisaged for the immobilization of nuclear wastes originating from the reprocessing of high discharge burn up spent fuel. From a structural viewpoint, we investigated the role of the modifier cations on the arrangement of the glass network through different modifications of the glass composition: variation of the Na/Ca ratio and modification of the nature of the alkali and alkaline earth cations. The NMR and Raman spectroscopic techniques were useful to determine the distribution of modifier cations among the glass network and also to cast light on the competition phenomena occurring between alkali and alkaline earth cations for charge compensation of [AlO4]- and [BO4]- species. The neodymium local environment could be probed by optical absorption and EXAFS spectroscopies which enabled to better understand the insertion mode of Nd3+ ions among the silicate domains of the glass network. Concerning the crystallization behavior we were interested in how the glass composition may influence the crystallization processes and especially the formation of the apatite phase of composition Ca2Nd8(SiO4)6O2. In particular, this work underlined the important role of both alkaline earth and rare earth cations on the crystallization of the apatite phase. (author)

  1. Modelling of cation concentrations in the outflow of NaNO3 percolation experiments through Boom Clay cores

    International Nuclear Information System (INIS)

    A laboratory percolation experiment was performed to study the effect of a NaNO3 plume on the Boom Clay. In this experiment, Boom Clay cores were consecutively percolated with Boom Clay pore water and Boom Clay pore water to which NaNO3 was added. The concentration of NaNO3 in the pore water was increased stepwise (0.1, 0.5, and 1 M NaNO3). The concentrations of Na, K, Ca, Mg and Sr in the eluted water were measured. After every switch of the NaNO3 concentration, the concentration profiles of K, Ca, Mg, and Sr showed a sharp rise, followed by a slow decrease. It was hypothesised that the cation elution curves are mainly determined by cation exchange processes. Reactive coupled transport modelling with the PHREEQC-2 code was used to describe the experimentally observed elution curves for the cations. Solute transport and water-clay interaction mechanisms, namely cation exchange, were accounted for in the model. Cation exchange parameters (cation exchange capacity and selectivity coefficients) previously determined on non-perturbed Boom Clay (De Craen et al., 2004) were used. A sensitivity analysis was performed to assess the influence of these parameter values on the goodness of the model to describe the experimental data. The model could fairly well describe the experimentally observed cation concentrations in the eluted water, confirming that cation exchange is indeed the dominant mechanism regulating the cation elution in the percolation experiments. (authors)

  2. Cationization of heparin for film applications

    Czech Academy of Sciences Publication Activity Database

    Šimkovic, I.; Mendichi, R.; Kelnar, Ivan; Filip, J.; Hricovíni, M.

    2015-01-01

    Roč. 115, 22 January (2015), s. 551-558. ISSN 0144-8617 Institutional support: RVO:61389013 Keywords : heparin * cationization * NMR Subject RIV: CD - Macromolecular Chemistry Impact factor: 4.074, year: 2014

  3. Cycloaliphatic epoxide resins for cationic UV - cure

    International Nuclear Information System (INIS)

    This paper introduces the cyclo - aliphatic epoxide resins used for the various applications of radiation curing and their comparison with acrylate chemistry. Radiation curable coatings and inks are pre - dominantly based on acrylate chemistry but over the last few years, cationic chemistry has emerged successfully with the unique properties inherent with cyclo - aliphatic epoxide ring structures. Wide variety of cationic resins and diluents, the formulation techniques to achieve the desired properties greatly contributes to the advancement of UV - curing technology

  4. Test procedure for cation exchange chromatography

    International Nuclear Information System (INIS)

    The purpose of this test plan is to demonstrate the synthesis of inorganic antimonate ion exchangers and compare their performance against the standard organic cation exchangers. Of particular interest is the degradation rate of both inorganic and organic cation exchangers. This degradation rate will be tracked by determining the ion exchange capacity and thermal stability as a function of time, radiation dose, and chemical reaction

  5. Silica-based cationic bilayers as immunoadjuvants

    OpenAIRE

    Carmona-Ribeiro Ana M; da Costa Maria; Faquim-Mauro Eliana; Santana Mariana RA; Lincopan Nilton

    2009-01-01

    Abstract Background Silica particles cationized by dioctadecyldimethylammonium bromide (DODAB) bilayer were previously described. This work shows the efficiency of these particulates for antigen adsorption and presentation to the immune system and proves the concept that silica-based cationic bilayers exhibit better performance than alum regarding colloid stability and cellular immune responses for vaccine design. Results Firstly, the silica/DODAB assembly was characterized at 1 mM NaCl, pH 6...

  6. Cations and activated sludge floc structure

    OpenAIRE

    Park, Chul

    2002-01-01

    This research was designed to investigate the effect of cations on activated sludge characteristics and also to determine their influence on digestion performance. For this purpose, cations in solution and in floc were evaluated along with various activated sludge characteristics and the collected waste activated sludge underwent both anaerobic and aerobic digestion. It was found that large amounts of biopolymer (protein + polysaccharide) remained in the effluent of WWTP that received high in...

  7. Formation of Elemental Distribution in Glasses by Femtosecond Laser Irradiation

    International Nuclear Information System (INIS)

    We report on the fabrication of optical waveguides and the precipitation of nonlinear optical crystals inside glass caused by local element migration with high-repetition femtosecond laser irradiation. Elements that contribute to the high refractive index migrated to the center of the focal region because of the femtosecond laser irradiation in phosphate and borate glasses. Based on this result, we successfully wrote optical waveguides in these glasses, where element distributions were continuously induced along a path traversed by the focal point. Furthermore, we succeeded in space-selective precipitation of nonlinear optical crystals such as β-BBO inside glass by controlling the thermophysical property (crystallization temperature).

  8. Study on the protection of Er-doped phosphate glass waveguide surface in ion-exchange processing

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    A novel method, sputtering K9 glass film, is proposed to solve the surface corrosion of Er-doped phosphate glass during ion-exchange processing for optical waveguide fabrication. The corrosion causes are analyzed to be the intrinsically weak stabilization of phosphate glass structure, hydrophile and weakly acidic property of phosphate radical. Experimental results show that the K9 glass film could not only protect the Er-doped phosphate glass surface from being corroded but also give no influence on the waveguide fabrication. The effect of thickness of K9 glass film on the optical property of waveguide is also investigated and the op- timal thickness is found to be 60―80 nm. It provides a good base for further fabri- cation of active phosphate glass optical waveguide devices.

  9. Getting Started with Glass

    Science.gov (United States)

    White, Heather

    2007-01-01

    The metamorphosis of glass when heated is a magical process to students, yet teachers are often reluctant to try it in class. The biggest challenge in working with glass in the classroom is to simplify procedures just enough to ensure student success while maintaining strict safety practices so no students are injured. Project concepts and safety…

  10. Electric glass capturing markets

    Energy Technology Data Exchange (ETDEWEB)

    Wikman, K.; Wikstroem, T.

    1996-11-01

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

  11. lead glass brick

    CERN Multimedia

    As well as accelerators to boost particles up to high energy, physicists need detectors to see what happens when those particles collide. This lead glass block is part of a CERN detector called OPAL. OPAL uses some 12 000 blocks of glass like this to measure particle energies.

  12. Glasses for Children

    Science.gov (United States)

    ... difficulties in the classroom. Most children who have difficulty with reading do not need glasses, but this can be ... have had cataract surgery usually need bifocals or reading glasses. Will ... normal vision development can be adversely affected. What are some things ...

  13. Spin glasses and biology

    CERN Document Server

    Stein, David

    1992-01-01

    This volume is an introduction to the application of techniques developed for the study of disordered systems to problems which arise in biology. Topics presented include neural networks, adaptation and evolution, maturation of the immune response, and protein dynamics and folding. This book will appeal to students and researchers interested in statistical and condensed matter physics, glasses and spin glasses, and biophysics.

  14. Biocorrosion of Archaeological Glass

    OpenAIRE

    Shelley, William L.

    2016-01-01

    This research investigates the physical manifestation and chemical mechanisms andprocesses of biologically-induced corrosion of archaeological glass. Archaeological glasssamples from Greece and Cyprus suspected to have undergone biocorrosion wereanalyzed to characterize the composition and surface topography and to determine thedifference in the chemistry and microstructure between the glass surface and the bulk.Microscopic and analytical techniques employed include digital microscopy, polari...

  15. Glass Sword of Damocles

    Institute of Scientific and Technical Information of China (English)

    2011-01-01

    A string of accidents draws attention to the safety of the gleaming glass-walled skyscrapers, now common in China’s major cities On July 8, as 19-year-old Zhu Yiyi was walking past a 23-story building in Hangzhou, east China’s Zhejiang Province, shards of glass falling

  16. Oxide glasses free of classical network formers

    International Nuclear Information System (INIS)

    The kinetic theory of glass formation (Uhlmann 1972, Uhlmann ampersand Yinnon 1983) relegates the classical network theory to just one specific, though large and important, region of potential glass compositions. Accordingly, a large number of interesting oxide systems free of the network forming oxides of SiO2, GeO2, P2O5, B2O3, can be found and exploited for particular applications, e.g. attractive compromises between optical performance and stability. Identification and characterizations of glasses in such systems are briefly reviewed in what follows, stressing most recent developments, as well as less accessible reports. Cations of lower field strength not favoring oxide network formation will typically have absorption edges at desirable e.g. lower ir frequencies (higher wavelengths) in fibers guiding conventional laser frequencies. When higher linear and nonlinear refractivity is called for, optimization depends on a compromise between the positive effect of a high atomic number and low polarizability of oxygen with the negative effect of higher valency causing dilution with oxygen. Moreover, some systems free of classical network formers exhibit low scattering

  17. Method for making glass

    International Nuclear Information System (INIS)

    A method for making better quality molten (borosilicate and other) glass in a glass melter, the glass having the desired viscosity and, preferably, also the desired resistivity so that the glass melt can be established effectively and the product of the glass melter will have the desired level of quality. The method includes the adjustment of the composition of the a ass constituents that are fed into the melterin accordance with certain correlations that reliably predict the viscosity and resistivity from the melter temperature and the melt composition, then heating the ingredients to the melter's operating temperature until they melt and homogenize. The equations include the calculation of a ''non-bridging oxygen'' term from the numbers of moles of the various ingredients, and then the determination of the viscosity and resistivity from the operating temperature of the melter and the non-bridging oxygen term

  18. Infrared Photodissociation Spectroscopy of Metal Oxide Carbonyl Cations.

    Science.gov (United States)

    Brathwaite, Antonio D.; Duncan, Michael A.

    2013-06-01

    Mass selected metal oxide-carbonyl cations of the form MO_{m}(CO)_{n}^{+} are studied via infrared laser photodissociation spectroscopy, in the 600-2300cm^{1} region. Insight into the structure and bonding of these complexes is obtained from the number of infrared active bands, their relative intensities and their frequency positions. Density functional theory calculations are carried out in support of the experimental data. Insight into the bonding of CO ligands to metal oxides is obtained and the effect of oxidation on the carbonyl stretching frequency is revealed.

  19. A NEW METHOD TO SYNTHESIZE THE CATIONIC GRAFT STARCH

    Institute of Scientific and Technical Information of China (English)

    Lin Li; Bingyue Liu; Yafeng Cao

    2004-01-01

    The cationic graft copolymer was synthesized by reversed phase emulsion copolymerization of starch with diallydimethyl ammoniumlchlorid (DADMAC)and acrylamide (AM). The copolymerization was carried out using (NH4)2S2O8-NH2CONH2 redox as initiator and selecting Span-20 as emulsifier. The effects of emulsifier content in oil phase, volume ratio of oil to water, initiator concentration and mole ratio of DADMAC to AM on the graft copolymerization were discussed. The optimum condition of synthetics was found with the orthogonal test method.

  20. Commercial Ion Exchange Resin Vitrification in Borosilicate Glass

    International Nuclear Information System (INIS)

    Bench-scale studies were performed to determine the feasibility of vitrification treatment of six resins representative of those used in the commercial nuclear industry. Each resin was successfully immobilized using the same proprietary borosilicate glass formulation. Waste loadings varied from 38 to 70 g of resin/100 g of glass produced depending on the particular resin, with volume reductions of 28 percent to 68 percent. The bench-scale results were used to perform a melter demonstration with one of the resins at the Clemson Environmental Technologies Laboratory (CETL). The resin used was a weakly acidic meth acrylic cation exchange resin. The vitrification process utilized represented a approximately 64 percent volume reduction. Glass characterization, radionuclide retention, offgas analyses, and system compatibility results will be discussed in this paper

  1. Divalent cation shrinks DNA but inhibits its compaction with trivalent cation

    Science.gov (United States)

    Tongu, Chika; Kenmotsu, Takahiro; Yoshikawa, Yuko; Zinchenko, Anatoly; Chen, Ning; Yoshikawa, Kenichi

    2016-05-01

    Our observation reveals the effects of divalent and trivalent cations on the higher-order structure of giant DNA (T4 DNA 166 kbp) by fluorescence microscopy. It was found that divalent cations, Mg(2+) and Ca(2+), inhibit DNA compaction induced by a trivalent cation, spermidine (SPD(3+)). On the other hand, in the absence of SPD(3+), divalent cations cause the shrinkage of DNA. As the control experiment, we have confirmed the minimum effect of monovalent cation, Na(+) on the DNA higher-order structure. We interpret the competition between 2+ and 3+ cations in terms of the change in the translational entropy of the counterions. For the compaction with SPD(3+), we consider the increase in translational entropy due to the ion-exchange of the intrinsic monovalent cations condensing on a highly charged polyelectrolyte, double-stranded DNA, by the 3+ cations. In contrast, the presence of 2+ cation decreases the gain of entropy contribution by the ion-exchange between monovalent and 3+ ions.

  2. Rare earth impact on glass structure and alteration kinetics

    International Nuclear Information System (INIS)

    This work is related to the question of the geological deep repository of high-level waste glass. These wastes include fission products and minor actinides, elements which can be simulated by rare earths. As new glass compositions could enable increased rare earth concentrations, it is crucial to know and understand rare earth impact on glass structure on the one hand, and on glass alteration kinetics or their incorporation into an altered layer. This work studied simplified borosilicate glasses in order to limit synergetic effects between rare earths and other elements. Various complementary techniques were used to characterize pristine and altered glasses (solid-high resolution NMR, Raman spectroscopy, fluorescence, SIMS, SAXS). Firstly, the structural role of a rare earth is discussed and is compared to a calcium cation. The local environment of rare earths is also probed. Secondly, rare earth (nature and concentration) impact on several alteration regimes was studied (initial rate, rate drop). Then, after alteration, rare earth elements being retained within the altered layer, the structural impact of rare earth elements (and their local environment) in this alteration layer was also investigated. (author)

  3. Defense HLW Glass Degradation Model

    International Nuclear Information System (INIS)

    The purpose of this report is to document the development of a model for calculating the release rate for radionuclides and other key elements from high-level radioactive waste (HLW) glasses under exposure conditions relevant to the performance of the repository. Several glass compositions are planned for the repository, some of which have yet to be identified (i.e., glasses from Hanford and Idaho National Engineering and Environmental Laboratory). The mechanism for glass dissolution is the same for these glasses and the glasses yet to be developed for the disposal of DOE wastes. All of these glasses will be of a quality consistent with the glasses used to develop this report

  4. Defense HLW Glass Degradation Model

    Energy Technology Data Exchange (ETDEWEB)

    D. Strachan

    2004-10-20

    The purpose of this report is to document the development of a model for calculating the release rate for radionuclides and other key elements from high-level radioactive waste (HLW) glasses under exposure conditions relevant to the performance of the repository. Several glass compositions are planned for the repository, some of which have yet to be identified (i.e., glasses from Hanford and Idaho National Engineering and Environmental Laboratory). The mechanism for glass dissolution is the same for these glasses and the glasses yet to be developed for the disposal of DOE wastes. All of these glasses will be of a quality consistent with the glasses used to develop this report.

  5. Composition-structure-property relation of oxide glasses

    DEFF Research Database (Denmark)

    Hermansen, Christian

    also increases such properties. Yet, these rules are not strictly followed even for the simplest binary oxide glasses, such as alkali silicates, borates and phosphates. In this thesis it is argued that the missing link between composition and properties is the glass structure. Structural models are......The composition of glass can be varied continuously within their glass-forming regions. This compositional flexibility makes it possible to tailor the properties of a glass for a variety of specific uses. In the industry such tailoring is done on a trial-and-error basis with only the intuition of a...... proposed based on topological selection rules and experimentally verified. The relation between structure and properties is evaluated using topological constraint theory, which in its essence is a theory that quantifies the two intuitions of the glass scientist. The end result is a quantitative model...

  6. CO 2 adsorption in mono-, di- and trivalent cation-exchanged metal-organic frameworks: A molecular simulation study

    KAUST Repository

    Chen, Yifei

    2012-02-28

    A molecular simulation study is reported for CO 2 adsorption in rho zeolite-like metal-organic framework (rho-ZMOF) exchanged with a series of cations (Na +, K +, Rb +, Cs +, Mg 2+, Ca 2+, and Al 3+). The isosteric heat and Henry\\'s constant at infinite dilution increase monotonically with increasing charge-to-diameter ratio of cation (Cs + < Rb + < K + < Na + < Ca 2+ < Mg 2+ < Al 3+). At low pressures, cations act as preferential adsorption sites for CO 2 and the capacity follows the charge-to-diameter ratio. However, the free volume of framework becomes predominant with increasing pressure and Mg-rho-ZMOF appears to possess the highest saturation capacity. The equilibrium locations of cations are observed to shift slightly upon CO 2 adsorption. Furthermore, the adsorption selectivity of CO 2/H 2 mixture increases as Cs + < Rb + < K + < Na + < Ca 2+ < Mg 2+ ≈ Al 3+. At ambient conditions, the selectivity is in the range of 800-3000 and significantly higher than in other nanoporous materials. In the presence of 0.1% H 2O, the selectivity decreases drastically because of the competitive adsorption between H 2O and CO 2, and shows a similar value in all of the cation-exchanged rho-ZMOFs. This simulation study provides microscopic insight into the important role of cations in governing gas adsorption and separation, and suggests that the performance of ionic rho-ZMOF can be tailored by cations. © 2012 American Chemical Society.

  7. Lead determination in glasses by laser-induced breakdown spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Carmona, N. [Centro Nacional de Investigaciones Metalurgicas, CENIM-CSIC, Gregorio del Amo 8, 28040 Madrid (Spain)], E-mail: ncarmona@cenim.csic.es; Oujja, M.; Gaspard, S. [Instituto de Quimica Fisica Rocasolano, CSIC. Serrano 119, 28006 Madrid (Spain); Garcia-Heras, M. [Centro Nacional de Investigaciones Metalurgicas, CENIM-CSIC, Gregorio del Amo 8, 28040 Madrid (Spain); Instituto de Historia, CSIC. Serrano 13, 28001 Madrid (Spain); Villegas, M.A. [Centro Nacional de Investigaciones Metalurgicas, CENIM-CSIC, Gregorio del Amo 8, 28040 Madrid (Spain); Castillejo, M. [Instituto de Quimica Fisica Rocasolano, CSIC. Serrano 119, 28006 Madrid (Spain)], E-mail: marta.castillejo@iqfr.csic.es

    2007-02-15

    Laser-induced breakdown spectroscopy (LIBS) has been used to determine the lead content of different types of lead silicate glasses commercially designed as sonorous glass (which contain {approx} 10 wt.% PbO); crystal glass (with at least 24 wt.% PbO) and superior crystal glass (with at least 30 wt.% PbO). Seven different types of glass samples were selected, including historic-original, model and commercially available. The selected samples were artificially weathered under neutral, acid and alkaline attack. Analysis by LIBS was carried out in vacuum under excitation at 266 nm and results were compared with those obtained by conventional techniques used for glass characterization. Composition of the bulk glasses was analyzed by XRF (X-ray fluorescence) and the corroded surfaces were characterized by SEM/EDX (scanning electron microscopy/energy dispersive X-ray microanalysis). A linear correlation was obtained between the intensity of selected Pb lines in the LIB spectra and the PbO content. The effect of corrosion could be characterized by comparing successive LIB spectra recorded on the same area; acid attack resulted in a decrease of PbO, CaO and Na{sub 2}O content in the surface with respect to the bulk of the sample, while minor changes in the composition were noticed under alkaline attack. These results show LIBS as a useful technique to classify the different types of lead glasses by their lead content and to determine and asses the degree and type of corrosion.

  8. Influence of strontium and the importance of glass chemistry and structure when designing bioactive glasses for bone regeneration.

    Science.gov (United States)

    O'Donnell, M D; Hill, R G

    2010-07-01

    The purpose of this article is to highlight some recent in vitro and in vivo studies of bioactive glasses containing strontium and to review selected literature on the in vitro and in vivo behaviour of bioactive glasses to relate this to the structure of the glass. The strontium-glass studies were performed well scientifically, but the results and conclusions could be misleading in terms of the effect of strontium, or more broadly glass chemistry, on the bioactivity and in vivo behaviour of bioactive glasses due to substitutions made on a weight basis. When strontium is substituted by weight for a lighter element such as calcium this will have a significant effect on structure and properties in particular biological response. PMID:20079468

  9. Accelerators for forming cationic technetium complexes useful as radiodiagnostic images

    International Nuclear Information System (INIS)

    This invention relates to compositions for making cationic radiodiagnostic agents and, in particular, to accelerator compounds for labelling such cationic radiodiagnostic agents, kits for preparing such 99mTc-labelled cationic radiodiagnostic agents with technetium, and methods for labelling such cationic radiodiagnostic agents with technetium

  10. Metallic glass composition. [That does not embrittle upon annealing

    Science.gov (United States)

    Kroeger, D.M.; Koch, C.C.

    1984-09-14

    This patent pertains to a metallic glass alloy that is either iron-based or nickel-based or based on a mixture of iron and nickel, containing lesser amounts of elements selected from the group boron, silicon, carbon and phosphorous to which is added an amount of a ductility-enhancing element selected from the group cerium, lanthanum, praseodymium and neodymium sufficient to increase ductility of the metallic glass upon annealing.

  11. Effect of different glasses in glass bonded zeolite

    International Nuclear Information System (INIS)

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

  12. New fluoroindate glass compositions

    OpenAIRE

    Messaddeq, Younes; Delben, A. A. S. T.; Boscolo, M.; Michel A. Aegerter; Soufiane, A.; Poulain, M.

    1993-01-01

    Fluoroindate glasses are potential new materials for the fabrication of IR fibers with extended spectral range. InF3SrF2BaF2ZnF2X glass compositions, where X = PbF2, CdF2, NaF and CaF2, have been prepared in a glove box using a conventional method and their phase diagrams have been determined. The addition of small quantities of GdF3 improves the stability of these compositions. Optical and thermal properties of these glasses are reported. © 1993.

  13. Relaxation of Anisotropic Glasses

    DEFF Research Database (Denmark)

    Deubener, Joachim; Martin, Birgit; Wondraczek, Lothar; Yue, Yuanzheng

    2004-01-01

    Anisotropic glasses are obtained from uniaxial compressing and pulling of glass forming liquids above the transition temperature range. To freeze-in, at least partly the structural state of the flowing melt, cylindrical samples were subjected to a controlled cooling process under constant load...... differential scanning calorimetry (DSC) and dilatometry. The energy release and expansion-shrinkage behaviour of the glasses are investigated as a function of the applied deformation stress. Structural origins of the frozen-in birefringence induced by viscous flow are discussed and correlation between the...

  14. Infrared spectroscopy of the methanol cation and its methylene-oxonium isomer

    International Nuclear Information System (INIS)

    The carbenium ion with nominal formula [C,H4,O]+ is produced from methanol or ethylene glycol in a pulsed-discharge supersonic expansion source. The ion is mass selected, and its infrared spectrum is measured from 2000 to 4000 cm−1 using laser photodissociation spectroscopy and the method of rare gas atom tagging. Computational chemistry predicts two isomers, the methanol and methylene-oxonium cations. Predicted vibrational spectra based on scaled harmonic and reduced dimensional treatments are compared to the experimental spectra. The methanol cation is the only isomer produced when methanol is used as a precursor. When ethylene glycol is used as the precursor, methylene-oxonium is produced in addition to the methanol cation. Theoretical results at the CCSD(T)/cc-pVTZ level show that methylene-oxonium is lower in energy than methanol cation by 6.4 kcal/mol, and is in fact the global minimum isomer on the [C,H4,O]+ potential surface. Methanol cation is trapped behind an isomerization barrier in our source, providing a convenient method to produce and characterize this transient species. Analysis of the spectrum of the methanol cation provides evidence for strong CH stretch vibration/torsion coupling in this molecular ion

  15. Infrared spectroscopy of the methanol cation and its methylene-oxonium isomer

    Energy Technology Data Exchange (ETDEWEB)

    Mosley, J. D.; Young, J. W.; Duncan, M. A., E-mail: mccoy@chemistry.ohio-state.edu, E-mail: maduncan@uga.edu [Department of Chemistry, University of Georgia, Athens, Georgia 30602 (United States); Huang, M.; McCoy, A. B., E-mail: mccoy@chemistry.ohio-state.edu, E-mail: maduncan@uga.edu [Department of Chemistry and Biochemistry, The Ohio State University, Columbus, Ohio 43210 (United States)

    2015-03-21

    The carbenium ion with nominal formula [C,H{sub 4},O]{sup +} is produced from methanol or ethylene glycol in a pulsed-discharge supersonic expansion source. The ion is mass selected, and its infrared spectrum is measured from 2000 to 4000 cm{sup −1} using laser photodissociation spectroscopy and the method of rare gas atom tagging. Computational chemistry predicts two isomers, the methanol and methylene-oxonium cations. Predicted vibrational spectra based on scaled harmonic and reduced dimensional treatments are compared to the experimental spectra. The methanol cation is the only isomer produced when methanol is used as a precursor. When ethylene glycol is used as the precursor, methylene-oxonium is produced in addition to the methanol cation. Theoretical results at the CCSD(T)/cc-pVTZ level show that methylene-oxonium is lower in energy than methanol cation by 6.4 kcal/mol, and is in fact the global minimum isomer on the [C,H{sub 4},O]{sup +} potential surface. Methanol cation is trapped behind an isomerization barrier in our source, providing a convenient method to produce and characterize this transient species. Analysis of the spectrum of the methanol cation provides evidence for strong CH stretch vibration/torsion coupling in this molecular ion.

  16. Infrared spectroscopy of the methanol cation and its methylene-oxonium isomer

    Science.gov (United States)

    Mosley, J. D.; Young, J. W.; Huang, M.; McCoy, A. B.; Duncan, M. A.

    2015-03-01

    The carbenium ion with nominal formula [C,H4,O]+ is produced from methanol or ethylene glycol in a pulsed-discharge supersonic expansion source. The ion is mass selected, and its infrared spectrum is measured from 2000 to 4000 cm-1 using laser photodissociation spectroscopy and the method of rare gas atom tagging. Computational chemistry predicts two isomers, the methanol and methylene-oxonium cations. Predicted vibrational spectra based on scaled harmonic and reduced dimensional treatments are compared to the experimental spectra. The methanol cation is the only isomer produced when methanol is used as a precursor. When ethylene glycol is used as the precursor, methylene-oxonium is produced in addition to the methanol cation. Theoretical results at the CCSD(T)/cc-pVTZ level show that methylene-oxonium is lower in energy than methanol cation by 6.4 kcal/mol, and is in fact the global minimum isomer on the [C,H4,O]+ potential surface. Methanol cation is trapped behind an isomerization barrier in our source, providing a convenient method to produce and characterize this transient species. Analysis of the spectrum of the methanol cation provides evidence for strong CH stretch vibration/torsion coupling in this molecular ion.

  17. Computer simulation study of low-energy excitations of silicate glasses

    International Nuclear Information System (INIS)

    Ten silicate and aluminosilicate glasses with different number densities and connectivities were studied by molecular dynamics simulation using the computer program DLPOLY. The radial distribution functions, phonon densities of states and flexibilities of the glass networks were determined, and compared with those determined for silica. The large-scale flexibility of silica was found to be similar to that of some of the glasses studied in this work, particularly in relation to rigid-unit-mode-type motions. The degree of localization of vibrations in fully networked glasses was found to be similar to that in silica, but the vibrations in glasses containing non-bridging oxygen atoms were found to be more localized. This is thought to be due to clustering of alkali cations, which in turn necessarily produces clusters of tetrahedra. (author)

  18. Exchangeable cations-mediated photodegradation of polycyclic aromatic hydrocarbons (PAHs) on smectite surface under visible light

    International Nuclear Information System (INIS)

    Graphical abstract: Roles of exchangeable cations in PAHs photodegradation on clay surafces under visible light. - Highlights: • Photolysis rate are strongly dependent on the type of cations on clay surface. • The strength of “cation–π” interactions governs the photodegradation rate of PAHs. • Several exchangeable cations could cause a shift in the absorption spectrum of PAHs. • Exchangeable cations influence the type and amount of reactive intermediates. - Abstract: Clay minerals saturated with different exchangeable cations are expected to play various roles in photodegradation of polycyclic aromatic hydrocarbons (PAHs) via direct and/or indirect pathways on clay surfaces. In the present study, anthracene and phenanthrene were selected as molecule probes to investigate the roles of exchangeable cations on their photodegradation under visible light irradiation. For five types of cation-modified smectite clays, the photodegradation rate of anthracene and phenanthrene follows the order: Fe3+ > Al3+ > Cu2+ >> Ca2+ > K+ > Na+, which is consistent with the binding energy of cation–π interactions between PAHs and exchangeable cations. The result suggests that PAHs photolysis rate depends on cation–π interactions on clay surfaces. Meanwhile, the deposition of anthracene at the Na+-smectite and K+-smectite surface favors solar light absorption, resulting in enhanced direct photodecomposition of PAHs. On the other hand, smectite clays saturated with Fe3+, Al3+, and Cu2+ are highly photoreactive and can act as potential catalysts giving rise to oxidative radicals such as O2−· , which initiate the transformation of PAHs. The present work provides valuable insights into understanding the transformation and fate of PAHs in the natural soil environment and sheds light on the development of technologies for contaminated land remediation

  19. Exchangeable cations-mediated photodegradation of polycyclic aromatic hydrocarbons (PAHs) on smectite surface under visible light

    Energy Technology Data Exchange (ETDEWEB)

    Jia, Hanzhong, E-mail: jiahz@ms.xjb.ac.cn [Laboratory of Environmental Sciences and Technology, Xinjiang Technical Institute of Physics & Chemistry, Key Laboratory of Functional Materials and Devices for Special Environments, Chinese Academy of Sciences, Urumqi 830011 (China); Li, Li [Laboratory of Environmental Sciences and Technology, Xinjiang Technical Institute of Physics & Chemistry, Key Laboratory of Functional Materials and Devices for Special Environments, Chinese Academy of Sciences, Urumqi 830011 (China); Chen, Hongxia; Zhao, Yue [Laboratory of Environmental Sciences and Technology, Xinjiang Technical Institute of Physics & Chemistry, Key Laboratory of Functional Materials and Devices for Special Environments, Chinese Academy of Sciences, Urumqi 830011 (China); School of Geology and Mining Engineering, Xinjiang University, Urumqi 830046 (China); Li, Xiyou [Laboratory of Environmental Sciences and Technology, Xinjiang Technical Institute of Physics & Chemistry, Key Laboratory of Functional Materials and Devices for Special Environments, Chinese Academy of Sciences, Urumqi 830011 (China); Wang, Chuanyi, E-mail: cywang@ms.xjb.ac.cn [Laboratory of Environmental Sciences and Technology, Xinjiang Technical Institute of Physics & Chemistry, Key Laboratory of Functional Materials and Devices for Special Environments, Chinese Academy of Sciences, Urumqi 830011 (China)

    2015-04-28

    Graphical abstract: Roles of exchangeable cations in PAHs photodegradation on clay surafces under visible light. - Highlights: • Photolysis rate are strongly dependent on the type of cations on clay surface. • The strength of “cation–π” interactions governs the photodegradation rate of PAHs. • Several exchangeable cations could cause a shift in the absorption spectrum of PAHs. • Exchangeable cations influence the type and amount of reactive intermediates. - Abstract: Clay minerals saturated with different exchangeable cations are expected to play various roles in photodegradation of polycyclic aromatic hydrocarbons (PAHs) via direct and/or indirect pathways on clay surfaces. In the present study, anthracene and phenanthrene were selected as molecule probes to investigate the roles of exchangeable cations on their photodegradation under visible light irradiation. For five types of cation-modified smectite clays, the photodegradation rate of anthracene and phenanthrene follows the order: Fe{sup 3+} > Al{sup 3+} > Cu{sup 2+} >> Ca{sup 2+} > K{sup +} > Na{sup +}, which is consistent with the binding energy of cation–π interactions between PAHs and exchangeable cations. The result suggests that PAHs photolysis rate depends on cation–π interactions on clay surfaces. Meanwhile, the deposition of anthracene at the Na{sup +}-smectite and K{sup +}-smectite surface favors solar light absorption, resulting in enhanced direct photodecomposition of PAHs. On the other hand, smectite clays saturated with Fe{sup 3+}, Al{sup 3+}, and Cu{sup 2+} are highly photoreactive and can act as potential catalysts giving rise to oxidative radicals such as O{sub 2}{sup −}· , which initiate the transformation of PAHs. The present work provides valuable insights into understanding the transformation and fate of PAHs in the natural soil environment and sheds light on the development of technologies for contaminated land remediation.

  20. High-Intensity Plasma Glass Melter Final Technical Report

    Energy Technology Data Exchange (ETDEWEB)

    Gonterman, J. Ronald; Weinstein, Michael A.

    2006-10-27

    The purpose of this project was to demonstrate the energy efficiency and reduced emissions that can be obtained with a dual torch DC plasma transferred arc-melting system. Plasmelt Glass Technologies, LLC was formed to solicit and execute the project, which utilize a full-scale test melter system. The system is similar to the one that was originally constructed by Johns Manville, but Plasmelt has added significant improvements to the torch design and melter system that has extended the original JM short torch lives. The original JM design has been shown to achieve melt rates 5 to 10 times faster than conventional gas or electric melting, with improved energy efficiency and reduced emissions. This project began on 7/28/2003 and ended 7/27/06. A laboratory scale melter was designed, constructed, and operated to conduct multiple experimental melting trials on various glass compositions. Glass quality was assessed. Although the melter design is generic and equally applicable to all sectors within the glass industry, the development of this melter has focused primarily on fiberglass with additional exploratory melting trials of frits, specialty, and minerals-melting applications. Throughput, energy efficiency, and glass quality have been shown to be heavily dependent on the selected glass composition. During this project, Plasmelt completed the proof-of-concept work in our Boulder, CO Lab to show the technical feasibility of this transferred-arc plasma melter. Late in the project, the work was focused on developing the processes and evaluating the economic viability of plasma melting aimed at the specific glasses of interest to specific client companies. Post project work is on going with client companies to address broader non-glass materials such as refractories and industrial minerals. Exploratory melting trials have been conducted on several glasses of commercial interest including: C-glass, E-glass, S-Glass, AR-Glass, B-glass, Lighting Glass, NE-Glass, and various

  1. Influence of anionic and cationic polyelectrolytes on the conductivity and morphology of poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) films

    International Nuclear Information System (INIS)

    Conductivity of the poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) strongly depends on the film morphology, which can be altered by the presence of polyelectrolytes. Aqueous dispersion of PEDOT:PSS was studied with anionic sodium polyacrylate (PA) and cationic poly(dimethyldiallylammonium chloride) (pDADMAC) polyelectrolytes that are typically used in papermaking as retention aids and dispersing agents in the paper pigment coating formulations. Spin-coated PEDOT:PSS films on a PA coated glass formed non-uniform layers with lowered conductivity compared to the reference PEDOT:PSS films on a clean glass substrate. On contrary, spin-coated PEDOT:PSS on a pDADMAC coated glass formed uniform layers with good conductivity. These results point out the importance of surface chemistry when using renewable and recyclable paper-based substrates with the PEDOT:PSS films. - Highlights: • PEDOT:PSS polymer was studied in the presence of polyelectrolytes. • Uniform layers of PEDOT:PSS and polyelectrolytes were spin-coated on glass. • Cationic polyelectrolyte was found to be more susceptible to humidity. • Cationic polyelectrolyte improves the conductivity of PEDOT:PSS. • PEDOT:PSS forms non-uniform layers on anionic polyelectrolyte coated glass

  2. Influence of anionic and cationic polyelectrolytes on the conductivity and morphology of poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) films

    Energy Technology Data Exchange (ETDEWEB)

    Valtakari, Dimitar, E-mail: dimitar.valtakari@abo.fi [Abo Akademi University, Laboratory of Paper Coating and Converting, Center for Functional Materials at Biological Interfaces (FUNMAT), Porthansgatan 3, FI-20500 Åbo/Turku (Finland); Bollström, Roger [Omya International AG, CH 4665 Oftringen (Switzerland); Toivakka, Martti; Saarinen, Jarkko J. [Abo Akademi University, Laboratory of Paper Coating and Converting, Center for Functional Materials at Biological Interfaces (FUNMAT), Porthansgatan 3, FI-20500 Åbo/Turku (Finland)

    2015-09-01

    Conductivity of the poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) strongly depends on the film morphology, which can be altered by the presence of polyelectrolytes. Aqueous dispersion of PEDOT:PSS was studied with anionic sodium polyacrylate (PA) and cationic poly(dimethyldiallylammonium chloride) (pDADMAC) polyelectrolytes that are typically used in papermaking as retention aids and dispersing agents in the paper pigment coating formulations. Spin-coated PEDOT:PSS films on a PA coated glass formed non-uniform layers with lowered conductivity compared to the reference PEDOT:PSS films on a clean glass substrate. On contrary, spin-coated PEDOT:PSS on a pDADMAC coated glass formed uniform layers with good conductivity. These results point out the importance of surface chemistry when using renewable and recyclable paper-based substrates with the PEDOT:PSS films. - Highlights: • PEDOT:PSS polymer was studied in the presence of polyelectrolytes. • Uniform layers of PEDOT:PSS and polyelectrolytes were spin-coated on glass. • Cationic polyelectrolyte was found to be more susceptible to humidity. • Cationic polyelectrolyte improves the conductivity of PEDOT:PSS. • PEDOT:PSS forms non-uniform layers on anionic polyelectrolyte coated glass.

  3. Glass Stronger than Steel

    Science.gov (United States)

    Yarris, Lynn

    2011-03-28

    A new type of damage-tolerant metallic glass, demonstrating a strength and toughness beyond that of steel or any other known material, has been developed and tested by a collaboration of researchers from Berkeley Lab and Caltech.

  4. THE COLOR GLASS CONDENSATE.

    Energy Technology Data Exchange (ETDEWEB)

    MCLERRAN,L.

    2001-08-26

    The Color Glass Condensate is a state of high density gluonic matter which controls the high energy limit of hadronic interactions. Its properties are important for the initial conditions for matter produced at RHIC.

  5. Mechanically reinforced glass beams

    DEFF Research Database (Denmark)

    Nielsen, Jens Henrik; Olesen, John Forbes

    2007-01-01

    breakage without any warning or ductility, which can be catastrophic if no precautions are taken. One aspect of this issue is treated here by looking at the possibility of mechanically reinforcing glass beams in order to obtain ductile failure for such a structural component. A mechanically reinforced...... laminated float glass beam is constructed and tested in four-point bending. The beam consist of 4 layers of glass laminated together with a slack steel band glued onto the bottom face of the beam. The glass parts of the tested beams are \\SI{1700}{mm} long and \\SI{100}{mm} high, and the total width of one...... beam is \\SI{4\\times10}{mm}. It is reinforced with a \\SI{3}{mm} high steel band covering the full width of the beam. The experimental setup is described and results for this beam are presented. Furthermore, the results for three similar experiments with a \\SI{6}{mm} steel band reinforcement are briefly...

  6. Synthesis of high quality MCM-48 with binary cationic-nonionic surfactants.

    Science.gov (United States)

    Zhao, Wei; Li, Quanzhi; Wang, Lina; Chu, Jinglong; Qu, Jinkui; Li, Shaohua; Qi, Tao

    2010-05-18

    Highly ordered MCM-48 was synthesized in the hydrothermal system of a mixture of cationic cetyltrimethylammonium bromide (CTAB) and nonionic poly(ethylene glycol) monooctylphenyl ether (Tx-100) using water glass as the silicon source. The effect of various factors, such as the amount of surfactant, CTAB/Tx-100, Si source, crystallization temperature, and crystallization time, on the synthesis were discussed in detail. The local effective surfactant packing parameter theory and the charge balance theory were used to explain the reason that various factors can affect the product structure reasonably. Especially, the role of Tx-100 was expounded. The optimum synthesis conditions for MCM-48 were obtained. PMID:20225814

  7. Cationically polymerizable monomers derived from renewable sources

    Energy Technology Data Exchange (ETDEWEB)

    Crivello, J.V.

    1991-10-01

    The objective of this project is to make use of products obtained from renewable plant sources as monomers for the direct production of polymers which can be used for a wide range of plastic applications. In this report is described progress in the synthesis and polymerization of cationically polymerizable monomers and oligomers derived from botanical oils, terpenes, natural rubber, and lignin. Nine different botanical oils were obtained from various sources, characterized and then epoxidized. Their photopolymerization was carried out using cationic photoinitiators and the mechanical properties of the resulting polymers characterized. Preliminary biodegradation studies are being conducted on the photopolymerized films from several of these oils. Limonene was cationically polymerized to give dimers and the dimers epoxidized to yield highly reactive monomers suitable for coatings, inks and adhesives. The direct phase transfer epoxidation of squalene and natural rubber was carried out. The modified rubbers undergo facile photocrosslinking in the presence of onium salts to give crosslinked elastomers. 12 refs., 3 figs., 10 tabs.

  8. Display innovations through glass

    Science.gov (United States)

    Hamilton, Lori L.

    2016-03-01

    Prevailing trends in thin, lightweight, high-resolution, and added functionality, such as touch sensing, continue to drive innovation in the display market. While display volumes grow, so do consumers’ need for portability, enhanced optical performance, and mechanical reliability. Technical advancements in glass design and process have enabled display innovations in these areas while supporting industry growth. Opportunities for further innovation remain open for glass manufacturers to drive new applications, enhanced functionality, and increased demand.

  9. Thermal Conductivity of Foam Glass

    DEFF Research Database (Denmark)

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

    Due to the increased focus on energy savings and waste recycling foam glass materials have gained increased attention. The production process of foam glass is a potential low-cost recycle option for challenging waste, e.g. CRT glass and industrial waste (fly ash and slags). Foam glass is used as...... only closed pores and its overall thermal conductivity will be much lower than that of the foam glass with open pores. In this work we have prepared foam glass using different types of recycled glasses and different kinds of foaming agents. This enabled the formation of foam glasses having gas cells...... glass types could have a significant advantage for getting low thermal conductivity when recycled for thermal insulation applications. The impact of crystallisation on the thermal conductivity of foam glasses is also discussed....

  10. Association of ionic liquids with cationic dyes in aqueous solution: A thermodynamic study

    International Nuclear Information System (INIS)

    Highlights: ► Precipitate was formed between cationic dye and ionic liquid in aqueous solution. ► Precipitates are 1:1 formed by cation of the dyes and anion of the ionic liquids. ► Association constants decrease with increasing temperature. ► The associates can be used as active materials of ion-selective electrode. - Abstract: In this paper, the interactions between cationic dyes and the ionic liquids (ILs) have been studied by 31P nuclear magnetic resonance (NMR), UV–Vis spectroscopy and conductometric measurements at different temperatures. It was shown that a decrease in the measured specific conductance of the (dye + IL) mixtures was caused by the formation of non-conducting or less conducting (dye + IL) associates. The associates were formed by 1:1 ratio of cation of the cationic dyes and anion of the ILs by using the 31P NMR and UV–Vis spectroscopy methods. The association constants were calculated by theoretical model based on the deviation from linear behavior, and the association constants were as high as 106 (L · mol−1)2. Thermodynamic results imply that the formation process of association was exothermic nature. It is expected that the associates reported here would have promising application as active materials for the preparation of ion-selective electrode used in the determination of ILs concentrations.

  11. Phase separation and crystallization of UMo glass

    International Nuclear Information System (INIS)

    Reprocessing of spent UMo metal fuel has produced fission product solutions in nitric acid. The vitrification of these Mo-rich highly active solutions is currently being studied. The high Mo concentration combined with notable amounts of phosphorus has led to the formulation of a glass-ceramic wasteform characterized by Mo-P-Zn enriched nodules uniformly distributed in a glassy phase. The final microstructure resulting from the selected cooling scenario reveals the contributions of phase separation and crystallization phenomena. Isothermal heat treatments and quick quenching were tested on previously quenched glass samples, which were then submitted to SEM and XRD analysis. The following glass transformation mechanism during cooling are proposed: initial metastable phase separation at high temperature, followed by coalescence of the separated droplets and crystallization of the residual liquid in the droplets. (authors)

  12. Preliminary Testing For Anionic, Cationic and Non-ionic

    Directory of Open Access Journals (Sweden)

    Bokic, Lj.

    2007-11-01

    Full Text Available Detergents present a major environmental problem due to large quantities of surfactants released from laundries. For this reason, it is important to apply an appropriate analytical method for their determination. In this work, we propose two simple, fast and inexpensive analytical methods for anionic, cationic and non-ionic surfactant determination: thin layer chromatography (TLC separation for qualitative screening and quantitative potentiometric determination with ion-selective electrodes. These methods have been chosen because of their many advantages: rapidity, ease of operation, low cost of analysis and a wide variety of TLC application possibilities. The advantage of potentiometric titration is its very high degree of automation and very low detection limits obtained with different ion-selective electrodes applied for different surfactants.

  13. Organic non-aqueous cation-based redox flow batteries

    Energy Technology Data Exchange (ETDEWEB)

    Jansen, Andrew N.; Vaughey, John T.; Chen, Zonghai; Zhang, Lu; Brushett, Fikile R.

    2016-03-29

    The present invention provides a non-aqueous redox flow battery comprising a negative electrode immersed in a non-aqueous liquid negative electrolyte, a positive electrode immersed in a non-aqueous liquid positive electrolyte, and a cation-permeable separator (e.g., a porous membrane, film, sheet, or panel) between the negative electrolyte from the positive electrolyte. During charging and discharging, the electrolytes are circulated over their respective electrodes. The electrolytes each comprise an electrolyte salt (e.g., a lithium or sodium salt), a transition-metal free redox reactant, and optionally an electrochemically stable organic solvent. Each redox reactant is selected from an organic compound comprising a conjugated unsaturated moiety, a boron cluster compound, and a combination thereof. The organic redox reactant of the positive electrolyte is selected to have a higher redox potential than the redox reactant of the negative electrolyte.

  14. Ion selectivity of graphene nanopores.

    Science.gov (United States)

    Rollings, Ryan C; Kuan, Aaron T; Golovchenko, Jene A

    2016-01-01

    As population growth continues to outpace development of water infrastructure in many countries, desalination (the removal of salts from seawater) at high energy efficiency will likely become a vital source of fresh water. Due to its atomic thinness combined with its mechanical strength, porous graphene may be particularly well-suited for electrodialysis desalination, in which ions are removed under an electric field via ion-selective pores. Here, we show that single graphene nanopores preferentially permit the passage of K(+) cations over Cl(-) anions with selectivity ratios of over 100 and conduct monovalent cations up to 5 times more rapidly than divalent cations. Surprisingly, the observed K(+)/Cl(-) selectivity persists in pores even as large as about 20 nm in diameter, suggesting that high throughput, highly selective graphene electrodialysis membranes can be fabricated without the need for subnanometer control over pore size. PMID:27102837

  15. Ion selectivity of graphene nanopores

    Science.gov (United States)

    Rollings, Ryan C.; Kuan, Aaron T.; Golovchenko, Jene A.

    2016-01-01

    As population growth continues to outpace development of water infrastructure in many countries, desalination (the removal of salts from seawater) at high energy efficiency will likely become a vital source of fresh water. Due to its atomic thinness combined with its mechanical strength, porous graphene may be particularly well-suited for electrodialysis desalination, in which ions are removed under an electric field via ion-selective pores. Here, we show that single graphene nanopores preferentially permit the passage of K+ cations over Cl− anions with selectivity ratios of over 100 and conduct monovalent cations up to 5 times more rapidly than divalent cations. Surprisingly, the observed K+/Cl− selectivity persists in pores even as large as about 20 nm in diameter, suggesting that high throughput, highly selective graphene electrodialysis membranes can be fabricated without the need for subnanometer control over pore size. PMID:27102837

  16. Ab initio modeling of glass corrosion: Hydroxylation and chemisorption of oxalic acid at diopside and akermanite surfaces

    International Nuclear Information System (INIS)

    Using ab initio density functional theory, we have performed a systematic study of corrosion processes at pure and at hydroxylated surfaces of the silicate minerals diopside (CaMgSi2O6) and akermanite (Ca2MgSi2O7), serving as model systems for multicomponent glasses. The tendency of the cations to assume their ideal bulk coordination was identified as the driving force behind spontaneous surface relaxation and hydroxylation in an aqueous environment. Surface complexes formed after exposing the glass surfaces to oxalic acid form a protective hydrophobic layer on the surface and thus prevent the leaching of metal cations from the glass surface. This provides a description of the mechanism of glass corrosion inhibition at the atomic level: as the chemisorption energy of oxalic acid is larger than the physisorption energy of water, the former is the process that will actually occur.

  17. Cation Effect on Copper Chemical Mechanical Polishing

    Institute of Scientific and Technical Information of China (English)

    WANG Liang-Yong; LIU Bo; SONG Zhi-Tang; FENG Song-Lin

    2009-01-01

    We examine the effect of cations in solutions containing benzotriazole (BTA) and H2O2 on copper chemical mechanical polishing (CMP). On the base of atomic force microscopy (AFM) and material removal rate (MRR) results, it is found that ammonia shows the highest MRR as well as good surface after CMP, while KOH demon-strates the worst performance. These results reveal a mechanism that sma//molecules with lone-pairs rather than molecules with steric effect and common inorganic cations are better for copper CMP process, which is indirectly confirmed by open circuit potential (OCP).

  18. Fundamental studies on ionomer glasses

    OpenAIRE

    Wood, David John

    1993-01-01

    Composition-structure-property relationships were studied in glasses of the type used to produce glass lonomer dental cements. These materials are currently being developed as a bone cement in joint replacement surgery. Initially, a simple quaternary (25i02-Al203-CaO-CaF2) glass was produced and was found to undergo minimal fluorine loss. This results in a glass whose composition is reproducible between batches. This composition, however, was too reactive to form a glass ionomer cem...

  19. Biphasic Catalytic(Hydroformylation of 1-Dodecene in Micellar System with Cationic Gemini Surfactants

    Institute of Scientific and Technical Information of China (English)

    Min LI; Bin XU; Hua CHEN; Hong Jie ZHENG; Xue Yuan HUANG; Yao Zhong LI; Xian Jun LI

    2004-01-01

    The promotion effect of cationic gemini surfactants for the hydroformylation of 1-dodecene in the organic/aqueous biphasic catalytic system is reported. The hydroformylation reaction in the presence of gemini surfactant occurred with higher turnover frequency and higher selectivity for linear aldehyde than using conventional monomeric surfactant CTAB.

  20. Modeling hysteresis observed in the human erythrocyte voltage-dependent cation channel

    DEFF Research Database (Denmark)

    Flyvbjerg, Henrik; Gudowska-Nowak, Ewa; Christophersen, Palle;

    2012-01-01

    The non-selective voltage-activated cation channel from human red cells, which is activated at depolarizing potentials, has been shown to exhibit counter-clockwise gating hysteresis. Here, we analyze this phenomenon with the simplest possible phenomenological models. Specifically, the hysteresis...

  1. Applications of physical chemistry to glass technology

    Science.gov (United States)

    Stewart, Ogie Gregory

    2001-07-01

    Industrial manufacturing of glass, called float glass, involves a process in which flat pieces of glass are produced by pouring molten glass on a bath of molten tin metal. The glass is then coated with thin film coatings for such applications as solar radiation control and "privacy" glass. In this thesis, principles of physical chemistry are applied to selected aspects of glass production and thin film coatings in an effort to better understand these processes with the hope of improving film and glass quality. The research described here consists of three major studies. Part 1 describes the production of thin films by Atmospheric Pressure Chemical Vapor Deposition (APCVD) and characterization of the films by various analytical techniques. Vanadium oxide films were produced from vanadium (IV) chloride and each of several alcohols to determine the feasibility of this method of deposition and to investigate its use in an electrochromic device. The focus here was to investigate the levels of carbon contamination in the films. It was found that the level of carbon present in the films depend on the type of amine used. Part 2 is an investigation of the flow dynamics that occur during the two thin film deposition processes. APCVD and Powder Spray Pyrolysis (PSP). Information regarding flow dynamics and particle distribution in the region above the films' substrates were obtained and related to film formation and quality. Part 3 is a kinetic study of the gas phase reactions that occur in the vapor region above the glass during float glass production. A kinetic model of the possible reactions was devised and integrated to predict the formation of these impurities with time. An experimental setup to test the model's predictions is also discussed. The research described in this thesis lays the groundwork for several possibilities for future work. Electrochromic films can be produced by APCVD to construct an all-solid-state device. Two dimensional imaging coupled with Laser

  2. Wastes based glasses and glass-ceramics

    Directory of Open Access Journals (Sweden)

    Barbieri, L.

    2001-12-01

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

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

  3. Glass-ceramics: A class of nanostructured materials for photonics

    International Nuclear Information System (INIS)

    Glass-ceramics (GCs) are constituted by nanometer–to–micron-sized crystals embedded in a glass matrix; usually, their structural or functional elements (clusters, crystallites or molecules) have dimensions in the 1 to 100 nm range. As the name says, GCs must be considered an intermediate material between inorganic glasses and ceramics; in most cases the crystallinity is between 30 and 50%. GCs share many properties with both glasses and ceramics, offering low defects, extra hardness, high thermal shock resistance (typical of ceramics) together with the ease of fabrication and moulding (typical of glasses). The embedded crystalline phase, however, can enhance the existing properties of the matrix glass or lead to entirely new properties. GCs are produced by controlled crystallization of certain glasses, generally induced by nucleating additives; they may result opaque or transparent. Transparent GCs are now gaining a competitive advantage with respect to amorphous glasses and, sometimes, to crystals too. The aim of the present paper is to introduce the basic characteristics of transparent glass-ceramics, with particular attention to the relationship between structure and transparency and to the mechanism of crystallization, which may also be induced by selective laser treatments. Their applications to the development of guided-wave structures are also briefly described.

  4. Glass-ceramics: A class of nanostructured materials for photonics

    Science.gov (United States)

    de Pablos-Martin, A.; Ferrari, M.; Pascual, M. J.; Righini, G. C.

    2015-07-01

    Glass-ceramics (GCs) are constituted by nanometer-to-micron-sized crystals embedded in a glass matrix; usually, their structural or functional elements (clusters, crystallites or molecules) have dimensions in the 1 to 100nm range. As the name says, GCs must be considered an intermediate material between inorganic glasses and ceramics; in most cases the crystallinity is between 30 and 50%. GCs share many properties with both glasses and ceramics, offering low defects, extra hardness, high thermal shock resistance (typical of ceramics) together with the ease of fabrication and moulding (typical of glasses). The embedded crystalline phase, however, can enhance the existing properties of the matrix glass or lead to entirely new properties. GCs are produced by controlled crystallization of certain glasses, generally induced by nucleating additives; they may result opaque or transparent. Transparent GCs are now gaining a competitive advantage with respect to amorphous glasses and, sometimes, to crystals too. The aim of the present paper is to introduce the basic characteristics of transparent glass-ceramics, with particular attention to the relationship between structure and transparency and to the mechanism of crystallization, which may also be induced by selective laser treatments. Their applications to the development of guided-wave structures are also briefly described.

  5. Binding properties of oxacalix[4]arenes derivatives toward metal cations

    International Nuclear Information System (INIS)

    The objective of this work was to establish the binding properties of oxacalix[4]arene derivatives with different numbers of the oxa bridges, functional groups (ketones, pyridine, ester, amide and methoxy) and conformations. Their interactions with alkali and alkaline-earth, heavy and transition metal cations have been evaluated according to different approaches: (i) extraction of corresponding picrates from an aqueous phase into dichloromethane; (ii) determination of the thermodynamic parameters of complexation in methanol and/or acetonitrile by UV-spectrophotometry and micro-calorimetry; (iii) determination of the stoichiometry of the complexes by ESI-MS; (iv) 1H-NMR titrations allowing to localize the metal ions in the ligand cavity. In a first part dealing on homo-oxacalix[4]arenes, selectivities for Na+, K+, Ca2+, Pb2+ and Mn2+ of ketones derivatives was shown. The presence of oxa bridge in these derivatives increases their efficiency while decreasing their selectivity with respect to related calixarenes. The pyridine derivative prefers transition and heavy metal cations, in agreement with the presence of the soft nitrogen atoms. In the second part, di-oxacalix[4]arene ester and secondary amide derivatives were shown to be less effective than tertiary amide counterparts but to present high selectivities for Li+, Ba2+, Zn2+ and Hg2+. A third part devoted to the octa-homo-tetra-oxacalix[4]arene tetra-methoxy shows that the 1:1 metal complexes formed are generally more stable than those of calixarenes, suggesting the participation of the oxygen atoms of the bridge in the complexation. Selectivity for Cs+, Ba2+, Cu2+ and Hg2+ were noted. (author)

  6. Cationic ruthenium-cyclopentadienyl-diphosphine complexes as catalysts for the allylation of phenols with allyl alcohol: relation between structure and catalytic performance in O- vs. C-allylation

    NARCIS (Netherlands)

    van Rijn, J.A.; Lutz, M.; von Chrzanowski, L.S.; Spek, A.L.; Bouwman, E.; Drent, E.

    2009-01-01

    A new catalytic method has been investigated to obtain either O- or C-allylated phenolic products using allyl alcohol or diallyl ether as the allyl donor. With the use of new cationic ruthenium(II) complexes as catalyst, both reactions can be performed with good selectivity. Active cationic Ru(II) c

  7. Glass microsphere lubrication

    Science.gov (United States)

    Geiger, Michelle; Goode, Henry; Ohanlon, Sean; Pieloch, Stuart; Sorrells, Cindy; Willette, Chris

    1991-01-01

    The harsh lunar environment eliminated the consideration of most lubricants used on earth. Considering that the majority of the surface of the moon consists of sand, the elements that make up this mixture were analyzed. According to previous space missions, a large portion of the moon's surface is made up of fine grained crystalline rock, about 0.02 to 0.05 mm in size. These fine grained particles can be divided into four groups: lunar rock fragments, glasses, agglutinates (rock particles, crystals, or glasses), and fragments of meteorite material (rare). Analysis of the soil obtained from the missions has given chemical compositions of its materials. It is about 53 to 63 percent oxygen, 16 to 22 percent silicon, 10 to 16 percent sulfur, 5 to 9 percent aluminum, and has lesser amounts of magnesium, carbon, and sodium. To be self-supporting, the lubricant must utilize one or more of the above elements. Considering that the element must be easy to extract and readily manipulated, silicon or glass was the most logical choice. Being a ceramic, glass has a high strength and excellent resistance to temperature. The glass would also not contaminate the environment as it comes directly from it. If sand entered a bearing lubricated with grease, the lubricant would eventually fail and the shaft would bind, causing damage to the system. In a bearing lubricated with a solid glass lubricant, sand would be ground up and have little effect on the system. The next issue was what shape to form the glass in. Solid glass spheres was the only logical choice. The strength of the glass and its endurance would be optimal in this form. To behave as an effective lubricant, the diameter of the spheres would have to be very small, on the order of hundreds of microns or less. This would allow smaller clearances between the bearing and the shaft, and less material would be needed. The production of glass microspheres was divided into two parts, production and sorting. Production includes the

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

    DEFF Research Database (Denmark)

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

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

  9. DWPF GLASS BEADS AND GLASS FRIT TRANSPORT DEMONSTRATION

    Energy Technology Data Exchange (ETDEWEB)

    Adamson, D; Bradley Pickenheim, B

    2008-11-24

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

  10. Optical glass: standards - present state and outlook

    Science.gov (United States)

    Hartmann, Peter

    2015-10-01

    In 1996, the international organization for standardization ISO started the standards series ISO 10110 specifying indications in drawings of optical elements. Three parts cover material properties: part 2 (stress birefringence), 3 (bubbles and inclusions), and 4 (inhomogeneity and striae). Customers used to just send optical element drawings to glass manufacturers often leading to uncertainty, overspecification, and delivery problems. The raw glass standard ISO 12123 of 2010 allows direct addressing of raw glass specifications. Harmonizing ISO 10110 with ISO 12123 and progress in inspection methods require updating of the material specifying parts. A new part 18 containing all properties is under preparation and is meant to replace parts 2-4. ISO 12123 will be amended by introducing definitions for relative partial dispersions and reference normal lines and grade denominations for tolerance ranges. The working draft ISO/WD 10110 part 18 extends indication possibilities to allow relating to ISO 12123 while ensuring backward compatibility. Default optical glass quality and direct specification of raw glass simplify tolerancing considerably. Annexes support selection of appropriate quality classes referring to optical element size categories. Test and inspection standards on chemical resistances, hardness, stress birefringence, and optical homogeneity will be maintained. Standards for water resistance, refractive index, and striae inspection are being prepared.

  11. Alkaline glass as induced fission fragment detectors

    International Nuclear Information System (INIS)

    The slide glass, registered trade marks INLAB, INVICT and PERFECTA were compared. For the three kinds of glasses the following studies were done: chemical composition; general dissolution rate for hydrofluoric acid solutions of concentrations between 1 and 10M, at 300C and ultrasound shaking; relative efficiency for recording fission fragment tracks from 252Cf. The INLAB glass was selected due to the better quality of its surface after chemical etching. The HF concentration 2.5M was determined for chemical etching of INLAB glass, and the optimum etching time was chosen between 8 and 10 minutes. The thermal attenuation of latent tracks in the environmental temperature was observed for intervals uo to 31 days between the detector exposure to the fission fragment source and etching of tracks. Several methods were used for determining the detector parameters, such as: critical angle, angle of the cone and efficiency of etching. The effects of gamma irradiation from 60Co and reactor neutrons in material properties as track detector were studied. Attenuation of latent tracks and saturation of color centers were observed for doses over 100M Rad. Since this kind of material contains uranium as impurity, uniformely distributed, slide glass were calibrated to be applied as a monitor of thermal neutron flux in nuclear reactor. (Author)

  12. Ultrafast studies on the photophysics of matrix-isolated radical cations of polycyclic aromatic hydrocarbons: implications for the Diffuse Interstellar Bands (DIB) problem

    CERN Document Server

    Zhao, L; Shkrob, I A; Crowell, R A; Pommeret, S; Chronister, E L; Liu, A D; Trifunac, A D; Zhao, Liang; Lian, Rui; Shkrob, Ilya A.; Crowell, Robert A.; Pommeret, Stanislas; Chronister, Eric L.; Liu, An Dong; Trifunac, Alexander D.

    2004-01-01

    Rapid, efficient deactivation of the photoexcited PAH cations accounts for their remarkable photostability and have important implications for astrochemistry, as these cations are the leading candidates for the species responsible for the diffuse interstellar bands (DIB) observed throughout the Galaxy.Ultrafast relaxation dynamics for photoexcited PAH cations isolated in boric acid glass have been studied using femtosecond and picosecond transient grating spectroscopy. With the exception of perylene+, the recovery kinetics for the ground doublet (D0) states of these radical cations are biexponential, containing a fast (< 200 fs) and a slow (3-20 ps) components. No temperature dependence or isotope effect was observed for the fast component, whereas the slow component exhibits both the H/D isotope effect (1.1-1.3) and strong temperature dependence (15 to 300 K). We suggest that the fast component is due to internal Dn to D0 conversion and the slow component is due to vibrational energy transfer (VET) from a...

  13. Eletrodo íon-seletivo para determinação potenciométrica de alumínio(III) em meio de fluoreto Ion-selective electrode for potentiometric determination of aluminium(III) in fluoride medium

    OpenAIRE

    Evandro Piccin; Orlando Fatibello-Filho; Luiz Antonio Ramos

    2004-01-01

    The construction and analytical evaluation of a coated graphite Al(III) ion-selective electrode, based on the ionic pair formed between the Al(F)n3-n anion and tricaprylylmethylammonium cation (Aliquat 336S) incorporated on a poly(vinylchloride) (PVC) matrix membrane are described. A thin membrane film of this ionic pair and dibutylphthalate (DBPh) in PVC was deposited directly on a cylindric graphite rod (2 cm length x 0.5 cm diameter) attached to the end of a glass tube using epoxy resin. T...

  14. The Study of Optical Properties as Glass Composition of Bi2O3-Based Glass/Phosphor Mixed Paste.

    Science.gov (United States)

    Hwang, M K; Kim, I G; Jung, Y K; Ryu, B K

    2015-10-01

    Recently, White light emitting diodes (WLEDs) have been studied because of many advantages such as lower energy consumption, fast response, high brightness. Glass frit has been interested in LED packages due to their superior properties such as long-term stability and permeability. To maximize the LED light emission characteristic, the glass frit was required a low firing temperature and high refractive index. We selected the bismuth-based glass due to their low melting and high refractive index. This study was investigated characteristics of glass according to the influence of the glass within Bi2O3 content and this glass characteristic change was studied the effects on the optical properties of LED package structure. The properties changes of the glass frit affect the optical property of the mixed paste. With higher contents of Bi203 glass composition, the transmittance and emission intensity of the mixed paste was increased. These results suggest that the difference in refractive index between the phosphor and glass frit is minimized, the loss of light is minimized. PMID:26726391

  15. Method for encapsulating and isolating hazardous cations, medium for encapsulating and isolating hazardous cations

    Energy Technology Data Exchange (ETDEWEB)

    Wasserman, S.R.; Anderson, K.B.; Song, K.; Yuchs, S.E.; Marshall, C.L.

    1996-12-31

    The problems associated with the disposal of toxic metals in an environmentally acceptable manner continues to plague industry. Such metals as nickel, vanadium, molybdenum, cobalt, iron, and antimony present physiological and ecological challenges that are best addressed through minimization of exposure and dispersion. A method for encapsulating hazardous cations is provided comprising supplying a pretreated substrate containing the cations; contacting the substrate with an organo-silane compound to form a coating on the substrate; and allowing the coating to cure. A medium for containing hazardous cations is also provided, comprising a substrate having ion-exchange capacity and a silane-containing coating on the substrate.

  16. Binding properties of oxacalix[4]arenes derivatives toward metal cations; Interactions entre cations metalliques et derives des oxacalix[4]arenes

    Energy Technology Data Exchange (ETDEWEB)

    Mellah, B

    2006-11-15

    The objective of this work was to establish the binding properties of oxacalix[4]arene derivatives with different numbers of the oxa bridges, functional groups (ketones, pyridine, ester, amide and methoxy) and conformations. Their interactions with alkali and alkaline-earth, heavy and transition metal cations have been evaluated according to different approaches: (i) extraction of corresponding picrates from an aqueous phase into dichloromethane; (ii) determination of the thermodynamic parameters of complexation in methanol and/or acetonitrile by UV-spectrophotometry and micro-calorimetry; (iii) determination of the stoichiometry of the complexes by ESI-MS; (iv) {sup 1}H-NMR titrations allowing to localize the metal ions in the ligand cavity. In a first part dealing on homo-oxacalix[4]arenes, selectivities for Na{sup +}, K{sup +}, Ca{sup 2+}, Pb{sup 2+} and Mn{sup 2+} of ketones derivatives was shown. The presence of oxa bridge in these derivatives increases their efficiency while decreasing their selectivity with respect to related calixarenes. The pyridine derivative prefers transition and heavy metal cations, in agreement with the presence of the soft nitrogen atoms. In the second part, di-oxacalix[4]arene ester and secondary amide derivatives were shown to be less effective than tertiary amide counterparts but to present high selectivities for Li{sup +}, Ba{sup 2+}, Zn{sup 2+} and Hg{sup 2+}. A third part devoted to the octa-homo-tetra-oxacalix[4]arene tetra-methoxy shows that the 1:1 metal complexes formed are generally more stable than those of calixarenes, suggesting the participation of the oxygen atoms of the bridge in the complexation. Selectivity for Cs{sup +}, Ba{sup 2+}, Cu{sup 2+} and Hg{sup 2+} were noted. (author)

  17. Sorption of alkylammonium cations on montmorillonite

    Czech Academy of Sciences Publication Activity Database

    Navrátilová, Z.; Wojtowicz, P.; Vaculíková, Lenka; Šugárková, Věra

    2007-01-01

    Roč. 4, 3/147/ (2007), s. 59-65. ISSN 1214-9705 R&D Projects: GA ČR GA205/05/0871 Institutional research plan: CEZ:AV0Z30860518 Keywords : montmorillonite * adsorption * alkylammonium cations Subject RIV: CB - Analytical Chemistry, Separation

  18. Cationic flotation of some lithium ores

    International Nuclear Information System (INIS)

    The cationic flotation of some lithium ores (spodumene, amblygonite, petalite, lepidolite) is studied by the measure of zeta potential and micro-flotation tests in Hallimond tube. The effect of some modifier agents (corn starch, meta sodium silicate) on the lithium flotation is studied. (M.A.C.)

  19. Simultaneous anion and cation mobility in polypyrrole

    DEFF Research Database (Denmark)

    Skaarup, Steen; Bay, Lasse; Vidanapathirana, K.;

    2003-01-01

    Polypyrrole (PPy) polymer films permanently doped with large, immobile anion dodecyl benzene sulfonate (DBS) have been characterized by cyclic voltammetry in order to clarify the roles of cations and anions in the aqueous electrolyte as mobile ions in the film. Aqueous solutions of 0.05-0.1 M alk...

  20. The bearable lightness of all glass structures

    OpenAIRE

    Nijsse, R

    2015-01-01

    This paper is new developments in structural engineering related especially to the use of the material glass. After a philosophical discussion about why glass is the material for the Future, all glass elements and related techniques are presented from which an all glass building can be assembled. To conclude this paper ,all glass structures like a glass bridge, glass columns, a glass brick wall and a corrugated glass faced are shown in realised projects.

  1. The Future of all glass structures

    OpenAIRE

    Nijsse, R

    2015-01-01

    This paper is new developments in structural engineering related especially to the use of the material glass. After a philosophical discussion about why glass is the material for the Future, all glass elements and related techniques are presented from which an all glass building can be assembled. To conclude this paper ,all glass structures like a glass bridge, glass columns, a glass brick wall and a corrugated glass faced are shown in realised projects.

  2. Diferrocenyl oligothiophene wires: Raman and quantum chemical study of valence-trapped cations

    Energy Technology Data Exchange (ETDEWEB)

    Rodriguez Gonzalez, Sandra; Lopez Navarrete, Juan T.; Casado, Juan [Department of Physical Chemistry, University of Malaga, Campus de Teatinos s/n, 29071 Malaga (Spain); Arago, Juan; Viruela, Pedro M.; Orti, Enrique [Instituto de Ciencia Molecular, Universidad de Valencia, 46980 Paterna, Valencia (Spain); Sato, Masa-aki [Graduate School of Maritime Science, Kobe University, 5-1-1 Fukae-Minami, Higashinada, Kobe 658-0022 (Japan)

    2011-12-21

    A combination of Raman spectroscopy and density functional theory calculations is used to describe the structural and spectroscopic properties of the different isomeric cations of diferrocenyl quaterthiophenes. Isomerisation of the thienyl {beta}-positions provides site selective oxidation, which gives rise to species that can interconvert by moving the charge over the bridge. The spectroscopic study allows us to describe a sequence of stationary trapped cationic, either ferrocenyl or thienyl, states which constitutes an energy cascade of accessible sites through which the charge transfer can proceed.

  3. Thermochemical study of rare earth and nitrogen incorporation in glasses

    Science.gov (United States)

    Zhang, Yahong

    Rare earth containing aluminosilicate, borosilicate, aluminate and nitrogen containing aluminosilicate glasses are technically important materials. They have extraordinary physical and chemical properties such as high glass transition temperature, very low electrical conductivity, and excellent chemical stability. These unique properties lead to applications as coatings on metals and ceramics, optical fibers, semiconductors, and nuclear waste containment materials. In addition, such systems contain the most widely used additives for sintering of Si3N4, SiAlON and SiC ceramics for high temperature applications. Thermodynamic properties and the relations among energetics, structure and bonding are essential to controlling processing parameters to synthesize, at lower cost, materials having better properties. Earlier investigations mainly pertained to specific physical properties of rare-earth doped oxide and oxynitride glasses. Work on the thermodynamic stability and materials compatibility has been very sparse. High temperature solution calorimetry in molten oxide solvents is a powerful tool for the thermodynamic study of refractory materials. With implementation and improvement, this technique has been applied to the first measurement of enthalpies of formation of RE-Si-Al-O glasses, REAlO3 glasses, RE-Si-Al-O-N glasses, and Si3N 4 and Ge3N4 with high pressure spinel structure. The first successful synthesis of REAlO3 glasses has been achieved by containerless melting. Their large enthalpies of crystallization confirm that they are reluctant glass formers. For glasses along the 2REAlO3 -3SiO2 join, the strongly negative heats of mixing support the absence of miscibility gaps except possibly at very high silica content. Energetic evidence has been presented for incipient phase-ordered regions in Gd- or Hf-containing sodium alumino-borosilicate glasses for plutonium immobilization. Linear relations between enthalpies of formation of RESiAlON glasses from elements and

  4. Plutonium immobilization in glass and ceramics

    Energy Technology Data Exchange (ETDEWEB)

    Knecht, D.A. [Lockheed Martin Idaho Technologies, Idaho Falls (United States); Murphy, W.M. [Southwest Research Institute, San Antonio, TX (United States)

    1996-05-01

    The Materials Research Society Nineteenth Annual Symposium on the Scientific Basis for Nuclear Waste Management was held in Boston on November 27 to December 1, 1995. Over 150 papers were presented at the Symposium dealing with all aspects of nuclear waste management and disposal. Fourteen oral sessions and on poster session included a Plenary session on surplus plutonium dispositioning and waste forms. The proceedings, to be published in April, 1996, will provide a highly respected, referred compilation of the state of scientific development in the field of nuclear waste management. This paper provides a brief overview of the selected Symposium papers that are applicable to plutonium immobilization and plutonium waste form performance. Waste forms that were described at the Symposium cover most of the candidate Pu immobilization options under consideration, including borosilicate glass with a melting temperature of 1150 {degrees}C, a higher temperature (1450 {degrees}C) lanthanide glass, single phase ceramics, multi-phase ceramics, and multi-phase crystal-glass composites (glass-ceramics or slags). These Symposium papers selected for this overview provide the current status of the technology in these areas and give references to the relevant literature.

  5. Cationic amphipathic peptides accumulate sialylated proteins and lipids in the plasma membrane of eukaryotic host cells

    OpenAIRE

    Weghuber, Julian; Aichinger, Michael C.; Brameshuber, Mario; Wieser, Stefan; Ruprecht, Verena; Plochberger, Birgit; Madl, Josef; Horner, Andreas; Reipert, Siegfried; Lohner, Karl; Henics, Tamas; Schuetz, Gerhard J

    2011-01-01

    Cationic antimicrobial peptides (CAMPs) selectively target bacterial membranes by electrostatic interactions with negatively charged lipids. It turned out that for inhibition of microbial growth a high CAMP membrane concentration is required, which can be realized by the incorporation of hydrophobic groups within the peptide. Increasing hydrophobicity, however, reduces the CAMP selectivity for bacterial over eukaryotic host membranes, thereby causing the risk of detrimental side-effects. In t...

  6. Atomic layer deposition of alternative glass microchannel plates

    International Nuclear Information System (INIS)

    The technique of atomic layer deposition (ALD) has enabled the development of alternative glass microchannel plates (MCPs) with independently tunable resistive and emissive layers, resulting in excellent thickness uniformity across the large area (20 × 20 cm), high aspect ratio (60:1 L/d) glass substrates. Furthermore, the use of ALD to deposit functional layers allows the optimal substrate material to be selected, such as borosilicate glass, which has many benefits compared to the lead-oxide glass used in conventional MCPs, including increased stability and lifetime, low background noise, mechanical robustness, and larger area (at present up to 400 cm2). Resistively stable, high gain MCPs are demonstrated due to the deposition of uniform ALD resistive and emissive layers on alternative glass microcapillary substrates. The MCP performance characteristics reported include increased stability and lifetime, low background noise (0.04 events cm−2 s−1), and low gain variation (±5%)

  7. Study on the adsorption of 233Pa in glass

    International Nuclear Information System (INIS)

    It is intended to examine the adsorption of protactinium on glass in relation to pH, presence of complexing agents concentration and type of electrolytes. The study was made by using carrier-free 233Pa solution and Pyrex glass tube was selected as adsorbent glass material surface. The adsorption curve of protactinium on glass surface as a function of the pH of the tracer solution showed the existence of two pronounced adsorption regions. It was found that this adsorption can be reduced by using electrolytes or complexing agents. Desorption of protactinium previously adsorbed on the Pyrex glass tube was also studied. Hidrochloric, oxalic and hydrofluoric acid solutions were used for the desorption experiments. (Author)

  8. IMPACTS OF SMALL COLUMN ION EXCHANGE STREAMS ON DWPF GLASS FORMULATION KT07-SERIES GLASS COMPOSITIONS

    Energy Technology Data Exchange (ETDEWEB)

    Fox, K.; Edwards, T.

    2011-01-12

    This report is the third in a series of studies of the impacts of the addition of Crystalline Silicotitanate (CST) and Monosodium Titanate (MST) from the Small Column Ion Exchange (SCIX) process on the Defense Waste Processing Facility (DWPF) glass waste form and the applicability of the DWPF process control models. MST from the Salt Waste Processing Facility is also considered in the study. The KT07-series glasses were selected to evaluate any potential impacts of noble metals on their properties and performance. The glasses characterized thus far for the SCIX study have not included noble metals since they are not typically tracked in sludge batch composition projections. However, noble metals can act as nucleation sites in glass melts, leading to enhanced crystallization. This crystallization can potentially influence the properties and performance of the glass, such as chemical durability, viscosity, and liquidus temperature. The noble metals Ag, Pd, Rh, and Ru were added to the KT07-series glasses in concentrations based on recent measurements of Sludge Batch 6, which was considered to contain a high concentration of noble metals. The KT04-series glasses were used as the baseline compositions. After fabrication, the glasses were characterized to determine their homogeneity, chemical composition, durability, and viscosity. Liquidus temperature measurements are also underway but were not complete at the time of this report. The liquidus temperature results for the KT07-series glasses, along with several of the earlier glasses in the SCIX study, will be documented separately. All of the KT07-series glasses, both quenched and slowly cooled, were found to be amorphous by X-ray diffraction. Chemical composition measurements showed that all of the glasses met their targeted compositions. The Product Consistency Test (PCT) results showed that all of the glasses had chemical durabilities that were far better than that of the Environmental Assessment benchmark glass

  9. Comparison of glass surfaces as a countertop material to existing surfaces

    Energy Technology Data Exchange (ETDEWEB)

    Turo, Laura A.; Winschell, Abigail E.

    2011-09-01

    Gleen Glass, a small production glass company that creates countertops, was selected for the Technology Assistance Program through Pacific Northwest National Laboratory. Gleen Glass was seeking material property analysis comparing glass as a countertop material to current surfaces (i.e. marble, granite and engineered stone). With samples provided from Gleen Glass, testing was done on granite, marble, and 3 different glass surfaces ('Journey,' 'Pebble,' and 'Gleen'). Results showed the glass surfaces have a lower density, lower water absorption, and are stronger in compressive and flexural tests as compared to granite and marble. Thermal shock tests showed the glass failed when objects with a high thermal mass are placed directly on them, whereas marble and granite did not fracture under these conditions.

  10. Bio-Glasses An Introduction

    CERN Document Server

    Jones, Julian

    2012-01-01

    This new work is dedicated to glasses and their variants which can be used as biomaterials to repair diseased and damaged tissues. Bio-glasses are superior to other biomaterials in many applications, such as healing bone by signaling stem cells to become bone cells.   Key features:  First book on biomaterials to focus on bio-glassesEdited by a leading authority on bio-glasses trained by one of its inventors, Dr Larry HenchSupported by the International Commission on Glass (ICG)Authored by members of the ICG Biomedical Glass Committee, with the goal of creating a seamless textb

  11. Glass Stability and Kinetic Analysis of Iron-Metalloid Bulk Metallic Glass

    Science.gov (United States)

    Santhaweesuk, Charuayporn

    Multicomponent Fe-based bulk metallic glasses (BMGs) with a combination of excellent properties such as good soft magnetic properties, high strength, high hardness, and high corrosion resistance have attracted increasing attention both from a basic science research standpoint and due to their industrial application potential. However, many of the elemental additions which lead to the easiest glass formation are expensive. The identification of alloys composed of abundant and inexpensive elements that still retain excellent properties would promote applications for engineering and industry. In short, the development of the Fe-based BMG without any glass-forming metal elements and with high glass forming ability is desired. This study shows that the thermal stability of the Fe-based alloys can be improved beyond a simple rule of mixtures prediction by utilizing a well-balance multi-metalloid approach. The kinetics aspect of glass-forming ability is studied experimentally for Fe-B-Si-P alloys. The systematic variation in alloy composition gives access to differences in phase selection and the final dimensions of glass formation. Two alloys, representing the best glass-forming composition and the poorest glass-forming composition, were studied in terms of their stability to crystallization, solidification microstructure evolution and thermal history. The utility of the wedge-casting technique is developed to examine bulk glass-forming alloys by combining multiple temperature profiles of the quenching melt with a measurement-based kinetic analysis of the phase selection competition and critical cooling rate conditions. Based upon direct thermal measurement, microstructural analysis and kinetic modeling, it was found that both representative alloys show a board spectrum of solidification microstructures which include a critical cooling rate range. The kinetic competition in the formation of certain phases can enhance or detract from the final dimension of bulk glass

  12. Low-frequency Raman scattering in alkali tellurite glasses

    Indian Academy of Sciences (India)

    Angelos G Kalampounias

    2008-10-01

    Raman scattering has been employed to study the alkali-cation size dependence and the polarization characteristics of the low-frequency modes for the glass-forming tellurite mixtures, 0.1M2O–0.9TeO2 (M = Na, K, Rb and Cs). The analysis has shown that the Raman coupling coefficient alters by varying the type of the alkali cation. The addition of alkali modifier in the tellurite network leads to the conversion of the TeO4 units to TeO3 units with a varying number of non-bridging oxygen atoms. Emphasis has also been given to the lowfrequency modes and particular points related to the low-frequency Raman phenomenology are discussed in view of the experimental findings.

  13. New fluoroindate glass compositions

    OpenAIRE

    Messaddeq, Younes; Delben, A. A. S. T.; Aegerter, Michel A.; Soufiane, A.; M. Poulain

    1993-01-01

    The limits of glass formation of new fluoroindate glass compositions have been determined for the basic systems InF3-BaF2-GdF3-20ZnF2-20SrF2-2XFn where X = Na, La and InF3-BaF2-2OZnF2-20SrF2-2GdF3-XFn where X = Ca and Y. The incorporation of small amounts of GaF3 and/or GdF3 increases strongly the thermal glass stability. All the fluoroindate compositions studied are highly transparent in the mid-infrared range; their transmission edge is shifted beyond 7 mum and the theoretical attenuation c...

  14. Perspectives on spin glasses

    CERN Document Server

    Contucci, Pierluigi

    2013-01-01

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

  15. Cation-cation interactions, magnetic communication and reactivity of the pentavalent uraniumion [U(NR)2]+

    Energy Technology Data Exchange (ETDEWEB)

    Spencer, Liam P [Los Alamos National Laboratory; Schelter, Eric J [Los Alamos National Laboratory; Boncella, James M [Los Alamos National Laboratory; Yang, Ping [Los Alamos National Laboratory; Gsula, Robyn L [NON LANL; Scott, Brian L [Los Alamos National Laboratory; Thompson, Joe D [Los Alamos National Laboratory; Kiplinger, Jacqueline L [Los Alamos National Laboratory; Batista, Enrique R [Los Alamos National Laboratory

    2009-01-01

    The dimeric bis(imido) uranium complex [{l_brace}U(NtBu)2(I)(tBu2bpy){r_brace}2] (see picture; U green, N blue, I red) has cation-cation interactions between [U(NR)2]+ ions. This f1-f1 system also displays f orbital communication between uranium(V) centers at low temperatures, and can be oxidized to generate uranium(VI) bis(imido) complexes.

  16. Basaltic glass: alteration mechanisms and analogy with nuclear waste glasses

    International Nuclear Information System (INIS)

    A synthetic basaltic glass was dissolved experimentally at 90 deg. C under static conditions in initially pure water. The basaltic glass dissolution rates measured near and far from equilibrium were compared with those of SON 68 nuclear waste glass. Experimental and literature data notably suggested that the alteration mechanisms for the two glasses are initially similar. Under steady-state concentration conditions, the alteration rate decreased of four orders of magnitude below the initial rate (r0). The same alteration rate decrease was observed for basaltic and nuclear glass. These findings tend to corroborate the analogy of the two glasses alteration kinetics. The effect of dissolved silica in solution, observed through dynamic leach tests with silicon-rich solutions, cannot account for the significant drop in the basaltic glass kinetics. Hence, a protective effect of the glass alteration film was assumed and experimentally investigated. Moreover, modeling with LIXIVER argue for a significant effect of diffusion in the alteration gel

  17. Final Report - Glass Formulation Development and DM10 Melter Testing with ORP LAW Glasses, VSL-09R1510-2, Rev. 0, dated 6/12/09

    Energy Technology Data Exchange (ETDEWEB)

    Kruger, Albert A.; Pegg, I. L.; Matlack, K. S.; Joseph, I.; Muller, I. S.; Gong, W.

    2013-11-13

    The principal objective of the work described in this Final Report is to extend the glass formulation methodology developed in the earlier work by development of acceptable glass compositions for four LAW compositions specified by ORP that cover the range of sulfate to sodium and potassium to sodium ratios expected in Hanford LAW. The glass formulations were designed to exclude titanium and iron as glass former additives, while tin and vanadium as glass former additives were evaluated for beneficial effects in increasing waste loading in the glasses. This was accomplished through a combination of crucible-scale tests and tests on the DM10 melter system. This melter is the most efficient melter platform for screening glass compositions over a wide range of sulfate concentrations and therefore was selected for the present tests. The current tests provide information on melter processing characteristics and off-gas data, including sulfur incorporation and partitioning.

  18. Desorption behavior of cesium from cesium bearing smectite by major cations

    International Nuclear Information System (INIS)

    The desorption behaviors of Cs from Cs bearing smectite by major cations (Na+, K+, Mg2+, Ca2+ and NH4+) were systematically examined. The suspension of the Cs bearing smectite was prepared by reaction of 1 g/L smectite with 75 nM Cs+ solution in 0.02 M NaCl solutions. The desorption behaviors of Cs were examined by adding the major cations of which concentrations ranged from 10-3 to 10-1 N to the smectite suspensions. All cations except for K+ lead to the desorption of Cs from smectite when the concentrations of the added cations increased. On the other hand, K+ plays a role for inhibition of Cs desorption from smectite. The order of the ability for the desorption of Cs from smectite by the major cations was summarized as follow: Ca2+ nearly equals Mg2+ > NH4+ > Na+ > K+. The selectivity coefficients based on Gaines-Thomas convention were estimated from the observed desorption behaviors. (author)

  19. Immobilization of hazardous and radioactive waste into glass structures

    International Nuclear Information System (INIS)

    As a result of more than three decades of international research, glass has emerged as the material of choice for immobilization of a wide range of potentially hazardous radioactive and non-radioactive materials. The ability of glass structures to incorporate and then immobilize many different elements into durable, high integrity, waste glass products is a direct function of the unique random network structure of the glassy state. Every major country involved with long-term management of high-level radioactive waste (HLW) has either selected or is considering glass as the matrix of choice for immobilizing and ultimately, disposing of the potentially hazardous, high-level radioactive material. There are many reasons why glass is preferred. Among the most important considerations are the ability of glass structures to accommodate and immobilize the many different types of radionuclides present in HLW, and to produce a product that not only has excellent technical properties, but also possesses good processing features. Good processability allows the glass to be fabricated with relative ease even under difficult remote-handling conditions necessary for vitrification of highly radioactive material. The single most important property of the waste glass produced is its ability to retain hazardous species within the glass structure and this is reflected by its excellent chemical durability and corrosion resistance to a wide range of environmental conditions. In addition to immobilization of HLW glass matrices are also being considered for isolation of many other types of hazardous materials, both radioactive as well as nonradioactive. This includes vitrification of various actinides resulting from clean-up operations and the legacy of the cold war, as well as possible immobilization of weapons grade plutonium resulting from disarmament activities. Other types of wastes being considered for immobilization into glasses include transuranic wastes, mixed wastes, contaminated

  20. Separation of Th and U using borosilicate glasses

    International Nuclear Information System (INIS)

    Boroaluminosilicate glasses having B2O3 to Na2O ratio 0.23 and 9.8 were prepared by conventional melt-quench method and used as room temperature ion exchanger for the sorption of thorium from aqueous solutions. Various experimental conditions were optimized to achieve selective and maximum uptake of thorium. The studies were extended to synthetic mixtures of thorium and uranium, wherein thorium could be selectively removed in presence of 10 fold excess of uranium. Structural elucidation studies were carried out to understand the ion exchange property of glasses. It is seen that presence of linkages like Si-O- and B-O- in the glasses was responsible for the uptake of metal ions. It is seen that the uptake depends on pH of the solution, composition of glass and the initial concentration of thorium ion in solution. (author)

  1. Modulation of pyridinium cationic lipid-DNA complex properties by pyridinium gemini surfactants and its impact on lipoplex transfection properties.

    Science.gov (United States)

    Sharma, Vishnu Dutt; Lees, Julia; Hoffman, Nicholas E; Brailoiu, Eugen; Madesh, Muniswamy; Wunder, Stephanie L; Ilies, Marc A

    2014-02-01

    The study presents the effects of blending a cationic gemini surfactant into cationic lipid bilayers and its impact on the plasmid DNA compaction and delivery process. Using nanoDSC, dynamic light scattering, zeta potential, and electrophoretic mobility measurements, together with transfection (2D- and 3D-) and viability assays, we identified the main physicochemical parameters of the lipid bilayers, liposomes, and lipoplexes that are affected by the gemini surfactant addition. We also correlated the cationic bilayer composition with the dynamics of the DNA compaction process and with transfection efficiency, cytotoxicity, and the internalization mechanism of the resultant nucleic acid complexes. We found that the blending of gemini surfactant into the cationic bilayers fluidized the supramolecular assemblies, reduced the amount of positive charge required to fully compact the plasmid DNA and, in certain cases, changed the internalization mechanism of the lipoplexes. The transfection efficiency of select ternary lipoplexes derived from cationic gemini surfactants and lipids was several times superior to the transfection efficiency of corresponding binary lipoplexes, also surpassing standard transfection systems. The overall impact of gemini surfactants into the formation and dynamic of cationic bilayers was found to depend heavily on the presence of colipids, their nature, and amount present in lipoplexes. The study confirmed the possibility of combining the specific properties of pyridinium gemini surfactants and cationic lipids synergistically to obtain efficient synthetic transfection systems with negligible cytotoxicity useful for therapeutic gene delivery. PMID:24377350

  2. Glass/Ceramic Composites for Sealing Solid Oxide Fuel Cells

    Science.gov (United States)

    Bansal, Narottam P.; Choi, Sung R.

    2007-01-01

    A family of glass/ceramic composite materials has been investigated for use as sealants in planar solid oxide fuel cells. These materials are modified versions of a barium calcium aluminosilicate glass developed previously for the same purpose. The composition of the glass in mole percentages is 35BaO + 15CaO + 5Al2O3 + 10B2O3 + 35SiO2. The glass seal was found to be susceptible to cracking during thermal cycling of the fuel cells. The goal in formulating the glass/ ceramic composite materials was to (1) retain the physical and chemical advantages that led to the prior selection of the barium calcium aluminosilicate glass as the sealant while (2) increasing strength and fracture toughness so as to reduce the tendency toward cracking. Each of the composite formulations consists of the glass plus either of two ceramic reinforcements in a proportion between 0 and 30 mole percent. One of the ceramic reinforcements consists of alumina platelets; the other one consists of particles of yttria-stabilized zirconia wherein the yttria content is 3 mole percent (3YSZ). In preparation for experiments, panels of the glass/ceramic composites were hot-pressed and machined into test bars.

  3. Assessment, development, and testing of glass for blast environments.

    Energy Technology Data Exchange (ETDEWEB)

    Glass, Sarah Jill

    2003-06-01

    Glass can have lethal effects including fatalities and injuries when it breaks and then flies through the air under blast loading (''the glass problem''). One goal of this program was to assess the glass problem and solutions being pursued to mitigate it. One solution to the problem is the development of new glass technology that allows the strength and fragmentation to be controlled or selected depending on the blast performance specifications. For example the glass could be weak and fail, or it could be strong and survive, but it must perform reliably. Also, once it fails it should produce fragments of a controlled size. Under certain circumstances it may be beneficial to have very small fragments, in others it may be beneficial to have large fragments that stay together. The second goal of this program was to evaluate the performance (strength, reliability, and fragmentation) of Engineered Stress Profile (ESP) glass under different loading conditions. These included pseudo-static strength and pressure tests and free-field blast tests. The ultimate goal was to provide engineers and architects with a glass whose behavior under blast loading is less lethal. A near-term benefit is a new approach for improving the reliability of glass and modifying its fracture behavior.

  4. A XANES study of chromophores in archaeological glass

    Energy Technology Data Exchange (ETDEWEB)

    Arletti, Rossella [Universita di Torino, Dipartimento di Scienze della Terra, Torino (Italy); Quartieri, Simona [Universita di Messina, Dipartimento di Fisica e Scienze della Terra, Messina S' Agata (Italy); Freestone, Ian C. [Institute of Archaeology, London (United Kingdom)

    2013-04-15

    We applied X-ray absorption near edge spectroscopy (XANES) to obtain information on the origin of glass colour of several archaeological samples and on the oxidation conditions employed during their production. We studied a series of selected glass fragments - mainly from excavated primary and secondary production centres and dated to the first millennium AD - containing iron and manganese in a wide compositional range. In most of the studied samples iron is rather oxidised, while Mn K-edge XANES data show that, in all the studied glasses, Mn is mainly present in its reduced form (predominantly 2+), with the possible subordinate presence of Mn{sup 3+}. The most oxidised samples are the HIMT (high iron manganese titanium) glasses, while the less oxidised ones belong to the primary natron glass series from the early Islamic tank furnaces at Bet Eliezer (Israel), and to the series coming from a Roman glass workshop excavated in Basinghall Street, London. In these glasses, iron is approximately equally distributed over the 2+ and 3+ oxidation states. The XANES analyses of two glasses which had been deliberately decolourized using Sb- and Mn-based decolourizers demonstrate that Sb is more effective than Mn as oxidant. (orig.)

  5. A XANES study of chromophores in archaeological glass

    International Nuclear Information System (INIS)

    We applied X-ray absorption near edge spectroscopy (XANES) to obtain information on the origin of glass colour of several archaeological samples and on the oxidation conditions employed during their production. We studied a series of selected glass fragments - mainly from excavated primary and secondary production centres and dated to the first millennium AD - containing iron and manganese in a wide compositional range. In most of the studied samples iron is rather oxidised, while Mn K-edge XANES data show that, in all the studied glasses, Mn is mainly present in its reduced form (predominantly 2+), with the possible subordinate presence of Mn3+. The most oxidised samples are the HIMT (high iron manganese titanium) glasses, while the less oxidised ones belong to the primary natron glass series from the early Islamic tank furnaces at Bet Eliezer (Israel), and to the series coming from a Roman glass workshop excavated in Basinghall Street, London. In these glasses, iron is approximately equally distributed over the 2+ and 3+ oxidation states. The XANES analyses of two glasses which had been deliberately decolourized using Sb- and Mn-based decolourizers demonstrate that Sb is more effective than Mn as oxidant. (orig.)

  6. Integrated Disposal Facility FY 2012 Glass Testing Summary Report

    Energy Technology Data Exchange (ETDEWEB)

    Pierce, Eric M.; Kerisit, Sebastien N.; Krogstad, Eirik J.; Burton, Sarah D.; Bjornstad, Bruce N.; Freedman, Vicky L.; Cantrell, Kirk J.; Snyder, Michelle MV; Crum, Jarrod V.; Westsik, Joseph H.

    2013-03-29

    PNNL is conducting work to provide the technical basis for estimating radionuclide release from the engineered portion of the disposal facility for Hanford immobilized low-activity waste (ILAW). Before the ILAW can be disposed, DOE must conduct a performance assessment (PA) for the Integrated Disposal Facility (IDF) that describes the long-term impacts of the disposal facility on public health and environmental resources. As part of the ILAW glass testing program, PNNL is implementing a strategy, consisting of experimentation and modeling, to provide the technical basis for estimating radionuclide release from the glass waste form in support of future IDF PAs. Key activities in FY12 include upgrading the STOMP/eSTOMP codes to do near-field modeling, geochemical modeling of PCT tests to determine the reaction network to be used in the STOMP codes, conducting PUF tests on selected glasses to simulate and accelerate glass weathering, developing a Monte Carlo simulation tool to predict the characteristics of the weathered glass reaction layer as a function of glass composition, and characterizing glasses and soil samples exhumed from an 8-year lysimeter test. The purpose of this report is to summarize the progress made in fiscal year (FY) 2012 and the first quarter of FY 2013 toward implementing the strategy with the goal of developing an understanding of the long-term corrosion behavior of LAW glasses.

  7. The current status of glass leaching studies in France

    International Nuclear Information System (INIS)

    Glass has been selected in France as the material used to confine the activity of fission product solutions, and a continuous vitrification process has been developed at the Marcoule Vitrification Facility (AVM), the first industrial plant. Borosilicate glass was chosen in various compositions for its properties: it is a homogeneous, non-porous material that incorporates appreciable quantities of most of the fission product oxides, and is only alterable at the surface interface layer. Glass thus constitutes the primary radioactivity containment barrier, and it is essential to determine its long-term behavior. Water constitutes the principal hazard during temporary or definitive storage of the glass blocks. Two types of inherent material properties are studied from the standpoint of glass stability under leaching conditions: - chemical durability; - radioactive containability with regard to the various radionuclides, fission products and especially the actinides. Durability tests are carried out in SOXHLET devices and the alteration rates are measured by the weight loss. The containability is measured by the leach rate, i.e. by the rate of activity loss into the water. Leaching tests are conducted for several major objectives: - selection of glass compositions (leach rates); - leaching mechanism studies (hydrolyzed layer characteristics, effects of temperature, pressure, pH, etc.); - long-term behavior studies (glass specimens doped with alpha-emitters); - simulation of geological repository environments

  8. Electron beam induced cationic polymerization of epoxy resins. Dependence of Tg on conversion

    International Nuclear Information System (INIS)

    Complete text of publication follows. The high-energy radiation curing of monomer blends polymerizing by a free radical or by a cationic mechanism receives increasing attention in the perspective of high performance composite materials. In the present work, we have focused our attention on epoxy formulations as models of the matrices polymerizing by a cationic mechanism that could be used in fiber-reinforced composites for aerospace applications. We have examined the progress of the electron beam (EB) induced polymerization of diglycidylether of bisphenol A (DGEBA) in the presence of a diaryliodonium salt (DAIS) by FTIR spectroscopy and by dynamic mechanical thermal analysis (DMA). The obtained results allow to draw the gradual increase of the temperature for the network thermomechanical transition (Ta, associated with the glass transition temperature Tg) over a broad range of conversion (p) and reveal a peculiar behavior at high conversion. In this domain (p > 0.90), the material's Tg is shown to decrease when conversion approaches unity. Moreover, the post-irradiation thermal treatment of the materials, that generally yields effective 'dark curing', appears to induce a decrease of Tg, with an amplitude correlated with the amount of DAIS in the formulation. Owing to the particular nature of the propagating centers in cationic polymerisation, the thermal relaxation of ionic clusters trapped in the glassy matrix can be reasonably invoked as a possible cause for this behavior

  9. FIC glasses based upon AgI-TlI eutectic

    OpenAIRE

    Tanguy, B.; J. Portier; Rossignol, S; Reau, J.; Videau, J.

    1992-01-01

    New vitreous conductors, shown in the TeO2-Tl2O-AgI system, are described. The ionic conductivity in these glasses increases with the AgI content. Structure consists of a covalent TeO2-Tl2O network and a AgI sublattice with only a weak interaction between them. The AgI-TlI system offers a deep eutectic for the (AgI)0.75(TlI)0.25 composition with a melting point at 220°C. This favourable medium has been selected to prepare new silver FIC glasses. So, glasses belonging to the pseudo quaternary ...

  10. Paramagnetic centers induced by gamma irradiation of bioactive silica glasses containing yttrium

    International Nuclear Information System (INIS)

    Full text: Silica bioactive glasses containing neutron activated yttrium were investigated as a potential material for internal radiotherapy of cancers. The silica glasses, containing yttrium oxide and different alkali and alkaline-earth oxides as network modifiers, were obtained by melt annealing method. The samples were exposed to gamma radiation from a 60Co source for up to 10 days irradiation time. The radiation induced paramagnetic point defects in the irradiated glasses were analysed by Electron Paramagnetic Resonance (EPR). The EPR spectra of the silica glasses with different modifiers are characterised by a resonance line at g ≅ 2.024, slightly varying with the composition, attributed to a non-bridging oxygen hole centres. The addition of modifier oxides into glass network results in the formation of non-bridging oxygens that are locally charged compensated by modifier cations in neighbouring interstitial positions. The presence of small amount of boron oxide, up to 2.6 wt. %, in some of the glasses induced the formation of boron oxygen hole centres that are the main EPR species in these irradiated glasses. The presence of the EPR evidenced defects have to be taken into account as possible centres for glasses dissolution in human body during the radiotherapy procedure. (author)

  11. Crafting glass vessels: current research on the ancient glass collections in the Freer Gallery of Art, Washington, D.C.

    Science.gov (United States)

    Nagel, Alexander; McCarthy, Blythe; Bowe, Stacy

    Our knowledge of glass production in ancient Egypt has been well augmented by the publication of recently excavated materials and glass workshops, but also by more recent materials analysis, and experiments of modern glass-makers attempting to reconstruct the production process of thin-walled coreformed glass vessels. From the mounting of a prefabricated core to the final glass product our understanding of this profession has much improved. The small but well preserved glass collection of the Freer Gallery of Art in Washington, D.C. is a valid tool for examining and studying the technology and production of ancient Egyptian core formed glass vessels. Charles Lang Freer (1854-1919) acquired most of the material from Giovanni Dattari in Cairo in 1909. Previously the glass had received only limited discussion, suggesting that most of these vessels were produced in the 18th Dynasty in the 15th and 14th centuries BCE, while others date from the Hellenistic period and later. In an ongoing project we conducted computed radiography in conjunction with qualitative x-ray fluorescence analysis on a selected group of vessels to understand further aspects of the ancient production process. This paper will provide an overview of our recent research and present our data-gathering process and preliminary results. How can the examinations of core formed glass vessels in the Freer Gallery contribute to our understanding of ancient glass production and technology? By focusing on new ways of looking at old assumptions using the Freer Gallery glass collections, we hope to increase understanding of the challenges of the production process of core-vessel technology as represented by these vessels.

  12. Structurally Distinct Cation Channelrhodopsins from Cryptophyte Algae.

    Science.gov (United States)

    Govorunova, Elena G; Sineshchekov, Oleg A; Spudich, John L

    2016-06-01

    Microbial rhodopsins are remarkable for the diversity of their functional mechanisms based on the same protein scaffold. A class of rhodopsins from cryptophyte algae show close sequence homology with haloarchaeal rhodopsin proton pumps rather than with previously known channelrhodopsins from chlorophyte (green) algae. In particular, both aspartate residues that occupy the positions of the chromophore Schiff base proton acceptor and donor, a hallmark of rhodopsin proton pumps, are conserved in these cryptophyte proteins. We expressed the corresponding polynucleotides in human embryonic kidney (HEK293) cells and studied electrogenic properties of the encoded proteins with whole-cell patch-clamp recording. Despite their lack of residues characteristic of the chlorophyte cation channels, these proteins are cation-conducting channelrhodopsins that carry out light-gated passive transport of Na(+) and H(+). These findings show that channel function in rhodopsins has evolved via multiple routes. PMID:27233115

  13. Radiation chemistry of aromatic dimer radical cations

    International Nuclear Information System (INIS)

    π-π Interactions of aromatic molecules are paid attention much in many fields, especially biology, chemistry, and applied physics, represented as protein, DNA, electron donor-accepter complexes, charge transfers, and self assembly molecules. Aromatic molecules including benzene rings are the simplest case to study the π-π interactions. To interpret the charge resonance (CR) structure in the dimer radical cations, spectroscopic and ESR methods have been carried out. The spectroscopic study on the dimer radical ion of molecules with two chromophores would be profitable to identify the electronic and configurational properties. In this article, dynamics of the dimer radical cation of benzenes, polystyrenes, and resist polymers is described on the basis of direct observation of CR band by the nanosecond pulse radiolysis and low temperature γ-radiolysis methods. (author)

  14. Mechanism of adsorption of cations onto rocks

    International Nuclear Information System (INIS)

    Adsorption behavior of cations onto granite was investigated. The distribution coefficient (Kd) of Sr2+ and Ba2+ onto granite was determined in the solution of which pH was ranged from 3.5 to 11.3 and ionic strength was set at 10-2 and 10-1. The Kd values were found to increase with increasing pH and with deceasing ionic strength. The obtained data were successfully analyzed by applying an electrical double layer model. The optimum parameter values of the double layer electrostatics and adsorption reactions were obtained, and the mechanism of adsorption of cations onto granite was discussed. Feldspar was found to play an important role in their adsorption. (author)

  15. Planar Chiral, Ferrocene-Stabilized Silicon Cations.

    Science.gov (United States)

    Schmidt, Ruth K; Klare, Hendrik F T; Fröhlich, Roland; Oestreich, Martin

    2016-04-01

    The preparation of a series of planar chiral, ferrocenyl-substituted hydrosilanes as precursors of ferrocene-stabilized silicon cations is described. These molecules also feature stereogenicity at the silicon atom. The generation and (29) Si NMR spectroscopic characterization of the corresponding silicon cations is reported, and problems arising from interactions of the electron-deficient silicon atom and adjacent C(sp(3) )-H bonds or aromatic π donors are discussed. These issues are overcome by tethering another substituent at the silicon atom to the ferrocene backbone. The resulting annulation also imparts conformational rigidity and steric hindrance in such a way that the central chirality at the silicon atom is set with complete diastereocontrol. These chiral Lewis acid catalysts were then tested in difficult Diels-Alder reactions, but no enantioinduction was seen. PMID:26929105

  16. Ultrafast dynamics of water in cationic micelles.

    Science.gov (United States)

    Dokter, Adriaan M; Woutersen, Sander; Bakker, Huib J

    2007-03-28

    The effect of confinement on the dynamical properties of liquid water is investigated for water enclosed in cationic reverse micelles. The authors performed mid-infrared ultrafast pump-probe spectroscopy on the OH-stretch vibration of isotopically diluted HDO in D(2)O in cetyltrimethylammonium bromide (CTAB) reverse micelles of various sizes. The authors observe that the surfactant counterions are inhomogeneously distributed throughout the reverse micelle, and that regions of extreme salinity occur near the interfacial Stern layer. The authors find that the water molecules in the core of the micelles show similar orientational dynamics as bulk water, and that water molecules in the counterion-rich interfacial region are much less mobile. An explicit comparison is made with the dynamics of water confined in anionic sodium bis(2-ethythexyl) sulfosuccinate (AOT) reverse micelles. The authors find that interfacial water in cationic CTAB reverse micelles has a higher orientational mobility than water in anionic AOT reverse micelles. PMID:17411144

  17. Ultrafast dynamics of water in cationic micelles

    Science.gov (United States)

    Dokter, Adriaan M.; Woutersen, Sander; Bakker, Huib J.

    2007-03-01

    The effect of confinement on the dynamical properties of liquid water is investigated for water enclosed in cationic reverse micelles. The authors performed mid-infrared ultrafast pump-probe spectroscopy on the OH-stretch vibration of isotopically diluted HDO in D2O in cetyltrimethylammonium bromide (CTAB) reverse micelles of various sizes. The authors observe that the surfactant counterions are inhomogeneously distributed throughout the reverse micelle, and that regions of extreme salinity occur near the interfacial Stern layer. The authors find that the water molecules in the core of the micelles show similar orientational dynamics as bulk water, and that water molecules in the counterion-rich interfacial region are much less mobile. An explicit comparison is made with the dynamics of water confined in anionic sodium bis(2-ethythexyl) sulfosuccinate (AOT) reverse micelles. The authors find that interfacial water in cationic CTAB reverse micelles has a higher orientational mobility than water in anionic AOT reverse micelles.

  18. Glass and ceramics. [lunar resources

    Science.gov (United States)

    Haskin, Larry A.

    1992-01-01

    A variety of glasses and ceramics can be produced from bulk lunar materials or from separated components. Glassy products include sintered regolith, quenched molten basalt, and transparent glass formed from fused plagioclase. No research has been carried out on lunar material or close simulants, so properties are not known in detail; however, common glass technologies such as molding and spinning seem feasible. Possible methods for producing glass and ceramic materials are discussed along with some potential uses of the resulting products.

  19. Micromachining soda-lime glass by femtosecond laser pulses

    Science.gov (United States)

    Jia, Wei; Yu, Jian; Chai, Lu; Wang, Ching-Yue

    2015-08-01

    The physical process of forming a modified region in soda-lime glass was investigated using 1 kHz intense femtosecond laser pulses from a Ti: sapphire laser at 775 nm. Through the modifications induced by the femtosecond laser radiation using selective chemical etching techniques, we fabricated reproducible and defined microstructures and further studied their morphologies and etching properties. Moreover, a possible physical mechanism for the femtosecond laser modification in soda-lime glass was proposed.

  20. Development and modification of glass membranes for aggressive gas separations

    Energy Technology Data Exchange (ETDEWEB)

    Lindbraaten, Arne

    2004-07-01

    Chlorine as a chemical is widespread in industry and found in a great variety of processes ranging from water purification to plastic production. In this thesis, a magnesium production factory was chosen as an example because it involved both chlorine - air separation and hydrogen -hydrogen chloride separation. Previously, various types of membrane materials have been tested out for their applicability in the chosen process. The materials previously tested either lacked sufficient membrane performance or sufficient membrane stability. As an attempt to improve both the membrane performance and stability, glass membranes are used in this thesis. Glass membranes are prepared from a borosilicate glass, via a phase separation followed by an acid leaching route. By choosing the appropriate phase separation temperature and acid to glass ratio, the membrane can be produced with an average pore diameter of 2 nm (or 4 nm). However, the 2 nm average pore size is still too large to separate gases with separation selectivities beyond the selectivities predicted from Knudsen diffusion theory. If the pores are narrowed, the selectivity may be raised while the flux hopefully is maintained. The narrowing of the pores was done by a silane coupling to the surface OH-groups on the glass. The silane coupling agent is of the dimethyl-acyl-chlorosilane type, where the length of the acyl chain varies from 1 carbon up to 18 carbons. Glass fibres are also tested in this work, which are produced without phase separation and their average pore size is smaller than the surface-modified glasses. To be able to compare the performance of the various membranes, performance measurements are performed and these measurements are evaluated by the separation power (product of the selectivity and the permeability of the fastest permeating compound). Because of the harsh chlorine or hydrogen chloride environment, to which the membranes are exposed in this work, the membrane stability is at least as

  1. Stained-Glass Pastels

    Science.gov (United States)

    Laird, Shirley

    2009-01-01

    The author has always liked the look of stained-glass windows. Usually the designs are simplified and the shapes are easier for younger students to draw. This technique seemed to be the perfect place for her fifth-graders to try their hand at color mixing. The smaller spaces and simple shapes were just what she needed for this group. Her students…

  2. "Stained Glass" Landscape Windows

    Science.gov (United States)

    Vannata, Janine

    2008-01-01

    Both adults and children alike marvel at the grand vivid stained-glass windows created by American artist Louis Comfort Tiffany. Today he is commonly recognized as one of America's most influential designers and artists throughout the last nineteenth and early twentieth century. In the lesson described in this article, students created their own…

  3. Glass as matter

    DEFF Research Database (Denmark)

    Beim, Anne

    2000-01-01

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

  4. Microwave Glass Melting Technology

    Czech Academy of Sciences Publication Activity Database

    Hájek, Milan

    Tokyo, 2001, s. 11-14. [Conference on Application of Microwave Energy in Industry. Tokyo (JP), 30.07.2001-03.08.2001] R&D Projects: GA AV ČR IBS4072003 Institutional research plan: CEZ:AV0Z4072921 Keywords : microwave * glass melting technology * application Subject RIV: CI - Industrial Chemistry, Chemical Engineering

  5. What Glass Ceiling?

    Science.gov (United States)

    Lynch, Michael; Post, Katherine

    1996-01-01

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

  6. Glass ceilings of professionalisation.

    Science.gov (United States)

    Stott, Dawn L

    2016-04-01

    The term glass ceiling is a political term often used to describe an unbreakable barrier that isnot visible with the human eye, but it keeps minorities from rising up i.e. it is a barrier to minoritygroups, in the past (and sometimes still) for women, that stops them from achieving theirtrue potential. PMID:27290754

  7. Proton dynamics investigation for dimethyl ammonium cation

    International Nuclear Information System (INIS)

    Proton dynamics in dimethyl ammonium cation has been investigated by means of NMR and spin echo methods in polycrystalline salts [NH2(CH3)2]+Bi2J9- and [NH2(CH3)2]+SbJ9-. Spin-lattice relaxation time as well as second moment of NMR line have been measured for influence study of crystal structure changes on proton dynamics

  8. Alkaline earth cation extraction from acid solution

    Science.gov (United States)

    Dietz, Mark; Horwitz, E. Philip

    2003-01-01

    An extractant medium for extracting alkaline earth cations from an aqueous acidic sample solution is described as are a method and apparatus for using the same. The separation medium is free of diluent, free-flowing and particulate, and comprises a Crown ether that is a 4,4'(5')[C.sub.4 -C.sub.8 -alkylcyclohexano]18-Crown-6 dispersed on an inert substrate material.

  9. Rabbit cationic protein enhances leukocyte adhesiveness.

    OpenAIRE

    Oseas, R S; Allen, J; Yang, H. H.; Baehner, R. L.; Boxer, L A

    1981-01-01

    Cationic protein purified from rabbit peritoneal polymorphonuclear leukocytes (PMN) was demonstrated to incite autoaggregation of the rabbit PMN and promote adhesiveness of human PMN to endothelial cells. PMN aggregation induced by supernatants derived from secretory PMN was blocked by a specific anticationic protein antibody. These studies reveal that a positively charged protein derived from the PMN can alter surface properties of the PMN itself and imply a role for this protein in PMN immo...

  10. Mechanistic views on aromatic substitution reactions by gaseous cations.

    Science.gov (United States)

    Fornarini, S

    1996-01-01

    Recent advances in the understanding of the gas-phase reaction of aromatics with cationic electrophiles in a thermally equilibrated domain are described. The overall substitution reaction is analyzed in terms of its elementary steps. Their contribution to the overall reactivity pattern is dissected by the use of selected systems, which allowed one to highlight the kinetic role of single elementary events. Mechanistic studies have focused on the structure and reactivity of covalent and non-covalent ionic intermediates, which display a rich chemistry and provide benchmark reactivity models. Particular interest has been devoted to proton transfer reactions, which may occur in either an intra- or intermolecular fashion in arenium intermediates. A quantitative study of their rates and associated kinetic isotope effects is reported. © 1997 John Wiley & Sons, Inc. Mass Spectrom Rev 15(6), 365-389, 1997. PMID:27082944

  11. Cationic chalcone antibiotics. Design, synthesis, and mechanism of action.

    Science.gov (United States)

    Nielsen, Simon F; Larsen, Mogens; Boesen, Thomas; Schønning, Kristian; Kromann, Hasse

    2005-04-01

    This paper describes how the introduction of "cationic" aliphatic amino groups in the chalcone scaffold results in potent antibacterial compounds. It is shown that the most favorable position for the aliphatic amino group is the 2-position of the B-ring, in particular in combination with a lipophilic substituent in the 5-position of the B-ring. We demonstrate that the compounds act by unselective disruption of cell membranes. Introduction of an additional aliphatic amino group in the A-ring results in compounds that are selective for bacterial membranes combined with a high antibacterial activity against both Gram-positive and -negative pathogens. The most potent compound in this study (78) has an MIC value of 2 muM against methicillin resistant Staphylococus aureus. PMID:15801857

  12. Yesterday's Trash Makes Tomorrow's "Glass"

    Science.gov (United States)

    Wayne, Dale

    2010-01-01

    In this article, the author describes a glass art project inspired by Dale Chihuly. This project uses two-liter plastic soda bottles which are cut apart and trimmed. Applying heat using a hair dryer, the plastic curls and takes an uneven blown-glass quality. The "glass" is then painted using acrylic paint. (Contains 2 resources and 1 online…

  13. Glasses and nuclear waste vitrification

    International Nuclear Information System (INIS)

    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)

  14. Molecular Mobility in Sugar Glasses

    NARCIS (Netherlands)

    Dries, van den I.J.

    2000-01-01

    Glasses are liquids that exhibit solid state behavior as a result of their extremely high viscosity. Regarding their application to foods, glasses play a role in the preservation of foods, due to their high viscosity and the concomitant low molecular mobility. This thesis focuses on sugar glasses. S

  15. Limited data speaker identification

    Indian Academy of Sciences (India)

    H S Jayanna; S R Mahadeva Prasanna

    2010-10-01

    In this paper, the task of identifying the speaker using limited training and testing data is addressed. Speaker identification system is viewed as four stages namely, analysis, feature extraction, modelling and testing. The speaker identification performance depends on the techniques employed in these stages. As demonstrated by different experiments, in case of limited training and testing data condition, owing to less data, existing techniques in each stage will not provide good performance. This work demonstrates the following: multiple frame size and rate (MFSR) analysis provides improvement in the analysis stage, combination of mel frequency cepstral coefficients (MFCC), its temporal derivatives $(\\Delta,\\Delta \\Delta)$, linear prediction residual (LPR) and linear prediction residual phase (LPRP) features provides improvement in the feature extraction stage and combination of learning vector quantization (LVQ) and gaussian mixture model – universal background model (GMM–UBM) provides improvement in the modelling stage. The performance is further improved by integrating the proposed techniques at the respective stages and combining the evidences from them at the testing stage. To achieve this, we propose strength voting (SV), weighted borda count (WBC) and supporting systems (SS) as combining methods at the abstract, rank and measurement levels, respectively. Finally, the proposed hierarchical combination (HC) method integrating these three methods provides significant improvement in the performance. Based on these explorations, this work proposes a scheme for speaker identification under limited training and testing data.

  16. [Antioxidant activity of cationic whey protein isolate].

    Science.gov (United States)

    titova, M E; Komolov, S A; Tikhomirova, N A

    2012-01-01

    The process of lipid peroxidation (LPO) in biological membranes of cells is carried out by free radical mechanism, a feature of which is the interaction of radicals with other molecules. In this work we investigated the antioxidant activity of cationic whey protein isolate, obtained by the cation-exchange chromatography on KM-cellulose from raw cow's milk, in vitro and in vivo. In biological liquids, which are milk, blood serum, fetal fluids, contains a complex of biologically active substances with a unique multifunctional properties, and which are carrying out a protective, antimicrobial, regenerating, antioxidant, immunomodulatory, regulatory and others functions. Contents of the isolate were determined electrophoretically and by its biological activity. Cationic whey protein isolate included lactoperoxidase, lactoferrin, pancreatic RNase, lysozyme and angeogenin. The given isolate significantly has an antioxidant effect in model experimental systems in vitro and therefore may be considered as a factor that can adjust the intensity of lipid oxidation. In model solutions products of lipid oxidation were obtained by oxidation of phosphatidylcholine by hydrogen peroxide in the presence of a source of iron. The composition of the reaction mixture: 0,4 mM H2O2; 50 mcM of hemin; 2 mg/ml L-alpha-phosphatidylcholine from soybean (Sigma, German). Lipid peroxidation products were formed during the incubation of the reaction mixture for two hours at 37 degrees C. In our studies rats in the adaptation period immediately after isolation from the nest obtained from food given orally native cationic whey protein isolate at the concentration three times higher than in fresh cow's milk. On the manifestation of the antioxidant activity of cationic whey protein isolate in vivo evidence decrease of lipid peroxidation products concentration in the blood of rats from the experimental group receipt whey protein isolate in dos 0,6 mg/g for more than 20% (pwhey protein isolate has an

  17. In situ one-year burial experiments with simulated nuclear waste glasses

    International Nuclear Information System (INIS)

    Two simulated nuclear waste glasses were corroded in an in-situ experiment in the Stripa mine up to one year at 90 degree C and ambient temperature. Changes in compositional in-depth profiles were measured using Fourier transform infrared reflection spectroscopy, SIMS and Rutherford back-scattering. For glass/glass interfaces, both glasses showed depletion of Na, Cs and B, but for the more corrosion resistant glass, the lower depletion is ascribed to the formation of a thin (0.2 nm) coherent and dense outer layer enriched in Mg, Ca, Sr, Ba, Zn-Al and Si, which impedes both ion exchange and network attack of the bulk underneath. For the bentonite interfaces, cation exchange of Ca, Mg, Al and Fe from the bentonite for primarily Na and B is found to produce a glass surface that has three silicate-rich layers. The larger concentrations of M/super2+/ and M/super3+/ cation and the high silica content of the reaction layers result in a considerably retarded rate of ion exchange after the formation of these layers during the first three months of burial. The granite interfaces showed the lowest rate of attack. This appears to be due to a large increase of Fe and Al within the glass surfaces exposed to granite. The results obtained using Rutheford back-scattering confirm the results obtained using the other techniques for surface analysis. Analysis of burial samples cast in steel mini-canisters show no significant effects associated with the steel canister-glass interface. (author)

  18. Forward dissolution rate of silicate glasses of nuclear interest in clay-equilibrated groundwater

    International Nuclear Information System (INIS)

    This study describes the influence of neutral or slightly basic clay-equilibrated groundwater on the forward dissolution rate of nuclear borosilicate glasses. The forward rate measured for the SON68 glass, a 26-oxide glass of nuclear interest, is about five times higher in clay-equilibrated groundwater than in deionized water. The corresponding apparent activation energy, measured between 30 degrees C and 90 degrees C. is similar for both media, indicating that glass dissolution is likely controlled by the hydrolysis of Si-O bonds in both solutions. The specific effect of clay-equilibrated groundwater appears to be related to a surface phenomenon; aluminum-oxygen and zirconium-oxygen bonds appear to be less impacted by clay-equilibrated groundwater than silicon-oxygen bonds. More particularly, this work shows that the influence of clay-equilibrated groundwater on the forward dissolution rate is due to its ionic strength with cations predominating over anions, although not all tested cations have the same effect. The effect is due mainly to calcium ions, although the concentration of sodium ions in the clay-equilibrated water tested was four times higher than that of calcium ions. The specific influence of alkali metal (Li+, Na+, K+, Rb+, Cs+) and alkaline earth (Mg2+, Ca2+, Sr2+, Ba2+) ions shows that all cations do not have the same effect on the forward glass dissolution rate and that the rate increases with the mole fraction of surface metal sites. The presence of calcium in the glass does not prevent this particular effect. (authors)

  19. Thermal Conductivity of Foam Glass

    OpenAIRE

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

    2014-01-01

    Due to the increased focus on energy savings and waste recycling foam glass materials have gained increased attention. The production process of foam glass is a potential low-cost recycle option for challenging waste, e.g. CRT glass and industrial waste (fly ash and slags). Foam glass is used as thermal insulating material in building and chemical industry. The large volume of gas (porosity 90 – 95%) is the main reason of the low thermal conductivity of the foam glass. If gases with lower the...

  20. Space-Selective Precipitation of Ba2TiSi2O8 Crystals in Sm3+-Doped BaO-TiO2-SiO2 Glass by Femtosecond Laser Irradiation

    Institute of Scientific and Technical Information of China (English)

    ZHU Bin; DAI Ye; MA Hong-Liang; LIN Geng; QIU Jian-Rong

    2008-01-01

    The ferroelectric crystal Ba2TiSi2O8 with high second-order optical nonlinearity is precipitated in Sm3+-doped BaO-TiO2-SiO2 glass by a focused 800 nm,250 kHz and 150 fs femtosecond laser irradiation.No apparent blue and red emissions are observed at the beginning,while strong blue emission due to second harmonic generation and red emission due to the f-f transitions of Sm3+ are observed near the focal point of the laser beam after irradiation for 25 s. Micro-Raman spectra confirm that Ba2TiSi2O8 crystalline dots and lines are formed after laser irradiation.The mechanism of the phenomenon is discussed.

  1. A critical study of the emergence of glass and glassy metals as “green” materials

    International Nuclear Information System (INIS)

    Highlights: • We provide a study on the capabilities of glass/glassy metals as green materials. • A well materials selection provides certain strategic and competitive advantages. • Points of view on the actually and future influence of these materials are done. • Glasses are materials that are fully recyclable, with a life cycle perfectly closed. • Glassy metals are considered to be among the emerging materials of the future. - Abstract: In 2008, The National Academy of Engineering (NAE – Washington, DC) identified the glass family (glasses, glass ceramics and glass composites) as central to many of the great engineering achievements of the twentieth century: the development of solid state lasers and optical glass fibers, biomaterials, glasses for imaging technologies, and glass films in microelectronic devices. The work reported in this paper discusses the importance of glass and metallic glasses as environmental friendly materials and also provide some points of view about the future influence of these materials for the related fields of industrial engineering and industrial ecology. The environmental capabilities of metallic glasses (MGs), which are considered to be among the important materials of the future, have not been sufficiently investigated. However, some aspects have yet to be done: the biocompatibility of most MGs, obtaining valuable MGs from waste materials, using MGs in green energy applications (solar cells and hydrogen production), using MGs in catalyst systems, as well as the possibility for using MGs in systems for retention and purification of dangerous pollutants and in the nuclear industry

  2. The performance of Glass GEM

    Science.gov (United States)

    Fujiwara, T.; Mitsuya, Y.; Takahashi, H.; Fushie, T.; Kishimito, S.; Guèrard, B.; Uesaka, M.

    2014-11-01

    Here we report the performance of Glass gas electron multipliers (Glass GEMs), which were fabricated with photo-etchable glass. The photo-etchable glass used for substrate is called PEG3 (Hoya Corporation). With this material, we succeeded in fabricating a Glass GEM that was 680 μ m-thick with a hole diameter of 170 μ m and Cr and Cu layer electrodes. A Glass GEM has advantages such as good uniformity, high gain, a flat surface without stretching, cylindrical holes, and the absence of outgassing from the material. We successfully operated a Glass GEM having 100 × 100 m 2 effective area with various gas mixtures. The energy resolution for 5.9 keV X-rays was 18%, obtained by uniform irradiation of the entire effective area. The gas gain of the Glass GEM reached up to 90,000 with a gas mixture of Ne/C 4 (90:10). The Glass GEM was also operated with Ar/C 4 and Ar/C 4 gas. The gain stability measured for Glass GEM showed no significant increase or decrease as a function of elapsed time from applying high voltage. The gain stability over 15 hours of operation was about 10% in high-count-rate irradiation. Gain mapping across the Glass GEM showed good uniformity with a standard deviation of about 10%.

  3. Commercial and Experimental Glass Fibers

    Science.gov (United States)

    Wallenberger, Frederick T.

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

  4. Low thermal expansion glass ceramics

    CERN Document Server

    1995-01-01

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

  5. Fluoride glass: Crystallization, surface tension

    Science.gov (United States)

    Doremus, R. H.

    1988-01-01

    Fluoride glass was levitated acoustically in the ACES apparatus on STS-11, and the recovered sample had a different microstructure from samples cooled in a container. Further experiments on levitated samples of fluoride glass are proposed. These include nucleation, crystallization, melting observations, measurement of surface tension of molten glass, and observation of bubbles in the glass. Ground experiments are required on sample preparation, outgassing, and surface reactions. The results should help in the development and evaluation of containerless processing, especially of glass, in the development of a contaminent-free method of measuring surface tensions of melts, in extending knowledge of gas and bubble behavior in fluoride glasses, and in increasing insight into the processing and properties of fluoride glasses.

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

    Science.gov (United States)

    Kelly, M.D.; Kramer, D.P.

    1985-01-04

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

  7. Structural Investigation of SBGESE Glasses by High Resolution X-Ray Photoelectron Spectroscopy

    Directory of Open Access Journals (Sweden)

    R. Golovchak

    2011-01-01

    Full Text Available The evolution of the structure of Sb8Ge32Se60 (Z=2.72 and Sb20Ge20Se60 (Z=2.60 chalcogenide glasses is determined by high resolution X-ray photoelectron spectroscopy. Glasses with Z=2.60 the structure consists of deformed tetrahedra and pyramids, in which at least one Se atom is substituted by Ge or Sb atom. For the Z=2.72 structure consisting of shared pyramids and tetrahedra with two or more Se atoms substituted by the cations. At the same time, Se-Se dimers are present in both compositions.

  8. Development on Glass Formulation for Aluminum Metal and Glass Fiber

    International Nuclear Information System (INIS)

    Vitrification technology has been widely applied as one of effective processing methods for wastes generated in nuclear power plants. The advantage of vitrifying for low- and intermediate-level radioactive wastes has a large volume reduction and good durability for the final products. Recently, a filter using on HVAC(Heating Ventilating and Air Conditioning System) is composed with media (glass fiber) and separator (aluminum film) has been studied the proper treatment technology for meeting the waste disposal requirement. Present paper is a feasibility study for the filter vitrification that developing of the glass compositions for filter melting and melting test for physicochemical characteristic evaluation. The aluminum metal of film type is preparing with 0.5 cm size for proper mixing with glass frit, glass fiber is also preparing with 1 cm size within crucible. The glass compositions should be developed considering molten glass are related with wastes reduction. Glass compositions obtained from developing on glass formulation are mainly composed of SiO2and B2O3for aluminum metal. A variety of factors obtained from the glass formulation and melting test are reviewed, which is feeding rate and glass characteristics of final products such as durability for implementing the wastes disposal requirement.

  9. Protein structure and ionic selectivity in calcium channels: Selectivity filter size, not shape, matters

    OpenAIRE

    Malasics, Attila; Gillespie, Dirk; Nonner, Wolfgang; Henderson, Douglas; Eisenberg, Bob; Boda, Dezső

    2009-01-01

    Calcium channels have highly charged selectivity filters (4 COO− groups) that attract cations in to balance this charge and minimize free energy, forcing the cations (Na+ and Ca2+) to compete for space in the filter. A reduced model was developed to better understand the mechanism of ion selectivity in calcium channels. The charge/space competition (CSC) mechanism implies that Ca2+ is more efficient in balancing the charge of the filter because it provides twice the charge as Na+ while occupy...

  10. A Color-texture Approach Based on Mutual Information for Multispectral Image Classification

    Directory of Open Access Journals (Sweden)

    Hassan El Maia

    2010-10-01

    Full Text Available In this work we propose an approach to improve the results of color texture image classification. We construct a new space called hybrid color-texture space by selecting the most discriminating attributes for the textures. Attributes are calculating from the co-occurrence matrix. The selection is done by the algorithm MRMR based on the mutual information. The Support Vectors Machine classifier (SVMis used. A comparison with an iterative selection is also performed. The effectiveness of the proposed approach is evaluated on the VisTex database and on a SPOT HRV (XS image representing two forest areas in the region of Rabat.

  11. Glass manufacturing through induction

    International Nuclear Information System (INIS)

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

  12. Irradiation effects in glasses

    International Nuclear Information System (INIS)

    The deposition of irradiation energy can alter the physical properties of glasses through bond-breaking (energetic photons; fast particles) and atomic displacements (Coulombic and collisional: n0, e, ions). These processes can alter UV-visible optical properties via electron-hole trapping and IR-spectra as a result of network damage. The movement of network atoms results in volume dilatation which change the hardness, refractive index, and dissolution rates. All of these changes can be realized with ion implantation and, in addition, implantation of chemically active species can lead to compound formation in the implanted regions. For this reason, emphasis will be placed on the implantation-induced surface modifications of glasses (mostly silicates). The paper includes crystallization, surface stress, refractive index changes and optoelectronic application and chemical reactivity

  13. Glasses for Mali

    CERN Multimedia

    PH Department

    2008-01-01

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

  14. Preface JFDE Special Issue Glass

    Directory of Open Access Journals (Sweden)

    Ulrich Knaack

    2015-05-01

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

  15. Nuclear traces in glass

    International Nuclear Information System (INIS)

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

  16. Amorphous gauge glass theory

    International Nuclear Information System (INIS)

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

  17. Shielding property of bismuth glass based on MCNP 5 and WINXCOM simulated calculation

    International Nuclear Information System (INIS)

    Background: Currently, lead glass is widely used as observation window, while lead is toxic heavy metal. Purpose: Non-toxic materials and their shielding effects are researched in order to find a new material to replace lead containing material. Methods: The mass attenuation coefficients of bismuth silicate glass were investigated with gamma-ray's energy at 0.662 MeV, 1.17 MeV and 1.33 MeV, respectively, by MCNP 5 (Monte Carlo) and WINXCOM program, and compared with those of the lead glass. Results: With attenuation factor K, shielding and mechanical properties taken into consideration bismuth glass containing 50% bismuth oxide might be selected as the right material. Dose rate distributions of water phantom were calculated with 2-cm and 10-cm thick glass, respectively, irradiated by 137Cs and 60Co in turn. Conclusion: Results show that the bismuth glass may replace lead glass for radiation shielding with appropriate energy. (authors)

  18. Athermal photofluidization of glasses.

    Science.gov (United States)

    Fang, G J; Maclennan, J E; Yi, Y; Glaser, M A; Farrow, M; Korblova, E; Walba, D M; Furtak, T E; Clark, N A

    2013-01-01

    Azobenzene and its derivatives are among the most important organic photonic materials, with their photo-induced trans-cis isomerization leading to applications ranging from holographic data storage and photoalignment to photoactuation and nanorobotics. A key element and enduring mystery in the photophysics of azobenzenes, central to all such applications, is athermal photofluidization: illumination that produces only a sub-Kelvin increase in average temperature can reduce, by many orders of magnitude, the viscosity of an organic glassy host at temperatures more than 100 K below its thermal glass transition. Here we analyse the relaxation dynamics of a dense monolayer glass of azobenzene-based molecules to obtain a measurement of the transient local effective temperature at which a photo-isomerizing molecule attacks its orientationally confining barriers. This high temperature (T(loc)~800 K) leads directly to photofluidization, as each absorbed photon generates an event in which a local glass transition temperature is exceeded, enabling collective confining barriers to be attacked with near 100% quantum efficiency. PMID:23443549

  19. Selective behavior of Anguilla japonica glass eel on substrate color and light intensity in the Yangtze Estuary%长江口日本鳗鲡鳗苗对底质颜色和光照强度的选择行为

    Institute of Scientific and Technical Information of China (English)

    龚盼; 侯俊利; 庄平; 张涛; 刘鉴毅; 黄晓荣; 章龙珍

    2015-01-01

    采用个体和群体相结合的实验方法,研究了长江口日本鳗鲡(Anguilla japonica)鳗苗对底质颜色和光照强度的选择行为。结果表明:在室内光照(88 lx)和黑暗(0.3 lx)条件下,鳗苗在个体和群体实验中对黑、白底质颜色的选择均有显著性差异(P<0.05),其对黑色底质有明显偏好。鳗苗对4个光照强度梯度:6000~12000 lx(A区)、700~1400 lx(B区)、60~150 lx(C区)和5~10 lx(D区)的选择性也表现出显著性差异,实验中个体和群体在D区活动的时间和数量百分比均显著高于其它区域(P<0.05),表明日本鳗鲡鳗苗对5~10 lx的弱光有明显趋性。由长江口日本鳗鲡鳗苗趋向黑色底质和弱光环境的结果推测,长江口鳗苗可能营底栖生活,白天强光照期间栖息于河口区光照强度较低的底层,并于夜间借助潮汐能进行溯河洄游,同时具有躲避敌害、避免被捕食的作用,以尽快适应生态环境变化并成功快速进入淡水水域育肥。%Purpose:The paper is to investigate selective behavior of Anguilla japonica glass eel for environmental factors,to offer a guide for management and protection of Japanese eel stock. Materials:Anguilla japonica glass eel [(57.52 ±2.61)mm,(0.115 ±0.025)g ]captured from the Yangtze Estuary in April 2014 was kept for 2 weeks in an aquarium,and fed to satiation twice a day at 8∶00 am and 18∶00 pm.The temperature and dissolved oxygen of the breeding water was controlled at (25 ±1)℃and 7 mg·L-1 respectively,and water ammonia nitrogen was less than 0.01 mg·L-1 . Methods:The experiment for preference of substrate color and light intensity used individual (30 ind) and population glass eel (30 ind ).Individual experiment index was defined as the percentage of glass eel active time in each area.Population experiment index was defined as the percentage of glass eel number active in each area

  20. Indentation recovery of soda-lime silicate glasses containing titania, zirconia and hafnia at low temperatures

    International Nuclear Information System (INIS)

    Highlights: ► The addition of titania, zirconia and hafnia in soda-lime silicate glass increases density, elastic moduli, Vickers hardness and brittleness. ► The effect of titania, zirconia and hafnia on the indentation recovery of soda-lime silicate glass is studied at 25 °C and 100 °C. ► The highest indentation recovery rate of glasses is observed within the first 6 h. ► The indentation recovery rate of glasses decreases with the increase in the size of tetravalent metal cations added. ► All the indentations exhibit three common features: elasticity, viscoelasticity and plasticity. - Abstract: From thermal treatment of indentations made on glass, the densification contribution to the total indentation deformation can be estimated. In this work, we studied the physico-mechanical properties and low-temperature indentation recovery of soda-lime silicate glasses with the composition of (in wt%) 73SiO2–12CaO–15Na2O–xTiO2 (ZrO2 or HfO2), where x is 0, 1, 2, 4 and 8. The obtained results demonstrated that the addition of group IV B metal oxides (TiO2, ZrO2 and HfO2) into soda-lime silicate glass increased density, elastic moduli, Vickers hardness and brittleness due to the higher atomic weight of additives, increased network connectivity, higher strength of individual bonds formed and lower molar volume, respectively. Indentation recovery of glass samples containing 8 wt% TiO2 (G5), 8 wt% ZrO2 (G9) and 8 wt% HfO2 (G13) was comparatively estimated with that of a pure soda-lime silicate glass (G1), as a reference, on the basis of the depth change of indentation impressions at low temperatures, 25 °C and 100 °C, for different periods with a maximum of 48 h. It was found that the higher indentation recovery for all four samples was observed at both temperatures within the first 6 h due to stored strain energy in deformation zone but equilibrium was not reached even after 48 h because of low thermal treatment temperatures, which generally provide a